EGFR-mutant Cell Research Articles

Abstract 1101: Intercellular transfer of exosomal wild type EGFR triggers osimertinib resistance in non-small cell lung cancer

Abstract Epidermal growth factor receptor (EGFR)-mutated lung cancer constitutes a major subgroup of non-small cell lung cancer (NSCLC) and osimertinib is administrated as first-line treatment. However, most patients with osimertinib treatment eventually relapse within one year. The underlying mechanisms of osimertinib resistance remain largely unexplored. In this study, we found that osimertinib resistance could be triggered by the intercellular transfer of wild type EGFR protein encapsulated in exosomes from osimertinib-insensitive NSCLC cells to EGFR-mutated osimertinib-sensitive cells and then the activation of PI3K/AKT and MAPK signaling pathways both in vitro and in vivo. Importantly, osimertinib significantly increased the formation and secretion of exosomes linked to the upregulation of a Rab GTPase (RAB17). These results demonstrate the intercellular transfer of exosomal wild type EGFR maybe a novel resistant mechanism of osimertinib. These findings provide a proof of concept for targeting exosomes to prevent and reverse the osimertinib resistance. Citation Format: Shaocong Wu, Min Luo, Kenneth K. To, Jianye Zhang, Chaoyue Su, Hong Zhang, Sainan An, Fang Wang, Da Chen, Li-Wu Fu. Intercellular transfer of exosomal wild type EGFR triggers osimertinib resistance in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1101.

Abstract 2300: Overcoming TKI-resistance in NSCLC using SphK2 inhibitors

Abstract In 2020, 228,820 lung cancer cases and 135,720 deaths have been anticipated. NSCLC is currently treated with Tyrosine Kinase Inhibitors (TKIs) such as Erolitinib (ER; second generation) and Osimertinib (OR; third generation). However, patients often develop resistance to these drugs overtime. This acquired resistance to TKIs is due to a secondary T790M mutation in the kinase domain which could be responsible for inducing Epithelial Mesenchymal Transition (EMT). EMT is a vital process in development of metastasis and occurs, by downregulation of E-cadherin, and upregulation of proteins like N-cadherin and vimentin. Therefore, it is imperative to find other molecularly targeted therapies to combat TKI resistance. Sphingosine kinase (SphK) is a type of lipid kinase that phosphorylates sphingosine to sphingosine-phosphates. There are two functional SphK isoforms (SphK1 and SphK2) that have been identified and characterized in mammalian cells. As a member of the SphK family, SphK2 activity can be stimulated by a series of cytokines such as EGF and VEGF, and acts as an oncogenic enzyme in tumor cells. Overexpression of SphK2 has been demonstrated in many cancer types and is closely related with cancer progression and the poor survival of patients. Currently minimal studies have been done on lung cancer and SphK2. This study investigated the roles of SphK2 in OR-resistant wild-type EGFR H2170 and H358, EGFR-mutated and TKI-sensitive H3255 cells (L858R mutation), and EGFR mutated TKI-resistant H1975 cells (L858R and T790M mutation). The modulation of EMT biomarkers was determined by qPCR. Key EMT regulators such as vimentin and N-cadherin were upregulated by 2.5 and 1.5-fold, respectively, while E-cadherin was downregulated by 1.5-fold. Immunofluorescence studies with Vimentin showed that H1975OR cells were elongated and have a mesenchymal phenotype compared to the H3255OR and their respective parental counterparts. MTT studies done using inhibitors of SphK2 in NSCLC OR-resistant cells showed a 3.0-fold decrease in cell viability in comparison to a 2.0-fold decrease in their parental counterparts. In wound closure assays at 24 hours the wound closure was 1.5-fold less in cells treated with SphK2 inhibitor as compared to parental cells treated with SphK2 inhibitors. Currently studies are being done to determine expression of SphK2 in late and early stage NSCLC tumors. In conclusion SphK2 was found to be a crucial positive regulator of different modes of cell migration and a key biomarker in combating TKI-resistance in NSCLC. Citation Format: Nabiha Haleema Khan, Neelu Puri. Overcoming TKI-resistance in NSCLC using SphK2 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2300.

Abstract 1107: Precision phosphoproteomic analysis in Chr22q11.2 amplified NSCLC cells reveals distinct signaling corruption and response to Aurora kinase B inhibition

