The role of TRPV1 ion channels in the suppression of gastric cancer development

TRP channels in cancer: Therapeutic opportunities and research strategies

The influence of gut microbiota on transient receptor potential (TRP) channels has been identified as an important element in the development of gastrointestinal conditions, yet its involvement in cancer progression is not as thoroughly understood. This review explores the multifaceted roles of TRP channels in oncogenesis and emphasizes their significance in cancer progression and therapeutic outcomes. Critical focus was placed on the influence of traditional medicines, such as traditional Chinese medicine (TCM) related aromatic medicines, on TRP channel functions. Moreover, we explored the interplay between the gut microbiota and TRP channels in cancer signaling, highlighting the therapeutic potential of targeting this axis in cancer treatment. The impact of current therapies on TRP channel function was examined, demonstrating the need for a comprehensive understanding of how different modalities affect TRP channels in cancer. Technological advancements, including artificial intelligence (AI) tools and computer-aided drug development (CADD), have been discussed in the context of leveraging TRP channels for innovative cancer therapies. Future directions emphasize the potential applications of TRP channel research in advancing cancer treatment and enhancing patients' well-being.

Unraveling TRPV1's Role in Cancer: Expression, Modulation, and Therapeutic Opportunities with Capsaicin

Cancer is a global health challenge with rising incidence and mortality rates, posing significant concerns. The World Health Organization reports cancer as a leading cause of death worldwide, contributing to nearly one in six deaths. Cancer pathogenesis involves disruptions in cellular signaling pathways, resulting in uncontrolled cell growth and metastasis. Among emerging players in cancer biology, Transient Receptor Potential (TRP) channels, notably TRPV1, have garnered attention due to their altered expression in cancer cells and roles in tumorigenesis and progression. TRPV1, also known as the capsaicin receptor, is pivotal in cancer cell death and pain mediation, offering promise as a therapeutic target. Activation of TRPV1 triggers calcium influx and affects cell signaling linked to growth and death. Additionally, TRPV1 is implicated in cancer-induced pain and chemo-sensitivity, with upregulation observed in sensory neurons innervating oral cancers. Also, when capsaicin, a compound from chili peppers, interacts with TRPV1, it elicits a "hot" sensation and influences cancer processes through calcium influx. Understanding TRPV1's multifaceted roles in cancer may lead to novel therapeutic strategies for managing cancer-related symptoms and improving patient outcomes. The current review elucidates the comprehensive role of capsaicin in cancer therapy, particularly through the TRPV1 channel, highlighting its effects in various cells via different signaling pathways and discussing its limitations.

SUMOylation-induced membrane localization of TRPV1 suppresses proliferation and migration in gastric cancer cells

Gastric cancer (GC) remains a significant health challenge due to its high mortality rate and the limited efficacy of current targeted therapies. A critical barrier in developing more effective treatments is the lack of understanding of specific mechanisms driving GC progression. This study investigates the role of Transient Receptor Potential Vanilloid 1 (TRPV1), a non-selective cation channel known for its high Ca2+ permeability and tumor-suppressive properties in gastrointestinal cancers. Specifically, we explore the impact of SUMOylation-a dynamic and reversible post-translational modification-on TRPV1's function in GC. We demonstrate that SUMOylation of TRPV1 inhibits cell proliferation and migration in MGC-803 and AGS GC cells. By mutating amino acids near TRPV1's existing SUMO motif (slKpE), we created a bidirectional SUMO motif (EψKψE) that enhances TRPV1 SUMOylation, resulting in further suppression of GC cell proliferation and migration. In vivo studies support these findings, showing that TRPV1 SUMOylation prevents spontaneous tumorigenesis in a mouse GC model. Further investigation reveals that TRPV1 SUMOylation increases the protein's membrane expression by inhibiting its interaction with the adaptor-related protein complex 2 mu 1 subunit (AP2M1). This elevated membrane expression leads to increased intracellular Ca2+ influx, activating the AMP-activated protein kinase (AMPK) pathway, which in turn inhibits the proliferation and migration of GC cells.

Thirdhand smoke exposure promotes gastric tumor development in mouse and human

The pollution of indoor environments and the consequent health risks associated with thirdhand smoke (THS) are increasingly recognized in recent years. However, the carcinogenic potential of THS and its underlying mechanisms have yet to be thoroughly explored. In this study, we examined the effects of short-term THS exposure on the development of gastric cancer (GC) in vitro and in vivo. In a mouse model of spontaneous GC, CC036, we observed a significant increase in gastric tumor incidence and a decrease in tumor-free survival upon THS exposure as compared to control. RNA sequencing of primary gastric epithelial cells derived from CC036 mice showed that THS exposure increased expression of genes related to the extracellular matrix and cytoskeletal protein structure. We then identified a THS exposure-induced 91-gene expression signature in CC036 and a homologous 84-gene signature in human GC patients that predicted the prognosis, with secreted phosphoprotein 1 (SPP1) and tribbles pseudokinase 3 (TRIB3) emerging as potential targets through which THS may promote gastric carcinogenesis. We also treated human GC cell lines in vitro with media containing various concentrations of THS, which, in some exposure dose range, significantly increased their proliferation, invasion, and migration. We showed that THS exposure could activate the epithelial-mesenchymal transition (EMT) pathway at the transcript and protein level. We conclude that short-term exposure to THS is associated with an increased risk of GC and that activation of the EMT program could be one potential mechanism. Increased understanding of the cancer risk associated with THS exposure will help identify new preventive and therapeutic strategies for tobacco-related disease as well as provide scientific evidence and rationale for policy decisions related to THS pollution control to protect vulnerable subpopulations such as children.

