Breast Cancer Cell Line Aggregate Morphology Does Not Predict Invasive Capacity

Michelle J Ziperstein,Asja Guzman,Laura J Kaufman,Natarajan Aravindan

doi:10.1371/journal.pone.0139523

Abstract

To invade and metastasize to distant loci, breast cancer cells must breach the layer of basement membrane surrounding the tumor and then invade through the dense collagen I-rich extracellular environment of breast tissue. Previous studies have shown that breast cancer cell aggregate morphology in basement membrane extract correlated with cell invasive capacity in some contexts. Moreover, cell lines from the same aggregate morphological class exhibited similarities in gene expression patterns. To further assess the capacity of cell and aggregate morphology to predict invasive capacity in physiologically relevant environments, six cell lines with varied cell aggregate morphologies were assessed in a variety of assays including a 3D multicellular invasion assay that recapitulates cell-cell and cell-environment contacts as they exist in vivo in the context of the primary breast tumor. Migratory and invasive capacities as measured through a 2D gap assay and a 3D spheroid invasion assay reveal that breast cancer cell aggregate morphology alone is insufficient to predict migratory speed in 2D or invasive capacity in 3D. Correlations between the 3D spheroid invasion assay and gene expression profiles suggest this assay as an inexpensive functional method to predict breast cancer invasive capacity.

Highlights

Despite critical improvements in treatment and a strong trend towards early diagnosis in developed countries, breast cancer continues to be a leading cause of death worldwide
Six breast cancer cell lines were investigated in this work, three that were previously identified as demonstrating stellate aggregate morphology (MDA-MB-231, Hs 578T, MDA-MB-157) and three that were identified as demonstrating grape-like aggregate morphology (MDA-MB468, ZR-75-1, and MDA-MB-453 cells) in lamininrich extracellular matrix (lrECM) [18]
We found that aggregate morphology of six breast cancer cell lines within 3D collagen I gels was very similar to that in lrECM, though we categorized ZR-75-1 as exhibiting mass aggregates rather than grape-like aggregates

Summary

Introduction

Despite critical improvements in treatment and a strong trend towards early diagnosis in developed countries, breast cancer continues to be a leading cause of death worldwide. Almost all such deaths result from breast cancer metastasis to distant organs whose critical functions are compromised. This cancer progression occurs in several stages, but all localized breast cancers that become metastatic must invade locally before the intravasation that leads to metastasis to distant sites. Given that localized breast cancers can only become metastatic if they can breach the basement membrane and invade collagen I-rich environments, either basement membrane or collagen I may be an appropriate in vitro environment in which to assess a breast cancer’s ability to PLOS ONE | DOI:10.1371/journal.pone.0139523 September 29, 2015

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Conclusion