High-mobility-group A2 overexpression provokes a poor prognosis of gastric cancer through the epithelial-mesenchymal transition

Effects of HMGA2 on the biological characteristics and stemness acquisition of gastric cancer cells

BACKGROUND AND STUDY AIMS

The high mobility group A2 (HMGA2), a nonhistone nuclear binding protein, modulates transcription by altering the chromatin architecture of the target gene DNA in its specific AT-hooks region. HMGA2 overexpression has been observed in embryonic tissue and many malignant neoplasms. This study sought to verify whether HMGA2 plays a role in the biological functions of gastric cancer cells, such as cell proliferation, invasiveness, migration, and stem cell acquisition, and to provide some ideas for further research on the metastatic mechanism of gastric cancer.

PATIENTS AND METHODS

HMGA2's effects on the proliferation, invasiveness, and migration capabilities of gastric cancer cells were individually detected by BrdU, Transwell, and wound healing assays. Western blotting and immunofluorescence were used to evaluate whether HMGA2 could promote the acquisition of gastric cancer cells. Biostatistical analyses were performed using SPSS 17.0 for Windows.

RESULTS

HMGA2 expression levels in gastric cancer cell lines were significantly higher than those in human immortalized gastric epithelial cell lines (p < 0.01). Gastric cancer cell proliferation was inhibited when HMGA2 was overexpressed (p < 0.05). The invasiveness and migration capabilities of gastric cancer cells with HMGA2 overexpression were enhanced more than those of the corresponding control groups (p < 0.05). HMGA2 overexpression promotes the stemness acquisition of stem cells from gastric cancer cells.

CONCLUSIONS

This study verified that the HMGA2 structural transcription factor promotes invasiveness, migration, and acquisition of gastric cancer cells. Furthermore, our findings provide significant insight for further research on the metastatic mechanism of gastric cancer.

HMGA2 promotes cancer metastasis by regulating epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) is a complex physiological process that transforms polarized epithelial cells into moving mesenchymal cells. Dysfunction of EMT promotes the invasion and metastasis of cancer. The architectural transcription factor high mobility group AT-hook 2 (HMGA2) is highly overexpressed in various types of cancer (e.g., colorectal cancer, liver cancer, breast cancer, uterine leiomyomas) and significantly correlated with poor survival rates. Evidence indicated that HMGA2 overexpression markedly decreased the expression of epithelial marker E-cadherin (CDH1) and increased that of vimentin (VIM), Snail, N-cadherin (CDH2), and zinc finger E-box binding homeobox 1 (ZEB1) by targeting the transforming growth factor beta/SMAD (TGFβ/SMAD), mitogen-activated protein kinase (MAPK), and WNT/beta-catenin (WNT/β-catenin) signaling pathways. Furthermore, a new class of non-coding RNAs (miRNAs, circular RNAs, and long non-coding RNAs) plays an essential role in the process of HMGA2-induced metastasis and invasion of cancer by accelerating the EMT process. In this review, we discuss alterations in the expression of HMGA2 in various types of cancer. Furthermore, we highlight the role of HMGA2-induced EMT in promoting tumor growth, migration, and invasion. More importantly, we discuss extensively the mechanism through which HMGA2 regulates the EMT process and invasion in most cancers, including signaling pathways and the interacting RNA signaling axis. Thus, the elucidation of molecular mechanisms that underlie the effects of HMGA2 on cancer invasion and patient survival by mediating EMT may offer new therapeutic methods for preventing cancer progression.

Circ_0000658 knockdown inhibits epithelial-mesenchymal transition in bladder cancer via miR-498-induced HMGA2 downregulation

BACKGROUND

Epithelial-mesenchymal transition (EMT) has been associated with the angiogenesis and oncogenic phenotypes of multiple malignant tumors including bladder cancer (BCa). Circular RNAs (circRNAs) are recognized as crucial regulators in the EMT. This study aims to illustrate the possible role of circular RNA_0000658 (circ_0000658) in BCa and the underlying molecular mechanism.