Abstract Background: NSCLC cells carrying EGFR mutations can gain resistance to cognate TKIs through amplification of Chr22q11.2 (Chr22amp), a chromosome segment containing CRKL. This also specifically associates with exquisite sensitivity to inhibitors of Aurora Kinase B (AZD2811), potentially mediated by other Chr22 genes. Furthermore, a phenotypic rewiring occurs in the response to AZD2811, from a senescent polyploidy in wildtype (WT) cells to apoptosis in Chr22amp cells. Here, we aimed to elucidate the underlying signaling alterations in this background by phosphoproteomic pathway analysis. Methods: The EGFR mutant cell line PC9 and 8 TKI resistant derivatives were profiled (4 Chr22amp and 4 WT). Kinetics of response to AZD2811 (100nM) and osimertinib (160 nM) were identified by flow cytometry. Samples (n=3) were prepared for phosphoproteomics, after 6, 24, and 48 h AZD2811 and 1 h osimertinib, with time matched controls. Cells were washed and lysed in urea, then digested with trypsin. Phosphorylated peptides were enriched with TiO2 and analyzed by Orbitrap LC-MS/MS. Computational analyses quantified peptides across samples. KScanTM bioinformatics identified differential phosphopeptides between Chr22amp and WT to determine kinase substrate profiles by KSEA, putative downstream targets (PDT) and differential compound target activity markers (CTAM). Results: Single cell time-course analysis of phenotypic response to AZD2811 in Chr22amp cells showed that >60% of cells become Annexin V+ by 48 h post-treatment. We took earlier timepoints of 6, 24 and 48 h post treatment. We focused the phosphoproteomic analysis on three comparisons of Chr22amp amplified cells to: 1) the basal signaling state compared to WT; 2) the signaling response to osimertinib in parental PC9; and 3) the altered kinetics of signaling in response to AZD2811 compared to WT. At the basal level, Chr22amp had CK1e, CDK2, p38a substrates differentially enriched, and MTOR inhibitor and Aurora B inhibitor modulated sites (p<10-3). The response to osimertinib was largely differential in the maintenance of ERK1/2 signaling to P90RSK1 but not MEK1 in Chr22amp cells. In cells treated with AZD2811, alterations in signaling were associated with Aurora B in all cells as expected. However in amplified cells, we observed key differences at 24h such in cell death and metabolic processes in specific hierarchical clusters of temporally modulated sites, underpinned by relative down regulation of multiple signaling nodes such as ARAF (z = 4.87, p<10-2), ERN1 (z = 4.56, p<10-2), and CDK2 (z = 4.30, p<10-2). Conclusions: Here, we identified significant pathway deregulation in Chr22amp cells that subverted EGFR inhibition and enhanced sensitivity to AZD2811. Intriguingly, we detected enhanced Aurora B activity in Chr22amp cells at basal levels, and surprising impact of AZD2811 on the EGFR pathway. Citation Format: Arran Dokal, Jordi Bertran-Alamillo, Edmund Wilkes, Hilary Lewis, Ana Gimenez-Capitan, Calum Greenhalgh, Ruth Osuntola, Maruan Higazi-Vega, Shona Ellison, Vinothini Rajeeve, Giulia Fabbri, Urszula Polanska, J. Elizabeth Pease, Pedro Rodriguez-Cutillas, Jelena Urosevic, Miguel Angel Molina-Vila, David Britton, Jon Travers. Precision phosphoproteomic analysis in Chr22q11.2 amplified NSCLC cells reveals distinct signaling corruption and response to Aurora kinase B inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1107.

Abstract 951: Evolution of antibody titers, growth factor levels and in vitro activity in the sera of patients enrolled in the EPICAL trial of afatinib combined with anti-EGF vaccination

Abstract Background: We have recently demonstrated that antibodies generated by vaccination (anti-EGFVacAbs) potentiate the effects of EGFR TKIs in epidermal growth factor receptor mutant (EGFR-mut) non-small cell lung cancer (NSCLC) cells growing in vitro and prevent the emergence of resistance to EGFRTKIs (1). Based on these preclinical results we have started the Epical Phase Ib clinical trial(NCT03623750), testing anti-EGF vaccination in combination with EGFR TKI in advanced EGFR-mut NSCLC patients. Methods: The EPICAL trial is a Multicenter, Open-Label, Exploratory Phase Ib Clinical Study in which 23 patients have been enrolled. Anti-EGF VacAbs is a vaccine for intramuscular administration that is designed to be used in conjunction with standard of care treatment which, in this study, is afatinib. Blood samples have been collected at baseline and every three months and sent to a central laboratory. The presence of EGFR mutations has been determined on purified DNA by 5′-nuclease real-time PCR (Taqman®) assay in presence of PNA. All the serum samples have been analyzed by ELISA to determine the levels of EGF, TGFα, HGF and GAS6, together with anti-EGF antibody titers. Sera of patients were added to EGFR-mutant cell lines growing in vitro and Western blot was used to analyze EGFR, AKT andERK activation. Results: Median EGF levels in the sera of enrolled patients was 179.5 pg/mL at baseline and no anti-EGFantibodies were detected. Three months after first immunization, median serum EGF levels decreased to30.8 pg/mL (p=0.0008) while the anti-EGF vaccination titers increased to 1:6000 (p=0.0012). Anti-EGF titers remained high and EGF levels low in the patient's sera for the duration of the trial. Regarding serum TGFα and HGF levels baseline were 19.4 pg/mL and 861.2 pg/mL, respectively, and after three months dropped to 7.9 pg/mL (p=0.0037) and 341.3 pg/mL (p=0.0259). In EGFR-mutant cell lines in culture, the activation of the EGFR, AKT or ERK was abrogated by the sera of immunized patients. Conclusions: Anti-EGF vaccination induces high anti-EGF antibody titers and effectively reducing the levels of EGF and other growth factors in the blood of advanced NSCLC patients. 1J Thorac Oncol. 2018 Sep;13(9):1324-1337. Citation Format: Silvia Garcia-Roman, Jordi Codony, Miguel Angel Molina-Vila, Nuria Jordana-Ariza, Beatriz Garcia, Monica Garzon, Clara Mayo de las Casas, Maria Jose Catalan, Andres Aguilar, Santiago Viteri, Andres F. Cardona, Delvys Rodríguez, Manuel Cobo, Noemi Reguart, Erik d'Hondt, Rafael Rosell. Evolution of antibody titers, growth factor levels and in vitro activity in the sera of patients enrolled in the EPICAL trial of afatinib combined with anti-EGF vaccination [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 951.

