Tumor-associated macrophage (TAM)-secreted CCL22 confers cisplatin resistance of esophageal squamous cell carcinoma (ESCC) cells via regulating the activity of diacylglycerol kinase α (DGKα)/NOX4 axis.

Tumor-associated macrophages (TAMs) are often associated with chemoresistance and resultant poor clinical outcome in solid tumors. Here, we demonstrated that TAMs-released chemokine-C-C motif chemokine 22 (CCL22) in esophageal squamous cell carcinoma (ESCC) stroma was tightly correlated with the chemoresistance of ESCC patients. TAMs-secreted CCL22 was able to block the growth inhibitory and apoptosis-promoting effects of cisplatin on ESCC cells. Mechanistically, CCL22 stimulated intratumoral diacylglycerol kinase α (DGKα) to produce phosphatidic acid (PA), which suppressed the activity of NADPH oxidase 4 (NOX4) and then blocked the overproduction of intratumoral reactive species oxygen (ROS) induced by cisplatin. CCL22 activated DGKα/nuclear factor-κB (NF-κB) axis to upregulate the level of several members of ATP binding cassette (ABC) transporter superfamily, including ABC sub-family G member 4 (ABCG4), ABC sub-family A member 3 (ABCA3), and ABC sub-family A member 5 (ABCA5), to lower the intratumoral concentration of cisplatin. Consequently, these processes induced the cisplatin resistance in ESCC cells. In xenografted models, targeting DGKα with 5'-cholesterol-conjugated small-interfering (si) RNA enhanced the chemosensitivity of cisplatin in ESCC treatment, especially in the context of TAMs. Our data establish the correlation between the TAMs-induced intratumoral metabolic product/ROS axis and chemotherapy efficacy in ESCC treatment and reveal relevant molecular mechanisms.

[Regulation of Baicalin on Growth of Extranodal NK/T Cell Lymphoma Cells through FOXO3/CCL22 Signaling Pathway].

OBJECTIVE: To investigate the effect of baicalin on the growth of extranodal NK/T cell lymphoma (ENKTCL) cells and its related mechanism. METHODS: Normal NK cells and human ENKTCL cells lines SNK-6 and YTS were cultured, then SNK-6 and YTS cells were treated with 5, 10, 20 µmol/L baicalin and set control. Cell proliferation and apoptosis was detected by Edu method and FCM method, respectively, and expressions of BCL-2, Bax, FOXO3 and CCL22 proteins were detected by Western blot. Interference plasmids were designed and synthesized. FOXO3 siRNA interference plasmids and CCL22 pcDNA overexpression plasmids were transfected with PEI transfection reagent. Furthermore, animal models were established for validation. RESULTS: In control group and 5, 10, 20 µmol/L baicalin group, the proliferation rate of SNK-6 cells was (56.17±2.96)%, (51.92±4.63)%, (36.42±1.58)%, and (14.60±2.81)%, respectively, while that of YTS cells was (58.85±2.98)%, (51.38±1.32)%, (34.75±1.09)%, and (15.45±1.10)%, respectively. In control group and 5, 10, 20 µmol/L baicalin group, the apoptosis rate of SNK-6 cells was (5.93±0.74)%, (11.78±0.34)%, (28.46±0.44)%, and (32.40±0.37)%, respectively, while that of YTS cells was (7.93±0.69)%, (16.29±1.35)%, (33.91±1.56)%, and (36.27±1.06)%, respectively. Compared with control group, the expression of BCL-2 protein both in SNK-6 and YTS cells decreased significantly (P<0.001), and the expression of Bax protein increased in SNK-6 cells only when the concentration of baicalin was 20 µmol/L (P<0.001), while that in YTS cells increased in all three concentrations(5, 10, 20 µmol/L) of baicalin (P<0.001). The expression of FOXO3 protein decreased while CCL22 protein increased in ENKTCL cell lines compared with human NK cells (P<0.001), but the expression of FOXO3 protein increased (P<0.01) and CCL22 protein decreased after baicalin treatment (P<0.001). Animal experiments showed that baicalin treatment could inhibit tumor growth. The expression of CCL22 protein in ENKTCL tissue of nude mice treated with baicalin decreased compared with control group (P<0.01), while the FOXO3 protein increased (P<0.05). In addition, FOXO3 silencing resulted in the decrease of FOXO3 protein expression and increase of CCL22 protein expression (P<0.01, P<0.001). CONCLUSION: Baicalin can inhibit proliferation and promote apoptosis of ENKTCL cell lines SNK-6 and YTS, up-regulate the expression of Bax protein, down-regulate the expression of BCL-2 protein, and down-regulate the expression of CCL22 protein mediated by FOXO3. Animal experiment shown that the baicalin can inhibit tumor growth. Baicalin can inhibit the growth and induce apoptosis of ENKTCL cells through FOXO3/CCL22 signaling pathway.

