title: Combined Inhibition of DNMT and HDAC Blocks the Tumorigenicity of Cancer Stem-like Cells and Attenuates Mammary Tumor Growth.
abstract: Recently, impressive technical advancements have been made in the isolation and validation of mammary stem cells and cancer stem cells (CSC), but the signaling pathways that regulate stem cell self-renewal are largely unknown. Furthermore, CSCs are believed to contribute to chemo- and radioresistance. In this study, we used the MMTV-Neu-Tg mouse mammary tumor model to identify potential new strategies for eliminating CSCs. We found that both luminal progenitor and basal stem cells are susceptible to genetic and epigenetic modifications, which facilitate oncogenic transformation and tumorigenic potential. A combination of the DNMT inhibitor 5-azacytidine and the HDAC inhibitor butyrate markedly reduced CSC abundance and increased the overall survival in this mouse model. RNA-seq analysis of CSCs treated with 5-azacytidine plus butyrate provided evidence that inhibition of chromatin modifiers blocks growth-promoting signaling molecules such as RAD51AP1 and SPC25, which play key roles in DNA damage repair and kinetochore assembly. Moreover, RAD51AP1 and SPC25 were significantly overexpressed in human breast tumor tissues and were associated with reduced overall patient survival. In conclusion, our studies suggest that breast CSCs are intrinsically sensitive to genetic and epigenetic modifications and can therefore be significantly affected by epigenetic-based therapies, warranting further investigation of combined DNMT and HDAC inhibition in refractory or drug-resistant breast cancer. Cancer Res; 76(11); 3224-35. ©2016 AACR.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Rajneesh
authors.initials: R
authors.lastname: Pathania
authors.affiliation: Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas.
authors.forename: Sabarish
authors.initials: S
authors.lastname: Ramachandran
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Gurusamy
authors.initials: G
authors.lastname: Mariappan
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Thakur
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia. CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Huidong
authors.initials: H
authors.lastname: Shi
authors.affiliation: CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia. Department of Biostatistics, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Jeong-Hyeon
authors.initials: JH
authors.lastname: Choi
authors.affiliation: CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia. Immunotherapy Center, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Santhakumar
authors.initials: S
authors.lastname: Manicassamy
authors.affiliation: CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia. Department of Pathology, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Ravindra
authors.initials: R
authors.lastname: Kolhe
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia. CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Puttur D
authors.initials: PD
authors.lastname: Prasad
authors.affiliation: CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia. Department of Pathology, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Suash
authors.initials: S
authors.lastname: Sharma
authors.affiliation: CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia. Charlie Norwood VA Medical Center and Department of Medicine and Surgery, Medical College of Georgia, Augusta University, Augusta, Georgia.
authors.forename: Bal L
authors.initials: BL
authors.lastname: Lokeshwar
authors.affiliation: Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas.
authors.forename: Vadivel
authors.initials: V
authors.lastname: Ganapathy
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia. CRU Cancer Center, Medical College of Georgia, Augusta University, Augusta, Georgia. mthangaraju@gru.edu.
authors.forename: Muthusamy
authors.initials: M
authors.lastname: Thangaraju
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis; D001374:Azacitidine / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000235:genetics; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D002280:Basal Cell Carcinoma / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D049109:Cell Proliferation; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors*; D004359:Drug Therapy, Combination; D005260:Female; D059014:High-Throughput Nucleotide Sequencing; D056284:Histone Deacetylase 1 / Q000037:antagonists & inhibitors*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006801:Humans; D007124:Immunoenzyme Techniques; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D008819:Mice, Nude; D016513:Mice, SCID; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D056572:Histone Deacetylase Inhibitors; D012333:RNA, Messenger; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D001374:Azacitidine