Biological Role Research Articles

Lung cancer cell-derived exosomes: progress on pivotal role and its application in diagnostic and therapeutic potential.

Lung cancer is frequently detected in an advanced stage and has an unfavourable prognosis. Conventional therapies are ineffective for the treatment of metastatic lung cancer. While certain molecular targets have been identified as having a positive response, the absence of appropriate drug carriers prevents their effective utilization. Lung cancer cell-derived exosomes (LCCDEs) have gained attention for their involvement in the development of cancer, as well as their potential for use in diagnosing, treating, and predicting the outcome of lung cancer. This is due to their biological roles and their inherent ability to transport biomolecules from the donor cells. Lung cancer-associated cell-derived extracellular vesicles (LCCDEVs) have the ability to enhance cell proliferation and metastasis, influence angiogenesis, regulate immune responses against tumours during the development of lung cancer, control drug resistance in lung cancer treatment, and are increasingly recognised as a crucial element in liquid biopsy evaluations for the detection of lung cancer. Therapeutic exosomes, which possess inherent intercellular communication capabilities, are increasingly recognised as effective vehicles for targeted drug delivery in precision medicine for tumours. This is due to their exceptional biocompatibility, minimal immunogenicity, low toxicity, prolonged circulation in the bloodstream, biodegradability, and ability to traverse different biological barriers. Currently, multiple studies are being conducted to create new means of diagnosing and predicting outcomes using LCCDEs, as well as to develop techniques for utilizing exosomes as effective carriers for medication delivery. This paper provides an overview of the current state of lung cancer and the wide range of applications of LCCDEs. The encouraging findings and technologies suggest that the utilization of LCCDEs holds promise for the clinical treatment of lung cancer patients.

Development of a Versatile High-through-put Oligonucleotide LC-MS Method to Accelerate Drug Discovery.

Liquid chromatography-mass spectrometry (LC-MS) is an effective tool for high-throughput quantification of oligonucleotides that is crucial for understanding their biological roles and developing diagnostic tests. This paper presents a high-throughput LC-MS/MS method that may be versatilely applied for a wide range of oligonucleotides, making it a valuable tool for rapid screening and discovery. The method is demonstrated using an in-house synthesized MALAT-1 Antisense oligonucleotide (ASO) as a test case. Biological samples were purified using a reversed liquid-liquid extraction process automated by a liquid handling workstation and analyzed with ion-pairing LC-MS/MS. The assay was evaluated for sensitivity (LLOQ = 2nM), specificity, precision, accuracy, recovery, matrix effect, and stability in rat cerebrospinal fluid (CSF) and plasma. Besides some existing considerations such as column selection, ion-pairing reagent, and sample purification, our work focused on the following four subtopics: 1) selecting the appropriate Multiple Reaction Monitoring (MRM) transition to maximize sensitivity for trace-level ASO in biological samples; 2) utilizing a generic risk-free internal standard (tenofovir) to avoid crosstalk interference from the oligo internal standard commonly utilized in the LC-MS assay; 3) automating the sample preparation process to increase precision and throughput; and 4) comparing liquid-liquid extraction (LLE) and solid-phase extraction (SPE) as sample purification methods in oligo method development. The study quantified the concentration of MALAT-1 ASO in rat CSF and plasma after intrathecal injection and used the difference between the two matrices to evaluate the injection technique. The results provide a solid foundation for further internal oligonucleotide discovery and development.

Lactylation in cancer: Current understanding and challenges

Lactylation, a recently identified post-translational modification, has initially been linked to gene transcription regulation through epigenetic mechanisms. However, its role in tumorigenesis-whether as a major driver or a minor regulator-remains uncertain. Here, we summarize the current understanding of lactylation and discuss the inherent challenges in definitively attributing specific biological roles to this modification. We emphasize the necessity for precise methodologies to manipulate lactylation levels within pathophysiologically relevant conditions. Further investigation is required to determine whether lactylation plays a critical role in tumor biology or merely reflects secondary metabolic alterations.

