Yueming Sun

Genetic and epigenetic alterations are involved in the regulation of TPM1 in cholangiocarcinoma.

Cholangiocarcinoma is a malignant tumor originating from biliary epithelial cells. The tumor suppressor gene tropomyosin 1 (TPM1) is downregulated in several human cancer types; however, its expression status in cholangiocarcinoma is still unknown. We elucidated TPM1 expression and its regulation mechanism in cholangiocarcinoma. Real-time (RT)-PCR, western blot analysis and immunohistochemistry were performed to examine TPM1 expression levels in cholangiocarcinoma cell lines and tumor tissues. Cell lines were treated with lentiviral vector containing the miR-21 knockdown and inhibitors of genetic and epigenetic mechanisms (manumycin A, LY294002, U0126, DAC and TSA), and the TPM1 expression change was observed by RT-PCR and western blot analyses. Cell proliferation, apoptosis and migration were evaluated by water-soluble tetrazolium salt (WST-1) assay, flow cytometry and wound healing experiments, respectively. TPM1 was downregulated in the intrahepatic cholangiocarcinoma cells (HuCCT1) and upregulated in the extrahepatic cholangiocarcinoma cells (QBC939) compared with normal intrahepatic biliary epithelial cells (HIBEC). TPM1 stained negative in the intrahepatic cholangiocarcinoma tissues, as revealed by immunohistochemistry, although there was no significant difference in staining of the intrahepatic cholangiocarcinoma tissues and adjacent non-cancer tissues. RAS and two important downstream signaling pathways (RAS/PI3K/AKT and RAS/MEK/ERK) were involved in TPM1 regulation and inhibition of the epigenetic mechanisms such as DNA methylation, histone deacetylation and miR-21 upregulation upregulated TPM1 expression. Inhibitors of genetic and epigenetic mechanisms (manumycin A, LY294002, U0126, DAC and TSA) inhibited cell proliferation and migration and induced apoptosis. These data indicated that TPM1 is downregulated in HuCCT1 cells and that the Ras signaling pathway as well as DNA methylation, histone deacetylation and miR-21 upregulation play important roles in the suppression of TPM1 expression in HuCCT1 cells. Thus, compounds that inhibit genetic and epigenetic mechanisms may be promising agents in treating cholangiocarcinoma.

TRIM27 functions as an oncogene by activating epithelial-mesenchymal transition and p-AKT in colorectal cancer

Tripartite motif-containing 27 (TRIM27) belongs to the tripartite motif (TRIM) protein family and is involved in various malignant tumor processes. However, the function and mechanism of TRIM27 in colorectal cancer (CRC) remains to be elucidated. In the present study, the expression of TRIM27 was analyzed in CRC tissues and adjacent normal tissues by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. LoVo and HCT116 cell lines were then selected to further investigate the function of TRIM27 in the proliferation, invasion and metastasis of CRC in vitro and in vivo. Finally, the potential mechanism underlying the effects of TRIM27 in CRC was examined by western blotting. The results showed that TRIM27 was upregulated in CRC tissues, and the expression level of TRIM27 was significantly associated with tumor invasion, metastasis and prognosis. Following TRIM27 inhibition and overexpression in CRC cells, it was found that TRIM27 promoted cell proliferation, possibly via the inhibition of apoptosis and cell cycle regulation. TRIM27 also facilitated invasion and metastasis. Finally, it was observed that TRIM27 promoted epithelial-mesenchymal transition and activated phosphorylated AKT serine/threonine kinase in CRC cells. These results suggested that TRIM27 is an oncogenic protein in the progression of CRC, and may represent a novel target for CRC detection and therapy.

Clinical application of endoscopic thyroidectomy via an anterior chest wall approach.