Membrane-Associated RING-CH 8 Functions as a Novel PD-L1 E3 Ligase to Mediate PD-L1 Degradation Induced by EGFR Inhibitors.

Expression of programmed death-ligand 1 (PD-L1) on cancer cells is a critical mechanism contributing to immunosuppression and immune escape. PD-L1 expression may also affect therapeutic outcomes of epidermal growth factor receptor (EGFR)-targeted therapy (e.g., with osimertinib/AZD9291) against EGFR-mutant non-small cell lung cancers (NSCLC) and can even be altered during the treatment albeit with largely undefined mechanisms. This study primarily focuses on elucidating the mechanism by which osimertinib induces PD-L1 degradation in addition to validating osimertinib's effect on decreasing PD-L1 expression in EGFR-mutant NSCLC cells and tumors. Osimertinib and other EGFR inhibitors effectively decreased PD-L1 levels primarily in EGFR-mutant NSCLCs and xenografted tumors. Osimertinib not only decreased PD-L1 mRNA expression, but also prompted proteasomal degradation of PD-L1 protein, indicating both transcriptional and posttranslational mechanisms accounting for osimertinib-induced reduction of PD-L1. Knockdown of β-TrCP or inhibition of GSK3 failed to prevent PD-L1 reduction induced by osimertinib. Rather, knockdown of membrane-associated RING-CH 8 (MARCH8) that encodes a membrane-bound E3 ubiquitin ligase rescued osimertinib-induced PD-L1 reduction. Furthermore, manipulation of MARCH8 expression accordingly altered PD-L1 degradation rate. Critically, MARCH8 interacted with PD-L1 through its N-terminal region and also ubiquitinated PD-L1 in cells. Collectively, these results strongly suggest that MARCH8 is a previously undiscovered E3 ubiquitin ligase responsible for PD-L1 degradation including osimertinib-induced PD-L1 degradation, establishing a novel connection between MARCH8 and PD-L1 regulation. IMPLICATIONS: This study has demonstrated a previously undiscovered function of MARCH8 in mediating PD-L1 degradation induced by EGFR inhibitors in EGFR-mutant NSCLC cells, establishing a novel connection between MARCH8 and PD-L1 regulation.

EGFR-Mutated Squamous Cell Lung Cancer and Its Association With Outcomes.

BackgroundThe therapeutic efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in advanced EGFR-mutant lung squamous cell carcinoma (SCC) patients remains uncertain. Furthermore, the factors underlying the responsiveness have not been fully investigated. We therefore investigated the link between genomic profiles and EGFR-TKI efficacy.Material and MethodsWe consecutively enrolled stage IV, EGFR-mutant, and EGFR-TKI–treated patients with SCC. Patients with EGFR wild-type lung SCC and EGFR-mutant lung adenocarcinoma were consecutively enrolled as controls, and next-generation sequencing (NGS) was performed.ResultsIn total, 28 EGFR-mutant lung SCC, 41 EGFR-mutant lung adenocarcinoma, and 40 EGFR wild-type lung SCC patients were included. Among the patients with EGFR mutations, shorter progression-free survival (PFS) was observed in SCC compared to adenocarcinoma (4.6 vs. 11.0 months, P<0.001). Comparison of the genomic profiles revealed that EGFR-mutant SCC patients had similar mutation characteristics to EGFR-mutant adenocarcinoma patients, but differed from those with EGFR wild-type SCC. Further exploration of EGFR-mutant SCC revealed that mutations in CREBBP (P = 0.005), ZNF217 (P = 0.016), and the Wnt (P = 0.027) pathway were negatively associated with PFS. Mutations in GRM8 (P = 0.025) were associated with improved PFS.Conclusions EGFR-mutant lung SCC has a worse prognosis than EGFR-mutant adenocarcinoma. Mutations in other genes, such as CREBBP, ZNF217, GRM8, or Wnt that had implications on PFS raise the possibility of understanding mechanisms of resistance to EGFR-TKI in lung SCC, which will aid identification of potential beneficial subgroups of patients with EGFR-mutant SCCs receiving EGFR-TKIs.

