Human Non-small Cell Lung Cancer Cell Lines Research Articles

5-Azacytidine treatment inhibits the development of lung cancer models via epigenetic reprogramming and activation of cellular pathways with anti-tumor activity

Background and aims. Non-small cell lung cancer (NSCLC) treatment is challenged by late detection and limited therapeutic options. Aberrant DNA methylation, a common epigenetic alteration in NSCLC, offers new therapeutic avenues. This study aims to evaluate the combined effects of 5-Azacytidine (5- Aza), an epigenetic modifier, and ionizing radiation (IR) on NSCLC, exploring the underlying molecular mechanisms and therapeutic potential. Methods. In this study, we examined the effects of 5-Aza combined with IR in both in vitro and in vivo models of NSCLC. Five human NSCLC cell lines were treated with 5-Aza and IR. Cell viability, colony formation, wound healing, and transwell migration assays were performed to assess treatment effects. Microarray and qPCR analyses were conducted to identify gene expression changes. Additionally, subcutaneous and orthotopic xenograft models were used to evaluate the treatment’s efficacy in vivo. Results. Treatment with 5-Aza and IR resulted in significant reductions in cell viability, colony formation, and migration in NSCLC cell lines. Microarray analysis revealed significant changes in gene expression, including the upregulation of apoptosis-related genes and the downregulation of cell proliferation-related genes. In vivo studies demonstrated a notable reduction in tumor growth and metastasis in both subcutaneous and orthotopic NSCLC models following 5-Aza and IR treatment. Histological and bioluminescent imaging confirmed the therapeutic effects of the combined treatment. Conclusions. The combination of 5-Aza and IR shows promise as an effective treatment for NSCLC, enhancing apoptosis and reducing tumor growth through epigenetic modulation.

Low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by boosting MHC I expression in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a highly aggressive type of lung cancer with poor responses to traditional therapies such as surgery, radiotherapy, and chemotherapy. While immunotherapy has become an effective approach for treating multiple types of cancer, solid tumors frequently exhibit immune escape through various mechanisms, including downregulation of MHC I expression. However, whether the upregulation of MHC I expression can improve the immunotherapeutic effect on NSCLC remains unexplored. Suberoylanilide hydroxamic acid (SAHA) is a potent histone deacetylase (HDAC) inhibitor that has been applied clinically to treat lymphoma, but a high dose of SAHA kills tumor cells and normal cells without preference. Here, we report that low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by upregulating MHC I expression in NSCLC cells. Flow cytometric analysis, quantitative real-time PCR and western blot were used to analyze the expression of MHC I, STAT1 and Smad2/3 in both human and mouse NSCLC cell lines after SAHA treatment. The nuclear translocation of phosphorylated STAT1 and Smad2/3 was investigated by western blot and immunofluorescence staining. The mechanisms underlying STAT1 and Smad2/3 upregulation were analyzed through database searches and chromatin immunoprecipitation-qPCR. Finally, we assessed the antitumor effect of specific CD8+ T cells with SAHA treatment in vivo and in vitro. We showed that low-dose SAHA upregulated the expression of MHC I in NSCLC cell lines without affecting cell viability. We also provided evidence that high levels of MHC I induced by SAHA promoted the activation, proliferation, and cytotoxicity of specific CD8+ T cells in mouse models. Mechanistically, low-dose SAHA increased the levels of H3K9ac and H3K27ac in the promoters of the STAT1, Smad2 and Smad3 genes in NSCLC cells by inhibiting HDAC activity, resulting in elevated expression levels of STAT1, Smad2 and Smad3. The nuclear translocation of phosphorylated STAT1 and Smad2/3 markedly upregulated the expression of MHC I in NSCLC cells. Low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by boosting MHC I expression in NSCLC cells. Thus, we revealed a key mechanism of SAHA-mediated enhanced antitumor immunity, providing insights into a novel immunotherapy strategy for NSCLC.

Silencing Nrf2 in cisplatin resistant non-small cell lung cancer cells augments sensitivity towards EGFR inhibitor

Recently, non-small cell lung cancer (NSCLC) has been the prime concern of cancer clinicians due to its high mortality rate worldwide. Cisplatin, a platinum derivative, has been used as a therapeutic option for treating metastatic NSCLC for several years. However, acquired, or intrinsic drug resistance to Cisplatin is the major obstacle to the successful treatment outcome of patients. Dysregulation of Nrf2 (nuclear factor erythroid 2-related factor 2) and EGFR (epidermal growth factor receptor) signaling have been associated with cellular proliferation, cancer initiation, progression and confer drug resistance to several therapeutic agents including Cisplatin in various cancers. To dissect the molecular mechanism of EGFR activation in resistant cells, we developed Cisplatin-resistant (CisR) human NSCLC cell lines (A549 and NCIH460) with increasing doses of Cisplatin treatment over a 3-month period. CisR cells demonstrated increased proliferative capacity, clonogenic survivability and drug efflux activity compared to the untreated parental (PT) cells. These resistant cells also showed higher levels of Nrf2 and EGFR expression. Here, we found that Nrf2 upregulates both basal and inducible expression of EGFR in these CisR cells at the transcriptional level. Moreover, genetic inhibition of Nrf2 with siRNA in CisR cells showed increased sensitivity towards the EGFR tyrosine kinase inhibitor (TKIs), AG1478. Our study, therefore suggests the use of Nrf2 inhibitors in combinatorial therapy with EGFR TKIs for the treatment of resistant NSCLC.

