Time in hemodialysis modulates the levels of genetic damage in hemodialysis patients

It is assumed that hemodialysis treatment can diminish the levels of genetic damage in circulating lymphocytes by cleaning the blood of uremic toxins that cause oxidative stress. However, the hemodialysis process by itself may also induce genomic damage by producing reactive oxygen species (ROS). We conducted a follow‐up study in a group of 70 hemodialysis patients followed for a mean time of 15 months. We investigated the effect of exposure time in hemodialysis on the levels of genetic damage in peripheral blood lymphocytes using the micronucleus assay. In addition, genetic damage after in vitro irradiation with 0.5 Gy was also analyzed to evaluate changes in radiosensitivity. Our results showed that, at the end of the study, there was a decrease in both the basal levels of genetic damage (9.9 ± 1.0 vs. 7.6 ± 0.7) and radiosensitivity values (38.5 ± 3.0 vs. 27.6 ± 2.4). We conclude that hemodialysis procedures may act as an ameliorating factor reducing the genetic damage present in chronic kidney disease patients. Environ. Mol. Mutagen. 55:363–368, 2014. © 2014 Wiley Periodicals, Inc.     

Insights into the theranostic value of precision medicine on advanced radiotherapy to breast cancer

Breast cancer is the most common cancer in women worldwide. “Breast cancer” encompasses a broad spectrum of diseases (i.e., subtypes) with significant epidemiological, clinical, and biological heterogeneity. Each of these subtypes has a different natural history and prognostic profile. Although tumour staging (TNM classification) still provides valuable information in the overall management of breast cancer, the current reality is that clinicians must consider other biological and molecular factors that directly influence treatment decision-making, including extent of surgery, indication for chemotherapy, hormonal therapy, and even radiotherapy (and treatment volumes). The management of breast cancer has changed radically in the last 15 years due to significant advances in our understanding of these tumours. While these changes have been extremely positive in terms of surgical and systemic management, they have also created significant uncertainties concerning integration of local and locoregional radiotherapy into the therapeutic scheme. In parallel, radiotherapy itself has also experienced major advances. Beyond the evident technological advances, new radiobiological concepts have emerged, and genomic data and other patient-specific factors must now be integrated into individualized treatment approaches. In this context, “precision medicine” seeks to provide an answer to these open questions and uncertainties. Although precision medicine has been much discussed in the last five years or so, the concept remains somewhat ambiguous, and it often appear to be used as a “catch-all” term. The present review aims to clarify the meaning of this term and, more importantly, to critically evaluate the role and impact of precision medicine on breast cancer radiotherapy. Finally, we will discuss the current and future of precision medicine in radiotherapy.     

放射后鼻咽癌细胞株C666-1存活亚克隆高表达miR-181a

目的：：初步分析miR-181a与鼻咽癌细胞系C666-1放射敏感的相关性。方法：首先使用大剂量8 Gy的X射线照射C666-1,挑选三个大的存活亚克隆并命名为 C666-1-R1,C666-1-R2和 C666-1-R3,然后应用MTT等技术分析亚克隆及对照母本C666-1细胞系放射敏感性的差异,最后采用实时荧光定量PCR 法,分析三个存活亚克隆及对照C666-1的miR-181 a表达水平。结果：通过MTT比色法检测细胞增殖：6 Gy照射后,三个亚克隆C666-1-R1,C666-1-R2和C666-1-R3的细胞存活率均高于对照细胞C666-1,尤其C666-1-R2在48、72和96 h的存活率增高均有显著性差异(P<0.05),提示C666-1-R2具有放射抗拒性。另一方面,各亚克隆及对照细胞的 miR-181a 的2-△△Ct值如下：C666-1-R1=0.693,C666-1-R2=0.486,C666-1-R3=0.762,C666-1=1。提示放射后存活的三个亚克隆均高表达 miR-181a,尤其放射抗拒亚克隆C666-1-R2的 miR-181a表达更高。结论：miR-181a与鼻咽癌存活亚克隆的放射抗拒性密切相关。miR-181a可能是评估鼻咽癌放射敏感性的一个新分子,miR-181a 与鼻咽癌放射抗拒的相关性值得深入研究。     

Extreme Growth Failure is a Common Presentation of Ligase IV Deficiency

Ligase IV syndrome is a rare differential diagnosis for Nijmegen breakage syndrome owing to a shared predisposition to lympho‐reticular malignancies, significant microcephaly, and radiation hypersensitivity. Only 16 cases with mutations in LIG4 have been described to date with phenotypes varying from malignancy in developmentally normal individuals, to severe combined immunodeficiency and early mortality. Here, we report the identification of biallelic truncating LIG4 mutations in 11 patients with microcephalic primordial dwarfism presenting with restricted prenatal growth and extreme postnatal global growth failure (average OFC ?10.1 s.d., height ?5.1 s.d.). Subsequently, most patients developed thrombocytopenia and leucopenia later in childhood and many were found to have previously unrecognized immunodeficiency following molecular diagnosis. None have yet developed malignancy, though all patients tested had cellular radiosensitivity. A genotype–phenotype correlation was also noted with position of truncating mutations corresponding to disease severity. This work extends the phenotypic spectrum associated with LIG4 mutations, establishing that extreme growth retardation with microcephaly is a common presentation of bilallelic truncating mutations. Such growth failure is therefore sufficient to consider a diagnosis of LIG4 deficiency and early recognition of such cases is important as bone marrow failure, immunodeficiency, and sometimes malignancy are long term sequelae of this disorder.     

