Knockdown of COUP-TFII inhibits cell proliferation and induces apoptosis through upregulating BRCA1 in renal cell carcinoma cells

Identification of lncRNAs Deregulated in Epithelial Ovarian Cancer Based on a Gene Expression Profiling Meta-Analysis

Epithelial ovarian cancer (EOC) is one of the deadliest gynecological cancers worldwide, mainly because of its initially asymptomatic nature and consequently late diagnosis. Long non-coding RNAs (lncRNA) are non-coding transcripts of more than 200 nucleotides, whose deregulation is involved in pathologies such as EOC, and are therefore envisaged as future biomarkers. We present a meta-analysis of available gene expression profiling (microarray and RNA sequencing) studies from EOC patients to identify lncRNA genes with diagnostic and prognostic value. In this meta-analysis, we include 46 independent cohorts, along with available expression profiling data from EOC cell lines. Differential expression analyses were conducted to identify those lncRNAs that are deregulated in (i) EOC versus healthy ovary tissue, (ii) unfavorable versus more favorable prognosis, (iii) metastatic versus primary tumors, (iv) chemoresistant versus chemosensitive EOC, and (v) correlation to specific histological subtypes of EOC. From the results of this meta-analysis, we established a panel of lncRNAs that are highly correlated with EOC. The panel includes several lncRNAs that are already known and even functionally characterized in EOC, but also lncRNAs that have not been previously correlated with this cancer, and which are discussed in relation to their putative role in EOC and their potential use as clinically relevant tools.

NR2F2 controls malignant squamous cell carcinoma state by promoting stemness and invasion and repressing differentiation

The nongenetic mechanisms required to sustain malignant tumor state are poorly understood. During the transition from benign tumors to malignant carcinoma, tumor cells need to repress differentiation and acquire invasive features. Using transcriptional profiling of cancer stem cells from benign tumors and malignant skin squamous cell carcinoma (SCC), we identified the nuclear receptor NR2F2 as uniquely expressed in malignant SCC. Using genetic gain of function and loss of function in vivo, we show that NR2F2 is essential for promoting the malignant tumor state by controlling tumor stemness and maintenance in mouse and human SCC. We demonstrate that NR2F2 promotes tumor cell proliferation, epithelial-mesenchymal transition and invasive features, while repressing tumor differentiation and immune cell infiltration by regulating a common transcriptional program in mouse and human SCCs. Altogether, we identify NR2F2 as a key regulator of malignant cancer stem cell functions that promotes tumor renewal and restricts differentiation to sustain a malignant tumor state.

Overexpression of chemokine receptor lymphotactin receptor 1 has prognostic value in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is an aggressive subtype of renal cell carcinoma. X‐C motif chemokine receptor 1 (XCR1) exerts important roles in tumor progression; however, its role in ccRCC is unclear.

Methods

We utilized publicly available data from The Cancer Genome Atlas (TCGA) to assess the role of XCR1 in ccRCC and validated the results in 36 samples from patients with ccRCC who underwent curative resection in Xinqiao Hospital Chongqing. XCR1 overexpression was identified in ccRCC, which was confirmed by qRT‐PCR assay and immunohistochemical staining of ccRCC samples.

Results

For the TCGA and clinical data, Kaplan–Meier survival analysis revealed that higher XCR1 expression in ccRCC was related to longer overall survival. Cox regression analysis suggested that XCR1 is an independent risk factor for ccRCC. GSEA analysis suggested that XCR1 is associated with the JAK/STAT signaling pathway. XCR1 knockdown by small interfering RNA (siRNA) significantly increased ccRCC cell proliferation and migration, and decreased cell apoptosis.

Conclusion

We found higher XCR1 expression in ccRCC compared with that in normal tissues is related to longer overall survival in patients with ccRCC. XCR1 knockdown significantly increased RCC cells proliferation and migration, and decreased apoptosis. XCR1 might be used as a prognostic biomarker in ccRCC in the future.

