Involvement of Transient Receptor Potential Melastatin 7 Channels in Sophorae Radix-induced Apoptosis in Cancer Cells: Sophorae Radix and TRPM7

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.

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.

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.

TRPM7 Ion Channel: Oncogenic Roles and Therapeutic Potential in Breast Cancer

Simple Summary

Breast cancer is the most frequently diagnosed malignant tumor and the second leading cause of cancer death in women worldwide. The risk of developing breast cancer is 12.8%, i.e., 1 in 8 people, and a woman’s risk of dying is approximately 1 in 39. Calcium signals play an important role in various cancers and transport calcium ions may have altered expression in breast cancer, such as the TRPM7 calcium permeant ion channel, where overexpression may be associated with a poor prognosis. This review focuses on the TRPM7 channel, and the oncogenic roles studied so far in breast cancer. The TRPM7 ion channel is suggested as a potential and prospective target in the diagnosis and treatment of breast cancer.

Abstract

The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a divalent cations permeant channel but also has intrinsic serine/threonine kinase activity. It is ubiquitously expressed in normal tissues and studies have indicated that it participates in important physiological and pharmacological processes through its channel-kinase activity, such as calcium/magnesium homeostasis, phosphorylation of proteins involved in embryogenesis or the cellular process. Accumulating evidence has shown that TRPM7 is overexpressed in human pathologies including breast cancer. Breast cancer is the second leading cause of cancer death in women with an incidence rate increase of around 0.5% per year since 2004. The overexpression of TRPM7 may be associated with a poor prognosis in breast cancer patients, so more efforts are needed to research a new therapeutic target. TRPM7 regulates the levels of Ca²⁺, which can alter the signaling pathways involved in survival, cell cycle progression, proliferation, growth, migration, invasion, epithelial-mesenchymal transition and thus determines cell behavior, promoting tumor development. This work provides a complete overview of the TRPM7 ion channel and its main involvements in breast cancer. Special consideration is given to the modulation of the channel as a potential target in breast cancer treatment by inhibition of proliferation, migration and invasion. Taken together, these data suggest the potential exploitation of TRPM7 channel-kinase as a therapeutic target and a diagnostic biomarker.

The Role of Transient Receptor Potential Melastatin 7 (TRPM7) in Cell Viability: A Potential Target to Suppress Breast Cancer Cell Cycle

The divalent cation-selective channel transient receptor potential melastatin 7 (TRPM7) channel was shown to affect the proliferation of some types of cancer cell. However, the function of TRPM7 in the viability of breast cancer cells remains unclear. Here we show that TRPM inhibitors suppressed the viability of TRPM7-expressing breast cancer cells. We first demonstrated that the TRPM7 inhibitors 2-aminoethyl diphenylborinate (2-APB), ginsenoside Rd (Gin Rd), and waixenicin A preferentially suppressed the viability of human embryonic kidney HEK293 overexpressing TRPM7 (HEK-M7) cells over wildtype HEK293 (WT-HEK). Next, we confirmed the effects of 2-APB on the TRPM7 channel functions by whole-cell currents and divalent cation influx. The inhibition of the viability of HEK-M7 cells by 2-APB was not mediated by the increase in cell death but by the interruption of the cell cycle. Similar to HEK-M7 cells, the viability of TRPM7-expressing human breast cancer MDA-MB-231, AU565, and T47D cells were also suppressed by 2-APB by arresting the cell cycle in the S phase. Furthermore, in a novel TRPM7 knock-out MDA-MB-231 (KO-231) cell line, decreased divalent influx and reduced proliferation were observed compared to the wildtype MDA-MB-231 cells. 2-APB and Gin Rd preferentially suppressed the viability of wildtype MDA-MB-231 cells over KO-231 by affecting the cell cycle in wildtype but not KO-231 cells. Our results suggest that TRPM7 regulates the cell cycle of breast cancers and is a potential therapeutic target.

The Calcium-Signaling Toolkit in Cancer: Remodeling and Targeting

Processes that are important in cancer progression, such as sustained cell growth, invasion to other organs, and resistance to cell death inducers, have a clear overlap with pathways regulated by Ca²⁺ signaling. It is therefore not surprising that proteins important in Ca²⁺ signaling, sometimes referred to as the "Ca²⁺ signaling toolkit," can contribute to cancer cell proliferation and invasiveness, and the ability of agents to induce cancer cell death. Ca²⁺ signaling is also critical in other aspects of cancer progression, including events in the tumor microenvironment and processes involved in the acquisition of resistance to anticancer therapies. This review will consider the role of Ca²⁺ signaling in tumor progression and highlight areas in which a better understanding of the interplay between the Ca²⁺-signaling toolkit and tumorigenesis is still required.

