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[DNA transformation activity of a human gastrocarcinoma cell line]
Abstract:
DNAs of three cell lines of human gastrocarcinoma (MGC-803, BGC-823 and PACM-82) and two fresh solid tumors of human stomach cancer were used to transfect NIH3T3 and Rat-1 cells. The transformed cells were selected with high concentration of glucose and low concentration of serum, or with medium containing Geneticin (G418) after co-transfection of pSVneo and DNAs of stomach cancer cell line or primary transformants. From the second round transfection, we had obtained transformants which could grow with high colony forming efficiency in soft agarose and were tumorigenic in nude mice. The southern blot analysis showed that the cellular DNA of the transformants contained human Alu repeat sequence and the transformed gene from stomach cancer cell line (BGC-823) and was homologous to proto-oncogene c-Ha-ras. The transforming gene is able to induce neoplastic transformation of NIH3T3 and Rat-1 cells.
Insights
Researchers identified a human stomach cancer gene that transforms normal cells into cancerous ones. This proto-oncogene, homologous to c-Ha-ras, was isolated from gastrocarcinoma cell lines and primary tumors.
Area of Science:
- Molecular Biology
- Oncology
- Genetics
Background:
- Human gastrocarcinoma cell lines and primary stomach tumors harbor transforming genes.
- Identifying these genes is crucial for understanding cancer development.
Purpose of the Study:
- To isolate and characterize transforming genes from human stomach cancer.
- To investigate the oncogenic potential of these genes in vitro and in vivo.
Main Methods:
- DNA transfection of NIH3T3 and Rat-1 cells with human stomach cancer DNA.
- Selection of transformed cells using Geneticin (G418) or specific media conditions.
- Analysis of transformants for anchorage-independent growth (soft agarose) and tumorigenicity in nude mice.
- Southern blot analysis to identify human DNA sequences and homology to known oncogenes.
Main Results:
- Transformed cell lines exhibited high colony-forming efficiency in soft agarose and formed tumors in nude mice.
- Southern blot confirmed the presence of human Alu sequences and a transforming gene from BGC-823 cells.
- The identified transforming gene is homologous to the proto-oncogene c-Ha-ras.
- This gene induced neoplastic transformation in NIH3T3 and Rat-1 cells.
Conclusions:
- A transforming gene from human stomach cancer, homologous to c-Ha-ras, was identified.
- This gene possesses oncogenic potential, capable of inducing cellular transformation and tumorigenesis.
- The findings contribute to understanding the molecular basis of human stomach cancer.