Establishing the Effects of Adipose Derived Stem Cells (ADSCs) on the Tumorigenic Characteristics of Breast Cancer
Authors:   , Thomson Emman 
Published: January 2023

Introduction: Breast Cancer affects approximately 55,000 women in the UK every year, with the majority (>70%) being oestrogen receptor (ER) positive. Advancements in screening, imaging and adjuvant therapies mean more women are diagnosed earlier and undergo breast-conserving surgery (BCS). There has been a resultant rise in the use of free fat transfer (FFT) to reconstruct the small to medium volume loss, utilising autologous adipose tissue. Contemporary scientific studies demonstrate that co-location of breast cancer and adipose derived stem cells (ADSCs) present in FFT, results in the conference of a malignant advantage via cytokine release and co-located cell-to-cell interaction. As these studies predominantly utilise ADSCs isolated from healthy patients, there is a limit to how these results apply to the clinical patient group of women with breast cancer. This thesis aimed to create, for the first time, a clinically representative model by isolating ADSCs from women with breast cancer undergoing systemic treatment. Thus establishing if patient selection plays a role in the effects imparted by ADSCs upon the functional and phenotypic characteristics associated with the cancer hallmarks. Methods: An optimised ADSC isolation protocol produced a reliable cell population for the study duration. ADSCs harvested from patients with (n=10) and without breast cancer (n=6) were isolated and fully characterised using the Dominici criteria for stem cells. Conditioned media (CM) and non-contact co-culture models were applied to examine the effect that ADSCs isolated from breast cancer patients had on the neoplastic traits of MCF-7 and T47D ER+ breast cancer cell lines when compared with their healthy counterparts. Experiments were designed to measure a range of functional and morphological endpoints, related to the cancer hallmarks. This included proliferation, changes in cellular adhesion and migration, invasion, cellular and nuclei morphology, protein expression and bioenergetics. Results: Successfully isolated ADSCs demonstrated plastic adherence, trilineage differentiation and appropriate cell surface markers as confirmed using flow cytometry. Data showed statistically significant increases (p<0.05) in proliferation and invasion only when MCF-7 cells were treated with media conditioned by ADSCs from healthy patients. Significant increases in migration and invasion, with reduction in adhesion and raised concentrations of cytokines (IL-6, VEG-F and MCP-1) was only seen when MCF-7 cells were co-cultured with ADSCs isolated from healthy patients. There was a lack of effect seen in both CM and co-culture experiments involving ADSCs isolated from cancer patients, a novel finding, as this patient group had not previously been a focus of study. Similar results were seen in the second ER+ cell line (T47D) which was used for experimental validation, with increases in proliferation, invasion, and an increase in abnormal metabolic activity when co-cultured with healthy ADSCs only. Conclusion: Utilising a novel approach to patient selection, it has been possible to show a divergence in the behaviour of ADSCs isolated from patients with breast cancer undergoing systemic treatment, when compared with ADSCs isolated from healthy patients. This study presents a two-part cell-based model which more accurately represents the clinical population undergoing FFT. This study recommends an alternative patient group (women with cancer on systemic treatment) as the primary cell source for research examining ADSC behaviour in the breast cancer micro-environment.