NF-κB Transcriptional Activity Research Articles

Duck hepatitis A virus 1-encoded 2B protein disturbs ion and organelle homeostasis to promote NF-κB/NLRP3-mediated inflammatory response

Previous studies by our group and others have highlighted the critical role of hyperinflammation in the pathogenicity of duck hepatitis A virus 1 (DHAV-1), an avian picornavirus that has caused significant devastation in the duck industry worldwide for decades. However, the precise mechanisms by which DHAV-1 infection regulates the inflammatory responses, particularly the production of IL-1β, remain poorly understood. In this study, we demonstrate that DHAV-1 infection triggers NF-κB- and NLRP3 inflammasome-mediated IL-1β production. Mechanistically, DHAV-1 infection, particularly its replication and translation, disrupts cellular homeostasis of Ca2+, K+, ROS and cathepsin, which act cooperatively as assembly signals for NLRP3 inflammasome activation. By screening DHAV-1-encoded proteins, we identified that the viroporin 2B dominates NF-κB as well as NLRP3 inflammasome activation. Mutation analysis revealed that I43 within the 2B protein is the key amino acid for Ca2+ mobilization and subsequent activation of NF-κB transcriptional activity and NLRP3 inflammasome. Moreover, DHAV-1 infection and the 2B protein activate the MAVS- and MyD88-NF-κB pathways by relay, providing the necessary priming signals for NLRP3 inflammasome activation. In summary, our findings elucidate a mechanism through which DHAV-1 triggers inflammatory responses via NF-κB/NLRP3 inflammasome activation, offering new perspectives on DHAV-1 pathogenesis and informing the development of targeted anti-DHAV-1 treatments.

Radiofrequency field inhibits RANKL-induced osteoclast differentiation in RAW264.7 cells via modulating the NF-κB signaling pathway

ABSTRACT In this study, we investigated the inhibitory effects of radiofrequency exposure on RANKL-induced osteoclast differentiation in RAW264.7 cells, along with the underlying mechanisms. RAW264.7 cells were subjected to radiofrequency exposure at three distinct power densities: 50 µW/cm2, 150 µW/cm2, and 450 µW/cm2. The results showed that, among the three dosage levels, exposure to 150 µW/cm2 of radiofrequency radiation significantly reduced the proliferation capacity of RAW264.7 cells. RF exposure at three power densities resulted in significant increases in the level of osteoclast apoptosis and notable decreases in osteoclast differentiation. Notably, the most pronounced effects on apoptosis, differentiation in RAW 264.7 cells were observed at the 150 µW/cm2 power density. These effects were accompanied by concurrent decreases in mRNA and protein levels of osteoclast-specific genes, including RANK, NFATc1, and TRACP. Furthermore, radiofrequency exposure at power density of 150 µW/cm2 induced a significant decrease in cytoplasmic NF-κB protein levels while increasing its nuclear fraction, thereby counteracting the effects of RANKL-induced NF-κB activation. These data suggest that radiofrequency exerts inhibitory properties on RANKL-induced NF-κB transcriptional activity, subsequently indirectly suppressing the expression of downstream NF-κB target genes, such as NFATc1 and TRACP. In conclusion, our study demonstrates that radiofrequency radiation effectively inhibits osteoclast differentiation by modulating the NF-κB signaling pathway. These findings have important implications for potential therapeutic interventions in osteoporosis.

SPRED3 regulates the NF-κB signaling pathway in thyroid cancer and promotes the proliferation

SPRED3 (Sprouty-related EVH1 domain containing 3) mutants are depicted in various cancers, however, nothing is known about its biofunction in thyroid cancer (THCA). Bioinformatic analyses were conducted to ascertain the level of SPRED3 expression in THCA tissues and its importance in the prognosis of THCA patients. Flag-SPRED3 plasmid and SPRED3-knockout vector were developed to overexpress or deplete the SPRED3 expression in THCA cells. The function of SPRED3 on THCA cell proliferation was examined using the colony formation assay and CCK8 assay. The effect of SPRED3 expression on the transcriptional activity of NF-κB was also examined using luciferase reporter assays. High SPRED3 expression was associated with unfavorable clinical outcomes, advanced tumor characteristics, and traditional molecular markers of papillary thyroid cancer in THCA patients. Genetic analysis revealed differences in mutation rates in key genes between SPRED3-high and SPRED3-low THCA cases. It is also revealed that SPRED3 influenced the immune microenvironment, with increased stromal and immune scores and altered immune cell infiltration. Functionally, SPRED3 overexpression enhanced THCA cell viability and colony formation, while its depletion reduced cell growth and proliferation. In vivo experiments in mice confirmed the inhibitory effect of SPRED3 depletion on tumor growth. Mechanically, we found that SPRED3 activated the NF-κB signaling. For the first time, we found that SPRED3 promotes THCA cell proliferation via the NF-κB signaling pathway. This finding may provide insight into SPRED3’s prognostic potential in thyroid cancer and provide the rationale for SPRED3-targeted druggable interventions.

