Conditionally Reprogrammed Cells from Patient-Derived Xenograft to Model Neuroendocrine Prostate Cancer Development.

Xinpei Ci,Xin Dong,Hui Xue,Colin C Collins,Xuefeng Liu,Yuzhuo Wang,Jun Hao,Rebecca Wu,Anne M Haegert,Stephen Yiu Chuen Choi,Dong Lin

doi:10.3390/cells9061398

Abstract

Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer. It develops mainly via NE transdifferentiation of prostate adenocarcinoma in response to androgen receptor (AR)-inhibition therapy. The study of NEPC development has been hampered by a lack of clinically relevant models. We previously established a unique and first-in-field patient-derived xenograft (PDX) model of adenocarcinoma (LTL331)-to-NEPC (LTL331R) transdifferentiation. In this study, we applied conditional reprogramming (CR) culture to establish a LTL331 PDX-derived cancer cell line named LTL331_CR_Cell. These cells retain the same genomic mutations as the LTL331 parental tumor. They can be continuously propagated in vitro and can be genetically manipulated. Androgen deprivation treatment on LTL331_CR_Cells had no effect on cell proliferation. Transcriptomic analyses comparing the LTL331_CR_Cell to its parental tumor revealed a profound downregulation of the androgen response pathway and an upregulation of stem and basal cell marker genes. The transcriptome of LTL331_CR_Cells partially resembles that of post-castrated LTL331 xenografts in mice. Notably, when grafted under the renal capsules of male NOD/SCID mice, LTL331_CR_Cells spontaneously gave rise to NEPC tumors. This is evidenced by the histological expression of the NE marker CD56 and the loss of adenocarcinoma markers such as PSA. Transcriptomic analyses of the newly developed NEPC tumors further demonstrate marked enrichment of NEPC signature genes and loss of AR signaling genes. This study provides a novel research tool derived from a unique PDX model. It allows for the investigation of mechanisms underlying NEPC development by enabling gene manipulations ex vivo and subsequent functional evaluations in vivo.

Highlights

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men worldwide, with1.3 million new cases and 360,000 deaths reported in 2018 [1]
Primary conditional reprogramming (CR) cell lines were established following protocols reported in previous studies [20,21]
The average population doubling time was 72 h as estimated from 20 passages over 200 days (Figure 1C). This doubling time is three-fold shorter than that of the parental tumor (9 days) [10]. These CR cells were amenable to genetic manipulation as demonstrated by fluorescent protein labeling using lentiviral transduction (Figure 1D)

Summary

Introduction

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men worldwide, with. 1.3 million new cases and 360,000 deaths reported in 2018 [1]. Cells 2020, 9, 1398 and more potent androgen receptor pathway inhibitors (ARPI) have brought significant improvements to the management of advanced PCa over the past decades. The study of the relevant underlying mechanisms is limited by a lack of models. Developing better models and extending the applications of existing ones are fundamental in aiding novel therapeutic development. Neuroendocrine prostate cancer (NEPC) is an extremely aggressive subtype of PCa. While de novo cases are extremely rare (0.05% of PCa) [4], its incidence reaches 17–25% of patients receiving

Methods

Results

Conclusion