Lung Adenocarcinoma Cell Line Research Articles

Abstract C026: TGF-β induces an atypical EMT to evade immune mechanosurveillance in lung adenocarcinoma dormant metastasis

Abstract Epithelial-to-mesenchymal transition (EMT) plays important roles during development, injury repair, cancer invasion and metastasis. The heterogeneity of EMT programs is manifest in the diverse EMT-like phenotypes occurring during tumor progression. However, little is known about the mechanistic basis and functional role of specific forms of EMT in cancer. Here we address this question in lung adenocarcinoma (LUAD) cells that enter a dormancy period in response to TGF-β upon disseminating to distant sites. Through in vivo selection, we established dormant metastasis models from human and mouse early-stage LUAD cell lines. LUAD cells with the capacity to enter dormancy are characterized by expression of SOX2 and NKX2-1 primitive progenitor markers, whereas cells derived from overt metastases express high level of the late-stage progenitor marker Sox9. Using a TGF-β signaling reporter, we showed that in the primitive progenitors, TGF-β induces growth inhibition accompanied by a classic EMT response that subsequently transitions into an atypical mesenchymal state of round morphology as the disseminated cells establish dormancy. Prolonged treatment with TGF-β in vitro recapitulates this transition in these primitive progenitors, but not in the late-stage progenitors. Given this dramatic morphological change, we focused on actin-cytoskeleton regulators and found that TGF-β induces this transition by driving the expression of the actin-depolymerizing factor gelsolin, which changes a migratory, stress fiber-rich mesenchymal phenotype into a cortical actin-rich, spheroidal state. This transition lowers the biomechanical stiffness of metastatic progenitors, protecting them from killing by mechanosensitive cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Inhibiting this actin depolymerization process clears tissues of dormant metastatic cells. Thus, LUAD primitive progenitors undergo an atypical EMT as part of a strategy to evade immune-mediated elimination during dormancy. Our results provide a mechanistic basis and functional role of this atypical EMT response of LUAD metastatic progenitors and further illuminate the role of TGF-β as a crucial driver of immune evasive metastatic dormancy. Citation Format: Zhenghan Wang, Yassmin Elbanna, Inês Godet, Lila Peters, George Lampe, Yanyan Chen, Joao Xavier, Morgan Huse, Joan Massagué. TGF-β induces an atypical EMT to evade immune mechanosurveillance in lung adenocarcinoma dormant metastasis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C026.

Senescence cell signature associated with poor prognosis, epithelial-mesenchymal transition, solid histology, and spread through air spaces in lung adenocarcinoma.

Cellular senescence is involved in critical processes in tumor progression. Despite this potential relationship, the relationship between tumor cell senescence, prognostic significance, spread through air spaces (STAS), and tumor histology has not been investigated in lung adenocarcinoma (LUAD). We used the LUAD PanCancer Atlas dataset to assess senescence cell signature (SCS) based on the SenMayo gene set. We examined the relationship between SCS, prognostic significance, STAS, and tumor histology. This relationship was confirmed in independent LUAD datasets by validation using immunohistochemical senescence markers. In the LUAD PanCancer Atlas dataset, patients with high SCS expression had a higher prevalence of solid histology and STAS patterns than those with low SCS expression. In the independent LUAD datasets, high p21 expression and low HMGB1 expression were correlated with solid histology or STAS patterns. SCS level was also independent prognostic factor in four different LUAD datasets. The HMGB1 expression was an independent prognostic factor in the independent LUAD dataset in multivariate analysis. The expression of p21 and the presence of solid histology were linked to the epithelial-mesenchymal transition (EMT) phenotype. In LUAD cell lines, inducing senescence with a DNA-damaging agent led to an increase in EMT marker expression. Our findings suggest a strong link between senescence, EMT, and solid histology, offering valuable insight into how cancer cell senescence may promote tumor progression through particular pathways.

