Seropositivity for NT5c1A antibody in sporadic inclusion body myositis predicts more severe motor, bulbar and respiratory involvement

OBJECTIVES

To explore phenotypic differences between individuals with sporadic inclusion body myositis (sIBM) who are seropositive for the NT5c1A antibody compared with those who are seronegative.

METHODS

Cross-sectional clinical, serological and functional analysis in 25 consecutive participants with sIBM.

RESULTS

All participants met criteria for clinically defined or probable sIBM. 18 of 25 participants with sIBM (72%) were seropositive for the NT5c1A antibody. No differences between median age and duration of illness between the two groups were seen. Females have higher odds of being seropositive (OR=2.30). Participants with seropositive sIBM took significantly longer to get up and stand (p=0.012). There were no significant differences between the two groups in terms of distance covered on a 6 min walk. Seropositive participants were more likely to require assistive devices such as a walker or wheelchair for mobility (OR=23.00; p=0.007). A number of secondary (exploratory) outcomes were assessed. NT5c1A seropositive sIBM cases had lower total Medical Research Council (MRC) sum score and MRC sum score on the right (p=0.03 and 0.02, respectively). Participants with the NT5c1A antibody were significantly more likely to have symptoms of dysphagia (OR=10.67; p=0.03) and reduced forced vital capacity (p=0.005). Facial weakness occurred in 50% of seropositive participants while it was only seen in 14% of seronegative participants.

CONCLUSIONS

Even though the small sample size limits definite conclusions, our cross-sectional study showed seropositivity to the NT5c1A antibody is associated with greater motor and functional disability in sIBM. The study also suggests more prominent bulbar, facial and respiratory involvement in individuals positive for NT5c1A antibodies.

Regulation of human neurotropic JCV in colon cancer cells

BACKGROUND

Recently, the genome of the human polyomavirus, JC (JCV), and expression of its early and late regulatory proteins (T-antigen and agnoprotein) have been demonstrated in neoplastic cells of colonic cancer cases.

MATERIALS AND METHODS

Regulation of JCV was investigated in a human colon cancer cell line (SW480) and compared to a human glioblastoma cell line (U87-MG) that is permissive for JCV replication.

RESULTS

SW480 cells supported basal transcription of both early and late JCV promoters. The expression of TCF-4, a component of Wnt signaling, modulated JCV transcription in a cell type-specific manner. Both TCF-4 and T-antigen bound to the JCV promoter region and bound to each other. In addition, the expression of TCF-4 caused a decrease in the ability of the T-antigen to stimulate viral DNA replication in U87-MG cells.

CONCLUSION

Wnt pathway signaling proteins and T-antigen interact to regulate JCV in colonic epithelial cells.

Detection of JC virus DNA sequences and expression of viral T antigen and agnoprotein in esophageal carcinoma

BACKGROUND

The human polyomavirus JC virus (JCV) causes progressive multifocal leukoencephalopathy. Subclinical infection with JCV occurs in 85-90% of the population worldwide. The virus usually remains latent but can reactivate under immunosuppressive conditions, resulting in progressive multifocal leukoencephalopathy. JCV is oncogenic in experimental animals and is associated with human brain tumors. JCV is found in normal mucosa of the gastrointestinal tract, and some colon carcinomas express the oncogenic JCV T-antigen protein. The objective of this study was to examine the presence of JCV DNA sequences and JCV protein expression in normal and malignant human esophageal tissues.

METHODS

The authors examined the presence of JCV DNA sequences and protein expression in normal and malignant human esophageal tissues. Seventy well characterized biopsy specimens from patients with a spectrum of esophageal disorders were studied by immunohistochemistry, and 18 specimens were analyzed further by polymerase chain reaction amplification.

