Surgical intervention and chemotherapy do not always provide the successful result to treat metastatic cancer and reoccurrence becomes a common incidence of treatment failure. Stem cell therapy is a relatively new therapeutic approach to treat cancer and shows promising results in cancer treatment. Depending upon the source of stem cells, the proliferation, migration, and differentiation capacity also alters, and that determines the anti-tumor application of specific stem cell treatment.
Depending upon the ability of stem cells, the definition can vary. For example, some stem cells are indefinitely self-renewable, some have the ability to generate single cell-derived clonal cell populations, or can differentiate into various cell types.
Pluripotent stem cells (PSCs) and Embryonic stem cells (ESCs) are used in anticancer vaccine production. These stem cells initiate effector T and NK cells. However, the sources of PSCs and ESCs are different. PSCs are derived from somatic cell culture, whereas ESCs generates from the undifferentiated inner mass cells of the embryo. ESCs have the great ability to generates all types of cells, except placental cell development. But Embryonic Stem Cells application in a clinical trial is unethical.
Neural stem cells (NSCs), hematopoietic stem cells (HSCs), and mesenchymal stem cells (MSCs) are different types of Adult Stem Cells (ASCs) that are commonly used in cancer treatment.
NSCs are self-renewable cells present CNS (central nervous system). The preclinical trial report stated that NSCs had efficacy in treating both early staged and metastatic staged breast, prostate, and lung cancers.
HSCs are originated in the bone marrow and have the ability to generates all types of mature blood cells in the body. FDA has only approved the infusion of HSCs derived from cord blood to treat leukemia, multiple myeloma, and some kinds of blood system disorders.
MSCs are located in different tissues and organs. MSCs play an important role in tissue repair and regeneration. In- vitro study results reported that MSCs can generate and proliferate adipocytes, chondrocytes, and osteocytes. The unique biological properties of MSCs can treat a variety of cancers.
Cancer Stem Cells (CSCs) are tumor-initiating cells that are found in tumor tissues. These Stem cells are taking part in cancer growth, spreading, and recurrence. Therefore, targeting CSCs can help to treat different types of solid tumors.
NSCs and MSCs are the most common Stem cells which can be modified via different mechanisms for possible use in cancer therapies. The therapeutic enzyme/prodrug system and nanoparticle or oncolytic virus delivery at the tumor site are certain common mechanisms of Stem cell modification.
Stem cells applications in cancer therapy
| Strategies | Cancer types | Stem cell applications |
| Stem cell modifications | ||
| Enzyme/prodrug therapy | Glioma | NSCs (retroviral transduction with CD) |
| NSCs (baculoviral transduction with HSV-TK) | ||
| MSCs (lentiviral and retroviral transduction with S-TRAIL and HSV-TK) | ||
| MSCs (retroviral transduction with CD ) | ||
| Colon adenocarcinoma | NSCs (adenovirus transduction with a rabbit CE) | |
| Metastatic lung cancer and primary lung cancer | NSCs (engineered to express CE) | |
| Secreted agents | Glioma | NSCs (retrovirus transduction with IL-4 ) |
| NSCs (adenovirus transduction with TRAIL) | ||
| NSCs (encapsulated in sECM after being engineered to express S-TRAIL) | ||
| Breast cancer brain metastases | NSCs (lentivirus transduction with anti-HER2Ab) | |
| Breast cancer | MSCs (engineered to overexpress IFN-beta) | |
| Viral therapy | Glioma | NSCs (infected with CRAd-S-pk7) |
| MSCs (loaded with oHSV ) | ||
| Hepatocellular carcinoma | MSCs (infected with measles virus) | |
| Nanoparticle carriers | Solid tumor | NSCs (loaded with gold nanorods) |
| Glioma | MSCs (loaded with poly-lactic acid nanoparticles and lipid nanocapsules) | |
| MSCs (loaded with nanoparticles) | ||
| Regenerative medicine | Hematologic malignancies | HSCs (allogeneic transplantation) |
| Liver disease | iPSCs (engraftment of patient-specific iPSCs) | |
| Immunotherapy | Solid tumor | HSCs (induction of graft vs. tumor effect ) |
| Lymphomas | HSCs (allogeneic transplantation) | |
| iPSCs (generate T cells) | ||
| Melanoma | HSCs (genetically engineered HSCs to generate antigen-specific CD8 T cells) | |
| Targeting CSCs | Glioma | HSCs (modifying the proteome profile of HSCs ) |
| Anticancer drug screening | / | cancer tissue-derived iPSCs (provide cellular targets) |
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