Targeting Fatty Acid Desaturase I Inhibits Renal Cancer Growth Via ATF3-mediated ER Stress Response

Monounsaturated fatty acids (MUFAs) play a pivotal role in maintaining endoplasmic reticulum (ER) homeostasis, an emerging hallmark of cancer. However, the role of polyunsaturated fatty acid (PUFAs) desaturation in persistent ER stress driven by oncogenic abnormalities remains elusive. Fatty Acid Desaturase 1 (FADS1) is a rate-limiting enzyme controlling the bioproduction of long-chain PUFAs. Our previous research has demonstrated the significant role of FADS1 in cancer survival, especially in kidney cancers. We explored the underlying mechanism in this study. We found that pharmacological inhibition or knockdown of the expression of FADS1 effectively inhibits renal cancer cell proliferation and induces cell cycle arrest. The stable knockdown of FADS1 also significantly inhibits tumor formation in vivo. Mechanistically, we show that while FADS1 inhibition induces ER stress, its expression is also augmented by ER-stress inducers. Notably, FADS1-inhibition sensitized cellular response to ER stress inducers, providing evidence of FADS1's role in modulating the ER stress response in cancer cells. We show that, while FADS1 inhibition-induced ER stress leads to activation of ATF3, ATF3-knockdown rescues the FADS1 inhibition-induced ER stress and cell growth suppression. In addition, FADS1 inhibition results in the impaired biosynthesis of nucleotides and decreases the level of UPD-N-Acetylglucosamine, a critical mediator of the unfolded protein response. Our findings suggest that PUFA desaturation is crucial for rescuing cancer cells from persistent ER stress, supporting FADS1 as a new therapeutic target.

[Application values of right atrial volume, myocardial strain and strain rate in evaluating right atrial function in patients with essential hypertension with normal left ventricular ejection fraction]

Objective: To explore the application values of right atrial (RA) volume, myocardial strain and strain rate in evaluating right atrial functions in patients with essential hypertension (EHT) with normal left ventricular ejection fraction (LVEF). Methods: We retrospectively collected a total of 126 EHT patients with normal LVEF, including 66 males and 60 females, age from 18 to 83(48±15) years from the Affiliated Changzhou No.2 People's Hospital with Nanjing Medical University from March, 2018 to May, 2020. According to the left ventricular mass index, those patients were divided into without left ventricle hypertrophy (LVH) group (n=66) and LVH group (n=60), and 83 healthy volunteers were enrolled as control group, which including 42 males and 41 females, age from 14 to 88 (48±16) years. The total, passive and active RA emptying fraction (total RAEF, passive RAEF and active RAEF) were measured by using RA volumes method. The RA strain (S-reservoir, S-conduit, S-booster pump) and the strain rate (SR-reservoir, SR-conduit, SR-booster pump) were measured by two-dimensional speckle tracking echocardiography. Total RAEF, S-reservoir, and Sr-reservoir represented the reservoir function, while passive RAEF, S-conduit, and Sr-conduit represented the conduit function, and active RAEF, S-booster pump and Sr-booster pump represented the booster pump function, respectively. Than the values between the EHT patients and normal subjects, and the values among the EHT patients without LVH, EHT patients without LVH and normal subjects were compared. Results: The value of active RAEF was significantly lower in EHT patient than normal controls (40.1%±10.5% vs 45.4%±11.1%,P=0.001). There were significant differences among EHT patients without LVH, EHT patients with LVH and normal subjects in passive RAEF and active RAEF (passive RAEF: 40.2%±9.3% vs 36.4%±10.7% vs 36.5%±9.4%, P=0.038, active RAEF: 39.8%±10.6% vs 40.4%±10.4% vs 45.4%±11.1%, P=0.002). There were significant differences in S-reservoir, S-conduit, S-booster pump, SR-reservoir, SR-conduit and SR-booster pump between EHT patients and normal subjects [S-reservoir: 34.8%±13.7% vs 45.0%±13.3%, S-conduit: 18.3%±9.4% vs 26.5%±9.6%, S-booster pump: 16.4%±7.3% vs 18.6%±7.1%, SR-reservoir: (1.6±0.6)/s vs (2.0±0.6)/s, SR-conduit: (-1.2±0.5)/s vs (-1.6±0.6)/s, SR-booster pump: (-1.7±0.6)/s vs (-2.3±0.6)/s; all P<0.05]. The trend tests showed normal controls achieved the largest the absolute values of S-reservoir, S-conduit, SR-reservoir, SR-conduit, SR-booster pump, followed by EHT patients without LVH and EHT patients with LVH(all P<0.001). Conclusions: Using RA volume, myocardial strain and strain rate can detect the RA impaired reservoir, conduit, and the booster pump functions in EHT patients with normal LVEF, and the RA functions were damaged more significantly in EHT patients with LVH.

[Analysis of related factors and prediction of poor ovarian response in patients with controlled ovarian stimulation]

Objective: To explore the related factors of poor ovarian response (POR) in patients receiving controlled ovarian stimulation (COS) and to establish the nomogram for predicting POR in patients who received in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI). Methods: In this retrospective research, clinical data of 17 164 cycles of patients who received IVF/ICSI treatment at Henan Provincial People's Hospital from September 1st, 2016 to September 1st, 2020 were analyzed. Independent correlative factors affecting the occurrence of POR were screened by logistic regression, which were the model enrollment variables in the prediction model. Totally 13 266 cycles with well-record of enrollment variables were screened, and these data were randomly divided into model group (9 896 patients) and validation group (3 370 patients) according to 3∶1. The nomogram was established according to the regression coefficient of the relevant variables. The prediction accuracy of the nomogram was evaluated by calculating area under the receiver operating characteristic curve (AUC). Results: Multivariate logistic regression analysis showed age, infertility type, body mass index, anti-Müllerian hormone, basal follicle stimulating hormone, basal estrogen, antral follicle number, previous times of POR, history of ovarian surgery, ovulation stimulation protocol and average amount of gonadotropin were independent correlative factors affecting the occurrence of POR (all P<0.05). In the model group, according to the above factors, the prediction model and nomogram of POR risk were constructed and the validation group verified the model. The AUC of the model group was 0.893 (95%CI: 0.885-0.900), and the AUC of the validation group was 0.890 (95%CI: 0.878-0.903). Conclusion: The influencing factors of POR after COS in patients treated by IVF/ICSI are screened, and the nomogram for predicting POR established in this study is proved to be effective, simple, intuitive and clear in predicting the occurrence of POR.

Loss of aryl hydrocarbon receptor suppresses the response of colonic epithelial cells to IL22 signaling by upregulating SOCS3

IL22 signaling plays an important role in maintaining gastrointestinal epithelial barrier function, cell proliferation, and protection of intestinal stem cells from genotoxicants. Emerging studies indicate that the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, promotes production of IL22 in gut immune cells. However, it remains to be determined if AhR signaling can also affect the responsiveness of colonic epithelial cells to IL22. Here, we show that IL22 treatment induces the phosphorylation of STAT3, inhibits colonic organoid growth, and promotes colonic cell proliferation in vivo. Notably, intestinal cell-specific AhR knockout (KO) reduces responsiveness to IL22 and compromises DNA damage response after exposure to carcinogen, in part due to the enhancement of suppressor of cytokine signaling 3 (SOCS3) expression. Deletion of SOCS3 increases levels of pSTAT3 in AhR KO organoids, and phenocopies the effects of IL22 treatment on wild-type (WT) organoid growth. In addition, pSTAT3 levels are inversely associated with increased azoxymethane/dextran sulfate sodium (AOM/DSS)-induced colon tumorigenesis in AhR KO mice. These findings indicate that AhR function is required for optimal IL22 signaling in colonic epithelial cells and provide rationale for targeting AhR as a means of reducing colon cancer risk.NEW & NOTEWORTHY AhR is a key transcription factor controlling expression of IL22 in gut immune cells. In this study, we show for the first time that AhR signaling also regulates IL22 response in colonic epithelial cells by modulating SOCS3 expression.

[Influencing factors of thrombosis besides antiphospholipid antibodies in patients with antiphospholipid syndrome]

Objective: To identify the influencing factors of thrombosis besides antiphospholipid antibodies in patients with antiphospholipid syndrome (APS). Methods: The 169 patients diagnosed with APS were enrolled according to the current APS classification criteria from January 2003 to August 2017 in Peking University People's Hospital. There were 23 males and 146 females with a mean age of (41±15) years. Antiphospholipid antibodies, including anticardiolipin (aCL), anti-β2glycoprotein-1 (β2GP1) antibodies and antibodies to the phosphatidylserine-prothrombin complex (aPS/PT), were determined by enzyme-linked immunosorbent assay (ELISA) methods. Lupus anticoagulant (LA) was identified using the STA Compact coagulation testing system. The differences of clinical and laboratory characteristics between patients with and without thrombosis were analyzed (100 cases and 69 cases, respectively). The influencing factors for thrombosis in patients with APS were determined using binary logistic regression. Results: Compared with patients without thrombosis, patients with thrombosis were older and had a longer disease duration ((45±17) years vs (35±9) years and M(Q₁, Q₃) 12.0(3.8, 84.0) months vs 48.0(12.0, 108.0) months, both P<0.05). The percentage of male, primary APS, smoking, low blood platelet count, hypertension, and diabetes in patients with thrombosis were significantly higher than those in patients without thrombosis (all P<0.05). Similarly, the rates of antinuclear antibodies positive, aCL positive, aPS/PT-IgM positive, and aPS/PT-IgG positive in patients with thrombosis were significantly higher than those in patients without thrombosis (all P<0.05). The levels of D-dimer in patients with thrombosis were significantly higher than that in patients without thrombosis (P<0.05). There was significant difference in global anti-phospholipid syndrome score (GAPSS) between patients with and without thrombosis (P<0.05). The GAPSS score was also significantly higher in patients with arterial thrombosis than that in patients with venous thrombosis (P<0.05). Smoking and D-dimer levels were independent influencing factors for thrombosis in patients with APS (smoking: OR=11.222, 95%CI:1.119-112.544, P=0.040, D-dimer levels: OR=1.002, 95%CI: 1.000-1.003, P=0.037). Conclusions: Thrombotic APS patients are older and have a longer suffering duration, a higher ratio of male, primary APS, smoking, hypertension, lower blood platelet count, diabetes, higher GAPSS scale, and higher D-dimer levels. Smoking and D-Dimer levels may be independent risk factors for thrombosis in patients with APS.

Role of the Aryl Hydrocarbon Receptor (AhR) in Mediating the Effects of Coffee in the Colon

SCOPE

This study investigates the mechanism of action and functional effects of coffee extracts in colonic cells, on intestinal stem cell growth, and inhibition of dextran sodium sulfate (DSS)-induced intestinal barrier damage in mice.

METHODS AND RESULTS

Aqueous coffee extracts induced Ah receptor (AhR) -responsive CYP1A1, CYP1B1, and UGT1A1 gene expression in colon-derived Caco2 and YAMC cells. Tissue-specific AhR knockout (AhR^f/f x Lgr5-GFP-CreERT2 x Villin-Cre), wild-type (Lgr5-CreERT2 x Villin-Cre) mice are sources of stem cell enriched organoids and both coffee extracts and norharman, an AhR-active component of these extracts inhibited stem cell growth. Coffee extracts also inhibit DSS-induced damage to intestinal barrier function and DSS-induced mucosal inflammatory genes such as IL-6 and TGF-β1 in wild-type (AhR^+/+ ) but not AhR^-/- mice. In contrast, coffee does not exhibit protective effects in intestinal-specific AhR knockout mice. Coffee extracts also enhanced overall formation of AhR-active microbial metabolites.

CONCLUSIONS

In colon-derived cells and in the mouse intestine, coffee induced several AhR-dependent responses including gene expression, inhibition of intestinal stem cell-enriched organoid growth, and inhibition of DSS-induced intestinal barrier damage. We conclude that the anti-inflammatory effects of coffee in the intestine are due, in part, to activation of AhR signaling.

Assessment of Plasma Membrane Fatty Acid Composition and Fluidity Using Imaging Flow Cytometry

Phospholipid fatty acid (FA) composition influences the biophysical properties of the plasma membrane and plays an important role in cellular signaling. Our previous work has demonstrated that plasma membrane fatty acid composition is an important determinant of oncogenic Ras signaling and that dietary (exogenous) modulation of membrane composition may underlie the chemoprotective benefits of long chain n-3 polyunsaturated fatty acids (PUFA). In this chapter, we describe in vitro methods to modulate membrane phospholipid fatty acid composition of cultured cells using fatty acids complexed to bovine serum albumin (BSA). Furthermore, we describe a method to quantify the biophysical properties of plasma membranes in live cells using Di-4-ANEPPDHQ (Di4) and image-based flow cytometry.

[Analysis of the level of T lymphocyte subsets and the relationship with the prognosis of pulmonary fibrosis in patients with paraquat poisoning]

Objective: To analyze the levels of T lymphocyte subsets (CD3, CD4, CD8 and CD4/CD8) in patients with paraquat poisoning, and to explore the relationship between the changes of T lymphocyte subsets and the prognosis of pulmonary fibrosis. Methods: In October 2019, a total of 47 patients with oral 20% paraquat low water solvent poisoning in Guangzhou 12th people's Hospital from June 2018 to June 2019 were selected as the research objects. Patients were divided into early death group (16 cases died within 2 weeks) and non early death group (31 cases survived more than 2 weeks) . The non early death group was divided into pulmonary fibrosis group (23 cases) and normal lung group (8 cases) . 20 healthy people in the same period were randomly selected as the control group. The neutrophils (N) , C reaction protein (CRP) , alanine aminotransferase (ALT) , creatinine (Cr) , amylase (aAMY) , creatine kinase isoenzyme (CKMB) , pH, HCO(3)(-), blood oxygen saturation (SO(2)) and lactic acid (Lac) of patients poisoned within 3 d were examined every day. Independent sample t-test was used for inter group comparison, and paired sample t-test was used for intra group comparison. Results: Compared with non early death group, the levels of N, CRP, ALT, Cr, aAMY, CKMB and Lac in early death group increased (P<0.05) , while pH and HCO(3)(-) decreased (P<0.05) . Compared with the control group, the levels of CD3, CD4 and CD4/CD8 were decreased on the first day in the early death group and non early death group (P<0.05) , and the levels of CD3, CD4 and CD4/CD8 were decreased on the 15th day in the pulmonary fibrosis group (P<0.05) . Compared with the normal lung group, the levels of CD3, CD4 and CD4/CD8 in the pulmonary fibrosis group decreased on the 15th day (P<0.05) . Conclusion: The persistent low cellular immune function in patients with paraquat poisoning is related to the progress of pulmonary fibrosis, which is an important factor affecting the prognosis of patients with pulmonary fibrosis.

Fatty Acid Desaturase 1 Influences Hepatic Lipid Homeostasis by Modulating the PPARα-FGF21 Axis

The fatty acid desaturase 1 (FADS1), also known as delta-5 desaturase (D5D), is one of the rate-limiting enzymes involved in the desaturation and elongation cascade of polyunsaturated fatty acids (PUFAs) to generate long-chain PUFAs (LC-PUFAs). Reduced function of D5D and decreased hepatic FADS1 expression, as well as low levels of LC-PUFAs, were associated with nonalcoholic fatty liver disease. However, the causal role of D5D in hepatic lipid homeostasis remains unclear. In this study, we hypothesized that down-regulation of FADS1 increases susceptibility to hepatic lipid accumulation. We used in vitro and in vivo models to test this hypothesis and to delineate the molecular mechanisms mediating the effect of reduced FADS1 function. Our study demonstrated that FADS1 knockdown significantly reduced cellular levels of LC-PUFAs and increased lipid accumulation and lipid droplet formation in HepG2 cells. The lipid accumulation was associated with significant alterations in multiple pathways involved in lipid homeostasis, especially fatty acid oxidation. These effects were demonstrated to be mediated by the reduced function of the peroxisome proliferator-activated receptor alpha (PPARα)-fibroblast growth factor 21 (FGF21) axis, which can be reversed by treatment with docosahexaenoic acid, PPARα agonist, or FGF21. In vivo, FADS1-knockout mice fed with high-fat diet developed increased hepatic steatosis as compared with their wild-type littermates. Molecular analyses of the mouse liver tissue largely corroborated the observations in vitro, especially along with reduced protein expression of PPARα and FGF21. Conclusion: Collectively, these results suggest that dysregulation in FADS1 alters liver lipid homeostasis in the liver by down-regulating the PPARα-FGF21 signaling axis.

[Detection of neuron-specific enolase in patients with subacute 1, 2-dichloroethane poisoning]

Objective: To investigate the changes of neuron-specific enolase (NSE) in serum and cerebrospinal fluid of patients with subacute 1, 2-dichloroethane (DCE) poisoning. Methods: Ten patients with subacute 1, 2-DCE poisoning hospitalized in Guangzhou 12th Municipal People's Hospital from December 2014 to March 2019 were taken as the subacute 1, 2-DCE poisoning group, 34 typical acute toxic encephalopathy patients hospitalized at the same time as typical acute toxic encephalopathy group, 40 healthy physical examinees as normal control group. The levels of serum NSE in patients of subacute 1, 2-DCE poisoning and typical acute toxic encephalopathy group during onset and improvement were detected by chemiluminescence method, and the results were analyzed statistically. The level of NSE in cerebrospinal fluid of subacute 1, 2-DCE poisoning group was detected and analyzed its correlation with the level of NSE in serum. Using receiver operator characteristic (ROC) curve to analyze the diagnostic efficacy of NSE in subacute 1, 2-DCE poisoning and typical acute toxic encephalopathy (area under curve, AUC) . Results: There was no significant difference between the serum NSE level of the patients with subacute 1, 2-DCE poisoning in the onset group and the normal control group and the improvement group (P>0.05) . The serum NSE level of subacute 1, 2-DCE poisoning in the improvement group was lower than those in the normal control group (P<0.01) . The serum NSE level of the subacute 1, 2-DCE poisoning in the onset group was lower than those in the typical acute toxic encephalopathy in the onset group (P<0.01) . There was no linear correlation between cerebrospinal fluid NSE and serum NSE in patients with subacute 1, 2-DCE poisoning (r=-0.183, P=0.52) . ROC curve showed that the AUC of serum NSE in diagnosing subacute 1, 2-DCE poisoning and typical acute toxic encephalopathy were 0.661 and 0.726, respectively. Conclusion: There is no significant change in serum NSE in patients with subacute 1, 2-DCE poisoning.

