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A. Katz
Moderator of
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ORAL 21 - Biology - Moving Beyond the Oncogene to Oncogene-Modifying Genes (ID 118)
- Event: WCLC 2015
- Type: Oral Session
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 7
- Moderators:A. Katz, M.S. Tsao
- Coordinates: 9/08/2015, 10:45 - 12:15, Mile High Ballroom 4a-4f
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ORAL21.01 - Adaptive Survival Signaling in Oncogenic Fusion Kinase Addicted NSCLC (ID 864)
10:45 - 10:56 | Author(s): A. Vaishnavi, S.B. Keysar, A.T. Le, D.L. Aisner, L. Heasley, A. Jimeno, R.C. Doebele
- Abstract
Background:
Gene fusions involving the proto-oncogenes ALK, ROS1, RET and NTRK1 are established or potential drug targets in cancer. Although targeted kinase inhibitors induce significant tumor shrinkage, complete patient responses are rare, and it is from that residual tumor burden that drug resistant clones eventually emerge. We have previously shown a role for WT EGFR signaling in ROS1+ cancer cells and their drug resistant derivatives. We hypothesized that EGFR performs a similar role in cancer cells harboring other gene fusions.
Methods:
Fusion oncogene NSCLC cell lines were treated as described and analyzed through immunoblot analyses or fixed onto chamber slides and assayed using kinase-adaptor proximity ligation assays (PLA). FFPE from NSCLC patients treated at the University of Colorado Hospital were also analyzed using kinase-adaptor PLAs. Nu/nu mice were injected with fusion oncogene positive NSCLC cell lines, treated as described, and volumes were measured 3x/week. FFPE tumors from mice were analyzed using various immunohistochemical markers or kinase-adaptor PLAs.
Results:
Stimulation of NSCLC cells that harbor an oncogenic fusion with EGF not only increased downstream signaling, but also rapidly increased phosphorylation of the fusion kinase itself. Additionally, EGFR signaling can dictate the engagement of different downstream signaling effectors, diversifying the signaling and cell fate responses in certain cancer cells. Proximity ligation assays (PLA) were employed to visualize wild-type EGFR-GRB2 signaling complexes in NSCLC cells driven by an oncogenic fusion kinase. We observed two modes of EGFR-GRB2 complex formation, the first in unperturbed cells, and the second only when the fusion kinase was inhibited. The kinetics of the induction of EGFR-GRB2 signaling revealed EGFR can take over the signaling in these cells as quickly as 5 minutes, and this kinase inhibitor-induced rewiring can be reversed by simply washing out the drug, suggesting a preference for the fusion kinase in the signaling circuit of these cells. Analysis of fusion-positive patient samples acquired at the time of progressive disease from treatment with an oncogene targeted monotherapy revealed the presence of EGFR-GRB2 signaling complexes. Additional analyses of patient samples revealed evidence of potentially non-cell autonomous responses to these therapies that may enable the survival of cells that would otherwise be drug-sensitive. The combination of a fusion kinase inhibitor with anti-EGFR therapy provided superior blockage of EGFR and ALK signaling complexes, as well as improved reduction in tumor volume and prolonged survival in an ALK+ xenograft model.
Conclusion:
Collectively, these results demonstrate a previously unknown role for an unmutated kinase, EGFR, in modulating the oncogenic phenotype in cells addicted to oncogenic fusion kinases. The activation of the EGFR signaling pathway can quantitatively augment fusion kinase signaling, but also diversify it by regulating the engagement of alternate signaling effector proteins. This data provides evidence for a novel role for EGFR as an oncorequisite signaling partner in certain cancer cell populations that harbor an oncogenic fusion kinase. Combination therapy of a fusion kinase targeted inhibitor with anti-EGFR therapy may improve initial tumor cell killing, and delay or prevent the onset of drug resistance in these patient populations.
