Induction of Immunological Antitumor Effects by the Combination of Adenovirus-Mediated Gene Transfer of B7-1 and Anti-Programmed Cell Death-1 Antibody in a Murine Squamous Cell Carcinoma Model

BACKGROUND

The goal of this study was to evaluate the antitumor immune effects of B7-1 gene expression in addition to immune checkpoint inhibitor against squamous cell carcinoma.

METHODS

A murine SCC cell line, KLN205, was infected with adenoviral vector carrying B7-1 (AdB7). Infected cells were injected subcutaneously in the flanks of DBA/2 mice. Three weeks after implantation, anti-mouse PD-1 antibody (antiPD1) was intraperitonially administrated twice a week for a total of six times.

RESULTS

CD80 was significantly overexpressed in the AdB7-infected tumors. IFN-gamma in the T cells in the spleen was significantly increased and tumor size was significantly reduced in the mice treated with both AdB7 and antiPD1. Targeted tumors treated with both AdB7 and antiPD1 exhibited significantly increased cell densities of total immune cells as well as Ki-67+ CD8+ T cells and decreased regulatory T cells.

CONCLUSIONS

These results suggest that the B7-1 gene transfer may enhance the antitumor effect of anti-PD1 antibody against SCC.

Extent of thyroidectomy and paratracheal lymph node dissection in total pharyngolaryngectomy for pyriform sinus cancer, and recurrence, survival, and postoperative hypoparathyroidism: A multicenter retrospective study

BACKGROUND

Total pharyngolaryngectomy (TPL) is standard treatment for hypopharyngeal cancer. However, extensive thyroidectomy and paratracheal nodal dissection (PTND) can cause hypoparathyroidism. We sought to determine the optimum extent of resection.

METHODS

We analyzed the clinicopathological information of 161 pyriform sinus cancer patients undergoing TPL from 25 Japanese institutions. Rates of recurrence and risk factors for hypoparathyroidism, as well as incidence of pathological contralateral level VI nodal metastasis and stomal recurrence, were investigated.

RESULTS

The extent of thyroidectomy and nodal dissection were not independent risk factors for recurrence. Incidences of contralateral level VI nodal involvement and stomal recurrence were 1.8% and 1.2%, respectively. Patients undergoing hemithyroidectomy/ipsilateral PTND did not develop stomal recurrence and had the lowest incidence of hypoparathyroidism. Prognosis in patients without tracheostomy prior to hemithyroidectomy/ipsilateral PTND was comparable to that with more extensive resections.

CONCLUSIONS

Hemithyroidectomy/ipsilateral PTND may be sufficient for pyriform sinus cancer cases without tracheostomy.

Quantitative multiplex immunohistochemistry reveals inter-patient lymphovascular and immune heterogeneity in primary cutaneous melanoma

Introduction

Quantitative, multiplexed imaging is revealing complex spatial relationships between phenotypically diverse tumor infiltrating leukocyte populations and their prognostic implications. The underlying mechanisms and tissue structures that determine leukocyte distribution within and around tumor nests, however, remain poorly understood. While presumed players in metastatic dissemination, new preclinical data demonstrates that blood and lymphatic vessels (lymphovasculature) also dictate leukocyte trafficking within tumor microenvironments and thereby impact anti-tumor immunity. Here we interrogate these relationships in primary human cutaneous melanoma.

Methods

We established a quantitative, multiplexed imaging platform to simultaneously detect immune infiltrates and tumor-associated vessels in formalin-fixed paraffin embedded patient samples. We performed a discovery, retrospective analysis of 28 treatment-naïve, primary cutaneous melanomas.

Results

Here we find that the lymphvasculature and immune infiltrate is heterogenous across patients in treatment naïve, primary melanoma. We categorized five lymphovascular subtypes that differ by functionality and morphology and mapped their localization in and around primary tumors. Interestingly, the localization of specific vessel subtypes, but not overall vessel density, significantly associated with the presence of lymphoid aggregates, regional progression, and intratumoral T cell infiltrates.

Discussion

We describe a quantitative platform to enable simultaneous lymphovascular and immune infiltrate analysis and map their spatial relationships in primary melanoma. Our data indicate that tumor-associated vessels exist in different states and that their localization may determine potential for metastasis or immune infiltration. This platform will support future efforts to map tumor-associated lymphovascular evolution across stage, assess its prognostic value, and stratify patients for adjuvant therapy.

Abstract 4453: Neutrophil-to-lymphocyte ratio associates with intratumoral myeloid predominance and clinical outcomes of pembrolizumab in head and neck squamous cell carcinoma

Neutrophil-to-lymphocyte ratio (NLR) in peripheral blood is an emerging biomarker candidate of immunotherapy in a wide range of cancers. However, little is known about the potential relationships between the tumor immune microenvironment and systemic inflammatory markers including NLR. Here we have explored systemic and tumor-immune microenvironmental characteristics related to treatment outcomes of immune checkpoint inhibition, based on 29 consecutive patients with recurrent/metastatic head and neck squamous cell carcinoma who received pembrolizumab between 2020 and 2021. NLR greater than 4.5 at pretreatment status significantly correlated with short overall survival (OS). Although NLR did not show a significant association with tumor volumes, high NLR exhibited significant correlations with malnutrition status characterized by CONUT (controlling nutritional status), and GNRI (geriatric nutrition risk index). Among the patients whose NLR was greater than 4.5 at pretreatment status, those whose NLR decreased to less than 4.5 at day 21 had a better OS than those whose NLR did not decrease, indicating that longitudinal changes in NLR correlate with prognosis. To investigate association with tumor-immune microenvironment, 14-marker multiplex immunohistochemistry was performed to quantitatively evaluate intratumoral CD8+ T cells, helper T cells, regulatory T cells, B cells, natural killer cells, macrophages, dendritic cells, mast cells, and granulocytes. Notably, NLR at pretreatment status significantly correlated with intratumoral immune cell densities, where high NLR correlated with low lymphoid cells and high tumor associated macrophages in tissue. NLR in peripheral blood significantly correlated with myeloid to lymphoid cell ratios in tissue, suggesting the presence of association between circulating and intratumoral immune complexity profiles. This study highlights that the association between intratumoral myeloid predominance and systemic nutritional and inflammatory status might be a possible factor for resistance to immunotherapy. Understanding immune dynamics in tissue and blood during immunotherapy potentially contributes to the establishment of predictive biomarkers and monitoring for immunotherapy.

Citation Format: Hiroki Morimoto, Takahiro Tsujikawa, Aya Miyagawa-Hayashino, Alisa Kimura, Sumiyo Saburi, Junichi Mitsuda, Kanako Yoshimura, Gaku Ohmura, Shigeyuki Mukudai, Hikaru Nagao, Yoichiro Sugiyama, Shibata Saya, Hiroshi Ogi, Eiichi Konishi, Kyoko Itoh, Shigeru Hirano. Neutrophil-to-lymphocyte ratio associates with intratumoral myeloid predominance and clinical outcomes of pembrolizumab in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4453.

Abstract 5172: Tumor-immune microenvironmental profiling during chemo- and targeted therapy for head and neck squamous cell carcinoma

Understanding longitudinal changes of tumor-immune microenvironment during chemo/targeted therapies contributes to the development of optimized combinations of immunotherapy with chemotherapy and targeted therapy for patients with head and neck squamous cell carcinoma (HNSCC). We previously reported a chromogenic sequential immunohistochemical (IHC) platform enabling quantitative and spatial assessment of 29+ biomarkers in a single tissue section (Tsujikawa T et al. Cell Reports 2017, Banik G et al. Methods Enzymology 2020). Using this platform, densities, phenotypes, and distributions of tumor and immune cells were evaluated, comparing baseline and post-treatment specimens from the same individual treated by paclitaxel, carboplatin, and cetuximab (PCE) for advanced HNSCC (N = 30). Immune cell density analyses based on CD8+ T cells, helper T cells, regulatory T cells, B cells, natural killer cells, macrophages, dendritic cells, mast cells, granulocytes revealed the presence of differential immune cell compositions, where immune profiles were divided into hypo-, lymphoid-, and myeloid-inflamed groups according to the same criteria as in our previous report (Tsujikawa et al. Cell Reports 2017). Lymphoid and hypo-inflamed groups exhibited significant tumor volume reduction, increased CD45+ immune cell densities and elevated combined positive scores of PD-L1 at the post-treatment status, suggesting the potential involvement of immunogenic mechanisms related to therapeutic response. On the other hand, the myeloid group exhibited no significant tumor volume reduction, together with higher expression of HIF1α and ZEB2 on tumor cells which are potentially associated with hypoxia and epithelial-mesenchymal transition. In conclusion, longitudinal tissue-based monitoring revealed the presence of differential tumor-immune complexity profiles related to therapeutic efficacy and resistance. Hypo-inflamed profiles might require upfront chemo/targeted therapy before immunotherapy, and myeloid-inflamed profiles might require myeloid cell-targeted therapies, mandating the establishment of rapid clinical assessment of tumor-immune microenvironment.

Citation Format: Alisa Kimura, Takahiro Tsujikawa, Junichi Mitsuda, Aya Miyagawa-Hayashino, Hiroki Morimoto, Sumiyo Saburi, Kanako Yoshimura, Gaku Ohmura, Sigeyuki Mukudai, Hikaru Nagao, Yoichiro Sugiyama, Hiroshi Ogi, Saya Shibata, Eiichi Konishi, Kyoko Itoh, Shigeru Hirano. Tumor-immune microenvironmental profiling during chemo- and targeted therapy for head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5172.

Mechanisms of primary and acquired resistance to immune checkpoint inhibitors in advanced non-small cell lung cancer: A multiplex immunohistochemistry-based single-cell analysis

OBJECTIVE

Immune checkpoint inhibitors (ICIs) have become a key therapeutic modality for advanced non-small cell lung cancer (NSCLC), but most patients experience primary or acquired resistance to these drugs. We here explored the mechanisms underlying both types of ICI resistance by analysis of the tumor immune microenvironment (TME).

MATERIALS AND METHODS

Four patients who experienced a long-term response to ICI treatment (progression-free survival [PFS] of ≥12 months) followed by disease progression, after which a rebiopsy was immediately performed (cohort-A), as well as four patients who experienced early tumor progression during ICI treatment (PFS of <9 weeks, cohort-B) were enrolled in this retrospective study. The pretreatment TME was evaluated by 16- or 17-color multiplex immunohistochemistry (mIHC)-based spatial profiling at the single-cell level for both cohorts. In cohort-A, changes in the TME after disease progression during ICI treatment were also investigated by mIHC analysis and transcriptomic analysis.

