Biomaterial-based platforms for cancer stem cell enrichment and study

Cancer stem cells(CSCs)are a relatively rare subpopulation of tumor cell with self-renewal and tumorigenesis capabilities.CSCs are associated with cancer recurrence,progression,and chemoradiotherapy resistance.Establishing a reliable platform for CSC enrichment and study is a prerequisite for understanding the characteristics of CSCs and discovering CSC-related therapeutic strategies.Certain strategies for CSC enrichment have been used in laboratory,particularly fluorescence-activated cell sorting(FACS)and mammosphere culture.However,these methods fail to recapitulate the in vivo chemical and physical conditions in tumors,thus potentially decreasing the malignancy of CSCs in culture and yielding unreliable research results.Accumulating research suggests the promise of a biomaterial-based three-dimensional(3 D)strategy for CSC enrichment and study.This strategy has an advantage over conventional methods in simulating the tumor microenvironment,thus providing a more effective and predictive model for CSC laboratory research.In this review,we first briefly discuss the conventional methods for CSC enrichment and study.We then summarize the latest advances and challenges in biomaterial-based 3 D CSC platforms.Design strategies for materials,morphology,and chemical and physical cues are highlighted to provide direction for the future construction of platforms for CSC enrichment and study.

Effects of Losartan on Cell Apoptosis and Expression of Caspase-3 and JNK Proteins in Kidney Tissue in Renal Interstitial Fibrosis Rats

[Objectives]To investigate the effects of losartan on cell apoptosis and the expression of caspase-3 and JNK proteins in kidney tissue in the adenine-induced renal fibrosis rats.[Methods]Thirty Wistar rats were randomly divided into three groups:control group(n=10),model group(n=10)and losartan group(n=10).The rats in the control group received saline,while those in the model group and losartan group both received adenine by gavage,for 21 d.After the renal interstitial fibrosis model was established,the rats in the losartan group were treated with losartan[10 mg/(kg·d)],while the rats in the control group and the model group rats were administered with the same amount of saline.The course of treatment was 30 d.Finally,the renal function,blood urea nitrogen(BUN),serum creatinine(Scr),creatinine clearance rate(Ccr)and the pathological morphology of the rats were detected.The apoptosis of renal tubular epithelial cells was tested by TUNEL.The caspase-3 and JNK protein expression was tested by Western blotting.[Results]After administering adenine for 21 d,the BUN,24 MTP and kidney/body weight in the model group were increased,significantly higher than the control group(P<0.01),and the Ccr was remarkably decreased(P<0.01),signifying that the renal interstitial fibrosis model was successfully built.After treating with losartan for 30 d,the Scr,BUN,and 24 MTP were significantly decreased(P<0.01),and the Ccr was significantly increased in the losartan group(P<0.01).In addition,in comparison to the model group,renal tubular epithelial apoptosis was decreased and caspase-3 and JNK expression was downregulated in the losartan group(P<0.05).[Conclusions]Losartan can reduce the adenine-induced elevation of Scr,BUN and 24 hMPT,increase Ccr,improve general condition of renal interstitial fibrosis in rats and ameliorate the progression of chronic kidney failure(CKD).The effectiveness of losartan is probably due to its ability to regulate caspase-3,JNK protein expression and attenuate renal cell apoptosis.

Iridoid glycosides extracted from Zhizi(Fructus Gardeniae)decrease collagen-induced platelet aggregation and reduce carotid artery thrombosis in an invivo rat model

OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activity of iridoid glycosides (IGs) in a rat model of carotid artery thrombosis. The effects on coagulation, such as thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT), and the effect on collagen-induced platelet aggregation in vivo were investigated. Rats were intragastrically administered IGs (50, 100 or 200 mg/ kg) twice daily for 3 days. RESULTS: IGs were shown for the first time to have an antithrombotic action through the inhibition of platelet aggregation, with little effect on the coagulation time of peripheral blood. Our results also showed that IGs may significantly and dose-dependently reduce arterial thrombus load in a model of carotid artery thrombosis and inhibit collagen-induced platelet aggregation in rats. IGs (100or 200 mg/kg) had no significant effect on APTT and PT, but did lengthenTT at a higher dose. CONCLUSION: These data, together with the previously reported neuroprotective effects of IGs in rats with cerebral ischemia, suggest that the antithrombotic action of IGs may potentially contribute to the treatment of cerebral ischemic diseases, including cerebral apoplexy.

Selectivity of biopolymer membranes using HepG2 cells

Bioartificial liver(BAL)system has emerged as an alternative treatment to bridge acute liver failure to either liver transplantation or liver regeneration.One of the main reasons that the efficacy of the current BAL systems was not convincing in clinical trials is attributed to the lack of friendly interface between the membrane and the hepatocytes in liver bioreactor,the core unit of BAL system.Here,we systematically compared the biological responses of hepatosarcoma HepG2 cells seeded on eight,commercially available biocompatible membranes made of acetyl cellulose–nitrocellulose mixed cellulose(CA–NC),acetyl cellulose(CA),nylon(JN),polypropylene(PP),nitrocellulose(NC),polyvinylidene fluoride(PVDF),polycarbonate(PC)and polytetrafluoroethylene(PTFE).Physicochemical analysis and mechanical tests indicated that CA,JN and PP membranes yield high adhesivity and reasonable compressive and/or tensile features with friendly surface topography for cell seeding.Cells prefer to adhere on CA,JN,PP or PTFE membranes with high proliferation rate in spheriod-like shape.Actin,albumin and cytokeratin 18 expressions are favorable for cells on CA or PP membrane,whereas protein filtration is consistent among all the eight membranes.These results further the understandings of cell growth,morphology and spreading,as well as protein filtration on distinct membranes in designing a liver bioreactor.