褪黑素的抗胃癌效应及其引起的Bcl-2、Bax、p21和p53的表达变化

为了探讨褪黑素体内抗小鼠胃癌作用及其机制,本研究应用小鼠胃癌(murine foregastric carcinoma,MFC)细胞建立荷胃癌小鼠模型,不同浓度褪黑素干预后,运用实时荧光定量RT-PCR、免疫印迹等方法检测Bcl-2,Bax,p21,p53的表达变化。结果显示:(1)褪黑素能够缩小荷胃癌小鼠的肿瘤体积,减轻肿瘤重量,达到抗胃癌作用;(2)褪黑素在抑制胃癌生长过程中下调肿瘤组织Bcl-2表达,上调Bax、p21和p53表达。以上结果表明,褪黑素可通过促进胃癌细胞凋亡从而实现体内抑制胃癌生长作用。     

山奈酚对胃癌细胞PARP1以及P53基因表达的影响研究

胃癌(GC)是最常见的恶性肿瘤之一,是人类健康的主要威胁,其发病机制是一个单基因或多基因逐步突变的过程,与细胞的侵袭、增殖和转移有关,包括癌基因遗传和表观遗传的突变、肿瘤抑制基因、DNA修复途径基因、细胞周期途径基因和幽门螺杆菌感染等。而山奈酚具有多种生物学活性,能够抑制多种肿瘤细胞的细胞周期,诱导肿瘤细胞凋亡从而抑制肿瘤细胞/组织的侵袭及转移。因此本研究用不同浓度的山奈酚处理胃癌细胞,并检测了胃癌细胞的形态变化情况、癌细胞凋亡相关因子P53和PARP1基因的表达水平和其对应的蛋白质表达变化。结果表明大于100μmol/L山奈酚处理后的胃癌细胞中P53基因和P53蛋白的表达水平被显著提高,而相反的PARP1基因和蛋白的表达则被显著抑制,且山奈酚处理后胃癌细胞的凋亡数目也明显增加,因此本实验结果表明,山奈酚能够有效的促进胃癌细胞凋亡的发生,以此来达到抑制癌细胞恶性增殖的作用。这一结果可以为后续针对胃癌新疗法的研究提供一些思路和理论支持。     

乙型肝炎病毒上调的lnc-HUR1抑制肝癌细胞凋亡北大核心CSCD

Lnc-HUR1是乙型肝炎病毒(hepatitis B virus,HBV)上调的长链非编码RNA,具有促进肝癌细胞增殖和促进肝癌发生发展的功能。为探究lnc-HUR1对肝癌细胞凋亡的影响,通过免疫印迹、实时荧光定量PCR、双荧光素酶报告基因、免疫共沉淀、流式细胞术等实验方法,检测lnc-HUR1对肝癌细胞凋亡的影响。转化生长因子-β(tansforming growth factor-β,TGF-β)、五氟尿嘧啶和星孢菌素诱导肝癌细胞凋亡的实验结果显示,过表达lnc-HUR1能够显著降低caspase3/7的活性以及PARP-1的剪切,而敲低lnc-HUR1则能够显著增加caspase3/7的活性,促进PARP-1的剪切;Annexin-Ⅴ和PI联合染色实验也表明过表达lnc-HUR1能够抑制细胞凋亡,敲低lnc-HUR1能够促进细胞的凋亡。同时过表达lnc-HUR1能够在RNA水平和蛋白水平上调凋亡抑制因子Bcl-2(B cell lymphoma-2)、下调促凋亡因子BAX(B cell lymphoma-2-associated x),从而抑制细胞的凋亡。在CCL4诱导的小鼠急性肝损伤模型中,lnc-HUR1转基因小鼠肝组织中Bcl-2的表达高于对照小鼠。染色质免疫共沉淀(chromatin immunoprecipitation,ChIP)实验也证实lnc-HUR1能够降低p53在Bcl-2和BAX启动子区的富集。以上结果说明,lnc-HUR1通过促进凋亡抑制因子Bcl-2及抑制凋亡促进因子BAX的表达抑制肝癌细胞的凋亡。进一步的实验表明,在HCT116细胞中lnc-HUR1能够调控Bcl-2和BAX的转录,而在HCT116 p53−/−细胞中,lnc-HUR1对Bcl-2和BAX的表达没有影响,说明lnc-HUR1对肝癌细胞凋亡的抑制作用依赖于p53的活性。综上所述,HBV上调的lnc-HUR1具有抑制肝癌细胞凋亡的作用,lnc-HUR1通过抑制p53转录活性,上调凋亡抑制因子Bcl-2、抑制凋亡促进因子BAX的转录,从而抑制细胞凋亡。上述结果提示Lnc-HUR1在HBV相关肝癌发生发展中发挥重要作用。     

