Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Resistance Research Articles

Hsa_circ_0005576 promotes osimertinib resistance through the miR-512-5p/IGF1R axis in lung adenocarcinoma cells.

Osimertinib is a third‐generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR‐TKI) for lung adenocarcinoma (LUAD) harboring activating mutations, but patients ultimately develop acquired resistance. Circular RNAs are involved in EGFR‐TKI resistance, while the role of hsa_circ_0005576 in the osimertinib resistance of LUAD remains unknown. In this study, we demonstrated that hsa_circ_0005576 could facilitate osimertinib‐resistant LUAD cells. Briefly, knockdown of hsa_circ_0005576 not only suppressed the proliferation and promoted the apoptosis of resistant LUAD cells, but also increased their sensitivity to osimertinib. Mechanistically, hsa_circ_0005576, serving as an miRNA sponge, could directly interact with miR‐512‐5p and subsequently upregulate the miR‐512‐5p‐targeted insulin‐like growth factor 1 receptor. Rescue assays indicated that miR‐512‐5p inhibition could reverse the effects of hsa_circ_0005576 knockdown in LUAD cells resistant to osimertinib. Overall, our study revealed that hsa_circ_0005576 regulates proliferation and apoptosis through miR‐512‐5p/IGF1R signaling, which contributes further to the resistance of LUAD cells to osimertinib. In addition, this study provides a novel insight into the mechanisms underlying osimertinib resistance of LUAD.

ELF3 Is a Target That Promotes Therapeutic Efficiency in EGFR Tyrosine Kinase Inhibitor-Resistant Non-Small Cell Lung Cancer Cells via Inhibiting PKCί.

(1) Background: Mutations in epidermal growth factor receptor (EGFR) proteins account for many non-small cell lung cancers (NSCLCs), and EGFR tyrosine kinase inhibitors (TKIs) are being used as targeted therapeutics. However, resistance to TKIs continues to increase owing to additional mutations in more than half of the patients receiving EGFR TKI therapy. In addition to targeting new mutations with next-generation therapeutics, it is necessary to find an alternative target to overcome the challenges associated with resistance. (2) Methods: To identify potential alternative targets in patients with NSCLC undergoing targeted therapy, putative targets were identified by transcriptome profiling and validated for their biological and therapeutic effects in vitro and in vivo. (3) Results: ELF3 was found to be differentially expressed in NSCLC, and ELF3 knockdown significantly increased cell death in K-Ras mutant as well as in EGFR L858R/T790M mutation harboring lung cancer cells. We also found that auranofin, an inhibitor of protein kinase C iota (PKCί), a protein upstream of ELF3, effectively induced cell death. (4) Conclusions: Our study suggests that blocking ELF3 is an effective way to induce cell death in NSCLC with K-Ras and EGFR T790M/L858R mutations and thus advocates the use of auranofin as an effective alternative drug to overcome EGFR TKI resistance.

Real-World Approach for Molecular Analysis of Acquired EGFR Tyrosine Kinase Inhibitor Resistance Mechanisms in NSCLC

IntroductionWith the approval of first-line osimertinib treatment in stage IV EGFR-mutated NSCLC, detection of resistance mechanisms will become increasingly important—and complex. Clear guidelines for analyses of these resistance mechanisms are currently lacking. Here, we provide our recommendations for optimal molecular diagnostics in the post-EGFR tyrosine kinase inhibitor (TKI) resistance setting. MethodsWe compared molecular workup strategies from three hospitals of 161 first- or second-generation EGFR TKI–treated cases and 159 osimertinib-treated cases. Laboratories used combinations of DNA next-generation sequencing (NGS), RNA NGS, in situ hybridization (ISH), and immunohistochemistry (IHC). ResultsResistance mechanisms were identified in 72 first-generation TKI cases (51%) and 85 osimertinib cases (57%). RNA NGS, when performed, revealed fusions or exon-skipping events in 4% of early TKI cases and 10% of osimertinib cases. Of the 30 MET and HER2 amplifications, 10 were exclusively detected by ISH or IHC, and not detected by DNA NGS, mostly owing to low tumor cell percentage (<30%) and possibly tumor heterogeneity. ConclusionsOur real-world data support a method for molecular diagnostics, consisting of a parallel combination of DNA NGS, RNA NGS, MET ISH, and either HER2 ISH or IHC. Combining RNA and DNA isolation into one step limits dropout rates. In case of financial or tissue limitations, a sequential approach is justifiable, in which RNA NGS is only performed in case no resistance mechanisms are identified. Yet, this is suboptimal as—although rare—multiple acquired resistance mechanisms may occur.

