Proline-Serine-Threonine Phosphatase-Interacting Protein 2 Alleviates Diabetes Mellitus-Osteoarthritis in Rats through Attenuating Synovial Inflammation and Cartilage Injury.

OBJECTIVE: To explore the possible way of proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2) influencing diabetes mellitus-osteoarthritis (DM-OA) progression. METHODS: In vivo, eight-week-old male Sprague Dawley rats were induced with DM-OA by intraperitoneal injection of streptozotocin with high-fat diet feeding and intra-articular injection of monoiodoacetate. PSTPIP2 overexpression was achieved by intra-articular injection of lentivirus vectors. PSTPIP2 expression was verified by real-time polymerase chain reaction and Western blotting. Histological changes were examined by hematoxylin/eosin and safranin-O/fast-green staining. In vitro, rat synovial fibroblasts were induced DM-OA by stimulation of high glucose (HG) and interleukin (IL)-1ß. PSTPIP2 overexpression was achieved by lentivirus infection. U0126 was added as an ERK inhibitor. Levels of tumor necrosis factor (TNF)-α, IL-6, and IL-1ß were detected using enzyme-linked immunosorbent assay. Expression of matrix metalloproteinase (MMP)-3, MMP-13, aggrecanase-2 (ADAMTS-5), intercellular cell adhesion molecule (ICAM)-1, extracellular regulated protein kinase (ERK) and phospho-ERK (p-ERK) was detected by Western blotting. RESULTS: In DM-OA rats, PSTPIP2 relative messenger RNA (mRNA) level was significantly decreased compared to control rats. The protein expression was also decreased obviously. Inflammation score in synovium was dramatically increased, accompanying with increased TNF-α, IL-6, and IL-1ß levels. Osteoarthritis research society international (OARSI) score in cartilage was markedly increased, along with increased MMP-3, MMP-13, ADAMTS-5, ICAM-1, ERK and p-ERK expression. In PSTPIP2-overexpressed DM-OA rats, PSTPIP2 mRNA level and protein expression was increased compared to DM-OA rats received negative-control lentivirus vectors. The inflammation score, as well as TNF-α, IL-6, and IL-1ß levels were dramatically decreased. Also, the OARSI score and protein expression of MMP-3, MMP-13, ADAMTS-5, ICAM-1, ERK and p-ERK were decreased. In HG+IL-1ß-treated rat synovial fibroblasts, PSTPIP2 protein expression was decreased compared to normal glucose (NG)-treated cells. Levels of TNF-α, IL-6, and IL-1ß, as well as expression of MMP-3, MMP-13, ADAMTS-5, ICAM-1, ERK and p-ERK were increased. After cells were infected with PSTPIP2-overexpressed lentivirus, levels of TNF-α, IL-6, and IL-1ß, and expression of MMP-3, MMP-13, ADAMTS-5, ICAM-1, ERK and p-ERK were obviously decreased compared to cells infected with NC lentivirus. In addition, ERK inhibitor U0126 treatment also decreased the TNF-α, IL-6, and IL-1ßlevels and MMP-3, MMP-13, ADAMTS-5, ICAM-1, ERK and p-ERK expression in HG + IL-1ß treated rat synovial fibroblasts. CONCLUSION: Overexpression of PSTPIP2 alleviates synovial inflammation and cartilage injury during DM-OA progression via inhibiting ERK phosphorylation.

Hypoxia-induced resistance to cisplatin-mediated apoptosis in osteosarcoma cells is reversed by gambogic acid independently of HIF-1α.

In vitro evidence of hypoxia-induced resistance to cisplatin (CDDP)-mediated apoptosis exists in human osteosarcoma (OS). Gambogic acid (GA) is a promising chemotherapeutic compound that could increase the chemotherapeutic effectiveness of CDDP in human OS cells by inducing cell cycle arrest and promoting apoptosis. This study examined whether GA could overcome OS cell resistance to CDDP. Hypoxia significantly reduced levels of CDDP-induced apoptosis in the OS cell lines MG63 and HOS. However, combined treatment with GA and CDDP revealed a strong synergistic action between these drugs, and higher protein levels of the apoptosis-related factor Fas, cleaved caspase-8 and cleaved caspase-3 and lower expression of hypoxia-inducible factor (HIF)-1α are detected in both cell lines. Meanwhile, drug resistance was not reversed by exposure to the HIF-1α inhibitor 2-methoxyestradiol. These findings strongly suggest that hypoxia-induced resistance to CDDP is reversed by GA in OS cells independently of HIF-1α. Furthermore, in vivo studies using xenograft mouse models revealed that combination therapy with CDDP and GA exerted increased antitumor effects by inducing apoptosis. Taken together, our results demonstrate that GA may be a new potent therapeutic agent useful for targeting human OS cells.

