Functional evidence for a second tumor suppressor gene on human chromosome 17.

The development and progression of human tumors often involves inactivation of tumor suppressor gene function. Observations that specific chromosome deletions correlate with distinct groups of cancer suggest that some types of tumors may share common defective tumor suppressor genes. In support of this notion, our initial studies showed that four human carcinoma cell lines belong to the same complementation group for tumorigenic potential. In this investigation, we have extended these studies to six human soft tissue sarcoma cell lines. Our data showed that hybrid cells between a peripheral neuroepithelioma (PNET) cell line and normal human fibroblasts or HeLa cells were nontumorigenic. However, hybrid cells between the PNET cell line and five other soft tissue sarcoma cell lines remained highly tumorigenic, suggesting at least one common genetic defect in the control of tumorigenic potential in these cells. To determine the location of this common tumor suppressor gene, we examined biochemical and molecular polymorphic markers in matched pairs of tumorigenic and nontumorigenic hybrid cells between the PNET cell line and a normal human fibroblast. The data showed that loss of the fibroblast-derived chromosome 17 correlated with the conversion from nontumorigenic to tumorigenic cells. Transfer of two different chromosome 17s containing a mutant form of the p53 gene into the PNET cell line caused suppression of tumorigenic potential, implying the presence of a second tumor suppressor gene on chromosome 17.     

Syncollin is differentially expressed in rat proximal small intestine and regulated by feeding behavior

Gradients of gene expression are maintained along the proximal-distal axis of the mammalian small intestine despite a continuously regenerating epithelium. To study the molecular mechanisms responsible for this phenomenon, we utilized a subtractive hybridization strategy to isolate genes differentially expressed in the duodenum but not ileum. We isolated and sequenced 15 clones. The clones were fragments of genes encoding lipases, proteases, and an esterase. A novel clone was characterized and subsequently shown to encode syncollin, a secretory granule protein that binds to syntaxin in a calcium-sensitive manner. RT-PCR and S1 nuclease protection assay were used to clarify the 5'-end of syncollin. Syncollin was expressed in the rat pancreas, spleen, duodenum, and colon. In situ hybridization localized syncollin expression in the pancreas to acinar cells and in the duodenum to villus epithelial cells.     

Establishment and characterization of a cell line of congenital primitive neuroectodermal tumor of soft tissue.

A new human cell line, termed Muraoka, has been established from the recurrent tumor of a case of congenital primitive neuroectodermal tumor (PNET) arising at the temporofacial region of a male infant. The microscopic findings of this cell line were epithelioid, and the xenografted tumor in a nude mouse consisted of the malignant epithelioid cells. Immunohistochemically, the cells were positive for neuron-specific enolase, S-100 protein, carcinoembryonic antigen, cytokeratin, epithelial membrane antigen, and glial fibrillary acidic protein. These findings were quite similar to those of the epithelioid cells in the original tumor and of the xenografted tumor cells. Neither chromosomal abnormalities nor N-myc amplification were observed. Morphological differentiation after treatment with N6-2'-O-dibutyryladenosine 3':5'-cyclic monophosphate (Bt2-cAMP), all-trans-retinoic acid (RA), prostaglandin E1 (PGE1), and 5-bromo-2'-deoxyuridine (BrdU) showed two different results. Bt2-cAMP and PGE1 induced neuronal differentiation with the extension of neurites, whereas RA and BrdU predominantly induced Schwannian differentiation (flat cells). In these respects, the cell line Muraoka seems to be useful for studying characteristics of PNET as well as for developing the new treatments against such tumors.     

Cerebral primitive neuroectodermal tumor in an adult male. A case report

BACKGROUND: Primitive neuroectodermal tumors (PNETs) are very rare. Malignant tumors of the cerebrum in young individuals are composed predominantly of undifferentiated cells, with moderate differentiation along either neuronal or glial lines. To our knowledge, cerebral PNETs in adults are extraordinarily rare and have been reported in only 11 cases, with little cytologic documentation in the literature. The cytopathologic, immunohistochemical and ultrastructural features of cerebral PNET arising in an adult male are presented. CASE: A cystic tumor, on computed tomography and magnetic resonance imaging, arose from the left frontal lobe in a 39-year-old man and contained histopathologic features of PNET. Specimens obtained from surgery revealed the presence of an undifferentiated type of PNET with moderate neuronal and glial differentiation and mild characteristic findings of peripheral PNET. The cytologic and histologic specimens showed evidence of a scattered pattern of blastic and undifferentiated tumor cells and a neural arrangement with Homer-Wright-like rosettes. Immunohistochemically, the tumor cells were glial fibrillary acidic protein, neuron-specific enolase, synaptophysin and CD-99 positive and epithelial membrane antigen, S-100 protein and vimentin negative. Ultrastructurally, neither microtubular structures nor intermediate filaments, except neurosecretory granules, were found in the tumor cells. CONCLUSION: Both immunohistochemical and ultrastructural studies on cytologic and histologic slides were important for the diagnosis of PNET because of establishing not only undifferentiated tumor cells but also neural and glial differentiation.     

