Circ_0001786 facilitates gefitinib resistance and malignant progression in non-small cell lung cancer via miR-34b-5p/SRSF1.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a widespread cancer and gefitinib is a primary therapy for NSCLC patients. Nevertheless, the underlying mechanisms for the progression of acquired drug resistance have not been clarified. The aim of this study was to investigate the role of circular RNA (circ_0001786) in gefitinib-resistant NSCLC. METHODS: Firstly, the expression of circ_0001786, miR-34b-5p and SRSF1 were assayed using qRT-PCR. Subsequently, CCK-8 test was utilized to measure the semi-inhibitory concentration (IC50) of cellular gefitinib. Apoptosis was identified by flow cytometry. At last, dual luciferase assay was applied to prove the binding association between miR-34b-5p, circ_0001786 or SRSF1. RESULTS: Our research disclosed that circ_0001786 was heightened in gefitinib-resistant NSCLC cells and tissues. Knockdown of circ_0001786 restrained IC50 values of gefitinib, attenuated the clonogenic ability and facilitated apoptosis in HCC827-GR and PC9-GR. In addition, circ_0001786 was a molecular sponge for miR-34b-5p. Silencing miR-34b-5p rescued the inhibitory impact of circ_0001786 knockdown on IC50 and cell cloning ability. Moreover, miR-34b-5p directly targeted SRSF1. Importantly, circ_0001786 enhanced gefitinib tolerance and malignant development in NSCLC through miR-34b-5p/SRSF1 pathway. CONCLUSION: This research revealed a novel mechanism by which circ_0001786 enhanced NSCLC resistance to gefitinib by sponging miR-34b-5p and upregulating SRSF1. circ_0001786 was a potential target for improving the treatment of gefitinib-resistant NSCLC patients.

Genome-wide CRISPR screens identify the YAP/TEAD axis as a driver of persister cells in EGFR mutant lung cancer.

Most lung cancer patients with metastatic cancer eventually relapse with drug-resistant disease following treatment and EGFR mutant lung cancer is no exception. Genome-wide CRISPR screens, to either knock out or overexpress all protein-coding genes in cancer cell lines, revealed the landscape of pathways that cause resistance to the EGFR inhibitors osimertinib or gefitinib in EGFR mutant lung cancer. Among the most recurrent resistance genes were those that regulate the Hippo pathway. Following osimertinib treatment a subpopulation of cancer cells are able to survive and over time develop stable resistance. These 'persister' cells can exploit non-genetic (transcriptional) programs that enable cancer cells to survive drug treatment. Using genetic and pharmacologic tools we identified Hippo signalling as an important non-genetic mechanism of cell survival following osimertinib treatment. Further, we show that combinatorial targeting of the Hippo pathway and EGFR is highly effective in EGFR mutant lung cancer cells and patient-derived organoids, suggesting a new therapeutic strategy for EGFR mutant lung cancer patients.

Discovery of gefitinib-1,2,3-triazole derivatives against lung cancer via inducing apoptosis and inhibiting the colony formation.

A series of 20 novel gefitinib derivatives incorporating the 1,2,3-triazole moiety were designed and synthesized. The synthesized compounds were evaluated for their potential anticancer activity against EGFR wild-type human non-small cell lung cancer cells (NCI-H1299, A549) and human lung adenocarcinoma cells (NCI-H1437) as non-small cell lung cancer. In comparison to gefitinib, Initial biological assessments revealed that several compounds exhibited potent anti-proliferative activity against these cancer cell lines. Notably, compounds 7a and 7j demonstrated the most pronounced effects, with an IC50 value of 3.94 ± 0.17 µmol L-1 (NCI-H1299), 3.16 ± 0.11 µmol L-1 (A549), and 1.83 ± 0.13 µmol L-1 (NCI-H1437) for 7a, and an IC50 value of 3.84 ± 0.22 µmol L-1 (NCI-H1299), 3.86 ± 0.38 µmol L-1 (A549), and 1.69 ± 0.25 µmol L-1 (NCI-H1437) for 7j. These two compounds could inhibit the colony formation and migration ability of H1299 cells, and induce apoptosis in H1299 cells. Acute toxicity experiments on mice demonstrated that compound 7a exhibited low toxicity in mice. Based on these results, it is proposed that 7a and 7j could potentially be developed as novel drugs for the treatment of lung cancer.

