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Circular RNA (circRNA/circ)-ubiquitin associated protein 2 (UBAP2), a newly recognized circRNA, serves a functional role in several types of tumor, including ovarian cancer, colorectal cancer and osteosarcoma. However, the precise roles and molecular mechanism under-lying circUBAP2 in osteosarcoma (OS) are not completely understood. In the present study, the expression levels of circUBAP2, microRNA (miR)-204-3p and (HMGA2) were evaluated via reverse transcription-quantitative PCR in OS tissues and cells. OS cell proliferation, migration, invasion and apoptosis were assessed by performing Cell Counting Kit-8, Transwell and flow cytometry assays, respectively. HMGA2 protein expression levels were determined via western blot-ting. Dual-luciferase reporter assays were performed to verify the interaction between circUBAP2 and miR-204-3p, and between miR-204-3p and HMGA2. An RNA immunoprecipitation (RIP) assay was conducted to confirm the interaction between circUBAP2 and miR-204-3p. The results demonstrated that circUBAP2 expression was significantly upregulated in OS tissues and cell lines compared with para-cancerous tissues and hFOB1.19 cells, respectively. In addition, high circUBAP2 expression levels in patients with OS were associated with a lower survival rate compared with lower expression levels in patients with OS. The functional assays revealed that circUBAP2 knockdown significantly inhibited OS cell proliferation, migration and invasion, but increased OS cell apoptosis compared with the small interfering RNA-negative control (si-NC) group. The dual-luciferase reporter and RIP assay results confirmed that circUBAP2 bound to miR-204-3p. Moreover, miR-204-3p expression was significantly downregulated in OS tissues compared with paracancerous tissues, and miR-204-3p expression was negatively correlated with circUBAP2 expression in OS tissues. Collectively, the results demonstrated that miR-204-3p was associated with circUBAP2 knockdown-mediated inhibition of OS cell malignant behavior. Moreover, miR-204-3p was also identified as one of the direct targets of HMGA2. Collectively, the results indicated that compared with the si-NC group, circUBAP2 knockdown significantly inhibited OS cell malignant behavior by binding to miR-204-3p, which subsequently regulated HMGA2 expression. Therefore, the present study demonstrated that circUBAP2 expression was upregulated in OS, and circUBAP2 regulated OS cell malignant behavior via the miR-204-3p/HMGA2 axis.

Parkinson's disease (PD), a common multifactorial neurodegenerative disease, is characterized by irreversible loss of dopaminergic neurons in the substantia nigra. In-depth study of the pathogenesis of PD is of great importance. High-mobility group AT-hook 2 (HMGA2) has been proposed to be implicated with neuronal differentiation and impairment of cognitive function. However, whether HMGA2 plays a role in PD is rarely explored. In the present study, N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated PD mice models and N-methyl-4- phenylpyridinium (MPP+)-treated SH-SY5Y cell models were established. Reverse transcription-quantitative PCR showed that HMGA2 displayed low levels in brain tissues of MPTP-treated mice and MPP+-treated SH-SY5Y cells. Moreover, HMGA2 overexpression suppressed SH-SY5Y cell apoptosis. Additionally, let-7b-5p bound with HMGA2 3′ untranslated region (UTR), and its expression was negatively correlated with HMGA2 level. Moreover, let-7b-5p presented high levels in brain tissues of PD mice and MPP+-treated SH-SY5Y cells, and knockdown of let-7b-5p inhibited SH-SY5Y cell apoptosis. Rescue assays illustrated that HMGA2 neutralized the promotive effects of let-7b-5p mimics on SH-SY5Y cell apoptosis. In conclusion, the present study demonstrated that let-7b-5p contributes to cell apoptosis in PD by targeting HMGA2, which offers a potential theoretical basis for the study of effective therapy in PD.

This aim of the present study was to observe the effect of high mobility group AT-hook 2 (HMGA2) on the proliferation and invasion ability of ACHN renal cell carcinoma (RCC) cells. Human ACHN cells, an RCC cell line, and HKC normal human renal tubular epithelial cells were cultured. HMGA2 small interfering (si)RNA, Mock-siRNA and their negative control group were designed and synthesized. Subsequently, the ACHN cells were transiently transfected using RNA interference technology. Finally, the mRNA and protein expression levels of HMGA2 were detected using reverse transcription-polymerase chain reaction and western blot analyses. The proliferation ability of the ACHN cells was determined using MTT, and ACHN cell invasion ability was detected using the Transwell method. The results showed that the mRNA and protein expression levels of HMGA2 in the ACHN cells were considerably higher, compared with those in the HKC cells (P

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.