Plasma-derived extracellular vesicles miR-335–5p as potential diagnostic biomarkers for fusion-positive rhabdomyosarcoma

BackgroundRhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma, with embryonal (ERMS) and alveolar (ARMS) representing the two most common histological subtypes. ARMS shows poor prognosis, being often metastatic at diagnosis. Thus, the discovery of novel biomarkers predictive of tumor aggressiveness represents one of the most important challenges to overcome and may help the development of tailored therapies. In the last years, miRNAs carried in extracellular vesicles (EVs), small vesicles of endocytic origin, have emerged as ideal candidate biomarkers due to their stability in plasma and their tissue specificity.MethodsEVs miRNAs were isolated from plasma of 21 patients affected by RMS and 13 healthy childrens (HC). We performed a miRNA profile using the Serum/Plasma Focus microRNA PCR panels (Qiagen), and RT-qPCR for validation analysis. Statistically significant (p < 0.05) miRNAs were obtained by ANOVA test.ResultsWe identified nine EVs miRNAs (miR-483-5p, miR-132-3p, miR-766-3p, miR-454-3p miR-197-3p, miR-335-3p, miR-17-5p, miR-486-5p and miR-484) highly upregulated in RMS patients compared to HCs. Interestingly, 4 miRNAs (miR-335-5p, miR-17-5p, miR-486-5p and miR-484) were significantly upregulated in ARMS samples compared to ERMS. In the validation analysis performed in a larger group of patients only three miRNAs (miR-483-5p, miR-335-5p and miR-484) were differentially significantly expressed in RMS patients compared to HC. Among these, mir-335-5p was significant also when compared ARMS to ERMS patients. MiR-335-5p was upregulated in RMS tumor tissues respect to normal tissues (p = 0.00202) and upregulated significantly between ARMS and ERMS (p = 0.04). Furthermore, the miRNA expression correlated with the Intergroup Rhabdomyosarcoma Study (IRS) grouping system, (p = 0.0234), and survival (OS, p = 0.044; PFS, p = 0.025). By performing in situ hybridization, we observed that miR-335-5p signal was exclusively in the cytoplasm of cancer cells.ConclusionWe identified miR-335-5p as significantly upregulated in plasma derived EVs and tumor tissue of patients affected by ARMS. Its expression correlates to stage and survival in patients. Future studies are needed to validate miR-335-5p as prognostic biomarker and to deeply elucidate its biological role.

Genome-Wide Identification and Expression Analysis of the MADS-Box Gene Family in Cassava (Manihot esculenta)

The MADS-box gene family constitutes a vital group of transcription factors that play significant roles in regulating plant growth, development, and signal transduction processes. However, research on the MADS-box genes in cassava (Manihot esculenta) has been relatively limited. To gain deeper insights into the functions of the MADS-box genes in cassava development, in this study, we undertook a comprehensive genome-wide identification of the MADS-box gene family in cassava. We identified a total of 86 MADS-box genes with complete domains in the cassava genome, designated as MeMADS01 to MeMADS86. Through bioinformatic analyses, we investigated the basic physicochemical properties, conserved motifs, chromosomal locations, and phylogenetic relationships of the cassava MADS-box genes. The MADS-box gene family of cassava exhibited conservation, as well as species-specific characteristics, with intron loss being a predominant mode of evolution for the MADS-box genes. Expression pattern variations in the MeMADS genes across different tissues offer insights into their potential functions. Time-ordered gene co-expression network (TO-GCN), transcriptome data, and RT-qPCR analysis suggested the responsiveness of the MADS-box genes to drought stress. Meanwhile, MeMADS12 might be involved in regulating flowering under drought conditions via an ABA (abscisic acid)-dependent pathway. These findings provide valuable resources for a deeper understanding of the biological roles of the MADS-box genes in cassava.

