Functional metagenomic analysis reveals potential inflammatory triggers associated with genetic risk for autoimmune disease.

To assess functional differences between the microbiomes of individuals with autoimmune risk-associated human leukocyte antigen (HLA) genetics and autoimmune protection-associated HLA, we performed a metagenomic analysis of stool samples from 72 infants in the All Babies in Southeast Sweden general-population cohort and assessed haplotype-peptide binding affinities. Infants with risk-associated HLA DR3-DQ2.5 and DR4-DQ8 had a higher abundance of known pathogen-associated molecular patterns and virulence related genes than infants with protection-associated HLA DR15-DQ6.2. However, there was limited overlap in the type of inflammatory trigger between risk groups. Supported by a high Firmicutes/Bacteroides ratio and differentially abundant flagellated species, genes related to the synthesis of flagella were prominent in those with HLA DR3-DQ2.5. However, this haplotype had a significantly lower likelihood of binding affinity to flagellin peptides. O-antigen biosynthesis genes were significantly correlated with the risk genotypes and absent from protective genotype association, supported by the differential abundance of gram-negative bacteria seen in the risk-associated groups. Genes related to vitamin B biosynthesis stood out in higher abundance in infants with HLA DR3-DQ2.5/DR4-DQ8 heterozygosity compared to those with autoimmune-protective genetics. Prevotella species and genus were significantly abundant in all infant groups with high risk for autoimmune disease. The potential inflammatory triggers associated with genetic risk for autoimmunity have significant implications. These results suggest that certain HLA haplotypes may be creating the opportunity for dysbiosis and subsequent inflammation early in life by clearing beneficial microbes or not clearing proinflammatory microbes. This HLA gatekeeping may prevent genetically at-risk individuals from benefiting from probiotic therapies by restricting the colonization of those beneficial bacteria.

A randomized controlled study of neoadjuvant metformin with chemotherapy in nondiabetic breast cancer women: The METNEO study.

AIMS: Clinical data demonstrate that metformin exhibits antiproliferative, proapoptotic and antimetastatic actions. Here, correlative molecular studies were undertaken to determine the roles of transmembrane tumour necrosis factor-related apoptosis-inducing ligand death receptors (DRs) and CD133, a glycoprotein biomarker of breast cancer (BC) stem cells, in the advantageous action of metformin on pathological and clinical outcomes in BC patients on neoadjuvant chemotherapy. METHODS: We randomly assigned 70 nondiabetic BC patients in a 1:1 ratio to either neoadjuvant AC-T chemotherapy (4 cycles of adriamycin 60 mg/m2 and cyclophosphamide 600 mg/m2, followed by 12 cycles of weekly paclitaxel 80 mg/m2) or AC-T with adjunct metformin (850 mg twice/day). The expressions of DR4, DR5 and CD133 were quantified in excised tissue samples with residual tumour cells. RESULTS: The overall clinical response (odds ratio: 22.67 [2.77-185.18], P = .004), breast-conserving surgery (odds ratio: 3.67 [1.303-10.321], P = .014) and pathological complete response (ß = 2.49 ± 1.13 [0.274-4.712], P = .028) rates were significantly improved in the metformin arm. Tissues obtained from the metformin arm had upregulated mRNA expression of DR4 (Mean delta cycle thresholds ± standard error of the mean: 2.68 ± 0.25 vs. 4.87 ± 0.53, P = .0003) and DR5 (0.21 ± 0.25 vs. 4.29 ± 0.95, P = .0004) compared to control arm. The enhanced DR expression negatively correlated with that of CD133 + BC stem cells, which was significantly reduced by metformin at both cytoplasmic/membranous (43.48 vs. 100.00%, P < .0001) and nuclear sites (4.35 vs. 95.00%, P < .0001). CONCLUSION: Metformin improves clinical and pathological responses to neoadjuvant AC-T chemotherapy in BC via prompting directionally opposite changes in DRs (increments) and CD133 + (decrements) expressions. This study was registered in ClinicalTrials.gov (registration number: NCT04170465, https://clinicaltrials.gov/ct2/show/NCT04170465).

Strophanthidin Induces Apoptosis of Human Lung Adenocarcinoma Cells by Promoting TRAIL-DR5 Signaling.

