Investigation of natural phenanthrenes and the antiproliferative potential of juncusol in cervical cancer cell lines

Phenanthrenes isolated from Juncus species possess different biological activities, including antiproliferative and antimigratory effects.In this study, nine phenanthrenes isolated from the roots of Juncus inflexus were investigated for their antiproliferative activity on several gynecological cancer cell lines, using non-cancerous cells as controls.Antiproliferative activities of the compounds were determined by means of MTT assay. Flow cytometry was used for cell cycle analysis and determination of mitotic cells. Activities of caspase-3, -8, and -9 were detected by colorimetric kits. Tubulin polymerization was followed by kinetic absorbance determination. Action on tumor cell migration was described using wound healing assay. Western blot assays were used to determine apoptosis-related factors at protein level.Among the compounds tested, juncusol exhibited the most substantial antiproliferative effect against cervical cancer HeLa cells. It was also revealed that juncusol has a distinct growth inhibitory effect in cervical cancer cell lines of various HPV status: it was highly active in HPV type 18-positive HeLa cells, while it was inactive in HPV type 16-positive SiHa and CaSki cells. Cell cycle analysis showed an increase in G2/M and subG1 cell populations after juncusol treatment. Caspase-3, -8, and -9 were detected to be activated by juncusol in HeLa cells, indicating that juncusol induces apoptotic cell death. Moreover, juncusol inhibited tubulin polymerization, as well as EGFR activation, suggesting two possible additional mechanisms that may account for juncusol's inducing a G2/M-phase cell cycle arrest and inhibiting cell migration.These results suggest that juncusol is a potent antiproliferative agent against HPV-18 related cervical cancer and may be considered as a lead compound for the development of innovative anticancer agents.