Matrine inhibits the growth and induces apoptosis of osteosarcoma cells in vitro by inactivating the Akt pathway.

Matrine, a natural product, has been demonstrated to be a promising chemotherapeutic drug for some cancers. Using flow cytometric analysis of the cell cycle and apoptosis, we found that matrine inhibited the proliferation and induced apoptosis in the human osteosarcoma (OS) cell lines MG63, HOS, U2OS, and SAOS2 in vitro in a dose-dependent manner. We therefore assessed the role of the serine/threonine kinase Akt in the regulation of matrine-mediated cell growth inhibition and apoptosis induction in human OS cell lines. After treatment for 48 h, matrine induced G0/G1-stage cell cycle arrest in MG63, U2OS, and SAOS2 cells associated with an increase in the expression of p27(Kip1) and a decrease in the expression of Akt, glycogen synthase kinase 3 (GSK3)-ß (Ser9), and cyclin D1. Furthermore, the pro-apoptotic factor Bax was upregulated. Overall, our findings suggest that matrine may be an effective anti-osteosarcoma drug due to its ability to inhibit proliferation and induce apoptosis in OS cells, possibly through the involvement of Akt signaling.

Viability inhibition effect of gambogic acid combined with cisplatin on osteosarcoma cells via mitochondria-independent apoptotic pathway.

We previously demonstrated that gambogic acid (GA) is a promising chemotherapeutic compound for human osteosarcoma treatment. The aim of this study was to detect whether the combination of lower-dose GA (0.3 mg/L) and cisplatin (CDDP) (1 mg/L) could perform a synergistic effect on inhibiting tumor in four osteosarcoma cell lines. Our results showed that the combination between GA at lower dose and CDDP significantly exerts a synergistic effect on inhibiting the cellular viability in MG63, HOS, and U2OS cells. In contrast, an antagonistic character was detected in SAOS2 cells exposed to the combined use of lower-dose GA (0.3 mg/L) and CDDP (1 mg/L). Then, analysis of cell cycle showed the combination of both drugs significantly induced the G2/M phase arrest, without any difference relative to GA treatment alone, in MG63 cells. Flow-cytometric analysis of cell apoptosis displayed that the apoptotic rate in the combination group is higher than that in GA treatment alone in MG63, HOS, and U2OS cells. The combined use of both drugs had no effect on mitochondrial membrane potential, but promoted the apoptosis-inducing function through triggering of CDDP in the three cell lines. By measurement of mitochondrial membrane potential, the activity of caspase-3 and the expressions of caspase-8 and caspase-9, it was showed that the apoptosis-promoting effect of the combined use of both drugs could be dependent on the death receptor apoptosis pathway, not dependent on the mitochondria apoptosis mechanism. This research, for the first time, demonstrates that GA could increase the chemotherapeutic effect of CDDP in human osteosarcoma treatment through inducing the cell cycle arrest and promoting cell apoptosis.

[Pilot-scale opposite folded plate hybrid anaerobic reactor (OFPHAR) in treatment of sewage].

Based on the theories of mass-transfer and two-double integrated staged multi-phase anaerobe (TSMPA), a pilot-scale opposite folded plate hybrid anaerobic reactor (OFPHAR) was designed to treat low concentration sewage. All the trial lasted 12 months and the results indicated that the optimal HRT was 6h. At this HRT, the COD, TP and TN removal rate were 78.58%, 35.15%, 39.17%, respectively, at 25 degrees C +/- 2 degrees C. The optimal rate of anaerobic section was 45%-65%. Controlled HRT = 6 h, the COD, TP and TN removal rate were 64.37%, 20.72%, 23.65%, respectively, and the specific methane production capacity were 1.85 mL/(g x h) when the temperature decreased to 7 degrees C. The results of trial indicated that apply this OFPHAR to treat low concentration sewage at low temperature in north China is feasible.