MYBPH inhibits NM IIA assembly via direct interaction with NMHC IIA and reduces cell motility

Non-Muscle Myosin II A: Friend or Foe in Cancer?

Non-muscle myosin IIA (NM IIA) is a motor protein that belongs to the myosin II family. The myosin heavy chain 9 (MYH9) gene encodes the heavy chain of NM IIA. NM IIA is a hexamer and contains three pairs of peptides, which include the dimer of heavy chains, essential light chains, and regulatory light chains. NM IIA is a part of the actomyosin complex that generates mechanical force and tension to carry out essential cellular functions, including adhesion, cytokinesis, migration, and the maintenance of cell shape and polarity. These functions are regulated via light and heavy chain phosphorylation at different amino acid residues. Apart from physiological functions, NM IIA is also linked to the development of cancer and genetic and neurological disorders. MYH9 gene mutations result in the development of several autosomal dominant disorders, such as May-Hegglin anomaly (MHA) and Epstein syndrome (EPS). Multiple studies have reported NM IIA as a tumor suppressor in melanoma and head and neck squamous cell carcinoma; however, studies also indicate that NM IIA is a critical player in promoting tumorigenesis, chemoradiotherapy resistance, and stemness. The ROCK-NM IIA pathway regulates cellular movement and shape via the control of cytoskeletal dynamics. In addition, the ROCK-NM IIA pathway is dysregulated in various solid tumors and leukemia. Currently, there are very few compounds targeting NM IIA, and most of these compounds are still being studied in preclinical models. This review provides comprehensive evidence highlighting the dual role of NM IIA in multiple cancer types and summarizes the signaling networks involved in tumorigenesis. Furthermore, we also discuss the role of NM IIA as a potential therapeutic target with a focus on the ROCK-NM IIA pathway.

Structure, regulation, and mechanisms of nonmuscle myosin-2

Members of the myosin superfamily of molecular motors are large mechanochemical ATPases that are implicated in an ever-expanding array of cellular functions. This review focuses on mammalian nonmuscle myosin-2 (NM2) paralogs, ubiquitous members of the myosin-2 family of filament-forming motors. Through the conversion of chemical energy into mechanical work, NM2 paralogs remodel and shape cells and tissues. This process is tightly controlled in time and space by numerous synergetic regulation mechanisms to meet cellular demands. We review how recent advances in structural biology together with elegant biophysical and cell biological approaches have contributed to our understanding of the shared and unique mechanisms of NM2 paralogs as they relate to their kinetics, regulation, assembly, and cellular function.

HBXIP blocks myosin-IIA assembly by phosphorylating and interacting with NMHC-IIA in breast cancer metastasis

Tumor metastasis depends on the dynamic balance of the actomyosin cytoskeleton. As a key component of actomyosin filaments, non-muscle myosin-IIA disassembly contributes to tumor cell spreading and migration. However, its regulatory mechanism in tumor migration and invasion is poorly understood. Here, we found that oncoprotein hepatitis B X-interacting protein (HBXIP) blocked the myosin-IIA assemble state promoting breast cancer cell migration. Mechanistically, mass spectrometry analysis, co-immunoprecipitation assay and GST-pull down assay proved that HBXIP directly interacted with the assembly-competent domain (ACD) of non-muscle heavy chain myosin-IIA (NMHC-IIA). The interaction was enhanced by NMHC-IIA S1916 phosphorylation via HBXIP-recruited protein kinase PKCβII. Moreover, HBXIP induced the transcription of PRKCB, encoding PKCβII, by coactivating Sp1, and triggered PKCβII kinase activity. Interestingly, RNA sequencing and mouse metastasis model indicated that the anti-hyperlipidemic drug bezafibrate (BZF) suppressed breast cancer metastasis via inhibiting PKCβII-mediated NMHC-IIA phosphorylation in vitro and in vivo. We reveal a novel mechanism by which HBXIP promotes myosin-IIA disassembly via interacting and phosphorylating NMHC-IIA, and BZF can serve as an effective anti-metastatic drug in breast cancer.

An mRNA characterization model predicting survival in patients with invasive breast cancer based on The Cancer Genome Atlas database

BACKGROUND

Invasive breast cancer is a highly heterogeneous tumor, although there have been many prediction methods for invasive breast cancer risk prediction, the prediction effect is not satisfactory. There is an urgent need to develop a more accurate method to predict the prognosis of patients with invasive breast cancer.

