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IRE 1α is critical for Kaempferol‐induced neuroblastoma differentiation
Author(s) -
Abdullah Ahmad,
Talwar Priti,
d'Hellencourt Christian Lefebvre,
Ravanan Palaniyandi
Publication year - 2019
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14776
Subject(s) - neuroblastoma , microbiology and biotechnology , chemistry , biology , cell culture , genetics
Neuroblastoma is an embryonic malignancy that arises out of the neural crest cells of the sympathetic nervous system. It is the most common childhood tumor known for its spontaneous regression via the process of differentiation. The induction of differentiation using small molecules such as retinoic acid is one of the therapeutic strategies to treat the residual disease. In this study, we have reported the effect of kaempferol (KFL) in inducing differentiation of neuroblastoma cells in vitro . Treatment of neuroblastoma cells with KFL reduced the proliferation and enhanced apoptosis along with the induction of neuritogenesis. Analysis of the expression of neuron‐specific markers such as β‐ III tubulin, neuron‐specific enolase, and N‐ myc downregulated gene 1 revealed the process of differentiation accompanying KFL‐induced apoptosis. Further analysis to understand the molecular mechanism of action showed that the effect of KFL is mediated by the activation of the endoribonuclease activity of inositol‐requiring enzyme 1 alpha (IRE1α), an endoplasmic reticulum‐resident transmembrane protein. In silico docking analysis and biochemical assays using recombinant human IRE 1α confirm the binding of KFL to the ATP ‐binding site of IRE 1α, which thereby activates IRE 1α ribonuclease activity. Treatment of cells with the small molecule STF 083010, which specifically targets and inhibits the endoribonuclease activity of IRE 1α, showed reduced expression of neuron‐specific markers and curtailed neuritogenesis. The knockdown of IRE 1α using plasmid‐based sh RNA lentiviral particles also showed diminished changes in the morphology of the cells upon KFL treatment. Thus, our study suggests that KFL induces differentiation of neuroblastoma cells via the IRE 1α ‐ XBP 1 pathway.