Enhancement of human papilloma virus type 16 E7 specific T cell responses by local invasive procedures in patients with (pre)malignant cervical neoplasia

Immunomodulation to enhance the efficacy of an HPV therapeutic vaccine

BACKGROUND

While prophylactic human papillomavirus (HPV) vaccines will certainly reduce the incidence of HPV-associated cancers, these malignancies remain a major health issue. PDS0101 is a liposomal-based HPV therapeutic vaccine consisting of the immune activating cationic lipid R-DOTAP and HLA-unrestricted HPV16 peptides that has shown in vivo CD8+ T cell induction and safety in a phase I study. In this report, we have employed the PDS0101 vaccine with two immune modulators previously characterized in preclinical studies and which are currently in phase II clinical trials. Bintrafusp alfa (M7824) is a first-in-class bifunctional fusion protein composed of the extracellular domains of the transforming growth factor-β receptor type II (TGFβRII) fused to a human IgG₁ monoclonal antibody blocking programmed cell death protein-1 ligand (PDL1), designed both as a checkpoint inhibitor and to bring the TGFβRII 'trap' to the tumor microenvironment (TME). NHS-interleukin-12 (NHS-IL12) is a tumor targeting immunocytokine designed to bring IL-12 to the TME and thus enhance the inflammatory Th1 response.

METHODS

We employed TC-1 carcinoma (expressing HPV16 E6 and E7 and devoid of PDL1 expression) in a syngeneic mouse model in monotherapy and combination therapy studies to analyze antitumor effects and changes in immune cell types in the spleen and the TME.

RESULTS

As a monotherapy, the PDS0101 vaccine generated HPV-specific T cells and antitumor activity in mice bearing HPV-expressing mEER oropharyngeal and TC-1 lung carcinomas. When used as a monotherapy in the TC-1 model, NHS-IL12 elicited antitumor effects as well as an increase in CD8+ T cells in the TME. When used as a monotherapy, bintrafusp alfa did not elicit antitumor effects or any increase in T cells in the TME. When all three agents were used in combination, maximum antitumor effects were observed, which correlated with increases in T cells and T-cell clonality in the TME.

CONCLUSION

These studies provide the rationale for the potential clinical use of combinations of agents that can (1) induce tumor-associated T-cell responses, (2) potentiate immune responses in the TME and (3) reduce immunosuppressive entities in the TME.

Immunotherapy of human papilloma virus induced disease

Immunotherapy is the generic name for treatment modalities aiming to reinforce the immune system against diseases in which the immune system plays a role. The design of an optimal immunotherapeutic treatment against chronic viruses and associated diseases requires a detailed understanding of the interactions between the target virus and its host, in order to define the specific strategies that may have the best chance to deliver success at each stage of disease. Recently, a first series of successes was reported for the immunotherapy of Human Papilloma Virus (HPV)-induced premalignant diseases but there is definitely room for improvement. Here I discuss a number of topics that in my opinion require more study as the answers to these questions allows us to better understand the underlying mechanisms of disease and as such to tailor treatment.

The detection of circulating human papillomavirus-specific T cells is associated with improved survival of patients with deeply infiltrating tumors

