Glioblastoma (GBM) is a primary brain tumor with a five year survival rate of about five percent. While searching for the cells which initiate GBM tumors, researchers isolated glioblastoma stem cells (GSCs). Implanting a low number of these cells into immunocompromised mice yields a lethal tumor which resembles the pathology of the patient's tumor from which the cells were isolated. Oncolytic herpes simplex viruses (oHSV) selectively kill brain tumor cells while sparing normal brain cells. All oHSVs clinically evaluated so far harbor deletions of the neurovirulence gene ?34.5 for safety. GSCs are not permissive to ?34.5-deficient oHSV replication. In contrast, the non-stem like cell lines isolated from the same GBM tumor as the GSCs are permissive. A suppressor mutation which causes immediate early expression of HSV gene Us11 rescues ?34.5-deficient oHSV replication in GSCs. These observations lead me to hypothesize that GSCs express a unique factor, not expressed in the bulk tumor cells, which blocks ?34.5-deficient oHSV replication. Here I propose using a cell culture system which allows us to observe two different cell populations from the same tumor in order to identify novel factor(s) which inhibit ?34.5-deficient oHSV replication. This proposal seeks to identify GSC restriction factor(s) and characterize the HSV-1 Us11 protein's structural functionality in regards to antagonizing these factor(s).

Public Health Relevance

This project aims to identify how glioblastoma stem cells (GSC) are able to inhibit the replication of ?34.5-deficient oncolytic herpes simplex virus-1 (oHSV). The project will first identify when the lifecycle of oHSV is interrupted in GSCs, and whether the same interruption occurs in other stem-like tumor cells. Next this proposal aims to identify which domains of HSV protein (Us11) are responsible for rescuing ?34.5-deficient HSV replication in GSCs and identifying the cellular factor(s) responsible for blocking the virus' replication by using mass spectrometry and shRNA knock down.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
1F31CA192453-01A1
Application #
8976957
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Mcguirl, Michele
Project Start
2015-09-01
Project End
2018-08-31
Budget Start
2015-09-01
Budget End
2016-08-31
Support Year
1
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Harvard Medical School
Department
Biology
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
Peters, Cole; Paget, Max; Tshilenge, Kizito-Tshitoko et al. (2018) RESTRICTION OF ?34.5-DELETED ONCOLYTIC HERPES SIMPLEX VIRUS REPLICATION IN GLIOBLASTOMA STEM-LIKE CELLS. J Virol :
Peters, Cole; Rabkin, Samuel D (2015) Designing Herpes Viruses as Oncolytics. Mol Ther Oncolytics 2: