Atherosclerosis (AS) is characterized by a gradual plaque buildup within the arteries, resulting in hardened and narrowed arteries. Thus, it leads to blood flow limitation and increased risk of critical diseases. Hyperlipidemia is correlated with inflammation, as seen with increased expression of different inflammatory markers including tumor-necrosis factor-alpha (TNF-α), C-reactive protein (CRP), chemokines and interleukins. This current study explores the relationship between novel anti-hyperlipidemic compounds and the expression of specific inflammatory markers in acute hyperlipidemic rats induced by Triton WR-1339.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor prognosis and resistance to conventional therapies, necessitating novel treatments. The high proliferative rate and protein synthesis in PDAC induce endoplasmic reticulum (ER) stress, with Glucose-Regulated Protein 78 (GRP78), a key regulator of ER stress and the Unfolded Protein Response (UPR), playing a pivotal role in PDAC progression. Despite its relevance, GRP78-targeted therapies remain unexplored in PDAC. BOLD-100, a novel GRP78 inhibitor, presents a potential therapeutic approach by disrupting GRP78 transcription, though its effects on PDAC have yet to be fully elucidated. Here, we found that BOLD-100 induces PDAC cell death through the UPR pathway activation, leading to CHOP-dependent apoptosis. BOLD-100 generates reactive oxygen species (ROS), inducing R-loop formation that triggers a DNA damage response via the ATR/Chk1 axis. BOLD-100 synergizes with AZD6738, an ATR inhibitor, to enhance anti-tumor efficacy compared to either agent alone in both in vitro and in vivo models. These findings suggest that BOLD-100, especially in combination with an ATR inhibitor, represents a promising therapeutic option for patients with PDAC.

Prostate cancer risk is influenced by various factors, including exposure to heavy metals like cadmium (Cd). The study reveals that the autophagy-regulating gene PLAC8 (placenta-specific 8) is significantly involved in Cd-induced prostate carcinogenesis, and NF-κB acts as the upstream transcriptional activator of PLAC8, which then selectively up-regulates BCL-xL, providing a survival advantage to Cd-transformed cells. NF-κB activation stabilizes PLAC8 in the cytosol, disrupting autophagy by allowing PLAC8 to colocalize with LC3B instead of LAMP1. Silencing NF-κB down-regulates PLAC8 and its survival function while inhibiting NF-κB or PLAC8, which restores autophagy and decreases tumor growth in xenograft models. In addition, targeting BCL-xL confirmed this signaling pathway. The findings suggest that sustained NF-κB activation regulates PLAC8 and highlights the NF-κB-PLAC8-BCL-xL axis as a potential target for early detection and therapies in metal-induced prostate cancer.

Cadmium (Cd²⁺) contamination severely threatens aquatic organisms, leading to oxidative stress, inflammation, and hepatotoxicity. Portulaca oleracea is known for its antioxidant and anti-inflammatory activities; yet, its defensive role against Cd²⁺-induced hepatotoxicity in Nile tilapia (Oreochromis niloticus) is still unclear. The current study evaluated the possible hepatoprotective effects of purslane leaf powder (PR) against Cd²⁺-induced liver damage and its mechanisms. A hepatotoxicity model was established by exposing tilapia to Cd²⁺ (50 µg/L) for 60 days, with and without PR supplementation (10 g PR/kg diet). Histopathological analysis, biochemical assays, and real-time quantitative PCR were done to assess liver tissue damage, oxidative stress markers, lipid profile, and inflammatory gene expression. Results showed that Cd²⁺ exposure induced severe hepatic alterations, including glycogen depletion, steatosis, necrosis, and inflammatory infiltration, along with increased liver indices and obvious dyslipidemia. PR supplementation significantly alleviated these changes by reducing oxidative stress, enhancing antioxidant enzyme activity, upregulating antioxidant genes (sod-1, sod-2, cat, gpx, and cyp1a), and downregulating inflammatory markers (mapk1, nf-κb, il1β, il6, il8, and tnf-α). Additionally, PR improved lipid profile and liver morphology, and reduced hepatocyte damage compared to the Cd²+-exposed group. In conclusion, PRP mitigates Cd²⁺-induced hepatotoxicity in Nile tilapia by enhancing antioxidant defenses and reducing inflammation, suggesting its potential as a dietary supplement to counteract heavy metal toxicity in aquaculture.

Cadmium (Cd) is a heavy metal widely distributed in the environment that poses a significant threat to living organisms because of its strong mobility and toxicity. In this study, a novel gene named Osß-glu from the glycosyltransferase (GT) family was investigated for its role in the Cd stress response in rice. Various experiments were conducted using the japonica cultivar Nipponbare (Nip) and its mutants (Osß-glu-1 and Osß-glu-2). The results showed that Osß-glu was specifically induced by Cd stress rather than by other mineral deficiencies. The Osß-glu mutants exhibited higher sensitivity to Cd stress, with more significant inhibition of root elongation, reduced biomass, and increased Cd accumulation in the roots, shoots, and xylem sap than Nip. Nitro-Blue Tetrazolium (NBT) staining indicated a larger acumulation of superoxide anion in the mutant roots under Cd stress, 3,3'-Diaminobenzidine (DAB) staining showed more pronounced H2O2 accumulation, and Evans Blue staining revealed more dead cells, demonstrating more severe reactive oxygen species (ROS) accumulation and cell damage in mutant roots. Moreover, the mutants had higher hemicellulose content and elevated Cd-binding capacity in the root cell wall, as well as abnormal expression of genes related to Cd absorption and translocation. Overall, multiple lines of evidence suggest that Osß-glu plays a crucial regulatory role in the response of rice to Cd stress, acting as an inhibitor of Cd accumulation. This contributes to a better understanding of the precise control network for Cd tolerance in rice, providing a basis for breeding rice varieties with lower Cd uptake.

Triple‑negative breast cancer (TNBC) is a lethal subtype of breast cancer with a poor prognosis and limited existing treatment options. The immune checkpoint inhibitor, anti‑programmed death ligand 1 (PD‑L1), has recently emerged as a promising alternative in treating TNBC. PD‑L1 is critical in tumor immune evasion and is therefore a key target for cancer immunotherapy. Although anti‑PD‑L1 therapy is effective in breast cancer based on clinical trials, the relationship between PD‑L1 expression levels and treatment response remains unclear. To investigate this, a 4T1 breast cancer cell line that stably overexpressed PD‑L1 was established and was used to create a tumor model in mice. Mice were treated with anti‑PD‑L1 antibodies, and tumor growth was compared between the control and treated groups. PD‑L1 overexpressing tumors did not exhibit an antitumor response to anti‑PD‑L1 therapy compared with the control tumors. Additionally, immune cell infiltration and activation were significantly altered, as shown by immunohistochemical staining and bulk RNA sequencing. In PD‑L1‑overexpressing tumors that did not respond to treatment, immune cell markers and antitumor immune pathways were downregulated. These results demonstrated that excessive PD‑L1 expression creates an immunosuppressive tumor microenvironment, which impairs the efficacy of anti‑PD‑L1 therapy. The present study suggests that excessive PD‑L1 expression reduces the effectiveness of antitumor immunotherapy, and that PD‑L 1 expression levels are essential in predicting the response to antitumor immunotherapy.

Andrographolide, fucoidan, or a combination of both compounds were evaluated to determine their effects on the antiviral response in the Atlantic salmon macrophage-like cell line (SHK-1) infected with infectious pancreatic necrosis virus (IPNV). We assessed the transcript expression levels of key molecules involved in the interferon (IFN)-dependent antiviral response, as well as the viral load in cells treated with these compounds. In non-infected cells, incubation with either fucoidan, andrographolide, or a mixture of both resulted in an increase in the transcript expression of IFNα1 and various interferon-stimulated genes (ISGs). In IPNV-infected cells, treatment with either fucoidan or andrographolide separately did not significantly enhance the antiviral response compared to that of infected cells that had not previously been treated with these compounds. In contrast, the combination of andrographolide and fucoidan led to a marked increase in the transcript expression of viperin and a significant reduction in viral load. Overall, combining andrographolide and fucoidan resulted in a greater reduction in IPNV viral load in infected cells than that noted when the compounds were administered individually. Our findings suggest that pre-incubation with this mixture promotes the establishment of a protective antiviral state against IPNV, likely mediated by an IFN-dependent response.

