The overexpressed functional transient receptor potential channel TRPM2 in oral squamous cell carcinoma

Connecting the dots: investigating the link between environmental, genetic, and epigenetic influences in metabolomic alterations in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) accounts for around 90% of all oral cancers and is the eighth most common cancer worldwide. Despite progress in managing OSCC, the overall prognosis remains poor, with a survival rate of around 50-60%, largely due to tumor size and recurrence. The challenges of late-stage diagnosis and limitations in current methods emphasize the urgent need for less invasive techniques to enable early detection and treatment, crucial for improving outcomes in this aggressive form of oral cancer. Research is currently aimed at unraveling tumor-specific metabolite profiles to identify candidate biomarkers as well as discover underlying pathways involved in the onset and progression of cancer that could be used as new targets for diagnostic and therapeutic purposes. Metabolomics is an advanced technological approach to identify metabolites in different sample types (biological fluids and tissues). Since OSCC promotes metabolic reprogramming influenced by a combination of genetic predisposition and environmental factors, including tobacco and alcohol consumption, and viral infections, the identification of distinct metabolites through screening may aid in the diagnosis of this condition. Moreover, studies have shown the use of metabolites during the catalysis of epigenetic modification, indicating a link between epigenetics and metabolism. In this review, we will focus on the link between environmental, genetic, and epigenetic influences in metabolomic alterations in OSCC. In addition, we will discuss therapeutic targets of tumor metabolism, which may prevent oral tumor growth, metastasis, and drug resistance.

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.

Immune Escape Strategies in Head and Neck Cancer: Evade, Resist, Inhibit, Recruit

Head and neck cancers (HNCs) arise from the mucosal lining of the aerodigestive tract and are often associated with alcohol use, tobacco use, and/or human papillomavirus (HPV) infection. Over 600,000 new cases of HNC are diagnosed each year, making it the sixth most common cancer worldwide. Historically, treatments have included surgery, radiation, and chemotherapy, and while these treatments are still the backbone of current therapy, several immunotherapies have recently been approved by the Food and Drug Administration (FDA) for use in HNC. The role of the immune system in tumorigenesis and cancer progression has been explored since the early 20th century, eventually coalescing into the current three-phase model of cancer immunoediting. During each of the three phases-elimination, equilibrium, and escape-cancer cells develop and utilize multiple strategies to either reach or remain in the final phase, escape, at which point the tumor is able to grow and metastasize with little to no detrimental interference from the immune system. In this review, we summarize the many strategies used by HNC to escape the immune system, which include ways to evade immune detection, resist immune cell attacks, inhibit immune cell functions, and recruit pro-tumor immune cells.

Knockdown of TRPM2 promotes osteogenic differentiation of human periodontal ligament stem cells by modulating NF-κB /NLRP3 pathway

Periodontitis is characterized by periodontal destruction triggered by chronic inflammation. The optimal treatment for periodontitis is to improve the periodontal microenvironment, reduce inflammation and achieve periodontal regeneration. Recently, the role of TRPM2 in inflammatory diseases has been reported. However, the function of TRPM2 in periodontal disease and the biological mechanism remain elusive. Therefore, this study aimed to identify the role and explore the underlying mechanisms of TRPM2 in periodontal disease. Here, we first identified the characterization of human periodontal ligament stem cells (PDLSCs). Oil Red O Staining and Alizarin Red mineralized matrix were used to evaluate the multi-differentiation capacity of cells. Flow cytometry was employed to detect MSC-specific surface markers of hPDLSCs. hPDLSCs were treated with 0, 5, 10 or 40 μg/mL of TNF-α for 72 h. Western blot assay were performed to examine the expression of Transient receptor potential cation channel, subfamily M, member 2 (TRPM2) in hPDLSCs. CCK8 and colony formation assays were used to detect the cell viability and proliferation of hPDLSCs, which revealed that TRPM2 knockdown promoted hPDLSCs proliferation. Then, ALP activity in hPDLSCs was detected by ALP activity detection kit. Next, the expression of ALP and Runx2 in hPDLSCs was detected by immunofluorescence staining. The result showed that TRPM2 knockdown promoted osteogenic differentiation and affected the genes expression of osteogenic. Finally, the expressions of p-p65, p65, p-IκBα, IκBα and NLRP3 in hPDLSCs were detected by western blot assay. Together, these results suggested that knockdown of TRPM2 accelerated osteogenic differentiation of hPDLSCs through mediating NF-κB /NLRP3 pathway.

TRP Channels in Tumoral Processes Mediated by Oxidative Stress and Inflammation

The channels from the superfamily of transient receptor potential (TRP) activated by reactive oxygen species (ROS) can be defined as redox channels. Those with the best exposure of the cysteine residues and, hence, the most sensitive to oxidative stress are TRPC4, TRPC5, TRPV1, TRPV4, and TRPA1, while others, such as TRPC3, TRPM2, and TRPM7, are indirectly activated by ROS. Furthermore, activation by ROS has different effects on the tumorigenic process: some TRP channels may, upon activation, stimulate proliferation, apoptosis, or migration of cancer cells, while others inhibit these processes, depending on the cancer type, tumoral microenvironment, and, finally, on the methods used for evaluation. Therefore, using these polymodal proteins as therapeutic targets is still an unmet need, despite their draggability and modulation by simple and mostly unharmful compounds. This review intended to create some cellular models of the interaction between oxidative stress, TRP channels, and inflammation. Although somewhat crosstalk between the three actors was rather theoretical, we intended to gather the recently published data and proposed pathways of cancer inhibition using modulators of TRP proteins, hoping that the experimental data corroborated clinical information may finally bring the results from the bench to the bedside.

TRPM2 Channels: A Potential Therapeutic Target in Melanoma?

The transient receptor potential, the melastatin (TRPM) subfamily, which consists of eight known members, appears to have significant importance in melanoma progression, treatment, and prognosis. As several members were originally cloned from cancerous tissue, initial studies aimed towards identifying TRPM involvement in cancer progression and tumorigenesis. For relevance in skin cancer, previous research has shown roles for several TRPM members in skin cancer progression, growth, and patient prognosis. One unique member, TRPM2, appears to have notable therapeutic potential in the treatment of melanoma. Previous and recent studies have demonstrated increased TRPM2 expression levels in melanoma, as well as important roles for TRPM2 in melanoma growth, proliferation, and survival. TRPM2 is thus an emerging target in the treatment of melanoma, where TRPM2 antagonism may offer an additional treatment option for melanoma patients in the future.

TRPM2-mediated Ca2+ signaling as a potential therapeutic target in cancer treatment: an updated review of its role in survival and proliferation of cancer cells

The transient receptor potential melastatin subfamily member 2 (TRPM2), a thermo and reactive oxygen species (ROS) sensitive Ca²⁺-permeable cation channel has a vital role in surviving the cell as well as defending the adaptability of various cell groups during and after oxidative stress. It shows higher expression in several cancers involving breast, pancreatic, prostate, melanoma, leukemia, and neuroblastoma, indicating it raises the survivability of cancerous cells. In various cancers including gastric cancers, and neuroblastoma, TRPM2 is known to conserve viability, and several underlying mechanisms of action have been proposed. Transcription factors are thought to activate TRPM2 channels, which is essential for cell proliferation and survival. In normal physiological conditions with an optimal expression of TRPM2, mitochondrial ROS is produced in optimal amounts while regulation of antioxidant expression is carried on. Depletion of TRPM2 overexpression or activity has been shown to improve ischemia-reperfusion injury in organ levels, reduce tumor growth and/or viability of various malignant cancers like breast, gastric, pancreatic, prostate, head and neck cancers, melanoma, neuroblastoma, T-cell and acute myelogenous leukemia. This updated and comprehensive review also analyzes the mechanisms by which TRPM2-mediated Ca²⁺ signaling can regulate the growth and survival of different types of cancer cells. Based on the discussion of the available data, it can be concluded that TRPM2 may be a unique therapeutic target in the treatment of several types of cancer. Video Abstract.

"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.

Ion Channels as Potential Tools for the Diagnosis, Prognosis, and Treatment of HPV-Associated Cancers

The human papilloma virus (HPV) group comprises approximately 200 genetic types that have a special affinity for epithelial tissues and can vary from producing benign symptoms to developing into complicated pathologies, such as cancer. The HPV replicative cycle affects various cellular and molecular processes, including DNA insertions and methylation and relevant pathways related to pRb and p53, as well as ion channel expression or function. Ion channels are responsible for the flow of ions across cell membranes and play very important roles in human physiology, including the regulation of ion homeostasis, electrical excitability, and cell signaling. However, when ion channel function or expression is altered, the channels can trigger a wide range of channelopathies, including cancer. In consequence, the up- or down-regulation of ion channels in cancer makes them attractive molecular markers for the diagnosis, prognosis, and treatment of the disease. Interestingly, the activity or expression of several ion channels is dysregulated in HPV-associated cancers. Here, we review the status of ion channels and their regulation in HPV-associated cancers and discuss the potential molecular mechanisms involved. Understanding the dynamics of ion channels in these cancers should help to improve early diagnosis, prognosis, and treatment in the benefit of HPV-associated cancer patients.

On the modulation of TRPM channels: Current perspectives and anticancer therapeutic implications

The transient melastatin receptor potential (TRPM) ion channel subfamily functions as cellular sensors and transducers of critical biological signal pathways by regulating ion homeostasis. Some members of TRPM have been cloned from cancerous tissues, and their abnormal expressions in various solid malignancies have been correlated with cancer cell growth, survival, or death. Recent evidence also highlights the mechanisms underlying the role of TRPMs in tumor epithelial-mesenchymal transition (EMT), autophagy, and cancer metabolic reprogramming. These implications support TRPM channels as potential molecular targets and their modulation as an innovative therapeutic approach against cancer. Here, we discuss the general characteristics of the different TRPMs, focusing on current knowledge about the connection between TRPM channels and critical features of cancer. We also cover TRPM modulators used as pharmaceutical tools in biological trials and an indication of the only clinical trial with a TRPM modulator about cancer. To conclude, the authors describe the prospects for TRPM channels in oncology.

Label-free LC-MS/MS proteomics analyses reveal CLIC1 as a predictive biomarker for bladder cancer staging and prognosis

Introduction

Bladder cancer (BC) is a significant carcinoma of the urinary system that has a high incidence of morbidity and death owing to the challenges in accurately identifying people with early-stage BC and the lack of effective treatment options for those with advanced BC. Thus, there is a need to define new markers of prognosis and prediction.

Methods

In this study, we have performed a comprehensive proteomics experiment by label-free quantitative proteomics to compare the proteome changes in the serum of normal people and bladder cancer patients-the successful quantification of 2064 Quantifiable proteins in total. A quantitative analysis was conducted to determine the extent of changes in protein species' relative intensity and reproducibility. There were 43 upregulated proteins and 36 downregulated proteins discovered in non-muscle invasive bladder cancer and normal individuals. Sixty-four of these proteins were elevated, and 51 were downregulated in muscle-invasive and non-muscle-invasive bladder cancer, respectively. Functional roles of differentially expressed proteins were annotated using Gene Ontology (GO) and Clusters of Orthologous Groups of Proteins (COG). To analyze the functions and pathways enriched by differentially expressed proteins, GO enrichment analysis, protein domain analysis, and KEGG pathway analysis were performed. The proteome differences were examined and visualized using radar plots, heat maps, bubble plots, and Venn diagrams.

Results

As a result of combining the Venn diagram with protein-protein interactions (PPIs), Chloride intracellular channel 1 (CLIC1) was identified as the primary protein. Using the Gene Set Cancer Analysis (GSCA) website, the influence of CLIC1 on immune infiltration was analyzed. A negative correlation between CD8 naive and CLIC1 levels was found. For validation, immunohistochemical (IHC), qPCR, and western blotting (WB) were performed.Further, we found that CLIC1 was associated with a poor prognosis of bladder cancer in survival analysis.

