ING4 and ING5 are essential for histone H3 lysine 14 acetylation and epicardial cell lineage development.

Inhibitor of growth 4 and 5 (ING4, ING5) are structurally similar chromatin-binding proteins in the KAT6A, KAT6B and KAT7 histone acetyltransferase protein complexes. Heterozygous mutations in the KAT6A or KAT6B gene cause human disorders with cardiac defects, but the contribution of their chromatin-adaptor proteins to development is unknown. We found that Ing5-/- mice had isolated cardiac ventricular septal defects. Ing4-/-Ing5-/- embryos failed to undergo chorioallantoic fusion and arrested in development at embryonic day 8.5, displaying loss of histone H3 lysine 14 acetylation, reduction in H3 lysine 23 acetylation levels and reduced developmental gene expression. Embryonic day 12.5 Ing4+/-Ing5-/- hearts showed a paucity of epicardial cells and epicardium-derived cells, failure of myocardium compaction, and coronary vasculature defects, accompanied by reduced expression of epicardium genes. Cell adhesion gene expression and proepicardium outgrowth were defective in the ING4- and ING5-deficient state. Our findings suggest that ING4 and ING5 are essential for heart development and promote epicardium and epicardium-derived cell fates and imply mutation of the human ING5 gene as a possible cause of isolated ventricular septal defects.

Tctp, a unique Ing5-binding partner, inhibits the chromatin binding of Enok in Drosophila.

The MOZ/MORF histone acetyltransferase complex is highly conserved in eukaryotes and controls transcription, development, and tumorigenesis. However, little is known about how its chromatin localization is regulated. Inhibitor of growth 5 (ING5) tumor suppressor is a subunit of the MOZ/MORF complex. Nevertheless, the in vivo function of ING5 remains unclear. Here, we report an antagonistic interaction between Drosophila Translationally controlled tumor protein (TCTP) (Tctp) and ING5 (Ing5) required for chromatin localization of the MOZ/MORF (Enok) complex and H3K23 acetylation. Yeast two-hybrid screening using Tctp identified Ing5 as a unique binding partner. In vivo, Ing5 controlled differentiation and down-regulated epidermal growth factor receptor signaling, whereas it is required in the Yorkie (Yki) pathway to determine organ size. Ing5 and Enok mutants promoted tumor-like tissue overgrowth when combined with uncontrolled Yki activity. Tctp depletion rescued the abnormal phenotypes of the Ing5 mutation and increased the nuclear translocation of Ing5 and chromatin binding of Enok. Nonfunctional Enok promoted the nuclear translocation of Ing5 by reducing Tctp, indicating a feedback mechanism between Tctp, Ing5, and Enok to regulate histone acetylation. Therefore, Tctp is essential for H3K23 acetylation by controlling the nuclear translocation of Ing5 and chromatin localization of Enok, providing insights into the roles of human TCTP and ING5-MOZ/MORF in tumorigenesis.

A synthetic lethality screen reveals ING5 as a genetic dependency of catalytically dead Set1A/COMPASS in mouse embryonic stem cells.

Embryonic stem cells (ESCs) are defined by their ability to self-renew and the potential to differentiate into all tissues of the developing organism. We previously demonstrated that deleting the catalytic SET domain of the Set1A/complex of proteins associated with SET1 histone methyltransferase (Set1A/COMPASS) in mouse ESCs does not impair their viability or ability to self-renew; however, it leads to defects in differentiation. The precise mechanisms by which Set1A executes these functions remain to be elucidated. In this study, we demonstrate that mice lacking the SET domain of Set1A are embryonic lethal at a stage that is unique from null alleles. To gain insight into Set1A function in regulating pluripotency, we conducted a CRISPR/Cas9-mediated dropout screen and identified the MOZ/MORF (monocytic leukaemia zinc finger protein/monocytic leukaemia zinc finger protein-related factor) and HBO1 (HAT bound to ORC1) acetyltransferase complex member ING5 as a synthetic perturbation to Set1A. The loss of Ing5 in Set1AΔSET mouse ESCs decreases the fitness of these cells, and the simultaneous loss of ING5 and in Set1AΔSET leads to up-regulation of differentiation-associated genes. Taken together, our results point toward Set1A/COMPASS and ING5 as potential coregulators of the self-renewal and differentiation status of ESCs.

