Reovirus oncolysis in human head and neck squamous carcinoma cells

Objective: To determine whether reovirus, a double-standed RNA virus is effective on the growth of a human head and neck squamous cell carcinoma cell line. Designs: In vitro cell proliferation assay, KB cells, a human oral floor squamous cell carcinoma cell line, were treated with reovirus and the number of cells was quantitated by an assay, using trypan blue staining. In vivo tumor growth assay, KB cells were injected subcutaneously into athymic nude mice, which were given an intratumoral injection of reovirus to a maximum four times in every week. The tumor size was measured once a week. Simultaneously, apoptosis and necrosis of KB cells were investigated, using technique of immunohistochemistry. Results: In vitro, the multiplication of the KB cell was inhibited depending on the concentration of reovirus. In vivo, athymic nude mice bearing KB tumors were injected with the virus intratumorally, and the tumor growth was suppressed proportionally depending on the injection time of reovirus. Necrosis was recognized extensively in the pathological specimen. On the other hand, apoptosis-inducing effect was not obvious in these specimen. Conclusions: Reovirus suppressed tumor growth of KB cells in vivo as well as in vitro. The possibility that reovirus could become the means of treatment for head and neck carcinoma, was suggested with further work.