Recurrent activations of transient receptor potential vanilloid-1 and vanilloid-4 promote cellular proliferation and migration in esophageal squamous cell carcinoma cells

Development and dysfunction of structural cells in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a disorder characterized by dysfunction and chronic local inflammation of the esophagus. The incidence and prevalence of EoE are increasing worldwide. The mechanisms responsible are poorly understood, and effective treatment options are limited. From the lumen outward, the esophagus comprises stratified squamous epithelium, lamina propria, and muscle. The tissue-specific nature of EoE strongly suggests that structural cells in the esophagus are involved in the EoE diathesis. Epithelial basal cell hyperplasia and dilated intercellular spaces are cardinal features of EoE. Some patients with EoE develop lamina propria fibrosis, strictures, or esophageal muscle dysmotility. Clinical symptoms of EoE are only weakly correlated with peak eosinophil count, implying that other cell types contribute to EoE pathogenesis. Epithelial, endothelial, muscle, and fibroblast cells can each initiate inflammation and repair, regulate tissue resident immune cells, recruit peripheral leukocytes, and tailor adaptive immune cell responses. A better understanding of how structural cells maintain tissue homeostasis, respond to cell-intrinsic and cell-extrinsic stressors, and exacerbate and/or resolve inflammatory responses in the esophagus is needed. This knowledge will facilitate the development of more efficacious treatment strategies for EoE that can restore homeostasis of both hematopoietic and structural elements in the esophagus.

Widespread transcriptomic alterations of transient receptor potential channel genes in cancer

Ion channels, in particular transient-receptor potential (TRP) channels, are essential genes that play important roles in many physiological processes. Emerging evidence has demonstrated that TRP genes are involved in a number of diseases, including various cancer types. However, we still lack knowledge about the expression alterations landscape of TRP genes across cancer types. In this review, we comprehensively reviewed and summarised the transcriptomes from more than 10 000 samples in 33 cancer types. We found that TRP genes were widespreadly transcriptomic dysregulated in cancer, which was associated with clinical survival of cancer patients. Perturbations of TRP genes were associated with a number of cancer pathways across cancer types. Moreover, we reviewed the functions of TRP family gene alterations in a number of diseases reported in recent studies. Taken together, our study comprehensively reviewed TRP genes with extensive transcriptomic alterations and their functions will directly contribute to cancer therapy and precision medicine.

Capsaicin: A chili pepper bioactive phytocompound with a potential role in suppressing cancer development and progression

Cancer profoundly influences morbidity and fatality rates worldwide. Patients often have dismal prognoses despite recent improvements in cancer therapy regimens. However, potent biomolecules derived from natural sources, including medicinal and dietary plants, contain biological and pharmacological properties to prevent and treat various human malignancies. Capsaicin is a bioactive phytocompound present in red hot chili peppers. Capsaicin has demonstrated many biological effects, including antioxidant, anti-inflammatory, antimicrobial, and anticarcinogenic capabilities. This review highlights the cellular and molecular pathways through which capsaicin exhibits antineoplastic activities. Our work also depicts the synergistic anticancer properties of capsaicin in conjunction with other natural bioactive components and approved anticancer drugs. Capsaicin inhibits proliferation in various cancerous cells, and its antineoplastic actions in numerous in vitro and in vivo carcinoma models impact oncogenesis, tumor-promoting and suppressor genes, and associated signaling pathways. Capsaicin alone or combined with other phytocompounds or approved antineoplastic drugs triggers cell cycle progression arrest, generating reactive oxygen species and disrupting mitochondrial membrane integrity, ultimately stimulating caspases and promoting death. Furthermore, capsaicin alone or in combination can promote apoptosis in carcinoma cells by enhancing the p53 and c-Myc gene expressions. In conclusion, capsaicin alone or in combination can have enormous potential for cancer prevention and intervention, but further high-quality studies are needed to firmly establish the clinical efficacy of this phytocompound.

Capsaicin orchestrates metastasis in gastric cancer via modulating expression of TRPV1 channels and driving gut microbiota disorder

The association between capsaicin, the major natural pungent compound of chili peppers, and gastric cancer progression has engendered conflicting findings. In this work, we sought to explore the character of a high capsaicin diet in gastric cancer metastasis and its possible mechanism. The impact of high capsaicin consumption on gastric cancer metastasis was investigated in vivo (xenograft mouse and zebrafish models) and in vitro (biochemical and molecular assays). It was demonstrated that high diet of capsaicin gave rise to accelerate tumor metastasis, which was partially mediated by elevating the expression of transient receptor potential vanilloid 1 (TRPV1) in gastric cancer cells. Importantly, we found that genetic depletion of TRPV1 could reduce gastric cancer metastasis by diminishing the motility of tumor cells in vitro, but acted poorly in xenograft mouse model. Considering the distribution of capsaicin in vivo, 16S rRNA sequencing and fecal microbiota transplantation (FMT) were used to appraise whether the gut microbiota involved in the high capsaicin diet induced metastasis. It was demonstrated that the level of Firmicutes and Clostridiales was expressively boosted following the high consumption of capsaicin. This microbial shift contributed to the increased peripheral 5-hydroxytryptamine (5-HT) levels, yielding the aggravated metastatic burden. Collectively, our findings highlighted the potential risk of high capsaicin diet in promoting gastric cancer metastasis by virtue of modulating TRPV1 expression and gut microbiota composition, indicating the importance of controlled consumption of chili peppers for patients with gastric cancer. Video Abstract.

