TGFbeta influences Myc, Miz-1 and Smad to control the CDK inhibitor p15INK4b

DYRK1A-TGF-β signaling axis determines sensitivity to OXPHOS inhibition in hepatocellular carcinoma

Intervening in mitochondrial oxidative phosphorylation (OXPHOS) has emerged as a potential therapeutic strategy for certain types of cancers. Employing kinome-based CRISPR screen, we find that knockout of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) synergizes with OXPHOS inhibitor IACS-010759 in liver cancer cells. Targeting DYRK1A combined with OXPHOS inhibitors activates TGF-β signaling, which is crucial for OXPHOS-inhibition-triggered cell death. Mechanistically, upregulation of glutamine transporter solute carrier family 1 member 5 (SLC1A5) transcription compensates for the increased glutamine requirement upon OXPHOS inhibition. DYRK1A directly phosphorylates SMAD3 Thr132, thereby suppressing the negative impact of TGF-β signaling on transcription of SLC1A5, leading to intrinsic resistance of liver cancer cells to OXPHOS inhibition. Moreover, we demonstrate the therapeutic efficacy of IACS-010759 in combination with DYRK1A inhibition in multiple liver cancer models, including xenografts, patient-derived xenografts, and spontaneous tumor model. Our study elucidates how the DYRK1A-TGF-β signaling axis controls the response of tumor cells to OXPHOS inhibition and provides valuable insights into targeting OXPHOS for liver cancer therapy.

Cell cycle checkpoint factor p15Ink4b is a novel regulator of osteoclast differentiation

Osteoclasts are specialized cells essential for bone resorption, a crucial process in bone remodeling, and dysregulation of osteoclastogenesis can lead to pathological bone loss such as osteoporosis and rheumatoid arthritis. Therefore, understanding the precise mechanisms governing osteoclast differentiation is crucial for developing effective therapies for skeletal diseases. In osteoclastogenesis, as well as other differentiated cells, it is well understood that cell cycle arrest is essential for terminal differentiation and is tightly regulated by CDK inhibitors such as Cip/Kip family and Ink4 family protein. In this manuscript, we identified p15Ink4b, a member of the Ink4 family, as a novel regulator of osteoclastogenesis by comprehensive single-cell RNA sequence data reanalyzing. Furthermore, histological analysis and in vitro osteoclast differentiation assay revealed that p15Ink4b functionally regulates osteoclastogenesis. Our findings may not only provide insights into the molecular mechanisms of osteoclast differentiation but also underscore the potential of harnessing cell cycle mechanisms to develop novel therapeutic strategies for bone diseases.

Loss of SMAD1 in acute myeloid leukemia with KMT2A::AFF1 and KMT2A::MLLT3 fusion genes

Introduction

KMT2A-rearrangements define a subclass of acute leukemias characterized by a distinct gene expression signature linked to the dysfunctional oncogenic fusion proteins arising from various chromosomal translocations involving the KMT2A (also known as MLL1) gene. Research on the disease pathomechanism in KMT2A-rearranged acute leukemias has mainly focused on the upregulation of the stemness-related genes of the HOX-family and their co-factor MEIS1.

Results

Here we report the KMT2A::AFF1 and KMT2A::MLLT3 fusion gene-dependent downregulation of SMAD1, a TGF-β signaling axis transcription factor. SMAD1 expression is lost in the majority of AML patient samples and cell lines containing the two fusion genes KMT2A::AFF1 and KMT2A::MLLT3 compared to non-rearranged controls. Loss of SMAD1 expression is inducible by introducing the respective two KMT2A fusion genes into hematopoietic stem and progenitor cells. The loss of SMAD1 correlated with a markedly reduced amount of H3K4me3 levels at the SMAD1 promoter in tested cells with KMT2A::AFF1 and KMT2A::MLLT3. The expression of SMAD1 in cells with KMT2A::AFF1 fusion genes impacted the growth of cells in vitro and influenced engraftment of the KMT2A::AFF1 cell line MV4-11 in vivo. In MV4-11 cells SMAD1 expression caused a downregulation of HOXA9 and MEIS1, which was reinforced by TGF-β stimulation. Moreover, in MV4-11 cells SMAD1 presence sensitized cells for TGF-β mediated G1-arrest.

Conclusion

Overall, our data contributes to the understanding of the role of TGF-β signaling in acute myeloid leukemia with KMT2A::AFF1 by showing that SMAD1 loss can influence the growth dynamics and contribute to the pathogenic expression of disease driving factors.

NFAT5 governs cellular plasticity-driven resistance to KRAS-targeted therapy in pancreatic cancer

Resistance to KRAS therapy in pancreatic ductal adenocarcinoma (PDAC) involves cellular plasticity, particularly the epithelial-to-mesenchymal transition (EMT), which poses challenges for effective targeting. Chronic pancreatitis, a known risk factor for PDAC, elevates TGFβ levels in the tumor microenvironment (TME), promoting resistance to KRAS therapy. Mechanistically, TGFβ induces the formation of a novel protein complex composed of SMAD3, SMAD4, and the nuclear factor NFAT5, triggering EMT and resistance by activating key mediators such as S100A4. Inhibiting NFAT5 attenuates pancreatitis-induced resistance to KRAS inhibition and extends mouse survival. Additionally, TGFβ stimulates PDAC cells to secrete CCL2, recruiting macrophages that contribute to KRAS bypass through paracrine S100A4. Our findings elucidate the role of TGFβ signaling in EMT-associated KRAS therapy resistance and identify NFAT5 as a druggable target. Targeting NFAT5 could disrupt this regulatory network, offering a potential avenue for preventing resistance in PDAC.

Colorectal cancer cell dormancy: An insight into pathways

Cancer cell dormancy (CCD) in colorectal cancer (CRC) poses a significant challenge to effective treatment. In CRC, CCD contributes to tumour recurrence, drug resistance, and amplifying the disease's burden. The molecular mechanisms governing CCD and strategies for eliminating dormant cancer cells remain largely unexplored. Therefore, understanding the molecular mechanisms governing dormancy is crucial for improving patient outcomes and developing targeted therapies. This editorial highlights the complex interplay of signalling pathways and factors involved in colorectal CCD, emphasizing the roles of Hippo/YAP, pluripotent transcription factors such as NANOG, HIF-1α signalling, and Notch signalling pathways. Additionally, ERK/p38α/β/MAPK pathways, AKT signalling pathway, and Extracellular Matrix Metalloproteinase Inducer, along with some potential less explored pathways such as STAT/p53 switch and canonical and non-canonical Wnt and SMAD signalling, are also involved in promoting colorectal CCD. Highlighting their clinical significance, these findings may offer the potential for identifying key dormancy regulator pathways, improving treatment strategies, surmounting drug resistance, and advancing personalized medicine approaches. Moreover, insights into dormancy mechanisms could lead to the development of predictive biomarkers for identifying patients at risk of recurrence and the tailoring of targeted therapies based on individual dormancy profiles. It is essential to conduct further research into these pathways and their modulation to fully comprehend CRC dormancy mechanisms and enhance patient outcomes.

E-Cadherin Induces Serine Synthesis to Support Progression and Metastasis of Breast Cancer

The loss of E-cadherin, an epithelial cell adhesion molecule, has been implicated in metastasis by mediating the epithelial-mesenchymal transition, which promotes invasion and migration of cancer cells. However, recent studies have demonstrated that E-cadherin supports the survival and proliferation of metastatic cancer cells. Here, we identified a metabolic role for E-cadherin in breast cancer by upregulating the de novo serine synthesis pathway (SSP). The upregulated SSP provided metabolic precursors for biosynthesis and resistance to oxidative stress, enabling E-cadherin+ breast cancer cells to achieve faster tumor growth and enhanced metastases. Inhibition of phosphoglycerate dehydrogenase, a rate-limiting enzyme in the SSP, significantly and specifically hampered proliferation of E-cadherin+ breast cancer cells and rendered them vulnerable to oxidative stress, inhibiting their metastatic potential. These findings reveal that E-cadherin reprograms cellular metabolism, promoting tumor growth and metastasis of breast cancers. Significance: E-Cadherin promotes the progression and metastasis of breast cancer by upregulating the de novo serine synthesis pathway, offering promising targets for inhibiting tumor growth and metastasis in E-cadherin-expressing tumors.

