Patterns of reactivity with anti-glycolipid antibodies in human primary brain tumors

Elevation of sulfatides in ovarian cancer: an integrated transcriptomic and lipidomic analysis including tissue-imaging mass spectrometry

Background

Sulfatides (ST) are a category of sulfated galactosylceramides (GalCer) that are elevated in many types of cancer including, possibly, ovarian cancer. Previous evidence for elevation of ST in ovarian cancer was based on a colorimetric reagent that does not provide structural details and can also react with other lipids. Therefore, this study utilized mass spectrometry for a structure-specific and quantitative analysis of the types, amounts, and tissue localization of ST in ovarian cancer, and combined these findings with analysis of mRNAs for the relevant enzymes of ST metabolism to explore possible mechanisms.

Results

Analysis of 12 ovarian tissues graded as histologically normal or having epithelial ovarian tumors by liquid chromatography electrospray ionization-tandem mass spectrometry (LC ESI-MS/MS) established that most tumor-bearing tissues have higher amounts of ST. Because ovarian cancer tissues are comprised of many different cell types, histological tissue slices were analyzed by matrix-assisted laser desorption ionization-tissue-imaging MS (MALDI-TIMS). The regions where ST were detected by MALDI-TIMS overlapped with the ovarian epithelial carcinoma as identified by H & E staining and histological scoring. Furthermore, the structures for the most prevalent species observed via MALDI-TIMS (d18:1/C16:0-, d18:1/C24:1- and d18:1/C24:0-ST) were confirmed by MALDI-TIMS/MS, whereas, a neighboring ion(m/z 885.6) that was not tumor specific was identified as a phosphatidylinositol. Microarray analysis of mRNAs collected using laser capture microdissection revealed that expression of GalCer synthase and Gal3ST1 (3'-phosphoadenosine-5'-phosphosulfate:GalCer sulfotransferase) were approximately 11- and 3.5-fold higher, respectively, in the ovarian epithelial carcinoma cells versus normal ovarian stromal tissue, and they were 5- and 2.3-fold higher in comparison with normal surface ovarian epithelial cells, which is a likely explanation for the higher ST.

Conclusions

This study combined transcriptomic and lipidomic approaches to establish that sulfatides are elevated in ovarian cancer and should be evaluated further as factors that might be important in ovarian cancer biology and, possibly, as biomarkers.

Role of Endogenous Neural Stem Cells in Neurological Disease and Brain Repair

These examples show that stem-cell-based therapy of neuro-psychiatric disorders will not follow a single scheme, but rather include widely different approaches. This is in accordance with the notion that the impact of stem cell biology on neurology will be fundamental, providing a shift in perspective, rather than introducing just one novel therapeutic tool. Stem cell biology, much like genomics and proteomics, offers a "view from within" with an emphasis on a theoretical or real potential and thereby the inherent openness, which is central to the concept of stem cells. Thus, stem cell biology influences many other, more traditional therapeutic approaches, rather than introducing one distinct novel form of therapy. Substantial advances have been made i n neural stemcell research during the years. With the identification of stem and progenitor cells in the adult brain and the complex interaction of different stem cell compartments in the CNS--both, under physiological and pathological conditions--new questions arise: What is the lineage relationship between t he different progenitor cells in the CNS and how much lineage plasticity exists? What are the signals controlling proliferation and differentiation of neural stem cells and can these be utilized to allow repair of the CNS? Insights in these questions will help to better understand the role of stem cells during development and aging and the possible relation of impaired or disrupted stem cell function and their impact on both the development and treatment of neurological disease. A number o f studies have indicated a limited neuronal and glial regeneration certain pathological conditions. These fundamental observations have already changed our view on understanding neurological disease and the brain's capacity for endogenous repair. The following years will have to show how we can influence andmodulate endogenous repair nisms by increasing the cellular plasticity in the young and aged CNS.

