Mechanosensitive channel Piezo1 induces cell apoptosis in pancreatic cancer by ultrasound with microbubbles

Mechanical stretch promotes the neutrophil recruitment potential of fibroblasts through the Piezo/NFAT1/LIF axis

The entheses are the sites where tendons or ligaments insert into osseous structures and play a crucial role in transmitting mechanical stress from muscles to bones. Under excessive mechanical loads, the entheses may sustain inflammation, leading to isolated enthesitis. However, the specific mechanisms through which enthesitis occurs have not yet been fully elucidated. In our study, we discovered that mechanical stress is a critical factor that drives fibroblasts to recruit neutrophils through the secretion of leukemia inhibitory factor (LIF). Further research revealed that fibroblasts convert mechanical stress, a physical signal, into a chemical signal through the Piezo mechanosensitive ion channel, subsequently activating the transcription factor NFAT1 and upregulating LIF expression. This study not only helps elucidate the mechanisms underlying the development of enthesitis but also offers potential insights into the clinical management and treatment of patients with enthesitis.

Advanced Strategies for Ultrasound Control and Applications in Sonogenetics and Gas Vesicle-Based Technologies: A Review

Control systems play an important role in the diagnosis and treatment of medicine. In contrast to light and magnetic fields, ultrasound has received much attention due to its non-invasive, cost-effective, convenient, and high spatiotemporal precision and deep-penetration characteristics. Some studies have developed special nanomaterials for therapy by controlling the production of reactive oxygen species through ultrasound irradiation. However, the complex functionalities and toxicity issues associated with these nanomaterials limit the development of ultrasound control systems. To overcome these challenges, ultrasound control systems based on synthetic biology have been developed, especially for sonogenetics and gas vesicles. The tunable thermal and mechanical effects of ultrasound act as the main triggering source, enabling engineered cells to perform sono-thermal or sono-mechanical genetic modifications in the targeted tissue. Based on an in-depth understanding of the relationship between ultrasound effects and the design, composition, and applications of engineered cellular technologies, in this review, we focus on recent activation strategies of ultrasound for sonogenetics and gas vesicles, including sono-thermal promoter switch, sono-thermal transient receptor potential channel, sono-mechanical activation and gas vesicles. In addition, applications of these advanced ultrasound control systems for cancer therapy, neural activity, visual recovery and functional imaging are presented. Finally, we discuss the current challenges faced and provide an outlook on the future developments in this evolving field.

Disrupting Cdc42 activation-driven filopodia formation with low-intensity ultrasound and microbubbles: A novel strategy to block ovarian cancer metastasis

Metastasis is a primary cause of mortality and treatment failure in ovarian cancer, with limited effective therapeutic strategies. Low-intensity ultrasound (LIUS) and microbubbles (MBs) has been demonstrated as an adjunctive technique capable of enhancing drug delivery and suppressing tumor metastasis. However, the underlying mechanisms remain incompletely understood. In this study, we aimed to investigate whether LIUS + MBs alone could suppress tumor metastasis and to explore its mechanism of action through disruption of the cytoskeletal remodeling in filopodia, an essential structure in the early stages of cancer cell dissemination. Based on cell-based experiments to determine the optimal parameters, our results showed LIUS + MBs significantly inhibited the migration and invasion of ovarian cancer cells. In vivo, LIUS + MBs treatment markedly suppressed the overall metastasis in the orthotopic ovarian cancer model, and in both the intraperitoneal and hematogenous metastatic models established by injecting pretreated cells. Morphologically, such treatment led to a notable reduction in the length and number of filopodia, while the number of lamellipodia remained unaffected. At the molecular level, LIUS + MBs disturbed filopodia formation and the metastatic potential of ovarian cancer cells by suppressing the activation of Cdc42, a key regulator of cytoskeletal dynamics. The inhibitory effect was reversed by the overexpression of Cdc42CA. Further proteomic and bioinformatics analysis implied that LIUS + MBs may reduce Cdc42 activity by upregulating the expression of GTPase-activating proteins (GAPs). Our research provides novel insight into the mechanism by which LIUS + MBs can inhibit tumor metastasis, highlighting its role in disturbing the Cdc42-mediated cytoskeletal remodelling of filopodia.

Comprehensive analysis of mRNA expression of Piezo1 and Piezo2 in tumor samples and their prognostic implications in gastric cancer

BACKGROUND

This study aims to investigate the expression pattern and clinical significance of Piezo1 and Piezo2 in various cancers, focusing on gastric cancer (GC).

METHODS

The study investigated the mRNA expression levels of Piezo1 and Piezo2 in tumor samples from different cancers using the BEST online database. The case-control studies about the relation between Piezo1 and Piezo2 and GC were retrieved from PubMed, Embase, Web of Science, and Cochrane Library. The retrieval time was from inception to October, 2023. The meta-analysis of the included literatures was conducted by the STATA 12.0 software. Additionally, the expression profiles of Piezo1 and Piezo2 in tumor and normal gastric tissues were analyzed, and their clinical drug relevance was assessed using the CPADS database. The research program has been registered with PROSPERO (CRD42023495836).

