A Novel Drug Modulator Diarylheptanoid (trans-1,7-Diphenyl-5-hydroxy-1-heptene) from Curcuma comosa Rhizomes for P-glycoprotein Function and Apoptosis Induction in K652/ADR Leukemic Cells

Curcuma comosa has been used in traditional Thai medicine to treat menstrual cycle-related symptoms in women. This study aims to evaluate the diarylheptanoid drug modulator, trans-1,7-diphenyl-5-hydroxy-1-heptene (DHH), in drug-resistant K562/ADR human leukemic cells. This compound was studied due to its effects on cell cytotoxicity, multidrug resistance (MDR) phenotype, P-glycoprotein (P-gp) expression, and P-gp function. We show that DHH itself is cytotoxic towards K562/ADR cells. However, DHH did not impact P-gp expression. The impact of DHH on the MDR phenotype in the K562/ADR cells was determined by co-treatment of cells with doxorubicin (Dox) and DHH using an MTT assay. The results showed that the DHH changed the MDR phenotype in the K562/ADR cells by decreasing the IC(50) of Dox from 51.6 to 18.2 µM. Treating the cells with a nontoxic dose of DHH increased their sensitivity to Dox in P-gp expressing drug-resistant cells. The kinetics of P-gp mediated efflux of pirarubicin (THP) was used to monitor the P-gp function. DHH was shown to suppress THP efflux and resulted in enhanced apoptosis in the K562/ADR cells. These results demonstrate that DHH is a novel drug modulator of P-gp function and induces drug accumulation in the Dox-resistant K562 leukemic cell line.