RESULTS

Pretreatment tumor tissue from cohort-B manifested poor infiltration of tumor-reactive CD8⁺ T cells characterized by CD39 and CD103 expression or by programmed cell death-1 expression, implicating insufficient recognition of tumor cells by CD8⁺ T cells as a mechanism of primary ICI resistance. Analysis of the paired tumor specimens from cohort-A revealed various changes in the TME associated with acquired ICI resistance, including substantial infiltration of myeloid-derived suppressor cells and M2-type tumor-associated macrophages without a marked decline in the number of tumor-reactive CD8⁺ T cells; a decrease in the number of tumor-reactive CD8⁺ T cells; and an apparent decrease in neoantigen presentation by tumor cells.

CONCLUSION

The presence of intratumoral tumor-reactive CD8⁺ T cells may be a prerequisite for a long-term response to ICI treatment in advanced NSCLC, but it is not sufficient for cancer cell eradication. Various TME profiles are associated with acquired ICI resistance, suggesting that patient-specific strategies to overcome such resistance may be necessary.

Multiplex immunohistochemistry reveals cochlear macrophage heterogeneity and local auditory nerve inflammation in cisplatin-induced hearing loss

Inner ear macrophages play a vital role in cochlear homeostasis. Recent studies have demonstrated the existence of macrophages at different sites of the cochlea, with increased cochlear infiltration as an inflammatory response mechanism to injury. However, current methods, such as conventional immunohistochemistry and flow cytometry, provide limited information about the diversity of cochlear macrophages. Recently, multiplex immunohistochemistry (mIHC) successfully identified the heterogeneity of immune cells in cancer tissue and thereby improved our understanding of the disease prognosis. In this study, we modified the mIHC technique for cochlear tissue and utilized it to investigate cochlear macrophage behavior and heterogeneity before and after exposure to ototoxic drugs such as cisplatin. Four-week-old C57BL/6N female mice were intraperitoneally injected with cisplatin at 5 mg/kg/day consecutively for 6 days. Their hearing levels were assessed before and after the injection. Their cochleae were harvested before (day 0) and on days 8 and 15 after the cisplatin injection. Paraffin-embedded sections were sequentially immunostained using macrophage surface markers to identify the different categories of macrophages. Each immunostaining cycle included incubation with primary antibody, incubation with secondary antibody, chromogenic staining, and image scanning. Thereafter, all antibodies were stripped out, and antigen retrieval was performed to prepare the tissue for the next cycle. The results revealed that activated cochlear macrophages were not entirely differentiated into M1 or M2 categories but into multi-marker M1/M2 mixed macrophages. Furthermore, the ratio of these mixed (M1/M2) macrophages to Iba1+ macrophages increased in the auditory nerve after cisplatin exposure, suggesting local auditory nerve inflammation. The increase in the population of activated macrophages in the auditory nerve region was concomitant with the temporary shift of hearing threshold on day 8 post-cisplatin injection. The findings of this study indicate the effectiveness of mIHC in identifying cochlear macrophage heterogeneity both in the resting state and after cisplatin exposure. Therefore, mIHC could be a powerful tool in cochlear immunology research. Our findings may provide new insights into the co-relation between the cochlear macrophage and cisplatin exposure.

Contribution of MMP14-expressing cancer-associated fibroblasts in the tumor immune microenvironment to progression of colorectal cancer

Matrix metalloproteinase 14 (MMP14) expression is implicated in progression of colorectal cancer, but its role in the tumor microenvironment (TME) has been unclear. The relevance of MMP14 to colorectal cancer progression was explored by analysis of transcriptomic data for colorectal adenocarcinoma patients (n = 592) in The Cancer Genome Atlas. The role of MMP14 in the TME was investigated in a retrospective analysis of tumor samples from 86 individuals with stage III colorectal cancer by single cell–based spatial profiling of MMP14 expression as performed by 12-color multiplex immunohistochemistry (mIHC). Analysis of gene expression data revealed that high MMP14 expression was associated with tumor progression and implicated both cancer-associated fibroblasts (CAFs) and tumor-associated macrophages in such progression. Spatial profiling by mIHC revealed that a higher percentage of MMP14⁺ cells among intratumoral CAFs (MMP14⁺ CAF/CAF ratio) was associated with poorer relapse-free survival. Multivariable analysis including key clinical factors identified the MMP14⁺ CAF/CAF ratio as an independent poor prognostic factor. Moreover, the patient subset with both a high MMP14⁺ CAF/CAF ratio and a low tumor-infiltrating lymphocyte density showed the worst prognosis. Our results suggest that MMP14⁺ CAFs play an important role in progression of stage III colorectal cancer and may therefore be a promising therapeutic target.

Genomic and immune microenvironment profiling in a case of metastatic intrathyroid thymic carcinoma

Metastatic intrathyroid thymic carcinoma (ITTC) is a rare cancer with no effective drugs for controlling. This case report has shown genomic and immune microenvironment profiles in metastatic ITTC and emphasized an immunosuppression via a PD‐1/PD‐L1 pathway, possibly strengthening the rationale for immune checkpoint blockade as a novel treatment.

Abstract 5210: Tumor immune characterization identifies age-stratified biomarkers for nivolumab in patients with head and neck squamous cell carcinoma: A nationwide collaborative study in Japan

Background: Biomarkers predicting therapeutic response to immunotherapy have been widely explored via monitoring the liquid and tissue-derived components. Increasing treatment options for recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) mandates prediction of the therapeutic response of anti-PD-1 antibody alone as well as optimization of the treatment sequence. In view of improving biomarkers predicting the efficacy of immunotherapy for R/M HNSCC, we hypothesized that biomarkers can be personalized depending on clinicopathological backgrounds and treatment sequence.

Methods: In this study, we retrospectively included formalin-fixed paraffin-embedded (FFPE) samples, peripheral blood cell counts at treatment, clinicopathological information, and outcome data for patients with R/M HNSCC receiving nivolumab across 22 institutions in Japan (N = 100). FFPE samples were subjected to 14-marker multiplex immunohistochemistry (IHC) and image cytometry analysis (Tsujikawa T et al. Cell Reports, 2017) to quantitatively evaluate CD8+ T cells, helper T cells, regulatory T cells, B cells, natural killer (NK) cells, macrophages, dendritic cells, CD66b+ granulocytes, mast cells, programmed death ligand 1 (PD-L1) and PD-1 expression in a single slide. Intratumoral and circulating immune cell frequencies were comparatively analyzed between responders (CR, n = 14; PR, n = 39) and non-responders (SD, n = 2; PD, n = 45).

Results: Of 100 patients included, responders had significantly lower smoking and alcohol index, higher incidence of immune related adverse events, and higher PD-L1 expression in immune cells as well as PD-L1 combined positive score (CPS) than non-responders. Next, focusing on the history of prior therapy, stratified analysis revealed that the frequency of NK cells was associated with nivolumab response in patients with prior cetuximab use, but not in cetuximab-naïve status. Furthermore, stratified analysis by patient age revealed that nivolumab response was significantly associated with high CPS and lymphoid-inflamed profiles based on cell densities of nine immune cell lineages in the group aged 65 years or older, but not in the group under 65 years of age. On the contrary, the neutrophil/lymphocyte ratios (NLR) in peripheral blood counts at nivolumab treatment were significantly lower in responders (mean 4.96) than those in non-responders (mean 10.46) in the group under 65 years of age, but not in those over 65 years of age (7.41 versus 8.47).

Conclusions: Using peripheral blood data and tumor tissue profiling stratified by patient age and prior treatment might provide better predictive biomarkers in nivolumab response to HNSCC. Further preclinical and clinical studies elucidating immune mechanisms in different patient backgrounds will be warranted.

Citation Format: Takahiro Tsujikawa, Kazuchika Ohno, Sumiyo Saburi, Junichi Mitsuda, Kanako Yoshimura, Alisa Kimura, Hiroki Morimoto, Gaku Ohmura, Akihito Arai, Hiroshi Ogi, Saya Shibata, Yosuke Ariizumi, Akihisa Tasaki, Ryosuke Takahashi, Yumiko Tateishi, Hiroaki Kawabe, Sadakatsu Ikeda, Kei-ichi Morita, Tatsuhiko Tsunoda, Takumi Akashi, Morito Kurata, Issei Imoto, Yasushi Shimizu, Akihito Watanabe, Yukinori Asada, Ryuichi Hayashi, Yuki Saito, Hiroyuki Ozawa, Kiyoaki Tsukahara, Nobuhiko Oridate, Arata Horii, Takashi Maruo, Nobuhiro Hanai, Hidenori Inohara, Hiroshi Iwai, Takashi Fujii, Ken-ichi Nibu, Shigemichi Iwae, Tsutomu Ueda, Ryuji Yasumatsu, Hirohito Umeno, Muneyuki Masuda, Kyoko Itoh, Shigeru Hirano, Takahiro Asakage. Tumor immune characterization identifies age-stratified biomarkers for nivolumab in patients with head and neck squamous cell carcinoma: A nationwide collaborative study in Japan [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5210.

Spatially resolved immune microenvironmental profiling for follicular thyroid carcinoma with minimal capsular invasion

Spatial profiles of the tumor-immune microenvironment are associated with disease progression and clinicopathological factors in various cancers. Follicular thyroid carcinoma (FTC) is the second most common thyroid cancer, where the presence of capsular invasion or angioinvasion determines the pathological diagnosis; however, little is known about the immune microenvironment profiles associated with the acquisition of invasive potential of FTC. In this study, we focused on FTC with minimal capsular invasion, and the spatially resolved immune microenvironment of FTC was studied in the discovery (n = 13) and validation cohorts (n = 40). CD8⁺ T cells, helper T cells, regulatory T cells, B cells, natural killer cells, tumor-associated macrophages, CD66⁺ granulocytes, mature dendritic cells, and mast cells were quantitatively evaluated in single tissue sections, via a 12-marker multiplex immunohistochemistry and image cytometry. Cell densities and compositions of immune cells were spatially stratified by six tissue regions including tumor center, subcapsular region, capsular invasion, adjacent stroma of capsular invasion, peritumoral stroma, and adjacent normal. Lymphoid cell lineages in the tumor center and subcapsular regions were significantly lower than those in adjacent normal and peritumoral stroma, potentially related to the lymphoid lineage exclusion from the intratumoral regions of FTC. Interestingly, immune cell composition profiles in the capsular invasive front were distinct from those of intratumoral region. The ratios of T cells to CD66b⁺ granulocytes with capsular invasion were significantly higher than those without capsular invasion, suggesting the presence of a unique immune microenvironment at the invasive front between tumor foci and stroma. In addition, tumor cells at the capsular invasive front showed significantly higher expression of tumor programmed cell death ligand 1 (PD-L1) than those at the tumor center. This study revealed spatial immune profiles associated with capsular invasion of FTC, providing new insights into the mechanisms underlying its development and initial invasion.

