Combinatorial efficacy of entospletinib and chemotherapy in patient-derived xenograft models of infant acute lymphoblastic leukemia

Integrative analysis of the ST6GALNAC family identifies GATA2-upregulated ST6GALNAC5 as an adverse prognostic biomarker promoting prostate cancer cell invasion

BACKGROUND

ST6GALNAC family members function as sialyltransferases and have been implicated in cancer progression. However, their aberrant expression levels, prognostic values and specific roles in metastatic prostate cancer (PCa) remain largely unclear.

METHODS

Two independent public datasets (TCGA-PRAD and GSE21032), containing 648 PCa samples in total, were employed to comprehensively examine the mRNA expression changes of ST6GALNAC family members in PCa, as well as their associations with clinicopathological parameters and prognosis. The dysregulation of ST6GALNAC5 was further validated in a mouse PCa model and human PCa samples from our cohort (n = 64) by immunohistochemistry (IHC). Gene Set Enrichment Analysis, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and drug sensitivity analyses were performed to enrich the biological processes most related to ST6GALNAC5. Sulforhodamine B, transwell, luciferase reporter and chromatin immunoprecipitation (ChIP) assays were used to examine the PCa cell proliferation, invasion and transcriptional regulation, respectively.

RESULTS

Systematical investigation of six ST6GALNAC family members in public datasets revealed that ST6GALNAC5 was the only gene consistently and significantly upregulated in metastatic PCa, and ST6GALNAC5 overexpression was also positively associated with Gleason score and predicted poor prognosis in PCa patients. IHC results showed that (1) ST6GALNAC5 protein expression was increased in prostatic intraepithelial neoplasia and further elevated in PCa from a PbCre;Pten^F/F mouse model; (2) overexpressed ST6GALNAC5 protein was confirmed in human PCa samples comparing with benign prostatic hyperplasia samples from our cohort (p < 0.001); (3) ST6GALNAC5 overexpression was significantly correlated with perineural invasion of PCa. Moreover, we first found transcription factor GATA2 positively and directly regulated ST6GALNAC5 expression at transcriptional level. ST6GALNAC5 overexpression could partially reverse GATA2-depletion-induced inhibition of PCa cell invasion. The GATA2-ST6GALNAC5 signature exhibited better prediction on the poor prognosis in PCa patients than GATA2 or ST6GALNAC5 alone.

CONCLUSIONS

Our results indicated that GATA2-upregulated ST6GALNAC5 might serve as an adverse prognostic biomarker promoting prostate cancer cell invasion.

Patient-derived xenograft models in cancer therapy: technologies and applications

Patient-derived xenograft (PDX) models, in which tumor tissues from patients are implanted into immunocompromised or humanized mice, have shown superiority in recapitulating the characteristics of cancer, such as the spatial structure of cancer and the intratumor heterogeneity of cancer. Moreover, PDX models retain the genomic features of patients across different stages, subtypes, and diversified treatment backgrounds. Optimized PDX engraftment procedures and modern technologies such as multi-omics and deep learning have enabled a more comprehensive depiction of the PDX molecular landscape and boosted the utilization of PDX models. These irreplaceable advantages make PDX models an ideal choice in cancer treatment studies, such as preclinical trials of novel drugs, validating novel drug combinations, screening drug-sensitive patients, and exploring drug resistance mechanisms. In this review, we gave an overview of the history of PDX models and the process of PDX model establishment. Subsequently, the review presents the strengths and weaknesses of PDX models and highlights the integration of novel technologies in PDX model research. Finally, we delineated the broad application of PDX models in chemotherapy, targeted therapy, immunotherapy, and other novel therapies.

Potent preclinical activity of FLT3-directed chimeric antigen receptor T-cell immunotherapy against FLT3- mutant acute myeloid leukemia and KMT2A-rearranged acute lymphoblastic leukemia

