Background: Cancers are one of the commonest causes of deaths globally . Reports indicate that greater than sixty percent of cancers in the world occur in low and middle-income countries with about seventy percent of all cancer deaths occurring in these regions. Conventional cancer treatments involve surgery, radiotherapy, chemotherapy, etc. However, the negative side effects such as high cost and toxicity associated with these treatment options have increased the demand for less toxic and less expensive anti-cancer drugs from natural sources. One of such natural products believed to have anti-cancer potential is cryptolepine, an alkaloid extracted from the roots of Western and Central African plant Cryptolepis sanguinolenta . In addition to its anti-cancer potential, cryptolepine has been reported to possess a myriad of pharmacological activities. However, the mechanisms underlying the anti-cancer and pharmacological activities of cryptolepine have not been fully explored. The current study sought to determine the mechanism underlying the anticancer properties of cryptolepine.
Methods: We screened 45 immune and cancer signalling pathways for their regulation following treatment with cryptolepine using the dual-luciferase based Cignal Finder Multi-Pathway Reporter Arrays to pinpoint which pathways are regulated by cryptolepine. Additionally, the effects of cryptolepine on the transcript levels of interferon regulatory factor 1(IRF1), progesterone receptor (PR), hypoxia-inducible factor-1 alpha (HIF-1α) and signal transducer and activator of transcription 3 (STAT3) were assessed by real-time quantitative polymerase chain reaction.
Results: We observed that of the 45 immune and cancer signalling pathways screened, nine were up-regulated while twenty-seven were down-regulated by cryptolepine. However, cryptolepine had no effect on nine of the pathways screened. We also observed that cryptolepine induced an increase in the transcript levels of IRF1 and PR but decreased that of HIF1-α and STAT3.
Conclusion: The upregulation of human anti-cancer pathway genes including IRF-1 and PR and concomitant down-regulation of pro-cancer pathway genes including HIF1-α and STAT3 suggest additional mechanisms through which cryptolepine exhibits its anti-cancer activities.