Coordinate Suppression of ERBB2 and ERBB3 by Enforced Expression of Micro-RNA miR-125a or miR-125b

Deregulation of micro-RNAs (miRNAs) is emerging as a major aspect of cancer etiology because their capacity to direct the translation and stability of targeted transcripts can dramatically influence cellular physiology. To explore the potential of exogenously applied miRNAs to suppress oncogenic proteins, the ERBB oncogene family was chosen with a bioinformatics search identifying targeting seed sequences for miR-125a and miR-125b within the 3′-untranslated regions of both ERBB2 and ERBB3. Using the human breast cancer cell line SKBR3 as a model for ERBB2 and ERBB3 dependence, infection of these cells with retroviral constructs expressing either miR-125a or miR-125b resulted in suppression of ERBB2 and ERBB3 at both the transcript and protein level. Luciferase constructs containing the 3′ 3′-untranslated regions of ERBB2 and ERBB3 demonstrated ∼35% less activity in miR-125a- and miR-125b-expressing cells relative to controls. Additionally, phosphorylation of ERK1/2 and AKT was suppressed in SKBR3 cells overexpressing either miR-125a or miR-125b. Consistent with suppression of both ERBB2 and ERBB3 signaling, miR-125a-or miR-125b-overexpressing SKBR3 cells were impaired in their anchorage-dependent growth and exhibited reduced migration and invasion capacities. Parallel studies performed on MCF10A cells demonstrated that miR-125a or miR-125b overexpression produced only marginal influences on the growth and migration of these non-transformed human mammary epithelial cells. These results illustrate the feasibility of using miRNAs as a therapeutic strategy to suppress oncogene expression and function. Deregulation of micro-RNAs (miRNAs) is emerging as a major aspect of cancer etiology because their capacity to direct the translation and stability of targeted transcripts can dramatically influence cellular physiology. To explore the potential of exogenously applied miRNAs to suppress oncogenic proteins, the ERBB oncogene family was chosen with a bioinformatics search identifying targeting seed sequences for miR-125a and miR-125b within the 3′-untranslated regions of both ERBB2 and ERBB3. Using the human breast cancer cell line SKBR3 as a model for ERBB2 and ERBB3 dependence, infection of these cells with retroviral constructs expressing either miR-125a or miR-125b resulted in suppression of ERBB2 and ERBB3 at both the transcript and protein level. Luciferase constructs containing the 3′ 3′-untranslated regions of ERBB2 and ERBB3 demonstrated ∼35% less activity in miR-125a- and miR-125b-expressing cells relative to controls. Additionally, phosphorylation of ERK1/2 and AKT was suppressed in SKBR3 cells overexpressing either miR-125a or miR-125b. Consistent with suppression of both ERBB2 and ERBB3 signaling, miR-125a-or miR-125b-overexpressing SKBR3 cells were impaired in their anchorage-dependent growth and exhibited reduced migration and invasion capacities. Parallel studies performed on MCF10A cells demonstrated that miR-125a or miR-125b overexpression produced only marginal influences on the growth and migration of these non-transformed human mammary epithelial cells. These results illustrate the feasibility of using miRNAs as a therapeutic strategy to suppress oncogene expression and function. Micro-RNAs (miRNAs) 2The abbreviations used are: miRNA, micro-RNA; RISC, RNA-induced silencing complex; nt, nucleotide(s); UTR, untranslated region; EGF, epidermal growth factor; EGFR, EGF receptor; ERK, extracellular signal-regulated kinase. comprise a large class of regulatory noncoding RNAs capable of exerting pronounced influences upon the translation and stability of mRNAs (1Bartel D.P. 