Claudin-3 and claudin-4 regulate sensitivity to cisplatin by controlling expression of the copper and cisplatin influx transporter CTR1.
Claudin-3 (CLDN3) and claudin-4 (CLDN4) are the major structural molecules that form tight junctions (TJs) between epithelial cells. We found that knockdown of the expression of either CLDN3 or CLDN4 produced marked changes in the phenotype of ovarian cancer cells, including an increase in resistance to cisplatin (cDDP). The effect of CLND3 and CLDN4 on cDDP cytotoxicity, cDDP cellular accumulation, and DNA adduct formation was compared in the CLDN3- and CLDN4-expressing parental human ovarian carcinoma 2008 cells and CLDN3 and CLDN4 knockdown sublines (CLDN3KD and CLDN4KD, respectively). Knockdown of CLDN3 or CLDN4 rendered human ovarian carcinoma 2008 cells resistant to cDDP in both in vitro culture and in vivo xenograft model. The net accumulation of platinum (Pt) and the Pt-DNA adduct levels were reduced in CLDN3KD and CLDN4KD cells. The endogenous mRNA levels of copper influx transporter CTR1 were found to be significantly reduced in the knockdown cells, and exogenous expression of CTR1 restored their sensitivity to cDDP. Reexpression of an shRNAi-resistant CLDN3 or CLDN4 up-regulated CTR1 levels, reversed the cDDP resistance, and enhanced TJ formation in the knockdown cells. Baseline copper (Cu) level, Cu uptake, and Cu cytotoxicity were also reduced in CLDN3KD and CLDN4KD cells. Cu-dependent tyrosinase activity was also markedly reduced in both types of CLDN knockdown cells when incubated with the substrate l-DOPA. These results indicate that CLDN3 and CLDN4 affect sensitivity of the ovarian cancer cells to the cytotoxic effect of cDDP by regulating expression of the Cu transporter CTR1.
Moores UCSD Cancer Center, University of California-San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, USA.
Xiying
X
Shang
Xinjian
X
Lin
Gerald
G
Manorek
Stephen B
SB
Howell
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D062465:Claudin-3 / Q000235:genetics / Q000378:metabolism*; D062506:Claudin-4 / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D000079923:Copper Transporter 1; D019008:Drug Resistance, Neoplasm; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D014442:Monophenol Monooxygenase / Q000378:metabolism; D009368:Neoplasm Transplantation; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D019108:Tight Junctions / Q000502:physiology; D014183:Transplantation, Heterologous
D000970:Antineoplastic Agents; D027682:Cation Transport Proteins; D062465:Claudin-3; D062506:Claudin-4; D000079923:Copper Transporter 1; D012333:RNA, Messenger; C490079:SLC31A1 protein, human; D003300:Copper; D014442:Monophenol Monooxygenase; D002945:Cisplatin