Department of Breast Surgery,Affiliated Tumor Hospital of Zhengzhou University,Zhengzhou 450000,China (Yuan P,Wang CZ,Xu BL,Qin P,Wu JZ,Xie T,Qin L);Central Laboratory,Affiliated Tumor Hospital of Zhengzhou University,Zhengzhou 450000,China (Yang HZ,Sun H);Department of Breast Radiotherapy,Affiliated Tumor Hospital of Zhengzhou University,Zhengzhou 450000,China (Liu X)
Objective To study the individual and combined effects of HER-2 and TOP2A on the radiosensitivity of breast cancer SK-Br-3 cells, and to provide a basis for clinical research. Methods To knock down the expression of HER-2 and TOP2A, the recombinant plasmids expressing HER-2 siRNA or/and TOP2A siRNA were constructed and used to transfect SK-Br-3 cells using Lipofectamine 2000. Western blot was used to evaluate the knockdown efficiency two days later. Flow cytometry and MTT assay were used to evaluate apoptosis and proliferation in cells exposed to radiation, respectively. The expression of apoptosis-and proliferation-related proteins, consisting of caspase-3, Bcl-2, and Ki-67, was determined. The colony-formation assay was used to measure radiosensitivity. Results The breast cancer SK-Br-3 cells with HER-2 or TOP2A knockdown had a higher apoptosis rate and a lower proliferation rate after exposure to radiation. The apoptotic marker, activated caspase-3, had elevated expression, while the anti-apoptotic protein Bcl-2 and the proliferation marker Ki-67 had reduced expression. Knockdown of both HER-2 and TOP2A further promoted apoptosis and inhibited proliferation and colony formation, indicating a synergistic effect of HER-2 and TOP2A. Conclusions Knockdown of HER-2 and TOP2A expression elevates the radiosensitivity and apoptosis rate, and reduces the proliferation rate and colony-formation rate in the breast cancer SK-Br-3 cells. Moreover, there is a synergistic effect between HER-2 and TOP2A. The mechanism is probably related to the proliferation-related protein Ki-67 and the apoptosis pathway involving caspase-3 and Bcl-2.
Yuan Peng,Wang Chengzheng,Xu Benling et al. Enhancement of breast cancer cell radiosensitivity by knockdown of HER-2 and TOP2A[J]. Chinese Journal of Radiation Oncology, 2016, 25(6): 652-656.
[1] Siegel RL,Miller KD,Jemal A.Cancer statistics,2015[J].CA:Cancer J Clin,2015,65(1):5-29.DOI:10.3322/caac.21254. [2] Yan M,Parker BA,Schwab R,et al. HER2 aberrations in cancer:implications for therapy[J].Cancer Treat Rev,2014,40(6):770-780.DOI:10.1016/j.ctrv.2014.02.008. [3] Gianni L,Pienkowski T,Im YH,et al. Efficacy and safety of neoadjuvant pertuzumab and trastuzumab in women with locally advanced,inflammatory,or early HER2-positive breast cancer (NeoSphere):a randomised multicentre,open-label,phase 2 trial[J].Lancet Oncol,2012,13(1):25-32.DOI:10.1016/S1470-2045(11)70336-9. [4] 韦思羽,冯震博.HER-2基因在乳腺癌研究的进展[J].当代医学,2010,16(15):14-15.DOI:10.3969/j.issn.1009-4393.2010.15.008. Wei SY,Feng ZHB.The progress of HER-2 gene in breast cancer research[J].Contemp Med, 2010,16(15):14-15.DOI:10.3969/j.issn.1009-4393.2010.15.008. [5] 孟辉,李文才,王留兴,等.拓扑异构酶Ⅱα表达与乳腺癌患者生存的相关性[J].中华肿瘤杂志,2011,33(5):363-366.DOI:10.3760/cma.j.issn.0253-3766.2011.05.012. Meng H,Li WC,Wang LX,et al. Correlation of TOP2 A gene expression and survival of breast cancer patients[J].Chin J Oncol,2011,33(5):363-366.DOI:10.3760/cma.j.issn.0253-3766.2011.05.012. [6] 赵向前,梁斌,张安红,等.壶腹癌中Ki-67和TopoⅡα的表达及意义[J].