PET Imaging of the Serotonin 1A Receptor in Major Depressive Disorder: Hierarchical Multivariate Analysis of [11C]WAY100635 Overcomes Outcome Measure Discrepancies

Abstract The serotonin 1A receptor has been linked to both the pathophysiology of major depressive disorder (MDD) and the antidepressant action of serotonin reuptake inhibitors. Most PET studies of the serotonin 1A receptor in MDD used the receptor antagonist radioligand, [carbonyl-11C]WAY100635; however the interpretation of the combined results has been contentious owing to reports of higher or lower binding in MDD with different outcome measures. The reasons for these divergent results originate from several sources, including properties of the radiotracer itself, which complicate its quantification and interpretation; as well as from previously reported differences between MDD and healthy volunteers in both reference tissue binding and plasma free fraction, which are typically assumed not to differ. Recently, we have developed two novel hierarchical multivariate methods which we validated for the quantification and analysis of [11C]WAY100635, which show better accuracy and inferential efficiency compared to standard analysis approaches. Importantly, these new methods should theoretically be more resilient to many of the factors thought to have caused the discrepancies observed in previous studies. We sought to apply these methods in the largest [11C]WAY100635 sample to date, consisting of 160 individuals, including 103 MDD patients, of whom 50 were not-recently-medicated and 53 were antidepressant-exposed, as well as 57 healthy volunteers. While the outcome measure discrepancies were substantial using conventional univariate analysis, our multivariate analysis techniques instead yielded highly consistent results across PET outcome measures and across pharmacokinetic models, with all approaches showing higher serotonin 1A autoreceptor binding potential in the raphe nuclei of not-recently-medicated MDD patients relative to both healthy volunteers and antidepressant-exposed MDD patients. Moreover, with the additional precision of estimates afforded by this approach, we can show that while binding is also higher in projection areas in this group, these group differences are approximately half of those in the raphe nuclei, which are statistically distinguishable from one another. These results are consistent with the biological role of the serotonin 1A autoreceptor in the raphe nuclei in regulating serotonin neuron firing and release, and with preclinical and clinical evidence of deficient serotonin activity in MDD due to over expression of autoreceptors resulting from genetic and/or epigenetic effects. These results are also consistent with downregulation of autoreceptors as a mechanism of action of selective serotonin reuptake inhibitors. In summary, the results using multivariate analysis approaches therefore demonstrate both face and convergent validity, and may serve to provide a resolution and consensus interpretation for the disparate results of previous studies examining the serotonin 1A receptor in MDD.

Clinical Value Evaluation of SKA3 in Endometrial Cancer and Its Promotion of Proliferation and Migration of Endometrial Cancer Cells

Background: Endometrial cancer is one of the common cancers in gynecology, which seriously endangers women’s reproductive health. Therefore, it is urgent to search for new diagnostic and prognostic monitoring markers for endometrial cancer. This study aimed to explore the clinical significance and biological role of spindle and kinetochore-associated complex subunit 3 (SKA3) in endometrial cancer. Methods: Weighted gene co-expression network analysis (WGCNA) and identification of differentially expressed genes (DEGs) were conducted to identify the key gene in endometrial cancer. The clinical significance of SKA3 within endometrial cancer was assessed through receiver operating characteristic (ROC) and Kaplan-Meier (KM) curves. Spearman correlation analysis, the STRING database, Cytoscape software, and the molecular complex detection (MCODE) algorithm were employed to investigate genes associated with SKA3. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were carried out for elucidating the functional role and pathways involving SKA3. The cBioPortal online platform was utilized to explore mutations in SKA3. The biological effects of SKA3 were further investigated through Cell Counting Kit-8 (CCK8) and cell scratch experiments. Results: SKA3 emerges as a pivotal gene in endometrial cancer, exhibiting a statistically significant high expression level. Its area under the curve (AUC) for diagnosing endometrial cancer stands at 0.943. Patients displaying elevated SKA3 expression demonstrated a notably poorer prognosis. In the context of endometrial cancer, 9 genes directly interact with SKA3. The functional pathway of SKA3 in endometrial cancer likely involves the mitotic pathway. The alterations observed in SKA3 in endometrial cancer primarily manifest as “mutations”. Specifically, SKA3 exhibits 26 mutation sites in endometrial cancer, distributed across 7 distinct regions and involving 4 mutation types. Furthermore, SKA3 is implicated in promoting the proliferation and migration of HEC-1A cells. Conclusion: SKA3, a key gene in endometrial cancer, holds significant diagnostic and prognostic value and may influence the progression in endometrial cancer.

