CD44s and CD44v8-10 isoforms confer acquired resistance to osimertinib by activating the ErbB3/STAT3 signaling pathway.

AIMS: Although epidermal growth factor receptor (EGFR)-mutant lung cancers respond well to osimertinib, acquired resistance to osimertinib eventually develops through EGFR-dependent and EGFR-independent resistance mechanisms. CD44 splicing variants are widely expressed in lung cancer tissues. However, it remains unclear whether specific splicing variants are involved in acquired resistance to osimertinib. MAIN METHODS: The real-time PCR was performed to measure the expression levels of total CD44 and specific CD44 splicing variants (CD44s or CD44v). Gene knockdown and restoration were performed to investigate the effects of CD44 splicing variants on osimertinib sensitivity. Activation of the signaling pathway was evaluated using receptor-tyrosine-kinase phosphorylation membrane arrays, co-immunoprecipitation, and western blotting. KEY FINDINGS: Clinical analysis demonstrated that the expression level of total CD44 increased in primary cancer cells from lung adenocarcinomas patients after the development of acquired resistance to osimertinib. Furthermore, osimertinib-resistant cells showed elevated levels of either the CD44s variant or CD44v variants. Manipulations of CD44s or CD44v8-10 were performed to investigate their effects on treatment sensitivity to osimertinib. Knockdown of CD44 increased osimertinib-induced cell death in osimertinib-resistant cells. However, restoration of CD44s or CD44v8-10 in CD44-knockdown H1975/AZD-sgCD44 cells induced osimertinib resistance. Mechanically, we showed that ErbB3 interacted with CD44 and was transactivated by CD44, that consequently triggered activation of the ErbB3/STAT3 signaling pathway and led to CD44s- or CD44v8-10-mediated osimertinib resistance. SIGNIFICANCE: CD44 is a co-receptor for ErbB3 and triggers activation of the ErbB3 signaling axis, leading to acquired resistance to osimertinib. CD44/ErbB3 signaling may represent a therapeutic target for overcoming osimertinib resistance.

Effects of Early Short-Course Corticosteroids on Immune-Related Adverse Events in Non-Small Cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors.

INTRODUCTION: In real-world practice, most non-small cell lung cancer (NSCLC) patients receiving combined immunochemotherapy are exposed to short-course corticosteroids following immune checkpoint inhibitor (ICI) infusion to prevent chemotherapy-related adverse events. However, whether this early short-course corticosteroid use prevents immune-related adverse events (irAEs) remains unknown. METHODS: Between January 1st, 2015, and December 31st, 2020, NSCLC patients who received at least one cycle of ICI with or without chemotherapy were enrolled. Early short-course corticosteroids were defined as corticosteroids administered following ICI injection and before chemotherapy on the same day and no longer than 3 days afterward. The patients were categorized as either "corticosteroid group" or "non-corticosteroid group" depending on their exposure to early short-course corticosteroid. The frequencies of irAEs requiring systemic corticosteroid use and irAEs leading to ICI discontinuation were compared between the two groups, and exploratory survival analyses were performed. RESULTS: Among 252 eligible patients, 137 patients were categorized as "corticosteroid group" and 115 patients as "non-corticosteroid group." The corticosteroid group enriched patients in the first-line setting (n = 75, 54.7%), compared to the non-corticosteroid group (n = 28, 24.3%). Thirty patients (21.9%) in the corticosteroid group and 35 patients (30.4%) in the non-corticosteroid group developed irAEs requiring systemic corticosteroid use (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.35-1.18; p = 0.15). Eight patients (5.8%) in the corticosteroid group, as compared with 18 patients (15.7%) in the non-corticosteroid group, permanently discontinued ICI due to irAEs (OR, 0.34; 95% CI, 0.12-0.85; p = 0.013). CONCLUSION: Early short-course corticosteroids following each ICI injection may reduce the rate of irAEs that lead to ICIs discontinuation, warranting further investigation of its prophylactic use to mitigate clinically significant irAEs.

miR-204 suppresses cancer stemness and enhances osimertinib sensitivity in non-small cell lung cancer by targeting CD44.

Osimertinib is an effective treatment option for patients with advanced non-small cell lung cancer (NSCLC) with EGFR activation or T790M resistance mutations; however, acquired resistance to osimertinib can still develop. This study explored novel miRNA-mRNA regulatory mechanisms that contribute to osimertinib resistance in lung cancer. We found that miR-204 expression in osimertinib-resistant lung cancer cells was markedly reduced compared to that in osimertinib-sensitive parental cells. miR-204 expression levels in cancer cells isolated from treatment-naive pleural effusions were significantly higher than those in cells with acquired resistance to osimertinib. miR-204 enhanced the sensitivity of lung cancer cells to osimertinib and suppressed spheroid formation, migration, and invasion of lung cancer cells. Increased miR-204 expression in osimertinib-resistant cells reversed resistance to osimertinib and enhanced osimertinib-induced apoptosis by upregulating BIM expression levels and activating caspases. Restoration of CD44 (the direct downstream target gene of miR-204) expression reversed the effects of miR-204 on osimertinib sensitivity, recovered cancer stem cell and mesenchymal markers, and suppressed E-cadherin expression. The study demonstrates that miR-204 reduced cancer stemness and epithelial-to-mesenchymal transition, thus overcoming osimertinib resistance in lung cancer by inhibiting the CD44 signaling pathway.

