Study On The Screen And Their Action Mechanism Of Anticancer Drug Based On Targeting Protein Kinases

Many antitumor drugs were found low efficiency with superior side effect and difficultly to develop into chemotherapy drugs. Therefore, it is necessary to seek for new substitute drugs with high effect and low toxicity and high selectivity. Researches on target-based anticancer agents are now taken enthusiastically. Drug development based on targeting protein kinases is increasingly becoming an attractive strategy, however this kind of anticancer drugs are still rare in clinical application at present.Extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases (MAPKs) pathway is one of the most important pathways for cell proliferation, which is strongly linked with tumorigenesis and progression. Hence ERK MAPKs signaling pathways was taken as a target to screen high selective antitumor compounds by determining the inhibitory effect on the cellular proliferation and the function mechanism was investigated additionally.In this work, prostate cancer (PC3) cells and NIH3T3 cells were contributed to the compounds at different concentration, which was subject to Western Blot(WB) Immunoprecipitation(IP) assay to determine the inhibitory mechanism of the signal transduction cascade and check the target protein. In addition, anti-tumor activity of investigated compounds was determined by MTT and SRB assays.In the present work, a series synthesized 4-amidoquinazoline derivatives, A001, A003, A007, A010 and A011 show strong inhibitory activity on the phosphoralation of EGFR. The efficient concentration of them was uniformly under 0.5μM (and 5μM for A007) and the block time is less than 10 minutes.These results suggested that the compounds mediated EGFR phosphorylation by direct inhibition on the EGFR instead of the dephosphorylation by anti-phosphotyrosine.It was founded that the synthesized compound GuTu01 inhibited the total protein phosphrylation inside NIH3T3 cells by inhibiting the phosphrylation of PDGFR (Platelet Derived Growth Factor receptor). The block concentration of GuTu01 was 10μM as showed in the WB assay. And the result of MTT and SRB show that GuTu01 inhibited the proliferation of PC3 with IC50 value of 0.53μM (superior to the typical curcumin with IC₅₀ of 2.0μM) and BGC823 with IC₅₀ value of 0.93μM respectively.One of hydroxyanthraquinones, purified from Chinese medicinal herb rhubarb, emodin was found to block the ERK phosphorylation of PC3 cells at 20uM. And two other compounds had potent proliferation inhibitory activity on A431 and PC3 cells at 20μM along with no effect on PDGF stimulated ERK phosphorylation, and the inhibition rate on the proliferation of PC3 cells and A431 cells was 73.6% and 63.4% respectively as determined by MTT and SRB assays. The results suggest that these compounds are biologically active and may lead to development of anticancer drugs with high activity and selectivity.