Accurate identification of tumor-derived exosomes is crucial for advancing cancer diagnosis and therapies. However, distinguishing tumor-derived exosomes is challenging due to the heterogeneity of exosomes, which reflect different sizes and cells of origin. To address this challenge, we introduce the
Recent studies have indicated that using statins to inhibit the mevalonate pathway induces mutant p53 degradation by impairing the interaction of mutant p53 with DnaJ subfamily A member 1 (DNAJA1). However, the role of the C-terminus of DNAJA1 with a CAAX box for farnesylation in the binding, folding, and translocation of client proteins such as mutant p53 is not known. In the present study, we used a genetically engineered mouse model of pancreatic carcinoma and showed that atorvastatin significantly increased animal survival and inhibited pancreatic carcinogenesis. There was a dramatic decrease in mutant p53 protein accumulation in the pancreatic acini, pancreas intraepithelial neoplasia lesions, and adenocarcinoma. Supplementation with farnesyl pyrophosphate, a substrate for protein farnesylation, rescued atorvastatin-induced mutant p53 degradation in pancreatic cancer cells. Tipifarnib, a farnesyltransferase inhibitor, mirrored atorvastatin's effects on mutant p53, degraded mutant p53 in a dose-dependent manner, and converted farnesylated DNAJA1 into unfarnesylated DNAJA1. Farnesyltransferase gene knockdown also significantly promoted mutant p53 degradation. Coimmunoprecipitation either by an anti-DNAJA1 or p53 antibody confirmed the direct interaction of mutant p53 and DNAJA1 and higher doses of atorvastatin treatments converted more farnesylated DNAJA1 into unfarnesylated DNAJA1 with much less mutant p53 pulled down by DNAJA1. Strikingly, C394S mutant DNAJA1, in which the cysteine of the CAAX box was mutated to serine, was no longer able to be farnesylated and lost the ability to maintain mutant p53 stabilization. Our results show that farnesylated DNAJA1 is a crucial chaperone in maintaining mutant p53 stabilization and targeting farnesylated DNAJA1 by atorvastatin will be critical for inhibiting p53 mutant cancer.
Anti‐inflammatory and anti‐carcinogenic effects of ω‐3 polyunsaturated fatty acid (PUFAs) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), etc., are well known; but the mechanism/s remains unclear. Of the three metabolic pathways {Cyclooxygenase (COX), Lipooxygenase (LOX) and Cyto‐p450 (CYP)}, ω‐3 PUFAs are predominantly metabolized by CYP epoxygenase/s, leading to an accumulation of ω‐3 epoxy fatty acid (ω‐3 epoxides); and ω‐3 PUFAs are poor substrates of COX and LOX. However, under physiologic conditions, these ω‐3 epoxides are quickly inactivated by soluble epoxide hydrolase (sEH) to the diol products, and a sEH inhibitor appears crucial to stabilizing/enhancing these ω‐3 epoxides actions. In this study, using a transplantable murine PK03 pancreatic carcinoma model which carried mutant Kras gene, we have performed three animal experiments using Fat‐1 transgenic, sEH (−/−), and C57BL/6J mice subcutaneously implanted with a murine PK03 pancreatic carcinoma cells treated with or without sEH inhibitor and fed with either AIN‐76A or AIN‐76A diet supplemented with ω‐3 PUFAs. Aims of this study are to determine 1) if sEH gene knockout or inhibition stabilize the epoxide metabolites of ω‐3/ω‐6 PUFAs, 2) if sEH gene knockout or inhibition has more potent effects on inhibiting pancreatic cancer growth via enhancing the ω‐3 epoxide metabolites, and 3) potential molecular targets on mutant Kras mediated signaling, angiogenesis and inflammation. The significant findings were summarized as follows: in Fat‐1 mice treated with sEH inhibitor t ‐AUCB or sEH (−/−) mice fed with AIN‐76A diet supplemented with ω‐3 PUFAs or C57BL/6J mice treated with sEH inhibitor and AIN‐76A diet supplemented with ω‐3 PUFAs, compared to fat‐1 mice without t ‐AUCB treatment or sEH(−/−) mice fed with AIN‐76A diet, or C57BL/6J mice fed AIN‐76A diet, i) the size and tumor volume of xenograft PK03 pancreatic carcinoma was significantly inhibited ii) more glandular