OBJECTIVE

To identify potential mRNAs and construct risk prediction models for invasive breast cancer based on bioinformaticsMETHODS: In this study, we investigated the differences in mRNA expression profiles between invasive breast cancer and normal breast samples, and constructed a risk model for the prediction of prognosis of invasive breast cancer with univariate and multivariate Cox analyses.

RESULTS

We constructed a risk model comprising 8 mRNAs (PAX7, ZIC2, APOA5, TP53AIP1,MYBPH, USP41, DACT2, and POU3F2) for the prediction of invasive breast cancer prognosis. We used the 8-mRNA risk prediction model to divide 1076 samples into high-risk groups and low-risk groups, the Kaplan-Meier curve showed that the high-risk group was closely related to the poor prognosis of overall survival in patients with invasive breast cancer. The receiver operating characteristic curve revealed an area under the curve of 0.773 for the 8 mRNA model at 3-year overall survival, indicating that this model showed good specificity and sensitivity for prediction of prognosis of invasive breast cancer.

CONCLUSIONS

The study provides an effective bioinformatic analysis for the better understanding of the molecular pathogenesis and prognosis risk assessment of invasive breast cancer.

Molecular signatures of beef tenderness: Underlying mechanisms based on integromics of protein biomarkers from multi-platform proteomics studies

Over the last two decades, proteomics have been employed to decipher the underlying factors contributing to variation in the quality of muscle foods, including beef tenderness. One such approach is the application of high-throughput protein analytical platforms in the identification of meat quality biomarkers. To broaden our understanding about the biological mechanisms underpinning meat tenderization across a large number of studies, an integromics study was performed to review the current status of protein biomarker discovery targeting beef tenderness. This meta-analysis is the first to gather and propose a comprehensive list of 124 putative protein biomarkers derived from 28 independent proteomics-based experiments, from which 33 robust candidates were identified worthy of evaluation using targeted or untargeted data-independent acquisition proteomic methods. We further provide an overview of the interconnectedness of the main biological pathways impacting tenderness determination after multistep analyses including Gene Ontology annotations, pathway and process enrichment and literature mining, and specifically discuss the major proteins and pathways most often reported in proteomics research.

Achievements in Cancer Research and its Therapeutics in Hundred Years

Cancer research has progressed leaps and bounds over the years. This review is a brief overview of the cancer research, milestone achievements and therapeutic studies on it over the one hundred ten years which would give us an insight into how far we have come to understand and combat this fatal disease leading to millions of deaths worldwide. Modern biology has proved that cancer is a very complex disease as still we do not know precisely how it triggers. It involves several factors such as protooncogene, oncogene, kinase, tumor suppressor gene, growth factor, signalling cascade, micro RNA, immunity, environmental factors and carcinogens. However, modern technology now helps the cancer patient on the basis of acquired and established knowledge in the last hundred years to save human lives.

Nonmuscle myosin IIA and IIB differentially modulate migration and alter gene expression in primary mouse tumorigenic cells

Though many cancers are known to show up-regulation of nonmuscle myosin (NM) IIA and IIB, the mechanism by which NMIIs aid in cancer development remains unexplored. Here we demonstrate that tumor-generating, fibroblast-like cells isolated from 3-methylcholanthrene (3MC)-induced murine tumor exhibit distinct phospho-dependent localization of NMIIA and NMIIB at the perinuclear area and tip of the filopodia and affect cell migration differentially. While NMIIA-KD affects protrusion dynamics and increases cell directionality, NMIIB-KD lowers migration speed and increases filopodial branching. Strategically located NMIIs at the perinuclear area colocalize with the linker of nucleoskeleton and cytoskeleton (LINC) protein Nesprin2 and maintain the integrity of the nuclear-actin cap. Interestingly, knockdown of NMIIs results in altered expression of genes involved in epithelial-to-mesenchymal transition, angiogenesis, and cellular senescence. NMIIB-KD cells display down-regulation of Gsc and Serpinb2, which is strikingly similar to Nesprin2-KD cells as assessed by quantitative PCR analysis. Further gene network analysis predicts that NMIIA and NMIIB may act on similar pathways but through different regulators. Concomitantly, knockdown of NMIIA or NMIIB lowers the growth rate and tumor volume of 3MC-induced tumor in vivo. Altogether, these results open a new window to further investigate the effect of LINC-associated perinuclear actomyosin complex on mechanoresponsive gene expression in the growing tumor.

