Foxp3-positive Cells Research Articles

Relationship Between Dysbiotic Wound Microbiota and Critical Colonization: Involvement of FOXP3-Positive Cells in Rats.

Detection of critical colonization is gaining importance in wound management, but its pathophysiology remains unclear. We previously clarified that a dysbiotic wound microbiota differing from skin commensal microbiota may be involved in critical colonization and that such wounds contain fewer Forkhead box protein P3 (FOXP3)-positive cells in the tissue. However, it is not clear whether FOXP3-positive cells contribute to the development of critical colonization. Here, we examined whether inhibition of FOXP3-positive cell could induce critical colonization when the commensal microbiota was present in the wounds. Sprague-Dawley rats were administered FK506 or vehicle to inhibit differentiation into FOXP3-positive cells. Full-thickness wounds were made on the dorsal skin and inoculated with bacterial solution (dysbiosis group) or Luria-Bertani medium (commensal group). A bacterial solution was prepared by anaerobically culturing bacteria from the skin of donor rats on an artificial dermis in Luria-Bertani medium for 72 hours. Tissues were collected on day 4 postwounding for histological evaluation. After microbiota transplantation, excessive inflammation occurred in the FK506 + commensal group. In contrast, wounds with transplanted dysbiotic microbiota showed the same level of neutrophil infiltration, regardless of FK506 administration. Furthermore, the wound area was larger in the FK506 + commensal group than in the vehicle + commensal group on day 4 postwounding ( P = 0.01). This area was also significantly larger in both the vehicle + dysbiosis ( P = 0.01) and FK506 + dysbiosis groups ( P = 0.03) than in the vehicle + commensal group. This study has shown that dysbiosis may be at least related to developing critical colonization, and the results suggest that FOXP3-positive cells are involved in this process. Our study may contribute to establishing new interventions that prevent critical colonization by correcting wound microbiota.

Non-cell-autonomous suppression of tumor growth by RECK in immunocompetent mice.

RECK is a candidate tumor suppressor gene isolated as a gene that induces flat reversion in a cell line transformed by the KRAS oncogene. Since RECK knockout mice die in utero, they are not suitable for studying the effects of RECK on tumor formation. In this study, we found an increased incidence of spontaneous pulmonary adenomas in mice with reduced RECK expression (RECK-Hypo mice). To evaluate the effects of RECK expressed by either tumor cells or host cells on tumor growth, we established a tumorigenic cell line (MKER) from the kidney of a C57BL/6 mouse and performed syngeneic transplantation experiments. Our results indicate that when RECK expression is low in host cells, transplanted MKER cells grow faster and kill the animal more rapidly. Since RECK is required for the formation of proper fibrillin fibers that serve as a tissue reservoir for precursors of TGFβ-family cytokines, we assessed the levels of TGFβ1 in the peripheral blood. We found a significant increase in TGFβ1 in RECK-Hypo mice compared to wild-type mice. We also found that the proportion of FOXP3-positive regulatory T (Treg) cells among splenocytes was higher in RECK-Hypo mice compared to the control mice. Furthermore, the number of FOXP3-positive cells in spontaneous hematopoietic neoplasms in the lungs as well as tumors that formed after MKER transplantation was significantly higher in RECK-Hypo mice compared to the control mice. These findings indicate that RECK-mediated tumor suppression involves a non-cell-autonomous mechanism and that possible roles of TGFβ1 and Treg cells in such a mechanism warrant further study.

Detailed Profiling of the Tumor Microenvironment in Ethnic Breast Cancer, Using Tissue Microarrays and Multiplex Immunofluorescence.

Breast cancer poses a global health challenge, yet the influence of ethnicity on the tumor microenvironment (TME) remains understudied. In this investigation, we examined immune cell infiltration in 230 breast cancer samples, emphasizing diverse ethnic populations. Leveraging tissue microarrays (TMAs) and core samples, we applied multiplex immunofluorescence (mIF) to dissect immune cell subtypes across TME regions. Our analysis revealed distinct immune cell distribution patterns, particularly enriched in aggressive molecular subtypes triple-negative and HER2-positive tumors. We observed significant correlations between immune cell abundance and key clinicopathological parameters, including tumor size, lymph node involvement, and patient overall survival. Notably, immune cell location within different TME regions showed varying correlations with clinicopathologic parameters. Additionally, ethnicities exhibited diverse distributions of cells, with certain ethnicities showing higher abundance compared to others. In TMA samples, patients of Chinese and Caribbean origin displayed significantly lower numbers of B cells, TAMs, and FOXP3-positive cells. These findings highlight the intricate interplay between immune cells and breast cancer progression, with implications for personalized treatment strategies. Moving forward, integrating advanced imaging techniques, and exploring immune cell heterogeneity in diverse ethnic cohorts can uncover novel immune signatures and guide tailored immunotherapeutic interventions, ultimately improving breast cancer management.

Prognostic Significance of T-Cells and Macrophages in the Tumour Microenvironment of Nodal DLBCL.

