Relationship between 31P metabolites and oncolytic viral therapy sensitivity in human colorectal cancer xenografts.
BACKGROUND
Studies using phosphorus magnetic resonance spectroscopy (MRS) have pointed to the significance of phospholipid metabolite alterations as biochemical markers for tumour progression or therapy response.


METHODS
Spectroscopic imaging was performed in colorectal flank tumours in nude mice. In vivo tumour doubling times for each cell line were measured. In vivo sensitivity of each tumour line to treatment with G207 and NV1020 oncolytic viruses was assessed. Correlations between viral sensitivity and tumour doubling time and phosphorus MRS were estimated.


RESULTS
For G207 virus, in vitro cytotoxicity tests showed cell viability at multiplicities of infection (ratio of viral particles per tumour cell) of 0.1 on day 6 as follows: C85, less than 1 per cent; HCT8, 1 per cent; LS174T, 9 per cent; HT29, 18 per cent; and C18, 92 per cent. Respective values for NV1020 were 1, 18, 4, 18 and 86 per cent. The phosphoethanolamine to phosphocholine ratio was significantly lower in virus-sensitive than -insensitive cells, and was dependent on tumour doubling time.


CONCLUSIONS
Alterations in membrane phospholipid metabolites that relate to proliferation of cancer cells affect the efficacy of oncolytic viral therapy. MRS proved a highly sensitive non-invasive tool for predicting the efficacy of viruses.
Silberhumer
G R
GR
Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA.
Zakian
K
K
Malhotra
S
S
Brader
P
P
Gönen
M
M
Koutcher
J
J
Fong
Y
Y
D000818:Animals; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000628:therapy*; D004926:Escherichia coli / Q000378:metabolism*; D005822:Genetic Vectors; D018259:Herpesvirus 1, Human / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D050130:Oncolytic Virotherapy; D010743:Phospholipids / Q000378:metabolism*; D010759:Phosphorus Isotopes; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014162:Transfection; D014183:Transplantation, Heterologous
D010743:Phospholipids; D010759:Phosphorus Isotopes; D019275:Radiopharmaceuticals