MYH9 overexpression correlates with clinicopathological parameters and poor prognosis of epithelial ovarian cancer

The aim of the present study was to investigate the expression of myosin 9 (MYH9) in epithelial ovarian cancer and to explore its correlation with the clinicopathological parameters and prognosis of epithelial ovarian cancer (EOC). A total of 265 cases of paraffin-embedded ovarian cancer tissues and 41 paratumor tissues which had been pathologically confirmed at the Memorial Hospital of Sun Yat-sen University from 2009 to 2017 were included in the present study. MYH9 expression was investigated with immunohistochemistry using a polyclonal antibody specific for MYH9. MYH9 expression is associated with disease progression free and overall survival in epithelial ovarian cancer patients; and the expression of MYH9 is associated with International Federation of Gynecology and Obstetrics stage, lymph node metastasis, intraperitoneal metastasis, survival status (at last follow-up), intraperitoneal recurrence, residual tumor size and ascites with tumor cells. Moreover, in a multivariate model MYH9 overexpression was an independent predictor of poor survival in epithelial ovarian cancer. MYH9 may be a candidate that plays a oncogenic role in epithelial ovarian cancer. MYH9 is a useful independent prognostic marker in epithelial ovarian cancer, and it may provide a candidate target therapy treatment of ovarian cancer in the future.

Myosin Heavy Chain 9: Oncogene or Tumor Suppressor Gene?

MYH9 was first discovered due to thrombocytopenia caused by MYH9 mutation-related abnormalities. In recent years, researchers have increasingly found that MYH9 plays an important role in cancer as a cytokine involved in cytoskeletal reorganization, cellular pseudopodia formation, and migration. MYH9 is closely related to the progress and poor prognosis of most solid tumors, and it is now accepted that MYH9 is a suppressor gene and plays an important role on the re-Rho pathway. Recent research has been limited to the study of tissues. However, it would be more direct and informative to be able to use hematology to assess tumor prognosis and changes in MYH9 levels and NMMHC-IIA. This article summarizes recent research on MYH9 and provides a reference for future clinical research.

MYH9 Promotes Growth and Metastasis via Activation of MAPK/AKT Signaling in Colorectal Cancer

The contractile protein MYH9 (non-muscle myosin IIA) is an actin-binding protein that plays a fundamental role in cell adhesion, migration, and division. However, its distinct role in colorectal cancer (CRC) still remains unidentified. In this study, we detected significant MYH9 overexpression in CRC samples compared with paired normal tissues using western blotting and tissue microarray immunohistochemistry (IHC). Moreover, analysis of patient clinical information demonstrated that MYH9 overexpression was strongly correlated with lymph node metastasis and poor overall survival. Endogenous overexpression of MYH9 enhanced the ability of cell proliferation and migration in vitro, and accelerated CRC growth in mouse models. Silencing of MYH9 revealed repressive effects on CRC cells in vitro and in vivo. Furthermore, primary biomechanics that involved MAPK/AKT signaling mediated epithelial-mesenchymal transition (EMT) was uncovered underlying MYH9 dependent cell behaviors. Collectively, our data showed that MYH9 significantly promoted tumorigenesis by regulating MAPK/AKT signaling, and was remarkably correlated with poor prognosis in CRC. MYH9 may thus be a novel biomarker and drug target in the diagnosis and treatment of CRC.

MYH9: Structure, functions and role of non-muscle myosin IIA in human disease

The MYH9 gene encodes the heavy chain of non-muscle myosin IIA, a widely expressed cytoplasmic myosin that participates in a variety of processes requiring the generation of intracellular chemomechanical force and translocation of the actin cytoskeleton. Non-muscle myosin IIA functions are regulated by phosphorylation of its 20 kDa light chain, of the heavy chain, and by interactions with other proteins. Variants of MYH9 cause an autosomal-dominant disorder, termed MYH9-related disease, and may be involved in other conditions, such as chronic kidney disease, non-syndromic deafness, and cancer. This review discusses the structure of the MYH9 gene and its protein, as well as the regulation and physiologic functions of non-muscle myosin IIA with particular reference to embryonic development. Moreover, the review focuses on current knowledge about the role of MYH9 variants in human disease.

Myosins as fundamental components during tumorigenesis: diverse and indispensable

Myosin is a kind of actin-based motor protein. As the crucial functions of myosin during tumorigenesis have become increasingly apparent, the profile of myosin in the field of cancer research has also been growing. Eighteen distinct classes of myosins have been discovered in the past twenty years and constitute a diverse superfamily. Various myosins share similar structures. They all convert energy from ATP hydrolysis to exert mechanical stress upon interactions with microfilaments. Ongoing research is increasingly suggesting that at least seven kinds of myosins participate in the formation and development of cancer. Myosins play essential roles in cytokinesis failure, chromosomal and centrosomal amplification, multipolar spindle formation and DNA microsatellite instability. These are all prerequisites of tumor formation. Subsequently, myosins activate various processes of tumor invasion and metastasis development including cell migration, adhesion, protrusion formation, loss of cell polarity and suppression of apoptosis. In this review, we summarize the current understanding of the roles of myosins during tumorigenesis and discuss the factors and mechanisms which may regulate myosins in tumor progression. Furthermore, we put forward a completely new concept of “chromomyosin” to demonstrate the pivotal functions of myosins during karyokinesis and how this acts to optimize the functions of the members of the myosin superfamily.