Strophanthidin (SPTD), one of the cardiac glycosides, is refined from traditional Chinese medicines such as Semen Lepidii and Antiaris toxicaria, and was initially used for the treatment of heart failure disease in clinic. Recently, SPTD has been shown to be a potential anticancer agent, but the underlying mechanism of action is poorly understood. Herein, we explored the molecular mechanism by which SPTD exerts anticancer effects in A549 human lung adenocarcinoma cells by means of mass spectrometry-based quantitative proteomics in combination with bioinformatics analysis. We revealed that SPTD promoted the expression of tumor necrosis factor (TNF)-related apoptosis-inducing ligand receptor 2 (TRAIL-R2, or DR5) in A549 cells to activate caspase 3/6/8, in particular caspase 3. Consequently, the activated caspases elevated the expression level of apoptotic chromatin condensation inducer in the nucleus (ACIN1) and prelamin-A/C (LMNA), ultimately inducing apoptosis via cooperation with the SPTD-induced overexpressed barrier-to-autointegration factor 1 (Banf1). Moreover, the SPTD-induced DEPs interacted with each other to downregulate the p38 MAPK/ERK signaling, contributing to the SPTD inhibition of the growth of A549 cells. Additionally, the downregulation of collagen COL1A5 by SPTD was another anticancer benefit of SPTD through the modulation of the cell microenvironment.

Non-oxidized and oxidized flaxseed orbitides differently induce HepG2 cell apoptosis: involvement of cellular uptake and membrane death receptor DR4.

BACKGROUND: Flaxseed orbitides have health-promoting properties, particularly potent anti-cancer activity. However, flaxseed orbitides containing a methionine structure, such as [1-9-NαC]-linusorb B2 (CLB), are easily oxidized to sulfoxide ([1-9-NαC],[1-Rs,Ss-MetO]-linusorb-B2 (CLC)) and sulfone ([1-9-NαC], [1-MetO]-linusorb B2 (CLK)), with CLC having less anti-cancer ability than CLB. It is unclear why oxidized flaxseed orbitides are less effective against cancer than non-oxidized flaxseed orbitide. RESULTS: Non-oxidized ([1-9-NαC]-linusorb-B3 (CLA) and CLB) and oxidized (CLC and CLK) flaxseed orbitides were found to significantly upregulate the levels of pro-apoptotic proteins, including Bax/Bcl-2, CytoC, caspase-3, and caspase-8, in a dose-dependent manner, with non-oxidized flaxseed orbitides being more effective than oxidized flaxseed orbitides. Mechanically, the cellular absorption of non-oxidized flaxseed orbitides was higher than that of oxidized flaxseed orbitides. Moreover, the significant fluorescence quenching of DR4 protein by flaxseed orbitides (especially non-oxidized orbitides) indicated the formation of a DR4-orbitide complex. Molecular docking demonstrated that non-oxidized orbitides could easily dock into the active cavity of DR4 protein. Further blocking DR4 significantly reduced the ability of non-oxidized flaxseed orbitides to stimulate caspase-3 expression, whereas oxidized flaxseed orbitides retained this ability. CONCLUSION: Non-oxidized flaxseed orbitides are more effective against cancer than oxidized flaxseed orbitides due to higher cellular uptake and activation of the DR4-mediated death receptor signaling pathway. © 2024 Society of Chemical Industry.

PAD2 immunization induces ACPA in wild-type and HLA-DR4 humanized mice.

Rheumatoid arthritis (RA) is associated with HLA-DRB1 alleles expressing the "shared epitope." RA is usually preceded by the emergence of anti-citrullinated protein autoantibodies (ACPAs). ACPAs recognize citrulline residues on numerous proteins. Conversion of arginine into citrulline is performed by enzymes called peptidyl arginine deiminases (PADs). We have previously demonstrated that C3H mice immunized with PADs can produce ACPAs by a hapten-carrier mechanism. Here, we address the influence of HLA-DR alleles in this model in mice expressing RA-associated HLA-DRB1*04:01 (KO/KI*04:01), HLA-DRB1*04:04 (KO/KI*04:04), or non-RA-associated HLA-DRB1*04:02 (KO/KI*04:02) after murine PAD2 immunization. Immunization with mPAD2 triggers production of ACPAs in wild-type (WT) and HLA-DR4 C57BL/6 mice. Both I-Ab and HLA-DR are involved in the activation of mPAD2-specific T lymphocytes. Among HLA-DR4 mice, mice expressing RA-associated HLA-DRB1*04:01 are the best responders to mPAD2 and the best anti-citrullinated peptide antibody producers.

