Overexpression of HMGA2 in bladder cancer and its association with clinicopathologic features and prognosis HMGA2 as a prognostic marker of bladder cancer

HMGA2 regulation by miRNAs in cancer: affecting cancer hallmarks and therapy response

High mobility group A 2 (HMGA2) is a protein that modulates the structure of chromatin in the nucleus. Importantly, aberrant expression of HMGA2 occurs during carcinogenesis, and this protein is an upstream mediator of cancer hallmarks including evasion of apoptosis, proliferation, invasion, metastasis, and therapy resistance. HMGA2 targets critical signaling pathways such as Wnt/β-catenin and mTOR in cancer cells. Therefore, suppression of HMGA2 function notably decreases cancer progression and improves outcome in patients. As HMGA2 is mainly oncogenic, targeting expression by non-coding RNAs (ncRNAs) is crucial to take into consideration since it affects HMGA2 function. MicroRNAs (miRNAs) belong to ncRNAs and are master regulators of vital cell processes, which affect all aspects of cancer hallmarks. Long ncRNAs (lncRNAs) and circular RNAs (circRNAs), other members of ncRNAs, are upstream mediators of miRNAs. The current review intends to discuss the importance of the miRNA/HMGA2 axis in modulation of various types of cancer, and mentions lncRNAs and circRNAs, which regulate this axis as upstream mediators. Finally, we discuss the effect of miRNAs and HMGA2 interactions on the response of cancer cells to therapy. Regarding the critical role of HMGA2 in regulation of critical signaling pathways in cancer cells, and considering the confirmed interaction between HMGA2 and one of the master regulators of cancer, miRNAs, targeting miRNA/HMGA2 axis in cancer therapy is promising and this could be the subject of future clinical trial experiments.

Trojan-horse silk fibroin nanocarriers loaded with a re-call antigen to redirect immunity against cancer

BACKGROUND

The current challenge for immunotherapies is to generate effective antitumor immunity. Since tumor immune escape mechanisms do not impact pre-existing and consolidated immune responses, we tested the hypothesis of redirecting a pregenerated immunity to cancer: to recall a non-tumor antigen response against the tumor, silk fibroin nanoparticles (SFNs) have been selected as 'Trojan-horse' carriers, promoting the antigen uptake by the tumor cells.

METHODS

SFNs have been loaded with either ovalbumin (OVA) or CpG oligonucleotide (CpG) as antigen or adjuvant, respectively. In vitro uptake of SFNs by tumor (B16/F10 melanoma and MB49 bladder cancer) or dendritic cells, as well as the presence of OVA-specific T cells in splenic and tumor-infiltrating lymphocytes, were assessed by cytometric analyses. Proof-of-concept of in vivo efficacy was achieved in an OVA-hyperimmune B16/F10 murine melanoma model: SFNs-OVA or SFNs-CpG were injected, separately or in association, into the subcutaneous peritumoral area. Cancer dimensions/survival time were monitored, while, at the molecular level, system biology approaches based on graph theory and experimental proteomic data were performed.

RESULTS

SFNs were efficiently in vitro uptaken by cancer and dendritic cells. In vivo peritumor administration of SFNs-OVA redirected OVA-specific cytotoxic T cells intratumorally. Proteomics and systems biology showed that peritumoral treatment with either SFNs-OVA or SFNs-CpG dramatically modified tumor microenvironment with respect to the control (CTR), mainly involving functional modules and hubs related to angiogenesis, inflammatory mediators, immune function, T complex and serpins expression, redox homeostasis, and energetic metabolism. Both SFNs-OVA and SFNs-CpG significantly delayed melanoma growth/survival time, and their effect was additive.

CONCLUSIONS

Both SFNs-OVA and SFNs-CpG induce effective anticancer response through complementary mechanisms and show the efficacy of an innovative active immunotherapy approach based on the redirection of pre-existing immunity against cancer cells. This approach could be universally applied for solid cancer treatments if translated into the clinic using re-call antigens of childhood vaccination.