Chimeric antigen receptor (CAR) T-cell immunotherapies targeting CD19 or CD22 induce remissions in the majority of patients with relapsed/refractory B-cell acute lymphoblastic leukemia (ALL), although relapse due to target antigen loss or downregulation has emerged as a major clinical dilemma. Accordingly, great interest exists in developing CAR T cells directed against alternative leukemia cell surface antigens that may help to overcome immunotherapeutic resistance. The fms-like tyrosine kinase 3 receptor (FLT3) is constitutively activated via FLT3 mutation in acute myeloid leukemia (AML) or wild-type FLT3 overexpression in KMT2A (lysine-specific methyltransferase 2A)-rearranged ALL, which are associated with poor clinical outcomes in children and adults. We developed monovalent FLT3-targeted CAR T cells (FLT3CART) and bispecific CD19xFLT3CART and assessed their anti-leukemia activity in preclinical models of FLT3-mutant AML and KMT2A-rearranged infant ALL. We report robust in vitro FLT3CART-induced cytokine production and cytotoxicity against AML and ALL cell lines with minimal cross-reactivity against normal hematopoietic and non-hematopoietic tissues. We also observed potent in vivo inhibition of leukemia proliferation in xenograft models of both FLT3-mutant AML and KMT2A-rearranged ALL, including a post-tisagenlecleucel ALL-to-AML lineage switch patient-derived xenograft model pairing. We further demonstrate significant in vitro and in vivo activity of bispecific CD19xFLT3CART against KMT2Arearranged ALL and posit that this additional approach might also diminish potential antigen escape in these high-risk leukemias. Our preclinical data credential FLT3CART as a highly effective immunotherapeutic strategy for both FLT3- mutant AML and KMT2A-rearranged ALL which is poised for further investigation and clinical translation.

Evaluation of the HOXA9 and MEIS1 genes as a potential biomarker in adult acute myeloid leukemia

Background

Acute myeloid leukemia (AML) is a heterogeneous disorder encompassing a set of hematopoietic tumors that develop when the myeloid precursor cells undergo disproportionate clonal proliferation. Homeobox A 9 (HOXA9) is a pioneer transcription factor in AML pathogenesis along with its cofactor myeloid ecotropic integration site 1 (MEIS1). Our work aimed to evaluate the different expression levels of HOXA9 and MEIS1 genes and their diagnostic and prognostic significance in adult Egyptian patients with de novo AML. The study was carried out on 91 de novo AML Egyptian patients and 41 healthy individuals. Bone marrow samples were obtained from both patients and controls and then tested by reverse transcription-quantitative polymerase chain reaction to assess the mRNA expression in the studied genes.

Results

HOXA9 and MEIS1 gene expression levels were significantly elevated in AML patients compared to controls (p < 0.001). There was a statistically significant positive correlation between HOXA9 and MEIS1 gene expression in AML patients. However, there was no association between HOXA9 and MEIS1 gene expression levels and disease-free survival (DFS) and overall survival (OS) (p = 0.264 and 0.351, respectively).

Conclusion

HOXA9 and MEIS1 genes are highly expressed in Egyptian AML patients, suggesting their interesting pathogenic role in AML. They could be used as markers for the diagnosis of AML, but not for the disease prognosis.

Case Report: Rare IKZF1 Gene Fusions Identified in Neonate with Congenital KMT2A-Rearranged Acute Lymphoblastic Leukemia

Chromosomal rearrangements involving the KMT2A gene occur frequently in acute lymphoblastic leukaemia (ALL). KMT2A-rearranged ALL (KMT2Ar ALL) has poor long-term survival rates and is the most common ALL subtype in infants less than 1 year of age. KMT2Ar ALL frequently occurs with additional chromosomal abnormalities including disruption of the IKZF1 gene, usually by exon deletion. Typically, KMT2Ar ALL in infants is accompanied by a limited number of cooperative le-sions. Here we report a case of aggressive infant KMT2Ar ALL harbouring additional rare IKZF1 gene fusions. Comprehensive genomic and transcriptomic analyses were performed on sequential samples. This report highlights the genomic complexity of this particular disease and describes the novel gene fusions IKZF1::TUT1 and KDM2A::IKZF1.

Pharmacological management of cherubism: A systematic review

OBJECTIVE

The aim of this systematic review was to determine if there exists an efficacious drug treatment for cherubism, based on published studies.

METHODS

This systematic review included observational case studies reporting pharmacological management of cherubism. We developed specific search strategies for PubMed (including Medline), ScienceDirect, Web of Science. We evaluated the methodological quality of the included studies using criteria from the Joanna Briggs Institute's critical appraisal tools.

RESULTS

Among the 621 studies initially identified by our search script, 14 were selected for inclusion, of which five were classified as having a low risk of bias, four as having an unclear risk, and five a high risk. Overall, 18 cherubism patients were treated. The sample size in each case study ranged from one to three subjects. This review identified three types of drugs used for cherubism management: calcitonin, immunomodulators and anti-resorptive agents. However, the high heterogeneity in case reports and the lack of standardized outcomes precluded a definitive conclusion regarding the efficacy of any treatment for cherubism.

CONCLUSIONS

The present systematic review could not identify an effective treatment for cherubism due to the heterogeneity and limitations of the included studies. However, in response to these shortcomings, we devised a checklist of items that we recommend authors consider in order to standardize the reporting of cherubism cases and specifically when a treatment is given toward identification of an efficacious cherubism therapy.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022351044, identifier CRD42022351044.

