ABSTRACT
The present study was to investigate the role of the interaction between canonical transient receptor potential channel 1 (TRPC1) and calcium release-activated calcium modulator 1 (Orai1) in extracellular Ca-sensing receptor (CaR)-induced extracellular Ca influx and nitric oxide (NO) production. Human umbilical vein endothelial cells (HUVECs) were incubated with CaR agonist Spermine [activating store-operated calcium channels (SOC) and receptor-operated calcium channels (ROC)] alone or in combination with the following reagents: CaR negative allosteric modulator Calhex231 plus ROC analogue TPA (activating ROC and blocking SOC), Ro31-8220 (PKC inhibitor that activates SOC and blocks ROC) or Go6967 (PKCs and PKCµ inhibitor that activates SOC and blocks ROC). The protein expressions and co-localization of TRPC1 and Orai1 were determined using immunofluorescent staining. The interaction between TRPC1 and Orai1 was examined by co-immunoprecipitation. We silenced the expressions of their genes in the HUVECs by transfection of constructed TRPC1 and Orai1 shRNA plasmids. Intracellular Ca concentration ([Ca]) was detected using Ca indicator Fura-2/AM, and NO production was determined by DAF-FM staining. The results showed that TRPC1 and Orai1 protein expressions were co-located on the cell membrane of the HUVECs. Compared with Spermine+Ca group, Calhex231+ TPA+Spermine+Ca, Ro31-8220+Spermine+Ca and Go6976+Spermine+Ca groups exhibited down-regulated protein expressions of TRPC1 and Orai1 in cytoplasm and decreased co-localization on the cell membrane. Co-immunoprecipitation results showed that the interaction between TRPC1 and Orai1 was reduced by Calhex231 plus TPA, Ro31-8220 or Go6976 addition in the Spermine-stimulated HUVECs. Double knockdown of Trpc1 and Orai1 genes significantly decreased [Ca] level and NO production in all of the Spermine+Ca, Calhex231+TPA+Spermine+Ca, Ro31-8220+Spermine+Ca and Go6976+Spermine+Ca groups. These results suggest that TRPC1/Orai1 may form a complex that mediates Ca influx and No production via SOC and ROC activation.
ABSTRACT
Anoikis is a form of apoptosis induced upon cell detachment from extracellular matrix.It has been determined that acquisition of resistance to anoikis is a critical step for tumor cell metastasis.MiR-21,the most prominent oncomiR,plays an important role in tumor progression.In this study,we revealed that up-regulation of miR-21 in human esophageal adenocarcinoma (EA) is associated with lymph node metastasis and poor survival rate.Because of the established anti-apoptosis effect of miR-21,it is tempting to speculate that miR-21 might contribute to tumor metastasis by regulating anoikis,qRT-PCR analysis demonstrated that miR-21 expression in OE33/AR cells (subpopulation of human EA OE33 cells that acquired resistance to anoikis) was significantly increased.Also,transfection of miR-21 mimics provided OE33 cells resisting to anoikis.By luciferase assays,we verified that PDCD4 and PTEN were the functional targets of miR-21.In mouse model,via tail vein injection experiment,we showed that the metastasis formation of OE33 cells in vivo could be mediated by changing the miR-21 expression pattern.Taken together,our findings suggested that miR-21 was involved in the regulation of anoikis in human EA cells.Targeting miR-21 may provide a novel strategy to prevent metastasis.
ABSTRACT
Anoikis is a form of apoptosis induced upon cell detachment from extracellular matrix.It has been determined that acquisition of resistance to anoikis is a critical step for tumor cell metastasis.MiR-21,the most prominent oncomiR,plays an important role in tumor progression.In this study,we revealed that up-regulation of miR-21 in human esophageal adenocarcinoma (EA) is associated with lymph node metastasis and poor survival rate.Because of the established anti-apoptosis effect of miR-21,it is tempting to speculate that miR-21 might contribute to tumor metastasis by regulating anoikis,qRT-PCR analysis demonstrated that miR-21 expression in OE33/AR cells (subpopulation of human EA OE33 cells that acquired resistance to anoikis) was significantly increased.Also,transfection of miR-21 mimics provided OE33 cells resisting to anoikis.By luciferase assays,we verified that PDCD4 and PTEN were the functional targets of miR-21.In mouse model,via tail vein injection experiment,we showed that the metastasis formation of OE33 cells in vivo could be mediated by changing the miR-21 expression pattern.Taken together,our findings suggested that miR-21 was involved in the regulation of anoikis in human EA cells.Targeting miR-21 may provide a novel strategy to prevent metastasis.
ABSTRACT
<p><b>OBJECTIVE</b>To study the roles of stromal interaction molecule 2 (STIM2) and transient receptor potential canonical 3 (TRPC3) in extracellular Ca(2+)-sensing receptor (CaR)-induced extracellular Ca2+ influx and the production of nitric oxide (NO) in human umbilical vein endothelial cells (HUVEC).</p><p><b>METHODS</b>(1) The interaction of STIM2 and TRPC3 was determined using the immunofluorescence technique. (2) The expressions of STIM2 and TRPC3 genes were silenced in HUVEC by transfection constructed STIM2 and TRPC3 RNA interference plasmids. The interference efficiency of STIM2, TRPC3 protein and mRNA levels were determined by Western blot and real time RT-PCR, respectively. (3) The second to fifth passage of HUVEC were divided into: STIM2-002 short hairpin RNA (STIM2-002 shRNA ) + spermine + Ca2+ group and TRPC3-004 short hairpin RNA (TRPC3-004 shRNA ) + spermine + Ca2+ group; control group (spermine + Ca2+ group) and vehicle+ spermine + Ca2+ group. The four groups of cells were incubated with CaR agonist spermine, the intracellular Ca2+ concentration ([Ca2+]i) was detected using the fluorescence Ca2+ indicator Fura-2/AM, and the production of NO was determined by DAF-FM (NO fluorescent probe) of each group in HUVEC.</p><p><b>RESULTS</b>(1) Immunofluorescence technique results showed that STIM2 and TRPC3 proteinswere present in the cytoplasm of HUVEC. (2) The results of transfection constructed STIM2 and TRPC3 RNA interference plasmids demonstrated that shRNA targeted to the STIM2 and TRPC3 genes decreased STIM2 and TRPC3 mRNA levels by 88.2% and 74.0%, respectively (P < 0.05), simultaneously, the STIM2 and TRPC3 protein levels were decreased by 79.9% and 71.8%, respectively (P < 0.05). (3) Compared with spermine + Ca2+ group, the [Ca2+]i and the net NO fluorescence intensity of spermine + Ca(2+) + ShSTIM2-002 group, spermine + Ca(2+) + ShTRPC3-004 group and spermine + Ca2+ Vehicle group were not changed (P > 0.05).</p><p><b>CONCLUSION</b>STIM2 and TRPC3 do not participate in CaR-mediated Ca2+ influx and NO production individually.</p>