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

High glucose promotes atherosclerosis by regulating miRNA let7d-5p level

BACKGROUND

MiRNA let7d-5p has been recently reported to be abnormally expressed in diabetes-associated atherosclerosis (AS). However, it still remains unknown how let7d-5p contributes to the process of atherosclerosis.

METHODS

Twenty fresh tissues and a total of 28 wax block specimens from carotid endarterectomy procedures were obtained from the Luoyang Central Hospital affiliated to Zhengzhou University. The expression of let7d-5p was assessed using quantitative RT-PCR (qRT-PCR). A series of in vitro experiments was used to determine the roles of let7d-5p knockdown and overexpression in vascular smooth muscle cells (VSMCs).

RESULTS

We discovered that the carotid plaques from diabetic patients had lower expression levels of miR let7d-5p. In VSMCs, the expression of miRNA let7d-5p was significantly lower in high glucose conditions compared with low glucose situations. The proliferation and migration of VSMCs were also inhibited by the overexpression of let7d-5p, whereas the opposite was true when let7d-5p was inhibited, according to gain and loss of function studies. Mechanically, let7d-5p might activate the GSK3β/β-catenin signaling pathway via binding to the high mobility group AT-Hook 2 (HMGA2) mRNA in VSMCs. Additionally, GLP-1RA liraglutide may prevent the migration and proliferation of VSMCs by raising let7d-5p levels.

CONCLUSIONS

High glucose stimulated the proliferation and migration of VSMCs by regulating the let7d-5p/HMGA2/GSK3β/β-catenin pathway, and liraglutide may slow atherosclerosis by increasing the levels of miR let7d-5p.

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

BACKGROUND/AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

HMGA2-Snai2 axis regulates tumorigenicity and stemness of head and neck squamous cell carcinoma

Cancer stem cells (CSCs) are a tumorigenic cell subpopulation, which contributes to treatment resistance, tumor recurrence, and metastasis. This study aimed to investigate the role and underlying molecular targets of high mobility group AT-hook 2 (HMGA2) in the progression and CSCs regulation of head and neck squamous cell carcinoma (HNSCC). HMGA2 mRNA and protein expression levels were examined in HNSCC specimens and cells by qRT-PCR, Western blot, and immunohistochemistry. The roles of HMGA2 were validated via loss-of-function and exogenous overexpression experiments in vitro and in vivo, and CSCs properties were assessed by tumorsphere formation assay. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays provided further insight into the molecular mechanisms by which HMGA2 regulates stemness. HMGA2 was abnormally overexpressed in HNSCC, and it promoted the expression of the CSCs markers including SOX2, CD133, CD44, ALDH1A1, and Bmi1. HMGA2 was correlated with stemness, malignant progression, and reduced survival in HNSCC. Luciferase reporter assay indicated that Snai2 was a direct downstream target gene of HMGA2. Mechanistically, ChIP-qPCR assay showed that HMGA2 was recruited to three binding sites on the Snai2 promoter, directly facilitating the transcription of Snai2 in HNSCC. Snai2 overexpression reversed the inhibitory effect of HMGA2 interference on the proliferation, invasion, and metastasis of HNSCC and CSC marker expression in vitro and in vivo. HMGA2 promoted the malignant progression of HNSCC and acquired CSCs properties through direct regulation of Snai2, thereby suggesting that targeting the HMGA2-Snai2 axis might be a promising therapeutic strategy for HNSCC.

Molecular Landscape and Prognostic Biomarker Analysis of Advanced Pancreatic Cancer and Predictors of Treatment Efficacy of AG Chemotherapy

Purpose

Although mutational analysis of pancreatic cancer has provided valuable clinical information, it has not significantly changed treatment prospects. The purpose of this study is to further investigate molecular alterations in locally advanced pancreatic cancer and identify predictors of the efficacy of nab-paclitaxel plus gemcitabine (AG) chemotherapy.

Experimental design

Tumor samples from 118 pancreatic cancer patients who received AG chemotherapy as first-line treatment were sequenced and genomic profile was generated. Molecular alterations and the involved signaling pathways were analyzed. Genes with a significant difference in mutation frequency between primary and metastatic tumors were identified, and prognostic-related mutant genes were screened using SPSS version 22.0.

