The ZMYND8-regulated mevalonate pathway endows YAP-high intestinal cancer with metabolic vulnerability

Unlocking the lipid code: SREBPs as key drivers in gastrointestinal tumour metabolism

In recent years, metabolic reprogramming has emerged as a significant breakthrough in elucidating the onset and progression of gastrointestinal (GI) malignancies. As central regulatory hubs for lipid metabolism, sterol regulatory element binding proteins (SREBPs) integrate dietary metabolic signals and carcinogenic stimuli through subtype-specific mechanisms, thereby promoting malignant tumour phenotypes. In this review, we first present the molecular background, structural characteristics, and posttranscriptional regulatory networks associated with SREBPs. We subsequently describe a systematic analysis of the distinct activation patterns of SREBPs in liver, gastric, colorectal, and other gastrointestinal cancers. Furthermore, we explore targeted intervention strategies for different SREBP subtypes, including small molecule inhibitors (such as fatostatin, which inhibits SREBP cleavage), natural compounds (such as berberine, which modulates the AMPK/mTOR pathway), and statin-mediated inhibition of the mevalonic acid pathway. These strategies may enhance tumour cell sensitivity to chemotherapeutic agents (such as 5-FU, gezil, and tabine) and improve the response to synergistic chemoradiotherapy by reversing adaptive metabolic resistance driven by the tumour microenvironment. Through this review, we hope to provide new insights into precise interventions targeting various subtypes of the SREBP molecule.

The roles of enhancer, especially super-enhancer-driven genes in tumor metabolism and immunity

Abnormal metabolism is a characteristic of malignant tumors. Numerous factors play roles in the regulation of tumor metabolism. As epigenetic regulators, enhancers, especially the super-enhancers (SEs), serve as platforms for transcription factors that regulate the expression of metabolism-related enzymes or transporters at the gene level. In this study, we review the effects of enhancer/ SE-driven genes on tumor metabolism and immunity. Enhancers/SEs play regulatory roles in glucose metabolism (glycolysis, gluconeogenesis, tricarboxylic acid (TCA) cycle, pyruvate, and pentose phosphate pathway, lipid metabolism (cholesterol, fatty acid, phosphatide, and sphingolipid), and amino acid metabolism (glutamine, tryptophan, arginine, and cystine). By regulating tumor metabolism, enhancers and SEs can reprogram tumor microenvironment, especially the status of various immune cells. Therefore, interfering enhancers/SEs that regulate the tumor metabolism is likely to enhance the effectiveness of immunotherapy.

ZMYND8 Reads H3K36me2 to Activate CEBPE Transcription and Suppress Multiple Myeloma Progression through the Inhibition of Adaptive UPR Pathways

Multiple myeloma (MM) pathogenesis is closely associated with aberrant epigenetic regulation and resulting modifications, such as dimethylation of lysine 36 in histone H3 (H3K36me2). However, the recognition signature of H3K36me2 and its functional role in MM remain largely unknown. Here, the zinc-finger MYND-type-containing 8 (ZMYND8) is identified as a potential reader of the H3K36me2 mark that suppresses MM progression. ZMYND8 knockdown promotes the proliferation and invasion of MM cells. Combined transcriptomic and epigenomic analyses reveal that CCAAT/enhancer-binding protein epsilon (CEBPE) is a direct downstream target of ZMYND8. CEBPE modulates adaptive unfolded protein response (UPR) pathways through the transcriptional repression of ERN1, XBP1, and ATF6 to impair cell survival. Coimmunoprecipitation and chromatin immunoprecipitation assays show that ZMYND8 activates CEBPE expression in an H3K36me2-dependent manner and that its Pro-Trp-Trp-Pro domain is required for binding H3K36me2 modules, leading to CEBPE transcription. Low ZMYND8 expression is significantly correlated with adverse clinicopathological features and poor survival outcomes in MM patients. Furthermore, ZMYND8 upregulation increases the sensitivity of MM cells to carfilzomib. Taken together, these findings demonstrate that ZMYND8 epigenetically activates CEBPE transcription and suppresses MM cell growth by inhibiting the adaptive UPR, suggesting that ZMYND8 can be a novel therapeutic target for patients with MM.

ZMYND8 drives HER2 antibody resistance in breast cancer via lipid control of IL-27

Anti-HER2 antibodies are effective but often lead to resistance in patients with HER2+ breast cancer. Here, we report an epigenetic crosstalk with aberrant glycerophospholipid metabolism and inflammation as a key resistance mechanism of anti-HER2 therapies in HER2+ breast cancer. Histone reader ZMYND8 specifically confers resistance to cancer cells against trastuzumab and/or pertuzumab. Mechanistically, ZMYND8 enhances cPLA2α expression in resistant tumor cells through inducing c-Myc. cPLA2α inactivates phosphatidylcholine-specific phospholipase C to inhibit phosphatidylcholine breakdown into diacylglycerol, which diminishes protein kinase C activity leading to interleukin-27 secretion. Supplementation with interleukin-27 protein counteracts cPLA2α loss to reinforce trastuzumab resistance in HER2+ tumor cells and patient-derived organoids. Upregulation of ZMYND8, c-Myc, cPLA2α, and IL-27 is prevalent in HER2+ breast cancer patients following HER2-targeted therapies. Targeting c-Myc or cPLA2α effectively overcomes anti-HER2 therapy resistance in patient-derived xenografts. Collectively, this study uncovers a druggable signaling cascade that drives resistance to HER2-targeted therapies in HER2+ breast cancer.

