Genetic polymorphisms in translesion synthesis genes are associated with colorectal cancer risk and metastasis in Han Chinese

Translesion synthesis (TLS) polymerases have low processivity and fidelity compared with replicative polymerases. Defective function of TLS polymerases result in chromosome instability. The aim of this study was to evaluate the effects of TLS genes on susceptibility and metastasis in colorectal cancer (CRC). Four single nucleotide polymorphisms (SNPs) (rs462779, rs11153292, rs373572 and rs2233004) of TLS genes were genotyped in the pilot cohort consisted of 516 patients with CRC and 503 controls, and then replicated in the replication cohort of 421 cases and 446 controls. The genotype frequencies of rs462779 and rs373572 were significantly different between CRC patients and controls in both two cohorts, even after it was adjusted by age, gender and smoking status. Stratified analysis showed that rs462779 and rs373572 were significantly associated with both colon and rectum cancer. In patients with metastatic CRC, the frequency of AA genotype of rs373572 was significantly increased as compared with those without metastasis CRC (P=0.001). Furthermore, rs462779 and rs373572 exhibited remarkably cumulative effect on the risk of CRC (trend P value=0.001). No significant difference was observed between other SNPs and CRC. These results suggest that polymorphisms in TLS genes are associated with susceptibility to CRC in Chinese and might be a novel biomarker for the predication of metastasis risk of CRC.     

Analyses of chromosome copy number and expression level of four genes in the ciliate Chilodonella uncinata reveal a complex pattern that suggests epigenetic regulation

Exogenous wild-type p53 (wt-p53) tumor suppression increases the sensitivity of tumor cells to radiotherapy and chemotherapy. An iodized oil emulsion was used as a p53 vector for intra-arterial gene delivery to treat hepatic tumors. Whether the chemotherapeutic agent or the iodized oil affects exogenous wt-p53 activity remains poorly understood. In the present study, the early therapeutic response of rAd/p53, combined with 5-fluorouracil (5-FU) or with iodized oil, was observed in a human colon cancer model. Allograft models in 82 nude mice with human colon carcinoma SW480 were divided randomly into four groups and administered with physiologic saline, rAd/p53, rAd/p53+5-FU, and rAd/p53+iodized oil by intratumoral injection. At 24, 48, 72, 120, and 168 h after treatment, p53 expression, the Ki-67 index (KI), and the degree of tumor necrosis were assessed. The p53 expression and tumor necrosis in the therapeutic groups were higher than those in the control group. p53 expression reached its peak at 120 h in the rAd/p53 group, at 72 h in the rAd/p53+5-FU group, and at 48 h in the rAd/p53+iodized oil group. The p53 expression in the rAd/P53+5-FU group and the iodized oil group was significantly higher than those in the rAd/P53 group at 24 and 48 h. The results revealed that tumor necrosis is positively correlated with p53 expression. The KI of the rAd/p53+5-FU group increased significantly at 24 h. 5-FU and iodized oil increase the anticancer effect of rAd/p53, and 5-FU combined with rAd/p53 has a synergistic anticancer effect.     

Signal transduction in receptor for advanced glycation end products (RAGE): solution structure of C-terminal rage (ctRAGE) and its binding to mDia1

The receptor for advanced glycation end products (RAGE) is a multiligand cell surface macromolecule that plays a central role in the etiology of diabetes complications, inflammation, and neurodegeneration. The cytoplasmic domain of RAGE (C-terminal RAGE; ctRAGE) is critical for RAGE-dependent signal transduction. As the most membrane-proximal event, mDia1 binds to ctRAGE, and it is essential for RAGE ligand-stimulated phosphorylation of AKT and cell proliferation/migration. We show that ctRAGE contains an unusual α-turn that mediates the mDia1-ctRAGE interaction and is required for RAGE-dependent signaling. The results establish a novel mechanism through which an extracellular signal initiated by RAGE ligands regulates RAGE signaling in a manner requiring mDia1.     

WT1 CpG islands methylation in human lung cancer: A pilot study

Background

CpG island hypermethylation of gene promoters and regulatory regions is a well-known mechanism of epigenetic silencing of tumor suppressors and is directly linked to carcinogenesis. Wilm’s tumor gene (WT1) is a tumor suppressor protein involved in the regulation of human cell growth and differentiation and a modulator of oncogenic K Ras signaling in lung cancer. Changes in the pattern of methylation of the WT1 gene have not yet been studied in detail in human lung cancer. In this study we compared the methylation profile of WT1 gene in samples of neoplastic and non-neoplastic lung tissue taken from the same patients.

Methods

DNA was extracted from neoplastic and normal lung tissue obtained from 16 patients with non small cell lung cancer (NSCLC). The methylation status of 29 CpG islands in the 5′ region of WT1 was determined by pyrosequencing. Statistical analysis was carried out by T test and Mann Whitney test.

Results

The mean percentage of methylation, considering all CpG islands of WT1 in the neoplastic tissues of the 16 NSCLC patients, was 16.2 ± 3.4, whereas in the normal lung tissue from the same patients it was 5.6 ± 1.7 (p < 0.001). Adenocarcinomas presented higher methylation levels than squamous cell carcinomas (p < 0,001).

Conclusions

Methylation of WT1 gene is significantly increased in NSCLC. Both histotype and exposure to cigarette smoke heavily influence the pattern of CpG islands which undergo hypermethylation.     

Overexpression of polo-like kinase 1 and its clinical significance in human non-small cell lung cancer

Polo-like kinase 1 is a serine/threonine kinase which plays an essential role in mitosis and malignant transformation. The aim of this study was to investigate the prognostic significance of polo-like kinase 1 expression and determine its possibility as a therapeutic target in non-small cell lung cancer. Semi-quantitative RT-PCR assay was performed to detect polo-like kinase 1 mRNA expression in non-small cell lung cancer cells or tissues. Immunohistochemistry was performed to detect polo-like kinase 1 protein expression in 100 non-small cell lung cancer tissue samples, and the associations of polo-like kinase 1 expression with clinicopathological factors or prognosis of non-small cell lung cancer patients were evaluated. RNA interference was employed to inhibit endogenous polo-like kinase 1 expression and analyzed the effects of polo-like kinase 1 inhibition on the malignant phenotypes of non-small cell lung cancer cells including growth, apoptosis, radio- or chemoresistance. Also, the possible molecular mechanisms were also investigated. The levels of polo-like kinase 1 mRNA expression in non-small cell lung cancer cell lines or tissues were significantly higher than those in normal human bronchial epithelial cell line or corresponding non-tumor tissues. High polo-like kinase 1 expression was significantly correlated with advanced clinical stage, higher tumor classification and lymph node metastasis of non-small cell lung cancer patients (P = 0.001, 0.004 and 0.001, respectively). Meanwhile, high polo-like kinase 1 protein expression was also an independent prognostic molecular marker for non-small cell lung cancer patients (hazard ratio: 2.113; 95% confidence interval: 1.326-3.557; P = 0.017). Polo-like kinase 1 inhibition could significantly inhibit in vitro and in vivo proliferation, induce cell arrest of G₂/M phase and apoptosis enhancement in non-small cell lung cancer cells, which might be activation of the p53 pathway and the Cdc25C/cdc2/cyclin B1 feedback loop. Further, inhibition of polo-like kinase 1 could enhance the sensitivity of non-small cell lung cancer cells to taxanes or irradiation. Thus, polo-like kinase 1 might be a prognostic marker and a chemo- or radiotherapeutic target for non-small cell lung cancer.     

首都医科大学宣武医院神经内科高级研修培训模式的探讨分析

医学进修是提高医务人员综合素质的重要途径.宣武医院神经内科依托于首都医科大学神经病学系开展了”神经内科高级研修培训班”,选取高素质的医师进行个体化培训.已培训学员112名,其中16人成为医院或当地神经内科系统学科带头人,35人成为学术骨干;建立专科专病门诊(中心)38个,建立疑难病会诊中心21个;申请省市级课题36项,国家级课题18项.极大的提高了当地的临床、科研和学术水平,取得了显著的成效,值得推广和借鉴.     

