Vitamin B6 based Pt(II) complexes: biomolecule derived potential cytotoxic agents for thyroid cancer.

Vitamin B6 is an essential vitamin that serves as a co-enzyme in a number of enzymatic reactions in metabolism of lipids, amino acids, and glucose. In the current study, we synthesized vitamin B6 derived ligand (L) and its complex Pt(L)Cl (C1). The ancillary chloride ligand of C1 was exchanged with pyridine co-ligand and another complex Pt(L)(py).BF4 (C2) was obtained. Both these complexes were obtained in excellent isolated yields and characterized thoroughly by different analytical methods. Thyroid cancer is one of the most common malignancies of the endocrine system, we studied the in vitro anticancer activity and mechanism of these vitamin B6 derived L and Pt(II) complexes in thyroid cancer cell line (FTC). Based on MTT assay, cell proliferation rate was reduced in a dose-dependent manner. According to apoptosis analysis, vitamin B6 based Pt(II) complexes treated cells depicted necrotic effect and TUNEL based apoptosis was observed in cancer cells. Furthermore, qRT-PCR analyses of cancer cells treated with C1 and/or C2 showed regulated expression of anti-apoptotic, pro-apoptosis and autophagy related genes. Western blot results demonstrated that C1 and C2 induced the activation of p53 and the cleavage of Poly (ADP-ribose) polymerase (PARP). These results suggest that these complexes inhibit the growth of FTC cells and induce apoptosis through p53 signaling. Thus, vitamin B6 derived Pt(II) complexes C1 and C2 may be potential cytotoxic agents for the treatment of thyroid cancer.