Tumor-derived GDF-15 blocks LFA-1 dependent T cell recruitment and suppresses responses to anti-PD-1 treatment

Immune checkpoint blockade therapy is beneficial and even curative for some cancer patients. However, the majority don't respond to immune therapy. Across different tumor types, pre-existing T cell infiltrates predict response to checkpoint-based immunotherapy. Based on in vitro pharmacological studies, mouse models and analyses of human melanoma patients, we show that the cytokine GDF-15 impairs LFA-1/β2-integrin-mediated adhesion of T cells to activated endothelial cells, which is a pre-requisite of T cell extravasation. In melanoma patients, GDF-15 serum levels strongly correlate with failure of PD-1-based immune checkpoint blockade therapy. Neutralization of GDF-15 improves both T cell trafficking and therapy efficiency in murine tumor models. Thus GDF-15, beside its known role in cancer-related anorexia and cachexia, emerges as a regulator of T cell extravasation into the tumor microenvironment, which provides an even stronger rationale for therapeutic anti-GDF-15 antibody development.

Intratumoral HPV16-Specific T Cells Constitute a Type I-Oriented Tumor Microenvironment to Improve Survival in HPV16-Driven Oropharyngeal Cancer

Purpose: Human papillomavirus (HPV)-associated oropharyngeal squamous cell cancer (OPSCC) has a much better prognosis than HPV-negative OPSCC, and this is linked to dense tumor immune infiltration. As the viral antigens may trigger potent immunity, we studied the relationship between the presence of intratumoral HPV-specific T-cell responses, the immune contexture in the tumor microenvironment, and clinical outcome.Experimental Design: To this purpose, an in-depth analysis of tumor-infiltrating immune cells in a prospective cohort of 97 patients with HPV16-positive and HPV16-negative OPSCC was performed using functional T-cell assays, mass cytometry (CyTOF), flow cytometry, and fluorescent immunostaining of tumor tissues. Key findings were validated in a cohort of 75 patients with HPV16-positive OPSCC present in the publicly available The Cancer Genome Atlas database.Results: In 64% of the HPV16-positive tumors, type I HPV16-specific T cells were present. Their presence was not only strongly related to a better overall survival, a smaller tumor size, and less lymph node metastases but also to a type I-oriented tumor microenvironment, including high numbers of activated CD161⁺ T cells, CD103⁺ tissue-resident T cells, dendritic cells (DC), and DC-like macrophages.Conclusions: The viral antigens trigger a tumor-specific T-cell response that shapes a favorable immune contexture for the response to standard therapy. Hence, reinforcement of HPV16-specific T-cell reactivity is expected to boost this process. Clin Cancer Res; 24(3); 634-47. ©2017 AACRSee related commentary by Laban and Hoffmann, p. 505.

Human Papillomavirus Downregulates the Expression of IFITM1 and RIPK3 to Escape from IFNγ- and TNFα-Mediated Antiproliferative Effects and Necroptosis

The clearance of a high-risk human papillomavirus (hrHPV) infection takes time and requires the local presence of a strong type 1 cytokine T cell response, suggesting that hrHPV has evolved mechanisms to resist this immune attack. Using an unique system for non, newly, and persistent hrHPV infection, we show that hrHPV infection renders keratinocytes (KCs) resistant to the antiproliferative- and necroptosis-inducing effects of IFNγ and TNFα. HrHPV-impaired necroptosis was associated with the upregulation of several methyltransferases, including EZH2, and the downregulation of RIPK3 expression. Restoration of RIPK3 expression using the global histone methyltransferase inhibitor 3-deazaneplanocin increased necroptosis in hrHPV-positive KCs. Simultaneously, hrHPV effectively inhibited IFNγ/TNFα-mediated arrest of cell growth at the S-phase by downregulating IFITM1 already at 48 h after hrHPV infection, followed by an impaired increase in the expression of the antiproliferative gene RARRES1 and a decrease of the proliferative gene PCNA. Knockdown of IFITM1 in uninfected KCs confirmed its role on RARRES1 and its antiproliferative effects. Thus, our study reveals how hrHPV deregulates two pathways involved in cell death and growth regulation to withstand immune-mediated control of hrHPV-infected cells.

