Exploring the effects of alpha-pinene on apoptosis induction in human colon cancer cells via the PI3K/AKT signaling pathway: an in vitro study

Abstract Background Colorectal carcinoma ranks as the second most prevalent neoplasm in females and the third most prevalent in males. Methods In this investigation, we examined the influence of alpha-pinene (ALP), classified as a monoterpene, on the proliferation of HT-29 human colorectal carcinoma cells via the PI3K/AKT signaling cascade. HT-29 cells were exposed to a range of ALP concentrations. The survival rate of the cells was assessed through the MTT assay; while, apoptotic events were evaluated using flow cytometry in conjunction with Annexin V/PI staining. Additionally, cell cycle dynamics were scrutinized through fluorescence-activated cell sorting. The expression levels of Bax, Bcl-2, Caspase-3, PI3K, and AKT at both the gene and protein levels were quantified employing real-time PCR and western blot techniques. Results ALP treatment led to a significant, dose-dependent decrease in cell viability, with prolonged exposure exacerbating cytotoxic effects. Apoptosis analysis showed that ALP significantly increased apoptotic cells after 24 h of treatment. Cell cycle analysis showed that ALP induces G2/M phase arrest and inhibits cell proliferation and DNA synthesis. Gene expression analysis revealed upregulation of pro-apoptotic genes Bax and caspase-3 and decreased anti-apoptotic gene Bcl-2. Furthermore, the administration of ALP led to a notable reduction in both the gene and protein expression levels of PI3K and Akt, suggesting a suppression of the PI3K/Akt signaling cascade. Conclusion ALP inhibits HT-29 colon cancer cell growth by reducing cell viability, inducing apoptosis, and blocking the PI3K/AKT pathway. These findings highlight ALP’s potential as a therapeutic candidate for colorectal cancer.