MiR-378a inhibits glucose metabolism by suppressing GLUT1 in prostate cancer.

Prostate cancer (PCa) is the fifth leading cause of cancer related deaths worldwide, in part due to a lack of molecular stratification tools that can distinguish primary tumours that will remain indolent from those that will metastasise. Amongst potential molecular biomarkers, microRNAs (miRs) have attracted particular interest because of their high stability in body fluids and fixed tissues. These small non-coding RNAs modulate several physiological and pathological processes, including cancer progression. Herein we explore the prognostic potential and the functional role of miRs in localised PCa and their relation to nodal metastasis. We define a 7-miR signature that is associated with poor survival independently of age, Gleason score, pathological T state, N stage and surgical margin status and that is also prognostic for disease-free survival in patients with intermediate-risk localised disease. Within our 7-miR signature, we show that miR-378a-3p (hereafter miR-378a) levels are low in primary tumours compared to benign prostate tissue, and also lower in Gleason score 8-9 compared to Gleason 6-7 PCa. We demonstrate that miR-378a impairs glucose metabolism and reduces proliferation in PCa cells through independent mechanisms, and we identify glucose transporter 1 (GLUT1) messenger RNA as a direct target of miR-378a. We show that GLUT1 inhibition hampers glycolysis, leading to cell death. Our data provides a rational for a new PCa stratification strategy based on miR expression, and it reveals that miR-378a and GLUT1 are potential therapeutic targets in highly aggressive glycolytic PCa.

C-Met/miR-130b axis as novel mechanism and biomarker for castration resistance state acquisition.

Although a significant subset of prostate tumors remain indolent during the entire life, the advanced forms are still one of the leading cause of cancer-related death. There are not reliable markers distinguishing indolent from aggressive forms. Here we highlighted a new molecular circuitry involving microRNA and coding genes promoting cancer progression and castration resistance. Our preclinical and clinical data demonstrated that c-Met activation increases miR-130b levels, inhibits androgen receptor expression, promotes cancer spreading and resistance to hormone ablation therapy. The relevance of these findings was confirmed on patients' samples and by in silico analysis on an independent patient cohort from Taylor's platform. Data suggest c-Met/miR-130b axis as a new prognostic marker for patients' risk assessment and as an indicator of therapy resistance. Our results propose new biomarkers for therapy decision-making in all phases of the pathology. Data may help identify high-risk patients to be treated with adjuvant therapy together with alternative cure for castration-resistant forms while facilitating the identification of possible patients candidates for anti-Met therapy. In addition, we demonstrated that it is possible to evaluate Met/miR-130b axis expression in exosomes isolated from peripheral blood of surgery candidates and advanced patients offering a new non-invasive tool for active surveillance and therapy monitoring.

A microRNA code for prostate cancer metastasis.

Although the development of bone metastasis is a major detrimental event in prostate cancer, the molecular mechanisms responsible for bone homing and destruction remain largely unknown. Here we show that loss of miR-15 and miR-16 in cooperation with increased miR-21 expression promote prostate cancer spreading and bone lesions. This combination of microRNA endows bone-metastatic potential to prostate cancer cells. Concomitant loss of miR-15/miR-16 and gain of miR-21 aberrantly activate TGF-ß and Hedgehog signaling, that mediate local invasion, distant bone marrow colonization and osteolysis by prostate cancer cells. These findings establish a new molecular circuitry for prostate cancer metastasis that was validated in patients' cohorts. Our data indicate a network of biomarkers and druggable pathways to improve patient treatment.

BTG2 loss and miR-21 upregulation contribute to prostate cell transformation by inducing luminal markers expression and epithelial-mesenchymal transition.

Prostate cancer is one of the leading causes of cancer-related death in men. Despite significant advances in prostate cancer diagnosis and management, the molecular events involved in the transformation of normal prostate cells into cancer cells have not been fully understood. It is generally accepted that prostate cancer derives from the basal compartment while expressing luminal markers. We investigated whether downregulation of the basal protein B-cell translocation gene 2 (BTG2) is implicated in prostate cancer transformation and progression. Here we show that BTG2 loss can shift normal prostate basal cells towards luminal markers expression, a phenotype also accompanied by the appearance of epithelial-mesenchymal transition (EMT) traits. We also show that the overexpression of microRNA (miR)-21 suppresses BTG2 levels and promotes the acquisition of luminal markers and EMT in prostate cells. Furthermore, by using an innovative lentiviral vector able to compete with endogenous mRNA through the overexpression of the 3'-untranslated region of BTG2, we demonstrate that in prostate tumor cells, the levels of luminal and EMT markers can be reduced by derepression of BTG2 from microRNA-mediated control. Finally, we show that the loss of BTG2 expression confers to non-tumorigenic prostate cells ability to grow in an orthotopic murine model, thus demonstrating the central role of BTG2 downregulaton in prostate cancer biology.

Novel and selective calcitonin-inducing agents.

A series of xanthine sulfonamides is presented as a class of calcitonin (CT) inducers - a potentially new method for treating diseases associated with postmenopausal bone loss such as osteoporosis. We have found that certain di-n-butylxanthine sulfonamides 4 upregulate CT transcription in a CT-luciferase reporter gene assay (CT-luci) and increase the production and release of CT in a CT secretion/RIA assay (CTS). In addition, these compounds do not have potent PDE4 inhibitory activity as do the related xanthine methylene ketones such as denbufyllene (2). One compound in particular (9) shows a transcription activation ratio (TAR) of 2.1 in CT-luci, a CTS increase of 3.6-fold, and a PDE4 (phosphodiesterase type IV) IC(50) = 4.1 microM. In addition, this compound showed a statistically significant 47% trabecular bone protection in ovariectomized-induced osteopenia (OVX) rats as determined by assay when administered for 4 weeks at 30 mg/kg/day, i. p. by quantitative computed tomography (QCT). When administered p.o., compound 9 shows 50% trabecular bone protection when administered for 3 weeks at 50 mg/kg/day, i.p. This compared with salmon CT which shows 62% trabecular bone protection when administered at 50 IU/kg/day for 4 weeks.

The integrin specificity of human recombinant osteopontin.

The ability of full-length human recombinant osteopontin (OPN) to support the adhesion of various alphav integrin-expressing cell lines was determined in order to characterize its integrin selectivity. The identity of this protein was assessed by cDNA sequence and mass spectroscopic analysis, and confirmed as full-length OPN. Neither the human embryonic kidney 293 cell line, which expresses the alphavbeta1 integrin, nor the human colonic adenocarcinoma HT-29 cell line, which expresses the alphavbeta5 integrin, were able to adhere to OPN; both of these cell lines are deficient in the beta3 subunit. In contrast, an alphavbeta3 integrin-expressing cell line, SK-MEL-24, was able to adhere to OPN in an arginine-glycine-aspartic acid dependent manner. In addition, this OPN-mediated cellular adhesion was completely blocked with an anti-alphavbeta3 integrin antibody (LM609), confirming that only the alphavbeta3 integrin mediated this cellular adhesion. These data demonstrate that, at least among the alphav integrins, only the alphavbeta3 is able to support cellular adhesion to osteopontin. This finding may have implications for the design of therapeutics targeting OPN-integrin interactions.