Expression of the O-Linked N-Acetylglucosamine-containing Epitope H (O-GlcNAcH) in Human Uterine Cervical Mucosa.

BACKGROUND/AIM: Epitope H contains an O-linked N-acetylglucosamine (O-GlcNAcH) residue in a specific conformation or environment, recognized by a site-specific monoclonal mouse IgM antibody H. O-GlcNAcH occurs in several normal and pathological cells and in several polypeptides, including keratin-8 and vimentin, on the latter in cells under stress. MATERIALS AND METHODS: In this work, we studied the distribution of O-GlcNAcH on cells of endocervical mucosa in 60 specimens of endocervical curettings, 10 of which contained 15 inflamed polyps. RESULTS: In our results, expression of O-GlcNAcH was weak in the mucosa with <5% mucin-secreting cells and up to 30% of the polyps staining positively. All non-ciliated, non-mucin-secreting cells, normal and hyperplastic 'reserve' cells, as well as the cells of immature squamous metaplasia, showed strong diffuse cytoplasmic staining for O-GlcNAcH. In mature squamous epithelium, fewer than 5% of basal cells and all the intermediate and superficial cells showed cytoplasmic staining for O-GlcNAcH, whereas parabasal cells were negative. All ciliated cells showed patchy or diffuse cytoplasmic staining. Nuclear staining for O-GlcNAcH was weak with fewer than 5% of hyperplastic 'reserve' and ciliated cells staining positively. Moreover, mucosal fibroblasts were negative, whereas all stromal cells of the polyps showed strong cytoplasmic staining for O-GlcNAcH. CONCLUSION: O-GlcNAcH is: a) differentially expressed among the cellular elements of mucosa and polyps, b) upregulated in mucin-secreting cells of polyps, c) induced in stromal cells of inflamed polyps, and d) can be used as a marker to differentiate between 'reserve' (positive) and parabasal (negative) cells, which have similar morphology using conventional cytological stains.

Primary Paraganglioma of the Prostate: A Systematic Review of the Literature for A Rare Entity.

BACKGROUND: Paragangliomas of the urinary tract are exceptionally uncommon, and sporadic case reports of primary paraganglioma of the prostate have been reported in the literature. METHODS: Systematic research in PubMed/Medline and Scopus databases concerning primary prostatic paraganglioma was performed by two independent investigators. RESULTS: This analysis included 25 adult males, with a mean age of 49.8 ± 22.4 years. 32% of included patients had a history of hypertension. Problems during urination (52%), blood loss (44%), either as hematuria or hemospermia, and catecholamine-related symptoms (36%) comprised the most frequently reported clinical manifestations. Digital rectal examination found a palpable nodule in 36% of patients, while prostatic specific antigen (PSA) was normal in all tested patients. Abdominal ultrasound (44%), computed tomography (44%) and magnetic resonance imaging (28%) helped to identify the primary lesion. 24-hour urine epinephrine, norepinephrine and vanillylmandelic acid (VMA) levels were elevated in 90%, 80% and 90% of included patients. Open surgical excision of the mass was performed in 40%, transurethral resection in 8%, open radical prostatectomy in 24%, transurethral resection of the prostate in 16% and robot-assisted radical prostatectomy in 4% of included patients. CONCLUSION: Due to atypical clinical manifestation and scarcity of prostatic paraganglioma, urologists should be aware of this extremely rare entity.

Diagnosis and Management of Intrascrotal Nerve Tumors: A Systematic Review of the Literature.

