Situational awareness: regulation of the myb transcription factor in differentiation, the cell cycle and oncogenesis

Emerging role of MYB transcription factors in cancer drug resistance

Decades ago, the viral myeloblastosis oncogene v-myb was identified as a gene responsible for the development of avian leukemia. However, the relevance of MYB proteins for human cancer diseases, in particular for solid tumors, remained basically unrecognized for a very long time. The human family of MYB transcription factors comprises MYB (c-MYB), MYBL2 (b-MYB), and MYBL1 (a-MYB), which are overexpressed in several cancers and are associated with cancer progression and resistance to anticancer drugs. In addition to overexpression, the presence of activated MYB-fusion proteins as tumor drivers was described in certain cancers. The identification of anticancer drug resistance mediated by MYB proteins and their underlying mechanisms are of great importance in understanding failures of current therapies and establishing new and more efficient therapy regimens. In addition, new drug candidates targeting MYB transcription factor activity and signaling have emerged as a promising class of potential anticancer therapeutics that could tackle MYB-dependent drug-resistant cancers in a more selective way. This review describes the correlation of MYB transcription factors with the formation and persistence of cancer resistance to various approved and investigational anticancer drugs.

Myb overexpression synergizes with the loss of Pten and is a dependency factor and therapeutic target in T-cell lymphoblastic leukemia

T-lineage acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that accounts for 10%-15% of pediatric and 25% of adult ALL cases. Although the prognosis of T-ALL has improved over time, the outcome of T-ALL patients with primary resistant or relapsed leukemia remains poor. Therefore, further progress in the treatment of T-ALL requires a better understanding of its biology and the development of more effective precision oncologic therapies. The proto-oncogene MYB is highly expressed in diverse hematologic malignancies, including T-ALLs with genomic aberrations that further potentiate its expression and activity. Previous studies have associated MYB with a malignant role in the pathogenesis of several cancers. However, its role in the induction and maintenance of T-ALL remains relatively poorly understood. In this study, we found that an increased copy number of MYB is associated with higher MYB expression levels, and might be associated with inferior event-free survival of pediatric T-ALL patients. Using our previously described conditional Myb overexpression mice, we generated two distinct MYB-driven T-ALL mouse models. We demonstrated that the overexpression of Myb synergizes with Pten deletion but not with the overexpression of Lmo2 to accelerate the development of T-cell lymphoblastic leukemias. We also showed that MYB is a dependency factor in T-ALL since RNA interference of Myb blocked cell cycle progression and induced apoptosis in both human and murine T-ALL cell lines. Finally, we provide preclinical evidence that targeting the transcriptional activity of MYB can be a useful therapeutic strategy for the treatment of T-ALL.

MYB: A Key Transcription Factor in the Hematopoietic System Subject to Many Levels of Control

MYB is a master regulator and pioneer factor highly expressed in hematopoietic progenitor cells (HPCs) where it contributes to the reprogramming processes operating during hematopoietic development. MYB plays a complex role being involved in several lineages of the hematopoietic system. At the molecular level, the MYB gene is subject to intricate regulation at many levels through several enhancer and promoter elements, through transcriptional elongation control, as well as post-transcriptional regulation. The protein is modulated by post-translational modifications (PTMs) such as SUMOylation restricting the expression of its downstream targets. Together with a range of interaction partners, cooperating transcription factors (TFs) and epigenetic regulators, MYB orchestrates a fine-tuned symphony of genes expressed during various stages of haematopoiesis. At the same time, the complex MYB system is vulnerable, being a target for unbalanced control and cancer development.

Downregulation of a transcription factor associated with resistance to Bt toxin Vip3Aa in the invasive fall armyworm

Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have revolutionized control of some major pests. However, more than 25 cases of field-evolved practical resistance have reduced the efficacy of transgenic crops producing crystalline (Cry) Bt proteins, spurring adoption of alternatives including crops producing the Bt vegetative insecticidal protein Vip3Aa. Although practical resistance to Vip3Aa has not been reported yet, better understanding of the genetic basis of resistance to Vip3Aa is urgently needed to proactively monitor, delay, and counter pest resistance. This is especially important for fall armyworm (Spodoptera frugiperda), which has evolved practical resistance to Cry proteins and is one of the world's most damaging pests. Here, we report the identification of an association between downregulation of the transcription factor gene SfMyb and resistance to Vip3Aa in S. frugiperda. Results from a genome-wide association study, fine-scale mapping, and RNA-Seq identified this gene as a compelling candidate for contributing to the 206-fold resistance to Vip3Aa in a laboratory-selected strain. Experimental reduction of SfMyb expression in a susceptible strain using RNA interference (RNAi) or CRISPR/Cas9 gene editing decreased susceptibility to Vip3Aa, confirming that reduced expression of this gene can cause resistance to Vip3Aa. Relative to the wild-type promoter for SfMyb, the promoter in the resistant strain has deletions and lower activity. Data from yeast one-hybrid assays, genomics, RNA-Seq, RNAi, and proteomics identified genes that are strong candidates for mediating the effects of SfMyb on Vip3Aa resistance. The results reported here may facilitate progress in understanding and managing pest resistance to Vip3Aa.

Integrated analysis of single-cell and bulk RNA sequencing data identifies the characteristics of ferroptosis in lumbar disc herniation

Lumbar disc herniation (LDH) is the most common condition associated with low back pain, and it adversely impacts individuals' health. Ferroptosis has recently emerged as a novel factor in the pathogenesis of LDH; however, the specific impacts of ferroptosis on LDH have not been fully elucidated. Ferroptosis-related differentially expressed genes (FRDEGs) were identified from the transcriptomic datasets of LDH. Gene set enrichment analysis (GSEA) was conducted to identify biological mechanism and related pathways. LASSO and SVM-RFE algorithms were applied to detect signature genes. Function of the signature gene was confirmed by RT-qPCR. The CIBERSORT algorithm was used to compare immune infiltration between LDH and normal samples. Correlation analysis between MYB and immune cells was analyzed using the Pearson method. Additionally, we used scRNA-seq to dissect cell clusters and cellular interactions. AUCell scoring was used to analyze the ferroptosis scores of different cell types. We found that MYB, a highly expressed ferroptosis-related gene, was associated with LDH By leveraging bioinformatics analysis. In immune infiltration analysis, the abundance of monocytes and macrophages varied significantly between the LDH group and disc spondylolisthesis (DS) group. MYB was correlated with most immune cells. GSEA revealed MYB was significantly enriched in immune-related pathways. Furthermore, scRNA-seq analysis revealed the presence of eight distinct cell types. AUCell analysis showed that macrophages had a high ferroptosis score. Cell trajectory analysis revealed that chondrocyte 1 was at the beginning of the trajectory, while calcification inhibiting chondrocytes and fibrochondrocytes accumulated along the middle and tail end of the trajectory, respectively. Cell-cell communication analysis identified chondrocyte 1 had an extensive communication network with other clusters and interacted with nucleus pulposus through collagen signaling pathway. Our analysis demonstrated that MYB may be a potential therapeutic target for LDH. This study provides a resource for the orthopedics community that will facilitate additional discoveries directedly toward understanding the pathogenesis process of LDH.

Unraveling the Role of Epithelial-Mesenchymal Transition in Adenoid Cystic Carcinoma of the Salivary Glands: A Comprehensive Review

Salivary adenoid cystic carcinoma (SACC) is considered a challenging malignancy; it is characterized by a slow-growing nature, yet a high risk of recurrence and distant metastasis, presenting significant hurdles in its treatment and management. At present, there are no approved targeted agents available for the management of SACC and systemic chemotherapy protocols that have demonstrated efficacy remain to be elucidated. Epithelial-mesenchymal transition (EMT) is a complex process that is closely associated with tumor progression and metastasis, enabling epithelial cells to acquire mesenchymal properties, including increased mobility and invasiveness. Several molecular signaling pathways have been implicated in the regulation of EMT in SACC, and understanding these mechanisms is crucial to identifying new therapeutic targets and developing more effective treatment approaches. This manuscript aims to provide a comprehensive overview of the latest research on the role of EMT in SACC, including the molecular pathways and biomarkers involved in EMT regulation. By highlighting the most recent findings, this review offers insights into potential new therapeutic strategies that could improve the management of SACC patients, especially those with recurrent or metastatic disease.

