ABSTRACT
Connective tissue growth factor (CTGF/CCN2) has long been associated with human cancers. The role it plays in these neoplasms is diverse and tumour specific. Recurring patterns in clinical outcome, histological desmoplasia and mechanisms of action have been found. When CTGF is overexpressed compared to low-expressing normal tissue or is underexpressed compared to high-expressing normal tissue, the functional outcome favours tumour survival and disease progression. CTGF acts by altering proliferation, drug resistance, angiogenesis, adhesion and migration contributing to metastasis. The pattern of CTGF expression and tumour response helps to clarify the role of this matricellular protein across a multitude of human cancers.
Subject(s)
Connective Tissue Growth Factor/genetics , Gene Expression Regulation, Neoplastic , Neoplasms/genetics , Neoplasms/mortality , Cell Adhesion/genetics , Cell Movement/genetics , Cell Proliferation , Connective Tissue Growth Factor/metabolism , Drug Resistance, Neoplasm/genetics , Humans , Neoplasm Metastasis , Neoplasms/pathology , Neovascularization, Pathologic/genetics , Organ Specificity/genetics , Patient Outcome Assessment , PrognosisABSTRACT
The microenvironments of leukemia and cancer are critical for multiple stages of malignancies, and they are an attractive therapeutic target. While skeletal abnormalities are commonly seen in children with acute lymphoblastic leukemia (ALL) prior to initiating osteotoxic therapy, little is known about the alterations to the bone marrow microenvironment during leukemogenesis. Therefore, in this study, we focused on the development of precursor-B cell ALL (pre-B ALL) in an immunocompetent BCR-ABL1+ model. Here we show that hematopoiesis was perturbed, B lymphopoiesis was impaired, collagen production was reduced, and the number of osteoblastic cells was decreased in the bone marrow microenvironment. As previously found in children with ALL, the leukemia-bearing mice exhibited severe bone loss during leukemogenesis. Leukemia cells produced high levels of receptor activator of nuclear factor κB ligand (RANKL), sufficient to cause osteoclast-mediated bone resorption. In vivo administration of zoledronic acid rescued leukemia-induced bone loss, reduced disease burden and prolonged survival in leukemia-bearing mice. Taken together, we provide evidence that targeting leukemia-induced bone loss is a therapeutic strategy for pre-B ALL.
Subject(s)
Bone Marrow/drug effects , Bone Resorption/drug therapy , Osteoclasts/drug effects , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Tumor Microenvironment/drug effects , Zoledronic Acid/therapeutic use , Animals , Bone Marrow/metabolism , Bone Marrow Cells/drug effects , Bone Marrow Cells/metabolism , Bone Resorption/metabolism , Cell Line , HEK293 Cells , Hematopoiesis/drug effects , Humans , Lymphopoiesis/drug effects , Mice , Mice, Inbred C57BL , Osteoclasts/metabolism , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , RANK Ligand/metabolismABSTRACT
Relapse in pediatric T-cell acute lymphoblastic leukemia (T-ALL) remains a significant clinical problem and is thought to be associated with clonal selection during treatment. In this study we used an established pre-clinical model of induction therapy to increase our understanding of the effect of engraftment and chemotherapy on clonal selection and acquisition of drug resistance in vivo. Immune-deficient mice were engrafted with patient diagnostic specimens and exposed to a repeated combination therapy consisting of vincristine, dexamethasone, L-asparaginase and daunorubicin. Any re-emergence of disease following therapy was shown to be associated with resistance to dexamethasone, no resistance was observed to the other three drugs. Immunoglobulin/T-cell receptor gene rearrangements closely matched those in respective diagnosis and relapse patient specimens, highlighting that these clonal markers do not fully reflect the biological changes associated with drug resistance. Gene expression profiling revealed the significant underlying heterogeneity of dexamethasone-resistant xenografts. Alterations were observed in a large number of biological pathways, yet no dominant signature was common to all lines. These findings indicate that the biological changes associated with T-ALL relapse and resistance are stochastic and highly individual, and underline the importance of using sophisticated molecular techniques or single cell analyses in developing personalized approaches to therapy.