Tissue or liquid rebiopsy? A prospective study for simultaneous tissue and liquid NGS after first-line EGFR inhibitor resistance in lung cancer.

INTRODUCTION: According to current International Association for the Study of Lung Cancer guideline, physicians may first use plasma cell-free DNA (cfDNA) methods to identify epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-resistant mechanisms (liquid rebiopsy) for lung cancer. Tissue rebiopsy is recommended if the plasma result is negative. However, this approach has not been evaluated prospectively using next-generation sequencing (NGS). METHODS: We prospectively enrolled patients with lung cancer with first-line EGFR-TKI resistance who underwent tissue rebiopsy. The rebiopsied tissues and cfDNA were sequenced using targeted NGS, ACTDrug®+, and ACTMonitor®Lung simultaneously. The clinicopathological characteristics and treatment outcomes were analyzed. RESULTS: Totally, 86 patients were enrolled. Twenty-six (30%) underwent tissue biopsy but the specimens were inadequate for NGS. Among the 60 patients with paired tissue and liquid rebiopsies, two-thirds (40/60) may still be targetable. T790M mutations were found in 29, including 14 (48%) only from tissue and 5 (17%) only from cfDNA. Twenty-four of them were treated with osimertinib, and progression-free survival was longer in patients without detectable T790M in cfDNA than in patients with detectable T790M in cfDNA (p = 0.02). For the 31 T790M-negative patients, there were six with mesenchymal-epithelial transition factor (MET) amplifications, four with ERBB2 amplifications, and one with CCDC6-RET fusion. One with MET amplification and one with ERBB2 amplification responded to subsequent MET and ERBB2 targeting agents respectively. CONCLUSIONS: NGS after EGFR-TKI resistance may detect targetable drivers besides T790M. To do either liquid or tissue NGS only could miss patients with T790M. To do tissue and liquid NGS in parallel after EGFR-TKI resistance may find more patients with targetable cancers.

LncRNA SLCO4A1-AS1 suppresses lung cancer progression by sequestering the TOX4-NTSR1 signaling axis.

BACKGROUND: Metastasis is a multistep process involving the migration and invasion of cancer cells and is a hallmark of cancer malignancy. Long non-coding RNAs (lncRNAs) play critical roles in the regulation of metastasis. This study aims to elucidate the role of the lncRNA solute carrier organic anion transporter family member 4A1-antisense 1 (SLCO4A1-AS1) in metastasis and its underlying regulatory mechanisms. METHODS: A comprehensive analysis of the Gene Expression Omnibus (GEO) database were used to identify metastasis-associated lncRNAs. Transwell migration and invasion assays, and a tail vein-injection mouse model were used to assess the migration and invasion of cancer cells in vitro and in vivo, respectively. High-throughput screening methods, including MASS Spectrometry and RNA sequencing (RNA-seq), were used to identify the downstream targets of SLCO4A1-AS1. Reverse transcription quantitative polymerase chain reaction (RT-qPCR), western blotting, RNA pull-down, RNA immunoprecipitation (RIP), fluorescence in situ hybridization (FISH), and chromatin immunoprecipitation (ChIp) assays were conducted to identify and validate the underlying regulatory mechanisms of SLCO4A1-AS1. RESULTS: SLCO4A1-AS1 reduced cancer cell migration and invasion by disrupting cytoskeleton filaments, and was associated with longer overall survival in patients with lung adenocarcinoma. SLCO4A1-AS1 directly interacted with the DNA-binding protein, TOX High Mobility Group Box Family Member 4 (TOX4), to inhibit TOX4-induced migration and invasion. Furthermore, RNA-seq revealed that neurotensin receptor 1 (NTSR1) is a novel and convergent downstream target of SLCO4A1-AS1 and TOX4. Mechanistically, SLCO4A1-AS1 functions as a decoy of TOX4 by interrupting its interaction with the NTSR1 promoter and preventing NTSR1 transcription. Functionally, NTSR1 promotes cancer cell migration and invasion through cytoskeletal remodeling, and knockdown of NTSR1 significantly inhibits TOX4-induced migration and invasion. CONCLUSION: These findings demonstrated that SLCO4A1-AS1 antagonizes TOX4/NTSR1 signaling, underscoring its pivotal role in lung cancer cell migration and invasion. These findings hold promise for the development of novel therapeutic strategies targeting the SLCO4A1-AS1/TOX4/NTSR1 axis as a potential avenue for effective therapeutic intervention in lung cancer.

