Within the past few years a variety of further
MDR-associated genes was identified: mainly the discovery of the MDR-
associated protein MRP1 going along with its family members MRP2 to MRP6 of
this transporter family (Cole et al, 1992; Borst et al, 1999) and the lung
resistance-related protein (LRP) acting as the major vault protein in the
nucleocytoplasmic transport (Scheper et al, 1993). They confer the MDR
phenotype that is distinct in pattern from mdr1-related resistance, but
includes many of the same drugs. MRP belongs to the ABC transporter gene
superfamily and operates as an ATP-dependent primary active transporter for
substrates conjugated with glucuronide or glutathione (Ishikawa et al, 2000).
Overexpression of MRP and LRP is frequently observed in primary NSCLC, especially
in the well-differentiated squamous cell carcinomas (Nooter et al, 1996) and
expression is significantly higher in NSCLC samples when compared to SCLC
samples (Dingemanns et al, 1996). There is also evidence that expression of
MRP1 and LRP can be upregulated by sublethal exposure of lung cancer cells to
some MDR-related drugs (Berger et al, 2000; Yoshida et al, 2001). Ota et al,
(1995) examined the levels of expression of MRP in 104 NSCLC and found that MRP
overexpression was associated with a worse prognosis in patients that received
postoperative chemotherapy with MRP-related anticancer drugs
(vindesine/etoposide). However, the concomitant operation of several resistance
mechanisms may be often necessary to cause the MDR phenotype. Experimental data
indicate that the genes coding for P-gp, MRP and LRP are differentially
regulated by extracellular stimuli.
B. Glutathione-dependent enzymes
Another important arsenal that cells utilize to
detoxify the cytotoxic effects of anticancer drugs are glutathione (GSH) and
the GSH-related enzymes glutathione S-transferase (GST) and glutathione
peroxidase (GPX). GST catalyzes the conjugation of electrophilic metabolites to
GSH to facilitate their excretion. GPX utilizes GSH to remove reactive oxygen
intermediates. GSH and its related enzymes are ubiquitously distributed in many
normal tissues as well as tumors and are involved in resistance to a wide
variety of drugs such as alkylating agents, anthracyclines and vinca alkaloids
(Tew, 1994). There is increasing evidence that these enzymes are a determinant
factor in the sensitivity of lung tumors to anticancer drugs (Carmichael et al,
1988; Sharma et al, 1993). GST isoenzymes are found in significant amounts in
bronchioles and alveoli of normal lung (Awasthi et al, 1987) and most intensely
in the bronchial epithelium (Anttila et al, 1993). A number of studies have
shown that the amount of GST isoenzymes is even higher in tumors of the lung
relative to the surrounding normal tissue (Di Ilio et al, 1988; Clapper et al,
1991). In particular, high levels of glutathione-dependent enzymes have been
detected in cell lines derived from NSCLC compared to SCLC cell lines (DĠArpa
and Liu, 1989). It is speculated that these alterations could account for the
differences in drug sensitivity between these tumor types. Evidence that GST
may be involved in drug resistance has come from the generation of
drug-resistant cell lines in vitro and from transfection studies with GST cDNAs
(Nakagawa et al, 1990). Changes in GST expression are most marked in cell lines
made resistant to nitrogen mustard compounds and nitrosoureas and redox cycling
drugs such as doxorubicin (Whelan et al, 1989). GST-p isoenzyme is also overexpressed in lung tumors of
smokers compared to nonsmokers (Volm et al, 1991).
It is suggested that GST overexpression may be a part
of an adaptive response to enviromental stress to protect against toxic injury.
Frequently, a coexpression of P-gp and GST-p is found (Volm et al, 1991; Linsenmeyer et al, 1992). But also a
coordinated induction of MRP1 and GSH-related enzymes is reported in malignant
cells after exposure to cytostatic agents (Van der Kolk et al, 1999). These
observations led to the suggestions that these genes share common regulatory
mechanisms, and that perhaps a single transcription factor or regulating
protein may be involved in their regulation. However, it is unlikely that
alterations in the GST are causally related to the development of drug
resistance in lung tumors, but rather that co-modification along with other
resistance-related enzymes could mediate drug resistance.
Besides these detoxifying enzymes, normal lung is also
efficiently protected against exogenous free radicals by antioxidant enzymes
(AOEs). Major human AOE include superoxide dismutases, catalase and enzymes
associated with GSH metabolism, all of which are expressed in human lung. In
addition, human lung also expresses several thiol-containing proteins including
the families of thioredoxins, thioredoxin reductases and peroxiredoxins. Their
expression in human lung is located mainly to alveolar macrophages, bronchial
epithelial cells and alveolar epithelium, critical areas in the oxidant
protection of human lung (Kinnula et al, 2004). These proteins not only have
effects on cell proliferation and cell death, but also protect both
non-malignant and malignant cells against radiation and chemotherapy. The
redox-regulating proteins are highly expressed in lung tumors (Soini et al,
2001) and are associated with lymph node status and prognosis in NSCLC (Kakolyris
et al, 2001). Peroxiredoxins also have effects on the progression and prognosis
of lung cancer (Lehtonen et al, 2004).
C. Topoisomerases
In addition to P-gp and non-P-gp-mediated MDR, other
mechanisms for resistance to multiple drugs have been described including
frequent alterations of topoisomerase II (topo II) activity (Eijdems et al,
1985; Cole et al, 1991). Topo II is an ubiquous nuclear enzyme that is
essential for many aspects of DNA function, including replication,
recombination and transcription. There is evidence that this enzyme is the
target of many clinically important antineoplastic drugs such as
anthracyclines, ellipticines, amsacrines and epipodophyllotoxins (DĠArpa and
Liu, 1989; Zijlstra et al, 1990). These drugs stabilize the cleavable complex
formed between topo II and DNA, resulting in increased DNA excision, detectable
as DNA single-strand or double-strand breaks, and DNA-protein cross-links.
Drug-induced cell destruction is proportional to the level of topo II, the more
enzyme the greater the toxicity. This explains how a reduction in topo II could
be a major mechanism of resistance to many antineoplastic drugs. Topo II has
also been reported to play a role in cell proliferation. High levels of this
enzyme are found in proliferating cells, and very low levels in quiescent cells
(Zijlstra et al, 1990).
In contrast, there are some reports that increased
topo II is associated with resistance to certain DNA-damaging agents (Dingemans
et al, 1999). It is also speculated that the increased affinity of topo II for
cross-linked DNA in alkylating agents-resistant cells contribute to alkylator
resistance by changing DNA topology, thereby facilitating DNA repair (Eder et
al, 1995; Pu and Bezwoda, 1999).
In surgical tissue samples of primary untreated lung
tumors, significant intra- and intertumor variation in topo II expression has
been observed. Topo II activity is higher in NSCLC as compared to breast cancer
(McLeod et al, 1994). On the other hand, topo II activities of SCLC cell lines
have been reported to be 2-fold higher than those for NSCLC cell lines,
corresponding to their sensitivities to doxorubicin and etoposide (Kasahara et
al, 1992). A correlation between topo II gene expression and sensitivity to
doxorubicin, etoposide and cisplatin was also found in lung cancer cell lines
not selected in vitro for drug resistance (Giaccone et al, 1992). Most lung
cancer cell lines selected for resistance to doxorubicin demonstrate decreased
levels of topo II expression in addition to P-gp overexpression (Eijdems et al,
1985). Therefore, low levels of topo II expression may predict reduced
sensitivity of human lung cancer to several drugs. However, as with mdr1/P-gp
expression, this cannot solely explain the drug-resistant phenotype of NSCLC.
