PRL-3基因对结直肠癌细胞增殖能力的影响

目的:探讨PRL-3的过表达或敲低对结直肠癌细胞增殖能力的影响.方法:利用MTT法、平板克隆形成实验检测PRL-3对细胞体外增殖的影响;应用流式细胞术检测PRL-3对细胞周期的影响.结果:应用MTT法,检测PRL-3对SW480/EGFP、SW480-EGFP-PRL-3、SW480/EGFP/Mock及SW480-PRL-3-KD1细胞体外增殖能力的影响,经析因方差分析,4组差异具有显著性(F=23.463,P=0.000);不同时间点对细胞体外增殖的影响差异具有显著性(F=71.515,P=0.000);各组细胞与各时间组两因素交互效应显著(F=2.128,P=0.008);除第1天外,其他各时间点细胞组间的细胞增殖差异具有显著性.经LSD法多重比较,结果表明,与SW480/EGFP/Mock和SW480/EGFP细胞相比,SW480-EGFP-PRL-3细胞的增殖速度加快,而SW480-PRL-3-KD1细胞的增殖速度减慢.平板克隆形成实验显示SW480-EGFP-PRL-3细胞克隆形成能力明显增强,而SW480-PRL-3-KD1细胞克隆形成能力显著下降,差异具有显著的统计学意义(F=44.411,P=0.000).结论:PRL-3基因可促进结直肠癌细胞的增殖.     

Fibroblast growth factor receptor signaling as therapeutic targets in gastric cancer

Fibroblast growth factor receptors(FGFRs) regulate a variety of cellular functions, from embryogenesis to adult tissue homeostasis. FGFR signaling also plays significant roles in the proliferation, invasion, and survival of several types of tumor cells. FGFR-induced alterations, including gene amplification, chromosomal translocation, and mutations, have been shown to be associated with the tumor initiation and progression of gastric cancer, especially in diffuse-type cancers. Therefore, the FGFR signaling pathway might be one of the therapeutic targets in gastric cancer. This review aims to provide an overview of the role of FGFR signaling in tumorigenesis, tumor progression, proliferation, and chemoresistance. We also discuss the accumulating evidence that demonstrates the effectiveness of using clinical therapeutic agents to inhibit FGFR signaling for the treatment of gastric cancer.     

Antagonist of growth hormone-releasing hormone induces apoptosis in LNCaP human prostate cancer cells through a Ca2+-dependent pathway

Antagonists of growth hormone-releasing hormone (GHRH) exert antiproliferative effects directly on cancer cells, which are mediated by the tumoral GHRH receptors. However, the signal transduction pathways involved in antiproliferative effect of GHRH antagonists have not yet been elucidated. We used flow cytometry to investigate whether GHRH antagonist JV-1-38 can induce changes in the cytosolic free Ca2+ concentration leading to apoptosis in LNCaP human prostate cancer cells. JV-1-38 evoked prompt Ca2+ signal in a dose-dependent way (1-10 microM) and induced early stage of apoptosis in LNCaP human prostate cancer cells at a concentration effective in suppression of cell proliferation (10 microM) peaking after 3 h. Unexpectedly, agonist GHRH(1-29)NH2, which elevates cytosolic free Ca2+ concentration in pituitary somatotrophs at nanomolar concentrations, failed to induce Ca2+ signal or apoptosis even at a 10-fold higher concentration (100 microM). However, agonist GHRH(1-29)NH2 inhibited JV-1-38-induced Ca2+ signals in a dose-dependent way without affecting the antagonist-induced apoptosis. Peptides unrelated to GHRH did not induce Ca2+ signals in LNCaP human prostate cancer cells. EDTA (10 mM) or nifedipine (10 microM) significantly reduced the Ca2+ signal and early stage of apoptosis induced by JV-1-38, supporting the view that the increase in intracellular Ca2+ in response to JV-1-38 occurs primarily through extracellular Ca2+ entry through voltage-operated Ca2+ channels. In conclusion, GHRH antagonists activate tumoral GHRH receptors and are able to induce apoptosis in LNCaP human prostate cancer cells through a Ca2+-dependent pathway. Treatment with GHRH antagonists may offer a new approach to the therapy of prostate and other hormone-sensitive cancers.     