Immunohistochemical localization of pancreatic secretory trypsin inhibitor in fetal and adult pancreatic and extrapancreatic tissues

Pancreatic secretory trypsin inhibitor (PSTI) has been thought to be only a secretory trypsin inhibitor of human pancreas, but the serum content of immunoreactive PSTI is elevated without pancreatic disease. Using the peroxidase-antiperoxidase method, immunoreactive cells for PSTI were found in human pancreas, stomach, duodenum, appendix, colon and urinary tract of both fetus and adult, adult gall bladder, and fetal lung. PSTI-immunoreactive cells were identified in fetal pancreas at the tenth gestational week, and in extrapancreatic tissues at the sixteenth (gastrointestinal and urinary tract) and twentieth weeks (lung). PSTI-immunoreactive cells of fetal lung were present in neuroepithelial bodies. Strongly positive cells in fetal duodenum were argyrophilic and resembled endocrine cells. Immunohistochemical study was also performed on tissues associated with inflammatory diseases of gastrointestinal tract. The distribution pattern of immunoreactive cells in the stomach varied in accordance with chronic gastritis. Immunoreactive cells were also found in endocrine micro-nests and in a carcinoid tumor associated with fundic gastritis. These results suggest that PSTI may play some physiological role other than secretory trypsin inhibition of the pancreas.     

The role of viral hemorrhagic septicemia virus (VHSV) NV gene in TNF-α- and VHSV infection-mediated NF-κB activation

The role of viral hemorrhagic septicemia virus (VHSV) NV gene in nuclear factor-κB (NF-κB) activation was investigated. Epithelioma papulosum cyprini (EPC) cells pre-treated with tumor necrosis factor (TNF)-α showed a strong resistance against VHSV infection, but cells treated with TNF-α after VHSV infection showed no resistance, suggesting that immediate early TNF-α-mediated responses inhibit VHSV replication. Activation of NF-κB is a key step in TNF-α-mediated immunomodulatory pathways. In this study, activation of NF-κB by TNF-α exposure was inhibited in EPC cells harboring NV gene expressing vectors, indicating that the NV gene of VHSV can suppress TNF-α-mediated NF-κB activation. Furthermore, the NV gene knock-out recombinant VHSV (rVHSV-ΔNV-EGFP) induced significantly higher NF-κB activity in EPC cells than wild-type VHSV, suggesting that VHSV adopted a strategy to suppress early activation of NF-κB in host cells through and NV gene.     

A vaccinia virus deletion mutant reveals the presence of additional inhibitors of NF-kappaB

The classical nuclear factor kappa B (NF-κB) signaling pathway is an important regulator of inflammation and innate immunity that is activated by a wide variety of stimuli, including virus infection, tumor necrosis factor alpha (TNF-α), and interleukin 1β (IL-1β). Poxviruses, including vaccinia virus (VV) and ectromelia virus, encode multiple proteins that function in immune evasion. Recently, a growing number of genes encoded by poxviruses have been shown to target and disrupt the NF-κB signaling pathway. To determine if additional gene products that interfere with NF-κB signaling existed, we used a vaccinia virus deletion mutant, VV811, which is missing 55 open reading frames lacking all known inhibitors of TNF-α-induced NF-κB activation. Immunofluorescence analysis of HeLa cells treated with TNF-α and IL-1β revealed that NF-κB translocation to the nucleus was inhibited in VV811-infected cells. This was further confirmed through Western blotting of cytoplasmic and nuclear extracts for NF-κB. Additionally, VV811 infection inhibited TNF-α-induced IκBα degradation. In contrast to vaccinia virus strain Copenhagen (VVCop)-infected cells, VV811 infection resulted in the dramatic accumulation of phosphorylated IκBα. Correspondingly, coimmunoprecipitation assays demonstrated that the NF-κB-inhibitory IκBα-p65-p50 complex was intact in VV811-infected cells. Significantly, cells treated with 1-β-d-arabinofuranosylcytosine, an inhibitor of poxvirus late gene expression, demonstrated that an additional vaccinia virus late gene was involved in the stabilization of IκBα. Overall, this work indicates that unidentified inhibitors of NF-κB exist in vaccinia virus. The complex inhibition of NF-κB by vaccinia virus illustrates the importance of NF-κB activation in the antiviral response.     

