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Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, with a low overall survival rate of less than 10% and limited therapeutic options. Fluctuations in tumor microenvironment pH are a hallmark of PDAC development and progression. Many ion channels are bona fide cellular sensors of changes in pH. Yet, the interplay between the acidic tumor microenvironment and ion channel regulation in PDAC is poorly understood. In this study, we show that acid adaption increases PANC-1 cell migration but attenuates proliferation and spheroid growth, which are restored upon recovery. Moreover, acid adaptation and recovery conditions favor the plasma membrane localization of the pH-sensitive calcium (Ca

In the fight against cancer, therapeutic strategies using cisplatin are severely limited by the appearance of a resistant phenotype. While cisplatin is usually efficient at the beginning of the treatment, several patients endure resistance to this agent and face relapse. One of the reasons for this resistant phenotype is the emergence of a cell subpopulation known as cancer stem cells (CSCs). Due to their quiescent phenotype and self-renewal abilities, these cells have recently been recognized as a crucial field of investigation in cancer and treatment resistance. Changes in intracellular calcium (Ca

Scorpion α-toxins are neurotoxins that target the fast inactivation mechanism of voltage-gated sodium (Na

International audience; Pancreatic stellate cell (PSC) activation is a major event occurring during pancreatic ductal adenocarcinoma (PDAC) development. Up to now mechanisms underlying their activation by mechanical cues such as the elevated tissue pressure in PDAC remain poorly understood. Here we investigate the role of one potential mechano-transducer, TRPC1 ion channel, in PSC activation. Using pre-activated human siTRPC1 and murine TRPC1-KO PSCs, we show that TRPC1 promotes αSMA (α-smooth muscle actin) expression, the main activation marker, in cooperation with the phosphorylated SMAD2, under normal and elevated pressure. Functional studies following TRPC1 silencing demonstrate the dual role of TRPC1 in the modulation of PSC proliferation and IL-6 secretion through the activation of ERK1/2 and SMAD2 pathways. Moreover, pressurization changes the mechanical behavior of PSCs by increasing their cellular stiffness and emitted traction forces in a TRPC1-dependent manner. In summary, these results point to a role of TRPC1 channels in sensing and transducing the characteristic mechanical properties of the PDAC microenvironment in PSCs.

Simple Summary Lung cancer is recognized for having a very poor prognosis with an overall survival rate of 5-years not exceeding 15%. Platinum-doublet therapy is the most current chemotherapeutic treatment used to treat lung tumors. However, resistance to such drugs evolves rapidly in patients with non-small cell lung cancer (NSCLC) and is one of the major reasons behind therapy failure. Tumor recurrence due to chemoresistance is mainly attributed to the presence of cancer stem cells (CSCs) subpopulations. Thus, the identification of resistance actors and markers is necessary. The Orai3 channel has been recently identified as a predictive marker of metastasis and survival in resectable NSCLC tumors. Our results show, for the first time, that the Orai3 channel is able to induce chemoresistance by enriching CSCs population. Our findings present Orai3 as a promising predictive biomarker which could help with selecting chemotherapeutic drugs. Abstract The development of the resistance to platinum salts is a major obstacle in the treatment of non-small cell lung cancer (NSCLC). Among the reasons underlying this resistance is the enrichment of cancer stem cells (CSCs) populations. Several studies have reported the involvement of calcium channels in chemoresistance. The Orai3 channel is overexpressed and constitutes a predictive marker of metastasis in NSCLC tumors. Here, we investigated its role in CSCs populations induced by Cisplatin (CDDP) in two NSCLC cell lines. We found that CDDP treatment increased Orai3 expression, but not Orai1 or STIM1 expression, as well as an enhancement of CSCs markers. Moreover, Orai3 silencing or the reduction of extracellular calcium concentration sensitized the cells to CDDP and led to a reduction in the expression of Nanog and SOX-2. Orai3 contributed to SOCE (Store-operated Calcium entry) in both CDDP-treated and CD133+ subpopulation cells that overexpress Nanog and SOX-2. Interestingly, the ectopic overexpression of Orai3, in the two NSCLC cell lines, lead to an increase of SOCE and expression of CSCs markers. Furthermore, CD133+ cells were unable to overexpress neither Nanog nor SOX-2 when incubated with PI3K inhibitor. Finally, Orai3 silencing reduced Akt phosphorylation. Our work reveals a link between Orai3, CSCs and resistance to CDDP in NSCLC cells.

