慢病毒转染胸苷磷酸化酶基因增强5'-脱氧氟尿苷抗结肠癌细胞活性

目的 探讨5’-脱氧氟尿苷(5’-DFUR)和氟尿嘧啶(5-Fu)对人结肠癌细胞株HT29和LS174T转染胸苷磷酸化酶(TP)基因前后抗癌效应的变化.方法 构建包含TP基因的慢病毒载体,转染结肠癌细胞株HT29和LS174T.传代5代后,以流式细胞术检测转染效率.免疫组织化学染色和Western blot检测转染TP基因前后HT29和LS174T细胞中TP蛋白的表达,逆转录聚合酶链反应(RT-PCR)法检测细胞中TP mRNA的表达水平,四唑氮化合物法检测5’-DFUR和5-Fu对转染TP基因前后细胞株的半数抑制浓度(IC50),高效液相色谱(HPLC)法检测HT29和LS174T在细胞转染TP基因前后转化5'-DFUR为5-Fu的水平.结果 转染TP基因的HT29和LS174T细胞传代5代后,转染效率稳定在约95.0％.转染TP基因的HT29和LS174T细胞中TP表达阳性,而野生型细胞和仅转染病毒载体细胞中TP表达阴性;Westem blot结果显示,HT29和LS174T细胞中TP蛋白的表达明显增强.RT-PCR结果显示,转染TP基因的HT29和LS174T细胞中TP mRNA的相对表达水平分别为8.45 ±0.15和2 615.02±253.97,与野生型细胞比较,差异均有统计学意义(均P＜0.01).5 '-DFUR对转染TP基因的HT29-TP细胞和野生型细胞的IC50分别为(14.33±0.74) μmol/L和(707.66±5.66) μmol/L(P ＜0.05);对转染TP基因的LS174T-TP细胞和野生型细胞的IC50分别为(0.59±0.11)μmol/L和(239.20 ±21.83) μmol/L(P＜0.05).5-Fu对转染TP基因的HT29-TP细胞和野生型细胞的IC5o分别为(5.42±0.75) μmol/L和(14.19 ±0.97) μmol/L(P ＜0.05);对转染TP基因的LS 174T-TP细胞和野生型细胞的IC50分别为(4.41±0.96) μmol/L和(16.42±2.12) μmol/L(P＜0.05).转染TP基因后的HT29和LS174T细胞培养基中,则检出大量转化的5-Fu,较转染前分别增加了12.2 ～23.6倍,差异均有统计学意义(均P＜0.01).在细胞裂解液中也检出有少量5-Fu,但其水平仅相当于培养基中的0.9％ ～4.2％.结论 以慢病毒为载体将TP基因转染至人结肠癌细胞HT29和LS714T,能得到转染效率高和稳定传代的细胞株,并且2株细胞的TP蛋白和TP mRNA的表达水平明显增高.转染后在培养基中转化的5-Fu水平明显增高,使5-Fu和5’-DFUR对HT29和LS714T细胞的抗癌作用明显增强,但5’-DFUR增强效果更加明显.     

胸苷磷酸化酶表达与结直肠癌关系研究进展

胸苷磷酸化酶(thymidine phosphorylase, TP)是嘧啶核苷合成与分解过程中的一个关键酶。目前认为TP与血小板源性内皮细胞生长因子(platelet-derived endothelial cell growth factor, PD-ECGF)具有同源性, 其诱导血管形成和抗凋亡的作用与结直肠癌的生长、转移密切相关。同时TP也是使5'-脱氧氟尿苷(5'-deoxy-5-fluorouridine, 5'-DFUR)等(5-fluorouracil, 5-FU)前体药物转化为5-FU的关键酶, 其活性与结直肠癌细胞对氟尿嘧啶类药物的敏感性及靶向治疗密切相关。因TP在肿瘤的生长、转移、治疗和预后方面均有重要作用, 阐明其表达机制具有重要意义。本文将对近年TP在结直肠癌中的表达与肿瘤血管新生及与激活5'-DFUR发挥细胞毒作用、治疗结直肠癌的研究进展进行综述。      

