The complexity of EGFR exon 19 deletion and L858R mutant cells as assessed by proteomics, transcriptomics, and metabolomics

Multieffect Specific Nanovesicles for Homing Resistant Tumors and Overcoming Osimertinib-Acquired Resistance in NSCLC

Acquired resistance to osimertinib (Osi) remains a major obstacle in the treatment of patients with EGFR-mutant non-small cell lung cancer (NSCLC). AXL elevation is a known key mechanism of Osi-resistance, and therapeutic strategies remain scarce. Emerging evidence reveals that an increased intracellular glutathione (GSH) level induces Osi resistance. In this study, a new mechanism is identified by which GSH regulates AXL expression via glutathione peroxidase 4 (GPX4) in Osi-resistant cells. A multifunctional covalent organic framework (COF) nanoplatform for GSH consumption, AXL inhibition, and co-delivery of the AXL inhibitor (Brigatinib) and Osi is creatively constructed to confirm whether Osi sensitivity improves by simultaneously targeting GSH-AXL resistance mechanisms. Furthermore, it is coated, for the first time, the COF carrier system with specific vesicles to precisely home it into resistant tumors, where CDH2 adhesion molecules play a crucial role. The engineered multifunctional antiresistance-specific nanovesicles effectively inhibited the GSH-AXL axis, induced apoptosis in Osi-resistant cells both in vitro and in vivo, and delayed the progression of Osi-resistant tumors. Overall, these findings provide a novel strategy to overcome the Osi-acquired resistance caused by high AXL levels in NSCLC.

Distinguishing MPLCs from IPMs using NGS-based molecular algorithms and histological assessment: A systematic review and validation study

Distinguishing between multiple primary lung cancers and intrapulmonary metastases is crucial for staging, therapeutic planning, and prognosis. Traditional histological assessment provides a foundation for diagnosis, which can be limited when tumors showed identical or similar histological types. This systematic review and independent validation study aimed to evaluate the performance of next-generation sequencing (NGS)-based molecular algorithms alongside histological methods for the classification of multiple lung adenocarcinomas (MLAs). We conducted a literature search to identify relevant studies and selected algorithms for validation using a cohort of patients with MLAs. Our analysis included 27 patients with MLAs and compared histological assessment using Martini and Melamed criteria and comprehensive histologic assessment combined with a low-grade lepidic component (CHA & lepidic) with NGS data. We found a high consistency between CHA & lepidic and NGS-based diagnoses, although some discrepancies remained, particularly in cases with no somatic mutations or distant metastases. NGS-based molecular algorithms offer a high degree of accuracy in determining the origin of MLAs, supporting or challenging histological diagnoses. However, histological methods remain valuable, especially when NGS data are inconclusive. This study underscores the complementary nature of histology and molecular diagnostics in the precise classification of MLAs.

The combined inhibition of SLC1A3 and glutaminase in osimertinib-resistant EGFR mutant cells

BACKGROUND

We investigated the unknown mechanisms of osimertinib-resistant EGFR-mutant lung cancer.

METHODS

An osimertinib-resistant cell line (PC-9/OsmR2) was established through continuous exposure to osimertinib using an EGFR exon 19 deletion (19Del) lung adenocarcinoma cell line (PC-9). EGFR 19Del (M1), L858R/T790M/C797S (M6), and L858R/C797S (M8) expression vectors were introduced into Ba/F3 cells. A second osimertinib-resistant line (M1/OsmR) was established through continuous exposure to osimertinib using M1 cells.

RESULTS

SLC1A3 had the highest mRNA expression level in PC-9/OsmR2 compared to PC-9 cells by microarray analysis and SLC1A3 was increased by flow cytometry. In PC-9/OsmR2 cells, osimertinib sensitivity was significantly increased in combination with siSLC1A3. Because SLC1A3 functions in glutamic acid transport, osimertinib with a glutaminase inhibitor (CB-839) or an SLC1A3 inhibitor (TFB-TBOA) increased the sensitivity. Also, CB-839 plus TFB-TBOA without osimertinib resulted in greater susceptibility than did CB-839 or TFB-TBOA plus osimertinib. Comprehensive metabolome analysis showed that the M1/OsmR cells had significantly more glutamine and glutamic acid than M1 cells. CB-839 plus osimertinib exerted a synergistic effect on M6 cells and an additive effect on M8 cells.

CONCLUSION

Targeting glutaminase and glutamic acid may overcome the osimertinib-resistant EGFR-mutant lung cancer.

A novel molecular target, superoxide dismutase 1, in ALK inhibitor-resistant lung cancer cells, detected through proteomic analysis

BACKGROUNDS

To the best of our knowledge, there are no reports of proteomic analysis for the identification of unknown proteins involved in resistance to anaplastic lymphoma kinase (ALK) inhibitors. In this study, we investigated the proteins involved in resistance to alectinib, a representative ALK inhibitor, through proteomic analysis and the possibility of overcoming resistance.

