Many factors can cause cell death. There are two primary ways cells die: necrosis and apoptosis.
Necrosis vs. Apoptosis
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Necrosis: This is cell death caused by external factors like injury, infection (bacteria, viruses, fungi), poisons, toxins, lack of blood supply (ischemia, as seen in heart attacks or strokes), or autoimmune diseases. Necrosis is often an uncontrolled process, resulting in inflammation and damage to surrounding tissues. [Reference: Cleveland Clinic, NIH Research Matters (toxin kills HIV-infected cells), Nature (platinum-containing chemotherapeutic agents)]
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Apoptosis: This is programmed cell death, a natural and controlled process essential for development and maintaining tissue health. While it can be triggered by internal cellular signals (e.g., DNA damage), external factors can also induce it. [Reference: Cleveland Clinic, Science Advances (caspase-2 kills cells)]
Other Causes of Cell Death
Beyond these two main types, other mechanisms contribute to cell death:
- Oncolytic viruses: These viruses are engineered to specifically target and kill cancer cells. They can also boost the immune system's response against tumors. [Reference: National Cancer Institute]
- Specific toxins: Some toxins selectively target and eliminate specific types of cells, such as those infected with HIV. [Reference: NIH Research Matters (toxin kills HIV-infected cells)]
- Chemotherapeutic agents: Many cancer treatments work by inducing cell death in rapidly dividing cancer cells. Different agents use various mechanisms. For example, some cause DNA damage (cisplatin, carboplatin), while others trigger different death pathways (oxaliplatin). [Reference: Nature (platinum-containing chemotherapeutic agents)]
- Proteins with detergent-like action: Certain proteins can kill bacteria within human cells by disrupting their membranes, similar to how detergents work. [Reference: NIH Research Matters (detergent-like protein kills bacteria)]
- Granzyme-induced necroptosis: This is a newly discovered pathway involved in cancer immunotherapy. [Reference: PMC (so many ways to naturally kill a cancer cell)]
- Lidocaine: This common anesthetic can kill some cancer cells by activating bitter taste receptors. [Reference: Penn Medicine]
Different cells have varying sensitivities to these death-inducing factors. The specific mechanism of cell death depends on the cause and the type of cell. The process can be complex, involving multiple pathways and interactions within the cell and its surroundings. The examples provided highlight the diverse methods by which cells meet their demise.
