TRPM7生理病理学功能及其小分子调节剂的发现

TRPM7（transient receptor potential melastatin 7）通道属于TRPM亚家族，是一种具有离子通道结构域和激酶结构域的双功能跨膜蛋白。作为非选择性阳离子通道，TRPM7可通透Ca²⁺、Mg²⁺、Zn²⁺、Na⁺、K⁺等和其他微量金属离子。TRPM7在人体各组织广泛表达，参与Mg²⁺的稳态调控、细胞增殖、分化、黏附和迁移等生理过程。临床上，TRPM7功能紊乱与神经退行性疾病、中风、癌症等多种疾病关系密切。本文主要综述TRPM7通道在生理、病理及小分子调节剂方面的研究进展，为相关疾病的药物开发提供新的思路。     

埃兹蛋白的表达与非小细胞肺癌转移的关系研究

目的:探究埃兹蛋白(Ezrin)的表达与非小细胞肺癌转移的关系。方法:通过免疫组化检测Ezrin在有无转移的非小细胞肺癌组织中的表达差异,通过细胞免疫组化、western-blot、RT-PCR检测Ezrin在不同转移潜能肺癌细胞系中的表达差异,通过transwell考察Ezrin对不同转移潜能癌细胞侵袭和迁移能力的影响。结果:Ezrin蛋白在有转移的非小细胞肺癌组织中的表达水平明显高于无转移的肺癌组织,在高转移潜能肺癌细胞系中的表达高于低转移潜能细胞系,受抑制时会削弱高转移潜能肺癌细胞的迁移和侵袭能力,过表达时会增强低转移潜能肺癌细胞的侵袭和迁移能力。结论:Ezrin可能在非小细胞肺癌及其转移中发挥重要作用。     

Egfl7 与非小细胞肺癌上皮间质转化关系的研究

目的:研究Egfl7与非小细胞肺癌(NSCLC)上皮间质转化标志物E-cadherin,Vimentin的相关性,探讨Egfl7是否参与NSCLC的上皮间质转化(EMT)。方法:分别采用免疫组化法和RT-PCR法检测40例NSCLC组织和20例肺癌旁正常肺组织中Egfl7,E-cadherin和Vimentin蛋白和mRNA的表达情况。结果:1).NSCLC组织中的Egfl7蛋白和mRNA的表达水平明显高于癌旁正常肺组织;其差异有统计学意义(P<0.05)。Egfl7的表达水平与肺癌的临床分期、及淋巴结转移密切相关(p0.05)。结论:NSCLC组织中Egfl7高表达,Egfl7可能与NSCLC的侵袭性相关;Egfl7与E-cadherin呈负相关,与Vimentin表达成正相关,Egfl7可能参与了NSCLC患者的上皮间质转化(EMT)过程,阻断Egfl7信号可能会抑制NSCLC患者的ENT。     

MCM7与RACK1在肺癌中的表达及其临床意义

目的探讨MCM7与RACK1在各类型肺癌中的表达及其相关性。方法收集肺腺癌150例、鳞癌150例、大细胞癌20例和小细胞癌50例及其癌旁正常肺组织石蜡标本,采用免疫组织化学S-P法检测各类型肺癌组织和癌旁正常肺组织中MCM7与RACK1的表达,并分析二者与肺癌临床病理因素的关系。结果 MCM7与RACK1在癌组织中的表达明显高于癌旁正常肺组织;χ~2检验结果显示肺癌中MCM7与RACK1的表达均与肺癌的病理分级、淋巴结转移、组织学分类和临床TNM分期相关;Pearson相关性分析结果显示,肺癌中MCM7与RACK1的表达呈正相关;Kaplan-Meier法分析显示MCM7与RACK1高表达患者生存时间缩短。结论肺癌中MCM7与RACK1的表达呈正相关,二者表达在肺癌中起促进作用,可作为检测肺癌细胞的增殖状态、新的判断预后的重要因子,以其为靶向进行临床治疗的重要指标。     