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ORAL21.02 - Landscape and Functional Significance of KRAS Co-Mutations in Lung Adenocarcinoma (LUAC) (ID 3224)
10:56 - 11:07 | Author(s): F. Skoulidis, L. Byers, P. Tong, L. Diao, W. Denning, J. Gudikote, Y. Fan, V. Papadimitrakopoulou, J.G. Izzo, C. Behrens, H. Kadara, E.R. Parra Cuentas, J. Rodriguez-Canales, D.L. Gibbons, J.N. Weinstein, L. Girard, J. Minna, J. Wang, I.I. Wistuba, J.V. Heymach
- Abstract
- Presentation
Background:
The biological heterogeneity of KRAS-mutant LUAC represents a major impediment to the successful implementation of targeted therapeutic strategies for this clinically challenging group of lung cancer patients. Through integrative, multi-platform analysis of large scale omics data we recently identified three major subsets of KRAS-mutant LUAC defined on the basis of co-occurring genomic alterations in STK11/LKB1 (KL subgroup), TP53 (KP) and CDKN2A/B (KC), the latter coupled with low expression of the TTF1 transcription factor. We further demonstrated subset-specific molecular dependencies, patterns of immune system engagement and therapeutic vulnerabilities. Here, we extend these findings through comprehensive analysis of a wide panel of KRAS co-mutations and assess the impact of key co-mutations on facets of the malignant phenotype including flux through the MAPK and PI3K/AKT pathways and heterotypic interactions with the host immune system.
Methods:
Our datasets consisted of 431 tumors from TCGA (122 KRAS-mutant), 41 additional chemo-naive KRAS-mutant LUACs (PROSPECT dataset) and 36 platinum-refractory KRAS-mutant LUACs from the BATTLE-2 clinical trial. Significant KRAS co-mutations were identified on the basis of a P value threshold of ≤0.05 (Fisher’s exact test) coupled with a baseline prevalence of ≥3%. RNASeq data were downloaded directly from the TCGA site. Expression profiling of PROSPECT tumors was performed using the Illumina Human WG-6 v3 BeadChip Array whereas BATTLE-2 tumors were profiled using the GeneChipâHuman Gene 1.0 ST Array from Affymetrix. Generation of MAPK and PI3K proteomic scores, based on Reverse Phase Protein Array (RPPA) data, has been previously reported.
Results:
Our analysis identified somatic mutations in 31 genes as significantly co-mutated with KRAS in LUAC samples. Among them, co-mutations in STK11/LKB1 (P=0.00011) and ATM (P=0.0004) predominated. Somatic mutations in ERBB4 (P=0.0059), encoding a member of the ErbB family of receptor tyrosine kinases and MAP3K4 (P=0.0017) were also enriched in KRAS-mutant LUAC. We assessed the impact of KRAS co-mutations on the amplitude and directionality of signaling downstream of mutant KRAS using the proteomic “MAPK score“ and “PI3K score” as surrogates of effector pathway activation. Interestingly, co-mutations in ERBB4 were associated with significantly suppressed flux through the MAPK pathway (P=0.0024, t-test). Somatic mutations in other genes, including CAMSAP2, were associated with suppressed signaling through both the MAPK (P=0.00876, t-test) and PI3K-AKT (P=0.0032, t-test) cascades. Finally, within KRAS-mutant tumors, co-mutations in NLRC5, a master transcriptional regulator of MHC Class I molecules were associated with reduced mRNA expression of several of its classical target genes. In addition, low mRNA expression of NLRC5 correlated strongly with reduced expression of key components of the antigen presentation pathway across multiple independent datasets of chemotherapy naïve and platinum refractory KRAS-mutant tumors and cell lines. Thus, in addition to cell autonomous effects, co-mutations can also impinge on the reciprocal relationship between malignant cells and their immune microenvironment.
Conclusion:
Our work identifies a compendium of KRAS co-mutations that impact classical and emerging cancer hallmarks, including evasion of the host immune response. Systematic interrogation of the functional impact of prevalent KRAS co-mutations is essential for the development of personalized treatment approaches for this heterogeneous group of tumors.