Identification of Key Genes and Signaling Pathways in Entrectinibresistant Non-small Cell Lung Cancer Using Bioinformatic Analysis and Experimental Verification.

Entrectinib, a ROS1 inhibitor, is effective in patients with ROS1-positive non-small-cell lung cancer (NSCLC). However, entrectinib resistance remains a challenge worldwide. The biomarkers of entrectinib resistance and molecular mechanisms have not been clarified based on the Gene Expression Omnibus (GEO) database. The aim of this study is to identify key genes and signaling pathways involved in the development of entrectinib-resistant NSCLC through bioinformatics analysis and experimental validation. Differentially expressed genes (DEGs) were screened between entrectinib resistant and parental human NSCLC cell lines of the GSE214715 dataset, lung adenocarcinoma (LUAD) and non-tumor adjacent tissues of the GSE75037 dataset, and NSCLC and non-tumor adjacent tissues of the GSE18842 dataset. Functional enrichment analyses were performed, including Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Overlapped DEGs among those three datasets were identified using the Venn diagram package. The transcriptional levels of key genes were investigated using the University of ALabama at Birmingham CANcer data analysis Portal (UALCAN). The association between transcriptional levels of key genes and survival was analyzed using Kaplan-Meier Plotter (https://www.kmplot.com/analysis/). The correlations between hub genes and immune cell infiltration were investigated using the Tumor Immune Estimation Resource (TIMER) database. Specific signaling pathway enrichment analysis was performed using Gene Set Enrichment Analysis (GSEA) of LinkedOmics. Competitive endogenous RNA (ceRNA) networks, genome-wide association studies (GWAS), and drug sensitivity analyses of key genes were further investigated. The expression of ZEB2 was subsequently confirmed in both parental HCC78 cells and entrectinib-resistant HCC78 cells using real-time quantitative polymerase chain reaction (qRT-PCR). 708 DEGs were identified between entrectinib-resistant CUTO28 (CUTO28-ER) and parental CUTO28 cell lines in the GSE214715 dataset. One thousand three hundred and ninety-five DEGs were identified between entrectinib resistant (CUTO37-ER) and parental CUTO37 cell lines in the GSE214715 dataset. Eight hundred and forty-nine DEGs were identified between LUAD and non-tumor adjacent tissues in the GSE75037 dataset. Seven hundred and sevety-three DEGs were identified between NSCLC and non-tumor adjacent tissues in the GSE18842 dataset. Among these three datasets, seven overlapped DEGs were identified, including ZBED2, CHI3L2, CELF2, SEMA5A, ZEB2, S100A12, and PDK4. Among these seven overlapped DEGs, the expression levels of CHI3L2, ZEB2, and S100A12 were downregulated in those three datasets. The results of analysis using the UALCAN database showed that these three genes were significantly downregulated in LUAD and LUSC patients compared with the normal population. However, only the lower transcriptional level of ZEB2 was linked to worse survival in patients with lung cancer. GSEA analysis revealed that ZEB2 was significantly negatively correlated with nucleotide excision repair (NER) in LUAD, and homologous recombination (HR) and NER in LUSC, which were linked to drug resistance. A ceRNA network of THRB-AS1/ has-miR-1293/ ZEB2 in LUAD was established. We have identified core genes associated with non-small cell resistance to entrectinib, including CHI3L2, ZEB2, and S100A12. ZEB2 is a core gene associated with acquired resistance to entetinib in NSCLC.

MiR-3074-5p suppresses non-small cell lung cancer progression by targeting the YWHAZ/Hsp27 axis

Non-small cell lung cancer (NSCLC) accounts for more than 80% of lung cancer cases, and the 5-year survival rate of patients remains unsatisfactory. MicroRNAs (miRNAs) are small endogenous noncoding RNAs that are considered essential posttranscriptional regulators of tumorigenesis, including NSCLC. In this study, we aimed to investigate the biological role of miR-3074-5p in NSCLC cells and the underlying molecular mechanisms. We showed that miR-3074-5p expression was decreased in human NSCLC specimens and cell lines. Moreover, miR-3074-5p overexpression inhibited cell proliferation, migration and invasion and induced apoptosis and cell cycle arrest. In addition, miR-3074-5p overexpression not only suppressed tumor growth but also enhanced the antitumor effect of paclitaxel (PTX) on NSCLC cells in vitro and in vivo. A transcriptome sequencing assay revealed genes that were differentially expressed after miR-3074-5p overexpression, and among the genes whose expression levels were most significantly decreased, tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) was a target of miR-3074-5p. The regulatory effect of miR‐3074-5p on YWHAZ expression was verified by Western blotting and dual‐luciferase reporter assays. The inhibition of A549 cell growth, migration and invasion was reversed by YWHAZ overexpression. Furthermore, we showed that PTX stimulated the expression of the YWHAZ and Hsp27 proteins and promoted the phosphorylation of Hsp27 (at S15 and S78). YWHAZ was confirmed to interact with Hsp27 in A549 cells, and downregulating YWHAZ expression promoted the degradation of the Hsp27 protein. Taken together, these results suggest that the miR‐3074-5p/YWHAZ/Hsp27 axis may be a novel therapeutic target for NSCLC treatment.

