Interleukin-7 in T-cell acute lymphoblastic leukemia: an extrinsic factor supporting leukemogenesis?
The malignant transformation and expansion of tumor cells involve both cell-autonomous mechanisms and microenvironment signals that regulate viability, nutrient utilization, metabolic activity and cell growth. In T-cell acute lymphoblastic leukemia (T-ALL), the co-culture of leukemic cells with stroma or the addition of particular cytokines prevents ex vivo spontaneous apoptosis. Interleukin-7 (IL-7), a cytokine produced by thymic and bone marrow stroma, increases the viability and proliferation of T-ALL cells. IL-7 induces the activation of Jak/STAT, MEK/Erk and PI3K/Akt signaling pathways in T-ALL cells. PI3K/Akt is the dominant pathway that mediates the effects of IL-7 on T-ALL. PI3K signaling is required for the induction of Bcl-2, the down-regulation of p27(kip1) and cell cycle progression. PI3K signaling is also required for the expression of the glucose transporter Glut1, uptake of glucose, activation of the metabolic machinery, increase in cell size, and maintenance of mitochondrial integrity. These observations suggest that substrates of molecular pathways activated by microenvironmental factors represent attractive molecular targets for the regulation of the viability and proliferation of T-ALL cells and provide the means for the development of novel treatment strategies.
Barata
Joao T
JT
Tumor Biology Unit, Institute of Molecular Medicine, University of Lisbon Medical School, Lisbon, Portugal. Joao_Barata@fm.ul.pt
Cardoso
Angelo A
AA
Boussiotis
Vassiliki A
VA
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D015851:Interleukin-7 / Q000378:metabolism* / Q000494:pharmacology; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics* / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D015534:Trans-Activators / Q000187:drug effects / Q000378:metabolism
D015851:Interleukin-7; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D015534:Trans-Activators; C494918:AKT1 protein, human