Stimulation of triple negative breast cancer cell migration and metastases formation is prevented by chloroquine in a pre-irradiated mouse model.
Some triple negative breast cancer (TNBC) patients are at higher risk of recurrence in the first three years after treatment. This rapid relapse has been suggested to be associated with inflammatory mediators induced by radiation in healthy tissues that stimulate cancer cell migration and metastasis formation. In this study, the ability of chloroquine (CQ) to inhibit radiation-stimulated development of metastasis was assessed.



The capacity of CQ to prevent radiation-enhancement of cancer cell invasion was assessed in vitro with the TNBC cell lines D2A1, 4T1 and MDA-MB-231 and the non-TNBC cell lines MC7-L1, and MCF-7. In Balb/c mice, a single mammary gland was irradiated with four daily doses of 6 Gy. After the last irradiation, irradiated and control mammary glands were implanted with D2A1 cells. Mice were treated with CQ (vehicle, 40 or 60 mg/kg) 3 h before each irradiation and then every 72 h for 3 weeks. Migration of D2A1 cells in the mammary gland, the number of circulating tumor cells and lung metastasis were quantified, and also the expression of some inflammatory mediators.



Irradiated fibroblasts have increased the invasiveness of the TNBC cell lines only, a stimulation that was prevented by CQ. On the other hand, invasiveness of the non-TNBC cell lines, which was not enhanced by irradiated fibroblasts, was also not significantly modified by CQ. In Balb/c mice, treatment with CQ prevented the stimulation of D2A1 TNBC cell migration in the pre-irradiated mammary gland, and reduced the number of circulating tumor cells and lung metastases. This protective effect of CQ was associated with a reduced expression of the inflammatory mediators interleukin-1β, interleukin-6, and cyclooxygenase-2, while the levels of matrix metalloproteinases-2 and -9 were not modified. CQ also promoted a blocking of autophagy.



CQ prevented radiation-enhancement of TNBC cell invasion and reduced the number of lung metastases in a mouse model.
Centre for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Québec, J1H 5 N4, Canada.
Gina
G
Bouchard
Centre for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Québec, J1H 5 N4, Canada.
Hélène
H
Therriault
Department of Pathology, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada.
Sameh
S
Geha
Department of Electrical and Computer Engineering, Centre d'imagerie moléculaire de Sherbrooke, Sherbrooke, Québec, Canada.
Yves
Y
Bérubé-Lauzière
Centre for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Québec, J1H 5 N4, Canada.|Service of Radiation Oncology, Université de Sherbrooke, Sherbrooke, Canada.
Rachel
R
Bujold
Department of Anatomy and Cellular Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Canada.
Caroline
C
Saucier
Centre for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Québec, J1H 5 N4, Canada. Benoit.Paquette@USherbrooke.ca.
Benoit
B
Paquette
D000818:Animals; D001343:Autophagy / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D002738:Chloroquine / Q000008:administration & dosage* / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007378:Interleukins / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000556:secondary; D061986:MCF-7 Cells; D020782:Matrix Metalloproteinases / Q000378:metabolism; D051379:Mice; D009362:Neoplasm Metastasis; D009360:Neoplastic Cells, Circulating / Q000187:drug effects*; D016896:Treatment Outcome; D064726:Triple Negative Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000532:radiotherapy*; D023041:Xenograft Model Antitumor Assays
D007378:Interleukins; D002738:Chloroquine; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D020782:Matrix Metalloproteinases
Chloroquine; Inflammation; Invasion; Metastasis; Radiation; Triple negative breast cancer