Prognostic significance of high mobility group A2 (HMGA2) in pancreatic ductal adenocarcinoma: malignant functions of cytoplasmic HMGA2 expression.

PURPOSE: HMGA2 has frequently been found in benign as well as malignant tumors and a significant association between HMGA2 overexpression and poor survival in different malignancies was described. In pancreatic ductal adenocarcinoma (PDAC), nuclear HMGA2 expression is associated with tumor dedifferentiation and presence of lymph node metastasis. Nevertheless, the impact of HMGA2 occurrence in other cell compartments is unknown. METHODS: Intracellular distribution of HMGA2 was analyzed in PDAC (n = 106) and peritumoral, non-malignant ducts (n = 28) by immunohistochemistry. Findings were correlated with clinico-pathological data. Additionally, intracellular HMGA2 presence was studied by Western blotting of cytoplasmic and nuclear fractions of cultured cells. RESULTS: HMGA2 was found in the cytoplasm and in the nucleus of cultured cells. In human tumor tissue, HMGA2 was also frequently found in the cytoplasm and the nucleus of tumor cells, however, nuclear staining was generally stronger. Direct comparison from tumor tissue with corresponding non-neoplastic peritumoral tissue revealed significantly stronger expression in tumors (p = 0.003). Of note, the nuclear staining was significantly stronger in lymph node metastatic cell nuclei compared to primary tumor cell nuclei (p = 0.049). Interestingly, cytoplasmic staining positively correlated with lymph vessel (p = 0.004) and venous invasion (p = 0.046). CONCLUSION: HMGA2 is a prognostic marker in PDAC. Firstly, we found a positive correlation for cytoplasmic HMGA2 expression with lympho-vascular invasion and, secondly, we found a significantly stronger nuclear expression of HMGA2 in cancer-positive lymph node nuclei compared to primary tumor cell nuclei. So far, the role of cytoplasmic HMGA2 is nearly unknown, however, our data lend support to the hypothesis that cytoplasmic HMGA2 expression is involved in nodal spread.

LncRNA HCP5 knockdown inhibits high glucose-induced excessive proliferation, fibrosis and inflammation of human glomerular mesangial cells by regulating the miR-93-5p/HMGA2 axis.

BACKGROUND: Long non-coding RNAs (lncRNAs) are widely reported to be involved in the development of human diseases. HLA complex P5 (HCP5) deregulation is associated with various diseases. However, the function of HCP5 in diabetic nephropathy (DN) is unclear. METHODS: Human glomerular mesangial cells (HGMCs) were treated with high glucose (HG) to establish DN cell models. The expression of HCP5, miR-93-5p and high mobility group AT-hook 2 (HMGA2) mRNA was detected using quantitative polymerase chain reaction (QPCR). Cell proliferation and cell apoptosis were assessed using cell counting kit-8 (CCK-8) assay and flow cytometry assay, respectively. The expression of apoptosis- and fibrosis-related proteins and HMGA2 protein was quantified by western blot. The release of pro-inflammatory factor was checked using enzyme-linked immunosorbent assay (ELISA). The predicted relationship between miR-93-5p and HCP5 or HMGA2 was verified using dual-luciferase reporter assay, pull-down assay or RNA immunoprecipitation (RIP) assay. RESULTS: The expression of HCP5 and HMGA2 was enhanced, while the expression of miR-93-5p was declined in DN serum samples and HG-treated HGMCs. HCP5 knockdown or miR-93-5p restoration ameliorated HG-induced HGMC proliferation, fibrosis and inflammation. MiR-93-5p was a target of HCP5, and miR-93-5p inhibition reversed the effects caused by HCP5 knockdown. Moreover, HMGA2 was a target of miR-93-5p, and HMGA2 overexpression abolished the effects of miR-93-5p restoration. HCP5 knockdown inhibited the AKT/mTOR signaling pathway. CONCLUSION: HCP5 was implicated in DN progression by modulating the miR-93-5p/HMGA2 axis, which provided new insights into the understanding of DN pathogenesis.

Significance of HMGA2 expression as independent poor prognostic marker in perihilar and distal cholangiocarcinoma resected with curative intent.

