LARP1 post-transcriptionally regulates mTOR and contributes to cancer progression.

RNA-binding proteins (RBPs) bind to and post-transcriptionally regulate the stability of mRNAs. La-related protein 1 (LARP1) is a conserved RBP that interacts with poly-A-binding protein and is known to regulate 5'-terminal oligopyrimidine tract (TOP) mRNA translation. Here, we show that LARP1 is complexed to 3000 mRNAs enriched for cancer pathways. A prominent member of the LARP1 interactome is mTOR whose mRNA transcript is stabilized by LARP1. At a functional level, we show that LARP1 promotes cell migration, invasion, anchorage-independent growth and in vivo tumorigenesis. Furthermore, we show that LARP1 expression is elevated in epithelial cancers such as cervical and non-small cell lung cancers, where its expression correlates with disease progression and adverse prognosis, respectively. We therefore conclude that, through the post-transcriptional regulation of genes such as mTOR within cancer pathways, LARP1 contributes to cancer progression.

Endo180 modulation by bisphosphonates and diagnostic accuracy in metastatic breast cancer.

BACKGROUND: Endo180 (CD280; MRC2; uPARAP)-dependent collagen remodelling is dysregulated in primary tumours and bone metastasis. Here, we confirm the release and diagnostic accuracy of soluble Endo180 for diagnosing metastasis in breast cancer (BCa). METHODS: Endo180 was quantified in BCa cell conditioned medium and plasma from BCa patients stratified according to disease status and bisphosphonate treatment (n=88). All P-values are from two-sided tests. RESULTS: Endo180 is released by ectodomain shedding from the surface of MCF-7 and MDA-MB-231 BCa cell lines. Plasma Endo180 was significantly higher in recurrent/metastatic (1.71±0.87; n=59) vs early/localised (0.92±0.37; n=29) BCa (P<0.0001). True/false-positive rates for metastasis classification were: 85%/50% for the reference standard, CA 15-3 antigen (28 U ml(-1)); ≤97%/≥36% for Endo180; and ≤97%/≥32% for CA 15-3 antigen+Endo180. Bisphosphonate treatment was associated with reduced Endo180 levels in BCa patients with bone metastasis (P=0.011; n=42). True/false-positive rates in bisphosphonate-naive patients (n=57) were: 68%/45% for CA 15-3 antigen; ≤95%/≥20% for Endo180; and ≤92%/≥21% for CA 15-3 antigen+Endo180. CONCLUSION: Endo180 is a potential marker modulated by bisphosphonates in metastatic BCa.

Circulating sphingosine-1-phosphate and erythrocyte sphingosine kinase-1 activity as novel biomarkers for early prostate cancer detection.

BACKGROUND: Current markers available for screening normal populations and for monitoring prostate cancer (PCa) treatment lack sensitivity and selectivity. Sphingosine-1-phosphate (S1P) is a circulating lipid second messenger involved in cell growth and migration, the immune response, angiogenesis, and malignant transformation. METHODS: Eighty-eight patients with localised, locally advanced, or metastatic PCa were recruited into this prospective single-centre study. Plasma S1P levels were measured and compared with age-matched controls with benign prostate hyperplasia (BPH) (n=110) or with young healthy males with the very small chance of having PCa foci (n=20). RESULTS: Levels of circulating S1P were significantly higher in healthy subjects (10.36 ± 0.69 pmol per mg protein, P<0.0001) and patients with BPH (9.39 ± 0.75, P=0.0013) than in patients with PCa (6.89 ± 0.58, ANOVA, P=0.0019). Circulating S1P levels were an early marker of PCa progression to hormonal unresponsiveness and correlated with prostate-specific antigen (PSA) levels and lymph node metastasis. During the course of the study, nine patients have died of PCa. Importantly, their circulating S1P levels were significantly lower (5.11 ± 0.75) than in the surviving patients (7.02 ± 0.22, n=79, P=0.0439). Our data suggest that the decrease in circulating S1P during PCa progression may stem from a highly significant downregulation of erythrocyte sphingosine kinase-1 (SphK1) activity (2.14 ± 0.17 pmol per mg protein per minute in PCa patients vs 4.7 ± 0.42 in healthy individuals, P<0.0001), which may be a potential mechanism of cancer-induced anaemia. CONCLUSION: This current study has provided a potential mechanism for cancer-related anaemia and the first evidence that plasma S1P and erythrocyte SphK1 activity are the potential markers for the diagnosis, monitoring, and predicating for PCa mortality.

