Lack of Bystander Killing in Herpes Simplex Virus Thymidine Kinase-Transduced Colon Cell Lines Due to Deficient Connexin43 Gap Junction Formation
- 10 October 1998
- journal article
- research article
- Published by Mary Ann Liebert Inc in Human Gene Therapy
- Vol. 9 (15) , 2253-2261
- https://doi.org/10.1089/hum.1998.9.15-2253
Abstract
The efficacy of herpes simplex virus thymidine kinase (HSV-TK) gene therapy for colorectal carcinoma has been investigated in an in vitro system. The magnitude and the mechanism of the HSV-TK bystander effect was determined in three human colon tumor cell lines: HCT-116, HCT-8, and HT-29. Each HSV-TK(+) cell line was generated by stable transduction with a bicistronic retroviral vector containing the HSV-TK and neomycin resistance (neo) genes; each exhibited an IC50 for GCV of ≤4 μM. When GCV was added to HSV-TK(+) cells mixed with parental cells or known bystander-positive cell lines, no bystander killing was evident in the HT-29 or HCT-8 cells. Western blots detected the expression of the gap junction protein connexin43 (Cx43) in HCT-8 and HT-29 cells; however, immunolocalization studies indicated predominantly cytoplasmic staining of Cx43 and no cell surface staining in these cell lines. Stable transfection of HCT-8 and HT-29 cells with Cx43 resulted in increased levels of Cx43 expression with the same subcellular distribution as before, yet there was again no apparent bystander killing. In contrast, Cx43 expression was localized to the cell surface in the bystander-positive colon tumor cell line HCT-116. These results demonstrate that expression and proper surface localization of Cx43 gap junctions are necessary components of the bystander effect in human colon tumor cells. They also indicate that future combination gene therapy approaches using coexpression of HSV-TK and Cx43 genes may not be applicable to all tumor systems. We investigated the use of herpes simplex virus thymidine kinase/ganciclovir (HSV-TK/GCV) suicide gene therapy for the treatment of colorectal carcinoma. In spite of expression of connexin43, two colon tumor cell lines, HT-29 and HCT-8, did not exhibit bystander effect killing in comparison with the bystander-positive HCT-116 human colon tumor cell line. We demonstrate that the absence of bystander effect killing in these tumor cell lines is correlated with the lack of functional connexin43 gap junctions at the cell surface.Keywords
This publication has 33 references indexed in Scilit:
- A “Distant” Bystander Effect of Suicide Gene Therapy: Regression of Nontransduced Tumors Together with a Distant Transduced TumorHuman Gene Therapy, 1997
- Bystander Effects of Different Enzyme-Prodrug Systems for Cancer Gene Therapy Depend on Different Pathways for Intercellular Transfer of Toxic Metabolites, a Factor That Will Govern Clinical Choice of Appropriate RegimesHuman Gene Therapy, 1997
- Retinoids augment the bystander effect in vitro and in vivo in herpes simplex virus thymidine kinase/ganciclovir-mediated gene therapyGene Therapy, 1997
- Metabolism and activities of 3′-azido-2′,3′-dideoxythymidine and 2′,3′-didehydro-2′,3′-dideoxythymidine in herpesvirus thymidine kinase transduced T-lymphocytesAntiviral Research, 1997
- Mechanism of ‘bystander effect’ killing in the herpes simplex thymidine kinase gene therapy model of cancer treatmentGene Therapy, 1997
- The Thymidine Kinase/Ganciclovir-Mediated “Suicide” Effect Is Variable in Different Tumor CellsHuman Gene Therapy, 1995
- The “Bystander Effect”: Association of U-87 Cell Death with Ganciclovir-Mediated Apoptosis of Nearby Cells and Lack of Effect in Athymic MiceHuman Gene Therapy, 1995
- Modulation of Connexin43 Expression:Journal of Cardiovascular Electrophysiology, 1995
- In VitroEvidence That Metabolic Cooperation Is Responsible for the Bystander Effect Observed with HSVtkRetroviral Gene TherapyHuman Gene Therapy, 1993
- Multisubunit assembly of an integral plasma membrane channel protein, gap junction connexin43, occurs after exit from the ERCell, 1993