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Y.W. Moon
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MINI 09 - Drug Resistance (ID 107)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:L. Villaruz, J. Minna
- Coordinates: 9/07/2015, 16:45 - 18:15, 205+207
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MINI09.07 - Activation of the MET Kinase Confers Acquired Resistance to FGFR-Targeted Therapy in FGFR-Dependent Squamous Cell Carcinoma of the Lung (ID 1212)
17:20 - 17:25 | Author(s): Y.W. Moon
- Abstract
- Presentation
Background:
Fibroblast growth factor receptor (FGFR) tyrosine kinase plays a crucial role in cancer cell growth, survival, and resistance to chemotherapy. FGFR1 amplification occurs at a frequency of 10-20% and is a novel druggable target in squamous cell carcinoma of the lung (SCCL). A number of FGFR-targeted agents are currently being developed in SCCL harboring FGFR alterations. The aim of the study is to evaluate the activity of selective FGFR inhibitors (AZD4547, BAY116387) and the mechanisms of intrinsic and acquired resistance to these agents in SCCL.
Methods:
The antitumor activity of AZD4547 and BAY116387 was screened in a panel of 12 SCCL cell lines, among which 4 cell lines harbored FGFR1 amplification. To investigate mechanisms of acquired resistance, FGFR1-amplified H1581 cells which were exquisitely sensitive to FGFR inhibitors, were exposed to AZD4547 or BAY116387 to generate polyclonal resistant clones (H1581-AR, H1581-BR). Characterization of these resistant clones was performed using receptor tyrosine kinase (RTK) array, immunoblotting and microarray. Migration and invasion assays were also performed.
Results:
Among 12 SCCL cell lines, two FGFR1-amplified cells, H1581 and DMS114, were sensitive to FGFR inhibitors (IC~50~<250 nmol/L). Compared with resistant cells, sensitive cells showed increased phosphorylation of FRS2 and PLC-γ, but decreased phosphorylation of STAT3. There was no noticeable difference in FGFR1-3 protein expression level between sensitive and resistant cells. Importantly, phosphorylation of ERK1/2 was significantly suppressed upon treatment of FGFR inhibitors only in sensitive cells, suggesting phospho-ERK1/2 as a pharmacodynamic marker of downstream FGFR signaling. RTK array and immunoblots demonstrated strong overexpression and activation of MET in H1581-AR and H1581-BR, in comparison to almost nil expression in parental cells. Four different SCCL cells with intrinsic resistance to FGFR inhibitors also showed intermediate to high MET expression, suggesting that MET may be involved in both intrinsic and acquired resistance to FGFR inhibitors. Gene-set enrichment analysis against KEGG database showed that cytokine-cytokine receptor interaction pathway was significantly enriched, with MET contributing significantly to the core enrichment, in H1581-AR and H1581-BR, as compared with parental cells. Stimulation with HGF strongly activated downstream FGFR signaling or enhanced cell survival in the presence of FGFR inhibitors in both acquired and intrinsic resistant cells. Quantitative PCR on genomic DNA and fluorescent in situ hybridization revealed MET amplification in H1581-AR, but not in H1581-BR. MET amplification led to acquired resistance to AZD4547 in H1581-AR by activating ERBB3. The combination of FGFR inhibitors with ALK/MET inhibitor, crizotinib, or small interfering RNA targeting MET synergistically inhibited cell proliferation in both H1581-AR and H1581-BR, whereas it resulted in additive effects in SCCL cells with intrinsic resistance to FGFR inhibitors. Acquisition of resistance to FGFR inhibitors not only led to a morphologic change, but also promoted migration and invasion of resistant clones via inducing epithelial to mesenchymal transition phenotype, as documented by a decrease in E-cadherin and an increase in N-cadherin and vimentin.
Conclusion:
MET activation is sufficient to bypass dependency on FGFR signaling and concurrent inhibition of these two pathways may be desirable when targeting FGFR-dependent SCCL.
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ORAL 06 - Next Generation Sequencing and Testing Implications (ID 90)
- Event: WCLC 2015
- Type: Oral Session
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:G. De Lima Lopes, V. Miller
- Coordinates: 9/07/2015, 10:45 - 12:15, Mile High Ballroom 1a-1f
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ORAL06.02 - Targeted Deep Sequencing of EGFR/KRAS/ALK-Negative Lung Adenocarcinoma Reveals Potential Therapeutic Targets (ID 622)
11:16 - 11:27 | Author(s): Y.W. Moon
- Abstract
- Presentation
Background:
Identification of clinically relevant molecular drivers in patient tumors is essential in selecting appropriate targeted therapy. Using next-generation sequencing (NGS) -based clinical cancer gene test, we performed genomic profiling of lung adenocarcinoma tumors.
Methods:
We collected formalin-fixed paraffin-embedded tumors from 41 lung adenocarcinoma patients whose tumors previously tested negative for EGFR/KRAS/ALK by conventional methods in an ongoing trial (NCT01964157). We performed hybridization capture of 4,557 exons from 287 cancer-related genes and 47 introns from 19 genes frequently rearranged in cancer (FoundationOne). Illumina HiSeq2000 platform was used to sequence to high uniform depth.
Results:
Figure 1Tumors were sequenced to a median coverage of 529x. Overall, we identified a total of 170 known and 492 unknown individual genomic alterations. The number of known alterations per sample was average of 3.8 alterations (range 0-10). Cancer genomes are characterized by 45% (77/170) non-synonymous base substitutions, 17% (29/170) insertions or deletions, 2% (4/170) splice site mutations, 20% (34/170) gene amplifications, 5% (8/170) homozygous loss and 5% (8/170) gene fusions. TP53 was the most commonly mutated gene (13%, n=10/77) among non-synonymous base substitutions, followed by KRAS (10%, n=8/77) and PIK3CA (8%, 6/77). Insertions or deletions commonly occurred TP53 (17%, 5/29) and ERBB2 (14%, 4/29), and splice site mutations occurred in TP53, INPP4B, ATR, and MAP2K4 (n=1 each). Among gene amplification, MDM2 amplification was the most frequent (12%, 4/34), followed by ERBB2 (8%, 3/34) and CDK4 (8%, 3/34) amplification. All 8 cases of homozygous loss were observed with CDKN2A and CDKN2B. Fusion genes were most commonly observed with RET (50%, n=4/8). Based on NCCN guidelines, actionable genomic alterations with a targeted agent were identified in 16 patients (39%) (BRAF mutation [n=1], EGFR mutation [n=7], ERBB2 mutation [n=4], MET amplification [n=1], KIF5B-RET rearrangement [n=2], CCDC6-RET rearrangement [n=1], and CD74-ROS1 rearrangement [n=1]). Nine out of all patients (22%) showed discordance in targetable alterations when compared between NGS and conventional non-NGS methods.
Conclusion:
Thirty-nine percent of lung adenocarcinoma wild type for EGFR/KRAS/ALK may harbor a genomic alteration revealed by NGS approach. These results highlight the importance of profiling lung adenocarcinomas using NGS in the clinic.
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