ER stress sensor PERK drives tumor-promoting myelopoiesis by reprogramming hematopoietic progenitor cells in the spleen
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ABSTRACT: The spleen, as the prominent site for extramedullary myelopoiesis in cancer, generates significant amounts of myeloid cells to promote tumor progression. Cancer-associated splenic myelopoiesis is mediated by a population of functionally distinct hematopoietic stem/progenitor cells (HSPCs) that are committed to immunosuppressive myeloid cell generation, but the molecular mechanism regulating this response remains unclear. Here, we found that HSPCs in the spleen of tumor-bearing mice exhibited accelerated protein synthesis and engaged in a robust endoplasmic reticulum (ER) stress response. Single-cell RNA sequencing showed that the ER stress response was concomitant with the myeloid-biased lineage commitment and dysfunction of HSPCs in the spleen. PKR-like ER resident kinase (PERK), a molecular sensor of ER stress, directed HSPC differentiation into myeloid-derived suppressor cells (MDSCs) via PERK–eIF2α–ATF4–C/EBPβ signaling. Inhibition of this signaling prevented the emergence of granulocyte/macrophage colony-stimulating factor-expressing HSPCs in the spleen and disrupted the positive feedback-driven splenic myelopoiesis. Consequently, a blockade of PERK abated the suppressive function of tumor-infiltrating MDSCs and increased cytotoxic T cell infiltration, reshaping the tumor microenvironment to effectively suppress disease progression and potentiate both immuno- and targeted therapies. In accordance, activation of PERK–ATF4–C/EBPβ signaling was indispensable for the differentiation of human umbilical cord blood-derived HSPCs into functionally competent MDSCs. Together, these results indicate a crucial role for the cellular ER stress sensor PERK in modulating splenic HSPC activities in cancer, suggesting novel therapeutic opportunities for targeting the tumor-promoting myeloid response at its source. Raw data are available on Genome Sequence Archive, Bioproject accession number: PRJCA003519
ORGANISM(S): Mus musculus
PROVIDER: GSE158486 | GEO | 2022/03/04
REPOSITORIES: GEO
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