Mechanism of non-small cell lung cancer cell-derived exosome miR-196b-5p promoting pyroptosis of tumor T cells and tumor cell proliferation by downregulating ING5.

In the world, lung cancer is one of the most common malignant cancers and has become the leading cause of death of cancers in China, among which non-small cell lung cancer (NSCLC) accounts for a relatively high proportion, but there is a lack of effective treatment at present. An animal model of NSCLC was established, and BEAS-2b, H1299, Lewis, and T cells were used for subsequent experimental verification. The level of miR-196b-5p was detected by quantitative real-time polymerase chain reaction. Growth inhibitor 5 (ING5), CD9, CD63, HSP70, Caspase-1, NLRP3, and GSDMD-NT were detected by western blot. The level of ING5 was confirmed by immunohistochemistry, the location of miR-196b-5p was analyzed by fluorescence in situ hybridization (FISH), cell viability was investigated by Cell Counting Kit-8 kit, and interleukin (IL)-1ß and IL-18 were confirmed by enzyme-linked immunosorbent assay. Cell apoptosis was detected by flow cytometry. In addition, the binding site was verified by dual-luciferase reporter gene experiments. Tumor volume was measured. TUNEL staining was used to detect apoptosis. Flow cytometry was used to measure the levels of CD8 T, CD4 T, and Treg cells in tumors. miR-196-5p was highly expressed in exosomes secreted by tumor cells. miR-196-5p negatively targeted ING5 to promote the growth of tumor cells. Cancer-derived exosomes promote pyroptosis of T cells to further aggravate the development of cancer. Exosome-derived miR-196b-5p promoted pyroptosis of T cells. Exosome-derived miR-196b-5p inhibited the level of ING5 to promote tumor growth and accelerate the process of NSCLC.

Hepatitis E virus infection upregulates ING5 expression in vitro and in vivo.

Hepatitis E virus (HEV) is the major pathogen of viral hepatitis. Immunocompromised individuals infected by HEV are prone to chronic hepatitis and increase the risk of hepato-cellular carcinoma (HCC). Inhibitor of growth family member 5 (ING5) is a tumor suppressor that is expressed at low levels in cancer tumors or cells. However, the underlying relationship between ING5 and HEV infection is unclear. In the present study, acute and chronic HEV animal models are used to explore the interaction between ING5 and HEV. Notably, the expression of ING5 is significantly increased in both the livers of acute HEV-infected BALB/c mice and chronic HEV-infected rhesus macaques. In addition, the relationship between HEV infection and ING5 expression is further identified in human hepatoma (HepG-2) cells. In conclusion, HEV infection strongly upregulates ING5 expression both in vivo and in vitro, which has significant implications for further understanding the pathogenic mechanism of HEV infection.

SCFJFK is functionally linked to obesity and metabolic syndrome.

Dysregulation of lipid metabolism could lead to the development of metabolic disorders. We report here that the F-box protein JFK promotes excessive lipid accumulation in adipose tissue and contributes to the development of metabolic syndrome. JFK transgenic mice develop spontaneous obesity, accompanied by dyslipidemia, hyperglycemia, and insulin resistance, phenotypes that are further exacerbated under high-fat diets. In contrast, Jfk knockout mice are lean and resistant to diet-induced metabolic malfunctions. Liver-specific reconstitution of JFK expression in Jfk knockout mice leads to hepatic lipid accumulation resembling human hepatic steatosis and nonalcoholic fatty liver disease. We show that JFK interacts with and destabilizes ING5 through assembly of the SCF complex. Integrative transcriptomic and genomic analysis reveals that the SCFJFK -ING5 axis interferes with AMPK activity and fatty acid ß-oxidation, leading to the suppression of hepatic lipid catabolism. Significantly, JFK is upregulated and AMPKα1 is down-regulated in liver tissues from NAFLD patients. These results reveal that SCFJFK is a bona fide E3 ligase for ING5 and link the SCFJFK -ING5 axis to the development of obesity and metabolic syndrome.

ING5 overexpression upregulates miR-34c-5p/Snail1 to inhibit EMT and invasion of lung cancer cells.

ING5 belongs to the inhibitor of growth (ING) candidate tumor suppressor family, which is involved in multiple cellular functions, such as cell cycle regulation, apoptosis, and chromatin remodelling. Previously, we reported that ING5 overexpression inhibits EMT by regulating EMT-related molecules, including Snail1, at the mRNA and protein levels. However, the mechanisms remain unclear. In the current study, we identify that ING5 overexpression induces the upregulation of miR-34c-5p. The expression levels of both ING5 and miR-34c-5p in NSCLC tissues from the TCGA database are decreased compared with that in adjacent tissues. Higher expression levels of both ING5 and miR-34c-5p predict longer overall survival (OS). Snail1 is the target gene of miR-34c-5p, as predicted by an online database, which is further verified by a dual-luciferase reporter assay. The expression level of Snail1 in NSCLC cells is markedly reduced following miR-34c-5p overexpression, leading to the inactivation of the Snail1 downstream TGF-ß/Smad3 signaling pathway. The TGF-ß signaling-specific inhibitor LY2157299 reverses the enhanced EMT, proliferation, migration, and invasion abilities induced by the miR-34c-5p inhibitor. Furthermore, tail vein injection of miR-34c-5p agomir inhibits xenografted tumor metastasis. Overall, this study concludes that miR-34c-5p, induced by ING5 overexpression, is a tumor suppressor that targets Snail1 and mediates the inhibitory effects of ING5 on the EMT and invasion of NSCLC cells. These results provide a novel mechanism mediating the antitumor effects of ING5.

Hsa_circ_0010729 is Involved in Oxygen-Glucose Deprivation/Reoxygenation-Induced Human Microvascular Endothelial Cell Deprivation by Targeting miR-665/ING5.

Ischemic stroke is a disease with high mortality. Circular RNA_0010729 (hsa_circ_0010729) has been reported to be involved in ischemic heart disease. However, it is not clear whether hsa_circ_0010729 is involved in the regulation of ischemic stroke. In this study, we used oxygen-glucose deprivation/reoxygenation (OGD/R) to stimulate human brain microvascular endothelial cells (HBMECs) model to investigate the potential role of hsa_circ_0010729 in stroke in vitro. The expression levels of hsa_circ_0010729, miR-665, and ING5 in ischemic stroke were detected by quantitative real-time polymerase chain reaction (qRT-PCR). HBMECs proliferation was detected by CCK-8. Cell apoptosis was detected by flow cytometry. The levels of inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Western blot was used to detect the related protein expression. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) were used to examine the target relationship between miR-665 and hsa_circ_0010729 or ING5. Compared with the control group, hsa_circ_0010729 and ING5 were highly expressed in OGD/R-induced HBMECs, while miR-665 was lowly expressed. Hsa_circ_0010729 silencing promoted OGD/R-induced cell proliferation and inhibited apoptosis. However, the effect of hsa_circ_0010729 down-regulation on OGD/R-induced cell was partially restored after co-transfection with miR-665 inhibitor. Overexpression of miR-665 can promote the proliferation and inhibit apoptosis of OGD/R-induced HBMECs by inhibiting ING5 expression. In OGD/R-induced HBMECs, hsa_circ_0010729 silencing decreased ING5 expression by upregulating miR-665. Hsa_circ_0010729 regulated miR-665/ING5 axis in OGD/R-induced HBMECs. Therefore, hsa_circ_0010729 may be a new therapeutic target for ischemic stroke.

MicroRNA-196b-5p promotes malignant progression of colorectal cancer by targeting ING5.

