Abstract 3722
Background
Histone acetylation plays an important role in regulating the chromatin structure and is tightly regulated by histone acetyltransferases (HAT) and histone deacetylases (HDAC). Recent studies have demonstrated that several chromatin-regulating proteins can modulate cellular responses to other cytotoxic modalities including ionizing radiation and chemotherapeutic drugs. Even though histone acetylation is one of the key mechanisms of epigenetic regulation, relatively little is known about the cancer therapeutic potential of HAT inhibitors. This is in stark contrast to the well-studied effects of HDAC inhibitors. In this study, we investigated the proton beam-sensitizing effect of C646, a selective small molecule inhibitor of p300 histone acetyltransferase in human pancreatic cancer cells.
Methods
Cell viability assay (CCK-8; Dojindo), Clonogenic survival assay, Cell cycle analysis (PI staining). Annexin V-FITC and PI staining, γ-H2AX foci, Western blot, BxPC-3 Xenograft tumor model, TUNEL assay.
Results
AsPC-1, BxPC-3 and Mia-paca2 cells exhibited increase in radiosensitivity when exposed to C646 at all doses of proton beam tested. C646 pre-treatment induce led to increase of sub-G1 population and abolishment of G2/M arrest. Flow cytometry analysis with annexin V staining and Western blot analysis showed that The pre-treatment with C646 significantly enhanced proton-induced apoptotic cell death through the down-regulation of anti-apoptotic molecules. Our in vivo results demonstrate synergistic effects of combination therapy with C646 and proton beam. In BxPC-3 xenograft tumor model, C646 pre-treatment increased proton-induced tumor growth inhibition and apoptotic cell death in tumor tissues. In addition, the combination treatment of C646 with proton beam increased DNA damage and decreased activation of DNA repair pathway compared with proton alone.
Conclusions
Our results suggest that the C646 may increase proton- induced apoptosis through the modulation of various pro- and anti- apoptotic molecules in human pancreatic cancer cells. These results provide proof of principle that the inhibition of histone acetylation by HATis can be exploited to develop new proton-sensitizer.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
National Research Foundation of Korea (NRF).
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4883 - A New Population Model Validated Pharmacokinetic Similarity of HLX01 and Rituximab in B-Cell Lymphoma
Presenter: Yuankai Shi
Session: Poster Display session 1
Resources:
Abstract
4908 - Efficacy of salvage therapy in the treatment of Helicobacter pylori-positive gastric low-grade mucosa-associated lymphoid tissue lymphoma
Presenter: Sung-Nam Lim
Session: Poster Display session 1
Resources:
Abstract
2360 - Mutational analysis of extranodal marginal zone lymphoma using next generation sequencing
Presenter: Seok Jae Huh
Session: Poster Display session 1
Resources:
Abstract
2430 - Clinical features, treatment and outcomes of colon and rectum mucosa-associated lymphoid tissue (MALT) lymphoma: Literature reviews published in English between 1993 and 2017
Presenter: Jeong Yeon Kim
Session: Poster Display session 1
Resources:
Abstract
4654 - Splenic marginal zone lymphoma: clinical characteristics and prognostic factors in a series of 52 patients
Presenter: Guldane Cengiz Seval
Session: Poster Display session 1
Resources:
Abstract
1732 - Safety and efficacy of Bendamustine and Rituximab (BR) regimen in Indian Chronic Lymphocytic Leukemia patients
Presenter: Ajay Gogia
Session: Poster Display session 1
Resources:
Abstract
5784 - N-terminal B-type natriuretic peptide (NT-proBNP) as an independed prognostic marker for patients with newly diagnosed multiple myeloma complicated by dialysis-dependent renal failure
Presenter: Sergey Semochkin
Session: Poster Display session 1
Resources:
Abstract
836 - The first-line effect of Bortezomib-based Therapy on Clinical Outcomes for Taiwanese Patients with multiple myeloma
Presenter: Ching-Liang Ho
Session: Poster Display session 1
Resources:
Abstract
2085 - Impact of Donor Lymphocyte Infusion in Relapsing Myeloid Neoplasms Post Allogeneic Hematopoietic Stem Cell Transplantation
Presenter: Hanafy Hafez
Session: Poster Display session 1
Resources:
Abstract
6079 - Invasive fungal diseases in patients with Hodgkin’s lymphoma before and after allogeneic hematopoietic stem cell transplantation
Presenter: Marina Popova
Session: Poster Display session 1
Resources:
Abstract