Leucine-rich repeat-containing G-protein-coupled receptor 5 is associated with invasion, metastasis, and could be a potential therapeutic target in human gastric cancer.

BACKGROUND: Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5), which is identified as a novel intestinal stem cell marker, is overexpressed in various tumours. In this study, we explore Lgr5 expression in gastric carcinoma and analyse its role in invasion, metastasis, and prognosis in carcinoma. METHODS: A combination of immunohistochemistry, western blotting, and quantitative reverse transcription-polymerase chain reaction were used to detect mRNA and protein expression levels of Lgr5 and matrix metalloproteinase 2 (MMP2). Small interfering RNA against Lgr5 was designed, synthesised, and transfected into AGS cells. The effects of Lgr5 siRNA on cell invasion were detected by transwell invasion chamber assay and wound healing assay. RESULTS: Leucine-rich repeat-containing G-protein-coupled receptor 5 expression was significantly higher in gastric carcinomas than in normal mucosa. Leucine-rich repeat-containing G-protein-coupled receptor 5 expression positively correlated with the depth of invasion, lymph node metastasis, distance of metastasis, and MMP2 expression levels. Multivariate analysis showed that Lgr5 had an independent effect on survival, and that it positively correlated with MMP2. Leucine-rich repeat-containing G-protein-coupled receptor 5 siRNAs inhibited Lgr5 mRNA and protein expression. Transwell assays indicated that these siRNAs resulted in significantly fewer cells migrating through the polycarbonate membrane, and wound healing assay also indicated that siRNAs decreased the migration of cells. Inhibition of Lgr5 resulted in a significant decrease in MMP2 and ß-catenin levels compared with those in controls. CONCLUSIONS: Leucine-rich repeat-containing G-protein-coupled receptor 5 was correlated with invasion and metastasis. Leucine-rich repeat-containing G-protein-coupled receptor 5 inhibition could serve as a novel therapeutic approach.

[Surgical selection and metastatic warning of splenic lymph node dissection in advanced gastric cancer radical surgery: a prospective, single-center, randomized controlled trial].

Objective: To investigate the surgical options for splenic lymph node dissection in patients with advanced gastric cancer undergoing radical total gastrectomy, and to evaluate the sentinel effect of No. 4s lymph node on splenic lymph node metastasis. Methods: A prospective, single-center, randomized and controlled study was carried out (Trial registration, No.NCT02980861). Enrollment criteria: (1) >18 years old and <65 years old; (2) gastric adenocarcinoma locating in the proximal or corpus; (3) preoperative clinical staging as cT2-4aN0-3M0; (4) D2 radical total gastrectomy feasible judged before operation; (5) physical ability score 0 to 1; (6) I to III of ASA classification. Pregnant or lactating women, patients with severe mental illness or previous history of upper abdominal surgery, those suffered from other malignant tumors in the past 5 years, or heart and lung system diseases judged to affect surgery before operation, those receiving preoperative chemotherapy, radiotherapy or targeted therapies, and distant metastases being found during surgery were excluded. According to above criteria, 222 patients at The First Medical Center of Chinese PLA General Hospital from December 2016 to December 2017 were enrolled prospectively and were randomly divided into the laparoscopic splenic hilar lymph node dissection group (laparoscopic group, n=114) and the open splenic hilar lymph node dissection group (open group, n=108). The result of rapid frozen immunohistochemistry of harvested No.4s lymph nodes was used to evaluate the sensitivity and specificity of sentinel effect on splenic hilar lymph node metastasis. The surgical parameters, postoperative recovery parameters, and complication rates were compared between the two groups. Results: There were 80 males and 34 females in the lapascopic group with a mean age of (56.1±10.2) years, and 69 males and 39 females in the open group with a mean age of (58.4±10.9) years. There were no significant differences in baseline data between the two groups (all P>0.05). Total blood loss was less in the laparoscopic group [(96.3±82.4) ml vs. (116.6±101.9) ml, t=1.124, P<0.001], and the amount of bleeding from the splenic hilar lymph nodes dissected was also less than that in the open group [(25.3±17.8) ml vs. (59.5±36.4) ml, t=1.172, P<0.001]. However, the operation time, the time of splenic hilar lymph node, the number of lymph node dissected and number of splenic hilar lymph node dissected were not significantly different between the two groups (all P>0.05). As compared to the open group, the laparoscopic group had shorter time to the first flatus [(1.3±1.2) days vs. (1.6±1.5) days, t=1.665, P=0.021], shorter time to fluid diet [(4.6±1.4) days vs. (4.9 ± 1.6) days, t=1.436, P=0.007], shorter time to remove nasogastric tube [(3.9±2.6) days vs. (4.3±2.4) days, t=0.687, P<0.001] and shorter hospital stay [(10.3±6.6) days vs. (12.1±7.2) days, t=0.697, P<0.001]. Complication rate was 14.0% (16/114) and (12.0%) ((1)3/108) in the laparoscopic group and the open group, respectively, without significant difference (χ(2)=6.723, P=0.331). The sensitivity of the No. 4s lymph node for the prediction of splenic hilar lymph node metastasis reached 89.5%, and the specificity reached 99.6%. Conclusions: Laparoscopic technique is safe and feasible in the treatment of splenic hilar lymph node dissection in advanced gastric cancer. The No.4s lymph node examination has good sentinel effect on predicting the metastasis of splenic hilar lymph nodes.