Epidermal Growth Factor Tyrosine Kinase Research Articles

Protein kinase A-mediated phosphorylation of naked cuticle homolog 2 stimulates cell-surface delivery of transforming growth factor-α for epidermal growth factor receptor transactivation.

The classic mode of G protein‐coupled receptor (GPCR)‐mediated transactivation of the receptor tyrosine kinase epidermal growth factor receptor (EGFR) transactivation occurs via matrix metalloprotease (MMP)‐mediated cleavage of plasma membrane‐anchored EGFR ligands. Herein, we show that the Gαs‐activating GPCR ligands vasoactive intestinal peptide (VIP) and prostaglandin E2 (PGE2) transactivate EGFR through increased cell‐surface delivery of the EGFR ligand transforming growth factor‐α (TGFα) in polarizing madin‐darby canine kidney (MDCK) and Caco‐2 cells. This is achieved by PKA‐mediated phosphorylation of naked cuticle homolog 2 (NKD2), previously shown to bind TGFα and direct delivery of TGFα‐containing vesicles to the basolateral surface of polarized epithelial cells. VIP and PGE2 rapidly activate protein kinase A (PKA) that then phosphorylates NKD2 at Ser‐223, a process that is facilitated by the molecular scaffold A‐kinase anchoring protein 12 (AKAP12). This phosphorylation stabilized NKD2, ensuring efficient cell‐surface delivery of TGFα and increased EGFR activation. Thus, GPCR‐triggered, PKA/AKAP12/NKD2‐regulated targeting of TGFα to the cell surface represents a new mode of EGFR transactivation that occurs proximal to ligand cleavage by MMPs.

Liver X receptor agonist T0901317 inhibits the migration and invasion of non-small-cell lung cancer cells in vivo and in vitro.

Liver X receptors are recognized as important regulators of cholesterol, fatty acid metabolism, inflammatory responses, and glucose homeostasis. The antineoplastic properties of synthetic liver X receptor (LXR) agonists (T0901317 and GW3965) have been reported in human carcinomas. Epidermal growth factor tyrosine kinase inhibitor (EGFR-TKI) is a first-line treatment for non-small-cell lung cancer patients with EGFR mutations. We used scratch and transwell assays to analyze cell migration and invasion. We evaluated tumor migration and invasion in vitro using a fluorescent orthotopic lung cancer model. An MMP9 (mouse) enzyme-linked immunosorbent assay kit was used to measure serum MMP9 concentrations. Protein expression was identified by western blot assays. In this study, we determined the effects of T0901317 and/or an EGFR-TKI on the lung cancer cell lines A549 and HCC827-8-1 in vitro and in vivo. We confirmed that the combination of the LXR agonist T0901317 and gefitinib can inhibit the migration and invasion of lung cancer both in vivo and in vitro, and this effect was possibly achieved by the inhibition of the ERK/MAPK signaling pathway. Our study showed that the combination of the LXR agonist T0901317 and gefitinib can inhibit the migration and invasion of lung cancer both in vivo and in vitro.

Biological Evaluation and Molecular Dynamics Simulation of Chalcone Derivatives as Epidermal Growth Factor-Tyrosine Kinase Inhibitors.

Targeted cancer therapy has become a high potential cancer treatment. Epidermal growth factor receptor (EGFR), which plays an important role in cell signaling, enhanced cell survival and proliferation, has been suggested as molecular target for the development of novel cancer therapeutics. In this study, a series of chalcone derivatives was screened by in vitro cytotoxicity against the wild type (A431 and A549) and mutant EGFR (H1975 and H1650) cancer cell lines, and, subsequently, tested for EGFR-tyrosine kinase (TK) inhibition. From the experimental screening, all chalcones seemed to be more active against the A431 than the A549 cell line, with chalcones 1c, 2a, 3e, 4e, and 4t showing a more than 50% inhibitory activity against the EGFR-TK activity and a high cytotoxicity with IC50 values of < 10 µM against A431 cells. Moreover, these five chalcones showed more potent on H1975 (T790M/L858R mutation) than H1650 (exon 19 deletion E746-A750) cell lines. Only three chalcones (1c, 2a and 3e) had an inhibitory activity against EGFR-TK with a relative inhibition percentage that was close to the approved drug, erlotinib. Molecular dynamics studies on their complexes with EGFR-TK domain in aqueous solution affirmed that they were well-occupied within the ATP binding site and strongly interacted with seven hydrophobic residues, including the important hinge region residue M793. From the above information, as well as ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties, all three chalcones could serve as lead compounds for the development of EGFR-TK inhibitors.

