High expression of BIRC5 enhances cell viability,inhibits apoptosis and is associated with poor prognosis in gastric cancer

AIM To investigate the expression of baculoviral inhibitor of apoptosis protein repeat-containing protein 5 （BIRC5） in gastric cancer tissue and its relationship with prognosis of gastric cancer patients, and to explore the effect of BIRC5 knock-down on the viability and apoptosis of gastric cancer cells. METHODS The expression of BIRC5 was detected by immunohistochemistry in 67 cases of gastric cancer tissues and paracancerous tissues for analyzing the relationships with clinicopathological characteristics. The mRNA and protein expression levels of BIRC5 in gastric carcinoma cell lines （AGS, MKN-1 and MGC-803） and normal gastric epithelial cell line GES-1 were detected by RT-qPCR and Western blot. The AGS cells were divided into blank group （no treatment）, Ctr-sh group （blank plasmid transfection） and BIRC5-sh group （BIRC5-shRNA plasmid transfection）. The interference efficiency of BIRC5-shRNA was evaluated by Western blot. The cell viability was measured by MTT assay, the apoptosis was analyzed by flow cytometry, and the levels of apoptosis-related proteins cleaved caspase-3, Bax and Bcl-2 were determined by Western blot. RESULTS BIRC5 was mainly expressed in cytoplasm, and the positive expression rate of BIRC5 in the gastric cancer tissues was higher than that in the adjacent tissues （P<0.01）. The positive rates of BIRC5 in the gastric cancer patients at TNM Ⅲ~Ⅳ stages and with lymph node metastasis were higher than those in the patients at TNM Ⅰ~Ⅱ stages and without lymph node metastasis, respectively （P<0.05）. The survival time of the patients with positive BIRC5 expression was shorter than that of the patients with negative BIRC5 expression （P=0.011 2）. The cell viability in BIRC5-sh group was lower than that in blank group and Ctr-sh group at time points of 48, 72 and 96 h. The apoptotic rate in BIRC5-sh group was increased compared with blank group and Ctr-sh group. The protein levels of cleaved caspase-3 and Bax in BIRC5-sh group were higher than those in blank group and Ctr-sh group, while the protein expression of Bcl-2 in BIRC5-sh group was lower than that in blank group and Ctr-sh group （P<0.05）. CONCLUSION High expression of BIRC5 in gastric cancer indicates poor prognosis. BIRC5 promotes the growth of gastric cancer cells and inhibits apoptosis.     

Effect of down-regulation of X-box binding protein 1 gene expression on viability and apoptosis of glioma cells

AIM: To investigate the effect of down-regulation of X-box binding protein 1 (XBP1) expression on the viability and apoptosis of glioma cells. METHODS: The mRNA expression of XBP1 in the glioma tissues was detected by qPCR. Small interfering RNA (siRNA) interfering with XBP1 expression (XBP1-siRNA) was transfected into human brain glioma U251 cells. At the same time, control group (the cells without special treatment) and negative control (NC-siRNA) group (transfected with siRNA without any interference) were set up. The mRNA expression of XBP1 in the 3 groups 48 h after transfection was detected by qPCR. The protein levels of XBP1, proliferating cell nuclear antigen (PCNA), B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (Bax), cyclin D1 (cyclin D1), phosphatidylinositol 3-kinase (PI3K) and phosphorylated Akt (p-Akt) were determined by Western blot. The cell viability was measured by CCK-8 assay. The cell cycle distribution and apoptosis were analyzed by flow cytometry. RESULTS: The expression level of XBP1 in the glioma tissues was significantly higher than that in the tumor adjacent tissues (P<0.05). The XBP1 expression at mRNA and protein levels was significantly decreased in the cells transfected with XBP1-siRNA (P<0.05). No statistically significant difference of the cell viability, cell cycle, apoptotic rate and the protein levels of PCNA, Bcl-2, Bax, cyclin D1, PI3K and p-Akt between NC-siRNA group and control group was observed. Compared with control group, the cell viability, S-phase cells and the protein levels of PCNA, Bcl-2, cyclin D1, PI3K, and p-Akt in XBP1-siRNA group were decreased significantly, and the apoptotic rate, G₀/G₁-phase cells and Bax protein expression were significantly increased (P<0.05). CONCLUSION: Down-regulation of XBP1 gene expression in brain glioma cells reduces the viability of cancer cells, blocks the cells in G₁ phase and promote apoptosis. The mechanism is related to the inhibition of PI3K/Akt signaling pathway.     

