oncotomskСибирский онкологический журналSiberian journal of oncology1814-48612312-3168Tomsk National Research Medical Сепtеr of the Russian Academy of Sciences10.21294/1814-4861-2018-17-4-36-40oncotomsk-813Research ArticleЛАБОРАТОРНЫЕ И ЭКСПЕРИМЕНТАЛЬНЫЕ ИССЛЕДОВАНИЯLABORATORY AND EXPERIMENTAL STUDIESСРАВНИТЕЛЬНЫЙ АНАЛИЗ ЭКЗОСОМ КЛЕТОК ЭСТРОГЕН-РЕЗИСТЕНТНОГО РАКА МОЛОЧНОЙ ЖЕЛЕЗЫCOMPARATIVE ANALYSIS OF THE EXOSOMAL CARGO OF THE ESTROGEN-RESISTANT BREAST CANCER CELLSСеминаС. Е.SeminaS. E.

Россия, 115478, г. Москва, Каширское шоссе, 24

кандидат биологических наук, младший научный сотрудник, Научно-исследовательский институт канцерогенеза, Федеральное государственное бюджетное учреждение «Национальный медицинский исследовательский центр онкологии им. Н.Н. Блохина» Минздрава России

Author ID (Scopus): 55919370200

24, Kashirskoye shosse, 115478-Moscow, Russia

PhD, postdoctoral fellow, Institute of Carcinogenesis, the Federal State Budgetary Institution «N.N. BlokhinNational Medical Research Center of Oncology» of the Ministry of Health of Russia

Author ID (Scopus): 55919370200

s.e.semina@gmail.comБарлевН. А.BarlevN. A.

Россия, 194064, г. Санкт-Петербург, Тихорецкий проспект, 4

доктор биологических наук, заместитель директора по науке, Федеральное государственное бюджетное учреждение науки «Институт цитологии Российской академии наук»  

Author ID (Scopus): 6603233870

4, Tikhoretsky prospect, 194064-St. Petersburg, Russia

DSc, Institute of Cytology of the Russian Academy of Sciences 

Author ID (Scopus): 6603233870

nick.a.barlev@gmail.comМиттенбергА. Г.MittenbergA. G.

Россия, 194064, г. Санкт-Петербург, Тихорецкий проспект, 4

кандидат биологических наук, старший научный сотрудник, Федеральное государственное бюджетное учреждение науки «Институт цитологии Российской академии наук» 

Author ID (Scopus): 6602089287

4, Tikhoretsky prospect, 194064-St. Petersburg, Russia

PhD, Senior scientist of laboratory of Regulation of Gene Expression, Institute of Cytology of the Russian Academy of Sciences

Author ID (Scopus): 6602089287

a.mittenberg@gmail.comКрасильниковМ. А.KrasilnikovM. A.

Россия, 115478, г. Москва, Каширское шоссе, 24

доктор биологических наук, профессор, директор, Научно-исследовательский институт  канцерогенеза, Федеральное государственное бюджетное учреждение «Национальный  медицинский исследовательский центр онкологии им. Н.Н. Блохина» Минздрава России

Author ID (Scopus): 7005790120

24, Kashirskoye shosse, 115478-Moscow, Russia

DSc, Professor, Director of Institute of Carcinogenesis, the Federal State Budgetary Institution «N.N. Blokhin National Medical Research Center of Oncology» of the Ministry of Health of Russia

Author ID (Scopus): 7005790120

krasilnikovm@main.crc.umos.ruНаучно-исследовательский институт канцерогенеза, Федеральное государственное бюджетное учреждение «Национальный медицинский исследовательский центр онкологии им. Н.Н. Блохина» Минздрава РоссииРоссияInstitute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of RussiaRussian FederationФедеральное государственное бюджетное учреждение науки «Институт цитологии Российской академии наук»РоссияInstitute of Cytology of the Russian Academy of SciencesRussian Federation2018010920181743640Copyright © Семина С.Е., Барлев Н.А., Миттенберг А.Г., Красильников М.А., 20182018Семина С.Е., Барлев Н.А., Миттенберг А.Г., Красильников М.А.Semina S.E., Barlev N.A., Mittenberg A.G., Krasilnikov M.A.This work is licensed under a Creative Commons Attribution 4.0 License.https://www.siboncoj.ru/jour/article/view/813