METHODS

An ALK-positive lung adenocarcinoma cell line (ABC-11) and the corresponding alectinib-resistant cell line (ABC-11/CHR2) were used. Two-dimensional difference gel electrophoresis (2D DIGE) was performed; the stained gel was scanned and the spots were analyzed using DeCyder TM2D 7.0. Mass spectrometry (MS) with the UltrafleXtreme matrix-assisted laser desorption ionization-tandem time-of-flight (MALDI-TOF/TOF) MS system was performed. For the MS/MS analysis, the samples were spotted on an AnchorChipTM 600 TF plate. The peptide masses obtained in the reflector positive mode were acquired at m/z of 400-6000. MS/MS data were searched against the NCBI protein databases. Growth inhibition was measured using an MTT assay. The isobologram and combination index were calculated based on the median-effect analysis. Western blotting was performed using antibodies, including superoxide dismutase (SOD) 1, MET, ERK, PARP, AKT, and BRCA1.

RESULTS

The 2D DIGE for ABC-11 and ABC-11/CHR2 showed different expression levels in about 2000 spots. SOD was identified from spots highly expressed in resistant strains. Western blotting also confirmed SOD1 overexpression in ABC-11/CHR2. siSOD1 enhanced the growth inhibitory effects of alectinib, increased cleaved PARP levels, and decreased pERK, pAKT, and BRCA1 levels with a combination of alectinib. In addition, the combination of LCS-1, an SOD1 inhibitor, and alectinib synergistically suppressed the growth in ABC-11/CHR2, but not in ABC-11.

CONCLUSIONS

SOD1 overexpression is thought to be a mechanism for alectinib resistance, suggesting the possibility of overcoming resistance using SOD1 inhibitors.

Mechanism of targeting the mTOR pathway to regulate ferroptosis in NSCLC with different EGFR mutations

Patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR)-activating mutations can be treated with EGFR-tyrosine kinase inhibitors (TKIs). Although EGFR-TKI-targeted drugs bring survival promotion in patients with EGFR mutations, drug resistance is inevitable, so it is urgent to explore new treatments to overcome drug resistance. In addition, wild-type EGFR lacks targeted drugs, and new targeted therapies need to be explored. Ferroptosis is a key research direction for overcoming drug resistance. However, the role and mechanism of regulating ferroptosis in different EGFR-mutant NSCLC types remains unclear. In the present study, H1975 (EGFR T790M/L858R mutant), A549 (EGFR wild-type) and H3255 (EGFR L858R mutant) NSCLC cell lines were used. The expression of ferroptosis markers in these cell lines was detected using western blotting and reverse transcription-quantitative PCR. Cell viability was determined using the MTT assay and reactive oxygen species (ROS) levels were measured using flow cytometry. The results showed that, compared with EGFR wild-type/sensitive mutant cells, EGFR-resistant mutant cells were more sensitive to the ferroptosis inducer, erastin. Furthermore, the mammalian target of rapamycin (mTOR) inhibitor, everolimus (RAD001), induced cell death in all three cell lines in a dose-dependent manner. The ferroptosis inhibitor, ferrostatin-1, could reverse cell death in EGFR-resistant mutant and EGFR wild-type cells induced by RAD001, but could not reverse cell death in EGFR-sensitive mutant cells. Compared with EGFR wild-type/sensitive mutant cells, EGFR-resistant mutant cells were more sensitive to RAD001 combined with erastin. In addition, a high-dose of RAD001 reduced the expression levels of ferritin heavy-chain polypeptide 1 (FTH1), glutathione peroxidase 4 (GPX4) and ferroportin and significantly increased ROS and malondialdehyde (MDA) levels in EGFR-resistant mutant and EGFR wild-type cells. In the present study, GPX4 inhibitor only or combined with RAD001 inhibited the AKT/mTOR pathway in EGFR-resistant mutant cells. Therefore, the results of the present study suggested that inhibition of the mTOR pathway may downregulate the expression of ferroptosis-related proteins in EGFR-resistant and EGFR wild-type NSCLC cells, increase the ROS and MDA levels and ultimately induce ferroptosis.

Perioperative Treatment Strategies in EGFR-Mutant Early-Stage NSCLC: Current Evidence and Future Challenges

Treatment with 3 years of adjuvant osimertinib is considered a new standard in patients with completely resected stage I to IIIA NSCLC harboring a common sensitizing EGFR mutation. This therapeutic approach significantly prolonged the disease-free survival and the overall survival versus placebo and revealed a significant role in preventing the occurrence of brain metastases. However, many unanswered questions remain, including the optimal duration of this therapy, whether all patients benefit from adjuvant osimertinib, and the role of adjuvant chemotherapy in this population. Indeed, there is a renewed interest in neoadjuvant strategies with targeted therapies in resectable NSCLC harboring oncogenic drivers. In light of these considerations, we discuss the past and current treatment options, and the clinical challenges that should be addressed to optimize the treatment outcomes in this patient population.