Detection of estrogen receptor alpha and assessment of fulvestrant activity in MCF-7 tumour spheroids using microfluidics and SERS

Kapara, Anastasia and Findlay Paterson, Karla A. and Brunton, Valerie G. and Graham, Duncan and Zagnoni, Michele and Faulds, Karen (2021) Detection of estrogen receptor alpha and assessment of fulvestrant activity in MCF-7 tumour spheroids using microfluidics and SERS. Analytical Chemistry. ISSN 0003-2700

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    Breast cancer is one of the leading causes of cancer death in women. Novel in vitro tools that integrate three-dimensional (3D) tumour models with highly sensitive chemical reporters can provide useful information to aid biological characterisation of cancer phenotype and understanding of drug activity. The combination of surface enhanced Raman scattering (SERS) techniques with microfluidic technologies offers new opportunities for highly selective, specific and multiplexed nanoparticle-based assays. Here, we explored the use of functionalised nanoparticles for the detection of estrogen receptor alpha (ERα) expression in a 3D tumour model, using the ERα positive human breast cancer cell line MCF-7. This approach was used to compare targeted versus non-targeted nanoparticle interactions with the tumour model to better understand whether targeted nanotags are required to efficiently target ERα. A mixture of targeted anti-ERα antibody-functionalised nanotags (ERα-AuNPs) and non-targeted (against ERα) anti-human epidermal growth factor receptor 2 (HER2) antibody-functionalised nanotags (HER2-AuNPs), with different Raman reporters with a similar SERS signal intensity, were incubated with MCF-7 spheroids in microfluidic devices and spectroscopically analysed using SERS. MCF-7 cells express high levels of ERα and no detectable levels of HER2. 2D and 3D SERS measurements confirmed the strong targeting effect of ERα-AuNP nanotags to the MCF-7 spheroids in contrast to HER2-AuNPs (63% signal reduction). Moreover, 3D SERS measurements confirmed the differentiation between the targeted and the non-targeted nanotags. Finally, we demonstrated how the nanotag uptake on MCF-7 spheroids was affected by the drug fulvestrant, the first-in-class approved selective estrogen receptor degrader (SERD). These results illustrate the potential of using SERS and micro-fluidics as a powerful in vitro platform for the characterisation of 3D tumour models and the investigation of SERD activity.

    ORCID iDs

    Kapara, Anastasia, Findlay Paterson, Karla A., Brunton, Valerie G., Graham, Duncan ORCID logoORCID:, Zagnoni, Michele ORCID logoORCID: and Faulds, Karen ORCID logoORCID:;