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Additional impetus to understanding their biology has emerged from growing evidence implicating miRNA deregulation in cancer etiology (5Calin G.A. Dumitru C.D. Shimizu M. Bichi R. Zupo S. Noch E. Aldler H. Rattan S. Keating M. Rai K. Rassenti L. Kipps T. Negrini M. Bullrich F. Croce C.M. Proc. Natl. Acad. Sci. U. S. A. 2002; 99: 15524-15529Crossref PubMed Scopus (4240) Google Scholar, 6Michael M.Z. O'Connor S.M. VanHolst Pellekaan N.G. Young G.P. James R.J. Mol. Cancer Res. 2003; 1: 882-891PubMed Google Scholar, 7Lu J. Getz G. Miska E.A. Alvarez-Saavedra E. Lamb J. Peck D. Sweet-Cordero A. Ebert B.L. Mak R.H. Ferrando A.A. Downing J.R. Jacks T. Horvitz H.R. Golub T.R. Nature. 2005; 435: 834-838Crossref PubMed Scopus (8237) Google Scholar, 8Iorio M.V. Ferracin M. Liu C.-G. Veronese A. Spizzo R. Sabbioni S. Magri E. Pedriali M. Fabbri M. Campiglio M. Menard S. Palazzo J.P. Rosenberg A. Musiani P. Volinia S. Nenci I. Calin G.A. Querzoli P. Negrini M. Croce C.M. Cancer Res. 2005; 65: 7065-7070Crossref PubMed Scopus (3487) Google Scholar). More than 400 human miRNAs have been identified to date with up to ∼1000 miRNAs postulated to exist on the basis of bioinformatics analyses, leading to the speculation that a majority of human mRNAs are subject to miRNA regulation (9Lewis B.P. Burge C.B. Bartel D.P. Cell. 2005; 120: 15-20Abstract Full Text Full Text PDF PubMed Scopus (9882) Google Scholar, 10Berezikov E. Guryev V. van de Belt J. Wienholds E. Plasterk R.H.A. Cuppen E. Cell. 2005; 120: 21-24Abstract Full Text Full Text PDF PubMed Scopus (1068) Google Scholar). miRNAs are initially excised from a primary RNA transcript in the nucleus by the nuclear RNase III endonucleases Drosha working in cooperation with DGCR8 (4Kim V.N. Nat. Rev. Mol. Cell Biol. 2005; 6: 376-385Crossref PubMed Scopus (1999) Google Scholar, 11Han J. Lee Y. Yeom K. Nam J. Heo I. Rhee J. Sohn Y. Cho Y. Zhang B. Kim V.N. Cell. 2006; 125: 887-901Abstract Full Text Full Text PDF PubMed Scopus (1179) Google Scholar). Export to the cytoplasm is facilitated by exportin-5, where the ∼70-nt pre-miRNA is further processed by the RNase III endonuclease Dicer into a mature ∼22-nt double-stranded miRNA (1Bartel D.P. Cell. 2004; 116: 281-297Abstract Full Text Full Text PDF PubMed Scopus (29622) Google Scholar, 2Ambros V. Nature. 2004; 431: 350-355Crossref PubMed Scopus (9088) Google Scholar, 3Zamore P.D. Haley B. Science. 2005; 309: 1519-1524Crossref PubMed Scopus (1130) Google Scholar, 4Kim V.N. Nat. Rev. Mol. Cell Biol. 2005; 6: 376-385Crossref PubMed Scopus (1999) Google Scholar). Subsequent incorporation of one strand into RISC (RNA-induced silencing complex) establishes the miRNA as competent to target mRNAs for translational arrest and, in some instances, transcript decay (1Bartel D.P. Cell. 2004; 116: 281-297Abstract Full Text Full Text PDF PubMed Scopus (29622) Google Scholar, 2Ambros V. Nature. 2004; 431: 350-355Crossref PubMed Scopus (9088) Google Scholar, 3Zamore P.D. Haley B. Science. 2005; 309: 1519-1524Crossref PubMed Scopus (1130) Google Scholar). Although targeting of a mRNA by a miRNA remains a poorly defined process, it appears to be largely mediated by complementarity between nucleotides 2 to 5 (numbered from the miRNA 5′ end), occasionally referred to as the “seed sequences,” with a target element in the transcript 3′-UTR (1Bartel D.P. Cell. 2004; 116: 281-297Abstract Full Text Full Text PDF PubMed Scopus (29622) Google Scholar, 2Ambros V. Nature. 