RESULTS

JC viral DNA was isolated from 11 of 13 normal esophageal biopsy specimens (85%) and from 5 of 5 esophageal carcinomas (100%). Using immunohistochemistry, JCV T antigen was detected in 10 of 19 carcinomas (53%), agnoprotein was detected in 8 carcinomas (42%), p53 tumor suppressor was detected in 11 carcinomas (58%), and beta-catenin was detected in 4 carcinomas (21%). Zero of 51 normal, benign, and premalignant esophageal samples expressed viral proteins. Laser-capture microdissection verified the presence and specificity of JCV DNA sequences. beta-Catenin and p53 were colocalized with JCV T-antigen in the nuclei of neoplastic cells.

CONCLUSIONS

The results provide evidence for infection of gastrointestinal tract cells by JCV and suggest a potential role of JCV in the development of upper digestive tract carcinomas.

Primary central nervous system lymphoma expressing the human neurotropic polyomavirus, JC virus, genome

B lymphocytes are known as a potential site for latency and reactivation of the human neurotropic polyomavirus, JC virus (JCV). In light of recent studies on the oncogenicity of JCV and the transforming ability of the JCV early protein, T antigen, we investigated the association of JCV with B-cell lymphomas of the central nervous system. Examination of 27 well-characterized clinical specimens by gene amplification and immunohistochemistry revealed the presence of DNA sequences corresponding to the JCV early genome and the late Agnoprotein in 22 samples and the JCV late genome encoding the viral capsid proteins in 8 samples. Expression of T antigen and that of Agnoprotein by immunohistochemistry were each detected in six specimens. No evidence of the production of viral capsid proteins was observed, ruling out productive infection of JCV in the tumor cells. The results from laser capture microdissection verified the presence of JCV T-antigen sequences in tumor cells with positive immunoreactivity to antibodies against the viral proteins T antigen and Agnoprotein. Due to previous reports demonstrating an association of the Epstein-Barr virus (EBV) with transformation of B lymphocytes, EBV DNA sequences and the EBV transforming protein, latent membrane protein 1 (LMP1), were analyzed in parallel. EBV LMP1 DNA sequences were detected in 16 of 23 samples, and LMP1 expression was detected in 16 samples, 5 of which exhibited positive immunoreactivity to JCV proteins. Double labeling demonstrated coexpression of JCV T antigen and EBV LMP1 in the same cells. The detection of the JCV genome in large numbers of B-cell lymphomas and its coexistence with EBV suggest a potential role for JCV in the pathogenesis of primary CNS lymphoma.

Evidence for Involvement of Transforming Growth Factor β1 Signaling Pathway in Activation of JC Virus in Human Immunodeficiency Virus 1–Associated Progressive Multifocal Leukoencephalopathy

Context.—Progressive multifocal leukoencephalopathy is a fatal demyelinating disease of the central nervous system frequently seen in patients with impaired immune systems, particularly acquired immunodeficiency syndrome. JC virus (JCV), a human neurotropic polyomavirus, is the etiologic infectious agent of this disease.

Objective.—The significantly higher incidence of progressive multifocal leukoencephalopathy in patients with acquired immunodeficiency syndrome than in patients with other immunosuppressive conditions suggests that molecular interactions between human immunodeficiency virus 1 and JCV, via the Tat protein, are responsible for the activation of the JCV enhancer/promoter and the development of progressive multifocal leukoencephalopathy. An indirect mechanism through activation of cytokines, such as transforming growth factor β1 and Smads 3 and 4, may also be responsible for the enhancement of JCV gene expression.

Design.—Immunohistochemical analysis in progressive multifocal leukoencephalopathy samples and chloramphenicol acetyl transferase assays on cell cultures were performed to corroborate this hypothesis.

Results.—The JCV capsid protein VP-1 was found in the nuclei of oligodendrocytes and in the nuclei and cytoplasm of bizarre astrocytes. Human immunodeficiency virus proteins, including p24 and Tat, were detected in the cytoplasm of astrocytes. Tat, but not p24, was detected in oligodendrocytes, suggesting that extracellular Tat accumulates in the nuclei of oligodendrocytes, where JCV gene transcription takes place. High levels of transforming growth factor β1 and Smads 3 and 4 were detected in JCV-infected oligodendrocytes. Results from in vitro studies confirm activation of the JCV early and late promoters by Smads 3 and 4.

