Phenotypic and Functional Changes of Peripheral Ly6C(+) T Regulatory Cells Driven by Conventional Effector T Cells

A relatively high affinity/avidity of T cell receptor (TCR) recognition for self-peptide bound to major histocompatibility complex II (self-pMHC) ligands is a distinctive feature of CD4 T regulatory (Treg) cells, including their development in the thymus and maintenance of their suppressive functions in the periphery. Despite such high self-reactivity, however, all thymic-derived peripheral Treg populations are neither homogenous in their phenotype nor uniformly immune-suppressive in their function under steady state condition. We show here that based on the previously defined heterogeneity in the phenotype of peripheral Treg populations, Ly6C expression on Treg marks a lower degree of activation, proliferation, and differentiation status as well as functional incompetence. We also demonstrate that Ly6C expression on Treg in a steady state is either up-or downregulated depending on relative amounts of tonic TCR signals derived from its contacts with self-ligands. Interestingly, peripheral appearance and maintenance of these Ly6C-expressing Treg cells largely differed in an age-dependent manner, with their proportion being continuously increased from perinatal to young adult period but then being gradually declined with age. The reduction of Ly6C(+) Treg in the aged mice was not due to their augmented cell death but rather resulted from downregulation of Ly6C expression. The Ly6C down-regulation was accompanied by proliferation of Ly6C(+) Treg cells and subsequent change into Ly6C-effector Treg with concomitant restoration of immune-suppressive activity. Importantly, we found that this phenotypic and functional change of Ly6C(+) Treg is largely driven by conventional effector T cell population. Collectively, these findings suggest a potential cross-talk between peripheral Treg subsets and effector T cells and provides better understanding for Treg homeostasis and function on maintaining self-tolerance Copyright © 2018 Lee, Kim, Yi, Kim, Kim, Han, Sprent, Lee, Surh and Cho. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.ⓒ 2007 - 2018 Frontiers Media S.A. All Rights Reserved

Tumorigenicity of EGFR- and/or HER2-Positive Breast Cancers Is Mediated by Recruitment of Tumor-Associated Macrophages

Basal-like breast cancer (BLBC) has a clinically aggressive nature. It is prevalent in young women and is known to often relapse rapidly. To date, the molecular mechanisms regarding the aggressiveness of BLBC have not been fully understood. In the present study, mechanisms of aggressiveness of BLBC involving EGFR and/or HER2 expression and interactions between tumor and tumor-associated macrophages (TAMs) were explored. The prognosis of breast cancer patients who underwent surgery at Samsung Medical Center was analyzed. It was found that the co-expression of EGFR and HER2 was associated with a worse prognosis. Therefore, we generated EGFR-positive BLBC cells with stable HER2 overexpression and analyzed the profile of secretory cytokines. Chemokine (C-C motif) ligand 2 (CCL2) expression was increased in HER2-overexpressed BLBC cells. Recombinant human CCL2 treatment augmented the motility of TAMs. In addition, the conditioned culture media of HER2-overexpressed BLBC cells increased the motility of TAMs. Furthermore, activation of TAMs by CCL2 or the conditioned culture media of HER2-overexpressed cells resulted in the production of pro-inflammatory cytokines, such as IL-8 and IL-1β. These observations reveal that CCL2 derived from EGFR and HER2 co-expressed BLBC cells can lead to increased TAM recruitment and the induction of IL-8 and IL-1β from recruited TAMs, triggering the tumorigenesis of breast cancer with the expression of both EGFR and HER2. Our findings demonstrate that EGFR+ and HER2+ BLBC aggressiveness is partially mediated through the interaction between BLBC and TAMs recruited by CCL2

Berberine Suppresses Cell Motility Through Downregulation of TGF-β1 in Triple Negative Breast Cancer Cells

