text: 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.
entities.id: T10 T11 T12 T13 T14 T15 T16 T17 T18 T19 T1 T20 T21 T22 T23 T24 T25 T26 T27 T28 T29 T2 T30 T31 T32 T33 T34 T35 T36 T37 T38 T39 T3 T40 T41 T42 T43 T44 T45 T46 T47 T48 T49 T4 T50 T51 T5 T6 T7 T8 T9
entities.type: CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL GENE-Y GENE-Y GENE-Y GENE-Y CHEMICAL GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-N GENE-Y GENE-Y GENE-N GENE-Y CHEMICAL GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y CHEMICAL GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-N GENE-Y GENE-Y GENE-Y CHEMICAL GENE-Y GENE-N CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL
entities.text: Pt Pt copper cisplatin cisplatin copper Claudin-3 CTR1 CLDN3 CLDN4 copper CTR1 CLDN3 CLDN3 CLDN4 tyrosinase CLDN CLDN3 CLDN4 Cu transporter CTR1 Cu CLDN3 CLDN4 claudin-4 CLDN4 CLND3 CLDN4 CLDN3 CLDN4 CLDN3 CLDN4 Cu CLDN3 CLDN4 CLDN3 CLDN4 CLDN3 CLDN4 copper influx transporter CTR1 Claudin-3 CTR1 Cu claudin-4 copper and cisplatin influx transporter Cu l-DOPA Cu cisplatin platinum