Article Figures & Data
Figures
- Fig. 1.
Stat3 is activated in murine tumor cell lines. a, nuclear extracts prepared from the indicated mouse tumor cells and human U266 myeloma cells were incubated with the 32P-labeled hSIE oligonucleotide probe and analyzed by EMSA. b, nuclear extracts from B16 cells were preincubated with excess unlabeled hSIE (Lane 2) or FIRE (irrelevant oligonucleotide; Lane 3) probes and anti-Stat1 (Lane 5) or anti-Stat3 (Lane 6) antibodies to confirm specific Stat3 activation. Human myeloma U266 cells are used here as a positive control for Stat3 activation (17) . ST 3/3, Stat3 homodimers.
- Fig. 2.
Expression of Stat3β inhibits B16 tumor growth in vivo. a, β-gal staining of tumor cells electroinjected with the β-gal plasmid. Overall, 15% of the tumor cells were β-gal positive (semiquantitative analysis). Little or no staining was observed in the negative control (pcDNA3-transfected tumor section receiving the same staining; data not shown). b, summary of several independent Stat3β gene therapy experiments in vivo. Data shown represent the average tumor volumes in three experiments on the day when one or more animals in each experiment was sacrificed due to oversized or ulcerated tumors (on days 28, 20, and 22, respectively). A total of 15 control animals were treated with empty vector (▪), and 20 mice were treated with Stat3β (□), either pIRES-Stat3β or pAdCMV-Stat3β (*). For one representative experiment, growth kinetics of B16 tumors treated with either pIRES-EGFP (c) or pIRES-Stat3β (d) are shown. The first gene electroinjection was performed on day 8, when tumors reached an average diameter of 3–6 mm. Tumor measurements and the gene therapies indicated above were performed every 3–4 days. Four of five pIRES-Stat3β-treated tumors regressed.
- Fig. 3.
Gene therapy with Stat3β induces apoptosis in B16 tumors in vivo. H&E staining of B16 tumors treated with either the empty vector (a) or the Stat3β vector (b). TUNEL assay of the B16 tumors electroinjected with either the empty vector (c) or the Stat3β vector (d).
Tables
- Table 1
STAT3β kills B16 tumor cells but not normal NIH 3T3 fibroblasts
Transfectionefficiency (%) No. of G418r clonesa No. ofGFP-positive clones Cell lines Vector STAT3β Vector STAT3β Vector STAT3β B16 exp. 1b 68.7 81.7 21 0 11 0 B16 exp. 2 61.4 58.7 31 2 25 1 B16 exp. 3 36.6 41.3 112 23 74 5 B16 exp. 4 36.8 47.5 56 0 28 0 Sum 220 25 138 6 NIH 3T3 30.1 27.1 128 132 NDc ND -
a G418r, G418-resistant.
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b exp., experiment.
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c ND, not determined (no difference in GFP-positive clones was observed between the two groups).
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Volume 59, Issue 20
