Xyloketal B suppresses glioblastoma cell proliferation and migration in vitro through inhibiting TRPM7-regulated PI3K/Akt and MEK/ERK signaling pathways

Roles of TRPM channels in glioma

Gliomas are the most common type of primary brain tumor. Despite advances in treatment, it remains one of the most aggressive and deadly tumor of the central nervous system (CNS). Gliomas are characterized by high malignancy, heterogeneity, invasiveness, and high resistance to radiotherapy and chemotherapy. It is urgent to find potential new molecular targets for glioma. The TRPM channels consist of TRPM1-TPRM8 and play a role in many cellular functions, including proliferation, migration, invasion, angiogenesis, etc. More and more studies have shown that TRPM channels can be used as new therapeutic targets for glioma. In this review, we first introduce the structure, activation patterns, and physiological functions of TRPM channels. Additionally, the pathological mechanism of glioma mediated by TRPM2, 3, 7, and 8 and the related signaling pathways are described. Finally, we discuss the therapeutic potential of targeting TRPM for glioma.

Prospects of marine-derived compounds as potential therapeutic agents for glioma

CONTEXT

Glioma, the most common primary malignant brain tumour, is a grave health concern associated with high morbidity and mortality. Current treatments, while effective to some extent, are often hindered by factors such as the blood-brain barrier and tumour microenvironment. This underscores the pressing need for exploring new pharmacologically active anti-glioma compounds.

METHODS

This review synthesizes information from major databases, including Chemical Abstracts, Medicinal and Aromatic Plants Abstracts, ScienceDirect, SciFinder, Google Scholar, Scopus, PubMed, Springer Link and relevant books. Publications were selected without date restrictions, using terms such as 'Hymenocrater spp.,' 'phytochemical,' 'pharmacological,' 'extract,' 'essential oil' and 'traditional uses.' General web searches using Google and Yahoo were also performed. Articles related to agriculture, ecology, synthetic work or published in languages other than English or Chinese were excluded.

RESULTS

The marine environment has been identified as a rich source of diverse natural products with potent antitumour properties.

CONCLUSIONS

This paper not only provides a comprehensive review of marine-derived compounds but also unveils their potential in treating glioblastoma multiforme (GBM) based on functional classifications. It encapsulates the latest research progress on the regulatory biological functions and mechanisms of these marine substances in GBM, offering invaluable insights for the development of new glioma treatments.

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.

The Role of TRPM7 in Oncogenesis

This review summarizes the current understanding of the role of transient receptor potential melastatin-subfamily member 7 (TRPM7) channels in the pathophysiology of neoplastic diseases. The TRPM family represents the largest and most diverse group in the TRP superfamily. Its subtypes are expressed in virtually all human organs playing a central role in (patho)physiological events. The TRPM7 protein (along with TRPM2 and TRPM6) is unique in that it has kinase activity in addition to the channel function. Numerous studies demonstrate the role of TRPM7 chanzyme in tumorigenesis and in other tumor hallmarks such as proliferation, migration, invasion and metastasis. Here we provide an up-to-date overview about the possible role of TRMP7 in a broad range of malignancies such as tumors of the nervous system, head and neck cancers, malignant neoplasms of the upper gastrointestinal tract, colorectal carcinoma, lung cancer, neoplasms of the urinary system, breast cancer, malignant tumors of the female reproductive organs, prostate cancer and other neoplastic pathologies. Experimental data show that the increased expression and/or function of TRPM7 are observed in most malignant tumor types. Thus, TRPM7 chanzyme may be a promising target in tumor therapy.

SIRT3 enhances the protective effect of Xyloketal B on seizure-induced brain injury by regulating AMPK/mTOR signaling-mediated autophagy

Brain damage in children due to seizures is irreversible and has been a major public health concern. The herbal monomer Xyloketal B (Xyl-B) can be used as a neuroprotective drug because of its antioxidant, antiapoptotic, and anti-inflammatory effects but with few adverse effects. In this article, we constructed a rat developmental convulsion model and a primary hippocampal neuronal cell convulsion model, through which we studied hippocampal neuronal morphology and neuronal apoptosis using H&E staining and TUNEL staining, respectively. Moreover, we measured TNF-α, IL-6, and IL-1β inflammatory factor levels using ELISA, MDA, and SOD kits. The expression of SIRT3 in hippocampal tissues was determined by qPCR and Western blotting. The expression of autophagy-related proteins such as LC3, p62, and Beclin-1 was evaluated by Western blotting or immunohistochemistry. The role of SIRT3 and autophagic activity with Xyl-B in convulsive seizure-induced brain injury was investigated by knocking down SIRT3 expression levels. Our results showed that Xyl-B plays a neuroprotective role in convulsive seizure-induced brain injury by increasing SIRT3 expression and activating the autophagy pathway. The regulatory role of SIRT3 in the autophagy pathway with Xyl-B treatment was explored by knocking down SIRT3 expression and inhibiting autophagy. Our results revealed that SIRT3 enhances the protective effect of Xyl-B against postconvulsive brain injury by regulating AMPK/mTOR signaling-mediated autophagy.

Shikimate-Derived Meroterpenoids from the Ascidian-Derived Fungus Amphichorda felina SYSU-MS7908 and Their Anti-Glioma Activity

Glioma is a clinically heterogeneous type of brain tumor with a poor prognosis. Current treatment approaches have limited effectiveness in treating glioma, highlighting the need for novel drugs. One approach is to explore marine natural products for their therapeutic potential. In this study, we isolated nine shikimate-derived diisoprenyl-cyclohexene/ane-type meroterpenoids (1-9), including four new ones, amphicordins A-D (1-4) from the ascidian-derived fungus Amphichorda felina SYSU-MS7908, and further semisynthesized four derivatives (10-13). Their structures were extensively characterized using 1D and 2D NMR, modified Mosher's method, HR-ESIMS, NMR and ECD calculations, and X-ray crystallography. Notably, amphicordin C (3) possesses a unique benzo[g]chromene (6/6/6) skeleton in this meroterpenoid family. In an anti-glioma assay, oxirapentyn A (7) effectively inhibited the proliferation, migration, and invasion of glioma cells and induced their apoptosis. Furthermore, an in silico analysis suggested that oxirapentyn A has the potential to penetrate the blood-brain barrier. These findings highlight the potential of oxirapentyn A as a candidate for the development of novel anti-glioma drugs.

