Hsp90 inhibitors enhance the antitumoral effect of osimertinib in parental and osimertinib-resistant non-small cell lung cancer cell lines

Background: Osimertinib improve therapy for non-small cell lung cancer (NSCLC). However, invariable acquired resistance appears. Methods: MTT assay was used to analyze cell viability. Protein expression and activation was detected by Western blotting. In addition, the effects of heat shock protein 90 (Hsp90) inhibitors and osimertinib were studied in colony formation assays. Results: Our laboratory generated osimertinib resistant cell lines from PC9 cell line and overexpression or activation of several proteins was detected. Hsp90 inhibitors, ganetespib and luminespib, inhibited cell viability and colony formation in H1975, PC9 and PC9-derived osimertinib-resistant cell lines and combination of these inhibitors with osimertinib achieved to enhance this cell viability and colony formation inhibition. Luminespib downregulated the expression of the several proteins involved in osimertinib-resistance and the combination of this compound plus osimertinib caused an important decrease of expression of several of these proteins, such as Stat3, Yap, Akt, EGFR and Met. Osimertinib activated the phosphorylation of several membrane receptors and downstream molecules that was partially inhibited by luminespib. In addition, a lung cancer patient with an EGFR eon 20 mutation had a partial radiographic response to ganetespib. Conclusions: Hsp90 inhibitors and osimertinib exhibits a good efficiency to inhibit cell viability, colony formation and inhibits expression and activation of proteins involved in osimertinib-resistance and may represent an effective strategy for NSCLC with intrinsic resistance to osimertinib inhibition

Targeting PKC iota-PAK1 signaling pathways in EGFR and KRAS mutant adenocarcinoma and lung squamous cell carcinoma

Introduction: p21-activated kinase 1 (PAK1) stimulates growth and metastasis in non-small cell lung cancer (NSCLC). Protein kinase C iota (PKC iota) is an enzyme highly expressed in NSCLC, regulating PAK1 signaling. In the present study we explored whether the PKC iota-PAK1 signaling pathway approach can be an efficient target in different types of NSCLC cell and mouse models. Methods: The effect of IPA-3 (PAK1 inhibitor) plus auranofin (PKC iota inhibitor) combination was evaluated by cell viability assay, colony formation and western blotting assay, using three types of NSCLC cell lines: EGFR or KRAS mutant adenocarcinoma and squamous cell carcinoma with PAK1 amplification. In addition, for clinical availability, screening for new PAK1 inhibitors was carried out and the compound OTSSP167 was evaluated in combination with auranofin in cell and mice models. Results: The combination of IPA-3 or OTSSP167 plus auranofin showed high synergism for inhibiting cell viability and colony formation in three cell lines. Mechanistic characterization revealed that this drug combination abrogated expression and activation of membrane receptors and downstream signaling proteins crucial in lung cancer: EGFR, MET, PAK1, PKC iota, ERK1/2, AKT, YAP1 and mTOR. A nude mouse xenograft assay demonstrated that this drug combination strongly suppressed tumor volume compared with single drug treatment. Conclusions: Combination of IPA-3 or OTSSP167 and auranofin was highly synergistic in EGFR or KRAS mutant adenocarcinoma and squamous cell carcinoma cell lines and decreased tumor volume in mice models. It is of interest to further test the targeting of PKC iota-PAK1 signaling pathways in EGFR mutant, KRAS mutant and squamous NSCLC patients

BIM and mTOR expression levels predict outcome to erlotinib in EGFR-mutant non-small-cell lung cancer

Altres ajuts: Fellowship Award of the International Association for the Study of Lung Cancer i grant of the Italian Association for Cancer Research (AIRC My First AIRC Grant n° 14282).Abstract.BIM is a proapoptotic protein that initiates apoptosis triggered by EGFR tyrosine kinase inhibitors (TKI). mTOR negatively regulates apoptosis and may influence response to EGFR TKI. We examined mRNA expression of BIM and MTOR in 57 patients with EGFR-mutant NSCLC from the EURTAC trial. Risk of mortality and disease progression was lower in patients with high BIM compared with low/intermediate BIM mRNA levels. Analysis of MTOR further divided patients with high BIM expression into two groups, with those having both high BIM and MTOR experiencing shorter overall and progression-free survival to erlotinib. Validation of our results was performed in an independent cohort of 19 patients with EGFR-mutant NSCLC treated with EGFR TKIs. In EGFR-mutant lung adenocarcinoma cell lines with high BIM expression, concomitant high mTOR expression increased IC50 of gefitinib for cell proliferation. We next sought to analyse the signalling pattern in cell lines with strong activation of mTOR and its substrate P-S6. We showed that mTOR and phosphodiesterase 4D (PDE4D) strongly correlate in resistant EGFR-mutant cancer cell lines. These data suggest that the combination of EGFR TKI with mTOR or PDE4 inhibitors could be adequate therapy for EGFR-mutant NSCLC patients with high pretreatment levels of BIM and mTOR