Regulation of anoikis by extrinsic death receptor pathways.

Metastatic cancer cells can develop anoikis resistance in the absence of substrate attachment and survive to fight tumors. Anoikis is mediated by endogenous mitochondria-dependent and exogenous death receptor pathways, and studies have shown that caspase-8-dependent external pathways appear to be more important than the activity of the intrinsic pathways. This paper reviews the regulation of anoikis by external pathways mediated by death receptors. Different death receptors bind to different ligands to activate downstream caspases. The possible mechanisms of Fas-associated death domain (FADD) recruitment by Fas and TNF receptor 1 associated-death domain (TRADD) recruitment by tumor necrosis factor receptor 1 (TNFR1), and DR4- and DR5-associated FADD to induce downstream caspase activation and regulate anoikis were reviewed. This review highlights the possible mechanism of the death receptor pathway mediation of anoikis and provides new insights and research directions for studying tumor metastasis mechanisms. Video Abstract.

Core Fucosylation Mediated by the FucT-8 Enzyme Affects TRAIL-Induced Apoptosis and Sensitivity to Chemotherapy in Human SW480 and SW620 Colorectal Cancer Cells.

Epithelial cells can undergo apoptosis by manipulating the balance between pro-survival and apoptotic signals. In this work, we show that TRAIL-induced apoptosis can be differentially regulated by the expression of α(1,6)fucosyltransferase (FucT-8), the only enzyme in mammals that transfers the α(1,6)fucose residue to the pentasaccharide core of complex N-glycans. Specifically, in the cellular model of colorectal cancer (CRC) progression formed using the human syngeneic lines SW480 and SW620, knockdown of the FucT-8-encoding FUT8 gene significantly enhanced TRAIL-induced apoptosis in SW480 cells. However, FUT8 repression did not affect SW620 cells, which suggests that core fucosylation differentiates TRAIL-sensitive premetastatic SW480 cells from TRAIL-resistant metastatic SW620 cells. In this regard, we provide evidence that phosphorylation of ERK1/2 kinases can dynamically regulate TRAIL-dependent apoptosis and that core fucosylation can control the ERK/MAPK pro-survival pathway in which SW480 and SW620 cells participate. Moreover, the depletion of core fucosylation sensitises primary tumour SW480 cells to the combination of TRAIL and low doses of 5-FU, oxaliplatin, irinotecan, or mitomycin C. In contrast, a combination of TRAIL and oxaliplatin, irinotecan, or bevacizumab reinforces resistance of FUT8-knockdown metastatic SW620 cells to apoptosis. Consequently, FucT-8 could be a plausible target for increasing apoptosis and drug response in early CRC.

TRAIL-Sensitizing Effects of Flavonoids in Cancer.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) represents a promising anticancer agent, as it selectively induces apoptosis in transformed cells without altering the cellular machinery of healthy cells. Unfortunately, the presence of TRAIL resistance mechanisms in a variety of cancer types represents a major hurdle, thus limiting the use of TRAIL as a single agent. Accumulating studies have shown that TRAIL-mediated apoptosis can be facilitated in resistant tumors by combined treatment with antitumor agents, ranging from synthetic molecules to natural products. Among the latter, flavonoids, the most prevalent polyphenols in plants, have shown remarkable competence in improving TRAIL-driven apoptosis in resistant cell lines as well as tumor-bearing mice with minimal side effects. Here, we summarize the molecular mechanisms, such as the upregulation of death receptor (DR)4 and DR5 and downregulation of key anti-apoptotic proteins [e.g., cellular FLICE-inhibitory protein (c-FLIP), X-linked inhibitor of apoptosis protein (XIAP), survivin], underlying the TRAIL-sensitizing properties of different classes of flavonoids (e.g., flavones, flavonols, isoflavones, chalcones, prenylflavonoids). Finally, we discuss limitations, mainly related to bioavailability issues, and future perspectives regarding the clinical use of flavonoids as adjuvant agents in TRAIL-based therapies.