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ORAL21.03 - KEAP1-Mutations and NFE2L2-Mutations in Patients with Non-Small Cell Lung Cancer (NSCLC) (ID 2792)
11:07 - 11:18 | Author(s): R. Frank, M. Scheffler, S. Michels, A. Eisert, R.N. Fischer, K. König, S. Merkelbach-Bruse, M.H. Serke, Y. Ko, U. Gerigk, T. Geist, L.C. Heukamp, R. Büttner, J. Wolf
- Abstract
- Presentation
Background:
Mutations in genes of the KEAP1-NFE2L2 pathway in patients with NSCLC are associated with an increased tumor growth, resistance towards cytostatic drugs and reduced survival rates. KEAP1 suppresses NFE2L2 under physiological conditions. Oxidative stress or electrophiles cause NFE2L2 to stabilize and translocate to the nucleus, resulting in transcription of various cytoprotective genes. Mutations in KEAP1 and NFE2L2 are described for diverse tumor entities and often cause an increased level of NFE2L2 leading to resistance of cancer cells against anti-cancer drugs and irradiation. This study was performed to characterize KEAP1-mutated and NFE2L2-mutated NSCLC clinically and genetically.
Methods:
Tumor tissue collected from 446 patients within a regional screening network was analysed for KEAP1 mutations and NFE2L2 mutations using next-generation sequencing (NGS). Clinical, pathological and genetic characteristics of these patients are described and compared with a control group of patients without KEAP1 mutation and without NFE2L2 mutation.
Results:
So far, we identified 33 patients with KEAP1 mutations. Among these we found 34 different mutations, of which the majority was not previously described. KEAP1 mutations were not restricted to a special exon. In 30 patients (90.9%), additional driver aberrations in KRAS, EGFR, FGFR1, FGFR3, STK11, ALK, DDR2, HRAS, BRAF, PIK3CA, PTEN, NFE2L2, EP300, TSC1, CREBBP, NRAS, MET and Her2 could be detected, as well as mutations and polymorphisms in TP53. KEAP1 mutations occurred in both genders (male/female ratio 3/1), in squamous-cell carcinoma (36.4%) and adenocarcinoma (60.6%) and were significantly associated with smoking. We also identified 26 patients with NFE2L2 mutations. Among these we found 15 different mutations, of which W24R and E79K were the most common. In 20 patients (76.9%) additional driver aberrations were detected. NFE2L2 mutations occurred in squamous-cell carcinoma (69.2%) and adenocarcinoma (23.1%) and were significantly associated with smoking as well. NFE2L2 mutations also occurred in both genders with 61.5% male and 38.5% female. Two patients had both a KEAP1 mutation and a NFE2L2 mutation.
Conclusion:
Our data suggest a role of KEAP1-mutations and NFE2L2-mutations as a cofactor in addition to classical driver mutations underlying the malignant phenotype of lung cancer cells. So far, this is the largest cohort of patients with KEAP1-mutations and NFE2L2-mutations analysed and described. Further survival and treatment analyses will reveal the role of these mutations for the outcome of these patients.
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ORAL21.04 - Discussant for ORAL21.01, ORAL21.02, ORAL21.03 (ID 3354)
11:18 - 11:28 | Author(s): D. Morgensztern
- Abstract
- Presentation
Abstract not provided
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ORAL21.05 - p53/KRAS Mutation Status Does Not Predict Sensitivity to Chemotherapy in NSCLC PDXs (ID 2459)
11:28 - 11:39 | Author(s): C. Mascaux, L. Dhont, P. Tomasini, N. Pham, M. Li, Y. Wang, E. Stewart, T.K. Waddell, M.S. Tsao, F. Shepherd
- Abstract
- Presentation
Background:
The LACE-Bio group assessed the prognostic and predictive values of KRAS and p53 mutations in 1543 completely resected non-small cell lung cancer (NSCLC) tumors. The predictive value of combined KRAS/p53 mutations for survival benefit from adjuvant chemotherapy was evaluated on 49 patients and chemotherapy was deleterious in this group compared to observation (HR 2.49 CI 95% [1.10 – 5.66], p=0.03). Patients with tumors harboring combined KRAS/p53 mutations had a worse outcome when treated with adjuvant chemotherapy compared patient with double wild type (WT) tumors (HR 3.03 (95% CI [1.29 – 7.15], p=0.01, interaction p=0.06). We have compared the chemo-sensitivity of patient derived xenografts (PDXs) with double p53/KRAS mutations, single p53, single KRAS mutation or double WT. 0
Methods:
Surgically resected early stage lung adenocarcinomas (ADC) were implanted into non-obese diabetic severe combined immune deficient (NOD-SCID) mice. Fourteen lung ADC PDXs with various p53/KRAS status were revived and implanted: 11 engrafted and were expanded for comparison of treatment vs control. For each model, 6 replicates were included in treatment and control arms. Chemotherapy (cisplatin 3 mg/kg and vinorelbine 7 mg/kg intraperitoneally weekly) was initiated in the PDXs at tumor volumes of 150 mm[3].
