Resistant Lung Adenocarcinoma Research Articles

The impact of SOX4‐activated CTHRC1 transcriptional activity regulating DNA damage repair on cisplatin resistance in lung adenocarcinoma

The impact of SOX4‐activated CTHRC1 transcriptional activity regulating DNA damage repair on cisplatin resistance in lung adenocarcinoma

CTBP2 contributes to cisplatin resistance in lung adenocarcinoma by inhibiting generation of reactive oxygen species.

Cisplatin (CP) is commonly used for the initial treatment of lung adenocarcinoma (LUAD). Resistance to CP has long been recognized as a significant obstacle to achieving improved therapeutic outcomes. Nevertheless, the intricate molecular mechanisms underlying the phenomenon remain incompletely understood. The present study utilized the University of ALabama at Birmingham CANcer data analysis Portal (UALCAN) and Gene Expression Profiling Interactive Analysis (GEPIA) databases to conduct an analysis of the expression of C-terminal binding protein 2 (CTBP2) in LUAD. The correlation between CTBP2 expression and survival data was investigated by the Kaplan-Meier (K-M) plotter. Subsequently, the roles of CTBP2 in CP resistance were explored by analyzing cell viability, cell apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) in CP-resistant cells (A549/DDP). Our data indicated that the CTBP2 expression in LUAD exhibited a significant increase compared to the non-malignant tissues. CTBP2 overexpression showed a correlation to poor survival. CTBP2 knockdown significantly enhanced cell sensitivity to CP in A549/DDP cells. The underlying mechanism is related to promoting ROS production and decreasing MMP after CP treatment. CTBP2 expression has been identified as a novel biomarker for resistance to CP, and its downregulation has been found to enhance sensitivity to CP. Therefore, CTBP2 can serve as a predictor related to CP resistance and a viable therapeutic target for CP resistance in LUAD.

Abstract 5958: Exploring AKR1C3 as a therapeutic target to overcome erlotinib resistance in lung adenocarcinoma

Abstract Introduction: Erlotinib has demonstrated promising efficacy in lung adenocarcinoma (LUAD) patients with epidermal growth factor receptor mutation. However, the development of resistance to erlotinib poses a significant challenge in achieving long-lasting treatment responses. Aldo-keto reductase family 1 member C3 (AKR1C3) is associated with tumor progression, drug resistance, and unfavorable prognosis. This study aims to assess the potential of AKR1C3 as a therapeutic target for overcoming erlotinib resistance in LUAD. Methods: AKR1C3 expression was assessed in paired tumor tissues from 100 LUAD patients using reverse transcription quantitative polymerase chain reaction. Both in vitro and in vivo experiments were categorized into four treatment groups: a saline control (CTR), erlotinib (ER), an AKR1C3 inhibitor 3-(4-trifluoromethyl)phenylamino)benzoic acid (BA), and the combination of erlotinib with the AKR1C3 inhibitor (COM). An erlotinib-resistant cell line was established from the LUAD cell line HCC4006. The MTS assay was used to evaluate cell proliferation and viability. The combined effect of erlotinib and the AKR1C3 inhibitor was assessed using Synergyfinder and CompuSyn calculation software. Both cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models of erlotinib resistance to LUAD were established in NSG mice. The mice received daily oral gavage administration of the drugs for 31 days, while tumor volume was monitored biweekly. Results: AKR1C3 expression was significantly upregulated by more than three-fold in LUAD tumor samples compared to normal counterparts (p < 0.0001). After 24 hours of treatment in erlotinib-resistant cells, the ER and BA groups exhibited inhibition rates of 7% and 9%, respectively, while the COM group demonstrated a substantially higher inhibition rate of 45%. Synergyfinder and CompuSyn analysis revealed a synergy score of 12 and a combination index of 0.5 for the COM group, indicating a robust synergistic effect between the two drugs. In the CDX model, the COM group exhibited a tumor volume reduction of 25% in erlotinib-resistant cells and 64% in parental cells compared to the CTR group. In the PDX model, the COM group displayed a significant reduction of 50.4% in tumor volume compared to the CTR group. There was no significant difference in the weight of body and internal organs among the four treatment groups in both xenograft models. Conclusions: AKR1C3 overexpression was observed in the tumor tissues of LUAD patients. The combination of erlotinib and AKR1C3 inhibitor showed promising efficacy in overcoming erlotinib resistance in both in vitro and in vivo experiments. These findings highlight AKR1C3 as a potential therapeutic target for managing erlotinib resistance in LUAD patients. Targeting AKR1C3 represents a novel approach to overcome resistance and enhance treatment outcomes in LUAD patients undergoing erlotinib therapy. Citation Format: William C. Cho, Kwan P. Li, Chi F. Wong, King Y. Fung, James C. Chow, Ka M. Cheung, Jeffrey C. Chan, Eunice Y. Lau. Exploring AKR1C3 as a therapeutic target to overcome erlotinib resistance in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5958.

