Loss of stretch-activated channels, PIEZOs, accelerates non-small cell lung cancer progression and cell migration

Piezo1 - Serine/threonine-protein phosphatase 2A - Cofilin1 biochemical mechanotransduction axis controls F-actin dynamics and cell migration

This study sheds light on a ground-breaking biochemical mechanotransduction pathway and reveals how Piezo1 channels orchestrate cell migration. We observed an increased cell migration rate in HEK293T (HEK) cells treated with Yoda1, a Piezo1 agonist, or in HEK cells overexpressing Piezo1 (HEK + P). Conversely, a significant reduction in cell motility was observed in HEK cells treated with GsMTx4 (a channel inhibitor) or upon silencing Piezo1 (HEK-P). Our findings establish a direct correlation between alterations in cell motility, Piezo1 expression, abnormal F-actin microfilament dynamics, and the regulation of Cofilin1, a protein involved in severing F-actin microfilaments. Here, the conversion of inactive pCofilin1 to active Cofilin1, mediated by the serine/threonine-protein phosphatase 2A catalytic subunit C (PP2AC), resulted in increased severing of F-actin microfilaments and enhanced cell migration in HEK + P cells compared to HEK controls. However, this effect was negligible in HEK-P and HEK cells transfected with hsa-miR-133b, which post-transcriptionally inhibited PP2AC mRNA expression. In summary, our study suggests that Piezo1 regulates cell migration through a biochemical mechanotransduction pathway involving PP2AC-mediated Cofilin1 dephosphorylation, leading to changes in F-actin microfilament dynamics.

Pathological mechanisms of cold and mechanical stress in modulating cancer progression

Environmental temperature and cellular mechanical force are the inherent factors that participate in various biological processes and regulate cancer progress, which have been hot topics worldwide. They occupy a dominant part in the cancer tissues through different approaches. However, extensive investigation regarding pathological mechanisms in the carcinogenic field. After research, we found cold stress via two means to manipulate tumors: neuroscience and mechanically sensitive ion channels (MICHs) such as TRP families to regulate the physiological and pathological activities. Excessive cold stimulation mediated neuroscience acting on every cancer stage through the hypothalamus-pituitary-adrenocorticoid (HPA) to reach the target organs. Comparatively speaking, mechanical force via Piezo of MICHs controls cancer development. The progression of cancer depends on the internal activation of proto-oncogenes and the external tumorigenic factors; the above two means eventually lead to genetic disorders at the molecular level. This review summarizes the interaction of bidirectional communication between them and the tumor. It covers the main processes from cytoplasm to nucleus related to metastasis cascade and tumor immune escape.

Pleiotropic physiological functions of Piezo1 in human body and its effect on malignant behavior of tumors

Mechanosensitive ion channel protein 1 (Piezo1) is a large homotrimeric membrane protein. Piezo1 has various effects and plays an important and irreplaceable role in the maintenance of human life activities and homeostasis of the internal environment. In addition, recent studies have shown that Piezo1 plays a vital role in tumorigenesis, progression, malignancy and clinical prognosis. Piezo1 is involved in regulating the malignant behaviors of a variety of tumors, including cellular metabolic reprogramming, unlimited proliferation, inhibition of apoptosis, maintenance of stemness, angiogenesis, invasion and metastasis. Moreover, Piezo1 regulates tumor progression by affecting the recruitment, activation, and differentiation of multiple immune cells. Therefore, Piezo1 has excellent potential as an anti-tumor target. The article reviews the diverse physiological functions of Piezo1 in the human body and its major cellular pathways during disease development, and describes in detail the specific mechanisms by which Piezo1 affects the malignant behavior of tumors and its recent progress as a new target for tumor therapy, providing new perspectives for exploring more potential effects on physiological functions and its application in tumor therapy.

PIEZO1 regulates leader cell formation and cellular coordination during collective keratinocyte migration

The collective migration of keratinocytes during wound healing requires both the generation and transmission of mechanical forces for individual cellular locomotion and the coordination of movement across cells. Leader cells along the wound edge transmit mechanical and biochemical cues to ensuing follower cells, ensuring their coordinated direction of migration across multiple cells. Despite the observed importance of mechanical cues in leader cell formation and in controlling coordinated directionality of cell migration, the underlying biophysical mechanisms remain elusive. The mechanically-activated ion channel PIEZO1 was recently identified to play an inhibitory role during the reepithelialization of wounds. Here, through an integrative experimental and mathematical modeling approach, we elucidate PIEZO1's contributions to collective migration. Time-lapse microscopy reveals that PIEZO1 activity inhibits leader cell formation at the wound edge. To probe the relationship between PIEZO1 activity, leader cell formation and inhibition of reepithelialization, we developed an integrative 2D continuum model of wound closure that links observations at the single cell and collective cell migration scales. Through numerical simulations and subsequent experimental validation, we found that coordinated directionality plays a key role during wound closure and is inhibited by upregulated PIEZO1 activity. We propose that PIEZO1-mediated retraction suppresses leader cell formation which inhibits coordinated directionality between cells during collective migration.

Piezo1 mechanosensing regulates integrin-dependent chemotactic migration in human T cells

T cells are crucial for efficient antigen-specific immune responses and thus their migration within the body, to inflamed tissues from circulating blood or to secondary lymphoid organs, plays a very critical role. T cell extravasation in inflamed tissues depends on chemotactic cues and interaction between endothelial adhesion molecules and cellular integrins. A migrating T cell is expected to sense diverse external and membrane-intrinsic mechano-physical cues, but molecular mechanisms of such mechanosensing in cell migration are not established. We explored if the professional mechanosensor Piezo1 plays any role during integrin-dependent chemotaxis of human T cells. We found that deficiency of Piezo1 in human T cells interfered with integrin-dependent cellular motility on ICAM-1-coated surface. Piezo1 recruitment at the leading edge of moving T cells is dependent on and follows focal adhesion formation at the leading edge and local increase in membrane tension upon chemokine receptor activation. Piezo1 recruitment and activation, followed by calcium influx and calpain activation, in turn, are crucial for the integrin LFA1 (CD11a/CD18) recruitment at the leading edge of the chemotactic human T cells. Thus, we find that Piezo1 activation in response to local mechanical cues constitutes a membrane-intrinsic component of the 'outside-in' signaling in human T cells, migrating in response to chemokines, that mediates integrin recruitment to the leading edge.

