Protein Tyrosine Phosphatase Non-Receptor 11 (PTPN11/Shp2) as a Driver Oncogene and a Novel Therapeutic Target in Non-Small Cell Lung Cancer (NSCLC)

PTPN11 encodes the SHP2 protein tyrosine phosphatase that activates the mitogen-activated protein kinase (MAPK) pathway upstream of KRAS and MEK. PTPN11/Shp2 somatic mutations occur frequently in Juvenile myelomonocytic leukaemia (JMML); however, the role of mutated PTPN11 in lung cancer tumourigenesis and its utility as a therapeutic target has not been fully addressed. We applied mass-spectrometry-based genotyping to DNA extracted from the tumour and matched the normal tissue of 356 NSCLC patients (98 adenocarcinomas (LUAD) and 258 squamous cell carcinomas (LUSC)). Further, PTPN11 mutation cases were identified in additional cohorts, including TCGA, Broad, and MD Anderson datasets and the COSMIC database. PTPN11 constructs harbouring PTPN11 E76A, A72D and C459S mutations were stably expressed in IL-3 dependent BaF3 cells and NSCLC cell lines (NCI-H1703, NCI-H157, NCI-H1299). The MAPK and PI3K pathway activation was evaluated using Western blotting. PTPN11/Shp2 phosphatase activity was measured in whole-cell protein lysates using an Shp2 assay kit. The Shp2 inhibitor (SHPi) was assessed both in vitro and in vivo in a PTPN11-mutated cell line for improved responses to MAPK and PI3K targeting therapies. Somatic PTPN11 hotspot mutations occurred in 4/98 (4.1%) adenocarcinomas and 7/258 (2.7%) squamous cells of 356 NSCLC patients. Additional 26 PTPN11 hotspot mutations occurred in 23 and 3 adenocarcinomas and squamous cell carcinoma, respectively, across the additional cohorts. Mutant PTPN11 significantly increased the IL-3 independent survival of Ba/F3 cells compared to wildtype PTPN11 (p < 0.0001). Ba/F3, NCI-H1703, and NCI-H157 cells expressing mutant PTPN11 exhibited increased PTPN11/Shp2 phosphatase activity and phospho-ERK1/2 levels compared to cells expressing wildtype PTPN11. The transduction of the PTPN11 inactivating mutation C459S into NSCLC cell lines led to decreased phospho-ERK, as well as decreased phospho-AKT in the PTPN11-mutated NCI-H661 cell line. NCI-H661 cells (PTPN11-mutated, KRAS-wild type) were significantly more sensitive to growth inhibition by the PI3K inhibitor copanlisib (IC50: 13.9 ± 4.7 nM) compared to NCI-H1703 (PTPN11/KRAS-wild type) cells (IC50: >10,000 nM). The SHP2 inhibitor, in combination with the PI3K targeting therapy copanlisib, showed no significant difference in tumour development in vivo; however, this significantly prevented MAPK pathway induction in vitro (p < 0.0001). PTPN11/Shp2 demonstrated the in vitro features of a driver oncogene and could potentially sensitize NSCLC cells to PI3K inhibition and inhibit MAPK pathway activation following PI3K pathway targeting.

A real-world study of second or later-line osimertinib in patients with EGFR T790M-positive NSCLC: the final ASTRIS data

Aim: Report the final analysis from ASTRIS, the largest real-world study of second-/later-line osimertinib in advanced/metastatic EGFR T790M non-small-cell lung cancer (NSCLC). Methods: Patients with advanced/metastatic EGFR T790M NSCLC and prior EGFR-TKI treatment, received once-daily osimertinib 80 mg. Primary end point: overall survival (OS); secondary end points: progression-free survival (PFS), time-to-treatment discontinuation (TTD) and response rate. Safety was also recorded. Results: In 3014 patients, median OS: 22.8 months (21.6-23.8), median PFS: 11.1 months (11.0-12.0), median TTD: 13.5 months (12.6-13.9), and response rate: 57.3% (55.5-59.2). All end points reported with 95% CIs . Numerically longer median OS was observed in patients with baseline WHO performance status <2 versus 2 (24.0 vs 11.1 months) and those without versus with brain/leptomeningeal metastases (25.4 vs 18.0 months). No new safety signals were identified. Conclusion: Second-/later-line osimertinib demonstrated real-world clinical benefit and safety in advanced/metastatic EGFR T790M NSCLC. Clinical Trial Registration: NCT02474355 (ClinicalTrials.gov).

