Increased high-mobility group A2 correlates with lymph node metastasis and prognosis of non-small cell lung cancer

CircRNA High Mobility Group At-hook 2 regulates cell proliferation, metastasis and glycolytic metabolism of nonsmall cell lung cancer by targeting miR-331-3p to upregulate High Mobility Group At-hook 2

Increasing circular RNAs (circRNAs) have been identified as pivotal players in nonsmall cell lung cancer (NSCLC). The study will explore the function and mechanism of circRNA High Mobility Group AT-hook 2 (circHMGA2) in NSCLC. The circHMGA2, microRNA-331-3p (miR-331-3p) and HMGA2 expression analyses were performed via quantitative real-time PCR. Cell proliferation was assessed via Cell Counting Kit-8 and colony formation assays. Transwell migration/invasion assays were used for measuring cell metastasis. Glucose consumption and lactate production were determined for glycolytic evaluation. Western blot was used to detect the protein expression of HMGA2 and glycolytic markers. Target analysis was performed by dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Xenograft tumor assay in mice was conducted for the investigation of circHMGA2 in vivo . CircHMGA2 was overexpressed in NSCLC, and high circHMGA2 level might be related to NSCLC metastasis and poor prognosis. In-vitro assays suggested that NSCLC cell growth, metastasis and glycolysis were retarded by downregulation of circHMGA2. Upregulation of HMGA2 was shown to return the anticancer response of circHMGA2 knockdown in NSCLC cells. Through interacting with miR-331-3p, circHMGA2 could regulate the expression of HMGA2. In addition, circHMGA2/miR-331-3p and miR-331-3p/HMGA2 axes were affirmed in NSCLC regulation. In-vivo analysis indicated that circHMGA2 inhibition also reduced tumorigenesis and glycolysis of NSCLC via the miR-331-3p/HMGA2 axis. This study disclosed the oncogenic role of circHMGA2 and the regulatory circHMGA2/miR-331-3p/HMGA2 axis in NSCLC.

Identification of exosomal circRNA CD226 as a potent driver of nonsmall cell lung cancer through miR-1224-3p/high mobility group AT-hook 2 axis

Circular RNAs (circRNAs) are crucial for the pathogenesis of nonsmall lung cancer (NSCLC). Here, we set out to unravel the precise function of circRNA CD226 (circCD226) in NSCLC pathogenesis. The exosomes from serum specimens were observed by transmission electron microscopy. CircCD226, miR-1224-3p and high mobility group AT-hook 2 (HMGA2) were quantified by qRT-PCR, western blot and immunohistochemistry. Actinomycin D and Ribonuclease (RNase) R treatments and subcellular localization assay were used for circCD226 characterization. Cell viability, proliferation, migration, invasion and sphere formation abilities were gauged by CCK-8, EDU, wound-healing, transwell and sphere formation assays, respectively. Directed relationships among circCD226, miR-1224-3p and HMGA2 were examined by RNA pull-down, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The abundance of circCD226 was elevated in serum exosomes, tissues and cells of NSCLC. NSCLC serum exosomes enhanced NSCLC cell proliferation, migration, invasion and stemness. Loss of circCD226 impeded cell proliferation, migration, invasion and stemness in vitro, as well as tumor growth in vivo. Mechanistically, circCD226 sponged miR-1224-3p, and miR-1224-3p targeted HMGA2. CircCD226 involved the posttranscriptional regulation of HMGA2 through miR-1224-3p. Moreover, the miR-1224-3p/HMGA2 axis was identified as a functionally downstream effector of circCD226 in regulating NSCLC cell behaviors. Our study identifies circCD226 as a potential driver in NSCLC development depending on the regulation of miR-1224-3p/HMGA2 axis.

Nitrogen Metabolism Disorder Accelerates Occurrence and Development of Lung Adenocarcinoma: A Bioinformatic Analysis and In Vitro Experiments

Background

Nitrogen metabolism (NM) plays a pivotal role in immune regulation and the occurrence and development of cancers. The aim of this study was to construct a prognostic model and nomogram using NM-related genes for the evaluation of patients with lung adenocarcinoma (LUAD).

Methods

The differentially expressed genes (DEGs) related to NM were acquired from The Cancer Genome Atlas (TCGA) database. Consistent clustering analysis was used to divide them into different modules, and differentially expressed genes and survival analysis were performed. The survival information of patients was combined with the expressing levels of NM-related genes that extracted from TCGA and Gene Expression Omnibus (GEO) databases. Subsequently, univariate Cox analysis and the least absolute shrinkage and selection operator (LASSO) regression were used to build a prognostic model. GO and KEGG analysis were elaborated in relation with the mechanisms of NM disorder (NMD). Meanwhile, immune cells and immune functions related to NMD were discussed. A nomogram was built according to the univariate and multivariate Cox analysis to identify independent risk factors. Finally, real-time fluorescent quantitative PCR (RT-PCR) and Western bolt (WB) were used to verify the expression level of hub genes.

