Breast cancer cells treated with proton beam: Immunological features and gene signatures

The breast cancer (BC) disease is characterized by a wide heterogeneity at both clinical and molecular level, showing distinct subtypes with different clinical outcomes. Thus, the choice of the therapeutic plan, such as the type of radiotherapy (RT) need to take into account this complexity. Indeed, the proton therapy (PT) shows a medical benefit compared to conventional X-ray RT, as regards the localized delivery of the radiation dose sparing health tissues, but few data regarding proton-induced molecular changes are currently available. The aim of this study was therefore to investigate the production of immunological molecules and gene expression profiles induced by proton irradiation on BC cell lines. Clonogenic survival assay, luminex assay and cDNA microarray gene expression analyses were performed both in the non-tumorigenic MCF10A cell line and in two tumorigenic MCF7 and MDA-MB-231 cell lines, following irradiation with 0.5, 2 and 9 Gy of clinical proton beams. We found that proton irradiation induced gene expression changes useful to define a cell line and dose-dependent gene signatures. The lack of molecular data in the literature can be filled by data here presented that could represent a useful tool to better understand the molecular mechanisms elicited by protons predicting the treatment outcome.