A detailed analyses of HPV-specific immunity was performed in a large group of patients with HPV-induced cervical cancer (CxCa) in relation to HLA-types and prognostic factors. Patients were HLA-typed and HPV16/18-specific T-cell immunity was assessed by proliferation assay and cytometric bead array using freshly isolated PBMC and by phenotypic analysis of HPV-specific T cells. The results were analyzed in relation to known disease-related HLA-types (DR7, DR13, DR15/DQ06), invasion-depth and size of tumor, lymph node (LN) status and disease free survival. In total 119 HLA-typed patients with CxCa were analyzed. Patients expressing the HLA-DR13 haplotype were underrepresented as compared to the Dutch population (p = 0.014), whereas HLA-DR7 was overrepresented in patients with HPV16+ CxCa (p = 0.006). In 29 of 94 patients (31%) from whom blood could be tested, a proliferative response to HPV16/18 was detected, which was associated with increased numbers of HPV-specific CD4+CD25+ (activated) T cells (p = 0.03) and HPV-specific CD4+CD25+FoxP3-positive T cells (p = 0.04). The presence of both FoxP3-positive and negative HPV-specific CD4+CD25+ T cells was significantly correlated (p = 0.01). Interestingly, the detection of HPV-specific proliferation was associated with invasion depth (p = 0.020) but not with HLA type, tumor size nor LN status. Moreover, the detection of HPV-specific immunity was associated with an improved disease free survival (p = 0.04) in patients with deeply infiltrating tumors. In conclusion, HPV-specific proliferative T-cell response, comprising higher percentages of HPV-specific CD25+ and CD25+FoxP3-positive CD4+T cells, are more frequently detected in patients with deep infiltrating CxCa tumors and associated with an improved survival.

Human Immunodeficiency Virus and Human Papilloma Virus - why HPV-induced lesions do not spontaneously resolve and why therapeutic vaccination can be successful

HIV and HPV can both cause chronic infections and are acquired during sexual contact. HIV infection results in a progressive loss of CD4+ T cells that is associated with an increased prevalence of HPV infections, type-specific persistence and an increase in HPV-associated malignancies. On the one hand this illustrates the important role of HPV-specific CD4+ helper T-cell immunity, on the other it shows the Achilles heel of the HPV-specific immune response. The use of highly active antiretroviral therapy (HAART) results in a rapid reduction of HIV and a reconstitution of systemic CD4+ T-cell levels. The use of HAART thus has the potential to raise immunity to HPV but to the surprise of many, the incidence of HPV-induced diseases has increased rather than declined since the introduction of HAART. Here, the knowledge on how HPV-induced diseases develop in the face of a non-compromised immune system will be used to explain why the effect of HAART on HPV-induced diseases is modest at best. Furthermore, exciting new data in the field of therapeutic vaccines against HPV will be discussed as this may form a more durable and clinically successful therapeutic approach for the treatment of HPV-induced high-grade lesions in HIV-positive subjects on HAART.

Methylation markers for CCNA1 and C13ORF18 are strongly associated with high-grade cervical intraepithelial neoplasia and cervical cancer in cervical scrapings

PURPOSE

Recently, we reported 13 possible cervical cancer-specific methylated biomarkers identified by pharmacologic unmasking microarray in combination with large-genome computational screening. The aim of the present study was to perform an in-depth analysis of the methylation patterns of these 13 candidate genes in cervical neoplasia and to determine their diagnostic relevance.

EXPERIMENTAL DESIGN AND RESULTS

Five of the 13 gene promoters (C13ORF18, CCNA1, TFPI2, C1ORF166, and NPTX1) were found to be more frequently methylated in frozen cervical cancer compared with normal cervix specimens. Quantitative methylation analysis for these five markers revealed that both CCNA1 and C13ORF18 were methylated in 68 of 97 cervical scrapings from cervical cancer patients and in only 5 and 3 scrapings, respectively, from 103 healthy controls (P < 0.0005). In cervical scrapings from patients referred with an abnormal Pap smear, CCNA1 and C13ORF18 were methylated in 2 of 43 and 0 of 43 CIN 0 (no cervical intraepithelial neoplasia) and in 1 of 41 and 0 of 41 CIN I, respectively. Furthermore, 8 of 43 CIN II, 22 of 43 CIN III, and 3 of 3 microinvasive cancer patients were positive for both markers. Although sensitivity for CIN II or higher (for both markers 37%) was low, specificity (96% and 100%, respectively) and positive predictive value (92% and 100%, respectively) were high.

CONCLUSION

Methylation of CCNA1 and C13ORF18 in cervical scrapings is strongly associated with CIN II or higher-grade lesions. Therefore, these markers might be used for direct referral to gynecologists for patients with a methylation-positive scraping.