共刺激因子B7-H3 在非小细胞肺癌中的表达研究

目的:探讨共刺激椅子B7-H3在人不同非小细胞肺癌(NSCLC)细胞系和组织中的表达及其临床意义。方法:实时定量反转录-聚合酶链式反应及蛋白印迹法检测B7-H3在5种人NSCLC细胞系中的表达量,利用免疫组化法检测121例NSCLC、33例癌旁组织及36例良性病变组织中B7-H3的表达量,并收集患者临床资料,分析B7-H3与临床参数的关系。结果:5个NSCLC细胞系中均见B7-H3的表达,A549及SPAC-1中表达较H466、H1299及H460中表达较低;B7-H3在NSCLC组织中高于癌旁组织及良性病变组织(P0.001);分化程度高者平均IOD高于分化程度中、低的患者(P0.05)。发生淋巴结转移和未发生淋巴结转移的患者B7-H3的平均IOD之间存在显著性差异(P0.05)。结论:B7-H3在NSCLC组织中高表达,可能是疾病治疗或诊断的靶因子。     

miR-182靶向抑制FBXW7表达影响非小细胞肺癌细胞增殖研究

目的:研究microRNA-182(miR-182)在非小细胞肺癌(NSCLC)组织中的表达,并探讨其对NSCLC细胞增殖的影响及作用机制。方法:采用实时荧光定量PCR (qRT-PCR)检测miR-182在11例NSCLC及相应癌旁组织中的表达情况;Western blot检测FBXW7,c-Jun,c-Myc及cyclin D蛋白的表达;将miR-182模拟物,抑制物及相应空白对照瞬时转染H460细胞后,以细胞增殖与活性检测和克隆形成实验检测细胞系的增殖情况;流式细胞术检测细胞周期和凋亡变化;荧光素酶报告基因实验证实miR-182对FBXW7的靶向性作用。结果:NSCLC组织中miR-182的相对表达水平显著高于癌旁组织(P0.05)。转染组与对照组相比,H460细胞生长、克隆形成能力显著增强,细胞周期进程加快,细胞凋亡受到抑制(P0.05)。在NSCLC组织中,FBXW7蛋白的表达水平明显低于癌旁组织(P0.05)。miR-182 mimics显著降低野生型FBXW7质粒荧光素酶的活性,然而将结合位点突变后,miR-182 mimics则不再影响荧光素酶的活性。结论:miR-182在NSCLC组织中高表达,与FBXW7之间存在靶向关系,通过下调FBXW7蛋白表达促进NSCLC细胞的增殖,参与肿瘤的发生发展,预示其可能成为一种潜在的生物标志和治疗靶点。     

非小细胞肺癌中HMGA2的表达与细胞增殖的关系

目的探讨High mobility group A2 protein（HMGA2）的表达对非小细胞肺癌生长、转移的影响,与临床病理参数和细胞增殖的关系。方法应用免疫组化法检测38例非小细胞肺癌组织（23例鳞癌,15例腺癌）及癌旁的正常肺组织标本中HMGA2和Ki-67的表达。结果HMGA2和Ki-67在癌旁的正常肺组织中均不表达,而在肺癌组织中的表达阳性率分别为39．47％、44．74％,二者在肺癌组和癌旁的正常肺组织组之间差异有显著性（P〈0．05）。HMGA2的表达在伴淋巴结转移的肺癌组织明显高于不伴有淋巴结转移的肺癌组织（P〈0．05）,而与其他临床病理参数包括肿瘤的分化程度、肿瘤大小和TNM分期以及细胞增殖指标Ki-67之间没有相关性。结论本研究显示HMGA2在非小细胞肺癌组织中异常表达,可能与肺癌的发生和进展有关。     

MMP14在非小细胞肺癌中的表达及其与预后的关系

肺癌5年生存率低,侵润和转移是导致其死亡的主要原因.探讨MMP14(matrix mettallo proteinase 14)在非小细胞肺癌(non-small cell lung cancer,NSCLC)组织中的表达,及其与浸润转移和预后的关系.通过采用免疫组化检测92例NSCLC组织及25例癌旁正常组织中MMP14蛋白的表达,并分析其与临床病理学特征及预后的关系.免疫组化结果显示,MMP14蛋白在NSCLC组织中表达的阳性率为64.1%(59/92),显著高于癌旁正常组8%(2/25)(P<0.001).MMP14阳性率与NSCLC的分化程度、T分期、淋巴结转移和TNM分期相关(P<0.05),而与性别、年龄、吸烟及组织学类型无关(P>0.05).Kaplan-meier生存曲线显示,MMP14阳性表达组的患者5年生存期显著低于阴性表达组(P=0.004).Cox多因素回归分析显示,MMP14不是NSCLC的独立预后因素(P>0.05).MMP14在肺癌的分化、浸润和转移中扮演着重要的作用,并对生存期有一定的影响.     

