The high mobility group A1 gene: transforming inflammatory signals into cancer?

From metabolism to malignancy: the multifaceted role of PGC1α in cancer

PGC1α, a central player in mitochondrial biology, holds a complex role in the metabolic shifts seen in cancer cells. While its dysregulation is common across major cancers, its impact varies. In some cases, downregulation promotes aerobic glycolysis and progression, whereas in others, overexpression escalates respiration and aggression. PGC1α's interactions with distinct signaling pathways and transcription factors further diversify its roles, often in a tissue-specific manner. Understanding these multifaceted functions could unlock innovative therapeutic strategies. However, challenges exist in managing the metabolic adaptability of cancer cells and refining PGC1α-targeted approaches. This review aims to collate and present the current knowledge on the expression patterns, regulators, binding partners, and roles of PGC1α in diverse cancers. We examined PGC1α's tissue-specific functions and elucidated its dual nature as both a potential tumor suppressor and an oncogenic collaborator. In cancers where PGC1α is tumor-suppressive, reinstating its levels could halt cell proliferation and invasion, and make the cells more receptive to chemotherapy. In cancers where the opposite is true, halting PGC1α's upregulation can be beneficial as it promotes oxidative phosphorylation, allows cancer cells to adapt to stress, and promotes a more aggressive cancer phenotype. Thus, to target PGC1α effectively, understanding its nuanced role in each cancer subtype is indispensable. This can pave the way for significant strides in the field of oncology.

HMGA1 sensitizes esophageal squamous cell carcinoma to mTOR inhibitors through the ETS1-FKBP12 axis

Esophageal carcinoma is amongst the prevalent malignancies worldwide, characterized by unclear molecular classifications and varying clinical outcomes. The PI3K/AKT/mTOR signaling, one of the frequently perturbed dysregulated pathways in human malignancies, has instigated the development of various inhibitory agents targeting this pathway, but many ESCC patients exhibit intrinsic or adaptive resistance to these inhibitors. Here, we aim to explore the reasons for the insensitivity of ESCC patients to mTOR inhibitors. We assessed the sensitivity to rapamycin in various ESCC cell lines by determining their respective IC50 values and found that cells with a low level of HMGA1 were more tolerant to rapamycin. Subsequent experiments have supported this finding. Through a transcriptome sequencing, we identified a crucial downstream effector of HMGA1, FKBP12, and found that FKBP12 was necessary for HMGA1-induced cell sensitivity to rapamycin. HMGA1 interacted with ETS1, and facilitated the transcription of FKBP12. Finally, we validated this regulatory axis in in vivo experiments, where HMGA1 deficiency in transplanted tumors rendered them resistance to rapamycin. Therefore, we speculate that mTOR inhibitor therapy for individuals exhibiting a reduced level of HMGA1 or FKBP12 may not work. Conversely, individuals exhibiting an elevated level of HMGA1 or FKBP12 are more suitable candidates for mTOR inhibitor treatment.

IKBKE promotes the ZEB2-mediated EMT process by phosphorylating HMGA1a in glioblastoma

IKBKE (Inhibitor of Nuclear Factor Kappa-B Kinase Subunit Epsilon) is an important oncogenic protein in a variety of tumors, which can promote tumor growth, proliferation, invasion and drug resistance, and plays a critical regulatory role in the occurrence and progression of malignant tumors. HMGA1a (High Mobility Group AT-hook 1a) functions as a cofactor for proper transcriptional regulation and is highly expressed in multiple types of tumors. ZEB2 (Zinc finger E-box Binding homeobox 2) exerts active functions in epithelial mesenchymal transformation (EMT). In our current study, we confirmed that IKBKE can increase the proliferation, invasion and migration of glioblastoma cells. We then found that IKBKE can phosphorylate HMGA1a at Ser 36 and/or Ser 44 sites and inhibit the degradation process of HMGA1a, and regulate the nuclear translocation of HMGA1a. Crucially, we observed that HMGA1a can regulate ZEB2 gene expression by interacting with ZEB2 promoter region. Hence, HMGA1a was found to promote the ZEB2-related metastasis. Consequently, we demonstrated that IKBKE can exert its oncogenic functions via the IKBKE/HMGA1a/ZEB2 signalling axis, and IKBKE may be a prominent biomarker for the treatment of glioblastoma in the future.

STMN1 Promotes Tumor Metastasis in Non-small Cell Lung Cancer Through Microtubule-dependent And Nonmicrotubule-dependent Pathways

The relationship between STMN1 and cancer metastasis is controversial. The purpose of this study was to explore the role and mechanism of STMN1 in NSCLC metastasis. In this study, we reported that STMN1 was highly expressed in NSCLC tissues and associated with poor prognosis. Both in vivo and in vitro functional assays confirmed that STMN1 promoted NSCLC metastasis. Further studies confirmed that STMN1 promoted cell migration by regulating microtubule stability. The results of Co-IP and LC‒MS/MS illustrated that STMN1 interacts with HMGA1. HMGA1 decreases microtubule stability by regulating the phosphorylation level of STMN1 at Ser16 and Ser38 after interacting with STMN1. This result suggested that STMN1 could be activated by HMGA1 to further promote NSCLC metastasis. Meanwhile, it has been found that STMN1 could promote cell migration by activating the p38MAPK/STAT1 signaling pathway, which is not dependent on microtubule stability. However, activating p38MAPK can decrease microtubule stability by promoting the dephosphorylation of STMN1 at ser16. A positive feedback loop was formed between STMN1 and p38MAPK to synergistically promote cell migration. In summary, our study demonstrated that STMN1 could promote NSCLC metastasis through microtubule-dependent and nonmicrotubule-dependent mechanisms. STMN1 has the potential to be a therapeutic target to inhibit metastasis.

Significance of High-Mobility Group A Protein 2 Expression in Pancreatic Ductal Adenocarcinoma and Ampullary Adenocarcinoma

BACKGROUND/AIMS

Pancreatic and ampullary adenocarcinoma (AAC) are quite resistant to chemotherapy with high metastasis potential. Our study aimed to interpret high-mobility group A protein 2 (HMGA2) expression in benign and precursor pancreatic lesions and pancreatic and ampullary carcinoma and to evaluate its relationship with epithelial-mesenchymal transition (EMT) and clinicopathological parameters.

MATERIALS AND METHODS

In this study, normal-appearing pancreas, chronic pancreatitis (CP), low- (L) and high (H)-grade pancreatic intraepithelial neoplasia (PanIN), pancreatic ductal adenocarcinoma (PDAC), and AAC were evaluated with the immunohistochemical marker of HMGA2. Vimentin and E-cadherin immunohistochemical stains were applied in PDAC and AAC.

RESULTS

The HMGA2 expression was not detected in normal-appearing pancreas, CP, and L-PanIN. A statistically significant expression was observed in PDAC and H-PanIN (P < .001). A statistically significant correlation was found between loss of membranous E-cadherin expression and vimentin positivity and HMGA2 expression (P > .05). The HMGA2 expression was observed to increase the risk of diseaserelated death and decrease overall survival (OS) in AAC and the neoplasia group (P = .002 and P = .016, respectively). There was no significant difference in OS and risk of death in PDAC (P > .05) with respect to HMGA2 positivity.

CONCLUSION

High-mobility group A protein 2 is a helpful immunohistochemical marker in differentiating CP from PDAC. It also plays a role in EMT and may serve as a potential new prognostic agent and therapeutic target in tumors of the periampullary region, especially AAC.

HMGA2 knockdown alleviates the progression of nonalcoholic fatty liver disease (NAFLD) by downregulating SNAI2 expression

Non-alcoholic fatty liver disease (NAFLD) is a complex disease that is considered as the next major health epidemic with alarmingly increasing global prevalence. To explore the pathogenesis of NAFLD, data from GSE118892 were analyzed. High mobility group AT-hook 2 (HMGA2), a member of the high mobility group family, is declined in liver tissues of NAFLD rats. However, its role in NAFLD remains unknown. This study attempted to identify the multiple roles of HMGA2 in NAFLD process. NAFLD was induced in rats using a high-fat diet (HFD). In vivo, HMGA2 knockdown using adenovirus system attenuated liver injury and liver lipid deposition, accompanied by decreased NAFLD score, increased liver function, and decreased CD36 and FAS, indicating the deceleration of NAFLD progression. Moreover, HMGA2 knockdown restrained liver inflammation by decreasing the expression of related inflammatory factors. Importantly, HMGA2 knockdown attenuated liver fibrosis via downregulating the expression of fibrous proteins, and inhibiting the activation of TGF-β1/SMAD signaling pathway. In vitro, HMGA2 knockdown relieved palmitic acid (PA)-induced hepatocyte injury and attenuated TGF-β1-induced liver fibrosis, consistent with in vivo findings. Strikingly, HMGA2 activated the transcription of SNAI2, which was evidenced by the dual luciferase assays. Moreover, HMGA2 knockdown largely downregulated SNAI2 levels. Indeed, SNAI2 overexpression effectively blocked the inhibitory effect of HMGA2 knockdown on NAFLD. Totally, our findings reveal that HMGA2 knockdown alleviates the progression of NAFLD by directly regulating the transcription of SNAI2. HMGA2 inhibition may emerge as a potential therapeutic target for NAFLD.

