The role of epigenetic therapies in colorectal cancer

Although developments in the diagnosis and therapy of colorectal cancer (CRC) have been made in the last decade, much work remains to be done as it remains the second leading cause of cancer death. It is now well established that epigenetic events, together with genetic alterations, are key events in initiation and progression of CRC. Epigenetics refers to heritable alterations in gene expression that do not involve changes in the DNA sequence. These alterations include DNA methylation, histone alterations, chromatin remodelers, and noncoding RNAs. In CRC, aberrations in epigenome may also involve in the development of drug resistance to conventional drugs such as 5-fluorouracil, oxaliplatin, and irinotecan. Thus, it has been suggested that combined therapies with epigenetic agents may reverse drug resistance. In this regard, DNA methyltransferase inhibitors and histone deacetylase inhibitors have been extensively investigated in CRC. The aim of this review is to provide a brief overview of the preclinical data that represent a proof of principle for the employment of epigenetic agents in CRC with a focus on the advantages of combinatorial therapy over single-drug treatment. We will also critically discuss the results and limitations of initial clinical experiences of epigenetic-based therapy in CRC and summarize ongoing clinical trials. Nevertheless, since recent translational research suggest that epigenetic modulators play a key role in augmenting immunogenicity of the tumor microenvironment and in restoring immune recognition, we will also highlight the recent developments of combinations strategies of immunotherapies and epigenetic therapies in CRC, summarizing preclinical, and clinical data to signify this evolving and promising field for CRC treatment.     

右美托咪定抑制大鼠创伤性脑损伤后神经细胞凋亡

  目的  探讨右美托咪定（DEX）对创伤性脑损伤（TBI）的神经保护作用是否与抑制神经细胞凋亡有关，是否涉及SIRT1信号通路。  方法  将SD大鼠随机分为Sham组、TBI + NS组、TBI + DEX组和TBI + DEX + EX527组。采用干/湿重法评估脑创伤后脑组织含水量；神经功能缺损评分检查神经功能受损情况；Western blot法检测大鼠皮质Bcl-2和Bax蛋白的表达水平。  结果  实验结果显示DEX干预后可减少脑创伤后促凋亡的调控蛋白Bax表达，差异有统计学意义（P < 0.05），增加抑制凋亡的调控蛋白Bcl-2表达，差异有统计学意义（P < 0.05），减轻脑水肿，差异有统计学意义（P < 0.05）和改善神经功能，差异有统计学意义（P < 0.05），上述观测指标的变化可被SIRT1抑制剂EX527逆转。  结论  提示DEX通过抑制神经细胞凋亡而减轻脑创伤后的继发性损害，该神经保护作用与SIRT1信号通路之间存在一定相关性。     

A Phase II Study of CLAG Regimen Combined With Imatinib Mesylate for Relapsed or Refractory Acute Myeloid Leukemia

IntroductionNo standard salvage chemotherapy regimen is available for relapsed or refractory (RR) acute myeloid leukemia (AML). Preclinical data have suggested synergy in vitro between cytarabine and imatinib mesylate (IM) on AML cell growth inhibition. After demonstrating the safety and feasibility in a phase I study, we conducted a phase II clinical study of CLAG (cladribine, cytarabine, granulocyte colony-stimulating factor) regimen combined with IM for patients with RR-AML.Patients and MethodsWe performed a single-institution 2-stage phase II study. The primary endpoint was the remission rate measured using the standard AML response criteria. The secondary endpoints included overall survival (OS) and progression-free survival (PFS).ResultsFrom August 2009 to April 2011, 38 patients were treated at the Moffitt Cancer Center. Their median age was 62 years (range, 26-79 years). Of the 38 patients, 7 (18%) had refractory AML, 19 (50%) had early relapse, and 12 (32%) had late relapse. At the original diagnosis, only 2 patients had favorable risk factors, 18 had intermediate risk, and 16 had poor risk; for 2 patients, the karyotype was missing. The overall response rate for all 38 evaluable patients was 37%. The median OS was 11.1 months (95% CI, 4.8-13.4 months), the median PFS was 4.9 months (95% CI, 1.6-11.7 months). Among the responders, 8 of 14 patients subsequently underwent allogeneic hematopoietic cell transplantation.ConclusionCLAG plus IM was well tolerated, with encouraging signs of activity in patients with poor-risk AML.     