Conclusions.—These observations support our model, suggesting that the induction of transforming growth factor β1 by human immunodeficiency virus 1 Tat can stimulate its downstream factors, including Smads 3 and 4, which in turn augment transcription of the JCV promoter in glial cells.

JC virus-induced changes in cellular gene expression in primary human astrocytes

Cell-type-specific transcription of the JC virus (JCV) promoter in glial cells initiates a series of events leading to viral replication in the brain and the development of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) in patients with neurologic complications due to infection with human immunodeficiency virus type 1. Here we employed an in vitro infection of primary cultures of human astrocytes to compare the transcriptional profile of cellular genes after JCV infection by using an oligonucleotide-based microarray of 12600 genes. Transcription of nearly 355 genes was enhanced and expression of 130 genes was decreased to various degrees. Many transcripts that were increased upon JCV infection were found to encode proteins with properties that suggest their involvement in cell proliferation, including cyclin A and cyclin B1; signaling pathways, such as transforming growth factor beta receptor 1, platelet-derived growth factor receptor and fibroblast growth factor family receptor; and other regulatory events, such as inflammatory responses, including cyclo-oxygenase-2 (Cox-2). Microarray-based data for several cell cycle-regulatory genes were further examined by using Western blot analysis of in vitro infected astrocytes harvested early and late during the infection. Results demonstrate that protein levels of all upregulated genes were found to increase at some point during the infection time course. In parallel, immunohistochemical assessment of cell cycle proteins, including cyclins A, B1, E, and Cdk2, showed positive staining of astrocytes within PML lesions of brain tissue from patients with neuro-AIDS. Microarray analysis was found to be a useful predictor of gene expression in infected cells; however, it may not directly correlate with protein levels during infection with JCV.

Association of human polyomavirus JCV with colon cancer: evidence for interaction of viral T-antigen and beta-catenin

Infection of the gastrointestinal tract by the human polyomavirus, JCV, which has been frequently detected in raw urban sewage, can occur via intake of contaminated water and food. In light of earlier reports on the tumorigenecity of JCV, we investigated the presence of the JCV genome and the expression of viral proteins in a collection of 27 well-characterized epithelial malignant tumors of the large intestine. Results from gene amplification revealed the presence of the viral early genome in 22 of 27 samples. Expression of the viral oncogenic early protein, T-antigen, and the late auxiliary protein, Agnoprotein, was observed in >50% of the samples. The absence of the viral capsid protein in the tumor cells excludes productive replication of the virus in neoplastic cells. Laser capture microdissection confirmed the presence of the JCV genome and expression of T-antigen in precancerous villous adenomas and regions of invasive adenocarcinoma. The ability of JCV T-antigen to interact with beta-catenin and the nuclear detection of beta-catenin in T-antigen-positive cells suggests dysregulation of the Wnt pathway in the tumor cells. The coproduction of T-antigen and beta-catenin in colon cancer cells enhanced transcription of the c-myc promoter, the downstream target of beta-catenin. These observations provide evidence for a possible association of JCV with colon cancer and suggest a novel regulatory role for T-antigen in the deregulation of the Wnt signaling pathway through beta-catenin in tumors of the gastrointestinal tract.

Detection of JC polyomavirus DNA sequences and cellular localization of T-antigen and agnoprotein in oligodendrogliomas

PURPOSE

Productive infection of the human neurotropic polyomavirus JCPyV in oligodendrocytes leads to the development of progressive multifocal leukoencephalopathy, a fatal demyelinating disorder of the central nervous system. In addition to its role in viral infection, JCPyV T-antigen can transform cells in vitro and induce tumors in experimental animals in the absence of viral DNA replication and late gene expression. The goal of this study is to examine the presence of JCPyV DNA sequences and viral antigens in a series of human oligodendrogliomas.

EXPERIMENTAL DESIGN

A total of 20 well-characterized oligodendrogliomas were examined for detection of the JCPyV genome by PCR and immunohistochemistry for expression of viral proteins.

RESULTS

Gene amplification has revealed the presence of JCPyV DNA sequences corresponding to the NH2-terminal of T-antigen in 15 of 20 samples. DNA sequences corresponding to late regions, which are responsible for production of the capsid protein, VP1, were detected in 14 of 20 samples. Sequencing of the viral control region determined the presence of JCPyV Mad-4 or JCPyV(CY) in these tumors. By immunohistochemistry, T-antigen expression was detected in the nuclei of tumor cells from 10 samples that also contained corresponding DNA sequences by PCR. Eleven of 20 tumors exhibited immunoreactivity for the late auxiliary gene product, agnoprotein. None of the samples showed immunoreactivity for the capsid proteins, ruling out productive infection of neoplastic cells by JCPyV.

CONCLUSIONS

Collectively, these observations provide new evidence in support of the association of the oncogenic human neurotropic JCPyV and oligodendrogliomas.

Correlation of fine needle aspiration cytology and its histopathology in diagnosis of breast lumps

This study was carried out to evaluate the accuracy of FNAC and the role of FNAC in palpable breast lumps for the early surgical management in out patient and inpatient basis. The study was carried out in Dhaka Medical College during the period of January-December, 2000. FNAC was performed on 310 patients presented with palpable breast lumps. Histopathology was available for 122 cases. Of them, cytologically diagnosed benign cases were 106, histologically 105 cases were proved so. There was false negative diagnosis in one case. All 14 cases diagnosed as malignant cytologically proved as such histologically. Two cases reported as suspicious for malignancy one of which were proved malignant histologically. False positive diagnosis was made in one case. FNAC of breast lump was found to be associated with increased diagnostic yields. It can be carried out safely as a preoperative diagnostic method in-patients with breast lumps mostly in out-patient department.

Insulin-like growth factor I receptor activity in human medulloblastomas

Medulloblastomas represent about 25% of all pediatric intracranial neoplasms. These highly malignant tumors arise from the cerebellum affecting mainly children between ages 5 and 15. Although the etiology of medulloblastomas has not yet been elucidated, several reports suggest that insulin-like growth factor I (IGF-I) may contribute to the development of these tumors. Results of this study show that the majority of cases examined were characterized by the abundant presence of the receptor for IGF-I (IGF-IR) protein (16 of 20 cases), and its major signaling molecule, insulin receptor substrate 1 (IRS-1; 15 of 20). Protein levels for IGF-IR and IRS-1, determined by Western blot and immunohistochemistry, were significantly higher in medulloblastoma biopsies than in control cerebellar tissue. By immunohistochemistry, 10 of 17 biopsies examined were also positive for the anti-pY1316 antibody staining that specifically recognizes the phosphorylated (active) form of the IGF-IR. These findings correlate with the fact that phosphorylated forms of the downstream-signaling molecules Erk-1, Erk-2, and Akt/protein kinase B were found in medulloblastoma biopsies but not in control cerebellar tissue. Importantly, there is a strong inverse correlation between biopsies that are positive for anti-pY1316 and for anti-Trk-C immunoreactivity. These observations direct our attention to the IGF-IR system as a potential therapeutic target in medulloblastomas and suggest a possibility of using the anti-pY1316 antibody as a potential prognostic marker for medulloblastomas.

Insulin receptor substrate 1 translocation to the nucleus by the human JC virus T-antigen

Insulin receptor substrate 1 (IRS-1) is the major signaling molecule for the insulin and insulin-like growth factor I receptors, which transduces both metabolic and growth-promoting signals, and has transforming properties when overexpressed in the cells. Here we show that IRS-1 is translocated to the nucleus in the presence of the early viral protein-T-antigen of the human polyomavirus JC. Nuclear IRS-1 was detected in T-antigen-positive cell lines and in T-antigen-positive biopsies from patients diagnosed with medulloblastoma. The IRS-1 domain responsible for a direct JC virus T-antigen binding was localized within the N-terminal portion of IRS-1 molecule, and the binding was independent from IRS-1 tyrosine phosphorylation and was strongly inhibited by IRS-1 serine phosphorylation. In addition, competition for the IRS-1-T-antigen binding by a dominant negative mutant of IRS-1 inhibited growth and survival of JC virus T-antigen-transformed cells in anchorage-independent culture conditions. Based on these findings, we propose a novel role for the IRS-1-T-antigen complex in controlling cellular equilibrium during viral infection. It may involve uncoupling of IRS-1 from its surface receptor and translocation of its function to the nucleus.