HMGA1 induces FGF19 to drive pancreatic carcinogenesis and stroma formation

High mobility group A1 (HMGA1) chromatin regulators are upregulated in diverse tumors where they portend adverse outcomes, although how they function in cancer remains unclear. Pancreatic ductal adenocarcinomas (PDACs) are highly lethal tumors characterized by dense desmoplastic stroma composed predominantly of cancer-associated fibroblasts and fibrotic tissue. Here, we uncover an epigenetic program whereby HMGA1 upregulates FGF19 during tumor progression and stroma formation. HMGA1 deficiency disrupts oncogenic properties in vitro while impairing tumor inception and progression in KPC mice and subcutaneous or orthotopic models of PDAC. RNA sequencing revealed HMGA1 transcriptional networks governing proliferation and tumor-stroma interactions, including the FGF19 gene. HMGA1 directly induces FGF19 expression and increases its protein secretion by recruiting active histone marks (H3K4me3, H3K27Ac). Surprisingly, disrupting FGF19 via gene silencing or the FGFR4 inhibitor BLU9931 recapitulates most phenotypes observed with HMGA1 deficiency, decreasing tumor growth and formation of a desmoplastic stroma in mouse models of PDAC. In human PDAC, overexpression of HMGA1 and FGF19 defines a subset of tumors with extremely poor outcomes. Our results reveal what we believe is a new paradigm whereby HMGA1 and FGF19 drive tumor progression and stroma formation, thus illuminating FGF19 as a rational therapeutic target for a molecularly defined PDAC subtype.

HMGA1 Promotes Macrophage Recruitment via Activation of NF-κB-CCL2 Signaling in Hepatocellular Carcinoma

Background

Tumor-associated macrophages (TAMs) are known to generate an immune-suppressive tumor microenvironment (TME) and promote tumor progression. Hepatocellular carcinoma (HCC) is a devastating disease that evolves in the background of chronic inflammatory liver damage. In this study, we aimed to uncover the mechanism by which HCC cells recruit macrophages into the TME.

Methods

Bioinformatic analysis was performed to identify differentially expressed genes related to macrophage infiltration. An orthotopic HCC xenograft model was used to determine the role of macrophages in HCC tumor growth. Clodronate liposomes were used to delete macrophages. Western blotting analysis, quantitative real-time PCR, and enzyme-linked immunosorbent assay were performed to determine the underlying mechanisms.

Results

The high mobility group A1 (HMGA1) gene was identified as a putative modulator of macrophage infiltration in HCC. Deletion of macrophages with clodronate liposomes significantly abrogated the tumor-promoting effects of HMGA1 on HCC growth. Mechanistically, HMGA1 can regulate the expression of C-C Motif Chemokine Ligand 2 (CCL2), also referred to as monocyte chemoattractant protein 1 (MCP1), which is responsible for macrophage recruitment. Moreover, NF-κB was required for HMGA1-mediated CCL2 expression. Pharmacological or genetic inhibition of NF-κB largely blocked CCL2 levels in HMGA1-overexpressing HCC cells.

Conclusions

This study reveals HMGA1 as a crucial regulator of macrophage recruitment by activating NF-κB-CCL2 signaling, proves that HMGA1-induced HCC aggressiveness dependents on the macrophage, and provide an attractive target for therapeutic interventions in HCC.

HMGA1 chromatin regulators induce transcriptional networks involved in GATA2 and proliferation during MPN progression

Myeloproliferative neoplasms (MPNs) transform to myelofibrosis (MF) and highly lethal acute myeloid leukemia (AML), although the actionable mechanisms driving progression remain elusive. Here, we elucidate the role of the high mobility group A1 (HMGA1) chromatin regulator as a novel driver of MPN progression. HMGA1 is upregulated in MPN, with highest levels after transformation to MF or AML. To define HMGA1 function, we disrupted gene expression via CRISPR/Cas9, short hairpin RNA, or genetic deletion in MPN models. HMGA1 depletion in JAK2V617F AML cell lines disrupts proliferation, clonogenicity, and leukemic engraftment. Surprisingly, loss of just a single Hmga1 allele prevents progression to MF in JAK2V617F mice, decreasing erythrocytosis, thrombocytosis, megakaryocyte hyperplasia, and expansion of stem and progenitors, while preventing splenomegaly and fibrosis within the spleen and BM. RNA-sequencing and chromatin immunoprecipitation sequencing revealed HMGA1 transcriptional networks and chromatin occupancy at genes that govern proliferation (E2F, G2M, mitotic spindle) and cell fate, including the GATA2 master regulatory gene. Silencing GATA2 recapitulates most phenotypes observed with HMGA1 depletion, whereas GATA2 re-expression partially rescues leukemogenesis. HMGA1 transactivates GATA2 through sequences near the developmental enhancer (+9.5), increasing chromatin accessibility and recruiting active histone marks. Further, HMGA1 transcriptional networks, including proliferation pathways and GATA2, are activated in human MF and MPN leukemic transformation. Importantly, HMGA1 depletion enhances responses to the JAK2 inhibitor, ruxolitinib, preventing MF and prolonging survival in murine models of JAK2V617F AML. These findings illuminate HMGA1 as a key epigenetic switch involved in MPN transformation and a promising therapeutic target to treat or prevent disease progression.

miR-214-3p Is Commonly Downregulated by EWS-FLI1 and by CD99 and Its Restoration Limits Ewing Sarcoma Aggressiveness

Simple Summary

Ewing’s sarcoma (EWS), the second most frequent primary tumor of bone in the pediatric population, is a very aggressive, undifferentiated mesenchymal malignancy with a high tendency to develop lung and/or bone metastasis. The prognosis of patients with metastasis remains dismal, and new strategies are needed to control the dissemination of EWS cells. EWS is driven by alterations induced by the EWS-FLI1 chimera which acts as an aberrant transcriptional factor that induces the complete reprograming of the gene expression. EWS cells are also characterized by high expression of CD99, a cell surface molecule that interacts with EWS-FLI1 to sustain EWS malignancy. This study shows that miR-214-3p is a common mediator of EWS-FLI1 and CD99, and we report that miR-214-3p acts as on oncosuppressor in EWS. MiR-214-3p is constitutively repressed in cell lines and clinical samples but is re-expressed after the silencing of EWS-FLI1 and/or CD99. The restoration of miR-214-3p limits EWS cell growth and migration and represses the expression of its target HMGA1, supporting the potential role of this miRNA as a marker of tumor aggressiveness.

Abstract

Ewing’s sarcoma (EWS), an aggressive pediatric bone and soft-tissue sarcoma, has a very stable genome with very few genetic alterations. Unlike in most cancers, the progression of EWS appears to depend on epigenetic alterations. EWS–FLI1 and CD99, the two hallmarks of EWS, are reported to severely impact the malignancy of EWS cells, at least partly by regulating the expression of several types of non-coding RNAs. Here, we identify miR-214-3p as a common mediator of either EWS-FLI1 or CD99 by in silico analysis. MiR-214-3p expression was lower in EWS cells and in clinical samples than in bone marrow mesenchymal stem cells, and this miRNA was barely expressed in metastatic lesions. Silencing of EWS-FLI1 or CD99 restored the expression of miR-214-3p, leading to a reduced cell growth and migration. Mechanistically, miR-214-3p restoration inhibits the expression of the high-mobility group AT-hook 1 (HMGA1) protein, a validated target of miR-214-3p and a major regulator of the transcriptional machinery. The decrease in HMGA1 expression reduced the growth and the migration of EWS cells. Taken together, our results support that the miR-214-3p is constitutively repressed by both EWS-FLI1 and CD99 because it acts as an oncosuppressor limiting the dissemination of EWS cells.