2004; 431: 350-355Crossref PubMed Scopus (9088) Google Scholar, 3Zamore P.D. Haley B. Science. 2005; 309: 1519-1524Crossref PubMed Scopus (1130) Google Scholar, 9Lewis B.P. Burge C.B. Bartel D.P. Cell. 2005; 120: 15-20Abstract Full Text Full Text PDF PubMed Scopus (9882) Google Scholar, 12Lim L.P. Lau N.C. Garrett-Engele P. Grimson A. Schelter J.M. Castle J. Bartel D.P. Linsley P.S. Johnson J.M. Nature. 2005; 433: 769-773Crossref PubMed Scopus (4007) Google Scholar). Involvement of miRNAs in the oncogenic process has been supported by the observation that the 13q14 deletion characterizing more than half of all chronic lymphocytic leukemias results in loss of miR-15a and miR-16-1 genes (5Calin G.A. Dumitru C.D. Shimizu M. Bichi R. Zupo S. Noch E. Aldler H. Rattan S. Keating M. Rai K. Rassenti L. Kipps T. Negrini M. Bullrich F. Croce C.M. Proc. Natl. Acad. Sci. U. S. A. 2002; 99: 15524-15529Crossref PubMed Scopus (4240) Google Scholar). Additional studies using microarray profiling have demonstrated aberrant expression of miRNAs in human cancers, with deregulation of specific miRNAs distinguishing different cancer types (7Lu J. Getz G. Miska E.A. Alvarez-Saavedra E. Lamb J. Peck D. Sweet-Cordero A. Ebert B.L. Mak R.H. Ferrando A.A. Downing J.R. Jacks T. Horvitz H.R. Golub T.R. Nature. 2005; 435: 834-838Crossref PubMed Scopus (8237) Google Scholar, 8Iorio M.V. Ferracin M. Liu C.-G. Veronese A. Spizzo R. Sabbioni S. Magri E. Pedriali M. Fabbri M. Campiglio M. Menard S. Palazzo J.P. Rosenberg A. Musiani P. Volinia S. Nenci I. Calin G.A. Querzoli P. Negrini M. Croce C.M. Cancer Res. 2005; 65: 7065-7070Crossref PubMed Scopus (3487) Google Scholar). One breast cancer study concluded that two up-regulated miRNAs (miR-21, miR-155) might act as oncogenes, whereas three other down-regulated miRNAs (miR-10b, miR-125b, and miR-145) might act as breast cancer suppressor genes (8Iorio M.V. Ferracin M. Liu C.-G. Veronese A. Spizzo R. Sabbioni S. Magri E. Pedriali M. Fabbri M. Campiglio M. Menard S. Palazzo J.P. Rosenberg A. Musiani P. Volinia S. Nenci I. Calin G.A. Querzoli P. Negrini M. Croce C.M. Cancer Res. 2005; 65: 7065-7070Crossref PubMed Scopus (3487) Google Scholar). Of interest, these same breast cancer suppressing miRNA candidates, miR-10b, miR-125b (along with its homolog, miR-125a), and miR-145, were also identified in a recent study as being significantly down-regulated in ERBB2-amplified and -overexpressing breast cancers clinically matched against ERBB2-negative human breast cancers (13Mattie M.D. Benz C.C. Bowers J. Sensinger K. Wong L. Scott G.K. Fedele V. Ginzinger D.G. Getts R.C. Haqq C.M. Mol. Cancer. 2006; 5: 24Crossref PubMed Scopus (630) Google Scholar). Given this involvement of miRNAs with cancer development, the manipulation of cellular miRNA levels has emerged as a potential strategy for therapeutic intervention (14Felli N. Fontana L. Pelosi E. Botta R. Bonci D. Facchiano F. Liuzzi F. Lulli V. Morsilli O. Santoro S. Valtieri M. Calin G.A. Liu C.G. Sorrentino A. Croce C.M. Peschle C. Proc. Natl. Acad. Sci. U. S. A. 2005; 102: 18081-18086Crossref PubMed Scopus (688) Google Scholar, 15Krutzfeldt J. Rajewsky N. Braich R. Rajeev K.G. Tuschl T. Manoharan M. Stoffel M. Nature. 2005; 438: 685-689Crossref PubMed Scopus (3378) Google Scholar, 16Weiler J. Hunziker J. Hall J. Gene Ther. 2006; 13: 496-502Crossref PubMed Scopus (347) Google Scholar). Efforts to predictably alter intracellular transcript profiles by increasing specific miRNA levels either through transfection or viral delivery methods have demonstrated the potential of this strategy to modulate cellular physiology (12Lim L.P. Lau N.C. Garrett-Engele P. Grimson A. Schelter J.M. Castle J. Bartel D.P. Linsley P.S. Johnson J.M. Nature. 2005; 433: 769-773Crossref PubMed Scopus (4007) Google Scholar, 14Felli N. Fontana L. Pelosi E. Botta R. Bonci D. Facchiano F. Liuzzi F. Lulli V. Morsilli O. Santoro S. Valtieri M. Calin G.A. Liu C.G. Sorrentino A. Croce C.M. Peschle C. Proc. Natl. Acad. Sci. U. S. A. 2005; 102: 18081-18086Crossref PubMed Scopus (688) Google Scholar). Conversely, attempts to reduce miRNA levels using biologically stable antisense moieties such as 2′O-methyl oligonucleotides or “antagomirs” have also proven capable of altering intracellular transcript profiles (15Krutzfeldt J. Rajewsky N. Braich R. Rajeev K.G. Tuschl T. Manoharan M. Stoffel M. Nature. 2005; 438: 685-689Crossref PubMed Scopus (3378) Google Scholar, 16Weiler J. Hunziker J. Hall J. Gene Ther. 2006; 13: 496-502Crossref PubMed Scopus (347) Google Scholar). A bioinformatics comparison of the 3′-UTRs of ERBB2 and ERBB3 revealed a consensus target element for both miR-125a and miR-125b; thus, the present study was undertaken to assess ERBB2 and ERBB3 suppression after retroviral delivery and overexpression of these miRNAs in an ERBB2-amplified and -overexpressing human breast cancer cell line, SKBR3. Overexpression of miR-125a or miR-125b reduced ERBB2 and ERBB3 at both the transcript and protein level in these leading to reduced ERK1/2 and AKT miR-125a- or miR-125b-overexpressing SKBR3 cells and anchorage-dependent growth in to reduced cell migration and invasion capacities. Parallel studies performed on MCF10A cells demonstrated that miR-125a or miR-125b overexpression produced only marginal influences on the anchorage-dependent growth and migration of these non-transformed and human mammary epithelial cells. Cell and human breast cancer cell line, and the non-transformed and human mammary epithelial cell line, were from the SKBR3 cells were in with and MCF10A cells were in with EGF and used in this study the ERBB2 from ERBB3 from to AKT and from Cell and to from and migration were using and from and of from the 5′ of miRNA of the human miRNA in the were for complementarity to the 3′-UTRs of ERBB2 and ERBB3 human miRNAs miR-125a and miR-125b with of were from human and into the were by and was into the expression used for the of miR-125a and miR-125b and miR-125b, and and retroviral were produced as G.P. K. M. J. Mol. Cell. Biol. PubMed Scopus Google Scholar). SKBR3 and MCF10A cells were with retroviral expressing miR-125b or only the retroviral infection and primary at cell of and with and were for and SKBR3 containing the 3′-UTR sequences from ERBB2 and ERBB3 were and used as for of the or and for ERBB2 and ERBB3 3′-UTR were into the of the to and containing the and 3′-UTRs from ERBB2 and 3′-UTR from all constructs were transfection were performed in with or cells using to the transfection of a were in to of the and with at three transfection performed for 3′-UTR expression was with for of transfection both the and constructs the potential from miR-125a or miR-125b overexpression were and RNA using from SKBR3 and MCF10A cells was by and G.K. M.D. Benz Benz C.C. Cancer Res. 2006; PubMed Scopus Google were used to ERBB2 and ERBB3 transcripts relative to of and expression of miR-125a and miR-125b were using with RNA as G.K. M.D. Benz Benz C.C. Cancer Res. 2006; PubMed Scopus Google and with miR-125a or miR-125b oligonucleotides that were for RNA was by with a antisense protein from