Gastric Carcinogenesis and Potential Role of the Transient Receptor Potential Vanilloid 1 (TRPV1) Receptor: An Observational Histopathological Study

The potential role of the transient receptor potential Vanilloid 1 (TRPV1) non-selective cation channel in gastric carcinogenesis remains unclear. The main objective of this study was to evaluate TRPV1 expression in gastric cancer (GC) and precursor lesions compared with controls. Patient inclusion was based on a retrospective review of pathology records. Patients were subdivided into five groups: Helicobacter pylori (H. pylori)-associated gastritis with gastric intestinal metaplasia (GIM) (n = 12), chronic atrophic gastritis (CAG) with GIM (n = 13), H. pylori-associated gastritis without GIM (n = 19), GC (n = 6) and controls (n = 5). TRPV1 expression was determined with immunohistochemistry and was significantly higher in patients with H. pylori-associated gastritis compared with controls (p = 0.002). TRPV1 expression was even higher in the presence of GIM compared with patients without GIM and controls (p < 0.001). There was a complete loss of TRPV1 expression in patients with GC. TRPV1 expression seems to contribute to gastric-mucosal inflammation and precursors of GC, which significantly increases in cancer precursor lesions but is completely lost in GC. These findings suggest TRPV1 expression to be a potential marker for precancerous conditions and a target for individualized treatment. Longitudinal studies are necessary to further address the role of TRPV1 in gastric carcinogenesis.

The role of lidocaine in cancer progression and patient survival

Since its development in 1943, lidocaine has been one of the most commonly used local anesthesia agents for surgical procedures. Lidocaine alters neuronal signal transmission by prolonging the inactivation of fast voltage-gated sodium channels in the cell membrane of neurons, which are responsible for action potential propagation. Recently, it has attracted attention due to emerging evidence suggesting its potential antitumor properties, particularly in the in vitro setting. Further, local administration of lidocaine around the tumor immediately prior to surgical removal has been shown to improve overall survival in breast cancer patients. However, the exact mechanisms driving these antitumor effects remain largely unclear. In this article, we will review the existing literature on the mechanism of lidocaine as a local anesthetic, its effects on the cancer cells and the tumor microenvironment, involved pathways, and cancer progression. Additionally, we will explore recent reports highlighting its impact on clinical outcomes in cancer patients. Taken together, there remains significant ambiguity surrounding lidocaine's functions and roles in cancer biology, particularly in perioperative setting.

Calcitonin gene‑related peptide alleviates hyperoxia‑induced human alveolar cell injury via the CGRPR/TRPV1/Ca2+ axis

Although exogenous calcitonin gene‑related peptide (CGRP) protects against hyperoxia‑induced lung injury (HILI), the underlying mechanisms remain unclear. The present study attempted to elucidate the molecular mechanism by which CGRP protects against hyperoxia‑induced alveolar cell injury. Human alveolar A549 cells were treated with 95% hyperoxia to establish a hyperoxic cell injury model. ELISA was performed to detect the CGRP secretion. Immunofluorescence, quantitative (q)PCR, and western blotting were used to detect the expression and localization of CGRP receptor (CGRPR) and transient receptor potential vanilloid 1 (TRPV1). Cell counting kit‑8 and flow cytometry were used to examine the proliferation and apoptosis of treated cells. Digital calcium imaging and patch clamp were used to analyze the changes in intracellular Ca2+ signaling and membrane currents induced by CGRP in A549 cells. The mRNA and protein expression levels of Cyclin D1, proliferating cell nuclear antigen (PCNA), Bcl‑2 and Bax were detected by qPCR and western blotting. The expression levels of CGRPR and TRPV1 in A549 cells were significantly downregulated by hyperoxic treatment, but there was no significant difference in CGRP release between cells cultured under normal air and hyperoxic conditions. CGRP promoted cell proliferation and inhibited apoptosis in hyperoxia, but selective inhibitors of CGRPR and TRPV1 channels could effectively attenuate these effects; TRPV1 knockdown also attenuated this effect. CGRP induced Ca2+ entry via the TRPV1 channels and enhanced the membrane non‑selective currents through TRPV1 channels. The CGRP‑induced increase in intracellular Ca2+ was reduced by inhibiting the phospholipase C (PLC)/protein kinase C (PKC) pathway. Moreover, PLC and PKC inhibitors attenuated the effects of CGRP in promoting cell proliferation and inhibiting apoptosis. In conclusion, exogenous CGRP acted by inversely regulating the function of TRPV1 channels in alveolar cells. Importantly, CGRP protected alveolar cells from hyperoxia‑induced injury via the CGRPR/TRPV1/Ca2+ axis, which may be a potential target for the prevention and treatment of the HILI.

