TRPV2 (transient receptor potential cation channel, subfamily V, member 2)

Review on TRPV2 (transient receptor potential cation channel, subfamily V, member 2), with data on DNA, on the protein encoded, and where the gene is implicated

Differential role of TRP channels in prostate cancer

Abstract A major clinical problem with PC (prostate cancer) is the cell's ability to survive and proliferate upon androgen withdrawal. Indeed, deregulated cell differentiation and proliferation, together with the suppression of apoptosis, provides the condition for abnormal tissue growth. Here, we examine the differential role of TRP (transient receptor potential) channels in the control of Ca 2+ homoeostasis and growth of PC cells

Estrogen regulation of TRPM8 expression in breast cancer cells

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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 μM) 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 ERα 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.</p> <p>Conclusion</p> <p>Taken together, these results show that TRPM8 channels are expressed and functional in breast cancer and that their expression is regulated by ER alpha.</p

The blockade of the transient receptor potential vanilloid type 1 and fatty acid amide hydrolase decreases symptoms and central sequelae in the medial prefrontal cortex of neuropathic rats

<p>Abstract</p> <p>Background</p> <p>Neuropathic pain is a chronic disease resulting from dysfunction within the "pain matrix". The basolateral amygdala (BLA) can modulate cortical functions and interactions between this structure and the medial prefrontal cortex (mPFC) are important for integrating emotionally salient information. In this study, we have investigated the involvement of the transient receptor potential vanilloid type 1 (TRPV1) and the catabolic enzyme fatty acid amide hydrolase (FAAH) in the morphofunctional changes occurring in the pre-limbic/infra-limbic (PL/IL) cortex in neuropathic rats.</p> <p>Results</p> <p>The effect of <it>N</it>-arachidonoyl-serotonin (AA-5-HT), a hybrid FAAH inhibitor and TPRV1 channel antagonist, was tested on nociceptive behaviour associated with neuropathic pain as well as on some phenotypic changes occurring on PL/IL cortex pyramidal neurons. Those neurons were identified as belonging to the BLA-mPFC pathway by electrical stimulation of the BLA followed by hind-paw pressoceptive stimulus application. Changes in their spontaneous and evoked activity were studied in sham or spared nerve injury (SNI) rats before or after repeated treatment with AA-5-HT. Consistently with the SNI-induced changes in PL/IL cortex neurons which underwent profound phenotypic reorganization, suggesting a profound imbalance between excitatory and inhibitory responses in the mPFC neurons, we found an increase in extracellular glutamate levels, as well as the up-regulation of FAAH and TRPV1 in the PL/IL cortex of SNI rats. Daily treatment with AA-5-HT restored cortical neuronal activity, normalizing the electrophysiological changes associated with the peripheral injury of the sciatic nerve. Finally, a single acute intra-PL/IL cortex microinjection of AA-5-HT transiently decreased allodynia more effectively than URB597 or I-RTX, a selective FAAH inhibitor or a TRPV1 blocker, respectively.</p> <p>Conclusion</p> <p>These data suggest a possible involvement of endovanilloids in the cortical plastic changes associated with peripheral nerve injury and indicate that therapies able to normalize endovanilloid transmission may prove useful in ameliorating the symptoms and central sequelae associated with neuropathic pain.</p

Orai1 contributes to the establishment of an apoptosis-resistant phenotype in prostate cancer cells

The molecular nature of calcium (Ca2+)-dependent mechanisms and the ion channels having a major role in the apoptosis of cancer cells remain a subject of debate. Here, we show that the recently identified Orai1 protein represents the major molecular component of endogenous store-operated Ca2+ entry (SOCE) in human prostate cancer (PCa) cells, and constitutes the principal source of Ca2+ influx used by the cell to trigger apoptosis. The downregulation of Orai1, and consequently SOCE, protects the cells from diverse apoptosis-inducing pathways, such as those induced by thapsigargin (Tg), tumor necrosis factor α, and cisplatin/oxaliplatin. The transfection of functional Orai1 mutants, such as R91W, a selectivity mutant, and L273S, a coiled-coil mutant, into the cells significantly decreased both SOCE and the rate of Tg-induced apoptosis. This suggests that the functional coupling of STIM1 to Orai1, as well as Orai1 Ca2+-selectivity as a channel, is required for its pro-apoptotic effects. We have also shown that the apoptosis resistance of androgen-independent PCa cells is associated with the downregulation of Orai1 expression as well as SOCE. Orai1 rescue, following Orai1 transfection of steroid-deprived cells, re-established the store-operated channel current and restored the normal rate of apoptosis. Thus, Orai1 has a pivotal role in the triggering of apoptosis, irrespective of apoptosis-inducing stimuli, and in the establishment of an apoptosis-resistant phenotype in PCa cells

Regulation of membrane ruffling by polarized STIM1 and ORAI1in cortactin-rich domains

