High Mobility Group Nucleosomal Binding Domain 2 Research Articles

OR27-06 Identification And Functional Analyses Of Therapeutic Targets For Testicular Germ Cell Tumors

Abstract Disclosure: K. Horie: None. S. Kitayama: None. K. Ikeda: None. T. Suzuki: None. S. Kawakami: None. S. Inoue: None. Testicular germ cell tumor (TGCT) is the most common cancer among adolescent and young adult males. While cisplatin is a key drug that efficiently reduces TGCT growth, the acquisition of drug resistance is often life-threatening. To elucidate molecular mechanisms underlying the pathophysiology of TGCT, we established patient-derived TGCT spheroid cultures from nonseminomatous tumors, in which cancer stem cell population can be preferentially enriched. The TGCT spheroid cultures can be applied to the generation of in vivo xenograft models, which successfully recapitulated the pathological features of patient tumors with microenvironment. Transcriptomic analysis revealed that hypoxia-related genes were upregulated in TGCT spheroid cultures, and HIF1α inhibitor 2-methoxyestradiol could substantially repress the in vivo tumor formation. We further generated cisplatin-resistant TGCT models from embryonic cancer patient-derived spheroids and cell line, and found that transcription-related gene high mobility group nucleosome binding domain 5 (HMGN5) and meiosis-related gene testis-expressed 11 (TEX11) were remarkably upregulated in cisplatin-resistant TGCT cells compared with their parental cells. Either HMGN5 or TEX11 knockdown could reduce the viability of cisplatin-resistant TGCT cells in the presence of cisplatin. Of note, TEX11 knockdown increased cleaved PARP1 protein expression and the percentage of double-strand break marker γH2AX-positive cells in cisplatin-resistant TGCT cells. We demonstrated that siRNA-mediated TEX11 inhibition is a promising therapeutic option for cisplatin-resistant TGCT as we showed the efficacy in in vivo xenograft models generated from cisplatin-resistant patient-derived TGCT spheroids. Furthermore, chromatin immunoprecipitation sequencing for histone H3K27 acetylation status in the TGCT spheroid cultures revealed that the enrichment of “super-enhancers”, identified by the Rank Ordering of Super-enhancers algorithm [http://younglab.wi.mit.edu/super_enhancer_code.html], was well observed at chromosome 12p, where copy number gains are often observed in the tumors, and genes in the vicinity of super-enhancers identified in patient-derived TGCT models can be potential diagnostic and therapeutic targets for the advanced disease. Overall, the present study provides useful insights into the biology and chemoresistance of TGCT. Presentation: Saturday, June 17, 2023

HGG-24. A NOVEL ONCOGENIC ROLE FOR MENIN IN GLIOMA

Abstract High-grade gliomas (HGGs) represent the most common subtype of primary malignant tumors from brain or spinal cord. With about 18 months overall survival time, HGGs is the leading cause of death from primary brain tumor. Survival outcomes have not improved significantly over the past two decades despite major research and therapeutic discovery efforts. Previous work from our lab suggested a role for menin in initiation and maintenance of pediatric high-grade glioma. Here we describe a critical oncogenic role of menin (encoded by the MEN1 gene) in maintaining HGGs proliferation. Using a panel of early passage HGG lines harboring diverse genomic alterations, we demonstrate that silencing of MEN1 blocks proliferation (60%-80%) of a subset (8/12) of HGGs, independent of their genomic alteration profile. An oncogenic role of menin has been described in MLL-rearrangement leukemia, where menin complexes with MLL to affect H3K4 trimethylation and activate leukemogenic genes. However, we found that the menin-MLL interaction is not associated with glioma. Instead, our mechanistic studies suggest that menin plays a critical role in maintaining H3K27 acetylation marks across the genome. Using immunoprecipitation and mass spectrometry, we identified HMGN1 (high mobility group nucleosome-binding domain 1 protein) as a putative novel menin partner. HMGN1 is a chromatin remodeling protein associated with chromatin accessibility and H3K27 acetylation. Transcriptional studies of patient-derived HGGs revealed that knockout of MEN1 and silencing of HMGN1 both resulted in broad repression of genes associated with proliferative tumor progenitor clusters. Ongoing work is aimed at therapeutic targeting by novel menin inhibitors. Our work demonstrates the role of epigenetic remodeling in controlling glioma proliferation and identifying novel therapeutic targets.