Increased PIEZO1 Expression Is Associated with Worse Clinical Outcomes in Hormone-Receptor-Negative Breast Cancer Patients

PIEZO1 plays a crucial role in the human body as a mechanosensory ion channel. It has been demonstrated that PIEZO1 is important in tissue development and regulating many essential physiological processes. Studies have suggested that the PIEZO1 ion channel plays a role in invasion and progression in cancer; elevated levels of PIEZO1 have been correlated with increased migration in breast cancer cells, chemo-resistance and invasion in gastric cancer cells, and increased invasion of osteosarcoma cells. In addition, high PIEZO1 expression levels were correlated with a worse prognosis in glioma patients. On the other hand, studies in lung cancer have attributed high PIEZO1 levels to better patient outcomes. However, the clinical impact of PIEZO1 in breast cancer is not well characterized. Therefore, our goal was to determine the clinical relevance of PIEZO1 in breast cancer. An analysis of breast cancer data from The Cancer Genome Atlas (TCGA) was conducted to investigate PIEZO1 expression levels and correlation to survival, followed by validation in an independent dataset, GSE3494. We also performed gene set enrichment analysis (GSEA) and pathway enrichment analysis. We also analyzed the immune cell composition in breast tumors from TCGA through a CIBERSORT algorithm. Our results demonstrated that the PIEZO1 expression levels are higher in hormone-receptor (HR)-negative than in HR-positive cohorts. High PIEZO1 expression is correlated with a significant decrease in survival in HR-negative cohorts, especially in triple-negative breast cancer (TNBC), suggesting that PIEZO1 could be utilized as a prognostic biomarker in HR-negative breast cancer. GSEA showed that various signaling pathways associated with more invasive phenotypes and resistance to treatments, including epithelial-mesenchymal transition (EMT), hypoxia, and multiple signaling pathways, are enriched in high-PIEZO1 HR-negative tumors. Our results also demonstrated a decrease in CD8+ and CD4+ T cell infiltration in high-PIEZO1 HR-negative tumors. Further investigations are necessary to elucidate the mechanistic roles of PIEZO1 in HR-negative breast cancer.

PIEZO2 expression is an independent biomarker prognostic for gastric cancer and represents a potential therapeutic target

Gastric cancer (GC) is one of the most prevalent malignant tumors of the gastrointestinal system in the globe. The effect of PIEZO2 on the immune function and pathological features of gastric cancer remains to be explored. The Online database of cancer genes and GSE54129 have been used to analyze the clinical characteristics of PIEZO2 expression. We looked at the relationship between PIEZO2 and the immune systems of GC patients. The TIDE algorithm was used to explore the value of PIEZO2 in immunotherapy. Investigated the enrichment of PIEZO2 gene ontology and associated signal pathways using Online gene databases. The results show that overexpression of PIEZO2 was identified as an independent risk factor for patients with GC who had poor overall survival. Individuals may have a better prognosis if they had poorly differentiated GC and increased PIEZO2 expression (P < 0.05). We demonstrated a strong correlation between PIEZO2 and immune cells. The majority of immune checkpoint and immunological-related genes were associated with PIEZO2 expression. And PIEZO2 might be used as an immunotherapy target. Finally, the differential PIEZO2 genes in GC were mostly implicated in the processes of inflammation, immunological response, and tumor metastasis, according to functional analysis. PIEZO2 has a negative correlation with cell stemness and mutation levels in patients with GC and a positive correlation with immune cell infiltration and gene expression in the tumor microenvironment. These findings point to PIEZO2 as a potential new immunotherapy target of GC.

Joining forces: crosstalk between mechanosensitive PIEZO1 ion channels and integrin-mediated focal adhesions

Both integrin-mediated focal adhesions (FAs) and mechanosensitive ion channels such as PIEZO1 are critical in mechanotransduction processes that influence cell differentiation, development, and cancer. Ample evidence now exists for regulatory crosstalk between FAs and PIEZO1 channels with the molecular mechanisms underlying this process remaining unclear. However, an emerging picture is developing based on spatial crosstalk between FAs and PIEZO1 revealing a synergistic model involving the cytoskeleton, extracellular matrix (ECM) and calcium-dependent signaling. Already cell type, cell contractility, integrin subtypes and ECM composition have been shown to regulate this crosstalk, implying a highly fine-tuned relationship between these two major mechanosensing systems. In this review, we summarize the latest advances in this area, highlight the physiological implications of this crosstalk and identify gaps in our knowledge that will improve our understanding of cellular mechanosensing.

Mechanosensing Piezo channels in gastrointestinal disorders

All cells in the body are exposed to physical force in the form of tension, compression, gravity, shear stress, or pressure. Cells convert these mechanical cues into intracellular biochemical signals; this process is an inherent property of all cells and is essential for numerous cellular functions. A cell's ability to respond to force largely depends on the array of mechanical ion channels expressed on the cell surface. Altered mechanosensing impairs conscious senses, such as touch and hearing, and unconscious senses, like blood pressure regulation and gastrointestinal (GI) activity. The GI tract's ability to sense pressure changes and mechanical force is essential for regulating motility, but it also underlies pain originating in the GI tract. Recent identification of the mechanically activated ion channels Piezo1 and Piezo2 in the gut and the effects of abnormal ion channel regulation on cellular function indicate that these channels may play a pathogenic role in disease. Here, we discuss our current understanding of mechanically activated Piezo channels in the pathogenesis of pancreatic and GI diseases, including pancreatitis, diabetes mellitus, irritable bowel syndrome, GI tumors, and inflammatory bowel disease. We also describe how Piezo channels could be important targets for treating GI diseases.

