p66Shc Deficiency in Chronic Lymphocytic Leukemia Promotes Chemokine Receptor Expression Through the ROS-Dependent Inhibition of NF-κB

Abstract

The microenvironment of lymphoid organs is central to the pathogenesis of chronic lymphocytic leukemia (CLL). Within it, tumor cells find a favourable niche to escape immunosurveillance and acquire pro-survival signals. We have previously reported that a CLL-associated defect in the expression of the pro-apoptotic and pro-oxidant adaptor p66Shc leads to enhanced homing to and accumulation of leukemic cells in the lymphoid microenvironment. The p66Shc deficiency-related impairment in intracellular reactive oxygen species (ROS) production in CLL cells is causally associated to the enhanced expression of the chemokine receptors CCR2, CXCR3 and CCR7, that promote leukemic cell homing to both lymphoid and non-lymphoid organs, suggesting the implication of a ROS-modulated transcription factor(s). Here we show that the activity of the ROS-responsive p65 subunit of the transcription factor NF-κB was hampered in the CLL-derived cell line MEC-1 expressing a NF-κB-luciferase reporter following treatment with H2O2. Similar results were obtained when intracellular ROS were generated by expression of p66Shc, but not of a ROS-defective mutant, in MEC-1 cells. NF-κB activation was associated with increased expression of the chemokine receptors CCR2, CXCR3 and CCR7. Reconstitution of p66Shc in CLL cells normalized intracellular ROS and hampered NF-κB activation, which led to a decrease in the expression of these homing receptors. Our data provide direct evidence that the p66Shc-deficiency-related ROS depletion in CLL cells concurs to NF-κB hyperactivation and homing receptor overexpression, providing a mechanistic basis for the enhanced ability of these cells to accumulate in the pro-survival lymphoid niche.

Leukemic cell-secreted interleukin-9 suppresses cytotoxic T cell-mediated killing in chronic lymphocytic leukemia

“…p66Shc is a molecular adaptor that promotes apoptosis through an adaptor-independent pro-oxidant activity [21,22], which contributes to the intrinsic apoptosis defects and chemoresistance of CLL cells [17,27,28]. The ROS-elevating, gene-modulating activity of p66Shc also indirectly favours leukemic cell survival by setting an imbalance between the homing and egress receptors that coordinate lymphocyte trafficking, promoting their accumulation in the pro-survival lymphoid niche [50,51]. Here we show that p66Shc deletion in Eμ-TCL1 mice also affects the expression of CLL-critical cytokines such as IL-9 and IL-10 by leukemic cells, which also applies to the p66Shc-deficient CLL cells.…”

How receptor tyrosine kinase‐like orphan receptor 1 meets its partners in chronic lymphocytic leukemia

“…[114][115][116] The expression of NFR2 target genes, such as NAD (P)H quinone oxidoreductase 1 (NAD(P)H quinone oxidoreductase 1), contributes to a drug-resistant phenotype, whose ablation enhanced the sensitivity of CLL cells to be eliminated by drugs that induce ROS production, such venetoclax. 117 Several evidences support that ROR1 recruits PI3K to induce the transformation of phosphatidylinositol 4,5 -bisphosphate (PIP2) to phosphatidylin- activation also activates mTORC1. p62 binds and increases the activation of mTORC1.…”

“…In ROR1‐high CLL cells, Wnt5a promotes the expression of NF‐ κ B target genes and thus a significantly greater amount of p62 activating mTORC1 signaling and NRF2 to promote the expression of reactive oxygen species (ROS) detoxifying enzymes thus protecting tumor cells from drug‐induced oxidative stress 114–116 . The expression of NFR2 target genes, such as NAD(P)H quinone oxidoreductase 1 (NAD(P)H quinone oxidoreductase 1), contributes to a drug‐resistant phenotype, whose ablation enhanced the sensitivity of CLL cells to be eliminated by drugs that induce ROS production, such venetoclax 117 . Several evidences support that ROR1 recruits PI3K to induce the transformation of phosphatidylinositol 4,5 ‐bisphosphate (PIP2) to phosphatidylinositol 3–5 ‐trisphosphate (PIP3), leading to the activation of 3‐phosphoinositide‐dependent protein kinase 1, thus to the phosphorylation of AKT and the activation of NF‐ κ B thereby the accumulation of p62 (in a IKKβ‐dependent manner).…”

New insights into the Lck-NF-κB signaling pathway

“…NF-κB can bind to enhancers and promoters of its target genes, such as matrix metallopeptidase 9 (MMP-9), vascular endothelial growth factor (VEGF), urokinase type plasminogen activator (uPA) and chemokine receptors (CXCR1, CXCR2, CXCR3, CXCR4, CCR2 and CCR7, etc.) that control metastasis, invasion and angiogenesis of cancer cells (Richmond, 2002;Taniguchi and Karin, 2018;Tatangelo et al, 2022). In addition, survival and maturation of B lymphocytes by BAFF/BAFF receptor (BAFFR) are mainly mediated by NF-κB (Zhang et al, 2017).…”