Upfront liquid next-generation sequencing in treatment-naïve advanced non-small cell lung cancer patients: A prospective randomised study in the Taiwanese health system.

BACKGROUND: Next-generation sequencing (NGS) of plasma cell-free DNA identifies driver mutations in advanced non-small cell lung cancer (NSCLC) and may complement routine molecular evaluation. The utility of liquid NGS at the start of tumour workup is undetermined. METHODS: This is a randomised study of patients with suspected advanced NSCLC. All patients received blood liquid NGS testing at their first clinic visit and underwent standard histological diagnosis and tissue genotyping, encompassing polymerase chain reaction based methods for EGFR mutation, immunohistochemical (IHC) staining for ALK fusion and BRAF V600E mutation, and an IHC screening followed by confirmation using fluorescence in situ hybridization confirmation for ROS1 fusion. They were then randomly assigned to receive NGS results either after tissue genotyping (Group A) or as soon as possible after histological diagnosis of advanced NSCLC (Group B). The study measured time to start of systemic treatment as the primary endpoint and secondary endpoints included biomarker discovery rate, objective response rate (ORR), and progression-free survival (PFS). RESULTS: This study enroled 180 patients with suspected advanced NSCLC, randomised into two groups. 63 patients in Group A and 59 in Group B with advanced NSCLC were confirmed as advanced NSCLC and analysed. Most had adenocarcinoma (Group A: 77.8%, Group B: 79.7%). The prevalence of EGFR mutations in the two groups was similar (Group A: 57.1%; Group B: 56.6%). Other driver alterations were rare. The median time to treatment was shorter in Group B (20 days) than in Group A (28 days). ORR and PFS did not differ between groups significantly. Liquid NGS had high concordance with tissue testing and identified driver mutations in 42.6% (20/47) of tissue-negative cases. CONCLUSION: Performing liquid NGS at the initial clinic visit for suspected advanced NSCLC identifies more patients suitable for targeted therapies and shortens time to the start of treatment.

MiR-503 pleiotropically regulates epithelial-mesenchymal transition and targets PTK7 to control lung cancer metastasis.

OBJECTIVE: In lung cancer patients, most deaths are caused by the distant dissemination of cancer cells. Epithelial-mesenchymal transition (EMT) and collective cell migration are distinct and important mechanisms involved in cancer invasion and metastasis. Additionally, microRNA dysregulation contributes significantly to cancer progression. In this study, we aimed to explore the function of miR-503 in cancer metastasis. METHODS: Molecular manipulations (silencing or overexpression) were performed to investigate the biological functions of miR-503 including migration and invasion. Reorganization of cytoskeleton was assessed using immunofluorescence and the relationship between miR-503 and downstream protein tyrosine kinase 7 (PTK7) was assessed using quantitative real-time PCR, immunoblotting, and reporter assays. The tail vein metastatic animal experiments were performed. RESULTS: Herein, we demonstrated that the downregulation of miR-503 confers an invasive phenotype in lung cancer cells and provided in vivo evidence that miR-503 significantly inhibits metastasis. We found that miR-503 inversely regulates EMT, identified PTK7 as a novel miR-503 target, and showed the functional effects of miR-503 on cell migration and invasion were restored upon reconstitution of PTK7 expression. As PTK7 is a Wnt/planar cell polarity protein crucial for collective cell movement, these results implicated miR-503 in both EMT and collective migration. However, the expression of PTK7 did not influence EMT induction, suggesting that miR-503 regulates EMT through mechanisms other than PTK7 inhibition. Furthermore, we discovered that PTK7 mechanistically activates focal adhesion kinase (FAK) and paxillin, thereby controlling the reorganization of the cortical actin cytoskeleton. CONCLUSION: Collectively, miR-503 is capable of governing EMT and PTK7/FAK signaling independently to control the invasion and dissemination of lung cancer cells, indicating that miR-503 represents a pleiotropic regulator of cancer metastasis and hence a potential therapeutic target for lung cancer.

Different treatment efficacies and T790M acquisition of EGFR-TKIs on NSCLC patients with variable Del-19 subtypes of EGFR.

