Dear All,
I need explanation to a result of PCR and westren bolt analyses
-a compound showed cytotoxicity,
-upregulated caspase 3 determined by PCR
-but upon using westren blot to quantify caspases 8 and 9 , both of them were less than the negative control
So, is it possible that caspase 3 is upregulated , but the initiators caspases 8 and 9 did not and also is it possible the culture treated with the test compound showed less expression for these caspases than the negative control
Dear Nahed El-Sayed,
The scenario you described is indeed possible and could be explained by the complex regulatory mechanisms involved in the activation of caspases in apoptosis. According to the established model of caspase-dependent apoptosis, caspase-3 protein cleaves and activates caspases 6 and 7 and the protein itself is processed and activated by caspases 8, 9, and 10. If caspase 3 is upregulated as determined by PCR, it suggests that there is an increased transcription or mRNA expression of caspase 3. This means that the cell is attempting to produce more caspase 3 protein. As I mentioned above, caspase 8 and 9 are initiator caspases that are typically upstream of caspase 3 in the apoptosis pathways. In some cases, downregulation of initiator caspases can occur. This might seem counterintuitive, but it can be a regulatory mechanism. In certain situations, cells might respond to cytotoxic stress by downregulating initiator caspases like caspase 8 and 9. This downregulation could be a result of feedback mechanisms designed to limit the initiation of apoptosis. Cells might try to save energy and resources by reducing the activation of upstream initiator caspases if they sense that the apoptotic process is not proceeding effectively.
In summary, the upregulation of caspase 3 alongside the downregulation of caspases 8 and 9 is consistent with a complex cellular response to cytotoxicity. It's indicative of a scenario where the cell is trying to execute apoptosis (caspase 3 upregulation) but might be modulating the initiation steps (caspases 8 and 9) for regulatory or adaptive reasons. This demonstrates the intricate and context-dependent nature of apoptotic signaling pathways.
Recommended articles:
Article Caspase-8 and Caspase-9 Functioned Differently at Different ...
Article The role of caspase-8, caspase-9, and apoptosis inducing fac...
Article Caspase-9, caspase-3 and caspase-7 have distinct roles durin...
Article Caspase-3 and caspase-8 expression in breast cancer: caspase...
Article Paradoxical roles of caspase-3 in regulating cell survival, ...
Article Cellular Mechanisms Controlling Caspase Activation and Function
Article Caspase activation, inhibition, and reactivation: A mechanistic view
https://www.nature.com/articles/cdd200929
Best regards,
Jakub Knurek
- Badges
- Science topic
- Similar topics
- Microbiology
- Assays