A case of EGFR mutant lung adenocarcinoma that acquired resistance to EGFR-tyrosine kinase inhibitors with MET amplification and epithelial-to-mesenchymal transition

Clinical Impact of the Epithelial-Mesenchymal Transition in Lung Cancer as a Biomarker Assisting in Therapeutic Decisions

Lung cancer is one of the most common solid cancers and represents the leading cause of cancer death worldwide. Over the last decade, research on the epithelial-mesenchymal transition (EMT) in lung cancer has gained increasing attention. Here, we review clinical and histological features of non-small-cell lung cancer associated with EMT. We then aimed to establish potential clinical implications of EMT in current therapeutic options, including surgery, radiation, targeted therapy against oncogenic drivers, and immunotherapy.

Crizotinib with or without an EGFR-TKI in treating EGFR-mutant NSCLC patients with acquired MET amplification after failure of EGFR-TKI therapy: a multicenter retrospective study

Background

MET amplification is associated with acquired resistance to first-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in treating non-small-cell lung cancer (NSCLC); however, the therapeutic strategy in these patients is undefined. Herein we report the clinical outcomes of patients with c-MET amplification resistance to EGFR-TKIs treated with crizotinib.

Methods

We retrospectively analyzed advanced NSCLC patients from five sites who were diagnosed with EGFR-mutant NSCLC and received EGFR-TKI treatment. After disease progression, these patients were confirmed to have a MET-to-centromere ratio (MET:CEN) ≥ 1.8 based on fluorescence in situ hybridization (FISH) examination and without a T790M mutation. We assessed the efficacy and safety of crizotinib to overcome EGFR-TKI resistance in EGFR-activating mutations NSCLC with acquired MET amplification.

Results

Amplification of the acquired MET gene was identified in 18 patients with EGFR-mutant NSCLC. Fourteen patients received crizotinib treatment after acquired resistance to EGFR-TKIs. Among the 14 patients, 6 (42.9%) received crizotinib plus EGFR-TKI and 8 (57.1%) received crizotinib monotherapy. The overall objective response rate (ORR) and disease control rate (DCR) were 50.0% (7/14) and 85.7% (12/14), respectively. The median PFS (mPFS) of patients receiving crizotinib monotherapy and crizotinib plus EGFR-TKI was 6.0 and 12.6 months, respectively (P = 0.315). Notably, treatment efficacy was more pronounced in patients with crizotinib than patients with chemotherapy (24.0 months vs. 12.0 months, P = 0.046). The mOS for 8 of 14 patients receiving crizotinib monotherapy and 6 of 14 patients receiving crizotinib plus EGFR-TKI was 17.2 and 24.0 months, respectively (P = 0.862). Among the 14 patients, 1 who received crizotinib monotherapy (grade 3 nausea) and 2 who received crizotinib plus EGFR-TKI (grade 3 elevated liver aminotransferase levels) received reduced doses of crizotinib (200 mg twice daily) to better tolerate the dose.

Conclusions

We observed the clinical evidence of efficacy generated by combination of crizotinib and previous EGFR-TKIs after the resistance to first-generation EGFR-TKIs. These results might increase evidence of more effective therapeutic strategies for NSCLC treatment. Combination therapy did not increase the frequency of adverse reactions.

MET amplification increases the metastatic spread of EGFR-mutated NSCLC

BACKGROUND

Five to 20% of metastatic EGFR-mutated non-small cell lung cancers (NSCLC) develop acquired resistance to EGFR tyrosine kinase inhibitors (EGFR-TKI) through MET amplification. The effects of MET amplification on tumor and patient phenotype remain unknown.

METHODS

We investigated,in vitro and in vivo, the impact of MET amplification on the biological properties of the HCC827 cell line, derived from an EGFR-mutated NSCLC. We further evaluated the time to new metastases after EGFR-TKI progression in EGFR-mutated NSCLC, exhibiting MET amplification or high MET overexpression.

RESULTS

MET amplification significantly enhanced proliferation, anchorage independent growth, anoikis resistance, migration, and induced an epithelial to mesenchymal transition. In vivo, MET amplification significantly increased the tumor growth and metastatic spread. Treatment with a MET-TKI reversed this aggressive phenotype. We found that EGFR-mutated NSCLC patients exhibiting MET amplification on a re-biopsy, performed after EGFR-TKI progression, displayed a shorter time to new metastases after EGFR-TKI progression than patients with high MET overexpression but no MET amplification.

