The Expression of hCG Receptor mRNA in Four Human Ovarian Cancer Cell Lines Varies Considerably under Different Experimental Conditions

Steinmeyer, Christophe; Berkholz, Alexander; Gebauer, Gerhard; Jäger, Wolfram

doi:10.1159/000070656

Cited by 9 publications

(6 citation statements)

References 48 publications

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“…Earlier it was shown by others that OVCAR-3 cells express the LH / hCG receptor [10] . However, this cell line was not known expressing the ANG2 gene.…”

Section: Results ▼mentioning

confidence: 96%

“…We therefore cloned promoter fragments of the ANG2 regulatory region into luciferase reporter constructs, transfected these constructs in the human ovarian cancer cell line OVCAR-3, and analyzed the expression ratio before and after hCG stimulation. This cell line was shown to be a target of hCG regulated LH-receptor expression levels [10] and of hCG guided reduction of tumor volume and burden in animal models [11] .…”

Section: Introduction ▼mentioning

confidence: 99%

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Regulation of the Angiopoietin-2 Gene by hCG in Ovarian Cancer Cell Line OVCAR-3

Pietrowski¹,

Wiehle²,

Sator³

et al. 2010

Horm Metab Res

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Angiogenesis is a crucial step in growing tissues including many tumors. It is regulated by pro- and antiangiogenic factors including the family of angiopoietins and their corresponding receptors. In previous work we have shown that in human ovarian cells the expression of angiopoietin 2 (ANG2) is regulated by human chorionic gonadotropin (hCG). To better understand the mechanisms of hCG-dependent regulation of the ANG2-gene we have now investigated upstream regulatory active elements of the ANG2-promoter in the ovarian carcinoma cell line OVCAR-3. We cloned several ANG2-promoter-fragments of different lengths into a luciferase reporter-gene-vector and analyzed the corresponding ANG2 expression before and after hCG stimulation. We identified regions of the ANG2-promoter between 1 048 bp and 613 bp upstream of the transcriptional start site where hCG-dependent pathways promote a significant downregulation of gene expression. By sequence analysis of this area we found several potential binding sites for transcription factors that are involved in regulation of ANG2-expression, vascular development and ovarian function. These encompass the forkhead family transcription factors FOXC2 and FOXO1 as well as the CCAAT/enhancer binding protein family (C/EBP). In conclusion, we have demonstrated that the regulation of ANG2-expression in ovarian cancer cells is hCG-dependent and we suggest that forkhead transcription factor and C/EBP-dependent pathways are involved in the regulation of ANG2-expression in ovarian cancer cells.

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“…Earlier it was shown by others that OVCAR-3 cells express the LH / hCG receptor [10] . However, this cell line was not known expressing the ANG2 gene.…”

Section: Results ▼mentioning

confidence: 96%

Section: Introduction ▼mentioning

confidence: 99%

Regulation of the Angiopoietin-2 Gene by hCG in Ovarian Cancer Cell Line OVCAR-3

Pietrowski¹,

Wiehle²,

Sator³

et al. 2010

Horm Metab Res

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“…In particular, alternative splicing appears to be associated with cycle-dependent regulation of LHR mRNA levels in human endometrium [21] and receptor down-regulation in rat corpora lutea [17]. In addition, the different types of splice variants have also been shown to take place in pathophysiological conditions, such as endometrial carcinomas, which is related to increased levels of spliced LHR transcripts [22] or in human ovarian [31,36] and breast epithelial cell tumors [15], in which alternative splicing is shown to be altered or ceased when compared to normal cells.…”

Section: Discussionmentioning

confidence: 99%

LH receptor gene expression in cumulus cells in women entering an ART program

Papamentzelopoulou

Mavrogianni

Partsinevelos

et al. 2012

J Assist Reprod Genet

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Purpose Luteinizing hormone (LH) exerts its actions through its receptor (LHR), which is mainly expressed in theca cells and to a lesser extent in oocytes, granulosa and cumulus cells. The aim of the present study was the investigation of a possible correlation between LHR gene and LHR splice variants expression in cumulus cells and ovarian response as well as ART outcome. Methods Forty patients undergoing ICSI treatment for male factor infertility underwent a long luteal GnRH-agonist downregulation protocol with a fixed 5-day rLH pretreatment prior to rFSH stimulation and samples of cumulus cells were collected on the day of egg collection. RNA extraction and cDNA preparation was followed by LHR gene expression investigation through real-time PCR. Furthermore, cumulus cells were investigated for the detection of LHR splice variants using reverse transcription PCR. Results Concerning LHR expression in cumulus cells, a statistically significant negative association was observed with the duration of ovarian stimulation (odds ratio00.23, p00.012). Interestingly, 6 over 7 women who fell pregnant expressed at least two specific types of LHR splice variants (735 bp, 621 bp), while only 1 out of 19 women that did not express any splice variant achieved a pregnancy. Conclusions Consequently, the present study provide a step towards a new role of LHR gene expression profiling as a biomarker in the prediction of ovarian response at least in terms of duration of stimulation and also a tentative role of LHR splice variants expression in the prediction of pregnancy success.

