High Mobility Group A1 Protein Research Articles

Downregulation of microRNA-196a attenuates ischemic brain injury in rats by directly targeting HMGA1.

Dysfunction of the microRNA (miRNA) network is a major regulator in neurological diseases. However, little is known about the functional significance of miRs in ischemic brain injury. This study was designed to investigate the functional behaviors and regulatory mechanisms of miR-196a in ischemic brain injury. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in rats. The expression levels of miR-196a and HMGA1 were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), Western blotting, and/or immunocytochemistry. The role of miR-196a in cerebral infarction and brain cell apoptosis was determined by infarct volume estimation and Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay, respectively. Bioinformatics software and Luciferase analysis were used to predict and confirm the targets of miR-196a. The results showed that the miR-196a expression was significantly increased in rat brain after MCAO and in cultured neonatal rat cortical neurons after oxygen-glucose deprivation (OGD). Pretreatment with antagomiR-196a by intracerebroventricular markedly reduced the miR-196a mRNA and HMGA1 protein of the brain in rats subjected to MCAO. Notably, the knockdown of miR-196a could protect MCAO rats against cerebral infarction and brain cell apoptosis. In the OGD model, apoptosis and miR-196a expressions were inhibited, while High-Mobility-Group-A1 (HMGA1) levels were increased in cortical neurons in a time-dependent manner. Moreover, HMGA1 was the target gene of miR-196a. MiR-196a overexpression promoted OGD-induced cortical neurons apoptosis possibly through negative regulation of HMGA1. These findings indicated a crucial role of miR-196a in regulating infarct volume and neuronal cell death under cerebral ischemia, thus offering a new target for the development of therapeutic agents against ischemic brain injury.

Retraction: High-Mobility Group A1 Proteins Regulate p53-Mediated Transcription of Bcl-2 Gene.

[This article][1] ([1][2]) has been retracted at the request of the editors. The editors were made aware of concerns regarding potential manipulation of data in the article. An internal review by the editors determined that multiple γ-tubulin Western blot bands appear to be duplicated in Figs. 1A,

Increasing miR-150 and lowering HMGA2 inhibit proliferation and cycle progression of colon cancer in SW480 cells.

High mobility group protein A2 (HMGA2) is a kind of oncogene that regulates cell proliferation and cycle. HMGA2 up-regulation is related to the occurrence of multiple tumors including colorectal cancer. MiR-150 is found down-regulated in colorectal cancer tissue. Bioinformatics analysis shows the complementary targeted relationship between miR-150 and the 3'-UTR of HMGA2. This study explores the role of microRNA-150 (miR-150) in regulating HMGA2 expression, colorectal cancer cell proliferation, and cycle. Colorectal cancer patients were enrolled to collect cancer and para-carcinoma tissues. MiR-150 and HMGA2 expressions were tested in tissue. MiR-150, HMGA2, and Cyclin A levels in colorectal cancer cell line SW480, and normal colorectal epithelial cell line FHC were compared. The targeted relationship between miR-150 and the 3'-UTR of HMGA2 was evaluated by dual luciferase reporter gene assay. SW480 cells were divided into five groups, including miR-control, miR-150 mimic, small interfere normal control (si-NC), si-HMGA2, and miR-150 mimic + si-HMGA2. Cell cycle was determined by using flow cytometry. The cell proliferation was detected by using the cell counting kit 8 (CCK-8) test. HMGA2 expression was significantly increased, while miR-150 levels were significantly declined in colorectal cancer tissue compared with that in para-carcinoma tissue (p<0.05). HMGA2 and Cyclin A levels were higher significantly, whereas miR-150 expression was lower significantly in SW480 cells compared to that in FHC cells (p<0.05). MiR-150 targeted band to the 3'-UTR of HMGA. MiR-150 mimic and/or si-HMGA2 significantly reduced HMGA2 and Cyclin A expressions, blocked cell cycle in the G0/G1 phase, and attenuated cell proliferation. We observed that miR-150 down-regulated Cyclin A expression to block colorectal cancer cell cycle and inhibit proliferation through targeted inhibiting HMGA2.

