Whole blueberry powder modulates the growth and metastasis of MDA-MB-231 triple negative breast tumors in nude mice.

Authors – Adams LS,  Kanaya N,  Phung S,  Liu Z,  Chen S.

Abstract

Previous studies in our laboratory demonstrated that blueberry (BB) extract exhibited antitumor activity against MDA-MB-231 triple negative breast cancer (TNBC) cells and decreased metastatic potential in vitro.

The current study tested 2 doses of whole BB powder, 5 and 10% (wt:wt) in the diet, against MDA-MB-231 tumor growth in female nude mice. In this study, tumor volume was 75% lower in mice fed the 5% BB diet and 60% lower in mice fed the 10% BB diet than in control mice (P ≤ 0.05).

Tumor cell proliferation (Ki-67) was lower in the 5 and 10% BB-fed mice and cell death (Caspase 3) was greater in the 10% BB-fed mice compared to control mice (P ≤ 0.05).

Gene analysis of tumor tissues from the 5% BB-fed mice revealed significantly altered expression of genes important to inflammation, cancer, and metastasis, specifically, Wnt signaling, thrombospondin-2, IL-13, and IFNγ. To confirm effects on Wnt signaling, analysis of tumor tissues from 5% BB-fed mice revealed lower β-catenin expression and glycogen synthase kinase-3β phosphorylation with greater expression of the β-catenin inhibitory protein adenomatous polyposis coli compared to controls.

A second study tested the ability of the 5% BB diet to inhibit MDA-MB-231-luc-D3H2LN metastasis in vivo. In this study, 5% BB-fed mice developed 70% fewer liver metastases (P = 0.04) and 25% fewer lymph node metastases (P = 0.09) compared to control mice.

This study demonstrates the oral antitumor and metastasis activity of whole BB powder against TNBC in mice.

MDA-MB-231 tumor volume (A), proliferation (B), and apoptosis (C) in female nude mice fed control, 5% BB powder, or 10% BB powder diet for 8 wk. Data are means ± SEM, n = 6. In A, labeled means at a time without a common letter differ, P ≤ 0.05. In B and C, asterisks indicate different from control: *P ≤ 0.05, **P ≤ 0.01. BB, blueberry.
In situ tumor growth and metastasis monitored by Xenogen IVIS imaging at different time points after MDA-MB-231 tumor implantation in female nude mice fed control or 5% BB diet for 7 wk. (A) Orthotopic breast tumor growth from baseline to wk 5 postimplantation. (B) In situ and ex-vivo imaging of RLN and LLN lymph node metastasis at wk 5 postimplantation. (C) Frequency of metastasis and mean intensity of liver and LN metastases analyzed by contingency table. Intensity data are mean ± SEM for the number of mice with metastases. *Different from control, P ≤ 0.05. BB, blueberry; LLN, left lymph node; RLN, right lymph node.

Source : https://www.ncbi.nlm.nih.gov/pubmed/21880954

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