Revised International Prognostic (R-IPI) score is used widely for risk stratification of DLBCL cases, yet some patients belonging to same risk category tend to exhibit different outcomes. The role of T-cells and macrophages in prognostication of lymphomas has been a point of interest of late. We aimed to study the association of FOXP3 positive T-regulatory cells, cytotoxic T-cells and macrophages with the immunophenotypic subtypes, clinicopathological characteristics, treatment response and survival in nodal diffuse large B-cell lymphoma (DLBCL) patients. The clinicopathological and treatment data of 83 DLBCL patients diagnosed and treated at our institute from January 2015 to December 2018 were collected and followed up till June 2020. CD8, FOXP3 and CD68 immunostains were performed to highlight the cytotoxic T-cells, T-regulatory cells and macrophages respectively on the lymph node biopsies and the distribution of these cells and their association with clinico-pathological factors, treatment response and survival was analyzed. DLBCL cases with higher percentage of CD3 positive T-cells and CD8 positive cytotoxic T-cells had significant association with attainment of complete response to treatment. In addition, CD8 positive T-cells of more than 6.5% proved to be an independent predictor of treatment outcome (p = 0.022). Multivariate Cox regression survival analysis revealed that cases with 'good' R-IPI prognostic score and 'high CD68 positive macrophages in tumor microenvironment' had a significantly longer overall survival. Increased number of cytotoxic T-cells was significantly associated with complete response to treatment and higher number of macrophages correlated significantly with better overall survival signifying their antitumor effects.

Abstract 3806: Impact of tumor-infiltrating lymphocytes, tertiary lymphoid structures, and neutrophil-to-lymphocyte ratio on the prognosis of patients with lung metastases from uterine leiomyosarcoma

Abstract In the tumor microenvironment, tumor-infiltrating lymphocytes (TILs) and tertiary lymphoid structures (TLSs) are known to play a major role in terms of antitumor immunity. It has been reported that the presence of TILs and TLSs is related to the prognosis of various cancers. In addition, neutrophil-to-lymphocyte ratio (NLR) has also been associated with the prognosis in them. We investigated the significance of TILs, TLSs and NLR as a prognosis indicator for lung metastases from uterine leiomyosarcoma. We retrospectively recruited 102 patients undergoing metastasetomy for lung metastases from uterine leiomyosarcoma at Okayama University Hospital from January 2006 to December 2019. TILs were evaluated by immunohistochemical staining of surgically resected specimens of lung metastases using anti-CD3/CD8/CD103/Foxp3 antibodies. TLSs were also evaluated using anti-CD20 antibodies. We counted the number of CD3/CD8/CD103/Foxp3-positive cells and classified TILs into high and low groups. We measured the density of CD20-positive cells and classified TLSs into high- and low-density groups. NLR was calculated from the blood examination immediately before the most recent pulmonary metastasectomy. We determined the cut-off value for NLR using a time-dependent receiver operating characteristic (ROC) curve analysis and classified the patients into NLR-high and NLR-low groups according to the cut-off value. In terms of TILs, both CD3 and CD8 were correlated with the prognosis. The overall survival (OS) was significantly better in patients with CD3-high group (p = 0.018), CD8-high group (p = 0.017), TLSs-high group (p = 0.041) and NLR-low group (p = 0.018), respectively. The status of CD103 and Foxp3 did not affect the prognosis. We assessed the impact of the combination of CD8-positive TILs or TLSs and NLR on the prognosis. Regarding CD8-positive TILs and NLR, the OS of CD8-high/NLR-low group was significantly better than that of CD8-low/NLR-high group (p = 0.0078). In terms of TLSs and NLR, the OS of TLSs-high/NLR low group was significantly better than that of TLSs-low/NLR-high group (p = 0.010). In conclusion, CD3-positive TILs, CD8-positive TILs, TLSs, and NLR are correlated with the prognosis, respectively. The combination of CD8-positive TILs or TLSs and NLR may be indicators to predict the prognosis of the patients with lung metastases from uterine leiomyosarcoma. Citation Format: Fumiaki Mukohara, Naoki Matsuda, Hiromasa Yamamoto, Tomohiro Habu, Daisuke Mizuno, Ryo Yoshichika, Atsushi Matsuoka, Tomoaki Higashihara, Naohiro Hayashi, Mao Yoshikawa, Masayoshi Ohki, Kazuhiko Shien, Ken Suzawa, Katsuhito Takahashi, Shinichi Toyooka. Impact of tumor-infiltrating lymphocytes, tertiary lymphoid structures, and neutrophil-to-lymphocyte ratio on the prognosis of patients with lung metastases from uterine leiomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3806.

Simvastatin alleviates experimental autoimmune encephalomyelitis through regulating the balance of Th17 and Treg in mice.

