CRISPR-mediated ablation of TP53 and EGFR mutations enhances gefitinib sensitivity and anti-tumor efficacy in lung cancer.

Multiple pathogenic single-nucleotide polymorphisms (SNPs) have been identified as contributing factors in the aggravation of cancer prognosis and emergence of drug resistance in various cancers. Here, we targeted mutated EGFR and TP53 oncogenes harboring single-nucleotide missense mutations (EGFR-T790M and TP53-R273H) that are associated with gefitinib resistance. Co-delivery of adenine base editor (ABE) and EGFR- and TP53-SNP specific single-guide RNA via adenovirus (Ad) resulted in precise correction of the oncogenic mutations with high accuracy and efficiency in vitro and in vivo. Importantly, compared with a control group treated only with gefitinib, an EGFR inhibitor, co-treatment with Ad/ABE targeting SNPs in TP53 and EGFR in combination with gefitinib increased drug sensitivity and suppressed abnormal tumor growth more efficiently. Taken together, these results indicate that ABE-mediated correction of dual oncogenic SNPs can be an effective strategy for the treatment of drug-resistant cancers.

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.

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.

FTO/m6A mediates miR-138-5p maturation and regulates gefitinib resistance of lung adenocarcinoma cells by miR-138-5p/LCN2 axis.

BACKGROUND: Lung cancer (LC) occupies an important position in the lethality of cancer patients. Acquired resistance to gefitinib in lung adenocarcinoma (LUAD) seriously affects the therapeutic efficacy of LC. Thus, it is of major scientific and clinical significance to probe the mechanism of gefitinib resistance in LUAD for ameliorating the prognosis of patients. METHODS: The expression of miRNAs in gefitinib-resistant LUAD cells was validated using qRT-PCR. Cell viability was assessed through CCK-8, whereas cell death was examined through PI staining. Changes in the ferroptosis process were evaluated by detecting the intracellular Glutathione (GSH), Malondialdehyde (MDA), and Reactive Oxygen Species (ROS) levels. Downstream targets of miR-138-5p were verified via luciferase reporter and RNA pull-down assays. RIP and qRT-PCR were employed to evaluate pri-miR-138-5p binding to DiGeorge critical region 8 (DGCR8) and the pri-miR-138-5p m6A modification level. Additionally, the impact of fat mass and obesity-associated protein (FTO) on LUAD gefitinib sensitivity was assessed in vivo by constructing a xenograft model. RESULTS: We observed that miR-138-5p was notably diminished in gefitinib-resistant cells. Overexpression of miR-138-5p suppressed viability while facilitated cell death and intracellular ferroptosis in gefitinib-resistant cells. Moreover, lipocalin 2 (LCN2) was the downstream target of miR-138-5p. The biological functions of miR-138-5p on gefitinib-resistant cells was reversed by introduction of LCN2. FTO suppressed the binding of DGCR8 to pri-miR-138-5p through m6A modification, thereby restraining the processing of miR-138-5p. Meanwhile, silencing of FTO enhanced the sensitivity of LUAD to gefitinib treatment. CONCLUSION: FTO suppressed the processing of miR-138-5p and then modulated the proliferation, death, and ferroptosis of gefitinib-resistant cells through the miR-138-5p/LCN2 pathway, which may put forward novel insights for clinically ameliorating the therapeutic effect of gefitinib in LUAD.

GLUT1 promotes cell proliferation via binds and stabilizes phosphorylated EGFR in lung adenocarcinoma.