Role of necroptosis of alveolar macrophages in acute lung inflammation of mice exposed to titanium dioxide nanoparticles

Titanium dioxide (TiO₂) nanoparticles are indispensable for daily life but induce acute inflammation, mainly via inhalation exposure. TiO₂ nanoparticles can be phagocytosed by alveolar macrophages (AMs) in vivo and cause necroptosis of exposed cells in vitro. However, the relationship between localization of TiO₂ nanoparticles in the lungs after exposure and their biological responses including cell death and inflammation remains unclear. This study was conducted to investigate the intra/extracellular localization of TiO₂ nanoparticles in murine lungs at 24 h after intratracheal exposure to rutile TiO₂ nanoparticles and subsequent local biological reactions, specifically necroptosis of AMs and lung inflammation. We found that TiO₂ exposure induced leukocyte migration into the alveolar region and increased the secretion of C-C motif ligand (CCL) 3 in the bronchoalveolar lavage (BAL) fluid. A combination of Raman spectroscopy and staining of cell and tissue samples confirmed that AMs phagocytose TiO₂. AMs that phagocytosed TiO₂ nanoparticles showed necroptosis, characterized by the expression of phosphorylated mixed lineage kinase domain-like protein and translocation of high mobility group box-1 from the cell nucleus to the cytoplasm. In primary cultured AMs, TiO₂ also induced necroptosis and increased the secretion of CCL3. Necroptosis inhibitors suppressed the increase in CCL3 secretion in both the BAL fluid and culture supernatant of AMs and suppressed the increase in leukocytes in the BAL fluid. These data suggest that necroptosis of AMs that phagocytose TiO₂ nanoparticles is involved as part of the mechanism by which TiO₂ induces acute lung inflammation.

Extracellular acidity in tumor tissue upregulates programmed cell death protein 1 expression on tumor cells via proton-sensing G protein-coupled receptors

Acidity in the tumor microenvironment has been reported to promote cancer growth and metastasis. In our study, we examined a potential relation between extracellular acidity and expression level of the immune checkpoint molecule programmed cell death protein 1 (PD-L1) in murine squamous cell carcinoma (SCC) and melanoma cell lines. PD-L1 expression in the tumor cells was upregulated by culturing in a low pH culture medium. Tumor-bearing mice were allowed to ingest sodium bicarbonate, resulting in neutralization of acidity in the tumor tissue, a decrease in PD-L1 expression in tumor cells and suppression of tumor growth in vivo. Proton-sensing G protein-coupled receptors, T-cell death-associated gene 8 (TDAG8) and ovarian cancer G-protein-coupled receptor 1 (OGR1), were upregulated by low pH, and essentially involved in the acidity-induced elevation of PD-L1 expression in the tumor cells. Human head and neck SCC RNAseq data from the Cancer Genome Atlas also suggested a statistically significant correlation between expression levels of the proton sensors and PD-L1 mRNA expression. These findings strongly suggest that neutralization of acidity in tumor tissue may result in reduction of PD-L1 expression, potentially leading to inhibition of an immune checkpoint and augmentation of antitumor immunity.

Spatial Profiles of Intratumoral PD-1+ Helper T Cells Predict Prognosis in Head and Neck Squamous Cell Carcinoma

Background

Functional interactions between immune cells and neoplastic cells in the tumor immune microenvironment have been actively pursued for both biomarker discovery for patient stratification, as well as therapeutic anti-cancer targets to improve clinical outcomes. Although accumulating evidence indicates that intratumoral infiltration of immune cells has prognostic significance, limited information is available on the spatial infiltration patterns of immune cells within intratumoral regions. This study aimed to understand the intratumoral heterogeneity and spatial distribution of immune cell infiltrates associated with cell phenotypes and prognosis in head and neck squamous cell carcinoma (HNSCC).

Methods

A total of 88 specimens of oropharyngeal squamous cell carcinoma, categorized into discovery (n = 38) and validation cohorts (n = 51), were analyzed for immune contexture by multiplexed immunohistochemistry (IHC) and image cytometry-based quantification. Tissue segmentation was performed according to a mathematical morphological approach using neoplastic cell IHC images to dissect intratumoral regions into tumor cell nests versus intratumoral stroma.

Results

Tissue segmentation revealed heterogeneity in intratumoral T cells, varying from tumor cell nest-polarized to intratumoral stroma-polarized distributions. Leukocyte composition analysis revealed higher ratios of TH1/TH2 in tumor cell nests with higher percentages of helper T cells, B cells, and CD66b+ granulocytes within intratumoral stroma. A discovery and validation approach revealed a high density of programmed death receptor-1 (PD-1)+ helper T cells in tumor cell nests as a negative prognostic factor for short overall survival. CD163+ tumor-associated macrophages (TAM) provided the strongest correlation with PD-1+ helper T cells, and cases with a high density of PD-1+ helper T cells and CD163+ TAM had a significantly shorter overall survival than other cases.

Conclusion

This study reveals the significance of analyzing intratumoral cell nests and reports that an immune microenvironment with a high density of PD-1+ helper T cells in tumoral cell nests is a poor prognostic factor for HNSCC.

A 14-Marker Multiplexed Imaging Panel for Prognostic Biomarkers and Tumor Heterogeneity in Head and Neck Squamous Cell Carcinoma

Recent advances made in treatment for head and neck squamous cell carcinoma (HNSCC) highlight the need for new prediction tools to guide therapeutic strategies. In this study, we aimed to develop a HNSCC-targeting multiplex immunohistochemical (IHC) panel that can evaluate prognostic factors and the intratumor heterogeneity of HNSCC. To identify IHC-based tissue biomarkers that constitute new multiplex IHC panel, a systematic review and meta-analysis were performed to analyze reported IHC biomarkers in laryngeal and pharyngeal SCC in the period of 2008–2018. The Cancer Genome Atlas (TCGA) and Reactome pathway databases were used to validate the prognostic and functional significance of the identified biomarkers. A 14-marker chromogenic multiplex IHC panel including identified biomarkers was used to analyze untreated HNSCC tissue. Forty-five high-quality studies and thirty-one candidate tissue biomarkers were identified (N = 7062). Prognostic validation in TCGA laryngeal and pharyngeal SCC cohort (N = 205) showed that β-catenin, DKK1, PINCH1, ADAM10, and TIMP1 were significantly associated with poor prognosis, which were related to functional categories such as immune system, cellular response, cell cycle, and developmental systems. Selected biomarkers were assembled to build a 14-marker panel, evaluating heterogeneity and polarized expression of tumor biomarkers in the tissue structures, which was particularly related to activation of Wnt/β-catenin pathway. Integrated IHC analysis based on a systemic review and meta-analysis provides an in situ proteomics tool to assess the aggressiveness and intratumor heterogeneity of HNSCC.

Exposure to particulate matter upregulates ACE2 and TMPRSS2 expression in the murine lung

Coronavirus disease (COVID-19) is currently a serious global issue. Epidemiological studies have identified air pollutants, including particulate matter (PM), as a risk factor for COVID-19 infection and severity of illness, in addition to numerous factors such as pre-existing conditions, aging and smoking. However, the mechanisms by which air pollution is involved in the manifestation and/or progression of COVID-19 is still unknown. In this study, we used a mouse model exposed to crude PM, collected by the cyclone method, to evaluate the pulmonary expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine type 2 (TMPRSS2), the two molecules required for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into host cells. Multiplex immunohistochemical analysis revealed that exposure to PM increased the expression of these two molecules at the same site. Furthermore, image cytometry analysis revealed increased expression of these proteins, particularly, in the alveolar type 2 cells and macrophages, which are potential targets for SARS-CoV-2. Our findings provide an experimental evidence that exposure to PM may adversely affect the manifestation and progression of COVID-19, mediated by the impact of SARS-CoV-2 on the site of entry. The study results suggest that examining these effects might help to advance our understanding of COVID-19 and aid the development of appropriate social interventions.

Prognostic significance of spatial immune profiles in human solid cancers

Immune-based tumor characteristics in the context of tumor heterogeneity are associated with suppression as well as promotion of cancer progression in various tumor types. As immunity typically functions based on intercellular contacts and short-distance cytokine communications, the location and spatial relationships of the tumor immune microenvironment can provide a framework to understand the biology and potential predictive biomarkers related to disease outcomes. Immune spatial analysis is a newly emerging form of cancer research based on recent methodological advances in in situ single-cell analysis, where cell-cell interaction and the tissue architecture can be analyzed in relation to phenotyping the tumor immune heterogeneity. Spatial characteristics of tumors can be stratified into the tissue architecture level and the single-cell level. At the tissue architecture level, the prognostic significance of the density of immune cell lineages, particularly T cells, is leveraged by understanding longitudinal changes in cell distribution in the tissue architecture such as intra-tumoral and peri-tumoral regions, and invasive margins. At the single-cell level, the proximity of the tumor to the immune cells correlates with disease aggressiveness and therapeutic resistance, providing evidence to understand biological interactions and characteristics of the tumor immune microenvironment. In this review, we summarize recent findings regarding spatial information of the tumor immune microenvironment and review advances and challenges in spatial single-cell analysis toward developing tissue-based biomarkers rooted in the immune spatial landscape.

Evaluation of Cyclophosphamide/GVAX Pancreas Followed by Listeria-Mesothelin (CRS-207) with or without Nivolumab in Patients with Pancreatic Cancer

PURPOSE

Two studies in previously treated metastatic pancreatic cancer have been completed combining GVAX pancreas vaccine (GM-CSF-secreting allogeneic pancreatic tumor cells) with cyclophosphamide (Cy) and CRS-207 (live, attenuated Listeria monocytogenes-expressing mesothelin). In the current study, we compared Cy/GVAX followed by CRS-207 with (Arm A) or without nivolumab (Arm B).