Roles of TRPM7 in ovarian cancer

Ovarian cancer stands as the prevailing gynecologic malignancy, afflicting over 313,959 individuals annually worldwide, accompanied by more than 207,252 fatalities. Perturbations in calcium signaling contribute significantly to the pathogenesis of numerous cancers, including ovarian cancer, wherein alterations in calcium transporter expression have been reported. Overexpression of TRPM7, a prominent calcium transporter, has been linked to adverse prognostic outcomes in various cancer types. The focus of this comprehensive review centers around delineating the oncogenic role of TRPM7 in cancer development and exploring its therapeutic potential as a target in combating this disease. Notably, TRPM7 fosters cancer invasion, metastasis, and uncontrolled cell proliferation, thereby perpetuating the expansion and reinforcement of these malignant entities. Furthermore, this review takes ovarian cancer as an example and summarizes the "dual-mode" regulatory role of TRPM7 in cancer. Within the domain of ovarian cancer, TRPM7 assumes the role of a harsh tyrant, firmly controlling the calcium ion signaling pathway and metabolic reprogramming pathways.

TRPM7 kinase mediates hypomagnesemia-induced seizure-related death

Hypomagnesemia (HypoMg) can cause seizures and death, but the mechanism is unknown. Transient receptor potential cation channel subfamily M 7 (TRPM7) is a Mg transporter with both channel and kinase function. In this study, we focused on the kinase role of TRPM7 in HypoMg-induced seizures and death. Wild type C57BL/6J mice and transgenic mice with a global homozygous mutation in the TRPM7 kinase domain (TRPM7^K1646R, with no kinase function) were fed with control diet or a HypoMg diet. After 6 weeks of HypoMg diet, mice had significantly decreased serum Mg, elevated brain TRPM7, and a significant rate of death, with females being most susceptible. Deaths were immediately preceded by seizure events. TRPM7^K1646R mice showed resistance to seizure-induced death. HypoMg-induced brain inflammation and oxidative stress were suppressed by TRPM7^K1646R. Compared to their male counterparts, HypoMg female mice had higher levels of inflammation and oxidative stress in the hippocampus. We concluded that TRPM7 kinase function contributes seizure-induced deaths in HypoMg mice and that inhibiting the kinase reduced inflammation and oxidative stress.

Chemoenzymatic Synthesis of (+)-Xyloketal B

Xyloketal B is a pentacyclic fungal marine natural product that has shown potential for the treatment of diseases such as Alzheimer's disease and atherosclerosis. Herein, we describe the first asymmetric synthesis of this natural product, which relies on a chemoenzymatic strategy. This approach leverages a biocatalytic benzylic hydroxylation to access to an ortho-quinone methide intermediate which is captured in a [4 + 2] cycloaddition to stereoselectively yield a key cyclic ketal intermediate enroute to (+)-xyloketal B. The relative configuration of this intermediate was rapidly confirmed as the desired stereoisomer using MicroED. To complete the synthesis, a second ortho-quinone methide was accessed through a reductive approach, ultimately leading to the stereoselective synthesis of (+)-xyloketal B.

Progress in targeting PTEN/PI3K/Akt axis in glioblastoma therapy: Revisiting molecular interactions

Glioblastoma (GBM) is one of the most malignant cancers of central nervous system and due to its sensitive location, surgical resection has high risk and therefore, chemotherapy and radiotherapy are utilized for its treatment. However, chemoresistance and radio-resistance are other problems in GBM treatment. Hence, new therapies based on genes are recommended for treatment of GBM. PTEN is a tumor-suppressor operator in cancer that inhibits PI3K/Akt/mTOR axis in diminishing growth, metastasis and drug resistance. In the current review, the function of PTEN/PI3K/Akt axis in GBM progression is evaluated. Mutation or depletion of PTEN leads to increase in GBM progression. Low expression level of PTEN mediates poor prognosis in GBM and by increasing proliferation and invasion, promotes malignancy of tumor cells. Moreover, loss of PTEN signaling can result in therapy resistance in GBM. Activation of PTEN signaling impairs GBM metabolism via glycolysis inhibition. In contrast to PTEN, PI3K/Akt signaling has oncogenic function and during tumor progression, expression level of PI3K/Akt enhances. PI3K/Akt signaling shows positive association with oncogenic pathways and its expression similar to PTEN signaling, is regulated by non-coding RNAs. PTEN upregulation and PI3K/Akt signaling inhibition by anti-cancer agents can be beneficial in interfering GBM progression. This review emphasizes on the signaling networks related to PTEN/PI3K/Akt and provides new insights for targeting this axis in effective GBM treatment.

A pan-cancer-bioinformatic-based literature review of TRPM7 in cancers

TRPM7, a divalent cation-selective channel with kinase domains, has been widely reported to potentially affect cancers. In this study, we conducted multiple bioinformatic analyses based on open databases and reviewed articles that provided evidence for the effects of TRPM7 on cancers. The purposes of this paper are 1) to provide a pan-cancer overview of TRPM7 in cancers; 2) to summarize evidence of TRPM7 effects on cancers; 3) to identify potential future studies of TRPM7 in cancer. Bioinformatics analysis revealed that no cancer-related TRPM7 mutation was found. TRPM7 is aberrantly expressed in most cancer types but the cancer-noncancer expression pattern varies across cancer types. TRPM7 was not associated with survival, TMB, or cancer stemness in most cancer types. TRPM7 affected drug sensitivity and tumor immunity in some cancer types. The in vitro evidence, preclinical in vivo evidence, and clinical evidence for TRPM7 effects on cancers as well as TRPM7 kinase substrate and TRPM7-targeting drugs associated with cancers were summarized to facilitate comparison. We matched the bioinformatics evidence to literature evidence, thereby unveiling potential avenues for future investigation of TRPM7 in cancers. We believe that this paper will help orient research toward important and relevant aspects of the role of TRPM7 in cancers.

Knockdown of TRPM7 attenuates apoptosis and inflammation in neonatal necrotizing enterocolitis model cell IEC-6 via modulating TLR4/NF-κB and MEK/ERK pathways

OBJECTIVES

Neonatal necrotizing enterocolitis (NEC) is the most common gastrointestinal critical illness in neonatal infants. TRPM7 reportedly plays a role in human inflammatory bowel disease (IBD) and colorectal cancer, but the role of TRPM7 in the pathogenesis of NEC remains vague.

MATERIALS AND METHODS

The expression of TRPM7 was determined in intestinal tissues of NEC patients and lipopolysaccharide (LPS)-induced IEC-6 cells. Subsequently, a loss-of-function assay was performed to assess the effects of TRPM7 on cell apoptosis and inflammatory response in IEC-6 cells after LPS induction. Furthermore, the modulation of TRPM7 on TLR4/NF-κB and MEK/ERK signaling pathways was validated.

RESULTS

The expression of TRPM7 was higher in the intestinal tissues of NEC patients compared with the normal human intestinal tissues. Moreover, the expression level of TRPM7 was elevated in LPS stimulation IEC-6 cells. Knockdown of TRPM7 enhanced cell viability and suppressed apoptosis, accompanied by the decreased Bax/Bcl-1 ratio and cleaved-caspase3 expression in LPS-induced IEC-6 cells. Additionally, TRPM7 silencing attenuated LPS-induced expressions and secretions of proinflammatory cytokines. Mechanistically, TRPM7 knockdown inhibited the TLR4/NF-κB activation, while enhancing the MEK/ERK activation in LPS-treated IEC-6 cells. Overexpression of TLR4 or inhibition of MEK attenuated the inhibitory effects of TRPM7 knockdown on LPS-induced apoptosis and inflammation in IEC-6 cells.

