Cytoplasmic translocation of tumor suppressor HINT1 and its impact on cell shape during density transition

Cells at low density exhibit spreading and migration behaviors with more spread-out morphologies, while high-density cultures show confined, rounded morphologies. During this transition, the actin cytoskeleton rearranges from oriented stress fibers to a cortical actin shell, supporting cell movement and shape maintenance. This transition also halts cell proliferation to prevent uncontrolled growth, as seen in tumors. However, the molecular mechanism behind actin cytoskeleton remodeling by cell density is not well understood. Using proteomics of purified open chromatin, we identified the tumor suppressor HINT1 as a key molecule whose nucleocytoplasmic shuttling depends on cell density. RNA-seq analysis of wild-type (WT) and knock-out (KO) HEK293A cells revealed that HINT1 is involved in morphogensis and development. To investigate the role of HINT1, we established HINT1-KO HEK293A cells using the CRISPR-Cas9 approach and analyzed expressed mRNA using RNA-seq.