Upregulation of exosomal circPLK1 promotes the development of non-small cell lung cancer through the miR-1294/ high mobility group protein A1 axis

CircRNAs (circular RNAs) have been implicated in the development and progression of a variety of cancers. The molecular pathways underlying the progression of NSCLC (Non-Small Cell Lung Cancer) and the associated regulation of circRNAs in NSCLC remain to be fully elucidated. In this study, we found that circPLK1 expression was upregulated in serum exosomes and tissues from NSCLC patients. The Kaplan–Meier survival analysis revealed that a high expression level of circPLK1 was associated with a poorer prognosis in NSCLC patients. Exosomes extracted from NSCLC serum could promote the replication, migration, and invasion of NSCLC cells and suppress apoptotic cell death. The overexpression of circPLK1 also promotes the malignant phenotype of NSCLC cells. Molecular analyses demonstrated that circPLK1 directly targets miR-1294 and negatively regulates its activity. And circPLK1 overexpression facilitates the progression of NSCLC by negatively regulating miR-1294 level and maintaining a high-level expression of HMGA1 (High Mobility Group Protein A1). Our study suggests that circPLK1 upregulation plays an important role in NSCLC progression by targeting miR-1294/HMGA1 axis. These data provide a theoretical basis for the development of therapeutic strategy targeting exosomal circPLK1 in NSCLC treatment.

HMGA2 as a Critical Regulator in Cancer Development

The high mobility group protein 2 (HMGA2) regulates gene expression by binding to AT-rich regions of DNA. Akin to other DNA architectural proteins, HMGA2 is highly expressed in embryonic stem cells during embryogenesis, while its expression is more limited at later stages of development and in adulthood. Importantly, HMGA2 is re-expressed in nearly all human malignancies, where it promotes tumorigenesis by multiple mechanisms. HMGA2 increases cancer cell proliferation by promoting cell cycle entry and inhibition of apoptosis. In addition, HMGA2 influences different DNA repair mechanisms and promotes epithelial-to-mesenchymal transition by activating signaling via the MAPK/ERK, TGFβ/Smad, PI3K/AKT/mTOR, NFkB, and STAT3 pathways. Moreover, HMGA2 supports a cancer stem cell phenotype and renders cancer cells resistant to chemotherapeutic agents. In this review, we discuss these oncogenic roles of HMGA2 in different types of cancers and propose that HMGA2 may be used for cancer diagnostic, prognostic, and therapeutic purposes.

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.

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.

microRNA-493 inhibits tongue squamous cell carcinoma oncogenicity via directly targeting HMGA2

Backgrounds

microRNA-493-3p (miR-493) has been reported to be critically downregulated in multiple types of human cancer. However, the expression level, biological roles and underlying mechanism of miR‑493 in tongue squamous cell carcinoma (TSCC) remain to be elucidated.

Methods

RT-qPCR was utilized for the determination of miR-493 expression in TSCC tissues and cell lines. The influence of miR-493 overexpression on TSCC cell proliferation, apoptosis, migration, invasion in vitro and tumor growth in vivo were explored via MTT assay, flow cytometry analysis, cell migration and invasion assays, and xenograft tumors in nude mice, respectively. Bioinformatics analysis, luciferase reporter assays, RT-qPCR and Western blotting were performed to clarify the potential mechanisms involved in the action of miR-493 in TSCC cells.

Results

miR-493 was significantly downregulated in TSCC tissues and cell lines. Decreased miR-493 expression was notably correlated with tumor differentiation, depth of invasion and TNM stage. Additionally, patients with TSCC having low miR-493 expression showed lower overall survival rate. Functionally, miR-493 upregulation inhibited TSCC cell proliferation, migration, invasion in vitro; induced cell apoptosis; and decreased the tumor growth in vivo. Bioinformatics analysis followed by luciferase reporter assays also demonstrated that miR-493 directly bound to the 3'-untranslated region of high-mobility group AT-hook 2 (HMGA2) in TSCC cells, and therefore reduced HMGA2 expression at the mRNA and protein level. Furthermore, HMGA2 was overexpressed in TSCC tissues and inversely correlated with miR-493. Moreover, silenced HMGA2 expression simulated the tumor-suppressing roles of miR-493 overexpression on TSCC cells. HMGA2 overexpression eliminated the inhibitory roles of miR-493 overexpression on TSCC cells.