METHODS

The expression of circ_0000658, microRNA (miR)-498, and high mobility group AT-hook 2 (HMGA2) was assessed in cancer and adjacent normal tissue collected from BCa patients and human BCa cell lines (MGH-U3, T24, 5637 and SW780). BCa cells were transduced with a series of overexpression or shRNA plasmids to clarify the function of circ_0000658 and miR-498 on the oncogenic phenotypes and EMT of BCa cells. Further, we established nude mice xenografted with BCa cells to validate the roles of circ_0000658 on tumor growth in vivo.

RESULTS

Circ_0000658 was highly expressed in BCa tissue samples and cell lines, which indicated a poor prognosis of BCa patients. Circ_0000658 competitively bound to miR-498 and thus restricted miR-498 expression. Meanwhile, circ_0000658 weakened the binding of miR-498 to the target gene HMGA2 and upregulated the HMGA2 expression. Circ_0000658 elevation or miR-498 knockdown augmented oncogenic phenotypes and EMT of BCa cells, corresponding to a reduction in the expression of β-catenin and E-cadherin as well as an increase in the expression of N-cadherin, Slug, Snail, ZEB1 and Twist. Inhibition of HMGA2 reversed the effects of circ_0000658 overexpression on tumor growth in vivo.

CONCLUSION

Altogether, our study uncovered the tumor-promoting role of circ_0000658 in BCa via the miR-498/HMGA2 axis.

HMGA1B/2 transcriptionally activated-POU1F1 facilitates gastric carcinoma metastasis via CXCL12/CXCR4 axis-mediated macrophage polarization

Tumor-associated macrophages (TAMs) in the tumor microenvironment contribute to poor prognosis in gastric cancer (GC). However, the underlying mechanism by which TAMs promote GC progression and metastasis remains elusive. Expression of POU1F1 was detected in 60 matched GC-normal tissue pairs using qRT-PCR and immunohistochemistry (IHC) analysis. The correlation between POU1F1 and the clinical-pathological factors of GC patients were further assessed. Cell proliferation was monitored by CCK-8, colony formation, and 5-Ethynyl-2'-deoxyuridine (EdU) incorporation assays. Cell migration and invasion were assessed by transwell assays. The impact on angiogenesis was evaluated by tube formation assay. Xenograft model was generated to investigate the role of POU1F1 on tumor growth and lung metastasis in vivo. GST pull-down and Co-immunoprecipitation (Co-IP) were used to study the interaction between HMGA1B/2 and POU1F1. Chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays were performed to investigate the transcriptional regulation of POU1F1. Flow cytometry was performed to detect the surface expression of macrophage markers. Upregulated POU1F1 observed both in GC tissues and cell lines was positively correlated with poor prognosis. Knockdown of POU1F1 inhibited cell proliferation, migration, invasion, and angiogenesis in vitro, and suppressed tumor growth in vivo. HMGA1B/2 transcriptionally activated-POU1F1. POU1F1 promoted GC progression via regulating macrophage proliferation, migration, polarization, and angiogenesis in a CXCL12/CXCR4-dependent manner. POU1F1 also promoted GC metastasis in lung by modulating macrophage polarization through CXCL12/CXCR4 axis in vivo. HMGA1B/2-upregulated POU1F1 promoted GC metastasis via regulating macrophage polarization in a CXCL12/CXCR4-dependent manner.

The utility of high-mobility group A2 overexpression for predicting the prognosis of gastric cancer patients and its contribution to poor prognosis via chemoresistance and the propensity for the occurrence of carcinomatosis peritonei

BACKGROUND

The aim of this study was to elucidate the correlation of high-mobility group protein A2 overexpression with gastric cancer prognosis and compare its prognostic power with that of pre-existing markers.

