Getting ‘Smad' about obesity and diabetes

Recent findings on the role of transforming growth factor (TGF)-β/Smad3 signaling in the pathogenesis of obesity and type 2 diabetes have underscored its importance in metabolism and adiposity. Indeed, elevated TGF-β has been previously reported in human adipose tissue during morbid obesity and diabetic neuropathy. In this review, we discuss the pleiotropic effects of TGF-β/Smad3 signaling on metabolism and energy homeostasis, all of which has an important part in the etiology and progression of obesity-linked diabetes; these include adipocyte differentiation, white to brown fat phenotypic transition, glucose and lipid metabolism, pancreatic function, insulin signaling, adipocytokine secretion, inflammation and reactive oxygen species production. We summarize the recent in vivo findings on the role of TGF-β/Smad3 signaling in metabolism based on the studies using Smad3^−/− mice. Based on the presence of a dual regulatory effect of Smad3 on peroxisome proliferator-activated receptor (PPAR)β/δ and PPARγ2 promoters, we propose a unifying mechanism by which this signaling pathway contributes to obesity and its associated diabetes. We also discuss how the inhibition of this signaling pathway has been implicated in the amelioration of many facets of metabolic syndromes, thereby offering novel therapeutic avenues for these metabolic conditions.     

绍兴地区肺炎链球菌的血清型和耐药性

目的:调查绍兴地区流行肺炎链球菌的血清型和耐药性,对不同来源的菌株进行比较,计算PCV7的覆盖率,为临床用药提供指导。方法:收集105株不同样本来源的肺炎链球菌,使用Pneumotest-latex鉴定血清型,统计耐药性,并研究两者之间关系。结果:105株肺炎链球菌,青霉素不敏感仅1株咽拭子分离菌,红霉素、克林霉素耐药率为99.3%,未检到万古霉素、左氧氟沙星耐药株,复方SMZ、四环素、利福平、氯霉素的耐药率分别为77.9%、86.2%、5.1%、10.6%。主要检出的血清组/型为19和23,占所有菌株的47.6%(49/103),PCV疫苗覆盖率为62.1%。结论:不同样本来源的肺炎链球菌的流行血清型和耐药性差异有统计学意义,眼部分离肺炎链球菌较其他部位分离株耐药程度低,PCV7覆盖率低,需长期监测。     

Satraplatin: an orally available platinum analog for the treatment of cancer

Satraplatin is a novel, orally bioavailable, platinum anticancer drug. Platinum analogs form the mainstay of treatment for a number of cancers, including lung, ovarian, colorectal and head and neck cancer. A disadvantage of the currently marketed platinum analogs is that they must all be administered via intravenous infusion. In addition, their utility is often limited by toxicity, particularly neurotoxicity, ototoxicity and renal toxicity. Satraplatin has preclinical antitumor activity comparable with that of cisplatin and, clinically, has a more manageable side-effect profile. Satraplatin is active in lung, ovarian and prostate cancer, and appears to have good efficacy in combination with radiation for lung and head and neck cancer. Preclinical data suggest it may also be effective for the treatment of certain cisplatin-refractory tumors. A large, randomized Phase III trial is currently evaluating satraplatin in combination with prednisone for the treatment of patients with hormone-refractory prostate cancer whose disease has progressed following prior systemic therapy. Positive results from this trial would support regulatory approval for satraplatin for this indication. The availability of an active oral platinum agent, such as satraplatin, with few of the serious toxicities associated with traditional intravenous platinum compounds makes satraplatin an alternative to other platinum agents and a new treatment option in the oncologist’s armamentarium.     

Role of tyrosine kinase inhibitors in the management of high-grade gliomas

Recent years have witnessed an explosion of promising therapies for cancer patients. New insights into the biology of malignancies have led to the development of targeted agents with the potential to improve survival and quality of life. One of the most important classes of these compounds are tyrosine kinase inhibitors. These agents are beginning to offer a clinically relevant benefit to patients with tumors that until recently have been refractory to medical therapies. High-grade gliomas represent one class of medically refractory solid tumors. This article summarizes the state of the art of tyrosine kinase inhibitors in the management of patients with high-grade gliomas.     

Genetic disruption of USP9X sensitizes colorectal cancer cells to 5-fluorouracil

The X-linked deubiquitinase USP9X affects the stability and activity of numerous regulatory proteins that influence cell survival. Recent studies suggest that decreased USP9X expression can confer a selective advantage onto developing cancer cells and thereby promotes disease progression. To examine the effect of USP9X on the cellular responses to anticancer therapies, we derived cancer cell lines in which the USP9X locus was disrupted by homologous recombination. The resulting USP9X-deficient cancer cells exhibited increased activation of apoptotic pathways and markedly decreased clonogenic survival in response to 5-fluorouracil, a chemotherapeutic drug that is widely used for treatment of gastrointestinal malignancies. These unexpected results suggest that cancers with low USP9X expression might be specifically sensitized to some conventional therapeutic agents.     

Strategies to Resist Drug Offers Among Urban American Indian Youth of the Southwest: An Enumeration,Classification, and Analysis by Substance and Offeror

This study explores the drug resistance strategies of urban American Indian adolescents when they encounter people offering them alcohol, cigarettes, and marijuana. Data were collected in 2005 from 11 female and 9 male adolescents who self-identified as American Indian and attended two urban middle schools in the southwestern United States. In two focus groups—one at each school site—the youth described their reactions to 25 hypothetical substance offer scenarios drawn from real-life narratives of similar youth. Qualitative analysis of their 552 responses to the scenarios generated 14 categories. Half of the responses were strategies reported most often by nonnative youth (refuse, explain, leave, and avoid). Using ecodevelopmental theory, the responses were analyzed for indications of culturally specific ways of resisting substance offers, such as variation by specific substance and relationship to the person offering. Study limitations are noted along with suggestive implications for future research on culturally appropriate prevention approaches for urban American Indian youth.     

