转化生长因子-α和myc癌基因蛋白在卵泡发育与黄体形成及退化中的表达

目的：探讨转化生长因子（ＴＧＦ）－α和ｍｙｃ癌基因蛋白（ｍｙｃ蛋白）对人卵巢卵泡发育的局部调控机理。方法：收集３６例月经规则、因不同妇科情况切除的子宫及卵巢标本，采用免疫组织化学方法，研究ＴＧＦ－α和ｍｙｃ蛋白在卵巢组织中的表达。结果：卵母细胞在始基卵泡阶段，ＴＧＦ－α和ｍｙｃ蛋白的表达呈强阳性，随着卵泡的发育与成熟表达逐渐减弱。在颗粒细胞中，ＴＧＦ－α和ｍｙｃ蛋白表达均出现在窦前卵泡阶段，随卵泡的增大与成熟，ＴＧＦ－α表达逐渐增强。闭锁卵泡中ＴＧＦ－α和ｍｙｃ蛋白表达仅限于卵泡膜细胞。在晚期退化的黄体中，ＴＧＦ－α和ｍｙｃ蛋白表达均局限于黄体中央瘢痕周围的黄体膜细胞。结论：ＴＧＦ－α和ｍｙｃ蛋白作为卵巢内局部的调节因子，通过自分泌和旁分泌途径，协同参与人卵母细胞最初的生长、卵泡细胞的增殖分化和黄体细胞凋亡的过程。     

An Embryonic Diapause-like Adaptation with Suppressed Myc Activity Enables Tumor Treatment Persistence

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A MEK/PI3K/HDAC inhibitor combination therapy for KRAS mutant pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive, metastatic disease with limited treatment options. Factors contributing to the metastatic predisposition and therapy resistance in pancreatic cancer are not well understood. Here, we used a mouse model of KRAS-driven pancreatic carcinogenesis to define distinct subtypes of PDAC metastasis: epithelial, mesenchymal and quasi-mesenchymal. We examined pro-survival signals in these cells and the therapeutic response differences between them. Our data indicate that the initiation and maintenance of the transformed state are separable, and that KRAS dependency is not a fundamental constant of KRAS-initiated tumors. Moreover, some cancer cells can shuttle between the KRAS dependent (drug-sensitive) and independent (drug-tolerant) states and thus escape extinction. We further demonstrate that inhibition of KRAS signaling alone via co-targeting the MAPK and PI3K pathways fails to induce extensive tumor cell death and, therefore, has limited efficacy against PDAC. However, the addition of histone deacetylase (HDAC) inhibitors greatly improves outcomes, reduces the self-renewal of cancer cells, and blocks cancer metastasis in vivo. Our results suggest that targeting HDACs in combination with KRAS or its effector pathways provides an effective strategy for the treatment of PDAC.     

γ-Catenin-Dependent Signals Maintain BCR-ABL1+ B Cell Acute Lymphoblastic Leukemia

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Epstein–Barr virus patterns in US Burkitt lymphoma tumors from the SEER residual tissue repository during 1979–2009

Burkitt lymphoma (BL) occurs at all ages, but the patterns of Epstein–Barr virus (EBV) positivity in relation to human immunodeficiency virus (HIV), immunoprofiles and age have not been fully explored. BL tissues from residual tissue repositories, and two academic centers in the United States were examined by expert hematopathologists for morphology, immunohistochemistry, MYC rearrangement, EBV‐encoded RNA (EBER), and diagnosed according to the 2008 WHO lymphoma classification. Analysis was done using frequency tables, Chi‐squared statistics, and Student's t‐test. Of 117 cases examined, 91 were confirmed as BL. The age distribution was 26%, 15%, 19%, and 29% for 0–19, 20–34, 35–59, 60+ years, and missing in 11%. MYC rearrangement was found in 89% and EBER positivity in 29% of 82 cases with results. EBER positivity varied with age (from 13% in age group 0–19 to 55% in age group 20–34, and fell to 25% in age group 60+ years, p = 0.08); with race (56% in Blacks/Hispanics vs 21% in Whites/Asians/Pacific Islanders, p = 0.006); and by HIV status (64% in HIV positive vs 22% in HIV negative cases, p = 0.03). EBER positivity was demonstrated in about one‐third of tumors and it was strongly associated with race and HIV status, and marginally with age‐group.     

