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Triple‐negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, which is characterized by high heterogeneity and metabolic dysregulation. Inositol monophosphatase 1(IMPA1) is critical for the metabolism of inositol, which has profound effects on gene expression and other biological processes. Here, we report for the first time that IMPA1 was upregulated in TNBC cell lines and tissues, and enhanced cell colony formation and proliferation in vitro and tumorigenicity in vivo. Additionally, IMPA1 promoted cell motility in vitro and metastatic lung colonization in vivo. Mechanistic investigations by transcriptome sequencing revealed that 4782 genes were differentially expressed between cells with IMPA1 knockdown and control cells. Among the differentially expressed genes after IMPA1 knockdown, five significantly altered genes were verified via qRT‐PCR assays. Morerover, we found that the expression profile of those five targets as a gene set was significantly associated with IMPA1 status in TNBC cells. As this gene set was associated with mTOR pathway and epithelial‐mesenchymal transition (EMT) process, we further confirmed that IMPA1 induced mTOR activity and EMT process, which at least in part contributed to IMPA1‐induced TNBC progression. Collectively, our findings reveal a previously unrecognized role of IMPA1 in TNBC progression and identify IMPA1 as a potential target for TNBC therapy. [ABSTRACT FROM AUTHOR]

Previous microarray studies in our laboratory identified a number of genes that were differentially expressed in “silver” eels after transfer from freshwater (FW) to seawater (SW). A group of genes, which are related to the synthesis, processing, and transport of certain known osmolytes in mammalian cells, have been identified. One gene implicated with osmolyte production is myo-inositol monophosphatase (IMPA1). The aim of this study was to compare the expression of IMPA1 in the major osmoregulatory tissues (intestine, gill, and kidney) as fish move between FW and SW environments. No difference in IMPA1 gene expression was observed in any tissues 6 h after eel transfer to SW; however, after 2 days acclimation, a 1.9- and a 2.5-fold increase in mRNA expression was found in kidney and gill, respectively. These elevated levels were maintained for up to 5 months (4.9- and 3.4-fold, respectively) after SW transfer. No IMPA1 mRNA expression was detected in the intestine. Western blot analysis confirmed the IMPA1 protein was upregulated in the gill, but no changes in protein abundance were detected in the kidney 5 months after SW transfer. Our studies have revealed a potential role for IMPA1 in salinity adaptation in the European eel. [ABSTRACT FROM AUTHOR]