Abstract 3483: SIRT7 as a potential therapeutic target for drug resistance in lung adenocarcinoma: Insights from histone modification-related genes

Abstract Background: Lung cancer is one of the leading causes of cancer-related deaths worldwide. Understanding the molecular mechanisms underlying its development and progression is crucial for the development of targeted therapies. In recent years, histone modification has emerged as a key player in the epigenetic regulation of gene expression, and its involvement in lung cancer has gained significant attention. Histone modifications, including methylation, acetylation, phosphorylation, and ubiquitination, influence chromatin structure and, consequently, gene transcription. Aberrant histone modifications can lead to dysregulated gene expression patterns, contributing to the initiation and progression of lung cancer. In this study, we investigated the expression patterns of 55 histone modification-related genes and identified an epigenetic tumor regulator as a potential therapeutic target. Methods: We obtained 55 histone modification-related genes from dbHiMo (http://hme.riceblast.snu.ac.kr/). Transcriptomic (n= 576), clinical data (n=706) and survival data (n=641) of lung adenocarcinoma (LUAD) were downloaded from XenaTCGA database (https://xenabrowser.net/). The transcriptomic and IC50 values with 87 lung cancer cell lines and 310 drugs were downloaded from DepMap portal (https://depmap.org/portal/). RNA-seq data of GSE197555 was downloaded from GEO database (https://www.ncbi.nlm.nih.gov/geo/). All statistical analysis was performed using R. Results: Among a total of 55 genes related to histone modifications, 6 genes including KAT2A, SIRT7, CARM1, KDM5B, HDAC1 and PRMT3 were significantly overexpressed in tumor tissues in LUAD transcriptome data from TCGA. Out of these 6 genes, 3 (KAT2A, SIRT7 and CARM1) showed significant differences in survival analysis with disease-free interval in the adjuvant therapy-received TCGA LUAD dataset. All three demonstrated that as their expression levels increased, the prognosis became worse. The expression levels of SIRT7 and KAT2A were highly positively correlated with the IC50 value of trametinib, which is MEK inhibitor. Among these two genes, the expression level of SIRT7 was up-regulated in trametinib-treated group in resistance to MEK inhibitor in the H460 cell line. However, sensitive to MEK inhibitor in A549, the SIRT7 expression level was down-regulated in the trametinib-treated group. Conclusion: The histone modification-related gene SIRT7 was found to be associated with resistance to trametinib. In this study, these findings suggest that SIRT7 may serve as a potential therapeutic target related to drug resistance in combination therapy with dabrafenib and trametinib. Citation Format: Kyoung-Ho Pyo, YoungJoon Park, Gang-Taik Lee, Juwon Ahn, Su-Jin Choi, Qi Kejia, Taeku Lee, Youngtaek Kim, Joon Yeon Hwang, Byoung Chul Cho. SIRT7 as a potential therapeutic target for drug resistance in lung adenocarcinoma: Insights from histone modification-related genes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3483.

Abstract 6596: BRMS1 downregulation alters the tumor microenvironment and induces immunotherapy resistance in lung adenocarcinoma