Monoacylglycerol lipase blockades the senescence-associated secretory phenotype by interfering with NF-κB activation and promotes docetaxel efficacy in prostate cancer.

Metabolic reprogramming and cellular senescence greatly contribute to cancer relapse and recurrence. In aging and treated prostate, persistent accumulating senescence-associated secretory phenotype (SASP) of cancer cells often limits the overall survival of patients. Novel strategic therapy with monoacylglycerol lipase (MGLL) upregulation that counters the cellular and docetaxel induced SASP might overcome this clinical challenge in prostate cancer (PCa). With primary comparative expression and survival analysis screening of fatty acid (FA) metabolism signature genes in the TCGA PCa dataset and our single center cohort, MGLL was detected to be downregulated in malignancy prostate tissues and its low expression predicted worse progression-free and overall survival. Functionally, overexpression of MGLL mainly suppresses NF-κB-driven SASP (N-SASP) which mostly restricts the cancer cell paracrine and autocrine tumorigenic manners and the corresponding cellular senescence. Further investigating metabolites, we determined that MGLL constitutive expression prevents lipid accumulation, decreases metabolites preferably, and consequently downregulates ATP levels. Overexpressed MGLL inhibited IκBα phosphorylation, NF-κB p65 phosphorylation, and NF-κB nuclear translocation to deactivate NF-κB transcriptional activities, and be responsible for the repressed N-SASP, partially through reducing ATP levels. Preclinically, combinational treatment with MGLL overexpression and docetaxel chemotherapy dramatically delays tumor progression in mouse models. Taken together, our findings identify MGLL as a switch for lipase-related N-SASP suppression and provide a potential drug candidate for promoting docetaxel efficacy in PCa.

HSP70 promotes pancreatic cancer cell epithelial-mesenchymal transformation and growth via the NF-κB signaling pathway.

To study the effects of HSP70 on proliferation, migration, invasion, and epithelial-mesenchymal transformation (EMT) of pancreatic cancer cells and explore its underlying mechanisms. Pancreatic cancer cell models with either reduced HSP70 or increased HSP70 expression were established. RT-qPCR and Western blot assays were used to determine mRNA and protein levels of HSP70, IKK/IκBa/NF-κB signaling pathway-related genes, and EMT markers. The CCK-8 and cell cloning assays were used to evaluate cell proliferation and cloning abilities. Transwell and wound healing assays were used to assess the invasive and migratory properties of the cells. Effects of NF-κB signaling modulation were explored using an IKK inhibitor (BAY11-7082) and an IKK overexpression vector (pCMV-IKK). Electrophoretic mobility shift assay (EMSA) and luciferase reporter assays were conducted to analyze NF-κB's promoter binding and transcriptional activities. HSP70 knockdown inhibited p-p65 nuclear translocation and reduced the expression of p-p65, p-IKKα/β, p-IκBα, N-cadherin, Vimentin, and Twist. It also decreased NF-κB's promoter binding and transcriptional activities, increased E-cadherin levels, and suppressed pancreatic cancer cell proliferation, cloning, migration, and invasion. In contrast, HSP70 overexpression led to increased expression of p-p65, p-IKKα/β, p-IκBα, N-cadherin, Vimentin, and Twist, decreased E-cadherin levels, and enhanced cell proliferation, cloning, migration, and invasion capabilities. NF-κB signaling pathway modulation reversed EMT changes induced by altered HSP70 expression levels. rhHSP70 also increased p-IKKα/β and p-IκBα protein levels. HSP70 promotes the EMT and enhances pancreatic cancer cell proliferation, migration, and invasion by activating the NF-κB pathway.

