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Discerning the Mechanism of HLA Expression by Epigenetic Modulators in Breast Cancer Cell Lines
Author(s) -
Terrigino Nicholas Taylor,
Powers Rachel Elizabeth,
O'Donnell Robert Watts
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.806.11
Subject(s) - vorinostat , histone deacetylase inhibitor , human leukocyte antigen , histone deacetylase , cancer research , methyltransferase , cancer cell , cancer , biology , dna methyltransferase , microbiology and biotechnology , gene expression , chemistry , histone , antigen , dna methylation , immunology , biochemistry , methylation , gene , genetics
Our previous studies showed that the combination of a histone deacetylase inhibitor (Entinostat) and a DNA methyltransferase inhibitor (5‐Azacytidine) work in an additive fashion to upregulate surface Human Leukocyte Antigens (HLA) which are typically downregulated in cancer cells. The current study centers on Vorinostat, a histone deacetylase inhibitor, and 5‐Azacytidine, a DNA methyltransferase inhibitor, which allow us to study the regulation of HLA Class 1 expression in the breast cancer cell lines, MDA‐MB‐231 and MCF‐7. Using RT‐qPCR, we are testing for the expression of mRNAs for HLAs and the Antigen Processing Machinery (APM) responsible for placing peptides into these class I proteins and transporting them from the ER to the cell surface. The mRNA levels of APM genes TAP1, TAP2, and LMP2 showed a marked increase upon treatment with the drug combination when compared to the control. The LMP7 mRNA levels showed only a small increase upon treatment with the drug combination when compared to the control. Through flow cytometry, we have demonstrated that, in MCF‐7 cells, the combination of Vorinostat and 5‐Azacytidine caused the highest increase in HLA and Beta‐2 microglobulin expression when compared to each treatment alone. In the case of the MDA‐MB‐231 cells, the drug combination demonstrated the highest increase in Beta‐2 microglobulin expression, but not the highest increase in HLA expression when compared to each treatment alone. Future experiments are planned to determine the amount of HLA protein intracellularly, further assess the APM mRNA levels, and histone positioning at these genes. Discerning the mechanism of the HLA upregulation may help to design treatments which optimize HLA expression, and thus increase the efficacy of new immunotherapies that use checkpoint inhibitors like anti‐CTLA‐4 and anti‐PD‐1. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .