Publications by authors named "Isabelle Dhennin-Duthille"

19 Publications

  • Page 1 of 1

Mg Transporters in Digestive Cancers.

Nutrients 2021 Jan 13;13(1). Epub 2021 Jan 13.

Université de Picardie Jules Verne, UFR des Sciences, UR-UPJV 4667, F-80000 Amiens, France.

Despite magnesium (Mg) representing the second most abundant cation in the cell, its role in cellular physiology and pathology is far from being elucidated. Mg homeostasis is regulated by Mg 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 Mg transporters may regulate several cancer cell hallmarks. In this review, we describe the expression of Mg transporters in digestive cancers, the most common and deadliest malignancies worldwide. Moreover, Mg 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 Mg transporters in the regulation of cancer cell fates and oncogenic signaling pathways.
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http://dx.doi.org/10.3390/nu13010210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828344PMC
January 2021

Ion Channel Signature in Healthy Pancreas and Pancreatic Ductal Adenocarcinoma.

Front Pharmacol 2020 16;11:568993. Epub 2020 Oct 16.

Laboratory of Cellular and Molecular Physiology, UR-4667, University of Picardie Jules Verne, Amiens, France.

Pancreatic ductal adenocarcinoma (PDAC) is the fourth most common cause of cancer-related deaths in United States and Europe. It is predicted that PDAC will become the second leading cause of cancer-related deaths during the next decades. The development of PDAC is not well understood, however, studies have shown that dysregulated exocrine pancreatic fluid secretion can contribute to pathologies of exocrine pancreas, including PDAC. The major roles of healthy exocrine pancreatic tissue are secretion of enzymes and bicarbonate rich fluid, where ion channels participate to fine-tune these biological processes. It is well known that ion channels located in the plasma membrane regulate multiple cellular functions and are involved in the communication between extracellular events and intracellular signaling pathways and can function as signal transducers themselves. Hereby, they contribute to maintain resting membrane potential, electrical signaling in excitable cells, and ion homeostasis. Despite their contribution to basic cellular processes, ion channels are also involved in the malignant transformation from a normal to a malignant phenotype. Aberrant expression and activity of ion channels have an impact on essentially all hallmarks of cancer defined as; uncontrolled proliferation, evasion of apoptosis, sustained angiogenesis and promotion of invasion and migration. Research indicates that certain ion channels are involved in the aberrant tumor growth and metastatic processes of PDAC. The purpose of this review is to summarize the important expression, localization, and function of ion channels in normal exocrine pancreatic tissue and how they are involved in PDAC progression and development. As ion channels are suggested to be potential targets of treatment they are furthermore suggested to be biomarkers of different cancers. Therefore, we describe the importance of ion channels in PDAC as markers of diagnosis and clinical factors.
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http://dx.doi.org/10.3389/fphar.2020.568993DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7596276PMC
October 2020

TRPM7/RPSA Complex Regulates Pancreatic Cancer Cell Migration.

Front Cell Dev Biol 2020 8;8:549. Epub 2020 Jul 8.

Laboratoire de Physiologie Cellulaire et Moléculaire - UR-UPJV 4667, UFR Sciences, Université de Picardie Jules Verne (UPJV), Amiens, France.

Pancreatic ductal adenocarcinoma (PDAC) is a malignancy with a very poor prognosis due to highly metastatic profile. Cell migration is an essential step of the metastatic cascade allowing cancer cells to spread toward target tissues. Recent studies strongly suggest that bioactive elastin peptides, also named elastokines or elastin-derived peptides (EDPs), are released in the extracellular microenvironment during tumoral remodeling of the stroma. EDPs stimulate cancer cell migration by interacting with their membrane receptor, ribosomal protein SA (RPSA). Others membrane proteins like ion channels are also involved in cancer cell migration. It has been recently shown that the transient receptor potential melastatin-related 7 (TRPM7) channel regulates PDAC cell migration and invasion. The objective of this work was to study the effect of EDPs on TRPM7 channel in human pancreatic cancer cells. We showed that EDPs promote MIA PaCa-2 cell migration using Boyden chamber assay. Cells transfected with a siRNA targeting TRPM7 were not able to migrate in response to EDPs indicating that TRPM7 regulated cell migration induced by these peptides. Moreover, EDPs were able to stimulate TRPM7 currents recorded by Patch-Clamp. Finally, we showed that TRPM7 channels and RPSA receptors are colocalized at the plasma membrane of human pancreatic cancer cells. Taken together, our data suggest that TRPM7/RPSA complex regulated human pancreatic cancer cell migration. This complex may be a promising therapeutic target in PDAC.
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http://dx.doi.org/10.3389/fcell.2020.00549DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7360683PMC
July 2020

Cadmium exposure enhances cell migration and invasion through modulated TRPM7 channel expression.