Cushing Syndrome Secondary to A Thymic Carcinoid Tumor Due to Multiple Endocrine Neoplasia Type 1

ObjectiveTo present an Iranian patient with a nonclassic form of multiple endocrine neoplasia type 1 (MEN 1) who presented with ectopic Cushing syndrome (CS) secondary to a corticotropin (ACTH)-producing thymic neuroendocrine tumor (NET), recurrent renal stones, and a giant cell granuloma of the jaw due to primary hyperparathyroidism (PHPT) without involvement of the pituitary or pancreas.MethodsRelevant imaging and hormonal evaluations were performed. The patient was operated on 2 occasions for a thymic NET and on 3 occasions for PHPT. DNA from a peripheral blood sample was extracted for sequencing of the MEN1 gene.ResultHistopathologic evaluation of the thymic tumor removed during the first surgery showed an atypical carcinoid tumor with a Ki-67 labeling index of 5%. Evaluation after the second surgery revealed an invasive carcinoid tumor with a Ki-67 labeling index of 30%.Parathyroid pathology was suggestive of glandular hyperplasia. Menin gene sequencing revealed a novel frameshift mutation c.1642_1648dup in exon 10.ConclusionThis case of MEN 1 is unusual because most thymic NETs in MEN 1 are nonfunctional, and secretion of ACTH or other ectopic hormones rarely occurs. In patients presenting with thymic NETs, the possibility of MEN 1 should be considered, especially in the presence of hyperparathyroidism. This case also demonstrates that the behavior of thymic NETs can change over time from slow-growing tumors to highly invasive neoplasia, and that ectopic ACTH can be produced by these tumors in the context of MEN 1. (Endocr Pract. 2011;17:e92-e96)     

Ghrelin expression in neuroendocrine tumours of the gastrointestinal tract with multiple endocrine neoplasia type 1.

Ghrelin is a novel gastrointestinal-brain hormone that was first described by Kojima et al. as a growth-hormone-releasing peptide. It can be isolated and purified from different tissues. Evidence of antiproliferative effects in neoplastic cells (binding to normal and neoplastic tissues) supports the hypothesis that ghrelin also plays an important role in endocrine regulation. Whether ghrelin may be involved in formation of neuroendocrine tumours (NET) of the gastrointestinal tract (GIT) in cases of MEN-1 is under discussion. Over the last sixteen years, 227 patients with GIT NET were treated at our institution. Mutations of the menin gene were identified in twelve patients. Eleven of these tumours (islet cell tumours) were localized in the pancreas and one in the stomach. Tissues from these tumours were resected, fixed in formalin and embedded in paraffin. Sections were examined by immunohistochemistry with a primary antibody for ghrelin. Three out of twelve NET in MEN-1 patients (25%) showed ghrelin expression by immunohistochemistry. Comparison between ghrelin-positive and ghrelin-negative tumours regarding biological activity, morphological aspects and clinicopathological parameters shows no substantial differences. The reported incidence of ghrelin expression in NET of the gastrointestinal tract by MEN-1 was not seen in our patients. Whether or not ghrelin has an influence on neuroendocrine tumour development related to deficient menin-genes is unknown.     

Dual T cell receptor expressing CD8+ T cells with tumor- and self-specificity can inhibit tumor growth without causing severe autoimmunity

The engineering of Ag-specific T cells by expression of TCR genes is a convenient method for adoptive T cell immunotherapy. A potential problem is the TCR gene transfer into self-reactive T cells that survived tolerance mechanisms. We have developed an experimental system with T cells that express two TCRs with defined Ag-specificities, one recognizing a tumor-specific Ag (LCMV-gp(33)), the other recognizing a self-Ag in the pancreas (OVA). By using tumor cells expressing high and low amounts of Ag and mice expressing high and low levels of self-Ag in the pancreas (RIP-OVA-Hi and RIP-OVA-Lo), we show that 1) tumor rejection requires high amount of tumor Ag, 2) severe autoimmunity requires high amount of self-Ag, and 3) if Ag expression on tumor cells is sufficient and low in the pancreas, successful adoptive T cell therapy can be obtained in the absence of severe autoimmunity. These results are shown with T cells from dual TCR transgenic mice or T cells that were redirected by TCR gene transfer. Our data demonstrate that the approach of adoptively transferring TCR redirected T cells can be effective without severe side effects, even when high numbers of T cells with self-reactivity were transferred.     

