title: Mitochondrial apoptosis and FAK signaling disruption by a novel histone deacetylase inhibitor, HTPB, in antitumor and antimetastatic mouse models.
abstract: BACKGROUND
  Compound targeting histone deacetylase (HDAC) represents a new era in molecular cancer therapeutics. However, effective HDAC inhibitors for the treatment of solid tumors remain to be developed.
  
  
  RESULTS
  Here, we propose a novel HDAC inhibitor, N-Hydroxy-4-(4-phenylbutyryl-amino) benzamide (HTPB), as a potential chemotherapeutic drug for solid tumors. The HDAC inhibition of HTPB was confirmed using HDAC activity assay. The antiproliferative and anti-migratory mechanisms of HTPB were investigated by cell proliferation, flow cytometry, DNA ladder, caspase activity, Rho activity, F-actin polymerization, and gelatin-zymography for matrix metalloproteinases (MMPs). Mice with tumor xenograft and experimental metastasis model were used to evaluate effects on tumor growth and metastasis. Our results indicated that HTPB was a pan-HDAC inhibitor in suppressing cell viability specifically of lung cancer cells but not of the normal lung cells. Upon HTPB treatment, cell cycle arrest was induced and subsequently led to mitochondria-mediated apoptosis. HTPB disrupted F-actin dynamics via downregulating RhoA activity. Moreover, HTPB inhibited activity of MMP2 and MMP9, reduced integrin-β1/focal adhesion complex formation and decreased pericellular poly-fibronectin assemblies. Finally, intraperitoneal injection or oral administration of HTPB efficiently inhibited A549 xenograft tumor growth in vivo without side effects. HTPB delayed lung metastasis of 4T1 mouse breast cancer cells. Acetylation of histone and non-histone proteins, induction of apoptotic-related proteins and de-phosphorylation of focal adhesion kinase were confirmed in treated mice.
  
  
  CONCLUSIONS
  These results suggested that intrinsic apoptotic pathway may involve in anti-tumor growth effects of HTPB in lung cancer cells. HTPB significantly suppresses tumor metastasis partly through inhibition of integrin-β1/FAK/MMP/RhoA/F-actin pathways. We have provided convincing preclinical evidence that HTPB is a potent HDAC targeted inhibitor and is thus a promising candidate for lung cancer chemotherapy.
authors.affiliation: Department of Internal Medicine, Chi Mei Medical Center, Tainan, Taiwan.
authors.forename: Jiunn-Min
authors.initials: JM
authors.lastname: Shieh
authors.forename: Tzu-Tang
authors.initials: TT
authors.lastname: Wei
authors.forename: Yen-An
authors.initials: YA
authors.lastname: Tang
authors.forename: Sin-Ming
authors.initials: SM
authors.lastname: Huang
authors.forename: Wei-Ling
authors.initials: WL
authors.lastname: Wen
authors.forename: Mei-Yu
authors.initials: MY
authors.lastname: Chen
authors.forename: Hung-Chi
authors.initials: HC
authors.lastname: Cheng
authors.forename: Santosh B
authors.initials: SB
authors.lastname: Salunke
authors.forename: Ching-Shih
authors.initials: CS
authors.lastname: Chen
authors.forename: Pinpin
authors.initials: P
authors.lastname: Lin
authors.forename: Chien-Tien
authors.initials: CT
authors.lastname: Chen
authors.forename: Yi-Ching
authors.initials: YC
authors.lastname: Wang
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001549:Benzamides / Q000494:pharmacology*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005260:Female; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D023041:Xenograft Model Antitumor Assays
chemical_list: D001549:Benzamides; D056572:Histone Deacetylase Inhibitors; C482219:N-hydroxy-4-(4-phenylbutyrylamino)benzamide; D019253:Proto-Oncogene Proteins c-bcl-2; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020169:Caspases; D006655:Histone Deacetylases