Transforming growth factor-beta1 signaling blockade attenuates gastric cancer cell-induced peritoneal mesothelial cell fibrosis and alleviates peritoneal dissemination both in vitro and in vivo

Peritoneal dissemination is the most frequent metastatic pattern of advanced gastric cancer and the main cause of death in gastric cancer patients. Transforming growth factor-beta1 (TGF- ß1), one of the most potent fibrotic stimuli for human peritoneal mesothelial cells, has been shown to play an important role in this process. In this study, we investigated the effect of TGF- ß1 signaling blockade in gastric cancer cell (GCC)-induced human peritoneal mesothelial cell (HPMC) fibrosis. HPMCs were cocultured with the high TGF- ß1 expressing GCC line SGC-7901 and various TGF- ß1 signaling inhibitors or SGC-7901 transfected with TGF-ß1-specific siRNA. HPMC fibrosis was monitored on the basis of morphology. Expression of the epithelial cell marker, E-cadherin, and the mesenchymal marker, α-smooth muscle actin (α-SMA), was evaluated by Western blotting and immunofluorescence confocal imaging. GCC adhesion to HPMC was also assayed. In nude mouse tumor model, the peritoneal fibrotic status was monitored by immunofluorescent confocal imaging and Masson’s trichrome staining; formation of metastatic nodular and ascites fluid was also evaluated. Our study demonstrated that GCC expressing high levels of TGF-ß1 induced HMPC fibrosis, which is characterized by both upregulation of E-cadherin and downregulation of α-SMA. Furthermore, HPMC monolayers fibrosis was reversed by TGF- ß1 signaling blockade. In vivo, the TGF- ß1 receptor inhibitor SB-431542 partially attenuated early-stage gastric cancer peritoneal dissemination (GCPD). In conclusion, our study confirms the significance of TGFß1 signaling blockade in attenuating GCPD and may provide a therapeutic target for clinical therapy.     

miR-34a regulates cisplatin-induce gastric cancer cell death by modulating PI3K/AKT/survivin pathway

The purposes of this study were to determine the expression profiles of microRNA-34a (miR-34a) in human gastric cancer cell line (SGC-7901) and cisplatin-resistant cell lines (SGC-7901/DDP), and to establish the correlation between miR-34a expression profile and the sensitivity of human gastric cancer cell to cisplatin-based pattern, thereby providing new methods and strategies for treating gastric cancer. Gastric cancer cell line (SGC-7901) and cisplatin-resistant cell line (SGC-7901/DDP) were cultivated in vitro, respectively. Quantitative real-time PCR (qRT-PCR) and Western blot were utilized to determine the expression profiles of miR-34a and survivin in both gastric cancer cell lines. With miR-34a mimic and miR-34a inhibitor transfected into SGC-7901 and SGC-7901/DDP for 48 h, post-transfection changes of miR-34a expression was determined; the effects of miR-34a ectopic expression on the viability of cisplatin-induce gastric cancer cell were assayed by the MTT method. The effects of miR-34a ectopic expression on apoptosis of cisplatin-induce gastric cancer cell were determined by Annexin V/propidium iodide (PI) double staining method and flow cytometry. The effects of miR-34a ectopic expression on the AKT and p-AKT expression of cisplatin-induce gastric cancer cells were determined by Western blot and flow cytometry with the PI3K pathway inhibitor Wortmannin. As shown by qRT-PCR and Western blot analyses, the expression of miR-34a in cisplatin-resistant cell lines decreased significantly in comparison to that of SGC-7901 cell line (p?<?0.05), while significant up-regulation of survivin expression was also observed (p?<?0.05). Compared with the control group, the expression of miR-34a increased significantly in SGC-7901 cells transfected with miR-34a mimic for 48 h (p?<?0.01). After miR-34a inhibitor transfection, the expression of miR-34a decreased significantly (p?<?0.05). The viability of cisplatin-induce gastric cancer cells increased significantly (p?<?0.05) with significant decrease of apoptosis after miR-34a expression inhibition, as demonstrated by MTT and flow cytometry with miR-34a over-expression, the viability of cisplatin-induce gastric cancer cells decreased significantly (p?<?0.05), with significant apoptosis increase (p?<?0.05). As shown by Western blot and flow cytometry, in comparison to the control group, Wortmannin could inhibit miR-34a inhibitor and DDP induced up-regulation of p-AKT significantly (p?<?0.05) and stimulated apoptosis. In conclusion, miR-34a expression was down-regulated in cisplatin-resistant cell lines. miR-34a over-expression could improve the sensitivity of gastric cancer cells against cisplatin-based chemotherapies, with PI3K/AKT/survivin signaling pathway possibly involved in the mechanism.     