Expression of DR4, DR5, FAS, Caspase-8 and, DDIAS Genes in AML Patients.

Background: Acute myeloid leukemia (AML) is the most common acute leukemia in adults and accompanies a worse survival. In this study, gene expression levels of 5 key players of apoptosis, including DR4, DR5, FAS, caspase 8, and DNA damage-induced apoptosis suppressor (DDIAS), have been evaluated in AML patients compared with controls, aiming to evaluate their possible role and prognostic impact. Methods: This cross-sectional study was performed in the Cancer Molecular Pathology Research Center, Mashhad University of Medical Sciences. A total of 30 newly diagnosed AML cases as well as 30 healthy controls enrolled in the study. Real-time polymerase chain reaction was used to evaluate the expressions of DR4, DR5, FAS, DDIAS, and caspase 8 genes in cases and controls. Other necessary data, including cytogenetic findings, mutations, French-American-British (FAB) classification, and survival, were retrieved from hospital records and by direct contact with patients. Statistical analysis was done by SPSS software. When appropriate, the Mann-Whitney U, Pearson's correlation, and the t tests were utilized. Overall survival (OS) was estimated using the Kaplan-Meier method. Results: The expression of all evaluated genes, including DDIAS (0.89 ± 0.20), DR4 (0.67 ± 0.24), DR5 (0.72 ± 0.24), FAS (0.70 ± 0.25), and Caspase 8 (0.77 ± 0.20) were significantly decreased in AML patients compared with the controls (P < 0.001). Patients with the t (16;16) or inv (16) expressed significantly higher amounts of the FAS gene and those with FLT3 mutation exhibited lower expression of caspase 8. Expression of the evaluated genes showed no significant effect on survival. Conclusion: The expression of DR4, DR5, FAS, and caspase 8 seems to be decreased in AML. Lower expression of these molecules may aid AML cells in avoiding apoptosis because they are involved in the initiation of apoptosis, making them potential targets for treatment.

Vogt-Koyanagi-Harada disease-like uveitis following nivolumab administration treated with steroid pulse therapy: a case report.

BACKGROUND: Immune checkpoint inhibitors can cause various adverse effects. Recently it has been shown that Vogt-Koyanagi-Harada (VKH) disease-like uveitis can occur in patients treated with nivolumab. CASE PRESENTATION: A 69-year-old man developed bilateral panuveitis after nivolumab treatment for recurrent hypopharyngeal cancer. Slit lamp examination revealed bilateral granulomatous keratic precipitates, anterior chamber cells and partial synechiae. Fundus examination revealed bilateral optic disc edema and diffuse serous retinal detachment. His human leukocyte antigen (HLA) typing showed HLA-DRB1*04:05 allele. A lumbar puncture did not demonstrate pleocytosis. Bilateral sub-tenon injections of triamcinolone acetonide were initiated. As his panuveitis did not regress completely, steroid pulse therapy was administered. That therapy led to the resolution of his serous retinal detachment and to rapid improvement in his vision. Following this, we treated him with 50 mg/day of prednisolone for 1 week and then reduced it by 5 mg every week. No bilateral uveitis relapse had occurred by his 3-month follow-up; however, he subsequently died because of his cancer. CONCLUSION: To our knowledge, this is the first report of a patient with NVKH who underwent a lumbar puncture. Unlike VKH, our case did not show meningismus or pleocytosis. NVKH may, therefore, have a different etiology from VKH. In cases of NVKH with posterior uveitis, steroid pulse therapy may be considered as a treatment option, as it is in VKH.

Fucoidan Induces Apoptosis of HT-29 Cells via the Activation of DR4 and Mitochondrial Pathway.

Fucoidan has a variety of pharmacological activities, but the understanding of the mechanism of fucoidan-induced apoptosis of colorectal cancer cells remains limited. The results of the present study demonstrated that the JNK signaling pathway is involved in the activation of apoptosis in colorectal cancer-derived HT-29 cells, and fucoidan induces apoptosis by activation of the DR4 at the transcriptional and protein levels. The survival rate of HT-29 cells was approximately 40% in the presence of 800 µg/mL of fucoidan, but was increased to 70% after DR4 was silenced by siRNA. Additionally, fucoidan has been shown to reduce the mitochondrial membrane potential and destroy the integrity of mitochondrial membrane. In the presence of an inhibitor of cytochrome C inhibitor and DR4 siRNA or the presence of cytochrome C inhibitor only, the cell survival rate was significantly higher than when cells were treated with DR4 siRNA only. These data indicate that both the DR4 and the mitochondrial pathways contribute to fucoidan-induced apoptosis of HT-29 cells, and the extrinsic pathway is upstream of the intrinsic pathway. In conclusion, the current work identified the mechanism of fucoidan-induced apoptosis and provided a novel theoretical basis for the future development of clinical applications of fucoidan as a drug.

The Impact of TRAIL (C1595T and G1525A) and DR4 (rs20576) Gene Polymorphisms on Systemic Lupus Erythematosus.

Apoptosis dysregulation is a distinct hallmark of several disorders like systemic lupus erythematosus (SLE). In fact, SLE has two special features for apoptosis: irregular apoptosis and decline in clearing of apoptotic bodies. Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) is a death ligand that causes to apoptosis via attaching to its receptors such as death receptor-4 (DR4). The present study aimed to evaluate the effects of TRAIL G1525A and C1595T and DR4 A683C (rs20576) gene polymorphisms on SLE development. 160 SLE patients and 160 healthy individuals as the control group participated in the study. Genotype analysis was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). With regard to TRAIL (C1595T) polymorphism, the frequency of CT genotype was significantly higher in the case group than the control with 3-fold increase in SLE development risk (P = 0.0001). Furthermore, the frequency of the TT genotype also was higher in the case group than the control group with 3.2-fold increase in SLE development risk. The allelic distribution analysis defined the T allele as a risk factor for SLE development (P = 0.0001). The frequency of AA genotype and allele A of TRAIL (G1525A) polymorphism also was statistically higher in the case group than the control group (P = 0.0001). There was no significant association between DR4 rs20576 polymorphism and SLE development. TRAIL C1595T and G1525A gene polymorphisms are suggested as the risk factors for SLE development, although the results showed no association between DR4 rs20576 polymorphism and SLE.

Loss of MCL1 function sensitizes the MDA-MB-231 breast cancer cells to rh-TRAIL by increasing DR4 levels.

Triple-negative breast cancer (TNBC) is a form of BC characterized by high aggressiveness and therapy resistance probably determined by cancer stem cells. MCL1 is an antiapoptotic Bcl-2 family member that could limit the efficacy of anticancer agents as recombinant human tumor necrosis factor related apoptosis-inducing ligand (rh-TRAIL). Here, we investigated MCL1 expression in TNBC tissues and cells. We found MCL1 differentially expressed (upregulated or downregulated) in TNBC tissues. Furthermore, in comparison to the human mammary epithelial cells, we found that MDA-MB-231 cells show similar messenger RNA levels but higher MCL1 protein levels, whereas it resulted downregulated in MDA-MB-436 and BT-20 cells. We evaluated the effects of rh-TRAIL and A-1210477, a selective MCL1 inhibitor, on cell viability and growth of MDA-MB-231 cells. We demonstrated that the drug combination reduced the cell growth and activated the apoptotic pathway. Similar effects were observed on three-dimensional cultures and tertiary mammospheres of MDA-MB-231 cells. In MDA-MB-231 cells, after MCL1 silencing, rh-TRAIL confined the cell population in the sub-G0/G1 phase and induced a drop in the mitochondrial transmembrane potential. To understand the molecular mechanism by which the loss of MCL1 function sensitizes the MDA-MB-231 cells to rh-TRAIL, we analyzed by real-time reverse transcription polymerase chain reaction, the expression of genes related to apoptosis, stemness, cell cycle, and those involved in epigenetic regulation. Interestingly, among the upregulated genes through MCL1 silencing or inhibition, there was TNFRSF10A (DR4). Moreover, MCL1 inhibition increased DR4 protein levels and its cell surface expression. Finally, we demonstrated MCL1-DR4 interaction and dissociation of this complex after A-1210477 treatment. Overall, our findings highlight the potential MCL1-roles in MDA-MB-231 cells and suggest that MCL1 targeting could be an effective strategy to overcome TNBC's rh-TRAIL resistance.

