Antitumor Effects and Mechanisms of Curcumin On Human Multiple Myeloma Cell Lines.

Multiple myeloma(MM) is a malignant plasma disease, which is characterized as high relapse rate and high resistance to chemotherapy. Curcumin is a polyphenol derived from the rhizome of Curcuma spp. It possesses diverse pharmacologic actions, such as antitumor, anti-inflammatory,anti- oxidation properties .Curcumin has the property of inhibit multiple tumor cell lines, in which included multiple myeloma cell. The real mechanism is not completely clear yet. We explored the mechanisms of curcumin on human multiple myeloma cell lines (RPMI8226 and H929), and investigated whether the combination of curcumin and adriamycin(Adr) has a synergistic effect.

The effect of curcumin on proliferation of RPMI8226 and H929 was observed with MTT assay. The synergetic effect of curcumin and Adr was analyzed by median-effect principle. Cell cycle distribution and apoptosis were studied with flow cytometry. Expression of surviving, bcl-2, bax mRNA was detected by RT-PCR.

Curcumin could inhibit the proliferation of RPMI8226 and H929 cells in a time- and dose-dependent manner. The IC₅₀ values for RPMI8226 and H929 cell line were 12.15 μmol/L,17.24μmol/L respectively. The combination of curcumin and Adr showed synergistic effect even at low concentration of Adr. Apoptotic ratio of treated cells was significantly higher than untreated controls (36.9% vs 10.6%, p<0.05). Cells treated with curcumin showed cell cycle arrest at G2/M phase. Curcumin upregulated expression of survivin, bcl-2, while bax mRNA was significantly downregulated.

Curcumin could suppress the proliferation of multiple myeloma cells and induce apoptosis. Adr combining with curcumin can show synergistic effect at low concentration of Adr. The mechanism of curcumin's antitumous effect might be related to down-regulation of surviving, bcl-2 mRNA and up-regulation of bax mRNA.

No relevant conflicts of interest to declare.