Discussion

Our research screened CLIC1 as a tumor-promoting protein in bladder cancer for the first time using serum mass spectrometry. And CLIC1 associated with tumor stage, and immune infiltrate. The prognostic biomarker and therapeutic target CLIC1 may be new for bladder cancer patients.

Overexpression of transient receptor potential melastatin 6 during human oral squamous cell carcinogenesis

Background/purpose

Transient receptor potential melastatin (TRPM) channel is involved in cell proliferation and cell survival. Eight members (TRPM1-8) are within the TRPM subfamily. The current study is aimed to investigate TRPM6 expression in human oral carcinogenesis.

Materials and methods

Sixty-six oral squamous cell carcinomas (OSCCs), 47 oral potentially malignant disorders (OPMD) with moderate-severe epithelial dysplasia (ED), 28 OPMD with mild ED, and 33 normal oral mucosa (NOM) samples were subjected to immunohistochemical staining. Two human oral cancer cell lines (OCCLs), an oral premalignant cell line (DOK), and a normal oral keratinocyte culture (HOK) were used for Western blot analysis. OCCLs were evaluated for proliferation, migration, invasion assays, and intracellular calcium concentration.

Results

TRPM6 protein expression in OSCC was significantly increased as compared with normal samples. Protein expression of TRPM6 in OCCLs was significantly higher as compared with HOK. Significant decreases in degrees of proliferation, migration, invasion, and intracellular calcium concentration were noted in OCCLs with TRPM6 siRNA transfection as compared with those without transfection. Significantly increased TRPM6 protein level was noted in OPMD with moderate-severe ED as compared with those with mild ED.

Conclusion

Our results implicate that TRPM6 overexpression is potentially related to human oral carcinogenesis.

Methods for Investigating Transient Receptor Potential Melastatin-2 (TRPM2): A Cation Channel Activated by ADP-Ribose and Involved in Cell Death

Transient receptor potential melastatin-2 (TRPM2) is an emerging chemotherapeutic target due to its involvement in poly(ADP-ribose) metabolism and the ability to induce anticancer effects after antagonism of its functions. Normally functioning as a nonspecific cation channel that is activated by free ADP-ribose, TRPM2 is involved with many cellular processes, including the induction of cell death after oxidative stress. What is becoming clear is that antagonism of TRPM2 selectively induces anticancer effects in several types of cancer. We previously demonstrated decreased growth and proliferation, increased levels of DNA damage, and the selective induction of cell death in breast cancer and melanoma cells. Due to these effects, it appears that TRPM2 has a novel role in cancer cells. Further, this novel role appears to involve nuclear function, because our studies, as well as those from other independent groups, demonstrate a nuclear localization of TRPM2 in various types of cancers. Thus, as an emerging therapeutic target, it is important to describe research techniques that can be utilized to analyze TRPM2 function, determine its effects in cancerous and noncancerous cells, and provide molecular biological methods to inhibit or downregulate its function.

Silencing TRPM2 enhanced erastin- and RSL3-induced ferroptosis in gastric cancer cells through destabilizing HIF-1α and Nrf2 proteins

Ferroptosis is a regulated form of cell death driven by small molecules or conditions that induce lipid-based reactive oxygen species (ROS) accumulation. Cation channel transient receptor potential melastatin-2 (TRPM2) is crucial for cancer cell survival. Our bioinformatic analysis revealed that TRPM2 is associated with cellular responses to chemical stimulus and oxidative stress, implying the potential role of TRPM2 in ferroptosis. Gastric cancer cells were treated with the ferroptosis-inducer, Erastin and RSL3. siRNA transfection was used to silence TRPM2. The levels of GSH, Fe2+, ROS and lipid peroxidation, and the activity of GPx activity were evaluated by flow cytometry and spectrophotometer. The effect of TRPM2 on ubiquitination of HIF-1α and Nrf2 were evaluated by co-immunoprecipitation. Erastin and RSL3 induced the up-regulation of TRPM2 in gastric cancer cell lines, especially in SGC7901 and MGC803. These two cells also showed stronger resistance to Erastin and RSL3 than the other cell lines. TRPM2 knockdown reduced the concentration of GSH and GPx activity, but enhanced the concentration of Fe2+, ROS and lipid peroxidation, which are significant indicators of ferroptosis. Importantly, silencing TRPM2 enhanced the inhibitory effects of Erastin and RSL3 on gastric cancer cell viability, migration, and invasion. TRPM2 stabilized and finally elevated the abundance of HIF-1α and Nrf2 in SGC7901 and MGC803 cells upon Erastin and RSL3. Activation of HIF-1α impaired Erastin- and RSL3-induced ferroptosis after TRPM2 knockdown. Collectively, silencing TRPM2 enhanced Erastin- and RSL3-induced ferroptosis in gastric cancer cells through destabilizing HIF-1α and Nrf2 proteins.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-022-00545-z.

Ca2+ Signalling and Hypoxia/Acidic Tumour Microenvironment Interplay in Tumour Progression

Solid tumours are characterised by an altered microenvironment (TME) from the physicochemical point of view, displaying a highly hypoxic and acidic interstitial fluid. Hypoxia results from uncontrolled proliferation, aberrant vascularization and altered cancer cell metabolism. Tumour cellular apparatus adapts to hypoxia by altering its metabolism and behaviour, increasing its migratory and metastatic abilities by the acquisition of a mesenchymal phenotype and selection of aggressive tumour cell clones. Extracellular acidosis is considered a cancer hallmark, acting as a driver of cancer aggressiveness by promoting tumour metastasis and chemoresistance via the selection of more aggressive cell phenotypes, although the underlying mechanism is still not clear. In this context, Ca2+ channels represent good target candidates due to their ability to integrate signals from the TME. Ca2+ channels are pH and hypoxia sensors and alterations in Ca2+ homeostasis in cancer progression and vascularization have been extensively reported. In the present review, we present an up-to-date and critical view on Ca2+ permeable ion channels, with a major focus on TRPs, SOCs and PIEZO channels, which are modulated by tumour hypoxia and acidosis, as well as the consequent role of the altered Ca2+ signals on cancer progression hallmarks. We believe that a deeper comprehension of the Ca2+ signalling and acidic pH/hypoxia interplay will break new ground for the discovery of alternative and attractive therapeutic targets.

