Malignant astrocytoma-derived region of common amplification in chromosomal band 17p12 is frequently amplified in high-grade osteosarcomas

Recently, we reported a new amplification event that involves marker D17S67 in 17p12 in three malignant astrocytomas of patients with a very short survival. The amplified region may contain an oncogene implicated in astrocytoma tumorigenesis. To determine the extent of the amplified regions, we constructed a yeast artificial chromosome contig spanning the D17S67 region and tested the amplification status of markers that map to the contig. We determined a commonly amplified region between markers D17S1311 and D17S1875 with a maximal length of 1,630 kb. By using marker 745R, from within the commonly amplified region, we screened 60 high-grade astrocytomas but could not detect additional tumors with the amplification event. This suggests that the incidence of the amplification event in high-grade astrocytoma is low (5%). It has recently been shown by comparative genomic hybridization that amplification of 17p11-p12 is a frequent event in high-grade osteosarcomas, occurring in 20–30% of cases. Since the commonly amplified region is within 17p12, we tested 745R in 20 osteosarcomas, including 6 lung metastases, and detected amplification in 9 cases (45%). Marker 745R was found to be amplified in 4 of the 6 lung metastases (66%). From this frequent involvement and the association with clinically aggressive astrocytomas we conclude that for both tumor types presence of the amplification event seems to correlate with aggressive clinical behaviour. Genes Chromosom. Cancer 18:279–285, 1997. © 1997 Wiley-Liss, Inc.     

Prostate epithelial-specific expression of activated PI3K drives stromal collagen production and accumulation

We genetically engineered expression of an activated form of P110 alpha, the catalytic subunit of PI3K, in mouse prostate epithelium to create a mouse model of direct PI3K activation (Pbsn-cre4Prb;PI3K^GOF/+). We hypothesized that direct activation would cause rapid neoplasia and cancer progression. Pbsn-cre4Prb;PI3K^GOF/+ mice developed widespread prostate intraepithelial hyperplasia, but stromal invasion was limited and overall progression was slower than anticipated. However, the model produced profound and progressive stromal remodeling prior to explicit epithelial neoplasia. Increased stromal cellularity and inflammatory infiltrate were evident as early as 4 months of age and progressively increased through 12 months of age, the terminal endpoint of this study. Prostatic collagen density and phosphorylated SMAD2-positive prostatic stromal cells were expansive and accumulated with age, consistent with pro-fibrotic TGF-β pathway activation. Few reported mouse models accumulate prostate-specific collagen to the degree observed in Pbsn-cre4Prb;PI3K^GOF/+. Our results indicate a signaling process beginning with prostatic epithelial PI3K and TGF-β signaling that drives prostatic stromal hypertrophy and collagen accumulation. These mice afford a unique opportunity to explore molecular mechanisms of prostatic collagen accumulation that is relevant to cancer progression, metastasis, inflammation and urinary dysfunction. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

A transgenic mouse with vascular endothelial over-expression of the non-muscle myosin light chain kinase-2 isoform is susceptible to inflammatory lung injury: role of sexual dimorphism and age

We have generated genetically engineered mice that are uniquely susceptible to lipopolysaccharide (LPS)-induced and mechanical ventilation-induced lung injury in a sex-specific and age-specific manner. These mice express a nonmuscle isoform of the myosin light chain kinase gene (nmMLCK2) targeted to the endothelium. Homozygous mice have significantly reduced fecundity and litter survival until weaning, and they are initially growth delayed but eventually exceed the size of wild-type littermates. Mice at all ages show increased protein transport across the lung barrier; however, the phenotype is most discernible in 8-12-week-old male mice. When subjected to a clinically relevant LPS-induced lung injury model, 8-12-week-old young females and 30-36-week-old males seem to be the most significantly injured group. In contrast, 30-36-week-old males remain the most significantly injured group when mechanically ventilated at high tidal volumes, which is a clinically relevant model of mechanical stress lung injury. These data reveal that nmMLCK2 overexpression in the endothelium exacerbates lung injury in vivo in a sexually dimorphic and age-dependent manner.     