CONCLUSION

MET amplification increases metastatic spread even in the context of an already pre-existing strong driver mutation such as EGFR mutation. These results prompt development of therapeutic strategies aiming at preventing emergence of MET amplification.

Role of artemin in non-small cell lung cancer

Background

In this study, we investigated the role of artemin, a member of the glial cell‐derived neurotrophic factor of ligands, in the malignant phenotype of lung cancer.

Methods

Artemin expression was examined in various types of lung cancer and normal lung tissues, as well as in lung cancer cell lines by immunohistochemistry and semi‐quantitative PCR. Functional studies were performed using artemin overexpression or knockdown vectors in lung cancer cell lines. Methyl thiazolyl tetrazolium, flow cytometry, wound healing, and transwell assays were conducted to evaluate the contribution of artemin on tumor cell proliferation, migration, and invasion.

Results

Artemin is broadly expressed in lung cancer tissues, and is associated with tumor staging. Overexpression of artemin in NL9980 large cell lung cancer cells increased proliferating cells and enhanced migrating capability in wound healing and transwell assays, as well as demonstrating enhanced invasion capability. Silencing artemin in LTEP‐α‐2 adenocarcinoma cell lines decreased cellular proliferation, migration, and invasion capabilities.

Conclusion

Artemin could promote the proliferation and invasiveness of lung cancer cells in vitro and therefore could be a new potential target to combat lung cancer.

Long non-coding RNA BC087858 induces non-T790M mutation acquired resistance to EGFR-TKIs by activating PI3K/AKT and MEK/ERK pathways and EMT in non-small-cell lung cancer

Our previous study demonstrated that long non-coding RNA (lncRNA) BC087858 could stimulate acquired resistance to EGFR-TKIs in non-small cell lung (NSCLC) but the specific regulatory mechanism remained unknown. We aimed to explore the role and mechanism of lncRNA BC087858 on EGFR-TKIs acquired resistance. LncRNA BC087858 mRNA expression was detected by reverse transcription polymerase chain reaction in different NSCLC cell lines and tissues. The relationship between BC087858 expression and clinicopathological factors was performed by Cox multivariate regression analysis. Small-interfering RNA, flow cytometry and trans-well assay were conducted to explore the biological functions of BC087858. Western blotting was used to analyze the target proteins expression. Over-expression was observed in NSCLC cells and patients with acquired resistance to EGFR-TKIs and significantly associated with a shorter progression-free survival (PFS) (12.0 vs. 17.0 months, P = 0.0217) in tumors with respond to EGFR-TKIs. The significant relationship was not observed in patients with T790M mutation (median PFS 17.6 vs. 12.5 months, P = 0.522) but in patients with non-T790M (median PFS 8.0 vs. 18.25 months,P = 0.0427). Down-regulation of BC087858 could significantly promote PC9/R and PC9/G2 cells invasion (P < 0.05; respectively). BC087858 knockdown restored gefitinib sensitivity in acquired resistant cells with non-T790M and inhibited the activation of the PI3K/AKT and MEK/ERK pathways and epithelial-mesenchymal transition (EMT) via up- regulating ZEB1 and Snail. In conclusion, LncRNA BC087858 could promote cells invasion and induce non-T790M mutation acquired resistance to EGFR-TKIs by activating PI3K/AKT and MEK/ERK pathways and EMT via up- regulating ZEB1 and Snail in NSCLC.

Progression inference for somatic mutations in cancer

Computational methods were employed to determine progression inference of genomic alterations in commonly occurring cancers. Using cross-sectional TCGA data, we computed evolutionary trajectories involving selectivity relationships among pairs of gene-specific genomic alterations such as somatic mutations, deletions, amplifications, downregulation, and upregulation among the top 20 driver genes associated with each cancer. Results indicate that the majority of hierarchies involved TP53, PIK3CA, ERBB2, APC, KRAS, EGFR, IDH1, VHL, etc. Research into the order and accumulation of genomic alterations among cancer driver genes will ever-increase as the costs of nextgen sequencing subside, and personalized/precision medicine incorporates whole-genome scans into the diagnosis and treatment of cancer.