Table 1.
Examination of cell lineages used as carriers for delivery of oncolytic viruses to malignancies. Advantages and disadvantages of each type of carrier are indexed, with citations of preclinical studies investigating these carriers listed adjacently.
| Type of Carrier | Advantages | Disadvantages | Reference |
|---|---|---|---|
| Transformed Cancer Cells | |||
| Solid Tumors | Often stimulate antitumor immunity. Support rapid replication of the viruses they carry. Easy to inject. |
Large size limits which tumor forms they can treat. Can cause new metastases. Administer low amounts of virus because of immediate immune responses upon injection. |
[18,19,20,21] |
| Hematopoietic and lymphoid tumors | Kinesis via the circulatory system. | Rapid proliferation rate can lead to de novo tumors. Elicit immune response, reducing amount of virus delivered. |
[15] |
| Xenogeneic/allogeneic | Injected cells are destroyed, preventing de novo metastases. | Immune response is profound, limits delivery because or side effects and rejection of injected cells. | [6] |
| Immune Cells | |||
| T cells | Home to metastases. Activated at tumor cite, release virus specifically into tumor. Do not elicit immune response. |
Strong preference to be loaded with reoviruses. Usually refractory to viral infection in vivo. |
[22,23,24] |
| Activated T Cells | Increased ability to take up viruses. Efficacy of viral treatments increases. |
Activation is lengthy and tedious. Do not support all viruses. |
[25,26] |
| CIKs | Home to tumors. Release high amounts of viruses upon reaching the tumor. Can affect a variety of tumor types. |
Requires expansion of primary leukocytes using cytokines in vivo. | [27] |
| Progenitor Cells | |||
| Blood outgrowth endothelial cells | Very targeted delivery because of ability to become incorporated into tumor neovasculature Divide successfully and rapidly in vivo. |
Cells are not immortal, new cells must be isolated from clinical samples. Currently unknown if they can support infection with replicating therapeutics. |
[28] |
| Mesenchymal Stem Cells | Migrate to the tumor tissue. Allow viral replication. Release virus upon interaction with tumor. Evade the immune system. |
High amount of non-specific migration in some cancers. Must be harvested from bone marrow. |
[29,30] |
| Neural Stem Cells | Specifically migrate to brain tumors. Allow viral replication. Evade the immune system. |
Require stereotactical extraction of cells from the subventricular zone. | [31,32,33] |