Drug resistance of targeted therapy for advanced non-small cell lung cancer harbored EGFR mutation: from mechanism analysis to clinical strategy.

Non-small cell lung cancer (NSCLC) accounts for about 85% in all cases of lung cancer. In recent years, molecular targeting drugs for NSCLC have been developed rapidly. The epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have changed the paradigm of cancer therapy from empirical cytotoxic chemotherapy to molecular-targeted cancer therapy. Currently, there are three generations of EGFR-TKIs, all of which have achieved good efficacy in clinical therapy. However, most patients developed drug resistance after 6-13months EGFR-TKIs treatment. Therefore, a comprehensive understanding of EGFR-TKIs resistance mechanisms is of vital importance for clinical management of NSCLC. Relevant data and information about the topic were obtained by searching PubMed (Medline), Web of Science and Google Scholar using the subject headings, such as "NSCLC", "EGFR-TKIs resistance", "EGFR mutations", "human epidermal growth factor receptor-2 (HER2/erbB-2)", "hepatocyte growth factor (HGF)", "vascular endothelial growth factor (VEGF)", "insulin-like growth factor 1 (IGF-1)", "epithelial-mesenchymal transition (EMT)", "phosphatase and tensin homolog (PTEN)", "RAS mutation", "BRAF mutation", "signal transducer and activator of transcription 3 (STAT3)", and "tumor microenvironment", etc. RESULTS: The mechanisms for EGFR-TKIs resistance include EGFR mutations, upregulation of HER2, HGF/c-MET, VEGF IGF1, EMT and STAT3 pathways, mutations of PTEN, RAS and BRAF genes, and activation of other by-pass pathways. These mechanisms are interconnected and can be potential targets for the treatment of NSCLC. In this review, we discuss the mechanisms of EGFR-TKIs drug resistance and the clinical strategies to overcome drug resistance from the perspective of EGFR-TKIs combined treatment.

PAR2 blockade reverses osimertinib resistance in non-small-cell lung cancer cells via attenuating ERK-mediated EMT and PD-L1 expression

Osimertinib, as the third-generation EGFR tyrosine kinase inhibitors (EGFR-TKIs), is a first-line molecularly targeted drug for non-small cell lung cancer (NSCLC). However, the emergence of therapeutic resistance to osimertinib markedly impairs its efficiency and efficacy, leading to the failure of clinical applications. Novel molecular targets and drugs are urgently needed for reversing osimertinib resistance in NSCLC. Protease-activated receptor 2 (PAR2) that belongs to a subfamily of G protein-coupled receptors can stimulate the transactivation of EGFR to regulate multiple cellular signalling, actively participating in tumour progression. This study firstly discovered that PAR2 expression was notably enhanced when NSCLC cells became resistant to osimertinib. A PAR2 inhibitor facilitated osimertinib to attenuate EGFR transactivation, ERK phosphorylation, EMT and PD-L1 expression which were associated to osimertinib resistance. The combination of the PAR2 inhibitor and osimertinib also notably blocked cell viability, migration, 3D sphere formation and in vivo tumour growth whereas osimertinib itself lost such inhibitory effects in osimertinib-resistant NSCLC cells. Importantly, this reversal effect of PAR2 blockade was uncovered to depend on ERK-mediated EMT and PD-L1, since inhibition of β-arrestin or ERK, which could be modulated by PAR2, sensitized osimertinib to prevent EMT, PD-L1 expression and consequently overcame osimertinib resistance. Thus, this study demonstrated that PAR2 antagonism could limit ERK-mediated EMT and immune checkpoints, consequently attenuating EGFR transactivation and reactivate osimertinib. It suggested that PAR2 may be a novel drug target for osimertinib resistance, and PAR2 inhibition may be a promising strategy candidate for reversing EGFR-TKI resistance in NSCLC.