International audience; Hereditary xerocytosis is a dominantly inherited red cell membrane disorder caused in most cases by gain-of-function mutations in PIEZO1, encoding a mechanosensitive ion channel that translates a mechanic stimulus into calcium influx. We found that PIEZO1 was expressed early in erythroid progenitor cells, and investigated whether it could be involved in erythropoiesis, besides having a role in the homeostasis of mature red cell hydration. In UT7 cells, chemical PIEZO1 activation using YODA1 repressed glycophorin A expression by 75%. This effect was PIEZO1-dependent since it was reverted using specific short hairpin-RNA knockdown. The effect of PIEZO1 activation was confirmed in human primary progenitor cells, maintaining cells at an immature stage for longer and modifying the transcriptional balance in favor of genes associated with early erythropoiesis, as shown by a high GATA2/GATAI ratio and decreased alpha/beta-globin expression. The cell proliferation rate was also reduced, with accumulation of cells in G0/G1 of the cell cycle. The PIEZO1-mediated effect on UT7 cells required calcium-dependent activation of the NFAT and ERK1/2 pathways. In primary erythroid cells, PIEZO1 activation synergized with erythropoietin to activate STATS and ERK, indicating that it may modulate signaling pathways downstream of erythropoietin receptor activation. Finally, we studied the in-vitro erythroid differentiation of primary cells obtained from 14 PIEZO1-mutated patients, from 11 families, carrying ten different mutations. We observed a delay in erythroid differentiation in all cases, ranging from mild (n=3) to marked (n=8). Overall, these data demonstrate a role for PIEZO1 during erythropoiesis, since activation of PIEZO1 both chemically and through activating mutations - delays erythroid maturation, providing new insights into the pathophysiology of hereditary xerocytosis.

International audience; Several processes occur during tumor development including changes in cell morphology, a reorganization of the expression and distribution of the cytoskeleton proteins as well as ion channels. If cytoskeleton proteins and ion channels have been widely investigated in understanding cancer mechanisms, the interaction between these two elements and the identification of the associated signaling pathways are only beginning to emerge. In this review, we summarize the work published over the past 15 years relating to the roles played by ion channels in these mechanisms of reorganization of the cellular morphology, essential to metastatic dissemination, both through the physical interactions with elements of the cytoskeleton and by intracellular signaling pathways involved.

Simple Summary Activated pancreatic stellate cells (aPSCs), the main source of cancer-associated fibroblasts in pancreatic ductal adenocarcinoma (PDAC), are well known as the key actor of the abundant fibrotic stroma development surrounding the tumor cells. In permanent communication with the tumor cells, they enhance PDAC early spreading and limit the drug delivery. However, the understanding of PSC activation mechanisms and the associated signaling pathways is still incomplete. In this study, we aimed to evaluate the role of Ca2+, and Orai1 Ca2+ channels, in two main PSC activation processes: cell proliferation and cytokine secretion. Indeed, Ca2+ is a versatile second messenger implicated in the regulation of numerous biological processes. We believe that a better comprehension of PSC Ca2+ -dependent activation mechanisms will bring up new crucial PDAC early prognostic markers or new targeting approaches in PDAC treatment. Abstract Activated pancreatic stellate cells (aPSCs), the crucial mediator of pancreatic desmoplasia, are characterized, among others, by high proliferative potential and abundant transforming growth factor β1 (TGFβ1) secretion. Over the past years, the involvement of Ca2+ channels in PSC pathophysiology has attracted great interest in pancreatic cancer research. We, thus, aimed to investigate the role of the Orai1 Ca2+ channel in these two PSC activation processes. Using the siRNA approach, we invalided Orai1 expression and assessed the channel functionality by Ca2+ imaging, the effect on aPSC proliferation, and TGFβ1 secretion. We demonstrated the functional expression of the Orai1 channel in human aPSCs and its implication in the store-operated Ca2+ entry (SOCE). Orai1 silencing led to a decrease in aPSC proliferation, TGFβ1 secretion, and AKT activation. Interestingly, TGFβ1 induced a higher SOCE response by increasing Orai1 mRNAs and proteins and promoted both AKT phosphorylation and cell proliferation, abolished by Orai1 silencing. Together, our results highlight the role of Orai1-mediated Ca2+ entry in human aPSC pathophysiology by controlling cell proliferation and TGFβ1 secretion through the AKT signaling pathway. Moreover, we showed a TGFβ1-induced autocrine positive feedback loop by promoting the Orai1/AKT-dependent proliferation via the stimulation of Orai1 expression and function.