Conclusion

These observations demonstrated that miR-493 is a tumor suppressor inhibited the oncogenicity of TSCC cells by directly targeting HMGA2. These results provide sufficient evidence for the miR-493/HMGA2 axis as a novel therapeutic target for the treatment of patients with TSCC in the future.

Oncological role of HMGA2 (Review)

The high mobility group A2 (HMGA2) protein is a non‑histone architectural transcription factor that modulates the transcription of several genes by binding to AT‑rich sequences in the minor groove of B‑form DNA and alters the chromatin structure. As a result, HMGA2 influences a variety of biological processes, including the cell cycle process, DNA damage repair process, apoptosis, senescence, epithelial‑mesenchymal transition and telomere restoration. In addition, the overexpression of HMGA2 is a feature of malignancy, and its elevated expression in human cancer predicts the efficacy of certain chemotherapeutic agents. Accumulating evidence has suggested that the detection of HMGA2 can be used as a routine procedure in clinical tumour analysis.

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.

Weighted gene co-expression network analysis and prognostic analysis identifies hub genes and the molecular mechanism related to head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a lethal disease with suboptimal survival outcomes. In this study, we aimed to find an independent prognostic factor of head and neck squamous cell carcinoma and investigate its effect on tumor cell proliferation, apoptosis, migration progress and cell cycle phase. Weighted gene co-expression network analysis (WGCNA) is an analysis method for mining module information in chip data through soft threshold. In this article, it was used to divide differential genes into different modules and determined the ten hub genes. Overall survival (OS) and disease-free survival (DFS) analyses as well as univariate and multivariate regression analyses were used to figure out HMGA2 as the independent prognostic factor. RT-qPCR and western blot results revealed the HMGA2 expression levels. Via colony formation, flow cytometry and wound healing assays, we tested the involvement of HMGA2 knockdown in corresponding cancer cell biological behaviors. HMGA2 level was up-regulated in HNSCC tissues and cell lines (SCC-25 and FaDu) in comparison with their normal counterparts. HMGA2 knockdown decreased cancer cell proliferation, promoted cell apoptosis, blocked cell cycle at G0/G1 phase, and inhibited cell migration. We regarded HMGA2 as a potential diagnostic and therapeutic target of HNSCC.

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.

Epigenetic Contribution of High-Mobility Group A Proteins to Stem Cell Properties

High-mobility group A (HMGA) proteins have been examined to understand their participation as structural epigenetic chromatin factors that confer stem-like properties to embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and cancer stem cells (CSCs). The function of HMGA was evaluated in conjunction with that of other epigenetic factors such as histones and microRNAs (miRs), taking into consideration the posttranscriptional modifications (PTMs) of histones (acetylation and methylation) and DNA methylation. HMGA proteins were coordinated or associated with histone and DNA modification and the expression of the factors related to pluripotency. CSCs showed remarkable differences compared with ESCs and iPSCs.

