Table 2.
Possible therapy strategies for CAC based on MDSC regulation
| Strategies | Events | Subsets | Models | References |
| Gemcitabine | Reduce intratumoral MDSCs. | MDSCs | mHer2/CT-26-bearing mice | 92 |
| Oxaliplatin and IL-12 | Reduce intratumoral MDSCs. | MDSCs | MC-38 liver metastasis model | 93 |
| 5-FU, oxaliplatin, and bevacizumab | Decrease G-MDSCs in the peripheral blood. | G-MDSCs | Patients with mCRC | 94 |
| 5-FU, folinic acid, bevacizumab, and anakinra | Decrease M-MDSCs in the peripheral blood. | M-MDSCs | Patients with mCRC | 95 |
| 5-FC and Toca 511 | Decrease MDSCs in both the liver and brain. | MDSCs | CT-26 liver and brain metastasis model | 96 |
| Anti-SEMA4D Ab (VX15/2503) | Inhibit MDSC expansion. | MDSCs | Patients with mCRC | 101 |
| Anti-cKit Ab | Prevent MDSC accumulation through blocking cKit-SCF interactions. | MDSCs | MCA-26-bearing mice | 102 |
| Anti-CCR2 Ab | Block radiation-induced MDSC infiltration. | M-MDSCs | MC-38-bearing mice | 103 |
| OX40 agonist | Reduce intratumoral MDSCs. | MDSCs | CT-26-bearing mice | 104 |
| Pembrolizumab | – | – | Patients with MSI-H+ CRC | 105 |
| Nivolumab | – | – | Patients with MSI-H+ mCRC | 106 |
| Radiation | Reduce intratumoral MDSCs. | MDSCs | CT-26 and MC-38-bearing mice | 117 |
| Nitroaspirin | Decrease the recruitment or survival of intratumoral MDSCs, and Arg-1, NOS2, PNT expression. | MDSCs | CT-26-bearing mice | 118 |
| PDE-5 inhibitors (sildenafil and tadalafil) |
Decrease the recruitment of intratumoral MDSCs and Arg-1, NOS2 expression. | G-MDSCs | CAC mice | 107 |
| Triterpenoids | Inhibit ROS expression. | MDSCs | MC-38-bearing mice | 108 |
| Etomoxir | Block the immunosuppressive functions of MDSCs. | MDSCs | MC-38-bearing mice | 109 |
| GSK872 | Reduce circulating MDSCs by inhibiting RIPK3 signaling. | MDSCs | APCmin/+ mice, MC-38-bearing mice |
110 |
| Metformin | Inhibit the immunosuppressive functions of G-MDSCs by reducing p-STAT3 levels. | G-MDSCs | CT-26-bearing mice | 111 |
| Fluconazole | Decrease MDSC accumulation. | MDSCs | CAC mice | 50 |
| TFF2 | Arrest MDSC proliferation. | MDSCs | CAC mice | 22 |
| EZH2 inhibitor | Promote MDSC generation from progenitor cells during IBD. | MDSCs | CAC mice | 89 |
| Juglone | Decrease MDSC accumulation. | MDSCs | CT-26-bearing mice | 112 |
| Hyperoxia | Suppress G-MDSC-derived exosome production. | G-MDSCs | CAC mice | 12 |
Ab, antibody; Arg-1, arginase 1; CAC, colitis-associated cancer; CCR2, chemokine (C-C motif) receptor 2; c-Kit, cellular kit proto-oncogene; EZH2, enhancer of zeste homolog 2; 5-FC, 5-fluorocytosine; 5-FU, 5-fluorouracil; G-MDSCs, granulocytic MDSCs; IBD, inflammatory bowel disease; IL, interleukin; mCRC, metastatic colorectal cancer; MDSCs, myeloid-derived suppressor cells; M-MDSCs, monocytic MDSCs; MSI-H, microsatellite instability-high; OX40, oxford 40; PDE-5, phosphodiesterase 5; PNT, peroxynitrite; RIPK3, receptor interacting protein kinase 3; ROS, reactive oxygen species; SEMA4D, semaphorin 4D; STAT3, signal transducer and activator of transcription 3; TFF2, trefoil factor 2.