Combining an Alarmin HMGN1 Peptide with PD-L1 Blockade Results in Robust Antitumor Effects with a Concomitant Increase of Stem-Like/Progenitor Exhausted CD8+ T Cells.

The expansion of intratumoral stem-like/progenitor exhausted CD8+ T (Tstem/Tpex) cells provides a potential approach to improve the therapeutic efficacy of immune checkpoint blockade (ICB). Thus, here we demonstrate a strategy to facilitate Tstem/Tpex cell expansion by combining an alarmin high-mobility group nucleosome binding domain 1 (HMGN1) peptide with programmed death-ligand 1 (PD-L1) blockade. The antitumor effects of HMGN1, anti-PD-L1, and their combined treatment were monitored in the B16F10, LLC, Colon26, or EO771 tumor-bearing mice. The comprehensive immunologic analyses, such as high-dimensional flow cytometry, transcriptome analysis, and single-cell RNA-sequencing (scRNA-seq), were used to investigate the cellular and molecular mechanisms of antitumor immune responses after treatments. We identified the immunostimulatory domain (EPKRR SARLS AKPPA KVEAK PKK) on HMGN1 and synthesized this domain as a therapeutic peptide (minP1). Combined treatment with minP1 and PD-L1 blockade induced durable tumor regression in tumor-bearing mice. minP1 increased the number of intratumoral mature DCs enriched in immunoregulatory molecules (mregDC) and enhanced their MHC class I antigen-presenting program. minP1 also synergized with PD-L1 blockade in augmenting intratumoral Tstem/Tpex cell number. Analysis of our scRNA-seq dataset by CellPhonDB suggested potential interactions between mregDCs and Tstem/Tpex cells in tumors. Our results indicate that HMGN1 peptide (minP1) serves as an immunoadjuvant to promote effective anti-PD-L1 immunotherapy with increased Tstem/Tpex cells in tumors.

The regulatory effect of acetylation of HMGN2 and H3K27 on pyocyanin-induced autophagy in macrophages by affecting Ulk1 transcription.

Pyocyanin (PYO) is a major virulence factor secreted by Pseudomonas aeruginosa, and autophagy is a crucial homeostatic mechanism for the interaction between the pathogens and the host. It remains unknown whether PYO leads to autophagy in macrophages by regulating histone acetylation. The high mobility group nucleosomal binding domain 2 (HMGN2) has been reported to regulate the PYO‐induced autophagy and oxidative stress in the epithelial cells; however, the underlying molecular mechanism has not been fully elucidated. In this study, PYO was found to induce autophagy in macrophages, and the mechanism might be correlated with the up‐regulation of HMGN2 acetylation (HMGN2ac) and the down‐regulation of H3K27 acetylation (H3K27ac) by modulation of the activities of acetyltransferases and deacetylases. Moreover, we further demonstrated that the up‐regulated HMGN2ac enhances its recruitment to the Ulk1 promoter, while the down‐regulation of H3K27ac reduces its recruitment to the Ulk1 promoter, thereby promoting or inhibiting the transcription of Ulk1. In conclusion, HMGN2ac and H3K27ac play regulatory roles in the PYO‐induced autophagy in macrophages.

HMGN5 promotes invasion and migration of colorectal cancer through activating FGF/FGFR pathway.