Gene Expression over Time during Cell Transformation Due to Non-Genotoxic Carcinogen Treatment of Bhas 42 Cells

The Bhas 42 cell transformation assay (Bhas 42 CTA) is the first Organization for Economic Cooperation and Development (OECD)-certificated method used as a specific tool for the detection of the cell-transformation potential of tumor-promoting compounds, including non-genotoxic carcinogens (NGTxCs), as separate from genotoxic carcinogens. This assay offers the great advantage of enabling the phenotypic detection of oncotransformation. A key benefit of using the Bhas 42 CTA in the study of the cell-transformation mechanisms of tumor-promoting compounds, including non-genotoxic carcinogens, is that the cell-transformation potential of the chemical can be detected directly without treatment with a tumor-initiating compound since Bhas 42 cell line was established by transfecting the v-Ha-ras gene into a mouse fibroblast cloned cell line. Here, we analyzed the gene expression over time, using DNA microarrays, in Bhas 42 cells treated with the tumor-promoting compound 12-O-tetradecanoylphorbol-13-acetate (TPA), and NGTxC, with a total of three repeat experiments. This is the first paper to report on gene expression over time during the process of cell transformation with only a tumor-promoting compound. Pathways that were activated or inactivated during the process of cell transformation in the Bhas 42 cells treated with TPA were related not only directly to RAS but also to various pathways in the hallmarks of cancer.

miR-142-3p simultaneously targets HMGA1, HMGA2, HMGB1, and HMGB3 and inhibits tumorigenic properties and in-vivo metastatic potential of human cervical cancer cells

AIMS

High-mobility group (HMG) proteins are oncogenic in different cancers, including cervical cancer; silencing their individual expression using sh-RNAs, siRNAs, and miRNAs has had anti-tumorigenic effects, but the consequences of their collective downregulation are not known. Since multiple gene targeting is generally very effective in cancer therapy, the present study highlighted the consequences of silencing the expression of HMGA1, A2, B1, and B3 using sh-RNAs or miR-142-3p (that can potentially target HMGA1, A2, B1, and B3) in cervical cancer cell lines.

MAIN METHODS

3' UTR luciferase reporter assays were performed to validate HMGA1, A2, B1, and B3 as targets of miR-142-3p in human cervical cancer cells. Annexin V/PI dual staining and flow cytometry analyses were used to detect apoptotic cells. miR-142-3p-mediated regulation of cell death, colony formation, migration, and invasion was investigated in human cervical cancer cells together with in vivo metastasis in zebrafish.

KEY FINDINGS

Concurrent knockdown of HMGA1, A2, B1, and B3 through their corresponding sh-RNAs inhibited cell viability and colony formation but induced apoptosis, and these effects were relatively reduced upon their individual knockdown. miR-142-3p targeted HMGA1, A2, B1, and B3 by binding to their 3'UTRs and induced apoptosis but inhibited proliferation, migration, and invasion of human cervical cancer cells. In addition, miR-142-3p expression decreased phospho-p65 and EMT-related proteins in cervical cancer cells and their in vivo metastatic potential upon implantation in zebrafish.

SIGNIFICANCE

These findings suggest that miR-142-3p acts as a tumor-suppressive miRNA by targeting HMGA1, A2, B1, and B3 and may serve as a potential therapeutic agent in human cervical cancer.

HMGA1 Has Predictive Value in Response to Chemotherapy in Gastric Cancer

Gastric cancer is a serious health problem worldwide. Although its incidence is decreasing, the five-year survival rate remains low. Thus, it is essential to identify new biomarkers that could promote better diagnosis and treatment of patients with gastric cancer. High-mobility group AT-hook 1 (HMGA1) is a non-histone, chromatin-binding protein that has been found overexpressed in several tumor types. It has been correlated with invasion, metastasis, and drug resistance, leading to worse patient survival. The aim of this work was to evaluate the clinical value of HMGA1 in gastric cancer. HMGA1 expression was analyzed by immunohistochemistry in a single hospital series (n = 323) of gastric adenocarcinoma cases (stages I to IV) with clinicopathological and treatment data. In this series, HMGA1 expression showed no significant relevance as a prognostic biomarker. Nevertheless, a significantly better overall survival was observed in cases with high levels of HMGA1 when they were treated with chemotherapy, compared to the nontreated ones, implying that they can benefit more from treatment than patients with low expression of HMGA1. We thereby show for the first time that HMGA1 expression has a substantial value as a biomarker of response to chemotherapy in gastric cancer.

Advances in polycythemia vera and lessons for acute leukemia

The myeloproliferative neoplasms (MPN), polycythemia vera (PV), essential thrombocytosis and primary myelofibrosis, are an unusual group of myeloid neoplasms, which arise in a pluripotent hematopoietic stem cell (HSC) due to gain of function driver mutations in the JAK2, CALR and MPL genes that constitutively activate JAK2, the cognate tyrosine kinase of the type 1 hematopoietic growth factor (HGF) receptors. PV is the ultimate phenotypic expression of constitutive JAK2 activation since it alone of the three MPN is characterized by overproduction of normal red cells, white cells and platelets. Paradoxically, however, although PV is a panmyelopathy involving myeloid, erythroid and megakaryocytic progenitor cells, pluripotent HSC only express a single type of HGF receptor, the thrombopoietin receptor, MPL. In this review, the basis for how a pluripotent HSC with one type of HGF can give rise to three separate types of myeloid cells will be explained and it will be demonstrated that PV is actually a hormone-sensitive disorder, characterized by elevated thrombopoietin levels. Finally, it will be shown that the most common form of acute leukemia in PV is due to the inappropriate use of chemotherapy, including hydroxyurea, which facilitates expansion of DNA-damaged, mutated HSC at the expense of their normal counterparts.

HMGA1, Moonlighting Protein Function, and Cellular Real Estate: Location, Location, Location!

The gene encoding the High Mobility Group A1 (HMGA1) chromatin remodeling protein is upregulated in diverse cancers where high levels portend adverse clinical outcomes. Until recently, HMGA1 was assumed to be a nuclear protein exerting its role in cancer by transcriptionally modulating gene expression and downstream signaling pathways. However, the discovery of an extracellular HMGA1-RAGE autocrine loop in invasive triple-negative breast cancer (TNBC) cell lines implicates HMGA1 as a "moonlighting protein" with different functions depending upon cellular location. Here, we review the role of HMGA1, not only as a chromatin regulator in cancer and stem cells, but also as a potential secreted factor that drives tumor progression. Prior work found that HMGA1 is secreted from TNBC cell lines where it signals through the receptor for advanced glycation end products (RAGE) to foster phenotypes involved in tumor invasion and metastatic progression. Studies in primary TNBC tumors also suggest that HMGA1 secretion associates with distant metastasis in TNBC. Given the therapeutic potential to target extracellular proteins, further work to confirm this role in other contexts is warranted. Indeed, crosstalk between nuclear and secreted HMGA1 could change our understanding of tumor development and reveal novel therapeutic opportunities relevant to diverse human cancers overexpressing HMGA1.

Discovering the Protective Effects of Resveratrol on Aflatoxin B1-Induced Toxicity: A Whole Transcriptomic Study in a Bovine Hepatocyte Cell Line

Aflatoxin B1 (AFB1) is a natural feed and food contaminant classified as a group I carcinogen for humans. In the dairy industry, AFB1 and its derivative, AFM1, are of concern for the related economic losses and their possible presence in milk and dairy food products. Among its toxic effects, AFB1 can cause oxidative stress. Thus, dietary supplementation with natural antioxidants has been considered among the strategies to mitigate AFB1 presence and its toxicity. Here, the protective role of resveratrol (R) has been investigated in a foetal bovine hepatocyte cell line (BFH12) exposed to AFB1, by measuring cytotoxicity, transcriptional changes (RNA sequencing), and targeted post-transcriptional modifications (lipid peroxidation, NQO1 and CYP3A enzymatic activity). Resveratrol reversed the AFB1-dependent cytotoxicity. As for gene expression, when administered alone, R induced neglectable changes in BFH12 cells. Conversely, when comparing AFB1-exposed cells with those co-incubated with R+AFB1, greater transcriptional variations were observed (i.e., 840 DEGs). Functional analyses revealed that several significant genes were involved in lipid biosynthesis, response to external stimulus, drug metabolism, and inflammatory response. As for NQO1 and CYP3A activities and lipid peroxidation, R significantly reverted variations induced by AFB1, mostly corroborating and/or completing transcriptional data. Outcomes of the present study provide new knowledge about key molecular mechanisms involved in R antioxidant-mediated protection against AFB1 toxicity.

