Clin Cancer Res
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Comparative Study
Phosphorylation of the 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase/PFKFB3 family of glycolytic regulators in human cancer.
Fructose 2,6-bisphosphate (F2,6BP) is a potent activator of phosphofructokinase, which is a rate-limiting enzyme of glycolysis. The concentration of F2,6BP depends on the activity of the bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase). Four genes encoding PFK-2/FBPase have been identified and termed PFKFB1 to PFKFB4. PFKFB3 protein is expressed in high levels in human tumors in situ. The purpose of this study was to determine the role of functional interactions between the phosphorylation of PFKFB3 and activated glycolysis in human cancer cells. ⋯ These findings support a potential role for the phosphorylation of PFKFB3 protein in the progression of cancer and angiogenesis.
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Pseudolaric acid B (PAB) is the major bioactive constituent in the root bark of Pseudolarix kaempferi that has been used as an antifungal remedy in traditional Chinese medicine. Previous studies showed that PAB exhibited substantial cytotoxicity. The aims of this study were to elucidate the molecular target of PAB, to examine its mechanism of action, and to evaluate the efficacy of this compound in vivo. ⋯ We identified the microtubules as the molecular target of PAB. Furthermore, we showed that PAB circumvents P-glycoprotein overexpression-induced drug resistance and is effective in inhibiting tumor growth in vivo. Our work will facilitate the future development of PAB as a cancer therapeutic.
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To present the basis of the decision of the Food and Drug Administration to grant accelerated approval for letrozole for extended adjuvant treatment of early-stage breast cancer in postmenopausal women after completion of adjuvant tamoxifen. ⋯ Letrozole administration led to a statistically significant prolongation in disease-free survival. Fractures and cardiovascular events were similar to placebo; however, new diagnoses of osteoporosis were more frequent. Short duration of treatment and follow-up precluded assessment of long-term safety and efficacy. Thus, accelerated approval was granted instead of regular approval.