EGFR exon 19 deletion (Del-19) comprises multiple advanced NSCLC subtypes. EGFR-tyrosine kinase inhibitor (TKI) efficacy and T790M acquisition in various Del-19 subtypes is unknown. We prospectively collected tissue samples from patients harboring NSCLC with Del-19 between 2006 and 2020. We evaluated EGFR-TKI treatment effectiveness among the different Del-19 subtypes. We collected 1391 NSCLC samples from 892 patients with Del-19, and the most common subtype was del E746-A750 (67.5%). 741 patients had taken first- or second-generation EGFR-TKIs. There were no significant differences in response rates between patients with different Del-19 subtypes (P = .630). Patients with indel E746 had the longest median PFS (14.6 months), but those with non-LRE deletions had the shortest PFS (8.9 months; P = .002). For OS analysis, patients with indel E746 also had the longest OS (34.1 months), but those with non-LRE deletions had the shortest OS (21.1 months; P = .046). Patients with different Del-19 subtypes showed no significant differences in the T790M acquisition rates (P = .443). Among the 151 patients with acquired T790M who received third-generation EGFR-TKIs, the Del-19 subtype was not associated with different RR and PFS. In vitro cellular viability and activation of the EGFR pathway analysis were consistent with the clinical findings. In conclusion, compared with del E746-A750, indel E746 was associated with longer PFS and OS, but the non-LRE subtype was correlated with shorter survival prognosis. There were no significant differences in the acquired T790M rate and treatment effectiveness of subsequent third-generation EGFR-TKIs between various Del-19 subgroups.

Survival outcomes and prognostic factors of lung cancer patients with the MET exon 14 skipping mutation: A single-center real-world study.

Introduction: The MET exon 14 skipping (METex14) mutation is an important oncogenic driver in lung cancer. We performed a retrospective analysis of clinical data from lung cancer patients with the METex14 mutation to analyze their survival outcomes and associated prognostic factors. Methods: A one-step reverse transcription-polymerase chain reaction to examine the presence of the METex14 mutation was performed using RNA samples from 1374 lung cancer patients with no detected EGFR and ALK mutations. Pathological features and immunohistochemistry (IHC) results for c-MET were analyzed in patients with METex14-positive tumors. Results: METex14 was identified in 69 patients with lung cancer, including 53 adenocarcinoma (ADC) and 16 non-ADC patients. In comparison with patients without the METex14 mutation, lung cancer patients harboring the METex14 mutation were generally elderly individuals, never-smokers, and had poor performance scores. A higher frequency of METex14 mutations was detected in pulmonary sarcomatoid carcinoma (PSC) patients (24.3%, n = 9/37). However, stage IV PSC patients with or without the METex14 mutations showed similarly poor overall survival (OS) (p = 0.429). For all 36 METex14-positive lung ADCs, multivariate analysis showed several poor prognostic factors, including strong c-MET IHC staining (p = 0.006), initial brain metastasis (p = 0.005), and administration of only supportive care (p < 0.001). After excluding seven patients who received only supportive care, we further analyzed 29 stage IV lung ADC patients with METex14 mutations who received anti-cancer treatment. Multivariate analysis showed that pemetrexed treatment (p = 0.003), lung radiotherapy (p = 0.020), initial brain metastasis (p = 0.005), and strong c-MET IHC staining (p = 0.012) were independent prognostic factors for OS in these patients. Conclusions: A higher frequency of METex14 mutations was detected in PSC patients. Stage IV PSC patients with or without the METex14 mutations had similarly poor overall survival. Pemetrexed-based chemotherapy, strong c-MET ICH staining, initial brain metastasis, and lung radiotherapy, may help predict survival outcomes in patients with advanced lung ADCs harboring the METex14 mutation.

Multidisciplinary management of patients with non-small cell lung cancer with leptomeningeal metastasis in the tyrosine kinase inhibitor era.

OBJECTIVE: Leptomeningeal metastasis (LM) is a challenging scenario in non-small cell lung cancer (NSCLC). Considering that outcomes of treatment modalities stratified by LM chronological patterns related to brain metastasis (BM) are lacking, the aim of this study was to evaluate outcomes and explore prognostic factors. METHODS: The authors retrospectively collected data of patients with NSCLC undergoing Ommaya reservoir implantation, ventriculoperitoneal shunt implantation, or lumboperitoneal shunt implantation. Based on radiographic findings and time from diagnosis of NSCLC to LM, the authors divided them into subtypes of LM as follows: LM without BM; LM concurrent with BM; or LM after BM. The Kaplan-Meier method was applied to analyze overall survival (OS) and multivariate Cox regression for prognostic factors. RESULTS: Sixty-one patients with LM were included, with a median OS of 8.1 (range 0.2-70.0) months. Forty-three (70.5%) patients had EGFR-mutant disease. Forty-two (68.9%) patients had 19-del or L858R mutation, and one (1.6%) patient had G719A mutation. Fifty-seven (93.4%) patients had hydrocephalus. Twenty-one (34.4%) patients received whole-brain radiotherapy before LM diagnosis, 3 (4.9%) patients underwent operation for BMs before LM diagnosis, and 42 (68.9%) patients received EGFR tyrosine kinase inhibitor (TKI) therapy before LM diagnosis. Eleven patients were treated with chemotherapy, 10 patients were treated with TKIs, and 32 patients were treated with chemotherapy combined with TKIs before LM diagnosis. Patients with LM after BM had lower Karnofsky Performance Status (KPS) scores (KPS score 50) than did those with LM without BM (KPS score 80) or LM concurrent with BM (KPS score 70; p = 0.003). More patients with LM after BM received intrathecal methotrexate than in the other subgroups (p < 0.001). The median OS was significantly shorter in the LM after BM than in the concurrent LM and BM and the LM without BM subgroups (5.4 vs 5.5 vs 11.6 months; p = 0.019). Cox regression revealed that a KPS score ≥ 70 (HR 0.51; p = 0.027) and shunt implantation (HR 0.41; p = 0.032) were favorable prognostic factors. CONCLUSIONS: Patients with NSCLC who had LM without BM had better survival outcomes (11.6 months) compared with those who had LM after BM or concurrent LM and BM. Aggressive shunt implantation may be favored for LM.

