Project description:Essential fatty acids (FA) are not only energy-rich molecules; they are also an important component of the membrane bilayer and recently have been implicated in induction of fatty acid synthase (FAS) and other genes. Using gene chip analysis, we have found that arachidonic acid (AA), an omega-6 fatty acid, induced 11 genes that are regulated by NFkappaB. We verified gene induction by omega-6 fatty acids including COX2, IKBA, NFKB, GMCSF, IL1B, CXCL1, TNFA, IL6, LTA, IL8, PPARG, and ICAM1 using qRTPCR. PGE2 synthesis was increased within 5min of addition of AA. Analysis of upstream signal transduction showed that within 5min of FA addition, phophatidylinositol 3-kinase (PI3K) was significantly activated followed by activation of Akt at 30min. ERK1 and 2, p38, and SAPK/JNK were not phosphorylated after omega-6 FA addition. Thirty minutes after FA addition, we found a significant 3-fold increase in translocation of NFkappaB transcription factor to the nucleus. Addition of non-steroidal anti-inflammatory drug (NSAID) caused a decrease in cox-2 protein synthesis, PGE2 synthesis as well as inhibition of PI3K activation. We have previously shown that AA induced proliferation is also blocked (P<0.001) by PI3K inhibitor LY294002. LY294002 also significantly inhibited the AA induced gene expression of COX2, IL1B, GMCSF, and ICAM1. Taken together, the data suggests that AA via conversion to PGE2 plays an important role in stimulation of growth related genes and proliferation via PI3K signaling and NFkappaB translocation to the nucleus. Keywords: Time course of Prostate Cancer Activation by Arachidonic Acid
Project description:Essential fatty acids (FA) are not only energy-rich molecules; they are also an important component of the membrane bilayer and recently have been implicated in induction of fatty acid synthase (FAS) and other genes. Using gene chip analysis, we have found that arachidonic acid (AA), an omega-6 fatty acid, induced 11 genes that are regulated by NFkappaB. We verified gene induction by omega-6 fatty acids including COX2, IKBA, NFKB, GMCSF, IL1B, CXCL1, TNFA, IL6, LTA, IL8, PPARG, and ICAM1 using qRTPCR. PGE2 synthesis was increased within 5min of addition of AA. Analysis of upstream signal transduction showed that within 5min of FA addition, phophatidylinositol 3-kinase (PI3K) was significantly activated followed by activation of Akt at 30min. ERK1 and 2, p38, and SAPK/JNK were not phosphorylated after omega-6 FA addition. Thirty minutes after FA addition, we found a significant 3-fold increase in translocation of NFkappaB transcription factor to the nucleus. Addition of non-steroidal anti-inflammatory drug (NSAID) caused a decrease in cox-2 protein synthesis, PGE2 synthesis as well as inhibition of PI3K activation. We have previously shown that AA induced proliferation is also blocked (P<0.001) by PI3K inhibitor LY294002. LY294002 also significantly inhibited the AA induced gene expression of COX2, IL1B, GMCSF, and ICAM1. Taken together, the data suggests that AA via conversion to PGE2 plays an important role in stimulation of growth related genes and proliferation via PI3K signaling and NFkappaB translocation to the nucleus.
Project description:Estrogen receptor dependent genomic expression profiles in breast cancer cells in response to fatty acids. Estrogen receptor positive cells respond better to omega 3 treatments. two condition experiments: ER positive and negative breast cancer cells exposed to two fatty acids: omega-3 (eicosapentanoic acid) and 6 (arachidonic acid).
Project description:Within the secreted phospholipase A2 (sPLA2) family, group X sPLA2 (sPLA2-X) has the highest capacity to hydrolyze cellular membranes and has long been thought to promote inflammation by releasing arachidonic acid (AA), a precursor of pro-inflammatory eicosanoids. Unexpectedly, we found that transgenic mice globally overexpressing human sPLA2-X (PLA2G10-Tg) displayed striking immunosuppressive and lean phenotypes with lymphopenia and increased M2-like macrophages, accompanied by marked elevation of free omega-3 polyunsaturated fatty acids (PUFAs) and their metabolites. Studies using Pla2g10-deficient mice revealed that endogenous sPLA2-X, which is highly expressed in the colon epithelium and spermatozoa, mobilized omega-3 PUFAs or their metabolites to protect against dextran sulfate sodium (DSS)-induced colitis and to promote fertilization, respectively. In colitis, sPLA2-X deficiency increased colorectal expression of Th17 cytokines, and omega-3 PUFAs attenuated their production by lamina propria cells partly through the fatty acid receptor GPR120. In comparison, cytosolic phospholipase A2 (cPLA2alpha) protects from colitis by mobilizing omega-6 AA metabolites including prostaglandin E2. Thus, our results underscore a previously unrecognized role of sPLA2-X as an omega-3 PUFA mobilizer in vivo, segregated mobilization of omega-3 and omega-6 PUFA metabolites by sPLA2-X and cPLA2alpha, respectively, in protection against colitis, and the novel role of a particular sPLA2-X-driven PUFA in fertilization.