BACKGROUND: Extrahepatic cholangiocarcinoma requires invasive surgery and is associated with poor prognosis; thus, a prognostic biomarker is highly needed. Extrahepatic cholangiocarcinoma is sub-classified into two types based on their location, namely perihilar and distal. Perihilar cholangiocarcinoma requires lobectomy as curative surgical resection, whereas the distal requires pancreatoduodenectomy. HMGA2 overexpression is reported to correlate with progression, aggressiveness, dissemination and poor prognosis in several types of cancers. Although its association with extrahepatic cholangiocarcinoma has been reported, none of the previous studies assessed its significance in each subtype. METHODS: We assessed the expression of HMGA2 protein in surgical specimens after curative intent surgery in 80 patients including 41 with perihilar cholangiocarcinoma and 39 with distal cholangiocarcinoma by immunohistochemistry. We then examined its association with clinicopathological findings and patient survival outcomes. RESULTS: We found that HMGA2 was expressed in 51% (21 of 41) of perihilar cholangiocarcinoma and 41% (16 of 39) of distal cholangiocarcinoma samples. In perihilar cholangiocarcinoma, we found significant correlations between expression and vascular invasion and perineural invasion. In distal cholangiocarcinoma, we found that protein levels correlated with tumor grade. Univariate and multivariate analyses demonstrated that HMGA2 expression was an independent poor prognostic factor for patients with both subtypes of disease. CONCLUSIONS: Our results revealed that HMGA2 expression as an independent prognostic marker for both perihilar and distal cholangiocarcinoma that were resected with curative intent.

P300-dependent acetylation of histone H3 is required for epidermal growth factor receptor-mediated high-mobility group protein A2 transcription in hepatocellular carcinoma.

High-mobility group protein A2 (HMGA2) is highly expressed in hepatocellular carcinoma (HCC) cells and contributes to tumor metastasis and poor patient survival. However, the molecular mechanism through which HMGA2 is transcriptionally regulated in HCC cells remains largely unclear. Here, we showed that the expression HMGA2 was upregulated in HCC, and that elevated HMGA2 could promote tumor metastasis. Incubation of HCC cells with epidermal growth factor (EGF) could promote the expression of HMGA2 mRNA and protein. Mechanistic studies suggested that EGF can phosphorylate p300 at Ser1834 residue through the PI3K/Akt signaling pathway in HCC cells. Knockdown of p300 can reverse EGF-induced HMGA2 expression and histone H3-K9 acetylation, whereas a phosphorylation-mimic p300 S1834D mutant can stimulate HMGA2 expression as well as H3-K9 acetylation in HCC cells. Furthermore, we identified that p300-mediated H3-K9 acetylation participates in EGF-induced HMGA2 expression in HCC. In addition, the levels of H3-K9 acetylation positively correlated with the expression levels of HMGA2 in a chemically induced HCC model in rats and human HCC specimens.

HMGA2-mediated tumorigenesis through angiogenesis in leiomyoma.

OBJECTIVE: To study the role of HMGA2 in promoting angiogenesis in uterine leiomyoma (LM). DESIGN: This study involved evaluation of vessel density and angiogenic factors in leiomyomas with HMGA2 overexpression; examining angiogenic factor expression and AKT signaling in myometrial (MM) and leiomyoma cells by introducing HMGA2 overexpression in vitro; and exploring vessel formation induced by HMGA2 overexpression both in vitro and in vivo. SETTING: University research laboratory. PATIENTS: None. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The main outcome measures include vessel density in leiomyomas with HMGA2 (HMGA2-LM) or MED12 (MED12-LM) alteration; angiogenic factor expression in primary leiomyoma and in vitro cell line model; and vessel formation in leiomyoma cells with HMGA2 overexpression in vitro and in vivo. RESULTS: Angiogenic factors and receptors were significantly upregulated at mRNA and protein levels in HMGA2-LM. Specifically, HMGA2-LM exhibited increased expression of VEGFA, EGF, bFGF, TGFα, VEGFR1, and VEGFR2 compared to MED12-LM and myometrium. Overexpression of HMGA2 in MM and LM cell lines resulted in increased secretion of angiogenesis-associated factors. Secreted factors promoted human umbilical vein endothelial cell (HUVEC) migration, tube formation, and wound healing. HMGA2 overexpression upregulated IGF2BP2 and pAKT, and silencing the IGF2BP2 gene reduced pAKT levels and reduced HUVEC migration. Myometrial cells with stable HMGA2 overexpression exhibited increased colony formation and cell growth in vitro and formed xenografts with increased blood vessels. CONCLUSIONS: HMGA2-LM have a high vasculature density, which likely contributes to tumor growth and disease burden of this leiomyoma subtype. HMGA2 plays an important role in angiogenesis and the involvement of IGF2BP2-mediated pAKT activity in angiogenesis, which provides a potential novel target for therapy for this subtype of LM.

