EGFR activation limits the response of liver cancer to lenvatinib.

Hepatocellular carcinoma (HCC)-the most common form of liver cancer-is an aggressive malignancy with few effective treatment options1. Lenvatinib is a small-molecule inhibitor of multiple receptor tyrosine kinases that is used for the treatment of patients with advanced HCC, but this drug has only limited clinical benefit2. Here, using a kinome-centred CRISPR-Cas9 genetic screen, we show that inhibition of epidermal growth factor receptor (EGFR) is synthetic lethal with lenvatinib in liver cancer. The combination of the EGFR inhibitor gefitinib and lenvatinib displays potent anti-proliferative effects in vitro in liver cancer cell lines that express EGFR and in vivo in xenografted liver cancer cell lines, immunocompetent mouse models and patient-derived HCC tumours in mice. Mechanistically, inhibition of fibroblast growth factor receptor (FGFR)  by lenvatinib treatment leads to feedback activation of the EGFR-PAK2-ERK5 signalling axis, which is blocked by EGFR inhibition. Treatment of 12 patients with advanced HCC who were unresponsive to lenvatinib treatment with the combination of lenvatinib plus gefitinib (trial identifier NCT04642547) resulted in meaningful clinical responses. The combination therapy identified here may represent a promising strategy for the approximately 50% of patients with advanced HCC who have high levels of EGFR.

SubCellBarCode: Proteome-wide Mapping of Protein Localization and Relocalization.

Subcellular localization is a main determinant of protein function; however, a global view of cellular proteome organization remains relatively unexplored. We have developed a robust mass spectrometry-based analysis pipeline to generate a proteome-wide view of subcellular localization for proteins mapping to 12,418 individual genes across five cell lines. Based on more than 83,000 unique classifications and correlation profiling, we investigate the effect of alternative splicing and protein domains on localization, complex member co-localization, cell-type-specific localization, as well as protein relocalization after growth factor inhibition. Our analysis provides information about the cellular architecture and complexity of the spatial organization of the proteome; we show that the majority of proteins have a single main subcellular location, that alternative splicing rarely affects subcellular location, and that cell types are best distinguished by expression of proteins exposed to the surrounding environment. The resource is freely accessible via www.subcellbarcode.org.

EGFR-T790M Mutation-Derived Interactome Rerouted EGFR Translocation Contributing to Gefitinib Resistance in Non-Small Cell Lung Cancer.

Secondary mutation, T790M, conferring tyrosine kinase inhibitors (TKIs) resistance beyond oncogenic epidermal growth factor receptor (EGFR) mutations presents a challenging unmet need. Although TKI-resistant mechanisms are intensively investigated, the underlying responses of cancer cells adapting drug perturbation are largely unknown. To illuminate the molecular basis linking acquired mutation to TKI resistance, affinity purification coupled mass spectrometry was adopted to dissect EGFR interactome in TKI-sensitive and TKI-resistant non-small cell lung cancer cells. The analysis revealed TKI-resistant EGFR-mutant interactome allocated in diverse subcellular distribution and enriched in endocytic trafficking, in which gefitinib intervention activated autophagy-mediated EGFR degradation and thus autophagy inhibition elevated gefitinib susceptibility. Alternatively, gefitinib prompted TKI-sensitive EGFR translocating toward cell periphery through Rab7 ubiquitination which may favor efficacy to TKIs suppression. This study revealed that T790M mutation rewired EGFR interactome that guided EGFR to autophagy-mediated degradation to escape treatment, suggesting that combination therapy with TKI and autophagy inhibitor may overcome acquired resistance in non-small cell lung cancer.

PCK2 induces gefitinib resistance by suppresses ferroptosis in non-small cell lung cancer.

