Purpose: Simvastatin (Sim) is approved as lipid-controlling drug in patients with cardiovascular risk to reduce hypercholesterolemia. Recent publications indicate possible inhibitory effects of Sim on tumor cell lines, and epidemiological data suggest activity in cancer patients. Still, its therapeutic efficacy, particularly in head and neck squamous cell carcinoma (HNSCC), remains to be elucidated. This study analyzes the effects of Sim on HNSCC cell lines (KB, HN5, FaDu) and on a larger set of primary HNSCC cells by employing a short-time ex vivo colony formation test (FLAVINO assay). Possible additive or synergistic effects of Sim combinations with established chemotherapeutics are determined as well.
Methods: Biopsies of 49 HNSCC were tested in the FLAVINO assay with Sim alone or in combination with cisplatin (Cis) or docetaxel (DTX). Cell lines were studied for reference. Epithelial HNSCC cells were stained by Cy2-labeled anti-cytokeratin antibodies facilitating the detection of colony formation (CF) by immunofluorescence. Drug combinations were analyzed regarding their interaction.
Results: Sim alone acted suppressive on tested cell lines and increased the cytostatic efficacy of Cis and DTX. 18/49 HNSCC qualified for FLAVINO-based dose-response analyses, and Sim significantly suppressed CF in 18/18 primary HNSCC. Moreover, Sim increased cytotoxic effects of Cis and DTX, primarily in an additive mode of action.
Conclusions: The ex vivo tumor cell inhibition of Sim and its additive effects upon combination with established cytostatics provide the basis for epidemiological and clinical studies on statins, potentially directed toward co-medication in future treatment regimens.