Effects of 25-hydroxyvitamin D3 and Digitoxin in Prostate Cancer Cells

Prostate cancer is the most occurring form of cancer in men in Sweden and new candidates for treatment towards advanced phases of prostate cancer needs to be investigated. One suggested treatment is vitamin D which will mediate effect via VDR and PDIA3 and cause cell cycle arrest. Another treatment is digitoxin which will cause accumulation of intracellular Ca leading to apoptosis. The aim of the project of was to investigate potential synergistic effects of 25-hydroxyvitamin D3 and digitoxin in prostate cancer cell lines and find out effects mediated by PDIA3. DU145 and LNCaP cells were seeded and treated with 25-hydroxyvitamin D3 (10, 10, 10 M), digitoxin (25 ng/ml and 50 ng/ml) and four combinations of 25-hydroxyvitamin D3 and digitoxin. Cell viability assay was performed for determining the number of viable cells. Treatment with 25-hydroxyvitamin D3 10M + digitoxin 50ng/ml (68%), 25-hydroxyvitamin D3 10M + digitoxin 25ng/ml (39%), 25-hydroxyvitamin D3 10M + digitoxin 50ng/ml (69%), digitoxin 25ng/ml (26%) and digitoxin 50 ng/ml (44%) was statistically significant with increased cell viability compared to untreated control in DU145 after 48h of treatment. Treatment with 25-hydroxyvitamin D3 10M (12%) and 25-hydroxyvitamin D3 10M (12%) was statistically significant with increased cell viability compared to untreated control in LNCaP after 24h of treatment. The conclusion based on results from this study is that a combination of digitoxin and 25-hydroxyvitamin D3 does not inhibit cell viability in DU145 or LNCaP cancer cell lines.