formation/well differentiation in the treated PK03 pancreatic carcinoma was observed by histopathologic analysis, iii) significant less inflammatory cell infiltrates and cell proliferation labeled immunohistochemically by anti‐myeloperoxidase and ki‐67 antibodies, as well as significant increased caspase‐3 labeled apoptosis and significant reduced intratumoral angiogenesis labeled by CD34 antibody were observed in the treated PK03 pancreatic carcinoma; iv) Western blot analysis showed a significant inhibition of mutant Kras‐activated signals including phosphorylated cRaf, MEK and ERK. Eicosanoic acid metabolic profiling analyzed by LC/MSMS method revealed a significant increase of the ratios of Epoxy to DiHDPE for DHA and EPA, and Epoxy/DiHOME for ARA and LA, as well as a significant increase of epoxy metabolites of DHA, EPA, ARA and LA. These results indicate that ω‐3 PUFAs supplementation together with sEH inhibition plays an important role in inhibiting pancreatic carcinogenesis mainly via enhancing the epoxy metabolites, and are highly potential approach for preventing pancreatic cancer. Support or Funding Information Supported by NIH R01 DK107767 to Dr. Guang‐Yu Yang. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Colorectal cancer (CRC) is one of the most lethal and prevalent malignancies. While the overexpression of pioneer factor GATA6 in CRC has been linked with metastasis, its role in genome-wide gene expression dysregulation remains unclear. Through studies of primary human CRC tissues and analysis of the TCGA data, we found that GATA6 preferentially binds at CRC-specific active enhancers, with enrichment at enhancer-promoter loop anchors. GATA6 protein also physically interacts with CTCF, suggesting its critical role in 3D genome organization. The ablation of GATA6 through AID and CRISPR systems severely impaired cancer cell clonogenicity and proliferation. Mechanistically, GATA6 knockout induced global loss of CRC-specific open chromatins and extensive alterations of critical enhancer-promoter interactions for CRC oncogenes. Last, we showed that GATA6 knockout greatly reduced tumor growth and improved survival in mice. Together, we revealed a previously unidentified mechanism by which GATA6 contributes to the pathogenesis of colorectal cancer.
Transmural fibrosis and stricture formation are key pathogenic processes for Crohn's disease that underlies clinical refractoriness, resulting in severe morbidity. The mechanisms for fibroplasia in Crohn's are not fully elucidated. In this study, we identified a cohort of refractory Crohn's disease with surgically resected bowel specimens including cases with bowel stricture and age-/sex-matched refractory disease without bowel stricture. Via immunohistochemistry, density and distribution of IgG4+ plasma cells in resected cases were analyzed. The histologic severity of fibrosis and association with gross evidence of stricture formation and IgG4+ plasma cells were comprehensively analyzed. Our results showed that density of IgG4+ plasma cells/high-power field (IgG4+ PCs/HPF) was significantly associated with increasing histologic fibrosis score (15 IgG4+ PCs/HPF in specimens with fibrosis score 0 vs 31 IgG4+ PC/HPF in fibrosis score 2 and 3, P = .039). Patients with gross evidence of stricture had significantly higher fibrosis scores compared to those without gross evidence of stricture ( P = .044). There was a trend that mean IgG4+ plasma cell count was higher in Crohn's disease with gross stricture formation ( P = .26), although it did not reach statistical significance (likely due to multiple pathogenesis events involved in bowel stricture formation besides IgG4+ plasma cells; such as transmural fibrosis, muscular hypertrophy, transmural ulcer/scar formation, and muscular–neural dysfunction). Our findings indicate IgG4+ plasma cells are associated with increasing histologic fibrosis in Crohn's. Further research is needed to establish a role for IgG4+ plasma cells in fibroplasia with an eye toward potential medical therapies targeting IgG4+ plasma cells to prevent transmural fibrosis.
