Cryptolepine inhibits hepatocellular carcinoma growth through inhibiting interleukin-6/STAT3 signalling

Background Diverse signalling pathways are involved in carcinogenesis and one of such pathways implicated in many cancers is the interleukin 6/signal transducer and activator of transcription 3 (IL-6/STAT3) signalling pathway. Therefore, inhibition of this pathway is targeted as an anti-cancer intervention. This study aimed to establish the effect of cryptolepine, which is the main bioactive alkaloid in the medicinal plant Cryptolepis sanguinolenta, on the IL-6/STAT3 signalling pathway. Methods First, the effect of cryptolepine on the IL-6/STAT3 pathway in human hepatoma cells (HepG2 cells) was screened using the Cignal Finder Multi-Pathway Reporter Array. Next, to confirm the effect of cryptolepine on the IL-6/STAT3 signalling pathway, the pathway was activated using 200 ng/mL IL-6 in the presence of 0.5-2 mu M cryptolepine. The levels of total STAT3, p-STAT3 and IL-23 were assessed by ELISA. Results Cryptolepine downregulated 12 signalling pathways including the IL-6/STAT3 signalling pathway and upregulated 17 signalling pathways. Cryptolepine, in the presence of IL-6, decreased the levels of p-STAT3 and IL-23 in a dose-dependent fashion. Conclusion Our results demonstrated that cryptolepine inhibits the IL-6/STAT3 signalling pathway, and therefore cryptolepine-based remedies such as Cryptolepis sanguinolenta could potentially be used as an effective immunotherapeutic agent for hepatocellular carcinoma and other cancers.

Automated summary

The study revealed that Cryptolepine inhibits multiple signaling pathways including the IL-6/STAT3 pathway, and in the presence of IL-6, it dose-dependently decreases the levels of p-STAT3 and IL-23. This suggests that Cryptolepine-based remedies could potentially be used as an effective immunotherapeutic agent for hepatocellular carcinoma and other cancers.