Molecular engineering and validation of an oncolytic herpes simplex virus type 1 transcriptionally targeted to midkine-positive tumors.
BACKGROUND
Expression profile analyses of midkine (MDK), a multifunctional protein important in development but repressed postnataly, indicate that it is highly expressed in approximately 80% of adult carcinomas and many childhood cancers including malignant peripheral nerve sheath tumors (MPNST). In the present study, we sought to leverage its selective expression to develop a novel oncolytic herpes simplex virus (oHSV) capable of targeting developmentally primitive cancers that express MDK.


METHODS
We sought to increase the oncolytic efficacy of the virus by fusing the human MDK promoter to the HSV type 1 neurovirulence gene, gamma(1)34.5, whose protein product increases viral replication.


RESULTS
Tissue-specific MDK promoter activity in human tumor cells and transgene biological activity was confirmed in human MPNST tumor cells. In vitro replication and cytotoxicity in human fibroblasts and MPNST cells by plaque and MTT assays showed that oHSV-MDK-34.5 increased replication and cytotoxicity compared to oHSV-MDK-Luc. By contrast, no significant difference in cytotoxicity was detected between these viruses in normal human fibroblasts. oHSV-MDK-34.5 impaired in vivo tumor growth and increased median survival of MPNST tumor-bearing nude mice.


CONCLUSIONS
The transcriptional targeting of HSV lytic infection to MDK-expressing tumor cells is feasible. oHSV-MDK-34.5 shows enhanced anti-tumor effects both in vitro and in vivo. Further studies are warranted and may lead to its use in clinical trials.
Maldonado
Arturo R
AR
Division of Pediatric General and Thoracic Surgery, The Center For Molecular Fetal Therapy, Children's Hospital Medical Center, Cincinnati, OH, USA.
Klanke
Chuck
C
Jegga
Anil G
AG
Aronow
Bruce J
BJ
Mahller
Yonatan Y
YY
Cripe
Timothy P
TP
Crombleholme
Timothy M
TM
D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D003602:Cytotoxicity, Immunologic; D005260:Female; D055785:Gene Knockdown Techniques; D005818:Genetic Engineering / Q000379:methods*; D018259:Herpesvirus 1, Human / Q000235:genetics* / Q000502:physiology; D006801:Humans; D008156:Luciferases / Q000235:genetics; D051379:Mice; D008819:Mice, Nude; D000078792:Midkine; D009414:Nerve Growth Factors / Q000378:metabolism*; D018317:Nerve Sheath Neoplasms / Q000235:genetics / Q000628:therapy*; D050130:Oncolytic Virotherapy / Q000379:methods*; D050504:Oncolytic Viruses / Q000235:genetics* / Q000502:physiology; D034741:RNA, Small Interfering / Q000378:metabolism; D016019:Survival Analysis; D014158:Transcription, Genetic; D019076:Transgenes / Q000235:genetics; D014779:Virus Replication / Q000502:physiology; D023041:Xenograft Model Antitumor Assays
C066254:MDK protein, human; D009414:Nerve Growth Factors; D034741:RNA, Small Interfering; D000078792:Midkine; D008156:Luciferases