Identification and validation of hub genes of synovial tissue for patients with osteoarthritis and rheumatoid arthritis

BackgroundOsteoarthritis (OA) and rheumatoid arthritis (RA) were two major joint diseases with similar clinical phenotypes. This study aimed to determine the mechanistic similarities and differences between OA and RA by integrated analysis of multiple gene expression data sets.MethodsMicroarray data sets of OA and RA were obtained from the Gene Expression Omnibus (GEO). By integrating multiple gene data sets, specific differentially expressed genes (DEGs) were identified. The Gene Ontology (GO) functional annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and protein–protein interaction (PPI) network analysis of DEGs were conducted to determine hub genes and pathways. The “Cell Type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT)” algorithm was employed to evaluate the immune infiltration cells (IICs) profiles in OA and RA. Moreover, mouse models of RA and OA were established, and selected hub genes were verified in synovial tissues with quantitative polymerase chain reaction (qPCR).ResultsA total of 1116 DEGs were identified between OA and RA. GO functional enrichment analysis showed that DEGs were enriched in regulation of cell morphogenesis involved in differentiation, positive regulation of neuron differentiation, nuclear speck, RNA polymerase II transcription factor complex, protein serine/threonine kinase activity and proximal promoter sequence-specific DNA binding. KEGG pathway analysis showed that DEGs were enriched in EGFR tyrosine kinase inhibitor resistance, ubiquitin mediated proteolysis, FoxO signaling pathway and TGF-beta signaling pathway. Immune cell infiltration analysis identified 9 IICs with significantly different distributions between OA and RA samples. qPCR results showed that the expression levels of the hub genes (RPS6, RPS14, RPS25, RPL11, RPL27, SNRPE, EEF2 and RPL19) were significantly increased in OA samples compared to their counterparts in RA samples (P < 0.05).ConclusionThis large-scale gene analyses provided new insights for disease-associated genes, molecular mechanisms as well as IICs profiles in OA and RA, which may offer a new direction for distinguishing diagnosis and treatment between OA and RA.

Establishment of a Lung Cancer Discriminative Model Based on an Optimized Support Vector Machine Algorithm and Study of Key Targets of Wogonin in Lung Cancer.

An optimized support vector machine model was used to construct a lung cancer diagnosis model based on serological indicators, and a molecular regulation model of Wogonin, a component of Scutellaria baicalensis, was established. Serological indexes of patients were collected, the grid search method was used to identify the optimal penalty coefficient C and parameter g of the support vector machine model, and the benign and malignant auxiliary diagnosis model of isolated pulmonary nodules based on serological indicators was established. The regulatory network and key targets of Wogonin in lung cancer were analyzed by network pharmacology, and key targets were detected by western blot. The relationship between serological susceptibility genes and key targets of Wogonin was established, and the signaling pathway of Wogonin regulating lung cancer was constructed. After support vector machine parameter optimization (C = 90.597, g = 32), the accuracy of the model was 90.8333%, with nine false positives and two false negative cases. Ontology functional analysis of 67 common genes between Wogonin targets and lung cancer–related genes showed that the targets were associated with biological processes involved in peptidye-serine modification and regulation of protein kinase B signaling; cell components in the membrane raft and chromosomal region; and molecular function in protein serine/threonine kinase activity and heme binding. Kyoto Encyclopedia of Genes and Genomes analysis showed that the regulation pathways involved the PI3K-Akt signaling pathway, ERBB signaling pathway, and EGFR tyrosine kinase inhibitor resistance. In vitro analyses using lung cancer cells showed that Wogonin led to significantly increased levels of cleaved caspase-3 and Bad and significantly decreased Bcl-2 expression in a concentration-dependent manner. ErbB4 expression also significantly decreased in lung cancer cells after treatment with Wogonin. A regulatory network of Wogonin regulating lung cancer cell apoptosis was constructed, including the participation of serological susceptibility genes. There is a certain regulatory effect between the serological indexes that can be used in the diagnosis of lung cancer and the key targets of Chinese herbal medicine treatment of lung cancer, which provides a new idea for the diagnosis, treatment and prognosis of clinical lung cancer.

