Regulation of PI3K signaling in T-cell acute lymphoblastic leukemia: a novel PTEN/Ikaros/miR-26b mechanism reveals a critical targetable role for PIK3CD

circZNF532 promotes endothelial-to-mesenchymal transition in diabetic retinopathy by recruiting TAF15 to stabilize PIK3CD

Endothelial-to-mesenchymal transition (EndMT) is a pivotal event in diabetic retinopathy (DR). This study explored the role of circRNA zinc finger protein 532 (circZNF532) in regulating EndMT in DR progression. Human retinal microvascular endothelial cells (HRMECs) were exposed to high glucose (HG) to induce the DR cell model. Actinomycin D-treated HRMECs were used to confirm the mRNA stability of phosphoinositide-3 kinase catalytic subunit δ (PIK3CD). The interaction between TATA-box-binding protein-associated factor 15 (TAF15) and circZNF532/PIK3CD was subsequently analyzed using RNA immunoprecipitation (RIP), RNA pull-down. It was found that HG treatment accelerated EndMT process, facilitated cell migration and angiogenesis, and enhanced PIK3CD and p-AKT levels in HRMECs, whereas si-circZNF532 transfection neutralized these effects. Further data showed that circZNF532 recruited TAF15 to stabilize PIK3CD, thus elevating PIK3CD expression. Following rescue experiments suggested that PIK3CD overexpression partially negated the inhibitory effect of circZNF532 silencing on EndMT, migration, and angiogenesis of HG-treated HRMECs. In conclusion, our results suggest that circZNF532 recruits TAF15 to stabilize PIK3CD, thereby facilitating EndMT in DR.

Leveraging altered lipid metabolism in treating B cell malignancies

B cell malignancies, comprising over 80 heterogeneous blood cancers, pose significant prognostic challenges due to intricate oncogenic signaling. Emerging evidence emphasizes the pivotal role of disrupted lipid metabolism in the development of these malignancies. Variations in lipid species, such as phospholipids, cholesterol, sphingolipids, and fatty acids, are widespread across B cell malignancies, contributing to uncontrolled cell proliferation and survival. Phospholipids play a crucial role in initial signaling cascades leading to B cell activation and malignant transformation through constitutive B cell receptor (BCR) signaling. Dysregulated cholesterol and sphingolipid homeostasis support lipid raft integrity, crucial for propagating oncogenic signals. Sphingolipids impact malignant B cell stemness, proliferation, and survival, while glycosphingolipids in lipid rafts modulate BCR activation. Additionally, cancer cells enhance fatty acid-related processes to meet heightened metabolic demands. In obese individuals, the obesity-derived lipids and adipokines surrounding adipocytes rewire lipid metabolism in malignant B cells, evading cytotoxic therapies. Genetic drivers such as MYC translocations also intrinsically alter lipid metabolism in malignant B cells. In summary, intrinsic and extrinsic factors converge to reprogram lipid metabolism, fostering aggressive phenotypes in B cell malignancies. Therefore, targeting altered lipid metabolism has translational potential for improving risk stratification and clinical management of diverse B cell malignancy subtypes.

RNA-seq-based miRNA signature as an independent predictor of relapse in pediatric B-cell acute lymphoblastic leukemia

ABSTRACT

Aberrant micro-RNA (miRNA) expression profiles have been associated with disease progression and clinical outcome in pediatric cancers. However, few studies have analyzed genome-wide dysregulation of miRNAs and messenger RNAs (mRNAs) in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). To identify novel prognostic factors, we comprehensively investigated miRNA and mRNA sequencing (miRNA-seq and mRNA-seq) data in pediatric BCP-ALL samples with poor outcome. We analyzed 180 patients, including 43 matched pairs at diagnosis and relapse. Consensus clustering of miRNA expression data revealed a distinct profile characterized by mainly downregulation of miRNAs (referred to as an miR-low cluster [MLC]). The MLC profile was not associated with any known genetic subgroups. Intriguingly, patients classified as MLC had significantly shorter event-free survival (median 21 vs 33 months; log-rank P = 3 ×10-5). Furthermore, this poor prognosis was retained even in hyperdiploid ALL. This poor prognostic MLC profiling was confirmed in the validation cohort. Notably, non-MLC profiling at diagnosis (n = 9 of 23; Fisher exact test, P = .039) often changed into MLC profiling at relapse for the same patient. Integrated analysis of miRNA-seq and mRNA-seq data revealed that the transcriptional profile of MLC was characterized by enrichment of MYC target and oxidative phosphorylation genes, reduced intron retention, and low expression of DICER1. Thus, our miRNA-mRNA integration approach yielded a truly unbiased molecular stratification of pediatric BCP-ALL cases based on a novel prognostic miRNA signature, which may lead to better clinical outcomes.

Evaluation of MicroRNA as Minimal Residual Disease in Leukemia: Diagnostic and Prognostic Approach: A Review

Various factors are effective in the development of minimal residual disease (MRD), one of which is MicroRNAs (miRNAs). miRNAs and their dysfunction in gene expression have influential role in the pathogenesis of leukemia. Nowadays, treatments that lead to the suppression or replacement of miRNAs have been developed. Focusing on the role of miRNAs in managing the treatment of leukemia, in this review article we have investigated the miRNAs and signaling pathways involved in the process of apoptosis and cell proliferation, as well as miRNAs with oncogenic function in malignant leukemia cells. Among the studied miRNAs, miR-99a, and miR-181a play an essential role in apoptosis, proliferation and oncogenesis via AKT, MAPK, RAS, and mTOR signaling pathways. miR-223 and miR-125a affect apoptosis and oncogenesis via Wnt/B-catenin, PTEN/PI3K, and STAT5/AKT/ERK/Src signaling pathways. miR-100 also affects both apoptosis and oncogenesis; it acts via IGF1 and mTOR signaling pathways.

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.

In vivo activity of the dual PI3Kδ and PI3Kγ inhibitor duvelisib against pediatric acute lymphoblastic leukemia xenografts

BACKGROUND

Acute lymphoblastic leukemia (ALL) remains one of the most common causes of cancer-related mortality in children. Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases, and aberrations in the PI3K pathway are associated with several hematological malignancies, including ALL. Duvelisib (Copiktra) is an orally available, small molecule dual inhibitor of PI3Kδ and PI3Kγ, that is Food and Drug Administration (FDA) approved for the treatment of relapsed/refractory chronic lymphocytic leukemia and small lymphocytic lymphoma. Here, we report the efficacy of duvelisib against a panel of pediatric ALL patient-derived xenografts (PDXs).

PROCEDURES

Thirty PDXs were selected for a single mouse trial based on PI3Kδ (PIK3CD) and PI3Kγ (PIK3CG) expression and mutational status. PDXs were grown orthotopically in NSG (NOD.Cg-Prkdc^scid IL2rg^tm1Wjl /SzJAusb) mice, and engraftment was evaluated by enumerating the proportion of human versus mouse CD45⁺ cells (%huCD45⁺ ) in the peripheral blood. Treatment commenced when the %huCD45⁺ reached greater than or equal to 1%, and events were predefined as %huCD45⁺ greater than or equal to 25% or leukemia-related morbidity. Duvelisib was administered per oral (50 mg/kg, twice daily for 28 days). Drug efficacy was assessed by event-free survival and stringent objective response measures.

RESULTS

PI3Kδ and PI3Kγ mRNA expression was significantly higher in B-lineage than T-lineage ALL PDXs (p-values <.0001). Duvelisib was well-tolerated and reduced leukemia cells in the peripheral blood in four PDXs, but with only one objective response. There was no obvious relationship between duvelisib efficacy and PI3Kδ or PI3Kγ expression or mutation status, nor was the in vivo response to duvelisib subtype dependent.

