siRNA Targeting Research Articles

Oncogenic GNAS drives a pyloric-type transcriptomic program in pancreatic intraepithelial papillary mucinous neoplasms

BACKGROUND & AIMS: Intraductal Papillary Mucinous Neoplasms (IPMNs) are cystic lesions of the pancreas which can serve as precursors for pancreatic ductal adenocarcinoma (PDAC). Recently, we showed that acinar to ductal metaplasia (ADM), an injury repair program associated with pancreatic tumorigenesis, is characterized by a pyloric-type transcriptomic program similar to gastric spasmolytic polypeptide expressing metaplasia (SPEM), suggesting common mechanisms of reprogramming between the stomach and pancreas. The aims of this study were to assay IPMN for SPEM markers and to identify molecular drivers of this program. METHODS: Published RNA-seq studies of IPMN were assessed for SPEM markers, which were validated by immunostaining in patient samples. Murine cell lines expressing KrasG12D +/- GNASR201C were manipulated to identify distinct and overlapping transcriptomic programs driven by each oncogene. A PyScenic-based regulon analysis was performed to identify drivers of SPEM in the pancreas. Expression of candidate drivers was evaluated in patient samples by RNA-seq and immunostaining and a role for SPDEF was investigated. RESULTS: SPEM markers were identified in human IPMN. GNASR201C drove expression of these markers in murine cell lines and siRNA targeting of GNASR201C or KrasG12D demonstrates that GNASR201C amplifies a mucinous phenotype. Regulon analysis identified a role for transcription factors SPDEF, CREB3L1, and CREB3L4, which are expressed in patient samples. CONCLUSIONS: De novo expression of a pyloric-type/SPEM phenotype has been identified in pancreatitis, oncogenic KrasG12D-driven pancreatic neoplasia, and in KrasG12D;GNASR201C-driven IPMN, suggesting common mechanisms of reprogramming between these lesions and the stomach. IPMN-specific GNASR201C drives a SPEM phenotype characterized by the formation of mucus producing cells at the expense of other lineages. AMR was supported by NIH T32GM139400. AM is supported by the MD Anderson Pancreatic Cancer Moon Shot Program, the Sheikh Khalifa Bin Zayed Al-Nahyan Foundation and NIH (U01CA200468, U54CA274371, U24CA274274, R01CA220236). M.C.B.T is supported by a Vanderbilt Digestive Disease Research Center Pilot and Feasibility Grant (P30 DK058404) and a Nikki Mitchell Foundation Pancreas Club Seed Grant. M.C.B.T and N.J. are supported by The Department of Defense (DOD W81XWH2211121-1). The DelGiorno laboratory is supported by the Vanderbilt Ingram Cancer Center Support Grant (NIH/NCI P30 CA068485), the Vanderbilt-Ingram Cancer Center SPORE in Gastrointestinal Cancer (NIH/NCI 5P50 CA236733), the Vanderbilt Digestive Disease Research Center (NIH/NIDDK P30 DK058404), an American Gastroenterological Association Research Scholar Award (AGA2021-13-02), NIH/NIGMS R35 GM142709, The Department of Defense (DOD W81XWH2211121), The Sky Foundation, Inc (AWD00000079), and Linda’s Hope (Nashville, TN). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

MCT4 knockdown by tumor microenvironment-responsive nanoparticles remodels the cytokine profile and eradicates aggressive breast cancer cells

Breast cancer is a wide-spread threat to the women’s health. The drawbacks of conventional treatments necessitate the development of alternative strategies, where gene therapy has regained hope in achieving an efficient eradication of aggressive tumors. Monocarboxylate transporter 4 (MCT4) plays pivotal roles in the growth and survival of various tumors, which offers a promising target for treatment. In the present study, pH-responsive lipid nanoparticles (LNPs) based on the ionizable lipid,1,2-dioleoyl-3-dimethylammonium propane (DODAP), were designed for the delivery of siRNA targeting MCT4 gene to the breast cancer cells. Following multiple steps of characterization and optimization, the anticancer activities of the LNPs were assessed against an aggressive breast cancer cell line, 4T1, in comparison with a normal cell line, LX-2. The selection of the helper phospholipid to be incorporated into the LNPs had a dramatic impact on their gene delivery performance. The optimized LNPs enabled a powerful MCT4 silencing by ∼90 % at low siRNA concentrations, with a subsequent ∼80 % cytotoxicity to 4T1 cells. Meanwhile, the LNPs demonstrated a 5-fold higher affinity to the breast cancer cells versus the normal cells, in which they had a minimum effect. Moreover, the MCT4 knockdown by the treatment remodeled the cytokine profile in 4T1 cells, as evidenced by 90 % and ∼64 % reduction in the levels of TNF-α and IL-6; respectively. The findings of this study are promising for potential clinical applications. Furthermore, the simple and scalable delivery vector developed herein can serve as a breast cancer-targeting platform for the delivery of other RNA therapeutics.