MYBPH inhibits vascular smooth muscle cell migration and attenuates neointimal hyperplasia in a rat carotid balloon-injury model

Vascular smooth muscle cell (VSMC) migration is implicated in restenosis. Myosin binding protein H (MYBPH) is capable of reducing cell motility and metastasis. In this study, we sought to determine whether MYBPH is involved in VSMC migration and neointima formation in response to vascular injury. To determine the expression of MYBPH in injured artery, we used a standard rat carotid artery balloon-injury model. In vivo studies have demonstrated that MYBPH is upregulated after vascular injury. VSMCs treated with platelet-derived growth factor (PDGF)-BB displayed increased MYBPH mRNA and protein levels. PDGF-induced VSMC migration was inhibited by adenovirus-mediated expression of MYBPH whereas it was enhanced by small interfering RNA knockdown of MYBPH. The activation of ROCK1 was repressed by MYBPH. Luminal delivery of MYBPH adenovirus to carotid arteries decreased neointimal hyperplasia in vivo. MYBPH may, therefore, serve as a novel therapeutic target for postangioplasty restenosis.

Experimental Modeling Supports a Role for MyBP-HL as a Novel Myofilament Component in Arrhythmia and Dilated Cardiomyopathy

BACKGROUND

Cardiomyopathy and arrhythmias are under significant genetic influence. Here, we studied a family with dilated cardiomyopathy and associated conduction system disease in whom prior clinical cardiac gene panel testing was unrevealing.

METHODS

Whole-genome sequencing and induced pluripotent stem cells were used to examine a family with dilated cardiomyopathy and atrial and ventricular arrhythmias. We also characterized a mouse model with heterozygous and homozygous deletion of Mybphl.

RESULTS

Whole-genome sequencing identified a premature stop codon, R255X, in the MYBPHL gene encoding MyBP-HL (myosin-binding protein-H like), a novel member of the myosin-binding protein family. MYBPHL was found to have high atrial expression with low ventricular expression. We determined that MyBP-HL protein was myofilament associated in the atria, and truncated MyBP-HL protein failed to incorporate into the myofilament. Human cell modeling demonstrated reduced expression from the mutant MYBPHL allele. Echocardiography of Mybphl heterozygous and null mouse hearts exhibited a 36% reduction in fractional shortening and an increased diastolic ventricular chamber size. Atria weight normalized to total heart weight was significantly increased in Mybphl heterozygous and null mice. Using a reporter system, we detected robust expression of Mybphl in the atria, and in discrete puncta throughout the right ventricular wall and septum, as well. Telemetric electrocardiogram recordings in Mybphl mice revealed cardiac conduction system abnormalities with aberrant atrioventricular conduction and an increased rate of arrhythmia in heterozygous and null mice.

CONCLUSIONS

The findings of reduced ventricular function and conduction system defects in Mybphl mice support that MYBPHL truncations may increase risk for human arrhythmias and cardiomyopathy.

The heavy chain has its day: regulation of myosin-II assembly

Nonmuscle myosin-II is an actin-based motor that converts chemical energy into force and movement, and thus functions as a key regulator of the eukaryotic cytoskeleton. Although it is established that phosphorylation on the regulatory light chain increases the actin-activated MgATPase activity of the motor and promotes myosin-II filament assembly, studies have begun to characterize alternative mechanisms that regulate filament assembly and disassembly. These investigations have revealed that all three nonmuscle myosin-II isoforms are subject to additional regulatory controls, which impact diverse cellular processes. In this review, we discuss current knowledge on mechanisms that regulate the oligomerization state of nonmuscle myosin-II filaments by targeting the myosin heavy chain.

