WEE1 inhibition induces glutamine addiction in T-cell acute lymphoblastic leukemia

Targeting the DNA damage response in hematological malignancies

Deregulation of the DNA damage response (DDR) plays a critical role in the pathogenesis and progression of many cancers. The dependency of certain cancers on DDR pathways has enabled exploitation of such through synthetically lethal relationships e.g., Poly ADP-Ribose Polymerase (PARP) inhibitors for BRCA deficient ovarian cancers. Though lagging behind that of solid cancers, DDR inhibitors (DDRi) are being clinically developed for haematological cancers. Furthermore, a high proliferative index characterize many such cancers, suggesting a rationale for combinatorial strategies targeting DDR and replicative stress. In this review, we summarize pre-clinical and clinical data on DDR inhibition in haematological malignancies and highlight distinct haematological cancer subtypes with activity of DDR agents as single agents or in combination with chemotherapeutics and targeted agents. We aim to provide a framework to guide the design of future clinical trials involving haematological cancers for this important class of drugs.

XPO1 Enables Adaptive Regulation of mRNA Export Required for Genotoxic Stress Tolerance in Cancer Cells

Exportin-1 (XPO1), the main soluble nuclear export receptor in eukaryotic cells, is frequently overexpressed in diffuse large B-cell lymphoma (DLBCL). A selective XPO1 inhibitor, selinexor, received approval as single agent for relapsed or refractory (R/R) DLBCL. Elucidating the mechanisms by which XPO1 overexpression supports cancer cells could facilitate further clinical development of XPO1 inhibitors. We uncovered here that XPO1 overexpression increases tolerance to genotoxic stress, leading to a poor response to chemoimmunotherapy. Upon DNA damage induced by MYC expression or exogenous compounds, XPO1 bound and exported EIF4E and THOC4 carrying DNA damage repair mRNAs, thereby increasing synthesis of DNA damage repair proteins under conditions of increased turnover. Consequently, XPO1 inhibition decreased the capacity of lymphoma cells to repair DNA damage and ultimately resulted in increased cytotoxicity. In a phase I clinical trial conducted in R/R DLBCL, the combination of selinexor with second-line chemoimmunotherapy was tolerated with early indication of efficacy. Overall, this study reveals that XPO1 overexpression plays a critical role in the increased tolerance of cancer cells to DNA damage while providing new insights to optimize the clinical development of XPO1 inhibitors.

SIGNIFICANCE

XPO1 regulates the dynamic ribonucleoprotein nuclear export in response to genotoxic stress to support tolerance and can be targeted to enhance the sensitivity of cancer cells to endogenous and exogenous DNA damage. See related commentary by Knittel and Reinhardt, p. 3.

Identification of USP29 as a key regulator of nucleotide biosynthesis in neuroblastoma through integrative analysis of multi-omics data

Cancer cells show enhanced nucleotide biosynthesis, which is essential for their unlimited proliferation, but the underlying mechanisms are not entirely clear. Ubiquitin specific peptidase 29 (USP29) was reported to sustain neuroblastoma progression by promoting glycolysis and glutamine catabolism; however, its potential role in regulating nucleotide biosynthesis in tumor cells remains unknown. In this study, we depleted endogenous USP29 in MYCN-amplified neuroblastoma SK-N-BE2 cells by sgRNAs and conducted metabolomic analysis in cells with or without USP29 depletion, we found that USP29 deficiency caused a disorder of intermediates involved in glycolysis and nucleotide biosynthesis. De novo nucleotide biosynthesis was analyzed using 13C6 glucose as a tracer under normoxia and hypoxia. The results indicated that USP29-depleted cells showed inhibition of nucleotide anabolic intermediates derived from glucose, and this inhibition was more significant under hypoxic conditions. Analysis of RNA sequencing data in SK-N-BE2 cells demonstrated that USP29 promoted the gene expression of metabolic enzymes involved in nucleotide anabolism, probably by regulating MYC and E2F downstream pathways. These findings indicated that USP29 is a key regulator of nucleotide biosynthesis in tumor cells.

