The carcinogenesis and development is a progress of multi-gene alterations in the human gastric cancer (HGC)．In order to determine the relation between the aberration of these genes and gastric cancer，we chose c-met (7q31)、hMLH1 (3p21)、E-cadherin (16q22.1) and HLA loci DQA1、DR2、DR3、DR4、DR7、DR9 and detected their changes in 32 tumor specimens of intestinal type HGC and 4 cell lines of gastric cancer by performing analysis of SSP/PCR、PCR/SSCP and MSI technigues．Our data show that none point mutation was detected in c-met gene．We examined two microsatellites loci D3S1298 and D3S1561 in hMLH1 gene and detected that 6 cases retain MSI (Microsatellite Instability) and 2 cases of LOH (Loss of Heterozygosity) at D3S1298 and 2 cases of MSI at D3S1561．We also examined E-cadherin gene at two microsatellites loci D16S3083 and D16S3095 close to the gene and detected that 5 cases retain MSI and 1 case of LOH at D16S3083 and no change at D16S3095．The point mutation incidence of HLA-DR4 loci is 9/20 (45%)，higher than the other loci in HLA-Ⅱ．High frequent deletion，expression deregulation and methylation of mts1/p16 gene were detected in cell lines and solid tumors from human gastric cancer patients． 　　Our data showed that the point mutation of c-met gene is not the main pattern of alteration in intestinal type HGC that is consistent with the previous results．E-cadherin and hMLH1 are related to intestinal type HGC but whether they are susceptibility gene still need further study．The point mutation of the HLA-Ⅱ loci DR4 is closely related to intestinal type HGC．Methylation of mts1/p16 gene 5 CpG island might be plays an important role in the carcinogenesis in HGC．

The p53 gene is one of the most common targets for genetic abnormalities in human tumors. Restoring wild - type p53 gene (wt-p53) into cancer cells which have p53 deletion is a strategy in cancer gene therapy. In order to explore the feasibility of this hypothesis, we selected a gastric cancer cell line BGC823 which was confirmed having deletion of chromosome 17pl3 and decreased expression level of p53 mRNA . We transfected construct pC53SN3 containing wt - p53 into BGC823 cell line with lipofectin mediated gene transferration, and G418 resistant colonies were characterized by using analysis of PCR, Southern blot hybridization, Northern blot hybridization and Western blot hybridization. These data showed that exogenous wt-p53 had successfully transferred into BGC823 cells and obtained high expression. The cell growth rates in regular medium and soft agar were inhibited from 30 to 40 percent in the BGC823 cells transfected with wt - p53. The tumorigenicity in nude mice showed that one of four mice failed to form tumor and three of them delayed to form tumor from 7 to 14 days comparing with monk and parent BGC823 cells. These results suggested that exogenous wt -p53 could suppress the growth ability and tumorigenicity of human gastric cancer cells. The method of using lipofectin mediated wt-p53 gene transfection may have a potentially therapeutic effect on human gastric cancer.

Our previous investigation have demonstrated that multiple genes alterations, such as deletion of Rb, p53 and p16 gene, point mutation of H-ras gene were detected in cell line and solid tumor of human gastric cancer. We have transfect-ed the independent construct containing Rb, p53, p16 and expression of H-ras antisense RNA respectively into human gastric cancer cell line, and we have analyzed the biological properties of several independent transfectant cell lines, which express exogenous Rb, p53, p16 and H-ras antisense RNA respectively. The cell growth ability was inhibited by introduction of p53 and H-ras antisense RNA, and tumorigenicity also suppressed significantly by p53, p16 and H-ras antisense RNA. These results indicated that alterations of p53, p16 and H-ras gene were involved in human gastric car-cinogenesis.

The amplification,rearrangement and deletion of c-Ha-ras,K-ras and N-ras were studied in 33 cases of gastric cancerous and juxtacancerous tissues.It was found that the amplification rearangement,and deletion of c-Ha-ras were shown in 25.8% (8/33) of cases and the ampli-cation of K-ras in 3.8% (1/26).No such changes was found for N-ras.

The changes of several oncogenes and suppressor genes in the specimens of cancerous and juxtacancerous tissues of 42 cases of gastric cancer were studied with Southern blot hybridization and PCR-RELP method.The probes used were c-Ha-ras,K-ras,N-ras,N-myc,c-myc,hst,EGFR,c-erbB-2,p53 and Rb.Amplification,rearrangement,and deletion of c-Ha-ras were detected in 8/33 (25.8%) cases of gastric cancer (amplification or rearrangement of hst and c-erbB-2 in 11/42 (26.6%) and 12/42 (29.2%) cases respectively (amplification of EGFR in 21.4% of cas-esideletion or rearrangement of p53 and Rb in S/30 (30%) and 2/15 (13%) cases respectively) and amplification or rearrangement of N-ras (0/33),K-ras (1/26),N-myc (1/26),and c-myc (1/ 35) was only rarely encounted.The point mutation in codon 248 and 249 of p53 in gastric cancer was analyzed.2 cases of the 42 harbored point mutation in codon 248 of p53.These findings suggest that e-Ha-ras,hst,c-erbB-2,EGFR and p53 may be the hot point genes in the occurrence and development of gastric cancer.

Ubiquitin-proteasome pathway is an important mechanism regulating many processes of cellular biology,and also a potential target for abnormal regulation associated with malignancy. This pathway may up-regulate or down-regulate the expression of some tumor-inhibitory genes, transcriptional factors and cyclins,and alter the generation of MHC-I-restricting antigen peptides through the activity of specific proteasome, and consequently,participates in the genesis and progression of malignancy.

OBJECTIVETo identify genes associated with the chronic progression of renal disease and a stragalus and angelica (A&A)'s renal protective effects.

METHODSThe technique of silver staining mRNA differential display (DD) was used to investigate changes of gene expression in normal, sclerotic and A&A treated sclerotic kidneys. We isolated genes differentially expressed during the progression of renal disease which could be normalized by A&A.

RESULTSSeveral genes related to A&A's protective effects were isolated and one of them was confirmed by Northern blot.

CONCLUSIONSilver staining mRNA differential display is a simple and effective technique for isolating differentially expressed genes. The isolated new gene may be related to the progression of chronic renal disease and contribute to A&A's protective effects.

Angelica sinensis ; Animals ; Astragalus Plant ; Drugs, Chinese Herbal ; pharmacology ; Kidney ; drug effects ; metabolism ; Kidney Diseases ; drug therapy ; metabolism ; Male ; Phytotherapy ; Polymerase Chain Reaction ; Protective Agents ; pharmacology ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Staining and Labeling