NAD+ Metabolism Reprogramming Mediates Irradiation-Induced Immunosuppressive Polarization of Macrophages

Purposeradiotherapy stands as an important complementary treatment for head and neck squamous cell carcinoma (HNSCC), yet it does not invariably result in complete tumor regression. The infiltration of immunosuppressive macrophages is believed to mediate the radiotherapy resistance, which mechanism remains largely unexplored. This study aimed to elucidate the role of immunosuppressive macrophages during radiotherapy and the associated underlying mechanisms. Materials and MethodsMale C3H mice bearing syngeneic SCC-VII tumor were received irradiation (2 × 8Gy). The impact of irradiation on tumor-infiltrating macrophages were assessed. Bone marrow derived macrophages were evaluated in differentiation, proliferation, migration, and inflammatory cytokines after treatment of irradiated tumor culture medium (irCM) and irradiated tumor derived extracellular vesicles (irTEVs). A comprehensive metabolomics profiling of the irTEVs was conducted using liquid chromatography-mass spectrometry, while key metabolites were investigated the mechanism in macrophage in vitro and in vivo. ResultsRadiotherapy on SCC-VII syngeneic graft tumors increased polarization of both M1 and M2 macrophages in tumor microenvironment and drove infiltrated macrophages towards an immunosuppressive phenotype. Irradiation-induced polarization and immunosuppression of macrophages were dependent on irTEVs which delivered an increased amount of nicotinamide (NAM) to macrophages. NAM directly bound to the NF-κB transcriptional activity regulator USP7, through which NAM reduced translocation of NF-κB into the nucleus, thereby decreasing the release of cytokines IL6 and IL8. Increased enzyme activity of nicotinamide phosphoribosyl transferase (NAMPT) which is the rate-limiting enzyme of NAD+ metabolism, contributed to the irradiation-induced accumulation levels of NAM in irradiated HNSCC and irTEVs. Inhibition of NAMPT decreased NAM levels in irTEVs and increased radiotherapy sensitivity through alleviating immunosuppressive function of macrophages. ConclusionsRadiotherapy could induce NAD+ metabolic reprogramming of HNSCC cells, which regulate macrophage towards an immunosuppressive phenotype. Pharmacological targeting NAD+ metabolism might be a promising strategy for radiotherapy sensitization of HNSCC.

UBE2S facilitates glioblastoma progression through activation of the NF-κB pathway via attenuating K11-linked ubiquitination of AKIP1

BackgroundRapid proliferation is a hallmark of glioblastoma multiforme (GBM) and a major contributor to its recurrence. Aberrant ubiquitination has been implicated in various diseases, including cancer. In our preliminary studies, we identified Ubiquitin-conjugating enzyme E2S (UBE2S) as a potential glioma biomarker, exhibiting close associations with glioma grade and protein phosphatase 1, regulatory subunit 105 (Ki67) expression levels. However, the underlying molecular mechanisms remained elusive. NF-κB is an important signaling pathway that promotes GBM proliferation. Direct intervention targeting NF-κB has not yielded the expected results, prompting the exploration of new molecules for regulating NF-κB as a new direction. MethodsThis study employed methods including yeast two-hybrid and immunoprecipitation to uncover the interaction between UBE2S and A kinase interacting protein 1 (AKIP1). Laser confocal microscopy was used to observe the localization of UBE2S and AKIP1. Dual luciferase reporter genes were utilized to observe the activation of NF-κB. ResultsOur findings demonstrate that UBE2S deficiency significantly impedes GBM progression, both in vitro and in vivo. Mechanistically, UBE2S plays a crucial role in recruiting Ubiquitin Specific Peptidase 15 (USP15), facilitating the removal of K11-linked ubiquitination on AKIP1. This action enhances AKIP1 stability within the GBM context. The resulting increase in AKIP1 levels further augments nuclear factor kappa-B (NF-κB) transcriptional activity, leading to the upregulation of downstream genes regulated by the NF-κB pathway, thereby promoting GBM progression. ConclusionsIn summary, our findings reveal the role of the UBE2S/AKIP1-NF-κB axis in regulating GBM progression and provide novel evidence supporting UBE2S as a potential drug target for GBM.

