Biological, Functional and Genetic Characterization of Bone Marrow-Derived Mesenchymal Stromal Cells from Pediatric Patients Affected by Acute Lymphoblastic Leukemia

Abstract

Alterations in hematopoietic microenvironment of acute lymphoblastic leukemia patients have been claimed to occur, but little is known about the components of marrow stroma in these patients. In this study, we characterized mesenchymal stromal cells (MSCs) isolated from bone marrow (BM) of 45 pediatric patients with acute lymphoblastic leukemia (ALL-MSCs) at diagnosis (day+0) and during chemotherapy treatment (days: +15; +33; +78), the time points being chosen according to the schedule of BM aspirates required by the AIEOP-BFM ALL 2009 treatment protocol. Morphology, proliferative capacity, immunophenotype, differentiation potential, immunomodulatory properties and ability to support long-term hematopoiesis of ALL-MSCs were analysed and compared with those from 41 healthy donors (HD-MSCs). ALL-MSCs were also genetically characterized through array-CGH, conventional karyotyping and FISH analysis. Moreover, we compared ALL-MSCs generated at day+0 with those isolated during chemotherapy. Morphology, immunophenotype, differentiation potential and in vitro life-span did not differ between ALL-MSCs and HD-MSCs. ALL-MSCs showed significantly lower proliferative capacity (p<0.001) and ability to support in vitro hematopoiesis (p = 0.04) as compared with HD-MSCs, while they had similar capacity to inhibit in vitro mitogen-induced T-cell proliferation (p = N.S.). ALL-MSCs showed neither the typical translocations carried by the leukemic clone (when present), nor other genetic abnormalities acquired during ex vivo culture. Our findings indicate that ALL-MSCs display reduced ability to proliferate and to support long-term hematopoiesis in vitro. ALL-MSCs isolated at diagnosis do not differ from those obtained during treatment.

Altered mesenchymal niche cells impede generation of normal hematopoietic progenitor cells in leukemic bone marrow

“…In this study, we focused on the functional alterations of a major and The ability of T-ALL PαS MSCs to support hematopoietic cell growth in vitro was significantly reduced as assessed by CAFC and LTC-IC assays ( Figure 4A-C), which is consistent with a previous report 34 . However, this finding could be attributed to a defect at either HSC or HPC level.…”

Angiopoietins in the bone marrow microenvironment of acute lymphoblastic leukemia

“…Conforti et al studied the morphological features of MSCs derived from pediatric patients with ALL and demonstrated that MSCs at diagnosis do not differ from those obtained during treatment. 29 However, Mallampati et al 30 who studied a mouse BCR-ABL+ ALL model observed that tyrosine kinase inhibitors induce MSC-mediated resistance and MSCs may play an essential role in activation of an alternative survival signaling pathway in leukemic cells that protects leukemic cells from chemotherapy. The effects of Ang 1 and Ang 2 on tumor angiogenesis have been studied in acute myeloid leukemia (AML), [31][32][33] chronic lymphocytic leukemia, 34 multiple myeloma, 35 and myelodysplastic syndrome (MDS).…”

Bone marrow mesenchymal stromal cells from acute myelogenous leukemia patients demonstrate adipogenic differentiation propensity with implications for leukemia cell support

“…There are now several reports of MSC changes in human hematologic malignancies such as MDS [23,24], acute lymphoblastic leukemia [25], and AML [14,21,[26][27][28]. Some of these reports suggest increased osteogenic potential [14] whereas others have shown increased adipogenic potential [26,29].…”