Mechanisms and significance of spontaneous platelet aggregation in pathology

Platelets are unique blood elements that, in addition to blood coagulation, modulate the processes of fibrinolysis, inflammation, physiological regeneration, repair, angiogenesis, bone tissue formation, formation of the mother-placenta-fetus system, etc. Of particular interest is the phenomenon of spontaneous platelet aggregation in vivo under various physiological and pathological conditions, which is associated with expanded capabilities for assessing the risks of thrombotic events. A separate aspect of this problem is associated with the study of the mechanisms and biological role of reversible platelet aggregation. To date, the significance of this phenomenon under normal and pathological conditions remains not entirely clear. This review is devoted to the phenomenon of spontaneous reversible platelet aggregation, the modern understanding of its mechanisms, approaches to its diagnosis and its association with various pathological conditions.

Rational Molecular Design of a Fluorescent Probe for Selectively Sensing Human Cytochrome P450 2D6.

Cytochrome P450 2D6 (CYP2D6) is a key enzyme that mediates the metabolism of various drugs and endogenous substances in humans. However, its biological role in drug-drug interactions especially mechanism-based inactivation (MBI), and various diseases remains poorly understood, owing to the lack of molecular tools suitable for selectively monitoring CYP2D6 in complex biological systems. Herein, using a tailored molecular strategy, we developed a fluorescent probe BDPM for CYP2D6. BDPM exhibits excellent specificity and imaging capability for CYP2D6, making it suitable for the real-time monitoring of endogenous CYP2D6 activity in living bio-samples. Therefore, our tailored strategy proved useful for constructing the highly selective and enzyme-activated fluorescent probes. BDPM as a molecular tool to explore the critical roles of CYP2D6 in the pathogenesis of diseases, high-throughput screening of inhibitors and intensive investigation of CYP2D6-induced MBI in natural systems.

Protein localization and potential function of lipocalin in Reticulitermes speratus queens.

To understand the mechanisms underlying social evolution and caste development in social insects, caste-specific organs and genes should be investigated. In the rhinotermitid termite, Reticulitermes speratus, the lipocalin gene RS008881, which encodes a protein transporter, is expressed in the ovarian accessory glands of primary queens. To obtain additional data on its expression and product localization, we conducted real-time quantitative polymerase chain reaction and protein assays using a peptide antibody. Gene expression analysis of the castes revealed that RS008881 was highly expressed in female primary and secondary reproductives. Further analysis of its expression during reproductive caste differentiation showed that its expression levels increased prior to molting into reproductive individuals, even during the winged imago (alates) stage. Western blotting and fluorescent immunohistochemical staining revealed that the RS008881 product was localized in the ovary as well as the eggshells produced by female reproductives. RS008881 may play a significant role in the reproductive biology of R. speratus; protein localization in both the ovary and eggshell suggests multiple functions related to embryo protection and potential pheromone interactions.

Regulation of autophagy by non-coding RNAs in human glioblastoma.

Glioblastoma, a lethal form of brain cancer, poses substantial challenges in treatment due to its aggressive nature and resistance to standard therapies like radiation and chemotherapy. Autophagy has a crucial role in glioblastoma progression by supporting cellular homeostasis and promoting survival under stressful conditions. Non-coding RNAs (ncRNAs) play diverse biological roles including, gene regulation, chromatin remodeling, and the maintenance of cellular homeostasis. Emerging evidence reveals the intricate regulatory mechanisms of autophagy orchestrated by non-coding RNAs (ncRNAs) in glioblastoma. The diverse roles of these ncRNAs in regulating crucial autophagy-related pathways, including AMPK/mTOR signaling, the PI3K/AKT pathway, Beclin1, and other autophagy-triggering system regulation, sheds light on ncRNAs biological mechanisms in the proliferation, invasion, and therapy response of glioblastoma cells. Furthermore, the clinical implications of targeting ncRNA-regulated autophagy as a promising therapeutic strategy for glioblastoma treatment are in the spotlight of ongoing studies. In this review, we delve into our current understanding of how ncRNAs regulate autophagy in glioblastoma, with a specific focus on microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), and their intricate interplay with therapy response.

Revealing the Structure of Sheer N-Acetylglucosamine, an Essential Chemical Scaffold in Glycobiology.

