Zebrafish Xenotransplant Cancer Model for Drug Screening - Zebrafish: Methods for Assessing Drug Safety and Toxicity - page 222

Figure 17.3 Drug effects on Xt Colo320 cells. Significantly lower chemiluminescence signal was
observed after treatment with 5-FU, oxaliplatin, and 5-FU þ leucovorin, indicating inhibition of Xt
Colo320 cell proliferation, whereas no effect was observed after treatment with camptothecin and
leucovorin. Data are presented as meanSE ( n ¼14). 0.24%, 0.4%, and 1% DMSO or water were
used as vehicle controls. Red bars indicate concentrations that caused statistically significant effects.
RCU, relative chemiluminescence units. indicates p <0.05 and indicates p <0.01. (See the color
version of this figure in Color Plates section.)

1000 M, LC 10 was not determined for 5-FU, oxaliplatin, and leucovorin. Based on

LC 10 estimations, three concentrations, 0.24, 0.12, and 0.06

m

m M, were assessed for

camptothecin, and 1000, 500, and 250 m M were assessed for oxaliplatin, leucovorin,

and 5-FU leucovorin combination.

Test drug was added to fish water immediately after xenotransplant. After
treatment for 3 days, zebrafish were processed for Xt ELISA using survivin
antibody. For all experiments, drug-treated Xt zebrafish were compared with vehicle
control, either DMSO or fish water, and results are shown in Fig. 17.3. Significant
inhibition ( P

þ

0.05) of Xt cancer cell proliferation was observed for 5-FU (3-43%
inhibition), oxaliplatin (3-60% inhibition), and 5-FU

<

leucovorin (22-31%
inhibition), and inhibition was dose dependent, whereas significant inhibition was
not observed for camptothecin. As expected, leucovorin alone did not inhibit Xt
cancer cell proliferation; however, 5-FU

þ

þ leucovorin combination caused

significant inhibition.
To further validate Xt ELISA, we compared cancer drug results in zebrafish with
results in humans. Overall prediction rate in Xt zebrafish was 80% (4/5) for Colo320
cells and 60% (3/5) for SW620 cells.

17.5 CONCLUSIONS

In vitro cell lines, including the NCI-60 human cancer cell lines, are extensively used
for primary drug screening; however, results using these invitro assays are significantly
different from results observed in complex, in vivo physiological environments.
Furthermore, xenotransplant rodent cancer models are laborious, time consuming,