BACKGROUND: miR-196b-5p expression is deregulated in many malignant tumors. Although miR-196b-5p has been implicated in the malignant transformation of colorectal cancer, its role in this specific type of cancer has not been fully explored. Thus, the present study was aimed to examine the cellular function of miR-196b-5p and its role in malignant biological behavior in colorectal cancer. METHODS: miR-196b-5p expression was measured in colorectal cancer tissues and cell lines using quantitative real-time PCR. Cell counting kit-8 (CCK-8) assay and Transwell assay were used to detect proliferation, migration, and invasion in cell lines, whereas flow cytometry was applied to study apoptosis. Western blot analysis was performed to measure the protein levels. Dual luciferase reporter assay was used to investigate the interaction between miR-196b-5p and ING5. Tumor formation was evaluated in mice. RESULTS: MiR-196b-5p was abundantly expressed in colorectal cancer tissues and cell lines, whereas ING5 was expressed at low levels. MiR-196b-5p was successfully overexpressed or knocked down in colorectal cancer cells. We found that miR-196b-5p overexpression significantly accelerated the proliferation, cell cycle, migration and invasion, while inhibited cell apoptosis in colorectal cancer cells. However, miR-196b-5p inhibitor showed the opposite effects. Moreover, ING5 overexpression or knockdown was successfully performed in colorectal cancer cells. ING5 overexpression suppressed proliferation, migration, invasion, the phosphorylation of PI3K, Akt as well as MEK, and promoted cell apoptosis, which could be reversed by ING5 knockdown. Additionally, ING5 was identified as a target of miR-196b-5p through bioinformatics analysis and a luciferase activity assay. Furthermore, ING5 knockdown could attenuate the decrease in proliferation, migration, invasion, and the protein levels of p-PI3K, p-Akt, and p-MEK, which were induced by miRNA-196b-5p inhibitor. Besides, miR-196b-5p knockdown inhibited tumor growth, whereas ING5 knockdown elevated it in vivo. CONCLUSIONS: In conclusion, miR-196b-5p promotes cell proliferation, migration, invasion, and inhibits apoptosis in colorectal cancer by targeting ING5.

ING5 inhibits cancer aggressiveness by inhibiting Akt and activating p53 in prostate cancer.

Prostate cancer (PCa) is one of the most common types of cancer in men. In several recent studies, chromosomal deletions in the q arm of chromosome 2, where ING5 resides within, have been identified in various cancer types including PCa. In this study, we investigate the role of ING5 as a tumor suppressor in PCa. We examined the expression level of ING5 in tissue samples and cell lines using quantitative real-time polymerase chain reaction and western blot analysis. We tested the in vitro tumor suppressor potential of ING5 in PC3 and LNCaP cells stably overexpressing it using cell viability, colony formation, migration, invasion, and apoptosis assays. We then investigated the effects of ING5 on the Akt and p53 signaling using western blot analysis. We show that ING5 is significantly downregulated in PCa tumor tissue samples and cell lines compared with the corresponding controls. In vitro assays demonstrate that ING5 effectively suppresses proliferative, clonogenic, migratory, and invasive potential and induce apoptosis in PCa cells. ING5 may potentially exert its anti-tumor potential by inhibiting AKT and inducing p53 signaling pathways. Our findings demonstrate that ING5 possesses tumor suppressor roles in vitro, pointing its importance during the prostatic carcinogenesis processes.

LncRNA CASC2 inhibits hypoxia-induced pulmonary artery smooth muscle cell proliferation and migration by regulating the miR-222/ING5 axis.

BACKGROUND: Pulmonary arterial hypertension (PAH) is often characterized by cell proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). LncRNA cancer susceptibility candidate 2 (CASC2) has been revealed to be involved in PASMC injury in hypoxia-induced pulmonary hypertension. However, the exact molecular mechanisms whereby CASC2 regulates PASMC proliferation and migration are still incompletely understood. METHODS: The expression levels of CASC2, miR-222 and inhibitor of growth 5 (ING5) were measured using quantitative real-time polymerase chain reaction (qRT-PCR) or western blot, respectively. Cell proliferation was analyzed by Cell Counting Kit-8 (CCK-8) assay. Wound healing assay was used to analyze cell migration ability. The relationship between miR-222 and CASC2 or ING5 was confirmed using bioinformatics analysis, luciferase reporter assay and RNA immunoprecipitation assay. RESULTS: CASC2 was down-regulated in hypoxia-induced PASMCs in a dose- and time-dependent manner. Functional experiments showed that CASC2 overexpression could reverse hypoxia-induced proliferation and migration of PASMCs. Bioinformatics analysis indicated that CASC2 acted as a competing endogenous RNA of miR-222, thereby regulating the expression of ING5, the downstream target of miR-222, in PASMCs. In addition, rescue assay suggested that the inhibition mediated by CASC2 of hypoxia-induced PASMC proliferation and migration could be attenuated by miR-222 inhibition or ING5 overexpression. CONCLUSION: CASC2 attenuated hypoxia-induced PASMC proliferation and migration by regulating the miR-222/ING5 axis to prevent vascular remodeling and the development of PAH, providing a novel insight and therapeutic strategy for hypoxia-induced PAH.