Function of IL-33 in Wound Age Estimation of Skin Wounds in Mice

Abstract

Objective To explore the application value of interleukin-33 （IL-33） in wound age estimation in forensic practice by observing the sequential changes of IL-33 after skin wound. Methods Skin wound models were generated on the back of mice with a round file of 5 mm in diameter. Skin samples of the same size were taken from the same parts of mice in control group and injury group 1 h, 3 h, 6 h, 12 h, 1 d, 3 d, 5 d, 7 d and 10 d after skin wound. Hematoxylin-eosin （HE） staining method was applied to observe the morphological changes in the recovering process after skin wound. Western blotting, immunohistochemistry staining and double immunofluorescence staining methods were applied to detect the expression changes of IL-33 in the skin wound samples. Results The results of Western blotting showed that the expression of IL-33 protein decreased slightly at 3 h after skin wound, increased gradually at 6 h after skin wound, and reached the peak value at 3 d, then decreased gradually. Immunohistochemistry staining results showed that faint positive expression of IL-33 was observed in epidermis, hair follicles, sebaceous glands and dermal resident cells of the control group skin. The positive cell rate of IL-33 increased at 3 h after skin wound and reached the peak value at 3 d, then decreased gradually. The results of double immunofluorescence staining showed that the majority of IL-33 positive cells from 1 d to 3 d after wound were macrophages, while the majority of IL-33 positive cells from 5 d to 7 d after wound were myofibroblasts. In addition, the results of HE staining showed that the wound healing process of the skin wound model was consistent with the pathological development law of inflammation. Conclusion IL-33 could become a reference index for wound age estimation of skin wound in forensic practice.

Effects of laying breeder hens dietary β-carotene, curcumin, allicin, and sodium butyrate supplementation on the jejunal microbiota and immune response of their offspring chicks

Our long-term goal is to improve chick health and reduce the use of antibiotics in the poultry industry via maternal effects. To link jejunal microbes with chicks' different immune levels and growth performance in our previous research, this study investigated jejunal microbes, jejunal inflammation, and immune responses based on a comparison between different groups. Newly hatched Hy-Line chicks were allotted into 3 groups: a chick control group (cCON), a ciprofloxacin lactate treatment group (Cipro)—the chicks of the cCON and Cipro groups were hatched from laying breeder hens given a basal diet—and a 5-wk β-carotene, curcumin, allicin, and sodium butyrate supplementation group (cCCAB), wherein chicks hatched from laying breeder hens. All groups were fed the same diet for 4 wk; the Cipro group was given ciprofloxacin lactate in drinking water continuously. At the end of the experiment, the results demonstrated that the jejunal microbes of the Cipro group showed significant changes in alpha and beta diversity, and in taxonomy at phylum and genus levels. Statistically, a total of 67 significantly enriched (P < 0.05) taxa were identified between groups by linear discriminant analysis effect size; Firmicutes was significantly enriched (P < 0.05) in the cCCAB group, 65 taxa were significantly enriched (P < 0.05) in the Cipro group, and 32 of the 65 enriched (P < 0.05) taxa were in the Proteobacteria phylum of the Cipro group. Levels of lipopolysaccharide in jejunal content, and nuclear factor kappa-B, and tumor necrosis factor-α in jejunums of the Cipro and cCCAB groups were increased (all P < 0.05) compared to those in the cCON group. There was obvious neutrophil infiltration and upregulated (all P < 0.05) IL-6 mRNA in the Cipro group jejunums compared to the cCON and cCCAB groups. The expression of PSME3 and PSME4 genes was upregulated (all P < 0.05) in the cCCAB group compared to the cCON and Cipro groups. In conclusion, ciprofloxacin lactate administration led to potential hazards in health and growth in chicks via microbial disturbances-induced jejunal inflammation, and laying breeder hens dietary supplementation with β-carotene, curcumin, allicin, and sodium butyrate could enhance jejunal immunity of their offspring via the interaction between host innate immunity selected microbial colonization and microbiota educated adaptive immunity.

Application of Virtual Anatomy Technology in Postmortem Examination of Medical Dispute Cases

Abstract

Objective To discuss the application value of CT scanning technology in cause of death determination of medical dispute cases. Methods From July 2017 to December 2018, postmortem CT imaging data of 12 medical dispute cases were collected. CT imaging diagnosis results and anatomy findings as well as differences between antemortem and postmortem CT diagnosis were compared. The advantages and disadvantages of CT routine tests of the cadavers in terms of the diagnosis of disease and damage were analyzed. Results The comparison between CT imaging diagnosis and anatomical findings showed that CT scans had advantages in the diagnosis of disease and damage with large differences in density changes, such as atelectasis, pneumonia, calcification, fracture and hemorrhage, etc. The comparison of CT diagnosis in antemortem and postmortem examination showed that the cadavers of medical dispute cases were well preserved and that postmortem CT scan was meaningful for the diagnosis of antemortem diseases. Conclusion Virtual anatomy technology has a relatively high application value in postmortem examination of medical dispute cases. It can provide effective information for the appraisers before the autopsy and can also provide a reference for cause of death analysis when the anatomy cannot be performed.

Lipidomic and biophysical homeostasis of mammalian membranes counteracts dietary lipid perturbations to maintain cellular fitness

Proper membrane physiology requires maintenance of biophysical properties, which must be buffered from external perturbations. While homeostatic adaptation of membrane fluidity to temperature variation is a ubiquitous feature of ectothermic organisms, such responsive membrane adaptation to external inputs has not been directly observed in mammals. Here, we report that challenging mammalian membranes by dietary lipids leads to robust lipidomic remodeling to preserve membrane physical properties. Specifically, exogenous polyunsaturated fatty acids are rapidly incorporated into membrane lipids, inducing a reduction in membrane packing. These effects are rapidly compensated both in culture and in vivo by lipidome-wide remodeling, most notably upregulation of saturated lipids and cholesterol, resulting in recovery of membrane packing and permeability. Abrogation of this response results in cytotoxicity when membrane homeostasis is challenged by dietary lipids. These results reveal an essential mammalian mechanism for membrane homeostasis wherein lipidome remodeling in response to dietary lipid inputs preserves functional membrane phenotypes.

Proper membrane physiology requires maintenance of a narrow range of physicochemical properties, which must be buffered from external perturbations. Here, authors report lipidomic remodeling to preserve membrane physical properties upon exogenous polyunsaturated fatty acids exposure.

Cross-talk between SIM2s and NFκB regulates cyclooxygenase 2 expression in breast cancer

Background

Breast cancer is a leading cause of cancer-related death for women in the USA. Thus, there is an increasing need to investigate novel prognostic markers and therapeutic methods. Inflammation raises challenges in treating and preventing the spread of breast cancer. Specifically, the nuclear factor kappa b (NFκB) pathway contributes to cancer progression by stimulating proliferation and preventing apoptosis. One target gene of this pathway is PTGS2, which encodes for cyclooxygenase 2 (COX-2) and is upregulated in 40% of human breast carcinomas. COX-2 is an enzyme involved in the production of prostaglandins, which mediate inflammation. Here, we investigate the effect of Singleminded-2s (SIM2s), a transcriptional tumor suppressor that is implicated in inhibition of tumor growth and metastasis, in regulating NFκB signaling and COX-2.

Methods

For in vitro experiments, reporter luciferase assays were utilized in MCF7 cells to investigate promoter activity of NFκB and SIM2. Real-time PCR, immunoblotting, immunohistochemistry, and chromatin immunoprecipitation assays were performed in SUM159 and MCF7 cells. For in vivo experiments, MCF10DCIS.COM cells stably expressing SIM2s-FLAG or shPTGS2 were injected into SCID mice and subsequent tumors harvested for immunostaining and analysis.

Results

Our results reveal that SIM2 attenuates the activation of NFκB as measured using NFκB-luciferase reporter assay. Furthermore, immunostaining of lysates from breast cancer cells overexpressing SIM2s showed reduction in various NFκB signaling proteins, as well as pAkt, whereas knockdown of SIM2 revealed increases in NFκB signaling proteins and pAkt. Additionally, we show that NFκB signaling can act in a reciprocal manner to decrease expression of SIM2s. Likewise, suppressing NFκB translocation in DCIS.COM cells increased SIM2s expression. We also found that NFκB/p65 represses SIM2 in a dose-dependent manner, and when NFκB is suppressed, the effect on the SIM2 is negated. Additionally, our ChIP analysis confirms that NFκB/p65 binds directly to SIM2 promoter site and that the NFκB sites in the SIM2 promoter are required for NFκB-mediated suppression of SIM2s. Finally, overexpression of SIM2s decreases PTGS2 in vitro, and COX-2 staining in vivo while decreasing PTGS2 and/or COX-2 activity results in re-expression of SIM2.

Conclusion

Our findings identify a novel role for SIM2s in NFκB signaling and COX-2 expression.

[Study on purification effect of formaldehyde in cleanroom by new return air device]

Objective: To effectively reduce the concentration of poisons in cleanroom, protect the health of workers, realize the optimization and automatic control of the new return air device. And the influence of initial concentration, air volume, temperature and relative humidity of formaldehyde on the purification effect of the new return air device was explored. Methods: The purification effect of the new return air device installed with the activated carbon and the photocatalyst purification net or ordinary activated carbon purification network was tested in a 60 m(3) simulated cleanroom. The concentration of formaldehyde was determined by solution absorption-phenol reagent spectrophotometry. Based on the single factor experiment to determine the combination of two purification nets. The effects of air volume, initial formaldehyde concentration, temperature and relative humidity on the purification effect of the new return air device were investigated by orthogonal test. Then, the performance parameters of the return air device to purify formaldehyde were determined. Results: The formaldehyde purification efficiency of the two types of purification nets in the new return air device was higher than that of the ordinary activated carbon purification network (P<0.05) . The combination of activated carbon and photocatalyst purification net has no effect on the formaldehyde purification efficiency of the return air device (P>0.05) . According to the direct analysis and variance analysis, air volume was the most sensitive factor (F value is 18.894, P<0.05) , followed by initial concentration (F value is 16.128, P<0.05) , while temperature and relative humidity have little effect (F value is 0.041 and 0.599, respectively, P>0.05) . LSD analysis showed that there was no significant difference in the purification efficiency of formaldehyde between 475 m(3)/h and 626 m(3)/h (P>0.05) . From the perspective of formaldehyde purification efficiency and energy saving, when the air volume is set to 475 m(3)/h, the new return air device has higher purification efficiency for high concentration of formaldehyde. Conclusion: The new return air device consisting of activated carbon and photocatalyst purification net can play a good purification role in cleanroom with different temperatures and different humidity. Its formaldehyde purification efficiency is affected by air volume and initial concentration.

[Correlation between prognosis and laboratory parameters of complete deafness in patients with sudden deafness]

Objective: To study the correlation between the prognosis of sudden deafness and laboratory indicators, and to provide a theoretical basis for clinical evaluation of prognosis and selection of appropriate interventions.Method: A retrospective analysis of 123 cases of total deafness was conducted(all frequencies decreased with 250-8 000 Hz average hearing threshold ≥ 81 dB HL). All patients admitted to the hospital received laboratory test within 24 hours and underwent a unified treatment: alprostadil + mecobalamin + citicoline sodium phosphate + Ginkgo biloba extract + batroxobin + methylprednisolone (patients with hypertension or diabetes were given retro-auricular injection). After 2 weeks of comprehensive treatment, the pure tone audiometry was reviewed and the clinical efficacy was evaluated. According to the prognosis, the patients were divided into the healing group, the marked effective group, the effective group and the ineffective group. The laboratory indicators included: white blood cell count, neutrophil percentage, neutrophil lymphocyte ratio(NHR), erythrocyte sedimentation rate, blood lipid, red blood cell count, hemoglobin(Hb), plasma fibrinogen content(FIB). Result: There were no significant differences in white blood cell count, neutrophil percentage, NHR, erythrocyte sedimentation rate, blood lipid index and red blood cell count between different prognosis groups(all P>0.05). The differences of FIB and Hb were statistically significant(P<0.05). The overall prognosis was negatively correlated with FIB and positively correlated with Hb. Patients with vertigo had a worse prognosis and a higher plasma FIB level than those without vertigo(P<0.05), but there was no significant difference of Hb between patients with and without vertigo(P>0.05). Conclusion: FIB and Hb can be used as correlative indexes to evaluate the prognosis of patients with sudden deafness, and the effects of vertigo and other associated symptoms on the prognosis should be comprehensively analyzed. .

Time-dependent Expression and Distribution of AChE during the Skin Incised Wound Healing in Mice

Abstract

Objective To study the time-dependent expression and distribution of acetylcholinesterase （AChE） during skin incised wound healing in mice, and discuss its effect in wound healing as well as the feasibility of using it as a reference index for wound age estimation. Methods A total of 45 C57BL/KsJ mice were randomly divided into one control group and eight incised groups. The skin incised wound model was established in the incised groups with samples of skin wounds taken at 6 h, 12 h, 1 d, 3 d, 5 d, 7 d, 10 d and 14 d post-injury respectively, while the uninjured skin tissue was extracted in the control group. Expression and distribution of AChE in skin samples were detected by immunohistochemistry, double immunofluorescence and Western blotting. Results Immunohistochemistry results indicated that AChE was mainly detected in infiltrating polymorphonuclear cells （PMNs） 6 to 12 h post-injury. A large number of AChE-positive mononuclear cells （MNCs） were observed 1 to 3 d post-injury. The AChE-positive cells were mainly fibroblastic cells （FBCs） 5 to 14 d post-injury. The ratio of the AChE-positive cells increased initially 6 h post-injury, and reached the peak at 1 d post-injury. Double immunofluorescent staining showed that the majority of AChE-positive MNCs and FBCs expressed macrophage marker and myofibroblast marker, respectively. Western blotting results showed that the relative expression level of AChE in the incised group was higher than that in the control group averagely, reached the peak at 1 d post-injury, then reached a second peak at 7 d post-injury. Conclusion The expression of AChE is found in PMNs, macrophages and myofibroblast during skin wound healing, which indicates it might be involved in the adjustment of inflammatory response and fibrotic repair after injury. Moreover, combined use of various methods for the detection of the expression of AChE would provide reference for skin wound age estimation.

Relationship between the Number of Neutrophils and Myofibroblasts during Diabetic Wound Healing and Wound Age

Abstract

Objective To investigate the sequential changes of the number of neutrophils and myofibroblasts during diabetic wound healing, and discuss its application value in wound age estimation. Methods Diabetic DB mice and mice of the same age in the normal control group were selected, a wound healing model was established, wound samples were taken at different time points, while the number of neutrophils and myofibroblasts during diabetic wound healing were determined by immunohistochemical staining technique. Results The number of infiltrated neutrophils in the wounds of control and diabetic groups reached the peak respectively at 12 h and 5 d after injury. Compared with the control group, the number of neutrophils in the diabetic group decreased significantly from 6 h to 1 d after injury, but increased markedly from 5 d to 14 d. From 5 d to 10 d after injury, the average number of neutrophils at high magnification in wounds of the diabetic group was over 30, while that of neutrophils in wounds of the control group was less than 20. Myofibroblasts appeared in wounds from 3 d to 14 d after injury in the control group and from 5 d to 14 d after injury in the diabetic group. The difference in the number of myofibroblasts in wounds between control group and diabetic group from 3 to 7 d after injury had statistical significance. Conclusion In comparison with normal wound healing, the number of neutrophils and myofibroblasts during diabetic wound healing shows different sequential changes. The results of this study can provide reference for wound age estimation of patients with severe diabetes.

[Curative effect analysis of bile reinfusion combined with enteral nutrition support before surgery of hilar cholangiocarcinoma]

Objective: To investigate the clinical effect of bile reinfusion combined with enteral nutrition support before surgery for hilar cholangiocarcinoma. Methods: A retrospective analysis of patients with hilar cholangiocarcinoma who underwent surgical treatment at Nanjing Drum Tower Hospital Hepato-biliary-pancreatic Surgery Department from July 2010 to August 2017 was completed.A total of 52 cases were finally enrolled in our study.All the patients included, on the basis of whether they received preoperative drainage and bile reinfusion, were divided into non-drainage group(n=15) and drainage group(n=37). Differences of clinical indicators, including operation time, intraoperative bleeding and serum liver function index levels at day 1, 3, 7 postoperative, postoperative complications(liver failure, biliary fistula, pleural effusion, peritoneal effusion, abdominal cavity infection, death in hospital), tumor classification, R0 resection, postoperative hospitalization time between the 2 groups were analyzed. At the same time, in the drainage group, patients were divided into non-enteral nutrition subgroup(n=13) and enteral nutrition subgroup(n=24) according to whether they received enteral nutrition before operation. The normal distribution data of the group was statistically analyzed by independent sample t test, the non-normal distribution data of the group was statistically analyzed by rank-sum test. The count data was statistically analyzed by non-calibration and correction of the square test. Results: There was no statistically significant difference in general infomation such as age, gender, and serum liver function between non-drainage group and drainage group(P>0.05). There was no statistically significant difference in general information such as age, gender, and serum liver function between non-enteral nutrition group and enteral nutrition group(P>0.05). The rate of vascular resection and reconstruction(33.3%) and operating time(10.8(2.2)h) in drainage group were both higher than those in non-drainage group(6.7% and 8.3(3.0)h), the differences were both statistically significant(χ(2)=4.397, Z=1.595; both P<0.05). The level of AST at the 7th day after surgery in drainage group(32.8(17.3)U/L) was significantly lower than that in non-drainage group(55.0(64.7)U/L), the difference was statistically significant(Z=-2.212, P<0.05). The level of TBil at 1st day after surgery in drainage group(43.6(91.2)μmol/L) was lower than that in non-drainage group(91.2(188.4)μmol/L), the difference was statistically significant(Z=-2.150, P<0.05). The rate of pancreatoduodenectomy(25.0%) and average operating time(11.1(1.3)h) in the enteral nutrition group were both higher than those in the non-enteral nutrition group(0, 9.0(2.6)h). The differences were both statistically significant(χ(2)=3.879, Z=-2.693; P<0.05). The average level of AST at the 1st day after surgery in enteral nutrition group(396.4(268.3)U/L) was significantly lower than that in non-enteral nutrition group(642.5(341.1)U/L), the difference was statistically significant(Z=-2.483, P<0.05). The average level of TBil at the 1st, 3th day after surgery in enteral nutrition group(38.8(21.5)μmol/L and 30.0(25.6)μmol/L) were both lower than those in non-enteral nutrition group(60.9(75.2)μmol/L and 46.5(50.0)μmol/L), the differences were both statistically significant(Z=-2.416, -2.026; P<0.05). The level of CRP at 1st, 3th day after surgery((41.9±31.1)mg/L, (50.8±31.4)mg/L)in enteral nutrition subgroup was lower than that in non-enteral nutrition subgroup((64.4±33.6)mg/L, (74.1±35.3)mg/L), the differences were both statistically significant(t=1.456, 1.675; P<0.05). Conclusion: Based on the present study , there is no effective improvement on postoperative recovery using bile reinfusion combined with nutrition support before R0 resection of hilar cholangiocarcinoma.

Expression of Annexin A1 during Skin Incised Wound Healing in Mice

OBJECTIVES

To investigate the expression changes of annexin A1 （ANXA1） during the process of skin incision healing, and to explore its expression and function during skin injury repair.

METHODS

The skin injury model of mice was prepared, and skin tissues of the controls and the injured group at 6 h, 12 h, 1 d, 3 d, 5 d, 7 d, 10 d and 14 d after injuries were taken. The morphological changes of the wound were observed by hematoxylin-eosin （HE） staining, and the expression of ANXA1 was detected by immunohistochemistry （IHC） and Western blotting.

