Aldo Venuti

Human papillomavirus in breast cancer

SummaryHistological sections from paraffin-embedded breast carcinoma and axillary lymph nodes were examined for the presence of human papillomaviruses by two different techniques: the polymerase chain reaction (PCR) and thein situ hybridization with biotin-labelled probes. By PCR we detected HPV 16 DNA sequences in 29.4% of breast tumours and in some metastatic lymph nodes, though we were unable to identify any HPV DNA sequences byin situ hybridization. These results suggest that HPVs could play a role in the genesis of breast neoplasia.

HPV detection methods in head and neck cancer.

Human papillomavirus (HPV) infection is emerging as a major prognostic and predictive marker in head and neck squamous cell carcinoma (HNSCC). Researches are focused on the development of HPV detection assays specially designed for HNSCC. The HPV diagnosis in these tumours is relevant toprognosis even in an already-developed tumour, whereas in the cervix, where the HPV is the cause of almost all tumours, this information has less clinical relevance. The better outcome of HPV-associated HNSCC raises the question about the best methodologies to distinguish between HPV and non-HPV-associated SCC. However, no consensus has been reached on the optimal way to identify HPV-associated SCC and ancillary studies have utilised many different methodologies, including HPV polymerase chain reaction testing, HPV in situ hybridization analysis, immunohistochemical staining for p16, and newer techniques that are currently under investigation. The objective of this review is to explain and give examples of various techniques of HPV detection highlighting how they might be used clinically. Although currently insufficiently specific due to the possibility of HPV infection originating at other sites, methodologies utilising serum and plasma to measure HPV infection will also be described, mostly for their potential future development and use. Finally, DNA/RNA microarray platforms will be briefly summarized for their capacity to identify the profile of molecular changes in any particular HPV+/HPV− cancer. In this way, it is expected to be possible to correlate the appropriate transcriptome-based diagnosis to the patients’ specific cancer risk.

Physical state and expression of human papillomavirus in laryngeal carcinoma and surrounding normal mucosa.

Epidemiologic and biomolecular evidence suggests that human papillomavirus (HPV) infection may be associated with the development of head and neck cancers. To clarify the role of HPV in larynx carcinoma, 25 patients were studied for the presence of viral DNA, possible virus integration into the cellular genome, and viral expression both in neoplastic tissues and in neighbouring normal mucosa. Twelve of 25 patients with neoplasia (48%) showed negative results for HPV sequences, and 13 (52%) showed positive results. Among the latter group of patients, seven were HPV‐16 positive, five were HPV‐6, and one was HPV‐45. No multiple infections were detected. The physical status of the HPV genome was analysed by three methods: polymerase chain reaction (PCR), bidimensional agarose gel electrophoresis, and in situ hybridisation. Viral integration into the host genome occurred in 43% of cases of HPV‐16 and in 20% of cases of HPV‐6. Viral RNA expression was detected by reverse transcription–PCR only in HPV‐16‐positive tumours. The pattern of expression was consistent with an active role of HPV in cellular transformation. In conclusion, the present work suggests that HPV infection may be involved in some cases of laryngeal carcinoma. However, the transformation mechanisms might be different from those currently accepted for anogenital cancers. J. Med. Virol. 60:396–402, 2000.

Expression of endothelin 1 and endothelin A receptor in HPV-associated cervical carcinoma: new potential targets for anticancer therapy

ABSTRACT Human papillomaviruses (HPV) are associated with cervical cancer and interact with growth factors that may enhance malignant transformation of cervical carcinoma cells. Endothelin‐1 (ET‐1) is released from HPV transfected keratinocytes and induces increased growth response in these cell lines in comparison with normal cells. In the present study several cervical carcinoma cell lines have been analyzed to investigate the expression of ET‐1 and its receptors as well as their involvement in tumor growth. All HPV‐positive cancer cells secreted ET‐1 and expressed mRNA for ET‐1 and its receptors, whereas a HPV‐negative carcinoma cell line expressed only the ETBR mRNA and didnt secrete ET‐1. Binding studies showed that HPV‐associated cells expressed an increased number of functional ETAR. ET‐1 stimulated a marked dose‐dependent increase in [3H]‐thymidine incorporation with respect to the normal cells whereas ET‐3 and ETBR agonists had no effect. In HPV‐positive cancer cells, a specific antagonist of ETAR inhibited the proliferation induced by ET‐1 and substantially reduced the basal growth rate of unstimulated cervical tumor cells, whereas the ETBR antagonist had no effect. These results demonstrate that ET‐1 participates in the progression of neoplastic growth in HPV‐associated carcinoma, in which ETAR are increased and could be targeted for antitumor therapy.—Venuti, A., Salani, D., Manni, V., Poggiali, F., Bagnato, A. Expression of endothelin 1 and endothelin A receptor in HPV‐associated cervical carcinoma: new potential targets for anticancer therapy. FASEB J. 14, 2277–2283 (2000)

An E7-based therapeutic vaccine protects mice against HPV16 associated cancer.

