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Intracellular expression of an antibody fragment-neutralizing p21 ras promotes tumor regression
O Cochet1, M Kenigsberg, I Delumeau
1Laboratoire de Biotechnologie des Anticorps, Institut Curie, Paris, France.
Abstract:
Mutated ras genes are found in a large number of human tumors and, therefore, constitute one of the primary targets for cancer treatment. Microinjection of the neutralizing anti-Ras monoclonal antibody Y13-259 was previously reported to induce transient phenotypic reversion of ras-transformed rodent fibroblasts in vitro. We have prepared a single-chain Fv fragment (scFv) derived from Y13-259, and here, we show that intracellular expression of the scFv led to the specific inhibition of the Ras signaling pathway in Xenopus laevis oocytes and NIH3T3 fibroblasts. Moreover, neutralizing Ras with the scFv specifically promoted apoptosis in vitro in human cancer cells but not in untransformed cells. As a step toward cancer gene therapy, we finally demonstrated that intratumor transduction of HCT116 colon carcinoma cells with the anti-Ras scFv using an adenoviral vector elicited sustained tumor regression in nude mice.
Insights
This study developed an anti-Ras single-chain variable fragment (scFv) that inhibits Ras signaling, promotes cancer cell apoptosis, and causes tumor regression in mice, offering a potential cancer gene therapy.
Area of Science:
- Oncology
- Molecular Biology
- Gene Therapy
Background:
- Mutated ras genes are key targets in human cancers.
- Previous studies showed anti-Ras antibodies induce transient reversion in ras-transformed cells.
Purpose of the Study:
- To develop and evaluate a single-chain variable fragment (scFv) derived from the anti-Ras antibody Y13-259 for cancer therapy.
- To assess the efficacy of intracellular anti-Ras scFv in inhibiting Ras signaling, inducing apoptosis, and causing tumor regression.
Main Methods:
- Prepared a single-chain variable fragment (scFv) from the Y13-259 antibody.
- Expressed scFv intracellularly in Xenopus laevis oocytes and NIH3T3 fibroblasts to inhibit Ras signaling.
- Treated human cancer cells and untransformed cells with scFv in vitro.
- Administered anti-Ras scFv via adenoviral vector intratumorally in a mouse model.
Main Results:
- Intracellular scFv expression specifically inhibited the Ras signaling pathway.
- Neutralizing Ras with scFv promoted apoptosis in human cancer cells but not normal cells.
- Intratumor delivery of anti-Ras scFv using an adenoviral vector led to sustained tumor regression in mice.
Conclusions:
- The anti-Ras scFv is a potent inhibitor of Ras signaling and a promising candidate for cancer gene therapy.
- Intracellular expression of anti-Ras scFv can specifically target cancer cells, induce apoptosis, and mediate tumor regression.