While the TUBO cell line was derived in BALBc mice, it sounds like you possibly had an immunorejection of the tumor. Have you attempted growing this cell line in an immunocompromised mouse to see if you get the same effect? This would help you rule out this hypothesis.

Another potential hypothesis would be that the tumor is not becoming vascularized. Initially, the tumor could expand based on nutrients provided in the interstitial fluid of the subcutaneous tissue, but as the tumor expands its size exceeds the amount of oxygen and nutrients it can obtain without proper vascularization. In this event, the tumor may become necrotic, and thus reabsorbed.

Have you sacrificed a mouse at any time points once the tumor has started regressing to take a look at the macro and microscopic changes in the cells? This could give you a clue as to what is going on, as opposed to just examining the external mass of the tumor.

Last, if you use TUBO cells that are luciferized, you can not only get a relative mass of the tumor but also a rough estimate of viability (as luciferase light generation will only occur in live cells due to its need for ATP). This could also be helpful if you see a lack of luciferase light generation at certain time points, thus you will know the cells are dead or dying.

Good luck,

~Adam

Try to implant into the neuT transgenics; Balb/c (without the transgene) can generate a T cell response to the neu antigen thus rejecting tumors.

Thank you

Santos is right, I have seen that as well. In neuT mice TUBO cells grow just fine. However, depending on whether you have the activated neuT mice, females develop fast growing autochtonous tumors very quickly (by 4months, males about 8 months). This will interfere with your experiments. You might also try to inject the TUBO cells into the mammary fat pad, this othologous implantation may improve the take rate...

can anyone tell me where to obtain BALB-neuT mice and TUBO cell line?