ShcC proteins: Brain aging and beyond

To date, most studies of Shc family of signaling adaptor proteins have been focused on the near-ubiquitously expressed ShcA, indicating its relevance to age-related diseases and longevity. Although the role of the neuronal ShcC protein is much less investigated, accumulated evidence suggests its importance for neuroprotection against such aging-associated conditions as brain ischemia and oxidative stress. Here, we summarize more than decade of studies on the ShcC expression and function in normal brain, age-related brain pathologies and immune disorders with a focus on the interactions of ShcC with signaling proteins/pathways, and the possible implications of these interactions for changes associated with aging.     

益气化瘀解毒法对慢性萎缩性胃炎伴异型增生大鼠EGFR/MAPK信号通路的影响

目的观察益气化瘀解毒法对慢性萎缩性胃炎(CAG)伴异型增生(Dys)模型大鼠EGFR/MAPK信号通路的影响。方法 60只SPF级健康雄性Wistar大鼠随机分为空白组10只,造模组50只。空白组给予SPF级动物标准饮食喂养,持续至实验结束。造模组采用以120 mg/L的N-甲基-N'-硝基-N-亚硝基胍(MNNG)溶液灌胃,每只5 m L/kg,1次/d为主,配合自由饮用0.1%氨水溶液及进食含0.03%雷尼替丁的颗粒状饲料,3种因素联合建立CAG伴Dys大鼠模型。28周末造模成功后将造模组剩余的30只大鼠随机分为模型组、维酶素组、益气化瘀解毒法组(中药组),每组各10只,均给予SPF级动物标准饮食喂养,并且每天灌胃1次,维酶素组予维酶素悬浊液2 m L/kg(即维酶素0.3 g/kg),中药组予益气化瘀解毒中药3 m L/kg(含生药9 g/kg),模型组予生理盐水3m L/kg。12周后即实验第40周末处死全部大鼠。选用Western blot法对各组大鼠胃窦部黏膜组织中EGFR、ERK1/2、p-ERK1/2蛋白表达进行检测。结果模型组EGFR蛋白表达最高,其次是维酶素组、中药组、空白组;其中,模型组与空白组和中药组比较均有显著性差异(均P0.01),中药组与维酶素组比较有显著性差异(P0.05)、与空白组比较无显著性差异(P0.05)。模型组ERK1/2蛋白表达最高,其次是维酶素组、中药组、空白组;其中,模型组、维酶素组与空白组和中药组比较均有显著性差异(均P0.01),中药组与空白组比较也有显著性差异(P0.01)。模型组p-ERK1/2蛋白表达最高,其次是维酶素组、中药组、空白组;其中,模型组与空白组和中药组比较均有显著性差异(均P0.01),中药组与维酶素组有显著性差异(P0.01)、与空白组比较无显著性差异。结论益气化瘀解毒法可显著抑制EGFR的高表达及EGFR/MAPK细胞信号转导通路的异常激活,这可能是其治疗CAG伴Dys、逆转胃癌前病变(PLGC)、防治胃癌的有效作用机制之一。     

Liquid biopsy is a valuable tool in the diagnosis and management of lung cancer

Liquid biopsy refers to the use of various body fluids to test for circulating biological elements derived from the tumor. Liquid biopsy has taken on an increasingly important role in lung cancer diagnosis, molecular characterization, surveillance, monitoring, and determining mechanisms of resistance. These assays can utilize various sources of cell-free DNA (cfDNA) including blood, pleural fluid, urine, and others to detect tumor associated alterations. With the increasing power of next-generation sequencing technologies and the development of assays such as digital droplet PCR, rare tumor alleles can be detected in cfDNA to determine key characteristics of the tumor. Current assays, while effective, are still challenged by limited sensitivity and capacity to single genes or small panels of genes, though this is rapidly expanding. Nevertheless, testing of cfDNA has been shown to be valuable in detecting resistance to targeted inhibitors, particularly for detection of T790M in EGFR and monitoring response to therapy. With the continued development of more powerful and sensitive assays, these techniques will empower clinicians to better characterize early stage disease and can be used in the screening of high-risk patients, which may eliminate the requirement for tissue diagnosis in some settings. That said, since the majority of these alterations are not specific to lung cancer, there will continue to be a need for tissue in at least the initial diagnosis. Used in conjugation with tissue sampling, these assays will assist the treating clinician and the pathologist to better characterize individual tumors, even in the setting of limited tissue.     