Inflammation condition sensitizes Piezo1 mechanosensitive channel in mouse cerebellum astrocyte

Piezo1 mechanosensitive ion channel (MSC) plays a significant role in human physiology. Despite several research on the function and expression of Piezo1 in the nervous system, its electrophysiological properties in neuroinflammatory astrocytes remain unknown. We tested whether astrocytic neuroinflammatory state regulates Piezo1 using electrical recordings, calcium imaging, and wound healing assays on cultured astrocytes. In this study, we determined whether neuroinflammatory condition regulates astrocytic Piezo1 currents in astrocytes. First, we performed electrophysiological recordings on the mouse cerebellum astrocytes (C8-S) under lipopolysaccharide (LPS)-induced neuroinflammatory condition. We found that LPS treatment significantly increased MSC currents in C8-S. The half-maximal pressure of LPS treated MSC currents was left-shifted but the slope sensitivity was not altered by LPS treatment. LPS-induced increase of MSC currents were further augmented by Piezo1 agonist, Yoda1 but were normalized by Piezo1 inhibitor, GsMTx4. Furthermore, silencing Piezo1 in LPS treated C8-S normalized not only MSC currents but also calcium influx and cell migration velocity. Together, our results show that LPS sensitized Piezo1 channel in C8-S astrocytes. These findings will suggest that astrocytic Piezo1 is a determinant of neuroinflammation pathogenesis and may in turn become the foundation of further research into curing several neuronal illnesses and injury related inflammation of neuronal cells.

Mechanosensitive Ion Channels and Their Role in Cancer Cells

Mechanical forces are an inherent element in the world around us. The effects of their action can be observed both on the macro and molecular levels. They can also play a prominent role in the tissues and cells of animals due to the presence of mechanosensitive ion channels (MIChs) such as the Piezo and TRP families. They are essential in many physiological processes in the human body. However, their role in pathology has also been observed. Recent discoveries have highlighted the relationship between these channels and the development of malignant tumors. Multiple studies have shown that MIChs mediate the proliferation, migration, and invasion of various cancer cells via various mechanisms. This could show MIChs as new potential biomarkers in cancer detection and prognosis and interesting therapeutic targets in modern oncology. Our paper is a review of the latest literature on the role of the Piezo1 and TRP families in the molecular mechanisms of carcinogenesis in different types of cancer.

Immunoregulatory Role of the Mechanosensitive Ion Channel Piezo1 in Inflammation and Cancer

Piezo1 was originally identified as a mechanically activated, nonselective cation ion channel, with significant permeability to calcium ions, is evolutionally conserved, and is involved in the proliferation and development of various types of cells, in the context of various types of mechanical or innate stimuli. Recently, our study and work by others have reported that Piezo1 from all kinds of immune cells is involved in regulating many diseases, including infectious inflammation and cancer. This review summarizes the recent progress made in understanding the immunoregulatory role and mechanisms of the mechanical receptor Piezo1 in inflammation and cancer and provides new insight into the biological significance of Piezo1 in regulating immunity and tumors.

Piezo1 activation facilitates ovarian cancer metastasis via Hippo/YAP signaling axis

Ovarian cancer (OC) is a highly malignant cancer with great metastatic potential. Here we aimed to investigate the role of Piezo1, a gene related to the mechanical environment of the tumor, in promoting the metastasis of OC. We performed Piezo1 knockdown in A-1847 cells using small hairpin RNAs, and the cells were inoculated subcutaneously in nude mice. Piezo1 knockdown decreased the tumor growth rate of OC tumor xenografts in mice and reduced cell migration in vitro. Metastasis in the lung was also attenuated after Piezo1 knockdown as revealed by HE staining of the lung tissues, which was concomitant with downregulation of E-Cadherin and vimentin and upregulation of N-Cadherin analyzed using western blot analysis, suggesting suppressed epithelial-to-mesenchymal transition. Migration of Piezo1-knockdown cells was also analyzed for their migratory capabilities using the scratch assay. We also analyzed the key proteins in the Hippo/YAP signaling pathway using western blot after treating A-1847 and 3AO cells with a Piezo1 inducer, Yoda1. Piezo1 inducer Yoda1 activated Hippo/YAP signal in OC cells. In conclusion, Piezo1 is overexpressed in OC tissues and contributes to OC tumor growth and metastasis. Suppression of Piezo1 is a potential therapeutic strategy for OC.

Mechanosensitive Ion Channel PIEZO1 Signaling in the Hall-Marks of Cancer: Structure and Functions

Simple Summary

Tumor cells obtain various unique characteristics, which known as hallmarks of cancers, including sustained proliferative signaling, apoptosis resistance, and metastasis. These characteristics are crucial for tumor cells survival and for supporting their rapid growth. Studies have revealed that tumorigenesis is also accompanied by alteration in mechanical properties. Tumor cells could sense various mechanical forces, such as compressive force, shear stress, and portal vein pressure, which in turn could affect tumor progression. Piezo1 is a mechanically sensitive ion channel protein that can be activated mechanically, and is closely related to various diseases. Recent studies showed that Piezo1 is overexpressed in numerous tumors and is associated with poor prognosis. Furthermore, previous studies revealed that Piezo1 mediates these cancer hallmarks, and thus links up mechanical forces with tumor progression. Therefore, the discovery of Piezo1 provides a new insight for elucidating the mechanism of tumor progression under a mechanical microenvironment.

Abstract

Tumor cells alter their characteristics and behaviors during tumorigenesis. These characteristics, known as hallmarks of cancer, are crucial for supporting their rapid growth, need for energy, and adaptation to tumor microenvironment. Tumorigenesis is also accompanied by alteration in mechanical properties. Cells in tumor tissue sense mechanical signals from the tumor microenvironment, which consequently drive the acquisition of hallmarks of cancer, including sustained proliferative signaling, evading growth suppressors, apoptosis resistance, sustained angiogenesis, metastasis, and immune evasion. Piezo-type mechanosensitive ion channel component 1 (Piezo1) is a mechanically sensitive ion channel protein that can be activated mechanically and is closely related to various diseases. Recent studies showed that Piezo1 mediates tumor development through multiple mechanisms, and its overexpression is associated with poor prognosis. Therefore, the discovery of Piezo1, which links-up physical factors with biological properties, provides a new insight for elucidating the mechanism of tumor progression under a mechanical microenvironment, and suggests its potential application as a tumor marker and therapeutic target. In this review, we summarize current knowledge regarding the role of Piezo1 in regulating cancer hallmarks and the underlying molecular mechanisms. Furthermore, we discuss the potential of Piezo1 as an antitumor therapeutic target and the limitations that need to be overcome.

