erbB-2 is a potent oncogene when overexpressed in NIH/3T3 cells.

Area of Science:

• Molecular Biology
• Oncology
• Cancer Genetics

Background:

• The erbB-2 gene is frequently amplified or overexpressed in various human tumors.
• erbB-2 encodes a protein similar to growth factor receptors.

Purpose of the Study:

• To investigate the oncogenic potential of the erbB-2 gene.
• To understand the role of erbB-2 overexpression in malignant transformation.

Main Methods:

• Expressing erbB-2 complementary DNA in NIH/3T3 cells using different promoters (SV40 and Moloney murine leukemia virus LTR).
• Assessing the transforming activity and protein expression levels of erbB-2.
• Comparing NIH/3T3 cell findings with human mammary tumor cells overexpressing erbB-2.

Main Results:

• erbB-2 lacked transforming activity in NIH/3T3 cells at detectable expression levels.
• A significant increase in erbB-2 expression activated it as a potent oncogene.
• High erbB-2 product levels in NIH/3T3 cells mirrored those in human mammary tumors, correlating with malignant transformation.

Conclusions:

• Gene overexpression can confer oncogenic properties to growth factor receptor-like genes.
• Overexpression of erbB-2 plays a functional role in the development of human malignancies.
• This study identifies a novel mechanism for oncogene activation.