Promotion of TRAIL/Apo2L-induced apoptosis by low-dose interferon-ß in human malignant melanoma cells.

Interferon ß (IFN-ß) is considered a signaling molecule with important therapeutic potential in cancer since IFN-ß-induced gene transcription mediates antiproliferation and cell death induction. Whereas, TNF-related apoptosis inducing ligand/Apo2 ligand (TRAIL/Apo2L) has emerged as a promising anticancer agent because it induces apoptosis specifically in cancer cells. In this study, we elucidated that IFN-ß augments TRAIL-induced apoptosis synergistically using five human malignant melanoma cells. All of these cells were induced apoptosis by TRAIL. Whereas, the response against IFN-ß was different in amelanotic cells (A375 and CRL1579) and melanotic cells (G361, SK-MEL-28, and MeWo). The responsibility of amelanotic cells against IFN-ß was higher than those of melanotic cells. The synergism of IFN-ß and TRAIL were correlated with the responsibilities of the cells against IFN-ß. The synergistic interaction was confirmed by a combination index based on the Chou-Talalay method. The upregulation of apoptosis in amelanotic cells was caused by very low doses of IFN-ß (over 0.1 IU/ml). Both of p53-mediated intrinsic pathway and Fas-related extrinsic pathway were activated by IFN-ß alone and combination with TRAIL. Further, TRAIL death receptors (DR4 and DR5) were upregulated by a low-dose IFN-ß (over 0.1 IU/ml) and the expression was more promoted by the combination with TRAIL. It was clarified that the upregulation of DR5 is associated with the declination of viability.

Genetic variations in death receptor domain 4 gene and the susceptibility to hepatitis C related hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide, particularly in Egypt. The role of apoptosis in tumorigenesis has been well-documented and resistance to apoptosis is a hallmark of cancer. Several studies discussed the association between death receptor 4 (DR4) genetic variants and HCC risk. AIM: To study the possible link between DR4 gene polymorphisms and the susceptibility to HCC. METHODS: Genotyping of DR4-C626G, -A683C, and DR4-A1322G single nucleotide polymorphisms (SNP) was determined by polymerase chain reaction assay for 100 de novo HCV-related HCC patients, 100 chronic hepatitis C-related liver cirrhosis patients, and 150 healthy controls. RESULTS: DR4-A1322G polymorphic genotypes (AG and GG) were significantly higher in HCC and cirrhotic patients than controls. The AG genotype conferred two-fold increased risk of HCC (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.56-3.51) and the risk increased to three-fold for the GG genotype (OR, 3.51; 95%CI, 2.33-5.28). The frequency of DR4-C626G and -A683C SNPs in HCC and cirrhotic patients were not significantly different from the controls. Combined genotype analysis showed that coinheritance of the polymorphic genotypes of DR4-C626G and -A1322G conferred nine-fold increased risk of HCC (OR, 9.34; 95%CI, 3.76-23.12). The risk increased to be 12-fold when DR4-A683C and -A1322G variants were coinherited (OR, 11.9; 95%CI, 4.82-29.39). Coexistence of the variant genotypes of the three SNPs conferred almost 10-fold increased risk of HCC (OR, 9.75; 95%CI, 1.86-51.19). CONCLUSIONS: The G allele of DR4 -A1322G could be considered as a novel independent molecular predictor for HCV-related HCC in the Egyptian population.

Synergistic apoptosis of human gastric cancer cells by bortezomib and TRAIL.

