Dose-dependent effects of curcumin on 22Rv1 prostate cancer cell line

Background: Prostate cancer (PCa) is the second most frequent cancer type in the male population over 66 years. Curcumin is a polyphenolic natural compound extract from the rhizomes of Curcuma longa Linn (Zingiberaceae family) which showed important anticancer effects by inhibiting cell proliferation and inducing apoptosis in several cancer types. Recently, some studies reported that oral curcumin lowered PSA levels, but it did not modify the clinical outcomes in patients with prostate cancer who received intermittent androgen deprivation (IAD). Other studies reported that high concentrations of curcumin were toxic for patients. Methods and results: In this study we showed that low doses of curcumin can induce senescence-like effects in 22Rv1 cell line while higher concentrations have cytotoxic effects. Five,15 and 30 µM curcumin blocked cell cycle in G2/M phase but only 15 and 30 µM curcumin induced cell death. In addition, an increased expression of p21, a known senescence marker, was detected in 22Rv1 cells treated with curcumin in every experimental condition. However, the expression of p16, another known senescence marker, increased only to 30 µM curcumin. Conclusion: In the context of personalized approach in PCa care, we suggest that the appropriate concentration of curcumin used in combination with radiotherapy or with androgen deprivation therapy (ADT) could be taken into consideration.