Helios characterized circulating follicular helper T cells with enhanced functional phenotypes and was increased in patients with systemic lupus erythematosus

Helios was related to the immunosuppressive capacity and stability of regulatory T cells. However, the significance of Helios in follicular help T (TFH) and follicular regulatory T (TFR) cells is unclear. This research aimed to clarify the significance of Helios (IKZF2) in TFH and TFR cells and its clinical value in systemic lupus erythematosus (SLE). IKZF2 mRNA in different cell subsets was analyzed. Helios+ percentages in TFH and TFR cells were identified in the peripheral blood of 75 SLE patients and 62 HCs (healthy controls). PD-1 and ICOS expression were compared between Helios+ and Helios- cells. The capacity of TFH cells to secrete IL-21 and TFR cells to secrete IL-10 was measured. Correlation analysis and receiver operating characteristic (ROC) curve analysis were conducted to assess the clinical significance of Helios-related TFH and TFR cell subsets in SLE. There was Helios expression in TFH and TFR cells. PD-1 and ICOS were lower in Helios+ TFR than in Helios- TFR. ICOS was increased in Helios+ TFH cells compared with Helios- TFH cells, and ICOS in Helios+ TFH cells was downregulated in SLE. Helios+ TFH cells secreted more IL-21 than Helios- TFH cells, and Helios+ TFH cells from SLE patients had a stronger IL-21 secretion than HCs. Helios+ TFH percentages were negatively correlated with C3 and C4 and positively related to CRP and SLEDAI, and the AUC of Helios+ TFH to distinguish SLE from HC was 0.7959. Helios characterizes circulating TFH cells with enhanced function. Increased Helios+ TFH cells could reflect the autoimmune status of SLE.

Dual IKZF2 and CK1α degrader targets acute myeloid leukemia cells

Acute myeloid leukemia (AML) is a hematologic malignancy for which several epigenetic regulators have been identified as therapeutic targets. Here we report the development of cereblon-dependent degraders of IKZF2 and casein kinase 1α (CK1α), termed DEG-35 and DEG-77. We utilized a structure-guided approach to develop DEG-35 as a nanomolar degrader of IKZF2, a hematopoietic-specific transcription factor that contributes to myeloid leukemogenesis. DEG-35 possesses additional substrate specificity for the therapeutically relevant target CK1α, which was identified through unbiased proteomics and a PRISM screen assay. Degradation of IKZF2 and CK1α blocks cell growth and induces myeloid differentiation in AML cells through CK1α-p53- and IKZF2-dependent pathways. Target degradation by DEG-35 or a more soluble analog, DEG-77, delays leukemia progression in murine and human AML mouse models. Overall, we provide a strategy for multitargeted degradation of IKZF2 and CK1α to enhance efficacy against AML that may be expanded to additional targets and indications.

Discovery and characterization of a selective IKZF2 glue degrader for cancer immunotherapy

Malignant tumors can evade destruction by the immune system by attracting immune-suppressive regulatory T cells (Treg) cells. The IKZF2 (Helios) transcription factor plays a crucial role in maintaining function and stability of Treg cells, and IKZF2 deficiency reduces tumor growth in mice. Here we report the discovery of NVP-DKY709, a selective molecular glue degrader of IKZF2 that spares IKZF1/3. We describe the recruitment-guided medicinal chemistry campaign leading to NVP-DKY709 that redirected the degradation selectivity of cereblon (CRBN) binders from IKZF1 toward IKZF2. Selectivity of NVP-DKY709 for IKZF2 was rationalized by analyzing the DDB1:CRBN:NVP-DKY709:IKZF2(ZF2 or ZF2-3) ternary complex X-ray structures. Exposure to NVP-DKY709 reduced the suppressive activity of human Treg cells and rescued cytokine production in exhausted T-effector cells. In vivo, treatment with NVP-DKY709 delayed tumor growth in mice with a humanized immune system and enhanced immunization responses in cynomolgus monkeys. NVP-DKY709 is being investigated in the clinic as an immune-enhancing agent for cancer immunotherapy.

