Biology and Treatment Paradigms in T Cell Acute Lymphoblastic Leukemia in Older Adolescents and Adults

Oncogenic dependency on SWI/SNF chromatin remodeling factors in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is a hematological malignancy arising from immature thymocytes. Unlike well-known oncogenic transcription factors, such as NOTCH1 and MYC, the involvement of chromatin remodeling factors in T-ALL pathogenesis is poorly understood. Here, we provide compelling evidence on how SWI/SNF chromatin remodeling complex contributes to human T-ALL pathogenesis. Integrative analysis of transcriptomic and ATAC-Seq datasets revealed high expression of SMARCA4, one of the subunits of the SWI/SNF complex, in T-ALL patient samples and cell lines compared to normal T cells. Loss of SMARCA protein function resulted in apoptosis induction and growth inhibition in multiple T-ALL cell lines. ATAC-Seq analysis revealed a massive reduction in chromatin accessibility across the genome after the loss of SMARCA protein function. RUNX1 interacts with SMARCA4 protein and co-occupies the same genomic regions. Importantly, the NOTCH1-MYC pathway was primarily affected when SMARCA protein function was impaired, implicating SWI/SNF as a novel therapeutic target.

T-cell acute lymphoblastic leukemia progression is supported by inflammatory molecules including hepatocyte growth factor

T-cell acute lymphoblastic leukemia (T-ALL) is a malignant hematological disorder characterized by an increased proliferation of immature T lymphocytes precursors. T-ALL treatment includes chemotherapy with strong side effects, and patients that undergo relapse display poor prognosis. Although cell-intrinsic oncogenic pathways are well-studied, the tumor microenvironment, like inflammatory cellular and molecular components is less explored in T-ALL. We sought to determine the composition of the inflammatory microenvironment induced by T-ALL, and its role in T-ALL progression. We show in two mouse T-ALL cell models that T-ALLs enhance blood neutrophils and resident monocytes, accompanied with a plasmatic acute secretion of inflammatory molecules. Depleting neutrophils using anti-Ly6G treatment or resident monocytes by clodronate liposomes treatment does not modulate plasmatic inflammatory molecule secretion and mice survival. However, inhibiting the secretion of inflammatory molecules by microenvironment with NECA, an agonist of adenosine receptors, diminishes T-ALL progression enhancing mouse survival. We uncovered Hepatocyte Growth Factor (HGF), T-ALL-driven and the most decreased molecule with NECA, as a potential therapeutic target in T-ALL. Altogether, we identified a signature of inflammatory molecules that can potentially be involved in T-ALL evolution and uncovered HGF/cMET pathway as important to target for limiting T-ALL progression.

Upfront allogeneic hematopoietic stem cell transplantation for adult T-cell acute lymphoblastic leukemia/lymphoma in first complete remission: a single-center study

BACKGROUND

Real-world data on outcomes of upfront allogeneic hematopoietic stem cell transplantation (allo-HCT) for adult T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) patients in first complete remission (CR1) is still lacking.

METHODS

A single center retrospective study was conducted from 94 consecutive patients received their first allo-HCT between 2010 and 2021, which include 76 patients received upfront allo-HCT and 18 patients received allo-HCT in non-upfront settings.

RESULTS

There were no significant differences in most variables. In the upfront allo-HCT group, 52 (68%) patients achieved CR1 with one cycle of induction regimen. 24 (32%) patients achieved CR1 with more than one cycle. In the non-upfront group, there were 14 patients with active disease and 4 patients in second CR before transplant. The majority of patients received antithymocyte globulin-based graft-versus-host disease prophylaxis. Median follow-up time was 51 months for both groups. 5-year overall survival (OS) was 54% in the upfront allo-HCT group. While, in the non-upfront group, 5-year OS were 19% (P = 0.013). 5-year progression free survival in the upfront group was higher than that in the non-upfront group (50% versus 20%, P = 0.02). 5-year cumulative incidence relapse rate was significantly higher in non-upfront group (64% vs. 32%, P = 0.006). While, there was no difference in the 5-year non-relapse mortality (NRM) rate (19% versus 16%, P = 0.56). The most common cause of death was disease progression. In multivariable analysis, non-upfront allo-HCT (hazard ratios (HR) 2.14, P = 0.03) and HCT-CI (≥ 2) (HR 6.07, P = 0.002) were identified to be associated with worse OS. Non-upfront allo-HCT and HCT-CI (≥ 2) were also found to be independent risk factors for higher relapse rate. While, haploidentical-HCT was found to be associated with increased NRM.