Chk1基因沉默对人卵巢癌细胞 A2780放疗敏感性的影响

目的：探讨Chk1基因沉默对人卵巢癌细胞A2780放疗敏感性的影响。方法构建Chk1基因的短发夹RNA（shRNA）质粒转染人卵巢癌细胞A2780,同时以转染空载体和未转染组作为对照组,运用RT-PCR、蛋白免疫印迹方法观察转染前后Chk1基因表达的差异;四甲基偶氮唑蓝试验绘制细胞生长曲线;克隆形成试验观察细胞的放射敏感性变化。结果与对照组相比,构建shRNA表达载体可抑制人卵巢癌细胞A2780中Chk1 mRNA转录和蛋白的表达;Chk1基因沉默后细胞生长明显慢于对照组;并通过解除G2/M期阻滞,显著提高肿瘤细胞对放射线的敏感性。结论靶向Chk1的shRNA能有效抑制人卵巢癌细胞A2780的Chk1基因表达,促进细胞凋亡,增强肿瘤对放疗的敏感性。     

Low and high linear energy transfer radiation sensitization of HCC cells by metformin

The purpose of this study was to investigate the efficacy of metformin as a radiosensitizer for use in combination therapy for human hepatocellular carcinoma (HCC). Three human HCC cell lines (Huh7, HepG2, Hep3B) and a normal human hepatocyte cell line were treated with metformin alone or with radiation followed by metformin. In vitro tests were evaluated by clonogenic survival assay, FACS analysis, western blotting, immunofluorescence and comet assay. Metformin significantly enhanced radiation efficacy under high and low Linear Energy Transfer (LET) radiation conditions in vitro. In combination with radiation, metformin abrogated G2/M arrest and increased the cell population in the sub-G1 phase and the ROS level, ultimately increasing HCC cellular apoptosis. Metformin inhibits the repair of DNA damage caused by radiation. The radiosensitizing effects of metformin are much higher in neutron (high LET)-irradiated cell lines than in γ (low LET)-irradiated cell lines. Metformin only had a moderate effect in normal hepatocytes. Metformin enhances the radiosensitivity of HCC, suggesting it may have clinical utility in combination cancer treatment with high-LET radiation.     

miR-150-5p靶向SIRT1提高肝癌细胞系HepG2放疗敏感性

目的探究miR-150-5p靶向SIRT1提高肝癌细胞放射敏感性的作用机制。方法用分次放疗放射递增法诱导建立放射抵抗型细胞株(RR-HepG2);RT-qPCR检测HepG2和RR-HepG2在不同放射剂量下miR-150-5p的表达水平;细胞克隆实验检测相同放射剂量下两种细胞的放疗敏感性;流式细胞计量术和Western blot检测过表达miR-150-5p对HepG2凋亡的影响;双荧光素酶报告基因法检测miR-150-5p与SIRT1的关联;细胞克隆实验和Western blot检测过表达SIRT1后,细胞的放疗敏感性和凋亡蛋白的变化。结果与亲代HepG2比较,相同放射剂量下,RRHepG2组miR-150-5p的表达量均显著降低(P<0. 05);放射处理后,与control、agomiR-NC组比较,agomiR-150-5p组的细胞存活分数显著降低,敏感性高(P<0. 05),Bax、caspase-9蛋白表达水平显著升高,Bcl-2蛋白表达水平显著降低,细胞凋亡率显著升高;双荧光素酶报告基因法验证miR-150-5p靶向调控SIRT1。与agomiR-NC组比较,野生型(WT) agomiR-150-5p荧光素酶活性显著降低,SIRT1蛋白水平显著降低(P<0. 05);与anta-agomiR-NC比较,野生型(WT) anta-agomiR-150-5p荧光素酶活性显著升高,SIRT1蛋白水平显著升高(P<0. 05);放射处理后,与agomiR-NC组比较,agomiR-150-5p组的细胞存活分数显著降低,Bax、caspase-9蛋白表达水平显著升高,Bcl-2蛋白表达水平显著降低(P<0. 05);与agomiR-150-5p+vector组比较,agomiR-150-5p+SIRT1组的细胞存活分数显著升高,Bax、caspase-9蛋白表达水平显著降低,Bcl-2蛋白表达水平显著升高(P<0. 05)。结论 miR-150-5p靶向SIRT1,下调其表达,提高肝癌细胞放射敏感性,可为临床肝癌放射治疗增敏提供靶点。     

EGFR及NF-κB与鼻咽癌放射敏感性的相关性研究

目的：通过观察EGFR、NF—κB蛋白表达与鼻咽癌放射敏感性的关系，评价两因子在预测鼻咽癌放射敏感性方面的作用，并为以后靶向基因治疗鼻咽癌、提高放疗效果提供理论依据。方法：采用免疫组织化学SP法检测41例鼻咽癌组织中EGFR及NF-κB的表达情况，并通过随访及临床观察，判断每例患者放疗效果，从而将所有患者分为完全缓解组、部分缓解／稳定组和进展组，评定两因子表达水平与放射敏感性的关系。结果：EGFR、NF-κB在鼻咽癌中均有不同程度表达，两者在鼻咽癌组织的不同放射敏感性中表达各具有差异性（P〈0．05）。完全缓解组与部分缓解／稳定组的EGFR、NF-κB表达均低于进展组（P〈0．05），而完全缓解组与部分缓解／稳定组比较差异无统计学意义（P〉0．05）。两因子表达与鼻咽癌放射敏感性呈负相关。结论：EGFR、NF-κB可能成为预测鼻咽癌放射敏感性的2个重要指标，为鼻咽癌患者的靶向基因治疗提供理论依据。