Basic calcium phosphate (BCP) crystals control the traverse of cells from the G0-G1 to S-phase of the cell cycle and initiate proliferation by rendering fibroblasts competent to respond to insulin-like growth factors in plasma. The present study examines whether BCP crystals induce transcription of the protooncogenes c-fos and c-myc and the effect of β-interferon (IFN-β) on protooncogene transcription as well as BCP crystal-induced DNA synthesis. Stimulation of density-arrested BALB/c-3T3 cells with either BCP crystal or platelet-derived growth factor (PDGF) results in maximal accumulation of c-fos mRNA at 30 min after stimulation. Induction of c-myc transcription by BCP crystal or PDGF occurs within 1 h and is maximal at around 3 h after stimulation. Simultaneous addition of IFN-β with either BCP crystals or PDGF had little effect on c-fos induction but delayed both c-myc message accumulation and entry into S phase. The delay in c-myc message induction after IFN-β treatment cannot account for the observed delay in the onset of DNA synthesis, since IFN-β can be added at up to 6 h after stimulation with either PDGF or BCP crystals, and a similar delay in the onset of DNA synthesis is still observed.
|Original language||English (US)|
|Number of pages||5|
|State||Published - Jan 1 1989|
ASJC Scopus subject areas
- Cancer Research