GLP2-GLP2R signal affects the viability and EGFR-TKIs sensitivity of PC9 and HCC827 cells

Background The resistance to epidermal growth factor receptor (EGFR)- tyrosine kinase inhibitors (TKIs) therapy is currently the major clinical challenge in the treatment of lung cancer. This study aims to reveal the role of glucagon-like peptide (GLP) 2 and GLP-2 receptor (GLP2R) signaling on the EGFR-TKIs and cisplatin resistance of lung cancer cells. Methods The common differentially expressed genes in PC9 and HCC827 cells that were individually resistant to one of the three EGFR-TKIs (dacomitinib, osimertinib and afatinib) were screened. The data were from GSE168043 and GSE163913. The expression of GLP2R in drug-resistant cells was detected by western blot. The effect of GLP2R expression down- or up-regulation on resistance to dacomitinib, osimertinib, afatinib or cisplatin was measured by CCK-8 and flow cytometry assays. The long-acting analog of GLP-2, teduglutide, treated the parental cells. Results A total of 143 common differentially expressed genes were identified. Compared with the parent cells, the GLP2R expression in drug-resistant cell lines was significantly up-regulated. The exogenous expression of GLP2R in parental cells enhanced cell viability, while knockdown of GLP2R levels in drug-resistant cell lines inhibited cell viability. In addition, teduglutide treatment also enhanced the viability of lung cancer cells. Conclusion GLP2-GLP2R signal may change the sensitivity of cells to EGFR-TKIs and cisplatin. The development of GLP-2 or GLP2R inhibitors may be beneficial to the clinical treatment of lung cancer.

ERK inhibitor ASN007 effectively overcomes acquired resistance to EGFR inhibitor in non‐small cell lung cancer

SummaryThe emergence of acquired resistance limits the long-term efficacy of EGFR tyrosine kinase inhibitors (EGFR TKIs). Thus, development of effective strategies to overcome resistance to EGFR TKI is urgently needed. Multiple mechanisms to reactivate ERK signaling have been successfully demonstrated in acquired resistance models. We found that in EGFR mutant non-small cell lung cancer (NSCLC) patients, acquired resistance to EGFR TKIs was accompanied by increased activation of ERK. Increased ERK activation was also found in in vitro models of acquired EGFR TKI resistance. ASN007 is a potent selective ERK1/2 inhibitor with promising antitumor activity in cancers with BRAF and RAS mutations. ASN007 treatment impeded tumor cell growth and the cell cycle in EGFR TKI-resistant cells. In addition, combination treatment with ASN007 and EGFR TKIs significantly decreased the survival of resistant cells, enhanced induction of apoptosis, and effectively inhibited the growth of erlotinib-resistant xenografts, providing the preclinical rationale for testing combinations of ASN007 and EGFR TKIs in EGFR-mutated NSCLC patients. This study emphasizes the importance of targeting ERK signaling in maintaining the long-term benefits of EGFR TKIs by overcoming acquired resistance.

Comparing EGFR tyrosine kinase inhibitor treatments in EGFR-mutated non-small cell lung cancer across Asian and non-Asian patients: a plain language summary

This is a summary of a review article that looked at how people from different ethnic populations respond differently to treatments for a type of lung cancer called non-small cell lung cancer (also known as NSCLC). EGFR tyrosine kinase inhibitors (often shortened to EGFR TKI treatments) are a form of treatment for NSCLC called EGFR mutation-positive NSCLC. There are currently five EGFR TKI treatments available, which are categorized based on when they were developed. First-generation EGFR TKI treatments were developed first, followed by second-generation and then third-generation. As different people respond differently to treatments, this review looked at data from clinical studies to investigate how first-, second- and third-generation EGFR TKIs are used to treat people with NSCLC from different ethnicities. The results showed that second- and third-generation EGFR TKIs work better in treating people with NSCLC than first-generation TKIs in both Asian and non-Asian populations. However, it is still not clear whether second- or third-generation EGFR TKIs should be used as the initial treatment of choice for NSCLC, particularly in Asian patients. In one of the studies (called the FLAURA study), the third-generation EGFR TKI osimertinib improved overall survival (the length of time that patients survived, from first dose of treatment to death) when compared to first-generation EGFR TKIs. However, this was only seen in non-Asian people with NSCLC and not in Asian people with NSCLC. Saving osimertinib for second-line use (i.e., after the initial treatment has stopped working or becomes ineffective) may increase the duration of chemotherapy-free treatment, particularly in Asian patients.

