Table 5.
Summary of CCL2's effects on macrophages in cancer.
| Effect on macrophages | Source of CCL2 or CCL2/CCR2 blocking/KO | Cells/model | Methods and results | Tumor type | References |
|---|---|---|---|---|---|
| MATURATION/DIFFERENTIATION/CYTOKINE PRODUCTION | |||||
| Promotes M2 phenotype | Anti-CCL2 Ab + Anti-CCL12 Ab | m flank tumor model +/– blocking Abs | Blocking Abs: M2 marker CD206↓ (FC), Blocking Abs: M1 marker iNOS↑, M2 markers FcR1↓, CD206↓, Arg1↓ (RT-PCR) | NSCLC | (120) |
| SN of tumor cells, rCCL2 | Coculture of RAW264.7 macrophages and 4T1 m breast cancer cells | M2 marker CD206↑ (FC) | Breast cancer | (121) | |
| CM of tumor cells, CCR2 antagonist, anti-CCL2 Ab | m BMDM and CM of Hepa1-6 cells | M2 markers Arg1↑, IL-10↑, M1 markers iNOS↓, IL12↓, immune suppressive cytokines: G-CSF↑, MIP-1↑, MIP-2↑, CCL2 blocking or CCR2 antagonist: effects reversed (RT-PCR) | Hepatocellular carcinoma | (122) | |
| SACC-83 (adenoid cystic carcinoma cell line) CM, CCR2 antagonist RS504393 | Macrophages derived from THP-1 cells treated with PMA +/– RS504393 + CM, murine SACC-83 xenograft model +/- RS504393 |
Macrophages with SACC-83 CM: M2 marker CD163↑, CD206↑ (FC), M2 marker Arg1↑, IL-10↑, M1 marker TNFα↓, IL-1β↓ (RT-PCR), GDNF expression↑ (RT-PCR, WB, ELISA), in presence of RS504393: M1 markers Arg1 and IL-10↓ (RT-PCR), murine SACC-83 xenograft model + RS504393: tumor associated M2 macrophages CD163↓ (immunohistochemical cell counts) |
Adenoid cystic carcinoma | (123) | |
| Cytokine production | CCR2 antagonist | m flank tumor model +/– CCR2 antagonist | CCR2 antagonist: immune suppressive cytokines↓ (cytokine profiling of sorted (F4/80, CD11b, CD206) macrophages) | Hepatocellular carcinoma | (122) |
| Anti-CCL2 Ab | TAM isolated from mammary tumors +/– anti-CCL2 Ab | blocking CCL2: IL-1β↓, marker genes (=) (Arg1, CD206, decoy IL1R2, iNOS), inducers of IL-17 (=) [TGFβ, IL-6, Il23p19)] (RT-PCR) | Breast cancer | (124) | |
| SN of tumor cells (+/– transfected with antisense CCL2), rCCL2 | PEMs (activated and resting) or isolated TAM + 4T1 cell SNs or rCCL2 | PEMs + tumor-derived CCL2: proinflammatory cytokines TNFα ↑, IL18↑, IL-12 not detectable (RT-PCR), rCCL2 treatment of PEMs: IL12↑ (ELISA), TAM from tumors +/– CCL2: IL12 (=), TNFα (=), IL18 (=) (ELISA) |
Breast cancer | (125) | |
| Proliferation and polarization | rCCL2, anti-CCL2 Ab, PI3K-Akt inhibitor, Erk1/2 inhibitor | h macrophages stimulated with M-CSF +/– cocultured in Transwell system with ARP-1 or MM.1S MM cells to obtain MM-associated macrophages | Blocking CCL2: proliferation↓, adding rCCL2: proliferation↑, blocking PI3K-Akt and ERK1/2: proliferation↓ (MTS assay) adding rCCL2: phosphorylation of different kinases↑, IL-6 (=), c-myc↑, cyclin D1↑, p27Kip1↓ (WB) |
Multiple myeloma | (126) |
| ACTIVATES KILLING | |||||
| Primes macrophages to become tumoricidal together with LPS | Tumor cells transfected +/– CCL2, tumor cell SN, Anti-CCL2-Ab | PEMs (+/–LPS) and CT26 tumor cells (+/–CCL2 transfected), +/– anti-CCL2 Ab | Cytotoxicity in presence of CCL2↑, blocking CCL2: cytotoxicity↓ (release of radioactivity from target cell DNA) | Colon carcinoma | (127) |
| Tumor cells transfected +/– CCL2, rCCL2 | PEMs (+/–LPS) and melanoma and fibrosarcoma tumor cells (syngeneic) | Cytotoxicity ↑(release of radioactivity from target cell DNA) | Melanoma | (128) | |
| SN of NIH3T3, Anti-CCL2 Ab, rCCL2 | PEMs and RENCA cells + SN of CCL2-transfected NIH3T3 +/– LPS, +/– anti-CCL2-Ab or rCCL2, alveolar macrophages isolated +/– after injection of CCL2-transfected NIH3T3 and RENCA cells |
Cytotoxicity in presence of CCL2 ↑, blocking of CCL2: cytotoxicity↓ (release of radioactivity from target cell DNA) | Renal adenocarcinoma | (129) | |
| In vivo model | Injection of adenocarcinoma cells transfected +/–CCL2 complementary DNA +/- LPS i.p. | CCL2 + LPS: tumor size↓ (measuring footpad/tumor size) | Adenocarcinoma | (130) | |
| Increases macrophage-mediated cytotoxicity | rCCL2, MEK inhibitor PD98059 | PEMs cells + P815 (m mastocytoma) cells + rCCL2 +/– PD98059, PEMs + rCCL2 |
Cytotoxicity with rCCL2↑, with PD98059↓ (release of radioactivity from target cell DNA), PEMs with rCCL2: Phospho-p42/44 MAPK↑, phospho-JNK↑, phospho-c-Jun↑ (WB) |
Inflammation and tumor growth | (113) |
| No direct influence on macrophage-mediated anti-tumor activity | SN of tumor cells (+/– transfected with antisense CCL2) | PEMs (activated and resting) from female Balb/c mice + 4T1 tumor cell SNs | Phagocytic activity (=) (phagocytosis assay), cytotoxicity (=) (cytolytic activity assay), nitric oxide levels (=) (colorimetric detection) |
Breast cancer | (125) |
Ab, antibody; BMDM, bone-marrow-derived macrophage; CM, conditioned medium; FACS, fluorescence-activated cell sorting; FC, flow cytometry; h, human; KO, knockout; m, murine; MM, multiple myeloma; NSCLC, non-small cell lung cancer; PEM, peritoneal exudate macrophage; RT-PCR, reverse transcription PCR; rCCL2, recombinant CCL2; SSC, side scatter; SN, supernatant; TAM, tumor-associated macrophage; WB, Western blot; ↑, upregulation; ↓, downregulation; (=), level stays the same.