Convergent Akt activation drives acquired EGFR inhibitor resistance in lung cancer

EGFR-mutant non-small cell lung cancer are often resistant to EGFR tyrosine kinase inhibitor treatment. In this study, the authors show that resistant tumors display high Akt activation and that a combined treatment with AKT inhibitors causes synergistic tumour growth inhibition in vitro and in vivo

Vaccine antibodies against a synthetic epidermal growth factor variant enhance the antitumor effects of inhibitors targeting the MAPK/ERK and PI3K/Akt pathways

We thank Isabel Crespo and Sara Ozcoz from the Cytomics Core Facility of the Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) for technical assistance. The study was funded by grants from IN3BIO.Background: The EGFR pathway is involved in intrinsic and acquired resistance to a wide variety of targeted therapies in cancer. Vaccination represents an alternative to the administration of anti-EGFR monoclonal antibodies, such as cetuximab or panitumumab. Here, we tested if anti-EGF antibodies generated by vaccination (anti-EGF VacAbs) could potentiate the activity of drugs targeting the ERK/MAPK and PI3K/Akt pathways. Methods: Non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and melanoma cell lines harboring KRAS, NRAS, BRAF and PIK3CA mutations were used. Anti-EGF VacAbs were obtained by immunizing rabbits with a fusion protein containing a synthetic, highly mutated variant of human EGF. Cell viability was determined by MTT, total and phosphorylated proteins by Western blotting, cell cycle distribution and cell death by flow cytometry and emergence of resistance by microscopic examination in low density cultures. Results: Anti-EGF VacAbs potentiated the antiproliferative effects of MEK, KRAS G12C, BRAF, PI3K and Akt inhibitors in KRAS, NRAS, BRAF and PIK3CA mutant cells and delayed the appearance of resistant clones in vitro. The effects of anti-EGF VacAbs were comparable or superior to those of panitumumab and cetuximab. The combination of anti-EGF VacAbs with the targeted inhibitors effectively suppressed EGFR downstream pathways and sera from patients immunized with an anti-EGF vaccine also blocked activation of EGFR effectors. Conclusions: Anti-EGF VacAbs enhance the antiproliferative effects of drugs targeting the ERK/MAPK and PIK3CA/Akt pathways. Our data provide a rationale for clinical trials testing anti-EGF vaccination combined with inhibitors selected according to the patient's genetic profile

Co-activation of STAT3 and YES-Associated Protein 1 (YAP1) Pathway in EGFR-Mutant NSCLC

Background: The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR-mutant non–small cell lung cancer (NSCLC) is limited by adaptive activation of cell survival signals. We hypothesized that both signal transducer and activator of transcription 3 (STAT3) and Src-YES-associated protein 1 (YAP1) signaling are dually activated during EGFR TKI treatment to limit therapeutic response. Methods: We used MTT and clonogenic assays, immunoblotting, and quantitative polymerase chain reaction to evaluate the efficacy of EGFR TKI alone and in combination with STAT3 and Src inhibition in three EGFR-mutant NSCLC cell lines. The Chou-Talalay method was used for the quantitative determination of drug interaction. We examined tumor growth inhibition in one EGFR-mutant NSCLC xenograft model (n = 4 mice per group). STAT3 and YAP1 expression was evaluated in tumors from 119 EGFR-mutant NSCLC patients (64 in an initial cohort and 55 in a validation cohort) by quantitative polymerase chain reaction. Kaplan-Meier and Cox regression analyses were used to assess the correlation between survival and gene expression. All statistical tests were two-sided. Results: We discovered that lung cancer cells survive initial EGFR inhibitor treatment through activation of not only STAT3 but also Src-YAP1 signaling. Cotargeting EGFR, STAT3, and Src was synergistic in two EGFR-mutant NSCLC cell lines with a combination index of 0.59 (95% confidence interval [CI] = 0.54 to 0.63) for the PC-9 and 0.59 (95% CI = 0.54 to 0.63) for the H1975 cell line. High expression of STAT3 or YAP1 predicted worse progression-free survival (hazard ratio [HR] = 3.02, 95% CI = 1.54 to 5.93, P = .001, and HR = 2.57, 95% CI = 1.30 to 5.09, P = .007, respectively) in an initial cohort of 64 EGFR-mutant NSCLC patients treated with firstline EGFR TKIs. Similar results were observed in a validation cohort. Conclusions: Our study uncovers a coordinated signaling network centered on both STAT3 and Src-YAP signaling that limits targeted therapy response in lung cancer and identifies an unforeseen rational upfront polytherapy strategy to minimize residual disease and enhance clinical outcomes