METHODS

Malignant tissues from 396 patients with gastric cancer who underwent gastrectomy from 2008 to 2012 were examined. High-mobility group protein A2 expression was assessed by immunohistochemistry and the sensitivity and specificity for predicting disease progression and overall survival of high-mobility group protein A2 and the prognostic biomarkers p53, Ki-67, human epidermal growth factor receptor 2, cyclooxygenase-2, and epidermal growth factor receptor were compared.

RESULTS

A total of 95 samples (24.1%) showed high-mobility group protein A2 overexpression, which was related to advanced stage, undifferentiated histology, and lymphatic and perineural invasion. Additionally, high-mobility group protein A2 overexpression was an independent prognostic factor in multivariate analysis for disease progression and overall survival. Based on Kaplan-Meier survival analysis disease progression and overall survival, the high-mobility group protein A2-overexpressing patients showed worse survival. The recurrence pattern of peritoneal dissemination was more frequently observed in high-mobility group protein A2-positive group. Moreover, chemoresistance was more frequently observed in the high-mobility group protein A2-positive group. High-mobility group protein A2 exhibited a better ability for predicting disease progression and overall survival than other markers, and the prognostic power was enhanced when high-mobility group protein A2 was used with these markers.

CONCLUSION

High-mobility group protein A2 overexpression is associated with chemoresistance and a propensity for carcinomatosis peritonei after surgery in patients with gastric cancer. The power to predict the prognosis of patients with gastric cancer can be enhanced with the use of preexisting biomarkers and high-mobility group protein A2.

High mobility group A protein-2 as a tumor cancer diagnostic and prognostic marker: a systematic review and meta-analysis

High mobility group A protein-2 (HMGA2) is an architectural transcription factor that binds to the A/T-rich DNA minor groove and is responsible for regulating transcriptional activity of multiple genes indirectly through chromatin change and assembling enhanceosome. HMGA2 is overexpressed in multiple tumor types, suggesting its involvement in cancer initiation and progression, thus, making it an ideal candidate for cancer diagnostic and prognostic. We performed a systematic review to examine the role of HMGA2 as a universal tumor cancer diagnostic and prognostic marker. We used Reporting Recommendations for Tumor Marker Prognostic Studies to systematically search OvidMedline, PubMed, and the Cochrane Library for English language studies, published between 1995 and June 2019. Meta-analysis provided pooled risk estimates and their 95% confidence intervals (CIs) for an association between overall survival and recurrence of cancers for studies with available estimates. We identified 42 eligible studies with a total of 5123 tumor samples in 15 types of cancer. The pooled percentage of HMGA2 gene expression in tumor samples was 65.14%. Meta-analysis showed that cancer patients with HMGA2 positive have significantly reduced survival, compared to patients without HMGA2 gene [pooled-hazard ratio (HR) = 1.85, 95% CI 1.48-2.22]. There was a positive association between cancer patients with HMGA2 overexpression and cancer recurrence though this association did not reach significance (pooled-HR = 1.44, 95% CI 0.80-2.07). Overexpression of HMGA2 was found in 15 types of cancer. There was an association between HMGA2 overexpression with reduced survival of cancer patients. HMGA2 is thus considered a promising universal tumor marker for prognostics.

Long non-coding RNA OIP5-AS1 promotes the growth of gastric cancer through the miR-367-3p/HMGA2 axis

Increasing evidence shows that aberrant lncRNAs expression contributes to the progression of gastric cancer (GC). The role of the novel lncRNA OIP5-AS1 and its underlying mechanisms in the growth of GC is largely unknown. Here we demonstrate for the first time that OIP5-AS1 expression was up-regulated in GC tissues and cell lines, which significantly correlated with unfavorable clinical characteristics and shorter survival. The results of in vitro and in vivo gain- and loss-of-function experiments indicate that OIP5-AS1 promoted cell proliferation and colony formation while inhibiting apoptosis of GC cells. OIP5-AS1 functioned as an endogenous sponge for miR-367-3p in GC cells. Restoration of miR-367-3p expression abolished the biological effects of OIP5-AS1 on GC cells. Moreover, we show that HMGA2 was a downstream target of miR-367-3p and mediated the effects of OIP5-AS1 on GC cells. OIP5-AS1 regulated the activities of the PI3K/AKT and Wnt/β-catenin pathways through HMGA2. In conclusion, OIP5-AS1 functions as an oncogenic lncRNA that promotes the progression of GC and may serve as a therapeutic target for managing GC.

