Yumiko Yoshioka

Functional Delineation and Differentiation Dynamics of Human CD4+ T Cells Expressing the FoxP3 Transcription Factor

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.

IFN-γ from lymphocytes induces PD-L1 expression and promotes progression of ovarian cancer

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.

PD-L1 on Tumor Cells Is Induced in Ascites and Promotes Peritoneal Dissemination of Ovarian Cancer through CTL Dysfunction

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. Clin Cancer Res; 19(6); 1363–74. ©2012 AACR.

The comprehensive assessment of local immune status of ovarian cancer by the clustering of multiple immune factors

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.

Differential effects of inhibition of bone morphogenic protein (BMP) signalling on T-cell activation and differentiation.

Bone morphogenetic proteins (BMPs) are involved in patterning and cellular fate in various organs including the thymus. However, the redundancy of BMPs and their receptors have made it difficult to analyse their physiological roles. Here, we investigated the role of BMP signalling in peripheral CD4+ T cells by analysing the effects of an inhibitor of BMP signalling, dorsomorphin. Dorsomorphin suppressed phosphorylation of SMAD1/5/8, suggesting that BMP signalling naturally occurs in T cells. At high doses, dorsomorphin suppressed proliferation of T cells in a dose‐dependent manner, inducing G1 arrest. Also, dorsomorphin suppressed Th17 and induced Treg‐cell differentiation, while preserving Th2 differentiation. Dorsomorphin efficiently suppressed IL‐2 production even at low doses in mouse CD4+ T cells, suggesting that the BMP‐Smad signalling physiologically regulates IL‐2 transcription in these cells. In addition, recombinant BMP2 induced a dose‐dependent multiphasic pattern of IL‐2 production, while Noggin suppressed IL‐2 production at higher doses in Jurkat cells. Notably, BMP signalling controlled the phosphorylation of RUNX1, revealing the molecular nature of its effect. Collectively, we describe multiple effects of dorsomorphin and Noggin on T‐cell activation and differentiation, demonstrating a physiological role for BMP signalling in these processes.

GPR54 Is a Target for Suppression of Metastasis in Endometrial Cancer

Invasion into deep myometrium and/or lymphovascular space is a well-known risk factor for endometrial cancer metastasis, resulting in poor prognosis. It is therefore clinically important to identify novel molecules that suppress tumor invasion. Reduced expression of the metastasis suppressor, kisspeptin (KISS1), and its endogenous receptor, GPR54, has been reported in several cancers, but the significance of the KISS1/GPR54 axis in endometrial cancer metastasis has not been clarified. Metastin-10 is the minimal bioactive sequence of genetic products of KISS1. Clinicopathological analysis of 92 endometrial cancers revealed overall survival is improved in cancers with high expression of GPR54 (P < 0.05) and that GPR54 expression is associated with known prognostic factors including FIGO stage, grade, and deep myometrial invasion. Through RNAi and microarray analyses, metastin-10 was predicted to suppress metastasis of GPR54-expressing endometrial cancers in vivo. Methylation analysis revealed GPR54 is epigenetically regulated. Metastin-GPR54 axis function was restored following treatment with the DNA hypomethylating agent 5-aza-DC. These data suggest that metastin-10 may be effective at inhibiting the metastatic spread of endometrial cancers in combination with demethylating agents to induce GPR54 expression. Mol Cancer Ther; 10(4); 580–90. ©2011 AACR.

Expression of Vascular Endothelial Growth Factor in Ovarian Cancer Inhibits Tumor Immunity through the Accumulation of Myeloid-Derived Suppressor Cells.

Purpose: High VEGF expression in ovarian cancer is an unfavorable prognostic factor. However, the role of VEGF in tumor immunity remains unclear. Here, we examined the impact of VEGF on local immunity, including induction of myeloid-derived suppressor cells (MDSC), in ovarian cancer. Experimental Design: High-grade serous ovarian cancer (HGSOC) cases were analyzed by gene expression microarray and IHC for VEGF, CD8, and CD33. VEGF receptor (VEGFR) 1 and VEGFR2 expression levels on MDSCs were analyzed in a mouse model, and the direct effects of VEGF-A on MDSC expansion were investigated. Gr1+ MDSCs and lymphocyte frequencies were analyzed in control tumors and tumors derived from cells harboring short hairpin RNA targeting Vegf-a. In addition, the therapeutic effects of anti-Gr-1 antibodies were examined. Results: Microarray analysis revealed the upregulation of several myeloid cell chemoattractants and the downregulation of lymphocyte-related pathways in cases with high VEGF expression. In immunohistochemical analysis, VEGF expression in peritoneal dissemination correlated with MDSC infiltration. Cases with high MDSC infiltration, which was inversely correlated with intratumoral CD8+ T-cell infiltration, exhibited shorter overall survival. In a mouse model, intratumoral MDSCs expressed both VEGFR1 and VEGFR2. MDSC migration and differentiation were augmented by VEGF signaling. Vegf-a knockdown in tumor cells resulted in decreased MDSC infiltration and increased CD8+ T-cell infiltration. Moreover, treatment with anti-Gr-1 antibodies delayed the growth of control tumors, whereas Vegf-a-knockdown tumors were unaffected by anti-Gr-1 antibody treatment. Conclusions: VEGF expression in ovarian cancer induced MDSCs, inhibited local immunity, and contributed to poor prognosis. Clin Cancer Res; 23(2); 587–99. ©2016 AACR.

