Reversal effect of BM-cyclin 1 on multidrug resistance by down-regulating MRP2 in BALB/C nude mice bearing C-A120 cells

Occlusal trauma inhibits osteoblast differentiation and bone formation through IKK-NF-κB signaling

BACKGROUND

Occlusal trauma is an important factor promoting bone loss caused by periodontal diseases. Although there are reports of traumatic force promoting bone resorption in periodontal diseases, no studies examining the inhibition of bone formation by traumatic force and the underlying mechanism have been reported. The aim of this study was to investigate the mechanism whereby traumatic force inhibits bone formation.

METHODS

MC3T3-E1 cells were induced to undergo osteogenic differentiation and subjected to cyclic uniaxial compressive stress with or without stimulation with Pg. LPS. The expression of osteoblast markers and the activation of IKK-NF-κB signaling were evaluated in vitro. Then, MC3T3-E1 cells were induced to undergo osteogenic differentiation and subjected to cyclic uniaxial compressive stress with or without IKK-2 Inhibitor VI. The expression of osteoblast markers was determined. Then, the classic Wnt signaling pathway (β-catenin, Gsk3β, p-Gsk3β, and Dkk1) was further evaluated in vitro. Finally, occlusal trauma was induced in Wistar rats with or without the injection of IKK-2 Inhibitor VI, to evaluate changes in bone mass and IKK-NF-κB and Wnt/β-catenin signaling in vivo.

RESULTS

After stimulation with Pg. LPS and traumatic force, IKK-NF-κB signaling was significantly activated in vitro. The expression of osteoblast markers and the activity of alkaline phosphatase in MC3T3-E1 cells declined after traumatic force loading and were rescued when IKK-NF-κB signaling was blocked. Wnt/β-catenin signaling was accordingly inhibited upon force loading, but this inhibition was reversed when IKK-NF-κB was antagonized in vitro. X-ray and Micro-CT analysis of the mandibles of the rats as well as HE and TRAP staining showed that bone loss induced by occlusal trauma declined after IKK-NF-κB was inhibited. The expression of p65 and IκBα was increased when occlusal trauma was induced in Wistar rats, whereas β-catenin, OCN, and Runx2 levels were decreased. After blocking IKK-NF-κB, significant upregulation of β-catenin, OCN, and Runx2 was observed in rats suffering from occlusal trauma.

CONCLUSIONS

IKK-NF-κB signaling could be activated by traumatic force or occlusal trauma. Its activation promoted the degradation of β-catenin, ultimately inhibiting osteogenic differentiation in vitro and bone formation in vivo.

DRP5 is involved in cancer cell growth and predicts poor prognosis in human osteosarcoma

Osteosarcoma is an extremely aggressive primary malignant bone tumor of childhood. Collapsin response mediator proteins (CRMPs), which are highly expressed in the developing nervous system, were recently shown to be associated with cancer development. However, the relationship between DRP5 (CRMP5) and osteosarcoma has not been evaluated. In this study, we investigated the role of DRP5 in the regulation of osteosarcoma growth. DRP5 mRNA and protein levels were significantly upregulated in human osteosarcoma cell lines and associated with increased migration and invasion. Genetic knockdown of DRP5 markedly suppressed the expression of matrix metalloproteinase (MMP)‐2 and MMP‐9. DRP5 silencing significantly inhibited osteosarcoma cell growth in vitro and in a xenograft mouse model in vivo. Microarray immunohistochemical analysis of osteosarcoma specimens and Kaplan–Meier analysis showed that patients with high DRP5 protein expression had shorter overall survival than those with low DRP5 levels. Taken together, these results suggest that DRP5 plays a critical role in the regulation of osteosarcoma and could be a potential therapeutic target and prognostic factor in osteosarcoma.

Inhibition of prostate cancer growth by solanine requires the suppression of cell cycle proteins and the activation of ROS/P38 signaling pathway

Solanine, a naturally steroidal glycoalkaloid in nightshade (Solanum nigrum Linn.), can inhibit proliferation and induce apoptosis of tumor cells. However, the mechanism of solanine-suppressing prostate cancer cell growth remains to be elucidated. This study investigates the inhibition mechanism of solanine on cancer development in vivo and in cultured human prostate cancer cell DU145 in vitro. Results show that solanine injection significantly suppresses the tumor cell growth in xenograft athymic nude mice. Solanine regulates the protein levels of cell cycle proteins, including Cyclin D1, Cyclin E1, CDK2, CDK4, CDK6, and P21 in vivo and in vitro. Also, in cultured DU145 cell, solanine significantly inhibits cell growth. Moreover, the administration of NAC, an active oxygen scavenger, markedly reduces solanine-induced cell death. Blockade of P38 MAPK kinase cannot suppress reactive oxygen species (ROS), but can suppress solanine-induced cell apoptosis. Also, inhibition of ROS by NAC inactivates P38 pathway. Taken together, the data suggest that inhibition of prostate cancer growth by solanine may be through blocking the expression of cell cycle proteins and inducing apoptosis via ROS and activation of P38 pathway. These findings indicate an attractive therapeutic potential of solanine for suppression of prostate cancer.