D. Metallothioneins
Metallothioneins (MTs) are intracellular proteins of
low molecular weight (6-7 kDa) that are present in a wide variety of
eukaryotes. MT are characterized by a high content of cysteine and the ability
to bind heavy metal ions including zinc, copper, cadmium and platinum. The
physiological function of MT is not well understood. Most mammalian tissues
contain a basal level of MT, which may vary with the type of tissue. MT has
also been demonstrated in a variety of malignancies including colorectal tumors
(
fner et al, 1994), testicular germ cell tumors (Chin et al, 1993) and ovarian
tumors (Murphy et al, 1991). MT in lung cancer tissue is significantly elevated
when compared to nonmalignant lung tissue (Hart et al, 1993). The synthesis of
MT is easily inducible in lung or other organs by certain hormones, cytokines,
growth factors, tumor promotors and many other chemicals. Some stressful
environmental conditions such as heat, cold and starvation also induce MT
(Hamer, 1986).
Recently, the synthesis of MT by tumor cells has been
proposed as a possible mechanism for the intracellular inactivation of
metal-containing chemotherapeutic agents such as cisplatin. MT content and MT
mRNA levels correlated well with the sensitivity of SCLC cell lines to cisplatin
(Kasahara et al, 1991). A transfected cell line that overexpresses MT proved
not only resistant to cisplatin but also resistant to chlorambucil, melphalan
and doxorubicin (Kelley et al, 1988). However, cells of various origins
selected for cisplatin resistance often, but not always show increased MT
expression, suggesting that an increased MT expression alone may not be the
sole mediator of cisplatin resistance. Matsumoto et al, (1997) found that the
proportion of MT-positive tumors was significantly higher in treated NSCLC
compared with untreated NSCLC and treated SCLC, whereas Joseph et al, (2001)
demonstrated that MT overexpression was predictive of short-term survival in
patients with SCLC undergoing chemotherapy. In a study with human NSCLC, we found
a significant relationship between MT expression and doxorubicin resistance in
vitro (Mattern et al, 1992). Thus, a number of factors may be involved in the
development of drug resistance in lung tumor cells and expression of MT may be
one of them.
E.O6-alkylguanine-DNA alkyltransferase
A number of DNA-damaging anticancer agents attack the
O6 position on guanine, forming the potent cytotoxic DNA adduct. The DNA repair
enzyme O6-alkylguanine-DNA alkyltransferase (ATase), encoded by the gene MGMT, repairs alkylation at this site
and is responsible for protecting tumor and normal cells from these agents.
ATase activity varies widely among different organs,
with lung tissue on average lower than others (Citron et al, 1991). However,
ATase activity in normal peripheral lung tissue of smokers is significantly
higher than that of nonsmokers (Drin et al, 1994; Mattern et al, 1998). Most
human lung tumors contain amounts of ATase similar or greater than the tissue
from which they originate (Kelley et al, 1988). In SCLC, ATase was found to be
significantly lower than in NSCLC, but wide interindividual varaitions were
observed (Oberli-Schrmmli et al, 1994). However, approximately 12% of human
lung tumors are deficient in this enzyme (Citron et al, 1993). These ATase-deficient
tumors are very sensitive to the cytotoxic effects of agents that alkylate the
O6-position of guanine, such as nitrosoureas (Pegg, 1990).
Thus, evidence suggesting a possible role for ATase in
drug resistance of lung tumors comes from the following observations: (1) the
level of ATase in tumor cells correlates well with the sensitivity to
nitrosoureas (Brent et al, 1985), (2) transfection of the gene for
alkyltransferase to ATase-deficient cells decreases the sensitivity to
alkylating agents (Kaina et al, 1991), and (3) depletion of the activity of
this enzyme by addition of O6-benzylguanine significantly enhances toxicity
(Dolan et al, 1993). Whether the ATase gene is a member of and co-regulated
with other stress-responsive genes and controlled by a common set of
transcription factors remains to be elucidated.
F. Thymidylate synthase
Thymidylate synthase (TS) plays a central role in DNA
biosynthesis and is the target of many chemotherapeutic agents, such as
5-fluorouracil, methotrexate and fluorodeoxyuridine (Washtien, 1982). Moreover,
tumor cells resistant to cisplatin and doxorubicin display increased levels of
this enzyme (Scanlon et al, 1988; Chu et al, 1991). Human NSCLC strongly
express TS in a high percentage of cases (Volm and Mattern, 1992a; 1992b). This
expression of TS is significantly related to doxorubicin resistance in vitro
and associated with cross-resistance to 5-fluorouracil (Volm et al, 1979).
Moreover, TS-positive lung tumors have been noted to be clinically progressive,
the affected patients living a significantly shorter time than those with
TS-negative tumors (Volm and Mattern, 1992a). In addition, evaluation of
intratumoral TS activity accurately predicts responsiveness to 5-FU-based
chemotherapy in NSCLC patients (Huang et al, 2000; Shintani et al, 2004). It
has often been reported that the higher the TS level, the more resistant is the
cell to antineoplastic drugs, in particular to 5-fluorouracil (Johnston et al,
1995). However, the biological relevance of TS relates not only to the
importance of this enzyme as a chemotherapeutic target, but also as a DNA
synthetic enzyme associated with cell division and proliferation (Stammler et
al, 1995; Nakagawa et al, 2004). Nevertheless, high intrinsic levels of TS do
not necessarily lead to higher proliferation rates than in cases with low
levels of TS (Pestalozzi et al, 1995). A recent study has shown that TS protein
binds to c-myc mRNA suggesting an
involvement in the coordinate regulation of a number of other genes (Chu et al,
1994).
G. Cell cycle-related proteins
There exists general agreement that cancer
chemotherapy is most successful when used on rapidly growing malignant cells
(Valeriote and Van Putten, 1975). Experimental data obtained in a variety of
systems ranging from mammalian cell cultures to transplanted rodent tumors show
that proliferating cells are more sensitive to most cytotoxic agents than are
resting cells (Drewinko et al, 1981). These experimental data are supported by
the clinical observations that fast-growing tumors usually respond to
treatment, whereas tumors with a low rate of proliferation very often show no
response. To estimate the proliferative activity of cancer, various techniques
including 3H-thymidine labeling (Alama et al, 1990) or flow-cytometric analysis
(Volm et al, 1985; 1988) have been used. Several antibodies have also been
produced that label preferentially the nuclei of proliferating (Volm et al,
1995a) and nonproliferating cells (Volm et al, 1995b). Although human lung
tumors show a wide variation in proliferative activity and tumor doubling
times, NSCLC have on average lower labeling indices and longer doubling times
than SCLC, perhaps partly accounting for their resistance to cytotoxic drugs
(Muggia, 1974; Arai et al, 1994). Moreover, patients whose lung tumors have a
high proportion of cells in the S-phase generally die earlier than patients
whose tumors have a low proportion of these cells (Alama et al, 1990; Volm et
al, 1985; 1988; 1995). Thus, the determination of cell proliferation in
clinical material provides a potentially useful marker to estimate sensitivity
or resistance to anticancer drugs.
Cell proliferation is regulated by both
growth-stimulatory and growth-inhibitory proteins (Sherr, 1993). Protein
complexes that are composed of cyclins and cyclin-dependent kinases (cdks) are
important factors for cellular proliferation. Cyclins are regulatory proteins
for cdks and are differentially synthesized and degraded at specific points
during the cell cycle (Cordon-Cardo, 1995). Five major classes of mammalian
cyclins have been described (cyclin A-E). Cyclin C, D and E reach their peak of
synthesis and activity during the G1 phase and regulate the transition from G1
to S-phase. Cyclins A and B achieve their maximum peaks during S- and G2-phases.
