Interleukin-7 signaling as a therapeutic target in acute lymphoblastic leukemia

A novel classification predicts prognosis and drug sensitivity in osteosarcoma based on alterations in gene sets

Osteosarcoma is a cancer originating in the bone cells, specifically in the osteoblasts. Previous studies mainly focused on particular molecules but the whole pathway network. We comprehensively analyzed the enrichment score of each signal pathway and identified a novel classification by 20 machine learning algorithms. Furthermore, differences in tumor immune infiltration cells and drug sensitivity were compared in low and high groups. We identified a model consisting of four signaling pathways that predict the prognosis and the immune status of the tumor microenvironment and drug sensitivity in osteosarcoma patients. The novel classification may be used in clinical applications to predict prognosis and drug sensitivity.

Pediatric T-cell acute lymphoblastic leukemia blast signature and MRD associated immune environment changes defined by single cell transcriptomics analysis

Different driver mutations and/or chromosomal aberrations and dysregulated signaling interactions between leukemia cells and the immune microenvironment have been implicated in the development of T-cell acute lymphoblastic leukemia (T-ALL). To better understand changes in the bone marrow microenvironment and signaling pathways in pediatric T-ALL, bone marrows collected at diagnosis (Dx) and end of induction therapy (EOI) from 11 patients at a single center were profiled by single cell transcriptomics (10 Dx, 5 paired EOI, 1 relapse). T-ALL blasts were identified by comparison with healthy bone marrow cells. T-ALL blast-associated gene signature included SOX4, STMN1, JUN, HES4, CDK6, ARMH1 among the most significantly overexpressed genes, some of which are associated with poor prognosis in children with T-ALL. Transcriptome profiles of the blast cells exhibited significant inter-patient heterogeneity. Post induction therapy expression profiles of the immune cells revealed significant changes. Residual blast cells in MRD+ EOI samples exhibited significant upregulation (P < 0.01) of PD-1 and RhoGDI signaling pathways. Differences in cellular communication were noted in the presence of residual disease in T cell and hematopoietic stem cell compartments in the bone marrow. Together, these studies generate new insights and expand our understanding of the bone marrow landscape in pediatric T-ALL.

MicroRNA mediated gene regulatory circuits leads to machine learning based preliminary detection of Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) can be detected based on morphology, cytochemistry, immunological markers, and cytogenetics. MicroRNAs (miRNAs) influence key biological pathways in multiple haematological malignancies including AML. In this work, we have analysed the miRNome and the transcriptome of normal and AML samples and have identified the significant set of miRNA-target mRNA pairs present within AML- Peripheral Blood and AML- Bone Marrow samples from both tissue and cell lines. The miRNA target genes are further filtered based on their functional significance in AML system. These filtered genes constitute the set of selected miRNA target features, which have been finally used for developing machine learning based prediction tool, 'TbAMLPred' for preliminary detection of AML. This model implements both unsupervised clustering and supervised classification algorithms that would increase the reliability of prediction. Our results show that the selected miRNA target-based features can separate the control and disease samples linearly. Overall, we put forward 'TbAMLPred' for a non-invasive mode of preliminary AML diagnosis in future. Github link for accessing TbAMLPred: https://github.com/zglabDIB/TbAMLPred.

The Complexity of the Tumor Microenvironment and Its Role in Acute Lymphoblastic Leukemia: Implications for Therapies

The microenvironment that surrounds a tumor, in addition to the tumor itself, plays an important role in the onset of resistance to molecularly targeted therapies. Cancer cells and their microenvironment interact closely between them by means of a molecular communication that mutually influences their biological characteristics and behavior. Leukemia cells regulate the recruitment, activation and program of the cells of the surrounding microenvironment, including those of the immune system. Studies on the interactions between the bone marrow (BM) microenvironment and Acute Lymphoblastic Leukemia (ALL) cells have opened a scenario of potential therapeutic targets which include cytokines and their receptors, signal transduction networks, and hypoxia-related proteins. Hypoxia also enhances the formation of new blood vessels, and several studies show how angiogenesis could have a key role in the pathogenesis of ALL. Knowledge of the molecular mechanisms underlying tumor-microenvironment communication and angiogenesis could contribute to the early diagnosis of leukemia and to personalized molecular therapies. This article is part of a Special Issue entitled: Innovative Multi-Disciplinary Approaches for Precision Studies in Leukemia edited by Sandra Marmiroli (University of Modena and Reggio Emilia, Modena, Italy) and Xu Huang (University of Glasgow, Glasgow, United Kingdom).