Breast cancer is a heterogeneous disease, and treatment resistance remains a critical challenge. Claudin-8 (CLDN8), a tight junction protein, has emerged as a potential indicator of therapeutic response and prognosis in breast cancer patients. In this study, we evaluated CLDN8 as a predictive biomarker and a potential therapeutic target. We analyzed CLDN8 gene expression in breast cancer patient cohorts to assess its association with clinical outcomes and response to therapy. We also established breast cancer cell models with altered CLDN8 expression to examine its effects on cell behavior and drug sensitivity. High CLDN8 expression was significantly associated with improved disease-free survival, particularly in estrogen receptor-negative patients (p = 0.007), suggesting a favorable prognostic role. Notably, tumors with elevated CLDN8 showed better outcomes in patients treated with surgery alone or endocrine therapy, whereas in those receiving chemotherapy (including neoadjuvant) or anti-HER2 therapy, high CLDN8 levels were paradoxically linked to poorer survival and therapy resistance. In vitro, CLDN8 knockdown reduced sensitivity to endocrine treatments, HER2-targeted agents, and chemotherapeutic drugs, mirroring clinical patterns. In conclusion, our findings identify CLDN8 as an important prognostic factor in breast cancer and as a novel predictor of treatment response. These results underscore the potential utility of CLDN8 status in guiding personalized therapy and highlight CLDN8 as a candidate target for overcoming treatment resistance in breast cancer.

The retinal pigment epithelium (RPE) plays a crucial role in maintaining retinal homeostasis, and dysregulation of the transforming growth factor-beta (TGF-β) signaling pathways contributes to retinal fibrosis and inflammatory diseases, including proliferative vitreoretinopathy (PVR). Tacrolimus (FK506), an immunosuppressant, has shown potential antifibrotic properties, but its effects on TGF-β-related genes and microRNAs (miRNAs) in RPE cells remain unclear. Human RPE (H-RPE) cells were treated with lipopolysaccharide (LPS) to induce inflammation and subsequently exposed to tacrolimus. Gene and miRNA expression profiling related to TGF-β signaling pathways were conducted using microarrays, followed by Quantitative Reverse-Transcription Polymerase Chain Reaction (RT-qPCR) validation. Protein levels were assessed via enzyme-linked immunosorbent assay (ELISA), and interactions were analyzed using STRING database network analysis. Tacrolimus modulated key components of the TGF-β pathway, upregulating TGF-β2, TGF-β3, SMAD2, and SMAD4 while downregulating TGF-βR1 and SMAD7. JAK/STAT and MAPK pathways were also affected, indicating broad regulatory effects. miRNA profiling identified hsa-miR-200a-3p, hsa-miR-589-3p, hsa-miR-21, and hsa-miR-27a-5p as key regulators. STRING analysis confirmed strong functional interactions within the TGF-β network. In conclusion, tacrolimus modulates both canonical (upregulation of SMAD2/4 and downregulation of SMAD7) and non-canonical (JAK/STAT and MAPK) TGF-β signaling pathways in LPS-stimulated RPE cells. These changes collectively suggest a dual anti-inflammatory and anti-fibrotic effect. The increased TGF-β2 and decreased SMAD7 levels, alongside altered miRNA expression (e.g., downregulation of miR-200a-3p), indicate that tacrolimus may inhibit key profibrotic mechanisms underlying PVR. These findings support the potential therapeutic repurposing of tacrolimus in PVR and warrant further in vivo validation.

