Yan Sun

Publications (2)1.84 Total impact

• Article: Depletion of PI3K p85alpha induces cell cycle arrest and apoptosis in colorectal cancer cells.

  Yan Sun, Shiyi Zhao, Hua Tian, Xiaoyun Xie, Faman Xiao, Kang Li, Yugang Song
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  ABSTRACT: Colorectal cancer is one of the most common malignancies in the world. Overactivity of phosphatidylinositol 3-kinase (PI3K) is frequently detected in colorectal carcinoma. PI3K signaling plays a pivotal role in intracellular signal transduction pathways involved in cell growth, cellular transformation, and tumorigenesis. To specifically inhibit PI3K activity in colorectal cancer cells, we constructed a siRNA against the PI3K regulatory subunit p85alpha and transfected it into LoVo and SW480 cells. In the present study, treatment of colorectal cancer cells with PI3K p85alpha-specific siRNA inhibited cell proliferation, induced G1 phase cell cycle arrest and sensitized colorectal cancer cells to 5-FU-induced apoptosis. Furthermore, depletion of PI3K p85alpha resulted in significant activation of three Forkhead box class O (FoxO) transcription factors, which inhibited the expression of cyclin D1, cdk4 and induced expression of p27/Kip1. Activation of FoxO transcription factors also increased the expression of FasL. Thus, our results indicate that siRNA-mediated gene silencing of PI3K p85alpha may be a useful therapeutic strategy for colorectal carcinoma.
  Oncology Reports 12/2009; 22(6):1435-41. · 1.84 Impact Factor
• Article: [PI3K p85alpha expression and its role in the progression of colorectal cancer].

  Yan Sun, Hua Tian, Fa-Man Xiao, Xiao-Yun Xie, Yu-Gang Song
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  ABSTRACT: To investigate the expression of PI3K p85alpha in normal colorectal tissue, colorectal adenoma and primary colorectal carcinoma and explore its significance in the progression of colorectal cancer. The expression of PI3K p85alpha was detected in 116 normal colorectal tissue, colorectal adenoma and primary colorectal carcinoma specimens using immunohistochemical staining, and the relationship between the expression of PI3K p85alpha protein and the clinicopathological factors was analyzed. The positivity rates of the expression of PI3K p85alpha protein increased gradually in the progression of colorectal cancer and showed significant differences between the tissues (P<0.05). A significant difference was also noted in the positivity rates of the PI3K p85alpha expression in colorectal carcinoma tissues at different Dukes' stages (P<0.05). No obvious correlation was found between PI3K p85alpha expression and the degree of the tumor differentiation. Abnormal PI3K p85alpha expression occurs in the progression of colorectal cancer in close relation to the clinical stage, and the PI3K/AKT pathway plays an important role in the progression of colorectal cancer.
  Nan fang yi ke da xue xue bao = Journal of Southern Medical University 04/2009; 29(3):416-8.