05 using the Mann-Whitney test. The Statistical Package for Social Sciences, version 13.0 (IBM, Madrid, Spain) was used for data analysis. The principal aim of this study was to test whether simvastatin may increase the therapeutic effect of XRT and C225 on tumor growth in xenograft models derived from human squamous cell carcinomas. In the first instance, an in

vitro approach CDK inhibitor was undertaken to evaluate whether this statin could influence cell viability of cell cultures treated with XRT and C225. The range of doses for XRT (single dose of 2-3 Gy) and for C225 (10-30 nM) that were used in this study were based on previous reports [13] and [15], whereas the dose for simvastatin was based on dose-response preliminary results (data not shown), and data from the literature [11], and varied according to the length of each assay. We examined immediate effects of treatments by means of wound healing assay in FaDu cell line. Wound size decreased progressively, as wounds were repaired, over a 24-hour period. All treatments slowed down wound healing, but the rate of healing was lower in cultures that received simvastatin ( Table 1). At 2, 4, and 8 hours after creating the wound, we found that the presence of simvastatin

was involved in the higher inhibitory effects of the treatments, although differences were not significant. However, when the observation was extended to 24 hours, differences became more apparent and statistically significant, suggesting that inhibition of cell proliferation rather than LY2835219 molecular weight cell migration—the latter being an early event—could have been implicated in this observation. It is important to note that triple treatment with XRT, C225, and simvastatin was more cytotoxic than XRT and C225 without the statin, which indicates a potential role for simvastatin ( Table 1). To investigate

the effects of simvastatin on cell proliferation in FaDu cells, MRIP as well as in A431 cells, we subjected cell cultures to the different treatments for longer periods of time of 24, 48, and 72 hours (Table 2). In both cell lines, cell number increased as a function of time, but FaDu cells showed higher proliferation rates. Likewise, in both cell types, cell proliferation was inhibited by all the therapeutic schemes, an effect that was more obvious as time increased. For individual treatments, XRT and simvastatin alone had the highest effect. Regarding combined treatments, it is of note that the addition of C225 to XRT was not reflected in a significant decrease of proliferation although these cells were sensitive to C225 alone. On the contrary, we found that the addition of simvastatin to XRT plus C225 effectively resulted in a significant inhibition of proliferation, leading at 72 hours to a decrease of 2.7-fold for FaDu cells and 5.5-fold for A431 cells compared to XRT alone and 1.93-fold and 4.3-fold, respectively, compared to XRT and C225 (Table 2).