Long noncoding RNA cancer susceptibility candidate 9 promotes doxorubicin‑resistant breast cancer by binding to enhancer of zeste homolog 2

Jiang,Baohong; Li,Yuehua; Qu,Xiaofei; Zhu,Hongbo; Tan,Yeru; Fan,Qun; Jiang,Yiling; Liao,Mingchu; Wu,Xiaoping

doi:10.3892/ijmm.2018.3812

Long noncoding RNA cancer susceptibility candidate 9 promotes doxorubicin‑resistant breast cancer by binding to enhancer of zeste homolog 2

Authors:
- Baohong Jiang
- Yuehua Li
- Xiaofei Qu
- Hongbo Zhu
- Yeru Tan
- Qun Fan
- Yiling Jiang
- Mingchu Liao
- Xiaoping Wu
View Affiliations

Affiliations: Department of Pharmacy, The First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, P.R. China, Department of Medical Oncology, The First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, P.R. China
Published online on: August 7, 2018 https://doi.org/10.3892/ijmm.2018.3812
Pages: 2801-2810

Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )

Metrics: Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )

Cited By (CrossRef): 0 citations Loading Articles...

Abstract

The present study aimed to investigate the effect of the long noncoding RNA cancer susceptibility candidate 9 (CASC9) on doxorubicin (DOX)‑resistant breast cancer and to reveal the potential underlying mechanisms. The expression of CASC9 in breast cancer tissues and cell lines, in addition to drug‑resistant breast cancer cells (MCF‑7/DOX), was detected by reverse transcription‑quantitative polymerase chain reaction. Subsequently, MCF‑7/DOX cells were transfected with the silencing vector pS‑CASC9, containing enhancer of zeste homolog 2 (EZH2), multidrug resistance protein 1 (MDR1) or control small interfering (si)RNAs. The viability, apoptosis, migration and invasion of the transfected cells were assessed via an MTT assay, flow cytometry and a Transwell assay, respectively. The expression levels of apoptosis‑associated proteins (apoptosis regulator Bcl‑2, apoptosis regulator BAX, caspase‑3 and caspase‑9) were determined by western blotting. An RNA pull‑down assay was performed to identify CASC9‑binding candidates. In addition, the expression levels of the MDR1 gene and its encoded protein, P‑glycoprotein, were detected. CASC9 expression was upregulated in breast cancer tissues and cell lines, and drug‑resistant breast cancer cells. CASC9 knockdown significantly inhibited the growth and metastasis of drug‑resistant breast cancer cells, and decreased the half‑maximal inhibitory concentration DOX in MCF‑7/DOX cells. The RNA pull‑down assay revealed that CASC9 engaged EZH2; EZH2 siRNA significantly inhibited the cell growth, metastasis and chemoresistance of MCF‑7/DOX cells. Additionally, EZH2 may regulate the MDR1 gene. The present study demonstrated the oncogenic role of CASC9 in drug‑resistant breast cancer by binding to EZH2 and regulating the MDR1 gene. Modulation of CASC9 expression may be a promising target in the therapy of breast cancer and drug‑resistant breast cancer.