Rapid-kinetics degron benchmarking reveals off-target activities and mixed agonism-antagonism of MYB inhibitors

Attenuating aberrant transcriptional circuits holds great promise for the treatment of numerous diseases, including cancer. However, development of transcriptional inhibitors is hampered by the lack of a generally accepted functional cellular readout to characterize their target specificity and on-target activity. We benchmarked the direct gene-regulatory signatures of six agents reported as inhibitors of the oncogenic transcription factor MYB against targeted MYB degradation in a nascent transcriptomics assay. The inhibitors demonstrated partial specificity for MYB target genes but displayed significant off-target activity. Unexpectedly, the inhibitors displayed bimodal on-target effects, acting as mixed agonists-antagonists. Our data uncover unforeseen agonist effects of small molecules originally developed as TF inhibitors and argue that rapid-kinetics benchmarking against degron models should be used for functional characterization of transcriptional modulators.

MYB RNA detection by in situ hybridisation has high sensitivity and specificity for the diagnosis of adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is one of the most common primary salivary gland cancers. ACC has several benign and malignant mimics amongst salivary gland neoplasms. An accurate diagnosis of ACC is essential for optimal management of the patients and their follow-up. Upregulation of MYB has been described in 85-90% of ACC, but not in other salivary gland neoplasms. In ACC, MYB upregulation can occur as a result of a genetic rearrangement t(6;9) (q22-23;p23-24), MYB copy number variation (CNV), or enhancer hijacking of MYB. All mechanisms of MYB upregulation result in increased RNA transcription that can be detected using RNA in situ hybridisation (ISH) methods. In this study, utilising 138 primary salivary gland neoplasms including 78 ACC, we evaluate the diagnostic utility of MYB RNA ISH for distinguishing ACC from other primary salivary gland neoplasms with a prominent cribriform architecture including pleomorphic adenoma, basal cell adenoma, basal cell adenocarcinoma, epithelial myoepithelial carcinoma, and polymorphous adenocarcinoma. Fluorescent in situ hybridisation and next generation sequencing were also performed to evaluate the sensitivity and specificity of RNA ISH for detecting increased MYB RNA when MYB gene alterations were present. Detection of MYB RNA has 92.3% sensitivity and 98.2% specificity for a diagnosis of ACC amongst salivary gland neoplasms. The sensitivity of MYB RNA detection by ISH (92.3%) is significantly higher than that of the FISH MYB break-apart probe (42%) for ACC. Next generation sequencing did not demonstrate MYB alterations in cases that lacked MYB RNA overexpression indicating high sensitivity of MYB RNA ISH for detecting MYB gene alterations. The possibility that the sensitivity may be higher in clinical practice with contemporary samples as compared with older retrospective tissue samples with RNA degradation is not entirely excluded. In addition to the high sensitivity and specificity, MYB RNA testing can be performed using standard IHC platforms and protocols and evaluated using brightfield microscopy making it a time and cost-efficient diagnostic tool in routine clinical practice.

MYB sustains hypoxic survival of pancreatic cancer cells by facilitating metabolic reprogramming

Extensive desmoplasia and poor vasculature renders pancreatic tumors severely hypoxic, contributing to their aggressiveness and therapy resistance. Here, we identify the HuR/MYB/HIF1α axis as a critical regulator of the metabolic plasticity and hypoxic survival of pancreatic cancer cells. HuR undergoes nuclear-to-cytoplasmic translocation under hypoxia and stabilizes MYB transcripts, while MYB transcriptionally upregulates HIF1α. Upon MYB silencing, pancreatic cancer cells fail to survive and adapt metabolically under hypoxia, despite forced overexpression of HIF1α. MYB induces the transcription of several HIF1α-regulated glycolytic genes by directly binding to their promoters, thus enhancing the recruitment of HIF1α to hypoxia-responsive elements through its interaction with p300-dependent histone acetylation. MYB-depleted pancreatic cancer cells exhibit a dramatic reduction in tumorigenic ability, glucose-uptake and metabolism in orthotopic mouse model, even after HIF1α restoration. Together, our findings reveal an essential role of MYB in metabolic reprogramming that supports pancreatic cancer cell survival under hypoxia.

Increased retinoic acid signaling decreases lung metastasis in salivary adenoid cystic carcinoma by inhibiting the noncanonical Notch1 pathway

MYB-NFIB fusion and NOTCH1 mutation are common hallmark genetic events in salivary gland adenoid cystic carcinoma (SACC). However, abnormal expression of MYB and NOTCH1 is also observed in patients without MYB-NFIB fusion and NOTCH1 mutation. Here, we explore in-depth the molecular mechanisms of lung metastasis through single-cell RNA sequencing (scRNA-seq) and exome target capture sequencing in two SACC patients without MYB-NFIB fusion and NOTCH1 mutation. Twenty-five types of cells in primary and metastatic tissues were identified via Seurat clustering and categorized into four main stages ranging from near-normal to cancer-based on the abundance of each cell cluster in normal tissue. In this context, we identified the Notch signaling pathway enrichment in almost all cancer cells; RNA velocity, trajectory, and sub-clustering analyses were performed to deeply investigate cancer progenitor-like cell clusters in primary tumor-associated lung metastases, and signature genes of progenitor-like cells were enriched in the "MYC_TARGETS_V2" gene set. In vitro, we detected the NICD1-MYB-MYC complex by co-immunoprecipitation (Co-IP) and incidentally identified retinoic acid (RA) as an endogenous antagonist of genes in the "MYC_TARGETS_V2" gene set. Following this, we confirmed that all-trans retinoic acid (ATRA) suppresses the lung metastasis of SACC by correcting erroneous cell differentiation mainly caused by aberrant NOTCH1 or MYB expression. Bioinformatic, RNA-seq, and immunohistochemical (IHC) analyses of primary tissues and metastatic lung tissues from patients with SACC suggested that RA system insufficiency partially promotes lung metastasis. These findings imply the value of the RA system in diagnosis and treatment.

Clinical Insights into the Management of Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is aggressive hematologic malignancy derived from plasmacytoid dendritic cell precursors of myeloid cell lineage. Patients frequently present with bruise-like skin lesions, which typically are followed months later by progressive cytopenias. Historically, BPDCN prognosis has been dismal, with median overall survival ranging from 9 to 13 months. In the past 2 decades, our understanding of BPDCN pathogenesis has led to the successful development of novel therapeutics. In December 2018, the FDA approved tagraxofusp-erzs for adults and pediatric patients older than 2 years who have either treatment-naïve or relapsed/refractory BPDCN. Acute lymphoblastic leukemia (ALL)-based chemotherapy regimens also provide comparable outcomes to tagraxofusp. In our practice, for patients with good performance status, we use tagraxofusp, ALL-based chemotherapy regimens, or clinical trials as frontline induction therapy, followed by consolidation with allogeneic stem cell transplant once the first complete response has been achieved. Our induction regimen also includes intrathecal chemotherapy for central nervous system prophylaxis. Patients with poor performance status who are treatment-naïve or patients with relapsed/refractory disease have limited therapeutic options, and we strongly recommend enrollment in clinical trials; several novel agents and combinations are currently under clinical investigation for both treatment-naïve and relapsed/refractory BPDCN.