Arsenic, a potent metalloid contaminant of drinking water, is known for its ability to act as an initiator and modulator of disease in a variety of human tissues. Upon ingestion, arsenic is bio-transformed in the liver into a variety of metabolites, including arsenite. Arsenite permeates the blood-brain barrier (BBB), inducing oxidative stress that can be detrimental to brain neurons. As the primary glial cell at the BBB interface, astrocytes play a pivotal role in detoxifying xenobiotics such as arsenite via the production of the tripeptide antioxidant γ-glutamylcysteine, or glutathione (GSH). In this study, we assessed the mRNA levels of key components of the GSH synthetic pathway in astrocytes exposed to arsenite compared to vehicle controls. These components included xCT [substrate-specific light chain of the substrate importing transporter, system xc- (Sxc-)], glutamate-cysteine ligase [both catalytic (GCLC) and modifying (GCLM) subunits], and glutathione synthetase (GS). Additionally, we analyzed protein levels of some components by Western blotting and evaluated functional activity of Sxc- using a fluorescence-based cystine uptake assay. Finally, we utilized a luminescence-based glutathione assay to determine the intracellular and extracellular GSH content in arsenite-treated cells. Arsenite significantly increased xCT, GCLC, GCLM, and GS mRNA levels, an effect blocked by the transcriptional inhibitor actinomycin D (ActD). A corresponding increase in Sxc- activity was also observed in the arsenite treatment groups, along with significant increases in GCLC and GCLM protein expression. However, no increase in GS protein expression was detected. Finally, arsenite treatment significantly increased extracellular GSH levels, an effect which was also prevented by the inclusion of ActD. Overall, our study provides evidence that arsenite transcriptionally regulates several cellular processes necessary for GSH synthesis in primary cortical astrocyte cultures, thereby contributing to a better understanding of how this environmental toxicant influences antioxidant defenses in the brain. However, these results should be interpreted with caution regarding their applicability to vivo systems.

The NOS1AP gene encodes the nitric oxide synthase 1 adaptor protein (NOS1AP), which binds to neuronal nitric oxide synthase (nNOS) and regulates nitric oxide (NO) production by dissociating nNOS from NMDA receptors (NMDARs). Notably, NOS1AP expression is upregulated upon NMDAR activation; however, there is no available data regarding its production under the receptor inhibition. The NOS1AP gene is also 1 among more than 1000 genes that are presumed to be associated with the development of schizophrenia. Various animal models of this disorder have been developed, some of which are based on the use of NMDAR antagonists such as dizocilpine (MK-801). In this study, we investigated the expression and production of NOS1AP in rats injected with a low dose of dizocilpine (0.1 mg/kg), as well as in SH-SY5Y and HEK293T cell lines treated with varying concentrations of the same compound (10-200 µM). According to our results, neither the expression of the NOS1AP gene nor the production of NOS1AP protein was affected by dizocilpine treatment.

Biochanin A, a naturally occurring isoflavone derived from legumes, possesses anti-inflammatory, estrogenic, and anticancer activities. In this study, we investigated the cytotoxic effects and underlying molecular mechanisms of Biochanin A in acute myeloid leukemia (AML) cell lines, U937 and THP-1, using in vitro cytotoxicity assays, RNA sequencing, and bioinformatic analyses. Biochanin A induced dose-dependent apoptosis, as evidenced by caspase-7 activation and PARP1 cleavage. Over-representation analysis (ORA) revealed that differentially expressed genes (DEGs) were significantly enriched in pathways related to inflammatory responses, DNA replication, and cell cycle regulation. Gene set enrichment analysis (GSEA) further confirmed the upregulation of apoptosis- and inflammation-related pathways and the downregulation of MYC targets, cholesterol biosynthesis, and G2/M checkpoint gene sets. RT-qPCR analysis demonstrated that Biochanin A downregulated oncogenes such as RUNX1, BCL2, and MYC while upregulating CHOP (GADD153), CDKN1A (p21), and SQSTM1 (p62), contributing to apoptosis and cell cycle arrest across both cell lines. Notably, Biochanin A downregulated PLK1 and UHRF1 in THP-1 cells, indicating a disruption of mitotic progression and epigenetic regulation. In contrast, in U937 cells, Biochanin A upregulated TXNIP and downregulated CCND2, highlighting the involvement of oxidative stress and G1/S cell cycle arrest. These findings support the potential of Biochanin A as a promising therapeutic candidate for AML through both shared and distinct regulatory pathways.

The prognostic and predictive role of the human equilibrative nucleoside transporter 1 (hENT-1) has emerged in different cancer types, including intrahepatic cholangiocarcinoma (iCCA), but the mechanisms regulating its expression are poorly understood. Here, we investigated the link between p53 status and hENT-1 regulation in 38 iCCA patients and cell line models; the predictive role of p53 status in response to adjuvant gemcitabine was also investigated. A positive association between mutant p53 cells and hENT-1 expression was observed in iCCA tissue samples; furthermore, patients receiving adjuvant gemcitabine and expressing mutant p53 cells > 4% in tumor tissue had a longer disease-free survival (DFS) than patients expressing mutant p53 cells ≤ 4% (median 18.5 vs. 6 months, p = 0.0229). In iCCA cell line models, transient knockdown of mutant p53 resulted in a decrease in hENT-1 mRNA and protein expression; similarly, restoration of wild-type p53 function induced a significant reduction in hENT-1 mRNA and protein expression. Overall, these findings support a role of p53 status in the regulation of hENT-1 expression, suggesting an opposite effect (activating versus repressive) of mutant and wild-type p53 protein. Furthermore, although the present study should be considered as preliminary, our findings suggest a predictive role of p53 status in iCCA patients treated with gemcitabine, thus deserving future investigations in additional cohorts of cancer patients.

Delta-9-tetrahydrocannabinol (Δ-9-THC or THC), the primary psychoactive constituent of cannabis, can lead to adverse health conditions, including mental health issues, brain impairment, and cardiac and respiratory problems. The amount of THC in cannabis has steadily climbed over the past few decades, with today's cannabis having three times the concentration of THC compared to 25 years ago. Inhalation is a major route of exposure, allowing substances to enter the body via the respiratory tract. THC exposure causes cell death in the airway epithelium; however, the molecular underpinning of THC exposure-induced bronchial epithelial cell death is not clearly understood. To address the mechanisms involved in this process, the present study examined the cell viability, oxidative stress, lipid peroxidation, and transcriptional alterations caused by various concentrations of Δ-9-THC (0, 800, 1000, 1200, and 1500 ng/mL) in a human bronchial epithelial cell line (BEAS-2B) in vitro. Δ-9-THC exposure caused a significant dose-dependent decrease in cell viability after 24 h exposure. Transcriptome analysis showed a distinct dose-dependent response. HIF-1 signaling, ferroptosis, AMPK signaling, and immunogenic pathways were activated by Δ-9-THC-upregulated genes. Glutathione and fatty acid metabolic pathways were significantly altered by Δ-9-THC-dependent downregulated genes. Ingenuity Pathway Analysis (IPA) revealed several top canonical pathways altered by Δ-9-THC exposure, including ferroptosis, NRF-2-mediated oxidative stress response, caveolar-mediated endocytosis (loss of cell adhesion to the substrate), tumor microenvironment, HIF1alpha signaling, and the unfolded protein response pathway. Δ-9-THC-induced cell death was ameliorated by inhibiting the ferroptosis pathway, whereas treatments with ferroptosis agonist exacerbated the cell death process, suggesting that Δ-9-THC-induced bronchial epithelial cell death potentially involves the ferroptosis pathway.

