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.     

Protective effect of all-trans retinoic acid pretreatment against rat intestinal injury induced by hepatic inflow occlusion

AIM：To investigate the effect of all-trans retinoic acid (ATRA) on the intestinal injury induced by hepatic inflow occlusion (HIO) and its mechanisms. METHODS：Thirty-two male Sprague-Dawley rats were randomly divided into four groups: sham group, HIO group, dimethyl sulfoxide (DMSO) + HIO group and ATRA (15 mg·kg-1·d-1) + HIO group. The hepatoduodenal ligament of the rats in the latter three groups was occluded (Pringle manoeuvre) by clamp for 30 min. After reperfusion for 2 h by release of the clamp, samples of distal ileum and serum were collected. Histological changes and Chiu’s scores of the ileac mucosa were evaluated under light microscope. Serum content of diamine oxidase (DAO), and ileac tissue levels of malonaldehyde (MDA) and superoxide dismutase (SOD) were analyzed by colorimetry. Serum concentrations of interleukin (IL)-1β and tumor necrosis factor (TNF)-α were evaluated by enzyme-linked immunosorbent assay method. Expression of manganese superoxide dismutase (MnSOD) in cytoplasm and nuclear factor kappa B (NF-κB) p65 in nucleus was assessed by Western blotting. RESULTS：Compared with sham group and DMSO+HIO group, ATRA significantly reduced the mucosal Chiu’s scores, the serum content of DAO and the tissue level of MDA, enhanced the serum activity of SOD and the protein expression of MnSOD, and decreased the content of NF-κB p65 in nucleus (all P<0.05). Subsequently, ATRA significantly reduced the levels of TNF-α and IL-1β in serum (P<0.05). CONCLUSION：ATRA can attenuate rat intestinal injury induced by HIO through improving the antioxidant capacity of tissue, inhibiting the activation of NF-κB and suppressing the overexpression of pro-inflammatory factors.     

MicroRNA-146a promotes apoptosis of gastric cancer SGC-7901 cells by targeting TAK1

AIM: To explore the effect of microRNA-146a (miR-146a) on apoptosis of human gastric cancer SGC-7901 cells and the underluing mechanism. METHODS: miR-146a mimic (up-regulated miR-146a expression) and miR-146a inhibitor (down-regulated miR-146a expression) were transfected into the SGC-7901 cells by liposome method. At the same time, miRNA nonsense sequence transfection group as the negative control group (NC group) was set up. RT-qPCR was used to evaluate the levels of miR-146a in the SGC-7901 cells after transfection. The effects of miR-146a on the cell apoptosis and growth were assessed by flow cytometry analysis and CCK-8 assay, respectively. The effect of over-expression or knockdown of miR-146a on transforming growth factor-β-activated kinase 1 (TAK1)/nuclear factor-kappa B (NF-κB) signaling was evaluated by RT-qPCR and Western blot. RESULTS: miR-146a modulated apoptosis of SGC-7901 cells. Over-expression of miR-146a significantly increased apoptosis, whereas knockdown of miR-146a inhibited the apoptosis of SGC-7901 cells. The expression of TAK1 at mRNA and protein levels was significantly decreased when miR-146a mimic was transfected into the SGC-7901 cells (P<0.05). On the contrast, the expression of TAK1 at mRNA and protein were significantly higher in miR-146a inhibitor transfection group than that in NC group (P<0.05), suggesting that miR-146a negatively regulated TAK1 expression. Moreover, knockdown of TAK1 enhanced the apoptosis of SGC-7901 cells (P<0.01), while over-expression of TAK1 inhibited the apoptosis of SGC-7901 cells(P<0.01). Additionally, both over-expression of miR-146a and knockdown of TAK1 led to a prominent increase in the expression of NF-κB inhibitor protein alpha (IκBα) and a significat decrease in B cell lymphoma-2 (Bcl-2) level in the SGC-7901 cells. CONCLUSION: miR-146a significantly promotes apoptosis of SGC-7901 cells by inhibition of NF-κB pathway via targeting TAK1.     