光甘草定诱导小鼠黑色素瘤B16F10细胞凋亡的机制研究

通过体外和体内模型研究光甘草定对小鼠黑色素瘤B16F10细胞增殖的抑制作用及其分子机制。B16F10细胞经光甘草定处理后可抑制其增殖,且具有浓度依赖性;诱导B16F10细胞凋亡,观察到明显的细胞凋亡状态,细胞内凋亡相关基因及蛋白Bax表达显著上升,Bcl-2则表达下调。进一步的研究发现,经光甘草定处理后的B16F10细胞中,培养基中葡萄糖含量升高,而ATP含量、乳酸生成均降低;细胞内糖酵解相关基因及蛋白HK2、Ldha表达下调。同时,经光甘草定处理后,移植瘤小鼠的肿瘤组织生长受到明显抑制,肿瘤组织内细胞凋亡率显著升高,Bax表达明显上升,而Bcl-2、HK2和Ldha则表达均下调。说明,光甘草定在一定浓度范围内抑制了小鼠黑色素瘤B16F10细胞的增殖,诱导细胞凋亡,而其诱导细胞凋亡的机制可能与调控糖酵解相关基因的表达相关。     

白术抑制胃癌细胞SGC-7901增殖并促进其凋亡

目的观察白术对胃癌SGC-7901侧群细胞及非侧群细胞增殖及凋亡的影响。方法流式细胞仪分选SGC-7901中的侧群细胞;制备含白术药物血清;CCK-8法检测白术药物血清对细胞增殖能力的影响;流式细胞仪检测含白术药物血清对细胞凋亡的影响;Western blot检测药物血清对细胞中Bax及Bcl-2蛋白表达的影响;异种移植BALB/C小鼠成瘤实验观察白术对细胞体内成瘤能力影响;免疫组织化学检测白术对小鼠肿瘤组织中Bax及Bcl-2蛋白表达的影响。结果离体实验表明,含白术药物血清培养可明显降低SGC-7901侧群细胞的增殖率,同时可诱导其凋亡、分别上调和下调细胞中Bax和Bcl-2水平;在体实验显示,白术汤剂灌胃可显著抑制SGC-7901侧群细胞小鼠成瘤能力,分别上调和下调肿瘤组织中Bax和Bcl-2水平。非侧群细胞也有上述表现。结论白术可通过上调促凋亡蛋白Bax及下调抑凋亡蛋白Bcl-2从而促进胃癌SGC-7901侧群细胞及非侧群细胞凋亡,并抑制其增殖及体内成瘤能力。     