Subchronic inhalation of coal dust particulate matter 10 induces bronchoalveolar hyperplasia and decreases MUC5AC expression in male Wistar rats

Coal dust is a pollutant found in coal mines that are capable of inducing oxidative stress and inflammation, but the effects on lung metaplasia as an early step of carcinogenesis remain unknown. The purpose of the present study was to evaluate the effects of PM₁₀ coal dust on lung histology, MUC5AC expression, epidermal growth factor (EGF) expression, and epidermal growth factor receptor (EGFR) expression. An experimental study was done on male Wistar rats, which were divided into the following groups: control groups exposed to coal dust for 14 days (at doses of 6.25 mg/m³, 12.5 mg/m³, and 25 mg/m³), and the groups exposed to coal dust for 28 days (at doses of 6.25 mg/m³, 12.5 mg/m³, and 25 mg/m³). EGF expressions in rat lungs were measured by ELISA. EGFR and MUC5AC were measured by a confocal laser scanning microscope. The bronchoalveolar epithelial image of the group exposed to coal dust for 14 and 28 days showed a epithelial rearrangement, hyperplastic (metaplastic) goblet cells, and scattered massive inflammatory cells. The pulmonary parenchymal image of the group of exposed to coal dust for 14 and 28 days showed scattered inflammatory cells filling up the pulmonary alveolar networks, leading to an appearance of thickened parenchymal alveoli until emphysema-like structure. There was no significant difference in MUC5AC, EGF, and EGFR expressions for 14-d exposure (p > 0.05). There was no significant difference in EGF and EGFR expressions for 28-d exposure (p > 0.05), but there was a significant difference in MUC5AC expression (p < 0.05). We concluded that subchronic inhalation of coal dust particulate matter 10 induces bronchoalveolar reactive hyperplasia and rearrangement of epithelial cells which accompanied by decrease expression MUC5AC in male rats.     

High frequency of BRAF V600E mutations in ameloblastoma

Ameloblastoma is a benign but locally infiltrative odontogenic neoplasm. Although ameloblastomas rarely metastasise, recurrences together with radical surgery often result in facial deformity and significant morbidity. Development of non‐invasive therapies has been precluded by a lack of understanding of the molecular background of ameloblastoma pathogenesis. When addressing the role of ERBB receptors as potential new targets for ameloblastoma, we discovered significant EGFR over‐expression in clinical samples using real‐time RT–PCR, but observed variable sensitivity of novel primary ameloblastoma cells to EGFR‐targeted drugs in vitro. In the quest for mutations downstream of EGFR that could explain this apparent discrepancy, Sanger sequencing revealed an oncogenic BRAF V600E mutation in the cell line resistant to EGFR inhibition. Further analysis of the clinical samples by Sanger sequencing and BRAF V600E‐specific immunohistochemistry demonstrated a high frequency of BRAF V600E mutations (15 of 24 samples, 63%). These data provide novel insight into the poorly understood molecular pathogenesis of ameloblastoma and offer a rationale to test drugs targeting EGFR or mutant BRAF as novel therapies for ameloblastoma. Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk     

Pivotal role of MUC1 glycosylation by cigarette smoke in modulating disruption of airway adherens junctions in vitro