Despite magnesium (Mg2+) representing the second most abundant cation in the cell, its role in cellular physiology and pathology is far from being elucidated. Mg2+ homeostasis is regulated by Mg2+ transporters including Mitochondrial RNA Splicing Protein 2 (MRS2), Transient Receptor Potential Cation Channel Subfamily M, Member 6/7 (TRPM6/7), Magnesium Transporter 1 (MAGT1), Solute Carrier Family 41 Member 1 (SCL41A1), and Cyclin and CBS Domain Divalent Metal Cation Transport Mediator (CNNM) proteins. Recent data show that Mg2+ transporters may regulate several cancer cell hallmarks. In this review, we describe the expression of Mg2+ transporters in digestive cancers, the most common and deadliest malignancies worldwide. Moreover, Mg2+ transporters’ expression, correlation and impact on patient overall and disease-free survival is analyzed using Genotype Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) datasets. Finally, we discuss the role of these Mg2+ transporters in the regulation of cancer cell fates and oncogenic signaling pathways.

Known as the key effector of pancreatic fibrosis and pancreatic cancer’s desmoplastic stromal reaction development, activated pancreatic stellate cells (aPSCs) are attracting more and more the attention of pancreatic research. Since a few years, a crucial role of Ca2+ signaling in PSC’s activation processes has emerged. Although most of the work on PSCs and Ca2+ signaling has been carried on aPSCs, because once seated in culture, they become activated within 2–5 days, there are also some studies focusing on the role of Ca2+ in quiescent pancreatic stellate cells (qPSCs). In this mini-review, we reported all findings on Ca2+ signaling in qPSCs and aPSCs, in relation to pancreatic fibrosis and cancer promotion.

In recent years, it has been shown that breast cancer consists not only of neoplastic cells, but also of significant alterations in the surrounding stroma or tumor microenvironment. These alterations are now recognized as a critical element for breast cancer development and progression, as well as potential therapeutic targets. Furthermore, there is no doubt that ion channels are deregulated in breast cancer and some of which are prognostic markers of clinical outcome. Their dysregulation is also associated with aberrant signaling pathways. The number of published data on ion channels modifications by the microenvironment has significantly increased last years. Here, we summarize the state of the art on the cross talk between the tumor microenvironment and ion channels, in particular collagen 1, EGF, TGF-β, ATP, hypoxia, and pH, on the development and progression of breast cancer.

It’s now clearly established that the tumor microenvironment participates to tumor development. Among the different actors contributing to these processes, ion channels, located at the cancer cell surface, play a major role. We recently demonstrated that the association of Kv10.1, Orai1 and SPCA2 is crucial to promote the collagen-induced survival of MCF-7 breast cancer cells. By using siRNA directed against SPCA2, we shown that this protein is involved in the regulation of the activity, the expression and the sub-cellular localization of Kv10.1. In addition, it has been demonstrated that SPCA2 is involved in SICE in MCF-7 cells and that the N- and the C-terminal parts of this protein are necessary to interact and to produce Ca(2+) entry. However, no information is available about the necessary SPCA2’s important region to regulate Kv10.1. The aim of our work is to evaluate how SPCA2 could interact with Kv10.1 channel to induce survival promotion. By using different SPCA2 mutants, we evaluate the role of the N- and C-terminal sections on the expression and the activity of Kv10.1 channels. In addition, we analyzed the impact of these deletions on the collagen 1-induced cell survival. Our results bring out new information about the regulation of Kv10.1 channel through SPCA2. More specifically how the N- and C-terminus of this Ca(2+) transporter regulate Kv10.1 expression, trafficking, and function suggesting new opportunities to target Kv10.1 channels in cancer progression.

Cadmium is a xenobiotic involved in neoplastic transformation. Cadmium enters the cells through divalent cation transporters including the Transient Receptor Potential Melastatin-related 7 (TRPM7) which is known to be involved in cancer cell fate. This work aimed to study the role of TRPM7 in neoplastic transformation induced by cadmium exposure in non-cancer epithelial cells. Non-cancer epithelial cells were chronically exposed to low-dose of cadmium. TRPM7 expression and function were studied by Western-Blot, Patch-Clamp and calcium and magnesium imaging. Finally, cell migration and invasion were studied by Boyden chamber assays. Chronic cadmium exposure induced TRPM7 overexpression and increased the membrane currents (P P P P P

In recent years, it has been shown that breast cancer consists not only of neoplastic cells, but also of significant alterations in the surrounding stroma or tumor microenvironment. These alterations are now recognized as a critical element for breast cancer development and progression, as well as potential therapeutic targets. Furthermore, there is no doubt that ion channels are deregulated in breast cancer and some of which are prognostic markers of clinical outcome. Their dysregulation is also associated with aberrant signaling pathways. The number of published data on ion channels modifications by the microenvironment has significantly increased last years. Here, we summarize the state of the art on the cross talk between the tumor microenvironment and ion channels, in particular collagen 1, EGF, TGF-β, ATP, hypoxia, and pH, on the development and progression of breast cancer.

