Regulation of metastatic ovarian cells in serum-free medium by epidermal growth factor and transferrin

Development and characterization of a human ovarian cancer cell line which clones without agar in vitro

A new human ovarian cancer cell line has been initiated which clones without agar in vitro. The cell line has been characterized by growth of a tumor resembling the primary tumor in a nude mouse, by human lactic dehydrogenase isozyme pattern, by human karyotype, and by lack of contamination by other cell lines. Initial studies have demonstrated the presence of epidermal growth factor receptors in this cell line. The utility of this line for clonogenic studies is demonstrated by dose-response studies with doxorubicin, cisplatinum, and 13-cis-retinoic acid.

Effect of transferrin on alkaline phosphatase activity and collagen synthesis in osteoblastic cells derived from newborn mouse calvaria

The effect of transferrin was tested on osteoblastic cells (clone MC3T3-E1) cultured in serum-free medium containing 1% bovine serum albumin (BSA). Transferrin (Tf) stimulated increases of protein content and protein synthesis, but not of DNA content and cell number, in the cells. This protein also increased alkaline phosphatase activity and collagen synthesis in combination with 1% BSA. Actinomycin D and cycloheximide inhibited alkaline phosphatase activity induced by Tf, suggesting that Tf may enhance de novo synthesis of the enzyme. These results indicate that Tf may be involved in differentiation of osteoblastic cells, but not in their proliferation, in vitro.

Hyperandrogenism, insulin resistance, and acanthosis nigricans syndrome: a common endocrinopathy with distinct pathophysiologic features

The HAIR-AN syndrome that consists of hyperandrogenism (HA), insulin resistance (IR), and acanthosis nigricans (AN) is an underdiagnosed endocrinopathy, because hyperandrogenic women are not commonly screened for insulin resistance or acanthosis nigricans. The distinct pathophysiologic features of the HAIR-AN syndrome are discussed in detail. In this syndrome, the primary pathophysiologic derangements are the insulin resistance and the hyperandrogenism. The acanthosis nigricans is an epiphenomenon of these primary processes. In patients with the HAIR-AN syndrome, the degree of severity of the insulin resistance is positively correlated with the degree of severity of the hyperandrogenism. In patients with adequate pancreatic beta-islet cell reserve, insulin resistance results in a long-term increase in circulating insulin levels. The hyperinsulinemia probably directly stimulates ovarian androgen production. In turn, hyperandrogenism itself produces insulin resistance. This positive feedback loop between insulin resistance and hyperandrogenism propagates the disease, and increases its severity over time. The relationship between insulin resistance and hyperandrogenism may explain the hyperandrogenemia seen in the following disease processes: obesity, acromegaly, lipoatrophic diabetes, leprechaunism, and Kahn types A and B insulin resistance.

Age-dependent requirements of sympathetic neurons in serum-free culture

Neurons dissociated from chick sympathetic ganglia of different embryonic ages can be cultured equally well in serum containing or serum-free (N1) medium on collagen polyornithine, and polyornithine pretreated with neurite-promoting factor (PNPF), in the presence of nerve growth factor (NGF). Quantitative analysis of nerve cell survival is best achieved in serum-free conditions and on PNPF-pretreated polyornithine. Under such conditions, 11-day embryonic (E11) sympathetic neurons showed a specific requirement for insulin, selenium and transferrin. Similar analyses at E8 and E16 revealed that the requirement for transferrin is developmentally regulated since it is not expressed by E8 nerve cells until after 3 days in vitro. These data strongly suggest that, besides NGF, other specific molecules are involved in the control of neuronal survival and that specific requirements may be displayed at different embryonic stages.