Plant-derived vaccines represent an attractive strategy for cancer immunotherapy due to their relative safety and cost-effectiveness. We evaluated the anti-tumour activity of a Nicotiana benthamiana produced vaccine candidate based on the non-transforming E7 protein of HPV-16 fused to beta-1,3-1,4-glucanase of Clostridium thermocellum. Two doses of vaccine at two week intervals were administered to groups of C57BL/6 mice starting 3 or 6 days after challenge with tumourigenic E7-expressing TC-1* cells. Inhibition of tumour growth and increased survival was observed in both groups treated with vaccine. These data suggest the potential of plants as a platform for producing therapeutic vaccines.

Antitumor activity of DNA vaccines based on the human papillomavirus-16 E7 protein genetically fused to a plant virus coat protein.

DNA vaccination represents an attractive strategy for cancer immunotherapy combining vaccine stability, cost-effectiveness, and safety. However, a major problem of genetic vaccination is the limited potency, due to intrinsic lack of amplifying and spreading abilities in vivo and to the suboptimal intracellular processing/presentation of tumor antigens. We explored the therapeutic antitumor potency of DNA vaccines based on a mutated, nontransforming form of the E7 gene (E7GGG gene) of human papilloma virus 16 (HPV-16) fused, with or without a linker, to the potato virus X (PVX) coat protein sequence (PVX-CP). Transfection of mammalian cells demonstrated expression of the E7GGG protein, while the fusion proteins were detected only in the presence of proteasome inhibitors, suggesting increased instability and faster degradation via the proteasome. The DNA fusion vaccines, administered intramuscularly to C57BL/6 mice after challenging with a tumorigenic dose of E7-expressing TC-1 cells, inhibited the growth of tumors in vivo better than the E7GGG gene alone and induced both humoral and cell-mediated immune responses. Therefore, fusion of the HPV-16 E7GGG gene with a plant virus coat protein gene might be a valid strategy to induce antitumor immunity in a safe setting by a novel genetic vaccine targeting cervical carcinoma.

Exploiting the plant secretory pathway to improve the anticancer activity of a plant-derived HPV16 E7 vaccine

The human papillomavirus 16 (HPV16) E7 oncoprotein can be considered a tumor-specific antigen, and therefore it represents a promising target for a therapeutic vaccine against HPV-associated tumors. Efficient production of E7 protein with a plant-based transient expression system has been already described and it was demonstrated that E7-containing crude plant extracts confer partial protection against tumor challenge in a mouse model system. Before adopting the plant-based system as a cost-effective method for the production of an E7-based anti-cancer vaccine, some aspects, such as the oncoprotein yield, need further investigation. In the present study, we report the transient expression, mediated by a potato virus X (PVX)-derived vector, of the E7 protein targeted to the secretory system of Nicotiana benthamiana plants by using a plant-derived signal sequence. Targeting the antigen to the secretory pathway enhanced the E7 protein expression levels about five-fold. Mice immunized by s.c. administration with crude foliar extracts containing E7 showed strong stimulation of cell-mediated immune response after five boosters, as detected by ELISPOT. After challenging with the E7-expressing C3 tumor cells, tumor growth was completely inhibited in 80% of the vaccinated animals and a drastic reduction of tumor burden was observed in the remaining tumor-affected mice. These data demonstrate that, by enhancing E7 yield, it is possible to improve the anti-cancer activity of the plant-based experimental vaccine and open the way for a large-scale production of the E7 protein which could be purified or used as in planta formulation, also suitable for oral therapeutic vaccination.

PBMCs are additional sites of productive infection of bovine papillomavirus type 2.