The role of histone lysine demethylases in cancer cells' resistance to tyrosine kinase inhibitors.

Current cancer therapies are often associated with treatment failure and reduced patients’ survival due to drug resistance. There are various mechanisms involved in the acquisition of cancer drug resistance, including the selection of advantageous mutations, overexpression of transporter proteins and epigenetic alterations. In this context, epigenetic alterations refer to chromatin-mediated regulation of gene expression that results in heritable changes in the cellular phenotype. There is an ever-growing body of evidence suggesting that epigenetic mechanisms play an important role in bringing about drug resistance in cancer cells. While the relationship between chemotherapy and epigenetics has been widely discussed, emerging evidence indicates that specific epigenetic effectors are also crucial for the development of resistance to tyrosine kinase inhibitors (TKIs). One particular gene that encodes the histone lysine demethylase KDM5A is overexpressed in several cancers. In breast cancer tissues, cells with KDM5A gene amplification were found to be more resistant to erlotinib, an inhibitor of the tyrosine kinase epidermal growth factor receptor (EGFR), when compared to cells without the same amplification. KDM5A was also shown to mediate resistance to a second EGFR inhibitor called gefitinib, in EGFR-mutant lung cancer cell lines. This evidence indicates that KDM5A could activate alternative survival pathways involved in overcoming EGFR inhibition. In line with these results, another histone demethylase (i.e., KDM1A) promotes liver cancer cells’ resistance to the TKI sorafenib. Current evidence provides a suitable rationale to consider the use of specific KDMs inhibitors to sensitize cells to tyrosine kinase targeted therapies and thus, presents an opportunity to prevent the further development of drug resistance. This review discusses the involvement of histone lysine demethylases in the development of resistance to TKI and highlights the importance to develop new cancer treatment regimens to counteract this phenomenon.

MUCOADHESIVE CHITOSAN MICROSPHERES OF GEFITINIB

Objective: Gefitinib, Epidermal Growth Factor-Tyrosine Kinase Inhibitor (EGFR-TKI); has promisingly shown activity against Non-Small-Scale Lung Cancer. Currently, the formulations of this drug available are in Tablets, Capsules and liposomal suspensions taken by the oral route. These have certain disadvantages in gastrointestinal disorders like irritation of GI mucosal layer, bleeding, non-patient compliance and low bioavailability due to low aqueous solubility and thus low bioavailability. The purpose of this study was to formulate and evaluate Chitosan-based Microparticles of Gefitinib for maintaining the therapeutic index and limits its side effects.Methods: Chitosan microspheres cross-linked with glutaraldehyde were prepared by solvent evaporation technique which is then analyzed for its particle size, encapsulation efficiency, swelling index.Results: The release rate of the drug can be increased by using chitosan-based carrier system which will enhance its bioavailability. By this work, the anticancer activity of Gefitinib in non-small-scale lung cancer will be successfully determined.Conclusion: It has been concluded that microspheres can be prepared by solvent evaporation technique by varying the concentration of chitosan and tween-20. Chitosan used in this work is of 85 % degree of deacetylation, 25 % solution of Gluteraldehyde suitable for the formulation of these microspheres. Optimized temperature was selected as 65 °C, and the rotation speed was taken as 1200 rpm. Finally, the objectives planned for this research work was performed and evaluated and shown promising results as the dosing frequency is reduced and maximize for 3 d rather than once in a day as per the current formulation available in the market now with a low dosage regimen of 100 mg of dosage strength, administer by pulmonary route. Microparticulate drug delivery system from microspheres is able to deliver the drug in a sustained release manner for the long period of time successfully.

Abstract 2414: Interrogating cellular metabolism reveals mTORC2 as a new biomarker to stratify epidermal growth factor receptor-mutant non-small cell lung cancer