Clinical outcomes of Atezolizumab Therapy for Previously-Treated Advanced-Stage Non-Small Cell Lung Cancer: A Real-World Study in Taiwan.

Immune checkpoint inhibitors (ICIs) are the standard treatment for non-small-cell lung cancer (NSCLC). We assessed the clinical prognostic factors in NSCLC patients receiving atezolizumab as a second- or later-line (2L+) treatment. Data were retrospectively collected for NSCLC patients treated with atezolizumab from July 2017 to June 2019 at six medical centers in Taiwan. Clinical characteristics, treatment course and responses of patients were recorded. A total of 128 NSCLC patients received 2L+ atezolizumab, and the outcomes included a response rate of 10.2%, median progression-free survival (mPFS) of 3.5 months, and median overall survival (mOS) of 10.7 months. Eleven patients who had received osimertinib treatment before atezolizumab had a shorter mPFS (2.3 versus 3.5 months; p = 0.002) and mOS (4.8 versus 11.2 months; p < 0.001) than those without prior osimertinib treatment. Even for the subgroup of patients with EGFR-mutant non-squamous NSCLC, prior osimertinib was still associated with shorter PFS (2.3 versus 4.1 months; p = 0.006) and OS (4.8 versus 11.7 months; p < 0.001). Multivariate analysis revealed that prior osimertinib treatment correlated with not only shorter PFS (hazard ratio [HR]: 2.94; 95% confidence interval [CI], 1.34-6.47; p = 0.007) but also shorter OS (HR, 3.55; 95% CI, 1.57-8.03; p = 0.002). Patients with prior ICIs treatment (HR, 3.18; p = 0.002) or poor performance status (HR, 2.70; p = 0.001) had shorter OS. In conclusion, osimertinib treatment before atezolizumab therapy was associated with a shorter PFS and a poor prognosis in NSCLC patients in real-world settings. Further studies with larger sample sizes are needed to validate these observations.

Prognostic significance of dynamin-related protein 1 expression in advanced lung adenocarcinoma.

BACKGROUND: Dynamin-related protein 1 (DRP1) is a key regulator of mitochondrial fission and is activated by phosphorylation at serine 616. We previously demonstrated that DRP1 activation is regulated by epidermal growth factor receptor (EGFR) signaling and multiple kinases in lung adenocarcinoma, and is significantly associated with an increased risk of postoperative recurrence in early stage lung adenocarcinoma. However, it is unclear whether DRP1 activation is associated with worse prognosis in patients with advanced lung adenocarcinoma. This study is aimed to examine whether P(S616)-DRP1 expression is significantly related to the survival of patients with advanced lung adenocarcinoma. MATERIALS AND METHODS: Biopsy samples were obtained from patients with stage IV lung adenocarcinoma. The activation status of DRP1 in cancer cells was quantified based on the immunohistochemical stain of phosphorylated DRP1 at serine 616 [P(S616)-DRP1]. Results of EGFR, ALK, ROS1, and KRAS mutations were retrieved from the medical records. The staining intensity and the histological scores (H-scores) of P(S616)-DRP1 were analyzed for association with progression-free survival (PFS) under first-line tyrosine-kinase inhibitors (TKIs) and with overall survival (OS). RESULTS: Overall, 123 patients with stage IV lung adenocarcinoma constituted the study population, and 90 (73.2%) patients received TKIs as the first-line treatments. The median P(S616)-DRP1H-score was used to dichotomize the study population into the high (n = 61) and low (n = 62) DRP1 activation groups. DRP1 was significantly less phosphorylated in lung adenocarcinoma with EGFR, ALK, ROS1, and KRAS mutations. Importantly, in patients who received first-line TKIs, DRP1 phosphorylation was not significantly correlated with PFS and OS. Multivariate Cox proportional hazard models showed that high DRP1 activation in cancer cells was not significantly associated with worse OS in the study population (adjusted hazard ratio: 1.402, 95% confidence interval: 0.865-2.271, p = 0.170). Similar results were obtained in the analysis based on the intensities of P(S616)-DRP1 in cancer cells. CONCLUSIONS: Our data demonstrate that DRP1 phosphorylation is not related to the prognosis of patients with advanced lung adenocarcinoma.