Serological response to an HPV16 E7 based therapeutic vaccine in women with high-grade cervical dysplasia

PURPOSE

Infection with oncogenic human papillomaviruses has been linked to the development of cervical neoplasia and cancer. The exclusive expression of E7, a viral oncogene, in infected cells makes this protein an ideal target for immunotherapy. We recently reported on the results of a trial in women with cervical carcinoma-in-situ using HspE7, a protein vaccine consisting of full length HPV16 E7 linked to a heat shock protein from M. bovis. The stimulating effects of HspE7 on specific cytotoxic T lymphocytes have been demonstrated in vitro and in (pre-)clinical trials. The induction of a B-cell response by HspE7 and its association with clinical outcome is unknown, and is the purpose of this study.

EXPERIMENTAL DESIGN

We measured the serum IgG levels against HPV16 E7 and HPV16 and -18 VLPs using a multiplexed Luminex based assay in 57 women with CIS who received the HspE7 vaccine.

RESULTS

Vaccination with HspE7 results in a modest, yet maintained increase in HPV16 E7 specific IgG levels. While not significant, increased HPV16 E7 IgG levels appear to be correlated with a positive therapeutic effect. Women who were previously treated for recurrent disease (by LEEP) had significantly higher HPV16 E7 IgG levels compared with subjects without recurrent disease (p=0.01). In women with recurrent disease, higher IgG levels correlated with complete pathological response.

CONCLUSIONS

This study suggests that IgG levels could potentially be used as a marker for response to a therapeutic vaccine. Further translational investigations of the 'priming' of local immune responses using extirpative procedures should be explored.

Surgery followed by persistence of high-grade squamous intraepithelial lesions is associated with the induction of a dysfunctional HPV16-specific T-cell response

PURPOSE

To characterize HPV16 E6- and E7-specific T-cell immunity in patients with high-grade squamous intraepithelial lesions (HSIL).

EXPERIMENTAL DESIGN

Peripheral blood mononuclear cells isolated from 38 patients with HPV16+ HSIL were used to determine the magnitude, breadth, and polarization of HPV16-specific T-cell responses by proliferation assays and cytokine assays. Furthermore, HSIL-infiltrating T cells isolated from 7 cases were analyzed for the presence of HPV16 E6- and/or E7-specific T cells, phenotyped, and tested for the specific production of IFN-gamma and interleukin-10 as well as for their capacity to suppress immune responses.

RESULTS

HPV16-specific T-cell responses were absent in the circulation of the majority (approximately 60%) of patients who visit the clinic for treatment of a HPV16+ HSIL lesion. Notably, HPV16-specific T-cell reactivity was predominantly detected in patients returning to the clinic for repetitive treatment of a persistent or recurrent HPV16+ HSIL lesion after initial destructive treatment. The majority (> 70%) of these HPV16-specific T-cell responses did not secrete proinflammatory cytokines, indicating that most of the subjects, although in principle able to mount a HPV16-specific immune response, fail to develop protective cellular immunity. This notion is sustained by our observation that only three HSIL-infiltrating T-cell cultures contained HPV16-specific T cells, one of which clearly consisted of HPV16 E7-specific regulatory T cells.

CONCLUSIONS

The presence of HPV16-specific T cells with a non-Th1/Th2 cytokine and even suppressive signature in patients with HSIL may affect the outcome of vaccine approaches aiming at reinforcing human papillomavirus-specific immunity to attack human papillomavirus-induced lesions.

Increase of human papillomavirus-16 E7-specific T helper type 1 response in peripheral blood of cervical cancer patients after radiotherapy

