Phenotype Of Lung Cancer Research Articles

P1.06C.04 Low-Level Deletion of Chromosome 19p Genes May Be Sufficient to Drive Histology-Dependent Phenotypes in Lung Cancer

P1.06C.04 Low-Level Deletion of Chromosome 19p Genes May Be Sufficient to Drive Histology-Dependent Phenotypes in Lung Cancer

UCHL1 Overexpression Is Related to the Aggressive Phenotype of Non-small Cell Lung Cancer.

Ubiquitin C-terminal hydrolase L1 (UCHL1), which encodes thiol protease that hydrolyzes a peptide bond at the C-terminal glycine residue of ubiquitin, regulates cell differentiation, proliferation, transcriptional regulation, and numerous other biological processes and may be involved in lung cancer progression. UCHL1 is mainly expressed in the brain and plays a tumor-promoting role in a few cancer types; however, there are limited reports regarding its role in lung cancer. Single-cell RNA (scRNA) sequencing using 10X chromium v3 was performed on a paired normal-appearing and tumor tissue from surgical specimens of a patient who showed unusually rapid progression. To validate clinical implication of the identified biomarkers, immunohistochemical (IHC) analysis was performed on 48 non-small cell lung cancer (NSCLC) tissue specimens, and the correlation with clinical parameters was evaluated. We identified 500 genes overexpressed in tumor tissue compared to those in normal tissue. Among them, UCHL1, brain expressed X-linked 3 (BEX3), and midkine (MDK), which are associated with tumor growth and progression, exhibited a 1.5-fold increase in expression compared to that in normal tissue. IHC analysis of NSCLC tissues showed that only UCHL1 was specifically overexpressed. Additionally, in 48 NSCLC specimens, UCHL1 was specifically upregulated in the cytoplasm and nuclear membrane of tumor cells. Multivariable logistic analysis identified several factors, including smoking, tumor size, and high-grade dysplasia, to be typically associated with UCHL1 overexpression. Survival analyses using The Cancer Genome Atlas (TCGA) datasets revealed that UCHL1 overexpression is substantially associated with poor survival outcomes. Furthermore, a strong association was observed between UCHL1 expression and the clinicopathological features of patients with NSCLC. UCHL1 overexpression was associated with smoking, tumor size, and high-grade dysplasia, which are typically associated with a poor prognosis and survival outcome. These findings suggest that UCHL1 may serve as an effective biomarker of NSCLC.

Identification of zinc finger MIZ-type containing 2 as an oncoprotein enhancing NAD-dependent protein deacetylase sirtuin-1 deacetylase activity to regulate Wnt and Hippo pathways in non-small-cell lung cancer

BackgroundZinc finger MIZ-type containing 2 (ZMIZ2) can function as a coactivator and participate in the progression of certain malignant tumors; however, its expression and underlying molecular mechanism in non-small-cell lung cancer (NSCLC) remains unknown. In this study, we aim to analyze the expression of ZMIZ2 and its tumorigenic function in NSCLC, identifying its related factors.MethodsZMIZ2 expression in NSCLC tissue samples and cell lines was examined using immunohistochemistry and western blotting; its biological role was investigated using in vivo and in vitro assays. The association between ZMIZ2 and NAD-dependent protein deacetylase sirtuin-1 (SIRT1) was demonstrated using mass spectrometry and immunoprecipitation experiments. Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG)-based enrichment analysis, luciferase reporter assay, and real-time quantitative polymerase chain reaction (RT–qPCR) were conducted to verify the impact of ZMIZ2–SIRT1 combination on Hippo/Wnt pathways.ResultsZMIZ2 was highly expressed in NSCLC and positively associated with advanced pTNM staging, lymph node metastasis, and poor overall survival. Functional experiments revealed that ZMIZ2 promotes the proliferation, migration, and invasiveness of lung cancer cells—establishing its role as a promoter of oncogenes. Molecular mechanism studies identified SIRT1 as an assisted key factor interacting with ZMIZ2. KEGG enrichment analysis revealed that ZMIZ2 is closely related to Wnt/Hippo pathways; ZMIZ2–SIRT1 interaction enhanced SIRT1 deacetylase activity. Direct downregulation of intranuclear β-catenin and yes-associated protein (YAP) acetylation levels occurred independently of upstream proteins in Wnt/Hippo pathways; transcriptional activities of β-catenin-transcription factor 4 (TCF4) and YAP–TEA domain family transcription factors (TEADs) were amplified.ConclusionsZMIZ2 promotes the malignant phenotype of lung cancer by regulating Wnt/Hippo pathways through SIRT1, providing an experimental basis for discovering novel biomarkers and developing tumor-targeted drugs.Graphical