Structure, unique biological properties, and mechanisms of action of transforming growth factor β

Transforming growth factor β (TGF-β) is a ubiquitous molecule that is extremely conserved structurally and plays a systemic role in human organism. TGF-β is a homodimeric molecule consisting of two subunits joined through a disulphide bond. In mammals, three genes code for TGF-β1, TGF-β2, and TGF-β3 isoforms of this cytokine with a dominating expression of TGF-β1. Virtually, all normal cells contain TGF-β and its specific receptors. Considering the exceptional role of fine balance played by the TGF-β in anumber of physiological and pathological processes in human body, this cytokine may be proposed for use in medicine as an immunosuppressant in transplantology, wound healing and bone repair. TGFb itself is an important target in oncology. Strategies for blocking members of TGF-β signaling pathway as therapeutic targets have been considered. In this review, signalling mechanisms of TGF-β1 action are addressed, and their role in physiology and pathology with main focus on carcinogenesis are described.

Modeling complex age-related eye disease

Modeling complex eye diseases like age-related macular degeneration (AMD) and glaucoma poses significant challenges, since these conditions depend highly on age-related changes that occur over several decades, with many contributing factors remaining unknown. Although both diseases exhibit a relatively high heritability of >50%, a large proportion of individuals carrying AMD- or glaucoma-associated genetic risk variants will never develop these diseases. Furthermore, several environmental and lifestyle factors contribute to and modulate the pathogenesis and progression of AMD and glaucoma. Several strategies replicate the impact of genetic risk variants, pathobiological pathways and environmental and lifestyle factors in AMD and glaucoma in mice and other species. In this review we will primarily discuss the most commonly available mouse models, which have and will likely continue to improve our understanding of the pathobiology of age-related eye diseases. Uncertainties persist whether small animal models can truly recapitulate disease progression and vision loss in patients, raising doubts regarding their usefulness when testing novel gene or drug therapies. We will elaborate on concerns that relate to shorter lifespan, body size and allometries, lack of macula and a true lamina cribrosa, as well as absence and sequence disparities of certain genes and differences in their chromosomal location in mice. Since biological, rather than chronological, age likely predisposes an organism for both glaucoma and AMD, more rapidly aging organisms like small rodents may open up possibilities that will make research of these diseases more timely and financially feasible. On the other hand, due to the above-mentioned anatomical and physiological features, as well as pharmacokinetic and -dynamic differences small animal models are not ideal to study the natural progression of vision loss or the efficacy and safety of novel therapies. In this context, we will also discuss the advantages and pitfalls of alternative models that include larger species, such as non-human primates and rabbits, patient-derived retinal organoids, and human organ donor eyes.

Characterization of cell cycle, inflammation, and oxidative stress signaling role in non-communicable diseases: Insights into genetic variants, microRNAs and pathways

Non-Communicable Diseases (NCDs) significantly impact global health, contributing to over 70% of premature deaths, as reported by the World Health Organization (WHO). These diseases have complex and multifactorial origins, involving genetic, epigenetic, environmental and lifestyle factors. While Genome-Wide Association Study (GWAS) is widely recognized as a valuable tool for identifying variants associated with complex phenotypes; the multifactorial nature of NCDs necessitates a more comprehensive exploration, encompassing not only the genetic but also the epigenetic aspect. For this purpose, we employed a bioinformatics-multiomics approach to examine the genetic and epigenetic characteristics of NCDs (i.e. colorectal cancer, coronary atherosclerosis, squamous cell lung cancer, psoriasis, type 2 diabetes, and multiple sclerosis), aiming to identify novel biomarkers for diagnosis and prognosis. Leveraging GWAS summary statistics, we pinpointed Single Nucleotide Polymorphisms (SNPs) independently associated with each NCD. Subsequently, we identified genes linked to cell cycle, inflammation and oxidative stress mechanisms, revealing shared genes across multiple diseases, suggesting common functional pathways. From an epigenetic perspective, we identified microRNAs (miRNAs) with regulatory functions targeting these genes of interest. Our findings underscore critical genetic pathways implicated in these diseases. In colorectal cancer, the dysregulation of the "Cytokine Signaling in Immune System" pathway, involving LAMA5 and SMAD7, regulated by Hsa-miR-21-5p, Hsa-miR-103a-3p, and Hsa-miR-195-5p, emerged as pivotal. In coronary atherosclerosis, the pathway associated with "binding of TCF/LEF:CTNNB1 to target gene promoters" displayed noteworthy implications, with the MYC factor controlled by Hsa-miR-16-5p as a potential regulatory factor. Squamous cell lung carcinoma analysis revealed significant pathways such as "PTK6 promotes HIF1A stabilization," regulated by Hsa-let-7b-5p. In psoriasis, the "Endosomal/Vacuolar pathway," involving HLA-C and Hsa-miR-148a-3p and Hsa-miR-148b-3p, was identified as crucial. Type 2 Diabetes implicated the "Regulation of TP53 Expression" pathway, controlled by Hsa-miR-106a-5p and Hsa-miR-106b-5p. In conclusion, our study elucidates the genetic framework and molecular mechanisms underlying NCDs, offering crucial insights into potential genetic/epigenetic biomarkers for diagnosis and prognosis. The specificity of pathways and related miRNAs in different pathologies highlights promising candidates for further clinical validation, with the potential to advance personalized treatments and alleviate the global burden of NCDs.

Advances and Challenges in Targeting TGF-β Isoforms for Therapeutic Intervention of Cancer: A Mechanism-Based Perspective

The TGF-β family is a group of 25 kDa secretory cytokines, in mammals consisting of three dimeric isoforms (TGF-βs 1, 2, and 3), each encoded on a separate gene with unique regulatory elements. Each isoform plays unique, diverse, and pivotal roles in cell growth, survival, immune response, and differentiation. However, many researchers in the TGF-β field often mistakenly assume a uniform functionality among all three isoforms. Although TGF-βs are essential for normal development and many cellular and physiological processes, their dysregulated expression contributes significantly to various diseases. Notably, they drive conditions like fibrosis and tumor metastasis/progression. To counter these pathologies, extensive efforts have been directed towards targeting TGF-βs, resulting in the development of a range of TGF-β inhibitors. Despite some clinical success, these agents have yet to reach their full potential in the treatment of cancers. A significant challenge rests in effectively targeting TGF-βs' pathological functions while preserving their physiological roles. Many existing approaches collectively target all three isoforms, failing to target just the specific deregulated ones. Additionally, most strategies tackle the entire TGF-β signaling pathway instead of focusing on disease-specific components or preferentially targeting tumors. This review gives a unique historical overview of the TGF-β field often missed in other reviews and provides a current landscape of TGF-β research, emphasizing isoform-specific functions and disease implications. The review then delves into ongoing therapeutic strategies in cancer, stressing the need for more tools that target specific isoforms and disease-related pathway components, advocating mechanism-based and refined approaches to enhance the effectiveness of TGF-β-targeted cancer therapies.

Molecular insights into gastric cancer: The impact of TGFBR2 and hsa-mir-107 revealed by microarray sequencing and bioinformatics

BACKGROUND

Gastric carcinoma (GC) remains a significant therapeutic challenge, garnering widespread attention. Oxymatrine (OMT), an active component of the traditional Chinese medicine compound Kushen injection (CKI), has shown promising results in combination with chemotherapy for the treatment of GC. However, the molecular mechanisms underlying OMT's therapeutic effects in GC have yet to be elucidated.

METHODS

The transcriptomic expression data of HGC-27 post-OMT intervention were obtained through microarray sequencing, while the miRNA and mRNA sequencing data for GC patients were sourced from the TCGA database. The mechanism of OMT intervention in GC is analyzed in multiple aspects, including Protein-Protein Interactions (PPI), Competitive Endogenous RNA (ceRNA) networks, correlation and co-expression analyses, immune infiltration, and clinical implications.