Interception Targets of Angelica Gigas Nakai Root Extract versus Pyranocoumarins in Prostate Early Lesions and Neuroendocrine Carcinomas in TRAMP Mice

We reported efficacy of Angelica gigas Nakai (AGN) root ethanol extract and equimolar decursin (D)/decursinol angelate (DA) through daily gavage starting at 8 weeks of age (WOA) to male transgenic adenocarcinoma of mouse prostate (TRAMP) mice such that these modalities suppressed precancerous epithelial lesions in their dorsolateral prostate (DLP) to similar extent, but AGN extract was better than the D/DA mixture at promoting the survival of mice bearing prostate neuroendocrine carcinomas to 28 WOA. Here, we compared by microarray hybridization the mRNA levels in pooled DLP tissues and individual neuroendocrine carcinomas to characterize potential molecular targets of AGN extract and D/DA. Clustering and principal component analyses supported distinct gene expression profiles of TRAMP DLP versus neuroendocrine carcinomas. Pathway Enrichment, Gene Ontology, and Ingenuity Pathway Analyses of differential genes indicated that AGN and D/DA affected chiefly processes of lipid and mitochondrial energy metabolism and oxidation-reduction in TRAMP DLP, while AGN affected neuronal signaling, immune systems and cell cycling in neuroendocrine carcinomas. Protein-Protein Interaction Network analysis predicted and reverse transcription-PCR verified multiple hub genes common in the DLP of AGN- and D/DA-treated TRAMP mice at 28 WOA and select hub genes attributable to the non-D/DA AGN components. The vast majority of hub genes in the AGN-treated neuroendocrine carcinomas differed from those in TRAMP DLP. In summary, the transcriptomic approach illuminated vastly different signaling pathways and networks, cellular processes, and hub genes of two TRAMP prostate malignancy lineages and their associations with the interception efficacy of AGN and D/DA. PREVENTION RELEVANCE: This study explores potential molecular targets associated with in vivo activity of AGN root alcoholic extract and its major pyranocoumarins to intercept precancerous epithelial lesions and early malignancies of the prostate. Without an ethically-acceptable, clearly defined cancer initiation risk reduction strategy available for the prostate, using natural products like AGN to delay formation of malignant tumors could be a plausible approach for prostate cancer prevention.

HMGA1-TRIP13 axis promotes stemness and epithelial mesenchymal transition of perihilar cholangiocarcinoma in a positive feedback loop dependent on c-Myc

Background

Cholangiocarcinoma is a highly malignant cancer with very dismal prognosis. Perihilar cholangiocarcinoma(pCCA) accounts for more than 50% of all cholangiocarcinoma and is well-characterized for its low rate of radical resection. Effects of radiotherapy and chemotherapy of pCCA are very limited.

Methods

Here we screened potential biomarkers of pCCA with transcriptome sequencing and evaluated the prognostic significance of HMGA1 in a large cohort pCCA consisting of 106 patients. With bioinformatics and in vitro/vivo experiments, we showed that HMGA1 induced tumor cell stemness and epithelial-mesenchymal-transition (EMT), and thus facilitated proliferation, migration and invasion by promoting TRIP13 transcription. Moreover, TRIP13 was also an unfavorable prognostic biomarker of pCCA, and double high expression of HMGA1/TRIP13 could predict prognosis more sensitively. TRIP13 promoted pCCA progression by suppressing FBXW7 transcription and stabilizing c-Myc. c-Myc in turn induced the transcription and expression of both HMGA1 and TRIP13, indicating that HMGA-TRIP13 axis facilitated pCCA stemness and EMT in a positive feedback pathway.

Conclusions

HMGA1 and TRIP13 were unfavorable prognostic biomarkers of pCCA. HMGA1 enhanced pCCA proliferation, migration, invasion, stemness and EMT, by inducing TRIP13 expression, suppressing FBXW7 expression and stabilizing c-Myc. Moreover, c-Myc can induce the transcription of HMGA1 and TRIP13, suggesting that HMGA-TRIP13 axis promoted EMT and stemness in a positive feedback pathway dependent on c-Myc.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01890-1.

HMGA1 Induction of miR-103/107 Forms a Negative Feedback Loop to Regulate Autophagy in MPTP Model of Parkinson's Disease

Autophagy dysfunction has been directly linked with the onset and progression of Parkinson’s disease (PD), but the underlying mechanisms are not well understood. High-mobility group A1 (HMGA1), well-known chromatin remodeling proteins, play pivotal roles in diverse biological processes and diseases. Their function in neural cell death in PD, however, have not yet been fully elucidated. Here, we report that HMGA1 is highly induced during dopaminergic cell death in vitro and mice models of PD in vivo. Functional studies using genetic knockdown of endogenous HMGA1 show that HMGA1 signaling inhibition accelerates neural cell death, at least partially through aggravating MPP⁺-induced autophagic flux reduction resulting from partial block in autophagic flux at the terminal stages, indicating a novel potential neuroprotective role for HMGA1 in dopaminergic neurons death. MicroRNA-103/107 (miR-103/107) family, which is highly expressed in neuron, coordinately ensures proper end-stage autophagy. We further illustrate that MPP⁺/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced HMGA1 elevation counterparts the effect of miR-103/107 downregulation by directly binding to their promoters, respectively, sustaining their expression in MPP⁺-damaged MN9D cells and modulates autophagy through CDK5R1/CDK5 signaling pathway. We also find that HMGA1 is a direct target of miR-103/107 family. Thus, our results suggest that HMGA1 forms a negative feedback loop with miR-103/107-CDK5R1/CDK5 signaling to regulate the MPP⁺/MPTP-induced autophagy impairment and neural cell death. Collectively, we identify a paradigm for compensatory neuroprotective HMGA1 signaling in dopaminergic neurons that could have important therapeutic implications for PD.

The midlife transition and the risk of cardiovascular disease and cancer Part I: magnitude and mechanisms

Heart disease and cancer are the leading causes of death in the United States. In women, the clinical appearance of both entities-coronary heart disease and cancer (breast, endometrium, and ovary)-escalate during the decades of the midlife transition encompassing the menopause. In addition to the impact of aging, during the interval between the age of 40 and 65 years, the pathophysiologic components of metabolic syndrome also emerge and accelerate. These include visceral adiposity (measured as waist circumference), hypertension, diabetes, and dyslipidemia. Osteoporosis, osteoarthritis, sarcopenia, depression, and even cognitive decline and dementia appear, and most, if not all, are considered functionally related. Two clinical reports confirm the interaction linking the emergence of disease: endometrial cancer and metabolic syndrome. One describes the discovery of unsuspected endometrial cancer in a large series of elective hysterectomies performed in aged and metabolically susceptible populations. The other is from the Women's Health Initiative Observational Study, which found a positive interaction between endometrial cancer and metabolic syndrome regardless of the presence or absence of visceral adiposity. Both provide additional statistical support for the long-suspected causal interaction among the parallel but variable occurrence of these common entities-visceral obesity, heart disease, diabetes, cancer, and the prevalence of metabolic syndrome. Therefore, 2 critical clinical questions require analysis and answers: 1: Why do chronic diseases of adulthood-metabolic, cardiovascular, endocrine-and, in women, cancers of the breast and endometrium (tissues and tumors replete with estrogen receptors) emerge and their incidence trajectories accelerate during the postmenopausal period when little or no endogenous estradiol is available, and yet the therapeutic application of estrogen stimulates their appearance? 2: To what extent should identification of these etiologic driving forces require modification of the gynecologist's responsibilities in the care of our patients in the postreproductive decades of the female life cycle? Part l of this 2-part set of "expert reviews" defines the dimensions, gravity, and interactive synergy of each clinical challenge gynecologists face while caring for their midlife (primarily postmenopausal) patients. It describes the clinically identifiable, potentially treatable, pathogenic mechanisms driving these threats to quality of life and longevity. Part 2 (accepted, American Journal of Obstetrics & Gynecology) identifies 7 objectives of successful clinical care, offers "triage" prioritization targets, and provides feasible opportunities for insertion of primary preventive care initiatives. To implement these goals, a reprogrammed, repurposed office visit is described.

HMGA Proteins in Hematological Malignancies

The high mobility group AT-Hook (HMGA) proteins are a family of nonhistone chromatin remodeling proteins known as "architectural transcriptional factors". By binding the minor groove of AT-rich DNA sequences, they interact with the transcription apparatus, altering the chromatin modeling and regulating gene expression by either enhancing or suppressing the binding of the more usual transcriptional activators and repressors, although they do not themselves have any transcriptional activity. Their involvement in both benign and malignant neoplasias is well-known and supported by a large volume of studies. In this review, we focus on the role of the HMGA proteins in hematological malignancies, exploring the mechanisms through which they enhance neoplastic transformation and how this knowledge could be exploited to devise tailored therapeutic strategies.

Clinical Implications of Extracellular HMGA1 in Breast Cancer

The unconventional secretion of proteins is generally caused by cellular stress. During the tumorigenesis, tumor cells experience high levels of stress, and the secretion of some theoretically intracellular proteins is activated. Once in the extracellular space, these proteins play different paracrine and autocrine roles and could represent a vulnerability of cancer. One of these proteins is the high mobility group A1 (HMGA1), which is frequently overexpressed in tumors and presents a low expression in normal adult tissues. We have recently described that HMGA1 establishes an autocrine loop in invasive triple-negative breast cancer (TNBC) cells. The secretion of HMGA1 and its binding to the receptor for advanced glycation end products (RAGE) mediates the migration, invasion, and metastasis of TNBC cells and predicts the onset of metastasis in these patients. In this review, we summarized different strategies to exploit the novel tumorigenic phenotype mediated by extracellular HMGA1. We envisioned future clinical applications where the association between its change in subcellular localization and breast cancer progression could be used to predict tumor aggressiveness and guide treatment decisions. Furthermore, we proposed that targeting extracellular HMGA1 as monotherapy using monoclonal antibodies, or in combination with chemotherapy and other targeted therapies, could bring new therapeutic options for TNBC patients.

