Novel NPM1 exon 5 mutations and gene fusions leading to aberrant cytoplasmic nucleophosmin in AML

Recent advances in AML with mutated NPM1

Nucleophosmin 1 (NPM1) mutation is one of the most prevalent genetic mutations in adult acute myeloid leukemia (AML) and is particularly predominant in AML with a normal karyotype. NPM1 is a chaperone protein that plays various roles in several cellular processes. Wild-type NPM1 is normally localized to the nucleus, whereas mutant NPM1 proteins exhibit altered cytoplasmic localization. Clinically, AML with mutated NPM1 without FLT3-ITD is associated with a higher complete remission rate and improved overall survival. AML with mutated NPM1 is categorized as a distinct genetic entity in the World Health Organization classification of hematopoietic malignancies due to its unique clinical and biological features. However, the precise roles of NPM1 in normal hematopoiesis and in AML development remain unclear. Recent studies have revealed various clinical applications of NPM1 mutations in AML treatment, particularly in measurable residual disease analyses that target mutant NPM1 transcripts and in potential therapeutic applications of menin inhibitors and XPO-1 inhibitors for AML with mutated NPM1. Thus, NPM1 mutation is highly significant in AML classification, prognosis, response assessment, and molecular targeted therapies. Here, we review recent progress in clinical and biological aspects of AML with mutated NPM1 including molecular targeted therapy.

Common Driver Mutations in AML: Biological Impact, Clinical Considerations, and Treatment Strategies

Next-generation sequencing of samples from patients with acute myeloid leukemia (AML) has revealed several driver gene mutations in adult AML. However, unlike other cancers, AML is defined by relatively few mutations per patient, with a median of 4-5 depending on subtype. In this review, we will discuss the most common driver genes found in patients with AML and focus on the most clinically relevant ones that impact treatment strategies. The most common driver gene mutations in AML occur in NPM1 and FLT3, accounting for ~30% each. There are now targeted therapies being tested or already approved for these driver genes. Menin inhibitors, a novel targeted therapy that blocks the function of the menin protein, are in clinical trials for NPM1 driver gene mutant AML after relapse. A number of FLT3 inhibitors are now approved for FLT3 driver gene mutant AML in combination with chemotherapy in the frontline and also as single agent in relapse. Although mutations in IDH1/2 and TP53 only occur in around 10-20% of patients with AML each, they can affect the treatment strategy due to their association with prognosis and availability of targeted agents. While the impact of other driver gene mutations in AML is recognized, there is a lack of data on the actionable impact of those mutations.

Optical genome mapping improves the accuracy of classification, risk stratification, and personalized treatment strategies for patients with acute myeloid leukemia

Cytogenomic characterization is crucial for the classification and risk stratification of acute myeloid leukemia (AML), thereby facilitating therapeutic decision-making. We examined the clinical utility of optical genome mapping (OGM) in 159 AML patients (103 newly diagnosed and 56 refractory/relapsed), all of whom also underwent chromosomal banding analysis (CBA), fluorescence in situ hybridization, and targeted next-generation sequencing. OGM detected nearly all clinically relevant cytogenetic abnormalities that SCG identified with >99% sensitivity, provided the clonal burden was above 20%. OGM identified additional cytogenomic aberrations and/or provided information on fusion genes in 77 (48%) patients, including eight patients with normal karyotypes and four with failed karyotyping. The most common additional alterations identified by OGM included chromoanagenesis (n = 23), KMT2A partial tandem duplication (n = 11), rearrangements involving MECOM (n = 7), NUP98 (n = 2), KMT2A (n = 2), JAK2 (n = 2), and other gene fusions in 17 patients, with 10 showing novel fusion gene partners. OGM also pinpointed fusion genes in 17 (11%) patients where chromosomal rearrangements were concurrently detected by OGM and CBA. Overall, 24 (15%) aberrations were identified exclusively by OGM and had the potential to alter AML classification, risk stratification, and/or clinical trial eligibility. OGM emerges as a powerful tool for identifying fusion genes and detecting subtle or cryptic cytogenomic aberrations that may otherwise remain undetectable by CBA.