The interplay between physical cues and mechanosensitive ion channels in cancer metastasis

Physical cues have emerged as critical influencers of cell function during physiological processes, like development and organogenesis, and throughout pathological abnormalities, including cancer progression and fibrosis. While ion channels have been implicated in maintaining cellular homeostasis, their cell surface localization often places them among the first few molecules to sense external cues. Mechanosensitive ion channels (MICs) are especially important transducers of physical stimuli into biochemical signals. In this review, we describe how physical cues in the tumor microenvironment are sensed by MICs and contribute to cancer metastasis. First, we highlight mechanical perturbations, by both solid and fluid surroundings typically found in the tumor microenvironment and during critical stages of cancer cell dissemination from the primary tumor. Next, we describe how Piezo1/2 and transient receptor potential (TRP) channels respond to these physical cues to regulate cancer cell behavior during different stages of metastasis. We conclude by proposing alternative mechanisms of MIC activation that work in tandem with cytoskeletal components and other ion channels to bestow cells with the capacity to sense, respond and navigate through the surrounding microenvironment. Collectively, this review provides a perspective for devising treatment strategies against cancer by targeting MICs that sense aberrant physical characteristics during metastasis, the most lethal aspect of cancer.

Mechano-Sensing Channel PIEZO2 Enhances Invasive Phenotype in Triple-Negative Breast Cancer

BACKGROUND

Mechanically gated PIEZO channels lead to an influx of cations, activation of additional Ca2+ channels, and cell depolarization. This study aimed to investigate PIEZO2's role in breast cancer.

METHODS

The clinical relevance of PIEZO2 expression in breast cancer patient was analyzed in a publicly available dataset. Utilizing PIEZO2 overexpressed breast cancer cells, and in vitro and in vivo experiments were conducted.

RESULTS

High expression of PIEZO2 was correlated with a worse survival in triple-negative breast cancer (TNBC) but not in other subtypes. Increased PEIZO2 channel function was confirmed in PIEZO2 overexpressed cells after mechanical stimulation. PIEZO2 overexpressed cells showed increased motility and invasive phenotypes as well as higher expression of SNAIL and Vimentin and lower expression of E-cadherin in TNBC cells. Correspondingly, high expression of PIEZO2 was correlated with the increased expression of epithelial-mesenchymal transition (EMT)-related genes in a TNBC patient. Activated Akt signaling was observed in PIEZO2 overexpressed TNBC cells. PIEZO2 overexpressed MDA-MB-231 cells formed a significantly higher number of lung metastases after orthotopic implantation.

CONCLUSION

PIEZO2 activation led to enhanced SNAIL stabilization through Akt activation. It enhanced Vimentin and repressed E-cadherin transcription, resulting in increased metastatic potential and poor clinical outcomes in TNBC patients.

A pan-cancer analysis reveals the genetic alterations and immunotherapy of Piezo2 in human cancer

Background: Piezo2 is a transmembrane-spanning ion channel protein implicated in multiple physiological processes, including cell proliferation and angiogenesis in many cell types. However, Piezo2 was recognized as representing a double-edged sword in terms of tumor growth. The prognostic and immunotherapeutic roles of Piezo2 in pan-cancer have not been reported.

Methods: In this study, several databases available including the UCSC Xena database, HPA, TIDE, GSEA, and cBioportal were used to investigate the expression, alterations, associations with immune indicators, and prognostic roles of Piezo2 across pan-cancer. R software and Perl scripts were used to process the raw data acquired from the UCSC Xena database.

Results: Based on processed data, our results suggested that Piezo2 expression levels were tissue-dependent in different tumor tissues. Meanwhile, the survival analysis reflected that patients suffering from KIRC, LUAD, and USC with high Piezo2 expression had good OS, while those suffering from KIRP and SARC with high Piezo2 expression had poor OS. In addition, our results showed that Piezo2 expression was associated with the infiltration of CD4⁺ T memory cells, mast cells, and dendritic cells. These results suggested that Piezo2 may involve tumor progression by influencing immune infiltration or regulating immune cell function. Further analysis indicated that Piezo2 could influence TME by regulating T-cell dysfunction. We also found that gene mutation was the most common genetic alteration of Piezo2. The GSEA analysis revealed that Piezo2 was associated with calcium ion transport, the activation of the immune response, antigen processing and presentation pathways.

Conclusion: Our study showed the expression and prognostic features of Piezo2 and highlighted its associations with genetic alterations and immune signatures in pan-cancer. Moreover, we provided several novel insights for further research on the therapeutic potential of Piezo2.

Mechanosensitive Piezo channels mediate the physiological and pathophysiological changes in the respiratory system

Mechanosensitive Piezo ion channels were first reported in 2010 in a mouse neuroblastoma cell line, opening up a new field for studying the composition and function of eukaryotic mechanically activated channels. During the past decade, Piezo ion channels were identified in many species, such as bacteria, Drosophila, and mammals. In mammals, basic life activities, such as the sense of touch, proprioception, hearing, vascular development, and blood pressure regulation, depend on the activation of Piezo ion channels. Cumulative evidence suggests that Piezo ion channels play a major role in lung vascular development and function and diseases like pneumonia, pulmonary hypertension, apnea, and other lung-related diseases. In this review, we focused on studies that reported specific functions of Piezos in tissues and emphasized the physiological and pathological effects of their absence or functional mutations on the respiratory system.