Inhibitory effect of poncirin on viability of gastric cancer cells and underlying mechanism

AIM: To explore the effect of poncirin on the growth of AGS gastric cancer cells and the underlying mechanism.METHODS: The effect of poncirin on AGS cell viability was measure by MTT assay. The cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Nuclear staining with DAPI was used to reflect the morphological change of the AGS cells treated with poncirin. The protein levels of extrinsic apoptosis pathway-related proteins such as FasL, caspase-8, caspase-3 and PARP, and mitochondria-mediated intrinsic apoptosis pathway-associated proteins such as Bak, Bcl-xL, Bax and caspase-9 were determined by Western blot.RESULTS: Poncirin inhibited the viability of AGS gastric cancer cells in a time-and concentration-dependent manner (P<0.05). Poncirin induced accumulation of G₁ DNA content and significantly increased total apoptosis in the AGS cells. Nuclear staining showed a dose-dependent increase in the number of apoptotic cells after treated with poncirin.The protein level of FasL was upregulated in a dose-dependent manner by treatment with poncirin. Poncirin significantly activated caspase-8 and caspase-3. Moreover, poncirin significantly induced the cleavage of PARP in a dose-dependent manner (P<0.05). In addition, the protein levels of Bcl-xL, Bax and Bak were unchanged after treated with different doses of poncirin. Furthermore, caspase-9 was not activated by poncirin treatment in the AGS cells.CONCLUSION: Poncirin has the anti-cancer effect via extrinsic apoptosis pathway to inhibit the growth of AGS gastric cancer cells, possibly making it a therapeutic agent for human gastric cancer treatment.     

STC-1 mediates proliferation and apoptosis of gastric cancer cells through Bcl-2

AIM To investigate the effect of stanniocalcin-1 （STC-1） on the proliferation and apoptosis of gastric cancer AGS cells and the role of Bcl-2 in these processes. METHODS The AGS cells were transfected with the plasmids for STC-1 knockdown or over-expression. The cell proliferation was measured by MTT assay and colony formation assay. The migration ability was detected by scratch assay. Apoptosis was analyzed by Hoechst 33342 staining and flow cytometry with annexin V-FITC/PI double staining. The protein expression of Bcl-2, survivin, caspase-3 and cleared caspase-3 was determined by Western blot. The mRNA expression levels of STC-1 and Bcl-2 in 20 cases of clinical gastric cancer tissues and adjacent tissues were detected by RT-qPCR, and the correlation between them was analyzed by Pearson method. RESULTS After over-expression of STC-1, the proliferation and migration abilities of the AGS cells were increased, the expression of Bcl-2 and survivin was increased, while the expression of caspase-3 and cleared caspase-3 was decreased （P<0.05）. After knockdown of STC-1, the proliferation and migration abilities of the AGS cells were decreased, the expression of Bcl-2 and survivin was decreased, while the expression of caspase-3 and cleared caspase-3 was increased （P<0.05）. The mRNA expression levels of STC-1 and Bcl-2 in the gastric cancer tissues were higher than those in the adjacent tissues. Pearson correlation analysis showed that there was a positive correlation between STC-1 and Bcl-2 mRNA expression in the cancer tissues （r=0.308, P=0.011）. CONCLUSION STC-1 may regulate the biological function of gastric cancer cells by altering the expression level of Bcl-2.     

Effect of captopril on AGS nude mouse model of gastric cancer

AIM: To observe the effect of captopril on the genesis and development of gastric cancer, and to explore its clinical treatment feasibility for gastric cancer. METHODS: The human gastric cancer cell line AGS was used to establish a tumor model in nude mice, and the model mice were randomly divided into 3 groups: positive control (5-fluorouracil) group, normal control (saline) group and experimental (captopril) group. After intraperitoneal injection or intragastric administration of the drugs, the tumor growth curve was determined, and the tumor tissues were also sampled to detect the expression of Ki-67, STAT3, Bax and Bcl-2 by real-time quantitative PCR and immunohistochemistry. The apoptosis was detected by TUNEL+DAPI staining. RESULTS: The tumor growth curve showed that the tumor model in the nude mice was successfully established. The tumor volumes among groups showed significantly different after 14 d growth. The increase in the tumor volume in normal control group was significantly faster than that in the other two groups, and that in positive control group was the slowest. The expression of Bax in captopril group increased, and the expression of STAT3, Ki-67 and Bcl-2 was reduced as compared with normal control group and positive control group. Compared with normal control group, the apoptotic rate increased significantly, and the protein expression of p-STAT3 and STAT3 decreased obviously in positive control group and captopril group. CONCLUSION: With better feasibility, angiotensin-converting enzyme inhibitor captopril has a significant effect on treating gastric cancer in the AGS nude mouse model by regulating the expression of STAT3, Bax, Bcl-2 and Ki-67 to accelerate the apoptosis of cancer cells, thus inhibiting tumor growth.     

