阿帕替尼联合曲妥珠单抗对胃癌细胞的协同增敏作用

目的观察阿帕替尼联合曲妥珠单抗杀伤胃癌NCI-N87细胞的协同增敏作用并探讨可能作用机制。方法CCK-8法检测空白对照组、曲妥珠单抗组(0.1、1、10μg/ml)、阿帕替尼组(1μmol/L)及曲妥珠单抗(0.1、1、10μg/ml)+阿帕替尼(1μmol/L)组对NCI-N87细胞的增殖抑制作用,流式细胞术检测NCI-N87细胞凋亡,Western blotting检测HER-2、VEGFR2、Bax、Bcl-2蛋白表达。结果CCK-8检测提示曲妥珠单抗、阿帕替尼能够抑制NCI-N87细胞增殖,在一定浓度范围内作用呈浓度依赖性和时间依赖性(P<0.01);q值计算提示曲妥珠单抗与阿帕替尼具有协同抑制NCI-N87细胞增殖的作用。流式细胞术检测显示联合组NCI-N87胃癌细胞凋亡较单药组明显升高(P<0.05),其中空白对照组、阿帕替尼组(1μmol/L)、曲妥珠单抗(0.1μg/ml)组及曲妥珠单抗(0.1μg/ml)+阿帕替尼(1μmol/L)组的凋亡率分别为(3.0±1.28)%、(5.8±1.63)%、(8.0±3.92)%和(21.6±6.85)%。曲妥珠单抗+阿帕替尼组与空白对照组、曲妥珠单抗及阿帕替尼单药组比较,HER-2蛋白表达显著下调(P<0.05);曲妥珠单抗+阿帕替尼组与空白对照组比较,Bcl-2蛋白表达、Bcl-2/Bax比值明显降低(P<0.01)。结论阿帕替尼联合曲妥珠单抗可能通过下调HER-2蛋白及调控凋亡相关蛋白Bcl-2、Bax的表达,协同抑制NCI-N87细胞增殖和促进细胞凋亡。     

Gab2基因在胃癌中的表达及对胃癌细胞增殖、凋亡、迁移及AKT、p-AKT、Bax、Bcl-2表达的影响研究

目的 探讨Gab2基因在胃癌中的表达及对胃癌细胞增殖、凋亡、迁移及对AKT、p-AKT、Bax、Bcl-2表达的影响.方法 采用RT-PCR及Western Blot检测胃癌组织和癌旁组织中Gab2的表达.培养人胃癌细胞株SGC-7901,分别用Gab2小干扰RNA(Gab2-siRNA)和阴性对照(siRNA-NC)转染细胞,以空脂质体转染的细胞作为对照组,各组细胞培养48 h.应用Western Blot检测细胞中Gab2、AKT、p-AKT、Bax、Bcl-2蛋白表达的变化,CCK-8检测细胞增殖情况,流式细胞仪检测细胞凋亡,Transwell小室检测细胞迁移能力.结果 胃癌组织中Gab2的mRNA及蛋白表达水平均明显高于癌旁组织(P﹤0.01);Gab2-siRNA组Gab2蛋白表达水平明显低于对照组(P﹤0.01);siRNA-NC组细胞的存活率、凋亡率、迁移数及AKT、p-AKT、Bax、Bcl-2蛋白表达与对照组比较,差异均无统计学意义(P﹥0.05);Gab2-siRNA组细胞的AKT蛋白表达与对照组比较,差异无统计学意义(P﹥0.05),细胞的存活率、迁移数及p-AKT、Bcl-2蛋白表达明显低于对照组(P﹤0.01),细胞凋亡率及Bax蛋白表达明显高于对照组(P﹤0.01).结论 Gab2在胃癌组织高表达,沉默Gab2的表达能显著抑制人胃癌细胞株SGC-7901的增殖和迁移,并通过调节Bax、Bcl-2蛋白表达促进细胞凋亡,其可能的机制与AKT信号通路的调控有关.     