Resistance against tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cell death of cancer cells is a major obstacle in clinical application of TRAIL. Variable response to TRAIL of gastric cancer cells, synergy of TRAIL with bortezomib and potential mechanisms behind the phenomena were investigated in this study. The response to TRAIL varied among six gastric cancer cell lines, which correlated with the expression of apoptotic TRAIL receptors. Analysis of TCGA gene expression data showed that DR4 expression correlated with DR5 in gastric cancer. Although higher expression of DR4 was significantly associated with lower T, N and TNM stages, neither DR4 nor DR5 expression meaningfully influenced overall survival rate. Combined treatment of TRAIL with bortezomib resulted in strong synergistic response with enhanced activation of caspases-8, -9 and -3, and increased Annexin V-binding cell fractions in TRAIL-resistant SNU-216 cells. Bortezomib increased the expression of p21cip1/waf1, but p21cip1/waf1 silencing did not restore cell viability significantly. Bortezomib also increased DR5 expression and knockdown of DR5 expression significantly recovered cell viability reduced by the combination treatment. Bortezomib decreased phosphorylation of ERK1/2, but increased that of JNK. Treatment with either an ERK1/2 inhibitor U0126 or a JNK inhibitor SP600125 rescued SNU-216 from dying of bortezomib or combined treatment. However, upregulation of DR5 by bortezomib was knocked down only by inhibition of ERK1/2 activation significantly, but not by JNK activity inhibition. In summary, upregulation of DR5 by bortezomib is of critical significance in the synergy of bortezomib with TRAIL in apoptosis of TRAIL-resistant SNU-216 and that activity of ERK1/2 is required in the bortezomib-induced DR5 overexpression.

Involvement of p38 Activation and Mitochondria in Death of Human Leukemia Cells Induced by an Agonistic Human Monoclonal Antibody Fab Specific to TRAIL Receptor 1.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces cancer cell death with minimal damage to normal cells; however, some cancer cells are resistant to TRAIL. TRAIL resistance may be overcome by agonistic antibodies to TRAIL receptors. In this study, we report the toxic effects of a novel recombinant agonistic human anti-TRAIL receptor 1 (DR4) monoclonal antibody Fab fragment, DR4-4, on various TRAIL-resistant and -sensitive cancer cell lines. The mechanisms of DR4-4 Fab-induced cell death in a human T cell leukemia cell line (Jurkat) were investigated using cell viability testing, immunoblotting, immunoassays, flow cytometry, and morphological observation. DR4-4 Fab-induced caspase-independent necrosis was observed to occur in Jurkat cells in association with p38 mitogen-activated protein kinase activation, cellular FLICE (FADD-like IL-1ß-converting enzyme)-inhibitory protein degradation, decreased mitochondrial membrane potential, and increased mitochondrial reactive oxygen species production. Increased cytotoxic effects of DR4-4 Fab were observed in combination with TRAIL or γ-irradiation. Our results indicate that the novel DR4-4 Fab might overcome TRAIL-resistance and induce death in leukemia cells via cellular mechanisms different from those activated by TRAIL. DR4-4 Fab may have application as a potential therapeutic antibody fragment in single or combination therapy for cancer.

Transcervical Inoculation with Chlamydia trachomatis Induces Infertility in HLA-DR4 Transgenic and Wild-Type Mice.

Chlamydia trachomatis is the leading cause of infection-induced infertility in women. Attempts to control this epidemic with screening programs and antibiotic therapy have failed. Currently, a vaccine to prevent C. trachomatis infections is not available. In order to develop an animal model for evaluating vaccine antigens that can be applied to humans, we used C. trachomatis serovar D (strain UW-3/Cx) to induce infertility in mice whose major histocompatibility complex class II antigen was replaced with the human leukocyte antigen DR4 (HLA-DR4). Transcervical inoculation of medroxyprogesterone-treated HLA-DR4 transgenic mice with 5 × 105C. trachomatis D inclusion forming units (IFU) induced a significant reduction in fertility, with a mean number of embryos/mouse of 4.4 ± 1.3 compared to 7.8 ± 0.5 for the uninfected control mice (P < 0.05). A similar fertility reduction was elicited in the wild-type (WT) C57BL/6 mice (4.3 ± 1.4 embryos/mouse) compared to the levels of the WT controls (9.1 ± 0.4 embryos/mouse) (P < 0.05). Following infection, WT mice mounted more robust humoral and cellular immune responses than HLA-DR4 mice. As determined by vaginal shedding, HLA-DR4 mice were more susceptible to a transcervical C. trachomatis D infection than WT mice. To assess if HLA-DR4 transgenic and WT mice could be protected by vaccination, 104 IFU of C. trachomatis D was delivered intranasally, and mice were challenged transcervically 6 weeks later with 5 × 105 IFU of C. trachomatis D. As determined by severity and length of vaginal shedding, WT C57BL/6 and HLA-DR4 mice were significantly protected by vaccination. The advantages and limitations of the HLA-DR4 transgenic mouse model for evaluating human C. trachomatis vaccine antigens are discussed.