CD与bcl-Xs基因联合转染卵巢癌细胞株对5-氟胞嘧啶作用的影响

目的　了解自杀基因胞嘧啶脱氨酶基因 (cytosinedeaminase ,CD)及其前药 5 氟胞嘧啶 (5 fluorucytosine,5 FC)和bcl Xs基因转移联合作用对卵巢癌细胞株生长的影响。方法　以复制缺陷型腺病毒为载体将CD基因和bcl Xs基因体外转染大鼠卵巢癌细胞株NUTU 19细胞 ,加入含 5 FC的培养基。MTT法检测培养细胞吸光度值 ,计算细胞存活率。结果　单一bcl Xs基因转移及单一CD /5 FC系统作用对NUTU 19细胞的生长抑制作用均随病毒滴度的增加而增大 ;将两者联合作用于NU TU 19细胞 ,其生长抑制率比两者单独使用时的生长抑制率之和更高 ,表现为协同效应 (P <0 .0 0 0 1)。结论　CD /5 FC系统与bcl Xs基因转移联合使用对NUTU 19细胞的生长抑制具有协同作用。     

脱氧氟尿苷术前口服化疗对胃癌组织PD-ECGF表达的影响及意义

[目的]了解术前脱氧氟尿苷口服化疗对胃癌组织血小板衍化内皮细胞生长因子(PD-ECGF)表达的影响及意义。[方法]胃癌患者术前随机分为三组:组1:氟铁龙800mg/d～1200mg/d,3～5天;组2:5-Fu0.5+CF200mg/d静脉滴注,3～5天;组3:对照组。化疗结束后第1～2天行手术。切除标本采用免疫组化法及TUNEL法检测胃癌组织中PD-ECGF表达率及细胞凋亡指数(AI)。[结果]全组PD-ECGF阳性率为51.9%。PD-ECGF表达率与根治切除、肿瘤侵犯深度、淋巴结转移、有无远处转移及UICC分期无关(P>0.05)。组1中PD-ECGF表达率(28.6%,4/18)明显低于组2(56.3%,9/16)及对照组(65.0%,13/20)(P=0.023)。AI在组1为14.39±9.49,组2为14.11±9.68,明显高于对照组(6.88±7.37)。在PD-ECGF阳性组中肿瘤细胞凋亡指数(8.12±5.19)明显低于阴性组(14.69±11.23),差异有显著性(F=7.409,P=0.009)。随访截止至2006年12月31日,50例获得随访,总的1、2、3、5年生存率分别为78.0%、58.8%、48.7%、48.7%。PD-ECGF阳性患者1、2、3、5年生存率分别为76.0%、56.0%、47.7%、47.7%;低于阴性组的80.0%、60.0%、52.0%、52.0%,但差异无显著性(χ2=0.177,P=0.674)。[结论]术前脱氧氟尿苷口服化疗可降低胃癌组织中PD-ECGF表达率。PD-ECGF阳性表达患者的肿瘤细胞凋亡指数低于阴性组,倾向预后不良。     

5-脱氧杂氮胞苷对肝癌细胞分泌exosomes及其免疫相关分子的影响

目的 探讨5-脱氧杂氮胞苷(5-Aza-Cda)对肝癌细胞分泌exosomes及其负载的肿瘤相关抗原和免疫相关分子含量的影响.方法 采用离心超滤联合蔗糖密度梯度离心方法,分离和纯化经5-Aza-CdR处理和未处理的HepG2和Hep3B肝癌细胞释放的exosomes,并对exosomes进行计数和蛋白定量测定.采用免疫电镜和Western blot技术,观察exosomes表达HSP70、HLA-Ⅰ和NY-ESO-1蛋白的变化;以逆转录聚合酶链反应(RT-PCR)检测5-Aza-CdR处理前后HepG2和Hep3B细胞野生型p53基因mRNA的表达.结果 经5-Aza-CdR处理后,HepG2和Hep3B细胞p53基因mRNA表达较未处理组均明显增加,exosomes数量和蛋白含量均较未处理组显著增加(P<0.05).经免疫电镜和Western blot鉴定,exosomes上均附载有HSP70、HLA-Ⅰ和NY-ESO-1蛋白,且两种细胞来源的exosomes经5-Aza-CdR处理后,HSP70、HLA-Ⅰ和NY-ESO-1蛋白含量均明显增加.结论 DNA甲基转移酶抑制剂5-Aza-CdR可使肝癌细胞分泌更多数量的exosomes,增加exosomes中的免疫相关分子含量,其机制可能与p53基因上调和DNA去甲基化有关.     