From osimertinib to preemptive combinations.

Here, I suggest that while first-line osimertinib extends median progression-free survival (PFS) in EGFR-mutant lung cancer compared to first-generation TKIs, it reduces individual PFS in 15-20% of patients compared to first-generation TKIs. Since detecting a single resistant cell before treatment is usually impossible, osimertinib must be used in all patients as a first-line treatment, raising median PFS overall but harming some. The simplest remedy is a preemptive combination (PC) of osimertinib and gefitinib. A comprehensive PC (osimertinib, afatinib/gefitinib, and capmatinib) could dramatically increase PFS for 80% of patients compared to osimertinib alone, without harming anyone. This article also explores PCs for MET-driven lung cancer.

Simultaneous determination of 11 oral targeted antineoplastic drugs and 2 active metabolites by LC-MS/MS in human plasma and its application to therapeutic drug monitoring in cancer patients.

Interindividual exposure differences have been identified in oral targeted antineoplastic drugs (OADs) owing to the pharmacogenetic background of the patients and their susceptibility to multiple factors, resulting in insufficient efficacy or adverse effects. Therapeutic drug monitoring (TDM) can prevent sub-optimal concentrations of OADs and improve their clinical treatment. This study aimed to develop and validate an LC-MS/MS method for the simultaneous quantification of 11 OADs (gefitinib, imatinib, lenvatinib, regorafenib, everolimus, osimertinib, sunitinib, tamoxifen, lapatinib, fruquintinib and sorafenib) and 2 active metabolites (N-desethyl sunitinib and Z-endoxifen) in human plasma. Protein precipitation was used to extract OADs from the plasma samples. Chromatographic separation was performed using an Eclipse XDB-C18 (4.6 × 150 mm, 5 µm) column with a gradient elution of the mobile phase composed of 2 mM ammonium acetate with 0.1 % formic acid in water (solvent A) and methanol (solvent B) at a flow rate of 0.8 mL/min. Mass analysis was performed using positive ion mode electrospray ionization in multiple-reaction monitoring mode. The developed method was validated following FDA bioanalytical guidelines. The calibration curves were linear over the range of 2-400 ng/mL for gefitinib, imatinib, lenvatinib, regorafenib, and everolimus; 1-200 ng/mL for osimertinib, sunitinib, N-desethyl sunitinib, tamoxifen, and Z-endoxifen; and 5-1000 ng/mL for lapatinib, fruquintinib, and sorafenib, with all coefficients of correlation above 0.99. The intra- and inter-day imprecision was below 12.81 %. This method was successfully applied to the routine TDM of gefitinib, lenvatinib, regorafenib, osimertinib, fruquintinib, and sorafenib to optimize the dosage regimens.

Activation of epidermal growth factor receptors in triple-negative breast cancer cells by morphine; analysis through Raman spectroscopy and machine learning.

Triple negative breast cancer (TNBC) is a very aggressive form of breast cancer, and the analgesic drug morphine has been shown to promote the proliferation of TNBC cells. This article investigates whether morphine causes activation of epidermal growth factor receptors (EGFR), the roles of µ-opioid and EGFR receptors on TNBC cell proliferation and migration. While examining the changes with molecular techniques, we also aimed to investigate the analysis ability of Raman spectroscopy and machine learning-based approach. Effects of morphine on the proliferation and migration of MDA.MB.231 cells were evaluated by MTT and scratch wound-healing tests, respectively. Morphine-induced phosphorylation of the EGFR was analyzed by western blotting in the presence and absence of µ-receptor antagonist naltrexone and the EGFR-tyrosine kinase inhibitor gefitinib. Morphine-induced EGFR phosphorylation and cell migration were significantly inhibited by pretreatments with both naltrexone and gefitinib; however, morphine-increased cell proliferation was inhibited only by naltrexone. While morphine-induced changes were observed in the Raman scatterings of the cells, the inhibitory effect of naltrexone was analyzed with similarity to the control group. Principal component analysis (PCA) of the Raman confirmed the epidermal growth factor (EGF)-like effect of morphine and was inhibited by naltrexone and partly by gefitinib pretreatments. Our in vitro results suggest that combining morphine with an EGFR inhibitor or a peripherally acting opioidergic receptor antagonist may be a good strategy for pain relief without triggering cancer proliferation and migration in TNBC patients. In addition, our results demonstrated the feasibility of the Raman spectroscopy and machine learning-based approach as an effective method to investigate the effects of agents in cancer cells without the need for complex and time-consuming sample preparation. The support vector machine (SVM) with linear kernel automatically classified the effects of drugs on cancer cells with ∼95% accuracy.

