Biomedical subjects

Qiong Jiang

Publications and source records attributed to Qiong Jiang.

21 records · Page 2Linked to original sources

PubMed1998

Use of Carcinoembryonic Antigen Gene Promoter in Colorectal Carcinoma-specific Suicidal Gene Therapy.

The possibility of tumor-specific suicidal gene therapy of colorectalcarcinoma was investigated using carcinoembryonic antigen (CEA) -positive human colorectal carcinoma cell line LoVo and CEA-negative HeLa cell line as a model. After confirming cellular specificity of cea promoter by CAT assay, eukaryotic expression plasmid pCEACD was constructed in which the expresstion of E. coli cytosine deaminase (CD) gene was under the control of cea promoter. The expression of CD gene increased the sensitivity of LoVo cells to 5-fluorocytosine (5FC) by 750 fold, while the sensitivity of HeLa cells to 5FC was increased by only 7.5 fold. These results suggest that the expression of CD gene driven by cea promoter specifically killed CEA-positive colorectal carcinoma cells. Transmission electron microscopy and DNA fragmentation assay demonstrate that CD/5FC system induced apoptosis in LoVo cells.

Journal Article↗

PubMed1997

Expression of Cytosine Deaminase Gene in Human Colon Carcinoma Cells by Recombinant Retroviral Vector.

The recombinant retroviral vector pLCDSN containing E. coli cytosine deaminase gene was constructed. After packaging with PA317 cell line, the infectious particles were used to infect human colon carcinoma cell line LoVo. A single clone harbouring EC-CD gene was picked after G418 selection. There was no significant difference in cell growth curve or morphology between the LoVo/LCDSN and LoVo cells. Both of them were very sensitive to 5-FU in vitro (IC(50), approximately 0.5 &mgr;mol/L). However, the expression of the CD gene did increase the sensitivity of these cells to the nontoxic prodrug, 5-FC, decreasing the IC(50) for 5-FC from 22 000 &mgr;mol/L for parental LoVo cells to 13 &mgr;mol/L for LoVo/LCDSN cells. Obvious by side effect was also observed. When cells transduced with CD gene were mixed with wild type cells at a ratio of 30:70, above 80% of the cancer cells could be killed after treatment with a nontoxic concentration of 5-FC.

Journal Article↗

PubMedDate not supplied

Cell biology of IL-7, a key lymphotrophin.

IL-7 is essential for the development and survival of T lymphocytes. This review is primarily from the perspective of the cell biology of the responding T cell. Beginning with IL-7 receptor structure and regulation, the major signaling pathways appear to be via PI3K and Stat5, although the requirement for either has yet to be verified by published knockout experiments. The proliferation pathway induced by IL-7 differs from conventional growth factors and is primarily through posttranslational regulation of p27, a Cdk inhibitor, and Cdc25a, a Cdk-activating phosphatase. The survival function of IL-7 is largely through maintaining a favorable balance of bcl-2 family members including Bcl-2 itself and Mcl-1 on the positive side, and Bax, Bad and Bim on the negative side. There are also some remarkable metabolic effects of IL-7 withdrawal. Studies of IL-7 receptor signaling have yet to turn up unique pathways, despite the unique requirement for IL-7 in T cell biology. There remain significant questions regarding IL-7 production and the major producing cells have yet to be fully characterized.

Interleukin-7↗