Effect of biological clock gene Timeless silencing on apoptosis and invasion of ovarian cancer SKOV3 cells

AIM:To evaluate the effect of biological clock gene Timeless (TIM) silencing on the apoptosis and invasion ability of human ovarian cancer SKOV3 cells. METHODS:The protein expression of TIM in the ovarian cancer tissues and normal ovarian tissues was detected by immunohistochemistry, and the correlation between the protein expression of TIM in ovarian cancer tissues and the pathological features was analyzed. The ovarian cancer SKOV3 cells were transfected with PBS (blank control group), control siRNA (siRNA control group) or TIM siRNA (TIM siRNA group). The protein expression of TIM, Bcl-2, Bax, MMP-2, MMP-9, caspase-3 and caspase-9 was determined by Western blot. The apoptosis was detected by flow cytometry. The invasion ability was measured by Transwell chamber test. RESULTS:The positive expression rate of TIM in the ovarian cancer tissues (84.0%) was significantly higher than that in the normal ovarian tissues (10.0%; P<0.01). TIM expression was associated with ovarian cancer differentiation, depth of invasion, lymph node metastasis and TNM stage (P<0.05), but was not associated with age and pathological type (P>0.05). The protein expression levels of TIM, MMP-2, MMP-9 and Bcl-2 in TIM siRNA group were significantly decreased as compared with control group and siRNA control group (P<0.01), and the protein expression of Bax, caspase-3 and caspase-9 in TIM siRNA group was significantly increased as compared with blank control group and siRNA control group (P<0.01). No significant difference of the protein expression of TIM, MMP-2, MMP-9, Bcl-2, Bax, caspase-3 and caspase-9 between blank control group and siRNA control group was observed (P>0.05). The apoptotic rate in TIM siRNA group was significantly higher than that in blank control group and siRNA control group (P<0.01), and that in blank control group and siRNA control group was not significantly different (P>0.05). The penetrated cell number in TIM siRNA group was significantly less than that in blank control group and siRNA control group (P<0.01), and that in blank control group and siRNA control group was not significantly different (P>0.05). CONCLUSION:Silencing of TIM gene in ovarian cancer SKOV3 cells by siRNA promotes apoptosis, and inhibits cell invasion.     

Effect of ruthenium-polypyridine complex on apoptosis of gastric cancer SGC-7901 cells

AIM:To study the effect of ruthenium-pyridine complex Ru1 on apoptosis of gastric cancer SGC-7901 cells. METHODS:MTT assay and crystal violet staining method were used to detect the viability and cell number of SGC-7901 cells treatment with Ru1. Annexin V-FITC and PI staining was performed to test the apoptosis rate of SGC-7901 cells. The protein expression of Bax and Bcl-2 was detected by Western blot. RESULTS:The results of MTT assay and crystal violet staining showed that the ruthenium-pyridine complexes significantly reduced the viability and cell number of SGC-7901 cells. Treatment with Ru1 for 24 h significantly increased the apoptotic rate of SGC-7901 cells (P<0.05). Ru1 up-regulated the expression of Bax protein and down-regulated the expression of Bcl-2 protein in the SGC-7901 cells (P<0.05). CONCLUSION:Ru1 induces apoptosis of SGC-7901 cells by affecting the expression of Bax and Bcl-2 proteins.     

MicroRNA-330 inhibits growth and migration of gastric cancer cells by directly targeting EGR-2

AIM:To explore the function and significance of microRNA-330 (miR-330) in the development of gastric cancer. METHODS:Forty-eight cases of gastric cancer tissues and paired adjacent tissues were collected in Department of Oncology, Affiliated Hospital of Gansu University of Chinese Medicine, and the expression levels of miR-330 were detected by RT-qPCR. The expression levels of miR-330 in the gastric cancer cells and human gastric epithelial GES-1 cells were evaluated by RT-qPCR. The viability, colony formation and migration of gastric cancer cells after transfected with miR-330 inhibitor or miR-330 mimic were analyzed by CCK-8 assay, colony formation assay and Transwell assay, respectively. Furthermore, miR-330 target gene was predicted by miRanda target gene prediction database. RESULTS:miR-330 expression was down-regulated both in gastric cancer tissues and gastric cancer cells (P<0.05). The expression levels of miR-330 were negatively associated with the tumor size, lymph metastasis, pathological grade stage and T stage (P<0.05). The viability, colony formation and migration of gastric cancer cells were significantly increased after transfected with miR-330 inhibitor (P<0.05). However, the viability, colony formation and migration of gastric cancer cells were significantly decreased after transfected with miR-330 mimic (P<0.05). Furthermore, EGR-2 was the direct target gene of miR-330. CONCLUSION:miR-330 suppresses gastric cancer cell growth and migration, and the mechanism may be related to its direct target gene EGR-2, suggesting that miR-330 may be used as a potential new target for diagnosis and targeted therapy for gastric cancer.     

