It’s exciting times if you’re an induced pluripotent stem cell (also called an iPSC). OK, so maybe these stem cells don’t actually feel excitement, but there’s still some amazing progress being made with iPSCs. This includes making functional livers out of them, modifying them to attack cancerous tumors, and using them in their first clinical trials.
But maybe we should take a step back first – what exactly are these cells and why should you care about them? Induced pluripotent stem cells are stem cells that have the ability to, theoretically, turn into any cell type of the adult body. In this way, they’re like human embryonic stem cells (called hESCs for short). Because of this ability, both of these cell types have great potential for making lab-grown tissues and organs needed in transplants.
But, unlike hESCs, the iPSCs can possibly be made out of any cells from a person’s body – ones that may not be missed much, such as from blood or fat tissue samples. (hESCs can only be made from early-stage embryos, called blastocysts.) How does this work? By forcing “normal” adult cells to make certain proteins that are essential for the hESC identity, those adult cells can turn into iPSCs. This means that not only is it easier to get cells to make iPSCs, but iPSCs can also potentially be patient-specific, bypassing immune rejection problems that often arise with transplants. Making iPSCs using human cells was demonstrated for the first time in 2007, and the research community has made amazing progress since then.
In just the last few months, there have been several impressive breakthroughs made using iPSCs – read on for the details:
- Two months ago, on June 2, 2013, a study was published in Nature Biotechnology showing that scientists could make iPSCs that attacked cancerous tumors. The researchers did this by genetically modifying iPSCs to become cells of the immune system (T cells) that were programmed to target cancer cells (specifically malignant B cells). They showed that these modified T cells could inhibit the growth of a cancerous lymphoma tumor in mice. Overall, it’s a very promising novel strategy for fighting cancer.
- Just last month, on July 3, 2013, a paper in Nature was published showing that iPSCs were successfully turned into what appeared to be functional liver buds. This is the first report showing that iPSCs can be used to make a functional human organ. It’s an amazing step forward to the goal of making lab-grown organs for the many people who desperately need transplants.
- Also last month, on July 18, 2013, researchers at Salt Institute for Biological Studies reported finding a more feasible way of making iPSCs. Previously, genes were usually randomly inserted into cells to make them become iPSCs, which could be dangerous if the new genes ended up disrupting important genes already in the cells. But the Salk group found a way to use a mixture of chemicals (called small molecules) instead of genes to make iPSCs, which should make it safer to use iPSCs in transplants.
- Around that same time, the Japanese government approved the first clinical trial using iPSCs. This was specifically to use retinal cells (derived from iPSCs) to treat people with age-related macular degeneration (AMD), a common cause of blindness in older people. If all goes well, this could just be the first of many iPSC clinical trials for various medical treatments.
iPSCs are definitely going places, and getting there fast! With continued support and funding, these cells will likely show up in many useful treatments in the near future.
For further reading:
- Teisha J. Rowland’s book Biology Bytes: Digestible Essays on Stem Cells and Modern Medicine
- Teisha J. Rowland’s blog posts at All Things Stem Cell: “Induced Pluripotent Stem Cells: A New Stem Cell Line with a Long History,” “Human Embryonic Stem Cells: A Decade of Discovery, Controversy, and Potential,” and “Visual Stem Cell Glossary.”
- Maria Themeli et al.’s article “Generation of tumor-targeted human T lymphocytes from induced pluripotent stem cells for cancer therapy” in Nature Biotechnology
- Chris Palmer’s articles “Tumor-Targeting T Cells Engineered,” “Livers Created from Stem Cells,” and “Chemical Reprogramming of Stem Cells” in The Scientist
- Takanori Takebe et al.’s article “Vascularized and functional human liver from an iPSC-derived organ bud transplant” in Nature
- Salt News Release’s article “Salt scientists discover more versatile approach to creating stem cells”
- Bob Grant’s article “First Ever iPS-Cell Trial a Go” in The Scientist