DR4 mediates the progression, invasion, metastasis and survival of colorectal cancer through the Sp1/NF1 switch axis on genomic locus.

The single nucleotide polymorphism (SNP), -397G > T (rs13278062) polymorphism, in the promoter of Death Receptor 4 (DR4) had been reported to be associated with a significantly increased risk for bladder cancer. However, the association of this SNP with the risk of colorectal cancer has not been reported. In this study, we performed a case-control study in 1,078 colorectal cancer patients and 1,175 matched healthy controls to evaluate the association of the potential functional genetic variants in DR4 with risk and survival of colorectal cancer. PCR-TaqMan were used to genotype the rs13278062, rs1000294 and rs2235126 polymorphisms. We found that subjects carrying the rs13278062 GT/TT genotypes had a significantly lower risk and increased survival time when compared to the GG genotype. We also constructed the rs13278062 GT/TT genotype in SW480 and SW620 cells (rs13278062 is GG in both cell lines) with the CRISPR/Cas9 system. Flow cytometry experiments showed that the rs13278062 TT genotype promoted apoptosis in colorectal cancer cells. In vitro and in vivo experiments established that the rs13278062 G to T mutation inhibited carcinogenesis and metastasis of colorectal cancer. Chromatin immunoprecipitation (ChIP) assays revealed that the rs13278062 G > T polymorphism altered the binding affinity of the transcription factors Sp1/NF1 to the rs13278062 mutation region. Immunohistochemistry, western blot, and qPCR corroborated that the rs13278062 GT/TT genotypes increased the expression of DR4 protein in colorectal cancer tissues and cells. In conclusion, these findings indicate that DR4 mediated progression, invasion, metastasis and survival of colorectal cancer via the Sp1/NF1 switch axis on genomics locus.

High Incidence of Celiac Disease in a Long-term Study of Adolescents With Susceptibility Genotypes.

BACKGROUND & AIMS: Little is known about the incidence of celiac disease in the general population of children in the United States. We aimed to estimate the cumulative incidence of celiac disease in adolescents born in the Denver metropolitan area. METHODS: We collected data on HLA-DR, DQ genotypes of 31,766 infants, born from 1993 through 2004 at St. Joseph's Hospital in Denver, from the Diabetes Autoimmunity Study in the Young. Subjects with susceptibility genotypes for celiac disease and type 1 diabetes were followed up for up to 20 years for development of tissue transglutaminase autoantibodies (tTGA). Outcomes were the development of celiac disease autoimmunity (CDA) or celiac disease. CDA was defined as persistence of tTGA for at least 3 months or development of celiac disease. Celiac disease was defined based on detection of Marsh 2 or greater lesions in biopsy specimens or persistent high levels of tTGA. For each genotype, the cumulative incidence of CDA and celiac disease were determined. To estimate the cumulative incidence in the Denver general population, outcomes by each genotype were weighted according to the frequency of each of these genotypes in the general population. RESULTS: Of 1339 subjects followed up, 66 developed CDA and met criteria for celiac disease and 46 developed only CDA. Seropositivity for tTGA resolved spontaneously, without treatment, in 21 of the 46 subjects with only CDA (46%). The estimated cumulative incidence for CDA in the Denver general population at 5, 10, and 15 years of age was 2.4%, 4.3%, and 5.1%, respectively, and incidence values for celiac disease were 1.6%, 2.8%, and 3.1%, respectively. CONCLUSIONS: In a 20-year prospective study of 1339 children with genetic risk factors for celiac disease, we found the cumulative incidence of CDA and celiac disease to be high within the first 10 years. Although more than 5% of children may experience a period of CDA, not all children develop celiac disease or require gluten-free diets.