RT Journal Article
SR Electronic
T1 Lapatinib, a Dual EGFR and HER2 Kinase Inhibitor, Selectively Inhibits HER2-Amplified Human Gastric Cancer Cells and is Synergistic with Trastuzumab <em>In vitro</em> and <em>In vivo</em>
JF Clinical Cancer Research
JO Clin Cancer Res
FD American Association for Cancer Research
SP 1509
OP 1519
DO 10.1158/1078-0432.CCR-09-1112
VO 16
IS 5
A1 Wainberg, Zev A.
A1 Anghel, Adrian
A1 Desai, Amrita J.
A1 Ayala, Raul
A1 Luo, Tong
A1 Safran, Brent
A1 Fejzo, Marlena S.
A1 Hecht, J. Randolph
A1 Slamon, Dennis J.
A1 Finn, Richard S.
YR 2010
UL http://clincancerres.aacrjournals.org/content/16/5/1509.abstract
AB Purpose: HER2 amplification occurs in 18% to 27% of gastric and gastroesophageal junction cancers. Lapatinib, a potent ATP-competitive inhibitor simultaneously inhibits both EGFR and HER2. To explore the role of HER family biology in upper gastrointestinal cancers, we evaluated the effect of lapatinib, erlotinib, and trastuzumab in a panel of molecularly characterized human upper gastrointestinal cancer cell lines and xenografts.Experimental Design: EGFR and HER2 protein expression were determined in a panel of 14 human upper gastrointestinal cancer cell lines and HER2 status was assessed by fluorescent in situ hybridization. Dose-response curves were generated to determine sensitivity to lapatinib, erlotinib, and trastuzumab. In HER2-amplified cells, the combination of trastuzumab and lapatinib was evaluated using the median effects principal. The efficacy of lapatinib, trastuzumab, or the combination was examined in HER2-amplified xenograft models.Results: Lapatinib had concentration-dependent antiproliferative activity across the panel with the greatest effects in HER2-amplified cells. There was no association between EGFR protein expression and sensitivity to any of the HER-targeted agents. Cell cycle analysis revealed that lapatinib induced G1 arrest in sensitive lines and phosphorylated AKT and phosphorylated ERK were decreased in response to lapatinib as well. The combination of lapatinib and trastuzumab was highly synergistic in inhibiting cell growth with a combination index of &lt;1. The combination also induced greater decreases in AKT and ERK activation, G0-G1 cell cycle arrest, and increased rates of apoptosis. In vivo studies showed that the combination of lapatinib and trastuzumab had greater antitumor efficacy than either drug alone.Conclusion: Together, these data suggest that lapatinib has activity in HER2-amplified upper gastrointestinal cancer and supports the ongoing clinical investigation of lapatinib in patients with HER2-amplified disease. Clin Cancer Res; 16(5); 1509–19