FBS contains many very potent cell signaling factors like TGF-B, Retinoic Acid, Estrogen, and Testosterone that obscure our ability to detect and understand metabolic pathways that lead to cancer. Below are a few points to consider concerning the in vivo environment that cancer cells live in and that FBS exposure doesn’t mimic those environments. Using a chemically defined serum replacement like Cell-Ess will enable your cancer cells to behave in a way they do not when exposed to the abnormal cocktail of signaling factors present in FBS.
- In solid tumors there is tight regulation between extravasation of cells and movement of molecules from the blood vessel into the solid tumor. All of this is bypassed by culturing in a blood product.
- There is a sensitivity around the metabolic pathways, one of which is governed by PD-1 and PDL-1. There is metabolic sensitivity to cholesterol and fat levels. For those culturing in serum do not have control over the metabolic agents. And those culturing in typical serum-free media products do not have any fats or cholesterol.
- There is a critical importance to tumor microenvironment. Using a blood product like serum mimics a macro-environment of blood.
- Aromatase is a rate-limiting step in breast cancer. Aromatase makes estrogen. Estrogen is made from cholesterol. In typical serum free media products, there is no cholesterol and no estrogen therefore model for breast cancer. The presence or absence of cholesterol is also important along with knowing the other hormones, so working with serum is also a terrible choice.
- TGF-b alone has a potent effect on cancer and is in serum.
- IGF-1 overexpression can result in insulin resistance seen in progressive cancers. And there is an overabundance of IGF-1 in FBS.
- Cancer progression is driven by the need for angiogenesis (the de novo growth of blood vessels). Using FBS may change the signals tumors allocate for initiating the angiogenic pathway.