Prognostic value of high mobility group protein A2 (HMGA2) over-expression in cancer progression

The high mobility group A2 (HMGA2; also called HMGI-C) gene is an architectural transcription factor that belonging to the high mobility group AT-hook (HMGA) gene family. HMGA2 is aberrantly regulated in several human tumors. Over-expression of HMGA2 is correlated with a higher risk of metastasis and an unfavorable prognosis in patients with cancer. We performed a meta-analysis to determine the clinic-pathological and prognostic value of HMGA2 overexpression in different human tumors. A comprehensive literature search was performed using PubMed, Embase, Cochrane Library, Scopus, MEDLINE, Google Scholar and ISI Web of Science. Hazard ratios (HRs)/odds ratios (ORs) and their 95% confidence intervals (CIs) were used to assess the strength of the association between HMGA2 expression and overall survival (OS)/progression free survival (PFS)/disease free survival (DFS). A total of 5319 patients with 19 different types of cancer from 35 articles were evaluated. Pooled data analysis indicated that increased HMGA2 expression in cancer patients predicted a poor OS (HR = 1.70; 95% CI = 1.6-1.81; P < 0.001; fixed-effect model). In subgroup analyses, high HMGA2 expression was particularly associated with poor OS in individuals with gastrointestinal (GI) cancer (HR = 1.89, 95% CI: 1.83-1.96; fixed-effect model) and HNSCC cancer (HR-1.78, 95%CI: 1.44-2.21; fixed-effect model). Over-expression of HMGA2 was associated with vascular invasion (OR = 0.16, 95% CI = 0.05-0.49; P = 0.001) and lymphatic invasion (OR = 1.89, 95% CI = 1.06-3.38; P = 0.032). Further studies should be conducted to validate the prognostic value of HMGA2 for patients with GI cancers.

HMGA2 and Bach-1 cooperate to promote breast cancer cell malignancy

During breast cancer progression, tumor cells acquire multiple malignant features. The transcription factors and cell cycle regulators high mobility group A2 (HMGA2) and BTB and CNC homology 1 (Bach-1) are overexpressed in several cancers, but the mechanistic understanding of how HMGA2 and Bach-1 promote cancer development has been limited. We found that HMGA2 and Bach-1 are overexpressed in breast cancer tissues and their expression correlates positively in tumors but not in normal tissues. Individual HMGA2 or Bach-1 knockdown downregulates expression of both proteins, suggesting a mutual stabilizing effect between the two proteins. Importantly, combined HMGA2 and Bach-1 knockdown additively decrease cell proliferation, migration, epithelial-to-mesenchymal transition, and colony formation, while promoting apoptotic cell death via upregulation of caspase-3 and caspase-9. First the first time, we show that HMGA2 and Bach-1 overexpression in tumors correlate positively and that the proteins cooperatively suppress a broad range of malignant cellular properties, such as proliferation, migration, clonogenicity, and evasion of apoptotic cell death. Thus, our observations suggest that combined targeting of HMGA2 and Bach1 may be an effective therapeutic strategy to treat breast cancer.