CONCLUSION

Knockdown of TRPM7 attenuated LPS-induced IEC-6 cell apoptosis and inflammation by modulating TLR4/NF-κB and MEK/ERK pathways.

Role of TRPM2 in brain tumours and potential as a drug target

Ion channels are ubiquitously expressed in almost all living cells, and are the third-largest category of drug targets, following enzymes and receptors. The transient receptor potential melastatin (TRPM) subfamily of ion channels are important to cell function and survival. Studies have shown upregulation of the TRPM family of ion channels in various brain tumours. Gliomas are the most prevalent form of primary malignant brain tumours with no effective treatment; thus, drug development is eagerly needed. TRPM2 is an essential ion channel for cell function and has important roles in oxidative stress and inflammation. In response to oxidative stress, ADP-ribose (ADPR) is produced, and in turn activates TRPM2 by binding to the NUDT9-H domain on the C-terminal. TRPM2 has been implicated in various cancers and is significantly upregulated in brain tumours. This article reviews the current understanding of TRPM2 in the context of brain tumours and overviews the effects of potential drug therapies targeting TRPM2 including hydrogen peroxide (H₂O₂), curcumin, docetaxel and selenium, paclitaxel and resveratrol, and botulinum toxin. It is long withstanding knowledge that gliomas are difficult to treat effectively, therefore investigating TRPM2 as a potential therapeutic target for brain tumours may be of considerable interest in the fields of ion channels and pharmacology.

Antiplatelet and Antithrombotic Effects of Isaridin E Isolated from the Marine-Derived Fungus via Downregulating the PI3K/Akt Signaling Pathway

Isaridin E, a cyclodepsipeptide isolated from the marine-derived fungus Amphichorda felina (syn. Beauveria felina) SYSU-MS7908, has been demonstrated to possess anti-inflammatory and insecticidal activities. Here, we first found that isaridin E concentration-dependently inhibited ADP-induced platelet aggregation, activation, and secretion in vitro, but did not affect collagen- or thrombin-induced platelet aggregation. Furthermore, isaridin E dose-dependently reduced thrombosis formation in an FeCl3-induced mouse carotid model without increasing the bleeding time. Mechanistically, isaridin E significantly decreased the ADP-mediated phosphorylation of PI3K and Akt. In conclusion, these results suggest that isaridin E exerts potent antithrombotic effects in vivo without increasing the risk of bleeding, which may be due to its important role in inhibiting ADP-induced platelet activation, secretion and aggregation via the PI3K/Akt pathways.

Modulators of TRPM7 and its potential as a drug target for brain tumours

TRPM7 is a non-selective divalent cation channel with an alpha-kinase domain. Corresponding with its broad expression, TRPM7 has a role in a wide range of cell functions, including proliferation, migration, and survival. Growing evidence shows that TRPM7 is also aberrantly expressed in various cancers, including brain cancers. Because ion channels have widespread tissue distribution and result in extensive physiological consequences when dysfunctional, these proteins can be compelling drug targets. In fact, ion channels comprise the third-largest drug target type, following enzymes and receptors. Literature has shown that suppression of TRPM7 results in inhibition of migration, invasion, and proliferation in several human brain tumours. Therefore, TRPM7 presents a potential target for therapeutic brain tumour interventions. This article reviews current literature on TRPM7 as a potential drug target in the context of brain tumours and provides an overview of various selective and non-selective modulators of the channel relevant to pharmacology, oncology, and ion channel function.

Downregulation of Williams syndrome transcription factor (WSTF) suppresses glioblastoma cell growth and invasion by inhibiting PI3K/AKT signal pathway

Williams syndrome transcription factor (WSTF) participates in diverse cellular processes, including tumor cell proliferation and migration. However, the function of WSTF in glioblastoma (GBM) remains unknown. Data from the Gene Expression Profiling Interactive Analysis (GEPIA) and The Cancer Genome Atlas (TCGA) datasets showed that WSTF was upregulated in GBM tissues. Moreover, WSTF was also increased in the GBM cells. pcDNA-mediated over-expression of WSTF contributed to cell proliferation and invasion of GBM cells, while GBM cell proliferation and invasion were suppressed by shRNA-mediated silencing of WSTF. Additionally, GBM cell apoptosis was reduced by over-expression of WSTF accompanied by decrease in Bax and cleaved caspase-3, while promoted by silencing of WSTF with increase in Bax and cleaved caspase-3. Protein expression of AKT phosphorylation was enhanced by WSTF over-expression while reduced by WSTF silencing. Inhibitor of phosphatidylinositol 3 kinase attenuated WSTF over-expression-induced increase in GBM cell proliferation and invasion. In conclusion, WSTF contributed to GBM cell growth and invasion through activation of PI3K/AKT pathway.

Secondary metabolites from mangrove-associated fungi: source, chemistry and bioactivities

Covering 1989 to 2020The mangrove forests are a complex ecosystem occurring at tropical and subtropical intertidal estuarine zones and nourish a diverse group of microorganisms including fungi, actinomycetes, bacteria, cyanobacteria, algae, and protozoa. Among the mangrove microbial community, mangrove associated fungi, as the second-largest ecological group of the marine fungi, not only play an essential role in creating and maintaining this biosphere but also represent a rich source of structurally unique and diverse bioactive secondary metabolites, attracting significant attention of organic chemists and pharmacologists. This review summarizes the discovery relating to the source and characteristics of metabolic products isolated from mangrove-associated fungi over the past thirty years (1989-2020). Its emphasis included 1387 new metabolites from 451 papers, focusing on bioactivity and the unique chemical diversity of these natural products.

Xyloketal B: A marine compound with medicinal potential

In recent decades, technological advantages have allowed scientists to isolate medicinal compounds from marine organisms that exhibit unique structure and bioactivity. The mangrove fungus Xylaria sp. from the South China Sea is rich in metabolites and produces a potent therapeutic compound, xyloketal B. Since its isolation in 2001, xyloketal B has been extensively studied in a wide variety of cell types and in vitro and in vivo disease models. Xyloketal B and its derivatives exhibit cytoprotective effects in cardiovascular and neurodegenerative diseases by reducing oxidative stress, regulating the apoptosis pathway, maintaining ionic balance, mitigating inflammatory responses, and preventing protein aggregation. Xyloketal B has also shown to alleviate lipid accumulation in a non-alcoholic fatty liver disease model. Moreover, xyloketal B treatment induces glioblastoma cell death. This review summarizes our current understanding of xyloketal B in various disease models.