VEGF-C和CCR7的表达与卵巢癌淋巴结转移之间的关系

目的观察血管内皮生长因子(VEGF)-C和趋化因子受体CCR7在卵巢癌组织内的表达情况,分析VEGF-C和CCR7的表达与癌淋巴结转移之间的关系。方法取卵巢癌病例72例,其中,淋巴结转移组46例,无淋巴结转移组26例。应用免疫组化技术观察VEGF-C和CCR7在卵巢癌组织内的表达。结果 VEGF-C和CCR7主要表达于卵巢癌细胞胞浆或/和胞膜内,VEGF-C和CCR7在淋巴结转移组的阳性表达率分别是71.7%和78.2%,在无淋巴结转移组的表达率分别是30.8%和26.9%,二者在淋巴结转移组的表达率均明显高于无淋巴结转移组(P<0.01)。VEGF-C和CCR7蛋白同时阳性表达在淋巴结转移组和非淋巴结转移组中的表达率分别为65.2%和15.4%,VEGF-C和CCR7的表达具有显著的相关性(P<0.01),联合检测VEGF-C和CCR7诊断卵巢癌淋巴结转移具有较高的准确度,ROC曲线下面积达0.791。结论 VEGF-C和CCR7表达在卵巢癌淋巴结转移过程中发挥重要作用,VEGF-C和CCR7在促进卵巢癌淋巴结转移中可能具有一定的协同作用,二者联合检测有助于预示卵巢癌淋巴结转移的判断。     

TRPM7调控PI3K/AKT通路对人脑血管外膜成纤维细胞增殖和凋亡的影响

人脑血管外膜成纤维细胞(HBVAFs)的异常增殖参与了血管增殖性疾病的发生发展.该研究探讨TRPM7(transient receptor potential melastatin 7)能否通过调控PI3K/AKT信号通路影响HBVAFs增殖和凋亡.体外培养HBVAFs细胞,分为如下几组:parental(正常培养HB...     

Waixenicin A inhibits cell proliferation through magnesium-dependent block of transient receptor potential melastatin 7 (TRPM7) channels

Transient receptor potential melastatin 7 (TRPM7) channels represent the major magnesium-uptake mechanism in mammalian cells and are key regulators of cell growth and proliferation. They are expressed abundantly in a variety of human carcinoma cells controlling survival, growth, and migration. These characteristics are the basis for recent interest in the channel as a target for cancer therapeutics. We screened a chemical library of marine organism-derived extracts and identified waixenicin A from the soft coral Sarcothelia edmondsoni as a strong inhibitor of overexpressed and native TRPM7. Waixenicin A activity was cytosolic and potentiated by intracellular free magnesium (Mg(2+)) concentration. Mutating a Mg(2+) binding site on the TRPM7 kinase domain reduced the potency of the compound, whereas kinase deletion enhanced its efficacy independent of Mg(2+). Waixenicin A failed to inhibit the closely homologous TRPM6 channel and did not significantly affect TRPM2, TRPM4, and Ca(2+) release-activated Ca(2+) current channels. Therefore, waixenicin A represents the first potent and relatively specific inhibitor of TRPM7 ion channels. Consistent with TRPM7 inhibition, the compound blocked cell proliferation in human Jurkat T-cells and rat basophilic leukemia cells. Based on the ability of the compound to inhibit cell proliferation through Mg(2+)-dependent block of TRPM7, waixenicin A, or structural analogs may have cancer-specific therapeutic potential, particularly because certain cancers accumulate cytosolic Mg(2+).     

EGF enhances the migration of cancer cells by up-regulation of TRPM7

Ion channels involved in the migration of tumor cells that is required for their invasion and metastasis. In this paper, we describe the interaction of TRPM7 channel and epidermal growth factor (EGF), an important player in cancer development in the migration of lung cancer cells. The TRPM7 currents in A549 cells were first characterized by means of electrophysiology, pharmacology and RNA interference. Removing Ca²⁺ from the extracellular solution not only potentiated a large inward current, but also abolished the outward rectification. 200 μM 2-APB inhibited the outward and the inward TRPM7 currents and at the same time restored the property of outward rectification. EGF greatly enhanced the migration of A549 cells, and also markedly up-regulated the membrane protein expression of TRPM7 and the amplitude of TRPM7 currents. Depressing the function of TRPM7 with RNA interference or pharmacological agents not only reversed the EGF-enhanced migration of A549 cells but also inhibited the basal migration of A549 cells in the absence of EGF. Thus it seems that TRPM7 plays a pivotal role in the migration of A549 cells induced by EGF and thus could be a potential therapeutic target in lung cancers.     

