Upregulation of LncDQ is Associated with Poor Prognosis and Promotes Tumor Progression via Epigenetic Regulation of the EMT Pathway in HCC.

BACKGROUND/AIMS: Long noncoding RNAs (lncRNAs) are key regulators of cancer initiation and progression. In this study, we investigated the clinical value and functional role of LncRNA DQ786243 (LncDQ) in the pathogenesis of hepatocellular carcinoma (HCC). METHODS: To investigate the expression level of LncDQ in HCC, we performed quantitative real-time PCR using total RNA extracted from HCC tumor tissues and their matched non-neoplastic counterparts, as well as from the serum of HCC patients and healthy volunteers. The correlation of LncDQ expression with clinicopathologic features and prognosis was analyzed. The functional role of LncDQ in cell proliferation, migration, and invasion were evaluated by MTT cell viability, wound healing, and transwell assays in vitro and in vivo. RNA immunoprecipitation and chromatin immunoprecipitation assays were performed to analyze the potential mechanism of LncDQ in HCC cells. RESULTS: LncDQ was upregulated in both HCC tissue samples and serum and was correlated with low survival rate and adverse clinical pathological characteristics. Multivariate analysis demonstrated that LncDQ expression was an independent prognostic factor for HCC. The area under the receiver operating characteristic curve was 0.804 with a sensitivity of 0.72 and a specificity of 0.8. Knockdown of LncDQ induced inhibition of cell proliferation, migration, and invasion in vitro and in vivo. Mechanistically, LncDQ regulated the epithelial-mesenchymal transition pathway by interacting with EZH2, to epigenetically repress the expression of E-cadherin in HCC cells. CONCLUSIONS: Taken together, the results of our study indicate that LncDQ plays a critical role in HCC progression, and may serve as a potential diagnostic and prognostic biomarker for HCC.

[Effect of ASCT2 gene knock-down by shRNA on biological behaviors of colorectal cancer cells].

OBJECTIVE: To investigate the effect of ASCT2 gene (glutamine transporter) knock-down by shRNA on biological behaviors of colorectal cancer cells. METHODS: shRNA was transfected into colorectal cancer cells Lovo and SW480 to knockdown ASCT2 mediated by Lipofectamine 2000. Reverse transcription-PCR and Western blot were used to examine the mRNA and protein expression of ASCT2. MTT and transwell assay were used to determine the proliferation and invasiveness of Lovo and SW480 cells. Radioactive-tracer was used to detect the uptake of glutamine. RESULTS: ASCT2 mRNA and protein levels were significantly down-regulated by shRNA in Lovo and SW480 cells(P<0.01). MTT and transwell assays showed that ASCT2 knock-down could significantly inhibit the proliferation of Lovo and SW480 cells (A490) and decrease the number of invasive Lovo and SW480 cells from the membrane (both P<0.01). The number of membrane Lovo cells in shASCT group and control group was 46.3±5.9 and 197.7±9.1, respectively while the number of membrane SW480 cells in shASCT group and control group was 29.7±3.8 and 139.0±9.5, respectively. Radioactive-tracer showed that shASCT2 transfection could significantly reduce the uptake of glutamine, with an inhibition rate of 79.15% in Lovo and 67.22% in SW480 cells (both P<0.01). CONCLUSIONS: ASCT2 plays an oncogenic role in colonic cancer, and its promotion mechanism may be associated with glutamine metabolism. ASCT2 may be a novel therapeutic target of colonic cancer.

LncRNA TUG1 sponges miR-145 to promote cancer progression and regulate glutamine metabolism via Sirt3/GDH axis.