It has been suggested that tumour cell lysis by gamma-radiation induces a tumoral antigen release eliciting an immune response. It is not clear how a specific immune response in cervical cancer patients is developed after radiotherapy. This study is an attempt to investigate the role of the human papillomavirus type 16 (HPV-16) E7-specific T helper response before and after radiotherapy. Lymphocytes were isolated from 32 cervical cancer patients before and after radiotherapy and from 16 healthy women. They were stimulated for 12 hr with autologous HPV-16 E7-pulsed monocyte-derived dendritic cells or directly with HPV-16 E7 synthetic peptides: E7(51-70), E7(65-84) and E7(79-98). The cells were stained for CD4, CD69, intracellular interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) cytokines and analysed by flow cytometry. A specific CD4(+) CD69(+) IFN-gamma(+) immune response against HPV-16 E7(79-98) peptide was observed in 10 of 14 patients (71.4%) after treatment, compared with 4 of 14 (28.5%) before radiotherapy (P = 0.039); however, this response was not associated with a successful clinical response. Before treatment, 5 of 31 patients showed a HPV-16 E7(79-98)-specific T helper type 2 (Th2) response. Interestingly, this response was significantly associated with a decrease in disease-free survival (P = 0.027). These results suggest that a Th2-type cellular response could be useful as a predictor of recurrence and poor prognosis. An increase of the HPV-specific immune response was observed after radiotherapy; however, it is not enough to control completely the disease after treatment. Our results support that the E7-specific T-cell IFN-gamma response in cervical cancer patients, rather than reflecting the host's capability of controlling tumour growth, might be an indicator for disease severity.

Frequencies and role of regulatory T cells in patients with (pre)malignant cervical neoplasia

Oncogenic human papillomavirus (HPV)-infection is crucial for developing cervical cancer and its precursor lesions [cervical intraepithelial neoplasia (CIN)]. Regulatory T cells (T(regs)) might be involved in the failure of the immune system to control the development of HPV-induced cancer. We investigated frequencies, phenotype and activity of T(regs) in patients with cervical neoplasia. CIN and cervical cancer patients showed increased CD4(+)/CD25(high) T cell frequencies in peripheral blood and CD4(+) T cell fraction. These CD4(+)/CD25(high) T cells represent T(regs) as demonstrated by their low proliferation rate, low interferon (IFN)-gamma/interleukin (IL)-10 ratio, high expression of CD45RO, GITR, CTLA-4, forkhead box P3 (FoxP3) and low CD45RA expression. Moreover, in HPV16(+) cervical cancer patients, in-vitro depletion of CD25(+) T cells resulted in increased IFN-gamma T cell responses against HPV16 E6- and E7 peptides. Thus, increased frequencies of T(regs) in cervical cancer patients may indeed suppress HPV-specific immunity. Longitudinal analysis of CD4(+)/CD25(high) T cell frequencies in patients showed a modest decline 1 year after curative surgery or chemoradiation. This study demonstrates increased frequencies and suppressive activity of T(regs) in cervical cancer. These results imply that T(regs) may suppress the immune control of cervical neoplasia and furthermore that suppression of immunity by T(regs) will be another hurdle to overcome in therapeutic immunization strategies against cervical neoplasia.

Human papillomavirus therapeutic vaccines in head and neck tumors

Head and neck cancer represents one of the most challenging diseases as the mortality remains high despite advances in early diagnosis and treatment. Human papillomavirus has been implicated in a third of head and neck squamous cell carcinomas and human papillomavirus type 16 is strongly associated with carcinomas arising from the oropharynx, the tonsil being the preferred infected site. Novel therapeutic approaches including immunotherapy are currently under investigation. Immune vaccines developed against human papillomavirus in the genital area are already available and could simultaneously protect other anatomical localizations; however, prophylactic vaccines are expected to be effective in reducing the incidence of tumors after many years and, therefore, there is an urgent need to improve therapeutic interventions, such as immunotherapy. To date, human papillomavirus therapeutic vaccines are either at the preclinical level or at early phase human trials for genital pathologies. Nevertheless, accumulating evidence from animal and clinical studies suggests that the enhancement of specific and innate immune responses is effective in clearance of the human papillomavirus infection, promoting a cautious optimism regarding the achievement of an efficacious immunotherapy. This article reviews what has been achieved and what remains to be done in the field for the development of future viral vaccines in head and neck tumors.