Scrotal tumors of nerve origin are extremely rare and occur mostly in the extratesticular tissues of scrotum, such as the spermatic cord and epididymis. A systematic search of the literature in PubMed, Medline, and Google Scholar databases concerning intrascrotal nerve tumors was performed by 2 independent investigators. The systematic search retrieved 45 male adults, with a mean age of included patients at 43.9 ± 18.8 years. The majority of nerve tumors were extra-testicular (86.7%), and only 13.3% originated from the testis. Out of that, 51.1% of neoplasms were histologically proved as schwannomas, 44.4% as neurofibromatosis, and 4.4% as malignant peripheral nerve sheath tumors. The majority of patients presented with atypical symptoms such as scrotal swelling (51.1%), while only 4.4% of patients were asymptomatic. Ultrasonography is the diagnostic modality of choice (97.2%) for the detection of primary lesion, while magnetic resonance imaging and computed tomography comprise supplementary diagnostic tools. Surgical excision of the mass was the preferred type of surgery performed (75.6%), whereas orchiectomy was performed only in 22.2% of patients. Intrascrotal tumors of nerve origin are extremely rare neoplasms that present mainly in middle-aged males. Increased clinical suspicion is required for accurate diagnosis of this rare entity.

Large Cyst of Skene Gland: A Rare Perineum Mass.

Objective In this report we present a rare case of a large cyst of Skene gland in a female patient with a palpable vaginal mass persisting for at least 2 years. Case Report A 67-year-old female admitted to the department of urology due to the presence of "a vaginal mass" for the past 2 years. A cyst of Skene's duct was suspected based on clinical manifestation and findings of magnetic resonance imaging showing an extensive cyst formation in the upper vaginal area and anterior to the urethra. Based on these findings, a decision for surgical removement of the cyst was made. The cyst was incised, drained, and marsupialized. The postoperative recovery was uneventful, and the patient was discharged on the second postoperative day. Conclusion High clinical suspicion is important to reach this rare diagnosis. Partial excision and marsupialization of the cyst is a simple procedure with low morbidity, without recurrence, and excellent results.

Mannose metabolism inhibition sensitizes acute myeloid leukaemia cells to therapy by driving ferroptotic cell death.

Resistance to standard and novel therapies remains the main obstacle to cure in acute myeloid leukaemia (AML) and is often driven by metabolic adaptations which are therapeutically actionable. Here we identify inhibition of mannose-6-phosphate isomerase (MPI), the first enzyme in the mannose metabolism pathway, as a sensitizer to both cytarabine and FLT3 inhibitors across multiple AML models. Mechanistically, we identify a connection between mannose metabolism and fatty acid metabolism, that is mediated via preferential activation of the ATF6 arm of the unfolded protein response (UPR). This in turn leads to cellular accumulation of polyunsaturated fatty acids, lipid peroxidation and ferroptotic cell death in AML cells. Our findings provide further support to the role of rewired metabolism in AML therapy resistance, unveil a connection between two apparently independent metabolic pathways and support further efforts to achieve eradication of therapy-resistant AML cells by sensitizing them to ferroptotic cell death.

Maternal serum pregnancy-associated plasma protein-A concentration at 11-14 weeks of gestation and preeclampsia risk of women with common congenital anatomic uterine abnormalities.

To evaluate maternal serum pregnancy-associated plasma protein-A (PAPP-A) levels at 11-14 weeks of gestation and preeclampsia risk in women with common congenital anatomic uterine abnormalities (AUAs). First trimester screening markers were compared between 12 AUA pregnancies, 60 age matched controls and 12 cases of early preeclampsia. PAPP-A level and birth weight were significantly lower in AUA compared to control and early preeclampsia group (p<.001). Preeclampsia was absent in the AUAs pregnancies group. Birth weight were similar in AUA group when we compared AUA and control group regarding weeks of gestation at delivery and lower but not significantly, when we compared AUA and early preeclampsia group. Our findings suggest that AUA pregnancies are associated with low first trimester maternal serum PAPP-A concentrations not predictive of susceptibility to preeclampsia.Impact statementWhat is already known on this subject? During first trimester screening for preeclampsia based on maternal pregnancy-associated plasma protein A (PAPP-A) levels, various parameters are used, such as the somatometric characteristics of pregnant woman, single or multiple pregnancy, smoking status, family history, diabetes, hypertension and measurement of blood pressure and uterine artery Dopplers.What do the results of this study add? Our pioneer study revealed that there is drastic difference in PAPP-A concentration in women with common anatomic uterine abnormalities (AUAs), in comparison with their age matched control women with normal uterus.What are the implications of these findings for clinical practice and further research? Based on our results, uterine anatomical deviations, is another factor which must be taken in account for preeclampsia risk calculation and further clinical consultation and follow up in those pregnancies. Lower PAPP-A levels in AUA cases is a weak predictor of susceptibility to preeclampsia and could be associated to smaller placental size rather than poor placentation and in future research the calculation of the uterine cavity functional dimension may lead to a more accurate clinical assessment.