PATIENTS AND METHODS

Patients with pancreatic adenocarcinoma who received one prior therapy for metastatic disease and RECIST measurable disease were randomized 1:1 to receive treatment on Arm A or Arm B. The primary objective was to compare overall survival (OS) between the arms. Additional objectives included assessment of progression-free survival, safety, tumor responses, CA19-9 responses, and immunologic correlates.

RESULTS

Ninety-three patients were treated (Arm A, 51; Arm B, 42). The median OS in Arms A and B were 5.9 [95% confidence interval (CI), 4.7-8.6] and 6.1 (95% CI, 3.5-7.0) months, respectively, with an HR of 0.86 (95% CI, 0.55-1.34). Objective responses were seen in 3 patients using immune-related response criteria (4%, 2/51, Arm A; 2%, 1/42, Arm B). The grade ≥3 related adverse event rate, whereas higher in Arm A (35.3% vs. 11.9%) was manageable. Changes in the microenvironment, including increase in CD8+ T cells and a decrease in CD68+ myeloid cells, were observed in long-term survivors in Arm A only.

CONCLUSIONS

Although the study did not meet its primary endpoint of improvement in OS of Arm A over Arm B, the OS was comparable with standard therapy. Objective responses and immunologic changes in the tumor microenvironment were evident.

Neck dissection prolongs survival in patient with stage IVC hypopharyngeal carcinoma with mixed responses to nivolumab

Surgical intervention aids in maintaining quality of life in patients with recurrent metastatic head and neck carcinoma with mixed responses to nivolumab treatment. However, the mechanisms involved in these mixed responses remain unclear. Systemic chemotherapy using the EXTREME regimen was administered to the patient with hypopharyngeal carcinoma and liver metastases as well as cervical lymph node metastases. The patient was subsequently treated with nivolumab after developing signs of progressive disease. Although the hypopharyngeal tumors and liver metastases were well-controlled, cervical lymph node dissection was performed because of the enlargement of some of the lymph node metastases. Postoperative nivolumab administration was resumed, and this patient is presently alive and disease-free. Immediately after neck dissection, the LNs that responded and those that did not respond to nivolumab were separated and evaluated. The LNs that responded well to nivolumab presented with prominent interstitial fibrosis. Conversely, in LNs that enlarged after nivolumab, significant proliferation of the viable tumor cells and almost no degeneration or necrosis was observed. Additionally, we performed immunohistological assessments on pathologic samples of multiple lesions with differing responses to treatment. Targeted surgical intervention appears to be a valuable adjunct to treatment with nivolumab.

ADAP1 promotes invasive squamous cell carcinoma progression and predicts patient survival

ADAP1, a GTPase-activating protein (GAP) for the small GTPase ARF6, is a strong predictor of poor survival in early-stage squamous cell carcinoma patients and a critical mediator of TGF-β-induced invasive cell migration by facilitating basement membrane breakdown.

Invasive squamous cell carcinoma (SCC) is aggressive cancer with a high risk of recurrence and metastasis, but the critical determinants of its progression remain elusive. Here, we identify ADAP1, a GTPase-activating protein (GAP) for ARF6 up-regulated in TGF-β-responding invasive tumor cells, as a strong predictor of poor survival in early-stage SCC patients. Using a mouse model of SCC, we show that ADAP1 overexpression promotes invasive tumor progression by facilitating cell migration and breakdown of the basement membrane. We found that ADAP1-rich, TGF-β-responding tumor cells exhibit cytoplasmic laminin localization, which correlated with the absence of laminin and type IV collagen from the pericellular basement membrane. Interestingly, although tumors overexpressing a GAP activity-deficient mutant of ADAP1 resulted in morphologically complex tumors, those tumor cells failed to breach the basement membrane. Moreover, Adap1 deletion in tumor cells ameliorated the basement membrane breakdown and had less invading cells in the stroma. Our study demonstrates that ADAP1 is a critical mediator of TGF-β-induced cancer invasion and might be exploited for the treatment of high-risk SCC.

Clinical Response of Live-Attenuated, Listeria monocytogenes Expressing Mesothelin (CRS-207) with Chemotherapy in Patients with Malignant Pleural Mesothelioma

PURPOSE

Malignant pleural mesothelioma (MPM) is an aggressive cancer associated with poor prognosis. CRS-207 is a live-attenuated Listeria monocytogenes engineered to express mesothelin, a tumor-associated antigen highly expressed in MPM. CRS-207 induces antitumor immune responses and increases susceptibility of neoplastic cells to immune-mediated killing.

PATIENTS AND METHODS

Patients with unresectable MPM, ECOG 0 or 1, and adequate organ and pulmonary function were enrolled in this multicenter, open-label phase Ib study. They received two priming infusions of 1 × 109 CFU CRS-207, followed by pemetrexed/cisplatin chemotherapy, and CRS-207 booster infusions. Primary objectives were safety and induction of immune response. Secondary/exploratory objectives included tumor response, progression-free survival (PFS), overall survival (OS), immune subset analysis, and gene-expression profiling of tumor.

RESULTS

Of 35 evaluable patients, 89% (31/35) had disease control with one complete response (3%), 19 partial responses (54%), and 10 stable disease (29%). The estimated median duration of response was 5.0 months (95% CI, 3.9-11.5). The median PFS and OS were 7.5 (95% CI, 7.0-9.9) and 14.7 (95% CI, 11.2-21.9) months, respectively. Tumor size reduction was observed post-CRS-207 infusion prior to chemotherapy in 11 of 35 (31%) patients. No unexpected treatment-related serious adverse events or deaths were observed. IHC analysis of pre- and post-CRS-207 treatment tumor biopsies revealed possible reinvigoration and proliferation of T cells, increased infiltration of dendritic and natural killer cells, increased CD8:Treg ratio, and a shift from immunosuppressive M2-like to proinflammatory M1-like macrophages following CRS-207 administration.

CONCLUSIONS

Combination of CRS-207 and chemotherapy induced significant changes in the local tumor microenvironment and objective tumor responses in a majority of treated patients.

Abstract 4491: Association of intratumoral immunologic profile with overall survival in metastatic pancreatic cancer patients treated with combination immunotherapy with or without PD-1 blockade

Background: Metastatic pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis with a 5-year survival rate of 8%. Single-agent immunotherapies fail to show clinical activity due to a complex tumor microenvironment (TME) and lack of effector T cells. We previously showed in a neoadjuvant clinical trial that an irradiated, granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting, allogeneic PDAC vaccine (GVAX) recruited T cells into tumor and upregulated the PD-1/PD-L1 pathway1. Here we describe the first clinical testing of GVAX prime given with attenuated listeria monocytogenes expressing mesothelin (CRS-207) boost alone or in combination with nivolumab to block PD-1 signaling in metastatic PDAC patients, and evaluated changes in the TME.

Experimental Design: 22 metastatic PDAC biopsy pairs were obtained at baseline and after 2 GVAX prime and 1 CRS-207 boost from 96 vaccinated patients. Nivolumab was administered with each vaccine in patients randomized to vaccine + nivolumab arm. Biopsies containing &gt;30% tumor cellularity were chosen for multiplex immunohistochemistry (IHC) to examine changes in immune cell subtypes and their signaling pathways in tumors. We did a comparative analysis looking at lymphoid and myeloid complexity, immune function, and PD-L1 status of patients with overall survival (OS) &lt;150 days [short OS, n=6], 150-300 days [middle OS, n=11], and &gt;300 days [long OS, n=5] or by treatment arm.

Results: Favorable OS correlated with low CD68+ myeloid cell and high lymphoid cell numbers, which was detected after prime-boost. Evaluation of the functional status of CD8+ T cells after prime-boost of patients with long OS revealed a 10.2% increase in EOMES+PD1- effector memory and 1.4% decrease in EOMES+PD1+ exhausted T cells. At baseline, fewer CSF1R+ tumor associated macrophages (TAMs), CD68+CD163+ and CD163- myeloid cells in tumors was associated with long OS. We analyzed nivolumab’s effect on the TME and found that tumors from nivolumab-treated patients displayed a decrease in CD68+ myeloid cells after prime-boost compared to baseline. Interestingly, CD163+ TAMs in tumors of nivolumab-treated patients expressed higher PD-L1 levels.

Conclusion: This study suggests that induction of lymphoid-inflamed expression profiles with less exhausted and more effector memory CD8+ T cells during treatment is associated with long OS independent of nivolumab treatment. Fewer TAMs in pre-treatment biopsies and a low myeloid: lymphoid cell ratio in post-immunotherapy tumor samples may be predictive of improved survival. Our findings also suggest that nivolumab induces PD-L1 expression on myeloid cells. Continual identification of key tissue-based biomarkers that correlate with OS may be useful for predicting therapeutic response.

1) Lutz E. (2014) Cancer Immunol Res. Jul;2(7):616-31.

Citation Format: Annie A. Wu, Takahiro Tsujikawa, Gina Choe, Teresa Beechwood, Lisa M. Coussens, Jennifer N. Durham, Elizabeth M. Jaffee, Dung T. Le. Association of intratumoral immunologic profile with overall survival in metastatic pancreatic cancer patients treated with combination immunotherapy with or without PD-1 blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4491.

