This is not surprising, thinking about the cell lines utilised are distinctive in terms of their genetic back ground and oncogenic mutations that happen to be existing in these cells. By way of example, in accordance to your Sanger institute COS MIC database, MCF7 cells exhibit a mutation inside the catalytic subunit of PI3K, whereas SKBR3 cells have a WT PI3K. Nevertheless, each cell lines express non mutated EGFR and Ras proteins. Yet another element that may have an impact on the results obtained in different research certainly is the signifies of knocking down flotil lin expression. For example, Lin et al. described that flotillin 1 knockdown in MCF7 cells reduces cell viability and impairs tumorigenicity in MCF7 cells. In contrast to these data, we right here observed elevated MAPK signaling and enhanced cyclin D mRNA expression on flotillin 1 ablation.
Furthermore, Lin et al. detected a decreased AKT phosphorylation and concomitant upregulation of the forkhead transcription factor Foxo3 which is associ ated with decreased cell viability as a consequence of upregulation of apoptotic genes. While Foxo3 expression was in creased in our flotillin one knockdown cells, we did not observe any evident impairment of AKT activation, in contrast to Lin et al. kinase inhibitor inhibitor screening Seeing that AKT action negatively has an effect on Foxo3 function by means of a direct phosphorylation, its plausible that the greater Foxo3 expression in flotillin knockdown cells is compensated from the regular AKT activity, so stopping Foxo3 from growing cell death in these cells. Even further much more, PI3K mutations have already been shown to promote resist ance towards apoptosis and may well thus defend towards increased Foxo3 exercise.
There is one particular vital distinction in the experimental setting as compared to our Mubritinib review. Lin et al. apparently employed a short phrase, acute knockdown of flotillins, whereas we have right here created steady flotillin knock down MCF7 cell lines. We feel that the secure knock downs are much more representative with the predicament in tumors, as adaptation to flotillin deficiency may perhaps result in compensatory upregulation of signaling proteins, as proven inside the existing study, which will not be potential on acute knockdown. In line with this particular, Berger et al. lately showed that though flotillin 2 deficiency inside a mouse breast cancer model triggered a reduced lung metasta sis formation, it showed no effect around the development of key tumors. Similarly, we have now detected an upregulation of MAPK signaling and expression of a number of growth related genes in numerous organs of our flotillin two knockout mouse model generated independently of that of Berger et al. So, long lasting effects of flotillin abla tion might be unpredictable resulting from compensatory mecha nisms, particularly in cancer patients. We’ve got thus far only observed the upregulation of EGFR in MCF7 cells upon steady flotillin depletion.