Whole blueberry powder inhibits metastasis of triple negative breast cancer in a xenograft mouse model through modulation of inflammatory cytokines.

Triple negative breast cancer (TNBC) comprises approximately 15% of breast cancers and is associated with a poor prognosis. Many patients with TNBC relapse quickly and commonly develop metastases. There are no individualized targeted adjuvant or induction treatments for TNBC, and the current treatments are highly toxic. Development of chemoprevention methods using natural products would be beneficial to patients at risk of TNBC. To investigate the inhibitory effect of blueberries on inflammation-induced TNBC and identify the mechanism underlying modulation of inflammatory proteins by blueberries, we induced a proinflammatory microenvironment by feeding female MDA-MB-231 tumor-bearing mice a high fat western diet (W) with 5% whole blueberry powder (BB) and studied the effect on tumor formation and metastasis. We showed that mice fed a BB diet had significantly smaller tumors, less ulceration, and significantly less metastasis to the inguinal lymph nodes than mice fed a W diet. In BB-fed mice, serum levels of specific antiinflammatory cytokines were increased and specific cytokine expression was also altered. Together, these results suggest that blueberries may inhibit TNBC and TNBC-related metastasis by reducing inflammation via specific cytokine-driven pathways and thus reduce tumor growth and metastasis.