Nuclear MYH9-induced CTNNB1 transcription, targeted by staurosporin, promotes gastric cancer cell anoikis resistance and metastasis

Abstract

Rationale: Peritoneal metastasis predicts poor prognosis of gastric cancer (GC) patients, and the underlying mechanisms are poorly understood. Methods: The 2-DIGE, MALDI-TOF/TOF MS and single-cell transcriptome were used to detect differentially expressed proteins among normal gastric mucosa, primary GC and peritoneal metastatic tissues. Lentiviruses carrying shRNA and transcription activator-like effector nuclease technology were used to knock down myosin heavy chain 9 (MYH9) expression in GC cell lines. Immunofluorescence, immune transmission electron microscopy, chromatin fractionation, co-immunoprecipitation, and assays for chromatin immunoprecipitation, dual luciferase reporter, agarose-oligonucleotide pull-down, flow cytometry and cell anoikis were performed to uncover nuclear MYH9-induced β-catenin ( CTNNB1 ) transcription in vitro . Nude mice and conditional transgenic mice were used to investigate the findings in vivo . Results: We observed that MYH9 was upregulated in metastatic GC tissues and was associated with a poor prognosis of GC patients. Mechanistically, we confirmed that MYH9 was mainly localized in the GC cell nuclei by four potential nuclear localization signals. Nuclear MYH9 bound to the CTNNB1 promoter through its DNA-binding domain, and interacted with myosin light chain 9, β-actin and RNA polymerase II to promote CTNNB1 transcription, which conferred resistance to anoikis in GC cells in vitro and in vivo . Staurosporine reduced nuclear MYH9 S1943 phosphorylation to inhibit CTNNB1 transcription, Wnt/β-catenin signaling activation and GC progression in both orthotropic xenograft GC nude mouse and transgenic GC mouse models. Conclusion: This study identified that nuclear MYH9-induced CTNNB1 expression promotes GC metastasis, which could be inhibited by staurosporine, indicating a novel therapy for GC peritoneal metastasis.

HMGA1 stimulates MYH9-dependent ubiquitination of GSK-3β via PI3K/Akt/c-Jun signaling to promote malignant progression and chemoresistance in gliomas

“…It promotes the tumorigenesis and development of those cancers and has a positive correlation with the prognosis of patients. Recently, it was confirmed that MYH9 binds to the CTNNB1 promoter to promote CTNNB1 transcription, conferring resistance to anoikis in gastric cancer [ 17 ]. Targeting MYH9 blocked HBX-induced GSK-3β ubiquitination to activate the β-catenin destruction complex, suppressing hepatocellular cancer stemness and the epithelial-to-mesenchymal transition [ 18 ].…”

Mesenchymal stem cell-derived extracellular vesicles prevent the development of osteoarthritis via the circHIPK3/miR-124-3p/MYH9 axis

“…MYH9, a class of MYH9 gene encoding “gastric” framework-related protein, is a hexamer composed of two 220 kDa heavy chains, two 17 kDa essential light chains, and two 20 kDa regulatory light chains, widely expressed in cells and tissues [ 78 – 80 ]. MYH9 has been confirmed to have vital regulatory effects in papillary thyroid cancer [ 81 ], osteosarcoma [ 82 ], gastric cancer [ 83 ], melanoma [ 84 ] and other diseases. However, the role of MYH9 in OA remains unknown previously.…”

The MYH9 Cytoskeletal Protein Is a Novel Corepressor of Androgen Receptors

“…In the present study, although the expression of MYH9 was not significantly different between LNCaP and LNCaP-AI cells, it increased in the cytoplasm while decreased in the nucleus of LNCaP-AI cells. Nuclear MYH9 acts as a transcription factor and binds to the promoter of CTNNB1 ( 52 ), suggesting the function of nuclear MYH9 is different from the common cytoplasmic ones that acts as scaffold protein promoting cell migration and invasiveness. We speculate that increased cytoplasmic MYH9 interacts with F-actin and other cytoskeleton proteins promoting cell migration and invasiveness while decreased levels of nuclear MYH9 reduce nuclear p53 accumulation.…”