羽扇豆醇介导MDM2-p53通路对胃癌细胞生物学行为的影响

目的:探讨羽扇豆醇介导鼠双微基因2(Mouse double microgene 2,MDM2)-p53通路对胃癌细胞生物学行为的影响及相关机制。方法:对数生长期的胃癌小鼠MFC细胞株随机分为三组。实验1组与实验2组给予10 mg/L和20 mg/L的羽扇豆醇处理,对照组以等体积的1×磷酸盐缓冲液处理。对比三组MFC细胞细胞增殖、凋亡、迁移与侵袭,及MDM2-p53通路蛋白表达。结果:细胞处理后6 h与12 h,实验1组与实验2组的细胞增殖指数、细胞迁移与侵袭指数、MDM2蛋白相对表达水平显著低对于对照组,实验2组也低于实验1组,对比差异都有统计学意义(P<0.05)。细胞处理后6 h与12 h,实验1组与实验2组的细胞凋亡指数、p53蛋白相对表达水平显著高于对照组,实验2组也高于实验1组,对比差异都有统计学意义(P<0.05)。结论:羽扇豆醇能促进胃癌细胞p53蛋白的表达,抑制MDM2蛋白的表达,从而促进细胞凋亡,抑制胃癌的增殖、侵袭与转移,且具有剂量依赖性。     

白藜芦醇诱导肺癌A549细胞凋亡

本实验以人肺腺癌A549细胞为实验对象,白藜芦醇(Res)诱导细胞凋亡的效应及其机制进行了研究。用不同浓度Res处理A549细胞48 h后,癌细胞的形态和生物学反应发生了明显的变化。为了确证这些变化是特征性的细胞凋亡现象,采用MTT法检验了细胞存活率;光学和荧光显微镜观察了细胞形态结构;流式细胞术分别检测了细胞凋亡率、细胞周期和线粒体膜电位(△ψm);Real Time RT-PCR和Western blot测定了Bcl-2/Bax表达水平。结果显示,白藜芦醇能够抑制A549细胞生长,并呈剂量依赖性关系,经Res处理后的A549细胞48 h的最佳药物浓度是30μmol/L,增殖抑制率为(60.85±0.84)%,显微镜下观察细胞呈明显凋亡现象,细胞凋亡率为(17.44±0.28)%,△ψm显著下降(p0.01),使细胞阻滞于G2期和S期;下调Bcl-2,使Bax的表达明显增加,从而导致Bcl-2/Bax比值显著降低(p0.01)。这些结果表明白藜芦醇可能通过调节Bcl-2/Bax基因的途径,诱导人肺腺癌A549细胞凋亡,并抑制癌细胞的进一步增殖。     

瘦素对卵巢癌细胞 SKOV3 增殖及凋亡的影响

目的:探讨瘦素对人卵巢癌SKOV3细胞增殖及凋亡的影响及其作用机制。方法:用不同浓度的瘦素(0、50、100、200 ng/m L)处理人卵巢癌SKOV3细胞48 h后,采用MTT法检细胞的生长;以血清饥饿诱导细胞凋亡,同时给予瘦素刺激,Annexin V/PI双染法检测细胞凋亡的变化;western blotting分析p21、cyclin D1、Bcl-2、Bax蛋白的表达水平和ERK1/2通路的活化情况。结果:瘦素以剂量依赖性的方式促进人卵巢癌SKOV3细胞的增殖,同时抑制血清饥饿诱导的细胞凋亡。瘦素处理可下调p21和上调cyclin D1的表达,抑制促凋亡分子Bax的表达和上调抗凋亡分子Bcl-2的表达。瘦素可诱导细胞中ERK1/2通路的活化,其抑制剂PD98059可明显抑制瘦素诱导的促细胞增殖和抗凋亡作用,同时伴随有cyclin D1、Bcl-2蛋白表达的下调和Bax的上调。结论:瘦素可能通过活化ERK1/2通路调节细胞有丝分裂进程,进而促进卵巢癌细胞的增殖;同时通过调节凋亡相关蛋白Bcl-2和Bax的表达抑制卵巢癌细胞的凋亡。     

