TKI-resistant Epidermal Growth Factor Receptor Research Articles

ASK120067 (limertinib) exerts pre-clinical anti-tumor activity by inhibiting EGFR exon20 insertion

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are classic strategies for the individualized treatment for patients with non-small cell lung cancer (NSCLC). However, EGFR exon20 insertion (EGFR 20ins) mutations, accounting for 6%–12% of all EGFR mutant cases in NSCLC, are generally resistant to the reversible EGFR TKIs (such as gefitinib and erlotinib), which makes them challenging drug-targets in lung cancer. In our previous study, we identified ASK120067 (limertinib) as a novel 3rd-generation EGFR TKI targeting EGFR T790M mutation with promising clinical activities. Here, we accessed the potency of ASK120067 on EGFR 20ins activation and evaluated its in vitro and in vivo anti-tumor activity against EGFR 20ins driven tumor models. We found that ASK120067 showed potent inhibitory activity on TKI-resistant EGFR 20ins kinase. In TKI-resistant EGFR 20ins-dependent BaF3 cells, it dose-dependently suppressed EGFR phosphorylation, impeded cell proliferation, and induced cell apoptosis with much superior efficacy to gefitinib and erlotinib. Moreover, oral administration of ASK120067 decreased the level of phospho-EGFR 20ins and caused significant tumor regression in EGFR 20ins BaF3 xenograft model. These results presented the pre-clinical anti-tumor efficacy of ASK120067 in EGFR 20ins models and highlighted the potential value of ASK120067 for the treatment of NSCLC patients harboring EGFR 20ins mutations.

The dual PI3K/mTOR inhibitor BEZ235 restricts the growth of lung cancer tumors regardless of EGFR status, as a potent accompanist in combined therapeutic regimens

BackgroundLung cancer is the most common cause of cancer-related mortality worldwide despite diagnostic improvements and the development of targeted therapies, notably including epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). The phosphoinositide 3-kinase (PI3K)/AKT/mechanistic target of rapamycin (mTOR) signaling has been shown to contribute to tumorigenesis, tumor progression, and resistance to therapy in most human cancer types, including lung cancer. Here, we explored the therapeutic effects of co-inhibition of PI3K and mTOR in non-small-cell lung cancer (NSCLC) cells with different EGFR status.MethodsThe antiproliferative activity of a dual PI3K/mTOR inhibitor BEZ235 was examined by the WST-1 assay and the soft agar colony-formation assay in 2 normal cell lines and 12 NSCLC cell lines: 6 expressing wild-type EGFR and 6 expressing EGFR with activating mutations, including exon 19 deletions, and L858R and T790 M point mutations. The combination indexes of BEZ235 with cisplatin or an EGFR-TKI, BIBW2992 (afatinib), were calculated. The mechanisms triggered by BEZ235 were explored by western blotting analysis. The anti-tumor effect of BEZ235 alone or combined with cisplatin or BIBW2992 were also studied in vivo.ResultsBEZ235 suppressed tumor growth in vitro and in vivo by inducing cell-cycle arrest at G1 phase, but without causing cell death. It also reduced the expression of cyclin D1/D3 by regulating both its transcription and protein stability. Moreover, BEZ235 synergistically enhanced cisplatin-induced apoptosis in NSCLC cells by enhancing or prolonging DNA damage and BIBW2992-induced apoptosis in EGFR-TKI–resistant NSCLC cells containing a second TKI-resistant EGFR mutant.ConclusionsThe dual PI3K/mTOR inhibition by BEZ235 is an effective antitumor strategy for enhancing the efficacy of chemotherapy or targeted therapy, even as a monotherapy, to restrict tumor growth in lung cancer treatment.

Impact of Epidermal Growth Factor Receptor Mutation on Clinical Outcomes of Nintedanib Plus Docetaxel in Patients with Previously Treated Non-Small Cell Lung Cancer from the Korean Named Patient Program