Long noncoding RNA UCA1 promotes the proliferation of hypoxic human pulmonary artery smooth muscle cells.

Our study explored the effects of lncRNA UCA1 on the proliferation and apoptosis in hypoxic human pulmonary artery smooth muscle cells (HPASMCs) and highlighted the endogenous relationship between UCA1, ING5, and hnRNP I in cell proliferation. Hypoxia-induced HPASMCs were used to simulate pulmonary arterial hypertension in vitro. Microarray assay was adopted to screen the dysregulated expressed lncRNAs in HPASMCs to find out the target gene of our study. And RT-qPCR was performed to detect the expression of lncRNA UCA1 under hypoxia and normoxia. After transfection, the relationship between UCA1 and cell proliferation in HPASMCs under hypoxia were determined by cell proliferation assay and relative expression of PCNA. Next, ELISA assays were conducted to measure the protein levels of PCNA and ING5. What's more, flow cytometry was employed to measure the apoptosis rate in differentially UCA1-expressed HPASMCs. RIP assays were conducted to further clarify the endogenous relationship between UCA1 and ING5 in hypoxic HPASMCs. Finally, the effects of ING5 to HPASMCs were detected after transfection of ING5 and UCA1 to figure out the role of ING5 in HPASMCs. Hypoxia was revealed to induce proliferation and inhibited apoptosis in HPASMCs. Besides, UCA1 was confirmed to be highly expressed under hypoxia compared with normoxia. UCA1 boosted cell proliferation under hypoxia in HPASMCs. However, the apoptosis was suppressed in the hypoxic HPASMCs transfected with pcDNA3.1-UCA1. Further, mechanism studies found that UCA1 competed with ING5 for hnRNP I, so that upregulating UCA1 inhibited the protein levels of ING5. And finally we found that ING5 restrained cell viability, but promoted cell apoptosis in hypoxic HPASMCs, which was reversed by UCA1 over-expression. In summary, our findings manifested that UCA1 promoted proliferation and restrained apoptosis by competing with ING5 for hnRNP I in HPASMCs induced by hypoxia, indicating their potential roles for the cure of hypoxic pulmonary hypertension.

Upregulation of miR-376c-3p alleviates oxygen-glucose deprivation-induced cell injury by targeting ING5.

BACKGROUND: The expression level of miR-376c-3p is significantly lower in infants with neonatal hypoxic-ischemic encephalopathy (HIE) than in healthy infants. However, the biological function of this microRNA remains largely elusive. METHODS: We used PC-12 and SH-SY5Y cells to establish an oxygen-glucose deprivation (OGD) cell injury model to mimic HIE in vitro. The miR-376c-3p expression levels were measured using quantitative reverse transcription PCR. The CCK-8 assay and flow cytometry were utilized to evaluate OGD-induced cell injury. The association between miR-376c-3p and inhibitor of growth 5 (ING5) was validated using the luciferase reporter assay. Western blotting was conducted to determine the protein expression of CDK4, cyclin D1, Bcl-2 and Bax. RESULTS: MiR-376c-3p was significantly downregulated in the OGD-induced cell injury model. Its overexpression elevated cell viability and impaired cell cycle G0/G1 phase arrest and apoptosis in PC-12 and SH-SY5Y cells after OGD. Downregulation of miR-376c-3p gave the opposite results. We further demonstrated that ING5 was a negatively regulated target gene of miR-376c-3p. Importantly, ING5 knockdown had a similar effect to miR-376c-3p-mediated protective effects against cell injury induced by OGD. Its overexpression abolished these protective effects. CONCLUSION: Our data suggest that miR-376c-3p downregulated ING5 to exert protective effects against OGD-induced cell injury in PC-12 and SH-SY5Y cells. This might represent a novel therapeutic approach for neonatal HIE treatment.

ING5 inhibits cell proliferation and invasion in esophageal squamous cell carcinoma through regulation of the Akt/NF-κB/MMP-9 signaling pathway.