Life without double-headed non-muscle myosin II motor proteins

Non-muscle myosin II motor proteins (myosin IIA, myosin IIB, and myosin IIC) belong to a class of molecular motor proteins that are known to transduce cellular free-energy into biological work more efficiently than man-made combustion engines. Nature has given a single myosin II motor protein for lower eukaryotes and multiple for mammals but none for plants in order to provide impetus for their life. These specialized nanomachines drive cellular activities necessary for embryogenesis, organogenesis, and immunity. However, these multifunctional myosin II motor proteins are believed to go awry due to unknown reasons and contribute for the onset and progression of many autosomal-dominant disorders, cataract, deafness, infertility, cancer, kidney, neuronal, and inflammatory diseases. Many pathogens like HIV, Dengue, hepatitis C, and Lymphoma viruses as well as Salmonella and Mycobacteria are now known to take hostage of these dedicated myosin II motor proteins for their efficient pathogenesis. Even after four decades since their discovery, we still have a limited knowledge of how these motor proteins drive cell migration and cytokinesis. We need to enrich our current knowledge on these fundamental cellular processes and develop novel therapeutic strategies to fix mutated myosin II motor proteins in pathological conditions. This is the time to think how to relieve the hijacked myosins from pathogens in order to provide a renewed impetus for patients' life. Understanding how to steer these molecular motors in proliferating and differentiating stem cells will improve stem cell based-therapeutics development. Given the plethora of cellular activities non-muscle myosin motor proteins are involved in, their importance is apparent for human life.

Genome-wide identification of AR-regulated genes translated in Sertoli cells in vivo using the RiboTag approach

An understanding of the molecular mechanisms by which androgens drive spermatogenesis has been thwarted by the fact that few consistent androgen receptor (AR) target genes have been identified. Here, we addressed this issue using next-generation sequencing coupled with the RiboTag approach, which purifies translated mRNAs expressed in cells that express cyclic recombinase (CRE). Using RiboTag mice expressing CRE in Sertoli cells (SCs), we identified genes expressed specifically in SCs in both prepubertal and adult mice. Unexpectedly, this analysis revealed that the SC-specific gene program is already largely defined at the initiation of spermatogenesis despite the subsequent dramatic maturational changes known to occur in SCs. To identify AR-regulated genes, we generated triple-mutant mice in which the SCs express the RiboTag but lack ARs. RNA sequencing analysis revealed hundreds of SC-expressed AR-regulated genes that had previously gone unnoticed, including suppressed genes involved in ovarian development. Comparison of the SC-enriched dataset with that from the whole testes allowed us to classify genes in terms of their degree of expression in SCs. This revealed that a greater fraction of AR-up-regulated genes than AR-down-regulated genes were expressed predominantly in SCs. Our results also revealed that AR signaling in SCs causes a large number of genes not detectably expressed in SCs to undergo altered expression, thereby providing genome-wide evidence for wide-scale communication between SCs and other cells. Taken together, our results identified novel classes of genes expressed in a hormone-dependent manner in different testicular cell subsets and highlight a new approach to analyze cell type-specific gene regulation.

High-throughput screen identifies disulfiram as a potential therapeutic for triple-negative breast cancer cells: interaction with IQ motif-containing factors

Triple-negative breast cancer (TNBC) represents an aggressive subtype, for which radiation and chemotherapy are the only options. Here we describe the identification of disulfiram, an FDA-approved drug used to treat alcoholism, as well as the related compound thiram, as the most potent growth inhibitors following high-throughput screens of 3185 compounds against multiple TNBC cell lines. The average IC₅₀ for disulfiram was ~300 nM. Drug affinity responsive target stability (DARTS) analysis identified IQ motif-containing factors IQGAP1 and MYH9 as direct binding targets of disulfiram. Indeed, knockdown of these factors reduced, though did not completely abolish, cell growth. Combination treatment with 4 different drugs commonly used to treat TNBC revealed that disulfiram synergizes most effectively with doxorubicin to inhibit cell growth of TNBC cells. Disulfiram and doxorubicin cooperated to induce cell death as well as cellular senescence, and targeted the ESA⁺/CD24^-/low/CD44⁺ cancer stem cell population. Our results suggest that disulfiram may be repurposed to treat TNBC in combination with doxorubicin.

NKX2-1/TTF-1: an enigmatic oncogene that functions as a double-edged sword for cancer cell survival and progression

Emerging evidence indicates that NKX2-1, a homeobox-containing transcription factor also known as TTF-1, plays a role as a "lineage-survival" oncogene in lung adenocarcinomas. In T cell acute lymphoblastic leukemia, gene rearrangements lead to aberrant expression of NKX2-1/TTF-1. Despite accumulating evidence supporting its oncogenic role, it has become apparent that NKX2-1/TTF-1 expression also has biological and clinical functions in the opposite direction that act against tumor progression. Herein, we review recent findings showing these enigmatic double-edged characteristics, with special attention given to the roles of NKX2-1/TTF-1 in lung development and carcinogenesis.