EGFR抑制剂通过c-myc途径影响PD-L1在肺癌细胞中的表达

目的:以EGFR抑制剂为介质，研究EGFR/KRAS通路对人非小细胞肺癌A549和H1299细胞中免疫检查点抑制剂PD-L1表达的影响，探讨靶向治疗与免疫治疗联用在相关肿瘤临床治疗中的潜在价值。方法:Western blotting检测A549和H1299细胞经Erlotinib处理后细胞中c-myc的表达量变化； RT-PCR法检测Erlotinib对A549和H1299细胞中c-myc下游基因分化抗原簇47（cluster of differentiation 47，CD47）及PD-L1转录水平的调控，同时平行检测在c-myc基因沉默后，Erlotinib对CD47及PD-L1转录水平的调控；Western blotting检测Erlotinib用量与PD-L1表达的相关性；通过与肿瘤浸润T细胞（tumor infiltrating T cell，TIL-T）共培养，检测Erlotinib影响前后A549和H1299细胞对TIL-T细胞治疗的敏感度。结果:Erlotinib能显著下调c-myc在A549和H1299细胞内的表达量（P<0.01）；c-myc蛋白表达量受Erlotinib影响下调后，PD-L1的转录水平也受到了明显的影响（P<0.01），但Erlotinib对于c-myc沉默的A549和H1299细胞株中CD47及PD-L1的转录水平影响很小（P>0.05）；Erlotinib剂量对A549和H1299细胞中PD-L1的表达量呈现出显著的正相关性，但对c-myc沉默的细胞株影响不大（P>0.05），结果与转录水平一致；Erlotinib处理后，A549和H1299细胞对TIL-T细胞的抵抗能力显著降低，细胞凋亡信号caspase-3激活更加明显。结论:Erlotinib能通过EGFR通路调控c-myc在细胞中的表达水平，进而介导PD-L1表达水平降低，增强TIL-T细胞对A549和H1299细胞的杀伤能力。     

Immunohistochemistry for c-myc and bcl-2 overexpression improves risk stratification in primary central nervous system lymphoma

Overexpression of bcl-2 and c-myc are defining features of double-expressor-lymphoma (DEL) but may also occur separately in patients with primary central nervous system lymphoma (PCNSL). Despite all progress in optimizing treatment regimen, there is lack of sufficient risk stratification models. Here, we first describe the relationship between DEL biology, the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI), treatment response, disease progression, and mortality in PCNSL. In this study, we determined c-myc and bcl-2 status immunohistochemically in samples of 48 patients with newly diagnosed PCNSL and followed these patients for a median interval of 6.2 years. Twelve, 18, and 17 patients harbored none, one, or both DEL features. Corresponding overall response rates after first-line therapy were strongly associated with DEL biology (100%, 42%, and 44% in patients with 0, 1, or 2 DEL features). Patients with one or both DEL features had a 5-fold and 13-fold higher 5-year risk of progression and/or death than patients without DEL features. These associations prevailed after adjusting for the NCCN-IPI. DEL improved the discriminatory capability of the NCCN-IPI (P = .0001). Furthermore, we could show that addition of DEL biology to the NCCN-IPI significantly improved the score's discriminatory potential both toward progression-free survival (increase in Harell's c = 0.15, P = .005) and overall survival (increase in Harell's c = 0.11, P = .029). In conclusion, DEL biology is a strong and simple-to-use predictor of adverse outcome in PCNSL. Addition of DEL to the NCCN-IPI improves its prognostic potential. Disease progression from PCNSL harboring both DEL features is invariably fatal. This defines a novel PCNSL patient subset with a great unmet need for improved therapy.     

