Over-the-counter fish oil supplementation and pro-resolving and pro-inflammatory lipid mediators in rheumatoid arthritis.

OBJECTIVE: Little is known about the effects of over-the-counter fish oil (FO) supplements on circulating omega-3 polyunsaturated fatty acid (n-3 PUFA)-derived specialized pro-resolving mediators (SPMs), nor about whether having a chronic inflammatory disease such as rheumatoid arthritis (RA) influences SPM levels. We investigated associations between over-the-counter n-3 PUFA FO supplementation and circulating SPMs among patients with vs. without RA. METHODS: We studied 104 participants: 26 with RA taking FO matched by age and sex to 26 with RA not taking FO, 26 without RA taking FO, and 26 without RA not taking FO. Targeted-liquid chromatography-tandem mass spectroscopy was performed on patient plasma to identify and quantify 27 lipid mediators (including eicosanoids and SPMs). We performed t-tests and then multivariable linear regression analyses to assess whether having RA or taking FO supplements was associated with circulating lipid mediator concentrations, adjusting for age, race, sex, smoking, body mass index, and current medication use (statins, prednisone and immunomodulators among RA cases only). We tested for interactions between FO supplementation and RA status. We also conducted Spearman's correlations between EPA, DHA, and ARA and their downstream metabolites. RESULTS: Among patients who were taking FO compared to those who were not, in multivariable- adjusted analyses, SPM substrates EPA and DHA were both elevated as were several of their pro-resolving bioactive products, including 15- and 18-HEPE from EPA, and 14- and 17-HDHA from DHA, which are substrates for specific SPMs. While E-series and D-series resolvins were present and identified, we did not find statistical elevations of other SPMs. Results were similar among patients with RA and patients without RA, taking vs. not taking FO supplementation (no formal statistical interaction observed). There was a strong positive correlation between EPA and DHA and their immediate downstream SPM precursors (18-HEPE and15-HEPE from EPA; 17-HDHA and 14-HDHA from DHA) among all patients. CONCLUSION: Patients taking FO supplements, regardless of RA status, not only had higher blood levels of EPA and DHA, but also of their enzymatic products 18-HEPE (E-series resolvin precursors), 15-HEPE and 17-HDHA (D-series resolvin and protectin precursors). Patients with RA, an inflammatory autoimmune disease, may be able to augment some SPM precursor reserves, similarly to matched controls without RA, by taking oral FO supplements.

Passive Smoking Throughout the Life Course and the Risk of Incident Rheumatoid Arthritis in Adulthood Among Women.

OBJECTIVE: To investigate passive smoking throughout the life course and the risk of rheumatoid arthritis (RA), while accounting for personal smoking. METHODS: We analyzed the Nurses' Health Study II prospective cohort, using information collected via biennial questionnaires. We assessed the influence of 1) maternal smoking during pregnancy (in utero exposure), 2) childhood parental smoking, and 3) years lived with smokers since age 18. Incident RA and serostatus were determined by medical record review. Using the marginal structural model framework, we estimated the controlled direct effect of each passive smoking exposure on adult incident RA risk by serologic phenotype, controlling for early-life factors and time-updated adulthood factors including personal smoking. RESULTS: Among 90,923 women, we identified 532 incident RA cases (66% seropositive) during a median of 27.7 years of follow-up. Maternal smoking during pregnancy was associated with RA after adjustment for confounders, with a hazard ratio (HR) of 1.25 (95% confidence interval [95% CI] 1.03-1.52), but not after accounting for subsequent smoking exposures. Childhood parental smoking was associated with seropositive RA after adjustment for confounders (HR 1.41 [95% CI 1.08-1.83]). In the controlled direct effect analyses, childhood parental smoking was associated with seropositive RA (HR 1.75 [95% CI 1.03-2.98]) after controlling for adulthood personal smoking, and the association was accentuated among ever smokers (HR 2.18 [95% CI 1.23-3.88]). There was no significant association of adulthood passive smoking with RA (HR 1.30 for ≥20 years of living with a smoker versus none [95% CI 0.97-1.74]). CONCLUSION: We found a potential direct influence of childhood parental smoking on adult-onset incident seropositive RA even after controlling for adulthood personal smoking.

MET amplification increases the metastatic spread of EGFR-mutated NSCLC.

BACKGROUND: Five to 20% of metastatic EGFR-mutated non-small cell lung cancers (NSCLC) develop acquired resistance to EGFR tyrosine kinase inhibitors (EGFR-TKI) through MET amplification. The effects of MET amplification on tumor and patient phenotype remain unknown. METHODS: We investigated,in vitro and in vivo, the impact of MET amplification on the biological properties of the HCC827 cell line, derived from an EGFR-mutated NSCLC. We further evaluated the time to new metastases after EGFR-TKI progression in EGFR-mutated NSCLC, exhibiting MET amplification or high MET overexpression. RESULTS: MET amplification significantly enhanced proliferation, anchorage independent growth, anoikis resistance, migration, and induced an epithelial to mesenchymal transition. In vivo, MET amplification significantly increased the tumor growth and metastatic spread. Treatment with a MET-TKI reversed this aggressive phenotype. We found that EGFR-mutated NSCLC patients exhibiting MET amplification on a re-biopsy, performed after EGFR-TKI progression, displayed a shorter time to new metastases after EGFR-TKI progression than patients with high MET overexpression but no MET amplification. CONCLUSION: MET amplification increases metastatic spread even in the context of an already pre-existing strong driver mutation such as EGFR mutation. These results prompt development of therapeutic strategies aiming at preventing emergence of MET amplification.