Nanoparticle‐mediated HMGA1 Silencing Promotes Lymphocyte Infiltration and Boosts Checkpoint Blockade Immunotherapy for Cancer

AbstractFor most cancer types, only a minority of cancer patients respond to checkpoint inhibition therapy. T lymphocyte infiltration is critically important for checkpoint blockade immunotherapy. High expression of high mobility group protein A1 (HMGA1) is observed in rapidly proliferating neoplastic cells, and is reported to contribute to the immunosuppressive microenvironment in the tumor. Herein, whether the silencing of HMGA1 using a nanoparticle (NP) approach could promote T lymphocyte infiltration into the tumor, and sensitize tumors to checkpoint inhibitor therapy in several orthotopic murine cancer models, which has high levels of HMGA1 but little T lymphocyte infiltration, is investigated. Selectively silencing HMGA1 using a lipid‐protamine‐hyaluronic acid‐siHMGA1 (LPH‐siHMGA1) NP system greatly enhances the lymphocyte infiltration in the tumor. Furthermore, the combination of LPH‐siHMGA1 and a locally expressed PD‐L1 inhibitor system, a lipid‐protamine‐DNA NP loaded with plasmid encoding the PD‐L1 trap fusion protein, significantly inhibits the tumor growth and prolonged survival. LPH‐siHMGA1 also decreased the content of stem cells in the tumor. These findings highlight the potential of targeting HMGA1, especially using a nano approach, in the combination with cancer immunotherapy, and provide a strategy for broadening the application and enhancing the efficacy of checkpoint inhibitors.

HMGA2 Modulates the TGFβ/Smad, TGFβ/ERK and Notch Signaling Pathways in Human Lens Epithelial-Mesenchymal Transition.

Multiple signaling pathways coordinately promote epithelial-mesenchymal transition (EMT) in lens epithelial cells (LECs), where transforming growth factor beta (TGFβ)-mediated signaling plays a central role. But the mechanism of crosstalk among these pathways remains obscure. The objective of this study is to investigate the regulatory effect of the high mobility group protein A2 (HMGA2) on the signaling pathways in lens fibrosis. The human anterior capsulorhexis specimens were collected. The human SRA01/04 LEC line was cultured and treated with recombinant human TGFβ2 (5ng/ml). For inhibition of signaling pathways, a selective inhibitor SB431542, U0126 or DAPT was added to LECs respectively. The specific small interfering RNA (siRNA) were transfected to LECs for gene silence. The mRNAs expressions were measured by realtime PCR and the proteins expressions were determined by western blot and immunofluorescent staining. HMGA2 and EMT markers α-smooth muscle actin (SMA), fibronectin (FN) and collagen type I (Col I) were overexpressed in human ASC specimens and TGFβ2 stimulated EMT in LECs. While blockage of EMT by a selective inhibitor of TGFβ/Smad, TGFβ/extracellular signal-regulated kinase (ERK) or Notch signaling pathway could significantly inhibited HMGA2 protein expression. And silence of HMGA2 by siRNA could significantly inhibit TGFβ2 induced expression of EMT markers including FN, Col I, collagen type IV (Col IV), key transcription factors Snail and Slug, and remarkably upregulate the epithelial markers E-cadherin and tight junction protein (ZO-1). In addition, silence of HMGA2 gene could abrogate TGFβ2 induced phosphorylation of Smad2, Smad3 as well as ERK1/2. Blockage of HMGA2 could also inhibit the upregulation of Jagged1, Notch2, and Notch3 induced by TGFβ2. This study indicated that HMGA2 functions as a shared effector in TGFβ2- induced lens fibrosis, modulating the signaling network necessary for EMT in a positive feedback loop.

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 A2 (HMGA2) deficiency in pigs leads to dwarfism, abnormal fetal resource allocation, and cryptorchidism

Expression of HMGA2 is strongly associated with body size and growth in mice and humans. In mice, inactivation of one or both alleles of Hmga2 results in body-size reductions of 20% and 60%, respectively. In humans, microdeletions involving the HMGA2 locus result in short stature, suggesting the function of the HMGA2 protein is conserved among mammals. To test this hypothesis, we generated HMGA2-deficient pigs via gene editing and somatic cell nuclear transfer (SCNT). Examination of growth parameters revealed that HMGA2-/+ male and female pigs were on average 20% lighter and smaller than HMGA2+/+ matched controls (P < 0.05). HMGA2-/- boars showed significant size reduction ranging from 35 to 85% of controls depending on age (P < 0.05), and organ weights were also affected (P < 0.05). HMGA2-/+ gilts and boars exhibited normal reproductive development and fertility, while HMGA2-/- boars were sterile due to undescended testes (cryptorchidism). Crossbreeding HMGA2-/+ boars and gilts produced litters lacking the HMGA2-/- genotype. However, analysis of day (D) D40 and D78 pregnancies indicated that HMGA2-/- fetuses were present at the expected Mendelian ratio, but placental abnormalities were seen in the D78 HMGA2-/- concepti. Additionally, HMGA2-/- embryos generated by gene editing and SCNT produced multiple pregnancies and viable offspring, indicating that lack of HMGA2 is not lethal per se. Overall, our results show that the effect of HMGA2 with respect to growth regulation is highly conserved among mammals and opens up the possibility of regulating body and organ size in a variety of mammalian species including food and companion animals.

HMGA1 Mediated High-Glucose-Induced Vascular Smooth Muscle Cell Proliferation in Diabetes Mellitus: Association Between PI3K/Akt Signaling and HMGA1 Expression.

High-mobility group protein A1 (HMGA1), an architectural transcription factor, was found to regulate multiple gene expression in mammals. Recent studies firmly indicate an association between HMGA1 and type 2 diabetes. However, the presence and function of HMGA1 in diabetic vasculopathy has not been substantiated. in this study, we first determined the HMGA1 changes in aorta tissue of diabetic rats. In streptozotocin-induced diabetic rats, a higher level of blood glucose and plasma lipids, an increase of intima-media thickness, and a significant upregulation and accumulation of HMGA1, mainly in the nucleus and around the nuclear membrane of vascular smooth muscle cells (VSMCs), were detected. In vitro, high glucose increased HMGA1 expression and promoted proliferation of VSMCs, which could be blunted by Wortmannin and LY294002, inhibitors of PI3K/Akt pathway, and specificity protein 1 (SP1) siRNA. Moreover, knockdown of HMGA1 could weaken the upregulation of cyclin D1 accompanied by high-glucose-induced HMGA1 in VSMCs. Taken together, these findings demonstrate the vital role of PI3K/Akt-SP1-HMGA1 pathway in high-glucose-induced VSMCs proliferation.

Identification of key microRNAs, transcription factors and genes associated with congenital obstructive nephropathy in a mouse model of megabladder

ObjectiveThe present study aimed to investigate the molecular mechanism underlying congenital obstructive nephropathy (CON). MethodsThe microarray dataset GSE70879 was downloaded from the Gene Expression Omnibus, including 3 kidney samples of megabladder mice and 4 control kidneys. Using this dataset, differentially expressed miRNAs (DEMs) were identified between the kidney samples from megabladder mice and controls, followed by identification of the target genes for these DEMs and construction of a DEM and target gene interaction network. Additionally, the target genes were subjected to Gene Ontology and pathway enrichment analyses, and were used for construction of a protein-protein interaction (PPI) network. Finally, regulatory networks were constructed to analyze transcription factors for the key miRNAs. ResultsFrom 17 DEMs identified between kidney samples of megabladder mice and controls, 3 key miRNAs were screened, including mmu-miR-150-5p, mmu-miR-374b-5p and mmu-miR-126a-5p. The regulatory networks identified vascular endothelial growth factor A (Vegfa) as the common target gene of mmu-miR-150-5p and five transcription factors, including nuclear receptor subfamily 4, group A, member 2 (Nr4a2), Jun dimerisation protein 2 (Jdp2), Kruppel-like factor 6 (Klf6), Neurexophilin-3 (Nxph3) and RNA binding motif protein 17 (Rbm17). The gene encoding phosphatase and tensin homolog (Pten) was found to be co-regulated by mmu-miR-374b-5p and high mobility group protein A1 (Hmga1), whereas the kirsten rat sarcoma viral oncogene (Kras) was identified as a common target gene of mmu-miR-126a-5p and paired box 6 (Pax6). ConclusionsIn summary, the above-listed key miRNAs, transcription factors and key genes may be involved in the development of CON.