SOCS1 Inhibits IL-6-Induced CD155 Overexpression in Lung Adenocarcinoma

CD155, also known as the poliovirus receptor (PVR), is a crucial molecule in the development and progression of cancer, as its overexpression favors immune evasion and resistance to immunotherapy. However, little is known about the mechanisms that regulate its overexpression. Proinflammatory factors produced by various cellular components of the tumor microenvironment (TME) have been associated with CD155 expression. We analyzed the effect of interleukin (IL)-6 on CD155 expression in lung adenocarcinoma. We found a positive relationship between mRNA and protein levels. This correlation was also observed in bioinformatics analysis and in biopsies and serum from patients with lung adenocarcinoma. Interestingly, lung adenocarcinoma cell lines expressing suppressor of cytokine signaling 1 (SOCS1) did not show increased CD155 levels upon IL-6 stimulation, and SOCS1 silencing reverted this effect. IL-6 and SOCS1 are critical regulators of CD155 expression in lung adenocarcinoma. Further basic and clinical studies are needed to define the role of these molecules during tumor development and to improve their clinical impact as biomarkers and targets for predicting the efficacy of immunotherapies. This study deepens the understanding of the intricate regulation of the immune checkpoints mediated by soluble factors and allows us to devise new ways to combine conventional treatments with the most innovative anticancer options.

Silencing PPAP2C inhibits lung adenocarcinoma migration and invasion via the ERK/JNK pathway.

Lung adenocarcinoma (LUAD) is a leading cause of cancer‑related death due to its aggressive nature and metastatic potential. The present study aimed to explore the expression of phospholipid phosphatase 2 (PPAP2C) in LUAD, and its effect on cell migration and invasion, with a particular focus on its association with the ERK/JNK signaling pathway and epithelial‑mesenchymal transition (EMT). The expression of PPAP2C in LUAD was analyzed using data from The Cancer Genome Atlas database. Pearson's correlation coefficient analysis was used to assess the correlation between PPAP2C and genes such as MAPK1, MAPK3, MAPK8, CDH1, CDH2 and SNAI1. Subsequently, the PPAP2C gene was silenced in A549 and H1299 LUAD cell lines using siRNA vectors, followed by assessments of gene expression, cell migration, invasion and protein interaction using reverse transcription‑quantitative PCR, western blotting, wound healing assay, Transwell invasion assay, molecular docking analysis, co‑immunoprecipitation and immunofluorescence staining. The results showed that PPAP2C was significantly upregulated in LUAD tissues compared with that in normal tissues. In addition, high levels of PPAP2C were significantly correlated with MAPK3, MAPK8, CDH1 and SNAI1. Notably, PPAP2C silencing significantly inhibited cell migration and invasion. Additionally, it reduced the phosphorylation levels of ERK and JNK proteins. PPAP2C showed specific binding sites with ERK1, and co‑precipitated with ERK1 in both A549 and H1299 cells. Furthermore, PPAP2C silencing decreased the expression levels of N‑cadherin and Snail, while increasing E‑cadherin expression, thereby inhibiting EMT. In conclusion, PPAP2C may be highly expressed in LUAD tissues, and could promote cell migration and invasion by activating the ERK/JNK signaling pathway and inducing EMT. These findings provide a novel potential target for the diagnosis and treatment of LUAD.

Extracellular Vesicles from Lung Adenocarcinoma Cells Induce Activation of Different Cancer-Associated Fibroblast Subtypes

Background: Lung cancer, including the major subtype lung adenocarcinoma (LUAD), is the leading cause of cancer deaths worldwide, largely due to metastasis. Improving survival rates requires new treatment strategies and a deeper understanding of the mechanisms that drive tumor progression within the tumor microenvironment (TME). This study investigated the impact of extracellular vesicles (EVs) derived from LUAD cells on lung fibroblasts. Methods: EVs were isolated from LUAD cell lines via ultracentrifugation and characterized using nanoparticle tracking analysis and Western blotting. Lung fibroblasts were treated with PBS, TGFβ, or EVs, and their activation was assessed through protein (Western blotting) and RNA analyses (RNA seq and RT-qPCR). Results: The results confirmed the TGFβ induced activation and showed that LUAD EVs could also activate fibroblasts, increasing cancer-associated fibroblast (CAF) markers. While EV-induced CAF activation displayed unique features, like an increase in proliferation-related genes, the EV and TGFβ treatments also shared some differentially expressed genes. The EV groups induced a higher expression of ECM remodeling and EMT-associated genes, but some of those genes were also upregulated in the TGFβ group. Mesenchymal genes POSTN and SPOCK1 were significantly upregulated in TGFβ- and EV-treated fibroblasts. Their secretion as proteins from the TGFβ- and EV-induced CAFs was not significant, confirmed through ELISA. Conclusions: These findings suggest that LUAD EVs play a role in CAF activation through both shared and distinct pathways compared to canonical TGFβ activation, potentially identifying novel gene expressions involved in CAF activation. Additionally, optimal protein secretion conditions of confirmed CAF-upregulated genes need to be established to determine their contribution to the TME.

