Animals ; Inflammation Mediators/metabolism* ; Macrophages/metabolism* ; Mice ; Stromal Interaction Molecule 1/metabolism*

OBJECTIVETo investigate the role of store-operated calcium channels (SOCs) in primary hepatocytes under conditions of calcium overload and ethanol-induced injury.

METHODSThe in vitro model of chronic ethanol-induced hepatocyte injury was established using primary hepatocytes isolated from Sprague-Dawley rats. Ethanol-induced changes (24, 48 and 72 h; 50, 100, 200, 400 and 800 mmol/L) in expression of the SOCs proteins stromal interaction molecule 1 (STIM1) and calcium release-activated calcium channel protein 1 (Oria1) were detected by qualitative PCR analysis (mRNA) and western blotting (protein). The possible role of these two SOCs proteins in the ethanol-induced extracellular calcium influx and related liver cell injury was determined by treating the cell system with various channel blockers (EGTA, La3+, and 2-APB). Cell viability was determined by MTT assay and cytosolic free calcium ion concentration was determined by flow cytometry.

RESULTSAfter 24 h of exposure to 0 (untreated) to 800 mM/L ethanol, the cell viability was reduced in a concentration-dependent manner. The 400 mmol/L concentration of ethanol decreased cell viability by 57.34% +/- 2.34%. and was chosen for use in subsequent experiments. Compared with the untreated control cells, the ethanol-treated cells showed significantly up-regulated mRNA and protein expression of both STIM1 and Orai1 at all times examined, suggesting that the ethanol-stimulated expression of STIM1 and Orai1 could persist for at least 72 h. The ethanol treatment induced increase in cytoplasmic calcium levels was significantly (and similarly) reduced by co-treatment with any of the three channel blockers.

CONCLUSIONChronic ethanol exposure can increase the expression of STIM1 and Orai1 in primary liver cells, suggesting that ethanol may increase extracellular calcium influx by up-regulating expression of these SOCs protein molecules, ultimately aggravating liver cell damage.

Animals ; Calcium ; metabolism ; Calcium Channel Blockers ; pharmacology ; Calcium Channels ; metabolism ; Calcium-Binding Proteins ; metabolism ; Cell Survival ; Cells, Cultured ; Ethanol ; adverse effects ; Hepatocytes ; drug effects ; metabolism ; Male ; Membrane Glycoproteins ; metabolism ; Primary Cell Culture ; Rats ; Rats, Sprague-Dawley ; Stromal Interaction Molecule 1

Store-operated Ca(2+) channels (SOCs) are plasma membrane Ca(2+) permeable channels activated by depletion of intracellular Ca(2+) store. Ca(2+) entry through SOCs is known as store-operated Ca(2+) entry (SOCE), which plays an important role in the functional regulation of airway smooth muscle cells (ASMCs). Protein kinase C (PKC) has been shown to have an activating or inhibiting effect on SOCE, depending on cell types and PKC isoforms that are involved. In ASMCs, the effect of PKC on SOCE has not been elucidated so far. In this study, the role of PKC in the activation of SOCE in rat ASMCs was examined by using Ca(2+) fluorescence imaging technique. The results showed that acute application of PKC activators PMA and PDBu did not affect SOCE induced by the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) inhibitor thapsigargin. The non-selective PKC inhibitor chelerythrine significantly inhibited thapsigargin- and bradykinin-induced SOCE. RT-PCR assay identified PKCα, δ and ɛ isoforms in rat ASMCs. PKCα-selective inhibitor Gö6976 and PKCɛ-inhibiting peptide Epsilon-V1-2 had no effect on SOCE; by contrast, PKCδ-selective inhibitor rottlerin attenuated SOCE dramatically, suggesting that PKCδ was the major PKC isoform involved in the activation of SOCE in ASMCs. Moreover, PKC down-regulation by extended exposure to high doses of PMA or PDBu also reduced SOCE, confirming the essential role of PKC in the activation of SOCE in ASMCs. In addition, PKC down-regulation did not influence the expression of stromal interaction molecule 1 (STIM1) and Orai1, two elementary molecules in the regulation and activation of SOCs. These results identified PKCδ as an essential PKC isoform involved in the activation of SOCE, and confirmed that PKC regulates the function of ASMCs in a SOCE-dependent manner.
Animals ; Bronchi ; metabolism ; Calcium ; metabolism ; Calcium Channels ; Calcium Signaling ; physiology ; Cells, Cultured ; Male ; Membrane Glycoproteins ; metabolism ; Myocytes, Smooth Muscle ; metabolism ; ORAI1 Protein ; Protein Kinase C-delta ; metabolism ; Rats ; Rats, Sprague-Dawley ; Stromal Interaction Molecule 1

