Improving anti-tumor outcomes for colorectal cancer therapy through in situ thermosensitive gel loading harmine

Colorectal cancer is a common malignant tumor that seriously endangers human health. Harmine (HM), a natural product, has been shown to have a significant inhibitory effect on various cancers. However, systemic injection of HM can cause central nervous toxicity, which limits its clinical application. Local administration of HM overcomes this problem to a certain extent. In this study, we prepared an in situ thermosensitive HM gel preparation (HM gel), and used it to treat colon cancer with reduced toxic side effects and prolonged residence time of HM at the tumor site. We employed a central composite design and response surface methodology to optimize the formulation, and evaluated the physicochemical properties, rectal retention capacity, and in vitro and in vivo antitumor effects of HM gel on colon 26 tumor cells. The results showed that HM gel had a significant inhibitory effect on the growth of colon 26 cells in vitro. In an orthotopic tumor-bearing mouse model, HM gel exhibited an obvious inhibitory effect on tumor growth and metastasis, and significantly prolonged the survival period. In conclusion, HM gel exhibited significant anti-tumor effects on colon cancer, and therefore presents a promising formulation for the treatment of colorectal cancer.