Number Of Tumor-infiltrating CD8 Research Articles

MRI features and tumor-infiltrating CD8 + T cells-based nomogram for predicting meningioma recurrence risk

ObjectiveThis study was based on MRI features and number of tumor-infiltrating CD8 + T cells in post-operative pathology, in predicting meningioma recurrence risk.MethodsClinical, pathological, and imaging data of 102 patients with surgically and pathologically confirmed meningiomas were retrospectively analyzed. Patients were divided into recurrence and non-recurrence groups based on follow-up. Tumor-infiltrating CD8 + T cells in tissue samples were quantitatively assessed with immunohistochemical staining. Apparent diffusion coefficient (ADC) histogram parameters from preoperative MRI were quantified in MaZda. Considering the high correlation between ADC histogram parameters, we only chose ADC histogram parameter that had the best predictive efficacy for COX regression analysis further. A visual nomogram was then constructed and the recurrence probability at 1- and 2-years was determined. Finally, subgroup analysis was performed with the nomogram.ResultsThe risk factors for meningioma recurrence were ADCp1 (hazard ratio [HR] = 0.961, 95% confidence interval [95% CI]: 0.937 ~ 0.986, p = 0.002) and CD8 + T cells (HR = 0.026, 95%CI: 0.001 ~ 0.609, p = 0.023). The resultant nomogram had AUC values of 0.779 and 0.784 for 1- and 2-years predicted recurrence rates, respectively. The survival analysis revealed that patients with low CD8 + T cells counts or ADCp1 had higher recurrence rates than those with high CD8 + T cells counts or ADCp1. Subgroup analysis revealed that the AUC of nomogram for predicting 1-year and 2-year recurrence of WHO grade 1 and WHO grade 2 meningiomas was 0.872 (0.652) and 0.828 (0.751), respectively.ConclusionsPreoperative ADC histogram parameters and tumor-infiltrating CD8 + T cells may be potential biomarkers in predicting meningioma recurrence risk.Clinical relevance statementThe findings will improve prognostic accuracy for patients with meningioma and potentially allow for targeted treatment of individuals who have the recurrent form.

Tumor-infiltrating lymphocytes in patients undergoing esophagectomy following neoadjuvant DCF therapy.

Accumulating evidence suggests that expression levels of tumor-infiltrating (TI) cells may play a prognostic role in patients with esophageal cancer who have undergone esophagectomy. However, its effect on patients undergoing neoadjuvant docetaxel, cisplatin, and 5-fluorouracil (DCF) therapy followed by esophagectomy for esophageal squamous cell carcinoma (ESCC) remains unclear. Therefore, this study aimed to elucidate the prognostic impact of TI cells in patients who underwent esophagectomy following neoadjuvant DCF therapy. Overall, 81 patients with ESCC who underwent curative esophagectomy following neoadjuvant DCF therapy were included. The number of TI CD8+ cells was determined using light microscopy at ×400 in tumor invasive margins. Receiver operative characteristic curve was used to determine the cutoff values for mortality for continuous variables; the patients were separated into high and low TI CD8+ cell groups and their backgrounds and clinical outcomes were compared. Overall and relapse-free survival were significantly worse in the TI CD8+-low group than that in the TI CD8+-high group (p < 0.01). Multivariate analysis revealed that positive ypN (hazard ratio [HR], 3.12; 95% confidence interval [CI], 1.08-9.02) and low TI CD8+ cell levels (HR, 2.77; 95% CI, 1.31-5.85) were independent prognostic factors for overall survival. Furthermore, positive venous invasion (HR, 2.63; 95% CI, 1.29-5.35) and low TI CD8+ cell levels (HR, 2.77; 95% CI, 1.70-5.46) were significant prognostic factors for relapse-free survival. Low TI CD8+ cell level was a prominent prognostic factor for patients with ESCC undergoing neoadjuvant DCF therapy followed by esophagectomy.

Copy number loss of KDM5D may be a predictive biomarker for ATR inhibitor treatment in male patients with pulmonary squamous cell carcinoma.

A limited number of patients with lung squamous cell carcinoma (SCC) benefit clinically from molecular targeted drugs because of a lack of targetable driver alterations. We aimed to understand the prevalence and clinical significance of lysine-specific demethylase 5D (KDM5D) copy number loss in SCC and explore its potential as a predictive biomarker for ataxia-telangiectasia and Rad3-related (ATR) inhibitor treatment. We evaluated KDM5D copy number loss in 173 surgically resected SCCs from male patients using fluorescence in situ hybridization. KDM5D copy number loss was detected in 75 of the 173 patients (43%). Genome-wide expression profiles of the transcription start sites (TSSs) were obtained from 17 SCCs, for which the cap analysis of gene expression assay was performed, revealing that upregulated genes in tumors with the KDM5D copy number loss are associated with 'cell cycle', whereas downregulated genes in tumors with KDM5D copy number loss were associated with 'immune response'. Clinicopathologically, SCCs with KDM5D copy number loss were associated with late pathological stage (p = 0.0085) and high stromal content (p = 0.0254). Multiplexed fluorescent immunohistochemistry showed that the number of tumor-infiltrating CD8+ /T-bet+ T cells was lower in SCCs with KDM5D copy number loss than in wild-type tumors. In conclusion, approximately 40% of the male patients with SCC exhibited KDM5D copy number loss. Tumors in patients who show this distinct phenotype can be 'cold tumors', which are characterized by the paucity of tumor T-cell infiltration and usually do not respond to immunotherapy. Thus, they may be candidates for trials with ATR inhibitors.

