Dense collagen-I matrices enhance pro-tumorigenic estrogen-prolactin crosstalk in MCF-7 and T47D breast cancer cells

PLoS ONE

Volumn 10, Issue 1, 2015, Pages

  Barcus, Craig E ^a,b   Holt, Elizabeth C ^a   Keely, Patricia J ^b,c,d   Eliceiri, Kevin W ^b,d   Schuler, Linda A ^a,b,d  

^a UNIVERSITY OF WISCONSIN MADISON   (United States)

^b UNIVERSITY OF WISCONSIN MADISON   (United States)

^c UNIVERSITY OF WISCONSIN SCHOOL OF MEDICINE AND PUBLIC HEALTH   (United States)

^d UNIVERSITY OF WISCONSIN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

COLLAGEN TYPE 1; ESTRADIOL; PROLACTIN; ESTROGEN RECEPTOR ALPHA; PROLACTIN RECEPTOR;

ARTICLE; BREAST CANCER; CANCER GROWTH; CELL CULTURE; CELL DENSITY; CONTROLLED STUDY; DOWN REGULATION; ENZYME ACTIVATION; EXTRACELLULAR MATRIX; GENETIC TRANSCRIPTION; IN VITRO STUDY; MCF 7 CELL LINE; PROTEIN FUNCTION; PROTEIN PROTEIN INTERACTION; TUMOR INVASION; TUMOR MICROENVIRONMENT; UPREGULATION; BREAST TUMOR; CELL CULTURE TECHNIQUE; CELL MOTION; CELL PROLIFERATION; DRUG EFFECTS; FEMALE; GENE EXPRESSION REGULATION; GENETICS; HUMAN; MCF-7 CELL LINE; METABOLISM; PATHOLOGY; TUMOR CELL LINE;

BREAST NEOPLASMS; CELL CULTURE TECHNIQUES; CELL LINE, TUMOR; CELL MOVEMENT; CELL PROLIFERATION; COLLAGEN TYPE I; ESTRADIOL; ESTROGEN RECEPTOR ALPHA; EXTRACELLULAR MATRIX; FEMALE; GENE EXPRESSION REGULATION, NEOPLASTIC; HUMANS; MCF-7 CELLS; PROLACTIN; RECEPTORS, PROLACTIN;

EID: 84921930412     PISSN: None     EISSN: 19326203     Source Type: Journal    
DOI: 10.1371/journal.pone.0116891     Document Type: Article

References (83)