Interventions to reduce harm associated with adolescent substance use.

A major proportion of the disease burden and deaths for young people in developed nations is attributable to misuse of alcohol and illicit drugs. Patterns of substance use established in adolescence are quite stable and predict chronic patterns of use, mortality, and morbidity later in life. We integrated findings of systematic reviews to summarise evidence for interventions aimed at prevention and reduction of harms related to adolescent substance use. Evidence of efficacy was available for developmental prevention interventions that aim to prevent onset of harmful patterns in settings such as vulnerable families, schools, and communities, and universal strategies to reduce attractiveness of substance use. Regulatory interventions aim to increase perceived costs and reduce availability and accessibility of substances. Increasing price, restricting settings of use, and raising legal purchase age are effective in reducing use of alcohol and tobacco and related harms. Screening and brief intervention are efficacious, but efficacy of a range of treatment approaches has not been reliably established. Harm-reduction interventions are effective in young people involved in risky and injecting substance use.

Fibrin monomer and fibrinopeptide B act additively to increase DNA synthesis in smooth muscle cells cultured from human saphenous vein.

PURPOSE: We investigated the hypothesis that fibrinogen increased DNA synthesis (and cell proliferation) of smooth muscle cells (SMCs) cultured from human saphenous vein and that the increased DNA synthesis was attenuated when cells were cultured on polymeric collagen. METHODS: SMCs were cultured from human saphenous vein on plastic, fibronectin, monomeric, and polymeric collagen. Fibrinogen products were prepared by proteolytic digestion. DNA synthesis was measured by bromodeoxyuridine incorporation into DNA, cell proliferation by cell counting, cyclic adenosine monophosphate by enzyme-linked immunosorbent assay, and fibrinopeptide B labeled with iodine 125 used for binding studies. RESULTS: Fibrin monomer (0.003-0.1 micromol/L) stimulated a concentration-dependent increase in DNA synthesis of up to 10-fold, which could be inhibited by the peptide Bbeta15-42. The stimulation of DNA synthesis was highest for cells cultured on plastic and lowest for cells cultured on type I collagen polymer. Much higher concentrations of fibrinogen (0.3-1 micromol/L) were required to effect similar increases in DNA synthesis. Fibrinogen had a particular effect to augment DNA synthesis, up to 14-fold, when cells were cultured on monomeric type I collagen. This augmented DNA synthesis was inhibited by a neutralizing antibody to urokinase-type plasminogen activator. Incubation of cells cultured on collagen monomer with fibrinogen resulted in production of fibrinopeptide B. Fibrinopeptide B (5 micromol/L) increased DNA synthesis by fourfold and had additive effects with fibrin monomer to increase DNA synthesis. Iodinated tyrosine fibrinopeptide B bound to SMCs (dissociation constant 0.6 micromol/L). CONCLUSION: Cultured human saphenous vein SMCs appear to have high-affinity receptors for fibrin monomer and fibrinopeptide B, the engagement of which stimulates DNA synthesis. These mechanisms may be pertinent to the association between fibrinogen and vein graft stenosis in vivo.

Urine antibody tests: new insights into the dynamics of HIV-1 infection.