生物钟基因PER2在人口腔鳞癌细胞中具有重要的抑癌作用

探讨生物钟基因PER2对人口腔鳞癌SCC9细胞增殖、凋亡、迁移和侵袭的影响和机理。利用RNA干扰技术沉默SCC9细胞中PER2基因,应用实时荧光定量PCR检测Ki-67、MDM2、P53、Bcl-2、Bax、C-myc、MMP-2、Timp-2和VEGFm RNA的表达改变;流式细胞仪检测沉默后细胞的增殖和凋亡水平,平板克隆形成实验检测细胞的克隆形成率,Transwell小室检测细胞迁移和侵袭能力的改变。沉默PER2基因后,SCC9细胞凋亡指数显著降低(p0.05),细胞增殖指数、细胞迁移和侵袭能力显著升高(均p0.05)。PER2沉默后Ki-67、MDM2、Bcl-2、C-myc、MMP-2和VEGF m RNA的表达水平显著升高(均p0.05),p53、Bax和Timp-2 m RNA的表达水平显著降低(均p0.05)。研究表明,生物钟基因PER2通过调控Ki-67、MDM2、P53、Bcl-2、Bax、C-myc、MMP-2、Timp-2和VEGF影响癌细胞的增殖、凋亡、迁移和侵袭。因此,对PER2的深入研究有可能为癌症的治疗提供新的有效分子靶点。     

miR-1271-5p靶向PDK1促进胃癌细胞凋亡

目的 探讨miR-1271-5p在胃癌的作用和可能的作用机制。方法 RT-qPCR和原位杂交法检测胃癌组织和胃癌细胞株中miR-1271-5p的表达。Lipofectamine 2000转染miR-1271-5p mimics后,噻唑蓝（MTT）法和台盼蓝染色法检测SGC-790细胞的活性,Annexin V/PI染色检测细胞凋亡,JC-1探针检测线粒体膜电位,Western blot检测PDK1/Akt/凋亡信号相关蛋白的表达。荧光素酶法以及功能修复实验评估miR-1271-5p与PDK1的靶向关系。结果 胃癌组织和细胞中miR-1271-5p的表达降低。转染miR-1271-5p mimics后,SGC-790细胞的存活率下降,凋亡率上升,线粒体膜电位以及Bcl-2和p-AKT表达降低,Bax和Cleaved caspase-3表达增高。PDK1为miR-1271-5p的靶基因,过表达PDK1能逆转miR-1271-5p对胃癌细胞的促凋亡作用。结论 过表达miR-1271-5p可促进胃癌细胞凋亡,其机制可能与其靶向PDK1进而抑制AKT信号活性有关。     

Effect of epiberberine from Coptis chinensis Franch on inhibition of tumor growth in MKN-45 xenograft mice

Background and purposeGastric cancer is one of the major malignancies worldwide. Epiberberine (EPI) is a major alkaloid from Coptis chinensis Franch and the antitumor property of EPI remains poorly understood.MethodThe inhibition on gastric cancer cells was observed by MTT assays and colony formation experiments. The apoptosis, cell cycle, and reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) in gastric cancer cells were analyzed by Flow cytometry. The anti-tumor effect of EPI was evaluated with the MKN-45-beraring nude mice, and the potential mechanisms were explored by RNA-seq, qPCR, siRNA silencing and western blotting.ResultsEPI inhibited the proliferation of human gastric cancer cell lines MKN-45 (harboring wild-type p53) and HGC-27 (harboring mutant p53) in a dose dependent manner. EPI induced the apoptosis and cell cycle arrest in these two cell lines, of which MKN-45 cells are more sensitive to EPI than HGC-27 cells. Further experiments indicated that EPI induced the accumulation of ROS and decreased of ΔΨm in MKN-45 cells. The significant differentially expressed genes obtained by RNA-seq were distinctly enriched in the p53 signaling pathway. The apoptosis induced by EPI in MKN-45 cells would be effectively inhibited with the treatment of p53 siRNA and p53 inhibitor PFT-α. Western blotting demonstrated that EPI diminished the expression of Bcl-2 and XIAP, and increased those of p53, Bax, p21, p27, Cytochrome C and Cleaved-caspase 3. Animal experiments confirmed that EPI significantly alleviated tumor growth in MKN-45 xenograft mice via p53/Bax pathway.ConclusionsThese data indicated that EPI could be a novel anti-tumor candidate against MKN-45-related gastric cancer via targeting p53-dependent mitochondria-associated pathway.     