The 'Danse Macabre'-Neutrophils the Interactive Partner Affecting Oral Cancer Outcomes

Over the past few decades, tremendous advances in the prevention, diagnosis, and treatment of cancer have taken place. However for head and neck cancers, including oral cancer, the overall survival rate is below 50% and they remain the seventh most common malignancy worldwide. These cancers are, commonly, aggressive, genetically complex, and difficult to treat and the delay, which often occurs between early recognition of symptoms and diagnosis, and the start of treatment of these cancers, is associated with poor prognosis. Cancer development and progression occurs in concert with alterations in the surrounding stroma, with the immune system being an essential element in this process. Despite neutrophils having major roles in the pathology of many diseases, they were thought to have little impact on cancer development and progression. Recent studies are now challenging this notion and placing neutrophils as central interactive players with other immune and tumor cells in affecting cancer pathology. This review focuses on how neutrophils and their sub-phenotypes, N1, N2, and myeloid-derived suppressor cells, both directly and indirectly affect the anti-tumor and pro-tumor immune responses. Emphasis is placed on what is currently known about the interaction of neutrophils with myeloid innate immune cells (such as dendritic cells and macrophages), innate lymphoid cells, natural killer cells, and fibroblasts to affect the tumor microenvironment and progression of oral cancer. A better understanding of this dialog will allow for improved therapeutics that concurrently target several components of the tumor microenvironment, increasing the possibility of constructive and positive outcomes for oral cancer patients. For this review, PubMed, Web of Science, and Google Scholar were searched for manuscripts using keywords and combinations thereof of "oral cancer, OSCC, neutrophils, TANs, MDSC, immune cells, head and neck cancer, and tumor microenvironment" with a focus on publications from 2018 to 2021.

Antagonism of the transient receptor potential melastatin‑2 channel leads to targeted antitumor effects in primary human malignant melanoma cells

Melanoma continues to be the most aggressive and devastating form of skin cancer for which the development of novel therapies is required. The present study aimed to determine the effects of antagonism of the transient receptor potential melastatin‑2 (TRPM2) ion channel in primary human malignant melanoma cells. TRPM2 antagonism via use of the antifungal agent, clotrimazole, led to decreases in cell proliferation, as well as dose‑dependent increases in cell death in all melanoma cell lines investigated. The targeting of TRPM2 channels was verified using TRPM2 knockdown, where treatment with TRPM2 small‑interfering RNA led to similar levels of cell death in all melanoma cell lines when compared with clotrimazole treatment. Minimal effects on proliferation and cell death were observed following antagonism or knockdown of TRPM2 in non‑cancerous human keratinocytes. Moreover, characteristics of TRPM2 were explored in these melanoma cells and the results demonstrated that TRPM2, localized to the plasma membrane as a non‑specific ion channel in non‑cancerous cells, displayed a nuclear localization in all human melanoma cell lines analyzed. Additional characterization of these melanoma cell lines confirmed that each expressed one or more established multidrug resistance genes. Results of the present study therefore indicated that antagonism of the TRPM2 channel led to antitumor effects in human melanoma cells, including those that are potentially unresponsive to current treatments due to the expression of drug resistance genes. The unique cellular localization of TRPM2 and the specificity of the antitumor effects elicited by TRPM2 antagonism suggested that TRPM2 possesses a unique role in melanoma cells. Collectively, the targeting of TRPM2 represents a potentially novel, efficacious and readily accessible treatment option for patients with melanoma.

Alterations in the Ca2+ toolkit in oesophageal adenocarcinoma

Aim:

To investigate alterations in transcription of genes, encoding Ca²⁺ toolkit proteins, in oesophageal adenocarcinoma (OAC) and to assess associations between gene expression, tumor grade, nodal-metastatic stage, and patient survival.

Methods:

The expression of 275 transcripts, encoding components of the Ca²⁺ toolkit, was analyzed in two OAC datasets: the Cancer Genome Atlas [via the University of Alabama Cancer (UALCAN) portal] and the oesophageal-cancer, clinical, and molecular stratification [Oesophageal Cancer Clinical and Molecular Stratification (OCCAMS)] dataset. Effects of differential expression of these genes on patient survival were determined using Kaplan-Meier log-rank tests. OAC grade- and metastatic-stage status was investigated for a subset of genes. Adjustment for the multiplicity of testing was made throughout.

Results:

Of the 275 Ca²⁺-toolkit genes analyzed, 75 displayed consistent changes in expression between OAC and normal tissue in both datasets. The channel-encoding genes, N-methyl-D-aspartate receptor 2D (GRIN2D), transient receptor potential (TRP) ion channel classical or canonical 4 (TRPC4), and TRP ion channel melastatin 2 (TRPM2) demonstrated the greatest increase in expression in OAC in both datasets. Nine genes were consistently upregulated in both datasets and were also associated with improved survival outcomes. The 6 top-ranking genes for the weighted significance of altered expression and survival outcomes were selected for further analysis: voltage-gated Ca²⁺ channel subunit α 1D (CACNA1D), voltage-gated Ca²⁺ channel auxiliary subunit α2 δ4 (CACNA2D4), junctophilin 1 (JPH1), acid-sensing ion channel 4 (ACCN4), TRPM5, and secretory pathway Ca²⁺ ATPase 2 (ATP2C2). CACNA1D, JPH1, and ATP2C2 were also upregulated in advanced OAC tumor grades and nodal-metastatic stages in both datasets.

Conclusions:

This study has unveiled alterations of the Ca²⁺ toolkit in OAC, compared to normal tissue. Such Ca²⁺ signalling findings are consistent with those from studies on other cancers. Genes that were consistently upregulated in both datasets might represent useful markers for patient diagnosis. Genes that were consistently upregulated, and which were associated with improved survival, might be useful markers for patient outcome. These survival-associated genes may also represent targets for the development of novel chemotherapeutic agents.