Demonstration of vasculogenic mimicry in astrocytomas and effects of Endostar on U251 cells

Angiogenesis is an important process for the cell growth of normal and tumor tissues. Vasculogenic mimicry (VM) is a newly described vascular network structure that was first described in aggressive melanomas. To find out whether VM also exists in astrocytomas and to examine its clinical significance, we studied 80 malignant astrocytoma samples using immunohistochemistry coupled with periodic acid-Schiff (PAS) staining. To explore the possible therapeutic methods of anti-VM formation, we cultured astrocytoma cells using three-dimensional Matrigel and investigated the effects of Endostar, an endothelial cell growth inhibitor, on astrocytoma cell growth, invasion, and VM formation. VM structures were found in 8 samples of malignant astrocytomas, seven of which were grade IV astrocytomas. Glioblastoma U251 cells cultured in Matrigel formed vessel-like loops and networks, mimicking the features of VM in vivo, whereas such structures were not found in cultured normal astrocytes or well-differentiated astrocytoma SHG44 cells. In addition, treatment with Endostar led to a dose- and time-dependent inhibition of proliferation and invasion of both U251and SHG44 cells, but VM formation by U251 cells in vitro was not prominently affected. In conclusion, VM is frequently detected in aggressive glioblastomas, and the presence of VM may constitute a new predictor for poor prognosis in astrocytoma patients. Although Endostar has broad anti-tumor effects due to anti-angiogenesis and anti-tumor cell mechanisms, its inhibitory effects on VM formation by U251cells in vitro are not remarkable.     

钠氢交换体1在星形细胞瘤中的表达及其与恶性程度的关系*

目的：检测人星形细胞瘤和正常脑组织中钠氢交换体1（ NHE1）的表达差异及其与恶性程度的关系,探 讨星形细胞瘤增殖、生长的分子机制。方法：收集人星形细胞瘤标本51 例,低、高级别星形细胞瘤组织分别为 22 例、29 例,以肿瘤周围相对正常脑组织作为对照。用H-E 染色进行诊断和分级,免疫组织化学和免疫印迹检 测肿瘤组织与正常脑组织中NHE1表达变化。结果：NHE1主要分布在对照组神经元和少量星形胶质细胞胞膜上; 在肿瘤组织中,NHE1分布在低级别星形细胞瘤细胞膜上,并强烈表达于高级别星形细胞瘤的胞质和胞膜上。与 对照组相比较,在低级别和高级别星形细胞瘤组织中NHE1表达上调,其中,恶性程度较高的高级别肿瘤相对于 恶性程度低的低级别肿瘤,NHE1的表达更为强烈。结论：NHE1在人星形细胞瘤组织中表达增强,其强度变化 与肿瘤的恶性程度有关。     

Proteomics of tumor-specific proteins in cerebrospinal fluid of patients with astrocytoma: Usefulness of gelsolin protein

Changes in cerebrospinal fluid (CSF) composition have been shown to accurately reflect pathological processes in the CNS, and are potential indicators of abnormal CNS states, such as tumor growth. To detect biomarkers in high-grade astrocytomas, the differential expression of proteins in the cerebrospinal fluid was analyzed from two cases each of diffuse astrocytoma (grade II), and glioblastoma (grade IV) using agarose 2-D gel electrophoresis (2-DE). It was found that the expression of gelsolin protein decreased with histological grade. To examine whether gelsolin is a useful indicator of tumor aggressiveness or patient outcome, its expression was further studied on immunohistochemistry in 41 formalin-fixed and paraffin-embedded astrocytomas. The positive cell rate of gelsolin in tumors was 59.4% in grade II, 30.0% in grade III and 29.4% in grade IV, respectively. Gelsolin expression was significantly lower in high-grade astrocytomas (grade III or IV) than in low-grade astrocytomas (grade II; P < 0.05). Moreover, in astrocytomas the overall survival of patients in the low-expression group was significantly poorer than in the high expression group ( P < 0.05). These data suggest that gelsolin is a prognostic factor in astrocytoma.     

