Ioulia Chatzistamou, Nikolina Dioufa, George Trimis, Alexandra Sklavounou, Christos Kittas, Hippokratis Kiaris, Athanasios G. Papavassiliou, "p21/waf1 and Smooth-Muscle Actin α Expression in Stromal Fibroblasts of Oral Cancers", Analytical Cellular Pathology, vol. 33, Article ID 824217, 8 pages, 2010. https://doi.org/10.3233/ACP-CLO-2010-0528
p21/waf1 and Smooth-Muscle Actin α Expression in Stromal Fibroblasts of Oral Cancers
Background: Concerted alterations between stromal fibroblasts and neoplastic cells underline the carcinogenic process. Activation of alpha-smooth muscle actin (SMA) expression, a cytoskeleton protein normally expressed only in myoepithelial cells, is considered a landmark for the activation of stromal fibroblasts with little however being known regarding the mechanism governing the expression of SMA in the stroma.Methods: We have evaluated by immunohistochemistry the expression of SMA in the stroma of oral malignant and pre-malignant lesions, in association with the expression of p53 and p21 tumor suppressors that were shown previously to be deregulated and/or mutated in stromal fibroblasts of various cancers. The effects of p21 knockdown in SMA expression and cell migration and the mRNA levels of endogenous p21 in fibroblasts co-cultured with cancer cells were also assessed.Results: We found that both p21 and SMA expression was elevated in the stroma, but not the epithelium, of malignant as compared to pre-malignant lesions. We also noted that the expression of both was positively correlated, implying that SMA expression may be regulated by p21. Consistently with this notion we found that siRNA-mediated p21 suppression resulted in the reduction of SMA levels and also inhibited cell migration.Conclusion: Our results show that p21 deregulation is associated with the activation of stromal fibroblasts of oral cancers by a mechanism that involves the stimulation of SMA expression.
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