淋巴增强因子-1与肺癌侵袭、转移的相关性研究

目的：探讨淋巴增强因子-1（LEF-1）在肺癌组织中的表达及其与肺癌侵袭转移的关系。方法：利用免疫组化技术检测不同病理分期怠者石蜡切片组织中LEF1的表达。利用real—timePCR检测不同部位组织LEF-1基因表达状况。结果：分期差的患者肺癌组织有LEF1较高水平表达。转移淋巴结组织较肿瘤组织中的LEF-1基因表达水平高。肿瘤组织较周边正常组织中的LEF-1基因表达水平高。结论：LEF-1与肺癌细胞侵袭、转移密切相关。进一步深入研究,将有助于阐明肿瘤侵袭、转移机制,为肿瘤治疗提供新的线索。     

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.     

The ion channel TRPM7 regulates zinc-depletion-induced MDMX degradation

Zinc deficiency has been linked to human diseases, including cancer. MDMX, a crucial zinc-containing negative regulator of p53, has been found to be amplified or overexpressed in various cancers and implicated in the cancer initiation and progression. We report here that zinc depletion by the ion chelator TPEN or Chelex resin results in MDMX protein degradation in a ubiquitination-independent and 20S proteasome-dependent manner. Restoration of zinc led to recovery of cellular levels of MDMX. Further, TPEN treatment inhibits growth of the MCF-7 breast cancer cell line, which is partially rescued by overexpression of MDMX. Moreover, in a mass-spectrometry-based proteomics analysis, we identified TRPM7, a zinc-permeable ion channel, as a novel MDMX-interacting protein. TRPM7 stabilizes and induces the appearance of faster migrating species of MDMX on SDS-PAGE. Depletion of TRPM7 attenuates, while TRPM7 overexpression facilitates, the recovery of MDMX levels upon adding back zinc to TPEN-treated cells. Importantly, we found that TRPM7 inhibition, like TPEN treatment, decreases breast cancer cell MCF-7 proliferation and migration. The inhibitory effect on cell migration upon TRPM7 inhibition is also partially rescued by overexpression of MDMX. Together, our data indicate that TRPM7 regulates cellular levels of MDMX in part by modulating the intracellular Zn²⁺ concentration to promote tumorigenesis.     

TRPM7 and its role in neurodegenerative diseases

Calcium (Ca²⁺) and magnesium (Mg²⁺) ions have been shown to play an important role in regulating various neuronal functions. In the present review we focus on the emerging role of transient potential melastatin-7 (TRPM7) channel in not only regulating Ca²⁺ and Mg²⁺ homeostasis necessary for biological functions, but also how alterations in TRPM7 function/expression could induce neurodegeneration. Although eight TRPM channels have been identified, the channel properties, mode of activation, and physiological responses of various TRPM channels are quite distinct. Among the known 8 TRPM channels only TRPM6 and TRPM7 channels are highly permeable to both Ca²⁺ and Mg²⁺; however here we will only focus on TRPM7 as unlike TRPM6, TRPM7 channels are abundantly expressed in neuronal cells. Importantly, the discrepancy in TRPM7 channel function and expression leads to various neuronal diseases such as Alzheimer disease (AD) and Parkinson disease (PD). Further, it is emerging as a key factor in anoxic neuronal death and in other neurodegenerative disorders. Thus, by understanding the precise involvement of the TRPM7 channels in different neurodegenerative diseases and by understanding the factors that regulate TRPM7 channels, we could uncover new strategies in the future that could evolve as new drug therapeutic targets for effective treatment of these neurodegenerative diseases.     