Abstract Background: Lung cancer is the leading cause of cancer-related deaths globally. During cancer progression, tumor cells interact with tumor-infiltrating immune cells (TIICs) creating an immunosuppressive microenvironment. Therefore, it is essential to delineate the communication dynamics between cancer cells and TIICs to identify novel pathways for therapeutic targeting. BRMS1 is a metastasis suppressor gene that is frequently downregulated in lung adenocarcinoma (LUAD). We, and others, have shown that loss of BRMS1 results in increased distant metastatic disease. Given the strong correlation between immune suppression, metastasis, and immunotherapy resistance we sought to elucidate if BRMS1 contributes to these processes. Specifically, we hypothesized that loss of BRMS1 in LUAD cells influences the immune cell composition, shaping an immunosuppressive microenvironment and decreasing tumor response to immunotherapy. Methods: To experimentally address our hypothesis, we generated KrasG12D P53fl/fl Brms1−/− mice inducing spontaneous tumors with Ad-Cre intratracheal inoculation. RNA-seq scRNA-seq on Brms1+/+ and Brms1−/− tumors, coupled with cell type annotations using mMCP-counter and DCATS were used to identify diverse TIIC subsets. To validate our observation, we performed immunofluorescence and flow cytometry to assess the number of TIICs. To explore the impact of Brms1 loss on the efficacy of anti-PD1 immunotherapy, a syngeneic CMT167 mouse model with BRMS1KD cells implanted in the flank was treated with an anti-PD1 antibody. Results: Differential gene expression analysis of RNA-seq data revealed a reduction in CCL9, CCL24, CLEC1B, PYCARD and other proinflammatory molecules in Brms1−/− tumors. Gene ontology and GSEA highlighted a diminished immune response signature in Brms1−/- tumors. In contrast, hallmark gene sets like IFNγ response, IL6 signaling, and inflammation are highly enriched in Brms1+/+ tumors. mMCP-counter suggested a decrease in CD8+ T cells in Brms1−/- tumors. Likewise, scRNA-seq data confirmed a significant decrease in cytotoxic CD8+ T cells in the Brms1−/− mice. Immunofluorescence and flow cytometric analysis showed a reduction in cytotoxic CD8+ T cells with low proliferative potential (Ki67+) in the Brms1−/− mice. Postmortem on our syngeneic mouse tumors after a 30-day anti-PD1 antibody treatment revealed a significantly larger mean tumor size in the BRMS1KD group compared to the WT group (942.4 mm³ vs. 184 mm³; p<0.023). Immunophenotyping on these tumors using flow cytometry also demonstrated reduced cytotoxic CD8+ T cells in the KD group post-treatment. Conclusion: Our data suggest that reduced BRMS1 expression in LUAD alters CD8+ T cell composition and primary tumor response to immunotherapy. Implications of our findings underscore the potential of BRMS1 as a therapeutic target in the context of immunotherapy-resistant LUAD. Citation Format: Manendra B. Lankadasari, Yuan Liu, Brooke Mastrogiacomo, Yingjie Zhu, Elizabeth G. Dunne, Cameron N. Fick, Choudhary Harsha, Jorge S. Reis-Filho, David R. Jones. BRMS1 downregulation alters the tumor microenvironment and induces immunotherapy resistance in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6596.

FAM83B regulates mitochondrial metabolism and anti-apoptotic activity in pulmonary adenocarcinoma.

Chemotherapy is an effective therapeutic modality; nevertheless, a significant proportion of patients diagnosed with lung adenocarcinoma (LUAD) demonstrate resistance to chemotherapy. Therefore, it is crucial to understand the potential regulatory mechanisms to develop novel treatment strategies. This study aims to understand how increased FAM83B expression impacts mitochondrial activity, cell apoptosis, and chemotherapy effectiveness in LUAD. Multiple assays, such as CCK8, wound healing, EdU, and transwell assays, were employed to confirm the augmented chemotherapy resistance, heightened cell proliferation, migration, and invasion caused by FAM83B overexpression in LUAD cells. Furthermore, MIMP, MTG, and ATP assays were utilized to quantify changes in mitochondrial metabolism. In vitro functional assays were performed to evaluate the influence of FAM83B overexpression on the malignant progression and resistance mechanisms to chemotherapy in LUAD. In the context of this study, it was determined that LUAD patients with increased FAM83B expression had shorter survival times, and tissue samples with FAM83B overexpression were more prone to metastasis compared to primary samples. As a result, FAM83B is identified as an adverse prognostic marker. The mechanistic analysis demonstrated that FAM83B impedes the translocation of calbindin 2 (CALB2) from the cytoplasm to the mitochondria, resulting in the inhibition of apoptosis and the promotion of mitochondrial activity. Consequently, this ultimately confers resistance to chemotherapy in LUAD. Furthermore, the administration of metformin, which blocks mitochondrial oxidative phosphorylation (OXPHOS), can restore sensitivity to drug resistance in LUAD.Taken together, these findings provide substantial evidence supporting the notion that FAM83B enhances chemotherapy resistance in LUAD through the upregulation of mitochondrial metabolism and the inhibition of apoptosis.

NEAT1_1 confers gefitinib resistance in lung adenocarcinoma through promoting AKR1C1-mediated ferroptosis defence

