Potent anti-cancer activity of Sphaerocoryne affinis fruit against cervical cancer HeLa cells via inhibition of cell proliferation and induction of apoptosis

Abstract

Background: Cervical cancer remains a significant global health issue, highlighting the need for effective therapeutic strategies. Given that Sphaerocoryne affinis (SA) has shown potential anti-cancer activity in several cancer types, herein, we investigate the effects of SA fruit (SAF) on human cervical cancer HeLa cells and their underlying mechanisms of action.

Methods: SAF extract cytotoxicity was assessed in various cancer cell lines. The effects of the hexane fraction (SAF-Hex) on HeLa cell viability, cell cycle protein expression, apoptosis, and DNA damage were evaluated using cytotoxicity assays, Western blotting, quantitative PCR, 4',6-diamidino-2-phenylindole (DAPI) staining, and a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.

Results: SAF-Hex selectively inhibited HeLa cell viability with an IC50 of 4.20 ± 0.36 µg/mL and a selectivity index of 5.11 ± 0.58. The time-dependent cytotoxicity assay showed decreased cell survival after 48 h of treatment, accompanied by morphological changes and apoptotic bodies in HeLa cells. SAF-Hex also suppressed HeLa cell cycle proteins (Cyclin E, CDK2, and CDK1), reduced PCNA transcription, and diminished AKT and mTOR activation, thus inhibiting cell proliferation. The increased γH2AX expression, DNA fragmentation, and caspases-3 and -9 activation indicated SAF-Hex-induced DNA damage and apoptosis. However, the BAX/BCL-2 ratio remained unchanged, and BAX and BCL2 expression was attenuated.

Conclusion: SAF-Hex effectively inhibits HeLa cell proliferation and induces DNA damage in that cervical cancer cell line activating apoptosis through the intrinsic pathway. Interestingly, the BAX/BCL-2 ratio remained unchanged while BAX and BCL2 transcription was attenuated. Hence, further research is required to explore this unexpected finding and facilitate the development of novel therapies targeting cervical cancer HeLa cells.

Keywords: Anti-cancer; Apoptosis; Cervical cancer; DNA damage; HeLa cells; Sphaerocoryne affinis.