We and others could demonstrate that cyclin A expression closely correlates
with the proportion of S-phase cells measured by flow cytometry (Volm et al,
1997). Furthermore, patients with cyclin A-positive lung carcinomas had
significantly shorter median survival times than patients with cyclin
A-negative carcinomas. A significant correlation between expression of cyclin A
and response of NSCLC to doxorubicin in vitro was also detected (Volm et al,
1997).
H. Hypoxia
Because the rate of neovascularization frequently
fails to keep pace with tumor growth, tumor vasculature is often inadequate for
the tumor mass. Therefore, many solid tumors contain subpopulations of cells
that are hypoxic and are relatively resistant to certain drugs (Teicher, 1994) and
irradiation (Hckel et al, 1993). This is partly caused to poor vascularization
that reduces the influx of cytostatic agents and lowers the levels of oxygen
and nutrients.
A growing body of evidence indicates that cells
respond to hypoxic stress by altering the expression of specific genes or
proteins (Wilson and Sutherland, 1989; Sutherland et al, 1996). Hypoxia is
known to induce one or more transcription factors, the best characterized of
which is hypoxia-inducible factor-1 (HIF-1), which in turn stimulates
expression of several genes including those involved in drug resistance and
endothelial cell growth. Hypoxia-induced resistance to doxorubicin and to
methotrexate has been attributed to an amplification of the P-glycoprotein gene
and the dihydrofolate reductase gene (Rice et al, 1986; 1987; Luk et et al,
1990; Kalra et al, 1993). Murphy et al, (1994) have recently shown that
metallothionein IIA mRNA levels were significantly increased during hypoxia and
during reoxygenation. OĠDwyer et al, (1994) investigated the effects of hypoxia
on the expression of a group of enzymes involved in drug metabolism. Exposing
colon carcinoma cells to hypoxia resulted in a notably increased glutathione
content.
In a clinical study with NSCLC, it has been shown that
poor vascularization, as measured by vessel density, correlates with an
upregulation of glutathione S-transferase-p, metallothionein and thymidylate synthase (Koomgi et al, 1995). In
another study involving rectal cancer, poor angiogenesis is also linked to an
expression of glutathione S-transferase and metallothionein (Mattern et al,
1996). Moreover, lung tumors with low microvessel density and low VEGF
expression were more frequently resistant to doxorubicin in vitro than tumors
with high microvessel density and high expression of VEGF (Volm et al, 1996).
These studies show that hypoxia or poor vascularization result in
overexpression of certain detoxicating enzymes which provides an additional
insight into cell resistance.
Some studies have demonstrated the presence of drug
resistance mechanisms in endothelial cells of normal and tumor tissue
(Cordon-Cardo et al, 1990; Terrier et al, 1990). The MDR-associated
P-glycoprotein and glutathione S-transferase have been localized in normal
human endothelial cells and in the stroma of some tumors. Furthermore, Huang
and Wright, (1994) found that some members of the fibroblast growth factor
family, which are potent angiogenic peptides, may mediate resistance to some
cytotoxic agents and modify gene amplification properties of tumor cells.
Furthermore, there is experimental evidence that tumor cells and vascular
endothelial cells within a solid tumor may stimulate each other by paracrine
factors (Rak and Kerbel, 1996). On the basis of these studies, it seems
reasonable to hypothesize that a highly vascularized tumor may produce elevated
levels of angiogenic peptides that induce proliferation of chemoresistant
endothelial cells which may confer tumor cell resistance to conventional
anticancer therapy.
I. Programmed cell death
The recent progress in the field of biology has
indicated that programmed cell death (apoptosis) plays an important role in the
chemotherapy-induced tumor cell killing. Since the different antineoplastic
agents induce a similar pattern of cell death, it was suggested that a common
pathway of apoptosis could exist in the drug-induced apoptosis and the defect
in the signaling pathway of apoptosis could cause a new form of multidrug
resistance in tumor cells. Recent studies in human leukemia cells have demonstrated
that chemosensitivity also depends on activation of caspases that are an
integral part of the CD95 signaling pathway (Los et al, 1997). Inhibition of
caspases not only retarded the apoptotic process but also provided protection
from drug-induced death. In a study with NSCLC, caspase-3 expression correlated
with a lower incidence of lymph node involvement and the median survival time
was longer for patients with caspase-3-positive tumors than for those with
caspase-3-negative tumors (Koomgi and Volm, 2000). Thus, impairment in the
protease effector phase of apoptosis may lead to chemoresistance against
several anticancer drugs that is not due to other well-characterized resistance
mechanisms such as overexpression of anti-apoptotic bcl-2-related proteins or
increased expression of P-gp (Friesen at al, 1997).
Overproduction of bcl-2, a blocker of apoptosis, prevents cell death induced by nearly most anticancer drugs and radiation, thus contributing to treatment failures in patients with cancer (Miyashita and Reed, 1993; Sartorius and Krammer, 2002). However, several homologs of bcl-2 have been discovered, some of which function as inhibitors of cell death and others as promoters of apoptosis that oppose the actions of the bcl-2 protein. Thus, the role of bcl-2 as a clinically significant prognostic factor of drug resistance remained open (Martin et al, 2003). In a study with 85 human squamous cell lung carcinomas, we found a positive correlation between expression of bcl-2 and expression of the resistance-related proteins P-gp and GST-p. Moreover, all bcl-2-positive carcinomas were resistant to doxorubicin in an in vitro predictive test (Volm and Mattern, 1995). These results indicate that bcl-2 may contribute to drug resistance in NSCLC.
IV. Co-expression of resistance
mechanisms and their putative regulation
During the past few years it has become apparent that
multiple mechanisms of resistance play a role in the clinical manifestaion of
drug resistance. The study of drug resistance in lung cancer has not identified
one single, specific mechanism as a major cause of the resistance observed in a
clinical setting. There are now various reports that cell populations exist in
human lung tumors which have several resistance mechanisms at once. The parallel
assessment of drug resistance parameters in human tumors has shown that
individual tumors exhibit different patterns: none, several or all of the
monitored resistance markers are elevated. This indicates that each tumor has
its own unique resistance factor profile. In lung tumors, Oberli-Schrmmli et
al, (1994) observed, in a majority of tumors, the concomitant overexpression of
ATase and GSH-related parameters. In contrast, overexpression of ATase together
with P-gp was never observed. There was no correlation between ATase and GSH or
its enzymes in colorectal tumors (Redmond et al, 1991), however, ATase was
frequently co-expressed with other drug resistance parameters in ovarain tumors
(Joncourt et al, 1998). An increased expression of P-gp was detected not only
concomitant to an overexpression of GST, but also accompanied by a coordinate
overexpression of metallothionein and thymidylate synthase in human lung tumor
(Volm and Mattern, 1992). A relationship exists between the extent of
resistance measured in vitro and the number of detected resistance mechanisms.
With an increasing extent of resistance, the number of resistance mechanisms
increases (Volm et al, 1992).
The reasons for the concomitant expression of
different resistant mechanisms in human lung tumors are unknown. The increased
expression of several resistance markers might be the result of induction of a
cascade of resistance-related gene products triggered by chemotherapy or
environmental factors. It was found from in vitro studies that NSCLC of smokers
are more frequently resistant and express a higher degree of P-gp and GST-p than tumors of non-smokers (Volm et al, 1991). Thus,
smoking may upregulate different detoxifying enzymes, depending on
histopathological and clinicopathological variables, to protect the cells from
carcinogens but as a consequence render them resistant to drugs. The coordinate
expression of different resistance mechanisms in the same tumor may explain why
tumors are also resistant to drugs not involved in therapy and why a single
marker, e.g. GST-p, may serve as a general
marker for resistance and prognosis, irrespective of whether it is itself
involved in the resistance mechanism (Mulder et al, 1995).