Role of abnormal microRNA expression in Helicobacter pylori associated gastric cancer

Epidemiological studies have shown that Helicobacter pylori (HP) infection is a risk factor for gastric cancer (GC). HP infection may induce the release of pro-inflammatory mediators, and abnormally increase the level of reactive oxygen species (ROS), nitric oxide (NO), and cytokines in mucosal epithelial cells of the stomach. However, the specific mechanism underlying the pathogenesis of HP-associated GC is still poorly understood. Recent studies have revealed that abnormal microRNA expression may affect the proliferation, differentiation, and apoptosis of mucosal epithelial cells of the stomach to further influence GC occurrence, development, and metastasis. Herein, we summarize the role of abnormal microRNAs in the regulation of HP-associated GC progression. Abnormal microRNA expression in HP-positive GC may be a biomarker for GC diagnosis, occurrence, and development as well as its targeted treatment and prognosis.

Multi-platform analysis of methylation-regulated genes in human lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most frequent pathological type of lung cancer that has a poor prognosis and high mortality rate. DNA methylation plays a critical role in various biological processes during development, while dysregulation results in pathological consequences. Thus, this study aimed to identify DNA methylation-regulated genes involved in LUAD occurrence. Initially, 300 downregulated and 168 upregulated mRNA expression levels were identified in two databases: Gene Expression Omnibus (GEO) and The Cancer Genome Atlas. In addition, GEO was utilized to detect 243 DNA hyper-methylated sites. Based on our observations, it was possible to correlate downregulation of mRNA expression and DNA hyper-methylation of six genes (ABCA3, COX7A1, HOXA5, SLIT3, SOX17, and SPARCL1). Functional analysis of the six genes indicated that these genes are predominantly enriched in cancer-related pathways and may promote carcinogenesis by regulating epithelialmesenchymal transition processes. In conclusion, our study identified a panel of DNA methylation-regulated genes involved in LUAD and may serve as potential epigenetic markers for this type of carcinoma.

Prognostic Value of HMGA2 in Human Cancers: A Meta-Analysis Based on Literatures and TCGA Datasets

Background: Emerging evidences have shown that the high-mobility group protein A2 (HMGA2) can aberrantly express in human cancers, and it could be an unfavorable prognostic factor in cancer patients. However, the prognostic value of HMGA2 was still unclear. Therefore, in this study, we explored the potential prognostic value of HMGA2 in human cancers by using meta-analysis based on published literatures and The Cancer Genome Atlas (TCGA) datasets.

Methods: Through searching PubMed, Embase, Web of Science and Cochrane Library databases, we were able to identify the studies evaluating the prognostic value of HMGA2 in cancers. Then, UALCAN and TCGA datasets were used to validate the results of our meta-analysis.

Results: In all, 15 types of cancers were included in this meta-analysis. Pooled results showed that high level of HMGA2 was significantly correlated with poor OS (HR = 1.88, 95% confidence interval (CI) = 1.68-2.11, P < 0.001) and poor DFS (HR = 2.49, 95% CI = 1.44-4.28, P = 0.001) in cancer patients. However, subgroup analyses revealed that the high expressed HMGA2 was associated with poor OS in head and neck cancer, gastric cancer and colorectal cancer, but not esophageal cancer and ovarian cancer. Based on TCGA datasets, we analyzed 9944 patients with 33 types of cancers. Significant association between HMGA2 overexpression and poor OS was found in 14 types of cancers. Taken together, consistent results were observed in clear cell renal cell carcinoma, esophageal adenocarcinoma, head and neck cancer, hepatocellular carcinoma, ovarian carcinoma, and pancreatic ductal adenocarcinoma.

Conclusion: Our meta-analysis showed the significance of HMGA2 and its prognostic value in various cancers. High level of HMGA2 could be associated with poor OS in patients with clear cell renal cell carcinoma, head and neck cancer, hepatocellular carcinoma and pancreatic ductal adenocarcinoma, but not esophageal adenocarcinoma and ovarian carcinoma.

