High Mobility Group A1 Expression Research Articles

HMGA2 regulates GPX4 expression and ferroptosis in prostate cancer cells

Prostate cancer (PCa) remains a significant global health burden and an increase in oxidative stress is associated with cancer progression. High Mobility Group A2 (HMGA2), a chromatin architectural protein, increases oxidative stress and promotes sensitivity to ferroptosis inducers, however, the mechanism is unknown. We investigated the role of HMGA2 in GPX4 regulation and the impact on cellular responses to oxidative stress and ferroptosis sensitivity. We conducted UALCAN database analysis, western blot analysis, and lipid peroxidation assays to determine the relationship between HMGA2 and GPX4 and the levels of lipid reactive oxygen species in a panel of PCa cell lines, including an enzalutamide-resistant cancer cell line (C4–2B MDVR). Our results show an inverse relationship between HMGA2 and GPX4 expression with high HMGA2 and low GPX4 expression associated with higher Gleason score and lower survival probability in prostate adenocarcinoma (PRAD) patients, while low/moderate HMGA2 expression is positively associated with increased GPX4 expression and higher survival probability. Cell lines showed a moderately negative but not statistically significant correlation between HMGA2 and GPX4 expression, however, PC3 and DU145 PCa cells display higher lipid peroxides concomitant with higher endogenous levels of HMGA2 and low GPX4. Overexpression of wild-type HMGA2 in LNCaP and 22Rv1 cells leads to higher HMGA2 expression compared to Neo control and is associated with higher SLC7A11 and GPX4 expression, while interestingly truncated HMGA2 overexpression in LNCaP and 22Rv1 cells coincides with higher HMGA2 and reduced GPX4 expression, leading to increased lipid peroxides and susceptibility to ferroptosis. Overexpression of wild-type and truncated HMGA2 in 22Rv1 cells increases SLC7A11 mRNA yet differing GPX4 protein expression suggests posttranslational regulation of GPX4. Moreover, enzalutamide-resistant C4–2B MDVR cells display higher HMGA2 levels compared to C4–2B cells, as well as sensitivity to RSL3 ferroptosis inducer, which is partially reversed by ferroptosis inhibitor, ferrostatin-1. Interestingly, GPX4 expression is higher in C4–2B MDVR cells compared to C4–2B, and HMGA2 knockdown further increases its expression but does not significantly alter its susceptibility to ferroptosis. In conclusion, our study shows that HMGA2 regulation of GPX4 expression is complex and truncated HMGA2 downregulates GPX4 and increases lipid peroxides. Moreover, HMGA2-expressing cells including enzalutamide-resistant cells are susceptible to RSL-3-induced ferroptosis. Thus, ferroptosis sensitivity offers promising insights for the development of targeted therapeutic interventions for aggressive PCa.

HMGA1 Regulates IRS2 to Promote Inflammatory Responses and Oxidative Stress Injury in MPP+-Induced cells.

Parkinson's disease (PD) is a prevalent neurodegenerative disorder for which novel treatment approaches are continuously sought. This study investigates the role of high-mobility group A1 (HMGA1) in modulating inflammatory responses and oxidative stress injury in PD. We utilized the murine dopaminergic neuronal cell line MN9D, treating cells with 1-methyl-4-phenylpyridinium ion (MPP+) to mimic PD conditions. The expression levels of HMGA1 and insulin receptor substrate 2 (IRS2) were measured using quantitative polymerase chain reaction and Western blot assay. Cell damage was assessed with cell counting kit-8 and lactate dehydrogenase assays. Inflammatory response and oxidative stress were evaluated by quantifying interleukin (IL)-1β, IL-6, tumor necrosis factor-α, reactive oxygen species, superoxide dismutase, and malondialdehyde (MDA) levels using enzyme-linked immunosorbent assay and commercial kits. The binding interaction between HMGA1 and IRS2 was analyzed using chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays. Our findings revealed that MPP+ treatment increased the expression of HMGA1 and IRS2. Downregulation of HMGA1 enhanced cell viability, reduced inflammation, and mitigated oxidative stress in MPP+-induced cells. Further investigation demonstrated that HMGA1 bounded to the IRS2 promoter, enhancing IRS2 expression. Overexpression of IRS2 counteracted the protective effects of HMGA1 downregulation. In conclusion, HMGA1 exacerbates MPP+-induced cell damage by activating IRS2 transcription, which in turn heightens inflammation and oxidative stress. These findings suggest that targeting HMGA1 could be a potential therapeutic strategy for PD.

HMGA1 is a Prognostic Biomarker and Correlated with Glycolysis in Lung Adenocarcinoma.