Long noncoding RNAs (lncRNAs) are important regulators in cancer progression. Deregulation of the lncRNA taurine upregulated gene 1 (TUG1) predicts poor prognosis and is implicated in the development of several cancers. In this study, we investigated the role of TUG1 in the pathogenesis of intrahepatic cholangiocarcinoma (ICC). We found that TUG1 is upregulated in ICC samples, which correlates with poor prognosis and adverse clinical pathological characteristics. Knockdown of TUG1 inhibited the proliferation, motility, and invasiveness of cultured ICC cells, and decreased tumor burden in a xenograft mouse model. When we explored the mechanisms underlying these effects, we found that TUG1 acts as an endogenous competing RNA (ceRNA) that 'sponges' miR-145, thereby preventing the degradation of Sirt3 mRNA and increasing expression of Sirt3 and GDH proteins. Accordingly, glutamine consumption, α-KG production, and ATP levels were dramatically decreased by TUG1 knockdown in ICC cells, and this effect was reversed by miR-145 inhibition. These findings indicate that the TUG1/miR-145/Sirt3/GDH regulatory network may provide a novel therapeutic strategy for treatment of ICC.

[Oncologic safety of laparoscopic surgery in radical resection for different stage rectal cancer].

OBJECTIVE: To evaluate the oncologic safety and short-term outcomes of laparoscopic surgery in early and advanced rectal cancers. METHODS: Clinical and follow-up data of 186 cases with rectal cancer undergoing laparoscopic radical resection from June 2009 to December 2013 were analyzed retrospectively, including 48 early rectal cancer (stage 0-I) and 138 advanced cancer (stage II-III). Thirty-seven cases with early rectal cancer and 275 with advanced cancer undergoing open radical surgery were selected as control group. Surgical safety, oncologic safety and short-term outcomes were compared between two groups. RESULTS: As for either early or advanced rectal cancer, there were no significant differences in the number of harvested lymph nodes, length of distal resection margin, complication morbidity, rate of local recurrence, distant metastasis, and 3-year survival rate between the two groups (all P>0.05). Although the operation time was longer in laparoscopic group, the laparoscopic group presented less intra-operative blood loss, faster recovery of bowel function, and shorter postoperative hospital stay (all P<0.05). As for advanced rectal cancer, laparoscopic radical surgery tended to achieve less lymph nodes dissected (mean, 13.5 vs. 15.0) and develop more anastomotic leakage (8.0% vs. 5.5%) compared to open surgery, although neither reached statistical significance (P=0.112, P=0.221). Moreover, the conversion rate in patients with advanced rectal cancer was significantly higher than that in those with early cancer (10.9% vs 2.1%, P=0.048). CONCLUSIONS: Laparoscopic surgery can obtain the same oncologic and surgical safety for early rectal cancer as compared to open surgery. However, due to higher conversion rate, potential risk of decreased number of harvested lymph nodes and increased anastomotic leakage, laparoscopic surgery for advanced rectal cancer should be carried out prudently, especially in some hospitals with less laparoscopic experience.

Glutamate dehydrogenase is a novel prognostic marker and predicts metastases in colorectal cancer patients.

BACKGROUND: Glutamate dehydrogenase (GDH) is a key enzyme that catalyzes the final reaction of the glutamine metabolic pathway, and has been reported implicated in tumor growth and metastasis. However, it's clinical significance and role in colorectal cancer (CRC) pathogenesis is largely unknown. METHODS: The expression of GDH was determined by qPCR, western blot and immunohistochemistry in CRC cells and samples. The correlation of GDH expression with clinicopathologic features and prognosis was analyzed. The functional role of GDH in CRC cell proliferation, motility and metastasis was evaluated. RESULTS: We found that GDH was up-regulated both in colorectal cancer and metastatic lesions (n = 104). Patients with high GDH expression had poorer overall survival (HR 2.32; 95% CI 1.26-4.26; P = 0.007) and poorer disease-free survival rates (HR 2.48; 95% CI 1.25-4.92; P = 0.009) than those with low GDH expression. Furthermore, we showed that GDH expression was an independent prognostic factor for CRC. In addition, over-expression of GDH promoted cell proliferation, migration and invasion in vitro, whereas loss function of GDH did the opposite. Finally, we demonstrated that the promotion of CRC progression by GDH correlated with activation of STAT3 mediated epithelial-mesenchymal transition (EMT) induction. CONCLUSIONS: These results indicate that GDH plays a critical role in CRC progression, and may provide a novel metabolism therapeutic target for CRC treatment.