Fluid shear stress activates YAP to promote epithelial–mesenchymal transition in hepatocellular carcinoma

Abstract

Epithelial-mesenchymal transition (EMT) mediated by fluid shear stress (FSS) in the tumor microenvironment plays an important role in driving metastasis of the malignant tumor. As a mechanotransducer, Yes-associated protein (YAP) is known to translocate into the nucleus to initiate transcription of genes involved in cell proliferation upon extracellular biophysical stimuli.Here, we showed that FSS facilitated cytoskeleton rearrangement in hepatocellular carcinoma cells, which led to the release of YAP from its binding partner, integrin β subunit, in the cytomembrane. Moreover, we found that upregulation of GEF-H1, a microtubule-associated Rho guanine nucleotide exchange factor (GEF), is a critical step in the FSS-induced translocation of YAP. Nuclear YAP activated the expression of the EMT-regulating transcription factor SNAI1, but suppressed the expression of N6-methyladenosine (m 6 A) modulators; together, this promoted the expression of EMT-related genes. We also observed that FSS-treated HepG2 cells showed markedly increased tumorigenesis and metastasis in vivo. Collectively, our findings unravel the underlying molecular processes by which FSS induces translocation of YAP from the cytomembrane to the nucleus, contributes to EMT and enhances metastasis in hepatocellular carcinoma.

Yes-associated protein contributes to magnesium alloy-derivedinflammation in endothelial cells

“…Following the manufacturer’s instructions, blocking and chromogenic detection were performed using the DAKO Envision System with DAB substrate (DAKO Corporation). The detailed protocol is described in Yu et al [ 21 ]. The used antibodies are listed in Supplementary Table S2 .…”

“…We designed four YAP1 shRNAs target sequences, and the target sequences are listed in Supplementary Table S3 . Plasmids and YAP stably silenced HCAECs were obtained according to the methods described previously [ 21 ]. Cells were screened by Endothelial Cell Medium containing 0.5 μg/mL puromycin.…”

“…The next-generation sequencing process was performed by Aksomics, Inc (Shanghai, China) and was described previously [ 21 ]. Briefly, total RNA was harvested using Trizol reagent (Invitrogen, CA, USA) following the manufacturer’s instructions.…”

“…ChIP-qPCR was performed as described previously [ 21 ]. Briefly, per 5 μg antibody was used to target per 100 μg sheared chromatin.…”

Towards an integrative understanding of cancer mechanobiology: calcium, YAP, and microRNA under biophysical forces

“…261 In hepatocellular carcinomas, fluid shear stress (1.4 dyne cm 2 for 2–8 h) triggers the nuclear YAP translocation in a F-actin-dependent way. 262 Whether nuclear mechano-sensing and cortical actin tension are involved in this mechanism remains unclear.…”