Thread: Tumor cells

So tumors start out as a clump of cells that divide and get bigger and metastasize. Does this mean they can grow on top of each other, bypassing contact inhibition? What is it that allows them to do grow on each other like that...as opposed to normal cells? Also, can tumor cells grow on on top of each other instead of a monolayer like normal cell in cell culture? Thanks.

Yes, transformed cells typically display anchorage-independence (as demonstrable with the use of soft agar assays) and loss of contact inhibition. To metastasise also requires the ability to invade into surrounding tissue by breaking down components of the extracellular matrix (ECM) and to enter blood vessels or the lymph system. Loss of contact inhibition can indeed be studied in vitro as in Kubota et al (1997) Fig. 1:

ci.jpg

Fig. 1.

Loss of contact inhibition by transfected 10T12 cells overexpressing ornithine decarboxylase (ODC). Representative G418resistant colonies derived from ODC-overproducing cells were grown to confluence and show loss of cell-to-cell contact inhibition by forming multilayered foci. A typical focus of ODC-3 is shown (original magnification ×200).

I am struggling to find a decent, comprehensive review of the molecular basis of contact inhibition, I will try again in the morning after sleep, in the meantime here is a review that focuses on the role of nectins in contact inhibition: http://www.nature.com/nrm/journal/v9...l/nrm2457.html Takai et al (2008) Nectins and nectin-like molecules: roles in contact inhibition of cell movement and proliferation. Nature Reviews Molecular Cell Biology. (Let me know if you can't access the full text and I will send the PDF to you).


Ref.

Kubota et al (1997) Ornithine Decarboxylase Overexpression in Mouse 10T12 Fibroblasts: Cellular Transformation and Invasion. JNCI Ornithine Decarboxylase Overexpression in Mouse 10T12 Fibroblasts: Cellular Transformation and Invasion

Seluanov et al (2009) Hypersensitivity to contact inhibition provides a clue to cancer resistance of naked mole-rat. PNAS

Hypersensitivity to contact inhibition provides a clue to cancer resistance of naked mole-ratest wishes,

Tridimity

It depends on the type of tumor actually.. Most cancerous cells multiply unchecked, but there are also those who restrict themselves in growth, eiter on creating filaments, of by creating a thin layer of cells.

Though at trimidity.. Contact inhibition? i'm not sure what you mean by that..

Though at trimidity.. Contact inhibition? i'm not sure what you mean by that..

Hi Zwolver,

Normal cells do not undergo mitosis when in contact. One hallmark of transformed cells is that they lack such contact inhibition. This is perhaps most easily observable in vitro - cells in which contact inhibition mechanisms are still in place will typically form a confluent monolayer and proliferation will stop; cells lacking contact inhibition will continue to proliferate even after having formed a confluent monolayer.

http://en.wikipedia.org/wiki/Contact_inhibition

Best wishes,

Tridimity