目的:探讨DNA聚合酶Iota(Pol(ι))与食管鳞癌淋巴结转移的关系.方法:采用实时荧光定量PCR方法检测Pol(ι)基因在食管鳞癌组织中的表达,并使用Mann-Whitney U检验方法分析Pol(ι)与食管鳞癌淋巴结转移之间的关系;利用免疫组织化学染色法检测Pol(ι)及Nm23蛋白在食管鳞癌组织中的表达,并使用Spearman相关分析研究食管鳞癌中Pol(ι)与Nm23表达的相关性.向食管癌细胞TE-1和ECA-109转染Pol(ι)表达载体,上调细胞中Pol(ι)的表达,Realtime-PCR检测Po(u)和Nm23 mRNA的表达水平,并通过Transwell侵袭实验分析细胞的侵袭能力.结果:在食管鳞癌临床组织标本中,Pol(ι)表达与淋巴结转移相关(P＜0.01),与Nm23蛋白表达呈负相关(R=-0.481,P＜0.05).上调Pol(ι)的表达增强了TE-1和ECA-109细胞的侵袭能力,差异有统计学意义(P均＜ 0.05),同时抑制了细胞中Nm23 mRNA的表达,差异有统计学意义(P＜ 0.001).结论:Pol(ι)的表达与食管鳞癌的转移密切相关,其可能通过下调Nm23的表达来促进肿瘤转移.

DNA polymerase iota (Polι) can repair several types of DNA damage but has extremely low fidelity. Previous studies have shown an aberrantly elevated Polι expression in human esophageal squamous cell cancer tissues. However, there were few reports describing the role of Polι in esophageal cancer progression. Based on Real-time PCR assay, we found Polι expression was up-regulated in esophageal cancer tissues compared to adjacent normal tissues and overexpression of Polι was correlated to lymph node metastasis. Clonogenic assay and transwell chamber assay showed that overexpression of Polι had higher clongenic capability and invasive tendency in human esophageal squamous cell cancer cells. Expression of cyclin D1, an important cell cycle regulator, was found to be associated with that of Polι in tissue samples and cancer cells as analyzed by real-time PCR, immunohistochemistry, Western blotting and immunofluorescence assay. Flow cytometry analysis further showed that cell cycle distribution was altered in Polι overexpressing cells. These results indicated that expression of Polι correlates significantly with tumor proliferation and invasion. We conclude that Polι is involved in the degree of aggressiveness of human esophageal squamous cell cancer.

Docosahexaenoic acid (DHA), a derivative of ω3- polyunsaturated fatty acids present in fish oil, is well known to have anticancer activity on colon cancer cells, but the molecular and cellular mechanisms remain to be further clarified. In this study, anti-cancer effects of DHA on colon cancer cells were observed in a nude mouse HCT-15 xenograft model. And then, the different genes expression and signal pathways involved in this process were screened and identified using cDNA microarray analysis. Results of genes expression profiles indicated a reprogramming pattern of previously known and unknown genes and transcription factors associated with the action of DHA on colon cancer cells. And several genes related to tumor growth and metastasis including COX2, HIF-1α, VEGF-A, COMP, MMP-1, MMP-9, SCP2, SDC3, which were down-regulated by DHA, were further confirmed in HCT-15 cell line using RT-PCR method. In summary, our data might provide novel information for anti-cancer mechanism of DHA in colon cancer model.

DNA polymerase iota (Polt),as well as Revl,Polκ and Polη,are all Y family DNA polymerases,which are able to replicate damaged DNA via translesion synthesis pathway.However,Pol(t) has the lowest fidelity among all DNA polymerases in both correct and inaccurate DNA templates.Also Pol(t) can bypass certain DNA damages and accumulate mutations.Recent studies show that the aberrant expression of Pol(t) is observed in human uveal melanoma,breast cancer,bladder cancer,lung cancer and esophageal cancer,which may contribute to the tumorigenesis and progression of tumor.The special role of Pol(t) in replicating damaged DNA may contribute to the resistance in oncotherapy.

Exposure to radiation provokes cellular responses, which are likely regulated by gene expression networks. MicroRNAs are small non-coding RNAs, which regulate gene expression by promoting mRNA degradation or inhibiting protein translation. The expression patterns of both mRNA and miRNA during the radiation-induced lung injury (RILI) remain less characterized and the role of miRNAs in the regulation of this process has not been studied. The present study sought to evaluate miRNA and mRNA expression profiles in the rat lung after irradiation.