Abstract 4038: In-depth PD-L1 scoring reveals potential correlations between tumor-intrinsic PD-L1 and myeloid-inflamed profiles in head and neck cancer

Programmed cell death protein-1 (PD-1) inhibition has been showing encouraging results for recurrent/metastatic head and neck squamous cell carcinoma (HNSCC), which simultaneously requires the development of predictive biomarkers to guide selection of conventional and immune checkpoint therapies. Most recently, PD-L1 IHC scoring of tumor and inflammatory cells, but not of tumor cells alone, has been reported as effective metrics for selection between PD-1 inhibition and standard combination therapy of platinum/5-FU/cetuximab for HNSCC. Toward establishment of PD-L1 score-based biomarkers, the present study is aimed to evaluate in-depth PD-L1 profiles of tumor and immune cells in association with immune complexity profiles of HPV-positive and negative HNSCC via 12-marker multiplex immunohistochemistry (IHC) and image cytometry. As previously reported (Tsujikawa et al. Cell Reports. 2017), oropharyngeal HNSCC cases were divided into three clusters of lymphoid-, hypo-, and myeloid-inflamed profiles based on cell densities of immune cell lineages. Averages of PD-L1+ percentages in immune cells were 5.3, 7.1, and 12.8 in lymphoid-, hypo-, myeloid-inflamed groups, respectively. High PD-L1 expression on immune cells was observed in CD163+CSF1R+ tumor-associated macrophages and mature dendritic cell populations particularly in intra-tumor regions. Interestingly, averages of PD-L1+ percentages in tumor cells were 0.17, 0.64, and 5.3 in lymphoid-, hypo-, myeloid-inflamed groups, respectively, suggesting that tumor-intrinsic PD-L1 expression without lymphoid-inflamed profiles was potentially associated with myeloid-inflamed profiles. To further evaluate the prognostic significance of PD-L1 expression with low lymphoid-inflamed profiles, we evaluated the the Cancer Genome Atlas (TCGA) HNSCC cohort (N = 528), and observed that high PD-L1 expression with low CD8+ T cell cytolytic activity was associated with short overall survival. Immune complexity analysis for longitudinal specimens from a nivolumab-resistant case with PD-L1 expression on tumor cells revealed the potential involvement of myeloid-inflamed status, suggesting the presence of differential PD-L1 profiles between tumor and immune cells in the context of lymphoid/myeloid-inflamed status. Those findings together indicate that combination of in-depth PD-L1 scoring and immune complexity profiling may contribute to biomarker development toward optimized management for HNSCC.Acknowledgement: This project was supported by the Japan Society for the Promotion of Science Grant-in-Aid (17H07016).

Citation Format: Takahiro Tsujikawa, Tsutomu Kawaguchi, Kanako Yoshimura, Junichi Mitsuda, Akihito Aarai, Shigeru Hirano. In-depth PD-L1 scoring reveals potential correlations between tumor-intrinsic PD-L1 and myeloid-inflamed profiles in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4038.

Dissecting the Stromal Signaling and Regulation of Myeloid Cells and Memory Effector T Cells in Pancreatic Cancer

PURPOSE

Myeloid cells are a prominent immunosuppressive component within the stroma of pancreatic ductal adenocarcinoma (PDAC). Previously, targeting myeloid cells has had limited success. Here, we sought to target the myeloid cells through modifying a specific stromal component.

EXPERIMENTAL DESIGN

A murine model of metastatic PDAC treated with an irradiated whole-cell PDAC vaccine and PDAC specimens from patients treated with the same type of vaccine were used to assess the immune-modulating effect of stromal hyaluronan (HA) degradation by PEGPH20.

RESULTS

Targeting stroma by degrading HA with PEGPH20 in combination with vaccine decreases CXCL12/CXCR4/CCR7 immunosuppressive signaling axis expression in cancer-associated fibroblasts, myeloid, and CD8⁺ T cells, respectively. This corresponds with increased CCR7^- effector memory T-cell infiltration, an increase in tumor-specific IFNγ, and improved survival. In the stroma of human PDACs treated with the same vaccine, decreased stromal CXCR4 expression significantly correlated with decreased HA and increased cytotoxic activities, suggesting CXCR4 is an important therapeutic target.

CONCLUSIONS

This study represents the first to dissect signaling cascades following PDAC stroma remodeling via HA depletion, suggesting this not only overcomes a physical barrier for immune cell trafficking, but alters myeloid function leading to downstream selective increases in effector memory T-cell infiltration and antitumor activity.

Poor Response to Neoadjuvant Chemotherapy Correlates with Mast Cell Infiltration in Inflammatory Breast Cancer

Our understanding is limited concerning the tumor immune microenvironment of inflammatory breast cancer (IBC), an aggressive form of primary cancer with low rates of pathologic complete response to current neoadjuvant chemotherapy (NAC) regimens. We retrospectively identified pretreatment (N = 86) and matched posttreatment tissue (N = 27) from patients with stage III or de novo stage IV IBC who received NAC followed by a mastectomy. Immune profiling was performed including quantification of lymphoid and myeloid infiltrates by IHC and T-cell repertoire analysis. Thirty-four of 86 cases in this cohort (39.5%) achieved a pathologic complete response. Characterization of the tumor microenvironment revealed that having a lower pretreatment mast cell density was significantly associated with achieving a pathologic complete response to NAC (P = 0.004), with responders also having more stromal tumor-infiltrating lymphocytes (P = 0.035), CD8⁺ T cells (P = 0.047), and CD20⁺ B cells (P = 0.054). Spatial analysis showed close proximity of mast cells to CD8⁺ T cells, CD163⁺ monocytes/macrophages, and tumor cells when pathologic complete response was not achieved. PD-L1 positivity on tumor cells was found in fewer than 2% of cases and on immune cells in 27% of cases, but with no correlation to response. Our results highlight the strong association of mast cell infiltration with poor response to NAC, suggesting a mechanism of treatment resistance and a potential therapeutic target in IBC. Proximity of mast cells to immune and tumor cells may suggest immunosuppressive or tumor-promoting interactions of these mast cells.

Differential isoform expression of SERCA and myosin heavy chain in hypopharyngeal muscles

Composition of slow, fast and hybrid fibres of pharyngeal muscles, associated with pharyngeal movements and regulation, has been rarely studied. The present study aimed to identify expression of sarcoplasmic reticulum Ca2⁺ ATPase (SERCA) and myosin heavy chain (MHC) and hybrid isoforms in different pharyngeal muscles of young and aged rats as well as humans. Isoform expression profiles of SERCA, MHC and hybrid isoforms among six components of pharyngeal muscle were immunohistochemically evaluated in rat and human. The result showed that pharyngeal muscles predominantly expressed fast fibres (SERCA1 and MHCII), whereas expression of slow fibres (SERCA2 and MHCI) was low, but different depending on muscle components. Inner layer of pharyngeal muscles expressed more SERCA2 and hybrid fibres than the outer layer. Pharyngeal muscles in aged rats showed increased hybrid fibers and SERCA2. Human thyropharyngeus also showed a higher portion of fast fibres compared to cricopharyngeus. Thus, in contrast to abundance of fast fibres, slow and hybrid fibres are differentially expressed depending on muscle components and layers as well as aging. These results lead to further understanding of coordinated regulation for speech and swallowing. The unique data presented in this study on SERCA isoform expressions in both rats and human suggest an ability to handle calcium changes according functional demands.

Tumor immune microenvironment characteristics of papillary thyroid carcinoma are associated with histopathological aggressiveness and BRAF mutation status

BACKGROUND

Papillary thyroid carcinoma (PTC) follows an indolent course; however, up to 30% of patients develop recurrent disease requiring further treatment. Profiling PTC immune complexity may provide new biomarkers for improved risk prediction.

METHODS

Immune complexity profiles were quantitatively evaluated by multiplex immunohistochemistry (mIHC) in archived tissue sections from 39 patients with PTC, and were assessed for correlations with aggressive histopathological features based on the presence of lymphovascular invasion and/or extrathyroidal extension, and BRAF V600E mutational status.

RESULTS

mIHC revealed two distinct immune clusters stratifying patients: a lymphoid-inflamed group (higher CD8⁺ T cells, reduced dendritic and mast cells) and a myeloid/hypo-inflamed group that correlated with aggressive pathological features. BRAF mutation was not associated with aggressive pathological features but did correlate with increased mast cell density.

CONCLUSIONS

Distinct immune microenvironments exist in PTC correlating with pathological aggressiveness. Immune-based biomarkers associated with possible tumor-immune interactions may be used for risk stratification.

Radiation-induced angiosarcoma of the parotid gland after postoperative radiotherapy for hypopharyngeal carcinoma

Secondary carcinogenesis within the irradiation range is one of the most severe problems in cancer survivors. A 60-year-old woman developed hypopharyngeal carcinoma, and she received radical surgery and postoperative radiotherapy. Eight years later, brown pigmentation and induration were observed in the left subaural region. Fine-needle aspiration biopsy revealed malignancy and the parotid tumor was diagnosed as recurrence of hypopharyngeal carcinoma. Neoadjuvant chemotherapy followed by radical parotidectomy was performed. The pathological diagnosis was angiosarcoma, which was most likely induced by past irradiation. About two months after surgery, lung metastases were detected. Docetaxel did not affect to lung metastases, but paclitaxel therapy was partially effective. The lung tumors increased in size, and brain metastases developed, resulting in death. Both neoadjuvant chemotherapy and radical surgery played important roles in the local disease control. Administration of newer agents as adjuvant chemotherapeutic agent should also be considered for improving the prognosis.

Robust Cell Detection and Segmentation for Image Cytometry Reveal Th17 Cell Heterogeneity

Image cytometry enables quantitative cell characterization with preserved tissue architecture; thus, it has been highlighted in the advancement of multiplex immunohistochemistry (IHC) and digital image analysis in the context of immune-based biomarker monitoring associated with cancer immunotherapy. However, one of the challenges in the current image cytometry methodology is a technical limitation in the segmentation of nuclei and cellular components particularly in heterogeneously stained cancer tissue images. To improve the detection and specificity of single-cell segmentation in hematoxylin-stained images (which can be utilized for recently reported 12-biomarker chromogenic sequential multiplex IHC), we adapted a segmentation algorithm previously developed for hematoxlin and eosin-stained images, where morphological features are extracted based on Gabor-filtering, followed by stacking of image pixels into n-dimensional feature space and unsupervised clustering of individual pixels. Our proposed method showed improved sensitivity and specificity in comparison with standard segmentation methods. Replacing previously proposed methods with our method in multiplex IHC/image cytometry analysis, we observed higher detection of cell lineages including relatively rare T_H 17 cells, further enabling sub-population analysis into T_H 1-like and T_H 2-like phenotypes based on T-bet and GATA3 expression. Interestingly, predominance of T_H 2-like T_H 17 cells was associated with human papilloma virus (HPV)-negative status of oropharyngeal squamous cell carcinoma of head and neck, known as a poor-prognostic subtype in comparison with HPV-positive status. Furthermore, T_H 2-like T_H 17 cells in HPV-negative head and neck cancer tissues were spatiotemporally correlated with CD66b⁺ granulocytes, presumably associated with an immunosuppressive microenvironment. Our cell segmentation method for multiplex IHC/image cytometry potentially contributes to in-depth immune profiling and spatial association, leading to further tissue-based biomarker exploration. © 2019 International Society for Advancement of Cytometry.