International audience; Store Operated Calcium Entry (SOCE) is the main route for calcium entry in breast cells. After it’s activation by STromal Interaction Molecule (STIM) during endoplasmic reticulum store depletion, membrane channels ORAI are the main actors of this cell calcium entry. STIM, ORAI and SOCE alterations might contribute to Breast Cancer (BC) carcinogenesis. Recently, we reported the tumor suppressor role of Signaling Lymphocytic Activation Molecule Family member 3 (SLAMF3) on HepatoCellular Carcinoma (HCC) progression. SLAMF3 has been shown to regulate the activity of immune cells by modulating the calcium influx. In this report, we aimed at exploring the role of SLAMF3 in regulating SOCE and migration of BC cells. We quantified and compared the expression of SLAMF3 and STIM1 by quantitative RT-PCR in tumor and healthy resections of 14 patients followed at the University Hospital of Amiens. The expressions of SLAMF3 and STIM1 were also quantified and compared in non-invasive T47D and invasive MDA-MB-231 cell lines by quantitative RT-PCR, Western blot and flow cytometry. We determined the Ca2+ basal entry as well as SOCE by Mn2+ quenching and calcium imaging, respectively, in T47D and MDA-MB-231 cells overexpressing SLAMF3 ectopically. The cell proliferation and migration/invasion were investigated by MTT, wound healing assay and Boyden chambers tests, respectively. First, we report the expression of SLAMF3 in mammary epithelial cells. We highlight the complete loss of SLAMF3 expression in invasive BC cell lines compared to non-invasive cells. In addition, we show that the forced expression of SLAMF3 in invasive cells down-regulate specifically the STIM1 expression in invasive compared to non-invasive mammary cell lines. Interestingly, an inverse correlation is observed between the low expression of SLAMF3 and the high expression of STIM1 in primary human BC tissues. Our results indicate that SLAMF3 reduces SOCE and therefore restricts BC cell migration by decreasing STIM1 expression. Therefore, SLAMF3 might be used as a predictive marker of BC evolution and aggressiveness.

Orai proteins are highly selective calcium channels playing an important role in calcium entry. Orai3 channels are overexpressed in breast cancer (BC) tissues, and involved in their proliferation, cell cycle progression and survival. Herein, we sought to address the involvement of Orai3 in resistance to chemotherapeutic drugs. Using high-throughput approaches, we investigated major changes induced by Orai3 overexpression, including downstream signaling mechanisms involved in BC chemotherapy resistance. Resistance was dependent on external calcium presence and thus Orai3 functionality. This effect allowed a downregulation of the p53 tumor suppressor protein expression via the pro-survival PI3K/Sgk-1/Sek-1 pathway. We demonstrated that p53 degradation occurred not only via Mdm2, but also via another unexpected E3 ubiquitin ligase, Nedd4-2. We found supporting bioinformatic evidence linking Orai3 overexpression and chemoresistance in large human BC data sets. Altogether, our results shed light on the molecular mechanisms activated in BC cells commonly found to overexpress Orai3, allowing resistance to chemotherapeutic drugs.

Breast cancer remains a research priority due to its invasive phenotype. Although the role of ion channels in cancer is now well established, the role of inositol (1,4,5)-trisphosphate (IP3) receptors (IP3Rs) remains enigmatic. If the three IP3Rs subtypes expression have been identified in various cancers, little is known about their physiological role. Here, we investigated the involvement of IP3R type 3 (IP3R3) in the migration processes of three human breast cancer cell lines showing different migration velocities: the low-migrating MCF-7 and the highly migrating and invasive MDA-MB-231 and MDA-MB-435S cell lines. We show that a higher IP3R3 expression level, but not IP3R1 nor IP3R2, is correlated to a stronger cell line migration capacity and a sustained calcium signal. Interestingly, silencing of IP3R3 highlights an oscillating calcium signaling profile and leads to a significant decrease of cell migration capacities of the three breast cancer cell lines. Conversely, stable overexpression of IP3R3 in MCF-7 cells significantly increases their migration capacities. This effect is completely reversed by IP3R3 silencing. In conclusion, we demonstrate that IP3R3 expression level increases the migration capacity of human breast cancer cells by changing the calcium signature. ispartof: Oncotarget vol:8 issue:42 pages:72324-72341 ispartof: location:United States status: published