Background/Aims: Transforming growth factor-beta proteins (TGF-βs) are multifunctional growth factors and powerful modulators of the epithelial-mesenchymal transition (EMT) in a variety of cancer types including breast and lung cancer cells. Here, we demonstrated the inhibitory effect of berberine (BBR) on tumor growth and metastasis of triple negative breast cancer (TNBC) cells via suppression of TGF-β1 expression. Methods: The levels of mRNA expression were analyzed by real-time PCR. The levels of MMP-2, MMP-9 and TGF-β1 protein expression were analyzed by zymography and confocal microscopy, respectively. Cell migration was analyzed by wound healing assay. Tumorigenicity of TNBC cells such as tumor growth and metastasis was analyzed using xenograft models. Results: In a clinical data set, aberrant TGF-β1 expression was associated with poor prognosis of breast cancer patients. Our in vitro results using TNBC cells showed that the expression levels of matrix metalloproteinase (MMP)-2 and MMP-9 and the capacity for cell migration were increased by TGF-β1 treatment. In contrast, basal levels of MMP-2 and MMP-9 were suppressed by a specific TGF-β receptor I inhibitor, SB431542. In addition, TGF-β1–induced MMP-2 and MMP-9 expression and cell migration were decreased by SB431542. Interestingly, we showed for the first time that BBR decreased the level of TGF-β1, but not TGF-β2, in TNBC cells. Furthermore, BBR significantly decreased the level of MMP-2 expression as well as the capacity for cell migration in TNBC cells. Finally, we examined the effect of BBR on in vivo tumor growth and lung metastasis in MDA-MB231 and 4T1 breast cancer xenograft models and showed that both were significantly decreased following BBR treatment. Conclusion: BBR suppresses tumorigenicity of TNBC cells through inhibition of TGF-β1 expression. Therefore, we demonstrate that BBR could be a promising drug for treatment of TNBC

TCB2, a new anti-human interleukin-2 antibody, facilitates heterodimeric IL-2 receptor signaling and improves anti-tumor immunity

IL-2 is a pleiotropic cytokine that plays an essential role in the survival, expansion, and function of CD8 T cells, regulatory T cells (Tregs), and natural killer (NK) cells. Previous studies showed that binding IL-2 with an anti-IL-2 monoclonal antibody (mAb) with a particular specificity could block its interaction with IL-2R alpha, which is mainly expressed on Tregs. This selectivity can enhance the anti-tumor effects of IL-2 by activating CD8 T and NK cells, while disfavoring Treg stimulation. Based on this, we newly developed a series of anti-human IL-2 (hIL-2) mAbs (TCB1-3) that selectively stimulate CD8 T and NK cells without overtly activating Tregs. Among them, the hIL-2/TCB2 complex (hIL-2/TCB2c) exerted the best efficacy by inducing a prodigious expansion of host memory phenotype (MP) CD8 T (60-fold) and NK cells (18-fold) with less efficient Treg proliferation (5-fold). As a result, there was an average eightfold increase in the ratio of MP CD8 to Tregs. Accordingly, hIL-2/TCB2c strongly inhibited the growth of B16F10, MC38, and CT26 tumors. More remarkably, hIL-2/TCB2c showed synergy with checkpoint inhibitors such as anti-CTLA-4 or PD1 antibodies, and resulted in almost complete regression of implanted tumors and resistance to secondary tumor challenge. For direct clinical use, we generated a humanized form of TCB2 that had equal immunostimulatory and anti-tumor efficacy as a murine one. Collectively, these results show that TCB2 can provide a potent immunotherapeutic modality either alone or together with checkpoint inhibitors in cancer patients11Nsciescopu

Phenotypic and Functional Changes of Peripheral Ly6C+ T Regulatory Cells Driven by Conventional Effector T Cells

A relatively high affinity/avidity of T cell receptor (TCR) recognition for self-peptide bound to major histocompatibility complex II (self-pMHC) ligands is a distinctive feature of CD4 T regulatory (Treg) cells, including their development in the thymus and maintenance of their suppressive functions in the periphery. Despite such high self-reactivity, however, all thymic-derived peripheral Treg populations are neither homogenous in their phenotype nor uniformly immune-suppressive in their function under steady state condition. We show here that based on the previously defined heterogeneity in the phenotype of peripheral Treg populations, Ly6C expression on Treg marks a lower degree of activation, proliferation, and differentiation status as well as functional incompetence. We also demonstrate that Ly6C expression on Treg in a steady state is either up- or downregulated depending on relative amounts of tonic TCR signals derived from its contacts with self-ligands. Interestingly, peripheral appearance and maintenance of these Ly6C-expressing Treg cells largely differed in an age-dependent manner, with their proportion being continuously increased from perinatal to young adult period but then being gradually declined with age. The reduction of Ly6C+ Treg in the aged mice was not due to their augmented cell death but rather resulted from downregulation of Ly6C expression. The Ly6C downregulation was accompanied by proliferation of Ly6C+ Treg cells and subsequent change into Ly6C− effector Treg with concomitant restoration of immune-suppressive activity. Importantly, we found that this phenotypic and functional change of Ly6C+ Treg is largely driven by conventional effector T cell population. Collectively, these findings suggest a potential cross-talk between peripheral Treg subsets and effector T cells and provides better understanding for Treg homeostasis and function on maintaining self-tolerance

