Asymmetrically substituted cationic porphyrins inhibit tumor proliferation in small intestinal neuroendocrine tumors and medullary thyroid carcinomas

In this study we demonstrate anticancer activity of novel fully water soluble cationic porphyrins. The two cationic porphyrins 5,10,15-tris(N-methylpyridinium-4-yl)-20-[1-phenyl-4-(3-Nphenylsulfonylindolyl)]- 21H,23H-porphyrin chloride (TMPy3PhenIndolprot1P-Cl3) and 5-{5-[2-(9,9- Dimethyl)fluorenyl]-N-methylpyridinium-3-yl}-10,15,20-tris(N-methyl-pyridinium-4-yl)-21H,23Hporphyrin chloride (TMPy3PyFluorenyl1P-Cl4) were prepared and their antiproliferative effects were studied in two human tumor cell lines and a normal human fibroblast cell line. Effects of the novel porphyrin compounds were evaluated in the small intestinal neuroendocrine tumor cell line KRJ-I, the medullary thyroid carcinoma cell line MTC-SK and the normal human fibroblast cell line HF-SAR by cell counting, mitochondrial activity assays and cell cytotoxicity analyses. TMPy3PhenIndolprot1P-Cl3 and TMPy3PyFluorenyl1P-Cl4 showed antiproliferative effects in the tumor cell lines MTC-SK and KRJ-I; mitochondrial activity was decreased and cytotoxic effects were observed, while no significant alterations of the human fibroblasts were noted. With the advantage of full water solubility and antiproliferative effects in tumor cell lines, the novel porphyrin compounds TMPy3PhenIndolprot1P-Cl3 and TMPy3PyFluorenyl1P-Cl4 could be a new therapeutic option in anticancer treatment.