A Pancancer Study of PIEZO1 as a Prognosis and Immune Biomarker of Human Tumors

PIEZO1, a mechanosensitive ion channel protein, has been identified in the correlation between several cancers. However, the systematic pancancer study of PIEZO1 still lacks. We examined PIEZO1 across thirty-three types of cancers to explore its role in prognosis and immunological function for the first time. Based on the open databases TCGA, GTEx and CPTAC, PIEZO1 has been demonstrated to be differentially expressed in most cancers compared to adjacent normal tissues. The distinct correlation between PIEZO1 and prognosis of tumor patients was explored by GEPIA2. Genetic alteration of PIEZO1 in the TCGA tumors showed that mutation is the alteration which is linked to OS, DSS, DFS and PFS in some tumors. Alterations of protein phosphorylation levels were detected in some cancers based on the CPTAC dataset. PIEZO1 expression was linked with immune cell infiltration, such as endothelial cell and cancer-associated fibroblast. Finally, KEGG and GO enrichment analyses were applied to investigate the molecular mechanism of PIEZO1. Our first pancancer analysis illustrated the roles of PIEZO1 in different types of tumors.

Store-Operated Ca2+ Entry Contributes to Piezo1-Induced Ca2+ Increase in Human Endometrial Stem Cells

Endometrial mesenchymal stem cells (eMSCs) are a specific class of stromal cells which have the capability to migrate, develop and differentiate into different types of cells such as adipocytes, osteocytes or chondrocytes. It is this unique plasticity that makes the eMSCs significant for cellular therapy and regenerative medicine. Stem cells choose their way of development by analyzing the extracellular and intracellular signals generated by a mechanical force from the microenvironment. Mechanosensitive channels are part of the cellular toolkit that feels the mechanical environment and can transduce mechanical stimuli to intracellular signaling pathways. Here, we identify previously recorded, mechanosensitive (MS), stretch-activated channels as Piezo1 proteins in the plasma membrane of eMSCs. Piezo1 activity triggered by the channel agonist Yoda1 elicits influx of Ca²⁺, a known modulator of cytoskeleton reorganization and cell motility. We found that store-operated Ca²⁺ entry (SOCE) formed by Ca²⁺-selective channel ORAI1 and Ca²⁺ sensors STIM1/STIM2 contributes to Piezo1-induced Ca²⁺ influx in eMSCs. Particularly, the Yoda1-induced increase in intracellular Ca²⁺ ([Ca²⁺]_i) is partially abolished by 2-APB, a well-known inhibitor of SOCE. Flow cytometry analysis and wound healing assay showed that long-term activation of Piezo1 or SOCE does not have a cytotoxic effect on eMSCs but suppresses their migratory capacity and the rate of cell proliferation. We propose that the Piezo1 and SOCE are both important determinants in [Ca²⁺]_i regulation, which critically affects the migratory activity of eMSCs and, therefore, could influence the regenerative potential of these cells.

Methylation silencing of ULK2 via epithelial-mesenchymal transition causes transformation to poorly differentiated gastric cancers

BACKGROUND

Diffuse-type gastric cancers (DGC) typically have a poor prognosis related to their invasion and metastasis, in which the epithelial-mesenchymal transition (EMT) is the initiation step. ULK2 plays a role in the autophagy initiation, which might provide a survival advantage in cancer cells. Although knock-down of ULK2 reportedly induces autophagy and EMT in a lung cancer cell line, the mechanism of EMT via the down-regulation of ULK2, as well as its clinical significance, remains yet unclear. The present study, therefore, aims at clarifying this mechanism and its clinical significance in gastric cancers.

METHODS

We examined ULK2 mRNA expression in gastric cancer tissues and normal gastric tissues of healthy people. The effects of knock-downed ULK2 were examined in two gastric cancer cells, which were investigated in terms of their gene expression changes by the mRNA microarray.

RESULTS

ULK2 was strongly expressed in intestinal-type cancers but was scarcely expressed in DGC by immunohistochemical staining. Furthermore, we found that ULK2 was methylated in DGC and was unmethylated in corresponding adjacent normal tissues. Then, we validated whether knock-down of ULK2 could induce autophagy, cell migration, and EMT in NUGC3 and MKN45 cells. Using mRNA microarray analysis, we confirmed that knock-down of ULK2 changed expressions of oncogenic genes associated with cell migration and EMT. Autophagy inhibitor suppressed cell migration and EMT induced by knock-down of ULK2 in NUGC3 and MKN45.

CONCLUSION

Methylation silencing of ULK2 could induce cell migration and EMT by means of autophagy induction, causing transformation to poorly differentiated cancers.

Fine-Tuning of Piezo1 Expression and Activity Ensures Efficient Myoblast Fusion during Skeletal Myogenesis

Mechanical stimuli, such as stretch and resistance training, are essential in regulating the growth and functioning of skeletal muscles. However, the molecular mechanisms involved in sensing mechanical stress during muscle formation remain unclear. Here, we investigated the role of the mechanosensitive ion channel Piezo1 during myogenic progression of both fast and slow muscle satellite cells. We found that Piezo1 level increases during myogenic differentiation and direct manipulation of Piezo1 in muscle stem cells alters the myogenic progression. Indeed, Piezo1 knockdown suppresses myoblast fusion, leading to smaller myotubes. Such an event is accompanied by significant downregulation of the fusogenic protein Myomaker. In parallel, while Piezo1 knockdown also lowers Ca²⁺ influx in response to stretch, Piezo1 activation increases Ca²⁺ influx in response to stretch and enhances myoblasts fusion. These findings may help understand molecular defects present in some muscle diseases. Our study shows that Piezo1 is essential for terminal muscle differentiation acting on myoblast fusion, suggesting that Piezo1 deregulation may have implications in muscle aging and degenerative diseases, including muscular dystrophies and neuromuscular disorders.