CONCLUSIONS

Our study indicated that allo-HCT remains an important curative treatment for adult patients with T-ALL, especially when it was performed in the upfront setting.

Durable responses in acute lymphoblastic leukaemia with the use of FLT3 and IDH inhibitors

Data regarding the use of FMS-like tyrosine kinase 3 (FLT3) and isocitrate dehydrogenase 1/2 (IDH1/2) inhibitors in acute lymphoblastic leukaemia (ALL) are lacking. We identified 14 patients with FLT3- or IDH1/2-mutated ALL. Three early T-cell precursor-ALL patients received FLT3 or IDH2 inhibitors. Patient 1 maintains a complete remission (CR) with enasidenib after intolerance to chemotherapy. Patient 2 maintained a CR for 27 months after treatment with enasidenib for relapsed disease. Patient 3 was treated with venetoclax and gilteritinib at the time of relapse and maintained a CR with gilteritinib for 8 months. These cases suggest that FLT3 and IDH inhibitors could represent a viable therapeutic option for ALL patients with these mutations.

Myb overexpression synergizes with the loss of Pten and is a dependency factor and therapeutic target in T-cell lymphoblastic leukemia

T-lineage acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that accounts for 10%-15% of pediatric and 25% of adult ALL cases. Although the prognosis of T-ALL has improved over time, the outcome of T-ALL patients with primary resistant or relapsed leukemia remains poor. Therefore, further progress in the treatment of T-ALL requires a better understanding of its biology and the development of more effective precision oncologic therapies. The proto-oncogene MYB is highly expressed in diverse hematologic malignancies, including T-ALLs with genomic aberrations that further potentiate its expression and activity. Previous studies have associated MYB with a malignant role in the pathogenesis of several cancers. However, its role in the induction and maintenance of T-ALL remains relatively poorly understood. In this study, we found that an increased copy number of MYB is associated with higher MYB expression levels, and might be associated with inferior event-free survival of pediatric T-ALL patients. Using our previously described conditional Myb overexpression mice, we generated two distinct MYB-driven T-ALL mouse models. We demonstrated that the overexpression of Myb synergizes with Pten deletion but not with the overexpression of Lmo2 to accelerate the development of T-cell lymphoblastic leukemias. We also showed that MYB is a dependency factor in T-ALL since RNA interference of Myb blocked cell cycle progression and induced apoptosis in both human and murine T-ALL cell lines. Finally, we provide preclinical evidence that targeting the transcriptional activity of MYB can be a useful therapeutic strategy for the treatment of T-ALL.

Biological Markers of High-Risk Childhood Acute Lymphoblastic Leukemia

Childhood acute lymphoblastic leukemia (ALL) has witnessed substantial improvements in prognosis; however, a subset of patients classified as high-risk continues to face higher rates of relapse and increased mortality. While the National Cancer Institute (NCI) criteria have traditionally guided risk stratification based on initial clinical information, recent advances highlight the pivotal role of biological markers in shaping the prognosis of childhood ALL. This review delves into the emerging understanding of high-risk childhood ALL, focusing on molecular, cytogenetic, and immunophenotypic markers. These markers not only contribute to unraveling the underlying mechanisms of the disease, but also shed light on specific clinical patterns that dictate prognosis. The paradigm shift in treatment strategies, exemplified by the success of tyrosine kinase inhibitors in Philadelphia chromosome-positive leukemia, underscores the importance of recognizing and targeting precise risk factors. Through a comprehensive exploration of high-risk childhood ALL characteristics, this review aims to enhance our comprehension of the disease, offering insights into its molecular landscape and clinical intricacies in the hope of contributing to future targeted and tailored therapies.

