new GM crop--plant made herceptin-- may provide herceptin at lower cost!

[Lani]

PLoS One. 2011 Mar 3;6(3):e17541.
Plant-Made Trastuzumab (Herceptin) Inhibits HER2/Neu+ Cell Proliferation and Retards Tumor Growth.
Komarova TV, Kosorukov VS, Frolova OY, Petrunia IV, Skrypnik KA, Gleba YY, Dorokhov YL.

A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.
Abstract
BACKGROUND: Plant biotechnology provides a valuable contribution to global health, in part because it can decrease the cost of pharmaceutical products. Breast cancer can now be successfully treated by a humanized monoclonal antibody (mAb), trastuzumab (Herceptin). A course of treatment, however, is expensive and requires repeated administrations of the mAb. Here we used an Agrobacterium-mediated transient expression system to produce trastuzumab in plant cells.

METHODOLOGY/PRINCIPAL FINDINGS: We describe the cloning and expression of gene constructs in Nicotiana benthamiana plants using intron-optimized Tobacco mosaic virus- and Potato virus X-based vectors encoding, respectively, the heavy and light chains of trastuzumab. Full-size antibodies extracted and purified from plant tissues were tested for functionality and specificity by (i) binding to HER2/neu on the surface of a human mammary gland adenocarcinoma cell line, SK-BR-3, in fluorescence-activated cell sorting assay and (ii) testing the in vitro and in vivo inhibition of HER-2-expressing cancer cell proliferation. We show that plant-made trastuzumab (PMT) bound to the Her2/neu oncoprotein of SK-BR-3 cells and efficiently inhibited SK-BR-3 cell proliferation. Furthermore, mouse intraperitoneal PMT administration retarded the growth of xenografted tumors derived from human ovarian cancer SKOV3 Her2+ cells.

CONCLUSIONS/SIGNIFICANCE: We conclude that PMT is active in suppression of cell proliferation and tumor growth.

PMID: 21390232 [PubMed - in process]