METTL1-mediated m7G modification of Arg-TCT tRNA drives oncogenic transformation.

The emerging "epitranscriptomics" field is providing insights into the biological and pathological roles of different RNA modifications. The RNA methyltransferase METTL1 catalyzes N7-methylguanosine (m7G) modification of tRNAs. Here we find METTL1 is frequently amplified and overexpressed in cancers and is associated with poor patient survival. METTL1 depletion causes decreased abundance of m7G-modified tRNAs and altered cell cycle and inhibits oncogenicity. Conversely, METTL1 overexpression induces oncogenic cell transformation and cancer. Mechanistically, we find increased abundance of m7G-modified tRNAs, in particular Arg-TCT-4-1, and increased translation of mRNAs, including cell cycle regulators that are enriched in the corresponding AGA codon. Accordingly, Arg-TCT expression is elevated in many tumor types and is associated with patient survival, and strikingly, overexpression of this individual tRNA induces oncogenic transformation. Thus, METTL1-mediated tRNA modification drives oncogenic transformation through a remodeling of the mRNA "translatome" to increase expression of growth-promoting proteins and represents a promising anti-cancer target.

SETBP1 overexpression acts in the place of class-defining mutations to drive FLT3-ITD-mutant AML.

Advances in cancer genomics have revealed genomic classes of acute myeloid leukemia (AML) characterized by class-defining mutations, such as chimeric fusion genes or in genes such as NPM1, MLL, and CEBPA. These class-defining mutations frequently synergize with internal tandem duplications in FLT3 (FLT3-ITDs) to drive leukemogenesis. However, ∼20% of FLT3-ITD-positive AMLs bare no class-defining mutations, and mechanisms of leukemic transformation in these cases are unknown. To identify pathways that drive FLT3-ITD mutant AML in the absence of class-defining mutations, we performed an insertional mutagenesis (IM) screening in Flt3-ITD mice, using Sleeping Beauty transposons. All mice developed acute leukemia (predominantly AML) after a median of 73 days. Analysis of transposon insertions in 38 samples from Flt3-ITD/IM leukemic mice identified recurrent integrations at 22 loci, including Setbp1 (20/38), Ets1 (11/38), Ash1l (8/38), Notch1 (8/38), Erg (7/38), and Runx1 (5/38). Insertions at Setbp1 led exclusively to AML and activated a transcriptional program similar, but not identical, to those of NPM1-mutant and MLL-rearranged AMLs. Guide RNA targeting of Setbp1 was highly detrimental to Flt3ITD/+/Setbp1IM+, but not to Flt3ITD/+/Npm1cA/+, AMLs. Also, analysis of RNA-sequencing data from hundreds of human AMLs revealed that SETBP1 expression is significantly higher in FLT3-ITD AMLs lacking class-defining mutations. These findings propose that SETBP1 overexpression collaborates with FLT3-ITD to drive a subtype of human AML. To identify genetic vulnerabilities of these AMLs, we performed genome-wide CRISPR-Cas9 screening in Flt3ITD/+/Setbp1IM+ AMLs and identified potential therapeutic targets, including Kdm1a, Brd3, Ezh2, and Hmgcr. Our study gives new insights into epigenetic pathways that can drive AMLs lacking class-defining mutations and proposes therapeutic approaches against such cases.

