cGAS/STING-mediated upregulation of NKG2D ligands in LSCs contributes to enhanced sensitivity to NK cells
Yan Ouyang1, Yilin Qin2, Qianmin Zhang2
1Neonatal/Pediatric Intensive Care Unit, Children's Medical Center, First Affiliated Hospital of Gannan Medical University, Ganzhou, China.
Introduction:
Natural killer (NK) cells-mediated immune surveillance is essential role for tumor recognition and elimination. The binding of NK group 2 member D (NKG2D) ligands to NKG2D receptor is sufficient to activate the NK cells' cytotoxicity against targeted cells. Here we reported that the inhibition of poly (ADP-ribose) polymerase 1 (PARP1) in leukemia stem cells (LSCs) induced the expression of NKG2D ligands through the activation of DNA damage response.
Methods:
Flow cytometry and Quantitative real-time RT-PCR were used to detect the expression levels of NKG2D ligands on cell surface and mRNA levels in leukemia cells, respectively. Cytotoxicity assay was applied to examine the cytotoxic activity of NK cells against leukemia cells. Dual luciferase reporter (DLR) assay was employed to detect the promoter activation of NKG2D ligands. Western blotting was conducted to check the protein expression level.
Results:
Activated ataxia-telangiectasia mutated proteins (ATM) and ɣH2AX foci accumulation were observed under the treatment of PARP inhibitor, leading to the accumulation of damaged DNA. Subsequently, cyclic GMP-AMP synthase (cGAS) was activated, and stimulator of interferon gene (STING) was recruited to promote the downstream signal transduction via TANK-binding kinase-1 (TBK1) and transcription regulatory factor 3 (IRF3). However, the NKG2D ligands induced by PARP inhibitor was reduced in STING or IRF3-knockdown LSCs, indicating that STING and IRF3 were necessary for the regulation of NGK2D ligands in LSCs upon the DNA damage response.
Discussion:
These data indicated that the DNA damage response-mediated cGAS/STING/TBK1/IRF3 signalling pathway played an essential role in modulating NKG2D ligands expression in LSCs.
Insights
Inhibiting poly (ADP-ribose) polymerase 1 (PARP1) in leukemia stem cells (LSCs) boosts natural killer (NK) cell activity. This occurs via the DNA damage response activating the cGAS/STING pathway, increasing NKG2D ligands for tumor elimination.
Area of Science:
- Immunology
- Oncology
- Molecular Biology
Background:
- Natural killer (NK) cells are crucial for tumor surveillance and elimination.
- The NKG2D receptor-ligand interaction activates NK cell cytotoxicity.
- Leukemia stem cells (LSCs) pose a therapeutic challenge due to immune evasion.
Purpose of the Study:
- To investigate the effect of PARP1 inhibition on NKG2D ligand expression in LSCs.
- To elucidate the role of the DNA damage response (DDR) pathway in this process.
- To explore potential therapeutic strategies targeting NK cell-mediated anti-leukemia immunity.
Main Methods:
- PARP1 inhibition in LSCs.
- Flow cytometry and RT-qPCR for NKG2D ligand expression.
- Cytotoxicity assays with NK cells.
- Luciferase reporter assays for promoter activity.
- Western blotting for protein levels.
- Gene knockdown (STING, IRF3) to assess pathway involvement.
Main Results:
- PARP1 inhibition in LSCs induced DNA damage and activated the ATM/ɣH2AX pathway.
- This activation led to cGAS/STING pathway signaling.
- NKG2D ligand expression was upregulated in LSCs upon PARP1 inhibition.
- Upregulation was dependent on STING and IRF3, indicating their necessity in the DDR-mediated pathway.
- NK cell cytotoxicity against LSCs was enhanced.
Conclusions:
- PARP1 inhibition in LSCs triggers a DDR pathway involving cGAS/STING/TBK1/IRF3.
- This pathway modulates NKG2D ligand expression, enhancing NK cell recognition and killing of LSCs.
- Targeting PARP1 and the DDR pathway presents a promising strategy to augment NK cell-based immunotherapy for leukemia.
More Related Videos
09:01Flow Cytometry to Estimate Leukemia Stem Cells in Primary Acute Myeloid Leukemia and in Patient-derived-xenografts, at Diagnosis and Follow Up
Published on: March 26, 2018
10:21Proliferation and Differentiation of Murine Myeloid Precursor 32D/G-CSF-R Cells
Published on: February 21, 2018
Related Concept Videos
01:28Chemotherapy-Induced Nausea and Vomiting: Neurokinin-1 Receptor Antagonists
01:27Cytotoxic T Cells-mediated Immune Response
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
01:01Regulation of Hematopoietic Stem Cells
02:40Cancer Stem Cells and Tumor Maintenance
Cancer stem cells are thought to originate from tissue-specific normal stem cells or progenitor cells. The normal stem cells usually reside in...