Adherent cells, such as those found in epithelial tissues, must be physically associated with extracellular matrix (ECM)components to survive. Though stimulation by growth factors is an essential factor in cell survival, normal cells also requires cell adhesion to ECM proteins. The cessation of these anchorage-mediated signals seems to be a common mechanism to physiolog ically t erminate t he l ife cycle of t hese c ells b y apoptosis. This form o f cell death has been termed anoikis.In cancer, resistance to anoikis of cancer cell is important in invasion and metastasis. The present study investigated the intracellular mechanism involved in anoikis, especially in cells treated with epigallocatechin- 3-gallate(EGCG). To induce anoikis, cell culture plates were coated with 10 ㎍/ml poly-HEMA. A549 lung adenocarcinoma cells were grown in RPMI 1640 medium with/without 10% fetal bovine serum, and then cells were replated on cell culture dishes coated with poly-HEMA in the presence or absence of serum. On the other hand, EGFR inhibitor, PI3K inhibitor, and EGCG were treated to the anoikis status cells, in order to evaluate the factors of anoikis. The result revealed that growth factors or loss of adhesion can increase phosphorylate Akt. In addition, lack of cell adhesion fails to activate pro-apoptotic factors directly. Activity of Erk kinase depends on not only EGFR signaling but also cell adhesion. Akt activation is mainly affected by EGCG whereas Raf-1 activation is controlled by the presence of cell contact. In addition, EGCG increased the level of NFkB, whereas phophroylated PTEN and total PTEN were not different. In this report,increase of NFkB was correlated with Akt phosphorylation, suggesting that EGCG can protect cells from detachment–induced cell death through Akt activation and subsequent NFkB

Disruption of cell - matrix attachment results in a loss of prosurvival signals and culminates in programmed cell death, referred to as anoikis , Apoptosis signal- regulating kinase 1(ASKl)/MKK5 is a ubiquitously expressed enzyme that acti vates c-Jun N-terminal kinase/stress-activated protein kinase JNK/SAPK and p38 pathways by direct site specific Ser/Thr phosphoryl ation of their respective MKKs-MKK4/MKK7 for JNK and MKK3/MKK6 for p38 kinases, The kinase activity of ASKl is stimulated by a variety of death signals, including TNF, Fas ligation, reactive oxygen species, and antineoplastic agents , The aim of this study was to investigate the relative importance of ASKl in anOlkls 1n the present study cells which lost their adhesion showed higher rate of cell death in compared to cells which maintained anchorage. 1nterestingly the res ult showed that suspended cells expressing ASK1 were more susceptible to anoikis than suspended cells having no ASK1 1n addition, cellu lar attachment seems to have significant effect on ASKl activity and p38 MAPK protein rather than serum stimulation