High HMGA2 expression without gene rearrangement in meningiomas.

High mobility group AT-hook 2 (HMGA2) is a non-histone transcriptional regulator protein. Aberrant expression of the HMGA2 gene (HMGA2) and structural rearrangement at the chromosomal region 12q14 with HMGA2 involvement have been reported in several mesenchymal tumors. We analyzed truncated and full-length HMGA2 expression in 55 cases of meningioma, the most common brain tumor of mesenchymal origin. Fluorescence in situ hybridization and 3'-rapid amplification of cDNA ends were used to investigate the possibility of gene rearrangements. Moreover, the relationship between HMGA2 expression and clinicopathological features was assessed. Compared with normal brain tissues, 95% of the meningioma tissues exhibited increased HMGA2 expression. In 14 cases, the expression of truncated HMGA2 was more than two-fold higher than that of paired full-length HMGA2. Chromosomal translocation involving the chromosomal region 12q14 was undetectable. No significant correlation was found between the Ki-67 labeling index and HMGA2 expression and between the HMGA2 expression and the clinicopathological features. The majority of the meningioma cases displayed increased HMGA2 expression, which was not attributed to the chromosomal rearrangement at the corresponding region. Similar to that in the other mesenchymal tumors, increased HMGA2 expression was not associated with tumor cell proliferation in meningiomas.

MiR-219-5p inhibits prostate cancer cell growth and metastasis by targeting HMGA2.

OBJECTIVE: To investigate the expression of micro ribonucleic acid (miR)-219-5p in prostate cancer (PCa), its influences on the biological functions of PCa, and its mechanism. PATIENTS AND METHODS: The expression differences of miR-219-5p and high mobility group protein A2 (HMGA2) in 30 pairs of PCa tissues and para-carcinoma tissues were detected via quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), and the difference in miR-219-5p expression in PCa cell lines and normal prostatic epithelial cells was also determined via qRT-PCR. The human PC-3 cells were divided into negative control group and miR-219-5p overexpression group. Methyl thiazolyl tetrazolium (MTT) and colony formation assays were adopted to detect the cell proliferative ability, and flow cytometry was applied to determine the cell apoptosis. The expression of apoptosis-related proteins was measured via Western blotting, and the invasive and migratory abilities of the cells were examined through wound-healing and transwell assays. Bioinformatics prediction software and luciferase reporter assay were employed to verify the targets that might be controlled by miR-219-5p. Rescue experiment was conducted to clarify whether the inhibitory effects of miR-219-5p on the growth and metastasis of PC-3 cells depend on the inhibition of HMGA2. RESULTS: It was shown in qRT-PCR results that the expression level of miR-219-5p was downregulated remarkably in PCa tissues and cell lines, but overexpressed miR-219-5p could repress the proliferation and promote the apoptosis of PC-3 cells notably. The results of wound-healing and transwell assays indicated that overexpressed miR-219-5p was able to suppress the invasion and metastasis of PC-3 cells. According to Western blotting results, overexpressed miR-219-5p could up-regulate the expressions of pro-apoptotic proteins [Bax, cleaved-caspase-3 and cleaved-poly-ADP-ribose-polymerase (PARP)] and reverse the epithelial-mesenchymal transition (EMT) of PCa cells. It was predicted via the bioinformatics software that HMGA2 gene might be a target gene of miR-219-5p. The Dual-Luciferase reporter assay confirmed that there was a direct regulatory relationship between miR-219-5p and HMGA2. The rescue experiment manifested that overexpressed HMGA2 could reverse the inhibition of miR-219-5p on the growth and metastasis of PC-3 cells. CONCLUSIONS: MiR-219-5p suppresses the growth and metastasis abilities of prostate cancer cells by directly repressing the expression of HMGA2.

