Sprouty1, a new target of the angiostatic agent 16K prolactin, negatively regulates angiogenesis

BACKGROUND:Disorganized angiogenesis is associated with several pathologies, including cancer. The identification of new genes that control tumor neovascularization can provide novel insights for future anti-cancer therapies. Sprouty1 (SPRY1), an inhibitor of the MAPK pathway, might be one of these new genes. We identified SPRY1 by comparing the transcriptomes of untreated endothelial cells with those of endothelial cells treated by the angiostatic agent 16K prolactin (16K hPRL). In the present study, we aimed to explore the potential function of SPRY1 in angiogenesis.RESULTS:We confirmed 16K hPRL induced up-regulation of SPRY1 in primary endothelial cells. In addition, we demonstrated the positive SPRY1 regulation in a chimeric mouse model of human colon carcinoma in which 16K hPRL treatment was shown to delay tumor growth. Expression profiling by qRT-PCR with species-specific primers revealed that induction of SPRY1 expression by 16K hPRL occurs only in the (murine) endothelial compartment and not in the (human) tumor compartment. The regulation of SPRY1 expression was NF-kappaB dependent. Partial SPRY1 knockdown by RNA interference protected endothelial cells from apoptosis as well as increased endothelial cell proliferation, migration, capillary network formation, and adhesion to extracellular matrix proteins. SPRY1 knockdown was also shown to affect the expression of cyclinD1 and p21 both involved in cell-cycle regulation. These findings are discussed in relation to the role of SPRY1 as an inhibitor of ERK/MAPK signaling and to a possible explanation of its effect on cell proliferation.CONCLUSIONS:Taken together, these results suggest that SPRY1 is an endogenous angiogenesis inhibitor

MicroRNA-21 Exhibits Antiangiogenic Function by Targeting RhoB Expression in Endothelial Cells

BACKGROUND: MicroRNAs (miRNAs) are endogenously expressed small non-coding RNAs that regulate gene expression at post-transcriptional level. The recent discovery of the involvement of these RNAs in the control of angiogenesis renders them very attractive in the development of new approaches for restoring the angiogenic balance. Whereas miRNA-21 has been demonstrated to be highly expressed in endothelial cells, the potential function of this miRNA in angiogenesis has never been investigated. METHODOLOGY/PRINCIPAL FINDINGS: We first observed in endothelial cells a negative regulation of miR-21 expression by serum and bFGF, two pro-angiogenic factors. Then using in vitro angiogenic assays, we observed that miR-21 acts as a negative modulator of angiogenesis. miR-21 overexpression reduced endothelial cell proliferation, migration and the ability of these cells to form tubes whereas miR-21 inhibition using a LNA-anti-miR led to opposite effects. Expression of miR-21 in endothelial cells also led to a reduction in the organization of actin into stress fibers, which may explain the decrease in cell migration. Further mechanistic studies showed that miR-21 targets RhoB, as revealed by a decrease in RhoB expression and activity in miR-21 overexpressing cells. RhoB silencing impairs endothelial cell migration and tubulogenesis, thus providing a possible mechanism for miR-21 to inhibit angiogenesis. Finally, the therapeutic potential of miR-21 as an angiogenesis inhibitor was demonstrated in vivo in a mouse model of choroidal neovascularization. CONCLUSIONS/SIGNIFICANCE: Our results identify miR-21 as a new angiogenesis inhibitor and suggest that inhibition of cell migration and tubulogenesis is mediated through repression of RhoB

Subnormal growth during puberty in children treated for acute lymphoblastic leukemia.

Growth was studied longitudinally in 19 children who were long-term survivors after acute lymphoblastic leukemia (ALL). Of the children, 13 were girls; 6 were boys. They had all undergone a 3-year cytostatic treatment period which included vincristine, adriamycin, asparaginase, methotrexate, purinethol, and prednisone. Prophylactic cerebral irradiation (20-24 Gy) had been given to all children; 4 of them had also been given irradiation to the spine (10 Gy). The pattern of growth was nearly identical in girls and boys. Growth in relation to the therapy was almost normal, whereas growth during puberty was subnormal and final height was 1.3 SD less than expected at onset of disease. The growth pattern was the same for children with cerebrospinal irradiation as for those with cerebral irradiation. In view of the present results and previous studies on growth hormone (GH) secretion after cerebral irradiation, we suggest that treatment with luteinizing hormone releasing hormone (LHRH) or GH could be considered at puberty for children who have been treated for ALL, including cerebral irradiation, and who have a poor prognosis for final height

First-trimester diagnosis of conjoined twins

Two cases of conjoined twins were diagnosed during first-trimester endovaginal ultrasound and were confirmed by embryoscopy performed prior to the termination of pregnancy. An early and accurate diagnosis of this anomaly, obtained by the combined use of ultrasound and endoscopy, may enable adequate counselling and an earlier termination of pregnancy associated with minimal maternal risks