Another explanation for the presence of different
resistance mechanisms in human tumors is that tumors are mostly detected at a
relatively late stage when they are already large and have metastasized. These
tumors are for the most part hypoxic and the vascular network for supply of
oxygen and nutrients is substantially lower (Mattern et al, 1996). In fact, it
has been shown that various resistance parameters are upregulated in tumors
with poor vascularization (Koomgi et al, 1995) and that the reduced
vascularization of tumors together with upregulated resistance-related proteins
may represent an import contributing factor to the poor response to
chemotherapy and irradiation.
There are several hints that detoxifying systems may
share common regulatory elements. One possibility is that the resistance
factors present in human tumors belong to a set of genes that can be
coordinately expressed to protect cells from injury and against different
xenobiotics. Many oncogene products are implicated in the regulation of
cellular proliferation and, because the growth rate of tumors is an important
determinant for the response of tumors to chemotherapy, oncogenes might
influence drug resistance by regulation of proliferative activity.
It has been reported that c-fos is involved in growth
control and cellular differentiation (Verma, 1986). The c-fos protein is
associated with the gene product of the proto-oncogene c-jun. The c-fos/c-jun
protein complex binds specifically to a DNA sequence referred to as the AP-1
binding site and thereby affects the transcriptional expression of cellular
genes (Sassone-Corsi et al, 1988). It has been also demonstrated that the
promoter region of the Chinese hamster P-gp gene contains the AP-1 binding site
and that this latter is essential for full promoter activity (Teeter et al,
1991). The promoter region of the genomic GST-p also contains an AP-1 motif, which suggests that this
gene may be regulated by the cellular oncogenes c-fos and c-jun (Morrow et al,
1989). In a clinical study, surgical specimens of NSCLC of untreated patients
were analyzed for expression of c-fos, c-jun and for resistance to doxorubicin.
A significant association between drug resistance and expression of c-fos and
c-jun proteins was found (Volm, 1993). With a c-fos-transfected cell line it
was demonstrated that a ribozyme-mediated decrease in c-fos expression was
associated with reduced levels of thymidylate synthase, DNA polymerase b and metallothionein IIA (Scanlon et al, 1991). These
results suggest that Fos may mediate DNA replication and repair processes
through transcriptional activation of the aforementioned genes.
A recent study has shown that thymidylate synthase
protein binds to c-myc mRNA suggesting an involvement in the coordinate
regulation of a number of other genes (Chu et al, 1994). Whether the ATase gene
is a member of and co-regulated with other stress-responsive genes and
controlled by a common set of transcription factors remains to be elucidated.
V. Future directions
The recent development of DNA microarray technology
for large-scale analyses of gene expression has had a profound impact on
biomedical research. Microarrays allow the simultaneous analysis of thousands
of genes or proteins in a single experiment. Thus, it is not surprising that
the old concept of prediction of drug response and individualized therapy is
experiencing a revival. Staunton et al, (2001) determined whether the gene
expression signatures of untreated cells are sufficient for the prediction of
drug sensitivity. Using a panel of 60 human cancer cell lines, gene
expression-based classifiers of sensitivity or resistance of 232 compounds were
generated. They found that the accuracy of chemosensitivity prediction was
considerably better than would be expected by chance. Kudoh et al, (2000) used
the cDNA microarray to monitor the expression profiles of MCF-7 cells that are
selected for resistance to doxorubicin. They found that a subset of genes was
constitutively overexpressed in cells selected for resistance to doxorubicin.
Ikehara et al, (2004) conducted a study with 47 human lung tumors (using cDNA
microarray analysis) to determine whether expression levels of genes were
correlated with survival after chemotherapy. They analyzed the expression
levels of 1176 genes and found that three genes, G1/S-specific cyclin D2, type
II cGMP-dependent protein kinase and hepatocyte growth factor-like protein,
were significantly correlated with survival. Wigle et al, (2002) performed
expression profiling on tumor specimens from 39 NSCLC patients and could
identify distinct profiles of gene expression correlating with disease-free
survival.
Significant technological advances in protein
chemistry in the last decades have established mass spectrometry as a tool for
protein study. The recently developed ProteinChip technology using surface
enhanced laser desorption/ionisation (SELDI) mass spectrometry facilitate
protein profiling of complex biological mixtures and could be used to
discriminate e.g. normal vs. tumor tissues or treated vs. untreated cells.
Preliminary results with this technology show that this method could be used to
classify and predict histological subgroups as well as nodal involvement and
survival in resected NSCLC (Yanagisawa et al, 2003; Zhukov et al, 2003). The
promising aspect of all these new methods is the hope that it will be improve
the ability to identify those patients who are at high risk of failing therapy.
VI. Conclusions
The data obtained from multiple sources, including in vitro testing of lung tumors, determination of resistance-related enzymes and patient response indicate that no single, specific currently known drug resistance mechanism can explain the drug resistance and poor prognosis of patients with lung cancer. The mechanisms of resistance are numerous and depend on the detoxifying capacity of the cells, tissue-specific factors, repair capacity, drug delivery, cell proliferation and many others. Also mutations or amplification of specific genes involved in protective pathways or mutations of different oncogenes or suppressor genes may be responsible for the rsistance to chemotherapeutic drugs. Thus, the phenotype of resistance had to be understood as the net effect of a multifactorial process of a panel of resistance genes controlling an array of alternative resistance mechanisms (Stein, 2000). Consequently, clinical reversal of drug resistance may ultimately require intervention at several different sites in the tumor cell, ranging from blocking efflux pumps to inhibition of cytosolic detoxification enzymes and to inhibition of DNA repair. A key challenge for the future is to determine the relative quantitative contributions of each of these mechanisms to the drug-resistant phenotype. The recent development of DNA microarray technology for large-scale analysis of gene expression makes it possible to identify gene expression profiles in tumor cells which correlate with the treatment responsiveness such as drug resistance and clinical outcome of the disease. This could be of importance for better understanding of the biological behavior of the tumors and for better planning of treatment leading to a more rational, perhaps individualized choice of therapy.
References
Abe Y, Nakamura M, Ota E, Ozeki Y, Tamai S, Inooue H, Ueyama Y, Ogata
T, and Tamaoki N (1994) Expression
of the multidrug resistance gene (mdr1) in non-small cell lung cancer. Jpn J Cancer Res 85, 536-541.
Alama A, Constantini M, Repetto L, Conte PF, Serrano J, Nicolin A,
Barbieri F, Ardizzoni A, and Bruzzi P (1990)
Thymidin labelling index as prognostic factor in resected non-small cell
lung cancer. Eur J Cancer 26,
622-625.
Anttila S, Hirvonen A, Vainio H, Husgafvel-Pursiainen K, Hayes JD, and
Ketterer B (1993)
Immunohistochemical localization of glutathione S-transferases in human lung. Cancer Res 53, 5643-5648.
Arai T, Kuroishi T, Saito Y, Kurita Y, Naruke T, Kaneko M, and Japanese
Lung Cancer Screening Research Group (1994)
Tumor doubling time and prognosis in lung cancer patients: Evaluation from
chest films and clinical follow-up study. Jpn
J Clin Oncol 24, 199-204.
Awasthi YC, Singh SV, Ahmad H, and Moller PC (1987) Immunohistochemical evidence for the expression of GST1,
GST2, and GST3 gene loci for glutathione S-transferase in human lung. Lung 165, 323-332.