Diagnostic utility of immunohistochemistry in detection of NPM1 mutations in acute myeloid leukemia with a patchy distribution

Nucleophosmin 1 (NPM1) mutations occur in approximately one-third cases of adult de novo acute myeloid leukemia (AML). Identification of NPM1 mutations is important for classification, risk stratification, tailored therapy, and monitoring minimal residual disease. Mutational analysis is widely used for detecting NPM1 mutations. Immunochemistry assessing abnormal cytoplasmic localization of NPM1 protein has been used as a surrogate marker for NPM1 mutations. We present a case of AML with mutated NPM1 that was missed by sequencing analysis but detected by immunohistochemistry. This case highlights the value of immunohistochemistry in identifying NPM1 mutations in a subset of AML cases.

Mapping AML heterogeneity - multi-cohort transcriptomic analysis identifies novel clusters and divergent ex-vivo drug responses

Subtyping of acute myeloid leukaemia (AML) is predominantly based on recurrent genetic abnormalities, but recent literature indicates that transcriptomic phenotyping holds immense potential to further refine AML classification. Here we integrated five AML transcriptomic datasets with corresponding genetic information to provide an overview (n = 1224) of the transcriptomic AML landscape. Consensus clustering identified 17 robust patient clusters which improved identification of CEBPA-mutated patients with favourable outcomes, and uncovered transcriptomic subtypes for KMT2A rearrangements (2), NPM1 mutations (5), and AML with myelodysplasia-related changes (AML-MRC) (5). Transcriptomic subtypes of KMT2A, NPM1 and AML-MRC showed distinct mutational profiles, cell type differentiation arrests and immune properties, suggesting differences in underlying disease biology. Moreover, our transcriptomic clusters show differences in ex-vivo drug responses, even when corrected for differentiation arrest and superiorly capture differences in drug response compared to genetic classification. In conclusion, our findings underscore the importance of transcriptomics in AML subtyping and offer a basis for future research and personalised treatment strategies. Our transcriptomic compendium is publicly available and we supply an R package to project clusters to new transcriptomic studies.

Panel-based RNA fusion sequencing improves diagnostics of pediatric acute myeloid leukemia

New methods like panel-based RNA fusion sequencing (RNA-FS) promise improved diagnostics in various malignancies. We here analyzed the impact of RNA-FS on the initial diagnostics of 241 cases with pediatric acute myeloid leukemia (AML). We show that, compared to classical cytogenetics (CCG), RNA-FS reliably detected risk-relevant fusion genes in pediatric AML. In addition, RNA-FS strongly improved the detection of cryptic fusion genes like NUP98::NSD1, KMT2A::MLLT10 and CBFA2T3::GLIS2 and thereby resulted in an improved risk stratification in 25 patients (10.4%). Validation of additionally detected non-risk-relevant high confidence fusion calls identified PIM3::BRD1, C22orf34::BRD1, PSPC1::ZMYM2 and ARHGAP26::NR3C1 as common genetic variants and MYB::GATA1 as recurrent aberration, which we here describe in AML subtypes M0 and M7 for the first time. However, it failed to detect rare cytogenetically confirmed fusion events like MNX1::ETV6 and other chromosome 12p-abnormalities. As add-on benefit, the proportion of patients for whom measurable residual disease (MRD) monitoring became possible was increased by RNA-FS from 44.4 to 75.5% as the information on the fusion transcripts' sequence allowed the design of new MRD assays.