RESULTS

By analyzing key modules, five critical mRNAs were identified, and their interacting miRNAs were predicted to construct a ceRNA network. Among these, TGFBR2 and hsa-miR-107 have correlations or co-expression relationships with other genes in the network. They are differentially expressed in most other cancers, associated with prognosis, and have diagnostic value. TGFBR2 also exhibits immune infiltration phenomena, and its high expression is linked to poor patient prognosis. Low expression of hsa-miR-107 is associated with poor patient prognosis. OMT may act on the TGFβ/Smad signaling pathway or negatively regulate the WNT signaling pathway through the hsa-miR-107/BTRC axis, thereby inhibiting the onset and progression of GC.

CONCLUSION

The mechanisms of OMT intervention in GC are diverse, TGFBR2 and hsa-miR-107 may serve as prognostic molecular biomarkers or potential therapeutic targets.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

METTL3 promotes cellular senescence of colorectal cancer via modulation of CDKN2B transcription and mRNA stability

Cellular senescence plays a critical role in cancer development, but the underlying mechanisms remain poorly understood. Our recent study uncovered that replicative senescent colorectal cancer (CRC) cells exhibit increased levels of mRNA N6-methyladenosine (m6A) and methyltransferase METTL3. Knockdown of METTL3 can restore the senescence-associated secretory phenotype (SASP) of CRC cells. Our findings, which were confirmed by m6A-sequencing and functional studies, demonstrate that the cyclin-dependent kinase inhibitor 2B (CDKN2B, encoding p15INK4B) is a mediator of METTL3-regulated CRC senescence. Specifically, m6A modification at position A413 in the coding sequence (CDS) of CDKN2B positively regulates its mRNA stability by recruiting IGF2BP3 and preventing binding with the CCR4-NOT complex. Moreover, increased METTL3 methylates and stabilizes the mRNA of E2F1, which binds to the -208 to -198 regions of the CDKN2B promoter to facilitate transcription. Inhibition of METTL3 or specifically targeting CDKN2B methylation can suppress CRC senescence. Finally, the METTL3/CDKN2B axis-induced senescence can facilitate M2 macrophage polarization and is correlated with aging and CRC progression. The involvement of METTL3/CDKN2B in cell senescence provides a new potential therapeutic target for CRC treatment and expands our understanding of mRNA methylation's role in cellular senescence.

NIPBL::NACC1 Fusion Hepatic Carcinoma

Several reports describing a rare primary liver tumor with histologic features reminiscent of follicular thyroid neoplasms have been published under a variety of descriptive terms including thyroid-like, solid tubulocystic, and cholangioblastic cholangiocarcinoma. Although these tumors are considered to represent histologic variants, they lack classic features of cholangiocarcinoma and have unique characteristics, namely immunoreactivity for inhibin and NIPBL::NACC1 fusions. The purpose of this study is to present clinicopathologic and molecular data for a large series of these tumors to better understand their pathogenesis. We identified 11 hepatic tumors with these features. Immunohistochemical and NACC1 and NIPBL fluorescence in situ hybridization assays were performed on all cases. Four cases had available material for whole-genome sequencing (WGS) analysis. Most patients were adult women (mean age: 42 y) who presented with abdominal pain and large hepatic masses (mean size: 14 cm). Ten patients had no known liver disease. Of the patients with follow-up information, 3/9 (33%) pursued aggressive behavior. All tumors were composed of bland cuboidal cells with follicular and solid/trabecular growth patterns in various combinations, were immunoreactive for inhibin, showed albumin mRNA by in situ hybridization, and harbored the NIPBL::NACC1 fusion by fluorescence in situ hybridization. WGS corroborated the presence of the fusion in all 4 tested cases, high tumor mutational burden in 2 cases, and over 30 structural variants per case in 3 sequenced tumors. The cases lacked mutations typical of conventional intrahepatic cholangiocarcinoma. In this report, we describe the largest series of primary inhibin-positive hepatic neoplasms harboring a NIPBL::NACC1 fusion and the first WGS analysis of these tumors. We propose to name this neoplasm NIPBL:NACC1 fusion hepatic carcinoma.

Multifaceted TGF-β signaling, a master regulator: From bench-to-bedside, intricacies, and complexities

Physiological embryogenesis and adult tissue homeostasis are regulated by transforming growth factor-β (TGF-β), an evolutionarily conserved family of secreted polypeptide factors, acting in an autocrine and paracrine manner. The role of TGF-β in inflammation, fibrosis, and cancer is complex and sometimes even contradictory, exhibiting either inhibitory or promoting effects depending on the stage of the disease. Under pathological conditions, especially fibrosis and cancer, overexpressed TGF-β causes extracellular matrix deposition, epithelial-mesenchymal transition, cancer-associated fibroblast formation, and/or angiogenesis. In this review article, we have tried to dive deep into the mechanism of action of TGF-β in inflammation, fibrosis, and carcinogenesis. As TGF-β and its downstream signaling mechanism are implicated in fibrosis and carcinogenesis blocking this signaling mechanism appears to be a promising avenue. However, targeting TGF-β carries substantial risk as this pathway is implicated in multiple homeostatic processes and is also known to have tumor-suppressor functions. There is a need for careful dosing of TGF-β drugs for therapeutic use and patient selection.

AHSA1 Regulates Hepatocellular Carcinoma Progression via the TGF-β/Akt-Cyclin D1/CDK6 Pathway

Background

Activator of heat shock protein 90 (HSP90) ATPase Activity 1 (AHSA1) regulates proliferation, apoptosis, migration, and invasion of osteosarcoma and hepatocellular carcinoma (HCC). However, the novel mechanism of AHSA1 in the tumor biology of hepatocellular carcinoma (HCC) remains unclear.

Methods

We analyzed AHSA1 expression in 85 pairs of clinical samples of HCC and the Cancer Genome Atlas database. The role of AHSA1 in HCC was proved by cell proliferation, colony formation, migration, cell cycle analysis in vitro, xenograft models and tumor metastasis assay in vivo, and bioinformatics.

Results

High AHSA1 expression was demonstrated in HCC and associated with invasive depth, clinical stage, and poor overall survival of patients. Univariate Cox analysis confirmed that AHSA1 was an independent prognostic factor for patients with HCC. Meanwhile, AHSA1 upregulation promoted cell proliferation, colony formation, and cell migration in vitro and tumor cell proliferation and metastasis of HCC cells in vivo. AHSA1 upregulation increased the cell cycle transition from G1 to S phase by increasing the expression of cyclinD1, cyclinD3, and cyclin-dependent kinase 6(CD). Transforming growth factor beta 1 (TGF-β1)-induced protein kinase B (Akt) signaling regulated the expression of downstream targets, including cyclinD1. AHSA1 expression was closely correlated with the expression of TGF-β, Akt, cyclinD1, cyclinD3, and CDK6 using the Gene Expression Profiling Interactive Analysis database. AHSA1 upregulation participated in HCC progression by regulating TGF-β/Akt-cyclinD1/CDK6 signaling.

Conclusion

AHSA1 might serve as a biomarker for predicting the clinical outcome of patients with HCC. It is vital in tumor metastasis and disease progression of HCC and may facilitate the development of clinical intervention strategies against HCC.

A cell cycle centric view of tumour dormancy

Tumour dormancy and recurrent metastatic cancer remain the greatest clinical challenge for cancer patients. Dormant tumour cells can evade treatment and detection, while retaining proliferative potential, often for years, before relapsing to tumour outgrowth. Cellular quiescence is one mechanism that promotes and maintains tumour dormancy due to its central role in reducing proliferation, elevating cyto-protective mechanisms, and retaining proliferative potential. Quiescence/proliferation decisions are dictated by intrinsic and extrinsic signals, which regulate the activity of cyclin-dependent kinases (CDKs) to modulate cell cycle gene expression. By clarifying the pathways regulating CDK activity and the signals which activate them, we can better understand how cancer cells enter, maintain, and escape from quiescence throughout the progression of dormancy and metastatic disease. Here we review how CDK activity is regulated to modulate cellular quiescence in the context of tumour dormancy and highlight the therapeutic challenges and opportunities it presents.