MLLT3 knockdown suppresses proliferation and cell mobility in human lung adenocarcinoma.

Lung cancer is emerging as one of the most frequently encountered malignancies around the world that carries high morbidity and mortality. Lung adenocarcinoma (LUAD) has become the most common subtype of lung cancer. MLLT3 or named AF9 was first characterized in acute myeloid leukemia and can downregulate the expression of several critical genes. The aim of this study was to explore the function of MLLT3 in the progression of LUAD and related molecular mechanisms. Immunohistochemistry was employed to assess MLLT3 expression in LUAD tissues, while quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were utilized to detect MLLT3 expression levels in lung adenocarcinoma cell lines. These results revealed a significant overexpression of MLLT3 in LUAD cell lines and tissues. We further uncovered an association between MLLT3 expression profiles in LUAD tissues and metastasis, as well as TNM stage. Survival analysis showed that elevated MLLT3 correlated with a poorer survival rate. We also found that MLLT3 knockdown repressed LUAD cells invasion, migration, and proliferation in vitro, while inducing cell cycle arrest and apoptosis of LUAD cells. Moreover, knocking down MLLT3 inhibited tumor growth in vivo. Specific markers of apoptosis, cell cycle, epithelial-mesenchymal transition (EMT), and MLLT3-induced signaling were examined by Western blot. We demonstrated that MLLT3 knockdown inhibited the activity of the EGFR-MAPK/ERK signaling pathway, and MLLT3 might be a novel diagnostic biomarker and therapeutic target in lung adenocarcinomas.

LNX1-AS2 as a Key Prognostic and Immunotherapy Response Biomarker for Lung Adenocarcinoma.

The role of LNX1 antisense RNA 2 (LNX1-AS2) in lung adenocarcinoma (LUAD) remains unclear. This study aimed to investigate the association between LNX1-AS2 and LUAD by employing bioinformatics analysis and experimental validation. Statistical analysis and database interrogation were utilized to assess correlations among LNX1-AS2 expression, clinical characteristics of LUAD patients, prognostic factors, regulatory networks, and immune infiltration. LNX1-AS2 expression in LUAD cell lines was quantified using quantitative real-time polymerase chain reaction (qRT-PCR). The study found significantly elevated levels of LNX1-AS2 expression in patients with LUAD. Furthermore, elevated LNX1-AS2 expression in LUAD patients did not significantly correlate with gender (p = 0.041) or race (p = 0.049). Importantly, high LNX1-AS2 expression levels were associated with poorer overall survival (OS, p = 0.042) and disease-specific survival (DSS, p = 0.040) in LUAD patients. Additionally, high LNX1-AS2 expression (p = 0.015) was independently correlated with OS in LUAD patients. The phenotype characterized by high LNX1-AS2 expression was also found to be enriched for asthma, allograft rejection, drug metabolism cytochrome P450, metabolism of xenobiotics by cytochrome P450, olfactory transduction, renin-angiotensin system, retinol metabolism, pentose and glucuronate interconversions, and porphyrin and chlorophyll metabolism. A significant correlation was identified between the expression levels of LNX1-AS2 and immune infiltration in the context of LUAD. Elevated expression of LNX1-AS2 was notably detected in LUAD cell lines as opposed to Beas-2B. A noteworthy relationship was established among increased LNX1-AS2 expression in LUAD patients, unfavorable prognosis, and heightened immune infiltration. These findings suggest that the LNX1-AS2 gene could serve as a valuable prognostic indicator for LUAD and a potential predictor of response to immunotherapy.

Characterizing dynamic tumor-immune interactions in lung adenocarcinoma through orthotopic allograft modeling.