The aim of this study was to elucidate the therapeutic effect of simvastatin on experimental autoimmune encephalomyelitis (EAE) by regulating the balance between Th17 and Treg cells in mice. C57BL/6 mice were randomly divided into four groups: normal group, EAE group, simvastatin (2 and 10 mg/kg) group, and AG490 group (with AG490 serving as the positive control). Neurological function scores of mice were assessed daily. The four groups received treatments of normal saline, normal saline, and simvastatin (2 and 10 mg/kg), respectively. In the AG490 group, mice were injected intraperitoneally with AG490 (1 mg) every other day, and treatment was halted after 3 weeks. The spinal cord was stained with hematoxylin and eosin (H&E), and immunohistochemical staining for retinoic acid receptor-related orphan receptor γ(RORγ) and Foxp3 (Foxp3) was performed. Spleen samples were taken for Th17 and Treg analysis using flow cytometry. The levels of interleukin-17 and transforming growth factor-β (TGF-β) were detected using enzyme-linked immunosorbent assay (ELISA). In the simvastatin and AG490 groups, recovery from neurological impairment was earlier compared to the EAE group, and the symptoms were notably improved. Both simvastatin and AG490 reduced focal inflammation, decreased RORγ-positive cell infiltration, and significantly increased the number of FOXP3-positive cells. The number of Th17 cells and the level of IL-17 in the spleen were decreased in the simvastatin and AG490 treatment groups, while the number of Treg cells and TGF-β levels were significantly increased across all treatment groups. Simvastatin exhibits anti-inflammatory and immunomodulatory effects, potentially alleviating symptoms of neurological dysfunction of EAE. Regulating the balance between Th17 and Treg may represent a therapeutic mechanism for simvastatin in treating EAE.

Identification of FOXP3+ epithelial cells contributing to pancreatic proliferation and angiogenesis.

Forkhead box protein 3 (FOXP3), traditionally recognized as a specific transcription factor for regulatory T cells (Tregs), has also been identified in various tumor epithelial cells (named as cancer-FOXP3, c-FOXP3). However, the natural state and functional role of FOXP3 positive tumor epithelial cells remain unknown. Monoclonal cells expressing varying levels of c-FOXP3 were isolated from established PANC-1 cells using limited dilution. Whole transcriptome sequencing and weighted gene co-expression network analysis (WGCNA) were conducted on these subsets, followed by in vitro and in vivo functional investigations. In addition, we identified c-FOXP3+E-cadherin- epithelial cells in human pancreatic cancer tissues after radical resection by immunofluorescence co-staining. We also investigated the connection between c-FOXP3+E-cadherin- epithelial cells and their clinicopathological features. Our study uncovered a distinct subset of c-FOXP3+ tumor epithelial cells characterized by reduced E-cadherin expression. C-FOXP3+E-cadherin- cells displayed significant proliferation potential and pro-angiogenic effect through the expression of chemokines, including C-X-C motif ligand 1 (CXCL1), C-X-C motif ligand 5 (CXCL5), and C-X-C motif ligand 8 (CXCL8). Notably, higher counts of c-FOXP3+E-Cadherin- cells correlated with poorer prognosis, lower tumor differentiation, lymph node metastasis, and vascular invasion in pancreatic ductal adenocarcinoma (PDAC). In conclusion, this work revealed the stable expression of FOXP3 in tumor epithelial cells, marking a distinct subset. C-FOXP3+E-cadherin- epithelial cells exhibit active proliferation and promote angiogenesis in a vascular endothelial growth factor A (VEGFA) independent manner. These findings provide novel insights into PDAC prognosis and therapeutic avenues.NEW & NOTEWORTHY In this study, we revealed a novel c-FOXP3+ tumor epithelial cell subset marked by diminished E-cadherin and stable FOXP3 expression. These subpopulations not only show robust proliferation and drive angiogenesis via CXCL1, CXCL5, and CXCL8, bypassing VEGFA pathways, but their heightened presence also correlates with adverse PDAC outcomes. By challenging traditional epithelial cell definitions and extending lymphocyte markers to these cells, our findings present innovative targets for PDAC treatment and enrich our understanding of cell biology.

Potential involvement of oncostatinM in the immunosuppressive tumor immune microenvironment in hepatocellular carcinoma with vessels encapsulating tumor clusters.

Vessels encapsulating tumor clusters (VETC) represents an adverse prognostic morphological feature of hepatocellular carcinoma (HCC), which is associated with an immunosuppressive tumor immune microenvironment (TIM). However, the underlying factors characterizing the TIM in HCC with a VETC pattern (VETC-positive HCC) remain uncertain. OncostatinM (OSM), a pleiotropic cytokine of the interleukin-6 family, regulates various biological processes, including inflammation, proliferation, and invasiveness of tumor cells. We aimed to test a hypothesis that OSM is associated with the immunosuppressive TIM of VETC-positive HCC. A total of 397 consecutive HCC patients with curative-intent hepatectomy were included. OSM-positive cells and inflammatory cells including CD4-, CD8-, CD163-, and FOXP3-positive cells were immunohistochemically evaluated. We compared VETC-positive and VETC-negative HCCs in terms of the number of these cells. We found the VETC pattern in 62 patients (15.6%). Our analysis revealed a significant decrease in the expression of arginase-1, a marker associated with mature hepatocyte differentiation, in VETC-positive HCC (p=0.046). The number of tumor-infiltrating OSM-positive cells was significantly low in VETC-positive HCC (p=0.0057). Notably, in VETC-positive HCC, the number of OSM-positive cells was not associated with vascular invasion, whereas in VETC-negative HCC, an increase in the number of OSM-positive cells was associated with vascular invasion (p=0.042). We identified an association between a decrease in OSM-positive cells and the VETC pattern. Additionally, our findings indicate that VETC-positive HCC is characterized by low hepatocyte differentiation and OSM-independent vascular invasion. These findings highlight the potential interaction between VETC-positive HCC cells and their TIM through the reduction of OSM-expressing cells.