To detect the expression of high-mobility group nucleosome-binding domain 5 (HMGN5) in colorectal cancer tissues, to explore the function of HMGN5 on the proliferation and metastasis of colorectal cancer cells, and to further study the molecular mechanism of HMGN5 in the malignant progression of colorectal cancer (CRC). The cancer tissues and para-carcinoma tissues were harvested from 40 patients with CRC. The expression of HMGN5 was detected via quantitative real-time polymerase chain reaction (qRT-PCR), and the relation between HMGN5 and clinical indexes of CRC patients was further analyzed. The CRC HT29 and HCT116 cell lines with high expression levels of HMGN5 were selected, and the HMGN5 knockdown model was established. The functions of HMGN5 on CRC cells were stated by cell counting kit-8 (CCK-8) assay and transwell migration assay. Then, the association between HMGN5 and fibroblast growth factor 12 (FGF12) was further explored via Dual-Luciferase reporter assay and reverse assay. The qRT-PCR showed that HMGN5 expression was significantly rising in cancer tissues compared to the control group. The incidence rate of lymph node metastasis and distant metastasis was higher in higher expression HMGN5 group than the lower expression HMGN5 group. The results of cell function experiments revealed that silence of HMGN5 could suppress the proliferation and migration of HT29 and HCT116. In addition, it was found using qRT-PCR that knockdown of HMGN5 could significantly down-regulate the expressions of FGF12, FGFR, PI3K and AKT in HT29 and HCT116 cells. The targeted binding relation between HMGN5 and FGF12 was also indicated by the dual-luciferase reporter assay. The consequence of qRT-PCR manifested that FGF12 expression markedly rose in CRC tissues, which had a positive correlation with HMGN5. Moreover, reverse assay indicated that the inhibitory effect of HMGN5 knockdown on the malignant progression of CRC could be reversed by recombinant FGF12, indicating once again that there is a mutual regulatory effect between HMGN5 and FGF12. HMGN5 can increase the proliferative and migrative capacity of CRC cells via targeted binding to FGF12. In addition, clinical data analyses demonstrate that HMGN5 is intimately related to the incidence rate of lymph node metastasis and distant metastasis in patients with CRC.

Multi-Omics Analysis to Characterize Cigarette Smoke Induced Molecular Alterations in Esophageal Cells.

Though smoking remains one of the established risk factors of esophageal squamous cell carcinoma, there is limited data on molecular alterations associated with cigarette smoke exposure in esophageal cells. To investigate molecular alterations associated with chronic exposure to cigarette smoke, non-neoplastic human esophageal epithelial cells were treated with cigarette smoke condensate (CSC) for up to 8 months. Chronic treatment with CSC increased cell proliferation and invasive ability of non-neoplastic esophageal cells. Whole exome sequence analysis of CSC treated cells revealed several mutations and copy number variations. This included loss of high mobility group nucleosomal binding domain 2 (HMGN2) and a missense variant in mediator complex subunit 1 (MED1). Both these genes play an important role in DNA repair. Global proteomic and phosphoproteomic profiling of CSC treated cells lead to the identification of 38 differentially expressed and 171 differentially phosphorylated proteins. Bioinformatics analysis of differentially expressed proteins and phosphoproteins revealed that most of these proteins are associated with DNA damage response pathway. Proteomics data revealed decreased expression of HMGN2 and hypophosphorylation of MED1. Exogenous expression of HMGN2 and MED1 lead to decreased proliferative and invasive ability of smoke exposed cells. Immunohistochemical labeling of HMGN2 in primary ESCC tumor tissue sections (from smokers) showed no detectable expression while strong to moderate staining of HMGN2 was observed in normal esophageal tissues. Our data suggests that cigarette smoke perturbs expression of proteins associated with DNA damage response pathways which might play a vital role in development of ESCC.