HMGA1 exacerbates tumor progression by activating miR-222 through PI3K/Akt/MMP-9 signaling pathway in uveal melanoma

High-mobility group A1 (HMGA1), an architectural transcription factor, participates in different human tumors' biological progression. HMGA1 overexpression is associated with malignant cellular behavior in a wide range of cancers but the underlying mechanism remains poorly illuminated. In this study, we showed PI3K/Akt/MMP9 pathway activity could be positively regulated by HMGA1 using western blotting, real-time polymerase chain reaction (RT-PCR) and immunochemistry both in vitro (C918 and MUM-2B cell lines) and in vivo (xenograft mouse model). Later, MiRTarBase was used to identify the relationship between HMGA1 and miR-222-3p, we found miR-222 is positively regulated by HMGA1. Moreover, the proliferation and migration of UM cells significantly increased in the miR-222 mimics group and decreased in the miR-222 inhibitor group detected by the Annexin V-FITC apoptosis detection kit, CCK-8 and scratch wound-healing. The p-PI3K, p-Akt and MMP9 expressions were elevated in UM cells transfected with miR-222 mimics, and suppressed in the miR-222 inhibitor group. Together, our study highlights that HMGA1 acts as a pivotal regulator in UM tumor growth, proposing a critical viewpoint that HMGA1 expedites progression through the PI3K/Akt/MMP9 pathway and oncogenic miR-222 in UM.

Overexpression of HMGA1 Figures as a Potential Prognostic Factor in Endometrioid Endometrial Carcinoma (EEC)

Endometrioid endometrial carcinomas (EEC) are the most common malignant gynecologic tumors. Despite the increase in EEC molecular knowledge, the identification of new biomarkers involved in disease's development and/or progression would represent an improvement in its course. High-mobility group A protein (HMGA) family members are frequently overexpressed in a wide range of malignancies, correlating with a poor prognosis. Thus, the aim of this study was to analyze HMGA1 and HMGA2 expression pattern and their potential role as EEC biomarkers. HMGA1 and HMGA2 expression was initially evaluated in a series of 46 EEC tumors (stages IA to IV), and the findings were then validated in The Cancer Genome Atlas (TCGA) EEC cohort, comprising 381 EEC tumors (stages IA to IV). Our results reveal that HMGA1 and HMGA2 mRNA and protein are overexpressed in ECC, but only HMGA1 expression is associated with increased histological grade and tumor size. Moreover, HMGA1 but not HMGA2 overexpression was identified as a negative prognostic factor to EEC patients. Finally, a positive correlation between expression of HMGA1 pseudogenes-HMGA1-P6 and HMGA1-P7-and HMGA1 itself was detected, suggesting HMGA1 pseudogenes may play a role in HMGA1 expression regulation in EEC. Thus, these results indicate that HMGA1 overexpression possesses a potential role as a prognostic biomarker for EEC.

Diabetes, Obesity, and Breast Cancer

The rates of obesity and diabetes are increasing worldwide, whereas the age of onset for both obesity and diabetes are decreasing steadily. Obesity and diabetes are associated with multiple factors that contribute to the increased risk of a number of different cancers, including breast cancer. These factors are hyperinsulinemia, elevated IGFs, hyperglycemia, dyslipidemia, adipokines, inflammatory cytokines, and the gut microbiome. In this review, we discuss the current understanding of the complex signaling pathways underlying these multiple factors involved in the obesity/diabetes-breast cancer link, with a focus particularly on the roles of the insulin/IGF system and dyslipidemia in preclinical breast cancer models. We review some of the therapeutic strategies to target these metabolic derangements in cancer. Future research directions and potential therapeutic strategies are also discussed.

Frontline Science: Targeted expression of a dominant-negative high mobility group A1 transgene improves outcome in sepsis

High mobility group (HMG) proteins are a family of architectural transcription factors, with HMGA1 playing a role in the regulation of genes involved in promoting systemic inflammatory responses. We speculated that blocking HMGA1-mediated pathways might improve outcomes from sepsis. To investigate HMGA1 further, we developed genetically modified mice expressing a dominant negative (dn) form of HMGA1 targeted to the vasculature. In dnHMGA1 transgenic (Tg) mice, endogenous HMGA1 is present, but its function is decreased due to the mutant transgene. These mice allowed us to specifically study the importance of HMGA1 not only during a purely pro-inflammatory insult of endotoxemia, but also during microbial sepsis induced by implantation of a bacterial-laden fibrin clot into the peritoneum. We found that the dnHMGA1 transgene was only present in Tg and not wild-type (WT) littermate mice, and the mutant transgene was able to interact with transcription factors (such as NF-κB), but was not able to bind DNA. Tg mice exhibited a blunted hypotensive response to endotoxemia, and less mortality in microbial sepsis. Moreover, Tg mice had a reduced inflammatory response during sepsis, with decreased macrophage and neutrophil infiltration into tissues, which was associated with reduced expression of monocyte chemotactic protein-1 and macrophage inflammatory protein-2. Collectively, these data suggest that targeted expression of a dnHMGA1 transgene is able to improve outcomes in models of endotoxin exposure and microbial sepsis, in part by modulating the immune response and suggest a novel modifiable pathway to target therapeutics in sepsis.

HMGA1 exacerbates tumor growth through regulating the cell cycle and accelerates migration/invasion via targeting miR-221/222 in cervical cancer

High-mobility group AT-hook1 (HMGA1, formerly HMG-I/Y), an architectural transcription factor, participates in a number of tumor biological processes. However, its effect on cervical cancer remains largely indistinct. In this study, we found that HMGA1 was generally overexpressed in cervical cancer tissues and was positively correlated with lymph node metastasis and advanced clinical stage. Via exogenously increasing or decreasing the expression of HMGA1, we showed that HMGA1 affected the proliferation, colony formation, migration and invasion of cervical cancer cells in vitro. Rescue experiments suggested that miR-221/222 could partly reverse HMGA1-mediated migration and invasion processes. Mechanistically, we discovered that HMGA1 accelerated the G1/S phase transition by regulating the expression of cyclin D1 and cyclin E1, which was consistent with the results of the in vivo experiment. Furthermore, we found that HMGA1 regulated the expression of the miR-221/222 cluster at the transcriptional level and that miR-221/222 targeted the 3'UTR of tissue inhibitor of metalloproteinases 3(TIMP3). We propose a fresh perspective that HMGA1 participates in the migration and invasion process via the miR-221/222-TIMP3-MMP2/MMP9 axis in cervical cancer. In summary, our study identified a critical role played by HMGA1 in the progression of cervical cancer and the potential mechanisms by which exerts its effects, suggesting that targeting HMGA1-related pathways could be conducive to the therapies for cervical cancer.

Robust prediction of gene regulation in colorectal cancer tissues from DNA methylation profiles

DNA methylation is recognized as one of several epigenetic regulators of gene expression and as potential driver of carcinogenesis through gene-silencing of tumor suppressors and activation of oncogenes. However, abnormal methylation, even of promoter regions, does not necessarily alter gene expression levels, especially if the gene is already silenced, leaving the exact mechanisms of methylation unanswered. Using a large cohort of matching DNA methylation and gene expression samples of colorectal cancer (CRC; n = 77) and normal adjacent mucosa tissues (n = 108), we investigated the regulatory role of methylation on gene expression. We show that on a subset of genes enriched in common cancer pathways, methylation is significantly associated with gene regulation through gene-specific mechanisms. We built two classification models to infer gene regulation in CRC from methylation differences of tumor and normal tissues, taking into account both gene-silencing and gene-activation effects through hyper- and hypo-methylation of CpGs. The classification models result in high prediction performances in both training and independent CRC testing cohorts (0.92 Collapse

Key Words

• DNA methylation
• Epigenetic regulation
• HMGA1
• colorectal cancer
• gene expression
• prediction model

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MESH Headings

• Colorectal Neoplasms/genetics
• DNA Methylation
• Databases, Genetic
• Epigenesis, Genetic
• Gene Expression Profiling/methods
• Gene Expression Regulation, Neoplastic
• HMGA Proteins/genetics
• Humans
• Machine Learning
• Promoter Regions, Genetic
• Sequence Analysis, DNA/methods

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Affiliation(s)