MYC function and regulation in physiological perspective

MYC, a key member of the Myc-proto-oncogene family, is a universal transcription amplifier that regulates almost every physiological process in a cell including cell cycle, proliferation, metabolism, differentiation, and apoptosis. MYC interacts with several cofactors, chromatin modifiers, and regulators to direct gene expression. MYC levels are tightly regulated, and deregulation of MYC has been associated with numerous diseases including cancer. Understanding the comprehensive biology of MYC under physiological conditions is an utmost necessity to demark biological functions of MYC from its pathological functions. Here we review the recent advances in biological mechanisms, functions, and regulation of MYC. We also emphasize the role of MYC as a global transcription amplifier.

Regulation of the somatotropic axis by MYC-mediated miRNA repression

The transcription factor MYC is overexpressed in many human cancers and has a significant causal role in tumor incidence and progression. In contrast, Myc +/- heterozygous mice, which have decreased MYC expression, exhibit a 10-20% increase in lifespan and a decreased incidence or progression of several age-related diseases. Myc heterozygous mice were also reported to have decreased mTOR and IGF1 signaling, two pathways whose reduced activity is associated with longevity in diverse species. Given MYC's downstream role in these pathways, the downregulation of mTOR and IGF1 signaling in Myc heterozygotes suggests the presence of feedback loops within this regulatory network. In this communication we provide further evidence that the reduction of Myc expression in Myc +/- heterozygous mice provokes a female-specific decrease in circulating IGF1 as well as a reduction of IGF1 protein in the liver. In particular, reduced Myc expression led to upregulation of miRNAs that target the Igf1 transcript, thereby inhibiting its translation and leading to decreased IGF1 protein levels. Using Argonaute (AGO)-CLIP-sequencing we found enrichment of AGO binding in the Igf1 transcript at the target sites of let-7, miR-122, and miR-29 in female, but not male Myc heterozygotes. Upregulation of the liver-specific miR-122 in primary hepatocytes in culture and in vivo in mice resulted in significant downregulation of IGF1 protein, but not mRNA. Reduced levels of IGF1 increased GH production in the pituitary through a well-documented negative-feedback relationship. In line with this, we found that IGF1 levels in bone (where miR-122 is not expressed) were unchanged, consistent with the decreased incidence of osteoporosis in female Myc heterozygotes, despite decreased circulating IGF1.

BRD4 and MYC: power couple in transcription and disease

The MYC proto-oncogene and BRD4, a BET family protein, are two cardinal proteins that have a broad influence in cell biology and disease. Both proteins are expressed ubiquitously in mammalian cells and play central roles in controlling growth, development, stress responses and metabolic function. As chromatin and transcriptional regulators, they play a critical role in regulating the expression of a burgeoning array of genes, maintaining chromatin architecture and genome stability. Consequently, impairment of their function or regulation leads to many diseases, with cancer being the most predominant. Interestingly, accumulating evidence indicates that regulation of the expression and functions of MYC are tightly intertwined with BRD4 at both transcriptional and post-transcriptional levels. Here, we review the mechanisms by which MYC and BRD4 are regulated, their functions in governing various molecular mechanisms and the consequences of their dysregulation that lead to disease. We present a perspective of how the regulatory mechanisms for the two proteins could be entwined at multiple points in a BRD4-MYC nexus that leads to the modulation of their functions and disease upon dysregulation.

TGF-β signaling in health and disease

The TGF-β regulatory system plays crucial roles in the preservation of organismal integrity. TGF-β signaling controls metazoan embryo development, tissue homeostasis, and injury repair through coordinated effects on cell proliferation, phenotypic plasticity, migration, metabolic adaptation, and immune surveillance of multiple cell types in shared ecosystems. Defects of TGF-β signaling, particularly in epithelial cells, tissue fibroblasts, and immune cells, disrupt immune tolerance, promote inflammation, underlie the pathogenesis of fibrosis and cancer, and contribute to the resistance of these diseases to treatment. Here, we review how TGF-β coordinates multicellular response programs in health and disease and how this knowledge can be leveraged to develop treatments for diseases of the TGF-β system.

Differential Gene and Protein Expression of Conjunctival Bleb Hyperfibrosis in Early Failure of Glaucoma Surgery

The early failure of glaucoma surgery is mainly caused by over-fibrosis at the subconjunctival space, causing obliteration of the filtration bleb. Because fibrosis has a suspected basis of genetic predisposition, we have undertaken a prospective study to identify upregulated profibrotic genes in a population of glaucoma patients with signs of conjunctival fibrosis and early postoperative surgical failure. Clinical data of re-operated fibrosis patients, hyperfibrosis patients who re-operated more than once in a short time, and control patients with no fibrosis were recorded and analyzed at each follow-up visit. Conjunctival-Tenon surgical specimens were obtained intraoperatively to evaluate the local expression of a panel of genes potentially associated with fibrosis. In order to correlate gene expression signatures with protein levels, we quantified secreted proteins in primary cultures of fibroblasts from patients. Expression of VEGFA, CXCL8, MYC, and CDKN1A was induced in the conjunctiva of hyperfibrosis patients. VEGFA and IL8 protein levels were also increased in fibroblast supernatants. We propose that an increase in these proteins could be useful in detecting conjunctival fibrosis in glaucoma patients undergoing filtering surgery. Molecular markers could be crucial for early detection of patients at high risk of failure of filtration surgery, leading to more optimal and personalized treatments.

Dichloro Ru(II)-p-cymene-1,3,5-triaza-7-phosphaadamantane (RAPTA-C): A Case Study

The use of organometallic compounds to treat various phenotypes of cancer has attracted increased interest in recent decades. Organometallic compounds, which are transitional between conventional inorganic and organic materials, have outstanding and one-of-a-kind features that offer fresh insight into the development of inorganic medicinal chemistry. The therapeutic potential of ruthenium(II)-arene RAPTA-type compounds is being thoroughly investigated, specifically owing to the excellent antimetastatic property of the initial candidate RAPTA-C. This review gives a thorough analysis of this complex and its evolution as a potential anticancer drug candidate. The numerous mechanistic investigations of RAPTA-C are discussed, and they are connected to the macroscopic biological characteristics that have been found. The "multitargeted" complex described here target enzymes, peptides, and intracellular proteins in addition to DNA that allow it to specifically target cancer cells. Understanding these may allow researchers to find specific targets and tune a new-generation organometallic complex accordingly.

The CMG helicase and cancer: a tumor "engine" and weakness with missing mutations

The replicative Cdc45-MCM-GINS (CMG) helicase is a large protein complex that functions in the DNA melting and unwinding steps as a component of replisomes during DNA replication in mammalian cells. Although the CMG performs this important role in cell growth, the CMG is not a simple bystander in cell cycle events. Components of the CMG, specifically the MCM precursors, are also involved in maintaining genomic stability by regulating DNA replication fork speeds, facilitating recovery from replicative stresses, and preventing consequential DNA damage. Given these important functions, MCM/CMG complexes are highly regulated by growth factors such as TGF-ß1 and by signaling factors such as Myc, Cyclin E, and the retinoblastoma protein. Mismanagement of MCM/CMG complexes when these signaling mediators are deregulated, and in the absence of the tumor suppressor protein p53, leads to increased genomic instability and is a contributor to tumorigenic transformation and tumor heterogeneity. The goal of this review is to provide insight into the mechanisms and dynamics by which the CMG is regulated during its assembly and activation in mammalian genomes, and how errors in CMG regulation due to oncogenic changes promote tumorigenesis. Finally, and most importantly, we highlight the emerging understanding of the CMG helicase as an exploitable vulnerability and novel target for therapeutic intervention in cancer.

Roles of TGF-β in cancer hallmarks and emerging onco-therapeutic design

Transforming growth factor-beta (TGF-β) is a double-edged sword in cancer treatment because of its pivotal yet complex and roles played during cancer initiation/development. Current anti-cancer strategies involving TGF-β largely view TGF-β as an onco-therapeutic target that not only substantially hinders its full utilisation for cancer control, but also considerably restricts innovations in this field. Thereby, how to take advantages of therapeutically favourable properties of TGF-β for cancer management represents an interesting and less investigated problem. Here, by categorising cancer hallmarks into four critical transition events and one enabling characteristic controlling cancer initiation and progression, and delineating TGF-β complexities according to these cancer traits, we identify the suppressive role of TGF-β in tumour initiation and early-stage progression and its promotive functionalities in cancer metastasis as well as other cancer hallmarks. We also propose the feasibility and possible scenarios of combining cold atmospheric plasma (CAP) with onco-therapeutics utilising TGF-β for cancer control given the intrinsic properties of CAP against cancer hallmarks.