Abstract Most non-small cell lung cancer (NSCLC) patients with epidermal growth factor (EGFR) mutations initially respond to EGFR tyrosine-kinase inhibitors (TKIs), but these inhibitors are only effective for approximately one year, thus limiting the benefits to patients' survival. Stratification of patients with EGFR-mutant NSCLC would help physicians personalize and optimize patient treatment plans. To this end, we hypothesized that factors residing in the tumor microenvironment play a pivotal role in the evolutionary dynamics of therapeutic response to anti-EGFR therapies. We used the Operetta® High Content Imaging System to track cell dynamics over time under different microenvironmental stresses, and we found that the growth of TKI-resistant cells is more sensitive to glucose starvation than TKI-sensitive cells. To further interrogate cellular metabolism in TKI-sensitive and resistant cells, we utilized both seahorse metabolic assays and fluorescence lifetime imaging microscopy to monitor the changes in glycolysis and oxidative phosphorylation of living cells. We found TKI-resistant cells have higher glycolysis and lower oxidative phosphorylation rates compared to TKI-sensitive cells. Such metabolic reprogramming rendered TKI-resistant cells with lower metabolic plasticity to cope with metabolic stress. Using both genetic and pharmacologic approaches, we then demonstrated that mTORC2 activation contributes to the different metabolic phenotypes between TKI-sensitive and resistant cells. Furthermore, gene set enrichment analysis showed that the oxidative phosphorylation gene set is significantly enriched in patients with low mTORC2 activation, and the glycolysis gene set is upregulated in patients with high mTORC2 activation, which is correlated with shorter progression-free and overall survival time in patients. Overall, these data suggest that TKI-resistant cells use and require distinct metabolic programs that can be employed to stratify EGFR-mutant NSCLC patients for treatment with EGFR-TKIs. Citation Format: Chun-Te Chiang, Nolan Ung, Alexandra N. Demetriou, Chi-Li Chiu, Niha Choudhury, Cosimo Arnesano, Scott E. Fraser, David B. Agus, Naim Matasci, Dan L. Ruderman, Shannon M. Mumenthaler. Interrogating cellular metabolism reveals mTORC2 as a new biomarker to stratify epidermal growth factor receptor-mutant non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2414.

Chemotherapy with or without pemetrexed as second-line regimens for advanced non-small-cell lung cancer patients who have progressed after first-line EGFR TKIs: a systematic review and meta-analysis.

PurposeThe development of acquired resistance to the first-line epidermal growth factor-tyrosine kinase inhibitor (EGFR-TKI) treatment in non-small-cell lung cancer (NSCLC) is inevitable, and most of these patients needed second-line chemotherapy. Furthermore, the optimum chemotherapeutic regimen is unclear. The aim of this meta-analysis was to evaluate the chemotherapeutic regimens “with-pemetrexed” versus “non-pemetrexed” in advanced NSCLC patients who had progressed after first-line EGFR-TKIs.Materials and methodsWe searched PubMed, Embase, Cochrane Library, and the Web of science for relevant clinical trials. Outcomes analyzed were response rate (RR), disease control rate (DCR), 1-year survival rate (1-year SR), progression-free survival (PFS), and overall survival (OS).ResultsOne randomized controlled trial (RCT) and three retrospective studies were included in this meta-analysis, covering a total of 354 patients. The results showed that there was no significant difference between with-pemetrexed arm and non-pemetrexed arm in RR (OR 1.43, 95% CI 0.85–2.41, P=0.18), DCR (OR 1.5, 95% CI 0.94–2.39, P=0.09), and 1-year SR (OR 1.47, 95% CI 0.79–2.74, P=0.22). But the with-pemetrexed chemotherapeutic regimens significantly improved the PFS (HR 0.61, 95% CI 0.46–0.81, P=0.0005) and OS (HR 0.62, 95% CI 0.42–0.90, P=0.01).ConclusionThe second-line with-pemetrexed chemotherapeutic regimens provided significantly longer PFS and OS than non-pemetrexed chemotherapeutic regimens. These findings indicate that the with-pemetrexed chemotherapeutic regimen may be an optimal second-line chemotherapeutic regimen for patients with advanced NSCLC following EGFR-TKI failure.

PCN188 - Emergent Therapies And Egfr Mutation Testing In Non-Small Cell Lung Cancer: Real-World Practices