Increased high mobility group A 2 expression promotes transition of cervical intraepithelial neoplasm into cervical cancer.

Integration of the high risk human papillomavirus (HR-HPV) genome into host chromatin is an important step in cervical carcinogenesis. We identified HR-HPV integration sites within the human genome through detection of integrated papillomavirus sequences-PCR and assessed the role of high mobility group A 2 (HMGA2) in cervical carcinogenesis in clinical samples and cell lines. HPV integration sites were analyzed in 40 cervical cancer samples, while copy number variation and protein expression were assessed in 19 normal cervixes, 49 cervical intraepithelial neoplasia (CIN), and 52 cervical cancer samples. Overall, 25 HR-HPV integrating loci were detected in 24 cervical samples; HMGA2 was the only recurring integration site. Both HPV copy number and HMGA2 protein expression were higher in cervical cancer than CIN samples. Area under the curve (AUC) values for HMGA2 expression and HPV copy number were 0.910 (95% CI: 0.844–0.976) and 0.848 (95% CI: 0.772–0.923), respectively. Expression of Bcl-2 and Caspase 3 can indicate the cell proliferation and apoptosis. Transfection of HMGA2 siRNA decreased HMGA2 mRNA and protein expression, Bcl-2 expression, inhibited cell proliferation, and increased Caspase 3 expression and apoptosis in SiHa, CaSki and S12 cervical cancer cells. HMGA2 overexpression had the opposite effects. These results suggest that elevated HMGA2 expression is associated with transformation of CIN into cervical cancer and that HMGA2 might be a useful biomarker for assessing the risk of cervical lesion progression.

Tetrac downregulates β-catenin and HMGA2 to promote the effect of resveratrol in colon cancer.

The molecular pathogenesis of colorectal cancer encompasses the activation of several oncogenic signaling pathways that include the Wnt/β-catenin pathway and the overexpression of high mobility group protein A2 (HMGA2). Resveratrol - the polyphenolic phytoalexin - binds to integrin αvβ3 to induce apoptosis in cancer cells via cyclooxygenase 2 (COX-2) nuclear accumulation and p53-dependent apoptosis. Tetraiodothyroacetic acid (tetrac) is a de-aminated derivative of l-thyroxine (T4), which - in contrast to the parental hormone - impairs cancer cell proliferation. In the current study, we found that tetrac promoted resveratrol-induced anti-proliferation in colon cancer cell lines, in primary cultures of colon cancer cells, and in vivo The mechanisms implicated in this action involved the downregulation of nuclear β-catenin and HMGA2, which are capable of compromising resveratrol-induced COX-2 nuclear translocation. Silencing of either β-catenin or HMGA2 promoted resveratrol-induced anti-proliferation and COX-2 nuclear accumulation which is essential for integrin αvβ3-mediated-resveratrol-induced apoptosis in cancer cells. Concurrently, tetrac enhanced nuclear abundance of chibby family member 1, the nuclear β-catenin antagonist, which may further compromise the nuclear β-catenin-dependent gene expression and proliferation. Taken together, these results suggest that tetrac targets β-catenin and HMGA2 to promote resveratrol-induced-anti-proliferation in colon cancers, highlighting its potential in anti-cancer combination therapy.

