Indole-3-carbinol -: Induced growth inhibition can be converted to a cytotoxic response in the presence of TPA+Ca2+ in squamous cell carcinoma cell lines

We examined the possibility that 13C, when combined with a differentiation stimulus (TPA + CaCl2), would sensitise SCC cells to a differentiation stimulus. We report that 13C induces a profound growth inhibition in SCC cells that is dissimilar to the growth inhibition required to initiate differentiation. Moreover, we report that 13C, when combined with TPA + CaCl2 treatment, induces a loss of colony forming ability that was differentiation and senescence - independent but was due to delayed cytotoxicity. This study shows that 13C in combination with a PKC activator + Ca2+ may be a useful therapeutic strategy for treating oral SCC. (c) 2007 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.