Transient receptor potential vanilloid-1 (TRPV1) channels act as suppressors of the growth of glioma

The aim of this study was to investigate the expression and function of the transient receptor potential vanilloid 1 (TRPV1) in glioma. We found that the expression of TRPV1 mRNA and protein were upregulated in glioma compared with normal brain by qPCR and western blot analysis. In order to investigate the function of TRPV1 in glioma, short hairpin RNA (shRNA) and the inhibitor of TRPV1 were used. In vitro, the activation of TRPV1 induced cell apoptosis with decreased migration capability and inhibited proliferation, which was abolished upon TRPV1 pharmacological inhibition and silencing. Mechanistically, TRPV1 modulated glioma proliferation through the protein kinase B (Akt) signaling pathway. More importantly, in immunodeficient (NOD-SCID) mouse xenograft models, tumor size was significantly increased when TRPV1 expression was disrupted by a shRNA knockdown approach in vivo. Altogether, our findings indicate that TRPV1 negatively controls glioma cell proliferation in an Akt-dependent manner, which suggests that targeting TRPV1 may be a potential therapeutic strategy for glioma.

Development and therapeutic implications of small molecular inhibitors that target calcium-related channels in tumor treatment

Calcium ion dysregulation exerts profound effects on various physiological activities such as tumor proliferation, migration, and drug resistance. Calcium-related channels play a regulatory role in maintaining calcium ion homeostasis, with most channels being highly expressed in tumor cells. Additionally, these channels serve as potential drug targets for the development of antitumor medications. In this review, we first discuss the current research status of these pathways, examining how they modulate various tumor functions such as epithelial-mesenchymal transition (EMT), metabolism, and drug resistance. Simultaneously, we summarize the recent progress in the study of novel small-molecule drugs over the past 5 years and their current status.

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.

Function and mechanism of action of the TRPV1 channel in the development of triple-negative breast cancer

Transient receptor potential channel subfamily vanilloid 1 (TRPV1) is a member of the transient receptor potential family of nonselective cationic transmembrane channel proteins that are involved in the regulation of calcium homeostasis. It is expressed in various tumor types and has been implicated in the regulation of cancer growth, metastasis, apoptosis, and cancer-related pain. TRPV1 is highly expressed in triple-negative breast cancer (TNBC), and both its agonists and antagonists may exert anti-cancer effects. In this review, we provide an overview of the effect of TRPV1 on TNBC development and its influence on immunotherapy in an attempt to facilitate the development of future treatment strategies.

Mechanism of metal ion-induced cell death in gastrointestinal cancer

Gastrointestinal (GI) cancer is one of the most severe types of cancer, with a significant impact on human health worldwide. Due to the urgent demand for more effective therapeutic strategies against GI cancers, novel research on metal ions for treating GI cancers has attracted increasing attention. Currently, with accumulating research on the relationship between metal ions and cancer therapy, several metal ions have been discovered to induce cell death. In particular, the three novel modes of cell death, including ferroptosis, cuproptosis, and calcicoptosis, have become focal points of research in the field of cancer. Meanwhile, other metal ions have also been found to trigger cell death through various mechanisms. Accordingly, this review focuses on the mechanisms of metal ion-induced cell death in GI cancers, hoping to provide theoretical support for further GI cancer therapies.

The role of metal ions in the occurrence, progression, drug resistance, and biological characteristics of gastric cancer

Metal ions exert pivotal functions within the human body, encompassing essential roles in upholding cell structure, gene expression regulation, and catalytic enzyme activity. Additionally, they significantly influence various pathways implicated in divergent mechanisms of cell death. Among the prevailing malignant tumors of the digestive tract worldwide, gastric cancer stands prominent, exhibiting persistent high mortality rates. A compelling body of evidence reveals conspicuous ion irregularities in tumor tissues, encompassing gastric cancer. Notably, metal ions have been observed to elicit distinct contributions to the progression, drug resistance, and biological attributes of gastric cancer. This review consolidates pertinent literature on the involvement of metal ions in the etiology and advancement of gastric cancer. Particular attention is directed towards metal ions, namely, Na, K, Mg, Ca, Fe, Cu, Zn, and Mn, elucidating their roles in the initiation and progression of gastric cancer, cellular demise processes, drug resistance phenomena, and therapeutic approaches.

A journey from molecule to physiology and in silico tools for drug discovery targeting the transient receptor potential vanilloid type 1 (TRPV1) channel

The heat and capsaicin receptor TRPV1 channel is widely expressed in nerve terminals of dorsal root ganglia (DRGs) and trigeminal ganglia innervating the body and face, respectively, as well as in other tissues and organs including central nervous system. The TRPV1 channel is a versatile receptor that detects harmful heat, pain, and various internal and external ligands. Hence, it operates as a polymodal sensory channel. Many pathological conditions including neuroinflammation, cancer, psychiatric disorders, and pathological pain, are linked to the abnormal functioning of the TRPV1 in peripheral tissues. Intense biomedical research is underway to discover compounds that can modulate the channel and provide pain relief. The molecular mechanisms underlying temperature sensing remain largely unknown, although they are closely linked to pain transduction. Prolonged exposure to capsaicin generates analgesia, hence numerous capsaicin analogs have been developed to discover efficient analgesics for pain relief. The emergence of in silico tools offered significant techniques for molecular modeling and machine learning algorithms to indentify druggable sites in the channel and for repositioning of current drugs aimed at TRPV1. Here we recapitulate the physiological and pathophysiological functions of the TRPV1 channel, including structural models obtained through cryo-EM, pharmacological compounds tested on TRPV1, and the in silico tools for drug discovery and repositioning.