Cyanidin-3-O-Glucoside Attenuates Lipopolysaccharide-Induced Inflammation in Human Corneal Epithelial Cells by Inducing Let-7b-5p-Mediated HMGA2/PI3K/Akt Pathway.

The bacterial keratitis causes viability loss and apoptosis in the corneal epithelial cells (CECs). The cyanidin-3-O-glucoside (C3G) benefits visual system and also possess anti-bacterial and anti-inflammatory potentials. In the current study, the effects of C3G on human CECs (HCECs) against bacterial lipopolysaccharide (LPS)-induced disorders were assessed, and the mechanism driving the protective effect was explored by focusing on let-7b-5p-mediated HMGA2/PI3K/Akt pathway. The HCECs were incubated LPS of P. aeruginosa to induce inflammation and apoptosis, and then treated with C3G. The changes in cell viability, apoptosis, and inflammation were detected. Moreover, the effects of LPS and C3G on let-7b-5p level and HMGA2/PI3K/Akt pathway activity were also assessed. Thereafter, the HCECs were further transfected with let-7b-5p inhibitor to confirm its role in the vision-protective effects of C3G. The interaction between let-7b-5p and HMGA2 was verified with dual luciferase assay. The LPS treatment suppressed viability and induced apoptosis and inflammation in HCECs, which was associated with the down-regulated let-7b-5p level and up-regulated HMGA2/PI3K/Akt pathway activity. The impairments of LPS on HCECs were attenuated by C3G: the compound increased cell viability and inhibited apoptosis and inflammation. The C3G also induced let-7b-5p level and inactivated HMGA2/PI3K/Akt pathway. However, after the inhibition of let-7b-5p, the protective effects of C3G on HCECs against LPS were blocked. The results of dual luciferase assay showed the direct binding let-7b-5p to the promoter of HMGA2 gene. It was inferred that the C3G could ameliorate the LPS-induced disorders in HCECs. The effect depended on the induced level of let-7b-5p, which then inhibited HMGA2/PI3K/Akt pathway.

Long non-coding RNA-NEAT1, a sponge for miR-98-5p, promotes expression of oncogene HMGA2 in prostate cancer.

Increasing evidence demonstrated that noncoding RNAs (lncRNA, miRNA) play important roles in the cancer development. LncRNA NEAT1 functions as an oncogene in many cancers. However, the roles of NEAT1 in prostate cancer (PCa) remain largely unknown. In the present study, we aim to explore the molecular mechanism of NEAT1 in the development of PCa. We detected the expression levels of NEAT1 in a total of 16 benign prostatic hyperplasia tissues (BPH), 30 matched adjacent healthy control (HC) tissues and 30 PCa tissues, as well as PCa cell lines PC-3, DU-145, LNCaP and normal prostate epithelial cell line RWPE-1. The results showed that NEAT1 was significantly up-regulated in PCa tissues and PCa cell lines. Knockdown of NEAT1 can largely inhibit DU-145 and PC-3 cell growth and invasion. Bioinformatics analysis predicted NEAT1 has the binding site of miR-98-5p which can bind to the 3'UTR of HMGA2. And the expression level of NEAT1 has a positive correlation with HMAG2, while negative correlation with miR-98-5p in PCa cells. In addition, luciference assay and RNA immunoprecipitation (RIP) assay confirmed that NEAT1 can function as a competing endogenous RNA (ceRNA) by sponging miR-98-5p to active HMGA2. Moreover, silencing of HMGA2 can decrease the proliferation ability of PCa cells. Taken together, NEAT1/miR-98-5p/HMGA2 pathway is involved in the development and progression of PCa. NEAT1 could be recommended as a prognostic biomarker and inhibition of NEAT1 expression may be a promising strategy for PCa therapy.

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.

Hydropic leiomyoma: a distinct variant of leiomyoma closely related to HMGA2 overexpression.