CONCLUSIONS

Duvelisib demonstrated limited in vivo activity against ALL PDXs.

Mass balance, metabolic disposition, and pharmacokinetics of a novel selective inhibitor of PI3Kδ [14C] SHC014748M in healthy Chinese subjects following oral administration

PURPOSE

SHC014748M is a potent, novel selective PI3Kδ isoform inhibitor and is proposed for the treatment of non-Hodgkin lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma. This study investigated the pharmacokinetics, mass balance, metabolism and excretion of SHC014748M in Chinese male subjects following a single oral dose of 150 mg (100 μCi) [¹⁴C] SHC014748M.

METHODS

Six healthy Chinese male subjects administrated an oral suspension of 150 mg (100 μCi) [¹⁴C] SHC014748M and the samples of blood, urine and feces were collected for measuring. Liquid chromatography-tandem mass spectrometry and liquid scintillation counter were utilized to obtain mass balance and the pharmacokinetic data.

RESULTS

The median T_max for [¹⁴C]-radioactivity was 1.6 ± 0.5 h after the oral administration of [¹⁴C] SHC014748M and the mean C_max was 3863 ± 354 ng Eq./mL in plasma, while the mean C_max, t_1/2 values and AUC_0-∞ values for total radioactivity in whole blood were 2466 ± 518 ng Eq./mL, 32.2 ± 30.5 h and 66,236 ± 44,232 h * ng Eq./mL, respectively. Fecal excretion was proposed as the predominant elimination route, accounting for a mean of 90.68 ± 11.38% of the administered dose, whereas the mean urine excretion was 6.00 ± 1.48% within 336 h post-dose. The proposed major metabolic pathway of [¹⁴C] SHC014748M in the human body were as follows: (I) monooxidation, (II) glucuronide acid conjugation, and (III) monoxide-hydrogenation.

CONCLUSIONS

SHC014748M was absorbed, metabolized and excreted with unchanged SHC014748M as its main circulating component in plasma following oral administration. In addition, it was speculated that fecal excretion was the principal excretion pathway; meanwhile, monohydroxy, glucuronide conjugation, oxygen, and hydrogenation were the major clearance pathways of SHC014748M through urine and/or feces.

TRIAL REGISTRATION

The trial registration number: CTR20202505.

The Promising Role of Non-Coding RNAs as Biomarkers and Therapeutic Targets for Leukemia

Early-stage leukemia identification is crucial for effective disease management and leads to an improvement in the survival of leukemia patients. Approaches based on cutting-edge biomarkers with excellent accuracy in body liquids provide patients with the possibility of early diagnosis with high sensitivity and specificity. Non-coding RNAs have recently received a great deal of interest as possible biomarkers in leukemia due to their participation in crucial oncogenic processes such as proliferation, differentiation, invasion, apoptosis, and their availability in body fluids. Recent studies have revealed a strong correlation between leukemia and the deregulated non-coding RNAs. On this basis, these RNAs are also great therapeutic targets. Based on these advantages, we tried to review the role of non-coding RNAs in leukemia. Here, the significance of several non-coding RNA types in leukemia is highlighted, and their potential roles as diagnostic, prognostic, and therapeutic targets are covered.

Silencing of IRF8 Mediated by m6A Modification Promotes the Progression of T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with a poor prognosis, urging for novel therapeutic targets and treatment strategies. N6-methyladenosine (m6A) is a crucial methylation modification that affects the pathogenesis of leukemia by regulating the mRNA of key genes. Interferon regulatory factor 8 (IRF8) is a crucial transcription factor for hematological lineage commitment, but its role in T-ALL is unclear. Here, IRF8 is shown to suppress T-ALL. The expression of IRF8 is abnormally silenced in patients with T-ALL. Knockout of Irf8 significantly hastens the progression of Notch1-induced T-ALL in vivo. Overexpression of IRF8 suppresses the proliferation and invasion of T-ALL cells by inhibiting the phosphatidylinositol 3-kinase/AKT signaling pathway. The fat mass- and obesity-associated protein (FTO), an m6A demethylase, is responsible for directly binding to m6A sites in 3' untranslated region of IRF8 messenger RNA (mRNA) and inducing mRNA degradation via m6A modification. Targeting the FTO-IRF8 axis is used as a proof of concept therapy; inhibition of FTO's demethylase activity drastically alleviates the proliferation of leukemic cells and prolongs the survival of T-ALL mice by restoring IRF8 expression. This study elucidates the pathogenesis of T-ALL from the perspective of epitranscriptomics and provides new insight into the genetic mechanisms and targeted therapy of T-ALL.

Polyphenols: Chemoprevention and therapeutic potentials in hematological malignancies

Polyphenols are one of the largest plant-derived natural product and they play an important role in plants' defense as well as in human health and disease. A number of them are pleiotropic molecules and have been shown to regulate signaling pathways, immune response and cell growth and proliferation which all play a role in cancer development. Hematological malignancies on the other hand, are cancers of the blood. While current therapies are efficacious, they are usually expensive and with unwanted side effects. Thus, the search for newer less toxic agents. Polyphenols have been reported to possess antineoplastic properties which include cell cycle arrest, and apoptosis via multiple mechanisms. They also have immunomodulatory activities where they enhance T cell activation and suppress regulatory T cells. They carry out these actions through such pathways as PI3K/Akt/mTOR and the kynurenine. They can also reverse cancer resistance to chemotherapy agents. In this review, i look at some of the molecular mechanism of action of polyphenols and their potential roles as therapeutic agents in hematological malignancies. Here i discuss their anti-proliferative and anti-neoplastic activities especially their abilities modulate signaling pathways as well as immune response in hematological malignancies. I also looked at clinical studies done mainly in the last 10-15 years on various polyphenol combination and how they enhance synergism. I recommend that further preclinical and clinical studies be carried out to ensure safety and efficacy before polyphenol therapies be officially moved to the clinics.

miRNA Pattern in Hypoxic Microenvironment of Kidney Cancer—Role of PTEN

MicroRNAs are post-transcriptional regulators of gene expression, and disturbances of their expression are the basis of many pathological states, including cancers. The miRNA pattern in the context of tumor microenvironment explains mechanisms related to cancer progression and provides a potential target of modern therapies. Here we show the miRNA pattern in renal cancer focusing on hypoxia as a characteristic feature of the tumor microenvironment and dysregulation of PTEN, being a major tumor suppressor. Methods comprised the CRSPR/Cas9 mediated PTEN knockout in the Renca kidney cancer cell line and global miRNA expression analysis in both in vivo and in vitro (in normoxic and hypoxic conditions). The results were validated on human cancer models with distinct PTEN status. The increase in miR-210-3p in hypoxia was universal; however, the hypoxia-induced decrease in PTEN was associated with an increase in miR-221-3p, the loss of PTEN affected the response to hypoxia differently by decreasing miR-10b-5p and increasing miR-206-3p. In turn, the complete loss of PTEN induces miR-155-5p, miR-100-5p. Upregulation of miR-342-3p in knockout PTEN occurred in the context of the whole tumor microenvironment. Thus, effective identification of miRNA patterns in cancers must consider the specificity of the tumor microenvironment together with the mutations of key suppressors.