A Stable Cell Line Co-expressing hTRPV1 and GCaMP6s: A Novel Cell-based Assay For High-throughput Screening of hTRPV1 Agonists

BACKGROUND

Transient receptor potential vanilloid-1 (TRPV1) is a non-selective cation channel capable of integrating various noxious chemical and physical stimuli. Recently, human TRPV1 (hTRPV1) has attracted wide attention from researchers because it is closely related to pain, inflammation, temperature perception, and tumors. Our study was aimed at generating a stable cell line co-expressing hTRPV1 receptor and GCaMP6s calcium indicator protein and, based on this, developing high-throughput screening methods for targeting hTRPV1 agonists.

METHODS

The CHO-hTRPV1-GCaMP6s cell line stably expressing hTRPV1 and GCaMP6s was generated by co-transfection of hTRPV1 and GCaMP6s into Chinese hamster ovary (CHO) cells. The high-throughput screening methods were developed based on detecting the concentration of intracellular calcium ions ([Ca2+]i) by using chemically synthesized dyes and genetically encoded calcium indicator (GECI). Meanwhile, the sensitivity and adaptability of these methods in the evaluation of capsaicinoids were also compared.

RESULTS

A stable cell line co-expressing hTRPV1 and GCaMP6s was generated and used to establish a functional high-throughput screening assay based on the measurement of [Ca2+]i by fluorometric imaging plate reader (FLIPR). The GECI exhibited a higher sensitivity and applicability than that of chemically synthesized dyes in detecting the changes in [Ca2+]i induced by capsaicin. The CHO-hTRPV1-GCaMP6s cell line was further used to detect the dose-dependent relationships of various hTRPV1 agonists (comparison of EC50 values: capsaicin (39 ± 1.67 nM) < nonivamide (67 ± 3.05 nM) < piperine (9222 ± 1851 nM)), and this order is consistent with the pharmacological properties of hTRPV1 activation by these agonists.

CONCLUSION

The successful establishment of the CHO-hTRPV1-GCaMP6s cell lines and their application in high-throughput screening of hTRPV1 agonists.

Susceptibility of immature spiral ganglion neurons to aminoglycoside-induced ototoxicity is mediated by the TRPV1 channel in mice

Aminoglycoside antibiotics are among the most common agents that can cause sensorineural hearing loss. From clinical experience, premature babies, whose inner ear is still developing, are more susceptible to aminoglycoside-induced ototoxicity, which is echoed by our previous study carried out in organotypic cultures. This study aimed to investigate whether a nonselective cation channel, TRPV1, contributes to the susceptibility of immature spiral ganglion neurons (SGNs) to the damage caused by aminoglycosides. Through western blotting and immunofluorescence, we found that the TRPV1 expression levels were much higher in immature SGNs than in their mature counterparts. In postnatal day 7 cochlear organotypic cultures, AMG-517 reduced reactive oxygen species generation and inhibited SGN apoptosis under aminoglycoside challenge. However, in adult mice, AMG-517 did not ameliorate the ABR threshold increase at high frequencies (16 kHz and 32 kHz) after aminoglycoside administration, and the SGNs within the cochleae had no morphological changes. By further regulating the function of TRPV1 in primary cultured SGNs with its inhibitor AMG-517 and agonist capsaicin, we demonstrated that TRPV1 is a major channel for aminoglycoside uptake: AMG-517 can significantly reduce, while capsaicin can significantly increase, the uptake of GTTR. In addition, TRPV1 knockdown in SGNs can also significantly reduce the uptake of GTTR. Taken together, our results demonstrated that aminoglycosides can directly enter immature SGNs through the TRPV1 channel. High expression of TRPV1 contributes to the susceptibility of immature SGNs to aminoglycoside-induced damage. The TRPV1 inhibitor AMG-517 has the potential to be a therapeutic agent for preventing aminoglycoside-induced ototoxicity in immature SGNs.

Comprehensive insights into the multifaceted roles of the transient receptor potential vanilloid 1 channel in the digestive system

The transient receptor potential vanilloid (TRPV) channel, a family of calcium transporters comprising six distinct members (TRPV1-6), takes on a paramount role in maintaining intracellular Ca2+ homeostasis in mammalian cells. Notably, TRPV1, among its counterparts, has emerged as the subject of extensive scrutiny, owing to its pervasive presence in diverse cellular, tissue, and organ settings. This ubiquitous distribution underscores its fundamental involvement in the genesis of pain, making it a central focus in pain-related research. However, recent investigations have unveiled that TRPV1's functional significance transcends the realm of pain modulation, extending its influence to encompass a wide spectrum of physiological and pathological processes. The ambit of TRPV1's influence encompasses not only pain responses but also embraces the intricate domains of nervous system disorders, cancer metastasis, as well as afflictions pertaining to the skin and heart. Moreover, compelling evidence now demonstrates that TRPV1 also wields substantial sway in the domain of digestive diseases, further highlighting its versatility and far-reaching impact on human health. Therefore, this comprehensive review endeavors to delve into the multifaceted roles played by TRPV1 in the various organs constituting the digestive system.

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.