Suppression of TRPM7 enhances TRAIL-induced apoptosis in triple-negative breast cancer cells

Transient receptor potential cation channel subfamily M member 7 (TRPM7) composed of an ion channel and a kinase domain regulates triple-negative breast cancer (TNBC) cell migration, invasion, and metastasis, but it does not modulate TNBC proliferation. However, previous studies have shown that the combination treatment of nonselective TRPM7 channel inhibitors (2-aminoethoxydiphenyl borate and Gd³⁺) with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) increases antiproliferative effects and apoptosis in prostate cancer cells and hepatic stellate cells. We, therefore, investigated the potential role of TRPM7 in proliferation and apoptosis of TNBC cells (MDA-MB-231 and MDA-MB-468 cells) with TRAIL. We demonstrated that suppression of TRPM7 via TRPM7 knockdown or pharmacological inhibition synergistically increases TRAIL-induced antiproliferative effects and apoptosis in TNBC cells. Furthermore, we showed that the synergistic interaction might be associated with TRPM7 channel activities using combination treatments of TRAIL and TRPM7 inhibitors (NS8593 as a TRPM7 channel inhibitor and TG100-115 as a TRPM7 kinase inhibitor). We reveal that downregulation of cellular FLICE-inhibitory protein via inhibition of Ca²⁺ influx might be involved in the synergistic interaction. Our study would provide both a new role of TRPM7 in TNBC cell apoptosis and a potential combinatorial therapeutic strategy using TRPM7 inhibitors with TRAIL in the treatment of TNBC.     

Assessment of TRPM7 functions by drug-like small molecules

Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a plasma membrane ion channel linked to a cytosolic protein kinase domain. Genetic inactivation of this bi-functional protein revealed its crucial role in Ca²⁺ signalling, Mg²⁺ metabolism, immune responses, cell motility, proliferation and differentiation. Malfunctions of TRPM7 are associated with anoxic neuronal death, cardiac fibrosis, tumour progression and macrothrombocytopenia. Recently, several groups have identified small organic compounds acting as inhibitors or activators of the TRPM7 channel. In follow-up studies, the identified TRPM7 modulators were successfully used to uncover new cellular functions of TRPM7 in situ including a crucial role of TRPM7 in Ca²⁺ signaling and Ca²⁺ dependent cellular processes. Hence, TRPM7 has been defined as a promising drug target. Here, we summarize the progress in this quickly developing field.     

TRPM7 and its role in neurodegenerative diseases

Calcium (Ca²⁺) and magnesium (Mg²⁺) ions have been shown to play an important role in regulating various neuronal functions. In the present review we focus on the emerging role of transient potential melastatin-7 (TRPM7) channel in not only regulating Ca²⁺ and Mg²⁺ homeostasis necessary for biological functions, but also how alterations in TRPM7 function/expression could induce neurodegeneration. Although eight TRPM channels have been identified, the channel properties, mode of activation, and physiological responses of various TRPM channels are quite distinct. Among the known 8 TRPM channels only TRPM6 and TRPM7 channels are highly permeable to both Ca²⁺ and Mg²⁺; however here we will only focus on TRPM7 as unlike TRPM6, TRPM7 channels are abundantly expressed in neuronal cells. Importantly, the discrepancy in TRPM7 channel function and expression leads to various neuronal diseases such as Alzheimer disease (AD) and Parkinson disease (PD). Further, it is emerging as a key factor in anoxic neuronal death and in other neurodegenerative disorders. Thus, by understanding the precise involvement of the TRPM7 channels in different neurodegenerative diseases and by understanding the factors that regulate TRPM7 channels, we could uncover new strategies in the future that could evolve as new drug therapeutic targets for effective treatment of these neurodegenerative diseases.     

Cholesterol-induced activation of TRPM7 regulates cell proliferation,migration, and viability of human prostate cells

Cholesterol has been shown to promote cell proliferation/migration in many cells; however the mechanism(s) have not yet been fully identified. Here we demonstrate that cholesterol increases Ca^2 + entry via the TRPM7 channel, which promoted proliferation of prostate cells by inducing the activation of the AKT and/or the ERK pathway. Additionally, cholesterol mediated Ca^2 + entry induced calpain activity that showed a decrease in E-cadherin expression, which together could lead to migration of prostate cancer cells. An overexpression of TRPM7 significantly facilitated cholesterol dependent Ca^2 + entry, cell proliferation and tumor growth. Whereas, TRPM7 silencing or inhibition of cholesterol synthesis by statin showed a significant decrease in cholesterol-mediated activation of TRPM7, cell proliferation, and migration of prostate cancer cells. Consistent with these results, statin intake was inversely correlated with prostate cancer patients and increase in TRPM7 expression was observed in samples obtained from prostate cancer patients. Altogether, we provide evidence that cholesterol-mediated activation of TRPM7 is important for prostate cancer and have identified that TRPM7 could be essential for initiation and/or progression of prostate cancer.