This study aims to characterize the utilization of epidermal growth factor receptor (EGFR) mutation testing and tyrosine kinase inhibitor (TKI) prescribing practices in a population of non-small cell lung cancer (NSCLC) patients at a large hospital in Central Texas. A cohort of newly diagnosed NSCLC patients was identified from the hospital’s cancer registry from 2014 through 2015. The diagnosis date served as the index date for each patient with the follow-up period consisting of one year after the index date. Baseline patient and tumor data were obtained from the cancer registry. During the follow-up period, the utilization of EGFR mutation testing and prescribing of TKIs were obtained from the electronic medical record. Descriptive statistics were performed. There were 617 patients with newly diagnosed NSCLC from 2014 through 2015 and 242 had Stage IV disease. Of those with Stage IV disease, 58% had adenocarcinoma with an additional 19% with unspecified histology. Out of all EGFR mutation testing completed within 40 days of diagnosis, 55% were conducted in non-Stage IV disease. Of patients with Stage IV adenocarcinomas, 68% were tested for EGFR mutations within 40 days of diagnosis. Of that group, 25 patients were then positive for EGFR and 23 were placed on TKI therapy (90% erlotinib and 10% afatinib). This study provides preliminary data in the testing and treatment of EGFR positive NSCLC. Due to limitations in electronic medical record data, the rate of testing may be underestimated. Despite this limitation, these results indicate a gap between actual testing patterns and guideline recommended testing algorithms.

Cabazitaxel Plus Lapatinib as Therapy for HER2+ Metastatic Breast Cancer With Intracranial Metastases: Results of a Dose-finding Study

BackgroundLapatinib is an oral small molecule tyrosine kinase epidermal growth factor receptor-1/HER2 inhibitor that crosses the blood–brain barrier and is active against central nervous system (CNS) metastases. Cabazitaxel is a taxoid that is effective against taxane-resistant metastatic breast cancer (MBC) and has distinguished itself by its ability to cross the blood–brain barrier. The present phase II study (ClinicalTrials.gov identifier, NCT01934894) evaluated the combination of these agents to treat HER2+ MBC patients with CNS metastases. Materials and MethodsPatients with HER2+ MBC and ≥ 1 untreated or progressive, measurable CNS metastasis were eligible. Using a 3+3 dose escalation design, patients were treated with escalating doses of intravenous cabazitaxel every 21 days and oral lapatinib daily in 21-day treatment cycles. Intracranial disease restaging was performed every 2 cycles for the first 8 cycles and then every 3 cycles until progression or unacceptable toxicity. ResultsEleven patients were treated at 2 dose levels. Six patients were treated at dose level 1 (intravenous cabazitaxel 20 mg/m2 plus oral lapatinib 1000 mg daily), and five were treated at dose level 2 (intravenous cabazitaxel 25 mg/m2 plus oral lapatinib 1000 mg daily). The most common treatment-related adverse events were myelosuppression, diarrhea, fatigue, and skin toxicity. A total of 5 dose-limiting toxicity events occurred. No intra- or extracranial objective responses were observed. ConclusionThe combination of cabazitaxel plus lapatinib was not feasible because of toxicity and because no objective CNS activity was seen in the 5 evaluable patients. The role of cabazitaxel to treat breast cancer patients with CNS metastases remains undefined.

Role of GPCR (mu-opioid)-receptor tyrosine kinase (epidermal growth factor) crosstalk in opioid-induced hyperalgesic priming (type II).

Repeated stimulation of mu-opioid receptors (MORs), by an MOR-selective agonist DAMGO induces type II priming, a form of nociceptor neuroplasticity, which has 2 components: opioid-induced hyperalgesia (OIH) and prolongation of prostaglandin-E2 (PGE2)-induced hyperalgesia. We report that intrathecal antisense knockdown of the MOR in nociceptors, prevented the induction of both components of type II priming. Type II priming was also eliminated by SSP-saporin, which destroys the peptidergic class of nociceptors. Because the epidermal growth factor receptor (EGFR) participates in MOR signaling, we tested its role in type II priming. The EGFR inhibitor, tyrphostin AG 1478, prevented the induction of prolonged PGE2-induced hyperalgesia, but not OIH, when tested out to 30 days after DAMGO. However, even when repeatedly injected, an EGFR agonist did not induce hyperalgesia or priming. A phosphopeptide, which blocks the interaction of Src, focal adhesion kinase (FAK), and EGFR, also prevented DAMGO-induced prolongation of PGE2 hyperalgesia, but only partially attenuated the induction of OIH. Inhibitors of Src and mitogen-activated protein kinase (MAPK) also only attenuated OIH. Inhibitors of matrix metalloproteinase, which cleaves EGF from membrane protein, markedly attenuated the expression, but did not prevent the induction, of prolongation of PGE2 hyperalgesia. Thus, although the induction of prolongation of PGE2-induced hyperalgesia at the peripheral terminal of peptidergic nociceptor is dependent on Src, FAK, EGFR, and MAPK signaling, Src, FAK, and MAPK signaling is only partially involved in the induction of OIH.