Участие экзосом в патогенезе злокачественных опухолей основано на их способности проникать внутрь  клеток-реципиентов, вызывая в последних каскад генетических и эпигенетических изменений. Ранее мы  показали, что экзосомы, продуцируемые различными вариантами эстроген-независимых сублиний клеток  рака молочной железы (MCF-7/T, полученной в результате длительного культивирования клеток в  присутствии антиэстрогена тамоксифена, и MCF-7/M, полученной в результате культивирования клеток с  метформином), способны индуцировать резистентность в родительских клетках MCF-7. В настоящей работе  для исследования характерных особенностей состава экзосом резистентных клеток был проведен  сравнительный анализ протеома и профиля микроРНК контрольных экзосом и экзосом, полученных от  резистентных сублиний. В целом в образцах экзосом было идентифицировано более 400 белков, из которых  только 2 белка, DMBT1 (Deleted in Malignant Brain Tumors 1) и THBS1 (Thrombospondin-1), были  гиперэкспрессированы в обоих типах резистентных экзосом (менее 5 % от общего количества белков,  дифференциально экспрессированных в экзосомах резистетных клеток), что свидетельствует об уникальном  составе экзосомальных белков для каждого типа резистентных клеток. Сравнительный анализ  состава микроРНК, дифференциально экспрессированных в обоих вариантах экзосом резистентных клеток,  выявил 180 гиперэкспрессированных микроРНК и 202 микроРНК с пониженной экспрессией. Среди них 4  гиперэкспрессированных и 8 гипоэкспрессированных микроРНК оказались ассоциированы с развитием  гормональной резистентности клеток рака молочной железы. Биоинформатический анализ 4  гиперэкспрессированных микроРНК выявил 2 микроРНК, mir-101и mir-181b, участвующих в стимуляции PI3K  сигналинга, свидетельствуя о важной роли последнего в развитии гормональной резистентности  клеток рака молочной железы. 

The exosomes involvement in the pathogenesis of tumors is based on their property to incorporate into the recipient cells resulting in the both genomic and epigenomic changes.  Earlier we have shown that exosomes from different types of estrogen-independent breast  cancer cells (MCF-7/T developed by long-term tamoxifen treatment, and MCF-7/M)  developed by metformin treatment were able to transfer resistance to the parent MCF-7  cells. To elucidate the common features of the both types of resistant exosomes, the  proteome and microRNA cargo of the control and both types of the resistant exosomes were  analyzed. Totally, more than 400 proteins were identified in the exosome samples. Of these  proteins, only two proteins, DMBT1 (Deleted in Malignant Brain Tumors 1) and THBS1  (Thrombospondin-1), were commonly expressed in the both resistant exosomes (less than  5% from total DEPs) demonstrating the unique protein composition of each type of the resistant exosomes. The comparative analysis of the miRNA differentially expressed in  the both MCF-7/T and MCF-7/M resistant exosomes revealed 180 up-regulated and 202  down-regulated miRNAs. Among them, 4 up-regulated and 8 down-regulated miRNAs were  associated with progression of hormonal resistance of breast tumors. The bioinformatical  analysis of 4 up-regulated exosomal miRNAs revealed 2 miRNAs, mir- 101and mir-181b, which up-regulated PI3K signaling  supporting the key role of PI3K/Akt in the development of the resistant phenotype of breast cancer cells.

