Combination of Curcumin and Cisplatin Induces Apoptosis and Anti-migration Effect in Lung Adenocarcinoma through AKT/mTOR Pathway and Independent of MAPK (ERK/RSK) pathway in Vitro

Abstract

Background: Lung cancer is a leading cause of mortality worldwide. Cisplatin is one of the most common anti-cancer drugs. However, cisplatin loses its sensitivity in the late stages of cancer and has severe side effects. This raises the need for an alternative treatment method such as combination with natural products like curcumin. Aims: This study aimed to investigate the effect of the combination of cisplatin and curcumin on inducing apoptosis and anti-migration effect in A549 lung cancer cell line, as well as their effect on the protein expressions of MAPK downstream mediators ERK1/2 and RSK1, as well as AKT/mTOR pathway, and their effect on the cell cycle phases of A549 cells. Method: This was achieved by conducting MTT assay to measure A549 cell viability, western blotting analysis was used to examine the proteins expression, scratch migration assay was conducted to measure the migration rate of A549 cells, while flow cytometry analysis used to evaluate the cell cycle phases. Results: This study showed that the combination of cisplatin and curcumin significantly decreased the cell viability of A549 cells compared to the single treatment of cisplatin and curcumin at 24hrs and 48hrs time points. Similar effect was observed in the scratch migration assay where the combination of cisplatin and curcumin significantly decreased the migration of A549 cells after 24hrs of treatment compared to the single treatment of cisplatin and curcumin (80.3% 10μM cisplatin and 70.2% 30μM curcumin vs 37.9% combination group ± 2.64, P<0.01). The combination of cisplatin and curcumin did not have a significant effect on the expression of p-ERK/ERK and p-RSK/RSK, which indicates that the combination effect is independent of MAPK pathway. However, the combination of cisplatin and curcumin significantly decreased the expression of p-AKT/AKT at 48hrs time point. It also decreased the expression of AKT downstream mediator p-mTOR/mTOR at 48hrs. The combination resulted in significant cellular arrest at G2/M phase at 24hrs time point (22.6% NT vs 33.3% combination group ± 1.98, P<0.05), and significant cellular arrest at S phase at 48hrs time point (2.77% NT vs 32.06% combination group ± 1.81, P<0.05). Conclusions: This study found that combining cisplatin and curcumin is independent of ERK/RSK pathway, while it downregulated the expression of AKT/mTOR pathway, as well as deregulated the cell cycle phases of lung adenocarcinoma cells. The findings of this study demonstrate AKT pathway as a vital therapeutic target resulted from the combination of cisplatin and curcumin, which will pave the way to use this combination as a more targeted and effective alternative to the traditional treatment strategies.