Hagen Klett German Cancer Consortium (DKTK), Heidelberg, Germany German Cancer Research Center (DKFZ), Heidelberg, Germany Institute of Molecular Medicine and Cell Research, Faculty of Medicine and Medical Center, University of Freiburg, Germany
Yesilda Balavarca Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany
Reka Toth German Cancer Consortium (DKTK), Heidelberg, Germany Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany
Biljana Gigic German Cancer Consortium (DKTK), Heidelberg, Germany Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany Department of General, Visceral and Transplantation Surgery, University Clinic Heidelberg, Heidelberg, Germany
Nina Habermann German Cancer Consortium (DKTK), Heidelberg, Germany Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany
Dominique Scherer German Cancer Consortium (DKTK), Heidelberg, Germany Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany
Petra Schrotz-King German Cancer Consortium (DKTK), Heidelberg, Germany Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany
Alexis Ulrich Department of General, Visceral and Transplantation Surgery, University Clinic Heidelberg, Heidelberg, Germany
Peter Schirmacher German Cancer Consortium (DKTK), Heidelberg, Germany Institute of Pathology, University Clinic Heidelberg, Heidelberg, Germany
Esther Herpel Institute of Pathology, University Clinic Heidelberg, Heidelberg, Germany Tissue Bank of the National Center for Tumor Diseases (NCT) Heidelberg, Germany
Hermann Brenner German Cancer Consortium (DKTK), Heidelberg, Germany Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany
Cornelia M. Ulrich German Cancer Consortium (DKTK), Heidelberg, Germany Division of Preventive Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Heidelberg, Germany Huntsman Cancer Institute and Department of Population Health Sciences, University of Utah, Salt Lake City, UT, USA
Karin B. Michels Institute for Prevention and Cancer Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Germany Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA, USA
Hauke Busch Lübeck Institute of Experimental Dermatology and Institute of Cardiogenetics, University of Lübeck, Lübeck, Germany
Melanie Boerries German Cancer Consortium (DKTK), Heidelberg, Germany German Cancer Research Center (DKFZ), Heidelberg, Germany Institute of Molecular Medicine and Cell Research, Faculty of Medicine and Medical Center, University of Freiburg, Germany

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Lessons from the Crypt: HMGA1-Amping up Wnt for Stem Cells and Tumor Progression

High mobility group A1 (HMGA1) chromatin remodeling proteins are enriched in aggressive cancers and stem cells, although their common function in these settings has remained elusive until now. Recent work in murine intestinal stem cells (ISC) revealed a novel role for Hmga1 in enhancing self-renewal by amplifying Wnt signaling, both by inducing genes expressing Wnt agonist receptors and Wnt effectors. Surprisingly, Hmga1 also "builds" a stem cell niche by upregulating Sox9, a factor required for differentiation to Paneth cells; these cells constitute an epithelial niche by secreting Wnt and other factors to support ISCs. HMGA1 is also highly upregulated in colon cancer compared with nonmalignant epithelium and SOX9 becomes overexpressed during colon carcinogenesis. Intriguingly, HMGA1 is overexpressed in diverse cancers with poor outcomes, where it regulates developmental genes. Similarly, HMGA1 induces genes responsible for pluripotency and self-renewal in embryonic stem cells. These findings demonstrate that HMGA1 maintains Wnt and other developmental transcriptional networks and suggest that HMGA1 overexpression fosters carcinogenesis and tumor progression through dysregulation of these pathways. Studies are now needed to determine more precisely how HMGA1 modulates chromatin structure to amplify developmental genes and how to disrupt this process in cancer therapy. Cancer Res; 78(8); 1890-7. ©2018 AACR.

HMGA1 Mediated High-Glucose-Induced Vascular Smooth Muscle Cell Proliferation in Diabetes Mellitus: Association Between PI3K/Akt Signaling and HMGA1 Expression

High-mobility group protein A1 (HMGA1), an architectural transcription factor, was found to regulate multiple gene expression in mammals. Recent studies firmly indicate an association between HMGA1 and type 2 diabetes. However, the presence and function of HMGA1 in diabetic vasculopathy has not been substantiated. in this study, we first determined the HMGA1 changes in aorta tissue of diabetic rats. In streptozotocin-induced diabetic rats, a higher level of blood glucose and plasma lipids, an increase of intima-media thickness, and a significant upregulation and accumulation of HMGA1, mainly in the nucleus and around the nuclear membrane of vascular smooth muscle cells (VSMCs), were detected. In vitro, high glucose increased HMGA1 expression and promoted proliferation of VSMCs, which could be blunted by Wortmannin and LY294002, inhibitors of PI3K/Akt pathway, and specificity protein 1 (SP1) siRNA. Moreover, knockdown of HMGA1 could weaken the upregulation of cyclin D1 accompanied by high-glucose-induced HMGA1 in VSMCs. Taken together, these findings demonstrate the vital role of PI3K/Akt-SP1-HMGA1 pathway in high-glucose-induced VSMCs proliferation.

Transcriptional Regulation of Glucose Metabolism: The Emerging Role of the HMGA1 Chromatin Factor

HMGA1 (high mobility group A1) is a nonhistone architectural chromosomal protein that functions mainly as a dynamic regulator of chromatin structure and gene transcription. As such, HMGA1 is involved in a variety of fundamental cellular processes, including gene expression, epigenetic regulation, cell differentiation and proliferation, as well as DNA repair. In the last years, many reports have demonstrated a role of HMGA1 in the transcriptional regulation of several genes implicated in glucose homeostasis. Initially, it was proved that HMGA1 is essential for normal expression of the insulin receptor (INSR), a critical link in insulin action and glucose homeostasis. Later, it was demonstrated that HMGA1 is also a downstream nuclear target of the INSR signaling pathway, representing a novel mediator of insulin action and function at this level. Moreover, other observations have indicated the role of HMGA1 as a positive modulator of the Forkhead box protein O1 (FoxO1), a master regulatory factor for gluconeogenesis and glycogenolysis, as well as a positive regulator of the expression of insulin and of a series of circulating proteins that are involved in glucose counterregulation, such as the insulin growth factor binding protein 1 (IGFBP1), and the retinol binding protein 4 (RBP4). Thus, several lines of evidence underscore the importance of HMGA1 in the regulation of glucose production and disposal. Consistently, lack of HMGA1 causes insulin resistance and diabetes in humans and mice, while variations in the HMGA1 gene are associated with the risk of type 2 diabetes and metabolic syndrome, two highly prevalent diseases that share insulin resistance as a common pathogenetic mechanism. This review intends to give an overview about our current knowledge on the role of HMGA1 in glucose metabolism. Although research in this field is ongoing, many aspects still remain elusive. Future directions to improve our insights into the pathophysiology of glucose homeostasis may include epigenetic studies and the use of "omics" strategies. We believe that a more comprehensive understanding of HMGA1 and its networks may reveal interesting molecular links between glucose metabolism and other biological processes, such as cell proliferation and differentiation.

Role of high mobility group A1 and body mass index in the prognosis of patients with breast cancer

The high mobility group A1 (HMGA1) protein is associated with poor prognosis in patients with a wide range of cancers. However, the affect of HMGA1 on the risk of mortality from breast cancer (BC) has not been fully characterized. In the present retrospective multiple center study, the HMGA1 expression level was determined by performing immunohistochemistry on surgical tissue samples of 273 BC specimens from the Second Affiliated Hospital of Zhejiang University (Zhejiang, China) and 310 BCs from the National Engineering Center for Biochip (Shanghai, China). Kaplan-Meier analysis and Cox proportional hazard model were employed to analyze the survivability. HMGA1 expression was significantly associated with tumor histological degree and body mass index (BMI). However, HMGA1 expression showed no prognostic value in patients with BC. Combined evaluation of HMGA1 expression and high BMI (≥24 kg/m²) predicted worse overall survival of BC. Therefore, HMGA1 and BMI were considered to serve synergistic roles in the development and progression of BC, and combined evaluation of HMGA1 expression and high BMI may be an effective marker in predicting poor prognosis of BC patients.

High mobility group A1 enhances tumorigenicity of human cholangiocarcinoma and confers resistance to therapy

High mobility group A1 (HMGA1) protein has been described to play an important role in numerous types of human carcinoma. By the modulation of several target genes HMGA1 promotes proliferation and epithelial-mesenchymal transition of tumor cells. However, its role in cholangiocarcinoma (CCA) has not been addressed yet. Therefore, we determined HMGA1 mRNA expression in CCA samples in a transcriptome array (n = 104) and a smaller cohort (n = 13) by qRT-PCR. Protein expression was evaluated by immunohistochemistry in a tissue microarray (n = 67). In addition, we analyzed changes in cell proliferation, colony formation, response to gemcitabine treatment, and target gene expression after modulation of HMGA1 expression in CCA cell lines. mRNA levels of HMGA1 were found to be upregulated in 15-62% depending on the cohort analyzed. Immunohistochemistry showed HMGA1 overexpression in 51% of CCA specimens. Integration with clinico-pathological data revealed that high HMGA1 expression was associated with reduced time to recurrence and a positive lymph node status in extrahepatic cholangiocellular carcinoma. In vitro experiments showed that overexpression of HMGA1 in CCA cell lines promoted cell proliferation, whereas its suppression reduced growth rate. HMGA1 further promoted colony formation in an anchorage independent growth and conferred resistance to gemcitabine treatment. Finally, HMGA1 modulated the expression of two genes involved in CCA carcinogenesis, iNOS and ERBB2. In conclusion, our findings indicate that HMGA1 expression is increased in a substantial number of CCA specimens. HMGA1 further promotes CCA tumorigenicity and confers resistance to chemotherapy.