YES1 as a potential target to overcome drug resistance in EGFR-deregulated non-small cell lung cancer.

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) such as gefitinib and osimertinib have primarily been used as first-line treatments for patients with EGFR-activating mutations in non-small cell lung cancer (NSCLC). Novel biomarkers are required to distinguish patients with lung cancer who are resistant to EGFR-TKIs. The aim of the study is to investigate the expression and functional role of YES1, one of the Src-family kinases, in EGFR-TKI-resistant NSCLC. YES1 expression was elevated in gefitinib-resistant HCC827 (HCC827/GR) cells, harboring EGFR mutations. Moreover, HCC827/GR cells exhibited increased reactive oxygen species (ROS) levels compared to those of the parent cells, resulting in the phosphorylation/activation of YES1 due to oxidation of the cysteine residue. HCC827/GR cells showed elevated expression levels of YES1-associated protein 1 (YAP1), NF-E2-related factor 2 (Nrf2), cancer stemness-related markers, and antioxidant proteins compared to those of the parent cells. Knockdown of YES1 in HCC827/GR cells suppressed YAP1 phosphorylation, leading to the inhibition of Bcl-2, Bcl-xL, and Cyclin D1 expression. Silencing YES1 markedly attenuated the proliferation, migration, and tumorigenicity of HCC827/GR cells. Dasatinib inhibited the proliferation of HCC827/GR cells by targeting YES1-mediated signaling pathways. Furthermore, the combination of gefitinib and dasatinib demonstrated a synergistic effect in suppressing the proliferation of HCC827/GR cells. Notably, YES1- and Nrf2-regulated genes showed a positive regulatory relationship in patients with lung cancer and in TKI-resistant NSCLC cell lines. Taken together, these findings suggest that modulation of YES1 expression and activity may be an attractive therapeutic strategy for the treatment of drug-resistant NSCLC.

Synergistic anti-tumor effects of lenalidomide and gefitinib by upregulating ADRB2 and inactivating the mTOR/PI3K/AKT signaling pathway in lung adenocarcinoma.

Gefitinib is commonly used to be the first-line therapy for advanced non-small cell lung cancer (NSCLC). Therapeutic effect of gefitinib is reduced due to acquired resistance, and combined treatment is recommended. In this research, we planned to explore the impacts of combined treatment of lenalidomide and gefitinib on gefitinib-sensitive or -resistant NSCLC cells. The co-treatment results demonstrated that enhanced antitumor impact on NSCLC cell growth, migration, invasion, cell cycle process and apoptosis. The tumor-bearing mouse models were established using PC9/GR cells. In vivo assays also showed that lenalidomide and gefitinib synergistically inhibited mouse tumor growth along increased the survival of mice. ADRB2 was identified as a lowly expressed gene in PC9/GR cells and LUAD tumor tissues. LUAD patients with high ADRB2 expression were indicated with favorable survival outcomes. Moreover, ADRB2 was upregulated in lenalidomide and/or gefitinib-treated PC9/GR cells. ADRB2 deficiency partially offsets the suppressive impacts of lenalidomide and gefitinib co-treatment on the viability and proliferation of PC9/GR cells. Additionally, lenalidomide and gefitinib cotreatment significantly inactivated the mTOR/PI3K/AKT signaling pathway compared with each treatment alone. Rescue assays were performed to explore whether lenalidomide and gefitinib synergistically inhibited the growth of PC9/GR cells via the PI3K/AKT pathway. PI3K activator SC79 significantly restored reduced cell proliferation, migration and invasion along with elevated cell cycle arrest and apoptosis caused by lenalidomide and gefitinib cotreatment. In conclusion, lenalidomide and gefitinib synergistically suppressed LUAD progression and attenuated gefitinib resistance by upregulating ADRB2 and inactivating the mTOR/PI3K/AKT signaling pathway in lung adenocarcinoma.

Study of cell and drug interactions based on dual-mode detection using SPR and fluorescence imaging.