Expression and regulatory function of miRNA-34a in targeting survivin in gastric cancer cells

We aimed to investigate the expression of microRNA-34a (miR-34a) in human gastric cancer cells and to evaluate the effects of miR-34a, acting via its gene survivin, on gastric cancer cell HGC-27 to provide potential new strategies for treating gastric cancer. In vitro cultures of the human gastric cancer cell lines MGC80-3, HGC-27, NCI-N87, and SGC-7901 and the normal human gastric epithelial cell line GES-1 were established. The expression of miR-34a in each gastric cancer cell line and GES-1 normal human gastric epithelial cell line was detected using quantitative real-time polymerase chain reaction (qRT-PCR). After the HGC-27 cells were transfected with a miR-34a mimic for 48 h, the changes in the expression levels of miR-34a were detected using qRT-PCR. The effect of miR-34a on HGC-27 cell viability was measured using a tetrazolium-based colorimetric [?(4,5)-dimethylthiahiazo-(?z-y1)-3,5-di-phenytetrazoliumromide (MTT)] assay. Flow cytometry was used to analyze the effects of miR-34a on HGC-27 cell proliferation. Annexin V/propidium iodide double staining and flow cytometry were used to analyze the effects of miR-34a on HGC-27 cell apoptosis. A Transwell invasion chamber was used to detect the effects of miR-34a on HGC-27 cell invasion. Finally, western blotting was used to analyze the effects of miR-34a on survivin protein expression. The qRT-PCR test determined that miR-34a expression in gastric cancer cells was significantly reduced compared to the normal gastric epithelial cell line GES-1 (p?<?0.01). Compared to the control group, cellular miR-34a expression levels were significantly increased in HGC-27 human gastric carcinoma cells after transfection with a miR-34a mimic for 48 h (p?<?0.01). The MTT assay demonstrated that after overexpressing miR-34a in HGC-27 cells, cellular viability was significantly reduced (p?<?0.05). Flow cytometry analysis determined that upon miR-34a overexpression, the proliferation index decreased significantly (p?<?0.05), and cellular apoptosis was significantly increased (p?<?0.01). The Transwell invasion chamber assay illustrated that after increasing the expression of miR-34a, the number of cells passing through the Transwell chamber was significantly reduced (p?<?0.01). Based on western blotting, compared with the control group, survivin protein expression levels were significantly decreased in the HGC-27 cells transfected with the miR-34a mimic for 48 h (p?<?0.01). In conclusion, the expression level of miR-34a was downregulated in human gastric cancer cell lines. miR-34a can negatively regulate survivin protein expression and inhibit gastric cancer cell proliferation and invasion. Therapeutically enhancing miR-34a expression or silencing the survivin gene may benefit patients with gastric cancer.     

Decreased expression of CCNG2 is significantly linked to the malignant transformation of gastric carcinoma

This study aimed to analyze the expression, clinical significance of cyclin G2 (CCNG2) in gastric carcinoma, and the biological effect in its cell line by CCNG2 overexpression. Immunohistochemistry and western blot were used to analyze CCNG2 protein expression in 87 cases of gastric cancer and normal tissues to study on the relationship between CCNG2 expression and clinical factors. CCNG2 lentiviral vector was transfected into gastric SGC-7901 cell line. RT-PCR and western blot were used to detect the mRNA level and protein of CCNG2. MTT assay and cell cycle were also conducted as to the influence of the upregulated expression of CCNG2 that might be found on SGC-7901 cell biological effect. Immunohistochemically, the level of CCNG2 protein expression was found to be significantly lower in gastric cancer tissue than in normal tissues (P?<?0.05). Western blot shows that the relative amount of CCNG2 protein in gastric cancer tissue was found to be significantly lower than in normal tissues (P?<?0.05). The level of CCNG2 protein expression was correlated with T stages, lymph node metastasis, clinical stage, and histological grade (P?<?0.05). Loss of CCNG2 expression correlated significantly with poor overall survival time by Kaplan–Meier analysis (P?<?0.05). The result of biological function showed that SGC-7901 cell-transfected CCNG2 had a lower survival fraction, higher percentage of the G0/G1 phases, and lower CDK2 protein expression compared with SGC-7901 cell untransfected CCNG2 (P?<?0.05). CCNG2 expression decreased in gastric cancer and correlated significantly T stages, lymph node metastasis, clinical stage, histological grade, and poor overall survival, suggesting that CCNG2 may play important roles as a negative regulator to gastric cancer cell by promoting degradation of CDK2.     