RESULTS

The analysis demonstrated elevated mRNA expression of both Piezo1 and Piezo2 in the majority of tumor samples. Of particular note was the significant increase observed in GC tissue compared to normal tissue (all p < 0.05). Additionally, the meta-analysis revealed a meaningful correlation between high expression levels of Piezo1 and Piezo2 and poor prognosis in patients with GC (HR = 1.48, 95% CI = 1.27-1.69, p < 0.0001). This study identified a significant correlation between high levels of Piezo1 expression and the TNM phase (OR = 1.87, 95% CI = 1.21-2.91, p = 0.005). Furthermore, enhanced Piezo2 expression was observed to be positively correlated with survival status (OR = 2.12, 95% CI = 1.31-3.44, p = 0.002). Piezo1 (p = 0.028, R2 = 0.12) and Piezo2 (p = 0.049, R2 = 0.09) have been identified as potential therapeutic targets for GC treatment, according to drug sensitivity analyses.

CONCLUSION

The findings of this study indicate that the expression levels of Piezo1 and Piezo2 have the potential to serve as diagnostic indicators or therapeutic targets for GC management.

TRIAL REGISTRATION

CRD42023495836 (PROSPERO).

Inhibition of autophagy promotes ultrasound‑targeted microbubble destruction-induced apoptosis of pancreatic cancer cells

In therapeutic studies of pancreatic cancer, ultrasound-targeted microbubble destruction (UTMD) has shown potential in promoting apoptosis as a safe and non-invasive adjuvant therapy. Autophagy, a regulatory mechanism for cellular stress response and survival, plays a dual role in tumor development, progression, and treatment. However, the role of autophagy in UTMD-induced apoptosis in pancreatic cancer cells remains unclear. In this study, chloroquine (CQ), an autophagy inhibitor, was combined with UTMD to treat pancreatic cancer both in vitro and in vivo, with changes in apoptosis assessed through Western blot and TUNEL staining. The results showed that UTMD induced both apoptosis and autophagy in pancreatic cancer cells. Notably, inhibiting autophagy significantly enhanced UTMD-induced apoptosis, while the inhibition of apoptosis did not affect UTMD-induced autophagy. These findings suggest that autophagy reduces the effectiveness of UTMD in treating pancreatic cancer. This study offers a new perspective on UTMD for treating pancreatic cancer, suggesting that combining autophagy inhibitors could be a promising strategy to enhance the effectiveness of pancreatic cancer therapy.

Low-Intensity Pulsed Ultrasound Dynamically Modulates the Migration of BV2 Microglia

OBJECTIVE

Low-intensity pulsed ultrasound (LIPUS) is a promising modality for neuromodulation. Microglia are the resident immune cells in the brain and their mobility is critical for maintaining brain homeostasis and alleviating neuroimmune pathologies. However, it is unclear whether and how LIPUS modulates microglial migration in physiological conditions.

METHODS

Here we examined the in vitro effects of LIPUS on the mobility of BV2 microglia by live cell imaging. Single-cell tracing of BV2 microglia migration was analyzed using ImageJ and Chemotaxis and Migration Tool software. Pharmacological manipulation was performed to determine the key molecular players involved in regulating ultrasound-dependent microglia migration.

RESULTS

We found that the distance of microglial migration was enhanced by LIPUS with increasing acoustic pressure. Removing the extracellular Ca2+ influx or depletion of intracellular Ca2+ stores suppressed ultrasound-enhanced BV2 migration. Furthermore, we found that blocking the reorganization of actin, or suppressing purinergic signaling by application of apyrase or hemi-channel inhibitors, both diminished ultrasound-induced BV2 migration. LIPUS stimulation also enhanced microglial migration in a lipopolysaccharide (LPS)-induced inflammatory environment.

CONCLUSION

LIPUS promoted microglia migration in both physiological and inflammatory environments. Calcium, cytoskeleton, and purinergic signaling were involved in regulating ultrasound-dependent microglial mobility. Our study reveals the biomechanical impact of ultrasound on microglial migration and highlights the potential of using ultrasound-based tools for modulation of microglial function.

Precise modulation of cell activity using sono-responsive nano-transducers

Ultrasound, as a form of mechanical energy, possesses a distinctive ability to deeply penetrate tissues, allowing for non-invasive manipulation of cellular activities. Utilizing nanomaterials in conjunction with ultrasound has enabled simple, efficient, spatiotemporally controllable, and minimally invasive regulation of cellular activities with ultrasound-generated electric, optical, acoustic, or chemical stimuli at the localized nanomaterials interface. This technology allows for precise and localized regulation of cellular activities, which is essential for studying and understanding complex biological processes, and also provides new opportunities for research, diagnostics, and therapeutics in the fields of biology and medicine. In this article, we review the state-of-the-art and ongoing developments in nanomaterials-enabled ultrasound cellular modulation, highlighting potential applications and advancements achieved through the integration of sono-responsive nanomaterials with ultrasound.

Unveiling the potential of biomechanics in pioneering innovative strategies for cancer therapy

Mechanical force transmission is pivotal in tumor biology, profoundly affecting cancer cell behaviors such as proliferation, metastasis, and resistance to therapy. To explore novel biomechanical-based therapeutic strategies for cancer treatment, this paper deciphers the advances in biomechanical measurement approaches and the impact of biomechanical signals on fundamental oncological processes such as tumor microenvironment remodeling, angiogenesis, metastasis, and drug resistance. Then, the mechanisms of biomechanical signal transduction of tumor cells are demonstrated to identify novel targets for tumor therapy. Additionally, this study proposes a novel tumor treatment strategy, the biomechanical regulation tumor nanotherapeutics, including smart biomaterials designed to disturb mechanical signaling pathways and innovative nanodrugs that interfere transduction of biomechanical signals to improve tumor therapeutic outcomes. These methods mark a departure from conventional pharmacological therapies to novel strategies that utilize mechanical forces to impede tumor progression and enhance tumor responsiveness to treatment. In general, this review highlights the critical role of biomechanical signals in cancer biology from a holistic perspective and underscores the potential of biomechanical interventions as a transformative class of therapeutics. By integrating mechanobiology into the development of cancer treatments, this paper paves the way for more precise and effective strategies that leverage the inherent physical properties of the tumor microenvironment.

Reversible Ca2+ signaling and enhanced paracellular transport in endothelial monolayer induced by acoustic bubbles and targeted microbeads

Ultrasound and microbubble mediated blood brain barrier opening is a non-invasive and effective technique for drug delivery to targeted brain region. However, the exact mechanisms are not fully resolved. The influences of Ca2+ signaling on sonoporation and endothelial tight junctional regulation affect the efficiency and biosafety of the technique. Therefore, an improved understanding of how ultrasound evokes Ca2+ signaling in the brain endothelial monolayer, and its correlation to endothelial permeability change is necessary. Here, we examined the effects of SonoVue microbubbles or integrin-targeted microbeads on ultrasound induced bioeffects in brain microvascular endothelial monolayer using an acoustically-coupled microscopy system, where focused ultrasound exposure and real-time recording of Ca2+ signaling and membrane perforation were performed. Microbubbles induced robust Ca2+ responses, often accompanied by cell poration, while ultrasound with microbeads elicited reversible Ca2+ response without membrane poration. At the conditions evoking reversible Ca2+ signaling, intracellular Ca2+ release and reactive oxygen species played key roles for microbubbles induced Ca2+ signaling while activation of mechanosensitive ion channels was essential for the case of microbeads. Trans-well diffusion analysis revealed significantly higher trans-endothelial transport of 70 kDa FITC-dextran for both integrin-targeted microbeads and microbubbles compared to the control group. Further immunofluorescence staining showed disruption of cell junctions with microbubble stimulation and reversible remodeling of many cell junctions by ultrasound with integrin-targeted microbeads. This investigation provides new insights for ultrasound induced Ca2+ signaling and its influence on endothelial permeability, which may help develop new strategies for safe and efficient drug/gene delivery in the vascular system.

Piezo1 facilitates the initiation and progression of renal fibrosis by mediating cell apoptosis and mitochondrial dysfunction

Renal fibrosis is the major pathological changes of Chronic kidney disease (CKD). Piezo1, a mechanical sensitive ion channel, is implicated in organ fibrosis. However, the precise role of Piezo1 in CKD fibrosis is unknown. The aims of this study were to identify that the role of Piezo1 in CKD fibrosis and its potential involvement of mitochondrial dysfunction. We performed the study with the Piezo1 agonist Yoda1, Bax inhibitor BAI1, Piezo1 inhibitor GsMTx4 and detected the injury, fibrosis, apoptosis markers and mitochondrial dysfunction. The results showed that the levels of apoptosis, mitochondrial dysfunction, injury and fibrosis increased in TCMK-1 cells after treatment with Yoda1. However, these changes that induced by Yoda1 were relieved by BAI1. Similarly, inhibition Piezo1 with GsMTx4 also partly relieved the renal injury, renal fibrosis, apoptosis and mitochondrial dysfunction in vivo and vitro. In conclusion, we found Piezo1 promoted the initiation and development of renal fibrosis and inhibiting Piezo1 improved the fibrosis.

Mechanosensitive Ion Channels Piezo1 and Piezo2 Mediate Motor Responses In Vivo During Transcranial Focused Ultrasound Stimulation of the Rodent Cerebral Motor Cortex

OBJECTIVE

Transcranial focused ultrasound (tFUS) neuromodulation offers a noninvasive, safe, deep brain stimulation with high precision, presenting potential in understanding neural circuits and treating brain disorders. This in vivo study investigated the mechanism of tFUS in activating the opening of the mechanosensitive ion channels Piezo1 and Piezo2 in the mouse motor cortex to induce motor responses.

METHODS

Piezo1 and Piezo2 were knocked down separately in the mouse motor cortex, followed by EMG and motor cortex immunofluorescence comparisons before and after knockdown under tFUS stimulation.