Small-molecule inhibition of METTL3 as a strategy against myeloid leukaemia.

N6-methyladenosine (m6A) is an abundant internal RNA modification1,2 that is catalysed predominantly by the METTL3-METTL14 methyltransferase complex3,4. The m6A methyltransferase METTL3 has been linked to the initiation and maintenance of acute myeloid leukaemia (AML), but the potential of therapeutic applications targeting this enzyme remains unknown5-7. Here we present the identification and characterization of STM2457, a highly potent and selective first-in-class catalytic inhibitor of METTL3, and a crystal structure of STM2457 in complex with METTL3-METTL14. Treatment of tumours with STM2457 leads to reduced AML growth and an increase in differentiation and apoptosis. These cellular effects are accompanied by selective reduction of m6A levels on known leukaemogenic mRNAs and a decrease in their expression consistent with a translational defect. We demonstrate that pharmacological inhibition of METTL3 in vivo leads to impaired engraftment and prolonged survival in various mouse models of AML, specifically targeting key stem cell subpopulations of AML. Collectively, these results reveal the inhibition of METTL3 as a potential therapeutic strategy against AML, and provide proof of concept that the targeting of RNA-modifying enzymes represents a promising avenue for anticancer therapy.

KAT7 is a genetic vulnerability of acute myeloid leukemias driven by MLL rearrangements.

Histone acetyltransferases (HATs) catalyze the transfer of an acetyl group from acetyl-CoA to lysine residues of histones and play a central role in transcriptional regulation in diverse biological processes. Dysregulation of HAT activity can lead to human diseases including developmental disorders and cancer. Through genome-wide CRISPR-Cas9 screens, we identified several HATs of the MYST family as fitness genes for acute myeloid leukemia (AML). Here we investigate the essentiality of lysine acetyltransferase KAT7 in AMLs driven by the MLL-X gene fusions. We found that KAT7 loss leads to a rapid and complete loss of both H3K14ac and H4K12ac marks, in association with reduced proliferation, increased apoptosis, and differentiation of AML cells. Acetyltransferase activity of KAT7 is essential for the proliferation of these cells. Mechanistically, our data propose that acetylated histones provide a platform for the recruitment of MLL-fusion-associated adaptor proteins such as BRD4 and AF4 to gene promoters. Upon KAT7 loss, these factors together with RNA polymerase II rapidly dissociate from several MLL-fusion target genes that are essential for AML cell proliferation, including MEIS1, PBX3, and SENP6. Our findings reveal that KAT7 is a plausible therapeutic target for this poor prognosis AML subtype.

The N6-methyladenosine RNA modification in acute myeloid leukemia.

PURPOSE OF REVIEW: In recent years, the N6-methyladenosine (m6A) modification of RNA has been shown to play an important role in the development of acute myeloid leukemia (AML) and the maintenance of leukemic stem cells (LSCs). In this review we summarise the recent findings in the field of epitranscriptomics related to m6A and its relevance in AML. RECENT FINDINGS: Recent studies have focused on the role of m6A regulators in the development of AML and their potential as translational targets. The writer Methyltransferase Like 3 and its binding partner Methyltransferase Like 14, as well as the reader YTH domain-containing family protein 2, were shown to be vital for LSC survival, and their loss has detrimental effects on AML cells. Similar observations were made with the demethylases fat mass and obesity-associated protein and AlkB homologue 5 RNA demethylase. Of importance, loss of any of these genes has little to no effect on normal hemopoietic stem cells, suggesting therapeutic potential. SUMMARY: The field of epitranscriptomics is still in its infancy and the importance of m6A and other RNA-modifications in AML will only come into sharper focus. The development of therapeutics targeting RNA-modifying enzymes may open up new avenues for treatment of such malignancies.

Dissecting the early steps of MLL induced leukaemogenic transformation using a mouse model of AML.