Network Pharmacology-Based Identification of Potential Targets of Lonicerae japonicae Flos Acting on Anti-Inflammatory Effects.

Lonicerae japonicae flos (LJF) is widely used for the treatment of inflammation-related diseases in traditional Chinese medicine (TCM). To clarify the anti-inflammatory mechanism of LJF, 29 compounds with high content in LJF were selected for network pharmacology. Then, a comprehensive network pharmacology strategy was implemented, which involved compound-inflammation-target construction, protein-protein interaction (PPI) network analysis, and enrichment analysis. Finally, molecular docking and in vitro experiments were performed to verify the anti-inflammatory activity and targets of the key compound. As a result, 279 inflammation-associated proteins were identified, which are mainly involved in the AGE/RAGE signaling pathway in diabetic complications, the HIF-1 signaling pathway, the PI3K-AKT signaling pathway, and EGFR tyrosine kinase inhibitor resistance. A total of 12 compounds were linked to more than 35 targets, including apigenin, kaempferol, quercetin, luteolin, and ferulic acid. The results of molecular docking showed that AKT has the most binding activity, exhibiting certain binding activity with 10 compounds, including vanillic acid, protocatechuic acid, secologanic acid, quercetin, and luteolin; the results of qRT-PCR and WB confirmed that two key compounds, secologanic acid and luteolin, could significantly decrease the secretion of TNF-α and the AKT expression of RAW264.7 murine macrophages stimulated by LPS (lipopolysaccharide). These results demonstrate that the comprehensive strategy can serve as a universal method to illustrate the anti-inflammatory mechanisms of traditional Chinese medicine by identifying the pathways or targets.

KCa channel blockers increase effectiveness of the EGF receptor TK inhibitor erlotinib in non-small cell lung cancer cells (A549)

Non-small cell lung cancer (NSCLC) has a poor prognosis with a 5 year survival rate of only ~ 10%. Important driver mutations underlying NSCLC affect the epidermal growth factor receptor (EGFR) causing the constitutive activation of its tyrosine kinase domain. There are efficient EGFR tyrosine kinase inhibitors (TKIs), but patients develop inevitably a resistance against these drugs. On the other hand, KCa3.1 channels contribute to NSCLC progression so that elevated KCa3.1 expression is a strong predictor of poor NSCLC patient prognosis. The present study tests whether blocking KCa3.1 channels increases the sensitivity of NSCLC cells towards the EGFR TKI erlotinib and overcomes drug resistance. mRNA expression of KCa3.1 channels in erlotinib-sensitive and -resistant NSCLC cells was analysed in datasets from Gene expression omnibus (GEO) and ArrayExpress. We assessed proliferation and migration of NSCLC cells. These (live cell-imaging) experiments were complemented by patch clamp experiments and Western blot analyses. We identified three out of four datasets comparing erlotinib-sensitive and -resistant NSCLC cells which revealed an altered expression of KCa3.1 mRNA in erlotinib-resistant NSCLC cells. Therefore, we evaluated the combined effect of erlotinib and the KCa3.1 channel inhibition with sencapoc. Erlotinib elicits a dose-dependent inhibition of migration and proliferation of NSCLC cells. The simultaneous application of the KCa3.1 channel blocker senicapoc increases the sensitivity towards a low dose of erlotinib (300 nmol/L) which by itself has no effect on migration and proliferation. Partial erlotinib resistance can be overcome by KCa3.1 channel blockade. The sensitivity towards erlotinib as well as the potentiating effect of KCa3.1 blockade is further increased by mimicking hypoxia. Our results suggest that KCa3.1 channel blockade may constitute a therapeutic concept for treating NSCLC and overcome EGFR TKI resistance. We propose that this is due to complementary mechanisms of action of both blockers.

A review of research progress on mechanisms and overcoming strategies of acquired osimertinib resistance.

Targeted therapy with epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKIs) is the standard first-line treatment for advanced EGFR-mutated non-small cell lung cancer (NSCLC). Third-generation EGFR-TKIs, represented by osimertinib, have been approved to overcome the EGFR T790M mutation in patients who are resistant to first- or second-generation TKIs, which brings more survival benefits for patients with advanced NSCLC. However, resistance to the third generation of EGFR-TKIs is still inevitable. Acquired drug resistance is the main reason for limiting the long-term effectiveness of targeted therapy in EGFR-mutated NSCLC patients. The mechanism of EGFR-TKI resistance of the third generation has become a focus of research in the field of targeted therapy. In this review, we summarize the research progress in resistance mechanisms of advanced NSCLC to osimertinib and the potential overcoming strategies and hope to provide a clinical basis and ideas for precision treatment of NSCLC.

