Breast
CME
Rebecca M. Platoff, MD, MSc (she/her/hers)
Resident in General Surgery
Cooper University Hospital
Cherry Hill, New Jersey, United States
Disclosure(s): No financial relationships to disclose
Rebecca M. Platoff, MD, MSc (she/her/hers)
Resident in General Surgery
Cooper University Hospital
Cherry Hill, New Jersey, United States
Disclosure(s): No financial relationships to disclose
Ping Zhang, PhD
Research Scientist
Cooper University Hospital Department of Surgery, United States
Disclosure information not submitted.
Jaroslav Jelinek, MD PhD
Chief Research Officer
Coriell Institute for Medical Research, United States
Disclosure information not submitted.
Jozef Madzo, PhD
Director of Bioinformatics
Coriell Institute for Medical Research, United States
Disclosure information not submitted.
Gennaro Calendo, MS
Research Scientist
Coriell Institute for Medical Research, United States
Disclosure information not submitted.
Matthew Walt, MS
Research Scientist
Coriell Institute for Medical Research, United States
Disclosure information not submitted.
Umur Atabek, MD
Professor of Surgery
Cooper University Hospital Department of Surgery, United States
Disclosure information not submitted.
Francis R. Spitz, MD
Vice Chairman of Surgery
Cooper University Hospital
Camden, NJ, United States
Disclosure information not submitted.
.jpg "Young K. Hong, MD,MPH,FACS,FSSO photo")
Young K. Hong, MD,MPH,FACS,FSSO
Assistant Professor of Surgery
Cooper University Hospital
Camden, New Jersey, United States
Disclosure information not submitted.
Epigenetic dysregulation has a role in breast cancer tumorigenesis by gene silencing of tumor suppressor genes at histone and promotor region. It has not been correlated with the Oncotype Dx risk stratification tool. We hypothesize epigenetic dysregulation can be modulated to upregulate repressed tumor suppressor gene pathways to decrease risk of tumor recurrence.
Methods:
Tumor samples from 38 patients were immunostained with epigenetic dysregulation markers EZH2 and DNMT1 and correlated to their respective Oncotype Dx scores. MCF7 breast cancer cells were treated in triplicate with either EZH2 inhibitor 3-Deazaneplanocin A (DZNep), DNMT1 inhibitor 5-aza-2’-deoxycytidine (5-AZA), or both at 5 uM for 72 hours. Cell proliferation assay and RNA sequencing were performed for global gene pathway analysis.
Results:
Tumors with high Oncotype scores (n=18) had greater immunostaining than tumors with low score (n=20) for both EZH2 (mean score 4 vs. 2.1, p < 0.001) and DNMT1 (3.8 vs. 2.4, p < 0.001) and Oncotype score directly correlated with both markers (p < 0.001). Treatment of MCF7 with 5-AZA, DZNep and both together reduced cell proliferation by 41.6%, 73.0%, and 73.0% respectively (p = 0.002). RNA sequencing demonstrated good variation in gene expression between treatment groups (PC1 43.61% variation). Heatmap for protein coding genes demonstrated uniform differences between groups. Gene ontology analysis demonstrated that genes more highly expressed in the combined treatment group were related to nuclear division and mRNA production, consistent with increased gene expression. Of the genes used to calculate Oncotype Dx score, BCL2, TFRC, BAG1, ACTB, and HER2 had significantly increased expression in the combination treatment group relative to control (p < 0.05), while RPLP0, MYBL2, and SCUBE2 had significantly decreased expression (p < 0.05). Gene set enrichment analysis revealed increased immune response via allograft rejection pathway (p < 0.001), androgen response pathway (p = .013), estrogen response pathway (p = 0.018) and p53 pathway activity (p < 0.001) with epigenetic treatment. Upregulated genes from this pathway include CCL5 (logFC 5.46, p < 0.001), CSF1 (logFC 4.10, p < 0.001), TGFB2 (logFC 5.07, p < 0.001), and TNF (logFC 5.64, p < 0.001).
Conclusions:
Epigenetic therapy with DZNep and AZA can modulate repressed gene expression silenced by epigenetic dysregulation to potentially mitigate the risk of breast cancer in high-risk patients with elevated Oncotype Dx scores by upregulation of tumor suppressor genes and immunomoduluatory genes. Further investigation is warranted to reduce risk of breast cancer recurrence by epigenetic remodeling of dysregulated gene pathways.