DUSP1 Promotes Osimertinib Drug-Tolerant Persistence by Inhibiting MAPK/ERK Signaling in Non-small Cell Lung Cancer.

EGFR tyrosine kinase inhibitors (EGFR-TKIs) are the first-line treatment for EGFR-mutant non-small cell lung cancer (NSCLC) patients, which remarkably improve the clinical outcomes. However, drug resistance has greatly impaired the efficacy of EGFR-TKIs and contributes to cancer treatment failure. DUSP1, a negative regulator of MAPK signaling pathway, was discovered to mediate drug resistance in multiple types of cancers. Our study aimed to explore the role of DUSP1 in NSCLC cell resistance to osimertinib, a third-generation EGFR-TKI.Human NSCLC cell lines PC-9 and HCC827 were exposed to increasing concentrations of osimertinib for over 6 months to generate osimertinib resistant cells (PC-9-OR and HCC827-OR). The viabilities of osimertinib-resistant and parental sensitive NSCLC cells in response to osimertinib stimulation were detected by MTS assay and the IC50 values for osimertinib were obtained. The differentially expressed genes in osimertinib-resistant and sensitive NSCLC cells were identified by analyzing the GEO dataset GSE106765 using bioinformatic tools. DUSP1 expression was knocked down by using the short hairpin RNAs (shRNAs). Then, the effects of DUSP1 silencing on osimertinib-resistant and sensitive NSCLC cell resistance to osimertinib, viability, proliferation and apoptosis were assessed through loss-of-function experiments. The expression of key molecules (JNK, ERK, and p38 MAPK) in the MAPK signaling pathway was detected through western blotting analysis.DUSP1 was overexpressed in osimertinib-resistant NSCLC cells versus parental sensitive cells. DUSP1 silencing attenuated the resistance of NSCLC cells to osimertinib. DUSP1 silencing markedly inhibited osimertinib-resistant and sensitive NSCLC cell proliferation but enhanced cell apoptosis. Mechanically, DUSP1 knockdown increased phosphorylated-JNK, ERK, and p38 MAPK levels in NSCLC cells. Treatment with SB203580, the p38 MAPK inhibitor, reversed the effects of DUSP1 silencing on osimertinib-resistant NSCLC cell resistance to osimertinib, cell proliferation and apoptosis.DUSP1 downregulation restores the sensitivity of NSCLC cells to osimertinib via activating the MAPK signaling pathway.

Rs822336 binding to C/EBPβ and NFIC modulates induction of PD-L1 expression and predicts anti-PD-1/PD-L1 therapy in advanced NSCLC

Efficient predictive biomarkers are needed for immune checkpoint inhibitor (ICI)-based immunotherapy in non-small cell lung cancer (NSCLC). Testing the predictive value of single nucleotide polymorphisms (SNPs) in programmed cell death 1 (PD-1) or its ligand 1 (PD-L1) has shown contrasting results. Here, we aim to validate the predictive value of PD-L1 SNPs in advanced NSCLC patients treated with ICIs as well as to define the molecular mechanisms underlying the role of the identified SNP candidate. rs822336 efficiently predicted response to anti-PD-1/PD-L1 immunotherapy in advanced non-oncogene addicted NSCLC patients as compared to rs2282055 and rs4143815. rs822336 mapped to the promoter/enhancer region of PD-L1, differentially affecting the induction of PD-L1 expression in human NSCLC cell lines as well as their susceptibility to HLA class I antigen matched PBMCs incubated with anti-PD-1 monoclonal antibody nivolumab. The induction of PD-L1 expression by rs822336 was mediated by a competitive allele-specificity binding of two identified transcription factors: C/EBPβ and NFIC. As a result, silencing of C/EBPβ and NFIC differentially regulated the induction of PD-L1 expression in human NSCLC cell lines carrying different rs822336 genotypes. Analysis by binding microarray further validated the competitive allele-specificity binding of C/EBPβ and NFIC to PD-L1 promoter/enhancer region based on rs822336 genotype in human NSCLC cell lines. These findings have high clinical relevance since identify rs822336 and induction of PD-L1 expression as novel biomarkers for predicting anti-PD-1/PD-L1-based immunotherapy in advanced NSCLC patients.

“Crosstalk between non-coding RNAs and transcription factor LRF in non-small cell lung cancer”

Epigenetic approaches in direct correlation with assessment of critical genetic mutations in non-small cell lung cancer (NSCLC) are currently very intensive, as the epigenetic components underlying NSCLC development and progression have attained high recognition. In this level of research, established human NSCLC cell lines as well as experimental animals are widely used to detect novel biomarkers and pharmacological targets to treat NSCLC. The epigenetic background holds a great potential for the identification of epi-biomarkers for treatment response however, it is highly complex and requires precise definition as these phenomena are variable between NSCLC subtypes and systems origin.We engaged an in-depth characterization of non-coding (nc)RNAs prevalent in human KRAS-mutant NSCLC cell lines A549 and H460 and mouse KRAS-mutant NSCLC tissue by Next Generation Sequencing (NGS) and quantitative Real Time PCRs (qPCRs). Also, the transcription factor (TF) LRF, a known epigenetic silencer, was examined as a modulator of non-coding RNAs expression. Finally, interacting networks underlying epigenetic variations in NSCLC subtypes were created. Data derived from our study highlights the divergent epigenetic profiles of NSCLC of human and mouse origin, as well as the significant contribution of 12qf1: 109,709,060–109,747,960 mouse chromosomal region to micro-RNA upregulated species. Furthermore, the novel epigenetic miR-148b-3p/lncPVT1/ZBTB7A axis was identified, which differentiates human cell line of lung adenocarcinoma from large cell lung carcinoma, two characteristic NSCLC subtypes.The detailed recording of epigenetic events in NSCLC and combinational studies including networking between ncRNAs and TFs validate the identification of significant epigenetic features, prevailing in NSCLC subtypes and among experimental models. Our results enrich knowledge in the field and empower research on the epigenetic prognostic biomarkers of the disease progression, NSCLC subtypes discrimination and advancement to patient-tailored treatments.