DNMT3A loss drives a HIF-1-dependent synthetic lethality to HDAC6 inhibition in non-small cell lung cancer

DNMT3A encodes a DNA methyltransferase involved in development, cell differentiation, and gene transcription, which is mutated and aberrant-expressed in cancers. Here, we revealed that loss of DNMT3A promotes malignant phenotypes in lung cancer. Based on the epigenetic inhibitor library synthetic lethal screening, we found that small-molecule HDAC6 inhibitors selectively killed DNMT3A-defective NSCLC cells. Knockdown of HDAC6 by siRNAs reduced cell growth and induced apoptosis in DNMT3A-defective NSCLC cells. However, sensitive cells became resistant when DNMT3A was rescued. Furthermore, the selectivity to HDAC6 inhibition was recapitulated in mice, where an HDAC6 inhibitor retarded tumor growth established from DNMT3A-defective but not DNMT3A parental NSCLC cells. Mechanistically, DNMT3A loss resulted in the upregulation of HDAC6 through decreasing its promoter CpG methylation and enhancing transcription factor RUNX1 binding. Notably, our results indicated that HIF-1 pathway was activated in DNMT3A-defective cells whereas inactivated by HDAC6 inhibition. Knockout of HIF-1 contributed to the elimination of synthetic lethality between DNMT3A and HDAC6. Interestingly, HIF-1 pathway inhibitors could mimic the selective efficacy of HDAC6 inhibition in DNMT3A-defective cells. These results demonstrated HDAC6 as a HIF-1-dependent vulnerability of DNMT3A-defective cancers. Together, our findings identify HDAC6 as a potential HIF-1-dependent therapeutic target for the treatment of DNMT3A-defective cancers like NSCLC.

1309P A genomic scar based signature (HRDsig) and biallelic BRCA alterations identify a homologous recombination deficiency (HRD) phenotype of non-small cell lung cancer (NSCLC) potentially actionable to the PARP inhibitor rucaparib: Post-hoc analysis of lung-MAP substudy S1900A

1309P A genomic scar based signature (HRDsig) and biallelic BRCA alterations identify a homologous recombination deficiency (HRD) phenotype of non-small cell lung cancer (NSCLC) potentially actionable to the PARP inhibitor rucaparib: Post-hoc analysis of lung-MAP substudy S1900A

WNT5B promotes the malignant phenotype of non-small cell lung cancer via the FZD3–DVL3–RAC1–PCP–JNK pathway

The WNT5B ligand regulates the non-canonical wingless-related integration site (WNT)–planar cell polarity (PCP) pathway. However, the detailed mechanism underlying the activity of WNT5B in the WNT–PCP pathway in non-small cell lung cancer (NSCLC) is unclear. In this study, we assessed the clinicopathological significance of WNT5B expression in NSCLC specimens. WNT5B-overexpression and -knockdown NSCLC cell lines were generated in vivo and in vitro, respectively. WNT5B overexpression in NSCLC specimens correlates with advanced tumor node metastasis (TNM) stage, lymph node metastasis, and poor prognosis in patients with NSCLC. Additionally, WNT5B promotes the malignant phenotype of NSCLC cells in vivo and in vitro. Interactions were identified among WNT5B, frizzled3 (FZD3), and disheveled3 (DVL3) in NSCLC cells, leading to the activation of WNT–PCP signaling. The FZD3 receptor initiates DVL3 recruitment to the membrane for phosphorylation in a WNT5B ligand-dependent manner and activates c-Jun N-terminal kinase (JNK) signaling via the small GTPase RAC1. Furthermore, the deletion of the DEP domain of DVL3 abrogated these effects. Overall, we demonstrated a novel signal transduction pathway in which WNT5B recruits DVL3 to the membrane via its DEP domain through interaction with FZD3 to promote RAC1–PCP–JNK signaling, providing a potential target for clinical intervention in NSCLC treatment.

