Inhibitory Effect Of DHCF On The Proliferation Of Human Prostate Cancer Cells And Its Molecular Mechanism

OBJECTIVE:23,24-Dihydroxycucurbitacin (DHCF), a member of triterpenoids, is extractedfrom Hemslaya. More recently, DHCF were shown to have anti-inflammatory andanti-tumor effect. However, there is few report on its molecular mechanism. In thisstudy, we aimed to explore the effect of DHCF on human prostate cancer cells(LNCaP, DU145and PC3) and its underlying mechanism.METHODS:Human prostate cancer cells (PCa) were treated with graded doses of DHCF invitro. Cell proliferation, cell cycle distribution, and cell apoptosis were evaluatedusing MTT assay, flow cytometry, and fluorescent microscopy. Western blot analysisdetected the modulation of regulators in the cell cycle, apoptosis and signaltransductions.RESULTS:MTS assay showed that DHCF inhibited the proliferation of LNCaP, DU145andPC3cells in a dose-dependent manner and the IC50for them were5,7, and15mol/L,respectively. PI staining revealed that DHCF treatment induced cell cycle arrest at G2/M phase in all three PCa cell lines tested, but only led to significant apoptosis inLNCaP cells. Immunofluorescent staining showed that20mol/L DHCF treatmentfor4h resulted in G-actin depletion, actin aggregation and actin rod formation, withlittle effect on microtubule structure. Actin rods were colocalized with Cofilin rods,indicating the formation of Cofilin-actin rods. Western blot analysis revealed thatDHCF treatment resulted in dephosphorylation of Cofilin, upregulation of p21Cip1anddownregulation of Cyclin A in all three PCa cell lines.CONCLUSION:DHCF can significantly inhibit the proliferation of human PCa cells. LNCaP celllines are more sensitive than the other two cell lines. The effects may be broughtabout by inducing actin aggregation and Cofilin-actin rod formation, leading to cellcycle arrest, cytokinesis failure, and apoptosis.