Effectiveness of osimertinib plus chemotherapy and avastin for untreated EGFR-mutated advanced non-small cell lung cancer.

e21178 Background: Osimertinib is recommended as a novel first-line standard treatment for advanced Non-Small-Cell Lung Cancer (NSCLC) patients with EGFR mutation. However, there are also patients with concurrent mutation or/and metastases have limited benefits. According to the current remission rate, regression depth and PFS data, the main mechanism of the benefit of combined anti-angiogenesis or chemotherapy is to reduce tumor load and heterogeneous reserve to a greater extent, so as to extend the remission time, that is, to delay the occurrence of drug resistance to extend PFS. This prospective study aims to investigate the efficacy and safety of Osimertinib plus chemotherapy and Avastin for Untreated EGFR-Mutated advanced NSCLC. Methods: The study enrolled 22 patients diagnosed with untreated advanced NSCLC and tested with EGFR mutation, who received osimertinib ( 80mg QD) plus pemetrexed (500mg/m2), cisplatin (75mg/m2) and bevacizumab (7.5mg/kg) for 6 cycles, then maintained with osimertinib/pemetrexed/bevacizumab. The primary endpoint was progression free survival (PFS). The secondary endpoint was objective response rate (ORR). Treatment was continued until disease progression and the tumor response was determined according to the Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1. The toxicity was determined according to CTCAE 4.0. Results: From February, 2018 to July, 2020, 22 patients enrolled. All the patients were evaluated and showed partial response(PR) when make efficacy evaluation at the first time. The target lesions reduction were shown. The average reduction is 48%, ranged from 32% of Pt12 to 71% of Pt11. Up to January, 2021, all the patients are still under the treatment. Especially for Pt7 who has already benefited from the treatment protocol by 35months. The toxicities associated with this protocols were manageable. Only 1 patient was 3/4-grade Anemia, 1 patient was 3/4-grade Diarrhea and 3 patients was 3/4-grade Lymphopenia. Conclusions: Osimertinib in combination with chemotherapy and Bevacizumab. exhibits superior activity and generally manageable toxicities for the naive advanced NSCLC patients with EGFR mutant, especially for the patients with concurrent mutation or/and metastases. It may provide a new and effective therapy strategy for them, but large sample and additional clinical trials are also needed.

A tyrosine kinase inhibitor-induced interferon response positively associates with clinical response in EGFR-mutant lung cancer

Tyrosine kinase inhibitors (TKIs) targeting EGFR-mutant lung cancers promote a range of tumor regression responses to yield variable residual disease, a likely incubator for acquired resistance. Herein, rapid transcriptional responses induced by TKIs early in treatment that associate with the range of patient responses were explored. RNAseq was performed on EGFR mutant cell lines treated in vitro with osimertinib and on tumor biopsies of eight EGFR mutant lung cancer patients before and after 2 weeks of TKI treatment. Data were evaluated for gene expression programs altered upon TKI treatment. Chemokine and cytokine expression were measured by ELISA and quantitative RT-PCR. IκB Kinase (IKK) and JAK-STAT pathway dependence was tested with pharmacologic and molecular inhibitors. Tumor sections were stained for the T-cell marker CD3. Osimertinib stimulated dynamic, yet wide-ranging interferon (IFN) program regulation in EGFR mutant cell lines. IL6 and CXCL10 induction varied markedly among the EGFR mutant cell lines and was sensitive to IKK and JAK-STAT inhibitors. Analysis of matched patient biopsy pairs revealed marked, yet varied enrichment of IFN transcriptional programs, effector immune cell signatures and T-cell content in treated tumors that positively correlated with time to progression in the patients. EGFR-specific TKIs induce wide-ranging IFN response program activation originating within the cancer cell. The strong association of IFN program induction and duration of clinical response indicates that the TKI-induced IFN program instructs variable recruitment and participation of immune cells in the overall therapeutic response.

Weekly osimertinib dosing prevents EGFR mutant tumor cells destined to home mouse lungs

The recently conducted ADAURA trial concludes daily dosing of adjuvant osimertinib, a third-generation EGFR tyrosine kinase inhibitor (TKI), improves disease-free survival with stage IB/II/IIIA EGFR -mutated non-small cell lung cancer patients in comparison to placebo. We have developed a preclinical orthotopic mouse model, using luciferase tagged lung adenocarcinoma cells harboring EGFR TKI sensitive exon 19 deletion to model and extend trial implications comparing a weekly vs daily dosing outcome of osimertinib to a first-generation TKI- erlotinib. We find that 100% of mice in both the groups receiving osimertinib daily or weekly before injection of cells show a complete absence of homing of cells in mice's lungs from day three until day 18 post-injection of cells. On the other hand, 25% and 75% of mice receiving erlotinib daily and weekly before injecting cells show homing of cells to the lungs. The tumors observed in the lungs, when dissected at day 30, confirmed the colonization of the injected cells homing to the organ. Thus, our study establishes the efficacy of pretreatment with osimertinib in reducing tumor cells' homing to mouse lungs in an in vivo mouse model.

A Model-Strengthened Imaging Biomarker for Survival Prediction in EGFR-Mutated Non-small-cell Lung Carcinoma Patients Treated with Tyrosine Kinase Inhibitors.

