Analysis of intracellular signaling The interference selleckbio of RAD001, AEE788 or VPA with intracellular signaling was investigated. VPA diminished EGFr, pERK and phosphorylated p70S6k in all cell lines. Analysis of pAkt revealed conflicting results, since this protein was dis tinctly reduced in DU 145, strongly enhanced in LNCaP, whereas a protein double band appeared in PC 3 cells. Both, pEGFr and pERK were down regulated in all tumor cells following AEE788 exposure, but pp70S6k expression was similar between treated and untreated cells. The latter was also true with respect to pAkt. RAD001 reduced pEGFr in PC 3 and LNCaP and pERK in PC 3 and DU 145 cells. RAD001 also down regulated pp70s6 k in all explored cell lines. Triple drug treatment provided combinatorial benefit with respect to EGFr, pEGFr, pERK and pp70S6k loss.
Furthermore, the amount of pAkt proteins was greatly but not in PC 3 cells. Cyclin E was elevated by VPA but reduced by AEE788. RAD001 profoundly altered cyclin B in DU 145 but not in PC 3 and LNCaP cells. Several investigators have recently demonstrated that a tumor cells response to a particular drug depends on receptor and protein configuration, which is characteristic in the different PC cell lines. It has been shown that the PC phenotype determines its sensitivity towards treatment with a tyrosine kinase inhibitor, mTOR or HDAC inhibitor. The variable response of the cell lines to a single drug treatment is not foreseeable, due to the PCs heteroge neous nature, resulting in different malignant matura tion pathways and protein profiling.
Analysis of mTOR in PC patients revealed distinct heterogeneity in the study cohort. The same was true with respect to EGFr and VEGF expression, and to the HDAC level. Given the molecular specificity of each targeted compound, it is unrealistic to expect similar biochemical reactions in every PC cell line. The data presented here demonstrate that the triple drug combination circum vents this problem by exerting anti cancer properties in different tumor cell types according to the particular molecular profile. From a clinical viewpoint, simulta neous use of a set of drugs with complementary phar macological characteristics may enhance the total percentage of responders, as well as the elimination rate of tumor clones in each individual patient.
The VPA RAD001 AEE788 drug combination diminished cdk1, cdk2, cdk4 and cyclin B in PC 3, DU 145 and LNCaP elevated in PC 3 and LNCaP cells, exceeding Cilengitide the pAkt levels evoked by single drug use. pEGFr down regulation induced by single drug treatment in PC 3 and LNCaP cells was reverted by the triple drug application. Discussion The combined inhibition of EGFr VEGFr and mTOR related pathways, coupled with HDAC deactivation, pro foundly blocked PC growth and adhesion. The blocking effect was similar in all employed cancer cell lines and more extensive, compared to the single drug regimen.