Development and Characterization of MYB-NFIB Fusion Expression in Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) is the second most common cancer type arising from the salivary gland. The frequent occurrence of chromosome t(6;9) translocation leading to the fusion of MYB and NFIB transcription factor genes is considered a genetic hallmark of ACC. This inter-chromosomal rearrangement may encode multiple variants of functional MYB-NFIB fusion in ACC. However, the lack of an ACC model that harbors the t(6;9) translocation has limited studies on defining the potential function and implication of chimeric MYB-NFIB protein in ACC. This report aims to establish a MYB-NFIB fusion protein expressing system in ACC cells for in vitro and in vivo studies. RNA-seq data from MYB-NFIB translocation positive ACC patients' tumors and MYB-NFIB fusion transcript in ACC patient-derived xenografts (ACCX) was analyzed to identify MYB breakpoints and their frequency of occurrence. Based on the MYB breakpoint identified, variants of MYB-NFIB fusion expression system were developed in a MYB-NFIB deficient ACC cell lines. Analysis confirmed MYB-NFIB fusion protein expression in ACC cells and ACCXs. Furthermore, recombinant MYB-NFIB fusion displayed sustained protein stability and impacted transcriptional activities of interferon-associated genes set as compared to a wild type MYB. In vivo tumor formation analysis indicated the capacity of MYB-NFIB fusion cells to grow as implanted tumors, although there were no fusion-mediated growth advantages. This expression system may be useful not only in studies to determine the functional aspects of MYB-NFIB fusion but also in evaluating effective drug response in vitro and in vivo settings.

Emerging Biomarkers for Early Detection of Chronic Kidney Disease

Chronic kidney disease (CKD) is a major and serious global health problem that leads to kidney damage as well as multiple systemic diseases. Early diagnosis and treatment are two major measures to prevent further deterioration of kidney function and to delay adverse outcomes. However, the paucity of early, predictive and noninvasive biomarkers has undermined our ability to promptly detect and treat this common clinical condition which affects more than 10% of the population worldwide. Despite all limitations, kidney function is still measured by serum creatinine, cystatin C, and albuminuria, as well as estimating glomerular filtration rate using different equations. This review aims to provide comprehensive insight into diagnostic methods available for early detection of CKD. In the review, we discuss the following topics: (i) markers of glomerular injury; (ii) markers of tubulointerstitial injury; (iii) the role of omics; (iv) the role of microbiota; (v) and finally, the role of microRNA in the early detection of CKD. Despite all novel findings, none of these biomarkers have met the criteria of an ideal early marker. Since the central role in CKD progression is the proximal tubule (PT), most data from the literature have analyzed biomarkers of PT injury, such as KIM-1 (kidney injury molecule-1), NGAL (neutrophil gelatinase-associated lipocalin), and L-FABP (liver fatty acid-binding protein).

Recent Advances on Immunohistochemistry and Molecular Biology for the Diagnosis of Adnexal Sweat Gland Tumors

Simple Summary

Cutaneous sweat gland tumors form an extremely diverse and heterogeneous group of neoplasms that show histological differentiation to the sweat apparatus. Due to their rarity, wide diagnostic range, and significant morphological overlap between entities, their accurate diagnosis remains challenging for pathologists. Until recently, little was known about the molecular pathogenesis of adnexal tumors. Recent findings have revealed a wide range of gene fusions and other oncogenic factors that can be used for diagnostic purposes and, for some, can be detected by immunohistochemistry. Among other organs containing exocrine glands, such as salivary glands, breasts, and bronchi, most of these biomarkers have been reported in homologous neoplasms that share morphological features with their cutaneous counterparts. This review aims to describe these recent molecular and immunohistochemical biomarkers in the field of sweat gland tumors.

Abstract

Cutaneous sweat gland tumors are a subset of adnexal neoplasms that derive or differentiate into the sweat apparatus. Their great diversity, rarity, and complex terminology make their pathological diagnosis challenging. Recent findings have revealed a wide spectrum of oncogenic drivers, several of which are of diagnostic interest for pathologists. Most of these molecular alterations are represented by gene fusions, which are shared with other homologous neoplasms occurring in organs containing exocrine glands, such as salivary and breast glands, which show similarities to the sweat apparatus. This review aims to provide a synthesis of the most recent immunohistochemical and molecular markers used for the diagnosis of sweat gland tumors and to highlight their relationship with similar tumors in other organs. It will cover adenoid cystic carcinoma (NFIB, MYB, and MYBL1 fusion), cutaneous mixed tumor (PLAG1 fusion), cylindroma and spiradenoma and their carcinomas thereof (NF-κB activation through CYLD inactivation or ALKP1 hotspot mutation), hidradenoma and hidradenocarcinoma (MAML2 fusion), myoepithelioma (EWSR1 and FUS fusion), poroma and porocarcinoma (YAP1, MAML2, and NUTM1 fusion), secretory carcinoma (ETV6, NTRK3 fusion), tubular adenoma and syringo-cystadenoma papilliferum (HRAS and BRAF activating mutations). Sweat gland tumors for which there are no known molecular abnormalities will also be briefly discussed, as well as potential future developments.

Bcr-TMP, a Novel Nanomolar-Active Compound That Exhibits Both MYB- and Microtubule-Inhibitory Activity

Simple Summary

Recent work has identified the transcription regulator MYB as an interesting therapeutic target for the treatment of certain leukemias and other cancers that are dependent on deregulated MYB activity, such as acute myeloid leukemia (AML) and adenoid cystic carcinoma (ACC). Here we report the identification and characterization of 2-amino-4-(3,4,5-trimethoxyphenyl)-4H-naphtho[1,2-b]pyran-3-carbonitrile (Bcr-TMP), a novel highly active MYB inhibitory compound. We show that nanomolar concentrations of Bcr-TMP are sufficient to down-regulate the expression of MYB target genes and induce both cell-death and differentiation in AML cell lines. Importantly, Bcr-TMP also and exerts stronger anti-proliferative effects on MYB-addicted primary AML cells and patient-derived ACC cells than on their non-oncogenic counterparts. Preliminary work shows that Bcr-TMP acts through p300, a protein interacting with MYB and stimulating its activity. Interestingly, Bcr-TMP has an additional activity as an anti-microtubule agent. Overall, Bcr-TMP is an interesting compound that warrants further research to understand its mechanism of action and its therapeutic potential for MYB-dependent malignancies.

Abstract

Studies of the role of MYB in human malignancies have highlighted MYB as a potential drug target for acute myeloid leukemia (AML) and adenoid cystic carcinoma (ACC). Here, we present the initial characterization of 2-amino-4-(3,4,5-trimethoxyphenyl)-4H-naphtho[1,2-b]pyran-3-carbonitrile (Bcr-TMP), a nanomolar-active MYB-inhibitory compound identified in a screen for novel MYB inhibitors. Bcr-TMP affects MYB function in a dual manner by inducing its degradation and suppressing its transactivation potential by disrupting its cooperation with co-activator p300. Bcr-TMP also interferes with the p300-dependent stimulation of C/EBPβ, a transcription factor co-operating with MYB in myeloid cells, indicating that Bcr-TMP is a p300-inhibitor. Bcr-TMP reduces the viability of AML cell lines at nanomolar concentrations and induces cell-death and expression of myeloid differentiation markers. It also down-regulates the expression of MYB target genes and exerts stronger anti-proliferative effects on MYB-addicted primary murine AML cells and patient-derived ACC cells than on their non-oncogenic counterparts. Surprisingly, we observed that Bcr-TMP also has microtubule-disrupting activity, pointing to a possible link between MYB-activity and microtubule stability. Overall, Bcr-TMP is a highly potent multifunctional MYB-inhibitory agent that warrants further investigation of its therapeutic potential and mechanism(s) of action.