Results

There were 138 differential NM-related genes that were divided into two gene modules. Sixteen NM-related genes were used to build a prognostic model and the receiver operating characteristic curve (ROC) showed that the efficiency was reliable. GO and KEGG analysis suggested that NMD accelerated development of LUAD through the Wnt signaling pathway. The level of activated dendritic cells (aDCs) and type II interferon response in the low-risk group was higher than that of the high-risk group. A nomogram was constructed based on ABCC2, HMGA2, and TN stages, which was identified as four independent risk factors. Finally, RT-PCR and WB showed that CDH17, IGF2BP1, IGFBP1, ABCC2, and HMGA2 were differently expressed between human lung fibroblast (HLF) cells and cancer cells.

Conclusions

High NM levels were revealed as a poor prognosis of LUAD. NMD regulates immune system through affecting aDCs and type II interferon response. The prognostic model with NM-related genes could be used to effectively evaluate the outcomes of patients.

The circ-PITX1 promotes non-small cell lung cancer development via the miR-30e-5p/ITGA6 axis

Non-small cell lung cancer (NSCLC) is one of the most prevalent tumors with high incidence and mortality across the globe. Recently, increasing studies have demonstrated that circular RNAs (circRNAs) exert outstanding functions in NSCLC progression. Notwithstanding, we are still in the dark about the function and exact mechanism of circ-PITX1, a newly discovered circRNA. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) confirmed the profile of circ-PITX1 in NSCLC tissues and adjacent normal tissues. Gain- and loss- of function assay verified the impact of circ-PITX1 and miR-30e-5p on the proliferation, invasion, and migration of NSCLC cells (H1975 and A549). Bioinformatics analysis corroborated the downstream mechanisms of circ-PITX1. Dual-luciferase reporter gene assay and RNA immunoprecipitation (RIP) examined the interactions between circ-PITX1 and miR-30e-5p, miR-30e-5p and ITGA6. The protein levels of ITGA6, PI3K, AKT were determined by Western blot. circ-PITX1 was substantially up-regulated in NSCLC tissues and cells, and circ-PITX1 up-regulation was correlated with NSCLC patients’ poor survival. Functionally, circ-PITX1 overexpression or miR-30e-5p inhibition markedly facilitated proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), reduced apoptosis, and enhanced ITGA6/PI3K/AKT expression in NSCLC cells, whereas circ-PITX1 knockdown or miR-30e-5p up-regulation resulted in the opposite results. Mechanistically, circ-PITX1 acted as a sponge of miR-30e-5p, which targeted the 3ʹuntranslated region (UTR) of ITGA6. Knockdown of circ-PITX1 or overexpressing miR-30e-5p reduced ITGA6/PI3K/AKT axis. circ-PITX1 modulates the miR-30e-5p/ITGA6 axis to boost NSCLC progression, hence functioning as an oncogene.

circUBAP2 regulates osteosarcoma progression via the miR‑204‑3p/HMGA2 axis

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.

Emerging roles for HMGA2 in colorectal cancer

HMGA2 (High Mobility Group AT-hook 2) has been reported to promote colorectal cancer (CRC) development by regulating the transcription of target genes. It participates in nearly all aspects of cellular processes, including cell transformation, proliferation, apoptosis, senescence, metastasis, epithelial-to-mesenchymal transition (EMT), DNA repair and stem cell self-renewal. In the past decades, a group of downstream targets and binding partners have been identified in a wide range of cancers. Our findings of HMGA2 as a key factor in the MDM2/p53, IL11/STAT3 and Wnt/β-catenin signaling pathways prompt us to summarize current advances in the functional and molecular basis of HMGA2 in CRC. In this review, we address the roles of HMGA2 in the oncogenic networks of CRC based on recent advances. We review its aberrant expression, explore underlying mechanisms, discuss its pro-tumorigenic effects, and highlight promising small-molecule inhibitors based on targeting HMGA2 here. However, the understanding of HMGA2 in CRC progression is still elusive, thus we also discuss the future perspectives in this review. Collectively, this review provides novel insights into the oncogenic properties of HMGA2, which has potential implications in the diagnosis and treatment of CRC.

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HMGA2 promotes colorectal cancer (CRC) development by regulating the transcriptions of target genes.

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Circulating cell-free HMGA2 mRNA has been identified as a potential screening marker in CRC.

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HMGA2 appears to be a key factor in the networks of MDM2/p53, IL11/STAT3 and Wnt/β-catenin signaling pathways in CRC.

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Many agents and siRNAs serve as potential therapeutic approaches by targeting HMGA2 for the treatment of CRC.

