Helicteric Acid, Oleanic Acid, and Betulinic Acid, Three Triterpenes from Helicteres angustifolia L., Inhibit Proliferation and Induce Apoptosis in HT-29 Colorectal Cancer Cells via Suppressing NF-κB and STAT3 Signaling

Colorectal cancer (CRC) is one of the most common malignancies and most frequent cause of cancer death worldwide. The activation of both NF-kappa B and STAT3 signaling and the crosstalk between them play an important role in colorectal tumor. Helicteres angustifolia L. is a type of commonly used Chinesemedicinal herb and possesses a wide variety of biological activities. In the present study, we investigate the effects of three triterpenes from H. angustifolia (HT) such as helicteric acid (HA), oleanic acid (OA), and betulinic acid (BA), on inhibiting CRC progression. Our results showed that HT extracts could decrease proliferation and induce apoptosis in HT-29 colorectal cancer cells. Moreover, HT extracts could suppress LPS-triggered phosphorylation of IKK, I kappa B, and NF-kappa B, attenuate IL-6-induced phosphorylation of JAK2 and STAT3, and suppress the expression of c-Myc, cyclin-D1, and BCL-xL, the downstream gene targets of NF-kappa B and STAT3. Therefore, HT extracts showed potent therapeutic and antitumor effects on CRC via inhibiting NF-kappa B and STAT3 signaling.