丝胶预处理对糖尿病大鼠睾丸生长激素和生长激素受体表达的作用

目的探讨丝胶预处理对糖尿病大鼠睾丸生长激素(GH)和生长激素受体(GHR)表达的作用。方法 30只雄性SD大鼠随机分为3组:正常对照组、糖尿病模型组和丝胶预处理组,每组均为10只。链脲佐菌素(STZ)连续腹腔注射建立糖尿病动物模型,待模型成功建立后,模型组大鼠不再作任何处理;丝胶预处理组大鼠于注射STZ前给予丝胶(2.4 g·kg-1·d-1)灌胃35 d。采用ELISA法检测大鼠血清睾酮和GH水平;分别采用Western印迹和RT-PCR法检测睾丸GH、GHR蛋白和mRNA的表达。结果丝胶预处理可明显抑制糖尿病大鼠血清睾酮水平降低、GH水平升高,睾丸GH表达升高、GHR表达降低(P<0.01,P<0.05)。结论丝胶预处理可通过下调睾丸GH水平、上调睾丸GHR的表达改善糖尿病大鼠的生精功能,发挥对糖尿病生殖功能障碍的预防保护作用。     

生长激素受体基因的研究进展

生长激素(GH)在促进动物生长、发育等代谢过程中起着重要作用。GH发挥生理作用的第一步是与靶细胞膜表面的GH受体(GHR)结合,由GHR介导将信号传入细胞内从而产生一系列生理效应。GHR基因突变可导致空间构象改变,从而影响其功能,使信号不能正常转导,进而影响 GH生理效应的发挥。本文就GHR基因异常与人体生长障碍以及颅面发育的关系作一分析,同时阐述GHR基因研究对人体生长以及颅面发育的生理病理过程的重要意义。     

Inhibitory effect of caffeic acid phenethyl ester on the growth of SW480 colorectal tumor cells involves β-catenin associated signaling pathway down-regulation

AIM: To study the anti-tumor effect of caffeic acid phenethyl ester (CAPE) and the influence of CAPE on β-catenin associated signaling pathway in SW480colorectal cancer (CRC) cells.METHODS: SW480 cells were treated with CAPE at serial concentrations. The proliferative status of cells was measured by methabenzthiazuron (MTT) assay. Cell cycle and cell apoptosis were analyzed using flow cytometry (FCM). Western blotting assay was used to evaluate the protein level of β-catenin, c-myc and cyclinD1.β-catenin localization was determined by indirect immunofluorescence.RESULTS: CAPE displayed a strong inhibitory effect in a significant dose- and time-dependent manner on SW480cell growth. FCM analysis showed that the ratio of G0/G1 phase cells increased, S phase ratio decreased and apoptosis rate increased after SW480 cells were exposed to CAPE for 24 h. Pretreatment of SW480 cells with CAPE significantly suppressed β-catenin, c-myc and cyclinD1protein expression. CAPE treatment was associated with decreased accumulation of β-catenin protein in nucleus and cytoplasm, and concurrently increased its accumulation on the surface of cell membrane.CONCLUSION: CAPE can inhibit SW480 cell proliferation by inducing cell cycle arrest and apoptosis. Decreased β-catenin and the associated signaling pathway target gene expression may mediate the anti-tumor effects of CAPE.     

Therapeutic implications of colon cancer stem cells

Colorectal cancer is the second most common cause of cancer-related death in many industrialized countries and is characterized by a heterogenic pool of cells with distinct differentiation patterns. Recently, the concept that cancer might arise from a rare population of cells with stem cell-like properties has received support with regard to several solid tumors, including colorectal cancer. According to the cancer stem cell hypothesis, cancer can be considered a disease in which mutations either convert no...     

