Table 1.
Summary of radioprotector/mitigator agents and their characteristics.
| Agent name | Agent type | Target tissue(s) | Mechanism(s) of action |
|---|---|---|---|
| Amifostine | Small-molecule (thiol) | Salivary glands mucosa | Free radical scavenger and other (see text) |
| Tetracycline | Small-molecule (antibiotic) | Bone marrow (HPC protector) | Unknown mechanism not related to its anti-microbial properties |
| Genistein | Small-molecule (soy isoflavone) | Bone marrow (HPC protector) | Multiple mechanisms (e.g., anti-inflammatory, antioxidant, free radical scanger, stimulator of DNA synthesis) |
| Captopril (also perindopril) | Small-molecule (anti-hypertensive drug) | Kidney protector, lung, bone marrow (HPC protector) | Angiotensin onverting enzyme (ACE) inhibitor, reduced inflammation; mechanism unclear |
| 3,3′-Diindolylmethane (DIM) | Small-molecule (indole derivative) | GI system bone marrow | Simulates ATM signaling and DNA damage response protection against oxidative stress |
| Rapamycin | Small-molecule (MTOR inhibitor) | Head and neck mucosa | MTOR inhibitor; blocks radiation-induced cellular senescence |
| ON01210/Ex-Rad | Small-molecule (chlorobenzyl sulfone derivative) | Bone marrow GI system | Tyrosine kinase inhibitor; attenuation of ATM/p53 signaling; up-regulation of PI3 kinase signaling |
| γ-Tocotrienol (GT3) | Small-molecule (vitamin E isomer) | Bone marrow (HPC protector) GI system | Antioxidant |
| δ-Tocotrienol | Small-molecule (vitamin E isomer) | Bone marrow | Antioxidant |
| Palliformin | Protein (keratinocyte growth factor) | Oral and esophageal mucosa | Stimulates epithelial cell proliferation; inhibits apoptosis |
| Superoxide dismutase (MnSOD) | Protein (enzyme, delivered by gene therapy approach) | Lung, esophagus, oral mucosa | Metabolizes ROS |
| CBLB502 (entolimod) | Protein (flagellin derivative) | GI system, bone marrow, skin, oral mucosa | TLR5 agonist; stimulates NF-κB signaling, induction of protective cytokines |
| TGF-β3 | Protein (transforming growth factor-β3) | Lung | Attenuates radiation-induced pulmonary function |
| R-spondin1 (Rspo1) | Protein (intestinal cell mitogen) | GI system | Accelerates regeneration of irradiated intestine through the Wnt/β-catenin pathway |
| Mesenchymal stem cell (MSC) transplant | Cellular therapy | Bone marrow various other tissues | Engraft and differentiation of MSCs; cytokine production; suppression of immune response and inflammation |
| Myeloid progenitor cells (MPCs) | Cellular therapy | Bone marrow GI system | HPC reconstitution; preserves structural integrity of the gut |
| Tocopherol succinate (TS)-mobilized progenitor cells | Cellular therapy | Bone marrow GI system | HPC reconstitution, bridging therapy; protection of the GI system |
| Bone marrow stromal cells | Cellular therapy | GI system | Increases blood levels of intestinal growth factors; induces regeneration of intestinal stem cells |