The mechanosensitive channel Piezo1 cooperates with semaphorins to control neural crest migration

Cells are permanently exposed to a multitude of different kinds of signals: however, how cells respond to simultaneous extracellular signals within a complex in vivo environment is poorly understood. Here, we studied the role of the mechanosensitive ion channel Piezo1 on the migration of the neural crest, a multipotent embryonic cell population. We identify that Piezo1 is required for the migration of Xenopus cephalic neural crest. We show that loss of Piezo1 promotes focal adhesion turnover and cytoskeletal dynamics by controlling Rac1 activity, leading to increased speed of migration. Moreover, overactivation of Rac1, due to Piezo1 inhibition, counteracts cell migration inhibitory signals by Semaphorin 3A and Semaphorin 3F, generating aberrant neural crest invasion in vivo. Thus, we find that, for directional migration in vivo, neural crest cells require a tight regulation of Rac1, by semaphorins and Piezo1. We reveal here that a balance between a myriad of signals through Rac1 dictates cell migration in vivo, a mechanism that is likely to be conserved in other cell migration processes.

Summary: Neural crest directional and normal migration in vivo requires both chemical and mechanical regulation of Rac1 by Semaphorin 3A and Piezo1, respectively.

Mechanosensing by Piezo1 and its implications for physiology and various pathologies

Piezo1 is a mechanosensitive ion channel with essential roles in cardiovascular, lung, urinary, and immune functions. Piezo1 is widely distributed in different tissues in the human body and its specific roles have been identified following a decade of research; however, not all are well understood. Many structural and functional characteristics of Piezo1 have been discovered and are known to differ greatly from the characteristics of other mechanosensitive ion channels. Understanding the mechanisms by which this ion channel functions may be useful in determining its physiological roles in various organ systems. This review provides insight into the signalling pathways activated by mechanical stimulation of Piezo1 in various organ systems and cell types. We discuss downstream targets of Piezo1 and the overall effects resulting from Piezo1 activation, which may provide insights into potential treatment targets for diseases involving this ion channel.

Channeling the Force: Piezo1 Mechanotransduction in Cancer Metastasis

Cancer metastasis is one of the leading causes of death worldwide, motivating research into identifying new methods of preventing cancer metastasis. Recently there has been increasing interest in understanding how cancer cells transduce mechanical forces into biochemical signals, as metastasis is a process that consists of a wide range of physical forces. For instance, the circulatory system through which disseminating cancer cells must transit is an environment characterized by variable fluid shear stress due to blood flow. Cancer cells and other cells can transduce physical stimuli into biochemical responses using the mechanosensitive ion channel Piezo1, which is activated by membrane deformations that occur when cells are exposed to physical forces. When active, Piezo1 opens, allowing for calcium flux into the cell. Calcium, as a ubiquitous second-messenger cation, is associated with many signaling pathways involved in cancer metastasis, such as angiogenesis, cell migration, intravasation, and proliferation. In this review, we discuss the roles of Piezo1 in each stage of cancer metastasis in addition to its roles in immune cell activation and cancer cell death.

Targeting ion channels for the treatment of lung cancer

Lung cancer is caused by several environmental and genetic variables and is globally associated with elevated morbidity and mortality. Among these variables, membrane-bound ion channels have a key role in regulating multiple signaling pathways in tumor cells and dysregulation of ion channel expression and function is closely related to proliferation, migration, and metastasis of lung cancer. This work reviews and summarizes current knowledge about the role of ion channels in lung cancer, focusing on the changes in the expression and function of various ion channels in lung cancer and how these changes affect lung cancer cell biology both in vitro and in vivo as evidenced by both genetic and pharmacological studies. It can help understand the molecular mechanisms of various ion channels influencing the initiation and progression of lung cancer and shed new insights into their roles in the development and treatment of this deadly disease.

Recent advances in the pathophysiology of PIEZO1-related hereditary xerocytosis

Hereditary xerocytosis is a rare red blood cell disease related to gain-of-function mutations in the FAM38A gene, encoding PIEZO1, in 90% of cases; PIEZO1 is a broadly expressed mechano-transducer that plays a major role in many cell systems and tissues that respond to mechanical stress. In erythrocytes, PIEZO1 adapts the intracellular ionic content and cell hydration status to the mechanical constraints induced by the environment. Until recently, the pathophysiology of hereditary xerocytosis was mainly believed to be based on the "PIEZO1-Gardos channel axis" in erythrocytes, according to which PIEZO1-activating mutations induce a calcium influx that secondarily activates the Gardos channel, leading to potassium and water efflux and subsequently to red blood cell dehydration. However, recent studies have demonstrated additional roles for PIEZO1 during early erythropoiesis and reticulocyte maturation, as well as roles in other tissues and cells such as lymphatic vessels, hepatocytes, macrophages and platelets that may affect the pathophysiology of the disease. These findings, presented and discussed in this review, broaden our understanding of hereditary xerocytosis beyond that of primarily being a red blood cell disease and identify potential therapeutic targets.

Physiology and Pathophysiology of Mechanically Activated PIEZO Channels

Nearly all structures in our body experience mechanical forces. At a molecular scale, these forces are detected by ion channels that function as mechanotransducers converting physical forces into electrochemical responses. Here we focus on PIEZOs, a family of mechanically activated ion channels comprising PIEZO1 and PIEZO2. The significance of these channels is highlighted by their roles in touch and pain sensation as well as in cardiovascular and respiratory physiology, among others. Moreover, mutations in PIEZOs cause somatosensory, proprioceptive, and blood disorders. The goal here is to present the diverse physiology and pathophysiology of these unique channels, discuss ongoing research and critical gaps in the field, and explore the pharmaceutical interest in targeting PIEZOs for therapeutic development.

LncRNA SENCR promotes cell proliferation and progression in non-small-cell lung cancer cells via sponging miR-1-3p

ABBREVIATION

NSCLC: Non-small cell lung cancer.

