Effect of dicarboxylic (C6 and C9) acids on a human squamous carcinoma cell line in cultures

In tissue culture, azelaic acid (C₉) has been shown to have an anti-proliferative and cytotoxic effect on human and murine malignant melanocytes, with inhibition of mitochondrial oxido-reductase enzymes and DNA synthesis, and damage to mitochondria. Recent reports of effects on differentiation of normal keratocytes have led to the present study of its effects on a squamous carcinoma cell line. Cells were exposed to single doses of disodium salts of azelaic (C₉2Na) and adipic (C₆2Na) acids at concentrations of 10^-2 M and 5 x 10^-2 M for 48 hrs. Only C₉2Na at 5 x 10^-2 M for 4 hrs., and longer, significantly affected proliferation, and the cells exhibited massive swelling of mitochondria with loss of cristae. The results further confirm the probable value of azelaic acid as a general anti-tumoral agent rather than a specifically melanocytotoxic one. They could justify clinical studies on the effect of topical azelaic acid therapy on squamous cell carcinoma in vivo.