Leukaemogenic mutations commonly disrupt cellular differentiation and/or enhance proliferation, thus perturbing the regulatory programs that control self-renewal and differentiation of stem and progenitor cells. Translocations involving the Mll1 (Kmt2a) gene generate powerful oncogenic fusion proteins, predominantly affecting infant and paediatric AML and ALL patients. The early stages of leukaemogenic transformation are typically inaccessible from human patients and conventional mouse models. Here, we take advantage of cells conditionally blocked at the multipotent haematopoietic progenitor stage to develop a MLL-r model capturing early cellular and molecular consequences of MLL-ENL expression based on a clear clonal relationship between parental and leukaemic cells. Through a combination of scRNA-seq, ATAC-seq and genome-scale CRISPR-Cas9 screening, we identify pathways and genes likely to drive the early phases of leukaemogenesis. Finally, we demonstrate the broad utility of using matched parental and transformed cells for small molecule inhibitor studies by validating both previously known and other potential therapeutic targets.

Correction: Premature activation of Cdk1 leads to mitotic events in S phase and embryonic lethality.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Premature activation of Cdk1 leads to mitotic events in S phase and embryonic lethality.

Cell cycle regulation, especially faithful DNA replication and mitosis, are crucial to maintain genome stability. Cyclin-dependent kinase (CDK)/cyclin complexes drive most processes in cellular proliferation. In response to DNA damage, cell cycle surveillance mechanisms enable normal cells to arrest and undergo repair processes. Perturbations in genomic stability can lead to tumor development and suggest that cell cycle regulators could be effective targets in anticancer therapy. However, many clinical trials ended in failure due to off-target effects of the inhibitors used. Here, we investigate in vivo the importance of WEE1- and MYT1-dependent inhibitory phosphorylation of mammalian CDK1. We generated Cdk1AF knockin mice, in which two inhibitory phosphorylation sites are replaced by the non-phosphorylatable amino acids T14A/Y15F. We uncovered that monoallelic expression of CDK1AF is early embryonic lethal in mice and induces S phase arrest accompanied by γH2AX and DNA damage checkpoint activation in mouse embryonic fibroblasts (MEFs). The chromosomal fragmentation in Cdk1AF MEFs does not rely on CDK2 and is partly caused by premature activation of MUS81-SLX4 structure-specific endonuclease complexes, as well as untimely onset of chromosome condensation followed by nuclear lamina disassembly. We provide evidence that tumor development in liver expressing CDK1AF is inhibited. Interestingly, the regulatory mechanisms that impede cell proliferation in CDK1AF expressing cells differ partially from the actions of the WEE1 inhibitor, MK-1775, with p53 expression determining the sensitivity of cells to the drug response. Thus, our work highlights the importance of improved therapeutic strategies for patients with various cancer types and may explain why some patients respond better to WEE1 inhibitors.

SRPK1 maintains acute myeloid leukemia through effects on isoform usage of epigenetic regulators including BRD4.

We recently identified the splicing kinase gene SRPK1 as a genetic vulnerability of acute myeloid leukemia (AML). Here, we show that genetic or pharmacological inhibition of SRPK1 leads to cell cycle arrest, leukemic cell differentiation and prolonged survival of mice transplanted with MLL-rearranged AML. RNA-seq analysis demonstrates that SRPK1 inhibition leads to altered isoform levels of many genes including several with established roles in leukemogenesis such as MYB, BRD4 and MED24. We focus on BRD4 as its main isoforms have distinct molecular properties and find that SRPK1 inhibition produces a significant switch from the short to the long isoform at the mRNA and protein levels. This was associated with BRD4 eviction from genomic loci involved in leukemogenesis including BCL2 and MYC. We go on to show that this switch mediates at least part of the anti-leukemic effects of SRPK1 inhibition. Our findings reveal that SRPK1 represents a plausible new therapeutic target against AML.

