Lower expression of NOTCH components in peripheral blood mononuclear cells of allogeneic hematopoietic cell transplant patients

ABSTRACT Introduction: Chronic graft-versus-host disease (cGvHD) not only remains the main cause of late mortality after allogeneic hematopoietic cell transplant, but also has the capacity of causing severe organ impairment in those who survive. The Notch, a highly conserved ligand-receptor pathway, is involved in many immunological processes, including inflammatory and regulatory responses. Recently, mouse models have shown that the blockage of canonical Notch signaling prevents GvHD. Objective and Method: Due to the lack of data on the Notch pathway in human chronic GvHD, we sought to study the expression of NOTCH components in primary samples of patients who received allo-HCT and presented active cGvHD or a long-term clinical tolerance to cGvHD. Results: Our results showed a significantly lower expression of NOTCH components in both groups that received allo-HCT, independently of their cGvHD status, when compared to healthy controls. Conclusion: Moreover, there were no differences in gene expression levels between the active cGvHD and clinically tolerant groups. To our knowledge, this is one of the first studies performed in human primary samples and our data indicate that much remains to be learned regarding NOTCH signaling as a new regulator of GvHD.

Lower expression of NOTCH components in peripheral blood mononuclear cells of allogeneic hematopoietic cell transplant patients.

INTRODUCTION: Chronic graft-versus-host disease (cGvHD) not only remains the main cause of late mortality after allogeneic hematopoietic cell transplant, but also has the capacity of causing severe organ impairment in those who survive. The Notch, a highly conserved ligand-receptor pathway, is involved in many immunological processes, including inflammatory and regulatory responses. Recently, mouse models have shown that the blockage of canonical Notch signaling prevents GvHD. OBJECTIVE AND METHOD: Due to the lack of data on the Notch pathway in human chronic GvHD, we sought to study the expression of NOTCH components in primary samples of patients who received allo-HCT and presented active cGvHD or a long-term clinical tolerance to cGvHD. RESULTS: Our results showed a significantly lower expression of NOTCH components in both groups that received allo-HCT, independently of their cGvHD status, when compared to healthy controls. CONCLUSION: Moreover, there were no differences in gene expression levels between the active cGvHD and clinically tolerant groups. To our knowledge, this is one of the first studies performed in human primary samples and our data indicate that much remains to be learned regarding NOTCH signaling as a new regulator of GvHD.

Expression of transforming growth factor ß pathway components in chronic graft-versus-host disease after allogeneic hematopoietic cell transplantation.

Chronic graft-versus-host disease (cGvHD), an immunological complication of allogeneic cell transplantation, is the principal cause of non-relapse mortality and morbidity. Even though advances have been made in understanding the pathophysiology of this disorder, many questions remain. We sought to evaluate gene expression of transforming growth factor ß (TGF-ß) pathway components, through quantitative RT-PCR and PCR array, in patients with cGvHD with different disease activity. We observed an upregulation of SMAD3, BMP2, CDKN1A, IL6, and TGF-ß2 genes in the clinical tolerance group, which had never developed cGvHD, or which had been withdrawn from all immunosuppressive treatments (IST) for at least 1 year. In addition, SMAD5 gene upregulation was observed in cGvHD patients undergoing IST, and ordinal regression showed a correlation between SMAD5 expression and disease severity. Our data support the evidence of the important role of TGF-ß effects in the pathological process of cGvHD.

Molecular effects of the phosphatidylinositol-3-kinase inhibitor NVP-BKM120 on T and B-cell acute lymphoblastic leukaemia.

BACKGROUND: Constitutive activation of the PI3K pathway in T cell acute lymphoblastic leukaemia (T-ALL) has been reported and in a mouse model, PI3K activation, together with MYC, cooperates in Burkitt lymphoma (BL) pathogenesis. We investigated the effects of NVP-BKM120, a potent pan-class I PI3K inhibitor, in lymphoblastic leukaemia cell lines. METHODS: Effects of NVP-BKM120 on cell viability, clonogenicity, apoptosis, cell cycle, cell signalling and autophagy were assessed in vitro on T-ALL (Jurkat and MOLT-4) and BL (Daudi and NAMALWA) cell lines. RESULTS: NVP-BKM120 treatment decreased cell viability and clonogenic growth in all tested cells. Moreover, the drug arrested cell cycling in association with a decrease in Cyclin B1 protein levels, and increased apoptosis. Immunoblotting analysis of cells treated with the drug revealed decreased phosphorylation, in a dose-dependent manner, of AKT, mTOR, P70S6K and 4EBP1, with stable total protein levels. Additionally, we observed a dose-dependent decrease in BAD phosphorylation, in association with augmented BAX:BCL2 ratio. Quantification of autophagy showed a dose-dependent increase in acidic vesicular organelles in all cells tested. CONCLUSION: In summary, our present study establishes that NVP-BKM120 presents an effective antitumour activity against T-ALL and BL cell lines.