Efficacy of methotrexate, doxorubicin, and cisplatin for osteosarcoma: Study protocol for a systematic review of randomized controlled trial.

BACKGROUND: This systematic review will address the efficacy and safety of methotrexate, doxorubicin, and cisplatin (MAP) for the treatment of patients with osteosarcoma. METHODS: We will retrieve the studies from the following 9 electronic databases: Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, the Allied and Complementary Medicine Database, and Chinese Biomedical Literature Database, China National Knowledge Infrastructure, VIP Information, and Wanfang Data. Two independent researchers will screen and select the relevant papers for eligibility after the search strategies have been conducted. All articles up to the present in any language, region will be considered in this study. A systematic review and data synthesis will be performed of randomized controlled trials of MAP for the treatment of patients with osteosarcoma. The primary outcome includes event-free survival. The secondary outcomes consist of overall survival, quality of life, and toxicity. In addition, 2 independent researchers will extract data, and will assess the quality of included studies by using Cochrane risk of bias tool. Results data will be pooled and meta-analysis will be conducted if >2 eligible studies will be included. RESULTS: This systematic review will evaluate the efficacy and safety of MAP for the treatment of patients with osteosarcoma. CONCLUSION: The findings of this study will summarize the up-to-date evidence of MAP for osteosarcoma, and may provide the guidance for the clinical practice, as well as the health policy maker. PROSPERO REGISTRATION NUMBER: PROSPERO CRD42018120004.

[The expression of calcium sensing receptor(CaSR) and MAPK pathway changes in myocardial cells of epilepsy rats].

OBJECTIVE: To investigate the changes of the myocardial cells in chronic epileptic rat model and to observe the expression of calcium sensing receptor(CaSR) and mitogen-activated proteinkinase(MAPK)pathway changes in epilepsy rats. METHODS: The chronic epileptic rat model was induced bypentetrazole (PTZ). Adult male Wistar rats were divided into 5 groups randomly, and there were 12 rats in each group. The rats in model group were treated with a sub-convulsivedose of PTZ (35 mg/kg) by intraperitoneal injection for 28 d. After stopping a week, the same dose of PTZ test was conducted. The control group was treated with isovolumetric saline instead of PTZ by intraperitoneal injection. According to Racine behavior grading standards the rat emerged two levels above epileptic seizure 5 consecutive times, which was considered the chronic epilepsy model successful ignition. The intervention factors included spermine(calcium-sensing receptor agonist, 3 µmol/L) and Chalhex231(calcium-sensing receptor inhibitor, 2 µmol/L). The serum creatine kinase (CK) and creatine kinase isoenzyme(CK-MB)were detected. The cardiac functions, morphological changes of rat myocardial tissue, myocardial cell ultrastructure, myocardial cell calcium sensing receptor and extracellular regulated protein kinase (ERK), p-ERK, p-JNK expression were carried out. RESULTS: Compared with normal control group, CK, CK-MB inPTZ group were increased obviously. The cardiac compliance and left ventricular function were decreased, E/A<1 by echocardiography. The myocardial ultrastructure showed serious injury. The expressions of CaSR and p-JNK were increased, but the expression of p-ERKwas decreased. Spermine could promote the expressions of CaSR and p-JNK, and decrease the expression of p-ERK in epilepsy; however, the role of Chalhex231 wasopposite. CONCLUSIONS: The level of CaSR expression increased in chronic epileptic rat model. CaSR activated the expressions of MAPK of the myocardial cells,andthen influenced the cardiac myocyte apoptosis.

Increased expression of calcium-sensing receptors in atherosclerosis confers hypersensitivity to acute myocardial infarction in rats.