The major clinical challenge in lung cancer immunotherapy is drug resistance. Therefore, establishing efficient orthotopic lung cancer mouse models to explore the mechanisms of drug immunotherapy resistance is highly important. In this study, we generated multiple fluorescently labeled lung adenocarcinoma cell lines from agenetically engineered KPZ mice model. Orthotopic transplantation of the primary 1F3 cell line induced a strong immune response, causing many small tumors to disappear, but some tumors evaded the immune attack and eventually formed large tumors. Tumor microenvironment analysis demonstrated that M2 macrophages play key roles in the immune response. Further mechanistic studies revealed that the chemokine CCL7 promoted the infiltration of M2 macrophages to facilitate immune escape, thereby promoting tumor growth in the orthotopic mouse model. Moreover, CCL7 levels were elevated in human lung cancer biopsies and positively correlated with M2 macrophage infiltration, and high CCL7 levels predicted advanced pathological stage and poor survival in lung cancer patients. Overall, we established a visualized and orthotopic mouse model with fluorescently labeled cells to better dissect the tumor microenvironment of lung cancer and define the critical role of CCL7 in promoting M2 macrophage polarization and tumorigenesis, providing new preclinical tools and potential targets for lung cancer immunotherapy.

Epigenetic Regulation of CXC Chemokine Expression by Environmental Electrophiles Through DNA Methyltransferase Inhibition.

Ubiquitously distributed environmental electrophiles covalently modify DNA and proteins, potentially leading to adverse health effects. However, the impacts of specific electrophiles on target proteins and their physiological roles remain largely unknown. In the present study, we focused on DNA methylation, which regulates gene expression and physiological responses. A total of 45 environmental electrophiles were screened for inhibitory effects on the activity of DNA methyltransferase 3B (DNMT3B), a key enzyme in DNA methylation, and four compounds were identified. We focused on 1,2-naphthoquinone (1,2-NQ), an air pollutant whose toxicity has been reported previously. Interestingly, we found that 1,2-NQ modified multiple lysine and histidine residues in DNMT3B, one of which was near the active site in DNMT3B. It was found that 1,2-NQ altered gene expression and evoked inflammatory responses in lung adenocarcinoma cell lines. Furthermore, we found that 1,2-NQ upregulated CXCL8 expression through DNA demethylation of the distal enhancer and promoted cancer cell growth. Our study reveals novel mechanisms of epigenetic regulation by environmental electrophiles through the inhibition of DNMT3B activity and suggests their physiological impact.

S100A16 stabilizes the ITGA3‑mediated ECM‑receptor interaction pathway to drive the malignant properties of lung adenocarcinoma cells via binding MOV10.

Lung adenocarcinoma (LUAD) is highly associated with lung cancer‑associated mortality. Notably, S100 calcium‑binding protein A16 (S100A16) has been increasingly considered to have prognostic value in LUAD; however, the underlying mechanism remains unknown. In the present study, S100A16 expression levels in LUAD tissues and cells were respectively analyzed by the UALCAN database and western blotting. Cell Counting Kit‑8 and 5‑ethynyl‑2'‑deoxyuridine assays were used to examine cell proliferation, whereas wound healing, Transwell and tube formation assays were used to assess cell migration, invasion and angiogenesis, respectively. Western blotting was also used to examine the expression levels of proteins associated with metastasis, angiogenesis, focal adhesion and the extracellular matrix (ECM)‑receptor interaction pathways. The relationship between S100A16 and Mov10 RNA helicase (MOV10) was predicted by bioinformatics tools, and was verified using a co‑immunoprecipitation assay. Furthermore, the interaction between MOV10 and integrin α3 (ITGA3) was verified by RNA immunoprecipitation assay, and the actinomycin D assay was used to detect ITGA3 mRNA stability. The results demonstrated that S100A16 expression was increased in LUAD tissues and cell lines, and was associated with unfavorable outcomes. Knocking down S100A16 expression hindered the proliferation, migration, invasion and angiogenesis of LUAD cells. Furthermore, S100A16 was shown to bind to MOV10 and positively modulate MOV10 expression in LUAD cells, while MOV10 overexpression partially reversed the suppressive role of S100A16 knockdown on the aggressive phenotypes of LUAD cells. Furthermore, it was demonstrated that S100A16 regulated the stability of ITGA3 mRNA via MOV10 to mediate ECM‑receptor interactions. In conclusion, S100A16 may bind to MOV10 to stabilize ITGA3 mRNA and regulate ECM‑receptor interactions, hence contributing to the malignant progression of LUAD.

Treatment of a mutant KRAS lung cancer cell line with polyisoprenylated cysteinyl amide inhibitors activates the MAPK pathway, inhibits cell migration and induces apoptosis.

