Dataset Information

A novel approach for the discovery of biomarkers of radiotherapy response in breast cancer

ABSTRACT: Radiotherapy is a commonly used treatment modality for the local control of breast cancer. However, the clinical signs of radiotherapy response are often not apparent for several weeks post-treatment. We currently lack tools to predict and/or monitor tumor responses during treatment. The aim of this study was to identify tumor secreted biomarkers of radiotherapy response. Estrogen receptor positive (ER+) MCF-7 cells were serum-starved for 2 h, and were then exposed to various doses of radiation (0, 2, 4, 6, 8 or 10 Gy). Conditioned media (CM) was harvested at 1, 2, 4, 8 and 24 h post-radiation for each radiation dose. Samples underwent processing for liquid chromatography-mass spectrometry (LC-MS) following collection. 33 proteins at the 24 h time point were found to have significantly increased secretion levels (up to 12-fold) at all radiation doses compared to untreated cells. To validate the secretomic results and to further investigate the potential use of these proteins as biomarkers of radiosensitivity, the secreted protein levels of candidate biomarkers were assessed through western blot (WB). WB analysis was performed using CM samples to assess the secretion levels from parental and radioresistant (RR) cell lines (developed within our lab) 24 h after the cells had received a single radiation dose of 2 Gy. Secretion levels of our candidate biomarkers were found to be significantly increased from the radiosensitive MCF-7 cells treated with 2 Gy of radiation at 24 h compared to 24 h untreated controls. In comparison, candidate biomarker levels in the CM samples from untreated and radiation-treated MCF-7 RR cells remained low. Currently there are no validated predictive biomarkers to monitor radiotherapy responses during treatment. These biomarkers could have a clinical role in personalising radiotherapy dosing schedules and durations for solid tumours in the neoadjuvant and palliative setting.

INSTRUMENT(S): Q Exactive Plus

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

DISEASE(S): Breast Cancer

SUBMITTER: Jimi Wills

LAB HEAD: Arran Turnbull

PROVIDER: PXD027572 | Pride | 2021-08-13

REPOSITORIES: Pride

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Publications

Tissue- and Liquid-Based Biomarkers in Prostate Cancer Precision Medicine.

Meehan James J Gray Mark M Martínez-Pérez Carlos C Kay Charlene C McLaren Duncan D Turnbull Arran K AK

Journal of personalized medicine 20210715 7

Worldwide, prostate cancer (PC) is the second-most-frequently diagnosed male cancer and the fifth-most-common cause of all cancer-related deaths. Suspicion of PC in a patient is largely based upon clinical signs and the use of prostate-specific antigen (PSA) levels. Although PSA levels have been criticised for a lack of specificity, leading to PC over-diagnosis, it is still the most commonly used biomarker in PC management. Unfortunately, PC is extremely heterogeneous, and it can be difficult to ...[more]

PMID: 34357131

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Project description:Background: Radiotherapy plays an important role in the multimodal treatment of breast cancer. The response of a breast tumour to radiation depends not only on its innate radiosensitivity but also on tumour repopulation by cells that have developed radioresistance. Development of effective cancer treatments will require further molecular dissection of the processes that contribute to resistance. Methods: Radioresistant cell lines were established by exposing MDA-MB-231, MCF-7 and ZR-751 parental cells to increasing weekly doses of radiation. The development of radioresistance was evaluated through proliferation and colony formation assays. Phenotypic characterisation included migration and invasion assays and immunohistochemistry. Intrinsic differences and changes in response to radiation between parental and radioresistant cells were investigated by whole-transcriptome gene expression analysis. Gene enrichment and pathway-focused analyses identified signalling networks differentially activated in radioresistant cells, which were confirmed by western blotting. Results: Proliferation and colony formation assays confirmed radioresistance. Radioresistant cells exhibited enhanced migration and invasion, with evidence of epithelial-to-mesenchymal-transition, and limited activation of DNA damage and apoptotic pathways in response to 2 Gy ionising radiation. Significantly, acquisition of radioresistance in MCF-7 and ZR-751 cell lines resulted in a loss of expression of both ERα and PgR and an increase in EGFR expression; based on gene analysis they changed subtype classification from their parental luminal A to HER2-overexpressing (MCF-7 RR) and normal-like (ZR-751 RR) subtypes, indicating the extent of phenotypic changes and cellular plasticity involved in this process. Whole-transcriptome gene expression analysis identified down-regulation of ER signalling genes and up-regulation of genes associated with PI3K, MAPK and WNT pathway activity in radioresistant cell lines derived from ER+ cells; this was confirmed by western blot, which showed increased p-AKT and p-ERK expression following radiation. Conclusions: This is the first study to date that extensively describes the development and characterisation of three novel radioresistant breast cancer cell lines through both genetic and phenotypic analysis. More changes were identified between parental cells and their radioresistant derivatives in the ER+ (MCF-7 and ZR-751) compared with the ER- cell line (MDA-MB-231) model; however, multiple and likely interrelated mechanisms were identified that may contribute to the development of acquired resistance to radiotherapy.

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	MCF7_1h_0Gy.raw	Raw
	MCF7_1h_10Gy.raw	Raw
	MCF7_1h_2Gy.raw	Raw
	MCF7_1h_4Gy.raw	Raw
	MCF7_1h_6Gy.raw	Raw