Dose-Dependent Effects in Plasma Oncotherapy: Critical In Vivo Immune Responses Missed by In Vitro Studies.

Cold atmospheric plasma (CAP) generates abundant reactive oxygen and nitrogen species (ROS and RNS, respectively) which can induce apoptosis, necrosis, and other biological responses in tumor cells. However, the frequently observed different biological responses to in vitro and in vivo CAP treatments remain poorly understood. Here, we reveal and explain plasma-generated ROS/RNS doses and immune system-related responses in a focused case study of the interactions of CAP with colon cancer cells in vitro and with the corresponding tumor in vivo. Plasma controls the biological activities of MC38 murine colon cancer cells and the involved tumor-infiltrating lymphocytes (TILs). In vitro CAP treatment causes necrosis and apoptosis in MC38 cells, which is dependent on the generated doses of intracellular and extracellular ROS/RNS. However, in vivo CAP treatment for 14 days decreases the proportion and number of tumor-infiltrating CD8+T cells while increasing PD-L1 and PD-1 expression in the tumors and the TILs, which promotes tumor growth in the studied C57BL/6 mice. Furthermore, the ROS/RNS levels in the tumor interstitial fluid of the CAP-treated mice are significantly lower than those in the MC38 cell culture supernatant. The results indicate that low doses of ROS/RNS derived from in vivo CAP treatment may activate the PD-1/PD-L1 signaling pathway in the tumor microenvironment and lead to the undesired tumor immune escape. Collectively, these results suggest the crucial role of the effect of doses of plasma-generated ROS and RNS, which are generally different in in vitro and in vivo treatments, and also suggest that appropriate dose adjustments are required upon translation to real-world plasma oncotherapy.

Metformin enhances T lymphocyte anti-tumor immunity by increasing the infiltration via vessel normalization

Abnormal tumor vasculature blocks the extravasation of T lymphocytes into the tumor, thereby suppressing anti-tumor immunity. Recently, metformin has been shown to affect tumor vasculature and enhance T lymphocyte anti-tumor immunity. However, whether or how metformin affects T lymphocyte anti-tumor immunity via a vascular mechanism remains poorly understood. Herein, we show that a large number of CD8+ lymphocytes gathered in the peri-tumoral region, while very few infiltrated the tumor. Metformin administration increased the expression of anti-tumor immunity-associated genes and the number of tumor-infiltrating CD8+ lymphocytes. Injection of CD8 but not CD4 neutralization antibody into tumor-bearing mice significantly abrogated the anti-tumor effect of metformin. Critically, CD8+ lymphocytes were found to pass through the wall of perfused vessel. Further results of immunofluorescent staining showed that metformin greatly elevated tumor perfusion, which was accompanied by increased vascular maturity in the intratumoral region (ITR) but not peritumoral region (PTR). These findings provide evidence for the vascular mechanism involved in metformin-induced enhancement of T lymphocyte anti-tumor immunity. By remodeling the abnormal tumor vasculature, also called vessel normalization metformin increases vascular maturity and tumor perfusion, thus allowing more CD8+ lymphocytes to infiltrate the tumor.

Low-dose anti-VEGFR2 therapy promotes anti-tumor immunity in lung adenocarcinoma by down-regulating the expression of layilin on tumor-infiltrating CD8+T cells

PurposeOur study intended to explore how low-dose anti-angiogenic drugs affected anti-tumor immunity of tumor-infiltrating exhausted CD8+T cells and achieved better clinical response when combined with immunotherapy. We set out to find potential targets or predictive biomarker on CD8+T cells for immunotherapy.MethodsWe tested different doses of anti-VEGFR2 antibody combined with anti-PD1 antibody to treat LUAD in vivo and analyzed tumor-infiltrating CD8+T cells by flow cytometry. CD8+T cells overexpressing LAYN were co-cultured with LA795 cell lines to identify the function of LAYN in CD8+T cells. We also analyzed clinical samples from advanced LUAD patients treated with anti-angiogenesis therapy combined with immunotherapy.ResultsLow-dose anti-VEGFR2 antibody combined with anti-PD1 antibody treatment delayed tumor growth and prolonged the survival time of tumor-bearing mice. The number of tumor-infiltrating CD8+T cells was reduced and the expression of LAYN was down-regulated in tumor-infiltrating CD8+T cells in the low-dose anti-VEGFR2 combination group. It was found that LAYN inhibited the killing function of CD8+T cells. In patients with advanced LUAD who received anti-angiogenesis therapy combined with immunotherapy, the LAYN+CD8+T cell subpopulation in good responders was significantly higher than that in poor responders. Furthermore, we demonstrated the expression of LAYN was regulated by upstream transcription factor NR4A1.ConclusionLow-dose anti-VEGFR2 antibody combined with anti-PD1 antibody therapy promoted anti-tumor immunity and the downregulation of LAYN in tumor-infiltrating CD8+T cells played an important role in this process. These findings had implications for improving the efficacy of immune checkpoint blockade therapy and further optimized clinical treatment guidelines in advanced LUAD.