Non-small-cell lung carcinoma is a frequent type of lung cancer with a bad prognosis. Depending on the stage and genomics, several therapeutical approaches are used. Tyrosine Kinase Inhibitors (TKI) may be successful for a time in the treatment of EGFR-mutated non-small cells lung carcinoma. Our objective is here to introduce a survival assessment as their efficacy in the long run is challenging to evaluate. The study includes 17 patients diagnosed with EGFR-mutated non-small cell lung cancer and exposed to an EGFR-targeting TKI with 3 computed tomography (CT) scans of the primary tumor (one before the TKI introduction and two after). An imaging biomarker based on evolution of texture heterogeneity between the first and the third exams is derived and computed from a mathematical model and patient data. Defining the overall survival as the time between the introduction of the TKI treatment and the patient death, we obtain a statistically significant correlation between the overall survival and our imaging marker ([Formula: see text]). Using the ROC curve, the patients are separated into two populations and the comparison of the survival curves is statistically significant ([Formula: see text]). The baseline exam seems to have a significant role in the prediction of response to TKI treatment. More precisely, our imaging biomarker defined using only the CT scan before the TKI introduction allows to determine a first classification of the population which is improved over time using the imaging marker as soon as more CT scans are available. This exploratory study leads us to think that it is possible to obtain a survival assessment using only few CT scans of the primary tumor.

Single Living Cell Analysis Nanoplatform for High-Throughput Interrogation of Gene Mutation and Cellular Behavior.

The genetic heterogeneities in cancer cells pose challenges to achieving precise drug treatment in a widely applicable manner. Most single-cell gene analysis methods rely on cell lysis for gene extraction and identification, showing limited capacity to provide the correlation of genetic properties and real-time cellular behaviors. Here, we report a single living cell analysis nanoplatform that enables interrogating gene properties and drug resistance in millions of single cells. We designed a Domino-probe to identify intracellular target RNAs while releasing 10-fold amplified fluorescence signals. An on-chip addressable microwell-nanopore array was developed for enhanced electro-delivery of the Domino-probe and in situ observation of cell behaviors. The proof-of-concept of the system was validated in primary lung cancer cell samples, revealing the positive-correlation of the ratio of EGFR mutant cells with their drug susceptibilities. This platform provides a high-throughput yet precise tool for exploring the relationship between intracellular genes and cell behaviors at the single-cell level.

Alterations in the Global Proteome and Phosphoproteome in Third Generation EGFR TKI Resistance Reveal Drug Targets to Circumvent Resistance.

Lung cancer is the leading cause of cancer mortality worldwide. The treatment of patients with lung cancer harboring mutant EGFR with orally administered EGFR tyrosine kinase inhibitors (TKI) has been a paradigm shift. Osimertinib and rociletinib are third-generation irreversible EGFR TKIs targeting the EGFR T790M mutation. Osimertinib is the current standard of care for patients with EGFR mutations due to increased efficacy, lower side effects, and enhanced brain penetrance. Unfortunately, all patients develop resistance. Genomic approaches have primarily been used to interrogate resistance mechanisms. Here we characterized the proteome and phosphoproteome of a series of isogenic EGFR-mutant lung adenocarcinoma cell lines that are either sensitive or resistant to these drugs, comprising the most comprehensive proteomic dataset resource to date to investigate third generation EGFR TKI resistance in lung adenocarcinoma. Unbiased global quantitative mass spectrometry uncovered alterations in signaling pathways, revealed a proteomic signature of epithelial-mesenchymal transition, and identified kinases and phosphatases with altered expression and phosphorylation in TKI-resistant cells. Decreased tyrosine phosphorylation of key sites in the phosphatase SHP2 suggests its inhibition, resulting in subsequent inhibition of RAS/MAPK and activation of PI3K/AKT pathways. Anticorrelation analyses of this phosphoproteomic dataset with published drug-induced P100 phosphoproteomic datasets from the Library of Integrated Network-Based Cellular Signatures program predicted drugs with the potential to overcome EGFR TKI resistance. The PI3K/MTOR inhibitor dactolisib in combination with osimertinib overcame resistance both in vitro and in vivo. Taken together, this study reveals global proteomic alterations upon third generation EGFR TKI resistance and highlights potential novel approaches to overcome resistance. SIGNIFICANCE: Global quantitative proteomics reveals changes in the proteome and phosphoproteome in lung cancer cells resistant to third generation EGFR TKIs, identifying the PI3K/mTOR inhibitor dactolisib as a potential approach to overcome resistance.

Real-World Treatment Patterns, Epidermal Growth Factor Receptor (EGFR) Testing and Outcomes in EGFR-Mutated Advanced Non-small Cell Lung Cancer Patients in Belgium: Results from the REVEAL Study.