Co-delivery of gefitinib and hematoporphyrin by aptamer-modified fluorinated dendrimer for hypoxia alleviation and enhanced synergistic chemo-photodynamic therapy of NSCLC

Although epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)-based molecular targeted therapy are proved to be effective in the treatment of non-small cell lung cancer (NSCLC) with EGFR mutation, its efficacy is limited by the acquired drug resistance. The combination of EGFR-TKIs with photodynamic therapy (PDT) has been explored to combat NSCLC with promising synergistic results. However, hypoxic tumor microenvironment is associated with the development of EGFR-TKIs resistance and severely limits the efficacy of PDT. Here, we synthesized an aptamer modified fluorinated dendrimer (APF) as a drug carrier and prepared nanocomplexes APFHG by encapsulation of gefitinib (Gef) and hematoporphyrin (Hp). APF has good oxygen-carrying capacity, high drug entrapment efficiency, and could release Gef and Hp in response to intracellular pH. APF can specifically recognize EGFR-positive NSCLC cells and effectively improve the tumor hypoxic microenvironment due to the targeting effect of aptamer and the good oxygen-carrying capacity of the fluorinated dendrimer. Under the laser irradiation, APFHG can significantly increase the production of the intracellular reactive oxygen species and produce a synergistic therapeutic effect in inhibition of cellular growth and induction of cell cycle arrest and apoptosis on both Gef-sensitive and Gef-resistant EGFR-mutant NSCLC cells through PDT/molecular targeted therapy. This work indicates that fluorinated dendrimer could be a potent drug delivery platform to overcome hypoxia-related resistance and the co-delivery of EGFR-TKI and photosensitizer by the fluorinated dendrimer could be a promising therapeutic approach for reversal of EGFR-TKIs resistance in EGFR mutation-positive NSCLC.

1366TiP Tepotinib + osimertinib for EGFR-mutant NSCLC with resistance to first-line osimertinib due to MET amplification (METamp): INSIGHT 2

METamp is a mechanism of acquired resistance to EGFR tyrosine kinase inhibitors (TKIs), occurring in 7–15% of patients (pts) who progress on first-line osimertinib. Tepotinib is an oral, once daily (QD), highly selective, potent MET TKI. Tepotinib + gefitinib improved outcomes vs chemotherapy in pts with EGFR-mutant METamp NSCLC and EGFR TKI resistance (INSIGHT; NCT01982955). Median progression-free survival (PFS) was 16.6 vs 4.2 months (HR=0.13; 90% CI: 0.04, 0.43) and median overall survival (OS) was 37.3 vs 13.1 months (HR=0.08; 90% CI: 0.01, 0.51).

Phospho-EGFRTyr992 is synergistically repressed by co-inhibition of histone deacetylase (HDAC) and phosphatidylinositol 3-kinase (PI3K), which attenuates resistance to erlotinib in head and neck cancer cells.

