Human ex vivo 3D bone model recapitulates osteocyte response to metastatic prostate cancer

Jenny Zilberberg,Woo Lee,Lucas Tricoli,Christopher Albanese,Saba Choudhary,Yair Kissin,Eugenia Dziopa,Ciaran Mannion,Poornema Ramasundaram

doi:10.1038/s41598-018-36424-x

Abstract

Prostate cancer (PCa) is the second leading cause of cancer deaths among American men. Unfortunately, there is no cure once the tumor is established within the bone niche. Although osteocytes are master regulators of bone homeostasis and remodeling, their role in supporting PCa metastases remains poorly defined. This is largely due to a lack of suitable ex vivo models capable of recapitulating the physiological behavior of primary osteocytes. To address this need, we integrated an engineered bone tissue model formed by 3D-networked primary human osteocytes, with conditionally reprogrammed (CR) primary human PCa cells. CR PCa cells induced a significant increase in the expression of fibroblast growth factor 23 (FGF23) by osteocytes. The expression of the Wnt inhibitors sclerostin and dickkopf-1 (Dkk-1), exhibited contrasting trends, where sclerostin decreased while Dkk-1 increased. Furthermore, alkaline phosphatase (ALP) was induced with a concomitant increase in mineralization, consistent with the predominantly osteoblastic PCa-bone metastasis niche seen in patients. Lastly, we confirmed that traditional 2D culture failed to reproduce these key responses, making the use of our ex vivo engineered human 3D bone tissue an ideal platform for modeling PCa-bone interactions.

Highlights

Prostate cancer (PCa) is the second leading cause of cancer deaths among American men[1,2]
This single cell layer primarily comprised of osteoblasts and localized at the interface between the bone marrow and bone, is critical in bone metastasis since it represent the site where disseminated tumor cells interact with the bone and become dormant and drug resistance until tumor reactivation and progression[39]
We investigated the osteoblastic nature of PCa bone metastasis by examining the expression of alkaline phosphatase (ALP), an indication of bone-forming osteoblastic activity

Summary

Introduction

Prostate cancer (PCa) is the second leading cause of cancer deaths among American men[1,2]. We established that hypoxic 3D culture of human primary osteocytic cells enhanced osteocyte phenotype ex vivo while enabling the spontaneous formation of an osteoblastic monolayer that resembles the endosteal layer[38]. This single cell layer primarily comprised of osteoblasts and localized at the interface between the bone marrow and bone, is critical in bone metastasis since it represent the site where disseminated tumor cells interact with the bone and become dormant and drug resistance until tumor reactivation and progression[39]

Methods

Results

Conclusion