TRP Channels in Cancer: Signaling Mechanisms and Translational Approaches

Ion channels play a crucial role in a wide range of biological processes, including cell cycle regulation and cancer progression. In particular, the transient receptor potential (TRP) family of channels has emerged as a promising therapeutic target due to its involvement in several stages of cancer development and dissemination. TRP channels are expressed in a large variety of cells and tissues, and by increasing cation intracellular concentration, they monitor mechanical, thermal, and chemical stimuli under physiological and pathological conditions. Some members of the TRP superfamily, namely vanilloid (TRPV), canonical (TRPC), melastatin (TRPM), and ankyrin (TRPA), have been investigated in different types of cancer, including breast, prostate, lung, and colorectal cancer. TRP channels are involved in processes such as cell proliferation, migration, invasion, angiogenesis, and drug resistance, all related to cancer progression. Some TRP channels have been mechanistically associated with the signaling of cancer pain. Understanding the cellular and molecular mechanisms by which TRP channels influence cancer provides new opportunities for the development of targeted therapeutic strategies. Selective inhibitors of TRP channels are under initial scrutiny in experimental animals as potential anti-cancer agents. In-depth knowledge of these channels and their regulatory mechanisms may lead to new therapeutic strategies for cancer treatment, providing new perspectives for the development of effective targeted therapies.

Transient Receptor Potential Vanilloid 4: a Double-Edged Sword in the Central Nervous System

Transient receptor potential vanilloid 4 (TRPV4) is a nonselective cation channel that can be activated by diverse stimuli, such as heat, mechanical force, hypo-osmolarity, and arachidonic acid metabolites. TRPV4 is widely expressed in the central nervous system (CNS) and participates in many significant physiological processes. However, accumulative evidence has suggested that deficiency, abnormal expression or distribution, and overactivation of TRPV4 are involved in pathological processes of multiple neurological diseases. Here, we review the latest studies concerning the known features of this channel, including its expression, structure, and its physiological and pathological roles in the CNS, proposing an emerging therapeutic strategy for CNS diseases.

Association between chili pepper consumption and risk of gastrointestinal-tract cancers: A meta-analysis

Background

Stimulating food is emerging as an important modifiable factor in the development of gastrointestinal (GI) tract cancers, but the association between chili pepper consumption and the risk of GI cancers is unclear. We aimed to evaluate the direction and magnitude of the association between chili pepper consumption and the risk of GI cancers.

Methods

A literature search was performed in PubMed, Embase, and Web of Science databases from inception to 22 December 2021. Observational studies reporting the association between chili pepper consumption and the risk of gastric cancer (GC), esophageal cancer (EC), and/or colorectal cancer (CRC) in adults were eligible for inclusion. Data extraction and quality assessment were conducted independently by two reviewers for the included literature. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup analyses were also performed based on the cancer type, study design, region of the study, study quality, and adjustments.

Results

A total of 11,421 studies were screened, and 14 case-control studies were included involving 5009 GI cancers among 11,310 participants. The summary OR showed that high consumption of chili pepper was positively related to the risk of GI cancers (OR = 1.64; 95% CI: 1.00–2.70). A stronger positive relationship was observed between chili pepper consumption and EC risk (OR = 2.71; 95% CI: 1.54–4.75), but there was no statistically significant association between GC and CRC risk. In analyses stratified by geographical location, a positive association was found between chili pepper consumption and the risk of GI cancers in Asian studies (OR = 2.50; 95% CI: 1.23–5.08), African studies (OR = 1.62; 95% CI: 1.04–2.52), and North American studies (OR = 2.61; 95% CI: 1.34–5.08), but an inverse association was seen in South American studies (OR = 0.50; 95% CI: 0.29–0.87) and European studies (OR = 0.30; 95% CI: 0.15–0.61).

Conclusion

This meta-analysis suggests that chili pepper is a risk factor for certain GI cancers (e.g., EC). Geographical regions influence the risk of GI cancers, especially in Asian, African, and North American populations, which require more attention during dietary guidance.

Systematic review registration

[https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42022320670].

High spicy food intake may increase the risk of esophageal cancer: A meta-analysis and systematic review

Spicy food is popular with people around the world and reports on the association between spicy food intake and esophageal cancer (EC) risk have been controversial. Therefore, we conducted a meta-analysis of 25 studies to provide the latest evidence for this uncertainty. We hypothesized that high spicy food intake is associated with an increased risk of EC. A database was searched to identify case-control or cohort studies of spicy food intake associated with EC through March 2022. Combined odds ratios (ORs) and their 95% CIs were used to estimate the effect of spicy food intake on EC. Subgroup analyses and sensitivity analyses were also performed. All data were analyzed using STATA 15.1 software. Twenty-five studies from 22 articles met the inclusion criteria for the meta-analysis (7810 patients with EC and 515,397 controls). Despite significant heterogeneity (P < .001), the comparison of highest versus lowest spicy food intake in each study showed a significant OR of 1.70 (95% CI, 1.30-2.22). In subgroup analyses, this positive association was found among the Chinese population, different sample sizes of EC, different sources of the control group, and different quality of articles. However, for India, as well as for other countries, esophageal squamous cell carcinoma and esophageal adenocarcinoma showed no statistically significant association. This meta-analysis suggests that high levels of spicy food intake may be associated with an increased risk of EC, although 1 prospective study found an inverse association. Additional studies are necessary to confirm the relationship between spicy food and EC risk.

Thermal stress involved in TRPV2 promotes tumorigenesis through the pathways of HSP70/27 and PI3K/Akt/mTOR in esophageal squamous cell carcinoma

BACKGROUND

The transient receptor potential vanilloid receptor 2 (TRPV2) has been found to participate in the pathogenesis of various types of cancers, however, its role(s) in the tumorigenesis of ESCC remain poorly understood.

METHODS

Western blotting and immunohistochemistry were performed to determine the expression profiles of TRPV2 in the ESCC patient tissues. A series of in vitro and in vivo experiments were conducted to reveal the role of TRPV2 in the tumorigenesis of ESCC.

RESULTS

Our study first uncovered that the activation of TRPV2 by recurrent acute thermal stress (54 °C) or O1821 (20 μM) promoted cancerous behaviours in ESCC cells. The pro-angiogenic capacity of the ESCC cells was found to be enhanced profoundly and both tumour formation and metastasis that originated from the cells were substantially promoted in nude mouse models upon the activation of TRPV2. These effects were inhibited significantly by tranilast (120 μM) and abolished by TRPV2 knockout. Conversely, overexpression of TRPV2 could switch the cells to tumorigenesis upon activation of TRPV2. Mechanistically, the driving role of TRPV2 in the progression of ESCC is mainly regulated by the HSP70/27 and PI3K/Akt/mTOR signalling pathways.

CONCLUSIONS

We revealed that TRPV2-PI3K/Akt/mTOR is a novel and promising target for the prevention and treatment of ESCC.

Regulation of transient receptor potential channels by traditional Chinese medicines and their active ingredients

In recent years, activation of thermal transient receptor potential (TRP) ion channels at a range of temperatures has received widespread attention as a target for traditional Chinese medicine (TCM) to regulate body temperature and relieve pain. Discovery of transient receptor potential vanilloid 1 (TRPV1) was awarded a Nobel Prize, reflecting the importance of these channels. Here, the regulatory effects of TCMs and their active ingredients on TRP ion channels are reviewed, and future directions for research on the cold, hot, warm, cool, and neutral natures of TCMs are considered. In herbs with cold, hot, warm, cool, and neutral natures, we found 29 TCMs with regulatory effects on TRP ion channels, including Cinnamomi Cortex, Capsici Fructus, Rhei Radix et Rhizoma, Macleayae cordatae Herba, Menthae Haplocalycis Herba, and Rhodiolae Crenulatae Radix et Rhizoma. Although some progress has been made in understanding the regulation of TRP ion channels by TCMs and their ingredients, the molecular mechanism by which TCMs have this effect remains to be further studied. We hope this review will provide a reference for further research on the cold, hot, warm, cool, and neutral natures of TCMs.

Loratadine, an antihistaminic drug, suppresses the proliferation of endometrial stromal cells by inhibition of TRPV2