Clinical relevance of tertiary lymphoid structures in esophageal squamous cell carcinoma

BackgroundTertiary lymphoid structures (TLSs) have been reported to be involved in immune responses in many carcinomas. This study investigated the significance of TLSs in esophageal squamous cell carcinoma, focusing on TLS maturation. MethodsThe relationships of TLSs with clinicopathological features of 236 patients who underwent curative surgery for stage 0-IV esophageal squamous cell carcinoma were investigated. Mature TLSs, in which the germinal center formation was rich in CD23+ cells, were classified as TLSs containing a germinal center (GC-TLSs). GC-TLS densities were measured, and CD8+ cells were counted. The prognostic impact of GC-TLSs was assessed by Kaplan–Meier plots using the log-rank test for the relapse-free survival. A comparative study of GC-TLSs was performed using the Wilcoxon rank sum test. The relationship between GC-TLSs and CD8+ cells was examined by Spearman’s rank correlation coefficient test.ResultsTLSs were located mainly at the invasive margin of the tumor in cases with esophageal squamous cell carcinoma. Among the patients treated with neoadjuvant chemotherapy, those with advanced disease had a better prognosis in the GC-TLS high-density group than did those in the GC-TLS low-density group. Patients in whom neoadjuvant chemotherapy was effective had more GC-TLSs than those in whom it was less effective. The density of GC-TLSs and the number of tumor-infiltrating CD8+ cells were higher in patients treated with neoadjuvant chemotherapy than in those without chemotherapy, and a weak correlation between the density of GC-TLSs and the number of tumor-infiltrating CD8+ cells was observed. Moreover, co-culturing of PBMCs with an anticancer drug-treated esophageal squamous cell carcinoma cell line increased the CD20 and CD23 expression in PBMCs in vitro.ConclusionTLS maturation may be important for evaluating the local tumor immune response in patients treated with neoadjuvant chemotherapy for esophageal squamous cell carcinoma. The present results suggest that TLS maturation may be a useful target for predicting the efficacy of immunotherapy, including immune checkpoint inhibitor treatment for esophageal squamous cell carcinoma.

The effects of T-DXd on the expression of HLA class I and chemokines CXCL9/10/11 in HER2-overexpressing gastric cancer cells

Trastuzumab deruxtecan (T-DXd), a HER2-targeting antibody–drug conjugate with a topoisomerase I inhibitor deruxtecan (DXd), exhibits an excellent anti-tumor effect in previously treated HER2-positive tumors. A recent study demonstrated that T-DXd not only suppressed tumor growth but also enhanced anti-tumor immunity through increasing the number of tumor-infiltrating CD8+ T cells and enhancement of major-histocompatibility-complex class I expression on tumor cells in a mouse model. However, the effect of T-DXd on anti-tumor immune responses in human cancers is largely unknown. We investigated the effect of T-DXd on the expression of HLA class I and CXCL9/10/11, T-cell chemoattractants, in HER2-positive human gastric cancer (GC) cells. We found that T-DXd significantly inhibited GC cell proliferation in a HER2-dependent manner, while it slightly increased the expression of HLA class I in HER2-positive GC cells. Moreover, we revealed that T-DXd significantly induced mRNA expression of CXCL9/10/11 in HER2-positive GC cells. T-DXd-triggered up-regulation of these chemokines was mediated through the activation of DNA damage signaling pathways. These results suggest that T-DXd triggers anti-tumor immune responses at least in part through induction of the expression of HLA class I and CXCL9/10/11 on HER2-positive GC cells, resulting in the enhancement of anti-tumor immunity in human GC.

FHOD1 and FMNL1 formin proteins in intestinal gastric cancer: correlation with tumor-infiltrating T lymphocytes and molecular subtypes

BackgroundGastric cancer (GC) is the third most common cause of cancer death. Intestinal type GC is a molecularly diverse disease. Formins control cytoskeletal processes and have been implicated in the progression of many cancers. Their clinical significance in GC remains unclear. Here, we characterize the expression of formin proteins FHOD1 and FMNL1 in intestinal GC tissue samples and investigate their association with clinical parameters, GC molecular subtypes and intratumoral T lymphocytes.MethodsThe prognostic significance of FHOD1 and FMNL1 mRNA expression was studied with Kaplan–Meier analyses in an online database. The expression of FHOD1 and FMNL1 proteins was characterized in GC cells, and in non-neoplastic and malignant tissues utilizing tumor microarrays of intestinal GC representing different molecular subtypes. FHOD1 and FMNL1 expression was correlated with clinical parameters, molecular features and T lymphocyte infiltration. Immunohistochemical expression of neither formin correlated with survival.ResultsKaplan–Meier analysis associated high FHOD1 and FMNL1 mRNA expression with reduced overall survival (OS). Characterization of FHOD1 and FMNL1 in GC cells showed cytoplasmic expression along the actin filaments. Similar pattern was recapitulated in GC tissue samples. Elevated FMNL1 was associated with larger tumor size and higher disease stage. Downregulation of FHOD1 associated with TP53-mutated GC tumors. Tumor cell FHOD1 expression strongly correlated with high numbers of tumor-infiltrating CD8 + lymphocytes.ConclusionsFHOD1 and FMNL1 proteins are expressed in the tumor cells of intestinal GC and significantly associate with clinical parameters without direct prognostic significance. FHOD1 correlates with high intratumoral CD8 + T lymphocyte infiltration in this cohort.