High mobility group nucleosomal binding 2 reduces integrin α5/β1‐mediated adhesion of Klebsiella pneumoniae on human pulmonary epithelial cells via nuclear factor I

It has been reported that high mobility group nucleosomal binding domain 2 (HMGN2) is a nucleus-related protein that regulates gene transcription and plays a critical role in bacterial clearance. An elevated level of HMGN2 reduced integrin α5/β1 expression of human pulmonary epithelial A549 cells was demonstrated during Klebsiella pneumoniae infection, thus weakening bacterial adhesion and invasion. However, the mechanism by which HMGN2 regulates integrin expression remains unclear. This study found that a transcription factor-nuclear factor I (NFI), which serves as the potential target of HMGN2 regulated integrin expression. The results showed that HMGN2 was able to promote NFIA and NFIB expression by increasing H3K27 acetylation of NFIA/B promoter regions. The integrin α5/β1 expression was significantly enhanced by knockdown of NFIA/B via a siRNA approach. Meanwhile, NFIA/B silence could also compromise the inhibition effect of HMGN2 on the integrin α5/β1 expression. Mechanistically, it was demonstrated that HMGN2 facilitated the recruitment of NFI on the promoter regions of integrin α5/β1 according to the chromatin immunoprecipitation assay. In addition, it was further demonstrated that the knockdown of NFIA/B induced more adhesion of Klebsiella pneumoniae on pulmonary epithelial A549 cells, which could be reversed by the application of an integrin inhibitor RGD. The results revealed a regulatory role of HMGN2 on the transcription level of integrin α5/β1, indicating a potential treatment strategy against Klebsiella pneumoniae-induced infectious lung diseases.

Transcriptomic analysis of peripheral blood mononuclear cells in head and neck squamous cell carcinoma patients.

To investigate the gene expression profile of peripheral blood mononuclear cells (PBMCs) from head and neck squamous cell carcinoma (HNSCC), including oral cancer (OC) and oropharyngeal cancer (OPC) patients, and compare them with healthy controls (HC). Transcriptomic analysis of PBMCs was performed by RNA-sequencing. The upregulated candidate genes were selected for validation by quantitative real-time polymerase chain reaction (qPCR). In addition, related plasma protein levels were determined by enzyme-linked immunosorbent assay (ELISA). Three significantly upregulated genes, including high mobility group nucleosomal binding domain 2 (HMGN2), folate receptor gamma (FOLR3), and amphiregulin (AREG), were selected. In the first cohort, the results showed that only HMGN2 expression was significantly increased in OC patients. In the larger sample size, the overall results demonstrated that HMGN2 expression had a tendency to increase in both OC and OPC patients compared with HC. Interestingly, the plasma HMGN2 (HMG-17) protein level exhibited the same trend as that observed at the transcriptional level. HMGN2 expression and plasma HMG-17 (HMGN2 protein) were increased in both cancer patients compared with HC. This gene may be important for further functional studies in the PBMCs of HNSCC patients.

HMGN5 promotes IL-6-induced epithelial-mesenchymal transition of bladder cancer by interacting with Hsp27.

Bladder cancer (BC) is one of the most common cancers worldwide, with a high rate of recurrence and poor outcomes. High-mobility group nucleosome-binding domain 5 (HMGN5) is overexpressed in many cancers and could cause carcinogenesis in BC. By protein-protein-interaction (PPI) analysis, we found that heat shock protein 27 (Hsp27), also a crucial functional factor in BC carcinogenesis, is significantly related to HMGN5. Hsp27 is required for IL-6-mediated EMT via STAT3/Twist signaling in prostate cancer. Here, we hypothesize that HMGN5 may interact with Hsp27 to affect IL-6-induced EMT and invasion in BC via STAT3 signaling. In the present study, we found that HMGN5 and Hsp27 are highly expressed in BC tissues and positively correlated with each other. HMGN5 interacts with Hsp27 in vitro, to modulate the cell invasion and EMT in BC. Moreover, HMGN5 could modulate IL-6-Hsp27-induced EMT and invasion in BC cells by regulating STAT3 phosphorylation and STAT3 targeting of the Twist promoter. HMGN5 interacts with Hsp27 to promote tumor growth in a human BC xenograft model in nude mice. In summary, HMGN5 interacts with Hsp27 to promote IL-6-induced EMT, therefore promoting invasion in BC and contributing to the progression of BC.