RESULTS

The results demonstrated that the stimulation-induced motor response success rates in Piezo knockdown mice were lower compared to the control group (Piezo1 knockdown: 57.63% ± 14.62%, Piezo2 knockdown: 73.71% ± 13.10%, Control mice: 85.69% ± 10.23%). Both Piezo1 and Piezo2 knockdowns showed prolonged motor response times (Piezo1 knockdown: 0.62 ± 0.19 s, Piezo2 knockdown: 0.60 ± 0.13 s, Control mice: 0.44 ± 0.12 s) compared to controls. Additionally, Piezo knockdown animals subjected to tFUS showed reduced immunofluorescent c-Fos expression in the target area when measured in terms of cells per unit area compared to the control group.

CONCLUSION

This in vivo study confirms the pivotal role of Piezo channels in tFUS-induced neuromodulation, highlighting their influence on motor response efficacy and timing.

SIGNIFICANCE

This study provides insights into the mechanistic underpinnings of noninvasive brain stimulation techniques and opens avenues for developing targeted therapies for neural disorders.

Recent advancement of sonogenetics: A promising noninvasive cellular manipulation by ultrasound

Recent advancements in biomedical research have underscored the importance of noninvasive cellular manipulation techniques. Sonogenetics, a method that uses genetic engineering to produce ultrasound-sensitive proteins in target cells, is gaining prominence along with optogenetics, electrogenetics, and magnetogenetics. Upon stimulation with ultrasound, these proteins trigger a cascade of cellular activities and functions. Unlike traditional ultrasound modalities, sonogenetics offers enhanced spatial selectivity, improving precision and safety in disease treatment. This technology broadens the scope of non-surgical interventions across a wide range of clinical research and therapeutic applications, including neuromodulation, oncologic treatments, stem cell therapy, and beyond. Although current literature predominantly emphasizes ultrasonic neuromodulation, this review offers a comprehensive exploration of sonogenetics. We discuss ultrasound properties, the specific ultrasound-sensitive proteins employed in sonogenetics, and the technique's potential in managing conditions such as neurological disorders, cancer, and ophthalmic diseases, and in stem cell therapies. Our objective is to stimulate fresh perspectives for further research in this promising field.

Tumor perfusion enhancement by microbubbles ultrasonic cavitation reduces tumor glycolysis metabolism and alleviate tumor acidosis

The tumor microenvironment is increasingly acknowledged as a critical contributor to cancer progression, mediating genetic and epigenetic alterations. Beyond diverse cellular interactions from the microenvironment, physicochemical factors such as tumor acidosis also significantly affect cancer dynamics. Recent research has highlighted that tumor acidosis facilitates invasion, immune escape, metastasis, and resistance to therapies. Thus, noninvasive measurement of tumor acidity and the development of targeted interventions represent promising strategies in oncology. Techniques like contrast-enhanced ultrasound (CEUS) can effectively assess blood perfusion, while ultrasound-stimulated microbubble cavitation (USMC) has proven to enhance tumor blood perfusion. We therefore aimed to determine whether CEUS assesses tumor acidity and whether USMC treatment can modulate tumor acidity. Firstly, we tracked CEUS perfusion parameters in MCF7 tumor models and compared them with in vivo tumor pH recorded by pH microsensors. We found that the peak intensity and area under curve of tumor contrast-enhanced ultrasound correlated well with tumor pH. We further conducted USMC treatment on MCF7 tumor-bearing mice, tracked changes of tumor blood perfusion and tumor pH in different perfusion regions before and after the USMC treatment to assess its impact on tumor acidity and optimize therapeutic ultrasound pressure. We discovered that USMC with 1.0 Mpa significantly improved tumor blood perfusion and tumor pH. Furthermore, tumor vascular pathology and PGI2 assays indicated that improved tumor perfusion was mainly due to vasodilation rather than angiogenesis. More importantly, analysis of glycolysis-related metabolites and enzymes demonstrated USMC treatment can reduce tumor acidity by reducing tumor glycolysis. These findings support that CEUS may serve as a potential biomarker to assess tumor acidity and USMC is a promising therapeutic modality for reducing tumor acidosis.

Reverse engineering morphogenesis through Bayesian optimization of physics-based models

Morphogenetic programs coordinate cell signaling and mechanical interactions to shape organs. In systems and synthetic biology, a key challenge is determining optimal cellular interactions for predicting organ shape, size, and function. Physics-based models defining the subcellular force distribution facilitate this, but it is challenging to calibrate parameters in these models from data. To solve this inverse problem, we created a Bayesian optimization framework to determine the optimal cellular force distribution such that the predicted organ shapes match the experimentally observed organ shapes. This integrative framework employs Gaussian Process Regression, a non-parametric kernel-based probabilistic machine learning modeling paradigm, to learn the mapping functions relating to the morphogenetic programs that maintain the final organ shape. We calibrated and tested the method on Drosophila wing imaginal discs to study mechanisms that regulate epithelial processes ranging from development to cancer. The parameter estimation framework successfully infers the underlying changes in core parameters needed to match simulation data with imaging data of wing discs perturbed with collagenase. The computational pipeline identifies distinct parameter sets mimicking wild-type shapes. It enables a global sensitivity analysis to support the regulation of actomyosin contractility and basal ECM stiffness to generate and maintain the curved shape of the wing imaginal disc. The optimization framework, combined with experimental imaging, identified that Piezo, a mechanosensitive ion channel, impacts fold formation by regulating the apical-basal balance of actomyosin contractility and elasticity of ECM. This workflow is extensible toward reverse-engineering morphogenesis across organ systems and for real-time control of complex multicellular systems.