Gefitinib is one of the most extensively utilized epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) for treating advanced lung adenocarcinoma (LUAD) patients harboring EGFR mutation. However, the emergence of drug resistance significantly compromised the clinical efficacy of EGFR-TKIs. Gaining further insights into the molecular mechanisms underlying gefitinib resistance holds promise for developing novel strategies to overcome the resistance and improve the prognosis in LUAD patients. Here, we identified that the inhibitory efficacy of gefitinib on EGFR-mutated LUAD cells was partially dependent on the induction of ferroptosis, and ferroptosis protection resulted in gefitinib resistance. Among the ferroptosis suppressors, aldo-keto reductase family 1 member C1 (AKR1C1) exhibited significant upregulation in gefitinib-resistant strains of LUAD cells and predicted poor progression-free survival (PFS) and overall survival (OS) of LUAD patients who received first-generation EGFR-TKI treatment. Knockdown of AKR1C1 partially reversed drug resistance by re-sensitizing the LUAD cells to gefitinib-mediated ferroptosis. The decreased expression of miR-338-3p contributed to the aberrant upregulation of AKR1C1 in gefitinib-resistant LUAD cells. Furthermore, upregulated long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1_1 (NEAT1_1) sponged miR-338-3p to neutralize its suppression on AKR1C1. Dual-luciferase reporter assay and miRNA rescue experiment confirmed the NEAT1_1/miR-338-3p/AKR1C1 axis in EGFR-mutated LUAD cells. Gain- and loss-of-function assays demonstrated that the NEAT1_1/miR-338-3p/AKR1C1 axis promoted gefitinib resistance, proliferation, migration, and invasion in LUAD cells. This study reveals the effects of NEAT1_1/miR-338-3p/AKR1C1 axis-mediated ferroptosis defence in gefitinib resistance in LUAD. Thus, targeting NEAT1_1/miR-338-3p/AKR1C1 axis might be a novel strategy for overcoming gefitinib resistance in LUAD harboring EGFR mutation.

Long non-coding RNA CCAT1 acts as an oncogene to promote radiation resistance in lung adenocarcinoma: an epigenomics-based investigation.

Long non-coding RNAs (lncRNAs) appear to be the crucial modulators in various processes and critically influence the oncogenesis. As one of the LncRNAs, LncRNA CCAT1 has been reported to be closely associated with the progression multiple cancers, but its role in modulating the radioresistance of lung adenocarcinoma (LUAD) remains unclear. In our present study, we screened the potential radioresistance related LncRNAs in LUAD based on the data from The Cancer Genome Atlas (TCGA) database. Data suggested that CCAT1 was abundantly expressed in LUAD and CCAT1 was significantly associated with poor prognosis and radioresistance. Moreover, our in vitro experiments showed that radiation treatment could trigger elevated expression of CCAT1 in the human LUAD cell lines. Further loss/gain-of-function investigations indicated that CCAT1 knockdown significantly inhibited cell proliferation, migration and promoted cell apoptosis in NCI-H1299 cells under irradiation, whereas CCAT1 overexpression in A549 cells yield the opposite effects. In summary, we identified the promoting role of CCAT1 in radioresistance of LUAD, which may provide a theoretical basis for radiotherapy sensitization of LUAD.

CircSCUBE3 promoted ferroptosis to inhibit lung adenocarcinoma progression.

CircRNAs can regulate ferroptosis and affect cancer development and are promising biomarkers and therapeutic targets in lung cancer. circSCUBE3 is expressed in lung adenocarcinoma (LUAD) tissues. In this study, our purpose was to study the role and regulatory mechanism of circSCUBE3 in LUAD ferroptosis. circSCUBE3 was identified to be significantly downregulated in LUAD samples and cell lines. The expression of biomarkers related to lipid oxidation (4-HNE) and ferroptosis (Ptgs2) was both downregulated in LUAD tissues, suggesting the ferroptosis resistance in LUAD. Erastin, a ferroptosis inducer, was used to stimulate the LUAD cells for 48 h. The cell viability, 4-HNE and Ptgs2 level of LUAD cells were decreased by exposure to erastin while the expression of circSCUBE3 was not significantly altered. We then overexpressed circSCUBE3 in LUAD cells and found it decreased the GSH level and GSH/GSSG ratio in LUAD cells. CircSCUBE3 might serve as an independent factor of ferroptosis and may induce ferroptosis in LUAD by inhibiting GSH synthesis. The loss-of-function experiments were conducted, and circSCUBE3 deficiency reversed the erastin-induced reduction in cell viability, GSH level, GSH/GSSG ratio, mitochondrial membrane potential and elevation in MDA content, Ptgs2, 4-HNE expression as well as lipid ROS production. CircSCUBE3 negatively regulated GPX4 expression in LUAD cells, and the silencing of GPX4 counteracted the impact of circSCUBE3 deficiency on LUAD cell viability as well as ferroptosis, suggesting that circSCUBE3 regulated the GPX4-mediated GSH synthesis in LUAD. CircSCUBE3 was to bind to CREB, which activated the transcription of GPX4. CircSCUBE3 negatively regulated GPX4 expression by competitively interacting with CREB. In the tumor-bearing mouse models, circSCUBE3 silencing promoted tumor growth and reversed the erastin treatment-induced inhibition on tumorigenesis in vivo. In conclusion, circSCUBE3 inhibited LUAD development by promoting ferroptosis via the CREB/GPX4/GSH axis, which might provide a novel option for the LUAD targeted therapy.