High-mobility group nucleosomal binding domain 2 protects against microcephaly by maintaining global chromatin accessibility during corticogenesis

The surface area of the human cerebral cortex undergoes dramatic expansion during late fetal development, leading to cortical folding, an evolutionary feature not present in rodents. Microcephaly is a neurodevelopmental disorder defined by an abnormally small brain, and many gene mutations have been found to be associated with primary microcephaly. However, mouse models generated by ablating primary microcephaly-associated genes often fail to recapitulate the severe loss of cortical surface area observed in individuals with this pathology. Here, we show that a mouse model with deficient expression of high-mobility group nucleosomal binding domain 2 (HMGN2) manifests microcephaly with reduced cortical surface area and almost normal radial corticogenesis, with a pattern of incomplete penetrance. We revealed that altered cleavage plane and mitotic delay of ventricular radial glia may explain the rising ratio of intermediate progenitor cells to radial glia and the displacement of neural progenitor cells in microcephalic mutant mice. These led to decreased self-renewal of the radial glia and reduction in lateral expansion. Furthermore, we found that HMGN2 protected corticogenesis by maintaining global chromatin accessibility mainly at promoter regions, thereby ensuring the correct regulation of the transcriptome. Our findings underscore the importance of the regulation of chromatin structure in cortical development and highlight a mouse model with critical insights into the etiology of microcephaly.

MicroRNA-183-3p Inhibits Progression of Human Prostate Cancer by Downregulating High-Mobility Group Nucleosome Binding Domain 5.

microRNAs are a class of noncoding RNAs that play important roles in cancer progression. microRNA-183-3p (miR-183-3p) is a novel microRNA that is dysregulated in many kinds of cancers. Our previous studies found high expression and oncologic role of high-mobility group nucleosome binding domain 5 (HMGN5) in prostate cancer. In this study, we found that miR-183-3p was downregulated in prostate cancer cells and primary tissues compared with normal controls. In addition, miR-183-3p expression was negatively correlated with HMGN5 expression. On the basis of bioinformatics predication and quantitative polymerase chain reaction and Western blot verification, it is demonstrated that miR-183-3p regulated HMGN5 expression. Luciferase reporter assay confirmed that miR-183-3p directly targeted the 3'-untranslated region of HMGN5. Interestingly, cell proliferation and migration inhibition and apoptosis induction were also observed in miR-183-3p transfected human prostate cancer VCap and C4-2 cells. Moreover, overexpression of HMGN5 significantly reversed the inhibitory effect on cell proliferation and migration and promoted effect on cell apoptosis by miR-183-3p. Our data suggest that dysfunction of miR-183-3p-HMGN5 axis plays an oncogenic role and can be a therapeutic target for prostate cancer.

HMGN5 promotes proliferation and invasion via the activation of Wnt/β-catenin signaling pathway in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive carcinoma with a poor prognosis. A recent study has demonstrated that high mobility group nucleosome binding domain 5 (HMGN5) was involved in tumorigenesis and progression of multiple types of human cancers. However, the role of HMGN5 in PDAC is unknown. The objective of the present study was to analyze the function and novel mechanism of HMGN5 involved in PDAC cell progression. It was firstly revealed that the expression of HMGN5 was significantly upregulated in PDAC cell lines and tissues, when compared with that in normal pancreatic duct epithelial cells and adjacent normal pancreatic tissues. In vitro assay revealed that HMGN5 silencing impaired PDAC cell viability, proliferation, migration and invasion. Similarly, tumor growth rate was also decreased in vivo following HMGN5 silencing. Furthermore, it was demonstrated that HMGN5 silencing significantly inhibited epithelial-mesenchymal transition in vitro. Notably, HMGN5-medicated Wnt/β-catenin signaling pathway activation was observed to be one of the critical signal transduction pathways that associates HMGN5 with EMT activation. Collectively, the results indicated the important role of HMGN5 in PDAC cell proliferation and metastasis, and provide a promising target against the transcriptional program of PDAC.