Synergistic Role between p53 and JWA: Prognostic and Predictive Biomarkers in Gastric Cancer

Expression of p53 appears to be correlated to prognosis in patients with malignancy, but its role in gastric carcinoma has remained controversial. Recently we reported that JWA, an ADP-ribosylation-like factor 6 interacting protein 5 (ARL6ip5), was both prognostic for overall survival and predictive for platinum-based treatment of gastric cancer. In this study, we aimed to investigate p53 expression as a prognostic and predictive marker in resectable gastric cancer, alone and in combination with JWA. Expression of p53 was examined in three large patient cohorts (total n = 1155) of gastric cancer. High expression of p53 was significantly correlated with unfavorable clinicopathologic parameters and decreased overall patient survival. Furthermore, patients with high p53 expression in tumors acquired remarkable survival benefit from adjuvant first-line platinum-based-chemotherapy. The synergy between p53 and JWA in predicting patient outcome was demonstrated, while no significantly elevated predictive value concerning chemotherapy was observed. Thus, p53 expression is a potent prognostic and predictive factor for resectable gastric cancer with adjuvant platinum-based chemotherapy. A combined effect of p53 with JWA as efficient prognostic indicators was found for the first time.     

PUMA作为细胞保护和肿瘤治疗靶点的研究进展

PUMA(p53 up-regulated modulator of apoptosis)是Bcl-2蛋白家族的促凋亡成员之一,具有强大的促凋亡作用。研究发现PUMA表达水平的降低与肿瘤的发生密切相关,上调PUMA在肿瘤细胞中的表达可以增强肿瘤细胞对放化疗的敏感性。PUMA的缺失可以有效降低由放、化疗引起的正常组织损伤。该文简要综述了PUMA在肿瘤治疗以及在放化疗引起的正常组织损伤中的作用进展。     

Acriflavine enhances radiosensitivity of colon cancer cells through endoplasmic reticulum stress-mediated apoptosis

Radiotherapy (RT) is one of the most effective tools in the clinical treatment of cancer. Because the tumor suppressor p53 plays a central role in radiation-mediated responses, including cell cycle-arrest and apoptosis, a number of studies have suggested that p53 could be a useful therapeutic target of anti-cancer agents. Accordingly, we sought to discover a new agent capable of increasing p53 activity. HCT116 colon cancer cells, containing wild-type p53, were stably transfected with a p53 responsive-luciferase (p53-Luc) reporter gene. A cell-based high-throughput screen of 7920 synthetic small molecules was performed in duplicate. Of the screened compounds, acriflavine (ACF) significantly increased p53-Luc activity in a concentration-dependent manner without causing toxicity. Pretreatment with ACF enhanced the induction of p53 protein expression and phosphorylation on serine 15 by γ-irradiation. Clonogenic assays showed that ACF pretreatment also potentiated radiation-induced cell death. The combination of irradiation and ACF treatment induced mitochondrial release of cytochrome c and significant activation of caspase-3 with PARP cleavage in colon cancer cells, demonstrating typical apoptotic cell death. Combined treatment with ACF and radiation increased the expression of Bax and Bad, while decreasing expression of Bcl-2. In addition, the ACF/radiation treatment combination induced endoplasmic reticulum (ER) stress responses mediated by IRE1α (inositol-requiring transmembrane kinase and endonuclease 1α), eIF-2α (eukaryotic initiation factor 2α), caspase-2/12, and CHOP (C/EBP homologous protein). The knockdown of IRE1α by siRNA inhibited the apoptotic cell death induced by ACF/radiation treatment. In vivo studies showed that combined treatment with ACF and radiation significantly inhibited the growth of tumors in colorectal cancer xenografted mice. These results indicate that ACF acts through p53-dependent mitochondrial pathways and ER stress signals, and could be a promising radiosensitizer.     