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.

Molecular mechanisms in regulation of autophagy and apoptosis in view of epigenetic regulation of genes and involvement of liquid-liquid phase separation

Cellular physiology is critically regulated by multiple signaling nexuses, among which cell death mechanisms play crucial roles in controlling the homeostatic landscape at the tissue level within an organism. Apoptosis, also known as programmed cell death, can be induced by external and internal stimuli directing the cells to commit suicide in unfavourable conditions. In contrast, stress conditions like nutrient deprivation, infection and hypoxia trigger autophagy, which is lysosome-mediated processing of damaged cellular organelle for recycling of the degraded products, including amino acids. Apparently, apoptosis and autophagy both are catabolic and tumor-suppressive pathways; apoptosis is essential during development and cancer cell death, while autophagy promotes cell survival under stress. Moreover, autophagy plays dual role during cancer development and progression by facilitating the survival of cancer cells under stressed conditions and inducing death in extreme adversity. Despite having two different molecular mechanisms, both apoptosis and autophagy are interconnected by several crosslinking intermediates. Epigenetic modifications, such as DNA methylation, post-translational modification of histone tails, and miRNA play a pivotal role in regulating genes involved in both autophagy and apoptosis. Both autophagic and apoptotic genes can undergo various epigenetic modifications and promote or inhibit these processes under normal and cancerous conditions. Epigenetic modifiers are uniquely important in controlling the signaling pathways regulating autophagy and apoptosis. Therefore, these epigenetic modifiers of both autophagic and apoptotic genes can act as novel therapeutic targets against cancers. Additionally, liquid-liquid phase separation (LLPS) also modulates the aggregation of misfolded proteins and provokes autophagy in the cytosolic environment. This review deals with the molecular mechanisms of both autophagy and apoptosis including crosstalk between them; emphasizing epigenetic regulation, involvement of LLPS therein, and possible therapeutic approaches against cancers.

Low-Frequency Ultrasound Sensitive Piezo1 Channels Regulate Keloid-Related Characteristics of Fibroblasts

Keloids are benign fibroproliferative tumors that severely diminish the quality of life due to discomfort, dysfunction, and disfigurement. Recently, ultrasound technology as a noninvasive adjuvant therapy is developed to optimize treatment protocols. However, the biophysical mechanisms have not yet been fully elucidated. Here, it is proposed that piezo-type mechanosensitive ion channel component 1 (Piezo1) plays an important role in low-frequency sonophoresis (LFS) induced mechanical transduction pathways that trigger downstream cellular signaling processes. It is demonstrated that patient-derived primary keloid fibroblasts (PKF), NIH 3T3, and HFF-1 cell migration are inhibited, and PKF apoptosis is significantly increased by LFS stimulation. And the effects of LFS is diminished by the application of GsMTx-4, the selective inhibitor of Piezo1, and the knockdown of Piezo1. More importantly, the effects of LFS can be imitated by Yoda1, an agonist of Piezo1 channels. Establishing a patient-derived xenograft keloid implantation mouse model further verified these results, as LFS significantly decreased the volume and weight of the keloids. Moreover, blocking the Piezo1 channel impaired the effectiveness of LFS treatment. These results suggest that LFS inhibits the malignant characteristics of keloids by activating the Piezo1 channel, thus providing a theoretical basis for improving the clinical treatment of keloids.

Application of calcium overload-based ion interference therapy in tumor treatment: strategies, outcomes, and prospects

Low selectivity and tumor drug resistance are the main hinderances to conventional radiotherapy and chemotherapy against tumor. Ion interference therapy is an innovative anti-tumor strategy that has been recently reported to induce metabolic disorders and inhibit proliferation of tumor cells by reordering bioactive ions within the tumor cells. Calcium cation (Ca2+) are indispensable for all physiological activities of cells. In particular, calcium overload, characterized by the abnormal intracellular Ca2+ accumulation, causes irreversible cell death. Consequently, calcium overload-based ion interference therapy has the potential to overcome resistance to traditional tumor treatment strategies and holds promise for clinical application. In this review, we 1) Summed up the current strategies employed in this therapy; 2) Described the outcome of tumor cell death resulting from this therapy; 3) Discussed its potential application in synergistic therapy with immunotherapy.

