For the People
The mandate of public biobanks is to provide access to a variety of different lines grown and maintained under strict quality control standards. They can act as an intermediary between researchers who might otherwise be asked to provide tissues and cells directly to their collaborators—shouldering the responsibilities of preservation, data collection, privacy, regulatory, and IP issues.
“First, we obviously want to preserve pristine, early passage stocks against any potential future accidents where you might lose the cell lines or they might undergo permanent, irreversible changes,” pointed out Glyn Stacey, Ph.D., director of the UK Stem Cell Bank (UKSCB).
Biobanks are charged with guaranteeing the authenticity of reliable, well-characterized, uncontaminated cells that are not mixed up with other cell types or switched with other cell lines.
It’s important to provide a direct link between the stocks of cells preserved in a freezer and the growing body of data associated with them. Information provided in the form of feedback from researchers as well as from periodic literature reviews is added to the cell’s documentation.
It’s vital to have a complete history of cells destined for human application, Dr. Stacey continued, including the method by which they were derived and maintained, all the way back to informed consent, “so they can go forward for clinical application with confidence in low levels of risk.”
The UKSCB can carry out independent verification of the findings of other laboratories. Patent repositories—the UKSCB is one—have for decades maintained the stocks required to check the veracity of a patent that is dependent on a particular culture.
Accepted stem cell lines must fulfill a series of acceptance criteria that cover most of the common features found in cell culture testing. These include being free from mycoplasma, bacteria, and fungi, as well as tests for viability and morphological examinations. And they must be free from common viral pathogens.
In addition, cells are assayed for a series of differentiation markers—“not essential for depositing in the bank,” remarked Dr. Stacey, but it’s useful “to know that these cells that have been sent to us are typical human embryonic stem cells, and they’re not deficient in differentiation capacity.”
Dr. Stacey explained that storage is maintained at three different levels, “which is quite normal for a tissue-banking environment”: quarantine, for new material that comes in untested; in-process, for which a bank of cells has been produced but testing is still under way; and long-term, where the culture is judged to be pathogen-free.
Not only is it important for tissue banking to be tightly controlled, but obtaining tissue samples and their associated data should be highly standardized as well. You have to “make sure you collect tissues that are representative of what’s going on in the body, not what’s going on during the collection process,” said Hartmut Juhl, M.D., CEO of Indivumed.
Perhaps 1,000 omics papers have been published, but not a single one defines exactly the same group of markers, Dr. Juhl noted. This is because biobank tissue has a handling history. Tissues change with the environment: they’re affected by oxygen, temperature, and pH.
Patients are given a host of different treatments before and during surgery, and these can be reflected in excised tissue as well. As an example, he pointed to a case in which a sequela of atropine administration was mistaken for a tumor biomarker.
Indivumed focuses on understanding the heterogeneity of tumors, and the differences of how patients respond to treatments, to help guide therapy. To this end, they maintain a biobank with about 14,000 tumor samples—with about 2,000 new cases added per year—each collected under very exacting specifications.
The company goes into the operating room with its own trained staff to collect blood and tumor for fixed, fresh, and frozen tissue samples, allowing for no more than seven minutes cold ischemia time. Three hundred clinical data points per patient—including 112 different compounds that may be seen before processing—are documented.
The company also works on finding protein biomarkers: what and how much is expressed, what post-translational modifications it displays, and the like. In general, it’s not worth bothering if you don’t know the stability of the protein you’re looking at, Dr. Juhl said. Take mitogen-activated protein kinase, for example: “if the sample is older than 10 minutes, you measure rubbish.”
A second goal of Indivumed is to find a way to correct data that was obtained in less-than-optimal ways, Dr. Juhl noted. But, he admitted, “this is still far away.”