Clinical significance of miRNA-326 expression in gastric cancer and effect of up-regulation of its expression on viability and apoptosis of gastric cancer cells

AIM: To investigate the clinical significance of microRNA-326 (miRNA-326) expression in gastric carcinoma and the effect of up-regulation of its expression on the viability and apoptosis of gastric cancer cells. METHODS: The expression of miRNA-326 in 55 tissue samples of gastric cancer was detected by RT-qPCR, and the relationship between the expression and the clinicopathological features was analyzed. The expression of miRNA-326 in gastric cancer BGC-823 cells was detected by RT-qPCR. The BGC-823 cells were transfected by liposome method, and randomly divided into normal control group (untransfected), mimic-NC group (transfected with negative control mimic) and miRNA-326 mimic group (transfected with miRNA-326 mimic). After up-regulation of miRNA-326 expression, the cell viability was measured by CCK-8 assay, and the apoptosis of the cells was analyzed by flow cytometry. The protein levels of matrix metalloprotein 9 (MMP-9), p21, cyclin D1, Bcl-2 and cleaved caspase-3 were determined by Western blot, and the mRNA expression of cyclin D1 was detected by RT-qPCR. Whether CCND1 (the gene of cyclin D1) was the target gene of miRNA-326 was evaluated by dual-luciferase reporter assay. RESULTS: The expression of miRNA-326 in the gastric cancer tissues was significantly lower than that in the adjacent tissues (P<0.05). The miRNA-326 expression had a significant correlation with the tumor size, lymph node metastasis, differentiation, and clinical stages (P<0.05), but it had no correlation with the age and sex of the patients. Moreover, the expression of miRNA-326 was also closely related to the survival rate of the patients (P<0.05). The expression of miRNA-326 in the BGC-823 cells was significantly lower than that in the normal gastric mucosa GES-1 cells (P<0.05). Compared with normal control group, the expression of miRNA-326 in mimic-NC group did not change significantly, while that in miRNA-326 mimic group was increased significantly (P<0.05). Compared with normal control group, the cell viability in miRNA-326 mimic group was significantly decreased, and the apoptosis was increased (P<0.05). In addition, compared with normal control group, the protein levels of MMP-9, cyclin D1 and Bcl-2, and the mRNA expression of cyclin D1 in miRNA-326 mimic group were decreased, while the protein levels of p21 and cleaved caspase-3 were increased (P<0.05). However, no significant difference of above protein and mRNA levels between mimic-NC group and normal control group was observed. Compared with mimic-NC+miR-326 mimic group, the activity of luciferase in the cells transfected with pmiR-CCND1-WT plasmid was significantly decreased (P<0.05), but that in the cells transfected with pmiR-CCND1-Mut plasmid did not change significantly. CONCLUSION: The expression level of miRNA-326 in gastric cancer tissues is low, and it may promote cell viability and inhibit cell apoptosis by targeting CCND1.     

Expression of CUG-binding protein 1 in breast cancer and its effect on cell viability and invasion ability

AIM: To investigate the expression of CUG-binding protein 1 (CUGBP1) in breast cancer tissues, and to explore the effect of CUGBP1 gene silencing on the viability and invasion ability of human breast cancer MCF-7 cells. METHODS: A total of 96 cases of patients with breast cancer undergoing surgical treatment were selected in the Second Affiliated Hospital of Zhengzhou University from March 2015 to September 2017. Immunohistochemical staining was used to detect the protein expression of CUGBP1 in the breast cancer and adjacent tissues. MCF-7 cells were cultured and divided into CUGBP1 interference sequence group, control sequence group and blank group. Western blot was used to detect the protein expression of CUGBP1, Twist, E-cadherin and vimentin in the cells. The cell viability was measured by MTT assay. The cell invasion ability was detected by Transwell assay. RESULTS: The positive expression rate of CUGBP1 protein in the breast cancer tissues was higher than that in the adjacent tissues (χ²=28.900, P<0.001). The differences of CUGBP1 protein expression in the breast cancer tissues among TNM staging, histological grading and lymph node metastasis were statistically significant (P<0.05). The relative protein expression levels of CUGBP1, Twist and vimentin in CUGBP1 interference sequence group were lower than those in control sequence group and blank group, while the relative protein expression of E-cadherin was higher than that in control sequence group and blank group (P<0.05). The cell viability at 24 h, 48 h, 72 h and 96 h in CUGBP1 interference sequence group was lower than that in control sequence group and blank group (〖P<0.05). The invasive cells in CUGBP1 interference sequence group were less than those in control sequence group and blank group (P<0.05). CONCLUSION: CUGBP1 protein is highly expressed in the breast cancer tissues. Specific silencing of 〖STBX〗CUGBP1〖STBZ〗 gene expression in breast cancer MCF-7 cells effectively inhibits the cell viability and invasiveness, and its mechanism may be related to inhibiting the process of epithelial-mesenchymal transition.     

