Mechanistically, SNS-032 repressed the c-Myc-dependent transcription of RhoA gene, and thereby lowered the RhoA GTPase activity and actin polymerization, and subsequently inhibited cell motility and liver metastasis.
The expression ratios to beta-actin of mRNA of thymidine synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and oroteta phosphoribosyl transferase (OPRT) were measured in primary and liver metastases of colorectal carcinomas by laser-captured microdissection and real time PCR.
The DPD, OPRT, TP, and UP mRNA levels were significantly higher in liver metastases than in primary tumor (expression in relation to that of beta-actin mRNA: 0.42 vs 0.16, P=0.00053; 1.4 vs 0.92, P=0.016; 23 vs 11, P=0.00014; 0.36 vs 0.25, P=0.0026; respectively).