Hydropic leiomyoma (HLM) is a variant of uterine leiomyoma with characteristic features of zonal distributions of edema, increased vascularity, and tumor cells arranged in nodules or cords. Diagnostic difficulty and patient management are further complicated by a lack of studies and unknown cause of the disease. To study this tumor's nature, 24 HLM cases were selected for analysis of cytohistologic features, immunohistochemical profile (HMGA2, FH, CD34, pAKT, p16, ER, SMA, and Ki-67), and molecular alterations of HMGA2 by fluorescence in situ hybridization and MED12 mutations. HLM showed large tumor size (average 14.4 cm) and unique histology, characterized by edematous areas of tumor cells with mostly round-oval nuclei, arranged in cords and/or with perinodular growth around vessels, and increased thick-walled vessels (average 17 vessels/10× medium-power field). Immunohistochemistry revealed that 76% (18/24) of HLMs had HMGA2 overexpression, 32% (6/19) of which harbored HMGA2 rearrangement detected by fluorescence in situ hybridization. Thick-walled vessels in HLM were composed of mostly HMGA2-positive tumor cells, and HLM with HMGA2 overexpression also showed CD34-positive tumor vessel-supporting pericytes. In contrast to usual-type leiomyoma with a high frequency of MED12 mutations, no MED12 mutations were found in any HLM. HLM showed increased pAKT activity, indicating a strong contribution of AKT pathway signaling in HLM promoting tumor growth. Our findings suggest that HLM is a distinct variant of uterine smooth muscle tumor likely driven by HMGA2 overexpression.

Expression of PTEN, Androgen Receptor, HER2/neu, Cytokeratin 5/6, Estrogen Receptor-Beta, HMGA2, and PLAG1 in Salivary Duct Carcinoma.

Salivary duct carcinoma (SDC) is an aggressive neoplasm that resembles high-grade invasive ductal carcinoma of the breast. It can develop de novo or from the malignant transformation of pleomorphic adenoma (PA). We performed immunohistochemical stains for phosphatase and tensin homologue [PTEN androgen receptor (AR)], HER2/neu, cytokeratin 5/6, estrogen receptor-beta, high-mobility group AT-hook 2 (HMGA2), and pleomorphic adenoma gene 1 (PLAG1) on tissue microarray samples of 75 SDCs and 31 adenocarcinomas, not otherwise specified (NOS). Our data showed the following in SDC samples: loss of PTEN was found in 17 of 60 (28.3%); AR was expressed in 43 of 62 (69.4%); HER2/neu was overexpressed in 25 of 58 (43.1%); cytokeratin 5/6 was expressed in 14 of 54 (25.9%); estrogen receptor-beta was expressed in 37 of 56 (66.1%); HMGA2 was expressed in 29 of 63 (46.0%); and PLAG1 was expressed in 0 of 62 (0%). In addition, there was no statistically significant difference in the age at onset between patients with HMGA2-positive SDCs (range 32-85 years; mean: 64.3 years; median: 64.5 years) and those with HMGA2-negative SDCs (range 41-79 years; mean: 62.5 years; median: 64.5 years). There was also no statistically significant difference in overall survival between patients with HMGA2-positive and HMGA2-negative SDCs (follow-up period range 3-201 months; mean: 49.8 months; median: 30 months). Among 10 patients with a definite PA component (SDC ex-PA), 6 were positive and 4 were negative for HMGA2. Our data were consistent with previous findings that AR and estrogen receptor-beta are expressed in most SDCs, whereas HER2/neu overexpression and loss of PTEN are expressed in a subset of SDCs. In our cohort of patients, HMGA2 was expressed in approximately half of SDCs. HMGA2 and PTEN are promising therapeutic targets for salivary gland tumors.

The WNT10B Network Is Associated with Survival and Metastases in Chemoresistant Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) commonly develops resistance to chemotherapy, yet markers predictive of chemoresistance in this disease are lacking. Here, we define WNT10B-dependent biomarkers for ß-CATENIN/HMGA2/EZH2 signaling predictive of reduced relapse-free survival. Concordant expression of HMGA2 and EZH2 proteins is observed in MMTV-Wnt10bLacZ transgenic mice during metastasis, and Hmga2 haploinsufficiency decreased EZH2 protein expression, repressing lung metastasis. A novel autoregulatory loop interdependent on HMGA2 and EZH2 expression is essential for ß-CATENIN/TCF-4/LEF-1 transcription. Mechanistically, both HMGA2 and EZH2 displaced Groucho/TLE1 from TCF-4 and served as gatekeepers for K49 acetylation on ß-CATENIN, which is essential for transcription. In addition, we discovered that HMGA2-EZH2 interacts with the PRC2 complex. Absence of HMGA2 or EZH2 expression or chemical inhibition of Wnt signaling in a chemoresistant patient-derived xenograft (PDX) model of TNBC abolished visceral metastasis, repressing AXIN2, MYC, EZH2, and HMGA2 expression in vivo. Combinatorial therapy of a WNT inhibitor with doxorubicin synergistically activated apoptosis in vitro, resensitized PDX-derived cells to doxorubicin, and repressed lung metastasis in vivo. We propose that targeting the WNT10B biomarker network will provide improved outcomes for TNBC. SIGNIFICANCE: These findings reveal targeting the WNT signaling pathway as a potential therapeutic strategy in triple-negative breast cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/5/982/F1.large.jpg.