рак молочной железытамоксифенэкзосомыгормональная резистентностьмикроРНКbreast cancertamoxifenexosomeshormonal resistancemicroRNAReferencesAdmyre C., Johansson S.M., Qazi K.R., Filén J.J., Lahesmaa R., Norman M., Neve E.P., Scheynius A., Gabrielsson S. Exosomes with immune modulatory features are present in human breast milk. J Immunol. 2007 Aug 1; 179(3): 1969–78.Admyre C., Johansson S.M., Qazi K.R., Filén J.J., Lahesmaa R., Norman M., Neve E.P., Scheynius A., Gabrielsson S. Exosomes with immune modulatory features are present in human breast milk. J Immunol. 2007 Aug 1; 179(3): 1969–78.Jenjaroenpun P., Kremenska Y., Nair V.M., Kremenskoy M., Joseph B., Kurochkin I.V. Characterization of RNA in exosomes secreted by human breast cancer cell lines using next-generation sequencing. PeerJ. 2013 Nov 5; 1: e201. doi: 10.7717/peerj.201.Jenjaroenpun P., Kremenska Y., Nair V.M., Kremenskoy M., Joseph B., Kurochkin I.V. Characterization of RNA in exosomes secreted by human breast cancer cell lines using next-generation sequencing. PeerJ. 2013 Nov 5; 1: e201. doi: 10.7717/peerj.201.Melo S.A., Sugimoto H., O'Connell J.T., Kato N., Villanueva A., Vidal A., Qiu L., Vitkin E., Perelman L.T., Melo C.A., Lucci A., Ivan C., Calin G.A., Kalluri R. Cancer exosomes perform cell-independent micro- RNA biogenesis and promote tumorigenesis. Cancer Cell. 2014 Nov 10; 26(5): 707–21. doi: 10.1016/j.ccell.2014.09.005.Melo S.A., Sugimoto H., O'Connell J.T., Kato N., Villanueva A., Vidal A., Qiu L., Vitkin E., Perelman L.T., Melo C.A., Lucci A., Ivan C., Calin G.A., Kalluri R. Cancer exosomes perform cell-independent micro- RNA biogenesis and promote tumorigenesis. Cancer Cell. 2014 Nov 10; 26(5): 707–21. doi: 10.1016/j.ccell.2014.09.005.Wei Y., Lai X., Yu S., Chen S., Ma Y., Zhang Y., Li H., Zhu X., Yao L., Zhang J. Exosomal miR-221/222 enhances tamoxifen resistance in recipient ER-positive breast cancer cells. Breast Cancer Res Treat. 2014 Sep; 147(2): 423–31. doi: 10.1007/s10549-014-3037-0.Wei Y., Lai X., Yu S., Chen S., Ma Y., Zhang Y., Li H., Zhu X., Yao L., Zhang J. Exosomal miR-221/222 enhances tamoxifen resistance in recipient ER-positive breast cancer cells. Breast Cancer Res Treat. 2014 Sep; 147(2): 423–31. doi: 10.1007/s10549-014-3037-0.Zhang J., Li S., Li L., Li M., Guo C., Yao J., Mi S. Exosome and exosomal microRNA: trafficking, sorting, and function. Genomics Proteomics Bioinformatics. 2015 Feb; 13(1): 17–24. doi: 10.1016/j.gpb.2015.02.001.Zhang J., Li S., Li L., Li M., Guo C., Yao J., Mi S. Exosome and exosomal microRNA: trafficking, sorting, and function. Genomics Proteomics Bioinformatics. 2015 Feb; 13(1): 17–24. doi: 10.1016/j.gpb.2015.02.001.Rupp A.K., Rupp C., Keller S., Brase J.C., Ehehalt R., Fogel M., Moldenhauer G., Marmé F., Sültmann H., Altevogt P. Loss of EpCAM expression in breast cancer derived serum exosomes: role of proteolytic cleavage. Gynecol Oncol. 2011 Aug; 122(2): 437– 46. doi: 10.1016/j.ygyno.2011.04.035.Rupp A.K., Rupp C., Keller S., Brase J.C., Ehehalt R., Fogel M., Moldenhauer G., Marmé F., Sültmann H., Altevogt P. Loss of EpCAM expression in breast cancer derived serum exosomes: role of proteolytic cleavage. Gynecol Oncol. 