The integrated stress response promotes B7H6 expression

We report that in contrast to other NK cell ligands, endoplasmic reticulum (ER) stress upregulates B7H6 mRNA levels and surface expression. B7H6 induction by ER stress requires protein kinase R-like ER kinase (PERK), one of the three canonical sensors of the unfolded protein response. PERK phosphorylates eIF2 α, which regulates protein synthesis and gene expression. Because eIF2α is phosphorylated by several kinases following different stress conditions, the program downstream to eIF2α phosphorylation is called the integrated stress response (ISR). Several drugs were reported to promote the ISR. Nelfi navir and lopinavir, two clinically approved HIV protease inhibitors, promote eIF2α phosphorylation by different mechanisms. We show that nelfinavir and lopinavir sustainably instigate B7H6 expression at their pharmacologically relevant concentrations. As such, ER stress and ISR conditions sensitiz e melanoma targets to CAR-T cells directed against B7H6. Our study highlights a novel mechanism to induce B7H6 expression and suggests a pharmacological approach to improve B7H6-directed immunotherapy.Key messagesB7H6 is induced by ER stress in a PERK-dependent mechanism.Induction of B7H6 is obtained pharmacologically by HIV protease inhibitors.Exposure of tumor cells to the HIV protease inhibitor nelfinavir improves the recognition by B7H6-directed CAR-T.
Source: Journal of Molecular Medicine - Category: Molecular Biology Source Type: research