The creation of cancer cells is a process that researchers are still trying to fully understand.
Normally, normal cells grow and multiply, replacing old and damaged cells. Sometimes this process stops working, causing the cells to grow out of control and to develop until they become a tumor, as clarified in an article by the Conversation.
Traditionally, cancer treatments – chemotherapy, immunotherapy, radiation and surgery – have focused on killing cancer cells. Another type of treatment using stem cells, called differentiation therapy, focuses on transforming cancer cells into normal cells.
Stem cells are non-specialized cells, which means they can become any of the many types of cells that make up different parts of the body. They can replenish cells in the skin, bone, blood, and other organs and regenerate and repair damaged tissue.
There are different types of stem cells. Embryonic cells are the first to be formed, after a sperm fertilizes an egg, and can give rise to all other types of cells in the human body.
Adult stem cells are more mature, meaning they can replace damaged cells in only one type of organ and have limited ability to multiply. Researchers can reprogram adult stem cells in the lab to act like embryonic stem cells.
Cells become specialized during development.
Stem cells can survive longer than normal cells, having a more likely to accumulate genetic mutations. That’s why many tumors contain a small population of stem cells. These are thought to be responsible, at least in part, for cancer initiation, progression, metastasis, recurrence, and resistance to treatment.
Analyzes also show that cancer stem cells can differentiate into multiple cell types, including non-cancerous cells. Researchers are taking advantage of this with a type of treatment called differentiation therapy.
The concept was created after scientists observed that hormones and cytokines – fundamental proteins in cell communication – can stimulate stem cells to mature and lose its ability to regenerate.
Forcing cancer stem cells to differentiate into more mature cells prevents them from multiplying, turning them into normal cells.
Differentiation therapy has been successful in treating acute promyelocytic leukemia, an aggressive type of blood cancer. In this case, retinoic acid and arsenic are used to block a protein that prevents myeloid cells (a type of cell derived from bone marrow) from maturing. By allowing these cells to mature, they lose their cancerous qualities.
Furthermore, because differentiation therapy does not focus on killing cancer cells and does not compromise healthy cells with harmful chemicals, it can be less toxic than traditional treatments.
There are many other ways to use stem cells to treat cancer. For example, cancer stem cells can be directly targeted to stop their growth, or turned into “Trojan horses” that attack other tumor cells.
Silent cancer stem cells, which do not divide but are still alive, are another potential target. These cells play a big role in resistance to treatment in many types of cancer because they are able to regenerate and avoid death even better than normal cancer stem cells.
These can last for decades.. They are also a challenge to distinguish from regular cancer stem cells, making them difficult to study.
Researchers can also genetically engineer stem cells to express a protein that binds to a desired target on a cancer cell, increasing the effectiveness of treatments by delivering drugs directly into the tumour.
For example, mesenchymal stem cells, derived from the bone marrow, naturally migrate towards and adhere to tumors and can be used to provide drugs directly into cancer cells.
While stem cells have numerous advantages in their use in cancer therapy, they also face a number of challenges. Many current stem cell therapies that are not used in combination with other drugs are unable to completely eliminate tumors.
There are also concerns about stem cell therapies that can promote tumor growth.
Despite these challenges, stem cell technologies have the potential to open new avenues for cancer therapy. The integration of genetic engineering with stem cells can overcome the main drawbacks of chemotherapysuch as toxicity to healthy cells.
