Dear fellow researchers,
I am working on a project to globally determine the phosphorylation quantitative profiles of cisplatin-induced apoptosis in Jurkat T-cells. I have 4 biological replicates of control against 4 treated samples. These samples are then digested, performed phosphopeptide enrichment, and analyzed by LC-MS/MS. When comparing phosphoproteins in control against treated samples, the data showed that cell cycle/mitosis proteins are enriched amongst down-regulated proteins in cisplatin-treated cells. While the upregulated proteins are enriched in proteins of MAPK signaling pathway.
Since MAPK signaling pathway with three MAPK families (ERK, JNK/SAPK, and p38 MAPK) is closely associated with cell proliferation, differentiation, development, inflammation, apoptosis, and stress response.
Because this is cisplatin-induced apoptosis in Jurkat T-cells, then MAPK involved in inflammation, apoptosis, and stress response is quite expected. But so does cell cycle/mitosis.
In addition, phosphorylated transcription factor c-JUN has been found to be up-regulated in cisplatin-treated compared to control samples. The western blots results showed that both phosphorylated and un-phosphorylated versions of c-JUN were upregulated.
Un-phosphorylated c-JUN is required for maintaining sufficient cyclin D1 kinase activity and allowing cell cycle progression. While phosphorylated S63/S73 c-JUN is required for the cooperation of c-JUN with NF-κB to prevent apoptosis induced by TNFα. This means that c-JUN regulates cell cycle progression and apoptosis through two separate mechanisms. Either ways, increased expression of c-JUN is closely related to cell cycle/mitosis.
However, when comparing phosphoproteins in control against treated samples, the data showed that cell cycle/mitosis proteins are enriched amongst down-regulated proteins in cisplatin-treated cells. Does anyone know why this is the case?
Thank you so much for your help. I really appreciate it.
Without a better view of what specifically is going on in the cell cycle, it's impossible to answer your question accurately. If your data indicate that cell cycle changes are occurring with treatment, you should really do a FACS experiment with propidium iodide (PI) to directly assess the changes in cell cycle. However, I'm uncertain how your study will differentiate itself from previous work already conducted with cisplatin. See the following paper from Sanchez-Perez et al. Cisplatin induces a persistent activation of JNK that is related to cell death.
Hi Trung Tran,
In addition to what Jenny Lynn Pokorny so rightfully said, please keep in mind the pivotal role of three of kinases (cyclin-dependent kinase 7 [CDK7], Plk1, and KPCD1) in the protection against cisplatin-induced cytotoxicity. It was shown that the cellular response to cisplatin involves a variety of kinases and phosphatases not only acting in the nucleus but also regulating cytoplasmic targets, resulting in extensive cytoskeletal rearrangements. Integration of transcriptomic and proteomic data revealed a POOR correlation between changes in the relative levels of transcripts and their corresponding proteins, but rather a large overlap in affected pathways at the levels of mRNA, protein, and phosphoprotein.
Best wishes,
IlyaTsyrlov
The apoptotic direction indicated by Jenny and the anti-apoptotic direction indicated by Tsyrlov and your result on MAPKs are all right..!! Because Jurkat is known to undergo blebbishield formation (survival after commitment of apoptosis) See Figure 8g (table)
https://www.researchgate.net/publication/233742776_Blebbishields_the_Emergency_Program_for_Cancer_Stem_Cells_Sphere_Formation_and_Tumorigenesis_after_Apoptosis
The sphere formation after blebbishield formation (also called transformation) is regulated by JNKs (both positively or negatively depending on cellular context: I had put example papers below; not in Jurkat though)
http://www.jbc.org/content/274/42/29672.full
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC196007/
Hope you get the picture..
Article Blebbishields, the Emergency Program for Cancer Stem Cells: ...
- Badges
- Science topic
- Similar topics
- Medicine
- Oncology
- Cancer Research