shRNA Silencing Research Articles

In-vitro evidence indicating that IL-10 causes aging-related hypoalbuminemia via JAK1/STAT3 and CEBP-β

Albumin (ALB) has numerous vital physiological outcomes for healthy aging. A decrease in serum albumin, i.e., hypoalbuminemia, is one of the risk factors associated with aging, which affects physiological functioning. Hypoalbuminemia is the outcome of either decreased ALB synthesis or increased degradation. However, the potential mechanism controlling ALB's mRNA level expression in aged individuals is yet to be explored. We noted decreased serum ALB concentrations in aged individuals participating in our study, as compared to the young ones. We found that IL-10, a paradoxical inflammaging marker, reduced ALB concentration in HepG2 cells. Inhibiting the JAK/STAT3 signalling increased albumin mRNA suggesting its IL-10-driven regulation via JAK/STAT3 pathway. Albumin promotor analysis revealed the presence of a CEBP-β binding site. We showed that CEBP-β binds to the albumin promoter in an IL-10-dependent manner. Further, IL-10 increased the expressions of all CEBP-β isoforms, including the inhibitory isoform (LIP). The CEBP-β inhibition either by a functional inhibitor (i.e., quercetin) or shRNA silencing increased albumin mRNA in HepG2 cells. Our finding showed that IL-10 likely regulates albumin expression in a JAK/STAT3 and CEBP-β dependent manner in aging. A better understanding of the underlying condition can improve albumin protein levels and the well-being of the aged population.

Helicobacter pylori-Induced Decrease in Membrane Expression of Na,K-ATPase Leads to Gastric Injury.

Helicobacter pylori is a highly prevalent human gastric pathogen that causes gastritis, ulcer disease, and gastric cancer. It is not yet fully understood how H. pylori injures the gastric epithelium. The Na,K-ATPase, an essential transporter found in virtually all mammalian cells, has been shown to be important for maintaining the barrier function of lung and kidney epithelia. H. pylori decreases levels of Na,K-ATPase in the plasma membrane of gastric epithelial cells, and the aim of this study was to demonstrate that this reduction led to gastric injury by impairing the epithelial barrier. Similar to H. pylori infection, the inhibition of Na,K-ATPase with ouabain decreased transepithelial electrical resistance and increased paracellular permeability in cell monolayers of human gastric cultured cells, 2D human gastric organoids, and gastric epithelium isolated from gerbils. Similar effects were caused by a partial shRNA silencing of Na,K-ATPase in human gastric organoids. Both H. pylori infection and ouabain exposure disrupted organization of adherens junctions in human gastric epithelia as demonstrated by E-cadherin immunofluorescence. Functional and structural impairment of epithelial integrity with a decrease in Na,K-ATPase amount or activity provides evidence that the H. pylori-induced downregulation of Na,K-ATPase plays a role in the complex mechanism of gastric disease induced by the bacteria.

Non-Canonical STING-PERK Pathway Modulation of Cellular Senescence and Therapeutic Response in Sepsis-Associated Acute Kidney Injury.

Abstract-This study explored the role of the non-canonical STING-PERK signaling pathway in sepsis-associated acute kidney injury (SA-AKI). Gene expression data from the GEO database and serum STING protein levels in patients with SA-AKI were analyzed. An LPS-induced mouse model and an in vitro model using HK-2 cells were used to investigate the role of STING in SA-AKI. STING expression was suppressed using shRNA silencing technology and the STING inhibitor C176. Kidney function, inflammatory markers, apoptosis, and senescence were measured. The role of the STING-PERK pathway was investigated by silencing PERK in HK-2 cells and administering the PERK inhibitor GSK2606414. STING mRNA expression and serum STING protein levels were significantly higher in patients with SA-AKI. Suppressing STING expression improved kidney function, reduced inflammation, and inhibited apoptosis and senescence. Silencing PERK or administering GSK2606414 suppressed the inflammatory response, cell apoptosis, and senescence, suggesting that PERK is a downstream effector in the STING signaling pathway. The STING-PERK signaling pathway exacerbates cell senescence and apoptosis in SA-AKI. Inhibiting this pathway could provide potential therapeutic targets for SA-AKI treatment.

Modified Fangji Huangqi Decoction alleviates renal interstitial fibrosis by inhibiting TGF-β1/Smad/Snail signaling pathway during epithelial-mesenchymal transition

This study investigated the effects of modified Fangji Huangqi Decoction on the expression of proteins related to epithelial-mesenchymal transition(EMT) in a mouse model of unilateral ureteral obstruction( UUO) and in a rat renal tubular epithelial cell(NRK-52E) model of fibrosis induced by transforming growth factor β1(TGF-β1). It aims to decipher the molecular mechanism by which modified Fangji Huangqi Decoction alleviates renal interstitial fibrosis. C57/BL mice were subjected to UUO.After the surgery, the mice were treated with 0. 5-fold and 2-fold concentrations of modified Fangji Huangqi Decoction and fosinopril sodium(positive control) for 7 days. The interstitial collagen deposition in the kidney was assessed by Masson staining. Western blot and RT-qPCR were employed to determine the expression levels of TGF-β1, phosphorylated Smad2/3(p-Smad2/3), Smad2/3, Snail,epithelial cadherin(E-cadherin), alpha smooth muscle actin(α-SMA), and vimentin. The NRK-52E cell model induced by TGF-β1was treated with the serum samples collected from SD rats treated with different concentrations of modified Fangji Huangqi Decoction.The CCK-8 assay was employed to examine the effects of the serum samples on NRK-52E cell proliferation. The cell morphology in different groups was observed under a microscope. Furthermore, the modeled cells were treated with the serum containing 1-fold decoction. Western blot and RT-qPCR were then employed to measure the expression levels of p-Smad2/3, Smad2/3, Snail,E-cadherin, α-SMA, and vimentin in the cells. Under the same conditions, sh RNA was used to silence the Snail gene, and measurements were repeated before and after treatment with the serum containing 1-fold decoction. The results indicated that modified Fangji Huangqi Decoction alleviated the fibrotic injury in the mouse model of UUO and the fibrosis in the NRK-52E cell model. The treatment with the decoction down-regulated the protein and m RNA levels of EMT-related indicators including p-Smad2/3, α-SMA,Snail, and vimentin, while it up-regulated the expression of E-cadherin. After sh RNA silencing of the Snail gene, the protein and m RNA levels of E-cadherin, α-SMA, and vimentin showed no significant differences before and after treatment with the serum containing the decoction. The results suggest that modified Fangji Huangqi Decoction may alleviate renal interstitial fibrosis by inhibiting the TGF-β1/Smad/Snail signaling pathway and regulating the EMT process.