Comprehensive analysis of aberrantly expressed profiles of lncRNAs and miRNAs with associated ceRNA network in muscle-invasive bladder cancer

Although initially thought to be transcriptional noise, long noncoding RNAs (lncRNAs) are gaining increased attention in human cancers as its diversity function. At present, lncRNAs are regarded as the main part of competing endogenous RNA (ceRNA) network due to its regulation on protein-coding gene expression by acting as miRNA sponges. However, functional roles of lncRNA-mediated ceRNAs in muscle-invasive bladder cancer remain unclear. To clarify relevant potential mechanisms, here we comprehensively compared the expression profiles of mRNAs, lncRNAs and miRNAs between 322 muscle-invasive bladder cancer tissues and 19 non-tumor bladder tissues, based on the Cancer Genome Atlas (TCGA). A total of 22 lncRNAs were identified as aberrantly expressed and had correlations with tumorigenesis and/or progression of muscle-invasive bladder cancer (|log2FoldChange| > 1.5, corrected P value < 0.01). 6 out of the 22 dysregulated lncRNAs functioned as prognostic biomarkers for patients with muscle-invasive bladder cancer according to the overall survival analysis (P value < 0.05). Finally, a dysregulated lncRNA-associated ceRNA network was successfully constructed, which inculdes five muscle-invasive bladder cancer-specific lncRNAs, nine miRNAs and 32 mRNAs. In summary, our study identified novel lncRNAs as candidate prognostic biomarkers and potential therapeutic targets for muscle-invasive bladder cancer, based on large-scale sample size. More importantly, the newly identified ceRNA network will be beneficial for improving the understanding of lncRNA-mediated ceRNA regulatory mechanisms in the pathogenesis of muscle-invasive bladder cancer.

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.

microRNA-363-3p inhibits cell growth and invasion of non‑small cell lung cancer by targeting HMGA2

Lung cancer is the second most common cancer and is the leading cause of cancer-related death worldwide. For decades, increasing evidence revealed that microRNAs may contribute to non‑small cell lung cancer (NSCLC) carcinogenesis and progression and could provide novel therapeutic targets for treatments of patients with NSCLC. Accumulated studies indicate that microRNA (miR)‑363‑3p serves important roles in tumorigenesis and tumor development; however, the role of miR‑363‑3p in NSCLC is still unclear. The current study reported that miR‑363‑3p exhibited reduced expression in NSCLC tissues and cell lines. Reduced miR‑363‑3p expression was correlated with tumor node metastasis classification and distant metastasis of NSCLC patients. Notably, miR‑363‑3p re‑expression significantly suppressed cell proliferation and invasion of NSCLC. Furthermore, bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blotting indicated that (high mobility group AT-hook 2) HMGA2 was a direct target gene of miR‑363‑3p. HMGA2 was increased in NSCLC tissues and inversely associated with HMGA2 expression. Moreover, HMGA2 underexpression had similar effects to miR‑363‑3p overexpression in NSCLC cells. Thus, the current study suggested that miR‑363‑3p may act as a tumor suppressor in NSCLC and that the miR‑363‑3p could be investigated as a therapeutic target for the patients with this disease.

Immunohistochemistry Biomarkers in Nonmuscle Invasive Bladder Cancer

Bladder cancer (BCa) is the most frequent urinary tract neoplasm. BCa results in significant mortality when the disease presents as muscle invasive. Around 75% to 80% of patients present with nonmuscle invasive bladder cancer (NMIBC), but recurrence and progression are significant issues, compelling current guidelines to recommend long-term surveillance. There is therefore an urgent and unmet need to identify and validate accurate biomarkers for the detection of disease recurrence to improve quality of life for the patients and reduce costs for health care providers, while maintaining or improving current outcomes. In this review, 38 publications on immunohistochemistry prognostic biomarkers, that were studied may be related in nonmuscle invasive bladder cancer, have been analyzed. The studies were organized according to the evaluated marker and their findings. It was demonstrated that the combination of independent complementary biomarkers could allow a more accurate prognosis than an isolated marker. Biomarkers, including p53, Ki-67, and CK20, with classic and prognostic factors with recurrence and novel markers such as EN2 may provide a more accurate prediction of outcome compared with any single marker, improving risk stratification and clinical management of patients with BCa.

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.

