Anti-microRNA-222 (anti-miR-222) and -181B suppress growth of tamoxifen-resistant xenografts in mouse by targeting TIMP3 protein and modulating mitogenic signal.
We have shown earlier that miR-221 and -222 are up-regulated in tamoxifen-resistant MCF-7 (OHT(R)) cells and Her2-positive human breast tumors when compared with Her2 negative tumors. In this study, we report markedly enhanced expression of miR-181b in OHT(R) cells and endocrine-resistant tumors. Further, anti-miR-222 or -181b in combination with tamoxifen suppressed growth of tamoxifen-resistant xenografts in mice. Luciferase reporter assay and expression analysis showed that TIMP3, a tissue metalloproteinase inhibitor, is a common target of miR-221/222 and -181b. In situ hybridization and immunohistochemical analysis demonstrated reciprocal relationships between TIMP3 and miR-221/222/181b expression in primary human breast carcinomas. Ectopic expression of TIMP3 inhibited growth of the OHT(R) cells, and its depletion in MCF-7 cells reduced sensitivity to tamoxifen in vitro and in vivo. EGF-induced MAPK and AKT phosphorylation were significantly higher in OHT(R) cells and miR-221/222-overexpressing MCF-7 cells than in control cells, which suggests modulation of mitogenic signaling by TIMP3 and the miRs. On the contrary, phosphoMAPK and phosphoAKT levels were diminished in TIMP3-overexpressing OHT(R) cells and increased in TIMP3-depleted MCF-7 cells. Low levels of estrogen or tamoxifen elicited similar differences in phosphoMAPK levels in these cells. Reduced levels of TIMP3 facilitated growth of tamoxifen-resistant cells by alleviating its inhibitory effect on ADAM10 and ADAM17, which are critical for OHT(R) cell growth. In conclusion, miR-221/222 and -181b facilitate growth factor signaling in tamoxifen-resistant breast cancer by down-regulating TIMP3, and corresponding anti-miRs can be used to render these tumors responsive to tamoxifen.
Departments of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210; Department of Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210.
Yuanzhi
Y
Lu
Departments of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210.
Satavisha
S
Roy
Department of Pathology, The Ohio State University, Columbus, Ohio 43210.
Gerard
G
Nuovo
Department of Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210; Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210.
Bhuvaneswari
B
Ramaswamy
Departments of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210.
Tyler
T
Miller
Department of Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210; Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210.
Charles
C
Shapiro
Departments of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210; Department of Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210; Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210. Electronic address: Samson.Jacob@osumc.edu.
Samson T
ST
Jacob
Departments of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210; Department of Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210. Electronic address: Sarmila.majumder@osumc.edu.
Sarmila
S
Majumder
D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D015674:Mammary Neoplasms, Animal / Q000235:genetics / Q000378:metabolism*; D045726:Metalloproteases / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D009368:Neoplasm Transplantation; D013629:Tamoxifen / Q000494:pharmacology*; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000502:physiology*; D014945:Wound Healing
D018931:Antineoplastic Agents, Hormonal; D036341:Intercellular Signaling Peptides and Proteins; D045726:Metalloproteases; D035683:MicroRNAs; D013629:Tamoxifen; D019717:Tissue Inhibitor of Metalloproteinase-3; C525710:MIR222, human; C546123:MIRN222 microRNA, mouse; C540193:MIrn181 microRNA, human; C529100:mirn181 microRNA, mouse