Dihydromyricetin ameliorates diabetic renal fibrosis via regulating SphK1 to suppress the activation of NF-κB pathway

Dihydromyricetin (DHM) is a flavonoid from vine tea with broad pharmacological benefits, which improve inflammation by blocking the NF-κB pathway. A growing body of research indicates that chronic kidney inflammation is vital to the pathogenesis of diabetic renal fibrosis. Sphingosine kinase-1 (SphK1) is a key regulator of diabetic renal inflammation, which triggers the NF-κB pathway. Hence, we evaluated whether DHM regulates diabetic renal inflammatory fibrosis by acting on SphK1. Here, we demonstrated that DHM effectively suppressed the synthesis of fibrotic and inflammatory adhesion factors like ICAM-1, and VCAM-1 in streptozotocin-treated high-fat diet-induced diabetic mice and HG-induced glomerular mesangial cells (GMCs). Moreover, DHM significantly suppressed NF-κB pathway activation and reduced SphK1 activity and protein expression under diabetic conditions. Mechanistically, the results of molecular docking, molecular dynamics simulation, and cellular thermal shift assay revealed that DHM stably bound to the binding pocket of SphK1, thereby reducing sphingosine-1-phosphate content and SphK1 enzymatic activity, which ultimately inhibited NF-κB DNA binding, transcriptional activity, and nuclear translocation. In conclusion, our data suggested that DHM inhibited SphK1 phosphorylation to prevent NF-κB activation thus ameliorating diabetic renal fibrosis. This supported the clinical use and further drug development of DHM as a potential candidate for treating diabetic renal fibrosis.

Multilevel Regulation of NF-κB Signaling by NSD2 Suppresses Kras-Driven Pancreatic Tumorigenesis.

Pancreatic ductal adenocarcinoma (PDAC) is a clinically challenging cancer with a dismal overall prognosis. NSD2 is an H3K36-specific di-methyltransferase that has been reported to play a crucial role in promoting tumorigenesis. Here, the study demonstrates that NSD2 acts as a putative tumor suppressor in Kras-driven pancreatic tumorigenesis. NSD2 restrains the mice from inflammation and Kras-induced ductal metaplasia, while NSD2 loss facilitates pancreatic tumorigenesis. Mechanistically, NSD2-mediated H3K36me2 promotes the expression of IκBα, which inhibits the phosphorylation of p65 and NF-κB nuclear translocation. More importantly, NSD2 interacts with the DNA binding domain of p65, attenuating NF-κB transcriptional activity. Furthermore, inhibition of NF-κB signaling relieves the symptoms of Nsd2-deficient mice and sensitizes Nsd2-null PDAC to gemcitabine. Clinically, NSD2 expression decreased in PDAC patients and negatively correlated to nuclear p65 expression. Together, the study reveals the important tumor suppressor role of NSD2 and multiple mechanisms by which NSD2 suppresses both p65 phosphorylation and downstream transcriptional activity during pancreatic tumorigenesis. This study opens therapeutic opportunities for PDAC patients with NSD2 low/loss by combined treatment with gemcitabine and NF-κBi.

Decline in corepressor CNOT1 in the pregnant myometrium near term impairs progesterone receptor function and increases contractile gene expression

Progesterone (P4), acting via its nuclear receptor (PR), is critical for pregnancy maintenance by suppressing proinflammatory and contraction-associated protein (CAP)/contractile genes in the myometrium. P4/PR partially exerts these effects by tethering to NF-κB bound to their promoters, thereby decreasing NF-κB transcriptional activity. However, the underlying mechanisms whereby P4/PR interaction blocks proinflammatory and CAP gene expression are not fully understood. Herein, we characterized CCR-NOT transcription complex subunit 1 (CNOT1) as a P4-induced corepressor that also interacts within the same chromatin complex as PR-B. In mouse myometrium increased expression of CAP genes Oxtr and Cx43 at term coincided with a marked decline in expression and binding of endogenous CNOT1 to NF-κB-response elements within the Oxtr and Cx43 promoters. Increased CAP gene expression was accompanied by a pronounced decrease in the enrichment of repressive histone marks and an increase in the enrichment of active histone marks to this genomic region. These changes in histone modification were associated with changes in the expression of corresponding histone-modifying enzymes. Myometrial tissues from P4-treated 18.5 dpc pregnant mice manifested increased Cnot1 expression at 18.5 dpc, compared to vehicle-treated controls. In hTERT-HM cells, P4 treatment enhanced CNOT1 expression and its recruitment to NF-κB-response elements within the CX43 and OXTR promoter regions. Furthermore, knockdown of CNOT1 significantly increased the expression of contractile genes. These novel findings suggest that decreased expression and binding of the transcriptional corepressor CNOT1 at the chromatin level near term and associated changes in histone modifications at the OXTR and CX43 promoters contribute to the induction of myometrial contractility leading to parturition.