A novel strategy for treating cancer: understanding the role of Ca2+ signaling from nociceptive TRP channels in regulating cancer progression

Cancer is an aging-associated disease and caused by genomic instability that is driven by the accumulation of mutations and epimutations in the aging process. Although Ca²⁺ signaling, reactive oxygen species (ROS) accumulation, DNA damage response (DDR) and senescence inflammation response (SIR) are processed during genomic instability, the underlying mechanism for the cause of genomic instability and cancer development is still poorly understood and needs to be investigated. Nociceptive transient receptor potential (TRP) channels, which firstly respond to environmental stimuli, such as microbes, chemicals or physical injuries, potentiate regulation of the aging process by Ca²⁺ signaling. In this review, the authors provide an explanation of the dual role of nociceptive TRP channels in regulating cancer progression, initiating cancer progression by aging-induced genomic instability, and promoting malignancy by epigenetic regulation. Thus, therapeutically targeting nociceptive TRP channels seems to be a novel strategy for treating cancers.

TRPM2 Non-Selective Cation Channels in Liver Injury Mediated by Reactive Oxygen Species

TRPM2 channels admit Ca²⁺ and Na⁺ across the plasma membrane and release Ca²⁺ and Zn²⁺ from lysosomes. Channel activation is initiated by reactive oxygen species (ROS), leading to a subsequent increase in ADP-ribose and the binding of ADP-ribose to an allosteric site in the cytosolic NUDT9 homology domain. In many animal cell types, Ca²⁺ entry via TRPM2 channels mediates ROS-initiated cell injury and death. The aim of this review is to summarise the current knowledge of the roles of TRPM2 and Ca²⁺ in the initiation and progression of chronic liver diseases and acute liver injury. Studies to date provide evidence that TRPM2-mediated Ca²⁺ entry contributes to drug-induced liver toxicity, ischemia–reperfusion injury, and the progression of non-alcoholic fatty liver disease to cirrhosis, fibrosis, and hepatocellular carcinoma. Of particular current interest are the steps involved in the activation of TRPM2 in hepatocytes following an increase in ROS, the downstream pathways activated by the resultant increase in intracellular Ca²⁺, and the chronology of these events. An apparent contradiction exists between these roles of TRPM2 and the role identified for ROS-activated TRPM2 in heart muscle and in some other cell types in promoting Ca²⁺-activated mitochondrial ATP synthesis and cell survival. Inhibition of TRPM2 by curcumin and other “natural” compounds offers an attractive strategy for inhibiting ROS-induced liver cell injury. In conclusion, while it has been established that ROS-initiated activation of TRPM2 contributes to both acute and chronic liver injury, considerable further research is needed to elucidate the mechanisms involved, and the conditions under which pharmacological inhibition of TRPM2 can be an effective clinical strategy to reduce ROS-initiated liver injury.

Light-controlled calcium signalling in prostate cancer and benign prostatic hyperplasia

Background

Identifying ways to reduce the burden of prostate cancer (Pca) or benign prostatic hyperplasia (BPH) is a top research priority. It is a typical entanglement seen in men which is portrayed by trouble in micturition. It stands as a significant problem in our society. Different molecular biomarker has high potential to treat Pca or BPH but also causes serious side effects during treatment.

Main text

The role of calcium signalling in the alteration of different biomarkers of Pca or BPH is important. Therefore, the photoswitch drugs may hold the potential to rebalance the altered calcium signaling cascade and the biomarker levels. Thereby play a significant role in the management of Pca and BPH. Online literature searches such as PubMed, Web of Science, Scopus, and Google Scholar were carried out. The search terms used for this review were photo-pharmacology, photo-switch drug, photodynamic therapy, calcium signalling, etc. Present treatment of Pca or BPH shows absence of selectivity and explicitness which may additionally result in side effects. The new condition of the calcium flagging may offer promising outcomes in restoring the present issues related with prostate malignancy and BPH treatment.

Conclusion

The light-switching calcium channel blockers aim to solve this issue by incorporating photo-switchable calcium channel blockers that may control the signalling pathway related to proliferation and metastasis in prostate cancer without any side effects.

Graphical abstract

Schematic diagram explaining the proposed role of photo-switch therapy in curbing the side effects of active drugs in Pca (prostate cancer) and BPH (benign prostatic hyperplasia). a) Delivery of medication by ordinary strategies and irreversible phototherapy causes side effects during treatment. Utilization of photo-switch drug to control the dynamic and inert condition of the medication can cause the medication impacts as we required in prostate cancer and BPH. b) Support of harmony between the calcium signaling is essential to guarantee ordinary physiology. Increment or abatement in the dimensions of calcium signaling can result in changed physiology. c) Major factors involved in the pathogenesis of BPH; downregulation of vitamin D receptor (VDR) and histone deacetylase (HDAC) can prevent BPH. Similarly, downregulation of α-1 adrenoceptor can reduce muscle contraction, while overexpression of β-3 adrenoceptor in BPH can promote further muscle relaxation in BPH treatment therapy. Inhibition of overexpressed biomarkers in BPH TRPM2-1: transient receptor potential cation channel subfamily M member 1; TRPM2-2: transient receptor potential cation channel subfamily M member 2; Androgens; CXCL5: C-X-C motif chemokine ligand 5; TGFβ-1: transforming growth factor β-1; TXA2; thromboxane-2; NMDA: N-methyl-d-aspartate can be the potential target in BPH therapy.

Roles of NAD+ and Its Metabolites Regulated Calcium Channels in Cancer

Nicotinamide adenine dinucleotide (NAD⁺) is an essential cofactor for redox enzymes, but also moonlights as a regulator for ion channels, the same as its metabolites. Ca²⁺ homeostasis is dysregulated in cancer cells and affects processes such as tumorigenesis, angiogenesis, autophagy, progression, and metastasis. Herein, we summarize the regulation of the most common calcium channels (TRPM2, TPCs, RyRs, and TRPML1) by NAD⁺ and its metabolites, with a particular focus on their roles in cancers. Although the mechanisms of NAD⁺ metabolites in these pathological processes are yet to be clearly elucidated, these ion channels are emerging as potential candidates of alternative targets for anticancer therapy.