Synergistic interactions of cytarabine-adavosertib in leukemic cell lines proliferation and metabolomic endpoints

Drug synergy allows reduced dosing, side effects and tolerance. Optimization of drug synergy chemotherapy is fundamental in acute lymphocytic leukemia and other cancers. This study aimed to analyze the pharmacodynamic synergy between the anti-metabolite cytarabine and WEE1 inhibitor adavosertib on acute leukemia cell lines CCRF-CEM and Jurkat. In both cell lines analysis of concentration-inhibition curves of adavosertib-cytarabine combinations and synergy matrixes supported mutually synergistic drug interactions. Overall mean ( ± SD) synergy scores were higher in Jurkat than CCRF-CEM: Jurkat, ZIP 22.51 ± 1.1, Bliss 22.49 ± 1.1, HSA 23.44 ± 1.0, Loewe 14.16 ± 1.2; and, CCRF-CEM, ZIP 9.17 ± 1.9, Bliss 8.13 ± 2.1, HSA 11.48 ± 1.9 and Loewe 4.99 ± 1.8. Jurkat also surpassed CCRF-CEM in high-degree synergistic adavosertib-cytarabine interactions with mean across-models synergy values of ∼89.1% ± 2.9 for 63 nM cytarabine-97 nM adavosertib (91.4% inhibition synergy barometer). Combination sensitivity scores scatter plots confirmed combination's synergy efficacy. This combined approach permitted identification and prioritization of 63 nM cytarabine-97 nM adavosertib for multiple endpoints analysis. This combination did not affect PBMC viability, while exhibiting Jurkat selective synergy. Immunoblots also revealed Jurkat selective synergistically increased γH2AX phosphorylation, while CDC2 phosphorylation effects were attributed to adavosertib's WEE1 inhibition. In conclusion, the high synergistic efficacy combination of cytarabine (63 nM) and adavosertib (97 nM) was associated with remarkable alterations in metabolites related to the Krebs cycle in Jurkat. The metabolic pathways and processes are related to gluconeogenesis, amino acids, nucleotides, glutathione, electron transport and Warburg effect. All above relate to cell survival, apoptosis, and cancer progression. Our findings could pave the way for novel biomarkers in treatment, diagnosis, and prognosis of leukemia and other cancers.

Development of an in vitro genotoxicity assay to detect retroviral vector-induced lymphoid insertional mutants

Safety assessment in retroviral vector-mediated gene therapy remains challenging. In clinical trials for different blood and immune disorders, insertional mutagenesis led to myeloid and lymphoid leukemia. We previously developed the In Vitro Immortalization Assay (IVIM) and Surrogate Assay for Genotoxicity Assessment (SAGA) for pre-clinical genotoxicity prediction of integrating vectors. Murine hematopoietic stem and progenitor cells (mHSPCs) transduced with mutagenic vectors acquire a proliferation advantage under limiting dilution (IVIM) and activate stem cell- and cancer-related transcriptional programs (SAGA). However, both assays present an intrinsic myeloid bias due to culture conditions. To detect lymphoid mutants, we differentiated mHSPCs to mature T cells and analyzed their phenotype, insertion site pattern, and gene expression changes after transduction with retroviral vectors. Mutagenic vectors induced a block in differentiation at an early progenitor stage (double-negative 2) compared to fully differentiated untransduced mock cultures. Arrested samples harbored high-risk insertions close to Lmo2, frequently observed in clinical trials with severe adverse events. Lymphoid insertional mutants displayed a unique gene expression signature identified by SAGA. The gene expression-based highly sensitive molecular readout will broaden our understanding of vector-induced oncogenicity and help in pre-clinical prediction of retroviral genotoxicity.

Optimization of L-glutaminase production by Monascus ruber URM 8542 isolated from ice cream industrial effluent

L-glutaminase is a hydrolytic enzyme with wide biotechnological applications. Mostly, these enzymes are employed in the feed industry for flavor enhancement and acrylamide mitigation. Also, L-glutaminase may have antiviral and antineoplastic effects making it a good choice for pharmaceutical applications. In this study, the strain Monascus ruber URM 8542 was identified through classical and molecular taxonomy using partial sequencing of β-tubulin and calmodulin genes. Subsequently, the optimal culture conditions were evaluated by submerged fermentation (L-glutamine 10 g.L- 1) for L-glutaminase excretion. The isolate was identified as M. ruber URM 8542 which showed significant extracellular enzyme production with a yield of 11.4 times in relation to the specific activity of intracellular L-glutaminase. Regarding the optimization experiments, several factors such as L-glutamine concentration, temperature, and pH were compared using a full factorial design (23). The concentrations greater than 1% proved to be significantly better for glutaminase production (R2 = 0.9077). Additionally, the L-glutaminase was optimally active at pH 7.0 and 30 ºC. The L-glutaminase was remarkably stable across an alkaline pH range (7.0-8.0) and had a thermal stability ranging from 30 ºC to 60 ºC for 1 h. Taken together, these findings suggest that the L-glutaminase produced by M. ruber is a promising candidate for pharmacological application, although further studies need to be performed. To the best of our knowledge, this is the first report of L-glutaminase production by Monascus ruber.

USP1 promotes the aerobic glycolysis and progression of T-cell acute lymphoblastic leukemia via PLK1/LDHA axis

The effect of aerobic glycolysis remains elusive in pediatric T-cell acute lymphoblastic leukemia (T-ALL). Increasing evidence has revealed that dysregulation of deubiquitination is involved in glycolysis, by targeting glycolytic rate-limiting enzymes. Here, we demonstrated that upregulated deubiquitinase ubiquitin-specific peptidase 1 (USP1) expression correlated with poor prognosis in pediatric primary T-ALL samples. USP1 depletion abolished cellular proliferation and attenuated glycolytic metabolism. In vivo experiments showed that USP1 suppression decreased leukemia progression in nude mice. Inhibition of USP1 caused a decrease in both mRNA and protein levels in lactate dehydrogenase A (LDHA), a critical glycolytic enzyme. Moreover, USP1 interacted with and deubiquitinated polo-like kinase 1 (PLK1), a critical regulator of glycolysis. Overexpression of USP1 with upregulated PLK1 was observed in most samples of patients with T-ALL. In addition, PLK1 inhibition reduced LDHA expression and abrogated the USP1-mediated increase of cell proliferation and lactate level. Ectopic expression of LDHA can rescue the suppressive effect of USP1 silencing on cell growth and lactate production. Pharmacological inhibition of USP1 by ML323 exhibited cell cytotoxicity in human T-ALL cells. Taken together, our results demonstrated that USP1 may be a promising therapeutic target in pediatric T-ALL.

Glutamine Metabolism Underlies the Functional Similarity of T Cells between Nile Tilapia and Tetrapod

As the lowest organisms possessing T cells, fish are instrumental for understanding T cell evolution and immune defense in early vertebrates. This study established in Nile tilapia models suggests that T cells play a critical role in resisting Edwardsiella piscicida infection via cytotoxicity and are essential for IgM⁺ B cell response. CD3 and CD28 monoclonal antibody crosslinking reveals that full activation of tilapia T cells requires the first and secondary signals, while Ca²⁺ -NFAT, MAPK/ERK, NF-κB, and mTORC1 pathways and IgM⁺ B cells collectively regulate T cell activation. Thus, despite the large evolutionary distance, tilapia and mammals such as mice and humans exhibit similar T cell functions. Furthermore, it is speculated that transcriptional networks and metabolic reprogramming, especially c-Myc-mediated glutamine metabolism triggered by mTORC1 and MAPK/ERK pathways, underlie the functional similarity of T cells between tilapia and mammals. Notably, tilapia, frogs, chickens, and mice utilize the same mechanisms to facilitate glutaminolysis-regulated T cell responses, and restoration of the glutaminolysis pathway using tilapia components rescues the immunodeficiency of human Jurkat T cells. Thus, this study provides a comprehensive picture of T cell immunity in tilapia, sheds novel perspectives for understanding T cell evolution, and offers potential avenues for intervening in human immunodeficiency.

MiR-652-5p elevated glycolysis level by targeting TIGAR in T-cell acute lymphoblastic leukemia