PTIP UFMylation promotes replication fork degradation in BRCA1-deficient cells

“BRCAness” defines cancers that are homologous recombination (HR)-deficient due to BRCA1 or BRCA2 mutations. These mutations confer synthetic lethality with PARP1/2 inhibitors. The chromatin regulator PTIP promotes stalled replication fork degradation in “BRCAness” cells, but the underlying mechanism by which PTIP regulates stalled replication fork stability is unclear. Here, we performed a series of in vitro analyses to dissect the function of UFMylation in regulating fork stabilization in BRCA1-deficient cells. By denaturing co-immunoprecipitation, we first found that replication stress can induce PTIP UFMylation. Interestingly, this post-translational modification promotes end resection and degradation of nascent DNA at stalled replication forks in BRCA1-deficient cells. By cell viability assay, we found that PTIP-depleted and UFL1-depleted BRCA1 knockdown cells are less sensitive to PARP inhibitors than the siRNA targeting negative control BRCA1-deficient cells. These results identify a new mechanism by which PTIP UFMylation confers chemoresistance in BRCA1-deficient cells.

Investigating Novel Therapeutic Approaches for Idiopathic Short Stature: Targeting siRNA and Growth Hormone Delivery to the Growth Plate Using Exosome Nanoparticles.

Idiopathic short stature (ISS) is a common childhood condition with largely unknown underlying causes. Recent research highlights the role of circulating exosomes in the pathogenesis of various disorders, but their connection to ISS remains unexplored. In the experiments, human chondrocytes are cocultured with plasma exosomes from ISS patients, leading to impaired chondrocyte growth and bone formation. Elevated levels of a specific long non-coding RNA (lncRNA), ISSRL, are identified as a distinguishing factor in ISS, boasting high specificity and sensitivity. Silencing ISSRL in ISS plasma exosomes reverses the inhibition of chondrocyte proliferation and bone formation. Conversely, overexpression of ISSRL in chondrocytes impedes their growth and bone formation, revealing its mechanism of action through the miR-877-3p/GZMB axis. Subsequently, exosomes (CT-Exo-siISSRL-oeGH) with precise cartilage-targeting abilities are engineered, loaded with customized siRNA for ISSRL and growth hormone. This innovative approach offers a therapeutic strategy to address ISS by rectifying abnormal non-coding RNA expression in growth plate cartilage and delivering growth hormone with precision to promote bone growth. This research provides valuable insights into ISS diagnosis and treatment, highlighting the potential of engineered exosomes.

Herb Extracellular Vesicle-Chitosan-PEGylated Graphene Oxide Conjugate Delivers Estrogen Receptor α Targeting siRNA to Breast Cancer Cells.

Herb-based extracellular vesicles (EV), inherently replete with bioactive proteins, RNA, lipids, and other medicinal compounds, are noncytotoxic and uniquely capable of cellular delivery to meet the ever-stringent challenges of ongoing clinical applications. EVs are abundant in nature, affordable, and scalable, but they are also incredibly fragile and stuffed with many biomolecules. To address the low drug binding abilities and poor stability of EVs, we demonstrated herb-based EVs (isolated from neem, mint, and curry leaves) conjugated with chitosan (CS) and PEGylated graphene oxide (GP) that led to their transformation into robust and efficient vectors. The designed conjugates successfully delivered estrogen receptor α (ERα1)-targeting siRNA to breast cancer MCF7 cells. Our data revealed that neem-based EV-CS-GP conjugates were most efficient in cellular siRNA delivery, which could be attributed to hyaluronic acid-mediated recognition of neem EVs by MCF7 cells via CD44 receptors. Our approach shows a futuristic direction in designing clinically viable, sustainable, nontoxic EV-based vehicles that can deliver a variety of functional siRNA cargos.

Lipid nanoparticle mediated small interfering RNA delivery as a potential therapy for Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative condition that exhibits a gradual decline in cognitive function and is prevalent among a significant number of individuals globally. The use of small interfering RNA (siRNA) molecules in RNA interference (RNAi) presents a promising therapeutic strategy for AD. Lipid nanoparticles (LNPs) have been developed as a delivery vehicle for siRNA, which can selectively suppress target genes, by enhancing cellular uptake and safeguarding siRNA from degradation. Numerous research studies have exhibited the effectiveness of LNP-mediated siRNA delivery in reducing amyloid beta (Aβ) levels and enhancing cognitive function in animal models of AD. The feasibility of employing LNP-mediated siRNA delivery as a therapeutic approach for AD is emphasized by the encouraging outcomes reported in clinical studies for other medical conditions. The use of LNP-mediated siRNA delivery has emerged as a promising strategy to slow down or even reverse the progression of AD by targeting the synthesis of tau phosphorylation and other genes linked to the condition. Improvement of the delivery mechanism and determination of the most suitable siRNA targets are crucial for the efficacious management of AD. This review focuses on the delivery of siRNA through LNPs as a promising therapeutic strategy for AD, based on the available literature.

Knockdown siRNA Targeting GPR55 Reveals Significant Differences Between the Anti-inflammatory Actions of KLS-13019 and Cannabidiol.