A new genomic framework to categorize pediatric acute myeloid leukemia

Recent studies on pediatric acute myeloid leukemia (pAML) have revealed pediatric-specific driver alterations, many of which are underrepresented in the current classification schemas. To comprehensively define the genomic landscape of pAML, we systematically categorized 887 pAML into 23 mutually distinct molecular categories, including new major entities such as UBTF or BCL11B, covering 91.4% of the cohort. These molecular categories were associated with unique expression profiles and mutational patterns. For instance, molecular categories characterized by specific HOXA or HOXB expression signatures showed distinct mutation patterns of RAS pathway genes, FLT3 or WT1, suggesting shared biological mechanisms. We show that molecular categories were strongly associated with clinical outcomes using two independent cohorts, leading to the establishment of a new prognostic framework for pAML based on these updated molecular categories and minimal residual disease. Together, this comprehensive diagnostic and prognostic framework forms the basis for future classification of pAML and treatment strategies.

Criteria for Diagnosis and Molecular Monitoring of NPM1-Mutated AML

NPM1-mutated acute myeloid leukemia (AML) represents the largest molecular subgroup of adult AML. NPM1-mutated AML is recognizable by molecular techniques and immunohistochemistry, which, when combined, can solve difficult diagnostic problems (including identification of myeloid sarcoma and NPM1 mutations outside exon 12). According to updated 2022 European LeukemiaNet (ELN) guidelines, determining the mutational status of NPM1 (and FLT3) is a mandatory step for the genetic-based risk stratification of AML. Monitoring of measurable residual disease (MRD) by qRT-PCR, combined with ELN risk stratification, can guide therapeutic decisions at the post-remission stage. Here, we review the criteria for appropriate diagnosis and molecular monitoring of NPM1-mutated AML.

SIGNIFICANCE

NPM1-mutated AML represents a distinct entity in the 2022 International Consensus Classification and 5th edition of World Health Organization classifications of myeloid neoplasms. The correct diagnosis of NPM1-mutated AML and its distinction from other AML entities is extremely important because it has clinical implications for the management of AML patients, such as genetic-based risk stratification according to 2022 ELN. Monitoring of MRD by qRT-PCR, combined with ELN risk stratification, can guide therapeutic decisions at the post-remission stage, e.g., whether or not to perform allogeneic hematopoietic stem cell transplantation.

NPM3 as an Unfavorable Prognostic Biomarker Involved in Oncogenic Pathways of Lung Adenocarcinoma via MYC Translational Activation

BACKGROUND

The nucleoplasmin/nucleophosmin (NPM) family was previously regarded as a critical regulator during disease development, and its mediation in carcinogenesis has achieved intensive attention recently. However, the clinical importance and functional mechanism of NPM3 in lung adenocarcinoma (LUAD) have not been reported yet.

OBJECTIVE

This study aimed to investigate the role and clinical significance of NPM3 in the development and progression of LUAD, including the underlying mechanisms.

METHODS

The expression of NPM3 in pan-cancer was analyzed via GEPIA. The effect of NPM3 on prognosis was analyzed by the Kaplan-Meier plotter and the PrognoScan database. In vitro, cell transfection, RT-qPCR, CCK-8 assay, and wound healing assay were employed to examine the role of NPM3 in A549 and H1299 cells. Gene set enrichment analysis (GSEA) was performed using the R software package to analyze the tumor hallmark pathway and KEGG pathway of NPM3. The transcription factors of NPM3 were predicted based on the ChIP-Atlas database. Dual-luciferase reporter assay was applied to verify the transcriptional regulatory factor of the NPM3 promoter region.

RESULTS

The NPM3 expression was found to be markedly higher in the LUAD tumor group than the normal group and to be positively correlated with poor prognosis, tumor stages, and radiation therapy. In vitro, the knockdown of NPM3 greatly inhibited the proliferation and migration of A549 and H1299 cells. Mechanistically, GSEA predicted that NPM3 activated the oncogenic pathways. Further, the NPM3 expression was found to be positively correlated with cell cycle, DNA replication, G2M checkpoint, HYPOXIA, MTORC1 signaling, glycolysis, and MYC targets. Besides, MYC targeted the promoter region of NPM3 and contributed to the enhanced expression of NPM3 in LUAD.