Abstract 2531: rs822336 as a predictive biomarker for anti-PD-1/PD-L1 immunotherapy in advanced NSCLC: Unraveling molecular mechanisms

Abstract Efficient predictive biomarkers are needed for immune checkpoint inhibitor (ICI)-based immunotherapy in non-small-cell lung cancer (NSCLC). So far, testing the predictive value of single nucleotide polymorphisms (SNPs) in programmed cell death 1 (PD-1) or its ligand 1 (PD-L1) has shown contrasting results. Here, we aimed to validate the predictive value of PD-L1 SNPs in advanced NSCLC patients treated with ICIs as well as to define the molecular mechanisms underlying the role of identified SNP candidate. rs822336 SNP efficiently predicted response to anti-PD-1/PD-L1-based immunotherapy in advanced NSCLC patients as compared to rs2282055 and rs4143815 SNPs. rs822336 SNP mapped on promoter/enhancer region of PD-L1, differentially affecting the induction of PD-L1 expression in human NSCLC cell lines. The induction of PD-L1 expression by rs822336 SNP was predicted by allele-specificity binding of two identified transcription factors: C/EBPβ and NFIC. As a result, silencing of C/EBPβ and NFIC differentially modulated the induction of PD-L1 expression in human NSCLC cell lines carrying different rs822336 genotypes. In addition, binding microarray validated the allele- specificity binding of C/EBPβ and NFIC to PD-L1 promoter/enhancer region based on rs822336 genotype in human NSCLC cell lines. Lastly, the induction of PD-L1 expression by rs822336 genotype differentially affected the susceptibility to anti-PD-1 monoclonal antibody nivolumab of human NSCLC cell lines co-cultured with HLA class I antigen matched PBMC. These results have clinical relevance since identified rs822336 SNP and the induction of PD-L1 expression as novel biomarkers for predicting ICI-based immunotherapy in NSCLC patients. Citation Format: Giovanna Polcaro, Luigi Liguori, Valentina Manzo, Annalisa Chianese, Giuliana Donadio, Alessandro Caputo, Giosuè Scognamiglio, Federica Dell'Annunziata, Maddalena Langella, Graziamaria Corbi, Alessandro Ottaiano, Marco Cascella, Francesco Perri, Margot De Marco, Jessica Dal Col, Valentina Pagliara, Pio Zeppa, Amelia Filippelli, Gianluigi Franci, Fabrizio Dal Piaz, Valeria Conti, Stefano Pepe, Francesco Sabbatino. rs822336 as a predictive biomarker for anti-PD-1/PD-L1 immunotherapy in advanced NSCLC: Unraveling molecular mechanisms [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 2531.

Abstract 4084: Potent anti-tumor activity of ABN202 (anti-EGFR antibody-interferon-beta mutein) through direct cytotoxicity and indirect immune activation against non-small cell lung cancer, regardless of EGFR mutation status

Abstract Epidermal growth factor receptor (EGFR) is overexpressed or mutated in many patients with non-small cell lung cancer (NSCLC). Targeting EGFR mutation by tyrosine kinase inhibitors (TKIs) has significantly improved overall survival (OS) in patients with EGFR mutations. However, many patients experience tumor recurrence due to various resistance mechanisms. Therefore, there is an unmet medical need for new treatment strategies for patients with EGFR-positive NSCLC, regardless of EGFR mutation status. ABN202 is an antibody-cytokine fusion protein (ACFP) that serves as a platform technology compromising the IFN-β mutein (ABN102) fused to various antibodies for specific tumor targeting. In a previous study, we designed ABN202 (αEGFR) to comprise an EGFR targeting antibody (Cetuximab) and IFN-β mutein (ABN102) and we confirmed anti-cancer activities of ABN202 against EGFR-positive NSCLC. In this study, the direct cytotoxicity of ABN202 (αEGFR) was evaluated in human NSCLC cell lines with various driving mutations and EGFR expression levels. The indirect immune activation was tested in human peripheral blood mononuclear cells (PBMCs) and human IFNAR1/2 knock-in (KI) mice. The in vivo efficacy was evaluated in human NSCLC xenograft mouse models and human IFNAR1/2 KI mouse models. ABN202 (αEGFR) demonstrates potent anti-tumor activity through direct cytotoxicity and indirect immune activation in NSCLC, regardless of EGFR mutation status. Taken together, we suggest that ABN202 (αEGFR) is a promising drug candidate against NSCLC, regardless of EGFR mutation status. Citation Format: Hee Geon Park, Sung Hun Cho, Ha Yeon Park, Mi Gyoung Jo, Ji Hyun Park, Myeung Ryun Seo, Ji Hyun Kim, Sung Youl Hong, Kyoung Song, Chan Gyu Lee, Hae Min Jeong, Sae Hyung Lee, Na Young Kim, Jun Young Choi, Young Kee Shin. Potent anti-tumor activity of ABN202 (anti-EGFR antibody-interferon-beta mutein) through direct cytotoxicity and indirect immune activation against non-small cell lung cancer, regardless of EGFR mutation status [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 4084.

