Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multiple myeloma (MM) develops devastating bone destruction with enhanced bone resorption and suppressed bone formation. In contrast to enhanced osteoclastogenesis, little is known about the mechanism of impaired bone formation in MM. Because a canonical Wingless-type (Wnt) signaling pathway has recently been shown to play an important role in osteoblast differentiation, we examined whether MM cells affect a canonical Wnt pathway to suppress bone formation. Conditioned media from RPMI8226 and U266 MM cell lines and primary MM cells suppressed in vitro mineralization as well as alkaline phosphatase activity in osteoblasts induced by bone morphogenetic protein 2 (BMP-2). These cell lines constitutively produced a soluble Wnt inhibitor, secreted Frizzled-related protein 2 (sFRP-2), but not other Wnt inhibitors including sFRP-1, sFRP-3, and dickkopf 1 (DKK-1) at the protein level. Most MM cells from patients with advanced bone destructive lesions also expressed sFRP-2. Furthermore, exogenous sFRP-2 suppressed osteoblast differentiation induced by BMP-2, and immunodepletion of sFRP-2 significantly restored mineralized nodule formation in vitro, suggesting a predominant role for MM cell-derived sFRP-2 in the impairment of bone formation by MM. Thus, in addition to enhanced osteolysis, MM cells also suppress bone formation at least in part through an inhibition of the canonical Wnt pathway by secreting sFRP-2.
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PMID:Myeloma cells suppress bone formation by secreting a soluble Wnt inhibitor, sFRP-2. 1603 Jan 94

Secreted frizzled-related proteins (sFRPs) are modulators of Wnt signaling. This study was undertaken for definitive assessment of contribution of different sFRPs in osteoblastic differentiation of mesenchymal progenitor cells and apoptosis of osteoblasts. Treatment of C3H10T1/2 cells with sFRP-2 at concentrations of 10, 50, and 100nM and sFRP-4 at low concentrations (5nM) significantly increased Wnt-3A-induced alkaline phosphatase (ALP) activities, whereas sFRP-1 or 3 did not. Retroviral transduction of the sFRP-2 but not other sFRPs also significantly enhanced ALP activity induced by beta-glycerophosphate and ascorbic acid. Furthermore, transfection of all the sFRP expression vectors significantly increased beta-catenin/TCF reporter activity and the effects were most prominent with sFRP-2 and -4. In osteoblast apoptosis assay, only sFRP-3 increased etoposide-induced apoptosis in MC3T3-E1 mouse osteoblasts. In conclusion, we found that different repertoires of sFRPs exert differential effects on osteoblastic differentiation of mouse mesenchymal cells and cellular apoptosis of mouse osteoblasts in vitro.
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PMID:Differential effects of secreted frizzled-related proteins (sFRPs) on osteoblastic differentiation of mouse mesenchymal cells and apoptosis of osteoblasts. 1816 53