Objectives: Anti-angiogenic agents are reported to exert clinical activity on epidermal growth factor receptor (EGFR) mutant non-small-cell lung cancers. We evaluated the clinical outcomes of nintedanib and docetaxel in refractory NSCLC according to EGFR mutation status during the Korean nintedanib named patient program. Methods: Docetaxel was administered either 75 or 37.5 mg/m² on D1, D8 q every 3 weeks for 4–6 cycles plus nintedanib 200 mg orally twice daily until disease progression or unacceptable toxicity. Results: Sixty-two patients were enrolled for study. Twenty-eight patients with activating EGFR mutations progressed after EGFR-tyrosine kinase inhibitors (TKI) therapy and 25 out of 28 patients showing progression after platinum doublet chemotherapy were enrolled. The objective response rate was 29% and median PFS and OS were 3.9 months and 11.7 months. Based on the EGFR mutation status, the objective response rate was 39.3 vs. 21.9% (EGFR mut(+) vs. EGFR mut(–), p = 0.142) and median PFS was 6.5 vs. 3.3 months (EGFR mut(+) vs. EGFR mut(–), p = 0.009). No treatment-related deaths were reported. The most frequent drug-related adverse events (AE) were neutropenia (53.2%) and diarrhea (37.1%). Treatment in 12 patients (19.3%) was permanently discontinued due to AEs without disease progression. Conclusions: Our data indicated that nintedanib-docetaxel combination could be considered to be effective treatment in EGFR TKI-resistant EGFR mutant NSCLC.

Aptamer-Conjugated Chitosan-Anchored Liposomal Complexes for Targeted Delivery of Erlotinib to EGFR-Mutated Lung Cancer Cells.

Lung cancer is the leading cancer and has the highest death rate. The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) erlotinib has had a promising response in lung cancer therapy. Unfortunately, individuals with TKI-resistant EGFR mutations often develop acquired resistance against erlotinib. To overcome this resistance, in the present study, we developed liposomes anchored with anti-EGFR aptamer (Apt)-conjugated chitosan (Apt-Cs) as stable carriers to deliver erlotinib to the target. We loaded erlotinib into Apt-Cs-anchored liposomal complexes (Apt-CL-E) and characterized the physicochemistry of Apt-CL-E. The nanoparticles showed good biostability and a binding specificity for EGFR-mutated cancer cells guided by the Apt. The specific binding facilitated the uptake of Apt-CL-E into EGFR-mutated cancer cells. A cytotoxicity study showed an advantage of Apt-CL-E over their nontargeted liposomal counterparts in delivering erlotinib to EGFR-mutated cancer cells, resulting in cell cycle arrest and apoptosis. These results provide a good platform for future in vivo animal studies with Apt-CL-E.

Development of epidermal growth factor receptor tyrosine kinase inhibitors against EGFR T790M. Mutation in non small-cell lung carcinoma.

Individualized therapies targeting epidermal growth factor receptor (EGFR) mutations show promises for the treatment of non small-cell lung carcinoma (NSCLC). However, disease progression almost invariably occurs 1 year after tyrosine kinase inhibitor (TKI) treatment. The most prominent mechanism of acquired resistance involves the secondary EGFR mutation, namely EGFR T790M, which accounts for 50%–60% of resistant tumors. A large amount of studies have focused on the development of effective strategies to treat TKI-resistant EGFR T790M mutation in lung tumors. Novel generations of EGFR inhibitors are producing encouraging results in patients with acquired resistance against EGFR T790M mutation. This review will summarize the novel inhibitors, which might overcome resistance against EGFR T790M mutation.

Effect of sialylation on EGFR phosphorylation and resistance to tyrosine kinase inhibition

Epidermal growth factor receptor (EGFR) is a heavily glycosylated transmembrane receptor tyrosine kinase. Upon EGF-binding, EGFR undergoes conformational changes to dimerize, resulting in kinase activation and autophosphorylation and downstream signaling. Tyrosine kinase inhibitors (TKIs) have been used to treat lung cancer by inhibiting EGFR phosphorylation. Previously, we demonstrated that EGFR sialylation suppresses its dimerization and phosphorylation. In this report, we further investigated the effect of sialylation on the phosphorylation profile of EGFR in TKI-sensitive and TKI-resistant cells. Sialylation was induced in cancer progression to inhibit the association of EGFR with EGF and the subsequent autophosphorylation. In the absence of EGF the TKI-resistant EGFR mutant (L858R/T790M) had a higher degree of sialylation and phosphorylation at Y1068, Y1086, and Y1173 than the TKI-sensitive EGFR. In addition, although sialylation in the TKI-resistant mutants suppresses EGFR tyrosine phosphorylation, with the most significant effect on the Y1173 site, the sialylation effect is not strong enough to stop cancer progression by inhibiting the phosphorylation of these three sites. These findings were supported further by the observation that the L858R/T790M EGFR mutant, when treated with sialidase or sialyltransferase inhibitor, showed an increase in tyrosine phosphorylation, and the sensitivity of the corresponding resistant lung cancer cells to gefitinib was reduced by desialylation and was enhanced by sialylation.