Anticancer effects of Pimaric acid is mediated via endoplasmic reticulum stress, caspase-dependent apoptosis, cell cycle arrest, and inhibition of cell migration in human ovarian cancer cells

Abstract

Pimaric acid is a naturally occurring resin and has been found to perform many pharmacological activities including, anticancer activity. However, the role of Pimaric acid in ovarian cancer is still not known. This investigation aimed to evaluate the anticancer effects of Pimaric acid and its molecular mechanism in human ovarian cancer cells. MTT assay was used to examine cell viability. Cell morphology was determined through phase contrast microscopy. DAPI staining and TUNEL assay were performed for apoptotic study. Examination of cell cycle phase distribution was carried out through flow cytometry. In vitro wound healing assay was used for cell migration determination. Pimaric acid induced cytotoxicity in human ovarian cancer cells (PA-1) in a dose-dependent manner without causing too much cytotoxicity in human ovarian epithelial cells (T1074). Cell morphology in treated cancer cells showed significant changes compared to untreated controls. Furthermore, it was observed that the cytotoxic effects of Pimaric acid were apoptosis-mediated and caspase-dependent cascade. Western blotting analysis showed that the expression of apoptosis-associated proteins like BAX, p-53 and caspase-3 was enhanced and BCL-2 expression was diminished. The induction of cytotoxicity was mediated via endoplasmic reticulum stress through expressions of related proteins which showed a tremendous increase in p-PERK, PERK, AT-4, CHOP and IRE-1 levels after treatment. Cell cycle analysis through cytometry showed significant results as it revealed G2/M phase cell cycle arrest. Furthermore, the in vitro wound healing assay showed specific anti-migratory effects of Pimaric acid on PA-1 cells. In conclusion it can be assumed that Pimaric acid may act as a potential anticancer agent against ovarian carcinoma, however further investigations are required to validate this initial claim.