Pancreatic cancer cell-secreted exosomes promote apoptosis of β cells via activation of mitochondrial apoptotic pathways

AIM: To investigate the effects of exosomes secreted by pancreatic cancer cells on the viability and function of β cells and the possible mechanism. METHODS: ExoQuick-TC kit was used to extract exosomes in the supernatants of mouse pancreatic cancer Pan02 and MPC-83 cells, and the extracted exosomes were identified by transmission electron microscopy. Fluorescence-labeled exosomes were incubated with mouse insulinoma MIN6 cells for 48 h to detect whether exosomes secreted by pancreatic cancer cells were uptaken by MIN6 cells. MTT and glucose-stimulated insulin secretion (GSIS) assays were conducted to examine cell viability and insulin secretion of MIN6 cells after incubating with exosomes. The expression of miR-204 and Bcl-2 mRNA in MIN6 cells was detected by qPCR. The protein expression of Bcl-2, Bax, caspase-3 and cytochrome C (Cyt-C) in MIN6 cells was determined by Western blot. RESULTS: The results of transmission electron microscopy showed that both Pan02 cells and MPC-83 cells secreted exosomes, and Pan02 cells secreted more. The co-incubation results of fluorescence-labeled exosomes and MIN6 cells confirmed that MIN6 cells were able to ingest large amounts of exosomes secreted by pancreatic cancer cells. The results of MTT and GSIS assays showed that the viability and the level of high glucose-stimulated insulin secretion of MIN6 cells in exosome treatment group significantly decreased compared with nontreatment group (P<0.01). The results of qPCR showed that the exosomes secreted by pancreatic cancer cells were rich in miR-204, and the mRNA expression of Bcl-2 in MIN6 cells was significantly down-regulated by exosome incubation (P<0.01). The results of Western blot showed that the protein expression of Bcl-2 in the MIN6 cells treated with exosomes was significantly down-regulated (P<0.05), and the protein levels of Bax, cleaved caspase-3 and Cyt-C in exosomes treatment group were significantly up-regulated (P<0.01). CONCLUSION: Pancreatic cancer cells secrete exosomes. The exosomes secreted by pancreatic cancer cells are ingested by β cells, and reduce the viability and insulin secretion of β cells. The mechanism may be related to the increase in exosomal miR-204 in the β cells. Increasing miR-204 may inhibit the expression of Bcl-2 and promote the activation of mitochondrial apoptosis in β cells.     

Effects of all-trans retinoic acid on sensitivity of gastric cancer cells to radiotherapy

AIM: To investigate the effect of all-trans retinoic acid (ATRA) on the viability of gastric cancer cell SGC-7901 and the sensitivity to radiotherapy. METHODS: MTT assay was used to examine the cell viability. Radio-sensitivity and cell cycle were determined by colony formation assay and flow cytometry, respectively. The mRNA levels of Bax, Bcl-2, survivin and NF-κB in the cells were measured by RT-qPCR. RESULTS: ATRA inhibited the viability of SGC-7901 cells in a concentration-dependent manner. The maximal inhibition was at concentration of 8 μmol/L. Colony formation assay revealed that the combination of ATRA with X-ray treatment significantly reduced the values of D0 and Dq, and shifted down the fitting survival curve, as compared with radiotherapy alone. Moreover, ATAR markedly decreased the percentage of G₂/M phase in the SGC-7901 cells (P<0.05). In addition, following ATRA treatment, the mRNA levels of Bcl-2 and survivin were decreased (P<0.05), whereas the mRNA levels of Bax and NF-κB were increased (P<0.05). CONCLUSION: ATRA enhances the sensitivity of SGC-7901 cells to radiotherapy, inhibits G₂/M arrest and regulates the mRNA expression of Bax, Bcl-2, survivin and NF-κB.     