Heat shock protein 90 is involved in the regulation of HMGA2-driven growth and epithelial-to-mesenchymal transition of colorectal cancer cells

High Mobility Group AT-hook 2 (HMGA2) is a nonhistone chromatin-binding protein which acts as a transcriptional regulating factor involved in gene transcription. In particular, overexpression of HMGA2 has been demonstrated to associate with neoplastic transformation and tumor progression in Colorectal Cancer (CRC). Thus, HMGA2 is a potential therapeutic target in cancer therapy. Heat Shock Protein 90 (Hsp90) is a chaperone protein required for the stability and function for a number of proteins that promote the growth, mobility, and survival of cancer cells. Moreover, it has shown strong positive connections were observed between Hsp90 inhibitors and CRC, which indicated their potential for use in CRC treatment by using combination of data mining and experimental designs. However, little is known about the effect of Hsp90 inhibition on HMGA2 protein expression in CRC. In this study, we tested the hypothesis that Hsp90 may regulate HMGA2 expression and investigated the relationship between Hsp90 and HMGA2 signaling. The use of the second-generation Hsp90 inhibitor, NVP-AUY922, considerably knocked down HMGA2 expression, and the effects of Hsp90 and HMGA2 knockdown were similar. In addition, Hsp90 knockdown abrogates colocalization of Hsp90 and HMGA2 in CRC cells. Moreover, the suppression of HMGA2 protein expression in response to NVP-AUY922 treatment resulted in ubiquitination and subsequent proteasome-dependant degradation of HMGA2. Furthermore, RNAi-mediated silencing of HMGA2 reduced the survival of CRC cells and increased the sensitivity of these cells to chemotherapy. Finally, we found that the NVP-AUY922-dependent mitigation of HMGA2 signaling occurred also through indirect reactivation of the tumor suppressor microRNA (miRNA), let-7a, or the inhibition of ERK-regulated HMGA2 involved in regulating the growth of CRC cells. Collectively, our studies identify the crucial role for the Hsp90-HMGA2 interaction in maintaining CRC cell survival and migration. These findings have significant implications for inhibition HMGA2-dependent tumorigenesis by clinically available Hsp90 inhibitors.

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.

The mRNA related ceRNA-ceRNA landscape and significance across 20 major cancer types

Cross-talk between competitive endogenous RNAs (ceRNAs) through shared miRNAs represents a novel layer of gene regulation that plays important roles in the physiology and development of cancers. However, a global view of their system-level properties across various types of cancers is still unknown. Here, we constructed the mRNA related ceRNA–ceRNA interaction landscape across 20 cancer types by systematically analyzing molecular profiles of 5203 tumors and miRNA regulations. Our study highlights the conserved features shared by pan-cancer and higher similarity within similar origin cell type. Moreover, a core ceRNA network was identified. Function analysis identified a common theme of cancer hallmarks, however they exhibit phenotype-specific connectivity patterns. Besides, we found a marked rewiring in the ceRNA program between various cancers, and further revealed conserved and rewired network ceRNA hubs in each cancer, which were tensely competitive interactions to constitute conserved and cancer-specific modules. By providing mechanistic linkage between known cancer miRNAs, their mediated ceRNA–ceRNA interactions, and the associations with known cancer hallmarks, the inferred cancer ceRNA–ceRNA interaction landscape will serve as a powerful public resource for further biological discoveries of tumorigenesis.

