Shared from the 3/11/2019 Chemical & Engineering News eEdition

CANCER

Cancer cell-line ancestry misassigned

‘African American’ prostate cancer cell-line carries greater than 90% European ancestry

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Micrograph of the misclassified E006AA-hT cell line

Cell lines are one of cancer researchers’ most powerful tools for studying the disease. These cells allow scientists to probe cancer’s molecular mechanisms: how it starts and spreads and what molecules fuel or suppress it. Biologists create these cell lines by searching through donated cancer cells from individual patients to find cells that can be immortalized, meaning they can be grown again and again in petri dishes and in mice.

While the most famous cell line, HeLa, came from an African American patient, Henrietta Lacks, the majority of cancer cell lines are derived from patients with European ancestry. Yet researchers have increasingly observed differences in how certain cancers behave at the biological level in various ethnic groups, highlighting the need for ethnically diverse cell lines to probe the molecular basis for these differences.

In the past, scientists assigned an ethnicity to a cell line through a doctor’s observation or a self-report by the patient. Now, a multi-institutional team of researchers has analyzed the genetic ancestry of 15 prostate, breast, and cervical cancer cell lines and found that several lines labeled as mixed or black/African American had been misclassified (Cancer Epidemiol., Biomarkers Prev. 2019, DOI:10.1158/1055-9965.EPI-18-1132 ). The authors say the results should motivate scientists to confirm the identity of cell lines they use in experiments.

The team, led by Rick A. Kittles at the City of Hope and K. Sean Kimbro of North Carolina Central University, used a set of 105 ancestry genetic biomarkersspecific DNA base differences commonly found in people of a certain ancestry—to determine the percentage of each cell line’s West African, Native American, and European ancestry. The team reports that HeLa cells contain 66% West African ancestry, which is slightly lower than the average of about 80% West African ancestry for US born African Americans. The scientists also found that one prostate cancer cell line called 22Rv1 had 99% European ancestry though it had previously been determined to have mixed ancestry using a small panel of biomarkers. (Prostate 2017, DOI:10.1002/pros.23437 )

The main misclassification was in a prostate cancer cell line called E006AA-hT, which is labeled and sold by vendors as African American but actually carries 91% European ancestry.

Prostate cancer disproportionately affects black men, whose mortality rate from the disease is twice that of the rate for white men, according to the Centersfor Disease Control and Prevention . Also, prostate cancer tends to be associated with more inflammation and to be more aggressive in African American men than in men of European ancestry, suggesting a biological difference. Yet only two of the dozen most common commercially available prostate cell lines are sold as African American; the rest are sold as having European ancestry.

Several cancer researchers told C&EN that they will stop using E006AA-hT as an African American cell line. But some point out that the cells could still be useful as a general prostate cancer cell line.

Nishadi Rajapakse, a biologist and program director at the National Institute on Minority Health and Health Disparities, says that as part of the agency’s mission to reduce health disparities, it has funded efforts to improve diversity and representation of underrepresented groups in biomedical research. Studies like this one are important, she says, because they encourage researchers to verify their cell lines’ ancestry.—TIEN NGUYEN

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