The transient receptor potential (TRP) channel TRPV2 is widely expressed in a variety of different cell types and tissues. However, elucidating the exact biological functions of TRPV2 is significantly hampered by the lack of selective pharmacological tools to modulate channel activity in vitro and in vivo. This study aimed to identify new compounds that modify TRPV2 activity via the use of a plate-based calcium imaging approach to screen a drug repurposing library. Three antihistaminic drugs, loratadine, astemizole and clemizole were identified to reduce calcium-influx evoked by the TRPV2 agonist tetrahydrocannabivarin in HEK293 cells expressing murine TRPV2. Using single-cell calcium-microfluorimetry and whole-cell patch clamp recordings, we further confirmed that all three compounds induced a concentration-dependent block of TRPV2-mediated Ca²⁺ influx and whole-cell currents, with loratadine being the most potent antagonist of TRPV2. Moreover, this study demonstrated that loratadine was able to block both the human and mouse TRPV2 orthologs, without inhibiting the activity of other closely related members of the TRPV superfamily. Finally, loratadine inhibited TRPV2-dependent responses in a primary culture of mouse endometrial stromal cells and attenuated cell proliferation and migration in in vitro cell proliferation and wound healing assays. Taken together, our study revealed that the antihistaminic drugs loratadine, astemizole and clemizole target TRPV2 in a concentration-dependent manner. The identification of these antihistaminic drugs as blockers of TRPV2 may form a new starting point for the synthesis of more potent and selective TRPV2 antagonists, which could further lead to the unravelling of the physiological role of the channel.

A Review on the Role of TRP Channels and Their Potential as Drug Targets_An Insight Into the TRP Channel Drug Discovery Methodologies

Transient receptor potential (TRP) proteins are a large group of ion channels that control many physiological functions in our body. These channels are considered potential therapeutic drug targets for various diseases such as neurological disorders, cancers, cardiovascular disease, and many more. The Nobel Prize in Physiology/Medicine in the year 2021 was awarded to two scientists for the discovery of TRP and PIEZO ion channels. Improving our knowledge of technologies for their study is essential. In the present study, we reviewed the role of TRP channel types in the control of normal physiological functions as well as disease conditions. Also, we discussed the current and novel technologies that can be used to study these channels successfully. As such, Flux assays for detecting ionic flux through ion channels are among the core and widely used tools for screening drug compounds. Technologies based on these assays are available in fully automated high throughput set-ups and help detect changes in radiolabeled or non-radiolabeled ionic flux. Aurora’s Ion Channel Reader (ICR), which works based on label-free technology of flux assay, offers sensitive, accurate, and reproducible measurements to perform drug ranking matching with patch-clamp (gold standard) data. The non-radiolabeled trace-based flux assay coupled with the ICR detects changes in various ion types, including potassium, calcium, sodium, and chloride channels, by using appropriate tracer ions. This technology is now considered one of the very successful approaches for analyzing ion channel activity in modern drug discovery. It could be a successful approach for studying various ion channels and transporters, including the different members of the TRP family of ion channels.

Physiological and Pathological Significance of Esophageal TRP Channels: Special Focus on TRPV4 in Esophageal Epithelial Cells

Transient receptor potential vanilloid 4 (TRPV4) is a non-selective cation channel that is broadly expressed in different human tissues, including the digestive system, where it acts as a molecular sensor and a transducer that regulates a variety of functional activities. Despite the extensive research to determine the role of this channel in the physiology and pathophysiology of different organs, the unique morphological and functional features of TRPV4 in the esophagus remain largely unknown. Ten years ago, TRPV4 was shown to be highly expressed in esophageal epithelial cells where its activation induces Ca²⁺-dependent ATP release, which, in turn, mediates several functions, ranging from mechanosensation to wound healing. This review summarizes the research progress on TRPV4, and focuses on the functional expression of TRPV4 in esophageal epithelium and its possible role in different esophageal diseases that would support TRPV4 as a candidate target for future therapeutic approaches to treat patients with these conditions.

Functional Transient Receptor Potential Ankyrin 1 and Vanilloid 1 Ion Channels Are Overexpressed in Human Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a common cancer with poor prognosis. Transient Receptor Potential Ankyrin 1 (TRPA1) and Vanilloid 1 (TRPV1) receptors are non-selective cation channels expressed on primary sensory neurons and epithelial and immune cells. TRPV1 mRNA and immunopositivity, as well as TRPA1-like immunoreactivity upregulation, were demonstrated in OSCC, but selectivity problems with the antibodies still raise questions and their functional relevance is unclear. Therefore, here, we investigated TRPA1 and TRPV1 expressions in OSCC and analyzed their functions. TRPA1 and TRPV1 mRNA were determined by RNAscope in situ hybridization and qPCR. Radioactive ₄₅Ca²⁺ uptake and ATP-based luminescence indicating cell viability were measured in PE/CA-PJ41 cells in response to the TRPA1 agonist allyl-isothiocyanate (AITC) and TRPV1 agonist capsaicin to determine receptor function. Both TRPA1 and TRPV1 mRNA are expressed in the squamous epithelium of the human oral mucosa and in PE/CA-PJ41 cells, and their expressions are significantly upregulated in OSCC compared to healthy mucosa. TRPA1 and TRPV1 activation (100 µM AITC, 100 nM capsaicin) induced ₄₅Ca²⁺-influx into PE/CA-PJ41 cells. Both AITC (10 nM-5 µM) and capsaicin (100 nM-45 µM) reduced cell viability, reaching significant decrease at 100 nM AITC and 45 µM capsaicin. We provide the first evidence for the presence of non-neuronal TRPA1 receptor in the OSCC and confirm the expression of TRPV1 channel. These channels are functionally active and might regulate cancer cell viability.