Enhanced macromolecular substance extravasation through the blood-brain barrier via acoustic bubble-cell interactions

The blood-brain barrier (BBB) maintains brain homeostasis, regulates influx and efflux transport, and provides protection to the brain tissue. Ultrasound (US) and microbubble (MB)-mediated blood-brain barrier opening is an effective and safe technique for drug delivery in-vitro and in-vivo. However, the exact mechanism underlying this technique is still not fully elucidated. The aim of the study is to explore the contribution of transcytosis in the BBB transient opening using an in-vitro model of BBB. Utilizing a diverse set of techniques, including Ca2+ imaging, electron microscopy, and electrophysiological recordings, our results showed that the combined use of US and MBs triggers membrane deformation within the endothelial cell membrane, a phenomenon primarily observed in the US + MBs group. This deformation facilitates the vesicles transportation of 500 kDa fluorescent Dextran via dynamin-/caveolae-/clathrin- mediated transcytosis pathway. Simultaneously, we observed increase of cytosolic Ca2+ concentration, which is related with increased permeability of the 500 kDa fluorescent Dextran in-vitro. This was found to be associated with the Ca2+-protein kinase C (PKC) signaling pathway. The insights provided by the acoustically-mediated interaction between the microbubbles and the cells delineate potential mechanisms for macromolecular substance permeability.

A multicellular brain spheroid model for studying the mechanisms and bioeffects of ultrasound-enhanced drug penetration beyond the blood‒brain barrier

The blood‒brain barrier (BBB) acts as a hindrance to drug therapy reaching the brain. With an increasing incidence of neurovascular diseases and brain cancer metastases, there is a need for an ideal in vitro model to develop novel methodologies for enhancing drug delivery to the brain. Here, we established a multicellular human brain spheroid model that mimics the BBB both architecturally and functionally. Within the spheroids, endothelial cells and pericytes localized to the periphery, while neurons, astrocytes, and microglia were distributed throughout. Ultrasound-targeted microbubble cavitation (UTMC) is a novel noninvasive technology for enhancing endothelial drug permeability. We utilized our three-dimensional (3D) model to study the feasibility and mechanisms regulating UTMC-induced hyperpermeability. UTMC caused a significant increase in the penetration of 10 kDa Texas red dextran (TRD) into the spheroids, 100 µm beyond the BBB, without compromising cell viability. This hyperpermeability was dependent on UTMC-induced calcium (Ca2+) influx and endothelial nitric oxide synthase (eNOS) activation. Our 3D brain spheroid model, with its intact and functional BBB, offers a valuable platform for studying the bioeffects of UTMC, including effects occurring spatially distant from the endothelial barrier.

The roles of FHL2 in cancer

LIM domain protein 2, also known as LIM protein FHL2, is a member of the LIM-only family. Due to its LIM domain protein characteristics, FHL2 is capable of interacting with various proteins and plays a crucial role in regulating gene expression, cell growth, and signal transduction in muscle and cardiac tissue. In recent years, mounting evidence has indicated that the FHLs protein family is closely associated with the development and occurrence of human tumors. On the one hand, FHL2 acts as a tumor suppressor by down-regulating in tumor tissue and effectively inhibiting tumor development by limiting cell proliferation. On the other hand, FHL2 serves as an oncoprotein by up-regulating in tumor tissue and binding to multiple transcription factors to suppress cell apoptosis, stimulate cell proliferation and migration, and promote tumor progression. Therefore, FHL2 is considered a double-edged sword in tumors with independent and complex functions. This article reviews the role of FHL2 in tumor occurrence and development, discusses FHL2 interaction with other proteins and transcription factors, and its involvement in multiple cell signaling pathways. Finally, the clinical significance of FHL2 as a potential target in tumor therapy is examined.

Mechanosensitive Ion Channels: Their Physiological Importance and Potential Key Role in Cancer

Mechanosensitive ion channels comprise a broad group of proteins that sense mechanical extracellular and intracellular changes, translating them into cation influx to adapt and respond to these physical cues. All cells in the organism are mechanosensitive, and these physical cues have proven to have an important role in regulating proliferation, cell fate and differentiation, migration and cellular stress, among other processes. Indeed, the mechanical properties of the extracellular matrix in cancer change drastically due to high cell proliferation and modification of extracellular protein secretion, suggesting an important contribution to tumor cell regulation. In this review, we describe the physiological significance of mechanosensitive ion channels, emphasizing their role in cancer and immunity, and providing compelling proof of the importance of continuing to explore their potential as new therapeutic targets in cancer research.

Reverse engineering morphogenesis through Bayesian optimization of physics-based models

