title: Silencing of the icb-1 gene inhibits the induction of differentiation-associated genes by vitamin D3 and all-trans retinoic acid in gynecological cancer cells.
abstract: Icb-1 (C1orf38) is a human gene initially described by our group to be involved in differentiation processes of cancer cells. To further elucidate the function of the icb-1 gene in differentiation of breast and endometrial cancer cells, we knocked down its expression by means of shRNA transfection. Knockdown of icb-1 inhibited the vitamin D3-induced up-regulation of E-cadherin expression in both MCF-7 and HEC-1B cells. Induction of E-cadherin expression by all-trans retinoic acid (ATRA) was also blocked in both cell lines expressing icb-1 siRNA. Examination of icb-1 and E-cadherin expression in 66 breast cancer tissue samples revealed a significant positive correlation between the two genes. In MCF-7 cells, silencing of the icb-1 gene inhibited the ATRA- and the vitamin D3-induced up-regulation of lactoferrin and estrogen receptor β expression. The data of our knockdown study suggest that icb-1 may act as a mediator of differentiation signals in breast cancer cells induced by ATRA or vitamin D3. These findings together with the observed co-expression of icb-1 with E-cadherin in breast cancer samples support an important role of the icb-1 gene in cancer cell differentiation.
authors: Department of Obstetrics and Gynecology, University Medical Center Regensburg, Regensburg, Germany.
authors: Martina
authors: M
authors: Haselberger
authors: Anette
authors: A
authors: Springwald
authors: Anna
authors: A
authors: Konwisorz
authors: Claus
authors: C
authors: Lattrich
authors: Regina
authors: R
authors: Goerse
authors: Olaf
authors: O
authors: Ortmann
authors: Oliver
authors: O
authors: Treeck
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D045744:Cell Line, Tumor; D002762:Cholecalciferol / Q000494:pharmacology; D047629:Estrogen Receptor beta / Q000235:genetics / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D005833:Genital Neoplasms, Female / Q000378:metabolism / Q000473:pathology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007781:Lactoferrin / Q000235:genetics / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D015820:Cadherins; D047629:Estrogen Receptor beta; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; C111850:THEMIS2 protein, human; D002762:Cholecalciferol; D014212:Tretinoin; D007781:Lactoferrin