Prognostic Characteristics and Immunotherapy Response of Patients With Nonsquamous NSCLC With Kras Mutation in East Asian Populations: A Single-Center Cohort Study in Taiwan.

INTRODUCTION: Kras mutation is the most common driver oncogene present in patients with NSCLC. Recently, the precision medicine for patients with Kras-mutated NSCLC has been under investigation, but the best treatment is still unknown. This study aimed to analyze the clinical characteristics, immune checkpoint inhibitor (ICI) response, and prognostic factors of patients with NSCLC with different Kras mutation subtypes. METHODS: From 2005 to 2018, we collected nonsquamous NSCLC tissue samples for Kras mutation analysis using direct Sanger sequencing or MassARRAY genotyping (Agena Bioscience, San Diego, CA) at the National Taiwan University Hospital. Clinical characteristics, ICI treatment effectiveness, time-to-tumor recurrence (TTR), and overall survival (OS) were analyzed using multivariate Cox models, to estimate adjusted hazard ratios (HRs). RESULTS: Among 5278 patients with nonsquamous NSCLC, 246 (4.7%) had Kras mutations. The major Kras mutation subtypes were G12C (32.9%), G12D (23.7%), and G12V (18.9%). Patients with Kras-G12C had a higher proportion of male individuals (p = 0.018) and smokers (p < 0.001). Among the 25 patients treated with ICIs, patients with Kras-G12C had a higher response rate (53.8% versus 8.3%, p = 0.030) and longer progression-free survival (4.8 mo versus 2.1 mo, p = 0.028) than those with Kras-non-G12C. For the 85 patients with early-stage NSCLC, those with G12C had shorter TTR (22.8 mo) than those with Kras-non-G12C (97.7 mo, p = 0.004). For the 143 patients with advanced-stage NSCLC, there was a significant difference in OS between patients with Kras-G12C and Kras-non-G12C (7.7 mo versus 6.0 mo, p = 0.018) and patients with Kras-G12V had the shortest OS (5.2 mo). Multivariate analysis revealed association of shorter OS with Kras-G12V (HR = 2.47, p = 0.002), stage IV disease status (HR = 2.69, p = 0.008), and NSCLC-not otherwise specified histology (HR = 3.12, p = 0.002). CONCLUSIONS: Kras-G12C was associated with favorable ICI treatment effectiveness in patients with NSCLC. Kras-G12C mutation was associated with shorter TTR in patients with early-stage NSCLC, and Kras-G12V mutation was associated with shorter OS in patients with advanced-stage NSCLC when comparing with Kras-G12C.

Multi-kinase framework promotes proliferation and invasion of lung adenocarcinoma through activation of dynamin-related protein 1.

Recent studies revealed the role of dynamin-related protein 1 (DRP1), encoded by the DNM1L gene, in regulating the growth of cancer cells of various origins. However, the regulation, function, and clinical significance of DRP1 remain undetermined in lung adenocarcinoma. Our study shows that the expression and activation of DRP1 are significantly correlated with proliferation and disease extent, as well as an increased risk of postoperative recurrence in stage I to stage IIIA lung adenocarcinoma. Loss of DRP1 in lung adenocarcinoma cell lines leads to an altered mitochondrial morphology, fewer copies of mitochondrial DNA, decreased respiratory complexes, and impaired oxidative phosphorylation. Additionally, the proliferation and invasion are both suppressed in DRP1-depleted lung adenocarcinoma cell lines. Our data further revealed that DRP1 activation through serine 616 phosphorylation is regulated by ERK/AKT and CDK2 in lung adenocarcinoma cell lines. Collectively, we propose the multikinase framework in activating DRP1 in lung adenocarcinoma to promote the malignant properties. Biomarkers related to mitochondrial reprogramming, such as DRP1, can be used to evaluate the risk of postoperative recurrence in early-stage lung adenocarcinoma.

Cone-Beam Computed Tomography-Derived Augmented Fluoroscopy Improves the Diagnostic Yield of Endobronchial Ultrasound-Guided Transbronchial Biopsy for Peripheral Pulmonary Lesions.

BACKGROUND: Endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB) is used for the diagnosis of peripheral pulmonary lesions (PPLs), but the diagnostic yield is not adequate. Cone-beam computed tomography-derived augmented fluoroscopy (CBCT-AF) can be utilized to assess the location of PPLs and biopsy devices, and has the potential to improve the diagnostic accuracy of bronchoscopic techniques. The purpose of this study was to verify the contribution of CBCT-AF to EBUS-TBB. METHODS: Patients who underwent EBUS-TBB for diagnosis of PPLs were enrolled. The navigation success rate and diagnostic yield were used to evaluate the effectiveness of CBCT-AF in EBUS-TBB. RESULTS: In this study, 236 patients who underwent EBUS-TBB for PPL diagnosis were enrolled. One hundred fifteen patients were in CBCT-AF group and 121 were in non-AF group. The navigation success rate was significantly higher in the CBCT-AF group (96.5% vs. 86.8%, p = 0.006). The diagnostic yield was even better in the CBCT-AF group when the target lesion was small in size (68.8% vs. 0%, p = 0.026 for lesions ≤10 mm and 77.5% vs. 46.4%, p = 0.016 for lesions 10-20 mm, respectively). The diagnostic yield of the two study groups became similar when the procedures with a failure of navigation were excluded. The procedure-related complication rate was similar between the two study groups. CONCLUSION: CBCT-AF is safe, and effectively enhances the navigation success rate, thereby increasing the diagnostic yield of EBUS-TBB for PPLs.