Capsaicin and cancer: Guilty as charged or innocent until proven guilty?

With an estimated 2 billion chili pepper connoisseurs worldwide, the human exposure to capsaicin is enormous. Therefore, the question whether nutritional capsaicin is a cancer causing or cancer preventive agent is of utmost importance. The gamut of human epidemiology studies suggests that capsaicin in modest, "restaurant-like" doses is not only safe to eat, but it may even provide health benefits, such as lower cancer-related death rate. Very "hot" food is, however, probably better avoided. Importantly, no increased cancer risk was reported in patients following topical (skin or intravesical) capsaicin therapy. Aberrant capsaicin receptor TRPV1 expression was noted in various cancers with potential implications for cancer therapy, diagnosis and prognostication. Indeed, capsaicin can kill cancer cells by a combination of on- and off-target mechanisms, though it remains unclear if this can be exploited for therapeutic purposes. The literature on capsaicin and cancer is vast and controversial. This review aims to find answers to questions that are relevant for our daily life and medical practice.

Evaluating methods and protocols of ferritin-based magnetogenetics

FeRIC (Ferritin iron Redistribution to Ion Channels) is a magnetogenetic technique that uses radiofrequency (RF) alternating magnetic fields to activate the transient receptor potential channels, TRPV1 and TRPV4, coupled to cellular ferritins. In cells expressing ferritin-tagged TRPV, RF stimulation increases the cytosolic Ca²⁺ levels via a biochemical pathway. The interaction between RF and ferritin increases the free cytosolic iron levels that, in turn, trigger chemical reactions producing reactive oxygen species and oxidized lipids that activate the ferritin-tagged TRPV. In this pathway, it is expected that experimental factors that disturb the ferritin expression, the ferritin iron load, the TRPV functional expression, or the cellular redox state will impact the efficiency of RF in activating ferritin-tagged TRPV. Here, we examined several experimental factors that either enhance or abolish the RF control of ferritin-tagged TRPV. The findings may help optimize and establish reproducible magnetogenetic protocols.

TRPV Protein Family-From Mechanosensing to Cancer Invasion

Biophysical cues from the cellular microenvironment are detected by mechanosensitive machineries that translate physical signals into biochemical signaling cascades. At the crossroads of extracellular space and cell interior are located several ion channel families, including TRP family proteins, that are triggered by mechanical stimuli and drive intracellular signaling pathways through spatio-temporally controlled Ca2+-influx. Mechanosensitive Ca2+-channels, therefore, act as critical components in the rapid transmission of physical signals into biologically compatible information to impact crucial processes during development, morphogenesis and regeneration. Given the mechanosensitive nature of many of the TRP family channels, they must also respond to the biophysical changes along the development of several pathophysiological conditions and have also been linked to cancer progression. In this review, we will focus on the TRPV, vanilloid family of TRP proteins, and their connection to cancer progression through their mechanosensitive nature.

Expression Profiles of ASIC1/2 and TRPV1/4 in Common Skin Tumors

The acid-sensing ion channels ASIC1 and ASIC2, as well as the transient receptor potential vanilloid channels TRPV1 and TRPV4, are proton-gated cation channels that can be activated by low extracellular pH (pH_e), which is a hallmark of the tumor microenvironment in solid tumors. However, the role of these channels in the development of skin tumors is still unclear. In this study, we investigated the expression profiles of ASIC1, ASIC2, TRPV1 and TRPV4 in malignant melanoma (MM), squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and in nevus cell nevi (NCN). We conducted immunohistochemistry using paraffin-embedded tissue samples from patients and found that most skin tumors express ASIC1/2 and TRPV1/4. Striking results were that BCCs are often negative for ASIC2, while nearly all SCCs express this marker. Epidermal MM sometimes seem to lack ASIC1 in contrast to NCN. Dermal portions of MM show strong expression of TRPV1 more frequently than dermal NCN portions. Some NCN show a decreasing ASIC1/2 expression in deeper dermal tumor tissue, while MM seem to not lose ASIC1/2 in deeper dermal portions. ASIC1, ASIC2, TRPV1 and TRPV4 in skin tumors might be involved in tumor progression, thus being potential diagnostic and therapeutic targets.