Cytogenetic analysis of gemistocytic cells in gliomas

Gemistocytes are glial cells characterized by voluminous, eosinophilic cytoplasm and a peripherally positioned, often flattened nucleus. Gemistocytes, usually present in anoxic-ischemic brains, are regularly encountered in glial neoplasms. The presence of gemistocytes in gliomas has been associated with an unfavorable clinical course, notwithstanding the low proliferative potential of these cells. It is not known whether gemistocytes residing in gliomas are dormant tumor cells, or alternatively, represent interspersed reactive glial cells. Whereas gemistocytic astrocytomas have been subject to various genetic investigations, no genomic analysis comparing individual cells in gliomas has been reported so far. In the present study, 3 astrocytomas, 3 oligodendrogliomas, and 3 mixed oligoastrocytomas, all harboring gemistocytic cells, were genetically analyzed by DNA in situ hybridization to paraffin-embedded, formalin-fixed tissue samples with optimal preservation of cellular morphology. To this end, probes for the centromeric regions of chromosome 7 and 10, known to show copy number aberrations in gliomas, were used. In addition, probes for centromeric regions of chromosomes 1 and 17 were used for the ploidy status of the tumors. The spot counts for the various chromosomes were statistically compared. Gains of chromosome 7 were found in 1 anaplastic astrocytoma, 1 anaplastic oligodendroglioma, and 1 anaplastic oligoastrocytoma. Loss of chromosome 10 was seen in 2 anaplastic astrocytomas, in 1 anaplastic oligodendroglioma, and in 1 anaplastic oligoastrocytoma. In 3 cases, significant differences in spot distributions between gemistocytes and non-gemistocytes were found, but the other cases showed no difference in spot distribution. It is concluded that, although many gemistocytic cells in gliomas may be considered reactive cells, in a subset of tumors, part of the gemistocytic cells should be considered neoplastic.

Ganglioside composition of a mouse brain tumor grown in the severe combined immunodeficiency (SCID) mouse

The content and composition of gangliosides were examined in an experimental mouse brain tumor, EPEN, that was grown subcutaneously in the flank of the syngeneic C57BL/6J (B6) host and in the B6 severe combined immunodeficiency (SCID) host. SCID mice lack functional T- and B-lymphocytes, but have a normal complement of macrophages. The content and distribution of the brain tumor gangliosides were similar whether the tumor was grown in the immunocompetent B6 host or in the B6-SCID host. N-acetylneuraminic acid- (NeuAc) containing GM3 was the major ganglioside in the subcutaneous tumors and in the cultured EPEN cells. Significant amounts of N-glycolylneuraminic acid- (NeuGc) containing gangliosides were found in the tumor grown in both mouse hosts. NeuGc-containing gangliosides are not expressed in normal mouse brain, but are present in macrophages and serum. An extremely complex pattern of minor gangliosides was found in the subcutaneous tumors on two-dimensional, high-performance thin-layer chromatograms. Most of the minor gangliosides comigrated with those found in mouse macrophages. The results show that the absence of functional T- and B-lymphocytes does not markedly affect brain tumor ganglioside composition and suggest that NeuGc-containing gangliosides in the EPEN can be derived from tumor infiltrating host cells (mostly macrophages) and from the extracellular milieu (serum).

Usefulness of a mouse myelin basic protein promoter for gene therapy of malignant glioma: myelin basic protein promoter is strongly active in human malignant glioma cells

We have searched for suitable promoters to regulate the expression of suicide genes for use in gene therapy. We have shown that the 1.3-kb fragment of the mouse myelin basic protein (MBP) promoter region initiates transcription in mouse glioma cells more efficiently than glial fibrillary acidic protein (GFAP) or myelin proteolipid protein (PLP) promoter. Among three different lengths of the MBP promoter, the shortest (256-bp) core promoter region initiates transcription as efficiently as 650-bp or 1.3-kb MBP promoter lengths in RSV-M glioma cells. To assess the suitability of the MBP promoter for use in clinical trials of malignant glioma gene therapy, we also had to show that it (the 1.3-kb length in this case) is effective in human glioma cells, as well as in murine glioma cells. The activity of the MBP promoter is much higher than that of GFAP or PLP promoter in most human glioma cells, suggesting that the MBP promoter would be best for directing toxic gene expression in gene therapy for patients with malignant glioma. Human glioma cells in which the MBP promoter was strongly active were sensitive to ganciclovir when they were transduced with MBP promoter/herpes simplex virus thymidine kinase gene-bearing retroviruses. In conclusion, retrovirus-targeted gene therapy for malignant glioma using this MBP promoter is a promising candidate for clinical trials.

Glycolipids and myelin proteins in human oligodendrogliomas

We studied myelin proteins and glycolipids in 24 human oligodendrogliomas (16 pure, eight mixed), including two grade I, 13 grade II, five grade III, and four grade IV. Tumours with a 1b ganglioside content (GD1b, GT1b and GQ1b) over 30% of total gangliosides occur more frequently in the WHO grade I and II (47%) and grade III (40%) than in the grade IV (25%) group; there was no difference in the amounts of total ganglioside or individual gangliosides between pure and mixed oligodendrogliomas. The presence of 6'-LM1 correlated with higher grades of tumours (chi 2 P approximately 0.02); however, 3'-LM1 and total neolacto-series gangliosides did not correlated with grade. Immunohistochemical studies of oligodendrocyte and myelin markers (GalCer, sulfatide, 2',3' -cyclic nucleotide phosphodiesterase, myelin basic protein and proteolipid protein) using specific antibodies showed only a very small proportion of tumour cells staining. These data do not support the hypothesis that tumours classified as oligodendrogliomas are derived from mature oligodendrocytes.