搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

Immunotherapy with the EGFR-specific mAb cetuximab is clinically effective in 10-20% of patients with squamous cell carcinoma of the head and neck (SCCHN). Little information is available about the mechanism(s) underlying patients' differential clinical response to cetuximab-based immunotherapy,although this information may contribute to optimizing the design of cetuximab-based immunotherapy. Our understanding of these mechanisms would benefit from the characterization of the variables which influence the extent of cell dependent-lysis of SCCHN cells incubated with cetuximab in vitro. Therefore,in this study we have investigated the role of FcgammaR IIIa-158 genotype expressed by effector NK cells,cetuximab concentration,and EGFR expression level by SCCHN cells in the extent of their in vitro lysis and in the degree of NK cell activation. PBMC or purified CD56+ NK cells genotyped at IIIa codon 158 and SCCHN cell lines expressing different levels of EGFR have been used as effectors and targets,respectively,in antibody dependent cellular cytotoxicity (ADCC) assays. Furthermore,supernatants from ADCC assays were analyzed for cytokine and chemokine levels using multiplexed ELISA. We found that the extent of lysis of SCCHN cells was influenced by the EGFR expression level,cetuximab concentration,and FcgammaR polymorphism. Effector cells expressing the FcgammaR IIIa-158 VV allele were significantly (P textless 0.0001) more effective than those expressing FcgammaR IIIa VF and FF [corrected] alleles in mediating lysis of SCCHN cells expressed higher levels of the activation markers CD69 and CD107a,and secreted significantly (P textless 0.05) larger amounts of inflammatory cytokines and chemokines. IL-2 or IL-15 treatment increased cetuximab-mediated ADCC by poor binding FcgammaR IIIa 158 FF expressing NK cells. The importance of the FcgammaR IIIa-158 polymorphism in cytotoxicity of SCCHN cells by NK cells supports a potential role for immune activation and may explain patient variability of cetuximab mediated clinical responses. Cellular and secreted immune profiles and FcgammaR genotypes from patients' lymphocytes may provide clinically useful biomarkers of immune activation in cetuximab treated patients. View Publication

Throughout its history,chronic myeloid leukemia (CML) has set precedents for cancer research and therapy. These range from the identification of the first specific chromosomal abnormality associated with cancer to the development of imatinib as a specific,targeted therapy for the disease. The successful development of imatinib as a therapeutic agent for CML can be attributed directly to decades of scientific discoveries. These discoveries determined that the BCR-ABL tyrosine kinase is the critical pathogenetic event in CML and an ideal target for therapy. This was confirmed in clinical trials of imatinib,with imatinib significantly improving the long-term survival of patients with CML. Continuing in this tradition of scientific discoveries leading to improved therapies,the understanding of resistance to imatinib has rapidly led to strategies to circumvent resistance. Continued studies of hematologic malignancies will allow this paradigm of targeting molecular pathogenetic events to be applied to many additional hematologic cancers. View Publication

PURPOSE: Genz-644282 [8,9-dimethoxy-5-(2-N-methylaminoethyl)-2,3-methylenedioxy-5H-dibenzo[c,h][1,6]naphthyridin-6-one] has emerged as a promising candidate for antitumor agents. This report describes the bone marrow colony-forming unit,granulocyte macrophage (CFU-GM) and tumor cell CFU activity of topoisomerase I (Top1) inhibitors,such as Genz-644282,topotecan,irinotecan/SN-38,and ARC-111,and examines their activity in several human tumor xenograft models. EXPERIMENTAL DESIGN: Colony-forming assays were conducted with mouse and human bone marrow and eight human tumor cell lines. In addition,29 human tumor cell lines representing a range of histology and potential resistance mechanisms were assayed for sensitivity to Genz-644282 in a 72-hour exposure assay. The efficacy of Genz-644282 was compared with standard anticancer drugs (i.e.,irinotecan,docetaxel,and dacarbazine) in human tumor xenografts of colon cancer,renal cell carcinoma,non-small cell lung cancer,and melanoma. RESULTS: Human bone marrow CFU-GM was more sensitive to the Top1 inhibitors than was mouse bone marrow CFU-GM. The ratio of mouse to human IC(90) values was more than 10 for the camptothecins and less than 10 for Genz-644282,which had more potency as a cytotoxic agent toward human tumor cells in culture than the camptothecins in the colony-forming and 72-hour proliferation assays. Genz-644282 has superior or equal antitumor activity in the human tumor xenografts than the standard drug comparators. CONCLUSIONS: On the basis of preclinical activity and safety,Genz-644282 was selected for development and is currently undergoing phase 1 clinical trial. View Publication

