HeLa – GOLLYGEE!

HeLa cells, cancer cells originally isolated from Henerietta Lacks, are among the most widely used cell lines for scientific research

Cell lines are frequently used in cancer research studies. They are pretty easy to maintain and they grow fast. The cell lines give us insight into some of the cellular pathways involved in tumor biology. They are often used as early-stage screens for potential cancer therapeutics, even though scientists know that they do not exactly share the same biology as an actual tumor. Cancer cells grow rapidly and they generate many mutations in the process. In a few cycles, the cells that you have in culture are different genomically than the cells that you started with. But still, having some information on what cells maybe doing in a tumor is better than no information at all.

Now Derek Lowe calls attention to a new study in Nature, which points out a potential problem with these cell lines in culture. In this new paper, the researchers found that not only are cancer cells different from the tumor that they started from, but there can be many differences within a strains of any given cell line. When they observed 27 strains of the MCF7 breast cancer line, the discovered rapid genetic diversification. They then looked at 13 additional cell lines and saw similar results. The genetic differences changed activation of gene expression, cell morphology and cell proliferation.

Derek Lowe sums up what this means for compound screening in cancer cell lines:

At least 75% of the compounds that showed strong inhibition of one MCF7 line were totally inactive against others. That’s going to confound experiments big-time, and this paper is a loud warning for people to be aware of this problem and to do something about it.

HeLa cells viewed under a light microscope

Nature magazine reports that a German lab has sequenced the DNA of HeLa cells. Like cells from most tumors, there are multiple copies of many genes. Excerpt:

Previous work showed that HeLa cells, like many tumors, have bizarre, error-filled genomes, with one or more extra copies of many chromosomes. To get a closer look at these alterations, a team led by Lars Steinmetz, a geneticist at the EuropeanMolecular Biology Laboratory in Heidelberg, Germany, sequenced the popular ‘Kyoto’ version of the cell line and compared the sequence with that of a reference human genome. The team’s results are published in G3.

Steinmetz’s team confirmed that HeLa cells contain one extra version of most chromosomes, with up to five copies of some. Many genes were duplicated even more extensively, with four, five or six copies sometimes present, instead of the usual two. Furthermore, large segments of chromosome 11 and several other chromosomes were reshuffled like a deck of cards, drastically altering the arrangement of the genes.

Without the genome sequence of Lacks’ healthy cells or that of her original tumor, it is difficult to trace the origin of these alterations. Steinmetz points out that other cervical tumors have massive rearrangements on chromosome 11, so the changes in the HeLa cell may have contributed to Lacks’ tumor.

HeLa cells have been the subject of many biological studies as they are easy to culture and replicate very fast. The cells were originally isolated from an African American woman named Henrietta Lacks, and have been cultured for over 60 years. There is also a fascinating book about the origin of these cells called The Immortal Life of Henrietta Lacks.

GOLLYGEE!

Tag: HeLa

the problem with cancer cells

DNA from HeLa cells is sequenced