The Impact of TRPV1 on Cancer Pathogenesis and Therapy: A Systematic Review

The transient receptor potential cation channel subfamily V member 1 (TRPV1) is a transmembrane protein that can be activated by various physical and chemical stimuli and is associated with pain transduction. In recent years, TRPV1 was discovered to play essential roles in cancer tumorigenesis and development, as TRPV1 expression levels are altered in numerous cancer cell types. Several investigations have discovered direct associations between TRPV1 and cancer cell proliferation, cell death, and metastasis. Furthermore, about two dozen TRPV1 agonists/antagonists are under clinical trial, as TRPV1 is a potential drug target for treating various diseases. Hence, more researchers are focusing on the effects of TRPV1 agonists or antagonists on cancer tumorigenesis and development. However, both agonists and antagonists may reveal anti-cancer effects, and the effect may function via or be independent of TRPV1. In this review, we provide an overview of the impact of TRPV1 on cancer cell proliferation, cell death, and metastasis, as well as on cancer therapy and the tumor microenvironment, and consider the implications of using TRPV1 agonists and antagonists for future research and potential therapeutic approaches.

SGK1 mediates hypotonic challenge-induced proliferation in basilar artery smooth muscle cells via promoting CREB signaling pathway

Hypotonic stimulus enlarges cell volume and increased cell proliferation with the exact mechanisms unknown. Glucocorticoid-induced kinase-1 (SGK1) is a serine/threonine kinase that can be regulated by osmotic pressure. We have revealed that SGK1 was activated by hypotonic solution-induced lowering of intracellular Cl- concentration. Therefore, we further examined whether SGK1 mediated hypotonic solution-induced proliferation and the internal mechanisms in basilar smooth muscle cells (BASMCs). In the present study, BrdU incorporation assay, flow cytometry, western blotting were performed to evaluate cell viability, cell cycle transition, and the expression of cell cycle regulators and other related proteins. We found that silence of SGK1 largely blunted hypotonic challenge-induced increase in cell viability and cell cycle transition from G0/G1 phase to S phase, whereas overexpression of SGK1 showed the opposite effects. The effect of SGK1 on proliferation was related to the upregulation of cyclin D1 and cyclin E1, and the downregulation of p27 and p21, which is mediated by the interaction between SGK1 and cAMP responsive element-binding protein (CREB). Moreover, we overexpressed ClC-3 Cl- channel to further verify the role of SGK1 in low Cl- environment-induced proliferation. The results revealed that overexpression of ClC-3 further enhanced hypotonic solution-induced cell viability, cell cycle transition, and CREB activation, which were alleviated or potentiated by silencing or overexpression of SGK1. In summary, this study provides compelling evidences that SGK1, as a Cl--sensitive kinase, is a critical link between low osmotic pressure and proliferation in BASMCs, and shed a new light on the treatment of proliferation-associated cardiovascular diseases.

Differences of the tumour cell glycocalyx affect binding of capsaicin-loaded chitosan nanocapsules

The glycocalyx regulates the interaction of mammalian cells with extracellular molecules, such as cytokines. However, it is unknown to which extend the glycocalyx of distinct cancer cells control the binding and uptake of nanoparticles. In the present study, exome sequencing data of cancer patients and analysis of distinct melanoma and bladder cancer cell lines suggested differences in cancer cell-exposed glycocalyx components such as heparan sulphate. Our data indicate that glycocalyx differences affected the binding of cationic chitosan nanocapsules (Chi-NCs). The pronounced glycocalyx of bladder cancer cells enhanced the internalisation of nanoencapsulated capsaicin. Consequently, capsaicin induced apoptosis in the cancer cells, but not in the less glycosylated benign urothelial cells. Moreover, we measured counterion condensation on highly negatively charged heparan sulphate chains. Counterion condensation triggered a cooperative binding of Chi-NCs, characterised by a weak binding rate at low Chi-NC doses and a strongly increased binding rate at high Chi-NC concentrations. Our results indicate that the glycocalyx of tumour cells controls the binding and biological activity of nanoparticles. This has to be considered for the design of tumour cell directed nanocarriers to improve the delivery of cytotoxic drugs. Differential nanoparticle binding may also be useful to discriminate tumour cells from healthy cells.

The Effects of Capsaicin on Gastrointestinal Cancers

Gastrointestinal (GI) cancers are a group of diseases with very high positions in the ranking of cancer incidence and mortality. While they show common features regarding the molecular mechanisms involved in cancer development, organ-specific pathophysiological processes may trigger distinct signaling pathways and intricate interactions with inflammatory cells from the tumoral milieu and mediators involved in tumorigenesis. The treatment of GI cancers is a topic of increasing interest due to the severity of these diseases, their impact on the patients' survivability and quality of life, and the burden they set on the healthcare system. As the efficiency of existing drugs is hindered by chemoresistance and adverse reactions when administered in high doses, new therapies are sought, and emerging drugs, formulations, and substance synergies are the focus of a growing number of studies. A class of chemicals with great potential through anti-inflammatory, anti-oxidant, and anti-tumoral effects is phytochemicals, and capsaicin in particular is the subject of intensive research looking to validate its position in complementing cancer treatment. Our paper thoroughly reviews the available scientific evidence concerning the effects of capsaicin on major GI cancers and its interactions with the molecular pathways involved in the course of these diseases.