Early detection of recurrent lung cancer: Enhancing-nodule in post-radiation fibrosis

Early detection of lung cancer recurrence on imaging is critical for better clinical prognosis. The ‘enhancing nodule in post-radiation fibrosis sign’ is an important sign which helps detect recurrent lung cancer early on CT chest.

The HGF/c-MET Pathway Is a Driver and Biomarker of VEGFR-inhibitor Resistance and Vascular Remodeling in Non-Small Cell Lung Cancer

Purpose: Resistance to VEGFR inhibitors is a major obstacle in the treatment of non-small cell lung cancer (NSCLC). We investigated the cellular mechanisms mediating resistance of NSCLCs to VEGFR tyrosine kinase inhibitors.Experimental Design: We generated murine models of human NSCLC and performed targeted inhibition studies with the VEGFR TKIs cediranib and vandetanib. We used species-specific hybridization of microarrays to compare cancer (human) and stromal (mouse) cell transcriptomes of TKI-sensitive and -resistant tumors. We measured tumor microvascular density and vessel tortuosity to characterize the effects of therapy on the tumor vascular bed. Circulating cytokine and angiogenic factor levels in patients enrolled in VEGFR TKI trials were correlated with clinical outcomes.Results: Murine xenograft models of human lung adenocarcinoma were initially sensitive to VEGFR TKIs, but developed resistance to treatment. Species-specific microarray analysis identified increased expression of stromal-derived hepatocyte growth factor (HGF) as a candidate mediator of TKI resistance and its receptor, c-MET, was activated in cancer cells and tumor-associated stroma. A transient increase in hypoxia-regulated molecules in the initial response phase was followed by adaptive changes resulting in a more tortuous vasculature. Forced HGF expression in cancer cells reduced tumor sensitivity to VEGFR TKIs and produced tumors with tortuous blood vessels. Dual VEGFR/c-MET signaling inhibition delayed the onset of the resistant phenotype and prevented the vascular morphology alterations. In patients with cancer receiving VEGFR TKIs, high pretreatment HGF plasma levels correlated with poorer survival.Conclusions: HGF/c-MET pathway mediates VEGFR inhibitor resistance and vascular remodeling in NSCLC. Clin Cancer Res; 23(18); 5489-501. ©2017 AACR.

Erlotinib and bevacizumab in patients with advanced non-small-cell lung cancer and activating EGFR mutations (BELIEF): an international, multicentre, single-arm, phase 2 trial

BACKGROUND

The tyrosine kinase inhibitor erlotinib improves the outcomes of patients with advanced non-small-cell lung carcinoma (NSCLC) harbouring epidermal growth factor receptor (EGFR) mutations. The coexistence of the T790M resistance mutation with another EGFR mutation in treatment-naive patients has been associated with a shorter progression-free survival to EGFR inhibition than in the absence of the T790M mutation. To test this hypothesis clinically, we developed a proof-of-concept study, in which patients with EGFR-mutant NSCLC were treated with the combination of erlotinib and bevacizumab, stratified by the presence of the pretreatment T790M mutation.

METHODS

BELIEF was an international, multicentre, single-arm, phase 2 trial done at 29 centres in eight European countries. Eligible patients were aged 18 years or older and had treatment-naive, pathologically confirmed stage IIIB or stage IV lung adenocarcinoma with a confirmed, activating EGFR mutation (exon 19 deletion or L858R mutation). Patients received oral erlotinib 150 mg per day and intravenous bevacizumab 15 mg/kg every 21 days and were tested centrally for the pretreatment T790M resistance mutation with a peptide nucleic acid probe-based real-time PCR. The primary endpoint was progression-free survival. The primary efficacy analysis was done in the intention-to-treat population and was stratified into two parallel substudies according to the centrally confirmed pretreatment T790M mutation status of enrolled patients (T790M positive or negative). The safety analysis was done in all patients that have received at least one dose of trial treatment. This trial was registered with ClinicalTrials.gov, number NCT01562028.