MYC and gastric adenocarcinoma carcinogenesis

MYC is an oncogene involved in cell cycle regulation, cell growth arrest, cell adhesion, metabolism, ribosome biogenesis, protein synthesis, and mitochondrial function. It has been described as a key element of several carcinogenesis processes in humans. Many studies have shown an association between MYC deregulation and gastric cancer. MYC deregulation is also seen in gastric preneoplastic lesions and thus it may have a role in early gastric carcinogenesis. Several studies have suggested that amplification is the main mechanism of MYC deregulation in gastric cancer. In the present review, we focus on the deregulation of the MYC oncogene in gastric adenocarcinoma carcinogenesis, including its association with Helicobacterpylori （Hpylon] and clinical applications.     

The matricellular protein CCN3 regulates NOTCH1 signalling in chronic myeloid leukaemia

Deregulated NOTCH1 has been reported in lymphoid leukaemia, although its role in chronic myeloid leukaemia (CML) is not well established. We previously reported BCR‐ABL down‐regulation of a novel haematopoietic regulator, CCN3, in CML; CCN3 is a non‐canonical NOTCH1 ligand. This study characterizes the NOTCH1–CCN3 signalling axis in CML. In K562 cells, BCR‐ABL silencing reduced full‐length NOTCH1 (NOTCH1‐FL) and inhibited the cleavage of NOTCH1 intracellular domain (NOTCH1‐ICD), resulting in decreased expression of the NOTCH1 targets c‐MYC and HES1. K562 cells stably overexpressing CCN3 (K562/CCN3) or treated with recombinant CCN3 (rCCN3) showed a significant reduction in NOTCH1 signalling (> 50% reduction in NOTCH1‐ICD, p < 0.05). Gamma secretase inhibitor (GSI), which blocks NOTCH1 signalling, reduced K562/CCN3 colony formation but increased that of K562/control cells. GSI combined with either rCCN3 or imatinib reduced K562 colony formation with enhanced reduction of NOTCH1 signalling observed with combination treatments. We demonstrate an oncogenic role for NOTCH1 in CML and suggest that BCR‐ABL disruption of NOTCH1–CCN3 signalling contributes to the pathogenesis of CML. © 2013 The Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Low incidence of MYC/BCL2 double‐hit in Burkitt lymphoma

Translocations involving MYC are highly characteristic for Burkitt lymphoma (BL). BCL2 expression has also been found previously in about 10 to 20% of BL cases, and BCL2 translocation is a major mechanism for the deregulation of BCL2 expression in non‐Hodgkin lymphomas. However, we know little about the incidence of MYC/BCL2 double‐hit (DH) in BL. We examined BL cases to determine how frequently they contained BCL2 translocations in combination with MYC translocations using fluorescence in situ hybridization. We also determined the effect of BCL2 expression on clinical outcomes of BL. BCL2 translocations were detected in 3.5% (2/57 cases) of the cases, and BCL2 expression was detected in 33%. Two cases with BCL2 translocation also showed BCL2 expression. The incidence of BCL2 expression was significantly higher in patients 16 years of age and older (46%) than in patients under 16 years of age (6%). Among patients 16 years of age and older, we did not detect significant differences in overall survival with respect to BCL2 expression status. In conclusion, BCL2 translocation is a rare cytogenetic abnormality in BL, and BL probably accounts for only a small fraction of MYC/BCL2 DH lymphomas. BCL2 expression in BL is probably not associated with BCL2 translocations.