A Novel in vitro Model for Prostate Cancer Bone Metastasis using Microfluidics

Abstract

Alexander Cui, Srinivasa Rao, Sam Olechnowicz, James Edwards, Peter Cook, Edmond Walsh, Claire Edwards

Prostate cancer (PCa) cells predominantly metastasise to bone, and once this happens the disease is incurable. Hence it is vital to understand the mechanism of bone metastasis in PCa. Several models have been established to study PCa bone metastasis in vitro, involving the co-culture of PCa cell lines with cells of the bone microenvironment such as osteoblasts, osteoclasts, bone marrow stromal cells, etc. However, these models are limited to one-to-one co-culture (i.e., PCa cells co-cultured with one other cell type), which overly simplifies the complex bone microenvironment consisting of multiple cell types.

We aimed to overcome this limitation by adapting a microfluidics platform that employs a novel mechanism to isolate sub-microliter volumes using fluid walls. By using this technology, we were able to successfully differentiate osteoblasts and adipocytes from precursor cells (2T3 and ST2 cells respectively) in nanowells, and co-cultured them with PC3 prostate cancer cells. Differentiation to osteoblasts and adipocytes was confirmed by calcein green and BODIPY live staining which could be monitored using the Incucyte imaging platform.

Following co-culture, the PCa cells were trypsinised and total RNA was extracted from them. A cDNA amplification step was successfully incorporated into the reverse transcription protocol to provide sufficient material for quantitative PCR analysis. Further, sequencing adapters were added to the cDNA to generate an RNA-sequencing library for transcriptome-wide analysis. Using this novel model, with imaging, RNA-sequencing and qPCR as read-outs, we are working on elucidating the signalling pathways that are activated by the bone microenvironment in PCa cells.