The Role Of MAPK Signal Transduction And The Mutations Of N RAS And BRAF In Melanomas

Background In previous studies, the mutations of NRAS have been identified in 9-15% of cutaneous melanomas and the mutations of BRAF have been identified in 60-66% of cutaneous melanomas. And no NRAS and BRAF mutation was detected in uveal melanomas. But we don't know the mutations of NRAS and BRAF in nasal melanomas. So we study the mutations of NRAS and BRAF in nasal melanomas.Method:Extract the DNA from 12 fresh nasal melanomas and amplification by PCR,and then analysis the DNA sequence.Result:Mutations in NRAS were not detected in 12 cases,Mutations were detected in 1 of 8 cases. Conclution:The mutations rate of NRAS and BRAF in nasal melanomas is lower than that of cutaneous melanomas. Background The Ras-Raf-MAPKK-ERKpathway plays a central role in regulating the growth and survival of cells from the cutaneous melanomas,The high constitutive ERK activity in melanoma is most likely a consequence of mutations in NRAS and BRAF.In our previous studies, The mutations rate of NRAS and BRAF in nasal melanomas is lower than that of cutaneous melanomas. How about the activated ERK in nasal melanomas, we study the phosphorylated ERK protein in nasal melanomas.Method:We examined ERK activation in a total of 12 nasal melanoma samples by Western blot.Result:Western blot analyses revealed phosphorylated ERK protein in 8 of 12 (66%) of the nasal melanomas.Conclution:The constitutive ERK activity is one of the pathogenesis in nasal melanomas. Background:The constitutive activated ERK plays a central role in regulating the growth and survival of cells from the melanomas. The activated ERK plays a central role in many cellular responses mediated by Ras,and it plays a central role in many kinases activation (such as p90rsk1,MNK1,MNK2) and many transcription factors activation(such as Elk1,cEts1,c-Ets2). However,the activated ERK associated with melanoma proliferation is not well understood. We want to investigate the mechanism and effects of inactivated ERK on cell cycle.Method:We inhibit the downstream of MEK/ERK pathway by PD98059.The effect of inactivated ERK on cell cycle of melanoma cell line was evaluated by cell growth curve and MTT assay. Flow cytometric analysis was performed for cell cycle progression. Western blot was used to detect the expression of cyclin D1 and activated ERK. Result:A significant increase in G0-1 phases and a significant decrease in S phases was observed after the inhibition of MEK/ERK downstream. The cyclin D1 were not detected by western blot after the inhibition of MEK/ERK downstream.Conclution:The cell cycle was arrested in G0-1 by the inactivated ERK. The mechanism is the inhibition of cyclin D1 synthesis. Background:The constitutive activated ERK plays a central role in regulating the growth and survival of cells from the melanomas.The activated ERK plays a role in antiapoptosis in acute myeloid leukemia (AML).There is no report about the antiapoptosis effects of the ERK in melanoma. We want to investigate the antiapoptosis effects of ERK in melanomaMethods:The melanoma cell line A-375 were cultured in the 10%FBS or 1%FBS with PD98059 or serum-free or serum-free with PD98059 conditions. We check the melanoma cells apoptosis in four groups by flow cytometric analysis, and we compare the apoptosis rate in four groups.Result:There is no definite deference between 10%FBS without PD98059 and serum-free without PD98059 group in the cells apoptosis, But there is definite deference between 10%FBS with PD98059 and serum-free with PD98059 group in the cells apoptosis. Conclusion There is a antiapoptosis effects of the ERK in melanoma.