Divergent roles of estrogen receptor subtypes in regulating estrogen-modulated colonic ion transports and epithelial repair

Although it was described previously for estrogen (E2) regulation of intestinal epithelial Cl- and HCO3- secretion in sex difference, almost nothing is known about the roles of estrogen receptor (ER) subtypes in regulating E2-modulated epithelial ion transports and epithelial restitution. Here, we aimed to investigate ERα and ERβ subtypes in the regulation of E2-modulated colonic epithelial HCO3- and Cl- secretion and epithelial restitution. Through physiological and biochemical studies, in combination of genetic knockdown, we showed that ERα attenuated female colonic Cl- secretion but promoted Ca2+-dependent HCO3- secretion via store-operated calcium entry (SOCE) mechanism in mice. However, ERβ attenuated HCO3- secretion by inhibiting Ca2+via the SOCE and inhibiting cAMP via protein kinases. Moreover, ERα but not ERβ promoted epithelial cell restitution via SOCE/Ca2+ signaling. ERα also enhanced cyclin D1, proliferating cell nuclear antigen, and β-catenin expression in normal human colonic epithelial cells. All ERα-mediated biological effects could be attenuated by its selective antagonist and genetic knockdown. Finally, both ERα and ERβ were expressed in human colonic epithelial cells and mouse colonic tissues. We therefore conclude that E2 modulates complex colonic epithelial HCO3- and Cl- secretion via ER subtype-dependent mechanisms and that ERα is specifically responsible for colonic epithelial regeneration. This study provides novel insights into the molecular mechanisms of how ERα and ERβ subtypes orchestrate functional homeostasis of normal colonic epithelial cells.

High expression of GPR176 predicts poor prognosis of gastric cancer patients and promotes the proliferation, migration, and invasion of gastric cancer cells

G-protein-coupled receptors (GPCRs) are the most prominent family of cell surface receptors, which can regulate various biological functions and play an essential role in many diseases. GPR176 is a member of the GPCRs family and has been rarely studied in cancer. We aim to investigate the diagnostic and prognostic value of GPR176 in gastric cancer (GC) and explore its potential mechanism. Through the TCGA database and real-time quantitative PCR, we found that the expression level of GPR176 was significantly increased in GC and had good value in the diagnosis and prognosis of GC. Vitro experiments revealed that GPR176 could promote the proliferation, migration, and invasion of GC cells and may be involved in regulating multiple tumors and immune-related signaling pathways. In addition, we found that GPR176 is associated with GC immune infiltration and may affect the immune efficacy of GC patients. In summary, the high GPR176 expression level was associated with poor prognosis, more robust immune infiltration, and worse immunotherapy efficacy in GC patients, suggesting that GPR176 may be an immune-related biomarker for GC that can promote the proliferation, migration, and invasion of GC cells.

"ThermoTRP" Channel Expression in Cancers: Implications for Diagnosis and Prognosis (Practical Approach by a Pathologist)

Temperature-sensitive transient receptor potential (TRP) channels (so-called "thermoTRPs") are multifunctional signaling molecules with important roles in cell growth and differentiation. Several "thermoTRP" channels show altered expression in cancers, though it is unclear if this is a cause or consequence of the disease. Regardless of the underlying pathology, this altered expression may potentially be used for cancer diagnosis and prognostication. "ThermoTRP" expression may distinguish between benign and malignant lesions. For example, TRPV1 is expressed in benign gastric mucosa, but is absent in gastric adenocarcinoma. TRPV1 is also expressed both in normal urothelia and non-invasive papillary urothelial carcinoma, but no TRPV1 expression has been seen in invasive urothelial carcinoma. "ThermoTRP" expression can also be used to predict clinical outcomes. For instance, in prostate cancer, TRPM8 expression predicts aggressive behavior with early metastatic disease. Furthermore, TRPV1 expression can dissect a subset of pulmonary adenocarcinoma patients with bad prognosis and resistance to a number of commonly used chemotherapeutic agents. This review will explore the current state of this rapidly evolving field with special emphasis on immunostains that can already be added to the armoire of diagnostic pathologists.

TRPV1 Is a Potential Tumor Suppressor for Its Negative Association with Tumor Proliferation and Positive Association with Antitumor Immune Responses in Pan-Cancer

Background

Although numerous studies have shown that the expression and activation of TRPV1 have an important role in cancer development, a comprehensive exploration of associations between TRPV1 expression and tumor proliferation, microenvironment, and clinical outcomes in pan-cancer remains insufficient.

Methods

From The Cancer Genome Atlas (TCGA) program, we downloaded multiomics data of ten cancer cohorts and investigated the correlations between TRPV1 expression and immune signatures' enrichment, stromal content, genomic features, oncogenic signaling, and clinical features in these cancer cohorts and pan-cancer.

Results

Elevated expression of TRPV1 correlated with better clinical outcomes in pan-cancer and diverse cancer types. In multiple cancer types, TRPV1 expression correlated negatively with the expression of tumor proliferation marker genes (MKI67 and RACGAP1), proliferation scores, cell cycle scores, stemness scores, epithelial-mesenchymal transition scores, oncogenic pathways' enrichment, tumor immunosuppressive signals, intratumor heterogeneity, homologous recombination deficiency, tumor mutation burden, and stromal content. Moreover, TRPV1 expression was downregulated in late-stage versus early-stage tumors. In breast cancer, bladder cancer, and low-grade glioma, TRPV1 expression was more inferior in invasive than in noninvasive subtypes. Pathway analysis showed that the enrichment of cancer-associated pathways correlated inversely with TRPV1 expression levels.