DT7 peptide-modified lecithin nanoparticles co-loaded with γ-secretase inhibitor and dexamethasone efficiently inhibit T-cell acute lymphoblastic leukemia and reduce gastrointestinal toxicity

T-cell acute lymphoblastic leukemia (T-ALL) is a serious hematologic malignancy and glucocorticoid resistance is the main recurrent cause for a high relapsed and death rate. Here, we proposed an effective therapeutic regimen of combining gamma-secretase inhibitors (GSIs) with dexamethasone (DEX) to overcome glucocorticoid resistance. Moreover, the bone marrow targeting DT7 peptide-modified lecithin nanoparticles co-loaded with DEX and GSI (TLnp/D&G) were developed to enhance T-ALL cells recognition and endocytosis. In vitro cytotoxicity studies showed that TLnp/D&G significantly inhibited cell survival and promoted apoptosis of T-ALL cells. Mechanically, we found that GSIs promoted DEX-induced cell apoptosis by two main synergetic mechanisms: 1) GSIs significantly upregulated glucocorticoid receptor (GR) expression in T-ALL and restored the glucocorticoid-induced pro-apoptotic response. 2) Both DEX and GSI synergistically inhibited BCL2 and suppressed the survival of T-ALL cells. Furthermore, in vivo studies demonstrated that TLnp/D&G showed high bone marrow accumulation and better antileukemic efficacy both in leukemia bearing models and in systemic Notch1-induced T-ALL models, with excellent biosafety and reduced gastrointestinal toxicity. Overall, our study provides new strategies for the treatment of T-ALL and promising bone marrow targeting systems with high transformation potential.

Targeting the NOTCH1-MYC-CD44 axis in leukemia-initiating cells in T-ALL

The NOTCH1-MYC-CD44 axis integrates cell-intrinsic and extrinsic signaling to ensure the persistence of leukemia-initiating cells (LICs) in T-cell acute lymphoblastic leukemia (T-ALL) but a common pathway to target this circuit is poorly defined. Bromodomain-containing protein 4 (BRD4) is implicated to have a role in the transcriptional regulation of oncogenes MYC and targets downstream of NOTCH1, and here we demonstrate its role in transcriptional regulation of CD44. Hence, targeting BRD4 will dismantle the NOTCH1-MYC-CD44 axis. As a proof of concept, degrading BRD4 with proteolysis targeting chimera (PROTAC) ARV-825, prolonged the survival of mice in Notch1 mutated patient-derived xenograft (PDX) and genetic models (ΔPTEN) of T-ALL. Single-cell proteomics analysis from the PDX model, demonstrated quantitative reduction of LICs (CD34+ CD7+ CD19−) and downregulation of the NOTCH1-MYC-CD44 axis, along with cell cycle, apoptosis and PI3K/Akt pathways. Moreover, secondary transplantation from PDX and ΔPTEN models of T-ALL, confirmed delayed leukemia development and extended survival of mice engrafted with T-ALL from ARV-825 treated mice, providing functional confirmation of depletion of LICs. Hence, BRD4 degradation is a promising LIC-targeting therapy for T-ALL.

Mechanism of IDH1-R132H mutation in T cell acute lymphoblastic leukemia mouse model via the Notch1 pathway

T-cell acute lymphoblastic leukemia (T-ALL) is a clonal malignant disease. Isocitrate Dehydrogenase 1-R123 (IDH1-R132 H) is related to T-ALL progression. This study explored the role of IDH1-R132H in T-ALL. Molt-4 cells with IDH1-R132H mutation were constructed by retroviral transfection of IDH1-R132H and T-ALL xenotransplantation mouse model was established by injection of Molt-4 cells through the tail vein. Infiltration of the liver, spleen, and bone marrow and the percentage of CD45-positive T-ALL cells in them were detected. Cell proliferation, apoptosis, and invasion were evaluated after the intervention of Notch1, PTEN, or PI3K expression. The leukocyte number was increased, the spleen was enlarged, infiltration in bone marrow, spleen, and liver tissue was worsened and the percentage of hCD45-positive T-ALL cells was increased by IDH1-R132H mutation, which promoted T-ALL deterioration. IDH1-R132H mutation promoted proliferation, invasion, and inhibited apoptosis of T-ALL cells, which were reversed by inhibition of Notch1. IDH1-R132H mutation upregulated HES1 expression and downregulated PTEN expression by activating the Notch1 pathway, while inhibition of Notch1 reversed these changes. PTEN inhibited the PI3K/AKT pathway activation. PTEN overexpression reversed IDH1-R132H mutation effect on promoting malignant behaviors of T-ALL cells. IDH1-R132H mutation inhibited PTEN expression by activating the Notch1/HES1 pathway, activated the PI3K/AKT pathway, thus promoting malignant behaviors of T-ALL cells.

MicroRNAs as Modulators of the Immune Response in T-Cell Acute Lymphoblastic Leukemia

Acute lymphoblastic leukaemia (ALL) is an aggressive haematological tumour driven by the malignant transformation and expansion of B-cell (B-ALL) or T-cell (T-ALL) progenitors. The evolution of T-ALL pathogenesis encompasses different master developmental pathways, including the main role played by Notch in cell fate choices during tissue differentiation. Recently, a growing body of evidence has highlighted epigenetic changes, particularly the altered expression of microRNAs (miRNAs), as a critical molecular mechanism to sustain T-ALL. The immune response is emerging as key factor in the complex multistep process of cancer but the role of miRNAs in anti-leukaemia response remains elusive. In this review we analyse the available literature on miRNAs as tuners of the immune response in T-ALL, focusing on their role in Natural Killer, T, T-regulatory and Myeloid-derived suppressor cells. A better understanding of this molecular crosstalk may provide the basis for the development of potential immunotherapeutic strategies in the leukemia field.

PI3K Targeting in Non-solid Cancer

Despite the therapeutic progress, relapse remains a major problem in the treatment of acute lymphoblastic leukemia (ALL). Most leukemia cells that survive chemotherapy are found in the bone marrow (BM), thus resistance to chemotherapy and other treatments may be partially attributed to pro-survival signaling to leukemic cells mediated by leukemia cell-microenvironment interactions. Adhesion of leukemia cells to BM stromal cells may lead to cell adhesion-mediated drug resistance (CAM-DR) mediating intracellular signaling changes that support survival of leukemia cells. In ALL and chronic lymphocytic leukemia (CLL), adhesion-mediated activation of the PI3K/AKT signaling pathway has been shown to be critical in CAM-DR. PI3K targeting inhibitors have been approved for CLL and have been evaluated preclinically in ALL. However, PI3K inhibition has yet to be approved for clinical use in ALL. Here, we review the role of PI3K signaling for normal hematopoietic and leukemia cells and summarize preclinical inhibitors of PI3K in ALL.

Ikaros Proteins in Tumor: Current Perspectives and New Developments

Ikaros is a zinc finger transcription factor (TF) of the Krüppel family member, which significantly regulates normal lymphopoiesis and tumorigenesis. Ikaros can directly initiate or suppress tumor suppressors or oncogenes, consequently regulating the survival and proliferation of cancer cells. Over recent decades, a series of studies have been devoted to exploring and clarifying the relationship between Ikaros and associated tumors. Therapeutic strategies targeting Ikaros have shown promising therapeutic effects in both pre-clinical and clinical trials. Nevertheless, the increasingly prominent problem of drug resistance targeted to Ikaros and its analog is gradually appearing in our field of vision. This article reviews the role of Ikaros in tumorigenesis, the mechanism of drug resistance, the progress of targeting Ikaros in both pre-clinical and clinical trials, and the potential use of associated therapy in cancer therapy.

