Lung epithelial cells induce both phenotype alteration and senescence in breast cancer cells

Furukawa M, Wheeler S, Clark AM, Wells A
Source: PLoS ONE
Publication Date: (2015)
Issue: 10 (1): e0118060
Research Area:
Cancer Research/Cell Biology
Cells used in publication:
Epithelial, bronchial (NHBE), human
Species: human
Tissue Origin: lung
Species: human
Tissue Origin: lung
Epithelial, Small Airway, human (SAEC)
Species: human
Tissue Origin: lung
Methods Normal epithelial cells (SAEC, NHBE, and BEAS-2b) were co-cultured with breast cancer cell lines (MCF-7 and MDA-MB-231). Breast cancer outgrowth and phenotype was measured using flow cytometry, immunofluorescence staining for E-adherin or Ki-67, and beta-galactosidase assays (senescence). Results Normal lung epithelial cells co-cultured with breast cancer cells showed slowed growth kinetics and a change in phenotype.
PURPOSE: The lung is one of the most common sites of breast cancer metastasis. While metastatic seeding is often accompanied by a dormancy-promoting mesenchymal to epithelial reverting transitions (MErT), we aimed to determine whether lung epithelial cells can impart this phenotype on aggressive breast cancer cells. METHODS: Co-culture experiments of normal lung epithelial cell lines (SAEC, NHBE or BEAS-2B) and breast cancer cell lines (MCF-7 or MDA-MB-231) were conducted. Flow cytometry analysis, immunofluorescence staining for E-cadherin or Ki-67 and senescence associated beta-galactosidase assays assessed breast cancer cell outgrowth and phenotype. RESULTS: Co-culture of the breast cancer cells with the normal lung cells had different effects on the epithelial and mesenchymal carcinoma cells. The epithelial MCF-7 cells were increased in number but still clustered even if in a slightly more mesenchymal-spindle morphology. On the other hand, the mesenchymal MDA-MB-231 cells survived but did not progressively grow out in co-culture. These aggressive carcinoma cells underwent an epithelial shift as indicated by cuboidal morphology and increased E-cadherin. Disruption of E-cadherin expressed in MDA-MB-231 using shRNA prevented this phenotypic reversion in co-culture. Lung cells limited cancer cell growth kinetics as noted by both (1) some of the cells becoming larger and positive for senescence markers/negative for proliferation marker Ki-67, and (2) Ki-67 positive cells significantly decreasing in MDA-MB-231 and MCF-7 cells after co-culture. CONCLUSIONS: Our data indicate that normal lung epithelial cells can drive an epithelial phenotype and suppress the growth kinetics of breast cancer cells coincident with changing their phenotypes.