RESULTS

HE staining showed normal healing of skin wounds. IHC results revealed that ANXA1 was expressed in the epidermis, hair follicle, sebaceous gland and vascular endothelium. In the injured group, the expression of ANXA1 was enhanced in epidermis and skin appendages around the wound 6-12 h after injury, and ANXA1 was also highly expressed in neutrophils and a small number of mononuclear cells. ANXA1 was mainly positively expressed in monocytes, neovascular endothelial cells and fibroblasts, and small amount of fibroblasts at 1-3 d, 5-10 d, and 14 d after injury, respectively. Western blotting showed that, compared with the controls, the expression of ANXA1 was significantly increased at 6 h after injury, peaked at 1 d, and then decreased gradually in the injured group.

CONCLUSIONS

ANXA1 may be involved in the regulation of skin damage repair, with time-dependent expression during skin wound healing, and thus is expected to be a biological marker for inferring the wound formation time.

Murine Colonic Organoid Culture System and Downstream Assay Applications

Colonic organoids, three-dimensional colonic crypts grown in vitro that show realistic microanatomy, have many potential applications for studying physiology, developmental biology, and pathophysiology of intestinal diseases including inflammatory bowel disease and colorectal cancer. Here, we describe detailed protocols for mouse colonic crypt isolation, organoid culture, and downstream applications. Specific culture strategies including growth factor enriched Matrigel and Wnt and R-spondin conditioned media serve as key factors for enhancing the growth and cost efficiency of colonic organoid cultures.

Eicosapentaenoic acid in combination with EPHA2 inhibition shows efficacy in preclinical models of triple-negative breast cancer by disrupting cellular cholesterol efflux

Triple-negative breast cancer (TNBC), the most aggressive breast cancer subtype, currently lacks effective targeted therapy options. Eicosapentaenoic acid (EPA), an omega-3 fatty acid and constituent of fish oil, is a common supplement with anti-inflammatory properties. Although it is not a mainstream treatment, several preclinical studies have demonstrated that EPA exerts anti-tumor activity in breast cancer. However, against solid tumors, EPA as a monotherapy is clinically ineffective; thus, we sought to develop a novel targeted drug combination to bolster its therapeutic action against TNBC. Using a high-throughput functional siRNA screen, we identified Ephrin type-A receptor 2 (EPHA2), an oncogenic cell-surface receptor tyrosine kinase, as a therapeutic target that sensitizes TNBC cells to EPA. EPHA2 expression was uniquely elevated in TNBC cell lines and patient tumors. In independent functional expression studies in TNBC models, EPHA2 gene-silencing combined with EPA significantly reduced cell growth and enhanced apoptosis compared with monotherapies, both in vitro and in vivo. EPHA2 specific inhibitors similarly enhanced the therapeutic action of EPA. Finally, we identified that therapy-mediated apoptosis was attributed to a lethal increase in cancer cell membrane polarity due to ABCA1 inhibition and subsequent dysregulation of cholesterol homeostasis. This study provides new molecular and pre-clinical evidence to support a clinical evaluation of EPA combined with EPHA2 inhibition in patients with TNBC.

Long-Chain n-3 Fatty Acids Attenuate Oncogenic KRas-Driven Proliferation by Altering Plasma Membrane Nanoscale Proteolipid Composition

Ras signaling originates from transient nanoscale compartmentalized regions of the plasma membrane composed of specific proteins and lipids. The highly specific lipid composition of these nanodomains, termed nanoclusters, facilitates effector recruitment and therefore influences signal transduction. This suggests that Ras nanocluster proteolipid composition could represent a novel target for future chemoprevention interventions. There is evidence that consumption of fish oil containing long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) such as eicosapentaenoic acid (EPA, 20:5^{Δ5,8,11,14,17}) and docosahexaenoic acid (DHA, 22:6^{Δ4,7,10,13,16,19}) may reduce colon cancer risk in humans, yet the mechanism underlying this effect is unknown. Here, we demonstrate that dietary n-3 PUFA reduce the lateral segregation of cholesterol-dependent and -independent nanoclusters, suppressing phosphatidic acid-dependent oncogenic KRas effector interactions, via their physical incorporation into plasma membrane phospholipids. This results in attenuation of oncogenic Ras-driven colonic hyperproliferation in both Drosophila and murine models. These findings demonstrate the unique properties of dietary n-3 PUFA in the shaping of Ras nanoscale proteolipid complexes and support the emerging role of plasma membrane-targeted therapies.Significance: The influence of dietary long chain n-3 polyunsaturated fatty acids on plasma membrane protein nanoscale organization and KRas signaling supports development of plasma membrane-targeted therapies in colon cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/14/3899/F1.large.jpg Cancer Res; 78(14); 3899-912. ©2018 AACR.

Omega-3 fatty acids, membrane remodeling and cancer prevention

Proteins are often credited as the macromolecule responsible for performing critical cellular functions, however lipids have recently garnered more attention as our understanding of their role in cell function and human health becomes more apparent. Although cellular membranes are the lipid environment in which many proteins function, it is now apparent that protein and lipid assemblies can be organized to form distinct micro- or nanodomains that facilitate signaling events. Indeed, it is now appreciated that cellular function is partly regulated by the specific spatiotemporal lipid composition of the membrane, down to the nanosecond and nanometer scale. Furthermore, membrane composition is altered during human disease processes such as cancer and obesity. For example, an increased rate of lipid/cholesterol synthesis in cancerous tissues has long been recognized as an important aspect of the rewired metabolism of transformed cells. However, the contribution of lipids/cholesterol to cellular function in disease models is not yet fully understood. Furthermore, an important consideration in regard to human health is that diet is a major modulator of cell membrane composition. This can occur directly through incorporation of membrane substrates, such as fatty acids, e.g., n-3 polyunsaturated fatty acids (n-3 PUFA) and cholesterol. In this review, we describe scenarios in which changes in membrane composition impact human health. Particular focus is placed on the importance of intrinsic lipid/cholesterol biosynthesis and metabolism and extrinsic dietary modification in cancer and its effect on plasma membrane properties.

[Relationship between FoxO1 Expression and Wound Age during Skin Incised Wound Healing]

OBJECTIVES

To investigate FoxO1 expression and its time-dependent changes during the skin incised wound healing.

METHODS

After the establishment of the skin incised wound model in mice, the FoxO1 expression of skin in different time periods was detected by immunohistochemistry and Western blotting.

RESULTS

Immunohistochemistry staining showed that FoxO1 was weakly expressed in a few fibroblasts of epidermis, hair follicles, sebaceous glands, vessel endothelium and dermis in the control group. The FoxO1 expression was enhanced in the epidermis and skin appendages around the wound during 6-12 h after injury, which could be detected in the infiltrating neutrophils and a small number of monocytes. FoxO1 was mainly expressed in monocytes during 1-3 d after injury, and in neovascular endothelial cells and fibroblasts during 5-10 d. On the 14th day after injury, the FoxO1 expression still could be detected in a few fibroblasts. The Western blotting results showed that the FoxO1 expression quantity of the tissue samples in injury group was higher than in control group. The FoxO1 expression peaked at 12 h and 7 d after injury.

CONCLUSIONS

FoxO1 is time-dependently expressed in skin wound healing, which can be a useful marker for wound age determination.

Nutrient-Gene Interaction in Colon Cancer, from the Membrane to Cellular Physiology

The International Agency for Research on Cancer recently released an assessment classifying red and processed meat as "carcinogenic to humans" on the basis of the positive association between increased consumption and risk for colorectal cancer. Diet, however, can also decrease the risk for colorectal cancer and be used as a chemopreventive strategy. Bioactive dietary molecules, such as n-3 polyunsaturated fatty acids, curcumin, and fermentable fiber, have been proposed to exert chemoprotective effects, and their molecular mechanisms have been the focus of research in the dietary/chemoprevention field. Using these bioactives as examples, this review surveys the proposed mechanisms by which they exert their effects, from the nucleus to the cellular membrane. In addition, we discuss emerging technologies involving the culturing of colonic organoids to study the physiological effects of dietary bioactives. Finally, we address future challenges to the field regarding the identification of additional molecular mechanisms and other bioactive dietary molecules that can be utilized in our fight to reduce the incidence of colorectal cancer.

A New Model to Study the Role of Arachidonic Acid in Colon Cancer Pathophysiology

A significant increase in cyclooxygenase 2 (COX2) gene expression has been shown to promote cylcooxygenase-dependent colon cancer development. Controversy associated with the role of COX2 inhibitors indicates that additional work is needed to elucidate the effects of arachidonic acid (AA)-derived (cyclooxygenase and lipoxygenase) eicosanoids in cancer initiation, progression, and metastasis. We have recently developed a novel Fads1 knockout mouse model that allows for the investigation of AA-dependent eicosanoid deficiency without the complication of essential fatty acid deficiency. Interestingly, the survival rate of Fads1-null mice is severely compromised after 2 months on a semi-purified AA-free diet, which precludes long-term chemoprevention studies. Therefore, in this study, dietary AA levels were titrated to determine the minimal level required for survival, while maintaining a distinct AA-deficient phenotype. Null mice supplemented with AA (0.1%, 0.4%, 0.6%, 2.0%, w/w) in the diet exhibited a dose-dependent increase (P < 0.05) in AA, PGE2, 6-keto PGF1α, TXB2, and EdU-positive proliferative cells in the colon. In subsequent experiments, null mice supplemented with 0.6% AA diet were injected with a colon-specific carcinogen (azoxymethane) in order to assess cancer susceptibility. Null mice exhibited significantly (P < 0.05) reduced levels/multiplicity of aberrant crypt foci (ACF) as compared with wild-type sibling littermate control mice. These data indicate that (i) basal/minimal dietary AA supplementation (0.6%) expands the utility of the Fads1-null mouse model for long-term cancer prevention studies and (ii) that AA content in the colonic epithelium modulates colon cancer risk. Cancer Prev Res; 9(9); 750-7. ©2016 AACR.

