FoxP3 is a key transcription factor for the development and function of natural CD4(+) regulatory T cells (Treg cells). Here we show that human FoxP3(+)CD4(+) T cells were composed of three phenotypically and functionally distinct subpopulations: CD45RA(+)FoxP3(lo) resting Treg cells (rTreg cells) and CD45RA(-)FoxP3(hi) activated Treg cells (aTreg cells), both of which were suppressive in vitro, and cytokine-secreting CD45RA(-)FoxP3(lo) nonsuppressive T cells. The proportion of the three subpopulations differed between cord blood, aged individuals, and patients with immunological diseases. Terminally differentiated aTreg cells rapidly died whereas rTreg cells proliferated and converted into aTreg cells in vitro and in vivo. This was shown by the transfer of rTreg cells into NOD-scid-common gamma-chain-deficient mice and by TCR sequence-based T cell clonotype tracing in peripheral blood in a normal individual. Taken together, the dissection of FoxP3(+) cells into subsets enables one to analyze Treg cell differentiation dynamics and interactions in normal and disease states, and to control immune responses through manipulating particular FoxP3(+) subpopulations.

Background:PD-L1 (programmed cell death 1 ligand 1) on tumour cells suppresses host immunity through binding to its receptor PD-1 on lymphocytes, and promotes peritoneal dissemination in mouse models of ovarian cancer. However, how PD-L1 expression is regulated in ovarian cancer microenvironment remains unclear.Methods:The number of CD8-positive lymphocytes and PD-L1 expression in tumour cells was assessed in ovarian cancer clinical samples. PD-L1 expression and tumour progression in mouse models under conditions of altering IFN-γ signals was assessed.Results:The number of CD8-positive cells in cancer stroma was very high in peritoneally disseminated tumours, and was strongly correlated to PD-L1 expression on the tumour cells (P<0.001). In mouse models, depleting IFNGR1 (interferon-γ receptor 1) resulted in lower level of PD-L1 expression in tumour cells, increased the number of tumour-infiltrating CD8-positive lymphocytes, inhibition of peritoneal disseminated tumour growth and longer survival (P=0.02). The injection of IFN-γ into subcutaneous tumours induced PD-L1 expression and promoted tumour growth, and PD-L1 depletion completely abrogated tumour growth caused by IFN-γ injection (P=0.01).Conclusions:Interferon-γ secreted by CD8-positive lymphocytes upregulates PD-L1 on ovarian cancer cells and promotes tumour growth. The lymphocyte infiltration and the IFN-γ status may be the key to effective anti-PD-1 or anti-PD-L1 therapy in ovarian cancer.

VEGF expression in ovarian cancer induced MDSCs, inhibited local immunity, and contributed to poor prognosis. Clin Cancer Res; 23(2); 587-99. ©2016 AACR.

Purpose: Ovarian cancer often progresses by disseminating to the peritoneal cavity, but how the tumor cells evade host immunity during this process is poorly understood. Programmed cell death 1 ligand 1 (PD-L1) is known to suppress immune system and to be expressed in cancer cells. The purpose of this study is to elucidate the function of PD-L1 in peritoneal dissemination.Experimental Design: Ovarian cancer cases were studied by microarray and immunohistochemistry. PD-L1 expression in mouse ovarian cancer cell line in various conditions was assessed by flow cytometry. PD-L1-overexpression cell line and PD-L1-depleted cell line were generated, and cytolysis by CTLs was analyzed, and alterations in CTLs were studied by means of timelapse and microarray. These cell lines were injected intraperitoneally to syngeneic immunocompetent mice.Results: Microarray and immunohistochemistry in human ovarian cancer revealed significant correlation between PD-L1 expression and peritoneal positive cytology. PD-L1 expression in mouse ovarian cancer cells was induced upon encountering lymphocytes in the course of peritoneal spread in vivo and coculture with lymphocytes in vitro. Tumor cell lysis by CTLs was attenuated when PD-L1 was overexpressed and promoted when it was silenced. PD-L1 overexpression inhibited gathering and degranulation of CTLs. Gene expression profile of CTLs caused by PD-L1-overexpressing ovarian cancer was associated with CTLs exhaustion. In mouse models, PD-L1 depletion resulted in inhibited tumor growth in the peritoneal cavity and prolonged survival.Conclusion: PD-L1 expression in tumor cell promotes peritoneal dissemination by repressing CTL function. PD-L1-targeted therapy is a promising strategy for preventing and treating peritoneal dissemination.

