Circ_0000799 promotes proliferation and invasion in colorectal cancer and epithelial-mesenchymal transition.

Background: The current study aimed to investigate the effect of circ_0000799 on the biological function of colorectal cancer (CRC) cells and its mechanism. Methods: First, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was employed for detecting the expression of circ_0000799, miR-647, and miR-1243 in surgically resected specimens from hospitalized CRC patients, CRC-adjacent normal tissues (Normal group), human normal colon epithelial cells (FHC group), and CRC cell lines (HCT116, HT29, SW480, SW620). The cell proliferation, viability, and invasion were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation assay, transwell assay in HCT116 and SW480 cells with overexpression or inhibition of circ_0000799. The targeting relationship between circ_0000799 and miR-647 was verified by dual-luciferase reporter assay. The expression of epithelial-mesenchymal transition (EMT) proteins (E-cadherin, vimentin, and N-cadherin) was tested by western blot. Results: The expression level of circ_0000799 was significantly increased in CRC tissues and cells. Overexpression of circ_0000799 significantly increased cell proliferation rate, viability, invasion, and the EMT process, whereas knockdown of circ_0000799 inhibited the biological performance of CRC cells. Bioinformatic analysis suggested that miR-647 was regulated by circ_0000799, and a dual-luciferase reporter assay further showed a targeting relationship between the two. In addition, circ_0000799 was negatively correlated with miR-647 expression in CRC. Conclusions: Our findings suggest that circ_0000799 promotes proliferation and invasion in CRC and EMT. These effects of circ_0000799 may be achieved by negatively regulating miR-62.

Overexpression of Sirt6 is a novel biomarker of malignant human colon carcinoma.

Sirt family has been reported playing a significant role in the cancer development, especial its deacetylase activity plays a key function, but whether SIRT6 plays a role in mediating tumor epithelial-mesenchymal transition (EMT) and metastasis in colon cancer has not been explored. Here, the mass spectrometry and co-immunoprecipitation assays were utilized to detect that SIRT6 was physically associated with transcription factor snail. Most important, HCT116 cells transfected with SIRT6 shRNA reversed EMT, while increased the expression of TET1, and the HCT116 cells transfected with SIRT6 displayed the contrary tendency. Transwell invasion assay, soft agar assay, as well as colony formation together showed that SIRT6 promoted cell EMT and tumorigenesis in vitro. We also found SIRT6 is a reader of snail. ChIP as well as qChIP suggested H3K9 binding on the promoter of TET1 dependent on SIRT6. SIRT6 promoted EMT process through two different ways, one is as a reader of snail, and other way was the suppression of TET1 transcription. These two ways are all dependent on its H3K9 deacetylase activity. Further, patient samples collected showed that SIRT6 was significantly increased in colon cancer samples, and its higher expression was correlated with poor prognosis, worse overall survivals. Together, our experiments revealed the mechanism for SIRT6 in facilitating tumorigenesis and metastasis of colon cancer cells, suggesting that SIRT6 might be a potential therapeutic target for treating colon cancer.

Changes in patients' symptoms and gastric emptying after Helicobacter pylori treatment.

AIM: To investigate the changes in clinical symptoms and gastric emptying and their association in functional dyspepsia (FD) patients. METHODS: Seventy FD patients were enrolled and divided into 2 groups Helicobacter pylori (H. pylori)-negative group (28 patients), and H. pylori-positive group (42 patients). Patients in the H. pylori-positive group were further randomly divided into groups: H. pylori-treatment group (21 patients) and conventional treatment group (21 patients). Seventy two healthy subjects were selected as the control group. The proximal and distal stomach area was measured by ultrasound immediately after patients took the test meal, and at 20, 40, 60 and 90 min; then, gastric half-emptying time was calculated. The incidence of symptoms and gastric half-emptying time between the FD and control groups were compared. The H. pylori-negative and conventional treatment groups were given conventional treatment: domperidone 0.6 mg/(kg/d) for 1 mo. The H. pylori-treatment group was given H. pylori eradication treatment + conventional treatment: lansoprazole 30 mg once daily, clarithromycin 0.5 g twice daily and amoxicillin 1.0 g twice daily for 1 wk, then domperidone 0.6 mg/(kg/d) for 1 mo. The incidence of symptoms and gastric emptying were compared between the FD and control groups. The relationship between dyspeptic symptoms and gastric half-emptying time in the FD and control groups were analyzed. Then total symptom scores before and after treatment and gastric half-emptying time were compared among the 3 groups. RESULTS: The incidence of abdominal pain, epigastric burning sensation, abdominal distension, nausea, belching, and early satiety symptoms in the FD group were significantly higher than in the control group (50.0% vs 20.8%; 37.1% vs 12.5%; 78.6% vs 44.4%; 45.7% vs 22.2%; 52.9% vs 15.3%; 57.1% vs 19.4%; all P < 0.05). The gastric half-emptying times of the proximal end, distal end, and the whole stomach in the FD group were slower than in the control group (93.7 ± 26.2 vs 72.0 ± 14.3; 102.2 ± 26.4 vs 87.5 ± 18.2; 102.1 ± 28.6 vs 78.3 ± 14.1; all P < 0.05). Abdominal distension, belching and early satiety had an effect on distal gastric half-emptying time (P < 0.05). Abdominal distension and abdominal pain had an effect on the gastric half-emptying time of the whole stomach (P < 0.05). All were risk factors (odds ratio > 1). The total symptom score of the 3 groups after treatment was lower than before treatment (P < 0.05). Total symptom scores after treatment in the H. pylori-treatment group and H. pylori-negative group were lower than in the conventional treatment group (5.15 ± 2.27 vs 7.02 ± 3.04, 4.93 ± 3.22 vs 7.02 ± 3.04, All P < 0.05). The gastric half-emptying times of the proximal end, distal end, and the whole stomach in the H. pylori-negative and H. pylori-treatment groups were shorter than in the conventional treatment group (P < 0.05). CONCLUSION: FD patients have delayed gastric emptying. H. pylori infection treatment helps to improve symptoms of dyspepsia and is a reasonable choice for treatment in clinical practice.

Altering trend of clinical characteristics of colorectal cancer: a report of 3,607 cases.

BACKGROUND AND OBJECTIVE: Incidence of colorectal cancer in China has increased since 1980s. The epidemiologic character of colorectal cancer in China is similar to that in high prevalence districts. The distributions among different regions are different, with high incidence in the Eastern coastal regions and low incidence in the Western inland. This study was to explore the clinical characteristics of colorectal cancers in Heilongjiang province in 1981-2005. METHODS: A total of 3607 patients with pathologically confirmed colorectal cancer who were hospitalized to Tumor Hospital of Harbin Medical University, Heilongjiang province, in 1981-2005 were divided into 5-year groups. Their clinical data were analyzed. RESULTS: The annual hospitalization number of colorectal cancer patients in 1985-2005 was increased by 8.5%. The median age increased by seven years. There was no significant change in the male to female ratio of the patients. The proportion of rectal cancer decreased by 13.6%, while the proportions of both right and left hemi-colon cancers increased by 6.8%; the proportion of colorectal cancer at Dukes' A increased by 3.8%, while the proportion of colorectal cancer at Dukes' D decreased by 8.1%. CONCLUSIONS: In the past 25 years, the incidence of colorectal cancer has increased in Heilongjiang province with an increase in median age; the male to female ratio has no significant change. The incidence of rectal cancer and proportion of Dukes' A cancer have increased.