SKBR3 was by using methods and G.K. C. F. L. Benz C.C. Mol. Cancer Ther. 2002; to ERBB2 and ERBB3 levels relative to and and relative to ERK1/2 and Cell and cell were in three using the cell and cells were and into of at 2 cells cell were and on and after cell migration and invasion were three using cell were and in or growth SKBR3 cells in of were to either or and in with of with as for both migration and invasion MCF10A cells are capable of migration after MCF10A cells in of were to in with of with and growth as of cells on the were with as by the on the were in for 2 by in a in were in were using an at and cell were after of and as a of the cell within the 3′-UTRs of ERBB2 and ERBB3 and Overexpression of in explore the strategy of miRNAs to the of with oncogenic the ERBB of growth and family was chosen for miRNA A bioinformatics search of ERBB family 3′-UTRs for complementarity to miRNA seed sequences from the 5′ end), as in the on miR-125a and miR-125b. 3′-UTR regions of both ERBB2 and ERBB3 were to complementarity with the 5′ of miR-125a and miR-125b. in the family was also supported by its to the identified miRNA to cellular V. Horvitz H.R. Science. PubMed Scopus Google Scholar, L. Mol. Cell. Biol. 2005; PubMed Scopus Google as as recent of this miRNA family as breast cancer (8Iorio M.V. Ferracin M. Liu C.-G. Veronese A. Spizzo R. Sabbioni S. Magri E. Pedriali M. Fabbri M. Campiglio M. Menard S. Palazzo J.P. Rosenberg A. Musiani P. Volinia S. Nenci I. Calin G.A. Querzoli P. Negrini M. Croce C.M. Cancer Res. 2005; 65: 7065-7070Crossref PubMed Scopus (3487) Google Scholar). in the between the 3′-UTR target in ERBB2 and ERBB3 and the seed sequences in miR-125a or miR-125b all at by and with miRNA targeting 2004; PubMed Scopus Google Scholar). of viral constructs the of intracellular levels of mature miRNA the miRNA To this containing miR-125a and miR-125b sequences were by from human and into a transcript levels by its A human breast cancer cell line, upon ERBB2 and overexpression for its growth and and the non-transformed and human mammary epithelial cell line, were and for viral by in the of expression of mature miR-125a and miR-125b was in both cell at their miRNA SKBR3 Overexpression of miR-125a or miR-125b ERBB2 and ERBB3 and and by ERK1/2 and AKT retroviral infection and of RNA and protein were from SKBR3 cells either miR-125a or miR-125b overexpression and from cells with the and in the of ERBB2 transcript levels in the and cells were and of levels after by mRNA ERBB3 mRNA levels in and cells were and that of levels after in the of ERBB2 protein levels were reduced to and that of levels in and whereas ERBB3 protein levels were reduced to and that of after by of ERBB2 and ERBB3 and phosphorylation of ERK1/2 and AKT the of these two were by protein from and cells relative to from cells. in the of and levels relative to ERK1/2 and AKT levels were significantly reduced in the miR-125a- and miR-125b-overexpressing SKBR3 with the suppression than the with the more pronounced ERBB2 and ERBB3 protein suppression in the cells with the cells. of ERBB2 and ERBB3 3′-UTRs for the 3′-UTRs from and for to miR-125a or miR-125b the 3′-UTR sequences from ERBB2 and ERBB3 were into the expressing using a of the to and expression for transfection into and cells. in the or constructs were suppressed by in the miR-125a- and miR-125b-expressing SKBR3 cells relative to activity in the cells. To the involvement of miR-125a and miR-125b in this 3′-UTR deletion constructs were that the from the ERBB2 and ERBB3 were to whereas were to where the and constructs