BackgroundErlotinib is a commonly used epidermal growth factor receptor (EGFR)-targeted therapeutic choice for head and neck squamous cell carcinoma; however, its efficacy is largely compromised by cancer cell resistance. Understanding and targeting the erlotinib adaptive mechanisms of squamous cell carcinoma of the head and neck (HNSCC) cancer cells are still pressing challenges. This study aimed to elucidate the cooperative erlotinib-sensitizing mechanisms of histone deacetylase (HDAC) and phosphatidylinositol 3-kinase (PI3K) co-inhibition, which will be helpful in gaining a better understanding of the mechanism of EGFR-tyrosine kinase inhibitor (TKI) resistance in head and neck cancer cells.MethodsHigh-content screening (HCS) was performed to analyze the cell counts of different treatment groups and their drug-sensitizing effect phenotype. Western blotting and immunofluorescence staining assays were used to measure and locate the expression of proteins in the FaDu and TU212 cells. Annexin V/PI and DAPI staining were also used to determine the ratio of apoptotic cells and different cell cycle phases.ResultsThe expression of phosphor-EGFRTyr992 was significantly increased in erlotinib-treated FaDu cells compared with dimethyl sulfoxide (DMSO)-treated FaDu cells. Meanwhile, erlotinib + vorinostat + copanlisib jointly attenuated the expression of phosphor-EGFRTyr1068 and phosphor-EGFRTyr992, but stimulated the expression of E-cadherin. Moreover, we found that the tri-drug group also impaired the expression of phosphor-STAT3Ser727 and its relevant activators, including phosphor-SrcTyr416.ConclusionsThese findings indicate that HDACs and PI3K co-inhibition sensitizes erlotinib via inactivation of the phosphor-EGFRTyr1068-induced RTK-STAT3 axis. However, PI3K inhibition was sufficient to sensitize TU212 cells to erlotinib, providing new perspectives for the further clinical study of erlotinib + vorinostat + copanlisib as a potential combination therapeutic solution for EGFR responsive reactivation-induced resistance to erlotinib.

Lurasidone Sensitizes Cancer Cells to Osimertinib by Inducing Autophagy and Reduction of Survivin.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are key drugs in cancer treatment due to their minor adverse effects and outstanding anticancer effects. However, drugs for overcoming EGFR-TKI resistance are not in clinical use so far. Therefore, to overcome resistance, we focused on lurasidone, a new antipsychotic drug, due to its mild adverse effect profile from the viewpoint of drug repositioning. We explored the effects of lurasidone alone or in combination with EGFR-TKI on the growth of osimertinib-resistant cancer cells the anti-apoptotic marker expression such as survivin, and autophagy levels by LC-3B expression. Within a non-toxic concentration range in normal cells, lurasidone and osimertinib combination therapy showed a growth-inhibitory effect in osimertinib-resistant cancer cells in vitro and in vivo. Furthermore, lurasidone decreased survivin expression and mildly induced autophagy. Lurasidone may increase the sensitivity to osimertinib in osimertinib-resistant cancer cells in drug repurposing.

Tumor immune microenvironment in epidermal growth factor receptor-mutated non-small cell lung cancer before and after epidermal growth factor receptor tyrosine kinase inhibitor treatment: a narrative review.

ObjectiveTo review and summarize the characteristics of the tumor immune microenvironment (TIME) in EGFR-mutated non-small cell lung cancer (NSCLC) after EGFR-TKI treatment and its role in TKI resistance.BackgroundLung cancer is one of the most commonly diagnosed cancer and the leading cause of death from cancer in both men and women around the world. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are considered a first-line treatment for EGFR-mutated NSCLC. However, almost all patients eventually develop acquired resistance to EGFR-TKIs, with a median progression-free survival (PFS) of 9–14 months. As immunotherapy has developed, it has become apparent that interactions between the TIME and tumor cells also affect EGFR-TKI treatment. The TIME comprises a variety of components but previous studies of the TIME following EGFR-TKI therapy of NSCLC are inconsistent. Here, we reviewed the characteristics of the TIME in NSCLC after EGFR-TKI treatment and its role in TKI resistance.MethodsPubMed, Embase, and Web of Science were searched to July 1, 2021 with the following key words: “NSCLC”, “EGFR”, and “immunotherapy”.ConclusionsThe TIME of EGFR-mutated NSCLC is different from that of non-mutated NSCLC, an explanation for EGFR-mutated NSCLC displaying a poor response to ICIs. The TIME of EGFR-mutated NSCLC also changes during treatment with EGFR-TKIs. The TIME in EGFR-TKI-resistant lung cancer can be summarized as follows: (I) compared with EGFR-TKI-sensitive tumors, EGFR-TKI-resistant tumors have a greater number of immunosuppressive cells and fewer immune-activated cells, while the tumor microenvironment is in an immunosuppressive state; (II) tumor cells and immunosuppressive cells secrete multiple negative immune regulatory factors, inhibit the recognition and presentation of tumor antigens and the antitumor effect of immune cells, resulting in immune escape; 3.EGFR-TKI-resistant tumors promote EMT. These three characteristics interact, resulting in a regulatory signaling network, which together leads to EGFR-TKI resistance.