Transient Receptor Potential (TRP) Channels in Head-and-Neck Squamous Cell Carcinomas: Diagnostic, Prognostic, and Therapeutic Potentials

Head-and-neck squamous cell carcinomas (HNSCC) remain a leading cause of cancer morbidity and mortality worldwide. This is a largely preventable disease with smoking, alcohol abuse, and human papilloma virus (HPV) being the main risk factors. Yet, many patients are diagnosed with advanced disease, and no survival improvement has been seen for oral SCC in the past decade. Clearly, new diagnostic and prognostic markers are needed for early diagnosis and to guide therapy. Gene expression studies implied the involvement of transient receptor potential (TRP) channels in the pathogenesis of HNSCC. TRPs are expressed in normal epithelium where they play a key role in proliferation and differentiation. There is increasing evidence that the expression of TRP channels may change in HNSCC with important implications for diagnosis, prognosis, and therapy. In this review, we propose that TRP channel expression may afford a novel opportunity for early diagnosis of HNSCC and targeted molecular treatment.

Novel Therapeutic Approaches of Ion Channels and Transporters in Cancer

The expression and function of many ion channels and transporters in cancer cells display major differences in comparison to those from healthy cells. These differences provide the cancer cells with advantages for tumor development. Accordingly, targeting ion channels and transporters have beneficial anticancer effects including inhibition of cancer cell proliferation, migration, invasion, metastasis, tumor vascularization, and chemotherapy resistance, as well as promoting apoptosis. Some of the molecular mechanisms associating ion channels and transporters with cancer include the participation of oxidative stress, immune response, metabolic pathways, drug synergism, as well as noncanonical functions of ion channels. This diversity of mechanisms offers an exciting possibility to suggest novel and more effective therapeutic approaches to fight cancer. Here, we review and discuss most of the current knowledge suggesting novel therapeutic approaches for cancer therapy targeting ion channels and transporters. The role and regulation of ion channels and transporters in cancer provide a plethora of exceptional opportunities in drug design, as well as novel and promising therapeutic approaches that may be used for the benefit of cancer patients.

Different regulation of PARP1, PARP2, PARP3 and TRPM2 genes expression in acute myeloid leukemia cells

Background

Acute myeloid leukemia (AML) is a heterogenic lethal disorder characterized by the accumulation of abnormal myeloid progenitor cells in the bone marrow which results in hematopoietic failure. Despite various efforts in detection and treatment, many patients with AML die of this cancer. That is why it is important to develop novel therapeutic options, employing strategic target genes involved in apoptosis and tumor progression.

Methods

The aim of the study was to evaluate PARP1, PARP2, PARP3, and TRPM2 gene expression at mRNA level using qPCR method in the cells of hematopoietic system of the bone marrow in patients with acute myeloid leukemia, bone marrow collected from healthy patients, peripheral blood of healthy individuals, and hematopoietic stem cells from the peripheral blood after mobilization.

Results

The results found that the bone marrow cells of the patients with acute myeloid leukemia (AML) show overexpression of PARP1 and PARP2 genes and decreased TRPM2 gene expression. In the hematopoietic stem cells derived from the normal marrow and peripheral blood after mobilization, the opposite situation was observed, i.e. TRPM2 gene showed increased expression while PARP1 and PARP2 gene expression was reduced. We observed positive correlations between PARP1, PARP2, PARP3, and TRPM2 genes expression in the group of mature mononuclear cells derived from the peripheral blood and in the group of bone marrow-derived cells. In AML cells significant correlations were not observed between the expression of the examined genes. In addition, we observed that the reduced expression of TRPM2 and overexpression of PARP1 are associated with a shorter overall survival of patients, indicating the prognostic significance of these genes expression in AML.

Conclusions

Our research suggests that in physiological conditions in the cells of the hematopoietic system there is mutual positive regulation of PARP1, PARP2, PARP3, and TRPM2 genes expression. PARP1, PARP2, and TRPM2 genes at mRNA level deregulate in acute myeloid leukemia cells.

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.

Role of CD44 in tumor-initiating cells of salivary gland pleomorphic adenoma: More than a surface biomarker

CD44, a cell-surface glycoprotein, functions as a receptor for hyaluronic acid. Our research group has previously shown that CD44 is a biomarker for the CD44^hi cells (tumor-initiating cells; TICs) in murine salivary gland tumors. However, little is known concerning the biological roles of CD44 in the tumorigenesis of pleomorphic adenoma. The present study is aimed to investigate the effects of CD44 on the proliferation, invasive capability, and apoptosis of TICs in vitro, as well as the tumorigenicity of TICs in vivo. The results demonstrated that knockdown of CD44 attenuated the malignant phenotype of TICs. Furthermore, in vivo xenograft studies indicated that CD44 knockdown inhibited tumorigenesis of pleomorphic adenoma. In addition, neither the CD44^low cells nor the CD44-modified CD44^low cells developed neo-tumors, which indicated that overexpression of CD44 did not enable the CD44^low cells to be transformed into TICs. Taken together, these data demonstrate that CD44 not only acts as a biomarker, but also functions as a key player in the tumor-initiating capacity of TICs. These results shed light on the pathogenesis of salivary gland tumors and provide a potential therapeutic target for treating pleomorphic adenoma.

Ion Channel Dysregulation in Head and Neck Cancers: Perspectives for Clinical Application

Head and neck cancers are a highly complex and heterogeneous group of malignancies that involve very diverse anatomical structures and distinct aetiological factors, treatments and clinical outcomes. Among them, head and neck squamous cell carcinomas (HNSCC) are predominant and the sixth most common cancer worldwide with still low survival rates. Omic technologies have unravelled the intricacies of tumour biology, harbouring a large diversity of genetic and molecular changes to drive the carcinogenesis process. Nonetheless, this remarkable heterogeneity of molecular alterations opens up an immense opportunity to discover novel biomarkers and develop molecular-targeted therapies. Increasing evidence demonstrates that dysregulation of ion channel expression and/or function is frequently and commonly observed in a variety of cancers from different origin. As a consequence, the concept of ion channels as potential membrane therapeutic targets and/or biomarkers for cancer diagnosis and prognosis has attracted growing attention. This chapter intends to comprehensively and critically review the current state-of-art ion channel dysregulation specifically focusing on head and neck cancers and to formulate the major challenges and research needs to translate this knowledge into clinical application. Based on current reported data, various voltage-gated potassium (K_v) channels (i.e. K_v3.4, K_v10.1 and K_v11.1) have been found frequently aberrantly expressed in HNSCC as well as precancerous lesions and are highlighted as clinically and biologically relevant features in both early stages of tumourigenesis and late stages of disease progression. More importantly, they also emerge as promising candidates as cancer risk markers, tumour markers and potential anti-proliferative and anti-metastatic targets for therapeutic interventions; however, the oncogenic properties seem to be independent of their ion-conducting function.

