PRC2/EED-EZH2 Complex is Up-regulated in Breast Cancer Lymph Node Metastasis Compared to Primary Tumor and Correlates with Tumor Proliferation in Situ

Overview

Journal PLoS One

Specialties General Medicine
Science

Date 2012 Dec 20

PMID 23251464

Citations 28

Authors

Hongxiang Yu

Diana L Simons

Ilana Segall

Valeria Carcamo-Cavazos

Erich J Schwartz

Ning Yan

Neta S Zuckerman

Frederick M Dirbas

Denise L Johnson

Susan P Holmes

Peter P Lee

Affiliations

Soon will be listed here.

Abstract

Background: Lymph node metastasis is a key event in the progression of breast cancer. Therefore it is important to understand the underlying mechanisms which facilitate regional lymph node metastatic progression.

Methodology/principal Findings: We performed gene expression profiling of purified tumor cells from human breast tumor and lymph node metastasis. By microarray network analysis, we found an increased expression of polycomb repression complex 2 (PRC2) core subunits EED and EZH2 in lymph node metastatic tumor cells over primary tumor cells which were validated through real-time PCR. Additionally, immunohistochemical (IHC) staining and quantitative image analysis of whole tissue sections showed a significant increase of EZH2 expressing tumor cells in lymph nodes over paired primary breast tumors, which strongly correlated with tumor cell proliferation in situ. We further explored the mechanisms of PRC2 gene up-regulation in metastatic tumor cells and found up-regulation of E2F genes, MYC targets and down-regulation of tumor suppressor gene E-cadherin targets in lymph node metastasis through GSEA analyses. Using IHC, the expression of potential EZH2 target, E-cadherin was examined in paired primary/lymph node samples and was found to be significantly decreased in lymph node metastases over paired primary tumors.

Conclusions/significance: This study identified an over expression of the epigenetic silencing complex PRC2/EED-EZH2 in breast cancer lymph node metastasis as compared to primary tumor and its positive association with tumor cell proliferation in situ. Concurrently, PRC2 target protein E-cadherin was significant decreased in lymph node metastases, suggesting PRC2 promotes epithelial mesenchymal transition (EMT) in lymph node metastatic process through repression of E-cadherin. These results indicate that epigenetic regulation mediated by PRC2 proteins may provide additional advantage for the outgrowth of metastatic tumor cells in lymph nodes. This opens up epigenetic drug development possibilities for the treatment and prevention of lymph node metastasis in breast cancer.

Citing Articles

Polycomb repressive complex 2 (PRC2) pathway's role in cancer cell plasticity and drug resistance.

Goleij P, Heidari M, Tabari M, Hadipour M, Rezaee A, Javan A Funct Integr Genomics. 2025; 25(1):53.

PMID: 40048009 DOI: 10.1007/s10142-025-01563-8.

Focal adhesion in the tumour metastasis: from molecular mechanisms to therapeutic targets.

Liu Z, Zhang X, Ben T, Li M, Jin Y, Wang T Biomark Res. 2025; 13(1):38.

PMID: 40045379 PMC: 11884212. DOI: 10.1186/s40364-025-00745-7.

Regulation of histone H3K27 methylation in inflammation and cancer.

Ma J, Zhang Y, Li J, Dang Y, Hu D Mol Biomed. 2025; 6(1):14.

PMID: 40042761 PMC: 11882493. DOI: 10.1186/s43556-025-00254-x.

Polycomb Repressive Complex 2 in Oncology.

Guo Y, Yu Y, Wang G Cancer Treat Res. 2023; 190:273-320.

PMID: 38113005 DOI: 10.1007/978-3-031-45654-1_9.

Critical Roles of Polycomb Repressive Complexes in Transcription and Cancer.

Dong G, Xu J, Qi Y, Yuan Z, Zhao W Int J Mol Sci. 2022; 23(17).

PMID: 36076977 PMC: 9455514. DOI: 10.3390/ijms23179574.

References

Vecchi M, Confalonieri S, Nuciforo P, Vigano M, Capra M, Bianchi M . Breast cancer metastases are molecularly distinct from their primary tumors. Oncogene. 2007; 27(15):2148-58. DOI: 10.1038/sj.onc.1210858. View

Carvalho J, Van Grieken N, Pereira P, Sousa S, Tijssen M, Buffart T . Lack of microRNA-101 causes E-cadherin functional deregulation through EZH2 up-regulation in intestinal gastric cancer. J Pathol. 2012; 228(1):31-44. DOI: 10.1002/path.4032. View

Weigelt B, Hu Z, He X, Livasy C, Carey L, Ewend M . Molecular portraits and 70-gene prognosis signature are preserved throughout the metastatic process of breast cancer. Cancer Res. 2005; 65(20):9155-8. DOI: 10.1158/0008-5472.CAN-05-2553. View