KRAS mutations are the most common oncogenic mutations in lung adenocarcinoma in Black Americans. Polyisoprenylated Cysteinyl amide Inhibitors (PCAIs) constitute a group of potential cancer therapy agents that we designed to specifically disrupt and suppress hyperactive G-protein signaling, such as that caused by mutated RAS proteins. Here we determine the effects of PCAIs on the viability, G-protein levels, downstream mediators, and apoptosis-related proteins on the KRAS-mutated, Black American-derived lung adenocarcinoma cell line, NCI-H23. Of the 17 PCAIs tested, compounds NSL-YHJ-2-27 and NSL-YHJ-2-46 showed the most potency with EC50 values of 2.7 and 3.3 μM, respectively. Western blotting was used to determine the effect of the PCAIs on the phosphorylation levels of MAPK pathway enzymes. After 48 h exposure to 5 μM of the PCAIs, NSL-YHJ-2-46, the MAPK proteins BRAF, MEK1/2, ERK1/2, and p90RSK were activated through phosphorylation by 90, 190, 150 and 120%, respectively. However, CRAF/RAF1 phosphorylation decreased by 40%, suggesting significant changes in the KRAS/MAPK signaling patterns. Furthermore, 5 μM of NSL-YHJ-2-27 depleted the singly polyisoprenylated monomeric G-proteins RAC 1/2/3 and CDC42 by 77 and 76%, respectively. The depletion of these key cytoskeletal proteins may account for the observed inhibition of cell migration and invasion, and spheroid invasion observed on exposure to NSL-YHJ-2-27 and NSL-YHJ-2-46. Treatment with 5 μM of NSL-YHJ-2-27 suppressed full-length inactive caspase 3 and 7 levels by 72 and 91%, respectively. An analysis of cells treated with the fluorescently labeled active caspase 3/7 irreversible inhibitor, CaspaTagTM Caspase-3/7 in situ reagent revealed a 124% increase in active caspase at 3 μM over controls. These findings clearly show the direct effects of the PCAIs on the RAS signaling pathway. Given the profound increases observed in RPS6KA1/p90RSK phosphorylation, future work will involve a determination whether the proapoptotic isoforms of RPS6KA1/p90RSK are phosphorylated due to the PCAIs treatments. These results support the potential use of the PCAIs as targeted therapies against cancers with KRAS mutations.

High expression of LINC00467 promotes proliferation and metastasis of lung adenocarcinoma cells by suppressing autophagy via inhibiting the AMPK/mTOR pathway

To investigate the regulatory effects of LINC00467 on proliferation and metastasis of lung adenocarcinoma cells and the involvement of autophagy in its regulatory mechanism. LINC00467 expression levels in lung adenocarcinoma tissues and their correlation with the patients' survival outcomes were analyzed using data from TCGA database. LINC00467 expression was also examined using qRT-PCR in human bronchial epithelial cells 16HBE and lung adenocarcinoma cell lines A549 and H1299. In A549 and H1299 cells transfected with a short hairpin RNA targeting LINC00467 (shLINC00467), the effects of 3-methyladenine (3-MA, an autophagy inhibitor) and BML-275 (an AMPK inhibitor) treatment on cell proliferation, migration, and expressions of LC3 and the AMPK/mTOR pathway proteins were tested using colony formation assay, wound-healing and Transwell assays, immunofluorescence staining and Western blotting. GSEA enrichment analysis was conducted to analyze the correlation between LINC00467 and the autophagy pathway. The expression level of LINC00467 was significantly higher in lung adenocarcinoma tissues than in the adjacent tissues (P < 0.001) and increased progressively with the clinical stage (P < 0.05), and its high expression was associated with a poor overall survival (P= 0.049) and a high first progression rate (P=0.026) of the patients. LINC00467 expression was also significantly higher in A549 and H1299 cells than in 16HBE cells. In A549 and H1299 cells, LINC00467 knockdown significantly decreased colony-forming, migration and invasion abilities of the cells, lowered p-mTOR/mTOR and p62 expressions, and increased p-AMPK/AMPK expressions and LC3Ⅱ/Ⅰ ratio, and these effects were strongly attenuated by application of either 3-MA or BML-275. GSEA analysis suggested an inhibitory effect on LINC00467 on the autophagy pathway (|NES| > 1, P < 0.05, FDR < 0.25). High expressions of LINC00467 promote proliferation and metastasis of lung adenocarcinoma cells possibly by inhibiting cell autophagy mediated by the AMPK/mTOR signaling pathway.

