Gracillin shows potent efficacy against colorectal cancer through inhibiting the STAT3 pathway.

Colorectal cancer (CRC) accounts for about 10% of all annually diagnosed cancers and cancer-related deaths worldwide. STAT3 plays a vital role in the occurrence and development of tumours. Gracillin has shown a significant antitumour activity in tumours, but its mechanism remains unknown. The human CRC cell lines HCT116, RKO, and SW480 and immunodeficient mice were used as models to study the effects of gracillin on cell proliferation, migration and apoptosis. These were evaluated by cell viability, colony formation, wound-healing migration and cell apoptosis assays. Luciferase reporter assay, and immunostaining and western blot analyses were used to explore the specific mechanism through which gracillin exerts its effects. Gracillin significantly reduces viability and migration and stimulates apoptosis in human CRC cells. It also significantly inhibits tumour growth with no apparent physiological toxicity in animal model experiments. Moreover, gracillin is found to inhibit STAT3 phosphorylation and STAT3 target gene products. In addition, gracillin inhibits IL6-induced nuclear translocation of P-STAT3. Gracillin shows potent efficacy against CRC by inhibiting the STAT3 pathway. It should be further explored as a unique STAT3 inhibitor for the treatment of CRC.

Effect of the isoflavone corylin from cullen corylifolium on colorectal cancer growth, by targeting the STAT3 signaling pathway.

BACKGROUND: Colorectal cancer (CRC) is one of the most common cancers worldwide. Corylin is an isoflavone extracted from Cullen corylifolium (L.) Medik., which is widely used anti-inflammatory and anticancer in Asian countries. Signal transducer and activator of transcription 3 (STAT3) plays an important role in the occurrence and development of CRC. PURPOSE: To analyze the antitumor activity of corylin in CRC and to elucidate its molecular mechanisms of action. METHODS: The human CRC cell lines HCT116, RKO, and SW480 and immunodeficient mice were used as models to study the antitumor effect of corylin. The potent anti-proliferative, anti-migration and proapoptotic effects of corylin were observed by cell viability, colony formation assays, wound-healing migration assay, and cell apoptosis assay. Immunostaining analysis and western blot analysis revealed inhibition of the STAT3 signaling axis. RESULTS: We found that corylin could significantly reduce the viability and stimulate apoptosis in human CRC cells in a dose-dependent manner. Corylin decreased the expression levels of P-STAT3 and STAT3 target proteins, such as myeloid cell leukemia-1(MCL-1), Survivin, VEGF and B-cell lymphoma 2 (BCL-2). It also upregulated the expression levels of the proapoptotic proteins BCL-2-associated X protein (BAX) and Cl-caspase 3. Moreover, corylin reduced the nuclear localization of STAT3. Furthermore, corylin inhibited the growth of the tumor in CRC mouse models. CONCLUSIONS: Our findings provide convincing results that could support the role of corylin in the treatment of CRC through inhibiting the STAT3 pathway. It is conceivable that corylin should be further explored as a unique STAT3 inhibitor in antitumor therapy.