IFNγ-activated dermal lymphatic vessels inhibit cytotoxic T cells in melanoma and inflamed skin

Mechanisms of immune suppression in peripheral tissues counteract protective immunity to prevent immunopathology and are coopted by tumors for immune evasion. While lymphatic vessels facilitate T cell priming, they also exert immune suppressive effects in lymph nodes at steady-state. Therefore, we hypothesized that peripheral lymphatic vessels acquire suppressive mechanisms to limit local effector CD8+ T cell accumulation in murine skin. We demonstrate that nonhematopoietic PD-L1 is largely expressed by lymphatic and blood endothelial cells and limits CD8+ T cell accumulation in tumor microenvironments. IFNγ produced by tissue-infiltrating, antigen-specific CD8+ T cells, which are in close proximity to tumor-associated lymphatic vessels, is sufficient to induce lymphatic vessel PD-L1 expression. Disruption of IFNγ-dependent crosstalk through lymphatic-specific loss of IFNγR boosts T cell accumulation in infected and malignant skin leading to increased viral pathology and tumor control, respectively. Consequently, we identify IFNγR as an immunological switch in lymphatic vessels that balances protective immunity and immunopathology leading to adaptive immune resistance in melanoma.

Targeting myeloid-inflamed tumor with anti-CSF-1R antibody expands CD137+ effector T-cells in the murine model of pancreatic cancer

BACKGROUND

The pancreatic cancer vaccine, GVAX, induces novel lymphoid aggregates in the otherwise immune quiescent pancreatic ductal adenocarcinoma (PDAC). GVAX also upregulates the PD-1/PD-L1 pathway, and a pre-clinical model demonstrated the anti-tumor effects of combination GVAX and anti-PD-1 antibody therapy (GVAX/αPD-1). Resistance to GVAX was associated with an immune-suppressive myeloid cell infiltration, which may limit further therapeutic gains of GVAX/αPD-1 therapy. The expression of CSF-1R, a receptor important for myeloid cell migration, differentiation and survival, and the effect of its therapeutic blockade in the context of GVAX in PDAC has not been investigated.

METHODS

Lymphoid aggregates appreciated in 24 surgically resected PDAC from patients who received one dose of neoadjuvant GVAX were analyzed with multiplex immunohistochemistry. Flow cytometry analysis of tumor infiltrating T-cells in a murine model of PDAC was performed to investigate the therapeutic effects and mechanism of anti-CSF-1R/anti-PD-1/GVAX combination immunotherapy.

RESULTS

High CSF-1R expression in resected PDAC from patients who received neoadjuvant GVAX was associated with a higher myeloid to lymphoid cell ratio (p < 0.05), which has been associated with poorer survival. This higher CSF-1R expression was associated with a higher intra-tumoral infiltration of immature dendritic cells (p < 0.05), but not mature dendritic cells (p = 0.132). In the pre-clinical murine model, administering anti-CSF-1R antibody prior to and after GVAX/αPD-1 ("pre/post-αCSF-1R + αPD-1 + GVAX") enhanced the survival rate compared to GVAX/αPD-1 dual therapy (p = 0.005), but administering anti-CSF-1R only before GVAX/αPD-1 did not (p = 0.41). The "pre/post-αCSF-1R + αPD-1 + GVAX" group also had higher intra-tumoral infiltration of PD-1 + CD8+ and PD-1 + CD4+ T-cells compared to αPD-1/GVAX (p < 0.001). Furthermore, this regimen increased the intra-tumoral infiltration of PD-1 + CD137 + CD8+, PD-1 + CD137 + CD4+ and PD-1 + OX40 + CD4+ T-cells (p < 0.001). These PD-1 + CD137 + CD8+ T-cells expressed high levels of interferon-γ (median 80-90%) in response to stimulation with CD3/CD28 activation beads, and this expression was higher than that of PD-1 + CD137-CD8+ T-cells (p < 0.001).

CONCLUSIONS

The conversion of exhausted PD-1+ T-cells to CD137+ activated effector T-cells may contribute to the anti-tumor effects of the anti-CSF-1R/anti-PD-1/GVAX combination therapy. Anti-CSF-1R antibody with anti-PD-1 antibody and GVAX have the potential be an effective therapeutic strategy for treatment of PDAC.

Ibuprofen supports macrophage differentiation, T cell recruitment, and tumor suppression in a model of postpartum breast cancer

BACKGROUND

Women diagnosed with breast cancer within 5 years postpartum (PPBC) have poorer prognosis than age matched nulliparous women, even after controlling for clinical variables known to impact disease outcomes. Through rodent modeling, the poor prognosis of PPBC has been attributed to physiologic mammary gland involution, which shapes a tumor promotional microenvironment through induction of wound-healing-like programs including myeloid cell recruitment. Previous studies utilizing immune compromised mice have shown that blocking prostaglandin synthesis reduces PPBC tumor progression in a tumor cell extrinsic manner. Given the reported roles of prostaglandins in myeloid and T cell biology, and the established importance of these immune cell populations in dictating tumor growth, we investigate the impact of involution on shaping the tumor immune milieu and its mitigation by ibuprofen in immune competent hosts.

METHODS

In a syngeneic (D2A1) orthotopic Balb/c mouse model of PPBC, we characterized the impact of mammary gland involution and ibuprofen treatment on the immune milieu in tumors and draining lymph nodes utilizing flow cytometry, multiplex IHC, lipid mass spectroscopy and cytokine arrays. To further investigate the impact of ibuprofen on programming myeloid cell populations, we performed RNA-Seq on in vivo derived mammary myeloid cells from ibuprofen treated and untreated involution group mice. Further, we examined direct effects of ibuprofen through in vitro bone marrow derived myeloid cell cultures.

RESULTS

Tumors implanted into the mammary involution microenvironment grow more rapidly and display a distinct immune milieu compared to tumors implanted into glands of nulliparous mice. This milieu is characterized by increased presence of immature monocytes and reduced numbers of T cells and is reversed upon ibuprofen treatment. Further, ibuprofen treatment enhances Th1 associated cytokines as well as promotes tumor border accumulation of T cells. Safety studies demonstrate ibuprofen does not impede gland involution, impact subsequent reproductive success, nor promote auto-reactivity as detected through auto-antibody and naïve T cell priming assays.

CONCLUSIONS

Ibuprofen administration during the tumor promotional microenvironment of the involuting mammary gland reduces overall tumor growth and enhances anti-tumor immune characteristics while avoiding adverse autoimmune reactions. In sum, these studies implicate beneficial prophylactic use of ibuprofen during the pro-tumorigenic window of mammary gland involution.

Abstract 220: Intra-tumor immune heterogeneity is associated with prognosis of oropharyngeal head and neck squamous cell carcinoma

As cell-cell interactions among tumor and immune cells are known to contribute to tumor progression, in depth evaluation of tumor-immune heterogeneity will enable biomarker-guided patient stratification and improvement of treatment response. Here we examined head and neck squamous cell carcinomas (HNSCC) to reveal the prognostic significance of leukocytes in tumors with regards to their complexity, effector status and spatial characteristics via multiplex immunohistochemistry and image cytometry. To accomplish this, we examined oropharyngeal HNSCC (N = 38), where lymphoid, myeloid, and hypo-inflamed leukocyte complexity correlated with HPV-status (Tsujikawa et al. Cell Reports, 2017). In the present study, quantitative analysis of cell density and distribution of 14-distinct immune cell lineages (e.g., CD8+ T cells, regulatory T cells, Th1, Th2, Th17, Th0 lymphocytes, B cells, NK cells, CD163+ and CD163- macrophages, mature and immature dendritic cells, mast cells, granulocytes) was analyzed via immune cell density mapping and tissue segmentation algorithms. We revealed tropism of polarized Th1-type cells within tumor nests versus stroma in HPV-associated HNSCC. In addition, Cox regression analysis of cell density and distribution of the 14 immune populations revealed that CD66b+ granulocyte infiltration within tumor nests reflected a negative prognostic indicator for HNSCC outcome. Furthermore, cell-cell proximity analysis in HPV-associated HNSCC further revealed a correlation between PD-L1 positive immune cells, and micro-regionally polarized immune characteristics biased towards Th1, coincident with high density of CD8+ T cells. These results reveal intra-tumor immune heterogeneity is associated with micro-regional immune complexity profiles, and provide insight into in situ immune characteristics that may aid patient stratification for immune therapy going forward. Acknowledgement: This project was supported by the Japan Society for the Promotion of Science Grant-in-Aid for Young Scientists (Start-up, 17H07016), Oregon Clinical and Translational Research Institute (OCTRI), grant number (UL1TR000128) from the National Center for Advancing Translational Sciences (NCATS) at the National Institutes of Health (NIH), and P30 CA069533-17 OHSU Knight Cancer Institute. LMC acknowledges support from the NIH/NCI, DOD BCRP Era of Hope Scholar Expansion Award, Susan G. Komen Foundation, Stand Up To Cancer - Lustgarten Foundation Pancreatic Cancer Convergence Dream Team Translational Research Grant, Breast Cancer Research Foundation, and the Brenden-Colson Center for Pancreatic Health.

Citation Format: Takahiro Tsujikawa, Guillaume Thibault, Young Hwan Chang, Edward El Rassi, Daniel R. Clayburgh, David Sauer, Akihito Arai, Molly F. Kulesz-Martin, Motomi Mori, Shigeru Hirano, Paul W. Flint, Lisa M. Coussens. Intra-tumor immune heterogeneity is associated with prognosis of oropharyngeal head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 220.

Abstract 611: PD-1-based combination immunotherapy reinvigorates CD8+ T cells in metastatic pancreatic cancer patients with improved survival

Background: Metastatic pancreatic ductal adenocarcinoma (PDAC) is lethal with a 5-year survival rate of 2%. Single-agent immunotherapies fail to show clinical activity due to a complex tumor microenvironment (TME) and lack of effector T cells. We previously showed that an irradiated, granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting, allogeneic PDAC vaccine (GVAX) given as neoadjuvant recruited T cells into the tumor and upregulated the PD-1/PD-L1 pathway. Here we described the first testing of GVAX prime given with attenuated listeria monocytogenes expressing mesothelin (CRS-207) boost given with or without nivolumab to block PD-1 signaling and evaluated changes in the TME.

Experimental Design: Metastatic pancreatic tumor biopsies were obtained at baseline and after 2 GVAX prime and 1 CRS-207 boost from vaccinated patients. Nivolumab was administered with each vaccine in patients randomized to the nivolumab arm. Biopsies containing high density of tumor cells (&gt;30%) were chosen for multiplex immunohistochemistry (IHC) to examine changes in the immune cell subtypes and their signals in tumors. We did a comparative analysis looking at lymphoid, myeloid complexity, and immune functional status in the tumor microenvironment of patients who have overall survival &lt;6 months [short OS] and &gt;6 months [long OS].

