scholarly journals Pathogenic Role of Immune Evasion and Integration of Human Papillomavirus in Oropharyngeal Cancer

2021 ◽  
Vol 9 (5) ◽  
pp. 891
Author(s):  
Takashi Hatano ◽  
Daisuke Sano ◽  
Hideaki Takahashi ◽  
Nobuhiko Oridate

The incidence of oropharyngeal cancer (OPC) is increasing remarkably among all head and neck cancers, mainly due to its association with the human papillomavirus (HPV). Most HPVs are eliminated by the host’s immune system; however, because HPV has developed an effective immune evasion mechanism to complete its replication cycle, a small number of HPVs are not eliminated, leading to persistent infection. Moreover, during the oncogenic process, the extrachromosomal HPV genome often becomes integrated into the host genome. Integration involves the induction and high expression of E6 and E7, leading to cell cycle activation and increased genomic instability in the host. Therefore, integration is an important event in oncogenesis, although the associated mechanism remains unclear, especially in HPV-OPC. In this review, we summarize the current knowledge on HPV-mediated carcinogenesis, with special emphasis on immune evasion and integration mechanisms, which are crucial for oncogenesis.

2006 ◽  
Vol 24 (36) ◽  
pp. 5630-5636 ◽  
Author(s):  
Lisa Licitra ◽  
Federica Perrone ◽  
Paolo Bossi ◽  
Simona Suardi ◽  
Luigi Mariani ◽  
...  

Purpose Human papillomavirus (HPV) DNA tumors actively integrating the E6 and E7 oncogenes have a distinct biologic behavior resulting in a more favorable prognosis. To which extent the viral integration by itself, and/or the associated wild-type (wt) TP53 status, and/or a functional p16 contribute to prognosis is unclear. Patients and Methods To clarify how the presence of high-risk (HR) -HPV, TP53, and p16INK4a status interact with clinical outcome, we considered a retrospective series of 90 consecutive oropharyngeal cancer patients treated primarily with surgery. Results Seventeen (19%) patients showed integrated HPV 16 DNA (HPV positive), wt TP53 in all but two patients, normal p16INK4a in 15 assessable patients, and p16 expression in all 17 patients. Thirty-five patients (39%), two of whom were HPV positive, harbored TP53 mutations. p16INK4a deletion and p16 null immunophenotype occurred in 28 and 58 patients, respectively, and was similarly distributed in both patients with mutated TP53 (48% and 82%, respectively) and in patients with wt TP53 (46% and 77%, respectively). Statistical analysis showed that HPV-positive status significantly affects all investigated end points: overall survival (P = .0018), incidence of tumor relapse (P = .0371), and second tumor (P = .0152), whereas TP53 and p16INK4a status and p16 expression were not prognostic by themselves. Conclusion Our molecular and clinical results are in agreement with previous findings but provide additional information into the biologic mechanisms involved in HR-HPV oropharyngeal cancer in comparison to HPV-negative tumors. According to the reduced risk of relapse and second tumors associated with HR-HPV positivity of oropharyngeal cancer, the therapeutic strategy and follow-up procedures should be reviewed.


Head & Neck ◽  
2019 ◽  
Vol 41 (6) ◽  
pp. 1756-1769 ◽  
Author(s):  
Alexander N. Goel ◽  
Mariana Frangos ◽  
Govind Raghavan ◽  
Sophia Sangar ◽  
Stephanie Lazaro ◽  
...  

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Masahiko Ajiro ◽  
Zhi-Ming Zheng

ABSTRACTTranscripts of human papillomavirus 16 (HPV16) E6 and E7 oncogenes undergo alternative RNA splicing to produce multiple splice isoforms. However, the importance of these splice isoforms is poorly understood. Here we report a critical role of E6^E7, a novel isoform containing the 41 N-terminal amino acid (aa) residues of E6 and the 38 C-terminal aa residues of E7, in the regulation of E6 and E7 stability. Through mass spectrometric analysis, we identified that HSP90 and GRP78, which are frequently upregulated in cervical cancer tissues, are two E6^E7-interacting proteins responsible for the stability and function of E6^E7, E6, and E7. Although GRP78 and HSP90 do not bind each other, GRP78, but not HSP90, interacts with E6 and E7. E6^E7 protein, in addition to self-binding, interacts with E6 and E7 in the presence of GRP78 and HSP90, leading to the stabilization of E6 and E7 by prolonging the half-life of each protein. Knocking down E6^E7 expression in HPV16-positive CaSki cells by a splice junction-specific small interfering RNA (siRNA) destabilizes E6 and E7 and prevents cell growth. The same is true for the cells with a GRP78 knockdown or in the presence of an HSP90 inhibitor. Moreover, mapping and alignment analyses for splicing elements in 36 alpha-HPVs (α-HPVs) suggest the possible expression of E6^E7 mostly by other oncogenic or possibly oncogenic α-HPVs (HPV18, -30, -31, -39, -42, -45, -56, -59, -70, and -73). HPV18 E6^E7 is detectable in HPV18-positive HeLa cells and HPV18-infected raft tissues. All together, our data indicate that viral E6^E7 and cellular GRP78 or HSP90 might be novel targets for cervical cancer therapy.IMPORTANCEHPV16 is the most prevalent HPV genotype, being responsible for 60% of invasive cervical cancer cases worldwide. What makes HPV16 so potent in the development of cervical cancer remains a mystery. We discovered in this study that, besides producing two well-known oncoproteins, E6 and E7, seen in other high-risk HPVs, HPV16 produces E6^E7, a novel splice isoform of E6 and E7. E6^E7, in addition to self-interacting, binds cellular chaperone proteins, HSP90 and GRP78, and viral E6 and E7 to increase the steady-state levels and half-lives of viral oncoproteins, leading to cell proliferation. The splicingciselements in the regulation of HPV16 E6^E7 production are highly conserved in 11 oncogenic or possibly oncogenic HPVs, and we confirmed the production of HPV18 E6^E7 in HPV18-infected cells. This study provides new insight into the mechanism of splicing, the interplay between different products of the polycistronic viral message, and the role of the host chaperones as they function.


