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Retrovirus‐mediated transfer of the herpes simplex virus thymidine kinase and connexin26 genes in pancreatic cells results in variable efficiency on the bystander killing: Implications for gene therapy
Author(s) -
Carrió Meritxell,
Mazo Adela,
LópezIglesias Carmen,
Estivill Xavier,
Fillat Cristina
Publication year - 2001
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.1429
Subject(s) - bystander effect , thymidine kinase , pancreatic cancer , retrovirus , genetic enhancement , biology , connexin , herpes simplex virus , cytotoxic t cell , cancer research , suicide gene , ganciclovir , microbiology and biotechnology , virology , virus , gene , gap junction , immunology , cancer , intracellular , biochemistry , genetics , in vitro , human cytomegalovirus
Abstract Currently, there is no effective treatment for pancreatic cancer and prodrug‐activating gene therapy with the herpes simplex virus thymidine kinase gene (HSV‐tk) in combination with ganciclovir (GCV) has been suggested as a candidate approach against this disease. In the present study, we have evaluated the efficacy of the HSV‐tk/GCV treatment in a panel of pancreatic tumor cells (NP‐9, NP‐18, NP‐31) and the potentiation of the cytotoxic effect in combination with the overexpression of the connexin 26 gene (Cx26). Pancreatic cells transduced with a retrovirus containing the HSV‐tk gene showed different sensitivities to GCV that seemed to be independent of HSV‐tk expression levels. The extent of the bystander effect also varied among the pancreatic tumor cells and correlated with the level of gap junction intercellular communication (GJIC). Transduction of the pancreatic tumor cells with a retrovirus carrying the connexin 26 gene resulted in high levels of connexin 26 expression and in an increase in the GJIC that correlated to an extent in the bystander effect in both NP‐9Cx26 and NP‐18Cx26 cells. Neither an increment in GJIC nor an increase in the bystander killing was detected in NP‐31Cx26. The bystander effect in NP‐18 Cx26 cells was also prevented by the long term inhibitor of GJIC, 18‐α‐glycyrrhetinic acid (AGA). Together, these results demonstrate that pancreatic tumor cells are highly different as regards the susceptibility to HSV‐tk/GCV treatment. Moreover, they indicate that overexpression of the Cx26 gene does not always correspond to an increase in GJIC although they clearly suggest the role of GJIC in mediating the bystander effect. © 2001 Wiley‐Liss, Inc.