title: Estrogen receptors β1 and β2 have opposing roles in regulating proliferation and bone metastasis genes in the prostate cancer cell line PC3.
abstract: The estrogen receptor (ER)β1 is successively lost during cancer progression, whereas its splice variant, ERβ2, is expressed in advanced prostate cancer. The latter form of cancer often metastasizes to bone, and we wanted to investigate whether the loss of ERβ1 and/or the expression of ERβ2 affect such signaling pathways in prostate cancer. Using PC3 and 22Rv1 prostate cancer cell lines that stably express ERβ1 or ERβ2, we found that the ERβ variants differentially regulate genes known to affect tumor behavior. We found that ERβ1 repressed the expression of the bone metastasis regulator Runx2 in PC3 cells. By contrast, RUNX2 expression was up-regulated at the mRNA level by ERβ2 in PC3 cells, whereas Slug was up-regulated by ERβ2 in both PC3 and 22Rv1 cells. In addition, the expression of Twist1, a factor whose expression strongly correlates with high Gleason grade prostate carcinoma, was increased by ERβ2. In agreement with the increased Twist1 expression, we found increased expression of Dickkopf homolog 1; Dickkopf homolog 1 is a factor that has been shown to increase the RANK ligand/osteoprotegerin ratio and enhance osteoclastogenesis, indicating that the expression of ERβ2 can cause osteolytic cancer. Furthermore, we found that only ERβ1 inhibited proliferation, whereas ERβ2 increased proliferation. The expression of the proliferation markers Cyclin E, c-Myc, and p45(Skp2) was differentially affected by ERβ1 and ERβ2 expression. In addition, nuclear β-catenin protein and its mRNA levels were reduced by ERβ1 expression. In conclusion, we found that ERβ1 inhibited proliferation and factors known to be involved in bone metastasis, whereas ERβ2 increased proliferation and up-regulated factors involved in bone metastasis. Thus, in prostate cancer cells, ERβ2 has oncogenic abilities that are in strong contrast to the tumor-suppressing effects of ERβ1.
authors.affiliation: Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, Texas 77204-5056, USA.
authors.forename: Prasenjit
authors.initials: P
authors.lastname: Dey
authors.forename: Philip
authors.initials: P
authors.lastname: Jonsson
authors.forename: Johan
authors.initials: J
authors.lastname: Hartman
authors.forename: Cecilia
authors.initials: C
authors.lastname: Williams
authors.forename: Anders
authors.initials: A
authors.lastname: Ström
authors.forename: Jan-Åke
authors.initials: JÅ
authors.lastname: Gustafsson
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism / Q000556:secondary*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis / Q000235:genetics*; D009687:Nuclear Proteins / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism; D053244:Osteoprotegerin / Q000096:biosynthesis; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D053245:RANK Ligand / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D015398:Signal Transduction / Q000235:genetics; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation; D051879:Twist-Related Protein 1 / Q000378:metabolism
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C501126:DKK1 protein, human; D047629:Estrogen Receptor beta; D036341:Intercellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D053244:Osteoprotegerin; D020033:Protein Isoforms; D053245:RANK Ligand; D012333:RNA, Messenger; C493709:RUNX2 protein, human; C000604407:SNAI1 protein, human; C000604449:Snai2 protein, mouse; D000071250:Snail Family Transcription Factors; C103173:TWIST1 protein, human; D014157:Transcription Factors; D051879:Twist-Related Protein 1