γ干扰素通过诱导 PD-ECGF/TP表达增强去氧氟尿苷和 5-FU对膀胱癌细胞 RT4的杀伤作用

背景与目的:血小板衍化内皮细胞生长因子 /胸苷磷酸化酶 (platelet-derived endothelial cell growth factor/thymidine phosphorylase,PD-ECGF/TP)是去氧氟尿苷和 5 氟尿嘧啶在体内转化成活性抗癌物质的重要酶,它受到白细胞介素-1、γ干扰素等细胞因子的调节.本研究旨在探讨γ干扰素对 RT4膀胱癌细胞 PD-ECGF/TP表达的调节作用及其与去氧氟尿苷和 5 氟尿嘧啶抗癌作用的关系.方法:分别用 RT-PCR和 Western blot检测膀胱癌细胞 RT4中 PD-ECGF/TP mRNA和蛋白质的表达, MTS[3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymetho-xyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium,inner salt]法测定去氧氟尿苷和 5 氟尿嘧啶对 RT4膀胱癌细胞的细胞毒作用.结果:γ干扰素能增强 RT4膀胱癌细胞 PD-ECGF/TP mRNA和蛋白质的表达,γ干扰素与去氧氟尿苷和 5 氟尿嘧啶分别合用,能使去氧氟尿苷和 5 氟尿嘧啶的 IC50分别从( 9.7± 0.2) mmol/L和 (130.0± 21.2)μ mol/L降至 (3.7± 0.9)mmol/L和 (49.3± 18.4)μ mol/L(P< 0.01).结论:γ干扰素通过诱导 RT4膀胱癌细胞表达 PD-ECGF/TP增强去氧氟尿苷和 5 氟尿嘧啶的抗癌作用,提示联合应用γ干扰素和去氧氟尿苷或 5 氟尿嘧啶可能提高膀胱癌的化疗效果.     

5-FU对小鼠乳腺癌4T1细胞株中肿瘤干细胞样细胞的富集作用

目的:探讨以氟尿嘧啶(5-fluorouracil,5-FU)处理并通过荷瘤小鼠模型体内传代的方法富集乳腺癌干细胞样细胞的可行性,为靶向肿瘤干细胞治疗奠定基础.方法:以乳腺癌细胞株4T1皮下接种小鼠制备荷瘤模型,以一定剂量5-FU腹腔注射4周;处死小鼠后取肿瘤组织制成细胞悬液,并接种小鼠制备下一代小鼠荷瘤模型,5-FU处理及再次传代方法同上,共传4代.对照组小鼠给予生理盐水注射,其余处理同模型组.流式细胞术检测各代肿瘤组织中CD44+ CD24-/low细胞比例,Hoechast 33342染色法检测侧群(side population,SP)细胞的比例,免疫组化法检测CD55和ALDH1蛋白的表达,倒置显微镜观察乳腺癌细胞微球体的形成,小鼠致瘤实验检测不同肿瘤细胞的致瘤能力.结果:各代对照组小鼠模型肿瘤组织中CD44+CD24-/low细胞比例为(11.5±0.9)％,SP细胞比例为(9.7±1.3)％,ALDH1表达阴性,CD55强阳性表达细胞数为(0.6±0.3)％,乳腺癌细胞微球体比例为(0.5±0.2)％;5-FU处理组4代小鼠模型肿瘤组织中CD44+ CD24-/low细胞比例分别为(49.8±1.2)％、(56.8％±1.7)％、(66.4±1.5)％、(69.0±1.6)％,SP细胞比例分别为(25.0±1.2)％、(42.6±2.8)％、(58.4±2.1)％、(61.3±2.6)％,ALDH1阳性表达细胞比例为(3.8±0.7)％、(14.1±2.4)％、(25.2±3.1)％、(27.5±2.7)％,CD55强阳性细胞比例为(7.8±1.6)％、(10.1±2.0)％、(15.6±1.4)％、(17.3±1.9)％,乳腺癌细胞微球体形成比例为(5.9±0.4)％;两组各相应指标之间差异均具有统计学意义(P＜0.05或P＜0.01).5-FU作用后富集了肿瘤干细胞的第3代肿瘤细胞的致瘤作用显著强于对照组细胞(P＜0.05).结论:5-FU作用并通过荷瘤小鼠体内传代能够富集小鼠乳腺癌4T1细胞株中的肿瘤干细胞样细胞.     