Identification of Prominin-2 as a new player of cardiomyocyte senescence in the aging heart.

The aging heart is characterized by a number of structural changes leading to ventricular stiffness, impaired resistance to stress and increased risk of developing heart failure (HF). Genetic or pharmacological removal of senescent cells has recently demonstrated the possibility to relieve some cardiac aging features such as hypertrophy and fibrosis. However, the contribution of the different cell types in cardiac aging remains fragmentary due to a lack of cell-specific markers. Cardiomyocytes undergo post-mitotic senescence in response to telomere damage, characterized by persistent DNA damage response and expression of the classical senescence markers p21 and p16, which are shared by many other cell types. In the present study, we used transcriptomic approaches to discover new markers specific for cardiomyocyte senescence. We identified Prominin2 (Prom2), encoding a transmembrane glycoprotein, as the most upregulated gene in cardiomyocytes of aged mice compared to young mice. We showed that Prom2 was upregulated by a p53-dependent pathway in stress-induced premature senescence. Prom2 expression correlated with cardiomyocyte hypertrophy in the hearts of aged mice and was increased in atrial samples of patients with HF with preserved ejection fraction. Consistently, Prom2 overexpression was sufficient to drive senescence, hypertrophy and resistance to cytotoxic stress while Prom2 shRNA silencing inhibited these features in doxorubicin-treated cardiac cells. In conclusion, we identified Prom2 as a new player of cardiac aging, linking cardiomyocyte hypertrophy to senescence. These results could provide a better understanding and targeting of cell-type specific senescence in age-associated cardiac diseases.

Set7 Methyltransferase and Phenotypic Switch in Diabetic Glomerular Endothelial Cells.

Hyperglycaemia influences the development of glomerular endothelial cell damage and nowhere is this more evident than in the progression of diabetic kidney disease (DKD). While the Set7 lysine methyltransferase is a known hyperglycaemic sensor, its role in endothelial cell function in the context of DKD remains poorly understood. Single-cell transcriptomics was used to investigate Set7 regulation in a mouse model of DKD, followed by validation of findings using pharmacological and shRNA inhibition of Set7. Set7 knockout (Set7KO) improved glomerular structure and albuminuria in a mouse model of diabetes. Analysis of single cell RNA-seq (scRNA-seq) data showed dynamic transcriptional changes in diabetic renal cells. Set7KO controls phenotype switching of GEN cell populations through transcriptional regulation of IGFBP5 (Insulin growth factor binding protein 5). Chromatin immunoprecipitation assays confirmed the expression of the IGFBP5 gene was associated with mono- and di-methylation of histone H3 lysine 4 (H3K4me1/2). The generalisability was investigated in human renal and circulating hyperglycaemic cells exposed to TGFβ1. We show that the highly selective Set7 inhibitor, PFI-2, attenuated indices associated with renal cell damage and mesenchymal transition; specifically (i) reactive oxygen species production, (ii) IGFBP5 gene regulation, and (iii) expression of mesenchymal markers. Furthermore, renal benefit observed in Set7KO diabetic mice closely correspond in human GEN cells with PFI-2 inhibition or Set7 shRNA silencing. Set7 regulates the phenotypic endothelial-mesenchymal transition (EDMT) switch and suggest that targeting the lysine methyltransferase could protect glomerular cell injury in DKD.

Abstract 463: The small nucleolar RNA SNORD46 and SNORD72 have tumor suppressor activity in diffuse large B cell lymphoma

Abstract Background. Following the identification of an 11q24.3 gain upregulating the ETS factors ETS1 and FLI1 in diffuse large B cell lymphoma (DLBCL) (Bonetti et al. Blood 2013), we observed the anti-lymphoma activity of blocking the protein-protein interaction of ETS factors with RNA helicases, using YK-4-279 and its clinical derivative TK-216 (Spriano, Chung et al. CCR 2019). DLBCL cells exposed to the two small molecule inhibitors presented a significant upregulation of small nucleolar RNAs (snoRNAs). Besides their primary functions in rRNA processing, snoRNAs are often deregulated in cancers, with microRNA-like actions and direct interaction with proteins. Here, we characterized SNORD46 and SNORD72, the two snoRNAs most upregulated cells after YK-4-279 and TK-216 and mapped to the 1p34.1 locus recurrently lost in DLBCL. Methods. Real-time PCR, immunoblotting, and shRNA silencing were conducted based on established protocols. RNA-Protein Interaction Prediction (RPISeq) was used to calculate the interaction probabilities of snoRNAs with proteins of interest. The prediction was made using both the Random Forest (RF) and the Support Vector Machine (SVM) classifiers, using a stringent threshold of >0.6. Results. The time-dependent changes of SNORD46 and 74 were validated with real-time PCR in the U2932 activated B cell-like (ABC) DLBCL cell line exposed to YK- 4-279 for 4 or 8 h. Upregulation of SNORD46 and 74 were significantly upregulated compared to their host genes upon YK-4-279 treatment, suggesting these snoRNAs have different functions from the genes in which they are encoded. Across 48 lymphoma cell lines, SNORD74 was more expressed in ABC DLBCL than in the remaining cell lines (P 0.03) or GCB DLBCL (P 0.05), while SNORD46 did not differ. Stable lentiviral-based overexpression of SNORD46 and 74, U2932 ABC DLBCL demonstrated that both SNORD46 and SNORD74 overexpression impaired growth while SNORD92, the control did not SNORD74 overexpression inhibited pAKT-Ser473, suggesting it could exert its anti-tumor effect by negatively impacting BCR signaling. Since constitutive BCR is the main driver for the pathogenesis in ABC DLBCL, we studied the impact of BCR signaling on SNORD46 and 74 expressions. IgM stimulation downregulated the snoRNAs in U2932 and TMD8 ABC DLBCL cell lines at 1 and 2.5 h poststimulation, with a more substantial effect for SNORD74. Furthermore, the snoRNAs were upregulated in four ABCs and four GCB DLBCLs cell lines exposed to the PI3K/mTOR inhibitor bimiralisib. Bioinformatic analysis indicated the possible binding of SNORD46 and especially of SNORD74 to BCR signaling molecules (SYK, LYN, BTK, PI3Kδ, IRAK4, IRAK1, CARD11), RNA helicases (RHA, DDX21, DDX5) and essential DLBCL proteins (BCL6, IRF4). Conclusions. SNORD46 and SNORD74 exert tumor suppressor activity in DLBCL cells, possibly as negative regulators of the BCR signaling. Citation Format: Elaine YL Chung, Filippo Spriano, Sara Napoli, Giulio Sartori, Luciano Cascione, Francesco Bertoni. The small nucleolar RNA SNORD46 and SNORD72 have tumor suppressor activity in diffuse large B cell lymphoma [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 463.

Abstract B086: Targeting ATR to overcome Carboplatin resistance in triple-negative breast cancer patient-derived models

Abstract Background: Triple negative breast cancer subtype is associated with poor prognosis and is mostly treated with chemotherapy, including the DNA crosslinking agent Carboplatin. Carboplatin treatment leads to DNA damage and a cell cycle inhibition allowing DNA damage repair. However, many patients are resistant or develop resistance to Carboplatin. The identification of novel treatments against chemoresistant TNBC is a major unmet clinical need. Method: TNBC patient-derived cell lines (PDCs) from patient-derived xenografts (PDXs) generated from chemotherapy resistant tumors were used for shRNA high throughput screens to identify genetic vulnerabilities that could resensitize these cells to Carboplatin. Validation of this target was performed genetically by shRNA silencing and pharmacologically with commercially available target inhibitors both in vitro and in vivo, using Alamar Blue viability assays and calculating synergy using the Chou Talalay method. DNA damage was assessed using yH2AX expression, and apoptosis using c-PARP and Annexin V, by confocal microscopy, flow cytometry and/or western blotting. Results: We identified ataxia telangiectasia and Rad3-related protein (ATR) as a target in one of the cell lines screened and validated it with an ATR shRNA. We tested the combination of the ATR inhibitor (ATRi), Elimusertib, with Carboplatin and found the combination to be synergistic (Average CI=0.30). DNA damage was markedly increased with combination treatment and a pan-nuclear yH2AX staining together with increased pHH3 expression were observed, suggestive of mitotic catastrophe. Cells treated with Carboplatin accumulated in S phase and a shift toward G2/M when Elimusertib was added. Apoptosis was significantly increased with combination treatment. PKMYT1 and WEE1 are two kinases regulating cell cycle entry by inhibiting CDK1, which controls entry into mitosis. Carboplatin treatment resulted in an increase in PKMYT1 expression. PKMYT1 inhibition with RP6306 re-sensitized the cells to Carboplatin more than WEE1 inhibition with Adavosertib, and this synergy was further increased with low doses of Elimusertib. Gene silencing of WEE1 and PKMYT1 both re-sensitized the cells to Carboplatin, but only WEE1 silencing alone significantly prevent proliferation, suggesting the requirement of PKMYT1 activity for resistance but not for cell proliferation without Carboplatin. In vivo validation using the PDXs from which the cell lines have been derived, demonstrated a significant delayed in tumor growth and prolonged survival when combining Carboplatin with ATRi compared to Carboplatin alone in two models. Conclusion: ATR inhibition resensitizes drug resistant TNBC cells to Carboplatin both in vitro and in vivo. The combination of Carboplatin with ATRi led to DNA damage and mitotic catastrophe. PKMYT1 plays a role in Carboplatin-resistant TNBC, collaborating with ATR in managing the cell cycle response to DNA damage, and PKMYT1 inhibition also re-sensitizes cells to Carboplatin, an effect increased with the triple combination of adding ATR inhibition. Citation Format: Juliet Guay, Catherine Chabot, Cédric Darini, Marguerite Buchanan, Adriana Aguilar-Mahecha, Tim Kong, Connie Yang, Mark Basik, Sidong Huang. Targeting ATR to overcome Carboplatin resistance in triple-negative breast cancer patient-derived models [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B086.

Targeting hexokinase 1 alleviates NLRP3-mediated inflammation in apical periodontitis: A laboratory investigation.

The aim of the study was to explore whether hexokinase 1 (HK1) is involved in the inhibition of inflammation mediated by nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) signalling pathway in the development of apical periodontitis (AP). Human AP tissues and normal control tissues were collected in the clinic. First, the levels of glucose, pyruvate, lactate and hexokinase activity were examined in human AP tissues. ECAR and OCR were further measured to detect the level of glycolysis in vitro model of inflammation, which established with lipopolysaccharide (LPS)-stimulated RAW264.7 cell line. Secondly, the expression of HK1, NLRP3, caspase-1 and interleukin (IL)-1β were measured by Western blot, immunohistochemistry or RT-qPCR. Finally, lentiviral short hairpin RNA (shRNA) silencing technique or the inhibitor 2-deoxy-d-glucose (2-DG) were used to further detect the relationship between HK1-mediated glycolysis and NLRP3-mediated inflammation in the development of AP in vitro. Initially, the level of glycolysis was significantly increased in human AP tissues. Subsequently, the expression of HK1, NLRP3, caspase-1 and IL-1β were upregulated significantly in human AP tissues. Furthermore, in the model of AP in vitro, a high level of glycolysis and the high expression of HK1, NLRP3, caspase-1 and IL-1β was observed. Finally, the expression of NLRP3, caspase-1 and IL-1β mediated by LPS stimulation was significantly reduced via HK1 knockdown or 2-DG treatment in vitro. Our data support that HK1-mediated glycolysis plays a crucial role in the development of AP via upregulating the NLRP3 signalling pathway. Moreover, targeting HK1 may contribute to prevent the progression of AP, which has a potential clinical translation.

Ras suppressor 1 long form (RSU1L) silencing promotes apoptosis in invasive breast cancer cells

Ras Suppressor-1 (RSU1) is a cell-extracellular matrix (ECM) adhesion protein implicated in breast cancer (BC) cell metastasis. Nevertheless, its role in apoptosis is yet unknown. In the present study, we used bioinformatics tools to evaluate the association of RSU1 expression and BC patient survival, the expression of basic pro- and anti-apoptotic genes in metastatic BC samples and their correlation with the expression of RSU1. Then, we specifically depleted RSU1 long form (RSU1L) using a short hairpin RNA (shRNA) silencing approach in two BC cell lines, the non-invasive MCF-7 and the highly invasive MDA-MB-231-LM2 cells and assessed gene expression of pro-and anti-apoptotic genes, as well as cell survival and apoptosis. Our results showed that high RSU1 expression was correlated with poor survival and significant changes were found in the expression of apoptosis-related genes (PUMA, TP53, BCL-2 and BCL-XL) in metastatic BC. Moreover, silencing of the long and most common isoform of RSU1 (RSU1L) resulted in the upregulation of PUMA and TP53 and concomitant downregulation of anti-apoptotic BCL-2 and BCL-XL, with the effect being more prominent in invasive MDA-MB-231-LM2 cells. Finally, RSU1L depletion leads to a dramatic increase in apoptosis of MDA-MB-231-LM2 cells, while no change was observed in the apoptotic rate of MCF-7 cells. This is the first study linking RSU1L with apoptosis and provides evidence for its differential role in cell lines of different invasive potential. This indicates that RSU1L represses apoptosis in aggressive BC cells helping them evade cell death and survive.

Abstract P2082: Igfbp-3 Activates Pro-survival Pathways To Mitigate Anthracycline-induced Cardiomyocyte Injury

Rationale: Anthracyclines such as doxorubicin are among the most effective chemotherapeutic agents; however, their use leads to frequent cardiovascular complications, including heart failure, due to the activation of multiple cardiomyocyte injury pathways. Insulin-like growth factor binding protein-3 (IGFBP3) is strongly upregulated in cardiomyocytes after administration of doxorubicin. However, its role in doxorubicin-induced cardiomyocyte apoptosis and survival remains controversial. Methods and Results: We demonstrate that IGFBP3 is strongly induced by doxorubicin in neonatal ventricular myocytes (NRVMs) 12 hours after doxorubicin treatment by RT-PCR (4.2 fold vs. control, n=3, P<0.05) and Western blot. Adenoviral overexpression of IGFBP3 in NRVMs leads to a significant reduction of phosphorylated H2A histone (γH2AX) after doxorubicin treatment, a hallmark of DNA double-strand breaks (DSBs), as well as topoisomerase IIβ, a key mediator of doxorubicin induced DNA DSBs. Conversely, silencing of IGFBP3 with siRNA leads to a significant increase of γH2AX expression in NRVMs. Adenoviral shRNA silencing of IGFBP3 in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) further demonstrates a 44% and 52% decrease in contraction magnitude and velocity in response to doxorubicin compared with scramble shRNA (scramble shRNA, n=5, shIGFBP3, n=3, P<0.05). Immunofluorescent imaging and cell fractionation assays conducted in NRVMs indicate that doxorubicin initiates IGFBP3 nuclear translocation, suggesting an active role in the cardiomyocyte response to doxorubicin-induced cell injury. Next generation sequencing of hiPSC-CMs treated with doxorubicin reveals that overexpression of IGFBP3 leads to upregulation of cardiomyocyte survival pathways, including TNF receptors without cytoplasmic death domain (TNFRSF10C and D), BCL2 family gene BCL2L1, the p53 target ACER2, the p53 co-factor FBXW7, the β-catenin mediator TBX3 and the ataxia telangiectasia mutated (ATM) activator ZNF423. Conclusion: Our findings indicate that IGFBP3 is strongly induced in cardiomyocytes by doxorubicin treatment. Overexpression of IGFBP3 attenuates doxorubicin induced DNA DSBs and promotes pro-survival signaling pathways.

FZD7 accelerates hepatic metastases in pancreatic cancer by strengthening EMT and stemness associated with TGF-β/SMAD3 signaling

BackgroundMetastasis of malignant tumors accelerates systemic failure and hastens the deaths of pancreatic cancer patients. During the metastatic process, the physical translocation of cancer cells from the primary lesion to distant organs and is crucial. CSCs properties, such as self-renewal and multiple-direction differentiation capacity are essential for colonization in the microenvironment of distant organs and metastatic lesion formation. It is widely believed that EMT can cause cancer cells to penetrate blood vessels by undergoing phenotypic and cytoskeletal changes, so that they can infiltrate surrounding tissue and disseminate from the primary tumor to the blood circulation, where they are termed circulating tumor cells (CTCs), while CTCs often exhibit stemness properties. Accumulating evidence demonstrates that some EMT-related transcription factors are essential for CSCs self-renewal, so cancer cells that have undergone EMT typically acquire increased stemness properties. Abnormal activation of the WNT signaling pathway can drive a series of gene transcripts to promote EMT in multiple types of cancer, and among different Frizzled receptors of WNT signaling pathway, FZD7 expression is associated with distant organ metastasis, advanced clinical stages, and poor clinical prognosis. Objective of this study is to demonstrate that high FZD7 expression in pancreatic cancer can accelerate hepatic metastases and elucidate the related molecular mechanisms.MethodsThe expression of Frrizled receptor 7 (FZD7) in pancreatic ductal adenocarcinoma (PDAC) and relating survival rate were analyzed by bioinformatics, histochemistry assay and follow-up study. In vitro, FZD7 expression was silenced by lentiviral vectors carrying short hair RNA (shRNA) or upregulated by overexpression plasmid. Then, Wound-healing and Transwell experiment was used to analyze the abilities of migration and invasion; the levels of epithelial-to-mesenchymal transition (EMT) relating phenotype proteins, stemness relating phenotype proteins, and signaling molecular proteins were measured by Western-blot; cell stemness was evaluated by sphere forming ability of cells in suspension culture and detecting the proportion of CD24+CD44+ cells with flow cytometry. TGF-β1 was used to induce EMT, and observe the effect of shRNA silencing FZD7 on which.ResultsHigh level of FZD7 expression in pancreatic cancer samples was associated with earlier hepatic metastasis. In vitro upregulation FZD7 can enable pancreatic cancer cells to obtain stronger migration and invasion ability and higher mesenchymal phenotype, and vice versa; the proportion of cancer stem cell (CSC) was also positively correlated with the level of FZD7; cells forming spheres in suspension culture showed stronger migration and invasion ability and higher level of mesenchymal phenotype than normal adherent cultured cells; the level of FZD7 was positively correlated with the level of activated β-catenin. Silencing FZD7 expression can attenuate EMT induced by TGF-β1 stimulating, and TGF-β1 stimulating can also upregulate stemness phenotype expression, such as ABCG2, CD24, and CD44 by mediating of FZD7.ConclusionsHigh FZD7 expression in pancreatic cancer can accelerates hepatic metastases by promoting EMT and strengthening cell stemness, and FZD7 can work through the canonical Wingless-type (WNT) signaling pathway and participate in TGF-β/SMAD3 signaling pathway also.

Abstract 3287: Baseline CD166 expression determines CRISPR-mediated ALCAM gene knockout effects on migratory phenotype in metastatic melanoma cells

Abstract Advanced stage melanoma is a mostly incurable, highly aggressive tumor whose incidence is rising. Metastatic dissemination of primary tumors involves the repeated crossing of tissues barriers, which requires dynamic modulation of tumor cell adhesion, presumably through mechanisms like those utilized by trafficking leukocytes. Activated leukocyte cell adhesion molecule (ALCAM/CD166) has been shown to play an important role in the metastatic process, including detachment from the primary tumor, adhesion to endothelium, and extravasation. ALCAM expression correlates with melanoma progression, and it has been identified as a marker of pluripotent stem cells. Furthermore, its expression in primary melanoma strongly correlates with tumor thickness and level of invasiveness. shRNA silencing of ALCAM in cells with high levels of ALCAM resulted in reduced motility and transmigration. In the current study, we tested the effect of CRISPR-mediated ALCAM knockout (KO) on migration and invasion of two human melanoma cell lines representing opposite phenotypic states of melanoma. MEL501 (proliferative type, SOX10/MITF-high and AP1/TEAD1-low) cells express low levels of ALCAM at baseline, while the Rosi cell line (invasive type, SOX10/MITF-low and AP1/TEAD1-high) expresses high baseline ALCAM levels. ALCAM KO promoted migration of MEL501 cells (p<0.000001) but inhibited migration of Rosi cells (p=0.005050) as compared to the parent cell lines. In addition, ALCAM KO promoted the invasion of MEL501 cells (p=0.019768) but had no impact on Rosi cell invasion. While ALCAM has been shown to regulate matrix metalloproteinase-2 (MMP-2) activation, zymograms revealed no difference in MMP-2 activity between MEL501 and Rosi ALCAM-KO cells and the parent cell lines. These data indicate that ALCAM may play a tumor-suppressive role in melanoma cells with low ALCAM expression and are consistent with a previous study which demonstrated that introduction of an amino-terminally truncated ALCAM in early stage melanoma cells promoted metastasis. Our data also provide in vitro evidence that gene therapy may reverse the migratory phenotype of melanoma cells with high ALCAM expression. Citation Format: Rafal Kaminski, Francesca P. Luongo, Konrad Dabrowski, Anna Bellizzi, Pietro Mancuso, M. Raza Zaidi, Johanna McMillan, Meha Patel, Tyrone Coleman, Oneida A. Arosarena. Baseline CD166 expression determines CRISPR-mediated ALCAM gene knockout effects on migratory phenotype in metastatic melanoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3287.

A Functional Variant in the Aquaporin-3 Promoter Modulates Its Expression and Correlates With Resistance to Porcine Epidemic Virus Infection in Porcine Intestinal Epithelial Cells.

Porcine epidemic diarrhea virus (PEDV) causes a highly contagious intestinal disease in neonatal pigs. Aquaporin-3 (AQP3) plays important roles in maintenance of intestinal barrier function and regulation of immune responses. However, the roles of AQP3 in mediating PEDV infection to host cells and the regulatory mechanisms of AQP3 expression remain poorly understood. Here, we identified one 16 bp (GGGCGGGGTTGCGGGC) insertion mutation in the AQP3 gene promoter in Large White pigs, with the frequencies of 49.3% of heterozygotes and 31.3% of mutant homozygotes. Functional analysis by luciferase activity assay indicated that the insertion mutation results in significant enhancement in AQP3 transcriptional activity (P < 0.01). Mechanistic analysis showed that the inserted sequence adds binding sites for transcription factor CEBPA, which promotes the expression of AQP3. Downregulation of AQP3 by shRNA silencing in porcine intestinal epithelial cells revealed obvious increases in genome copies and viral titers of PEDV. Expression of proinflammatory cytokines (IL-6, IL-8, and IL-18) and interferons (IFN-α and IFN-β) were significantly reduced (P < 0.01) in AQP3 knockdown cells upon PEDV infection. Furthermore, decreased level of ZO-1 protein was also detected in AQP3 knockdown cells in response to PEDV infection. Our findings suggested a previously unknown mechanism linking the effects of promoter genetic variants on the expression of AQP3, revealed the roles of AQP3 in response to PEDV pathogenesis, and indicated the potential associations of the 16 bp insertion mutation with resistance to PEDV infection in porcine intestinal epithelial cells.

Non-enzymatic function of WRN RECQL helicase regulates removal of topoisomerase-I-DNA covalent complexes and triggers NF-κB signaling in cancer.

Mutation in Werner (WRN) RECQL helicase is associated with premature aging syndrome (Werner syndrome, WS) and predisposition to multiple cancers. In patients with solid cancers, deficiency of the WRN RECQL helicase is paradoxically associated with enhanced overall survival in response to treatment with TOP1 inhibitors, which stabilize pathological TOP1‐DNA‐covalent‐complexes (TOP1cc) on the genome. However, the underlying mechanism of WRN in development of chemoresistance to TOP1 inhibitors is not yet explored. Our whole‐genome transcriptomic analysis for ~25,000 genes showed robust activation of NF‐κB‐dependent prosurvival genes in response to TOP1cc. CRISPR‐Cas9 knockout, shRNA silencing, and under‐expression of WRN confer high‐sensitivity of multiple cancers to TOP1 inhibitor. We demonstrated that WRN orchestrates TOP1cc repair through proteasome‐dependent and proteasome‐independent process, unleashing robust ssDNA generation. This in turn ensues signal transduction for CHK1 mediated NF‐κB‐activation through IκBα‐degradation and nuclear localization of p65 protein. Intriguingly, our site‐directed mutagenesis and rescue experiments revealed that neither RECQL‐helicase nor DNA‐exonuclease enzyme activity of WRN (WRNE84A, WRNK577M, and WRNE84A‐K577M) were required for TOP1cc removal, ssDNA generation and signaling for NF‐κB activation. In correlation with patient data and above results, the TOP1 inhibitor‐based targeted therapy showed that WRN‐deficient melanoma tumors were highly sensitive to TOP1 inhibition in preclinical in vivo mouse model. Collectively, our findings identify hitherto unknown non‐enzymatic role of WRN RECQL helicase in pathological mechanisms underlying TOP1cc processing and subsequent NF‐κB‐activation, offering a potential targeted therapy for WRN‐deficient cancer patients.

Dendrobine modulates autophagy to alleviate ox-LDL-induced oxidative stress and senescence in HUVECs.

Dendrobine has potential advantages in suppressing atherosclerosis (AS). FK506-binding protein 1A (FKBP1A) is implicated in the regulation of autophagy, inflammation, and apoptosis. To reveal the mechanism by which dendrobine inhibits AS by modulating autophagy, oxidative stress, apoptosis, and senescence. An in vitro AS cell model was induced by culturing human umbilical vein endothelial cells (HUVECs) with oxidized low-density lipoprotein (ox-LDL). The cells were treated with dendrobine alone or in combination with short hairpin RNA (shRNA) targeting FKBP1A or together with 3-methyladenine (3MA), an autophagy inhibitor. Inflammatory cytokines levels tumor necrosis factor-α, interleukin-6 (IL-6), and IL-1β were analyzed and oxidative stress levels were detected by the analysis of reactive oxygen species, malondialdehyde, and superoxide dismutase levels, followed by the analysis of apoptosis levels through terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Cell senescence was evaluated by senescence-associated β-galactosidase and light chain 3 (LC3) levels were detected by immunofluorescence (IF) staining. The targeting relationship of dendrobine and FKBP1A was predicted by SwissTarget, PyMol, Autodock, and Open Babel software. Dendrobine reduced the levels of proinflammation factors, oxidative stress levels, apoptosis levels, and senescence phenotype in ox-LDL-induced HUVECs. Besides, cell viability has an opposite change. Furthermore, there was an increase in LC3 IF tensity, and LC3-II/I and Beclin1 expressions, and a decrease in p62 expression. However, these effects of dendrobine could be markedly destroyed by shRNA silencing FKBP1A and 3MA. Dendrobine can suppress inflammatory responses, oxidative stress, apoptosis, and senescence via FKBP1A-involved autophagy ox-LDL-treated HUVECs.

Role of lipocalin-2 in surgery-induced cognitive decline in mice: a signal from neuron to microglia

BackgroundPerioperative neurocognitive disorders (PNDs) are common complications observed among surgical patients. Accumulating evidence suggests that neuroinflammation is one of the major contributors to the development of PNDs, but the underlying mechanisms remain unclear.MethodsqPCR and ELISA analysis were used for detecting LCN2 and cytokine levels. cx3cr1CreER/−:: R26iDTR/− crossed mouse line was used for microglia depletion; intracranial injection of recombinant LCN2 (rLCN2) and adeno-associated viruses (AAV)-mediated shRNA silencing approaches were used for gain and loss of function, respectively. Combing with in vitro microglia cell culture, we have studied the role of LCN2 in surgery-induced cognitive decline in mice.ResultsWe revealed that Lcn2 mRNA and protein levels were greatly increased in mouse hippocampal neurons after surgery. This surgery-induced elevation of LCN2 was independent of the presence of microglia. Gain of function by intracranial injection of rLCN2 protein into hippocampus disrupted fear memory in naive mice without surgery. Conversely, silencing LCN2 in hippocampus by AAV-shRNA protected mice from surgery-induced microglia morphological changes, neuroinflammation and cognitive decline. In vitro, application of rLCN2 protein induced the expression of several pro-inflammatory cytokines in both BV-2 and primary microglia culture.ConclusionsThese data suggest LCN2 acts as a signal from neuron to induce proinflammatory microglia, which contributes to surgery-induced neuroinflammation and cognitive decline in mice.

Selected Articles from This Issue

Despite previous assumptions that constitutively high Wnt signaling promotes colorectal cancer in each stage of disease, recent studies have demonstrated that reduced Wnt signaling is associated with colorectal cancer invasiveness and poor prognoses. However, little work has been done to elucidate how diminished Wnt signaling underlies aggressive colorectal cancer phenotypes. Chen and colleagues used genetic manipulation strategies and orthotopic mouse models to show that abrogating Wnt signaling increases colorectal cancer invasiveness and decreases immune responsiveness in vivo. Disrupting Wnt signaling by targeting Wnt coreceptor LDL receptor-related protein 6 (LRP6) with CRISPR/Cas9 or transducing a dominant negative version of Wnt transcriptional effector lymphoid enhancer binding factor 1 (LEF1) increases tumor submucosal invasion and dissemination in mice. Using RNA-Seq, the authors revealed that reducing Wnt signaling elevates expression of markers associated with stemness and a mesenchymal phenotype, while repressing expression of immune-stimulatory molecules and collagens. The authors used TCGA data to demonstrate that the low Wnt signaling expression profile corresponds with poor survival in colorectal cancer patients, underscoring the potential clinical relevance of dampened Wnt signaling in colorectal cancer progression.Cholangiocarcinoma (CCA) is an aggressive biliary tract cancer for which effective therapeutics are lacking. Prostaglandin E2 (PGE2)-mediated inflammation is a critical component of CCA carcinogenesis and progression. 15-hydroxyprostaglandin dehydrogenase (15-PGDH) chemically modifies and inactivates PGE2, but its expression is often diminished in CCA. In their work, Zhang and colleagues leveraged public data to show that expression of histone methyltransferase G9a negatively correlates with 15-PGDH expression. The authors validated the G9a-15-PGDH relationship in a mouse model of CCA in which the Notch intracellular domain and constitutively active Akt are expressed via hydrodynamic injection of sleeping beauty transposase-based plasmids. shRNA-mediated G9a silencing increases 15-PGDH expression in CCA cell lines, limiting cell proliferation in vitro and tumor growth in vivo. ChIP assays demonstrated that G9a is recruited to the 15-PGDH promoter by the Myc/Max/E-box complex, which prevents signal transducer and activator of transcription 4 (STAT4) from binding the promoter and inducing 15-PGDH expression. The work presented elucidates a previously unknown mechanism underlying CCA development and progression and reveals a novel potential target for CCA therapeutic strategies.Neurofibromatosis type 2 is characterized by growth of benign nervous system tumors, such as schwannomas, which can lead to deafness, brain stem compression, and death. Neurofibromatosis type 2 is caused by mutations in tumor suppressor gene NF2. Previously, Cho and colleagues demonstrated that NF2 loss promotes elevated TβR1 signaling, resulting in phosphorylation and degradation of tumor suppressor Raf kinase inhibitor protein (RKIP). While TGF-β inhibitors halt schwannoma growth, they are not ideal therapeutics given schwannomas occur around adolescence and TGF-β is required for development. Here, Cho and colleagues developed a novel TβR1 inhibitor, Nf18001, that abrogates TβR1-mediated RKIP degradation while maintaining canonical TGF-β signaling. The authors used human and mouse schwannoma cell lines to demonstrate that Nf18001 disrupts TβR1-RKIP interactions to sustain RKIP expression and lower NF2-mutant cell viability while not influencing normal fibroblast survival. Nf18001 arrests cell cycle progression in schwannoma cells, and augments Schwann cell differentiation marker expression while diminishing expression of markers associated with cell stemness. Nf18001 also displayed efficacy in a schwannoma allograft mouse model, where treatment slowed tumor growth.The pro-tumorigenic role of signal transducer and activator of transcription 3 (STAT3) in multiple myeloma has been established, but therapeutically targeting STAT3 has proven challenging. Similarly, given its canonical role in DNA damage repair, checkpoint kinase 1 (Chk1) inhibition has been tested in anti-cancer therapeutic regimens, but with ambiguous results. In their study, Zhou and colleagues employed a gene expression array to demonstrate that Chk1 inhibition diminishes expression of oncogenic STAT3 target genes in multiple myeloma cells, suggesting Chk1 inhibition may also effectively inhibit STAT3 activity. Subsequent work showed that Chk1 directly binds to STAT3 and phosphorylates it at tyrosine 705, enabling STAT3 dimerization and DNA binding. Chk1 inhibition — pharmacologically and via shRNA silencing — diminishes STAT3 tyrosine 705 phosphorylation and inhibits STAT3 DNA binding, reducing expression of STAT3 transcriptional targets. Chk1 inhibition abrogates STAT3 tyrosine 705 phosphorylation in IL-6–dependent, -independent, and bortezomib-resistant cells, as well as in patient primary myeloma mononuclear cells and multiple myeloma cells implanted into mice, suggesting Chk1 inhibition may provide therapeutic efficacy against multiple myeloma through a STAT3-related mechanism.

