Anti-Cancer Effects of Cordycepin on Oral Squamous Cell Carcinoma Proliferation and Apoptosis in Vitro

Cordycepin is an active component of parasitic fungus, Cordyceps militaris, and investigated for its pharmacologic efficacy. Increasing evidence supports the anti-tumoral effects of Cordycepin in various types of human solid tumors. We sought to determine the effects of Cordycepin on oral squamous cell carcinoma in vitro and in vivo. Two oral squamous cell carcinoma cell lines, KB and HSC3, were used in this study. Cells were treated with Cordycepin or diluent, followed by determinations of proliferation by sulforhodamine method and apoptosis by TUNEL assay in vitro. For in vivo experiments, tumor cells were transplanted into nude mice, followed by treatment with Cordycepin or control diluent. In addition, cells were examined for expression of adenosine receptor isotypes, and tested whether cordycepin-induced effects were mediated through adenosine receptors by combinatorial treatment of cordycepin and antagonists specific to each isotype of adenosine receptors. Two cell lines expressed protein of all types of adenosine receptors stronger than normal oral keratinocytes. Cordycepin showed anti-proliferating effect and apoptotic effect on both cell lines in vitro in a dose dependent manner. However, any adenosine receptors did not reverse the effect of cordycepin. In our in vivo experiments, cordycepin failed to decrease the tumor volume significantly, and failed to induce more apoptosis of tumor cells. Cordycepin has anti-proliferating effect and induces apoptosis not mediated by adenosine receptor on oral squamous cell carcinoma cells in vitro. However, in vivo results suggest that cordycepin in itself has a limited value as a novel chemotherapeutic agent for oral squamous cell carcinoma