Berger W, Elbling L and Micksche M (2000)
Expression of the major vault protein LRP in human non-small cell lung cancer
cells: activation by short-term exposure to antineoplastic drugs. Int J Cancer 88, 293-300.
Borst P, Evers R, Kool M, and Wijnholds J (1999) The multidrug resistance protein family. Biochim Biophys Acta 1461, 347-357.
Bradley G, Juranka PF, and Ling V (1988)
Mechanisms of multidrug resistance. Biochim
Biophys Acta 948, 87-128.
Brent TP, Houghton PJ, and Houghton JA (1985) O6-alkyl -DNA methyltransferase activity correlates with the
therapeutic response of human rhabdomyosarcoma xenografts to 1-(2-chloroethyl)-3-(trans-4-methyl-cyclohexyl)-1-nitrosourea.
Proc Natl Acad Sci 82, 2985-2989.
Carmichael J, Mitchel JB, De Graff WG, Gamson J, Gazdar AF, Johnson BE,
Glatstein E, and Minna JD (1985)
Chemosensitivity testing of human lung cancer cell lines using the MTT assay. Br J Cancer 57, 540-547.
Carmichael J, Mitchell JB, Friedman N, Gazdar AF, and Russo A (1988) Glutathione and related enzyme
activity in human lung cancer cell lines. Br
J Cancer 58, 437-440.
Chin JL, Banerjee D, Kadhim SA, Kontozoglou TE, Chauvin PJ, and Cherian
MG (1993) Metallothionein in
testicular germ cell tumors and drug resistance. Cancer 72, 3029-3035.
Chu E, Voeller DM, Jones KL, Takechi T, Maley GF, Maley F, Segal S, and
Allegra CJ (1994) Identification of
a thymidylate synthase ribonucleoprotein complex in human colon cancer cells. Mol Cell Biol 14, 207-213.
Citron M, Decker R, Chen S, Schneider S, Graver M, Kleynerman L, Kahn
LB, White A, Schoenhaus M, and Yarosh D (1991)
O6-methylguanine-DNA methyltransferase in human normal and tumor tissue from
brain, lung, and ovary. Cancer Res
51, 4131-4134.
Citron M, Schoenhaus M, Graver M, Hoffman M, Lewis M, Wasserman P,
Niederland M, Kahn L, White A, and Yarosh D (1993) O6-methylguanine-DNA methyltransferase in human normal and
malignant lung tissue. Cancer Invest
11, 258-263.
Clapper ML, Hoffman SJ, Carp N, Watts P, Seestaller LM, Weese JL, and
Tew KD (1991) Contribution of
patient history to the glutathione S-transferase activity of human lung, breast
and colon tissue. Carcinogenesis 12,
1957-1961.
Cole SP, Chanda ER, Dicke FP, Gerlach JH, and Mirski SEL (1991) Non-P-glycoprotein-mediated
multidrug resistance in a small cell lung cancer cell line: Evidence for
decreased susceptibility to drug-induced DNA damage and reduced levels of
topoisomerase II. Cancer Res 51,
3345-3352.
Cole SPC, Bhardwaj G, Gerlach JH, Mackie JE, Grant CE, Almquist KC,
Stewart AJ, Kurz EU, Duncan AMV, and Deeley RG (1992) Overexpression of a transporter gene in a
multidrug-resistant human lung cancer cell line. Science 258, 1650-1654.
Cordon-Cardo C (1995) Mutation
of cell cycle regulators. Biological and clinical implications for human
neoplasia (review). Am J Pathol 147,
545-560.
Cordon-Cardo C, OĠBrien JP, Boccia J, Casals D, Bertino JR, and Melaned
MR (1990) Expression of the
multidrug resistance gene product (P-glycoprotein) in human normal and tumor
tissues. J Histochem Cytochem 38,
1277-1287.
DĠArpa P, and Liu LF (1989)
Topoisomerase-targeting antitumor drugs. Biochim
Biophys Acta 989, 163-177.
Di Ilio C, Del Boccio G, Aceto A, Casaccia R, Mucilli F, and Federici G
(1988) Elevation of glutathione
transferase activity in human lung tumor. Carcinogenesis
9, 335-340.
Dingemans ACM, Van Ark-Otte J, Van der Valk P, Apolinario RM, Scheper
RJ, Postmus PE, and Giaccone G (1996)
Expression of the human major vault protein LRP in human lung cancer samples
and normal lung tissues. Ann Oncol
7, 625-630.
Dingemans AM, Witlox MA, Stallaert RA, van der Valk P, Postmus PE, and
Giaccone G (1999) Expression of DNA
topoisomerase II alpha and topoisomerase II beta genes predicts survival and
response to chemotherapy in patients with small cell lung cancer. Clin Cancer Res 5, 2048-2058.
Dolan ME, Pegg AE, Moschel RC, and Grindey GB ( 1993) Effect of benzylguanine on the sensitivity of human colon
tumor xenografts to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Biochem Pharmacol 46, 285-290.
Drewinko B, Patchen M, Yang LY, and Barlogie B (1981) Differential killing efficacy of twenty antitumor drugs on
proliferating and nonproliferating human tumor cells. Cancer Res 41, 2328-2333.
Drin I, Schoket B, Kostic S, and Vincze I (1994) Smoking-related increase in O6-alkyl -DNA methyltransferase
activity in human lung tissue. Carcinogenesis
15, 1535-1539.
Eder JP, Chan VT-W, Ng S-W, Rizvi NA, Zacharoulis S, Teicher BA, and
Schnipper LE (1995) DNA
topoisomerase II a expression is associated with alkylating
agent resistance. Cancer Res 55,
6109-6116.
Eijdems EWHM, De Haas M, Timmermann AJ, Van der Schans GP, Kamst E, De
Nooji J, Astaldi-Ricotti GCB, Borst P, and Baas F (1985) Reduced topoisomerase I activity in multidrug-resistant
human non-small cell lung cancer cell lines. Br J Cancer 71, 40-47.
Fojo AT, Ueda K, Slamon DJ, Poplack DG, Gottesman MM, and Pastan I (1987) Expression of
multidrug-resistance gene in human tumors and tissues. Proc Natl Acad Sci 84, 265-269.
Friesen C, Fulda S, and Debatin KM (1997)
Deficient activation of the CD95 (APO-1/Fas) system in drug-resistant
cells. Leukemia 11, 1833-1841.
Giaccone G, Gazdar AF, Beck H, Zunino F, and Capranico G (1992) Multidrug sensitivity phenotype
of human lung cancer cells associated with topoisomerase II expression. Cancer Res 52, 1666-1674.
Goldstein LJ, Galski H, Fojo A, Willingham M, Lai SL, Gazdar A, Pirker
R, Green A, Crist W, Brodeur GM, Lieber M, Cossman J, Gottesman MM, and Pastan
I. J Natl Cancer Inst 81, 116-124.
Gros P, Neriah YB, Croop JM, and Housman DE (1986) Isolation and expression of a complementary DNA that confers
multidrug resistance. Nature 323,
728-731.
Hamburger AW, and Salmon SE (1977)
Primary bioassay of human tumor stem cells. Science 197, 461-463
Hamer DH (1986)
Metallothionein. Annu Rev Biochem
55, 913-951.
Hart BA, Voss GW, and Vacek PM (1993)
Metallothionein in human lung carcinoma. Cancer
Lett 75, 121-128.
Haugen H (2000) Etiology of
lung cancer. In: Hansen HH, ed. Textbook of lung cancer. London: Martin Dunitz,
pp. 1-12.
Herzog CE, Trepel JB, Mickley LA, Bates SE, and Fojo AT (1992) Various methods of analysis of
mdr1/P-glycoprotein in human colon cancer cell lines. J Natl Cancer Inst 84, 711-716.