FINDINGS

Between June 11, 2012, and Oct 28, 2014, 109 patients were enrolled and included in the efficacy analysis. 37 patients were T790M mutation positive and 72 negative. The overall median progression-free survival was 13·2 months (95% CI 10·3-15·5), with a 12 month progression-free survival of 55% (95% CI 45-64). The primary endpoint was met only in substudy one (T790M-positive patients). In the T790M-positive group, median progression-free survival was 16·0 months (12·7 to not estimable), with a 12 month progression-free survival of 68% (50-81), whereas in the T790M-negative group, median progression-free survival was 10·5 months (9·4-14·2), with a 12 month progression-free survival of 48% (36-59). Of 106 patients included in the safety analysis, five had grade 4 adverse events (one acute coronary syndrome, one biliary tract infection, one other neoplasms, and two colonic perforations) and one died due to sepsis.

INTERPRETATION

The BELIEF trial provides further evidence of benefit for the combined use of erlotinib and bevacizumab in patients with NSCLC harbouring activating EGFR mutations.

FUNDING

European Thoracic Oncology Platform, Roche.

Abstract 376: Increased HGF is associated with resistance to VEGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC)

Emergence of therapeutic resistance to angiogenesis inhibitors, the mechanisms of which are poorly understood, remains a major obstacle in treatment of NSCLC patients. Previously we reported that mechanisms governing resistance to anti-angiogenic therapy may involve both tumor and stromal cells in the tumor microenvironment. In this study we investigated potential mechanisms of resistance to the multi-tyrosine kinase inhibitors cediranib (AZD2171, Recentin®) and vandetanib (ZD6474, Zactima®) using NSCLC xenografts treated either for 2 weeks (sensitive tumors) or until resistance occurred. Quantification of TUNEL+ staining using laser scanning cytometry (LSC) showed increased apoptosis in H1975 xenografts sensitive to cediranib (p&lt;0.01) and vandetanib (p&lt;0.05) when compared with controls, whereas no changes were noticed at time of resistance. Microvessel density (MVD) was significantly increased in resistant H1975 xenografts compared with controls (p&lt;0.05) and sensitive tumors (p&lt;0.01), whereas in A549 model, vandetanib-resistance was associated with an angiogenic independent phenotype. To investigate stromal mechanisms of Vascular Endothelial Growth Factor Receptor (VEGFR) TKI resistance, we characterized the stromal angiogenic gene expression profiles of H1975 sensitive and resistant tumors using a mouse-specific gene expression array (mouseWG-6 v2 Expression BeadChip, Illumina®). Differentially modulated genes were selected based on a p&lt;0.005 of the univariate t-test and at least a 1.5 fold-change in expression and cross-referenced to defined list(s) of angiogenesis-related genes. Stromal Hgf (hepatocyte growth factor) was up-regulated in VEGFR TKI-resistant xenografts compared to sensitive tumors. Hgf up-regulation was confirmed at the protein level using immunofluorescent staining and confocal microscopy. HGF protein levels were strongly decreased after 2 weeks of treatment with cediranib and vandetanib (p&lt;0.01), whereas a significant increase in HGF was observed in resistant xenografts (p&lt;0.01). To assess whether HGF upregulation contributes to tumor resistance to TKIs, we implanted HGF-overexpressing and vector control HCC827 NSCLC cells into nude mice. In HCC827-vector control xenografts, cediranib inhibited tumor growth by 93%, whereas a 60% of growth inhibition was observed in HGF-overexpressing tumors. These data agree favorably with our previous analysis of clinical specimens from patients with stage IIIB/IV NSCLC that identified HGF as a predictive marker of resistance to vandetanib treatment alone when compared to chemotherapy or the combination of chemotherapy and vandetanib (p=0.033). Our results suggest that HGF up-regulation may resistance to VEGFR pathway inhibition and that the HGF/MET axis may represent a crucial target for NSCLCs that are resistant to anti-angiogenic therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 376.