CONCLUSION

The overexpression of NPM3 is an unfavorable prognostic biomarker participating in oncogenic pathways of LUAD via MYC translational activation and it contributes to tumor progression. Thus, NPM3 could be a novel target for LUAD therapy.

Transcriptome analysis reveals a lncRNA-miRNA-mRNA regulatory network in OsRpp30-mediated disease resistance in rice

BACKGROUND

Long non-coding RNAs (lncRNAs) play critical roles in various biological processes in plants. Extensive studies utilizing high-throughput RNA sequencing have revealed that many lncRNAs are involved in plant disease resistance. Oryza sativa RNase P protein 30 (OsRpp30) has been identified as a positive regulator of rice immunity against fungal and bacterial pathogens. Nevertheless, the specific functions of lncRNAs in relation to OsRpp30-mediated disease resistance in rice remain elusive.

RESULTS

We conducted a comprehensive analysis of lncRNAs, miRNAs, and mRNAs expression patterns in wild type (WT), OsRpp30 overexpression (OsRpp30-OE), and OsRpp30 knockout (OsRpp30-KO) rice plants. In total, we identified 91 differentially expressed lncRNAs (DElncRNAs), 1671 differentially expressed mRNAs (DEmRNAs), and 41 differentially expressed miRNAs (DEmiRNAs) across the different rice lines. To gain further insights, we investigated the interaction between DElncRNAs and DEmRNAs, leading to the discovery of 10 trans- and 27 cis-targeting pairs specific to the OsRpp30-OE and OsRpp30-KO samples. In addition, we constructed a competing endogenous RNA (ceRNA) network comprising differentially expressed lncRNAs, miRNAs, and mRNAs to elucidate their intricate interplay in rice disease resistance. The ceRNA network analysis uncovered a set of gene targets regulated by lncRNAs and miRNAs, which were found to be involved in pathogen recognition, hormone pathways, transcription factor activation, and other biological processes related to plant immunity.

CONCLUSIONS

Our study provides a comprehensive expression profiling of lncRNAs, miRNAs, and mRNAs in a collection of defense mutants in rice. To decipher the putative functional significance of lncRNAs, we constructed trans- and cis-targeting networks involving differentially expressed lncRNAs and mRNAs, as well as a ceRNA network incorporating differentially expressed lncRNAs, miRNAs, and mRNAs. Together, the findings from this study provide compelling evidence supporting the pivotal roles of lncRNAs in OsRpp30-mediated disease resistance in rice.

Identification of a novel NPM1 mutation in acute myeloid leukemia

Nucleophosmin (NPM1) is a widely expressed nucleocytoplasmic shuttling protein with prominent nucleolar localization. It is estimated that 25-35% of adult patients with acute myeloid leukemia (AML) carry NPM1 mutations. The classic NPM1 type A mutation occurs in exon 12, which accounts for 75-80% of adult patients with NPM1-mutated AML. It produces an additional leucine and valine-rich nuclear export signal (NES) at the C-terminus, and causes aberrant cytoplasmic dislocation of NPM1 protein. Notably, emerging evidence indicates that besides the classic type A mutation, rare mutants occurring in other exons may also lead to the imbalance of the nucleocytoplasmic shuttle of NPM1. Identification of novel non-type A mutants is crucial for the diagnosis, prognosis, risk stratification and disease monitoring of potential target populations. Here we reported a novel NPM1 mutation in exon 5 identified from a de novo AML patient. Similar to the classic type A mutation, the exon 5 mutation had the NPM1 mutant bound to exportin-1 and directed the mutant into the cytoplasm by generating an additional NES sequence, resulting in aberrant cytoplasmic dislocation of NPM1 protein, which could be reversed by exportin-1 inhibitor leptomycin B. Our findings strongly support that besides the exon 12 mutation, the exon 5 mutant is another NPM1 "born to be exported" mutant critical for leukemogenesis. Therefore, similar to the classic type A mutation, the identification of our novel NPM1 mutation is beneficial for clinical laboratory diagnosis, genetic risk assessment and MRD monitoring.

NPM1-mutated acute myeloid leukemia: New pathogenetic and therapeutic insights and open questions

The nucleophosmin (NPM1) gene encodes for a multifunctional chaperone protein that is localized in the nucleolus but continuously shuttles between the nucleus and cytoplasm. NPM1 mutations occur in about one-third of AML, are AML-specific, usually involve exon 12 and are frequently associated with FLT3-ITD, DNMT3A, TET2, and IDH1/2 mutations. Because of its unique molecular and clinico-pathological features, NPM1-mutated AML is regarded as a distinct leukemia entity in both the International Consensus Classification (ICC) and the 5th edition of the World Health Organization (WHO) classification of myeloid neoplasms. All NPM1 mutations generate leukemic mutants that are aberrantly exported in the cytoplasm of the leukemic cells and are relevant to the pathogenesis of the disease. Here, we focus on recently identified functions of the NPM1 mutant at chromatin level and its relevance in driving HOX/MEIS gene expression. We also discuss yet controversial issues of the ICC/WHO classifications, including the biological and clinical significance of therapy-related NPM1-mutated AML and the relevance of blasts percentage in defining NPM1-mutated AML. Finally, we address the impact of new targeted therapies in NPM1-mutated AML with focus on CAR T cells directed against NPM1/HLA neoepitopes, as well as XPO1 and menin inhibitors.

The impact of SETBP1 mutations in neurological diseases and cancer

SE translocation (SET) is a cancer-promoting factor whose expression is upregulated in many cancers. High SET expression positively correlates with a poor cancer prognosis. SETBP1 (SET-binding protein 1/SEB/MRD29), identified as SET-binding protein, is the causative gene of Schinzel-Giedion syndrome, which is characterized by severe intellectual disability and a distorted facial appearance. Mutations in these genetic regions are also observed in some blood cancers, such as myelodysplastic syndromes, and are associated with a poor prognosis. However, the physiological role of SETBP1 and the molecular mechanisms by which the mutations lead to disease progression have not yet been fully elucidated. In this review, we will describe the current epidemiological data on SETBP1 mutations and shed light on the current knowledge about the SET-dependent and -independent functions of SETBP1.

NPM1-Mutated Acute Myeloid Leukemia: Recent Developments and Open Questions

Somatic mutations in the nucleophosmin (NPM1) gene occur in approximately 30% of de novo acute myeloid leukemias (AMLs) and are relatively enriched in normal karyotype AMLs. Earlier World Health Organization (WHO) classification schema recognized NPM1-mutated AMLs as a unique subtype of AML, while the latest WHO and International Consensus Classification (ICC) now consider NPM1 mutations as AML-defining, albeit at different blast count thresholds. NPM1 mutational load correlates closely with disease status, particularly in the post-therapy setting, and therefore high sensitivity-based methods for detection of the mutant allele have proven useful for minimal/measurable residual disease (MRD) monitoring. MRD status has been conventionally measured by either multiparameter flow cytometry (MFC) and/or molecular diagnostic techniques, although recent data suggest that MFC data may be potentially more challenging to interpret in this AML subtype. Of note, MRD status does not predict patient outcome in all cases, and therefore a deeper understanding of the biological significance of MRD may be required. Recent studies have confirmed that NPM1-mutated cells rely on overexpression of HOX/MEIS1, which is dependent on the presence of the aberrant cytoplasmic localization of mutant NPM1 protein (NPM1c); this biology may explain the promising response to novel agents, including menin inhibitors and second-generation XPO1 inhibitors. In this review, these and other recent developments around NPM1-mutated AML, in addition to open questions warranting further investigation, will be discussed.