A 2-Protein Signature Predicting Clinical Outcome in High-Grade Serous Ovarian Cancer.

OBJECTIVE: High-grade serous ovarian cancer (HGSOC) accounts for approximately 70% deaths in ovarian cancer. The overall survival (OS) of HGSOC is poor and still remains a clinical challenge. High-grade serous ovarian cancer can be divided into 4 molecular subtypes. The prognosis of different molecular subtypes is still unclear. We aimed to investigate the prognostic values of immunohistochemistry-based different molecular subtypes in patients with HGSOC. METHODS: We analyzed the protein expression of representative biomarkers (CXCL11, HMGA2, and MUC16) of 3 different molecular subtypes in 110 formalin-fixed, paraffin-embedded HGSOC by tissue microarrays. RESULTS: High CXCL11 expression predicted worse OS, not disease-free survival (DFS; P = 0.028 for OS, P = 0.191 for DFS). High HMGA2 expression predicted worse OS and DFS (P = 0.037 for OS, P = 0.021 for DFS). MUC16 expression was not associated with OS or DFS (P = 0.919 for OS, P = 0.517 for DFS). Multivariate regression analysis showed that CXCL11 combined with HMGA2 signature was an independent predictor for OS and DFS in patients with HGSOC. CONCLUSIONS: CXCL11 combined with HMGA2 signature was a clinically applicable prognostic model that could precisely predict an HGSOC patient's OS and tumor recurrence. This model could serve as an important tool for risk assessment of HGSOC prognosis.

Expression of hsa-let-7b-5p, hsa-let-7f-5p, and hsa-miR-222-3p and their putative targets HMGA2 and CDKN1B in typical and atypical carcinoid tumors of the lung.

Typical and atypical carcinoid tumors belong to the neuroendocrine lung tumors. They have low recurrence and proliferation rate, lymph node, and distant metastases. Nevertheless, these tumors have shown a more aggressive behavior. In the last years, microRNAs were screened as new tumor markers for their potential diagnostic and therapeutic relevance. The expression of hsa-let-7b-5p, hsa-let-7f-5p, hsa-miR-222-3p, and their targets HMGA2 (high-mobility group A2) and CDKN1B (cyclin-dependent kynase inhibitor 1B, p27kip1) was evaluated in this rare small group of patients. We analyzed the clinical data of all typical and atypical carcinoid tumors of patients who underwent surgical operation at Marburg University Hospital (n = 18) from 2000. Quantitative reverse transcription polymerase chain reaction was performed in formalin-fixed paraffin-embedded tumor tissue versus four tumor-free lung tissue samples. HMGA2 was stable or downregulated; only one patient showed a significant overexpression. CDKN1B showed a significant overexpression or a stable level; it was downregulated in two samples only. Hsa-miR-222-3p resulted almost stable or overexpressed except for two samples (significantly downregulated). Hsa-let-7f-5p was stable or overexpressed in the majority of analyzed samples, whereas hsa-let-7b-5p was significantly downregulated. HMGA2 and CDKN1B are differently expressed between atypical and typical carcinoid tumors, thus representing valid biomarkers for the classification of the two tumor groups. Hsa-let-7f-5p and HMGA2 are inversely correlated. Hsa-miR-222-3p does not correlate with its predicted target CDKN1B.

Genomic imbalances are involved in miR-30c and let-7a deregulation in ovarian tumors: implications for HMGA2 expression.