Tumor cell PD-L1 expression is a strong predictor of unfavorable prognosis in immune checkpoint therapy-naive clear cell renal cell cancer

BackgroundPD-L1 expression predicts response to immune checkpoint inhibitors in renal cell carcinomas (RCC), but has also been suggested to be linked to poor patient outcome.MethodsWe analyzed PD-L1 in > 1400 RCC in a tissue microarray format by immunohistochemistry. Results were compared with histological tumor type, parameters of cancer aggressiveness, and intratumoral CD8+ cytotoxic cells.ResultAt a cut-off level of 5% PD-L1 positive tumor cells, PD-L1 positivity was seen in 6.3% of 633 clear cell RCC (ccRCC), 18.2% of 165 papillary RCC, 18.8% of 64 chromophobe RCC, and 41.7% of 103 oncocytomas. In ccRCC, PD-L1 positivity was significantly linked to high ISUP (p < 0.0001), Fuhrman (p < 0.0001), Thoenes grade (p < 0.0001), distant metastasis (p = 0.0042), short recurrence-free (p < 0.0001), and overall survival (p = 0.0002). Intratumoral CD8+ lymphocytes were more frequent in PD-L1 positive (1055 ± 109) than in PD-L1 negative ccRCC (407 ± 28; p < 0.0001). PD-L positive immune cells were seen in 8.2% of all RCC and 13.9% of papillary RCC. In ccRCC, PD-L1 positive immune cells were linked to high numbers of tumor-infiltrating CD8+ cells (p < 0.0001), high ISUP (p < 0.0001), Fuhrman (p = 0.0027), and Thoenes grade (p < 0.0001), and poor tumor-specific survival (p = 0.0280).ConclusionsThese data suggest that PD-L1 expression in highly immunogenic RCCs facilitates immune evasion and contributes to cancer aggressiveness.

Telomerase-specific oncolytic immunotherapy for promoting efficacy of PD-1 blockade in osteosarcoma.

Immune checkpoint inhibitors including anti-programmed cell death 1 (PD-1) antibody have recently improved clinical outcome in certain cancer patients; however, osteosarcoma (OS) patients are refractory to PD-1 blockade. Oncolytic virotherapy has emerged as novel immunogenic therapy to augment antitumor immune response. We developed a telomerase-specific replication-competent oncolytic adenovirus OBP-502 that induces lytic cell death via binding to integrins. In this study, we assessed the combined effect of PD-1 blockade and OBP-502 in OS cells. The expression of coxsackie and adenovirus receptor (CAR), integrins αvβ3 and αvβ5, and programmed cell death ligand 1 (PD-L1) was analyzed in two murine OS cells (K7M2, NHOS). The cytopathic activity of OBP-502 in both cells was analyzed using the XTT assay. OBP-502-induced immunogenic cell death was assessed by analyzing the level of extracellular ATP and high-mobility group box protein B1 (HMGB1). Subcutaneous tumor models for K7M2 and NHOS cells were used to evaluate the antitumor effect and number of tumor-infiltrating CD8+ cells in combination therapy. K7M2 and NHOS cells showed high expression of integrins αvβ3 and αvβ5, but not CAR. OBP-502 significantly suppressed the viability of both cells, in which PD-L1 expression and the release of ATP and HMGB1 were significantly increased. Intratumoral injection of OBP-502 significantly augmented the efficacy of PD-1 blockade on subcutaneous K2M2 and NHOS tumor models via enhancement of tumor-infiltrating CD8+ T cells. Our results suggest that telomerase-specific oncolytic virotherapy is a promising antitumor strategy to promote the efficacy of PD-1 blockade in OS.

Abstract 2267: MEDI5083, a novel CD40L-Fc fusion protein, activates the CD40 pathway on antigen-presenting cells and promotes robust anti-tumor immune responses in both hot and cold murine tumor models

