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A new human antitumor immunoreagent specific for ErbB2
Claudia De Lorenzo1, Donald B Palmer, Renata Piccoli
1Department of Biological Chemistry, University of Naples Federico II, via Mezzocannone 16, 80134 Naples, Italy.
Purpose:
Our aim was to isolate a novel human mini-antibody(scFv) that specifically targets ErbB2-positive cancer cells. ErbB2, a tyrosinekinase receptor, is overexpressed in clinically significant tumors, such as breast, ovary, and lung carcinomas. In normal tissues, it is expressed only in certain epithelial cell types.
Experimental Design:
A large phagemid library (Griffin.1 library) of human scFv was used for the isolation of the ErbB2-specific scFv. A very effective strategy was developed for the isolation, consisting in a double subtractive selection, the use of two different combinations of "positive," i.e., ErbB2-bearing, and "negative" cell lines.
Results:
Here we report the isolation of the first human anti-ErbB2 mini-antibody endowed with antitumor action. Both in its soluble and phage format, it binds specifically to ErbB2, inhibits its autophosphorylation, is internalized by target cells, and exerts a strong and specific antiproliferative action on ErbB2-positive target cells. A correlation was found between the extent of this antiproliferative effect and the expression levels of ErbB2 on target cells, with a strong cytotoxicity for hyper-expressing cells, such as SKBR3, in which apoptosis was evidenced.
Conclusions:
This scFv is a potentially effective immunoreagent for diagnostics and therapeutics of certain cancers, both as a readily diffused molecule in solid tumors and as an essential asset for the construction of fully human anticancer drugs.
Insights
Researchers isolated a novel human mini-antibody (scFv) targeting ErbB2-positive cancers. This antibody inhibits ErbB2, internalizes into cancer cells, and shows potent antitumor effects, especially in high-ErbB2 expressing tumors.
Area of Science:
- Oncology
- Immunology
- Biotechnology
Background:
- ErbB2 (Human Epidermal growth factor Receptor 2) is a tyrosine kinase receptor.
- ErbB2 is overexpressed in various significant carcinomas, including breast, ovary, and lung cancers.
- ErbB2 expression is limited in normal tissues, making it a specific cancer target.
Purpose of the Study:
- To isolate a novel human single-chain variable fragment (scFv) mini-antibody.
- To develop an scFv that specifically targets ErbB2-positive cancer cells.
Main Methods:
- Utilized a large phagemid library (Griffin.1) for scFv isolation.
- Employed a double subtractive selection strategy with ErbB2-positive and negative cell lines.
Main Results:
- Isolated the first human anti-ErbB2 mini-antibody with antitumor activity.
- The scFv specifically binds ErbB2, inhibits its autophosphorylation, and is internalized by target cells.
- Demonstrated potent antiproliferative action on ErbB2-positive cells, with increased cytotoxicity and apoptosis in hyper-expressing cells like SKBR3.
Conclusions:
- The isolated scFv is a promising immunoreagent for cancer diagnostics and therapeutics.
- It can be utilized as a diffused molecule in solid tumors.
- This scFv is valuable for developing fully human anticancer drugs.