Fulvic Acid Attenuates Atopic Dermatitis by Downregulating CCL17/22.

The main pathogenic factor in atopic dermatitis (AD) is Th2 inflammation, and levels of serum CCL17 and CCL22 are related to severity in AD patients. Fulvic acid (FA) is a kind of natural humic acid with anti-inflammatory, antibacterial, and immunomodulatory effects. Our experiments demonstrated the therapeutic effect of FA on AD mice and revealed some potential mechanisms. FA was shown to reduce TARC/CCL17 and MDC/CCL22 expression in HaCaT cells stimulated by TNF-α and IFN-γ. The inhibitors showed that FA inhibits CCL17 and CCL22 production by deactivating the p38 MAPK and JNK pathways. After 2,4-dinitrochlorobenzene (DNCB) induction in mice with atopic dermatitis, FA effectively reduced the symptoms and serum levels of CCL17 and CCL22. In conclusion, topical FA attenuated AD via downregulation of CCL17 and CCL22, via inhibition of P38 MAPK and JNK phosphorylation, and FA is a potential therapeutic agent for AD.

Role of Chemokine Receptor CCR4 and Regulatory T Cells in Wound Healing of Diabetic Mice.

Wound healing is a well-coordinated process that involves inflammatory mediators and cellular responses; however, if any disturbances are present during this process, tissue repair is impaired. Chronic wounds are one of the serious long-term complications associated with diabetes mellitus. The chemokine receptor CCR4 and its respective ligands, CCL17 and CCL22, are involved in regulatory T cell recruitment and activation in inflamed skin; however, the role of regulatory T cells in wounds is still not clear. Our aim was to investigate the role of CCR4 and regulatory T cells in cutaneous wound healing in diabetic mice. Alloxan-induced diabetic wild- type mice (diabetic) developed wounds that were difficult to heal, differently from CCR4-/- diabetic mice (CCR4-/- diabetic), and also from anti-CCL17/22 or anti-CD25-injected diabetic mice that presented with accelerated wound healing and fewer regulatory T cells in the wound bed. Consequently, CCR4-/- diabetic mice also presented with alteration on T cells population in the wound and draining lymph nodes; on day 14, these mice also displayed an increase of collagen fiber deposition. Still, cytokine levels were decreased in the wounds of CCR4-/- diabetic mice on day 2. Our data suggest that the receptor CCR4 and regulatory T cells negatively affect wound healing in diabetic mice.

Recruitment of IL-27-Producing CD4(+) T Cells and Effect of IL-27 on Pleural Mesothelial Cells in Tuberculous Pleurisy.

BACKGROUND: The numbers of IL-27-producing CD4(+) T cells and the concentration of soluble IL-27 have been found to be increased in tuberculous pleural effusion (TPE). The objective of the present study was to explore the mechanism by which IL-27(+)CD4(+) T cells are recruited into the pleural space, and to explore the impact of IL-27 on pleural mesothelial cells (PMCs). METHODS: The expression profiles of chemokine receptor (CCR) were determined by flow cytometry. The chemoattractant activity of chemokines CCL20 and CCL22 for IL-27(+)CD4(+) T cells in vitro was observed. Effects of IL-27 on wound healing, proliferation and apoptosis of PMCs were also investigated. RESULTS: IL-27(+)CD4(+) T cells in TPE expressed high level of CCR6, medium level of CCR4, and low levels of CCR2, CCR3, CCR5, CCR7, CCR10, and CXCR3. Recruitment of IL-27(+)CD4(+) T cells into TPE could be induced by pleural CCL20 and CCL22. By activating STAT3 signaling, IL-27 significantly improved wound healing and promoted proliferation of PMCs, and completely prevented apoptosis of PMCs induced by IFN-γ. CONCLUSIONS: After being recruited into pleural space by CCL20 or/and CCL22, these pleural IL-27-producing CD4(+) T cells may play important roles in tuberculosis immunity by affecting PMC functions.

In situ prior proliferation of CD4+ CCR6+ regulatory T cells facilitated by TGF-ß secreting DCs is crucial for their enrichment and suppression in tumor immunity.