Abstract Background: While diverse strategies may boost anti-tumor immunity, of significant interest are therapeutic approaches that are efficacious in tumors with high and low immune cell infiltration. Targeting CD40 with its natural ligand (CD40L) augments the immune-stimulatory function of antigen-presenting cells and enhances T cell priming, making this an attractive means of promoting anti-tumor responses. MEDI5083 is a novel fusion protein containing a hexameric recombinant human CD40L structure covalently linked to human IgG4p Fc. Here, we present preclinical functional characterization of MEDI5083. Methods MEDI5083 functionality was first established using several in vitro approaches with human cell lines and primary human cells. To examine anti-tumor activity in vivo, we constructed a murine surrogate (mCD40L-Fc) with similar physical and target-binding properties to those of MEDI5083. The effects of mCD40L-Fc on immune cell activation and tumor growth were determined in the immunologically cold B16F10 model of melanoma and the immunologically hot CT26 model of colon carcinoma. Results: MEDI5083 specifically bound to human CD40, triggered its internalization, and robustly stimulated CD40 signaling as measured by NF-κB activation in Ramos and THP-1 cells. MEDI5083 potently upregulated expression of MHCII and the co-stimulatory molecules CD80 and CD86 on primary human B cells and myeloid cells, while inducing secretion of pro-inflammatory cytokines. MEDI5083 also enhanced secretion of IFN-γ by memory CD8+ T cells in an antigen-recall assay. In the B16F10 model, repeated mCD40L-Fc dosing significantly decreased tumor growth. Consistent with enhancing immune cell activation and T cell priming, mCD40L-Fc treatment elevated serum levels of IL-12 and IFN-γ, and increased numbers of tumor-infiltrating CD8+ T cells. While this model responds poorly to checkpoint blockade, co-administration of mCD40L-Fc with anti-PD-L1 antibody demonstrated additivity, consistent with PD-1/PD-L1-mediated regulation of mCD40L-Fc-driven adaptive immunity. Repeated dosing of mCD40L-Fc in the CT26 model inhibited tumor growth. Treatment was associated with diminished tumor-infiltrating Treg numbers, increased CD8+ T cell:Treg ratios, and phenotypic changes in tumor-infiltrating immune cells. Tumor supernatants exhibited increased IFN-γ, consistent with enhanced anti-tumor immunity. Rechallenge of mice with complete tumor regression confirmed generation of durable memory. Conclusions: We have demonstrated that stimulation of CD40 signaling with MEDI5083 or mCD40L-Fc leads to robust activation of immune cells and enhanced adaptive immune responses. In vivo, this translates to enhanced control of both poorly- and well-infiltrated syngeneic tumors and generation of durable memory in mice with complete tumor regression. Citation Format: Deepali Malhotra, Sean Turman, Kelly McGlinchey, Yaya Wang, Yue Wang. MEDI5083, a novel CD40L-Fc fusion protein, activates the CD40 pathway on antigen-presenting cells and promotes robust anti-tumor immune responses in both hot and cold murine tumor models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2267.

Abstract 2260: Radiotherapy enhances newly infiltrating CD8+T cells into tumor tissue to increase intratumor CD8+T cells and exert an anti-tumor effects

Abstract Background: The enhancement of antitumor immune response with radiotherapy was reported recently, but there are few reports on the mechanism of the effect in rectal cancer. In neoadjuvant chemoradiotherapy (NACRT) for rectal cancer, we reported that CD8+T cells in tumor tissues were highly induced and the density of CD8+T cells were a favorable prognostic factor. The aim of the present study was to elucidate the dynamics of CD8+T cells in the tumor after irradiation. Methods: For this purpose, we established a therapeutic model of irradiation for BALB/c mice inoculated with CT26 colon cancer cell line. They are irradiated with a single dose of 10Gy after 14 days. We analyzed CD8+ T cells infiltration of both irradiated (mice) and no treated (control) mice by flow cytometry. Intratumor CD8+ T cells were fractionated into three populations according to the expression of PD-1 and Tim-3. The numbers and ratios were measured and their dynamics were analyzed. Next, purified CD8+T cells from the tumor with or without irradiation and intracellular cytokines such as IFNγ, TNF-α, and IL-2 were measured. Finally, we analyzed mice treated with FTY720 to test newly infiltrating T cell infiltration after irradiation delivered locally into tumors. Results: In our model, elevated numbers of tumor-infiltrating CD8+ T cells between day11 and day18 after irradiation were observed in tumors of mice compared to control. We observed that the number of PD-1+Tim-3+ CD8+ T cells, that comprised the major population among intratumoral CD8+ T cells, were markedly increasing in irradiated mice. Functionally, intratumoral CD8+ T cells in irradiated mice produced more INF-γ compared to control. Especially, PD-1+Tim-3+ CD8+ T cells enhanced INF-γ production. Among the three populations, PD-1+Tim-3+ CD8+ T cells contained the largest fraction of effector memory (CD44hiCD62Llow) cells, but the lowest fraction of central memory (CD44hiCD62Lhi) cells. Finally, after administration of FTY-720, the decrease rate of intratumoral CD8+ T cells in irradiated mice was much higher than in control. This results suggest that newly infiltrating CD8+ T cell number in irradiated mice was higher than in control. Conclusions: In mouse model of irradiation, there were newly infiltrating CD8+ T cells which was markedly increased compared to the control. This population may be involved in the increase of intratumor CD8+ T cells and may contribute to antitumor effects. This change is expected to trigger further therapeutic intervention. Citation Format: Kimihiro Yamashita, EIJI Fukuoka, Yutaka Sugita, Akira Arimoto, Akihiro Watanabe, Gousuke Takiguchi, Naoki Urakawa, Hiroshi Hasegawa, Masashi Yamamoto, Shingo Kanaji, Yoshiko Matsuda, Takeru Matsuda, Takeru Matsuda, Taro Oshikiri, Tetsu Nakamura, Satoshi Suzuki, Yoshihiro Kakeji. Radiotherapy enhances newly infiltrating CD8+T cells into tumor tissue to increase intratumor CD8+T cells and exert an anti-tumor effects [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2260.