Age-dependent divergent effects of OX40L treatment on the development of diabetes in NOD mice

Earlier, we have shown that GM-CSF derived bone marrow (BM) dendritic cells (G-BMDCs) can expand Foxp3⁺ regulatory T-cells (Tregs) through a TCR-independent, but IL-2 dependent mechanism that required OX40L/OX40 interaction. While some reports have shown suppression of autoimmunity upon treatment with an OX40 agonist, others have shown exacerbation of autoimmune disease instead. To better understand the basis for these differing outcomes, we compared the effects of OX40L treatment in 6-week-old pre-diabetic and 12-week-old near diabetic NOD mice. Upon treatment with OX40L, 6-week-old NOD mice remained normoglycemic and showed a significant increase in Tregs in their spleen and lymph nodes, while 12-week-old NOD mice very rapidly developed hyperglycemia and failed to show Treg increase in spleen or LN. Interestingly, OX40L treatment increased Tregs in the thymus of both age groups. However, it induced Foxp3⁺CD103⁺CD38^? stable-phenotype Tregs in the thymus and reduced the frequency of autoreactive Teff cells in 6-week-old mice; while it induced Foxp3⁺CD103^?CD38⁺ labile-phenotype Tregs in the thymus and increased autoreactive CD4⁺ T cells in the periphery of 12-week-old mice. This increase in autoreactive CD4⁺ T cells was likely due to either a poor suppressive function or conversion of labile Tregs into Teff cells. Using ex vivo cultures, we found that the reduction in Treg numbers in 12-week-old mice was likely due to IL-2 deficit, and their numbers could be increased upon addition of exogenous IL-2. The observed divergent effects of OX40L treatment were likely due to differences in the ability of 6- and 12-week-old NOD mice to produce IL-2.     

Deletion of chromosome arm 17p dna sequences in pediatric high-grade and juvenile pilocytic astrocytomas

In adults, loss of heterozygosity for DNA on 17p has been shown in high-grade anaplastic astrocytomas (AAs) and glioblastomas multiforme (GMs), and mutation of the TP53 tumor suppressor gene has been reported in all grades of astrocytomas. Little is known, however, about 17p deletion and TP53 mutation in juvenile pilocytic astrocytomas (JPAs), the most common low-grade tumors seen in children. To elucidate the genetic characteristics of pediatric high-grade astrocytomas and JPAs, we performed restriction fragment length polymorphism analysis with probes derived from 17p and TP53 mutational studies in 28 tumor specimens. Telomeric chromosome arm 17p markers 144-D6 and ABR were lost in 6 (75%) of 8 informative tumors classified as high-grade (7 AAs, 1 GM) and in 2 (10%) of 20 informative JPAs. Loss of 17p probes centromeric to the TP53 gene were also detected in 3 AAs and 5 JPAs. Four of the 6 (66%) JPAs with losses of 17p DNA sequences recurred rapidly despite aggressive therapy, whereas only 5 of the other 14 (36%) recurred. Mutation of the TP53 gene was detected by polymerase chain reaction and denaturing gradient gel electrophoresis in only 1 JPA and 1 AA. These tumors were also examined for MDM2 gene amplification as an alternate inactivation mechanism for TP53 gene function: no instances of alteration were identified. These results suggest that a gene or genes in addition to TP53 on 17p may be involved in the etiology or progression of high-grade astrocytomas and aggressive JPAs in children. Further, molecular genetic studies may be an important supplement to current clinical and radiologic data in predicting the outcome and guiding the therapy of children with aggressive and malignant astrocytomas.     

