Comparison of HPV16 E7-specific CD8+ T cells induced by HPV16 E7 long peptide after either intramuscular or intracervicovaginal vaccination

Supplementary Figure 7:Detection of CD103 and s1p1 expression by HPV16 E7-specific CD8+ T cells after intracervicovaginal vaccination Supplementary Figure 8: Comparison of HPV16 E7-specific CD8+ T cells induced by pNGVL4a-Sig/E7(detox)/HSP70 intracervicovaginal vaccination followed by either intracervicovaginal or subcutaneous TA-HPV boost

Characterization of MAdCAM-1 expression in cervicovaginal tissue after vaccination

Supplementary Figure Legends

Local and systemic immune responses produced by different vaccination routes

Supplementary Figure 2 from Cancer Immunotherapy Using Irradiated Tumor Cells Secreting Heat Shock Protein 70

Migration of CSFE-labeled α4β7 expressing E7-specific CD8+ T cells into spleen and vagina of WT or Itgb7-/- mice

Comparison of anti-tumor effect generated by either pNGVL4a-Sig/E7(detox)/HSP70 intracervicovaginal vaccination followed by intracervicovaginal TA-HPV boost or intracervicovaginal TA-HPV vaccination

Analysis of HPV16 E7-specific CD8+ T cells after intracervicovaginal vaccination with or without CD4+ T cell depletion

A common drawback of many cancer immunotherapies,includ-ing immune checkpoint blockade,is their reliance on the expression of immunogenic tumor antigens by cancer cells for immune recognition and clearance,which limits their efficacy against cancers with weak antigenicity.1 To overcome this obstacle,we and others have explored strategies to harness the immune responses against nontumor antigens and redirect those immune responses to target tumor cells.2-5 In particular,we have pioneered a therapeutic strategy fusing tumor-targeting proteins with known antigenic peptide epitopes not naturally expressed by tumor cells,which are flanked by peptide sequences that can be recognized and cleaved by proteases overexpressed in most cancers.2,3 This strategy facilitates the targeted delivery of immunogenic peptides into tumor foci,the release of immunogenic peptides into the tumor microenviron-ment(TME)via tumor protease cleavage,and subsequent loading of these peptides onto major histocompatibility complex class 1(MHC-I)on the tumor cell surface,allowing the recognition of coated tumor cells by the respective peptide-specific cytotoxic CD8+T lymphocytes(CTLs)for elimination.

Myeloid-derived-suppressor cells (MDSCs) are key mediators of immune suppression in the ovarian tumor microenvironment. Modulation of MDSC function to relieve immunosuppression may enhance the immunologic clearance of tumors. The bis-benzylidine piperidone RA190 binds to the ubiquitin receptor RPN13/ADRM1 on the 19S regulatory particle of the proteasome and directly kills ovarian cancer cells by triggering proteotoxic stress. Here we examine the effect of RA190 treatment on the immunosuppression induced by MDSCs in the tumor microenvironment, specifically on the immunosuppression induced by MDSCs. We show that RA190 reduces the expression of Stat3 and the levels of key immunosuppressive enzymes and cytokines arginase, iNOS, and IL-10 in MDSCs, while boosting expression of the immunostimulatory cytokine IL-12. Furthermore, we show that the RA190-treated MDSCs lost their capacity to suppress CD8+ T cell function. Finally, we show that RA190 treatment of mice bearing syngeneic ovarian tumor elicits potent CD8+ T cell antitumor immune responses and improves tumor control and survival. These data suggest the potential of RA190 for ovarian cancer treatment by both direct killing of tumor cells via proteasome inhibition and relief of MDSC-mediated suppression of CD8 T cell-dependent antitumor immunity elicited by the apoptotic tumor cells.

Abstract Purpose: Two viral oncoproteins, E6 and E7, are expressed in all human papillomavirus (HPV)–infected cells, from initial infection in the genital tract to metastatic cervical cancer. Intramuscular vaccination of women with high-grade cervical intraepithelial neoplasia (CIN2/3) twice with a naked DNA vaccine, pNGVL4a-sig/E7(detox)/HSP70, and a single boost with HPVE6/E7 recombinant vaccinia vaccine (TA-HPV) elicited systemic HPV-specific CD8 T-cell responses that could traffic to the lesion and was associated with regression in some patients (NCT00788164). Experimental Design: Here, we examine whether alteration of this vaccination regimen by administration of TA-HPV vaccination in the cervicovaginal tract, rather than intramuscular (IM) delivery, can more effectively recruit antigen-specific T cells in an orthotopic syngeneic mouse model of HPV16+ cervical cancer (TC-1 luc). Results: We found that pNGVL4a-sig/E7(detox)/HSP70 vaccination followed by cervicovaginal vaccination with TA-HPV increased accumulation of total and E7-specific CD8+ T cells in the cervicovaginal tract and better controlled E7-expressing cervicovaginal TC-1 luc tumor than IM administration of TA-HPV. Furthermore, the E7-specific CD8+ T cells in the cervicovaginal tract generated through the cervicovaginal route of vaccination expressed the α4β7 integrin and CCR9, which are necessary for the homing of the E7-specific CD8+ T cells to the cervicovaginal tract. Finally, we show that cervicovaginal vaccination with TA-HPV can induce potent local HPV-16 E7 antigen-specific CD8+ T-cell immune responses regardless of whether an HPV DNA vaccine priming vaccination was administered IM or within the cervicovaginal tract. Conclusions: Our results support future clinical translation using cervicovaginal TA-HPV vaccination. Clin Cancer Res; 22(3); 657–69. ©2015 AACR. See related commentary by Nizard et al., p. 530

