The anti-tumor and immunomodulatory effect of α-tocopherol on tumor microenvironment in an in vitro model of colon cancer.

BACKGROUND

Colorectal cancer (CRC) requires effective preventive measures due to its high prevalence, mortality rate, and impact on patients' lives. Therefore, this study aimed to assess the immunomodulatory effects of α-tocopherol (α-TOC) within the tumor microenvironment (TME) of CRC using a co-culture model.

METHODS

To characterize the biological effects of vitamin E, apoptosis assays, scratch tests, and real-time PCR were performed to investigate the direct effect of α-TOC (2.2, 22, and 220 μM) on the viability, migration, and pathway mechanisms of the SW480 CRC cell line. PBMCs (peripheral blood mononuclear cells) were co-cultured with the SW480 to assess the effects within the TME and then treated with α-TOC. We evaluated the effect of α-TOC on the viability of PBMC and the co-culture of PBMC+SW480 using an MTT assay. Additionally, we performed ELISA and flow cytometry to assess the effect of α-TOC on the secretion of IFN-γ and the population of immunomodulatory cells such as MDSCs and Treg cells, respectively.

RESULTS

Our findings revealed that α-TOC significantly induced apoptosis in SW480 cells and promoted the proliferation of PBMCs (P < 0.05). In the co-culture group (PBMC+SW480), α-TOC stimulated PBMC proliferation, increased IFN-γ secretion, and reduced the population of MDSCs (P < 0.05). However, α-TOC did not significantly affect the Treg population.

CONCLUSION

These results suggest that, in addition to its direct anti-tumor effects, α-TOC also shows immunomodulatory properties in the context of colon cancer in an in vitro model.