Malignancy grading of glial tumors. I. Astrocytomas

A total of 91 fibrillar, protoplasmic and gemistocytic astrocytomas, 56 pilocytic astrocytomas and 70 glioblastomas, surgically obtained from 1973 to 1979, were evaluated. A four-grade malignancy system was applied to the astrocytomas. The grading criteria for the astrocytomas included quantitative cell density, cellular and nuclear polymorphism, mitotic activity, proliferative changes in the vascular elements and degree of necrosis. Using these criteria it was possible to distinguish four grades. Astrocytoma grades 1 and 2 correspond to the rubric "low-grade astrocytoma" in the English nomenclature, grades 3 and 4 to "high-grade astrocytoma". From the 91 fibrillar, protoplasmic and gemistocytic astrocytomas there were 12, 29, 31 and 19 tumors in grades 1 to 4 respectively. The corresponding distribution for the 56 pilocytic astrocytomas was 20, 29, 6, 1. Median survival for the fibrillar, protoplasmic and gemistocytic group for malignancy grades 1-4 were 43.8, 33.5, 8.4 and 5.6 months respectively. The corresponding figures for the pilocytic astrocytomas grades 1-3 were greater than 66, greater than 69, and 20.0 months.     

Timing of p53 mutations during astrocytoma tumorigenesis

Using a combination of polymerase chain reaction and single-strandconformation polymorphism techniques (PCR-SSCP) we have analyzed78 brain tumor samples (70 primary and 8 metastatic) for thepresence of mutations in the conserved regions of the Tp53 (tumorp53) gene. We have found that only two groups, gilomas (exclusivelyin astrocytomas) and metastases, displayed Tp53 mutations. Threeof eight (37.5%) metastases showed a mutant Tp53 allele accompaniedby loss of the normal one. In contrast, the frequency of Tp53mutations in the primary brain tumors examined was lower (5.7%).Although we have examined different types of primary brain tumors,Tp53 mutations were exclusively observed in both, low and high-gradeastrocytomas (four of 24). The Tp53 mutations detected in astrocytictumors appear to be correlated with the malignancy grade. Thelow-grade astrocytomas were heterozygous for the mutation, whereasthe high-grade astrocytomas had affected the two Tp53 alleles,suggesting a two-steps model for inactivation of the p53 genein astrocytomas. Thus, single p53 mutation seems to occur ininitial stages of astrocytoma tumorigenesis; the later lostof the remaining wild-type allele appears associated with theprogression towards a more malignant stage.     

A modular and flexible ESC-based mouse model of pancreatic cancer

Genetically engineered mouse models (GEMMs) have greatly expanded our knowledge of pancreatic ductal adenocarcinoma (PDAC) and serve as a critical tool to identify and evaluate new treatment strategies. However, the cost and time required to generate conventional pancreatic cancer GEMMs limits their use for investigating novel genetic interactions in tumor development and maintenance. To address this problem, we developed flexible embryonic stem cell (ESC)-based GEMMs that facilitate the rapid generation of genetically defined multiallelic chimeric mice without further strain intercrossing. The ESCs harbor a latent Kras mutant (a nearly ubiquitous feature of pancreatic cancer), a homing cassette, and other genetic elements needed for rapid insertion and conditional expression of tetracycline-controlled transgenes, including fluorescence-coupled shRNAs capable of efficiently silencing gene function by RNAi. This system produces a disease that recapitulates the progression of pancreatic cancer in human patients and enables the study and visualization of the impact of gene perturbation at any stage of pancreas cancer progression. We describe the use of this approach to dissect temporal roles for the tumor suppressor Pten and the oncogene c-Myc in pancreatic cancer development and maintenance.     

Non-proliferating plasma cells detected in the salivary glands and bone marrow of autoimmune NOD.B10.H2b mice,a model for primary Sjögren’s syndrome

Autoantibody secreting plasma cells (PCs) are essential contributors in the development of autoimmune conditions such as primary Sjögren’s syndrome (pSS). Particularly, the long-lived PC subset residing in the bone marrow has shown to continuously produce autoantibodies, whilst remaining unaffected by immunosuppressive treatment. We have previously shown accumulation of potentially long-lived PCs in chronically inflamed salivary glands of pSS patients. In this study, we aimed to characterise the PC compartment in the salivary glands (the target organ for pSS) and bone marrow before the onset of the murine pSS like disease versus advanced diseases progression. Bromodeoxyuridine (BrdU) was incorporated to distinguish the long-lived PCs. Double immunohistochemical staining and immunofluorescence were then conducted on submandibular gland and bone marrow sections from 8- and 40-week-old mice to identify BrdU and CD138. BrdU⁺ cells were detected in the submandibular glands of 8-week-old mice, and observed within all focal infiltrates by 40 weeks of age. Most CD138⁺ PCs were however BrdU^? and located predominantly on the periphery of these infiltrates. This observation was verified through immunofluorescence. A comparable staining pattern was observed in the bone marrow of 8- and 40-week-old NOD.B10.H2b mice, where some of the CD138⁺ cells also expressed BrdU. Interestingly, megakaryocytes in the bone marrow of NOD.B10.H2b mice were detected in close proximity to CD138⁺ cells, illustrating a possible presence of PC survival niches. Our results demonstrate the presence and accumulation of potentially long-lived PCs in NOD.B10.H2b mice as the disease advances.     