View Figures

View References

1	Ferlay J, Héry C, Autier P and Sankaranarayanan R: Global burden of breast cancer. Breast cancer epidemiology. Springer; pp. 1–19. 2010
2	Riaz M, van Jaarsveld MT, Hollestelle A, Prager-van der Smissen WJ, Heine AA, Boersma AW, Liu J, Helmijr J, Ozturk B, Smid M, et al: miRNA expression profiling of 51 human breast cancer cell lines reveals subtype and driver mutation-specific miRNAs. Breast Cancer Res. 15:R332013. View Article : Google Scholar : PubMed/NCBI
3	World Health Organization: World Cancer Report. 2014
4	Eifel P, Axelson JA, Costa J, Crowley J, Curran WJ Jr, Deshler A, Fulton S, Hendricks CB, Kemeny M, Kornblith AB, et al: National institutes of health consensus development conference statement: Adjuvant therapy for breast cancer, november 1-3, 2000. J Natl Cancer Inst. 93:979–989. 2001. View Article : Google Scholar : PubMed/NCBI
5	Blum RH and Carter SK: Adriamycin. A new anticancer drug with significant clinical activity. Ann Intern Med. 80:249–259. 1974. View Article : Google Scholar : PubMed/NCBI
6	Chen JS, Agarwal N and Mehta K: Multidrug-resistant MCF-7 breast cancer cells contain deficient intracellular calcium pools. Breast Cancer Res Treat. 71:237–247. 2002. View Article : Google Scholar : PubMed/NCBI
7	Herman J, Mangala L and Mehta K: Implications of increased tissue transglutaminase (TG2) expression in drug-resistant breast cancer (MCF-7) cells. Oncogene. 25:3049–3058. 2006. View Article : Google Scholar : PubMed/NCBI
8	Roberti A, La Sala DL and Cinti C: Multiple genetic and epigenetic interacting mechanisms contribute to clonally selection of drug-resistant tumors: Current views and new therapeutic prospective. J Cell Physiol. 207:571–581. 2006. View Article : Google Scholar
9	Duesberg P, Li R, Sachs R, Fabarius A, Upender MB and Hehlmann R: Cancer drug resistance: The central role of the karyotype. Drug Resist Updat. 10:51–58. 2007. View Article : Google Scholar : PubMed/NCBI
10	Fojo T: Multiple paths to a drug resistance phenotype: Mutations, translocations, deletions and amplification of coding genes or promoter regions, epigenetic changes and microRNAs. Drug Resist Updat. 10:59–67. 2007. View Article : Google Scholar : PubMed/NCBI
11	Sevignani C, Calin GA, Siracusa LD and Croce CM: Mammalian microRNAs: A small world for fine-tuning gene expression. Mamm Genome. 17:189–202. 2006. View Article : Google Scholar : PubMed/NCBI
12	Bushati N and Cohen SM: microRNA functions. Annu Rev Cell Dev Biol. 23:175–205. 2007. View Article : Google Scholar : PubMed/NCBI
13	Spizzo R, Almeida MIE, Colombatti A and Calin GA: Long non-coding RNAs and cancer: A new frontier of translational research? Oncogene. 31:4577–4587. 2012. View Article : Google Scholar : PubMed/NCBI
14	Gibb EA, Brown CJ and Lam WL: The functional role of long non-coding RNA in human carcinomas. Mol Cancer. 10:382011. View Article : Google Scholar : PubMed/NCBI
15	Shore AN, Herschkowitz JI and Rosen JM: Noncoding RNAs involved in mammary gland development and tumorigenesis: There's a long way to go. J Mammary Gland Biol Neoplasia. 17:43–58. 2012. View Article : Google Scholar : PubMed/NCBI
16	Pan Z, Mao W, Bao Y, Zhang M, Su X and Xu X: The long noncoding RNA CASC9 regulates migration and invasion in esophageal cancer. Cancer Med. 5:2442–2447. 2016. View Article : Google Scholar : PubMed/NCBI
17	Song P, Jiang B, Liu Z, Ding J, Liu S and Guan W: A three-lncRNA expression signature associated with the prognosis of gastric cancer patients. Cancer Med. 6:1154–1164. 2017. View Article : Google Scholar : PubMed/NCBI
18	Su X, Li G and Liu W: The long noncoding RNA cancer susceptibility candidate 9 promotes nasopharyngeal carcinogenesis via stabilizing HIF1α. DNA Cell Biol. 36:394–400. 2017. View Article : Google Scholar : PubMed/NCBI
19	Chekhun VF, Lukyanova NY, Kovalchuk O, Tryndyak VP and Pogribny IP: Epigenetic profiling of multidrug-resistant human MCF-7 breast adenocarcinoma cells reveals novel hyper- and hypomethylated targets. Mol Cancer Ther. 6:1089–1098. 2007. View Article : Google Scholar : PubMed/NCBI
