The immunomodulatory role of tumor Syndecan-1 (CD138) on ex vivo tumor microenvironmental CD4+ T cell polarization in inflammatory and non-inflammatory breast cancer patients

• Published in: PloS one Vol. 14; no. 5; p. e0217550
• Main Authors: Saleh, Moshira Ezzat, Gadalla, Ramy, Hassan, Hebatallah, Afifi, Ahmed, Götte, Martin, El-Shinawi, Mohamed, Mohamed, Mona Mostafa, Ibrahim, Sherif Abdelaziz
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30.05.2019; Public Library of Science (PLoS)
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Adult; Aged; Biology and Life Sciences; Breast cancer; Breast Neoplasms - genetics; Breast Neoplasms - immunology; Breast Neoplasms - pathology; Calcium-Binding Proteins - genetics; CD4 antigen; CD4-Positive T-Lymphocytes - immunology; Cell adhesion & migration; Cell culture; Cell Polarity - genetics; Chemokines; Correlation; Cytokines; Female; Flow cytometry; Foxp3 protein; Gene expression; Gene Expression Regulation, Neoplastic; Helper cells; Heparan sulfate; Humans; Immunology; Immunomodulation; Immunomodulation - genetics; Immunomodulators; Immunoregulation; Inflammation; Inflammation - genetics; Inflammation - immunology; Inflammation - pathology; Interleukin 17; Interleukin 23; Interleukin 4; Interleukin-23 - genetics; Leukocytes (mononuclear); Lymphocytes; Lymphocytes T; Medicine and Health Sciences; Metastasis; Middle Aged; Neoplasm Proteins - genetics; Peripheral blood mononuclear cells; Polarization; Research and Analysis Methods; Secretome; Syndecan; Syndecan-1 - genetics; Syndecan-1 - immunology; T-Lymphocytes, Regulatory - immunology; Th1 Cells - immunology; Tributaries; Tumor Microenvironment - genetics; Tumor Microenvironment - immunology; Tumors; Zoology; γ-Interferon; Cairo Egypt; United States > US; Giza Egypt; Egypt
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0217550

Herein, we aimed to identify the immunomodulatory role of tumor Syndecan-1 (CD138) in the polarization of CD4+ T helper (Th) subsets isolated from the tumor microenvironment of inflammatory breast cancer (IBC) and non-IBC patients. Lymphocytes and mononuclear cells isolated from the axillary tributaries of non-IBC and IBC patients during modified radical mastectomy were either stimulated with the secretome as indirect co-culture or directly co-cultured with control and Syndecan-1-silenced SUM-149 IBC cells. In addition, peripheral blood mononuclear cells (PBMCs) of normal subjects were used for the direct co-culture. Employing flow cytometry, we analyzed the expression of the intracellular IFN-γ, IL-4, IL-17, and Foxp3 markers as readout for basal and co-cultured Th1, Th2, Th17, and Treg CD4+ subsets, respectively. Our data revealed that IBC displayed a lower basal frequency of Th1 and Th2 subsets than non-IBC. Syndecan-1-silenced SUM-149 cells significantly upregulated only Treg subset polarization of normal subjects relative to controls. However, Syndecan-1 silencing significantly enhanced the polarization of Th17 and Treg subsets of non-IBC under both direct and indirect conditions and induced only Th1 subset polarization under indirect conditions compared to control. Interestingly, qPCR revealed that there was a negative correlation between Syndecan-1 and each of IL-4, IL-17, and Foxp3 mRNA expression in carcinoma tissues of IBC and that the correlation was reversed in non-IBC. Mechanistically, Syndecan-1 knockdown in SUM-149 cells promoted Th17 cell expansion via upregulation of IL-23 and the Notch ligand DLL4. Overall, this study indicates a low frequency of the circulating antitumor Th1 subset in IBC and suggests that tumor Syndecan-1 silencing enhances ex vivo polarization of CD4+ Th17 and Treg cells of non-IBC, whereby Th17 polarization is possibly mediated via upregulation of IL-23 and DLL4. These findings suggest the immunoregulatory role of tumor Syndecan-1 expression in Th cell polarization that may have therapeutic implications for breast cancer.