Hckel M, Vorndran B, Schlenger K, Baussmann E, and Knapstein PG (1993) Tumor oxygenation: a new
predictive parameter in locally advanced cancer of the uterine cervix. Gynecol Oncol 51, 141-149.
Huang A, and Wright JA (1994)
Fibroblast growth factor mediated alterations in drug resistance and evidence
of gene amplification. Oncogene 9,
491-499.
Huang CL, Yokomise H, Kobayashi S, Fukushima M, Hitomi S, and Wada H (2000) Intratumoral expression of
thymidylate synthase and dihydropyrimidine dehydrogenase in non-small cell lung
cancer patients treated with 5-FU-based chemotherapy. Int J Oncol 17, 47-54.
Ikehara M, Oshita F, Sekiyama A, Hamanaka N, Saito H, Yamada K, Noda K,
Kameda Y, and Miyagi Y (2004)
Genome-wide cDNA microarray screening to correlate gene expression profile with
survival in patients with advanced lung cancer. Oncol Rep 11, 1041-1044.
Ishikawa T, Kuo MT, Furuta K and Suzuki M (2000) The human multidrug resistance-associated protein (MRP) gene
family: from biological function to drug molecular design. Clin Chem Lab Med 38, 893-897.
Joncourt F, Buser K, Altermatt HJ, Bacchi M, Oberli A, and Cerny T (1998) Multiple drug resistance
parameter expression in ovarian cancer. Gynecol
Oncol 70, 176-182.
Joseph MG, Banerjee D, Kocha W, Feld R, Stitt LW, and Cherian MG (2001) Metallothionein expression in
patients with small cell carcinoma of the lung: correlation with other
molecular markers and clinical outcome. Cancer
92, 836-842.
Kaina B, Fritz G, Mitra S, and Coquerelle T (1991) Transfection and expression of human O6-methylguanine-DNA
methyltransferase (MGMT) cDNA in Chinese hamster cells: The role of MGMT in
protection against the genotoxic effects of alkylating agents. Carcinogenesis 12, 1857-1867.
Kakolyris S, Giatromanolaki A, Koukourakis M, Powis G, Souglakos J,
Sivridis E, Georgoulias V, Gatter KC, and Harris AL (2001) Thioredoxin expression is associated with lymph node status
and prognosis in early operable non-small cell lung cancer. Clin Cancer Res 7, 3087-3091.
Kalra R, Jones AM, Kirk J, Adams GE, and Stratford IJ (1993) The effect of hypoxia on
acquired drug resistance and response to epidermal growth factor in Chinese
hamster lung fibroblasts and human breast-cancer cells in vitro. Int J Cancer 54, 650-655.
Kasahara K, Fujiwara Y, Nishio K, Ohmori T, Sugimoto Y, Komiya K,
Matsuda T, and Saijo N (1991)
Metallothionein content correlates with the sensitivity of human small cell
lung cancer cell lines to cisplatin. Cancer
Res 51, 3237-3242.
Kasahara K, Fujiwara Y, Sugimoto Y, Nishio K, Tamura T, Matsuda T, and
Saijo N (1992) Determinants of
response to the DNA topoisomerase II inhibitors doxorubicin and etoposide in
human lung cancer cell lines. Cancer Res
84, 113-118.
Kelley SL, Basu A, Teicher BA, Hacker MP, Hamer DH, and Lazo JS (1988) Overexpression of
metallothionein confers resistance to anticancer drugs. Science 241, 1813-1815.
Kinnula VL, Paakko P, and Soini Y (2004)
Antioxidant enzymes and redox regulating thiol proteins in malignancies of
human lung. FEBS Lett 569, 1-6.
Koomgi R, and Volm M (2000)
Relationship between the expression of caspase-3 and the clinical outcome of
patients with non-small cell lung cancer. Anticancer
Res 20, 493-496.
Koomgi R, Mattern J, and Volm M (1995)
Up-regulation of resistance-related proteins in human lung tumors with poor
vascularization. Carcinogenesis 16,
2129-2133.
Kudoh K, Ramanna M, Ravatn R, Elkahloun AG, Bittner ML, Meltzer PS,
Trent JM, Dalton WS, and Chin KV (2000)
Monitoring the expression profiles of doxorubicin-induced and
doxorubicin-resistant cancer cells by cDNA microarray. Cancer Res 60, 4161-4166.
Lai SL, Goldstein LJ, Gottesman MM, Pastan I, Tsai CM, Johnson BE,
Mulshine JL, Ihde DC, Kayser K, and Gazdar A (1989) MDR1 gene expression in lung cancer. J Natl Cancer Inst 81, 1144-1150.
Lehtonen ST, Svensk AM, Soini Y, Paakko P, Hirvikoski P, Kang SW, Saily
M, and Kinnula VL (2004)
Peroxiredoxins, a novel protein family in lung cancer. Int J Cancer 111, 514-521.
Linsenmeyer ME, Jefferson W, Wolf M, Matthews JP, Board PG, and
Woodcock DM (1992) Levels of
expression of the mdr1 gene and glutathione S-transferase genes 2 and 3 and
response to chemotherapy in multiple myoloma. Br J Cancer 65, 471-475.
Los M, Herr I, Friesen C, Fulda S, Schulze-Osthoff K, and Debatin KM (1997) Cross-resistance of CD95- and
drug-induced apoptosis as a consequence of deficient activation of caspases
(ICE/Ced-3 proteases). Blood 90,
3118-3129.
Luk CK, Veinot-Drebot L, Tjan E, and Tannock IF (1990) Effect of transient hypoxia on sensitivity to doxorubicin in
human and murine cell lines. J Natl
Cancer Inst 82, 684-692.
Martin B, Paesmans M, Berghmans T, Branle F, Ghisdal L, Mascaux C,
Meert A-P, Steels E, Vallot F, Verdebout J-M, Lafitte J-J, and Sculier J-P (2003) Role of bcl-2 as a prognostic
factor for survival in lung cancer: a systematic review of the literature with
meta-analysis. Br J Cancer 89,
55-64.
Matsumoto Y, Oka M, Sakamoto A, Narasaki F, Fukuda M, Takatani H,
Terashi K, Ikeda K, Tsurutani J, Nagashima S, Soda H, and Kohno S (1997) Enhanced expression of
metallothionein in human non-small cell lung carcinomas following chemotherapy.
Anticancer Res 17, 3777-3780.
Mattern J, and Volm M (1982)
Clinical relevance of predictive tests for cancer chemotherapy. Cancer Treat Rev 9, 267-298.
Mattern J, and Volm M (1992)
Increased resistance to doxorubicin in human non-small cell lung carcinomas
with metallothionein expression. Int J
Oncol 1, 687-689.
Mattern J, Bak M, and Volm M (1987)
Occurrence of a multidrug-resistant phenotype in human lung xenografts. Br J Cancer 56, 407-411.
Mattern J, Bak M, Hahn EW, and Volm M (1988) Human tumor xenografts as model for drug testing. Cancer Metastasis Rev 7, 263-284.
Mattern J, Kallinowski F, Herfarth C, and Volm M (1996) Association of resistance-related protein expression with
poor vascularization and low levels of oxygen in human rectal cancer. Int J Cancer 67, 20-23.
Mattern J, Wayss K, and Volm M (1984)
Effect of five antineoplastic agents on tumor xenografts with different growth
rates. J Natl Cancer Inst 72,
1335-1339.
Mattern J, Koomgi R, and Volm M (1999)
Smoking-related increase of O6-methylguanine-DNA methyltransferase expression
in human lung carcinomas. Carcinogenesis
19, 1247-1250.
