Trophoblast‐like human choriocarcinoma cells serve as a suitable in vitro model for selective cholesteryl ester uptake from high density lipoproteins

Abstract

As human choriocarcinoma cells display many of the biochemical and morphological characteristics reported for in utero invasive trophoblast cells we have studied cholesterol supply from high density lipoproteins (HDL) to these cells. Binding properties of 125I‐labeled HDL subclass 3 (HDL3) at 4 °C were similar for BeWo, JAr, and Jeg3 choriocarcinoma cell lines while degradation rates at 37 °C were highest for BeWo. Calculating the selective cholesteryl ester (CE)‐uptake as the difference between specific cell association of [3H]CE‐labeled HDL3 and holoparticle association of 125I‐labeled HDL3 revealed that in BeWo cells, the selective CE‐uptake was slightly lower than holoparticle association. However, the pronounced capacity for specific cell association of [3H]CE‐HDL3 and selective [3H]CE‐uptake in excess of HDL3–holoparticle association, and cAMP–mediated enhanced cell association of [3H]CE‐HDL3 in JAr and Jeg3 suggested the scavenger receptor class B, type I (SR‐BI) to be responsible for this pathway. Abundant expression of SR‐BI (but not SR‐BII, a splice variant of SR‐BI) could be observed in JAr and Jeg3 but not in BeWo cells using RT‐PCR, Northern and Western blot analysis, and immunocytochemical technique. Adenovirus‐mediated overexpression of SR‐BI in all three choriocarcinoma cell lines resulted in an enhanced capacity for cell association of [3H]CE‐HDL3 (20‐fold in BeWo; fivefold in JAr and Jeg3). The fact that exogenous HDL3 remarkably increases proliferation in JAr and Jeg3 supports the notion that selective CE‐uptake and subsequent intracellular generation of cholesterol is coupled to cellular growth. From our findings we propose that JAr and Jeg3 cells serve as a suitable in vitro model to study selective CE‐supply to human placental cells.

Transport of cholesterol across a BeWo cell monolayer

“…In addition, BeWo cells express the LDL receptor and SR-BI, as do placental cells (75,76). However, these data are not in agreement with a recent study suggesting that BeWo cells do not express SR-BI (57). The discrepancy between studies could be due to the b30 subclone of BeWo cells or to the specificity of the different antibodies used for protein detection in the two studies.…”

“…1A) (57). The presence of a larger protein was expected, because previous studies have demonstrated that human SR-BI from villous trophoblast migrates with a molecular mass slightly higher than that of rodent SR-BI (55), and the human protein sequence is 43 amino acids longer than that of the mouse.…”

HOXC10 is overexpressed in breast cancer and transcriptionally regulated by estrogen via involvement of histone methylases MLL3 and MLL4

“…Similarly, JAR cell is a placental choriocarcinoma cell line and placenta is known to produce various steroid hormones that are circulated to fetus as well as to the mother (Strauss et al 1996). JAR cells are ER-positive cell line and have been previously used for steroid hormone-related studies (Wadsack et al 2003). Thus, overexpression of HOXC10 in breast carcinoma tissue and also in JAR, MCF7, and T47D cell lines indicated that HOXC10 is potentially regulated by estrogen.…”

In Vitro Models Using the Human Placenta to Study Fetal Exposure to Drugs

“…Since cells from human choriocarcinoma display many of the biochemical and morphological characteristics reported for in utero invasive trophoblast cells (Wadsack et al 2003), these cell lines are more commonly used as a model that mimics the placental barrier. Utoguchi et al (2000) have been able to show that, in BeWo monolayers, the basolateral to apical transport of known p-glycoprotein substrates, vinblastin, vincristine and digoxin, is signifi cantly greater than transport to opposite direction.…”