The inhibitor of growth 5 (ING5) is a new candidate tumor suppressor gene (TSG) of the ING family. So far, there have been many reports about its functions related to cancer development. However, the biological roles of ING5 in esophageal squamous cell carcinoma (ESCC) remain unclear. In the present study, we demonstrated that ING5 was lowly expressed in ESCC tissues and cell lines. Overexpression of ING5 inhibited ESCC cell proliferation and invasion in vitro as well as suppressed tumor growth and metastasis in vivo. We also found that overexpression of ING5 significantly decreased the levels of p-AKT, NF-κB and MMP-9 in ECA109 cells. Taken together, these findings demonstrated that ING5 inhibited cell proliferation and invasion in ESCC through regulation of the Akt/NF-κB/MMP-9 signaling pathway. Thus, ING5 might be considered a promising target for ESCC treatment.

Hepatitis B virus X protein promotes proliferation of hepatocellular carcinoma cells by upregulating miR-181b by targeting ING5.

Hepatitis B virus X protein (HBx) played a key role in the development of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Emerging evidence has demonstrated that miR-181b and the inhibitor of growth protein 5 (ING5) participated in the pathophysiological process. However, the regulatory mechanism of HBx remained unknown. The expression of miR-181b and ING5 in HCC tissues and cell lines were examined using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Cell viability was determined using the MTT method following HCC cell lines transfection. The interaction between miR-181b and ING5 was assessed by luciferase reporter assay. The nude mice tumor model was well established to evaluate the role and biological functions of HBx on the progression of HBV-related HCC in vivo. MiR-181b was upregulated and ING5 was downregulated in HCC tissues and cell lines. As suggested by the results from in vitro and in vivo experiments, HBx downregulates the expression of the miR-181b target gene ING5, resulting in the promotion of HCC cell proliferation. HBx accelerates proliferation activity of HCC cells by increasing miR-181b expression via targeting ING5, thereby influencing the progression of HBV-related HCC.

ING5 suppresses breast cancer progression and is regulated by miR-24.

BACKGROUND: The inhibitor of growth (ING) gene family of tumor suppressors is involved in multiple cellular functions such as cell cycle regulation, apoptosis, and chromatin remodeling. ING5 is a new member of the ING family whose function and regulation remain largely unknown. METHODS: Quantitative real-time PCR and western blot were used to examine the expression levels of ING5 in breast cancer tissues. The miRNAs that potentially targeted ING5 were determined by bioinformatics analysis and luciferase reporter assay. Cell viability assay, transwell invasion and apoptosis assay were used to characterize the changes induced by overexpressing or knocking down miR-24 or ING5. Hematoxylin and eosin (H&E) staining and immunohistochemical staining for ING5 and Ki-67 were used for xenograft assays in BALB/c nude mice. RESULTS: We showed that the ING5 protein rather than the mRNA, was significantly downregulated in breast cancer tissues. We also investigated the potential function of ING5 in breast tumorigenesis and found that ING5 suppressed the proliferation and invasion of breast cancer cells and promoted their apoptosis. Furthermore, we explored the molecular mechanisms accounting for the dysregulation of ING5 in breast cancer cells and identified an oncomiR, miR-24, as a direct upstream regulator of ING5. We revealed that miR-24 had the opposite effects to those of ING5 on breast cancer cells and could accelerate xenografted tumor growth in vivo. CONCLUSION: Our findings uncover the tumor-suppressive role of ING5 and the regulatory pathway of ING5 in breast cancer and may provide insights into the molecular mechanisms of breast carcinogenesis.

Copy number variants in a population-based investigation of Klippel-Trenaunay syndrome.

Klippel-Trenaunay syndrome (KTS) is a rare congenital vascular disorder that is thought to occur sporadically; however, reports of familial occurrence suggest a genetic component. We examined KTS cases to identify novel, potentially causal copy number variants (CNVs). We identified 17 KTS cases from all live-births occurring in New York (1998-2010). Extracted DNA was genotyped using Illumina microarrays and CNVs were called using PennCNV software. CNVs selected for follow-up had ≥10 single nucleotide polymorphisms (SNPs) and minimal overlap with in-house controls or controls from the Database of Genomic Variants. We identified 15 candidate CNVs in seven cases; among them a deletion in two cases within transcripts of HDAC9, a histone deacetylase essential for angiogenic sprouting of endothelial cells. One of them also had a duplication upstream of SALL3, a transcription factor essential for embryonic development that inhibits DNMT3A, a DNA methyltransferase responsible for embryonic de novo DNA methylation. Another case had a duplication spanning ING5, a histone acetylation regulator active during embryogenesis. We identified rare genetic variants related to chromatin modification which may have a key role in regulating vascular development during embryogenesis. Further investigation of their implications in the pathogenesis of KTS is warranted. © 2016 Wiley Periodicals, Inc.

