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

Targeting Transient Receptor Potential Melastatin-2 (TRPM2) Enhances Therapeutic Efficacy of Third Generation EGFR Inhibitors against EGFR Mutant Lung Cancer

There is an urgent need to fully understand the biology of third generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs), particularly osimertinib, and to develop mechanism-driven strategies to manage their acquired resistance. Transient receptor potential melastatin-2 (TRPM2) functions as an important regulator of Ca2+ influx, but its role in mediating therapeutic efficacies of EGFR-TKIs and acquired resistance to EGFR-TKIs has been rarely studied. This study has demonstrated a previously undiscovered role of suppression of TRPM2 and subsequent inhibition of Ca2+ influx and induction of ROS and DNA damage in mediating apoptosis induction and the therapeutic efficacy of osimertinib against EGFR mutant NSCLC. The rebound elevation represents a key mechanism accounting for the emergence of acquired resistance to osimertinib and other third generation EGFR-TKIs. Accordingly, targeting TRPM2 is a potentially promising strategy for overcoming and preventing acquired resistance to osimertinib, warranting further study in this direction including the development of cancer therapy-optimized TRPM2 inhibitors.

YAP1 inhibits RSL3-induced castration-resistant prostate cancer cell ferroptosis by driving glutamine uptake and metabolism to GSH

High levels of YAP1 and ferroptosis activation in castration-resistant prostate cancer (CRPC) can inhibit CRPC progression and improve its sensitivity toward chemotherapeutics drugs. However, whether YAP1 regulates ferroptosis in CRPC cells and the underlying mechanisms are unknown. The protein levels of YAP1, SLC1A5, and GLS1 in benign prostatic hyperplasia (BPH), prostate cancer (PCa) that did not progress to CRPC, and CRPC tissue samples were evaluated using western blotting. In PC-3 and DU-145 cells, YAP1 overexpression vector, small-interfering RNA, specific inhibitor verteporfin, ferroptosis-inducer RSL3, SLC1A5-inhibitor V-9302, and GLS1-inhibitor CB-839 were used. Immunofluorescence, flow cytometry, dual-luciferase reporter gene, and related kits were used to investigate the effect of YAP1 on the ferroptosis activity in CRPC cells and its underlying mechanisms. YAP1 promoted extracellular glutamine uptake and subsequent production of glutamate and glutathione (GSH), and increases the GPX4 activity. For the activation of ferroptosis by RSL3, YAP1 decreased the levels of reactive oxygen species, malondialdehyde, and lipid peroxidation, and the proportion of dead cells. Mechanistically, YAP1 promoted the expression of SCL1A5 and GLS1 and further increased the GSH levels and GPX4 activity. Thus, inhibiting SLC1A5 or GLS1 activity could alleviate the antagonistic effect of YAP1 on the ferroptosis of RSL3-induced CRPC cells. In CRPC, the YAP1 level is high, which enters the nucleus and promotes the expressions of SLC1A5 and GLS1, thereby promoting cellular glutamine uptake and metabolism to generate glutamate and further synthesizing GSH, increasing GPX4 activity, improving cellular antioxidant capacity, and inhibiting cell death.

Targeting TRPs in autophagy regulation and human diseases

Transient receptor potential channels (TRPs) are widely recognized as a group of ion channels involved in various sensory perceptions, such as temperature, taste, pressure, and vision. While macroautophagy (hereafter referred to as autophagy) is primarily regulated by core machinery, the ion exchange mediated by TRPs between intracellular and extracellular compartments, as well as within organelles and the cytoplasm, plays a crucial role in autophagy regulation as an important signaling transduction mechanism. Moreover, certain TRPs can directly interact with autophagy regulatory proteins to participate in autophagy regulation. In this article, we provide an in-depth review of the current understanding of the regulatory mechanisms of autophagy, with a specific focus on TRPs. Furthermore, we highlight the potential prospects for drug development targeting TRPs in autophagy for the treatment of human diseases.