The investigation of the interactions between cells and drugs forms a crucial aspect of biological and clinical medical studies. Generally, single-cell or local-cellular studies require a microscopic imaging system with high magnifications, which suffers from low detection throughputs and poor time responses. The study presented in this paper combined SPR and fluorescence to achieve cell localization, real-time monitoring of cell images and quantitative analysis of drugs. In order to obtain more comprehensive, accurate and real-time data, a dual-mode system based on surface plasmon resonance (SPR) and fluorescence was constructed based on a 4× magnification lens. This enables simultaneous studies of an entire cell and a specific region of the cell membrane. An adaptive adjustment algorithm was established for distorted SPR images, achieving temporal and spatial matching of the dual-mode detection. The combination of SPR and fluorescence not only achieved micro-detection but also complemented the qualitative or quantitative limitations of SPR or fluorescence method alone. In system characterization, the response signal of SPR was noticed to increase with the increasing concentration of EGF in stimulated cells. It indicated that this platform could be employed for quantitative detection of the cell membrane region. Upon addition of EGF, a peak in the SPR curve was observed, and the cells in the corresponding SPR image turned whiter. This indicated that the platform can simultaneously monitor the SPR response signal and image changes. The response time of fluorescence in EGF testing was several seconds earlier than SPR, revealing that signal transduction first occurred in the whole cell and then propagated to the cell membrane region. The inhibitory ability of Gefitinib on cells was verified in a fast and real-time manner within 20 min. The results indicated that the detection limit of this method was 20 IU/mL for EGF and 10 µg/mL for Gefitinib. In conclusion, this study demonstrates the advantages of SPR and fluorescence dual-mode techniques in the analysis of cell-drug interactions, as well as their strong potential in drug screening.

New oxadiazole and pyrazoline derivatives as anti-proliferative agents targeting EGFR-TK: design, synthesis, biological evaluation and molecular docking study.

Two new series of oxadiazole and pyrazoline derivatives were designed and synthesized as promising EGFR-TK inhibitors. The in vitro antiproliferative activity was studied against three human cancer cell lines; HCT116, HepG-2 and MCF7 using MTT assay. Compound 10c showed the most potent anticancer activity against all cancer cell lines, with IC50 range of 1.82 to 5.55 µM, while proving safe towards normal cells WI-38 (IC50 = 41.17 µM) compared to the reference drug doxorubicin (IC50 = 6.72 µM). The most active candidates 5a, 9b, 10a, 10b and 10c were further assessed for their EGFR-TK inhibition. The best of which, compounds 5a and 10b showed IC50 of 0.09 and 0.16 µM respectively compared to gefitinib (IC50 = 0.04 µM). Further investigation against other EGFR family members, showed that 5a displayed good activities against HER3 and HER4 with IC50 values 0.18 and 0.37 µM, respectively compared to gefitinib (IC50 = 0.35 and 0.58 µM, respectively). Furthermore, 5a was evaluated for cell cycle distribution and apoptotic induction on HepG-2 cells. It induced mitochondrial apoptotic pathway and increased accumulation of ROS. Molecular docking study came in agreement with the biological results. Compounds 5a and 10b showed promising drug-likeness with good physicochemical properties.

[Mechanism of n-butanol fraction of Wenxia Formula combining with gefitinib in treating non-small cell lung cancer based on network pharmacology and in vitro experiment].