Piezo 1 activation facilitates cholangiocarcinoma metastasis via Hippo/YAP signaling axis

Tumor metastasis is one of the major factors for the high mortality in cholangiocarcinoma (CCA), but its underlying mechanisms are not fully understood. Here, we report that Piezo-type mechanosensitive ion channel component 1 (Piezo 1) is detected to be significantly upregulated in CCA tissues, which is linked to a poor prognosis in patients, suggesting that Piezo 1 may act in a pro-metastatic role in CCA development. Piezo 1 is activated through 20% simulated physiological stretch, and deleting Piezo 1 impedes epithelial-to-mesenchymal transition (EMT) of CCA cells, as well as impairing their metastatic capacity in vitro and in vivo. Mechanistically, the activation of Piezo 1 results in large amounts of Yes-associated protein 1 (YAP) translocated into the nucleus from the cytoplasm, and thus the motility of CCA cells is significantly increased. These findings indicate that mechanical stimulation induces Piezo 1 activation, which might be involved in CCA metastasis via the Hippo/YAP signaling axis. Therefore, Piezo 1 and its downstream effectors may be a novel therapeutic target for CCA treatment.

The prognostic value of Piezo1 in breast cancer patients with various clinicopathological features

The effects of piezo-type mechanosensitive ion channel component 1 (Piezo1) in sensing extracellular mechanical stress have been well investigated. Recently, Piezo1's vital role in cancerogenesis has been demonstrated by many studies. Nonetheless, the prognostic value of Piezo1 in cancer still remains unexplored and unclear. This article aims to investigate the prognostic value of Piezo1 in breast cancer. Human Protein Atlas and the Cancer Genome Atlas (TCGA) databases were used to examine Piezo1 expression in different human tissues and human cell lines. The discrepancies of Piezo1 mRNA expression in breast cancer patients with different clinicopathological features were assessed using bc-GenExMiner. The prognostic value of Piezo1 in breast cancer patients was evaluated using Kaplan-Meier plotter. Piezo1 mRNA was extensively expressed in human tissues and cell lines, particularly in breast and cancerous breast cancer cell line MCF7. High Piezo1 expression was found correlated with poor prognosis of breast cancer. Survival analysis further confirmed unfavorable prognosis of high Piezo1 expression in breast cancer patients with lymph node positive, estrogen receptor positive, Grade 2 (Scarff-Bloom-Richardson grading system), luminal A, and human epidermal growth factor receptor 2 overexpression, respectively. This study suggested that Piezo1 can serve as a prognostic indicator of breast cancer.

A New Hope in Spinal Degenerative Diseases: Piezo1

As a newly discovered mechanosensitive ion channel protein, the piezo1 protein participates in the transmission of mechanical signals on the cell membrane and plays a vital role in mammalian biomechanics. Piezo1 has attracted widespread attention since it was discovered in 2010. In recent years, studies on piezo1 have gradually increased and deepened. In addition to the discovery that piezo1 is expressed in the respiratory, cardiovascular, gastrointestinal, and urinary systems, it is also stably expressed in cells such as mesenchymal stem cells (MSCs), osteoblasts, osteoclasts, chondrocytes, and nucleus pulposus cells that constitute vertebral bodies and intervertebral discs. They can all receive external mechanical stimulation through the piezo1 protein channel to affect cell proliferation, differentiation, migration, and apoptosis to promote the occurrence and development of lumbar degenerative diseases. Through reviewing the relevant literature of piezo1 in the abovementioned cells, this paper discusses the effect of piezo1 protein expression under mechanical stress stimuli on spinal degenerative disease, providing the molecular basis for the pathological mechanism of spinal degenerative disease and also a new basis, ideas, and methods for the prevention and treatment of this degenerative disease.

YAP signaling induces PIEZO1 to promote oral squamous cell carcinoma cell proliferation

Most cancer cells are exposed to altered extracellular environments, such as an increase in extracellular matrix (ECM) stiffness and soluble signals consisting of growth factors and cytokines. It is therefore conceivable that changes in tumor extracellular environments affect tumor cell behavior. The Hippo pathway reportedly responds to the extracellular environment and regulates the nuclear localization of the transcription co-activator, yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ). Inactivation of the Hippo pathway with nuclear translocation of YAP/TAZ stimulates cell proliferation. Its pathway also regulates gene expression, but the precise molecule(s) meditating the cell-proliferating effect of YAP signaling on oral squamous cell carcinoma (OSCC) is unclear. First, we examined the effects of YAP signaling on OSCC tumorigenesis. Loss-of-function experiments using siRNA or an inhibitor, and immunohistochemical analyses of tissue specimens obtained from OSCC patients demonstrated that YAP signaling was involved in OSCC cell proliferation. Second, we identified Piezo-type mechanosensitive ion channel component 1 (PIEZO1), a Ca²⁺ channel, as a transcriptional target of YAP signaling and showed that elevated PIEZO1 was required for PIEZO1 agonist-dependent Ca²⁺ entry and cell proliferation in OSCC cells. Experiments using three-dimensional and suspension culture revealed that PIEZO1 was involved in OSCC cellular growth. Finally, YAP overexpression in the nucleus and/or cytoplasm was immunohistochemically detected in tumor lesions with frequent expression of both PIEZO1 and Ki-67, but not in non-tumor regions of OSCC specimens. These results suggest that the YAP/PIEZO1 axis promotes OSCC cell growth. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Mechanosensitive Piezo Channels in Cancer: Focus on altered Calcium Signaling in Cancer Cells and in Tumor Progression

Mechanotransduction, the translation of mechanical stimuli into biological signals, is a crucial mechanism involved in the function of fundamentally all cell types. In many solid tumors, the malignant transformation is often associated with drastic changes in cell mechanical features. Extracellular matrix stiffness, invasive growth, and cell mobility are just a few hallmarks present in cancer cells that, by inducing mechanical stimuli, create positive feedbacks promoting cancer development. Among the molecular players involved in these pathophysiological processes, the mechanosensitive Ca²⁺-permeable Piezo channels have emerged as major transducers of mechanical stress into Ca²⁺ dependent signals. Piezo channels are overexpressed in several cancers, such as in breast, gastric, and bladder, whereas their downregulation has been described in other cancers. Still, the roles of mechanosensitive Piezos in cancer are somewhat puzzling. In this review, we summarize the current knowledge on the pathophysiological roles of these Ca²⁺-permeable channels, with special emphasis on their functional involvement in different cancer types progression.