Abstract 4266: Evaluation of integrin alpha v beta 5 as a novel target for non-small cell lung cancer via tumor intrinsic and host immune regulation

Abstract Lung cancer is the leading cause of cancer related deaths worldwide, with the most prevalent subtype being non-small cell lung cancer (NSCLC). As only a subset of patients exhibits durable clinical responses to current treatments, including targeted therapy and immunotherapy, new treatment options are needed. Integrins (ITGs) are a diverse class of heterodimeric, transmembrane receptors that bind extracellularly to the extracellular matrix (ECM) and intracellularly to the cytoskeleton to integrate signals bi-directionally between the extracellular environment and cell interior. One of 18 α subunits is paired with one of 6 β subunits to create the 24 known αβ ITGs in mammals. ITGs are expressed at low levels in normal tissue and can be upregulated in cancer cells in response to stress signals in the tumor microenvironment (TME). Altered expression of ITGs is associated with enhanced cell proliferation, metastasis, and immune evasion. Targeting of the diverse ITG family members by inhibitors not specific to individual isoforms has obscured understanding of potentially distinct functions of each heterodimer. Through data mining of a genome wide CRISPR screening publicly available at the DepMap portal, we have identified a novel cancer dependency to ITG αvβ5 in approximately 40% of NSCLC cell lines. Using small molecule ITG αv inhibitors, we have mirrored sensitivity of NSCLC cell lines to their ITG αvβ5 CRISPR scores, suggesting that these inhibitors function specifically through ITG αvβ5 in cell lines. RNA sequencing analysis following αvβ5 inhibition in human NSCLC cell lines revealed downregulation of YAP and E2F1 target genes with alterations in gene ontologies associated with cell cycling and cell death in sensitive, but not resistant, lines. This is consistent with the known function of YAP driving gene transcription promoting cell proliferation and survival, and of E2F1 being implicated in regulating the proliferation and self-renewal of cancer stem cell (CSC). Additional changes to immune processes, specifically perturbations to interferon (IFN) pathways, were identified in response to ITG αvβ5 inhibition, suggesting that ITG αvβ5 may play a role in host anti-tumor immune responses. Pharmacological inhibition of ITG αvβ5 also led to a reduction of tumor growth in NSCLC murine models accompanied with increased CD8 T cell activation. These findings support ITG αvβ5 as a unique target of cancer dependency in NSCLC whose inhibition promotes anti-tumor responses through both tumor intrinsic and host immune regulatory mechanisms. Citation Format: Bitta P. Kahangi, William P. Crosson, Ji-Ann Lee, Camelia Dumitras, Tianhao Zhang, Ramin Salehi-Rad, Linh M. Tran, Michael Palazzolo, Dylan Conklin, Steven M. Dubinett, Bin Liu. Evaluation of integrin alpha v beta 5 as a novel target for non-small cell lung cancer via tumor intrinsic and host immune regulation [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 4266.

Abstract 2058: Compound library screening to identify modulators of alternative splicing in non-small cell lung cancer (NSCLC)

Abstract Alternative splicing is a molecular mechanism that allows a single gene to encode multiple proteins. It is a complex and highly controlled process used to regulate normal gene expression but is often dysregulated in cancer. Compounds that can modulate alternative splicing are currently being explored as a potential new class of therapeutic agent in cancer. This highlights the need for a deeper understanding of the splicing process, its regulation, and its impact. The discovery of novel and specific tool compounds that modulate splicing would therefore not only be beneficial in investigating the regulation and dysregulation of splicing in cancer but could also be exploited therapeutically. To identify novel regulators of splicing, we generated a cell-based split luciferase screening assay based on alternative splicing of MCL-1 (myeloid cell leukemia-1 protein) pre-mRNA. The MCL1 gene usually produces an mRNA encoding a ‘long’ variant (MCL1L) that is an anti-apoptotic protein often highly expressed in cancers. However, in some circumstances, for example following genetic knockdown of splicing factors, a pro-apoptotic ‘short’ variant (MCL1S) is expressed as a result of exon-skipping. Here we engineered the human NSCLC cell line NCI-H1299 to express a luminescent-tagged version of the MCL1S splice variant to monitor its induction upon spliceosome modulation. Using this engineered cell line, we screened an unannotated library of 12,000 compounds selected to have low molecular weights and favorable properties for cellular uptake. The screen had an average Z’ value of 0.89 over 45 microplates, indicating high assay robustness. Hits were identified as any compound with a luminescence of greater than the average + two standard deviations of the screening dataset. The compounds were validated by repetition in the screening assay, giving 34 candidate hits that were then triaged by qPCR assay to confirm splicing modulation of MCL1. One interesting hit was found to increase mRNA and cellular protein levels of MCL1S and induced altered splicing across the transcriptome that was distinct from the splicing profiles of a diverse panel of splicing modulators, including compounds targeting SF3B1, CLK, and RBM39. In addition, treatment with this hit compound resulted in accumulation of the splicing factor SC35 in cytoplasmic granules, an unusual phenotype not seen with known splicing modulators, that could explain the distinct splicing modulation we have observed. Deconvolution and further characterization of screening hits and potentially unique new mechanisms of action could improve current understanding of alternative splicing and its regulation in NSCLC. The discovery of novel compounds to expand our current toolset of splicing modulators will be key in building the foundation for future splicing targeted drug discovery. Citation Format: Rachel Cooley, Marissa V. Powers, Adam G. Bond, Patrizia Jensen, Gary Newton, Andrea Scarpino, Juliane Braun, Christina Esdar, Paul A. Clarke. Compound library screening to identify modulators of alternative splicing in non-small cell lung cancer (NSCLC) [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 2058.