A Novel Ectodysplasin a Gene mutation of X-Linked Hypohidrotic Ectodermal Dysplasia.

Hypohidrotic ectodermal dysplasia (HED) is a genetic disorder that influences structures of ectodermal origin, such as teeth, hair, and sweat glands. Compared with autosomal recessive and dominant modes of inheritance, the X-linked HED (XLHED) characterized by Hypodontia/Oligodontia teeth, Absent/sparse hair, Anhidrosis/hypohidrosis, and characteristic facial features, is the most frequent and its primary cause is the mutation of ectodysplasin A (EDA) gene. This research aimed to expound the clinical and molecular features of a Chinese male with XLHED and to summarize and compare several previous findings. Genomic DNA was obtained from the peripheral blood of the proband and his family members, then Sanger sequencing was used to perform a mutational analysis of EDA. Real-time quantitative PCR and Western blotting were used to detect EDA expression. The transcriptional activity of NF-κB was detected using a luciferase assay. The probandwith XLHED was identified a novel EDA mutation, c.1119G>C(p.M373I), that affected the molecular analysis of transmembrane protein exon8 mutations, inherited from the mother. He showed a severe multiple-tooth loss, with over 20 permanent teeth missing and sparse hair and eyebrows, dry, thin, and itching skin. Furthermore, his sweating function was abnormal to a certain extent. The functional study showed that this novel mutant led to a significant decrease in the EDA expression level and transcriptional activity of NF-κB. Our findings extend the range of EDA mutations in XLHED patients, which provides the basis and idea for further exploring the pathogenesis of XLHED.

Synthesis and biological evaluation of chrysin derivatives containing α-lipoic acid for the treatment of inflammatory bowel disease.

This study introduces newly discovered chrysin derivatives that show potential as candidate molecules for treating inflammatory bowel disease (IBD). Compound 4b, among the synthesized compounds, displayed significant inhibitory effects on monocyte adhesion to colon epithelium induced by TNF-α, with an IC50 value of 4.71μM. Further mechanistic studies demonstrated that 4b inhibits the production of reactive oxygen species (ROS) and downregulates the expression of ICAM-1 and MCP-1, key molecules involved in monocyte-epithelial adhesion, as well as the transcriptional activity of NF-κB. In vivo experiments have shown that compound 4b exhibits a dose-dependent inhibition of 2, 4, 6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats, thereby validating its effectiveness as a colitis inhibitor in animal models. These results indicate that 4b shows considerable promise as a therapeutic agent for managing IBD.

Anti-Inflammatory Activity of Pyrazolo[1,5-a]quinazolines.

Chronic inflammation contributes to a number of diseases. Therefore, control of the inflammatory response is an important therapeutic goal. To identify novel anti-inflammatory compounds, we synthesized and screened a library of 80 pyrazolo[1,5-a]quinazoline compounds and related derivatives. Screening of these compounds for their ability to inhibit lipopolysaccharide (LPS)-induced nuclear factor κB (NF-κB) transcriptional activity in human THP-1Blue monocytic cells identified 13 compounds with anti-inflammatory activity (IC50 < 50 µM) in a cell-based test system, with two of the most potent being compounds 13i (5-[(4-sulfamoylbenzyl)oxy]pyrazolo[1,5-a]quinazoline-3-carboxamide) and 16 (5-[(4-(methylsulfinyl)benzyloxy]pyrazolo[1,5-a]quinazoline-3-carboxamide). Pharmacophore mapping of potential targets predicted that 13i and 16 may be ligands for three mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase 2 (ERK2), p38α, and c-Jun N-terminal kinase 3 (JNK3). Indeed, molecular modeling supported that these compounds could effectively bind to ERK2, p38α, and JNK3, with the highest complementarity to JNK3. The key residues of JNK3 important for this binding were identified. Moreover, compounds 13i and 16 exhibited micromolar binding affinities for JNK1, JNK2, and JNK3. Thus, our results demonstrate the potential for developing lead anti-inflammatory drugs based on the pyrazolo[1,5-a]quinazoline and related scaffolds that are targeted toward MAPKs.