Comparison of the International Consensus and 5th WHO edition classifications of adult myelodysplastic syndromes and acute myeloid leukemia

Several editions of the World Health Organization (WHO) classifications of lympho-hemopoietic neoplasms in 2001, 2008, and 2016 served as the international standard for diagnosis. Since the 4th WHO edition, here referred as WHO-HAEM4, significant clinico-pathological, immunophenotypic, and molecular advances have been made in the field of myeloid neoplasms, which have contributed to refine diagnostic criteria, to upgrade entities previously defined as provisional and to identify new entities. This process has resulted in two recent classification proposals of myeloid neoplasms: the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, with a focus on adult myelodysplastic syndromes/neoplasms (MDS) and acute myeloid leukemia (AML). The goal is to provide a tool to facilitate the work of pathologists, hematologists and researchers involved in the diagnosis and treatment of these hematological malignancies.

Targeting and Monitoring Acute Myeloid Leukaemia with Nucleophosmin-1 (NPM1) Mutation

Mutations in NPM1, also known as nucleophosmin-1, B23, NO38, or numatrin, are seen in approximately one-third of patients with acute myeloid leukaemia (AML). A plethora of treatment strategies have been studied to determine the best possible approach to curing NPM1-mutated AML. Here, we introduce the structure and function of NPM1 and describe the application of minimal residual disease (MRD) monitoring using molecular methods by means of quantitative polymerase chain reaction (qPCR), droplet digital PCR (ddPCR), next-generation sequencing (NGS), and cytometry by time of flight (CyTOF) to target NPM1-mutated AML. Current drugs, now regarded as the standard of care for AML, as well as potential drugs still under development, will also be explored. This review will focus on the role of targeting aberrant NPM1 pathways such as BCL-2 and SYK; as well as epigenetic regulators (RNA polymerase), DNA intercalators (topoisomerase II), menin inhibitors, and hypomethylating agents. Aside from medication, the effects of stress on AML presentation have been reported, and some possible mechanisms outlined. Moreover, targeted strategies will be briefly discussed, not only for the prevention of abnormal trafficking and localisation of cytoplasmic NPM1 but also for the elimination of mutant NPM1 proteins. Lastly, the advancement of immunotherapy such as targeting CD33, CD123, and PD-1 will be mentioned.

Cytoplasmic Expression of TP53INP2 Modulated by Demethylase FTO and Mutant NPM1 Promotes Autophagy in Leukemia Cells

Acute myeloid leukemia (AML) with a nucleophosmin 1 (NPM1) mutation is a unique subtype of adult leukemia. Recent studies show that NPM1-mutated AML has high autophagy activity. However, the mechanism for upholding the high autophagic level is still not fully elucidated. In this study, we first identified that tumor protein p53 inducible nuclear protein 2 (TP53INP2) was highly expressed and cytoplasmically localized in NPM1-mutated AML cells. Subsequent data showed that the expression of TP53INP2 was upregulated by fat mass and obesity-associated protein (FTO)-mediated m⁶A modification. Meanwhile, TP53INP2 was delocalized to the cytoplasm by interacting with NPM1 mutants. Functionally, cytoplasmic TP53INP2 enhanced autophagy activity by promoting the interaction of microtubule-associated protein 1 light chain 3 (LC3) - autophagy-related 7 (ATG7) and further facilitated the survival of leukemia cells. Taken together, our study indicates that TP53INP2 plays an oncogenic role in maintaining the high autophagy activity of NPM1-mutated AML and provides further insight into autophagy-targeted therapy of this leukemia subtype.

