Stevioside inhibits colorectal cancer progression by regulating macrophage polarization

ObjectiveThe study aimed to explore the inhibitory effect of stevioside on colorectal cancer and its molecular mechanism.MethodsColorectal cancer cells were selected for functional testing, including the following groups: 0 μM stevioside, 1 μM stevioside, 2.5 μM stevioside and 5 μM stevioside. CCK-8 kit and EdU staining were employed to assess the cell viability. Cell apoptosis was deterred by flow cytometry. Western blot assay was utilized to detect the protein expressions of cleaved-caspase-3, Bax, Bcl-2, E-cadherin and Vimentin. The polarization of macrophage was evaluated through flow cytometry, western blot and immunofluorescence staining. The effect of stevioside on the proliferation of tumor tissue was detected by tumor formation and immunohistochemical staining in nude mice.ResultsStevioside exhibited a significant concentration-dependent inhibitory effect on the proliferation, migration, and invasion of colorectal cancer cells, while promoting apoptosis <i>in vitro</i>. Following stevioside treatment, there was a notable reduction in tumor volume and weight observed. Flow cytometry and immunohistochemical staining results showed that compared with control group, CD86+ cell ratio was increased in stevioside treatment group, while the CD206+ cell ratio was decreased in stevioside treatment group. RT-qPCR analysis revealed that, compared to the control group, stevioside treatment significantly reduced the mRNA expressions of Arg-1 and IL-10, while concomitantly increasing the mRNA expressions of IL-12 and TNF-α in a concentration-dependent manner.ConclusionStevioside possesses the ability to significantly hinder the proliferation of colorectal cancer cells and induce apoptosis, the mechanism of which may be closely related to the regulation of macrophage M1 polarization.