FOXP3-positive cell infiltration in the chorionic villi is increased in the placenta accreta and decreased in the placental abruption.

Growing data suggest a role of Treg cells in placentation. The aim of the study was to evaluate Treg cells (FOXP3-positive cells) placental bed infiltration in patients with placenta accrete syndrome (PAS) and patients who experienced placental abruption. The study group included 13 patients with PAS and the control group consisted of 66 women who had caesarean (CD) delivery of whom, 44 patients with elective caesarean (EC) delivery, and 22 patients with urgent caesarean (UC) delivery due to placental abruption. FOXP3 cell infiltration was assessed by means of immunohistochemistry in placental chorionic villous (CV) and in the decidua (D) and cumulatively in the placental bed (PB). We observed significant difference in the degree of FOXP3-positive cell CV infiltration between studied groups (p = 0.04). FOXP3-positive cells were the most commonly observed in PAS patients, while, they were the least frequently presented in patients after UC. The immunoreactivity for FOXP3-positive cells in CV were as follows: PAS 5 (38%), urgent CS 1 (5%) and elective CS 8 (18%) subjects. We found no difference in the presence of FOXP3-positive cells in the D (p = 0.35) and in the PB (p = 0.23) of analyzed groups. FOXP3-cell infiltration was not related with patient age, BMI, gestational age and neonatal birth weight. Our study provides further evidence that abnormal invasive placentation is an associated disturbance of the maternal immune response. Accordingly, we have theorized that alteration of the FOXP3-positive Treg cell infiltration into the placental bed allows trophoblast cell invasion.

Study of immunophenotypic characteristics, clinicopathological parameters and prognosis in gastric cancer microenvironment

Objective: To explore the immunophenotypic characteristics of gastric cancer microenvironment and analyze its correlation with clinicopathological parameters and prognosis of patients. Methods: The expression levels of leukocyte differentiation antigen (CD) 8, CD4, T lymphocyte immunoglobulin mucoprotein 3 (TIM3), human forkhead box protein P3 (Foxp3) and co-localized tumor infiltrating lymphocytes (TILs) were detected in 92 cases of gastric cancer tissue [58 males and 34 females; aged M(Q1, Q3), 70(59, 77) years ] and 84 cases of paracancer tissue [57 males and 27 females, aged 70(59, 77) years] purchased from Shanghai Xinchao Biotechnology Co., Ltd., and the samples were from 28 hospitals in the sample bank. Gastric cancer and adjacent tissues were divided into high expression group and low expression group according to the optimal cut-off value of positive lymphocytepercentage. The expression of immunophenotypes in gastric cancer and adjacent tissues was analyzed. Kaplan-Meier method was used for survival analysis. Cox proportional hazard model was used to explore the prognostic factors of gastric cancer patients. Results: The optimal cut-off values of CD8, CD4, TIM3 and Foxp3 positive cells in gastric cancer were 12.73%, 1.39%, 10.77% and 2.44%, respectively. The expression of Foxp3 in gastric cancer tissues was higher than that in paracancer tissues [M (Q1, Q3), 0.93 (0.45, 2.16) vs 0.31 (0.09, 0.86), P<0.001], and the expression of CD8 [4.92 (2.34, 8.80) vs 8.81 (6.61, 12.17), P<0.001], CD4 [4.79 (1.77, 11.36) vs 8.40 (4.84, 12.77), P=0.022] and TIM3 [5.68 (2.05, 11.58) vs 7.07 (3.13, 11.43), P=0.338] were lower than that in paracancer tissues. There were significant differences in TIM3 expression in gastric cancer patients with different lymph node metastasis and clinical stage (all P<0.05). The 5-year survival rate of patients with high CD4 expression, low TIM3 expression and low Foxp3 expression in gastric cancer tissues was poor, among which the high CD4 expression and low CD4 expression groups were 29.3% and 64.7%, respectively; The high and low TIM3 expression groups were 60.9% and 30.4%, respectively; The high and low Foxp3 expression groups were 64.3% and 33.3%, respectively (all P<0.05). The optimal cut-off values of CD8+TIM3+TILs, CD4+TIM3+TILs, CD8+Foxp3+TILs and CD4+Foxp3+TILs were 3.86%, 0.23%, 0.08% and 0.76%, respectively. Colocalization analysis showed that the expression of CD8+Foxp3+TILs in gastric cancer tissues was higher than that in adjacent tissues(all P<0.05). Multivariate Cox regression analysis showed that high expression of CD4 (HR=3.079, 95%CI: 1.350-7.024,P=0.008), low expression of TIM3 (HR=0.428, 95%CI: 0.208-0.879, P=0.021) and low expression of Foxp3 (HR=0.288, 95%CI: 0.121-0.687, P=0.005) were the influencing factor for the 5-year survival rate of patients with gastric cancer after operation. Conclusions: Gastric cancer tissues have complex immune microenvironment characteristics. The expression of CD4, TIM3 and Foxp3 is closely related to the prognosis of patients.