Molecular Classification and Therapeutic Targets in Ependymoma

Ependymoma is a biologically diverse tumor wherein molecular classification has superseded traditional histological grading based on its superior ability to characterize behavior, prognosis, and possible targeted therapies. The current, updated molecular classification of ependymoma consists of ten distinct subgroups spread evenly among the spinal, infratentorial, and supratentorial compartments, each with its own distinct clinical and molecular characteristics. In this review, the history, histopathology, standard of care, prognosis, oncogenic drivers, and hypothesized molecular targets for all subgroups of ependymoma are explored. This review emphasizes that despite the varied behavior of the ependymoma subgroups, it remains clear that research must be performed to further elucidate molecular targets for these tumors. Although not all ependymoma subgroups are oncologically aggressive, development of targeted therapies is essential, particularly for cases where surgical resection is not an option without causing significant morbidity. The development of molecular therapies must rely on building upon our current understanding of ependymoma oncogenesis, as well as cultivating transfer of knowledge based on malignancies with similar genomic alterations.

A Detailed Gene Expression Map of Giardia Encystation

Giardia intestinalis is an intestinal protozoan parasite that causes diarrheal infections worldwide. A key process to sustain its chain of transmission is the formation of infectious cysts in the encystation process. We combined deep RNAseq of a broad range of encystation timepoints to produce a high-resolution gene expression map of Giardia encystation. This detailed transcriptomic map of encystation confirmed a gradual change of gene expression along the time course of encystation, showing the most significant gene expression changes during late encystation. Few genes are differentially expressed early in encystation, but the major cyst wall proteins CWP-1 and -2 are highly up-regulated already after 3.5 h encystation. Several transcription factors are sequentially up-regulated throughout the process, but many up-regulated genes at 7, 10, and 14 h post-induction of encystation have binding sites in the upstream regions for the Myb2 transcription factor, suggesting that Myb2 is a master regulator of encystation. We observed major changes in gene expression of several meiotic-related genes from 10.5 h of encystation to the cyst stage, and at 17.5 h encystation, there are changes in many different metabolic pathways and protein synthesis. Late encystation, 21 h to cysts, show extensive gene expression changes, most of all in VSP and HCMP genes, which are involved in antigenic variation, and genes involved in chromatin modifications. This high-resolution gene expression map of Giardia encystation will be an important tool in further studies of this important differentiation process.

From celiac disease to coccidia infection and vice-versa: The polyQ peptide CXCR3-interaction axis

Zonulin is a physiological modulator of intercellular tight junctions, which upregulation is involved in several diseases like celiac disease (CeD). The polyQ gliadin fragment binds to the CXCR3 chemokine receptor that activates zonulin upregulation, leading to increased intestinal permeability in humans. Here, we report a general hypothesis based on the structural connection between the polyQ sequence of the immunogenic CeD protein, gliadin, and enteric coccidian parasites proteins. Firstly, a novel interaction pathway between the parasites and the host is described based on the structural similarities between polyQ gliadin fragments and the parasite proteins. Secondly, a potential connection between coccidial infections as a novel environmental trigger of CeD is hypothesized. Therefore, this report represents a promising breakthrough for coccidian research and points out the potential role of coccidian parasites as a novel trigger of CeD that might define a preventive strategy for gluten-related disorders in general. Also see the video abstract here: https://youtu.be/oMaQasStcFI.

Fragment-Based Ligand Discovery Using Protein-Observed 19F NMR: A Second Semester Organic Chemistry CURE Project

Curriculum-based undergraduate research experiences (CUREs) have been shown to increase student retention in STEM fields and are starting to become more widely adopted in chemistry curricula. Here we describe a 10-week CURE that is suitable for a second-semester organic chemistry laboratory course. Students synthesize small molecules and use protein-observed ¹⁹F (PrOF) NMR to assess the small molecule's binding affinity to a target protein. The research project introduced students to multistep organic synthesis, structure-activity relationship studies, quantitative biophysical measurements (measuring K_d from PrOF NMR experiments), and scientific literacy. Docking experiments could be added to help students understand how changes in a ligand structure may affect binding to a protein. Assessment using the CURE survey indicates self-perceived skill gains from the course that exceed gains measured in a traditional and an inquiry-based laboratory experience. Given the speed of the binding experiment and the alignment of the synthetic methods with a second-semester organic chemistry laboratory course, a PrOF NMR fragment-based ligand discovery lab can be readily implemented in the undergraduate chemistry curriculum.

A study of deregulated MMR pathways and anticancer potential of curcuma derivatives using computational approach

Plant derived products have steadily gained momentum in treatment of cancer over the past decades. Curcuma and its derivatives, in particular, have diverse medicinal properties including anticancer potential with proven safety as supported by numerous in vivo and in vitro studies. A defective Mis-Match Repair (MMR) is implicated in solid tumors but its role in haematologic malignancies is not keenly studied and the current literature suggests that it is limited. Nonetheless, there are multiple pathways interjecting the mismatch repair proteins in haematologic cancers that may have a direct or indirect implication in progression of the disease. Here, through computational analysis, we target proteins that are involved in rewiring of multiple signaling cascades via altered expression in cancer using various curcuma derivatives (Curcuma longa L. and Curcuma caesia Roxb.) which in turn, profoundly controls MMR protein function. These biomolecules were screened to identify their efficacy on selected targets (in blood-related cancers); aberrations of which adversely impacted mismatch repair machinery. The study revealed that of the 536 compounds screened, six of them may have the potential to regulate the expression of identified targets and thus revive the MMR function preventing genomic instability. These results reveal that there may be potential plant derived biomolecules that may have anticancer properties against the tumors driven by deregulated MMR-pathways.

Molecular Pathology of Salivary Gland Neoplasms: Diagnostic, Prognostic, and Predictive Perspective

Salivary gland neoplasms are an uncommon and widely heterogeneous group of tumors. In recent years, there has been considerable progress in efforts to reveal the molecular landscape of these tumors, although it is still limited and appears to be only the tip of the iceberg. Genomic aberrations, especially specific chromosomal rearrangements including CRTC1-MAML2 and CRTC3-MAML2 in mucoepidermoid carcinoma, MYB-NFIB and MYBL1-NFIB fusions in adenoid cystic carcinoma, PLAG1 and HMGA2 alterations in pleomorphic adenoma and carcinoma ex pleomorphic adenoma, ETV6-NTRK3 and ETV6-RET in secretory carcinoma, EWSR1-ATF1 and EWSR1-CREM in clear cell carcinoma, provide new insights into the molecular pathogenesis of various salivary gland neoplasms and help to better classify them. These genetic aberrations primarily serve as diagnostic tools in salivary gland tumor diagnosis; however, some also have promise as prognostic or predictive biomarkers. This review summarizes the latest developments in molecular pathology of salivary gland tumors with a focus on distinctive molecular characteristics.

Overexpression of aberrant Wnt5a and its effect on acquisition of malignant phenotypes in adult T-cell leukemia/lymphoma (ATL) cells

Wnt5a is a ligand of the non-canonical Wnt signaling pathway involved in cell differentiation, motility, and inflammatory response. Adult T-cell leukemia/lymphoma (ATL) is one of the most aggressive T-cell malignancies caused by infection of human T-cell leukemia virus type1 (HTLV-1). Among subtypes of ATL, acute-type ATL cells are particularly resistant to current multidrug chemotherapies and show remarkably high cell-proliferative and invasive phenotypes. Here we show a dramatic increase of WNT5A gene expression in acute-type ATL cells compared with those of indolent-type ATL cells. Treatment with IWP-2 or Wnt5a-specific knockdown significantly suppressed cell growth of ATL-derived T-cell lines. We demonstrated that the overexpression of c-Myb and FoxM1 was responsible for the synergistic activation of the WNT5A promoter. Also, a WNT5A transcript variant without the exon4 (the ΔE4-WNT5A mRNA), encoding ΔC-Wnt5 (1-136aa of 380aa), is overexpressed in acute-type ATL cells. The ΔC-Wnt5a is secreted extracellularly and enhances cellular migration/invasion to a greater extent compared with wildtype (WT)-Wnt5a. Moreover, the ΔC-Wnt5a secretion was not suppressed by IWP-2, indicating that this mutant Wnt5a is secreted via a different pathway from the WT-Wnt5a. Taken together, synergistic overexpression of the ΔC-Wnt5a by c-Myb and FoxM1 may be responsible for the malignant phenotype of acute-type ATL cells.

