Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.
Cancer fighting virus approved for melanoma
(Disclaimer: While this isn’t a story about stem cells, it’s pretty cool so I had to include it.)
The term “virus” generally carries a negative connotation, but in some cases, viruses can be the good guys. This was the case on Tuesday when our drug approval agency, the US Food and Drug Administration (FDA), approved the use of a cancer fighting virus for the treatment of advanced stage melanoma (skin cancer).
The virus, called T-VEC, is a modified version of the herpesvirus, which causes a number of diseases and symptoms including painful blisters and sores in the mouth. Scientists engineered this virus to specifically infect cancer cells and not healthy cells. Once inside cancer cells, T-VEC does what a virus normally does and wreaks havoc by attacking and killing the tumor.
The beauty of this T-VEC is that in the process of killing cancer cells, it causes the release of a factor called GM-CSF from the cancer cells. This factor signals the human immune system that other cancer cells are nearby and they should be attacked and killed by the soldiers of the immune system known as T-cells. The reason why cancers are so deadly is because they can trick the immune system into not recognizing them as bad guys. T-VEC rips off their usual disguise and makes them vulnerable again to attack.
This is exciting news for cancer patients and was covered in many news outlets. Nature News wrote a great article, which included the history of how we came to use viruses as tools to attack cancer. The piece also discussed options for improving current T-VEC therapy. Currently, the virus is injected directly into the cancer tumor, but scientists hope that one day, it could be delivered intravenously, or through the bloodstream, so that it can kill hard to reach tumors or ones that have spread to other parts of the body. The article suggested combining T-VEC with other cancer immunotherapies (therapies that help the immune system recognize cancer cells) or delivering a personalized “menu” of cancer-killing viruses to treat patients with different types of cancers.
As a side note, CIRM is also interested in fighting advanced stage melanoma and recently awarded $17.7 million to Caladrius Biosciences to conduct a Phase 3 clinical trial with their melanoma killing vaccine. For more, check out our recent blog.
Lab-grown guts work in mice and dogs
If you ask what’s trending right now in stem cell research, one of the topics that surely would pop up is 3D organoids. Also known as “mini-organs”, organoids are tiny models of human organs generated from human stem cells in a dish. To make them, scientists have developed detailed protocols that sometimes involve the use of biological scaffolds (structures on which cells can attach and grow).
A study published in Regenerative Medicine and picked up by Science described the generation of “lab-grown gut” organoids using intestine-shaped scaffolds. Scientists from Johns Hopkins figured out how to grow intestinal lining that had the correct anatomy and functioned properly when transplanted into mice and dogs. Previous studies in this area used flat scaffolds or dishes to grow gut organoids, which weren’t able to form proper functional gut lining.
What was their secret recipe? The scientists took stem cells from the intestines of human infants or mice and poured a sticky solution of them onto a scaffold made of suture-like material. The stem cells then grew into healthy gut tissue over the next few weeks and formed tube structures that were similar to real intestines.
They tested whether their mini-guts worked by transplanting them into mice and dogs. To their excitement, the human and mouse lab-grown guts were well tolerated and worked properly in mice, and in dogs that had a portion of their intestine removed. Even more exciting was an observation made by senior author David Hackham:
“The scaffold was well tolerated and promoted healing by recruiting stem cells. [The dogs] had a perfectly normal lining after 8 weeks.”
The obvious question about this study is whether these lab-grown guts will one day help humans with debilitating intestinal diseases like Crohn’s and IBS (inflammatory bowel disorder). Hackam said that while they are still a long way from taking their technology to the clinic, “in the future, scaffolds could be custom-designed for individual human patients to replace a portion of an intestine or the entire organ.”
Clinical trial using umbilical cord stem cells to treat HIV
This week, the first clinical trial using human umbilical cord stem cells to treat HIV patients was announced in Spain. The motivation of this trial is the previous success of the Berlin Patient, Timothy Brown.
The Berlin patient can be described as the holy grail of HIV research. He is an American man who suffered from leukemia, a type of blood cancer, but was also HIV-positive. When his doctor in Berlin treated his leukemia with a stem cell transplant from a bone-marrow donor, he chose a special donor whose stem cells had an inherited mutation in their DNA that made them resistant to infection by the HIV virus. Surprisingly, after the procedure, Timothy was cured of both his cancer AND his HIV infection.
The National Organization of Transplants (ONT) in Spain references this discovery as its impetus to conduct a stem cell clinical trial to treat patients with HIV and hopefully cure them of this deadly virus. The trial will use umbilical cord blood stem cells instead of bone-marrow stem cells from 157 blood donors that have the special HIV-resistance genetic mutation.
In coverage from Tech Times, the president of the Spanish Society of Hematology and Hemotherapy, Jose Moraleda, was quoted saying:
“This project can put us at the cutting edge of this field within the world of science. It will allow us to gain more knowledge about HIV and parallel offer us a potential option for curing a poorly diagnosed malignant hematological disease.”
The announcement for the clinical trial was made at the Haematology conference in Valencia, and ONT hopes to treat its first patient in December or January.