The High-Risk Human Papillomavirus Type Influences the Tissue Microenvironment in Cervical Intraepithelial Neoplasia Grade 2.

High-risk, cancer-causing human papillomavirus (HPV) types are associated with cervical precancer and cancer. A high proportion of high-risk HPV precancer lesions undergo immune-mediated regression. The purpose of this study was to determine if the tissue microenvironment of HPV16 and 18 (HPV16/18) cervical intraepithelial neoplasia grade 2 lesions differed from other high-risk types (HPV 'other'). Consistent with other studies, we found that progression to higher-grade disease was more frequent in HPV16/18 lesions when compared with HPV 'other' lesions. HPV16/18 lesions were significantly more likely to be indoleamine 2,3,-dioxygenase 1 (IDO1)-positive and were associated with reduced CD8 and FoxP3 T cells in the lesion. In the stroma, reduced Tbet- and CD32-positive cells and increased Blimp1-positive cells were significantly associated with HPV16/18 lesions when compared with HPV 'other' types. On analysis of the IDO1-positive tissues, lesional IDO1 was associated with significantly decreased numbers of CD4-, CD8-, and FoxP3-positive cells in the stroma compared with IDO1-negative tissues. These data suggest that IDO1 expression may impair infiltration of CD4, CD8, and FoxP3 cells into the stroma beneath the precancer lesion. Increased expression of IDO1 may contribute to immune avoidance and an increased frequency of disease progression in HPV16- and 18-positive lesions.

PD-L1-expressing cancer-associated fibroblasts induce tumor immunosuppression and contribute to poor clinical outcome in esophageal cancer

The programmed cell death 1 protein (PD-1)/programmed cell death ligand 1 (PD-L1) axis plays a crucial role in tumor immunosuppression, while the cancer-associated fibroblasts (CAFs) have various tumor-promoting functions. To determine the advantage of immunotherapy, the relationship between the cancer cells and the CAFs was evaluated in terms of the PD-1/PD-L1 axis. Overall, 140 cases of esophageal cancer underwent an immunohistochemical analysis of the PD-L1 expression and its association with the expression of the α smooth muscle actin, fibroblast activation protein, CD8, and forkhead box P3 (FoxP3) positive cells. The relationship between the cancer cells and the CAFs was evaluated in vitro, and the effect of the anti-PD-L1 antibody was evaluated using a syngeneic mouse model. A survival analysis showed that the PD-L1+ CAF group had worse survival than the PD-L1- group. In vitro and in vivo, direct interaction between the cancer cells and the CAFs showed a mutually upregulated PD-L1 expression. In vivo, the anti-PD-L1 antibody increased the number of dead CAFs and cancer cells, resulting in increased CD8+ T cells and decreased FoxP3+ regulatory T cells. We demonstrated that the PD-L1-expressing CAFs lead to poor outcomes in patients with esophageal cancer. The cancer cells and the CAFs mutually enhanced the PD-L1 expression and induced tumor immunosuppression. Therefore, the PD-L1-expressing CAFs may be good targets for cancer therapy, inhibiting tumor progression and improving host tumor immunity.

Eicosapentaenoic acid reduces the proportion of IL-17A–producing T cells in a 3D psoriatic skin model

Psoriasis is a skin disease presenting as erythematous lesions with accentuated proliferation of epidermal keratinocytes, infiltration of leukocytes, and dysregulated lipid metabolism. T cells play essential roles in the disease. n-3 polyunsaturated fatty acids are anti-inflammatory metabolites, which exert an immunosuppressive effect on healthy T cells. However, the precise mechanistic processes of n-3 polyunsaturated fatty acids on T cells in psoriasis are still unrevealed. In this study, we aimed to evaluate the action of eicosapentaenoic acid (EPA) on T cells in a psoriatic skin model produced with T cells. A coculture of psoriatic keratinocytes and polarized T cells was prepared using culture media, which was either supplemented with 10 μM EPA or left unsupplemented. Healthy and psoriatic skin substitutes were produced according to the self-assembly method. In the coculture model, EPA reduced the proportion of IL-17A–positive cells, while increasing that of FOXP3-positive cells, suggesting an increase in the polarization of regulatory T cells. In the 3D psoriatic skin model, EPA normalized the proliferation of psoriatic keratinocytes and diminished the levels of IL-17A. The expression of the proteins of the signal transducer and activator of transcription was influenced following EPA supplementation with downregulation of the phosphorylation levels of signal transducer and activator of transcription 3 in the dermis. Finally, the NFκB signaling pathway was modified in the EPA-supplemented substitutes with an increase in Fas amounts. Ultimately, our results suggest that in this psoriatic model, EPA exerts its anti-inflammatory action by decreasing the proportion of IL-17A–producing T cells.