OBJECTIVES: This study aimed to explore the involvement of phosphoenolpyruvate carboxykinase 2 (PCK2) in gefitinib-resistant non-small cell lung cancer (NSCLC) cells and assess its feasibility as a therapeutic target against gefitinib resistance. METHODS: Gefitinib-resistant cell lines, PC9GR and HCC827GR, were generated through progressive exposure of parental cells to escalating concentrations of gefitinib. Transcriptomic analysis encompassed the treatment of PC9 and PC9GR cells with gefitinib or vehicle, followed by RNA extraction, sequencing, and subsequent bioinformatic analysis. Cell viability was determined via CCK-8 assay, while clonogenic assays assessed colony formation. Apoptosis was detected utilizing the Annexin V-FITC/7AAD kit. Iron ion concentrations were quantified using FerroOrange. mRNA analysis was conducted through quantitative RT-PCR. Western blotting was employed for protein analysis. H&E and immunohistochemical staining were performed on tumor tissue sections. RESULTS: The results revealed that depletion or inhibition of PCK2 significantly enhanced gefitinib's efficacy in inducing cell growth arrest, apoptosis, and ferroptosis in resistant NSCLC. Moreover, PCK2 knockdown led to the downregulation of key ferroptosis-related proteins, GPX4 and SLC7A11, while upregulating ASCL4. Conversely, overexpression of PCK2 in gefitinib-sensitive cells rendered resistance to gefitinib. In vivo experiments using a gefitinib-resistant xenograft model demonstrated that PCK2 silencing not only reduced tumor growth but also considerably increased the anti-tumor effect of gefitinib. CONCLUSIONS: In conclusion, our study presents compelling evidence indicating that PCK2 plays a pivotal role in gefitinib resistance in NSCLC. The modulation of ferroptosis-related proteins and the involvement of Akt activation further elucidate the mechanisms underlying this resistance. Consequently, PCK2 emerges as a promising therapeutic target for overcoming gefitinib resistance in NSCLC, offering a new avenue for the development of more effective treatment strategies.

HDAC1 and FOXK1 mediate EGFR-TKI resistance of non-small cell lung cancer through miR-33a silencing.

BACKGROUND: The development of acquired EGFR-TKI treatment resistance is still a major clinical challenge in the treatment of non-small cell lung cancer (NSCLC). This study aimed to investigate the role of HDAC1/FOXK1/miR-33a signaling in EGFR-TKI resistance. METHODS: The expression levels of miR-33a, HDAC1, and FOXK1 were examined using quantitative polymerase chain reaction (PCR) and bioinformatics analysis. Cell proliferation, migration, and apoptosis were explored by cell number assay, Transwell, and flow cytometry assays, respectively. After overexpression or knockdown of HDAC1, miR-33a expression in the cells, cell functions were tested. Immunoprecipitation and correlation analyses were used to evaluate the interaction between HDAC1 and FOXK1 protein. The tumor-suppressive role of miR-33a was investigated by animal experiments. RESULTS: The suppression of miR-33a increased TKI resistance by affecting cell proliferation, migration, and apoptosis in gefitinib-resistant cells. HDAC1 is the key upstream molecule that inhibits miR-33 expression. HDAC1 upregulation increased gefitinib resistance by its binding to FOXK1 in cells to silence miR-33a expression. MiR-33a overexpression exerts tumor-suppressive effects by negatively regulating ABCB7 and p70S6K1 expression. Moreover, overexpression of miR-33a inhibited tumor growth in a xenograft nude mouse model. CONCLUSIONS: HDAC1/FOXK1 upregulation and miR-33a silencing are new mechanisms of EGFR-TKI resistance in NSCLC.

L-Methionine accentuates anti-tumor action of Gefitinib in Gefitinib-resistant lung adenocarcinoma: Role of EGFR/ERK/AKT signaling and histone H3K36me2 alteration.

Adenocarcinoma, the predominant subtype of non-small cell lung cancer (NSCLC), poses a significant clinical challenge due to its prevalence and aggressive nature. Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor is often susceptible to development of resistance despite being the preferred treatment option for NSCLC. In this study, we investigated the potential of L-Methionine in enhancing the cytotoxicity of Gefitinib and preventing resistance development. In vitro experiment employing the H1975 cell line demonstrated a notable enhancement in cytotoxic efficacy when L-Methionine (10 mM) was combined with Gefitinib, as indicated by a substantial reduction in IC50 values (155.854 ± 1.87 µM vs 45.83 ± 4.83 µM). Complementary in vivo investigations in a lung cancer model corroborated these findings. Co-administration of L-Methionine (100 mg/kg and 400 mg/kg) with Gefitinib (15 mg/kg) for 21 days exhibited marked improvements in therapeutic efficacy, which was observed by macroscopic and histopathological assessments. Mechanistic insights revealed that the enhanced cytotoxicity of the combination stemmed from the inhibition of the EGFR, modulating the downstream cascade of ERK/AKT and AMPK pathways. Concurrently inhibition of p-AMPK-α by the combination also disrupted metabolic homeostasis, leading to the increased production of reactive oxygen species (ROS). Notably, L-Methionine, functioning as a methyl group donor, elevated the expression of H3K36me2 (an activation mark), while reducing the p-ERK activity. Our study provides the first evidence supporting L-Methionine supplementation as a novel strategy to enhance Gefitinib chemosensitivity against pulmonary adenocarcinoma.

Synergistic anticancer effects of ginsenoside CK and gefitinib against gefitinib-resistant NSCLC by regulating the balance of angiogenic factors through HIF-1α/VEGF.

Drug resistance is a serious problem for gefitinib in the treatment of lung cancer. Ginsenoside CK, a metabolite of diol ginsenosides, have many excellent pharmacological activities, but whether ginsenoside CK can overcome gefitinib resistance remains unclear. In our study, the sensitizing activity of ginsenoside CK on gefitinib-resistant non-small cell lung cancer (NSCLC) in vitro and in vivo was investigated. Ginsenoside CK was confirmed to enhance the anti-proliferation, pro-apoptotic and anti-migration effects of gefitinib in primary and acquired resistant NSCLC. Furthermore, the combined administration of CK and gefitinib effectively promoted the sensitivity of lung cancer xenograft to gefitinib in vivo, and the tumor inhibition rate reached 70.97% (vs. gefitinib monotherapy 32.65%). Subsequently, tubule formation experiment and western blot results showed that co-treatment of ginsenoside CK inhibited the angiogenesis ability of HUVEC cells, and inhibited the expression of HIF-1α, VEGF, FGF and MMP2/9. More interestingly, ginsenoside CK co-treatment enhanced the expression of anti-angiogenic factor PF4, increased pericellular envelope, and promoted the normalization of vascular structure. In conclusion, ginsenoside CK improved the resistance of gefitinib by regulating the balance of angiogenic factors through down-regulating the HIF-1α/VEGF signaling pathway, providing a theoretical basis for improving the clinical efficacy of gefitinib and applying combined strategies to overcome drug resistance.

Combination of betulinic acid and EGFR-TKIs exerts synergistic anti-tumor effects against wild-type EGFR NSCLC by inducing autophagy-related cell death via EGFR signaling pathway.

BACKGROUND: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of lung cancer patients with mutated EGFR. However, the efficacy of EGFR-TKIs in wild-type EGFR tumors has been shown to be marginal. Methods that can sensitize EGFR-TKIs to EGFR wild-type NSCLC remain rare. Hence, we determined whether combination treatment can maximize the therapeutic efficacy of EGFR-TKIs. METHODS: We established a focused drug screening system to investigate candidates for overcoming the intrinsic resistance of wild-type EGFR NSCLC to EGFR-TKIs. Molecular docking assays and western blotting were used to identify the binding mode and blocking effect of the candidate compounds. Proliferation assays, analyses of drug interactions, colony formation assays, flow cytometry and nude mice xenograft models were used to determine the effects and investigate the molecular mechanism of the combination treatment. RESULTS: Betulinic acid (BA) is effective at targeting EGFR and synergizes with EGFR-TKIs (gefitinib and osimertinib) preferentially against wild-type EGFR. BA showed inhibitory activity due to its interaction with the ATP-binding pocket of EGFR and dramatically enhanced the suppressive effects of EGFR-TKIs by blocking EGFR and modulating the EGFR-ATK-mTOR axis. Mechanistic studies revealed that the combination strategy activated EGFR-induced autophagic cell death and that the EGFR-AKT-mTOR signaling pathway was essential for completing autophagy and cell cycle arrest. Activation of the mTOR pathway or blockade of autophagy by specific chemical agents markedly attenuated the effect of cell cycle arrest. In vivo administration of the combination treatment caused marked tumor regression in the A549 xenografts. CONCLUSIONS: BA is a potential wild-type EGFR inhibitor that plays a critical role in sensitizing EGFR-TKI activity. BA combined with an EGFR-TKI effectively suppressed the proliferation and survival of intrinsically resistant lung cancer cells via the inhibition of EGFR as well as the induction of autophagy-related cell death, indicating that BA combined with an EGFR-TKI may be a potential therapeutic strategy for overcoming the primary resistance of wild-type EGFR-positive lung cancers.

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.

Tetrahydrobenzothiophene derivatives ameliorate Mia PaCa-2 cell progression and induces apoptosis via inhibiting EGFR2 tyrosine kinase signal.

A series of new thiophene analogues with acarbonitrile-basedmoiety were designed and synthesized via structural optimization. The conjugates were assessed for their in-vitro cytotoxic activity against a human pancreatic cancer cell line (Mia PaCa-2) and among them compound 5b showed IC50 value of 13.37 ± 2.37 µM. The compounds 5b (20 µM & 25 µM) and 7c (30 & 35 µM) also showed reduced clonogenicity, enhanced ROS and decreased mitochondrial membrane potential in Mia PaCa-2 cells. Treatment with these compounds also increased apoptotic population as evident with the double staining assay. Among the evaluated series, compounds 5b, 5g, 7c, and 9a attained a greater inhibitory potency than first generation's reversible EGFR inhibitor, Gefitinib. EGFR2 enzyme inhibitory studies revealed that 5b efficiently and arbitrarily suppressed the development of EGFR2 dependent cells and inhibited the enzymatic activity with an IC50 value of 0.68 µM; interestingly, the most effective molecule 5b with N-methyl piperazine substitution, has 1.29-fold greater potency than well-known EGFR inhibitor Gefitinib and increased Gefitinib's anti-growth impact with 2.04 folds greater against Mia PaCa-2. The in-vitro studies were validated with in-silico docking studies wherein compounds 5b and 7c exhibited binding energies of -8.2 and -7.4 Kcal/mol respectively. The present study reveals that tetrahydrobenzothiophene based analogues could be a promising lead for the evolution of potent chemo preventives over pancreatic cancer.

Design of balanced dual-target inhibitors of EGFR and microtubule.

Motivated by the clinical success of combining tyrosine kinase inhibitors with microtubule-targeted drugs in antitumor treatment, this paper presents a novel combi-targeting design for dual-target inhibitors, featuring arylformylurea-coupled quinazoline backbones. A series of target compounds (10a-10r) were designed, synthesized, and characterized. Biological assessments demonstrated that 10c notably potentiated ten tumor cell lines in vitro, with IC50 values ranging from 1.04 µM to 7.66 µM. Importantly, 10c (IC50 = 10.66 nM) exhibited superior inhibitory activity against EGFR kinases compared to the reference drug Gefitinib (25.42 nM) and reduced phosphorylated levels of EGFR, AKT, and ERK. Moreover, 10c significantly impeded tubulin polymerization, disrupted the intracellular microtubule network in A549 cells, induced apoptosis, led to S-phase cell cycle arrest, and hindered cell migration. In anticancer evaluation tests using A549 cancer-bearing nude mice models, 10c showed a therapeutic effect similar to Gefitinib, but required only half the dosage (15 mg/kg). These findings indicate that compound 10c is a promising dual-target candidate for anticancer therapy.

Facile construction of gefitinib-loaded zeolitic imidazolate framework nanocomposites for the treatment of different lung cancer cells.

Gefitinib (GET) is a revolutionary targeted treatment inhibiting the epidermal growth factor receptor's tyrosine kinase action by competitively inhibiting the ATP binding site. In preclinical trials, several lung cancer cell lines and xenografts have demonstrated potential activity with GET. Response rates neared 25% in preclinical trials for non-small cell lung cancer. Here, we describe the one-pot synthesis of GET@ZIF-8 nanocomposites (NCs) in pure water, encapsulating zeolitic imidazolate framework 8 (ZIF-8). This method developed NCs with consistent morphology and a loading efficiency of 9%, resulting in a loading capacity of 20 wt%. Cell proliferation assay assessed the anticancer effect of GET@ZIF-8 NCs on A549 and H1299 cells. The different biochemical staining (Calcein-AM and PI and 4',6-Diamidino-2-phenylindole nuclear staining) assays assessed the cell death and morphological examination. Additionally, the mode of apoptosis was evaluated by mitochondrial membrane potential (∆ψm) and reactive oxygen species. Therefore, the study concludes that GET@ZIF-8 NCs are pledged to treat lung cancer cells.

OSGIN1 is a novel TUBB3 regulator that promotes tumor progression and gefitinib resistance in non-small cell lung cancer.

BACKGROUND: Oxidative stress induced growth inhibitor 1 (OSGIN1) regulates cell death. The role and underlying molecular mechanism of OSGIN1 in non-small cell lung cancer (NSCLC) are uncharacterized. METHODS: OSGIN1 expression in NSCLC samples was detected using immunohistochemistry and Western blotting. Growth of NSCLC cells and gefitinib-resistant cells expressing OSGIN1 or TUBB3 knockdown was determined by MTT, soft agar, and foci formation assays. The effect of OSGIN1 knockdown on in vivo tumor growth was assessed using NSCLC patient-derived xenograft models and gefitinib-resistant patient-derived xenograft models. Potentially interacting protein partners of OSGIN1 were identified using IP-MS/MS, immunoprecipitation, PLA, and Western blotting assays. Microtubule dynamics were explored by tubulin polymerization assay and immunofluorescence. Differential expression of signaling molecules in OSGIN1 knockdown cells was investigated using phospho-proteomics, KEGG analysis, and Western blotting. RESULTS: We found that OSGIN1 is highly expressed in NSCLC tissues and is positively correlated with low survival rates and tumor size in lung cancer patients. OSGIN1 knockdown inhibited NSCLC cell growth and patient-derived NSCLC tumor growth in vivo. Knockdown of OSGIN1 strongly increased tubulin polymerization and re-established gefitinib sensitivity in vitro and in vivo. Additionally, knockdown of TUBB3 strongly inhibited NSCLC cell proliferation. Mechanistically, we found that OSGIN1 enhances DYRK1A-mediated TUBB3 phosphorylation, which is critical for inducing tubulin depolymerization. The results of phospho-proteomics and ontology analysis indicated that knockdown of OSGIN1 led to reduced propagation of the MKK3/6-p38 signaling axis. CONCLUSIONS: We propose that OSGIN1 modulates microtubule dynamics by enhancing DYRK1A-mediated phosphorylation of TUBB3 at serine 172. Moreover, elevated OSGIN1 expression promotes NSCLC tumor growth and gefitinib resistance through the MKK3/6-p38 signaling pathway. Our findings unveil a new mechanism of OSGIN1 and provide a promising therapeutic target for NSCLC treatment in the clinic.

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.

Silencing of lncRNA LOC105376794 promotes migration, invasion, and Gefitinib resistance of lung adenocarcinoma cells with EGFR 19Del mutation by ATF4/CHOP axis and ERK phosphorylation.

Epidermal growth factor receptor (EGFR) gene exon 19 in-frame deletion (19del) and exon 21 L858R point mutation (21L858R mutation) are prevalent mutations in lung adenocarcinoma. Lung adenocarcinoma patients with 19del presented with a better prognosis than the 21L858R mutation under the same epidermal growth factor receptor tyrosine kinase inhibitor treatment. Our study aimed to uncover the expression of long non-coding RNA LOC105376794 between 19del and 21L858R mutation, and explore the mechanism that regulates cells' biological behavior and gefitinib sensitivity in lung adenocarcinoma cells with 19del. Transcriptome sequencing was conducted to identify differentially expressed lncRNAs between EGFR 19del and 21L858R mutation in serum through the DNBSEQ Platform. Protein-protein interaction network and Kyoto Encyclopedia of Genes and Genomes pathway were conducted to analyze the relationship between lncRNAs and mRNAs through STRING and Dr. TOM. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to measure the expression of lncRNA LOC105376794 in serum and cells. Loss-of-function experiments were used to validate the biological function and gefitinib sensitivity of LOC105376794 in lung adenocarcinoma cells. Protein levels were detected by western blotting. Through transcriptome resequencing and RT-qPCR, we found the expression levels of LOC105376794 in serum were increased in the 19del group compared with the 21L858R mutation group. Inhibition of LOC105376794 promoted proliferation, migration and invasion, and reduced apoptosis of HCC827 and PC-9 cells. The low expression of LOC105376794 reduced gefitinib sensitivity in PC-9 cells. Mechanistically, we found that the knockdown of LOC105376794 suppressed activating transcription factor 4 (ATF4)/C/EBP homologous protein (CHOP) signaling pathway and facilitated the expression of extracellular signal-regulated kinase 1/2 (ERK) phosphorylation. LOC105376794 altered cell biological behavior and gefitinib sensitivity of lung adenocarcinoma cells with 19del through the ATF4/CHOP signaling pathway and the expression of ERK phosphorylation. The results further illustrated the fact that lung adenocarcinoma patients with 19del presented with a more favorable clinical outcome and provided a theoretical basis for treatment strategy for lung adenocarcinoma patients with 19del.

Monitoring drug-target interactions through target engagement-mediated amplification on arrays and in situ.

Drugs are designed to bind their target proteins in physiologically relevant tissues and organs to modulate biological functions and elicit desirable clinical outcomes. Information about target engagement at cellular and subcellular resolution is therefore critical for guiding compound optimization in drug discovery, and for probing resistance mechanisms to targeted therapies in clinical samples. We describe a target engagement-mediated amplification (TEMA) technology, where oligonucleotide-conjugated drugs are used to visualize and measure target engagement in situ, amplified via rolling-circle replication of circularized oligonucleotide probes. We illustrate the TEMA technique using dasatinib and gefitinib, two kinase inhibitors with distinct selectivity profiles. In vitro binding by the dasatinib probe to arrays of displayed proteins accurately reproduced known selectivity profiles, while their differential binding to fixed adherent cells agreed with expectations from expression profiles of the cells. We also introduce a proximity ligation variant of TEMA to selectively investigate binding to specific target proteins of interest. This form of the assay serves to improve resolution of binding to on- and off-target proteins. In conclusion, TEMA has the potential to aid in drug development and clinical routine by conferring valuable insights in drug-target interactions at spatial resolution in protein arrays, cells and in tissues.

Elevated NOX4 promotes tumorigenesis and acquired EGFR-TKIs resistance via enhancing IL-8/PD-L1 signaling in NSCLC.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been widely used for human non-small-cell lung cancer (NSCLC) treatment. However, acquired resistance to EGFR-TKIs is the major barrier of treatment success, and new resistance mechanism remains to be elucidated. In this study, we found that elevated NADPH oxidase 4 (NOX4) expression was associated with acquired EGFR-TKIs resistance. Gefitinib is the first-generation FDA-approved EGFR-TKI, and osimertinib is the third-generation FDA-approved EGFR-TKI. We demonstrated that NOX4 knockdown in the EGFR-TKI resistant cells enabled the cells to become sensitive to gefitinib and osimertinib treatment, while forced expression of NOX4 in the sensitive parental cells was sufficient to induce resistance to gefitinib and osimertinib in the cells. To elucidate the mechanism of NOX4 upregulation in increasing TKIs resistance, we found that knockdown of NOX4 significantly down-regulated the expression of transcription factor YY1. YY1 bound directly to the promoter region of IL-8 to transcriptionally activate IL-8 expression. Interestingly, knockdown of NOX4 and IL-8 decreased programmed death ligand 1 (PD-L1) expression, which provide new insight on TKIs resistance and immune escape. We found that patients with higher NOX4 and IL-8 expression levels showed a shorter survival time compared to those with lower NOX4 and IL-8 expression levels in response to the anti-PD-L1 therapy. Knockdown of NOX4, YY1 or IL-8 alone inhibited angiogenesis and tumor growth. Furthermore, the combination of NOX4 inhibitor GKT137831 and gefitinib had synergistic effect to inhibit cell proliferation and tumor growth and to increase cellular apoptosis. These findings demonstrated that NOX4 and YY1 were essential for mediating the acquired EGFR-TKIs resistance. IL-8 and PD-L1 are two downstream targets of NOX4 to regulate TKIs resistance and immunotherapy. These molecules may be used as potential new biomarkers and therapeutic targets for overcoming TKIs resistance in the future.

KIAA1429 promotes tumorigenesis and gefitinib resistance in lung adenocarcinoma by activating the JNK/ MAPK pathway in an m6A-dependent manner.