Expression of miR-625-3p in colorectal carcinoma tissues and cells

AIM: To investigate the expression of microRNA-625-3p (miR-625-3p) in colorectal carcinoma (CRC) and its underlying mechanism. METHODS: Quantitative real-time PCR was employed to detect the levels of miR-625-3p expression in different CRC cell lines, CRC tissues and pair-matched adjacent normal tissues. The relationships between the expression levels of miR-625-3p and the patients' clinicopathological parameters were estimated. The effects of miR-625-3p on the apoptosis and the cell mitotic cycle of CRC cells were analyzed with propidium iodide staining and flow cytometry. The effect of miR-625-3p on the apoptosis-related proteins was analyzed by Western blot. RESULTS: The expression level of miR-625-3p in the CRC tissues was higher than that in the pair-matched adjacent normal tissues (P<0.05). The expression of miR-625-3p in the CRC tumor tissues was significantly correlated with the tumor infiltrative depth, TNM stage and distant metastasis (P<0.05). The expression levels of miR-625-3p in CRC SW620 cells were higher than that in SW480 cells. The CRC cell mitotic cycle was significantly inhibited and cell apoptosis was significantly promoted when the expression of miR-625-3p was inhibited (P<0.05). The expression of Bax protein didn't change and the expression of Bcl-2 protein increased after miR-625-3p mimics were transfected into CRC SW620 cells(P<0.05). CONCLUSION: miR-625-3p may be a promising approach for the treatment of CRC by promoting cell proliferation and inhibiting apoptosis.     

Fucoidan sulfate promotes apoptosis of gastric cancer cells by regulating expression of HDAC1

AIM:To study the effects of fucoidan sulfate on the apoptosis of gastric cancer cells, and to explore its relationship with histone deacetylase 1 (HDAC1). METHODS:The effects of fucoidan sulfate on the viability of gastric cancer BGC-823 cells were measured by MTT assay. The cells were divided into si-HDAC1 group, si-NC group and fucoidan+pcDNA 3.1-HDAC1 group and fucoidan+pcDNA 3.1 group. The transfection were performed by liposome method. The apoptosis was analyzed by flow cytometry. The protein expression of HDAC1, Bcl-2 and Bax was determined by Western blot. The mRNA expression of HDAC1 was detected by RT-qPCR. RESULTS:Compared with the control cells, the inhibitory rates of the cell viability by fucoidan sulfate (0.2, 0.4, 0.6, 0.8 and 1.0 g/L) were increased signi-ficantly (P<0.05). The appropriate concentration was 0.6 g/L. Compared with control group, the expression of HDAC1 at mRNA and protein levels in fucoidan sulfate group was significantly down-regulated, while the apoptotic rate was significantly increased (P<0.05). Knock-down of HDAC1 expression significantly up-regulated the apoptotic rate, while over-expression of HDAC1 reversed the apoptosis-promoting effect of fucoidan sulfate on the BGC-823 cells. CONCLUSION:Fucoidan sulfate promotes apoptosis of gastric cancer cells. The mechanism may be related to the direct inhibition of HDAC1, which provides support for the clinical application of fucoidan sulfate.     

Effects of CARHSP1 gene expression on viability,apoptosis and immune factors of vascular endothe-lial cells induced by hypoxia in atherosclerosis

AIM: To investigate the effect of calcium-regulated heat stable protein 1 (CARHSP1) gene expression on the viability, apoptosis and expression of interleukin-6 (IL-6) and C-reactive protein (CRP) in vascular endothe-lial cells induced by hypoxia.METHODS: The protein expression of CARHSP1 was detected by Western blot in atherosclerotic plaques. Human umbilical vein endothelial cells (HUVECs) were treated with hypoxia, and the cells were divided into normal culture group, hypoxia group, hypoxia+CARHSP1-siRNA group and hypoxia+pcDNA3.1-CARHSP1 group. The viability and apoptotic rate of the HUVECs were measured by CCK-8 assay and flow cytometry, respectively. The mRNA expression of IL-6 and CRP was detected by RT-PCR. The protein levels of caspase-3, cleaved caspase-3, Bcl-2 and Bax were determined by Western blot.RESULTS: The protein expression of CARHSP1 in atherosclerotic plaques was significantly higher than that in control group (P<0.05). Hypoxia significantly increased the expression of CARHSP1. The cell viability and the protein expression of Bcl-2 were significantly lower in hypoxia group than those in normal culture group (P<0.05). The apoptotic rate and the protein levels of IL-6, CRP, cleaved caspase-3 and Bax were significantly higher than those in normal culture group (P<0.05). Compared with hypoxia group, the cell viability and protein expression of Bcl-2 were significantly increased in hypoxia+CARHSP1-siRNA group, while the apoptotic rate and the protein levels of IL-6, CRP, cleaved caspase-3 and Bax were decreased significantly (P<0.05). The cell viability and protein expression of Bcl-2 were decreased significantly in hypoxia+pcDNA3.1-CARHSP1 group, while the apoptotic rate and the protein le-vels of IL-6, CRP, cleaved caspase-3 and Bax were increased significantly (P<0.05).CONCLUSION: The expression of CARHSP1 is increased in atherosclerotic plaques, and inhibition of CARHSP1 expression improves the viability, reduces the apoptosis, and down-regulates the expression of IL-6 and CRP in the HUVECs. Over-expression of CARHSP1 exerts the opposite effect.     

