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The dynamic balance between bone formation and bone resorption is vital for the retention of bone mass. The abnormal activation of osteoclasts, unique cells that degrade the bone matrix, may result in many bone diseases such as osteoporosis. Osteoporosis, a bone metabolism disease, occurs when extreme osteoclast‐mediated bone resorption outstrips osteoblast‐related bone synthesis. Therefore, it is of great interest to identify agents that can regulate the activity of osteoclasts and prevent bone loss‐induced bone diseases. In this study, we found that N‐[2‐(4‐benzoyl‐1‐piperazinyl)phenyl]‐2‐(4‐chlorophenoxy) acetamide (PPOAC‐Bz) exerted a strong inhibitory effect on osteoclastogenesis. PPOAC‐Bz altered the mRNA expressions of several osteoclast‐specific marker genes and blocked the formation of mature osteoclasts, suppressing F‐actin belt formation and bone resorption activity in vitro. In addition, PPOAC‐Bz prevented OVX‐induced bone loss in vivo. These findings highlighted the potential of PPOAC‐Bz as a prospective drug for the treatment of osteolytic disorders. [ABSTRACT FROM AUTHOR]

G protein‐coupled receptor 119 (GPR119) is known to be a promising therapeutic target for type 2 diabetes. Recently, it has been reported that the GPR119 agonist increases bone mineral density in an animal model of diabetes, suggesting that GPR119 may play a key role in bone metabolism. In this study, we investigated the functional role of GPR119 in receptor activator of nuclear factor‐κB ligand (RANKL)‐induced osteoclast formation. We found that the GPR119 expression was markedly increased in preosteoclasts and then downregulated in mature osteoclasts. Activation of GPR119 with AS1269574, a potent selective agonist for GPR119, inhibited the generation of multinuclear osteoclasts from bone marrow‐derived macrophages. Confirming this observation, targeted silencing of GPR119 using short hairpin RNA abrogated the AS1269574‐mediated suppressive effect on osteoclast formation. GPR119 activation attenuated the expression of c‐Fos and nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and blocked RANKL‐stimulated phosphorylation of IκBα, c‐Jun N‐terminal protein kinase (JNK), and extracellular signal‐regulated kinase (ERK) but not p38. In addition, GPR119 activation suppressed preosteoclast fusion by downregulating the expression of the dendritic cell‐specific transmembrane (DC‐STAMP), a molecule that is essential for cell–cell fusion in osteoclast formation. Furthermore, ectopic expression of DC‐STAMP restored AS1269574‐mediated inhibition of osteoclast fusion. Taken together, our findings demonstrate that GPR119 plays a negative role in osteoclast differentiation and fusion induced by RANKL, and therefore may represent a potential target for bone resorption‐associated diseases. G protein‐coupled receptor 119 (GPR119) activation inhibits osteoclastogenesis and fusion induced by receptor activator of nuclear factor‐κB ligand (RANKL). GPR119 may become a new target for the treatment of bone‐erosive diseases characterized by increased osteoclast number. [ABSTRACT FROM AUTHOR]

Core binding factor β (Cbfβ) is a partner protein of Runx family transcription factors with minimally characterized function in cartilage. Here we address the role of Cbfβ in cartilage by generating chondrocyte-specific Cbfβ-deficient mice ( CbfbΔch/Δch) from Cbfb-floxed mice crossed with mice expressing Cre from the Col2a1 promoter. CbfbΔch/Δch mice died soon after birth and exhibited delayed endochondral bone formation, shorter appendicular skeleton length with increased proliferative chondrocytes, and nearly absent hypertrophic chondrocyte zones. Immunohistochemical and quantitative real-time PCR analyses showed that the number and size of proliferative chondrocytes increased and the expression of chondrocyte maturation markers at the growth plates, including Runx2, osterix, and osteopontin, significantly diminished in CbfbΔch/Δch mice compared to wild type mice. With regard to signaling pathways, both PTHrP-Ihh and BMP signaling were compromised in CbfbΔch/Δch mice. Mechanistically, Cbfβ deficiency in chondrocytes caused a decrease of protein levels of Runx transcription factors by accelerating polyubiquitination-mediated proteosomal degradation in vitro. Indeed, Runx2 and Runx3, but not Runx1, decreased in CbfbΔch/Δch mice. Collectively, these findings indicate that Cbfβ plays a critical role for chondrocyte differentiation through stabilizing Runx2 and Runx3 proteins in cartilage J. Cell. Physiol. 230: 162-171, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Carboplatin, an advanced anticancer drug with excellent efficacy against ovarian cancer, was developed to alleviate the side effects that often occur with cisplatin and other platinum-based compounds. Our study reports the in vitro characteristics, viability, and activity of cells expressing the inducible nitric oxide synthase (iNOS) gene after carboplatin was conjugated with polysuccinimide (PSI) and administered in combination with other widely used anticancer drugs. PSI, which has promising properties as a drug delivery material, could provide a platform for prolonging carboplatin release, regulating its dosage, and improving its side effects. The iNOS gene has been shown to play an important role in both cancer cell survival and inhibition. Herein, we synthesized a PSI-carboplatin conjugate to create a modified anticancer agent and confirmed its successful conjugation. To ensure its solubility in water, we further modified the structure of the PSI-carboplatin conjugate with 2-aminoethanol groups. To validate its biological characteristics, the ovarian cancer cell line SKOV-3 and normal ovarian Chinese hamster ovary cells were treated with the PSI-carboplatin conjugate alone and in combination with paclitaxel and topotecan, both of which are used in conventional chemotherapy. Notably, PSI-carboplatin conjugation can be used to predict changes in the genes involved in cancer growth and inhibition. In conclusion, combination treatment with the newly synthesized polymer-carboplatin conjugate and paclitaxel displayed anticancer activity against ovarian cancer cells but was not toxic to normal ovarian cancer cells, resulting in the development of an effective candidate anticancer drug without severe side effects.