Genomic profiling for clinical decision making in myeloid neoplasms and acute leukemia

Myeloid neoplasms and acute leukemias derive from the clonal expansion of hematopoietic cells driven by somatic gene mutations. Although assessment of morphology plays a crucial role in the diagnostic evaluation of patients with these malignancies, genomic characterization has become increasingly important for accurate diagnosis, risk assessment, and therapeutic decision making. Conventional cytogenetics, a comprehensive and unbiased method for assessing chromosomal abnormalities, has been the mainstay of genomic testing over the past several decades and remains relevant today. However, more recent advances in sequencing technology have increased our ability to detect somatic mutations through the use of targeted gene panels, whole-exome sequencing, whole-genome sequencing, and whole-transcriptome sequencing or RNA sequencing. In patients with myeloid neoplasms, whole-genome sequencing represents a potential replacement for both conventional cytogenetic and sequencing approaches, providing rapid and accurate comprehensive genomic profiling. DNA sequencing methods are used not only for detecting somatically acquired gene mutations but also for identifying germline gene mutations associated with inherited predisposition to hematologic neoplasms. The 2022 International Consensus Classification of myeloid neoplasms and acute leukemias makes extensive use of genomic data. The aim of this report is to help physicians and laboratorians implement genomic testing for diagnosis, risk stratification, and clinical decision making and illustrates the potential of genomic profiling for enabling personalized medicine in patients with hematologic neoplasms.

From Serendipity to Rational Identification of the 5,6,7,8-Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4(3H)-one Core as a New Chemotype of AKT1 Inhibitors for Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous hematopoietic malignancy whose prognosis is globally poor. In more than 60% of AML patients, the PI3K/AKTs/mTOR signaling pathway is aberrantly activated because of oncogenic driver alterations and further enhanced by chemotherapy as a mechanism of drug resistance. Against this backdrop, very recently we have started a multidisciplinary research project focused on AKT1 as a pharmacological target to identify novel anti-AML agents. Indeed, the serendipitous finding of the in-house compound T187 as an AKT1 inhibitor has paved the way to the rational identification of new active small molecules, among which T126 has emerged as the most interesting compound with IC₅₀ = 1.99 ± 0.11 μM, ligand efficiency of 0.35, and a clear effect at low micromolar concentrations on growth inhibition and induction of apoptosis in AML cells. The collected results together with preliminary SAR data strongly indicate that the 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4(3H)-one derivative T126 is worthy of future biological experiments and medicinal chemistry efforts aimed at developing a novel chemical class of AKT1 inhibitors as anti-AML agents.

New insights into the role of ribonuclease P protein subunit p30 from tumor to internal reference

Ribonuclease P protein subunit p30 (RPP30) is a highly conserved housekeeping gene that exists in many species and tissues throughout the three life kingdoms (archaea, bacteria, and eukaryotes). RPP30 is closely related to a few types of tumors in human diseases but has a very stable transcription level in most cases. Based on this feature, increasing number of studies have used RPP30 as an internal reference gene. Here, the structure and basic functions of RPP30 are summarized and the likely relationship between RPP30 and various diseases in plants and human is outlined. Finally, the current application of RPP30 as an internal reference gene and its advantages over traditional internal reference genes are reviewed. RPP30 characteristics suggest that it has a good prospect of being selected as an internal reference; more work is needed to develop this research avenue.

The Down-Regulation of Circ_0059707 in Acute Myeloid Leukemia Promotes Cell Growth and Inhibits Apoptosis by Regulating miR-1287-5p

Acute myeloid leukemia (AML) is the most common type of hematological malignancy. Recently, an increasing number of reports have shown that many circular RNAs can act as effective targets for AML. However, the roles of circ_0059707 in AML remain largely unclear. In this study, we found that the expression levels of circ_0059707 were significantly decreased in AML patients with respect to normal controls (p < 0.001). Low expression levels of circ_0059707 were also associated with a poor prognosis. Furthermore, circ_0059707 overexpression inhibited cell growth and promoted apoptosis in leukemia cells, compared with control cells. Circ_0059707- and empty plasmid-transfected cells were injected subcutaneously into BALB/c nude mice. We found that the tumor volume was significantly lower in mice in the circ_0059707 group than in control mice (p < 0.01). Nuclear pyknosis, nuclear fragmentation, nuclear dissolution, and cell necrosis were observed in the circ_0059707 group by HE staining. CircInteractome analysis showed that 25 microRNAs (miRNAs), including miR-1287-5p, ©-miR-1825, a©hsa-miR-326, may be potential targets for circ_0059707. The expression of these miRNAs was analyzed in both the GEO GSE51908 and the GSE142700 databases. miR-1287-5p expression was lower in AML patients compared with controls in both the GSE51908 and the GSE142700 datasets. Moreover, we demonstrated that miR-1287-5p expression was down-regulated in AML patients and up-regulated in circ_0059707-overexpressing cells. Collectively, our research demonstrated that the down-regulation of circ_0059707 was highly evident in de novo AML patients. Our analysis also demonstrated that circ_0059707 inhibited cell growth and promoted apoptosis by up-regulating miR-1287-5p.

