Killing of p53-deficient hepatoma cells by parvovirus H-1 and chemotherapeutics requires promyelocytic leukemia protein.
OBJECTIVE
To evaluate the synergistic targeting and killing of human hepatocellular carcinoma (HCC) cells lacking p53 by the oncolytic autonomous parvovirus (PV) H-1 and chemotherapeutic agents and its dependence on functional promyelocytic leukemia protein (PML).


METHODS
The role of p53 and PML in regulating cytotoxicity and gene transfer mediated by wild-type (wt) PV H-1 were explored in two pairs of isogenic human hepatoma cell lines with different p53 status. Furthermore, H-1 PV infection was combined with cytostatic drug treatment.


RESULTS
While the HCC cells with different p53 status studied were all susceptible to H-1 PV-induced apoptosis, the cytotoxicity of H-1 PV was more pronounced in p53-negative than in p53-positive cells. Apoptosis rates in p53-negative cell lines treated by genotoxic drugs were further enhanced by a treatment with H-1 PV. In flow cytometric analyses, H-1 PV infection resulted in a reduction of the mitochondrial transmembrane potential. In addition, H-1 PV cells showed a significant increase in PML expression. Knocking down PML expression resulted in a striking reduction of the level of H-1 PV infected tumor cell death.


CONCLUSIONS
H-1 PV is a suitable agent to circumvent the resistance of p53-negative HCC cells to genotoxic agents, and it enhances the apoptotic process which is dependent on functional PML. Thus, H-1 PV and its oncolytic vector derivatives may be considered as therapeutic options for HCC, particularly for p53-negative tumors.
Sieben
Maike
M
First Department of Internal Medicine of Johannes Gutenberg University of Mainz, Mainz, Germany.
Herzer
Kerstin
K
Zeidler
Maja
M
Heinrichs
Vera
V
Leuchs
Barbara
B
Schuler
Martin
M
Cornelis
Jan-J
JJ
Galle
Peter-R
PR
Rommelaere
Jean
J
Moehler
Markus
M
D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism / Q000821:virology*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology / Q000627:therapeutic use; D003131:Combined Modality Therapy; D004358:Drug Therapy; D005472:Fluorouracil / Q000494:pharmacology / Q000627:therapeutic use; D052661:H-1 parvovirus / Q000472:pathogenicity*; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000821:virology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009687:Nuclear Proteins / Q000378:metabolism*; D000071156:Promyelocytic Leukemia Protein; D014157:Transcription Factors / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
D000970:Antineoplastic Agents; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C070576:PML protein, human; D002945:Cisplatin; D005472:Fluorouracil