RNA-binding motif protein 15 (RBM15) is involved in the RBM15-megakaryoblastic leukemia 1 fusion in acute megakaryoblastic leukemia. Although Rbm15 has been reported to be required for B-cell differentiation and to inhibit myeloid and megakaryocytic expansion,it is not clear what the normal functions of Rbm15 are in the regulation of hematopoietic stem cell (HSC) and megakaryocyte development. In this study,we report that Rbm15 may function in part through regulation of expression of the proto-oncogene c-Myc. Similar to c-Myc knockout (c-Myc-KO) mice,long-term (LT) HSCs are significantly increased in Rbm15-KO mice due to an apparent LT-HSC to short-term HSC differentiation defect associated with abnormal HSC-niche interactions caused by increased N-cadherin and beta(1) integrin expression on mutant HSCs. Both serial transplantation and competitive reconstitution capabilities of Rbm15-KO LT-HSCs are greatly compromised. Rbm15-KO and c-Myc-KO mice also share related abnormalities in megakaryocyte development,with mutant progenitors producing increased,abnormally small low-ploidy megakaryocytes. Consistent with a possible functional interplay between Rbm15 and c-Myc,the megakaryocyte increase in Rbm15-KO mice could be partially reversed by ectopic c-Myc. Thus,Rbm15 appears to be required for normal HSC-niche interactions,for the ability of HSCs to contribute normally to adult hematopoiesis,and for normal megakaryocyte development; these effects of Rbm15 on hematopoiesis may be mediated at least in part by c-Myc. View Publication

BACKGROUND: Mammalian target of rapamycin (mTOR) is a serine/threonine kinase involved in multiple intracellular signaling pathways promoting tumor growth. mTOR is aberrantly activated in a significant portion of breast cancers and is a promising target for treatment. Rapamycin and its analogues are in clinical trials for breast cancer treatment. Patterns of gene expression (metagenes) may also be used to simulate a biologic process or effects of a drug treatment. In this study,we tested the hypothesis that the gene-expression signature regulated by rapamycin could predict disease outcome for patients with breast cancer. RESULTS: Colony formation and sulforhodamine B (IC50 textless 1 nM) assays,and xenograft animals showed that MDA-MB-468 cells were sensitive to treatment with rapamycin. The comparison of in vitro and in vivo gene expression data identified a signature,termed rapamycin metagene index (RMI),of 31 genes upregulated by rapamycin treatment in vitro as well as in vivo (false discovery rate of 10%). In the Miller dataset,RMI did not correlate with tumor size or lymph node status. High (textgreater75th percentile) RMI was significantly associated with longer survival (P = 0.015). On multivariate analysis,RMI (P = 0.029),tumor size (P = 0.015) and lymph node status (P = 0.001) were prognostic. In van 't Veer study,RMI was not associated with the time to develop distant metastasis (P = 0.41). In the Wang dataset,RMI predicted time to disease relapse (P = 0.009). CONCLUSION: Rapamycin-regulated gene expression signature predicts clinical outcome in breast cancer. This supports the central role of mTOR signaling in breast cancer biology and provides further impetus to pursue mTOR-targeted therapies for breast cancer treatment. View Publication

Aldehyde dehydrogenase (ALDH) activity has been implicated in multiple biological and biochemical pathways and has been used to identify potential cancer stem cells. Our main hypothesis is that ALDH activity may be a lung cancer stem cell marker. Using flow cytometry,we sorted cells with bright (ALDH(br)) and dim (ALDH(lo)) ALDH activity found in H522 lung cancer cell line. We used in vitro proliferation and colony assays as well as a xenograft animal model to test our hypothesis. Cytogenetic analysis demonstrated that the ALDH(br) cells are indeed a different clone,but when left in normal culture conditions will give rise to ALDH(lo) cells. Furthermore,the ALDH(br) cells grow slower,have low clonal efficiency,and give rise to morphologically distinct colonies. The ability to form primary xenografts in NOD/SCID mice by ALDH(br) and ALDH(lo) cells was tested by injecting single cell suspension under the skin in each flank of same animal. Tumor size was calculated weekly. ALDH1A1 and ALDH3A1 immunohistochemistry (IHC) was performed on excised tumors. These tumors were also used to re-establish cell suspension,measure ALDH activity,and re-injection for secondary and tertiary transplants. The results indicate that both cell types can form tumors but the ones from ALDH(br) cells grew much slower in primary recipient mice. Histologically,there was no significant difference in the expression of ALDH in primary tumors originating from ALDH(br) or ALDH(lo) cells. Secondary and tertiary xenografts originating from ALDH(br) grew faster and bigger than those formed by ALDH(lo) cells. In conclusion,ALDH(br) cells may have some of the traditional features of stem cells in terms of being mostly dormant and slow to divide,but require support of other cells (ALDH(lo)) to sustain tumor growth. These observations and the known role of ALDH in drug resistance may have significant therapeutic implications in the treatment of lung cancer. View Publication