Atypical Rearrangements in APL-Like Acute Myeloid Leukemias: Molecular Characterization and Prognosis

Acute promyelocytic leukemia (APL) accounts for 10–15% of newly diagnosed acute myeloid leukemias (AML) and is typically caused by the fusion of promyelocytic leukemia with retinoic acid receptor α (RARA) gene. The prognosis is excellent, thanks to the all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) combination therapy. A small percentage of APLs (around 2%) is caused by atypical transcripts, most of which involve RARA or other members of retinoic acid receptors (RARB or RARG). The diagnosis of these forms is difficult, and clinical management is still a challenge for the physician due to variable response rates to ATRA and ATO. Herein we review variant APL cases reported in literature, including genetic landscape, incidence of coagulopathy and differentiation syndrome, frequent causes of morbidity and mortality in these patients, sensitivity to ATRA, ATO, and chemotherapy, and outcome. We also focus on non-RAR rearrangements, complex rearrangements (involving more than two chromosomes), and NPM1-mutated AML, an entity that can, in some cases, morphologically mimic APL.

Significance of NPM1 Gene Mutations in AML

The aim of this literature review is to examine the significance of the nucleophosmin 1 (NPM1) gene in acute myeloid leukaemia (AML). This will include analysis of the structure and normal cellular function of NPM1, the type of mutations commonly witnessed in NPM1, and the mechanism by which this influences the development and progression of AML. The importance of NPM1 mutation on prognosis and the treatment options available to patients will also be reviewed along with current guidelines recommending the rapid return of NPM1 mutational screening results and the importance of employing a suitable laboratory assay to achieve this. Finally, future developments in the field including research into new therapies targeting NPM1 mutated AML are considered.

A Curious Novel Combination of Nucleophosmin (NPM1) Gene Mutations Leading to Aberrant Cytoplasmic Dislocation of NPM1 in Acute Myeloid Leukemia (AML)

Nucleophosmin (NPM1) mutations occurring in acute myeloid leukemia (AML) (about 50 so far identified) cluster almost exclusively in exon 12 and lead to common changes at the NPM1 mutants C-terminus, i.e., loss of tryptophans 288 and 290 (or 290 alone) and creation of a new nuclear export signal (NES), at the bases of exportin-1(XPO1)-mediated aberrant cytoplasmic NPM1. Immunohistochemistry (IHC) detects cytoplasmic NPM1 and is predictive of the molecular alteration. Besides IHC and molecular sequencing, Western blotting (WB) with anti-NPM1 mutant specific antibodies is another approach to identify NPM1-mutated AML. Here, we show that among 382 AML cases with NPM1 exon 12 mutations, one was not recognized by WB, and describe the discovery of a novel combination of two mutations involving exon 12. This appeared as a conventional mutation A with the known TCTG nucleotides insertion/duplication accompanied by a second event (i.e., an 8-nucleotide deletion occurring 15 nucleotides downstream of the TCTG insertion), resulting in a new C-terminal protein sequence. Strikingly, the sequence included a functional NES ensuring cytoplasmic relocation of the new mutant supporting the role of cytoplasmic NPM1 as critical in AML leukemogenesis.