2011 Aug; 122(2): 437– 46. doi: 10.1016/j.ygyno.2011.04.035.Weidle U.H., Birzele F., Kollmorgen G., Rüger R. The Multiple Roles of Exosomes in Metastasis. Cancer Genomics Proteomics. 2017 Jan 2; 14(1): 1–15. doi: 10.21873/cgp.20015.Weidle U.H., Birzele F., Kollmorgen G., Rüger R. The Multiple Roles of Exosomes in Metastasis. Cancer Genomics Proteomics. 2017 Jan 2; 14(1): 1–15. doi: 10.21873/cgp.20015.Sansone P., Savini C., Kurelac I., Chang Q., Amato L.B., Strillacci A., Stepanova A., Iommarini L., Mastroleo C., Daly L., Galkin A., Thakur B.K., Soplop N., Uryu K., Hoshino A., Norton L., Bonafé M., Cricca M., Gasparre G., Lyden D., Bromberg J. Packaging and transfer of mitochondrial DNA via exosomes regulate escape from dormancy in hormonal therapy-resistant breast cancer. Proc Natl Acad Sci U S A. 2017 Oct 24; 114(43): E9066‑E9075. doi: 10.1073/pnas.1704862114.Sansone P., Savini C., Kurelac I., Chang Q., Amato L.B., Strillacci A., Stepanova A., Iommarini L., Mastroleo C., Daly L., Galkin A., Thakur B.K., Soplop N., Uryu K., Hoshino A., Norton L., Bonafé M., Cricca M., Gasparre G., Lyden D., Bromberg J. Packaging and transfer of mitochondrial DNA via exosomes regulate escape from dormancy in hormonal therapy-resistant breast cancer. Proc Natl Acad Sci U S A. 2017 Oct 24; 114(43): E9066‑E9075. doi: 10.1073/pnas.1704862114.Chen W.X., Liu X.M., Lv M.M., Chen L., Zhao J.H., Zhong S.L., Ji M.H., Hu Q., Luo Z., Wu J.Z., Tang J.H. Exosomes from drug-resistant breast cancer cells transmit chemoresistance by a horizontal transfer of microRNAs. PLoS One. 2014 Apr 16; 9(4): e95240. doi: 10.1371/journal.pone.0095240.Chen W.X., Liu X.M., Lv M.M., Chen L., Zhao J.H., Zhong S.L., Ji M.H., Hu Q., Luo Z., Wu J.Z., Tang J.H. Exosomes from drug-resistant breast cancer cells transmit chemoresistance by a horizontal transfer of microRNAs. PLoS One. 2014 Apr 16; 9(4): e95240. doi: 10.1371/journal.pone.0095240.Jaiswal R., Luk F., Dalla P.V., Grau G.E., Bebawy M. Breast cancer-derived microparticles display tissue selectivity in the transfer of resistance proteins to cells. PLoS One. 2013 Apr 12; 8(4): e61515. doi: 10.1371/journal.pone.0061515.Jaiswal R., Luk F., Dalla P.V., Grau G.E., Bebawy M. Breast cancer-derived microparticles display tissue selectivity in the transfer of resistance proteins to cells. PLoS One. 2013 Apr 12; 8(4): e61515. doi: 10.1371/journal.pone.0061515.Semina S.E., Scherbakov A.M., Vnukova A.A., Bagrov D.V., Evtushenko E.G., Safronova V.M., Golovina D.A., Lyubchenko L.N., Gudkova M.V., Krasil'nikov M.A. Exosome-Mediated Transfer of Cancer Cell Resistance to Antiestrogen Drugs. Molecules. 2018 Apr 4; 23(4). pii: E829. doi: 10.3390/molecules23040829.Semina S.E., Scherbakov A.M., Vnukova A.A., Bagrov D.V., Evtushenko E.G., Safronova V.M., Golovina D.A., Lyubchenko L.N., Gudkova M.V., Krasil'nikov M.A. Exosome-Mediated Transfer of Cancer Cell Resistance to Antiestrogen Drugs. Molecules. 2018 Apr 4; 23(4). pii: E829. doi: 10.3390/molecules23040829.Tchatchou S., Riedel A., Lyer S., Schmutzhard J., Strobel-Freidekind O., Gronert- Sum S., Mietag C., D'Amato M., Schlehe B., Hemminki K., Sutter C., Ditsch N., Blackburn A., Hill L.Z., Jerry D.J., Bugert P., Weber B.H., Niederacher D., Arnold N., Varon-Mateeva R., Wappenschmidt B., Schmutzler R.K., Engel C., Meindl A., Bartram C.R., Mollenhauer J., Burwinkel B. Identification of a DMBT1 polymorphism associated with increased breast cancer risk and decreased promoter activity. Hum Mutat. 