Targeted Deletion of p53 in Lgr5-Expressing Intestinal Stem Cells Promotes Colon Tumorigenesis in a Preclinical Model of Colitis-Associated Cancer

p53 has been shown to mediate cancer stem-like cell function by suppressing pluripotency and cellular dedifferentiation. However, there have been no studies to date that have addressed the specific effects of p53 loss in colonic adult stem cells. In this study, we investigated the consequences of conditionally ablating p53 in the highly relevant Lgr5(+) stem cell population on tumor initiation and progression in the colon. In a mouse model of carcinogen (AOM)-induced colon cancer, tamoxifen-inducible Lgr5-driven deletion of p53 reduced apoptosis and increased proliferation of crypt stem cells, but had no effect on tumor incidence or size. Conversely, in a mouse model of colitis-associated cancer, in which mice are exposed to AOM and the potent inflammation inducer DSS, stem cell-specific p53 deletion greatly enhanced tumor size and incidence in the colon. These novel findings suggest that the loss of p53 function in stem cells enables colonic tumor formation only when combined with DNA damage and chronic inflammation. Furthermore, we propose that stem cell targeting approaches are valuable for interrogating prevention and therapeutic strategies that aim to specifically eradicate genetically compromised stem cells.

Precision Measurement of the Helium Flux in Primary Cosmic Rays of Rigidities 1.9 GV to 3 TV with the Alpha Magnetic Spectrometer on the International Space Station

Knowledge of the precise rigidity dependence of the helium flux is important in understanding the origin, acceleration, and propagation of cosmic rays. A precise measurement of the helium flux in primary cosmic rays with rigidity (momentum/charge) from 1.9 GV to 3 TV based on 50 million events is presented and compared to the proton flux. The detailed variation with rigidity of the helium flux spectral index is presented for the first time. The spectral index progressively hardens at rigidities larger than 100 GV. The rigidity dependence of the helium flux spectral index is similar to that of the proton spectral index though the magnitudes are different. Remarkably, the spectral index of the proton to helium flux ratio increases with rigidity up to 45 GV and then becomes constant; the flux ratio above 45 GV is well described by a single power law.

A bioassay to measure energy metabolism in mouse colonic crypts, organoids, and sorted stem cells

Evidence suggests that targeting cancer cell energy metabolism might be an effective therapeutic approach for selective ablation of malignancies. Using a Seahorse Extracellular Flux Analyzer, we have demonstrated that select environmental agents can alter colonic mitochondrial function by increasing respiration-induced proton leak, thereby inducing apoptosis, a marker of colon cancer risk. To further probe bioenergetics in primary intestinal cells, we developed methodology that can be modified and adapted to measure the bioenergetic profiles of colonic crypts, the basic functional unit of the colon, and colonic organoids, an ex vivo 3D culture of colonic crypts. Furthermore, in combination with the MoFlo Astrios High-Speed Cell Sorter, we were able to measure the bioenergetic profiles of colonic adult stem and daughter cells from Lgr5-EGFP-IRES-creER(T2) transgenic mice. We examined the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a full arylhydrocarbon receptor agonist, known to affect gastrointestinal function and cancer risk, on the bioenergetic profiles of intestinal epithelial cells. Mouse colonic crypts, organoids, or sorted single cells were seeded onto Matrigel-precoated Seahorse XF24 microplates for extracellular flux analysis. Temporal analyses revealed distinct energy metabolic profiles in crypts and organoids challenged with TCDD. Furthermore, sorted Lgr5(+) stem cells exhibited a Warburg-like metabolic profile. This is noteworthy because perturbations in stem cell dynamics are generally believed to represent the earliest step toward colon tumorigenesis. We propose that our innovative methodology may facilitate future in vivo/ex vivo metabolic studies using environmental agents affecting colonocyte energy metabolism.

Effects of forkhead box C2 on carcinogenesis and lymphatic metastasis in endometrial carcinoma

We investigated the distribution of endometrial lymphatic vessels and expression of forkhead box C2 (FOXC2) in normal endometrium during menstrual cycle and in endometrial adenocarcinoma. Full-thickness uterine samples and endometrial adenocarcinoma samples were collected for immunohistochemical analysis using D2-40 and FOXC2 mouse monoclonal antibodies. The lymphatic vessel density (LVD) of the endometrium was significantly reduced compared with the myometrium during the cycle. Intra-tumoral LVD was significantly decreased in both stages of endometrioid adenocarcinoma compared with normal endometrium and myometrium. Intra-tumoral LVD significantly decreased from stage IA to stage IIIC. Peri-tumoral LVD for stage IA and stage IIIC tumors was significantly increased compared with normal endometrial LVD, but decreased compared with normal myometrial LVD. Stage IIIC showed increased peri-tumoral LVD when compared with stage IA. The positive rate of FOXC2 was 73.3% in proliferative endometrium and 80% in secretory endometrium. Secretory endometrium showed significantly increased FOXC2 expression compared with proliferative endometrium. Endometrioid adenocarcinoma showed significantly increased FOXC2 expression compared with normal endometrium, both in the epithelium and stroma. FOXC2 expression in the stroma significantly increased when pelvic and/or para-aotic lymph nodes were involved. FOXC2 was immunolocalized in low-risk endometrial carcinoma in endometrioid adenocarcinoma, but not in normal endometrium. Endometrial lymphatic vessels were located in normal endometrium and myometrium across the menstrual cycle and in intra-and peri-endometrioid adenocarcinoma, and increased in endometrial adenocarcinoma. Peri-tumoral lymphatics were associated with increased lymphatic metastasis. FOXC2 may be associated with the genesis of endometrial carcinoma and lymphangiogensis in endometrial adenocarcinoma in intra- and peri-tumoral lymphatics.

Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station

A precise measurement of the proton flux in primary cosmic rays with rigidity (momentum/charge) from 1 GV to 1.8 TV is presented based on 300 million events. Knowledge of the rigidity dependence of the proton flux is important in understanding the origin, acceleration, and propagation of cosmic rays. We present the detailed variation with rigidity of the flux spectral index for the first time. The spectral index progressively hardens at high rigidities.

Genome-wide polymorphisms between the parents of an elite hybrid rice and the development of a novel set of PCR-based InDel markers

Genome-wide re-sequencing of the Zhenshan 97 (ZS97) and Milyang 46 (MY46) parents of an elite three-line hybrid rice developed in China resulted in the generation of 9.91 G bases of data with an effective sequencing depth of 11.66x and 11.51x, respectively. Detection of genome-wide DNA polymorphisms, single nucleotide polymorphisms (SNPs), short insertions/deletions (InDels; 1-5 bp), and structural variations (SVs), which is an invaluable variation resource for genetic research and molecular marker-assisted breeding, was conducted by comparing whole-genome re-sequencing data. A total of 364,488 SNPs, 61,181 InDels and 6298 SVs were detected in ZS97 and 364,179 SNPs, 61,984 InDels and 6408 SVs were detected in MY46 compared to the 9311 reference sequence. Synteny analysis of the variation revealed a total of 77,013 identical and 181,737 different SNPs and 15,021 identical and 1205 different InDels between ZS97 and MY46, respectively. A total of 180 InDels 3-8 bp in length between ZS97 and MY46 were selected for experimental validation; 160 polymerase chain reaction products were efficiently separated on 6% non-denaturing polyacrylamide gels. Identification of genome-wide variation among the parents of the elite hybrid as well as the set of 160 polymerase chain reaction-based InDel markers will facilitate future genetic studies and the molecular breeding of hybrid rice.

The presence of advanced lesions and associating risk factors for advanced cervical carcinoma in patients with atypical sguamous cells of undetermined significance

PURPOSE OF INVESTIGATION

To characterize histopathological status, high-risk human papillomavirus (hr-HPV) infection status, and associated risk factors in patients with atypical squamous cells of undetermined significance (ASCUS).

MATERIALS AND METHODS

Cervical biopsies obtained from 130 ASCUS patients were subjected to histopathological examination and hr-HPV testing. Associations between advanced lesions and hr-HPV load or age were analyzed, and the confounding factors for high-grade cervical lesions were identified.

RESULTS

Cervical biopsies from ASCUS patients had a wide range of pathological states, ranging from normal to invasive cervical carcinoma. High-risk HPV infection was significantly associated with advanced cervical lesions in ASCUS patients; hr-HPV infection and the number of gestations were risk factors for developing advanced cervical disease.

CONCLUSIONS

A significant portion of ASCUS patients harbor advanced cervical lesions. The number of gestations and hr-HPV infection can increase the risk of developing advanced cervical lesions in ASCUS patients.

Precision Measurement of the (e^{+}+e^{-}) Flux in Primary Cosmic Rays from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station

We present a measurement of the cosmic ray (e^{+}+e^{-}) flux in the range 0.5 GeV to 1 TeV based on the analysis of 10.6 million (e^{+}+e^{-}) events collected by AMS. The statistics and the resolution of AMS provide a precision measurement of the flux. The flux is smooth and reveals new and distinct information. Above 30.2 GeV, the flux can be described by a single power law with a spectral index γ=-3.170±0.008(stat+syst)±0.008(energy scale).

Electron and positron fluxes in primary cosmic rays measured with the alpha magnetic spectrometer on the international space station

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30  GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

High statistics measurement of the positron fraction in primary cosmic rays of 0.5-500 GeV with the alpha magnetic spectrometer on the international space station

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200  GeV the positron fraction no longer exhibits an increase with energy.

