Preclinical assessment of FHIT gene replacement therapy in human leukemia using a chimeric adenovirus, Ad5/F35
Flavia Pichiorri1, Francesco Trapasso, Tiziana Palumbo
1Ohio State University Comprehensive Cancer Center, Columbus, Ohio 43210, USA. pichiorri.1@osu.edu
Purpose:
Expression of the FHIT protein is lost or reduced in most solid tumors and a significant fraction of hematopoietic malignancies. Adenovirus 5 (Ad5) virus or adeno-associated viral vectors have been used to study the tumor suppressor function of FHIT in solid tumors, but these tools have not been effective in leukemias. We have generated a chimeric FHIT-containing adenovirus composed of Ad5 and the group B adenovirus called F35 with which we have been able to efficiently infect hematopoietic cells.
Experimental Design:
Infection efficiency of Ad5/F35-FHIT and Ad5/F35-GFP viruses was tested in leukemia cell lines that lacked FHIT expression, and biological effects of successful infection were assessed. An acute myelogenous leukemia, a chronic myelogenous leukemia, and four acute lymphoblastic leukemia human cell lines were examined as well as two EBV-transformed B lymphoblastoid cell lines that expressed endogenous FHIT.
Results:
Two of four acute lymphoblastic leukemia cell lines, Jurkat and MV4;11, which were efficiently infected with Ad5/F35-FHIT, underwent growth suppression and massive induction of apoptosis without apparent activation of caspase-8 or caspase-2 and late activation of caspase-3. Treatment of infected cells with caspase-9 and caspase-3 inhibitors partially blocked FHIT-induced apoptosis. The two remaining infected acute lymphoblastic leukemia cell lines, Molt-3 and RS4;11, were apparently unaffected. Restoration of FHIT expression in the chronic myelogenous leukemia K562 cell line and the acute myelogenous leukemia KG1a cell line also induced apoptosis but at later time points than seen in the acute lymphoblastic leukemia Jurkat and MV4;11 cell lines. I.v. injection of Ad5/F35-FHIT-infected Jurkat cells resulted in abrogation of tumorigenicity in the NOD/SCID xenogeneic engraftment model.
Conclusion:
FHIT restoration in some FHIT-deficient leukemia cells induces both antiproliferative and proapoptotic effects involving the intrinsic caspase apoptotic pathway.
Insights
A novel adenovirus vector effectively delivers the FHIT gene into leukemia cells, suppressing tumor growth and inducing apoptosis. This FHIT restoration shows promise for treating FHIT-deficient leukemias.
Area of Science:
- Oncology
- Gene Therapy
- Molecular Biology
Background:
- FHIT protein loss is common in solid tumors and leukemias.
- Adenovirus 5 (Ad5) and AAV vectors are ineffective for FHIT delivery in leukemias.
- A new Ad5/F35 chimeric adenovirus vector efficiently infects hematopoietic cells.
Purpose of the Study:
- To evaluate the tumor suppressor function of FHIT in leukemia.
- To assess the efficacy of a novel Ad5/F35 chimeric adenovirus vector for FHIT delivery in leukemia cells.
Main Methods:
- Infection of FHIT-deficient leukemia cell lines with Ad5/F35-FHIT and Ad5/F35-GFP viruses.
- Assessment of biological effects, including cell growth and apoptosis.
- Xenogeneic engraftment model to evaluate tumorigenicity.
Main Results:
- Ad5/F35-FHIT efficiently infected Jurkat and MV4;11 ALL cell lines, causing growth suppression and apoptosis.
- FHIT restoration induced apoptosis via the intrinsic caspase pathway (caspase-9 and caspase-3).
- Ad5/F35-FHIT-infected Jurkat cells showed abrogated tumorigenicity in vivo.
Conclusions:
- FHIT restoration using the Ad5/F35 vector has antiproliferative and proapoptotic effects in FHIT-deficient leukemia cells.
- The Ad5/F35-FHIT vector is a promising tool for FHIT-based leukemia therapy.
- FHIT-induced apoptosis involves the intrinsic caspase pathway.