PGRMC1 promotes NSCLC stemness phenotypes by disrupting TRIM56-mediated ubiquitination of AHR

Cancer stem cells (CSCs) are responsible for tumor chemoresistance, and the aryl hydrocarbon receptor (AHR) is indispensable for maintaining CSC characteristics. Here, we aimed to investigate how the interaction between progesterone receptor membrane component 1 (PGRMC1) and AHR contributes to the maintenance of CSC phenotypes in non-small cell lung cancer (NSCLC). Clinical data and tissue microarray analyses indicated that patients with elevated PGRMC1 expression had poorer prognoses. Moreover, PGRMC1 overexpression enhanced CSC phenotypes and chemotherapy resistance in vitro and in vivo by modulating AHR ubiquitination. We then determined the specific interaction sites between PGRMC1 and AHR. Mass spectrometry screening identified tripartite motif containing 56 (TRIM56) as the E3 ligase targeting AHR. Notably, PGRMC1 overexpression inhibited the interaction between TRIM56 and AHR. Overall, our study revealed a regulatory mechanism that involves PGRMC1, AHR, and TRIM56, providing insights for developing CSC-targeting strategies in NSCLC treatment.

The effect of <i>NOTCH1</i> knockdown on the phenotype of human lung and colon cancer stem cells

Introduction. Lung and colorectal cancers are the most common cancer types, characterized by a poor prognosis. Tumor progression is also caused by the aberrant activity of intercellular signaling pathways, which can arise due to mutations in genes encoding their components. In particular, the oncogenic role of NOTCH1 receptor of Notch signaling pathway has been proven for various cancer types, including lung and colorectal cancers. In this research, we delved deeper into the importance of NOTCH1 receptor expression for the progression of these malignancies. Aim. To investigate the importance of NOTCH1 expression in maintaining the cancer stem cell (CSC) pool and phenotype of human lung and colon cancers. Materials and methods. Experiments were performed on previously obtained NOTCH1 knockdown cell lines of human lung A549 and colon HCT116 carcinomas. First of all, we studied the effect of NOTCH1 knockdown on the metastatic ability of A549 cells and the tumorigenicity of A549 and HCT116 cells when injected to immunodeficient BALB/c nu/nu mice. Next, we carried out in vitro tests to determine CSC pool and phenotype in tumor cell culture: cytofluorimetric analysis of ABC-transporters activity to exclude dye to the external environment and analysis of colony formation in a semi-liquid medium. In conclusion, we assessed the proportion of cells in the culture producing the CSC marker – CD133 using flow cytometry and the expression level of some genes associated with CSC phenotype (NANOG, POU5F1, SOX2) using real-time polymerase chain reaction. Results. NOTCH1 knockdown decreased the number of experimental animals with metastases, the number of formed metastatic foci and increased in the minimum cell inoculation dose. The activity of ABC-transporters, the ability for unattached growth, the proportion of CD133-positive cells in culture, and the expression of genes associated with maintaining of CSC pool and phenotype decreased under NOTCH1 knockdown in both cell lines. Conclusion. NOTCH1 expression is important for maintaining CSC pool and phenotype of human lung and colon carcinomas. The obtained data may be valuable in the development of anticancer therapies.

Multiplex Intraoperative Rapid Immunohistochemistry with Noncontact Antibody Mixing for Distinguishing the Histologic Phenotype of Lung Cancer.

Determining a surgical strategy for early-stage lung cancer requires an accurate histologic diagnosis. Immunohistochemistry (IHC) enables reliable diagnosis of histological types but requires more time and more tumor tissue slides than hematoxylin and eosin staining. We aimed to assess the clinical validity of a new rapid multiplex IHC technique utilizing alternating current (AC) mixing for intraoperative lung cancer diagnosis. Forty-three patients who underwent radical resection of lung cancers were enrolled in a retrospective observational study. Frozen sections were prepared from lung tumor samples, and rapid IHC employing AC mixing was implemented alongside a multiplex IHC protocol targeting thyroid transcription factor-1 + cytokeratin 5, desmoglein 3 + Napsin A, and p63 + tripartite motif containing 29. We then evaluated the concordance between intraoperative diagnoses derived from rapid multiplex IHC and final pathology. The concordance rate between the pathological diagnosis made with added rapid multiplex IHC and the final pathology was 93.0% (Cohen's 𝜅 coefficient = 0.860 and 95% CI: 0.727-0.993). When considering only adenocarcinoma and squamous cell carcinoma, the diagnoses were in agreement for all cases. We suggest rapid multiplex IHC as a promising tool for determining surgical strategies for lung tumors.