We explored the conformational landscape of N-acetyl-α-d-glucosamine (α-GlcNAc), a fundamental chemical scaffold in glycobiology. Solid samples were vaporized by laser ablation, expanded in a supersonic jet, and characterized by broadband chirped pulse Fourier transform microwave spectroscopy. In the isolation conditions of the jet, three different structures of GlcNAc have been discovered. These are conclusively identified by comparing the experimental values of the rotational constants with those predicted by theoretical calculations. The conformational preferences are controlled by intramolecular hydrogen bond networks formed between the polar groups in the acetamido group and the hydroxyl groups and dominated in all cases by a strong OH···O═C interaction. We reported an exception to the gauche effect due to the enhanced stability observed for the Tg+ conformer. All the structures present the same disposition of the acetamido group, which explains the highly selective binding of N-acetylglucosamine with different amino acid residues. Thus, the comprehensive structural data provided here shall help to shed some light on the biological role of this relevant amino sugar.

Investigating Full-Length circRNA Transcripts to Reveal circRNAMediated Regulation of Competing Endogenous RNAs in Gastric Cancer

Background: Circular RNAs (circRNAs) play important regulatory roles in the progression of gastric cancer (GC), but the exact mechanisms governing their regulation remain incompletely understood. Prior studies typically used back-spliced junctions (BSJs) to represent a range of circRNA isoforms, overlooking the prevalence of alternative splicing (AS) events within circRNAs, which could lead to unreliable or even incorrect conclusions in subsequent analyses, hindering our comprehension of the specific functions of circRNAs in GC. Objective: This study aimed to explore the potential functional roles of the dysregulated circRNA transcripts in GC and provide new biomarkers and effective novel therapeutic strategies for GC treatment. Methods: RNA-seq data with rRNA depletion and RNase R treatment was employed to characterize the expression profiles of circRNAs in GC, and RNA-seq data only with rRNA depletion was employed to identify differentially expressed mRNAs in GC. Based on the full-sequence information and accurate isoform-level quantification of circRNA transcripts calculated by the CircAST tool, we performed a series of bioinformatic analyses. A circRNA-miRNA-hub gene regulatory network was constructed to reveal the circRNA-mediated regulation of competing endogenous RNAs in GC, and then the protein-protein interaction (PPI) network was built to identify hub genes. Results: A total of 18,398 circular transcripts were successfully reconstructed in the samples. Herein, 351 upregulated and 177 downregulated circRNA transcripts were identified. Functional enrichment analysis revealed that their parental genes were strongly associated with GC. After several screening steps, 19 dysregulated circRNA transcripts, 40 related miRNAs, and 65 target genes (mRNAs) were selected to construct the ceRNA network. Through PPI analysis, five hub genes (COL5A2, PDGFRB, SPARC, COL1A2, and COL4A1) were excavated. All these hub genes may play vital roles in gastric cancer cell proliferation and invasion. Conclusion: Our study revealed a comprehensive profile of full-length circRNA transcripts in GC, which could provide potential prognostic biomarkers and targets for GC treatment. The results would be helpful for further studies on the biological roles of circRNAs in GC and offer new mechanistic insights into the pathogenesis of GC.

NSUN2 regulates Wnt signaling pathway depending on the m5C RNA modification to promote the progression of hepatocellular carcinoma.

5-Methylcytosine (m5C) RNA modification is a highly abundant and important epigenetic modification in mammals. As an important RNA m5C methyltransferase, NOP2/Sun-domain family member 2 (NSUN2)-mediated m5C RNA modification plays an important role in the regulation of the biological functions in many cancers. However, little is known about the biological role of NSUN2 in hepatocellular carcinoma (HCC). In this study, we found that the expression of NSUN2 was significantly upregulated in HCC, and the HCC patients with higher expression of NSUN2 had a poorer prognosis than those with lower expression of NSUN2. NSUN2 could affect the tumor immune regulation of HCC in several ways. In vitro and in vivo experiments confirmed that NSUN2 knockdown significantly decreased the abilities of proliferation, colony formation, migration and invasion of HCC cells. The methylated RNA immunoprecipitation-sequencing (MeRIP-seq) showed NSUN2 knockdown significantly affected the abundance, distribution, and composition of m5C RNA modification in HCC cells. Functional enrichment analyses and in vitro experiments suggested that NSUN2 could promote the HCC cells to proliferate, migrate and invade by regulating Wnt signaling pathway. SARS2 were identified via the RNA immunoprecipitation-sequencing (RIP-Seq) and MeRIP-seq as downstream target of NSUN2, which may play an important role in tumor-promoting effect of NSUN2-mediated m5C RNA modification in HCC. In conclusion, NSUN2 promotes HCC progression by regulating Wnt signaling pathway and SARS2 in an m5C-dependent manner.

Exploring the Role of Sigma Receptors in the Treatment of Cancer: A Narrative Review.

This study investigated the association of sigma receptors (SRs) and their selective ligands (because the molecular characteristics of the same SRs, particularly sigma-2 receptor {S2R}, are not completely clear) in carcinogenesis, their potential use as antitumor agents, and their great utility in tumor imaging.The ion channels and transporters enhance the cell's ability to adapt to the metabolic conditions encountered in the tumor tissue. The high expression of SRs in the proliferating cells compared with those at rest indicates that this is a significant clinical biomarker for determining the proliferative status of solid tumors using functional PET imaging techniques. The association of SRs in the pathophysiology of cancer cells is a result of the high concentration of S1R and S2R binding sites observed in various tumor cell lines and tissues. It would also be remarkable to determine if SRs are involved in metastasis and other metastatic cell behaviorssuch as adhesion, secretion, motility, and penetration. An absolute challenge for research in this field is to develop an integrated model that describes the molecular mechanisms of sigma receptors, incorporating their known biological and pathophysiological roles.

Biological role of Semaphorin 6D in the proliferation, migration and invasion of gastric cancer

Background: To analyse how Semaphorin 6D (SEMA6D) expression and extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathways are activated and how they influence gastric cancer proliferation, migration, and invasion. Methodology: SEMA6D expression was knocked down in human gastric cancer cells using RNA interference technology. In vitro assays were used to analyse how SEMA6D knockdown affects clone formation, migration, and invasion. ERK and PI3K/ AKT/mTOR signaling pathway related proteins were detected by immunoblotting. Results: In the si-NC group, Sema6D protein levels were higher than those in the si-1 and si-2 groups after knockdown of Sema6D, while in the si-1 group, Sema6D protein levels were higher than those in the si-2 group (P&lt;0.05). P-PI3K, ERK/p-ERK, AKT/p-AKT, and mTOR/p-mTOR levels in the si-NC group were significantly higher than those in the si-1 and si-2 groups after knockdown of Sema6D (P &lt; 0.05). It was found that scratch healing rate of SGC-7901 cells in si-NC group was higher than that in si-1 and si-2 groups, and the difference was statistically significant (P &lt; 0.05). Conclusion: SEMA6D expression level can affect the biological behavior of gastric cancer cells. Keywords: Gastric cancer; extracellular signal-regulated kinase; semaphorin 6D; ERK and PI3K/AKT/mTOR; cell proliferation.