Abstract 917: Functional blocking of CD5 on T cells to enhance the efficacy of therapeutic PD-1 blockade in treatment of mouse 4T1 breast tumors

Abstract Blockade of programmed cell death protein 1 (PD-1) is approved for treatment of multiple human cancers and is the focus of multiple studies due to its key role in T cell function. However, only patients with ‘'hot'' tumors (i.e. those with increased numbers of tumor-infiltrating CD8+ T cells) respond well to the blockade. This suggests that new strategies to increase infiltration of CD8+ T cells into tumors will increase the number of tumor types and patients benefiting from anti-PD-1 therapy. CD5, a member of the scavenger receptor cysteine-rich (SRCR) superfamily, is expressed on T cells and a subset of B cells (B1a). It can attenuate TCR signaling and impair cytotoxic T lymphocyte (CTL) activation. CD5 knockout mice have increased anti-tumor immunity and reduced homograft tumor growth: reducing CD5 on CTLs may be therapeutically beneficial to enhance the anti-tumor response and increase tumor-infiltrating CD8+ T cells. We report that in vivo administration of anti-CD5 blocking MAb treatment increased primary T cell activation in response to 4T1 tumor cell homografts and ex vivo activation as measured by increased CD69, Fas, Fas ligand, IFNγ, PD-1, and apoptosis. Further, anti-CD5 treatment enhanced the capacity of primary T cells to kill 4T1 tumor cells ex vivo. Mice receiving anti-CD5 and anti-PD-1 in combination exhibited increased overall survival compared to mice treated with either agent alone. These data support the potential of blockade of CD5 function to enhance T cell-mediated anti-tumor immunity and PD-1 blockade treatment. Citation Format: Faizah Alotaibi, Mateusz Rytelewski, Rene Figueredo, Ronak Zareardalan1, Saman Maleki Vareki, Xiufen Zheng, Meng Zhang, Peter Ferguson, Mikal El-Hajjar, Yousef Najajreh, Wei-ping Min, James Koropatnick. Functional blocking of CD5 on T cells to enhance the efficacy of therapeutic PD-1 blockade in treatment of mouse 4T1 breast tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 917.

Cutting Edge: Antitumor Immunity by Pathogen-Specific CD8 T Cells in the Absence of Cognate Antigen Recognition.

Cancer prognosis often correlates with the number of tumor-infiltrating CD8 T cells, but many of these cells recognize pathogens that commonly infect humans. The contribution of pathogen-specific "bystander" CD8 T cells to antitumor immunity remains largely unknown. Inflammatory cytokines are sufficient for memory CD8 T cell activation and gain of effector functions, indicating tumor-derived inflammation could facilitate pathogen-specific CD8 T cells to participate in tumor control. In this study, we show in contrast to tumor-specific CD8 T cells that pathogen-specific primary memory CD8 T cells inside tumor were not able to exert their effector functions and influence tumor progression. However, infection-induced memory CD8 T cells with defined history of repeated Ag encounters (i.e., quaternary memory) showed increased sensitivity to tumor-derived inflammation that resulted in activation, gain of effector functions, and better control of tumor growth. Thus, memory CD8 T cells with heightened ability to recognize environmental inflammatory stimuli can contribute to antitumor immunity in the absence of cognate Ag recognition.

Caveolin-2 deficiency induces a rapid anti-tumor immune response prior to regression of implanted murine lung carcinoma tumors

Immunosuppression is critical for tumor growth and metastasis as well as obstacle to effective immunotherapy. Here, we demonstrate that host deficiency in caveolin-2, a member of caveolin protein family, increases M1-polarized tumor-associated macrophage (TAM) and CD8 T cell infiltration into subcutaneously implanted murine lung carcinoma tumors. Importantly, increase in M1 TAM-specific markers and cytokines occurs prior to increased numbers of tumor-infiltrating CD8 T cells and tumor regression in caveolin-2 deficient mice, suggesting that an early increase in M1 TAMs is a novel mechanism, via which host deficiency in caveolin-2 inhibits tumor growth. Consistent with the latter, transfer and co-injection of caveolin-2 deficient bone marrow (origin of TAMs) suppresses tumor growth and increases numbers of M1-polarized TAMs in wild type mice. Collectively, our data suggest that lung cancer cells use caveolin-2 expressed in bone marrow-derived cell types including TAMs to promote tumor growth via suppressing the anti-tumor immune response and that caveolin-2 could be a potential target for cancer immunotherapy.