KLS-13019 was reported previously to reverse paclitaxel-induced mechanical allodynia in a mouse model of chemotherapy-induced peripheral neuropathy (CIPN). Recent studies demonstrated that paclitaxel-induced increases in inflammatory markers (GPR55, NLRP3, and IL-1β) of dorsal root ganglion (DRG) cultures were shown to be reversed by KLS-13019 treatment. The mechanism of action for KLS-13019-mediated reversal of paclitaxel-induced neuroinflammation now has been explored using GPR55 siRNA. Pre-treatment of DRG cultures with GPR55 siRNA produced a 21% decrease of immunoreactive (IR) area for GPR55 in cell bodies and a 59% decrease in neuritic IR area, as determined by high-content imaging. Using a 24-h reversal treatment paradigm, paclitaxel-induced increases in the inflammatory markers were reversed back to control levels after KLS-3019 treatment. Decreases in these inflammatory markers produced by KLS-13019 were significantly attenuated by GPR55 siRNA co-treatment, with mean IR area responses being attenuated by 56% in neurites and 53% in cell bodies. These data indicate that the percentage decreases in siRNA-mediated attenuation of KLS-13019-related efficacy on the inflammatory markers were similar to the percentage knockdown observed for neuritic GPR55 IR area. Similar studies conducted with cannabidiol (CBD), the parent compound of KLS-13019, produced low efficacy (25%) reversal of all inflammatory markers that were poorly attenuated (29%) by GPR55 siRNA. CBD was shown previously to be ineffective in reversing paclitaxel-induced mechanical allodynia. The present studies indicated significant differences between the anti-inflammatory properties of KLS-13019 and CBD which may play a role in their observed differences in the reversibility of mechanical allodynia in a mouse model of CIPN.

SiRNA-Mediated Knockdown of ABCB1 Enhances the Efficacy of Doxorubicin and Vinorelbine in Breast Cancer Cells.

Breast cancer remains a leading cause of cancer-related deaths among women, primarily attributed to the formidable challenge of multidrug resistance, often driven by the overexpression of the ABCB1 gene. This study aimed to assess the synergistic effects of siRNA, doxorubicin, and vinorelbine on ABCB1 gene expression and cell viability in doxorubicin-resistant MCF-7/ADR breast cancer cells, with siRNA targeting ABCB1 to reduce its expression and doxorubicin/ vinorelbine to eradicate cancer cells. Our methodology involved culturing MCF-7 and MCF-7/ADR cells in standard cell culture conditions. The synthesized siRNA sequences transfected cells with siRNA at final concentrations of 10, 20, and 30 nM and assessed cell viability using the MTT assay was performed. Real-time PCR was employed to quantify ABCB1 mRNA expression levels. Results indicated that MCF-7/ADR cells exhibited substantial resistance to vinorelbine and doxorubicin compared to MCF-7 cells, displaying resistance at 12.50 μM and 25.00 μM for vinorelbine and 6.25 μM and 25.00 μM for doxorubicin. Remarkably, siRNA treatment effectively reversed drug resistance in MCF-7/ADR cells across all concentrations of vinorelbine and doxorubicin tested. When combined, siRNA, doxorubicin, and vinorelbine yielded a significantly greater reduction in cell viability compared to individual drug treatments, particularly at a 20 μM siRNA concentration. This combination therapy also significantly suppressed ABCB1 gene expression by a factor of 41.48 in MCF-7 cells relative to MCF-7/ADR cells. these findings suggest that combining siRNA, doxorubicin, and vinorelbine holds promise as a therapeutic strategy to overcome ABCB1-mediated multidrug resistance in breast cancer. Further investigations and clinical trials are warranted to evaluate its clinical efficacy rigorously.

Single-cell transcriptomics reveals the intra-tumoral heterogeneity and SQSTM1/P62 and Wnt/β-catenin mediated epithelial to mesenchymal transition and stemness of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is characterized by the complex tumor microenvironment (TME) consisting of an abundance of mesenchymal stem cells (MSCs), which is known to facilitate epithelial-to-mesenchymal transition (EMT). The development of single-cell genomics is a powerful method for defining the intricate genetic landscapes of malignancies. In this study, we have employed single-cell RNA sequencing (scRNA-seq) to dissect the intra-tumoral heterogeneity and analyze the single-cell transcriptomic landscape to detect rare consequential cell subpopulations of significance. The scRNA-seq analysis of TNBC and Normal patient derived samples revealed that EMT markers and transcription factors were most upregulated in MSC population. Further, exploration of gene expression analysis among TNBC and Normal patient-derived MSCs ascertained the role of SQSTM1/P62 and Wnt/β-catenin in TNBC progression. Wnt/β-catenin and Wnt/PCP signaling pathways are prominent contributors of EMT, stemness, and cancer stem cell (CSC) properties of TNBC. SQSTM1/P62 cooperates with the components of the Wnt/PCP signaling pathway and is critically involved at the interface of autophagy and EMT.Moreover, siRNA targeting SQSTM1/P62 and inhibitor of Wnt/β-catenin (FH535) in conjunction was used to explore molecular modification of EMT and stemness markers. Although SQSTM1/P62 is not crucial for cell survival, cytotoxicity assay revealed synergistic interaction between the siRNA/inhibitor. Modulation of these important pathways helped in reduction of expression of genes and proteins contributing to CSC properties. Gene and protein expression analysis revealed the induction of EMT to MET. Moreover, co-treatment resulted in inactivation of non-canonical Wnt VANGL2-JNK signaling axis. The synergistic impact of inhibition of SQSTM1/P62 and Wnt/β-catenin signaling facilitates the development of a potential therapeutic regimen for TNBC.

Abstract LB450: Mechanisms of acquired resistance to AKT inhibitor capivasertib in AKT1 mutant patient derived breast cancer models

Abstract Capivasertib, a pan-AKT inhibitor, has recently been approved in combination with fulvestrant to treat ER+ HER2- breast cancer patients with one or more of PI3KCA/AKT1/PTEN alterations. However, as with many targeted therapies acquired drug resistance remains a challenge. In this study, we investigated the mechanisms of acquired capivasertib resistance in AKT1 mutant breast cancer models. We established two estrogen receptor positive (ER+) AKT1 E17K mutant breast cancer patient derived organoids (PDOs), that were sensitive to capivasertib in vitro. PDOs were chronically exposed to 1µM capivasertib. PDOs were sequenced (DNA & RNA) at multiple timepoints of treatment (3 days, 4 and 9 weeks after development of resistance). Using CRISPR-Cas9 editing we also engineered CAMA1 (ER+) cells to express AKT1 E17K, and generated derived resistant AKT1 mutant and parental models in response to continuous capivasertib exposure. CAMA1 AKT1 mutant and parental resistant were screened with an siRNA Kinome library supplemented with genes from the PDO RNA-sequencing. Phosphoproteomics was performed on capivasertib resistant E17K models in the presence and absence of capivasertib. PDO models persisting after either 4 or 9 weeks of capivasertib treatment showed no acquisition of genetic driver events, or changes in AKT copy number. Resistant organoids at 9 weeks treatment showed increased expression of ERBB3 (HER3), EGFR3 and LPAR5 as well as increased expression of MAPK signalling components. In siRNA screens on CAMA1 derived resistant models, siRNA targeting ERBB2, CDK4, PLK4 and CHEK1, ESR1 and LPAR5 modulated sensitivity to capivasertib. Analysis of phosphoproteins in capivasertib resistant models revealed reactivation of mTORC1 signalling despite sustained AKT inhibition, with dramatic upregulation of PDK1 and mTORC2. Consistent with the siRNA screens, drug combinations identified fulvestrant as a synergistic agent with capivasertib in the resistant E17K models. Sensitivity to mTOR inhibition was maintained in capivasertib resistant models, with mTOR inhibition re-sensitizing cells to capivasertib. In these models, acquired resistance to capivasertib occurs through upregulation of ER signalling and rewiring of pathway signalling to bypass AKT inhibition and reactivate mTORC1. Targeting these mechanisms could prolong the use of capivasertib, with future work focusing on validating these mechanisms and re-sensitizing drug combinations in other AKT1 mutant models & PDOs. Citation Format: Sarah Mearns, Alex Pearson, Li-Xuan Sim, Rosalind Cutts, Prithika Sritharan, Heena Shah, Aditi Gulati, Stuart Williamson, Simon Barry, Elza De-Bruin, Nicholas C. Turner. Mechanisms of acquired resistance to AKT inhibitor capivasertib in AKT1 mutant patient derived breast cancer models [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 LB450.

Arginine alleviates Clostridium perfringens α toxin-induced intestinal injury in vivo and in vitro via the SLC38A9/mTORC1 pathway.

Clostridium perfringens α toxin is a main virulence factor responsible for gut damage in animals. Arginine is a functional amino acid exhibiting significant immunoregulatory activities. However, the effects and immunoregulatory mechanisms of arginine supplementation on α toxin-induced intestinal injury remain unclear. In vivo, 256 male Arbor Acres chickens were randomly assigned to a 2×2 factorial arrangement, involving diet treatments (with or without 0.3% arginine supplementation) and immunological stress (with or without α toxin challenge). In vitro, IEC-6 cells were treated with or without arginine in the presence or absence of α toxin. Moreover, IEC-6 cells were transfected with siRNA targeting mTOR and SLC38A9 to explore the underlying mechanisms. The results showed that in vivo, arginine supplementation significantly alleviated the α toxin-induced growth performance impairment, decreases in serum immunoglobulin (Ig)A and IgG levels, and intestinal morphology damage. Arginine supplementation also significantly reduced the α toxin-induced increase in jejunal proinflammatory cytokines interleukin (IL)-1β, IL-6 and IL-17 mRNA expression. Clostridium perfringens α toxin significantly decreased jejunal mechanistic target of rapamycin (mTOR) and solute carrier family 38 member 9 (SLC38A9) mRNA expression, while arginine supplementation significantly increased mTOR and SLC38A9 mRNA expression. In vitro, arginine pretreatment mitigated the α toxin-induced decrease in cell viability and the increase in cytotoxicity and apoptosis. Arginine pretreatment also alleviated the α toxin-induced upregulation of mRNA expression of inflammation-related cytokines IL-6, C-X-C motif chemokine ligand (CXCL)10, CXCL11 and transforming growth factor-β (TGF-β), as well as apoptosis-related genes B-cell lymphoma-2 associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), B-cell lymphoma-extra large (Bcl-XL) and cysteinyl aspartate specific proteinase 3 (Caspase-3) and the ratio of Bax to Bcl-2. Arginine pretreatment significantly increased the α toxin-induced decrease in mTOR, SLC38A9, eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4EBP1) and ribosomal protein S6 kinase (S6K) mRNA expression. Knockdown SLC38A9 and mTOR largely abrogated the positive effects of arginine pretreatment on α toxin-induced intracellular changes. Furthermore, SLC38A9 silencing abolished the increased mTOR mRNA expression caused by arginine pretreatment. In conclusion, arginine administration attenuated α toxin-induced intestinal injury in vivo and in vitro, which could be associated with the downregulation of inflammation via regulating SLC38A9/mTORC1 pathway.

Tetramethylpyrazine Nitrone Promotes the Clearance of Alpha-Synuclein via Nrf2-Mediated Ubiquitin-Proteasome System Activation.

Aggregation of α-synuclein (α-syn) and α-syn cytotoxicity are hallmarks of sporadic and familial Parkinson's disease (PD). Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent enhancement of the expression of the 20S proteasome core particles (20S CPs) and regulatory particles (RPs) increases proteasome activity, which can promote α-syn clearance in PD. Activation of peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) may reduce oxidative stress by strongly inducing Nrf2 gene expression. In the present study, tetramethylpyrazine nitrone (TBN), a potent-free radical scavenger, promoted α-syn clearance by the ubiquitin-proteasome system (UPS) in cell models overexpressing the human A53T mutant α-syn. In the α-syn transgenic mice model, TBN improved motor impairment, decreased the products of oxidative damage, and down-regulated the α-syn level in the serum. TBN consistently up-regulated PGC-1α and Nrf2 expression in tested models of PD. Additionally, TBN similarly enhanced the proteasome 20S subunit beta 8 (Psmb8) expression, which is linked to chymotrypsin-like proteasome activity. Furthermore, TBN increased the mRNA levels of both the 11S RPs subunits Pa28αβ and a proteasome chaperone, known as the proteasome maturation protein (Pomp). Interestingly, specific siRNA targeting of Nrf2 blocked TBN's effects on Psmb8, Pa28αβ, Pomp expression, and α-syn clearance. In conclusion, TBN promotes the clearance of α-syn via Nrf2-mediated UPS activation, and it may serve as a potentially disease-modifying therapeutic agent for PD.

Huanglian Jiedu decoction inhibits vascular smooth muscle cell-derived foam cell formation by activating autophagy via suppressing P2RY12

Ethnopharmacological relevanceHuanglian Jiedu Decoction (HLJDD) is a Chinese medicine with a long history of therapeutic application. It is widely used in treating atherosclerosis (AS) in Chinese medicine theory and clinical practice. However, the mechanism of HLJDD in treating AS remains unclear. Aim of the studyTo investigate the efficacy and mechanism of HLJDD in treating AS. Materials and methodsAS was induced on high-fat diet-fed ApoE−/− mice, with the aorta pathological changes evaluated with lipid content and plaque progression. In vitro, foam cells were induced by subjecting primary mouse aortic vascular smooth muscle cells (VSMCs) to oxLDL incubation. After HLJDD intervention, VSMCs were assessed with lipid stack, apoptosis, oxidative stress, and the expression of foam cell markers. The effects of P2RY12 were tested by adopting clopidogrel hydrogen sulfate (CDL) in vivo and transfecting P2RY12 over-expressive plasmid in vitro. Autophagy was inhibited by Chloroquine or transfecting siRNA targeting ATG7 (siATG7). The mechanism of HLJDD treating atherosclerosis was explored using network pharmacology and validated with molecular docking and co-immunoprecipitation. ResultsHLJDD exhibited a dose-dependent reduction in lipid deposition, collagen loss, and necrosis within plaques. It also reversed lipid accumulation and down-regulated the expression of foam cell markers. P2RY12 inhibition alleviated AS, while P2RY12 overexpression enhanced foam cell formation and blocked the therapeutic effects of HLJDD. Network pharmacological analysis suggested that HLJDD might mediate PI3K/AKT signaling pathway-induced autophagy. P2RY12 overexpression also impaired autophagy. Similarly, inhibiting autophagy counteracted the effect of CDL, exacerbated AS in vivo, and promoted foam cell formation in vitro. However, HLJDD treatment mitigated these detrimental effects by suppressing the PI3K/AKT signaling pathway. Immunofluorescence and molecular docking revealed a high affinity between P2RY12 and PIK3CB, while co-immunoprecipitation assays illustrated their interaction. ConclusionsHLJDD inhibited AS in vivo and foam cell formation in vitro by restoring P2RY12/PI3K/AKT signaling pathway-suppressed autophagy. This study is the first to reveal an interaction between P2RY12 and PI3K3CB.

Fibronectin binds integrin α5β1 to regulate macular neovascularization through the Wnt/β-catenin signaling pathway

Age-related macular degeneration (AMD) is a progressive, degenerative disease of the macula. The formation of macular neovascularization (MNV) and subretinal fibrosis of AMD is the most classic cause of the loss of vision in older adults worldwide. While the underlying causes of MNV and subretinal fibrosis remain elusive, the common feature of many common retinal diseases is changes the proportions of protein deposition in extracellular matrix (ECM) when compared to normal tissue. In ECM, fibronectin (FN) is a crucial component and plays a pivotal part not only in fibrotic diseases but also in the process of angiogenesis. The study aims to understand the role of ligand FN and its common integrin receptor α5β1 on MNV, and to understand the molecular mechanism involved. To study this, the laser-induced MNV mouse model and the rhesus macaque choroid-retinal endothelial cell line (RF/6A) chemical hypoxia mode were established, and the FN-α5β1 expression levels were detected by immunohistochemistry (IHC) and quantitative real-time PCR analysis (qRT-PCR). Fibronectin expression was silenced using small interfering RNA (siRNA) targeting FN. The tube formation and vitro scratch assays were used to assess the ability to form blood vessels and cell migration. To measure the formation of MNV, immunofluorescence, and Western blot assays were used. These results revealed that the expressions of FN and integrin α5β1 were distinctly increased in the laser-induced MNV mouse model and in the RF/6A cytochemically induced hypoxia model, and the expression tendency was identical. After the use of FN siRNA, the tube formation and migration abilities of the RF/6A cells were lower, the ability of endothelial cells to proliferate was confined and the scope of damage caused by the laser in animal models was significantly cut down. In addition, FN gene knockdown dramatically inhibited the expression of Wnt/β-catenin signal. The interaction of FN with the integrin receptor α5β1 in the constructed model, which may act through the Wnt/β-catenin signaling pathway, was confirmed in this study. In conclusion, FN may be a potential new molecular target for the prevention and treatment of subretinal fibrosis and MNV.

DEAD Box Helicase 24 Is Increased in the Brain in Alzheimer's Disease and AppN-LF Mice and Influences Presymptomatic Pathology.

At the time of diagnosis, Alzheimer's disease (AD) patients already suffer from significant neuronal loss. The identification of proteins that influence disease progression before the onset of symptoms is thus an essential part of the development of new effective drugs and biomarkers. Here, we used an unbiased 18O labelling proteomics approach to identify proteins showing altered levels in the AD brain. We studied the relationship between the protein with the highest increase in hippocampus, DEAD box Helicase 24 (DDX24), and AD pathology. We visualised DDX24 in the human brain and in a mouse model for Aβ42-induced AD pathology-AppNL-F-and studied the interaction between Aβ and DDX24 in primary neurons. Immunohistochemistry in the AD brain confirmed the increased levels and indicated an altered subcellular distribution of DDX24. Immunohistochemical studies in AppNL-F mice showed that the increase of DDX24 starts before amyloid pathology or memory impairment is observed. Immunocytochemistry in AppNL-F primary hippocampal neurons showed increased DDX24 intensity in the soma, nucleus and nucleolus. Furthermore, siRNA targeting of DDX24 in neurons decreased APP and Aβ42 levels, and the addition of Aβ42 to the medium reduced DDX24. In conclusion, we have identified DDX24 as a protein with a potential role in Aβ-induced AD pathology.

Abstract 5753: Milk-derived extracellular nanovesicles: A novel delivery strategy for transcriptome targeting therapies in cholangiocarcinoma

Abstract Introduction: Cholangiocarcinoma (CCA) is an aggressive and heterogenous biliary malignancy. Previous therapeutic shortcomings have encouraged the investigation of new strategies, such as targeted therapeutics. YAP/TAZ, transcriptional coactivators of the hippo pathway, have been implicated in the tumorigenesis of CCA along with the Src familiar kinase, LCK. Milk-derived nanovesicles (MNVs) have emerged as a promising biologic delivery apparatus for hepatobiliary malignancy due to their predilection for hepatic uptake. We sought to investigate the utility of aptamer guided MNVs loaded with short interfering RNA (siRNA) targeting YAP, TAZ, and LCK. Methods: MNVs were prepared and loaded with species-specific siRNA prior to decoration with an epithelial cellular adhesion molecule (EpCAM) targeting aptamer. In vitro studies were performed using murine and human CCA cell lines, SB1 and HuCCT-1, respectively. In vivo studies were carried out using C57BL/6 mice following Institutional Animal Care and Use Committee protocols. Results: We previously validated EpCAM as an effective aptamer demonstrated by increased levels of expression in CCA cell lines using immunoblot, RT-PCR and immunofluorescence. Additionally, in vivo experiments demonstrated excellent biodistribution and affinity for tumor-selective uptake. To evaluate knockdown efficacy, CCA cell lines were incubated with EpCAM aptamer guided MNVs individually targeting YAP, TAZ, and LCK which resulted in downregulation of these targets on immunoblot and RT-PCR. MNVs were then loaded with equal concentrations of siRNA targeting YAP, TAZ, and LCK in combination which resulted in similar degrees of gene downregulation compared with single transcriptome targeting MNVs. Due to the role of YAP/TAZ activation in CCA systemic therapy resistance, we investigated the effect of MNVs loaded with either single target or combinatory target siRNA alongside and in combination with gemcitabine and cisplatin (GemCis). Incubation with both combinatory siRNA and GemCis significantly intensified cell death on Pi/Hoechst staining compared with single target knockdown alone. Similar findings were found using separate assays of cell viability, including ATP luminescent quantitation and caspase 3/7 activity. These data suggest MNV transcriptome targeting may induce a state of cell stress which allows for amplification of chemotherapy treatment effect. Conclusion: Aptamer guided, nanovesicle mediated transcriptome targeting is a promising therapeutic strategy in preclinical CCA models that may potentiate chemotherapy response. Our future direction involves further investigating the role of CCA target downregulation and its effect on the tumor immune microenvironment utilizing aptamer guided nanovesicle delivery and inducible knockdown cell lines. Citation Format: Jack W. Sample, Mincheng Yu, Hendrien Kuipers, Danielle M. Carlson, Nathan W. Werneberg, Jennifer L. Tomlinson, Gregory J. Gores, Rory L. Smoot. Milk-derived extracellular nanovesicles: A novel delivery strategy for transcriptome targeting therapies in cholangiocarcinoma [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 5753.