ETV4 transcription factor and MMP13 metalloprotease are interplaying actors of breast tumorigenesis.

BACKGROUND: The ETS transcription factor ETV4 is involved in the main steps of organogenesis and is also a significant mediator of tumorigenesis and metastasis, such as in breast cancer. Indeed, ETV4 is overexpressed in breast tumors and is associated with distant metastasis and poor prognosis. However, the cellular and molecular events regulated by this factor are still misunderstood. In mammary epithelial cells, ETV4 controls the expression of many genes, MMP13 among them. The aim of this study was to understand the function of MMP13 during ETV4-driven tumorigenesis. METHODS: Different constructs of the MMP13 gene promoter were used to study the direct regulation of MMP13 by ETV4. Moreover, cell proliferation, migration, invasion, anchorage-independent growth, and in vivo tumorigenicity were assayed using models of mammary epithelial and cancer cells in which the expression of MMP13 and/or ETV4 is modulated. Importantly, the expression of MMP13 and ETV4 messenger RNA was characterized in 456 breast cancer samples. RESULTS: Our results revealed that ETV4 promotes proliferation, migration, invasion, and anchorage-independent growth of the MMT mouse mammary tumorigenic cell line. By investigating molecular events downstream of ETV4, we found that MMP13, an extracellular metalloprotease, was an ETV4 target gene. By overexpressing or repressing MMP13, we showed that this metalloprotease contributes to proliferation, migration, and anchorage-independent clonogenicity. Furthermore, we demonstrated that MMP13 inhibition disturbs proliferation, migration, and invasion induced by ETV4 and participates to ETV4-induced tumor formation in immunodeficient mice. Finally, ETV4 and MMP13 co-overexpression is associated with poor prognosis in breast cancer. CONCLUSION: MMP13 potentiates the effects of the ETV4 oncogene during breast cancer genesis and progression.

TMPRSS2-ERG fusion promotes prostate cancer metastases in bone.

Bone metastasis is the major deleterious event in prostate cancer (PCa). TMPRSS2-ERG fusion is one of the most common chromosomic rearrangements in PCa. However, its implication in bone metastasis development is still unclear. Since bone metastasis starts with the tropism of cancer cells to bone through specific migratory and invasive processes involving osteomimetic capabilities, it is crucial to better our understanding of the influence of TMPRSS2-ERG expression in the mechanisms underlying the bone tropism properties of PCa cells. We developed bioluminescent cell lines expressing the TMPRSS2-ERG fusion in order to assess its role in tumor growth and bone metastasis appearance in a mouse model. First, we showed that the TMPRSS2-ERG fusion increases cell migration and subcutaneous tumor size. Second, using intracardiac injection experiments in mice, we showed that the expression of TMPRSS2-ERG fusion increases the number of metastases in bone. Moreover, TMPRSS2-ERG affects the pattern of metastatic spread by increasing the incidence of tumors in hind limbs and spine, which are two of the most frequent sites of human PCa metastases. Finally, transcriptome analysis highlighted a series of genes regulated by the fusion and involved in the metastatic process. Altogether, our work indicates that TMPRSS2-ERG increases bone tropism of PCa cells and metastasis development.

Identification of four alternatively spliced transcripts of the Ucma/GRP gene, encoding a new Gla-containing protein.

The Ucma protein (Upper zone of growth plate and cartilage matrix associated protein) has recently been described as a novel secretory protein mainly expressed in cartilage and also as a novel vitamin-K-dependent protein named GRP (Gla-rich protein). This protein has the highest Gla content of any protein known to date. In this article, we identify four alternatively spliced variants of Ucma/GRP gene transcripts in mouse chondrocytes. We show that the expression of all four isoforms is associated with the early stages of chondrogenesis. The Ucma/GRP gene encodes four proteins named Ucma/GRP-F1, -F2, -F3, and -F4, which differ by exon 2, exon 4, or both. Among them, only Ucma/GRP-F1 and -F3 were secreted into the culture medium of transfected chondrocytes, while Ucma/GRP-F2 and -F4 accumulated in the cells. Using HeLa cells or freshly isolated embryonic mouse chondrocytes transfected with enhanced green fluorescent protein fusions, microscopy analysis revealed that Ucma/GRP-F1 and -F3 were localized in the Golgi complex, whereas Ucma/GRP-F2 and -F4 formed aggregates. This aggregation was microtubule-dependent since disruption of microtubules with nocodazole reduced Ucma/GRP-F2 and -F4 aggregation in a reversible manner. Using biochemical fractionation and Western blot analysis, Ucma/GRP-F1 and -F3 isoforms were detected in the soluble fraction while Ucma/GRP-F2 and -F4 were found in an insoluble-enriched fraction. We conclude that the co-expression of soluble and insoluble isoforms also Gla-rich and Gla-deleted isoforms may be finely tuned. Imbalance in isoform expression may therefore be involved in skeletal pathology.