Anoikis

Anoikis is a form of apoptosis which is induced by anchorage-dependent cells detaching from the surrounding extracellular matrix (ECM)cite journal | author=Frisch SM, Screaton RA| title=Anoikis mechanisms| journal=Current Opinion in Cell Biology| year=2001| volume=13| issue=5| url=http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Retrieve&list_uids=11544023| pages=555–562| doi=10.1016/S0955-0674(00)00251-9] . Usually cells stay close to the tissue to which they belong since the communication between proximal cells as well as between cells and ECM provide essential signals for growth or survival. When cells are detached from the ECM, "i.e." there is a loss of normal cell-matrix interactions, they may undergo anoikis. However, metastatic tumor cells may escape from anoikis and invade other organs.

The word Anoikis was coined by Frisch and Francis in a paper published in the Journal of Cell Biology in 1994. Anoikis, in their words, means "(...the state of being without a home) to describe the cells' apoptotic response to the absence of cell-matrix interactions."

Anoikis in metastasis

The mechanism by which invading tumor cells survive the anoikis process remains largely unknown. Recent findings suggest that the protein TrkB, best known for its role in the nervous system, might be involved together with its ligand, brain-derived neurotrophic factor (BDNF). It seems that TrkB could make tumor cells resistant to anoikis by activating phosphatidylinositol 3-kinase (PI3K) signaling cascade.In squamous cell carcinoma, researchers have found that anoikis resistance can be induced through hepatocyte growth factor (HGF) activating BOTH extracellular signalling-receptor kinase (ERK) and PI3K.

ee also

*Metastasis
*apoptosis

References

SM Frisch and H Francis, J Cell Biol. 1994 Feb;124(4):619-26.Disruption of epithelial cell-matrix interactions induces apoptosis.

* Lance A. Liotta and Elise Kohn. (2004) Cancer and the homeless cell. "Nature". 430:973-974. [http://www.nature.com/nature/journal/v430/n7003/abs/430973a.html [abstract] "free" [http://www.nature.com/nature/journal/v430/n7003/full/430973a.html [fulltext] "subscription req"
* Zeng, Q., Chen, S., You, Z., Yang, F., Carey, T.E., Saims, D., and Wang, C.-Y. (2002) Hepatocyte growth factor inhibits anoikis in head and neck squamous cell carcinoma cells by activation of ERK and Akt signaling Independent of NFkB. Journal of Biological Chemistry. 277(28):25203-25208 [http://www.jbc.org/cgi/content/full/277/28/25203 [fulltext] "free"