Acute lymphoblastic leukemia in young adults: which treatment?

Despite improvements in survival among pediatric patients with acute lymphoblastic leukemia (ALL), survival outcomes for adolescents and young adults (AYAs) with ALL have lagged. The reasons for the inferior outcomes among AYAs are multifactorial, each presenting unique challenges and requiring novel solutions. First, adverse disease biology is more common among AYAs with ALL. Ongoing trials are investigating novel approaches to treatment, such as incorporating JAK inhibitors for Philadelphia chromosome-like ALL, menin inhibitors for KMT2A-rearranged ALL, and BCL2/BCLXL inhibition for T-cell ALL. Poorer adherence to therapy also impedes improvements in survival outcomes for AYAs with ALL, but early data suggest that technology, both for monitoring and interventions, may be useful in increasing adherence among this population. Finally, better access to clinical trials and collaboration between pediatric and adult centers is critical in advancing the care of AYAs with ALL. Significant improvements have been made over the past decade, but recognizing, understanding, and addressing each of these unique challenges provides hope that the outcomes for AYAs will continue to improve even further.

Cynaropicrin disrupts tubulin and c-Myc-related signaling and induces parthanatos-type cell death in multiple myeloma

The majority of blood malignancies is incurable and has unforeseeable remitting-relapsing paths in response to different treatments. Cynaropicrin, a natural sesquiterpene lactone from the edible parts of the artichoke plant, has gained increased attention as a chemotherapeutic agent. In this study, we investigated the effects of cynaropicrin against multiple myeloma (MM) cells in vitro and assessed its in vivo effectiveness in a xenograft tumor zebrafish model. We showed that cynaropicrin exerted potent cytotoxicity against a panel of nine MM cell lines and two leukemia cell lines with AMO1 being the most sensitive cell line (IC50 = 1.8 ± 0.3 µM). Cynaropicrin (0.8, 1.9, 3.6 µM) dose-dependently reduced c-Myc expression and transcriptional activity in AMO1 cells that was associated with significant downregulation of STAT3, AKT, and ERK1/2. Cell cycle analysis showed that cynaropicrin treatment arrested AMO1 cells in the G2M phase along with an increase in the sub-G0G1 phase after 24 h. With prolonged treatment times, cells accumulated more in the sub-G0G1 phase, implying cell death. Using confocal microscopy, we revealed that cynaropicrin disrupted the microtubule network in U2OS cells stably expressing α-tubulin-GFP. Furthermore, we revealed that cynaropicrin promoted DNA damage in AMO1 cells leading to PAR polymer production by PARP1 hyperactivation, resulting in AIF translocation from the mitochondria to the nucleus and subsequently to a novel form of cell death, parthanatos. Finally, we demonstrated that cynaropicrin (5, 10 µM) significantly reduced tumor growth in a T-cell acute lymphoblastic leukemia (T-ALL) xenograft zebrafish model. Taken together, these results demonstrate that cynaropicrin causes potent inhibition of hematopoietic tumor cells in vitro and in vivo.

Synthesis and anti-tumor activities in human leukemia-derived cells of polyenylpyrroles with a methyl group at the conjugated polyene terminus

To develop novel drugs for treating T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML) which are highly malignant hematological tumors, a series of analogs having a polyenylpyrrole structure of natural compounds (rumbrin and auxarconjugatin B) were synthesized and investigated their structure-activity relationships (SAR) of in vitro anti-T-ALL and anti-AML activities. We obtained three findings: (1) introduction of a methyl group at the conjugated polyene terminus enhanced anti-T-ALL activity, (2) analogs with a 3-chloropyrrole moiety had even higher selectivity for T-ALL cells, and (3) some analogs were effective against AML-derived cells. Among the studied compounds, 3-chloro-2-(8-ethoxycarbonylnona-1,3,5,7-tetraenyl) pyrrole 4e was the most promising candidate of T-ALL- and AML-treating drug. This study provides useful structural information for designing novel drugs treating T-ALL and AML.