Conclusion

TRPV1 upregulation correlates with decreased tumor proliferation, tumor driver gene expression, genomic instability, and tumor immunosuppressive signals in various cancers. Our results provide new understanding of the role of TRPV1 in both cancer biology and clinical practice.

Overexpressed transient receptor potential vanilloid 1 (TRPV1) in lung adenocarcinoma harbours a new opportunity for therapeutic targeting

The specific biological function of transient receptor potential vanilloid 1 (TRPV1) in pathogenesis of lung adenocarcinoma (LUAD) remains unclear. In this study, TRPV1 expression in tumor tissues, primary cells and cell lines of LUAD, as well as the mechanism mediating its hyperexpression were systematically studied. Multiple models and techniques were adopted to elucidate the relationship between TRPV1 hyperexpression and tumor recurrence and metastasis. Results showed that TRPV1 expression was increased in tumor tissues and primary tumor cells of LUAD patients. The increased expression was associated with worse overall survival outcome and raised HIF1α levels. TRPV1 expression in A549 and NCI-H292 cells was increased after pretreatment with cigarette smoke extract or spermine NONOate. Moreover, A549 cells with TRPV1 overexpression has enhanced tumor growth rates in subcutaneous grafted tumor models, and increased intrapulmonary metastasis after tail vein infusion in nude BALB/c nude mice. Mechanistically, TRPV1 overexpression in A549 cells promoted HIF1α expression and nuclear translocation by promoting CREB phosphorylation and activation of NOS1-NO pathway, ultimately leading to accelerated cell proliferation and stronger invasiveness. In addition, based on photothermal effects, CuS-TRPV1 mAb effectively targeted and induced apoptosis of TRPV1-A549 cells both in vivo and in vitro, thereby mitigating tumor growth and metastasis induced by xenotransplantation of TRPV1-A549 cells. In conclusion, TRPV1 hyperexpression in LUAD is a risk factor for tumor progression and is involved in proliferation and migration of tumor cells through activation of HIF1α. Our study also attempted a new strategy inhibiting the recurrence and metastasis of LUAD: by CuS-TRPV1 mAb precisely kill TRPV1 hyperexpression cells through photothermal effects.

NCX1 coupled with TRPC1 to promote gastric cancer via Ca2+/AKT/β-catenin pathway

Plasma membrane Na⁺/Ca²⁺ exchanger 1 (NCX1) is a bidirectional ion transporter to operate in Ca²⁺ entry or exit modes, and TRPC1 is Ca²⁺-permeable channel. Both NCX1 and TRPC1 play critical roles in maintaining cytosolic free Ca²⁺ ([Ca²⁺]_cyt) homeostasis in mammalian cells. Although either TRPC1 channel or Ca²⁺ entry mode of NCX1 is implicated in some tumorigenesis, it has not been explored if a coordination of NCX1 and TRPC1 involves in the pathogenesis of H. pylori-associated human gastric cancer (GC). Here we found the protein expression of NCX1 was significantly enhanced in human GC specimens, which correlated with tumor progression and poor survival in GC patients. TRPC1 and NCX1 were parallelly enhanced, co-localized and bound in human GC cells. By a functional coupling, TRPC1 drives NCX1 to the Ca²⁺ entry mode, raising [Ca²⁺]_cyt in GC cells. Moreover, CaCl₂, H. pylori and their virulence factors all enhanced expressions and activities of NCX1 and TRPC1, and evoked aberrant Ca²⁺ entry to promote proliferation, migration, and invasion of GC cells through AKT/β-catenin pathway. Tumor growth and metastasis also depended on the enhanced expression of NCX1 in subcutaneously xenografted GC mouse model. Overall, our findings indicate that TRPC1/NCX1 coupling may promote H. pylori-associated GC through the Ca²⁺/AKT/β-catenin pathway. Since the Ca²⁺ exit mode and the Ca²⁺ entry mode of NCX1 play different roles under mostly physiological and pathological conditions respectively, targeting TRPC1/NCX1 coupling could be a novel strategy for selectively blocking Ca²⁺ entry mode to potentially treat digestive cancer with less side effect.

Low expression and Hypermethylation of ATP2B1 in Intrahepatic Cholangiocarcinoma Correlated With Cold Tumor Microenvironment

Background

The efficacy of current therapeutic schedule is limited owing to fibroproliferative tumor microenvironment (TME) of cholangiocarcinoma, compelling a search for new therapeutic targets.

Methods

Gene expression profiles and methylation profiles were obtained from UCSC Xena. Consensus clustering was performed on the transcriptome data of cholangiocarcinoma to determine the different immune subtypes. The differentially expressed genes (DEGs) between hot tumor and cold tumors were identified. ESTIMATE was used to assess immune score, and the cases were separated into relatively superior and inferior immune score groups. Single-sample gene set enrichment analysis was applied to assess 28 immune cells in the cholangiocarcinoma microenvironment. Unsupervised consensus was applied for methylation profiling to distribute the high and low methylation groups. The correlation between DNA methylation and mRNA expression was investigated, and the relationship between the ATP2B1 gene and the immune microenvironment was explored. Finally, 77 cases of intrahepatic cholangiocarcinoma (ICC) were collected for verification.

