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Modulation of apoptotic pathways triggered by cytotoxic agents
E Solary1, S Plenchette, O Sordet
1INSERM Unité 517, 7 boulevard Jeanne d'Arc, 21000 Dijon, France.
Abstract:
Anticancer drugs can induce tumour cell death by apoptosis. The main pathway from specific damage induced by the drug to apoptosis involves activation of caspases in the cytosol by pro-apoptotic molecules such as cytochrome c released from the mitochondria. At least in some cell types, anticancer drugs also upregulate the expression of death receptors and sensitize tumour cells to their cognate ligands, which could be used to amplify the response to cytotoxic drugs. The Bcl-2 family of proteins, which includes anti- and pro-apoptotic molecules, regulates cell sensitivity at the mitochondrial level. Chemotherapeutic drugs modulate their expression (e.g. through p53-dependent gene transcription), their activity (e.g. by phosphorylation) and their subcellular localization (e.g. by translocation of pro-apoptotic proteins from the cytosol to the mitochondria). When interacting with tumour cells, anticancer drugs also activate lipid- and kinase-dependent signalling pathways that modulate the death response to specific damage. Protective pathways include activation of NF kappa B transcription factor, accumulation of heat shock proteins and activation of proteins involved in cell cycle regulation. The recent identification on these pathways to cell death has suggested several new strategies to improve the therapeutic efficacy of currently used anticancer drug regimens.
Insights
Anticancer drugs trigger tumor cell death via apoptosis, involving caspase activation and modulation of cell death pathways. Understanding these mechanisms offers new strategies to enhance chemotherapy effectiveness.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Anticancer drugs induce tumor cell death primarily through apoptosis.
- Key pathways involve caspase activation, mitochondrial cytochrome c release, and death receptor signaling.
- The Bcl-2 protein family critically regulates apoptosis sensitivity at the mitochondrial level.
Purpose of the Study:
- To elucidate the molecular mechanisms by which anticancer drugs induce apoptosis.
- To explore how anticancer drugs modulate cell death pathways, including death receptors and Bcl-2 family proteins.
- To identify novel strategies for improving anticancer drug efficacy based on identified pathways.
Main Methods:
- Analysis of caspase activation pathways.
- Investigation of mitochondrial outer membrane permeabilization.
- Assessment of death receptor and ligand interactions.
- Modulation of Bcl-2 family protein expression and localization.
- Examination of lipid- and kinase-dependent signaling pathways.
- Identification of protective pathways such as NF-kappa B activation.
Main Results:
- Anticancer drugs activate caspases via cytochrome c release from mitochondria.
- Drug-induced apoptosis can be amplified by upregulating death receptors.
- Bcl-2 family proteins are modulated by chemotherapeutic drugs at transcriptional, post-translational, and localization levels.
- Signaling pathways involving lipids and kinases influence the response to anticancer drugs.
- Protective mechanisms like NF-kappa B activation and heat shock proteins counteract drug-induced death.
Conclusions:
- Anticancer drugs induce apoptosis through complex molecular pathways involving mitochondria, death receptors, and signaling cascades.
- Modulation of Bcl-2 family proteins and signaling pathways represents a key mechanism of action for chemotherapeutic agents.
- Targeting these identified cell death and survival pathways holds promise for developing more effective anticancer therapies.