Bioactive Compounds with Antiglioma Activity from Marine Species

The search for new chemical compounds with antitumor pharmacological activity is a necessary process for creating more effective drugs for each specific malignancy type. This review presents the outcomes of screening studies of natural compounds with high anti-glioma activity. Despite significant advances in cancer therapy, there are still some tumors currently considered completely incurable including brain gliomas. This review covers the main problems of the glioma chemotherapy including drug resistance, side effects of common anti-glioma drugs, and genetic diversity of brain tumors. The main emphasis is made on the characterization of natural compounds isolated from marine organisms because taxonomic diversity of organisms in seawaters significantly exceeds that of terrestrial species. Thus, we should expect greater chemical diversity of marine compounds and greater likelihood of finding effective molecules with antiglioma activity. The review covers at least 15 classes of organic compounds with their chemical formulas provided as well as semi-inhibitory concentrations, mechanisms of action, and pharmacokinetic profiles. In conclusion, the analysis of the taxonomic diversity of marine species containing bioactives with antiglioma activity is performed noting cytotoxicity indicators and to the tumor cells in comparison with similar indicators of antitumor agents approved for clinical use as antiglioblastoma chemotherapeutics.

Role of TRPM7 kinase in cancer

Cancer is the second leading cause of death worldwide and accounted for an estimated 9.6 million deaths, or 1 in 6 deaths, in 2018. Despite recent advances in cancer prevention, diagnosis, and treatment strategies, the burden of this disease continues to grow with each year, with dire physical, emotional, and economic consequences for all levels of society. Classic characteristics of cancer include rapid, uncontrolled cell proliferation and spread of cancerous cells to other parts of the body, a process known as metastasis. Transient receptor potential melastatin 7 (TRPM7), a Ca²⁺- and Mg²⁺-permeable nonselective divalent cation channel defined by the atypical presence of an α-kinase within its C-terminal domain, has been implicated, due to its modulation of Ca²⁺ and Mg²⁺ influx, in a wide variety of physiological and pathological processes, including cancer. TRPM7 is overexpressed in several cancer types and has been shown to variably increase cellular proliferation, migration, and invasion of tumour cells. However, the relative contribution of TRPM7 kinase domain activity to cancer as opposed to ion flux through its channel pore remains an area of active discovery. In this review, we describe the specific role of the TRPM7 kinase domain in cancer processes as well as mechanisms of regulation and inhibition of the kinase domain.

Protective effect of inhibiting TRPM7 expression on hypoxia post-treatment H9C2 cardiomyocytes

BACKGROUND

Transient receptor potential channel 7 (TRPM7) plays an important role in maintaining intracellular ion concentration and osmotic pressure.

OBJECTIVE

The purpose of this study was to investigate the role and mechanism of inhibiting the expression of TRPM7 in the treatment of distal myocardial ischemia.

METHODS

H9C2 cells were treated with hypoxia post-treatment and reperfusion, respectively, detect the expression of HIF-1α and TRPM7, the concentration of Ca2+ and the degree of apoptosis in the H9C2 cells. The relevant miRNAs targeting TRPM7 were searched, the TRPM7 interference vectors were constructed, and the interference of different interference vectors on TRPM7 in H9C2 cells was detected.

RESULTS

The results showed that hypoxia post-treatment treatment would lead to increased expression of miR-22-3p which directly targeting TRPM7, decreased expression of TRPM7, increased expression of HIF-α and increased intracellular Ca2+ concentration. While reperfusion can increase the expression of HIF-1α and TRPM7 in H9C2 cells and increase the degree of apoptosis.

CONCLUSION

Knockdown of TRPM7 can significantly reduce reperfusion injury in H9C2 cells, reduce the degree of apoptosis, and the TRPM7 interference vector can inhibit the expression of TRPM7 and have a certain protective effect on the reperfusion injury of H9C2 cells.

Waixenicin A, a marine-derived TRPM7 inhibitor: a promising CNS drug lead

Ion channels are the third largest class of targets for therapeutic drugs. The pharmacology of ion channels is an important research area for identifying new treatment options for human diseases. The past decade or so has seen increasing interest in an ion channel protein belonging to the transient receptor potential (TRP) family, namely the melastatin subfamily member 7 (TRPM7), as an emerging drug target. TRPM7 is a bifunctional protein with a magnesium and calcium-conducting divalent ion channel fused with an active kinase domain. TRPM7 is ubiquitously expressed in human tissues, including the brain, and regulates various cell biology processes such as magnesium and calcium homeostasis, cell growth and proliferation, and embryonic development. TRPM7 provides a link between cellular metabolic status and intracellular calcium homeostasis in neurons due to TRPM7's unique sensitivity to fluctuating intracellular Mg·ATP levels. Thus, the protein plays a key role in ischemic and hypoxic neuronal cell death and brain injury, and is one of the key nonglutamate mechanisms in cerebral ischemia and stroke. Currently, the most potent and specific TRPM7 inhibitor is waixenicin A, a xenicane diterpenoid from the Hawaiian soft coral Sarcothelia edmondsoni. Using waixenicin A as a pharmacological tool, we demonstrated that TRPM7 is involved in promoting neurite outgrowth in vitro. Most recently, we found that waixenicin A reduced hypoxic-ischemic brain injury and preserved long-term behavioral outcomes in mouse neonates. We here suggest that TRPM7 is an emerging drug target for CNS diseases and disorders, and waixenicin A is a viable drug lead for these disorders.

Inhibition of TRPM7 with waixenicin A reduces glioblastoma cellular functions

Glioblastoma (GBM) is the most common malignant primary brain tumour originating in the CNS. Median patient survival is <15 months with standard treatment which consists of surgery alongside radiation therapy and temozolomide chemotherapy. However, because of the aggressive nature of GBM, and the significant toxicity of these adjuvant therapies, long-term therapeutic effects are unsatisfactory. Thus, there is urgency to identify new drug targets for GBM. Recent evidence shows that the transient receptor potential melastatin 7 (TRPM7) cation channel is aberrantly upregulated in GBM and its inhibition leads to reduction of GBM cellular functions. This suggests that TRPM7 may be a potential drug target for GBM treatment. In this study, we assessed the effects of the specific TRPM7 antagonist waixenicin A on human GBM cell lines U87 or U251 both in vitro and in vivo. First, we demonstrated in vitro that application of waixenicin A reduced TRPM7 protein expression and inhibited the TRPM7-like currents in GBM cells. We also observed reduction of GBM cell viability, migration, and invasion. Using an intracranial xenograft GBM mouse model, we showed that with treatment of waixenicin A, there was increased cleaved caspase 3 activity, alongside reduction in Ki-67, cofilin, and Akt activity in vivo. Together, these data demonstrate higher GBM cell apoptosis, and lower proliferation, migration, invasion and survivability following treatment with waixenicin A.