HMGA1 amplifies Wnt signalling and expands the intestinal stem cell compartment and Paneth cell niche

High-mobility group A1 (Hmga1) chromatin remodelling proteins are enriched in intestinal stem cells (ISCs), although their function in this setting was unknown. Prior studies showed that Hmga1 drives hyperproliferation, aberrant crypt formation and polyposis in transgenic mice. Here we demonstrate that Hmga1 amplifies Wnt/β-catenin signalling to enhance self-renewal and expand the ISC compartment. Hmga1 upregulates genes encoding both Wnt agonist receptors and downstream Wnt effectors. Hmga1 also helps to 'build' an ISC niche by expanding the Paneth cell compartment and directly inducing Sox9, which is required for Paneth cell differentiation. In human intestine, HMGA1 and SOX9 are positively correlated, and both become upregulated in colorectal cancer. Our results define a unique role for Hmga1 in intestinal homeostasis by maintaining the stem cell pool and fostering terminal differentiation to establish an epithelial stem cell niche. This work also suggests that deregulated Hmga1 perturbs this equilibrium during intestinal carcinogenesis.

TGF-β1 induces HMGA1 expression: The role of HMGA1 in thyroid cancer proliferation and invasion

The role of transforming growth factor-β1 (TGF-β1) is complicated and plays a different role in the development of cancer. High mobility group A (HMGA1) participates in multiple cellular biology processes, and exerts important roles in the epithelial-mesenchymal transition (EMT). However, the correlation of TGF-β1 and HMGA1 in cancer cells is not yet fully understood. In this study, we determined the effects of TGF-β1 on HMGA1 expression in thyroid cancer cells and examined the role of HMGA1 in thyroid cancer progression. With real-time PCR and immunofluorescence staining, our study demonstrated that TGF-β1 induced the expression of HMGA1 through phosphoinositide 3-kinase (PI3K) and the extracellular signal-related kinase (ERK) signaling in thyroid cancer cells. With luciferase reported assay, the HMGA1 promoter activity was activated by TGF-β1 in the SW579 cells. Furthermore, lentivirus-mediated HMGA1 knockdown inhibits cellular oncogenic properties of thyroid cancer cells. Clinically, tissue microarray revealed that HMGA1 was expressed in thyroid carcinoma more than that in normal thyroid tissues (P<0.001); expression of HMGA1 and MMP-2 was identified to be positively correlated (P=0.017). The present study established the first link between HMGA1 and TGF-β1 in the regulation of thyroid cancer proliferation and invasion, and provided evidence for the pivotal role of HMGA1 in the progression of thyroid cancer, indicating HMGA1 to be potential biological marker for the diagnosis of thyroid cancer.

The High Mobility Group A1 (HMGA1) Transcriptome in Cancer and Development

BACKGROUND & OBJECTIVES

Chromatin structure is the single most important feature that distinguishes a cancer cell from a normal cell histologically. Chromatin remodeling proteins regulate chromatin structure and high mobility group A (HMGA1) proteins are among the most abundant, nonhistone chromatin remodeling proteins found in cancer cells. These proteins include HMGA1a/HMGA1b isoforms, which result from alternatively spliced mRNA. The HMGA1 gene is overexpressed in cancer and high levels portend a poor prognosis in diverse tumors. HMGA1 is also highly expressed during embryogenesis and postnatally in adult stem cells. Overexpression of HMGA1 drives neoplastic transformation in cultured cells, while inhibiting HMGA1 blocks oncogenic and cancer stem cell properties. Hmga1 transgenic mice succumb to aggressive tumors, demonstrating that dysregulated expression of HMGA1 causes cancer in vivo. HMGA1 is also required for reprogramming somatic cells into induced pluripotent stem cells. HMGA1 proteins function as ancillary transcription factors that bend chromatin and recruit other transcription factors to DNA. They induce oncogenic transformation by activating or repressing specific genes involved in this process and an HMGA1 "transcriptome" is emerging. Although prior studies reveal potent oncogenic properties of HMGA1, we are only beginning to understand the molecular mechanisms through which HMGA1 functions. In this review, we summarize the list of putative downstream transcriptional targets regulated by HMGA1. We also briefly discuss studies linking HMGA1 to Alzheimer's disease and type-2 diabetes.

CONCLUSION

Further elucidation of HMGA1 function should lead to novel therapeutic strategies for cancer and possibly for other diseases associated with aberrant HMGA1 expression.

Comparative Toxicogenomic Responses to the Flame Retardant mITP in Developing Zebrafish

Monosubstituted isopropylated triaryl phosphate (mITP) is a major component of Firemaster 550, an additive flame retardant mixture commonly used in polyurethane foams. Developmental toxicity studies in zebrafish established mITP as the most toxic component of FM 550, which causes pericardial edema and heart looping failure. Mechanistic studies showed that mITP is an aryl hydrocarbon receptor (AhR) ligand; however, the cardiotoxic effects of mITP were independent of the AhR. We performed comparative whole genome transcriptomics in wild-type and ahr2^hu3335 zebrafish, which lack functional ahr2, to identify transcriptional signatures causally involved in the mechanism of mITP-induced cardiotoxicity. Regardless of ahr2 status, mITP exposure resulted in decreased expression of transcripts related to the synthesis of all-trans-retinoic acid and a host of Hox genes. Clustered gene ontology enrichment analysis showed unique enrichment in biological processes related to xenobiotic metabolism and response to external stimuli in wild-type samples. Transcript enrichments overlapping both genotypes involved the retinoid metabolic process and sensory/visual perception biological processes. Examination of the gene-gene interaction network of the differentially expressed transcripts in both genetic backgrounds demonstrated a strong AhR interaction network specific to wild-type samples, with overlapping genes regulated by retinoic acid receptors (RARs). A transcriptome analysis of control ahr2-null zebrafish identified potential cross-talk among AhR, Nrf2, and Hif1α. Collectively, we confirmed that mITP is an AhR ligand and present evidence in support of our hypothesis that mITP's developmental cardiotoxic effects are mediated by inhibition at the RAR level.

HMGA1 Expression in Human Hepatocellular Carcinoma Correlates with Poor Prognosis and Promotes Tumor Growth and Migration in in vitro Models

BACKGROUND

HMGA1 is a non-histone nuclear protein that regulates cellular proliferation, invasion and apoptosis and is overexpressed in many carcinomas. In this study we sought to explore the expression of HMGA1 in HCCs and cirrhotic tissues, and its effect in in vitro models.

METHODS

We evaluated HMGA1 expression using gene expression microarrays (59 HCCs, of which 37 were matched with their corresponding cirrhotic tissue and 5 normal liver donors) and tissue microarray (192 HCCs, 108 cirrhotic tissues and 79 normal liver samples). HMGA1 expression was correlated with clinicopathologic features and patient outcome. Four liver cancer cell lines with stable induced or knockdown expression of HMGA1 were characterized using in vitro assays, including proliferation, migration and anchorage-independent growth.

RESULTS

HMGA1 expression increased monotonically from normal liver tissues to cirrhotic tissue to HCC (P<.01) and was associated with Edmondson grade (P<.01). Overall, 51% and 42% of HCCs and cirrhotic tissues expressed HMGA1, respectively. Patients with HMGA1-positive HCCs had earlier disease progression and worse overall survival. Forced expression of HMGA1 in liver cancer models resulted in increased cell growth and migration, and vice versa. Soft agar assay showed that forced expression of HMGA1 led to increased foci formation, suggesting an oncogenic role of HMGA1 in hepatocarcinogenesis.

CONCLUSIONS

HMGA1 is frequently expressed in cirrhotic tissues and HCCs and its expression is associated with high Edmondson grade and worse prognosis in HCC. Our results suggest that HMGA1 may act as oncogenic driver of progression, implicating it in tumor growth and migration potential in liver carcinogenesis.