DNA vaccine encoding endosome-targeted human papillomavirus type 16 E7 protein generates CD4+ T cell-dependent protection

Human papillomavirus type 16 is commonly implicated in cervical cancers. The viral genome encodes potential targets like the oncoprotein E7, expressed in transformed cells but thought to represent a poorly immunogenic antigen. We describe in this work a DNA-based vaccination protocol aimed at inducing an efficient anti-E7 immune response in vivo. Plasmids allowing the expression of the E7 protein in distinct cellular compartments were generated and assayed in an in vivo model of tumor growth. Our data demonstrate that mice vaccinated with a plasmid encoding for an E7 protein fused to a domain of the MHC class II-associated invariant chain (IiE7) were protected against tumor challenge. Mice immunized against an ubiquitinated form of E7 (Ub(Ala)E7) failed to control tumor growth. Protection induced by IiE7 was correlated with the development of CD8+ CTL and required the presence of CD4+ cells. In vitro studies confirmed that the IiE7 fusion protein was expressed at high levels in the endosomal compartment of transfected cells, while the natural and the ubiquitin-modified form of E7 were mainly nuclear. The present study suggests that an efficient anti-tumor response can be induced in vivo by DNA constructs encoding for E7 protein forms localizing at the endosomal compartment.

Assessment of gene promoter hypermethylation for detection of cervical neoplasia

Current cervical cancer screening is based on morphological assessment of Pap smears and associated with significant false negative and false positive results. Previously, we have shown that detection of hypermethylated genes in cervical scrapings using quantitative methylation-specific PCR (QMSP) is a promising tool for identification of squamous cell cervical cancer. Aim of the present pilot-study was to evaluate presence of hypermethylated genes in cervical carcinogenesis, both in squamous cell as well as adenocarcinomas. Cervical scrapings were obtained from 30 patients diagnosed with cervical cancer (20 squamous cell carcinomas and 10 adenocarcinomas) and 19 women with histologically normal cervices. The scraped cells were used for determination of promoter hypermethylation by QMSP for 12 genes and for morphological assessment. Overall, CALCA, DAPK, ESR1, TIMP3, APC and RAR-beta2 promoters were significantly more often hypermethylated in cancers than in controls, while adenocarcinomas were more often hypermethylated above the highest control ratio for APC, TIMP3 and RASSF1A promoters. Combining 4 genes (CALCA, DAPK, ESR1 and APC) yielded a sensitivity of 89% (with all adenocarcinomas identified), equal to cytomorphology (89%) and high-risk human papilloma virus (Hr-HPV; 90%). The 4-gene QMSP proved theoretically superior to cytomorphology as well as Hr-HPV in specificity (100% vs. 83 and 68%, respectively), because cytology identified 3 controls as moderate or severe dyskaryosis and 6 controls were positive for Hr-HPV. In conclusions, QMSP of 4 gene promoters combined appears to have comparable sensitivity and potentially better specificity in comparison to "classic" cytomorphological assessment and Hr-HPV detection. QMSP holds promise as a new diagnostic tool for both squamous cell carcinoma and adenocarcinoma of the cervix.

Recombinant alphaviruses as vectors for anti-tumour and anti-microbial immunotherapy

BACKGROUND

Vectors derived from alphaviruses are gaining interest for their high transfection potency and strong immunogenicity.

OBJECTIVES

After a brief introduction on alphaviruses and their vectors, an overview is given on current preclinical immunotherapy studies using vector systems based on alphaviruses. The efficacy of alphavirus vectors in inducing immune responses will be illustrated by a more detailed description of immunization studies using recombinant Semliki Forest virus for the treatment of human papilloma virus-induced cervical cancer.

RESULTS

Immunization with recombinant alphavirus results in the induction of humoral and cellular immune responses against microbes, infected cells and cancer cells. Preclinical studies demonstrate that infectious diseases and cancer can be treated prophylactically as well as therapeutically.

CONCLUSIONS

Alphavirus-based genetic immunization strategies are highly effective in animal model systems, comparing quite favourably with any other approach. Therefore, we hope and expect to see an efficient induction of tumour-or microbial immunity and a positive outcome in future clinical efficacy studies.