OBJECTIVETo investigate the mechanism underlying sodium butyrate (NaB)-induced apoptosis of a human colon cancer cell line HCT-116.

METHODSThe apoptosis of HCT-116 cells induced by NaB was confirmed by hoechst33342 staining and AnnexinV+ PI assay. The changes in the intracellular localization of stromal interaction molecule (STIM1) and Orai1 following NaB treatment were detected by immunofluorescence technique. Western blotting was used to investigate the protein expression levels of STIM1 and Orai1.

RESULTSNaB induced apoptosis and caused translocation and colocalization of STIM1 and Orai1 in HCT-116 cells.

CONCLUSIONThe apoptosis of human colon cancer cells induced by NaB is correlated to the redistribution of STIM1 and Orai1.

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Butyrates ; pharmacology ; Calcium Channels ; metabolism ; HCT116 Cells ; Histone Deacetylase Inhibitors ; pharmacology ; Humans ; Membrane Proteins ; metabolism ; Neoplasm Proteins ; metabolism ; ORAI1 Protein ; Stromal Interaction Molecule 1

OBJECTIVETo investigate the effect of stromal interaction molecule 1 (STIM1) silencing on EPCs cell cycle.

METHODSRat bone marrow derived endothelial progenitor cells (EPCs) were isolated and cultured in L-DMEM with 20% FBS. Ad-si/rSTIM1 and Ad-hSTIM1 were then transfected into EPCs and the expression of STIM1 mRNA was detected by RT-PCR. The cell cycle was determined using flow cytometry analysis and intracellular free Ca2+ was measured using LSCM. Co-immunoprecipitation was performed to examine the interaction between STIM1 and TRPC1. Protein levels of inositol 1, 4, 5-trisphosphate were analyzed with ELISA assay.

RESULTSForty-eight hours after transfection, the expression of STIM1 mRNA was significantly downregulated (0.37 +/- 0.02 vs. 1.00 +/- 0.02, P < 0.05) and intracellular free Ca2+ level was significantly reduced (34.07 +/- 4.10 vs. 86.51 +/- 14.12, P < 0.05) in Ad-si/rSTIM1 group compared with control group. The cell cycle was arrested at G1 phase [(90.91 +/- 1.10)% vs. (77.10 +/- 0.56)%, P < 0.05] and the store-operated channel entry was strikingly inhibited in EPCs after treatment with Ad-si/rSTIM1. However, cotransfection of Ad-hSTIM1 with Ad-si/rSTIM1 significantly reversed these responses. Interestingly, co-immunoprecipitation study showed that STIM1 co-precipitated with TRPC1, and IP3 levels measured by ELISA were similar among three groups (P > 0.05).

CONCLUSIONsiRNA-mediated knockdown of STIM1 inhibited EPCs proliferation by reducing intracellular free Ca2+ through TRPC1-SOC signaling pathway.