A Review of Phosphocreatine 3 Kinase δ Subtype (PI3Kδ) and Its Inhibitors in Malignancy

Most cancer deaths are caused by metastasis. The phosphocreatine 3-kinase (PI3K) family includes the I–III classes, with class I divided into 4 subtypes (α, β, γ, δ); and PI3K signaling participates in the regulatory processes of cell proliferation, differentiation, apoptosis, and glucose transport. Moreover, PI3Ks are modulators of cellular membrane lipids involved in signaling and trafficking events. The PI3Kdelta isoform (PI3Kδ), which is not only specifically expressed in hematopoietic cells, but also in different tumor cell lines, is expressed extensively. The increase in PI3Kδ activity is often associated with a variety of cancers. Currently, the strategy of tumor therapy based on PI3Kδ and its related signaling pathway is developing. Besides its established role in controlling functions in autoimmunity and inflammation, the role of PI3Kδ in tumor and metastasis is not clearly elucidated, with the effects of inhibiting PI3Kδ in several types of tumors also remaining unexplored. In addition, the specific inhibitor of PI3Kδ in tumor progression and metastasis and its underlying mechanism need to be further studied. The purpose of this review is to rationalize the existing functions and mechanisms of PI3Kδ in tumor metastasis and the relationship with hematopoietic cells in cancers as well cross-talking with miRNA, which provides a new theoretical basis and potential therapeutic target for the drug therapy of tumor metastasis.

T-ALL can evolve to oncogene independence

The majority of cases of T-cell acute lymphoblastic leukemia (T-ALL) contain chromosomal abnormalities that drive overexpression of oncogenic transcription factors. However, whether these initiating oncogenes are required for leukemia maintenance is poorly understood. To address this, we developed a tetracycline-regulated mouse model of T-ALL driven by the oncogenic transcription factor Lmo2. This revealed that whilst thymus-resident pre-Leukemic Stem Cells (pre-LSCs) required continuous Lmo2 expression, the majority of leukemias relapsed despite Lmo2 withdrawal. Relapse was associated with a mature phenotype and frequent mutation or loss of tumor suppressor genes including Ikzf1 (Ikaros), with targeted deletion Ikzf1 being sufficient to transform Lmo2-dependent leukemias to Lmo2-independence. Moreover, we found that the related transcription factor TAL1 was dispensable in several human T-ALL cell lines that contain SIL-TAL1 chromosomal deletions driving its overexpression, indicating that evolution to oncogene independence can also occur in human T-ALL. Together these results indicate an evolution of oncogene addiction in murine and human T-ALL and show that loss of Ikaros is a mechanism that can promote self-renewal of T-ALL lymphoblasts in the absence of an initiating oncogenic transcription factor.

MicroRNA as a Prognostic and Diagnostic Marker in T-Cell Acute Lymphoblastic Leukemia

T cell acute lymphoblastic leukemia (T-ALL) is a biologically and genetically heterogeneous disease with a poor prognosis overall and several subtypes. The neoplastic transformation takes place through the accumulation of numerous genetic and epigenetic abnormalities. There are only a few prognostic factors in comparison to B cell precursor acute lymphoblastic leukemia, which is characterized by a lower variability and more homogeneous course. The microarray and next-generation sequencing (NGS) technologies exploring the coding and non-coding part of the genome allow us to reveal the complexity of the genomic and transcriptomic background of T-ALL. miRNAs are a class of non-coding RNAs that are involved in the regulation of cellular functions: cell proliferations, apoptosis, migrations, and many other processes. No miRNA has become a significant prognostic and diagnostic factor in T-ALL to date; therefore, this topic of investigation is extremely important, and T-ALL is the subject of intensive research among scientists. The altered expression of many genes in T-ALL might also be caused by wide miRNA dysregulation. The following review focuses on summarizing and characterizing the microRNAs of pediatric patients with T-ALL diagnosis and their potential future use as predictive factors.

LncRNA SNHG5 upregulation induced by YY1 contributes to angiogenesis via miR-26b/CTGF/VEGFA axis in acute myelogenous leukemia

Acute myelogenous leukemia (AML) is the most common acute leukemia in adults. Despite great progress has been made in this field, the pathogenesis of AML is still not fully understood. We report here the biological role of lncRNA small nucleolar RNA host gene 5 (SNHG5) in the pathogenesis of AML and the underlying mechanisms. The results showed that lncRNA SNHG5 was highly expressed in AML cancer cell lines. In vitro studies displayed that inhibition of SNHG5 with shRNA resulted in suppression of survival, cell cycle progression, migration/invasion of AML and capacity of adhesion and angiogenesis in human umbilical vein endothelial cells. Mechanistic studies revealed a SNHG5/miR-26b/connective tissue growth factor (CTGF)/vascular endothelial growth factor A (VEGFA) axis in the regulation of AML angiogenesis. Finally, Yin Yang 1 (YY1) was found to transactivate and interact with SNHG5 promoter, leading to the upregulation of SNHG5 in AML. Collectively, upregulation of lncRNA SNHG5 mediated by YY1, activates CTGF/VEGFA via targeting miR-26b to regulate angiogenesis of AML. Our work provides new insights into the molecular mechanisms of AML.

Transcriptional Regulation of PIK3CD and PIKFYVE in T-Cell Acute Lymphoblastic Leukemia by IKAROS and Protein Kinase CK2

IKAROS, encoded by the IKZF1 gene, is a DNA-binding protein that functions as a tumor suppressor in T cell acute lymphoblastic leukemia (T-ALL). Recent studies have identified IKAROS’s novel function in the epigenetic regulation of gene expression in T-ALL and uncovered many genes that are likely to be directly regulated by IKAROS. Here, we report the transcriptional regulation of two genes, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD) and phosphoinositide kinase, FYVE-type zinc finger containing (PIKFYVE), by IKAROS in T-ALL. PIK3CD encodes the protein p110δ subunit of phosphoinositide 3-kinase (PI3K). The PI3K/AKT pathway is frequently dysregulated in cancers, including T-ALL. IKAROS binds to the promoter regions of PIK3CD and PIKFYVE and reduces their transcription in primary T-ALL. Functional analysis demonstrates that IKAROS functions as a transcriptional repressor of both PIK3CD and PIKFYVE. Protein kinase CK2 (CK2) is a pro-oncogenic kinase that is overexpressed in T-ALL. CK2 phosphorylates IKAROS, impairs IKAROS’s DNA-binding ability, and functions as a repressor of PIK3CD and PIKFYVE. CK2 inhibition results in increased IKAROS binding to the promoters of PIK3CD and PIKFYVE and the transcriptional repression of both these genes. Overall, the presented data demonstrate for the first time that in T-ALL, CK2 hyperactivity contributes to PI3K signaling pathway upregulation, at least in part, through impaired IKAROS transcriptional regulation of PIK3CD and PIKFYVE. Targeting CK2 restores IKAROS’s regulatory effects on the PI3K oncogenic signaling pathway.

Pomalidomide restores immune recognition of primary effusion lymphoma through upregulation of ICAM-1 and B7-2

Pomalidomide (Pom) is an immunomodulatory drug that has efficacy against Kaposi’s sarcoma, a tumor caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). Pom also induces direct cytotoxicity in primary effusion lymphoma (PEL), a B-cell malignancy caused by KSHV, in part through downregulation of IRF4, cMyc, and CK1α as a result of its interaction with cereblon, a cellular E3 ubiquitin ligase. Additionally, Pom can reverse KSHV-induced downregulation of MHCI and co-stimulatory immune surface molecules ICAM-1 and B7-2 on PELs. Here, we show for the first time that Pom-induced increases in ICAM-1 and B7-2 on PEL cells lead to an increase in both T-cell activation and NK-mediated cytotoxicity against PEL. The increase in T-cell activation can be prevented by blocking ICAM-1 and/or B7-2 on the PEL cell surface, suggesting that both ICAM-1 and B7-2 are important for T-cell co-stimulation by PELs. To gain mechanistic insights into Pom’s effects on surface markers, we generated Pom-resistant (PomR) PEL cells, which showed about 90% reduction in cereblon protein level and only minimal changes in IRF4 and cMyc upon Pom treatment. Pom no longer upregulated ICAM-1 and B7-2 on the surface of PomR cells, nor did it increase T-cell and NK-cell activation. Cereblon-knockout cells behaved similarly to the pomR cells upon Pom-treatment, suggesting that Pom’s interaction with cereblon is necessary for these effects. Further mechanistic studies revealed PI3K signaling pathway as being important for Pom-induced increases in these molecules. These observations provide a rationale for the study of Pom as therapy in treating PEL and other KSHV-associated tumors.