A phase 1/2 study combining gemcitabine, Pegintron and p53 SLP vaccine in patients with platinum-resistant ovarian cancer

Purpose

Preclinical tumor models show that chemotherapy has immune modulatory properties which can be exploited in the context of immunotherapy. The purpose of this study was to determine the feasibility and immunogenicity of combinations of such an immunomodulatory chemotherapeutic agent with immunotherapy, p53 synthetic long peptide (SLP) vaccine and Pegintron (IFN-α) in patients with platinum-resistant p53-positive epithelial ovarian cancer (EOC).

Experimental design

This is a phase 1/2 trial in which patients sequential 6 cycles of gemcitabine (1000 mg/kg² iv; n = 3), gemcitabine with Pegintron before and after the first gemcitabine cycle (Pegintron 1 μg/kg sc; n = 6), and gemcitabine and Pegintron combined with p53 SLP vaccine (0.3 mg/peptide, 9 peptides; n = 6). At baseline, 22 days after the 2^nd and 6^th cycle, blood was collected for immunomonitoring. Toxicity, CA-125, and radiologic response were evaluated after 3 and 6 cycles of chemotherapy.

Results

None of the patients enrolled experienced dose-limiting toxicity. Predominant grade 3/4 toxicities were nausea/vomiting and dyspnea. Grade 1/2 toxicities consisted of fatigue (78%) and Pegintron-related flu-like symptoms (72%). Gemcitabine reduced myeloid-derived suppressor cells (p = 0.0005) and increased immune-supportive M1 macrophages (p = 0.04). Combination of gemcitabine and Pegintron stimulated higher frequencies of circulating proliferating CD4+ and CD8+ T-cells but not regulatory T-cells. All vaccinated patients showed strong vaccine-induced p53-specific T-cell responses.

Conclusion

Combination of gemcitabine, the immune modulator Pegintron and therapeutic peptide vaccination is a viable approach in the development of combined chemo-immunotherapeutic regimens to treat cancer.

Abstract 5035A: Intratumoral HPV16-specific T-cells determine clinical outcome of HPV16+ oropharyngeal carcinomas

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer. While the number of HNSCC cases is decreasing, the number of oropharyngeal SCC (OSCC) is rising, especially in young adults. OSCC are increasingly (45-90%) caused by human papillomavirus type 16 (HPV16). Intriguingly, patients with HPV-induced OSCC respond better to therapy than HPV-negative OSCC. This is independent of nodal status, age, stage, tumor differentiation or gender. We hypothesized that the expression of the viral antigens E6 and E7 in HPV16+ OSCC equips the immune system with two strong tumor-specific antigens resulting in the development of a type 1 T-cell immune contexture supporting the better response of HPV+ OSCC to standard therapy.

To test our hypothesis we studied 87 patients with OSCC. The tumors of these patients were tested for the presence of HPV by GP5+/6+ PCR and the expression of p16 by immunohistochemistry. Moreover, fresh tumor tissue was dispersed, cryopreserved and subsequently used for in-depth analyses regarding the composition of the leukocyte infiltrates using a large set of antibodies either by CyTOF or BD Fortessa. In addition, T-cell reactivity was tested directly ex vivo and after a short-term culture period.

57% of OSCC patients were HPV16+ and they showed the best overall survival (p<0.0001, HR 6.9). Whereas none of 37 HPV-negative patients displayed intratumoral HPV16 E6/E7-specific T-cell reactivity this was detected in 25 of 40 (63%) HPV16+ OSCC. Notably, for most patients these T-cells were already detectable directly ex vivo, indicative for their activity in vivo. The presence of intratumoral HPV16-specific T-cell reactivity for the response of patients to therapy was extremely important for a better clinical outcome (p = 0.0003, HR 23.9) as estimated by Kaplan-Meier curves and log-rank analysis. Division of HPV16+ patients on the basis of p16 expression revealed that p16+ patients had a much better clinical outcome (p<0.0001, HR 11.8). In line with the notion that overexpression of p16 is directly associated with expression of the HPV16 E6 and E7 oncogenes, a strong association between p16 expression and HPV16-specific TIL reactivity was found (p<0.0001).