// Mehdi Badaoui 1 , Cloe Mimsy-Julienne 1 , Charles Saby 2 , Laurence Van Gulick 2 , Marta Peretti 1 , Pierre Jeannesson 2 , Hamid Morjani 2 and Halima Ouadid-Ahidouch 1 1 Laboratory of Cellular and Molecular Physiology, EA4667, University of Picardie Jules Verne, Amiens, France 2 Extracellular Matrix and Cellular Dynamics, Faculty of Pharmacy, MEDyC Centre National de la Recherche Scientifique UMR7369, Reims University, Reims, France Correspondence to: Halima Ouadid-Ahidouch, email: halima.ahidouch-ouadid@u-picardie.fr Keywords: Kv10.1, Orai1, tumour microenvironment, survival, breast cancer Received: October 19, 2016 Accepted: May 31, 2017 Published: July 07, 2017 ABSTRACT Collagen type 1 is among the tumor microenvironment (TM) factors, that regulates proliferation, survival, migration and invasion. Ion channels are key players in interactions between tumor cells and TM. Kv10.1 has been shown to play an essential role in breast cancer cell proliferation and migration by permitting Ca 2+ influx notably via Orai1. Here, we show that human breast cancer (BC) cells growing, in culture media completely devoid of the serum and seeded on collagen 1 coating, exhibited less apoptotic rate and a decrease in Bax expression when compared to those grown on plastic. The survival conferred by collagen 1 was completely abolished by removing extracellular Ca 2+ from the culture medium. In addition, Ca 2+ entry was increased in collagen 1 condition along with increased Kv10.1 and Orai1 expressions. Moreover, collagen 1 was able to increase co-localization of Kv10.1 and Orai1 on the plasma membrane. Interestingly, silencing of Kv10.1 and Orai1 reduced survival and Ca 2+ influx without any additive effect. This calcium-dependent survival is accompanied by the activation of ERK1/2, and its pharmacological inhibition completely abolished the increase in Kv10.1 and Orai1 expressions, activities, and the cell survival induced by collagen 1. Moreover, both Kv10.1 and Orai1 knockdown reduced ERK1/2 activation but not Akt. Finally, DDR1 silencing but not β1-integrin reduced the collagen induced survival, ERK1/2 phosphorylation and the expression of Kv10.1 and Orai1. Together these data show that the Kv10.1/Orai1 complex is involved in BC cell survival and this is dependent on collagen 1/DDR1 pathway. Therefore, they represent a checkpoint of tumor progression induced by the tumor microenvironment.

Transient Receptor Potential Melastatin-related 7 (TRPM7) is a non-selective cation channel fused with a functional kinase domain. Physiologically, TRPM7 channel is involved in magnesium homeostasis, cell survival and gastrulation. The channel part is responsible for calcium, magnesium, and metal trace entries. Cation current through TRPM7 channel is inhibited by both intracellular magnesium and magnesium complexed with nucleotides. In parallel, the kinase is able to phosphorylate cytoskeleton proteins like myosin chain regulating cell tension and motility. Moreover, TRPM7 kinase domain can be cleaved by caspase and participates to apoptosis signaling. Importantly, TRPM7 channel expression is aberrant in numerous cancers including breast, glioblastoma, nasopharynx, ovarian, and pancreatic. Moreover, TRPM7 high expression is an independent biomarker of poor outcome in breast cancer. Pharmacological modulation or silencing of TRPM7 strongly affects proliferation, adhesion, migration or invasion in cancer cell lines. Nevertheless, it is still not clear by which mechanism TRPM7 channels may disturb cancer cell hallmarks. In the present review, we will discuss the role of TRPM7 channels in malignancies. In particular, we will distinguish the role of cation signaling from kinase function in order to better understand how TRPM7 channels may play a central role in cancer progression. We will also discuss the recent advances in pharmacological blockers of TRPM7 and their potential use for cancer therapy.

Orai3 channel has emerged as important player in malignant transformation. Indeed, its expression is increased in cancer and favors cell proliferation and survival by permitting calcium influx. In this study, Orai3 was overexpressed in lung adenocarcinoma as compared to their matched non-tumour samples and was associated with tumoural aggressiveness. Moreover, its expression was associated with estrogen receptor alpha (ERα) expression and visceral pleural invasion in multivariate analysis. Furthermore, both the overall survival (OS) median and the metastasis free survival (MFS) median of tumors with high Orai3 expression were lower than in low Orai3 expression regardless of cancer stage (35.01 months vs. 51.11 months for OS and 46.01 months vs. 62.04 months for MFS). In conclusion, Orai3 protein level constitutes an independent prognostic marker in lung adenocarcinoma, and a novel prognostic marker that could help selecting the patients with worst prognosis to be treated with adjuvant chemotherapy in resectable stage.