Protein kinases as targets for developing anticancer agents from marine organisms

Protein kinases play a fundamental role in the intracellular transduction because of their ability to phosphorylate plethora of proteins. Over the past three decades, numerous protein kinase inhibitors have been identified and are being used clinically successfully. The biodiversity of marine organisms provides a rich source for the discovery and development of novel anticancer agents in the treatment of human malignancies and a lot of bioactive ingredients from marine organisms display anticancer effects by affecting the protein kinases-mediated pathways. In the present mini-review, anticancer compounds from marine source were reviewed and discussed in context of their targeted pathways associated with protein kinases and the progress of these compounds as anticancer agents in recent five years were emphasized. The molecular entities and their modes of actions were presented. We focused on protein kinases-mediated signaling pathways including PI3K/Akt/mTOR, p38 MAPK, and EGFR. The marine compounds targeting special pathways of protein kinases were highlighted. We have also discussed the existing challenges and prospects related to design and development of novel protein kinase inhibitors from marine sources.

Bioactivity of Marine Natural Product Xyloketals

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Oceans can play a major role in supplying life-saving medicines in the world in future. Although considerable progress has been made in finding new medicines from marine sources, large efforts are still necessary to examine such molecules for clinical applications. Xyloketals are an important group of natural products with various powerful and prominent bioactivities such as inhibition of acetylcholine esterase, antioxidant activity, inhibition of L-calcium channels, radicalscavenging behavior, suppression of cell proliferation, reduction of neonatal hypoxic-ischemic brain injury, etc. This review describes the isolation and structural characterization of all xyloketal natural products giving major emphasis on their bioactivity.

Marine compounds targeting the PI3K/Akt signaling pathway in cancer therapy

Cancer is a disease characterized by overproliferation, including that due to transformation, apoptosis disorders, proliferation, invasion, angiogenesis and metastasis, and is one of the deadliest diseases. Currently, conservative chemotherapy is used for cancer treatment due to a lack of effective drugs. The PI3K/Akt signaling pathway plays a very essential role in the pathogenesis of many cancers, and abnormal activation of this pathway leads to abnormal expression of a series of downstream proteins, which ultimately results in the excessive proliferation of cancer cells. Therefore, the PI3K/Akt signaling pathway is a critical target in cancer treatment. Marine drugs have attracted much attention in recent years, and studies have found that many extracts from oceanic animals, plants and microorganisms or their metabolites exert antitumor effects, including antiproliferative effects or the induction of cell cycle arrest, apoptosis or autophagy. However, most anticancer targets and the mechanisms of marine compounds remain unclear. The great potential of the development of marine drugs provides a new direction for cancer treatment. This review focuses on marine compounds that target the PI3K/Akt signaling pathway for the prevention and treatment of cancer and provides comprehensive information for those interested in research on marine drugs.

HMGN5 Silencing Suppresses Cell Biological Progression via AKT/MAPK Pathway in Human Glioblastoma Cells

HMGN5 regulates biological function and molecular transcription via combining with a nucleosome. There has been growing evidence that aberrant expression of HMGN5 is associated with malignant neoplasm development and progression. In the present study, we found that the expression of HMGN5 is significantly higher in high-grade glioblastoma tissues than in low-grade samples. To clarify the function of HMGN5 in glioblastoma, we knocked down HMGN5 in U87 and U251 glioblastoma cells via siRNA. The results demonstrated that HMGN5 was involved in the regulation of proliferation and apoptosis, migration, and invasion of glioblastoma cells. These outcomes also indicated that silencing HMGN5 possibly suppressed the expression of p-AKT and p-ERK1/2. Taken together, our research reveals that HMGN5 might be an efficient target for glioblastoma-targeted therapy.

Synthesis and Antiproliferative Activities of Novel Substituted 5-Anilino-α-Glucofuranose Derivatives

In order to find novel antitumor candidate agents with high efficiency and low toxicity, 14 novel substituted 5-anilino-α-glucofuranose derivatives have been designed, synthesized and evaluated for antiproliferative activities in vitro. Their structures were characterized by NMR (¹ H and ¹³ C) and HR-MS, and configuration (R/S) at C(5) was identified by two-dimensional ¹ H,¹ H-NOESY-NMR spectrum. Their antiproliferative activities against human tumor cells were investigated by MTT assay. The results demonstrated that most of the synthesized compounds had antiproliferative effects comparable to the reference drugs gefitinib and lapatinib. In particular, (5R)-5-O-(3-chloro-4-{[5-(4-fluorophenyl)thiophen-2-yl]methyl}anilino)-5-deoxy-1,2-O-(1-methylethylidene)-α-glucofuranose (9da) showed the most potent antiproliferative effects against SW480, A431 and A549 cells, with IC₅₀ values of 8.57, 5.15 and 15.24 μm, respectively. This work suggested 5-anilino-α-glucofuranose as an antitumor core structure that may open a new way to develop more potent anti-cancer agents.

A Systematic Review of Recently Reported Marine Derived Natural Product Kinase Inhibitors

Protein kinases are validated drug targets for a number of therapeutic areas, as kinase deregulation is known to play an essential role in many disease states. Many investigated protein kinase inhibitors are natural product small molecules or their derivatives. Many marine-derived natural products from various marine sources, such as bacteria and cyanobacteria, fungi, animals, algae, soft corals, sponges, etc. have been found to have potent kinase inhibitory activity, or desirable pharmacophores for further development. This review covers the new compounds reported from the beginning of 2014 through the middle of 2019 as having been isolated from marine organisms and having potential therapeutic applications due to kinase inhibitory and associated bioactivities. Moreover, some existing clinical drugs based on marine-derived natural product scaffolds are also discussed.

Neuroprotective Effects of AG490 in Neonatal Hypoxic-Ischemic Brain Injury

In infants and children, neonatal hypoxic-ischemic (HI) brain injury represents a major cause of chronic neurological morbidity. The transient receptor potential melastatin 2 (TRPM2), a non-selective cation channel that conducts calcium, can mediate neuronal death following HI brain injury. An important endogenous activator of TRPM2 is H₂O₂, which has previously been reported to be upregulated in the neonatal brain after hypoxic ischemic injury. Here, incorporating both in vitro (H₂O₂-induced neuronal cell death model) and in vivo (mouse HI brain injury model) approaches, we examined the effects of AG490, which can inhibit the H₂O₂-induced TRPM2 channel. We found that AG490 elicited neuroprotective effects. We confirmed that AG490 reduced H₂O₂-induced TRPM2 currents. Specifically, application of AG490 to neurons ameliorated H₂O₂-induced cell injury in vitro. In addition, AG490 administration reduced brain damage and improved neurobehavioral performance following HI brain injury in vivo. The neuroprotective benefits of AG490 suggest that pharmacological inhibition of H₂O₂-activated TRPM2 currents can be exploited as a potential therapeutic strategy to treat HI-induced neurological complications.

