Abstract 17: hiPSCs-derived <i>PTEN</i> deletion suppresses cardiomyocyte differentiation and beating

Abstract Human-induced pluripotent stem cells (hiPSCs) have been increasingly used for cardiac tissue engineering and cell-based therapies for heart regeneration because they possess self-renewal capability in vitro and can differentiate into most cardiovascular cell types, including cardiomyocytes. The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a potent tumor suppressor frequently being deficient in human cancer. It is also important for cardiac functions and embryonic development since the loss of PTEN induced embryonic lethality; however, the underlying mechanisms are not fully understood. Here, to understand the function of PTEN in cardiomyocyte differentiation, we generated PTEN deletion in hiPSCs by using CRISPR/Cas9 system. PTEN ablation suppressed cardiomyocyte differentiation, which was shown by decreases in cardiac markers cTNT and Myh6 compared with PTEN WT. Immunofluorescence staining and flow cytometry analysis using α-actinin and cTNT supported the suppression of cardiomyocyte differentiation induced by PTEN-/- hiPSCs. q-PCR analysis was performed using representative markers for differentiation steps including mesoderm, cardiac mesoderm, cardiac progenitor, and cardiomyocyte. PTEN-/- hiPSC decreased mesoderm markers (Brachyury, Dkk1, Fox C1) on the 2nd day of differentiation, suggesting that PTEN is important for early cardiac differentiation. Western blot analysis revealed that Gsk3β and mTOR phosphorylation levels were increased due to an activation of Akt, which may involve PTEN-/--induced mesoderm abnormality. In addition, PTEN deletion also inhibited cardiac beating capability, which may explain PTEN-/--induced embryonic lethality. Citation Format: Thang Huu Nguyen, Chaeyong Jung, Sang Wook Park, Seung-Rock Lee. hiPSCs-derived PTEN deletion suppresses cardiomyocyte differentiation and beating [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 17.