MEF2C is a Potential Prognostic Biomarker and is Correlated with Immune Infiltrates in Lung Adenocarcinoma.

The role of Myocyte Enhancer Factor 2 C (MEF2C) in lung adenocarcinoma (LUAD) is unclear. To address this gap in knowledge, we employed bioinformatics analysis and experimental validation in this study. This study investigated MEF2C expression across a spectrum of cancers, with a specific focus on lung adenocarcinoma (LUAD), utilizing Cancer Genome Atlas (TCGA) data to assess its potential as a diagnostic marker. The study also investigated correlations between MEF2C expression and clinical traits and prognostic indicators of LUAD. Additionally, this study also delved into the regulatory mechanisms of MEF2C, examining its connections to immune system interactions, immune checkpoint genes, tumor mutational burden (TMB), and the sensitivity of LUAD to various drugs. Through single-cell sequencing of LUAD cells and genetic variation of MEF2C in LUAD, we explored the expression of MEF2C in cell lines and verified it by quantitative real-time PCR (qRT-PCR). MEF2C exhibited aberrant expression in both pan-cancer and LUAD. In individuals with LUAD, diminished levels of MEF2C expression were notably linked to the effectiveness of primary therapy outcome (p = 0.025), gender (p < 0.001), and the subdivision of anatomic neoplasms 2 (p = 0.011). A decline in MEF2C levels was also found to be significantly related to reduced overall survival (OS) in LUAD patients (p = 0.026). The presence of MEF2C was recognized as a standalone factor predictive of prognosis in LUAD (p = 0.029). MEF2C was found to be involved in multiple biological pathways, such as those involving cell adhesion molecules. Additionally, its expression was correlated with the extent of immune cell presence, the activity of immune checkpoint genes, and TMB in LUAD. Notably, an inverse relationship was observed between MEF2C expression and the sensitivity to several agents, including Topotecan, Irinotecan, Panobinostat, Nilotinib, and Tp38-279, within the context of LUAD. Furthermore, MEF2C was found to be significantly negatively regulated in LUAD cell lines. The results imply that MEF2C could be a valuable indicator for predicting outcomes and a possible target for immunotherapy for LUAD patients.

MicroRNA-130a-3p regulates osimertinib resistance by targeting runt-related transcription factor 3 in lung adenocarcinoma

Overcoming resistance to epidermal growth factor receptor tyrosine kinase inhibitors, including osimertinib, is urgent to improve lung cancer treatment outcomes. Extracellular vesicle (EV)-derived microRNAs (EV-miRNAs) play important roles in drug resistance and serve as promising biomarkers. In this study, we aimed to identify EV-miRNAs associated with osimertinib resistance and investigate their clinical relevance. The release of excess EVs was confirmed in the osimertinib-resistant lung adenocarcinoma cell line PC9OR. The exposure of PC9OR-derived EVs and EV-miRNAs to PC9 cells increased cell viability after osimertinib treatment. Microarray analysis revealed that miR-130a-3p was upregulated in EVs derived from PC9OR cells and another osimertinib-resistant cell line (H1975OR). Transfection with miR-130a-3p attenuated osimertinib-induced cytotoxicity and apoptosis in both PC9 and H1975 cells, whereas osimertinib resistance in PC9OR cells was reversed after miR-130a-3p inhibition. Bioinformatics analysis revealed that runt-related transcription factor 3 is a target gene of miR-130a-3p, and it induced osimertinib resistance in PC9 cells. Patients with lower baseline serum miR-130a-3p concentrations had longer progression-free survival. miR-130a-3p is a potential therapeutic target and a predictive biomarker of osimertinib resistance in adenocarcinomas.

RBM15 drives the progression of lung adenocarcinoma by regulating N6-methyladenosine-mediated LDHA mRNA stability