HMGN5 (High Mobility Group Nucleosome binding domain 5)

HMGN5 (High Mobility Group Nucleosome binding domain 5)

HMGN2: An Antitumor Effector Molecule of γδT Cells.

γδT cells function in the regulation of T-cell activation in cancer and have been identified as a novel target for cancer immunotherapy. Activated γδT cells release a series of cytotoxic molecules-including granulysin, perforin, Fas/Fas ligand (Fas-L), and granzymes A and B-to kill target cells. Our previous research has shown that high mobility group nucleosomal-binding domain 2 (HMGN2), which is expressed at a high level in activated CD8T cells, is an antitumor effector molecule of CD8T cells. In the present study, we examined the expression and antitumor effects of HMGN2 in γδT cells. Peripheral blood mononuclear cells (PBMCs) were isolated from healthy donors with a PBMC separation column. PMBCs were stimulated with isopentenyl pyrophosphate (IPP) and interleukin-2 (IL-2) for 10 days for activation and expansion. Activated γδT cells were isolated from IPP-pretreated PBMCs with a Moflo XDP flow cytometry sorter. The expression of HMGN2 in γδT cells was detected by flow cytometry and enzyme-linked immunosorbent assay. The cytotoxic effects of γδT cells and HMGN2 were analyzed by carboxyfluorescein succinimidyl ester labeling. IPP combined with IL-2 induced significant activation and expansion of γδT cells in vitro. HMGN2 was constitutively expressed in γδT cells. IPP-activated γδT cells expressed a high level of HMGN2 that could be detected intracellularly and in the supernatant. Moreover, supernatants of purified γδT cells were sufficient to kill tumor cells and could be blocked with anti-human HMGN2 antibody. This study suggests that HMGN2 is an antitumor effector molecule of γδT cells.

MiR-488 inhibits cell growth and metastasis in renal cell carcinoma by targeting HMGN5.

PurposemicroRNAs are thought to play crucial roles in tumorigenesis. Dysregulation of miR-488 has been implicated to be involved in several cancer progressions. However, the biological functions of miR-488 in renal cell carcinoma (RCC) remain unclear. This study aimed to explore the molecular mechanism underlying the role of miR-488 in RCC development.Materials and methodsThe expression levels of miR-488 were detected in 38 paired RCC tumor samples and cell lines by quantitative real-time polymerase chain reaction method. miR-488 was upregulated by mimics transfection in RCC cell lines. MTT, colony formation, transwell assay, flow cytometry assay, and a xenograft model were performed to determine cell proliferation, invasion, migration, epithelial-to-mesenchymal transition, and apoptosis in vitro and in vivo. Moreover, the potential target of miR-488 was verified by dual-luciferase reporter assay, quantitative real-time polymerase chain reaction, and Western blot. The correlation between miR-488 expression and its target gene expression was confirmed by Spearman’s correlation analysis in 38 selected RCC tissue samples.ResultsWe found that miR-488 was remarkably downregulated in human RCC samples and cell lines compared with paired normal tissues and cell lines. Functional investigations revealed that overexpression of miR-488 significantly suppressed cell proliferation, invasion, and migration, and promoted cell apoptosis in RCC cells. Nucleosome binding protein 1 (high-mobility group nucleosome binding domain 5 [HMGN5]) was identified as a direct target of miR-488, and an inverse relationship was found between miR-488 expression and HMGN5 mRNA levels in RCC specimens. Rescue experiments suggested that restoration of HMGN5 partially abolished miR-488-mediated cell proliferation and invasion inhibition in RCC cells through regulating phosphatidylinositol 3-kinase/protein kinase B/the mammalian target of rapamycin and epithelial-to-mesenchymal transition signaling pathways.ConclusionThese data indicated that miR-488 acted as a tumor suppressor in RCC proliferation and invasion by targeting HMGN5, which might provide potential therapeutic biomarker for RCC patients.

