Role of HDL and Scavenger Receptor Class B Type I (SR-BI) Expression in LNCaP and PC-3 Prostate Cancer Cell Lines. Growth Patterns in the Chick Chorioallantoic Membrane Model

Abstract

Cholesterol metabolism is a key pathway affecting androgen synthesis and prostate cancer cell proliferation. Major receptors and transporters involved in cellular cholesterol homeostasis and cholesterol fluxes are ATP-binding cassette protein A1 (ABCA1), LDL receptor (LDLR) and the HDL receptor scavenger receptor class B type I (SR-BI). Especially SR-BI deserves more and more attention because it has been shown to be overexpressed by the majority of malignant tumours, promoting their proliferation and metastasis. PC-3 and LNCaP are two of the commonly used cell lines for in vitro prostate cancer studies. A comparative overview of the expression of receptors involved in cholesterol uptake and their activities in these two cell lines was missing; therefore we reviewed the current knowledge on this topic. We investigated the expression of SR-BI in these two cell lines and the uptake of labelled HDL. In order to study and compare tumour development, we assessed the growth of both cell lines in the chick chorioallantoic membrane (CAM) model. Although microtumours successfully developed, size increase was limited as confirmed by the analysis of the proliferation marker Ki67. Interestingly prostate-specific antigen (PSA) secreted by LNCaP tumours could be determined in the chick embryo blood. SR-BI is a promising therapeutic target either by its direct inhibition or more importantly as an agent for drug delivery.