PT - JOURNAL ARTICLE AU - TEA KUITTINEN AU - PÄIVI ROVIO AU - TIINA LUUKKAALA AU - MARITA LAURILA AU - SEIJA GRÉNMAN AU - ANNE KALLIONIEMI AU - JOHANNA MÄENPÄÄ TI - Paclitaxel, Carboplatin and 1,25-D3 Inhibit Proliferation of Ovarian Cancer Cells <em>In Vitro</em> AID - 10.21873/anticanres.14294 DP - 2020 Jun 01 TA - Anticancer Research PG - 3129--3138 VI - 40 IP - 6 4099 - http://ar.iiarjournals.org/content/40/6/3129.short 4100 - http://ar.iiarjournals.org/content/40/6/3129.full SO - Anticancer Res2020 Jun 01; 40 AB - Background/Aim: The combination of paclitaxel and carboplatin is the standard chemotherapy for ovarian cancer. Previous studies have implied that vitamin D (1,25-D3) may have growth inhibitory effects in ovarian cancer. This study aimed to investigate the effect of paclitaxel, carboplatin and 1,25-D3 on the growth of ovarian cancer cells in vitro, based on the hypothesis that 1,25-D3 might potentiate the effect of paclitaxel and/or carboplatin. Materials and Methods: Three non-commercial ovarian carcinoma cell lines UT-OV-1(mucinous), UT-OV-3B (serous) and UT-OV-4 (endometrioid) were exposed to different concentrations of 1,25-D3, paclitaxel and carboplatin, respectively. The cell viability was measured using a Crystal violet assay kit. The cellular vitamin D receptor (VDR) mRNA levels were measured by qRT-PCR using the LightCycler equipment. Results: The growth-inhibitory effect of the combination of paclitaxel and carboplatin was 56% in UT-OV-1, 33% in UT-OV-3B and 47% in UT-OV-4 cells. Single 1,25-D3 (10 μM) inhibited the growth of UT-OV-3B and UT-OV-4 by 23% and 28%, respectively, whereas no effect was seen in UT-OV-1 cells. These results are in line with the finding that the expression of VDR was high in UT-OV-3B and UT-OV-4, but very low in UT-OV-1. The combination of 1,25-D3, paclitaxel and carboplatin resulted in 61%, 46% and 58% growth reduction in UT-OV-1, UT-OV-3B and UT-OV-4 cells, respectively. The additive effect of 1,25-D3 was 21% in UT-OV-4, 20% in UT-OV-3B and 12% in UT-OV-1 cell line. Conclusion: The results imply that combining 1,25-D3 with paclitaxel and carboplatin may potentiate their growth inhibitory effect on ovarian cancer cells with high VDR expression.