Phenotypic and Functional Changes of Peripheral Ly6C+ T Regulatory Cells Driven by Conventional Effector T Cells

A relatively high affinity/avidity of T cell receptor (TCR) recognition for self-peptide bound to major histocompatibility complex II (self-pMHC) ligands is a distinctive feature of CD4 T regulatory (Treg) cells, including their development in the thymus and maintenance of their suppressive functions in the periphery. Despite such high self-reactivity, however, all thymic-derived peripheral Treg populations are neither homogenous in their phenotype nor uniformly immune-suppressive in their function under steady state condition. We show here that based on the previously defined heterogeneity in the phenotype of peripheral Treg populations, Ly6C expression on Treg marks a lower degree of activation, proliferation, and differentiation status as well as functional incompetence. We also demonstrate that Ly6C expression on Treg in a steady state is either up- or downregulated depending on relative amounts of tonic TCR signals derived from its contacts with self-ligands. Interestingly, peripheral appearance and maintenance of these Ly6C-expressing Treg cells largely differed in an age-dependent manner, with their proportion being continuously increased from perinatal to young adult period but then being gradually declined with age. The reduction of Ly6C+ Treg in the aged mice was not due to their augmented cell death but rather resulted from downregulation of Ly6C expression. The Ly6C downregulation was accompanied by proliferation of Ly6C+ Treg cells and subsequent change into Ly6C- effector Treg with concomitant restoration of immune-suppressive activity. Importantly, we found that this phenotypic and functional change of Ly6C+ Treg is largely driven by conventional effector T cell population. Collectively, these findings suggest a potential cross-talk between peripheral Treg subsets and effector T cells and provides better understanding for Treg homeostasis and function on maintaining self-tolerance

Developmental self-reactivity determines pathogenic Tc17 differentiation potential of naive CD8+ T cells in murine models of inflammation.

The differentiation of naive CD8+ T cells into effector cells is important for establishing immunity. However, the effect of heterogeneous naive CD8+ T cell populations is not fully understood. Here, we demonstrate that steady-state naive CD8+ T cells are composed of functionally heterogeneous subpopulations that differ in their ability to differentiate into type 17 cytotoxic effector cells (Tc17) in a context of murine inflammatory disease models, such as inflammatory bowel disease and graft-versus-host disease. The differential ability of Tc17 differentiation is not related to T-cell receptor (TCR) diversity and antigen specificity but is inversely correlated with self-reactivity acquired during development. Mechanistically, this phenomenon is linked to differential levels of intrinsic TCR sensitivity and basal Suppressor of Mothers Against Decapentaplegic 3 (SMAD3) expression, generating a wide spectrum of Tc17 differentiation potential within naive CD8+ T cell populations. These findings suggest that developmental self-reactivity can determine the fate of naive CD8+ T cells to generate functionally distinct effector populations and achieve immense diversity and complexity in antigen-specific T-cell immune responses

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<p>A relatively high affinity/avidity of T cell receptor (TCR) recognition for self-peptide bound to major histocompatibility complex II (self-pMHC) ligands is a distinctive feature of CD4 T regulatory (Treg) cells, including their development in the thymus and maintenance of their suppressive functions in the periphery. Despite such high self-reactivity, however, all thymic-derived peripheral Treg populations are neither homogenous in their phenotype nor uniformly immune-suppressive in their function under steady state condition. We show here that based on the previously defined heterogeneity in the phenotype of peripheral Treg populations, Ly6C expression on Treg marks a lower degree of activation, proliferation, and differentiation status as well as functional incompetence. We also demonstrate that Ly6C expression on Treg in a steady state is either up- or downregulated depending on relative amounts of tonic TCR signals derived from its contacts with self-ligands. Interestingly, peripheral appearance and maintenance of these Ly6C-expressing Treg cells largely differed in an age-dependent manner, with their proportion being continuously increased from perinatal to young adult period but then being gradually declined with age. The reduction of Ly6C⁺ Treg in the aged mice was not due to their augmented cell death but rather resulted from downregulation of Ly6C expression. The Ly6C downregulation was accompanied by proliferation of Ly6C⁺ Treg cells and subsequent change into Ly6C⁻ effector Treg with concomitant restoration of immune-suppressive activity. Importantly, we found that this phenotypic and functional change of Ly6C⁺ Treg is largely driven by conventional effector T cell population. Collectively, these findings suggest a potential cross-talk between peripheral Treg subsets and effector T cells and provides better understanding for Treg homeostasis and function on maintaining self-tolerance.</p