Updates in infant acute lymphoblastic leukemia and the potential for targeted therapy

Outcomes for infants diagnosed under 1 year of age with KMT2A-rearranged acute lymphoblastic leukemia (ALL) have remained stagnant over the past 20 years. Successive treatment protocols have previously focused on intensification of conventional chemotherapy, but increased treatment-related toxicity and chemoresistance have led to a plateau in survival. We have now entered an era of immunotherapy with integration of agents, such as blinatumomab or chimeric antigen receptor T-cell therapy, into the standard chemotherapy backbone, showing significant promise for improving the dismal outcomes for this disease. There remains much optimism for the future as a wealth of preclinical studies have identified additional novel targeted agents, such as venetoclax or menin inhibitors, ready for incorporation into treatment, providing further ammunition to combat this aggressive disease. In contrast, infants with KMT2A-germline ALL have demonstrated excellent survival outcomes with current therapy, but there remains a high burden of treatment-related morbidity. Greater understanding of the underlying blast genetics for infants with KMT2A-germline ALL and incorporation of immunotherapeutic approaches may enable a reduction in the intensity of chemotherapy while maintaining the excellent outcomes.

Patient-derived intrafemoral orthotopic xenografts of peripheral blood or bone marrow from acute myeloid and acute lymphoblastic leukemia patients: clinical characterization, methodology, and validation

Acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) are malignant clonal diseases of the hematopoietic system with an unsatisfactory overall prognosis. The main obstacle is the increased resistance of AML and ALL cells to chemotherapy. The development and validation of new therapeutic strategies for acute leukemia require preclinical models that accurately recapitulate the genetic, pathological, and clinical features of acute leukemia. A patient-derived orthotopic xenograft (PDOX) model is established using surgical orthotopic implantation. They closely resemble human tumor progression and microenvironment and are more reliable translational research tools than subcutaneous-transplant models. In this study, we established PDOX models by direct intrafemoral injection of bone marrow and peripheral blood cells from AML and ALL patients, characterized their pathology, cytology, and genetics, and compared the model's characteristics and drug responsiveness with those of the corresponding patients.

Antitumor Effect of Brusatol in Acute Lymphoblastic Leukemia Models Is Triggered by Reactive Oxygen Species Accumulation

Acute lymphoblastic leukemia (ALL) is one of the most common hematological malignancies at pediatric ages and is characterized by different chromosomal rearrangements and genetic abnormalities involved in the differentiation and proliferation of lymphoid precursor cells. Brusatol is a quassinoid plant extract extensively studied due to its antineoplastic effect through global protein synthesis and nuclear factor erythroid 2-related factor-2 (NRF2) signaling inhibition. NRF2 is the main regulator of cellular antioxidant response and reactive oxygen species (ROS), which plays an important role in oxidative stress regulation. This study aimed to evaluate the effect of brusatol in in vitro models of ALL. KOPN-8 (B-ALL), CEM (T-ALL), and MOLT-4 (T-ALL) cell lines were incubated with increasing concentrations of brusatol, and the metabolic activity was evaluated using the resazurin assay. Flow cytometry was used to evaluate cell death, cell cycle, mitochondrial membrane potential (Δψmit), and to measure ROS and reduced glutathione (GSH) levels. Our results show that brusatol promoted a decrease in metabolic activity in ALL cell lines in a time-, dose-, and cell-line-dependent manner. Brusatol induced a cytostatic effect by cell cycle arrest in G0/G1 in all cell lines; however, cell death mediated by apoptosis was only observed in T-ALL cells. Brusatol leads to an oxidative stress imbalance by the increase in ROS levels, namely, superoxide anion. Redox imbalance and cellular apoptosis induced by brusatol are highly modulated by mitochondria disruption as a decrease in mitochondrial membrane potential is detected. These data suggest that brusatol might represent a new therapeutic approach for acute lymphoblastic leukemia, particularly for ALL T-cell lineage.

Genomic heterogeneity contributed to different prognosis between adult and pediatric acute lymphoblastic

The prognosis of acute lymphoblastic leukemia (ALL) in adults is inferior to that in children. Hence, ALL remains challenging to cure in the adult population. Aberrant genetic alterations have been observed in ALL, although the patterns of differential gene alterations in adult and pediatric ALL have not been comprehensively determined on a genome-wide scale. We investigated the biologic differences in genomic profiles between adults (n = 64) and children (n = 54) with ALL and relationship between genomic heterogeneity and prognosis. The 2 populations showed similar common mutation types but an increased prevalence of genetic alterations in adult ALL. The median numbers of gene mutations were 17 (range: 1-53) and 4.5 (range: 1-19) per sample in adult and pediatric ALL, respectively (p < 0.001). An increased number of gene mutations and age were significantly correlated (R²  = 0.5853, p < 0.001). We identified 122 and 53 driver genes in adult and pediatric ALL samples, respectively. IKZF1, IDH1, and TTN mutations were significantly enriched in adult patients with ALL. KRAS, ARID1A, and CREBBP mutations were significantly enriched in pediatric patients with ALL (p < 0.05). The incidence of relapse was 40.0% and 9.6% in adult and pediatric patients with ALL, respectively (p = 0.003). The overall survival and relapse-free survival of adult patients with ALL were poorer than those of pediatric patients with ALL (p = 0.002 and p < 0.001, respectively). This genomic landscape enhances the understanding of the biologic differences in ALL between the 2 populations and provides insight for developing therapeutic approaches.

