Increased apoptosis and decreased proliferation of colorectal cancer cells using insulin-like growth factor binding protein-4 gene delivered locally by gene transfer.
OBJECTIVE
Insulin-like growth factor (IGF)-I induces proliferation of transformed cells. Its binding proteins (IGFBP) are involved in local regulation of IGF. This study assessed the effects of overexpression of IGFBP-4 on the development of cancer in vivo.


METHODS
Nude mice were subcutaneously inoculated with HT-29 colorectal cancer cells (3 x 10(6)). When the tumour became visible (1 week after inoculation), animals received either 150 microg of mammalian expression vector containing IGFBP-4 cDNA or vector alone (n = 6 each) by peritumoural injection. Tumour size was measured during the growth. After 3 weeks of IGFBP-4 induction, animals were killed and tumour tissue samples were collected for examining the level of IGFBP-4 expression. Tumour mitotic activities were determined by counting numbers of mitotic cells on the tissue section. Apoptosis was investigated by terminal deoxynucleotidyl transferase-mediated dUDP nick end labelling assay.


RESULTS
Following IGFBP-4 treatment, tumour showed large necrotic areas, significantly increased numbers of apoptotic cells (36.67 +/- 7.36 vs 7.07 +/- 1.91, P < 0.01 vs control), decreased cells undergoing mitosis (2.31 +/- 0.32 vs 3.61 +/- 0.27, P < 0.01 vs control) and higher expression of IGFBP-4 (P < 0.05 vs control).


CONCLUSIONS
IGFBP-4 gene transfer increased apoptosis and decreased mitosis, but tumour volume was not significantly altered possibly due to cellular debris filling the centre of tumours.
Durai
R
R
Academic Division of Surgical and Interventional Sciences, University College London, Hampstead Campus, Royal Free Hampstead NHS Trust Hospital, London, UK.
Yang
S Y
SY
Sales
K M
KM
Seifalian
A M
AM
Goldspink
G
G
Winslet
M C
MC
D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D018076:DNA, Complementary / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000235:genetics* / Q000627:therapeutic use; D051379:Mice; D008819:Mice, Nude; D008938:Mitosis; D011485:Protein Binding