Herein lie the crosstalk and regulation between AQP1 and Emmprin in SMMC7221 cells by means of siRNA technology and deglycosylation method. Firstly, HAQP1, rather than hAQP3, was selectively upregulated in SMMC7221 cells by FBS, flollowed by the upregulated expression of Emmprin. Emmprin gene silencing caused a remarkable change in the expression ofAQP1 gene, just like its downstream gene, MMP9, meanwhile the water permeability and cell migration were also descended prominently. Furthermore, when treated with tunicamycin, Emmprin was deglycosylated, which made the expression of AQP 1 significantly declined, followed by remarkably decreased cell membrane water permeability and cell migration. Taken together, all the data indicates the expression level and the modification of Emmprin by glycosylation are the key factors in regulating the expression of AQP1.
LI JiangZHANG Ai-liTONG QianZHANG Jun-fangLI Hai-jingZHAO BingMA Tong-huiLI Xiao-men
Aim： To investigate possible correlation factors for prostate cancer by a population-based case-control study in China. Methods： We carded out a mass screening of prostate cancer in Changchun, China, using a prostate-specific antigen assisted by Japan International Cooperation Agency. From June 1998 to December 2000, 3 940 men over 50 years old were screened. Of these, 29 men were diagnosed with prostate cancer. We selected 28 cases and matched them with controls of low prostate-specific antigen value （〈 4.1 ng/mL） by 1：10 according to age and place of employment. A case-control study of diet and prostate cancer was then carded out. Results： After adjustment for education, body mass index （BMI）, smoking, alcohol consumption, marriage and diet, intake of soybean product was discovered to be inversely related to prostate cancer. Men who consumed soybean product more than twice per week on different days had a multivariate odds ratio （OR） of 0.38 （95% confidence interval [CI], 0.13-1.12）. In addition, men who consumed soybean products more than once per day had a multivariate OR of 0.29 （95% CI, 0.11-0.79） compared with men who consumed soybean products less than once per week. The P for trend was 0.02, which showed significant difference. There was no significant difference in P trend for any dairy food. Even when we matched the cases and controls by other criteria, we found that soybean food was the only preventive factor associated with prostate cancer. Conclusion： Our study suggests that consumption of soybeans, one of the most popular foods in Asia, would decrease the risk of prostate cancer.
The authors investigated the regulation of human aquaporin I（hAQP1） and the involvement of aquaporin 1 （AQP 1） in the migration of human hepatocellular carcinoma SMMC-7221 cells using RNA intereference technology Firstly, two short hairpin RNA（shRNA） constructs in PBSU6 vector were reconstructed and their knockdown effects were identified in SMMC-7221 cells. Next, the involvement of endogenous hAQP1 in regulating the migration of SMMC-7221 cells was investigated via siRNA technology. HAQPI-shRNA can specifically inhibit AQP1 dependent osmotic water permeability. Meanwhile the migration of SMMC-7221 cells was inhibited remarkably after silencing AQP1 by performing transwell cell migration assay and in vitro wound healing assay. Furthermore, in the presence of an inhibitor HgCl2, the water permeability of the cell membrane was remarkably decreased, the expression of AQP1 was upregulated after HgCla treatment and the cell movement was decreased at the moment. Increased AQP1 cannot attenuate cell migration ability when cell membrane loses its water permeability function. This demonstrates that the cell migration was remarkably related to the transporting water function of cell membrane.