敲低PRMT5基因表达对胃癌细胞增殖、侵袭和凋亡的影响及其机制

目的 观察蛋白质精氨酸甲基转移酶5(PRMT5)在胃癌细胞中的表达,探讨敲低PRMT5表达水平后对胃癌细胞生物学行为的影响.方法 Western blot检测胃癌细胞系MGC803、SGC7901、MKN45和人胃黏膜上皮细胞GES-1中PRMT5蛋白表达水平,转染siRNA1和siRNA2质粒敲低PRMT5的表达水平...     

β-catenin SUMOylation is involved in the dysregulated proliferation of myeloma cells

Over-activation of SUMOylation is correlated with poor prognosis in multiple myeloma (MM), with the mechanism unclear. Wnt signaling is one of the aberrantly regulated pathways related to cancer tumorigenesis and progression. Whether SUMOylation is involved in regulating the activity of Wnt/β-catenin pathway, however, has not been reported in MM. Here we found that the TOPflash reporter activity and the expression of Wnt/β-catenin target genes can be down-regulated after interference with SUMOylation through SUMO-1 small interfering RNA (siRNA). SUMOylation inhibition down-regulated β-catenin at protein level via promotion of ubiquitin-proteasomal mediated degradation. Furthermore, over-expression of β-catenin rescued Wnt/β-catenin pathway activity and partially prevented increased apoptosis and growth inhibition induced by SUMOylation inhibition, indicating that β-catenin was responsible for the observed effect on Wnt/β-catenin pathway. To gain a clearer view, we exploited the inter-protein interactions of β-catenin and SUMO-1 in myeloma cell lines. Immunoprecipitation and immunofluorescence assay proved that β-catenin is subjected to SUMOylation in vivo, which may, at least partially explain the impact of SUMOylation inhibition on β-catenin. The association of SUMO-1 and β-catenin was confirmed in myeloma patient samples. Taken together, our data proved that SUMOylation inhibition down-regulates Wnt/β-catenin pathway by promoting the ubiquitin-proteasomal mediated degradation of β-catenin. SUMOylation of β-catenin is part of the mechanisms involved in the dysregulated proliferation of myeloma cells.     

莱菔硫烷对人黑色素瘤A375细胞自噬的影响

目的 探讨莱菔硫烷（sulforaphane,SFN）对人黑色素瘤A375细胞自噬的影响。方法 分别采用不同浓度（0 μmol·L^-1、5μmol·L^-1、10 μmol·L^-1、20 μmol·L^-1、40 μmol·L^-1）SFN及联合自噬抑制剂氯喹处理人黑色素瘤A375细胞后,采用MTT法检测细胞增殖情况,Real-time PCR和Western blot检测自噬相关分子LC3（LC3Ⅱ/LC3Ⅰ）、Beclin-1和p62以及凋亡相关分子Bcl-2、Bax和Caspase-3的表达水平。 结果 MTT法检测结果显示,SFN呈剂量依赖式抑制A375细胞增殖（F=21.517,P＜0.001）。与对照组比较,不同浓度（5 μmol·L^-1、10 μmol·L^-1、20 μmol·L^-1和40 μmol·L^-1） SFN均能上调自噬相关分子LC3Ⅱ、Beclin-1 mRNA和LC3Ⅱ/LC3Ⅰ、Beclin-1蛋白表达,上调促凋亡蛋白Bax、Caspase-3的表达（P<0.05）,同时下调自噬相关分子p62及抑凋亡蛋白Bcl-2的表达（P<0.05）。氯喹联合不同浓度SFN处理A375细胞后各组细胞增殖率均较相应剂量的单纯SFN处理组低（P<0.05）。结论 SFN可诱导黑色素瘤A375细胞自噬并促进细胞凋亡,联合自噬抑制剂氯喹能增强细胞增殖抑制作用,可能是黑色素瘤有效的治疗药物。     

Trastuzumab in combination with PEGylated interferon-α1b exerts synergistic antitumor activity through enhanced inhibition of HER2 downstream signaling and antibody-dependent cellular cytotoxicity