Mutant TP53 promotes invasion of lung cancer cells by regulating desmoglein 3

PurposeTargeted therapies have markedly improved the prognosis of lung cancer patients; nevertheless, challenges persist, including limited beneficiary populations and the emergence of drug resistance. This study investigates the molecular mechanisms of mutant TP53 in lung cancer, aiming to contribute to novel strategies for targeted therapy.MethodsThe TCGA database was employed to delineate the mutational landscape of TP53 in lung cancer patients. Differential gene expression between TP53-mutant and wild-type patients was analyzed, followed by functional enrichment. DSG3 protein expression in lung cancer patients was assessed using IHC, and its impact on prognosis was analyzed in the TCGA database. The influence of TP53 on the downstream gene DSG3 was investigated using qPCR, ChIP-qPCR, and luciferase reporter gene assays. Protein enrichment in the DSG3 promoter region was examined through IP-MS, and the regulatory role of the HIF1-α/TP53 complex on DSG3 was explored using Co-IP, luciferase assays, and ChIP-qPCR. Molecular interactions between TP53 (R273H) and HIF1-α were detected through immunoprecipitation and molecular docking. The effects and mechanisms of DSG3 on lung cancer phenotypes were assessed through WB, transwell, and wound healing assays.ResultsTP53 mutations were present in 47.44% of patients, predominantly as missense mutations. DSG3 exhibited high expression in TP53-mutant lung cancer patients, and this elevated expression correlated with a poorer prognosis. TP53 interference led to a reduction in DSG3 mRNA expression, with TP53 mutant P53 enriching at the P2 site of the DSG3 promoter region, a recruitment facilitated by HIF1-α. The DBD region of TP53 (R273H) demonstrated interaction with HIF1-α. DSG3, activated through Ezrin phosphorylation, played a role in promoting invasion and metastasis.ConclusionsMutant TP53 facilitates lung cancer cell invasion by modulating desmoglein 3.Graphical abstractThe regulation of TP53 on DSG3 in lung cancer cell

LINC01133 contributes to the malignant phenotypes of non-small cell lung cancer by targeting miR-30b-5p/FOXA1 pathway.

This study aimed to explore the mechanism of action of LINC01133 in non-small cell lung cancer. LINC01133 expression in NSCLC patient tissues and cells was detected by qRT-PCR. After transfecting siRNA-LINC01133 in NSCLC cells, the proliferation and invasive migration ability of the cells were assessed via CCK-8 and Transwell assay, respectively. The sublocalization of LINC01133 in NSCLC cells was analyzed by bioinformatics prediction and nucleoplasm separation assay and RNA-FISH assay. Analysis of the binding relationship between LINC01133, FOXA1 and miR-30b-5p was all through bioinformatics website analysis, dual-luciferase reporter and RNA Pulldown assay. Functional rescue experiments confirmed the character of miR-30b-5p and FOXA1 in LINC01133 regulating the NSCLC cells biological behavior. LINC01133 high expressions were found in NSCLC tissues and cells. siRNA-LINC01133 treatment inhibited NSCLC cells malignant behavior. Mechanistically: LINC01133 promoted FOXA1 expression through adsorption binding of miR-30b-5p. Knocking down miR-30b-5p expression or up-regulating FOXA1 expression was able to reverse siRNA-LINC01133 inhibitory effect of tumor cell malignant behavior. LINC01133 promoted FOX1 expression by competitively binding miR-30b-5p, which attenuated the targeting inhibitory effect of miR-30b-5p on FOXA1 and ultimately promoted proliferation and invasive migration of NSCLC cells.

Abstract SY35-02: Spatial mapping of mitochondrial networks in lung cancer

Abstract Mitochondria are critical to the governance of metabolism and bioenergetics in cancer cells. The mitochondria form highly organized networks, in which their outer and inner membrane structures define their bioenergetic capacity. However, in vivo studies delineating the relationship between the structural organization of mitochondrial networks and their bioenergetic activity have been limited. Here we present an in vivo structural and functional profiling of mitochondrial networks and bioenergetic phenotypes in non-small cell lung cancer (NSCLC) using an integrated platform comprised of positron emission tomography (PET) imaging, respirometry and 3-dimensional scanning block-face electron microscopy (3D SBEM). Interestingly, the diverse bioenergetic phenotypes and metabolic dependencies we identified in NSCLC tumors align with distinct structural organization of mitochondrial networks present. Further, we discovered that mitochondrial networks are organized into distinct compartments within tumor cells. In tumors with high rates of oxidative phosphorylation (OXPHOSHI) and fatty acid oxidation we identified peri-droplet mitochondrial networks wherein mitochondria contact and surround lipid droplets. In contrast, we discovered that in tumors with low rates of OXPHOS (OXPHOSLO), high glucose flux regulated i) peri-nuclear localization of mitochondria, ii) structural remodeling of cristae and iii) mitochondrial respiratory capacity. Our findings suggest that in NSCLC, mitochondrial networks are compartmentalized into distinct subpopulations that govern the bioenergetic capacity of tumors. Structure-and-function studies defining the relationship between mitochondrial architecture and metabolic dependencies may hold promise as strategies to profile metabolic liabilities unique to lung cancer subtypes. We anticipate that coupling PET imaging with 3D SBEM will have dynamic applications beyond that of lung cancer and enrich our understanding of how mitochondrial bioenergetics impact human disease. Citation Format: David B. Shackelford. Spatial mapping of mitochondrial networks in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr SY35-02.