Effects of USP9X down-regulation on apoptosis and invasion ability of gastric carcinoma AGS cells

AIM: To investigate the effects of ubiquitin-specific peptidase 9, X-linked (USP9X) down-regulation on apoptosis and invasion ability in gastric carcinoma cells, and to explore its possible molecular mechanisms. METHODS: USP9X small interfering RNA (siRNA) and control siRNA were used to be transfected into gastric carcinoma AGS cells. The cells were divided into 3 groups, including untreated AGS group, control siRNA group and USP9X siRNA group. The expression of USP9X at mRNA and protein levels in the AGS cells with different treatments was determined by real-time PCR and Western blot. The cell viability was analyzed by CCK-8 assay. Flow cytometry and Boyden chamber were employed to examine the apoptosis and invasion ability of the AGS cells. RESULTS: USP9X siRNA significantly down-regulated the expression of USP9X at mRNA and protein levels in the AGS cells. Down-regulation of USP9X markedly induced apoptosis and reduced invasion ability of the gastric carcinoma AGS cells. Notably, down-regulation of USP9X significantly reduced the protein expression of Mcl-1 and MMP-2, but markedly increased the protein level of Bax. CONCLUSION: USP9X may be a key regulator for apoptosis and invasion in gastric carcinoma.     

Apelin-13 inhibits nicotine-induced apoptosis of H9c2 cells via PI3K/Akt signaling pathway

AIM:To investigate the effect of apelin-13 on nicotine-induced apoptosis of cardiomyocytes and its potential molecular mechanism. METHODS:Rat H9c2 cells were treated with nicotine (10 μmol/L) to induced apoptosis. Flow cytometry was used to detect apoptotic rate. Western blot was used to determined the expression of related proteins. RESULTS:Compared with control group, nicotine treatment significantly increased the apoptotic rate of the H9c2 cells (P<0.01), and the protein levels of apoptosis-related proteins Bax and cleaved caspase-3, but markedly decreased the protein levels of Bcl-2, p-Akt, p-PI3K and APJ (P<0.05). Compared with nicotine group, apelin-13+nicotine significantly decreased the apoptotic rate of the H9c2 cells (P<0.01) and the the protein levels of Bax and cleaved caspase-3, but markedly increased the protein levels of Bcl-2, p-Akt, p-PI3K and APJ (P<0.05). Compared with apelin-13+nicotine group, apelin-13+nicotine+PI3K/Akt inhibitor LY294002 significantly increased the apoptotic rate of the H9c2 cells (P<0.01) and the protein levels of Bax and cleaved caspase-3, but markedly decreased the protein levels of Bcl-2, p-Akt and p-PI3K (P<0.05). CONCLUSION:Apelin-13 inhibits nicotine-induced apoptosis of H9c2 cells through PI3K/Akt signaling pathway.     

Effects of adenovirus-mediated shRNA targeting PTEN on proliferation and apoptosis of activated hepatic stellate cells in vitro

AIM:To investigate the down-regulation of phosphatase and tensin homolog deleted on chromosome 10(PTEN) gene by adenovirus-mediated short hairpin RNA(shRNA) on proliferation and apoptosis of activated hepatic stellate cells(HSCs) in vitro and the related signaling transduction pathways. METHODS:The activated HSCs were cultured in vitro and transfected with recombinant adenovirus expressing shRNA targeting PTEN. The proliferation of HSCs was measured by MTT assay and the apoptosis was assessed by TUNEL and flow cytometry. Western blotting was used to detect the protein levels of PTEN, Bax, Bcl-2, Akt, p-Akt, ERK1/2 and p-ERK1/2 in HSCs, and real-time fluorescent quantitative PCR was applied to detect the mRNA expression of Akt and ERK1. RESULTS:The recombinant adenovirus expressing shRNA targeting PTEN was successfully transfected into activated HSCs in vitro, and significantly promoted the proliferation of HSCs in a time-dependent manner within a certain extent. The apoptotic rate of HSCs was significantly decreased 72 h after transfection(P<0.05). Meanwhile, reduced expression of Bax and elevated expression of Bcl-2 were induced 72 h after transfection(P<0.05). Furthermore, the expression of p-Akt and p-ERK1/2 were increased significantly(P<0.05), while no significant difference in the expression of Akt and ERK1 at mRNA and protein levels was observed(P>0.05). CONCLUSION:Down-regulation of PTEN by adenovirus-mediated shRNA dramatically promotes the proliferation of activated HSCs, and inhibits the apoptosis through Bcl-2/Bax pathway. In addition, the phosphorylation of Akt and ERK1/2 is increased, indicating that PI3K/Akt and ERK1/2 signal transduction pathways may play an important role in the regulation of proliferation and apoptosis of HSCs.     

