Radiobiological characteristics of cancer stem cells from esophageal cancer cell lines

AIM: To study the cancer stem cell population in esophageal cancer cell lines KYSE-150 and TE-1 and identify whether the resulting stem-like spheroid cells display cancer stem cells and radiation resistance characteristics.

Empirical Study on Chemotherapeutic Susceptibility of SP Cells in Human Pulmonary Adenocarcinoma Cell Line A549 in Vitro

OBJECTIVE To explore the chemotherapeutic susceptibility of SP cells in human pulmonary adenocarcinoma cell line A549 and the possible mechanism of multidrug resistance.METHODS SP and non-SP （NSP） cells in the cell line A549 were isolated by fluorescence activated cell sorter. The susceptibility of SP and NSP cells to DDP, 5-FU, VP16, NVB and GEM was detected by a drug susceptibility test, and IC50s were calculated 24 h a er the chemotherapy; and then a er a 2-hour IC50 treatment with 5 chemotherapeutic drugs on the 2 subsets of NSP cells, the intracellular drug levels were determined and analyzed using high performance liquid chromatograph.RESULTS There was no statistical signifi cance in comparison of the di. erences in IC50s and in intracellular drug levels a er DDP treatment between the 2 subsets （P 〉 0.05）, （P 〉 0.05）. However,all IC50s of the other 4 drugs were significantly higher in the SP cells than in the NSP cells （P 〈 0.01）. A er the chemotherapy, the intracellular drug levels of the other 4 drugs were significantly lower in SP cells than in NSP cells （P 〈 0.01）.CONCLUSION Compared to NSP cells, SP cells in the cell line A549 have stronger resistance to the chemotherapeutics. The multidrug resistance of SP cells closely correlates with the function of SP cells discharging chemotherapeutic agents.

Glioblastoma stem cells resistant to temozolomide-induced autophagy

Background Recent studies have demonstrated the existence of a small fraction of cells with features of primitive neural progenitor cells and tumor-initiating function in brain tumors. These cells might represent primary therapeutic target for complete eradication of the tumors. This study aimed to determine the resistant phenotype of glioblastoma stem cells （GSCs） to temozolomide （TMZ） and to explore the possible molecular mechanisms underlying TMZ resistance. Methods Freshly resected glioblastoma specimen was collected and magnetic isolation of GSCs was carried out using the Miltenyi Biotec CD133 Cell Isolation kit. The cytotoxic effect of TMZ on CD133^＋ and CD133^- glioblastoma cells was determined by using the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Autophagy-related proteins （Beclin-1, LC3 and Atg5） and cleaved caspase-3 （p17） were analyzed by Western blotting. Immunofluorescent staining was used to detect Atg5, glial fibrillary acidic protein （GFAP） and CD133 expression in glioblastoma cells. Statistical analysis was carried out using SPSS 10.0 software. For all tests, the level of statistical significance was set at P 〈0.05. Results CD133^＋ glioblastoma ceils exhibited neurosphere-like growth in vitro and high expression of CD133 stem cell marker. The growth-inhibiting rate in CD133- glioblastoma cells treated with 5 or 50 pmol/L TMZ was significantly higher than that in CD133^＋ glioblastoma cells （（14.36±3.75）% vs （2.54±1.36）% or （25.95±5.25）% vs （2.72±1.84）%, respectively, P 〈0.05）. Atg5, LC3-11 and Beclin-1 levels were significantly lower in CD133^＋ glioblastoma cells than those in autologous CD133^- cells after TMZ treatment （P 〈0.05）. Caspase-3 was mildly activated only in CD133^- glioblastoma cells after exposure to TMZ （P 〈0.05）. Immunofluorescent staining revealed elevated expression of Atg5 in GFAP^＋ cells following TMZ treatment. Conclusions The GSCs display strong capability of tumor＇s resistance to TMZ. This resistance is probably contributed by the CD133^＋ cells with down-regulation of autophagy-related proteins. Future treatment should target this small population of cancer stem cells in tumors to improve survival of patients.

Breast cancer stem-like cells can promote metastasis by activating platelets and down-regulating antitumor activity of natural killer cells

OBJECTIVE:To investigate whether cancer stem cells(CSCs) more efficiently activating platelets and evading immune surveillance than non-CSCs thus promoting metastasis.METHODS:We enriched and identified sphereforming cells(SFCs) and coincubated washed platelets with several platelet activators including collagen,4T1 and SFCs.Platelet-coating tumor cells,platelet activation and TGF-β1 release were analyzed.Then natural kell cells(NK) were incubated with supernatants of different activated platelet samples what we called sample release(SR).The degranulation assay and NKG2 D expression on NK cells were conducted by flow cytometry.Finally tissue factor(TF) expression of SFCs or 4T1 were evaluated by western blot.RESULTS:Breast cancer cell line 4T1 could form spheres in serum-free medium at low adherence.Sphere-forming cells expressed high levels of the CD24-/lowCD44 + stem cell phenotype.Both sphere-forming cells or 4T1 were coated with abundant platelets while sphere-forming cells induced significantly higher expression of platelet activating receptor CD62 p than 4T1 did(P < 0.01).And sphere-forming cells induced platelets to produce more TGF-β1 than 4T1 did(P < 0.01).Furthermore,sample releases induced by sphere-forming cells caused more vigorous inhibition of NK cells antitumor reactivity(P < 0.05) and reduced NKG2 D expression(P < 0.01).The final results showed that sphere-forming cells expressed higher levels of TF than 4T1(P < 0.05).CONCLUSION:Our findings indicate that CSCs could efficiently activate platelets,induce platelets to secrete more TGF-β1,decrease NKG2 D expression and inhibit antitumor activity of NK cell,compared with 4T1.And higher levels of TF expression of CSCs may account for this correlation of CSCs and platelets.

Recent advances of miRNAs in the development and clinical application of gastric cancer

Gastric cancer(GC)is one of the most common malignant tumors.The mechanism of how GC develops is vague,and therapies are inefficient.The function of microRNAs(miRNAs)in tumorigenesis has attracted the attention from many scientists.During the development of GC,miRNAs function in the regulation of different phenotypes,such as proliferation,apoptosis,invasion and metastasis,drug sensitivity and resistance,and stem-cell-like properties.MiRNAs were evaluated for use in diagnostic and prognostic predictions and exhibited considerable accuracy.Although many problems exist for the application of therapy,current studies showed the antitumor effects of miRNAs.This paper reviews recent advances in miRNA mechanisms in the development of GC and the potential use of miRNAs in the diagnosis and treatment of GC.