Astaxanthin inhibits hallmarks of cancer by targeting the PI3K/NF-κΒ/STAT3 signalling axis in oral squamous cell carcinoma models.

Aberrant activation of the PI3K/Akt signalling pathway, a major driving force of diverse cellular processes has been implicated in tumour development and progression. Here, we report that astaxanthin (AXT), a potent antioxidant ketocarotenoid prevents cancer hallmarks by inhibiting PI3K/Akt and the associated downstream NF-κB and STAT-3 signalling pathways in SCC131 and SCC4 oral cancer cells as well as in the hamster buccal pouch carcinogenesis model. Using small molecule inhibitors of NF-κB, STAT-3 and PI3K and by overexpression of PI3K, we provide evidence to show that AXT inhibits NF-κB and STAT-3 signalling and cancer hallmarks by restraining the kinase activity of PI3K/Akt. Additionally, AXT downregulated the noncoding RNAs (ncRNAs), miR-21 and HOTAIR that influence PI3K/Akt signalling emphasising its modulatory effects on epigenetic regulation. Ethyl cellulose-based AXT nanoparticles showed greater chemotherapeutic efficacy in the hamster oral carcinogenesis model compared to native AXT. We suggest that AXT prevents cell proliferation, apoptosis evasion, invasion and angiogenesis by intercepting the crosstalk between the PI3K/Akt, NF-κB and STAT-3 signalling circuits both in vitro and in vivo. Astaxanthin that abrogates the PI3K/Akt signalling axis, a central hub that orchestrates acquisition of cancer hallmarks is a promising candidate for anticancer drug development.