Components of heat-treated Helianthus annuus L. pectin inhibit tumor growth and promote immunity in a mouse CT26 tumor model

Abstract

Heat-treated pectin is known to have anti-tumor activity. The present study was designed to identify its active components and mechanism of action. Here, we investigated the anti-tumor effect of heat-treated Helianthus annuus L. pectin (HT-HAP), alkali-inactivated HT-HAP representing the pectin fragment fraction (HT-HAP-P), and heat-treated galacturonic acid representing the small molecule fraction (HT-HAP-S). Our results demonstrate that HT-HAP induces colon cancer CT26 cells apoptosis and inhibits CT26 tumor growth like 5-fluorouracil, whereas it shows no spleen and thymus toxicity in contrast to 5-fluorouracil. Mechanistically, HT-HAP attenuates Akt activation in tumors, and enhances it in the spleen and thymus. Interestingly, HT-HAP-S inhibited tumor growth, but promoted immunity mildly, whereas HT-HAP-P had little effect on tumor growth, but effectively promoted immunity. Overall, we attribute the anti-tumor effect from HT-HAP to the action of small molecules and the immune enhancement primarily to pectin fragments, with Akt activation being the underlying mechanism of action.

Keywords

• Akt
• Anti-tumor
• Heat-treated pectin
• Promote immunity