Activated interleukin-7 receptor signaling drives B-cell acute lymphoblastic leukemia in mice

Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is a high-risk subtype of B-ALL often associated with genetic variants that alter cytokine receptor signaling, including mutations in the interleukin-7 receptor (IL7R). To investigate whether IL7R variants are leukemia-initiating, we built mouse models expressing activated Il7r (aIL7R). B-cell intrinsic aIL7R mice developed spontaneous B-ALL, demonstrating sufficiency of Il7r activating mutations in leukemogenesis. Concomitant introduction of a knock-out allele in the associated adapter protein Lnk (encoded by Sh2b3) or a dominant-negative variant of the transcription factor Ikaros (Ikzf1) increased disease penetrance. The resulting murine leukemias displayed monoclonality and recurrent somatic Kras mutations and efficiently engrafted into immunocompetent mice. Phosphoproteomic analyses of aIL7R leukemic cells revealed constitutive Stat5 signaling and B cell receptor (BCR)-like signaling despite the absence of surface pre-BCR. Finally, in vitro treatment of aIL7R leukemic B-cells with Jak, mTOR, or Syk inhibitors blocked growth, confirming that each pathway is active in this mouse model of IL7R-driven B-ALL.

MEIS1 in Hematopoiesis and Cancer. How MEIS1-PBX Interaction Can Be Used in Therapy

Recently MEIS1 emerged as a major determinant of the MLL-r leukemic phenotype. The latest and most efficient drugs effectively decrease the levels of MEIS1 in cancer cells. Together with an overview of the latest drugs developed to target MEIS1 in MLL-r leukemia, we review, in detail, the role of MEIS1 in embryonic and adult hematopoiesis and suggest how a more profound knowledge of MEIS1 biochemistry can be used to design potent and effective drugs against MLL-r leukemia. In addition, we present data showing that the interaction between MEIS1 and PBX1 can be blocked efficiently and might represent a new avenue in anti-MLL-r and anti-leukemic therapy.

Pediatric Mixed-Phenotype Acute Leukemia: What's New?

Simple Summary

Pediatric mixed-phenotype leukemia is a rare form of blood cancer in children. In this review, we cover both the evolution of treatment over the past several years and outline new emerging concepts in this disease.

Abstract

Mixed-phenotype acute leukemias (MPAL) are rare in children and often lack consensus on optimal management. This review examines the current controversies and emerging paradigms in the management of pediatric MPAL. We examine risk stratification, outcomes of recent retrospective and prospective collaborative trials, and the role of transplantation and precision genomics, and outline emerging targets and concepts in this rare entity.

Oncogene-independent BCR-like signaling adaptation confers drug resistance in Ph-like ALL

Children and adults with Philadelphia chromosome-like B cell acute lymphoblastic leukemia (Ph-like B-ALL) experience high relapse rates despite best-available conventional chemotherapy. Ph-like ALL is driven by genetic alterations that activate constitutive cytokine receptor and kinase signaling, and early-phase trials are investigating the potential of the addition of tyrosine kinase inhibitors (TKIs) to chemotherapy to improve clinical outcomes. However, preclinical studies have shown that JAK or PI3K pathway inhibition is insufficient to eradicate the most common cytokine receptor-like factor 2-rearranged (CRLF2-rearranged) Ph-like ALL subset. We thus sought to define additional essential signaling pathways required in Ph-like leukemogenesis for improved therapeutic targeting. Herein, we describe an adaptive signaling plasticity of CRLF2-rearranged Ph-like ALL following selective TKI pressure, which occurs in the absence of genetic mutations. Interestingly, we observed that Ph-like ALL cells have activated SRC, ERK, and PI3K signaling consistent with activated B cell receptor (BCR) signaling, although they do not express cell surface μ-heavy chain (μHC). Combinatorial targeting of JAK/STAT, PI3K, and "BCR-like" signaling with multiple TKIs and/or dexamethasone prevented this signaling plasticity and induced complete cell death, demonstrating a more optimal and clinically pragmatic therapeutic strategy for CRLF2-rearranged Ph-like ALL.