Apoptosis induction in human breast cancer (MCF-7) cells by a novel venom l-amino acid oxidase (Rusvinoxidase) is independent of its enzymatic activity and is accompanied by caspase-7 activation and reactive oxygen species production

摘要: We report the elucidation of a mechanism apoptosis induction in breast cancer (MCF-7) cells by an L-amino acid oxidase (LAAO), Rusvinoxidase, purified from venom Daboia russelii russelii. Peptide mass fingerprinting analysis acidic monomeric glycoprotein with ~57 kDa, confirmed its identity as snake LAAO. The enzymatic activity Rusvinoxidase was completely abolished after two cycles freezing and thawing; however, cytotoxicity toward MCF-7 remained unaffected. Dose- time-dependent on evident changes cell morphology, membrane integrity, shrinkage apoptotic body formation accompanied DNA fragmentation. induced both extrinsic (death-receptor) intrinsic (mitochondrial) signaling pathways. former pathway operated through activation caspase-8 that subsequently activated caspase-7 but not caspase-3. Rusvinoxidase-induced depolarization mitochondrial generation reactive oxygen species, followed decrease cellular glutathione content catalase activity, down-regulation expression anti-apoptotic proteins Bcl-XL heat-shock (HSP-90 HSP-70). treatment resulted increase pro-apoptotic protein Bax, leading to release cytochrome c mitochondria cytosol activating caspase-9, which turn stimulated effector caspase-7. at dose 4 mg/kg non-toxic mice, indicating it may be useful model for development peptide-based anticancer drugs.