Primary effusion lymphoma (PEL) is an aggressive B-cell lymphoma caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). KSHV encodes various genes that enable infected cells to evade recognition and elimination by the immune system. PEL cells are poorly recognized by T-cells and NK cells, partly due to KSHV-induced downregulation of immune stimulatory surface molecules ICAM-1 and B7-2. We previously found that a cereblon-binding immunomodulatory drug pomalidomide (Pom) can restore the levels of these markers on PELs. Here, we show that the increases in ICAM-1 and B7-2 induced by Pom leads to a functional increase in the recognition and killing of PELs by both T-cells and NK cells. Further, exposure of both the PEL cells and T-cells to Pom lead to an even higher T-cell stimulation providing strong evidence that Pom could help PEL patients by providing specific immune-stimulatory effect. We further perform mechanistic studies and show that Pom’s cellular binding partner cereblon as well as the PI3K pathway are important for Pom-mediated increases in these surface markers.

The Emerging Roles of Autophagy-Related MicroRNAs in Cancer

Autophagy is a conserved catabolic process involving the degradation and recycling of damaged biomacromolecules or organelles through lysosomal-dependent pathways and plays a crucial role in maintaining cell homeostasis. Consequently, abnormal autophagy is associated with multiple diseases, such as infectious diseases, neurodegenerative diseases and cancer. Currently, autophagy is considered to be a dual regulator in cancer, functioning as a suppressor in the early stage while supporting the growth and metastasis of cancer cells in the later stage and may also produce therapeutic resistance. MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression at the post-transcriptional level by silencing targeted mRNA. MiRNAs have great regulatory potential for several fundamental biological processes, including autophagy. In recent years, an increasing number of studies have linked miRNA dysfunction to the growth, metabolism, migration, metastasis, and responses of cancer cells to therapy. Therefore, the study of autophagy-related miRNAs in cancer will provide insights into cancer biology and lead to the development of novel anti-cancer strategies. In the present review, we summarise the current knowledge of miRNA dysregulation during autophagy in cancer, focusing on the relationship between autophagy and miRNAs, and discuss their involvement in cancer biology and cancer treatment.

Tumor-suppressive microRNA-551b-3p targets H6PD to inhibit gallbladder cancer progression

Gallbladder cancer (GBC) is a highly malignant cancer with poor prognosis. Extensive studies have reported the vital functionality of several microRNAs (miRNAs) in numerous human cancers, including GBC. Microarray analysis has identified the differentially expressed miR-551b-3p in GBC. Therefore, this study aims to validate the underlying mechanism by which miR-551b-3p participated in epithelial-mesenchymal transition (EMT), invasion and migration of GBCs. Bioinformatic analysis predicted the binding of miR-551b-3p to H6PD. We validated the reduced miR-551b-3p expression and increased H6PD expression in the GBC tissues and GBC cell lines. Artificial modulation of miR-551b-3p and H6PD (down- and upregulation) was conducted to explore their roles in EMT, invasive, and migratory abilities of GBCs, and the tumor-bearing mice were used to determine tumor growth. Overexpression of miR-551b-3p or silencing of H6PD was observed to suppress the expressions of N-cadherin and vimentin, and to promote the expression of E-cadherin, along with reduced invasive and migratory ability of GBCs. Mechanistically, miR-551b-3p could evidently target and inhibit the expression of H6PD. Moreover, in vivo experiments substantiated the tumor-inhibiting activities of miR-551b-3p in nude mice. Conjointly, our study suggests that overexpression of miR-551b-3p inhibited the EMT, migration, and invasion of GBCs by inhibiting the expression of H6PD, indicating that miR-551b-3p may serve as a potential target for future development of therapeutic strategies for GBC.

Long noncoding RNA DLEU2 predicts a poor prognosis and enhances malignant properties in laryngeal squamous cell carcinoma through the miR-30c-5p/PIK3CD/Akt axis

Long noncoding RNAs (lncRNAs) have been identified as potential prognostic tools and therapeutic biomarkers for a variety of human cancers. However, the functional roles and underlying mechanisms of key lncRNAs affecting laryngeal squamous cell carcinomas (LSCCs) are largely unknown. Here, we adopted a novel subpathway strategy based on the lncRNA-mRNA profiles from the Cancer Genome Atlas (TCGA) database and identified the lncRNA deleted in lymphocytic leukemia 2 (DLEU2) as an oncogene in the pathogenesis of LSCCs. We found that DLEU2 was significantly upregulated and predicted poor clinical outcomes in LSCC patients. In addition, ectopic overexpression of DLEU2 promoted the proliferation and migration of LSCC cells both in vivo and in vitro. Mechanistically, DLEU2 served as a competing endogenous RNA to regulate PIK3CD expression by sponging miR-30c-5p and subsequently activated the Akt signaling pathway. As a target gene of DLEU2, PIK3CD was also upregulated and could predict a poor prognosis in LSCC patients. In conclusion, we found that the novel LSCC-related gene DLEU2 enhances the malignant properties of LSCCs via the miR-30c-5p/PIK3CD/Akt axis. DLEU2 and its targeted miR-30c-5p/PIK3CD/Akt axis may represent valuable prognostic biomarkers and therapeutic targets for LSCCs.

Role of PI3K/AKT pathway in cancer: the framework of malignant behavior

Given that the PI3K/AKT pathway has manifested its compelling influence on multiple cellular process, we further review the roles of hyperactivation of PI3K/AKT pathway in various human cancers. We state the abnormalities of PI3K/AKT pathway in different cancers, which are closely related with tumorigenesis, proliferation, growth, apoptosis, invasion, metastasis, epithelial-mesenchymal transition, stem-like phenotype, immune microenvironment and drug resistance of cancer cells. In addition, we investigated the current clinical trials of inhibitors against PI3K/AKT pathway in cancers and found that the clinical efficacy of these inhibitors as monotherapy has so far been limited despite of the promising preclinical activity, which means combinations of targeted therapy may achieve better efficacies in cancers. In short, we hope to feature PI3K/AKT pathway in cancers to the clinic and bring the new promising to patients for targeted therapies.

MiR-29b-3p cooperates with miR-29c-3p to affect the malignant biological behaviors in T-cell acute lymphoblastic leukemia via TFAP2C/GPX1 axis

Mounting evidence has illustrated the tumor regulatory roles of microRNAs (miRNAs) in T-cell acute lymphoblastic leukemia (T-ALL), a malignant carcinoma originated from T-cell precursors. However, the possible regulation mechanisms underlying miR-29b/29c-3p in T-ALL have not been interrogated yet. The aim of our study was to probe the association and possible molecular mechanism of miR-29b/29c-3p and Glutathione Peroxidase 1 (GPX1), a predicted highly expressed gene in acute myeloid leukemia (LAML) tissues on the cancer genome atlas (TCGA) website. In our paper, it was observed that GPX1 was relatively overexpressed in T-ALL cells, compared with normal T cells. Loss-of-function assays demonstrated that GPX1 knockdown inhibited the proliferation and activated the apoptosis in T-ALL cells. Then miR-29b/29c-3p was confirmed to regulate GPX1 mRNA and protein expression via decreasing Transcription Factor AP-2 Gamma (TFAP2C) expression. In summary, miR-29b-3p and miR-29c-3p targeted TFAP2C so as to repress GPX1 transcription, thereafter inhibiting GPXA expression. In the end, rescue experiments proved the whole regulation mechanism of miR-29b/29c-3p in T-ALL. Overall, the miR-29b/29c-3p -TFAP2C-GPX1 axis helped us to have a better understanding of T-ALL pathogenesis.

