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Tumor Xenograft model - (Sep/10/2013 )

Hi all,

 

I recently induced tumors in a xenograft model MDA-MB-468 using Athymic nude mice in the dual flanks.

 

I used BD matrigel basement membrane matrix at high concentration.

 

The cells were at a concentration of 4x10^6 with the matrigel.

 

The volume I used was about 200uL of the cells to total the 4million, combined with 200uL of the matrigel.

 

The suspension was very gel like, and everything was kept on ice, and syringes were loaded prior to inoculation.

 

I injected the cells subcutaneously on the mice, with the 400uL suspension.

 

What was observed the first day was a gel like aqueous suspension in the SC layer of the mice, some of it came out.

 

I have observed the mice daily since the injection, while the size has shrunk a bit, the size is still quite a decent size.

 

I am not sure if this is a tumor? Actually I anesthetized the mice to check the feel , and it seems to be a hard solid lump after 7 days.

 

The sizes range from around 100-150mm^3. 

 

Could the tumor actually form this quick, should we wait another week or two to begin treatment? If not, what do you suspect happened?

 

Thanks so much

 

-shamash119-

All your procedures seem OK to me except the volume which is too big, resulting in leaking. 100 ul cells + 100 up matrigel should be good. The bumps you initially saw are mostly matrigel and may go away. That is fine. Tumors typically appear 3~4 weeks after cell inoculation depending on the number of cells used.

 

Some tips to increase success rate:

 

  • Change fresh medium 3 hours before harvesting cells
  • Minimize typsin digestion time
  • Minimize centrifugation force and time
  • Make sure injection is subcutaneous, not intradermal, not inject into muscle
  • Advance needle for a short distance after entering subcutaneous space so that the injected cells won't come out easily.
  • Apply gentle pressure to the hole in the skin using fingers after needle withdrawal. 

-pcrman-

Thanks for the reply, I guess it has only been 8 days since the implantation. But the funny thing is that there is still some good size lumps on almost 100% of all the mice that are present on both of the flanks which when measured with the calipher are all about 100-150mm^3 in volume.

 

Is that typically normal to see? Basically the size of the lump has gone down a little since day 0 but has remained quite a decent size since the day of the injection. 

 

Thanks again so much for the help.

-shamash119-

The lumps could be the inoculated cell mass and may start to grow in a while. Based on my experience, there are two types of xenograft tumors: one are those grown from small number of starting cells, take 2-4 weeks to appear, and are usually firm in consistency. The other are derived from injecting too many cells, appear from the start of injection, are soft in consistency, and are consist of mainly tumor cells without much infiltrating connective tissue from mice.  

-pcrman-

Hi, how many cells would you inject in the 100uL + 100uL of matrigel? I have also found that with such a low volume some of the solution does stay in the syringe after injection.

-shamash119-

Depending on cell types, 3-5 x 10^6 cells are usually injected. 

-pcrman-

Hi, I wanted to ask you, i did inject the cells 2x10^6 100uL + 100uL of matrigel into the flanks of the mice, the next day there is actually nothing much visible, do you know how long it takes to grow the tumors? should there be a bump evident?

-shamash119-