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Deciphering HMGA2-mediated machinery helps to conceive effective therapy strategies and develop novel inhibitors in CRC.

Transcriptomic analysis reveals a WNT signaling pathway-based gene signature prognostic for non-small cell carcinoma

The value of combining multiple candidate genes into a panel to improve biomarker performance is increasingly emphasized. Genes associated with WNT signaling are widely-reported to provide prognostic signatures in non-small cell carcinoma (NSCLC). Screening of genes involved in this signaling pathway facilitated selection of an optimal candidate biomarker gene combination and development of an NSCLC prognostic model based on expression of these genes. Risk scores derived from the model performed well in predicting survival; in the training dataset, samples achieving a high risk score exhibit a shorter survival interval (median survival time 34.8 months, 95% CI 31.1-41.0) than did samples achieving a low risk score (median survival time 72.0 months, 95% CI 59.3-87.5, p=2e-11), and exhibited higher oncogene and lower tumor suppressor gene expression. Receiver-operator characteristic curves based on three-year survival demonstrate that the model outperformed clinical prognostic indicators. In addition, the model was validated in four independent cohorts, demonstrating robust NSCLC prognostic value. Correlation analyses reveal that the model offers efficacy independent of other clinical indicators. Gene Set Enrichment Analysis (GSEA) reveals that the model reflects variable tissue functional states relevant to NSCLC biology. In summary, the signature model shows potential as a valuable and robust NSCLC prognostic indicator.

Cr (VI) induced mitophagy via the interaction of HMGA2 and PARK2

Chromium (Cr) (VI) is a proven toxin, mutagen and carcinogen. Here, the role of high mobility group A2 (HMGA2) mediating Cr (VI)-induced mitophagy was investigated. Cr (VI)-treatment caused the formation of double membrane autophagic vesicles (AVs) engulfing mitochondria and increased the expression of PINK1, PARK2, LC3 as well as HMGA2 particularly in mitochondria in A549 cells. Silencing of HMGA2 by siRNA decreased expression of PINK1, PARK2 and LC3 II especially in mitochondria, while over-expression of HMGA2 increased the expression of them in A549 cells. It indicated that HMGA2 played a critical role in Cr (VI)-induced mitophagy. Most importantly, the results of co-immunoprecipitation showed for the first time that HMGA2 could bind to PARK2 in mitochondria to activate the mitophagy pathway. In BALB/c mice, Cr (VI) increased the expression of PINK1 and PARK2 in lung tissues. Furthermore, over-expression of HMGA2 in BALB/c mice by transfection of plasmid HMGA2 significantly increased the levels of PINK1, PARK2 and LC3 II in lung tissues. Collectively, our data demonstrated that HMGA2 plays an important role in Cr (VI)-induced mitophagy through direct interaction with PARK2 in A549 cells and lung tissue.

Knockdown of lncRNA ZFAS1-suppressed non-small cell lung cancer progression via targeting the miR-150-5p/HMGA2 signaling

Non-small cell lung cancer (NSCLC) is the main type of lung malignancy. Early diagnosis and treatments for NSCLC are far from satisfactory due to the limited knowledge of the molecular mechanisms regarding NSCLC progression. Long noncoding RNA (lncRNA) ZNFX1 antisense RNA1 (ZFAS1) has been implicated for its functional role in the progression of malignant tumors. This study aimed to determine the ZFAS1 expression from lung cancer clinical samples and to explore the molecular mechanisms underlying ZFAS1-modulated NSCLC progression. Experimental assays revealed that clinical samples and cell lines of lung malignant tumors showed an upregulation of ZFSA1. ZFAS1 expression was markedly upregulated in the lung tissues from patients with advanced stage of this malignancy. The loss-of-function assays showed that knockdown of ZFAS1-suppressed NSCLC cell proliferative, as well as invasive potentials, increased NSCLC cell apoptotic rates in vitro and also attenuated tumor growth of NSCLC cells in the nude mice. Further experimental evidence showed that ZFAS1 inversely affected miR-150-5p expression and positively affected high-mobility group AT-hook 2 (HMGA2) expression in NSCLC cell lines. MiR-150-5p inhibition or HMGA2 overexpression counteracted the effects of ZFAS1 knockdown on NSCLC cell proliferative, invasive potentials and apoptotic rates. In light of examining the clinical lung cancer samples, miR-150-5p expression was downregulated and the HMGA2 expression was highly expressed in the lung cancer tissues compared with normal ones; the ZFAS1 expression showed a negative correlation with miR-150-5p expression but a positive correlation with HMGA2 expression in lung cancer tissues. To summarize, we, for the first time, demonstrated the inhibitory effects of ZFAS1 knockdown on NSCLC cell progression, and the results from mechanistic studies indicated that ZFAS1-mediated NSCLC progression cells via targeting miR-150-5p/HMGA2 signaling.

miR-491 inhibits BGC-823 cell migration via targeting HMGA2

PURPOSE

miR-491 functions as a tumor suppressor in several types of cancer. However, its function and mechanism in gastric cancer proliferation and metastasis have not been well defined. The aim of this study was to explore the role and regulatory mechanism of miR-491 in cell proliferation and migration in gastric cancer.