Morphogenetic programs direct the cell signaling and nonlinear mechanical interactions between multiple cell types and tissue layers to define organ shape and size. A key challenge for systems and synthetic biology is determining optimal combinations of intra- and inter-cellular interactions to predict an organ's shape, size, and function. Physics-based mechanistic models that define the subcellular force distribution facilitate this, but it is extremely challenging to calibrate parameters in these models from data. To solve this inverse problem, we created a Bayesian optimization framework to determine the optimal cellular force distribution such that the predicted organ shapes match the desired organ shapes observed within the experimental imaging data. This integrative framework employs Gaussian Process Regression (GPR), a non-parametric kernel-based probabilistic machine learning modeling paradigm, to learn the mapping functions relating to the morphogenetic programs that generate and maintain the final organ shape. We calibrated and tested the method on cross-sections of Drosophila wing imaginal discs, a highly informative model organ system, to study mechanisms that regulate epithelial processes that range from development to cancer. As a specific test case, the parameter estimation framework successfully infers the underlying changes in core parameters needed to match simulation data with time series imaging data of wing discs perturbed with collagenase. Unexpectedly, the framework also identifies multiple distinct parameter sets that generate shapes similar to wild-type organ shapes. This platform enables an efficient, global sensitivity analysis to support the necessity of both actomyosin contractility and basal ECM stiffness to generate and maintain the curved shape of the wing imaginal disc. The optimization framework, combined with fixed tissue imaging, identified that Piezo, a mechanosensitive ion channel, impacts fold formation by regulating the apical-basal balance of actomyosin contractility and elasticity of ECM. This framework is extensible toward reverse-engineering the morphogenesis of any organ system and can be utilized in real-time control of complex multicellular systems.

3D porous sodium alginate-silk fibroin composite bead based in vitro tumor model for screening of anti-cancer drug and induction of magneto-apoptosis

The development of 3D scaffold-based in vitro tumor models can help to address the limitations of cell culture and animal models for designing and screening anticancer drugs. In this study, in vitro 3D tumor models using sodium alginate (SA) and sodium alginate/silk fibroin (SA/SF) porous beads were developed. The beads were non-toxic and A549 cells had a high tendency to adhere, proliferate, and form tumor-like aggregates within SA/SF beads. The 3D tumor model based on these beads had better efficacy for anti-cancer drug screening than the 2D cell culture model. Additionally, the SA/SF porous beads loaded with superparamagnetic iron oxide nanoparticles were used to explore their magneto-apoptosis ability. The cells exposed to a high magnetic field were more likely to undergo apoptosis than those exposed to a low magnetic field. These findings suggest that the SA/SF porous beads and SPIONs loaded SA/SF porous beads-based tumor models could be useful for drug screening, tissue engineering, and mechanobiology studies.

Ultrasound-targeted microbubble destruction remodels tumour microenvironment to improve immunotherapeutic effect

Cancer immunotherapy (CIT) has gained increasing attention and made promising progress in recent years, especially immune checkpoint inhibitors such as antibodies blocking programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4). However, its therapeutic efficacy is only 10-30% in solid tumours and treatment sensitivity needs to be improved. The complex tissue environment in which cancers originate is known as the tumour microenvironment (TME) and the complicated and dynamic TME is correlated with the efficacy of immunotherapy. Ultrasound-targeted microbubble destruction (UTMD) is an emerging technology that integrates diagnosis and therapy, which has garnered much traction due to non-invasive, targeted drug delivery and gene transfection characteristics. UTMD has also been studied to remodel TME and improve the efficacy of CIT. In this review, we analyse the effects of UTMD on various components of TME, including CD8⁺ T cells, tumour-infiltrating myeloid cells, regulatory T cells, natural killer cells and tumour vasculature. Moreover, UTMD enhances the permeability of the blood-brain barrier to facilitate drug delivery, thus improving CIT efficacy in vivo animal experiments. Based on this, we highlight the potential of immunotherapy against various cancer species and the clinical application prospects of UTMD.

Mechanosensitive ion channels in apoptosis and ferroptosis: focusing on the role of Piezo1

Mechanosensitive ion channels sense mechanical stimuli applied directly to the cellular membranes or indirectly through their tethered components, provoking cellular mechanoresponses. Among others, Piezo1 mechanosensitive ion channel is a relatively novel Ca2+-permeable channel that is primarily present in non-sensory tissues. Recent studies have demonstrated that Piezo1 plays an important role in Ca2+-dependent cell death, including apoptosis and ferroptosis, in the presence of mechanical stimuli. It has also been proven that cancer cells are sensitive to mechanical stresses due to higher expression levels of Piezo1 compared to normal cells. In this review, we discuss Piezo1-mediated cell death mechanisms and therapeutic strategies to inhibit or induce cell death by modulating the activity of Piezo1 with pharmacological drugs or mechanical perturbations induced by stretch and ultrasound. [BMB Reports 2023; 56(3): 145-152].

Mechanosensitive ion channels in apoptosis and ferroptosis: focusing on the role of Piezo1

Mechanosensitive ion channels sense mechanical stimuli applied directly to the cellular membranes or indirectly through their tethered components, provoking cellular mechanoresponses. Among others, Piezo1 mechanosensitive ion channel is a relatively novel Ca2+-permeable channel that is primarily present in non-sensory tissues. Recent studies have demonstrated that Piezo1 plays an important role in Ca2+-dependent cell death, including apoptosis and ferroptosis, in the presence of mechanical stimuli. It has also been proven that cancer cells are sensitive to mechanical stresses due to higher expression levels of Piezo1 compared to normal cells. In this review, we discuss Piezo1-mediated cell death mechanisms and therapeutic strategies to inhibit or induce cell death by modulating the activity of Piezo1 with pharmacological drugs or mechanical perturbations induced by stretch and ultrasound. [BMB Reports 2023; 56(3): 145-152].