BackgroundTreatment of patients with epidermal growth factor receptor-mutated (EGFRm) non-small cell lung cancer (NSCLC) continues to evolve expeditiously.ObjectivesThis retrospective study investigated real-world treatment patterns and EGFR mutation testing in patients with EGFRm advanced NSCLC in Belgium.MethodsData were extracted from medical records of adults diagnosed with EGFRm locally advanced/metastatic NSCLC between 1 September 2015 and 31 December 2017. Patients were followed retrospectively from diagnosis until 1 September 2018, end of clinical activity or death. Data on demographics, patient outcomes and disease characteristics, treatment patterns and EGFR mutation testing at diagnosis and progression were analyzed descriptively.ResultsA total of 141 patients were enrolled. At diagnosis, median age was 69 years, 63.1% were female, 88.7% had metastatic disease, 94.3% had adenocarcinoma histology, 76.6% had ECOG 0/1, 70.9% had common EGFR mutations and 29.1% had only rare mutations. In first line, 73.8% of patients received first/second-generation EGFR–tyrosine kinase inhibitors (1G/2G EGFR-TKIs), while 21.9% received other systemic treatments. Among 61 patients progressing on and discontinuing a first 1G/2G EGFR-TKI, 45 (73.8%) received subsequent systemic treatment while 16 (26.2%) did not; 20 (32.8%) received osimertinib. Among 65 patients progressing on a first 1G/2G EGFR-TKI, 47 (72.3%) were tested for T790M, of whom 25 (53.2%) were positive.ConclusionThese real-world data from Belgium show that a substantial fraction of patients with EGFRm NSCLC do not receive 1G/2G EGFR-TKIs in first line and do not receive subsequent systemic treatment after progression on 1G/2G EGFR-TKIs. Only a third receive osimertinib upon progression on 1G/2G EGFR-TKIs. These observations should be considered in first-line treatment decisions.Trial RegistrationClinicalTrials.gov: NCT03761901—December 3, 2018

Extracellular Vesicle miR-200c Enhances Gefitinib Sensitivity in Heterogeneous EGFR-Mutant NSCLC.

Intratumoral heterogeneity in epidermal growth factor receptor (EGFR)-mutant mutant non-small-cell lung cancer (NSCLC) explains the mixed responses to EGFR-tyrosine kinase inhibitors (TKIs). However, some studies showed tumors with low abundances of EGFR mutation still respond to EGFR-TKI, and the mechanism remained undetermined. Extracellular vesicles (EVs) can transmit antiapoptotic signals between drug-resistant and drug-sensitive cells. Herein, we profiled EVs from EGFR-mutant cells to identify a novel mechanism explaining why heterogenous EGFR-mutant NSCLC patients still respond to EGFR-TKIs. We first demonstrated that the EVs from EGFR-mutant changes the wild-type cells’ sensitivity to gefitinib by adding EV directly or coculturing EGFR wild-type (CL1-5) cells and EGFR-mutant (PC9) cells. In animal studies, only the combined treatment of PC9 EV and gefitinib delayed the tumor growth of CL1-5 cells. MicroRNA analysis comparing EV miRNAs from PC9 cells to those from CL1-5 cells showed that mir200 family members are most abundant in PC9 EVs. Furthermore, mir200a and mir200c were found upregulated in plasma EVs from good responders to EGFR-TKIs. Finally, the transfection of CL1-5 cells with miR200c inactivates downstream signaling pathways of EGFR, the EMT pathway, and enhances gefitinib sensitivity. Overall, our results suggest that in heterogeneous EGFR-mutant NSCLC, tumor cells transmit EV miRNAs that may affect sensitivity to EGFR-TKIs and provide potential prognostic biomarkers for EGFR-mutant NSCLC.

Improvement of EGFR Testing over the Last Decade and Impact of Delaying TKI Initiation.

Background: Epidermal growth factor receptor (EGFR) is the most common oncogenic mutation in lung adenocarcinoma and tyrosine kinase inhibitors (TKIs) have been considered standard treatment for more than a decade. However, time to initiation of TKIs (TTIT) from diagnosis is often delayed and represents a challenge for clinicians. We aimed to assess the impact of TTIT on clinical outcomes and complications. Method: TTIT was defined as the time between confirmed advanced diagnosis and the initiation of a TKI. Complications during this pre-TKI period were retrospectively collected from all patients with EGFR-mutant non small cell lung cancer (NSCLC) in our institution. Results: 102 patients were diagnosed with EGFR mutated NSCLC between 2006 and 2019. The median PFS and OS were 12.9 and 22.5 months, respectively. TTIT was 5.7 months (95% CI 3.4–8) with a significant decrease in the latter years of this cohort. During the pre-TKI period, 23 patients received chemotherapy as first line treatment, of which 5 developed severe adverse events and 3 were not fit to receive TKI thereafter. Additionally, 29 patients had rapid clinical deterioration before initiation of first line TKI and 16 had to be hospitalized. Among the patients presenting a performance status deterioration, their prognosis was markedly affected compared to the remainder of the cohort (p = 0.01). Conclusion: Our real-world evidence study supports the concept that a delay to treat EGFR mutant NSCLC with TKIs is associated with adverse events, patient progression, hospitalization, and decreased overall survival. Rapid molecular diagnosis, including access to ctDNA technology may circumvent these deleterious delays.

Detection of Tumor-Associated Membrane Receptors on Extracellular Vesicles from Non-Small Cell Lung Cancer Patients via Immuno-PCR.