20	Livak KJ and Schmittgen TD: Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) method. Methods. 25:402–408. 2001. View Article : Google Scholar
21	Kleer CG, Cao Q, Varambally S, Shen R, Ota I, Tomlins SA, Ghosh D, Sewalt RG, Otte AP, Hayes DF, et al: EZH2 is a marker of aggressive breast cancer and promotes neoplastic transformation of breast epithelial cells. Proc Natl Acad Sci USA. 100:11606–11611. 2003. View Article : Google Scholar : PubMed/NCBI
22	Hoffmeyer S, Burk O, Von Richter O, Arnold HP, Brockmöller J, Johne A, Cascorbi I, Gerloff T, Roots I, Eichelbaum M, et al: Functional polymorphisms of the human multidrug-resistance gene: Multiple sequence variations and correlation of one allele with P-glycoprotein expression and activity in vivo. Proc Natl Acad Sci USA. 97:3473–3478. 2000. View Article : Google Scholar : PubMed/NCBI
23	Tang B, Zhang Y, Liang R, Gao Z, Sun D and Wang L: RNAi-mediated EZH2 depletion decreases MDR1 expression and sensitizes multidrug-resistant hepatocellular carcinoma cells to chemotherapy. Oncol Rep. 29:1037–1042. 2013. View Article : Google Scholar : PubMed/NCBI
24	Zhou W, Wang J, Man WY, Zhang QW and Xu WG: siRNA silencing EZH2 reverses cisplatin-resistance of human non-small cell lung and gastric cancer cells. Asian Pac J Cancer Prev. 16:2425–2430. 2015. View Article : Google Scholar : PubMed/NCBI
25	Zhang Y, Liu G, Lin C, Liao G and Tang B: Silencing the EZH2 gene by RNA interference reverses the drug resistance of human hepatic multidrug-resistant cancer cells to 5-Fu. Life Sci. 92:896–902. 2013. View Article : Google Scholar : PubMed/NCBI
26	Cao W, Wu W, Shi F, Chen X, Wu L, Yang K, Tian F, Zhu M, Chen G, Wang W, et al: Integrated analysis of long noncoding RNA and coding RNA expression in esophageal squamous cell carcinoma. Int J Genomics. 2013:4805342013. View Article : Google Scholar : PubMed/NCBI
27	Shang C, Sun L, Zhang J, Zhao B, Chen X, Xu H and Huang B: Silence of cancer susceptibility candidate 9 inhibits gastric cancer and reverses chemoresistance. Oncotarget. 8:15393–15398. 2017. View Article : Google Scholar : PubMed/NCBI
28	Visser HP, Gunster MJ, Kluin-Nelemans HC, Manders EM, Raaphorst FM, Meijer CJ, Willemze R and Otte AP: The Polycomb group protein EZH2 is upregulated in proliferating, cultured human mantle cell lymphoma. Br J Haematol. 112:950–958. 2001. View Article : Google Scholar : PubMed/NCBI
29	Varambally S, Dhanasekaran SM, Zhou M, Barrette TR, Kumar-Sinha C, Sanda MG, Ghosh D, Pienta KJ, Sewalt RG, Otte AP, et al: The polycomb group protein EZH2 is involved in progression of prostate cancer. Nature. 419:624–629. 2002. View Article : Google Scholar : PubMed/NCBI
30	Raman JD, Mongan NP, Tickoo SK, Boorjian SA, Scherr DS and Gudas LJ: Increased expression of the polycomb group gene, EZH2, in transitional cell carcinoma of the bladder. Clin Cancer Res. 11:8570–8576. 2005. View Article : Google Scholar : PubMed/NCBI
31	Collett K, Eide GE, Arnes J, Stefansson IM, Eide J, Braaten A, Aas T, Otte AP and Akslen LA: Expression of enhancer of zeste homologue 2 is significantly associated with increased tumor cell proliferation and is a marker of aggressive breast cancer. Clin Cancer Res. 12:1168–1174. 2006. View Article : Google Scholar : PubMed/NCBI
32	Callaghan R, Luk F and Bebawy M: Inhibition of the multidrug resistance P-glycoprotein: Time for a change of strategy? Drug Metab Dispos. 42:623–631. 2014. View Article : Google Scholar : PubMed/NCBI
33	Rahbari NN, Mehrabi A, Mollberg NM, Müller SA, Koch M, Büchler MW and Weitz J: Hepatocellular carcinoma: Current management and perspectives for the future. Ann Surg. 253:453–469. 2011. View Article : Google Scholar : PubMed/NCBI
34	Takara K, Sakaeda T and Okumura K: An update on overcoming MDR1-mediated multidrug resistance in cancer chemotherapy. Curr Pharm Des. 12:273–286. 2006. View Article : Google Scholar : PubMed/NCBI