MAP4 acts as an oncogene and prognostic marker and affects radioresistance by mediating epithelial–mesenchymal transition in lung adenocarcinoma

PurposeTo explore the effect of microtubule-associated protein 4 (MAP4) on lung adenocarcinoma cells in vitro and evaluate its prognostic value. Radioresistance, indicated by reduced efficiency of radiotherapy, is a key factor in treatment failure in lung adenocarcinoma (LADC). This study aims to explore the primary mechanism underlying the relationship between MAP4 and radiation resistance in lung adenocarcinoma.MethodsWe analysed the expression of MAP4 in lung adenocarcinoma by real-time quantitative polymerase chain reaction (RT‒qPCR), immunohistochemistry (IHC) and bioinformatics online databases, evaluated the prognostic value of MAP4 in lung adenocarcinoma and studied its relationship with clinicopathological parameters. Cox regression analysis and least absolute shrinkage and selection operator (LASSO) regression analysis identified independent prognostic factors associated with lung adenocarcinoma that were used to construct a nomogram, internal validation was performed. We then evaluated the accuracy and clinical validity of the model using a receiver operating characteristic (ROC) curve, time-dependent C-index analysis, a calibration curve, and decision curve analysis (DCA). Scratch assays and transwell assays were used to explore the effect of MAP4 on the migration and invasion of lung adenocarcinoma cells. Bioinformatics analysis, RT‒qPCR, Cell Counting Kit-8 (CCK-8) assays and Western blot experiments were used to study the relationship between MAP4, epithelial–mesenchymal transition (EMT) and radiation resistance in lung adenocarcinoma.ResultsMAP4 expression in lung adenocarcinoma tissues was significantly higher than that in adjacent normal lung tissues. High expression of MAP4 is associated with poorer overall survival (OS) in patients with lung adenocarcinoma. Univariate Cox regression analysis showed that pT stage, pN stage, TNM stage and MAP4 expression level were significantly associated with poorer OS in LADC patients. Multivariate Cox regression analysis and LASSO regression analysis showed that only the pT stage and MAP4 expression level were associated with LADC prognosis. The nomogram constructed based on the pT stage and MAP4 expression showed good predictive accuracy. ROC curves, corrected C-index values, calibration curves, and DCA results showed that the nomogram performed well in both the training and validation cohorts and had strong clinical applicability. The results of in vitro experiments showed that the downregulation of MAP4 significantly affected the migration and invasion of lung adenocarcinoma cells. MAP4 was strongly correlated with EMT-related markers. Further studies suggested that the downregulation of MAP4 can affect the viability of lung adenocarcinoma cells after irradiation and participate in the radiation resistance of lung adenocarcinoma cells by affecting EMT.ConclusionMAP4 is highly expressed in lung adenocarcinoma; it may affect prognosis by promoting the migration and invasion of cancer cells. We developed a nomogram including clinical factors and MAP4 expression that can be used for prognosis prediction in patients with lung adenocarcinoma. MAP4 participates in radiation resistance in lung adenocarcinoma by regulating the radiation-induced EMT process. MAP4 may serve as a biomarker for lung adenocarcinoma prognosis evaluation and as a new target for improving radiosensitivity.

MUC1-EGFR crosstalk with IL-6 by activating NF-κB and MAPK pathways to regulate the stemness and paclitaxel-resistance of lung adenocarcinoma

Background The chemotherapy resistance often leads to chemotherapy failure. This study aims to explore the molecular mechanism by which MUC1 regulates paclitaxel resistance in lung adenocarcinoma (LUAD), providing scientific basis for future target selection. Methods The bioinformatics method was used to analyse the mRNA and protein expression characteristics of MUC1 in LUAD. RT-qPCR and ELISA were used to detect the mRNA and protein expression, flow cytometry was used to detect CD133+ cells, and cell viability was detected by CCK-8 assay. The mRNA-seq was performed to analyse the changes in expression profile, GO and KEGG analysis were used to explore the potential biological functions. Results MUC1 is highly expressed in LUAD patients and is associated with a higher tumour infiltration. In paclitaxel resistance LUAD cells (A549/TAX cells), the expression of MUC1, EGFR/p-EGFR and IL-6 were higher than that of A549 cells, the proportion of CD133+ cells was significantly increased, and the expression of cancer stem cell (CSCs) transcription factors (NANOG, OCT4 and SOX2) were significantly up-regulated. After knocking down MUC1 in A549/Tax cells, the activity of A549/Tax cells was significantly decreased. Correspondingly, the expression of EGFR, IL-6, OCT4, NANOG, and SOX2 were significantly down-regulated. The mRNA-seq showed that knocking down MUC1 affected the gene expression, DEGs mainly enriched in NF-κB and MAPK signalling pathway. Conclusion MUC1 was highly expressed in A549/TAX cells, and MUC1-EGFR crosstalk with IL-6 may be due to the activation of NF-κB and MAPK pathways, which promote the enrichment of CSCs and lead to paclitaxel resistance.