1. Anderson WF, Katki HA, Rosenberg PS (2011) Incidence of breast cancer in the United States: current and future trends. J Natl Cancer Inst 103: 1397-1402. doi: 10.1093/jnci/djr257 PMID: 21753181
2. Glass AG, Lacey JV, Carreon JD, Hoover RN (2007) Breast cancer incidence, 1980-2006: combined roles of menopausal hormone therapy, screening mammography, and estrogen receptor status. J Natl Cancer Inst 99: 1152-1161. doi: 10.1093/jnci/djm226 PMID: 17652280
3. Voduc KD, Cheang MCU, Tyldesley S, Gelmon K, Nielsen TO, et al. (2010) Breast cancer subtypes and the risk of local and regional relapse. J Clin Oncol 28: 1684-1691. doi: 10.1200/JCO.2009.24.9284 PMID: 20194857
4. Musgrove EA, Sutherland RL (2009) Biological determinants of endocrine resistance in breast cancer. Nat Rev Cancer 9: 631-643. doi: 10.1038/nrc2713 PMID: 19701242
5. Osborne C, Schiff R (2011) Mechanisms of endocrine resistance in breast cancer. Annu Rev Med 62: 233-247. doi: 10.1146/annurev-med-070909-182917 PMID: 20887199
6. Roop RP, Ma CX (2012) Endocrine resistance in breast cancer: molecular pathways and rational development of targeted therapies. Futur Oncol 8: 273-292. doi: 10.2217/fon.12.8
7. Alowami S, Troup S, Al-Haddad S, Kirkpatrick I, Watson PH (2003) Mammographic density is related to stroma and stromal proteoglycan expression. Breast Cancer Res 5: R129-R135. doi: 10.1186/bcr622 PMID: 12927043
8. Walker RA (2001) The complexities of breast cancer desmoplasia. Breast Cancer Res 3: 143-145. doi: 10.1186/bcr287 PMID: 11305947
9. Arendt LM, Rudnick JA, Keller PJ, Kuperwasser C (2010) Stroma in breast development and disease. Semin Cell Dev Biol 21: 11-18. doi: 10.1016/j.semcdb.2009.10.003
10. Conklin MW, Eickhoff JC, Riching KM, Pehlke CA, Eliceiri KW, et al. (2011) Aligned collagen is a prognostic signature for survival in human breast carcinoma. Am J Pathol 178: 1221-1232. doi: 10.1016/j.ajpath.2010.11.076 PMID: 21356373
11. Ramaswamy S, Ross KN, Lander ES, Golub TR (2003) A molecular signature of metastasis in primary solid tumors. Nat Genet 33: 49-54. doi: 10.1038/ng1060 PMID: 12469122
12. Conklin MW, Keely PJ (2012) Why the stroma matters in breast cancer: Insights into breast cancer patient outcomes through the examination of stromal biomarkers. Cell Adh Migr 6: 249-260. doi: 10.4161/cam.20567 PMID: 22568982
13. Keely P (2011) Mechanisms by which the extracellular matrix and integrin signaling act to regulate the switch between tumor suppression and tumor promotion. J Mammary Gland Biol Neoplasia 16: 205-219. doi: 10.1007/s10911-011-9226-0 PMID: 21822945
14. Butcher D, Alliston T, Weaver V (2009) A tense situation: forcing tumour progression. Nat Rev Cancer 9: 108-122. doi: 10.1038/nrc2544 PMID: 19165226
15. Lu P, Weaver VM, Werb Z (2012) The extracellular matrix: a dynamic niche in cancer progression. J Cell Biol 196: 395-406. doi: 10.1083/jcb.201102147 PMID: 22351925
16. Provenzano PP, Inman DR, Eliceiri KW, Knittel JG, Yan L, et al. (2008) Collagen density promotes mammary tumor initiation and progression. BMC Med 6: 15. doi: 10.1186/1741-7015-6-11
17. Tworoger SS, Hankinson SE (2008) Prolactin and breast cancer etiology: An epidemiologic perspective. J Mammary Gland Biol Neoplasia 13: 41-53. doi: 10.1007/s10911-008-9063-y PMID: 18246319
18. Tworoger SS, Eliassen AH, Zhang X, Qian J, Sluss PM, et al. (2013) A 20-year prospective study of plasma prolactin as a risk marker of breast cancer development. Cancer Res 73: 4810-4819. doi: 10.1158/0008-5472.CAN-13-0665 PMID: 23783576
19. Touraine P, Martini J-F, Zafrani B, Durand J-C, Labaille F, et al. (1998) Increased expression of prolactin receptor gene assessed by quantitative polymerase chain reaction in human breast tumors versus normal breast tissues. J Clin Endocrinol Metab 83: 667-674. doi: 10.1210/jcem.83.2.4564 PMID: 9467590
