Cyclocommunol induces apoptosis in human oral squamous cell carcinoma partially through a Mcl-1-dependent mechanism

Area of Science:

• Natural Product Chemistry
• Cancer Biology
• Molecular Pharmacology

Background:

• Breadfruit extracts exhibit antitumor properties against cancer cell lines.
• The precise mechanism underlying breadfruit's antitumor activity remains largely unknown.

Purpose of the Study:

• To investigate the proapoptotic effects of cyclocommunol (CYC), a prenylflavonoid derived from breadfruit.
• To elucidate the mechanism of CYC action in two oral squamous cell carcinoma (OSCC) cell lines (SCC2095 and Ca922).

Main Methods:

• Cell viability was assessed using MTT assays and propidium iodide/annexin V staining.
• Mechanisms were explored via Western blotting, acridine orange staining, and confocal microscopy.
• Mcl-1's role was investigated through overexpression experiments in SCC2095 cells.

Main Results:

• CYC demonstrated antiproliferative effects on SCC2095 and Ca922 cells with IC50 values of 4.2 and 5.0 µM at 48h, respectively.
• CYC induced apoptosis in a caspase-dependent manner, involving the down-regulation of Akt/mTOR signaling and Mcl-1.
• Reactive oxygen species generation and autophagy were observed, and Mcl-1 overexpression partially reversed CYC-induced apoptosis and cytotoxicity.

Conclusions:

• Cyclocommunol (CYC) exhibits significant proapoptotic activity against oral squamous cell carcinoma (OSCC).
• The proapoptotic effect of CYC is partly mediated by the down-regulation of Mcl-1.
• CYC holds translational potential as a therapeutic agent for OSCC.