9304 Integration of Glucocorticoid and Mineralocorticoid Receptor Signaling in Triple-negative Breast Cancer Models

Abstract Disclosure: S. Posani: None. C.A. Lange: None. Glucocorticoid receptors (GR) sense a convergence of host and cellular stress signaling to orchestrate an array of advanced cancer phenotypes associated with triple-negative breast cancer (TNBC) progression. The Lange lab reported p38 MAP kinase mediated phosphorylation of GR at serine 134 (Ser134) in response to tumor microenvironment-derived cytokines, such as TGF-beta-1. Phospho-Ser134-GR (p-Ser134-GR) upregulated gene sets that promote cancer cell survival, chemoresistance, altered metabolism, and migratory/invasive behavior in TNBC models. In addition to acting as ligands for GR, glucocorticoids also bind to and activate another closely related steroid hormone receptor - the mineralocorticoid receptor (MR). The elucidation of functional responses upon activation of MR remains an untapped area in breast cancer research. Our probe into public datasets (METABRIC, and TCGA) demonstrated significantly higher expression of MR transcripts in TNBC relative to luminal breast cancer. High expression of MR predicted worse overall survival in ERα-negative breast cancer patients compared to the low expressing cohort. Silencing of MR was carried out by siRNA-mediated knockdown and treatment with spironolactone, a competitive MR antagonist. Interestingly, MR knockdown significantly reduced the TGF-beta-1 induced migratory capacity of breast cancer cells compared to the wild-type control cells expressing endogenous MR. This biological phenotype of decreased TGF-beta-1 induced migration upon MR knockdown parallels the reduced migration we observed when the p38 MAPK site (Ser134 on GR was mutated to Ala in TNBC models. We therefore hypothesized that MR and GR may cooperate under the influence stress signaling in response to growth factors and cytokines abundantly present in the tumor-microenvironment. Preliminary data suggest that cytoplasmic p-Ser134-GR/MR complexes associate upon TGF-beta-1 treatment, while GR and/or MR ligands stimulate the formation of nuclear GR/MR complexes. We are further investigating cytokine- and stress-signal mediated regulation of GR/MR complexes and their functional role in TNBC biology. The overarching goal of this study is to elucidate if MR is a required GR binding-partner and a potential therapeutic target in GR- and cytokine-driven metastatic TNBC processes. Presentation: 6/2/2024

7873 Integration Of Glucocorticoid And Mineralocorticoid Receptor Signaling In Triple-Negative Breast Cancer Models

Abstract Disclosure: S. Posani: None. C.A. Lange: None. Glucocorticoid receptors (GR) sense a convergence of host and cellular stress signaling to orchestrate an array of advanced cancer phenotypes associated with triple-negative breast cancer (TNBC) progression. The Lange lab reported p38 MAP kinase mediated phosphorylation of GR at serine 134 (Ser134) in response to tumor microenvironment-derived cytokines, such as TGF-beta-1. Phospho-Ser134-GR (p-Ser134-GR) upregulated gene sets that promote cancer cell survival, chemoresistance, altered metabolism, and migratory/invasive behavior in TNBC models. In addition to acting as ligands for GR, glucocorticoids also bind to and activate another closely related steroid hormone receptor - the mineralocorticoid receptor (MR). The elucidation of functional responses upon activation of MR remains an untapped area in breast cancer research. Our probe into public datasets (METABRIC, and TCGA) demonstrated significantly higher expression of MR transcripts in TNBC relative to luminal breast cancer. High expression of MR predicted worse overall survival in ERα-negative breast cancer patients compared to the low expressing cohort. Silencing of MR was carried out by siRNA-mediated knockdown and treatment with spironolactone, a competitive MR antagonist. Interestingly, MR knockdown significantly reduced the TGF-beta-1 induced migratory capacity of breast cancer cells compared to the wild-type control cells expressing endogenous MR. This biological phenotype of decreased TGF-beta-1 induced migration upon MR knockdown parallels the reduced migration we observed when the p38 MAPK site (Ser134 on GR was mutated to Ala in TNBC models. We therefore hypothesized that MR and GR may cooperate under the influence stress signaling in response to growth factors and cytokines abundantly present in the tumor-microenvironment. Preliminary data suggest that cytoplasmic p-Ser134-GR/MR complexes associate upon TGF-beta-1 treatment, while GR and/or MR ligands stimulate the formation of nuclear GR/MR complexes. We are further investigating cytokine- and stress-signal mediated regulation of GR/MR complexes and their functional role in TNBC biology. The overarching goal of this study is to elucidate if MR is a required GR binding-partner and a potential therapeutic target in GR- and cytokine-driven metastatic TNBC processes. Presentation: 6/2/2024