20. Fiorillo AA, Medler TR, Feeney YB, Wetz SM, Tommerdahl KL, et al. (2013) The prolactin receptor transactivation domain is associated with steroid hormone receptor expression and malignant progression of breast cancer. Am J Pathol 182: 217-233. doi: 10.1016/j.ajpath.2012.09.021 PMID: 23159947
21. Sato T, Tran TH, Peck AR, Liu C, Ertel A, et al. (2013) Global profiling of prolactin-modulated transcripts in breast cancer in vivo. Mol Cancer 12: 59. doi: 10.1186/1476-4598-12-59 PMID: 23758962
22. Chen Y, Huang K, Chen KE, Walker AM (2010) Prolactin and estradiol utilize distinct mechanisms to increase serine-118 phosphorylation and decrease levels of estrogen receptor alpha in T47D breast cancer cells. Breast Cancer Res Treat 120: 369-377. doi: 10.1007/s10549-009-0400-7 PMID: 19377875
23. Rasmussen LM, Frederiksen KS, Din N, Galsgaard E, Christensen L, et al. (2010) Prolactin and oestrogen synergistically regulate gene expression and proliferation of breast cancer cells. Endocr Relat Cancer 17: 809-822. doi: 10.1677/ERC-09-0326 PMID: 20601496
24. Gutzman JH, Nikolai SE, Rugowski DE, Watters JJ, Schuler LA (2005) Prolactin and estrogen enhance the activity of activating protein 1 in breast cancer cells: role of extracellularly regulated kinase 1/2-mediated signals to c-fos. Mol Endocrinol 19: 1765-1778. doi: 10.1210/me.2004-0339 PMID: 15746191
25. Arendt LM, Grafwallner-Huseth TL, Schuler LA (2009) Prolactin-growth factor crosstalk reduces mammary estrogen responsiveness despite elevated ER alpha expression. Am J Pathol 174: 1065-1074. doi: 10.2353/ajpath.2009.080719 PMID: 19179608
26. González L, Zambrano A, Lazaro-Trueba I, Lopéz E, González JJA, et al. (2009) Activation of the unliganded estrogen receptor by prolactin in breast cancer cells. Oncogene 28: 1298-1308. doi: 10.1038/onc.2008.473 PMID: 19169277
27. Ormandy CJ, Hall RE, Manning DL, Robertson JFR, Blamey RW, et al. (1997) Coexpression and cross-regulation of the prolactin receptor and sex steroid hormone receptors in breast cancer. J Clin Endo Metabol 82: 3692-3699. doi: 10.1210/jc.82.11.3692
28. Dong J, Tsai-Morris C-H, Dufau ML (2006) A novel estradiol/estrogen receptor alpha-dependent transcriptional mechanism controls expression of the human prolactin receptor. J Biol Chem 281: 18825-18836. doi: 10.1074/jbc.M512826200 PMID: 16651265
29. Gutzman JH, Miller KK, Schuler LA (2004) Endogenous human prolactin and not exogenous human prolactin induces estrogen receptor alpha and prolactin receptor expression and increases estrogen responsiveness in breast cancer cells. J Steroid Biochem Mol Biol 88: 69-77. doi: 10.1016/j.jsbmb.2003.10.008 PMID: 15026085
30. Speroni L, Whitt GS, Xylas J, Quinn KP, Jondeau-Cabaton A, et al. (2014) Hormonal regulation of epithelial organization in a three-dimensional breast tissue culture model. Tissue Eng Part C Methods 20: 42-51. doi: 10.1089/ten.tec.2013.0054 PMID: 23675751
31. Clevenger CV, Furth PA, Hankinson SE, Schuler LA (2003) The role of prolactin in mammary carcinoma. Endocr Rev 24: 1-27. doi: 10.1210/er.2001-0036 PMID: 12588805
32. Bole-Feysot C, Goffin V, Edery M, Binart N, Kelly PA (1998) Prolactin (PRL) and its receptor: Actions, signal transduction pathways and phenotypes observed in PRL receptor knockout mice. Endocr Rev 19: 225-268. doi: 10.1210/edrv.19.3.0334 PMID: 9626554
33. Piazza TM, Lu JC, Carver KC, Schuler LA (2009) Src family kinases accelerate prolactin receptor internalization, modulating trafficking and signaling in breast cancer cells. Mol Endocrinol 23: 202-212. doi: 10.1210/me.2008-0341 PMID: 19056863
34. Acosta JJ, Muñoz RM, González L, Subtil-Rodríguez A, Dominguez-Caceres MA, et al. (2003) Src mediates prolactin-dependent proliferation of T47D and MCF7 cells via the activation of focal adhesion kinase/Erk1/2 and phosphatidylinositol 3-kinase pathways. Mol Endocrinol 17: 2268-2282. doi: 10.1210/me.2002-0422 PMID: 12907754
