Leptin produced by obesity-altered adipose stem cells promotes metastasis but not tumorigenesis of triple-negative breast cancer in orthotopic xenograft and patient-derived xenograft models

Rachel A. Sabol,
Annie C. Bowles,
Alex Côté,
Rachel Wise,
Benjamen O’Donnell,
Margarite D. Matossian,
Fokhrul M. Hossain,
Hope E. Burks,
Luis Del Valle,
Lucio Miele,
Bridgette M. Collins-Burow,
Matthew E. Burow and
Bruce A. BunnellEmail author

Breast Cancer Research201921:67

https://doi.org/10.1186/s13058-019-1153-9

Received: 4 October 2018
Accepted: 7 May 2019
Published: 22 May 2019

Abstract

Background

Breast cancer is the second leading cause of cancer deaths in the USA. Triple-negative breast cancer (TNBC) is a clinically aggressive subtype of breast cancer with high rates of metastasis, tumor recurrence, and resistance to therapeutics. Obesity, defined by a high body mass index (BMI), is an established risk factor for breast cancer. Women with a high BMI have increased incidence and mortality of breast cancer; however, the mechanisms(s) by which obesity promotes tumor progression are not well understood.

Methods

In this study, obesity-altered adipose stem cells (obASCs) were used to evaluate obesity-mediated effects of TNBC. Both in vitro and in vivo analyses of TNBC cell lines were co-cultured with six pooled donors of obASCs (BMI > 30) or ASCs isolated from lean women (lnASCs) (BMI < 25).

Results

We found that obASCs promote a pro-metastatic phenotype by upregulating genes associated with epithelial-to-mesenchymal transition and promoting migration in vitro. We confirmed our findings using a TNBC patient-derived xenograft (PDX) model. PDX tumors grown in the presence of obASCS in SCID/beige mice had increased circulating HLA1+ human cells as well as increased numbers of CD44+CD24− cancer stem cells in the peripheral blood. Exposure of the TNBC PDX to obASCs also increased the formation of metastases. The knockdown of leptin expression in obASCs suppressed the pro-metastatic effects of obASCs.