BRCA1 subcellular localization regulated by PI3K signaling pathway in triple-negative breast cancer MDA-MB-231 cells and hormone-sensitive T47D cells

This study is to investigate the effect of the PI3K/Akt signaling pathway on the regulation of BRCA1 subcellular localization in triple-negative breast cancer (TNBC) MDA-MB-231 cells and hormone-sensitive T47D cells. We found that heregulin-activated T47D cells showed more nuclear localization of BRCA1, but BRCA1 nuclear localization decreased after the inhibition of the PI3K signaling pathway. In MDA-MB-231 cells, activation or inhibition of the PI3K signaling pathway did not significantly affect cell apoptosis and BRCA1 nuclear translocation (P > 0.05). However, in T47D cells, the activation of the PI3K pathway significantly increased cell apoptosis (P < 0.05). In the heregulin-activated MDA-MB-231 and T47D cells, the phosphorylation of Akt and BRCA1 was significantly increased (P < 0.05), while that was significantly reduced after PI3K pathway inhibition (P < 0.05). The changing trends of the mRNA levels of Akt and BRCA1 in MDA-MB-231 and T47D cells after PI3K pathway activation or inhibition were consistent with the trends of their proteins. In both MDA-MB-231 and T47D cells, BRCA1 phosphorylation is regulated by the PI3K signaling pathway, but the nuclear localization of BRCA1 is different in these two cell lines. Moreover, the apoptosis rates of these two cell lines are different.

Recent progress on the role and molecular mechanism of chicken ovalbumin upstream promoter-transcription factor II in cancer

Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) is an orphan receptor that regulates the expression of genes involved in development and homeostasis. COUP-TFII is also dysregulated in cancer, where it plays important roles in oncogenesis and malignant progression. Recent studies have also investigated altered microRNA-mediated regulation of COUP-TFII in cancer. Although many investigators have studied the expression and clinical significance of COUP-TFII in several cancer types, there remain many controversies regarding its role in these diseases. In this review, we will describe the functions and underlying molecular mechanisms of COUP-TFII in several cancers, especially colorectal, gastric, breast, and prostate cancer; additionally, we will briefly summarize what is known about microRNA-mediated regulation of COUP-TFII.

Oxidative DNA Damage Modulates DNA Methylation Pattern in Human Breast Cancer 1 (BRCA1) Gene via the Crosstalk between DNA Polymerase β and a de novo DNA Methyltransferase

DNA damage and base excision repair (BER) are actively involved in the modulation of DNA methylation and demethylation. However, the underlying molecular mechanisms remain unclear. In this study, we seek to understand the mechanisms by exploring the effects of oxidative DNA damage on the DNA methylation pattern of the tumor suppressor breast cancer 1 (BRCA1) gene in the human embryonic kidney (HEK) HEK293H cells. We found that oxidative DNA damage simultaneously induced DNA demethylation and generation of new methylation sites at the CpGs located at the promoter and transcribed regions of the gene ranging from -189 to +27 in human cells. We demonstrated that DNA damage-induced demethylation was mediated by nucleotide misincorporation by DNA polymerase β (pol β). Surprisingly, we found that the generation of new DNA methylation sites was mediated by coordination between pol β and the de novo DNA methyltransferase, DNA methyltransferase 3b (DNMT3b), through the interaction between the two enzymes in the promoter and encoding regions of the BRCA1 gene. Our study provides the first evidence that oxidative DNA damage can cause dynamic changes in DNA methylation in the BRCA1 gene through the crosstalk between BER and de novo DNA methylation.

COUP-TFII in Health and Disease

The nuclear receptors (NRs) belong to a vast family of evolutionary conserved proteins acting as ligand-activated transcription factors. Functionally, NRs are essential in embryogenesis and organogenesis and in adulthood they are involved in almost every physiological and pathological process. Our knowledge of NRs action has greatly improved in recent years, demonstrating that both their expression and activity are tightly regulated by a network of signaling pathways, miRNA and reciprocal interactions. The Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII, NR2F2) is a NR classified as an orphan due to the lack of a known natural ligand. Although its expression peaks during development, and then decreases considerably, in adult tissues, COUP-TFII is an important regulator of differentiation and it is variably implicated in tissues homeostasis. As such, alterations of its expression or its transcriptional activity have been studied and linked to a spectrum of diseases in organs and tissues of different origins. Indeed, an altered COUP-TFII expression and activity may cause infertility, abnormality in the vascular system and metabolic diseases like diabetes. Moreover, COUP-TFII is actively investigated in cancer research but its role in tumor progression is yet to be fully understood. In this review, we summarize the current understanding of COUP-TFII in healthy and pathological conditions, proposing an updated and critical view of the many functions of this NR.

Toll-like receptor 4 regulates spontaneous intestinal tumorigenesis by up-regulating IL-6 and GM-CSF

Inflammation is as an important component of intestinal tumorigenesis. The activation of Toll‐like receptor 4 (TLR4) signalling promotes inflammation in colitis of mice, but the role of TLR4 in intestinal tumorigenesis is not yet clear. About 80%–90% of colorectal tumours contain inactivating mutations in the adenomatous polyposis coli (Apc) tumour suppressor, and intestinal adenoma carcinogenesis in familial adenomatous polyposis (FAP) is also closely related to the germline mutations in Apc. The Apc^Min/+ (multiple intestinal neoplasia) model mouse is a well‐utilized model of FAP, an inherited form of intestinal cancer. In this study, Apc^Min/+ intestinal adenoma mice were generated on TLR4‐sufficient and TLR4‐deficient backgrounds to investigate the carcinogenic effect of TLR4 in mouse gut by comparing mice survival, peripheral blood cells, bone marrow haematopoietic precursor cells and numbers of polyps in the guts of Apc^Min/+ WT and Apc^Min/+ TLR4^−/− mice. The results revealed that TLR4 had a critical role in promoting spontaneous intestinal tumorigenesis. Significant differential genes were screened out by the high‐throughput RNA‐Seq method. After combining these results with KEGG enrichment data, it was determined that TLR4 might promote intestinal tumorigenesis by activating cytokine‐cytokine receptor interaction and pathways in cancer signalling pathways. After a series of validation experiments for the concerned genes, it was found that IL6, GM‐CSF (CSF2), IL11, CCL3, S100A8 and S100A9 were significantly decreased in gut tumours of Apc^Min/+ TLR4^−/− mice compared with Apc^Min/+ WT mice. In the functional study of core down‐regulation factors, it was found that IL6, GM‐CSF, IL11, CCL3 and S100A8/9 increased the viability of colon cancer cell lines and decreased the apoptosis rate of colon cancer cells with irradiation and chemical treatment.

Critical role of toll-like receptor 4 (TLR4) in dextran sulfate sodium (DSS)-Induced intestinal injury and repair

Ulcerative colitis² (UC) is an inflammatory bowel disease³ (IBD) that causes long-lasting inflammation and ulcers in the human digestive tract. The repair function of TLR4 in the intestinal epithelium is still unknown. Here, wild-type⁴ (WT) mice, TLR4-knockout mice⁵ (KO; TLR4^-/-) and commensal-depleted mice were used as dextran sulfate sodium⁶ (DSS)-induced or radiation-induced colitis and injury models to explore the role of TLR4 signaling in intestinal injury. Exogenous lipopolysaccharide⁷ (LPS) promoted DSS-induced inflammatory cytokines and aggravated intestinal damage. TLR4 deficiency and commensal bacterial depletion inhibited the toxic effects of LPS, but these mice were more susceptible to DSS-induced and radiation-induced intestinal damage. Compared with WT mice, neither DSS nor radiation promoted production of more inflammatory cytokines in the guts of TLR4-KO and commensal-depleted mice. Introducing the cytokine repair factors, PGE2 and GM-CSF, increased the cytokine levels in the guts of DSS-induced colitis mice. We hypothesized that TLR4 and its ligands repaired the epithelium after DSS-induced and radiation-induced intestinal damage by upregulating PGE₂ and GM-CSF. Transwell migration assays suggested that LPS, IL6, TNF, PGE₂ and GM-CSF promoted intestinal cell migration, and cell viability analysis suggested that these factors protected against radiation-induced intestinal damage. Our data underscore the importance of the balancing role of TLR4 in intestinal injury and repair.

Orphan nuclear receptor COUP-TFII is an oncogenic gene in renal cell carcinoma

BACKGROUND

Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) may be an oncogenic gene in renal cell carcinoma (RCC). However, the direct association between COUP-TFII expression and patient survival has not been investigated in patients with RCC, and the molecular oncogenesis of COUP-TFII in RCC remains unclear.

METHODS

The mRNA expression levels of COUP-TFII in the tumors of 283 patients with RCC were determined by RT-qPCR. The remaining 266 patients were categorized into low- and high-expression groups according to the cut off value generated by receiver operating curve (ROC) analysis. The function of COUP-TFII in RCC cells was tested by knockdown experiments in vitro.

RESULTS

In the present study, it was revealed that the mRNA expression levels of COUP-TFII were significantly higher in tumors compared with those in adjacent non-cancerous tissues, and that the overexpression of COUP-TFII was strongly associated with poor patient survival. It was further demonstrated that knockdown of COUP-TFII suppressed proliferation, and induced apoptosis and cell cycle arrest in RCC cells in vitro. This also resulted in the activation of the mitochondria-mediated apoptosis pathway, impaired migration and invasion of RCC cells through epithelial-mesenchymal transition in vitro, and suppressed tumor growth in vivo. In addition, it was revealed that the induction of cell migration and invasion by COUP-TFII was mediated, at least in part, by integrin subunit β1.

CONCLUSIONS

In summary, the present study indicated that COUP-TFII is an oncogenic gene in RCC, and a potential therapeutic target for the treatment of the disease.

COUP‑TFII promotes epithelial‑mesenchymal transition by inhibiting miR‑34a expression in colorectal cancer

Chicken ovalbumin upstream promoter‑transcription factor II (COUP‑TFII) expression is upregulated in colorectal cancer and is associated with its progression and a poor prognosis. The aim of the present study was to determine whether COUP‑TFII regulates colorectal cancer cell (CRC) invasion and migration by inhibiting microRNA (miR)‑34a. Transwell system and wound healing assays were performed to examine cell invasiveness and migration, respectively. Reverse transcription polymerase chain reaction and western blotting were used to detect the RNA and protein levels of target molecules, respectively. The results revealed that COUP‑TFII knockdown significantly inhibited CRC invasion and migration. In addition, the expression of miR‑34a, a well‑known tumor suppressor was revealed to be inversely correlated with COUP‑TFII expression. The miR‑34a mimic significantly reduced CRC invasion and migration abilities, while the miR‑34a inhibitor enhanced CRC invasion and migration activity. There was no significant difference between the negative small interfering RNA and miR‑34a inhibitor groups following knockdown of COUP‑TFII. Furthermore, western blotting demonstrated that miR‑34a mimics inhibited the epithelial‑mesenchymal transition (EMT) process of CRCs, while the miR‑34a inhibitor had the opposite effect. Taken together, the results demonstrate that miR‑34a regulates CRC invasion and migration by examining the mechanism by which COUP‑TFII regulates EMT.

Therapeutic effects of human monoclonal PSMA antibody-mediated TRIM24 siRNA delivery in PSMA-positive castration-resistant prostate cancer

Background and Aims: Prostate specific membrane antigen (PSMA) is specifically expressed on prostate epithelial cells and markedly overexpressed in almost all prostate cancers. TRIM24 is also up-regulated from localized prostate cancer to metastatic castration-resistant prostate cancer (CRPC). Because of the high relevance of TRIM24 for cancer development and the universal expression of PSMA in CPRC, we investigated the efficacy of human monoclonal PSMA antibody (PSMAb)-based platform for the targeted TRIM24 siRNA delivery and its therapeutic efficacy in CRPC in vivo and in vitro. Methods: The therapeutic complexes were constructed by conjugating PSMAb and sulfo-SMCC-protamine, and encapsulating TRIM24 siRNA. Flow cytometry, immunofluorescence, and fluorescence imaging were performed to detect the receptor-binding, internalization, and targeted delivery of PSMAb-sulfo-SMCC-protamine (PSP)-FAM-siRNA complex (PSPS) in vitro and in vivo. CCK-8, plate-colony formation, apoptosis, cell cycle, and Transwell assays were performed to evaluate the therapeutic potential of the PSP-TRIM24 siRNA complex in vitro, whereas the in vivo therapeutic efficacy was monitored by small animal imaging, radiography, and micro CT. Results: We confirmed that PSP could efficiently protect siRNA from enzymatic digestion, enable targeted delivery of siRNA, and internalize and release siRNA into PSMA-positive (PSMA+) prostate cancer cells in vitro and in vivo. Silencing TRIM24 expression by the PSP-TRIM24 siRNA complex could dramatically suppress proliferation, colony-formation, and invasion of PSMA+ CRPC cells in vitro, and inhibit tumor growth of PSMA+ CRPC xenografts and bone loss in PSMA+ CRPC bone metastasis model without obvious toxicity at therapeutic doses in vivo. Conclusion: PSMAb mediated TRIM24 siRNA delivery platform could significantly inhibit cell proliferation, colony-formation, and invasion in PSMA+ CRPC in vitro and suppressed tumor growth and bone loss in PSMA+ CRPC xenograft and bone metastasis model.

LncRNA NR2F2-AS1 promotes tumourigenesis through modulating BMI1 expression by targeting miR-320b in non-small cell lung cancer

Recently, long noncoding RNAs (lncRNAs) are attracting wide attention in the field of cancer research because of its important role in cancer diagnosis and prognosis. But studies on the biological effects and relevant mechanisms of lncRNAs in non‐small cell lung cancer (NSCLC) remain few and need to be enriched. Our study discussed the expression and biological effects of LncRNA NR2F2‐AS1, and further explored its possible molecular mechanisms. As a result, elevated expression of NR2F2‐AS1 was detected in NSCLC tissues and cells and was remarkably associated with the tumor, node, metastasis (TNM) stage and the status of lymphatic metastasis of patients. Down‐regulated NR2F2‐AS1 contributed to the promotion of cell apoptosis and the inhibition of cell proliferation and invasion in A549 and SPC‐A‐1 cells in vivo and vitro. Through bioinformatics analysis, NR2F2‐AS1 functions as a ceRNA directly binding to miR‐320b, BMI1 was a direct target of miR‐320b. Combined with the following cellular experiments, the data showed that NR2F2‐AS1 may influence the NSCLC cell proliferation, invasion and apoptosis through regulating miR‐320b targeting BMI1.

MicroRNA‑30a‑5p suppresses tumor cell proliferation of human renal cancer via the MTDH/PTEN/AKT pathway

The present study aimed to explore the effects of microRNA (miRNA)‑30a‑5p on tumor proliferation and to seek a potential therapeutic target for the treatment of human renal cancer. The results demonstrated that the expression levels of miRNA‑30a‑5p were reduced in tumor samples from patients with renal cancer compared with in normal tissue samples. Overall survival and disease‑free survival were increased in patients with renal cancer and high miRNA‑30a‑5p expression compared with in those with low miRNA‑30a‑5p. Furthermore, overexpression of miRNA‑30a‑5p suppressed cell proliferation, induced apoptosis, and promoted caspase‑3/9 activities and B‑cell lymphoma 2‑associated X protein (Bax) protein expression in Caki‑2 cells. In addition, the results confirmed that overexpression of miRNA‑30a‑5p inhibited metadherin (MTDH), upregulated phosphatase and tensin homolog (PTEN) and suppressed phosphorylated (p)‑protein kinase B (AKT) protein expression levels in Caki‑2 cells. Furthermore, transfection with small interfering RNA‑MTDH, increased the effects of miRNA‑30a‑5p on the inhibition of cell proliferation, and promotion of apoptosis, caspase‑3/9 activities and Bax protein expression levels in Caki‑2 cells. Knockdown of MTDH expression also upregulated PTEN and suppressed p‑AKT protein expression in Caki‑2 cells. In conclusion, the present study is the first, to the best of our knowledge, to provide evidence suggesting that miRNA‑30a‑5p suppresses tumor human renal cancer cell proliferation via the MTDH/PTEN/AKT pathway.

High expression of CREPT promotes tumor growth and is correlated with poor prognosis in colorectal cancer

CREPT (cell cycle-related and expression elevated protein in tumor) is highly expressed in many kinds of cancer, and has been shown to be prognostic in certain cancers. However, the clinical significance of CREPT in colorectal cancer (CRC) has not been sufficiently investigated. In this study, we examined the CREPT expression in 225 clinical CRC tissues and paired adjacent normal tissues, and analyzed the correlation between CREPT expression and other clinicopathological features. We also evaluated the biological function of CREPT both in vitro and in vivo using knockdown or overexpressing CRC cells. Our results showed that CREPT expressed in 175 of 225 (77.8%) CRC patients and the CREPT expression was significantly associated with tumor differentiation (P = 0.000), Dukes' stages (P = 0.013) and metastasis (P = 0.038). Patients with high CREPT expression tended to have shorter survival time. Multivariate analysis showed that positive CREPT expression can be used as an independent predictor for CRC prognosis. CREPT knockdown cells showed inhibited cell proliferation and arrested cell cycle, while CREPT overexpressing cells showed increased proliferation and promoted cell cycle. In addition, CREPT overexpression significantly promoted tumor growth in vivo. Mechanism study showed that CREPT may regulate cell proliferation and cell cycle through the regulation on cyclin D3, CDK4 and CDK6.