Autor: |
Leah Persaud, Jason Mighty, Xuelin Zhong, Ashleigh Francis, Marifer Mendez, Hilal Muharam, Stephen M. Redenti, Dibash Das, Bertal Huseyin Aktas, Moira Sauane |
Jazyk: |
angličtina |
Rok vydání: |
2018 |
Předmět: |
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Zdroj: |
International Journal of Molecular Sciences, Vol 19, Iss 11, p 3561 (2018) |
Druh dokumentu: |
article |
ISSN: |
1422-0067 |
DOI: |
10.3390/ijms19113561 |
Popis: |
Interleukin 24 (IL-24) is a tumor-suppressing protein, which inhibits angiogenesis and induces cancer cell-specific apoptosis. We have shown that IL-24 regulates apoptosis through phosphorylated eukaryotic initiation factor 2 alpha (eIF2α) during endoplasmic reticulum (ER) stress in cancer. Although multiple stresses converge on eIF2α phosphorylation, the cellular outcome is not always the same. In particular, ER stress-induced apoptosis is primarily regulated through the extent of eIF2α phosphorylation and activating transcription factor 4 (ATF4) action. Our studies show for the first time that cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) activation is required for IL-24-induced cell death in a variety of breast cancer cell lines and this event increases ATF4 activity. We demonstrate an undocumented role for PKA in regulating IL-24-induced cell death, whereby PKA stimulates phosphorylation of p38 mitogen-activated protein kinase and upregulates extrinsic apoptotic factors of the Fas/FasL signaling pathway and death receptor 4 expression. We also demonstrate that phosphorylation and nuclear import of tumor suppressor TP53 occurs downstream of IL-24-mediated PKA activation. These discoveries provide the first mechanistic insights into the function of PKA as a key regulator of the extrinsic pathway, ER stress, and TP53 activation triggered by IL-24. |
Databáze: |
Directory of Open Access Journals |
Externí odkaz: |
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