Tools of the Trade

Like all disciplines, cancer research has specific tools and techniques that are routinely used by all practitioners. We will discuss many of the most common but the field is changing very quickly so everything can't be included.

Cell Lines

Use of animal cell lines for research became routine in the 1950s. Cells were isolated from their source tissue and immortalized (kept alive) so that they continued to reproduce identical cells that could be studied at different times and in many different laboratories.

The use of human cell lines in research has raised some ethical issues. These cell lines can outlive the person who donated them, and lead to discovery of medical treatments that are profitable for the drug companies that manufacture the drugs, but not for those who donated the original cells that were used for their development. In the pioneering decision in this area, the Supreme Court of California held in Moore v. Regents of the University of California that human patients have no property rights over cell lines derived from organs removed with their consent.

The NCI and other labs maintain a large number of standard animal and human cancer cell lines, each of which have been studied in considerable detail.

Frequently used cell lines:

MCF-7: Breast cancer T47 D: Breast cancer DU145: Prostate cancer PC3: Prostate cancer THP-1: Acute myeloid leukemia U87: Glioblastoma Saos-2: Bone cancer

When evaluating research conducted using cell lines it is useful to ask a number of questions:

• Human or animal cells? Human cells are preferable since they are more similar to actual cancer in patients
• Cancer or normal cells? May want both but need to know which
• How many lines? The more the better
• Why were these lines chosen? Reasons should be given
  • Advantages
  • Disadvantages
  • Alternatives considered

Cell Cultures

The type of culture in which cell lines are grown and studied is also important to consider. It is simplest and least expensive to grow cells in a 2-D petri dish containing a nutritious medium like agar.

Regardless of the details of the model, the basic conceptual approach of molecular biologists is relatively simple. Scientists control all but a single variable at a time and explore the molecular consequences of simple changes.

For example, a set of petri dishes can be randomly divided into two groups with one of the groups exposed to a specific chemical or radiation. Then the differences between the two groups are examined.

The progress of any differences over time may be also carefully explored. While this paradigm is conceptually simple, the types of manipulation can be exceeding sophisticated (e.g., adding a methyl group to a specific gene at a particular moment in the cell cycle), as well as the types of differences among the groups that are measured (e.g., the likelihood of a specific mutation in future generations of cells).

Techniques to conduct these manipulations and to provide very sophisticated molecular analyses of the results are rapidly evolving, making discoveries possible today that were not possible just a decade ago.

CISN Summary

• Cell lines and cell cultures are two tools that are often used in research.
• Basic research is very important because it lays the foundation for other types of research to follow.