The treatment of mouse colorectal cancer by oral delivery tumor-targeting Salmonella

Systemic administration of Salmonella to tumor-bearing mice leads to its preferential accumulation in tumor sites, the enhancement of host immunity, and the inhibition of tumor growth. However, the underlying mechanism for Salmonella-induced antitumor immune response via oral delivery remained uncertain. Herein, we used mouse colorectal cancer (CT26) as tumor model to study the therapeutic effects after oral delivery of Salmonella. When orally administered into tumor-bearing mice, Salmonella significantly accumulated in the tumor sites, inhibited tumor growth and extended the survival of mice. No obvious toxicity was observed during orally administered Salmonella by examining body weight and inflammatory cytokines. As indoleamine 2, 3-dioxygenase 1 (IDO) is a crucial mediator for tumor-mediated immune tolerance, we examined the expression of IDO. We demonstrated that Salmonella inhibited IDO expression in mouse cancer cells. Furthermore, immunohistochemical studies of the tumors revealed the infiltration of neutrophils and T cells in mice treated with Salmonella. In conclusion, our results indicate that Salmonella exerts its tumoricidal effects and stimulates T cell activities by inhibiting IDO expression. Oral delivery of Salmonella may, represent a potential strategy for the treatment of tumor.     

Comprehensive analysis of differentially expressed genes reveals the promotive effects of UBE2T on colorectal cancer cell proliferation

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Via analysis using The Cancer Genome Atlas database, the present study identified 1,835 genes that were differentially expressed in CRC, including 811 upregulated and 1,024 downregulated genes. Enrichment analyses using the Database for Annotation, Visualization and Integrated Discovery tool revealed that these differentially expressed genes were associated with the regulation of CRC progression by modulating multiple pathways, such as ‘Cell Cycle, Mitotic’, ‘DNA Replication’, ‘Mitotic M-M/G1 phases’ and ‘ATM pathway’. To identify the key genes in CRC, protein-protein interaction (PPI) network analysis was performed and the hub modules in upregulated and downregulated PPI networks were identified. Ubiquitin-conjugating enzyme E2 T (UBE2T), a member of the E2 family, was identified to be a key regulator in CRC. To the best of our knowledge, the present study was the first to demonstrate that UBE2T expression was upregulated in CRC samples compared with normal tissues. Kaplan-Meier analysis revealed that higher expression levels of UBE2T were associated with worse prognosis compared with lower UBE2T expression levels in CRC. Additionally, the present study demonstrated that knockdown of UBE2T inhibited CRC cell proliferation. Flow cytometry assays revealed that UBE2T knockdown induced cell cycle arrest at G₁ phase and apoptosis in vitro. These results suggested that UBE2T may be a novel potential biomarker for CRC.     