Linear and circular PVT1 in hematological malignancies and immune response: two faces of the same coin

Non coding RNAs (ncRNAs) have emerged as regulators of human carcinogenesis by affecting the expression of key tumor suppressor genes and oncogenes. They are divided into short and long ncRNAs, according to their length. Circular RNAs (circRNAs) are included in the second group and were recently discovered as being originated by back-splicing, joining either single or multiple exons, or exons with retained introns. The human Plasmacytoma Variant Translocation 1 (PVT1) gene maps on the long arm of chromosome 8 (8q24) and encodes for 52 ncRNAs variants, including 26 linear and 26 circular isoforms, and 6 microRNAs. PVT1 genomic locus is 54 Kb downstream to MYC and several interactions have been described among these two genes, including a feedback regulatory mechanism. MYC-independent functions of PVT1/circPVT1 have been also reported, especially in the regulation of immune responses. We here review and discuss the role of both PVT1 and circPVT1 in the hematopoietic system. No information is currently available concerning their transforming ability in hematopoietic cells. However, present literature supports their cooperation with a more aggressive and/or undifferentiated cell phenotype, thus contributing to cancer progression. PVT1/circPVT1 upregulation through genomic amplification or rearrangements and/or increased transcription, provides a proliferative advantage to malignant cells in acute myeloid leukemia, acute promyelocytic leukemia, Burkitt lymphoma, multiple myeloma (linear PVT1) and acute lymphoblastic leukemia (circPVT1). In addition, PVT1 and circPVT1 regulate immune responses: the overexpression of the linear form in myeloid derived suppressor cells induced immune tolerance in preclinical tumor models and circPVT1 showed immunosuppressive properties in myeloid and lymphoid cell subsets. Overall, these recent data on PVT1 and circPVT1 functions in hematological malignancies and immune responses reflect two faces of the same coin: involvement in cancer progression by promoting a more aggressive phenotype of malignant cells and negative regulation of the immune system as a novel potential therapy-resistance mechanism.

Acidic leucine-rich nuclear phosphoprotein-32A expression contributes to adverse outcome in acute myeloid leukemia

Background

Acidic leucine-rich nuclear phosphoprotein-32A (ANP32A) is a novel regulator of histone H3 acetylation and promotes leukemogenesis in acute myeloid leukemia (AML). However, its prognostic value in AML remains unclear.

Methods

In this study, we evaluated the prognostic significance of ANP32A expression using two independent large cohorts of cytogenetically normal AML (CN-AML) patients. Multivariable analysis in CN-AML group was also presented. Based on the ANP32A expression, its related genes, dysregulation of pathways, interaction network analysis between microRNAs and target genes, as well as methylation analysis were performed to unveil the complex functions behind ANP32A.

Results

Here we demonstrated overexpression of ANP32A was notably associated with unfavorable outcome in two independent cohorts of CN-AML patients (OS: P=0.012, EFS: P=0.005, n=185; OS: P=0.041, n=232), as well as in European Leukemia Net (ELN) Intermediate-I group (OS: P=0.018, EFS: P=0.045, n=115), National Comprehensive Cancer Network (NCCN) Intermediate Risk AML group (OS: P=0.048, EFS: P=0.039, n=225), and non-M3 AML group (OS: P=0.034, EFS: P=0.011, n=435). Multivariable analysis further validated ANP32A as a high-risk factor in CN-AML group. Multi-omics analysis presented overexpression of ANP32A was associated with aberrant expression of oncogenes and tumor suppressor, up/down-regulation of metabolic and immune-related pathways, dysregulation of microRNAs, and hypomethylation on CpG island and 1st Exon regions.

Conclusions

We proved ANP32A as a novel, potential unfavorable prognosticator and therapeutic target for AML.

The role of microRNAs in acute lymphoblastic leukaemia: From biology to applications

MicroRNAs (miRNAs) that are characterized by small, noncoding RNA have an essential role in the pathogenesis of human diseases, including cancer. Furthermore, miRNAs, as a new paradigm of epigenetic regulators, play an important role in normal development and cellular function. This literature review summarizes the recurrent mechanism of gene regulation through miRNAs and, consequently, the impact of regulated genes on different cellular processes, including proliferation, metastasis, prognosis, and apoptosis. Additionally, what is important to note is that the expression of miRNAs in various cancer cells is different, and miRNAs have various target genes in various cancers. Accordingly, a proper understanding of gene regulation by miRNAs contributes to new perspectives in miRNA-based therapeutic strategies. SIGNIFICANCE OF THE STUDY: MiRNAs are considered as a crucial regulator of gene expression. The genes also play an important role in the expression of miRNAs; as a result, there is a relationship between them. In recent years, targeted therapy with miRNAs has been a significant challenge. Studying the mechanisms through which miRNAs regulate various cancer cell processes, including apoptosis, proliferation, and metastasis, is very critical in the treatment of cancer through miRNAs. Definitely, a proper understanding of the impacts of aberrant expression of miRNAs on cancer cell processes leads to new therapeutic strategies in the targeted therapy with miRNAs.

Poly (ADP-ribosylation) of HMGB1 facilitates its acetylation and promotes HMGB1 translocation-associated chemotherapy-induced autophagy in leukaemia cells

Acute lymphoblastic leukaemia (ALL) is one of the most common and curable types of cancer in paediatric patients. However, chemotherapeutic resistance is a difficult but common obstacle when treating leukaemia in the clinical setting. Studies have demonstrated that drug resistance is partly attributable to autophagy induced by multiple chemotherapeutic agents. As an evolutionarily conserved non-histone chromatin-binding protein, high mobility group box protein 1 (HMGB1) is considered to be an important factor in autophagy, and regulates autophagy at multiple levels via different subcellular localisations. In the present study, it was revealed that chemotherapeutic drugs induced autophagy in leukaemia cells and that translocation of HMGB1 from the nucleus to the cytoplasm is an important molecular event in this process. It was further demonstrated that poly (ADP-ribosylation) of HMGB1 facilitates its acetylation, thereby inducing HMGB1 translocation and ultimately promoting chemotherapy-induced autophagy in leukaemic cells. Targeted HMGB1 translocation may overcome chemotherapy-induced autophagy in leukaemia.

New advances in targeting aberrant signaling pathways in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive disorder characterized by malignant transformation of immature progenitors primed towards T-cell development. Over the past 15 years, advances in the molecular characterization of T-ALL have uncovered oncogenic key drivers and crucial signaling pathways of this disease, opening new chances for the development of novel therapeutic strategies. Currently, T-ALL patients are still treated with aggressive therapies, consisting of high dose multiagent chemotherapy. To minimize and overcome the unfavorable effects of these regimens, it is critical to identify innovative targets and test selective inhibitors of such targets. Major efforts are being made to develop small molecules against deregulated signaling pathways, which sustain T-ALL cell growth, survival, metabolism, and drug-resistance. This review will focus on recent improvements in the understanding of the signaling pathways involved in the pathogenesis of T-ALL and on the challenging opportunities for T-ALL targeted therapies.