Simple SummaryLung cancer is often detected at late stages when metastases are present and the genomic make-ups of the tumors are heterogeneous. Analyses of genomic alterations in non-small-cell lung cancer (NSCLC) have revealed mutated tumor-associated membrane receptors and fusion proteins, which can be targeted via tyrosine kinase inhibitors (TKIs). TKIs initially often have a good effect, but a fraction of the tumor lesions may develop resistance through additional mutations in the targeted kinases or by increased expression/function of other membrane receptors. Detection of TKI-bypassing mechanisms is difficult in tissue biopsies as these analyze only a subpart of tumors or lesions. Liquid biopsies based on tumor-secreted small extracellular vesicles (sEVs) into body fluids can assess tumor heterogeneity. We present an immuno-PCR method for the detection of the epidermal growth factor receptor (EGFR), the human epidermal growth factor receptor 2 (HER2), and the insulin-like growth factor 1 receptor (IGF-1R) on sEVs. Initial investigations of sEVs from EGFR-mutant NSCLC tumor cells or pleural effusion (PE) fluid from patients with NSCLC or benign diseases showed different protein profiles for individual sEV samples. Further development of the immuno-PCR could complement DNA/mRNA-based assays detecting kinase mutations to allow longitudinal treatment monitoring of diverse TKI-bypassing mechanisms.Precision cancer medicine for non-small-cell lung cancer (NSCLC) has increased patient survival. Nevertheless, targeted agents towards tumor-associated membrane receptors only result in partial remission for a limited time, calling for approaches which allow longitudinal treatment monitoring. Rebiopsy of tumors in the lung is challenging, and metastatic lesions may have heterogeneous signaling. One way ahead is to use liquid biopsies such as circulating tumor DNA or small extracellular vesicles (sEVs) secreted by the tumor into blood or other body fluids. Herein, an immuno-PCR-based detection of the tumor-associated membrane receptors EGFR, HER2, and IGF-1R on CD9-positive sEVs from NSCLC cells and pleural effusion fluid (PE) of NSCLC patients is developed utilizing DNA conjugates of antibody mimetics and affibodies, as detection agents. Results on sEVs purified from culture media of NSCLC cells treated with anti-EGFR siRNA, showed that the reduction of EGFR expression can be detected via immuno-PCR. Protein profiling of sEVs from NSCLC patient PE samples revealed the capacity to monitor EGFR, HER2, and IGF-1R with the immuno-PCR method. We detected a significantly higher EGFR level in sEVs derived from a PE sample of a patient with an EGFR-driven NSCLC adenocarcinoma than in sEVs from PE samples of non-EGFR driven adenocarcinoma patients or in samples from patients with benign lung disease. In summary, we have developed a diagnostic method for sEVs in liquid biopsies of cancer patients which may be used for longitudinal treatment monitoring to detect emerging bypassing resistance mechanisms in a noninvasive way.

Treatment outcome and pattern of recurrence of sinonasal squamous cell carcinoma with EGFR-mutation and human papillomavirus

The objective of our study was to clarify the clinical features of EGFR-mutated sinonasal squamous cell carcinoma (SNSCC) and human papilloma virus (HPV)-related SNSCC.Patients with SNSCC treated from April 2008 to June 2019 at our institution were retrospectively reviewed. We examined EGFR mutation and HPV status for all patients. Main outcomes were overall survival, recurrence, and outcome of each treatment modality.A total of 85 patients with SNSCC were enrolled in this study. EGFR mutations and HPV DNA were detected in 24 (28%) and 7 (8%) patients, respectively. Patients with EGFR-mutated SNSCC showed a worse overall survival (OS) than those with EGFR wild-type in the multivariate analysis (p = 0.037). No death was observed in HPV-positive SNSCC. The cumulative incidence of local recurrence was significantly higher in EGFR mutant than EGFR wild-type tumors (p = 0.03). In patients with EGFR mutations, treatment with induction chemotherapy significantly improved OS (p = 0.01).EGFR-mutated SNSCC have a high-risk feature for recurrence and requires intensive attention for treatment and observation. A new treatment approach, such as EGFR tyrosine kinase inhibitors, may be needed.

Abstract PS10-06: Comparative analysis of anti-proliferative effects and gene profiling of lapatinib, neratinib, and tucatinib

