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cMET Activation and EGFR-Directed Therapy Resistance in Triple-Negative Breast Cancer.

Sohn J, Liu S, Parinyanitikul N, Lee J, Hortobagyi GN, Mills GB, Ueno NT, Gonzalez-Angulo AM - J Cancer (2014)

Bottom Line: However, anti-EGFR therapies have not been effective in these patients.In western blotting, combination therapy resulted in abrogation of pAKT and pMAPK while monotherapy did not.Targeting both EGFR and MET receptors may provide an effective therapeutic strategy in TNBC.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA ; 2. Division of Medical Oncology, Department of Internal Medicine, Breast Cancer Clinic, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.

ABSTRACT

Background: EGFR expression and pathway activation are common in triple-negative breast cancer (TNBC). However, anti-EGFR therapies have not been effective in these patients. We aimed to study the efficacy of targeting MET in overcoming resistance to EGFR therapy in TNBC cell lines.

Methods: TNBC lines (MDA-MB-468, HCC-1395, and MDA-MB-231), and a hormone receptor-positive breast cancer line (T47D) were stimulated with epidermal growth factor (EGF) and hepatocyte growth factor (HGF). Lines were then treated with different concentrations of EGFR inhibitors (gefitinib or cetuximab), with or without a MET tyrosine kinase inhibitor (EMD 1214063). Proliferation was measured by MTS assay, in soft agar and with a matrigel assay. Synergy was measured with Calcusyn. Protein expression and signaling were examined with immunoblotting.

Results: There was activation of ligand-receptor-downstream signaling pathways in MDA-MB-468 and HCC-1395 upon stimulation with EGF and HGF. In these cell lines, we observed synergism when combining EGFR and MET inhibitors. These results were observed across assays. In western blotting, combination therapy resulted in abrogation of pAKT and pMAPK while monotherapy did not.

Conclusion: Our data demonstrate that dual EGFR/MET inhibition is synergistic in TNBC. Targeting both EGFR and MET receptors may provide an effective therapeutic strategy in TNBC.

No MeSH data available.


Related in: MedlinePlus

Phospho-receptor tyrosine kinase array results in MDA-MB-468. After stimulation of EGF and HGF and after treatment of gefitinib and gefitinib plus EMD 121463: MDA-MB-468 in 100mm dish was harvested as described in western blotting and Phospho-Receptor Tyrosine Kinase (RTK) antibody arrays (R&D System, #ARY-001, Minneapolis, MN) were performed as recommended but with 450ug protein lysate per array.
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Figure 7: Phospho-receptor tyrosine kinase array results in MDA-MB-468. After stimulation of EGF and HGF and after treatment of gefitinib and gefitinib plus EMD 121463: MDA-MB-468 in 100mm dish was harvested as described in western blotting and Phospho-Receptor Tyrosine Kinase (RTK) antibody arrays (R&D System, #ARY-001, Minneapolis, MN) were performed as recommended but with 450ug protein lysate per array.

Mentions: Using phospho-receptor tyrosine kinase array, we investigated whether alternative growth factor receptors responded to EGF or HGF and whether gefitinib or the combination of gefitinib and EMD 121463 would alter the activity. In MDA MB-468 cells, EGF increased levels of pEGFR and pErbB3 whereas EGF and HGF together increased phosphorylated MET, EGFR and ErbB3. ErbB3 plays a critical role in escaping from EGFR TKI inhibition via Akt negative feedback 15. Geifitinb and EMD 121463 abrogated pMET as well as pErbb3 (Fig. 7). The effects of the combination of gefitinib and EMD 121463 do not seem to be compensated by activation of other RTKs in MDA MB-468 cells (Fig.7). Similar findings were obtained with HCC-1395 (data not shown).


cMET Activation and EGFR-Directed Therapy Resistance in Triple-Negative Breast Cancer.

Sohn J, Liu S, Parinyanitikul N, Lee J, Hortobagyi GN, Mills GB, Ueno NT, Gonzalez-Angulo AM - J Cancer (2014)

Phospho-receptor tyrosine kinase array results in MDA-MB-468. After stimulation of EGF and HGF and after treatment of gefitinib and gefitinib plus EMD 121463: MDA-MB-468 in 100mm dish was harvested as described in western blotting and Phospho-Receptor Tyrosine Kinase (RTK) antibody arrays (R&D System, #ARY-001, Minneapolis, MN) were performed as recommended but with 450ug protein lysate per array.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4216798&req=5

Figure 7: Phospho-receptor tyrosine kinase array results in MDA-MB-468. After stimulation of EGF and HGF and after treatment of gefitinib and gefitinib plus EMD 121463: MDA-MB-468 in 100mm dish was harvested as described in western blotting and Phospho-Receptor Tyrosine Kinase (RTK) antibody arrays (R&D System, #ARY-001, Minneapolis, MN) were performed as recommended but with 450ug protein lysate per array.
Mentions: Using phospho-receptor tyrosine kinase array, we investigated whether alternative growth factor receptors responded to EGF or HGF and whether gefitinib or the combination of gefitinib and EMD 121463 would alter the activity. In MDA MB-468 cells, EGF increased levels of pEGFR and pErbB3 whereas EGF and HGF together increased phosphorylated MET, EGFR and ErbB3. ErbB3 plays a critical role in escaping from EGFR TKI inhibition via Akt negative feedback 15. Geifitinb and EMD 121463 abrogated pMET as well as pErbb3 (Fig. 7). The effects of the combination of gefitinib and EMD 121463 do not seem to be compensated by activation of other RTKs in MDA MB-468 cells (Fig.7). Similar findings were obtained with HCC-1395 (data not shown).

Bottom Line: However, anti-EGFR therapies have not been effective in these patients.In western blotting, combination therapy resulted in abrogation of pAKT and pMAPK while monotherapy did not.Targeting both EGFR and MET receptors may provide an effective therapeutic strategy in TNBC.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA ; 2. Division of Medical Oncology, Department of Internal Medicine, Breast Cancer Clinic, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.

ABSTRACT

Background: EGFR expression and pathway activation are common in triple-negative breast cancer (TNBC). However, anti-EGFR therapies have not been effective in these patients. We aimed to study the efficacy of targeting MET in overcoming resistance to EGFR therapy in TNBC cell lines.

Methods: TNBC lines (MDA-MB-468, HCC-1395, and MDA-MB-231), and a hormone receptor-positive breast cancer line (T47D) were stimulated with epidermal growth factor (EGF) and hepatocyte growth factor (HGF). Lines were then treated with different concentrations of EGFR inhibitors (gefitinib or cetuximab), with or without a MET tyrosine kinase inhibitor (EMD 1214063). Proliferation was measured by MTS assay, in soft agar and with a matrigel assay. Synergy was measured with Calcusyn. Protein expression and signaling were examined with immunoblotting.

Results: There was activation of ligand-receptor-downstream signaling pathways in MDA-MB-468 and HCC-1395 upon stimulation with EGF and HGF. In these cell lines, we observed synergism when combining EGFR and MET inhibitors. These results were observed across assays. In western blotting, combination therapy resulted in abrogation of pAKT and pMAPK while monotherapy did not.

Conclusion: Our data demonstrate that dual EGFR/MET inhibition is synergistic in TNBC. Targeting both EGFR and MET receptors may provide an effective therapeutic strategy in TNBC.

No MeSH data available.


Related in: MedlinePlus