A MYC-ZNF148-ID1/3 regulatory axis modulating cancer stem cell traits in aggressive breast cancer

The MYC proto-oncogene (MYC) is one of the most frequently overexpressed genes in breast cancer that drives cancer stem cell-like traits, resulting in aggressive disease progression and poor prognosis. In this study, we identified zinc finger transcription factor 148 (ZNF148, also called Zfp148 and ZBP-89) as a direct target of MYC. ZNF148 suppressed cell proliferation and migration and was transcriptionally repressed by MYC in breast cancer. Depletion of ZNF148 by short hairpin RNA (shRNA) and CRISPR/Cas9 increased triple-negative breast cancer (TNBC) cell proliferation and migration. Global transcriptome and chromatin occupancy analyses of ZNF148 revealed a central role in inhibiting cancer cell de-differentiation and migration. Mechanistically, we identified the Inhibitor of DNA binding 1 and 3 (ID1, ID3), drivers of cancer stemness and plasticity, as previously uncharacterized targets of transcriptional repression by ZNF148. Silencing of ZNF148 increased the stemness and tumorigenicity in TNBC cells. These findings uncover a previously unknown tumor suppressor role for ZNF148, and a transcriptional regulatory circuitry encompassing MYC, ZNF148, and ID1/3 in driving cancer stem cell traits in aggressive breast cancer.

The ubiquitin-ligase TRAF6 and TGFβ type I receptor form a complex with Aurora kinase B contributing to mitotic progression and cytokinesis in cancer cells

Background

Transforming growth factor β (TGFβ) is overexpressed in several advanced cancer types and promotes tumor progression. We have reported that the intracellular domain (ICD) of TGFβ receptor (TβR) I is cleaved by proteolytic enzymes in cancer cells, and then translocated to the nucleus in a manner dependent on the endosomal adaptor proteins APPL1/2, driving an invasiveness program. How cancer cells evade TGFβ-induced growth inhibition is unclear.

Methods

We performed microarray analysis to search for genes regulated by APPL1/2 proteins in castration-resistant prostate cancer (CRPC) cells. We investigated the role of TβRI and TRAF6 in mitosis in cancer cell lines cultured in 10% FBS in the absence of exogenous TGFβ. The molecular mechanism of the ubiquitination of AURKB by TRAF6 in mitosis and the formation of AURKB–TβRI complex in cancer cell lines and tissue microarrays was also studied.

Findings

During mitosis and cytokinesis, AURKB–TβRI complexes formed in midbodies in CRPC and KELLY neuroblastoma cells. TRAF6 induced polyubiquitination of AURKB on K85 and K87, protruding on the surface of AURKB to facilitate its activation. AURKB–TβRI complexes in patient's tumor tissue sections correlated with the malignancy of prostate cancer.

Interpretation

The AURKB–TβRI complex may become a prognostic biomarker for patients with risk of developing aggressive PC.

Funding

Swedish Medical Research Council (2019-01598, ML; 2015-02757 and 2020-01291, CHH), the Swedish Cancer Society (20 0964, ML), a regional agreement between Umeå University and Region Västerbotten (ALF; RV-939377, -967041, -970057, ML). The European Research Council (787472, CHH). KAW 2019.0345, and the Kempe Foundation SMK-1866; ML. National Microscopy Infrastructure (NMI VR-RFI 2016-00968).

Long noncoding RNA Smyca coactivates TGF-β/Smad and Myc pathways to drive tumor progression

Background

Metastasis and chemoresistance are major culprits of cancer mortality, but factors contributing to these processes are incompletely understood.

Methods

Bioinformatics methods were used to identify the relations of Smyca expression to clinicopathological features of human cancers. RNA-sequencing analysis was used to reveal Smyca-regulated transcriptome. RNA pull-down and RNA immunoprecipitation were used to examine the binding of Smyca to Smad3/4 and c-Myc/Max. Chromatin immunoprecipitation and chromatin isolation by RNA purification were used to determine the binding of transcription factors and Smyca to various gene loci, respectively. Real-time RT-PCR and luciferase assay were used to examine gene expression levels and promoter activities, respectively. Xenograft mouse models were performed to evaluate the effects of Smyca on metastasis and chemoresistance. Nanoparticle-assisted gapmer antisense oligonucleotides delivery was used to target Smyca in vivo.

Results

We identify lncRNA Smyca for its association with poor prognosis of many cancer types. Smyca potentiates metabolic reprogramming, migration, invasion, cancer stemness, metastasis and chemoresistance. Mechanistically, Smyca enhances TGF-β/Smad signaling by acting as a scaffold for promoting Smad3/Smad4 association and further serves as a Smad target to amplify/prolong TGF-β signaling. Additionally, Smyca potentiates c-Myc-mediated transcription by enhancing the recruitment of c-Myc/Max complex to a set of target promoters and c-Myc binding to TRRAP. Through potentiating TGF-β and c-Myc pathways, Smyca synergizes the Warburg effect elicited by both pathways but evades the anti-proliferative effect of TGF-β. Targeting Smyca prevents metastasis and overcomes chemoresistance.

Conclusions

This study uncovers a lncRNA that coordinates tumor-relevant pathways to orchestra a pro-tumor program and establishes the clinical values of Smyca in cancer prognosis and therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01306-3.

Realization of the T Lineage Program Involves GATA-3 Induction of Bcl11b and Repression of Cdkn2b Expression

The zinc-finger transcription factor GATA-3 plays a crucial role during early T cell development and also dictates later T cell differentiation outcomes. However, its role and collaboration with the Notch signaling pathway in the induction of T lineage specification and commitment have not been fully elucidated. We show that GATA-3 deficiency in mouse hematopoietic progenitors results in an early block in T cell development despite the presence of Notch signals, with a failure to upregulate Bcl11b expression, leading to a diversion along a myeloid, but not a B cell, lineage fate. GATA-3 deficiency in the presence of Notch signaling results in the apoptosis of early T lineage cells, as seen with inhibition of CDK4/6 (cyclin-dependent kinases 4 and 6) function, and dysregulated cyclin-dependent kinase inhibitor 2b (Cdkn2b) expression. We also show that GATA-3 induces Bcl11b, and together with Bcl11b represses Cdkn2b expression; however, loss of Cdkn2b failed to rescue the developmental block of GATA-3-deficient T cell progenitor. Our findings provide a signaling and transcriptional network by which the T lineage program in response to Notch signals is realized.

Targeting Ribosome Biogenesis to Combat Tamoxifen Resistance in ER+ve Breast Cancer

Breast cancer is a heterogeneous disease. Around 70% of breast cancers are estrogen receptor-positive (ER+ve), with tamoxifen being most commonly used as an adjuvant treatment to prevent recurrence and metastasis. However, half of the patients will eventually develop tamoxifen resistance. The overexpression of c-MYC can drive the development of ER+ve breast cancer and confer tamoxifen resistance through multiple pathways. One key mechanism is to enhance ribosome biogenesis, synthesising mature ribosomes. The over-production of ribosomes sustains the demand for proteins necessary to maintain a high cell proliferation rate and combat apoptosis induced by therapeutic agents. c-MYC overexpression can induce the expression of eIF4E that favours the translation of structured mRNA to produce oncogenic factors that promote cell proliferation and confer tamoxifen resistance. Either non-phosphorylated or phosphorylated eIF4E can mediate such an effect. Since ribosomes play an essential role in c-MYC-mediated cancer development, suppressing ribosome biogenesis may help reduce aggressiveness and reverse tamoxifen resistance in breast cancer. CX-5461, CX-3543 and haemanthamine have been shown to repress ribosome biogenesis. Using these chemicals might help reverse tamoxifen resistance in ER+ve breast cancer, provided that c-MYC-mediated ribosome biogenesis is the crucial factor for tamoxifen resistance. To employ these ribosome biogenesis inhibitors to combat tamoxifen resistance in the future, identification of predictive markers will be necessary.

