Cancer Research and Treatment

Effects of Wild - type p53 Gene Transfection into Human Colon Cancer Cell Line: Hyun Ok Kim, Woo Ho Kim, Soo In Bae, He Won Lee, Chong Jai Kim, Sung Youl Hong, Yong Il Kim; J Korean Cancer Assoc. 1999;31(2):367-376.

Abstract PDF: PURPOSE
In colon cancer, the most frequent genetic alteration is found in p53 tumor suppressor gene residing on the short arm of chromosome 17. In order to investigate the significance of wild-type p53, we transfected wild type p53 into human colon cancer cell lines and analysed tbeir biologic effects.
MATERIALS AND METHODS
For analysis of p53 status in cell lines, polymerase chain reaction-single stranded confonnation polymorphism (PCR-SSCP), PCR-direct sequencing and Western blot analysis were employed. Transient transfection with liposome-p53 complex was followed by cell biologic assay.
RESULTS
We found that twelve of fifteen human colon cancer cell lines showed mutation of p53 by PCR-SSCP method. These results almost corresponded to p53 protein accumulations assessed by Westem blot using PAbl801. After transfection with lipafect- AMINE and wild type p53 complex on p53 mutant type cell line (LS1034), viability was reduced to 17.9%, and invasiveness was reduced to 37.3%. Morphologically, wild type p53 transfected cells showed lumen formation and apoptosis after induction of differentiation by Matrigel.
CONCLUSION
Wild type p53 transfection into p53 mutated colon cancer ceil line resulted in restoration of tumor suppressor effect of p53, and this model would be one of the experimental systems for p53-based gene therapy.

3,216 View
40 Download

Liposomes as Acitivators of Lipophilic Platinum (2 ) Complexes: In Sook Han, Young Jae Lee; J Korean Cancer Assoc. 1999;31(1):180-187.

Abstract PDF: PURPOSE
The goal of this study is to understand the activation processes that take place within the liposomal formulation of lipophilic diaminocyclohexane platinum (DACH-Pt) complexes, to identify the activated species of this class of compounds, and to use that information to develop a reproducible liposomal formulation of DACH-Pt complexes.
MATERIALS AND METHODS
Liposomal DACH-Pt complexes were prepared by lyophilization-rehydration method using PC, PG and PA. Their intraliposomal stability and biological activity were determined by HPLC and in vitro/in vivo experiments.
RESULTS
DACH-Pt complexes in a liposomal formulation have shown significant promise in preclinical studies and clinical phase I, II trials. Interestingly, they are prodrugs which converts into one or more undetennined activated platinum species within the liposomes ex vivo. Our studies have shown that the stability of liposomal DACH-Pt complexes is inversely related with the antitumor activity of those complexes. The configuratian of leaving group in the complexes and pH of the liposome suspension affect significantly the degradation/activation process that takes place within the liposomes. DACH-Pt complexes with linear (L10) leaving groups are more stable than complexes with branched ones (B10 and NDDP), but also significantly less potent. The presence of PG and PA in the liposome is a prerequisite for the degradation/activation process of DACH-Pt complexes. As PG and PA formulation gave more dramatic changes of the original complexes than PC alone due to lower pH, the cytotoxicity and antitumor activity at those fonnulations increased against PC alone. DACH-Pt complexes are very stable in liposomes containing PC alone but inactive in vitro/in vivo experiments.
CONCLUSION
These results also support that the active species produced within the liposomal DACH-Pt complexes is DACH-Pt-Cl2.

2,400 View
17 Download

An Antibody Against E2 / MIC2 Antigen ( CD99 ) : Indentification and Characterization: Kyeong Cheon Jung, Tae Jin Kim, Doo Hyun Chung, Kuhn Kuk Lee, Jang Hee Hahm, Seong Hoe Park; J Korean Cancer Assoc. 1996;28(2):350-358.

Abstract PDF: Liposome-mediated gene transfer offers the potential to introduce DNA encoding therapeutic DNA to treat human disease. Several genes have been used in gene therapy to stimulate immune response in malignancy, and allogeneic major histocompatibility complex (MHC) proteins also serve as a potent stimulus to the immune system. This study was performed to determine the transfection efficiency and safety of liposome- mediated gene delivery into human cancer cell lines and animals. Placental alkaline phosphatase gene as a reporter was transfected into PCI-13 and NCI-H522 cell lines, and the expression was determined in individual transfected cells by histochemical staining. The transfectian efficiency was the highest at 24 ￥ig of DNA mixed with 10￥il of lipofectamine in vitro, HLA-B7 DNA as a therapeutic gene was transfected into cell lines and injected subcutaneously into the rabbits. The HLA-B7 gene expression was successfully identified by RT-PCR in vivo and in vitro. Twenty percents of the cells expressed HLA-B7 proteins which were analyzed by flow cytometry. In rabbit model, no pyrogenic response was ob- served after subcutaneous injection of HLA-B7/liposome complexes. The expression of injected HLA-B7 gene was restricted within the injected skin. These data showed the feasibility and safety of liposome-mediated gene transfer. These findings will provide a basis to develop strategies for the gene therapy of human cancer.

2,547 View
16 Download

Preclinical Study of HLA-B7 DNA / Liposome Complex for Gene Therapy: Seong Jun Yoon, Won Seok Kim, Jae Go Seol, Sagn Goo Lee, Kee Hyung Lee, Dae Seog Heo, Noe Kyeong Kim; J Korean Cancer Assoc. 1996;28(2):358-368.

PDF

2,402 View
14 Download

Search