UTX-mediated enhancer and chromatin remodeling suppresses myeloid leukemogenesis through noncatalytic inverse regulation of ETS and GATA programs.

The histone H3 Lys27-specific demethylase UTX (or KDM6A) is targeted by loss-of-function mutations in multiple cancers. Here, we demonstrate that UTX suppresses myeloid leukemogenesis through noncatalytic functions, a property shared with its catalytically inactive Y-chromosome paralog, UTY (or KDM6C). In keeping with this, we demonstrate concomitant loss/mutation of KDM6A (UTX) and UTY in multiple human cancers. Mechanistically, global genomic profiling showed only minor changes in H3K27me3 but significant and bidirectional alterations in H3K27ac and chromatin accessibility; a predominant loss of H3K4me1 modifications; alterations in ETS and GATA-factor binding; and altered gene expression after Utx loss. By integrating proteomic and genomic analyses, we link these changes to UTX regulation of ATP-dependent chromatin remodeling, coordination of the COMPASS complex and enhanced pioneering activity of ETS factors during evolution to AML. Collectively, our findings identify a dual role for UTX in suppressing acute myeloid leukemia via repression of oncogenic ETS and upregulation of tumor-suppressive GATA programs.

Glutaminolysis is a metabolic dependency in FLT3ITD acute myeloid leukemia unmasked by FLT3 tyrosine kinase inhibition.

FLT3 internal tandem duplication (FLT3ITD) mutations are common in acute myeloid leukemia (AML) associated with poor patient prognosis. Although new-generation FLT3 tyrosine kinase inhibitors (TKI) have shown promising results, the outcome of FLT3ITD AML patients remains poor and demands the identification of novel, specific, and validated therapeutic targets for this highly aggressive AML subtype. Utilizing an unbiased genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 screen, we identify GLS, the first enzyme in glutamine metabolism, as synthetically lethal with FLT3-TKI treatment. Using complementary metabolomic and gene-expression analysis, we demonstrate that glutamine metabolism, through its ability to support both mitochondrial function and cellular redox metabolism, becomes a metabolic dependency of FLT3ITD AML, specifically unmasked by FLT3-TKI treatment. We extend these findings to AML subtypes driven by other tyrosine kinase (TK) activating mutations and validate the role of GLS as a clinically actionable therapeutic target in both primary AML and in vivo models. Our work highlights the role of metabolic adaptations as a resistance mechanism to several TKI and suggests glutaminolysis as a therapeutically targetable vulnerability when combined with specific TKI in FLT3ITD and other TK activating mutation-driven leukemias.

Promoter-bound METTL3 maintains myeloid leukaemia by m6A-dependent translation control.

N6-methyladenosine (m6A) is an abundant internal RNA modification in both coding and non-coding RNAs that is catalysed by the METTL3-METTL14 methyltransferase complex. However, the specific role of these enzymes in cancer is still largely unknown. Here we define a pathway that is specific for METTL3 and is implicated in the maintenance of a leukaemic state. We identify METTL3 as an essential gene for growth of acute myeloid leukaemia cells in two distinct genetic screens. Downregulation of METTL3 results in cell cycle arrest, differentiation of leukaemic cells and failure to establish leukaemia in immunodeficient mice. We show that METTL3, independently of METTL14, associates with chromatin and localizes to the transcriptional start sites of active genes. The vast majority of these genes have the CAATT-box binding protein CEBPZ present at the transcriptional start site, and this is required for recruitment of METTL3 to chromatin. Promoter-bound METTL3 induces m6A modification within the coding region of the associated mRNA transcript, and enhances its translation by relieving ribosome stalling. We show that genes regulated by METTL3 in this way are necessary for acute myeloid leukaemia. Together, these data define METTL3 as a regulator of a chromatin-based pathway that is necessary for maintenance of the leukaemic state and identify this enzyme as a potential therapeutic target for acute myeloid leukaemia.