Everolimus combined with 5-aza-2-deoxycytidine generated potent anti-tumor effects on ovarian clear cell cancer stem-like/spheroid cells by inhibiting the COL6A3-AKT-mTOR pathway

Ovarian clear cell cancer stem-like/spheroid cells (OCCCSCs) were associated with recurrence, metastasis, and chemoresistance in ovarian clear cell carcinoma (OCCC). We evaluated the anti-tumor effects of 5-aza-2-deoxycytidine (5-aza-dC) combined with everolimus (RAD001) on human OCCC. We investigated parental OCCCSCs and paclitaxel-resistant cell lines derived from OCCCSCs in vitro and in vivo. A Western blot analysis showed that the 5-aza-dC and RAD001 combination therapy was associated with the COL6A3-AKT-mTOR pathway. The OCCCSCs expressed high levels of stemness markers: CD117, ALDH1, NANOG, OCT4, and CD133. The 5-aza-dC and RAD001 combination inhibited proliferation and survival with up to 100-fold more potency in OCCCSCs compared to OCCC cells. This combination showed significant anti-tumor activity; it preferentially diminished OCCCSC stemness levels and spheroid numbers in vitro. Limiting dilution assays showed that OCCCSCs possessed tumor-initiating capacity. The 5-aza-dC and RAD001 combination significantly enhanced the inhibition of tumor growth compared to the 5-aza-dC or RAD001 alone. OCCCSCs showed higher expression levels of COL6A3, phospho-AKT, phospho-mTOR, and phospho-Rictor compared to OCCCs. Silencing COL6A3 or abolishing the phospho-AKT-mTOR-Rictor pathway with 5-aza-dC and RAD001 treatment further enhanced OCCCSC apoptosis and reduced OCCCSC stemness. In conclusion, 5-aza-dC combined with RAD001 effectively controlled OCCC and OCCCSC growth by inhibiting the COL6A3-AKT-mTOR pathway.     

不同化疗方案对裸鼠MCF-7乳腺癌移植瘤PCNA和Bcl-2表达的影响

目的：研究不同化疗方案对乳腺癌组织PCNA和Bcl-2的影响,探讨二者与化疗的关系及评价疗效的价值。方法：制备MCF-7乳腺癌荷瘤裸鼠模型,化疗后观察移植瘤病理组织学疗效,用免疫组化SP法显示乳腺癌组织PCNA和Bcl-2表达情况。结果：（1）各化疗组瘤组织PCNA表达显著低于对照组（P〈0．05）,且NP、TP和Xeloda组显著低于CMF、CAF组（P〈0．05）。PCNA表达与病理疗效显著相关（P=0．001）。（2）CAF、NP、TP和Xeloda化疗组Bcl-2蛋白表达显著高于对照组（P〈0．05）,且TP组显著高于CMF、CAF组（P〈0．05）。Bcl-2表达与病理疗效无显著相关性（P=0．093）。结论：化疗可降低乳腺癌组织PCNA表达,并增强Bcl-2的表达,且不同化疗方案对二者影响的差异有显著性。PCNA可作为评价乳腺癌化疗效果的参考指标,对选择化疗方案可能有指导意义。     

人参皂甙 Rh2 联合顺铂对食管癌细胞的杀伤作用

目的：体外观察低剂量人参皂甙Rh2（ginsenoside Rh2,GS-Rh2）对抗肿瘤药顺铂（cisplatin,DDP）杀伤人食管癌细胞株Eca109的影响,并探讨其可能的作用机制.方法：人食管癌细胞Eca109经培养符合条件后,分别加用0.3μg/ml DDP（A组）、20μmol/ml GS-Rh2（B组）、0.3μg/ml DDP＋20μmol/ml GS-Rh2（C组）、对照组（D组）处理48小时.流式细胞仪检测各组细胞凋亡率和死亡率.高效液相色谱检测各组细胞内DDP的药物浓度.蛋白质印迹法检测各组细胞中p53表达.结果：细胞凋亡率和死亡率C组显著高于A、B两组（P＜0.05）;C组细胞内DDP的药物浓度显著高于A组细胞（P＜0.05）;C组细胞p53表达水平低于A组（P＜0.05）.结论：体外低剂量GS-Rh2能增强DDP对人食管癌细胞Eca109的杀伤作用,其作用机制可能与降低细胞内p53表达有关.