Research progress on the mechanism and signalling pathway of ferroptosis and its potential role in dermatosis research

Ferroptosis is a novel type of cell death that is dependent on lipid peroxidation and iron accumulation, which distinguishes it from other types of programmed cell death. Current research indicates a significant association between ferroptosis and various pathological conditions, including cancer, neurological disorders, and cardiovascular diseases, albeit with a relatively unexplored role in dermatological afflictions. This paper elaborates on the mechanisms and signalling pathways of ferroptosis, summarizing the recent studies on ferroptosis and its related factors in dermatosis. Our objective is to shed light on novel perspectives and therapeutic strategies for dermatosis, enhancing the understanding of this under-researched area through this comprehensive review.

Trpm2 deficiency in microglia attenuates neuroinflammation during epileptogenesis by upregulating autophagy via the AMPK/mTOR pathway

Epilepsy is one of the most common neurological disorders. Neuroinflammation involving the activation of microglia and astrocytes constitutes an important and common mechanism in epileptogenesis. Transient receptor potential melastatin 2 (TRPM2) is a calcium-permeable, non-selective cation channel that plays pathological roles in various inflammation-related diseases. Our previous study demonstrated that Trpm2 knockout exhibits therapeutic effects on pilocarpine-induced glial activation and neuroinflammation. However, whether TRPM2 in microglia and astrocytes plays a common pathogenic role in this process and the underlying molecular mechanisms remained undetermined. Here, we demonstrate a previously unknown role for microglial TRPM2 in epileptogenesis. Trpm2 knockout in microglia attenuated kainic acid (KA)-induced glial activation, inflammatory cytokines production and hippocampal paroxysmal discharges, whereas Trpm2 knockout in astrocytes exhibited no significant effects. Furthermore, we discovered that these therapeutic effects were mediated by upregulated autophagy via the adenosine monophosphate activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway in microglia. Thus, our findings highlight an important deleterious role of microglial TRPM2 in temporal lobe epilepsy.

Endoplasmic Reticulum Stress-Related Ten-Biomarker Risk Classifier for Survival Evaluation in Epithelial Ovarian Cancer and TRPM2: A Potential Therapeutic Target of Ovarian Cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignant tumor. Endoplasmic reticulum (ER) stress plays an important role in the malignant behaviors of several tumors. In this study, we established a risk classifier based on 10 differentially expressed genes related to ER stress to evaluate the prognosis of patients and help to develop novel medical decision-making for EOC cases. A total of 378 EOC cases with transcriptome data from the TCGA-OV public dataset were included. Cox regression analysis was used to establish a risk classifier based on 10 ER stress-related genes (ERGs). Then, through a variety of statistical methods, including survival analysis and receiver operating characteristic (ROC) methods, the prediction ability of the proposed classifier was tested and verified. Similar results were confirmed in the GEO cohort. In the immunoassay, the different subgroups showed different penetration levels of immune cells. Finally, we conducted loss-of-function experiments to silence TRPM2 in the human EOC cell line. We created a 10-ERG risk classifier that displays a powerful capability of survival evaluation for EOC cases, and TRPM2 could be a potential therapeutic target of ovarian cancer cells.

TRPM2: bridging calcium and ROS signaling pathways-implications for human diseases

TRPM2 is a versatile and essential signaling molecule that plays diverse roles in Ca2+ homeostasis and oxidative stress signaling, with implications in various diseases. Research evidence has shown that TRPM2 is a promising therapeutic target. However, the decision of whether to activate or inhibit TRPM2 function depends on the context and specific disease. A deeper understanding of the molecular mechanisms governing TRPM2 activation and regulation could pave the way for the development of innovative therapeutics targeting TRPM2 to treat a broad range of diseases. In this review, we examine the structural and biophysical details of TRPM2, its involvement in neurological and cardiovascular diseases, and its role in inflammation and immune system function. In addition, we provide a comprehensive overview of the current knowledge of TRPM2 signaling pathways in cancer, including its functions in bioenergetics, oxidant defense, autophagy, and response to anticancer drugs.

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-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.