The anti-HER2 monoclonal antibody trastuzumab is the mainstay of treatment for HER2-positive breast and gastric cancer, and its combination with multiple chemotherapeutic agents has represented an effective and rational strategy in the clinic. In this study, we report that trastuzumab in combination with PEGylated interferon-α1b (IFN-α1b), a polyethylene glycol (PEG)-conjugated form of a subtype of interferon alpha (IFN-α), synergistically inhibited the proliferation of HER2-positive cells, including BT-474 and SK-BR-3 breast cancer cells and NCI-N87 gastric cancer cells, and also induced their apoptosis, but had no effect on HER2-negative MDA-MB-231 breast cancer cells. Trastuzumab inhibited phosphorylation of HER2, AKT and ERK, an effect that was enhanced by PEGylated IFN-α1b, likely owing to PEGylated IFN-α1b-mediated downregulation of HER2 through the lysosomal degradation pathway. Moreover, PEGylated IFN-α1b significantly enhanced trastuzumab-mediated antibody-dependent cellular cytotoxicity (ADCC) in HER2-positive cells. Importantly, trastuzumab combined with PEGylated IFN-α1b exhibited significant synergistic antitumor activity in HER2-positive BT-474 xenografts, an effect that was associated with enhanced inhibition of HER2 expression and AKT and ERK phosphorylation. Strikingly, depletion of natural killer cells with anti-Asialo GM1 antibody abrogated the synergistic antitumor activity, indicating that augmented ADCC is essential for this synergy. Taken together, our findings indicate that both enhanced inhibition of HER2 downstream signaling and augmented ADCC contribute to the synergistic antitumor activity of trastuzumab with PEGylated IFN-α1b, and imply that combining trastuzumab with PEGylated IFN-α1b could be a promising strategy for HER2-positive cancers.     

ING5 suppresses proliferation,apoptosis, migration and invasion,and induces autophagy and differentiation of gastric cancer cells: a good marker for carcinogenesis and subsequent progression

Here, we found that ING5 overexpression increased autophagy, differentiation, and decreased proliferation, apoptosis, migration, invasion and lamellipodia formation in gastric cancer cells, while ING5 knockdown had the opposite effects. In SGC-7901 transfectants, ING5 overexpression caused G₁ arrest, which was positively associated with 14-3-3 overexpression, Cdk4 and c-jun hypoexpression. The induction of Bax hypoexpression, Bcl-2, survivin, 14-3-3, PI3K, p-Akt and p70S6K overexpression by ING5 decreased apoptosis in SGC-7901 cells. The hypoexpression of MMP-9, MAP1B and flotillin 2 contributed to the inhibitory effects of ING5 on migration and invasion of SGC-7901 cells. ING5 overexpression might activate both β-catenin and NF-κB pathways in SGC-7901 cells, and promote the expression of down-stream genes (c-myc, VEGF, Cyclin D1, survivin, and interleukins). Compared with the control, ING5 transfectants displayed drug resistance to triciribine, paclitaxel, cisplatin, SAHA, MG132 and parthenolide, which was positively related to their apoptotic induction and the overexpression of chemoresistance-related genes (MDR1, GRP78, GRP94, IRE, CD147, FBXW7, TOP1, TOP2, MLH1, MRP1, BRCP1 and GST-π). ING5 expression was higher in gastric cancer than matched mucosa. It was inversely associated with tumor size, dedifferentiation, lymph node metastasis and clinicopathological staging of cancer. ING5 overexpression suppressed growth, blood supply and lung metastasis of SGC-7901 cells by inhibiting proliferation, enhancing autophagy and apoptosis in xenograft models. It was suggested that ING5 expression might be employed as a good marker for gastric carcinogenesis and subsequent progression by inhibiting proliferation, growth, migration, invasion and metastasis. ING5 might induce apoptotic and chemotherapeutic resistances of gastric cancer cells by activating β-catenin, NF-κB and Akt pathways.     