Acute myocardial infarction (AMI) is a leading cause of death worldwide. Most cases of AMI result from coronary atherosclerosis (AS). The pathogenic mechanisms underlying AS lesions and AMI are incompletely understood. Calcium-sensing receptors (CaSR) belong to a family of G-protein-coupled receptors. We previously discovered that CaSR was expressed in the heart tissue of adult rats. CaSR may contribute to AMI in AS. We initially established a rat model of AS by injection of vitamin D(3) and feeding with a high-fat diet. Isoproterenol (ISO) was used to induce AMI. The MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH), cardiac troponin T (cTnT), tetrazolium chloride staining, and cardiac function parameters were selected as indicators of myocardial damage or necrosis. Cardiac apoptosis was analyzed by transferase dUTP nick-end labeling (TUNEL) assay. Expression of CaSR, Bcl-2, Bax, caspase-3, p-ERK1/2, p-JNK, and p-p38 were determined by Western blot analysis. Compared with the control group, levels of cTnT, CK-MB, and LDH; number of TUNEL-positive cells; and expression of CaSR, Bax, caspase-3, p-ERK1/2, p-JNK and p-p38, were significantly increased, whereas cardiac function and expression of Bcl-2 were decreased markedly in isoproterenol (ISO)-treated group (C/ISO) and AS groups. These changes were significant in the AS/ISO group than in the C/ISO group or AS group. The upregulation of CaSR during AS formation renders hypersensitivity to AMI. Activation of the pro-apoptotic mitochondria pathway and JNK-p38 MAPK pathway triggered by increased expression of CaSR may be one of molecular mechanisms underlying AMI in AS.

Increased expression of calcium-sensing receptors induced by ox-LDL amplifies apoptosis of cardiomyocytes during simulated ischaemia-reperfusion.

1. Acute myocardial infarction (AMI) is strongly associated with atherosclerosis, and is responsible for significant morbidity and mortality worldwide. The pathogenic mechanisms that underlie atherosclerosis and AMI are undefined at present. The calcium-sensing receptor (CaSR) is a member of the superfamily of G-protein coupled receptors. It has been demonstrated previously that the expression of CaSR is increased in atherosclerotic cardiac tissue of rats. It has also been suggested that CaSR has a crucial role in cardiac ischaemia-reperfusion injury, apoptosis and hypertrophy. However, it remains to be determined whether an increase in the expression of CaSR influences the sensitivity of cardiomyocytes to AMI. 2. The present study used cultured ventricular cardiomyocytes from neonatal rats to investigate the effect of oxidized low-density lipoprotein (ox-LDL), ischaemia-reperfusion, GdCl(3) (an agonist of CaSR) and NPS-2390 (an antagonist of CaSR) on the expression of CaSR. The amount of apoptosis, alterations in the morphology of the cells, the intracellular calcium concentration ([Ca(2+)](i)) and components of critical mitochondrial pathways were also analysed. 3. Cardiomyocytes treated with ox-LDL showed upregulated expression of CaSR, cytochrome c (cyt-c), Bax and activated caspase 3 (17 kD) and downregulated expression of Bcl-2, as well as elevated [Ca(2+)](i) and apoptosis. Application of GdCl(3) augmented these effects, and NPS-2390 decreased the expression of CaSR and reduced apoptosis. 4. In conclusion, ox-LDL was found to increase the expression of CaSR in a manner that was dependent on time and dose. It also augmented apoptosis during simulated ischaemia-reperfusion in cultured ventricular cardiomyocytes from neonatal rats.

[Increased myocardial expression of calcium-sensing receptor and apoptosis in a rat model of atherosclerosis].

OBJECTIVE: To observe the effect of hyperlipidemia and atherosclerosis on rat myocardial expression of calcium-sensing receptor and apoptosis. METHODS: The rat atherosclerosis model was induced by intraperitoneal injection of VD(3) (6 x 10(5) U/kg) and high cholesterol diet. Wistar rats were divided into two groups: (1) Control group; (2) AS group (n = 12 each). The expressions of CaSR, Bcl-2, Bax and caspase-3 were analyzed by Western blot and RT-PCR. Apoptotic cells were observed by TUNEL assay. The morphological changes of abdominal aorta and cardiac tissues were observed under optical and electro microscopes. The activity of LDH, CK, SOD and the content of MDA were assayed with ultraviolet spectrophotometer. The level of cTnT was detected by electrochemical immunofluorescence. RESULTS: Compared with control group, the activity of LDH and CK, the content of MDA and cTnT, the apoptosis index, the expression of CaSR, Bax and caspase-3 were significantly increased, but the SOD activity and Bcl-2 expression were significantly decreased, the myocardial ultrastructure injury was significantly aggravated in the AS group (all P < 0.05). CONCLUSION: Hyperlipidemia and atherosclerosis can up-regulate myocardial calcium-sensing receptor expression, promote myocardial apoptosis, aggravate oxidative stress and myocardial ischemia.