Mattern J, Koomgi R, and Volm M (2002)
Characteristics of long-term survivors of untreated lung cancer. Lung Cancer 36, 277-282.
McLeod HL, Douglas F, Oates M, Symond RP, Prakash D, Van der Zee AGJ,
Kaye SB, Brown R, and Keith WN (1994)
Topoisomerase I and II activity in human breast, cervix, lung and colon cancer.
Int J Cancer 59, 607-611.
Morrow CS, Cowan KH, and Goldsmith ME (1989) Structure of the human genomic glutathione S-transferase p gene. Gene 75, 3-11.
Muggia FM (1974) Cell
kinetic studies in patients with lung cancer. Oncology 30, 353-361.
Mulder TPJ, Verspaget HW, Sier CFM, Roelof HMJ, Ganesh S, Griffioen G,
and Peters WHM (1995) Glutathione
S-transferase p in colorectal tumors is predictive for
overall survival. Cancer Res 55,
2696-2702.
Murphy BJ, Laderoute KR, Chin RJ, and Sutherland RM (1994) Metallothionein IIA is
up-regulated by hypoxia in human A431 squamous carcinoma cells. Cancer Res 54, 5808-5810.
Murphy D, McGown AT, Crowther D, Mander A, and Fox BW (1991) Metallothionein levels in
ovarian tumours before and after chemotherapy. Br J Cancer 63, 711-714.
Miyashita T, and Reed JC (1993)
Bcl-2 oncoprotein blocks chemotherapy-induced apoptosis in a human leukemia
cell line. Blood 81, 151-157.
Nakagawa K, Saijo N, Tsuchidas S, Sakai M, Tsunokawa Y, Yokota J,
Muramatsu M, Sato K, Tereda M, and Tew KD (1990)
Glutathione S-transferase-p as a determinant of drug
resistance in transfectant cell lines. J
Biol Chem 265, 4296-4301.
Nakagawa T, Otake Y, Yanagihara K, Miyahara R, Ishikawa S, Fukushima M,
Wada H, and Tanaka F (2004)
Expression of thymidylate synthase is correlated with proliferative activity in
non-small cell lung cancer (NSCLC). Lung
Cancer 43, 145-149.
Nooter K, Bosman FT, Burger H, Van Wingerden KE, Flens MJ, Scheper RJ,
Oostrum RG, Boersma AWM, Van der Gaast A, and Stoter G (1996) Expression of the multidrug resistance associated protein
(MRP) gene in primary non-small cell lung cancer. Ann Oncol 7, 75-81.
OĠDwyer PJ, Yao KS, Ford P, Godwin AK, and Clayton M (1994) Effects of hypoxia on
detoxicating enzyme activity and expression in HT29 colon adenocarcinoma cells.
Cancer Res 54, 3082-3087.
Oberli-Schrmmli AE, Joncourt F, Stadler M, Altermatt HJ, Buser K, Ris
HB, Schmid U, and Cerny T (1994)
Parallel assessment of glutathione-based detoxifying enzymes, O6-alkyl -DNA
methyltransferase and P-glycoprotein as indicators of drug resistance in tumor
and normal lung of patients with lung cancer. Int J Cancer 59, 629-636.
fner D, Maier H, Riedmann B, Bammer T, Rumer A, Winde G, Bcker W,
Jasan B, and Schmid KW (1994)
Immunohistochemical metallothionein expression in colorectal adenocarcinoma:
Correlation with tumour stage and patient survival. Virchows Arch 425, 491-497.
Ota E, Abe Y, Oshika Y, Ozeki Y, Iwasaki M, Inoue H, Yamazaki H, Ueyama
Y, Takagi K, and Ogata T (1995)
Expression of the multidrug resistance-associated protein (MRP) gene in
non-small cell lung cancer. Br J Cancer
72, 550-554.
Pu QQ, and Bezwoda WR (1999)
Induction of alkylator (melphalan) resistance in HL60 cells is accompanied by
increased levels of topoisomerase II expression and function. Mol Pharmacol 56, 147-153.
Radosevich JA, Robinson PG, Rittmann-Grauer LS, Wilson B, Leung JP,
Maminta ML, Warren W, Rosen S, and Gould VE (1989) Immunohistochemical analysis of pulmonary and pleural tumors
with the monoclonal antibody HYB-612 directed against the multidrug resistance
(MDR-1) gene product, P-glycoprotein. Tumor
Biol 10, 252-257.
Rak JW, and Kerbel RS (1996)
Reciprocal paracrine interactions between tumor cells and endothelial cells:
The âangiogenesis progressionÔ hypothesis. Eur
J Cancer 32A, 2438-2450.
Redmond SMS, Joncourt F, Buser K, Ziemiecki A, Altermatt HJ, Fey M,
Margison G, and Cerny T (1991)
Assessment of P-glycoprotein, glutathione-based detoxifying enzymes and
O6-alkylguanine-DNA alkyltransferase as potential indicators of constitutive
drug resistance in human colorectal tumors. Cancer Res 51, 2092-2097.
Rice GC, Hoy C, and Schimke RT (1986)
Transient hypoxia enhances the frequency of dihydrofolate reductase gene
amplification in Chinese hamster ovary cells. Proc Natl Acad Sci 83, 5978-5982.
Rice GC, Ling V, and Schimke RT (1987)
Frequencies of independent and simultaneous selection of Chinese hamster cells
for methotrexate and doxorubicin (adriamycin) resistance. Proc Natl Acad Sci 84, 9261-9264.
Richardson GE, and Johnson BE (1993)
The biology of lung cancer. Semin Oncol
20, 105-127.
Ruckdeschel JC, Carney DN, Oie HK, Russel EK, and Gazdar AF (1987) In vitro chemosensitivity of
human lung cancer cell lines. Cancer
Treat Rep 71, 697-704.
Sartorius UA, and Krammer PH (2002)
Upregulation of bcl-2 is involved in the mediation of chemotherapy resistance
in human small cell lung cancer cell lines. Int J Cancer 97, 584-592.
Sassone-Corsi P, Lamph HW, Kamps M, and Verma IM (1988) Fos-associated cellular p39 is related to nuclear transcription
factor AP-1. Cell 54, 553-563.
Scanlon KJ, Jiao L, Wang W, Tone T, Rossi JJ, and Kashani-Sabet M (1991) Ribozyme-mediated cleavage of
c-fos mRNA reduces gene expression of DNA synthesis enzymes and
metallothionein. Proc Natl Acad Sci
88, 10591-10595.
Scheper RJ, Broxtermann HJ, Scheffer GL, Kaaijk P, Dalton WS, Van
Heijningen THM, Van Kalken CK, Slovak ML, De Vries EGE, Van der Kalk P, Meijer
CJLM, and Pinedo HM (1993)
Overexpression of a Mr 110,000 vesicular protein in non-P-glycoprotein-mediated
multidrug resistance. Cancer Res 53,
1475-1479.
Sharma R, Singhal SS, Srivastava SK, Bajpai KK, Frenkel EP, and Awasthi
S (1993) Glutathione and glutathione
linked enzymes in human small cell lung cancer cell lines. Cancer Lett 75, 111-119.
Sherr CJ (1993) Mammalian G1
cyclins. Cell 73, 1059-1065.
Shin HJC, Lee JS, Hong WK, and Shin DM (1992) Study of multidrug resistance (mdr1) gene in non-small cell
lung cancer. Anticancer Res 12,
367-370.
Shintani Y, Ohta M, Hirabayashi H, Tanaka H, Iuchi K, Nakagawa K, Maeda
H, Kido T, Miyoshi S, and Matsuda H (2004)
Thymidylate synthase and dihydropyrimidine dehydrogenase mRNA levels in tumor
tissues and the efficacy of 5-fluorouracil in patients with non-small cell lung
cancer. Lung Cancer 45, 189-196.