Normal and Neoplastic Growth Suppression by the Extended Myc Network

Among the first discovered and most prominent cellular oncogenes is MYC, which encodes a bHLH-ZIP transcription factor (Myc) that both activates and suppresses numerous genes involved in proliferation, energy production, metabolism and translation. Myc belongs to a small group of bHLH-ZIP transcriptional regulators (the Myc Network) that includes its obligate heterodimerization partner Max and six "Mxd proteins" (Mxd1-4, Mnt and Mga), each of which heterodimerizes with Max and largely opposes Myc's functions. More recently, a second group of bHLH-ZIP proteins (the Mlx Network) has emerged that bears many parallels with the Myc Network. It is comprised of the Myc-like factors ChREBP and MondoA, which, in association with the Max-like member Mlx, regulate smaller and more functionally restricted repertoires of target genes, some of which are shared with Myc. Opposing ChREBP and MondoA are heterodimers comprised of Mlx and Mxd1, Mxd4 and Mnt, which also structurally and operationally link the two Networks. We discuss here the functions of these "Extended Myc Network" members, with particular emphasis on their roles in suppressing normal and neoplastic growth. These roles are complex due to the temporal- and tissue-restricted expression of Extended Myc Network proteins in normal cells, their regulation of both common and unique target genes and, in some cases, their functional redundancy.

Myc suppresses male-male courtship in Drosophila

Despite strong natural selection on species, same-sex sexual attraction is widespread across animals, yet the underlying mechanisms remain elusive. Here, we report that the proto-oncogene Myc is required in dopaminergic neurons to inhibit Drosophila male-male courtship. Loss of Myc, either by mutation or neuro-specific knockdown, induced males' courtship propensity toward other males. Our genetic screen identified DOPA decarboxylase (Ddc) as a downstream target of Myc. While loss of Ddc abrogated Myc depletion-induced male-male courtship, Ddc overexpression sufficed to trigger such behavior. Furthermore, Myc-depleted males exhibited elevated dopamine level in a Ddc-dependent manner, and their male-male courtship was blocked by depleting the dopamine receptor DopR1. Moreover, Myc directly inhibits Ddc transcription by binding to a target site in the Ddc promoter, and deletion of this site by genome editing was sufficient to trigger male-male courtship. Finally, drug-mediated Myc depletion in adult neurons by GeneSwitch technique sufficed to elicit male-male courtship. Thus, this study uncovered a novel function of Myc in preventing Drosophila male-male courtship, and supports the crucial roles of genetic factors in inter-male sexual behavior.

Zinc Fingers 10 and 11 of Miz-1 undergo conformational exchange to achieve specific DNA binding

Miz-1 (ZBTB17) is a poly-zinc finger BTB/POZ transcription factor with 12 consecutive C2H2 zinc fingers (ZFs) that binds transcriptional start sites (TSSs) to regulate the expression of genes involved in cell development and proliferation. As of now, it is not known which of the 12 consecutive ZFs are responsible for the recognition of the 24 base pair consensus sequence found at these TSSs. Evidence suggests ZFs 7-12 plays this role. We provide validation for this and describe the structural and dynamical characterization of unprecedented conformational exchange in the linker between ZFs 10 and 11. This conformational exchange uncouples ZFs 7-10 from 11 and 12 and promotes a scanning-recognition mechanism through which the two segments cooperate to bind two sub-sites at both ends of the consensus. We further show that this can result in the coiling of TSSs as part of Miz-1's mechanism of transcriptional transactivation.

RanBP3 Regulates Proliferation, Apoptosis and Chemosensitivity of Chronic Myeloid Leukemia Cells via Mediating SMAD2/3 and ERK1/2 Nuclear Transport

Abnormal subcellular localization of proteins is an important cause of tumorigenesis and drug resistance. Chromosome region maintenance 1 (CRM1), the nuclear export regulator of most proteins, has been confirmed to be over-expressed in various malignancies and is regarded as an efficient target. But the potential role of the CRM1 cofactor RanBP3 (Ran Binding Protein 3) is left unrevealed in chronic myeloid leukemia (CML). Here, we first detected the level of RanBP3 in CML and found an elevated RanBP3 expression in CML compared with control. Then we used shRNA lentivirus to down-regulated RanBP3 in imatinib sensitive K562 cells and resistant K562/G01 cells and found RanBP3 silencing inhibited cell proliferation by up-regulating p21, induced caspase3-related cell apoptosis, and enhanced the drug sensitivity of IM in vitro. Notably, we observed that RanBP3 silencing restored imatinib sensitivity of K562 cells in NOD/SCID mice. Mechanistically, the nuclear aggregation of SMAD2/3 revealed that tumor suppressor axis (TGF-β)-SMAD2/3-p21 was the anti-proliferation program related to RanBP3 knockdown, and the decrease of cytoplasmic ERK1/2 caused by RanBP3 interference leaded to the down-regulation of anti-apoptosis protein p(Ser112)-BAD, which was the mechanism of increased cell apoptosis and enhanced chemosensitivity to imatinib in CML. In summary, this study revealed the expression and potential role of RanBP3 in CML, suggesting that targeting RanBP3 alone or combined with TKIs could improve the clinical response of CML.

Nuclear Respiratory Factor-1, a Novel SMAD4 Binding Protein, Represses TGF-β/SMAD4 Signaling by Functioning as a Transcriptional Cofactor

SMAD4, a key regulator of transforming growth factor-β (TGF-β) signaling, plays a major role in cell growth, migration, and apoptosis. In particular, TGF-β/SMAD induces growth arrest, and SMAD4 induces the expression of target genes such as p21WAF1 and p15INK4b through its interaction with several cofactors. Thus, inactivating mutations or the homozygous deletion of SMAD4 could be related to tumorigenesis or malignancy progression. However, in some cancer types, SMAD4 is neither mutated nor deleted. In the current study, we demonstrate that TGF-β signaling with a preserved SMAD4 function can contribute to cancer through associations with negative pathway regulators. We found that nuclear respiratory factor-1 (NRF1) is a novel interaction SMAD4 partner that inhibits TGF-β/SMAD4-induced p15INK4b mRNA expression by binding to SMAD4. Furthermore, we confirmed that NRF1 directly binds to the core region of the SMAD4 promoter, thereby decreasing SMAD4 mRNA expression. On the whole, our data suggest that NRF1 is a negative regulator of SMAD4 and can interfere with TGF-β/SMAD-induced tumor suppression. Our findings provide a novel perception into the molecular basis of TGF-β/SMAD4-signaling suppression in tumorigenesis.

Dominant role of CDKN2B/p15INK4B of 9p21.3 tumor suppressor hub in inhibition of cell-cycle and glycolysis

Human chromosome 9p21.3 is susceptible to inactivation in cell immortalization and diseases, such as cancer, coronary artery disease and type-2 diabetes. Although this locus encodes three cyclin-dependent kinase (CDK) inhibitors (p15^INK4B, p14^ARF and p16^INK4A), our understanding of their functions and modes of action is limited to the latter two. Here, we show that in vitro p15^INK4B is markedly stronger than p16^INK4A in inhibiting pRb1 phosphorylation, E2F activity and cell-cycle progression. In mice, urothelial cells expressing oncogenic HRas and lacking p15^INK4B, but not those expressing HRas and lacking p16^INK4A, develop early-onset bladder tumors. The potency of CDKN2B/p15^INK4B in tumor suppression relies on its strong binding via key N-terminal residues to and inhibition of CDK4/CDK6. p15^INK4B also binds and inhibits enolase-1, a glycolytic enzyme upregulated in most cancer types. Our results highlight the dual inhibition of p15^INK4B on cell proliferation, and unveil mechanisms whereby p15^INK4B aberrations may underpin cancer and non-cancer conditions.

The human chromosome locus 9p21.3 is a tumour suppressor hub which encodes three CDK inhibitors, p15INK4B, p14ARF and p16INK4A. Here, the authors show that p15INK4B inhibits the cell cycle and glycolysis in a murine model of HRas + ‐mediated urothelial carcinoma and has a more relevant role as a tumour suppressor than its neighbouring p16INK4A.