Immune molecular profiling of a multiresistant primary prostate cancer with a neuroendocrine-like phenotype: a case report

Background

Understanding the drivers of recurrence in aggressive prostate cancer requires detailed molecular and genomic understanding in order to aid therapeutic interventions. We provide here a case report of histological, transcriptional, proteomic, immunological, and genomic features in a longitudinal study of multiple biopsies from diagnosis, through treatment, and subsequent recurrence.

Case presentation

Here we present a case study of a male in 70 s with high-grade clinically-localised acinar adenocarcinoma treated with definitive hormone therapy and radiotherapy. The patient progressed rapidly with rising PSA and succumbed without metastasis 52 months after diagnosis. We identified the expression of canonical histological markers of neuroendocrine PC (NEPC) including synaptophysin, neuron-specific enolase and thyroid transcription factor 1, as well as intact AR expression, in the recurrent disease only. The resistant disease was also marked by an extremely low immune infiltrate, extensive genomic chromosomal aberrations, and overactivity in molecular hallmarks of NEPC disease including Aurora kinase and E2F, as well as novel alterations in the cMYB pathway. We also observed that responses to both primary treatments (high dose-rate brachytherapy and androgen deprivation therapies) were consistent with known optimal responses—ruling out treatment inefficacy as a factor in relapse.

Conclusions

These data provide novel insights into a case of locally recurrent aggressive prostate cancer harbouring NEPC pathology, in the absence of detected metastasis.

Intramolecular interaction of B-MYB is regulated through Ser-577 phosphorylation

The transcription factor B-MYB is an important regulator of cell cycle-related processes that is activated by step-wise phosphorylation of multiple sites by cyclin-dependent kinases (CDKs) and conformational changes induced by the peptidylprolyl cis/trans isomerase Pin1. Here, we show that a conserved amino acid sequence around Ser-577 in the C-terminal part of B-MYB is able to interact with the B-MYB DNA-binding domain. Phosphorylation of Ser-577 disrupts this interaction and is regulated by the interplay of CDKs and the phosphatase CDC14B. Deletion of sequences surrounding Ser-577 hyperactivates the transactivation potential of B-MYB, decreases its proteolytic stability, and causes cell cycle defects. Overall, we show for the first time that B-MYB can undergo an intramolecular interaction that is controlled by the phosphorylation state of Ser-577.

Genetic hallmarks of recurrent/metastatic adenoid cystic carcinoma

BACKGROUNDAdenoid cystic carcinoma (ACC) is a rare malignancy arising in salivary glands and other sites, characterized by high rates of relapse and distant spread. Recurrent/metastatic (R/M) ACCs are generally incurable, due to a lack of active systemic therapies. To improve outcomes, deeper understanding of genetic alterations and vulnerabilities in R/M tumors is needed.METHODSAn integrated genomic analysis of 1,045 ACCs (177 primary, 868 R/M) was performed to identify alterations associated with advanced and metastatic tumors. Intratumoral genetic heterogeneity, germline mutations, and therapeutic actionability were assessed.RESULTSCompared with primary tumors, R/M tumors were enriched for alterations in key Notch (NOTCH1, 26.3% vs. 8.5%; NOTCH2, 4.6% vs. 2.3%; NOTCH3, 5.7% vs. 2.3%; NOTCH4, 3.6% vs. 0.6%) and chromatin-remodeling (KDM6A, 15.2% vs. 3.4%; KMT2C/MLL3, 14.3% vs. 4.0%; ARID1B, 14.1% vs. 4.0%) genes. TERT promoter mutations (13.1% of R/M cases) were mutually exclusive with both NOTCH1 mutations (q = 3.3 × 10-4) and MYB/MYBL1 fusions (q = 5.6 × 10-3), suggesting discrete, alternative mechanisms of tumorigenesis. This network of alterations defined 4 distinct ACC subgroups: MYB+NOTCH1+, MYB+/other, MYBWTNOTCH1+, and MYBWTTERT+. Despite low mutational load, we identified numerous samples with marked intratumoral genetic heterogeneity, including branching evolution across multiregion sequencing.CONCLUSIONThese observations collectively redefine the molecular underpinnings of ACC progression and identify further targets for precision therapies.FUNDINGAdenoid Cystic Carcinoma Research Foundation, Pershing Square Sohn Cancer Research grant, the PaineWebber Chair, Stand Up 2 Cancer, NIH R01 CA205426, the STARR Cancer Consortium, NCI R35 CA232097, the Frederick Adler Chair, Cycle for Survival, the Jayme Flowers Fund, The Sebastian Nativo Fund, NIH K08 DE024774 and R01 DE027738, and MSKCC through NIH/NCI Cancer Center Support Grant (P30 CA008748).

Cytogenetics of Blastic Plasmacytoid Dendritic Cell Neoplasm: Chromosomal Rearrangements and DNA Copy-Number Alterations

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a skin-tropic hematopoietic malignancy. Approximately 60% of cases with analyzable karyotyping results show complex karyotypes. Losses are more frequently found than copy-number gains. Recurrently deleted regions include tumor suppressor genes. No specific chromosomal abnormalities have been demonstrated in BPDCN, but genomic rearrangements involving the MYB family genes and MYC were identified. One-third of cases of BPDCN harbor the 8q24 rearrangement, most frequently with 6p21 harboring RUNX2, which is associated with immunoblastoid cytomorphology and MYC expression. MYB rearrangement is detected in 20% of patients with BPDCN. We review copy-number alterations and chromosomal rearrangements.

Prognostic value of connective tissue growth factor and c-Myb expression in IgA nephropathy and Henoch-Schönlein purpura-A pilot immunohistochemical study

AIM

Adverse and advanced prognostic signs in IgA nephropathy (IgAN) are interstitial fibrosis and tubular atrophy, but early predictors of bad outcome are still lacking. We investigated expression of connective tissue growth factor (CTGF) and c-Myb in renal biopsies of IgAN and Henoch-Schönlein purpura (HSP), because these gene products are indirectly included in fibrosis and epithelial-mesenchymal transition (EMT).

METHODS

The sample included 23 patients and 8 controls who underwent nephrectomy due to renal cancer. The slides cut from the paraffin blocks were prepared for standard indirect immunoflourescence, using antibodies to CTGF and c-Myb. Ten high-power non-overlapping fields were photographed on Olympus IX51 microscope. Average percent of positive tubular cells, as well as number of positive cells per glomerulus were calculated.

RESULTS

The cytoplasmic tubular CTGF expression was higher in IgAN/HSP than in controls (P < 0.001), whereas no difference was found in glomeruli (P = 0.437). The nuclear c-Myb expresssion in glomeruli and tubules was higher in IgAN/HSP than in controls (P < 0.05). In the follow-up, decline in renal function correlated with glomerular and tubular c-Myb, as well as tubular CTGF expression (all P < 0.05).

CONCLUSION

Our results proposed c-Myb and CTGF as novel, early and sensitive markers of chronic kidney disease and worse renal outcome, but larger series are needed.

Smed-myb-1 Specifies Early Temporal Identity during Planarian Epidermal Differentiation

The planarian epidermis provides an excellent model to explore adult stem cell (ASC) lineage development due to well-characterized and distinct spatiotemporal phases during lineage progression. Using flow cytometry-isolated cells enriched in epidermal progenitors, we performed transcriptional profiling and RNAi screening to uncover regulators of epidermal differentiation. We identified a MYB-type transcription factor (Smed-myb-1) required for the specification of the first temporal phase of post-mitotic maturation. Knockdown of myb-1 abolished the early progenitor phase of differentiation without ceasing production of subsequent epidermal progenitor states or homeostatic turnover and regeneration of the epidermis. Further examination revealed accelerated maturation of ASC descendants, with premature entry into subsequent progeny phases and, ultimately, the epidermis. These results demonstrate that a spatiotemporal shift in lineage progression occurs in the absence of the early progenitor state after myb-1 RNAi, and identify myb-1 as a critical regulator of the early temporal window in stepwise specification during planarian epidermal differentiation.