High mobility group protein A2 overexpression indicates poor prognosis for cancer patients: a meta-analysis

Overexpression of the high mobility group protein A2 (HMGA2), an architectural transcription factor, has been linked to poor prognosis in many malignancies, although this remains controversial. Herein, we conducted a meta-analysis to investigate whether HMGA2 has prognostic value, and evaluated the association between HMGA2 and clinicopathologic factors in malignancies. A total of 29 studies involving 4114 patients were included in this meta-analysis. The pooled results demonstrated that elevated HMGA2 predicted a poor overall survival (OS) (hazard ratio [HR] = 1.82; 95% confidence interval [CI] = 1.62-2.05; P < 0.001) and disease-free survival/progression-free survival/recurrence-free survival (HR = 1.94; 95% CI = 1.27-2.98; P = 0.002). Subgroup analysis conducted by study region, sample size, detection method, and analysis method indicated that HMGA2 overexpression correlated with poor OS. Furthermore, HMGA2 overexpression was found to be linked to poor OS in various cancers except ovarian cancer (pooled HR = 1.14; 95% CI = 0.62-2.09; P = 0.673). High HMGA2 expression level also correlated with advanced TNM stage (OR = 2.44; 95% CI =1.87-3.2; P < 0.001), lymphovascular invasion (OR = 2.46, 95% CI = 1.67-3.64; P < 0.001), distant metastasis (OR = 2.66; 95% CI =1.51-4.69; P < 0.001), and lymph node metastasis (OR = 1.83; 95% CI =1.27-2.64; P = 0.001). In conclusion, HMGA2 overexpression indicates a worse prognosis and may serve as a prognostic predictor in cancer patients.

HMGA2 overexpression plays a critical role in the progression of esophageal squamous carcinoma

Esophageal Squamous Cell Carcinoma (ESCC) is the most common esophageal tumor worldwide. However, there is still a lack of deeper knowledge about biological alterations involved in ESCC development. High Mobility Group A (HMGA) protein family has been related with poor outcome and malignant cell transformation in several tumor types. In this way, the aim of this study was to analyze the expression of HMGA1 and HMGA2 expression in ESCC and their role in crucial cellular features. We evaluated HMGA1 and HMGA2 mRNA expression in 52 paired ESCC and normal surrounding tissue samples by qRT-PCR. Here, we show that HMGA2, but not HMGA1, is overexpressed in ESCC samples. This result was further confirmed by the immunohistochemical analysis. Indeed, accordingly to mRNA expression data, HMGA2, but not HMGA1, was overexpressed in approximately 90% of ESCC samples, while it was barely expressed in the respective control. Conversely, HMGA1, but not HMGA2, was overexpressed in esophageal adenocarcinoma samples. Interestingly, HMGA2 abrogation attenuated the malignant phenotype of two ESCC cell lines, suggesting that HMGA2 overexpression is involved in ESCC progression.

Clinicopathological and prognostic significance of HMGA2 overexpression in gastric cancer: a meta-analysis

Background

High mobility group protein A2 (HMGA2) overexpression has been reported to be closely related to tumor progression [1-4] and indicate significantly worse overall survival in gastric cancer [5-8]. However, a final consensus regarding this issue has not yet been reached. Thus, we conducted a meta-analysis to evaluate the association between HMGA2 expression and prognosis of gastric cancer patients.

Methods

The Cochrane Library, Embase, PubMed, Web of Science and China Biology Medicine databases were searched to identify eligible literature published prior to September 2016. In the included studies, the level of HMGA2 amplification was evaluated by immunohistochemistry. We performed a meta-analysis, and pooled relative risk (RRs), hazard ratio (HRs), and 95% confidence intervals (CIs) were analyzed using Review Manager 5.3.

Results

Six studies [5-7, 9-11] involving 712 gastric cancer patients were included and stratified by HMGA2 amplification magnitude. The results of the analysis indicated that higher HMGA2 levels were associated with several clinicopathological parameters and predicted poor prognosis in terms of overall survival (OS).

Conclusions

The results of the present study indicate that higher HMGA2 levels were significantly associated with TNM stage, lymph node status, vascular invasion, and poor OS in patients with gastric cancer. In conclusion, HMGA2 may serve as a promising prognostic biomarker in gastric cancer.

