Breast cancer stem cell RNA‑pulsed dendritic cells enhance tumor cell killing by effector T�cells�

Abstract

Cancer stem cells (CSCs) underpin the resistance of breast cancer (BC) cells to therapy. Dendritic cell (DC)-based treatment is efficacious and safe, but the efficiency of this technique for targeting CSCs in BC treatment requires further investigation. The present study aimed to investigate the ability of DCs pulsed with breast CSC antigens to activate effector lymphocytes for killing BC cells. CD44 + /CD24-CSCs were isolated from BCA55-121, an in-house patient-derived BC cell line, and acquisition of stemness properties was confirmed by upregulated expression of OCT4A and a superior proliferative capacity in colony formation assays compared with whole population of BCA55-121 (BCA55-121-WP). DCs were differentiated from monocytes from peripheral blood of healthy donors and pulsed with CSC total RNA. Maturation of the CSC RNA-pulsed DCs was confirmed by increased expression of CD11c, CD40, CD83, CD86 and HLA-DR, as well as reduced CD14 expression compared with monocytes. Total lymphocytes co-cultured with CSC RNA-pulsed DCs were analyzed by flow cytometry for markers including CD3, CD4, CD8, CD16 and CD56. The results revealed that the co-cultures contained mostly cytotoxic CD8 + T lymphocytes followed by CD4 + T lymphocytes and smaller populations of natural killer (NK) and NKT cells. ELISA was used to measure IFN-γ production, and it was revealed that activated CD4 + and CD8 + lymphocytes produced more IFN-γ compared with naïve T cells, suggesting that CD8 + T cells were effector T cells. CSC RNA was a more efficient antigen source compared with RNA from mixed BC cells for activating tumor antigen-specific killing by T cells. These CSC-specific effector T cells significantly induced BC cell apoptosis at a 20:1 effector T cell:tumor cell ratio. Of note, the breast CSCs cultures demonstrated resistance to effector T cell killing, which was in part due to increased expression of programmed death ligand 1 in the CSC population. The present study highlights the potential use of CSC RNA for priming DCs in modulating an anticancer immune response against BC.

Cancer Stemness-Based Prognostic Immune-Related Gene Signatures in Lung Adenocarcinoma and Lung Squamous Cell Carcinoma

“…After DCs pulsed with breast CSC total RNA, total lymphocytes were cocultured with CSC total RNA-pulsed DCs and populations of lymphocytes and were analyzed with flow cytometry. The results showed that cocultured productions contained cytotoxic CD8 T lymphocytes, CD4 T lymphocytes, NK, and NKT cells ( 47 ). Tumor-associated macrophages, one population of key immune cells in TME, were closely associated with the progression of NSCLC.…”

Exosome‐based cancer stem cell communication: Implication for detecting and eliminating cancer stem cells

“…Interestingly, these CSC-specific effector T cells significantly triggered breast CSC killing. 130 131 Similarly, exosomes isolated from dendritic cells pulsed with CSC-RNA can also be used to mount an effective anti-CSC immune response. These CDE-pulsed dendritic cells have the potential to activate naïve CD8⁺ T cells and CD4⁺ helper T-cells, and B-cells.…”

“…CSC RNA‐pulsed DCs activated cytotoxic CD8 + T lymphocytes, CD4 + T lymphocytes, and also natural killer (NK) and NKT cells. Interestingly, these CSC‐specific effector T cells significantly triggered breast CSC killing 130 . Naseri et al in an in vitro model derived from an HT‐29 colon cancer cell line, showed that exosomes derived from HT‐29 CSCs could be an effective tumor antigen source to efficiently activate DCs to mount CSC‐specific T‐cell responses.…”

The Tumor Microenvironment as a Driving Force of Breast Cancer Stem Cell Plasticity

“…It is known that cell-cell interactions between BCSCs and CD8 + T lymphocytes can impact the killing ability of the latter. One of the main reported immunosuppressive feature of BCSCs consists in programmed death-ligand 1 (PD-L1) expression [ 101 , 102 ], a T-cell inhibitory molecule that binds the cell surface protein PD-1 on effector T cells, causing their exhaustion [ 103 ]. Interestingly, human TNBCs expressing high levels of PD-L1 show higher expression of stemness markers, increased capability to form mammospheres, and more tumorigenic potential compared to PD-L1 low TNBCs [ 104 ].…”