N-Terminal Truncated Myb with New Transcriptional Activity Produced Through Use of an Alternative MYB Promoter in Salivary Gland Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) is an aggressive salivary gland tumor that frequently displays perineural invasion and is often associated with translocations or overexpression of the MYB oncogene. Detailed analyses of MYB transcripts from ACC patient samples revealed that ACC tumors utilize an alternative MYB promoter, which is rarely used in normal cells or other tumor types. The alternative promoter transcripts produce N-terminally truncated Myb proteins lacking a highly conserved and phosphorylated domain, which includes the pS11 epitope that is frequently used to detect Myb proteins. In RNA-seq assays, Myb isoforms lacking the N-terminal domain displayed unique transcriptional activities, regulating many genes differently than full-length Myb. Thus, a regulatory pathway unique to ACC activates the alternative MYB promoter, leading to the production of a truncated Myb protein with altered transcriptional activities. This could provide new therapeutic opportunities for ACC patients.

Detecting MYB and MYBL1 fusion genes in tracheobronchial adenoid cystic carcinoma by targeted RNA-sequencing

Primary tracheobronchial adenoid cystic carcinoma is rare, accounting for less than 1% of all lung tumors. Many adenoid cystic carcinomas have been reported to have a specific chromosome translocation t(6;9)/MYB-NFIB. More recently, t(8;9)/MYBL1-NFIB gene fusion was reported in salivary gland adenoid cystic carcinomas which lacked a t(6;9)/MYB-NFIB. Two prior studies showed t(6;9)/MYB-NFIB in tracheobronchial adenoid cystic carcinoma; however, only rare cases of MYBL1 rearrangement have been reported in this carcinoma. In this study, we used targeted RNA sequencing to investigate fusion genes in tracheobronchial adenoid cystic carcinoma at our institution. Fusions of either MYB or MYBL1 genes were detected in 7 of 7 carcinomas. Three cases had MYB-NFIB, and 3 had MYBL1-NFIB. The remaining case showed a rare MYBL1-RAD51B fusion. These findings suggest that rearrangement involving MYB or MYBL1 is a hallmark of tracheobronchial adenoid cystic carcinoma.

Polymorphisms and genetic effects of PRLR, MOGAT1, MINPP1 and CHUK genes on milk fatty acid traits in Chinese Holstein

BACKGROUND

Our initial genome-wide association study (GWAS) identified 20 promising candidate genes for milk fatty acid (FA) traits in a Chinese Holstein population, including PRLR, MOGAT1, MINPP1 and CHUK genes. In this study, we performed whether they had significant genetic effects on milk FA traits in Chinese Holstein.

RESULTS

We re-sequenced the entire exons and 3000 bp of the 5' and 3' flanking regions, and identified 11 single nucleotide polymorphisms (SNPs), containing four in PRLR, two in MOGAT1, two in MINPP1, and three in CHUK. The SNP-based association analyses showed that all the 11 SNPs were significantly associated with at least one milk FA trait (P = 0.0456 ~ < 0.0001), and none of them had association with C11:0, C13:0, C15:0 and C16:0 (P > 0.05). By the linkage disequilibrium (LD) analyses, we found two, one, one, and one haplotype blocks in PRLR, MOGAT1, MINPP1, and CHUK, respectively, and each haplotype block was significantly associated with at least one milk FA trait (P = 0.0456 ~ < 0.0001). Further, g.38949011G > A in PRLR, and g.111599360A > G and g.111601747 T > A in MOGAT1 were predicted to alter the transcription factor binding sites (TFBSs). A missense mutation, g.39115344G > A, could change the PRLR protein structure. The g.20966385C > G of CHUK varied the binding sequences for microRNAs. Therefore, we deduced the five SNPs as the potential functional mutations.

CONCLUSION

In summary, we first detected the genetic effects of PRLR, MOGAT1, MINPP1 and CHUK genes on milk FA traits, and researched the potential functional mutations. These data provided the basis for further investigation on function validation of the four genes in Chinese Holstein.

c-Myb promotes growth and metastasis of colorectal cancer through c-fos-induced epithelial-mesenchymal transition

c-Myb is a crucial transcription factor that participates in various biological functions; however, its role in colorectal cancer (CRC) remains poorly investigated. We first analyzed the expression and clinical significance of c-Myb in a retrospective cohort enrolling 132 CRC patients. Then, the CRISPR/Cas9 technique was used to establish c-Myb gene KO CRC cell lines. Cellular functional assays in vitro and in vivo were used to evaluate the impact of c-Myb KO in CRC cells. Finally, RNA sequencing was used to investigate the potential oncogenic mechanisms regulated by c-Myb in CRC progression and related cellular validations were accordingly carried out. As a result, c-Myb is significantly overexpressed in CRC tissues as compared with adjacent normal tissues. High expression of c-Myb is positively correlated with lymph node metastasis and poor prognosis. Univariate analysis and multivariate analysis further identify c-Myb as an independent unfavorable prognostic factor for CRC patients. c-Myb KO inhibits the proliferation, apoptosis resistance, invasion, metastasis, colony formation and in vivo tumorigenesis of CRC cells. Also, the mechanism investigation indicates that c-Myb may promote CRC progression by regulating c-fos. c-fos overexpression can rescue the inhibitory effect of c-Myb KO on the malignant characteristics of CRC cells. Finally, we find that c-Myb KO inhibits the epithelial-mesenchymal transition (EMT) molecular phenotype in CRC cells, whereas c-fos overexpression can rescue this inhibitory effect. This study suggests that c-Myb promotes the malignant progression of CRC through c-fos-induced EMT and has the potential to be a promising prognostic biomarker and therapeutic target.

c-Myb and its Effector COX-2 as an Indicator Associated with Prognosis and Therapeutic Outcome in Colorectal Cancer

Background: One of our previous studies have demonstrated that the cancer suppressor miR-150 regulated the progression of colorectal cancer (CRC) by down-regulating v-myb avian myeloblastosis viral oncogene homolog (c-Myb). The purpose of present study was to evaluate the prognostic value of the expression of c-Myb and its effector, prostaglandin-endoperoxide synthase 2 (COX-2) in patients with CRC. Methods: We used tissue microarrays (containing 202 CRC tissues and matched adjacent normal tissues) and conducted immunohistochemical analysis and western blotting analysis (containing 3 CRC tissues and matched adjacent normal tissues) to detect the expression of c-Myb and COX-2. Results: Compared with the adjacent nontumorous tissues, both the expression levels of c-Myb and COX-2 were higher in the cancer tissues. A statistically significant correlation was found between the expression of c-Myb and COX-2. Elevated c-Myb and COX-2 were associated with more advanced tumor invasion and poorer overall survival by univariate analysis. Higher expression levels of both c-Myb and COX-2 were significantly associated with shorter overall survival for stage II and stage III patients with 5-Fu based chemotherapy. Multivariate analysis identified the lymph node involvement, distant metastatic spread and the elevated c-Myb and COX-2 as independent factors of poor prognosis for CRC. Conclusions: In conclusion, the overexpression of both c-Myb and COX-2 would be of prognostic screening value in patients with CRC.