Purpose: Lung cancer is one of the leading causes with high morbidity and mortality. High mobility group A1 (HMGA1) protein participates in the process of tumorigenesis. This study seeks to explore the specific role of HMGA1 in prognostic value based on The Cancer Genome Atlas (TCGA) database of Lung adenocarcinoma (LUAD) and glycolysis progression in LUAD cells. Patients and Methods: In this research, we compared HMGA1 mRNA expression between tumor tissues and normal samples and evaluated the correlations with clinical characteristics in LUAD patients based on the data of TCGA database. The survival outcome with overall survival (OS), disease-specific survival (DSS) and clinicopathologic characteristics associated were performed using the Kaplan-Meier method and Cox regression. In addition, gene-set enrichment analysis (GSEA) was carried out to explore the biological pathways that related to HMGA1. Cell experiments including cell proliferation assay and glycolysis proteins were performed with A549 and H1299 cells. Results: Our results revealed that HMGA1 mRNA expression was higher in LUAD tissues than in normal tissues. Increased HMGA1 expression in LUAD was associated with Gender (p<0.01), Pathologic stage I&II vs stage III&IV (p<0.001), T1&T2 vs T3&T4 stage (p<0.05), N0 vs N2 stage (p<0.01). Furthermore, multivariate analysis revealed that HMGA1 was an independent risk factor of OS and DSS for LUAD patients (p<0.05). HMGA1 were positively correlated with glycolysis gluconeogenesis pathway and glycolysis markers (HK2, GLUT1, PKM2, LDHA) based on GSEA and Gene Expression Profiling Interactive Analysis (GEPIA) database. At the cellular level, the results of qRT-PCR and western blot assays showed that si-HMGA1 markedly decreased the expression of glycolysis markers. HMGA1 promoted cell glycolysis progression via PI3K/AKT pathway transfected with HMGA1-plasmid and the treatment with 20 μM LY294002. Relevant animal experiments were also synchronously validated and si-HMGA1 groups down-regulated xenograft growth including the weights and size in tumor xenografts. Conclusions: In conclusion, our results suggested that HMGA1 was significantly correlated with poor survival for LUAD tissues and involved in the process of glycolysis in LUAD cells.

LINC02532 by Mediating miR-541-3p/HMGA1 Axis Exerts a Tumor Promoter in Breast cancer.

The newly discovered LINC02532 is abnormally expressed in a variety of cancers and promotes cancer progression. The research proposed to discover the biological and molecular mechanisms of LINC02532 in breast cancer (BCa). In the resected BCa tissue samples and adjacent normal tissues, LINC02532, miR-541-3p, and High Mobility Group A1 (HMGA1) levels were determined. Cell function experiments were carried out on the premise of cell transfection with relevant plasmids. Based on that, the influence of LINC02532, miR-541-3p, and HMGA1 on MCF-7 cell activities (proliferation, migration, invasion, cell cycle, and apoptosis) was determined, as well as on EMT. Additionally, animal experiments were allowed to support cell experimental conclusions on LINC02532. Finally, the mechanistic network of LINC02532, miR-541-3p, and HMGA1 was identified. It was BCa tissues highly expressing LINC02532 and HMGA1, while lowly expressing miR-541-3p. Functionally, LINC02532 depletion repressed the activities and EMT process of MCF-7 cells. Silencing LINC02532 delayed tumor growth in mice. In terms of mechanism, LINC02532 mainly existed in the cytoplasm and could mediate HMGA1 expression by absorbing miR-541-3p. The findings offer new insights into the molecular mechanisms of LINC02532 in BCa and, more importantly, new strategies for the clinical treatment of BCa.

High Mobility Group A1 Chromatin Regulators Drive Regenerative Capacity during Stress Hematopoiesis through Modulation of TNF-α and Aging Transcriptional Networks