Mechanical and material properties of cortical and trabecular bone from cannabinoid receptor-1-null (Cnr1−/−) mice

The endocannabinoid system is known for its regulatory effects on bone metabolism through the cannabinoid receptors, Cnr1 and Cnr2. In this study we analysed the mechanical and material properties of long bones from Cnr1^−/− mice on a C57BL/6 background. Tibiae and femora from 5- and 12-week-old mice were subjected to three-point bending to measure bending stiffness and yield strength. Elastic modulus, density and mineral content were measured in the diaphysis. Second moment of area (MOA₂), inner and outer perimeters of the cortical shaft and trabecular fractional bone volume (BV/TV) were measured using micro-CT. In Cnr1^−/− males and females at both ages the bending stiffness was reduced due to a smaller MOA₂. Bone from Cnr1^−/− females had a greater modulus than wild-type controls, although no differences were observed in males. BV/TV of 12-week-old Cnr1^−/− females was greater than controls, although no difference was seen at 5-weeks. On the contrary, Cnr1^−/− males had the same BV/TV as controls at 12-weeks while they had significantly lower values at 5-weeks. This study shows that deleting Cnr1 decreases the amount of cortical bone in both males and females at 12-weeks, but increases the amount of trabecular bone only in females.     

Phenotypic characterization of the infiltrating immune cells in normal prostate, benign nodular prostatic hyperplasia and prostatic adenocarcinoma

Background

Immune cell infiltrate is a constant feature in normal prostate, benign nodular prostatic hyperplasia and prostatic adenocarcinoma. This study elaborates on the cells of the immune system present in normal prostate, benign nodular prostatic hyperplasia and prostatic adenocarcinoma.

Hypothesis

Here, we hypothesized that “the development of benign nodular prostatic hyperplasia and prostatic adenocarcinoma is associated with numeric alterations of the immune cell infiltrate”.

Materials and methods

A total of 50 transurethral prostatic resection specimens, each entailing normal prostate, benign nodular prostatic hyperplasia and high grade prostatic adenocarcinoma were evaluated for the density and phenotype of the immune cells using immunohistological methods and mouse monoclonal antibodies decorating T cells (CD3), histiocytes (CD68) and B lymphocytes (CD20).

Results

Immune cell infiltrate was composed of T cells, histiocytes and B-lymphocytes. CD⁺3 T lymphocytes and CD68⁺ cells were the predominant cell populations. We observed variations in the density of the immune cells among the normal prostate, benign nodular prostatic hyperplasia and high grade prostatic adenocarcinoma. Compared with normal prostate, benign nodular prostatic hyperplasia had a statistically significant high density of immune cells (3.4 ± 0.4versus 13.5 ± 1.0, P < 0.00). In contrast, a significant decrease in the counts of these cells was observed in high-grade prostatic adenocarcinoma compared to benign nodular prostatic hyperplasia (13.5 ± 1.0 versus 5.2 ± 0.3, P < 0.01).

Conclusions

The increased density of immune cells (predominantly CD⁺3 T cells) in benign nodular prostatic hyperplasia suggests that the initial response to cellular damage is mediated by cell-mediated immunity. The decreased density of immune cells in high-grade prostatic adenocarcinoma may reflect immunosuppression. The underlying mechanisms of these numeric variations are open for further investigations.     