Helios Expression in Tumor-Infiltrating Lymphocytes Correlates with Overall Survival of Advanced Gastric Cancer Patients

Immunotherapy is a highly promising approach for the treatment of gastric cancer, the third-leading cause of overall cancer death worldwide. In particular, tumor-infiltrating lymphocytes and peripheral blood mononuclear cells are believed to mediate host immune responses, although this activity may vary depending on the activation status and/ or their microenvironments. Here, we examined the expression of a specific zinc finger transcription factor, Helios (IKZF2), in gastric tumor-infiltrating lymphocytes by immunohistochemistry and the correlation with survival. Segregation of gastric cancer patients into high- vs. low-Helios-expressing tumor-infiltrating lymphocytes showed those with high expression to exhibit longer survival in gastric cancer patients, Helicobacter pylori-infected gastric cancer patients and advanced stage (III–IV) gastric cancer patients. In particular, Helios expression was an independent factor for survival in advanced gastric cancer patients. We performed immunofluorescence staining to detect Helios expression in tumor-infiltrating lymphocytes and peripheral blood mononuclear cells. We found that Helios is expressed more in CD4+ T cells and little in CD8+ T cells in infiltrated lymphocytes in gastric cancer. In summary, we believe that the study of specific characteristics of tumor-infiltrating lymphocytes can delineate the interactions of immune and tumor cells to improve upon immunotherapy strategies.

IKZF2 Drives Leukemia Stem Cell Self-Renewal and Inhibits Myeloid Differentiation

Leukemias exhibit a dysregulated developmental program mediated through both genetic and epigenetic mechanisms. Although IKZF2 is expressed in hematopoietic stem cells (HSCs), we found that it is dispensable for mouse and human HSC function. In contrast to its role as a tumor suppressor in hypodiploid B-acute lymphoblastic leukemia, we found that IKZF2 is required for myeloid leukemia. IKZF2 is highly expressed in leukemic stem cells (LSCs), and its deficiency results in defective LSC function. IKZF2 depletion in acute myeloid leukemia (AML) cells reduced colony formation, increased differentiation and apoptosis, and delayed leukemogenesis. Gene expression, chromatin accessibility, and direct IKZF2 binding in MLL-AF9 LSCs demonstrate that IKZF2 regulates a HOXA9 self-renewal gene expression program and inhibits a C/EBP-driven differentiation program. Ectopic HOXA9 expression and CEBPE depletion rescued the effects of IKZF2 depletion. Thus, our study shows that IKZF2 regulates the AML LSC program and provides a rationale to therapeutically target IKZF2 in myeloid leukemia.

A lack of association between the IKZF2 rs12619285 polymorphism and coronary heart disease

The IKZF2 rs12619285 polymorphism is associated with the eosinophil count, which has multidimensional functions in the pathogenesis of coronary heart disease (CHD). The aim of the present study was to investigate the contribution of the IKZF2 rs12619285 polymorphism to the risk of CHD in a Han Chinese population. In total, 721 CHD cases and 631 non-CHD controls were recruited for an association study of the IKZF2 rs12619285 polymorphism. Genotyping was performed using the melting temperature-shift polymerase chain reaction method. No statistically significant association was observed between the IKZF2 rs12619285 polymorphism and CHD (odds ratio, 1.139, 95% confidence interval, 0.927-1.334; P=0.17). In addition, subgroup analyses by gender or age were unable to identify any association between IKZF2 rs12619285 and CHD (P>0.05), and there was no significant correlation between IKZF2 rs12619285 and the severity of CHD (P>0.05). The power of the case-control study was determined to be 63.3%. In addition, the G allele frequency was calculated as 63.6% in the Han Chinese population, which was similar to the 59.3% recorded for the HapMap Chinese population of Han Chinese individuals living in Beijing, compared with 24.3% in European descendents (HapMap-CEU). Therefore, the results indicated that the IKZF2 rs12619285 polymorphism was not associated with CHD in a Han Chinese population. The discrepancy in the association between rs12619285 and CHD may be due to the ethnic differences between Han Chinese and European populations.