Arch Toxicol 2020 03 20;94(3):735-747. Epub 2020 Feb 20.

Laboratoire de Physiologie Cellulaire et Moléculaire - UR UPJV 4667, UFR Sciences, Université de Picardie Jules Verne (UPJV), 80039, Amiens, France.

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 < 0.001). Cells exposed to cadmium had higher intracellular calcium and magnesium levels (P < 0.05). TRPM7 silencing restored calcium levels but strongly decreased intracellular magnesium concentration (P < 0.001). Moreover, cadmium exposure enhanced both cell migration and invasion, but TRPM7 silencing strongly decreased these features (P < 0.001). Furthermore, mammary epithelial cells exposed to cadmium became rounded and had less cell-to-cell junctions. Cadmium exposure decreased epithelial markers while the mesenchymal ones were increased. Importantly, TRPM7 silencing was able to reverse these phenotypic modifications (P < 0.05). To summarize, our data show that chronic cadmium exposure enhanced TRPM7 expression and activity in non-cancer epithelial cells. TRPM7 overexpression induced intracellular magnesium increase and stimulated cell migration and invasion. These neoplastic properties could be linked to a TRPM7-dependent epithelial-to-mesenchymal transition reprogramming in cell exposed to cadmium. These findings provide new insights into the regulation of cell fates by cadmium exposure.
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http://dx.doi.org/10.1007/s00204-020-02674-wDOI Listing
March 2020

Ion Channels: New Actors Playing in Chemotherapeutic Resistance.

Cancers (Basel) 2019 Mar 16;11(3). Epub 2019 Mar 16.

Laboratoire de Physiologie Cellulaire et Moléculaire (EA 4667), Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France.

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.
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http://dx.doi.org/10.3390/cancers11030376DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6468599PMC
March 2019

TRPM6 is Essential for Magnesium Uptake and Epithelial Cell Function in the Colon.

Nutrients 2018 Jun 18;10(6). Epub 2018 Jun 18.

Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, I-00168 Rome, Italy.

Intestinal magnesium (Mg) uptake is essential for systemic Mg homeostasis. Colon cells express the two highly homologous transient receptor potential melastatin type (TRPM) 6 and 7 Mg channels, but their precise function and the consequences of their mutual interaction are not clear. To explore the functional role of TRPM6 and TRPM7 in the colon, we used human colon cell lines that innately express both channels and analyzed the functional consequences of genetic knocking-down, by RNA interference, or pharmacological inhibition, by NS8593, of either channel. TRPM7 silencing caused an increase in Mg influx, and correspondingly enhanced cell proliferation and migration, while downregulation of TRPM6 did not affect significantly either Mg influx or cell proliferation. Exposure to the specific TRPM6/7 inhibitor NS8593 reduced Mg influx, and consequently cell proliferation and migration, but Mg supplementation rescued the inhibition. We propose a model whereby in colon cells the functional Mg channel at the plasma membrane may consist of both TRPM7 homomers and TRPM6/7 heteromers. A different expression ratio between the two proteins may result in different functional properties. Altogether, our findings confirm that TRPM6 cannot be replaced by TRPM7, and that TRPM6/7 complexes and TRPM6/7-mediated Mg influx are indispensable in human epithelial colon cells.
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http://dx.doi.org/10.3390/nu10060784DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024373PMC
June 2018

The Transient Receptor Potential Melastatin 7 Channel Regulates Pancreatic Cancer Cell Invasion through the Hsp90α/uPA/MMP2 pathway.

Neoplasia 2017 04 8;19(4):288-300. Epub 2017 Mar 8.