Gene Transactivation and Transrepression in MYC-Driven Cancers

MYC is a proto-oncogene regulating a large number of genes involved in a plethora of cellular functions. Its deregulation results in activation of MYC gene expression and/or an increase in MYC protein stability. MYC overexpression is a hallmark of malignant growth, inducing self-renewal of stem cells and blocking senescence and cell differentiation. This review summarizes the latest advances in our understanding of MYC-mediated molecular mechanisms responsible for its oncogenic activity. Several recent findings indicate that MYC is a regulator of cancer genome and epigenome: MYC modulates expression of target genes in a site-specific manner, by recruiting chromatin remodeling co-factors at promoter regions, and at genome-wide level, by regulating the expression of several epigenetic modifiers that alter the entire chromatin structure. We also discuss novel emerging therapeutic strategies based on both direct modulation of MYC and its epigenetic cofactors.

Targeting MYCN in Molecularly Defined Malignant Brain Tumors

Misregulation of MYC genes, causing MYC overexpression or protein stabilization, is frequently found in malignant brain tumors highlighting their important roles as oncogenes. Brain tumors in children are the most lethal of all pediatric malignancies and the most common malignant primary adult brain tumor, glioblastoma, is still practically incurable. MYCN is one of three MYC family members and is crucial for normal brain development. It is associated with poor prognosis in many malignant pediatric brain tumor types and is focally amplified in specific adult brain tumors. Targeting MYCN has proved to be challenging due to its undruggable nature as a transcription factor and for its importance in regulating developmental programs also in healthy cells. In this review, we will discuss efforts made to circumvent the difficulty of targeting MYCN specifically by using direct or indirect measures to treat MYCN-driven brain tumors. We will further consider the mechanism of action of these measures and suggest which molecularly defined brain tumor patients that might benefit from MYCN-directed precision therapies.

Targeting TGFβ signal transduction for cancer therapy

Transforming growth factor-β (TGFβ) family members are structurally and functionally related cytokines that have diverse effects on the regulation of cell fate during embryonic development and in the maintenance of adult tissue homeostasis. Dysregulation of TGFβ family signaling can lead to a plethora of developmental disorders and diseases, including cancer, immune dysfunction, and fibrosis. In this review, we focus on TGFβ, a well-characterized family member that has a dichotomous role in cancer progression, acting in early stages as a tumor suppressor and in late stages as a tumor promoter. The functions of TGFβ are not limited to the regulation of proliferation, differentiation, apoptosis, epithelial-mesenchymal transition, and metastasis of cancer cells. Recent reports have related TGFβ to effects on cells that are present in the tumor microenvironment through the stimulation of extracellular matrix deposition, promotion of angiogenesis, and suppression of the anti-tumor immune reaction. The pro-oncogenic roles of TGFβ have attracted considerable attention because their intervention provides a therapeutic approach for cancer patients. However, the critical function of TGFβ in maintaining tissue homeostasis makes targeting TGFβ a challenge. Here, we review the pleiotropic functions of TGFβ in cancer initiation and progression, summarize the recent clinical advancements regarding TGFβ signaling interventions for cancer treatment, and discuss the remaining challenges and opportunities related to targeting this pathway. We provide a perspective on synergistic therapies that combine anti-TGFβ therapy with cytotoxic chemotherapy, targeted therapy, radiotherapy, or immunotherapy.

Hypertension and the roles of the 9p21.3 risk locus: Classic findings and new association data

BACKGROUND

The band 9p21.3 contains an established genomic risk zone for cardiovascular disease (CVD). Since the initial 2007 Wellcome Trust Case Control Consortium study (WTCCC), the increased CVD risk associated with 9p21.3 has been confirmed by multiple studies in different continents. However, many years later there was still no confirmed report of a corresponding association of 9p21.3 with hypertension, a major CV risk factor, nor with blood pressure (BP).

THEORY

In this contribution, we review the bipartite haplotype structure of the 9p21.3 risk locus: one block is devoid of protein-coding genes but contains the lead CVD risk SNPs, while the other block contains the first exon and regulatory DNA of the gene for the cell cycle inhibitor p15. We consider how findings from molecular biology offer possibilities of an involvement of p15 in hypertension etiology, with expression of the p15 gene modulated by genetic variation from within the 9p21.3 risk locus.

RESULTS

We present original results from a Colombian study revealing moderate but persistent association signals for BP and hypertension within the classic 9p21.3 CVD risk locus. These SNPs are mostly confined to a 'hypertension island' that spans less than 60 kb and coincides with the p15 haplotype block. We find confirmation in data originating from much larger, recent European BP studies, albeit with opposite effect directions.

CONCLUSION

Although more work will be needed to elucidate possible mechanisms, previous findings and new data prompt reconsidering the question of how variation in 9p21.3 might influence hypertension components of cardiovascular risk.

Leishmania regulates host macrophage miRNAs expression by engaging transcription factor c-Myc

Parasites of Leishmania genus have developed sophisticated strategies allowing them to deactivate their host macrophage to promote their survival. It has become clear that miRNAs play important roles in shaping innate and adaptive immune responses toward pathogens. It is not surprising that several pathogens including Leishmania have evolved the ability to regulate host macrophage miRNA expression in order to manipulate host cell phenotypes to their advantage. However, very little is known about the mechanisms used by intracellular pathogens to drive changes in host cell miRNA abundance. In this review, Leishmania exploitation of macrophage transcription factor c-Myc as a critical proxy virulence factor to regulate abundance of macrophage miRNAs influencing macrophage physiology to promote its survival will be discussed.

P38-β/SAPK-inhibiting and apoptosis-inducing activities of (E)-4-chloro-2-((3-ethoxy-2-hydroxybenzylidene) amino)phenol

The present study has three purposes; first evaluating cytotoxicity of (E)-4-chloro-2-((3-ethoxy-2-hydroxybenzylidene)amino)phenol (ACES), second deciphering ACES-mediated cellular death mechanism, and third estimating ACES-mediated alterations in the expressions of mitogen-activated protein kinase (MAPK) pathway-related genes. Neutral red uptake assay, cell cycle analysis, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) measurements, caspase 3/7 and 9 activations, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were implemented. IC50 values of ACES-treated five cells were around 4-6 µg/mL. However, Caco-2 and Huh-7 cells were found to be twofold resistant and fivefold sensitive with IC50 values of 11 µg/mL and 0.93 µg/mL, respectively. In this study, it was initially reported that ACES exhibits selective cytotoxicity to Huh-7 cells. In addition, ACES induced apoptosis by nuclear fragmentation, MMP disruption, and intracellular ROS elevation in MCF-7 cells. qRT-PCR experiment indicated the expressions of 30 genes including ATF2, CREB1, MYC, NFATC4 (NFAT3), CCNA1, CCNB1, CCND2, CDK2, CDKN1A (p21CIP1), CDKN1C (p57KIP2), CDKN2A (p16INK4a), CDKN2B (p15INK4b), DLK1, NRAS, CDC42, PAK1, MAP4K1 (HPK1), MAP3K3 (MEKK3), MAP2K3 (MEK3), MAP2K6 (MEK6), MOS, MAPK1 (ERK2), MAPK8 (JNK1), MAPK10 (JNK3), MAPK11 (p38-β), LAMTOR3 (MP1), MAPK8IP2 (JIP-1), PRDX6 (AOP2), COL1A1, and HSPA5 (Grp78) were downregulated at least 1.5-fold. Moreover, ACES effectively inhibited expressions of genes that code for elements of p38-β/stress-activated protein kinase (SAPK) pathway. ACES has the potential to be used for the reversal of trastuzumab resistance in breast cancer patients by inhibiting p38/SAPK pathway in MCF-7 cells. Therefore, with the selective cytotoxic, apoptosis-inducing, and p38-β/SAPK-inhibiting activities, ACES can be utilized for developing a novel anticancer drug.