35. Wagner K, Krempler A, Triplett AA, Qi Y, George NM, et al. (2004) Impaired alveologenesis and maintenance of secretory mammary epithelial cells in Jak2 conditional knockout mice. Mol Cell Biol 24: 5510-5520. doi: 10.1128/MCB.24.12.5510-5520.2004 PMID: 15169911
36. Peck AR, Witkiewicz AK, Liu C, Stringer GA, Klimowicz AC, et al. (2011) Loss of nuclear localized and tyrosine phosphorylated Stat5 in breast cancer predicts poor clinical outcome and increased risk of antiestrogen therapy failure. J Clin Oncol 29: 2448-2458. doi: 10.1200/JCO.2010.30.3552 PMID: 21576635
37. Cotarla I, Ren S, Zhang Y, Gehan E, Singh B, et al. (2004) Stat5a is tyrosine phosphorylated and nuclear localized in a high proportion of human breast cancers. Int J Cancer 108: 665-671. doi: 10.1002/ijc.11619 PMID: 14696092
38. Yamashita H, Nishio M, Ando Y, Zhang Z, Hamaguchi M, et al. (2006) Stat5 expression predicts response to endocrine therapy and improves survival in estrogen receptor-positive breast cancer. Endocr Relat Cancer 13: 885-893. doi: 10.1677/erc.1.01095 PMID: 16954437
39. Barcus CE, Keely PJ, Eliceiri KW, Schuler LA (2013) Stiff collagen matrices increase tumorigenic prolactin signailng in breast cancer cells. J Biol Chem 288: 12722-12732. doi: 10.1074/jbc.M112.447631 PMID: 23530035
40. Wozniak MA, Keely PJ (2005) Use of three-dimensional collagen gels to study mechanotransduction in T47D breast epithelial cells. Biol Proced Online 7: 144-161. doi: 10.1251/bpo112 PMID: 16299584
41. Schroeder MD, Symowicz J, Schuler LA (2002) PRL modulates cell cycle regulators in mammary tumor epithelial cells. Mol Endocrinol 16: 45-57. doi: 10.1210/mend.16.1.0762 PMID: 11773438
42. Wilson VS, Bobseine K, Gray LE (2004) Development and characterization of a cell line that stably expresses an estrogen-responsive luciferase reporter for the detection of estrogen receptor agonist and antagonists. Toxicol Sci 81: 69-77. doi: 10.1093/toxsci/kfh180 PMID: 15166400
43. Balaguer P, Francois F, Comunale F, Fenet H, Boussioux A, et al. (1999) Reporter cell lines to study the estroenic effects of xenoestrogens. Sci Total Environ 233: 47-56. doi: 10.1016/S0048-9697(99)00178-3 PMID: 10492897
44. Gutzman JH, Rugowski DE, Nikolai SE, Schuler LA (2007) Stat5 activation inhibits prolactin-induced AP-1 activity: distinct prolactin-initiated signals in tumorigenesis dependent on cell context. Oncogene 26: 6341-6348. doi: 10.1038/sj.onc.1210454 PMID: 17438530
45. Provenzano PP, Inman DR, Eliceiri KW, Keely PJ (2009) Matrix density-induced mechanoregulation of breast cell phenotype, signaling and gene expression through a FAK-ERK linkage. Oncogene 28: 4326-4343. doi: 10.1038/onc.2009.299 PMID: 19826415
46. Roeder BA, Kokini K, Sturgis JE, Robinson JP, Voytik-Harbin SL (2002) Tensile mechanical properties of three-dimensional type I collagen extracellular matrices with varied microstructure. J Biomech Eng 124: 214. doi: 10.1115/1.1449904 PMID: 12002131
47. Gehler S, Baldassarre M, Lad Y, Leight JL, Wozniak MA, et al. (2009) Filamin A-β1 integrin complex tunes epithelial cell response to matrix tension. Mol Biol Cell 20: 3224-3238. doi: 10.1091/mbc.E08-12-1186 PMID: 19458194
48. Brockman JL, Schroeder MD, Schuler LA (2002) PRL activates the cyclin D1 promoter via the Jak2/Stat pathway. Mol Endocrinol 16: 774-784. doi: 10.1210/mend.16.4.0817 PMID: 11923474
49. Chan SR, Rickert CG, Vermi W, Sheehan KCF, Arthur C, et al. (2014) Dysregulated STAT1-SOCS1 control of JAK2 promotes mammary luminal progenitor cell survival and drives ERα(+) tumorigenesis. Cell Death Diff 21: 234-246. doi: 10.1038/cdd.2013.116
50. Schneider CA, Rasband WS, Eliceiri KW (2012) NIH Image to ImageJ: 25 years of image analysis. Nat Methods 9: 671-675. doi: 10.1038/nmeth.2089 PMID: 22930834
