Aktivitätsverhalten von ERK1 und 2 in MG-63 Osteosarkomzellen unter dem Einfluß von Inhibitoren bei mechanischer Belastung

By signal transduction due to mechanical loading the signal cascade from MG-63 osteosarcoma cells was investigated. By inhibitors like BAPTA AM (calcium chelator), Gö 6976 (inhibitor of the calcium dependent PKC by using certain concentrations) and Gö 6983 (inhibitor of the PKC except of the µ-isoform by using certain concentrations) and mechanical loading the behavior of ERK1 and 2 activation was analyzed and it was tried to find out which isoform of the PKC contributes to the signal transduction. An MTT-cell proliferation assay showed through mechanical loading of the 5-th cell passage of MG-63 osteosarcoma cells with 4000µstr, 1Hz and 30 cycles that the cells were mechanosensitive because of increased proliferation of about 28,48%. Exclusive stretching the cells with 4000µstr, 1Hz and 30 cycles showed an ERK1 and 2 activation of the 3-rd and the 12-th cell passage with a maximum after 1min of the 3-rd cell passage and a maximum after 15min of the 12-th cell passage. Because of the fast (1min) and slow (15min) time of signal transduction there are calcium dependent and calcium independent signal cascades supposed. Surprisingly the 9-th cell passage showed a down regulation of the ERK1 and 2 activity with a minimum of 2min after stretching. Treatment of the cells with BAPTA AM, Gö 6976 and Gö 6983 demonstrated a paradoxical activation of ERK1 and 2. Treatment of the 6-th cell passage with Gö 6983 before mechanical loading resulted in an activation of ERK1 and 2 but the activation decreased by increasing concentration of Gö 6983. By contrast the 9-th cell passage showed an inverse behaviour with an activation of ERK1 and 2 by the increase of concentration of Gö 6983.