Clinical and biological activity of FLX475, an oral CCR4 antagonist, in advanced cancer.

2625 Background: FLX475 is a potent and selective CCR4 antagonist, designed to block the recruitment of immunosuppressive regulatory T cells (Treg) into tumors without affecting healthy tissues. Blocking migration of Treg into the tumor microenvironment (TME) has the potential to restore antitumor immunity and synergize with a variety of conventional and immunotherapy-based approaches to overcome immune resistance and broaden clinical efficacy. In a recent interim clinical update from the ongoing FLX475-02 Phase 1/2 trial, evidence of monotherapy and combination activity were reported. FLX475 monotherapy induced complete responses in two of the six evaluable subjects enrolled with EBV+ NK/T cell lymphoma. In checkpoint inhibitor naïve non-small-cell lung cancer (NSCLC), 4/13 subjects (31%) had confirmed partial responses (PRs) following treatment with the combination of FLX475 and pembrolizumab. In this analysis we present biomarker data from patients with broad range of tumor types treated with FLX475 monotherapy. We provide evidence to substantiate the mechanism of action and support the combination of FLX475 with pembrolizumab. Methods: Flow cytometry was used to measure relative proportions of Treg in the periphery. CD8 and FOXP3 positive cells in tumor biopsies were quantified by immunohistochemistry (IHC).Gene set enrichment analysis and immune deconvolution methods were used to interrogate RNAseq data derived from tumor biopsies. Results: FLX475 monotherapy results in a small but significant increase in proportion of circulating CD25+CD127-/low CD4+ Treg by day 8 of treatment. IHC analysis revealed a trend towards increased CD8:FOXP3 ratio in the TME of patient biopsies. Transcriptomic profiles from tumor biopsies of FLX475 monotherapy treated patients exhibited significant changes in immune pathways likely to benefit the antitumor response. Using global gene expression analyses we identified that FLX475 monotherapy altered the transcriptome of tumors to resemble those from patients with favorable clinical outcome to anti-PD(L)-1 treatment. Consistent with the proposed mechanism of action, immune deconvolution identified that FLX475-treated patients experienced a decrease in Treg cell populations. Conclusions: FLX475 monotherapy results in beneficial changes in the TME consistent with our proposed mechanism of action. FLX475 monotherapy is modifying the tumor microenvironment toward a phenotype associated with response to anti-PD-1/anti-PD-L1. Clinical trial information: NCT03674567 .

A DMBA-induced ovarian cancer model: Could it be clinically useful to test OncoTherad and erythropoietin as anticancer approaches?

e17589 Background: The term ovarian carcinoma (OC) refers to a heterogeneous collection of five distinct diseases known as histotypes. While histotype-specific treatment is still a clinical challenge, well-characterized models are required for testing new therapies. OncoTherad is a nanoimmunotherapy developed by University of Campinas/Brazil, which exhibits antitumor properties. Erythropoietin (EPO) has cytoprotective effects including in the ovaries. We assessed whether a chemically-induced animal OC model was representative of human disease by evaluating which histotype it best represents. We evaluated both mutational and immunohistochemical (IHC) biomarkers routinely used for human OC and used the observed features to provide context in the evaluation of OncoTherad and EPO effects. Methods: Thirty-five Fischer rats were distributed into 5 groups: Control (Sham surgery); Cancer (7,12-dimethylbenzoanthracene – DMBA injection in the ovarian bursa, 1.25 mg/kg); OncoTherad (20mg/kg IP); EPO (8.4 µg/kg IP); and OncoTherad+EPO (same doses). Ovary specimens were formalin-fixed into paraffin-embedded donor blocks. After DNA extraction and tissue microarray construction, we assessed typical gene mutations directly by Sanger sequencing (Pik3ca, Ctnnb1, and Kras) or indirectly using IHC surrogates (Arid1a and p53). Finally, we examined biomarkers typical of different OC histotypes (Wt1, Pr, Hnf1β) as well as lymphocyte density (CD3) by IHC. Results: The results were consistent across the cancer-induced animals. The majority of abnormal epithelial cells were Wt1+, Pr-, and Hnf1b-. Therefore, our rat model of DMBA-induced ovarian cancer was most likely serous type ovarian carcinoma, in agreement with the histopathological analysis. The ovarian lesions were molecularly similar to low-grade serous ovarian carcinoma as abnormal pattern of p53 staining was rarely observed. Loss of immunoreactivity for Arid1a protein was seen in some abnormal epithelium. However, the interpretability of mutation surrogates in rat tissues may not always be consistent with IHC analysis systems applied for human tissues. Furthermore, DNA sequencing did not reveal driver mutations in any of the sampled specimens. The treatments, especially OncoTherad+EPO, increased the number of CD3 positive immune cells. After EPO treatment, the tumor and abnormal areas showed a higher number of CD3+ lymphocytes than the normal regions; following a previous work, this could be due to substantial presence of Foxp3 positive cells. Conclusions: The features analyzed favored a low-grade serous carcinoma model in which treatments with OncoTherad and EPO showed immunomodulatory properties related to the reduction of ovarian lesions seen in previous work. The overall data highlight the importance of further characterizations of animal models to provide a complete and specific panel for testing new drugs.