Stroma-regulated HMGA2 is an independent prognostic marker in PDAC and AAC

Background:

The HMGA2 protein has experimentally been linked to EMT and cancer stemness. Recent studies imply that tumour–stroma interactions regulate these features and thereby contribute to tumour aggressiveness.

Methods:

We analysed 253 cases of pancreatic ductal adenocarcinoma (PDAC) and 155 cases of ampullary adenocarcinoma (AAC) for HMGA2 expression by IHC. The data were correlated with stroma abundance and supplemented by experimental studies.

Results:

HMGA2 acts as an independent prognostic marker associated with a significantly shorter overall survival in both tumour types. Overall, HMGA2-positivity was more frequent in patients with PDAC than with AAC. The HMGA2 status in tumour cells significantly correlated with the abundance of PDGFRβ-defined stroma cells. In vivo co-injection of Panc-1 cancer cells with pancreatic stellate cells increased tumour growth in a manner associated with increased HMGA2 expression. Furthermore, in vitro treatment of Panc-1 with conditioned media from PDGF-BB-activated stellate cells increased their ability to form tumour spheroids.

Conclusions:

This study identifies HMGA2 expression in tumour cells as an independent prognostic marker in PDAC and AAC. Correlative data analysis gives novel tissue-based evidence for a heterotypic cross-talk with stroma cells as a possible mechanism for HMGA2 induction, which is further supported by experimental models.

HMGA2-FOXL2 Axis Regulates Metastases and Epithelial-to-Mesenchymal Transition of Chemoresistant Gastric Cancer

Purpose: Chemoresistance is the main cause of treatment failure in cancer and is associated with distant metastases and epithelial-to-mesenchymal transition (EMT). This study was aimed to explore the mechanism of metastases and EMT in chemoresistant gastric cancer.Experimental Design: A key molecular pathway was identified via gene profiling and a bioinformatic analysis in a chemoresistant gastric cancer model. The roles of FOXL2, HMGA2, and ITGA2 were validated via loss-of-function and gain-of-function experiments in vitro and in an orthotopic gastric cancer animal model. The regulation of FOXL2 by HMGA2 was explored via immunoprecipitation and luciferase reporter assays. The expression of these proteins in gastric cancer tissues was examined by IHC.Results: HMGA2 and FOXL2 directly regulated the metastasis and EMT of chemoresistant gastric cancer. The interaction between HMGA2 and pRb facilitated the transactivation of FOXL2 by E2F1, and ITGA2 was the downstream effector of the HMGA2-FOXL2 pathway. HMGA2, FOXL2, and ITGA2 were associated with the TNM classification and staging of gastric cancer and were increased in metastatic lymph nodes and distant metastases. Increased HMGA2, FOXL2, and ITGA2 levels were associated with reduced overall survival periods of patients with gastric cancer.Conclusions: This study demonstrated that the transactivation of FOXL2 driven by interactions between HMGA2 and pRb might exert critical effects on the metastases and EMT of chemoresistant gastric cancer. Blocking the HMGA2-FOXL2-ITGA2 pathway could serve as a new strategy for gastric cancer treatment. Clin Cancer Res; 23(13); 3461-73. ©2017 AACR.

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.

MiR-4500 is epigenetically downregulated in colorectal cancer and functions as a novel tumor suppressor by regulating HMGA2