Bovine papillomavirus type 2 (BPV-2) is an oncogenic virus infecting both epithelial and mesenchymal cells. Its life cycle, similar to other papillomaviruses (PVs), appears to be linked to epithelial differentiation. Human and bovine PVs have been known to reside in a latent, episomal form in PBMCs; therefore, it is believed that blood cells, like all mesenchymal cells, function as non-permissive carriers. Here, for the first time in veterinary and comparative medicine, the BPV-2 E5 oncoprotein and the major structural L1 capsid protein, known to be expressed only in productive infections, were shown to occur in defined subsets of PBMCs. E5 oncoprotein was detected in sorted T- and B-cells as well as in monocytes by flow cytometry and Western blot analysis. However, CD4(+) and CD8(+) lymphocytes appeared to be the main circulating targets of the virus, thus possibly representing the most important reservoir of active BPV-2 in blood. L1 protein was identified by flow cytometry in a population of blood cells recognized as lymphocytes by morphological scatter properties. Western blot analysis was performed on lysates obtained from the sorted subpopulations of PBMCs and detected L1 protein in CD4(+) and CD8(+) cells only. Thus, this study showed that CD4(+) and CD8(+) lymphocytes are permissive for BPV-2 and are new, hitherto unknown sites of productive PV infection. In light of these observations, the life cycle of PVs needs to be revisited to gain novel insights into the epidemiology of BPV infection and the pathogenesis of related diseases.

A Chlamydomonas-Derived Human Papillomavirus 16 E7 Vaccine Induces Specific Tumor Protection

Background The E7 protein of the Human Papillomavirus (HPV) type 16, being involved in malignant cellular transformation, represents a key antigen for developing therapeutic vaccines against HPV-related lesions and cancers. Recombinant production of this vaccine antigen in an active form and in compliance with good manufacturing practices (GMP) plays a crucial role for developing effective vaccines. E7-based therapeutic vaccines produced in plants have been shown to be active in tumor regression and protection in pre-clinical models. However, some drawbacks of in whole-plant vaccine production encouraged us to explore the production of the E7-based therapeutic vaccine in Chlamydomonas reinhardtii, an organism easy to grow and transform and fully amenable to GMP guidelines. Methodology/Principal Findings An expression cassette encoding E7GGG, a mutated, attenuated form of the E7 oncoprotein, alone or as a fusion with affinity tags (His6 or FLAG), under the control of the C. reinhardtii chloroplast psbD 5′ UTR and the psbA 3′ UTR, was introduced into the C. reinhardtii chloroplast genome by homologous recombination. The protein was mostly soluble and reached 0.12% of total soluble proteins. Affinity purification was optimized and performed for both tagged forms. Induction of specific anti-E7 IgGs and E7-specific T-cell proliferation were detected in C57BL/6 mice vaccinated with total Chlamydomonas extract and with affinity-purified protein. High levels of tumor protection were achieved after challenge with a tumor cell line expressing the E7 protein. Conclusions The C. reinhardtii chloroplast is a suitable expression system for the production of the E7GGG protein, in a soluble, immunogenic form. The production in contained and sterile conditions highlights the potential of microalgae as alternative platforms for the production of vaccines for human uses.

Immunologic treatments for precancerous lesions and uterine cervical cancer

Development of HPV-associated cancers not only depends on efficient negative regulation of cell cycle control that supports the accumulation of genetic damage, but also relies on immune evasion that enable the virus to go undetected for long periods of time. In this way, HPV-related tumors usually present MHC class I down-regulation, impaired antigen-processing ability, avoidance of T-cell mediated killing, increased immunosuppression due to Treg infiltration and secrete immunosuppressive cytokines. Thus, these are the main obstacles that immunotherapy has to face in the treatment of HPV-related pathologies where a number of different strategies have been developed to overcome them including new adjuvants. Although antigen-specific immunotherapy induced by therapeutic HPV vaccines was proved extremely efficacious in pre-clinical models, its progression through clinical trials suffered poor responses in the initial trials. Later attempts seem to have been more promising, particularly against the well-defined precursors of cervical, anal or vulvar cancer, where the local immunosuppressive milieu is less active. This review focuses on the advances made in these fields, highlighting several new technologies (such as mRNA vaccine, plant-derived vaccine). The most promising immunotherapies used in clinical trials are also summarized, along with integrated strategies, particularly promising in controlling tumor metastasis and in eliminating cancer cells altogether.After the early promising clinical results, the development of therapeutic HPV vaccines need to be implemented and applied to the users in order to eradicate HPV-associated malignancies, eradicating existing perception (after the effectiveness of commercial preventive vaccines) that we have already solved the problem.