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.

High mobility group A1 protein modulates autophagy in cancer cells

High Mobility Group A1 (HMGA1) is an architectural chromatin protein whose overexpression is a feature of malignant neoplasias with a causal role in cancer initiation and progression. HMGA1 promotes tumor growth by several mechanisms, including increase of cell proliferation and survival, impairment of DNA repair and induction of chromosome instability. Autophagy is a self-degradative process that, by providing energy sources and removing damaged organelles and misfolded proteins, allows cell survival under stress conditions. On the other hand, hyper-activated autophagy can lead to non-apoptotic programmed cell death. Autophagy deregulation is a common feature of cancer cells in which has a complex role, showing either an oncogenic or tumor suppressor activity, depending on cellular context and tumor stage. Here, we report that depletion of HMGA1 perturbs autophagy by different mechanisms. HMGA1-knockdown increases autophagosome formation by constraining the activity of the mTOR pathway, a major regulator of autophagy, and transcriptionally upregulating the autophagy-initiating kinase Unc-51-like kinase 1 (ULK1). Consistently, functional experiments demonstrate that HMGA1 binds ULK1 promoter region and negatively regulates its transcription. On the other hand, the increase in autophagosomes is not associated to a proportionate increase in their maturation. Overall, the effects of HMGA1 depletion on autophagy are associated to a decrease in cell proliferation and ultimately impact on cancer cells viability. Importantly, silencing of ULK1 prevents the effects of HMGA1-knockdown on cellular proliferation, viability and autophagic activity, highlighting how these effects are, at least in part, mediated by ULK1. Interestingly, this phenomenon is not restricted to skin cancer cells, as similar results have been observed also in HeLa cells silenced for HMGA1. Taken together, these results clearly indicate HMGA1 as a key regulator of the autophagic pathway in cancer cells, thus suggesting a novel mechanism through which HMGA1 can contribute to cancer progression.

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

Background:Pancreatic cancer is currently the third leading cause of cancer deaths in the United States and it is predicted to become the second by the year 2030. High-mobility group A1 protein (HMGA1) is an oncogenic transcription factor, localised and active in cell nuclei, that is linked to tumour progression in many human cancers, including pancreatic cancer. Overexpression of HMGA1 renders cancer cells resistant to chemotherapy. Although the Ptf1a-Cre; LSL-KrasG12D transgenic mouse is perhaps the most widely utilised animal model for human pancreatic cancer, expression levels of HMGA1 in pancreata from this mouse model have not been characterised.Methods:Quantitative immunohistochemical analysis was used to determine nuclear HMGA1 levels in pancreatic tissue sections from Ptf1a-Cre; LSL-KrasG12D mice aged 5, 11, and 15 months. The H Score method was used for quantitative analysis.Results:The HMGA1 levels were significantly elevated in pancreatic intraepithelial neoplasia (PanIN) epithelia compared with untransformed acinar tissues or fibroinflammatory stroma.Conclusions:The PanINs have long been regarded as precancerous precursors to pancreatic adenocarcinoma. Significantly elevated HMGA1 levels observed in the nuclei of PanINs in Ptf1a-Cre; LSL-KrasG12D mice validate this animal model for investigating the role that HMGA1 plays in cancer progression and testing therapeutic approaches targeting HMGA1 in human cancers.

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

BackgroundHigh 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.MethodsThe 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.ResultsSix 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).ConclusionsThe 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.

