Expression of CD44,CD24 and ESA in pancreatic adenocarcinoma cell lines varies with local microenvironment

BACKGROUND:Emerging evidence suggests that pancreatic adenocarcinoma is hierarchically organized and sustained by pancreatic cancer stem cells.Furthermore,elimination of these cells is possible and therapeutically relevant.This study aimed to investigate the expression patterns of pancreatic cancer stem cell surface markers CD44,CD24 and ESA in pancreatic adenocarcinoma cell lines and explore the influence of their local microenvironment.METHODS:Flow cytometry was used to analyze the expression patterns of CD44,CD24 and ESA in five pancreatic adenocarcinoma cell lines (PANC-1,PC-2,MIA-Paca-2,AsPC-1 and BxPC-3).In addition,the capacity for sphereformation in serum-free medium of four cell lines (PANC-1,PC-2,MIA-Paca-2 and BxPC-3) was assessed.Then,the same assays were performed when tumor cell spheres were developed.The role of sonic hedgehog (SHH) in cell spheres from PANC-1 and MIA-Paca-2 were also assessed by RT-PCR.RESULTS:CD44 and CD24 were detected in PANC-1.Only CD44 expression was detected in PC-2,MIA-Paca-2 and AsPC-1.CD44,CD24 and ESA were all detected in BxPC-3.Tumor cell spheres developed in PANC-1 and MIA-Paca-2 in serumfree medium.This was accompanied by an increase in CD24 expression and a decrease in CD44 expression in PANC-1.Interestingly,the expression of CD44 and CD24 returned to initial levels once the medium was changed back from serumfree to serum-containing medium.No significant change in the expression of CD44 was detected in MIA-Paca-2.Furthermore,the relative quantification of SHH mRNA in PANC-1 cell spheres was significantly higher than that in cells cultured in the serum-containing medium.CONCLUSION:The expression patterns of the pancreatic cancer stem cell surface markers CD44,CD24 and ESA were diverse in different pancreatic adenocarcinoma cell lines and changed with their local microenvironment.

Effects of CpG-ODNs on phenotype and function of monocyte-derived dendritic cells in chronic hepatitis B

AIM:To study the effects of synthetic nonmethylated CpG-containing oligodeoxynucleotides(CpG-ODNs) ,either alone or combined with recombinant Hepatitis B surface antigen(HBsAg) polypeptide,on the phenotype,function,and intracellular signaling pathways of monocyte-derived dendritic cells(DCs) in patients with chronic hepatitis B(CHB) .METHODS:Peripheral blood monocytes isolated from CHB patients and healthy volunteers were induced to be dendritic cells by recombinant human granulocyte-monocyte colony stimulating factor and interleukin-4.The DCs were then treated with CpG-ODNs,CpGODNs/HBsAg,or tumor necrosis factor(TNF)-αfor 18 h.The expression of surface molecules including HLA-DR,CD86,and CD1a in DCs were detected by flow cytometry,and the expression of signal transducers and activators of transcription(STAT1,3,4,5,6) and suppressors of cell signaling(SOCS1,3) were determined by Western blotting assay.In addition,the capacity of DCs to stimulate allogeneic T lymphocytes and the amount of IL-12p70 released from DCs were measured.RESULTS:In the DCs derived from patients with CHB,treatment with TNF-α,CpG-ODNs,or CpG-ODNs/HBsAg,as compared to the vector control,significantly increased the expression of HLA-DR,stimulated the release of IL-12p70,and enhanced the capacity of DCs to stimulate allogenic T lymphocytes.The expressions of STAT1/4/6 and SOCS1/3,but not STAT3/5,were upregulated by TNF-α,CpG-ODNs,and CpG-ODNs/HBsAg.In addition,the expression of CD1a was upregulated only in the presence of both CpG-ODNs and HBsAg.CONCLUSION:The treatment with CpG-ODNs,either alone or combined with HBsAg,has a remarkable stimulatory effect on the impaired phenotype and function of DCs in CHB,possibly by regulating the expression of STAT1,4,6 and SOCS1,3.

Expression of CD28 and CTLA4 on T Cells in Bone Morrow of Immune-mediated Aplastic Anemia Mice

Summary： To investigate the expression and significance of CD28 and CTLA4 on T cells in bone marrow of aplastic anemia （AA） mice, in vitro bone marrow mononuclear cells （BMMNCs） were activated through being incubated with PHA （15 μg/mL）. The expression of CD28 and CTLA4 on T cells incubated with or without PHA was detected by two-color flow cytometry. The expression of CD28 and CTLA4 was significantly increased after PHA stimulation. In the AA mice. the expression of CD28 with or without PHA stimulation was both higher than that in the normal mice （both P〈0.01）, but the expression of CTLA4 with or without PHA stimulation showed no significant difference in comparison to that in the normal mice （both P〉0.05）. In the AA mice, there were more activation and activated potential of T cells than the normal, and the abnormal expression of CD28 and CTLA4 may participate in immunological disorder mediated by T cells.

Enzyme-linked immunosorbent assays for quantification of MMAE-conjugated ADCs and total antibodies in cynomolgus monkey sera

Antibody-drug conjugates(ADCs)are commonly heterogeneous and require extensive assessment of exposure-efficacy and exposure-safety relationships in preclinical and clinical studies.In this study,we report the generation of a monoclonal antibody against monomethyl auristatin E(MMAE)and the development,validation,and application of sensitive and high-throughput enzyme-linked immunosorbent assays(ELISA)to measure the concentrations of MMAE-conjugated ADCs and total antibodies(tAb,antibodies in ADC plus unconjugated antibodies)in cynomolgus monkey sera.These assays were successfully applied to in vitro plasma stability and pharmacokinetic(PK)studies of SMADC001,an MMAE-conjugated ADC against trophoblast cell surface antigen 2(TROP-2).The plasma stability of SMADC001 was better than that of similar ADCs coupled with PEG4-Val-Cit,Lys(m-dPEG24)-Cit,and Val-Cit linkers.The developed ELISA methods for the calibration standards of ADC and tAb revealed a correlation between serum concentrations and the OD450 values,with R2 at 1.000,and the dynamic range was 0.3-35.0 ng/mL and 0.2-22.0 ng/mL,respectively;the intra-and inter-assay accuracy bias%ranged from -12.2% to -5.2%,precision ranged from -12.4% to -1.4%,and the relative standard deviation(RSD)was less than 6.6% and 8.7%,respectively.The total error was less than 20.4%.The development and validation steps of these two assays met the acceptance criteria for all addressed validation parameters,which suggested that these can be applied to quantify MMAE-conjugated ADCs,as well as in PK studies.Furthermore,these assays can be easily adopted for development of other similar immunoassays.