Introduction: Chromatin structure and epigenetic modifications are key determinants of regenerative function and cell fate decisions, although mechanisms governing these properties in hematopoiesis are only beginning to emerge. The High Mobility Group A1 ( HMGA1) chromatin regulator gene is induced by growth factors and highly expressed during embryogenesis and in hematopoietic stem cells (HSCs), but silenced in differentiated tissues ( Cancer Res 2018,78:1890). In leukemia and solid tumors, HMGA1 is re-expressed where it activates enhancers that induce stem cell transcriptional networks, leading to aberrant proliferation and differentiation ( Blood 2022,139:2797; JCI 2023 133:e151601). HMGA1 also drives self-renewal by amplifying Wnt networks in intestinal stem cells ( Nature Comm 2017,8:15008). However, its role in normal hematopoiesis is unknown. We therefore sought to: 1) Define HMGA1 function in HSC, and, 2) Test the hypothesis that modulating HMGA1 epigenetic networks enhances regenerative function. Methods: First, we compared HMGA1 expression across hematopoietic stem and progenitor cells (HSPC) and differentiated progeny in humans and mice. Next, we generated mice with global Hmga1 knock-out ( Hmga1-KO) or Hmga1 deficiency confined to HSC (vav- Hmga1-KO) to assess HSPC function in clonogenic assays, competitive bone marrow transplantation (cBMT), and following irradiation. To elucidate underlying mechanisms, we performed single cell RNA sequencing (scRNAseq) of bone marrow (BM)-derived Lin -, Sca +, c-kit + (LSK) cells followed by pathway analysis. To assess HMGA1 function in human CD34 + cells, we used CRISPR to inactivate HMGA1. Results: HMGA1 is expressed in HSC, multipotent progenitors (MPP), and megakaryocyte-erythroid progenitors (MEP), with decreasing levels after differentiation, suggesting that HMGA1 functions in stem and progenitors. However, steady state hematopoiesis is unperturbed in both Hmga1-KO and vav- Hmga1-KO mice up to 18 months. By contrast, HSPC lacking Hmga1 show decreases in total colony forming units (CFU), but only after serial replating, suggesting that Hmga1 deficiency impairs long-term HSC (LT-HSC) regenerative function. Accordingly, in cBMT assays, Hmga1-KO HSC are outcompeted by HSC with both Hmga1 alleles, with most pronounced effects after serial transplantation. Serial cBMT from young donors (6 weeks) show decreases in LT-HSC, short-term HSC (ST-HSC), and progenitors from Hmga1 KO HSPC compared to control HSPC. Results were similar with older donors (4 months, 18 months). Following irradiation, vav- Hmga1-KO mice have impaired platelet recovery, although the frequency of HSPC in bone marrow were similar to controls. HSPC function in clonogenic assays is also impaired after irradiation, as evidenced by decreases in total CFU, GM-CFU and megakaryocyte (Mk)-CFU. To determine how HMGA1 modulates cell state, we compared scRNAseq in BM-derived LSK cells from adult mice (4 months old) with intact Hmga1 to those with Hmga1-KO. The transcriptomes in HSPC lacking Hmga1 were distinct from those with both Hmga1 alleles intact. The Hmga1 KO HSPC show a decrease in quiescent HSC (marked by high Procr expression), with a relative expansion in more proliferative HSC and early progenitors. In human CD34 + cells, CRISPR-mediated HMGA1 inactivation decreases total CFU, GM-CFU, and Mk-CFU. To elucidate underlying mechanisms, we applied gene set enrichment analyses to scRNAseq results which revealed that Hmga1 activates TNF-a signaling via NF-κB, a pathway that maintains HSC survival and regeneration following inflammatory stress. Hmga1 also represses aging-related transcriptional networks. Further, TNFa partially rescues HSC with Hmga1 deficiency in serial clonogenicity assays. Conclusions: HMGA1 deficiency impairs HSC regenerative capacity under conditions of stress hematopoiesis by depleting quiescent HSC. Mechanistically, HMGA1 induces transcriptional networks involved in survival signals, including TNFa -NF-κB networks, while repressing transcriptional networks activated with aging. Further, TNF-apartially rescues regenerative capacity in clonogenicity assays. Our findings highlight HMGA1 as a critical factor in stress hematopoiesis and suggest that modifying its function could enhance regenerative capacity and repress aging pathways following BMT or irradiation.

Establishment and characterization of a novel cancer stem-like cell of cholangiocarcinoma.

Cholangiocarcinoma (CCA) is an aggressive malignant tumor of bile duct epithelia. Recent evidence suggests the impact of cancer stem cells (CSC) on the therapeutic resistance of CCA; however, the knowledge of CSC in CCA is limited due to the lack of a CSC model. In this study, we successfully established a stable sphere-forming CCA stem-like cell, KKU-055-CSC, from the original CCA cell line, KKU-055. The KKU-055-CSC exhibits CSC characteristics, including: (1) the ability to grow stably and withstand continuous passage for a long period of culture in the stem cell medium, (2) high expression of stem cell markers, (3) low responsiveness to standard chemotherapy drugs, (4) multilineage differentiation, and (5) faster and constant expansive tumor formation in xenograft mouse models. To identify the CCA-CSC-associated pathway, we have undertaken a global proteomics and functional cluster/network analysis. Proteomics identified the 5925 proteins in total, and the significantly upregulated proteins in CSC compared with FCS-induced differentiated CSC and its parental cells were extracted. Network analysis revealed that high mobility group A1 (HMGA1) and Aurora A signaling through the signal transducer and activator of transcription 3 pathways were enriched in KKU-055-CSC. Knockdown of HMGA1 in KKU-055-CSC suppressed the expression of stem cell markers, induced the differentiation followed by cell proliferation, and enhanced sensitivity to chemotherapy drugs including Aurora A inhibitors. In silico analysis indicated that the expression of HMGA1 was correlated with Aurora A expressions and poor survival of CCA patients. In conclusion, we have established a unique CCA stem-like cell model and identified the HMGA1-Aurora A signaling as an important pathway for CSC-CCA.

Nuclear High Mobility Group A2 (HMGA2) Interactome Revealed by Biotin Proximity Labeling.