HMGA2 plays an important role in Cr (VI)‐induced autophagy

Cr (VI) is mutagenic and carcinogenic, but the mechanism is unclear. In this study, the involvement of high mobility group A2 (HMGA2) in Cr (VI)-induced autophagy was investigated. Cr (VI) treatment induced formation of autophagosomes, increased expression of LC3II, Atg12-Atg5, Atg4, Atg10, HMGA1 and HMGA2 proteins, and decreased the expression of p62 in A549 cells. Silencing of HMGA2 gene by siRNA blocked Cr (VI)-induced formation of autophagosomes, expression of LC3II, Atg12-Atg5, Atg10 and reduction of p62. Overexpression of HMGA2 in HEK 293 and HeLa cells could induce the expression of LC3II, Atg12-Atg5 and Atg10, and decrease the expression of p62. Although the protein level of Atg12-Atg5 conjugation changed after Cr (VI) treatment, silencing of HMGA2 and overexpression of HMGA2, both the proteins and mRNA levels of Atg12 and Atg5 were not changed significantly. ChIP assay demonstrated that HMGA2 protein directly bound to the promoter sequence of Atg10 gene, which modulated the conjugation of Atg12-Atg5. Interestingly, 3-MA markedly prevented Cr (VI)-induced cell growth of A549 cells. Our further in vivo study confirmed that the expression of HMGA1, HMGA2, LC3II, Atg12-Atg5, Atg4, Atg5, Atg7, Atg10, Atg12, Beclin 1 were increased and p62 was reduced in lung tissues of Cr (VI)-treated BALB/c mice. Combining, our data demonstrated that HMGA2 plays an important role in Cr (VI)-induced autophagy and the mechanism underlies Atg12-Atg5 conjugation modulated by HMGA2-dependent transcriptional regulation of Atg10. This suggests that HMGA2 might be an important biomarker in Cr (VI)-induced autophagy, cell-growth or other toxicities.

Dovitinib enhances temozolomide efficacy in glioblastoma cells.

The multikinase inhibitor and FDA‐approved drug dovitinib (Dov) crosses the blood–brain barrier and was recently used as single drug application in clinical trials for GB patients with recurrent disease. The Dov‐mediated molecular mechanisms in GB cells are unknown. We used GB patient cells and cell lines to show that Dov downregulated the stem cell protein Lin28 and its target high‐mobility group protein A2 (HMGA2). The Dov‐induced reduction in pSTAT3Tyr705 phosphorylation demonstrated that Dov negatively affects the STAT3/LIN28/Let‐7/HMGA2 regulatory axis in GB cells. Consistent with the known function of LIN28 and HMGA2 in GB self‐renewal, Dov reduced GB tumor sphere formation. Dov treatment also caused the downregulation of key base excision repair factors and O6‐methylguanine‐DNA‐methyltransferase (MGMT), which are known to have important roles in the repair of temozolomide (TMZ)‐induced alkylating DNA damage. Combined Dov/TMZ treatment enhanced TMZ‐induced DNA damage as quantified by nuclear γH2AX foci and comet assays, and increased GB cell apoptosis. Pretreatment of GB cells with Dov (‘Dov priming’) prior to TMZ treatment reduced GB cell viability independent of p53 status. Sequential treatment involving ‘Dov priming’ and alternating treatment cycles with TMZ and Dov substantially reduced long‐term GB cell survival in MGMT+ patient GB cells. Our results may have immediate clinical implications to improve TMZ response in patients with LIN28+/HMGA2+ GB, independent of their MGMT methylation status.

HMGA2 promotes vasculogenic mimicry and tumor aggressiveness by upregulating Twist1 in gastric carcinoma

High mobility group protein A2 (HMGA2) is a transcription factor that plays an important role in the invasion and metastasis of gastric carcinoma (GC). The term vasculogenic mimicry (VM) refers to the unique ability of aggressive tumour cells to mimic the pattern of embryonic vasculogenic networks. However, the relationship between HMGA2 and VM formation remains unclear. In the present study, we examined concomitant HMGA2 expression and VM in 228 human GC samples and 4 GC cell lines. Our data indicate that HMGA2 is not only significantly associated with VM formation but also influences the prognosis of patients with gastric carcinoma. Overexpression of HMGA2 significantly increased cell motility, invasiveness, and VM formation both in vitro and in vivo. A luciferase reporter assay, Co-IP and ChIP demonstrated that HMGA2 induced the expression of Twist1 and VE-cadherin by binding to the Twist1 promoter. Moreover, we observed a decrease in VE-cadherin following Twist1 knockdown in cells overexpressing HMGA2. This study indicates that HMGA2 promotes VM in GC via Twist1-VE-cadherin signalling and influences the prognosis of patients with GC.