Signal Transducer and Activator of Transcription 4-Induced Up-Regulated LINC01278 Enhances Proliferation and Invasion of Non-Small Cell Lung Cancer Cells via the MicroRNA-877-5p/Activating Transcription Factor 4 Axis.

The purpose of this study was to investigate the specific effects of signal transducer and activator of transcription 4 (STAT4)-induced long intergenic nonprotein coding RNA 1278 (LINC01278) on the growth of non-small cell lung cancer (NSCLC) cells involved in the microRNA (miR)-877-5p/activated transcription factor 4 (ATF4) axis. NSCLC tumor tissue and adjacent normal tissue were collected. Human normal lung epithelial cell BEAS-2B and human NSCLC cell lines (H1299, H1975, A549, H2228) were collected. The expression levels of STAT4, LINC01278, miR-877-5p, and ATF4 were detected. A549 cells were screened for subsequent experiments. The proliferation ability of cells was detected by colony formation experiment. Cell apoptosis was tested by flow cytometry. Scratch test and transwell assay were used to detect the migration and invasion ability of cells. Biological function of LINC01278 in NSCLC was confirmed by xenograft experiments. Low expression miR-877-5p and high expression of STAT4, LINC01278 and ATF4 were detected in NSCLC. Silenced LINC01278 in A549 cell depressed cell proliferation, migration and invasion, but facilitated cell apoptosis. LINC01278 was positively correlated with STAT4 and could directly bind to miR-877-5p. Upregulating miR-877-5p suppressed NSCLC cell progression, while downregulating miR-877-5p had the opposite effect. Upregulating miR-877-5p abrogated the effects of silenced LINC01278 on NSCLC cell progression. MiR-877-5p targeted ATF4. ATF4 upregulation could partly restore the carcinogenic effect of LINC01278 in vitro and in vivo. Our data supports that STAT4-induced upregulation of LINC01278 promotes NSCLC progression by modulating the miR-877-5p/ATF4 axis, suggesting a novel direction for NSCLC treatment.

Elevated expression of complement factor I in lung cancer cells associates with shorter survival–Potentially via non-canonical mechanism

While numerous membrane-bound complement inhibitors protect the body's cells from innate immunity's autoaggression, soluble inhibitors like complement factor I (FI) are rarely produced outside the liver. Previously, we reported the expression of FI in non-small cell lung cancer (NSCLC) cell lines. Now, we assessed the content of FI in cancer biopsies from lung cancer patients and associated the results with clinicopathological characteristics and clinical outcomes. Immunohistochemical staining intensity did not correlate with age, smoking status, tumor size, stage, differentiation grade, and T cell infiltrates, but was associated with progression-free survival (PFS), overall survival (OS) and disease-specific survival (DSS). Multivariate Cox analysis of low vs. high FI content revealed HR 0.55, 95 % CI 0.32-0.95, p=0.031 for PFS, HR 0.51, 95 % CI 0.25-1.02, p=0.055 for OS, and HR 0.32, 95 % CI 0.12-0.84, p=0.021 for DSS. Unfavorable prognosis might stem from the non-canonical role of FI, as the staining pattern did not correlate with C4d - the product of FI-supported degradation of active complement component C4b. To elucidate that, we engineered three human NSCLC cell lines naturally expressing FI with CRISPR/Cas9 technology, and compared the transcriptome of FI-deficient and FI-sufficient clones in each cell line. RNA sequencing revealed differentially expressed genes engaged in intracellular signaling pathways controlling proliferation, apoptosis, and responsiveness to growth factors. Moreover, in vitro colony-formation assays showed that FI-deficient cells formed smaller foci than FI-sufficient NSCLC cells, but their size increased when purified FI protein was added to the medium. We postulate that a non-canonical activity of FI influences cellular physiology and contributes to the poor prognosis of lung cancer patients.

Ginsenoside Rg5 induces NSCLC cell apoptosis and autophagy through PI3K/Akt/mTOR signaling pathway.