RNAi-mediated gene silencing of vascular endothelial growth factor-C inhibits tumor lymphangiogenesis and growth of gastric cancer in vivo in mice

Overexpression of vascular endothelial growth factor-C (VEGF-C) has been implicated as a critical molecular signal in tumor development by promoting intratumoral lymphangiogenesis. The aim of this study was to explore whether small hairpin RNA (shRNA) targeting VEGF-C could inhibit gastric cancer lymphangiogenesis and tumor growth. Plasmid-mediated expression of VEGF-C–shRNA was employed to silence VEGF-C gene expression in human SGC-7901 cell lines. The inhibition of the target gene expression was quantified by real-time quantitative polymerase chain reaction, Western blotting, and enzyme-linked immunosorbent assay. In vitro, the cell viability was determined by MTT assay, flow cytometry analysis, and migration assay. After VEGF-C knockdown was confirmed, the stable cells were inoculated into nude mice. Tumor growth, lymph vessel density (LVD), and microvascular density were compared for mice administered either VEGF-C–shRNA or control. VEGF-C–shRNA causes effective and specific downregulation of VEGF-C expression (P?<?0.05). The migration activity of SGC-7901 cells was attenuated in vitro (P?<?0.05). Tumor growth rate and LVD was suppressed in vivo (P?<?0.05). VEGF-C–shRNA effectively suppressed gastric cancer cell migration in vivo, retards tumorigenicity, and lymphangiogenesis in nude mice.     

livin在人胃癌组织中的表达及其沉默后对胃癌细胞凋亡的影响

目的探讨凋亡抑制蛋白livin在人胃癌组织中的表达及其与临床病理的关系,研究小分子干扰RNA(siRNA)对胃癌细胞系(SGC-7901)livin基因表达的抑制作用,以及livin基因沉默后对胃癌细胞凋亡的影响。方法采用RT-PCR方法和Western blot法检测胃不同组织中livin基因mRNA和蛋白的表达,分析livin表达与临床病理的关系;设计两条针对人源livin基因的siRNA,分别转染SGC-7901细胞;RT-PCR法检测转染前后livin基因的表达情况,四甲基偶氮唑盐(MTT)法检测转染前后细胞增殖能力的变化以及细胞对5-氟尿嘧啶(5-Fu)、顺铂的半数抑制浓度(IC_(50))的改变,流式细胞术检测转染前后细胞凋亡变化。结果40例胃癌组织中,livin表达阳性率为47.5%(19/40);在癌旁组织和良性病变胃黏膜组织中,livin表达呈阴性。组织分化程度差、淋巴结转移者的livin表达率高(P<0.05)。livin特异性siRNA转染48h后,SGC-7901细胞中的livin mRNA表达受到抑制,细胞增殖能力减弱,对5-Fu和顺铂凋亡敏感性增加,同时IC_(50)降低(P<0.05)。结论livin在胃癌组织中表达增高,且与组织分化程度和淋巴结转移有关,可作为辅助胃癌预后判断的分子标志之一;RNA干扰可明显抑制livin基因表达,并使胃癌细胞的凋亡敏感性增加;livin有可能成为通过诱导细胞凋亡增强胃癌治疗效果的一个分子靶点。     

Induction of apoptosis in human peritoneal mesothelial cells by gastric cancer cell supernatant promotes peritoneal carcinomatosis