51. Provenzano PP, Eliceiri KW, Yan L, Ada-Nguema A, Conklin MW, et al. (2008) Nonlinear optical imaging of cellular processes in breast cancer. Microsc Microanal 14: 532-548. doi: 10.1017/S1431927608080884 PMID: 18986607
52. Bredfeldt JS, Liu Y, Pehlke CA, Conklin MW, Szulczewski JM, et al. (2014) Computational segmentation of collagen fibers from second-harmonic generation images of breast cancer. J Biomed Opt 19: 16007. doi: 10.1117/1.JBO.19.1.016007 PMID: 24407500
53. Lin C-Y, Ström A, Vega VB, Kong SL, Yeo AL, et al. (2004) Discovery of estrogen receptor alpha target genes and response elements in breast tumor cells. Genome Biol 5: R66. doi: 10.1186/gb-2004-5-9-r66 PMID: 15345050
54. Kininis M, Chen BS, Diehl AG, Isaacs GD, Zhang T, et al. (2007) Genomic analyses of transcription factor binding, histone acetylation, and gene expression reveal mechanistically distinct classes of estrogen-regulated promoters. Mol Cell Biol 27: 5090-5104. doi: 10.1128/MCB.00083-07 PMID: 17515612
55. Lu J-C, Piazza TM, Schuler LA (2005) Proteasomes mediate prolactin-induced receptor down-regulation and fragment generation in breast cancer cells. J Biol Chem 280: 33909-33916. doi: 10.1074/jbc.M508118200 PMID: 16103113
56. Swaminathan G, Varghese B, Fuchs SY (2008) Regulation of prolactin receptor levels and activity in breast cancer. J Mammary Gland Biol Neoplasia 13: 81-91. doi: 10.1007/s10911-008-9068-6 PMID: 18204982
57. LaPensee EW, Ben-Jonathan N (2010) Novel roles of prolactin and estrogens in breast cancer: resistance to chemotherapy. Endocr Relat Cancer 17: R91-R107. doi: 10.1677/ERC-09-0253 PMID: 20071456
58. Howell SJ, Anderson E, Hunter T, Farnie G, Clarke RB (2008) Prolactin receptor antagonism reduces the clonogenic capacity of breast cancer cells and potentiates doxorubicin and paclitaxel cytotoxicity. Breast Cancer Res 10: R68. doi: 10.1186/bcr2129 PMID: 18681966
59. Perks CM, Keith AJ, Goodhew KL, Savage PB, Winters ZE, et al. (2004) Prolactin acts as a potent survival factor for human breast cancer cell lines. Br J Cancer 91: 305-311. doi: 10.1038/sj.bjc.6601947 PMID: 15213724
60. Song RX-D, Zhang Z, Santen RJ (2005) Estrogen rapid action via protein complex formation involving ER alpha and Src. Trends in Endocrinol Metabol 16: 347-353. doi: 10.1016/j.tem.2005.06.010
61. Hammes SR, Levin ER (2007) Extranuclear steroid receptors: nature and actions. Endocr Rev 28: 726-741. doi: 10.1210/er.2007-0022 PMID: 17916740
62. Hakak Y, Martin GS (1999) Ubiquitin-dependent degradation of active Src. Curr Biol 9: 1039-1042. doi: 10.1016/S0960-9822(99)80453-9 PMID: 10508617
63. Harris KF, Shoji I, Cooper EM, Kumar S, Oda H, et al. (1999) Ubiquitin-mediated degradation of active Src tyrosine kinase. PNAS 96: 13738-13743. doi: 10.1073/pnas.96.24.13738 PMID: 10570142
64. Hanahan D, Weinberg RA (2011) Hallmarks of cancer: the next generation. Cell 144: 646-674. doi: 10.1016/j.cell.2011.02.013 PMID: 21376230
65. Gilkes DM, Chaturvedi P, Bajpai S, Wong CC, Wei H, et al. (2013) Collagen prolyl hydroxylases are essential for breast cancer metastasis. Cancer Res 73: 3285-3296. doi: 10.1158/0008-5472.CAN-12-3963 PMID: 23539444
66. Greendale GA, Huang M-HH, Ursin G, Ingles S, Stanczyk F, et al. (2007) Serum prolactin levels are positively associated with mammographic density in postmenopausal women. Breast Cancer Res Treat 105: 337-346. doi: 10.1007/s10549-006-9454-y PMID: 17260098
67. Lundström E, Wilczek B, von Palffy Z, Söderqvist G, von Schoultz B (1999) Mammographic breast density during hormone replacement therapy: differences according to treatment. Am J Obstet Gynecol 181: 348-352. doi: 10.1016/S0002-9378(99)70560-0 PMID: 10454681