Laboratoire de Physiologie Cellulaire et Moléculaire-EA4667, UFR Sciences, Université de Picardie Jules Verne, F-80039 Amiens, France; SFR CAP-Santé (FED 4231). Electronic address:

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a very poor prognosis. There is an urgent need to better understand the molecular mechanisms that regulate PDAC cell aggressiveness. The transient receptor potential melastatin 7 (TRPM7) is a nonselective cationic channel that mainly conducts Ca and Mg. TRPM7 is overexpressed in numerous malignancies including PDAC. In the present study, we used the PANC-1 and MIA PaCa-2 cell lines to specifically assess the role of TRPM7 in cell invasion and matrix metalloproteinase secretion. We show that TRPM7 regulates Mg homeostasis and constitutive cation entry in both PDAC cell lines. Moreover, cell invasion is strongly reduced by TRPM7 silencing without affecting the cell viability. Conditioned media were further studied, by gel zymography, to detect matrix metalloproteinase (MMP) secretion in PDAC cells. Our results show that MMP-2, urokinase plasminogen activator (uPA), and heat-shock protein 90α (Hsp90α) secretions are significantly decreased in TRPM7-deficient PDAC cells. Moreover, TRPM7 expression in human PDAC lymph node metastasis is correlated to the channel expression in primary tumor. Taken together, our results show that TRPM7 is involved in PDAC cell invasion through regulation of Hsp90α/uPA/MMP-2 proteolytic axis, confirming that this channel could be a promising biomarker and possibly a target for PDAC metastasis therapy.
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http://dx.doi.org/10.1016/j.neo.2017.01.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5345960PMC
April 2017

Recent Advances in Oncogenic Roles of the TRPM7 Chanzyme.

Curr Med Chem 2016 ;23(36):4092-4107

University of Picardie Jules Verne, F-80039, France.

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.
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http://dx.doi.org/10.2174/0929867323666160907162002DOI Listing
February 2017

TRPM7 involvement in cancer: a potential prognostic factor.

Magnes Res 2014 Jul-Sep;27(3):103-12

University of Picardie Jules Verne, UFR Sciences, Laboratory of Cell and Molecular Physiology, EA 4667, SFR CAP-SANTE (FED 4231), Amiens, France.

Calcium (Ca(2+)) and magnesium (Mg(2+)) are important metal elements that regulate a variety of cellular processes such as proliferation, migration, and apoptosis, in cancer cells. Among the ionic channels mediating intracellular entry, the transient receptor potential melastatin type 7 (TRPM7) channel is of particular interest, it being a non-selective, cationic channel mediating both Ca(2+) and Mg(2+) influx. TRPM7 is highly expressed in a number of human cancer tissues and cell lines. In this review, we summarise current knowledge on the physiological role of the dual function TRPM7 chanzyme, the potential application of TRPM7 as a diagnostic and prognostic marker of cancer progression with respect to clinical and pathological characteristics, and the molecular mechanisms implicated in cancerogenesis that specifically involve Ca(2+) and Mg(2+) influx through TRPM7 or kinase activity and interaction with cytoskeletal proteins.
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http://dx.doi.org/10.1684/mrh.2014.0367DOI Listing
July 2015

TRP channels: diagnostic markers and therapeutic targets for breast cancer?

Trends Mol Med 2013 Feb 17;19(2):117-24. Epub 2012 Dec 17.

University of Picardie Jules Verne, UFR Sciences, EA4667 Laboratory of Cell and Molecular Physiology, SFR CAP-SANTE, Amiens, France.

Breast cancer is the most frequently occurring cancer in women and has the highest rate of mortality. Ion channels such as the transient receptor potential (TRP) channels could play a critical role in the development and progression of cancer. Although these channels are frequently and abundantly expressed in many tumors, their expression, activity, and roles in the context of breast cancer remain poorly understood. This review summarizes our current knowledge regarding TRP channels expressed in human breast tissue, primary human breast epithelial cells, and cell lines, the functional role of TRP channels during breast cancer cell growth and migration, as well as their relationship with clinical and pathological features.
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http://dx.doi.org/10.1016/j.molmed.2012.11.004DOI Listing
February 2013

[TRP calcium channel and breast cancer: expression, role and correlation with clinical parameters].

Bull Cancer 2012 Jun;99(6):655-64

Université de Picardie Jules-Verne, laboratoire de physiologie cellulaire et moléculaire, UFR des sciences, JE 2530, 33, rue Saint-Leu, 80039 Amiens, France.