Double TdR blocking induces synchronization of cell cycle in human gastric cancer SGC-7901 cells

AIM: To investigate the effects of double thymidine deoxyribonucleoside (TdR) blocking on the cell cycle of human gastric cancer SGC-7901 cells.METHODS: SGC-7901 cells in the logarithm period were selected in the study and treated with TdR at concentration of 2 mmol/L, 4 mmol/L or 8 mmol/L for 15 h as the first blocking. After incubation in TdR-free medium for 10 h, the cells were treated with TdR at same concentrations again for another 15 h as the second blocking. The blocked cells were released by washing in fresh medium twice and incubation in TdR-free medium containing 10% fetal bovine serum for 12 h. The cells were collected and the cell cycle was detected by flow cytometry.RESULTS: By double TdR (2 mmol/L, 4 mmol/L and 8 mmol/L) blocking to synchronize the cell cycle, the cells in G₀/G₁ phase accounted for 77.3%, 77.5% and 77.0%, respectively. After further incubation for 12 h in TdR-free medium, the proportion of the cells in each phase of the cell cycles returned to normal range. CONCLUSION: The method of double TdR blocking is an ideal access in short term to acquire a large number of cells in G₀/G₁ phase.     

Inhibitory effect of ampelopsin combined with mitomycin on proliferation of gastric carcinoma cells

AIM: To investigate the synergistic effects of ampelopsin (AMP) and a chemotherapeutic drug mitomycin (MMC) on the proliferation of gastric cancer cell line SGC-7901.METHODS: SGC-7901 cells were cultured in vitro and divided into 4 groups: control group, AMP group, MMC group and AMP+MMC group. Cell proliferation was measured by MTT method. The apoptotic index was examined by flow cytometry. The expression of apoptotic proteins, Bcl-2 and survivin, was detected by Western blotting.RESULTS: AMP at the concentrations ranging from 2.2 mg/L to 14.84 mg/L exerted inhibitory effect on the growth of SGC-7901 cells. Cell proliferation in AMP (14.84 mg/L) group was inhibitory by (60.85±1.13) %, significantly higher than that in control group (P<0.05). The inhibitory rates of cell proliferation varied from (17.40±0.30) % to (72.23±1.36) % when the concentrations of MMC increased from 1×10^-3 g/L to 1×10^-2 g/L. AMP combined with MMC showed a synergistic effect on the growth of SGC-7901 cells. The inhibitory rates of cell proliferation varied from (21.83±2.50) % to (46.70±1.45) % when the concentrations of MMC increased from 1×10^-3g/L to 5×10^-3g/L. The inhibitory effect of AMP plus MMC was higher than that of MMC or AMP alone. The protein levels of Bcl-2 and survivin were inhibited in AMP group, MMC group and AMP+MMC group, and were significantly lower in AMP+MMC group than those in AMP group or MMC group.CONCLUSION: AMP enhances the inhibitory effect of MMC on the growth of SGC-7901 cells. The mechanism is related to the inhibition of apoptotic protein expression.     

Effects of RARG on viability and migration ability of gastric cancer cells

AIM:To investigate the effect of retinoic acid receptor gamma (RARG) on the viability and migration ability of gastric cancer cells. METHODS:The expression of RARG in gastric cancer and normal gastric tissues and its correlation with the overall survival rate of gastric cancer patients were analyzed by bioinformatics. The expression of RARG was promoted and inhibited by over-expression plasmid transfection and RNA interference technique in gastric can-cer cells in vitro, respectively. MTT and Transwell assays were used to detect the effect of RARG on the viability and migration ability of gastric cancer cells. The effect of RARG on regulating the Wnt/β-catenin signaling pathway was evaluated by Western blot and TOP/FOP dual-luciferase reporter assay. The protein interaction of RARG and β-catenin was determined by co-immunoprecipitation and immunofluorescence co-localization assay. RESULTS:Over-expression of RARG enhanced the viability and migration ability of gastric cancer SGC7901 cells (P<0.05). Knockdown of RARG attenuated the viability and migration ability of gastric cancer MGC-803 cells (P<0.05). At the same time, RARG over-expression increased the protein expression levels of β-catenin, c-Myc, cyclin D1, Twist and Snail (P<0.05), and the activity of TOP/FOP dual-luciferase reporter gene (P<0.05). In addition, RARG interacted with β-catenin protein in the gastric cancer cells. CONCLUSION:RARG promotes the viability and migration ability of gastric cancer cells via activating the Wnt/β-catenin signaling pathway, thus playing an important role in the development of gastric cancer.     