Lack of nrf2 results in progression of proliferative lesions to neoplasms induced by long-term exposure to non-genotoxic hepatocarcinogens involving oxidative stress

To explore the role of oxidative stress in chemical carcinogenesis driven by non-genotoxic mechanisms, nrf2-deficient (nrf2^−/−) and nrf2-wild-type (nrf2^+/+) mice were exposed to pentachlorophenol (PCP) at concentrations of 600 or 1200 ppm for 60 weeks, or piperonyl butoxide (PBO) at concentrations of 3000 or 6000 ppm in the diet for 52 weeks, respectively. Additional studies were performed to examine 8-hydroxydeoxyguanosine (8-OHdG) levels in liver DNA and hepatotoxicological parameters in serum following 8 weeks of exposure of each group to PBO at the same doses as in the long-term study. Exposure to 600 ppm PCP caused cholangiofibrosis (CF) only in nrf2^−/− mice, while 1200 ppm PCP induced CF in both genotypes. Moreover, cholangiocarcinomas were found with significant incidence only in nrf2^−/− mice treated with 1200 ppm PCP. Short-term exposure to 6000 ppm PBO caused significant elevation of 8-OHdG levels in both genotypes, while exposure to 3000 ppm caused a significant increase in 8-OHdG only in nrf2^−/− mice. There were no inter-genotype changes in the incidences of regenerative hepatocellular hyperplasia (RHH) following long-term exposure to PBO. However, the incidence and multiplicity of hepatocellular adenomas, especially those observed in RHH, were much higher in nrf2−/− mice treated with 6000 ppm PBO than in nrf2+/+ mice treated with 6000 ppm PBO. Therefore, oxidative stress generated through PCP or PBO metabolism may promote the proliferation and progression of preneoplastic lesions to neoplasms.     

Somatic neurofibromatosis type 1 (NF1) inactivation characterizes NF1-associated pilocytic astrocytoma

Low-grade brain tumors (pilocytic astrocytomas) arising in the neurofibromatosis type 1 (NF1) inherited cancer predisposition syndrome are hypothesized to result from a combination of germline and acquired somatic NF1 tumor suppressor gene mutations. However, genetically engineered mice (GEM) in which mono-allelic germline Nf1 gene loss is coupled with bi-allelic somatic (glial progenitor cell) Nf1 gene inactivation develop brain tumors that do not fully recapitulate the neuropathological features of the human condition. These observations raise the intriguing possibility that, while loss of neurofibromin function is necessary for NF1-associated low-grade astrocytoma development, additional genetic changes may be required for full penetrance of the human brain tumor phenotype. To identify these potential cooperating genetic mutations, we performed whole-genome sequencing (WGS) analysis of three NF1-associated pilocytic astrocytoma (PA) tumors. We found that the mechanism of somatic NF1 loss was different in each tumor (frameshift mutation, loss of heterozygosity, and methylation). In addition, tumor purity analysis revealed that these tumors had a high proportion of stromal cells, such that only 50%–60% of cells in the tumor mass exhibited somatic NF1 loss. Importantly, we identified no additional recurrent pathogenic somatic mutations, supporting a model in which neuroglial progenitor cell NF1 loss is likely sufficient for PA formation in cooperation with a proper stromal environment.NF1 is one of the most common autosomal dominant tumor predisposition syndromes in which affected individuals develop brain tumors. In this regard, 15%–20% of children with NF1 develop World Health Organization (WHO) grade I pilocytic astrocytomas (PAs) (Listernick et al. 1994). These low-grade glial neoplasms typically arise in children <7 yr of age and most commonly occur in the optic pathway (optic nerves, chiasm, and tracts) or in the brainstem (Listernick et al. 1997). Similar to other tumor predisposition syndromes, children with NF1 are born with one mutated, nonfunctional copy of the NF1 gene, such that loss of the remaining allele in appropriate progenitor cells enables tumorigenesis. Consistent with this “two hit” hypothesis, previous studies of NF1-associated PA (NF1-PA) have demonstrated loss of heterozygosity at the DNA level (Kluwe et al. 2001; Gutmann et al. 2003) and loss of NF1 protein (neurofibromin) expression (Gutmann et al. 2000).While NF1 loss in neuroglial progenitors is necessary for PA formation in individuals with NF1, genetically engineered mice (GEM) with conditional loss of Nf1 gene expression in neuroglial progenitor cells fail to develop brain tumors (Bajenaru et al. 2002; Zhu et al. 2005). This failure to develop gliomas reflects the need for cooperating Nf1^+/− non-neoplastic cells in the tumor microenvironment. In this regard, similar to children with NF1 harboring one nonfunctional and one functional NF1 allele in every cell of their bodies, Nf1^+/− mice (one functional and one inactivated Nf1 allele) with absent neuroglial progenitor Nf1 expression develop optic gliomas with nearly 100% penetrance (Bajenaru et al. 2003). Similar to their human counterparts, these murine brain tumors exhibit low levels of proliferation, increased numbers of endothelial cells and microglia, and nuclear pleomorphism (Bajenaru et al. 2005; Kim et al. 2010).Interestingly, these mouse optic gliomas do not fully recapitulate the classic histopathological features of the human tumors, in that they lack Rosenthal fibers and eosinophilic granular bodies (Louis et al. 2007), raising the intriguing possibility that other genetic alterations exist in human NF1-PA. The purpose of the current study was to employ advanced whole-genome sequencing technologies to establish the genomic landscape of human NF1-PA to facilitate the development of improved approaches to the diagnosis and management of these brain tumors.     