Protective effects of Zhouluotong extract Z-6 on Schwann cells damaged by high-glucose and PI3K/Akt/nNOS pathway

AIM:To explore the role of PI3K/Akt/nNOS in Zhouluotong extract resisting diabetic peripheral neuropathy. METHODS:The Schwann cells were divided into normal group (D-glucose 25 mmol/L), model group (D-glucose 100 mmol/L), Zhouluotong extract Z-6 + high glucose group, Zhouluotong + high glucose group, mecobalamine + high glucose group. The viability, nitric oxide content and the Ca2+-ATPase activity in Schwann cells were determined by Cell Counting Kit-8 , nitric oxide assay kit and Ca2+-ATPase assay kit, respectively. The apoptosis of Schwann cells were analyzed by flow cytometry. The expression of Bcl-2, Bcl-xL, Bax, Bak and caspase-3, and the phosphorylation levels of nNOS and Akt were determined by Western blotting. The signal pathway of PI3K/Akt was explored by dominant negative PI3K and Akt (δp85 and DN-Akt) transient transfection assay. RESULTS:Under high-glucose culture, the cell viability, nitric oxide content in culture supernatant, the expression of Bcl-2 and Bcl-xL, and the phosphorylation levels of Akt and nNOS in the Schwann cells were significantly increased. The cell apoptosis, the expression of Bax, Bak and caspase 3 in the Schwann cells were significantly decreased by Zhouluotong extract Z-6, compared with model group. Increased nitric oxide content and the up-regulation of nNOS were observed. However, the effects of blocking PI3K/Akt, the upstream pathway of nNOS , by transfection with DN-δp85 on Akt phosphorylation in the Schwann cells was still unclear. CONCLUSION: Zhouluotong extract Z-6 changes the phosphorylation of nNOS, and the expression of anti-apoptotic factors, caspase-3 and pro-apoptotic factors in Schwann cells under high-glucose culture, thus reducing apoptosis and elevating viability. The relationship to PI3K/Akt/nNOS pathway needs further investigation.     

Clinical significance of STMN1 expression in cervical cancer and effect of inhibition of its expression on viability and apoptosis of cervical cancer SiHa cells

AIM: To investigate the clinical significance of stathmin 1 (STMN1) expression in cervical cancer and the influence of its expression on the viability and apoptosis of cervical cancer cells. METHODS: Western blot was used to detect the protein expression of STMN1 in cervical cancer tissues, and the relationship between the expression and clinical characteristics of cervical cancer was analyzed. STMN1-siRNA was transfected into cervical squamous-cell carcinoma SiHa cells. The protein levels of STMN1, STAT3, p-STAT3 and survivin were determined by Western blot after transfection for 48 h. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. DCFH-DA probe was used to detect the level of reactive oxygen species (ROS). RESULTS: The protein expression of STMN1 in cervical cancer tissues was significantly higher than that in paracancerous tissues (P<0.01). The STMN1 protein expression level was not correlated with age and histological types of cervical cancer patients, but was related to clinical stage, histological differentiation and lymph node metastasis (P<0.01). Transfection with STMN1-siRNA significantly reduced the expression of STMN1 in SiHa cells. Compared with control group, the cell viability in STMN1-siRNA group was significantly decreased, the apoptotic rate and ROS content were increased, and the protein levels of p-STAT3 and survivin were down-regulated (P<0.01). However, no significant difference of the STAT3 protein level was observed between STMN1-siRNA group and control group. CONCLUSION: STMN1 is highly expressed in cervical cancer, and its expression is related to clinical stage, histological differentiation and lymph node metastasis. Inhibition of STMN1 expression reduces the viability and promotes apoptosis of cancer cells by down-regulating STAT3 signaling pathway.