Effect of over-expression of transcription factor CDX2 on proliferation and cell cycle of human gastric cancer cell line SGC-7901

AIM: To study the effect and the molecular mechanism of CDX2 over-expression on the proliferation, growth and cell cycle of human gastric cancer cell line SGC-7901. METHODS: The SGC-7901 cells in LV-CDX2-GFP group were transfected with the recombinant lentivirus vector LV-CDX2-GFP, the cells in LV-GFP group were transfected with the negative control lentiviral vector for the negative control, and the cells in blank control group were without any treatment. The cell proliferation was detected by CCK-8 assay. The cell cycle distribution was analyzed by flow cytometry. The expression of CDX2, Bax, Bcl-2, cyclin D1 and survivin was determined by semi-quantitative RT-PCR and Wes-tern blotting. RESULTS: Compared with LV-GFP group and blank control group, the proliferation activity of the SGC-7901 cells was significantly lower (P<0.05), the G0/G1 phase proportion increased (P<0.05), the mRNA and protein levels of Bcl-2, cyclin D1 and survivin were reduced (P<0.05), and the mRNA and protein levels of Bax were up-regulated (P<0.05) in LV-CDX2-GFP group. No statistically significant difference of the above indexes was observed (P>0.05) between LV-GFP group and blank control group. CONCLUSION: Over-expression of CDX2 mediated by lentivirus inhibits the proliferation and growth of human gastric cancer SGC-7901 cells and arrestes the cell cycle at G0/G1 phase, which may be related to down-regulation of Bcl-2, cyclin D1 and survivin and up-regulation of Bax.     

Effects of GOLPH3 gene silencing mediated by lentivirus on proliferation,invasion and metastasis of human gastric cancer cell line SGC-7901

AIM：To investigate the effect of Golgi phosphoprotein 3 (GOLPH3) gene silencing on the proliferation, invasion and metastasis of human gastric cancer SGC-7901 cell in vitro. METHODS：SGC-7901 cells were transfected with lentiviral vector carrying GOLPH3 shRNA to construct a stable GOLPH3-silencing cell line LV-GOLPH3-RNAi. The expression of GOLPH3 at mRNA and protein levelss were detected by real-time PCR and Western blotting, respectively. The cell proliferation was analyzed by MTT assay. Transwell migration and invasion experiments were performed to measure the migration and invasion abilities, respectively. RESULTS：The stable GOLPH3-silencing cell line was successfully established. The expression of GOLPH3 at mRNA and protein levels was reduced significantly (P<0.05), leading to the inhibition of cell proliferation in LV-GOLPH3-RNAi group compared with scrambled group and blank control group, as well as the capacities of migration (56.7±1.5 vs 186.0±3.4 and 183.3±4.2, P<0.05) and invasion (33.5±3.0 vs 85.0±3.9 and 83.1±4.4, P<0.05). CONCLUSION：GOLPH3 silencing suppresses the capacities of proliferation, migration and invasion of human gastric cancer SGC-7901 cells, suggesting that GOLPH3 may be a potential tumor marker and independent prognostic factor.     

Effects of β3Gn-T8 on proliferation of gastric cancer AGS cells

AIM: To study the effects of β1,3-N-acetylglucosaminyltransferase 8 (β3Gn-T8) on the biological behaviors of gastric cancer cells and xenograft tumors. METHODS: After pEGFP-C1-β3Gn-T8 was transfected into human gastric adenocarcinoma AGS cells, the cell proliferation was measured by MTT assay and viable cell counting with trypan blue exclusion, and the apoptotic rate was analyzed by flow cytometry. The model of AGS cell subcutaneous xenograft was established to detect the growth of the xenograft. RESULTS: The proliferation of AGS cells transfected with pEGFP-C1-β3Gn-T8 was significantly increased (P < 0.05), but the apoptotic rate was not significantly changed. The growth rate and final volume of xenograft tumor in pEGFP-C1-β3Gn-T8 group were significantly higher than those in control group (P < 0.05). CONCLUSION: β3Gn-T8 promotes the proliferation of gastric cancer AGS cells and significantly increases the growth of AGS cell xenograft tumor.     