Non-small cell lung cancer is the leading cause of cancer related mortality worldwide, and lung adenocarcinoma (LUAD) is one of the most common subtypes. The role of N6-methyladenosine (m6A) modification in tumorigenesis and drug resistance in LUAD remains unclear. In this study, we evaluated the effects of vir-like m6A methyltransferase-associated protein (KIAA1429) depletion on proliferation, migration, invasion, and drug resistance of LUAD cells, and identified m6A-dependent downstream genes influenced by KIAA1429. We found that KIAA1429 activated Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathway as a novel signaling event, which is responsible for tumorigenesis and resistance to gefitinib in LUAD cells. KIAA1429 and MAP3K2 showed high expression in LUAD patients' tissues. Knockdown of KIAA1429 inhibited MAP3K2 expression in an m6A methylation-dependent manner, restraining the progression of LUAD cells and inhibiting growth of gefitinib-resistant HCC827 cells. KIAA1429 positively regulated MAP3K2 expression, activated JNK/ MAPK pathway, and promoted drug resistance in gefitinib-resistant HCC827 cells. We reproduced the in vitro results in nude mouse xenografted with KIAA1429 knockdown cells. Our study showed that the mechanism of m6A KIAA1429-mediated gefitinib resistance in LUAD cells occurs by activating JNK/ MAPK signaling pathway. These findings provide potential targets for molecular therapy and clinical treatment in LUAD patients with gefitinib resistance.

Tanshinone IIA reverses gefitinib resistance in EGFR-mutant lung cancer via inhibition of SREBP1-mediated lipogenesis.

BACKGROUND AND AIM: Gefitinib resistance is an urgent problem to be solved in the treatment of non-small cell lung cancer (NSCLC). Tanshinone IIA (Tan IIA) is one of the main active components of Salvia miltiorrhiza, which exhibits significant antitumor effects. The aim of this study is to explore the reversal effect of Tan IIA on gefitinib resistance in the epidermal growth factor receptor (EGFR)-mutant NSCLC and the underlying mechanism. EXPERIMENTAL PROCEDURE: CCK-8, colony formation assay, and flow cytometry were applied to detect the cytotoxicity, proliferation, and apoptosis, respectively. The changes in lipid profiles were measured by electrospray ionization-mass spectrometry (MS)/MS. Western blot, real-time q-PCR, and immunohistochemical were used to detect the protein and the corresponding mRNA levels. The in vivo antitumor effect was validated by the xenograft mouse model. KEY RESULTS: Co-treatment of Tan IIA enhanced the sensitivity of resistant NSCLC cells to gefitinib. Mechanistically, Tan IIA could downregulate the expression of sterol regulatory element binding protein 1 (SREBP1) and its downstream target genes, causing changes in lipid profiles, thereby reversing the gefitinib-resistance in EGFR-mutant NSCLC cells in vitro and in vivo. CONCLUSIONS AND IMPLICATIONS: Tan IIA improved gefitinib sensitivity via SREBP1-mediated lipogenesis. Tan IIA could be a potential candidate to enhance sensitivity for gefitinib-resistant NSCLC patients.

Inhibition of miR-578 through SOCS2-dependent manner reverses gefitinib resistance in NSCLC cells.

BACKGROUND: Nonsmall-cell lung cancer (NSCLC) has emerged as one of the dreadful lung cancers globally due to its increased mortality rates. Concerning chemotherapy, gefitinib has been employed as an effective first-line treatment drug for NSCLC. Nonetheless, the acquired resistance to gefitinib has remained one of the treatment obstacles of NSCLC, requiring improvement in the therapeutic effect of gefitinib. METHODS: Initially, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and Western blotting (WB) analyses were conducted to measure micro-ribose nucleic acid (miRNA, specifically miR-578) and suppressor of cytokine signaling 2 (SOCS2) levels in the clinical samples. Further, NSCLC cell lines resistance to gefitinib, established in vitro, were transfected by miR-578 inhibitor, miR-578 mimic, and si-SOCS2. Similarly, the xenograft mouse model in vivo was constructed to validate the reversing effect of miR-578. RESULTS: Our findings indicated the increased miR-578 expression levels in the gefitinib resistance group. Further, inhibiting the miR-578 expression substantially reversed the gefitinib resistance. In addition, the miR-578 effect was modulated via the SOCS2 expression level. The decreased gefitinib resistance effect of miR-578 was weakened by inhibiting the SOCS2 expression. CONCLUSION: These findings demonstrated that miR-578 effectively abolished gefitinib resistance by regulating the SOCS2 expression within NSCLC cells in vitro and in vivo. Together, these results will undoubtedly support a reference to provide potential molecular therapeutic targets and clinical treatments for treating NSCLC patients.