Adenoviridae ; genetics ; Animals ; Cell Cycle ; Cell Proliferation ; Cells, Cultured ; Endothelial Cells ; cytology ; Gene Silencing ; Genetic Vectors ; Membrane Proteins ; genetics ; Neoplasm Proteins ; genetics ; RNA, Small Interfering ; Rats ; Stem Cells ; cytology ; Stromal Interaction Molecule 1 ; Transfection ; Transient Receptor Potential Channels ; metabolism

Store-operated calcium (Ca2+) entry (SOCE) is the principal Ca2+ entry route in non-excitable cells, including cancer cells. We previously demonstrated that Orai1 and STIM1, the molecular components of SOCE, are involved in tumorigenesis of clear cell renal cell carcinoma (CCRCC). However, a clinical relevance of Orai1 and STIM1 expression in CCRCC has been ill-defined. Here, we investigated the expression of Orai1 and STIM1 in CCRCC, and compared their expression with clinico-pathological parameters of CCRCC and the patients' outcome. Immunohistochemical staining for Orai1 and STIM1 was performed on 126 formalin fixed paraffin embedded tissue of CCRCC and western blot analysis for Orai1 was performed on the available fresh tissue. The results were compared with generally well-established clinicopathologic prognostic factors in CCRCC and patient survival. Membrane protein Orai1 is expressed in the nuclei in CCRCC, whereas STIM1 shows the cytosolic expression pattern in immunohistochemical staining. Orai1 expression level is inversely correlated with CCRCC tumor grade, whereas STIM1 expression level is not associated with tumor grade. The higher Orai1 expression is significantly associated with lower Fuhrman nuclear grade, pathologic T stage, and TNM stage and with favorable prognosis. The expression level of STIM1 is not correlated with CCRCC grade and clinical outcomes. Orai1 expression in CCRCC is associated with tumor progression and with favorable prognostic factors. These results suggest that Orai1 is an attractive prognostic marker and therapeutic target for CCRCC.
Adolescent ; Adult ; Aged ; Blotting, Western ; Carcinoma, Renal Cell/*diagnosis/metabolism/*pathology ; Female ; *Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; Kidney Neoplasms/metabolism/*pathology ; Male ; Middle Aged ; Neoplasm Proteins/genetics/metabolism ; ORAI1 Protein/genetics/*metabolism ; Prognosis ; Retrospective Studies ; Stromal Interaction Molecule 1/genetics/metabolism ; Young Adult

OBJECTIVETo explore the effects of stromal interaction molecule 1 (STIM1) on the expression of apoptosis-related proteins in prostate cancer PC-3 cells.

METHODSWe transfected the lentivirus vector STIM1-pGCSIL-GFP carrying STIM shRNA into human hormone-independent prostate cancer PC-3 cells, and 3 days later observed the transfection efficiency by fluorescence microscopy. At 7 days after transfection, we determined the expression of STIM1 in the PC-3 cells by RT-PCR and Western blot and those of apoptosis-related proteins Bcl-2, Bax, survivin and activated Caspase-3 by Western blot.

RESULTSAt 3 days, inverted microscopy revealed a transfection efficiency of > 80%. At 7 days, the STIM1 expression was significantly inhibited at both mRNA and protein levels. The Bcl-2/Bax rate was remarkably decreased as compared with that of the control group (0. 31 vs 1.24 ) , and the survivin expression was markedly reduced, 0. 14 times that of the relative expression in the control. However, the Caspase-3 cleavage was significantly activated, 1.52 times that of the control (P <0.05).

CONCLUSIONSTIM1 can be regarded as an oncogene in prostate cancer PC-3 cells. Inhibition of its expression can induce PC-3 cell apoptosis by reducing the Bcl-2/Bax rate, decreasing the survivin expression, and activating the Caspase-3 pathway.

Apoptosis ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Humans ; Inhibitor of Apoptosis Proteins ; metabolism ; Male ; Membrane Proteins ; genetics ; Neoplasm Proteins ; genetics ; Prostatic Neoplasms ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; RNA, Small Interfering ; genetics ; Stromal Interaction Molecule 1 ; Transfection ; bcl-2-Associated X Protein ; metabolism