The non-histone chromatin binding protein High Mobility Group AT-hook protein 2 (HMGA2) has important functions in chromatin remodeling, and genome maintenance and protection. Expression of HMGA2 is highest in embryonic stem cells, declines during cell differentiation and cell aging, but it is re-expressed in some cancers, where high HMGA2 expression frequently coincides with a poor prognosis. The nuclear functions of HMGA2 cannot be explained by binding to chromatin alone but involve complex interactions with other proteins that are incompletely understood. The present study used biotin proximity labeling, followed by proteomic analysis, to identify the nuclear interaction partners of HMGA2. We tested two different biotin ligase HMGA2 constructs (BioID2 and miniTurbo) with similar results, and identified known and new HMGA2 interaction partners, with functionalities mainly in chromatin biology. These HMGA2 biotin ligase fusion constructs offer exciting new possibilities for interactome discovery research, enabling the monitoring of nuclear HMGA2 interactomes during drug treatments.

Association between HMGA1 and immunosuppression in hepatocellular carcinoma: A comprehensive bioinformatics analysis.

The high mobility group A1 (HMGA1) gene is overexpressed in malignant tumors, and its expression level correlates with the progression and metastasis of tumors. However, the specific role of HMGA1 in hepatocellular carcinoma (HCC) and relevant influencing approaches in tumor immunity remain unclear. In this study, the expression and clinical significance of HMGA1 in HCC immunity were analyzed. The expression levels of HMGA1 mRNA and protein in HCC tissue and normal liver tissue were analyzed based on the cancer genome atlas, the gene expression omnibus and the Human Protein Atlas databases. The correlation between HMGA1 and clinicopathological factors was analyzed, and survival was estimated based on the expression of HMGA1. Gene set cancer analysis and the TISIDB database were used to identify tumor-infiltrating immune cells and immune inhibitors. Gene set enrichment analysis was performed to determine the involved signaling pathway. The HMGA1 genetic alterations were identified with the cBioPortal for Cancer Genomics. The expression of HMGA1 mRNA and protein was significantly higher in HCC tissue and negatively correlated with survival. Neutrophils, Th17 cells, several immune inhibitors, and signaling pathways were positively correlated with the expression of HMGA1. Amplification was the main type of genetic alteration in HMGA1. These findings demonstrate that HMGA1 can be a therapeutic target and a potential biomarker to predict the prognosis of patients with HCC. HMGA1 may affect the progression of HCC by suppressing the immune function of these patients.

HMGA1 Regulates the Expression of Replication-Dependent Histone Genes and Cell-Cycle in Breast Cancer Cells.

Breast cancer (BC) is the primary cause of cancer mortality in women and the triple-negative breast cancer (TNBC) is the most aggressive subtype characterized by poor differentiation and high proliferative properties. High mobility group A1 (HMGA1) is an oncogenic factor involved in the onset and progression of the neoplastic transformation in BC. Here, we unraveled that the replication-dependent-histone (RD-HIST) gene expression is enriched in BC tissues and correlates with HMGA1 expression. We explored the role of HMGA1 in modulating the RD-HIST genes expression in TNBC cells and show that MDA-MB-231 cells, depleted of HMGA1, express low levels of core histones. We show that HMGA1 participates in the activation of the HIST1H4H promoter and that it interacts with the nuclear protein of the ataxia-telangiectasia mutated locus (NPAT), the coordinator of the transcription of the RD-HIST genes. Moreover, we demonstrate that HMGA1 silencing increases the percentage of cells in G0/G1 phase both in TNBC and epirubicin resistant TNBC cells. Moreover, HMGA1 silencing causes an increase in epirubicin IC50 both in parental and epirubicin resistant cells thus suggesting that targeting HMGA1 could affect the efficacy of epirubicin treatment.

CEP55 3'-UTR promotes epithelial-mesenchymal transition and enhances tumorigenicity of bladder cancer cells by acting as a ceRNA regulating miR-497-5p.

Centrosomal protein 55 (CEP55) is implicated in the tumorigenesis of bladder cancer (BC) but the detailed molecular mechanisms are unknown. We aim to develop a potential competing endogenous RNA (ceRNA) network related with CEP55 in BC. We first extracted the expression profiles of RNAs from The Cancer Genome Atlas (TCGA) database and used bioinformatic analysis to establish ceRNAs in BC. Real-time quantity PCR (RT-qPCR) and immunohistochemical analysis were performed to measure CEP55 expression in different bladder cell lines and different grades of cancer. Bioinformatics analysis and luciferase assays were conducted to predict potential binding sites among miR-497-5p, CEP55, parathyroid hormone like hormone (PTHLH) and high mobility group A2 (HMGA2). Tumor xenograft model was used to show the effect of CEP55 3'-UTR on cisplatin therapy. Bioinformatics analysis, luciferase assays, and 5' rapid amplification of cDNA ends (5'RACE) were to explore the function of CEP55 3'-untranslated region (3'-UTR) on targeting miR-497-5p. Western blot and immunofluorescence assays were to detect the epithelial-mesenchymal transition (EMT) induction of CEP55 3'-UTR. CEP55 expression as well as the expression levels of the oncogenic proteins PTHLH and HMGA2 were upregulated in BC cells while miR-497-5p was downregulated. Low miR-497-5p expression and high CEP55 and HMGA2 expression levels were associated with more advanced tumor clinical stage and pathological grade. Overexpression of the CEP55 3'-UTR promoted the proliferation, migration, and invasion of the EJ cell line in vitro and accelerated EJ-derived tumor growth in nude mice, while inhibition of the CEP55 3'-UTR suppressed all of these oncogenic processes. In addition, CEP55 3'-UTR upregulation reduced the cisplatin sensitivity of BC cell lines and xenograft tumors. Bioinformatics analysis, luciferase assays, and 5'RACE suggested that the CEP55 3'-UTR functions as a ceRNA targeting miR-497-5p, leading to miR-497-5p downregulation and disinhibition of PTHLH and HMGA2 expression. Further, CEP55 downregulated miR-497-5p transcription by promoting NF-[Formula: see text]B signaling. In turn, CEP55 3'-UTR ultimately promotes EMT and tumorigenesis by activating P38MAPK and ERK 1/2 pathways. These results suggest that a ceRNA regulatory network involving CEP55 upregulates PTHLH and HMGA2 expression by suppressing endogenous miR-497-5p. We unveiled a novel mechanism of BC metastasis, and could become novel therapeutics targets in BC.

