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Abstract Background Glioblastoma Multiforme (GBM) is the most common and invasive astrocytic tumor associated with dismal prognosis. Treatment for GBM patients has advanced, but the median survival remains a meager 15 months. In a recent study, 20,000 genes from 21 GBM patients were sequenced that identified frequent mutations in ion channel genes. The goal of this study was to determine whether ion channel mutations have a role in disease progression and whether molecular targeting of ion channels is a promising therapeutic strategy for GBM patients. Therefore, we compared GBM patient survival on the basis of presence or absence of mutations in calcium, potassium and sodium ion transport genes. Cardiac glycosides, known sodium channel inhibitors, were then tested for their ability to inhibit GBM cell proliferation. Results Nearly 90% of patients showed at least one mutation in ion transport genes. GBM patients with mutations in sodium channels showed a significantly shorter survival compared to patients with no sodium channel mutations, whereas a similar comparison based on mutational status of calcium or potassium ion channel mutations showed no survival differences. Experimentally, targeting GBM cells with cardiac glycosides such as digoxin and ouabain demonstrated preferential cytotoxicity against U-87 and D54 GBM cells compared to non-tumor astrocytes (NTAs). Conclusions These pilot studies of GBM patients with sodium channel mutations indicate an association with a more aggressive disease and significantly shorter survival. Moreover, inhibition of GBM cells by ion channel inhibitors such as cardiac glycosides suggest a therapeutic strategy with relatively safe drugs for targeting GBM ion channel mutations. Key Words: glioblastoma multiforme, ion channels, mutations, small molecule inhibitors, cardiac glycosides.

Umbilical cord blood cells (UCBC) are a rich source of immature immune effector and accessory cells, including dendritic cells. UCBC-derived cytotoxic T lymphocytes (CTLs) generated against human breast cancer or neuroblastoma have shown an increased tumor-specific cytotoxicity compared to peripheral blood (PB)-derived CTLs. The precise mechanism of this increased cytotoxicity is not known. Since dendritic cells (DCs) play a central role in the immunostimulation, we compared the ultrastructure and antigen presenting nature of DCs from UCBC, PB and bone marrow (BM) at various stages of maturation using scanning and transmission electron microscopy as well as fluorescent microscopy to elucidate the mechanism underlying the increased cytotoxicity of UCBC-derived CTLs. DCs were examined for their immunophenotype nuclear morphology, dendritic processes and cytoplasmic endosomal vesicles after 0, 3, 7 and 10 days in culture with antigen priming on day 6. Results showed that there were smaller and more vesicles in UCB-DCs compared to DCs from the other two sources, while the endosomal vesicles in PB-DCs were heterogenous in size. The antigen processing ability of the UCB-DCs showed an increase in antigen-positive endosomes compared to PB-DCs as determined by the fluorescent microscopy. Thus, our results provided the comparative analyses of DCs from cord blood, peripheral blood and bone marrow, and suggested that UCBC-DCs might have better antigen presenting ability leading to increased CTL-mediated antitumor cytotoxicity.

In B-cell chronic lymphocytic leukemia (CLL), Rai stage, immunoglobulin gene mutational status, chromosomal abnormalities, CD38 and ZAP-70 expression were used as prognostic markers. In this study, to understand the molecular basis of chromosomal abnormalities leading to tumor progression, 90 CLL patients were grouped into poor prognosis (with 11q deletion and trisomy 12) and good prognosis (with normal karyotype and 13q deletion) and their clinical outcome was assessed. Gene expression profiles of 35 CLL samples with poor outcome (11q deletion, n=9; trisomy 12, n=5) and good outcome (13q deletion, n=13; normal karyotype, n=8) were analyzed using oligonucleotide microarray. Significance analysis of microarray (SAM) identified 27 differentially expressed genes between these two subgroups with significant overexpression of ATF5 and underexpression of CDC16, PCDH8, SLAM, MNDA and ATF2 in CLL patients with poor outcome. ATF5 gene expression in CLL was further studied because of its role in the regulation of cell cycle progression/differentiation and apoptosis. The overexpression of ATF5 was confirmed by real-time PCR using 39 CLL samples from the poor and good outcome groups. ATF5 was significantly (p<0.001) overexpressed in the poor outcome group. Furthermore, ATF5 expression was significantly higher in the 11q deletion as well as trisomy 12 group alone compared to the 13q deletion and normal karyotype groups. ATF5 overexpression was also associated with significantly (p=0.04) shorter time to treatment. Similarly, expression of five underexpressed genes also correlated with longer time to treatment. Thus, this report demonstrates that ATF5 may be one of the key genes involved in increased proliferation and survival in 11q deletion or trisomy 12, whereas CD16, CD86, SLAM, MNDA and ATF2 may be involved in the decreased proliferation of CLL cells with 13q deletion or normal karyotype.