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“…Whether such a regulatory role could be assigned to other splice variants of the LHR in general is not known. However, this is a very likely possibility, because changes in physiological stimuli (Lakkakorpi et al, 1993;Licht et al, 2003), cellular differentiation (Sokka et al, 1992;Tena-Sempere et al, 1994;Zhang et al, 1994;Apaja et al, 2004Apaja et al, , 2005 and tumorigenic cell growth (Lin et al, 1994;Reinholz et al, 2000;Jiang et al, 2002;Steinmeyer et al, 2003) have all been shown to regulate the splicing pattern of the receptor.…”

Section: Discussionmentioning

confidence: 99%

Luteinizing Hormone Receptor Ectodomain Splice Variant Misroutes the Full-Length Receptor into a Subcompartment of the Endoplasmic Reticulum

Apaja

Tuusa

Pietilä

et al. 2006

MBoC

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The luteinizing hormone receptor (LHR) is a G protein-coupled receptor that is expressed in multiple RNA messenger forms. The common rat ectodomain splice variant is expressed concomitantly with the full-length LHR in tissues and is a truncated transcript corresponding to the partial ectodomain with a unique C-terminal end. Here we demonstrate that the variant alters the behavior of the full-length receptor by misrouting it away from the normal secretory pathway in human embryonic kidney 293 cells. The variant was expressed as two soluble forms of M r 52,000 and M r 54,000, but although the protein contains a cleavable signal sequence, no secretion to the medium was observed. Only a very small fraction of the protein was able to gain hormone-binding ability, suggesting that it is retained in the endoplasmic reticulum (ER) by its quality control due to misfolding. This was supported by the finding that the variant was found to interact with calnexin and calreticulin and accumulated together with these ER chaperones in a specialized juxtanuclear subcompartment of the ER. Only proteasomal blockade with lactacystin led to accumulation of the variant in the cytosol. Importantly, coexpression of the variant with the full-length LHR resulted in reduction in the number of receptors that were capable of hormone binding and were expressed at the cell surface and in targeting of immature receptors to the juxtanuclear ER subcompartment. Thus, the variant mediated misrouting of the newly synthesized full-length LHRs may provide a way to regulate the number of cell surface receptors. INTRODUCTIONNewly synthesized proteins destined for the secretory pathway enter the endoplasmic reticulum (ER) and after correct folding and assembly are either secreted from the cell or transported to their site of action in other cellular compartments. Folding of the nascent proteins is constantly monitored by the ER quality control apparatus. It has an important task in maintaining the cellular homeostasis by preventing premature export of incompletely folded and assembled proteins and removing misfolded and unassembled ones via the ER-associated degradation (ERAD) pathway, presumably by recognizing structural signals that are enriched in incompletely folded proteins (Ellgaard and Helenius, 2003;Helenius and Aebi, 2004). Recent evidence suggests that the ER quality control does not only target permanently misfolded proteins to ERAD but may also dispose some folding competent ones, possibly due to their slow folding kinetics. This applies also to several polytopic membrane proteins, including G protein-coupled receptors (GPCRs; Petäjä-Repo et al., 2000;Imai et al., 2001;Lu et al., 2003;Wü ller et al., 2004;Pietilä et al., 2005). Thus, export from the ER is the limiting step in their expression and probably provides a mean to regulate the number of functional receptors at the cell surface. This is supported by our recent finding that final maturation of the rat luteinizing hormone receptor (rLHR) was found to be developmentally regulated in targ...

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The Expression of hCG Receptor mRNA in Four Human Ovarian Cancer Cell Lines Varies Considerably under Different Experimental Conditions

Cited by 9 publications

References 48 publications

Regulation of the Angiopoietin-2 Gene by hCG in Ovarian Cancer Cell Line OVCAR-3

Regulation of the Angiopoietin-2 Gene by hCG in Ovarian Cancer Cell Line OVCAR-3

LH receptor gene expression in cumulus cells in women entering an ART program

Luteinizing Hormone Receptor Ectodomain Splice Variant Misroutes the Full-Length Receptor into a Subcompartment of the Endoplasmic Reticulum

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