68. Galbaugh T, Feeney YB, Clevenger CV (2010) Prolactin receptor-integrin cross-talk mediated by SIRPα in breast cancer cells. Mol Cancer Res 8: 1413-1424. doi: 10.1158/1541-7786.MCR-10-0130 PMID: 20826546
69. Miller SL, Antico G, Raghunath PN, Tomaszewski JE, Clevenger CV (2007) Nek3 kinase regulates prolactin-mediated cytoskeletal reorganization and motility of breast cancer cells. Oncogene 26: 4668-4678. doi: 10.1038/sj.onc.1210264 PMID: 17297458
70. Ignatov A, Ignatov T, Roessner A, Costa SD, Kalinski T (2010) Role of GPR30 in the mechanisms of tamoxifen resistance in breast cancer MCF-7 cells. Breast Cancer Res Treat 123: 87-96. doi: 10.1007/s10549-009-0624-6 PMID: 19911269
71. LaPensee EW, Schwemberger SJ, LaPensee CR, Bahassi EM, Afton SE, et al. (2009) Prolactin confers resistance against cisplatin in breast cancer cells by activating glutathione-S-transferase. Carcinogenesis 30: 1298-1304. doi: 10.1093/carcin/bgp120 PMID: 19443905
72. Dowsett M, McGarrick GE, Harris AL, Coombes RC, Smith IE, et al. (1983) Prognostic significance of serum prolactin levels in advanced breast cancer. Br J Cancer 47: 763-769. doi: 10.1038/bjc.1983.129 PMID: 6860546
73. Bhatavdekar JM, Patel DD, Karelia NH, Shah NG, Ghosh N, et al. (1994) Can plasma prolactin predict tamoxifen resistance in patients with advanced breast cancer? Eur J Surg Oncol 20: 118-121. PMID: 8181575
74. Barni S, Lissoni P, Meregalli S, Ardizzoia A, Mengo S, et al. (1998) Clinical efficacy of the aromatase inhibitor anastrozole in relation to prolactin secretion in heavily pretreated metastatic breast cancer. Tumori 84: 45-47. PMID: 9619713
75. Elsberger B, Tan BA, Mitchell TJ, Brown SBF, Mallon EA, et al. (2009) Is expression or activation of Src kinase associated with cancer-specific survival in ER-, PR- and HER2-negative breast cancer patients? Am J Pathol 175: 1389-1397. doi: 10.2353/ajpath.2009.090273 PMID: 19762712
76. Kanomata N, Kurebayashi J, Kozuka Y, Sonoo H, Moriya T (2011) Clinicopathological significance of Y416Src and Y527Src expression in breast cancer. J Clin Pathol 64: 578-586. doi: 10.1136/jclinpath-2011-200042 PMID: 21490376
77. Planas-Silva MD, Bruggeman RD, Grenko RT, Stanley Smith J (2006) Role of c-Src and focal adhesion kinase in progression and metastasis of estrogen receptor-positive breast cancer. Biochem Biophys Res Commun 341: 73-81. doi: 10.1016/j.bbrc.2005.12.164 PMID: 16412380
78. Aksamitiene E, Achanta S, Kolch W, Kholodenko BN, Hoek JB, et al. (2011) Prolactin-stimulated activation of ERK1/2 mitogen-activated protein kinases is controlled by PI3-kinase/Rac/PAK signaling pathway in breast cancer cells. Cell Signal 23: 1794-1805. doi: 10.1016/j.cellsig.2011.06.014 PMID: 21726627
79. Carroll JS, Meyer C, Song J, Li W, Geistlinger TR, et al. (2006) Genome-wide analysis of estrogen receptor binding sites. Nat Genet 38: 1289-1297. doi: 10.1038/ng1901 PMID: 17013392
80. Charn TH, Liu ET-B, Chang EC, Lee YK, Katzenellenbogen JA, et al. (2010) Genome-wide dynamics of chromatin binding of estrogen receptors alpha and beta: mutual restriction and competitive site selection. Mol Endocrinol 24: 47-59. doi: 10.1210/me.2009-0252 PMID: 19897598
81. Nitze LM, Galsgaard ED, Din N, Lund VL, Rasmussen BB, et al. (2013) Reevaluation of the proposed autocrine proliferative function of prolactin in breast cancer. Breast Cancer Res Treat 142: 31-44. doi: 10.1007/s10549-013-2731-7 PMID: 24146212
82. Karey KP, Sirbasku DA (1988) Differential responsiveness of human breast cancer cell lines MCF-7 and T47D to growth factors and 17{beta}-estradiol. Cancer Res 48: 4083-4092. PMID: 3289739
83. Kalyuga M, Gallego-Ortega D, Lee HJ, Roden DL, Cowley MJ, et al. (2012) ELF5 suppresses estrogen sensitivity and underpins the acquisition of antiestrogen resistance in luminal breast cancer. PLoS Biol 10: e1001461. doi: 10.1371/journal.pbio.1001461 PMID: 23300383