TRPV2: A Cancer Biomarker and Potential Therapeutic Target

The Transient Receptor Potential Vanilloid type-2 (TRPV2) channel exhibits oncogenicity in different types of cancers. TRPV2 is implicated in signaling pathways that mediate cell survival, proliferation, and metastasis. In leukemia and bladder cancer, the oncogenic activity of TRPV2 was linked to alteration of its expression profile. In multiple myeloma patients, TRPV2 overexpression correlated with bone tissue damage and poor prognosis. In prostate cancer, TRPV2 overexpression was associated with the castration-resistant phenotype and metastasis. Loss or inactivation of TRPV2 promoted glioblastoma cell proliferation and increased resistance to CD95-induced apoptotic cell death. TRPV2 overexpression was associated with high relapse-free survival in triple-negative breast cancer, whereas the opposite was found in patients with esophageal squamous cell carcinoma or gastric cancer. Another link was found between TRPV2 expression and either drug-induced cytotoxicity or stemness of liver cancer. Overall, these findings validate TRPV2 as a prime candidate for cancer biomarker and future therapeutic target.

OEsophageal Ion Transport Mechanisms and Significance Under Pathological Conditions

Ion transporters play an important role in several physiological functions, such as cell volume regulation, pH homeostasis and secretion. In the oesophagus, ion transport proteins are part of the epithelial resistance, a mechanism which protects the oesophagus against reflux-induced damage. A change in the function or expression of ion transporters has significance in the development or neoplastic progression of Barrett’s oesophagus (BO). In this review, we discuss the physiological and pathophysiological roles of ion transporters in the oesophagus, highlighting transport proteins which serve as therapeutic targets or prognostic markers in eosinophilic oesophagitis, BO and esophageal cancer. We believe that this review highlights important relationships which might contribute to a better understanding of the pathomechanisms of esophageal diseases.

Calcium Entry through TRPV1: A Potential Target for the Regulation of Proliferation and Apoptosis in Cancerous and Healthy Cells

Intracellular calcium (Ca2+) concentration ([Ca2+]i) is a key determinant of cell fate and is implicated in carcinogenesis. Membrane ion channels are structures through which ions enter or exit the cell, depending on the driving forces. The opening of transient receptor potential vanilloid 1 (TRPV1) ligand-gated ion channels facilitates transmembrane Ca2+ and Na+ entry, which modifies the delicate balance between apoptotic and proliferative signaling pathways. Proliferation is upregulated through two mechanisms: (1) ATP binding to the G-protein-coupled receptor P2Y2, commencing a kinase signaling cascade that activates the serine-threonine kinase Akt, and (2) the transactivation of the epidermal growth factor receptor (EGFR), leading to a series of protein signals that activate the extracellular signal-regulated kinases (ERK) 1/2. The TRPV1-apoptosis pathway involves Ca2+ influx and efflux between the cytosol, mitochondria, and endoplasmic reticulum (ER), the release of apoptosis-inducing factor (AIF) and cytochrome c from the mitochondria, caspase activation, and DNA fragmentation and condensation. While proliferative mechanisms are typically upregulated in cancerous tissues, shifting the balance to favor apoptosis could support anti-cancer therapies. TRPV1, through [Ca2+]i signaling, influences cancer cell fate; therefore, the modulation of the TRPV1-enforced proliferation-apoptosis balance is a promising avenue in developing anti-cancer therapies and overcoming cancer drug resistance. As such, this review characterizes and evaluates the role of TRPV1 in cell death and survival, in the interest of identifying mechanistic targets for drug discovery.

TRP Channels in Digestive Tract Cancers

Cancers of the digestive tract are among the most prevalent types of cancer. These types of cancers are often diagnosed at a late stage, which results in a poor prognosis. Currently, many biomedical studies focus on the role of ion channels, in particular transient receptor potential (TRP) channels, in cancer pathophysiology. TRP channels show mostly non-selective permeability to monovalent and divalent cations. TRP channels are often dysregulated in digestive tract cancers, which can result in alterations of cancer hallmark functions, such as enhanced proliferation, migration, invasion and the inability to induce apoptosis. Therefore, TRP channels could serve as potential diagnostic biomarkers. Moreover, TRP channels are mostly expressed on the cell surface and ion channel targeting drugs do not need to enter the cell, making them attractive candidate drug targets. In this review, we summarize the current knowledge about TRP channels in connection to digestive tract cancers (oral cancer, esophageal cancer, liver cancer, pancreatic cancer, gastric cancer and colorectal cancer) and give an outlook on the potential of TRP channels as cancer biomarkers or therapeutic targets.