La movilidad celular y la migración requieren la reorganización del citoesqueleto cortical en el borde principal de las células y la entrada de Ca2 + extracelular es esencial para esta reorganización. Sin embargo, la naturaleza molecular de los reguladores de esta vía es desconocida. Este trabajo contribuye a comprender el papel de STIM1 y ORAI1 en la promoción de la ondulación de la membrana al mostrar que la fosfo-STIM1 se localiza en el borde principal de las células, y que tanto phospho-STIM1 como ORAI1 se localizan conjuntamente con la cortactina (CTTN), un regulador del citoesqueleto en las zonas de rizo de la membrana. Las líneas celulares STIM1-KO y ORAI1-KO se generaron mediante la edición del genoma CRISPR / Cas9 en células U2OS. En ambos casos, las células KO presentaron una reducción notable de la entrada de Ca2 + operada por el almacén (SOCE) que se rescató mediante la expresión de STIM1-mCherry y ORAI1-mCherry. Estos resultados demostraron que SOCE regula la deformación de la membrana en el borde anterior de las células. Por otra parte, ORAI1 endógeno y ORAI1-GFP sobreexpresado coinmuno precipitado con CTTN endógeno. Este último resultado, además del fenotipo de las células KO, la preservación de la co-localización de ORAI1-CTTN durante el fruncido, y la inhibición de la rizo de la membrana por parte del inhibidor del canal de Ca2 + SKF96365, apoya aún más un vínculo funcional entre el SOCE y el fruncido de la membrana.Cell motility and migration requires the reorganization of the cortical cytoskeleton at the leading edge of cells and extracellular Ca2+ entry is essential for this reorganization. However the molecular nature of the regulators of this pathway is unknown. This work contributes to understanding the role of STIM1 and ORAI1 in the promotion of membrane ruffling by showing that phospho-STIM1 localizes at the leading edge of cells, and that both phospho-STIM1 and ORAI1 co-localize with cortactin (CTTN), a regulator of the cytoskeleton at membrane ruffling areas. STIM1-KO and ORAI1-KO cell lines were generated by CRISPR/Cas9 genome editing in U2OS cells. In both cases, KO cells presented a notable reduction of store-operated Ca2+ entry (SOCE) that was rescued by expression of STIM1-mCherry and ORAI1-mCherry. These results demonstrated that SOCE regulates membrane ruffling at the leading edge of cells. Moreover, endogenous ORAI1 and overexpressed ORAI1-GFP co-immuno precipitated with endogenous CTTN. This latter result, in addition to the KO cells’ phenotype, the preservation of ORAI1-CTTN co-localization during ruffling, and the inhibition of membrane ruffling g by the Ca2+- channel inhibitor SKF96365, further supports a functional link between SOCE and membrane ruffling.• Ministerio de Economía y Competitividad y Fondo Social Europeo. Becas BFU2011-22798 y BFU2014-52401-P, para Francisco Javier Martín Romero • Consejo de Investigación Médica. Beca MC_UU_12016 / 2, para Darío R. Alessi • Ministerio de Economía y Competitividad. Beca BES-2012-052061, para Aida María López Guerrero • Gobierno de Extremadura. Ayuda PD10081, para Patricia Tomás Martín • Ministerio de Educación, Cultura y Deporte. Beca FPU13 / 03430, para Carlos Pascual Caro • Consejo de Investigación Médica. Ayuda MR / K015869 / 1, para Graeme Ball • EMBO. Beca ASTF-311-2014, para Eulalia Pozo Guisado • Ministerio de Educación, Cultura Española y Deporte. Beca PRX14 / 00176, para Francisco Javier Martín RomeropeerReviewe

ORAI1 calcium channel orchestrates skin homeostasis

To achieve and maintain skin architecture and homeostasis, keratinocytes must intricately balance growth, differentiation, and polarized motility known to be governed by calcium. Orai1 is a pore subunit of a store-operated Ca(2+) channel that is a major molecular counterpart for Ca(2+) influx in nonexcitable cells. To elucidate the physiological significance of Orai1 in skin, we studied its functions in epidermis of mice, with targeted disruption of the orai1 gene, human skin sections, and primary keratinocytes. We demonstrate that Orai1 protein is mainly confined to the basal layer of epidermis where it plays a critical role to control keratinocyte proliferation and polarized motility. Orai1 loss of function alters keratinocyte differentiation both in vitro and in vivo. Exploring underlying mechanisms, we show that the activation of Orai1-mediated calcium entry leads to enhancing focal adhesion turnover via a PKCβ-Calpain-focal adhesion kinase pathway. Our findings provide insight into the functions of the Orai1 channel in the maintenance of skin homeostasis

Saltatory formation, sliding and dissolution of ER–PM junctions in migrating cancer cells

We demonstrated three novel forms of dynamic behaviour of junctions between the ER (endoplasmic reticulum) and the PM (plasma membrane) in migrating cancer cells: saltatory formation, long-distance sliding and dissolution. The individual ER–PM junctions formed near the leading edge of migrating cells (usually within 0.5 μm of polymerized actin and close to focal adhesions) and appeared suddenly without sliding from the interior of the cell. The long distance sliding and dissolution of ER–PM junctions accompanied the tail withdrawal

Expression of TRPC6 channels in human epithelial breast cancer cells

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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).</p> <p>Results</p> <p>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 TRPC7, 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.</p> <p>Conclusion</p> <p>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.</p