The determinants of sensitivity and acquired resistance to gemcitabine differ in non–small cell lung cancer: a role of ABCC5 in gemcitabine sensitivity

Abstract

We examined the expression levels of the multidrug resistance protein 5 (ABCC5) gene in non -small cell lung cancer (NSCLC) cell lines to clarify the relationship with the sensitivity to gemcitabine. The expression levels of ABCC5 were inversely correlated with gemcitabine sensitivity significantly (r = 0.628; P < 0.01) in 17 NSCLC cells, whereas the expression of ABCC5 in the gemcitabine-resistant NSCLC cell line H23/GEM-R was the same as that in parental NCI-H23 cells. Treatment with the ABCC5 inhibitor zaprinast altered the sensitivity to gemcitabine in ABCC5-expressing NSCLC cells. In addition, decreasing the expression of ABCC5 by small interfering RNA altered the cytotoxicity to gemcitabine. These results indicate that modulation of ABCC5 activity could be used to increase the gemcitabine sensitivity in NSCLC. Previously, we found a decreased expression of deoxycytidine kinase in H23/GEM-R cells, and further investigation in this study showed an increased expression of ribonucleotide reductase subunit 1 in H23/GEM-R cells. We therefore also examined the effect of modifying the expression of both genes on gemcitabine resistance. We found that using small interfering RNA to decrease the expression of ribonucleotide reductase subunit 1 resulted in a decreased resistance to gemcitabine in H23/GEM-R cells. Furthermore, pretreatment with pemetrexed resulted in an increased deoxycytidine kinase expression concomitant with the alteration of the resistance to gemcitabine in H23/GEM-R cells. The determinants for sensitivity and the acquired resistance in gemcitabine are quite different; nonetheless, modification of these factors may increase the efficacy of gemcitabine in the treatment of NSCLC.

Silencing of ribonucleotide reductase subunit M1 potentiates the antitumor activity of gemcitabine in resistant cancer cells

“…Moreover, Fan et al (1997) reported that chemosensitivity of gemcitabine resistant cancer cells, and previous in vitro data, including ours, confirmed that the downregulation of the expression of RRM1 could restore the sensitivity of gemcitabine resistant cancer cells to gemcitabine. 10,11,13,14,17,21 However, to our best knowledge, the feasibility of enhancing the chemosensitivity of cancer cells to gemcitabine using RRM1-specific siRNA has not yet been tested in an animal model.…”

“…4,5 RRM1 has been identified as the key molecule in determining the efficacy of gemcitabine. The overexpression of RRM1 had been repeatedly reported in gemcitabine-resistant cancer cells both in vitro and in vivo, [6][7][8][9][10][11] and RRM1 overexpression through the transfection of a lung cancer cell line led to gemcitabine resistance as well. 9 …”

“…19,20 Previously, we and others have shown that the downregulation of RRM1 expression using small interfering RNA (siRNA) increased the sensitivity of gemcitabine resistant cancer cells to gemcitabine in vitro. 10,11,13,14,17,21 In the present study, we tested the feasibility of using RRM1-specific siRNA to downregulate RRM1 expression and thus sensitize RRM1-overexpressing tumor cells to gemcitabine in an animal model. In vivo siRNA delivery remains challenging due to the poor stability of unmodified siRNA molecules and the difficulty in delivering them intracellularly.…”

MRP8/ABCC11 directly confers resistance to 5-fluorouracil

“…Modification of 5-FUCytotoxicity by RNA Interference Approximately 2 Â 10 5 cells were transfected with small interfering RNA (siRNA) oligonucleotide using Lipofectamine TM 2000 (Invitrogen) to produce a final RNA concentration of 50 nmol/L in serum-free Opti-MEM medium (Invitrogen) as described previously (19). At 24 h after transfection, we changed the medium to RPMI 1640 supplemented with 10% heat-inactivated FBS.…”

Expression of gemcitabine- and cisplatin-related genes in non-small-cell lung cancer

“…These results are in agreement with previous studies showing increased sensitivity to gemcitabine after siRNA against RRM1 in pancreatic and lung cancer cell lines. 44,45 In contrast, the hENT1-targeting siRNA did not affect gemcitabine sensitivity in pancreatic cancer cells, 44 suggesting different sensitivity in different cell lines.…”