Role of chemokines in T-cell acute lymphoblastic Leukemia: From pathogenesis to therapeutic options

T-cell acute lymphoblastic leukemia (T-ALL) is a highly heterogeneous and aggressive subtype of hematologic malignancy, with limited therapeutic options due to the complexity of its pathogenesis. Although high-dose chemotherapy and allogeneic hematopoietic stem cell transplantation have improved outcomes for T-ALL patients, there remains an urgent need for novel treatments in cases of refractory or relapsed disease. Recent research has demonstrated the potential of targeted therapies aimed at specific molecular pathways to improve patient outcomes. Chemokine-related signals, both upstream and downstream, modulate the composition of distinct tumor microenvironments, thereby regulating a multitude of intricate cellular processes such as proliferation, migration, invasion and homing. Furthermore, the progress in research has made significant contributions to precision medicine by targeting chemokine-related pathways. This review article summarizes the crucial roles of chemokines and their receptors in T-ALL pathogenesis. Moreover, it explores the advantages and disadvantages of current and potential therapeutic options that target chemokine axes, including small molecule antagonists, monoclonal antibodies, and chimeric antigen receptor T-cells.

TCF1/LEF1 triggers Wnt-dependent chemokine/cytokine-induced inflammation and cadherin pathways to drive T-ALL cell migration

T-cell acute lymphoblastic leukemia (T-ALL) is a type of aggressive hematologic malignancy. It progresses quickly and it is likely to be fatal within a few months without treatment. Despite the limitations of current clinical therapies, there is an urgent need for novel and targeted therapies. To explore potential targeted therapies, molecular genetic mechanisms of T-ALL metastasis must be uncovered. However, the genes and mechanisms that mediate T-ALL metastasis are largely unknown. Recent insights into T-ALL biology have identified several genes that can be grouped into several targetable signaling pathways. The Wnt/β-catenin signaling pathway is one of the most important pathways. Our work investigated the functions of TCF1 and LEF1 in cell growth and migration mediated by the Wnt signaling pathway. We found that TCF1 and LEF1 knockdown weakly repressed T-ALL cell proliferation but distinctly impaired cell migration. T-ALL metastasis is dependent on cell migration and invasion. Our results displayed that TCF1 and LEF1 regulated T-ALL cell migration by the Wnt-dependent chemokine and cytokine-induced inflammation and cadherin signaling pathways. By transcriptionally regulating these pathways-associated genes, TCF1 and LEF1 inhibited cell adhesion and promoted cell migration and invasion.

Silencing LCN2 enhances RSL3-induced ferroptosis in T cell acute lymphoblastic leukemia

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) is a life-threatening malignancy and therapeutic toxicity remains a huge challenge for survival rates. A novel iron-dependent form of cell death, ferroptosis, shows potentials in cancer therapy. This study aimed to identify ferroptosis-associated hub genes within a proteinprotein interaction (PPI) network.

METHODS

We screened differential expressed genes (DEGs) in GSE46170 dataset and obtained ferroptosis-related genes from FerrDb database. Through overlapping between DEGs and ferroptosis-related genes, ferroptosis-associated DEGs were identified for further PPI network construction. Molecular complex detection (MCODE) algorithm in Cytoscape was employed to determine tightly connected protein clusters. Chord diagram of Gene Ontology (GO) was generated to reveal the potential biological process of hub genes. Through transfection with siRNA of lipocalin 2 (LCN2) into TALL cells, the regulatory role of LCN2 in ferroptosis was investigated.

