ABSTRACT
AIM:To investigate molecular regulatory mechanism of K-ras to girdin protein in COS7 cells and expression of K-ras and girdin in colorectal carcinoma tissues .METHODS:The lentiviral vector carrying K-ras gene was constructed and transfected in the COS 7 cells.The expression of K-ras, girdin proteins and other related proteins in COS 7 cells and colorectal carcinoma tissues was observed by Western blot .RESULTS:The COS7 cells with K-ras over-expres-sion showed an irregular cell morphology .The results of Western blot indicated that the downstream signal protein levels of p-ERK1/2, p-Stat3 and girdin were significantly increased in the COS 7 cells with K-ras over-expression.Transfection with the K-ras siRNA into the COS7 cells significantly reduced the protein levels of p-ERK1/2, p-Stat3 and girdin.In the color-ectal carcinoma tissues (7 cases), 5 cases had higher expression of K-ras and girdin compared with pericarcinous tissues . CONCLUSION:K-ras regulates girdin expression through the signal pathway of K-ras-ERK1/2-Stat3-girdin.
ABSTRACT
Objective To investigate the expression of girders of actin filaments (Girdin) in pituitary adenomas, and its role in promoting cell proliferation and the related molecular mechanism. Methods Two prolactinoma, growth hormone adenoma and non-functioning pituitary adenoma tissues, and one normal pituitary gland tissue were collected. The protein expression of Girdin in the different tissues was detected by Western blotting, and then the expression of Girdin was further confirmed by immunofluorescence. Rat pituitary tumor cell lines GH3 cell model with Girdin knockdown and overexpression was established by RNA interference and overexpression of Girdin, respectively. The protein expression of Girdin and Akt and phosphorylation level of Akt in the GH3 cell models were detected by Western blotting. The function and biological behavior of Girdin in pituitary adenomas tissues were studied by cell proliferation assay and cell apoptosis assay. Results The expression of Girdin in the non-functioning pituitary adenomas was the highest, followed by growth hormone pituitary adenomas. The high expression of Girdin in the non-functioning pituitary adenomas was also verified by immunofluorescence assay. RNA interference and overexpression of Girdin effectively knocked down and increased the expression of Girdin, respectively, accompanied by the simultaneous changes of Akt phosphorylation. In addition, overexpression of Girdin promoted the proliferation of GH3 cells. Conclusion Girdin is highly expressed in non-functioning pituitary adenomas and can promote the proliferation of pituitary adenoma cell by regulating the Akt phosphorylation.
ABSTRACT
Girdin protein is a kind of actin binding protein,which has the complex molecular structure and takes part in a variety of signaling pathways related with causing cancer.The biological characteristics of Gir-din protein have close association with the proliferation and invasion of malignant tumor.Recent studies have shown that Girdin protein is closely related with occurrence and progress of breast cancer.Girdin protein expres-sion in breast cancer cells can not only promote the progress of breast cancer,but also affect the lymph node me-tastasis and prognosis.Therefore Girdin protein is expected as an independent biomarker to provide a new direc-tion for breast cancer treatment.
ABSTRACT
The purpose of this study is to reveal the role of Girdin in regulating the aggregation of actin filaments by studying the relationship between PKB/Akt and Girdin. First we used Scansite software (http://scansite.mit.edu) to predict relevant target sites of PKB/Akt on mouse Girdin. To gain insight into the role of phosphorylation of Girdin by PKB/Akt, we assessed the location of phosphorylated Girdin in fertilized eggs by staining with anti-P-Girdin 1 417 Ab. We detected a distinct increase in the fluorescence signal of F-actin and P-Girdin 1 417 after microinjection of Akt WT and myr-Akt. The addition of myr-Akt induced phosphorylation of Girdin in mouse fertilized eggs. In addition, siRNA-mediated Akt-knockdown blocked phosphorylation of Girdin. The distribution of actin filaments was obviously scattered. These results strongly suggest that PKB/Akt could directly phosphorylate Girdin on Ser1 417 and promote its function in mouse fertilized eggs.