MAFF confers vulnerability to cisplatin-based and ionizing radiation treatments by modulating ferroptosis and cell cycle progression in lung adenocarcinoma

AimsLung cancer is the leading cause of cancer mortality and lung adenocarcinoma (LUAD) accounts for more than half of all lung cancer cases. Tumor elimination is mostly hindered by drug resistance and the mechanisms remain to be explored in LUAD. MethodsCRISPR screens in cell and murine models and single-cell RNA sequencing were conducted, which identified MAF bZIP transcription factor F (MAFF) as a critical factor regulating tumor growth and treatment resistance in LUAD. RNA and ChIP sequencing analyses were performed for transcriptional target expression and specific binding sites of MAFF. Functions of MAFF in inhibiting tumor growth and promoting cisplatin or irradiation efficacy were investigated using cellular and xenograft models. ResultsPatients with lung adenocarcinoma and reduced MAFF expression had worse clinical outcomes. MAFF inhibited tumor cell proliferation by regulating the expression of SLC7A11, CDK6, and CDKN2C, promoting ferroptosis and preventing cell cycle progression from G1 to S. MAFF also conferred tumor cells vulnerable to cisplatin-based or ionizing radiation treatments. MAFF reduction was a final event in the acquisition of cisplatin resistance of LUAD cells. The intracellular cAMP/PKA/CREB1 pathway upregulated MAFF in response to cisplatin-based or ionizing radiation treatments. ConclusionsMAFF suppresses tumor growth, and pharmacological agonists targeting MAFF may improve cisplatin or irradiation therapies for lung adenocarcinoma patients.

SOS2 modulates the threshold of EGFR signaling to regulate osimertinib efficacy and resistance in lung adenocarcinoma.

Son of sevenless 1 and 2 (SOS1 and SOS2) are RAS guanine nucleotide exchange factors (RasGEFs) that mediate physiologic and pathologic receptor tyrosine kinase (RTK)-dependent RAS activation. Here, we show that SOS2 modulates the threshold of epidermal growth factor receptor (EGFR) signaling to regulate the efficacy of and resistance to the EGFR tyrosine kinase inhibitor (EGFR-TKI) osimertinib in lung adenocarcinoma (LUAD). SOS2 deletion (SOS2KO ) sensitized EGFR-mutated cells to perturbations in EGFR signaling caused by reduced serum and/or osimertinib treatment to inhibit phosphatidylinositol 3-kinase (PI3K)/AKT pathway activation, oncogenic transformation, and survival. Bypassing RTK reactivation of PI3K/AKT signaling represents a common resistance mechanism to EGFR-TKIs; SOS2KO reduced PI3K/AKT reactivation to limit osimertinib resistance. In a forced HGF/MET-driven bypass model, SOS2KO inhibited hepatocyte growth factor (HGF)-stimulated PI3K signaling to block HGF-driven osimertinib resistance. Using a long-term in situ resistance assay, most osimertinib-resistant cultures exhibited a hybrid epithelial/mesenchymal phenotype associated with reactivated RTK/AKT signaling. In contrast, RTK/AKT-dependent osimertinib resistance was markedly reduced by SOS2 deletion; the few SOS2KO cultures that became osimertinib resistant primarily underwent non-RTK-dependent epithelial-mesenchymal transition (EMT). Since bypassing RTK reactivation and/or tertiary EGFR mutations represent most osimertinib-resistant cancers, these data suggest that targeting proximal RTK signaling, here exemplified by SOS2 deletion, has the potential to delay the development osimertinib resistance and enhance overall clinical responses for patients with EGFR-mutated LUAD.