小干扰RNA特异性沉默c-myc基因对人胰腺癌SW1990细胞生物学影响

目的 观察小干扰RNA(siRNA)沉默c-myc基因的表达对人胰腺癌细胞株SW1990细胞生物学影响.方法 用siRNA沉默胰腺癌SW1990细胞中c-myc基因,用实时定量反转录聚合酶链反应(RT-qPCR)及Western blot技术检测c-myc mRNA及蛋白的表达量;噻唑蓝(MTT)法检测siRNA沉默c-myc基因对SW1990细胞增殖的影响;膜联蛋白V/碘化丙锭(Annexin V/PI)双染流式细胞术检测沉默c-myc基因细胞凋亡水平;Transwell细胞迁移实验检测siRNA沉默c-myc基因对SW1990细胞迁移能力的影响.结果 靶向c-myc的特异性siRNA可以高效抑制人胰腺癌SW1990细胞c-myc基因表达,在mRNA水平(0.263±0.048)较转染对照质粒组(0.970±0.012)明显降低,c-myc蛋白质表达量及细胞增值率均较转染对照质粒组明显降低;转染后48 h c-myc siRNA组细胞凋亡率为(19.90±2.09)％,明显高于siRNA阴性对照组(4.93±0.25)％和空白对照组(4.40±0.34)％;Transwell实验结果示细胞穿膜数c-myc siRNA组[(34.3±1.2)个]较siRNA-NC组[(68.3±5.8)个]和空白组[(72.3±1.2)个]均明显降低.结论 c-myc siRNA能够显著抑制c-myc基因在人胰腺癌SW1990细胞中的表达,降低细胞的增殖和迁移能力,促进细胞的凋亡.     

基质金属蛋白酶-7和c-myc在口腔鳞状细胞癌中的表达和意义

目的研究基质金属蛋白酶-7(MMP-7)与c-myc在口腔鳞状细胞癌组织中的表达及其意义。方法应用免疫组化EliVisionTM法分别检测MMP-7和c-myc在49例口腔鳞状细胞癌和5例正常口腔黏膜上皮中的表达情况。结果1)MMP-7和c-myc在口腔鳞状细胞癌组织中的阳性表达率分别为83.7%和77.6%。2)在不同病理分级、不同临床分期和有无淋巴转移的口腔鳞状细胞癌组织中MMP-7阳性表达率的差异有统计学意义(P<0.05)。3)在不同病理分级和有无淋巴转移的口腔鳞状细胞癌组织中c-myc阳性表达率的差异亦有统计学意义(P<0.05)。4)口腔鳞状细胞癌组织中MMP-7和c-myc的表达呈正相关(P<0.05)。结论MMP-7和c-myc在口腔鳞状细胞癌组织中均有高表达,在口腔鳞状细胞癌的发病过程中,其高表达具有协同效应,共同促进口腔鳞状细胞癌的发生和发展。     

c-myc在肝细胞肝癌中的表达及其临床意义

目的检测肝细胞肝癌中c-myc蛋白表达情况,研究其与肝癌临床特征的关系,探讨c-myc在肝细胞癌(HCC)发生、发展及转移中的作用。方法采用免疫组织化学技术检测59例肝癌组织及癌旁非癌组织中c-myc蛋白的表达。结果59例肝癌组织中35例c-myc呈阳性表达,阳性率为59.3%。肿瘤组织表达阳性率高于癌旁非癌组织(P<0.05)。c-myc的表达与肝癌的发病年龄,性别,肿瘤大小,分化程度无关(P均>0.05),而与肝癌的转移有关(P<0.05)。应用Kaplan-Meier法制作累积生存曲线并经Log-Rank检验结果显示,c-myc表达阳性与阴性组患者术后累积生存率有显著性差异(P=0.0039)。结论c-myc在肝细胞肝癌中的表达能促进肝癌的发生发展,HCC患者c-myc表达阳性者预后不良,应密切随访。     

c-myc在间变性大细胞淋巴瘤中的表达及其意义

目的 探讨c-myc在系统性间变性大细胞淋巴瘤(ALCL)中蛋白表达和基因异常与临床病理特征、免疫组织分型的关系.方法 选取ALCL患者87例,应用免疫组织化学EnVision法检测c-mvc、间变性淋巴瘤激酶(ALK)、CD3、CD10、CD20、CD30、EMA的蛋白表达情况;应用荧光原位杂交(FISH)技术检测c-myc和ALK基因异常情况;统计分析c-myc蛋白表达和基因异常与各临床病理参数间的关系.结果 免疫组织化学结果:87例ALCL中,ALK阳性者54例(62.1％),c-myc阳性者27例(31.0％),c-myc和ALK蛋白联合表达20例(23.0％).c-myc蛋白表达率、c-myc和ALK蛋白联合表达率随ALCL临床分期的增加而升高,且在国际预后指数(IPI)高危组中表达率高于低危组(P＜0.05).FISH检测结果:87例ALCL中,50例(57.5％)发现ALK基因的易位,19例(21.8％)发现ALK基因的多拷贝.所有患者均未发现c-myc基因的易位,但19例(21.8％)检测到c-myc基因的多拷贝.c-myc基因多拷贝的发生率在ALK蛋白阳性和阴性组中差异无统计学意义(P＞0.05),在c-myc蛋白阳性和阴性组中发生率差异有统计学意义(P＜0.05),在IPI高危组中发生率高于低危组(P＜0.05).结论 c-myc蛋白表达及基因异常与ALCL临床分期、IPI相关,可作为判断ALCL恶性程度和预测预后的指标.     

