Clopidogrel Plavix could facilitate cytotoxic drug damaged cells to undergo apoptosis. Furthermore, a recent study demonstrated that enzastaurin had a cooperative effect with gefitinib and was able to revert gefitinib resistance in cancer cells through the inhibition of Akt and VEGF pathways. These studies suggest that enzastaurin might be a promising novel agent in NSCLC patients. Enzastaurin inhibited the downstream PKCb signalling, PI3K/ AKT pathway and the phosphorylation of glycogen synthase kinase 3b. Anti tumour and anti angiogenic activity of enzastaurin was also demonstrated in tumour xenograft models, including NSCLC, and was confirmed using a standardised clonogenic assay in patient derived tumour explants. Significant chemical library screening reduction of VEGF protein levels following enzastaurin treatment, together with a significant decrease in intratumoural vessel density, has been demonstrated in vivo. In the current study using a RTKs phosphorylation antibody array, we found elevated levels of VEGFR2 and VEGFR3 in the enzastaurin sensitive cells. Our results are in agreement with previous data concerning enzastaurin and anti angiogenic activity. These findings demonstrated that lung cancer cases with activated angiogenic activity should respond to enzastaurin treatment.
In this study, using gene chip and pathway analysis, we identified 16 genes that nattokinase 133876-92-3 correlated with sensitivity to enzastaurin. Pathway analysis also revealed that JAK1 was the most important molecule affected by enzastaurin treatment of NSCLC. The JAK is a non RTK and can activate STAT3 transcriptional factor. The STAT3 is also persistently activated in about half of NSCLC tumours and is involved in tumour invasion, metastasis and angiogenesis through differential gene regulation. Increased levels of JAK1 and STAT3 were observed in the sensitive cells in this study. Knockdown of JAK resulting in p STAT3 also diminished the growth inhibitory effect of enzastaurin in the sensitive cells. In contrast, overexpression of JAK1 by lentiviralmediated production enhanced the drug sensitivity to tasocitinib enzastaurin in the sensitive cells. These results suggest that JAK expression levels can be used as predictive markers of enzastaurin sensitivity. Non small cell lung cancer patients with an activated JAK/STAT3 pathway are suitable cases for enzastaurin treatment. MicroRNAs are small non coding RNA molecules of about 20 nucleotides that are frequently located at chromosomal regions deleted or amplified in cancers, suggesting that miRNAs are a new class of genes involved in human tumourigenesis.
Recently, miRNAs have been demonstrated as diagnostic and prognostic markers in lung cancer. We previously reported that the inhibition of miR 21, whose upregulation is associated with EGFR mutations, can be a therapeutic strategy, either as a monotherapy or cisplatin in combination with EGFR TKI treatment. In this study, expression of miR 21 and its host gene, TMEM49, were significantly higher in enzastaurin sensitive cells than in enzastaurinresistant cells. In addition, a significant positive correlation was observed between miR 21 and JAK1. The STAT3 reportedly signals IL 6 induced upregulation of miR 21 in multiple myeloma cells. We confirmed that JAK1 and its downstream target STAT3, containing three binding sites of miR 21 promoter.