Results

The most common altered genes in the patients were KRAS (94.9%), TP53 (81.4%), CDKN2A (36.4%), and SMAD4 (22.9%). The mutational frequencies of CDKN2B (14.8% vs. 0%, p = 0.001), FAT3 (7.4% vs. 0%, p = 0.041), MTAP (13% vs. 1.6%, p = 0.023), and SMAD4 (31.4% vs. 15.6%, p = 0.049) in metastatic tumors were significantly higher than that in primary tumors. TP35 and KRAS mutations were significantly correlated with objective response rate, while EPHA7, RNF43, and HMGA2 mutations were significantly correlated with disease control rate. Additionally, patients with TGFR2B, FGF23, EPHA7, SMARCA4, CARD11, ADGRA2, CCNE1, and ACVR2A alterations had a worse overall survival. Further, EPHA7, CARD11, NOTCH1, GATA6, ACVR2A, and HMGA2 mutations indicated undesirable progression-free survival.

Conclusions

CDKN2B, FAT3, MTAP, and SMAD4 may be biomarkers that distinguish primary tumors from metastases. EPHA7 mutation may serve as a prognostic biomarker to predict the treatment efficacy of AG chemotherapy in locally advanced pancreatic cancer.

Effects of HMGA2 gene silencing on cell cycle and apoptosis in the metastatic renal carcinoma cell line ACHN

Objective

To explore the role of high mobility group AT-hook 2 (HMGA2) in the regulation of the cell cycle and apoptosis.

Methods

The renal carcinoma cell line ACHN was transiently transfected with small interfering RNA to knock down the expression of the HMGA2 gene. Cell cycle analysis was undertaken using flow cytometry. The mRNA and protein levels of HMGA2, E2F transcription factor 1 (E2F1), cyclin D1, cyclin dependent kinase 6 (CDK6), B-cell lymphoma-2 (Bcl-2), caspase-3 and caspase-9 were analysed using reverse transcription quantitative real-time polymerase chain reaction and Western blot analysis.

Results

The mRNA and protein levels of HMGA2 were significantly higher in renal carcinoma cell lines compared with the human renal proximal tubular epithelial cell line HKC. After HMGA2 gene-specific silencing, more cells entered the G₀/G₁ phase, while fewer cells entered the G₂/M phase; and the cells exhibited early and late apoptosis. HMGA2 gene-specific silencing significantly reduced the mRNA and protein levels of E2F1, cyclin D1, CDK6 and Bcl-2; and increased the mRNA and protein levels of caspase-3 and caspase-9.

Conclusion

The HMGA2 gene may be involved in the tumorigenesis and development of renal cancer, thus inhibiting HMGA2 gene expression might provide a potential therapeutic target in the future.

MicroRNA-let-7 Targets HMGA2 to Regulate the Proliferation, Migration, and Invasion of Colon Cancer Cell HCT116

Objective

To investigate the effect of microRNA-let-7 (miR-let-7) on the proliferation, migration, and invasion of colon cancer cell HCT116 in vitro and its regulatory mechanism on downstream HMGA2.

Methods

It was planned to synthesize miR-let-7 overexpression (mimics) and interference expression (inhibitor) and transiently transfect colon cancer cell HCT116, detect the expression levels of miR-let-7 and HMGA2 in the cells after transfection and the targeted regulation effect of miR-let-7 on HMGA2, then detect the effect of upregulation/downregulation of miR-let-7 on HMGA2, and detect the proliferation, migration, and invasion of HCT116 cells.

Results

The expression of miR-let-7 was downregulated, and the expression of HMGA2 was upregulated in HCT116. The expression of miR-let-7 increased significantly after HCT116 was transfected with miR-let-7 mimics. The expression of miR-let-7 decreased significantly after HCT116 was transfected with miR-let-7 inhibitor. The bioinformatics websites predicted that miR-let-7 has a binding site with HMGA2, and the dual-luciferase reporter gene experiment detected that miR-let-7 has a targeting relationship with HMGA2. The expression of HMGA2 decreased after HCT116 was transfected with miR-let-7 mimics; the expression of HMGA2 increased after HCT116 was transfected with miR-let-7 inhibitor. After upregulating miR-let-7, the proliferation, migration, and invasion ability of HCT116 was weakened. After miR-let-7 was inhibited, the proliferation, migration, and invasion ability of HCT116 was enhanced.

Conclusion

Abnormal expression of miR-let-7 is an important factor affecting the proliferation, migration, and invasion of HCT116 cells, and it can promote or inhibit the biological behavior of cancer cells by targeting the expression of HMGA2. This study provides ideas for the drug development of new gene targets.