SREBP2 as a central player in cancer progression: potential for targeted therapeutics

Recent studies have identified the reprogramming of lipid metabolism as a critical hallmark of malignancy. Enhanced cholesterol uptake and increased cholesterol biosynthesis significantly contribute to the rapid growth of tumors, with cholesterol also playing essential roles in cellular signaling pathways. Targeting cholesterol metabolism has emerged as a promising therapeutic strategy in oncology. The sterol regulatory element-binding protein-2 (SREBP2) serves as a primary transcriptional regulator of genes involved in cholesterol biosynthesis and is crucial for maintaining cholesterol homeostasis. Numerous studies have reported the upregulation of SREBP2 across various cancers, facilitating tumor progression. This review aims to provide a comprehensive overview of the structure, biological functions, and regulatory mechanisms of SREBP2. Furthermore, we summarize that SREBP2 plays a crucial role in various cancers and tumor microenvironment primarily by regulating cholesterol, as well as through several non-cholesterol pathways. We also particularly emphasize therapeutic agents targeting SREBP2 that are currently under investigation. This review seeks to enhance our understanding of SREBP2's involvement in cancer and provide theoretical references for cancer therapies that target SREBP2.

The RBM39 degrader indisulam inhibits acute megakaryoblastic leukemia by altering the alternative splicing of ZMYND8

BACKGROUND

Acute megakaryoblastic leukemia (AMKL) is a rare hematological malignancy in adults but children. Alternative splicing (AS) has been shown to affect hematological cancer progression, making splicing factors promising targets. Our research aims to investigate the efficacy of the molecular glue degrader indisulam, which targets the splicing factor RNA binding motif protein 39 (RBM39) in AMKL models.

RESULTS

Public drug sensitivity data analysis revealed that AMKL cell lines exhibited the highest sensitivity to indisulam compared with other tumor types. Then we confirmed that RBM39 depletion by indisulam treatment induced AMKL cell cycle arrest and apoptosis. In AMKL mouse model, indisulam treatment significantly reduced the leukemic burden and prolonged the lifetime of AMKL mice. Mechanically, integration of transcriptomic and proteomic analyses revealed that indisulam-mediated RBM39 degradation resulted in AS of the transcription factor zinc finger MYND-type containing 8 (ZMYND8), an AMKL cell growth regulator. Finally, the effectiveness of indisulam depended on DDB1- and Cul4- Associated Factor 15 (DCAF15) expression because knockout of DCAF15 rescued the indisulam-induced RBM39 degradation and mis-splicing of ZMYND8.

CONCLUSION

Indisulam is a promising therapeutic candidate for AMKL and the RBM39-mediated ZMYND8 splicing plays an important role in promoting the development of AMKL.

The Mevalonate Pathway in the Radiation Response of Cancer

The mevalonate (MVA) pathway plays a critical role in cholesterol biosynthesis, protein prenylation, and metabolic reprogramming, all of which contribute to cancer progression and therapy resistance. Targeting the MVA pathway with statins and other inhibitors has shown promise in preclinical studies; however, clinical outcomes remain controversial, raising concerns about translating these findings into effective treatments. Additionally, the interaction between the MVA pathway and radiation therapy (RT) is not yet fully understood, as RT upregulates the pathway, which can enhance tumor cell survival. This review summarizes the current literature on MVA pathway inhibition in cancer therapy, focusing on its potential to enhance the efficacy of RT. A better understanding of the pathway's role in radiation responses will be essential to translate combination therapies that target this pathway.

Targeting the histone reader ZMYND8 inhibits antiandrogen-induced neuroendocrine tumor transdifferentiation of prostate cancer

The transdifferentiation from adenocarcinoma to neuroendocrine prostate cancer (NEPC) in men confers antiandrogen therapy resistance. Here our analysis combining CRISPR‒Cas9 screening with single-cell RNA sequencing tracking of tumor transition demonstrated that antiandrogen-induced zinc finger MYND-type containing 8 (ZMYND8)-dependent epigenetic programming orchestrates NEPC transdifferentiation. Ablation of Zmynd8 prevents NEPC development, while ZMYND8 upregulation mediated by achaete-scute homolog 1 promotes NEPC differentiation. We show that forkhead box protein M1 (FOXM1) stabilizes ZMYND8 binding to chromatin regions characterized by H3K4me1-H3K14ac modification and FOXM1 targeting. Antiandrogen therapy releases the SWI/SNF chromatin remodeling complex from the androgen receptor, facilitating its interaction with ZMYND8-FOXM1 to upregulate critical neuroendocrine lineage regulators. We develop iZMYND8-34, a small molecule designed to inhibit ZMYND8's histone recognition, which effectively blocks NEPC development. These findings reveal the critical role of ZMYND8-dependent epigenetic programming induced by androgen deprivation therapy in orchestrating lineage fate. Targeting ZMYND8 emerges as a promising strategy for impeding NEPC development.

