ß3-Adrenoreceptor Blockade Reduces Hypoxic Myeloid Leukemic Cells Survival and Chemoresistance.

ß-adrenergic signaling is known to be involved in cancer progression; in particular, beta3-adrenoreceptor (ß3-AR) is associated with different tumor conditions. Currently, there are few data concerning ß3-AR in myeloid malignancies. Here, we evaluated ß3-AR in myeloid leukemia cell lines and the effect of ß3-AR antagonist SR59230A. In addition, we investigated the potential role of ß3-AR blockade in doxorubicin resistance. Using flow cytometry, we assessed cell death in different in vitro myeloid leukemia cell lines (K562, KCL22, HEL, HL60) treated with SR59230A in hypoxia and normoxia; furthermore, we analyzed ß3-AR expression. We used healthy bone marrow cells (BMCs), peripheral blood mononuclear cells (PBMCs) and cord blood as control samples. Finally, we evaluated the effect of SR59230A plus doxorubicin on K562 and K562/DOX cell lines; K562/DOX cells are resistant to doxorubicin and show P-glycoprotein (P-gp) overexpression. We found that SR59230A increased cancer cell lines apoptosis especially in hypoxia, resulting in selective activity for cancer cells; moreover, ß3-AR expression was higher in malignancies, particularly under hypoxic condition. Finally, we observed that SR59230A plus doxorubicin increased doxorubicin resistance reversion mainly in hypoxia, probably acting on P-gp. Together, these data point to ß3-AR as a new target and ß3-AR blockade as a potential approach in myeloid leukemias.

Defective FOXP3 expression in patients with acute Kawasaki disease and restoration by intravenous immunoglobulin therapy.

OBJECTIVES: The aims of this study were: 1) to investigate forkhead box P3 (FOXP3) expression in patients with Kawasaki disease (KD), exploring possible differences during the acute phase and after defervescence; 2) to evaluate a possible association of the FOXP3 single nucleotide polymorphism (SNP) 543 (SNP ID: rs2232367) with KD. METHODS: FOXP3 expression was evaluated on 8 children with KD and 15 healthy children by flow cytometry and Real-Time polymerase chain reaction (RT-PCR). FOXP3 SNP 543 was genotyped by denaturing high-performance liquid chromatography (DHPLC) and sequencing on DNA samples from 58 additional children with KD and 114 healthy donors. RESULTS: The frequencies of CD4+CD25 +FOXP3+ regulatory T cells were significantly (p=0.0002) lower during the acute phase of KD than in sex- and age-matched healthy donors (median % + SD: 4.8+/-1.3 vs. 7.7+/-1.7) and a similar tendency was revealed for FOXP3 mRNA transcripts (p<0.0001). FOXP3 expression increased significantly, at both protein and mRNA levels, after intravenous immunoglobulin (IVIG) therapy treatment and achieving complete remission of disease (at least 48 hrs; median 9.5 days, range 2-30). Of the 58 patients screened, only one female subject (1.7%) carried the presence of 543 SNP in heterozygosis (C>T; for a total of 1 allele out of 88), with no difference between KD patients and controls (0.0%, 0/203 alleles). CONCLUSIONS: Our data reinforce the notion of an impaired immunoregulation in KD, suggesting also a role of IVIG treatment in modifying the Treg compartment. FOXP3 SNP 543 does not seem to be involved in susceptibility to KD in Italian children.

Th17 transcription factor RORC2 is inversely correlated with FOXP3 expression in the joints of children with juvenile idiopathic arthritis.

OBJECTIVE: To investigate the relationship between interleukin 17 (IL-17) producing T cells (Th17) and CD4+CD25+FOXP3+ regulatory T cells (Tregs) in blood and synovial fluid (SF) of patients with juvenile idiopathic arthritis (JIA). METHODS: Sixty-five children with JIA (18 males and 47 females, median age 6.2 yrs; 45 with oligoarticular and 20 with polyarticular course) and 75 age- and sex-matched healthy controls were studied. Flow cytometry was used to analyze the forkhead box P3 (FOXP3)-positive Treg cells in peripheral blood (PB) and synovial fluid mononuclear cells (SFMC). FOXP3 and retinoic-acid related orphan receptor C isoform 2 (RORC2) messenger RNA (mRNA) were assessed by real-time polymerase chain reaction analysis. Cytokines (IL-17 and Th1/Th2 related cytokines) were measured in culture supernatants of 11 paired PBMC and SFMC activated with PMA and ionomycin. RESULTS: FOXP3+ T cells and FOXP3 mRNA amounts were significantly lower in PB of children with JIA as compared with controls (p = 0.0002 and p = 0.001, respectively) and a higher percentage of Treg cells with concomitant higher level of FOXP3 transcript levels were observed in SF when compared with their PB counterparts (both p < 0.0001). SF CD4+FOXP3+ T cells were characterized by higher amounts of FOXP3 protein per cell when compared with peripheral CD4+FOXP3+ T cells, as revealed by the difference in FOXP3 median fluorescence intensity (median +/- SD, arbitrary units, 54 +/- 22.6 vs 19.5 +/- 4.2; p < 0.001). RORC2 transcript levels were higher in JIA joints when compared with matched PB samples (median fold increase 3.9, p < 0.0001) but negatively correlated with FOXP3 mRNA levels (r = -0.623, p = 0.04). Stimulated SFMC displayed an impaired ability to produce IL-17 when compared with PBMC and, interestingly, an inverse relationship between IL-17 levels and the percentage of CD4+CD25+FOXP3+ SF T cells (r = -0.510, p = 0.047) was seen. CONCLUSION: We demonstrated for the first time an increased synovial expression of the transcription factor of Th17, RORC2, in JIA, and its inverse relationship with FOXP3 mRNA. These results extend research on "Th17" and Tregs in JIA.