逆转录病毒载体介导IL-6基因修饰大肠癌细胞的抗瘤效应

目的:将外源性 IL-6基因导入大肠癌细胞,建立 IL-6基因表达株,观察 IL-6转基因表达对大肠癌细胞的体内外抑制作用.方法:参照分子克隆技术将构建成功的重组逆转录病毒载体 pZIPIL-6cDNA 转染 PA317包装细胞,以 G418筛选抗性细胞,常规制备重组病毒液并感染大肠癌 HT-29细胞,采用 Northern Blot 分析基因转录水平,ELISA 法和 MTT 显色法检测蛋白表达的量与活性,以细胞生长曲线和集落形成实验以及裸鼠移植瘤实验观察转导株的体内外抑瘤作用。结果:制备了高滴度的重组病毒液(5.1×10~5cfu/ml),建立了稳定表达 IL-6的转导细胞(HT-29IL-6),表达的量与活性分别为1132.5pg/ml/10~5cells 24h 与150U/ml,转导株的细胞群体倍增时间为2.5天,对数生长期在4～7天之间,集落形成率和抑制率分别是2.21%和50%,接种裸鼠皮下的出瘤时间为13.5天,最终瘤体直径在6.5～8.5mm之间,移植瘤标本镜下可见大量凋亡细胞,以上结果与非转导株 HT-29细胞相比,均有显著差异。结论:通过逆转录病毒载体的介导,IL-6基因能稳定整合在靶细胞染色体并进行有效的转录表达,IL-6转基因表达可明显抑制大肠癌细胞的体外增殖和体内移植瘤的形成与发展。     

IQGAP2抑制结肠癌细胞侵袭且通过启动子异常甲基化致基因沉默

目的 探讨在结肠癌细胞系中,含IQ模序GTP酶激活蛋白(IQGAP)2的启动子甲基化状态及IQGAP2对结肠癌细胞侵袭的影响.方法 在人结肠癌RKO细胞株中,采用实时荧光定量聚合酶链反应(RT-PCR)、脱甲基化试剂5-aza-2'-deoxycytidine处理,甲基化特异性聚合酶链反应(MSP)法、甲基化测序检测I...     

Mechanisms underlying aspirin-mediated growth inhibition and apoptosis induction of cyclooxygenase-2 negative colon cancer cell line SW480

AIM： To investigate the effects of aspirin （acetylsalicylic acid） on proliferation and apoptosis of colorectal cancer cell line SW480 and its mechanism. METHODS： Cyclooxygenase （COX）-2 negative colorectal cancer cell line SW480 was treated with aspirin at concentrations of 2.5 mmol/L, 5.0 mmol/L, 10.0 mmol/L for different periods in v/tro. Anti-proliferation effect of aspirin on SW480 was detected by 3-（4,5-dimeth- ylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Cell cycle and apoptosis were observed by flow cytometry （FCM）. Transmission electron microscope （TEM） was used for morphological study. Apoptosis-associated genes were detected by immunohistochemical staining and Western blotting. RESULTS： Aspirin inhibited SW480 proliferation and induced apoptosis in a dose- and time-dependent manner. Treatment with different concentrations of aspirin significantly increased the proportions of cells at the G0/G1 phase and decreased the proportions of cells at the S- and G2/M phases in a concentration-dependent manner. Aspirin not only induced apoptosis but also caused cell necrosis at a high concentration as well. After treatment with aspirin, SW480 cells displayed typically morphological features of apoptosis and necrosis under TEM, and increased the Bcl-2 expression in cells, but the expression of Bax was down regulated. CONCLUSION： Aspirin inhibits proliferation and induces apoptosis of SW480 cells. Its anti-tumor mechanism may arrest cell cycle and shift Bax/Bcl-2 balance in cells.     

