Background and Aims: Niclosamide is an established anti-helminthic drug, which has recently
been shown to inhibit the growth of various cancer cells. To exploit the potential anti-tumor activity
of this drug for systemic use, the problem of low aqueous solubility should be addressed. The
present study tested the in vivo anti-tumor effects of a recently developed nanoliposomal preparation of
niclosamide in an experimental model of colon carcinoma.
Methods: The cytotoxicity of nanoliposomal niclosamide on CT26 colon carcinoma cells was evaluated
using the MTT test. Inhibition of tumor growth was investigated in BALB/c mice bearing CT26 colon
carcinoma cells. The animals were randomly divided into 4 groups including: 1) untreated control, 2)
liposomal doxorubicin (15 mg/kg; single intravenous dose), 3) liposomal niclosamide (1 mg/kg/twice a
week; intravenously for 4 weeks), and 4) free niclosamide (1 mg/kg/twice a week; intravenously for 4
weeks). To study therapeutic efficacy, tumor size and survival were monitored in 2-day intervals for 40
Results: In vitro results indicated that nanoliposomal and free niclosamide could exert cytotoxic effects
with IC50 values of 4.5 and 2.5 μM, respectively. According to in vivo studies, nanoliposomal niclosamide
showed a higher growth inhibitory activity against CT26 colon carcinoma cells compared
with free niclosamide as revealed by delayed tumor growth and prolongation of survival.
Conclusion: Nnaoliposomal encapsulation enhanced anti-tumor properties of niclosamide in an experimental
model of colon carcinoma.