Wound Healing Potential of Spirulina Protein on CCD-986sk Cells

Wound healing is a dynamic and complex process. The proliferation and migration of dermal fibroblasts are crucial for wound healing. Recent studies have indicated that the extracts from Spirulina platensis have a positive potential for wound healing. However, its underlying mechanism is not fully understood. Our previous study showed that spirulina crude protein (SPCP) promoted the viability of human dermal fibroblast cell line (CCD-986sk cells). In this study, we further investigated the wound healing effect and corresponding mechanisms of SPCP on CCD-986sk cells. Bromodeoxyuridine (BrdU) assay showed that SPCP promoted the proliferation of CCD-986sk cells. The wound healing assay showed that SPCP promoted the migration of CCD-986sk cells. Furthermore, cell cycle analysis demonstrated that SPCP promoted CCD-986sk cells to enter S and G₂/M phases from G₀/G₁ phase. Western blot results showed that SPCP significantly upregulated the expression of cyclin D1, cyclin E, cyclin-dependent kinase 2 (Cdk2), cyclin-dependent kinase 4 (Cdk4), and cyclin-dependent kinase 6 (Cdk6), as well as inhibited the expression of CDK inhibitors p21 and p27 in CCD-986sk cells. In the meanwhile, SPCP promoted the phosphorylation and activation of phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt). However, the phosphorylation of Akt was significantly blocked by PI3K inhibitor (LY294002), which in turn reduced the SPCP-induced proliferation and migration of CCD-986sk cells. Therefore, the results presenting in this study suggested that SPCP can promote the proliferation and migration of CCD-986sk cells; the PI3K/Akt signaling pathway play a positive and important role in these processes.

Ion channels as therapeutic antibody targets

It is now well established that antibodies have numerous potential benefits when developed as therapeutics. Here, we evaluate the technical challenges of raising antibodies to membrane-spanning proteins together with enabling technologies that may facilitate the discovery of antibody therapeutics to ion channels. Additionally, we discuss the potential targeting opportunities in the anti-ion channel antibody landscape, along with a number of case studies where functional antibodies that target ion channels have been reported. Antibodies currently in development and progressing towards the clinic are highlighted.

Prostaglandin E2 increases migration and proliferation of human glioblastoma cells by activating transient receptor potential melastatin 7 channels

Recent studies showed that both prostaglandin E2 (PGE2) and transient receptor potential melastatin 7 (TRPM7) play important roles in migration and proliferation of human glioblastoma cells. In this study, we tested the association between PGE2 and TRPM7. We found that PGE2 increased TRPM7 currents in HEK293 and human glioblastoma A172 cells. The PGE2 EP3 receptor antagonist L‐798106 abrogated the PGE2 stimulatory effect, while EP3 agonist 17‐phenyl trinor prostaglandin E2 (17‐pt‐PGE2) mimicked the effect of PEG2 on TRPM7. The TRPM7 phosphotransferase activity‐deficient mutation, K1646R had no effect on PGE2 induced increase of TRPM7 currents. Inhibition of protein kinase A (PKA) activity by Rp‐cAMP increased TRPM7 currents. TRPM7 PKA phosphorylation site mutation S1269A abolished the PGE2 effect on TRPM7 currents. PGE2 increased both mRNA and membrane protein expression of TRPM7 in A172 cells. Knockdown of TRPM7 by shRNA abrogated the PGE2 stimulated migration and proliferation of A172 cells. Blockage of TRPM7 with 2‐aminoethoxydiphenyl borate (2‐APB) or NS8593 had a similar effect as TRPM7‐shRNA. In conclusion, our results demonstrate that PGE2 activates TRPM7 via EP3/PKA signalling pathway, and that PGE2 enhances migration and proliferation of human glioblastoma cells by up‐regulation of the TRPM7 channel.

Transcriptional repression of human epidermal growth factor receptor 2 by ClC-3 Cl- /H+ transporter inhibition in human breast cancer cells

Recent studies have indicated that the intracellular concentration of chloride ions (Cl⁻) regulates gene expression in several types of cells and that Cl⁻ modulators positively or negatively regulate the PI3K/AKT/mammalian target of rapamycin (mTOR) and signal transducer and activator of transcription (STAT)3 signaling pathways. We previously reported that the Ca²⁺‐activated Cl⁻ channel anoctamine (ANO)1 regulated human epidermal growth factor receptor 2 (HER2) transcription in breast cancer YMB‐1 cells. However, the mechanisms underlying ANO1‐regulated HER2 gene expression have not yet been elucidated. In the present study, we showed the involvement of intracellular organelle ClC‐3 Cl⁻/H⁺ transporter in HER2 transcription in breast cancer MDA‐MB‐453 cells. The siRNA‐mediated inhibition of ClC‐3, but not ANO1, markedly repressed HER2 transcription in MDA‐MB‐453 cells. Subsequently, treatments with the AKT inhibitor AZD 5363 and mTOR inhibitor everolimus significantly enhanced HER2 transcription in MDA‐MB‐453 cells, whereas that with the STAT3 inhibitor 5,15‐diphenylporphyrin (5,15‐DPP) inhibited it. AKT and mTOR inhibitors also significantly enhanced HER2 transcription in YMB‐1 cells. The siRNA‐mediated inhibition of ClC‐3 and ANO1 resulted in increased AKT phosphorylation and decreased STAT3 phosphorylation in MDA‐MB‐453 and YMB‐1 cells, respectively. The intracellular Cl⁻ channel protein CLIC1 was expressed in both cells; however, its siRNA‐mediated inhibition did not elicit the transcriptional repression of HER2. Collectively, our results demonstrate that intracellular Cl⁻ regulation by ANO1/ClC‐3 participates in HER2 transcription, mediating the PI3K/AKT/mTOR and/or STAT3 signaling pathway(s) in HER2‐positive breast cancer cells, and support the potential of ANO1/ClC‐3 blockers as therapeutic options for patients with resistance to anti‐HER2 therapies.

Blockade of the swelling-induced chloride current attenuates the mouse neonatal hypoxic-ischemic brain injury in vivo

Activation of swelling-induced Cl^- current (I_Cl,swell) during neonatal hypoxia-ischemia (HI) may induce brain damage. Hypoxic-ischemic brain injury causes chronic neurological morbidity in neonates as well as acute mortality. In this study, we investigated the role of I_Cl,swell in hypoxic-ischemic brain injury using a selective blocker, 4-(2-butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl) oxybutyric acid (DCPIB). In primary cultured cortical neurons perfusion of a 30% hypotonic solution activated I_Cl,swell, which was completely blocked by the application of DCPIB (10 μmol/L). The role of I_Cl,swell in neonatal hypoxic-ischemic brain injury in vivo was evaluated in a modified neonatal hypoxic-ischemic brain injury model. Before receiving the ischemic insult, the mouse pups were injected with DCPIB (10 mg/kg, ip). We found that pretreatment with DCPIB significantly reduced the brain damage assessed using TTC staining, Nissl staining and whole brain imaging, and improved the sensorimotor and vestibular recovery outcomes evaluated in neurobehavioural tests (i.e. geotaxis reflex, and cliff avoidance reflex). These results show that DCPIB has neuroprotective effects on neonatal hypoxic-ischemic brain injury, and that the I_Cl,swell may serve as a therapeutic target for treatment of hypoxic-ischemic encephalopathy.