Project description:Free fatty acids play an important role during infection by modulating immune responses, but also by directly functioning as antimicrobials. Particularly, the host’s long chain polyunsaturated fatty acids, not commonly found in bacterial pathogens, have significant antibacterial potential. Of these arachidonic acid (AA) is in high abundance, and in this study we show that upon infection with the Streptococcus pneumoniae the AA concentration in the blood increases. Hence, we investigated the transcriptmoic effects of AA on this extremely problematic bacterial pathogen.
Project description:The combination of immune checkpoint blockade and chemotherapies is the standard-of-care for triple negative breast cancer (TNBC). However, initially responsive tumors can still develop recurrences, suggesting acquired resistance mechanisms that remain poorly understood. Herein, we discovered that TNBC cells surviving anti-PD-1 and chemotherapy treatment accumulated neutral lipids. Disrupting lipid droplet formation in cancer cells reversed resistance and mitigated the immunosuppressive microenvironment. Single-cell RNA sequencing revealed a subset of neutrophils exhibiting a lipid-laden phenotype similar to adjacent tumor cells. Mechanistically, tumor-derived extracellular vesicles carrying lipids including arachidonic acid (AA) mediated neutrophil reprogramming. Blocking dietary intake of omega-6 fatty acids or inhibiting fatty acid elongation for AA synthesis restored antitumor immunity and re-sensitized the resistant tumors to anti-PD-1 and chemotherapy treatment. In human patients, AA metabolism-related pathways correlated with neutrophil enrichment. Overall, we demonstrate how lipid accumulation in TNBC cells leads to immune suppression and therapy resistance.
Project description:Experimental studies confirmed n-6 type polyunsaturated fatty acid as pro-carcinogenic factor and n-3 fatty acid as cancer restraining agent; though their mode of action on tumor cells are still unclear. To review the contrasting effect of omega-3 and omega-6 fatty acids over carcinoma by studying genomic alteration in treated cancer cells, two members from each family of PUFAs, namely EPA and DHA from n-3 PUFA family and, AA and LA from n-6 PUFA family was selected to treat four breast cancer cell lines: MDA-MB231, MDA-MB435S, HCC2218 and MCF-7 for two time period- 6hr and 24hr.
Project description:Oxylipins derived from dietary polyunsaturated fatty acids (PUFAs) are key determinants of intestinal health, homeostasis and inflammatory disorders, such as colitis-associated colorectal cancer (CAC). Previous research has independently linked a high dietary omega (ω)-6:ω-3 PUFA ratio, or intestinal helminth infection, to an increased risk of CAC. However, whether these two factors interact to exacerbate disease risk and whether oxylipins contribute to this is unknown. In this study, we report that infection with the helminth Heligmosomoides polygyrus bakeri (Hpb) exacerbates tumour formation when combined with a high ω-6:ω-3 PUFA ratio diet. Dietary increases in tumour burden correlated with heightened levels of arachidonic acid (AA) and AA-derived lipoxygenase (LOX) oxylipins in the colon, including the 12/15-LOX product 12-hydroxyeicosatetraenoic acid, prior to disease onset. Although helminth infection further increased the production of 12/15-LOX oxylipins and increased expression of Alox15, responsible for producing these metabolites, inhibition of cyclooxygenase-dependent prostaglandin production with aspirin prevented helminth-exacerbation of disease. Helminth-infected mice exhibited increased phosphorylation of β-catenin in the colon, which was inhibited by EP2 and 4 antagonists. Moreover, administration of an EP agonist increased tumour burden in naive mice fed a high w-6:w-3 PUFA ratio diet, to the levels seen in helminth-exacerbation of disease. These data suggest that dietary changes in fatty acid composition coordinate with helminth-induced activation of EP signalling to exacerbate tumour development.
Project description:We report the miRNA profile of murine macrophages (cell line: RAW264.7) after supplementation with polyunsaturated fatty acids (PUFA) and stimulation with LTA. The fatty acids docosahexaenoic acid (DHA, C22:6n3) or arachidonic acid (AA, C20:4n6) were included in the culture medium in concentrations of 15 µmol/L using ethanol as a vehicle (0.2 % v/v final ethanol concentration). Cells were cultured in the enriched media totaling 72 h. Stimulation of cells was performed in the last 24 h of fatty acid supplementation by addition of LTA (0.5 µg/mL; from Staphylococcus aureus).
Project description:We report the transcriptome profile of murine macrophages (cell line: RAW264.7) after supplementation with polyunsaturated fatty acids (PUFA) and stimulation with LTA. The fatty acids docosahexaenoic acid (DHA, C22:6n3) or arachidonic acid (AA, C20:4n6) were included in the culture medium in concentrations of 15 µmol/L using ethanol as a vehicle (0.2 % v/v final ethanol concentration). Cells were cultured in the enriched media totaling 72 h. Stimulation of cells was performed in the last 24 h of fatty acid supplementation by addition of LTA (0.5 µg/mL; from Staphylococcus aureus).