The human ion channel TRPM2 modulates migration and invasion in neuroblastoma through regulation of integrin expression

Transient receptor potential channel TRPM2 is highly expressed in many cancers and involved in regulation of key physiological processes including mitochondrial function, bioenergetics, and oxidative stress. In Stage 4 non-MYCN amplified neuroblastoma patients, high TRPM2 expression is associated with worse outcome. Here, neuroblastoma cells with high TRPM2 expression demonstrated increased migration and invasion capability. RNA sequencing, RT-qPCR, and Western blotting demonstrated that the mechanism involved significantly greater expression of integrins α1, αv, β1, and β5 in cells with high TRPM2 expression. Transcription factors HIF-1α, E2F1, and FOXM1, which bind promoter/enhancer regions of these integrins, were increased in cells with high TRPM2 expression. Subcellular fractionation confirmed high levels of α1, αv, and β1 membrane localization and co-immunoprecipitation confirmed the presence of α1β1, αvβ1, and αvβ5 complexes. Inhibitors of α1β1, αvβ1, and αvβ5 complexes significantly reduced migration and invasion in cells highly expressing TRPM2, confirming their functional role. Increased pAkt^Ser473 and pERK^{Thr202/Tyr204}, which promote migration through mechanisms including integrin activation, were found in cells highly expressing TRPM2. TRPM2 promotes migration and invasion in neuroblastoma cells with high TRPM2 expression through modulation of integrins together with enhancing cell survival, negatively affecting patient outcome and providing rationale for TRPM2 inhibition in anti-neoplastic therapy.

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.

The human ion channel TRPM2 modulates cell survival in neuroblastoma through E2F1 and FOXM1

Transient receptor potential channel melastatin 2 (TRPM2) is highly expressed in cancer and has an essential function in preserving viability through maintenance of mitochondrial function and antioxidant response. Here, the role of TRPM2 in cell survival was examined in neuroblastoma cells with TRPM2 deletion with CRISPR technology. Viability was significantly decreased in TRPM2 knockout after doxorubicin treatment. RNA sequence analysis and RT-qPCR revealed reduced RNAs encoding master transcription regulators FOXM1 and E2F1/2 and downstream cell cycle targets including Cyclin B1, CDK1, PLK1, and CKS1. CHIP analysis demonstrated decreased FOXM1 binding to their promoters. Western blotting confirmed decreased expression, and increased expression of CDK inhibitor p21, a CKS1 target. In cells with TRPM2 deletion, cell cycle progression to S and G2/M phases was reduced after treatment with doxorubicin. RNA sequencing also identified decreased DNA repair proteins in cells with TRPM2 deletion after doxorubicin treatment, and DNA damage was increased. Wild type TRPM2, but not Ca²⁺-impermeable mutant E960D, restored live cell number and reconstituted expression of E2F1, FOXM1, and cell cycle/DNA repair proteins. FOXM1 expression alone restored viability. TRPM2 is a potential therapeutic target to reduce tumor proliferation and increase doxorubicin sensitivity through modulation of FOXM1, E2F1, and cell cycle/DNA repair proteins.

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.

A metal-free salalen ligand with anti-tumor and synergistic activity in resistant leukemia and solid tumor cells via mitochondrial pathway

PURPOSE

Since the discovery of the well-known cis-platin, transition metal complexes are highly recognized as cytostatic agents. However, toxic side effects of the metal ions present in the complexes may pose significant problems for their future development. Therefore, we investigated the metal-free salalen ligand WQF 044.

METHODS

DNA fragmentations in leukemia (Nalm6) and solid tumor cells (BJAB, MelHO, MCF-7, RM82) proved the apoptotic effects of WQF 044, its overcoming of resistances and the cellular pathways that are affected by the substance. The apoptotic mechanisms finding were supported by western blot analysis, measurement of the mitochondrial membrane potential and polymerase chain reactions.

RESULTS

A complex intervention in the mitochondrial pathway of apoptosis with a Bcl-2 and caspase dependence was observed. Additionally, a wide range of tumors were affected by the ligand in a low micromolar range in-vitro. The compound overcame multidrug resistances in P-gp over-expressed acute lymphoblastic leukemia and CD95-downregulated Ewing's sarcoma cells. Quite remarkable synergistic effects with vincristine were observed in Burkitt-like lymphoma cells.

CONCLUSION

The investigation of a metal-free salalen ligand as a potential anti-cancer drug revealed in promising results for a future clinical use.