HDAC2 promotes colorectal tumorigenesis by triggering dysregulation of lipid metabolism through YAP1

Dysfunction of lipid metabolism is important for the development and progression of colorectal cancer, but the underlying mechanisms remain unclear. Here, HDAC2 was identified as highly expressed in both adenoma and colorectal cancer. We aimed to explore the roles and mechanisms of HDAC2 in lipid metabolism in colorectal cancer. HDAC2 expression in adenoma and colorectal cancer tissues was measured using tissue arrays. The function of HDAC2/YAP1 was identified using in vitro and in vivo experiments. Coimmunoprecipitation experiments, DNA pull-down assays, luciferase analyses, and ChIP-qPCR (Chromatin Immunoprecipitation-quantitative real-time polymerase chain reaction) assays were used to identify the potential mechanisms of HDAC2. We found that HDAC2 can disrupt lipid metabolism in colorectal cancer by mediating the deacetylation of YAP1. Mechanistically, HDAC2 can bind to YAP1 and mediate deacetylation of the K280 site of YAP1. Furthermore, the deacetylation of YAP1 reduces the efficiency of its binding to the ZMYND11 promoter region, exacerbating lipid metabolism disorders, which in turn reduce lipid accumulation and increase lipid catabolism in colorectal cancer cells. Our study identified a novel regulatory mechanism of lipid metabolism in colorectal cancer in which HDAC2 increases lipid catabolism by regulating the deacetylation of the K280 site of YAP1, revealing that HDAC2 promotes tumor progression through the regulation of lipid metabolism.

Intestinal Foxl1+ cell-derived CXCL12 maintains epithelial homeostasis by modulating cellular metabolism

Several mesenchymal cell populations are known to regulate intestinal stem cell (ISC) self-renewal and differentiation. However, the influences of signaling mediators derived from mesenchymal cells other than ISC niche factors on epithelial homeostasis remain poorly understood. Here, we show that host and microbial metabolites, such as taurine and gamma-aminobutyric acid (GABA), act on PDGFRαhigh Foxl1high sub-epithelial mesenchymal cells to regulate their transcription. In addition, we found that CXC chemokine ligand 12 (CXCL12) produced from Foxl1high sub-epithelial mesenchymal cells induces epithelial cell cycle arrest through modulation of the mevalonate-cholesterol synthesis pathway, which suppresses tumor progression in ApcMin/+ mice. We identified that Foxl1high sub-epithelial cells highly express CXCL12 among colonic mesenchymal cells. Foxl1-cre; Cxcl12f/f mice showed an increased number of Ki67+ colonic epithelial cells. CXCL12-induced Ca2+ mobilization facilitated phosphorylation of AMPK in intestinal epithelial cells, which inhibits the maturation of sterol regulatory element-binding proteins (SREBPs) that are responsible for mevalonate pathway activation. Furthermore, Cxcl12 deficiency in Foxl1-expressing cells promoted tumor development in the small and large intestines of ApcMin/+ mice. Collectively, these results demonstrate that CXCL12 secreted from Foxl1high mesenchymal cells manipulates intestinal epithelial cell metabolism, which links to the prevention of tumor progression in ApcMin/+ mice.

The Role of Yes-Associated Protein in Inflammatory Diseases and Cancer

Yes-associated protein (YAP) plays a central role in the Hippo pathway, primarily governing cell proliferation, differentiation, and apoptosis. Its significance extends to tumorigenesis and inflammatory conditions, impacting disease initiation and progression. Given the increasing relevance of YAP in inflammatory disorders and cancer, this study aims to elucidate its pathological regulatory functions in these contexts. Specifically, we aim to investigate the involvement and molecular mechanisms of YAP in various inflammatory diseases and cancers. We particularly focus on how YAP activation, whether through Hippo-dependent or independent pathways, triggers the release of inflammation and inflammatory mediators in respiratory, cardiovascular, and digestive inflammatory conditions. In cancer, YAP not only promotes tumor cell proliferation and differentiation but also modulates the tumor immune microenvironment, thereby fostering tumor metastasis and progression. Additionally, we provide an overview of current YAP-targeted therapies. By emphasizing YAP's role in inflammatory diseases and cancer, this study aims to enhance our understanding of the protein's pivotal involvement in disease processes, elucidate the intricate pathological mechanisms of related diseases, and contribute to future drug development strategies targeting YAP.

Patient-derived xenograft model in cancer: establishment and applications

The patient-derived xenograft (PDX) model is a crucial in vivo model extensively employed in cancer research that has been shown to maintain the genomic characteristics and pathological structure of patients across various subtypes, metastatic, and diverse treatment histories. Various treatment strategies utilized in PDX models can offer valuable insights into the mechanisms of tumor progression, drug resistance, and the development of novel therapies. This review provides a comprehensive overview of the establishment and applications of PDX models. We present an overview of the history and current status of PDX models, elucidate the diverse construction methodologies employed for different tumors, and conduct a comparative analysis to highlight the distinct advantages and limitations of this model in relation to other in vivo models. The applications are elucidated in the domain of comprehending the mechanisms underlying tumor development and cancer therapy, which highlights broad applications in the fields of chemotherapy, targeted therapy, delivery systems, combination therapy, antibody-drug conjugates and radiotherapy. Furthermore, the combination of the PDX model with multiomics and single-cell analyses for cancer research has also been emphasized. The application of the PDX model in clinical treatment and personalized medicine is additionally emphasized.