BACKGROUND: While previous studies have primarily focused on Glucose transporter type 1 (GLUT1) related glucose metabolism signaling, we aim to discover if GLUT1 promotes tumor progression through a non-metabolic pathway. METHODS: The RNA-seq and microarray data were comprehensively analyzed to evaluate the significance of GLUT1 expression in lung adenocarcinoma (LUAD). The cell proliferation, colony formation, invasion, and migration were used to test GLUT1 's oncogenic function. Co-immunoprecipitation and mass spectrum (MS) were used to uncover potential GLUT1 interacting proteins. RNA-seq, DIA-MS, western blot, and qRT-PCR to probe the change of gene and cell signaling pathways. RESULTS: We found that GLUT1 is highly expressed in LUAD, and higher expression is related to poor patient survival. GLUT1 knockdown caused a decrease in cell proliferation, colony formation, migration, invasion, and induced apoptosis in LUAD cells. Mechanistically, GLUT1 directly interacted with phosphor-epidermal growth factor receptor (p-EGFR) and prevented EGFR protein degradation via ubiquitin-mediated proteolysis. The GLUT1 inhibitor WZB117 can increase the sensitivity of LUAD cells to EGFR-tyrosine kinase inhibitors (TKIs) Gefitinib. CONCLUSIONS: GLUT1 expression is higher in LUAD and plays an oncogenic role in lung cancer progression. Combining GLUT1 inhibitors and EGFR-TKIs could be a potential therapeutic option for LUAD treatment.

Relevance and mechanism of STAT3/miR-221-3p/Fascin-1 axis in EGFR TKI resistance of triple-negative breast cancer.

The epidermal growth factor receptor 1 (EGFR) plays a crucial role in the progression of various malignant tumors and is considered a potential target for treating triple-negative breast cancer (TNBC). However, the effectiveness of representative tyrosine kinase inhibitors (TKIs) used in EGFR-targeted therapy is limited in TNBC patients. In our study, we observed that the TNBC cell lines MDA-MB-231 and MDA-MB-468 exhibited resistance to Gefitinib. Treatment with Gefitinib caused an upregulation of Fascin-1 (FSCN1) protein expression and a downregulation of miR-221-3p in these cell lines. However, sensitivity to Gefitinib was significantly improved in both cell lines with either inhibition of FSCN1 expression or overexpression of miR-221-3p. Our luciferase reporter assay confirmed that FSCN1 is a target of miR-221-3p. Moreover, Gefitinib treatment resulted in an upregulation of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in MDA-MB-231 cells. Using Stattic, a small-molecule inhibitor of STAT3, we observed a significant enhancement in the inhibitory effect of Gefitinib on the growth, migration, and invasion of MDA-MB-231 cells. Additionally, Stattic treatment upregulated miR-221-3p expression and downregulated FSCN1 mRNA and protein expression. A strong positive correlation was noted between the expression of STAT3 and FSCN1 in breast cancer tissues. Furthermore, patients with high expression levels of both STAT3 and FSCN1 had a worse prognosis. Our findings suggest that elevated FSCN1 expression is linked to primary resistance to EGFR TKIs in TNBC. Moreover, we propose that STAT3 regulates the expression of miR-221-3p/FSCN1 and therefore modulates resistance to EGFR TKI therapy in TNBC. Combining EGFR TKI therapy with inhibition of FSCN1 or STAT3 may offer a promising new therapeutic option for TNBC.

Identification of Fasudil as a collaborator to promote the anti-tumor effect of lenvatinib in hepatocellular carcinoma by inhibiting GLI2-mediated hedgehog signaling pathway.

Lenvatinib is a frontline tyrosine kinase inhibitor for patients with advanced hepatocellular carcinoma (HCC). However, just 25% of patients benefit from the treatment, and acquired resistance always develops. To date, there are neither effective medications to combat lenvatinib resistance nor accurate markers that might predict how well a patient would respond to the lenvatinib treatment. Thus, novel strategies to recognize and deal with lenvatinib resistance are desperately needed. In the current study, a robust Lenvatinib Resistance index (LRi) model to predict lenvatinib response status in HCC was first established. Subsequently, five candidate drugs (Mercaptopurine, AACOCF3, NU1025, Fasudil, and Exisulind) that were capable of reversing lenvatinib resistance signature were initially selected by performing the connectivity map (CMap) analysis, and fasudil finally stood out by conducting a series of cellular functional assays in vitro and xenograft mouse model. Transcriptomics revealed that the co-administration of lenvatinib and fasudil overcame lenvatinib resistance by remodeling the hedgehog signaling pathway. Mechanistically, the feedback activation of EGFR by lenvatinib led to the activation of the GLI2-ABCC1 pathway, which supported the HCC cell's survival and proliferation. Notably, co-administration of lenvatinib and fasudil significantly inhibited IHH, the upstream switch of the hedgehog pathway, to counteract GLI2 activation and finally enhance the effectiveness of lenvatinib. These findings elucidated a novel EGFR-mediated mechanism of lenvatinib resistance and provided a practical approach to overcoming drug resistance in HCC through meaningful drug repurposing strategies.

FTO promotes gefitinib-resistance by enhancing PELI3 expression and autophagy in non-small cell lung cancer.

The established recognition of N6-methyladenosine (m6A) modification as an indispensable regulatory agent in human cancer is widely accepted. However, the understanding of m6A's role and the mechanisms underlying its contribution to gefitinib resistance is notably limited. Herein, using RT-qPCR, Western blot, Cell proliferation and apoptosis, as well as RNA m6A modification assays, we substantiated that heightened FTO (Fat Mass and Obesity-associated protein) expression substantially underpins the emergence of gefitinib resistance in NSCLC cells. This FTO-driven gefitinib resistance is hinged upon the co-occurrence of PELI3 (Pellino E3 Ubiquitin Protein Ligase Family Member 3) expression and concurrent autophagy activation. Manipulation of PELI3 expression and autophagy activation, including its attenuation, was efficacious in both inducing and overcoming gefitinib resistance within NSCLC cells, as validated in vitro and in vivo. In summary, this study has successfully elucidated the intricate interplay involving FTO-mediated m6A modification, its consequential downstream effect on PELI3, and the concurrent involvement of autophagy in fostering the emergence of gefitinib resistance within the therapeutic context of NSCLC.

cost-effectiveness of aumolertinib as first-line treatment for EGFR-mutated advanced nonsmall-cell lung cancer.

Aim: To evaluate the cost-effectiveness of aumolertinib as the epidermal growth factor receptor-mutated advanced nonsmall-cell lung cancer first-line treatment from the Chinese healthcare system perspective.Methods: A Markov model was developed based on the AENEAS trial. Only direct medical costs were considered in the model. Utilities were obtained from published literature. Sensitivity and scenario analyses were performed to explore the robustness of the model.Results: Compared with gefitinib, aumolertinib yielded an additional 0.941 expected life-years and 0.692 quality-adjusted life-years (QALYs), with an incremental cost of $18,855.55 over a 20-year time horizon. The incremental cost-effectiveness ratios were $20,051.67/life-year and $27,272.29/QALY, that below the willing-to-pay threshold of $38,223.34/QALY.Conclusion: Aumolertinib was a cost-effective alternative first-line treatment for patients with epidermal growth factor receptor-positive advanced nonsmall-cell lung cancer in China.

What is this article about? This study assesses the costs and health outcomes associated with aumolertinib therapy for Chinese patients diagnosed with advanced or metastatic nonsmall cell lung cancer (NSCLC). Aumolertinib therapy is a specific type of medication used to treat a certain type of lung cancer called nonsmall cell lung cancer. It is a newer treatment that targets certain genetic changes in the cancer cells.How was this done? The costs and treatment benefits were estimated using data from the AENEAS trial, provincial medical cost lists and previously published studies. A Markov model was developed to simulate disease progression. Provincial Medical Cost Lists are official lists maintained by different provincial governments in China that specify the drugs and their prices that are covered by the public healthcare system. A Markov Model is a mathematical tool used to predict how a disease might progress over time. It is like a simulation where the possible outcomes of the disease are analyzed, helping to understand the likely course of the disease and how different treatments might affect it.What were the results? The cost of treatment with aumolertinib for Chinese patients with advanced or metastatic NSCLC was considered to be acceptable based on the benefits it provides.What do the study results mean? The results suggest that aumolertinib is a cost-effective treatment for patients with advanced or metastatic NSCLC in China.

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.

Effect of genetic polymorphisms on the pharmacokinetics of gefitinib in healthy Chinese volunteers.

Gefitinib is the first-generation drug of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) metabolised by the cytochrome P450 and transported by P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2). In the present study, the pharmacokinetics of gefitinib in healthy Chinese volunteers was investigated and the effect of genetic polymorphisms on its variability was evaluted.Forty-five healthy volunteers were administered a single dose of gefitinib and the blood samples were used for quantifying the concentration of gefitinib and genotyping fifteen single-nucleotide polymorphisms of cytochrome P450 enzymes (CYP3A4, CYP3A5, CYP2D6, CYP2C9 and CYP2C19) and drug transporters (ABCB1 and ABCG2).CYP3A5*3 (rs776746) polymorphism showed a significant influence, with higher gefitinib AUC0-t in carrier of CC genotype than in CT/TT genotype (BH-adjusted p value <0.05). For CYP2C9*3 (rs1057910), significant differences in pharmacokinetics of gefitinib were detected between carriers of AA and AC genotypes, with higher AUC0-t, AUC0-∞ and Cmax in carrier of AC genotype than in AA gen-otype (BH-adjusted p value <0.05). No associations were found between SNPs in CYP3A4, CYP2D6, CYP2C19, ABCB1, ABCG2 and the pharmacokinetics of gefitinib.The SNPs in CYP3A5*3 (rs776746) and CYP2C9*3 (rs1057910) were found to be associated with altered gefitinib pharmacokinetics in healthy Chinese volunteers.

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.

Establishment of a novel microfluidic co-culture system for simultaneous analysis of multiple indicators of gefitinib sensitivity in colorectal cancer cells.

The therapeutic effect of gefitinib on colorectal cancer (CRC) is unclear, but it has been reported that stromal cells in the tumor microenvironment may have an impact on drug sensitivity. Herein, we established a microfluidic co-culture system and explored the sensitivity of CRC cells co-cultured with cancer-associated fibroblasts (CAFs) to gefitinib. The system consisted of a multichannel chip and a Petri dish. The chambers in the chip and dish were designed to continuously supply nutrients for long-term cell survival and create chemokine gradients for driving cell invasion without any external equipment. Using this system, the proliferation and invasiveness of cells were simultaneously evaluated by quantifying the area of cells and the migration distance of cells. In addition, the system combined with live cell workstation could evaluate the dynamic drug response of co-cultured cells and track individual cell trajectories in real-time. When CRC cells were co-cultured with CAFs, CAFs promoted CRC cell proliferation and invasion and reduced the sensitivity of cells to gefitinib through the exosomes secreted by CAFs. Furthermore, the cells that migrated out of the chip were collected, and EMT-related markers were determined by immunofluorescent and western blot assays. The results demonstrated that CAFs affected the response of CRC cells to gefitinib by inducing EMT, providing new ideas for further research on the resistance mechanism of gefitinib. This suggests that targeting CAFs or exosomes might be a new approach to enhance CRC sensitivity to gefitinib, and our system could be a novel platform for investigating the crosstalk between tumor cells and CAFs and understanding multiple biological changes of the tumor cells in the tumor microenvironment.

Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Cancer: Current Use and Future Prospects.

Tyrosine kinase inhibitors (TKIs) have emerged as a leading targeted cancer therapy, reducing the side effects often seen with non-targeted treatments, especially the damage to healthy cells. To tackle resistance, typically caused by epidermal growth factor receptor (EGFR) mutations, four generations of TKIs have been developed. Each generation has shown improved effectiveness and fewer side effects, resulting in better patient outcomes. For example, patients on gefitinib, a first-generation TKI, experienced a progression-free survival (PFS) of 10 months compared to 5 months with conventional chemotherapy. Second-generation TKI afatinib outperformed erlotinib and extended PFS to 11.1 months compared to 6.9 months with cisplatin. Third-generation TKIs further increased survival to 38.6 months, compared to 31.8 months with first-generation TKIs. This progress demonstrates the ability of newer TKIs to overcome resistance, particularly the T790M mutation, while reducing adverse effects. Ongoing research focuses on overcoming resistance from newer mutations like C797S to further improve patient survival. These developments highlight the significant progress in TKI therapy and the continued effort to refine cancer treatment. Recent research in South Korea shows that third-generation TKIs are ineffective against non-small cell lung cancer (NSCLC) with the C797S mutation. Several trials have started showing promising in vitro and in vivo results, but more trials are needed before clinical approval. This review underscores notable advancements in the field of EGFR TKIs, offering a comprehensive analysis of their mechanisms of action and the progression of various TKI generations in response to resistance.

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

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