Ginsenoside Rg5 (Rg5) is a minor ginsenoside of ginseng and has a strong anti-tumor potential. This study focused on deciphering the function of Rg5 in non-small cell lung cancer (NSCLC) and investigating its related mechanism. After treating human NSCLC cell lines (H1650 and A549) and bronchial epithelial cells (BEAS-2B) with increasing concentration of Rg5, cell viability was examined using methyl thiazolyl tetrazolium (MTT) assay. NSCLC cell proliferation and apoptosis were evaluated by colony formation assay and flow cytometry, respectively. The levels of proteins associated with cell cycle progression, cell apoptosis, and autophagy as well as the key markers in the PI3K/Akt/mTOR pathway were measured using western blot. A xenograft nude mouse model was established to explore the function of Rg5 in vivo. NSCLC cell viability was dose- and time-dependently suppressed after Rg5 treatment. Rg5 restrained NSCLC cell proliferation by inducing G2/M phase arrest via regulation of cell cycle-related genes including p21, cyclin B1, and Cdc2. Additionally, Rg5 promoted caspase-dependent apoptosis in NSCLC cells by regulating the intrinsic mitochondrial signaling pathway. Rg5 induced autophagy via the regulation of autophagy-related proteins. The in vivo experiments revealed the inhibitory impact of Rg5 on xenograft growth. Rg5 also inactivated the PI3K/Akt/mTOR signaling pathway in NSCLC cells and mouse tumors. Rg5 induced autophagy and caspase-dependent apoptosis in NSCLC cells by inhibiting the PI3K/Akt/mTOR signaling pathway, suggesting that Rg5 might become a promising and novel anti-tumor agent for the clinical treatment of NSCLC patients.

Abstract B168: Identification of STX-241, a CNS-penetrant and mutant-selective EGFR inhibitor with activity on osimertinib-resistant C797x mutations

Abstract Background: EGFR mutations are well validated clinical targets in non-small cell lung cancer (NSCLC). Osimertinib, a highly-selective EGFR mutation-targeting covalent drug, is increasingly used in the first line setting for patients with NSCLC bearing EGFR L858R mutation or exon 19 deletions (ex19del). In a subset of these patients, co-occurring L858R/C797x or ex19del/C797x mutations (“double mutants”) are emerging as an on-target resistance mechanism, necessitating the need for new therapies, particularly in patients with CNS metastases. Materials and methods: STX-241 was tested across a panel of in vitro biochemical, cell signaling, and proliferation assays for potency against EGFR L858R and ex19del single mutants and the corresponding C797S double mutants. Additionally, STX-241 was tested for in vivo activity in mice bearing human NSCLC cell line xenografts NCI-H3255 (L858R) and PC-9 (ex19del), and in a PC-9-derived ex19del/C797S double mutant knock-in xenograft. Free CNS penetration (Kp,uu) was determined in non-tumor bearing mice. Osimertinib and gefitinib (an approved reversible EGFR inhibitor) were used as benchmark molecules across assays. Results: STX-241, an ATP-competitive reversible EGFR inhibitor representing novel chemical matter, demonstrated potent and selective inhibition of recombinant EGFR L858R/C797S mutant protein relative to wild-type, with increased mutant residence time relative to gefitinib. Potent (high picomolar to low nanomolar) inhibition of L858R, ex19del, L858R/C797S, and ex19del/C797S mutants was observed in proliferation assays using engineered Ba/F3 and human NSCLC cell lines. STX-241 demonstrated >150x selectivity for all tested EGFR mutants relative to wild-type EGFR in engineered Ba/F3 cells and human cancer cells. In these assays, STX-241 selectivity exceeded that of the benchmark reversible EGFR inhibitor gefitinib. Strong potency and double mutant selectivity was also observed for STX-241 in pharmacodynamic assays measuring EGFR pathway activation (pEGFR). STX-241 was well tolerated at doses of 15 mg/kg BID or 50 mg/kg QD in mice, where regression of EGFR exon 19 or 21 mutant NSCLC xenografts was observed, concomitant with EGFR pathway suppression. Notably, using an isogenic pair of PC-9 (EGFR ex19del) NSCLC xenografts that differ only by the presence of a C797S mutation, STX-241 demonstrates no drop off in antitumor activity in the presence of C797S. In mouse pharmacokinetic studies measuring free CNS penetration, Kp,uu measurements were comparable to Osimertinib, run in parallel as a benchmark. Conclusions: STX-241 demonstrates strong potency and selectivity against EGFR L858R/C797S and ex19del/C797S double mutants, as well as robust CNS penetrance. These data warrant further exploration of this potential best-in-class inhibitor in the clinic for patients progressing on Osimertinib via C797x mutation. Citation Format: Raymond A Pagliarini, Benjamin C Milgram, Deanna R Borrelli, Erin O'Hearn, Michael R. Huff, Brendon Ladd, Natasja Brooijmans, Weixue Wang, Petr Kuzmic, Angel Guzman-Perez, Darrin D Stuart. Identification of STX-241, a CNS-penetrant and mutant-selective EGFR inhibitor with activity on osimertinib-resistant C797x mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B168.