Coregulation of pathways in lung cancer patients with EGFR mutation: therapeutic opportunities.

Epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma are a frequent class of driver mutations. Single EGFR tyrosine kinase inhibitor (TKI) provides substantial clinical benefit, but almost nil radiographic complete responses. Patients invariably progress, although survival can reach several years with post-treatment therapies, including EGFR TKIs, chemotherapy or other procedures. Endeavours have been clinically oriented to manage the acquisition of EGFR TKI-resistant mutations; however, basic principles on cancer evolution have not been considered in clinical trials. For years, evidence has displayed rapidly adaptive mechanisms of resistance to selective monotherapy, posing several dilemmas for the practitioner. Strict adherence to non-small cell lung cancer (NSCLC) guidelines is not always practical for addressing the clinical progression that EGFR-mutant lung adenocarcinoma patients suffer. The purpose of this review is to highlight regulatory mechanisms and signalling pathways that cause therapy-induced resistance to EGFR TKIs. It suggests combinatorial therapies that target EGFR, as well as potential mechanisms underlying EGFR-mutant NSCLC, alerting the reader to clinical opportunities that may lead to a deeper and more durable response. Molecular reprogramming contributes to EGFR TKI resistance, and the compiled information is relevant in understanding the development of new combined targeted strategies in EGFR-mutant NSCLC.

Kaempferol potentiates the sensitivity of pancreatic cancer cells to erlotinib via inhibition of the PI3K/AKT signaling pathway and epidermal growth factor receptor.

Erlotinib (ERL) is an epidermalgrowthfactorreceptor(EGFR) tyrosine kinase inhibitor (TKI) of pancreatic cancer (PC). However, the clinical efficacy of ERL is limited due to the activationof alternative pathways thatbypassthe EGFRsignaling. Kaempferol (KAE), a natural flavonoid compound, has been reported to possess potent anti-tumor and anti-inflammatory properties, and in this study, we aimed at identifying the sensitization effect of KAE on ERL monotherapy in PC cells and mouse models. Briefly, the CCK-8, colony formation, and flow cytometry were used to assess the proliferation and apoptosis of two PC cell lines in response to a treatment combination of KAE and ERL. Additionally, the drug-disease targets and related anti-PC mechanisms of KAE and ERL were predicted with a network pharmacology method. The survival outcome for PC patients with EGFR differential expression was evaluated through survival analysis. The molecular docking technique predicted the affinity between KAE and EGFR. Moreover, western blot (WB) and immunohistochemistry (IHC) analyses were applied to verify the expression levels of related proteins. As a result, in vitro results showed that the combination of KAE and ERL significantly inhibited cell proliferation and promoted cell apoptosis compared to that with ERL alone. Network pharmacology results demonstrated that KAE sensitized PC to ERL treatment may likely be related to the PI3K/AKT signaling pathway and EGFR TKI resistance. Survival analysis illustrated that PC patients with high expression of EGFR had a relative lower survival rate. Molecular docking results further suggested that KAE had a high binding affinity of - 8.9kcal/mol with EGFR. WB results indicated that the combination of KAE and ERL dramatically downregulated the expression levels of p-EGFR, p-AKT, p-ERK1/2, and Bcl-2, and upregulated the expression levels of cleaved caspase-9, cleaved PARP, and Bax. The in vivo results revealed that treatment combination of KAE and ERL further reduced the volume and weight of subcutaneous grafted tumors. IHC results confirmed the WB results. These data imply that KAE may be a valid therapeutic candidate to potentiate PC cell sensitivity to ERL via inhibiting PI3K/AKT and EGFR signaling.