EGFR-D770>GY and Other Rare EGFR Exon 20 Insertion Mutations with a G770 Equivalence Are Sensitive to Dacomitinib or Afatinib and Responsive to EGFR Exon 20 Insertion Mutant-Active Inhibitors in Preclinical Models and Clinical Scenarios

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations account for a tenth of all EGFR mutations in lung cancers. An important unmet clinical need is the identification of EGFR exon 20 insertion mutants that can respond to multiple classes of approved EGFR-TKIs. We sought to characterize variants involving EGFR-D770 to EGFR-G770 position equivalence changes that structurally allow for response to irreversible 2nd generation EGFR-TKIs. Our group used preclinical models of EGFR exon 20 insertion mutations to probe representative 1st (erlotinib), 2nd (afatinib, dacomitinib), 3rd generation (osimertinib) and EGFR exon 20 insertion mutant-active (poziotinib, mobocertinib) TKIs; we also queried the available clinical literature plus our institutional database to enumerate clinical outcomes. EGFR-D770>GY and other EGFR insertions with a G770 equivalence were identified at a frequency of 3.96% in separate cohorts of EGFR exon 20 insertion mutated lung cancer (n = 429). Cells driven by EGFR-D770>GY were insensitive to erlotinib and osimertinib, displayed sensitivity to poziotinib and dacomitinib and were uniquely sensitive to afatinib and dacomitinib in comparison with other more typical EGFR exon 20 insertion mutations using proliferation and biochemical assays. Clinical cases with EGFR-G770 equivalence from the literature and our center mirrored the preclinical data, with radiographic responses and clinical benefits restricted to afatinib, dacomitinib, poziotinib and mobocertinib, but not to erlotinib or osimertinib. Although they are rare, at <4% of all exon 20 insertion mutations, EGFR-G770 equivalence exon 20 insertion mutations are sensitive to approved 2nd generation EGFR TKIs and EGFR exon 20 insertion mutant-active TKIs (mobocertinib and poziotinib). EGFR-D770>GY and other insertions with a G770 equivalence join EGFR-A763_Y764insFQEA as exon 20 insertion mutationsresponsive to approved EGFR TKIs beyond mobocertinib; this data should be considered for clinical care, genomic profiling reports and clinical trial elaboration.

Observational Study of Re-Biopsy in EGFR-TKI-Resistant Patients with EGFR Mutation-Positive Advanced NSCLC

Identification of acquired resistant mutation has been essential in non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) active mutations. Re-biopsy plays a pivotal role to select the optimal treatment for patients who develop resistance to initial EGFR-tyrosine kinase inhibitors (EGFR-TKIs). This multicenter, observational study was conducted to investigate the details of re-biopsy in Japanese clinical practice.The primary endpoints were the implementation rate of re-biopsy and the concordance rate for the T790M mutation detection between histology and cytology specimens using the Cobas ® EGFR mutation test v2. 194 patients with EGFR-mutant NSCLC were enrolled and 120 patients developed acquired resistance to EGFR-TKIs. The median age was 68 years (range 20-87), and 52.5% of the patients were women. Re-biopsy was performed on 109 patients with the implementation rate of re-biopsy was 90.8%. The success rate of re-biopsy in total/histology/cytology/liquid biopsy population was 78.0%, 94.9%, 83.3% and 43.8%, respectively. The positive percent agreement and the negative percent agreement in the detection of T790M mutations between the histology and cytology specimens was both of 90.9%. Aggressive obtaining histological or cytological tissue samples at re-biopsy may contribute to improvement of the detection rate of T790M mutation. (trial registration number: UMIN000026019)

Real-World Pattern of Treatment and Clinical Outcomes of EGFR-Mutant Non-Small Cell Lung Cancer in a Single Academic Centre in Quebec

The discovery of EGFR tyrosine kinase inhibitors (TKI) for the treatment of EGFR mutant (EGFRm) metastatic NSCLC is regarded as a landmark in lung cancer. EGFR-TKIs have now become a standard first-line treatment for EGFRm NSCLC. The aim of this retrospective cohort study is to describe real-world patterns of treatment and treatment outcomes in patients with EGFRm metastatic NSCLC who received EGFR-TKI therapy outside of clinical trials. One hundred and seventy EGFRm metastatic NSCLC patients were diagnosed and initiated on first-line TKI therapy between 2004 and 2018 at the Peter Brojde Lung Cancer Centre in Montreal. Following progression of the disease, 137 (80%) patients discontinued first-line treatment. Moreover, 80/137 (58%) patients received second-line treatment, which included: EGFR-TKIs, platinum-based, or single-agent chemotherapy. At the time of progression on first-line treatment, 73 patients were tested for the T790M mutation. Moreover, 30/73 (41%) patients were found to be positive for the T790M mutation; 62/80 patients progressed to second-line treatment and 20/62 were started on third-line treatment. The median duration of treatment was 11.5 (95% CI; 9.62–13.44) months for first-line treatment, and 4.4 (95% CI: 1.47–7.39) months for second-line treatment. Median OS from the time of diagnosis of metastatic disease was 23.5 months (95% CI: 16.9–30.1) and median OS from the initiation of EGFR-TKI was 20.6 months (95% CI: 13.5–27.6). We identified that ECOG PS ≤ 2, presence of exon 19 deletion mutation, and absence of brain metastases were associated with better OS. A significant OS benefit was observed in patients treated with osimertinib in second-line treatment compared to those who never received osimertinib. Overall, our retrospective observational study suggests that treatment outcomes in EGFRm NSCLC in real-world practice, such as OS and PFS, reflect the result of RCTs. However, given the few observational studies on real-world treatment patterns of EGFR-mutant NSCLC, this study is important for understanding the potential impact of EGFR-TKIs on survival outside of clinical trials. Further real-world studies are needed to characterize patient outcomes for emerging therapies, including first-line osimertinib use and combination of osimertinib with chemotherapy and potential future combination of osimertinib and novel anticancer drug, outside of a clinical trial setting.

DDX3X mediates EGFR-TKI resistance through VEGFR signaling

Although epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are remarkably effective against non-small-cell lung cancer (NSCLC) with EGFR-activating mutations, lung cancer cells acquire resistance to EGFR-TKIs without exception. Several mechanisms of EGFR-TKI resistance have been reported, but there are many aspects that remain to be clarified. We previously identified DDX3X as an immunogenic protein preferentially expressed in murine melanoma with a cancer stem cell (CSC)-like phenotype. DDX3X induced epithelial-mesenchymal transition and reduced the sensitivity to EGFR-TKIs in PC9 cells, human lung cancer cells harboring EGFR exon 19 deletion. We also reported that there was a small nonadherent subpopulation of parental PC9 cells that highly expressed DDX3X and had CSC properties. In this study, we found that VEGFR2 was upregulated in lung cancer cells that strongly expressed DDX3X and that these cells were addicted to VEGFR signaling. The blockade of both EGFR and VEGFR signaling reduced the phosphorylation of downstream signals in the cells with DDX3X that acquired EGFR-TKI resistance. The addition of VEGFR-TKIs or anti-VEGF antibodies to EGFR-TKIs significantly inhibited the progression of EGFR-mutated NSCLC in a xenograft mouse model. These data suggest that the blockade of VEGFR signaling enhances the antitumor effects of EGFR-TKIs by eradicating cancer stem cells, which mediate resistance to EGFR-TKIs.