High density and proximity of CD8+ T cells to tumor cells are correlated with better response to nivolumab treatment in metastatic pleural mesothelioma.

The efficacy of immune checkpoint inhibitors (ICIs) in pleural mesothelioma has recently been established. The response to ICIs can be predicted by quantitative analysis of cells and their spatial distribution in the tumor microenvironment (TME). However, the detailed composition of the TME in pleural mesothelioma has not been reported. We evaluated the association between the TME and response to ICIs in this cancer. A retrospective analysis of 22 pleural mesothelioma patients treated with nivolumab in different centers was performed using surgical specimens. Four patients had a partial response to nivolumab (response group) and 18 patients had stable or progressive disease (nonresponse group). The number of CD4, CD8, FoxP3, CK, and PD-L1 positive cells, cell density, and cell-to-cell distance were analyzed by multiplex immunofluorescence. PD-L1 expression did not differ significantly between the response and nonresponse groups. The density of total T cells and of CD8+ T cells was significantly higher in the response than in the nonresponse group. CD8+ T cells were more clustered and located closer to tumor cells, whereas regulatory T cells were located further from tumor cells in the response than in the nonresponse group. High density and spatial proximity of CD8+ T cells to tumor cells were associated with better response to nivolumab, whereas the proximity of regulatory T cells to tumor cells was associated with worse response, suggesting that the distinct landscape of the TME could be a potential predictor of ICI efficacy in pleural mesothelioma.

Abstract LB195: Immunotherapies that repolarize macrophages and CD4 T cells enhance the effect of chemotherapy in high-grade serous ovarian cancer

Abstract We asked if single-cell RNA sequencing (scRNA-seq) analysis of tumor immune cells in high-grade serous ovarian cancer (HGSOC) would reveal ways to enhance effects of neo-adjuvant chemotherapy (NACT). Analysis of 64,097 immune cells from seven HGSOC omental metastases showed that positive effects of NACT on immune responses were counterbalanced by induction of immunosuppressive mechanisms, especially related to antigen presentation and Treg activity. We identified stabilin-1 (Clever-1) on macrophages and FOXP3 in Tregs as targets and validated actions of their inhibitors in vitro. ScRNA-seq analysis of 69,781 cells from chemotherapy-treated syngeneic mouse HGSOC tumors showed significant agreement with the patient results. Combinations of chemotherapy with anti-stabilin1 antibody and/or FOXP3 inhibitor (AZD8701), FOXP3i, significantly increased median survival of mice with established peritoneal disease. Long-term survivors (300 days+) were resistant to tumor rechallenge. Analysis of bulk RNA sequencing data from treated murine tumors confirmed our hypothesis and suggested potential mechanisms to explain the anti-tumor response seen in the murine models. Tumors treated with chemotherapy plus anti-stabilin1 antibody showed significant enrichment of anti-tumor macrophage signature and antigen presentation pathway compared to chemotherapy alone. Tumors treated with chemotherapy plus FOXP3i in combination with anti-stabilin1 antibody showed significant upregulation of antigen presentation, T cell activation and cytotoxicity and T helper 1 differentiation pathways. There was significant reduction in FOXP3 positive cells and significant increase of Tbet positive cells in FOXP3i treated murine tumors suggesting repolarization of naive T cells in the tumor microenvironment towards a more anti-tumor T helper phenotype. As there are early phase clinical trials of FOXP3 inhibitor and anti-stabilin1 (Clever-1) antibody in patients with advanced cancer, these results suggest ways of improving response to chemotherapy not only in HGSOC but in other cancers that are treated by NACT. Citation Format: Samar Elorbany, Chiara Berlato, Larissa Carnevalli, Eleni Maniati, Jun Wang, Simon Barry, Ranjit Manchanda, Julia Kzhyshkowska, Frances Balkwill. Immunotherapies that repolarize macrophages and CD4 T cells enhance the effect of chemotherapy in high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB195.

Disruption of IDO signaling pathway alleviates chronic unpredictable mild stress-induced depression-like behaviors and tumor progression in mice with breast cancer.