Breast cancer (BC) has the highest incidence rate in women in industrialized countries. Statistically, it is estimated that one out of 10 women will develop BC during her life. Evidence is accumulating for the role of ion channels in the development of cancer. Most studied ion channels in BC are K(+) channels, which are involved in cell proliferation, cell cycle progression and cell migration, and Na(+) channels, which correlate with invasiveness. Emerging studies demonstrated the role of Ca(2+) signaling in cancer cell proliferation, survival and migration. Recent findings demonstrated that the expression and/or activity of the transient receptor potential (TRP) channels are altered in several cancers. Among the TRP families, TRPC (canonical or classical), TRPM (melastatin) and TRPV (vanilloid) are related to malignant growth and cancer progression. Although these channels are frequently and abundantly expressed in many tumors, their specific expression, activity and roles in BC are still poorly understood. The expression of TRP channels has also been proposed as a tool for diagnosis, prognosis and/or therapeutic issues of several diseases. In cancer, TRPV6 and TRPM8 have been proposed as tumor progression markers of prostate cancer outcome and TRPC6 as a novel therapeutic target for esophageal carcinoma. Interestingly high levels of TRPC3 expression correlate with a favorable prognosis in patients with lung adenocarcinoma. Our team has recently reported the expression and role of TRPC1, TRPC6, TRPM7, TRPM8 and TRPV6 in BC cell lines and primary cultures. We have also investigated TRP expression and their clinical significance in human breast adenocarcinoma and we suggest that TRP channels are new potential BC markers. Indeed TRPC1 and TRPM8 may be considered as good prognosis markers of well-differentiated tumors, TRPM7 as a proliferative marker of poorly differentiated tumors and TRPV6 as a prognosis marker of aggressive cancers. In this review, we summarize the data reported to date regarding the changes in TRP expression associated with BC. We also discuss the importance of TRP channels in BC cells proliferation and migration and their interest as new BC markers.
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http://dx.doi.org/10.1684/bdc.2012.1595DOI Listing
June 2012

Human ether à-gogo K(+) channel 1 (hEag1) regulates MDA-MB-231 breast cancer cell migration through Orai1-dependent calcium entry.

J Cell Physiol 2012 Dec;227(12):3837-46

Laboratoire de Physiologie Cellulaire, JE 2530, UFR Sciences, 33 rue Saint-Leu, Université de Picardie Jules Verne, Amiens, France.

Breast cancer (BC) has a poor prognosis due to its strong metastatic ability. Accumulating data present ether à go-go (hEag1) K(+) channels as relevant player in controlling cell cycle and proliferation of non-invasive BC cells. However, the role of hEag1 in invasive BC cells migration is still unknown. In this study, we studied both the functional expression and the involvement in cell migration of hEag1 in the highly metastatic MDA-MB-231 human BC cells. We showed that hEag1 mRNA and proteins were expressed in human invasive ductal carcinoma tissues and BC cell lines. Functional activity of hEag1 channels in MDA-MB-231 cells was confirmed using astemizole, a hEag1 blocker, or siRNA. Blocking or silencing hEag1 depolarized the membrane potential and reduced both Ca(2+) entry and MDA-MB-231 cell migration without affecting cell proliferation. Recent studies have reported that Ca(2+) entry through Orai1 channels is required for MDA-MB-231 cell migration. Down-regulation of hEag1 or Orai1 reduced Ca(2+) influx and cell migration with similar efficiency. Interestingly, no additive effects on Ca(2+) influx or cell migration were observed in cells co-transfected with sihEag1 and siOrai1. Finally, both Orai1 and hEag1 are expressed in invasive breast adenocarcinoma tissues and invaded metastatic lymph node samples (LNM(+)). In conclusion, this study is the first to demonstrate that hEag1 channels are involved in the serum-induced migration of BC cells by controlling the Ca(2+) entry through Orai1 channels. hEag1 may therefore represent a potential target for the suppression of BC cell migration, and thus prevention of metastasis development.
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http://dx.doi.org/10.1002/jcp.24095DOI Listing
December 2012

Transient receptor potential melastatin-related 7 channel is overexpressed in human pancreatic ductal adenocarcinomas and regulates human pancreatic cancer cell migration.

Int J Cancer 2012 Sep 17;131(6):E851-61. Epub 2012 Apr 17.