Linear Quantitative Profiling Method Fast Monitors Alkaloids of Sophora Flavescens That Was Verified by Tri-Marker Analyses

The present study demonstrated the use of the Linear Quantitative Profiling Method (LQPM) to evaluate the quality of Alkaloids of Sophora flavescens (ASF) based on chromatographic fingerprints in an accurate, economical and fast way. Both linear qualitative and quantitative similarities were calculated in order to monitor the consistency of the samples. The results indicate that the linear qualitative similarity (LQLS) is not sufficiently discriminating due to the predominant presence of three alkaloid compounds (matrine, sophoridine and oxymatrine) in the test samples; however, the linear quantitative similarity (LQTS) was shown to be able to obviously identify the samples based on the difference in the quantitative content of all the chemical components. In addition, the fingerprint analysis was also supported by the quantitative analysis of three marker compounds. The LQTS was found to be highly correlated to the contents of the marker compounds, indicating that quantitative analysis of the marker compounds may be substituted with the LQPM based on the chromatographic fingerprints for the purpose of quantifying all chemicals of a complex sample system. Furthermore, once reference fingerprint (RFP) developed from a standard preparation in an immediate detection way and the composition similarities calculated out, LQPM could employ the classical mathematical model to effectively quantify the multiple components of ASF samples without any chemical standard.

Inductions of Caspase-, MAPK- and ROS-dependent Apoptosis and Chemotherapeutic Effects Caused by an Ethanol Extract of Scutellaria barbata D. Don in Human Gastric Adenocarcinom Cells

OBJECTIVES

The crude extracts of Scutellaria barbata D. Don (SB) have traditionally demonstrated inhibitory effects on numerous human cancers both in vitro and in vivo. Gastric cancer is one of the most common types of cancer on world. The authors investigated the effects of an ethanol extract of Scutellaria barbata D. Don (ESB) on the growth and survival of MKN-45 cells (a human gastric adenocarcinoma cell line).

METHODS

The MKN-45 cells were treated with different concentrations of ESB, and cell death was examined using an MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Analyses of sub-G1 peaks, caspase-3 and -9 activities, and mitochondrial membrane depolarizations were conducted to determine the anti-cancer effects of SB on MKN-45 cells. Also, intracellular reactive oxygen species (ROS) generation was investigated.

RESULTS

ESB inhibited the growth of MKN-45 cells, caused cell cycle arrest, and increased the sub-G1 population. In addition, ESB markedly increased mitochondrial membrane depolarization and the activities of caspase-3 and -9. ESB exerted anti-proliferative effects on MKN-45 cells by modulating the mitogen-activated protein kinase (MAPK) signaling pathway and by increasing the generation of ROS. Furthermore, combinations of anti-cancer drugs plus ESB suppressed cell growth more than treatments with an agent or ESB, and this was especially true for cisplatin, etoposide, and doxorubicin.

CONCLUSION

ESB has a dose-dependent cytotoxic effect on MKN-45 cells and this is closely associated with the induction of apoptosis. ESB-induced apoptosis is mediated by mitochondria- , caspase- and MAPK dependent pathways. In addition, ESB enhances ROS generation and increases the chemosensitivity of MKN-45 cells. These results suggest that treatment with ESB can inhibit the proliferation and promote the apoptosis of human gastric adenocarcinoma cells by modulating the caspase-, MAPK- and ROS-dependent pathway.

Role of transient receptor potential melastatin type 7 channel in gastric cancer

Transient receptor potential (TRP) proteins are a family of ion channels, which are responsible for a wide array of cellular functions. In particular, TRP melastatin type (TRPM) 7 is expressed everywhere and permeable to divalent cations such as Mg²⁺ and Ca²⁺. It contains a channel and a kinase domain. Recent studies indicate that activation of TRPM7 plays an important role in the growth and survival of gastric cancer cells. In this review, we describe and discuss the findings of recent studies that have provided novel insights of the relation between TRPM7 and gastric cancer.

Apoptosis of AGS human gastric adenocarcinoma cells by methanolic extract of Dictamnus

BACKGROUND

The root bark of Dictamnus dasycarpus Turcz has traditionally been used in East Asia to treat skin diseases such as eczema, atopic dermatitis, and psoriasis. However, it has also been reported to exhibit an anti-proliferative effect on cancer cells.

