High mobility group A: A novel biomarker and therapeutic target in pancreatic adenocarcinoma

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.

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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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.

Mandatory role of HMGA1 in human airway epithelial normal differentiation and post-injury regeneration

Due to high levels of expression in aggressive tumors, high mobility group AT-hook 1 (HMGA1) has recently attracted attention as a potential anti-tumor target. However, HMGA1 is also expressed in normal somatic progenitor cells, raising the question: how might systemic anti-HMGA1 therapies affect the structure and function of normal tissue differentiation? In the present study, RNA sequencing data demonstrated HMGA1 is highly expressed in human airway basal stem/progenitor cells (BC), but decreases with BC differentiation in air-liquid interface cultures (ALI). BC collected from nonsmokers, healthy smokers, and smokers with chronic obstructive pulmonary disease (COPD) displayed a range of HMGA1 expression levels. Low initial expression levels of HMGA1 in BC were associated with decreased ability to maintain a differentiated ALI epithelium. HMGA1 down-regulation in BC diminished BC proliferation, suppressed gene expression related to normal proliferation and differentiation, decreased airway epithelial resistance, suppressed junctional and cell polarity gene expression, and delayed wound closure of airway epithelium following injury. Furthermore, silencing of HMGA1 in airway BC in ALI increased the expression of genes associated with airway remodeling in COPD including squamous, epithelial-mesenchymal transition (EMT), and inflammatory genes. Together, the data suggests HMGA1 plays a central role in normal airway differentiation, and thus caution should be used to monitor airway epithelial structure and function in the context of systemic HMGA1-targeted therapies.

Adenovirus-Mediated Delivery of Decoy Hyper Binding Sites Targeting Oncogenic HMGA1 Reduces Pancreatic and Liver Cancer Cell Viability

High mobility group AT-hook 1 (HMGA1) protein is an oncogenic architectural transcription factor that plays an essential role in early development, but it is also implicated in many human cancers. Elevated levels of HMGA1 in cancer cells cause misregulation of gene expression and are associated with increased cancer cell proliferation and increased chemotherapy resistance. We have devised a strategy of using engineered viruses to deliver decoy hyper binding sites for HMGA1 to the nucleus of cancer cells with the goal of sequestering excess HMGA1 at the decoy hyper binding sites due to binding competition. Sequestration of excess HMGA1 at the decoy binding sites is intended to reduce HMGA1 binding at the naturally occurring genomic HMGA1 binding sites, which should result in normalized gene expression and restored sensitivity to chemotherapy. As proof of principle, we engineered the replication defective adenovirus serotype 5 genome to contain hyper binding sites for HMGA1 composed of six copies of an individual HMGA1 binding site, referred to as HMGA-6. A 70%–80% reduction in cell viability and increased sensitivity to gemcitabine was observed in five different pancreatic and liver cancer cell lines 72 hr after infection with replication defective engineered adenovirus serotype 5 virus containing the HMGA-6 decoy hyper binding sites. The decoy hyper binding site strategy should be general for targeting overexpression of any double-stranded DNA-binding oncogenic transcription factor responsible for cancer cell proliferation.

HMGA1 expression levels are elevated in pancreatic intraepithelial neoplasia cells in the Ptf1a-Cre; LSL-KrasG12D transgenic mouse model of pancreatic cancer

BACKGROUND

Pancreatic cancer is currently the third leading cause of cancer deaths in the United States and it is predicted to become the second by the year 2030. High-mobility group A1 protein (HMGA1) is an oncogenic transcription factor, localised and active in cell nuclei, that is linked to tumour progression in many human cancers, including pancreatic cancer. Overexpression of HMGA1 renders cancer cells resistant to chemotherapy. Although the Ptf1a-Cre; LSL-KrasG12D transgenic mouse is perhaps the most widely utilised animal model for human pancreatic cancer, expression levels of HMGA1 in pancreata from this mouse model have not been characterised.

METHODS

Quantitative immunohistochemical analysis was used to determine nuclear HMGA1 levels in pancreatic tissue sections from Ptf1a-Cre; LSL-KrasG12D mice aged 5, 11, and 15 months. The H Score method was used for quantitative analysis.

RESULTS

The HMGA1 levels were significantly elevated in pancreatic intraepithelial neoplasia (PanIN) epithelia compared with untransformed acinar tissues or fibroinflammatory stroma.

CONCLUSIONS

The PanINs have long been regarded as precancerous precursors to pancreatic adenocarcinoma. Significantly elevated HMGA1 levels observed in the nuclei of PanINs in Ptf1a-Cre; LSL-KrasG12D mice validate this animal model for investigating the role that HMGA1 plays in cancer progression and testing therapeutic approaches targeting HMGA1 in human cancers.

Overexpression of HMGA1 correlates with the malignant status and prognosis of breast cancer

High mobility group A1 (HMGA1), as a major member of HMGA family, plays an important part in promotion of cell proliferation and motility, induction of epithelial-mesenchymal transition, and maintenance of stemness, but little is known about the pathological role of HMGA1 in breast cancer patients. The aim of this study was to identify the pathological roles of HMGA1 in breast cancer. In our results, we found that mRNA and protein expression levels of HMGA1 were markedly higher in breast cancer tissues than in normal breast tissues. Using immunohistochemistry, high levels of HMGA1 protein were positively correlated with the status of histological grade (I-II vs. III-IV; P = 0.023), clinical stage (I-II vs. III-IV; P = 0.008), tumor size (T1-T2 vs. T3-T4; P = 0.015), lymph node metastasis (N0-N1 vs. N2-N3; P = 0.002), distant metastasis (M0 vs. M1; P < 0.001), and triple-negative breast cancer (No vs. Yes; P = 0.014) of breast cancer patients. Patients with higher HMGA1 expression had a significantly shorter overall survival time than did patients with low HMGA1 expression. Multivariate analysis indicated that the level of HMGA1 expression was an independent prognostic indicator (P < 0.001) for the survival of patients with breast cancer. In conclusion, HMGA1 plays an important role on breast cancer aggressiveness and prognosis and may act as a promising target for prognostic prediction.