Laboratory of Cell and Molecular Physiology, Faculty of Sciences, University of Picardie Jules Verne, Amiens, France.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive forms of cancer with a tendency to invade surrounding healthy tissues, leading to a largely incurable disease. Despite many advances in modern medicine, there is still a lack of early biomarkers as well as efficient therapeutical strategies. The melastatin-related transient receptor potential 7 channel (TRPM7) is a nonselective cation channel that is involved in maintaining Ca(2+) and Mg(2+) homeostasis. It has been recently reported to regulate cell differentiation, proliferation and migration. However, the role of TRPM7 in PDAC progression is far to be understood. In our study, we show that TRPM7 is 13-fold overexpressed in cancer tissues compared to the healthy ones. Furthermore, TRPM7 staining is stronger in tumors with high grade, suggesting a correlation between TRPM7 expression and PDAC progression. Importantly, TRPM7 expression is inversely related to patient survival. In BxPC-3 cell line, dialyzing the cytoplasm during the patch-clamp whole-cell recording with a 0-Mg(2+) solution activated a nonselective current with a strong outward rectification. This cation current is inhibited by intracellular Mg(2+) and by TRPM7 silencing. The downregulation of TRPM7 by small interference RNA dramatically inhibited intracellular Mg(2+) fluorescence and cell migration without affecting cell proliferation, suggesting that TRPM7 contributes to Mg(2+) entry and cell migration. Moreover, external Mg(2+) following TRPM7 silencing fully restored the cell migration. In summary, our results indicate that TRPM7 is involved in the BxPC-3 cell migration via a Mg(2+)-dependent mechanism and may be a potential biomarker of poor prognosis of PDAC.
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http://dx.doi.org/10.1002/ijc.27487DOI Listing
September 2012

High expression of transient receptor potential channels in human breast cancer epithelial cells and tissues: correlation with pathological parameters.

Cell Physiol Biochem 2011 15;28(5):813-22. Epub 2011 Dec 15.

Laboratoire de Physiologie Cellulaire, JE 2530, UFR Sciences, Université de Picardie Jules Verne, Amiens, France.

Background: Transient Receptor Potential (TRP) channels are expressed in many solid tumors. However, their expression in breast cancer remains largely unknown. Here, we investigated the profile expression of 13 TRP channels in human breast ductal adenocarcinoma (hBDA) and performed a correlation between their overexpression and pathological parameters.

Methods: The TRP channels expression was determined by RT-PCR in hBDA tissue, in human breast cancer epithelial (hBCE) primary culture and in MCF-7 cell line. The TRP protein level was evaluated by immunohistochemistry in hBDA tissue samples of 59 patients.

Results: TRPC1, TRPC6, TRPM7, TRPM8, and TRPV6 channels were overexpressed in hBDA compared to the adjacent non-tumoral tissue. Most interestingly, TRPC1, TRPM7 and TRPM8 expression strongly correlated with proliferative parameters (SBR grade, Ki67 proliferation index, and tumor size), and TRPV6 was mainly overexpressed in the invasive breast cancer cells. Using laser capture microdissection, we found that TRPV6 expression was higher in invasive areas, compared to the corresponding non-invasive ones. Moreover, TRPV6 silencing inhibited MDA-MB-231 migration and invasion, and MCF-7 migration.

Conclusion: TRP channels are aberrantly expressed in hBDA, hBCE primary cultures, and cell lines, and associated with pathological parameters. The high expression of TRP channels in tumors suggests the potential of these channels for diagnostic, prognosis and/or therapeutic approaches in human breast ductal adenocarcinoma.
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http://dx.doi.org/10.1159/000335795DOI Listing
April 2012

The tumor suppressor hTid1 inhibits STAT5b activity via functional interaction.

J Biol Chem 2011 Feb 24;286(7):5034-42. Epub 2010 Nov 24.

INSERM, U925, Université de Picardie Jules Verne, UFR de Médecine, 3 Rue des Louvels, 80036 Amiens, France.