Identification of Clinically Approved Drugs Indacaterol and Canagliflozin for Repurposing to Treat Epidermal Growth Factor Tyrosine Kinase Inhibitor-Resistant Lung Cancer.

In advanced lung cancer, epidermal growth factor tyrosine kinase inhibitors (EGFR TKIs) have extraordinary clinical efficacy. However, their usefulness is severely compromised by drug resistance mediated by various mechanisms, the most important of which is the secondary EGFR T790M mutation. The mutation blocks the binding of EGFR TKIs to the receptor kinase, thereby abolishing the therapeutic efficacy. In this study, we used our free and open-source protein-ligand docking software idock to screen worldwide approved small-molecule drugs against EGFR T790M. The computationally selected drug candidates were evaluated in vitro in resistant non-small cell lung cancer (NSCLC) cell lines. The specificity of the drugs toward the mutant EGFR was demonstrated by cell-free kinase inhibition assay. The inhibition of EGFR kinase activity and its downstream signaling pathways in NSCLC cells was shown by immunoblot analysis. The positive hints were revealed to be indacaterol, canagliflozin, and cis-flupenthixol, all of which were shown to induce apoptosis in NSCLC cells harboring the EGFR T790M mutation. Moreover, the combination of indacaterol with gefitinib was also found to produce synergistic anticancer effect in NSCLC cells bearing EGFR T790M. The observed synergistic effect was likely contributed by the enhanced inhibition of EGFR and its downstream signaling molecules.

Histological transformation after acquired resistance to epidermal growth factor tyrosine kinase inhibitors.

Non-small-cell lung cancer patients with sensitive epidermal growth factor receptor mutations generally respond well to tyrosine kinase inhibitors (TKIs). However, acquired resistance will eventually develop place after 8-16months. Several mechanisms contribute to the resistance including T790M mutation, c-Met amplification, epithelial mesenchymal transformation and PIK3CA mutation; however, histological transformation is a rare mechanism. The patterns and mechanisms underlying histological transformation need to be explored. We searched PubMed, EMBASE and search engines Google Scholar, Medical Matrix for literature related to histological transformation. Case reports, cases series, and clinical and basic medical research articles were reviewed. Sixty-one articles were included in this review. Cases of transformation to small-cell lung cancer, squamous cell carcinoma, large-cell neuroendocrine carcinoma and sarcoma after TKI resistance have all been reported. As the clinical course differed dramatically between cases, a new treatment scheme needs to be recruited. The mechanisms underlying histological transformation have not been fully elucidated and probably relate to cancer stem cells, driver genetic alterations under selective pressure or the heterogeneity of the tumor. When TKI resistance develops, we recommend that patients undergo a second biopsy to determine the reason, guide the next treatment and predict the prognosis.

Metabolic profiling of triple-negative breast cancer cells reveals metabolic vulnerabilities

BackgroundAmong breast cancers, the triple-negative breast cancer (TNBC) subtype has the worst prognosis with no approved targeted therapies and only standard chemotherapy as the backbone of systemic therapy. Unique metabolic changes in cancer progression provide innovative therapeutic opportunities. The receptor tyrosine kinases (RTKs) epidermal growth factor receptor (EGFR), and MET receptor are highly expressed in TNBC, making both promising therapeutic targets. RTK signaling profoundly alters cellular metabolism by increasing glucose consumption and subsequently diverting glucose carbon sources into metabolic pathways necessary to support the tumorigenesis. Therefore, detailed metabolic profiles of TNBC subtypes and their response to tyrosine kinase inhibitors may identify therapeutic sensitivities.MethodsWe quantified the metabolic profiles of TNBC cell lines representing multiple TNBC subtypes using gas chromatography mass spectrometry. In addition, we subjected MDA-MB-231, MDA-MB-468, Hs578T, and HCC70 cell lines to metabolic flux analysis of basal and maximal glycolytic and mitochondrial oxidative rates. Metabolic pool size and flux measurements were performed in the presence and absence of the MET inhibitor, INC280/capmatinib, and the EGFR inhibitor, erlotinib. Further, the sensitivities of these cells to modulators of core metabolic pathways were determined. In addition, we annotated a rate-limiting metabolic enzymes library and performed a siRNA screen in combination with MET or EGFR inhibitors to validate synergistic effects.ResultsTNBC cell line models displayed significant metabolic heterogeneity with respect to basal and maximal metabolic rates and responses to RTK and metabolic pathway inhibitors. Comprehensive systems biology analysis of metabolic perturbations, combined siRNA and tyrosine kinase inhibitor screens identified a core set of TCA cycle and fatty acid pathways whose perturbation sensitizes TNBC cells to small molecule targeting of receptor tyrosine kinases.ConclusionsSimilar to the genomic heterogeneity observed in TNBC, our results reveal metabolic heterogeneity among TNBC subtypes and demonstrate that understanding metabolic profiles and drug responses may prove valuable in targeting TNBC subtypes and identifying therapeutic susceptibilities in TNBC patients. Perturbation of metabolic pathways sensitizes TNBC to inhibition of receptor tyrosine kinases. Such metabolic vulnerabilities offer promise for effective therapeutic targeting for TNBC patients.

Beyond disease-progression: Clinical outcomes after EGFR-TKIs in a cohort of EGFR mutated NSCLC patients.

PurposeTreatment and clinical-outcomes were described in a sub-cohort of non-small-cell lung cancer (NSCLC) patients with disease-progression (PD) after epidermal growth factor tyrosine kinase inhibitors (EGFR-TKIs) treatment.Patients and methodsWe retrospectively analyzed a single-institutional EGFR mutation positive (EGFRmut+) NSCLC cohort for post-TKI-PD management, and assessed overall survival (OS) and post-progression survival (PPS). All de-novo (first lung-cancer occurrence) stage IIIA-IV patients, as well as de-novo stage IV subset was analyzed. Multi-state modeling (MSM) and a Cox PH regression model with propensity score weights adjusted for clinicopathological variables between: diagnosis and PD and PD to death.Results123 stage IIIA-IV patients were identified with 104 meeting RECIST-1.1-PD criteria. This RECIST-1.1-PD criteria subset included females (64.6%), Asians (39.4%), never/non-smokers (55.8%), and exon 19 deletion carriers (44.2%). Commonest treatment beyond initial-PD was continuing TKI alone (46/104), with another 21 patients continuing TKI plus additional systemic therapy. The median OS for patients who continued TKI treatment at initial-PD was 21.1 months versus 15.6 months for patients who discontinued TKI, p = 0.006. Via MSM analysis, continuing TKI at initial-PD followed by other systemic therapy was associated with an 83% reduced death risk, adjusted HR: 0.17 (95% CI: 0.07, 0.39). In the Cox PH model, ever-smokers with an exon 19 deletion had increased risk of death after PD (adjusted HR: 3.19, 95% CI: 1.54, 6.58), as did exon 21 mutation carriers, (adjusted HR: 2.10, 95% CI: 1.10, 4.00) and females (adjusted HR: 3.19, 95% CI: 1.54, 6.58).ConclusionSubsequent systemic therapy after continuing TKI at initial-PD reduced the risk of death. Additionally, our data suggest that positive smoking history increases death risk for some EGFR mutation types and females.

Abstract 1161: Dimethylaminoparthenolide (DMAPT), an oral nuclear factor kappa B inhibitor (NFκB), enhances radiation therapy and enhances epidermal growth factor tyrosine kinase inhibitor (EGFR TKI) activity

