Significant Association of Multiple Human Cytomegalovirus Genomic Loci with Glioblastoma Multiforme Samples

Institute for Molecular Virology, McArdle Laboratory for Cancer Research, Madison, Wisconsin, USA.
Journal of Virology (Impact Factor: 4.44). 11/2011; 86(2):854-64. DOI: 10.1128/JVI.06097-11
Source: PubMed


Viruses are appreciated as etiological agents of certain human tumors, but the number of different cancer types induced or exacerbated by viral infections is unknown. Glioblastoma multiforme (GBM)/astrocytoma grade IV is a malignant and lethal brain cancer of unknown origin. Over the past decade, several studies have searched for the presence of a prominent herpesvirus, human cytomegalovirus (HCMV), in GBM samples. While some have detected HCMV DNA, RNA, and proteins in GBM tissues, others have not. Therefore, any purported association of HCMV with GBM remains controversial. In most of the previous studies, only one or a select few viral targets were analyzed. Thus, it remains unclear the extent to which the entire viral genome was present when detected. Here we report the results of a survey of GBM specimens for as many as 20 different regions of the HCMV genome. Our findings indicate that multiple HCMV loci are statistically more likely to be found in GBM samples than in other brain tumors or epileptic brain specimens and that the viral genome was more often detected in frozen samples than in paraffin-embedded archival tissue samples. Finally, our experimental results indicate that cellular genomes substantially outnumber viral genomes in HCMV-positive GBM specimens, likely indicating that only a minority of the cells found in such samples harbor viral DNA. These data argue for the association of HCMV with GBM, defining the virus as oncoaccessory. Furthermore, they imply that, were HCMV to enhance the growth or survival of a tumor (i.e., if it is oncomodulatory), it would likely do so through mechanisms distinct from classic tumor viruses that express transforming viral oncoproteins in the overwhelming majority of tumor cells.

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    • "Meanwhile, the HCMV DNA and RNA have been detected in a subset of samples that have been assessed [1], [7], [13]. Noteworthy, when the HCMV DNA was investigated in a set of GBMs, only 1 out of 80 tumour cells was shown to carry the viral DNA [14]. "
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    ABSTRACT: Human cytomegalovirus (HCMV) has been indicated being a significant oncomodulator. Recent reports have suggested that an antiviral treatment alters the outcome of a glioblastoma. We analysed the performance of commercial HCMV-antibodies applying the immunohistochemical (IHC) methods on brain sample obtained from a subject with a verified HCMV infection, on samples obtained from 14 control subjects, and on a tissue microarray block containing cores of various brain tumours. Based on these trials, we selected the best performing antibody and analysed a cohort of 417 extra- and intra-axial brain tumours such as gliomas, medulloblastomas, primary diffuse large B-cell lymphomas, and meningiomas. HCMV protein pp65 immunoreactivity was observed in all types of tumours analysed, and the IHC expression did not depend on the patient's age, gender, tumour type, or grade. The labelling pattern observed in the tumours differed from the labelling pattern observed in the tissue with an active HCMV infection. The HCMV protein was expressed in up to 90% of all the tumours investigated. Our results are in accordance with previous reports regarding the HCMV protein expression in glioblastomas and medulloblastomas. In addition, the HCMV protein expression was seen in primary brain lymphomas, low-grade gliomas, and in meningiomas. Our results indicate that the HCMV protein pp65 expression is common in intra- and extra-axial brain tumours. Thus, the assessment of the HCMV expression in tumours of various origins and pathologically altered tissue in conditions such as inflammation, infection, and even degeneration should certainly be facilitated.
    Full-text · Article · Sep 2014 · PLoS ONE
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    • "To determine whether viral DNA was present in the tumor samples, frozen tumor tissue specimens were examined with PCR. DNA was amplified by PCR primers specific to the CMV UL123 open reading frame (forward 5′-CGACGTTCCTGCAGACTATG-3′ and reverse 5′-TCCTCGGTCACTTGTTCAAA-3′) [14]. The expected PCR product would be 117 bp. "
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    ABSTRACT: Human cytomegalovirus (CMV) has been detected in the thyroid gland and thyroid tumors. CMV infection may activate the mitogen-activated protein kinase pathway, of which aberrant activation is frequently associated with BRAF mutation in papillary thyroid cancer. A total of 45 paired tumorous and adjacent non-neoplastic tissue samples, including 5 follicular adenoma and 40 papillary thyroid cancer, were obtained during thyroidectomy. BRAF mutational status was determined using direct sequencing. The presence of CMV DNA was determined using conventional PCR and quantitative real-time PCR. CMV protein in the tissue samples were evaluated with Western blot analysis. BRAF mutation was identified in the cancerous part of 31 (78%) papillary thyroid cancers. Papillary cancer with BRAF mutation was significantly associated with a larger tumor size (P = 0.045), extrathyroidal invasion (P = 0.012), lymph node metastasis (P = 0.008), and a higher TNM stage (P = 0.044). CMV DNA and protein were not detected in any studied samples. Our results suggest no association between CMV infection and papillary thyroid cancer.
    Full-text · Article · Feb 2014 · World Journal of Surgical Oncology
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    • "Human cytomegalovirus (HCMV) is a member of the betaherpesvirus subfamily that has been found to be associated with several human malignancies, including glioblastoma [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17]. HCMV, like all other herpesviruses, has the ability to remain latent within the body for the lifetime of the host and can contribute to chronic inflammation, immunosuppression, and metabolic disruption of associated tissues. "
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    ABSTRACT: Glioblastoma multiforme (GBM) is a highly malignant primary central nervous system neoplasm characterized by tumor cell invasion, robust angiogenesis, and a mean survival of 15 months. Human cytomegalovirus (HCMV) infection is present in >90% of GBMs, although the role the virus plays in GBM pathogenesis is unclear. We report here that HCMV pp71, a viral protein previously shown to promote cell cycle progression, is present in a majority of human GBMs and is preferentially expressed in the CD133+, cancer stem-like cell population. Overexpression of pp71 in adult neural precursor cells resulted in potent induction of stem cell factor (SCF), an important pro-angiogenic factor in GBM. Using double immunofluorescence, we demonstrate in situ co-localization of pp71 and SCF in clinical GBM specimens. pp71 overexpression in both normal and transformed glial cells increased SCF secretion and this effect was specific, since siRNA mediated knockdown of pp71 or treatment with the antiviral drug cidofovir resulted in decreased expression and secretion of SCF by HCMV-infected cells. pp71- induced upregulation of SCF resulted in downstream activation of its putative endothelial cell receptor, c-kit, and angiogenesis as measured by increased capillary tube formation in vitro. We demonstrate that pp71 induces a pro-inflammatory response via activation of NFΚB signaling which drives SCF expression. Furthermore, we show that pp71 levels and NFKB activation are selectively augmented in the mesenchymal subtype of human GBMs, characterized by worst patient outcome, suggesting that HCMV pp71-induced paracrine signaling may contribute to the aggressive phenotype of this human malignancy.
    Full-text · Article · Jul 2013 · PLoS ONE
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