Compensatory expression of NRF2-dependent antioxidant genes is required to overcome the lethal effects of Kv11.1 activation in breast cancer cells and PDOs

Potassium channels are important regulators of cellular homeostasis and targeting these proteins pharmacologically is unveiling important mechanisms in cancer cell biology. Here we demonstrate that pharmacological stimulation of the Kv11.1 potassium channel activity results in mitochondrial reactive oxygen species (ROS) production and fragmentation in breast cancer cell lines and patient-derived organoids independent of breast cancer subtype. mRNA expression profiling revealed that Kv11.1 activity significantly altered expression of genes controlling the production of ROS and endoplasmic-reticulum (ER) stress. Characterization of the transcriptional signature of breast cancer cells treated with Kv11.1 potassium channel activators strikingly revealed an adaptive response to the potentially lethal augmentation of ROS by increasing Nrf2-dependent transcription of antioxidant genes. Nrf2 in this context was shown to promote survival in breast cancer, whereas knockdown of Nrf2 lead to Kv11.1-induced cell death. In conclusion, we found that the Kv11.1 channel activity promotes oxidative stress in breast cancer cells and that suppression of the Nrf2-mediated anti-oxidant survival mechanism strongly sensitized breast cancer cells to a lethal effect of pharmacological activation of Kv11.1.

Systematic Understanding of Pathophysiological Mechanisms of Oxidative Stress-Related Conditions-Diabetes Mellitus, Cardiovascular Diseases, and Ischemia-Reperfusion Injury

Reactive oxygen species (ROS) plays a role in intracellular signal transduction under physiological conditions while also playing an essential role in diseases such as hypertension, ischemic heart disease, and diabetes, as well as in the process of aging. The influence of ROS has some influence on the frequent occurrence of cardiovascular diseases (CVD) in diabetic patients. In this review, we considered the pathophysiological relationship between diabetes and CVD from the perspective of ROS. In addition, considering organ damage due to ROS elevation during ischemia-reperfusion, we discussed heart and lung injuries. Furthermore, we have focused on the transient receptor potential (TRP) channels and L-type calcium channels as molecular targets for ROS in ROS-induced tissue damages and have discussed about the pathophysiological mechanism of the injury.

The fate of melanocyte: Mechanisms of cell death in vitiligo

Loss of melanocytes (MCs) is the most notable feature of vitiligo. Hence, it is critical to clarify the mechanisms of MC destruction in vitiligo. Apoptosis is most widely studied cell death pathways in vitiligo. In addition, the other two forms of cell death, conventional necrosis and autophagy seem to be involved in the death of vitiligo MCs under certain situations. Moreover, new types of regulated cell death including necroptosis, pyroptosis, and ferroptosis may also participate in the pathogenesis of vitiligo. Anoikis is likely to be connected with the death of detached MCs, which is provoked specifically by loss of anchorage. Primary phagocytosis, later called phagoptosis can execute death of viable cells, probably partly responsible for the loss of MCs in vitiligo. In this review, we aim to summarize the latest insights into various forms of MC death in vitiligo and discuss the corresponding mechanisms.

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.

Ca2+ Fluxes and Cancer

Ca²⁺ ions are key second messengers in both excitable and non-excitable cells. Owing to the rather pleiotropic nature of Ca²⁺ transporters and other Ca²⁺-binding proteins, however, Ca²⁺ signaling has attracted limited attention as a potential target of anticancer therapy. Here, we discuss cancer-associated alterations of Ca²⁺ fluxes at specific organelles as we identify novel candidates for the development of drugs that selectively target Ca²⁺ signaling in malignant cells.

The NRF2/KEAP1 Axis in the Regulation of Tumor Metabolism: Mechanisms and Therapeutic Perspectives

The NRF2/KEAP1 pathway is a fundamental signaling cascade that controls multiple cytoprotective responses through the induction of a complex transcriptional program that ultimately renders cancer cells resistant to oxidative, metabolic and therapeutic stress. Interestingly, accumulating evidence in recent years has indicated that metabolic reprogramming is closely interrelated with the regulation of redox homeostasis, suggesting that the disruption of NRF2 signaling might represent a valid therapeutic strategy against a variety of solid and hematologic cancers. These aspects will be the focus of the present review.