The cellular mechanism by which TNF-alpha inhibits osteoblastic differentiation induced by BMPs was investigated using mouse myoblast C2C12 cells expressing functional BMP receptors and Smad signaling molecules except ALK-6. Osteoblast transformation in response to BMP-2 was morphologically suppressed by TNF-alpha. Expression of biological markers for osteoblasts including Runx2 and osteocalcin, alkaline phosphatase activity, and parathyroid hormone (PTH) responsiveness shown by PTH-induced cAMP production were readily activated by BMP-2, -4, -6, and -7. The BMP-induced osteoblastic phenotype was dose-dependently inhibited by TNF-alpha. BMP-induced Smad1,5,8 phosphorylation of C2C12 cells was suppressed by TNF-alpha signaling. In addition, cDNA array analysis showed an increased expression of inhibitory Smad6 by TNF-alpha. MAP kinase analysis showed that ERK1/ERK2 and SAPK/JNK phosphorylation were selectively activated by TNF-alpha regardless of the presence of BMP ligands. BMPs had no effect on expression levels of TNF type 1 and 2 receptors. Notably, inhibition of SAPK/JNK restored TNF-alpha effects on BMP-induced osteoblast differentiation demonstrated by Id-1-promoter activity as well as Runx2 and osteocalcin mRNA levels. Collectively, TNF-alpha elicits BMP-induced osteogenic inhibition by suppressing BMP-Smad signaling pathway, at least in part, through SAPK/JNK activation and Smad6 upregulation.
Context. Although opioids and pregabalin are widely used for cancer-related neuropathic pain (CNP), no clinical trials exist to determine which medications are effective when an opioid-pregabalin combination therapy fails.Objectives. We investigated the efficacy of duloxetine for CNP nonresponsive or intolerant to opioid-pregabalin combination therapy.Methods. A multicenter, randomized, double-blind, placebo-controlled trial was performed at 12 specialized palliative care services in Japan. Patients with CNP average pain scores (Brief Pain Inventory [BPI]eItem 5) $ 4 in the previous 24 hours and nonresponsive or intolerant to opioid-pregabalin combination therapy were eligible. Patients with chemotherapy-induced peripheral neuropathies were excluded. Patients were administered duloxetine 20 mg/day titrated to 40 mg/day or placebo for 10 days. The primary endpoint was BPI-Item 5 on Day 10. Responder analysis measured proportions of patients with 30% and 50% pain decreases.Results. Seventy patients were enrolled. Complete case analysis revealed mean BPI-Item 5 on Day 10 of 4.03 for Group D vs. 4.88 for Group P (P ¼ 0.053). Baseline observation carried forward analysis revealed mean BPI-Item 5 on Day 10 of 4.06 and 4.91 for Groups D and P, respectively (P ¼ 0.048). Clinically meaningful pain improvement ($30%) was reported by 44.1% (n ¼ 15) of patients in Group D vs. 18.2% (n ¼ 6) in Group P (P ¼ 0.02); 32.4% (n ¼ 11) vs. 3.0% (n ¼ 1) of patients in Groups D and P, respectively, reported pain reduction $ 50% (P ¼ 0.002).Conclusion. Adding duloxetine to opioid-pregabalin therapy might have clinical benefit in alleviating refractory CNP. Further studies are needed to conclude the efficacy of adding duloxetine. J Pain Symptom
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.