Catalytic-independent functions of the Integrator-PP2A complex (INTAC) confer sensitivity to BET inhibition

Chromatin and transcription regulators are critical to defining cell identity through shaping epigenetic and transcriptional landscapes, with their misregulation being closely linked to oncogenesis. Pharmacologically targeting these regulators, particularly the transcription-activating BET proteins, has emerged as a promising approach in cancer therapy, yet intrinsic or acquired resistance frequently occurs, with poorly understood mechanisms. Here, using genome-wide CRISPR screens, we find that BET inhibitor efficacy in mediating transcriptional silencing and growth inhibition depends on the auxiliary/arm/tail module of the Integrator-PP2A complex (INTAC), a global regulator of RNA polymerase II pause-release dynamics. This process bypasses a requirement for the catalytic activities of INTAC and instead leverages direct engagement of the auxiliary module with the RACK7/ZMYND8-KDM5C complex to remove histone H3K4 methylation. Targeted degradation of the COMPASS subunit WDR5 to attenuate H3K4 methylation restores sensitivity to BET inhibitors, highlighting how simultaneously targeting coordinated chromatin and transcription regulators can circumvent drug-resistant tumors.

Positive feedback between arginine methylation of YAP and methionine transporter SLC43A2 drives anticancer drug resistance

Yes-associated protein (YAP) activation confers resistance to chemotherapy and targeted therapy. Methionine participates in cellular processes by converting to methyl donor for the methylation of DNA, RNA and protein. However, it remains unclear whether methionine affects drug resistance by influencing YAP activity. In this study, we report that methionine deprivation remarkably suppresses the transcriptional activity of YAP-TEAD in cancer cells. Methionine promotes PRMT1-catalyzed asymmetric dimethylation at R124 of YAP (YAP R124me2a). Mimicking of YAP methylation abolishes the reduction effect of methionine-restricted diet on YAP-induced drug resistance. YAP activates the transcription of SLC43A2, the methionine transporter, to increase methionine uptake in cancer cells. Knockdown of SLC43A2 decreases the level of YAP R124me2a. BCH, the inhibitor of SLC43A2, sensitizes tumors to anticancer drugs. Thus, our results unravel the positive feedback between YAP R124 methylation and SLC43A2 that contributes to anticancer drug resistance. Disrupting this positive feedback could be a potential strategy for cancer therapy.

USP7 deubiquitinates epigenetic reader ZMYND8 to promote breast cancer cell migration and invasion

The ubiquitin-proteasome system (UPS), which involves E3 ligases and deubiquitinates (DUBs), is critical for protein homeostasis. The epigenetic reader ZMYND8 (zinc finger MYND-type containing 8) has emerged as an oncoprotein, and its protein levels are elevated in various types of cancer, including breast cancer. However, the mechanism by which ZMYND8 protein levels are increased in cancer remains elusive. Although ZMYND8 has been reported to be regulated by the E3 ligase FBXW7, it is still unknown whether ZMYND8 could be modulated by DUBs. Here, we identified USP7 (ubiquitin carboxyl-terminal hydrolase 7) as a bona fide DUB for ZMYND8. Mechanically, USP7 directly binds to the PBP (PHD-BRD-PWWP) domain of ZMYND8 via its TRAF (tumor necrosis factor receptor-associated factor) domain and UBL (ubiquitin-like) domain and removes F-box and WD repeat domain containing 7 (FBXW7)-catalyzed poly-ubiquitin chains on lysine residue 1034 (K1034) within ZMYND8, thereby stabilizing ZMYND8 and stimulating the transcription of ZMYND8 target genes ZEB1 (zinc finger E-box binding homeobox 1) and VEGFA (Vascular Endothelial Growth Factor A). Consequently, USP7 enhances the capacity of breast cancer cells for migration and invasion through antagonizing FBXW7-mediated ZMYND8 degradation. Importantly, the protein levels of USP7 positively correlates with those of ZMYND8 in breast cancer tissues. These findings delineate an important layer of migration and invasion regulation by the USP7-ZMYND8 axis in breast cancer cells.

DNA methylation modulates epigenetic regulation in colorectal cancer diagnosis, prognosis and precision medicine

Colorectal cancer (CRC) is a multifaceted disease influenced by the interplay of genetic and environmental factors. The clinical heterogeneity of CRC cannot be attributed exclusively to genetic diversity and environmental exposures, and epigenetic markers, especially DNA methylation, play a critical role as key molecular markers of cancer. This review compiles a comprehensive body of evidence underscoring the significant involvement of DNA methylation modifications in the pathogenesis of CRC. Moreover, this review explores the potential utility of DNA methylation in cancer diagnosis, prognostics, assessment of disease activity, and prediction of drug responses. Recognizing the impact of DNA methylation will enhance the ability to identify distinct CRC subtypes, paving the way for personalized treatment strategies and advancing precision medicine in the management of CRC.