鸦胆子油乳联合NP 方案治疗晚期非小细胞肺癌的临床疗效观察

目的:观察鸦胆子油乳联合NP方案化疗与单纯NP方案化疗对晚期肺小细胞癌患者的疗效、生活质量等因素的影响。方法:将154例患有晚期非小细胞肺癌患者随机分为两组:治疗组,在NP方案化疗基础上使用鸦胆子油乳治疗;对照组,单纯接受NP方案化疗。对154例患者追踪3个月,观察并比较患者的疗效、体质量、生活质量、毒副反应等方面的差异。结果:在NP方案化疗基础上使用鸦胆子油乳治疗在患者疗效评价方面与单纯NP方案化疗相比不具有统计学差异(P>0.05);在提高患者体质量、改善患者临床症状和生活质量等方面均优于单纯NP方案化疗(P<0.05);在化疗所引发的白细胞、血红蛋白和血小板降低等部分毒副反应发生率方面低于单纯NP方案化疗组(P<0.05)。结论:鸦胆子油乳联合NP方案化疗治疗晚期非小细胞肺癌不仅可以起到化疗增效的作用,而且能够明显提高患者生活质量,有效的改善临床症候,降低化疗引发的毒副反应,这一联合治疗方案可以在临床治疗中广泛推广。     

糖基化终末产物（AGEs）诱导下SOCS基因在肾小管上皮细胞中的表达及意义

目的观察SOCS-1、SOCS-3在肾小管上皮细胞（HKC）中的基础表达及在糖基化终末产物（AGEs）诱导下的表达及意义。方法体外培养HKC细胞,随机分为正常对照组、AGEs组,倒置显微镜观察细胞形态学改变,采用流式细胞术,免疫细胞化学和检测SOCS-1、SOCS-3蛋白表达,RT-PCR法检测HKCSOCS-1、SOCS-3 mRNA表达。结果与正常组比较,AGES诱导的肾小管上皮细胞发生形态学改变;免疫细胞化学、流式细胞学发现SOCS-1、SOCS-3表达以胞浆为主,散在胞核表达;12、24、48hSOCS-1、SOCS-3蛋白表达AGEs组均高于正常对照组,差异有统计学意义,其中SOCS-1以12h表达量最大,SOCS-3以24h表达最高,RT-PCR检测SOCS-3 mRNA表达量,AGEs组高于正常组,差异有统计学意义。结论SOCS-1、SOCS-3在正常肾小管上皮细胞中有基础表达,AGEs可诱导肾小管上皮细胞SOCS-1、SOCS-3表达上调,为我们进一步研究SOCS基因与糖尿病肾病的关系提供了理论依据。     

A cell-based high-throughput screen for epidermal growth factor receptor pathway inhibitors

Epidermal growth factor receptor (EGFR) is a valid drug target for development of target-based therapeutics against non-small-cell lung cancer. In this study, we established a high-throughput cell-based assay to screen for compounds that may inhibit EGFR activation and/or EGFR-mediated downstream signaling pathway. This drug screening platform is based on the characterization of an EGFR-transfected 32D cell line (32D-EGFR). The expression of EGFR in 32D cells allowed cell proliferation in the presence of either epidermal growth factor (EGF) or interleukin 3 (IL-3) and provided a system for both screening and counterscreening of EGFR pathway-inhibitory compounds. After the completion of primary and secondary screenings in which 32D-EGFR cells were grown under the stimulation of either EGF or IL-3, 9 of 20,000 compounds were found to selectively inhibit the EGF-dependent proliferation, but not the IL-3-dependent proliferation, of 32D-EGFR cells. Subsequent analysis showed that 3 compounds of the 9 initial hits directly inhibited the kinase activity of recombinant EGFR in vitro and the phosphorylation of EGFR in H1299 cells transfected with EGFR. Thus, this 32D-EGFR assay system provides a promising approach for identifying novel EGFR and EGFR signaling pathway inhibitors with potential antitumor activity.