Xyloketal B exerts antihypertensive effect in renovascular hypertensive rats via the NO-sGC-cGMP pathway and calcium signaling

Xyloketal B (Xyl-B) is a novel marine compound isolated from mangrove fungus Xylaria sp. (No 2508). We previously showed that Xyl-B promoted endothelial NO release and protected against atherosclerosis through the Akt/eNOS pathway. Vascular NO production regulates vasoconstriction in central and peripheral arteries and plays an important role in blood pressure control. In this study, we examined whether Xyl-B exerted an antihypertensive effect in a hypertensive rat model, and further explored the possible mechanisms underlying its antihypertensive action. Administration of Xyl-B (20 mg·kg^-1·d^-1, ip, for 12 weeks) significantly decreased the systolic and diastolic blood pressure in a two-kidney, two-clip (2K2C) renovascular hypertensive rats. In endothelium-intact and endothelium-denuded thoracic aortic rings, pretreatment with Xyl-B (20 μmol/L) significantly suppressed phenylephrine (Phe)-induced contractions, suggesting that its vasorelaxant effect was attributed to both endothelial-dependent and endothelial-independent mechanisms. We used SNP, methylene blue (MB, guanylate cyclase inhibitor) and indomethacin (IMC, cyclooxygenase inhibitor) to examine which endothelial pathway was involved, and found that MB, but not IMC, reversed the inhibitory effects of Xyl-B on Phe-induced vasocontraction. Moreover, Xyl-B increased the endothelial NO bioactivity and smooth muscle cGMP level, revealing that the NO-sGC-cGMP pathway, rather than PGI₂, mediated the anti-hypertensive effect of Xyl-B. We further showed that Xyl-B significantly attenuated KCl-induced Ca²⁺ entry in smooth muscle cells in vitro, which was supposed to be mediated by voltage-dependent Ca²⁺ channels (VDCCs), and reduced ryanodine-induced aortic contractions, which may be associated with store-operated Ca²⁺ entry (SOCE). Taken together, these findings demonstrate that Xyl-B exerts significant antihypertensive effects not only through the endothelial NO-sGC-cGMP pathway but also through smooth muscle calcium signaling, including VDCCs and SOCE.

TGFβ-induced epithelial-to-mesenchymal transition in prostate cancer cells is mediated via TRPM7 expression

Growth factors, such as the transforming growth factor beta (TGFβ), play an important role in promoting metastasis of prostate cancer, thus understanding how TGFβ could induce prostate cancer cell migration may enable us to develop targeted strategies for treatment of advanced metastatic prostate cancer. To more clearly define the mechanism(s) involved in prostate cancer cell migration, we undertook a series of studies utilizing non‐malignant prostate epithelial cells RWPE1 and prostate cancer DU145 and PC3 cells. Our studies show that increased cell migration was observed in prostate cancer cells, which was mediated through epithelial‐to‐mesenchymal transition (EMT). Importantly, addition of Mg²⁺, but not Ca²⁺, increased cell migration. Furthermore, TRPM7 expression, which functions as an Mg²⁺ influx channel, was also increased in prostate cancer cells. Inhibition of TRPM7 currents by 2‐APB, significantly blocked cell migration in both DU145 and PC3 cells. Addition of growth factor TGFβ showed a further increase in cell migration, which was again blocked by the addition of 2‐APB. Importantly, TGFβ addition also significantly increased TRPM7 expression and function, and silencing of TRPM7 negated TGFβ‐induced cell migration along with a decrease in EMT markers showing loss of cell adhesion. Furthermore, resveratrol, which decreases prostate cancer cell migration, inhibited TRPM7 expression and function including TGFβ‐induced cell migration and activation of TRPM7 function. Together, these results suggest that Mg²⁺ influx via TRPM7 promotes cell migration by inducing EMT in prostate cancer cells and resveratrol negatively modulates TRPM7 function thereby inhibiting prostate cancer metastasis.

Swelling-induced chloride current in glioblastoma proliferation, migration, and invasion

Glioblastoma (GBM) remains as the most common and aggressive brain tumor. The survival of GBM has been linked to the aberrant activation of swelling-induced chloride current I_Cl,swell . In this study, we investigated the effects of I_Cl,swell on cell viability, proliferation, and migration in the human GBM cell lines, U251 and U87, using a combination of patch clamp electrophysiology, MTT, colony formation, wound healing assays and Western immunoblotting. First, we showed that the specific inhibitor of I_Cl,swell , DCPIB, potently reduced the I_Cl,swell in U87 cells. Next, in both U87 and U251 cells, we found that DCPIB reduced GBM viability, proliferation, colony formation, migration, and invasion. In addition, our Western immunoblot assay showed that DCPIB-treated U251 cells had a reduction in JAK2, STAT3, and Akt phosphorylation, thus, suggesting that DCPIB potentially suppresses GBM functions through inhibition of the JAK2/STAT3 and PI3K/Akt signaling pathways. Therefore, the I_Cl,swell may be a potential drug target for GBM.

Xyloketal B alleviates cerebral infarction and neurologic deficits in a mouse stroke model by suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway

Xyloketal B (Xyl-B) is a novel marine compound isolated from mangrove fungus Xylaria sp. We previously demonstrated that pretreatment with Xyl-B exerted neuroprotective effects and attenuated hypoxic-ischemic brain injury in neonatal mice. In the present study we investigated the neuroprotective effects of pre- and post-treatment with Xyl-B in adult mice using a transient middle cerebral artery occlusion (tMCAO) model, and explored the underlying mechanisms. Adult male C57 mice were subjected to tMCAO surgery. For the pre-treatment, Xyl-B was given via multiple injections (12.5, 25, and 50 mg·kg^-1·d^-1, ip) 48 h, 24 h and 30 min before ischemia. For the post-treatment, a single dose of Xyl-B (50 mg/kg, ip) was injected at 0, 1 or 2 h after the onset of ischemia. The regional cerebral perfusion was monitored using a laser-Doppler flowmeter. TTC staining was performed to determine the brain infarction volume. We found that both pre-treatment with Xyl-B (50 mg/kg) and post-treatment with Xyl-B (50 mg/kg) significantly reduced the infarct volume, but had no significant hemodynamic effects. Treatment with Xyl-B also significantly alleviated the neurological deficits in tMCAO mice. Furthermore, treatment with Xyl-B significantly attenuated ROS overproduction in brain tissues; increased the MnSOD protein levels, suppressed TLR4, NF-κB and iNOS protein levels; and downregulated the mRNA levels of proinflammatory cytokines, including IL-1β, TNF-α, IL-6 and IFN-γ. Moreover, Xyl-B also protected blood-brain barrier integrity in tMCAO mice. In conclusion, Xyl-B administered within 2 h after the onset of stroke effectively protects against focal cerebral ischemia; the underlying mechanism may be related to suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway.

