Chaga And Rosmarinic Acid Combined Treatment Inhibits HNSCC Cell Survival

Objectives: Rosmarinic acid (RA) is a water soluble polyphenolic compound that is found in various plants, including Rosmarinic officinals. Previous studies have shown that RA can inhibit proliferation and migration of HNSCC cells by attenuating EGFR activation and its downstream signaling pathways. Another natural cancer therapy that holds immense promise is the Chaga Mushroom (Inonotus obliquus). Chaga mushroom is regarded to have anti-tumor, immune modulating, cardiovascular, antiviral, antibacterial and anti-parasitic effects. Indeed a few studies have shown that Chaga mushroom extracts have anti-tumor effects, but the cellular mechanisms underlying these effects remain relatively unexplored. Given the overlapping and divergent mechanisms employed by these natural treatments to abrogate cancer growth and progression, we set out to explore the efficacy of the treatments either alone or in combination to combat HNSCC proliferation and cell survival. In the present study, we describe a novel role for Chaga extract in combination with RA as an inhibitor of proliferation, and promoter of autophagy and apoptosis in HNSCC.
Methods: Cellular proliferation profiles were examined in Chaga-treated, RA treated, combined Chaga/RA treated, and untreated HNSCC cell lines (UM-SCC-6 and UM-SCC-1) using the CyQUANT proliferation assay. Induction of autophagy and apoptosis was examined in untreated, Chaga-treated, combined Chaga/RA treated UM-SCC-6 cells using the Autophagy/Cytotoxicity Dual Staining Assay and flow cytometry, respectively. The influence of Chaga and combined Chaga/RA on LC3 cleavage was evaluated using Western-blotting techniques.
Results: Combined Chaga/RA treatment significantly inhibited 24-hour proliferation in UM-SCC-6 and UM-SCC-1 cells in a dose-dependent manner compared to untreated controls. The combined regimen increased autophagy, LC3 cleavage, and late apoptosis in UM-SCC-6 cell lines when compared to the untreated controls.
Conclusions: The present data suggests that the Chaga/RA regimen holds promise as a therapeutic agent against HNSCC with synergistic effects.