Going past the data for temozolomide

Synthesis and antiproliferative activity of 3-(2-chloroethyl)-5-methyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazepin-4-(3H)-one

Based on the encouraging results found for 3,5-dimethyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazepin-4-(3H)-one 7 previously tested by us, as well as the consideration that heterocycle fused tetrazepinones bearing the 2-chloroethyl substituent show a better cytotoxic profile than temozolomide and mitozolomide against human cancer cell lines which express the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT), in this paper we report the multistep synthesis and the biological study of 3-(2-chloroethyl)-5-methyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazepin-4-(3H)-one 10. Like compound 7, it was active on P-glycoprotein expressing cells (MDR) HL60 and on K562 cell line that are resistant to apoptosis induced by different stimuli, showing GI50 values of 14 and 18 μM respectively. As an antiproliferative agent against the above cells compound 10 was about 2.2 times more active than compound 7. Compound 10 was also tested against WiDR cells which are overexpressing the DNA repair protein MGMT, showing a GI50 value of 2.3 μM. Finally, concerning the effect on cell cycle we observed an evident difference between compounds 7 and 10. In fact, compound 7 induces a block of cell cycle in G0-G1, therefore acting as phase-specific drug, in contrast, compound 10 is a not phase-specific agent. Both the compounds are able to increase the apoptotic sub G0-G1 peak of cell cycle.

Molecular analysis of a recurrent glioblastoma treated with bevacizumab

We treated a case of recurrent glioblastoma (GBM) with bevacizumab and assessed its effect biologically. A 55-year-old man with a left frontal lobe GBM was experiencing recurrence 7 months postoperation. We administered bevacizumab concomitant with temozolomide (TMZ). Follow-up magnetic resonance imaging (MRI) showed dramatic but temporal tumor reduction; however, the patient died of re-recurrent disease 6 months after beginning bevacizumab. We obtained an autopsy and analyzed the detailed molecular change. In the autopsy specimen, the quantity of microvessels was significantly reduced. Vascular endothelial growth factor receptor (VEGFR) 1 and VEGFR2 were downregulated, most likely due to a negative feedback mechanism by blocking of VEGF signaling. Matrix metalloproteinase (MMP)-2 and membrane-type 1 MMP were upregulated, resulting in the higher activation of MMP-2 in the autopsy specimen. MIB-1 staining index and phosphorylation levels of p44/42-mitogen-activated protein kinase did not change, whereas phosphorylated protein kinase B (Akt) was decreased in the autopsy specimen, suggesting compensation and/or amplification of other proliferative signaling pathways such as suppression of apoptosis signaling. Consequently, bevacizumab might inhibit the VEGF autocrine loop, which then causes a change in molecular expression related not only to enhancement of tumor invasion but also maintenance of tumor proliferation.