Background: Endoscopic minimally invasive surgery of the cervical region is currently used to treat benign thyroid disease. The aim of this study was to evaluate the safety, feasibility, and inflammatory response to endoscopic thyroidectomy (ET) via an anterior chest wall approach. Methods: Between January 2007 and January 2012, 320 patients underwent sub-total/total thyroidectomy. Of these, 160 had endoscopic surgery through an anterior chest wall approach (ET, group A) and 160 had traditional open surgery (group B). Demographics, operation time, intraoperative blood loss, complications, hospital stay, cost, and postoperative outcomes were compared between the 2 groups. Serum Interleukin-6 and C-reactive protein levels were measured preoperatively and at 2, 12, 24, and 48 hours postoperatively. Results: Patient demographics, tumor size, operation time, and pathologic diagnoses were similar in both groups. There was no difference in procedure time and postoperative complication rates. Intraoperative blood loss and length of hospital stay were significantly lower in group A (P<0.05), but cost was higher (P<0.05). Serum Interleukin-6 and C-reactive protein levels increased significantly after both procedures, with levels at the 24-hour and 48-hour time points higher in group B (P<0.05). Two cases in group A and 1 in group B developed a transient hoarse voice postoperatively, which recovered 7.5 days (range, 5 to 12 d) later. There were no serious complications during the 2-year follow-up. Conclusions: ET through an anterior chest wall approach is safe and feasible for benign thyroid disease, and offers the advantage of no visible scar.

GPR56 promotes proliferation of colorectal cancer cells and enhances metastasis via epithelial‑mesenchymal transition through PI3K/AKT signaling activation

G protein-coupled receptor 56 (GPR56), a member of the orphan GPCR family, has been reported to be an oncogene in various malignancies. However, little is known regarding the detailed molecular mechanism of GPR56 in colorectal cancer (CRC). The present study aimed to detect the expression level and biological function of GPR56 in CRC. We examined the expression of GPR56 in CRC tissues and cell lines by quantitative real time (qRT)-PCR, immunohistochemistry, and western blot analysis. The prognostic significance of GPR56 in CRC patients was evaluated by Kaplan-Meier survival analysis. The influence of GPR56 on tumor cell proliferation (via Cell Counting Kit-8, and a tumor formation assay in mice), apoptosis (flow cytometry), cell cycle distribution (flow cytometry) and migration (Transwell assay) was explored. We also investigated the underlying mechanism of GPR56 by western blot analysis. We found GPR56 expression was significantly upregulated in CRC tissues and cell lines compared to corresponding normal controls. Higher GPR56 expression in patients predicted poorer prognosis. Depletion of GPR56 markedly suppressed cell proliferation, migration, and invasion. GPR56 overexpression promoted CRC cell metastasis by expediting epithelial-mesenchymal transition by activating PI3K/AKT signaling. In conclusion, GPR56 played an important role in CRC progression and may represent a new therapeutic target to reduce CRC metastasis.

Construction of a ceRNA network reveals potential lncRNA biomarkers in rectal adenocarcinoma

Competing endogenous RNAs (ceRNAs) render the functions of long non-coding RNAs (lncRNAs) more complicated during cancer processes. Potential lncRNA biomarkers and their roles as ceRNAs have not been clearly described for rectal adenocarcinoma (READ). In the present study, we extracted data from The Cancer Genome Atlas (TCGA) including data from 167 tumor samples and 10 adjacent non-tumor samples. A total of 202 lncRNAs, 190 microRNAs (miRNAs) and 1,530 mRNAs were identified as READ-specific RNAs [log2(fold-change)>2, FDR<0.01]. The Gene Ontology (GO) biological processes and the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways were analysed for 1,530 specific mRNAs. Among 202 READ-specific lncRNAs, 7 lncRNAs were identified as being associated with overall survival of READ patients. Then, a ceRNA network was constructed with 34 key lncRNAs, 25 miRNAs and 65 mRNAs. A total of 7 lncRNAs from the network were revealed to be linked to clinical features. The results of qRT-PCR ascertained that our analysis was credible. Overall, this research provides a novel perspective from which to study the lncRNA-related ceRNA network in READ and assists in the identification of new potential biomarkers to be used for diagnostic and prognostic purposes.

