title: The Yin/Yan of CCL2: a minor role in neutrophil anti-tumor activity in vitro but a major role on the outgrowth of metastatic breast cancer lesions in the lung in vivo.
abstract: The role of the chemokine CCL2 in breast cancer is controversial. While CCL2 recruits and activates pro-tumor macrophages, it is also reported to enhance neutrophil-mediated anti-tumor activity. Moreover, loss of CCL2 in early development enhances breast cancer progression.
  
  
  
  To clarify these conflicting findings, we examined the ability of CCL2 to alter naïve and tumor entrained neutrophil production of ROS, release of granzyme-B, and killing of tumor cells in multiple mouse models of breast cancer. CCL2 was delivered intranasally in mice to elevate CCL2 levels in the lung and effects on seeding and growth of breast tumor cells were evaluated. The TCGA data base was queried for relationship between CCL2 expression and relapse free survival of breast cancer patients and compared to subsets of breast cancer patients.
  
  
  
  Even though each of the tumor cell lines studied produced approximately equal amounts of CCL2, exogenous delivery of CCL2 to co-cultures of breast tumor cells and neutrophils enhanced the ability of tumor-entrained neutrophils (TEN) to kill the less aggressive 67NR variant of 4T1 breast cancer cells. However, exogenous CCL2 did not enhance naïve or TEN neutrophil killing of more aggressive 4T1 or PyMT breast tumor cells. Moreover, this anti-tumor activity was not observed in vivo. Intranasal delivery of CCL2 to BALB/c mice markedly enhanced seeding and outgrowth of 67NR cells in the lung and increased the recruitment of CD4+ T cells and CD8+ central memory T cells into lungs of tumor bearing mice. There was no significant increase in the recruitment of CD19+ B cells, or F4/80+, Ly6G+ and CD11c + myeloid cells. CCL2 had an equal effect on CD206+ and MHCII+ populations of macrophages, thus balancing the pro- and anti-tumor macrophage cell population. Analysis of the relationship between CCL2 levels and relapse free survival in humans revealed that overall survival is not significantly different between high CCL2 expressing and low CCL2 expressing breast cancer patients grouped together. However, examination of the relationship between high CCL2 expressing basal-like, HER2+ and luminal B breast cancer patients revealed that higher CCL2 expressing tumors in these subgroups have a significantly higher probability of surviving longer than those expressing low CCL2.
  
  
  
  While our in vitro data support a potential anti-tumor role for CCL2 in TEN neutrophil- mediated tumor killing in poorly aggressive tumors, intranasal delivery of CCL2 increased CD4+ T cell recruitment to the pre-metastatic niche of the lung and this correlated with enhanced seeding and growth of tumor cells. These data indicate that effects of CCL2/CCR2 antagonists on the intratumoral leukocyte content should be monitored in ongoing clinical trials using these agents.
authors.affiliation: Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA.|Department of Cancer Biology, Vanderbilt University Medical Center, 432 Preston Research Building, 2220 Pierce Avenue, Nashville, TN, 37232, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Lavender
authors.affiliation: Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA.|Department of Cancer Biology, Vanderbilt University Medical Center, 432 Preston Research Building, 2220 Pierce Avenue, Nashville, TN, 37232, USA.
authors.forename: Jinming
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Cancer Biology, Vanderbilt University Medical Center, 432 Preston Research Building, 2220 Pierce Avenue, Nashville, TN, 37232, USA.|Division of Cancer Biostatistics, Department of Biostatistics, Center for Quantitative Sciences, Nashville, TN, USA.
authors.forename: Sheau-Chiann
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA.|Department of Cancer Biology, Vanderbilt University Medical Center, 432 Preston Research Building, 2220 Pierce Avenue, Nashville, TN, 37232, USA.
authors.forename: Jiqing
authors.initials: J
authors.lastname: Sai
authors.affiliation: Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA.|Department of Cancer Biology, Vanderbilt University Medical Center, 432 Preston Research Building, 2220 Pierce Avenue, Nashville, TN, 37232, USA.
authors.forename: C Andrew
authors.initials: CA
authors.lastname: Johnson
authors.affiliation: Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA.|Department of Cancer Biology, Vanderbilt University Medical Center, 432 Preston Research Building, 2220 Pierce Avenue, Nashville, TN, 37232, USA.
authors.forename: Philip
authors.initials: P
authors.lastname: Owens
authors.affiliation: Department of Biostatistics, Vanderbilt University, Nashville, TN, USA.|Division of Cancer Biostatistics, Department of Biostatistics, Center for Quantitative Sciences, Nashville, TN, USA.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Ayers
authors.affiliation: Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA. ann.richmond@vanderbilt.edu.|Department of Cancer Biology, Vanderbilt University Medical Center, 432 Preston Research Building, 2220 Pierce Avenue, Nashville, TN, 37232, USA. ann.richmond@vanderbilt.edu.
authors.forename: Ann
authors.initials: A
authors.lastname: Richmond
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000378:metabolism*; D018920:Coculture Techniques; D004195:Disease Models, Animal; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000378:metabolism / Q000473:pathology; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology*; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000378:metabolism* / Q000473:pathology*
chemical_list: D018932:Chemokine CCL2
keywords: Breast cancer; CCL2; Metastasis; Neutrophil killing