Developmental function of Piezo1 in mouse submandibular gland morphogenesis

Mechanically activated factors are important in organogenesis, especially in the formation of secretory organs, such as salivary glands. Piezo-type mechanosensitive ion channel component 1 (Piezo1), although previously studied as a physical modulator of the mechanotransduction, was firstly evaluated on its developmental function in this study. The detailed localization and expression pattern of Piezo1 during mouse submandibular gland (SMG) development were analyzed using immunohistochemistry and RT-qPCR, respectively. The specific expression pattern of Piezo1 was examined in acinar-forming epithelial cells at embryonic day 14 (E14) and E16, which are important developmental stages for acinar cell differentiation. To understand the precise function of Piezo1 in SMG development, siRNA against Piezo1 (siPiezo1) was employed as a loss-of-function approach, during in vitro organ cultivation of SMG at E14 for the designated period. Alterations in the histomorphology and expression patterns of related signaling molecules, including Bmp2, Fgf4, Fgf10, Gli1, Gli3, Ptch1, Shh, and Tgfβ-3, were examined in acinar-forming cells after 1 and 2 days of cultivation. Particularly, altered localization patterns of differentiation-related signaling molecules including Aquaporin5, E-cadherin, Vimentin, and cytokeratins would suggest that Piezo1 modulates the early differentiation of acinar cells in SMGs by modulating the Shh signaling pathway.

Mechanosensitive channel MscL induces non-apoptotic cell death and its suppression of tumor growth by ultrasound

Mechanosensitive channel of large conductance (MscL) is the most thoroughly studied mechanosensitive channel in prokaryotes. Owing to its small molecular weight, clear mechanical gating mechanism, and nanopore forming ability upon opening, accumulating studies are implemented in regulating cell function by activating mechanosensitive channel of large conductance in mammalian cells. This study aimed to investigate the potentials of mechanosensitive channel of large conductance as a nanomedicine and a mechano-inducer in non-small cell lung cancer (NSCLC) A549 cells from the view of molecular pathways and acoustics. The stable cytoplasmic vacuolization model about NSCLC A549 cells was established via the targeted expression of modified mechanosensitive channel of large conductance channels in different subcellular organelles. Subsequent morphological changes in cellular component and expression levels of cell death markers are analyzed by confocal imaging and western blots. The permeability of mitochondrial inner membrane (MIM) exhibited a vital role in cytoplasmic vacuolization formation. Furthermore, mechanosensitive channel of large conductance channel can be activated by low intensity focused ultrasound (LIFU) in A549 cells, and the suppression of A549 tumors in vivo was achieved by LIFU with sound pressure as low as 0.053 MPa. These findings provide insights into the mechanisms underlying non-apoptotic cell death, and validate the nanochannel-based non-invasive ultrasonic strategy for cancer therapy.

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.

Magnetic particles for triggering insulin release in INS-1E cells subjected to a rotating magnetic field

Diabetes is a major global health threat. Both academics and industry are striving to develop effective treatments for this disease. In this work, we present a new approach to induce insulin release from β-islet pancreatic cells (INS-1E) by mechanical stimulation. Two types of experiments were carried out. First, a local stimulation was performed by dispersing anisotropic magnetic particles within the cell medium, which settled down almost immediately on cell plasma membranes. Application of a low frequency magnetic field (up to 40 Hz) generated by a custom-made magnetic device resulted in oscillations of these particles, which then exerted a mechanical constraint on the cell plasma membranes. The second type of experiment consisted of a global stimulation, where cells were grown on magneto-elastic membranes composed of a biocompatible polymer with embedded magnetic particles. Upon application of a rotating magnetic field, magnetic particles within the membrane were attracted towards the field source, resulting in the membrane's vibrations being transmitted to the cells grown on it. In both experiments, the cell response to these mechanical stimulations caused by application of the variable magnetic field was quantified via the measurement of insulin release in the growth medium. We demonstrated that the mechanical action induced by the motion of magnetic particles or by membrane vibrations was an efficient stimulus for insulin granule secretion from β-cells. This opens a wide range of possible applications including the design of a system which triggers insulin secretion by β-islet pancreatic cells on demand.

The Roles of FHL3 in Cancer

The four and a half LIM domain protein 3, also named the LIM-protein FHL3, belongs to the LIM-only family. Based on the special structure of LIM-only proteins, FHL3 can perform significant functions in muscle proliferation and cardiovascular diseases by regulating cell growth and signal transduction. In recent years, there has been increasing evidence of a relation between FHLs and tumor biology, since FHL3 is often overexpressed or downregulated in different cancers. On the one hand, FHL3 can function as a tumor suppressor and influence the expression of downstream genes. On the other hand, FHL3 can also play a role as an oncoprotein in some cancers to promote tumor progression via phosphorylation. Thus, FHL3 is proposed to have a dual effect on cancer progression, reflecting its complex roles in cancer. This review focuses on the roles of FHL3 in cancer progression and discusses the interaction of FHL3 with other proteins and transcription factors. Finally, the clinical significance of FHL3 for the treatment of cancers is discussed.