Epigenomic dysregulation-mediated alterations of key biological pathways and tumor immune evasion are hallmarks of gingivo-buccal oral cancer

BACKGROUND

Gingivo-buccal oral squamous cell carcinoma (OSCC-GB) is the most common cancer among men in India and is associated with high mortality. Although OSCC-GB is known to be quite different from tongue cancer in its genomic presentation and its clinical behavior, it is treated identically as tongue cancer. Predictive markers of prognosis and therapy that are specific to OSCC-GB are, therefore, required. Although genomic drivers of OSCC-GB have been identified by whole exome and whole genome sequencing, no epigenome-wide study has been conducted in OSCC-GB; our study has filled this gap, and has discovered and validated epigenomic hallmarks of gingivobuccal oral cancer.

METHODS

We have carried out integrative analysis of epigenomic (n = 87) and transcriptomic (n = 72) profiles of paired tumor-normal tissues collected from OSCC-GB patients from India. Genome-wide DNA methylation assays and RNA-sequencing were performed on high-throughput platforms (Illumina) using a half-sample of randomly selected patients to discover significantly differentially methylated probes (DMPs), which were validated on the remaining half-sample of patients.

RESULTS

About 200 genes showed significant inverse correlation between promoter methylation and expression, of which the most significant genes included genes that act as transcription factors and genes associated with other cancer types. Novel findings of this study include identification of (a) potential immunosuppressive effect in OSCC-GB due to significant promoter hypomethylation driven upregulation of CD274 and CD80, (b) significant dysregulation by epigenetic modification of DNMT3B (upregulation) and TET1 (downregulation); and (c) known drugs that can reverse the direction of dysregulation of gene expression caused by promoter methylation.

CONCLUSIONS

In OSCC-GB patients, there are significant alterations in expression of key genes that (a) regulate normal cell division by maintenance of balanced DNA methylation and transcription process, (b) maintain normal physiological signaling (PPAR, B cell receptor) and metabolism (arachidonic acid) pathways, and (c) provide immune protection against antigens, including tumor cells. These findings indicate novel therapeutic targets, including immunotherapeutic, for treatment of OSCC-GB.

Transcription factor early growth response-1 plays an oncogenic role in salivary gland pleomorphic adenoma

OBJECTIVES

Although abnormal expression of early growth response-1 (Egr1) has been revealed in various human solid tumors, the functions and potential mechanisms of Egr1 in the progression of salivary gland pleomorphic adenoma (SGPA) are not entirely understood.

RESULTS

An elevated expression of Egr1 was observed both in the human salivary gland pleomorphic adenoma tissues and tumor-initiating cell (TIC) cells, when compared with control group. By loss-of-function assay, the proliferation and invasion capacities of TICs were inhibited, while the cell apoptosis was promoted, which were further evidenced by the protein expression analysis of several key apoptosis-related regulators. Furthermore, TICs with Mithramycin A (an Egr1 inhibitor) treatment achieved the same effects of endogenous Egr1 knockdown.

CONCLUSIONS

All these data collectively suggest that Egr1 act as an oncogenic factor in salivary gland pleomorphic adenoma, which may be a potential target for the treatment of SGPA.

The Human Transient Receptor Potential Melastatin 2 Ion Channel Modulates ROS Through Nrf2

Transient receptor potential melastatin channel subfamily member 2 (TRPM2) has an essential role in protecting cell viability through modulation of oxidative stress. TRPM2 is highly expressed in cancer. When TRPM2 is inhibited, mitochondria are dysfunctional, ROS levels are increased, and cell viability is reduced. Here, the importance of NF-E2-related factor (Nrf2) in TRPM2-mediated suppression of oxidant stress was explored. In TRPM2 depleted cells, antioxidant cofactors glutathione, NADPH, and NADH were significantly reduced. Cytoplasmic and nuclear expression of Nrf2 and of IQGAP1, a modulator of Nrf2 stability regulated by intracellular calcium, were decreased. Antioxidant enzymes transcriptionally regulated by Nrf2 and involved in GSH, NADPH, and NADH generation were significantly lower including PRX1 and PRX3, GPX4, GSTP1, GCLC, and MTHFD2. The glutamine pathway leading to GSH production was suppressed, and ATP and GTP levels were impaired. Reconstitution with wild type TRPM2 or Nrf2, but not TRPM2 pore mutant E960D, rescued expression of enzymes downstream of Nrf2 and restored GSH and GTP. Cell viability, ROS, NADPH, NADH, and ATP levels were fully rescued by TRPM2 and partially by Nrf2. These data show that TRPM2 maintains cell survival following oxidative stress through modulation of antioxidant pathways and cofactors regulated by Nrf2.

The oncogenic roles of TRPM ion channels in cancer

Transient receptor potential (TRP) proteins are a diverse family of ion channels present in multiple types of tissues. They function as gatekeepers for responses to sensory stimuli including temperature, vision, taste, and pain through their activities in conducting ion fluxes. The TRPM (melastatin) subfamily consists of eight members (i.e., TRPM1-8), which collectively regulate fluxes of various types of cations such as K⁺ , Na⁺ , Ca²⁺ , and Mg²⁺ . Growing evidence in the past two decades indicates that TRPM ion channels, their isoforms, or long noncoding RNAs encoded within the locus may be oncogenes involved in the regulation of cancer cell growth, proliferation, autophagy, invasion, and epithelial-mesenchymal transition, and their significant association with poor clinical outcomes of cancer patients. In this review, we describe and discuss recent findings implicating TRPM channels in different malignancies, their functions, mechanisms, and signaling pathways involved in cancers, as well as summarizing their normal physiological functions and the availability of ion channel pharmacological inhibitors.

