Zinc Deprivation of Murine 3T3 Cells by Use of Diethylenetrinitrilopentaacetate Impairs DNA Synthesis upon Stimulation with Insulin-Like Growth Factor-I (IGF-I)

Abstract

Growth failure in zinc-deficient animals is associated with decreased DNA synthesis; zinc deprivation of 3T3 cells, by use of diethylenetrinitrilopentaacetate (DTPA), impairs thymidine incorporation when the cells are stimulated with fetal bovine serum (FBS). The purpose of this study was to determine the step of cell cycle progression that is affected by zinc deprivation. Swiss murine 3T3 cells were cultured for 3 d in complete media and then for 2 d in low serum media. Cells were then placed in serum-free media and stimulated in sequence with platelet-derived growth factor (PDGF; 3 h), epidermal growth factor (EGF; 0.5 h) and insulin-like growth factor-I (IGF-I; 16 h). The combination of growth factors stimulated thymidine incorporation to the same extent as 10% FBS, and DTPA or EDTA (0.6 mmol/L) inhibited thymidine incorporation. Inhibition was prevented by addition of zinc, but not calcium, iron or cadmium (0.4 mmol/L). When DTPA was present during all stages with no addition of zinc, or zinc added during the competency-priming (PDGF and EGF) step, the IGF-I step, or both steps, the zinc effect occurred at the IGF-I step. Zinc addition 4 h before the measurement of thymidine incorporation had no ameliorative effect, but the presence of zinc during the prior 12 h increased incorporation. Thus zinc exerts its major effect on DNA synthesis during the IGF-I stimulatory phase of the cell cycle. The total zinc concentration of 3T3 cells treated with DTPA for 16 h was not different from that of untreated cells; hence only a small compartment of the cell is affected by DTPA.

Structural characterization of the zinc binding domain in cytosolic PSD‐95 interactor (cypin): Role of zinc binding in guanine deamination and dendrite branching

“…In our cellfree zinc-binding assay, the source of zinc that was incorporated into the proteins during bacterial culture growth was obtained from yeast extract used in the LB media (0.2 mM 18 ). This is a much higher concentration of that found in the media used to grow COS-7 cells for guanine deaminase assays (5 µM from the fetal bovine serum 19,20 ). It is unknown the concentration range of cellular zinc that is needed for cypin's effect on dendrite branching.…”

Zinc Released from Injured Cells Is Acting via the Zn2+-sensing Receptor, ZnR, to Trigger Signaling Leading to Epithelial Repair

“…The effect of Zn 2ϩ in enhancing cell proliferation is synergistic with intracellular Ca 2ϩ rise, indicating that their effects are mediated through a common pathway (26,27). Importantly, Zn 2ϩ affects cell proliferation rate prior to changes in its intracellular levels, suggesting that the extracellular Zn 2ϩ pool mediates signaling leading to epithelial repair (28).…”

Role of metal‐responsive transcription factor‐1 (MTF‐1) in EGF‐dependent DNA synthesis in primary hepatocytes

“…It has been reported that, when cells are cultured in media containing an extracellular chelator, such as EDTA or DTPA, growth factor-induced DNA synthesis is impaired [MacDonald et al, 1998;Lefebvre et al, 1999]. There are six zincfingers of the C 2 H 2 type in the structure of MTFDC.…”