2010 Jan; 31(1): 60–6. doi: 10.1002/humu.21134.Tchatchou S., Riedel A., Lyer S., Schmutzhard J., Strobel-Freidekind O., Gronert- Sum S., Mietag C., D'Amato M., Schlehe B., Hemminki K., Sutter C., Ditsch N., Blackburn A., Hill L.Z., Jerry D.J., Bugert P., Weber B.H., Niederacher D., Arnold N., Varon-Mateeva R., Wappenschmidt B., Schmutzler R.K., Engel C., Meindl A., Bartram C.R., Mollenhauer J., Burwinkel B. Identification of a DMBT1 polymorphism associated with increased breast cancer risk and decreased promoter activity. Hum Mutat. 2010 Jan; 31(1): 60–6. doi: 10.1002/humu.21134.Mollenhauer J., Helmke B., Medina D., Bergmann G., Gassler N., Müller H., Lyer S., Diedrichs L., Renner M., Wittig R., Blaich S., Hamann U., Madsen J., Holmskov U., Bikker F., Ligtenberg A., Carlén A., Olsson J., Otto H.F., O'Malley B., Poustka A. Carcinogen inducibility in vivo and down-regulation of DMBT1 during breast carcinogenesis. Genes Chromosomes Cancer. 2004 Mar; 39(3): 185–94.Mollenhauer J., Helmke B., Medina D., Bergmann G., Gassler N., Müller H., Lyer S., Diedrichs L., Renner M., Wittig R., Blaich S., Hamann U., Madsen J., Holmskov U., Bikker F., Ligtenberg A., Carlén A., Olsson J., Otto H.F., O'Malley B., Poustka A. Carcinogen inducibility in vivo and down-regulation of DMBT1 during breast carcinogenesis. Genes Chromosomes Cancer. 2004 Mar; 39(3): 185–94.Wang T., Srivastava S., Hartman M., Buhari S.A., Chan C.W., Iau P., Khin L.W., Wong A., Tan S.H., Goh B.C., Lee S.C. High expression of intratumoral stromal proteins is associated with chemotherapy resistance in breast cancer. Oncotarget. 2016 Aug 23; 7(34): 55155‑55168. doi: 10.18632/oncotarget.10894.Wang T., Srivastava S., Hartman M., Buhari S.A., Chan C.W., Iau P., Khin L.W., Wong A., Tan S.H., Goh B.C., Lee S.C. High expression of intratumoral stromal proteins is associated with chemotherapy resistance in breast cancer. Oncotarget. 2016 Aug 23; 7(34): 55155‑55168. doi: 10.18632/oncotarget.10894.Kang J.H., Kim H.J., Park M.K., Lee C.H. Sphingosylphosphorylcholine Induces Thrombospondin-1 Secretion in MCF10A Cells via ERK2. Biomol Ther (Seoul). 2017 Nov 1; 25(6): 625–633. doi: 10.4062/biomolther.2016.228.Kang J.H., Kim H.J., Park M.K., Lee C.H. Sphingosylphosphorylcholine Induces Thrombospondin-1 Secretion in MCF10A Cells via ERK2. Biomol Ther (Seoul). 2017 Nov 1; 25(6): 625–633. doi: 10.4062/biomolther.2016.228.Sachdeva M., Wu H., Ru P., Hwang L., Trieu V., Mo Y.Y. MicroRNA-101-mediated Akt activation and estrogen-independent growth. Oncogene. 2011 Feb 17; 30(7): 822–31. doi: 10.1038/onc.2010.463.Sachdeva M., Wu H., Ru P., Hwang L., Trieu V., Mo Y.Y. MicroRNA-101-mediated Akt activation and estrogen-independent growth. Oncogene. 2011 Feb 17; 30(7): 822–31. doi: 10.1038/onc.2010.463.Muluhngwi P., Klinge C.M. Identification of miRNAs as biomarkers for acquired endocrine resistance in breast cancer. Mol Cell Endocrinol. 2017 Nov 15; 456: 76–86. doi: 10.1016/j.mce.2017.02.004.Muluhngwi P., Klinge C.M. Identification of miRNAs as biomarkers for acquired endocrine resistance in breast cancer. Mol Cell Endocrinol. 