Protein kinase CK2α catalytic subunit is overexpressed and serves as an unfavorable prognostic marker in primary hepatocellular carcinoma

Protein kinase CK2 alpha (CK2α), one isoform of the catalytic subunit of serine/threonine kinase CK2, has been indicated to participate in tumorigenesis of various malignancies. We conducted this study to investigate the biological significances of CK2α expression in hepatocellular carcinoma (HCC) development. Real-time quantitative polymerase and western blotting analyses revealed that CK2α expression was significantly increased at mRNA and protein levels in HCC tissues. Immunohistochemical analyses indicated that amplified expression of CK2α was highly correlated with poor prognosis. And functional analyses (cell proliferation and colony formation assays, cell migration and invasion assays, cell cycle and apoptosis assays) found that CK2α promoted cell proliferation, colony formation, migration and invasion, as well as inhibited apoptosis in hepatoma cell lines in vitro. CK2α-silenced resulted in significant apoptosis in cells that was demonstrated been associated with downregulation of expression of Bcl-2, p-AKT (ser473) and upregulation of expression of total P53, p-P53, Bax, caspase3 and cleaved-caspase3 in HCC cells. In addition, experiments with a mouse model revealed that the stimulative effect of CK2α on tumorigenesis in nude mice. Our results suggest that CK2α might play an oncogenic role in HCC, and therefore it could serve as a biomarker for prognostic and therapeutic applications in HCC.     

小檗胺通过内质网应激通路诱导胃癌细胞A GS凋亡

目的:研究小檗胺对人胃癌细胞AGS增殖和凋亡的影响,并探讨其可能的作用机制.方法:应用3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)法测定细胞活力;膜联蛋白V/碘化丙啶(An-nexin V/PI)细胞凋亡法测定细胞凋亡;Western blot法测定Bcl-2、Bax、chop、GRP78和cle...     

Wnt/β-catenin,an oncogenic pathway targeted by H. pylori in gastric carcinogenesis

A section of gastric cancers presents nuclear β-catenin accumulation correlated with H. pylori infection. H. pylori stimulate Wnt/β-catenin pathway by activating oncogenic c-Met and epidermal growth factor receptor (EGFR), or by inhibiting tumor suppressor Runx3 and Trefoil factor 1 (TFF1). H. pylori also trigger Wnt/β-catenin pathway by recruiting macrophages. Moreover, Wnt/β-catenin pathway is found involved in H. pylori-induced gastric cancer stem cell generation. Recently, by using gastroids, researchers have further revealed that H. pylori induce gastric epithelial cell proliferation through β-catenin. These findings indicate that Wnt/β-catenin is an oncogenic pathway activated by H. pylori. Therefore, this pathway is a potential therapy target for H. pylori-related gastric cancer.     

Knockdown of HMGB1 improves apoptosis and suppresses proliferation and invasion of glioma cells

Background

The purposes of this study were to explore the effects of high mobility group protein box 1 (HMGB1) gene on the growth, proliferation, apoptosis, invasion, and metastasis of glioma cells, with an attempt to provide potential therapeutic targets for the treatment of glioma.

Methods

The expressions of HMGB1 in glioma cells (U251, U-87MG and LN-18) and one control cell line (SVG p12) were detected by real time PCR and Western blotting, respectively. Then, the effects of HMGB1 on the biological behaviors of glioma cells were detected: the expression of HMGB1 in human glioma cell lines U251 and U-87MG were suppressed using RNAi technique, then the influences of HMGB1 on the viability, cycle, apoptosis, and invasion abilities of U251 and U-87MG cells were analyzed using in a Transwell invasion chamber. Also, the effects of HMGB1 on the expressions of cyclin D1, Bax, Bcl-2, and MMP 9 were detected.