for ERBB2 and ERBB3 were into and activity from was than that from whereas the activity from was than activity from as in in is the activity from the deletion constructs to their in the the levels of miR-125a and miR-125b in these cells in Overexpression of miR-125a or miR-125b of anchorage-dependent growth of miR-125a or miR-125b overexpression were in the SKBR3 and MCF10A cell were performed on cells within after their retroviral infection and and in within 2 of an of and only and of the miR-125a- and miR-125b-overexpressing and growing relative to the cells. this growth by to an growth by the and cells relative to the cells. to the impaired anchorage-dependent growth with miR-125a or miR-125b overexpression in the SKBR3 that the produced and and cells exhibited impaired and growth within the 2 relative to cells. their growth to an growth by the and cells relative to the a influence by these miRNAs on cellular of ERBB2 and to the suppressing of miR-125a and miR-125b (8Iorio M.V. Ferracin M. Liu C.-G. Veronese A. Spizzo R. Sabbioni S. Magri E. Pedriali M. Fabbri M. Campiglio M. Menard S. Palazzo J.P. Rosenberg A. Musiani P. Volinia S. Nenci I. Calin G.A. Querzoli P. Negrini M. Croce C.M. Cancer Res. 2005; 65: 7065-7070Crossref PubMed Scopus (3487) Google Scholar). Overexpression of miR-125a or miR-125b and of studies have ERBB2 and ERBB3 with cellular and R. D. D. A. Nat. Cell Biol. 2004; 6: PubMed Scopus Google Scholar, Y. M. J. Proc. Natl. Acad. Sci. U. S. A. 2004; PubMed Scopus Google a was used to the of and overexpression on cellular migration and by the and in and cells exhibited a than in their relative to cells. and as in and cells exhibited less than a in their relative to cells. both cell and through a and extracellular is to more assess cell Although and capable of with SKBR3 the non-transformed MCF10A cells are of through an extracellular Although the of SKBR3 cells be than that of other more breast cancer cell it is as are the of or overexpression on SKBR3 in and cells pronounced in their with the and the in their of cells relative to controls. retroviral overexpression of miR-125a or miR-125b in the human breast cancer cell line, produced suppression of its anchorage-dependent growth potential and of its and retroviral overexpression of these miRNAs in non-transformed and MCF10A cells produced marginal on its anchorage-dependent growth and on the of these human breast epithelial cells. in the and ERBB2-amplified SKBR3 breast cancer model and in the MCF10A breast epithelial model are with of the ERBB2 and ERBB3 transcript and protein levels in by expression of either miR-125a or miR-125b, two miRNAs that capable of targeting the target within the 3′-UTR sequences of human ERBB2 and ERBB3. in ERBB2 and ERBB3 protein levels be to miRNA on ERBB2 and ERBB3 transcript stability and as a that miR-125a and can both transcript decay and translational L. Mol. Cell. Biol. 2005; PubMed Scopus Google Scholar). Although the MCF10A cell these and cells or ERBB2 or ERBB3 and to that miR-125a and miR-125b target other growth of ERBB2 and ERBB3 be by the growth in and cells relative to cells and also the suppressing of miR-125a and miR-125b in human breast cancers of ERBB2 (8Iorio M.V. Ferracin M. Liu C.