Abnormal N6-methyladenosine (m6A) methylation in RNA plays a pivotal role in the pathogenesis of many types of tumors by influencing mRNA metabolism, alternative splicing, translocation, stability and translation. However, the specific regulators and underlying mechanisms of m6A modification in the progression of lung adenocarcinoma are not well understood. In this study, we analyzed the RNA-seq transcriptome data downloaded from The Cancer Genome Atlas (TCGA) database, and identified “m6A writer” RNA binding motif protein 15 (RBM15) expression was significantly elevated in lung adenocarcinoma (LUAD) biopsies, and the higher RBM15 levels were correlated with the poorer overall survival (OS) of LUAD patients. Further study confirmed RBM15 was prominently expressed in LUAD tissues and cell lines. Moreover, silencing RBM15 in PC9 and H1299 cells reduced cell proliferation both in vitro and in vivo, while overexpression of RBM15 in A549 cells promoted cell growth. Mechanistically, lactate dehydrogenase A (LDHA) acted as a downstream target of RBM15. RBM15-mediated m6A modification of LDHA mRNA enhanced its stability to exert an oncogenic role in LUAD. Taken together, our findings suggest that the RBM15/LDHA axis might be a novel and promising therapeutic target for LUAD.

Exploring the effects of pemetrexed on drug resistance mechanisms in human lung adenocarcinoma and its association with PGRMC1

According to the 2022 cancer statistics of the World Health Organization, lung cancer ranks among the top ten causes of death, with lung adenocarcinoma being the most prevalent type. Despite significant advancements in lung cancer therapeutics, many clinical limitations remain, primarily due to the development of drug resistance. The present study investigated the effects of pemetrexed on the drug resistance mechanisms in human lung adenocarcinoma and its association with progesterone receptor membrane component 1 (PGRMC1) expression. Given that KRAS-mutant lung adenocarcinoma cell lines (e.g., A549) exhibit a high folate synthesis activity, pemetrexed, which is structurally similar to folate, was selected as the therapeutic drug. The present study used a lung adenocarcinoma cell line (A549) and established a drug-resistant lung adenocarcinoma cell line (A549/PEM). The findings demonstrated that PGRMC1 expression was elevated in the A549/PEM cells. It has been hypothesized that PGRMC1 regulates iron absorption through heme binding, resulting in a preference for iron-related cell death pathways (ferroptosis). Our findings indicate that drug-resistant lung adenocarcinoma cells with high PGRMC1 levels exhibit elevated antioxidant activity on the cell membrane and increased reliance on iron-dependent cell death pathways. This suggests a correlation between PGRMC1 and pemetrexed-induced iron-dependent cell death. Our study contributes to the development of more effective therapeutic strategies to improve the prognosis of patients with lung adenocarcinoma, particularly those facing drug resistance challenges.

Antimicrobial, Anti-biofilm, Anti-swarming, Anti-quorum Sensing Activities, and Cytotoxicity of Propolis Samples from Northeast of Türkiye

Aim of study: Studies on propolis have increased as it has been revealed that it contains biologically active molecules. In the current study, it was aimed to analyze biological activity, and cytotoxicity of ethanolic extract of three different propolis samples from Türkiye. Material and methods: The antibacterial activity of the extracts against 14 microorganisms was assessed using the agar well diffusion method and the microdilution method. Chromobacter violeceum was used in quorum-sensing assay, and Pseudomonas aeruginosa PAO1 strain was used in swarming and biofilm assays. Using the MTT test, the cytotoxic effect of the extracts was examined on the lung adenocarcinoma cell line (A549), pancreatic tumoral cell line (AR42J), breast cancer cell line (MDA-MB-231), and normal epithelial cell line (Vero). Main results: All propolis extracts were effective against 8/14 microorganisms included in the study. While all propolis extracts have shown anti-quorum sensing activity, there was not any anti-swarming and anti-biofilm activity in each sample. It was demonstrated that every propolis sample had a dose-dependent cytotoxic effect on the examined cell lines. Research highlights: Due to the biological activity shown by the propolis samples included in the study, it is considered that it has the potential to influence the creation of novel medications in the future.

Global profiling of transcriptome, proteome and 2-hydroxyisobutyrylome in radioresistant lung adenocarcinoma cell

Radioresistance contributes to metastasis and recurrence in non-small cell lung cancer (NSCLC) patients. However, the underlying mechanism remains unclear. To provide novel clues, a complete multi-omics map of a radioresistant cancer cell line has been profiled. In this article, a lung adenocarcinoma cell line, radioresistant A549 (RA549), was generated by exposure to a series of irradiation. Subsequently, we adopted transcriptome, quantitative proteome and lysine 2-hydroxyisobutyrylome to construct a differential profile on the transcriptional to post-tanslational levels on A549 and RA549 cell lines, respectively. Our analysis revealed 920 significantly differentially expressed genes and 699 proteins. Furthermore, 2-hydroxyisobutyrylome identified 30,089 Khib modified sites on 4635 proteins, indicating that Khib modifications play vital role in regulating NSCLC radioresistance. Multi-omics combined analysis identified 19 significantly differentially expressed genes/proteins in total. Meanwhile, we found that EGFR, a well-known lung cancer-related receptor, was upregulated at both the protein and Khib modification levels in RA549. Further gain/loss of function experiments showed that Khib modified EGFR level positively correlates with NSCLC cell radioresistance. Taken together, our findings report that Khib-modified proteins enhanced resistance to radiation and represent promising therapeutic targets.