Promoter hypermethylation-mediated down-regulation of LATS1 and LATS2 in human astrocytoma

LATS1 and LATS2 are tumor suppressor genes implicated in the regulation of cell cycle, but their methylation statuses are still unknown in human astrocytoma. Here, we found that the promoter hypermethylation frequencies of LATS1 and LATS1 were 63.66% (56/88) and 71.5% (63/88) in 88 astrocytomas by methylation-specific PCR. But no methylation of LATS1 and LATS2 promoter was detected in the 10 normal brain tissues. There was an increased methylation frequency of LATS1 and LATS2 with the malignant development of astrcytoma. By real-time PCR, the mRNA expression of LATS1 or LATS2 was detected significantly decreased in different pathological grade astrocytomas (P < 0.05). And the mRNA levels of LATS1 and LATS2 in astrocytomas with hypermethylation were both significantly (P < 0.01) lower than those without methylation. The methylation of LATS1 and LATS2 was detected in U251 and SHG-44 cell lines, and 5-aza-deoxycytidine could restore their expression to induce cell apoptosis. Our results suggested that LATS1 and LATS2 mRNA was down-regulated in astrocytoma by hypermethylation of the promoter. The methylation and mRNA expression of LATS1 and LATS2 may provide useful clues to the development of the diagnostic assays for astrocytoma. Our results also suggested that LATS1 and LATS2 may be a useful target for astrocytoma therapy.     

Size distribution of serum extracellular vesicles in mice with atherosclerosis

Background and aimsAtherosclerosis is a prominent vascular lesion, and potentially causing ischemic alterations in the brain and heart. Recent studies have reported that physiological and pathological alterations in atherosclerosis and extracellular vesicles (EV) are related. This study aimed to investigate the association between the extent of atherosclerotic lesions and the number of serum EVs in a mouse model of atherosclerosis (wild-type).MethodsEighteen 3-week-old C57BL/6 N male mice(wild-type) were purchased. Twelve mice were fed a 45% high-fat diet (HFD) for six months. Six mice were provided standard laboratory chow for six months. The entire aorta, from the aortic sinus to the division of the iliac artery, was dissected out from each mouse. Furthermore, the degree of atherosclerosis was microscopically determined. Serum EVs were quantified by size via nanoparticle tracking analysis.ResultsThe number of EVs in the high-atherosclerotic score group (1.43 × 10⁹) was higher than that in the low- atherosclerotic score group (0.7 × 10⁹) in the range of 211.5–222.5 nm (p = 0.033).ConclusionsEnumeration of EVs is a potential method of detecting atherosclerosis.