Baylin S, Ohm J . Epigenetic gene silencing in cancer - a mechanism for early oncogenic pathway addiction?. Nat Rev Cancer. 2006; 6(2):107-16. DOI: 10.1038/nrc1799. View

Kleer C, Cao Q, Varambally S, Shen R, Ota I, Tomlins S . EZH2 is a marker of aggressive breast cancer and promotes neoplastic transformation of breast epithelial cells. Proc Natl Acad Sci U S A. 2003; 100(20):11606-11. PMC: 208805. DOI: 10.1073/pnas.1933744100. View

Fujii S, Tokita K, Wada N, Ito K, Yamauchi C, Ito Y . MEK-ERK pathway regulates EZH2 overexpression in association with aggressive breast cancer subtypes. Oncogene. 2011; 30(39):4118-28. DOI: 10.1038/onc.2011.118. View

Wu S, Zhang Y . Cyclin-dependent kinase 1 (CDK1)-mediated phosphorylation of enhancer of zeste 2 (Ezh2) regulates its stability. J Biol Chem. 2011; 286(32):28511-9. PMC: 3151093. DOI: 10.1074/jbc.M111.240515. View

Becker K, Rosivatz E, Blechschmidt K, Kremmer E, Sarbia M, Hofler H . Analysis of the E-cadherin repressor Snail in primary human cancers. Cells Tissues Organs. 2007; 185(1-3):204-12. DOI: 10.1159/000101321. View

Bossi A, Lehner B . Tissue specificity and the human protein interaction network. Mol Syst Biol. 2009; 5:260. PMC: 2683721. DOI: 10.1038/msb.2009.17. View

10.

Varambally S, Dhanasekaran S, Zhou M, Barrette T, Kumar-Sinha C, Sanda M . The polycomb group protein EZH2 is involved in progression of prostate cancer. Nature. 2002; 419(6907):624-9. DOI: 10.1038/nature01075. View

11.

Schlesinger Y, Straussman R, Keshet I, Farkash S, Hecht M, Zimmerman J . Polycomb-mediated methylation on Lys27 of histone H3 pre-marks genes for de novo methylation in cancer. Nat Genet. 2007; 39(2):232-6. DOI: 10.1038/ng1950. View

12.

ODonnell K, Wentzel E, Zeller K, Dang C, Mendell J . c-Myc-regulated microRNAs modulate E2F1 expression. Nature. 2005; 435(7043):839-43. DOI: 10.1038/nature03677. View

13.

Neri F, Zippo A, Krepelova A, Cherubini A, Rocchigiani M, Oliviero S . Myc regulates the transcription of the PRC2 gene to control the expression of developmental genes in embryonic stem cells. Mol Cell Biol. 2011; 32(4):840-51. PMC: 3272981. DOI: 10.1128/MCB.06148-11. View

14.

Hao X, Sun B, Hu L, Lahdesmaki H, Dunmire V, Feng Y . Differential gene and protein expression in primary breast malignancies and their lymph node metastases as revealed by combined cDNA microarray and tissue microarray analysis. Cancer. 2004; 100(6):1110-22. DOI: 10.1002/cncr.20095. View

15.

Bracken A, Pasini D, Capra M, Prosperini E, Colli E, Helin K . EZH2 is downstream of the pRB-E2F pathway, essential for proliferation and amplified in cancer. EMBO J. 2003; 22(20):5323-35. PMC: 213796. DOI: 10.1093/emboj/cdg542. View

16.

Rodenhiser D . Epigenetic contributions to cancer metastasis. Clin Exp Metastasis. 2008; 26(1):5-18. DOI: 10.1007/s10585-008-9166-2. View

17.

Koh C, Iwata T, Zheng Q, Bethel C, Yegnasubramanian S, De Marzo A . Myc enforces overexpression of EZH2 in early prostatic neoplasia via transcriptional and post-transcriptional mechanisms. Oncotarget. 2011; 2(9):669-83. PMC: 3248223. DOI: 10.18632/oncotarget.327. View

18.

Min J, Zaslavsky A, Fedele G, McLaughlin S, Reczek E, De Raedt T . An oncogene-tumor suppressor cascade drives metastatic prostate cancer by coordinately activating Ras and nuclear factor-kappaB. Nat Med. 2010; 16(3):286-94. PMC: 2903662. DOI: 10.1038/nm.2100. View

19.

Esteller M . Epigenetics in cancer. N Engl J Med. 2008; 358(11):1148-59. DOI: 10.1056/NEJMra072067. View

20.

Sparmann A, van Lohuizen M . Polycomb silencers control cell fate, development and cancer. Nat Rev Cancer. 2006; 6(11):846-56. DOI: 10.1038/nrc1991. View