title: Lymphangiogenesis in gastric cancer regulated through Akt/mTOR-VEGF-C/VEGF-D axis.
abstract: BACKGROUND
  Lymphangiogenesis plays a significant role in metastasis and recurrence of gastric cancer. There is no report yet focusing on the modulation of VEGF pathway and lymphangiogenesis of gastric cancer by targeting Akt/mTOR pathway. This study aims to demonstrate the relationship between Akt/mTOR pathway and VEGF-C/-D in gastric cancer.
  
  
  METHODS
  We collected surgically resected gastric adenocarcinoma specimens from 55 consented patients. Immunohistochemistry staining of p-Akt, p-mTOR, VEGF-C, VEGF-D were performed and scored by two independent pathologists. The results were presented as staining intensity and positive staining cell rate. We also measured lymphatic vessel density (LVD) by D2-40 staining. Different dosages of p-Akt inhibitor LY294002 (12.5 μM, 25 μM, 50 μM) and p-mTOR inhibitor Rapamycin (25 nM, 50 nM, 100 nM) were given to gastric cancer cell line SGC-7901 in vitro. The inhibition rate of cell growth was tested by MTT at 24 h, 48 h and 72 h, respectively and protein expressions of Akt, p-Akt, mTOR, p-mTOR, VEGF-C and VEGF-D were examined by Western blot.
  
  
  RESULTS
  The positive staining rates of p-Akt, p-mTOR, VEGF-C and VEGF-D in 55 gastric cancer clinical specimens were 74.54%, 85.45%, 72.73% and 58.18%. p-Akt and p-mTOR were positively correlated with VEGF-C and VEGF-D (p < 0.01). The LVD increased with incremental tendency of staining intensity of p-Akt, p-mTOR, VEGF-C and VEGF-D. LY294002 or Rapamycin significantly suppressed SGC-7901 cell growth and the inhibition rate was dose and time dependent (p < 0.001). In addition, the protein expression of p-Akt and p-mTOR were positively correlated with that of VEGF-C and VEGF-D (p < 0.05).
  
  
  CONCLUSIONS
  The level of LVD in gastric cancer specimens was significant higher than that of normal gastric tissue and was positively correlated with p-Akt, p-mTOR, VEGF-C and VEGF-D. Inhibition of p-Akt and p-mTOR, in vitro, decreased tumor cell VEGF-C and VEGF-D significantly. Therefore, we concluded that lymphangiogenesis of gastric cancer might be related to Akt/mTOR-VEGF-C/VEGF-D axis.
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, 17 Yongwaizheng Street, Nanchang, 330006, China. yfychx@163.com.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology, Kaiping Central Hospital, Kaiping, 529300, China. kingpnin@163.com.
authors.forename: Runnian
authors.initials: R
authors.lastname: Guan
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, 17 Yongwaizheng Street, Nanchang, 330006, China. zg_lyp@163.com.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Lei
authors.affiliation: Department of Gastroenterology, Jiangxi Provincial People's Hospital, Nanchang, 330006, China. cjyacy69@163.com.
authors.forename: Jianyong
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, 17 Yongwaizheng Street, Nanchang, 330006, China. 15979044325@163.com.
authors.forename: Qi
authors.initials: Q
authors.lastname: Ge
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. beakham13@126.com.
authors.forename: Xiaoshen
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. douruoxu@gmail.com.
authors.forename: Ruoxu
authors.initials: R
authors.lastname: Dou
authors.affiliation: Department of Pathogen Biology and Immunology, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, 510060, China. hychen1208@126.com.
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. proliuhao@gmail.com.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, 17 Yongwaizheng Street, Nanchang, 330006, China. qixiaolongmd@gmail.com.|Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. qixiaolongmd@gmail.com.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Qi
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, 17 Yongwaizheng Street, Nanchang, 330006, China. yfyzxd@163.com.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, 17 Yongwaizheng Street, Nanchang, 330006, China. c.changyan@neu.edu.|Center for Drug Discovery, Northeastern University, Boston, MA, 02115, USA. c.changyan@neu.edu.
authors.forename: Changyan
authors.initials: C
authors.lastname: Chen
mesh_terms: D014408:Biomarkers, Tumor; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D042582:Vascular Endothelial Growth Factor C / Q000378:metabolism*; D042643:Vascular Endothelial Growth Factor D / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D002867:Chromones; D004791:Enzyme Inhibitors; D009025:Morpholines; D042582:Vascular Endothelial Growth Factor C; D042643:Vascular Endothelial Growth Factor D; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases