Hi,
The aim of my study is to investigate the effect of the gene of interest on metastasis. I chose to experimental metastasis and have injected tumor cells (100,000 PY8119 or B16 cells) into the lateral tail vein of B6 mice (6 to 10 weeks). The success of tail vein injection was verified by "no resistance while injecting" or "bleeding after the injection". Also, I convinced around 90% of clean shots without failure.
In 2 and 3 weeks, some mice showed paralysis of hind legs or the presence of mass under the skin. As time goes by, many mice were found to have "ectopic tumor generation" in their skin, abdominal cavity, peritoneal cavity, and ocular area. However, they also had metastasis in their lung and liver. I expected that the tumor mass should appear only in blood-related organs, such as the liver and lung. This has a problem in the mouse death cannot be explained by the lung metastasis.
Did I make a mistake during tail vein injection? Can you explain this phenomenon?
Thank you.
Where is the primary organ for this cáncer cells, where should be homing? Are a breast cancer cell line really? So not shoud really engraft in bone marrow or in some specific hematologic organ, right?. If You inject by IV they have the potential to go to any tissue and if not preferentially engraft in one, You are going to observé a plethora of tumor phenotypes. Not an expert in metástasis studies, but have sense drop solid tumor cells in blood to study metástasis? Why not reproduce solid tumor phenotype (e.g. breast cancer phenotype) with your gene modified cells/mice and see if increase tissues with metástasis?
Sorry for the delayed response.
Here is my answer for you.
1) Where is the primary organ for this cáncer cells, where should be homing?
-> PY8119 and B16 cells were derived from breast cancer and skin melanoma. They are reported to home to the lung after IV injection.
2) Are a breast cancer cell line really? So not shoud really engraft in bone marrow or in some specific hematologic organ, right?
-> PY8119 cells are breast cancer cell line. Yes. Exactly, I injected tumor cells into vein.
3) If You inject by IV they have the potential to go to any tissue and if not preferentially engraft in one, You are going to observé a plethora of tumor phenotypes.
-> It's surprise. But, it could be possible. do you have any reference of this?
4) Not an expert in metástasis studies, but have sense drop solid tumor cells in blood to study metástasis? Why not reproduce solid tumor phenotype (e.g. breast cancer phenotype) with your gene modified cells/mice and see if increase tissues with metástasis?
-> When I performed study of spontaneous metastasis, there cells grew really fast and didn't go to the lung effectively, so I changed the strategy to use experimental metastasis, which is tail vein injection.
Thank you so much.
Just an additional question, the cells have tropism for the lung or only keep trapped in the microvessels of the lung? As I said, i work with hematological cells so I not have this problem because is a clear tropism for bone marrow and/or spleen, but I believe is common multiple cell lines are trapped and kidnapped by the lung, not necessarily being a preferentially engraft tissue.
Anyway, as you use a genetically modified cell line, why you not modified your cells with a reporter such as LUC in the cell line and use IVIS monitoring? Probably is going to be easy for you to reveal where is the primary engraft niche (if is a specific preferential niche, such as lung as is described), and see if causes dissemination and metastasis from that primary niche, because, for instance, you mention lung metastasis, but, in fact, you don't know if primary tumor as generated in lung, and cause metastasis in other areas, right?
Good luck
Best,
Miguel.