The anti-tumor agent sagopilone shows antiresorptive effects both in vitro and in vivo

Site-Specific Fracture Healing: Comparison between Diaphysis and Metaphysis in the Mouse Long Bone

The process of fracture healing varies depending upon internal and external factors, such as the fracture site, mode of injury, and mechanical environment. This review focuses on site-specific fracture healing, particularly diaphyseal and metaphyseal healing in mouse long bones. Diaphyseal fractures heal by forming the periosteal and medullary callus, whereas metaphyseal fractures heal by forming the medullary callus. Bone healing in ovariectomized mice is accompanied by a decrease in the medullary callus formation both in the diaphysis and metaphysis. Administration of estrogen after fracture significantly recovers the decrease in diaphyseal healing but fails to recover the metaphyseal healing. Thus, the two bones show different osteogenic potentials after fracture in ovariectomized mice. This difference may be attributed to the heterogeneity of the skeletal stem cells (SSCs)/osteoblast progenitors of the two bones. The Hox genes that specify the patterning of the mammalian skeleton during embryogenesis are upregulated during the diaphyseal healing. Hox genes positively regulate the differentiation of osteoblasts from SSCs in vitro. During bone grafting, the SSCs in the donor’s bone express Hox with adaptability in the heterologous bone. These novel functions of the Hox genes are discussed herein with reference to the site-specificity of fracture healing.

Synthesis & antitumor activity of epothilones B and D and their analogs

Epothilone is a newly developed antitumor drug; its antitumor principle is to stop the cell cycle by binding to tubulin in tumor cells, promoting tubulin polymerization, inhibiting depolymerization of microtubules, and ultimately inducing apoptosis. There are many analogs of epothilone, such as epothilone B, epothilone D, ixabepilone, sagopilone, 21-amino-epothilone B and KOS-1584. Herein, the synthesis and antitumor activity of epothilones B and D were summed up. The antitumor activity of epothilone analogs was also compared. Synthesis of epothilone and its analogs is more complex, and choosing the proper synthetic method is very important. Moreover, these compounds have obvious antitumor effect. The epothilone and its analogs will continue to play an important role in the future treatment of tumors.