Contemporary management of muscle-invasive bladder cancer

The current standard treatment for muscle-invasive nonmetastatic bladder cancer is neoadjuvant platinum-based chemotherapy followed by radical cystectomy. However, neoadjuvant chemotherapy is not widely accepted even with level 1 evidence. Adjuvant chemotherapy should be discussed if patients have not received neoadjuvant chemotherapy before surgery and have high-risk pathologic features. Although not considered standard of care, bladder-sparing therapy can be considered for highly selected patients and for those medically unfit for surgery. Even though there are no level 1 data, the treatment outcomes for highly select patients given bladder-sparing therapy appear promising, with many patients retaining a functional bladder. Personalized chemotherapy is currently being actively pursued to target the underlying molecular changes and tailor to individual needs.     

123株阴沟肠杆菌的临床分布和耐药性分析

目的 了解医院2010年1月-2011年6月阴沟肠杆菌的临床分布及耐药性分析,为临床合理用药提供依据.方法 从近年来感染标本中分离出阴沟肠杆菌,采用法国生物梅里埃公司VITEK-2 Compact全自动细菌分析仪对所分离的菌株进行鉴定和药敏试验,采用WHONET5.4软件进行统计分析.结果 分离的123株阴沟肠杆菌主要来自于肝胆外科、ICU等科室,标本主要来源于痰液、胆汁及尿液中；阴沟肠杆菌对亚胺培南、美罗培南、厄他培南、阿米卡星等有较好的抗菌活性,敏感率依次为99.19％、99.19％、94.31％、94.31％;而对头孢西丁、头孢唑林、氨苄西林/舒巴坦、头孢替坦、氨苄西林的敏感性较差,敏感率依次为1.63％、1.63％、4.88％、4.88％和4.07％.结论 临床分离的阴沟肠杆菌耐药现象比较严重,应加强耐药性监测,以指导临床合理用药,控制医院感染.     

The small GTPase ADP-Ribosylation Factor 1 mediates the sensitivity of triple negative breast cancer cells to EGFR tyrosine kinase inhibitors

The clinical use of EGFR-targeted therapy, in triple negative breast cancer patients, has been limited by the development of resistance to these drugs. Although activated signaling molecules contribute to this process, the molecular mechanisms remain relatively unknown. We have previously reported that the small GTPase ADP-Ribosylation Factor 1 (ARF1) is highly expressed in invasive breast cancer cells and acts as a molecular switch to activate EGF-mediated responses. In this study, we aimed at defining whether the high expression of ARF1 limits sensitivity of these tumor cells to EGFR inhibitors, such as gefitinib. Here, we show that the knock down of ARF1 expression or activity decreased the dose and latency time required by tyrosine kinase inhibitors to induce cell death. This may be explained by the observation that the depletion of ARF1 suppressed gefitinib-mediated activation of key mediators of survival such as ERK1/2, AKT and Src, while enhancing cascades leading to apoptosis such as the p38MAPK and JNK pathways, modifying the Bax/Bcl2 ratio and cytochrome c release. In addition, inhibiting ARF1 expression and activation also results in an increase in gefitinib-mediated EGFR internalization and degradation further limiting the ability of this receptor to promote its effects. Interestingly, we observed that gefitinib treatment resulted in the enhanced activation of ARF1 by promoting its recruitment to the receptor AXL, an important mediator of EGFR inhibition suggesting that ARF1 may promote its pro-survival effects by coupling to alternative mitogenic receptors in conditions where the EGFR is inhibited. Together our results uncover a new role for ARF1 in mediating the sensitivity to EGFR inhibition and thus suggest that limiting the activation of this GTPase could improve the therapeutic efficacy of EGFR inhibitors.     

Akt inhibition improves irinotecan treatment and prevents cell emergence by switching the senescence response to apoptosis

Activated in response to chemotherapy, senescence is a tumor suppressive mechanism that induces a permanent loss of proliferation. However, in response to treatment, it is not really known how cells can escape senescence and how irreversible or incomplete this pathway is. We have recently described that cells that escape senescence are more transformed than non-treated parental cells, they resist anoikis and rely on Mcl-1. In this study, we further characterize this emergence in response to irinotecan, a first line treatment used in colorectal cancer. Our results indicate that Akt was activated as a feedback pathway during the early step of senescence. The inhibition of the kinase prevented cell emergence and improved treatment efficacy, both in vitro and in vivo. This improvement was correlated with senescence inhibition, p21waf1 downregulation and a concomitant activation of apoptosis due to Noxa upregulation and Mcl-1 inactivation. The inactivation of Noxa prevented apoptosis and increased the number of emergent cells. Using either RNA interference or p21waf1-deficient cells, we further confirmed that an intact p53-p21-senescence pathway favored cell emergence and that its downregulation improved treatment efficacy through apoptosis induction. Therefore, although senescence is an efficient suppressive mechanism, it also generates more aggressive cells as a consequence of apoptosis inhibition. We therefore propose that senescence-inducing therapies should be used sequentially with drugs favoring cell death such as Akt inhibitors. This should reduce cell emergence and tumor relapse through a combined induction of senescence and apoptosis.