Bimetallic titanocene-gold phosphane complexes inhibit invasion, metastasis, and angiogenesis-associated signaling molecules in renal cancer

摘要

Following promising recentin?vitroandin?vivostudies of the anticancer efficacies of heterometallic titanocene–gold chemotherapeutic candidates against renal cancer, we report here on the synthesis, characterization, stability studies and biological evaluation of a new titanocene complex containing a gold-triethylphosphane fragment [(η-C5H5)2TiMe(μ-mba)Au(PEt3)] (4) Titanofin. The compound is more stable in physiological fluid than those previously reported, and it is highly cytotoxic against a line of human clear cell renal carcinoma. We describe here preliminary mechanistic data for this compound and previously reported [(η-C5H5)2TiMe(μ-mba)Au(PPh3)] (2) Titanocref which displayed remarkable activity in anin?vivomouse model. Mechanistic studies were carried out in the human clear cell renal carcinoma Caki-1 line for the bimetallic compounds [(η-C5H5)2TiMe(μ-mba)Au(PR3)] (PR3?=?PPh32Titanocref and PEt34Titanofin), the two monometallic gold derivatives [Au(Hmba)(PR3)] (PR3?=?PPh31cref; PEt33fin), titanocene dichloride and Auranofin as controls. These studies indicate that bimetallic compounds Titanocref (2) and Titanofin (4) are more cytotoxic than gold monometallic derivatives (1and3) and significantly more cytotoxic than titanocene dichloride while being quite selective. Titanocref (2) and Titanofin (4) inhibit migration, invasion, and angiogenic assembly along with molecular markers associated with these processes such as prometastatic IL(s), MMP(s), TNF-α, and proangiogenic VEGF, FGF-basic. The bimetallic compounds also strongly inhibit the mitochondrial protein TrxR often overexpressed in cancer cells evading apoptosis and also inhibit FOXC2, PECAM-1, and HIF-1α whose overexpression is linked to resistance to genotoxic chemotherapy. In summary, bimetallic titanocene-gold phosphane complexes (Titanocref2and Titanofin4) are very promising candidates for further preclinical evaluations for the treatment of renal cancer.