Cigarette smoke increases the risk of lung cancer by 20‐fold and accounts for 87% of lung cancer deaths. In the normal airway, heavily O‐glycosylated mucin‐1 (MUC1) and adherens junctions (AJs) establish a structural barrier that protects the airway from infectious, inflammatory and noxious stimuli. Smoke disrupts cell–cell adhesion via its damaging effects on the AJ protein epithelial cadherin (E‐cad). Loss of E‐cad is a major hallmark of epithelial–mesenchymal transition (EMT) and has been reported in lung cancer, where it is associated with invasion, metastasis and poor prognosis. Using organotypic cultures of primary human bronchial epithelial (HBE) cells treated with smoke‐concentrated medium (Smk), we have demonstrated that E‐cad loss is regulated through the aberrant interaction of its AJ binding partner, p120‐catenin (p120ctn), and the C‐terminus of MUC1 (MUC1‐C). Here, we reported that even before MUC1‐C became bound to p120ctn, smoke promoted the generation of a novel 400 kDa glycoform of MUC1's N‐terminus (MUC1‐N) differing from the 230 kDa and 150 kDa glycoforms in untreated control cells. The subsequent smoke‐induced, time‐dependent shedding of glycosylated MUC1‐N exposed MUC1‐C as a putative receptor for interactions with EGFR, Src and p120ctn. Smoke‐induced MUC1‐C glycosylation modulated MUC1‐C tyrosine phosphorylation (TyrP) that was essential for MUC1‐C/p120ctn interaction through dose‐dependent bridging of Src/MUC1‐C/galectin‐3/EGFR signalosomes. Chemical deglycosylation of MUC1 using a mixture of N‐glycosylation inhibitor tunicamycin and O‐glycosylation inhibitor benzyl‐α‐GalNAc disrupted the Src/MUC1‐C/galectin‐3/EGFR complexes and thereby abolished smoke‐induced MUC1‐C‐TyrP and MUC1‐C/p120ctn interaction. Similarly, inhibition of smoke‐induced MUC1‐N glycosylation using adenoviral shRNA directed against N‐acetyl‐galactosaminyl transferase‐6 (GALNT6, an enzyme that controls the initiating step of O‐glycosylation) successfully suppressed MUC1‐C/p120ctn interaction, prevented E‐cad degradation and maintained cellular polarity in response to smoke. Thus, GALNT6 shRNA represents a potential therapeutic modality to prevent the initiation of events associated with EMT in the smoker's airway. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

QSAR of clinically important EGFR mutant L858R/T790M pyridinylimidazole inhibitors

EGFR is a well‐established therapeutic target of clinical relevance in cancer. However, acquisition of secondary mutation (T790M) makes first‐generation inhibitors ineffective. Therefore, to circumvent the problem of resistance, new T790M/L858R (TMLR) double mutant inhibitors are required. In this study, fragment‐based QSAR models (GQSAR) were generated for pyridinylimidazole derivatives having biological activity against TMLR mutants. The GQSAR model developed using partial least squares regression via stepwise forward–backward variable selection technique showed best results as judged using statistical parameters (r², q², and pred_r²). Additionally, applicability domain of the model was verified using Williams plot, which indicated that the predicted data are reliable. The GQSAR provided site‐specific clues wherein modifications related to decreasing lipophilic character and rotatable bonds and increasing SaaCHE‐index are required for improving inhibitory activity. Overall, the study indicated that the presence of acrylamide at R5 is essential for covalent bond formation with Cys797 and occurrence of aromatic residue at R2 is required for occupying hydrophobic region next to Met790 gatekeeper residue. Based on this information, new derivatives were designed that show better inhibitory activity than the experimentally reported most active molecules. Thus, the model developed can be used to design new pyridinylimidazole derivatives with improved TMLR bioactivity.     

非小细胞肺癌患者EGFR、ALK基因突变及临床病理特征与预后的相关性研究

目的探讨非小细胞肺癌(NSCLC)患者EGFR、ALK基因突变状态及病理特征,分析二者与患者预后情况相关性。方法收集2015年1月至2018年1月苏州大学附属第一医院病理确诊的NSCLC病例262例,记录患者临床病理特征及转归,采用突变增阻滞系统(ARMS)-Taqman探针法及RT-PCR检测患者肿瘤样本的EGFR和ALK基因外显子突变情况,采用Kaplan-Meier法和Cox风险回归考察不同基因突变情况的预后、临床病理特征与临床结局的相关性。结果262例NSCLC患者中,168例为野生型,ALK突变12例,突变率4.6%;EGFR突变82例,突变率31.30%,其中18号外显子突变2例,19号外显子突变37例,20号外显子突变9例,21号外显子突变31例;各组间年龄、病理类型比较差异有统计学意义,P<0.05;Wild type组中位OS时间11.6月,ALK组中位OS时间15.0月,EGFR组中位OS时间36.8月,EGFR组OS明显优于ALK组OS时间及Wild type组OS时间,P<0.05;EGFR19号外显子突变组、21号外显子突变组OS生存时间显著高于18号外显子突变组和20号外显子突变组,P<0.05;EGFR阴性(RR=15.751,95%CI:9.252~26.816)、鳞癌(RR=18.344,95%CI:6.187~54.388)为OS的危险因素。结论EGFR突变状态、病理类型对非小细胞肺癌预后具有良好的预测价值,鳞癌和EGFR阴性患者生存期短。EGFR基因少见突变(18号外显子、20号外显子)患者的中位OS时间更短。