Objective To investigate the effect of heme oxygenase-1 ( HO-1 ) on the acute radiation-induced skin injury by gene transfer.Methods Thirty-three male SD rats were randomly divided into three groups as PBS-injected group,Ad-EGFP-injeeted group and Ad-HO-1-injected group ( n =11 ).In each group,three rats were used for determining the expression of target gene and the other rats were irradiated on the buttock skin with 40 Gy electron beam generated by a linear accelerator.Immediately after irradiation,rats were administered with a subcutaneous injection of PBS,Ad-EGFP or Ad-HO-1,respectively.Subsequently,the skin reactions were measured twice a week using the semi-quantitative skin injury scale.Results The strong positive expression of HO-1 was observed in subcutaneous dermal tissue after injection of Ad-HO-1.Compared to the PBS-injected group or the Ad-EGFP-injected group,a significant mitigation of skin injury was observed in Ad-HO-1-injected mice 14 d after irradiation (q =0.000-0.030,P ＜ 0.05 ).Conclusions HO-1 could significantly mitigate radiation-induced acute skin injury and Ad-HO-1 could be used to treat radiation-induced skin injury.

OBJECTIVE:Radiation-induced skin injury remains a serious concern for radiation therapy. Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme catabolism, has been reported to have potential antioxidant and anti-apoptotic properties. However, the role of HO-1 in radiation-induced skin damage remains unclear. This study aims to elucidate the effects of HO-1 on radiation-induced skin injury in rats.METHODS:A control adenovirus (Ad-EGFP) and a recombinant adenovirus (Ad-HO1-EGFP) were constructed. Rats were irradiated to the buttock skin with a single dose of 45 Gy followed by a subcutaneous injection of PBS, 5 × 109 genomic copies of Ad-EGFP or Ad-HO1-EGFP (n = 8). After treatment, the skin MDA concentration, SOD activity and apoptosis were measured. The expression of antioxidant and pro-apoptotic genes was determined by RT-PCR and real-time PCR. Skin reactions were measured at regular intervals using the semi-quantitative skin injury score.RESULTS:Subcutaneous injection of Ad-HO1-EGFP infected both epidermal and dermal cells and could spread to the surrounding regions. Radiation exposure upregulated the transcription of the antioxidant enzyme genes, including SOD-1, GPx2 and endogenous HO-1. HO-1 overexpression decreased lipid peroxidation and inhibited the induction of ROS scavenging proteins. Moreover, HO-1 exerted an anti-apoptotic effect by suppressing FAS and FASL expression. Subcutaneous injection of Ad-HO1-EGFP demonstrated significant improvement in radiation-induced skin injury.CONCLUSIONS:The present study provides evidences for the protective role of HO-1 in alleviating radiation-induced skin damage in rats, which is helpful for the development of therapy for radiation-induced skin injury.

AIM: To examine the effect of short hairpin RNA(shRNA)-mediated silencing of the epidermal growth factor receptor (EGFR) gene on the proliferation of human colorectal cancer cells and to explore the potential mechanisms involved. METHODS: Vectors containing shRNA targeting EGFR were constructed. HCT-15 cells were transfected with EGFR-shRNA-1, EGFR-shRNA-2, EGFR-shRNA-3 or shRNA-NC expression vectors, and stably transfected cell lines were screened. The mRNA level of EGFR was assessed by semi-quantitative RT-PCR. Protein expression and cell cycle changes were determined by flow cytometry. Cell proliferative capacity was assessed by colony formation assay. RESULTS: Compared to shRNA-NC, transfection of the three shRNA vectors significantly inhibited EGFR expression, especially shRNA-1 and shRNA-2 vectors (40.2% ± 3.2% and 52.8% ± 11.3%, respectively). The mRNA expression of EGFR in shRNA-1-and shRNA-2-transfected cells also decreased significantly. The colony size and number decreased signifi cantly in cells tranfected with shRNA-1 or shRNA (P < 0.05). The percentage of cells in G0/G1 phase increased (63.69% ± 2.75%, 60.10% ± 2.00%; both P < 0.05) and that of in S phase decreased (28.20% ± 2.42%, 27.19% ± 1.95%; both P < 0.05) in shRNA-1- and shRNA-2-transfected cells. CONCLUSION: Transfection with shRNAs targeting the EGFR gene was capable of suppressing EGFR expression, decreasing cell proliferative capacity and inducing cycle arrest at G0/G1 phase.