MicroRNAs and their involvement in T-ALL: A brief overview

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy in which the transformed clone is arrested during T-cell development. Several genetic and epigenetic events have been implicated in this transformation. MicroRNAs (miRNAs) are small, non-coding RNAs that primarily function as endogenous translational repressors of protein-coding genes. The involvement of miRNAs in the regulation of cancer progression is well-established, namely by down-regulating the expression of key oncogenes or tumor suppressors and thereby preventing or promoting tumorigenesis, respectively. Similar to other cancers, several miRNA genes have been identified and implicated in the context of T-ALL. In this review we focused on the most studied microRNAs associated with T-ALL pathogenesis.

The role of aurora A and polo-like kinases in high-risk lymphomas

High-risk lymphomas (HRLs) are associated with dismal outcomes and remain a therapeutic challenge. Recurrent genetic and molecular alterations, including c-myc expression and aurora A kinase (AAK) and polo-like kinase-1 (PLK1) activation, promote cell proliferation and contribute to the highly aggressive natural history associated with these lymphoproliferative disorders. In addition to its canonical targets regulating mitosis, the AAK/PLK1 axis directly regulates noncanonical targets, including c-myc. Recent studies demonstrate that HRLs, including T-cell lymphomas and many highly aggressive B-cell lymphomas, are dependent upon the AAK/PLK1 axis. Therefore, the AAK/PLK1 axis has emerged as an attractive therapeutic target in these lymphomas. In addition to reviewing these recent findings, we summarize the rationale for targeting AAK/PLK1 in high-risk and c-myc-driven lymphoproliferative disorders.

The Key Roles of PTEN in T-Cell Acute Lymphoblastic Leukemia Development, Progression, and Therapeutic Response

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive blood cancer that comprises 10–15% of pediatric and ~25% of adult ALL cases. Although the curative rates have significantly improved over the past 10 years, especially in pediatric patients, T-ALL remains a challenge from a therapeutic point of view, due to the high number of early relapses that are for the most part resistant to further treatment. Considerable advances in the understanding of the genes, signaling networks, and mechanisms that play crucial roles in the pathobiology of T-ALL have led to the identification of the key drivers of the disease, thereby paving the way for new therapeutic approaches. PTEN is critical to prevent the malignant transformation of T-cells. However, its expression and functions are altered in human T-ALL. PTEN is frequently deleted or mutated, while PTEN protein is often phosphorylated and functionally inactivated by casein kinase 2. Different murine knockout models recapitulating the development of T-ALL have demonstrated that PTEN abnormalities are at the hub of an intricate oncogenic network sustaining and driving leukemia development by activating several signaling cascades associated with drug-resistance and poor outcome. These aspects and their possible therapeutic implications are highlighted in this review.

The identification of key genes in nasopharyngeal carcinoma by bioinformatics analysis of high-throughput data

Nasopharyngeal carcinoma (NPC) is a common pattern of regional malignancy in the south of China, especially in Guangdong province. The development of computerized tomography (CT) technology and the improvement of radiotherapy scheme can improve the survival rate of NPC patients. However, the prevalence and recurrence rate of NPC are increasing every year. It is urgent for us to uncover the molecular mechanism of NPC. In this study, we used scientific information retrieval from the GEO (gene expression omnibus) database to download the GSE12452, which contained 41 samples, including 31 nasopharyngeal carcinoma samples and 10 control samples. With the help of GO (gene ontology) analysis, KEGG (kyoto encyclopedia of genes and genomes) analysis, PPI (protein-protein interaction) network model construction, and WGCNA (weighted gene co-expression network analysis), we found 6896 differentially expressed genes, which affected the biological processes included cell cycle process, DNA metabolic process, DNA repairing, immune response, cell activation, regulation of immune system process, inflammatory response. The 20 hub genes present in front of us are SYK, PIK3CG, FYN, ACACB, LRRK2, RIPK4, RAC2, PIK3CD, PTPRC, LCR, RAD51, MAD2L1, CDK1, PCNA, GMPS, CCNB1, GAPDH, CCNA2, RFC4, TOP2A. In the future, these are the areas where we need to focus on the molecular mechanism of NPC.

Targeting PI3K Signaling in Acute Lymphoblastic Leukemia

Adhesion of acute lymphoblastic leukemia (ALL) cells to bone marrow stroma cells triggers intracellular signals regulating cell-adhesion-mediated drug resistance (CAM-DR). Stromal cell protection of ALL cells has been shown to require active AKT. In chronic lymphocytic leukemia (CLL), adhesion-mediated activation of the PI3K/AKT pathway is reported. A novel FDA-approved PI3Kδ inhibitor, CAL-101/idelalisib, leads to downregulation of p-AKT and increased apoptosis of CLL cells. Recently, two additional PI3K inhibitors have received FDA approval. As the PI3K/AKT pathway is also implicated in adhesion-mediated survival of ALL cells, PI3K inhibitors have been evaluated preclinically in ALL. However, PI3K inhibition has yet to be approved for clinical use in ALL. Here, we review the role of PI3K in normal hematopoietic cells, and in ALL. We focus on summarizing targeting strategies of PI3K in ALL.

Differential Co-expression and Regulatory Network Analysis Uncover the Relapse Factor and Mechanism of T Cell Acute Leukemia

The pediatric T cell acute lymphoblastic leukemia (T-ALL) still remains a cancer with worst prognosis for high recurrence. Massive studies were conducted for the leukemia relapse based on diagnosis and relapse paired samples. However, the initially diagnostic samples may contain the relapse information and mechanism, which were rarely studied. In this study, we collected mRNA and microRNA (miRNA) data from initially diagnosed pediatric T-ALL samples with their relapse or remission status after treatment. Integrated differential co-expression and miRNA-transcription factor (TF)-gene regulatory network analyses were used to reveal the possible relapse mechanisms for pediatric T-ALL. We detected miR-1246/1248 and NOTCH2 served as key nodes in the relapse network, and they combined with TF WT1/SOX4/REL to form regulatory modules that influence the progress of T-ALL. A regulatory loop miR-429-MYCN-MFHAS1 was found potentially associated with the remission of T-ALL. Furthermore, we proved miR-1246/1248 combined with NOTCH2 could promote cell proliferation in the T-ALL cell line by experiments. Meanwhile, analysis based on the miRNA-drug relationships demonstrated that drugs 5-fluorouracil, ascorbate, and trastuzumab targeting miR-1246 could serve as potential supplements for the standard therapy. In conclusion, our findings revealed the potential molecular mechanisms of T-ALL relapse by the combination of co-expression and regulatory network, and they provide preliminary clues for precise treatment of T-ALL patients.

Polymerase-mediated ultramutagenesis in mice produces diverse cancers with high mutational load

Mutations underlie all cancers, and their identification and study are the foundation of cancer biology. We describe what we believe to be a novel approach to mutagenesis and cancer studies based on the DNA polymerase ε (POLE) ultramutator phenotype recently described in human cancers, in which a single amino acid substitution (most commonly P286R) in the proofreading domain results in error-prone DNA replication. We engineered a conditional PoleP286R allele in mice. PoleP286R/+ embryonic fibroblasts exhibited a striking mutator phenotype and immortalized more efficiently. PoleP286R/+ mice were born at Mendelian ratios but rapidly developed lethal cancers of diverse lineages, yielding the most cancer-prone monoallelic model described to date, to our knowledge. Comprehensive whole-genome sequencing analyses showed that the cancers were driven by high base substitution rates in the range of human cancers, overcoming a major limitation of previous murine cancer models. These data establish polymerase-mediated ultramutagenesis as an efficient in vivo approach for the generation of diverse animal cancer models that recapitulate the high mutational loads inherent to human cancers.