Cytochrome P450 epoxygenase is a major enzyme involved in the metabolism of ω-3 polyunsaturated fatty acids (PUFAs) to produce biologically active ω-3 epoxy fatty acids (ω-3 epoxides). In general, all epoxy PUFAs including ω-3 epoxides are quickly metabolized/inactivated by soluble epoxide hydrolase (sEH) to form diol products. The aims of this study were to determine the effect and mechanism of fat-1 transgene, and ω-3 PUFA combined with sEH gene knockout or inhibitor on inhibiting pancreatic cancer and the related mechanisms involved.PK03-mutant KrasG12D murine pancreatic carcinoma cells were inoculated into mouse models including fat-1, sEH-/- and C57BL/6J mice. The mice were fed with AIN-76A diet with or without ω-3 PUFA supplementation or treated with sEH inhibitor. In addition to tumor growth (tumor size and weight), cell proliferation, mutant Kras-mediated signaling, inflammatory reaction and angiogenesis were analyzed immunohisto-chemically and by western blot assay. ω-3 PUFA metabolism, particularly focusing on ω-3 epoxy fatty acids (ω-3 epoxides), was measured using a liquid chromatography with tandem mass spectrometry (LC-MS/MS) approach.Significant decreases of weight and size of the PK03 pancreatic carcinoma were observed in the fat-1 transgenic mice treated with sEH inhibitor compared to those of C57BL/6J control mice fed with AIN-76A diet (weight: 0.28±0.04 g vs. 0.58±0.06 g; size: 187.0±17.5 mm3 vs. 519.3±60.6 mm3). In a separate experiment, sEH-/- mice fed ω-3 PUFA supplement and C57BL/6J mice treated with sEH inhibitor and fed ω-3 PUFA supplement exhibited a significant reduction in the weight and size of the pancreatic carcinoma compared to C57BL/6J control mice (weight: 0.26±.26 g and 0.39±.39 g vs. 0.69±0.11 g, respectively; size: 274.2±36.2 mm3 and 296.4±99.8 mm3 vs. 612.6±117.8 mm3, respectively). Moreover, compared to the pancreatic tumors in C57BL/6J control mice, the tumors in fat-1 transgenic mice treated with sEH inhibitor showed a significant less inflammatory cell infiltrate (62.6±9.2/HPF (high power field) vs. 8.0±1.2/HPF), tumor cell proliferation (48.5±1.7% vs. 16.5±1.6%), and angiogenesis (micro-vessel density (MVD): 35.0±1.0 vs. 11.1±0.5) immunohistochemically, as well as significantly increased caspase-3 labeled apoptosis (0.44±0.06% vs. 0.69±0.06%, respectively). Using western blot approach, significant inhibition of mutant Kras-activated signals including phosphorylated Serine/threonine kinases (cRAF), Mitogen-activated protein kinase kinase (MEK), and extracellular signal-regulated kinase (ERK) were identified in pancreatic carcinoma of fat-1 transgenic mice treated with sEH inhibitor. Eicosanoic acid metabolic profiling of the serum specimens detected a significant increase of the ratios of epoxides to dihydroxy fatty acid (DiHDPE) for docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and epoxides/dihydroxy octadecenoic acid (DiHOME) for arachidonic acid (ARA) and linoleic acid (LA), as well as a significant increase of epoxy metabolites of DHA, EPA, ARA and LA in fat-1 transgenic mice treated with a sEH inhibitor.ω-3 epoxy products from ω-3 PUFA metabolism play a crucial role in inhibiting pancreatic cancer growth, and use of ω-3 PUFAs combined with sEH inhibition is a strategy with high potential for pancreatic cancer treatment and prevention.