Increased expression of high-mobility group nucleosomal-binding domain 2 protein in various tumor cell lines.

High mobility group nucleosomal-binding domain 2 (HMGN2) is an abundant non-histone nuclear protein of vertebrates and invertebrates. The aim of the present study was to characterize the endogenous expression of HMGN2 in various types of tumor cell. Western blotting was performed to analyze HMGN2 expression in the following tumor cell lines: H1975, HSC-4, MDA-MB-468, MDA-MB-231, SCC-25 and THP-1. Periodontal ligament cells (PDLCs) were included as a noncancerous control. HMGN2 was detected in human oral squamous cell carcinoma tissues by immunohistochemical analysis. The results demonstrated that the expression of HMGN2 was increased in the majority of tumor cell lines, particularly MDA-MB-468 and THP-1 cells, compared with PDLCs. The expression of HMGN2 in oral squamous cell carcinoma tissue was significantly increased compared with the expression in normal tissue. Furthermore, the expression of HMGN2 in metastatic oral squamous cell carcinoma tissues was increased compared with that in its non-metastatic counterpart. These results indicated that HMGN2 may serve an important function in the growth and metastasis of tumor cells.

Knockdown of HMGN5 increases the chemosensitivity of human urothelial bladder cancer cells to cisplatin by targeting PI3K/Akt signaling.

High-mobility group nucleosome-binding domain 5 (HMGN5) is the latest member of the HMGN family of proteins. Numerous studies have confirmed the carcinogenic role of HMGN5 in cancer, but its function in the regulation of chemosensitivity is largely unknown and controversial. A previous study by the authors of the present study demonstrated that HMGN5 contributes to the progression of urothelial bladder cancer (UBC) through regulating the expression of E-cadherin and vascular endothelial growth factor (VEGF)-C, which are associated with the sensitivity of tumor cells to cisplatin. Therefore, the present study aimed to elucidate the mechanisms underlying the regulation of HMGN5 and investigate the involvement of HMGN5 in cisplatin treatment. The results of the present study revealed that HMGN5 is able to positively regulate the expression of phosphorylated (p-)Akt in UBC cells. In addition, HMGN5 expression was negatively associated with the response of UBC cells to cisplatin. The findings indicated that HMGN5 may be a potential therapeutic target of cisplatin treatment, since cisplatin treatment reduced HMGN5 expression in a dose-dependent manner. It was also confirmed that the knockdown of HMGN5 decreased the viability, colony formation and invasion of 5637 cells but increased apoptosis under cisplatin treatment. The changes caused by HMGN5 knockdown in 5637 cells were able to be reversed by treatment with insulin-like growth factor-1 (IGF-1), which is a phosphoinositide 3-kinase (PI3K)/Akt signaling activator. Additionally, with the decreased expression of HMGN5, the expression of p-Akt, slug, E-cadherin and VEGF-C was subsequently inhibited. By contrast, the expression of cytochrome c, cleaved-caspase-3 and cleaved-poly ADP ribose polymerase was increased following HMGN5 knockdown. Consistently, these changes in protein expression were able to be reversed by IGF-1 treatment. In conclusion, findings from the in vitro experiments indicate that HMGN5 may a target of cisplatin treatment and that the inhibition of HMGN5 increases the chemosensitivity of UBC cells by inhibiting PI3K/Akt signaling.

Silencing HMGN5 suppresses cell growth and promotes chemosensitivity in esophageal squamous cell carcinoma.