Results

Seven subtypes were related to patient outcomes (P=0.005). The proportions of CD8⁺ T cells in the “hot” immune type was significantly greater than that in the “cold” immune type (P<0.05). Next, DEGs and DNA methylation-governed genes were intersected, and ATP2B1 was identified as a prognosis factor in ICC (P=0.035). ATP2B1 expression was positively correlated with immune scores (P=0.005, r=0.458), the levels of infiltrating CD8⁺ T cells (P=0.004, r=0.47), and CD4⁺ T cells (P=0.027, r=0.37). Immunohistochemistry confirmed that the amounts of CD8⁺ and CD4⁺ T cells were significantly higher in ICC tissue samples than in tissues with ATP2B1 overexpression (P<0.05).

Conclusions

ATP2B1 overexpression can activate immune signals and prompt cold tumor response.

TRPV1 is a potential biomarker for the prediction and treatment of multiple cancers based on a pan-cancer analysis

BACKGROUND

Transient receptor potential cation channel subfamily V member 1 (TRPV1) was considered to play pivotal roles in multiple cancers; however, the expression and clinical significance of the TRPV1 remain unclear, which were explored in this study.

RESULTS

The pan-cancer analysis was performed based on 10,236 samples in 32 cancers. Differential TRPV1 expression levels were detected in 12 cancers (p < 0.05). TRPV1 demonstrated its conspicuous prognosis significance and prediction effects for some cancers (e.g., lung adenocarcinoma), indicating its potential as a valuable and novel biomarker in treating and predicting cancers. TRPV1 expression was relevant to DNA methyltransferases, mismatch repair genes, tumor mutational burden, and microsatellite instability. TRPV1 expression was associated with the immune microenvironment of some cancers, and its roles in different cancers may be mediated by affecting various immune cells. Gene set enrichment analysis discloses the significant relevance of TRPV1 expression with a series of metabolic and immunoregulatory-related pathways.

CONCLUSIONS

This study provided a comprehensive workflow of the expression, clinical significance, and underlying mechanisms of TRPV1 in pan-cancer. TRPV1 may be an underlying biomarker for predicting and treating multiple cancer.

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.

Integrative analysis of TRPV family to prognosis and immune infiltration in renal clear cell carcinoma

The transient receptor potential vanilloid (TRPV) family has been preliminarily discovered to play an important role in various cancers, including clear cell renal cell carcinoma (ccRCC), which is closely associated with immune infiltration. However, the expression and prognosis of TRPV family and tumor-infiltrating immune cells in ccRCC are obscure. This study aimed to explore the prognostic and therapeutic value of the TRPV family expression in ccRCC from the perspective of bioinformatics. We analyzed the transcriptome and clinical data of kidney renal clear cell carcinoma (KIRC) from The Cancer Genome Atlas (TCGA) database. A clustering analysis and immune infiltration analysis were conducted to investigate the influence of the TRPV family genes on ccRCC. Our study found that the TRPV family is an excellent prognostic stratification for ccRCC. Among them, TRPV3 is the most significant prognostic marker of ccRCC. In addition, we performed a drug sensitivity analysis to identify the drugs with the strongest association with TRPV3. As a result, the TRPV family, particularly TRPV3, can act as a prognostic biomarker in ccRCC to determine prognosis and levels of immune infiltration.

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.

A TRP Family Based Signature for Prognosis Prediction in Head and Neck Squamous Cell Carcinoma

Purpose

Head and neck squamous cell carcinoma (HNSCC) is a classical type of head and neck cancers, with heterogeneous clinical outcome. This project is set out to create a robust risk signature based on TRP family genes (TFGs) for prognosis evaluation in HNSCC.

Methods

Based on the HNSCC sample data from the TCGA website, we integrated expression profile of TFGs for 490 HNSCC cases. We explore the interactions among TFGs using STRING tool. The TFGs-based signature (TFBS) was created by Cox relative analyses. In addition, we conducted GSEA to identify the underlying signaling pathways of the specific TFGs in HNSCC. The immune landscape of HNSCC patients was analyzed by CIBERSORT and ssGSEA algorithms.

Results

A total of 6 TFGs (TRPC1, TRPC3, TRPC6, TRPV2, TRPV4, and TRPM8) closely associated with prognosis of HNSCC cases were screened to create TFBS. TFBS predicted that the TFBS-high group presented dismal patient outcome. Cox regression revealed the favorable independent value of TFBS. ROC analysis showed the robust power of TFBS for prognosis forecasting. GSEA determined several crucial pathways related with HNSCC, which are the p53 pathway, TNF-alpha signaling via NFKB, and hypoxia. Moreover, immune-related analysis showed that patients in the TFBS-high group were more likely in immunosuppressive status.

Conclusion

Our proposed TFBS could serve as a favorable indicator to forecast the survival outcome of HNSCC cases and offer prominent therapy guidance.

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.