ZMYND8 protects breast cancer stem cells against oxidative stress and ferroptosis through activation of NRF2

Breast cancer stem cells (BCSCs) mitigate oxidative stress to maintain their viability and plasticity. However, the regulatory mechanism of oxidative stress in BCSCs remains unclear. We recently found that the histone reader ZMYND8 was upregulated in BCSCs. Here, we showed that ZMYND8 reduced ROS and iron to inhibit ferroptosis in aldehyde dehydrogenase-high (ALDHhi) BCSCs, leading to BCSC expansion and tumor initiation in mice. The underlying mechanism involved a two-fold posttranslational regulation of nuclear factor erythroid 2-related factor 2 (NRF2). ZMYND8 increased stability of NRF2 protein through KEAP1 silencing. On the other hand, ZMYND8 interacted with and recruited NRF2 to the promoters of antioxidant genes to enhance gene transcription in mammospheres. NRF2 phenocopied ZMYND8 to enhance BCSC stemness and tumor initiation by inhibiting ROS and ferroptosis. Loss of NRF2 counteracted ZMYND8's effects on antioxidant genes and ROS in mammospheres. Interestingly, ZMYND8 expression was directly controlled by NRF2 in mammospheres. Collectively, these findings uncover a positive feedback loop that amplifies the antioxidant defense mechanism sustaining BCSC survival and stemness.

Enhanced SREBP2-driven cholesterol biosynthesis by PKCλ/ι deficiency in intestinal epithelial cells promotes aggressive serrated tumorigenesis

The metabolic and signaling pathways regulating aggressive mesenchymal colorectal cancer (CRC) initiation and progression through the serrated route are largely unknown. Although relatively well characterized as BRAF mutant cancers, their poor response to current targeted therapy, difficult preneoplastic detection, and challenging endoscopic resection make the identification of their metabolic requirements a priority. Here, we demonstrate that the phosphorylation of SCAP by the atypical PKC (aPKC), PKCλ/ι promotes its degradation and inhibits the processing and activation of SREBP2, the master regulator of cholesterol biosynthesis. We show that the upregulation of SREBP2 and cholesterol by reduced aPKC levels is essential for controlling metaplasia and generating the most aggressive cell subpopulation in serrated tumors in mice and humans. Since these alterations are also detected prior to neoplastic transformation, together with the sensitivity of these tumors to cholesterol metabolism inhibitors, our data indicate that targeting cholesterol biosynthesis is a potential mechanism for serrated chemoprevention.

CRISPR/Cas9: a powerful tool in colorectal cancer research

Colorectal cancer (CRC) is one of the most common malignant cancers worldwide and seriously threatens human health. The clustered regulatory interspaced short palindromic repeat/CRISPR-associate nuclease 9 (CRISPR/Cas9) system is an adaptive immune system of bacteria or archaea. Since its introduction, research into various aspects of treatment approaches for CRC has been accelerated, including investigation of the oncogenes, tumor suppressor genes (TSGs), drug resistance genes, target genes, mouse model construction, and especially in genome-wide library screening. Furthermore, the CRISPR/Cas9 system can be utilized for gene therapy for CRC, specifically involving in the molecular targeted drug delivery or targeted knockout in vivo. In this review, we elucidate the mechanism of the CRISPR/Cas9 system and its comprehensive applications in CRC. Additionally, we discussed the issue of off-target effects associated with CRISPR/Cas9, which serves to restrict its practical application. Future research on CRC should in-depth and systematically utilize the CRISPR/Cas9 system thereby achieving clinical practice.

Advanced Progression for the Heterogeneity and Homeostasis of Intestinal Stem Cells

Current understanding of the leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) in intestinal stem cells (ISCs) is well established, however, the implications of ISC heterogeneity and homeostasis are poorly understood. Prior studies have provided important evidence for the association between heterogeneity of ISC pools with pathogenesis and therapeutic response of malignant disease. Leveraging the advantages of organoids and single cell RNA sequencing (scRNA-seq), glandular development has been simulated and cell heterogeneity has been clarified. Based on this research, several potential ISCs were identified, such as LGR5 + p27 + quiescent ISCs, LGR5 + Mex3a + slowly proliferating stem cells, and CLU + reverse stem cells. We also illustrated major factors responsible for ISC homeostasis including metabolism-related (LKB1, TGR5, HMGCS2), inflammation-related (IFB-b, IFN2, TNF), and Wnt signaling-related (CREPT, Mex3a, MTG16) factors. ISCs play complex roles in intestinal tumorigenesis, chemoresistance and occasional relapse of colon cancer, which bear discussion. In this review, we focus on novel technical challenges in ISCs fate drawing upon recent research with the goals of clarifying our understanding of complex ISCs, elucidating the integrated intestinal crypt niche, and creating new opportunities for therapeutic development.

Functional significance of cholesterol metabolism in cancer: from threat to treatment

Cholesterol is an essential structural component of membranes that contributes to membrane integrity and fluidity. Cholesterol homeostasis plays a critical role in the maintenance of cellular activities. Recently, increasing evidence has indicated that cholesterol is a major determinant by modulating cell signaling events governing the hallmarks of cancer. Numerous studies have shown the functional significance of cholesterol metabolism in tumorigenesis, cancer progression and metastasis through its regulatory effects on the immune response, ferroptosis, autophagy, cell stemness, and the DNA damage response. Here, we summarize recent literature describing cholesterol metabolism in cancer cells, including the cholesterol metabolism pathways and the mutual regulatory mechanisms involved in cancer progression and cholesterol metabolism. We also discuss various drugs targeting cholesterol metabolism to suggest new strategies for cancer treatment.

