In melanocytes, phosphor ylation patterns conformed to people anticipated with the canonical kinase substrate relationships. Notably, mela nocytes showed a consistent serum dependent phos phorylation standing of growth aspect signalling pathway proteins. selleck chemical Having said that steady pattern of phosphorylation was not seen in melanoma cell lines. Our stu dies are in line with latest findings which indicate that in neoplastic cells, the exercise of signalling pathways does not usually correlate together with the mutational standing of upstream proteins specially while in the MAPK pathway. This heterogeneity in signalling phenotype is consistent using the large degree of variability in the patterns of gene expression observed in these melanoma cell lines. Earlier studies have proven that PIK3CA mutations can cause hyperactivated PI3K signalling pathways. However, this phenomenon was not continually observed in all NZM cell lines studied.
Our success are just like that of Morrows et al,who observed different order Rigosertib patterns of signalling in colon tumour cell lines harbouring the same mutation. They may be also consistent with research by other groups inside a variety of non melanoma cell lines. A degree of com plexity is offered through the success of a current examine of MCF 7 cells,during which all of the sublines produced from the parental MCF 7 cell line had been all anticipated to possess exactly the same PIK3CA mutation, but not all of the sub lines showed strong PKB phosphorylation. The results suggest that to some extent the signalling phenotype is usually independent of genotype. All NRAS only mutant cell lines showed serum inde pendent phosphorylation of ERK1 two in spite of no observa ble phosphorylation of MEK1 2. The results are surprising but are steady with the observation of Pratilas et al,who found that ERK phosphorylation was not indicative of signalling through the MEK path way, as ERK phosphorylation is also regulated by nega tive feedback loops.
Furthermore, ERK1 two is phosphorylated despite small MEK1 2 phosphorylation in some NZM cell lines, suggesting MEK independent reg ulation of ERK. It has been suggested that PI3K and classical protein kinase C play a major part within the MEK independent prolonged activation of ERK in some cell kinds. As the many NZM cell lines utilized in this study are mutant for both BRAF or NRAS, this suggests that these oncogenic mutations confer activa tion of your MAPK pathway. However, the dominant sig nalling pattern observed in every one of the NZM cell lines is serum independent phosphorylation of ERK1 2 com pared to melanocytes. We also didn’t observe NZM cell lines lacking PTEN perform to become strongly asso ciated with inactivation of MEK1 2 and ERK1 2 in the MAPK pathway as noted by Dan et al.