Low heme oxygenase-1 expression promotes gastric cancer cell apoptosis, inhibits proliferation and invasion, and correlates with increased overall survival in gastric cancer patients.

Heme oxygenase-1 (HO-1) plays a key role in anti-oxidation, anti-apoptosis, and anti-proliferation in various types of cancers. However, the relationship between HO-1 expression and gastric cancer development remains largely unknown. In this study, the protein expression of HO-1 in human gastric cancer was measured by immunohistochemistry on paraffin sections of 89 paired gastric carcinoma tissues and adjacent non-cancer tissues. The correlation of HO-1 expression with 5-year overall survival rate was estimated. The effects of decreased HO-1 expression by two strands of small interfered RNAs (siRNAs) on cell apoptosis, proliferation, and invasion of gastric cancer cell lines were examined by flow cytometry, the MTT assay, and the cell migration assay, respectively. High expression of HO-1 was detected in 11.2% (10/89) of gastric carcinoma tissues, compared with 1.1% (1/89) in matched adjacent normal tissues, and correlated with a decreased survival rate in gastric cancer patients. There were no significant correlations between HO-1 expression and clinical characteristics. Downregulation of HO-1 expression using two strands of siRNAs promoted apoptosis and inhibited the proliferation and invasion of two gastric cancer cell lines, SGC7901 and MKN-28 cells. This study demonstrated that HO-1 plays a vital role in the development of gastric cancer and may serve as a therapeutic target of this type of cancer.

Regulatory effects of deguelin on proliferation and cell cycle of Raji cells.

The underlying mechanism of deguelin regulating the cell cycle in human Burkitt's lymphoma cell line Raji cells in vitro, and the cytotoxicity of deguelin to Raji cells and human peripheral blood monocular cells (PBMCs) were investigated. The effects of deguelin on the growth of Raji cells were studied by 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) assay. Apoptosis was detected through Hoechst 33258 staining. The effect of deguelin on the cell cycle of Raji cells was studied by a propidium iodide method. The expression levels of cyclin D1, P21 and pRb were examined by using Western blotting. The results showed that the proliferation of Raji cells was inhibited in the deguelin-treated group, with a 24-h IC(50) value of 21.61 nmol/L and a 36-h IC(50) value of 17.07 nmol/L. Proliferation in Raji cells was inhibited significantly by deguelin, while little change was observed in PBMCs. Deguelin induced G(2)/M arrest in Raji cells. The expression of cyclin D1, P21 and pRb was dramatically down-regulated by deguelin in a dose-dependent manner. It was concluded that deguelin could inhibit the proliferation of Raji cells by arresting the cells at G(2)/M phase and inducing the cell apoptosis. Moreover, deguelin selectively induced apoptosis of Raji cells with low toxicity to PBMCs. The antitumor effects of deguelin were related to the down-regulated expression of cyclin D1, P21 and pRb proteins.

[New concept and clinical application of colorectal intraepithelial neoplasia and carcinoma].

OBJECTIVE: To introduce the WHO 2000 diagnostic criteria of biopsy of colorectal intraepithelial neoplasia and carcinoma and to enhance diagnostic accuracy and avoid overdiagnosis and underdiagnosis. METHOD: The postoperative pathological examination and preoperative biopsy in 56 patients diagnosed as colorectal intraepithelial neoplasia and carcinoma before operation from January 2001 to October 2005 were compared retrospectively. RESULTS: Among the 56 cases, 16 patients were diagnosed by preoperative biopsy as carcinoma in situ, intramucosal carcinoma and adenocarcinoma, but according to the new standard, of them 14 cases should be revised to be higher grade colorectal intraepithelial neoplasia. CONCLUSIONS: Strictly adhere to the new WHO criteria, colorectal intraepithelial neoplasia and carcinoma can be diagnosed properly, but for the cases that submucosal muscular layer would not presented in biopsy, the diagnosis should be made by combining clinical findings and various examination results so as to avoid underdiagnosis and delay of treatment.