CDCA3 mediates p21-dependent proliferation by regulating E2F1 expression in colorectal cancer

Dysregulated cell cycle progression serves a crucial role in tumor development. Cell division cycle- associated 3 (CDCA3) is considered a trigger of mitotic entry; it is an important part of the S phase kinase-associated protein 1/Cullin/F-box ubiquitin ligase complex and mediates the destruction of mitosis-inhibitory kinase wee1. However, little is known about the role of CDCA3 in cancer, particularly colorectal cancer (CRC). The present study aimed to explore the biological and clinical significance of CDCA3 in CRC growth and progression. CDCA3 expression was significantly associated with tumor progression and poor survival. Overexpression of CDCA3 increased proliferation in LoVo CRC cells, whereas CDCA3 knockdown in SW480 CRC cells led to decreased proliferation, in vitro and in vivo. Further mechanistic investigations demonstrated that reduced CDCA3 expression resulted in G1/S phase transition arrest, which was attributed to a significant accumulation of p21 in SW480 cells; conversely, increased CDCA3 expression promoted G1/S phase transition through decreased p21 accumulation in LoVo cells. It was also demonstrated that CDCA3 was able to regulate the expression of transcription factor E2F1, thereby repressing p21 expression. Taken together, these results suggested that overexpression of CDCA3 may serve a crucial role in tumor malignant potential and that CDCA3 may be used as a prognostic factor and a potential therapeutic target in CRC.

Analysis of lncRNA-Associated ceRNA Network Reveals Potential lncRNA Biomarkers in Human Colon Adenocarcinoma

Background/Aims: Long non-coding RNAs (lncRNAs) acting as competing endogenous RNAs (ceRNAs) play significant roles in the development of tumors, but the functions of specific lncRNAs and lncRNA-related ceRNA networks have not been fully elucidated for colon adenocarcinoma (COAD). In this study, we aimed to clarify the lncRNA-microRNA (miRNA)-mRNA ceRNA network and potential lncRNA biomarkers in COAD. Methods: We extracted data from The Cancer Genome Atlas (TCGA) and identified COAD-specific mRNAs, miRNAs, and lncRNAs. The biological processes in Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were analyzed for COAD-specific mRNAs. We then constructed a ceRNA network of COAD-specific mRNAs, miRNAs and lncRNAs and analyzed the correlation between expression patterns and clinical features of the lncRNAs involved. After identifying potential mRNA targets of 4 lncRNAs related to overall survival (OS), we conducted stepwise analysis of these targets through GO and KEGG. Using tissue samples from our own patients, we also verified certain analytical results using quantitative real-time PCR (qRT-PCR). Results: Data from 521 samples (480 tumor tissue and 41 adjacent non-tumor tissue samples) were extracted from TCGA. A total of 258 specific lncRNAs, 206 specific miRNAs, and 1467 specific mRNAs were identified (absolute log2 [fold change] > 2, false discovery rate < 0.01). Analysis of KEGG revealed that specific mRNAs were enriched in cancer-related pathways. The ceRNA network was constructed with 64 lncRNAs, 18 miRNAs, and 42 mRNAs. Among these lncRNAs involved in the network, 3 lncRNAs (LINC00355, HULC, and IGF2-AS) were confirmed to be associated with certain clinical features and 4 lncRNAs (HOTAIR, LINC00355, KCNQ1OT1, and TSSC1-IT1) were found to be negatively linked to OS (log-rank p < 0.05). KEGG showed that the potential mRNA targets of these 4 lncRNAs may be concentrated in the MAPK pathway. Certain results were validated by qRT-PCR. Conclusion: This study providing novel insights into the lncRNA-miRNA-mRNA ceRNA network and reveals potential lncRNA biomarkers in COAD.

Upregulated miR-1258 regulates cell cycle and inhibits cell proliferation by directly targeting E2F8 in CRC

MicroRNAs (miRNAs) as small noncoding RNA molecules function by regulating their target genes negatively. MiR‐1258 was widely researched in multicancers, but its role remains unclear in colorectal cancer (CRC).