2017 Nov 15; 456: 76–86. doi: 10.1016/j.mce.2017.02.004.Ye P., Fang C., Zeng H., Shi Y., Pan Z., An N., He K., Zhang L., Long X. Differential microRNA expression profiles in tamoxifen-resistant human breast cancer cell lines induced by two methods. Oncol Lett. 2018 Mar; 15(3): 3532–3539. doi: 10.3892/ol.2018.7768.Ye P., Fang C., Zeng H., Shi Y., Pan Z., An N., He K., Zhang L., Long X. Differential microRNA expression profiles in tamoxifen-resistant human breast cancer cell lines induced by two methods. Oncol Lett. 2018 Mar; 15(3): 3532–3539. doi: 10.3892/ol.2018.7768.Miller T.E., Ghoshal K., Ramaswamy B., Roy S., Datta J., Shapiro C.L., Jacob S., Majumder S. MicroRNA-221/222 confers tamoxifen resistance in breast cancer by targeting p27Kip1. J Biol Chem. 2008 Oct 31; 283(44): 29897–903. doi: 10.1074/jbc.M804612200.Miller T.E., Ghoshal K., Ramaswamy B., Roy S., Datta J., Shapiro C.L., Jacob S., Majumder S. MicroRNA-221/222 confers tamoxifen resistance in breast cancer by targeting p27Kip1. J Biol Chem. 2008 Oct 31; 283(44): 29897–903. doi: 10.1074/jbc.M804612200.Zhao Y., Deng C., Lu W., Xiao J., Ma D., Guo M., Recker R.R., Gatalica Z., Wang Z., Xiao G.G. let-7 microRNAs induce tamoxifen sensitivity by downregulation of estrogen receptor alpha signaling in breast cancer. Mol Med. 2011; 17(11‑12): 1233–41. doi: 10.2119/molmed.2010.00225.Zhao Y., Deng C., Lu W., Xiao J., Ma D., Guo M., Recker R.R., Gatalica Z., Wang Z., Xiao G.G. let-7 microRNAs induce tamoxifen sensitivity by downregulation of estrogen receptor alpha signaling in breast cancer. Mol Med. 2011; 17(11‑12): 1233–41. doi: 10.2119/molmed.2010.00225.Ke K., Lou T. MicroRNA-10a suppresses breast cancer progression via PI3K/Akt/mTOR pathway. Oncol Lett. 2017 Nov; 14(5): 5994–6000. doi: 10.3892/ol.2017.6930.Ke K., Lou T. MicroRNA-10a suppresses breast cancer progression via PI3K/Akt/mTOR pathway. Oncol Lett. 2017 Nov; 14(5): 5994–6000. doi: 10.3892/ol.2017.6930.Chen X., Wang Y.W., Gao P. SPIN1, negatively regulated by miR-148/152, enhances Adriamycin resistance via upregulating drug metabolizing enzymes and transporter in breast cancer. J Exp Clin Cancer Res. 2018 May 9; 37(1): 100. doi: 10.1186/s13046-018-0748-9.Chen X., Wang Y.W., Gao P. SPIN1, negatively regulated by miR-148/152, enhances Adriamycin resistance via upregulating drug metabolizing enzymes and transporter in breast cancer. J Exp Clin Cancer Res. 2018 May 9; 37(1): 100. doi: 10.1186/s13046-018-0748-9.Sharifi M., Moridnia A. Apoptosis-inducing and antiproliferative effect by inhibition of miR-182-5p through the regulation of CASP9 expression in human breast cancer. Cancer Gene Ther. 2017 Feb; 24(2): 75‑82. doi: 10.1038/cgt.2016.79.Sharifi M., Moridnia A. Apoptosis-inducing and antiproliferative effect by inhibition of miR-182-5p through the regulation of CASP9 expression in human breast cancer. Cancer Gene Ther. 2017 Feb; 24(2): 75‑82. doi: 10.1038/cgt.2016.79.Rhodes L.V., Martin E.C., Segar H.C., Miller D.F., Buechlein A., Rusch D.B., Nephew K.P., Burow M.E., Collins-Burow B.M. Dual regulation by microRNA-200b-3p and microRNA-200b-5p in the inhibition of epithelial-to-mesenchymal transition in triple- negative breast cancer. Oncotarget. 