Src-Homology 2 Domain-Containing Phosphatase 2 in Resected EGFR Mutation-Positive Lung Adenocarcinoma

Funding: supported by a La Caixa Foundation grant and the Spanish Association Against Cancer (PROYE18012ROSE)EGFR mutation-positive lung adenocarcinoma (LUAD) displays impaired phosphorylation of ERK and Src-homology 2 domain-containing phosphatase 2 (SHP2) in comparison with EGFR wild-type LUADs. We hypothesize that SHP2 expression could be predictive in patients positive with resected EGFR mutation versus patients with EGFR wild-type LUAD. We examined resected LUAD cases from Japan and Spain. mRNA expression levels of AXL, MET, CDCP1, STAT3, YAP1, and SHP2 were analyzed by quantitative reverse transcriptase polymerase chain reaction. The activity of SHP2 inhibitors plus erlotinib were tested in EGFR -mutant cell lines and analyzed by cell viability assay, Western blot, and immunofluorescence. A total of 50 of 100 EGFR mutation-positive LUADs relapsed, among them, patients with higher SHP2 mRNA expression revealed shorter progression-free survival, in comparison with those having low SHP2 mRNA (hazard ratio: 1.83; 95% confidence interval: 1.05-3.23; p = 0.0329). However, SHP2 was not associated with prognosis in the remaining 167 patients with wild-type EGFR. In EGFR -mutant cell lines, the combination of SHP099 or RMC-4550 (SHP2 inhibitors) with erlotinib revealed synergism via abrogation of phosphorylated AKT (S473) and ERK1/2 (T202/Y204). Although erlotinib translocates phosphorylated SHP2 (Y542) into the nucleus, either RMC-4550 alone, or in combination with erlotinib, relocates SHP2 into the cytoplasm membrane, limiting AKT and ERK1/2 activation. Elevated SHP2 mRNA levels are associated with recurrence in resected EGFR mutation-positive LUADs, but not in EGFR wild-type. EGFR tyrosine kinase inhibitors can enhance SHP2 activation, hindering adjuvant therapy. SHP2 inhibitors could improve the benefit of adjuvant therapy in EGFR mutation-positive LUADs

KRAS-mutant non-small cell lung cancer (NSCLC) therapy based on tepotinib and omeprazole combination

Background KRAS-mutant non-small cell lung cancer (NSCLC) shows a relatively low response rate to chemotherapy, immunotherapy and KRAS-G12C selective inhibitors, leading to short median progression-free survival, and overall survival. The MET receptor tyrosine kinase (c-MET), the cognate receptor of hepatocyte growth factor (HGF), was reported to be overexpressed in KRAS-mutant lung cancer cells leading to tumor-growth in anchorage-independent conditions. Methods Cell viability assay and synergy analysis were carried out in native, sotorasib and trametinib-resistant KRAS-mutant NSCLC cell lines. Colony formation assays and Western blot analysis were also performed. RNA isolation from tumors of KRAS-mutant NSCLC patients was performed and KRAS and MET mRNA expression was determined by real-time RT-qPCR. In vivo studies were conducted in NSCLC (NCI-H358) cell-derived tumor xenograft model. Results Our research has shown promising activity of omeprazole, a V-ATPase-driven proton pump inhibitor with potential anti-cancer properties, in combination with the MET inhibitor tepotinib in KRAS-mutant G12C and non-G12C NSCLC cell lines, as well as in G12C inhibitor (AMG510, sotorasib) and MEK inhibitor (trametinib)-resistant cell lines. Moreover, in a xenograft mouse model, combination of omeprazole plus tepotinib caused tumor growth regression. We observed that the combination of these two drugs downregulates phosphorylation of the glycolytic enzyme enolase 1 (ENO1) and the low-density lipoprotein receptor-related protein (LRP) 5/6 in the H358 KRAS G12C cell line, but not in the H358 sotorasib resistant, indicating that the effect of the combination could be independent of ENO1. In addition, we examined the probability of recurrence-free survival and overall survival in 40 early lung adenocarcinoma patients with KRAS G12C mutation stratified by KRAS and MET mRNA levels. Significant differences were observed in recurrence-free survival according to high levels of KRAS mRNA expression. Hazard ratio (HR) of recurrence-free survival was 7.291 (p = 0.014) for high levels of KRAS mRNA expression and 3.742 (p = 0.052) for high MET mRNA expression. Conclusions We posit that the combination of the V-ATPase inhibitor omeprazole plus tepotinib warrants further assessment in KRAS-mutant G12C and non G12C cell lines, including those resistant to the covalent KRAS G12C inhibitors

