Pertuzumab Increases 17-AAG-Induced Degradation of ErbB2, and This Effect Is Further Increased by Combining Pertuzumab with Trastuzumab
1
Institute of Pathology, Oslo University Hospital, Rikshospitalet University of Oslo, Oslo 0027, Norway
2
Roche Diagnostics GmbH, Pharma Research Penzberg, Nonnenwald 2, Penzberg 82377, Germany
3
Department of Pathology, Oslo University Hospital, Rikshospitalet, Post Box 4950 Nydalen, Oslo 0424, Norway
*
Author to whom correspondence should be addressed.
Pharmaceuticals 2012, 5(7), 674-689; https://doi.org/10.3390/ph5070674
Received: 20 April 2012 / Revised: 13 June 2012 / Accepted: 21 June 2012 / Published: 28 June 2012
(This article belongs to the Special Issue Hsp90 Inhibitors)
ErbB2 is an important oncogenic protein involved in carcinogenesis of, among others, breast, gastric, and ovarian carcinoma. Over-expression of ErbB2 is found in almost 20% of breast cancers, and this results in proliferative and anti-apoptotic signalling. ErbB2 is therefore an important treatment target. Antibodies recognizing full-length ErbB2 are clinically established, and drugs targeting the ErbB2 stabilizing heat shock protein 90 (Hsp90) are under clinical evaluation. We have investigated effects of the ErbB2-binding antibodies trastuzumab and pertuzumab alone and in combination, as well as the effect of the antibodies in combination with the Hsp90 inhibitor 17-AAG. Our results confirm the notion that combination of different ErbB2-binding antibodies more efficiently down-regulates ErbB2 than does one antibody in isolation. Additionally, our data demonstrate that ErbB2 is most efficiently down-regulated upon incubation with anti-ErbB2 antibodies in combination with Hsp90 inhibitors. The combination of anti-ErbB2 antibodies, and especially the combination of antibodies with 17-AAG, did also increase the inhibition of Akt activation of either agent, which could suggest an anti-proliferative effect. In such case, combining these agents could be beneficial in treatment of tumors not responding to trastuzumab only.
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Keywords:
17-AAG; pertuzumab; trastuzumab; Hsp90; ErbB2
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MDPI and ACS Style
Hughes, J.B.; Rødland, M.S.; Hasmann, M.; Madshus, I.H.; Stang, E. Pertuzumab Increases 17-AAG-Induced Degradation of ErbB2, and This Effect Is Further Increased by Combining Pertuzumab with Trastuzumab. Pharmaceuticals 2012, 5, 674-689.
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