Mechanistically, we found that OSCC cell lines promoted the differentiation of monocytes to M2 macrophages. In vitro experiments showed that the presence of HPV-specific T-cell secreted cytokines prevented this and was even able to redifferentiate macrophages into better antigen-presenting cells, both phenotypically (including co-stimulatory molecules) and functionally (more IL-12 and less IL-10 production). In addition, these cytokines mediated a direct effect on the tumor cell proliferation and metabolism, thereby slowing down tumor growth as well as changing their impact on myeloid cells in the tumor microenvironment.

In conclusion, HPV-specific T cells elicited by HPV+ OSCC are highly predictive for response to therapy.

Citation Format: Marij J. Welters, Lilly-Ann van der Velden, Vanessa J. van Ham, Ilina Ehsan, Renske Goedemans, Saskia J. Santegoets, Sjoerd H. van der Burg. Intratumoral HPV16-specific T-cells determine clinical outcome of HPV16+ oropharyngeal carcinomas. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5035A.

A beneficial tumor microenvironment in oropharyngeal squamous cell carcinoma is characterized by a high T cell and low IL-17(+) cell frequency

Patients with HPV-positive oropharyngeal squamous cell carcinomas (OPSCCs) have a better prognosis than patients with non-HPV-induced OPSCC. The role of the immune response in this phenomenon is yet unclear. We studied the number of T cells, regulatory T cells (Tregs), T helper 17 (Th17) cells and IL-17⁺ non-T cells (mainly granulocytes) in matched HPV-positive and HPV-negative OPSCC cases (n = 162). Furthermore, the production of IFN-γ and IL-17 by tumor-infiltrating T cells was analyzed. The number of tumor-infiltrating T cells and Tregs was higher in HPV-positive than HPV-negative OPSCC (p < 0.0001). In contrast, HPV-negative OPSCC contained significantly higher numbers of IL-17⁺ non-T cells (p < 0.0001). Although a high number of intra-tumoral T cells showed a trend toward improved survival of all OPSCC patients, their prognostic effect in patients with a low number of intra-tumoral IL-17⁺ non-T cells was significant with regard to disease-specific (p = 0.033) and disease-free survival (p = 0.012). This suggests that a high frequency of IL-17⁺ non-T cells was related to a poor immune response, which was further supported by the observation that a high number of T cells was correlated with improved disease-free survival in the HPV-positive OPSCC (p = 0.008). In addition, we detected a minor Th17 cell population. However, T cells obtained from HPV-positive OPSCC produced significantly more IL-17 than those from HPV-negative tumors (p = 0.006). The improved prognosis of HPV-positive OPSCC is thus correlated with higher numbers of tumor-infiltrating T cells, more active Th17 cells and lower numbers of IL-17⁺ non-T cells.

A phase I trial combining carboplatin/doxorubicin with tocilizumab, an anti-IL-6R monoclonal antibody, and interferon-α2b in patients with recurrent epithelial ovarian cancer

BACKGROUND

The immune system is important in epithelial ovarian cancer (EOC). Interleukin-6 is associated with chemoresistance and an immune-suppressive tumor microenvironment. We investigated whether a combination of chemotherapeutics, blockade of interleukin 6 (IL-6) receptor (IL-6R; tocilizumab), and immune enhancer interferon-α (Peg-Intron) is feasible, safe, and able to enhance immunity in patients with recurrent EOC.

PATIENTS AND METHODS

In this dose-escalation study, patients received tocilizumab 1, 2, 4, or 8 mg/kg i.v., q4 weeks during the first three cycles of carboplatin (AUC5) plus doxorubicin [pegylated liposomal doxorubicin (PLD) 30 mg/m(2) or doxorubicin 50 mg/m(2) i.v., day 1, q4 weeks, for six cycles]. At the highest tocilizumab dose (8 mg/kg), Peg-Intron (1 µg/kg s.c.) was added. Peripheral blood mononuclear cells were collected for immunomonitoring at baseline, after three and six cycles. Dose-limiting toxicity (DLT), CA-125, and radiologic response were evaluated.

RESULTS

In the 23 patients enrolled, no DLT was established. The most frequent grade 3/4 adverse events (CTCAE v4.03) were neutropenia (23%), febrile neutropenia (19%), and ileus (19%). No treatment-related deaths occurred. Using CT evaluation, 11 of 21 assessable patients responded, 6 had stable disease and 3 progressive disease. Patients receiving highest dose tocilizumab showed a functional blockade of IL-6R with increased levels of serum IL-6 (P = 0.02) and soluble IL-6R (P = 0.008). Consequently, immune cells displayed decreased levels of pSTAT3, myeloid cells produced more IL-12 and IL-1β while T cells were more activated and secreted higher amounts of effector cytokines interferon-γ and tumor necrosis factor-α. An increase in sIL-6R was potentially associated with a survival benefit (P = 0.03).