Diabetic nephropathy (DN) is one of the most common complications of diabetes mellitus (DM), and has been demonstrated as one of the major causes of renal failure. In a previous study, it was noted that microRNA let-7a-5p was downregulated in DN; however, the underlying mechanism requires additional investigation. The aim of the present study was to investigate the roles of let-7a-5p in the pathogenesis of DN and its associated mechanism. The renal tissues of db/db and db/m mice, and renal mesangial cells treated with high concentrations of glucose were obtained; reverse transcription-quantitative polymerase chain reaction, and western blot analysis were applied to detect the expression of let-7a-5p and high-mobility group AT-hook 2 (HMGA2) in vivo and in vitro. In addition, renal mesangial cells cultured under high-glucose conditions (20 and 30 mmol/l) were transfected with either let-7a-5p mimics or let-7a-5p inhibitors. The effects of let-7a-5p on the proliferation and apoptosis of renal mesangial cells were examined using CCK-8 and flow cytometry methods. Additionally, cells were collected and the expression of phosphoinositide 3-kinase (PI3K), phosphorylated protein kinase B (p-AKT) and HMGA2 was analyzed with western blot analysis. Finally, a dual luciferase reporter assay was performed to confirm whether HMGA2 was a direct target of let-7a-5p. Let-7a-5p was significantly downregulated and HMGA2 was markedly upregulated in the tissue samples of DN mice and renal mesangial cells cultured under high-glucose conditions. In addition, transfection of let-7a-5p mimics induced a significant decrease in the proliferation and increase in the apoptosis of renal mesangial cells cultured under high-glucose conditions; transfection of let-7a-5p inhibitors exhibited the opposite effects. Furthermore, transfection of let-7a-5p mimics also led to the inhibition of the PI3K-AKT signaling pathway; transfection of let-7a-5p inhibitors may activate the PI3K-AKT signaling pathway through the increase in PI3K and AKT levels. Finally, a dual luciferase reporter assay confirmed that HMGA2 is a direct target of let-7a-5p. Let-7a-5p was downregulated in DN and may participate in the pathogenesis of DN via regulating HMGA2 expression and the PI3K-AKT signaling pathway.

The present study aimed to investigate the expression of microRNA‑495 (miR‑495) in non‑small cell lung cancer (NSCLC) tissues and cells, as well as its function on the proliferation of lung cancer cells. The expression of miR‑495 in 122 pairs of NSCLC tissues and matched paracarcinoma tissues, as well as in human lung cancer cell lines (A549, H460, H1650, H520 and SK‑MES‑1) and the normal human pulmonary bronchial epithelial cell line 16HBE was determined using reverse transcription quantitative polymerase chain reaction (RT‑qPCR). As predicted by bioinformatics analysis, high mobility group A2 (HMGA2) may be a potential target gene of miR‑495. In addition, the regulatory function of miR‑495 on its target gene HMGA2 was evaluated using a dual‑luciferase reporter assay, RT‑qPCR and western blotting. Furthermore, the effect of miR‑495 on the proliferation of A549 lung cancer cells was investigated using a Cell Counting Kit‑8 (CCK‑8) assay. The results demonstrated that the expression of miR‑495 in NSCLC tissues and cells was significantly downregulated compared with the control. In addition, downregulated expression of miR‑495 was associated with tumor differentiation, lymph node metastasis and tumor, node and metastasis staging. Additionally, a dual‑luciferase reporter assay revealed that miR‑495 could directly associated with the 3'‑untranslated region of HMGA2. Upregulated expression of miR‑495 significantly downregulated the mRNA and protein expression levels of HMGA2 in A549 cells. Furthermore, the results of CCK‑8 assay revealed that upregulated expression of miR‑495 significantly suppressed the proliferation of A549 cells; HMGA2 overexpression reversed this inhibition. In summary, the findings of the present study demonstrated that miR‑495 was downregulated in NSCLC tissues and cells. In addition, miR‑495 suppressed the proliferation of lung cancer cells by directly targeting HMGA2.

