Targeting Histone Methyltransferase DOT1L by a Novel Psammaplin A Analog Inhibits Growth and Metastasis of Triple-Negative Breast Cancer

Abstract

Triple-negative breast cancer (TNBC) is the most intractable cancer in women with a high risk of metastasis. While hyper-methylation of histone H3 catalyzed by disruptor of telomeric silencing 1-like (DOT1L), a specific methyltransferase for histone H3 at lysine residue 79 (H3K79), is reported as a potential target for TNBCs, early developed nucleoside-type DOT1L inhibitors are not sufficient for effective inhibition of growth and metastasis of TNBC cells. We found that TNBC cells had a high expression level of DOT1L and a low expression level of E-cadherin compared to normal breast epithelial cells and non-TNBC cells. Here, a novel psammaplin A analog (PsA-3091) exhibited a potent inhibitory effect of DOT1L-mediated H3K79 methylation. Consistently, PsA-3091 also significantly inhibited the proliferation, migration, and invasion of TNBC cells along with the augmented expression of E-cadherin and the suppression of N-cadherin, ZEB1, and vimentin expression. In an orthotopic mouse model, PsA-3091 effectively inhibited lung metastasis and tumor growth by the regulation of DOT1L activity and EMT biomarkers. Together, we report here a new template of DOT1L inhibitor and suggest that targeting DOT1L-mediated H3K79 methylation by a novel PsA analog may be a promising strategy for the treatment of metastatic breast cancer patients.

Anti-Proliferative Activity of Nodosin, a Diterpenoid from Isodon serra, via Regulation of Wnt/β-Catenin Signaling Pathways in Human Colon Cancer Cells

“…Total cell lysates were mixed with lysis buffer, and boiled for 10-20 min at 100°C. The protein concentrations of the cell lysates were determined by the BCA protein assay ( Byun et al ., 2019 ). Samples containing equal amounts of protein were subjected to SDS-polyacrylamide gel electrophoresis.…”

Antiproliferative and Antimigration Activities of Fluoro-Neplanocin A via Inhibition of Histone H3 Methylation in Triple-Negative Breast Cancer

“…Our findings suggested that the inhibitory effect of NepA on the production of SAM via the inhibition of SAH might also affect the histone methylation status of human cancer cells. In BC, the upregulated methylation of H3K79 (H3K79me) is known to be correlated strongly with a poor clinical outcome [2]. Therefore, we focused on DOT1L expression and DOT1L-mediated methylation levels in BC cells.…”

“…Breast cancer (BC) is the most commonly occurring cancer and second leading cause of cancer-related death in women worldwide [1,2]. Chemotherapy, radiation therapy, and surgical options such as mastectomy or lumpectomy have been identified as the most effective and common strategies for the treatment of early-stage BC.…”

“…Each epigenetic process is regulated by specific enzymes and their interactions. Disruptor of telomeric silencing 1-like (DOT1L), a histone methyltransferase specific for the lysine 79 residue of histone H3 (H3K79), was recently reported to promote the development of mixed lineage leukemia (MLL)-rearranged leukemia and the proliferation and metastasis of BC [2,[16][17][18][19]. Although this discovery has led to a clinical trial of the DOT1L inhibitor EPZ-5676 for the treatment of leukemias harboring a rearrangement of the MLL gene, existing DOT1L inhibitors did not sufficiently suppress breast tumor growth and metastasis in an earlier study [20].…”

The Antiproliferative Activity of Oxypeucedanin via Induction of G2/M Phase Cell Cycle Arrest and p53-Dependent MDM2/p21 Expression in Human Hepatoma Cells

“…Each protein was subjected to 6-15% SDS-PAGE. Proteins were transferred onto PVDF membranes (Millipore, Bedford, MA, USA) by electroblotting, and membranes were blocked for 1 h with blocking buffer [5% bovine serum albumin (BSA) in tris-buffered saline-0.1% Tween 20 (TBST)] at room temperature [38]. Membranes were then incubated with indicated antibodies (mouse anti-β-actin, diluted 1:10,000; other antibodies, diluted 1:500-1:1000 in 5% BSA/TBST) overnight at 4 • C and washed three times for 10 min with TBST.…”