Foxtail millet (Setaria italica L.), a representative C4 species, is recognized for its efficient nutrient utilization and robust abiotic stress responses. However, the molecular mechanisms mediating its tolerance to biotic stresses are poorly understood. In this study, we investigated the root transcriptomic response of foxtail millet to the damage-associated molecular pattern (DAMP), the plant elicitor peptide 1 (Pep1). Transcriptome analysis of Pep1-treated roots identified 401 differentially expressed genes (DEGs), comprising 144 up-regulated and 257 down-regulated genes. Gene Ontology (GO) enrichment analysis revealed a significant enrichment of 'peroxidase activity'. This finding was corroborated by DAB staining, which confirmed H2O2 accumulation, along with elevated malondialdehyde (MDA) levels, collectively indicating oxidative stress. Notably, Pep1 treatment also resulted in a marked up-regulation of the pathogenesis-related protein 1 (PR1) gene in leaves, suggesting the activation of systemic acquired resistance. Together, these results demonstrate that Pep1 triggers substantial transcriptional reprogramming in roots, induces oxidative stress, and activates systemic defense signaling in foxtail millet.

In fibrotic skeletal muscles, excessive extracellular matrix (ECM) deposition is a result of increased activation and decreased apoptosis of myofibroblasts. The aim of this study is to investigate whether treatment with quercetin, kaempferol or capsaicin can reduce the transforming growth factor-beta 1 (TGF-β1)-induced myofibroblast differentiation and fibrotic ECM expression in differentiated C2C12 cells. Two-day-differentiated C2C12 cells were treated with TGF-β1 for 48 h to induce myofibroblast differentiation. Twenty-four hours before (pre-treatment) and for forty-eight hours with (co-treatment) TGF-β1 treatment, cells were exposed to quercetin (25, 50 µM), kaempferol (10, 25, 50 µM) or capsaicin (25, 50 µM). The immunofluorescence intensity of alpha smooth muscle actin (αSMA) and collagen type I/III gene expression were assessed as myofibroblast markers. MyoD immunofluorescence intensity was measured as a myogenic marker. Co-treatment of TGF-β1 with the phytochemicals was most effective, resulting in a decreased number of αSMA-positive cells (all three compounds), decreased collagen type I (kaempferol, capsaicin) and type III (kaempferol) gene expression, and increased MyoD (kaempferol, capsaicin) protein expression compared to TGF-β1 treatment. This study demonstrates that treatment with quercetin, kaempferol or capsaicin can reduce myofibroblast markers. This suggests a possible anti-fibrotic effect of the phytochemicals in skeletal muscle.

To explore the mechanism by which γ-aminobutyric acid (GABA) regulates the response of different salt-sensitive tomato seedlings under salt stress conditions, we used the previously selected salt-sensitive tomato 'M82' and the salt-tolerant introgression line 'IL-7-5-5'. The following three treatments were set up: (1) a normal nutrient solution concentration as the control, (2) a nutrient solution with 200 mmol·L-1 NaCl, and (3) a nutrient solution with 200 mmol·L-1 NaCl and 35 mmol·L-1 GABA. The concentration of the reactive oxygen species metabolism-related compounds and antioxidant enzyme activity in the leaves of tomato seedlings subjected to the different treatments were measured, and transcriptome and metabolome analyses were conducted. After adding GABA, the SOD, POD, and APX activity in the leaves of the 'M82' seedlings significantly increased, while the GR activity significantly decreased. In the 'IL-7-5-5' seedlings, the CAT, APX, and GR activity significantly increased. The combined results from the transcriptome and metabolome analysis in leaves indicated that in 'M82' seedlings, 52 metabolic pathways were enriched, which included plant signal transduction pathways, phenylpropanoid biosynthesis pathways, and amino sugar and nucleotide sugar metabolism pathways. In the salt-tolerant 'IL-7-5-5' seedling leaves, 59 metabolic pathways were enriched, which included plant signal transduction pathways, amino acid biosynthesis pathways, and carbon metabolism pathways. A further analysis revealed that both varieties had a higher number of differentially enriched genes and differential metabolites belonging to the plant hormone signal transduction and amino acid biosynthesis pathways, indicating that GABA enhances the salt tolerance of tomato seedlings by regulating these two mechanisms.