miR-146b-5p Enhances the Sensitivity of NSCLC to EGFR Tyrosine Kinase Inhibitors by Regulating the IRAK1/NF-κB Pathway.

Although patients with non-small cell lung cancer harboring activating mutations in the epidermal growth factor receptor (EGFR) show good clinical response to EGFR tyrosine kinase inhibitors (TKIs), patients eventually develop acquired resistance. Previous studies have shown that several microRNAs (miRNAs) are involved in EGFR TKI resistance. Here, we aimed to investigate whether miR-146b-5p sensitizes the EGFR TKI-resistant lung cancer cells. Clinical analysis showed that miR-146b-5p expression in lung cancer cells isolated from pleural effusions of treatment-naive patients was significantly higher than that after acquiring resistance to EGFR TKI treatment. Ectopic expression of miR-146b-5p in EGFR TKI-resistant cells enhanced EGFR TKI-induced apoptosis. The same results were observed in EGFR-dependent and -independent osimertinib-resistant primary cancer cells (PE3479 and PE2988). Mechanically, miR-146b-5p suppressed nuclear factor κB (NF-κB) activity and NF-κB-related IL-6 and IL-8 production by targeting IRAK1. A negative correlation was observed between miR-146b-5p and IRAK1 in clinical specimens. In rescue experiments, restoration of IRAK1 expression reversed the effects of miR-146b-5p on EGFR TKI sensitivity and recovered NF-κB-regulated IL-6 and IL-8 production. In conclusion, miR-146b-5p/IRAK1/NF-κB signaling is important in promoting EGFR TKI resistance, and miR-146b-5p may be a useful tool for overcoming EGFR TKI resistance.

An Observational Study of Acquired EGFR T790M-Dependent Resistance to EGFR-TKI Treatment in Lung Adenocarcinoma Patients in Taiwan.

In Taiwan, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs), gefitinib, erlotinib, and afatinib are served as first-line therapy for non-small lung cell cancer (NSCLC) patients with EGFR sensitizing mutations. However, the majority of patients who initially respond to EGFR-TKIs, progress through acquiring EGFR T790M mutations (T790M), which is the most common resistant mechanism. Patients with T790M gain the opportunity of subsequent treatment with third-generation EGFR-TKI, osimertinib. This study aimed to evaluate the association between prior EGFR-TKI therapy and incidence of acquired T790M resistance in lung adenocarcinoma patients who have progressed on first/second-generation EGFR-TKI therapy. This retrospective study included lung adenocarcinoma patients who had a radiographically-confirmed progressive disease under EGFR-TKI treatment and had re-biopsy samples for T790M testing from seven medical centers in Taiwan from June 2013 to December 2018. Patients harboring de novo T790M or using more than one EGFR-TKI were excluded. Of the 407 patients enrolled, the overall T790M acquisition rate was 52.8%. The patients treated with gefitinib, erlotinib or afatinib had a statistically significant difference in the T790M rates (59.9, 45.5, and 52.7%, respectively; p = 0.037) after disease progression. Patients with common baseline EGFR mutations (Del-19 and L858R) (p = 0.005) and longer treatment duration with EGFR-TKIs (p < 0.001) had higher chances of T790M acquisition. Multivariate logistic regression analysis further showed that patients with common baseline EGFR mutations, gefitinib (compared to erlotinib) administration, and longer treatment duration with EGFR-TKIs had higher T790M incidence. There was no significant difference in the incidence of acquired T790M between different re-biopsy tissue samples or complications. In conclusion, this study showed that patients who progressed from gefitinib treatment, bearing common EGFR mutations, and with longer EGFR-TKI treatment duration had increased incidence of T790M acquisition and, therefore, were suitable for subsequent osimertinib treatment.

The effectiveness of afatinib in patients with lung adenocarcinoma harboring complex epidermal growth factor receptor mutation.