Abstract A015: Novel genetic driver for the genesis of muscle invasion in bladder cancer

Abstract Non-muscle invasive bladder cancer (NMIBC) is a heterogeneous type of urothelial carcinoma with a substantial risk (&amp;gt;50%) of tumor progression and muscle invasion. Our sequential studies uniquely unveiled the availability of Retinal Degeneration Protein 3 (RD3) in human adult/fetal tissues and recognized its functional significance in tumor evolution. Herein, we investigated the relevance of RD3 in coordinating de novo MIBC from NMIBC. Compared to the low-grade tumor, RD3 is significantly lost (mRNA, qPCR; protein, ELISA) in grade III and IV patient derived NMIBC cells. In a cohort of (n=55) NMIBC patients, RD3-loss associated with increased tumor invasive potential (complete loss in highly invasive T4), metastasis (vs. primary tumors), therapy pressure (insignificant levels in progressive disease that defies therapy), disease recurrence, and death (custom archived TMA with automated RD3 IHC).Crucially, we observed a significant low-is-worse association to overall survival (p=7.30E-03, hazard ratio (HR) of 5.161), relapse-free survival (p=4.464E-02, HR = 2.328), and progression-free survival (p=7.00E-0.4, HR = 3.264). Further, radio-resistant cells exposed to fractionated irradiation (FIR, 2Gy/Day for 5 days) to a total dose of 10 or 20Gy displayed a dose dependent loss of RD3 recognizing an ongoing acquisition of RD3-loss with therapy pressure. More interestingly, Grade I or III bystander cells (BSE) co-cultured with FIR-exposed cells displayed anew acquisition of RD3-loss and displayed tumor grade-dependent increase (vs. mock-irradiated) in NFkB transcriptional activity (EMSA) and the activation of NFkB trans-activated pro-survival molecules (QPCR profiling of 89 NFkB targets). Together, these results clearly depict that RD3 regulates NMIBC disease pathogenesis, dissemination, acquired loss of RD3 with therapy pressure and further implies its role in the evolution of de novo MIBC from NMIBC. Funding: DOD CA-210339, OCAST-HR19-045, NIH-P20GM103639, NIH-NCI-P30CA225520 and TSET-R23-03. Citation Format: Sreenidhi Mohanvelu, Poorvi Subramanian, Sabir Salim, Dinesh Babu Somasundaram, Sheeja Aravindan, Natarajan Aravindan. Novel genetic driver for the genesis of muscle invasion in bladder cancer [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(10_Suppl):Abstract nr A015.

Potato protein hydrolysate inhibits RANKL-induced osteoclast development by inhibiting osteoclastogenic genes via the NF-κB/MAPKs signaling pathways.

In recent times, there has been growing attention towards exploring the nutritional and functional aspects of potato protein, along with its diverse applications. In the present study, we examined the anti-osteoclast properties of potato protein hydrolysate (PP902) in vitro. Murine macrophages (RAW264.7) were differentiated into osteoclasts by receptor activator of nuclear factor-κB ligand (RANKL), and PP902 was examined for its inhibitory effect. Initially, treatment with PP902 was found to significantly prevent RANKL-induced morphological changes in macrophage cells, as determined by tartrate-resistant acid phosphatase (TRAP) staining analysis. This notion was further supported by F-actin analysis using a confocal microscope. Furthermore, PP902 treatment effectively and dose-dependently down-regulated the expression of RANKL-induced osteoclastogenic marker genes, including TRAP, CTR, RANK, NFATc1, OC-STAMP, and c-Fos. These inhibitory effects were associated with suppressing NF-κB transcriptional activation and subsequent reduced nuclear translocation. The decrease in NF-κB activity resulted from reduced activation of its upstream kinases, including I-κBα and IKKα. Moreover, PP902 significantly inhibited RANKL-induced p38MAPK and ERK1/2 activities. Nevertheless, PP902 treatment prevents RANKL-induced intracellular reactive oxygen species generation via increased HO-1 activity. The combined antioxidant and anti-inflammatory effects of PP902 resulted in significant suppression of osteoclastogenesis, suggesting its potential as an adjuvant therapy for osteoclast-related diseases.