Soini Y, Kahlos K, Napankangas U, Kaarteenaho-Wiik R, Saily M,
Koistinen P, Paakko P, Holmgren A, and Kinnula VL (2001) Widespread expression of thioredoxin and thioredoxin
reductase in non-small cell lung carcinoma. Clin Cancer Res 7, 1750-1757.
Staunton JE, Slonim DK, Coller HA, Tamayo P, Angelo MJ, Park J, Scherf
U, Lee JK, Reinhold WO, Weinstein JN, Mesirov JP, Lander ES, and Golub TR (2001) Chemosensitivity prediction by
transcriptional profiling. Proc Natl
Acad Sci 98, 10787-10792.
Stein US (2000)
P-glycoprotein turned twenty: are we any closer to fight drug resistance in
cancer? Onkologie 23, 316-317.
Sutherland RM, Ausserer WA, Murphy BJ, and Laderoute KR (1996) Tumor hypoxia and heterogeneity:
challenges and opportunities for the future. Sem Radiat Oncol 6, 59-70.
Teeter LD, Eckersberg T, Tsai Y, and Kuo MT (1991) Analysis of the Chinese hamster P-glycoprotein/multidrug
resistance gene pgp1 reveals that the AP-1 site is essential for full promoter
activity. Cell Growth Differ 2,
429-437.
Teicher BA (1994) Hypoxia
and drug resistance. Cancer Metastasis
Rev 13, 139-168.
Terrier P, Townsend AJ, Coindre JM, Triche TJ, and Cowan KM (1990) An immuno-histochemical study of
Pi class glutathione S-transferase expression in normal human tissues. Am J Pathol 137, 845-853.
Tew KD (1994)
Glutathione-associated enzymes in anticancer drug resistance. Cancer Res 54, 4313-4320.
Twentyman PR, Fox NE, Wright KA, and Bleehen NM (1986) Derivation and preliminary characterisation of Adriamycin
resistant cell lines of human lung cancer cells. Br J Cancer 53, 529-537.
Valeriote F, and Van Putten L (1975)
Proliferation-dependent cytotoxicity of anticancer agents: A review. Cancer Res 3, 2619-2630.
Van der Kolk DM, Vellenga E, Muller M and de Vries EG (1999) Multidrug resistance protein
MRP1, glutathione, and related enzymes. Their importance in acute myeloid
leukemia. Adv Exp Med Biol 457,
187-198.
Verma IM (1986) Protooncogene
fos: a multifaceted gene. Trends Genet
2, 93-96.
Volm M (1993) P-glycoprotein
associated expression of c-fos and c-jun products in human lung carcinomas. Anticancer Res 13, 375-378.
Volm M, and Mattern J (1992a)
Elevated expression of thymidylate synthase in doxorubicin resistant non-small
cell lung carcinomas. Anticancer Res
12, 2293-2296.
Volm M, and Mattern J (1992b)
Expression of topoisomerase II, catalase, metallothionein and thymidylate
synthase in human squamous cell lung carcinomas and their correlation with
doxorubicin resistance and with patientsÔ smoking habits. Carcinogenesis 13, 1947-1950.
Volm M, and Mattern J (1995)
Increased expression of bcl-2 in drug-resistant squamous cell lung carcinomas. Int J Oncol 7, 1333-1338.
Volm M, Wayss K, Kaufmann M, and Mattern J (1979) Pretherapeutic detection of tumor resistance and the results
of tumor chemotherapy. Eur J Cancer
15, 983-993.
Volm M, Hahn EW, Mattern J, Mller T, Vogt-Schaden I, and Weber E (1988) Five-year follow-up study of
independent clinical and flow cytometric prognostic factors for the survival of
patients with non-small cell lung carcinoma. Cancer Res 48, 2923-2928.
Volm M, Hecker S, Sauerbrey A, and Mattern J (1995a) Predictive value of statin, a Go-associated cell cycle
protein, in childhood acute lymphoblastic leukemia. Int J Cancer (Pred Oncol) 64, 166-170.
Volm M, Koomgi R, and Mattern J (1995b)
Prognostic significance of proliferating cell nuclear antigen (PCNA) in
adenocarcinoma of the lung. Int J Oncol
6, 359-362.
Volm M, Koomgi R, and Mattern J (1996)
Interrelationship between microvessel density, expression of VEGF and
resistance to doxorubicin in non-small cell lung carcinoma. Anticancer Res 16, 213-218.
Volm M, Koomgi R, Mattern J, and Stammler G (1997) Cyclin A is associated with an unfavourable outcome in
patients with non-small cell lung carcinomas. Br J Cancer 75, 1774-1778.
Volm M, Mattern J, and Samsel B (1991)
Overexpression of P-glycoprotein and glutathione S-transferase-p in resistant non-small cell
lung carcinomas of smokers. Br J Cancer
64, 700-704.
Volm M, Mattern J, Efferth T, and Pommerenke EW (1992) Expression of several resistance mechanisms in untreated
human kidney and lung carcinomas. Anticancer
Res 12, 1063-1068.
Volm M, Mattern J, Sonka J, Vogt-Schaden M, and Wayss K (1985) DNA distribution in non-small
cell lung carcinomas and ist relationship to clinical behavior. Cytometry 6, 348-356.
Weisenthal LM, Marsden JA, Dill PL, and Macaluso CK (1983) A novel dye exclusion method for
testing in vitro chemosensitivity of human tumors. Cancer Res 43, 749-757
Whelan RDH, Hosking LK, Townsend AJ, Cowan KH, and Hill BT (1989) Differential increases in
glutathione S-transferase activities in a range of multidrug-resistant human
tumor cell lines. Cancer Commun 1,
359-365.
Wigle DA, Jurisica I, Radulovich N, Pintilie M, Rossant J, Liu N, Lu C,
Woodgett J, Seiden I, Johnston M, Keshavjee S, Darling G, Winton T, Breitkreutz
BJ, Jorgenson P, Tyers M, Shepherd FA, and Tsao MS (2002) Molecular profiling of non-small cell lung cancer and
correlation with disease-free survival. Cancer
Res 62, 3005-3008.
Wilson RE, and Sutherland RM (1989)
Enhanced synthesis of specific proteins, RNA and DNA caused by hypoxia and
reoxygenation. Int J Radiat Oncol Biol
Phys 16, 957-961.
Yanagisawa K, Shyr Y, Xu BJ, Massion PP, Larsen PH, White BC, Roberts
JR, Edgerton M, Gonzalez A, Nadaf S, Moore JH, Caprioli RM, and Carbone DP (2003) Proteomic patterns of tumour
subsets in non-small cell lung cancer. The
Lancet 362, 433-439.
Yoshida M, Suzuki T, Komiya T, Hatashita E, Nishio K, Kazuhiko N, and
Fukuoka M (2001) Induction of MRP5
and SMRP mRNA by adriamycin exposure and its overexpression in human lung
cancer cells resistant to adriamycin. Int
J Cancer 94, 432-437.
Zijlstra JG, De Jongs S, De Vries EGE, and Mulder NH (1990) Topoisomerases, new targets in
cancer chemotherapy. Med Oncol Tumor
Pharmacother 7, 11-18.
Zhukov TA, Johanson RA, Cantor AB, Clark RA, and Tockman MS (2003) Discovery of distinct protein
profiles specific for lung tumors and pre-malignant lung lesions by SELDI mass
spectrometry. Lung Cancer 40,
267-279.
Dr. Jrgen Mattern