BACKGROUND: CD4(+)CD25(+) regulatory T cells (Tregs), a heterogeneous population, were enrichment in tumor mass and played an important role in modulating anti-tumor immunity. Recently, we reported a Treg subset, CCR6(+) Tregs but not CCR6(-)Tregs, were enriched in tumor mass and closely related to poor prognosis of breast cancer patients. However, the underlying mechanism remains elusive. Here, we carefully evaluate the enrichment of CCR6(+)Tregs in tumor mass during progression of breast cancer and explore its possible mechanism. METHODOLOGY/PRINCIPAL FINDINGS: The frequency of CCR6(+)Tregs in tumor infiltrating lymphocytes (TILs ) was analyzed at early stage and at late stage of tumor in a murine breast cancer model by FACS respectively. The expansion of CCR6(+)Tregs and their CCR6(-) counterpart in tumor mass were determined by BrdU incorporation assay. The effect and its possible mechanism of tumor-resident antigen presenting cells (APCs) on the proliferation of CCR6(+)Tregs also were evaluated. The role of local expansion of CCR6(+)Tregs in their enrichment and suppression in vivo also was evaluated in adoptive cell transfer assay. We found that the prior enrichment of CCR6(+)Tregs but not CCR6(-)Tregs in tumor mass during progression of murine breast cancer, which was dependent on the dominant proliferation of CCR6(+) Tregs in situ. Further study demonstrated that tumor-resident DCs triggered the proliferation of CCR6(+)Treg cells in TGF-ß dependent manner. Adoptive transfer of CCR6(+)Tregs was found to potently inhibit the function of CD8(+)T cells in vivo, which was dependent on their proliferation and subsequently enrichment in tumor mass. CONCLUSIONS/SIGNIFICANCE: Our finding suggested that CCR6(+) Tregs, a distinct subset of Tregs, exert its predominant suppressive role in tumor immunity through prior in situ expansion, which might ultimately provide helpful thoughts for the designing of Treg-based immunotherapy for tumor in the future.

Sezary syndrome and mycosis fungoides arise from distinct T-cell subsets: a biologic rationale for their distinct clinical behaviors.

Cutaneous T-cell lymphoma (CTCL) encompasses leukemic variants (L-CTCL) such as Sézary syndrome (SS) and primarily cutaneous variants such as mycosis fungoides (MF). To clarify the relationship between these clinically disparate presentations, we studied the phenotype of T cells from L-CTCL and MF. Clonal malignant T cells from the blood of L-CTCL patients universally coexpressed the lymph node homing molecules CCR7 and L-selectin as well as the differentiation marker CD27, a phenotype consistent with central memory T cells. CCR4 was also universally expressed at high levels, and there was variable expression of other skin addressins (CCR6, CCR10, and CLA). In contrast, T cells isolated from MF skin lesions lacked CCR7/L-selectin and CD27 but strongly expressed CCR4 and CLA, a phenotype suggestive of skin resident effector memory T cells. Our results suggest that SS is a malignancy of central memory T cells and MF is a malignancy of skin resident effector memory T cells.

CCL22 recruits CD4-positive CD25-positive regulatory T cells into malignant pleural effusion.

PURPOSE: The aim of this study was to explore the presence of the chemokines CCL22 and CCL17 in malignant pleural effusion, and the chemoattractant activity of these chemokines on CD4-positive CD25-positive Foxp3-positive regulatory T cells infiltrating into the pleural space. EXPERIMENTAL DESIGN: The concentrations of CCL22 and CCL17 in both pleural effusions and sera from 33 patients with lung cancer were determined. Flow cytometry was done to determine T lymphocyte subsets in cell pellets of pleural effusion. Pleural cells were analyzed for the expression of CCL22 and CCL17. The chemoattractant activity of CCL22 for regulatory T cells in vitro and in vivo was also observed. RESULTS: The concentration of CCL22 in malignant pleural effusion was significantly higher than that in the corresponding serum. Pleural fluid from lung cancer patients was chemotactic for regulatory T cells, and this activity was partly blocked by an anti-CCL22, but not by an anti-CCL17 antibody. Intrapleural administration of CCL22 of patients produced a marked progressive influx of regulatory T cells into pleural space. CONCLUSIONS: Compared with serum, CCL22 seemed to be increased in malignant pleural effusion, and could directly induce regulatory T cell infiltration into the pleural space in patients with malignant effusion.