Matrine involves in the progression of gastric cancer through inhibiting miR-93-5p and upregulating the expression of target gene AHNAK

Matrine, also known as oxymatrine, is an important active ingredient of traditional Chinese herb Sophora flavescens. Recent studies have found that matrine may inhibit multiple tumors through inhibiting the tumor cell proliferation, inducing cell apoptosis, blocking cell cycle, suppressing cell invasion and migration and assisting in the synergy, and attenuation of radiotherapy and chemotherapy. This study mainly investigated the role of matrine in gastric cancer and its possible mechanism. The real-time fluorescence quantitative polymerase chain reaction technique showed that matrine inhibited the proliferation and migration of gastric tumor cells and significantly suppressed the expression of miR-93-5p. The dual-luciferase reporter gene assay indicated that AHNAK was a target gene of miR-93-5p and regulated by miR-93-5p and matrine. The torsion test demonstrated that matrine exerted its role via miR-93-5p while miR-93-5p played a role by targeting AHNAK. Thus, this study found that matrine affected the progression of gastric cancer by inhibiting the function of gastric cancer cells through the possible mechanism of inhibiting miR-93-5p expression to increase the expression level of the downstream target gene AHNAK.     

Sensitization by glycerol for CDDP-therapy against human cultured cancer cells and tumors bearing mutated p53 gene

To clarify effective chemotherapeutic regimens against cancer, we examined the effects of glycerol on apoptosis induced by CDDP treatment using cultured human cancer cells (in vitro) and transplanted tumor in mice (in vivo). Human tongue cell carcinoma (SAS) cells transfected with mutated p53 gene (SAS/m p53) showed CDDP-resistance compared with the cells with neo control gene (SAS/ neo). When those cultured cells were pre-treated with glycerol, CDDP-induced apoptosis was enhanced by glycerol in SAS/m p53 cells but not in SAS/ neo cells.In tumor-transplanted mice, the glycerol treatment to tumors enhanced growth delay induced by CDDP in mp53 tumors transplanted with SAS/m p53 cells, but not in wtp53 tumors transplanted with SAS/ neo cells. When transplanted tumors were treated with CDDP alone, the cells positive for active caspase-3, 85 kDa PARP and apoptosis were observed by immunohistochemical staining in wtp53 tumors but not in mp53 tumors. When the tumors were treated with CDDP combined with glycerol, positive cells were observed not only in wtp53 tumors but also in mp53 tumors. These results showed that the CDDP-induced growth inhibition of the tumors is p53 -dependent and that the enhanced growth delay by glycerol may be due to the increased apoptosis. Glycerol might be available for cancer chemotherapy in patients with mp53 tumors.     

Upregulation of periostin prevents P53-mediated apoptosis in SGC-7901 gastric cancer cells

Periostin is frequently upregulated in human cancers including gastric cancer and implicated in cancer cell proliferation, invasion, and epithelial–mesenchymal transition. This study was undertaken to investigate the effects of periostin overexpression on the chemosensitivity of gastric cancer cells. We constructed a stable cell line overexpressing periostin in SGC-7901 human gastric cancer cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay revealed that periostin had no influence on the proliferation of SGC-7901 cells. Compared to empty vector-transfected cells, overexpression of periostin rendered SGC-7901 cells more resistant to cisplatin or 5-fluorouracil (5-FU)-induced apoptosis, accompanying with less release of cytochrome c from mitochondria and diminished cleavage of caspase-3 and poly (ADP-ribose) polymerase. Periostin-overexpressing cells treated with cisplatin or 5-FU showed significantly (p < 0.05) decreased expression of Bax and p53 proteins and increased expression of Bcl-2 protein, when compared to drug-treated mock counterparts. Restoration of p53 expression by delivering wild-type p53 gene resulted in a marked increase in drug-induced apoptosis in periostin-overexpressing SGC-7901 cells. Periostin overexpression elevated the phosphorylation of Akt. Pretreatment of periostin-overexpressing cells with an Akt inhibitor, MK-2206, partially rescued periostin-mediated inhibition of p53 expression and drug resistance. Taken together, our data indicate that periostin confers protection against cisplatin or 5-FU-induced apoptosis in SGC-7901 cells, likely through modulating the Akt/p53 pathway, and thus represents a potential therapeutic target in gastric cancer.