The role of XPB in cell apoptosis and viability and its relationship with p53, p21 and c-myc in hepatoma cells

BACKGROUND: Accumulation of DNA damage has been implicated in hepatocarcinogenesis. XPB plays a pivotal part in repairing damaged DNA. However, up to now, the biological effect of XPB on hepatoma cells remains elusive. MATERIALS AND METHODS: Here, we investigated the role of XPB in the apoptosis and the viability of hepatoma cells by using the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labelling and cell viability assay; we also investigated their relationship with p53, p21(waf1/cip1) and c-myc by using the RT-PCR and Western blot. RESULTS: Compared with the control cells HepG2/pcDNA3.1 or HepG2, XPB-transfected HepG2 cells (HepG2/pcDNA3.1-XPB) displayed lower viability, weaker activity and higher apoptosis index. At the same time, an increased expression of p21(waf1/cip1) mRNA, protein and p53 protein in addition to a decreased expression of c-myc mRNA and protein were detected in HepG2/pcDNA3.1-XPB cells. CONCLUSIONS: Our results indicated that XPB could inhibit the proliferation of hepatoma cells and had a positive effect on the expression of p53 and p21(waf1/cip1) but a negative effect on c-myc.     

Apoptosis and its pathway in X gene-transfected HepG2 cells

AIM: To investigate the effect of hepatitis B virus (HBV) X gene on apoptosis and expressions of apoptosis factors in X gene-transfected HepG2 cells. METHODS: The HBV X gene eukaryon expression vector pcDNA3-X was transiently transfected into HepG2 cells by lipid-media transfection. Untransfected HepG2 and HepG2 transfected with pcDNA3 were used as controls. Expression of HBx in HepG2 was identified by RT-PCR. MTT and TUNEL were employed to measure proliferation and apoptosis of cells in-three groups. Semi-quantified RT-PCR was used to evaluate the expression levels of Fas/FasL, Bax/Bcl-xL, and c-myc in each group. RESULTS: HBV X gene was transfected into HepG2 cells successfully. RT-PCR showed that HBx was only expressed in HepG2/pcDNA3-X cells, but not expressed in HepG2 and HepG2/pcDNA3 cells. Analyzed by MTT, cell proliferation capacity was obviously lower in HepG2/pcDNA3-X cells (0.08910±0.003164) than in HepG2(0.14410±0.004927) and HepG2/pcDNA3 cells (0.12150±0.007159) (P<0.05 and P<0.01). Analyzed by TUNEL, cell apoptosis was much more in HepG2/pcDNA3-X cells (980/2 000) than HepG2 (420/2 000), HepG2/pcDNA3 cells (520/2 000) (P<0.05 and P<0.01). Evaluated by semi-quantified RT-PCR, the expression level of Fas/FasL was significantly higher in HepG2 cells transfected with HBx than in HepG2 and HepG2/ pcDNA3 cells (P<0.05 and P<0.01). Bax/Bcl-xL expression level was also elevated in HepG2/pcDNA3-X cells (P<0.05 and P<0.01). Expression of c-myc was markedly higher in HepG2/pcDNA3-X cells than in HepG2 and HepG2/pcDNA3 cells (P<0.05 and P<0.01). CONCLUSION: HBV X gene can impair cell proliferation capacity, improve cell apoptosis, and upregulate expression of apoptosis factors. The intervention of HBV X gene on the expression of apoptosis factors may be a possible mechanism responsible for the change in cell apoptosis and proliferation.