Co-transfection of MRP and bcl-2 antisense S-oligodeoxynucleotides reduces drug resistance in cisplatin-resistant lung cancer cells.
OBJECTIVE
To detect the influence of antisense s-oligodeoxynucleotides (S-ODNs) of bd-2 and multidrug resistance-associated protein (MRP) genes multidrug resistance-associated protein gene and bcl-2 antisense S-oligodeoxynucleotides on cisplatin-resistant lung adenocarcinoma cell line A549DDP which overexpresses both bcl-2 and MRP.


METHODS
A549DDP cells were treated with sense and antisense S-ODN mediated by lipofection. Expression of MRP and bcl-2 mRNA and protein in the treated cells was measured by RT-PCR and flow cytometry (FCM), respectively. Apoptosis was identified by DNA electrophoresis and terminal deoxynucleotidyl transferase (TdT)-mediated biotin dUTP nick end-labeling (TUNEL). The degree of drug resistance of the treated cells was detected by a cell viability 3'-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyl-tefrazolium bromide thiazolylblue (MTT) assay.


RESULTS
Expression of bcl-2 and MRP significantly decreased in the cells treated with bcl-2 or/and MRP antisense S-ODN for 48 h as compared to the cells untreated and sense-treated (P < 0.05). Resistance to cisplatin in the cells treated with bcl-2 or/and MRP antisense S-ODN decreased by 60.6% (6.5 times), 56.4% (7.2 times) and 71.0% (4.8 times), respectively, which paralleled the decrease of bcl-2 and MRP expression. Similarly, the resistance to etoposide and epirubicin in antisense-treated cells also reduced in parallel to decreases of the two gene expressions. The drug resistance in sense-treated cells was similar to that in untreated cells. Statistically significant dose- and concentration-dependent increases of apoptotic cells were observed in the groups exposed to 100 mumol/L cisplatin for 48 h after treatment by bcl-2 or/and MRP antisense.


CONCLUSIONS
Bcl-2 and MRP were at least additive and possibly synergistic in conferring drug resistance in a cisplatin-resistant lung adenocarcinoma cell line. Antisense S-ODN could attenuate drug resistance by promoting cells apoptosis, which might lead to a new treatment for patients with non-small cell lung cancers (NSCLCs) who are refractory to conventional chemotherapy.
Wang
J
J
Department of Internal Medicine, School of Oncology, Beijing Medical University, Beijing 100036, China. Wangjie_CC@yahoo.com
Liu
X
X
Jiang
W
W
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D019254:Genes, bcl-2 / Q000502:physiology*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000473:pathology; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000502:physiology*; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology*; D013873:Thionucleotides / Q000494:pharmacology*; D014162:Transfection
D000970:Antineoplastic Agents; D002945:Cisplatin; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D013873:Thionucleotides