Expression of JC virus T-antigen in a patient with MS and glioblastoma multiforme

OBJECTIVE

To investigate the presence of human polyomavirus JC virus genome and the expression of the viral oncoprotein T-antigen in neoplastic cells of a patient with MS and a glioblastoma multiforme.

BACKGROUND

The postmortem examination of an immunocompetent patient with a neurologic disorder revealed the concurrence of MS plaques in the white matter of the brain and a glioblastoma multiforme in the region of the thalamus.

METHODS AND RESULTS

PCR analysis of DNA from demyelinated plaques and the tumor area using primers derived from specific regions of the JC virus genome revealed the presence of viral DNA corresponding to the viral early and late genes. Further examination of the samples for the JC virus regulatory region identified the presence of sequences identical to JC virus Mad-4 and JC virus W1 viral isolates in the tumor and the demyelinated regions. Results from immunohistochemistry showed the detection of the viral early protein, T-antigen, and the cellular tumor suppressor protein, p53, in the nuclei of neoplastic cells. Interestingly, expression of T-antigen, but not p53, was observed in neurofilament-positive cells with neuronal morphology and in glial fibrillary acidic protein-positive astrocytes in the cortex juxtaposed to the MS plaques. Examination of viral late gene expression by immunohistochemistry showed no evidence for viral capsid proteins, thus ruling out productive replication of JC virus in the tumor and MS demyelinated plaques.

CONCLUSIONS

These observations provide molecular and clinical evidence of the association of JC virus in the brain of a patient with concurrent glioblastoma multiforme and MS.

Expression of human neurotropic polyomavirus JCV late gene product agnoprotein in human medulloblastoma

BACKGROUND

The human neurotropic polyomavirus, JCV, contains an open reading frame within the late region of the viral genome that encodes a 71-amino-acid protein, agnoprotein. Because accumulating evidence supports an association between JCV infection and human brain tumors, including medulloblastomas, we assessed the presence of JCV Agno gene sequences and the expression of agnoprotein in a series of 20 well-characterized medulloblastomas.

METHODS

Formalin-fixed, paraffin-embedded tumor tissue samples were used for Agno gene amplification and for immunohistochemical analysis. Adjacent sections were stained with an antibody to agnoprotein and with antibodies to cellular structural and regulatory proteins, including the JCV early gene product, T antigen.

RESULTS

Analysis of amplified DNA from paraffin-embedded samples revealed the presence of the Agno gene in 11 (69%) of 16 samples. Immunohistochemical analysis showed cytoplasmic localization and widespread distribution of agnoprotein in the neoplastic cells in 11 (55%) of 20 samples. The JCV early gene product, T antigen, was present in the nucleus of some, but not all, of the neoplastic cells. Some medulloblastoma samples that expressed agnoprotein had no sign of T-antigen expression. p53 was detected in only six of the 11 tumors in which agnoprotein was expressed. None of the 20 samples showed expression of the viral late capsid proteins, ruling out productive infection of the tumor cells with JCV.

CONCLUSIONS

Our data provide evidence that the JCV late gene encoding the auxiliary agnoprotein is expressed in tumor cells. The finding of agnoprotein expression in the absence of T-antigen expression suggests a potential role for agnoprotein in pathways involved in the development of JCV-associated medulloblastomas.