High risk of lung cancer in surfactant-related gene variant carriers.

Several rare surfactant-related gene (SRG) variants associated with interstitial lung disease are suspected to be associated with lung cancer, but data are missing. We aimed to study the epidemiology and phenotype of lung cancer in an international cohort of SRG variant carriers. We conducted a cross-sectional study of all adults with SRG variants in the OrphaLung network and compared lung cancer risk with telomere-related gene (TRG) variant carriers. We identified 99 SRG adult variant carriers (SFTPA1 (n=18), SFTPA2 (n=31), SFTPC (n=24), ABCA3 (n=14) and NKX2-1 (n=12)), including 20 (20.2%) with lung cancer (SFTPA1 (n=7), SFTPA2 (n=8), SFTPC (n=3), NKX2-1 (n=2) and ABCA3 (n=0)). Among SRG variant carriers, the odds of lung cancer was associated with age (OR 1.04, 95% CI 1.01-1.08), smoking (OR 20.7, 95% CI 6.60-76.2) and SFTPA1/SFTPA2 variants (OR 3.97, 95% CI 1.39-13.2). Adenocarcinoma was the only histological type reported, with programmed death ligand-1 expression ≥1% in tumour cells in three samples. Cancer staging was localised (I/II) in eight (40%) individuals, locally advanced (III) in two (10%) and metastatic (IV) in 10 (50%). We found no somatic variant eligible for targeted therapy. Seven cancers were surgically removed, 10 received systemic therapy, and three received the best supportive care according to their stage and performance status. The median overall survival was 24 months, with stage I/II cancers showing better survival. We identified 233 TRG variant carriers. The comparative risk (subdistribution hazard ratio) for lung cancer in SRG patients versus TRG patients was 18.1 (95% CI 7.1-44.7). The high risk of lung cancer among SRG variant carriers suggests specific screening and diagnostic and therapeutic challenges. The benefit of regular computed tomography scan follow-up should be evaluated.

Abstract 6775: 3D culture aggregation morphology depends on cell phenotype and gene expression profiles in lung cancer

Abstract Background: Three-dimensional (3D) cell culture allows for the reproduction of tissue structure and function in a state more akin to the in vivo environment compared to two-dimensional (2D) cell culture. It is established that 3D culture more faithfully replicates cell morphology, differentiation, proliferation, gene and protein expression, and responsiveness to stimulation, as well as drug metabolism. Focusing on the observation that lung cancer cell lines exhibit different clustering morphologies in 3D cell culture, we conducted a comparative study on the relationship between these clustering morphologies and the characteristics of the lung cancer cell lines. Methods: We cultured 30 lung cancer cell lines using 3D culture plate, and classified the types of cell clustering morphologies formed. We evaluated the molecular and cellular biology characteristics of all cell lines. Additionally, comprehensive gene expression analysis using RNA sequencing was performed on the 30 3D-cultured cell samples, and the characteristics of gene expression between different clustering types were compared. Results: The 3D culture aggregation morphology of 30 lung cancer cell lines were classified into three types (monolayer sheet, NOS, spheroid). Monolayer sheet-type cells exhibited higher proliferation, migration, and invasion capabilities compared to spheroid-type cells. In the transcriptomic bioinformatics analysis of the acquired gene expression data, GSEA analysis using Hallmark gene sets showed that the enrichment of epithelial-mesenchymal transition (EMT) and cancer metastasis-related genes in the monolayer type cells significantly compared to the spheroid type cells. Conversely, cell adhesion and intercellular binding-related gene sets were highly enriched in the spheroid type cells. Conclusion: 3D culture aggregation morphology represents phenotypic properties and transcriptomic profiles in non-small cell lung cancer cells. Citation Format: Naohiro Hayashi, Shimpei Tsudaka, Ken Suzawa, Tomoaki Higashihara, Yin Min Thu, Atsushi Matsuoka, Daisuke Mizuno, Ryo Yoshichika, Fumiaki Mukohara, Mao Yoshikawa, Kazuhiko Shien, Hiromasa Yamamoto, Shinichi Toyooka. 3D culture aggregation morphology depends on cell phenotype and gene expression profiles in lung cancer [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 6775.