For twenty years, ion channels have been studied in cancer progression. Several information have been collected about their involvement in cancer cellular processes like cell proliferation, motility and their participation in tumour progression using in-vivo models. Tumour microenvironment is currently the focus of many researches and the highlighting of the relationship between cancer cells and surrounding elements, is expanding. One of the major physic-chemical parameter involved in tumour progression is the hypoxia conditions observed in solid cancer. Due to their position on the cell membrane, ion channels are good candidates to transduce or to be modulated by environmental modifications. Until now, few reports have been interested in the modification of ion channel activities or expression in this context, compared to other pathological situations such as ischemia reperfusion. The aim of our review is to summarize the current knowledge about the calcium and potassium channels properties in the context of hypoxia in tumours. This review could pave the way to orientate new studies around this exciting field to obtain new potential therapeutic approaches.

In the last years it has been shown that many components of tumor microenvironment (TM) can induce cell signaling that permit to breast cancer cells (BC) to maintain their aggressiveness. Ion channels have a role in mediating TM signal; recently we have demonstrated a functional collaboration between Kv10.1 and Orai1 channels in mediating the pro-survival effect of collagen 1 on BC cells. Here we show how SPCA2 (Secretory Pathway Ca2+ ATPase) has a role in this process and is able to support survival and proliferation induced by collagen 1. By participating to an auto-sustaining loop, SPCA2 enhances membrane expression of Kv10.1 and Orai1; the activity of every component of this trio is necessary to mediate a store independent calcium entry (SICE). This SICE is fundamental to maintain both the activation of the pro-survival pathway and the membrane localization and consequently the activity of the two channels. Moreover, the three proteins and the collagen receptor DDR1 are overexpressed only in aggressive tumors tissues. In this work, we propose a novel association between SPCA2, Kv10.1 and Orai1 involved in mediating transduction signals from TM to the BC cells that can be potentially exploited in the search of novel therapeutic targets specific to tumor tissues.

International audience; BACKGROUND: Carcinogenesis occurs in elastin-rich tissues and leads to local inflammation and elastolytic proteinase release. This contributes to bioactive matrix fragment (Matrikine) accumulation like elastin degradation products (EDP) stimulating tumour cell invasive and metastatic properties. We previously demonstrate that EDPs exert protumoural activities through Hsp90 secretion to stabilised extracellular proteinases.METHODS: EDP influence on cancer cell blebbing and extracellular vesicle shedding were examined with a videomicroscope coupled with confocal Yokogawa spinning disk, by transmission electron microscopy, scanning electron microscopy and confocal microscopy. The ribosomal protein SA (RPSA) elastin receptor was identified after affinity chromatography by western blotting and cell immunolocalisation. mRNA expression was studied using real-time PCR. SiRNA were used to confirm the essential role of RPSA.RESULTS: We demonstrate that extracellular matrix degradation products like EDPs induce tumour amoeboid phenotype with cell membrane blebbing and shedding of extracellular vesicle containing Hsp90 and proteinases in the extracellular space. EDPs influence intracellular calcium influx and cytoskeleton reorganisation. Among matrikines, VGVAPG and AGVPGLGVG peptides reproduced EDP effects through RPSA binding.CONCLUSIONS: Our data suggests that matrikines induce cancer cell blebbing and extracellular vesicle release through RPSAbinding, favouring dissemination, cell-to-cell communication and growth of cancer cells in metastatic sites.

International audience; In the battle against cancer cells, therapeutic modalities are drastically limited by intrinsic or acquired drug resistance. Resistance to therapy is not only common, but expected: if systemic agents used for cancer treatment are usually active at the beginning of therapy (i.e., 90% of primary breast cancers and 50% of metastases), about 30% of patients with early-stage breast cancer will have recurrent disease. Altered expression of ion channels is now considered as one of the hallmarks of cancer, and several ion channels have been linked to cancer cell resistance. While ion channels have been associated with cell death, apoptosis and even chemoresistance since the late 80s, the molecular mechanisms linking ion channel expression and/or function with chemotherapy have mostly emerged in the last ten years. In this review, we will highlight the relationships between ion channels and resistance to chemotherapy, with a special emphasis on the underlying molecular mechanisms.