GAS showed aggressive behavior with ominous histopathological predictors as well as decreased survival.• GAS also showed resistance to radiotherapy.• GAS is therefore considered a distinct entity that should be distinguished from UEA. a b s t r a c tObjective. Gastric-type mucinous carcinoma (GAS) is a novel variant of mucinous carcinoma of the uterine cervix. As shown in the original Japanese group description, in recent studies, GAS represents a more aggressive disease than the usual-type endocervical adenocarcinoma (UEA). Detailed clinicopathological features of this variant remain to be elucidated in a larger series of patients.Methods. Patients were enrolled by the Gynecologic Cancer Study Group of the Japan Clinical Oncology Group after receiving the approval of each Institutional Review Board. The study population comprised of women with stage I to II endocervical adenocarcinomas who underwent surgery between 2000 and 2009. Representative slides were evaluated by central pathological review (CPR), categorized into either GAS or UEA, and correlated with clinicopathological features and outcome.Results. Among the 393 enrolled patients with endocervical adenocarcinoma, 328 patients met the criteria for CPR and the study eligibility criteria and were included in further analysis. A total of 95 of the 328 tumors were classified as GAS. Compared with UEA, GAS was more significantly associated with bulky mass, deep stromal invasion, lymphovascular space invasion, parametrial invasion, ovarian metastasis, positive ascitic fluid cytology, j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / y g y n o pelvic lymph node metastasis, and pathological (p) T stage but was not related to the degree of histological differentiation. Disease-free survival (P b 0.0001) and overall survival (P b 0.0001) were poorer in patients with GAS than in those with UEA.Conclusions. GAS showed aggressive behavior with ominous histopathological predictors as well as decreased survival. GAS is therefore considered a distinct entity that should be distinguished from UEA.Clinical trial information. UMIN Clinical Trials Registry: UMIN000007987

Recently, The Cancer Genome Atlas data revealed four molecular subtypes of high-grade serous ovarian carcinoma (HGSOC) exhibiting distinct prognoses. We developed four novel HGSOC histopathological subtypes by focusing on tumor microenvironment: mesenchymal transition, defined by a remarkable desmoplastic reaction; immune reactive by lymphocytes infiltrating the tumor; solid and proliferative by a solid growth pattern; and papilloglandular by a papillary architecture. Unsupervised hierarchical clustering revealed four clusters correlated with histopathological subtypes in both Kyoto and Niigata HGSOC transcriptome data sets (P < 0.001). Gene set enrichment analysis revealed pathways enriched in our histopathological classification significantly overlapped with the four molecular subtypes: mesenchymal, immunoreactive, proliferative, and differentiated (P < 0.0001, respectively). In 132 HGSOC cases, progression-free survival and overall survival were best in the immune reactive, whereas overall survival was worst in the mesenchymal transition (P < 0.001, respectively), findings reproduced in 89 validation cases (P < 0.05, respectively). The CLOVAR_MES_UP single-sample gene set enrichment analysis scores representing the mesenchymal molecular subtype were higher in paclitaxel responders than nonresponders (P = 0.002) in the GSE15622 data set. Taxane-containing regimens improved survival of cases with high MES_UP scores compared with nontaxane regimens (P < 0.001) in the GSE9891 data set. Our novel histopathological classification of HGSOC correlates with distinct prognostic transcriptome subtypes. The mesenchymal transition subtype might be particularly sensitive to taxane.

The aim of this study was to evaluate the local immune status of human ovarian cancers by the comprehensive analysis of tumor-infiltrating immune cells and immunosuppressive factors, and to elucidate the local immunity in clinical course. The numbers of CD1α+, CD4+, CD8+, CD57+, forkhead box P3+ and programmed cell death-1+ cells were counted, and the intensity of immunosuppressive factors, such as programmed cell death-1 ligand (PD-L)1, PD-L2, cyclooxygenase (COX)-1, COX-2 and transforming growth factor β1, were evaluated in 70 ovarian cancer specimens stained by immunohistochemistry. Then hierarchical clustering of these parameters showed the four clusters into ovarian cancer cases. Cluster 1, which had significantly better prognosis than the others, was characterized by high infiltration of CD4+ and CD8+ cells. In conclusion the comprehensive analysis of local immune status led to subdivide ovarian cancers into groups with better or worse prognoses and may guide precise understanding of the local immunity.

Recent studies of the interferon-induced transcription factor STAT1 have associated its dysregulation with poor prognosis in some cancers, but its mechanistic contributions are not well defined. In this study, we report that the STAT1 pathway is constitutively upregulated in type II endometrial cancers. STAT1 pathway alteration was especially prominent in serous papillary endometrial cancers (SPEC) that are refractive to therapy. Our results defined a "SPEC signature" as a molecular definition of its malignant features and poor prognosis. Specifically, we found that STAT1 regulated MYC as well as ICAM1, PD-L1, and SMAD7, as well as the capacity for proliferation, adhesion, migration, invasion, and in vivo tumorigenecity in cells with a high SPEC signature. Together, our results define STAT1 as a driver oncogene in SPEC that modulates disease progression. We propose that STAT1 functions as a prosurvival gene in SPEC, in a manner important to tumor progression, and that STAT1 may be a novel target for molecular therapy in this disease. Cancer Res; 74(22); 6519-30. Ó2014 AACR.