Mitochondria-mediated intrinsic apoptotic pathway

The mitochondria-mediated intrinsic apoptotic pathway is a central mechanism of programmed cell death triggered by internal cellular stressors such as DNA damage, hypoxia, or oncogenic stress [PubMed: 17373881]. This pathway is tightly regulated by the BCL-2 family of proteins, which maintain a balance between pro-apoptotic (e.g., BAX, BAK) and anti-apoptotic (e.g., BCL-2, BCL-xL) members [NIH: PMC3108541]. When pro-apoptotic signals prevail, mitochondrial outer membrane permeabilization (MOMP) occurs, releasing cytochrome c and other factors like Smac/DIABLO into the cytoplasm [Creative Diagnostics]. Cytochrome c then binds to APAF-1 to form the apoptosome, which activates the initiator caspase-9, leading to the activation of executioner caspases and the systematic dismantling of the cell [PubMed: 11483509]. In many cancers, this pathway is suppressed through the overexpression of anti-apoptotic proteins, making it a major focus for therapeutic intervention [Frontiers in Oncology]. Drugs like venetoclax, a BH3 mimetic, specifically target and inhibit BCL-2 to restore apoptotic sensitivity in malignant cells [ResearchGate]. Conversely, excessive activation of this pathway is implicated in neurodegenerative and cardiovascular diseases, where preventing cell death is the therapeutic goal [NIH: PMC4113912]. Monitoring biomarkers such as BCL-2 levels or caspase activation is crucial for assessing treatment efficacy and patient selection [MDPI].

Other names

Mitochondrial pathway of apoptosisIntrinsic pathway of apoptosisBcl-2 regulated pathwayMitochondrial death pathway

Inhibition of anti-apoptotic BCL-2 family proteins (e.g., BCL-2, MCL-1) or activation of pro-apoptotic effectors to induce mitochondrial outer membrane permeabilization (MOMP), leading to cytochrome c release and caspase activation.