RESULTS

Venn diagram identified a total of 37 ferroptosis-associated DEGs between GSE46170 and ferroptosis-associated genes, which were mainly enriched in ferroptosis and necroptosis. Based on PPI network analysis, 5 hub genes (LCN2, LTF, HP, SLC40A1 and TFRC) were found. These hub genes were involved in iron ion transport and could distinguish T-ALL from normal individuals. Further experimental studies demonstrated that LCN2 was highly expressed in T-ALL, while silencing LCN2 promoted RSL3-induced ferroptotic cell death in T-ALL cells.

CONCLUSION

This study identified novel ferroptosis-associated hub genes, which shed new insights into the underlying mechanism of ferroptosis in T-ALL and also provide promising therapeutic targets for T-ALL.

Bioinformatics and Raman spectroscopy-based identification of key pathways and genes enabling differentiation between acute myeloid leukemia and T cell acute lymphoblastic leukemia

Acute myeloid leukemia (AML) and T cell acute lymphoblastic leukemia (T-ALL) are two of the most prevalent hematological malignancies diagnosed among adult leukemia patients, with both being difficult to treat and associated with high rates of recurrence and mortality. In the present study, bioinformatics approaches were used to analyze both of these types of leukemia in an effort to identify characteristic gene expression patterns that were subsequently validated via Raman spectroscopy. For these analyses, four Gene Expression Omnibus datasets (GSE13204, GSE51082, GSE89565, and GSE131184) pertaining to acute leukemia were downloaded, and differentially expressed genes (DEGs) were then identified through comparisons of AML and T-ALL patient samples using the R Bioconductor package. Shared DEGs were then subjected to Gene Ontology (GO) enrichment analyses and were used to establish a protein-protein interaction (PPI) network analysis. In total, 43 and 129 upregulated and downregulated DEGs were respectively identified. Enrichment analyses indicated that these DEGs were closely tied to immune function, collagen synthesis and decomposition, inflammation, the synthesis and decomposition of lipopolysaccharide, and antigen presentation. PPI network module clustering analyses further led to the identification of the top 10 significantly upregulated and downregulated genes associated with disease incidence. These key genes were then validated in patient samples via Raman spectroscopy, ultimately confirming the value of these genes as tools that may aid the differential diagnosis and treatment of AML and T-ALL. Overall, these results thus highlight a range of novel pathways and genes that are linked to the incidence and progression of AML and T-ALL, providing a list of important diagnostic and prognostic molecular markers that have the potential to aid in the clinical diagnosis and treatment of these devastating malignancies.

IgD/FcδR is involved in T-cell acute lymphoblastic leukemia and regulated by IgD-Fc-Ig fusion protein

T-cell acute lymphoblastic leukemia (T-ALL) has a poor prognosis as a result of severe immunosuppression and rapid tumor progression with resistance to conventional chemotherapy. Excessive IgD may play a role in T cell activation via IgD Fc receptor (FcδR). Here we aimed to investigate the effects of IgD in T-ALL and demonstrated the potential benefit by targeting IgD/FcδR in T-ALL patients with IgD-Fc-Ig fusion protein. In T-ALL patients' blood samples and cell lines, the level of IgD, the percentage of FcδR expressing cells and the binding affinity were determined by flow cytometry. T cell viability, proliferation and apoptosis were analyzed. A mouse xenograft model was used to evaluate the in vivo effect of IgD-Fc-Ig, an IgD-FcδR blocker. The levels of serum IgD and FcδR were abnormally increased in part of T-ALL patients and IgD could induce over-proliferation and inhibit apoptosis of T-ALL cells in vitro. FcδR was constitutively expressed on T-ALL cells. IgD-Fc-Ig showed similar binding affinity to FcδR and selectively blocked the stimulation effect of IgD on T-ALL cells in vitro. In vivo study exhibited that IgD-Fc-Ig may also have therapeutic benefit. IgD-Fc-Ig administration inhibited human T-ALL growth and extended survival in xenograft T-ALL mice. In conclusion, this work supports the idea of targeting IgD/FcδR in T-ALL patients with excessive IgD. IgD-Fc-Ig fusion protein might be a potential biological drug with high selectivity for T-ALL treatment.