This study aimed to understand the exact function and potential mechanism of miR-4500 in colorectal cancer (CRC). In this study, the expression of miR-4500 was decreased in both CRC cells and tissues, and downregulated miR-4500 indicated advanced tumor stage and poor survival. By bisulfite sequencing analysis, we found that the CpG island in the promoter region of miR-4500 was hypermethylated in CRC cells and tissues compared with normal control cells and non-tumor tissues, respectively. Functionally, gain- and loss-of-function analyses indicated the tumor suppressor role of miR-4500: it suppressed cell proliferation, cell cycle progression, migration, and invasion. Predictive algorithms and experimental analyses identified HMGA2 as a direct target of miR-4500. Reintroducing HMGA2 impaired the inhibitory effects of miR-4500 on cell growth and motility. Clinically, higher HMGA2 protein expression in CRC tissues was associated with advanced tumor stage and poor survival. An inverse correlation was found between miR-4500 levels and HMGA2 protein expression. Taken together, this study provides the first evidence that miR-4500 functions as a novel tumor suppressor in the miR-4500/HMGA2 axis in colorectal carcinogenesis, and restoring miR-4500 expression might represent a promising therapeutic strategy for CRC.

Let-7c down-regulation in Helicobacter pylori-related gastric carcinogenesis

Aberrant let-7c microRNA (miRNA) expression has been observed in Helicobacter pylori-related gastric cancer (GC) but fragmentary information is available on the let-7c dysregulation occurring with each phenotypic change involved in gastric carcinogenesis. Let-7c expression was assessed (qRT-PCR) in a series of 175 gastric biopsy samples representative of the whole spectrum of phenotypic changes involved in H. pylori-related gastric oncogenesis including: i) normal gastric mucosa, as obtained from dyspeptic controls (40 biopsy samples); ii) non-atrophic gastritis (40 samples); iii) atrophic-metaplastic gastritis (35 samples); iv) intra-epithelial neoplasia (30 samples); v) GC (30 samples). Let-7c expression was also tested in 20 biopsy samples obtained from 10 patients before and after H. pylori eradication therapy (median follow-up: 10 weeks; range: 7-14). The results obtained were further validated by in situ hybridization on multiple tissue specimens obtained from 5 surgically treated H. pylori-related GCs. The study also included 40 oxyntic biopsy samples obtained from serologically/histologically confirmed autoimmune gastritis (AIG: 20 corpus-restricted, non-atrophic; 20 corpus-restricted, atrophic-metaplastic). Let-7c expression dropped from non-atrophic gastritis to atrophic-metaplastic gastritis, intra-epithelial neoplasia, and invasive GC (p<0.001). It rose again significantly following H. pylori eradication (p=0.009). As in the H. pylori model, AIG also featured a significant let-7c down-regulation (p<0.001). The earliest phases of the two pathways to gastric oncogenesis (H. pylori-environmental and autoimmune host-related) are characterized by similar let-7c dysregulations. In H. pylori infection, let-7c down-regulation regresses after the bacterium's eradication, while it progresses significantly with the increasing severity of the histological lesions.

HMGA1/HMGA2 protein expression and prognostic implications in gastric cancer

BACKGROUND

The high mobility group A1 (HMGA1) and high mobility group A2 (HMGA2) proteins are architectural transcription factors that have been implicated in the pathogenesis and progression of multiple malignant tumors, including gastric cancer. The aim of this study was to explore the roles of HMGA1 and HMGA2 in gastric carcinogenesis.

METHODS

The expression of HMGA1 and HMGA2 was examined in 110 gastric adenocarcinomas, 29 gastric adenomas, and 30 normal controls. The results were correlated with the clinicopathological parameters of the tumors and patient outcome.

RESULTS

The levels of HMGA1 and HMGA2 proteins were significantly increased in gastric cancer samples compared with adenoma and normal gastric tissues. High HMGA1 nuclear immunoreactivity was not correlated with clinicopathological features; however, high levels of HMGA2 protein were significantly associated with T stage, N stage, lymphatic invasion, perineural invasion, and TNM stage. Moreover, HMGA2 expression was significantly associated with shorter recurrence free survival. Multivariate analysis showed that HMGA2 expression was an independent prognostic factor for tumor recurrence.

CONCLUSIONS

Our results suggest that HMGA1 and HMGA2 are implicated in gastric carcinogenesis and may play a role in tumor progression towards a more malignant phenotype. The HMGA2 protein may be a useful prognostic marker for predicting tumor recurrence.