Prognostic significance of HMGA1 and HMGA2 proteins expressions in pancreatic carcinoma

Objective To study the expressions and prognostic significance of high mobility group protein A1 (HMGA1) and high mobility group protein A2 (HMGA2) in pancreatic carcinoma. Methods The expressions of HMGA1 and HMGA2 were examined by immunohistochemical SP method in 60 cases of pancrea-tic carcinoma and 30 cases of normal pancreatic tissues. The relationship between the expression and prognosis was also analyzed. Results The expressions of HMGA1 and HMGA2 in pancreatic carcinoma were significantly higher than those in normal tissues, and the positive expression rates were 70.0% vs. 6.7% (χ2=32.105, P=0.000) and 73.3% vs. 3.3%(χ2=39.200, P=0.000). The expression of HMGA1 in pancreatic carcinoma was correlated with histological grade (χ2=6.774, P=0.034), TNM stage (χ2=4.776, P=0.029) and lymphatic metastasis (χ2=12.614, P=0.000). The expression of HMGA2 in pancreatic carcinoma was correlated with histological grade (χ2=8.200, P=0.017) and TNM stage (χ2=7.253, P=0.007). The expression of HMGA1 was positively associated with HMGA2 expression(r=0.393, P=0.001). Kaplan-Meier analysis showed that the median survival time of HMGA1 and HMGA2 positive patients were shorter than those patients with HMGA1 negative and HMGA2 negative (14.0 months vs. 24.0 months, χ2=14.568, P=0.000; 15.0 months vs. 21.0 months, χ2=7.270, P=0.007). Conclusion HMGA1 and HMGA2 are highly expressed in pancreatic carcinoma, and play synergistic roles in the generation and progress of pancreatic carcinoma. There is certain value of combined detection of HMGA1 and HMGA2 to predict the prognosis of pancreatic carcinoma. Key words: Pancreatic neoplasms; HMGA proteins

Evaluation of the High Mobility Group A1 proteins (HMGA1) as a key mediate in the anticancer activity of ‐EF24.

The architectural chromatin binding proteins High Mobility Group A1 (HMGA1) are some of the most overexpressed proteins in malignant cancers and induce neoplastic transformation. The protein is increased as the last step of a prominent colon cancer progression pathway and mediates drug resistance, therefore correlating with a poor patient prognosis. HMGA1‐‐mediated chemoresistance results from a self‐protective process called cellular senescence. Analogs of the antioxidant, curcumin, when used in combination with traditional chemotherapeutic agents, are useful treatment options for drug resistant tumors. This study had two specific aims. The first being to investigate how colon cancer cells HCT116 respond to treatment with EF24. The second aim was to evaluate how hmga1 expression changed as a result of treatment with EF24. Our preliminary findings showed that cell viability decreased after 24‐hour treatment with low‐dose EF24, as indicated by an MTS assay, with notable discrepancies between cells that underwent a pulsed treatment regimen versus those that underwent continuous treatment. Furthermore, we demonstrated that cells exhibited fragmented DNA when treated with low‐dose EF24, which is characteristic of apoptotic cells. At higher, pulsed doses, senescence activity increased indicating the induction of a senescence pathway. Lastly, gene expression studies indicated that hmga1 was significantly down regulated in cells treated with continuous, low‐‐dose EF24. Further investigation of this pathway could lead to decreased toxicity and increased viability of combination cancer therapies.Support or Funding InformationThe research support is provided by the National Center for Research Resources (5 P20 RR16461), the National Institute of General Medical Sciences (8 P20 GM103499) from the National Institutes of Health, and the Winthrop McNair Scholars program.