Abstract 5860: Understanding the biological role of MMP16 in cisplatin resistance in ovarian cancer

Abstract High-Grade Serous Ovarian Cancer (HGSOC) is the most common and lethal of Ovarian Cancer (OC) types, which accounts for eighty percent of deaths. Treatment for OC includes surgery and platinum-based therapy. However, around 70% of women with HGSOC become resistant to chemotherapy. Therefore, new therapeutic agents with higher specificity and efficacy are needed for women with advanced and drug-resistant OC. Matrix metalloproteases (MMPs) are a group of enzymes involved in the degradation of the extracellular matrix (ECM). Deregulation of MMPs contributes to tumor growth and metastasis in several cancer types. Preliminary studies of our research team found that MMP16 is higher in cisplatin-resistant as compared with cisplatin-sensitive OC cells. The aim of this project is to understand the role of MMP16 in the cisplatin resistance of OC cells. We hypothesize that MMP16 increased expression may contribute to cancer progression and drug-resistance. We performed experiments in A2780/A2780CP20 and OVCAR3/OVCAR3CIS human OC cells. To assess the MMP16 protein levels we used western blot analysis. To measure the mRNA levels, we used qRT-PCR. Kaplan-Meier survival curves were generated by interrogation of the KM Plotter patient database. The MMP16 protein and qRT-PCR experiments confirmed that protein and mRNA levels are more abundant in cisplatin-resistant as compared with cisplatin-sensitive cells. Interrogation of the KM plotter database showed that OC patients with higher MMP16 mRNA levels live less as compared with OC patients with lower MMP16 levels. Ongoing experiments are testing the biological effect of small interference RNA (siRNA) targeting MMP16 in cisplatin-resistant OC cells. Citation Format: Jesennia Bonilla-Liriano, Mariela Rivera-Serrano, Victor Reyes-Burgos, Jose Rolon-Perez, Fatima Valiyeva, Pablo Vivas-Mejia. Understanding the biological role of MMP16 in cisplatin resistance in ovarian 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 5860.

Abstract 7150: Molecular insights into the oncogenic influence between mutant HER3, mutant KRAS, and their synergistic interplay in colorectal cancer pathogenesis

Abstract Colorectal cancer (CRC) is a disease of the colon and rectum that will claim about 52,550 American lives in 2023. In recent years, more attention has been paid to HER2 and HER3’s roles in colorectal cancers, as they may cause resistance to targeted therapies. We are investigating the role of naturally co-occurring HER3 and KRAS mutations in colorectal cancer, as about 6% of all colorectal cancers contain a HER3 mutation and 41% contain a KRAS mutation. We have observed that there is a statistically significant co-occurrence of HER3 and KRAS mutations in CRCs while there is mutual exclusivity with mutations in EGFR or HER4 and mutant KRAS in CRC examining 6791 samples from 17 studies. There is a tendency for co-occurrence with HER2 and KRAS mutations that is not statistically significant in these CRC tumor samples. We have found that genetic knockdown of both KRAS and HER3 with siRNA targeting KRAS and HER3 in the CRC cell line SNU-407 (HER3V104M, KRASG12D) results in a statistical reduction in cell proliferation in comparison to genetic knockdown with only KRAS or HER3. Using the SW620 CRC cell line (HER3WT, KRASG12V) as a comparison, we have observed that knocking down HER3 using siRNA had no effect on cell proliferation whereas KRAS knockdown reduced proliferation and the combination showed no statistical difference compared to knocking down only KRAS. Additionally, we have found that there is a striking increase in total HER3 levels in SNU-407 cells when treated with the KRASG12D inhibitor MRTX1133. This feedback loop could limit the efficacy of the KRAS inhibitor. We wished to delineate mutant HER3’s binding partner(s) as HER3 is kinase impaired. Strikingly, we have found that EGFR immunoprecipitates with HER3 in SNU-407 cells. We are expanding our studies to CRC patient derived xenografts (PDXs) with co-occurring HER3 and KRAS mutations and have generated patient derived organoids from these PDXs. Ongoing studies are determining if there is a synergistic relationship with KRAS inhibitors and HER family inhibitors including a HER3 antibody-drug conjugate. Our findings may present a new paradigm for targeted combination therapies in colorectal cancer with the eventual goal of increased overall patient survival. Citation Format: Mary K. Kilroy, Briley Park, Rosalin Mishra, Wasim Feroz, Cecilia Wischmeier, Joan T. Garrett. Molecular insights into the oncogenic influence between mutant HER3, mutant KRAS, and their synergistic interplay in colorectal cancer pathogenesis [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 7150.