TRPM2 in Cancer

The TRP ion channel TRPM2 has an essential function in cell survival and protects the viability of a number of cell types after oxidative stress. It is highly expressed in many cancers including breast, prostate, and pancreatic cancer, melanoma, leukemia, and neuroblastoma, suggesting it promotes cancer cell survival. TRPM2 is activated by production of ADP-ribose (ADPR) following oxidative stress, which binds to the C-terminus of TRPM2, resulting in channel opening. In a number of cancers including neuroblastoma, TRPM2 has been shown to preserve viability and mechanisms have been identified. Activation of TRPM2 results in expression of transcription factors and kinases important in cell proliferation and survival including HIF-1/2α, CREB, nuclear factor (erythroid-derived 2)-related factor-2 (Nrf2), and Pyk2, and Src phosphorylation. Together, HIF-1/2α and CREB regulate expression of genes encoding proteins with roles in mitochondrial function including members of the electron transport complex involved in ATP production. These contribute to lower mitochondrial ROS production while expression of antioxidants regulated by HIF-1/2α, FOXO3a, CREB, and Nrf2 is maintained. CREB is also important in control of expression of key proteins involved in autophagy. When TRPM2-mediated calcium influx is inhibited, mitochondria are dysfunctional, cellular bioenergetics are reduced, production of ROS is increased, and autophagy and DNA repair are impaired, decreasing tumor growth and increasing chemotherapy sensitivity. Inhibition of TRPM2 expression or function results in decreased tumor proliferation and/or viability in many malignancies including breast, gastric, pancreatic, prostate, head and neck cancers, melanoma, neuroblastoma, and T-cell and acute myelogenous leukemia. However, in a small number of malignancies, activation of TRPM2 rather than inhibition has been reported to reduce tumor cell survival. Here, TRPM2-mediated Ca²⁺ signaling and mechanisms of regulation of cancer cell growth and survival are reviewed and controversies discussed. Evidence suggests that targeting TRPM2 may be a novel therapeutic approach in many cancers.

The human ion channel TRPM2 modulates neuroblastoma cell survival and mitochondrial function through Pyk2, CREB, and MCU activation

Transient receptor potential melastatin channel subfamily member 2 (TRPM2) has an essential function in cell survival and is highly expressed in many cancers. Inhibition of TRPM2 in neuroblastoma by depletion with CRISPR technology or expression of dominant negative TRPM2-S has been shown to significantly reduce cell viability. Here, the role of proline-rich tyrosine kinase 2 (Pyk2) in TRPM2 modulation of neuroblastoma viability was explored. In TRPM2-depleted cells, phosphorylation and expression of Pyk2 and cAMP-responsive element-binding protein (CREB), a downstream target, were significantly reduced after application of the chemotherapeutic agent doxorubicin. Overexpression of wild-type Pyk2 rescued cell viability. Reduction of Pyk2 expression with shRNA decreased cell viability and CREB phosphorylation and expression, demonstrating Pyk2 modulates CREB activation. TRPM2 depletion impaired phosphorylation of Src, an activator of Pyk2, and this may be a mechanism to reduce Pyk2 phosphorylation. TRPM2 inhibition was previously demonstrated to decrease mitochondrial function. Here, CREB, Pyk2, and phosphorylated Src were reduced in mitochondria of TRPM2-depleted cells, consistent with their role in modulating expression and activation of mitochondrial proteins. Phosphorylated Src and phosphorylated and total CREB were reduced in TRPM2-depleted nuclei. Expression and function of mitochondrial calcium uniporter (MCU), a target of phosphorylated Pyk2 and CREB, were significantly reduced. Wild-type TRPM2 but not Ca²⁺-impermeable mutant E960D reconstituted phosphorylation and expression of Pyk2 and CREB in TRPM2-depleted cells exposed to doxorubicin. Results demonstrate that TRPM2 expression protects the viability of neuroblastoma through Src, Pyk2, CREB, and MCU activation, which play key roles in maintaining mitochondrial function and cellular bioenergetics.

TRPM2 channel-mediated regulation of autophagy maintains mitochondrial function and promotes gastric cancer cell survival via the JNK-signaling pathway

A lack of effective treatment is one of the main factors contributing to gastric cancer-related death. Discovering effective targets and understanding their underlying anti-cancer mechanism are key to achieving the best response to treatment and to limiting side effects. Although recent studies have shown that the cation channel transient receptor potential melastatin-2 (TRPM2) is crucial for cancer cell survival, the exact mechanism remains unclear, limiting its therapeutic potential. Here, using molecular and functional assays, we investigated the role of TRPM2 in survival of gastric cancer cells. Our results indicated that TRPM2 knockdown in AGS and MKN-45 cells decreases cell proliferation and enhances apoptosis. We also observed that the TRPM2 knockdown impairs mitochondrial metabolism, indicated by a decrease in basal and maximal mitochondrial oxygen consumption rates and ATP production. These mitochondrial defects coincided with a decrease in autophagy and mitophagy, indicated by reduced levels of autophagy- and mitophagy-associated proteins (i.e. ATGs, LC3A/B II, and BNIP3). Moreover, we found that TRPM2 modulates autophagy through a c-Jun N-terminal kinase (JNK)-dependent and mechanistic target of rapamycin-independent pathway. We conclude that in the absence of TRPM2, down-regulation of the JNK-signaling pathway impairs autophagy, ultimately causing the accumulation of damaged mitochondria and death of gastric cancer cells. Of note, by inhibiting cell proliferation and promoting apoptosis, the TRPM2 down-regulation enhanced the efficacy of paclitaxel and doxorubicin in gastric cancer cells. Collectively, we provide compelling evidence that TRPM2 inhibition may benefit therapeutic approaches for managing gastric cancer.