This study combined network pharmacology, molecular docking, and in vitro experiments to explore the potential mechanism of the active components of the n-butanol fraction of Wenxia Formula(NWXF) combined with gefitinib(GEF) in treating non-small cell lung cancer(NSCLC). Ultra-performance liquid chromatography-quadrupole Orbitrap mass spectrometry(UPLC-Q-Orbitrap MS) was employed to detect the main chemical components of NWXF. The active components of NWXF were retrieved from SwissADME, and the candidate targets of these active components were retrieved from SwissTargetPrediction. Online Mendelian Inheritance in Man(OMIM) and GeneCards were searched for the targets of NSCLC. Cytoscape 3.9.0 and STRING were employed to build the protein-protein interaction(PPI) network with the common targets shared by NWXF and NSCLC. Gene Ontology(GO) annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment were performed in DAVID to predict the potential mechanisms. Finally, molecular docking between the main active ingredients and key targets was conducted in SYBYL-X 2.0. The methyl thiazolyl tetrazolium(MTT) assay was employed to evaluate the inhibitory effects of NWXF and/or GEF on the proliferation of human non-small cell lung cancer cells(A549 and PC-9). Additionally, the impact of NWXF on human embryonic lung fibroblast cells(MRC-5) was assessed. The effectiveness of the drug combination was evaluated based on the Q value. The terminal-deoxynucleoitidyl transferase mediated nick-end labeling(TUNEL) assay was employed to examine the apoptosis of A549 and PC-9 cells treated with NWXF and/or GEF. Quantitative real-time PCR(qRT-PCR) was employed to measure the mRNA levels of epidermal growth factor receptor(EGFR), c-Jun N-terminal kinase(JNK), and Bcl2-associated X protein(Bax) in the A549 and PC-9 cells treated with NWXF and/or GEF. Western blot was employed to determine the protein levels of EGFR, p-EGFR, JNK, p-JNK, and Bax in the A549 and PC-9 cells treated with NWXF and/or GEF. A total of 77 active components, 488 potential targets, and 49 key targets involved in the treatment of NSCLC with NWXF were predicted. The results of GO annotation showed that NWXF may treat NSCLC by regulating the biological processes such as cell proliferation, apoptosis, and protein phosphorylation. KEGG enrichment revealed that the key targets of NWXF in treating NSCLC were enriched in the mitogen-activated protein kinase(MAPK), phosphatidylinositol 3-kinase(PI3K)-protein kinase B(AKT), hypoxia-inducible factor-1(HIF-1), and microRNA-related signaling pathways. Molecular docking results showed that 91.9% of the docking scores were greater than 5, indicating the strong binding capability between main active components and key targets. The cell experiments demonstrated that NWXF combined with GEF synergistically inhibited the proliferation, promoted the apoptosis, decreased p-EGFR/EGFR and p-JNK/JNK values, down-regulated the mRNA levels of EGFR and JNK, and up-regulated the mRNA and protein levels of Bax in A549 and PC-9 cells. In conclusion, NWXF combined with GEF can regulate the EGFR/JNK pathway to promote the apoptosis of NSCLC cells, thus treating NSCLC.

[Combination of shikonin and gefitinib reverses drug resistance in human non-small cell lung cancer and its mechanism].

The occurrence and development of tumors are associated with the cell energy metabolism. Inhibiting energy metabolism of lung cancer cells is an important strategy to overcome drug resistance. Based on the cellular energy metabolism pathway, this study observed the effect of combination of shikonin(SKN) and gefitinib(GFB) on the drug resistance in non-small cell lung cancer and explored the underlying mechanism. The human non-small cell lung cancer line HCC827/GR resistant to gefitinib was used as the cell model in vitro. The CCK-8 assay and flow cytometry were employed to investigate the cell viability and apoptosis, respectively. The high performance liquid chromatography was employed to measure the intracellular accumulation of GFB. A Seahorse XFe96 Analyzer was used to detect the changes of cellular energy metabolism. Western blot was employed to determine the expression of the proteins involved in the drug resistance. The tumor-bearing nude mouse model was used to verify the efficacy of SKN+GFB in overcoming drug resistance in vivo. The results showed that SKN+GFB significantly reduced the IC_(50) of GFB on HCC827/GR cells, with the combination index of 0.628, indicating that the combination of the two drugs had a synergistic effect and promoted cell apoptosis. SKN increased the intracellular accumulation of GFB. SKN+GFB lowered the oxygen consumption rate(OCR) and glycolytic proton efflux rate(GlycoPER) in cell energy metabolism, and down-regulated the overexpression of PKM2, p-EGFR, P-gp, and HIF-1α in drug resistance. The results of reversing drug resistance test in vivo showed that GFB or SKN alone had no significant antitumor effect, while the combination at different doses induced the apoptosis of the tumor tissue and inhibited the expression of PKM2 and P-gp, demonstrating a significant antitumor effect. Moreover, the tumor inhibition rate in the high-dose combination group reached 64.01%. In summary, SKN+GFB may interfere with the energy metabolism to limit the function of HCC827/GR cells, thus reversing the GFB resistance in non-small cell lung cancer.

Synthesis and In Vitro Antitumor Activity Evaluation of Gefitinib-1,2,3-Triazole Derivatives.