Biological Aspects of mTOR in Leukemia

The mammalian target of rapamycin (mTOR) is a central processor of intra- and extracellular signals, regulating many fundamental cellular processes such as metabolism, growth, proliferation, and survival. Strong evidences have indicated that mTOR dysregulation is deeply implicated in leukemogenesis. This has led to growing interest in the development of modulators of its activity for leukemia treatment. This review intends to provide an outline of the principal biological and molecular functions of mTOR. We summarize the current understanding of how mTOR interacts with microRNAs, with components of cell metabolism, and with controllers of apoptotic machinery. Lastly, from a clinical/translational perspective, we recapitulate the therapeutic results in leukemia, obtained by using mTOR inhibitors as single agents and in combination with other compounds.

MiR-26b-3p regulates osteoblast differentiation via targeting estrogen receptor α

BACKGROUND

Understanding of the molecular mechanisms of miRNAs involved in osteoblast differentiation is important for the treatment of bone-related diseases.

METHODS

MC3T3-E1 cells were induced to osteogenic differentiation by culturing with bone morphogenetic protein 2 (BMP2). After transfected with miR-26b-3p mimics or inhibitors, the osteogenic differentiation of MC3T3-E1 cells was detected by ALP and ARS staining. Cell viability was analyzed by MTT. The expressions of miR-26b-3p and osteogenic related markers and signaling were examined by qPCR and western blot. Direct binding of miR-26b-3p and ER-α were determined by dual luciferase assay.

RESULTS

miR-26b-3p was significantly down-regulated during osteoblast differentiation. Overexpression of miR-26b-3p inhibited osteoblast differentiation, while inhibition of miR-26b-3p enhanced osteoblast differentiation. Further studies demonstrated miR-26b-3p inhibited the expression of estrogen receptor α (ER-α) by directly targeting to the CDS region of ER-α mRNA. Overexpression of ER-α rescued the suppression effects of miR-26b-3p on osteoblast differentiation, while knockdown of ER-α reversed the upregulation of osteoblast differentiation induced by knockdown of miR-26b-3p.

CONCLUSION

Our study demonstrates that miR-26b-3p suppresses osteoblast differentiation of MC3T3-E1 cells via directly targeting ER-α.

MicroRNA-26b suppresses tumorigenicity and promotes apoptosis in small cell lung cancer cells by targeting myeloid cell leukemia 1 protein

The aim of this study was to investigate the role of microRNA-26b (miR-26b) in regulating the proliferation, migration, and apoptosis of small cell lung cancer (SCLC) cells. First, we examined the expression level of miR-26b in human normal fetal lung fibroblasts (NFLFs) and three SCLC cell lines NCI-H466, NCI-H1688, and NCI-H196. In the following experiments, the three SCLC cell lines were transfected with miR-26b mimic and inhibitor. Cell growth and survival, as well as migration and invasion capacities were determined by MTT, colony formation, Transwell migration and invasion, and wound healing assays. Cell apoptosis, production of reactive oxygen species, and mitochondrial membrane potential were also measured in the three cell lines following various treatments. As a result, we found that the level of miR-26b was significantly lower in SCLC cells than in NFLFs. Additionally, transfection with miR-26b mimic could inhibit proliferation, colony formation, and migration, as well as induce apoptosis in these SCLC cell lines; while miR-26b inhibitor showed the opposite effects. Further mechanistic experiment revealed that miR-26b could suppress the expression of myeloid cell leukemia 1 protein (Mcl-1) and the 3'-untranslated region (3'-UTR) of Mcl-1 may be the direct binding site of miR-26b, suggesting that the effect of miR-26b may be mediated by targeting Mcl-1. Collectively, our findings offer a new insight into the role of miR-26b in the pathogenesis of SCLC, and provide primary evidence supporting the potential of miR-26b-based therapy for the treatment of SCLC.

Therapeutic Targeting of mTOR in T-Cell Acute Lymphoblastic Leukemia: An Update

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive blood malignancy that arises from the clonal expansion of transformed T-cell precursors. Although T-ALL prognosis has significantly improved due to the development of intensive chemotherapeutic protocols, primary drug-resistant and relapsed patients still display a dismal outcome. In addition, lifelong irreversible late effects from conventional therapy are a growing problem for leukemia survivors. Therefore, novel targeted therapies are required to improve the prognosis of high-risk patients. The mechanistic target of rapamycin (mTOR) is the kinase subunit of two structurally and functionally distinct multiprotein complexes, which are referred to as mTOR complex 1 (mTORC1) and mTORC2. These two complexes regulate a variety of physiological cellular processes including protein, lipid, and nucleotide synthesis, as well as autophagy in response to external cues. However, mTOR activity is frequently deregulated in cancer, where it plays a key oncogenetic role driving tumor cell proliferation, survival, metabolic transformation, and metastatic potential. Promising preclinical studies using mTOR inhibitors have demonstrated efficacy in many human cancer types, including T-ALL. Here, we highlight our current knowledge of mTOR signaling and inhibitors in T-ALL, with an emphasis on emerging evidence of the superior efficacy of combinations consisting of mTOR inhibitors and either traditional or targeted therapeutics.

Long non-coding RNA PVT1 as a novel candidate for targeted therapy in hematologic malignancies

Cancerous cells show resistance to various forms of therapy, so applying up to the minute targeted therapy is crucial. For this purpose, long non-coding RNA PVT1 as shown by recent studies is an important oncogene that interacts with vital cellular signaling pathways and different proteins such as c-Myc, NOP2 and LATS2. Due to the enormous role of long non-coding RNAs in development of leukemias, we aimed to show the role of PVT1 knock-down on fate of different hematologic cell lines. owing to this matter, various experiments such as Real-time PCR, cell cycle analysis and apoptosis assay were performed. Meanwhile, proliferation rate by CFSE, protein expression of c-Myc and hTERT by western blot and flow cytometry analysis were investigated. Our results demonstrated that PVT1 knock-down results in c-Myc degradation, proliferation down-regulation, induction of apoptosis and G0/G1 arrest. Simultaneously, for the first time, we posited the relation between this oncogene with hTERT that reduced after PVT1 knock-down. Considering these results, long non-coding RNA PVT1 may be a potential option for targeted therapy in hematologic malignancies.

Notch in Leukemia

Notch is commonly activated in lymphoid malignancies through ligand-independent and ligand-dependent mechanisms. In T-cell acute lymphoblastic leukemia/lymphoma (T-ALL), ligand-independent activation predominates. Negative Regulatory Region (NRR) mutations trigger supraphysiological Notch1 activation by exposing the S2 site to proteolytic cleavage in the absence of ligand. Subsequently, cleavage at the S3 site generates the activated form of Notch, intracellular Notch (ICN). In contrast to T-ALL, in mature lymphoid neoplasms such as chronic lymphocytic leukemia (CLL), the S2 cleavage site is exposed through ligand-receptor interactions. Thus, agents that disrupt ligand-receptor interactions might be useful for treating these malignancies. Notch activation can be enhanced by mutations that delete the C-terminal proline (P), glutamic acid (E), serine (S), and threonine (T) (PEST) domain. These mutations do not activate the Notch pathway per se, but rather impair degradation of ICN. In this chapter, we review the mechanisms of Notch activation and the importance of Notch for the genesis and maintenance of lymphoid malignancies. Unfortunately, targeting the Notch pathway with pan-Notch inhibitors in clinical trials has proven challenging. These clinical trials have encountered dose-limiting on-target toxicities and primary resistance. Strategies to overcome these challenges have emerged from the identification and improved understanding of direct oncogenic Notch target genes. Other strategies have arisen from new insights into the "nuclear context" that selectively directs Notch functions in lymphoid cancers. This nuclear context is created by factors that co-bind ICN at cell-type specific transcriptional regulatory elements. Disrupting the functions of these proteins or inhibiting downstream oncogenic pathways might combat cancer without the intolerable side effects of pan-Notch inhibition.