Inhibitory effect of all-trans retinoic acid on proliferation of microvascular endothelial cells

AIM: To evaluate the effects of all-trans retinoic acid (atRA) on the proliferation in cultured mouse cerebral microvascular endothelial cells (bEnd.3). METHODS: Cultured cells were divided into five groups randomly, one as control group, the other four groups were 10-9, 10-8, 10-7 and 10-6 mol/L group. Effects of atRA on proliferation in bEnd.3 cells were detected by flow cytometry and immunocytochemitry of PCNA and MTT at 24 h, 48 h and 72 h. The effects of atRA (10-6 mol/L group) on the expressions of angiogenic genes in bEnd.3 cells were studied using microarray. RESULTS: The results of MTT and flow cytometry showed that all-trans retinoic acid at concentration of 10-6 mol/L significantly inhibited the proliferation of bEnd.3 cells. Immunocytochemical staining showed the expression of PCNA was markedly decreased in bEnd.3 cells at 24 h after treatment with atRA. Microarray results demonstrated that there were 11 down-regulated angiogenic genes and 2 up-regulated angiogenic genes in 10-6mol/L atRA group. CONCLUSION: All-trans retinoic acid at concentration of 10-6mol/L may significantly inhibit the proliferation of bEnd.3 cells treated for 24 h in vitro via down-regulation of angiogenic genes and PCNA expression.     

Effects of propofol on invasion and migration of human gastric cancer SGC-7901 cells

AIM: To investigate the effects of propofol on invasion and migration of gastric cancer cell line SGC-7901. METHODS: Cultured gastric cancer cell line SGC-7901 was randomly divided into 4 groups, and then diffe-rent concentrations (1, 3, 5 and 7 mg/L) of propofol were added and incubated for 24 h. The cell viability was measured by MTT assay. The invasion and migration abilities of the SGC-7901 cells were detected by Transwell assay and wound-healing assay. The expression of cysteine-rich angiogenic inducer 61 (CYR61), CD44v6 and matrix metalloproteinase-7 (MMP-7) in the SGC-7901 cells were examined by immunocytochemistry and Western blot.RESULTS: Propofol at 5 mg/L does not affect the viability of SGC-7901 cells, whereas significantly suppresses the invasion and migration abilities, and down-regulates the expression of CD44v6 and MMP-7 (P<0.05). CONCLUSION: The decreased invasion and migration abilities of SGC-7901 cells were partly due to the inhibition of CD44v6 and MMP-7 expression.     

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.     

All-trans retinoic acid attenuates blood-brain barrier injury induced by cerebral ischemia-reperfusion in rats through JNK/P38 MAPK signaling pathway

AIM: To investigate the effect of all-trans retinoic acid (ATRA) on blood-brain barrier after cerebral ischemia-reperfusion (CIR) injury in rats and its possible role mechanism.METHODS: Male SD rats were randomly divided into sham group, model (CIR) group and CIR+ATRA (10, 30 and 90 mg/kg) groups. The rat model of CIR injury was established by MCAO thread occlusion method. After ischemia for 1.5 h and reperfusion for 24 h, the neurological functional behavioral score, cerebral infarction volume, brain water content and Evans blue content were determined. The activity of matrix metalloprotein-9 (MMP-9) was measured by gelatin zymography. The protein levels of claudin-5, occludin, ZO-1, JNK, p-JNK, P38, p-P38 and MMP-9 in the brain tissues were determined by Western blot.RESULTS: Compared with CIR model group, ATRA at 30 mg/kg significantly improved neurological function, and decreased cerebral infarction volume, brain water content, Evans blue content and the degradation of tight junction proteins in ischemic area (P<0.01). The activity and protein expression of MMP-9 in ischemic brain tissue were decreased (P<0.01). The phosphorylation of JNK and P38 was inhibited and the protein levels of p-JNK and p-P38 were decreased (P<0.01).CONCLUSION: ATRA reduces the damage of brain tissue and the destruction of blood-brain barrier induced by CIR in rats. The protective effect may be related to inhibiting the activation of JNK/P38 MAPK signaling pathway and MMP-9.     