Inhibition of miR-185-3p Confers Erlotinib Resistance Through Upregulation of PFKL/MET in Lung Cancers

Erlotinib (ER), as an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), has a significant therapeutic effect in lung cancers. However, EGFR TKI resistance inevitably occurs after treatment for approximately 12 months, which weakens its antitumor effect. Here, we identified miR-185-3p as a significantly downregulated microRNA responsible for acquired EGFR TKI resistance in cells and patients with lung cancer. qRT-PCR and Western Blot were performed to determine the relative expression of miR-185-3p in ER-resistant tumor tissues and cells. The viability and apoptosis of lung cancer cells were evaluated by Cell Counting Kit-8 (CCK8) assay and flow cytometry, respectively. The binding between miR-185-3p and liver-type phosphofructokinase (PFKL) was verified by dual luciferase assay. It was found that overexpression of miR-185-3p conferred ER sensitivity in lung cancer cell lines. MiR-185-3p was downregulated in ER-resistant lung cancer cells (H1299/ER and A549/ER). MiR-185-3p inhibited proliferation and induced cell apoptosis in ER-resistant cells. Mechanistically, miR-185-3p downregulation contributed to ER resistance through upregulating the PFKL. Moreover, Mesenchymal to epithelial transition (MET) oncoprotein promoted EGFR-TKI resistance by regulating miR-185-3p and PFKL. These findings revealed a novel mechanism in which downregulation of miR-185-3p may induce overexpression of PFKL and MET and confer ER resistance in lung cells. Combination of PFKL/MET inhibitors and EGFR TKIs could be a rational therapeutic approach for lung cancer patients with EGFR mutation.

Lung Cancer Models Reveal Severe Acute Respiratory Syndrome Coronavirus 2–Induced Epithelial-to-Mesenchymal Transition Contributes to Coronavirus Disease 2019 Pathophysiology

IntroductionCoronavirus disease 2019 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which enters host cells through the cell surface proteins ACE2 and TMPRSS2. MethodsUsing a variety of normal and malignant models and tissues from the aerodigestive and respiratory tracts, we investigated the expression and regulation of ACE2 and TMPRSS2. ResultsWe find that ACE2 expression is restricted to a select population of epithelial cells. Notably, infection with SARS-CoV-2 in cancer cell lines, bronchial organoids, and patient nasal epithelium induces metabolic and transcriptional changes consistent with epithelial-to-mesenchymal transition (EMT), including up-regulation of ZEB1 and AXL, resulting in an increased EMT score. In addition, a transcriptional loss of genes associated with tight junction function occurs with SARS-CoV-2 infection. The SARS-CoV-2 receptor, ACE2, is repressed by EMT through the transforming growth factor-β, ZEB1 overexpression, and onset of EGFR tyrosine kinase inhibitor resistance. This suggests a novel model of SARS-CoV-2 pathogenesis in which infected cells shift toward an increasingly mesenchymal state, associated with a loss of tight junction components with acute respiratory distress syndrome-protective effects. AXL inhibition and ZEB1 reduction, as with bemcentinib, offer a potential strategy to reverse this effect. ConclusionsThese observations highlight the use of aerodigestive and, especially, lung cancer model systems in exploring the pathogenesis of SARS-CoV-2 and other respiratory viruses and offer important insights into the potential mechanisms underlying the morbidity and mortality of coronavirus disease 2019 in healthy patients and patients with cancer alike.

Combined FGFR and Akt pathway inhibition abrogates growth of FGFR1 overexpressing EGFR-TKI-resistant NSCLC cells

EGFR tyrosine kinase inhibitor (TKI) resistance in non-small cell lung cancer (NSCLC) patients is inevitable. Identification of resistance mechanisms and corresponding targeting strategies can lead to more successful later-line treatment in many patients. Using spectrometry-based proteomics, we identified increased fibroblast growth factor receptor 1 (FGFR1) expression and Akt activation across erlotinib, gefitinib, and osimertinib EGFR-TKI-resistant cell line models. We show that while combined EGFR-TKI and FGFR inhibition showed some efficacy, simultaneous inhibition of FGFR and Akt or PI3K induced superior synergistic growth inhibition of FGFR1-overexpressing EGFR-TKI-resistant NSCLC cells. This effect was confirmed in vivo. Only dual FGFR and Akt inhibition completely blocked the resistance-mediating signaling pathways downstream of Akt. Further, increased FGFR1 expression was associated with significantly lower PFS in EGFR-TKI-treated NSCLC patients, and increased FGFR1 were demonstrated in a few post- vs. pre-EGFR-TKI treatment clinical biopsies. The superior therapeutic benefit of combining FGFR and Akt inhibitors provide the rationale for clinical trials of this strategy.