Fecal Metabolome in Hmga1 Transgenic Mice with Polyposis: Evidence for Potential Screen for Early Detection of Precursor Lesions in Colorectal Cancer

Because colorectal cancer (CRC) remains a leading cause of cancer mortality worldwide, more accessible screening tests are urgently needed to identify early stage lesions. We hypothesized that highly sensitive, metabolic profile analysis of stool samples will identify metabolites associated with early stage lesions and could serve as a noninvasive screening test. We therefore applied traveling wave ion mobility mass spectrometry (TWIMMS) coupled with ultraperformance liquid chromatography (UPLC) to investigate metabolic aberrations in stool samples in a transgenic model of premalignant polyposis aberrantly expressing the gene encoding the high mobility group A (Hmga1) chromatin remodeling protein. Here, we report for the first time that the fecal metabolome of Hmga1 mice is distinct from that of control mice and includes metabolites previously identified in human CRC. Significant alterations were observed in fatty acid metabolites and metabolites associated with bile acids (hypoxanthine xanthine, taurine) in Hmga1 mice compared to controls. Surprisingly, a marked increase in the levels of distinctive short, arginine-enriched, tetra-peptide fragments was observed in the transgenic mice. Together these findings suggest that specific metabolites are associated with Hmga1-induced polyposis and abnormal proliferation in intestinal epithelium. Although further studies are needed, these data provide a compelling rationale to develop fecal metabolomic analysis as a noninvasive screening tool to detect early precursor lesions to CRC in humans.

MicroRNA-214 suppresses growth, migration and invasion through a novel target, high mobility group AT-hook 1, in human cervical and colorectal cancer cells

Background:

MicroRNA-214 (miR-214) has been shown to act as a tumour suppressor in human cervical and colorectal cancer cells. The aim of this study was to experimentally validate high mobility group AT-hook 1 as a novel target for miR-214-mediated suppression of growth and motility.

Methods:

HMGA1 and miR-214 expression levels were estimated in cervical and colorectal clinical specimens using qPCR. HMGA1 3′ untranslated region luciferase assays were performed to validate HMGA1 as a target of miR-214. Effect of altering the expression of miR-214 or HMGA1 on proliferation, migration and invasion of human cervical and colorectal cancer cells was investigated.

Results:

miR-214 expression was poor while that of HMGA1 was high in cervical and colorectal cancer tissues. miR-214-re-expression or HMGA1 downregulation inhibited proliferation, migration and invasion of cancer cells while miR-214 inhibition had opposite effects. miR-214 was demonstrated to bind to the wild-type 3′ untranslated region of HMGA1 but not with its mutant.

Conclusions:

Low expression of miR-214 concurrent with elevated levels of HMGA1 may contribute to cervical and colorectal cancer progression. miR-214-mediated regulation of HMGA1 is a novel mechanism for its tumour-suppressive actions in human cervical and colorectal cancer cells and opens up avenues for novel therapeutic strategies for these two cancers.

Involvement of microRNA-1297, a new regulator of HMGA1, in the regulation of glioma cell growth in vivo and in vitro

MicroRNAs (miRNAs) are a class of versatile gene expression regulators, participating in the regulation of gene expression at the post-transcriptional level in both physiological and pathological conditions. Gliomas are the most common brain malignancy in adults, and deregulation of microRNAs takes part in the gliomagenesis process. Here, we found that the expression of miR-1297 is significantly reduced in both glioma cell lines and clinical glioma tissues. Using the MTT assay, soft agar colony formation assay and xenograft tumor formation assay, we show that miR-1297 is a tumor suppressor microRNA in gliomas. We demonstrate that the high mobility group protein A1 (HMGA1) is the functional target of miR-1297 in glioma cells. HMGA1 significantly promotes the growth of glioma cells both in vitro and in vivo. Together, we unveil a new molecular mechanism in gliomas that may shed new light on understanding this brain malignancy.

The High Mobility Group A1 (HMGA1) gene is highly overexpressed in human uterine serous carcinomas and carcinosarcomas and drives Matrix Metalloproteinase-2 (MMP-2) in a subset of tumors

OBJECTIVES

Although uterine cancer is the fourth most common cause for cancer death in women worldwide, the molecular underpinnings of tumor progression remain poorly understood. The High Mobility Group A1 (HMGA1) gene is overexpressed in aggressive cancers and high levels portend adverse outcomes in diverse tumors. We previously reported that Hmga1a transgenic mice develop uterine tumors with complete penetrance. Because HMGA1 drives tumor progression by inducing MatrixMetalloproteinase (MMP) and other genes involved in invasion, we explored the HMGA1-MMP-2 pathway in uterine cancer.

METHODS

To investigate MMP-2 in uterine tumors driven by HMGA1, we used a genetic approach with mouse models. Next, we assessed HMGA1 and MMP-2 expression in primary human uterine tumors, including low-grade carcinomas (endometrial endometrioid) and more aggressive tumors (endometrial serous carcinomas, uterine carcinosarcomas/malignant mesodermal mixed tumors).

RESULTS

Here, we report for the first time that uterine tumor growth is impaired in Hmga1a transgenic mice crossed on to an Mmp-2 deficient background. In human tumors, we discovered that HMGA1 is highest in aggressive carcinosarcomas and serous carcinomas, with lower levels in the more indolent endometrioid carcinomas. Moreover, HMGA1 and MMP-2 were positively correlated, but only in a subset of carcinosarcomas. HMGA1 also occupies the MMP-2 promoter in human carcinosarcoma cells.

CONCLUSIONS

Together, our studies define a novel HMGA1-MMP-2 pathway involved in a subset of human carcinosarcomas and tumor progression in murine models. Our work also suggests that targeting HMGA1 could be effective adjuvant therapy for more aggressive uterine cancers and provides compelling data for further preclinical studies.

In Pulmonary Arterial Hypertension, Reduced BMPR2 Promotes Endothelial-to-Mesenchymal Transition via HMGA1 and Its Target Slug

BACKGROUND

We previously reported high-throughput RNA sequencing analyses that identified heightened expression of the chromatin architectural factor High Mobility Group AT-hook 1 (HMGA1) in pulmonary arterial endothelial cells (PAECs) from patients who had idiopathic pulmonary arterial hypertension (PAH) in comparison with controls. Because HMGA1 promotes epithelial-to-mesenchymal transition in cancer, we hypothesized that increased HMGA1 could induce transition of PAECs to a smooth muscle (SM)-like mesenchymal phenotype (endothelial-to-mesenchymal transition), explaining both dysregulation of PAEC function and possible cellular contribution to the occlusive remodeling that characterizes advanced idiopathic PAH.

METHODS AND RESULTS

We documented increased HMGA1 in PAECs cultured from idiopathic PAH versus donor control lungs. Confocal microscopy of lung explants localized the increase in HMGA1 consistently to pulmonary arterial endothelium, and identified many cells double-positive for HMGA1 and SM22α in occlusive and plexogenic lesions. Because decreased expression and function of bone morphogenetic protein receptor 2 (BMPR2) is observed in PAH, we reduced BMPR2 by small interfering RNA in control PAECs and documented an increase in HMGA1 protein. Consistent with transition of PAECs by HMGA1, we detected reduced platelet endothelial cell adhesion molecule 1 (CD31) and increased endothelial-to-mesenchymal transition markers, αSM actin, SM22α, calponin, phospho-vimentin, and Slug. The transition was associated with spindle SM-like morphology, and the increase in αSM actin was largely reversed by joint knockdown of BMPR2 and HMGA1 or Slug. Pulmonary endothelial cells from mice with endothelial cell-specific loss of Bmpr2 showed similar gene and protein changes.

CONCLUSIONS

Increased HMGA1 in PAECs resulting from dysfunctional BMPR2 signaling can transition endothelium to SM-like cells associated with PAH.

MiR-26 down-regulates TNF-α/NF-κB signalling and IL-6 expression by silencing HMGA1 and MALT1

MiR-26 has emerged as a key tumour suppressor in various cancers. Accumulating evidence supports that miR-26 regulates inflammation and tumourigenicity largely through down-regulating IL-6 production, but the underlying mechanism remains obscure. Here, combining a transcriptome-wide approach with manipulation of cellular miR-26 levels, we showed that instead of directly targeting IL-6 mRNA for gene silencing, miR-26 diminishes IL-6 transcription activated by TNF-α through silencing NF-κB signalling related factors HMGA1 and MALT1. We demonstrated that miR-26 extensively dampens the induction of many inflammation-related cytokine, chemokine and tissue-remodelling genes that are activated via NF-κB signalling pathway. Knocking down both HMGA1 and MALT1 by RNAi had a silencing effect on NF-κB-responsive genes similar to that caused by miR-26. Moreover, we discovered that poor patient prognosis in human lung adenocarcinoma is associated with low miR-26 and high HMGA1 or MALT1 levels and not with levels of any of them individually. These new findings not only unravel a novel mechanism by which miR-26 dampens IL-6 production transcriptionally but also demonstrate a direct role of miR-26 in down-regulating NF-κB signalling pathway, thereby revealing a more critical and broader role of miR-26 in inflammation and cancer than previously realized.