Results: Post-immunotherapy changes in immune cell profiles correlated with overall survival. After prime-boost, expansion of CD8+ T cells was observed in the long OS group. Evaluation of the functional status of CD8+ T cells after prime-boost of short OS group showed an EOMES+PD1+ exhausted phenotype. In the myeloid compartment, low CSF1R+ tumor associated macrophages and CD68+ CD163+ and CD163- myeloid frequency in post-immunotherapy tumors were associated with less exhaustion of CD8+ T cells and long OS. The clinical trial is ongoing and blinded to study arm; thus, we have not yet analyzed whether nivolumab influences results. These data will be available at the time of abstract presentation.

Conclusion: This study provides evidence that longitudinal changes in immune cell complexity profiles can be correlated with overall survival. Increases in CD8+ early effectors and decreases in monocytes in baseline versus post-immunotherapy tumors are associated with improved survival. The exhausted CD8+ T cell profile in short OS patients may predict early responders versus nonresponders to vaccine containing immunotherapy.

Citation Format: Annie A. Wu, Takahiro Tsujikawa, Gina Choe, Teresa Beechwood, Lisa M. Coussens, Jennifer N. Durham, Elizabeth M. Jaffee, Dung T. Le. PD-1-based combination immunotherapy reinvigorates CD8+ T cells in metastatic pancreatic cancer patients with improved survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 611.

Abstract P3-05-08: Lymphoid and myeloid cell characterization of inflammatory breast cancer tumor microenvironment and correlation to pathological complete response

Background: Inflammatory breast cancer (IBC) is an aggressive form of breast cancer with poor response rates to current chemotherapy regimens. With recent successes of immune targeted therapies in other solid tumors and a growing understanding of how the immune tumor microenvironment (TME) affects non-IBC outcomes, we sought to characterize the immune TME in IBC to identify biomarkers of treatment response and potential targets for drug development.

Methods: Pre-treatment core biopsy samples were identified from the MD Anderson Cancer Center IBC tissue bank from patients with stage III and de novo stage IV (with T4d) disease who received neoadjuvant chemotherapy (NAC) with intent to take to mastectomy. Lymphocytes were characterized by stromal tumor infiltrating lymphocyte (sTIL) quantification, CD8 T cell quantification, and T cell receptor sequencing. PD-L1 expression was assessed using DAKO 22C3 clone on tumor and immune cells. Myeloid cells were characterized using a multiplex immunohistochemistry approach, using CD68 and CD163 for macrophage markers, tryptase for mast cell marker, HLA-DR for class II antigen presentation marker, and cytokeratin as tumor marker. Spatial analyses were performed by determining probabilities of finding cell 1 of interest within 20 uM of cell 2 of interest and computing area under the curve for statistical comparison.

Results: 91 patients with stage III (N=62) or de novo stage IV (n=29) disease were identified. Breast cancer subtype included 25 triple negative, 34 HER2+ and 32 HER2-HR+. 86 patients received a mastectomy, of whom 33 (38.4%) patients experienced a pathologic complete response (pCR). sTIL was higher in stage III tumors (11.9 vs 4.8%, p&lt;0.001) and in those having a pCR (13.8 vs 7.3%, p=0.019). CD8 T cell density (available in 48 cases) similarly was higher in stage III patients (360.3 vs 178.8 counts/mm2, p=0.040) and pCR cases (452.3 vs 219.2 counts/mm2, p=0.080) but also higher in HER2+ disease (560.9 for HER2+ vs 239.9 counts/mm2, p=0.087 for TNBC and 153.6 counts/mm2, p=0.005 for HER2-HR+). T cell clonality (available in 32 cases) ranged from 0.004 to 0.242 but showed no correlation to tumor characteristics or response. PD-L1 complete tumor membranous expression was seen in only 1 of 47 cases, whereas PD-L1 positivity on immune cells was seen on 36.2% of cases; neither correlated to response. Myeloid cell assessment (available in 25 cases) showed higher mast cell infiltration in non-pCR cases (63.8 vs 26.8 counts/mm2, p=0.008) and spatial analysis (performed on 10 cases) identified that closer proximity of mast cells to CD8 T cells correlates with response (AUC 6.0 vs 2.2, p=0.017), suggesting a possible immunosuppressive mechanism. HLA-DR analysis demonstrated no difference by response as a single stain marker, but co-localization of HLA-DR with cell type shows higher HLA-DR expression on tumor cells in non-responders (14.6 vs 1.6%, p=0.031).

Conclusions: Higher TIL and CD8 T cell density are correlated with improved responses to NAC in IBC. Mast cell infiltration and HLA-DR expression on tumor cells are inversely correlated to response and suggest possible mechanisms of resistance. Mast cells could present potential therapeutic target in IBC.

Citation Format: Reddy SM, Reuben A, Jiang H, Roszik J, Tetzlaff MT, Reuben J, Wang L, Tsujikawa T, Barua S, Rao A, Villareal L, Wood A, Woodward W, Ueno NT, Krishnamurthy S, Wargo JA, Mittendorf EA. Lymphoid and myeloid cell characterization of inflammatory breast cancer tumor microenvironment and correlation to pathological complete response [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-05-08.

Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients

Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral and gut microbiome of melanoma patients undergoing anti-programmed cell death 1 protein (PD-1) immunotherapy (n = 112). Significant differences were observed in the diversity and composition of the patient gut microbiome of responders versus nonresponders. Analysis of patient fecal microbiome samples (n = 43, 30 responders, 13 nonresponders) showed significantly higher alpha diversity (P < 0.01) and relative abundance of bacteria of the Ruminococcaceae family (P < 0.01) in responding patients. Metagenomic studies revealed functional differences in gut bacteria in responders, including enrichment of anabolic pathways. Immune profiling suggested enhanced systemic and antitumor immunity in responding patients with a favorable gut microbiome as well as in germ-free mice receiving fecal transplants from responding patients. Together, these data have important implications for the treatment of melanoma patients with immune checkpoint inhibitors.

Quantitative Multiplex Immunohistochemistry Reveals Myeloid-Inflamed Tumor-Immune Complexity Associated with Poor Prognosis

Here, we describe a multiplexed immunohistochemical platform with computational image processing workflows, including image cytometry, enabling simultaneous evaluation of 12 biomarkers in one formalin-fixed paraffin-embedded tissue section. To validate this platform, we used tissue microarrays containing 38 archival head and neck squamous cell carcinomas and revealed differential immune profiles based on lymphoid and myeloid cell densities, correlating with human papilloma virus status and prognosis. Based on these results, we investigated 24 pancreatic ductal adenocarcinomas from patients who received neoadjuvant GVAX vaccination and revealed that response to therapy correlated with degree of mono-myelocytic cell density and percentages of CD8⁺ T cells expressing T cell exhaustion markers. These data highlight the utility of in situ immune monitoring for patient stratification and provide digital image processing pipelines to the community for examining immune complexity in precious tissue sections, where phenotype and tissue architecture are preserved to improve biomarker discovery and assessment.

Using an In-House Approach to Computer-Assisted Design and Computer-Aided Manufacturing Reconstruction of the Maxilla

PURPOSE

Computer-assisted design (CAD) and computer-aided manufacturing (CAM) techniques are in widespread use for maxillofacial reconstruction. However, CAD/CAM surgical guides are commercially available only in limited areas. To use this technology in areas where these commercial guides are not available, the authors developed a CAD/CAM technique in which all processes are performed by the surgeon (in-house approach). The authors describe their experience and the characteristics of their in-house CAD/CAM reconstruction of the maxilla.

PATIENTS AND METHODS

This was a retrospective study of maxillary reconstruction with a free osteocutaneous flap. Free CAD software was used for virtual surgery and to design the cutting guides (maxilla and fibula), which were printed by a 3-dimensional printer. After the model surgery and pre-bending of the titanium plates, the actual reconstructions were performed. The authors compared the clinical information, preoperative plan, and postoperative reconstruction data. The reconstruction was judged as accurate if more than 80% of the reconstructed points were within a deviation of 2 mm.

RESULTS

Although on-site adjustment was necessary in particular cases, all 4 reconstructions were judged as accurate. In total, 3 days were needed before the surgery for planning, printing, and pre-bending of plates. The average ischemic time was 134 minutes (flap suturing and bone fixation, 70 minutes; vascular anastomoses, 64 minutes). The mean deviation after reconstruction was 0.44 mm (standard deviation, 0.97). The deviations were 67.8% for 1 mm, 93.8% for 2 mm, and 98.6% for 3 mm. The disadvantages of the regular use of CAD/CAM reconstruction are the intraoperative changes in defect size and local tissue scarring.

CONCLUSION

Good accuracy was obtained for CAD/CAM-guided reconstructions based on an in-house approach. The theoretical advantage of computer simulation contributes to the accuracy. An in-house approach could be an option for maxillary reconstruction.

Multiplexed immunohistochemistry image analysis using sparse coding

Multiplexed immunohistochemical (IHC) methods have been developed to evaluate multiple protein biomarkers in a single formalin-fixed paraffin-embedded (FFPE) tissue section. Since distinct populations of resident and recruited immune cells in tissues (and tumors) not only regulate progression of malignant disease, these also represent targets for novel immune-based therapies; thus, improved tissue biomarker assessment evaluating immune responses in situ are needed. To objectively identify distinct cell subsets in tissues and tumors, we adopted sparse coding approaches enabling modeling of data vectors as sparse linear combinations of basis elements, to audit cellular presence and phenotypes using image cytometry datasets with unbiased assessments. By doing comparative analyses between manual gating (ground truth) and sparse coding, we report that results are comparable as obtained by manual gating strategies, and demonstrate robustness and objectivity of this novel bioinformatics approach.

