KW2478 and Cisplatin Synergistically Anti-colorectal Cancer by Targeting PI3K/AKT/mTOR Pathway

Objective: The objective of this study is to examine the impact of KW-2478 combined with DDP on colorectal cancer cells both in vitro and in vivo and to elucidate the molecular mechanism of KW-2478 in colorectal cancer.

Methods: qRT-PCR and Western blot were employed to assess HSP90 mRNA and protein expression in normal intestinal epithelial and colorectal cancer cells. DLD-1 and HCT116 were selected for the experiment. CCK-8 was used to detect cytotoxicity; apoptosis rate was measured using flow cytometry; Western blot was employed to measure the expression levels of apoptotic and PI3K/AKT/mTOR pathway proteins. HCT116 was used to construct a subcutaneous tumor model in nude mice. After treatment with KW-2478 and DDP, the growth rate, volume, and weight of the tumor were observed. The expression of Ki67 was detected by immunohistochemistry. Apoptosis of tumor cells was detected using TUNEL. Western blot was employed to measure the expression levels of apoptotic and PI3K/AKT/mTOR pathway proteins.

Results: HSP90 mRNA and protein levels were elevated in colorectal cancer cells compared to normal colorectal epithelial cells. HSP90 mRNA and protein expression levels were also significantly elevated in HCT116 and DLD-1 cells compared to other colorectal cancer cells. In DLD-1 and HCT116 cells, KW2478 and DDP inhibited cell viability. The combination of KW2478 and DDP exhibited a significantly higher inhibitory effect compared to either KW2478 or DDP alone. DDP markedly triggered apoptosis in HCT116 and DLD-1. KW2478 at 3 μg/ml and 6 μg/ml induced apoptosis in HCT116 cells but not in DLD-1 cells. The combination of KW2478 and DDP induced a significantly higher apoptosis rate as compared to either KW2478 or DDP alone. Treatment of HCT116 and DLD-1 with KW2478 or DDP alone increased Bax, Caspase9, and Caspase3 protein expression, while decreasing BCL-2. The KW2478+DDP combined treatment group exhibited more significant changes. Phosphorylation of PI3k, AKT, and mTOR decreased in the KW2478 or DDP treatment groups, with more significant changes observed in the KW2478 + DDP combination group. The growth rate, volume, and weight of subcutaneous tumors in the KW2478 or DDP treatment groups were significantly lower than control, and the KW2478+DDP combination group was more affected. Ki67 expression in subcutaneous tumors was reduced in the KW2478 or DDP treatment groups compared to the vehicle control group, with the lowest expression observed in the KW2478 + DDP combination group. The fluorescence intensity of subcutaneous tumors was higher in both the KW2478 and DDP treatment groups compared to the vehicle control group, and the KW2478 + DDP combination group exhibited the strongest fluorescence intensity among them.

Conclusion: The combination of KW2478 and cisplatin inhibits colorectal cancer cell proliferation and induces apoptosis by regulating the PI3K/AKT/mTOR pathway.