Abstract 3941: Wild-type KRAS dosage in mutant KRAS lung cancer: Implications for tumorigenesis and therapeutic response

Abstract Lung adenocarcinomas (LUAD) are frequently driven by activating mutations in the Kirsten rat sarcoma viral oncogene homolog (KRAS). Previous studies have suggested that wild-type (wt)-RAS signaling may modulate cancer progression and drug resistance in these tumors. However, the interplay between oncogenic KRAS and wt-RAS-like GTPases in lung cancer biology and treatment remains debated. Here, we investigated the impact of increased wt-KRAS dosage in LUAD harboring mutant KRAS on lung cancer phenotypes and response to anti-KRAS therapies. Increased wt-KRAS dosage occurs in LUAD due to the loss of LZTR1, a proteostatic regulator of RAS-like GTPases. LZTR1 mutations, deletions, or downregulation co-occur with oncogenic KRAS mutations in more than 40% of LUAD patients. Using a global protein stability screen, we identified LZTR1 as the main regulator of the stability of wt-KRAS, but not of the oncogenic KRAS mutants. Proteomic analysis of LUAD cells confirmed that LZTR1 loss leads to elevated expression of wt-KRAS, but not of KRAS-G12D, indicating that LZTR1 loss affects wt-RAS rather than mutant KRAS signaling. LZTR1 loss in LUAD patients is associated with poor prognosis and hypoxic expression signatures. In a mouse model of Kras-mutated LUAD, Lztr1 haploinsufficiency promoted tumor initiation and progression. Moreover, Lztr1 loss results in hypoxic tumors with inflamed, tortuous, insufficiently perfused, and leaky vessels. Integrative proteomic and phosphoproteomic analysis revealed increased RAL/TBK1 pathway activity in LZTR1-depleted lung cancer cells and Lztr1-deleted tumors. This leads to enhanced secretion of proangiogenic and proinflammatory factors, such as VEGF and TNFα, by LZTR1-deficient cells and an increased number of neutrophils in Lztr1-deleted tumors. TNF-activated neutrophils present at vascular branching points can modulate vascular remodeling by influencing the formation and function of blood vessels. Pharmacological inhibition of RAL/TBK1 signaling with amlexanox, an anti-NF-κB/TBK1 drug, reduces TNFα secretion, decreases the number of neutrophils, and normalizes the tumor-associated vasculature. We demonstrated that increased wt-KRAS dosage, but not other small GTPases, mimicked the effects of LZTR1 loss on RAL/TBK1 signaling and VEGF secretion, suggesting that LZTR1 loss alters the heterogeneity of KRAS-mutated lung cancer by modulating wt-KRAS levels. Furthermore, MRTX1133 a selective inhibitor of KRAS-G12D, showed limited effect in the Kras-G12D, Lztr1-loss LUAD model, whereas the combination of MRTX1133 and amlexanox suppress tumor growth, likely due to the restoration of the tumor vasculature by RAL/TBK1 inhibition. Our study reveals novel insights into the role of wt-KRAS dosage in mutant KRAS lung cancer and identifies potential therapeutic strategies to target patients with dysregulated KRAS proteostasis due to LZTR1 loss. Citation Format: Tonci Ivanisevic, Greetje Vande Velde, Peihua Zhao, Wout Magits, Raj N. Sewduth, Anna A. Sablina. Wild-type KRAS dosage in mutant KRAS lung cancer: Implications for tumorigenesis and therapeutic response [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 3941.