The Roles of Zinc Finger Proteins in Colorectal Cancer

Despite colorectal cancer remaining a leading worldwide cause of cancer-related death, there remains a paucity of effective treatments for advanced disease. The molecular mechanisms underlying the development of colorectal cancer include altered cell signaling and cell cycle regulation that may result from epigenetic modifications of gene expression and function. Acting as important transcriptional regulators of normal biological processes, zinc finger proteins also play key roles in regulating the cellular mechanisms underlying colorectal neoplasia. These actions impact cell differentiation and proliferation, epithelial-mesenchymal transition, apoptosis, homeostasis, senescence, and maintenance of stemness. With the goal of highlighting promising points of therapeutic intervention, we review the oncogenic and tumor suppressor roles of zinc finger proteins with respect to colorectal cancer tumorigenesis and progression.

Orchestral role of lipid metabolic reprogramming in T-cell malignancy

The immune function of normal T cells partially depends on the maneuvering of lipid metabolism through various stages and subsets. Interestingly, T-cell malignancies also reprogram their lipid metabolism to fulfill bioenergetic demand for rapid division. The rewiring of lipid metabolism in T-cell malignancies not only provides survival benefits but also contributes to their stemness, invasion, metastasis, and angiogenesis. Owing to distinctive lipid metabolic programming in T-cell cancer, quantitative, qualitative, and spatial enrichment of specific lipid molecules occur. The formation of lipid rafts rich in cholesterol confers physical strength and sustains survival signals. The accumulation of lipids through de novo synthesis and uptake of free lipids contribute to the bioenergetic reserve required for robust demand during migration and metastasis. Lipid storage in cells leads to the formation of specialized structures known as lipid droplets. The inimitable changes in fatty acid synthesis (FAS) and fatty acid oxidation (FAO) are in dynamic balance in T-cell malignancies. FAO fuels the molecular pumps causing chemoresistance, while FAS offers structural and signaling lipids for rapid division. Lipid metabolism in T-cell cancer provides molecules having immunosuppressive abilities. Moreover, the distinctive composition of membrane lipids has implications for immune evasion by malignant cells of T-cell origin. Lipid droplets and lipid rafts are contributors to maintaining hallmarks of cancer in malignancies of T cells. In preclinical settings, molecular targeting of lipid metabolism in T-cell cancer potentiates the antitumor immunity and chemotherapeutic response. Thus, the direct and adjunct benefit of lipid metabolic targeting is expected to improve the clinical management of T-cell malignancies.

Zinc Finger MYND-Type Containing 8 (ZMYND8) Is Epigenetically Regulated in Mutant Isocitrate Dehydrogenase 1 (IDH1) Glioma to Promote Radioresistance

PURPOSE

Mutant isocitrate dehydrogenase 1 (mIDH1) alters the epigenetic regulation of chromatin, leading to a hypermethylation phenotype in adult glioma. This work focuses on identifying gene targets epigenetically dysregulated by mIDH1 to confer therapeutic resistance to ionizing radiation (IR).

EXPERIMENTAL DESIGN

We evaluated changes in the transcriptome and epigenome in a radioresistant mIDH1 patient-derived glioma cell culture (GCC) following treatment with an mIDH1-specific inhibitor, AGI-5198. We identified Zinc Finger MYND-Type Containing 8 (ZMYND8) as a potential target of mIDH1 reprogramming. We suppressed ZMYND8 expression by shRNA knockdown and genetic knockout (KO) in mIDH1 glioma cells and then assessed cellular viability to IR. We assessed the sensitivity of mIDH1 GCCS to pharmacologic inhibition of ZMYND8-interacting partners: HDAC, BRD4, and PARP.

RESULTS

Inhibition of mIDH1 leads to an upregulation of gene networks involved in replication stress. We found that the expression of ZMYND8, a regulator of DNA damage response, was decreased in three patient-derived mIDH1 GCCs after treatment with AGI-5198. Knockdown of ZMYND8 expression sensitized mIDH1 GCCs to radiotherapy marked by decreased cellular viability. Following IR, mIDH1 glioma cells with ZMYND8 KO exhibit significant phosphorylation of ATM and sustained γH2AX activation. ZMYND8 KO mIDH1 GCCs were further responsive to IR when treated with either BRD4 or HDAC inhibitors. PARP inhibition further enhanced the efficacy of radiotherapy in ZMYND8 KO mIDH1 glioma cells.

CONCLUSIONS

These findings indicate the impact of ZMYND8 in the maintenance of genomic integrity and repair of IR-induced DNA damage in mIDH1 glioma. See related commentary by Sachdev et al., p. 1648.

YAP-Activated SATB2 Is a Coactivator of NRF2 That Amplifies Antioxidative Capacity and Promotes Tumor Progression in Renal Cell Carcinoma

Aberrant epigenetic reprogramming contributes to the progression of renal cell carcinoma (RCC). Elucidation of key regulators of epigenetic reprogramming in RCC could help identify therapeutic vulnerabilities to improve treatment. Here, we report upregulation of the nuclear matrix-associated protein, special AT-rich binding protein-2 (SATB2), in RCC samples, which correlated with poor prognosis. SATB2 inhibition suppressed RCC growth and self-renewal capacities. YAP/TEAD4 activated SATB2 expression and depended on SATB2 to enhance cell proliferation. Transcriptome analysis implicated that SATB2 regulates NRF2 downstream targets to suppress oxidative stress without altering NRF2 levels. Integrated chromatin immunoprecipitation sequencing and assay for transposase-accessible chromatin using sequencing analyses demonstrated that SATB2 coordinated with NRF2 to drive enhancer-promoter interactions, amplifying transcriptional activity. SATB2 recruited SWI/SNF complex subunits, including BRD7 or BRG1, to sustain DNA accessibility. Increased SATB2 triggered chromatin remodeling into configurations that rendered RCC more sensitive to SATB2 deficiency. Moreover, SATB2 ablation promoted the sensitivity of RCC to chemotherapy-induced apoptosis. Finally, targeting SATB2 or BRD7 effectively restricted the proliferation of YAP-high tumors in patient-derived xenografts and patient-derived organoids. Together, SATB2 is an oncogenic chromatin organizer in RCC, and targeting SATB2 is an effective strategy to suppress the YAP-high RCC.

SIGNIFICANCE

A YAP-SATB2-NRF2 regulatory axis amplifies antioxidative stress signaling and provides potential therapeutic targets to enhance response to chemotherapy in renal cell carcinoma.

Zinc finger myeloid Nervy DEAF-1 type (ZMYND) domain containing proteins exert molecular interactions to implicate in carcinogenesis

Morphogenesis and organogenesis in the low organisms have been found to be modulated by a number of proteins, and one of such factor, deformed epidermal auto-regulatory factor-1 (DEAF-1) has been initially identified in Drosophila. The mammalian homologue of DEAF-1 and structurally related proteins have been identified, and they formed a family with over 20 members. The factors regulate gene expression through association with co-repressors, recognition of genomic marker, to exert histone modification by catalyze addition of some chemical groups to certain amino acid residues on histone and non-histone proteins, and degradation host proteins, so as to regulate cell cycle progression and execution of cell death. The formation of fused genes during chromosomal translocation, exemplified with myeloid transforming gene on chromosome 8 (MTG8)/eight-to-twenty one translocation (ETO) /ZMYND2, MTG receptor 1 (MTGR1)/ZMYND3, MTG on chromosome 16/MTGR2/ZMYND4 and BS69/ZMYND11 contributes to malignant transformation. Other anomaly like copy number variation (CNV) of BS69/ZMYND11 and promoter hyper methylation of BLU/ZMYND10 has been noted in malignancies. It has been reported that when fusing with Runt-related transcription factor 1 (RUNX1), the binding of MTG8/ZMYND2 with co-repressors is disturbed, and silencing of BLU/ZMYND10 abrogates its ability to inhibition of cell cycle and promotion of apoptotic death. Further characterization of the implication of ZMYND proteins in carcinogenesis would enhance understanding of the mechanisms of occurrence and early diagnosis of tumors, and effective antitumor efficacy.

Deubiquitinase USP35 stabilizes BRPF1 to activate mevalonate (MVA) metabolism during prostate tumorigenesis

The mutual interplay between epigenetic modifications and metabolic rewiring contributes to malignant features of prostate adenocarcinoma (PRAD). This study aimed to uncover the biological roles of deubiquitylase USP35 in PRAD and find effective epigenetic or metabolic targets. Bioinformatic tools or methods revealed that USP35 is upregulated in PRAD samples and correlates with inferior prognosis. The in vitro and in vivo assays suggested that USP35 could enhance malignant features of PRAD cells. Mechanistically, we found that USP35 could directly deubiquitinate and stabilize BRPF1 proteins. USP35 depends on accumulated BRPF1 proteins to accelerate cell growth, stem-like properties, and migration in vitro and in vivo. Interestingly, high BRPF1 could bind to promoter of SREBP2 and activate the SREBP2 transcriptional capacity. Therefore, USP35/BRPF1 aixs could promote expressions of mevalonate (MVA) metabolism signature in a SREBP2-dependent manner. USP35 depends on BRPF1 to maintain the activity of mevalonate metabolism in PRAD cells. Last of all, we observed that targeting BRPF1 or using MVA inhibitor (atorvastatin) are effective to suppress USP35high PRAD in vivo tumor growth. USP35 is an indicator of MVA metabolic signature in PRAD. Collectively, our study highlighted the USP35/BRPF1/SREBP2 axis in modulating MVA metabolism in PRAD, suggesting the significance of BRPF1 or MVA as the potential therapeutic targets for PRAD treatment.

KIF11 manipulates SREBP2-dependent mevalonate cross talk to promote tumor progression in pancreatic ductal adenocarcinoma

Cholesterol metabolism is highly correlated with risks of pancreatic ductal adenocarcinoma (PDAC). Nevertheless, the underlying mechanisms of activation of cholesterol biogenesis remain inconclusive. KIF11 is a key component of the bipolar spindle and expresses highly in various malignancies. However, its functional role in PDAC tumorigenesis is still unclear. This study aims to elucidate the oncogenic functions of KIF11 in stimulating cholesterol metabolism, thereby driving PDAC progression. We utilized bioinformatics analysis to identify that KIF11 expressed highly in tumor samples versus paired normal tissues and high KIF11 correlated with high clinical stages of patients. Patients with high KIF11 had worse survival outcomes relative to those with low KIF11. Gene set enrichment analysis (GSEA) revealed that KIF11 correlated intensively with the mevalonate (MVA) metabolic pathway. Positive associations were observed between KIF11 and MVA-signature (HMGCR, FDFT1, SQLE, and MSMO1). KIF11 could elevate the free cholesterol content of PDAC cells and targeting MVA inhibited the in vitro growth of KIF11-overexpressing cells. Mechanistically, we found KIF11 could interact with SREBP2, the master regulator of MVA. High KIF11 could increase SREBP2 proteins, but not alter their mRNA levels. KIF11 could attenuate the ubiquitination-mediated degradation of SREBP2, thereby enhancing its stability and accumulation. Accordingly, KIF11 stimulated the expressions of MVA-signature and free cholesterol contents depending on SREBP2. In addition, KIF11 depended on SREBP2 to promote cell growth, migration, stemness, and colony formation abilities. The subcutaneous xenograft models indicated that targeting MVA biogenesis (atorvastatin) is effective to restrict the in vivo growth of KIF11high PDAC. Taken together, our study identified that KIF11 could activate the MVA cross talk to drive PDAC progression and inhibiting the KIF11/MVA axis provided a therapeutic vulnerability in the treatment of PDAC.

ZMYND8 is a master regulator of 27-hydroxycholesterol that promotes tumorigenicity of breast cancer stem cells

27-Hydroxycholesterol (27-HC) is the most abundant oxysterol that increases the risk of breast cancer progression. However, little is known about epigenetic regulation of 27-HC metabolism and its role in breast tumor initiation. Using genetic mouse mammary tumor and human breast cancer models, we showed here that the histone reader ZMYND8 was selectively expressed in breast cancer stem cells (BCSCs) and promoted epithelial-mesenchymal transition (EMT), BCSC maintenance and self-renewal, and oncogenic transformation through its epigenetic functions, leading to breast tumor initiation. Mechanistically, ZMYND8 was a master transcriptional regulator of 27-HC metabolism. It increased cholesterol biosynthesis and oxidation but blocked cholesterol efflux and 27-HC catabolism, leading to accumulation of 27-HC in BCSCs. Consequently, 27-HC promoted EMT, oncogenic transformation, and tumor initiation through activation of liver X receptor. These findings reveal that ZMYND8 is an epigenetic booster that drives breast tumor initiation through metabolic reprogramming.

YAP regulates an SGK1/mTORC1/SREBP-dependent lipogenic program to support proliferation and tissue growth

The coordinated regulation of growth control and metabolic pathways is required to meet the energetic and biosynthetic demands associated with proliferation. Emerging evidence suggests that the Hippo pathway effector Yes-associated protein 1 (YAP) reprograms cellular metabolism to meet the anabolic demands of growth, although the mechanisms involved are poorly understood. Here, we demonstrate that YAP co-opts the sterol regulatory element-binding protein (SREBP)-dependent lipogenic program to facilitate proliferation and tissue growth. Mechanistically, YAP stimulates de novo lipogenesis via mechanistic target of rapamcyin (mTOR) complex 1 (mTORC1) signaling and subsequent activation of SREBP. Importantly, YAP-dependent regulation of serum- and glucocorticoid-regulated kinase 1 (SGK1) is required to activate mTORC1/SREBP and stimulate de novo lipogenesis. We also find that the SREBP target genes fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD) are conditionally required to support YAP-dependent proliferation and tissue growth. These studies reveal that de novo lipogenesis is a metabolic vulnerability that can be targeted to disrupt YAP-dependent proliferation and tissue growth.

Emerging Principles in the Transcriptional Control by YAP and TAZ

Simple Summary

YAP and TAZ are transcriptional cofactors that integrate several upstream signals to generate context-dependent transcriptional responses. This requires extensive integration with epigenetic regulators and other transcription factors. The molecular and genomic characterization of YAP and TAZ nuclear function has broad implications both in physiological and pathological settings.

Abstract

Yes-associated protein (YAP) and TAZ are transcriptional cofactors that sit at the crossroad of several signaling pathways involved in cell growth and differentiation. As such, they play essential functions during embryonic development, regeneration, and, once deregulated, in cancer progression. In this review, we will revise the current literature and provide an overview of how YAP/TAZ control transcription. We will focus on data concerning the modulation of the basal transcriptional machinery, their ability to epigenetically remodel the enhancer–promoter landscape, and the mechanisms used to integrate transcriptional cues from multiple pathways. This reveals how YAP/TAZ activation in cancer cells leads to extensive transcriptional control that spans several hallmarks of cancer. The definition of the molecular mechanism of transcriptional control and the identification of the pathways regulated by YAP/TAZ may provide therapeutic opportunities for the effective treatment of YAP/TAZ-driven tumors.