Results:
Four models were p53/KRAS double mutant, 4 p53 mutant, 2 KRAS mutant and 1 double WT. The 4 double mutant PDXs responded to chemotherapy, 2 with reduced (SD) and 2 inhibited (PR) growth. Among the 4 PDXs with p53 mutation only, 2 responded (1 PR and 1 SD) and 2 were resistant. Among the 2 PDXs with KRAS mutation only, 1 had a complete response, but relapsed at treatment arrest and 1 achieved PR. The double WT PDX was highly sensitive to chemotherapy (PR) but also relapsed at treatment arrest.
Conclusion:
Among these 11 PDXs, the p53/KRAS mutation status did not predict chemo-sensitivity to cisplatin/vinorelbine, one of the most active adjuvant chemotherapy regimens in NSCLC. As these PDXs were molecularly profiled, we currently are investigating other biomarkers that might predict their sensitivity or resistance to chemotherapy.
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- Abstract
Background:
Hippo signaling is actively involved in adult tissue homeostasis and cell fate determination. Previous studies have linked the activation of YAP (the major downstream effector of Hippo pathway) with LKB1 deficiency. Here, we characterize the function of YAP in the progression and phenotypic plasticity of LKB1-deficient lung tumors and decipher the detailed mechanisms underlying those process.
Methods:
Through integrative studies on human lung cancer specimens and lung cancer mouse models, we investigate the distinct role of YAP on lung cancer malignant progression and phenotypic transition. Furthermore, we uncover the detailed mechanisms by cell line based works together with biochemistry and molecular biology methods.
Results:
The oncogenic role of YAP in malignant progression of Lkb1-deficient lung adenocarcinoma Using distinct lung cancer mouse models, we show that ectopic expression of YAP in Type II alveolar epithelial cells results in hyperplasia in the lung. YAP expression significantly accelerates lung adenocarcinoma (ADC) malignant progression in Kras[G12D] mice whereas YAP deletion dramatically delays the process in Lkb1[L/L]/Kras[G12D] mice. Further mechanistic investigations have revealed that the delayed progression in Lkb1-deficient ADC with YAP ablation attribute to the downregulation of the inhibitor of apoptosis protein, Survivin. The inhibitory role of YAP in phenotypic transition from adenocarcinoma to squamous cell carcinoma We have previously shown LKB1 inactivation confers lung adenocarcinoma with strong plasticity to progressively change the cell fate and transit to squamous cell carcinoma with unknown mechanism. Here, we find that ectopic YAP overexpression dramatically inhibits ADC to SCC transdifferentiation whereas knockdown of YAP conversely accelerates the transition process. YAP is initially activated by LKB1 loss in ADC, leading to ZEB2 up-regulation in ADC cells, which binds to DNp63 gene promoter to repress DNp63 transcription. During the transition process, extracellular matrix (ECM) depletion in ADC inactivates YAP, thus relieves ZEB2 mediated default repression on DNp63 transcription in ADC, leading to the initiation of squamous differentiation program. Functionally, p63 ectopic expression significantly rescues the inhibitory effect of YAP upon SCC transdifferentiation.
Conclusion:
Our findings uncover the two faces of YAP in lung tumor malignant progression and phenotypic plasticity. YAP is an essential mediator of malignant progression of Lkb1-deficient lung ADC via regulating Survivin whereas an important barrier for lung cancer transdifferentiation through ZEB2 dependent DNp63 repression. Those works shed light on the fundamental role of YAP in regulating cancer progression and lineage phenotypic transition in LKB1 deficient lung tumors, which might help future development of better therapeutic strategies.
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ORAL21.07 - Discussant for ORAL21.05, ORAL21.06 (ID 3355)
11:50 - 12:00 | Author(s): F. Grossi
- Abstract
- Presentation
Abstract not provided
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