中华临床医师杂志,2015,9(2):214-217.DOI:10.3877/cma.j.issn.1674-0785.2015.02.008. Zhao XQ,Liang B,Zhang AH,et al. Expression and significance of Ki-67,TopoisomeraseⅡα in ampullary carcinoma[J].Chin J Clinicians,2015,9(2):214-217.DOI:10.3877/cma.j.issn.1674-0785.2015.02.008. [7] Kallioniemi OP,Kallioniemi A,Kurisu W,et al. ERBB2 amplification in breast cancer analyzed by fluorescence in situ hybridization[J].Proc Natl Acad Sci U S A,1992,89(12):5321-5325.DOI:10.1073/pnas.89.12.5321. [8] No M,Choi EJ,Kim IA.Targeting HER2 signaling pathway for radiosensitization:alternative strategy for therapeutic resistance[J].Cancer Biol Ther,2009,8(24):2351-2361.DOI:10.4161/cbt.8.24.10131 [9] Tai WY,Mahato R,Cheng K.The role of HER2 in cancer therapy and targeted drug delivery[J].J Controlled Release,2010,146(3):264-275.DOI:10.1016/j.jconrel.2010.04.009. [10] Crosier M,Scott D,Wilson RG,et al. Differences in Ki67 and c-erbB2 expression between screen-detected and true interval breast cancers[J].Clin Cancer Res,1999,5(10):2682-2688. [11] Engelsen IB,Stefansson IM,Beroukhim R,et al. HER-2/neu expression is associated with high tumor cell proliferation and aggressive phenotype in a population based patient series of endometrial carcinomas[J].Int J Oncol,2008,32(2):307-316.DOI:10.3892/ijo.32.2.307. [12] Varis A,Wolf M,Monni O,et al. Targets of gene amplification and overexpression at 17q in gastric cancer[J].Cancer Res,2002,62(9):2625-2629. [13] Panvichian R,Tantiwetrueangdet A,Angkathunyakul N,et al. TOP2A amplification and overexpression in hepatocellular carcinoma tissues[J].BioMed Res Int,2015,2015:381602.DOI:10.1155/2015/381602. [14] Jain M,Zhang LS,He M,et al. TOP2A is overexpressed and is a therapeutic target for adrenocortical carcinoma[J].Endocr Relat Cancer,2013,20(3):361-370.DOI:10.1530/ERC-12-0403. [15] Arriola E,Marchio C,Tan D S,et al. Genomic analysis of the HER2/TOP2A amplicon in breast cancer and breast cancer cell lines[J].Lab Invest,2008,88(5):491-503.DOI:10.1038/labinvest.2008.19. [16] Simon R,Atefy R,Wagner U,et al. HER-2 and TOP2A coamplification in urinary bladder cancer[J].Int J Cancer,2003,107(5):764-772.DOI:10.1002/ijc.11477. [17] Engstrm MJ,Ytterhus B,Vatten LJ,et al. TOP2A gene copy number change in breast cancer[J].J Clin Pathol,2014,67(5):420-425.DOI:10.1136/jclinpath-2013-202052. [18] Rdel C,Grabenbauer G,Papadopoulos T,et al. Apoptosis as a cellular predictor for histopathologic response to neoadjuvant radiochemotherapy in patients with rectal cancer[J].Int J Radiat Oncol Biol Phys,2002,52(2):294-303.DOI:10.1016/S0360-3016(01)02643-8. [19] Boulakia CA,Chen G,Ng FW,et al. Bcl-2 and adenovirus E1B 19 kDA protein prevent E1A-induced processing of CPP32 and cleavage of poly (ADP-ribose) polymerase[J].Oncogene,1996,12(3):529-535. [20] Czabotar PE,Lessene G,Strasser A,et al. Control of apoptosis by the BCL-2 protein family:implications for physiology and therapy[J].Nat Rev Mol Cell Biol,2014,15(1):49-63.DOI:10.1038/nrm3722. [21] Siddiqa A,Long LM,Li LX,et al. Expression of HER-2 in MCF-7 breast cancer cells modulates anti-apoptotic proteins Survivin and Bcl-2 via the extracellular signal-related kinase (ERK) and phosphoinositide-3 kinase (PI3K) signalling pathways[J].BMC Cancer,2008,8(1):129.DOI:10.1186/1471-2407-8-129. [22] 徐恩伟,王跃华,王晋芬.乳腺癌拓扑异构酶Ⅱα基因HER-2基因及Ki-67的关系研究[J].中国药物与临床,2012,12(11):1392-1394. Xu EW,Wang YH,Wang JF.Topoisomerase Ⅱα gene HER-2 gene and Ki-67 in breast cancer:a correlation study[J].Chin Remedies Clin,2012,12(11):1392-1394. [23] Faltus T,Yuan J,Zimmer B,et al. Silencing of the HER2/neu gene by siRNA inhibits proliferation and induces apoptosis in HER2/neu-overexpressing breast cancer cells[J].Neoplasia,2004,6(6):786-795.DOI:10.1593/neo.04313.
2016, Vol. 25 
