The role of Microenvironment in tumorigenesis. Focus on dendritic cells in human papillomavirus E6, E7-transformed keratinocytes

The inception of tumor microenvironment (TME), a complex and dynamic system constituted by different types of cells engaged by tumor and extracellular matrix surrounding cancer cells, is a way for them to elude the immune surveillance. Dendritic cells (DCs), as a sentinel, are able to recognize alteration in the microenvironment and predispose the immune system response. The relationship between cancer and virus infection is well documented. High-risk Human Papillomavirus (HR-HPV) has a well-characterized transforming property and has been associated with squamous cell carcinoma of the ano-genital and oral tracts. Transforming ability of HR-HPVs is based on the function of E6 and E7 viral oncoproteins, which interact and inactivate p53 and pRb oncosuppressors, respectively. Recently, it was demonstrated that HPV oncoproteins are also able to affect a number of microRNAs (miRNAs) regulating the expression of genes involved in proliferative control. For these reasons DC-based vaccines targeting oncogenic E6 and E7 are ideal candidates to elicit strong immune responses. Here we summarize significant data about the analysis of TME in HPV-induced tumorigenesis. We also report original results produced by cytotoxic T lymphocyte (CTL) in vitro priming against E6 and E7 HPV16 antigens, performed using human monocyte-derived dendritic cells. Dendritic cells, maturated by the exposition to necrotic or apoptotic keratinocytes expressing both oncoproteins of HPV16, show different expression levels of specific maturation markers. Evidence indicating the ability of necrotic keratinocytes to alter the microRNA profile in DCs, macrophages (MΦ) and Langerhans cells (LCs) compared to prototypical stimuli as bacterial lipopolysaccharide was also provided. We can speculate that, based on transformed cells death pathway (i.e. apoptosis versus necrosis), virus-induced immune alterations might show different results in creating an immunotolerogenic microenvironment during the carcinogenesis process

Role of Extracellular Vesicles in Human Papillomavirus-Induced Tumorigenesis

Emerging evidence demonstrates a role of extracellular vesicles (EVs) in a variety of fundamental physiological and pathological processes ranging from antigen presentation to T cell to neurodegenerative diseases. In several types of malignancies, a variety of EVs can be isolated from bodily fluids of cancer patients, and it has been reported that the number of circulating EVs seems to be higher than in healthy subjects. This increase correlates with poor prognosis. Data obtained from different groups clearly point out a role of EVs in the transfer of bioactive molecules such as microRNAs and viral oncoproteins in human papillomavirus-induced malignancies of genital and oral tracts. This study summarizes these data in the context of relevant literature considering the EVs as carriers of oncogenic signatures in human cancer as well as their therapeutic potential in HPV-related tumors

MicroRNAs differentially expressed in actinic keratosis and healthy skin scrapings

: Actinic keratosis (AK) is a carcinoma in situ precursor of cutaneous squamous cell carcinoma (cSCC), the second most common cancer affecting the Caucasian population. AK is frequently present in the sun-exposed skin of the elderly population, UV radiation being the main cause of this cancer, and other risk factors contributing to AK incidence. The dysregulation of microRNAs (miRNAs) observed in different cancers leads to an improper expression of miRNA targets involved in several cellular pathways. The TaqMan Array Human MicroRNA Card assay for miRNA expression profiling was performed in pooled AK compared to healthy skin scraping samples from the same patients. Forty-three miRNAs were modulated in the AK samples. The expression of miR-19b (p < 0.05), -31, -34a (p < 0.001), -126, -146a (p < 0.01), -193b, and -222 (p < 0.05) was validated by RT-qPCR. The MirPath tool was used for MiRNA target prediction and enriched pathways. The top DIANA-mirPath pathways regulated by the targets of the 43 miRNAs are TGF-beta signaling, Proteoglycans in cancer, Pathways in cancer, and Adherens junction (7.30 × 10-10 < p < 1.84 × 10-8). Selected genes regulating the KEGG pathways, i.e., TP53, MDM2, CDKN1A, CDK6, and CCND1, were analyzed. MiRNAs modulated in AK regulate different pathways involved in tumorigenesis, indicating miRNA regulation as a critical step in keratinocyte cancer

Detection of human papillomaviruses in paired healthy skin and actinic keratosis by next generation sequencing

peer reviewe

Targeting Human Papillomavirus-Associated Cancer by Oncoprotein-Specific Recombinant Antibodies