OBJECTIVE

To investigate the anti-cancer effects of a methanol extract of Dictamnus dasycarpus root bark (MEDD) on AGS cells (a human gastric adenocarcinoma cell-line).

MATERIALS AND METHODS

An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium assay, a caspase activity assay, cell cycle analysis, mitochondrial membrane potential (MMP) measurements, and western blotting were used to investigate the anti-cancer effects of MEDD on AGS cells.

RESULTS

Treatment with MEDD significantly and concentration-dependently inhibited AGS cell growth. MEDD treatment in AGS cells led to increased accumulation of apoptotic sub-G1 phase cells in a concentration-dependent manner. Also, MEDD reduced the expressions of pro-caspase-3, -8 and -9, and increased the active form of caspase-3. Furthermore, subsequent Western blotting revealed elevated levels of poly (ADP-ribose) polymerase protein. MEDD treatment reduced levels of MMP and anti-apoptotic Bcl-2 and Bcl-xL proteins. Pretreatment with SB203580 (a specific inhibitor of p38 mitogen-activated protein kinases), SP600125 (a potent inhibitor of C-Jun N-terminal kinases), or PD98059 (a potent inhibitor of extracellular signal-regulated kinases) did not modify the effects of MEDD treatment. However, pretreatment with LY294002 (a specific inhibitor of Akt) significantly enhanced MEDD-induced cell death.

CONCLUSION

These results suggest that MEDD-mediated cell death is associated with the intrinsic apoptotic pathway and that inhibition of Akt signaling contributes to apoptosis induction by MEDD.

Buxus Microphylla var. Koreana Nakai Extract for the Treatment of Gastric Cancer

Objectives:

Buxus Microphylla var. Koreana Nakai Extract (BMKNE) is used as a folk remedy for malaria and veneral disease. In the present study, we investigated the effects of BMKNE in the growth and the survival of AGS cells, the most common human gastric adenocarcinoma cell lines.

Methods:

The AGS cells were treated with varying concentrations of BMKNE. Analyses of the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were conducted to determine whether AGS cell death occured by apoptosis. Also, to identify the role of transient receptor potential melastatin (TRPM) 7 channels in AGS cell growth and survival, we used human embryonic kidney (HEK) 293 cells overexpressed with TRPM7 channels.

Results:

Experimental results showed that the sub G1 peak, the caspase-3 and -9 activities, and the mitochondrial depolarization were increased. Therefore, BMKNE was found to induce the apoptosis of these cells, and this apoptosis was inhibited by SB203580 (a p38 mitogen-activated protein kinase (MAPK) inhibitor), and by a c-jun NH2-terminal kinase (JNK) II inhibitor. Furthermore, BMKNE inhibited TRPM7 currents and TRPM7 channel over-expressions in HEK 293 cells, exacerbating BMKNE-induced cell death.

Conclusions:

These findings indicate that BMKNE inhibits the growth and the survival of gastric cancer cells due to a blockade of the TRPM7 channel’s activity and MAPK signaling. Therefore, BMKNE is a potential drug for treatment of gastric cancer, and both the TRPM7 channel and MAPK signaling may play an important role in survival in gastric cancer cells.

Effects of Ulmi Pumilae Cortex on AGS Gastric Cancer Cells

OBJECTIVE

Ulmi Pumilae Cortex(UPC) is a deciduous tree with uneven pinnate leaves and is classified as a subfamily of Ulmuceae and contains many pharmacologically active constituents. The aim of this study was to investigate the effects of UPC on the growth and survival of AGS cells, the most common human gastric adenocarcinoma cell lines.

METHODS

The AGS cells were treated with varying concentrations of UPC. Analyses of the sub G1, caspase-3 activity, and mitochondrial depolarization were conducted to determine whether AGS cell death occured by apoptosis. Furthermore, to identify the role of the transient receptor potential melastatin (TRPM) 7 channels in AGS cell growth and survival, we used human embryonic kidney (HEK) 293 cells overexpressed with TRPM7 channels.

RESULTS

The addition of UPC to a culture medium inhibited AGS cell growth and survival. Experimental results showed that the sub G1, caspase-3 activity, and mitochondrial depolarization were increased. Furthermore, TRPM7 channel overexpression in HEK 293 cells exacerbated UPC-induced cell death.

CONCLUSION

These findings indicate that UPC inhibits the growth and survival of gastric cancer cells due to a blockade of the TRPM7 channel activity. Therefore, UPC is a potential drug for treatment of gastric cancer, and TRPM7 channels may play an important role in survival in cases of gastric cancer.