Histone deacetylase 6 inhibition enhances oncolytic viral replication in glioma
Hiroshi Nakashima, … , Timothy P. Cripe, E. Antonio Chiocca
Hiroshi Nakashima, … , Timothy P. Cripe, E. Antonio Chiocca
Published October 20, 2015
Citation Information: J Clin Invest. 2015;125(11):4269-4280. https://doi.org/10.1172/JCI80713.
View: Text | PDF
Research Article Oncology

Histone deacetylase 6 inhibition enhances oncolytic viral replication in glioma

Abstract

Oncolytic viral (OV) therapy, which uses genetically engineered tumor-targeting viruses, is being increasingly used in cancer clinical trials due to the direct cytolytic effects of this treatment that appear to provoke a robust immune response against the tumor. As OVs enter tumor cells, intrinsic host defenses have the potential to hinder viral replication and spread within the tumor mass. In this report, we show that histone deacetylase 6 (HDAC6) in tumor cells appears to alter the trafficking of post-entry OVs from the nucleus toward lysosomes. In glioma cell lines and glioma-stem–like cells, HDAC6 inhibition (HDAC6i) by either pharmacologic or genetic means substantially increased replication of oncolytic herpes simplex virus type 1 (oHSV). Moreover, HDAC6i increased shuttling of post-entry oHSV to the nucleus. In addition, electron microscopic analysis revealed that post-entry oHSVs are preferentially taken up into glioma cells through the endosomal pathway rather than via fusion at the cell surface. Together, these findings illustrate a mechanism of glioma cell defense against an incoming infection by oHSV and identify possible approaches to enhance oHSV replication and subsequent lysis of tumor cells.

Authors

Hiroshi Nakashima, Johanna K. Kaufmann, Pin-Yi Wang, Tran Nguyen, Maria-Carmela Speranza, Kazue Kasai, Kazuo Okemoto, Akihiro Otsuki, Ichiro Nakano, Soledad Fernandez, William F. Goins, Paola Grandi, Joseph C. Glorioso, Sean Lawler, Timothy P. Cripe, E. Antonio Chiocca

×

Figure 1

The HDAC6-specific inhibitor, tubacin, improves HSV-1–mediated gene expression and oHSV replication.

Options: View larger image (or click on image) Download as PowerPoint
The HDAC6-specific inhibitor, tubacin, improves HSV-1–mediated gene expr...
(A) Bioluminescence (measured as RLU) assay was performed 24 hours after infection with a replication-defective HSV-1 encoding a Fluc cDNA of U251 cells (MOI of 3). (B) Replication of rQNestin34.5 (MOI of 0.1) in tubacin-treated (dashed line) and control U251 cells (solid line). The input dose was given at 0 hours. (C) Titration of oHSV-infected (rQNestin34.5-infected) U251 cells (MOI of 0.03) in the presence of IFN-β, with and without VPA or tubacin, 3 days after infection. Doses of tubacin and IFN-β were 5 μM and 1,000 units/ml, respectively. (D) LDH cytotoxicity assay 3 days after infection of U251 cells by rQNestin34.5 in the presence of tubacin (0, 1, 2, and 5 μM; starting at 14 hours before infection). (E) LDH cytotoxicity assay 5 days after infection of U251 cells by rQNestin34.5 in the presence of CI994 (0, 1, and 3 μM; starting at 14 hours before infection). (F) LHD cytotoxicity assay of U251 cells in the presence of tubacin for 5 days. *P < 0.05, **P < 0.01, ***P < 0.001 by 1-way ANOVA test in A–C and F) and 1-way ANOVA with Turkey’s multiple comparisons tests in D and E. Error bars correspond to mean ± SD (n = 3; in A–C and n = 4; in F). Horizontal bars represent the average in A–C. Bars represent the average (n = 4; in D–F) (See also Supplemental Figure 1.).