The Successful Implementation of a Modified Pediatric Acute Lymphoblastic Leukemia Protocol to Treat an Elderly Patient With T-cell Lymphoblastic Leukemia: A Case Report

Acute lymphoblastic leukemia (ALL) is a group of hematological malignancies most commonly seen in pediatrics. The disease process localizes in lymphoid organs, the central nervous system, the mediastinum, and bone marrow (BM). The clinical features of T-cell acute lymphoblastic leukemia (T-ALL) in adults include evidence of generalized lymphadenopathy, hepatosplenomegaly, immunosuppression, and hypercalcemia. There is limited research on the efficacy of using modified pediatric treatment regimens in the elderly over the age of 60 with ALL; this case report aims to illustrate the successful treatment of a 67-year-old male patient diagnosed with T-ALL, using a modified Children's Oncology Group (COG) protocol. Through this, it has been shown to be an effective, safe, and efficacious treatment option for our patient.

Chimeric antigen receptor T-cell therapy for T-ALL and AML

Non-B-cell acute leukemia is a term that encompasses T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML). Currently, the therapeutic effectiveness of existing treatments for refractory or relapsed (R/R) non-B-cell acute leukemia is limited. In such situations, chimeric antigen receptor (CAR)-T cell therapy may be a promising approach to treat non-B-cell acute leukemia, given its promising results in B-cell acute lymphoblastic leukemia (B-ALL). Nevertheless, fratricide, malignant contamination, T cell aplasia for T-ALL, and specific antigen selection and complex microenvironment for AML remain significant challenges in the implementation of CAR-T therapy for T-ALL and AML patients in the clinic. Therefore, designs of CAR-T cells targeting CD5 and CD7 for T-ALL and CD123, CD33, and CLL1 for AML show promising efficacy and safety profiles in clinical trials. In this review, we summarize the characteristics of non-B-cell acute leukemia, the development of CARs, the CAR targets, and their efficacy for treating non-B-cell acute leukemia.

Outcomes and prognostic factors of adults with refractory or relapsed T-cell acute lymphoblastic leukemia included in measurable residual disease-oriented trials

Despite high complete remission (CR) rates with frontline therapy, relapses are frequent in adults with T-cell acute lymphoblastic leukemia (T-ALL) with limited salvage options. We analyzed the outcomes and prognostic factors for CR to salvage therapy and overall survival (OS) of patients with R/R T-ALL included in two prospective measurable residual disease-oriented trials. Seventy-five patients (70 relapsed, 5 refractory) were identified. Relapses occurred in bone marrow, isolated or combined in 50 patients, and in the central nervous system (CNS; isolated or combined) in 20. Second CR was attained in 30/75 patients (40%). Treatment with FLAG-Ida and isolated CNS relapse were independently associated with a higher CR rate after first salvage therapy. The median OS was 6.2 (95% confidence interval [CI], 3.9-8.6) months, with a 4-year OS probability of 18% (95% CI, 9%-27%). No differences in survival were observed according to the treatment with hematopoietic stem cell transplantation in patients in CR after first salvage therapy. Multivariable analysis showed a ≥12-month interval between first CR and relapse, CR after first salvage therapy and isolated CNS relapse as favorable prognostic factors for OS with hazard ratios (HR) (95% CI) of 1.931 (1.109-3.362), 2.958 (1.640-5.334), and 2.976 (1.157-7.655), respectively. This study confirms the poor outcomes of adults with R/R T-ALL among whom FLAG-Ida was the best of the rescue therapies evaluated. Late relapse, CR after first rescue therapy and isolated CNS relapse showed prognostic impact on survival. More effective rescue therapies are needed in adults with R/R T-ALL.