Tanshinone IIA inhibits doxorubicin resistance in gastric cancer cells

AIM: To investigate the inhibitory effect and the specific mechanism of tanshinone IIA on doxorubicin (DOX)-resistant gastric cancer cells. METHODS: The sensitivity of gastric cancer cells lines to DOX was determined by MTT assay. DOX-resistant gastric cancer cell lines were established by step selection with increasing concentrations of DOX. The cell cycle arrest, apoptosis and autophagy related-markers were analyzed by flow cytometry and Western blot. The expression of P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multi-drug resistance-associated protein 1 (MRP-1) was determined by RT-qPCR and Western blot. RESULTS: DOX-sensitive cell lines SNU-719 and SNU-601 as well as the cell lines relatively resistant to DOX including SNU-638, SNU-668, SNU-216 and SNU-620 were identified according to the IC₅₀ values of DOX for different cell lines. Two DOX-resistant cell lines SNU-719R and SNU-601R were also established. Tanshinone IIA inhibited the expression of MRP-1 in DOX-resistant cell lines. Compared with DOX treatment alone group, combined treatment of DOX and tanshinone IIA in cancer cells decreased the G₂/M phase cell number, increased the protein expression of p21, decreased the protein expressions of cyclin B1 and cyclin-dependent kinase 1 (CDK1) in the SNU-719 R cells and SNU-620 cells. In addition, compared with DOX treatment alone group, combined treatment of DOX and tanshinone IIA in the cancer cells increased the protein expressions of p53, Bax and LC3B-II, decreased the protein expression of Bcl-2 and p62 (P<0.05). CONCLUSION: Tanshinone IIA is an effective drug in the inhibition of DOX resistance in gastric cancer.     

Baicalein inhibits proliferation and migration of gastric cancer MGC-803 cells

AIM: To investigate the effects of baicalein (BAI) on the proliferation and migration of gastric cancer MGC-803 cells and the mechanisms. METHODS: After MGC-803 cells were treated with BAI at different concentrations, the viability of the MGC-803 cells was tested by MTT assay. The cell colony formation ability were detected by plate colony formation assay. Wound-healing and Transwell cell migration assays were used to test the migration ability of the MGC-803 cells. The concentration of 12-hydroxyeicosatetraenoic acid (12-HETE) was measured by ELISA. The protein levels of platelet type 12-lipoxygenase (p12-LOX), vascular endothelial growth factor (VEGF), p-ezrin and epithelial-mesenchymal transition (EMT) markers in MGC-803 cells were determined by Western blot. RESULTS: BAI significantly inhibited the proliferation, plate colony formation and migration abilities of the MGC-803 cells (P<0.05 or P<0.01), down-regulated the concentration of p12-LOX metabolite 12-HETE significantly (P<0.05 or P<0.01), decreased the protein levels of p12-LOX, VEGF, p-ezrin, vimentin and Snail (P<0.05 or P<0.01), and increased the protein expression of E-cadherin (P<0.01). CONCLUSION: BAI suppresses the proliferation and migration abilities of gastric cancer MGC-803 cells effectively. These effects of BAI may be related to regulating the protein levels of p12-LOX, VEGF, p-ezrin and EMT-related proteins.     

Effect of beclin-1 gene silencing on TuAKe-injured gastric cancer SGC-7901 cells

AIM: To observe the effect of beclin-1 silencing by the technique of RNA interference on the injury of human gastric cancer SGC-7901 cell by Sheliugu extract (the extract from tuber of Amorphophallus konjac, TuAKe). METHODS: To knock down the expression of beclin-1 gene, SGC-7901 cells were transfected with lentiviral vector carrying beclin-1-shRNA. The beclin-1 gene knock-down and non-knock-down SGC-7901 cells were treated with TuAKe. The cell viability was analyzed by CKK-8 assay. The percentages of apoptotic cells were detected by flow cytometry. The expression of beclin-1 and LC3 was detected by Western blot. RESULTS: The beclin-1 gene silencing decreased the protein expression of beclin-1 and increased the protein expression of LC3 in the SGC-7901 cells, leading to the decrease in cell viability and the increase in apoptotic rate (P<0.05). TuAKe increased the protein expression of beclin-1 and LC3 in the SGC-7901 cells, and decreased the protein expression of LC3 in the SGC-7901 cells with beclin-1 gene silencing, thus inhibiting the cell viability and increasing the apoptotic rate (P<0.05). CONCLUSION: Beclin-1 gene silencing inhibits the activation of beclin-1-related signaling pathway in gastric cancer SGC-7901 cells, and aggravates the injury of cell viability induced by TuAKe.     