Activation of TRPM7 by naltriben enhances migration and invasion of glioblastoma cells

Glioblastoma (GBM), the most common and aggressive brain tumor in the central nervous system, remains a lethal diagnosis with a median survival of < 15 months. Aberrant expression of the TRPM7 channel has been linked to GBM functions. In this study, using the human GBM cell line U87, we evaluated the TRPM7 activator naltriben on GBM viability, migration, and invasiveness. First, using the whole-cell patch-clamp technique, we showed that naltriben enhanced the endogenous TRPM7-like current in U87 cells. In addition, with Fura-2 Ca²⁺ imaging, we observed robust Ca²⁺ influx following naltriben application. Naltriben significantly enhanced U87 cell migration and invasion (assessed with scratch wound assays, Matrigel invasion experiments, and MMP-2 protein expression), but not viability and proliferation (evaluated with MTT assays). Using Western immunoblots, we also detected the protein levels of p-Akt/t-Akt, and p-ERK1|2/t-ERK1|2. We found that naltriben enhanced the MAPK/ERK signaling pathway, but not the PI3k/Akt pathway. Therefore, potentiated TRPM7 activity contributes to the devastating migratory and invasive characteristics of GBM.

Role of TRPM7 in Cancer: Potential as Molecular Biomarker and Therapeutic Target

The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed ion channel with intrinsic kinase activity. Molecular and electrophysiological analyses of the structure and activity of TRPM7 have revealed functional coupling of its channel and kinase activity. Studies have indicated the important roles of TRPM7 channel-kinase in fundamental cellular processes, physiological responses, and embryonic development. Accumulating evidence has shown that TRPM7 is aberrantly expressed and/or activated in human diseases including cancer. TRPM7 plays a variety of functional roles in cancer cells including survival, cell cycle progression, proliferation, growth, migration, invasion, and epithelial-mesenchymal transition (EMT). Data from a study using mouse xenograft of human cancer show that TRPM7 is required for tumor growth and metastasis. The aberrant expression of TRPM7 and its genetic mutations/polymorphisms have been identified in various types of carcinoma. Chemical modulators of TRPM7 channel produced inhibition of proliferation, growth, migration, invasion, invadosome formation, and markers of EMT in cancer cells. Taken together, these studies suggest the potential value of exploiting TRPM7 channel-kinase as a molecular biomarker and therapeutic target in human malignancies.

Role of TRPM7 in cerebral ischaemia and hypoxia

Transient receptor potential melastatin 7 (TRPM7) channel, a calcium-permeable non-selective divalent cation channel, is broadly expressed in various cells and tissues, including the brain. TRPM7 is thought to be coupled to the metabolic state and regulate calcium homeostasis in the cell. TRPM7 takes part in a wide range of cell biology processes that affect cell growth and proliferation, as well as in embryonic development and skeleton formation. TRPM7 plays a significant role in ischaemic and hypoxic brain injury and neuronal cell death. TRPM7, as a key non-glutamate mechanism of cerebral ischaemia, also triggers an intracellular ionic imbalance and neuronal cell death in ischaemia and hypoxia. We have reported that TRPM7 is expressed in neurons of the hippocampus and cortex and activation of TRPM7 induced ischaemic neuronal cell death; suppression of TRPM7 with virally mediated gene silencing using siRNA reduced ischaemic neuronal cell death and improved neurobehavioural outcomes in vivo. Recently, we also demonstrated that inhibition of TRPM7 using pharmacological means promoted neuronal outgrowth in vitro and provided neuroprotection against brain injury to hypoxia in vivo. Thus, we have shown the contributions of TRPM7 in many physiological and pathophysiological processes, including hypoxia and ischaemia.

Endophytic fungi from mangrove inhibit lung cancer cell growth and angiogenesis in vitro

The secondary metabolites of mangrove-derived endophytic fungi contain multiple substances with novel structures and biological activities. In the present study, three types of mangrove plants, namely Kandelia candel, Rhizophora stylosa and Rhizophoraceae from Zhanjiang region including the leaves, roots and stems were collected, and endophytic fungi were isolated, purified and identified from these mangrove plants. MTT assay was used to observe the effects of the isolated endophytic fungi on the growth of A549 and NCI-H460 lung cancer cells. The effect of the endophytic fungi on lung cancer angiogenesis in vitro induced by the HPV-16 E7 oncoprotein was observed. Our results showed that 28 strains of endophytic fungi were isolated, purified and identified from the three types of mangrove plants. Ten strains of endophytic fungi significantly suppressed the growth of A549 and NCI-H460 cells. The average inhibitory rates in the A549 cells were 64.4, 59.5, 81.9, 43.9, 58.3, 56.2, 48.3, 42.4, 93.0 and 49.7%, respectively. The average inhibitory rates in the NCI-H460 cells were 41.2, 49.3, 82.7, 40.7, 53.9, 52.6, 56.8, 64.3, 91.0 and 45.6%, respectively. Particularly, three strains of endophytic fungi markedly inhibited HPV-16 E7 oncoprotein‑induced lung cancer angiogenesis in vitro. These findings contribute to the further screening of potential chemotherapeutic agents from mangrove-derived endophytic fungi.

Carvacrol Alleviates Prostate Cancer Cell Proliferation, Migration, and Invasion through Regulation of PI3K/Akt and MAPK Signaling Pathways

TRPM7 is a potential therapeutic target for treatment of prostate cancer. In this study, we investigated the effects of nonselective TRPM7 inhibitor carvacrol on cell proliferation, migration, and invasion of prostate cancer PC-3 and DU145 cells. Our results showed that carvacrol blocked TRPM7-like currents in PC-3 and DU145 cells and reduced their proliferation, migration, and invasion. Moreover, carvacrol treatment significantly decreased MMP-2, p-Akt, and p-ERK1/2 protein expression and inhibited F-actin reorganization. Furthermore, consistently, TRPM7 knockdown reduced prostate cancer cell proliferation, migration, and invasion as well. Our study suggests that carvacrol may have therapeutic potential for the treatment of prostate cancer through its inhibition of TRPM7 channels and suppression of PI3K/Akt and MAPK signaling pathways.