OBJECTIVETo study the reversal effect of nomegestrol acetate (NOM) on mutidrug resistance (MDR) in MCF7/ADR and its mechanism.

METHODSUsing tetrazolium dye assay, effects of various concentrations of NOM on sensitivity to ADR in MCF7/ADR was studied. Expression of MDR related genes MDR1, glutathoine S-transferase Pi (GSTpi), Topoisomerase II alpha (Topo II alpha) and MDR related protein (MRP) were assayed by reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry assay. Using flow cytometry (FCM), intracellular ADR concentration effects on cell cycle were observed.

RESULTSNOM significantly reversed MDR in MCF7/ADR. After NOM 20, 10 and 5 micromol/L treatment, the chemosensitivity to ADR increased to 21, 12 and 8 times. The reversal activity of NOM was stronger than that of the precursor compound megestrol acetate, and was comparable to that of verapamail. After treatment with NOM 5 micromol/L both MDR1 and GSTpi mRNA genes expression began to decline on D2 (P < 0.05, & P < 0.01) and reached the lowest level on D3 (both P < 0.01), but the expression levels began to rise on D6 again (both P < 0.05). The expression of MRP and Topo II alpha gave no significant change. Changes of P-gp and GSTpi protein expressions were similar to those of their mRNA expressions, showing early decline and late rise. Two hours after NOM 20, 10, and 5 micromol/L treatment, intracellular ADR concentration increased 2.7, 2.3 and 1.5 times, respectively. FCM data showed that after forty-eight hours, combined administration of NOM (20 micromol/L) and ADR (from low concentration to high concentration), MCF7/ADR cells showed gradual arrest in the G(2)M phase with the increase of ADR dose.

CONCLUSIONNOM has strong reversal effects on MDR in MCF7/ADR. The reversal takes place via different routes, i.e. down regulating mRNA and protein expression levels of MDR1 and GSTpi, increasing intracellular drug concentration, and enhancing the arrest of ADR in cells at G(2)M phase.

ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Antigens, Neoplasm ; Breast Neoplasms ; genetics ; pathology ; Cell Survival ; drug effects ; DNA Topoisomerases, Type II ; genetics ; metabolism ; DNA-Binding Proteins ; Drug Resistance, Neoplasm ; genetics ; Gene Expression Regulation, Neoplastic ; drug effects ; Glutathione S-Transferase pi ; Glutathione Transferase ; genetics ; metabolism ; Humans ; Immunohistochemistry ; Inhibitory Concentration 50 ; Isoenzymes ; genetics ; metabolism ; Megestrol ; Multidrug Resistance-Associated Proteins ; genetics ; metabolism ; Norpregnadienes ; pharmacology ; Progesterone Congeners ; pharmacology ; RNA, Messenger ; drug effects ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Cells, Cultured ; Verapamil ; pharmacology

Objective To analyze the clinical characteristics of patients with liver cirrhosis complicated with portal vein thrombosis (PVT) and to explore the high risk factors of PVT formation for the prevention and early treatment of PVT.Methods From January 2012 to August 2017,at the Second Hospital Affiliated to Chongqing Medical University,160 hospitalized liver cirrhosis patients complicated with PVT were selected as PVT group and secondary PVT caused by other factors were excluded.At the same time,250 patients with liver cirrhosis without PVT were enrolled as the control group.According to the history of splenectomy,the patients were divided into splenectomy group and non-splenectomy group.The risk factors correlated with the formation of PVT such as hemoglobin,platelet count,prothrombin time (PT),international normalized ratio (INR) and prothrombin activity were collected.T test,chisquare test and non-parameter rank test were performed for the comparison of above indexes between PVT group and control group.Single factor analysis and multifactor logistic regression were used to analyze the risk factors of PVT formation.Results The average age of patients in PVT group ((54.5 ±11.4) years) was significantly older than that in control group ((51.8±911.9) years,t=2.29,P=0.02).The results of multifactor logistic regression analysis showed that hemoglobin,platelet count,PT and INR were risk factors of PVT formation (all P＜0.05).The proportion of patients with Child-Pugh class C cirrhosis in PVTgroup was higher than that in control group (16.2％,26/160 vs.4.4％,11/250),and the difference was statistically significant (x2 =16.60,P＜0.01).In PVT group,27.5％ (44/160) patients had a history of splenectomy,and 8.4％ (21/250) patients of the control group had a history of splenectomy,and the difference between two groups was statistically significant (x2=26.70,P＜0.01).The platelet counts of patients with splenectomy were higher than those of patients without splenectomy ((176.2±98.7)× 109/L vs.(78.3±57.8) × 109/L),and the difference was statistically significant (t=11.08,P＜0.01).The incidence of complications in PVT group was much higher than that in control group (45.0％,72/160 vs.10.0％,25/250,x2=66.17,P＜0.05).There were no statistically significant differences in the incidence of gastrointestinal bleeding and mortality between PVT treatment group and non-treatment group (25.6％,11/43 vs.23.8％,10/42;18.6％,8/43 vs.31.0％,13/42,respectively;both P＞0.05).Conclusions Decreased hemoglobin,increased platelet count,prolonged PT,increased INR and Child-Pugh classification are the risk factors for PVT formation.Increased platelet after splenectomy is an independent risk factor for PVT formation.