{Reference Type}: Journal Article {Title}: INPP4B suppresses HER2-induced mesenchymal transition in HER2+ breast cancer and enhances sensitivity to Lapatinib. {Author}: Qu N;Wang G;Su Y;Chen B;Zhou D;Wu Y;Yuan L;Yin M;Liu M;Peng Y;Zhou W; {Journal}: Biochem Pharmacol {Volume}: 226 {Issue}: 0 {Year}: 2024 08 7 {Factor}: 6.1 {DOI}: 10.1016/j.bcp.2024.116347 {Abstract}: Human epidermal growth factor receptor 2 positive (HER2+) breast cancer (BC) tends to metastasize and has a bad prognosis due to its high malignancy and rapid progression. Inositol polyphosphate 4-phosphatase isoenzymes type II (INPP4B) plays unequal roles in the development of various cancers. However, the function of INPP4B in HER2+ BC has not been elucidated. Here we found that INPP4B expression was significantly lower in HER2+ BC and positively correlated with the prognosis by bioinformatics and tissue immunofluorescence analyses. Overexpression of INPP4B inhibited cell proliferation, migration, and growth of xenografts in HER2+ BC cells. Conversely, depletion of INPP4B reversed these effects and activated the PDK1/AKT and Wnt/β-catenin signaling pathways to promote epithelial-mesenchymal transition (EMT) progression. Moreover, INPP4B overexpression blocked epidermal growth factor (EGF) -induced cell proliferation, migration and EMT progression, whereas INPP4B depletion antagonized HER2 depletion in reduction of cell proliferation and migration of HER2+ BC cells. Additionally, Lapatinib (LAP) inhibited HER2+ BC cell survival, proliferation and migration, and its effect was further enhanced by overexpression of INPP4B. In summary, our results illustrate that INPP4B suppresses HER2+ BC growth, migration and EMT, and its expression level affects patient outcome, further providing new insights into clinical practice.