Intracellular Ca2+ levels are important regulators of cell cycle and proliferation. We, and others, have previously reported the role of KCa3.1 (KCNN4) channels in regulating the membrane potential and the Ca2+ entry in association with cell proliferation. However, the relevance of KC3.1 channels in cancer prognosis as well as the molecular mechanism of Ca2+ entry triggered by their activation remain undetermined. Here, we show that RNAi-mediated knockdown of KCa3.1 and/or TRPC1 leads to a significant decrease in cell proliferation due to cell cycle arrest in the G1 phase. These results are consistent with the observed upregulation of both channels in synchronized cells at the end of G1 phase. Additionally, knockdown of TRPC1 suppressed the Ca2+ entry induced by 1-EBIO-mediated KCa3.1 activation, suggesting a functional cooperation between TRPC1 and KCa3.1 in the regulation of Ca2+ entry, possibly within lipid raft microdomains where these two channels seem to co-localize. We also show significant correlations between KCa3.1 mRNA expression and poor patient prognosis and unfavorable clinical breast cancer parameters by mining large datasets in the public domain. Together, these results highlight the importance of KCa3.1 in regulating the proliferative mechanisms in breast cancer cells as well as in providing a promising novel target in prognosis and therapy.

For twenty years, ion channels have been studied in cancer progression. Several information have been collected about their involvement in cancer cellular processes like cell proliferation, motility and their participation in tumour progression using in-vivo models. Tumour microenvironment is currently the focus of many researches and the highlighting of the relationship between cancer cells and surrounding elements, is expanding. One of the major physic-chemical parameter involved in tumour progression is the hypoxia conditions observed in solid cancer. Due to their position on the cell membrane, ion channels are good candidates to transduce or to be modulated by environmental modifications. Until now, few reports have been interested in the modification of ion channel activities or expression in this context, compared to other pathological situations such as ischemia reperfusion. The aim of our review is to summarize the current knowledge about the calcium and potassium channels properties in the context of hypoxia in tumours. This review could pave the way to orientate new studies around this exciting field to obtain new potential therapeutic approaches.

International audience; Cell morphology is altered in the migration process, and the underlying cytoskeleton remodeling is highly dependent of intracellular Ca2+ concentration. Many calcium channels are known to be involved in migration. Inositol 1,4,5-trisphosphate receptor (IP3R) was demonstrated to be implicated in breast cancer cells migration, but its involvement in morphological changes during the migration process remains unclear. In the present work, we showed that IP(3)R3 expression was correlated to cell morphology. IP(3)R3 silencing induced rounding shape and decreased adhesion in invasive breast cancer cell lines. Moreover, IP(3)R3 silencing decreased ARHGAP18 expression, RhoA activity, Cdc42 expression and (Y861)FAK phosphorylation. Interestingly, IP(3)R3 was able to regulate profilin remodeling, without inducing any myosin II reorganization. IP3R3 silencing revealed an oscillatory calcium signature, with a predominant oscillating profile occurring in early wound repair. To summarize, we demonstrated that IP3R3 is able to modulate intracellular Ca2+ availability and to coordinate the remodeling of profilin cytoskeleton organization through the ARHGAP18/RhoA/mDia1/PAK pathway.

Cell morphology is altered in the migration process, and the underlying cytoskeleton remodeling is highly dependent of intracellular Ca

