New generation breast cancer cell lines developed from patient-derived xenografts

Jessica Finlay-Schultz,Scott Turner,Peter Kabos,Kiran V Paul,Carol A Sartorius,Andrea Ferreira-Gonzalez,Britta M Jacobsen,J Chuck Harrell,Duncan Riley

doi:10.1186/s13058-020-01300-y

Abstract

BackgroundBreast cancer is a highly heterogeneous disease characterized by multiple histologic and molecular subtypes. While a myriad of breast cancer cell lines have been developed over the past 60 years, estrogen receptor alpha (ER)+ disease and some mutations associated with this subtype remain underrepresented. Here we describe six breast cancer cell lines derived from patient-derived xenografts (PDX) and their general characteristics.MethodsEstablished breast cancer PDX were processed into cell suspensions and placed into standard 2D cell culture; six emerged into long-term passageable cell lines. Cell lines were assessed for protein expression of common luminal, basal, and mesenchymal markers, growth assessed in response to estrogens and endocrine therapies, and RNA-seq and oncogenomics testing performed to compare relative transcript levels and identify putative oncogenic drivers.ResultsThree cell lines express ER and two are also progesterone receptor (PR) positive; PAM50 subtyping identified one line as luminal A. One of the ER+PR+ lines harbors a D538G mutation in the gene for ER (ESR1), providing a natural model that contains this endocrine-resistant genotype. The third ER+PR−/low cell line has mucinous features, a rare histologic type of breast cancer. The three other lines are ER− and represent two basal-like and a mixed ductal/lobular breast cancer. The cell lines show varied responses to tamoxifen and fulvestrant, and three were demonstrated to regrow tumors in vivo. RNA sequencing confirms all cell lines are human and epithelial. Targeted oncogenomics testing confirmed the noted ESR1 mutation in addition to other mutations (i.e., PIK3CA, BRCA2, CCND1, NF1, TP53, MYC) and amplifications (i.e., FGFR1, FGFR3) frequently found in breast cancers.ConclusionsThese new generation breast cancer cell lines add to the existing repository of breast cancer models, increase the number of ER+ lines, and provide a resource that can be genetically modified for studying several important clinical breast cancer features.

Highlights

Breast cancer is a highly heterogeneous disease characterized by multiple histologic and molecular subtypes
Generation of six breast cancer cell lines from patient-derived xenografts (PDX) that span diverse phenotypes Given the relative dearth of estrogen receptor alpha (ER)+progesterone receptor (PR)+ cell lines in proportion to the > 75% of patients with this diagnosis, one of our primary goals was to focus on this subtype for generating long-term cultures
Three of the PDX-derived cell lines are developed from metastases and three from primary tumors

Summary

Introduction

Breast cancer is a highly heterogeneous disease characterized by multiple histologic and molecular subtypes. While a myriad of breast cancer cell lines have been developed over the past 60 years, estrogen receptor alpha (ER)+ disease and some mutations associated with this subtype remain underrepresented. We describe six breast cancer cell lines derived from patient-derived xenografts (PDX) and their general characteristics. Existing human breast cancer cell lines, patient-derived xenografts (PDX), patient-derived organoids (PDO), and murine models with intact immune systems capture many of these unique histopathological, molecular, and genetic subtypes. We describe generation of six PDX-derived breast cancer cell lines including three ER+ lines, one with ESR1 mutation, that add to the collection of research models available to investigators

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