This study was carried out to evaluate the effects of gastric cancer cell supernatant on human peritoneal mesothelial cell viability and apoptosis and to investigate the mechanism of action of gastric cancer in a mesothelial cell line (HMrSV5). Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide (MTT) assay. Mesothelial cells treated with gastric cancer cell supernatant were stained with acridine orange/ethidium bromide and subjected to fluorescence microscopy. C57BL/6 mice were used to establish a cancer invasion model. Morphological changes and exfoliation occurred, and naked areas appeared in both cultured mesothelial cells and the parietal peritoneum after treatment with gastric cancer cell supernatant. Cell supernatant from gastric cancer cells induced apoptosis of mesothelial cells in a time-dependent manner. Obvious morphological changes of cell apoptosis were detected, such as condensation of chromatin, nuclear fragmentations, and apoptotic ladders. These findings demonstrate that gastric cancer cells induce apoptosis of human peritoneal mesothelial cells through supernatants in early peritoneal metastasis.     

乳斑肿瘤相关巨噬细胞诱导人腹膜间皮HMR-sv5细胞损伤的机制研究

  目的   研究胃癌细胞对巨噬细胞的诱导作用, 分析活化巨噬细胞对间皮细胞的损伤作用及机制。   目法   人正常胃腺上皮细胞系GES-1及人低分化胃癌细胞系SGC-7901与人单核巨噬细胞THP-1共培养, 诱导后者分化, 研究后者对人腹膜间皮细胞HMR-sv5的损伤作用及分子机制。   结果   胃癌细胞诱导THP-1形成肿瘤相关巨噬细胞(TAM), M1型巨噬细胞表面抗原的表达显著下调, 而M2表型的表面抗原明显上调, 细胞形态也发生明显改变。TAM显著抑制正常间皮细胞生长, 促进间皮细胞凋亡和上皮间质转化。   结论   胃癌细胞诱导巨噬细胞发生表型和功能转化, 进而导致间皮细胞发生EMT和凋亡, 促进形成腹膜转移癌。      

miR-361-5p通过靶向CCND1逆转胃癌SGC-7901细胞奥沙利铂耐药性

目的:探讨miR-361-5p对胃癌SGC-7901细胞奥沙利铂(oxaliplatin,OXA)耐药性的影响及其作用机制.方法:采用qPCR法检测miR-361-5p在胃癌细胞MKN-45、MGC80-3、SGC-7901和OXA耐药细胞SGC-7901/OXA中的表达水平.利用脂质体转染技术分别将miR-361-5...     

西黄浸提液抑制胃癌SGC-7901 细胞增殖的可能机制

[摘要] 目的：探讨西黄浸提液对胃癌SGC-7901 细胞增殖的影响及其可能机制。方法：常规培养胃癌细胞株SGC-7901,用CCK-8 法和细胞流式细胞术检测不同质量浓度（3.2、6.4、12.8 和25.6 mg/ml）的西黄浸提液在不同时间点（24、48 和72 h）对SGC-7901 细胞增殖和凋亡的影响,用qPCR法检测不同质量浓度西黄浸提液对SGC-7901 细胞凋亡相关基因Bax 和Bcl-2 mRNA表达的影响,用Western blotting 检测西黄浸提液对凋亡相关蛋白caspase 3、caspase 9、Bax和Bcl-2 表达的影响。结果：3.2~25.6 mg/ml的西黄浸提液均能有效地抑制胃癌SGC-7901 细胞的增殖（P<0.05 或P<0.01）,并且随浓度增加SGC-7901 细胞凋亡率增加（P<0.01）。西黄浸提液能够显著上调SGC-7901 细胞Bax mRNA和下调Bcl-2 mRNA表达水平（P<0.05 或P<0.01）,并可增加caspase3、caspase 9 和Bax 蛋白表达、降低Bcl-2 蛋白表达（P<0.05 或P<0.01）。结论：西黄浸提液通过触发细胞凋亡抑制胃癌SGC-7901细胞的增殖,此可成为一个潜在的胃癌辅助治疗的方法。     

