Previous studies have established that a subset of head and neck tumors contains human papillomavirus (HPV) sequences and that HPV-driven head and neck cancers display distinct biological and clinical features. HPV is known to drive cancer by the actions of the E6 and E7 oncoproteins, but the molecular architecture of HPV infection and its interaction with the host genome in head and neck cancers have not been comprehensively described. We profiled a cohort of 279 head and neck cancers with next generation RNA and DNA sequencing and show that 35 (12.5%) tumors displayed evidence of high-risk HPV types 16, 33, or 35. Twentyfive cases had integration of the viral genome into one or more locations in the human genome with statistical enrichment for genic regions. Integrations had a marked impact on the human genome and were associated with alterations in DNA copy number, mRNA transcript abundance and splicing, and both inter-and intrachromosomal rearrangements. Many of these events involved genes with documented roles in cancer. Cancers with integrated vs. nonintegrated HPV displayed different patterns of DNA methylation and both human and viral gene expressions. Together, these data provide insight into the mechanisms by which HPV interacts with the human genome beyond expression of viral oncoproteins and suggest that specific integration events are an integral component of viral oncogenesis.cancer | head and neck | papilloma virus | genome rearrangement | integration sites H ead and neck cancer (HNC) is a heterogeneous group of tumors characterized by a common anatomic origin, and most such tumors develop from within the mucosa and are classified as head and neck squamous cell carcinomas (HNSCCs) (1). HNSCC, the sixth most common cancer diagnosed worldwide and the eighth most common cause of cancer death (2), is frequently associated with human papillomavirus (HPV) infection (3, 4). Depending on the anatomic site of the tumor, HPV prevalence is estimated at 23-36% (5). HPV-positive HNSCCs form a distinct subset of HNCs that differs from HPV-negative HNSCCs in tumor biology and clinical characteristics, including superior clinical outcomes (6-9).The molecular pathogenesis of HPV-driven HNSCC also seems distinct from HPV-negative tumors, with previous studies showing a divergent spectrum of alterations in gene expression, mutations, amplifications, and deletions as well as distinct epigenome alterations (10-15). HPV is known to drive tumorigenesis through the actions of its major oncoproteins E6 and E7, which target numerous cellular pathways, including inactivation of p53 and the retinoblastoma (Rb) protein (16-18). Together with E5, they also play an important role in immune evasion, being involved in both innate and adaptive immunity (19,20).Initially after infection, HPV is identified in circular extrachromosomal particles or episomes. A critical step in progression to cancer is the integration of viral DNA into the host cell Significance A significant proportion of head and neck cancer is driven by human papil...
Nasopharyngeal carcinoma (NPC) is a unique epithelial malignancy arising from the superior aspect of the pharyngeal mucosal space, associated with latent Epstein-Barr virus infection in most cases. The capacity to characterize cancer genomes in unprecedented detail is now providing insights into the genesis and molecular underpinnings of this disease. Herein, we provide an overview of the molecular aberrations that likely drive nasopharyngeal tumor development and progression. The contributions of major Epstein-Barr virus-encoded factors, including proteins, small RNAs, and microRNAs, along with their interactions with pathways regulating cell proliferation and survival are highlighted. We review recent analyses that clearly define the role of genetic and epigenetic variations affecting the human genome in NPC. These findings point to the impact of DNA methylation and histone modifications on gene expression programs that promote this malignancy. The molecular interactions that allow NPC cells to evade immune recognition and elimination, which is crucial for the survival of cells expressing potentially immunogenic viral proteins, are also described. Finally, the potential utility of detecting host and viral factors for the diagnosis and prognosis of NPC is discussed. Altogether, the studies summarized herein have greatly expanded our knowledge of the molecular biology of NPC, yet much remains to be uncovered. Emerging techniques for using and analyzing well-annotated biospecimens from patients with NPC will ultimately lead to a greater level of understanding, and enable improvements in precision therapies and clinical outcomes.
Head and neck cancers (HNCs) are a highly heterogeneous group of tumours that are associated with diverse clinical outcomes. Recent evidence has demonstrated that human papillomavirus (HPV) is involved in up to 25% of HNCs; particularly in the oropharyngeal carcinoma (OPC) subtype where it can account for up to 60% of such cases. HPVs are double-stranded DNA viruses that infect epithelial cells; numerous HPV subtypes, including 16, 18, 31, 33, and 35, drive epithelial cell transformation and tumourigenesis. HPV positive (HPV+) HNC represents a distinct molecular and clinical entity from HPV negative (HPV−) disease; the biological basis for which remains to be fully elucidated. HPV positivity is strongly correlated with a significantly superior outcome; indicating that such tumours should have a distinct management approach. This review focuses on the recent scientific and clinical investigation of HPV+ HNC. In particular, we discuss the importance of molecular and clinical evidence for defining the role of HPV in HNC, and the clinical impact of HPV status as a biomarker for HNC.
Purpose: Deregulation of miRNAs is associated with almost all human malignancies. Human papillomavirus (HPV)-associated oropharyngeal carcinoma (OPC) has a significantly more favorable outcome compared with HPV-negative OPCs; however, the underlying mechanisms are not well understood. Hence, the objectives of this study were to determine whether miRNA expression differed as a function of HPV status and to assess whether such miRNAs provide prognostic value beyond HPV status.Methods: Global miRNA profilings were conducted on 88 formalin-fixed and paraffin-embedded (FFPE) OPC biopsies (p16-positive: 56; p16-negative: 32), wherein the expression levels of 365 miRNAs plus 3 endogenous controls were simultaneously measured using quantitative real-time (qRT)-PCR. Seven FFPE specimens of histologically normal tonsils were used as controls.Results: Overall, 224 miRNAs were expressed in more than 80% of the investigated samples, with 128 (57%) being significantly differentially expressed between tumor versus normal tissues (P < 0.05). Upregulated miR-20b, miR-9, and miR-9 Ã were significantly associated with HPV/p16-status. Three miRNA sets were significantly associated with overall survival (miR-107, miR-151, miR-492; P ¼ 0.0002), diseasefree survival (miR-20b, miR-107, miR-151, miR-182, miR-361; P ¼ 0.0001), and distant metastasis (miR-151, miR-152, miR-324-5p, miR-361, miR492; P ¼ 0.0087), which retained significance even after adjusting for p16 status. The associated biologic functions of these miRNAs include immune surveillance, treatment resistance, invasion, and metastasis. Conclusion: We have identified several miRNAs, which associate with HPV status in OPC; furthermore, three candidate prognostic sets of miRNAs seem to correlate with clinical outcome, independent of p16 status. Furthermore, evaluations will offer biologic insights into the mechanisms underlying the differences between HPV-positive versus HPV-negative OPC.
Exosomes and microvesicles (MVs) are nanometer-sized, membranous vesicles secreted from many cell types into their surrounding extracellular space and into body fluids. These two classes of extracellular vesicles are regarded as a novel mechanism through which cancer cells, including virally infected cancer cells, regulate their micro-environment via the horizontal transfer of bioactive molecules: proteins, lipids, and nucleic acids (DNA, mRNA, micro-RNAs; oncogenic cargo hence often referred to as oncosomes). In head and neck cancer (HNC), exosomes and MVs have been described in Epstein Barr Virus (EBV)-associated nasopharyngeal cancer (NPC), as well as being positively correlated with oral squamous cell carcinoma (OSCC) progression. It has therefore been suggested that HNC-derived vesicles could represent a useful source for biomarker discovery, enriched in tumor antigens and cargo; hence fundamentally important for cancer progression. This current review offers an overall perspective on the roles of exosomes and MVs in HNC biology, focusing on EBV-associated NPC and OSCC. We also highlight the importance of saliva as a proximal and easily accessible bio-fluid for HNC detection, and propose that salivary vesicles might serve as an alternative model in the discovery of novel HNC biomarkers.
Cervical cancer is the third most common cancer in women worldwide. In the present study, global microRNA profiling for 79 cervical cancer patient samples led to the identification of miR-218 down-regulation in cervical cancer tissues compared to normal cervical tissues. Lower miR-218 expression was associated significantly with worse overall survival (OS), disease-free survival (DFS), and pelvic/aortic lymph node recurrence. In vitro, miR-218 over-expression decreased clonogenicity, migration, and invasion. Survivin (BIRC5) was subsequently identified as an important cervical cancer target of miR-218 using in silico prediction, mRNA profiling, and quantitative real-time PCR (qRT-PCR). Concordant with miR-218 over-expression, survivin knockdown by siRNA decreased clonogenicity, migration, and invasion. YM155, a small molecule survivin inhibitor, significantly suppressed tumor growth and lymph node metastasis in vivo. Our findings demonstrate that the miR-218~survivin axis inhibits cervical cancer progression by regulating clonogenicity, migration, and invasion, and suggest that the inhibition of survivin could be a potential therapeutic strategy to improve outcome in this disease.