-G. Veronese A. Spizzo R. Sabbioni S. Magri E. Pedriali M. Fabbri M. Campiglio M. Menard S. Palazzo J.P. Rosenberg A. Musiani P. Volinia S. Nenci I. Calin G.A. Querzoli P. Negrini M. Croce C.M. Cancer Res. 2005; 65: 7065-7070Crossref PubMed Scopus (3487) Google Scholar). Although only a ERBB in such a C. and are ERBB in capable of or by epithelial cell growth and a of intracellular used for epithelial cell development, and Y. Nat. Rev. Mol. Cell Biol. PubMed Scopus Google Scholar). of three of these or in can of all human breast cancers are with and overexpression of and the of such breast cancers are on both of ERBB2 as as their with either or ERBB3 are to be for the growth and potential of human breast cancers, it is the ERBB3 of ERBB2 that can up to and intracellular phosphorylation of and cell and invasion of this of human breast cancer R. D. D. A. Nat. Cell Biol. 2004; 6: PubMed Scopus Google Scholar, Y. M. J. Proc. Natl. Acad. Sci. U. S. A. 2004; PubMed Scopus Google Scholar, T. F. M. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar). as the suppression of both ERBB2 and ERBB3 expression in an breast cancer cell line be to significantly levels and only its potential also its and the of ERBB2 in human breast are that target of the ERBB family J. Science. 2006; PubMed Scopus Google an of ERBB2 and and an of and Although exist capable of targeting the of both and are as specific of the or of ERBB3. of a search ERBB family identified a within the 3′-UTRs of both ERBB2 and ERBB3. for the between the 3′-UTR target in ERBB2 and ERBB3 and the seed sequences in miR-125a or miR-125b are with miRNA targeting 2004; PubMed Scopus Google Scholar). from identifying a targeting element in both ERBB2 and also identified regions in the 3′-UTRs of ERBB2 and ERBB3. 3′-UTR regions have been in other genes to be for the of transcript S. S. T. A. J. F. H. J. Cell. 2005; 120: Full Text Full Text PDF PubMed Scopus Google Scholar). Luciferase constructs containing the 3′-UTRs of ERBB2 and ERBB3 demonstrated significantly less activity in miR-125a- and miR-125b-overexpressing SKBR3 cells relative to controls. To that the 3′-UTR containing the miR-125a and miR-125b targeting mediated this deletion constructs these targeting were and into and cells. These deletion demonstrated of the by the ERBB2 and ERBB3 only in the of miR-125a or miR-125b whereas identifying the element as for this these deletion constructs to regions within the 3′-UTRs of ERBB2 and ERBB3 containing the targeting oncogenic ERBB2 and ERBB3 overexpression in a model breast cancer cell line SKBR3 by expression of miR-125a and miR-125b the potential of and miRNA delivery by to cancer cell as a therapeutic delivery of miRNAs by viral or other be against their potential to cellular by for miRNA such to nuclear by and the Dicer and RISC of by RNA has been to activity Y. J. Biol. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar). in delivery and viral expression of RNAs has produced in with of miRNAs that also for D. K. P. F. Nature. 2006; PubMed Scopus Google Scholar). with the of ERBB2 and ERBB3 levels mediated by overexpression of miR-125a and miR-125b, influences on such of the cell as and were also have been identified that alter cancer by intracellular miRNA profiles G.K. M.D. Benz Benz C.C. Cancer Res. 2006; PubMed Scopus Google Scholar). Although delivery of a miRNA can a it has been that miRNA regulation of a transcript is miRNAs in (1Bartel D.P. Cell. 2004; 116: 281-297Abstract Full Text Full Text PDF PubMed Scopus (29622) Google Scholar, 2Ambros V. Nature. 2004; 431: 350-355Crossref PubMed Scopus (9088) Google Scholar, 3Zamore P.D. Haley B. Science. 2005; 309: 1519-1524Crossref PubMed Scopus (1130) Google Scholar). such recent as the delivery of miRNAs from a C.C. S. A. J. P.D. Res. 2006; PubMed Scopus Google delivery of and targeted miRNAs are to only the of miRNAs as research also further for the of that modulate miRNA