Background: There is an urgent need to develop targeted therapies for the control of advanced stage ovarian cancer because it is the most deadly gynecologic cancer. Antigen-specific immunotherapy is a promising approach because of the potential of the immune system to specifically target tumors without the toxicity associated with traditional chemoradiation. However, one of the major limitations for antigen-specific cancer immunotherapy is the pre-existing immune tolerance against endogenous targeted tumor antigens that frequently evolves during carcinogenesis. Here, we described the creation of a therapeutic agent comprised of a tumor-homing module fused to a functional domain capable of selectively rendering tumor cells sensitive to foreign antigen-specific CD8+ T cell-mediated immune attack, thereby circumventing many aspects of immune tolerance. The tumor-homing module, NKG2D, specifically binds to NKG2D ligand that is commonly overexpressed in ovarian tumors. The functional domain is comprised of the Fc portion of IgG2a protein and foreign immunogenic CD8+ T cell epitope flanked by furin cleavage sites (R), which can be recognized and cleaved by furin that is highly expressed in the tumor microenvironment.Results: We show that this therapeutic chimeric protein specifically loaded antigenic epitope onto the surface of NKG2D ligand-expressing ovarian tumor cells, rendering ovarian tumors susceptible to antigen-specific CTL-mediated killing in vitro. Furthermore, we show that intraperitoneal administration of our therapeutic chimeric protein followed by adoptive transfer of antigen-specific CD8+ T cells generates potent antitumor effects and significant accumulation of antigen-specific CD8+ T cells in the tumor loci.Conclusions: Our findings have promise for bypassing immune tolerance to enhance cancer immunotherapy.

The HPV oncoproteins E6 and E7 are consistently expressed in HPV-associated cancer cells and are responsible for their malignant transformation. Therefore, HPV E6 and E7 are ideal target antigens for developing vaccines and immunotherapeutic strategies against HPV-associated neoplasms. Recently, it has been demonstrated that codon optimization of the HPV-16 E7 gene resulted in highly efficient translation of E7 and increased the immunogenicity of E7-specific DNA vaccines. Since vaccines targeting E6 also represent an important strategy for controlling HPV-associated lesions, we developed a codon-optimized HPV-16 E6 DNA vaccine (pNGVL4a-E6/opt) and characterized the E6-specific CD8+ T cell immune responses as well as the protective and therapeutic anti-tumor effects in vaccinated C57BL/6 mice. Our data indicated that transfection of human embryonic kidney cells (293 cells) with pNGVL4a-E6/opt resulted in highly efficient translation of E6. In addition, vaccination with pNGVL4a-E6/opt significantly enhanced E6-specific CD8+ T cell immune responses in C57BL/6 mice. Mice vaccinated with pNGVL4a-E6/opt are able to generate potent protective and therapeutic antitumor effects against challenge with E6-expressing tumor cell line, TC-1. Thus, DNA vaccines encoding a codon-optimized HPV-16 E6 may be a promising strategy for improving the potency of prophylactic and therapeutic HPV vaccines with potential clinical implications.

Human papillomavirus (HPV) E6 and E7 are consistently expressed and are responsible for the malignant transformation of HPV-associated lesions. Thus, E6 and E7 represent ideal targets for therapeutic HPV vaccine development. We have previously used the gene gun approach to test several intracellular targeting and intercellular spreading strategies targeting HPV-16 E7. These strategies include the use of the sorting signal of lysosome-associated membrane protein (LAMP-1), Mycobacterium tuberculosis heat shock protein 70 (HSP70), calreticulin (CRT) and herpes simplex virus type 1 (HSV-1) VP22 proteins. All of these strategies have been shown to be capable of enhancing E7-DNA vaccine potency. In the current study, we have characterized DNA vaccines employing these intracellular targeting or intercellular spreading strategies targeting HPV-16 E6 for their ability to generate E6-specific CD8+ T cell immune responses and antitumor effects against an E6-expressing tumor cell line, TC-1, in C57BL/6 mice. We found that all the intracellular targeting strategies (CRT, LAMP-1, HSP70) as well as the intercellular spreading strategy (VP22) were able to enhance E6 DNA vaccine potency, although the orientation of HSP70 linked to E6 antigen in the E6 DNA vaccine appears to be important for the HSP70 strategy to work. The enhanced E6-specific CD8+ T cell immune response in vaccinated mice also translated into potent antitumor effects against TC-1 tumor cells. Our data indicate that all of the intracellular targeting and intercellular spreading strategies that have been shown to enhance E7 DNA vaccine potency were also able to enhance E6 DNA vaccine potency.