Systemic lupus erythematosus (SLE) is a systemic autoimmune disease caused by immune dysregulation and characterized by the production of a large number of autoantibodies leading to multiple organ involvement. Despite considerable diagnostic and therapeutic advances in recent decades, SLE remains associated with premature death. However, the exact pathogenesis has not been fully elucidated, and specific treatments are lacking. The development of SLE results from an interaction between genetic and environmental factors. Viral infection is a widely reported environmental trigger of SLE. For example, the Epstein-Barr virus (EBV) is most closely associated with SLE, but the exact mechanisms involved remain unclear. EBV is responsible for two forms of infection: lytic and latent. The lytic phase of infection is mediated by proteins encoded by BZLF1 and BRLF1, which produce a large number of viral particles that express the early antigen (EA), viral capsid antigen (VCA), and membrane antigen (MA). Furthermore, Epstein-Barr nuclear antigen (EBNA) is expressed during latent infection; EBNA1 plays an important role in latency, and EBNA2 is a viral protein essential for B-cell growth transformation.
Objectives:
Systemic lupus erythematosus (SLE)and the Epstein-Barr virus (EBV)are very closely related, but the specific role of EBV in the development of SLE remains unclear.This study estimated the impact of EBV infection status on clinical manifestations and disease remission in patients with SLE.
Methods:
A retrospective study was performed using electronic health records of patients with SLE. The SLE Disease Activity Index (SLEDAI-2K)was used to assess disease activity, with mild activity as SLEDAI-2K ≤ 6, moderate activity as SLEDAI-2K 7 -12, and severe activity as SLEDAI-2K > 12. VCA-IgM-positive or EA-IgM-positive or EBV-DNA copies ≥50 IU/ml were defined as lytic infection group, EBNA-IgG or VCA-IgG-positive and negative for both VCA-IgM and EA-IgM, EBV-DNA copies <50 IU/ml were defined as latent infection group. The end piont was defined as a decrease in SLEDAI-2K score of ≥ one grade from baseline or a decrease in SLEDAI-2K score of ≥4 points from baseline. Cochran Armitage trend test and multivariable logistic regression were further used to analyze the factors influencing EBV proliferation infection.The association of different EBV infection status with treatment response and disease remission in patients with SLE was assessed using propensity score weighting and multivariable Cox regression models.
Results:
The cohort included 217 patients with SLE, 75 in the EBV lytic infection group and 142 in the EBV latent infection group. The SLEDAI-2K score was higher in the proliferative infection group (10.00 (6.25, 16.00) vs. 8.00 (5.00, 10.00), Z=3.96, P<0.001). The proportion of vasculitis (14.7% vs. 2.8%, X2 = 10.71, P = 0.001), serositis (30.7% vs. 13.4%, X2 = 9.40, P = 0.002), and hematological involvement (52.0% vs. 36.6%, X2 = 4.77, P = 0.029) were higher in the lytic infection group than in the latent infection group. A higher proportion of the lytic infection group required methylprednisolone pulse therapy than the latent infection group (17.3% vs. 7.0%, X2=5.49, P=0.019). The results of propensity score-weighted Cox regression implied a statistically significant difference in the effect of EBV lytic infection on disease remission in SLE relative to latent infection (HR 0.30, 95% CI 0.19-0.49, P < 0.001), which was consistent with the results of Cox proportional-hazards regression models analysis (HR 0.16, 95% CI 0.11-0.25, P < 0.001).
Conclusion:
Patients with SLE with lytic EBV infection have higher disease activity than those with latent EBV infection, and those with lytic EBV infection are more likely to have hematologic involvement and manifestations of serositis and vasculitis, and take longer to achieve remission than those with latent infection.
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