miR‑485‑5p inhibits bladder cancer metastasis by targeting HMGA2

MicroRNA (miRNA or miR)‑485 is a functional miRNA which has received much attention in recent years. However, little is known about the expression of miR‑485 or the role it plays in bladder cancer [namely in metastasis and epithelial‑mesenchymal transition (EMT)]. Thus, in the present study, we aimed to detect the expression of miR‑485 in human bladder cancer tissues and bladder cancer cell lines, and to examine the effects of miR‑485‑5p on bladder cancer cell metastasis and EMT. We found that the expression of miR‑485‑5p was downregulated in the human bladder cancer tissues and different bladder cancer cell lines compared with the normal tissues and cell lines, as demonstrated by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). We enforced the expression of miR‑485‑5p in T24 cells and inhibited the expression of miR‑485‑5p in SW780 cells by transfection with miR‑485‑5p mimic or miR‑485‑5p inhibitor, respectively. The ectopic expression of miR‑485‑5p was shown to inhibit cell metastasis and EMT, whereas the inhibition of miR‑485‑5p expression promoted cell metastasis and EMT, as shown by transwell‑matrigel assay, cell adhesion assay and western blot analysis. Furthermore, a luciferase reporter assay revealed that high mobility group AT‑hook 2 (HMGA2) was a direct target of miR‑485‑5p and that the overexpression of HMGA2 reversed the effects of miR‑485‑5p on cell metastasis and EMT. In conclusion and to the very best of our knowledge, the present study, for the first time, identified miR‑485‑5p as a suppressive miRNA in human bladder cancer, and demonstrated that miR‑485‑5p inhibits cell metastasis and EMT at least partly through the suppression of HMGA2 expression.

HMGA2 is associated with epithelial-mesenchymal transition and can predict poor prognosis in nasopharyngeal carcinoma

Objective

High-mobility group protein 2 (HMGA2) and epithelial–mesenchymal transition (EMT)-associated proteins play key roles in cancer progression and metastasis. However, the clinical significance of HMGA2 and its relationship with EMT markers in nasopharyngeal carcinoma (NPC) is unclear. This study aimed to assess the clinicopathological significance and prognostic value of HMGA2, E-cadherin, and vimentin in NPC.

Methods

Using immunohistochemistry, HMGA2, E-cadherin, and vimentin expression levels were evaluated in NPC (n=124) and non-tumoral inflammatory nasopharynx (n=20) tissues. The association of HMGA2 and EMT markers with clinicopathological characteristics and relationships between the protein levels and overall survival were analyzed.

Results

Compared with non-tumorous tissues, HMGA2 and vimentin levels were markedly increased in NPC tissues, whereas decreased E-cadherin levels were observed (P<0.001). Moreover, HMGA2 expression was positively correlated with vimentin levels (r=0.431, P<0.001) and negatively correlated with E-cadherin amounts (r=−0.413, P<0.001) in NPC tissues. The expression of all three proteins correlated significantly with tumor N stage, TNM stage, and 2-year metastasis. Furthermore, significant correlations were found for T stage, N stage, TNM stage, HMGA2, E-cadherin, and vimentin (all P<0.013) with poor prognosis (univariate analysis). However, multivariate analyses showed that only HMGA2 (hazard ratio [HR]: 2.683, 95% confidence interval [CI]: 1.185–6.077, P=0.018) and N stage (HR: 7.892, 95% CI: 2.731–22.807, P<0.001) were independent predictors of poor prognosis.

Conclusion

These results demonstrated that HMGA2, an independent prognostic factor, may promote NPC progression and metastasis, and is significantly associated with EMT proteins. Therefore, HMGA2 may be considered a potential therapeutic target in NPC.

High-mobility group AT-hook 2: an independent marker of poor prognosis in intrahepatic cholangiocarcinoma

High-mobility group AT-hook 2 (HMGA2) regulates cell growth, differentiation, apoptosis, and neoplastic transformation. Previous studies have shown that malignant tumors expressing HMGA2, such as gastric, lung, and colorectal carcinomas, usually have a poor prognosis. HMGA2 expression and its clinical significance in intrahepatic cholangiocarcinomas have not been studied. We identified 55 intrahepatic cholangiocarcinomas resected at our institution from 1994 to 2003. Hematoxylin-eosin-stained slides were reviewed, and histopathologic characteristics were recorded, including mitotic count, tumor grade, vascular and perineural invasion, lymph node metastasis, and margin status. Using immunohistochemical stains, we examined expression of HMGA2, p53, p16, Kit, α-fetoprotein, and Ki-67, and we analyzed the correlation of survival with clinicopathological characteristics and immunohistochemical findings. Positive staining for HMGA2, p53, p16, Kit, α-fetoprotein, and Ki-67 was seen in 18 (33%), 37 (69%), 26 (47%), 21 (38%), 2 (4%), and 34 (63%) tumors, respectively. HMGA2 expression correlated positively with p53 expression (P = .02; ρ = 0.32) and negatively with p16 expression (P = .04; ρ = -0.28). Univariate analysis showed that HMGA2 expression and lymph node metastasis were associated with shorter patient survival and were independent indicators of poor survival (P = .02 and P = .03, respectively). Tumorigenic effects of HMGA2 in intrahepatic cholangiocarcinoma may partly reflect its ability to negatively regulate expression of p16 tumor suppressors and to be associated with p53 abnormalities.