The BMP signaling pathway leads to enhanced proliferation in serous ovarian cancer-A potential therapeutic target.

Members of the transforming growth factor‐β (TGF‐β) superfamily transduce signals via SMAD proteins. SMAD2 and SMAD3 mediate TGF‐β signaling, whereas SMAD1, SMAD5, and SMAD8/9 transduce bone morphogenetic protein (BMP) signals. We would like to identify the function of BMP/SMAD5 signaling in serous ovarian cancer. The protein levels of total SMAD5 and phosphorylated SMAD5 (pSMAD5) were examined by immunohistochemical analysis using clinical serous ovarian cancer samples. Following treatment with either recombinant BMP2 (rBMP2) or Dorsomorphin (DM), western blotting was performed to observe pSMAD5 protein in the cytoplasm and the nucleus, separately. Cell proliferation was detected in SMAD5 knockdown serous ovarian cancer cell lines cultured with DM or rBMP2. The impact of DM or rBMP2 on tumor growth was observed in a mouse model of serous ovarian cancer. An inverse correlation was observed between pSMAD5 levels in the nucleus and the prognosis of patients with serous ovarian cancer. The treatment of SK‐OV‐3 with rBMP2 stimulated pSMAD5 translocation from the cytoplasm to the nucleus, and the addition of DM inhibited this effect. The proliferation of ovarian cancer cell lines was enhanced by BMP2 and suppressed by DM via SMAD5 in vitro. In vitro and in vivo experiments clearly demonstrated BMP2‐stimulated proliferation of serous ovarian cancer and inhibition of this effect by DM. Our data suggests that BMP/SMAD5 signaling plays an important role and, therefore, becomes a potential therapeutic target in serous ovarian cancer.

Two cases of recurrent ovarian clear cell carcinoma treated with sorafenib

Sorafenib is an oral multikinase inhibitor targeting Raf and other kinases. The anti-tumor effect of sorafenib is thought to be mediated through its inhibition of the RAS–Raf–Erk pathway, as well as its inhibition of VEGFR and PDGFR. Sorafenib has been effective at treating patients with renal cell carcinoma (RCC). Ovarian clear cell carcinoma (OCCC) is a chemoresistant subtype of ovarian cancer. OCCC is represented by cells with clear cytoplasm that resemble those observed in RCC. Using a microarray database, the gene expression profile of OCCC was similar to that of RCC. The effects of sorafenib against human OCCC are unknown. Therefore, we used sorafenib to treat two patients with recurrent chemoresistant OCCC, and observed good effect in both of them without severe side effects. We believe that sorafenib is an effective agent against OCCC. Given the chemoresistant nature of this tumor, this drug appears to be very valuable.

Prediction of taxane and platinum sensitivity in ovarian cancer based on gene expression profiles.

OBJECTIVE Prognoses of ovarian cancer (OC) have improved with the paclitaxel-carboplatin regimen. However, it remains unclear which cases exhibit a genuine benefit from taxane or from platinum. We aimed to predict taxane and platinum sensitivity in OC via gene expression. METHODS We identified differentially expressed genes in responsive and resistant cases from advanced OC biopsy expression dataset GSE15622, containing responses to paclitaxel or carboplatin monotherapy. These genes generated a scoring system for prediction of drug response by applying single-sample gene set enrichment analysis. Discriminative metrics termed the T-score and C-score were derived. RESULTS High C-score levels were significant in responders compared to non-responders in a separate cisplatin treatment dataset (GSE18864, p=0.043). High C-score groups also had significantly better progression-free survival in three OC datasets (The Cancer Genome Atlas, TCGA: p=0.02; GSE9891: p=0.03; GSE30161: p=0.001). In two additional datasets of advanced OC, high T-scores could associate taxane and platinum regimens with better survival than non-taxane and platinum regimens (GSE9891: p<0.0001; GSE3149: p=0.045), whereas in cases with low T-scores, different chemotherapeutic regimens did not result in a significant difference. Assessing TCGA and GSE9891, T-scores were elevated in the C1/Mesenchymal subtype, whereas C-scores were elevated in the C5/Proliferative subtype and were lower in the C1/Mesenchymal subtype (p<0.0001, respectively). C- and T-scores negatively correlated with each other, suggesting complementary roles of taxane and platinum. CONCLUSIONS Our proposal and finding of a scoring system that could predict platinum or taxane response could be useful to develop individualized treatments to ovarian cancer.