Abstract Introduction: Human epidermal growth factor 2 (HER2/ERBB2) is frequently amplified or mutated across various cancer types. The tyrosine kinase inhibitors (TKIs) lapatinib, neratinib, and tucatinib are FDA-approved for the treatment of HER2-positive breast cancer. All three TKIs bind and inhibit the kinase domain of HER2 but differ both in the mechanism of binding and in specificity for other HER family members. Direct comparisons to differentiate the pre-clinical efficacy of the three TKIs have been limited to small-scale studies and novel biomarkers of response to further define appropriate patient populations are required. Methods: In this study, the anti-proliferative effects of the three TKIs were compared using a 115-cancer cell line panel, including 12 breast cancer cell lines and 22 cell lines harbouring point mutations or amplifications of EGFR, HER2, or HER3. Hierarchical clustering analysis was carried out to compare the IC50 “fingerprint” of the three TKIs to 168 other anti-cancer agents. Novel markers of TKI sensitivity and resistance were identified through cross-analysis of each drug response profile with mutation, copy number variation, and gene expression data. Results: All three TKIs were effective against HER2-positive breast cancer models; neratinib showed the most potent activity, followed by tucatinib and lapatinib respectively (Table 1). Neratinib displayed the greatest anti-proliferative activity in HER2-mutant and EGFR-mutant cell lines. Clustering analysis revealed that the anti-proliferative profile of tucatinib was most similar to trastuzumab, while neratinib and lapatinib were most like other HER family inhibitors. Mutation and gene expression analysis identified potential markers of response for each TKI. High expression of four genes (HER2, VTCN1, CDK12, and RAC1) correlated with response to all three TKIs. DNA damage repair genes were significantly associated with resistance to the HER2-targeted TKIs. BRCA2 mutation was correlated with neratinib and tucatinib response, and high gene expression of ATM, BRCA2, and BRCA1 were all associated with neratinib resistance. Conclusions: Neratinib was the most effective HER2-targeted TKI against HER2-amplified, -mutant, and EGFR-mutant cell lines. This analysis revealed possible mechanisms that may be exploited using combinatorial strategies involving CDK inhibitors, immunotherapies, and targeting DNA repair pathways. Table: IC50 values for neratinib, lapatinib, and tucatinib in the HER2+ breast cancer cell linesIC50 values (nM)Cell linesNeratinibLapatinibTucatinibAU-56520294125BT-4745926229HCC195413814262122MDA-MB-453306228445928SKBR3715222 Citation Format: Neil T Conlon, Jeffrey J Kooijman, Suzanne JC van Gerwen, Winfried R Mulder, Guido JR Zaman, Irmina Diala, Lisa D Eli, Alshad S Lalani, John Crown, Denis Collins. Comparative analysis of anti-proliferative effects and gene profiling of lapatinib, neratinib, and tucatinib [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-06.

Akt kinase LANCL2 functions as a key driver in EGFR-mutant lung adenocarcinoma tumorigenesis

Epidermal growth factor receptor (EGFR) is a key oncogene in lung adenocarcinoma (LUAD). Resistance to EGFR tyrosine kinase inhibitors is a major obstacle for EGFR-mutant LUAD patients. Our gene chip array, quantitative polymerase chain reaction validation, and shRNA-based high-content screening identified the Akt kinase lanthionine synthetase C-like protein 2 (LANCL2) as a pro-proliferative gene in the EGFR-mutant LUAD cell line PC9. Therefore, we investigated whether LANCL2 plays a role in promoting cell proliferation and drug resistance in EGFR-mutant LUAD. In silico clinical correlation analysis using the Cancer Genome Atlas Lung Adenocarcinoma dataset revealed a positive correlation between LANCL2 and EGFR expression and an inverse relationship between LANCL2 gain-of-function and survival in LUAD patients. The EGFR-mutant LUAD cell lines PC9 and HCC827 displayed higher LANCL2 expression than the non-EGFR-mutant cell line A549. In addition, LANCL2 was downregulated following gefitinib+pemetrexed combination therapy in PC9 cells. LANCL2 knockdown reduced proliferation and enhanced apoptosis in PC9, HCC827, and A549 cells in vitro and suppressed murine PC9 xenograft tumor growth in vivo. Notably, LANCL2 overexpression rescued these effects and promoted gefitinib + pemetrexed resistance in PC9 and HCC827 cells. Pathway analysis and co-immunoprecipitation followed by mass spectrometry of differentially-expressed genes in LANCL2 knockdown cells revealed enrichment of several cancer signaling pathways. In addition, Filamin A and glutathione S-transferase Mu 3 were identified as two novel protein interactors of LANCL2. In conclusion, LANCL2 promotes tumorigenic proliferation, suppresses apoptosis, and promotes gefitinib+pemetrexed resistance in EGFR-mutant LUAD cells. Based on the positive association between LANCL2, EGFR, and downstream Akt signaling, LANCL2 may be a promising new therapeutic target for EGFR-mutant LUAD.

Comparative analysis of drug response and gene profiling of HER2-targeted tyrosine kinase inhibitors

BackgroundHuman epidermal growth factor 2 (HER2/ERBB2) is frequently amplified/mutated in cancer. The tyrosine kinase inhibitors (TKIs) lapatinib, neratinib, and tucatinib are FDA-approved for the treatment of HER2-positive breast cancer. Direct comparisons of the preclinical efficacy of the TKIs have been limited to small-scale studies. Novel biomarkers are required to define beneficial patient populations.MethodsIn this study, the anti-proliferative effects of the three TKIs were directly compared using a 115 cancer cell line panel. Novel TKI response/resistance markers were identified through cross-analysis of drug response profiles with mutation, gene copy number and expression data.ResultsAll three TKIs were effective against HER2-amplified breast cancer models; neratinib showing the most potent activity, followed by tucatinib then lapatinib. Neratinib displayed the greatest activity in HER2-mutant and EGFR-mutant cells. High expression of HER2, VTCN1, CDK12, and RAC1 correlated with response to all three TKIs. DNA damage repair genes were associated with TKI resistance. BRCA2 mutations were correlated with neratinib and tucatinib response, and high expression of ATM, BRCA2, and BRCA1 were associated with neratinib resistance.ConclusionsNeratinib was the most effective HER2-targeted TKI against HER2-amplified, -mutant, and EGFR-mutant cell lines. This analysis revealed novel resistance mechanisms that may be exploited using combinatorial strategies.