In this study, 14 structurally novel gefitinib-1,2,3-triazole derivatives were synthesized using a click chemistry approach and characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry (HRMS). Preliminary cell counting kit-8 results showed that most of the compounds exhibit excellent antitumor activity against epidermal growth factor receptor wild-type lung cancer cells NCI-H1299, A549 and NCI-H1437. Among them, 4b and 4c showed the most prominent inhibitory effects. The half maximal inhibitory concentration (IC50) values of 4b were 4.42 ± 0.24 µM (NCI-H1299), 3.94 ± 0.01 µM (A549) and 1.56 ± 0.06 µM (NCI-1437). The IC50 values of 4c were 4.60 ± 0.18 µM (NCI-H1299), 4.00 ± 0.08 µM (A549) and 3.51 ± 0.05 µM (NCI-H1437). Furthermore, our results showed that 4b and 4c could effectively inhibit proliferation, colony formation and cell migration in a concentration-dependent manner, as well as induce apoptosis in H1299 cells. In addition, 4b and 4c exerted its anti-tumor effects by inducing cell apoptosis, upregulating the expression of cleaved-caspase 3 and cleaved-PARP and downregulating the protein levels of Bcl-2. Based on these results, it is suggested that 4b and 4c be developed as potential new drugs for lung cancer treatment.

ELK1/MTOR/S6K1 Pathway Contributes to Acquired Resistance to Gefitinib in Non-Small Cell Lung Cancer.

The development of acquired resistance to small molecule tyrosine kinase inhibitors (TKIs) targeting epidermal growth factor receptor (EGFR) signaling has hindered their efficacy in treating non-small cell lung cancer (NSCLC) patients. Our previous study showed that constitutive activation of the 70 kDa ribosomal protein S6 kinase 1 (S6K1) contributes to the acquired resistance to EGFR-TKIs in NSCLC cell lines and xenograft tumors in nude mice. However, the regulatory mechanisms underlying S6K1 constitutive activation in TKI-resistant cancer cells have not yet been explored. In this study, we recapitulated this finding by taking advantage of a gefitinib-resistant patient-derived xenograft (PDX) model established through a number of passages in mice treated with increasing doses of gefitinib. The dissociated primary cells from the resistant PDX tumors (PDX-R) displayed higher levels of phosphor-S6K1 expression and were resistant to gefitinib compared to cells from passage-matched parental PDX tumors (PDX-P). Both genetic and pharmacological inhibition of S6K1 increased sensitivity to gefitinib in PDX-R cells. In addition, both total and phosphorylated mechanistic target of rapamycin kinase (MTOR) levels were upregulated in PDX-R and gefitinib-resistant PC9G cells. Knockdown of MTOR by siRNA decreased the expression levels of total and phosphor-S6K1 and increased sensitivity to gefitinib in PDX-R and PC9G cells. Moreover, a transcription factor ELK1, which has multiple predicted binding sites on the MTOR promoter, was also upregulated in PDX-R and PC9G cells, while the knockdown of ELK1 led to decreased expression of MTOR and S6K1. The chromatin immunoprecipitation (ChIP)-PCR assay showed the direct binding between ELK1 and the MTOR promoter, and the luciferase reporter assay further indicated that ELK1 could upregulate MTOR expression through tuning up its transcription. Silencing ELK1 via siRNA transfection improved the efficacy of gefitinib in PDX-R and PC9G cells. These results support the notion that activation of ELK1/MTOR/S6K1 signaling contributes to acquired resistance to gefitinib in NSCLC. The findings in this study shed new light on the mechanism for acquired EGFR-TKI resistance and provide potential novel strategies by targeting the ELK1/MTOR/S6K1 pathway.