Mechanisms by Which Pleiotropic Amphiphilic n-3 PUFA Reduce Colon Cancer Risk

Colorectal cancer is one of the major causes of cancer-related mortality in both men and women worldwide. Genetic susceptibility and diet are primary determinants of cancer risk and tumor behavior. Experimental, epidemiological, and clinical data substantiate the beneficial role of n-3 polyunsaturated fatty acids (PUFA) in preventing chronic inflammation and colon cancer. From a mechanistic perspective, n-3 PUFA are pleiotropic and multifaceted with respect to their molecular mechanisms of action. For example, this class of dietary lipid uniquely alters membrane structure/ cytoskeletal function, impacting membrane receptor function and downstream signaling cascades, including gene expression profiles and cell phenotype. In addition, n-3 PUFA can synergize with other potential anti-tumor agents, such as fermentable fiber and curcumin. With the rising prevalence of diet-induced obesity, there is also an urgent need to elucidate the link between chronic inflammation in adipose tissue and colon cancer risk in obesity. In this review, we will summarize recent developments linking n-3 PUFA intake, membrane alterations, epigenetic modulation, and effects on obesity-associated colon cancer risk.

n-3 PUFAs reduce T-helper 17 cell differentiation by decreasing responsiveness to interleukin-6 in isolated mouse splenic CD4⁺ T cells

Cluster of differentiation 4(+) (CD4(+)) effector T-cell subsets [e.g., T-helper (Th) 1 and Th17] are implicated in autoimmune and inflammatory disorders such as multiple sclerosis, psoriasis, and rheumatoid arthritis. Interleukin (IL)-6 is a pleiotropic cytokine that induces Th17 polarization via signaling through the membrane-bound transducer glycoprotein 130 (GP130). Previously, we demonstrated that n-3 (ω-3) polyunsaturated fatty acids (PUFAs) reduce CD4(+) T-cell activation and differentiation into pathogenic Th17 cells by 25-30%. Here we report that n-3 PUFAs alter the response of CD4(+) T cells to IL-6 in a lipid raft membrane-dependent manner. Naive splenic CD4(+) T cells from fat-1 transgenic mice exhibited 30% lower surface expression of the IL-6 receptor. This membrane-bound receptor is known to be shed during cellular activation, but the release of soluble IL-6 receptor after treatment with anti-CD3 and anti-CD28 was not changed in the CD4(+) T cells from fat-1 mice, suggesting that the decrease in surface expression was not due to ectodomain release. We observed a significant 20% decrease in the association of GP130 with lipid rafts in activated fat-1 CD4(+) T cells and a 35% reduction in GP130 homodimerization, an obligate requirement for downstream signaling. The phosphorylation of signal transducer and activator of transcription 3 (STAT3), a downstream target of IL-6-dependent signaling, was also decreased by 30% in response to exogenous IL-6 in fat-1 CD4(+) T cells. Our results suggest that n-3 PUFAs suppress Th17 cell differentiation in part by reducing membrane raft-dependent responsiveness to IL-6, an essential polarizing cytokine.

Mitochondrial glycerol-3-phosphate acyltransferase-1 is essential for murine CD4(+) T cell metabolic activation

Glycerol-3-phosphate acyltransferase-1 is the first rate limiting step in de novo glycerophospholipid synthesis. We have previously demonstrated that GPAT-1 deletion can significantly alter T cell function resulting in a T cell phenotype similar to that seen in aging. Recent studies have suggested that changes in the metabolic profile of T cells are responsible for defining specific effector functions and T cell subsets. Therefore, we determined whether T cell dysfunction in GPAT-1 (-/-) CD4(+) T cells could be explained by changes in cellular metabolism. We show here for the first time that GPAT-1 (-/-) CD4(+) T cells exhibit several key metabolic defects. Striking decreases in both the oxygen consumption rate (OCR) and the extracellular acidification rate (ECAR) were observed in GPAT-1 (-/-) CD4(+) T cells following CD3/CD28 stimulation indicating an inherent cellular defect in energy production. In addition, the spare respiratory capacity (SRC) of GPAT-1 (-/-) CD4+ T cells, a key indicator of their ability to cope with mitochondrial stress was significantly decreased. We also observed a significant reduction in mitochondrial membrane potential in GPAT-1 (-/-) CD4(+) T cells compared to their WT counterparts, indicating that GPAT-1 deficiency results in altered or dysfunctional mitochondria. These data demonstrate that deletion of GPAT-1 can dramatically alter total cellular metabolism under conditions of increased energy demand. Furthermore, altered metabolic response following stimulation may be the defining mechanism underlying T cell dysfunction in GPAT-1 (-/-) CD4(+) T cells. Taken together, these results indicate that GPAT-1 is essential for the response to the increased metabolic demands associated with T cell activation.

Differential effects of 2- and 3-series E-prostaglandins on in vitro expansion of Lgr5+ colonic stem cells

Arachidonic acid (20:4(Δ5,8,11,14), AA)-derived prostaglandin E2 (PGE2) promotes colon cancer development. In contrast, chemoprotective n-3 polyunsaturated fatty acids supplant AA, thereby decreasing PGE2 biosynthesis in colonocytes, with eicosapentaenoic acid (20:5(Δ5,8,11,14,17), EPA) in particular being metabolized to a novel 3-series E-prostaglandin (PGE3), a putative anti-tumorigenic-cyclooxygenase metabolite. Because transformation of adult stem cells is an extremely important route toward initiating intestinal cancer, we utilized the leucine-rich-repeat-containing G-protein-coupled receptor 5 (Lgr5)-enhanced green fluorescent protein-internal ribosome entry site (IRES)-creER(T2) knock-in mouse model to isolate and culture colonic organoids, in order to document ex vivo responses to exogenous PGE2 and PGE3. Colonic crypts were isolated from transgenic mice and cultured in a Matrigel-based three-dimensional platform. Organoids were treated with exogenous PGE2, PGE3 or dimethyl sulfoxide (vehicle control) for 5 days and the number of viable organoids was recorded daily. Subsequently, samples were processed for immunohistochemistry, flow cytometry and real-time PCR analyses. PGE2 promoted optimal organoid growth and induced significantly higher levels of cell proliferation (P < 0.05) compared with PGE3 and control. In contrast, the Lgr5-green fluorescent protein-positive stem cell number was uniquely elevated by >2-fold in PGE2-treated cultures compared with PGE3 and control. This coincided with the upregulation of stem-cell-related Sox9, Axin2 and Cd44 messenger RNAs. Our results demonstrate that relative to AA-derived PGE2, a known promoter of colon tumorigenesis, EPA-derived PGE3 has diminished ability to support colonic stem cell expansion in mouse colonic organoids.

Abstract CN02-03: Fat-fiber combination: The missing ingredient?

In a series of seminal preclinical studies, we have demonstrated that the pleiotropic bioactive components generated by fish oil (containing DHA) and fermentable fiber act coordinately to protect against colon cancer, in part, by enhancing apoptosis at the base of the crypt throughout all stages of colon tumorigenesis. This is significant because the induction of apoptosis represents a potent cellular mechanism against cancer. With respect to a mechanism of action, pectin is metabolized by microbes in the lumen of the gut to butyrate and other short chain fatty acids. We have recently shown that DHA and butyrate synergize to enhance a p53-independent, oxidation sensitive, mitochondrial Ca2+-dependent (intrinsic) apoptotic pathway in the colon. These data indicate that highly fermentable fiber, which generates butyrate in the colon, has enhanced chemotherapeutic value when n-3 PUFA is the lipid source.

Butyrate (a fiber fermentation product) is (i) the preferred energy source for colonocytes, (ii) contributes to acetyl CoA production where it serves as an essential cofactor for Histone Acetyl Transferases, and (iii) is a Histone Deacetylase inhibitor known to alter transcriptional regulation by remodeling chromatin structure. Consequently, we also investigated the “epigenetic therapeutic” potential of chemoprotective dietary treatment (combined fish oil and pectin) in rats and mice exposed to carcinogen (AOM). Specifically, we determined how diet modulates colonic chromatin structure, microRNAs and their target genes following exposure to AOM. Oncogenic PTK2B, PDE4B and TCF4, targeted by miR-19b, miR-26b and miR-203, respectively, were suppressed by the chemoprotective (fish oil and pectin) combination diet compared to a control diet at both the mRNA and protein levels.

The interaction of total dietary fat and fiber on colorectal cancer (CRC) risk has been assessed and found to be null among postmenopausal women. However, the evaluation of specific sub-types of dietary fiber and fatty acids, in combination, with respect to risk of CRC in a large prospective cohort has yet to be undertaken. This is an important evaluation considering the varied biologic, biochemical and metabolic roles of dietary fat and fiber subtypes. Collectively, these critical observations emphasize the need to examine the specific chemical characteristics of lipids and fibers in the diet as opposed to simply focusing on the overall lipid and fiber content of diets. The failure to address an interaction between types of fat and fiber may explain why the chemoprotective effects of n-3 PUFA are obscured in prospective cohort studies.

Citation Format: Robert S. Chapkin, Laurie A. Davidson, Johanna W. Lampe, Nancy D. Turner, Yang-Yi Fan, Joanne R. Lupton. Fat-fiber combination: The missing ingredient? [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr CN02-03.

