Significant decrease in the viability and tumor stem cell marker expression in tumor cell lines treated with curcumin

Abstract

Lung cancer, colon cancer and Leukemia are among the ten most common cancers worldwide with high incidence of recurrence, metastasis and chemoresistance. Limitations of therapy have been attributed to cancer stem cells (CSCs). The natural multi-targeting agent curcumin (turmeric) has shown significant anti-cancer effects. In this study the authors investigated the effect of curcumin on cancer cell viability, proliferation and suppression of CSCs markers (CD44, CD133, ALDH1) in vitro. Additionally, as limitations for curcumin application arise from its poor bioavailability, the stability of curcumin in different media conditions was investigated.The effect of curcumin on three cancer cell lines (A549, HCT116, 183E95) was investigated with MTT-assay, Flowcytometry, Immunofluorescence and western blotting. Stability of curcumin (diferuloylmethane) and curcuminoids (bisdemetoxycurcumin; desmetoxycurcumin) was determined by HPLC technique in A549 cells in different culture systems (culture medium with/without 10 % FCS, culture medium and cells with/without 10 % FCS) every three hours for over 24 h.Curcumin suppressed cell viability and proliferation as well as expression of CD44 in a time- and dose-dependent manner in all cell lines. Exemplary immunofluorescent and western blot investigation of HCT116 demonstrated that curcumin down-regulated CD44, CD133 and ALDH1 time-dependently. Stability of curcumin was markedly prolonged in a medium supplemented with 10 % FCS independent of application to cell cultures. The most stable curcuminoid over time was bisdemetoxycurcumin and the least stable was Curcumin.The results underline the immense potential of curcumin as an anti-cancer agent by targeting CSCs and further demonstrate that adequate media composition can significantly enhance curcumin stability in vitro.