Azvudine (FNC) is a novel cytidine analogue that is widely used in the treatment of infectious diseases such as AIDS and COVID-19. Previous studies have demonstrated its anticancer activity in various cancer cell lines, including non-Hodgkin's lymphomas and lung adenocarcinoma cell lines. However, its effects on hepatocellular carcinoma (HCC) and the underlying mechanisms remain unclear. This study aimed to investigate the anti-epithelial-mesenchymal transition (anti-EMT) activity of FNC and evaluate its potential application in HCC treatment. We found that FNC significantly inhibits the migration of the liver cancer cell line Huh7 by downregulating key EMT markers, such as matrix metalloproteinases (MMPs) and E-cadherin, at both the transcriptional and protein expression levels. Notably, we found that FNC inhibits HEY proteins, particularly HEY1, a transcriptional regulator of the Notch signalling pathway that is overexpressed in approximately 50% of HCC patients. To identify the primary target of FNC, microscale thermophoresis (MST) and molecular dynamics (MD) simulations were performed, revealing that FNC directly binds to Jagged1. This study provides valuable insights into the therapeutic potential of FNC in HCC treatment and elucidates its underlying mechanisms.

Emergent cancer drug resistance and further metastasis can mainly be attributed to altered expression levels and functional activities of multiple genes of cancer cells under chemotherapy. In response to challenge with anticancer drugs, enhanced ceramide glycosylation catalyzed by glucosylceramide synthase (GCS) confers drug resistance and enrichment with cancer stem cells. p53 mutations, which gain function in tumor progression, are prevalently extant in ovarian cancers. Via integrated gene expression assessments, we characterized GCS-responsive genes in ovarian cancer cells treated with dactinomycin. NCI/ADR-RES cells dominantly expressed a p53 mutant (7 aa deleted in exon-5) and displayed anti-apoptosis; however, silencing GCS expression rendered these cells sensitive to dactinomycin-induced apoptosis. Microarray analyses of NCI/ADR-RES and its GCS transfected sublines found that elevated GCS expression or ceramide glycosylation was associated with altered expression of 41 genes, notably coding for ABCB1, FGF2, ALDH1A3, apolipoprotein E, laminin 2, chemokine ligands, and IL6, with cellular resistance to induced apoptosis and enrichment with cancer stem cells, promoting cancer progression. These findings were further corroborated through integrated genomic analyses of ovarian cancer from The Cancer Genome Atlas (TCGA) and cancer resistance to platinum-based chemotherapy. Altogether, our present study indicates that altered ceramide glycosylation can modulate expression of these GCS-responsive genes and alter cancer cell attributes under chemotherapy.

Opioid use induces neurobiological adaptations throughout mesolimbic brain regions, such as the orbitofrontal cortex (OFC), which mediates decision-making and emotional-cognitive regulation. Previously, we showed that a circular RNA (circRNA) species, rno_circGrin2b_011731 (circGrin2b), is upregulated in the OFC of rats following chronic self-administration (SA) of the opioid heroin. circGrin2b is derived from Grin2b, which encodes the regulatory subunit of the glutamate ionotropic NMDA receptor, GluN2B. However, the upstream regulatory mechanisms of circGrin2b biogenesis and the downstream consequences of circGrin2b dysregulation remain unknown. We hypothesized that opioid-induced elevation of circGrin2b is accompanied by regulation of circRNA biogenesis enzymes, and that circGrin2b may sponge microRNAs (miRNAs), as miRNA sponging is a well-described characteristic of circRNAs. To test these hypotheses, we established an in vitro primary cortical cell culture model to examine alterations in circGrin2b expression following exposure to the opioid morphine. We measured mRNA expression of known circRNA splicing factors and observed significant downregulation of Fused in Sarcoma (Fus), a negative regulator of circRNA biogenesis, following 90 min or 24 h of morphine exposure. Downregulation of Fus at 24 h post-morphine was accompanied by upregulation of circGrin2b and downregulation of miR-26b-3p, a predicted miRNA target of circGrin2b. Luciferase reporter assays confirmed interaction of miR-26b-3p with circGrin2b. Finally, we report a significant negative relationship between circGrin2b and miR-26b-3p expression in the OFC of rats following heroin SA. We conclude that regulation of circGrin2b is an opioid-induced neuroadaptation that may impact downstream signaling of miRNA pathways in the frontal cortex.