BACKGROUND AND AIMS: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) are effective against classical EGFR mutations in lung cancer. However, their effectiveness and the prognosis of lung cancer patients with complex EGFR mutations are not well delineated. Therefore, we aimed to investigate the treatment effectiveness of different EGFR TKIs in patients with complex EGFR mutations. PATIENTS AND METHODS: From 2005 to 2020, we collected lung adenocarcinoma tissue samples for EGFR mutation analysis using direct Sanger sequencing. Patients with EGFR mutations treated with EGFR TKIs as first-line treatment were enrolled. Clinical characteristics, EGFR mutation status, treatment response, progression-free survival (PFS), and overall survival (OS) were analyzed. RESULTS: Among 2675 patients with EGFR mutations, 239 (8.9%) had complex EGFR mutations, of whom 125 received EGFR TKI treatment as first-line treatment. Multivariate analysis revealed that afatinib was a more favorable factor for PFS than gefitinib [hazard ratio (HR), 2.01; 95% confidence interval (CI), 1.11-3.62] and erlotinib (HR, 2.61; 95% CI, 1.31-5.22), especially in patients with uncommon mutation patterns. Afatinib treatment as first-line treatment was also associated with longer OS compared with erlotinib (HR, 2.48; 95% CI, 1.20-5.12). Classical mutation pattern was associated with longer PFS (p = 0.001) and OS (p = 0.020). Secondary T790M was detected in 22 of 52 (42.3%) patients who had re-biopsied tissue samples after acquiring resistance to EGFR TKIs. There was no significant difference in secondary T790M formation after acquired resistance to the three EGFR TKIs (p = 0.261). Furthermore, three (5.8%) patients had small-cell lung cancer transformation. CONCLUSION: Afatinib is an effective first-line treatment for patients with lung adenocarcinoma harboring complex EGFR mutations, especially those with uncommon mutation patterns.

Complex EGFR mutations with secondary T790M mutation confer shorter osimertinib progression-free survival and overall survival in advanced non-small cell lung cancer.

OBJECTIVES: Osimertinib is active against epidermal growth factor receptor (EGFR) T790M-mutated non-small cell lung cancer (NSCLC). However, its efficacy against complex EGFR mutations with T790M has not been evaluated. MATERIALS AND METHODS: In order to detect complex EGFR mutations, we consecutively sequenced cancer tissues by RNA reverse transcription polymerase chain reaction. Patients with advanced NSCLC with activating EGFR mutation and secondary T790M who received osimertinib were enrolled. Patients' clinicopathologic characteristics, prior treatment details, and osimertinib treatment outcomes were analyzed. RESULTS: Totally, 165 sequenced patients were analyzed. Eleven (7%) of them had complex EGFR mutations with T790M. The osimertinib response rate was 27%. They had a shorter progression-free survival (PFS) (median, 2.9 and 9.7 months, p < 0.001) and overall survival (OS) (median, 17.8 and 31.0 months, p = 0.01) than patients with a single EGFR mutation with T790M. After osimertinib failure, seven patients received rebiopsy with molecular analysis. Four lost the T790M, two transformed to small cell and one acquired C797S. Moreover, taking the median as the demarcation, patients received shorter prior EGFR tyrosine kinase inhibitor (TKI) treatment duration had a shorter osimertinib PFS (median, 7.3 and 13.8 months, p < 0.001) and OS (median, 21.5 and 36.7 months, p = 0.003). Multivariate Cox regression analysis confirmed complex EGFR mutations and prior EGFR TKI treatment duration were independent factors for osimertinib PFS and OS. CONCLUSIONS: Complex EGFR mutations and shorter prior EGFR TKI treatment duration may confer shorter osimertinib PFS and OS in advanced NSCLC with secondary T790M mutation.

MiR-200c-3p suppression is associated with development of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in EGFR mutant non-small cell lung cancer via a mediating epithelial-to-mesenchymal transition (EMT) process.

BACKGROUND: EGFR-mutant lung cancer inevitably develops resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). OBJECTIVE: To investigate the clinical relevance of microRNAs (miRNAs) in TKI therapy response and resistance. METHODS: We performed a miRNA PCR array analysis and used The Cancer Genome Atlas (TCGA) database to identify potential miRNAs related to EGFR TKIs resistance. We then correlated miRNA expression in 70 surgical and 50 malignant pleural effusion specimens with patient outcomes in those with non-small cell lung carcinoma. Molecular manipulation was performed in EGFR mutant lung cancer cells to assess the effect of miR-200c-3p on cell migratory ability and EGFR-TKI sensitivity. RESULTS: We identified miR-200c-3p and miR-203a-3p as potential EGFR TKI resistance regulators via their modulation of epithelial-to-mesenchymal transition (EMT). MiR-200c-3p and miR-203a-3p were down-regulated in EGFR TKI-resistant cell lines. Progression-free survival (PFS) with EGFR-TKI treatment of patients with high miR-200c-3p expression, but not miR-203a-3p, in the specimens was significantly longer than that of patients with low expression. MiR-200c-3p overexpression inhibited the EMT process in EGFR TKI resistance cell lines and promoted cell death. MiR-200c-3p silencing in EGFR TKI sensitive cell lines increased drug resistance. CONCLUSION: MiR-200c-3p plays a role in sensitivity to EGFR TKIs via modulating EMT process.