Primitive neuroectodermal tumor of the kidney. A report of two cases diagnosed by fine needle aspiration cytology

BACKGROUND: Primitive neurocetodermal tumors (PNETs) constitute a family of neoplasms of presumed neuroectrodermal origin most often presenting as bone or soft tissue masses. There are very few reported cases of PNET of the kidney and none diagnosed by fine needle aspiration cytology (FNAC), to the best of our knowledge, in the world literature. We present two cases of renal PNET diagnosed on cytology. CASES: Two patients with renal masses were diagnosed as having PNET on FNAC. Cytologically the tumors showed a dispersed population of malignant small round cells with focal rosette formation and perivascular arrangement of tumor cells. Immunohistochemistry on the cell blocks in both cases showed strong membrane positivity for CD99 (MIC2). Cytogenetic studies in both cases showed the characteristic t(11;22)(q24;q12) translocation, with additional chromosomal abnormalities in case 2. CONCLUSION: PNET of the kidney is a distinct entity and can be diagnosed on fine needle aspiration smears and confirmed with immunohistochemistry and cytogenetic studies. A diagnosis of PNET must be included in the differential diagnosis of renal masses in adolescents and young adults.     

Peripheral primitive neuroectodermal tumor of the vulva: report of a case with imprint cytology.

BACKGROUND: Peripheral primitive neuroectodermal tumor (PNET) of the vulva is an extremely rare disease, and, to our knowledge, only two cases have been previously reported. CASE: A 45-year-old woman presented with a mass in the right labium major. Three years after removal of the tumor, she noticed a new lesion in the same place and underwent a partial vulvectomy. The imprint cytology of the recurrent tumor showed a monomorphic appearance, composed of small round cells with scant cytoplasm against a hemorrhagic background. These tumor cells were loosely connective, but rosettelike structures were observed focally. On pathologic examination, the neoplasm was composed of small round tumor cells showing sinusoidal, diffuse or micropapillary growth. Immunohistochemically, the neoplastic cells stained positively for neuron-specific enolase, vimentin and HBA 71 and negatively for cytokeratin, HBA 45 and muscle-specific actin. The morphologic characteristics of the disease were well expressed in the imprint cytology, and this influenced the selection of immunohistochemical studies. CONCLUSION: Cytologic examination for vulvar tumors, even imprint cytology, can be a useful tool in obtaining an accurate pathologic diagnosis of a rare disease, such as peripheral PNET.     

Mixed osteoclastic/pleomorphic giant cell tumor of the pancreas: a case report

BACKGROUND: Mixed giant cell tumor (MGCT) of the pancreas is a rare malignant neoplasm. The tumor contains pleomorphic giant cells (PGC), pleomorphic mononuclear cells (PMC) and osteoclastic giant cells (OGC). We describe the first fine needle aspiration biopsy (FNAB) diagnosis of this tumor. CASE: A 76-year-old woman was discovered (on imaging studies) to have an apparently inoperable mass in the head of the pancreas. Computed tomography-guided FNAB showed a malignant neoplasm with features of an MGCT. PGC/PMC, OGC and spindle cells were present. The PGC/PMC expressed epithelial antigens, pancytokeratin, CAM 5.2, AE1/AE3 and epithelial membrane antigen (EMA). The spindle cells focally stained for EMA. OGC were negative for the epithelial antigens. OGC, PGC/PMC and the spindle cells were positive for the mesenchymal marker vimentin. CONCLUSION: FNAB was instrumental in making the diagnosis of a rare pancreatic tumor, MGCT. Immunocytochemistry was helpful in making a definitive diagnosis and suggested that MGCT is a carcinosarcoma like neoplasm. The morphology and immunocytochemical profile raise the possibility that osteoclastic giant cell tumor and pleomorphic giant cell tumor may be different morphologic and biologic expressions of the same tumor.     

