When I scroll through medical research articles and science news, one topic continues to pop up: stem cells. Hence, I decided to learn more about stem cells and why they’re important to medical research… as described in this article!

First off… what is a stem cell?

“Stem” does not stand for “Science, Technology, Engineering & Math” in this case, nor is it referring to part of a plant. Wait… hold on to that bit, it’s actually relevant here! Just as a stem sprouts from the ground following the formation of the roots of a plant, serving as a foundation for the other parts of a plant to grow, stem cells serve as the foundation for the other cells in the body. (And cells are the “building blocks of life.” They compose tissues, organs, organ systems, and organisms). 

Stem cells are immature cells that are able to differentiate into other cells, such as blood cells, that eventually mature and function as needed. 

In Different Parts of the Body

Just to make the idea of stem cells a little more concrete, below are a couple of examples of stem cells in the body: 

A blood stem cell is capable of differentiating into the following, as displayed in the diagram:

Furthermore, intestinal stem cells help renew the intestinal epithelium, especially throughout adult life.  

Induced Pluripotent Stem Cells (iPSC)… The Best Part of this Post 🙂

First, pluripotent stem cells are cells that have the ability to undergo self-renewal and to give rise to all cells of the tissues of the body; however, pluripotent cells cannot develop or give rise to an entire organism (totipotent cells can do this, though… I know, there’s a ton of vocabulary). 

Now, induced pluripotent stem cells are derived from skin or blood cells that have been reprogrammed back into an embryonic-like pluripotent state. 

During embryonic development, a child is considered an embryo from fertilization to ten weeks after. A blastocyst, or a cluster of cells made by a fertilized egg, is the early stage of an embryo. Embryonic stem cells are found in the inner cell mass of the human blastocyst; these stem cells normally disappear after the 7th day of fertilization and the pluripotent stem cells begin to differentiate into three embryonic tissue layers, as displayed in the image below: 

The ectoderm gives rise to the skin and nervous system; the endoderm forms the gastrointestinal and respiratory tracts, endocrine glands, liver, and pancreas; the mesoderm forms the bone, cartilage, most of the circulatory system, muscles, connective tissue, and more. 

Currently, induced pluripotent stem cells are created through retroviral or lentiviral transduction of reprogramming factors. In retroviral transduction, retroviruses are introduced into the host cell and have the ability to transform their single stranded RNA (ribonucleic acid) into a double-stranded DNA molecule that stably integrates into the genome of the host cell. Retroviruses only infect cells that are in the mitosis phase – the phase characterized by rapid division. This differs from lentiviruses (used in lentiviral transduction) which can target both dividing and slowly dividing cells – making them especially popular. While these methods are successful in reprogramming cells into their pluripotent state, they can lead to some mutations increasing the risk of cancer development; thus future research is warranted. 

One in their “pluripotent state,” these cells are capable of differentiating into any type of human cell needed for therapeutic purposes. 

But what are these therapeutic purposes? In terms of basic research, iPSCs can be used in the in-vitro modeling of diseases, then helping scientists discover potential treatments for them. Specifically, the cancer-derived iPSC model is used for studying the mutation of cancer-related genes in order to understand the mechanisms underlying tumor formation in humans. 

Current Research!

 I’ve been interested to learn more about research involving iPSCs, so I began to look into some of the scientific literature. 

This review article looks into how iPSCs can be developed into different cancer immunotherapies. It pushes for the need to use iPSCs to develop allogeneic (or universal) cell therapies, as iPSCs have the unique ability to renew, divide, and be engineered. Research in this started in the early 2010s, and involved transducing (introducing foreign DNA into a cell via a viral vector) iPSCs with a CAR (chimeric antigen receptor) or transgenic TCR (T-cell receptor) gene. iPSCs can be converted into antigen-specific T cells with impressive on-targeting efficacies. The chimeric antigen receptor is a receptor created in laboratories; they have the ability to bind to proteins on the membranes of cancer cells. 

The chimeric antigen receptors are then added to T cells, allowing them to kill cancer cells that have that specific protein; currently, T cells are being grown in the lab, and are being studied in the treatment of different types of cancer (CAR-T cell therapy). The production of CAR-T cell therapy is extremely expensive, and the hope is that using iPSCs can provide a more cost-effective solution. However, CAR-T therapy still has various side effects associated with it, and further research in this area is warranted. 

Currently, most research pertaining to iPSCs has to do with moedling diseases. However, there’s currently questions and research going on to determine whether iPSCs can be directly involved in treating diseases, specifically cancer, genetic disorders, and neurological disorders – and there is definitely great potential for this in the future. 

Thanks for reading! I hope this inspired you to become a little more fascinated with biology and develop questions in that area as well as in the field of stem cells. Please continue researching and learning more about this area if it interests you! Feel free to comment your thoughts, questions, ideas, knowledge, etc below! 

Sources: 

“Induced Pluripotent Stem Cells (iPS).” UCLA Broad Stem Cell Center, stemcell.ucla.edu/induced-pluripotent-stem-cells.

Kumar, Dharmendra, et al. “Induced Pluripotent Stem Cells: Mechanisms, Achievements and Perspectives in Farm Animals.” World Journal of Stem Cells, vol. 7, no. 2, Baishideng Publishing Group, Jan. 2015, p. 315. https://doi.org/10.4252/wjsc.v7.i2.315.

Molnar, Charles. “13.2 Development and Organogenesis.” Pressbooks, 14 May 2015, opentextbc.ca/biology/chapter/13-2-development-and-organogenesis.

Munis, Altar M. “Gene Therapy Applications of Non-Human Lentiviral Vectors.” Viruses, vol. 12, no. 10, MDPI, Sept. 2020, p. 1106. https://doi.org/10.3390/v12101106.

Pan, Xiu-Yang. “Application of Cancer Cell Reprogramming Technology to Human Cancer Research.” Anticancer Research, 1 July 2017, ar.iiarjournals.org/content/37/7/3367#:~:text=Potential%20Application%20in%20Biomedical%20Research&text=The%20cancer%2Dderived%20iPSC%20model,mechanisms%20underlying%20tumorigenesis%20in%20humans.

What Are Stem Cells –  Health Encyclopedia – University of Rochester Medical Center. www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=160&contentid=38#:~:text=Every%20type%20of%20blood%20cell,such%20as%20bone%20marrow%20transplants.

Zhou, Yang, et al. “Engineering Induced Pluripotent Stem Cells for Cancer Immunotherapy.” Cancers, vol. 14, no. 9, MDPI, May 2022, p. 2266. https://doi.org/10.3390/cancers14092266.