Abstract 1702: Loss of KEAP1 promotes R-loop formation independent of NRF2

Abstract This study investigates the mechanism of R-loop formation as a consequence of KEAP1 depletion. R-loops, described as three-stranded nucleic acid structures consisting of a DNA:RNA hybrid and a non-template single-stranded DNA, are assemblies often attributed with pathological consequences like genomic instability and replication stress. However, they have significant physiological roles, inter alia, regulation of transcription initiation, splicing and termination. Loss in R-loop resolution factors (like RNaseH nucleases, senataxin) can result in “unscheduled” or “pathological” R-loops, which can compromise genome stability. R-loops are commonly associated with an active transcription bubble, with nascent RNA trailing the RNA polymerase re-annealing to the template DNA strand. Increased transcriptional stress can lead to accumulation of R-loops. In a 2016 eLife study by Stork et al., estrogen induction resulted in concomitantly increased transcription and R-loop formation in the same subset of genes. Similar to estrogen induction, activation of the NRF2/KEAP1 pathway upon oxidative stress causes NRF2 to be released from KEAP1 and enter the nucleus to turn on transcription of its target genes. Kelch-like ECH associated protein 1, encoded by the KEAP1 gene, is a canonical binding partner of NRF2. Under basal conditions, KEAP1 binds NRF2 and targets it for degradation. Mutations in KEAP1 and epigenetic modifications have been reported in lung and breast cancer phenotypes. In lieu of chemical manipulation, NRF2 can be activated by knocking down KEAP1 via RNAi. We therefore asked whether transcription activation downstream of the NRF2/KEAP1 pathway can lead to accumulation of R-loops.We have observed the consequences of depleting KEAP1 (for NRF2 activation) with RNAi on global transcription using ethynyl uridine (EU) incorporation with click-iT chemistry and flow cytometry, on R-loop levels using S9.6 antibody immunocytochemistry and on transcriptional profile changes with RNA-seq. We observe that loss of KEAP1 leads to an increased accumulation of R-loops. Surprisingly, this is not accompanied by an expected increase in transcription as measured quantitatively with EU flow cytometry. This phenomenon was found to consistently occur in various cell lines across cancer types (breast, lung). Interestingly, depleting NRF2 cannot mitigate the effects of KEAP1 loss, suggesting that KEAP1 loss-associated R-loop formation is independent of NRF2 activation. Analysis of RNA-seq data shows that TOP2 is downregulated in KEAP1 deficient cells. As TOP2 has been previously known to regulate R-loop formation, we predict that KEAP1 loss can sensitize cells to topoisomerase inhibitors.In conclusion, interaction of KEAP1 with other players in its interactome outside of NRF2 may regulate R-loop formation and therefore R-loop-induced genome instability. Citation Format: Pramiti Mukhopadhyay, Nicklas Bassani, Alexander J. Bishop. Loss of KEAP1 promotes R-loop formation independent of NRF2 [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 1702.

Discovery of first-in-class DOT1L inhibitors against the R231Q gain-of-function mutation in the catalytic domain with therapeutic potential of lung cancer

Recent research certified that DOT1L and its mutations represented by R231Q were potential targets for the treatment of lung cancer. Herein, a series of adenosine-containing derivatives were identified with DOT1LR231Q inhibition through antiproliferation assay and Western blot analysis in the H460R231Q cell. The most promising compound 37 significantly reduced DOT1LR231Q mediated H3K79 methylation and effectively inhibited the proliferation, self-renewal, migration, and invasion of lung cancer cell lines at low micromolar concentrations. The cell permeability and cellular target engagement of 37 were verified by both CETSA and DARTS assays. In the H460R231Q OE cell-derived xenograft (CDX) model, 37 displayed pronounced tumor growth inhibition after intraperitoneal administration at 20 mg/kg dose for 3 weeks (TGI = 54.38%), without obvious toxicities. A pharmacokinetic study revealed that 37 possessed tolerable properties (t1/2 = 1.93 ± 0.91 h, F = 97.2%) after intraperitoneal administration in rats. Mechanism study confirmed that 37 suppressed malignant phenotypes of lung cancer carrying R231Q gain-of-function mutation via the MAPK/ERK signaling pathway. Moreover, analysis of the binding modes between molecules and DOT1LWT/R231Q proteins put forward the “Induced-fit” allosteric model in favor to the discovery of potent DOT1L candidates.

The causal association between serum metabolites and lung cancer based on multivariate Mendelian randomization.

This study seeks to understand the causal association between serum metabolites and different lung cancer types, an area yet to be extensively studied. We Used a two-sample Mendelian randomization (TSMR) approach, utilizing 486 blood metabolites as exposures and 3 distinct lung cancer types genome-wide association studies datasets as outcomes. We employed inverse variance weighting, MR-Egger, weighted median, simple mode, and weighted mode to estimate causal effects. We performed sensitivity analyses using Cochran Q test, MR-Egger intercept test, and MR-pleiotropy residual sum and outlier (MR-PRESSO). Linkage disequilibrium score (LDSC) analysis was conducted on the selected metabolites, and common confounding single nucleotide polymorphisms were eliminated using the human genotype-phenotype association Database. Metabolic pathway analysis was performed with MetaboAnalyst 5.0 software. Subsequently, a multivariate Mendelian randomization analysis was conducted to ascertain independent risk exposures. Our findings suggest independent risk factors for specific types of lung cancer: 7-methylxanthine and isoleucine for lung adenocarcinoma, cysteine and 1-arachidonoylglycerophosphocholine are identified as independent protective and risk factors for squamous lung cancer. Undecanoate (11:0) with Linoleate (18:2n6) showed a protective effect for small cell lung cancer. Additionally, 11 metabolic pathways were associated with lung cancer. This novel perspective offers a multidimensional understanding of lung cancer phenotypes, providing valuable guidance for identifying and screening of diverse lung cancer phenotypes.

