1. Galectin-3 in Prostate Cancer Stem-Like Cells Is Immunosuppressive and Drives Early Metastasis.
- Author
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Caputo S, Grioni M, Brambillasca CS, Monno A, Brevi A, Freschi M, Piras IS, Elia AR, Pieri V, Baccega T, Lombardo A, Galli R, Briganti A, Doglioni C, Jachetti E, and Bellone M
- Subjects
- Adenocarcinoma genetics, Adenocarcinoma immunology, Adenocarcinoma secondary, Animals, Blood Proteins, Cell Line, Tumor, Cell Proliferation, Coculture Techniques, Galectin 3 genetics, Galectins, Gene Expression Regulation, Neoplastic, Humans, Lymphatic Metastasis, Lymphocyte Activation, Lymphocytes, Tumor-Infiltrating immunology, Lymphocytes, Tumor-Infiltrating metabolism, Male, Mice, Inbred C57BL, Mice, Transgenic, Neoplastic Stem Cells immunology, Prostatic Intraepithelial Neoplasia genetics, Prostatic Intraepithelial Neoplasia immunology, Prostatic Intraepithelial Neoplasia secondary, Prostatic Neoplasms genetics, Prostatic Neoplasms immunology, Prostatic Neoplasms pathology, Signal Transduction, Tumor Microenvironment, Adenocarcinoma metabolism, Galectin 3 metabolism, Neoplastic Stem Cells metabolism, Prostatic Intraepithelial Neoplasia metabolism, Prostatic Neoplasms metabolism, Tumor Escape
- Abstract
Galectin-3 (Gal-3) is an extracellular matrix glycan-binding protein with several immunosuppressive and pro-tumor functions. The role of Galectin-3 in cancer stem-like cells (CSCs) is poorly investigated. Here, we show that prostate CSCs also colonizing prostate-draining lymph nodes of transgenic adenocarcinoma of the mouse prostate (TRAMP) mice overexpress Gal-3. Gal-3 contributes to prostate CSC-mediated immune suppression because either Gal-3 silencing in CSCs, or co-culture of CSCs and T cells in the presence of the Gal-3 inhibitor N-Acetyl-D-lactosamine rescued T cell proliferation. N-Acetyl-D-lactosamine also rescued the proliferation of T cells in prostate-draining lymph nodes of TRAMP mice affected by prostate intraepithelial neoplasia. Additionally, Gal-3 impacted prostate CSC tumorigenic and metastatic potential in vivo , as Gal-3 silencing in prostate CSCs reduced both primary tumor growth and secondary invasion. Gal-3 was also found expressed in more differentiated prostate cancer cells, but with different intracellular distribution as compared to CSCs, which suggests different functions of Gal-3 in the two cell populations. In fact, the prevalent nuclear and cytoplasmic distribution of Gal-3 in prostate CSCs made them less susceptible to apoptosis, when compared to more differentiated prostate cancer cells, in which Gal-3 was predominantly intra-cytoplasmic. Finally, we found Gal-3 expressed in human and mouse prostate intraepithelial neoplasia lesions and in metastatic lymph nodes. All together, these findings identify Gal-3 as a key molecule and a potential therapeutic target already in the early phases of prostate cancer progression and metastasis., (Copyright © 2020 Caputo, Grioni, Brambillasca, Monno, Brevi, Freschi, Piras, Elia, Pieri, Baccega, Lombardo, Galli, Briganti, Doglioni, Jachetti and Bellone.)
- Published
- 2020
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