HMGA2 mediates Cr (VI)-induced metabolic reprogramming through binding to mitochondrial D-Loop region.

Hexavalent chromium [Cr (VI)] exists environmentally and occupationally. It has been shown to pose a carcinogenic hazard in certain occupations. This study was to investigate the role of high mobility group A2 (HMGA2) in Cr (VI)-induced metabolism reprogramming from oxidative phosphorylation (OXPHOS) to glycolysis in A549 and HELF cells. First, knockdown of HMGA2 by siHMGA2 significantly attenuated Cr (VI)-reduced expression of OXPHOS-related proteins (COX IV and ND1) and mitochondrial mass, indicating that HMGA2 was involved in Cr (VI)-reduced OXPHOS. Overexpression of HMGA2 by transfection of HMGA2-DNA plasmids reduced the expression of COX IV, ND1 and mitochondrial mass, suggesting the negative role of HMGA2 in OXPHOS. Secondly, both CCCP, the inhibitor of mitochondrial function, and the ER stress inhibitor, 4-phenylbutyric acid (4-PBA), decreased the level of HMGA2, indicating that the interaction of mitochondrial dysfunction and ER stress resulted in Cr (VI)-induced HMGA2 expression. Further study demonstrated that ER stress/HMGA2 axis mediated the metabolism rewiring from OXPHOS to aerobic glycolysis. Notably, Cr (VI) induced the accumulation of HMGA2 proteins in mitochondria and ChIP assay demonstrated that HMGA2 proteins could bind to D-loop region of mitochondrial DNA (mtDNA), which provided the proof for HMGA2-modulating OXPHOS. Taken together, our results suggested that the interaction of mitochondria and ER stress-enhanced HMGA2 played an important role in Cr (VI)-induced metabolic reprogramming from OXPHOS to glycolysis by binding directly to D-loop region of mtDNA. This work informs on the potential mode of action for Cr (VI)-induced tumors and builds on growing evidence regarding the contribution of cellular metabolic disruption contributing to carcinogenicity.

Apelin‐mediated deamidation of HMGA1 promotes tumorigenesis by enhancing SREBP1 activity and lipid synthesis

Enhanced fatty acid synthesis provides proliferation and survival advantages for tumor cells. Apelin is an adipokine, which serves as a ligand of G protein-coupled receptors that promote tumor growth in malignant cancers. Here, we confirmed that apelin increased sterol regulatory element-binding protein 1 (SREBP1) activity and induced the expression of glutamine amidotransferase for deamidating high-mobility group A 1 (HMGA1) to promote fatty acid synthesis and proliferation of lung cancer cells. This post-translational modification stabilized the HMGA1 expression and enhanced the formation of the apelin-HMGA1-SREBP1 complex to facilitate SREBP1 activity for lipid metabolism and lung cancer cell growth. We uncovered the pivotal role of apelin-mediated deamidation of HMGA1 in lipid metabolism and tumorigenesis of lung cancer cells.

LncRNA HIT000218960 enhances resistance to 5-fluorouracil by promoting HMGA2 and activating the AKT/mTOR/P70S6K pathway in gastric cancer cells.