Abstract NG02: Lymphatic vessels: Balancing immune priming and immune evasion in melanoma

Lymphatic vessel remodeling and lymphangiogenesis is correlated with melanoma progression and lymph node metastasis. While lymphatic vessels provide an important route for disseminating tumor cells, they are also a crucial interface between a developing malignancy and the host immune response. Rather than acting as passive conduits, lymphatic vessels directly regulate their transport function and facilitate leukocyte trafficking for efficient induction of adaptive immunity in downstream draining lymph nodes. We recently published that in the absence of dermal lymphatic vessels, the tumor microenvironment of murine melanoma remains completely uninflamed and fails to induce a robust T-cell response (1). Consistently, TCGA analysis of human cutaneous metastatic melanoma identified positive correlations between LEC gene expression and immune genes, including a T cell-inflamed signature, indicating a relationship between lymphatic vessel remodeling and local immunity. Furthermore, others have recently demonstrated that lymphatic vessel density (LVD) in combination with intratumoral T cell function stratified best overall survival in nonmetastatic and metastatic colorectal cancer (2). In contrast to this, however, many reports independently correlate peritumoral LVD with lymph node metastasis and some poor prognosis (3). Furthermore, our previous work demonstrated that vascular endothelial growth factor C (VEGFC)-driven lymphangiogenesis in the context of murine melanoma drove increased leukocyte infiltration but associated with poor CD8+ T cell priming in draining lymph nodes (4). We therefore hypothesize that lymphatic vessels are (A) required for induction of adaptive immunity but (B) acquire immunosuppressive activity as a function of the accumulation of local cytotoxic immunity. Furthermore, we predict that LVD may be a relevant biomarker of in situ immune responsiveness and response to therapy (5).

To test the first part of this hypothesis (A), we have continued our published work and used a cutaneous model of viral infection to demonstrate the requirement for lymphatic vessel drainage in cutaneous immunity. Following cutaneous vaccinia infection we demonstrate that in the absence of lymphatic vessel transport, both cellular and humoral adaptive immune responses fail to initiate, leading to enhanced cutaneous immunopathology and persistent viral load. The complete absence of primed CD8+ and CD4+ T cells in cutaneous tissue following challenge mirrors our observations in melanoma and is consistent with correlations of intratumoral lymphocytes and LVD both by our group in cutaneous metastatic melanoma as well as by others. This unequivocal requirement for a functional lymphatic vasculature in the priming of cutaneous immunity further supports the prediction that LVD may be a novel biomarker of immune reactivity within tumor parenchyma. To test this, we simultaneously evaluated immune and vascular components in human primary melanoma samples using a multiplex-immunohistochemistry-based approach. Tissue regions that include tumor/stroma borders and show high CD8+ T-cell infiltrates are selected for analysis, followed by tissue segmentation, and automated detection of cell populations within intratumoral regions and bordering stroma. Interestingly, those tumors with enhanced hematopoietic infiltrate (CD68 and CD8) also appear to demonstrate increased vasculature, both blood (CD31 and CD34) and lymphatic (D2-40 and Prox1). Preliminary data demonstrate that lymphatic vessels, blood vessels, and CD8+ T cells are significantly enriched at the tumor-stroma border in primary melanoma and positively correlate with one another, indicating that lymphatic vessels may be a dynamic component of the “T cell-inflamed” microenvironment.

While we demonstrate that lymphatic vessels are necessary for immune induction, we further hypothesized (B) that in the context of an ongoing immune response lymphatic vessels adapt their function to promote immune resolution. The adaptive resistance hypothesis proposes that upon accumulation of local cytotoxic immunity, both tumors as well as stromal components adapt and acquire therapeutically relevant immunosuppressive function. We demonstrate that peripheral, tumor-associated lymphatic endothelial cells (LEC; CD45-CD31+gp38+) acquire expression of immunoregulatory proteins, most notably programmed death receptor ligand-1 (PD-L1) and major histocompatibility complex II (MHCII), coincident with CD8+ T-cell infiltration in an interferon gamma (IFNg)-dependent manner. Adoptive transfer of activated CD8+ T cells induced higher expression of PD-L1 by LECs in B16 F10 tumors, while neutralization of IFNg reduced levels to that of naïve skin. Furthermore, conditional knockout of the IFNgR (Lyve1-Cre) prevented upregulation of PD-L1 on tumor-associated LECs. Notably, lymph node LECs constitutively express PD-L1 and this expression contributes to the attenuation of self-reactive CD8+ T-cell responses (6). Importantly, in the absence of IFNgR on peripheral LECs we observed significantly enhanced accumulation of antigen-specific CD8+ T cells in cutaneous tissue. Thus, cutaneous lymphatic vessels, while necessary for immune induction, acquire immunodulatory properties in a context-dependent manner and may participate in immune evasion within tumor microenvironments.

In conclusion, our work across multiple model systems provides strong experimental evidence to indicate that the lymphatic vasculature is an important, active component of the antitumor immune response and may represent a biomarker to stratify patient response and survival for effective clinical immunotherapy. These data indicate a need to revisit the passive paradigm of lymphatic vessel involvement in tumor progression and metastasis to a more active model whereby lymphatic vessels are both required for antitumor immunity but functionally evolve in response to accumulating cytotoxicity to drive immune evasion.

References:

1. Lund AW et al. Lymphatic vessels regulate immune microenvironments in human and murine melanoma. J Clin Invest 2016;126:3389-402. doi: 10.1172/JCI79434.

2. Mlecnik B et al. The tumor microenvironment and Immunoscore are critical determinants of dissemination to distant metastasis. Sci Transl Med 2016;8:327ra26.

3. Pasquali S et al. Lymphatic biomarkers in primary melanomas as predictors of regional lymph node metastasis and patient outcomes. Pigment Cell Melanoma Res 2013;26:326-37.

4. Lund AW et al. VEGF-C promotes immune tolerance in B16 melanomas and cross-presentation of tumor antigen by lymph node lymphatics. Cell Rep 2012;1:191-9.

5. Lund AW. Rethinking lymphatic vessels and antitumor immunity. Trends Cancer 2016;2:548-51. doi: 10.1016/j.trecan.2016.09.0056. Tewalt EF et al. Lymphatic endothelial cells induce tolerance via PD-L1 and lack of costimulation leading to high-level PD-1 expression on CD8 T cells. Blood 2012;120:4772-82.

Citation Format: Ryan S. Lane, Julia Femel, Jamie Booth, Christopher Loo, Nicholas Nelson, Takahiro Tsujikawa, Guillaume Thibault, Amanda W. Lund. Lymphatic vessels: Balancing immune priming and immune evasion in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr NG02. doi:10.1158/1538-7445.AM2017-NG02

BREAST CANCER HISTOPATHOLOGY IMAGE ANALYSIS PIPELINE FOR TUMOR PURITY ESTIMATION

The translation of genomic sequencing technology to the clinic has greatly advanced personalized medicine. However, the presence of normal cells in tumors is a confounding factor in genome sequence analysis. Tumor purity, or the percentage of cancerous cells in whole tissue section, is a correction factor that can be used to improve the clinical utility of genomic sequencing. Currently, tumor purity is estimated visually by expert pathologists; however, it has been shown that there exist vast inter-observer discrepancies in tumor purity scoring. In this paper, we propose a quantitative image analysis pipeline for tumor purity estimation and provide a systematic comparison between pathologists' scores and our image-based tumor purity estimation.

Abstract A013: Favorable changes in tumor microenvironment following intravenous dosing with live attenuated Listeria monocytogenes-based immunotherapy

Modification of the tumor microenvironment (TME) to promote immune-mediated tumor cell destruction is considered to be an essential step for effective immunotherapy. We are evaluating recombinant live-attenuated, double deleted Listeria monocytogenes (LADD) as an immunotherapy platform for the treatment of cancer in several clinical trials in diverse indications. One LADD strain, known as CRS-207, has been engineered to express the tumor-associated antigen mesothelin and is being tested in pancreatic, ovarian and mesothelioma malignancies. Using multi-dimensional immunohistochemistry of paired biopsies from three patients with mesothelioma, we demonstrate the recruitment and expansion of effector tumor-infiltrating lymphocytes, including CD8+ T cells, mature DCs, CD163− macrophages and NK cells, following two prime infusions of CRS-207. In several different syngeneic mouse tumor models, we demonstrate that treatment with LADD engineered to express endogenous tumor antigens also induced significant changes in the TME that were consistent with changes observed in cancer patients, including enhanced CD8+ T cell effector function, recruitment of critical antigen presenting cells and reduction of regulatory T cells, and these changes correlated with significant therapeutic benefit in the mouse. LADD-induced changes to the TME were required for synergistic therapeutic antitumor efficacy combined with immune checkpoint blockade, including targeting MC38 tumor-specific neoantigens. Together, these findings demonstrate that intravenous administration of recombinant LADD therapy induces favorable changes in the tumor microenvironment in mice and humans with promise for effective outcomes in human clinical trials.

Citation Format: Weiwen Deng, Takahiro Tsujikawa, Nitya Nair, Thomas Hudson, Weiqun Liu, Chris S. Rae, Edward E. Lemmens, Anthony W. Desbien, William Hanson, Peter Lauer, Lisa M. Coussens, Dirk G. Brockstedt, Thomas W. Dubensky, Jr., Meredith L. Leong. Favorable changes in tumor microenvironment following intravenous dosing with live attenuated Listeria monocytogenes-based immunotherapy [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A013.

Trim32 Deficiency Enhances Th2 Immunity and Predisposes to Features of Atopic Dermatitis

Altered innate immunity is a feature of certain skin inflammatory diseases such as psoriasis and atopic dermatitis (AD). In this study, we provide evidence that deficiency in Trim32 (a tripartite motif [TRIM] protein with innate antiviral activity) contributes to a T helper type 2 biased response and predisposes to features of AD in mice. On treatment with the toll-like receptor 7 agonist imquimod (IMQ), Trim32 knockout mice displayed compromised psoriasiform phenotypes and defective T helper type 17 response. Instead, IMQ treatment of Trim32 knockout mice induced AD-like phenotypes with enhanced skin infiltration of eosinophils and mast cells, elevation of T helper type 2 cytokines/chemokines expression, and reduced expression of filaggrin protein expression. Furthermore, although the induction of phosphorylated Stat3 and RelA was compromised after IMQ treatment in the knockout mice, phosphorylated Stat6 was elevated. CC chemokine ligand 20 induction by tumor necrosis factor-α and IL-17A was reduced in Trim32-deficient keratinocytes, whereas CC chemokine ligand 5 induction by tumor necrosis factor-α and IL-4 was enhanced. In addition, Trim32 protein levels were elevated in mice treated with IMQ. Unlike Trim32 overexpression in psoriasis, TRIM32 levels were low in patients with AD. Based on Trim32 induction by IMQ, the lower levels of TRIM32 in AD skin compared with healthy control and psoriatic skin suggest a defective TRIM32 pathway in AD pathogenesis.