The High-mobility group AT-hook 2 protein (HMGA2) is involved in different processes during tumorigenesis. High expression levels of HMGA2 are found in various types of cancer, with recent studies highlighting the important role of miRNAs in the regulation of HMGA2 expression. We report a study of 155 ovarian tumors (30 sex-cord stromal tumors, 22 borderline tumors, and 103 carcinomas) analyzed for HMGA2 expression as well as the expression of two miRNAs targeting this gene, let-7a and miR-30c. We also evaluated the expression of the fragile histidine triad (FHIT) and lin28 homologues (LIN28A/B) genes which are known to be an enhancer of miR-30c expression and a repressor of let-7a, respectively. HMGA2 was found expressed at high levels in most samples analyzed, with clear cell carcinomas as the only exception. let-7a and miR-30c were highly deregulated in all tumor types. LIN28A and FHIT were found overexpressed in all examined tumor types. The chromosomal imbalances that might lead to loss of the genes expressing let-7a and miR-30c could be evaluated on the basis of previously generated karyotypic and high resolution comparative genomic hybridization (CGH) data on 103 tumors. 76% of the samples with an imbalanced genome had at least one chromosomal aberration leading to a deletion of a miRNA cluster for let-7a and miR-30c. FISH using locus specific probes for these clusters validate the aberrations at the gene level. Our study shows that genomic imbalances are involved in miR-30c and let-7a deregulation. One can reasonably assume that dysregulation of these miRNAs is a cause leading to HMGA2 upregulation in ovarian tumors.

Myolipoma of Soft Tissue: Clinicopathologic Analysis of 34 Cases.

Myolipoma of soft tissue, which was first described by Meis and Enzinger (1991), is a rare benign neoplasm characterized by the admixture of mature adipocytes and well-differentiated smooth muscle cells. Recently, cytogenetic alteration of the HMGA2 gene has been reported in 2 myolipomas. We present the clinicopathologic features of 34 cases of myolipoma of soft tissue, study immunoreactivity for HMGA2, and review the previous literature. In our series, there were 32 women and 2 men, with age at presentation ranging from 35 to 94 years (median, 55 y). The most frequently affected site was retroperitoneum (47%), followed by pelvis (15%), abdominal wall (12%), and intra-abdominal sites (9%). Follow-up information was available for 17 patients (50%), ranging from 1 to 202 months (mean, 41 mo). None has developed local recurrence or metastasis. Grossly, tumors were well circumscribed, and the cut surface showed an admixture of yellowish adipose tissue and tan-whitish nodules. The size ranged from 2.4 to 60 cm (median 10.5 cm). Histologically, the tumors were composed of an intimate admixture of mature fat cells and bland spindle-shaped cells with brightly eosinophilic cytoplasm, arranged in fascicles. Some cases showed the following unusual features focally: hypercellular fascicular pattern (N=2), degenerative nuclear atypia (N=1), round cell morphology (N=1), hemosiderin deposition (N=1), metaplastic cartilage (N=1), metaplastic bone (N=1), and eosinophil infiltrates (N=1). Immunohistochemically, spindle cells showed strong and diffuse positivity for desmin (26/26 cases), SMA (20/21), and ER (13/15). Nuclear positivity for HMGA2 was identified in 15 of 25 cases (60%). MDM2 and CDK4 were usually negative (14/15, 8/9, respectively). In summary, myolipoma of soft tissue is a distinctive benign tumor composed of mature fat cells and smooth muscle cells and arises most commonly in deep-seated locations of middle-aged women. In our study, 60% of cases showed nuclear staining for HMGA2 by immunohistochemistry, which supports the possibility that these tumors harbor aberration of the HMGA2 gene, as seen in lipomas and leiomyomas elsewhere.

The Stem Cell Factor HMGA2 Is Expressed in Non-HPV-Associated Head and Neck Squamous Cell Carcinoma and Predicts Patient Survival of Distinct Subsites.