Elevated expression of HMGA1 correlates with the malignant status and prognosis of non-small cell lung cancer

High-mobility group A1 (HMGA1) has been suggested to play a significant role in tumor progression, but little is known about the accurate significance of HMGA1 in non-small cell lung cancer (NSCLC) patients. The aim of this study was to identify the role of HMGA1 in NSCLC. The expression status of HMGA1 was observed initially in NSCLC by Gene Expression Omnibus (GEO). The expression of HMGA1 messenger RNA (mRNA) and protein was examined in NSCLC and adjacent normal lung tissues through real-time PCR and immunohistochemistry. Meanwhile, the relationship of HMGA1 expression levels with clinical features and prognosis of NSCLC patients was analyzed. In our results, HMGA1 was overexpressed in NSCLC tissues compared with adjacent normal lung tissues in microarray data (GSE19804). HMGA1 mRNA and protein expressions were markedly higher in NSCLC tissues than in normal lung tissues (P < 0.001 and P = 0.010, respectively). Using immunohistochemistry, high levels of HMGA1 protein were positively correlated with the status of clinical stage (I-II vs. III-IV, P < 0.001), T classification (T1-T vs. T3-T4, P = 0.003), N classification (N0N1 vs. N2-N3, P < 0.001), M classification (M0 vs. M1, P = 0.002), and differentiated degree (high or middle vs. low or undifferentiated, P = 0.003) in NSCLC. Patients with higher HMGA1 expression had a significantly shorter overall survival time than did patients with low HMGA1 expression. Multivariate analysis indicated that the level of HMGA1 expression was an independent prognostic factor (P < 0.001) for the survival of patients with NSCLC. In conclusion, HMGA1 plays an important role on NSCLC progression and prognosis and may act as a convictive biomarker for prognostic prediction.

Expression of HMGA1 and ezrin in laryngeal squamous cell carcinoma

CONCLUSION

The overexpression of HMGA1 or Ezrin may contribute to the carcinogenesis, development, and metastasis of laryngeal squamous cell carcinoma (LSCC).

OBJECTIVE

To investigate the expression of HMGA1 and Ezrin in LSCC and analyze their clinical significance.

METHODS

The expression of HMGA1 and Ezrin was analyzed by immunohistochemistry (IHC) in 50 cases of LSCC. Thirty cases of laryngeal polyp and 30 cases of atypical hyperplasia of larynx were studied as controls. The expression of HMGA1 and Ezrin was analyzed by real-time PCR and by Western blot in 30 cases of LSCC; samples from adjacent normal epithelial tissues in 30 cases were studied as controls.

RESULTS

(1) IHC revealed that the positive rate of HMGA1 protein was 68.0% (34/50), 53.3% (16/30), and 13. 3% (4/30) in LSCC, atypical hyperplasia of larynx, and laryngeal polyp (p < 0.05), and the positive rate of Ezrin protein was 64.0% (32/50), 50.0% (15/30), and 23.3% (7/30) (p < 0.01), respectively. (2) Real-time PCR demonstrated that the mean relative mRNA expression levels of HMGA1 in LSCC and in normal tissues were 2.41 ± 0.40 and 1.05 ± 0.18, respectively (p < 0.01). The mRNA levels of Ezrin in LSCC and in normal tissues were 1.79 ± 0.27 and 1.04 ± 0.22, respectively (p < 0.05). (3) Western blotting revealed that the mean relative protein expression levels of HMGA1 in LSCC and in normal tissues were 1.73 ± 0.60 and 0.35 ± 0.17, respectively (p < 0.01). The protein levels of Ezrin in LSCC and in normal tissues were 1.82 ± 0.77 and 0.42 ± 0.20, respectively (p < 0.01).

The response of HMGA1 to changes in oxygen availability is evolutionarily conserved

Zebrafish embryos have evolved to cope with hypoxia during development. This includes the ability to completely suspend embryo development for extended periods until normoxia is restored. However, only a limited number of studies have examined the gene regulatory responses of zebrafish embryos to hypoxia. The High Mobility Group A1 protein encoded by the mammalian gene HMGA1 is widely expressed during embryo development but not in adults. Its expression can be induced in adult neurons by hypoxia/oxidative stress and it is commonly reactivated in many types of cancer. We report the identification by phylogenetic and conserved synteny analyses of an HMGA1 orthologue in zebrafish, hmga1 (hmg-i/y) and analysis of sodium azide as a chemical agent for inducing hypoxia-like responses in zebrafish embryos including temporary suspension of development ("suspended animation"). Evidence was only found for the existence of the "a" isoform of HMGA1 in fish. The "b" and "c" isoforms were not detected. We show that zebrafish hmga1 is expressed in a manner similar to in mammals including its induction by hypoxia during hatching stage and in adult zebrafish brain. However, earlier during development, hypoxia causes a decrease in hmga1 transcript levels. By analysis of conservation of the HMGA1a isoform binding site in zebrafish psen2 gene transcripts, we predict that a zebrafish equivalent of the PS2V isoform of human PSEN2 is not formed and we support this by RT-PCR analyses. Thus, analysis of hmga1 function in zebrafish embryogenesis may be valuable for understanding its wider role in vertebrate development, cancer and cellular responses to hypoxia but not for analysis of the action of HMGA1 in PS2V formation.