Investigating the combined effect of ursolic acid and alpelisib on inhibiting cell proliferation and the expression of HIF1α on 4T1 breast cancer cell line

 Alpelisib and Ursolic acid are two compounds that have been shown to have potential as anti-cancer agents. Alpelisib is a selective inhibitor of the PI3K pathway, while Ursolic acid is a natural pentacyclic triterpene compound found in various plants that reveals anti-cancer, antioxidant and anti-inflammatory characteristics. The hypoxia-inducible factor 1α (HIF1α) is a transcription factor that plays a key role in regulating tumor cell survival, apoptosis, tumorigenesis and growth in low-oxygen environments. This study aims to determine the effects of Ursolic acid and Alpelisib on the expression of HIF1α gene on 4T1 cell line.

 In the current experimental study, IC50 concentrations of both Ursolic acid and Alpelisib were determined on 4T1 cells. Then cells were treated with determined IC50 concentrations of Ursolic acid, Alpelisib and the combination of half of the IC50 concentration of both drugs for 24 hours. After the treatment, viability was assessed with MTT assay and the expression of HIF1α gene was appraised by Real-time PCR. Finally, statistical analysis was accomplished by ANOVA using GraphPad Prism 8.4 software.

 The results of this study showed that the anti-proliferative effect of the drug combination was synergistic and concentration-dependent. The maximum decrease (74.17 % with UA and 64.04 % with Alp) in viability was observed in high doses of treatment with drugs. IC50 values of Ursolic acid and Alpelisib were 168.314 µM and 6.377 µM, respectively. Based on the real-time PCR results, HIF1α gene expression was significantly decreased in both single- treatment and combination groups, compared to the control group (P<0.05).

 The results of this study showed that both Alpelisib and Ursolic acid alone or in combination with each other could have anti-cancer effects by reducing HIF1α gene expression. Further studies are needed to determine the efficacy and safety of these compounds in vivo.