Abstract
P50-associated cyclooxygenase-2 (COX-2) extragenic RNA (PACER) is a novel long noncoding RNA that has been found to activate the COX-2 gene, which may function as an oncogene in osteosarcoma. However, the role of PACER and the relationship between PACER and COX-2 in osteosarcoma progression have been unknown until now. Here, we examined the expression levels of PACER in clinical tumor samples and human osteosarcoma cell lines, assessed the functions of PACER in osteosarcoma cell proliferation and invasion, and then explored the mechanism of PACER dysregulation in osteosarcoma. The results showed that PACER was overexpressed in osteosarcoma tissues and cell lines compared with normal tissues and osteoblasts, respectively. PACER knockdown inhibited the proliferation and invasion of human osteosarcoma cells. Downregulation of PACER significantly suppressed the expression of COX-2, and the effects of PACER on cell proliferation and invasion were rescued by COX-2 overexpression. Furthermore, COX-2 activation by PACER was NF-κB-dependent. The regulation of PACER by CCCTC-binding factor (CTCF) was associated with DNA methylation status. Taken together, these findings suggest that PACER promotes proliferation and metastasis of osteosarcoma cells by activating the COX-2 gene and its own expression was influenced by DNA methylation.
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References
Gabory A, Jammes H, Dandolo L. The H19 locus: role of an imprinted non-coding RNA in growth and development. Bioessays. 2010;32(6):473–80.
Gutschner T, Hammerle M, Diederichs S. MALAT1—a paradigm for long noncoding RNA function in cancer. J Mol Med (Berl). 2013;91(7):791–801.
Tripathi V, Ellis JD, Shen Z, Song DY, Pan Q, Watt AT, et al. The nuclear-retained noncoding RNA MALAT1 regulates alternative splicing by modulating SR splicing factor phosphorylation. Mol Cell. 2010;39(6):925–38.
Zhang X, Lian Z, Padden C, Gerstein MB, Rozowsky J, Snyder M, et al. A myelopoiesis-associated regulatory intergenic noncoding RNA transcript within the human HOXA cluster. Blood. 2009;113(11):2526–34.
Yang G, Lu X, Yuan L. LncRNA: a link between RNA and cancer. Biochim Biophys Acta. 2014;1839(11):1097–109.
Clark JC, Dass CR, Choong PF. A review of clinical and molecular prognostic factors in osteosarcoma. J Cancer Res Clin Oncol. 2008;134(3):281–97.
Dong Y, Liang G, Yuan B, Yang C, Gao R, Zhou X. MALAT1 promotes the proliferation and metastasis of osteosarcoma cells by activating the PI3K/Akt pathway. Tumour Biol. 2015;36(3):1477–86.
Zhang Q, Geng PL, Yin P, Wang XL, Jia JP, Yao J. Down-regulation of long non-coding RNA TUG1 inhibits osteosarcoma cell proliferation and promotes apoptosis. Asian Pac J Cancer Prev. 2013;14(4):2311–5.
Wang B, Su Y, Yang Q, Lv D, Zhang W, Tang K, et al. Overexpression of long non-coding RNA HOTAIR promotes tumor growth and metastasis in human osteosarcoma. Mol Cells. 2015;38:5.
Krawczyk M, Emerson BM. p50-associated COX-2 extragenic RNA (PACER) activates COX-2 gene expression by occluding repressive NF-kappaB complexes. Elife. 2014;3:e01776.
Smith WL, Garavito RM, DeWitt DL. Prostaglandin endoperoxide H synthases (cyclooxygenases)-1 and -2. J Biol Chem. 1996;271(52):33157–60.
Nzeako UC, Gores GJ. Increased expression of cyclooxygenase-2 in human pancreatic neoplasms and potential for chemoprevention by cyclooxygenase inhibitors. Cancer. 2002;94(6):1903–4.
Tsujii M, Kawano S, DuBois RN. Cyclooxygenase-2 expression in human colon cancer cells increases metastatic potential. Proc Natl Acad Sci U S A. 1997;94(7):3336–40.
Wang Z, He M, Xiao Z, Wu H, Wu Y. Quantitative assessment of the association of COX-2 (cyclooxygenase-2) immunoexpression with prognosis in human osteosarcoma: a meta-analysis. PLoS One. 2013;8(12):e82907.
Jiao G, Ren T, Lu Q, Sun Y, Lou Z, Peng X, et al. Prognostic significance of cyclooxygenase-2 in osteosarcoma: a meta-analysis. Tumour Biol. 2013;34(5):2489–95.
Lee EJ, Choi EM, Kim SR, Park JH, Kim H, Ha KS, et al. Cyclooxygenase-2 promotes cell proliferation, migration and invasion in U2OS human osteosarcoma cells. Exp Mol Med. 2007;39(4):469–76.
Zhao Q, Wang C, Zhu J, Wang L, Dong S, Zhang G, et al. RNAi-mediated knockdown of cyclooxygenase2 inhibits the growth, invasion and migration of SaOS2 human osteosarcoma cells: a case control study. J Exp Clin Cancer Res. 2011;30:26.
Naruse T, Nishida Y, Hosono K, Ishiguro N. Meloxicam inhibits osteosarcoma growth, invasiveness and metastasis by COX-2-dependent and independent routes. Carcinogenesis. 2006;27(3):584–92.
Zhang H, Zhu L, He H, Zhu S, Zhang W, Liu X, et al. NF-kappa B mediated up-regulation of CCCTC-binding factor in pediatric acute lymphoblastic leukemia. Mol Cancer. 2014;13:5.
Fiorentino FP, Giordano A. The tumor suppressor role of CTCF. J Cell Physiol. 2012;227(2):479–92.
Kang JY, Song SH, Yun J, Jeon MS, Kim HP, Han SW, et al. Disruption of CTCF/cohesin-mediated high-order chromatin structures by DNA methylation downregulates PTGS2 expression. Oncogene. 2015
Appleby SB, Ristimaki A, Neilson K, Narko K, Hla T. Structure of the human cyclo-oxygenase-2 gene. Biochem J. 1994;302(3):723–7.
Shukla S, Kavak E, Gregory M, Imashimizu M, Shutinoski B, Kashlev M, et al. CTCF-promoted RNA polymerase II pausing links DNA methylation to splicing. Nature. 2011;479(7371):74–9.
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Ming Qian and Xinghai Yang contributed equally to this work.
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Qian, M., Yang, X., Li, Z. et al. P50-associated COX-2 extragenic RNA (PACER) overexpression promotes proliferation and metastasis of osteosarcoma cells by activating COX-2 gene. Tumor Biol. 37, 3879–3886 (2016). https://doi.org/10.1007/s13277-015-3838-8
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DOI: https://doi.org/10.1007/s13277-015-3838-8