Expression of HMGA2 in bladder cancer and its association with epithelial-to-mesenchymal transition

OBJECTIVES

High mobility group protein2 (HMGA2) and epithelial-to-mesenchymal transition are both related to progress of bladder cancer, however, the relationship between HMGA2, E-cadherin and vimentin in bladder cancer is not yet known. Thus, this study has examined expression of HMGA2, E-cadherin and vimentin in bladder cancer and investigated their relationship.

MATERIALS AND METHODS

The 5637 bladder cancer cell line and SV-HUC-1 normal uroepithelial cells were used to study expression of HMGA2, E-cadherin and vimentin using RT-PCR and western blotting. Paraffin wax-embedded bladder cancer tissues were used to study protein expression using immunohistochemistry and χ(2) analysis and Kendall's correlation were utilized statistical methods.

RESULTS

Overexpression of HMGA2 was associated with down-regulation of E-cadherin and up-regulation of vimentin in the 5637 bladder cancer line. A total of 49 paraffin wax-embedded tissues of transitional cell bladder cancer were used. Positive expression levels of HMGA2 protein and vimentin were 41 and 43% in bladder tissues, respectively. No expression of E-cadherin was found in 43%. Expression of HMGA2, loss of E-cadherin and expression of vimentin are all significantly correlated with bladder cancer grade and stage. Loss of E-cadherin and expression of vimentin both correlated with recurrence of the bladder cancer.

CONCLUSIONS

Expression of HMGA2 was closely associated with occurrence of epithelial-to-mesenchymal transition. Expression of HMGA2, loss of E-cadherin and expression of vimentin may indicate high degree malignancy of bladder cancer. Loss of E-cadherin expression and positive expression of vimentin may predict recurrence of bladder cancer.

Genome-wide association study of primary tooth eruption identifies pleiotropic loci associated with height and craniofacial distances

Twin and family studies indicate that the timing of primary tooth eruption is highly heritable, with estimates typically exceeding 80%. To identify variants involved in primary tooth eruption, we performed a population-based genome-wide association study of 'age at first tooth' and 'number of teeth' using 5998 and 6609 individuals, respectively, from the Avon Longitudinal Study of Parents and Children (ALSPAC) and 5403 individuals from the 1966 Northern Finland Birth Cohort (NFBC1966). We tested 2 446 724 SNPs imputed in both studies. Analyses were controlled for the effect of gestational age, sex and age of measurement. Results from the two studies were combined using fixed effects inverse variance meta-analysis. We identified a total of 15 independent loci, with 10 loci reaching genome-wide significance (P < 5 × 10(-8)) for 'age at first tooth' and 11 loci for 'number of teeth'. Together, these associations explain 6.06% of the variation in 'age of first tooth' and 4.76% of the variation in 'number of teeth'. The identified loci included eight previously unidentified loci, some containing genes known to play a role in tooth and other developmental pathways, including an SNP in the protein-coding region of BMP4 (rs17563, P = 9.080 × 10(-17)). Three of these loci, containing the genes HMGA2, AJUBA and ADK, also showed evidence of association with craniofacial distances, particularly those indexing facial width. Our results suggest that the genome-wide association approach is a powerful strategy for detecting variants involved in tooth eruption, and potentially craniofacial growth and more generally organ development.

