Abstract 1967: Nab-paclitaxel chemotherapy of breast tumors upregulates chemokines that increase chemotaxis of myeloid-lymphatic progenitors
Year: 2019
Type: conference-abstract
Abstract: Introduction: Lymph node metastasis is the main prognostic indicator for poor survival of breast cancer patients. Metastasis is promoted by tumor-induced lymphangiogenesis mediated, in part, through recruitment of myeloid-derived lymphatic endothelial cell progenitors (M-LECP). We previously showed that differentiation of M-LECP is induced by activated Toll-like receptor-4 (TLR4). The goal of this study was to identify TLR4-induced chemokines produced by tumors alone or in response to nab-paclitaxel (nab-PXL) chemotherapy that enhance bone marrow (BM) differentiation and tumor recruitment of M-LECP.Methods: Profile of BM composition for lymphatic-like, myeloid and progenitor cells was assessed by flow cytometry in normal and tumor-bearing mice treated either with saline or nab-PXL. We used two TLR4 overexpressing tumor models: MDA-MB-231 and HCC1806-TLR4+. RT-qPCR was used to determine differences in expression of 130 cytokines in cultured tumor cells and tumors from mice treated either with saline or nab-PXL. Targets with >2-fold upregulation were analyzed for protein expression by ELISA. ELISA-validated cytokines were tested for their ability to induce migration of M-LECP.Results: Both MDA-MB-231 or HCC1806-TLR4+ tumors significantly increased the levels of differentiated M-LECP in the BM, and that was further enhanced by treatment with taxane chemotherapy. Expression of progenitor markers CD117, CD33, and Sca-1 was increased up to 7-fold in both tested tumor models, and further upregulated by nab-PXL treatment by additional 3 to 9-fold. Out of 23 cytokines measured in tumor lysates by ELISA, 40% were upregulated by nab-PXL. Migration assay showed that several of these cytokines increased chemotaxis of M-LECP with CXCL1 being the strongest. Neutralization of CXCL1 in the conditioned medium of nab-PXL-treated MDA-MB-231 cells inhibited migration of lymphatic progenitors by 75%.Conclusion: Taxane chemotherapy acting presumably as a ligand for TLR4 significantly expanded M-LECP population in the BM. Our analysis suggests that these lymphatic precursors can mobilize to tumors by chemokines such as CXCL1 that are highly upregulated in TLR4-positive tumor cells, particularly when activated by paclitaxel. These data suggest that CXCL1 plays an important role in recruiting myeloid-lymphatic progenitors to breast tumors, which, in turn, promotes lymphatic vessel formation and metastasis. Blocking this cytokine might have clinical utility for prevention of tumor mobilization of M-LECP, and by extension, breast cancer metastasis to lymph nodes.Citation Format: Lisa D. Volk-Draper, Sophia Ran. Nab-paclitaxel chemotherapy of breast tumors upregulates chemokines that increase chemotaxis of myeloid-lymphatic progenitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1967.
Source: Tumor Biology
Authors: Lisa D. Volk-Draper, Sophia Ran
Institution: SIU Medicine
Language: English
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $1,500
OpenAlex ID: W2955476490