Abstract LB-B11: Myeloid p38 MAPK promotes tumorigenesis by suppressing cytotoxic T cell recruitment

Abstract The last decade has seen explosive progress in understanding how tumor-associated macrophages (TAM) contribute to the development, metastasis, and therapy resistance of cancer. TAM and their molecular components are investigated as targets for cancer therapy. However, the precise mechanisms for their function remain to be fully elucidated. The p38 MAP kinase is known to play a pivotal role in cellular responses to stress, mitogenic stimuli, and immune signaling. Evidence from clinical observations and cell culture experiments reveals a role for p38 in many aspects of cancer and immunity. However, little is known about the functions of p38alpha, the most abundant and ubiquitously expressed p38 isoform, in TAM. Here we found that myeloid-specific p38alpha ablation resulted in a decrease in tumor incidence and multiplicity in a DMBA-TPA carcinogenesis model. Tumors from these mutant mice displayed markedly reduced proliferation and poorly developed blood vessels compared to those from control WT mice. Genome-wide expression analysis revealed that p38alpha ablation in macrophages resulted in enhanced CXCL9 expression, a chemokine crucial for cytotoxic T cell recruitment. Indeed, we observed greater number of tumor-infiltrating CD8+ T cells in myeloid-specific p38alpha-knockout mice. p38alpha indel mutations in THP-1 cells also led to elevated CXCL9 induction. TCGA data analysis revealed that higher intratumoral expression of CXCL9 was associated with prolonged survival of cancer patients, suggesting a beneficial effect of CXCL9 in human cancers. Next, we sought to identify the molecular mechanism linking p38alpha to the regulation of CXCL9 expression, and found that p38alpha directly phosphorylates and enables the induction of ATF3, a transcription factor that represses CXCL9 expression. Consistent with this finding, ATF3-deficient macrophages exhibited higher CXCL9 expression similar to p38alpha-deficient macrophages. Therefore, macrophage-specific targeting of p38alpha signaling may promote cytotoxic T cell recruitment to the tumor microenvironment and maximize the potential of checkpoint inhibitor and CAR T cell therapies and other therapeutic modalities that rely on tumor-killing CD8+ T cells. Citation Format: Min-Kyung Choo, Jin Mo Park. Myeloid p38 MAPK promotes tumorigenesis by suppressing cytotoxic T cell recruitment [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr LB-B11. doi:10.1158/1535-7163.TARG-19-LB-B11

Significance of Herpesvirus Entry Mediator Expression in Human Colorectal Liver Metastasis.

Herpesvirus entry mediator (HVEM) has been suggested to play various roles in cancer biology. The authors report that HVEM expression in tumor cells is associated with a reduction in the number of tumor-infiltrating lymphocytes and a poor prognosis after surgical resection in various human gastrointestinal cancers. This study aimed to clarify the clinical significance of HVEM expression in human colorectal liver metastasis (CRLM). This study examined the cases of 104 patients with CRLM who underwent curative liver resection at Nara Medical University between 2000 and 2014. The median follow-up period was 50.2months. Immunohistochemical staining was performed using antibodies against HVEM, CD4, CD8, and CD45RO. High HVEM expression was observed in 49 patients (47.1%) with CRLM. Expression of HVEM was not associated with age, gender, administration of preoperative chemotherapy, tumor size, number of tumors, or histologic differentiation. The high-HVEM group exhibited significantly worse overall survival (OS) than the low-HVEM group (P = 0.002). Multivariate analysis showed that high HVEM expression in CRLM, age of 70years or older, and having five or more tumors are independent poor prognostic factors for OS (hazard ratio [HR], 3.35; 95% confidence interval [CI], 1.41-7.93; P = 0.006). The number of tumor-infiltrating CD8+ and CD45RO+ T cells was significantly lower in the high-HVEM group than in the low-HVEM group. High HVEM expression in primary colorectal cancer was significantly associated with synchronous CRLM, but not with metachronous CRLM. Tumor HVEM expression might play a critical role in CRLM.

Abstract 4852: Boosting immunity against pancreatic cancer by OBP-702 (Pfifteloxin), telomerase-specific replicative adenovirus armed with wild-type p53 gene