Defining the role of PLD3 in Alzheimer disease pathology.

Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β (Aβ) in the brain. We recently identified coding variants in the phospholipase D3 (PLD3) gene that double the risk for late onset AD. We examined the impact of PLD3 risk variants on PLD3 and Aβ metabolism using CRISPR/Cas9 in induced pluripotent stem cells (iPSC). We then modeled the PLD3 expression patterns observed in AD brains in immortalized cell and AD mouse models. Lysosomal function was assessed in human brain tissue. PLD3 A442A disrupts a splicing enhancer binding site and reduces PLD3 splicing in human brains. Differentiation of PLD3 A442A and isogenic control iPSCs into cortical neurons produced cells that were morphologically similar. At the molecular level, PLD3 A442A neurons displayed a similar defect in PLD3 splicing as was observed in human brains and a significant increase in Aβ42/Aβ40 compared with isogenic control lines. Thus, PLD3 A442A is sufficient to alter PLD3 splicing and Aβ metabolism. PLD3 expression was significantly lower in AD brains compared with controls, and PLD3 expression was highly correlated with expression of lysosomal genes. Thus, we sought to determine whether PLD3 contributes to Aβ accumulation in AD via disrupted Aβ metabolism. We found that overexpression of PLD3 in immortalized cells decreased Aβ levels while shRNA silencing of PLD3 increased Aβ levels. In an AD mouse model, overexpression of PLD3 in hippocampal neurons produced decreased interstitial fluid (ISF) Aβ levels and accelerated Aβ turnover. Conversely, knocking out PLD3 increased ISF Aβ, reduced Aβ turnover, and increased APP protein levels. Thus, reduced turnover of ISF Aβ along with increase APP substrate may lead to Aβ accumulation. To begin to determine whether PLD3 influences Aβ turnover via the lysosome, we isolated lysosomal fractions from human AD and control brains. PLD3 was enriched in lysosomal subfractions and PLD3 distribution in these subfractions was altered in AD. Furthermore, PLD3 stability in the lysosomal fractions was disrupted in AD brains. Together, our findings demonstrate that PLD3 promotes Aβ clearance through pathways involving lysosomal degradation.

Defining the role of PLD3 in Alzheimer’s disease pathology

AbstractBackgroundAlzheimer’s disease (AD) is characterized by the accumulation of amyloid‐β (Aβ) in the brain. We recently identified coding variants in the phospholipase D3 (PLD3) gene that double the risk for late onset AD.MethodWe examined the impact of PLD3 risk variants on PLD3 and Aβ metabolism using CRISPR/Cas9 in induced pluripotent stem cells (iPSC). We then modeled the PLD3 expression patterns observed in AD brains in immortalized cell and AD mouse models. Lysosomal function was assessed in human brain tissue.ResultPLD3 A442A disrupts a splicing enhancer binding site and reduces PLD3 splicing in human brains. Differentiation of PLD3 A442A and isogenic control iPSCs into cortical neurons produced cells that were morphologically similar. At the molecular level, PLD3 A442A neurons displayed a similar defect in PLD3 splicing as was observed in human brains and a significant increase in Aβ42/Aβ40 compared with isogenic control lines. Thus, PLD3 A442A is sufficient to alter PLD3 splicing and Aβ metabolism. PLD3 expression was significantly lower in AD brains compared with controls, and PLD3 expression was highly correlated with expression of lysosomal genes. Thus, we sought to determine whether PLD3 contributes to Aβ accumulation in AD via disrupted Aβ metabolism. We found that overexpression of PLD3 in immortalized cells decreased Aβ levels while shRNA silencing of Pld3 increased Aβ levels. In an AD mouse model, overexpression of PLD3 in hippocampal neurons produced decreased interstitial fluid (ISF) Aβ levels and accelerated Aβ turnover. Conversely, knocking out Pld3 increased ISF Aβ, reduced Aβ turnover, and increased APP protein levels. Knocking out Pld3 overtime lead to altered amyloid morphology. To begin to determine whether PLD3 influences Aβ turnover via the lysosome, we isolated lysosomal fractions from human AD and control brains. PLD3 was enriched in lysosomal subfractions and PLD3 distribution in these subfractions was altered in AD. Furthermore, PLD3 stability in the lysosomal fractions was disrupted in AD brains.ConclusionTogether, our findings demonstrate that PLD3 promotes Aβ clearance through pathways involving lysosomal degradation.