Overall Survival From the EORTC LCG-1613 APPLE Trial of Osimertinib Versus Gefitinib Followed by Osimertinib in Advanced EGFR-Mutant Non-Small-Cell Lung Cancer.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Osimertinib has been established as a standard of care for patients with common sensitizing EGFR-mutant advanced non-small-cell lung cancer (NSCLC) although the sequential approach (first-generation inhibitor gefitinib followed by osimertinib) has not been formally compared. The phase II APPLE trial (ClinicalTrials.gov identifier: NCT02856893) enrolled 156 treatment-naïve patients, and two treatment strategies were evaluated: osimertinib up front or the sequential treatment approach with gefitinib up front followed by osimertinib at the time of progression, either molecular progression (detection of plasma T790M resistance mutation) regardless of the radiologic status or just at the time of radiologic progression. Patients' characteristics were well balanced, except for the higher proportion of baseline brain metastases in the sequential approach (29% v 19%). Per protocol, 73% of patients switched to osimertinib in the sequential arm. Up-front treatment with osimertinib was associated with a lower risk of brain progression versus the sequential approach (hazard ratio [HR], 0.54 [90% CI, 0.34 to 0.86]), but a comparable overall survival was observed between both strategies (HR, 1.01 [90% CI, 0.61 to 1.68]), with the 18-month survival probability of 84% and 82.3%, respectively. The APPLE trial suggests that a sequential treatment approach is associated with more frequent progression in the brain but a similar survival in advanced EGFR-mutant NSCLC.

Chidamide improves gefitinib treatment outcomes in NSCLC by attenuating recruitment and immunosuppressive function of myeloid-derived suppressor cells.

Clinical resistance to EGFR tyrosine kinase inhibitors in non-small-cell lung cancer (NSCLC) remains a significant challenge. Recent studies have indicated that the number of myeloid-derived suppressor cells (MDSCs) increases following gefitinib treatment, correlating with a poor patient response in NSCLC. Our study revealed that gefitinib treatment stimulates the production of CCL2, which subsequently enhances monocyte (M)-MDSC migration to tumor sites. Chidamide, a selective inhibitor of the histone deacetylase subtype, counteracted the gefitinib-induced increase in CCL2 levels in tumor cells. Additionally, chidamide down-regulated the expression of CCR2 in M-MDSCs, inhibiting their migration. Furthermore, chidamide attenuated the immunosuppressive function of M-MDSCs both alone and in combination with gefitinib. Chidamide also alleviated tumor immunosuppression by reducing the number of M-MDSCs in LLC-bearing mice, thereby enhancing the antitumor efficacy of gefitinib. In conclusion, our findings suggest that chidamide can improve gefitinib treatment outcomes, indicating that MDSCs are promising targets in NSCLC.

The novel miR-873-5p-YWHAE-PI3K/AKT axis is involved in non-small cell lung cancer progression and chemoresistance by mediating autophagy.

Non-small cell lung cancer (NSCLC) encompasses approximately 85% of all lung cancer cases and is the foremost cancer type worldwide; it is prevalent in both sexes and known for its high fatality rate. Expanding scientific inquiry underscores the indispensability of microRNAs in NSCLC. Here, we probed the impact of miR-873-5p on NSCLC development and chemoresistance. qRT‒PCR was used to measure the miR-873-5p level in NSCLC cells with or without chemoresistance. A model of miR-873-5p overexpression was constructed. The proliferation and viability of NSCLC cells were evaluated through CCK8 and colony formation experiments. Cell migration and invasion were monitored via Transwell assays. Western blotting was used to determine the levels of YWHAE, PI3K, AKT, EMT, apoptosis, and autophagy-related proteins. The sensitivity of NSCLC cells to the chemotherapeutic agent gefitinib was assessed. Additionally, the correlation of YWHAE with miR-873-5p was validated via a dual-luciferase reporter assay and RNA immunoprecipitation (RIP). Overexpressed miR-873-5p suppressed migration, proliferation, invasion, and EMT while concurrently stimulating apoptotic processes. miR-873-5p was downregulated in NSCLC cells resistant to gefitinib. Upregulating miR-873-5p reversed gefitinib resistance by inducing autophagy. YWHAE was confirmed to be a downstream target of miR-873-5p. YWHAE overexpression promoted the malignant behaviors of NSCLC cells and boosted tumor growth, while these effects were reversed following miR-873-5p overexpression. Subsequent investigations revealed that overexpressing YWHAE promoted PI3K/AKT pathway activation, with miR-873-5p displaying inhibitory effects on the YWHAE-mediated PI3K/AKT signaling cascade. miR-873-5p affects proliferation, invasion, migration, EMT, autophagy, and chemoresistance in NSCLC by controlling the YWHAE/PI3K/AKT axis.