Effects of cyclooxygenase-2 inhibitors on gastric epithelial cell proliferating and gastric healing following hydrochloric acid-induced injury in rats

AIM: To clarify the effects of specific and non-specific cyclooxygenase-2 (COX-2) inhibitors on gastric epithelial cell proliferating and gastric healing following acid-induced damage. METHODS: Male Sprague-Dawley rats were given 1 mL of 0.6 mol/L hydrochloric acid (HCl) into the stomach. Ten minutes after the administration of the acid, the animals were given NS-398 (COX-2 inhibitor) or indomethacin. Levels of COX-1 and COX-2 in the gastric mucosa before and after HCl-administration were analyzed using western blotting and immunohistochemical staining. Proliferating cell nuclear antigen (PCNA) was detected using immunohistochemistry for epithelial cell proliferation. Gastric lesion index (LI) was assessed using planimetry. RESULTS: Expression of COX-2 was enhanced mainly in surface epithelial cells and neck cells following HCl-administration. At 24 h following acid administration, PCNA labeling index (PCNA-LI) was (22.72±4.33) % and (21.98±5.18) % in the groups treated with 40 mg/kg of NS-398 and indomethacin respectively, which was significantly lower than that in the control group [ (34.46±3.61) %, P< 0.05 ]; LI was (1.28±0.58) % and (1.16±0.56) % in the groups treated with 4 mg/kg and 40 mg/kg of NS-398, respectively, which was significantly higher than that in the control group [ (0.58±0.24) %, P< 0.05 ]. CONCLUSIONS: The present study demonstrated that cyclooxygenase-2 inhibitors delayed gastric mucosal healing by suppressing expansion of the mucosal proliferative zone. These results provide evidence that cyclooxygenase-2 plays an important role in gastric mucosal regeneration.     

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.     

MicroRNA-9 inhibits epithelial-mesenchymal transition in gastric cancer SGC-7901 cells by NRP1

AIM:To investigate the inhibitory effect of microRNA-9(miR-9) on epithelial-mesenchymal transition (EMT) in the gastric cancer SGC-7901 cells and its mechanism.METHODS:The gastric cancer cell line SGC-7901 was transfected with miR-9 mimics or negative control mimic (NCM),as miR-9 or NCM group,respectively.The SGC-7901 cells without transfection were used as control group.The expression level of miR-9 in each group was detected by RT-qPCR.The migration and invasion abilities of the SGC-7901 cells in the 3 groups were detected by Transwell assay.The protein expression of N-cadherin,E-cadherin,α-catenin and neuropilin-1(NRP1) was determined by Western blot.Antagonistic effect of NRP1 over-expression on miR-9 inhibition of EMT was detected by Western blot.The relationship between miR-9 and NRP1 was analyzed by dual luciferase assay.RESULTS:The expression level of miR-9 in miR-9 group was significantly up-regulated,which was 538 times higher than that in control group (P<0.05).The number of migratory cells in miR-9 group was significantly lower than that in control group (P<0.05).Compared with control group,the protein expression of N-cadherin and NRP1 in miR-9 group was significantly decreased,while the protein expression of E-cadherin and α-catenin protein was significantly increased.Over-expression of NRP1 resulted in the increase in the protein expression of N-cadherin in the gastric cancer cells of miR-9 group,and the decrease in the protein expression of E-cadherin and α-catenin significantly.The result of dual luciferase assay showed that NRP1 was a downstream target gene of miR-9(P<0.05).CONCLUSION:miR-9 may inhibit the expression of EMT-related proteins through the downstream target gene NRP1,thus inhibiting the EMT of gastric cancer SGC-7901 cells.