肝细胞移植的研究现状与进展

肝细胞移植是一种通过对获得的正常肝组织进行体外分离纯化,并将分离纯化的肝细胞植入患者体内暂时性地对遗传性代谢性肝病和急性肝衰竭等患者提供代谢性支持的新方法。经过多年的发展,肝细胞移植技术已经取得很大的进展,目前在临床应用已有成功案例,但距离临床广泛应用仍需要进一步的研究。     

Silencing of MicroRNA-21 confers the sensitivity to tamoxifen and fulvestrant by enhancing autophagic cell death through inhibition of the PI3K-AKT-mTOR pathway in breast cancer cells

Tamoxifen (TAM) and fulvestrant (FUL) represent the major adjuvant therapy to estrogen receptor-alpha positive (ER⁺) breast cancer patients. However, endocrine resistance to TAM and FUL is a great impediment for successful treatment. We hypothesized that miR-21 might alter the sensitivity of breast cancer cells to TAM or FUL by regulating cell autophagy. Using the ER⁺ breast cancer cells, we knockdown miR-21.by transfection with miR-21 inhibitor, then the cells were exposed to TAM or FUL and the percentages of apoptosis and autophagy were determined. Knockdown of miR-21 significantly increased the TAM or FUL-induced apoptosis in ER⁺ breast cancer cells. Further, silencing of miR-21 in MCF-7 cells enhanced cell autophagy at both basal and TAM or FUL-induced level. The increase of autophagy in miR-21-knockdown MCF-7 cells was also indicated by increase of beclin-1, LC3-II and increased GFP-LC3 dots. Importantly, knockdown of miR-21 contributed to autophagic cell death, which is responsible for part of TAM induced cell death in miR-21 inhibitor-transfected cells. Further analysis suggested that miR-21 inhibitor enhance autophagic cell death through inhibition of PI3K-AKT-mTOR pathway. MiR-21 coordinated the function of autophagy and apoptosis by targeting Phosphatase and tensin homolog (PTEN) through inhibition of PI3K-AKT-mTOR pathway. In conclusion, silencing of miR-21 increased the sensitivity of ER⁺ breast cancer cells to TAM or FUL by increasing autophagic cell death. Targeting autophagy-related miRNAs is a potential strategy for overcoming endocrine resistance to TAM and FUL.     

应用抗甲状腺药物致粒细胞缺乏患者感染的临床研究

目的分析使用抗甲状腺药物(ATD)引起粒细胞缺乏及引发感染患者的临床特点和感染部位、病原菌分布及其耐药性。方法回顾性分析72例使用ATD引起粒细胞缺乏及引发感染患者的临床资料,采用SPSS11.0软件进行统计分析。结果 72例患者感染部位以呼吸道为主,占55.3%,其次为泌尿系、胃肠道,分别占21.1%和10.5%;共分离出病原菌52株,其中革兰阳性菌20株占38.5%;革兰阴性菌26株占50.0%;真菌6株占11.5%;革兰阳性菌对万古霉素和替考拉宁敏感性最高,分别为90.0%和100.0%,对其他抗菌药物均存在不同程度的耐药性;革兰阴性菌对美罗培南和亚胺培南敏感性最高,均为92.3%,对第三代头孢类药物、阿米卡星等存在不同程度的耐药性。结论使用ATD容易引起患者粒细胞缺乏,继而诱发各种感染,且感染部位以呼吸道最为常见,引起感染的病菌中革兰阴性菌与革兰阳性菌相当,真菌感染相对较少。