Inhibitory effects of omega-3 fatty acids on injury-induced epidermal growth factor receptor transactivation contribute to delayed wound healing

Epidermal growth factor receptor (EGFR)-mediated signaling is required for optimal intestinal wound healing. Since n-3 polyunsaturated fatty acids (PUFA), specifically docosahexaenoic acid (DHA), alter EGFR signaling and suppress downstream activation of key signaling pathways, we hypothesized that DHA would be detrimental to the process of intestinal wound healing. Using a mouse immortalized colonocyte model, DHA uniquely reduced EGFR ligand-induced receptor activation, whereas DHA and its metabolic precursor eicosapentaenoic acid (EPA) reduced wound-induced EGFR transactivation compared with control (no fatty acid or linoleic acid). Under wounding conditions, the suppression of EGFR activation was associated with a reduction in downstream activation of cytoskeletal remodeling proteins (PLCγ1, Rac1, and Cdc42). Subsequently, DHA and EPA reduced cell migration in response to wounding. Mice were fed a corn oil-, DHA-, or EPA-enriched diet prior to intestinal wounding (2.5% dextran sodium sulfate for 5 days followed by termination after 0, 3, or 6 days of recovery). Mortality was increased in EPA-fed mice and colonic histological injury scores were increased in EPA- and DHA-fed mice compared with corn oil-fed (control) mice. Although kinetics of colonic EGFR activation and downstream signaling (PLCγ1, Rac1, and Cdc42) were delayed by both n-3 PUFA, colonic repair was increased in EPA- relative to DHA-fed mice. These results indicate that, during the early response to intestinal wounding, DHA and EPA uniquely delay the activation of key wound-healing processes in the colon. This effect is mediated, at least in part, via suppression of EGFR-mediated signaling and downstream cytoskeletal remodeling.

A missense mutant of the PPAR-γ gene associated with carcass and meat quality traits in Chinese cattle breeds

The peroxisome proliferator-activated receptor gamma (PPAR-γ) is a key molecule in adipocyte differentitation; it transactivates multiple target genes in lipid metabolic pathways. Using PCR-SSCP and DNA sequencing, we evaluated a potential association of an SNP (72472 G﹥T in exon7) of the bovine PPAR-γ gene with carcass and meat quality traits in 660 individuals from five Chinese indigenous cattle breeds, Qinchuan (QC), Luxi (LX), Nanyang (NY), Jiaxian (JX), and Xianan (XN). This 72472 G﹥T mutation identified a missense mutation, Q448H. Two alleles were named C and D. Allele frequencies of PPAR-γ-C/D in the five breeds were 0.7815/0.2185, 0.9/0.1, 0.7442/0.2558, 0.7051/0.2949, and 0.8333/0.1667 for QC, NY, JX, LX, and XN, respectively. Except for the XN breed, all breeds were in Hardy-Weinberg equilibrium at this locus. The polymorphism information content was low for NY and XN (0.16 and 0.24, respectively), while it was moderately high for QC, JX, and LX (0.28, 0.31 and 0.33, respectively). Correlation analysis showed significant association of this missense mutation with carcass length, backfat thickness and water holding capacity in the QC breed. Animals with the genotype CD had significantly greater carcass length than those with genotypes CC and DD, while animals with genotype CC had significantly greater backfat thickness than those with genotypes CD and DD. Animals with genotype CC had lower water holding capacity than those with the genotypes CD and DD. In conclusion, this locus is a candidate for a major quantitative trait locus affecting production traits and could be used for beef breeding selection.

Targeted overexpression of inducible 6-phosphofructo-2-kinase in adipose tissue increases fat deposition but protects against diet-induced insulin resistance and inflammatory responses

Increasing evidence demonstrates the dissociation of fat deposition, the inflammatory response, and insulin resistance in the development of obesity-related metabolic diseases. As a regulatory enzyme of glycolysis, inducible 6-phosphofructo-2-kinase (iPFK2, encoded by PFKFB3) protects against diet-induced adipose tissue inflammatory response and systemic insulin resistance independently of adiposity. Using aP2-PFKFB3 transgenic (Tg) mice, we explored the ability of targeted adipocyte PFKFB3/iPFK2 overexpression to modulate diet-induced inflammatory responses and insulin resistance arising from fat deposition in both adipose and liver tissues. Compared with wild-type littermates (controls) on a high fat diet (HFD), Tg mice exhibited increased adiposity, decreased adipose inflammatory response, and improved insulin sensitivity. In a parallel pattern, HFD-fed Tg mice showed increased hepatic steatosis, decreased liver inflammatory response, and improved liver insulin sensitivity compared with controls. In both adipose and liver tissues, increased fat deposition was associated with lipid profile alterations characterized by an increase in palmitoleate. Additionally, plasma lipid profiles also displayed an increase in palmitoleate in HFD-Tg mice compared with controls. In cultured 3T3-L1 adipocytes, overexpression of PFKFB3/iPFK2 recapitulated metabolic and inflammatory changes observed in adipose tissue of Tg mice. Upon treatment with conditioned medium from iPFK2-overexpressing adipocytes, mouse primary hepatocytes displayed metabolic and inflammatory responses that were similar to those observed in livers of Tg mice. Together, these data demonstrate a unique role for PFKFB3/iPFK2 in adipocytes with regard to diet-induced inflammatory responses in both adipose and liver tissues.

Characterization of an arachidonic acid-deficient (Fads1 knockout) mouse model

Arachidonic acid (20:4(Δ5,8,11,14), AA)-derived eicosanoids regulate inflammation and promote cancer development. Previous studies have targeted prostaglandin enzymes in an attempt to modulate AA metabolism. However, due to safety concerns surrounding the use of pharmaceutical agents designed to target Ptgs2 (cyclooxygenase 2) and its downstream targets, it is important to identify new targets upstream of Ptgs2. Therefore, we determined the utility of antagonizing tissue AA levels as a novel approach to suppressing AA-derived eicosanoids. Systemic disruption of the Fads1 (Δ5 desaturase) gene reciprocally altered the levels of dihomo-γ-linolenic acid (20:3(Δ8,11,14), DGLA) and AA in mouse tissues, resulting in a profound increase in 1-series-derived and a concurrent decrease in 2-series-derived prostaglandins. The lack of AA-derived eicosanoids, e.g., PGE₂ was associated with perturbed intestinal crypt proliferation, immune cell homeostasis, and a heightened sensitivity to acute inflammatory challenge. In addition, null mice failed to thrive, dying off by 12 weeks of age. Dietary supplementation with AA extended the longevity of null mice to levels comparable to wild-type mice. We propose that this new mouse model will expand our understanding of how AA and its metabolites mediate inflammation and promote malignant transformation, with the eventual goal of identifying new drug targets upstream of Ptgs2.

Interactive effects of fatty acid and butyrate-induced mitochondrial Ca²⁺ loading and apoptosis in colonocytes

BACKGROUND

The combination of fish oil-derived docosahexaenoic acid (DHA) (22:6; omega 3 [n-3]) and butyrate (4:0), a fiber fermentation product, synergized to enhance colonocyte apoptosis by inducing a p53-independent, oxidation sensitive, mitochondrial Ca(2+) -dependent (intrinsic) pathway.

METHODS

In this study, the authors probed the specificity of n-6 and n-3 polyunsaturated fatty acid induction of Ca(2+) -dependent proapoptotic events in immortalized young adult mouse colonocytes and determined whether combinations of polyunsaturated fatty acid and butyrate could trigger endoplasmic reticulum (ER) stress conditions, thereby promoting mitochondrial Ca(2+) overload. Cultures were treated with 0 μM to 50 μM of DHA (22:6; n-3), EPA (20:5; n-3), arachidoinic acid (AA) (20:4; n-6), linoleic acid (18:2; n-6), or oleic acid (OA) (18:1; n-9) for a total of 72 hours with or without RU-360 (to inhibit the mitochondrial Ca(2+) uniporter) for 30 minutes before cotreatment with butyrate (0 mM or 5 mM).

RESULTS

Combined DHA and butyrate maximally induced apoptosis and mitochondrial-to-cytosolic Ca(2+) levels. By comparison, EPA, a precursor to DHA, was minimally effective. Similarly, AA and OA in combination with butyrate had no effect on mitochondrial Ca(2+) or apoptosis compared with butyrate alone. DHA with or without butyrate cotreatment minimally altered the ER stress-regulated genes DNA damage-inducible transcript 3, the CCAAT enhancer binding protein (C/EBP) homologous protein (CHOP), and eukaryotic initiation factor 2α.

CONCLUSIONS

The current data indicated that butyrate and DHA, but not EPA, worked in a coordinated fashion to trigger an ER-independent, Ca(2+) -dependent, intrinsic mitochondrial-mediated apoptotic pathway in colonocytes.

Dietary fish oil promotes colonic apoptosis and mitochondrial proton leak in oxidatively stressed mice

An alteration of mitochondrial function can result in disruption of redox homeostasis and is associated with abnormal cancer cell growth. Manganese superoxide dismutase (SOD2) and glutathione peroxidase 4 (Gpx4) are two of the most important antioxidant defense enzymes that protect cells against oxidative stress. We had previously shown that n-3 polyunsaturated fatty acids (PUFA) promote colonocyte apoptosis, a marker of colon cancer risk, in part by enhancing phospholipid oxidation. To elucidate the mechanisms regulating oxidative stress-induced apoptosis in vivo, we fed heterozygous SOD2(Het), Gpx4(Het), and transgenic Gpx4(Tg) mice diets containing either 15% corn oil by weight (CO, enriched in n-6 PUFA) or 3.5% CO + 11.5% fish oil (FO, enriched in n-3 PUFA) for 4 weeks. Our data showed that (i) genetic predeposition to oxidative stress facilitates apoptosis in the mouse colon (Gpx4(Het) > SOD2(Het) > Wt > Gpx4(Tg)), (ii) dietary n-3 PUFA have an additive effect on the induction of apoptosis in Gpx4(Het) and SOD2(Het) mice; and (iii) dietary n-3 PUFA reverse the phenotype in oxidatively protected Gpx4(Tg) mice by elevating apoptosis to a level observed in wild-type (Wt; control) animals. Complimentary experiments examining colonic mitochondrial bioenergetic profiles indicate that FO-fed mice exhibit a significantly (P < 0.05) increased respiration-induced proton leak relative to control CO treatment. This finding was consistent with a loss of membrane potential in response to chronic oxidative stress and supports the contention that n-3 PUFA alter mitochondrial metabolic activity, thereby enhancing apoptosis and reducing colon cancer risk.