Breast tumor cells isolated from in vitro resistance to trastuzumab remain sensitive to trastuzumab anti-tumor effects in vivo and to ADCC killing
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An understanding of model systems of trastuzumab (Herceptin) resistance is of great importance since the humanized monoclonal antibody is now used as first line therapy with paclitaxel in patients with metastatic Her2 overexpressing breast cancer, and the majority of their tumors has innate resistance or develops acquired resistance to the treatment. Previously, we selected trastuzumab-resistant clonal cell lines in vitro from trastuzumab-sensitive parental BT-474 cells and showed that cloned trastuzumab-resistant cell lines maintain similar levels of the extracellular Her2 receptor, bind trastuzumab as efficiently as the parental cells, but continue to grow in the presence of trastuzumab and display cell cycle profiles and growth rates comparable to parental cells grown in the absence of trastuzumab (Kute et al. in Cytometry A 57:86–93, 2004). We now show that trastuzumab-resistant and trastuzumab-sensitive cells both surprisingly display trastuzumab-mediated growth inhibition in athymic nude mice. This demonstrates that resistance developed in vitro is not predictive of resistance in vivo. The observation that in vitro resistant cells are sensitive to trastuzumab in vivo could be explained by antibody dependant cellular cytotoxicity (ADCC). Therefore, both parental and trastuzumab-resistant cells were assayed for ADCC in real time on electroplates with and without trastuzumab in the presence of a natural killer cell line (NK-92), and granulocyte or mononuclear cellular fractions isolated from human peripheral blood. Mononuclear cells and NK-92 cells were more effective in killing both parental and trastuzumab-resistant cells in the presence of trastuzumab. Both trastuzumab-resistant cells and trastuzumab-sensitive cells showed similar susceptibility to ADCC despite displaying divergent growth responses to trastuzumab. The granulocyte fraction was able to kill these cells with equal efficacy in the presence or absence of trastuzumab. These results support a model of trastuzumab tumor cell killing in vivo mediated primarily by ADCC from the mononuclear fraction of innate immune cells and suggest that in the clinical setting not only should changes in signaling transduction pathways be studied in acquired tumor resistance to trastuzumab, but also mechanisms by which tumors impede immune function should be evaluated.
KeywordsADCC Trastuzumab Herceptin Breast cancer Resistance BT-474
This work was performed from a grant from the Vaughn Jordon Foundation and from support of the pathology department and Wake Forest University Cancer Center. We would also like to thank Ms Debra Holder who help with the editing of the manuscript and Dr. Mark Willingham and Dr. Zheng Cui who provided comments and suggestions. Finally, I would like to thank Dr. Greg Russell for his help with the statistics.
- 1.Barok M, Isola J, Palyi-Krekk Z, Nagy P, Juhasz I, Vereb G, Kauraniemi P, Kapanen A, Tanner M, Vereb G, Szollosi J (2007) Trastuzumab causes antibody-dependent cellular cytotoxicity-mediated growth inhibition of submacroscopic JIMT-1 breast cancer xenografts despite intrinsic drug resistance. Mol Cancer Ther 6:2065–2072PubMedCrossRefGoogle Scholar
- 3.Burstein HJ, Harris LN, Gelman R, Lester SC, Nunes RA, Kaelin CM, Parker LM, Ellisen LW, Kuter I, Gadd MA, Christian RL, Kennedy PR, Borges VF, Bunnell CA, Younger J, Smith BL, Winer EP (2003) Preoperative therapy with trastuzumab and paclitaxel followed by sequential adjuvant doxorubicin/cyclophosphamide for HER2 overexpressing stage II or III breast cancer: a pilot study. J Clin Oncol 21:46–53PubMedCrossRefGoogle Scholar
- 8.Drugger DL, Hollingshead PG, Wong D, Romero M, Erickson SL, RH S (2002) Acquistion of Herceptin resistance by HER2 mutation in the HER2 transgenic mouse breast cancer model. Proceedings of the 93rd Annual Meeting of the American Association Cancer Research, San FranciscoGoogle Scholar
- 9.Gennari R, Menard S, Fagnoni F, Ponchio L, Scelsi M, Tagliabue E, Castiglioni F, Villani L, Magalotti C, Gibelli N, Oliviero B, Ballardini B, Da Prada G, Zambelli A, Costa A (2004) Pilot study of the mechanism of action of preoperative trastuzumab in patients with primary operable breast tumors overexpressing HER2. Clin Cancer Res 10:5650–5655PubMedCrossRefGoogle Scholar
- 13.Kostler WJ, Schwab B, Singer CF, Neumann R, Rucklinger E, Brodowicz T, Tomek S, Niedermayr M, Hejna M, Steger GG, Krainer M, Wiltschke C, Zielinski CC (2004) Monitoring of serum Her-2/neu predicts response and progression-free survival to trastuzumab-based treatment in patients with metastatic breast cancer. Clin Cancer Res 10:1618–1624PubMedCrossRefGoogle Scholar
- 16.Nagata Y, Lan KH, Zhou X, Tan M, Esteva FJ, Sahin AA, Klos KS, Li P, Monia BP, Nguyen NT, Hortobagyi GN, Hung MC, Yu D (2004) PTEN activation contributes to tumor inhibition by trastuzumab, and loss of PTEN predicts trastuzumab resistance in patients. Cancer Cell 6:117–127PubMedCrossRefGoogle Scholar
- 20.Piccart-Gebhart MJ, Procter M, Leyland-Jones B, Goldhirsch A, Untch M, Smith I, Gianni L, Baselga J, Bell R, Jackisch C, Cameron D, Dowsett M, Barrios CH, Steger G, Huang CS, Andersson M, Inbar M, Lichinitser M, Lang I, Nitz U, Iwata H, Thomssen C, Lohrisch C, Suter TM, Ruschoff J, Suto T, Greatorex V, Ward C, Straehle C, McFadden E, Dolci MS, Gelber RD (2005) Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer. N Engl J Med 353:1659–1672PubMedCrossRefGoogle Scholar
- 23.Slamon DJ, Leyland-Jones B, Shak S, Fuchs H, Paton V, Bajamonde A, Fleming T, Eiermann W, Wolter J, Pegram M, Baselga J, Norton L (2001) Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2. N Engl J Med 344:783–792PubMedCrossRefGoogle Scholar
- 28.Varchetta S, Gibelli N, Oliviero B, Nardini E, Gennari R, Gatti G, Silva LS, Villani L, Tagliabue E, Menard S, Costa A, Fagnoni FF (2007) Elements related to heterogeneity of antibody-dependent cell cytotoxicity in patients under trastuzumab therapy for primary operable breast cancer overexpressing Her2. Cancer Res 67:11991–11999PubMedCrossRefGoogle Scholar
- 29.Vogel CL, Cobleigh MA, Tripathy D, Gutheil JC, Harris LN, Fehrenbacher L, Slamon DJ, Murphy M, Novotny WF, Burchmore M, Shak S, Stewart SJ, Press M (2002) Efficacy and safety of trastuzumab as a single agent in first-line treatment of HER2-overexpressing metastatic breast cancer. J Clin Oncol 20:719–726PubMedCrossRefGoogle Scholar