Author(s):  
Nandini Eswaran ◽  
Shwetha Krishna

Background: The emergence and the spread of the novel coronavirus or the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a devastating impact on the economy and has become a pressing issue globally. Due to the significant increase in the number of confirmed cases and death tolls worldwide, and certain countries reporting second waves, there is an immediate need for an effective vaccine or other therapeutic intervention to control the spread of the disease. Improving our understanding on the host’s anti-viral immune response on SARS-CoV-2 infection, the potential immune evasion mechanisms adopted by the virus, and the speculated role of antibody dependent enhancement (ADE) in coronavirus disease 2019 (COVID-19) pathogenesis will aid in identifying and designing effective therapeutics. Aim: This review aims to provide an in-depth view of the current knowledge available on the range of host defense mechanisms activated by SARS-CoV-2 infection and various immune evasion mechanisms utilized by the virus. In addition, it also highlights the postulated role of ADE in viral pathogenesis and covers the different preventive and therapeutic options available for the treatment of COVID-19 based on current literature. Discussion: The ongoing COVID-19 pandemic serves as a timely reminder on the constant evolutionary process the virus undergoes to emerge as a novel strain and to spread undetected within the population. Similar to other infectious diseases, the host defence mechanism is triggered, and it plays a central role in dampening viral replication by recruiting immune cells and activating anti-viral mechanisms to control the spread of infection by SARS-CoV-2. However, the virus has adopted different immune evasion mechanisms to circumvent host surveillance to successfully establish infection. Hence, understanding the host’s immune responses triggered by SARS-CoV-2 infection is critical for identifying and designing novel and effective therapeutics. Currently, over 70% of the population are either asymptomatic or they showcase mild to moderate symptoms and reasons for why some people can mount immune responses more quickly than others are unknown. However, a growing body of research speculates that the ADE mechanism may facilitate the SARS-CoV-2 entry and can contribute to severe clinical manifestations. With the constant rise in the number of confirmed cases, there is an immediate need for an effective vaccine to mitigate the spread of the virus. Presently, there is no treatment for COVID-19 although several vaccine candidates are in clinical trials. Therefore, preventive measures like social distancing, isolation, and travel restrictions, may be the key to controlling the rapid spread of COVID-19.


2016 ◽  
Vol 4 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Karl Bonello ◽  
Renald Blundell

The human papillomavirus (HPV) was the first virus known to induce carcinogenesis and is associated with cancers of the uterine cervix, anogenital tumors and malignancies of the head and neck. This paper reviews the structure and basic genomic characteristics of the virus and outlines the clinical involvement of the main HPV serotypes, focusing on the carcinogenic role of HPV-16 and 18. The mechanisms that occur in the development of cervical neoplasia due to the oncogenic proteins E6 and E7 which interfere with the regulation of the cell cycle through their interaction with p53 and retinoblastoma protein are described. Epidemiological factors, diagnostic tools and the management of the disease are also reviewed, along with the available vaccines to prevent the viral infection. Insights on current research on involvement of oxidative stress and micro-RNAs in cervical carcinogenesis are also explored as they may unlock new means of diagnosis and treatment in the future.


2018 ◽  
Vol 17 (5) ◽  
pp. 100-105
Author(s):  
A. M. Mudunov

Squamous cell carcinoma of the head and neck organs occupies the 5th place in the structure of oncological morbidity in the world. The mortality from this pathology has not changed for several decades, despite significant successes and achievements in modern clinical oncology. In article are explored and analyzed: the etiological role of human papillomavirus (HPV) in the development of oropharyngeal cancer; sexual and age specific features of HPV-associated cancer, various methods of predictive diagnosis, specific prevention. Conclusions: papillomavirus infection is the main cause of the sharp and continuing increase in the incidence of oropharyngeal cancer, mainly among men in many countries of the world; vaccination has positive expectations in the prevention of the incidence of oropharyngeal cancer.


2002 ◽  
Vol 188 (1-2) ◽  
pp. 15-24 ◽  
Author(s):  
Patrick Finzer ◽  
Adriana Aguilar-Lemarroy ◽  
Frank Rösl

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 289 ◽  
Author(s):  
Surendra Sharma ◽  
Karl Munger

Infections with high-risk human papillomaviruses cause ~5% of all human cancers. E6 and E7 are the only viral genes that are consistently expressed in cancers, and they are necessary for tumor initiation, progression, and maintenance. E6 and E7 encode small proteins that lack intrinsic enzymatic activities and they function by binding to cellular regulatory molecules, thereby subverting normal cellular homeostasis. Much effort has focused on identifying protein targets of the E6 and E7 proteins, but it has been estimated that ~98% of the human transcriptome does not encode proteins. There is a growing interest in studying noncoding RNAs as biochemical targets and biological mediators of human papillomavirus (HPV) E6/E7 oncogenic activities. This review focuses on HPV E6/E7 targeting cellular long noncoding RNAs, a class of biologically versatile molecules that regulate almost every known biological process and how this may contribute to viral oncogenesis.


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