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is the most lethal disease with a 5-year survival rate of less than 10%. Although immune checkpoint blockade has recently emerged as a novel antitumor therapy, PDAC is less sensitive to immunotherapy due to small number of tumor-infiltrating T cells. Recently, oncolytic virotherapy has been shown to stimulate the immune system as an immunogenic antitumor therapy. Activation of p53 has been also known to enhance antitumor immunity. In this study, we investigated the potential of telomerases-specific p53-expressing oncolytic adenovirus (OBP-702, Pfifeteloxin) for inducing the immunogenic cell death in PDAC cells. Methods: OBP-702 (Pfifteloxin) is a telomerase-specific oncolytic adenovirus, in which the human telomerase reverse transcriptase (hTERT) promoter drives the expression of the viral E1 gene for tumor-specific replication, that expresses the wild-type p53 by inserting the human p53 cDNA at the deleted E3. OBP-301 (Telomelysin) is an original telomerase-specific adenovirus lacking p53. OBP-502 is an RGD mutant fiber-containing OBP-301. We used 4 human PDAC cell lines (MIA PaCa-2, Capan-1, BxPC-3, Panc-1) and mouse PDAC cell line (Pan02). In vitro antitumor effect of these viruses was evaluated using a XTT assay. The molecular mechanism of virus-mediated cell death was investigated by western blot analysis. The virus-induced immunogenic cell death was assessed by analyzing the level of extracellular ATP and high-mobility group box protein B1 (HMGB1) using ELISA assay. The comparative in vivo antitumor efficacy was also investigated using a syngeneic Pan02 subcutaneous tumor model. Results: Telomerase-specific oncolytic adenoviruses induced the antitumor effect in all PDAC cells in a dose-dependent manner. The antitumor effect of OBP-702 was superior to that of OBP-301 or OBP-502. OBP-301 and OBP-502 mainly induced autophagy, whereas OBP-702 induced autophagy and apoptosis at 72 h after infection. The concentration of extracellular ATP and HMGB1 was significantly increased in OBP-702-infected PDAC cells compared to OBP-301- or OBP-502-infected cells at 24 and 48 h after infection. In mice carrying subcutaneous Pan02 murine PDAC tumors, intratumoral injection of OBP-702 resulted in a significant inhibition of tumor growth. Moreover, the number of tumor-infiltrating CD8+ T cells was significantly increased in OBP-702-treated groups compared to mock-treated group. Conclusion: Our data suggest that telomerases-specific p53-expressing oncolytic adenovirus OBP-702 (Pfifteloxin) induces profound immunogenic cell death to boost the immune responses in PDAC. Clinical trials with OBP-702 and immune checkpoint inhibitors for PDAC are warranted. Citation Format: Hiroyuki Araki, Hiroshi Tazawa, Takuro Fushimi, Takeyoshi Nishiyama, Satotu Kikuchi, Shinji Kuroda, Ryuichi Yoshida, Hiroyuki Kishimoto, Masahiko Nishizaki, Yasuo Urata, Shunsuke Kagawa, Toshiyoshi Fujiwara. Boosting immunity against pancreatic cancer by OBP-702 (Pfifteloxin), telomerase-specific replicative adenovirus armed with wild-type p53 gene [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 4852.

Abstract 3231: Oncolytic immunotherapy with PD-1 blockade and telomerase-specific oncolytic adenovirus in osteosarcoma

Abstract Background: Osteosarcoma (OS) is the most frequent primary malignant tumor of bone in children and adolescents. Although immune checkpoint inhibitor, anti-programmed death protein 1 (PD-1) antibody, has dramatically improved the clinical outcome in some cancer patients, OS patients are less sensitive to PD-1 blockade due to poor immune responses. Recently, oncolytic virotherapy has been shown to stimulate the immune system through induction of immunogenic cell death (ICD). We recently developed a RGD fiber-modified telomerase-specific oncolytic adenovirus OBP-502, which can enter into tumor cells by binding to cell surface integrin and induce oncolytic cell death in a telomerase-dependent manner. In this study, we assessed the in vitro and in vivo antitumor efficacy of combination therapy with PD-1 blockade and OBP-502 in OS cells. Methods: We used 2 murine OS cell lines, K7M2 and NHOS. The expression of PD-L1, coxsackie and adenovirus receptor (CAR), and integrin on the cell surface was analyzed by flow cytometric analysis. We analyzed the in vitro antitumor effect of OBP-502 using XTT assay and western blot analysis. Virus-induced ICD was assessed by analyzing the level of extracellular ATP and high-mobility group box protein B1 (HMGB1). To evaluate the therapeutic potential of oncolytic immunotherapy, we investigated the in vivo antitumor effect of combination therapy with anti-PD-1 antibody and OBP-502 using a subcutaneous K7M2 xenograft tumor model. Moreover, the number of tumor-infiltrating CD8+, CD4+ and Foxp3+ T cells was analyzed by immunohistochemistry. Results: Flow cytometric analysis demonstrated that K7M2 and NHOS cells had the expression of PD-L1 and integrin, but not CAR. XTT assay showed that OBP-502 efficiently suppressed the viability of K7M2 and NHOS cells in a dose-dependent manner. Western blot analysis revealed that OBP-502 induced the apoptosis-related cell death in K7M2 and NHOS cells. ELISA assay demonstrated that OBP-502 significantly increased the level of extracellular ATP and HMGB1 in K7M2 and NHOS cells. In vivo experiment using a subcutaneous K7M2 xenograft tumor model showed that combination of anti-PD-1 antibody and OBP-502 significantly reduced tumor growth compared to mock treatment or monotherapy. Immunohistochemical analysis revealed that OBP-502 significantly increased the number of tumor-infiltrating CD8+ T cells compared to mock treatment or monotherapy. By contrast, OBP-502 did not affect the number of CD4+ and Foxp3+ T cells in tumor tissues. Conclusion: These results suggest that oncolytic immunotherapy with PD-1 blockade and telomerase-specific oncolytic adenovirus is a promising antitumor strategy to promote the therapeutic potential of PD-1 blockade in OS through stimulation of antitumor immune response. Citation Format: Koji Demiya, Hiroshi Tazawa, Yusuke Mochizuki, Miho Kure, Joe Hasei, Toshiyuki Kunisada, Yasuo Urata, Toshifumi Ozaki, Toshiyoshi Fujiwara. Oncolytic immunotherapy with PD-1 blockade and telomerase-specific oncolytic adenovirus in osteosarcoma [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 3231.