HMGB1 Expression Levels Correlate with Response to Immunotherapy in Non-Small Cell Lung Cancer

Maria González-Cao,1 Xueting Cai,2 Jilian Wilhelmina Paulina Bracht,3 Xuan Han,2 Yang Yang,2 Carlos Pedraz-Valdunciel,4 Teresa Morán,5 Javier García-Corbacho,6 Andrés Aguilar,1 Reyes Bernabé,7 Pedro De Marchi,8,9 Luciane Sussuchi da Silva,8 Leticia Ferro Leal,8 Rui Manuel Reis,8,10,11 Jordi Codony-Servat,4 Eloisa Jantus-Lewintre,12– 14 Miguel Angel Molina-Vila,4 Peng Cao,2,15 Rafael Rosell1,16 1Translational Cancer Research Unit, Instituto Oncológico Dr Rosell, Dexeus University Hospital, Barcelona, Spain; 2Integrated Traditional Chinese and Western Medicine Department of Affiliated Hospital, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, People’s Republic of China; 3Amsterdam University Medical Center (UMC), Amsterdam, The Netherlands; 4Laboratory of Oncology, Pangaea Oncology, Quirón Dexeus University Hospital, Barcelona, Spain; 5Medical Oncology Department, Catalan Institute of Oncology (ICO), Germans Trias i Pujol Hospital, Badalona, Spain; 6Medical Oncology Department (Hospital Clinic)/Translational Genomics and Targeted Therapies in Solid Tumors (IDIBAPs), Barcelona, Spain; 7Medical Oncology Department, Hospital Universitario Virgen del Rocío, Sevilla, Spain; 8Molecular Oncology Research Center; Barretos Cancer Hospital, Barretos, Brazil; 9Oncoclinicas, Rio de Janeiro, Brazil; 10Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; 11ICVS/3b’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal; 12Valencian Community Foundation Principe Felipe Research Center, Laboratory of Molecular Oncology, Valencia, Spain; 13Centro de Investigación Biomédica en Red (CIBERONC), Madrid, Spain; 14Universitat Politècnica de Valencia, Biotechnology Department, Valencia, Spain; 15College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, People’s Republic of China; 16Laboratory of Molecular Biology, Germans Trias i Pujol Health Sciences Institute and Hospital (IGTP), Badalona, SpainCorrespondence: Rafael Rosell, Laboratory of Molecular Biology, Germans Trias i Pujol Health Sciences Institute and Hospital (IGTP), Camí de les Escoless/n, Badalona, Barcelona, 08916, Spain, Tel +34 930330520, Email [email protected] Peng Cao, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, People’s Republic of China, Tel +86 85608666, Email [email protected]: High-mobility group box 1 protein (HMGB1) is subject to exportin 1 (XPO1)-dependent nuclear export, and it is involved in functions implicated in resistance to immunotherapy. We investigated whether HMGB1 mRNA expression was associated with response to immune checkpoint inhibitors (ICI) in non-small cell lung cancer (NSCLC).Patients and Methods: RNA was isolated from pretreatment biopsies of patients with advanced NSCLC treated with ICI. Gene expression analysis of several genes, including HMGB1, was conducted using the NanoString Counter analysis system (PanCancer Immune Profiling Panel). Western blotting analysis and cell viability assays in EGFR and KRAS mutant cell lines were carried out. Evaluation of the antitumoral effect of ICI in combination with XPO1 blocker (selinexor) and trametinib was determined in a murine Lewis lung carcinoma model.Results: HMGB1 mRNA levels in NSCLC patients treated with ICI correlated with progression-free survival (PFS) (median PFS 9.0 versus 18.0 months, P=0.008, hazard ratio=0.30 in high versus low HMGB1). After TNF-α stimulation, HMGB1 accumulates in the cytoplasm of PC9 cells, but this accumulation can be prevented by using selinexor or antiretroviral drugs. Erlotinib or osimertinib with selinexor in EGFR-mutant cells and trametinib plus selinexor in KRAS mutant abolish tumor cell proliferation. Selinexor with a PD-1 inhibitor with or without trametinib abrogates the tumor growth in the murine Lewis lung cancer model.Conclusion: An in-depth exploration of the functions of HMGB1 mRNA and protein is expected to uncover new potential targets and provide a basis for treating metastatic NSCLC in combination with ICI.Keywords: HMGB1, immunotherapy, non-small cell lung cancer, Lewis lung cancer murine model, K-Ras mutation