Using cells in tissue culture

The last blog about the HeLa cells made me think about a question that is asked all the time. If we have cells that can grow in culture and can be used to test all aspects of biomedical science, why do we need to test in animals and in humans? The short answer is that cell culture (or tissue culture) -- other terms for growing human or animal cells in plastic dishes in the lab -- is just one part of the whole puzzle. It is just one of the items in the toolbox. Ideas and theories about how cells work and how a drug may be beneficial to stop cancer growth or make a heart cell beat are hashed out in cultured cells. These cells provide the basis (proof of principle) that theories work. These are also a single population of cells that are tested. Just muscle cells that comprise part of the heart can be grown in isolation. It is easy to test how these cells grow and work, but it is isolated and no other neighboring cells are involved or communicating with our heart muscle cell when it’s in culture systems. So, while tissue culture helps ID how heart muscle cells work, it is not an entire heart organ and may behave differently.

Many things can be tested initially in culture to determine if the hypothesis is correct and cells work the way scientists think they do. Say a new drug is developed. This drug could be designed to attack a particular target, for instance a certain protein in the cell that is involved in cell proliferation. First, the drug will be tested in tissue culture cells to see if it is effective, to learn more about how it works and if there could be potential unintentional side effects. Our new drug can effectively attack its target and stop cell growth, but it could also attack other targets and cause other outcomes. After the drug is tested and appears to be effective, animal models are next. FDA approved drugs must be tested in animals in order to get approval to be tested or used in humans. Many things can change when a whole organism is being tested including if the drug is effective. So, tissue culture serves an important role in labs but it isn’t everything and can be very different from what happens when the drug is given to humans.