STAT5a and -5b (signal transducers and activators of transcription 5a and 5b) proteins play an essential role in hematopoietic cell proliferation and survival and are frequently constitutively active in hematologic neoplasms and solid tumors. Because STAT5a and STAT5b differ mainly in the carboxyl-terminal transactivation domain, we sought to identify new proteins that bind specifically to this domain by using a bacterial two-hybrid screening. We isolated hTid1, a human DnaJ protein that acts as a tumor suppressor in various solid tumors. hTid1 interacts specifically with STAT5b but not with STAT5a in hematopoietic cell lines. This interaction involves the cysteine-rich region of the hTid1 DnaJ domain. We also demonstrated that hTid1 negatively regulates the expression and transcriptional activity of STAT5b and suppresses the growth of hematopoietic cells transformed by an oncogenic form of STAT5b. Our findings define hTid1 as a novel partner and negative regulator of STAT5b.
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http://dx.doi.org/10.1074/jbc.M110.155903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3037615PMC
February 2011

Estrogen regulation of TRPM8 expression in breast cancer cells.

BMC Cancer 2010 May 19;10:212. Epub 2010 May 19.

Laboratoire de Physiologie Cellulaire et Moléculaire, JE 2530: Canaux ioniques dans cancer du sein, Faculté des Sciences, Université Picardie Jules Vernes, 33 rue Saint Leu, 80000, Amiens, France.

Background: The calcium-permeable cation channel TRPM8 (melastatin-related transient receptor potential member 8) is over-expressed in several cancers. The present study aimed at investigating the expression, function and potential regulation of TRPM8 channels by ER alpha (estrogen receptor alpha) in breast cancer.

Methods: RT-PCR, Western blot, immuno-histochemical, and siRNA techniques were used to investigate TRPM8 expression, its regulation by estrogen receptors, and its expression in breast tissue. To investigate the channel activity in MCF-7 cells, we used the whole cell patch clamp and the calcium imaging techniques.

Results: TRPM8 channels are expressed at both mRNA and protein levels in the breast cancer cell line MCF-7. Bath application of the potent TRPM8 agonist Icilin (20 microM) induced a strong outwardly rectifying current at depolarizing potentials, which is associated with an elevation of cytosolic calcium concentration, consistent with established TRPM8 channel properties. RT-PCR experiments revealed a decrease in TRPM8 mRNA expression following steroid deprivation for 48 and 72 hours. In steroid deprived medium, addition of 17-beta-estradiol (E2, 10 nM) increased both TRPM8 mRNA expression and the number of cells which respond to Icilin, but failed to affect the Ca2+ entry amplitude. Moreover, silencing ERalpha mRNA expression with small interfering RNA reduced the expression of TRPM8. Immuno-histochemical examination of the expression of TRPM8 channels in human breast tissues revealed an over-expression of TRPM8 in breast adenocarcinomas, which is correlated with estrogen receptor positive (ER+) status of the tumours.

Conclusion: Taken together, these results show that TRPM8 channels are expressed and functional in breast cancer and that their expression is regulated by ER alpha.
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http://dx.doi.org/10.1186/1471-2407-10-212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2887400PMC
May 2010

Evidence that TRPM7 is required for breast cancer cell proliferation.

Am J Physiol Cell Physiol 2009 Sep 10;297(3):C493-502. Epub 2009 Jun 10.

Laboratoire de Physiologie Cellulaire et Moléculaire, Univ. Picardie Jules Verne, Faculté des Sciences, 33 Rue St Leu, 80000 Amiens, France.

Because transient receptor potential (TRP) channels have been implicated in tumor progression, we have investigated the potential role of TRPM7 channel in breast cancer cell proliferation. Under whole cell patch clamp, a Mg(2+)-inhibited cationic (MIC) current was observed in MCF-7 cells. This current was characterized by an inward current and a strong outward rectifying current that were both inhibited in a concentration-dependent manner by the presence of intracellular Mg(2+) or Mg(2+)-ATP. The inward current was reduced by La(3+), and the outward current was sensitive to 2-aminoethoxydiphenyl borate (2-APB), spermine, La(3+), and flufenamic acid. Importantly, a similar MIC current was also recorded in the primary culture of human breast cancerous epithelial cells (hBCE). Moreover, TRPM7 transcripts were found in both hBCE and MCF-7 cells. In MCF-7 cells, the MIC current was inhibited by TRPM7 small interfering RNA. Interestingly, we found that cell proliferation and intracellular Ca(2+) concentration were also reduced by TRPM7 silencing in MCF-7 cells. TRPM7 channels were also found in both human breast cancer and healthy tissues. Importantly, TRPM7 channel was overexpressed in grade III breast cancer samples associated with important Ki67 or tumor size. Our findings strongly suggest that TRPM7 is involved in the proliferative potentiality of breast cancer cells, probably by regulating Ca(2+) influx.
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http://dx.doi.org/10.1152/ajpcell.00624.2008DOI Listing
September 2009

Expression of TRPC6 channels in human epithelial breast cancer cells.

