Anticancer properties of novel pyrazole-containing biguanide derivatives with activating the adenosine monophosphate-activated protein kinase signaling pathway.

Biguanides, including metformin and phenformin, have emerged as promising anticancer agents. However, the high dose needed for their efficient anticancer properties restricts their clinical application. In an attempt to obtain higher active compounds than these parent compounds, pyrazole-containing biguanide derivatives were synthesized and screened for in vitro cytotoxicity against human cancer cell lines. Clonogenic assays and scratch wound healing assays demonstrated that these new derivatives profoundly inhibit cell proliferation and migration. Compounds 10b and 10d exhibited strong potency with low IC50 values in the range of 6.9-28.3 μM, far superior to phenformin and metformin. Moreover, 20 μM 10b and 10d resulted in 72.3-88.2% (p < 0.001) inhibition of colony formation and 29.3-60.7% (p < 0.05) inhibition of cell migration. Mechanistically, 10b and 10d activated adenosine monophosphate-activated protein kinase, leading to inactivation of the mammalian target of rapamycin (mTOR) signaling pathway with the regulation of 4EBP1 and p70S6K. These results suggest the value of these novel biguanide derivatives as candidates with therapeutic potential for the treatment of bladder and ovarian cancer.