Abstract Introduction: NFκB can promote cancer and resistance to therapy as well as mediate tissue injury in response to radiation (XRT). We assessed DMAPT efficacy alone and in combination with XRT, and also with an EGFR TKI, and assessed whether it can mitigate XRT side effects. Methods: Six-week old male TRAMP (Transgenic Adenocarcinoma of the Mouse Prostate) mice received DMAPT (100 mg/kg) orally or vehicle control 3x/week until palpable tumors formed and lung metastases were analyzed histologically. In separate studies, 16 week old TRAMP mice were treated with 100 mg/kg DMAPT 3x over 1 week before 6 Gy whole-body XRT. Cancer and normal tissues were analyzed for apoptosis for up to 72 hours post-XRT. NCr nude mice were inoculated with H1975 (T790M mutation non small cell lung cancer, NSCLC) subcutaneously. When tumors reached 200 mm3, treatment (Rx) commenced: vehicle, DMAPT 100mg/kg/day, EGF TKI-AZD9291 25mg/kg/day, combination. Results: Long-term Rx with DMAPT extended the median time to palpable prostate tumor by 41.3 (p = 0.0013) days. Chronic DMAPT Rx reduced the number of metastatic lesions/mm2 in TRAMP lungs 20-fold (0.077 ± 0.12 SD) compared to a vehicle control (1.47 ± 1.28 SD) (p = 0.0004). XRT-induced apoptosis doubled in TRAMP prostates (with moderate to high grade PIN lesions) treated with DMAPT prior to 6 Gy XRT (101.3 % increase, p = 0.039). DMAPT induced the greatest radiosensitivity in TRAMP prostates with higher grade PIN (R2 = 0.79, p = 0.0001), while apoptosis frequency in tissues with lower grades of PIN was the same as vehicle control TRAMP mice (R2 = 0.024, p = 0.3). DMAPT also reduced XRT-induced apoptosis in healthy TRAMP spleen (32.9 % reduction, p = 0.003) and rectum (28.7 % reduction, p = 0.0001). In the H1975 experiment, DMAPT monotherapy did not differ from the vehicle controls. In the single agent AZD9291 group, 2 of the 8 mice had resistance emerge during Rx and adding DMAPT to AZD9291 reversed resistance in one of these. Rx was held at Day 220 in 3 remaining AZD9291 treated mice with no evidence of tumor and only 1 mouse was alive with no tumor at day 260. For mice receiving Rx with AZD9291 and DMAPT from D1, resistance emerged in 1 mouse, and at D140 all remaining mice with no evidence of tumor had Rx stopped, and 3 mice were still tumor free at D260. Two mice had regrowth, were retreated, and at D200 without evidence of tumors had Rx held, and one had no tumor at D260 at the end of the experiment. In total, 4 of 8 mice in the AZD9291 and DMAPT had no tumor off therapy at D260. Conclusion: Radiation and EGFR TKI resistance has been linked to NFκB activation. DMAPT slows down cancer progression and decreases metastatic lesions in a prostate cancer mouse model, protects normal tissue from radiation induced apoptosis, augments radiation induced apoptosis in prostate cancer and augments EGFR TKI efficacy in T790M mutant NSCLC. Citation Format: Katherine L. Morel, Pamela J. Sykes, Prafulla C. Gokhale, Gwo-Shu Mary Lee, Hong Tiv, Christopher J. Sweeney. Dimethylaminoparthenolide (DMAPT), an oral nuclear factor kappa B inhibitor (NFκB), enhances radiation therapy and enhances epidermal growth factor tyrosine kinase inhibitor (EGFR TKI) activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1161. doi:10.1158/1538-7445.AM2017-1161

Response to osimertinib following treatment with EGF816 in patients with T790M EGFR mutant NSLCLC.

e20673 Background: Third generation (3rd gen) epidermal growth factor (EGFR) tyrosine kinase inhibitors (TKIs) have been developed to treat EGFR T790M-mediated resistance to EGFR TKIs by inhibiting EGFR T790M, as well as EGFR L858R and EGFR exon 19 deletions. The mechanisms of resistance to third-generation EGFR TKIs are largely unknown and clinical cross-resistance among 3rd gen EGFR TKIs has not been routinely evaluated. Osimertinib is an FDA-approved irreversible 3rd gen EGFR TKI. In patients with EGFR T790M mutant NSCLC, the response rate (ORR) to osimertinib is 61%. EGF816 is a covalent, irreversible, 3rd gen EGFR TKI in clinical development. In early phase data of EGF816, the ORR was 47% and disease control rate was 87% in patients with EGFR T790M mutant NSCLC. To assess clinical cross-resistance between EGF816 and osimertinib, we evaluated the clinical outcomes of patients treated with osimertinib in patients previously treated with EGF816 during the phase I/II trial. Methods: Patients with metastatic EGFR mutant lung adenocarcinoma were identified who were previously treated with EGF816 and received osimertinib after progression of disease on EGF816 (NCT02108964). All patients had documented T790M mutation prior to treatment with EGF816. The best overall response to osimertinib was determined by RECIST 1.1 criteria. Duration of clinical benefit was defined as duration of osimertinib therapy. Results: Fourteen (3 men, 11 women, median age 58 [range 33-77]) patients met eligibility criteria at our centers. The ORR to subsequent osimertinib therapy was 14% (1 CR, 1 PR, 8 SD, 4 POD). Patients continued treatment with osimertinib for a median of 9 months (95% CI 3.8-10.1, [median follow up 11 months, range 1-13 months]). 5 patients are still on osimertinib to date (one patient each 3+, 6+, 8+, 11+, and 12+ months). Conclusions: This series suggests a potentially meaningful clinical benefit for patients with sequential therapy with two different third-generation EGFR inhibitors, emphasizing the importance of understanding resistance mechanisms (genetic alteration of target, bypass signaling, pharmacology, etc.) and raising the possibility of the need for multiple third generation EGFR TKIs in clinical practice.