Clinical value of combined detection of miR-1202 and miR-195 in early diagnosis of cervical cancer

The clinical value of the combined detection of miR-1202 and miR-195 in the early diagnosis of cervical cancer was studied. A retrospective analysis of 70 cervical cancer patients treated in the The Third Affiliated Hospital of Kunming Medical University and Yunnan Cancer Hospital from October 2015 to December 2017 was performed, and the lesion tissues were used as the experimental group. Normal cervical tissues from another 67 healthy females confirmed by physical examination at the same period were selected as the control group. The FIGO staging criteria were used for staging of the cervical cancer patients, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method was used for the detection of the expression of miR-1202 and miR-195 in different tissues, and the receiver operating curve (ROC) was used for the analysis of the application values of miR-1202 and miR-195 diagnosis alone and their combined diagnosis in early cervical cancer patients. The levels of miR-1202 and miR-195 in the experimental group were lower than those in the control group (P<0.05). The differences were significant in the different stages of cervical cancer tissues (P<0.05). The later the staging of cervical cancer tissues were, the lower the levels of miR-1202 and miR-195 were. The sensitivities and area under the curve (AUC) values of miR-1202 and miR-195 in the combined diagnosis of early cervical cancer were significantly higher than those of miR-1202 and miR-195 alone. The expression levels of miR-1202 and miR-195 in the cervical cancer patients are different in different stages. Guiding clinical treatment and prognosis according to the results of combined detection is beneficial for the development of treatment for cervical cancer patients and for prognostic judgement, worthy of popularization and application.

Activation of the oncogenic transcription factor B-Myb via multisite phosphorylation and prolyl cis/trans isomerization

The oncogenic transcription factor B-Myb is an essential regulator of late cell cycle genes whose activation by phosphorylation is still poorly understood. We describe a stepwise phosphorylation mechanism of B-Myb, which involves sequential phosphorylations mediated by cyclin-dependent kinase (Cdk) and Polo-like kinase 1 (Plk1) and Pin1-facilitated peptidyl-prolyl cis/trans isomerization. Our data suggest a model in which initial Cdk-dependent phosphorylation of B-Myb enables subsequent Pin1 binding and Pin1-induced conformational changes of B-Myb. This, in turn, initiates further phosphorylation of Cdk-phosphosites, enabling Plk1 docking and subsequent Plk1-mediated phosphorylation of B-Myb to finally allow B-Myb to stimulate transcription of late cell cycle genes. Our observations reveal novel mechanistic hierarchies of B-Myb phosphorylation and activation and uncover regulatory principles that might also apply to other Myb family members. Strikingly, overexpression of B-Myb and of factors mediating its activation strongly correlates with adverse prognoses for tumor patients, emphasizing B-Myb's role in tumorigenesis.

c-MYB and DMTF1 in Cancer

The c-Myb gene encodes a transcription factor that regulates cell proliferation, differentiation, and apoptosis through protein-protein interaction and transcriptional regulation of signaling pathways. The protein is frequently overexpressed in human leukemias, breast cancers, and other solid tumors suggesting that it is a bona fide oncogene. c-MYB is often overexpressed by translocation in human tumors with t(6;7)(q23;q34) resulting in c-MYB-TCRβ in T cell ALL, t(X;6)(p11;q23) with c-MYB-GATA1 in acute basophilic leukemia, and t(6;9)(q22-23;p23-24) with c-MYB-NF1B in adenoid cystic carcinoma. Antisense oligonucleotides to c-MYB were developed to purge bone marrow cells to eliminate tumor cells in leukemias. Recently, small molecules that inhibit c-MYB activity have been developed to disrupt its interaction with p300. The Dmp1 (cyclin D binding myb-like protein 1; Dmtf1) gene was isolated through its virtue for binding to cyclin D2. It is a transcription factor that has a Myb-like repeat for DNA binding. The Dmtf1 protein directly binds to the Arf promoter for transactivation and physically interacts with p53 to activate the p53 pathway. The gene is hemizygously deleted in 35-42% of human cancers and is associated with longer survival. The significances of aberrant expression of c-MYB and DMTF1 proteins in human cancers and their clinical significances are discussed.

A novel cell-based screening assay for small-molecule MYB inhibitors identifies podophyllotoxins teniposide and etoposide as inhibitors of MYB activity

The transcription factor MYB plays key roles in hematopoietic cells and has been implicated the development of leukemia. MYB has therefore emerged as an attractive target for drug development. Recent work has suggested that targeting MYB by small-molecule inhibitors is feasible and that inhibition of MYB has potential as a therapeutic approach against acute myeloid leukemia. To facilitate the identification of small-molecule MYB inhibitors we have re-designed and improved a previously established cell-based screening assay and have employed it to screen a natural product library for potential inhibitors. Our work shows that teniposide and etoposide, chemotherapeutic agents causing DNA-damage by inhibiting topoisomerase II, potently inhibit MYB activity and induce degradation of MYB in AML cell lines. MYB inhibition is suppressed by caffeine, suggesting that MYB is inhibited indirectly via DNA-damage signalling. Importantly, ectopic expression of an activated version of MYB in pro-myelocytic NB4 cells diminished the anti-proliferative effects of teniposide, suggesting that podophyllotoxins disrupt the proliferation of leukemia cells not simply by inducing general DNA-damage but that their anti-proliferative effects are boosted by inhibition of MYB. Teniposide and etoposide therefore act like double-edged swords that might be particularly effective to inhibit tumor cells with deregulated MYB.

MYB - A regulatory factor in hematopoiesis

MYB is a transcription factor which was identified in birds as a viral oncogene (v-MYB). Its cellular counterpart was subsequently isolated as c-MYB which has three functional domains - DNA binding domain, transactivation domain and negative regulatory domain. c-MYB is essential for survival, and deletion of both alleles of the gene results in embryonic death. It is highly expressed in hematopoietic cells, thymus and neural tissue, and required for T and B lymphocyte development and erythroid maturation. Additionally, aberrant MYB expression has been found in numerous solid cancer cells and human leukemia. Recent studies have also implicated c-MYB in the regulation of expression of fetal hemoglobin which is highly beneficial to the β-hemoglobinopathies (beta thalassemia and sickle cell disease). These findings suggest that MYB could be a potential therapeutic target in leukemia, and possibly also a target for therapeutic increase of fetal hemoglobin in the β-hemoglobinopathies.

MYB induces the expression of the oncogenic corepressor SKI in acute myeloid leukemia

Acute myeloid leukemia (AML) arises through clonal expansion of transformed myeloid progenitor cells. The SKI proto-oncogene is highly upregulated in different solid tumors and leukemic cells, but little is known about its transcriptional regulation during leukemogenesis. MYB is an important hematopoietic transcription factor involved in proliferation as well as differentiation and upregulated in most human acute leukemias. Here, we find that MYB protein binds within the regulatory region of the SKI gene in AML cells. Reporter gene assays using MYB binding sites present in the SKI gene locus show MYB-dependent transcriptional activation. SiRNA-mediated depletion of MYB in leukemic cell lines reveals that MYB is crucial for SKI gene expression. Consistently, we observed a positive correlation of MYB and SKI expression in leukemic cell lines and in samples of AML patients. Moreover, MYB and SKI both were downregulated by treatment with histone deacetylase inhibitors. Strikingly, differentiation of AML cells induced by depletion of MYB is attenuated by overexpression of SKI. Our findings identify SKI as a novel MYB target gene, relevant for the MYB-induced differentiation block in leukemic cells.

Cutaneous Adnexal Cylindroma of Breast: Epithelial Immunoreactivities for GATA-3, Mammaglobin, and E-Cadherin Do Not Equate to a Mammary Ductal Neoplasm

Cylindromas are benign epithelial neoplasms derived from cutaneous eccrine adnexal structures. These tumors are most commonly encountered on the head, neck, and scalp of older women. In rare instances, solitary cylindromas may arise at other body sites. In the current case, a cylindroma of the skin of the breast was diagnosed by complete excision. Immunohistochemical studies confirmed the tumor cells to be immunoreactive with cytokeratin AE1/3, cytokeratin 5/6, cytokeratin 7, p63, and SOX10. The neoplastic cells were also noted to be immunoreactive with markers typically expected to be positive in ductal epithelium of the breast including GATA3, mammaglobin, and E-cadherin. The case emphasizes the importance of correlating clinical setting, imaging studies, patient history, and careful microscopic evaluation in arriving at an accurate diagnosis. This case also illustrates the point that not all “breast” tumors that are confirmed to be positive for GATA3, mammaglobin, and E-cadherin are derived from mammary ducts.