Aberrant glycosylation changes on many glycoproteins are often related to cancer progression and metastasis. sp-Iminosugar-type castanospermine analogues, inhibitors of α-glucosidases, have been reported to exhibit antitumor activity. However, their effects on cell migration and the underlying molecular mechanism are not fully understood. Here, we investigated the effect of the pseudo-C-octyl glycoside 2-oxa-3-oxocastanospermine derivatives (CO-OCS) on breast cancer cells (MCF-7 and MDA-MB-231 cells), and MCF-10A mammary normal cell lines. We showed that CO-OCS treatment results in the drastic decrease of breast cancer cell migration without affecting cell proliferation. Furthermore, CO-OCS significantly reduced both the expression of β1-integrin, which is a crucial interacting partner of Focal Adhesion Kinase (FAK), and the phosphorylation rates of FAK and ERK1/2. CO-OCS also drastically reduced Ca entry through Store Operated Channels (SOC). Orai1 and Stim1, two N-glycosylated proteins, are involved in Store-Operated Calcium Entry (SOCE), and are essential for breast tumor cell migration. Our results showed that CO-OCS decreased the expression, at the protein level, of Stim1 without affecting that of Orai1. Moreover, cell migration and SOCE were attenuated by CO-OCS as well as when Stim1 was silenced. In contrast, in MCF-10A cells, CO-OCS slightly reduced cell migration, but was without effect on gene expression of Stim1, Orai1, β1-integrin, or FAK and ERK1/2 activation. Our results provide strong evidence for a significant effect of CO-OCS on breast cancer cell migration and support that this effect was associated with β1-integrin, Stim1, and FAK signaling pathways., This study was also supported by the Spanish Ministerio de Economía y Competitividad (contract numbers SAF2016‐76083‐R and CTQ2015‐64425‐C2‐1‐R), the Junta de Andalucía (contract number FQM2012‐1467) and the European Regional Development Funds (FEDER and FSE). The European Union Seventh Framework Programme (FP7‐People‐2012‐CIG), grant agreement number 333594 (to E. M. S.‐F., Marie Curie Reintegration Grant) is also acknowledged. MINECO/ICTI2013-2016/SAF2016‐76083‐R MINECO/ICTI2013-2016/CTQ2015‐64425‐C2‐1‐R

Epigenomic changes are an important feature of malignant tumors. How tumor aggressiveness is affected by DNA methylation of specific loci is largely unexplored. In genome-wide DNA methylation analyses, we identified the KCa 3.1 channel gene (KCNN4) promoter to be hypomethylated in an aggressive non-small-cell lung carcinoma (NSCLC) cell line and in patient samples. Accordingly, KCa 3.1 expression was increased in more aggressive NSCLC cells. Both findings were strong predictors for poor prognosis in lung adenocarcinoma. Increased KCa 3.1 expression was associated with aggressive features of NSCLC cells. Proliferation and migration of pro-metastatic NSCLC cells depended on KCa 3.1 activity. Mechanistically, elevated KCa 3.1 expression hyperpolarized the membrane potential, thereby augmenting the driving force for Ca(2+) influx. KCa 3.1 blockade strongly reduced the growth of xenografted NSCLC cells in mice as measured by positron emission tomography-computed tomography. Thus, loss of DNA methylation of the KCNN4 promoter and increased KCa 3.1 channel expression and function are mechanistically linked to poor survival of NSCLC patients.

As a nutritionally essential metal ion, zinc (Zn) not only constitutes a structural element for more than 3000 proteins but also plays important regulatory functions in cellular signal transduction. Zn homeostasis is tightly controlled by regulating the flux of Zn across cell membranes through specific transporters, i.e. ZnT and ZIP family proteins. Zn deficiency and malfunction of Zn transporters have been associated with many chronic diseases including cancer. However, the mechanisms underlying Zn regulatory functions in cellular signaling and their impact on the pathogenesis and progression of cancers remain largely unknown. In addition to these acknowledged multifunctions, Zn modulates a wide range of ion channels that in turn may also play an important role in cancer biology. The goal of this review is to propose how zinc deficiency, through modified Zn homeostasis, transporter activity and the putative regulatory function of Zn can influence ion channel activity, and thereby contribute to carcinogenesis and tumorigenesis. This review intends to stimulate interest in, and support for research into the understanding of Zn-modulated channels in cancers, and to search for novel biomarkers facilitating effective clinical stratification of high risk cancer patients as well as improved prevention and therapy in this emerging field.

Stormorken syndrome is a rare autosomal dominant disorder characterized by a phenotype that includes miosis, thrombocytopenia/thrombocytopathy with bleeding time diathesis, intellectual disability, mild hypocalcemia, muscle fatigue, asplenia, and ichthyosis. Using targeted sequencing and whole-exome sequencing, we identified the c.910CT transition in a STIM1 allele (p.R304W) only in patients and not in their unaffected family members. STIM1 encodes stromal interaction molecule 1 protein (STIM1), which is a finely tuned endoplasmic reticulum Ca(2+) sensor. The effect of the mutation on the structure of STIM1 was investigated by molecular modeling, and its effect on function was explored by calcium imaging experiments. Results obtained from calcium imaging experiments using transfected cells together with fibroblasts from one patient are in agreement with impairment of calcium homeostasis. We show that the STIM1 p.R304W variant may affect the conformation of the inhibitory helix and unlock the inhibitory state of STIM1. The p.R304W mutation causes a gain of function effect associated with an increase in both resting Ca(2+) levels and store-operated calcium entry. Our study provides evidence that Stormorken syndrome may result from a single-gene defect, which is consistent with Mendelian-dominant inheritance.