Gold (I) N-heterocyclic carbene complex inhibits mouse melanoma growth by p53 upregulation

Abstract

BackgroundCancer treatment using gold (I) complexes is becoming popular. In this study, a gold (I) N-heterocyclic complex designated as complex 3 was synthesized, its cytotoxicity was examined, and its anti-melanoma activity was evaluated in vitro and in vivo.MethodsViability of cancer cells was determined by MTT assay upon treatment with various concentrations of a gold (I) N-heterocyclic carbene complex (complex 3) in a dose and time dependent manner. Mouse melanoma cells B16F10 were selected for further apoptotic studies, including flowcytometric analysis of annexin binding, cell cycle arrest, intracellular ROS generation and loss in the mitochondrial membrane potential. ELISA based assays were done for caspase activities and western blots for determining the expression of various survival and apoptotic proteins. Immunocytology was performed to visualize the translocation of p53 to the nucleus. B16F10 cells were inoculated into mice and post tumor formation, complex 3 was administered. Immunohistology was performed to determine the expressions of p53, p21, NF-κB (p65 and p50), MMP-9 and VEGF. Student’s t test was used for determining statistical significance. The survival rate data were analyzed by Kaplan-Meier plots.ResultsComplex 3 markedly inhibited the growth of HCT 116, HepG2, and A549, and induced apoptosis in B16F10 cells with nuclear condensation, DNA fragmentation, externalization of phosphatidylserine, activation of caspase 3 and caspase 9, PARP cleavage, downregulation of Bcl-2, upregulation of Bax, cytosolic cytochrome c elevation, ROS generation, and mitochondrial membrane potential loss indicating the involvement of an intrinsic mitochondrial death pathway. Further, upregulation of p53, p-p53 (ser 15) and p21 indicated the role of p53 in complex 3 mediated apoptosis. The complex reduced tumor size, and caused upregulation of p53 and p21 along with downregulation of NF-κB (p65 and p50), VEGF and MMP-9. These results suggest that it induced anti-melanoma effect in vitro and in vivo by modulating p53 and other apoptotic factors.ConclusionsThe gold (I) N-heterocyclic carbene complex (C22H26N6AuO2PF6) designated as complex 3 induced ROS and p53 dependent apoptosis in B16F10 cells involving the mitochondrial death pathway along with suppression of melanoma tumor growth by regulating the levels of pro and anti apoptotic factors (p53, p21, NF-κB, VEGF and MMP-9).

The effect of 1:2 Ag(I) thiocyanate complexes in MCF-7 breast cancer cells

“…This indicates that the silver compounds may mediate cell cycle arrest at the G2/M phase. It has been shown that other metal complexes, including gold and platinum complexes cause cell cycle arrest at the G2/M phase (Gatti et al 2002;Nandy et al 2014). Platinum compounds damage tumors via induction of apoptosis and this effect is related to inhibition of DNA synthesis and repair that might result in cell cycle arrest at the G0/G1, S or G2/M phase, therefore inducing apoptosis (Florea and Büsselberg 2011).…”

Apoptotic effects of dipyrido [3,2-a:2′,3′-c] phenazine (dppz) Au(III) complex against diethylnitrosamine/phenobarbital induced experimental hepatocarcinogenesis in rats

“…These new gold(III) compounds seem to stimulate a potent downregulation of the antiapoptotic Bcl-2 molecule and an upregulation of the proapoptotic Bax protein [10]. Similarly, Nandy et al [51] have reported that gold(I) N-heterocyclic carbene complex induced downregulation of Bcl-2, upregulation of Bax. Our results show that no significant difference of Bax levels was found between group IV and group I.…”

N‐Heterocyclic carbenes derived from imidazo‐[1,5‐a]pyridines related to natural products: synthesis, structure and potential biological activity of some corresponding gold(I) and silver(I) complexes

“…may dramatically enhance the cytotoxicity (mean IC 50 < 0.1 μM) and tumour selectivity, as was recently reported by our group. [37] Related gold-NHC complexes derived from imidazo[1,5-a]pyridine derivatives [38] Even though similar silver(I)-NHC complexes based on the imidazo[1,5-a]pyridine moiety have not been studied so far, silver (I) acetate NHC complexes derived from the imidazole [20] /benzimidazole core [39] have been tested as anticancer agents. The imidazole complexes inhibit the growth of tumour cell lines, with preference for ovarian (OVCAR-3), breast (MCF-7) and colon (HT-29) carcinomas with IC 50 values of around 10 μM, while the benzimidazole complexes have activity against the renal cancer cell line Caki-1, with IC 50 values in the range 5.4-25 μM.…”