Abstract 4557: Overexpressed CPAP promotes cancer stemness and enhances chemo-resistance in HCC

Abstract Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and is highly resistant to chemotherapy and targeted therapy. It was reported that HCC cancer stem cells (CSCs) are involved in chemo-drug resistance by regulating multidrug resistance (MDR) gene expression, such as ABC transporters. Our previous reports indicated that CPAP, a centrosomal protein, can promote HCC progression by up-regulating NF-κB and STAT3 transcriptional activities. Here, we demonstrated that overexpressed CPAP can increase cancer stemness features and CSCs-derived sorafenib resistance in HCC by up-regulating the transcriptional activities of NF-κB and β-catenin. Importantly, CPAP stably expressed HCC spheroids are significantly resistance to sorafenib in vitro and in vivo. Our results suggested that CD24 and ABCG2 are two potential downstream effectors in CPAP overexpressed HCC. CPAP can transcriptionally up-regulate CD24 and ABCG2 expression via Wnt/β-catenin and NF-κB signaling pathways, respectively; high CPAP/ABCG2/CD24 expression levels are negatively correlated with disease-specific survival rates in HCC patients. Combined treatment with sorafenib and Wnt/β-catenin pathway inhibitor PRI-724 significantly inhibited CPAP-overexpressing Hep3B spheroids-derived tumor growth in a xenograft mouse model. Our study highlights the oncogenic role of CPAP in promoting CSCs-induced sorafenib resistance in HCC and provides insights into potential therapeutic strategies. Citation Format: Liang-Yi Hung. Overexpressed CPAP promotes cancer stemness and enhances chemo-resistance in HCC [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 4557.

Abstract 5545: FADD activation renders hepatocellular carcinoma sensitive to immune checkpoint blockade by turning cold tumors hot

Abstract The heterogenicity of hepatocellular carcinoma (HCC) remains a key obstacle in turning the majority of ‘immune-cold’ tumors ‘hot’ for effective immune checkpoint blockade (ICB) therapy. Through studying the naturally-existed ‘hot’ HCC variant lymphoepithelioma-like (LEL)-HCC by RNA and whole exome sequencing analysis, we identified fas-associated death domain (FADD) as one of the top differentially expressed genes that associated with high tumoral CD8+T cell abundance. Of note, FADD upregulation was also observed in HCC patients with better ICB responsiveness. As FADD was mainly expressed in tumor cells from HCC by scRNAseq analysis, we constructed Fadd knockout stable cells using murine HCC cell lines. Interestingly, CRISPR knockout of tumoral Fadd led to increased tumor weights in immunocompetent but not immunodeficient mice, accompanied with decreased tumoral CD8+T cells. Mechanistically, FADD phosphorylation promoted NF-κB transcriptional activity to increase CCL5 secretion from HCC cells via interacting with its nuclear binding partners Src-associated-substrate-during-mitosis-of-68kDa/KH domain containing, RNA binding, signal transduction associated 1 (Sam68/KHDRBS1) and lysine (K)-specific methyltransferase 2D (KMT2D), thus directing CD8+T cell tumor infiltration. In addition, anti-PD1 triggered FADD phosphorylation via IFN-γ and TNF-ɑ release from CD8+T cells in ICB-sensitive but not resistant tumors. Most importantly, sequential FADD activation via genetic and pharmacologic approaches could re-sensitize the therapeutic efficacy of anti-programmed death 1 (PD1) antibody in ICB-resistant orthotopic and spontaneous HCC models by turning cold tumors hot. Taken together, our findings reveal a key molecular feature of ICB-responsive hot tumors that may guide the development of sequential combinatory immunotherapies for the majority of HCC patients with low responsiveness to ICB monotherapy. This project is supported by the University Grants Committee through General Research Fund (24110323, 14107622, 14104820) and the Health and Medical Research Fund (07180556). Citation Format: Jingying Zhou, Jiahuan Lu. FADD activation renders hepatocellular carcinoma sensitive to immune checkpoint blockade by turning cold tumors hot [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 5545.

Naringenin Inhibits Acid Sphingomyelinase-Mediated Membrane Raft Clustering to Reduce NADPH Oxidase Activation and Vascular Inflammation.

