We implanted specific tumor cells (10^7 cell)and after 3 days, I checked tumor (diameter : about 3 mm). However, from tumor injection to now, tumor size of all mouse was not changed . Is it possible to be senescent in mice? If so, How to experiment animal test of naturally regressed tumor or senescent xenograft in BALB/nu mouse?
I agree with both Leonardo and James about the procedures to follow with xenografts done in non-immunodeficient mice. If you look at some of our xenografts that we've done previously (http://altogenlabs.com/xenograft-models/) you'll see that the kind of mouse is often correlated with the growth curve of a given cell line. Tumor growth can regress from a variety of factors (an immune response being the likely suspect) so it is preferable to use completely immunodeficient mice with hormonal supplements to match the cell line.
Three days isn't enough time to come to a conclusion. Cell-lines and xenografts have their own unique growth patters. For example- in my hands, 3*10^6 BT474s in mammary fat pad take about four to six weeks to get to 5-8mm in diameter, where as T47Ds take a week longer than BT474s. However, the same cells implanted into brain (metastatic model) , we did not wait for the tumors to grow upto 5-8mm, we measured them after a week and experimental groups or vehicle or therapy were assigned. Most of the xenograft models have been previously established, look through papers where people have used your cell line and model in question.
Dear Charan,
Thanks for your opinion.
I have one wonder. I know a complete immunity is not removed in BALB/nu mouse. Is not it related ? I hope your opinion.
Regards,
Daiha Shin
Nude mice have high levels of NK cells. Thus, if you use them for xenografts you need to give 3 injections of anti-asialo GM-1 antibody and frequently low levels (300 Rads) whole body irradiation prior to injecting the tumor cells. Other ways to reduce NK cells can be used.
Note, not all tumors especially primary tumors will grow in immunodeficent mice. Injecting tumor cells with irradiated nurse cells or in collogen (methacel) can help them establish primary tumors. Injection of the orthrotopic site can also help.
Dear Daiha,
I completely agree with the suggestions by Dr. James E Talmadge. What I could add is that up to my knowledge and experience (just with SCID mice) senescent xenograft tumors are mainly due to not properly selected cells. Usually you must select a high-replicating colony with the lowest dwell time. You should perform t least 5-6 selection passages in order to evaluate and choose the fastest growing colony.
Just a question:
"Are your cells adherent growing or non-adherent?"
Because in my experience the adherent are more able to develop xenograft tumor both orthotopic and ectopic, respect to the non-adherent one.
Best.
I agree with both Leonardo and James about the procedures to follow with xenografts done in non-immunodeficient mice. If you look at some of our xenografts that we've done previously (http://altogenlabs.com/xenograft-models/) you'll see that the kind of mouse is often correlated with the growth curve of a given cell line. Tumor growth can regress from a variety of factors (an immune response being the likely suspect) so it is preferable to use completely immunodeficient mice with hormonal supplements to match the cell line.