RECS1负调控肿瘤坏死因子受体2介导的NF-κB激活

RECS1(responsive to centrifugal force and shear stress gene 1)是一血液剪切力应答蛋白.RECS1基因敲除的小鼠年老时易患主动脉囊性中层坏死并表现有大动脉扩张症,暗示RECS1可能参与调控血管的发育重塑.免疫组化分析发现,RECS1基因敲除(RECS1 knockout, RECS1 KO)的小鼠主动脉基质金属蛋白酶-9（matrix metalloproteinase-9,MMP-9）的表达水平明显提高,但RECS1的结构与功能及相关作用机理仍不清楚.研究发现,RECS1是肿瘤坏死因子受体2（tumor neucrosis factor receptor 2, TNFR2）的结合蛋白质.报告基因检测实验表明,RECS1能特异地抑制TNFR2特异的激动性抗体或过量表达TNFR2诱导的核转录因子-κB（nuclear factorκB,NF-κB）活化.NPLY模体缺失突变的RECS1不能结合TNFR2,并丧失对TNFR2介导NF-κB活化的抑制能力.稳定表达RECS1的MEFS细胞中,TNFR2特异的激动性抗体诱导的IκB (inhibitor of NF-κB)降解和NF-κB靶基因白介素-6（interleukin-6,IL-6）的表达均受到明显抑制.该研究揭示了RECS1通过与TNFR2的相互作用,负调控TNFR2介导肿瘤坏死因子信号传递的新功能及RECS1参与血管发育重塑调控的可能机制.     

Anticancer effects of 15d-prostaglandin-J2 in wild-type and doxorubicin-resistant ovarian cancer cells: novel actions on SIRT1 and HDAC

15-Deoxy-delta-12,14-prostaglandin-J(2) (15d-PGJ(2)), an arachidonic metabolite and a natural PPARγ agonist, is known to induce apoptosis in tumor cells. In this study, we investigated new therapeutic potentials of 15d-PGJ(2) by determining its anticancer effects in wild-type and doxorubicin-resistant ovarian carcinoma cells. Despite high expression of resistance-inducing genes like MDR1, Bcl2 and Bcl-xl, 15d-PGJ(2) strongly induced apoptosis in doxorubicin-resistant (A2780/AD) cells similar to the wild-type (A2780). This was found to be related to caspase-3/7- and NF-κB pathways but not to its PPARγ agonistic activity. 15d-PGJ(2) also was able to reduce the doxorubicin resistance of A2780/AD cells at low doses as confirmed by the inhibition of gene expression of MDR1 (p-glycoprotein) and SIRT1 (a drug senescence gene). We also investigated effects of 15d-PGJ(2) on cell migration and transformation using a wound-healing assay and morphological analyses, respectively. We found that 15d-PGJ(2) inhibited migration most likely due to NF-κB inhibition and induced transformation of the round-shape A2780/AD cells into elongated epithelial cells due to HDAC1 inhibition. Using a 15d-PGJ(2) analog, we found the mechanism of action of these new activities of 15d-PGJ(2) on SIRT1 and HDAC1 gene expressions and enzyme activities. In conclusion, the present study demonstrates that 15d-PGJ(2) has a high therapeutic potential to kill drug-resistant tumor cells and, the newly described inhibitory effects of this cyclo-oxygenase product on SIRT1 and HDAC will provide new opportunities for cancer therapeutics.     

EB病毒潜伏膜蛋白1通过结合TRAFs调控NF-κB

为了探讨EB病毒潜伏膜蛋白1(LMP1)的致瘤机制,对鼻咽癌中LMP1激活重要的核转录因子NF-κB机制进行了研究.首先,采用免疫共沉淀-蛋白质印迹在稳定表达LMP1的鼻咽癌细胞系HNE2-LMP1中证实LMP1与TRAF1,2,3结合形成免疫共沉淀复合物,进一步以野生型LMP1及其三种突变体的鼻咽癌细胞系LMP1（野生型,wt）、HNE2-LMP1 del187～351(CTAR1缺失型)、HNE2-LMP1(1～231)(CTAR2缺失型)、HNE2-LMP1(1～187)(羧基端胞浆区缺失型)、HNE2-pSG5(空白载体型)为材料,结合NF-κB报道基因质粒（pGL2-NF-κB-luc）的荧光素酶活性表达分析NF-κB的活性,证实:较之母细胞, 野生型LMP1活化NF-κB达13.8倍, LMP1(1～187)几乎不活化NF-κB,LMP1(1～231)活化NF-κB达4.9倍, LMP1(del187～351)活化NF-κB达9.1倍;TRAF1过表达升高LMP1(wt)及LMP1(1～231)介导的NF-κB活性,而对LMP1(del 187～351)活化NF-κB无影响;TRAF3过表达或TRAF3负显性突变体抑制LMP1(wt)及LMP1(1～231)介导的NF-κB活性,而不影响LMP1(del 187～351)活化NF-κB; TRAF2过表达升高LMP1(wt)、LMP1 (1～231)及LMP1(del 187～351)介导的NF-κB活性.这些结果表明：鼻咽癌中LMP1通过TRAF1、TRAF2或TRAF3调控NF-κB,TRAF1和TRAF3主要通过CTAR1发挥作用,TRAF2的作用主要是通过CTAR1和CTAR2介导的.