Hello,
I am trying to grow xenograft tumors with cells mixed with matrigel. I see that at the injection site, the gel sets and forms a bump. How do I measure the tumor growth accounting for the gel bump, that is while I am measuring tumor growth how do I differentiate between matrigel and tumors? I use caliper measurements for tumor growth.
I agree with Roman about the volume of the injected mixture (100 microliters is a good starting point). Our xenografts (http://altogenlabs.com/xenograft-models/) are done with matrigel for the most part, and by the end of the study the growth curves are so clear that the initial volume of matrigel becomes insubstantial. As long as your growth curves have a relatively similar starting point, you'll have statistically significant results from an effective drug regimen.
Cells cultured on Matrigel demonstrate complex cellular behavior that is otherwise difficult to observe under laboratory conditions. As an option - to differentiate the growth of primary tumor from the rest, by measuring the amount of vasculature in a conventional unit of time
Hi
For how long do you let tumors growth? as I understand you only get a small bump, am I right? I think you should let those tumors growth more in order to measure a reliable tumor. It seems that the bumps you are measuring are just local inflammation from the site of injections rather than an established tumor.
It happens to me in several experiments. There are cell lines that just don’t engraft in a good way in the host, so I was having those bumps and I did the histology and H/E staining and I realize those bumps are not tumors but only inflammation and necrotic tissue. So my advice would be to try with different cell lines in your xenograft experiment until you get real measurable tumors and not only small bumps.
Best.
As Carlos indicated, depending on the kind of cancer cell line and the host immunocompromised status, the xenograft only grows much smaller than you previously expected. In that situation, as mentioned above, the measurement after fixation and HE staining would be accurate. However, you have to prepare enough number of xenograft models to measure the xenograft size in the time course. Right?
One should subcutaneously inject "minimal but practical" volume of matrigel/cell mixtures, such as e.g. 100 uL. If this mixture contains approximately 10 mil cells, their volume is about 30 uL, so only 70 uL would correspond to matrigel. At the injection site matrigel consolidates and partially degrades in vivo, so its remaining volume will eventually be even lower. Furthermore, tumor cells grow within matrigel plug and matrigel thus becomes a part of the tumor. As a result, the volume of matrigel can be a source of error for tumor volume measurement only in very early stages, when the volume of tumor is less than those injected < 70 uL of matrigel, but at these stages the precision of tumor volume measurement by caliper is highly questionable. If you start recording tumor volumes at 100 uL and above, the volume of injected matrigel would not be of much relevance. Also note that exponential tumor growth is usually at 100-800 uL so this is the range at which measurements are most meaningful.
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