Recent Advances and Prospect of Advanced Non-small Cell Lung Cancer Targeted Therapy: Focus on Small Molecular Tyrosine Kinase Inhibitors

目前晚期非小细胞肺癌的治疗已经迈入靶向时代并且发展迅速，药物不断推陈出新。小分子酪氨酸激酶抑制剂占据了其中最大的一块版图，它们往往有明确的分子靶标作为疗效预测因素，在特定分子分型的患者中表现出卓越的疗效，因此成为靶向治疗的典型代表。表皮生长因子酪氨酸激酶抑制剂厄洛替尼、吉非替尼、埃克替尼和间变性淋巴瘤激酶酪氨酸激酶抑制剂克唑替尼带来了里程碑式的进步。而近年来新一代酪氨酸激酶抑制剂在上述两类药物获得性耐药患者中又取得了巨大的成功，同时新的治疗靶点也不断涌现。本文就此对重要的药物和临床研究进行了梳理和总结，并对未来的发展做出展望。

CDK4/6 or MAPK blockade enhances efficacy of EGFR inhibition in oesophageal squamous cell carcinoma

Oesophageal squamous cell carcinoma is a deadly disease where systemic therapy has relied upon empiric chemotherapy despite the presence of genomic alterations pointing to candidate therapeutic targets, including recurrent amplification of the gene encoding receptor tyrosine kinase epidermal growth factor receptor (EGFR). Here, we demonstrate that EGFR-targeting small-molecule inhibitors have efficacy in EGFR-amplified oesophageal squamous cell carcinoma (ESCC), but may become quickly ineffective. Resistance can occur following the emergence of epithelial–mesenchymal transition and by reactivation of the mitogen-activated protein kinase (MAPK) pathway following EGFR blockade. We demonstrate that blockade of this rebound activation with MEK (mitogen-activated protein kinase kinase) inhibition enhances EGFR inhibitor-induced apoptosis and cell cycle arrest, and delays resistance to EGFR monotherapy. Furthermore, genomic profiling shows that cell cycle regulators are altered in the majority of EGFR-amplified tumours and a combination of cyclin-dependent kinase 4/6 (CDK4/6) and EGFR inhibitors prevents the emergence of resistance in vitro and in vivo. These data suggest that upfront combination strategies targeting EGFR amplification, guided by adaptive pathway reactivation or by co-occurring genomic alterations, should be tested clinically.

PC02.02 Pro Chemotherapy

PC02.02 Pro Chemotherapy

Epidermal growth factor tyrosine kinase inhibitors used in the treatment of NSCLC patients with leptomeningeal metastasis

Objective: The aim of this study was to identify the clinical features and prognostic factors of leptomeningeal metastasis (LM) in non-small cell lung cancer (NSCLC) patients undergoing treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). Methods: Twenty-five cases of NSCLC with LM, treated in our hospital during January 1, 2003 to October 31, 2013, were enrolled in this study. Medical records were reviewed for clinical features and treatments, and the survival and prognostic factors were analyzed. Results: NSCLC-LM were more common in female patients (64.0%), and most were adenocarcinomas (72.0%). Twenty (80.0%) patients underwent anti-cancer treatment, among them 17 patients underwent EGFR-TKIs treatment.The median overall survival (mOS) after the diagnosis of LM was 4.9 months for the whole group (25 cases). Patients receiving EGFR-TKIs treatment had a longer median survival than patients not receiving EGFR-TKIs (5.3 months vs. 1.2 months, P=0.022). Eleven patients who developed LM before the targeted therapy had a prolonged median survival of 8.1 months after EGFR-TKIs treatment. The univariate analysis showed that female gender and EGFR-TKIs treatment were favorable prognostic factors influencing the survival (P<0.05), while age, LM at the time of initial diagnosis, LM developed during the EGFR-TKIs treatment, whole-brain radiotherapy (WBRT), intrathecal chemotherapy, or systemic cytotoxic chemotherapy were not associated with mOS (P>0.05 for all). The multivariate analysis showed that female gender (P=0.012) and EGFR-TKIs treatment (P=0.008) were significant predictors of a good prognosis. Conclusions: EGFR-TKIs treatment may confer benefit for NSCLC-LM patients. Female patients and EGFR-TKIs treatment are favorable prognostic factors for survival.