miR-154 inhibits EMT by targeting HMGA2 in prostate cancer cells

Epithelial-mesenchymal transition (EMT) is a crucial process that plays an important role in the invasion and metastasis of human cancers. High-mobility group AT-hook 2 (HMGA2) has been found to be involved in the EMT program, with its aberrant expression having been observed in a variety of malignant tumors. However, the mechanisms regulating HMGA2 expression remain incompletely understood. The objective of this study was to investigate whether mir-154 plays a critical role in EMT by regulating HMGA2. The expression levels of HMGA2 were examined in four samples of prostate cancer (PCa) tissue and adjacent non-tumorous tissue by Western blot analysis. The effects of forced expression of miR-154 or HMGA2 knockdown on PCa cells were evaluated by cell migration and invasion assays and Western blot analysis. HMGA2 was upregulated in the PCa tissue samples compared with the adjacent normal ones. Forced expression of miR-154 or HMGA2 knockdown significantly reduced the migratory and invasive capabilities of PCa cells in vitro and inhibited EMT gene expression, increased the levels of E-cadherin, an epithelial marker, and decreased the levels of vimentin, a mesenchymal marker. HMGA2 is a direct target gene of miR-154 by dual-luciferase reporter assay. Our findings suggest that miR-154 plays a role in regulating EMT by targeting HMGA2. Understanding the targets and regulating pathways of miR-154 may provide new insights into the underlying pathogenesis of PCa.

Embryonic stem cell markers

Embryonic stem cell (ESC) markers are molecules specifically expressed in ES cells. Understanding of the functions of these markers is critical for characterization and elucidation for the mechanism of ESC pluripotent maintenance and self-renewal, therefore helping to accelerate the clinical application of ES cells. Unfortunately, different cell types can share single or sometimes multiple markers; thus the main obstacle in the clinical application of ESC is to purify ES cells from other types of cells, especially tumor cells. Currently, the marker-based flow cytometry (FCM) technique and magnetic cell sorting (MACS) are the most effective cell isolating methods, and a detailed maker list will help to initially identify, as well as isolate ESCs using these methods. In the current review, we discuss a wide range of cell surface and generic molecular markers that are indicative of the undifferentiated ESCs. Other types of molecules, such as lectins and peptides, which bind to ESC via affinity and specificity, are also summarized. In addition, we review several markers that overlap with tumor stem cells (TSCs), which suggest that uncertainty still exists regarding the benefits of using these markers alone or in various combinations when identifying and isolating cells.

ShRNA-mediated HMGA2 gene silencing inhibits cell proliferation and promotes apoptosis in human gastric cancer cell line MKN-45

AIM: To investigate the effect of short hairpin RNA (shRNA)-mediated HMGA2 gene silencing on cell growth and apoptosis in human gastric cancer cell line MKN-45.

METHODS: A shRNA eukaryotic expression vector that expresses shRNA targeting the HMGA2 gene was constructed and transfected into MKN-45 cells. HMGA2 protein expression was measured by immunocytochemistry 72 hours after transfection. Cell growth and apoptosis were determined by MTT assay and flow cytometry, respectively.

RESULTS: Compared to the scrambled siRNA group and blank control group, the expression of HMGA2 protein was significantly decreased (171.34 ± 19.61 vs 143.48 ± 19.04, 141.79 ± 18.09, both P < 0.05); cell growth was significantly inhibited (39.32% ± 2.37% vs 5.66% ± 0.63%, P< 0.05); and cell apoptosis was significantly enhanced in the HMGA2-shRNA group (39.67% ± 2.35% vs 4.29% ± 1.33%, 5.05% ± 1.84%, both P < 0.05).

CONCLUSION: ShRNA-mediated HMGA2 gene silencing can effectively induce growth inhibition and apoptosis of MKN-45 cells. HMGA2 might be a potential target for the therapy of gastric cancer.