2015 Jun 30; 6(18): 16638–52.Rhodes L.V., Martin E.C., Segar H.C., Miller D.F., Buechlein A., Rusch D.B., Nephew K.P., Burow M.E., Collins-Burow B.M. Dual regulation by microRNA-200b-3p and microRNA-200b-5p in the inhibition of epithelial-to-mesenchymal transition in triple- negative breast cancer. Oncotarget. 2015 Jun 30; 6(18): 16638–52.Li X., Wu Y., Liu A., Tang X. MiR-27b is epigenetically downregulated in tamoxifen resistant breast cancer cells due to promoter methylation and regulates tamoxifen sensitivity by targeting HMGB3. Biochem Biophys Res Commun. 2016 Sep 2; 477(4): 768–773. doi: 10.1016/j.bbrc.2016.06.133.Li X., Wu Y., Liu A., Tang X. MiR-27b is epigenetically downregulated in tamoxifen resistant breast cancer cells due to promoter methylation and regulates tamoxifen sensitivity by targeting HMGB3. Biochem Biophys Res Commun. 2016 Sep 2; 477(4): 768–773. doi: 10.1016/j.bbrc.2016.06.133.Zhu J., Zou Z., Nie P., Kou X., Wu B., Wang S., Song Z., He J. Downregulation of microRNA-27b-3p enhances tamoxifen resistance in breast cancer by increasing NR5A2 and CREB1 expression. Cell Death Dis. 2016 Nov 3; 7(11): e2454. doi: 10.1038/cddis.2016.361.Zhu J., Zou Z., Nie P., Kou X., Wu B., Wang S., Song Z., He J. Downregulation of microRNA-27b-3p enhances tamoxifen resistance in breast cancer by increasing NR5A2 and CREB1 expression. Cell Death Dis. 2016 Nov 3; 7(11): e2454. doi: 10.1038/cddis.2016.361.Joshi T., Elias D., Stenvang J., Alves C.L., Teng F., Lyng M.B., Lykkesfeldt A.E., Brünner N., Wang J., Gupta R., Workman C.T., Ditzel H.J. Integrative analysis of miRNA and gene expression reveals regulatory networks in tamoxifen-resistant breast cancer. Oncotarget. 2016 Aug 30; 7(35): 57239–57253. doi: 10.18632/oncotarget.11136.Joshi T., Elias D., Stenvang J., Alves C.L., Teng F., Lyng M.B., Lykkesfeldt A.E., Brünner N., Wang J., Gupta R., Workman C.T., Ditzel H.J. Integrative analysis of miRNA and gene expression reveals regulatory networks in tamoxifen-resistant breast cancer. Oncotarget. 2016 Aug 30; 7(35): 57239–57253. doi: 10.18632/oncotarget.11136.Muluhngwi P., Alizadeh-Rad N., Vittitow S.L., Kalbfleisch T.S., Klinge C.M. The miR- 29 transcriptome in endocrine-sensitive and resistant breast cancer cells. Sci Rep. 2017 Jul 12; 7(1): 5205. doi: 10.1038/s41598-017-05727-w.Muluhngwi P., Alizadeh-Rad N., Vittitow S.L., Kalbfleisch T.S., Klinge C.M. The miR- 29 transcriptome in endocrine-sensitive and resistant breast cancer cells. Sci Rep. 2017 Jul 12; 7(1): 5205. doi: 10.1038/s41598-017-05727-w.Baran-Gale J., Purvis J.E., Sethupathy P. An integrative transcriptomics approach identifies miR-503 as a candidate master regulator of the estrogen response in MCF-7 breast cancer cells. RNA. 2016 Oct; 22(10): 1592–603. doi: 10.1261/rna.056895.116.Baran-Gale J., Purvis J.E., Sethupathy P. An integrative transcriptomics approach identifies miR-503 as a candidate master regulator of the estrogen response in MCF-7 breast cancer cells. RNA. 2016 Oct; 22(10): 1592–603. doi: 10.1261/rna.056895.116.Osborne C.K., Schiff R. Mechanisms of endocrine resistance in breast cancer. Annu Rev Med. 2011; 62: 233–47. doi: 10.1146/annurevmed-070909-182917.Osborne C.K., Schiff R. Mechanisms of endocrine resistance in breast cancer. Annu Rev Med. 2011; 62: 233–47. doi: 10.1146/annurevmed-070909-182917.

The authors declare that there are no conflicts of interest present.