Leucine Zipper Downregulated in Cancer-1 Interacts with Clathrin Adaptors to Control Epidermal Growth Factor Receptor (EGFR) Internalization and Gefitinib Response in EGFR-Mutated Non-Small Cell Lung Cancer.

The epidermal growth factor receptor (EGFR) is a common driver of non-small cell lung cancer (NSCLC). Clathrin-mediated internalization (CMI) sustains EGFR signaling. AXL is associated with resistance to EGFR-tyrosine kinase inhibitors (TKIs) in EGFR-mutated (EGFRM) NSCLC. We investigated the effects of Leucine zipper downregulated in cancer-1 (LDOC1) on EGFR CMI and NSCLC treatment. Coimmunoprecipitation, double immunofluorescence staining, confocal microscopy analysis, cell surface labelling assays, and immunohistochemistry studies were conducted. We revealed that LDOC1 interacts with clathrin adaptors through binding motifs. LDOC1 depletion promotes internalization and plasma membrane recycling of EGFR in EGFRM NSCLC PC9 and HCC827 cells. Membranous and cytoplasmic EGFR decreased and increased, respectively, in LDOC1 (-) NSCLC tumors. LDOC1 depletion enhanced and sustained activation of EGFR, AXL, and HER2 and enhanced activation of HER3 in PC9 and HCC827 cells. Sensitivity to first-generation EGFR-TKIs (gefitinib and erlotinib) was significantly reduced in LDOC1-depleted PC9 and HCC827 cells. Moreover, LDOC1 downregulation was significantly associated (p < 0.001) with poor overall survival in patients with EGFRM NSCLC receiving gefitinib (n = 100). In conclusion, LDOC1 may regulate the efficacy of first-generation EGFR-TKIs by participating in the CMI of EGFR. Accordingly, LDOC1 may function as a prognostic biomarker for EGFRM NSCLC.

Phosphorylation of AGO2 by TBK1 Promotes the Formation of Oncogenic miRISC in NSCLC.

Non-small-cell lung cancer (NSCLC) is a highly lethal tumor that often develops resistance to targeted therapy. It is shown that Tank-binding kinase 1 (TBK1) phosphorylates AGO2 at S417 (pS417-AGO2), which promotes NSCLC progression by increasing the formation of microRNA-induced silencing complex (miRISC). High levels of pS417-AGO2 in clinical NSCLC specimens are positively associated with poor prognosis. Interestingly, the treatment with EGFR inhibitor Gefitinib can significantly induce pS417-AGO2, thereby increasing the formation and activity of oncogenic miRISC, which may contribute to NSCLC resistance to Gefitinib. Based on these, two therapeutic strategies is developed. One is jointly to antagonize multiple oncogenic miRNAs highly expressed in NSCLC and use TBK1 inhibitor Amlexanox reducing the formation of oncogenic miRISC. Another approach is to combine Gefitinib with Amlexanox to inhibit the progression of Gefitinib-resistant NSCLC. This findings reveal a novel mechanism of oncogenic miRISC regulation by TBK1-mediated pS417-AGO2 and suggest potential therapeutic approaches for NSCLC.

A Phase II trial of alternating osimertinib and gefitinib therapy in advanced EGFR-T790M positive non-small cell lung cancer: OSCILLATE.

In this phase II, single arm trial (ACTRN12617000720314), we investigate if alternating osimertinib and gefitinib would delay the development of resistance to osimertinib in advanced, non-small cell lung cancer (NSCLC) with the epidermal growth factor receptor (EGFR) T790M mutation (n = 47) by modulating selective pressure on resistant clones. The primary endpoint is progression free-survival (PFS) rate at 12 months, and secondary endpoints include: feasibility of alternating therapy, overall response rate (ORR), overall survival (OS), and safety. The 12-month PFS rate is 38% (95% CI 27.5-55), not meeting the pre-specified primary endpoint. Serial circulating tumor DNA (ctDNA) analysis reveals decrease and clearance of the original activating EGFR and EGFR-T790M mutations which are prognostic of clinical outcomes. In 73% of participants, loss of T790M ctDNA is observed at progression and no participants have evidence of the EGFR C797S resistance mutation following the alternating regimen. These findings highlight the challenges of treatment strategies designed to modulate clonal evolution and the clinical importance of resistance mechanisms beyond suppression of selected genetic mutations in driving therapeutic escape to highly potent targeted therapies.