BACKGROUND: Noninvasive methodologies provide alternatives to diagnostic blood tests and have high patient acceptance, increased safety, and reduced costs. Such tests may supplement or replace blood diagnostic assays currently in use. METHODS: Using a licensed urine-based test for antibody to HIV-1, we performed 25 991 HIV-1 urine antibody enzyme immunoassay (EIA) screening tests [confirmable by HIV-1 Western blot (WB)] on paired urine and blood specimens obtained from high- and low-risk HIV-1 subjects collected at six sites representative of the US population. RESULTS: Using HIV-1 urine EIA tests confirmed by urine Western blot, a compartmentalized immune response (urine positive/serum negative) occurred in 0.24% of a cohort of 11 896 subjects. In the same cohort, specimens that were urine negative/serum positive occurred in 0.17% of subjects. In a second study of 25 991 subjects that included 859 high-risk individuals, the false-positive urine EIA frequency (urine WB negative or indeterminate) was 1.3%. This false-positive frequency in the high-risk cohort was attributed, in part, to an IgA antibody response. We tabulated urine and serum indeterminate reactivities and examined their possible causes. Data are presented showing that antibodies from a seroindeterminate HIV-1vau group O subject were reactive in urine EIA and urine WB tests. An analysis of the HIV-1vau strain group O env nucleotide sequence disclosed a high frequency of homology with human chromosome 7q31, a fragile site implicated in many human malignancies. CONCLUSIONS: These results demonstrate the utility of urine for alternative HIV-1 antibody testing and provide new insights into the pathogenesis of HIV-1 infection and into potential application of this approach in investigation of other microbial pathogens and toxic compounds.

Evaluation of blood collected on filter paper for detection of antibodies to human immunodeficiency virus type 1.

This study was undertaken to evaluate the sensitivity and specificity of a commercial enzyme immunoassay in detecting antibody to human immunodeficiency virus type 1 using whole-blood specimens collected onto filter paper. Results obtained with specimens collected onto filter paper were comparable with those obtained with the corresponding serum or plasma specimens.

Induction of target antigens and conversion to susceptible phenotype of NK-cell-resistant lymphoid cell line.

Two autologous Herpesvirus papio producer lymphoid cell lines and one autologous non-producer line were compared for susceptibility to natural killer (NK) cell-mediated lysis. The non-producer cell line, 26CB-1, was more resistant to NK cell killing compared to one viral producer counterpart 13CB-1, but equally resistant when compared to another, 8CB-1. Treatment with chemical agents that affect differentiation or activate the viral cycle, including n-butyrate, IuDR, 5-azacytidine and tunicamycin, increased the susceptibility to killing of the non-producer line but had less effect on the 13CB-1 producer line. The increase in susceptibility was due to induction of new target antigens: activated 26CB-1 cells were more effective at inhibiting NK-cell-mediated lysis and were bound by more NK cells than untreated control cells. The expression of NK target structures may be related to the differentiated state rather than to the viral production status to target cells.

Phylogeny of NK cell reactivity against human and nonhuman primate lymphoblastoid cell lines: evolving and conserved target antigens.

Both human and nonhuman primate natural killer (NK) cells display little or no killing against allogeneic B lymphoblastoid cell lines. However, the same B cell lines are killed in baboon-human (B alpha H) or human-baboon (H alpha B) xenogeneic combinations. Competition-inhibition experiments indicate that the xenogeneic determinants recognized by NK cells are found principally if not exclusively on B rather than T target cells. Cell lines from closely related chimpanzee or orang-utan species can block some killing of human target cells, but lines from more distantly related species including gibbon, macaque, baboon, and marmoset do not inhibit cytotoxicity. This suggests that some NK target structures are susceptible to evolutionary change. Gibbon or marmoset lines infected with Epstein Barr virus (EBV) do not block killing, suggesting that host rather than viral determinants are being recognized. In contrast to the foregoing pattern, 2 cell lines derived from the same baboon differed in susceptibility to NK lysis irrespective of the effector cell species. The viral producer line 13CB-1 was more susceptible to lysis than its viral nonproducer partner 26CB-1. Thus, some NK target antigens may be highly conserved whereas others evolve with the species.