Title

Androgen receptor expressing metaplastic carcinoma cell line established from non-caucasian female patient

Document Type

Article

Department

Pathology and Laboratory Medicine

Abstract

Background:Metaplastic carcinoma (MCa) is a rare entity of breast cancer (BCa) where tumor of epithelial origin manifests differentiation into non-glandular, mesenchymal phenotype. These tumors exhibit heterogeneity with spindle, squamous, chondroid or osseous differentiation. Majority of these tumors do not express estrogen or progesterone receptors and are negative for HER-2/neu gene amplification, limiting use of available targeted therapies. This may translate into poor clinical outcome in this subset of patients as opposed to triple negative subtype of breast cancer. Cancer cell lines have been proved to be a valuable tool in understanding pathogenesis of BCa and development of appropriate drugs. Considering tumor heterogeneity, selecting an appropriate cell line model is imperative to understand signaling mechanisms of each of the distinct sub-types of BCa.Aim of this study was to establish and characterize a BCa cell line from a non-caucasian Pakistani patient.
Methodology:Cell line was established from primary culture of tumor tissue from a 65 year old Pakistani female patient diagnosed with T4N1M0 MCa of breast. Specimen was procured in Dulbecco's Modified Eagle's Medium and processed under sterile conditions by mincing and gentle pipetting followed by culturing in complete medium supplemented with 10% fetal bovine serum. Epitheliod colonies were visualized after 3 weeks of culture, which were subsequently passaged and propagated. This cell line has been phenotypically and genotypically characterized using karyotyping, gene expression analysis, immunocytochemistry and florescent insitu hybridization (FISH).
Results:Cell line has a human karyotype with multiploidy and population doubling time of 60 hours. Gene expression profiling revealed negative expression of ER, PR and positive expression of androgen receptor (AR) and HER-2/neu. FISH analysis was negative for HER-2/neu amplification. Both basal (cytokeratins 5, 14 & 19) and luminal markers (cytokeratin 8 & 18) are expressed at mRNA level along with myoepithelial markers (CD10, S100A7, p-cadherin, desmin, S100A4, S100A2 & α-SMA). In accordance with mesenchymal phenotype, it has low expression of e-cadherin and high expression of vimentin. Invasion assay revealed this cell line to be non-invasive forming spheroids. CAG repeat length of AR is 22 and AR has been found to be functional by luciferase reporter assay in response to treatment with dihydrotestosterone.
Conclusions:We report a novel metaplastic carcinoma cell line from a nan-caucasian female patient with functional AR. Targeting AR signaling may be a promising therapeutic target in this rare sub-type of BCa.

Publication

Cancer Research