High expression of high mobility group protein A2 (HMGA2) is correlated with the invasiveness of gastric cancer and is an independent prognostic factor. The reason may be that HMGA2 promotes epithelial-mesenchymal transition (EMT) and the acquisition of tumor stem cell properties, yet the mechanism remains unclear. In this study, immunohistochemistry and western blot analysis revealed that the expression of HMGA2 and Twist-related protein 1 (TWIST1) in gastric carcinoma tissues was higher than that in the peritumoral tissues and that the expression levels of these two proteins were positively correlated. The protein expression levels of HMGA2 and TWIST1 were high in the poorly differentiated gastric cancer MKN-45 cells and were low in the moderately differentiated SGC-7901 cells. TWIST1 was inhibited after HMGA2 interference and was significantly increased after overexpression of HMGA2. Luciferase experiments showed that TWIST1 was a direct downstream target gene of HMGA2. The simultaneous interference of HMGA2 expression and the overexpression of TWIST1 in MKN-45 cells reversed the inhibitory effect of HMGA2 interference on the invasion and migration of gastric cancer cells, EMT and the expression of stemness markers. However, the simultaneous overexpression of HMGA2 and the interference of TWIST1 expression in the SGC-7901 cells reversed the promoter effect of HMGA2 overexpression on the invasiveness and migration of gastric cancer cells, EMT and the expression of stemness markers. In addition, animal experiments showed that TWIST1 overexpression reversed the inhibition of HMGA2 interference on the metastasis of MKN-45 cells. Therefore, HMGA2 regulates the EMT of gastric cancer cells and the acquisition of tumor stem cell properties through direct regulation of the downstream target gene TWIST1.

Long non‑coding RNAs (lncRNAs) have been reported to be key regulators in various types of cancer, including lung adenocarcinoma (LAD). The roles of the lncRNA differentiation antagonizing non‑protein coding RNA (DANCR) and high mobility group AT‑hook 2 (HMGA2) in LAD remain unclear. In the present study, it was revealed that the lncRNA DANCR was upregulated in LAD tissue and cell lines, compared with para‑tumor tissue and a normal lung cell line. Additionally, elevated DANCR expression was associated with poor prognosis in the patients with LAD. Functionally, the study revealed that knockdown of DANCR inhibited invasion and HMGA2 expression in the LAD cell lines, SPCA1 and A549. Furthermore, HMGA2 was overexpressed in LAD tissue and in SPCA1 and A549 cells, compared with para‑tumor tissue and a normal lung cell line. Inhibition of HMGA2 suppressed the invasive ability of SPCA1 and A549 cells, and DANCR promoted the invasive ability via regulation of HMGA2 in SPCA1 and A549 cells. The findings of the present study revealed that DANCR promoted the invasion of LAD cells by positively regulating HMGA2. Thus, a DANCR/HMGA2 axis may be a novel potential target in the molecular treatment of LAD.

The importance of microRNAs (miRNAs) in cancer development has been widely recognized in recent decades. In the present study, the function and mechanism of miRNA-363-3p (miR-363-3p), formerly characterized as a tumor suppressor, in the hepatocarcinogenesis of liver cancer cells was investigated. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was applied to detect the expression of miR-363-3p in liver cancer tissues. Cell proliferation, survival and migration capacities were determined by MTT, colony formation and wound-healing assays, respectively. The targeting of high mobility group AT-hook 2 (HMGA2) mRNA by miR-363-3p was confirmed by bioinformatics analysis, and RT-qPCR, luciferase reporter and western blot assays. The correlation between the expression levels of HMGA2 and miR-363-3p was analyzed. The RT-qPCR results revealed that the levels of miR-363-3p were downregulated in liver cancer tissues. Cellular assays validated that miR-363-3p exerted tumor suppressing functions, including the inhibition of cell proliferation, survival and migration abilities in two liver cancer cell lines. Bioinformatics prediction and subsequent experiments demonstrated that HMGA2 was a direct target of miR-363-3p. Restoration of the expression of HMGA2 in miR-363-3p mimic-transfected cells reversed the tumor suppressing effects caused by miR-363-3p. Finally, there was a significant negative correlation between the expression levels of HMGA2 and miR-363-3p in liver cancer tissues. miR-363-3p was identified as an important tumor suppressor in liver cancer via targeting HMGA2, which may have potential benefits in liver cancer therapy.

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.

High-grade serous cancer (HGSC) is a lethal form of ovarian cancer due to invasion and early metastasis. Gain of epithelial-mesenchymal transition (EMT) contributes to the aggressiveness of HGSC. High-mobility gene group A2 (HMGA2), an architectural transcription factor, plays a major role in HGSC through the regulation of EMT gene expression. Based on the gene profiling analysis, we found that the potent EMT gene, stanniocalcin 2 (STC2), was highly correlated with HMGA2 expression. In the present study, we demonstrated that STC2 was directly regulated by HMGA2 at the transcriptional level. Overexpressing STC2 in vitro directly enhanced cell migration and invasion. To investigate the correlation of STC2 and HMGA2 expression and the potential biomarker for ovarian cancer, three independent large cohorts of ovarian cancer (cohort 1=278, cohort 2=150 and cohort 3=95 cases) were examined in the present study. The results showed that the expression of HMGA2 and STC2 was positively correlated. Furthermore, STC2 expression was significantly associated with tumor grade and histotype. HGSC had significantly higher levels of STC2 expression and was inversely correlated with patient survival. These findings suggested that STC2 is an important new biomarker that can be used for HGSC.