Antitumor activity of pegylated human interferon β as monotherapy or in combination with immune checkpoint inhibitors via tumor growth inhibition and dendritic cell activation

Type I interferons (IFN), especially human IFN alpha (IFNα), have been utilized for antitumor therapy for decades. Human interferon beta (IFNβ) is rarely used for cancer treatment, despite advantages over IFNα in biological activities such as tumor growth inhibition and dendritic cell (DC) activation. The utilization of pegylated human IFNβ (PEG-IFNβ), as monotherapy or in combination with immune checkpoint inhibitors (ICIs) was evaluated in this study through in vivo efficacy studies in syngeneic mouse melanoma, non-small cell lung cancer (NSCLC), and colon adenocarcinoma (COAD) models resistant to immune checkpoint inhibitors (ICIs). In vitro comparative study of PEG-IFNβ and pegylated IFNα-2b was performed in terms of tumor growth inhibition against human melanoma, NSCLC and COAD cell lines and activation of human monocyte-derived DCs (MoDCs). Our data demonstrate that the in vivo antitumor effects of PEG-IFNβ are partially attributable to tumor growth-inhibitory effects and DC-activating activities, superior to pegylated IFNα-2b. Our findings suggest that utilizing PEG-IFNβ as an antitumor therapy can enhance the therapeutic effect of ICIs in ICI-resistant tumors by directly inhibiting tumor growth and induction of DC maturation.

SERPINE1 and SERPINB7 as potential biomarkers for intravenous vitamin C treatment in non-small-cell lung cancer

High dose intravenous vitamin C (IVC) has been proposed as a pro-oxidant anticancer agent. However, there is a lack of biomarkers that are specific for this treatment. Here, we explored profiles of gene expression responding to IVC treatment in non-small cell lung cancer (NSCLC) cells as an effort for potential biomarker discovery. Genome-wide RNA-seq was performed in human NSCLC cell lines treated with pharmacological concentrations of vitamin C(VitC) for differential expression of genes. The identified genes were analyzed for correlations with patient prognosis using data from the Kaplan-Meier Plotter and the Human Protein Atlas databases. Further, tumor samples from a retrospective study of 153 NSCLC patients were analyzed with immunohistochemistry for expression of targeted genes, and patient prognosis was correlated to these genes. Two genes, namely SERPINE1 and SERPINB7 were found to be downregulated in NSCLC cells following VitC treatment. Combined patient data from the cohort analysis and online databases revealed that these 2 genes presented an unfavorable prognostic prediction of overall survival (OS) in NSCLC patients receiving standard of care. However, high expression level of these 2 genes were associated with prolonged OS in NSCLC patients receiving IVC in addition to standard of care. These data revealed that SERPINE1 and SERPINB7 have the potential to serve as predictive factors indicating favorable responses to IVC treatment in patients with NSCLC. Further validations are warranted.

FOXA1 prolongs S phase and promotes cancer progression in non-small cell lung cancer through upregulation of CDC5L and activation of the ERK1/2 and JAK2 pathways.

Non-small cell lung cancer (NSCLC) causes high mortality worldwide; however, its molecular pathways have not been fully investigated. The relationship between FOXA1 and CDC5L as well as their roles in NSCLC have not been comprehensively studied. Clinical tissues were collected from 78 NSCLC patients for clinical studies. The BEAS-2B human normal lung epithelial cell line and the A549, Calu-3, H526 and H2170 human NSCLC cell lines were used for in vitro studies. sh-FOXA1 and oe-CDC5L constructs were used to generate knockdown and overexpression models, respectively. The CCK-8 assay was used to analyze cell viability. The cell cycle and apoptosis were evaluated by flow cytometry analysis. The relationship between FOXA1 and CDC5L was demonstrated using dual-luciferase and ChIP assays. Gene levels were examined via immunohistochemistry, qRT-PCR and western blot analysis. FOXA1 levels were increased in NSCLC clinical tissues and cell lines. Depletion of FOXA1 increased the apoptosis rate and increased the proportion of cells in G2/M phase. In addition, we demonstrated that FOXA1 was directly bound to the promoter of CDC5L and that depletion of FOXA1 inhibited CDC5L expression. Overexpression of CDC5L induced ERK1/2 phosphorylation, induced JAK2 phosphorylation, inhibited cell apoptosis, prolonged S phase, and significantly reversed the effects of FOXA1 knockdown on the progression of NSCLC. The present study demonstrated that FOXA1 prolongs S phase and promotes NSCLC progression through upregulation of CDC5L and activation of the ERK1/2 and JAK2 pathways.

Skp2-mediated MLKL degradation confers cisplatin-resistant in non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is the most prevalent type of cancer and the leading cause of cancer-related death. Chemotherapeutic resistance is a major obstacle in treating NSCLC patients. Here, we discovered that the E3 ligase Skp2 is overexpressed, accompanied by the downregulation of necroptosis-related regulator MLKL in human NSCLC tissues and cell lines. Knockdown of Skp2 inhibited viability, anchorage-independent growth, and in vivo tumor development of NSCLC cells. We also found that the Skp2 protein is negatively correlated with MLKL in NSCLC tissues. Moreover, Skp2 is increased and accompanied by an upregulation of MLKL ubiquitination and degradation in cisplatin-resistant NSCLC cells. Accordingly, inhibition of Skp2 partially restores MLKL and sensitizes NSCLC cells to cisplatin in vitro and in vivo. Mechanistically, Skp2 interacts and promotes ubiquitination-mediated degradation of MLKL in cisplatin-resistant NSCLC cells. Our results provide evidence of an Skp2-dependent mechanism regulating MLKL degradation and cisplatin resistance, suggesting that targeting Skp2-ubiquitinated MLKL degradation may overcome NSCLC chemoresistance.