Women with breast cancer (BC) are often combined with psychological disorder such as depression and anxiety. Depression is associated or correlated with increased toxicity and severity of physical symptoms. However, the mechanism of BC progression related to the regulation of emotion-related circuitry remains to be further explored. The study aims to investigate indoleamine 2,3-dioxygenase (IDO) pathway mechanism underlying stress-induced progression of BC. BC cell line 4T1 was subcutaneously inoculated into BALB/c mice, and they then received daily chronic unpredictable mild stressors (CUMS) for 12weeks. Depression-like behavior tests were conducted, including sucrose preference test (SPT), tail suspension test (TST), forced swimming test (FST), and novelty suppressed feeding test (NSF). The levels of 5-Hydroxytryptamine (5-HT) and inflammatory factors, IL-6, CXCL1, IL-10 and IL-4 were measured by enzyme linked immunosorbent assay (ELISA) of mouse serum. Immunohistochemical staining was performed to detect Ki67- or FOXP3-positive tumor cells. The status of IDO signaling pathway was assessed by immunoblotting analysis. CUMS induced depression-like behaviors, decreased the level of 5-HT, promoted tumor progression, enhanced the immunohistochemical staining of Ki-67, and promoted the activation of IDO signaling pathway in BC mice. The IDO signaling pathway was disrupted in mice by lentiviral transduction of shRAN-IDO. Lentivirus-mediated IDO knockdown attenuated CUMS-induced depression-like behaviors, increased the level of 5-HT, inhibited tumor progression, and reduced the immunohistochemical staining of Ki-67 in BC mice. The present study suggests that disruption of IDO signaling pathway alleviates CUMS-induced depression-like behaviors and inhibits tumor progression in BC mice.

Programmed death-ligand 1 expression in the immune compartment of colon carcinoma

AbstractProgrammed cell death ligand 1 (PD-L1) on tumor cells is a significant prognostic biomarker for a number of malignancies, although less is known about the significance of PD-L1 positive immune cells in colon carcinoma. The purpose of this study is to evaluate the role of PD-L1 in a large cohort of colon carcinomas to identify patterns of PD-L1 expression in the tumor microenvironment and its correlation with other key immune subsets to better understand the impact of these immune cells. We assessed 1218 colon carcinomas on representative tissue microarray sections, gathered relevant clinicopathologic information, and performed immunohistochemical staining for mismatch repair proteins, CD8, CD163, LAG3, PD-L1, FoxP3, and BRAF V600E. We then performed automated quantification; manual quantification was used for PD-L1 tumor cells and immune cells. Dual PD-L1/PU.1 immunostain was also performed. The majority of PD-L1 positive cells expressed PU.1 thus representing tumor-associated macrophages. Based on the median number of PD-L1 positive immune cells (7.6/mm2), we classified tumors into two classes: (1) PD-L1 immune cell low and (2) PD-L1 immune cell high. PD-L1 immune cell high colon carcinomas showed favorable prognostic pathologic features including less frequent extramural venous invasion (p = 0.0001) and lower AJCC stage (p = 0.0001); they were also more commonly associated with deficient mismatch repair (dMMR) (p = 0.0001) and BRAF V600E reactivity. PD-LI immune cell high tumors were associated with high CD8, CD163, and FoxP3 positive cells (p = 0.0001, respectively). PD-L1 immune cell high and LAG3 high colon carcinomas were associated with improved disease-specific survival (p = 0.0001 and 0.001, respectively). PD-L1 expression on tumor cells was not associated with disease-specific survival. On multivariate analysis of chemotherapy naïve stage 2 colon carcinomas, only extramural venous invasion (p = 0.002), perineural invasion (p = 0.001) and PD-L1 immune cell expression (p = 0.032) correlated with disease-specific survival. Resected colonic carcinomas with high expression of PD-L1 and LAG3 proteins on immune cells were associated with improved prognosis in colon carcinoma. The mechanism underlying the improved prognosis of colon carcinomas bearing high numbers of immunoregulatory cells needs further investigation.

Herpesvirus entry mediator regulates the transduction of Tregs via STAT5/Foxp3 signaling pathway in ovarian cancer cells.

The ratio of regulatory T cells (Treg) in peripheral blood of cancer patients has a closely correlation to the occurrence and development of ovarian cancer. In this study, our aim to explore the expression of herpesvirus entry mediator (HVEM) in ovarian cancer and its correlation with Tregs. The expression of HVEM in peripheral blood of ovarian cancer patients was detected by ELISA, and the ratio of CD4+ CD25 + Foxp3 positive Tregs cells was detected by flow cytometry. Ovarian cancer cell lines with high- and low-HVEM expression were constructed. CD4+ cells were co-cultured with ovarian cancer (OC) cells, and the expressions of IL-2 and TGF-β1 in the supernatant of cells were detected by ELISA, and western blot was used to detect the expressions of STAT5, p-STAT5, and Foxp3. The results indicated that the number of Treg cells in the peripheral blood of OC patients increased, and the expression of HVEM increased, the two have a certain correlation. At the same time, the overexpression of HVEM promoted the expression of cytokines IL-2 and TGF- β1, promoted the activation of STAT5 and the expression of Foxp3, leading to an increase in the positive rate of Treg, while the HVEM gene silence group was just the opposite. Our results showed that the expression of HVEM in OC cells has a positive regulation effect on Tregs through the STAT5/Foxp3 signaling pathway. To provide experimental basis and related mechanism for the clinical treatment of ovarian cancer.