Caffeic Acid Intervention Slows Cancer Cell Growth While Reversing the Th2‐Biased Immune Balance in Human Colorectal Cancer HT‐29 Cell‐Bearing Mice
Hsuan‐Yin Chen, Chang‐Lin Lin, Chou‐Chen Chen, Jin‐Yuarn LinABSTRACT
The effects of caffeic acid (CA) intervention on the relationship between human colorectal cancer (CRC) HT‐29 cell growth and Th1/Th2 immune balance in vivo are not fully understood. To unravel the perplexity, this study examined the impact of CA intervention on the relationship between tumor growth and the Th1/Th2 immune balance in CRC‐bearing mice for 35 days using an established xenograft animal model. The BALB/c nude mice were subcutaneously xenografted with HT‐29 cells and received three different CA doses daily, including 6 mg (low‐dose), 30 mg (medium‐dose), and 60 mg CA/kg AIN‐93 M feed (high‐dose). The results showed that CA intervention slightly decreased tumor volumes and weights in CRC‐bearing mice. Meanwhile, the CRC‐bearing mice tended to have a Th2‐biased immune balance, as indicated by the cytokine secretion profile of splenocytes. Notably, CA intervention dose‐dependently increased Concanavalin A‐stimulated IFN‐γ secretion and the IFN‐γ (Th1)/IL‐10 (Th2) secretion ratio. There is a negative correlation between IFN‐γ/IL‐10 secretion ratios and tumor weights, suggesting that higher doses of CA intervention may reverse the immune balance toward a Th1‐dominant immune response in CRC‐bearing mice. CA showed modest trends toward reduced tumor burden under the experimental conditions tested, while reversing the Th2‐biased immune balance in CRC‐bearing mice.