Evodiamine induces ROS-Dependent cytotoxicity in human gastric cancer cells via TRPV1/Ca2+ pathway

Evodiamine (EVO), a key active ingredient of the fruit of Evodiae fructus, is provided with antitumor effects (mainly cytotoxic effect) including proliferation inhibition, cell cycle arrest, apoptosis, and metastasis inhibition. Our study aims to explain the underlying role of TRPV1/Ca²⁺ in EVO-induced cytotoxicity in human gastric cancer cells. Human gastric cancer line BGC-823 was used to study EVO-induced cytotoxicity. Cell viability was examined using CCK-8 assay. Apoptosis was examined using Annexin V-FITC/PI staining assay. Intracellular ROS ([ROS]i) levels were examined using DCFH-DA assay. Mitochondrial morphology was examined using Mitotracker Green staining. Mitochondrial membrane potential (Δψm) were examined using JC-1 assay. Intracellular Ca²⁺ levels ([Ca²⁺]i) were examined using Fluo-4 AM assay. Mitochondrial ROS ([ROS]m)levels were examined using Mitotracker Green/MitoSOX Red staining. Mitochondrial Ca²⁺ ([Ca²⁺]m)levels were examined using Mitotracker Green/Rhod-2 Red staining. The protein levels was detected by Western blot. EVO exposure causes significant ROS generation and apoptotic cell death. Pretreatment of EUK134 significantly ameliorated EVO-induced apoptotic cell death. Furthermore, EVO exposure induced [ROS]i generation and mitochondrial dysfunction, including [ROS]m generation and Δψm dissipation, which can be significantly attenuated by pre-incubation of rotenone indicating that [ROS]m is the main source of EVO-induced intracellular ROS generation. Importantly, EVO-induced cytotoxicity was significantly ameliorated by intracellular Ca²⁺ chelation, confirming that EVO induces cell death through Ca²⁺ overload. Pharmacological and genetic inhibition of TRPV1 could significantly attenuate Ca²⁺ influx, ROS generation and apoptotic cell death induced by EVO exposure, while exogenous TRPV1 overexpression could augment the EVO-induced cytotoxicity. Moreover, genetic inhibition of mitochondrial calcium uniporter (MCU) attenuated EVO-induced cell death and mitochondrial dysfunction. EVO exposure induced endoplasmic reticulum (ER) stress demonstrated by the activation of PERK/CHOP in cells exposed to EVO, and PERK/CHOP activation was depleted by EUK134 pre-treatment. Our results support the concept that EVO induces ROS-dependent cytotoxicity via TRPV1/Ca²⁺ Pathway.

FHOD1 is upregulated in gastric cancer and promotes the proliferation and invasion of gastric cancer cells

Gastric cancer (GC) is one of the main causes of cancer-associated morbidity and mortality worldwide. The present study aimed to investigate the role of the gene encoding formin homology 2 domain containing 1 (FHOD1) protein in GC development. Data from The Cancer Genome Atlas were firstly analyzed, and immunohistochemistry was conducted on GC tissues. The results demonstrated that FHOD1 expression in GC tissues was significantly increased compared with adjacent non-tumor tissues. Furthermore, the expression level of FHOD1 was negatively associated with the overall survival of patients with GC. For the functional studies, lentivirus-mediated short hairpin RNA against FHOD1 and FHOD1-overexpression vectors were constructed to knockdown and overexpress the expression level of FHOD1 in human GC cell lines, respectively. The results indicated that FHOD1 knockdown inhibited the proliferation, colony formation and migratory and invasive abilities of GC cells. Conversely, overexpression of FHOD1 in GC cells promoted soft-agar colony formation and migratory and invasive abilities. In addition, it was demonstrated that genes of which expression levels were correlated with FHOD1 were enriched in the Gene Ontology term of 'extracellular matrix (ECM) structural constituent', suggesting that FHOD1 may serve an important role in the regulation of ECM. In conclusion, the present study demonstrated that FHOD1 may exert an oncogenic role in cultured GC cells and be inversely associated with the overall survival of patients with GC.

Epigenetic regulation of ion channels in the sense of taste

There are five fundamental tastes discovered so far: sweet, bitter, umami, sour and salty. Taste is mediated by the specialized neuroepithelial cells mainly located at the tongue papillae, namely taste receptor cells, which can be classified into type I, type II, type III and type IV. Ion channels are necessary for diverse cell physiological activities including taste sensing, smell experience and temperature perception. Existing evidences have demonstrated distinct structures and working models of ion channels. Epigenetic modifications regulate gene expression mainly through histone modifications, DNA methylation and non-coding RNA-mediated regulation, without altering DNA sequence. This review summarizes how ion channels work during the transduction of multiple tastes, as well as the recent progressions in the epigenetic regulation of ion channels.

Advances in the study of cancer metastasis and calcium signaling as potential therapeutic targets

Metastasis is still the primary cause of cancer-related mortality. However, the underlying mechanisms of cancer metastasis are not yet fully understood. Currently, the epithelial-mesenchymal transition, metabolic remodeling, cancer cell intercommunication and the tumor microenvironment including diverse stromal cells, are reported to affect the metastatic process of cancer cells. Calcium ions (Ca²⁺) are ubiquitous second messengers that manipulate cancer metastasis by affecting signaling pathways. Diverse transporter/pump/channel-mediated Ca²⁺ currents form Ca²⁺ oscillations that can be decoded by Ca²⁺-binding proteins, which are promising prognostic biomarkers and therapeutic targets of cancer metastasis. This paper presents a review of the advances in research on the mechanisms underlying cancer metastasis and the roles of Ca²⁺-related signals in these events.

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.