Anticancer effects of ginger extract and retinoic acid treatment on hela cervical cancer cells

Abstract

Introduction: Cervical cancer is the second most commonly diagnosed cancer in developing countries and the recurrence after primary therapy mainly due to the existence of drug-resistant cancer stem cells (CSCs) within the tumour. This study was aimed at identifying the anticancer effects of Retinoic acid-ginger extract combined therapy on HeLa cells representing an invasive form of aggressive adenocarcinoma of the cervical. Methodology: The Cell-titre-glo, CyQuant Proliferation and Caspase 3/7 assays as well as Isobologram-combination index analysis were conducted to examine the anticancer effects of RA and GE on HeLa cells viability, proliferation, ability to induce apoptosis and combined drug relationship respectively. Retinoic acid at (5- 50uM), ginger extract at (25-200uM) and RA-GE combination using RA (5-50uM) and GE (IC50:100uM and IC75:185uM) respectively were tested on HeLa cells. Findings: The inhibition percentage of cell viability and reduction in proliferative capacity of HeLa cells resulted in dose dependent manner with RA(5-50uM) (8.11% - 68.14%; 80.51% - 25.91%) GE(25-200uM) (13.59% – 76.49%; 80.06% - 22.67%) and combined RA(5-50uM)-GE(IC50;IC75) (54.67% - 97.54%; 43.23 -3.43%%) and GE(IC50;IC75) -RA(5-50uM) (51.60% - 94.80%; 45.73% - 5.13%) respectively. A clear HeLa cell viability inhibition along with reduced proliferative capacity is observed in all treatments. . In addition, the IC50 concentration of RA, GE as well as combined RAGE and GE-RA in HeLa cells were achieved at 25.6uM, 100uM, 17 uM and 21.4 uM respectively. Microscopy images of Solo RA-treated HeLa cells exhibited a more differentiated phenotype up to 25uM while ginger extract-treated HeLa cells appeared apoptotic from 40uM onwards. However, the combined RA-IC50ginger extract treatment induced a significant level of apoptosis in HeLa cells from as low as 6uM RA concentration compared to solo treatment, with RA (1.04%, negligible), ginger (IC25:1.54%, IC50:1.56%), ginger IC25-RA IC50 (1.41%) and ginger IC50-RA IC50 (1.66%). The combined RA-IC50ginger extract also exhibited a clear synergistic effect (CI: 1.20-0.26) on HeLa cells. The RA IC50-IC50ginger extract has the lowest metastatic index (36.78%). Conclusion: In conclusion, these findings altogether suggest that the RAginger extract therapeutic strategy may be potent anticancer agent for the targeted therapy of cervical cancer cells and other CSCs-enriched cancers.