Head and neck squamous cell carcinoma (HNSCC) is a highly heterogeneous disease that develops via one of the two primary carcinogenic routes: chemical carcinogenesis through exposure to tobacco and alcohol or virally induced tumorigenesis. Human papillomavirus (HPV)-positive (HPV þ ) and HPV-negative (HPV À ) HNSCCs represent distinct clinical entities, with the latter associated with significantly inferior outcome. The biologic basis of these different outcomes is an area of intense investigation; their therapeutic regimens are currently also being reevaluated, which would be significantly facilitated by reliable biomarkers for stratification. With the advent of the omics era and accelerated development of targeted therapies, there are unprecedented opportunities to address the challenges in the management of HNSCC. As summarized herein, side-by-side molecular characterization of HPV þ versus HPV À HNSCC has revealed distinct molecular landscapes, novel prognostic signatures, and potentially targetable biologic pathways. In particular, we focus on the evidence acquired from genome-wide omics pertinent to our understanding of the clinical behavior of HNSCC and on insights into personalized treatment opportunities. Integrating, mining, and validating these data toward clinically meaningful outcomes for patients with HNSCC in conjunction with systematic verification of the functional relevance of these findings are critical steps toward the design of personalized therapies. Cancer Res; 75(3); 480-6. Ó2014 AACR. Oncogenic Role of Human PapillomavirusesHigh-risk human papillomaviruses (HPV) are double-stranded DNA viruses that infect epithelial cells (1). Tumorigenesis by high-risk HPVs is driven by their two main viral oncogenes, E6 and E7, which inactivate p53 and pRb, respectively, leading to cellcycle deregulation and inhibition of p53-mediated apoptosis (1, 2). E7 binds pRb, targeting it toward proteosomal degradation, in turn releasing the E2F transcription factor, resulting in CDKN2A (or p16) overexpression and cell-cycle progression (1).High-risk HPVs, predominantly types 16, 18, 31, 33, and 35, are estimated to cause approximately 5% of cancers worldwide, including 99% of cervical, 25% of head and neck (or 60% oropharyngeal), 70% of vaginal, 88% of anal, 43% of vulvar, and 50% of penile cancers, in order of prevalence (1-6). A significant subset of approximately 500,000 annual cases of head and neck squamous cell carcinoma (HNSCC) include approximately 85,000 HPV-associated tumors, establishing this as the second most common HPV-associated tumor site (3, 4). HPV type 16 is identified in over 90% of HPV-associated HNSCCs (4). The majority of the remaining HNSCCs are attributed to exposure to chemical carcinogens such as tobacco and alcohol.HPV-positive (HPV þ ) and HPV-negative (HPV À ) HNSCCs are separate entities associated with distinct etiology, clinical behavior, treatment outcomes, imaging and pathology appearance, and molecular profiles (2, 7). HPV þ HNSCC primarily involves the oropharynx (pr...
Purpose: Despite recent improvements in local control of head and neck cancers (HNC), distant metastasis remains a major cause of death. Hence, further understanding of HNC biology, and in particular, the genes/pathways driving metastasis is essential to improve outcome.Experimental Design: Quantitative reverse transcriptase PCR (qRT-PCR) was used to measure the expression of miR-375 and metadherin (MTDH) in HNC patient samples. Targets of miR-375 were confirmed using qRT-PCR, Western blot analysis, and luciferase assays. Phenotypic effects of miR-375 reexpression and MTDH knockdown were assessed using viability (MTS), clonogenic survival, cell migration/invasion, as well as in vivo tumor formation assays. The prognostic significance of miR-375 or MTDH in nasopharyngeal carcinoma (NPC) was determined by comparing low versus high expression groups.Results: MiR-375 expression was significantly reduced (P ¼ 0.01), and conversely, MTDH was significantly increased (P ¼ 0.0001) in NPC samples. qRT-PCR, Western blots, and luciferase assays corroborated MTDH as a target of miR-375. Reexpression of miR-375 and siRNA knockdown of MTDH both decreased cell viability and clonogenic survival, cell migration/invasion, as well as in vivo tumor formation. NPC patients whose tumors expressed high levels of MTDH experienced significantly lower survival and, in particular, higher distant relapse rates (5-year distant relapse rates: 26% vs. 5%; P ¼ 0.005).Conclusions: Dysregulation of miR-375 and MTDH may represent an important oncogenic pathway driving human HNC progression, particularly distant metastases, which is now emerging as a major cause of death for HNC patients. Hence, targeting this pathway could potentially be a novel therapeutic strategy by which HNC patient outcome could be improved. Clin Cancer Res; 17(24); 7539-50. Ó2011 AACR.
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