Abstract 248: HSPA9/mortalin regulates erythroid maturation through a TP53-dependent mechanism in human CD34+ hematopoietic progenitor cells

Abstract Mortalin, encoded by the HSPA9 gene, is a highly conserved heat-shock chaperone belonging to the HSP70 family. It is predominantly presented in the mitochondria, and is critical in regulating a variety of cell physiological functions such as response to cell stress, control of cell proliferation, and inhibition/prevention of apoptosis. Myelodysplastic syndromes (MDS) are a group of hematopoietic stem cell malignancies characterized by ineffective hematopoiesis, increased apoptosis of bone marrow cells, and anemia. Up to 25% of MDS patients harbor an interstitial deletion on the long arm of chromosome 5, also known as del(5q), creating haploinsufficiency for multiple genes including HSPA9. Our prior study showed that knockdown of HSPA9 induces TP53-dependent apoptosis in human CD34+ hematopoietic progenitor cells, consistent with cytopenia observed in MDS patients. Since anemia is another featured symptom of MDS, we hypothesize that HSPA9 plays a role in regulating erythroid maturation. To test our hypothesis, we inhibited the expression of HSPA9 using various methods and measured the erythroid maturation in human CD34+ cells. We used siRNA targeting HSPA9 and found that HSPA9 siRNA significantly inhibited the cell growth, increased cell apoptosis, inhibited erythroid maturation (using CD71 as a surrogate marker), and increased p53 expression (p<0.01) compared to control siRNA in human CD34+ cells. Pharmacologic inhibition of HSPA9 by the chemical MKT-077, an inhibitor of HSP70 protein family members including mortalin, also increased p53 expression and inhibited erythroid maturation in human CD34+ cells. In addition, knockdown of HSPA9 by shRNA showed significant inhibition of erythroid maturation in human CD34+ cells compared to control shRNA. In order to test whether the regulation of erythroid maturation by HSPA9 is TP53-dependent or not, we constructed shRNAs targeting TP53 genes and simultaneously transduced lentivirus containing shRNAs targeting HSPA9 and TP53 respectively in human CD34+ cells using double antibiotics selection (puromycin for shRNA targeting HSPA9 and hygromycin for shRNA targeting TP53). We found that TP53 knockdown partially rescued the erythroid maturation defect caused by HSPA9 inhibition, suggesting that erythroid maturation inhibition by HSPA9 knockdown is partly mediated through a TP53 mechanism. Collectively, our results suggest that the increased apoptosis and reduced erythroid maturation observed in del(5a)-associated MDS is TP53-dependent. HSPA9/mortalin may be a potential target to treat anemia in del(5q) MDS patients, although simultaneous loss of multiple genes on del(5q) likely contributes to the complex phenotypes observed in MDS. Thus, our study not only uncovers some underlying mechanisms of del(5q) MDS, but also provides potential therapeutic indications through gene targeting in clinical MDS treatment. Citation Format: Tuoen Liu, Christopher Butler, Morgan Dunmire, Gabor Szalai, Anissa Johnson, Jaebok Choi, Matthew Walter. HSPA9/mortalin regulates erythroid maturation through a TP53-dependent mechanism in human CD34+ hematopoietic progenitor cells [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 248.

Abstract 5914: Non-muscle myosin IIA as a promising therapeutic target in breast cancer

Abstract We aimed to determine the role of non-muscle myosin IIA (NMIIA) in breast cancer using various cancer cell lines including estrogen receptor (ER)+, HER2+ and triple negative breast cancers (TNBC). Myosin heavy chain 9 (MYH9) gene encodes for the heavy chain of the hexameric protein NMIIA. We have recently identified that NMIIA serves as a binding partner for HER3 following the inhibition of the HER family member compared to the vehicle control treatment, as observed in HER3 immunoprecipitates. We checked the basal protein and mRNA levels of NMIIA in different breast cancer cell lines and found higher levels of NMIIA in both HER2+ and TNBC cell lines compared to ER+ cell lines. These data correlate with clinical data of primary breast cancer patients with high MYH9 being less likely in ER+ breast cancer patients and more likely in the PAM50 subtypes basal and HER2 enriched breast cancer patients. By employing a pool of four siRNA targeting MYH9, our data indicated a reduction in proliferation of HER2+ and TNBC cell lines when compared to the control siRNA. We have previously found that loss of MYH9 sensitizes to the HER family inhibitor neratinib treatment as assessed by cell proliferation, colony formation on matrigel, cell migration and invasion. We aimed to determine if pharmacological inhibition of the NMIIA pathway would sensitize to neratinib. RhoA-associated kinase (ROCK) serves as a master regulator of NMIIA activity as it directly phosphorylates the regulatory light chain (RLC) of NMIIA. Pharmacological inhibition of ROCK-NMIIA pathway using the ROCK inhibitor GSK269962A alone or in combination with neratinib reduced the cell proliferation in HER2+ cell lines BT474 and MDA-MB-453 as indicated by MTT and cell proliferation assay. It is well known that HER2-targeted therapies cause the upregulation of HER3. Given our identification of NMIIA as one of the interacting partners of HER3, our focus will be on investigating the NMIIA-HER3 signaling axis to elucidate its contribution to an adaptive response to HER2 inhibition and potential treatment resistance. Furthermore, we will explore strategies to target NMIIA in breast cancer. Citation Format: Wasim Feroz, Rosalin Mishra, Mary Kate Kilroy, Joan T. Garrett. Non-muscle myosin IIA as a promising therapeutic target in breast 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 5914.