Upregulation of Piezo1 Is a Novel Prognostic Indicator in Glioma Patients

Purpose

Previous study reported that Piezo1 was highly expressed in glioma and promoted the proliferation of glioma cells, suggesting that Piezo1 overexpression might contribute to the poor prognosis of patients. Thus, this study aimed to identify whether Piezo1 may become a new prognostic biomarker for glioma patients.

Patients and Methods

Firstly, Piezo1 expression of gliomas was analyzed through GEO and Oncomine dataset, and verified by qRT-PCR and immunohistochemistry (IHC) methods. A total of 183 glioma patients were included in this study between January 2010 and December 2014. Kaplan-Meier survival analyses, Cox regression analyses and ROC curve analyses were performed to assess the diagnostic and prognostic values of Piezo1 in glioma patients.

Results

In this study, Piezo1 was identified to be highly expressed in gliomas, and increased with WHO grade. Chi-square test results showed that Piezo1 expression was significantly related to age (P=0.00), WHO grade (P=0.00), Histopathology (P=0.00), IDH1 mutation (P=0.00) and chemotherapy (P=0.00). Kaplan-Meier analysis showed that the overall survival (OS) of patients with high Piezo1 expression was significantly worse than that of patients with low Piezo1 expression (HR=3.39, 95% CI=2.40-4.81, P<0.0001). A multivariate Cox regression analysis revealed that Piezo1 might be an independent prognostic factor for glioma patients (HR=1.34, 95% CI=1.23-1.47, P=0.000). The area under the ROC curve (AUC) of 1-, 3-, and 5-year overall survival for Piezo1 overexpression was 0.820 (P=0.000), 0.849 (P=0.000), and 0.861 (P=0.000), respectively.

Conclusion

Piezo1 was overexpressed in glioma samples. Piezo1 overexpression as an independent prognostic factor adversely affects the prognosis of patients, which could be a new novel prognostic indicator in glioma patients.

The function of Piezo1 in colon cancer metastasis and its potential regulatory mechanism

OBJECTIVE

Increasing evidence has revealed that mechanical stress and elevated mechanical signals promote malignant tumor transformation and metastasis. This study aimed to explore the function of the mechanically activated ion-channel Piezo1 in the colon cancer metastasis and its potential regulatory mechanism.

METHODS

First, we examined the expression levels of Piezo1 and mitochondrial calcium uniporter (MCU) both in colon cancer tissues and assessed the prognostic value of Piezo1 and MCU in a colon cancer cohort (n = 110). Second, functional assays were performed to investigate the effects of Piezo1 and MCU on colon cancer cell migration, invasion, and mitochondrial membrane potential. Third, we analyzed the expression of Piezo1, MCU, and HIF-1α by overexpressing/silencing each other's expression.

RESULTS

We found that Piezo1 was up-regulated and MCU was down-regulated in colon cancer tissues. Piezo1 and MCU were both correlated with poor prognosis of patients with colon cancer. Overexpressing Piezo1 and silencing MCU could promote colon cancer cell migration and metastasis, reduce mitochondrial membrane potential, and promote each other's expression. We also found that HIF-1α was up-regulated in colon cancer tissues. Additionally, silencing Piezo1 inhibited the expression of HIF-1α and VEGF, which was contrary to MCU silencing. Intriguingly, Piezo1-overexpressing cells did not regain their migration behaviors when HIF-1α expression was inhibited, which was accompanied with the re-expression of MCU and VEGF.

CONCLUSION

In our study, Piezo1 is involved in colon cancer cell metastasis. Furthermore, our findings indicated a possible Piezo1-MCU-HIF-1α-VEGF axis, which still need further exploration.

Adenosine Triphosphate Release and P2 Receptor Signaling in Piezo1 Channel-Dependent Mechanoregulation

Organs and tissues and their constituent cells are physiologically submitted to diverse types of mechanical forces or stress, one common sequence of which is release of intracellular ATP into extracellular space. Extracellular ATP is a well-established autocrine or paracrine signaling molecule that regulates multiple cell functions and mediates cell-to-cell communications via activating the purinergic P2 receptors, more specifically, ligand-gated ion channel P2X receptors and some of the G-protein-coupled P2Y receptors. The molecular mechanisms that sense mechanical and transduce forces to trigger ATP release are poorly understood. The Piezo1, a newly identified mechanosensing ion channel, shows widespread expression and confers mechanosensitivity in many different types of cells. In this mini-review, we briefly introduce the Piezo1 channel and discuss the evidence that supports its important role in the mechanoregulation of diverse cell functions and, more specifically, critical engagement of ATP release and subsequent P2 receptor activation in Piezo1 channel-dependent mechanoregulation. Such ATP release-mediated coupling of the Piezo1 channel and P2 receptors may serve a signaling mechanism that is more common than we currently understand in transducing mechanical information to regulation of the attendant cell functions in various organs and tissues.

Mechanosensitive ion channels push cancer progression

In many cases, the mechanical properties of a tumor are different from those of the host tissue. Mechanical cues regulate cancer development by affecting both tumor cells and their microenvironment, by altering cell migration, proliferation, extracellular matrix remodeling and metastatic spread. Cancer cells sense mechanical stimuli such as tissue stiffness, shear stress, tissue pressure of the extracellular space (outside-in mechanosensation). These mechanical cues are transduced into a cellular response (e. g. cell migration and proliferation; inside-in mechanotransduction) or to a response affecting the microenvironment (e. g. inducing a fibrosis or building up growth-induced pressure; inside-out mechanotransduction). These processes heavily rely on mechanosensitive membrane proteins, prominently ion channels. Mechanosensitive ion channels are involved in the Ca²⁺-signaling of the tumor and stroma cells, both directly, by mediating Ca²⁺ influx (e. g. Piezo and TRP channels), or indirectly, by maintaining the electrochemical gradient necessary for Ca²⁺ influx (e. g. K_2P, K_Ca channels). This review aims to discuss the diverse roles of mechanosenstive ion channels in cancer progression, especially those involved in Ca²⁺-signaling, by pinpointing their functional relevance in tumor pathophysiology.