METHODS

Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to detect the expression pattern of miR-491 in gastric cancer tissues. miR-491 overexpression vector, miR-491 inhibitor, and siHMGA2 were used; and MTT, wound healing, and transwell assays were employed to examine proliferation and migration for BGC-823 cells. A dual-luciferase reporter gene was used to measure the target relationship between miR-491 and HMGA2.

RESULTS

Most gastric cancer patients exhibit decreased miR-491 expression. miR-491 overexpression inhibited cell proliferation and migration, whereas miR-491 inhibitor treatment produced the opposite effect. Mechanistically, HMGA2 was identified as a direct target of miR-491. Moreover, HMGA2 knockdown inhibited cell proliferation and migration, which was similar to the effect of miR-491 overexpression. HMGA2 was decreased after transfection of the miR-491 vector and increased after transfection of the miR-491 inhibitor.

CONCLUSION

Our results suggest that miR-491 suppressed cell proliferation and cell motility in gastric cancer by targeting HMGA2. Silencing HMGA2 produced a similar effect to miR-491 overexpression on cell proliferation and migration. miR-491/HMGA2 signaling may be a potential therapeutic target for gastric cancer patients with decreased miR-491 expression.

Metastases with definitive pathological diagnosis but no detectable primary tumor: A surveillance epidemiology and end results-based study

Background

This study investigates the characteristics of a special type of cancer of unknown primary site (CUP, type 2), which is a metastasis of a definite pathological diagnosis without a detectable primary site.

Patients and methods

Patients diagnosed between 2004 and 2014 were identified from the Surveillance Epidemiology and End Results (SEER) database. The characteristics of type 2 CUP from different sources were analyzed. For each source of type 2 CUP, tumors of the corresponding T_nN_0‐XM₁ stage were used as controls.

Results

A total of 8505 patients with type 2 CUP were included in this analysis. Type 2 CUP shows an increasing trend, while type 1 shows the opposite. Type 2 CUPs have significant differences with stage IV of the same pathological primary lesion. Many characteristics influenced the prognosis of type 2 CUP patients, including marital status, age, race, sex, registration time, lymph node metastasis, surgery, chemotherapy, and radiation.

Conclusion

Our study suggests that identifying the source of metastasis is the key to the selection of treatment and the determination of the prognosis for CUP.

Impact of high-mobility-group A2 overexpression on epithelial-mesenchymal transition in pancreatic cancer

Background: Tumor metastasis causes high mortality in patients with malignancies. In carcinomas, overexpression of high-mobility-group A2 (HMGA2) in cancer cells would lead to tumor development and epithelial to mesenchymal transition (EMT), promoting metastasis. This study evaluated HMGA2 overexpression for its effects on pancreatic cancer (PC).

Methods: HMGA2 protein levels were immunohistochemically assessed in human PC tissue specimens and evaluated for associations with patients’ clinicopathological findings. In human PC CAPAN 1 cells after HMGA2 expression was silenced or overexpressed, Transwell migration and invasion assays were performed, and EMT marker levels (E-cadherin, N-cadherin and Vimentin) were determined by immunoblot.

Results: HMGA2 and Vimentin were found in 43% and 45% of PC tissue samples, respectively, while E-cadherin was absent in 60%. HMGA2 expression, loss of E-cadherin and Vimentin expression were significantly associated with clinical stage, tumor differentiation and lymph node metastasis. More importantly, univariate and multivariate analysis demonstrated that HMGA2 expression is an independent prognostic factor for patients with pancreatic cancer. Meanwhile, HMGA2-silenced CAPAN 1 cells showed reduced migration and invasion ability while HMGA2-overexpressed CAPAN 1 cells showed increased migration and invasion ability. Increased E-cadherin (epithelial marker) and reduced N-cadherin and Vimentin (mesenchymal markers) were found in HMGA2-silenced cells, while reduced E-cadherin and increased N-cadherin and Vimentin were found in HMGA2-overexpressed cells. Furthermore, Snail and Zeb1 (transcriptional factors) were reduced in HMGA2-silenced cells and increased in HMGA2-overexpressed cells.

Conclusion: Our findings demonstrate that HMGA2 expression correlates with advanced tumor grades, lymph node metastasis and poor prognosis and may be a novel prognosis/therapeutic marker for PC.