LINC00665 promotes the viability, migration and invasion of T cell acute lymphoblastic leukemia cells by targeting miR-101 via modulating PI3K/Akt pathway

T cell acute lymphoblastic leukemia (T-ALL) is a high-risk malignancy. The effects of cancer growth-related Long Intergenic Non-Protein Coding RNA 665 (LINC00665) in T-ALL remained obscure, and therefore further exploration was conducted on that in this study. The expression of LINC00665 in acute myeloid leukemia (LAML) tissues and myeloid tissues was analyzed using Gene Expression Profiling Interactive Analysis (GEPIA) 2. The target microRNA (miR) of LINC00665 was predicted by LncBase Predicted v.2 and verified using dual-luciferase reporter assay. After LINC00665 and miR-101 in T-ALL cells were overexpressed or silenced, the viability, migration and invasion of cell were detected using cell counting kit-8 and Transwell assays. The expressions of LINC00665, miR-101, Cyclin D1, Matrix metalloproteinases (MMP)-2, MMP-9, phosphorylated (p)-phosphatidylinositol 3-kinase (PI3K), PI3K, p-Akt, Akt were detected by quantitative real-time Polymerase Chain Reaction (qRT-PCR) and western blot. High expression of LINC00665 was presented in LAML tissues, the peripheral blood samples from patients with T-ALL and T-ALL cells. Overexpression of LINC00665 promoted the viability, migration and invasion of T-ALL cells and downregulated miR-101 expression, whereas silencing of LINC00665 did oppositely. MiR-101 could competitively bind to LINC00665, and was low-expressed in T-ALL. MiR-101 mimic inhibited viability, migration and invasion of T-ALL cells, and reversed effects of overexpressed LINC00665, whilst miR-101 inhibitor reversed the effects of LINC00665 silencing. Besides, overexpressed LINC00665 upregulated the expressions of Cyclin D1 MMP-2, and MMP-9 and the ratios of p-PI3K/PI3K and p-Akt/Akt, which were reversed by miR-101 mimic. LINC00665 could enhance the viability, migration and invasion abilities of T-ALL cells by targeting miR-101 via activating PI3K/Akt pathway.

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).

T-cell Acute Lymphoblastic Leukemia: A Roadmap to Targeted Therapies

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy characterized by aberrant proliferation of immature thymocytes. Despite an overall survival of 80% in the pediatric setting, 20% of patients with T-ALL ultimately die from relapsed or refractory disease. Therefore, there is an urgent need for novel therapies. Molecular genetic analyses and sequencing studies have led to the identification of recurrent T-ALL genetic drivers. This review summarizes the main genetic drivers and targetable lesions of T-ALL and gives a comprehensive overview of the novel treatments for patients with T-ALL that are currently under clinical investigation or that are emerging from preclinical research.

SIGNIFICANCE

T-ALL is driven by oncogenic transcription factors that act along with secondary acquired mutations. These lesions, together with active signaling pathways, may be targeted by therapeutic agents. Bridging research and clinical practice can accelerate the testing of novel treatments in clinical trials, offering an opportunity for patients with poor outcome.

Facts and Challenges in Immunotherapy for T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL), a T-cell malignant disease that mainly affects children, is still a medical challenge, especially for refractory patients for whom therapeutic options are scarce. Recent advances in immunotherapy for B-cell malignancies based on increasingly efficacious monoclonal antibodies (mAbs) and chimeric antigen receptors (CARs) have been encouraging for non-responding or relapsing patients suffering from other aggressive cancers like T-ALL. However, secondary life-threatening T-cell immunodeficiency due to shared expression of targeted antigens by healthy and malignant T cells is a main drawback of mAb—or CAR-based immunotherapies for T-ALL and other T-cell malignancies. This review provides a comprehensive update on the different immunotherapeutic strategies that are being currently applied to T-ALL. We highlight recent progress on the identification of new potential targets showing promising preclinical results and discuss current challenges and opportunities for developing novel safe and efficacious immunotherapies for T-ALL.