Glycosylated platinum(IV) prodrugs demonstrated significant therapeutic efficacy in cancer cells and minimized side-effects

Conjugates (A1-A5) of the Pt(IV) derivative (A6) with amino groups from peracetyl glucose, rhamnose and mannose with a propyl amino or ethyl amino linker at the reducing end were synthesized and exhibited significant therapeutic efficacy in tumour cells, especially for prostate cancer (PCa). The antitumor activities are greatly affected by glycosyl groups. Cytotoxic experiments in vitro indicated that the antitumor activities were increased by 5-fold when its Pt(IV) derivative was conjugated to S18 (IC50 = 4.82 +/- 0.45 mu M) and by 12-fold when conjugated to S21 (IC50 = 1.9 +/- 0.67 mu M). The mannose substituted Pt(IV) complexes A4 and A5 were also over an order of magnitude more potent towards HeLa, A549, MCF-7 and PC3 than cisplatin and oxaliplatin. Importantly, the glycosylated Pt(IV) derivatives A4 and A5 displayed potential safety for clinical therapeutic exposure with IC50 of 84 mu M and 169 mu M compared with cisplatin (IC50 = 8 mu M) to 3T3. Cellular uptake and DNA platination are higher than cisplatin and oxaliplatin. ESI-MS analysis of A5 binding to 5'-dGMP revealed that bifunctional DNA lesions were formed. The antitumor activities in vivo showed that the MTD and LD50 for A4 and A5 are nearly 4-fold higher than that of oxaliplatin indicating the potential safety for the glycosylated Pt(IV) complexes.