Research progress on lung cancer stem cells in epidermal growth factor receptor–tyrosine kinase inhibitor targeted therapy resistance in lung adenocarcinoma

Abstract Lung cancer is the leading cause of cancer-related deaths globally. In recent years, with the widespread use of genetic testing, epidermal growth factor receptor–tyrosine kinase inhibitor (EGFR-TKI)–targeted drugs have been efficacious to patients with lung adenocarcinoma exhibiting EGFR mutations. However, resistance to treatment is inevitable and eventually leads to tumor progression, recurrence, and reduction in the overall treatment efficacy. Lung cancer stem cells play a crucial role in the development of resistance toward EGFR-TKI–targeted therapy for lung adenocarcinoma. Lung cancer stem cells possess self-renewal, multilineage differentiation, and unlimited proliferation capabilities, which efficiently contribute to tumor formation and ultimately lead to tumor recurrence and metastasis. In this study, we evaluated the origin, markers, stemness index, relevant classic studies, resistance mechanisms, related signaling pathways, and strategies for reversing lung cancer stem cell resistance to EGFR-TKIs to provide new insights on delaying or reducing resistance and to improve the treatment efficacy of patients with EGFR-mutated lung adenocarcinoma in the future.

NEDD1 overexpression increases cell proliferation, tumor immune escape, and drug resistance in LUAD.

Background: Neural Precursor Cell Expressed Developmentally Down-Regulated Protein 1 (NEDD1) serves as a crucial factor in promoting cellular mitosis by directly facilitating wheel assembly and daughter centriole biogenesis at the lateral site of parent centrioles, ultimately driving centrosome replication. The amplification of centrosomes and the abnormal expression of centrosome-associated proteins contribute to the invasion and metastasis of non-small cell lung cancer cells. However, the specific mechanism by which NEDD1 contributes to the progression of lung adenocarcinoma (LUAD) remains unexplored. Therefore, the objective of this study is to uncover the role played by NEDD1 in LUAD. Methods: To verify the expression of NEDD1 in pan-carcinoma. The feasibility of NEDD1 as a prognostic marker for LUAD in TCGA and GEO databases was verified. Subsequently, Cox proportional hazard regression analysis was used to screen the prognostic factors of LUAD, so as to analyze the correlation between prognostic factors and NEDD1 expression. For another, NEDD1-related genes were screened for pathway enrichment analysis to verify their possible functions. In addition, the expression of NEDD1 in LUAD was verified by qPCR and IHC, then siRNA was used to construct NEDD1-knocked lung cancer cells for subsequent cytobehavioral experiments. Finally, the distribution of NEDD1 in single-cell samples was revealed, and then the correlation between its overexpression and LUAD immune escape and drug resistance was analyzed. Results: LUAD exhibits upregulation of NEDD1, which in turn promotes the proliferation, migration, invasion, and epithelial-mesenchymal transition of lung cancer cells, thereby contributing to a poor prognosis. Furthermore, the overexpression of NEDD1 is closely associated with immune escape and drug resistance in LUAD. Conclusion: NEDD1 serves as a reliable prognostic marker for LUAD, and its upregulation is associated with increased immune escape and drug resistance. Given these findings, NEDD1 holds potential as a novel therapeutic target for the treatment of LUAD.

MiR-125b reverses cisplatin resistance by regulating autophagy via targeting RORA/BNIP3L axis in lung adenocarcinoma.

The platinum-based chemotherapy is one of the most frequently used treatment protocols for lung adenocarcinoma (LUAD), and chemoresistance, however, usually results in treatment failure and limits its application in the clinic. It has been shown that microRNAs (miRNAs) play a significant role in tumor chemoresistance. In this study, miR-125b was identified as a specific cisplatin (DDP)-resistant gene in LUAD, as indicated by the bioinformatics analysis and the real-time quantitative PCR assay. The decreased serum level of miR-125b in LUAD patients was correlated with the poor treatment response rate and short survival time. MiR-125b decreased the A549/DDP proliferation, and the multiple drug resistance- and autophagy-related protein expression levels, which were all reversed by the inhibition of miR-125b. In addition, xenografts of human tumors in nude mice were suppressed by miR-125b, demonstrating that through autophagy regulation, miR-125b could reverse the DDP resistance in LUAD cells, both in vitro and in vivo. Further mechanistic studies indicated that miR-125b directly repressed the expression levels of RORA and its downstream BNIP3L, which in turn inhibited autophagy and reversed chemoresistance. Based on these findings, miR-125b in combination with DDP might be an effective treatment option to overcome DDP resistance in LUAD.

MicroRNA-486-5p Regulates DNA Damage Inhibition and Cisplatin Resistance in Lung Adenocarcinoma by Targeting AURKB.