Results

As shown by real-time PCR and Western blotting, the expression of HMGB1 significantly increased in glioma cells (U251, U-87MG, and LN-18) in comparison with the control cell line (SVG p12); the vitality, proliferation and invasive capabilities of U251 and U-87MG cells in the HMGB1 siRNA-transfected group were significantly lower than those in the blank control group and negative control (NC) siRNA group (P<0.05) but showed no significant difference between the blank control group and NC siRNA group. The percentage of apoptotic U251 and U-87MG cells was significantly higher in the HMGB1 siRNA-transfected group than in the blank control group and NC siRNA group (P<0.05) but was similar between the latter two groups. The HMGB1 siRNA-transfected group had significantly lower expression levels of Cyclin D1, Bcl-2, and MMP-9 protein in U251 and U-87MG cells and significantly higher expression of Bax protein than in the blank control group and NC siRNA group (P<0.05); the expression profiles of cyclin D1, Bax, Bcl-2, and MMP 9 showed no significant change in both blank control group and NC siRNA group.

Conclusions

HMGB1 gene may promote the proliferation and migration of glioma cells and suppress its effects of apoptosis. Inhibition of the expression of HMGB1 gene can suppress the proliferation and migration of glioma cells and promote their apoptosis. Our observations provided a new target for intervention and treatment of glioma.     

Combination treatment of PD98059 and DAPT in gastric cancer through induction of apoptosis and downregulation of WNT/β-catenin

γ-secretase inhibitors (GSIs), the indirect inhibitors of Notch, are emerging as a new class of anticancer agents for the treatment of solid and hematological malignancies, but little is known about their effects on gastric cancer. In this study, we demonstrate that DAPT, a potent GSI, was effective to inhibit γ-secretase activity in gastric cancer (GC) cell lines that contained a fragment with approximately the size of the Notch1 intracellular domain (NICD), but was limited in their ability to induce apoptosis. However, activation of extracellular signal-regulated kinase (ERK)1/2 upon DAPT treatment was detected. Selective inhibition of ERK1/2 activation dramatically sensitized GC cells to apoptosis via downregulating β-catenin signaling in these GC cells. Notably, in a xenograft mouse tumor model, combination therapy using ERK inhibitor PD98059 plus DAPT yielded additive antitumor effects as compared with either agent alone. Taken together, these data demonstrated that γ-secretase inhibition combined with ERK1/2 inhibitor enhances cell death in GC cells partly through downregulation of WNT/β-catenin pathways.     

β-catenin inhibitors ICG-001 and pyrvinium sensitize bortezomib-resistant multiple myeloma cells to bortezomib

Although bortezomib (BTZ) displays efficacy in treating multiple myeloma (MM), BTZ resistance in MM patients has been reported. Meanwhile, treating BTZ resistant MM cells with β-catenin inhibitors have demonstrated the ability to reserve BTZ resistance. Thus, the present study aimed to investigate the synergistic effect of the β-catenin inhibitors, ICG-001 and pyrvinium (PP), with BTZ in the treatment of BTZ-resistant MM cells. Different concentrations of ICG-001 (0–32 µM) or PP (0–32 nM) were used to treat the BTZ-resistant RPMI-8226 (RPMI-8226BR) and BTZ-resistant KMS-11 (KMS-11BR) cell lines, followed by a BTZ combination treatment. Subsequently, cell viability and apoptosis in these two cell lines were determined by CCK-8 assay and flow cytometry, respectively. The proteins involved in the Wnt/β-catenin signaling pathway were detected using western blotting. The Wnt/β-catenin signaling pathway was activated in the RPMI-8226BR and the KMS-11BR cells. In addition, the cell viability of RPMI-8226BR and KMS-11BR cells were decreased following β-catenin inhibitor (ICG-001 and PP) treatment alone. Furthermore, the β-catenin inhibitors, ICG-001 and PP, plus BTZ combination treatment revealed a notable decrease in cell viability and a marked increase in cell apoptosis rate, compared with that in cells treated with ICG-001, PP or BTZ alone in the RPMI-8226BR and KMS-11BR cell lines. In conclusion, the β-catenin inhibitors, ICG-001 and PP not only increased apoptosis, but also sensitized BTZ-resistant MM cells to BTZ, indicating their potential therapeutic application in MM.