The TRPV2 cation channels: from urothelial cancer invasiveness to glioblastoma multiforme interactome signature

Changes in transient receptor potential (TRP) Ca²⁺ permeable channels are associated with development and progression of different types of cancer. Herein, we report data relative to the expression and function of TRP vanilloid 2 (TRPV2) channels in cancer. Overexpression of TRPV2 is observed in high-grade urothelial cancers and treatment with the TRPV2 agonist cannabidiol induces apoptosis. In prostate cancer, TRPV2 promotes migration and invasion, and TRPV2 overexpression characterizes the castration-resistant phenotype. In breast cancer cells, inhibition of TRPV2 by tranilast reduces the insulin-like growth factor-1 stimulated proliferation. TRPV2 overexpression in triple-negative breast cancer cells is associated with high recurrence-free survival. Increased TRPV2 overexpression is present in patients with esophageal squamous cell carcinoma associated with advanced disease, lymph node metastasis, and poor prognosis. Increased TRPV2 transcripts have been found both in benign hepatoma and in hepatocarcinomas, where TRPV2 expression is associated with portal vein invasion and reduction of cancer stem cell expression. TRPV2 expression and function has been also evaluated in gliomagenesis. This receptor negatively controls survival, proliferation, and resistance to CD95- or BCNU-induced apoptosis. In glioblastoma stem cells, TRPV2 activation promotes differentiation and inhibits the proliferation in vitro and in vivo. In glioblastoma, the TRPV2 is part of an interactome-based signature complex, which is negatively associated with survival, and it is expressed in high risk of recurrence and temozolomide-resistant patients. Finally, also in hematological malignancies, such as myeloma or acute myeloid leukemia, TRPV2 might represent a target for novel therapeutic approaches. Overall, these findings demonstrate that TRPV2 exhibits an oncogenic activity in different types of cancers, controlling survival, proliferation, migration, angiogenesis, and invasion signaling pathways. Thus, it prompts the pharmacological use of TRPV2 targeting in the control of cancer progression.

Plasma membrane Ca2+-permeable channels and sodium/calcium exchangers in tumorigenesis and tumor development of the upper gastrointestinal tract

The upper gastrointestinal (GI) tumors are multifactorial diseases associated with a combination of oncogenes and environmental factors. Currently, surgery, chemotherapy, radiotherapy and immunotherapy are relatively effective treatment options for the patients with these tumors. However, the asymptomatic phenotype of these tumors during the early stages poses as a significant limiting factor to diagnosis and often renders treatments ineffective. Therefore, new early diagnosis and effective therapy for upper GI tumors are urgently needed. Ca²⁺ is a pivotal intracellular second messenger and plays a crucial role in living cells by regulating several processes from cell division to death. The aberrant Ca²⁺ homeostasis is related to many human pathological conditions and diseases, including cancer, and thus the changes in the expression and function of plasma membrane Ca²⁺ permeable channels and sodium/calcium exchangers are frequently described in tumorigenesis and tumor development of the upper GI tract, including voltage-gated Ca²⁺ channels (VGCC), transient receptor potential (TRP) channels, store-operated channels (SOC) and Na⁺/Ca²⁺ exchanger (NCX). This review will summarize the current knowledge about plasma membrane Ca²⁺ permeable channels and sodium/calcium exchangers in the upper GI tumors and provide a synopsis of recent advancements on the role and involvement of these channels in upper GI tumors as well as a discussion of the possible strategies to target these channels and exchangers for diagnosis and therapy of the upper GI tumors.

Transient receptor potential ion-channel subfamily V member 4: a potential target for cancer treatment

The transient receptor potential ion-channel superfamily consists of nonselective cation channels located mostly on the plasma membranes of numerous animal cell types, which are closely related to sensory information transmission (e.g., vision, pain, and temperature perception), as well as regulation of intracellular Ca2+ balance and physiological activities of growth and development. Transient receptor potential ion channel subfamily V (TRPV) is one of the largest and most diverse subfamilies, including TRPV1-TRPV6 involved in the regulation of a variety of cellular functions. TRPV4 can be activated by various physical and chemical stimuli, such as heat, mechanical force, and phorbol ester derivatives participating in the maintenance of normal cellular functions. In recent years, the roles of TRPV4 in cell proliferation, differentiation, apoptosis, and migration have been extensively studied. Its abnormal expression has also been closely related to the onset and progression of multiple tumors, so TRPV4 may be a target for cancer diagnosis and treatment. In this review, we focused on the latest studies concerning the role of TRPV4 in tumorigenesis and the therapeutic potential. As evidenced by the effects on cancerogenesis, TRPV4 is a potential target for anticancer therapy.