Identification of the transcription factor Miz1 as an essential regulator of diphthamide biosynthesis using a CRISPR-mediated genome-wide screen

Diphthamide is a unique post-translationally modified histidine residue (His715 in all mammals) found only in eukaryotic elongation factor-2 (eEF-2). The biosynthesis of diphthamide represents one of the most complex modifications, executed by protein factors conserved from yeast to humans. Diphthamide is not only essential for normal physiology (such as ensuring fidelity of mRNA translation), but is also exploited by bacterial ADP-ribosylating toxins (e.g., diphtheria toxin) as their molecular target in pathogenesis. Taking advantage of the observation that cells defective in diphthamide biosynthesis are resistant to ADP-ribosylating toxins, in the past four decades, seven essential genes (Dph1 to Dph7) have been identified for diphthamide biosynthesis. These technically unsaturated screens raise the question as to whether additional genes are required for diphthamide biosynthesis. In this study, we performed two independent, saturating, genome-wide CRISPR knockout screens in human cells. These screens identified all previously known Dph genes, as well as further identifying the BTB/POZ domain-containing transcription factor Miz1. We found that Miz1 is absolutely required for diphthamide biosynthesis via its role in the transcriptional regulation of Dph1 expression. Mechanistically, Miz1 binds to the Dph1 proximal promoter via an evolutionarily conserved consensus binding site to activate Dph1 transcription. Therefore, this work demonstrates that Dph1-7, along with the newly identified Miz1 transcription factor, are likely to represent the essential protein factors required for diphthamide modification on eEF2.

Dual role of TGF-β in early pregnancy: clues from tumor progression

TGF-β signaling in the endometrium is active during the implantation period and has a pivotal role in regulating endometrial receptivity and embryo implantation. During embryo implantation, both apoptosis and proliferation of endometrial cells happen at the same time and it seems TGF-β is the factor that controls both of these processes. As shown in cancer cells, in special conditions this cytokine can have a dual effect and switch the action from apoptosis to proliferation. Owing to the similarity between embryo implantation and cancer development and also unusual pattern of proliferation and remodeling in the uterus, in this review we suggest the existence of such a switching in endometrium during the early pregnancy. Moreover, we address some potential mechanisms that could regulate the switching. A better understanding of the molecular mechanisms regulating TGF-β action and signaling during the implantation period could pave the way for introducing novel therapeutic strategies in order to solve implantation-associated issues such as repeated implantation failure.

PRMT5-dependent transcriptional repression of c-Myc target genes promotes gastric cancer progression

The proto-oncogene c-Myc regulates multiple biological processes mainly through selectively activating gene expression. However, the mechanisms underlying c-Myc-mediated gene repression in the context of cancer remain less clear. This study aimed to clarify the role of PRMT5 in the transcriptional repression of c-Myc target genes in gastric cancer.

Methods: Immunohistochemistry was used to evaluate the expression of PRMT5, c-Myc and target genes in gastric cancer patients. PRMT5 and c-Myc interaction was assessed by immunofluorescence, co-immunoprecipitation and GST pull-down assays. Bioinformatics analysis, immunoblotting, real-time PCR, chromatin immunoprecipitation, and rescue experiments were used to evaluate the mechanism.

Results: We found that c-Myc directly interacts with protein arginine methyltransferase 5 (PRMT5) to transcriptionally repress the expression of a cohort of genes, including PTEN, CDKN2C (p18^INK4C), CDKN1A (p21^CIP1/WAF1), CDKN1C (p57^KIP2) and p63, to promote gastric cancer cell growth. Specifically, we found that PRMT5 was required to promote gastric cancer cell growth in vitro and in vivo, and for transcriptional repression of this cohort of genes, which was dependent on its methyltransferase activity. Consistently, the promoters of this gene cohort were enriched for both PRMT5-mediated symmetric di-methylation of histone H4 on Arg 3 (H4R3me2s) and c-Myc, and c-Myc depletion also upregulated their expression. H4R3me2s also colocalized with the c-Myc-binding E-box motif (CANNTG) on these genes. We show that PRMT5 directly binds to c-Myc, and this binding is required for transcriptional repression of the target genes. Both c-Myc and PRMT5 expression levels were upregulated in primary human gastric cancer tissues, and their expression levels inversely correlated with clinical outcomes.

Conclusions: Taken together, our study reveals a novel mechanism by which PRMT5-dependent transcriptional repression of c-Myc target genes is required for gastric cancer progression, and provides a potential new strategy for therapeutic targeting of gastric cancer.

Smad3 signalling affects high glucose-induced podocyte injury via regulation of the cytoskeletal protein transgelin

Aim

The aim of the present study was to characterize the role of Smad3 signalling on high glucose‐induced podocyte injury.

Methods

Synchronized conditionally immortalized mouse podocyte cell line (MPC5) cells were treated with either D‐glucose alone or D‐glucose plus the Smad3 inhibitor SIS3. The distribution of F‐actin and transgelin in a high glucose‐induced model of podocyte injury were examined by immunofluorescence. Levels of transgelin and Smad3 signalling proteins in MPC5 cells were determined by Western blot.

Results

A disordered distribution of F‐actin, as well as co‐localization of F‐actin and transgelin, was observed in podocytes exposed to high glucose. Increased levels of transgelin were first observed 10 minutes after treatment with glucose, suggesting that this protein is sensitive to hyperglycaemic injury. Levels of phosphorylated Smad3 and cleaved caspase 3 increased significantly with glucose stimulation. Moreover, expression of the downstream protein c‐Myc, but not JAK1/STAT3, was induced in conditions of high glucose. The Smad3‐specific inhibitor SIS3 prevented the effects of high glucose on Smad3 phosphorylation, expression of transgelin and c‐Myc, caspase 3 cleavage and cytoskeletal organization. Expression of the tumour suppressor protein p15^INK4B increased after podocyte injury but was unaffected by Smad3 inhibition, suggesting that Smad3 regulation of high glucose‐induced podocyte injury occurs through a p15^INK4B‐independent mechanism.

Conclusion

Smad3 signalling plays a critical role in the modulation of hyperglycaemic injury. Targeted inhibition of the Smad3 pathway may offer a novel route for treatment of podocyte damage, especially in cases of diabetic nephropathy.

Podocyte damage is characteristic of diabetic kidney disease. This study showed that inhibition of Smad‐3 signalling using the specific inhibitor SIS3 in vitro, could alleviate podocyte abnormalities induced by high glucose including actin cytoskeletal rearrangement and actviation of cell death pathways.

Target gene-independent functions of MYC oncoproteins

Oncoproteins of the MYC family are major drivers of human tumorigenesis. Since a large body of evidence indicates that MYC proteins are transcription factors, studying their function has focused on the biology of their target genes. Detailed studies of MYC-dependent changes in RNA levels have provided contrasting models of the oncogenic activity of MYC proteins through either enhancing or repressing the expression of specific target genes, or as global amplifiers of transcription. In this Review, we first summarize the biochemistry of MYC proteins and what is known (or is unclear) about the MYC target genes. We then discuss recent progress in defining the interactomes of MYC and MYCN and how this information affects central concepts of MYC biology, focusing on mechanisms by which MYC proteins modulate transcription. MYC proteins promote transcription termination upon stalling of RNA polymerase II, and we propose that this mechanism enhances the stress resilience of basal transcription. Furthermore, MYC proteins coordinate transcription elongation with DNA replication and cell cycle progression. Finally, we argue that the mechanism by which MYC proteins regulate the transcription machinery is likely to promote tumorigenesis independently of global or relative changes in the expression of their target genes.

Modeling medulloblastoma in vivo and with human cerebellar organoids

Medulloblastoma (MB) is the most common malignant brain tumor in children and among the subtypes, Group 3 MB has the worst outcome. Here, we perform an in vivo, patient-specific screen leading to the identification of Otx2 and c-MYC as strong Group 3 MB inducers. We validated our findings in human cerebellar organoids where Otx2/c-MYC give rise to MB-like organoids harboring a DNA methylation signature that clusters with human Group 3 tumors. Furthermore, we show that SMARCA4 is able to reduce Otx2/c-MYC tumorigenic activity in vivo and in human cerebellar organoids while SMARCA4 T910M, a mutant form found in human MB patients, inhibits the wild-type protein function. Finally, treatment with Tazemetostat, a EZH2-specific inhibitor, reduces Otx2/c-MYC tumorigenesis in ex vivo culture and human cerebellar organoids. In conclusion, human cerebellar organoids can be efficiently used to understand the role of genes found altered in cancer patients and represent a reliable tool for developing personalized therapies.