姜黄素诱导人胃癌细胞SGC-7901凋亡的作用机制

 目的 探讨姜黄素诱导人胃癌细胞SGC-7901凋亡的作用及其相关机制。方法 以不同浓度的姜黄素作用于胃癌SGC-7901细胞，利用倒置相差显微镜观察细胞生长形态变化，通过MTT检测细胞生长抑制率，流式细胞术检测细胞凋亡，Western blot 检测胃癌细胞中Fas及survivin的表达情况。结果 姜黄素能显著抑制体外培养的SGC-7901细胞的生长并呈量-效和时-效关系，流式细胞术检测到亚二倍体凋亡峰，细胞凋亡率增加，Western blot结果提示经姜黄素作用后Fas表达率上升，survivin表达率下降。结论 姜黄素能抑制胃癌细胞SGC-7901的生长并促进其凋亡，姜黄素可能通过上调Fas及下调survivin的表达而诱导凋亡。     

沉默ERK5对胃癌SGC-7901、BGC-823细胞生物学功能的影响

目的 探讨沉默细胞外信号调节激酶5（extracellular signal regulated kinase 5,ERK5）对胃癌细胞SGC-7901、BGC-823生物学功能的影响。方法 实时荧光定量PCR法（qRT-PCR）检测人胃癌细胞株和人胃黏膜上皮细胞株ERK5 mRNA的表达水平。应用短发荚RNA（shRNA）干扰技术沉默胃癌细胞SGC-7901、BGC-823中ERK5的表达。CCK-8法检测ERK5沉默后胃癌细胞的生长能力,平板克隆实验检测细胞克隆形成能力,Transwell 实验检测细胞侵袭和迁移能力,流式细胞仪检测细胞凋亡和周期分布。结果 与胃黏膜上皮细胞GES-1相比,胃癌细胞SGC-7901、BGC-823、AGS、HGC-27中ERK5 mRNA均呈高表达,相对表达量分别为2.696±0.501、1.865±0.185、1.793±0.137和1.530±0.093（P<0.05）。ERK5-shRNA有效沉默胃癌细胞SGC-7901、BGC-823中ERK5的表达水平,沉默效率分别为（74.4±1.5）%和（69.1±3.9）%,差异有统计学意义（P<0.05）。沉默 ERK5的表达能有效抑制胃癌细胞增殖、克隆形成、迁移和侵袭能力（P<0.05）,而促进胃癌细胞凋亡（P<0.05）,并诱导细胞周期阻滞于G0/G1期。结论 沉默ERK5可显著抑制胃癌细胞SGC-7901、BGC-823的生长侵袭,促进细胞凋亡,ERK5可能是胃癌治疗的潜在靶点。     

Transduction of soluble Flt-1 gene to peritoneal mesothelial cells can effectively suppress peritoneal metastasis of gastric cancer

The prognosis of gastric cancer with peritoneal metastasis has not improved. Despite many promising studies, gene therapy has limited clinical application because of the lack of suitable vector systems to enable selective gene transduction to tumor cells. The aim of this study was to clarify whether gene therapy targeted to peritoneal mesothelial cells (PMCs) can inhibit peritoneal dissemination of gastric cancer. In vitro experiments showed that adenovirus expressing LacZ infected human omental tissue-derived PMCs more efficiently than human gastric cancer cell lines MKN1 and MKN45. When adenovirus expressing LacZ was injected into the peritoneal cavity of nude mice, the expression was detected in the peritoneum for at least 4 weeks. Furthermore, when adenovirus expressing soluble Flt-1 (Ad-sFLT-1) was i.p. administered in vivo, a high level of sFlt-1 protein could be detected in peritoneal lavage for 8 weeks. When MKN45 cells were i.p. inoculated 3 days after adenoviral vector injection, Ad-sFLT-1 markedly reduced the number of metastatic nodules larger than 1 mm in diameter on the peritoneal surface, and significantly prolonged the survival of nude mice without any significant side effects. Thus, peritoneal dissemination was significantly suppressed by a single i.p. injection of Ad-sFlt-1. Anti-angiogenic gene therapy targeted to PMCs could be a novel and practical strategy against peritoneal dissemination of gastric cancer, because it does not require tumor-specific gene transfer.     

pseudo-G-Rh2 induces mitochondrial-mediated apoptosis in SGC-7901 human gastric cancer cells