BMC Cancer 2008 May 2;8:125. Epub 2008 May 2.

Laboratoire de Physiologie Cellulaire et Moléculaire, JE Canaux ioniques dans le cancer du sein, Faculté des Sciences, Université de Picardie Jules Verne, 33 Rue St Leu 80039, Amiens, France.

Background: TRP channels have been shown to be involved in tumour generation and malignant growth. However, the expression of these channels in breast cancer remains unclear. Here we studied the expression and function of endogenous TRPC6 channels in a breast cancer cell line (MCF-7), a human breast cancer epithelial primary culture (hBCE) and in normal and tumour breast tissues.

Methods: Molecular (Western blot and RT-PCR), and immunohistochemical techniques were used to investigate TRPC6 expression. To investigate the channel activity in both MCF-7 cells and hBCE we used electrophysiological technique (whole cell patch clamp configuration).

Results: A non selective cationic current was activated by the oleoyl-2-acetyl-sn-glycerol (OAG) in both hBCE and MCF-7 cells. OAG-inward current was inhibited by 2-APB, SK&F 96365 and La3+. TRPC6, but not TRPM7, was expressed both in hBCE and in MCF-7 cells. TRPC3 was only expressed in hBCE. Clinically, TRPC6 mRNA and protein were elevated in breast carcinoma specimens in comparison to normal breast tissue. Furthermore, we found that the overexpression of TRPC6 protein levels were not correlated with tumour grades, estrogen receptor expression or lymph node positive tumours.

Conclusion: Our results indicate that TRPC6 channels are strongly expressed and functional in breast cancer epithelial cells. Moreover, the overexpression of these channels appears without any correlation with tumour grade, ER expression and lymph node metastasis. Our findings support the idea that TRPC6 may have a role in breast carcinogenesis.
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http://dx.doi.org/10.1186/1471-2407-8-125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2409351PMC
May 2008

Activated STAT5 proteins induce activation of the PI 3-kinase/Akt and Ras/MAPK pathways via the Gab2 scaffolding adapter.

Biochem J 2005 Aug;390(Pt 1):359-66

INSERM E0351, Laboratoire d'Immunologie, Faculté de Médecine, Université de Picardie Jule Verne, 3 rue des Louvels, 80036 Amiens, France.

The active forms of STAT5A (signal transducer and activator of transcription 5A) and STAT5B are able to relieve the cytokine dependence of haematopoietic cells and to induce leukaemia in mice. We have demonstrated previously that activation of the PI3K (phosphoinositide 3-kinase) signalling cascade plays a major role in cell growth and survival induced by these proteins. Interaction between STAT5 and p85, the regulatory subunit of the PI3K, has been suggested to be required for this activation. We show in the present study that the scaffolding protein Gab2 [Grb2 (growth-factor-receptor-bound protein 2)-associated binder-2] is an essential component of this interaction. Gab2 is persistently tyrosine-phosphorylated in Ba/F3 cells expressing caSTAT5 (constitutively activated STAT5), independent of JAK2 (Janus kinase 2) activation where it interacts with STAT5, p85 and Grb2, but not with Shp2 [SH2 (Src homology 2)-domain-containing tyrosine phosphatase] proteins. Interaction of STAT5 with Gab2 was also observed in Ba/F3 cells stimulated with interleukin-3 or expressing the oncogenic fusion protein Tel-JAK2. The MAPKs (mitogen-activated protein kinases) ERK1 (extracellular-signal-regulated kinase 1) and ERK2 were constitutively activated in the caSTAT5-expressing cells and were found to be required for caSTAT5-induced cell proliferation. Overexpression of Gab2-3YF, a mutant of Gab2 incapable of binding PI3K, inhibited the proliferation and survival of caSTAT5-expressing cells as well as ERK1/2 and Akt/protein kinase B phosphorylation. Taken together, our results indicate that Gab2 is required for caSTAT5-induced cell proliferation by regulating both the PI3K/Akt and the Ras/MAPK pathways.
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http://dx.doi.org/10.1042/BJ20041523DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1188271PMC
August 2005