OESTROGENS AND PROLACTIN REGULATE MAMMARY GLAND EPITHELIAL CELL GROWTH BY MODULATION OF THE WNT SIGNAL PATHWAY
Estrogen and prolactin can regulate mammary gland development and epithelial cell growth as well as lactation. Meanwhile, the Wnt signaling pathway and subsequent upregulation of b-catenin driven by downstream target of cyclinD1 also play a role in development of mammary gland. This study aimed to assess the possible involvement of estrogen and prolactin in regulation of cell growth in mammary gland. Bovine mammary gland epithelial cells (MECs) were treated with estrogen and prolactin (5 µg mL-1) respectively for 48 h and then measured for cell viability. mRNA and protein expression level of genes (E-cadherin, CyclinD1 and b-catenin) related with Wnt pathway were measured by qRT-PCR and Western blot respectively while sub-cellular localizations of the proteins in MECs were further monitored by immunoﬂuorescence. Expression of E-cadherin and CyclinD1 were most highly expressed at 36 h (P<0.05) whereas b-catenin was most lowly expressed at 36 h after treatment with estrogen and prolactin, respectively. Protein level of the E-cadherin and cyclinD1, which are the targets of Wnt signal pathway, were unregulated. b-catenin protein level was decreased in both hormone groups. In conclusion, prolactin and estrogen could efficiently affect cell growth of MECs and increase the expression of E-cadherin and cyclinD1 at both mRNA and protein level. Immunoﬂuorescence suggested that prolactin and estrogen impact the nuclear expression of b-catenin protein. Our current study indicated that the proliferative efﬁcacy of prolactin and estrogen on MECs was modulated through Wnt signaling pathway.
Watson CJ, Khaled WT. Mammary development in the embryo and adult: a journey of morphogenesis and commitment. Dev 2008; 135(6):995-1003.
Kass L, Erler JT, Dembo M, Weaver VM. Mammary epithelial cell: influence of extracellular matrix composition and organization during development and tumorigenesis. Int J Biochem Cell Biol 2007; 39(11):1987-1994.
Vinyoles M, Del Valle-PÃ©rez B, Curto J, et al. Multivesicular GSK3 sequestration upon Wnt signaling is controlled by p120-catenin/cadherin interaction with LRP5/6. Mol Cell 2014; 3: 444-457.
Chedly HB, Boutinaud M, Bernier-Dodier P, Marnet P-G, Lacasse P. Disruption of cell junctions induces apoptosis and reduces synthetic activity in lactating goat mammary gland. J Dairy Sci 2010; 93(7):2938-2951.
MacDonald BT, Tamai K, He X. Wnt/Î²-catenin signaling: components, mechanisms, and diseases. Dev Cell 2009; 17(1):9-26
Raymond K, Faraldo MM, Deugnier M-A, Glukhova MA. Integrins in mammary development. Semin Cell Dev Biol 2012; 5: 599-605.
Van Roy F, Berx G. The cell-cell adhesion molecule E-cadherin. Cell Mol Life Sci 2008; 65 (23):3756-3788.
Kazem A, El Sayed K, El Kerm Y. Prognostic significance of COX-2 and Î²-Catenin in colorectal carcinoma. Alexandria Med J 2014; 50(3):211-220.
Varelas X, Samavarchi-Tehrani P, Narimatsu M, et al. The Crumbs complex couples cell density sensing to Hippo-dependent control of the TGF-Î²-SMAD pathway. Dev Cell 2010;19(6):831-844.
KÃ¼hl SJ, KÃ¼hl M. On the role of Wnt/Î²-catenin signaling in stem cells. Acta Biochim Biophys 2013; 1830(2):2297-2306.
Prasad CP, Rath G, Mathur S, Bhatnagar D, Ralhan R. Potent growth suppressive activity of curcumin in human breast cancer cells: Modulation of Wnt/Î²-catenin signaling. Chem Biol Interact 2009; 181(2):263-271.
Chu EY, Hens J, Andl T, Kairo A, et al. Canonical WNT signaling promotes mammary placode development and is essential for initiation of mammary gland morphogenesis. Dev 2004;131(19):4819-4829.
Benhaj K, Akcali KC, Ozturk M. Redundant expression of canonical Wnt ligands in human breast cancer cell lines. Oncol Rep2006; 15(3):701-707.
Nguyen N, Zhu Y. Prolactin functions as a survival factor during zebrafish embryogenesis. Comp Biochem Physiol A Mol Integr Physiol 2009; 153(1):88-93.
Stingl J. Estrogen and progesterone in normal mammary gland development and in cancer. Horm Cancer 2011; 2(2):85-90.
Bocchinfuso WP, Korach KS. Mammary gland development and tumorigenesis in estrogen receptor knockout mice. J Mammary Gland Biol Neoplasia 1997; 2(4):323-334.
Alshenawy HA, El MAE-HA, Ali A. Differential caveolin-1 expression in colon carcinoma and its relation to E-cadherinâ€“Î²-catenin complex. Ann Diagn Pathol 2013; 17(6):476-482.
Nilsson J, Bjursell G, Kannius-Janson M. Nuclear Jak2 and transcription factor NF1-C2: a novel mechanism of prolactin signaling in mammary epithelial cells. Mol Cell Biol 2006; 26(15):5663-5674.
Hakim SG, Kosmehl H, Sieg P, et al. Altered expression of cellâ€“cell adhesion molecules Î²-catenin/E-cadherin and related Wnt-signaling pathway in sporadic and syndromal keratocystic odontogenic tumors. Clin Oral investig 2011;15(3):321-328.
Xu L, Jiang Y, Zheng J, et al. Aberrant expression of Î²-catenin and E-cadherin is correlated with poor prognosis of nasopharyngeal cancer. Hum Pathol 2013; 44(7):1357-1364.
Meier-Abt F, Bentires-Alj M. How pregnancy at early age protects against breast cancer. Trends Mol Med 2014; 20(3):143-153.
WAN Z-y, TONG H-l, LI Q-z, GAO X-j. Influence on cellular signal transduction pathway in dairy cow mammary gland epithelial cells by galactopoietic compound isolated from Vaccariae segetalis. Agric Sci China 2011; 10(4):619-630.
Feuermann Y, Mabjeesh SJ, Shamay A. Mammary fat can adjust prolactin effect on mammary epithelial cells via leptin and estrogen. Int J Endocrinol 2009; 2009:8.
Tworoger SS, Hankinson SE. Prolactin and breast cancer risk. Cancer lett (2006); 243(2):160-169.
Resnitzky D, Gossen M, Bujard H, Reed S. Acceleration of the G1/S phase transition by expression of cyclins D1 and E with an inducible system. Mol Cell Biol 1994; 14(3):1669-1679.
Laezza C, Dâ€™Alessandro A, Paladino S, et al. Anandamide inhibits the Wnt/Î²-catenin signalling pathway in human breast cancer MDA MB 231 cells. Eur J Cancer 2012; 48(16):3112-3122.
Mastroianni M, Kim S, Kim YC, Esch A, Wagner C, Alexander CM. Wnt signaling can substitute for estrogen to induce division of ERÎ±-positive cells in a mouse mammary tumor model. Cancer lett 2010; 289 (1):23-31.
Mawson A, Lai A, Carroll JS, Sergio CM, Mitchell CJ, Sarcevic B. Estrogen and insulin/IGF-1 cooperatively stimulate cell cycle progression in MCF-7 breast cancer cells through differential regulation of c-Myc and cyclin D1. Mol Cell Endocrinol 2005; 229(1):161-173.
Su Y, Simmen RC Soy isoflavone genistein upregulates epithelial adhesion molecule E-cadherin expression and attenuates Î²-catenin signaling in mammary epithelial cells. Carcinogenesis 2009; 30(2):331-339.
Koehler A, Schlupf J, Schneider M, Kraft B, Winter C, Kashef J. Loss of Xenopus cadherin-11 leads to increased Wnt/Î²-catenin signaling and up-regulation of target genes c-myc and cyclin D1 in neural crest. Dev Biol 2013; 383 (1):132-145.