BACKGROUND: The transcription factor high-mobility AT-hook 2 (HMGA2) is involved in stem cell renewal and is expressed in many tumor tissues. Head and neck squamous cell carcinomas (HNSCC) comprise tumors of the upper aerodigestive tract and are characterized by high recurrence rates that represent a challenge to patient management. The study addresses the potential of HMGA2 as a molecular biomarker for HNSCC patient survival. METHODS: Patients with HNSCC of the larynx, pharynx, tonsils, or oral cavity were recruited in a hospital-based case-control study (n = 202). Quantitative expression of HMGA2 in tumor tissues was measured by RT-PCR. In a 6- to 10-year follow-up, secondary cancers, vital status, and cause of death were ascertained. The HR and 95% confidence intervals (CI) for overall, tumor-specific, and progression-free survival were estimated by Cox proportional hazards with HMGA2 expression level as the independent variable. RESULTS: High HMGA2 expression in tumor tissues of HNSCC patients was significantly correlated with negative HPV status (P = 0.01), and associated with shorter overall survival time. In Cox regression modeling, HMGA2 expression yielded a risk increase for overall and tumor-specific death in subsets of HNSCC patients, that is, laryngeal cancer patients (overall survival: HR = 4.00; 95% CI, 1.18-13.62) and in oral cancer patients (tumor-specific survival: HR = 2.88; 95% CI, 1.06-7.84), but not in patients with pharyngeal and tonsillar HNSCC. CONCLUSIONS: HMGA2 expression is associated with a risk increase for adverse outcomes in patients with HNSCC of the larynx and oral cavity. IMPACT: The understanding of stem cell signaling in HNSCC may offer new strategies for cancer treatment. Cancer Epidemiol Biomarkers Prev; 26(2); 197-205. ©2016 AACR.

The loss of Ezh2 drives the pathogenesis of myelofibrosis and sensitizes tumor-initiating cells to bromodomain inhibition.

EZH2 is a component of polycomb repressive complex 2 (PRC2) and functions as an H3K27 methyltransferase. Loss-of-function mutations in EZH2 are associated with poorer outcomes in patients with myeloproliferative neoplasms (MPNs), particularly those with primary myelofibrosis (MF [PMF]). To determine how EZH2 insufficiency is involved in the pathogenesis of PMF, we generated mice compound for an Ezh2 conditional deletion and activating mutation in JAK2 (JAK2V617F) present in patients with PMF. The deletion of Ezh2 in JAK2(V617F) mice markedly promoted the development of MF, indicating a tumor suppressor function for EZH2 in PMF. The loss of Ezh2 in JAK2(V617F) hematopoietic cells caused significant reductions in H3K27 trimethylation (H3K27me3) levels, resulting in an epigenetic switch to H3K27 acetylation (H3K27ac). These epigenetic switches were closely associated with the activation of PRC2 target genes including Hmga2, an oncogene implicated in the pathogenesis of PMF. The treatment of JAK2(V617F)/Ezh2-null mice with a bromodomain inhibitor significantly attenuated H3K27ac levels at the promoter regions of PRC2 targets and down-regulated their expression, leading to the abrogation of MF-initiating cells. Therefore, an EZH2 insufficiency not only cooperated with active JAK2 to induce MF, but also conferred an oncogenic addiction to the H3K27ac modification in MF-initiating cells that was capable of being restored by bromodomain inhibition.

Developmental regulation of myeloerythroid progenitor function by the Lin28b-let-7-Hmga2 axis.

For appropriate development, tissue and organ system morphogenesis and maturation must occur in synchrony with the overall developmental requirements of the host. Mistiming of such developmental events often results in disease. The hematopoietic system matures from the fetal state, characterized by robust erythrocytic output that supports prenatal growth in the hypoxic intrauterine environment, to the postnatal state wherein granulocytes predominate to provide innate immunity. Regulation of the developmental timing of these myeloerythroid states is not well understood. In this study, we find that expression of the heterochronic factor Lin28b decreases in common myeloid progenitors during hematopoietic maturation to adulthood in mice. This decrease in Lin28b coincides with accumulation of mature let-7 microRNAs, whose biogenesis is regulated by Lin28 proteins. We find that inhibition of let-7 in the adult hematopoietic system recapitulates fetal erythroid-dominant hematopoiesis. Conversely, deletion of Lin28b or ectopic activation of let-7 microRNAs in the fetal state induces a shift toward adult-like myeloid-dominant output. Furthermore, we identify Hmga2 as an effector of this genetic switch. These studies provide the first detailed analysis of the roles of endogenous Lin28b and let-7 in the timing of hematopoietic states during development.