CONCLUSIONS

Functional IL-6R blocking is feasible and safe in EOC patients treated with carboplatin/(pegylated liposomal)doxorubicin, using 8 mg/kg tocilizumab. This combination is recommended for phase II evaluation based on immune parameters.

CLINICAL TRIAL REGISTER

NCT01637532.

The interferon-related developmental regulator 1 is used by human papillomavirus to suppress NFκB activation

High-risk human papillomaviruses (hrHPVs) infect keratinocytes and successfully evade host immunity despite the fact that keratinocytes are well equipped to respond to innate and adaptive immune signals. Using non-infected and freshly established or persistent hrHPV-infected keratinocytes we show that hrHPV impairs the acetylation of NFκB/RelA K310 in keratinocytes. As a consequence, keratinocytes display a decreased pro-inflammatory cytokine production and immune cell attraction in response to stimuli of the innate or adaptive immune pathways. HPV accomplishes this by augmenting the expression of interferon-related developmental regulator 1 (IFRD1) in an EGFR-dependent manner. Restoration of NFκB/RelA acetylation by IFRD1 shRNA, cetuximab treatment or the HDAC1/3 inhibitor entinostat increases basal and induced cytokine expression. Similar observations are made in IFRD1-overexpressing HPV-induced cancer cells. Thus, our study reveals an EGFR–IFRD1-mediated viral immune evasion mechanism, which can also be exploited by cancer cells.

Human papillomavirus employs immune evasion strategies to establish a long-term infection. Here the authors show that the virus in the EGFR-dependent manner induces IFRD1, which blocks NFκB activating acetylation, and that this process can be suppressed by the EGFR inhibitor cetuximab.

Tumor-infiltrating CD14-positive myeloid cells and CD8-positive T-cells prolong survival in patients with cervical carcinoma

One of the hallmarks of cancer is the influx of myeloid cells. In our study, we investigated the constitution of tumor-infiltrating myeloid cells and their relationship to other tumor-infiltrating immune cells, tumor characteristics and the disease-specific survival of patients with cervical cancer (CxCa). Triple-color immunofluorescence confocal microscopy was used to locate, identify and quantify macrophages (CD14), their maturation status (CD33) and their polarization (CD163) in a cohort of 86 patients with cervical carcinoma. Quantification of the numbers of myeloid cells revealed that a strong intraepithelial infiltration of CD14+ cells, and more specifically the population of CD14+CD33-CD163- matured M1 macrophages, is associated with a large influx of intraepithelial T lymphocytes (p = 0.008), improved disease-specific survival (p = 0.007) and forms an independent prognostic factor for survival (p = 0.033). The intraepithelial CD8+ T-cell and regulatory T-cell (Treg) ratio also forms an independent prognostic factor (p = 0.010) and combination of these two factors reveals a further increased benefit in survival for patients whose tumor displays a dense infiltration with intraepithelial matured M1 macrophages and a high CD8 T-cell/Treg ratio, indicating that both populations of immune cells simultaneously improve survival. Subsequently, we made a heatmap including all known immune parameters for these patients, whereby we were able to identify different immune signatures in CxCa. These results indicate that reinforcement and activation of the intratumoral M1 macrophages may form an attractive immunotherapeutic option in CxCa.

Chemotherapy alters monocyte differentiation to favor generation of cancer-supporting M2 macrophages in the tumor microenvironment

