Ki-67 expression and cell proliferation

[Stuart Hindle]

Dear Forum,

I was wondering if anybody had experience of using Ki-67 expression in the lymph node as a possible alternative endpoint for the LLNA? I am interested in evaluating its possible application and wondered if any other members had any experience and could comment on its advantages or possible pitfalls.

With best wishes,

Stuart

[Grace Patlewicz]

Hi Stuart,

I personally have no experience in Ki-67 expression and cell proliferation as a possible alternative endpoint for the LLNA. However I am seeking some experts in this field that might be able to provide you with a perspective. So far I am drawing a blank..but I will continue trying on your behalf.

Kind regards

Grace

[Grace Patlewicz]

Hi Stuart,

I have been asking around - 5 independent experts in the field of sensitisation - but I am still drawing a blank. It does appear that there is no experience in using Ki-67 expression in the lymph node as a possible alternative endpoint for the LLNA.

Let's hope someone viewing this post will register an opinion if they know otherwise.


Kind regards

Grace

[Grace Patlewicz]

Dear Stuart,
 
I spoke too soon. I have had some feedback for the Ki-67 just in.

Grace
 
"Based on work at RIVM, NL, Ki-67 has been found to be a reliable all-round proliferation marker, and most of their genomics experiments show that it correlates well with cell proliferation. Their lymph node microarray data does not cover this gene, but RIVM have found it to be a good cell division marker in the thymus and spleen. Hence they would expect it to correlate well with cell proliferation in an LLNA though they have not tried this in practice.
As for practical detals: in the past they have often used Ki-67 antibodies for immunohistochemical staining, this protocol being no more difficult than for other antibodies. For a more quantitative gene expression measurement, commercial QPCR kits are available from e.g. Applied Biosystems".
 

[Ed Delacruz]

http://toxsci.oxfordjournals.org/cgi/content/abstract/kfn247v1

I am sure that you have already seen this abstract.

[Grace Patlewicz]

Thanks, I did see the abstract too. I had contacted one of the authors to solicit their opinion but am still awaiting a reply...

[Stuart Hindle]

Dear Grace and Ed,

Sorry for my late reply, August here in Italy is holiday time!

First of all may I say many thanks for all your help and efforts to provide me with some further info.
It seems to me an interesting marker that maybe has not received much attention as there are currently 3 other methods using non-radioactive endpoints under evaluation by the regulatory authorities. However, the advantage I see with Ki-67 over these 3 other methods is that it would be possible to develop truly in vitro assays using currently available technologies (such as the toxicogenomic approaches mentioned). My idea is to perform correlative studies using known irritants, sensitizers e.t.c. to see if using Ki-67 is reliable, first in an ex-vivo setting and then using an in vitro platform.

If anyone out there is interested in such a project I would certainly love to hear from you.

With best wishes,

Stuart

[Ed Delacruz]

I hope you had a wonderful vacation.  The summers just don't seem to last long enough.

This is an interesting endpoint to investigate.  We perform a non-radioactive LLNA using flow cytometry where we determine proliferation of lymph node cells using BrdU.  Enhanced protocols of this method also allow for further discrimination by examining pro-inflammatory mediators, which can help distinguish between a sensitizing irritant and an irritating sensitizer.

How cost effective would gene chip arrays be compared to traditional rLLNA studies?