In recent decades, recombinant antibodies against specific antigens have shown great promise for the therapy of infectious diseases and cancer. Human papillomaviruses (HPVs) are involved in the development of around 5% of all human cancers and HPV16 is the high-risk genotype with the highest prevalence worldwide, playing a dominant role in all HPV-associated cancers. Here, we describe the main biological activities of the HPV16 E6, E7, and E5 oncoproteins, which are involved in the subversion of important regulatory pathways directly associated with all known hallmarks of cancer. We then review the state of art of the recombinant antibodies targeted to HPV oncoproteins developed so far in different formats, and outline their mechanisms of action. We describe the advantages of a possible antibody-based therapy against the HPV-associated lesions and discuss the critical issue of delivery to tumour cells, which must be addressed in order to achieve the desired translation of the antibodies from the laboratory to the clinic

Monocyte-Derived dendritic cells are able to induce an E6/E7- specific, HLA I-restricted, cytotoxic actvity

The adoptive transfer of cancer Ag-specific effector T cells in patients can result in tumor rejection, thereby illustrating the immune system potential for cancer therapy. For this point of view, viruses involved in tumorigenesis are useful targets because viral proteins are not expressed in normal cells and, generally, their expression is required to maintain the malignant phenotype. Between oncoviruses, human papillomavirus (HPV) has a well-characterized transforming propriety and it has been associated with squamous cell carcinoma of the ano-genital and oral tracts. In addition cutaneous genotypes are also associated with some forms of non-melanoma skin cancer. Transforming ability of HPV is based on the function of E6 and E7 viral oncoproteins, which interact and inactivate pRB and p53 oncosuppressors, respectively. For these reasons vaccines targeting oncogenic E6 and E7 are ideal candidates to elicit strong immune responses without generating autoimmunity. Here we report preliminary results obtained using a protocol based on human monocyte-derived dendritic cells (MDDC) incubated in vitro with apoptotic keratinocytes expressing both E6 and E7 oncoproteins derived from mucosal (HPV16) or cutaneous (HPV38) genotypes. We observed the capability of MDDCs i) to uptake apoptotic bodies from transformed keratinocytes; ii) to upregulate the expression of class I HLA and CD86 co-stimulatory molecule following apoptotic bodies uptake and iii) to specifically prime in vitro cytotoxic T lymphocytes against E6/E7-expressing keratinocytes. These findings indicate that this strategy could be a feasible immunotherapeutic approach for the treatment of established viral-induced tumors helping to launch more effective and less invasive therapeutic vaccines for HPV-mediated malignancies

Monocyte-Derived dendritic cells are able to induce an E6/E7- specific, HLA I-restricted, cytotoxic activity

The adoptive transfer of cancer Ag-specific effector T cells in patients can result in tumor rejection, thereby illustrating the immune system potential for cancer therapy. For this point of view, viruses involved in tumorigenesis are useful targets because viral proteins are not expressed in normal cells and, generally, their expression is required to maintain the malignant phenotype. Between oncoviruses, human papillomavirus (HPV) has a well-characterized transforming propriety and it has been associated with squamous cell carcinoma of the ano-genital and oral tracts. In addition cutaneous genotypes are also associated with some forms of non-melanoma skin cancer. Transforming ability of HPV is based on the function of E6 and E7 viral oncoproteins, which interact and inactivate pRB and p53 oncosuppressors, respectively. For these reasons vaccines targeting oncogenic E6 and E7 are ideal candidates to elicit strong immune responses without generating autoimmunity. Here we report preliminary results obtained using a protocol based on human monocyte-derived dendritic cells (MDDC) incubated in vitro with apoptotic keratinocytes expressing both E6 and E7 oncoproteins derived from mucosal (HPV16) or cutaneous (HPV38) genotypes. We observed the capability of MDDCs i) to uptake apoptotic bodies from transformed keratinocytes; ii) to upregulate the expression of class I HLA and CD86 co-stimulatory molecule following apoptotic bodies uptake and iii) to specifically prime in vitro cytotoxic T lymphocytes against E6/E7-expressing keratinocytes. These findings indicate that this strategy could be a feasible immunotherapeutic approach for the treatment of established viral-induced tumors helping to launch more effective and less invasive therapeutic vaccines for HPV-mediated malignancies

Inflammatory microenvironment and human papillomavirus-induced carcinogenesis

More than 15% of the global cancer burden is attributable to infectious agents. Pathogens that cause persistent infections are strongly associated with cancer, inflammation being a major component of the chronic infections as revealed by basic, clinical and epidemiological studies. Persistent infection and viral oncoproteins induce specific cellular pathways modifications that promote tumorigenesis. Deregulated and continuous immune response leads to severe tissue and systemic damage, impaired tumor surveillance and consequent carcinogenesis promotion by selecting for metastatic and therapeutically resistant tumor phenotypes. In this review, the role of inflammatory microenvironment in the HPV-induced carcinogenesis is addressed, with a specific focus on the involvement of the immune molecules and microRNAs as well as their delivery through the microvesicle cargo