Current therapy of gynecologic malignancies consists of platinum-containing chemotherapy. Resistance to therapy is associated with increased levels of interleukin (IL)-6 and prostaglandin E2 (PGE(2)), 2 inflammatory mediators known to skew differentiation of monocytes to tumor-promoting M2 macrophages. We investigated the impact of cisplatin and carboplatin on 10 different cervical and ovarian cancer cell lines as well as on the ability of the tumor cells to affect the differentiation and function of cocultured monocytes in vitro. Treatment with cisplatin or carboplatin increased the potency of tumor cell lines to induce IL-10-producing M2 macrophages, which displayed increased levels of activated STAT3 due to tumor-produced IL-6 as well as decreased levels of activated STAT1 and STAT6 related to the PGE(2) production of tumor cells. Blockade of canonical NF-κB signaling showed that the effect of the chemotherapy was abrogated, preventing the subsequent increased production of PGE(2) and/or IL-6 by the tumor cell lines. Treatment with the COX-inhibitor indomethacin and/or the clinical monoclonal antibody against interleukin-6 receptor (IL-6R), tocilizumab, prevented M2-differentiation. Importantly, no correlation existed between the production of PGE(2) or IL-6 by cancer cells and their resistance to chemotherapy-induced cell death, indicating that other mechanisms underlie the reported chemoresistance of tumors producing these factors. Our data suggest that a chemotherapy-mediated increase in tumor-promoting M2 macrophages may form an indirect mechanism for chemoresistance. Hence, concomitant therapy with COX inhibitors and/or IL-6R antibodies might increase the clinical effect of platinum-based chemotherapy in otherwise resistant tumors.

An unexpectedly large polyclonal repertoire of HPV-specific T cells is poised for action in patients with cervical cancer

The diversity and extent of the local tumor-specific T-cell response in a given individual is largely unknown. We have performed an in-depth study of the local T-cell repertoire in a selected group of patients with cervical cancer, by systematic analyses of the proportion, breadth, and polarization of human papillomavirus (HPV) E6/E7-specific T cells within the total population of tumor-infiltrating lymphocytes (TIL) and tumor-draining lymph node cells (TDLNC). Isolated T cells were stimulated with sets of overlapping E6 and E7 peptides and analyzed by multiparameter flow cytometry with respect to activation, cytokine production, and T-cell receptor Vbeta usage. HPV-specific CD4+ and CD8+ T-cell responses were detected in TIL and TDLNC and their relative contribution varied between <1% and 66% of all T cells. In general, these HPV-specific responses were surprisingly broad, aimed at multiple E6 and E7 epitopes and involved multiple dominant and subdominant T-cell receptor Vbetas per single peptide-epitope. In most patients, only few IFNgamma-producing T cells were found and the amount of IFNgamma produced was low, suggesting that these are poised T cells, rendered functionally inactive within the tumor environment. Importantly, stimulation of the TIL and TDLNC with cognate antigen in the presence of commonly used Toll-like receptor ligands significantly enhanced the effector T-cell function. In conclusion, our study suggests that within a given patient with HPV-specific immunity many different tumor-specific CD4+ and CD8+ T cells are locally present and poised for action. This vast existing local T-cell population is awaiting proper stimulation and can be exploited for the immunotherapy of cancer.

Hsp70 expression and induction as a readout for detection of immune modulatory components in food

Stress proteins such as heat shock proteins (Hsps) are up-regulated in cells in response to various forms of stress, like thermal and oxidative stress and inflammation. Hsps prevent cellular damage and increase immunoregulation by the activation of anti-inflammatory T-cells. Decreased capacity for stress-induced Hsp expression is associated with immune disorders. Thus, therapeutic boosting Hsp expression might restore or enhance cellular stress resistance and immunoregulation. Especially food- or herb-derived phytonutrients may be attractive compounds to restore optimal Hsp expression in response to stress. In the present study, we explored three readout systems to monitor Hsp70 expression in a manner relevant for the immune system and evaluated novel Hsp co-inducers. First, intracellular staining and analysis by flow cytometry was used to detect stress and/or dietary compound induced Hsp70 expression in multiple rodent cell types efficiently. This system was used to screen a panel of food-derived extracts with potent anti-oxidant capacity. This strategy yielded the identity of several new enhancers of stress-induced Hsp70 expression, among them carvacrol, found in thyme and oregano. Second, CD4(+) T-cell hybridomas were generated that specifically recognized an immunodominant Hsp70 peptide. These hybridomas were used to show that carvacrol enhanced Hsp70 levels increased T-cell activation. Third, we generated a DNAJB1-luc-O23 reporter cell line to show that carvacrol increased the transcriptional activation of a heat shock promoter in the presence of arsenite. These assay systems are generally applicable to identify compounds that affect the Hsp level in cells of the immune system.