Enhancing brain metastasis prediction in non-small cell lung cancer: a deep learning-based segmentation and CT radiomics-based ensemble learning model

BackgroundBrain metastasis (BM) is most common in non-small cell lung cancer (NSCLC) patients. This study aims to enhance BM risk prediction within three years for advanced NSCLC patients by using a deep learning-based segmentation and computed tomography (CT) radiomics-based ensemble learning model.MethodsThis retrospective study included 602 stage IIIA-IVB NSCLC patients, 309 BM patients and 293 non-BM patients, from two centers. Patients were divided into a training cohort (N = 376), an internal validation cohort (N = 161) and an external validation cohort (N = 65). Lung tumors were first segmented by using a three-dimensional (3D) deep residual U-Net network. Then, a total of 1106 radiomics features were computed by using pretreatment lung CT images to decode the imaging phenotypes of primary lung cancer. To reduce the dimensionality of the radiomics features, recursive feature elimination configured with the least absolute shrinkage and selection operator (LASSO) regularization method was applied to select the optimal image features after removing the low-variance features. An ensemble learning algorithm of the extreme gradient boosting (XGBoost) classifier was used to train and build a prediction model by fusing radiomics features and clinical features. Finally, Kaplan‒Meier (KM) survival analysis was used to evaluate the prognostic value of the prediction score generated by the radiomics–clinical model.ResultsThe fused model achieved area under the receiver operating characteristic curve values of 0.91 ± 0.01, 0.89 ± 0.02 and 0.85 ± 0.05 on the training and two validation cohorts, respectively. Through KM survival analysis, the risk score generated by our model achieved a significant prognostic value for BM-free survival (BMFS) and overall survival (OS) in the two cohorts (P < 0.05).ConclusionsOur results demonstrated that (1) the fusion of radiomics and clinical features can improve the prediction performance in predicting BM risk, (2) the radiomics model generates higher performance than the clinical model, and (3) the radiomics-clinical fusion model has prognostic value in predicting the BMFS and OS of NSCLC patients.

The oncogenic role of LGR6 overexpression induced by aberrant Wnt/β-catenin signaling in lung cancer.

Molecular abnormalities in the Wnt/β-catenin pathway confer malignant phenotypes in lung cancer. Previously, we identified the association of leucine-rich repeat-containing G protein-coupled receptor 6 (LGR6) with oncogenic Wnt signaling, and its downregulation upon β-catenin knockdown in non-small cell lung cancer (NSCLC) cells carrying CTNNB1 mutations. The aim of this study was to explore the mechanisms underlying this association and the accompanying phenotypes. LGR6 expression in lung cancer cell lines and surgical specimens was analyzed using quantitative RT-PCR and immunohistochemistry. Cell growth was assessed using colony formation assay. Additionally, mRNA sequencing was performed to compare the expression profiles of cells subjected to different treatments. LGR6 was overexpressed in small cell lung cancer (SCLC) and NSCLC cell lines, including the CTNNB1-mutated NSCLC cell lines HCC15 and A427. In both cell lines, LGR6 knockdown inhibited cell growth. LGR6 expression was upregulated in spheroids compared to adherent cultures of A427 cells, suggesting that LGR6 participates in the acquisition of cancer stem cell properties. Immunohistochemical analysis of lung cancer specimens revealed that the LGR6 protein was predominantly overexpressed in SCLCs, large cell neuroendocrine carcinomas, and lung adenocarcinomas, wherein LGR6 overexpression was associated with vascular invasion, the wild-type EGFR genotype, and an unfavorable prognosis. Integrated mRNA sequencing analysis of HCC15 and A427 cells with or without LGR6 knockdown revealed LGR6-related pathways and genes associated with cancer development and stemness properties. Our findings highlight the oncogenic roles of LGR6 overexpression induced by aberrant Wnt/β-catenin signaling in lung cancer.