Immunohistochemical evidences of anticancer actions of metformin with other repurposed drug combinations and correlation with hamster fibrosarcoma tumor size

Abstract

The aim was to detect and correlate anticancer effects of metformin in combinations with other repurposed drugs, already registered for other indications, which may be immediately applied and clinically investigated in oncology, reducing the time and cost of research for new cancer treatments. Immunohistochemistry was performed for tumors treated by dual drug combinations containing metformin with deoxycholic acid, caffeine, itraconazole, nitroglycerin, disulfiram or diclofenac. The drugs were applied in Syrian golden hamsters (6 animals per group) with inoculated BHK21/C13 fibrosarcoma in doses equivalent to usual human doses, <50 % LD50. The anticancer effects were assessed by: p53 (mutational status); Ki-67 and PCNA (tumor proliferation); CD34 and CD31 (neoangiogenesis); GLUT1 (glucose metabolism); iNOS (NO metabolism); COX4, Cytochrome C and caspase 3 (apoptosis); immunohistochemical markers. Also, biophysical characteristics of fibrosarcoma, animal blood samples and the toxicity on main organs were analyzed. Treatments significantly (P<0.05) reduced mutational status, tumor proliferation, neoangiogenesis, glucose metabolism, NO metabolism and modulated apoptosis, in correlation with tumor size, without toxicity and influence on biochemical blood and hematological tests. Administration of metformin in two-drug combination with deoxycholic acid, caffeine, itraconazole, nitroglycerin, disulfiram or diclofenac may be recommended for further clinical investigations in oncology.