9304 Integration Of Glucocorticoid And Mineralocorticoid Receptor Signaling In Triple-Negative Breast Cancer Models

Abstract Disclosure: S. Posani: None. C.A. Lange: None. Glucocorticoid receptors (GR) sense a convergence of host and cellular stress signaling to orchestrate an array of advanced cancer phenotypes associated with triple-negative breast cancer (TNBC) progression. The Lange lab reported p38 MAP kinase mediated phosphorylation of GR at serine 134 (Ser134) in response to tumor microenvironment-derived cytokines, such as TGF-beta-1. Phospho-Ser134-GR (p-Ser134-GR) upregulated gene sets that promote cancer cell survival, chemoresistance, altered metabolism, and migratory/invasive behavior in TNBC models. In addition to acting as ligands for GR, glucocorticoids also bind to and activate another closely related steroid hormone receptor - the mineralocorticoid receptor (MR). The elucidation of functional responses upon activation of MR remains an untapped area in breast cancer research. Our probe into public datasets (METABRIC, and TCGA) demonstrated significantly higher expression of MR transcripts in TNBC relative to luminal breast cancer. High expression of MR predicted worse overall survival in ERα-negative breast cancer patients compared to the low expressing cohort. Silencing of MR was carried out by siRNA-mediated knockdown and treatment with spironolactone, a competitive MR antagonist. Interestingly, MR knockdown significantly reduced the TGF-beta-1 induced migratory capacity of breast cancer cells compared to the wild-type control cells expressing endogenous MR. This biological phenotype of decreased TGF-beta-1 induced migration upon MR knockdown parallels the reduced migration we observed when the p38 MAPK site (Ser134 on GR was mutated to Ala in TNBC models. We therefore hypothesized that MR and GR may cooperate under the influence stress signaling in response to growth factors and cytokines abundantly present in the tumor-microenvironment. Preliminary data suggest that cytoplasmic p-Ser134-GR/MR complexes associate upon TGF-beta-1 treatment, while GR and/or MR ligands stimulate the formation of nuclear GR/MR complexes. We are further investigating cytokine- and stress-signal mediated regulation of GR/MR complexes and their functional role in TNBC biology. The overarching goal of this study is to elucidate if MR is a required GR binding-partner and a potential therapeutic target in GR- and cytokine-driven metastatic TNBC processes. Presentation: 6/2/2024

8700 Mono(ADP-Ribosyl)ation of Ribosomal Proteins Promotes Differentiation During Adipogenesis

Abstract Disclosure: X. Tan: None. S. Challa: None. C.V. Camacho: None. T.S. Nandu: None. M.S. Stokes: None. W.L. Kraus: Other; Self; W.L.K. is a founder and stockholder for Ribon Therapeutics, Inc; a founder, member of the SAB, member of the BOD, and a stockholder for and ARase Therapeutics, Inc. He is also coholder of U.S. Patent. ADP-ribosylation, a crucial post-translational modification, involves the covalent attachment of ADP-ribose units to amino acids on proteins through ADP-ribosyl transferase (ART) enzymes, utilizing NAD+ synthesized by nicotinamide mononucleotide adenylyl transferases (NMNATs). We previously showed that NMNAT-2, a cytoplasmic NAD+ synthase, increases during adipogenesis, leading to reduced nuclear NAD+ levels through compartmentalized NMN depletion and enhanced differentiation of preadipocytes. However, the implications of increased cytoplasmic NAD+ synthesis by NMNAT-2 in adipocytes remain unknown. Our current findings demonstrate elevated ribosome MARylation during 3T3-L1 preadipocyte differentiation, driven by NMNAT-2 induction. Inhibiting NAD+ biosynthesis by knockdown of NMNAT-2 or FK866 results in reduced ribosome MARylation, with PARP16 identified as the primary ART mediating MARylation. Knockdown of NMNAT-2 or PARP16 impaired global protein synthesis and preadipocyte differentiation. Treatment with the PARP16 inhibitor DB008 hindered ribosomal MARylation and preadipocyte differentiation. Immunofluorescence and subcellular fractionation analysis demonstrated that MARylated ribosomes are mostly associated with the endoplasmic reticulum. Using TMT mass spectrometry, we identified numerous high-confidence ADP-ribosylation sites on glutamate and aspartate residues in both undifferentiated and differentiated cells. We examined five proteins with specific sites of MARylation that are consistently more modified in the differentiated state. Among these, ADP-ribosylation of RPSA significantly promote preadipocyte differentiation; mutation of the site inhibits this effect. Ongoing investigations involve studying the impact of Parp16 knockout on high fat diet-induced obesity in mice to further determine the biological role of ribosome protein MARylation during adipogenesis. This work is supported by a grant from the NIH/NIDDK (R01 DK069710) and the DOD OCRP (OC200311). Presentation: 6/1/2024