Previous study has demonstrated that high mobility group nucleosome-binding domain 5 (HMGN5) is involved in tumorigenesis and the development of multidrug resistance in several human cancers. However, the role of HMGN5 in esophageal squamous cell carcinoma (ESCC) remains unclear. Here, we showed that HMGN5 was significantly upregulated in ESCC cells. Knockdown of HMGN5 significantly inhibited cell growth and induced cell apoptosis of ESCC cells. Moreover, knockdown of HMGN5 increased the sensitivity of ESCC cells towards cisplatin. By contrast, overexpression of HMGN5 showed the opposite effects. Further experiments demonstrated that HMGN5 regulated the expression of multidrug resistance 1, cyclin B1, and Bcl-2. Overall, our results reveal that HMGN5 promotes tumor progression of ESCC and is also an important regulator of chemoresistance. Our study suggests that inhibition of HMGN5 may be a potential strategy for improving effectiveness of ESCC treatment.

MicroRNA-409-3p Represses Glioma Cell Invasion and Proliferation by Targeting High-Mobility Group Nucleosome-Binding Domain 5

Emerging evidence has suggested that aberrantly expressed microRNAs (miRNAs) are associated with glioma development and progression. The aberrant expression of miR-409-3p has been reported in several human cancers. However, little is known about the function of miR-409-3p in gliomas. The aim of this study was to investigate the specific role and molecular mechanism of miR-409-3p in gliomas. In the present study, we found that miR-409-3p was downregulated in glioma tissue and cell lines. Overexpression of miR-409-3p inhibited glioma cell invasion and proliferation, whereas suppression of miR-409-3p promoted glioma cell invasion and proliferation. High-mobility group nucleosome-binding domain 5 (HMGN5), a well-known oncogene in gliomas, was identified as a functional target of miR-409-3p using bioinformatics, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction, and Western blot analysis. Furthermore, miR-409-3p was found to regulate the expression of matrix metalloproteinase 2 and cyclin D1. Restoration of HMGN5 expression significantly reversed the inhibitory effects of miR-409-3p overexpression on glioma cell invasion and proliferation. Taken together, our results suggest that miR-409-3p inhibits glioma cell invasion and proliferation by targeting HMGN5, representing a potential therapeutic target for glioma.

Antibacterial mechanism of high-mobility group nucleosomal-binding domain 2 on the Gram-negative bacteria Escherichia coli.

To investigate the antibacterial mechanism of high-mobility group nucleosomal-binding domain 2 (HMGN2) on Escherichia coli K12, focusing on the antibacterial and antibiofilm formation effects. Its chemotactic activity on human neutrophils was also investigated. Human tissue-derived HMGN2 (tHMGN2) was extracted from fresh uterus fiber cystadenoma and purified by HP1100 reversed-phase high-performance liquid chromatography (RP-HPLC). Recombinant human HMGN2 (rHMGN2) was generated in E. coli DE3 carrying PET-32a-c(+)-HMGN2. Antibacterial activity of HMGN2 was determined using an agarose diffusion assay and minimum inhibitory concentration (MIC) of HMGN2 was determined by the microdilution broth method. Bacterial membrane permeability assay and DNA binding assay were performed. The antibiofilm effect of HMGN2 was investigated using a crystal violet assay and electron microscopy scanning. The activating effect and chemotactic activity of HMGN2 on neutrophils were determined using a nitroblue tetrazolium (NBT) reduction assay and Transwell chamber cell migration assay, respectively. HMGN2 showed a relatively high potency against Gram-negative bacteria E. coli and the MIC of HMGN2 was 16.25 μg/ml. Elevated bacterial membrane permeability was observed in HMGN2-treated E. coli K12. HMGN2 could also bind the bacterial plasmid and genomic DNA in a dose-dependent manner. The antibiofilm effect of HMGN2 on E. coli K12 was confirmed by crystal violet staining and scanning electron microscopy. However, the activating effects and chemotactic effects of HMGN2 on human neutrophils were not observed. As an antimicrobial peptide (AMP), HMGN2 possessed a good capacity for antibacterial and antibiofilm activities on E. coli K12. This capacity might be associated with disruption of the bacterial membrane and combination of DNA, which might affect the growth and viability of E. coli.