(18-Crown-6)potassium(I) Trichlorido[28-acetyl-3-(tris-(hydroxylmethyl)amino-ethane)betulinic ester-κN]platinum(II): Synthesis and In Vitro Antitumor Activity

Abstract

Synthesis of platinum(II) conjugate with acetylated betulinic acid tris(hydroxymethyl)aminomethane ester (BATRIS) is presented (BATRISPt). HR-ESI-MS and multinuclear NMR spectroscopy, as well as elemental analysis were used for characterization of BATRISPt. Cytotoxicity (3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), crystal violet (CV), and sulforhodamine B (SRB) assays) of BA, BATRIS, BATRISPt, and cisplatin were assessed on seven different tumor cell lines: melanoma B16, colon HCT116 and DLD-1, adenocarcinoma HeLa, breast MCF-7, and anaplastic thyroid tumor 8505C and SW1736; as well as normal MRC-5 fibroblasts. Furthermore, the effect of the mentioned compounds on the apoptosis (Annexin V/PI assay) and autophagy induction (acridine orange (AO) assay) as well as caspase 3, 8, and 9 activation were investigated on the selected B16 melanoma cell line. BATRISPt showed lower activity than BA, BATRIS, or cisplatin. All tested compounds triggered apoptosis in B16 cells. Induction of autophagy was observed in B16 cells exposed only to BATRIS. On the other hand, new conjugate activates caspases 8 and 9 in B16 cells with higher impact than BATRIS or cisplatin alone.