STAT5: From Pathogenesis Mechanism to Therapeutic Approach in Acute Leukemia

BACKGROUND

Based on the results of multiple studies, multiple signaling pathways is a major cause of resistence to chemotherapy in leukemia cells. Signal transducer and activator of transcription 5 (STAT5) is among these factors; it plays an essential role in proliferation of leukemic cells.

METHODS

We obtained the materials used in our study via PubMed search from 1996 through 2019. The key search terms included "STAT5," "acute leukemia," "leukemogenesis," and "mutation."

RESULTS

On activation, STAT5 not only inhibits apoptosis of leukemic cells via activating the B-cell lymphoma 2 (BCL-2) gene but also inhibits resistance to chemotherapy by enhancing human telomerase reverse transcriptase (hTERT) expression and maintaining telomere length in cells. It has also been shown that a number of mutations in the STAT5 gene and in related genes alter the expression of STAT5.

CONCLUSION

The identification of STAT5 and the factors activated in its up- or downstream expression, affecting its function, contribute to better treatments such as targeted therapy rather than chemotherapy, improving the quality of life patients.

IL-7R is essential for leukemia-initiating cell activity of T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy resulting from the dysregulation of signaling pathways that control intrathymic T-cell development. Relapse rates are still significant, and prognosis is particularly bleak for relapsed patients. Therefore, development of novel therapies specifically targeting pathways controlling leukemia-initiating cell (LIC) activity is mandatory for fighting refractory T-ALL. The interleukin-7 receptor (IL-7R) is a crucial T-cell developmental pathway that is commonly expressed in T-ALL and has been implicated in leukemia progression; however, the significance of IL-7R/IL-7 signaling in T-ALL pathogenesis and its contribution to disease relapse remain unknown. To directly explore whether IL-7R targeting may be therapeutically efficient against T-ALL relapse, we focused on a known Notch1-induced T-ALL model, because a majority of T-ALL patients harbor activating mutations in NOTCH1, which is a transcriptional regulator of IL-7R expression. Using loss-of-function approaches, we show that Il7r-deficient, but not wild-type, mouse hematopoietic progenitors transduced with constitutively active Notch1 failed to generate leukemia upon transplantation into immunodeficient mice, thus providing formal evidence that IL-7R function is essential for Notch1-induced T-cell leukemogenesis. Moreover, we demonstrate that IL-7R expression is an early functional biomarker of T-ALL cells with LIC potential and report that impaired IL-7R signaling hampers engraftment and progression of patient-derived T-ALL xenografts. Notably, we show that IL-7R-dependent LIC activity and leukemia progression can be extended to human B-cell acute lymphoblastic leukemia (B-ALL). These results have important therapeutic implications, highlighting the relevance that targeting normal IL-7R signaling may have in future therapeutic interventions, particularly for preventing T-ALL (and B-ALL) relapse.

Effects of interleukin-7/interleukin-7 receptor on RANKL-mediated osteoclast differentiation and ovariectomy-induced bone loss by regulating c-Fos/c-Jun pathway

To explore the effects of IL-7/IL-7R on the RANKL-mediated osteoclast differentiation in vitro and OVX-induced bone loss in vivo. BMMs and RAW264.7 were transfected with IL-7, IL-7R siRNA, c-Fos siRNA, and c-jun siRNA and later stimulated by RANKL. TRAP and toluidine blue staining were used to observe osteoclast formation and bone resorption, respectively. HE and TRAP staining were used to detect trabecular bone microstructure and osteoclasts of mice, respectively. qRT-PCR and Western blot analysis were used to examine expression. IL-7 unregulated the expression of CTSK, NFATc1, MMP9, and the phosphorylation of p38 and Akt by activating the c-Fos/c-Jun pathway, which increased osteoclast numbers and bone resorption in RANKL-stimulated macrophages. While IL-7R siRNA and c-Fos siRNA decreased the expression, as well as and the phosphorylation of p38 and Akt.IL-7 decreased the BMD and OPG expression in OVX-induced mice and increased the TRAP positive cells, the mRNA expression of c-fos, c-jun, and RANKL, which was contradictory to IL-7R siRNA, and c-Fos siRNA. Furthermore, IL-7R siRNA and c-Fos siRNA caused thicker trabeculae, increased trabecular number, and decreased osteolysis in OVX mice. IL-7/IL-7R can promote RANKL-mediated osteoclast formation and bone resorption by activating the c-Fos/c-Jun pathway, as well as inducing bone loss in OVX mice.