Detection of JC virus DNA sequences and expression of the viral regulatory protein T-antigen in tumors of the central nervous system

JC virus (JCV) is a neurotropic polyomavirus infecting greater than 70% of the human population worldwide during early childhood. Replication of JCV in brains of individuals with impaired immune systems results in the fatal demyelinating disease, progressive multifocal leukoencephalopathy (PML). Furthermore, JCV possesses an oncogenic potential and induces development of various neuroectodermal origin tumors including medulloblastomas and glioblastomas in experimental animals. The oncogenecity of JCV is attributed to the viral early gene product, T-antigen, which has the ability to associate with and functionally inactivate well-studied tumor suppressor proteins including p53 and pRB: The observations from laboratory animal experiments have provided a rationale for examining the presence of the JCV DNA sequence and expression of the viral oncogenic protein in human brain tumors. We have examined 85 clinical specimens from the United Kingdom, Greece, and the United States, representing various human brain tumors including oligodendroglioma, astrocytoma, pilocytic astrocytoma, oligoastrocytoma, anaplastic astrocytoma, anaplastic oligodendroglioma, glioblastoma multiforme, gliomatosis cerebri, gliosarcoma, ependymoma, and subependymoma, for their possible association with JCV. We performed gene amplification techniques using a pair of primers that recognize the JCV DNA sequence, and we demonstrated the presence of the viral early sequence in 49 (69%) of 71 samples. More importantly, our results from immunohistochemistry analysis revealed expression of JCV T-antigen in the nuclei of tumor cells in 28 (32.9%) of 85 tested samples. These observations, along with earlier in vitro and in vivo data on the transforming ability of this human neurotropic virus invite additional studies to re-evaluate the role of JCV in the pathogenesis of human brain tumors.

Cell cycle regulation of NF-kappa b-binding activity in cells from human glioblastomas

Glioblastoma multiforme is a highly malignant and anaplastic tumor of the central nervous system representing more than 50% of all malignant gliomas. The cell origin of this highly undifferentiated tumor remains obscure, although it is postulated that glioblastomas are developed from astrocytes. The rapid growth of the glioma and the state of its undifferentiation are attributed to the deregulation of several signal transduction pathways and cell cycle events. Recent studies showed diverse functions for the NF-kappa B/Rel family of inducible transcription factors including differentiation, apoptosis, oncogenesis, and cell cycle regulation. We sought to examine the level of NF-kappa B activity throughout the glioma's cell cycle. Results from band-shift studies indicated a biphasic NF-kappa B DNA-binding activity in the nuclei of cycling glioblastoma cells. We showed that NF-kappa B-binding activity maximizes in nuclear extracts at specific cell cycle stages including G0/G1, mid-late G1, and S phase. Results from Northern blotting studies revealed that the differential expression of the NF-kappa B subunits, p50 and p65, may not be responsible for cell cycle stage-specific association of NF-kappa B subunits with DNA. However, results from Western blotting analysis utilizing nuclear extracts from glioma cells throughout the cell cycle demonstrated that the nuclear accumulation of p50 and p65 perfectly correlates with their DNA-binding activity. These observations suggest that the nuclear translocation of the p50/p65 subunit of NF-kappa B in glioma cells is cell cycle stage-dependent and that is distinct from the differential mRNA expression of these genes during glioma cell cycling. The possible role of NF-kappa B in glioma cell formation and regulation of cellular genes by NF-kappa B in these tumor cells is discussed.

Reactivation of human neurotropic JC virus expressing oncogenic protein in a recurrent glioblastoma multiforme

Examination of the primary tumor of glioblastoma multiforme and its recurrence for their association with JC virus revealed that, while the viral genome is present in both initial and recurrent tumors, expression of the viral oncoprotein T-antigen occurs only in the recurrent tumor cells. Accordingly, the level of inducible cellular transcription factors, including the p65 subunit of NF-kappaB and YB-1, which have the ability to stimulate JCV gene expression, was found to be higher in the recurrent tumor cells. These observations suggest that induction of the regulatory factors after resection of the primary tumor may have reactivated JC virus gene expression and led to redevelopment of the tumor in brain.