Cisplatin sensitivity/resistance in UV repair-deficient Chinese hamster ovary cells of complementation groups 1 and 3

Abstract

We assessed the possible role of the human repair genes, ERCC1 and ERCC3, in resistance to cisplatin-induced cytotoxicity. The UV repair-deficient Chinese hamster ovary (CHO) 43:3B [designated ERCC1(-)] cell line and its paired subline 83-J5, which is stably transfected with the human DNA excision repair gene ERCC1 [designated ERCC1(+)], were used in this study. UV repair-deficient CHO 27-1 cells [designated ERCC3(-)] and its paired subline designated 'ERCC3(+)', which is stably transfected with the human DNA excision repair gene ERCC3, were also used. In each pair of cell lines, we assessed cisplatin cytotoxicity, cellular drug accumulation and platinum-DNA adduct repair after 1 h drug exposures. Drug accumulation and DNA repair were assessed by atomic absorption spectrometry with Zeeman background correction. ERCC1(+) cells (IC50 = 4.0 microM) were 5-fold more resistant to cisplatin than ERCC1(-) cells (IC50 = 0.75 microM). ERCC1(+) cells repaired 25% of DNA lesions in cellular DNA within a 6 h time period following an IC50 drug exposure and repaired 48% over 24 h. No DNA repair was observed in ERCC1(-) cells during the same time periods. Both cell lines showed similar patterns of drug accumulation. For ERCC3(-) cells (IC50 = 54 microM) and ERCC3(+) cells (IC50 = 49 microM), the profiles of cisplatin sensitivity and cellular drug accumulation were similar. When treated with 50 microM cisplatin, these cells showed similar patterns of drug accumulation, and were equally efficient at forming and repairing lesions in cellular DNA. These data show that in UV repair-deficient CHO cells, ERCC1 confers resistance to cisplatin and confers the ability to remove platinum from cellular DNA. In contrast, ERCC3 does not influence cisplatin drug sensitivity or adduct repair capability. This suggests that ERCC1 may be a determinant of cisplatin resistance, whereas ERCC3 is probably not.

Combined modalities of resistance in an oxaliplatin-resistant human gastric cancer cell line with enhanced sensitivity to 5-fluorouracil

“…Excision repair cross complementation-1 plays a pivotal role in NER pathway, influencing the repair of platinum/ DNA damage because of its adducts recognition and excision ability (Lee et al, 1993). It has been indicated that subjects with lower ERCC-1 levels had lower DNA repair capacity (Rosell et al, 2003).…”

Cisplatin: mode of cytotoxic action and molecular basis of resistance

“…Although the NER complex is composed of at least 17 different proteins (Sancar, 1994;Friedberg, 2001), it appears that upregulation of only a few rate-limiting proteins is necessary to increase the excision repair capacity in resistant tumor cells (Reed, 1998). For instance, cisplatin resistance is associated with increases in the excision repair crosscomplementing ERCC1 or ERCC1/ XPF complexes, but not ERCC3 (Lee et al, 1993;Ferry et al, 2000). This finding with ERCC1 is of clinical relevance, as a twofold increase in ERCC1 mRNA levels has been noted in patient's tumors that have become insensitive to cisplatin (Dabholkar et al, 1994).…”

cis -Diammine(pyridine)chloroplatinum(II), a monofunctional platinum(II) antitumor agent: Uptake, structure, function, and prospects

“…A test for the presence of a key protein in the excision repair pathway, ERCC1, is in FDA Phase III trials for use as a predictive factor in tailoring chemotherapy to patients with nonsmall cell lung cancer (28). Conversely, increased efficiency of excision repair leads to rapid removal of cisplatin adducts and is associated with cisplatin resistance in human tumor cells (29,30). We used 156-mer DNA probes (Figs.…”