RESUMO
PURPOSE: We have previously reported that protracted Cyclooxygenase-2 (COX-2) activity in bone marrow-derived cells (BMDCs) infiltrating into biopsy wounds adjacent to the biopsy cavity of breast tumors in mice promotes M2-shift of macrophages and pro-metastatic changes in cancer cells, effects which were suppressed by oral administration of COX-2 inhibitors. Thus, local control of COX-2 activity in the biopsy wound may mitigate biopsy-induced pro-metastatic changes. METHODS: A combinatorial delivery system-thermosensitive biodegradable poly(lactic acid) hydrogel (PLA-gel) incorporating celecoxib-encapsulated poly(lactic-co-glycolic acid) nanoparticles (Cx-NP/PLA-gel)-was injected into the biopsy cavity of Py230 murine breast tumors to achieve local control of COX-2 activity in the wound stroma. RESULTS: A single intra-biopsy cavity injection of PLA-gel loaded with rhodamine-encapsulated nanoparticles (NPs) showed sustained local delivery of rhodamine preferentially to infiltrating BMDCs with minimal to no rhodamine uptake by the reticuloendothelial organs in mice. Moreover, significant reductions in M2-like macrophage density, cancer cell epithelial-to-mesenchymal transition, and blood vessel density were observed in response to a single intra-biopsy cavity injection of Cx-NP/PLA-gel compared to PLA-gel loaded with NPs containing no payload. Accordingly, intra-biopsy cavity injection of Cx-NP/PLA-gel led to significantly fewer metastatic cells in the lungs than control-treated mice. CONCLUSION: This study provides evidence for the feasibility of sustained, local delivery of payload preferential to BMDCs in the wound stroma adjacent to the biopsy cavity using a combinatorial delivery system to reduce localized inflammation and effectively mitigate breast cancer cell dissemination.
RESUMO
Increased breast cancer (BC) mortality risk posed by delayed surgical resection of tumor after diagnosis is a growing concern, yet the underlying mechanisms remain unknown. Our cohort analyses of early-stage BC patients reveal the emergence of a significantly rising mortality risk when the biopsy-to-surgery interval was extended beyond 53 days. Additionally, histology of post-biopsy tumors shows prolonged retention of a metastasis-permissive wound stroma dominated by M2-like macrophages capable of promoting cancer cell epithelial-to-mesenchymal transition and angiogenesis. We show that needle biopsy promotes systemic dissemination of cancer cells through a mechanism of sustained activation of the COX-2/PGE2/EP2 feedforward loop, which favors M2 polarization and its associated pro-metastatic changes but are abrogated by oral treatment with COX-2 or EP2 inhibitors in estrogen-receptor-positive (ER+) syngeneic mouse tumor models. Therefore, we conclude that needle biopsy of ER+ BC provokes progressive pro-metastatic changes, which may explain the mortality risk posed by surgery delay after diagnosis.