We describe two cases of extraskeletal osteochon-droma in which chromosome bands 12q14~15 were visibly rearranged through a pericentric inv(12). Molecular analysis of the first tumor showed that both transcript 1 (NM_003483) and transcript 2 (NM_003484) of HMGA2 were expressed. In the second tumor, the inv(12) detected by karyotyping had resulted in an HMGA2-SOX5 fusion transcript in which exons 1–3 of HMGA2 were fused with a sequence from intron 1 of SOX5. The observed pattern is similar to rearrangements of HMGA2 found in several other benign mesenchymal tumors, i.e., disruption of the HMGA2 locus leaves intact exons 1–3 which encode the AT-hook domains and separates them from the 3′-terminal part of the gene. Our data therefore show that a subset of soft tissue osteochondromas shares pathogenetic involvement of HMGA2 with lipomas, leiomyomas and other benign connective tissue neoplasms.

Malignant tumors of the vulva account for only 5% of cancers of the female genital tract in the USA. The most frequent cancers of the vulva are squamous cell carcinoma (SCC) and malignant melanoma (MM). Little is known about the genetic aberrations carried by these tumors. We report a detailed study of 25 vulva tumors [22 SCC, 2 MM, 1 atypical squamous cell hyperplasia (AH)] analyzed for expression of the high-mobility group AT-hook family member genes HMGA2 and HMGA1, for mutations in the IDH1, IDH2 and TERT genes, and for methylation of the MGMT promoter. The RT-PCR and immunohistochemistry analyses showed that HMGA2 was expressed in the great majority of analyzed samples (20 out of 24; SCC as well as MM) but not in the normal controls. HMGA1, on the other hand, was expressed in both tumors and normal tissues. Five of the 24 tumors (all SCC) showed the C228T mutation in the TERT promoter. Our results showed that HMGA2 and TERT may be of importance in the genesis and/or the progression of tumors of the vulva.

High-mobility group AT-hook 2 (HMGA2), a member of the high mobility group family, has been reported to correlate with cancer progression. However, there is no report concerning the correlation between HMGA2 and metastasis in renal cell carcinoma. In the present study, we found that HMGA2 was highly expressed in five renal cell carcinoma cell lines compared with that in the normal renal tubular epithelial HK2 cell line. Additionally, HMGA2 facilitated cell migration and invasion of renal cell carcinoma cells, as evidenced by wound healing and Transwell assays. Subsequently, our results revealed that the E-cadherin level was upregulated, while N-cadherin, Twist1 and Twist2 expression were downregulated in HMGA2-depleted ACHN cells. In contrast, overexpression of HMGA2 in 786-O cells enhanced epithelial-mesenchymal transition (EMT). In addition, analysis of the database Cancer Browser further validated the positive correlation between HGMA2 and Twist1 or Twist2 in renal cell carcinoma. Meanwhile, Kaplan-Meier analysis indicated that low HMGA2 expression was closely associated with an increased overall survival in renal cell carcinoma patients. To confirm the underlying mechanism of HMGA2-regulated EMT, our results revealed that silencing of HMGA2 downregulated the mRNA and protein levels of TGF-β and Smad2, while HMGA2 overexpression had the opposite effect. Furthermore, TGF-β overexpression could partially reverse the anti-metastatic effect and mesenchymal-epithelial transition (MET) by HMGA2 loss, while TGF-β deficiency impeded the pro-metastatic phenotype and high expression of EMT markers induced by HMGA2 overexpression. In summary, our results demonstrated that HMGA2 facilitated a metastatic phenotype and the EMT process in renal cell carcinoma cells in vitro through a TGF-β-dependent pathway. In addition, these data strongly suggest that HGMA2 may serve as a potential therapeutic target and prognostic biomarker against renal cell carcinoma in the future.

Extensive cytogenetic investigations of pleomorphic adenomas of the salivary glands have unequivocally demonstrated that they are cytogenetically monoclonal and are characterized by a high frequency of tumor specific chromosome abnormalities involving in particular chromosome bands 3p21, 8q12 and 12q14-15. Here we show that two radiation-associated and cytogenetically polyclonal adenomas without gross rearrangements of these breakpoints show simultaneous overexpression of the PLAG1 and HMGIC genes, i.e. the target genes of the 8q12 and 12q14-15 rearrangements in sporadic adenomas. In addition, one of the tumors expressed a cryptic CTNNB1-PLAG1 fusion transcript. Our findings strongly suggest that identical or very similar molecular mechanisms are operating during adenoma tumorigenesis irrespective of whether the tumors are cytogenetically polyclonal or whether they have non-random, tumor specific abnormalities. Cytogenetically polyclonal adenomas are thus most likely also of monoclonal origin.