Macrophage inflammation and oxidative stress promote atherosclerosis progression. Naringenin is a naturally occurring flavonoid with antiatherosclerotic properties. Here, we elucidated the effects of naringenin on monocyte/macrophage endothelial infiltration and vascular inflammation. We found naringenin inhibited oxidized low-density lipoprotein (oxLDL)-induced pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α toward an M2 macrophage phenotype and inhibited oxLDL-induced TLR4 (Toll-like receptor 4) membrane translocation and downstream NF-κB transcriptional activity. Results from flow cytometric analysis showed that naringenin reduced monocyte/macrophage infiltration in the aorta of high-fat-diet-treated ApoE-deficient mice. The aortic cytokine levels were also inhibited in naringenin-treated mice. Further, we found that naringenin reduced lipid raft clustering and acid sphingomyelinase (ASMase) membrane gathering and inhibited the TLR4 and NADPH oxidase subunit p47phox membrane recruitment, which reduced the inflammatory response. Recombinant ASMase treatment or overexpression of ASMase abolished the naringenin function and activated macrophage and vascular inflammation. We conclude that naringenin inhibits ASMase-mediated lipid raft redox signaling to attenuate macrophage activation and vascular inflammation.

Abstract 5432: The role of nuclear factorκB-inducing kinase in ovarian cancer stem cells, chemoresistance, and relapse

Abstract Ovarian cancer is the most lethal gynecological cancer in the United States, largely due to its high relapse rates. Research suggests these high relapse rates are due to cancer stem-like cells (CSCs), a subpopulation of tumor cells that are resistant to chemotherapy and have enhanced tumor-initiation capacity. Post-treatment, CSCs self-renew to re-establish new tumors, leading to recurrent disease that is now resistant to chemotherapy. Given that over-expression of NF-κB has been linked to CSCs, cancer progression, and chemoresistance in various tumors, including ovarian, studies uncovering the mechanisms of this pathway are needed to develop novel therapeutics for ovarian cancer treatment. The upstream activator of the alternative NF-κB pathway, Nuclear Factor κB-inducing Kinase (NIK), could be an enticing target for eliminating CSCs, however its function in these cells is not established. In our current studies, we show that HGSOC cells grown as CSC-enriching 3D spheroids have increased NIK expression and activity relative to monolayer cultured cells. Moreover, cells expressing CSC markers (CD117+/CD133+), have increased NIK gene expression, further supporting an association between NIK and CSC maintenance. Upon treatment with chemotherapies carboplatin and paclitaxel, NIK gene expression increased in the surviving population, indicating a role in chemoresistance. Knockdown of NIK using siRNA led to changes in alternative NF-kB transcriptional activity and higher sensitivity to carboplatin and paclitaxel relative to vehicle controls. Current studies are evaluating the role of NIK in tumor-initiation capacity, asymmetric division, proliferation, and changes in expression of stemness genes. Lastly, an in vivo relapse model will test the feasibility of using a NIK inhibitor following chemotherapy to prevent relapse and prolong survival. Findings from this work will further define the role of NF-kB pathway components in facilitating CSCs survival and re-establishment of tumors and identify a new potential target for eliminating CSCs in ovarian cancer. Citation Format: Cassidy C. Lucht, Mikella Robinson, Samuel F. Gilbert, Omar Lujano Olazaba, Carrie D. House. The role of nuclear factorκB-inducing kinase in ovarian cancer stem cells, chemoresistance, and relapse [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 5432.

HIPK2 C-terminal domain inhibits NF-κB signaling and renal inflammation in kidney injury.

HIPK2 is a multifunctional kinase that acts as a key pathogenic mediator of chronic kidney disease and fibrosis. It acts as a central effector of multiple signaling pathways implicated in kidney injury, such as TGF-β/Smad3-mediated extracellular matrix accumulation, NF-κB-mediated inflammation, and p53-mediated apoptosis. Thus, a better understanding of the specific HIPK2 regions necessary for distinct downstream pathway activation is critical for optimal drug development for CKD. Our study now shows that caspase-6-mediated removal of the C-terminal region of HIPK2 (HIPK2-CT) lead to hyperactive p65 NF-κB transcriptional response in kidney cells. In contrast, the expression of cleaved HIPK2-CT fragment could restrain the NF-κB transcriptional activity by cytoplasmic sequestration of p65 and the attenuation of IκBα degradation. Therefore, we examined whether HIPK2-CT expression can be exploited to restrain renal inflammation in vivo. The induction of HIPK2-CT overexpression in kidney tubular cells attenuated p65 nuclear translocation, expression of inflammatory cytokines, and macrophage infiltration in the kidneys of mice with unilateral ureteral obstruction and LPS-induced acute kidney injury. Collectively, our findings indicate that the HIPK2-CT is involved in the regulation of nuclear NF-κB transcriptional activity and that HIPK2-CT or its analogs could be further exploited as potential antiinflammatory agents to treat kidney disease.