The aim of the present study was to investigate the effect of the long noncoding RNA HIT000218960 on gastric cancer cell resistance to 5-fluorouracil (5-FU) and to explore the underlying molecular mechanism. HIT000218960 expression was measured in gastric cancer tissues and cells lines using reverse transcription-quantitative PCR and western blotting. Gastric cancer cell lines with overexpressed or repressed HIT000218960 levels were generated to study its influence on apoptosis induced by 5-FU, which was analyzed using flow cytometry analysis. Compared with those in normal gastric mucosal tissues and non-cancerous gastric mucosal epithelial cells, HIT000218960 and high mobility group A2 (HMGA2) proteins were found to be upregulated in gastric cancer tissues and cells. Additionally, a positive correlation was found between the expression of HIT000218960 and HMGA2 in gastric cancer tissues. In patients with gastric cancer, HIT000218960 expression was revealed to associate negatively with the efficacy of chemotherapy and 3-year overall survival rate. Overexpression of HIT000218960 suppressed apoptosis in SNU-5 cells, whilst HIT000218960 knockdown increased the apoptosis of NCI-N87 cells following 5-FU treatment. Downstream, HIT000218960 was demonstrated to promote HMGA2 protein expression in gastric cancer cells. In these cells, knocking down HMGA2 expression significantly increased apoptosis in addition to reducing AKT, mTOR and P70S6 kinase (P70S6K) phosphorylation after 5-FU treatment. In conclusion, HIT000218960 is overexpressed in gastric cancer tissues and cells, which is associated with the efficacy of chemotherapy. Mechanistically, this may be mediated by the upregulation HMGA2 expression and AKT/mTOR/P70S6K signaling.

High Mobility Group A 1 Expression as a Poor Prognostic Marker Associated with Tumor Invasiveness in Gastric Cancer

The prognosis of advanced gastric cancer remains poor. Overexpression of high mobility group A 1 (HMGA1) in breast cancer and neuroblastoma indicates a poor prognosis. However, the relationship between HMGA1 expression and gastric cancer development remains unclear. Treatment strategies can be developed by identifying potential markers associated with gastric cancer. We used a constructed tissue array and performed hematoxylin and eosin and immunohistochemical staining. We quantified the staining results and performed statistical analysis to evaluate the relationship between HMGA1 expression and prognosis. HMGA1 expression was related to the expression of Ki-67, caspase3, CD31, N-cadherin, fibronectin, pAkt, and pErk. In the Kaplan–Meier graph, higher HMGA1 expression levels were associated with a relatively poor survival rate (p = 0.04). High expression of HMGA1 leads to a low survival rate, which is associated with HMGA1, proliferation, apoptosis, angiogenesis, epithelial-mesenchymal transition, and tyrosine kinase.

HMGA1 positively regulates the microtubule-destabilizing protein stathmin promoting motility in TNBC cells and decreasing tumour sensitivity to paclitaxel

High Mobility Group A1 (HMGA1) is an architectural chromatin factor involved in the regulation of gene expression and a master regulator in Triple Negative Breast Cancer (TNBC). In TNBC, HMGA1 is overexpressed and coordinates a gene network that controls cellular processes involved in tumour development, progression, and metastasis formation. Here, we find that the expression of HMGA1 and of the microtubule-destabilizing protein stathmin correlates in breast cancer (BC) patients. We demonstrate that HMGA1 depletion leads to a downregulation of stathmin expression and activity on microtubules resulting in decreased TNBC cell motility. We show that this pathway is mediated by the cyclin-dependent kinase inhibitor p27kip1 (p27). Indeed, the silencing of HMGA1 expression in TNBC cells results both in an increased p27 protein stability and p27-stathmin binding. When the expression of both HMGA1 and p27 is silenced, we observe a significant rescue in cell motility. These data, obtained in cellular models, were validated in BC patients. In fact, we find that patients with high levels of both HMGA1 and stathmin and low levels of p27 have a statistically significant lower survival probability in terms of relapse-free survival (RFS) and distant metastasis-free survival (DMFS) with respect to the patient group with low HMGA1, low stathmin, and high p27 expression levels. Finally, we show in an in vivo xenograft model that depletion of HMGA1 chemo-sensitizes tumour cells to paclitaxel, a drug that is commonly used in TNBC treatments. This study unveils a new interaction among HMGA1, p27, and stathmin that is critical in BC cell migration. Moreover, our data suggest that taxol-based treatments may be more effective in reducing the tumour burden when tumour cells express low levels of HMGA1.

High Mobility Group A1 Regulates Transcription Levels of Oligodendrocyte Marker Genes in Cultured Oligodendrocyte Precursor Cells.

Oligodendrocyte precursor cells (OPCs) serve as progenitor cells of terminally differentiated oligodendrocytes. Past studies have confirmed the importance of epigenetic system in OPC differentiation to oligodendrocytes. High mobility group A1 (HMGA1) is a small non-histone nuclear protein that binds DNA and modifies the chromatin conformational state. However, it is still completely unknown about the roles of HMGA1 in the process of OPC differentiation. In this study, we prepared primary OPC cultures from the neonatal rat cortex and examined whether the loss- and gain-of-function of HMGA1 would change the mRNA levels of oligodendrocyte markers, such as Cnp, Mbp, Myrf and Plp during the process of OPC differentiation. In our system, the mRNA levels of Cnp, Mbp, Myrf and Plp increased depending on the oligodendrocyte maturation step, but the level of Hmga1 mRNA decreased. When HMGA1 was knocked down by a siRNA approach, the mRNA levels of Cnp, Mbp, Myrf and Plp were smaller in OPCs with Hmga1 siRNA compared to the ones in the control OPCs. On the contrary, when HMGA1 expression was increased by transfection of the Hmga1 plasmid, the mRNA levels of Cnp, Mbp, Myrf and Plp were slightly larger compared to the ones in the control OPCs. These data may suggest that HMGA1 participates in the process of OPC differentiation by regulating the mRNA expression level of myelin-related genes.