MOZ and MORF acetyltransferases: Molecular interaction, animal development and human disease.

Lysine residues are subject to many forms of covalent modification and one such modification is acetylation of the ε-amino group. Initially identified on histone proteins in the 1960s, lysine acetylation is now considered as an important form of post-translational modification that rivals phosphorylation. However, only about a dozen of human lysine acetyltransferases have been identified. Among them are MOZ (monocytic leukemia zinc finger protein; a.k.a. MYST3 and KAT6A) and its paralog MORF (a.k.a. MYST4 and KAT6B). Although there is a distantly related protein in Drosophila and sea urchin, these two enzymes are vertebrate-specific. They form tetrameric complexes with BRPF1 (bromodomain- and PHD finger-containing protein 1) and two small non-catalytic subunits. These two acetyltransferases and BRPF1 play key roles in various developmental processes; for example, they are important for development of hematopoietic and neural stem cells. The human KAT6A and KAT6B genes are recurrently mutated in leukemia, non-hematologic malignancies, and multiple developmental disorders displaying intellectual disability and various other abnormalities. In addition, the BRPF1 gene is mutated in childhood leukemia and adult medulloblastoma. Therefore, these two acetyltransferases and their partner BRPF1 are important in animal development and human disease.

Symplekin, a polyadenylation factor, prevents MOZ and MLL activity on HOXA9 in hematopoietic cells.

MOZ and MLL encoding a histone acetyltransferase and a histone methyltransferase, respectively, are targets for recurrent chromosomal translocations found in acute myeloblastic or lymphoblastic leukemia. We have previously shown that MOZ and MLL cooperate to activate HOXA9 gene expression in hematopoietic stem/progenitors cells. To dissect the mechanism of action of this complex, we decided to identify new proteins interacting with MOZ. We found that the scaffold protein Symplekin that supports the assembly of polyadenylation machinery was identified by mass spectrometry. Symplekin interacts and co-localizes with both MOZ and MLL in immature hematopoietic cells. Its inhibition leads to a decrease of the HOXA9 protein level but not of Hoxa9 mRNA and to an over-recruitment of MOZ and MLL onto the HOXA9 promoter. Altogether, our results highlight the role of Symplekin in transcription repression involving a regulatory network between MOZ, MLL and Symplekin.

ING5 inhibits aerobic glycolysis of lung cancer cells by promoting TIE1-mediated phosphorylation of pyruvate dehydrogenase kinase 1 at Y163.

Aerobic glycolysis is critical for tumor growth and metastasis. Previously, we have found that the overexpression of the inhibitor of growth 5 (ING5) inhibits lung cancer aggressiveness and epithelial-mesenchymal transition (EMT). However, whether ING5 regulates lung cancer metabolism reprogramming remains unknown. Here, by quantitative proteomics, we showed that ING5 differentially regulates protein phosphorylation and identified a new site (Y163) of the key glycolytic enzyme PDK1 whose phosphorylation was upregulated 13.847-fold. By clinical study, decreased p-PDK1Y163 was observed in lung cancer tissues and correlated with poor survival. p-PDK1Y163 represents the negative regulatory mechanism of PDK1 by causing PDHA1 dephosphorylation and activation, leading to switching from glycolysis to oxidative phosphorylation, with increasing oxygen consumption and decreasing lactate production. These effects could be impaired by PDK1Y163F mutation, which also impaired the inhibitory effects of ING5 on cancer cell EMT and invasiveness. Mouse xenograft models confirmed the indispensable role of p-PDK1Y163 in ING5-inhibited tumor growth and metastasis. By siRNA screening, ING5-upregulated TIE1 was identified as the upstream tyrosine protein kinase targeting PDK1Y163. TIE1 knockdown induced the dephosphorylation of PDK1Y163 and increased the migration and invasion of lung cancer cells. Collectively, ING5 overexpression-upregulated TIE1 phosphorylates PDK1Y163, which is critical for the inhibition of aerobic glycolysis and invasiveness of lung cancer cells.