Lung adenocarcinoma (LUAD) severely affects human health, and cisplatin (DDP) resistance is the main obstacle in LUAD treatment, the mechanism of which is unknown. Bioinformatics methods were utilized to predict expression and related pathways of AURKB in LUAD tissues, as well as the upstream regulated microRNAs. qRT-PCR assayed expression of AURKB and microRNA-486-5p. RIP and dual-luciferase experiments verified the binding and interaction between the two genes. CCK-8 was used to detect cell proliferation ability and IC50 values. Flow cytometry was utilized to assess the cell cycle. Comet assay and western blot tested DNA damage and γ-H2AX protein expression, respectively. In LUAD, AURKB was upregulated, but microRNA-486-5p was downregulated. The targeted relationship between the two was confirmed by RIP and dual-luciferase experiments. Cell experiments showed that AURKB knock-down inhibited cell proliferation, reduced IC50 values, induced cell cycle arrest, and caused DNA damage. The rescue experiment presented that high expression of microRNA-486-5p could weaken the impact of AURKB overexpression on LUAD cell behavior and DDP resistance. microRNA-486-5p regulated DNA damage to inhibit DDP resistance in LUAD by targeting AURKB, implying that microRNA-486-5p/AURKB axis may be a possible therapeutic target for DDP resistance in LUAD patients.

Exosomal lncCRLA is predictive for the evolvement and development of lung adenocarcinoma

Lung adenocarcinoma, the most common histological subtype of non-small cell lung cancer, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Our team uncovers that lncRNA related to chemotherapy resistance in lung adenocarcinoma (lncCRLA) is preferentially expressed in lung adenocarcinoma cells with the mesenchymal phenotype. lncCRLA can not enhance chemotherapy resistance in lung adenocarcinoma due to its binding to RIPK1 in exosomes, which is released into intercellular media and transferred by exosomes from mesenchymal-like to epithelial-like cells. However, plasmatic lncCRLA corresponding to tissue lncCRLA functions as a preferred biomarker to reflect the response to chemotherapy and disease progression of lung adenocarcinoma. Through single-cell sequencing, RNA-Mutect technique and spatial transcriptomics, a handful of hybrid EMT cells with elevated lncCRLA are characterized as the origin of lung adenocarcinoma, which are indiscriminated from hybrid EMT cells by the in-depth sequencing. Plasmatic lncCRLA is properly predictive for the preinvasive lesion of lung adenocarcinoma that would evolve to invasive lesion. That notion is confirmed by a brand-new transgenic mouse model in which EMT is tracked by Cre and Dre system. Dasatinib is potential to hinder the spontaneous progression from preinvasive to invasive lesion of lung adenocarcinoma. Together, plasmatic lncCRLA is defined as a brand-new circulating biomarker to predict the occurrence and evolvement of lung adenocarcinoma, a light for early detection of lung adenocarcinoma.

P1.08-04 Delivery of ATRA and Gefitinib by Polyphenylalanine Nanosystem to Overcome EGFR-TKI Resistance in Lung Adenocarcinoma

P1.08-04 Delivery of ATRA and Gefitinib by Polyphenylalanine Nanosystem to Overcome EGFR-TKI Resistance in Lung Adenocarcinoma

Circ_MACF1 targets miR-421 to upregulate FMO2 to suppress paclitaxel resistance and malignant cellular behaviors in lung adenocarcinoma.

Chemoresistance remains an enormous challenge in the treatment of lung adenocarcinoma (LADC). Circular RNAs (circRNAs) exhibit important regulation in tumor progression and chemoresistance. This research focused on exploring the regulatory function and mechanism of circ_MACF1 (has_circ_0011780) in paclitaxel (PTX) resistance in LADC. Circ_MACF1, miR-421 and flavin-containing monooxygenase 2 (FMO2) were determined by RT-qPCR. MTT was applied to detect IC50 of PTX. The proliferation analysis was performed using EdU and colony formation assay. Cell apoptosis and motility were examined using flow cytometry and transwell assay, respectively. Western blot was administered for protein detection. A dual-luciferase reporter assay was performed for confirming target interaction. PTX sensitivity in vivo was researched via xenograft tumor assay. Expression of circ_MACF1 was decreased in PTX-resistant LADC tissues and cells. Circ_MACF1 overexpression reduced chemoresistance, proliferation, motility and accelerated apoptosis in PTX-resistant LADC cells. Circ_MACF1 targeted miR-421 and miR-421 upregulation reverted circ_MACF1-evoked effects. FMO2 served as a downstream target of miR-421 and circ_MACF1 sponged miR-421 to elevate the expression of FMO2. MiR-421 enhanced PTX resistance and LADC progression via targeting FMO2. FMO2 knockdown enhanced IC50 of PTX and cell proliferation. In vivo, circ_MACF1 elevated PTX sensitivity of LADC by mediating miR-421/FMO2 axis. These findings elucidated that circ_MACF1 inhibited PTX resistance by absorbing miR-421 to upregulate FMO2 in LADC.