LncRNA TMPO antisense RNA 1 promotes the malignancy of cholangiocarcinoma cells by regulating let-7g-5p/ high-mobility group A1 axis

ABSTRACT Cholangiocarcinoma (CHOL) is often diagnosed at an advanced stage; therefore, exploring its key regulatory factors is important for earlier diagnosis and treatment. This study aimed to identify the mechanisms of long non-coding RNA (lncRNA) TMPO Antisense RNA 1 (TMPO-AS1), microRNA let-7 g-5p, and high-mobility group A1 (HMGA1) proteins in CHOL. Our results, through quantitative real-time PCR and Western blot detection, showed that TMPO-AS1 and HMGA1 were overexpressed while let-7 g-5p was underexpressed in CHOL. Cell function experiments in CHOL cells revealed that TMPO-AS1 knockdown inhibited cell proliferation, colony formation, and cell migration, but induced apoptosis. TMPO-AS1 knockdown also suppressed tumor growth in vivo. Together with luciferase assay and Western blotting, we found that TMPO-AS1 could sponge let-7 g-5p to promote HMGA1 expression. Moreover, HMGA1 overexpression attenuated the effect of TMPO-AS1 downregulation in CHOL cells. Overall, our findings identified the oncogenic effect of TMPO-AS1 on CHOL cells, which may put forward a novel methodology for CHOL diagnosis and therapy.

CircABCC1 promotes the development of glioma by sponging miR-591 and modulating high-mobility group A2.

CircABCC1 plays an oncogenic role in diverse malignancies. In this study, we investigated its involvement in glioma. The expression of circABCC1 and miR-591 was detected in glioma tissues and cell lines. Gain- and loss-of-function assays were performed to determine the biological effects of circABCC1, miR-591, and high-mobility group A2 (HMGA2) in glioma cells. The circABCC1-mediated competitive endogenous RNA (ceRNA) regulatory mechanism was explored by bioinformatics and the luciferase reporter assay combined with the biotinylated RNA pulldown assay. The effect of circABCC1 on the tumorigenicity of glioma in vivo was detected by constructing xenografts in nude mice. CircABCC1 was highly expressed, and miR-591 was downregulated in glioma tissues and cells. Suppression of circABCC1 repressed the malignant behaviors of glioma cells and tumor growth. Through the ceRNA mechanism, circABCC1 interacts with miR-591 to regulate the expression of HMGA2. CircABCC1 functions as an oncogene to promote the progression of glioma via the regulation of miR-591/HMGA2 signaling. In summary, as revealed by our study, circABCC1 promotes the expression of HMGA2 via sponging of miR-591, thus affecting glioma progression as an important onco-circRNA.

Exosomal microRNA-107 reverses chemotherapeutic drug resistance of gastric cancer cells through HMGA2/mTOR/P-gp pathway

BackgroundRNA cargo in exosomes, especially microRNAs (miRNAs), play an important role in the chemotherapy drug resistance of human cancers. However, the role and mechanism of exosomal miR-107 on multidrug resistance of gastric cancer cells was still not clear. In this study, we sought to explore whether exosomal miR-107 could reverse the resistance of gastric cancer cells to the chemotherapy drugs.MethodsWe extracted exosomes from sensitive (SGC-7901, MGC-803) and resistant (SGC-7901/5-FU) gastric cancer cells by ultracentrifugation and the isolated exosomes were identified using transmission electron microscopy (TEM) and dynamic light scattering analysis (DLS). The expression of miR-107 and high mobility group A2 (HMGA2) were detected by real-time quantitative PCR (RT-qPCR). MTT assay was used to investigate the effect of exosomes on gastric cancer cells growth in vitro. The uptake of exosomes by recipient cells were observed using a fluorescence microscope. The predicted target relationship between miR-107 and HMGA2 was verified by gauss-luciferase reporter assay. The expression of HMGA2, p-mTOR/mTOR, P-gp and other exosomal indicated marker proteins was detected by western blot.ResultsOur results indicated that the isolated exosomes were typically cup-like lipid bilayer membranes structure. SGC-7901/5-FU cells were cross-resistant to chemotherapy drug cisplatin (CDDP), and the sensitive cells-secreted exosomes drastically reversed the resistance of the resistant GC cells to the chemotherapeutic drugs, which was verified by exosomal inhibitor GW4896. Mechanistically, the reversal effect was mainly mediated by exosome-secreted miR-107 through downregulating the expression of target molecular HMGA2 and inhibiting HMGA2/mTOR/P-gp pathway, which were supported by results from luciferase reporter assay and rescue assay.ConclusionsThese findings demonstrated that exosome-transmitted miR-107 significantly enhanced the sensitivity of resistant gastric cancer cells to chemotherapeutic agents by mediating the HMGA2/mTOR/P-gp axis and exosomal miR-107 may be a novel target in gastric cancers treatment.

High Mobility Group A1 (HMGA1) Epigenetic Regulators Induce ETV5 Networks in Relapsed B-Cell Leukemia and Provide Novel Therapeutic Targets

Introduction: Despite advances in therapy for B-cell acute lymphoblastic leukemia (B-ALL), relapsed disease remains the leading cause of death in children with cancer. The gene encoding the High Mobility Group A1 (HMGA1) chromatin regulator is highly expressed in stem cells and diverse malignancies where high levels portend poor outcomes. We discovered that transgenic mice misexpressing Hmga1 in lymphoid cells develop leukemic transformation by amplifying transcriptional networks involved in stem cell function, proliferation, and inflammation (Hillion et al, Cancer Res 2008, Schuldenfrei et al, BMC Genomics 2011, Xian et al, Nature Commun 2017). In pediatric B-ALL (pB-ALL), HMGA1 is overexpressed with highest levels in blasts from early relapse (Roy et al, Leuk Lymphoma 2013). Together, these findings suggest that HMGA1 is required for leukemogenesis and drives relapse through epigenetic reprogramming. We therefore sought to: 1) test the hypothesis that HMGA1 is required for leukemogenesis and relapse in pB-ALL, and, 2) elucidate targetable mechanisms mediated by HMGA1.Methods: To elucidate the function of HMGA1 and downstream targets, we employed CRISPR/Cas9 gene inactivation and lentiviral-mediated gene silencing via delivery of short hairpin RNA (shRNA) targeting 2 sequences per gene in cell lines from relapsed pB-ALL, including REH, which harbor the TEL-AML1 fusion, and 697, which harbor the E2A-PBX1 fusion. We assessed leukemia phenotypes in vitro and leukemic engraftment in vivo. To dissect molecular mechanisms, we performed RNA sequencing (RNAseq) and applied in silico pathway analysis. To validate these pathways in human pB-ALL, we assessed gene expression and clinical outcomes in independent cohorts. The Broad Institute Connectivity Map (CMAP) was applied to identify drugs to target HMGA1 networks.Results:HMGA1 is overexpressed in pB-ALL in independent cohorts with highest levels at relapse. Decreasing HMGA1 expression via CRISPR/Cas9 inactivation or shRNA-mediated gene silencing in relapsed pB-ALL cell lines (REH, 697) disrupts proliferation, decreases the frequency of cells in S phase concurrent with increases in G0/G1, enhances apoptosis, and impairs clonogenicity. To assess HMGA1 function in vivo, we compared leukemogenesis following tail vein injection of pB-ALL cell lines with or without HMGA1 depletion in immunodeficient mice (NOD/SCID/IL2 receptor gamma null). Survival was prolonged in mice injected with either pB-ALL cell line (REH, 697) after HMGA1 depletion. Further, leukemic cells that ultimately engraft show increased HMGA1 expression relative to the pool of injected cells with HMGA1 silencing, suggesting that escape from HMGA1 silencing was required for engraftment. RNAseq revealed transcriptional networks governed by HMGA1 that regulate proliferation (G2M checkpoint, E2F), RAS/ERK signaling, hematopoietic stem cells, and ETV5 (ETS variant 5 transcription factor) targets. Given its association with aggressive ALL harboring the BCR-ABL fusion, we focused on the ETV5 gene. CRISPR/Cas9 inactivation or gene silencing of ETV5 in relapsed pB-ALL cell lines (REH, 697) decreases proliferation and clonogenicity in vitro, while delaying leukemogenesis in vivo. Further, restoring ETV5 expression in pB-ALL cell lines with HMGA1 silencing partially rescues anti-leukemogenic effects of HMGA1 depletion. Mechanistically, HMGA1 binds to AT-rich regions within the ETV5 promoter (-0.7 kb and -0.2 kb) and recruits active histone marks (H3K27Ac, H3K4me3, H3K4me1) to induce ETV5. Epigenetic drugs predicted to target HMGA1-ETV5 networks synergize with HMGA1 silencing in cytotoxicity assays with pB-ALL cell lines. Most importantly, HMGA1 and ETV5 are co-expressed and up-regulated in primary blasts from children with pB-ALL with highest levels at relapse, thus underscoring the significance of this pathway in relapsed pediatric B-ALL.Conclusions: We discovered a previously unknown epigenetic program whereby HMGA1 up-regulates ETV5 networks by binding to chromatin and recruiting active histone marks to the ETV5 promoter. Both HMGA1 and ETV5 are up-regulated at relapse. Finally, the HMGA1-ETV5 axis can be targeted by epigenetic drugs (HDAC inhibitors) that synergize with HMGA1 depletion. Our findings reveal the HMGA1-ETV5 axis as a key molecular switch in relapsed pB-ALL and rational therapeutic target to treat or prevent relapse. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.