Mary Ann Repman

Density-Dependent Changes in Gangliosides and Sialidase Activity of Murine Neuroblastoma Cells

Abstract: Density‐dependent changes in ganglioside composition, Vibrio cholerae neuraminidase (VCN)‐susceptible sialyl residues, and membrane‐ associated sialidase activity were determined for the cholinergic murine neuroblastoma cell line S20Y. A decrease in total ganglioside sialic acid and VCN‐releasable sialic acid was observed with increasing cell density. GM3 was the major ganglioside component of preconfluent S20Y cells, whereas GDIA was predominant in postconfluent cells. Sialidase activity increased in confluent and postconfluent cells and may account for the reduction in total ganglioside sialic acid observed with increasing cell density. In contrast, while adrenergic N115 cells showed a decrease in VCN‐susceptible sialic acid residues with increasing cell density, there was no significant change in ganglioside composition or ganglioside sialic acid levels.

Ganglioside composition of human neuroblastomas. Correlation with prognosis. A Pediatric Oncology Group Study.

The ganglioside composition of neuroblastoma samples from 53 patients was determined. Tumor sites included the adrenals (15), and the thoracic (20), abdominal (15), and pelvic (3) areas. Age of the patients at the time of surgery ranged from 1 day to over 10 years and the Stage of the tumors from A to D. Differences in ganglioside patterns were observed, with neuroblastomas from patients who were either disease positive or dead of disease tending to have more monosialogangliosides and fewer gangliotetraose gangliosides of the B series than tumors from patients who were disease‐free. More specifically, six of the seven patients lacking GT1b died of disease, suggesting that the absence of GT1b is indicative of a poor prognosis.

Cell culture of sixteen‐day‐old rat embryo cerebra and associated changes in ganglioside pattern

THE GANGLIOSIDE composition of neurons (essentially neuronal perikarya) and glia prepared using bulk isolation techniques has been reported to be similar to that obtained for whole brain (ABE & NORTON, 1974; HAMBERGER & SVENNERHOLM, 1971). In contrast, mouse neuroblastoma cells (often used as a possible model for neurons) and glioma cells grown in uitro have simplified ganglioside patterns. The neuroblastoma cells lack trisialoand sometimes disialogangliosides (SCHENGRUND & NELSON, 19766; STOOLMILLER et a!., 1973) and the glioma cells have only hematoside (STOOLMILLER et al., 1973). Bulk preparations of neuronal perikarya, and neuroblastoma and glioma cells grown in uitro, all have low levels of ganglioside-sialidase (EC 3.2.1.18 neuraminidase, N-acetylneuraminosyl glycohydrolase) activity relative to that of mature brain (SCHENGRUND & NELSON, 1976a, 6). This study was done to determine whether nontransformed brain cells dissociated from rat embryo cerebra and grown in uitro displayed the ganglioside pattern characteristic of these cells in the CNS, and an increasing sialidase activity, as they differentiate morphologically in uitro.

A biochemical analysis of thoracic neuroblastomas: a Pediatric Oncology Group study.

A biochemical analysis was performed on tumor tissues from 20 patients who presented with thoracic neuroblastomas. Nine patients were under 1 year of age at the time of diagnosis, and 12 patients had stage A disease. Eighteen of the 20 patients are disease free with a mean follow-up of 5 1/2 years. The ganglioside composition of the tumor tissue was investigated, since these cell membrane components have been proposed to play a role in cell to cell interaction and may be altered on cell transformation. In addition, the ganglioside composition of the central nervous system changes with maturation. Previous studies in children with neuroblastoma have shown that tumor tissue containing more complex gangliosides is associated with a better prognosis. Neuroblastomas from patients with thoracic primaries were found to contain more complex gangliosides of the b series (GD1b, GT1b) and fewer monosialogangliosides, suggesting a more differentiated cellular composition. Tissue from one of the thoracic patients who died lacked GT1b. The absence of this ganglioside has proven to be an indicator of a poor prognosis. Four specimens contained no detectable GD2, which is thought to be a specific marker for neuroblastomas. These data suggest that the improved prognosis seen with thoracic neuroblastomas is due to a basic biologic difference within these tumors, and this finding should be taken into consideration when planning therapy.

DIFFERENTIAL ENRICHMENT OF CELLS FROM EMBRYONIC RAT CEREBRA BY CENTRIFUGAL ELUTRIATION

—Centrifugal elutriation was used to obtain different populations of cells dissociated from 16‐day‐old rat embryo cerebra. The cell populations recovered were viable and could be maintained for several weeks in vitro. Sterile conditions were maintained throughout a preparation. Rat pups were removed by Caesarean section, the cerebra dissected and the cells dissociated by brief exposure to trypsin (0.125%, 6 min). An equivalent volume of elutriation medium (Dulbeccos medium containing 1% fetal calf serum, sodium bicarbonate, penicillin and streptomycin, EDTA, and deoxyribonuclease) was added to the trypsin‐cell suspension, the dissociated cells pelleted, resuspended in elutriation medium and counted. Up to 4 x 108 cells were injected into the previously sterilized elutriator. Seven fractions were usually recovered from a preparation. The first fraction contained primarily red blood cells and cell debris, which could not be maintained in vitro. Upon culture, fraction 2 consisted of predominantly non‐neuronal cells, while fractions 3–6 contained neuronal and non‐neuronal cells. The morphological characteristics of the neurons differed in these fractions. Fraction 7 contained cells that had reaggregated during the elutriation procedure and exhibited a variety of cell types in vitro.

Response of mature mice to challenge with neuroblastoma after inoculation with neuroblastoma cells as neonates

Injection (s.c.) of 2 X 10(5) S20Y neuroblastoma cells into adult A/J strain mice regularly produced a higher incidence of progressive, lethal tumor growth. In contrast, successful tumor growth was significantly less frequent (P less than 0.001) when the same number of tumor cells were injected into neonatal A/J mice. A significant number (P less than 0.001) of matured mice that had rejected the initial S20Y cell inoculum as neonates were able to reject 2 subsequent challenges with S20Y cells.