cAMP and PMA enhance the effects of IGF-I in the proliferation of endometrial adenocarcinoma cell line HEC-1-A by acting at the G 1 phase of the cell cycle

The present study was undertaken to determine whether endometrial cancer cell line HEC-1-A differ from nontransformed cells, in that the cAMP and protein kinase C pathways may enhance IGF-I effects in mitogenesis by acting at the G 1 phase of the cell cycle instead of G 0 . Immunofluorescence staining of HEC-1-A cells using the proliferating cell nuclear antigen (PCNA) monoclonal antibody and flow cytometric analysis determined that HEC-1-A cells do not enter the G 0 phase of the cell cycle when incubated in a serum-free medium. Approximately 51% of the cells were in G 1 , 12% were in S and 37% in G 2 phase of the cell cycle prior to treatment. Forskolin and phorbol-12-myristate 13-acetate (PMA) were used to stimulate cAMP production and protein kinase C activity, respectively. IGF-I, forskolin and PMA each increased ( P <0.01) [ 3 H]-thymidine incorporation in a dose and time dependent manner. The interaction of forskolin and PMA with IGF-I was then determined. Cells preincubated with forskolin or PMA followed by incubation with IFG-I incorporated significantly more ( P <0.01) [ 3 H]-thymidine into DNA than controls or any treatment alone. It is concluded that forskolin and, to a lesser extent, PMA exert their effect at the G 1 phase of the cycle to enhance IGF-I effects in cell proliferation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75013/1/j.1365-2184.1995.tb00061.x.pd

Differential interactions between IGFBP-3 and transforming growth factor-beta (TGF-β) in normal vs cancerous breast epithelial cells

In addition to modulating insulin-like growth factors action, it is now clear that insulin-like growth factor-binding protein-3 also has intrinsic effects on cell growth and survival. We have compared the effects of insulin-like growth factor-binding protein-3 and transforming growth factor-beta on cell proliferation and death of Hs578T cells and the normal breast epithelial cell line, MCF-10A. The growth of MCF-10A cells was inhibited at low concentrations of insulin-like growth factor-binding protein-3 but stimulated at high concentrations. These differential effects were unaffected in the presence of an insulin-like growth factor-I receptor antagonist. A synthetic peptide corresponding to the serine phosphorylation domain of insulin-like growth factor-binding protein-3 (that does not bind to insulin-like growth factors) also mimicked these differential actions. The growth of both cell lines was significantly inhibited by transforming growth factor-beta, this was associated with a 14-fold increase of insulin-like growth factor-binding protein-3 secreted by the Hs578T cells but a five-fold decrease of insulin-like growth factor-binding protein-3 secreted by MCF-10A cells. Replacement doses of exogenous insulin-like growth factor-binding protein-3 overcame the transforming growth factor-beta-induced growth inhibition in the MCF-10A cells. Cell death induced by ceramide was significantly reduced by insulin-like growth factor-binding protein-3 in the MCF-10A cells and depleting insulin-like growth factor-binding protein-3 with transforming growth factor-beta in these cells consequently increased their susceptibility to ceramide. In contrast, insulin-like growth factor-binding protein-3 enhanced apoptosis induced by ceramide in the Hs578T cells but transforming growth factor-beta treated Hs578T cells were resistant to apoptosis. The addition of anti-sense mRNA to insulin-like growth factor-binding protein-3 significantly abrogated this effect of transforming growth factor-beta. These data indicate that insulin-like growth factor-binding protein-3 has intrinsic activity capable of inhibiting or enhancing the growth and survival of breast epithelial cells depending on the cell line and exposure to other cytokines

Dermaval&trade; inhibits glucose-induced neutrophil elastase activity in healthy subjects

Tania Reyes-Izquierdo,1 Boris Nemzer,2 Ruby Argumedo,1 Cynthia Shu,1 Zb Pietrzkowski1 1Applied BioClinical Inc., Irvine, CA, 2FutureCeuticals Inc, Momence, IL, USA Background: Dermaval&trade; is a composite formulation of various phytochemical-rich plant materials as quantified using high-performance liquid chromatography. This blend exerts inhibitory activity on human neutrophil elastase (HNE). An acute, crossover clinical study was performed to assess the effects of Dermaval on glucose-induced HNE activity in 20 healthy subjects. Methods: Participants served as their own controls during this 3-day trial. On day 1, all study participants were fasted and given only 300 mL of water. Blood was drawn before treatment and 60 and 120 minutes post treatment. On day 2, participants were fasted, treated with 75 g of glucose, and similarly tested. On day 3, participants consumed a 50 mg serving of Dermaval followed by 75 g of glucose 15 minutes later. HNE concentration and HNE total activity were determined using enzyme-linked immunosorbent assay. Results: Average values for HNE activity in the control group (day 1) did not change. Treatment with a single dose of glucose (day 2) increased blood HNE activity by 175% over baseline levels (P=0.005) during the first 60 minutes. Pretreatment with Dermaval on day 3 prevented the glucose-induced increase in HNE activity (P=0.005 at 60 minutes and P=0.03 at 120 minutes versus respective day 2 values). Interestingly, ingestion of 75 g of glucose resulted in the same blood glucose levels on days 2 and 3, indicating that ingestion of Dermaval did not affect glucose absorption. Conclusion: These results suggest that Dermaval acutely inhibits glucose-induced HNE activity. Further investigations are needed to elucidate the direct and/or indirect mechanism of this effect and to verify whether treatment with Dermaval without glucose may acutely affect activity of HNE as well. Keywords: crossover study, human neutrophil elastase, glucos