Reassessing the Potential of Myb-targeted Anti-cancer Therapy

Transcription factor MYB is essential for the tumorigenesis of multiple cancers, especially leukemia, breast cancer, colon cancer, adenoid cystic carcinoma and brain cancer. Thus, MYB has been regarded as an attractive target for tumor therapy. However, pioneer studies of antisense oligodeoxynucleotides against MYB, which were launched three decades ago in leukemia therapy, were discontinued because of their unsatisfactory clinical outcomes. In recent years, the roles of MYB in tumor transformation have become increasingly clear. Moreover, the regulatory mechanisms of MYB, such as the vital effects of MYB co-regulators on MYB activity and of transcriptional elongation on MYB expression, have been unveiled. These observations have underpinned novel approaches in inhibiting MYB. This review discusses the structure, function and regulation of MYB, focusing on recent insights into MYB-associated oncogenesis and how MYB-targeted therapeutics can be explored. Additionally, the main MYB-targeted therapies, including novel genetic therapy, RNA interference, microRNAs and low-molecular-weight compounds, which are especially promising inhibitors that target MYB co-regulators and transcriptional elongation, are described, and their prospects are assessed.

Transcriptomes define distinct subgroups of salivary gland adenoid cystic carcinoma with different driver mutations and outcomes

The relative rarity of salivary gland adenoid cystic carcinoma (ACC) and its slow growing yet aggressive nature has complicated the development of molecular markers for patient stratification. To analyze molecular differences linked to the protracted disease course of ACC and metastases that form 5 or more years after diagnosis, detailed RNA-sequencing (RNA-seq) analysis was performed on 68 ACC tumor samples, starting with archived, formalin-fixed paraffin-embedded (FFPE) samples up to 25 years old, so that clinical outcomes were available. A statistical peak-finding approach was used to classify the tumors that expressed MYB or MYBL1, which had overlapping gene expression signatures, from a group that expressed neither oncogene and displayed a unique phenotype. Expression of MYB or MYBL1 was closely correlated to the expression of the SOX4 and EN1 genes, suggesting that they are direct targets of Myb proteins in ACC tumors. Unsupervised hierarchical clustering identified a subgroup of approximately 20% of patients with exceptionally poor overall survival (median less than 30 months) and a unique gene expression signature resembling embryonic stem cells. The results provide a strategy for stratifying ACC patients and identifying the high-risk, poor-outcome group that are candidates for personalized therapies.

Optimized approach for Ion Proton RNA sequencing reveals details of RNA splicing and editing features of the transcriptome

RNA-sequencing (RNA-seq) has become the standard method for unbiased analysis of gene expression but also provides access to more complex transcriptome features, including alternative RNA splicing, RNA editing, and even detection of fusion transcripts formed through chromosomal translocations. However, differences in library methods can adversely affect the ability to recover these different types of transcriptome data. For example, some methods have bias for one end of transcripts or rely on low-efficiency steps that limit the complexity of the resulting library, making detection of rare transcripts less likely. We tested several commonly used methods of RNA-seq library preparation and found vast differences in the detection of advanced transcriptome features, such as alternatively spliced isoforms and RNA editing sites. By comparing several different protocols available for the Ion Proton sequencer and by utilizing detailed bioinformatics analysis tools, we were able to develop an optimized random primer based RNA-seq technique that is reliable at uncovering rare transcript isoforms and RNA editing features, as well as fusion reads from oncogenic chromosome rearrangements. The combination of optimized libraries and rapid Ion Proton sequencing provides a powerful platform for the transcriptome analysis of research and clinical samples.

Human germ/stem cell-specific gene TEX19 influences cancer cell proliferation and cancer prognosis

Background

Cancer/testis (CT) genes have expression normally restricted to the testis, but become activated during oncogenesis, so they have excellent potential as cancer-specific biomarkers. Evidence is starting to emerge to indicate that they also provide function(s) in the oncogenic programme. Human TEX19 is a recently identified CT gene, but a functional role for TEX19 in cancer has not yet been defined.

Methods

siRNA was used to deplete TEX19 levels in various cancer cell lines. This was extended using shRNA to deplete TEX19 in vivo. Western blotting, fluorescence activated cell sorting and immunofluorescence were used to study the effect of TEX19 depletion in cancer cells and to localize TEX19 in normal testis and cancer cells/tissues. RT-qPCR and RNA sequencing were employed to determine the changes to the transcriptome of cancer cells depleted for TEX19 and Kaplan-Meier plots were generated to explore the relationship between TEX19 expression and prognosis for a range of cancer types.

Results

Depletion of TEX19 levels in a range of cancer cell lines in vitro and in vivo restricts cellular proliferation/self-renewal/reduces tumour volume, indicating TEX19 is required for cancer cell proliferative/self-renewal potential. Analysis of cells depleted for TEX19 indicates they enter a quiescent-like state and have subtle defects in S-phase progression. TEX19 is present in both the nucleus and cytoplasm in both cancerous cells and normal testis. In cancer cells, localization switches in a context-dependent fashion. Transcriptome analysis of TEX19 depleted cells reveals altered transcript levels of a number of cancer-/proliferation-associated genes, suggesting that TEX19 could control oncogenic proliferation via a transcript/transcription regulation pathway. Finally, overall survival analysis of high verses low TEX19 expressing tumours indicates that TEX19 expression is linked to prognostic outcomes in different tumour types.

Conclusions

TEX19 is required to drive cell proliferation in a range of cancer cell types, possibly mediated via an oncogenic transcript regulation mechanism. TEX19 expression is linked to a poor prognosis for some cancers and collectively these findings indicate that not only can TEX19 expression serve as a novel cancer biomarker, but may also offer a cancer-specific therapeutic target with broad spectrum potential.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0653-4) contains supplementary material, which is available to authorized users.

O-Linked N-Acetylglucosamine (O-GlcNAc) Expression Levels Epigenetically Regulate Colon Cancer Tumorigenesis by Affecting the Cancer Stem Cell Compartment via Modulating Expression of Transcriptional Factor MYBL1

To study the regulation of colorectal adenocarcinoma progression by O-GlcNAc, we have focused on the O-GlcNAc-mediated epigenetic regulation of human colon cancer stem cells (CCSC). Xenograft tumors from colon tumor cells with O-linked N-acetylglucosamine transferase (OGT) knockdown grew significantly slower than those formed from control cells, indicating a reduced proliferation of tumor cells due to inhibition of OGT expression. Significant reduction of the CCSC population was observed in the tumor cells after OGT knockdown, whereas tumor cells treated with the O-GlcNAcase inhibitor showed an increased CCSC population, indicating that O-GlcNAc levels regulated the CCSC compartment. When grown in suspension, tumor cells with OGT knockdown showed a reduced ability to form tumorspheres, indicating a reduced self-renewal of CCSC due to reduced levels of O-GlcNAc. ChIP-sequencing experiments using an anti-O-GlcNAc antibody revealed significant chromatin enrichment of O-GlcNAc-modified proteins at the promoter of the transcription factor MYBL1, which was also characterized by the presence of H3K27me3. RNA-sequencing analysis showed an increased expression of MYBL1 in tumor cells with OGT knockdown. Forced overexpression of MYBL1 led to a reduced population of CCSC and tumor growth in vivo, similar to the effects of OGT silencing. Moreover, two CpG islands near the transcription start site of MYBL1 were identified, and O-GlcNAc levels regulated their methylation status. These results strongly argue that O-GlcNAc epigenetically regulates MYBL1, functioning similarly to H3K27me3. The aberrant CCSC compartment observed after modulating O-GlcNAc levels is therefore likely to result, at least in part, from the epigenetic regulation of MYBL1 expression by O-GlcNAc, thereby significantly affecting tumor progression.