人生长激素的体外重组及在原代鼠成肌细胞内的表达

目的 :探讨原代鼠骨骼肌成肌细胞异位表达重组人生长激素 (rhGH)的可行性。方法 :将目的基因人生长激素 (hGH)亚克隆至真核表达载体pcDNA3上 ,构建重组质粒pcDNA hGH。分别用酶切电泳及DNA测序的方法对重组质粒进行鉴定。用阳离子聚合物SofastTM介导的基因转移技术将重组质粒导入体外培养的原代大鼠骨骼肌成肌细胞。收集细胞培养上清液 ,用放射免疫分析 (RIA)的方法检测rhGH。结果 :酶切电泳和DNA测序显示hGHcDNA成功地插入到空载体中 ;rhGH表达持续 3周以上。结论 :该实验成功构建了能在真核细胞内表达的重组质粒pcDNA hGH ,为进一步研究以组织进行的基因治疗奠定了基础。     

姜黄素对人结肠癌细胞SW480作用的体外实验研究

目的 研究姜黄素促进人结肠癌细胞系SW480凋亡的作用.方法 人结肠癌细胞系SW480与不同浓度的姜黄素共孵育48 h,MTT法检测细胞存活率,并用相差显微镜观察细胞形态学改变.用流式细胞术(检测细胞凋亡相关指标Annexin V/PI)和Ho-echst3258染色检测细胞凋亡.结果 姜黄素能够不同程度地抑制人结肠癌细胞系SW480的生长.姜黄素对SW480细胞的IC50(半数抑制浓度)为65 mg/mL.Hoechst3258荧光染色与流式细胞术分析SW480细胞的结果一致.结论 姜黄素可促进SW480细胞凋亡,为姜黄素治疗结肠癌提供依据.     

Effects of insulin-like growth factor 1 on glutathione S-transferases and thioredoxin in growth hormone receptor knockout mice

Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) have been shown to affect processes involved in cellular stress defense, aging, and longevity. This study was designed to identify possible mechanisms of a disrupted GH signaling pathway on stress resistance using growth hormone receptor knockout (GHRKO) mice. GHRKO mice are GH resistant due to the targeted disruption of the GH receptor/binding protein gene, thus preventing GH from binding and exerting its downstream effects. These mice have very low circulating IGF-1 levels and high GH levels, are obese yet insulin sensitive, and live longer than their wild-type controls. Wild-type or GHRKO mice were treated with saline or IGF-1 (WT saline, GHRKO saline, GHRKO IGF-1) two times daily for 7 days. Glutathione S-transferase (GST) activities, proteins, and gene expression were determined. Liver mitochondrial GSTA1, GSTA3, and GSTZ1 proteins were significantly higher in GHRKO when compared to those of WT mice. The 4-hydroxynonenal (4-HNE) GST activity was upregulated in GHRKO mice and was suppressed after IGF-1 administration. Interestingly, thioredoxin (Trx)1, Trx2, thioredoxin reductase (TrxR)1, and TrxR2 messenger RNA (mRNA) levels were significantly higher in the GHRKO as compared to WT mice, and IGF-1 treatment suppressed the expression of each. We also found that glutaredoxin (Grx)2 mRNA and cytosolic Grx activity were higher in GHRKO mice. These results suggest that the detoxification and stress response mechanisms in GHRKO mice are contributed in part by the circulating level of IGF-1.     

利培酮抑制结肠癌细胞株SW480生长的作用机制

目的:探讨利培酮对人结肠癌细胞株SW480生长抑制的作用机制及其相关研究.方法:表皮生长因子和利培酮单独或联合作用于SW480细胞,通过蛋白印迹实验观察蛋白激酶B(protein kinase B,PKB)及细胞外信号调节激酶1/2(extracellular signal-regulated kinase1/2,ERK1/2)磷酸化程度,利用RT-PCR判断细胞因子信号转导抑制因子基因表达水平,利用显微镜及细胞计数方法判断细胞生长情况.结果:利培酮抑制人表皮生长因子诱导的结肠癌细胞株SW480细胞的生长;其机制是通过激活ERK1/2的活性并诱导SOCS3的基因的表达,从而抑制PKB的磷酸化,最终抑制SW480的生长.结论:利培酮具有抑制表皮生长因子对人结肠癌细胞株的生长作用.