Alpha7 nicotinic acetylcholine receptor activation attenuated intestine-derived acute lung injury

BACKGROUND

Intestinal ischemia-reperfusion (IIR) could lead to acute lung injury, associated with severe alveolar epithelial cells inflammatory and oxidative injury. Alpha7 nicotinic acetylcholine receptor (α7nAChR) is an essential component of the cholinergic anti-inflammatory pathway. The aim of this study was to investigate the important role of α7nAChR on the lung subjected to IIR.

METHODS

Thirty-two Sprague-Dawley rats were randomly divided into four groups (n = 8 in each): sham group (group S), model group (group M), α7nAChR agonist PNU-282987-treated group (group PNU), and specific α7nAChR antagonist methyllycaconitine-treated group (group MLA). Intestinal IR damage was induced by clamping the superior mesenteric artery for 75 min, followed by a 120-min reperfusion. All rats were killed at 2 h after release of the clamps. The histologic examination of lungs was made, and lung water content was detected. Expression levels of malondialdehyde, tumor necrosis factor alpha, interleukin-6, and superoxide dismutase activity of the lungs were detected. Additionally, expression level of toll-like receptor (TLR)4 and nuclear factor-kappaB (NF-κB p65) in the nucleus of lung tissue and apoptosis-related protein (Bax, Bcl-2, and cleaved-caspase3) were detected using Western blot.

RESULTS

Lungs were damaged after intestine IR, manifested by higher lung water content, histologic score, concentrations of interleukin-6, tumor necrosis factor alpha, and malondialdehyde of group M than those of group S, accompanied with decreased superoxide dismutase activity (P < 0.05). PNU treatment could significantly improve the pulmonary function of rats subjected to IIR. These effects of activation of α7nAChR were associated with suppression of TLR4/NF-κB pathway and subsequent reduction of apoptosis-related protein. However, MLA treatment aggravated lung injury.

CONCLUSIONS

α7nAChR plays a role in acute lung injury induced by IIR via attenuating lung oxidative stress and inflammation through suppression of TLR4/NF-κB pathway, resulting in reduction of apoptosis in the lung.

Ulinastatin prevents acute lung injury led by liver transplantation

BACKGROUND

Little is known regarding the effect of ulinastatin (UTI) on acute lung injury (ALI) induced by orthotopic liver transplantation. This study aims to investigate the protective effect of UTI on ALI induced by orthotopic autologous liver transplantation (OALT) in a rat model and to explore the potential underlying mechanism.

MATERIALS AND METHODS

Rats were randomly allocated into the following four groups (n = 8 each): (i) sham control group (group sham); (ii) model group (underwent OALT) (group model); (iii) low-dose UTI-treated group (group u1), with UTI (50 U/g) administered intravenously both before the portal vein was occluded and after liver reperfusion started; and (iv) high-dose UTI-treated group (group uh), with UTI (100 U/g) given in the same way as group ul. The lung pathologic parameters, lung water content, and levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, malondialdehyde (MDA), superoxide dismutase (SOD) activity, RanBP-type and C3HC4-type zinc finger-containing protein 1 (RBCK1), and peroxiredoxin-2 (Prx-2) were assessed 8 h after OALT was performed.

RESULTS

According to histology, there was severe damage in the lung of group model accompanied by increases in the TNF-α, IL-1β, IL-6, and MDA levels and decreases in SOD activity and the expression of RBCK1 and Prx-2. UTI treatment significantly reduced the pathologic scores, lung water content, and TNF-α, IL-1β, IL-6, and MDA levels while restoring the SOD activity and expression of RBCK1 and Prx-2. Furthermore, compared with group u1, treatment with a high dose of UTI resulted in a better protective effect on the lung when assessed by the TNF-α, IL-1β, IL-6, and MDA levels and SOD activity.

CONCLUSIONS

UTI dose-dependently attenuates ALI that is induced by OALT in this rat model, which is mainly due to the suppression of the inflammatory response and oxidant stress, which may, in turn, be mediated by the upregulation of RBCK1 and Prx-2 expression.