Unveiling the Enigmatic Role of SLC35F3 in Lung Adenocarcinoma.

The role of solute carrier family 35 member F3 (SLC35F3) in lung adenocarcinoma (LUAD) remains unclear. To address this gap, we conducted a study employing bioinformatics analysis and experimental validation. This study aimed to examine the expression patterns of SLC35F3 in various cancer types, particularly focusing on LUAD, by analyzing data from the Cancer Genome Atlas (TCGA) database to evaluate its clinical relevance. The research also explored potential regulatory mechanisms of SLC35F3, including its interactions with immune infiltration, tumor mutational burden (TMB), and drug sensitivity in LUAD. The investigation included analyzing SLC35F3 expression in single-cell sequencing of LUAD cells, examining genetic variations of SLC35F3 in LUAD, and assessing SLC35F3 expression in cell lines using quantitative real-time PCR (qRT-PCR). The aberrant expression of SLC35F3 was observed in both pan-cancer and LUAD. In LUAD patients, a statistically significant increase in SLC35F3 expression was correlated with gender (p < 0.001) and was associated with poorer overall survival (OS) (p = 0.020). The expression of SLC35F3 was identified as an independent prognostic determinant in patients with LUAD (p = 0.032). SLC35F3 exhibited associations with various pathways, including cell cycle and more. SLC35F3 expression demonstrated correlations with immune infiltration, TMB, and some drugs in LUAD. Results indicated significant upregulation of SLC35F3 in both LUAD tissues and cell lines. SLC35F3 may serve as a prognostic biomarker and immunotherapeutic target for patients with LUAD. Not applicable.

A novel molecular target, superoxide dismutase 1, in ALK inhibitor-resistant lung cancer cells, detected through proteomic analysis

BackgroundsTo the best of our knowledge, there are no reports of proteomic analysis for the identification of unknown proteins involved in resistance to anaplastic lymphoma kinase (ALK) inhibitors. In this study, we investigated the proteins involved in resistance to alectinib, a representative ALK inhibitor, through proteomic analysis and the possibility of overcoming resistance. MethodsAn ALK-positive lung adenocarcinoma cell line (ABC-11) and the corresponding alectinib-resistant cell line (ABC-11/CHR2) were used. Two-dimensional difference gel electrophoresis (2D DIGE) was performed; the stained gel was scanned and the spots were analyzed using DeCyder TM2D 7.0. Mass spectrometry (MS) with the UltrafleXtreme matrix-assisted laser desorption ionization-tandem time-of-flight (MALDI-TOF/TOF) MS system was performed. For the MS/MS analysis, the samples were spotted on an AnchorChipTM 600 TF plate. The peptide masses obtained in the reflector positive mode were acquired at m/z of 400−6,000. MS/MS data were searched against the NCBI protein databases. Growth inhibition was measured using an MTT assay. The isobologram and combination index were calculated based on the median-effect analysis. Western blotting was performed using antibodies, including superoxide dismutase (SOD) 1, MET, ERK, PARP, AKT, and BRCA1. ResultsThe 2D DIGE for ABC-11 and ABC-11/CHR2 showed different expression levels in about 2,000 spots. SOD was identified from spots highly expressed in resistant strains. Western blotting also confirmed SOD1 overexpression in ABC-11/CHR2. siSOD1 enhanced the growth inhibitory effects of alectinib, increased cleaved PARP levels, and decreased pERK, pAKT, and BRCA1 levels with a combination of alectinib. In addition, the combination of LCS-1, an SOD1 inhibitor, and alectinib synergistically suppressed the growth in ABC-11/CHR2, but not in ABC-11. ConclusionsSOD1 overexpression is thought to be a mechanism for alectinib resistance, suggesting the possibility of overcoming resistance using SOD1 inhibitors.