The effect of glycolysis remains largely elusive in acute T lymphoblastic leukemia (T-ALL). Increasing evidence has indicated that the dysregulation of miRNAs is involved in glycolysis, by targeting the genes coding glycolysis rate-limiting enzymes. In our previous studies, we found that overexpression of the ARRB1-derived miR-223 sponge repressed T-ALL progress and reduced the expression of miR-652-5p. However, little is known about miR-652-5p on T-ALL. Here, we showed that impaired miR-652-5p expression inhibited growth, promoted apoptosis of T-ALL cells in vitro and prolonged overall survival (OS) in vivo. Based on the GO enrichment of miR-652-5p target genes, we uncovered that impaired miR-652-5p decreased glycolysis, including reduced the lactate, pyruvate, ATP level and the total extracellular acidification rate (ECAR), elevated oxygen consumption rate (OCR) in T-ALL cell lines. Mechanically, miR-652-5p targeted the 3ʹUTR of Tigar mRNA and inhibited its expression. Furthermore, the alteration of glycosis level was attributed to Tigar overexpression, consistent with the effect of impaired miR-652-5p. Additionally, Tigar suppressed the expression of PFKFB3, a glycolysis rate-limiting enzyme, in vivo and in vitro. Taken together, our results demonstrate that impaired miR-652-5p/Tigar axis could repress glycolysis, thus to slow growth of T-ALL cells, which support miR-652-5p as a novel potential drug target for T-ALL therapeutics.

The LncRNA DUXAP10 Could Function as a Promising Oncogene in Human Cancer

Cancer is one of the most prevalent and deadliest diseases globally, with an increasing morbidity of approximately 14 million new cancer cases per year. Identifying novel diagnostic and prognostic biomarkers for cancers is important for developing cancer therapeutic strategies and lowering mortality rates. Long noncoding RNAs (lncRNAs) represent a group of noncoding RNAs of more than 200 nucleotides that have been shown to participate in the development of human cancers. The novel lncRNA DUXAP10 was newly reported to be abnormally overexpressed in several cancers and positively correlated with poor clinical characteristics of cancer patients. Multiple studies have found that DUXAP10 widely regulates vital biological functions related to the development and progression of cancers, including cell proliferation, apoptosis, invasion, migration, and stemness, through different molecular mechanisms. The aim of this review was to recapitulate current findings regarding the roles of DUXAP10 in cancers and evaluate the potential of DUXAP10 as a novel biomarker for cancer diagnosis, treatment, and prognostic assessment.

Insights on Metabolic Reprogramming and Its Therapeutic Potential in Acute Leukemia

Acute leukemias, classified as acute myeloid leukemia and acute lymphoblastic leukemia, represent the most prevalent hematologic tumors in adolescent and young adults. In recent years, new challenges have emerged in order to improve the clinical effectiveness of therapies already in use and reduce their side effects. In particular, in this scenario, metabolic reprogramming plays a key role in tumorigenesis and prognosis, and it contributes to the treatment outcome of acute leukemia. This review summarizes the latest findings regarding the most relevant metabolic pathways contributing to the continuous growth, redox homeostasis, and drug resistance of leukemia cells. We describe the main metabolic deregulations in acute leukemia and evidence vulnerabilities that could be exploited for targeted therapy.

Pharmacological Inhibition of WEE1 Potentiates the Antitumoral Effect of the dl922-947 Oncolytic Virus in Malignant Mesothelioma Cell Lines

Malignant mesothelioma (MM) is a very aggressive asbestos-related cancer, for which no therapy proves to be effective. We have recently shown that the oncolytic adenovirus dl922-947 had antitumor effects in MM cell lines and murine xenografts. Previous studies demonstrated that dl922-947-induced host cell cycle checkpoint deregulation and consequent DNA lesions associated with the virus efficacy. However, the cellular DNA damage response (DDR) can counteract this virus action. Therefore, we assessed whether AZD1775, an inhibitor of the G2/M DNA damage checkpoint kinase WEE1, could enhance MM cell sensitivity to dl922-947. Through cell viability assays, we found that AZD1775 synergized with dl922-947 selectively in MM cell lines and increased dl922-947-induced cell death, which showed hallmarks of apoptosis (annexinV-positivity, caspase-dependency, BCL-XL decrease, chromatin condensation). Predictably, dl922-947 and/or AZD1775 activated the DDR, as indicated by increased levels of three main DDR players: phosphorylated histone H2AX (γ-H2AX), phospho-replication protein A (RPA)32, phospho-checkpoint kinase 1 (CHK1). Dl922-947 also increased inactive Tyr-15-phosphorylated cyclin-dependent kinase 1 (CDK1), a key WEE1 substrate, which is indicative of G2/M checkpoint activation. This increase in phospho-CDK1 was effectively suppressed by AZD1775, thus suggesting that this compound could, indeed, abrogate the dl922-947-induced DNA damage checkpoint in MM cells. Overall, our data suggest that the dl922-947-AZD1775 combination could be a feasible strategy against MM.