This study was designed to investigate the effect of pseudo-G-Rh2, a novel metabolite of ginsenoside Rh2, on the apoptosis of SGC-7901 human gastric cancer cells. Pseudo-G-Rh2 demonstrated antitumor activity and significantly inhibited the proliferation of SGC-7901 cells in a concentration-dependent manner. After treatment with pseudo-G-Rh2, SGC-7901 cells showed typical apoptotic morphological features, such as chromatin condensation and DNA fragmentation. Pseudo-G-Rh2 could induce mitochondrial membrane potential loss, which led to the release of cytochrome c (Cyt?c), Smac/Diablo and apoptosis-inducing factor (AIF) to the cell cytoplasm. Furthermore, pseudo-G-Rh2 exposure not only decreased the expression of the Bcl-2 protein but also increased the expression of the Bax protein and the activities of caspase-9 and caspase-3 in SGC-7901 cells. These results demonstrated that pseudo-G-Rh2 inhibited the proliferation of SGC-7901 cells by initiating apoptosis. Pseudo-G-Rh2-induced apoptosis was associated with a drop in the mitochondrial transmembrane potential, down-regulation of Bcl-2, up-regulation of Bax and activation of caspase-9 and caspase-3.     

HDAC5对胃癌SGC-7901细胞增殖和凋亡的影响

  目的   探讨HDAC5在胃癌细胞中的表达及其对胃癌SGC-7901细胞增殖和凋亡的影响。  方法   通过Western blot检测HDAC5和Twist1在胃癌细胞株及正常胃黏膜上皮细胞中的表达。使用MTT及流式细胞术分别检测HDAC5和Twist1对胃癌SGC-7901细胞增殖和凋亡的影响。  结果   HDAC5和Twist1在胃癌细胞株中的表达量均明显高于正常胃黏膜上皮细胞（P < 0.05）。沉默HDAC5的表达可使胃癌SGC-7901细胞中Twist1表达降低,并抑制其增殖、促进凋亡;而过表达HDAC5作用相反（P < 0.05）。此外,沉默Twist1可抑制SGC-7901细胞的增殖、促进其凋亡（P < 0.05）。  结论   HDAC5可能通过上调Twist1的表达水平促进胃癌细胞的增殖、抑制凋亡,从而促进胃癌的发生发展。      

IRX1 influences peritoneal spreading and metastasis via inhibiting BDKRB2-dependent neovascularization on gastric cancer

The overexpression of IRX1 gene correlates with the growth arrest in gastric cancer. Furthermore, overexpression of IRX1 gene suppresses peritoneal spreading and long distance metastasis. To explore the precise mechanisms, we investigated whether restoring IRX1 expression affects the angiogenesis or vasculogenic mimicry (VM). Human umbilical vein endothelial cells (HUVECs) and chick embryo and SGC-7901 gastric cancer cells were used for angiogenesis and VM analysis. Small interfering RNA was used for analyzing the function of BDKRB2, a downstream target gene of IRX1. As results, the remarkable suppression on peritoneal spreading and pulmonary metastasis of SGC-7901 cells by IRX1 transfectant correlates to reduced angiogenesis as well as VM formation. Using the supernatant from SGC-7901/IRX1 cells, we found a strong inhibiting effect on angiogenesis both in vitro and in chick embryo. SGC-7901/IRX1 cells revealed strong inhibiting effect on VM formation too. By gene-specific RNA interference for BDKRB2, or its effector PAK1, we got an effective inhibition on tube formation, cell proliferation, cell migration and invasion in vitro. In conclusion, enforcing IRX1 expression effectively suppresses peritoneal spreading and pulmonary metastasis via anti-angiogenesis and anti-VM mechanisms, in addition to previously found cell growth and invasion. BDKRB2 and its downstream effector might be potential targets for anti-cancer strategy.     

巴佛洛霉素A1抑制胃癌SGC-7901细胞中VEGF-C的表达

目的:研究巴佛洛霉素A1(Bafilomycin A1)对胃癌细胞株SGC-7901的增殖、迁移和血管生成的影响,并探讨可能的机制.方法:巴佛洛霉素A1(10 nmol/mL)处理SGC-7901细胞后,检测液泡-ATP酶(vacular-ATPases,V-ATPases)活性及培养液pH值,并分别用CCK-8法检测...