Title:Repurposing of Antidiarrheal Loperamide for Treating Melanoma by
Inducing Cell Apoptosis and Cell Metastasis Suppression In vitro and
In vivo
Volume: 24
Issue: 10
Author(s): Shuping Yang, Zhi Li, Mingyue Pan, Jing Ma, Zeyu Pan, Peng Zhang*Weiling Cao*
Affiliation:
- Department of Pharmacy, Shenzhen Luohu People’s Hospital, Shenzhen, Guangdong, China
- Department of Pharmacy, Shenzhen Luohu People’s Hospital, Shenzhen, Guangdong, China
Keywords:
Loperamide, melanoma, apoptosis, migration, invasion, drug repurposing.
Abstract:
Background: Melanoma is the most common skin tumor worldwide and still lacks effective
therapeutic agents in clinical practice. Repurposing of existing drugs for clinical tumor
treatment is an attractive and effective strategy. Loperamide is a commonly used anti-diarrheal
drug with excellent safety profiles. However, the affection and mechanism of loperamide in melanoma
remain unknown. Herein, the potential anti-melanoma effects and mechanism of loperamide
were investigated in vitro and in vivo.
Methods: In the present study, we demonstrated that loperamide possessed a strong inhibition in
cell viability and proliferation in melanoma using MTT, colony formation and EUD incorporation
assays. Meanwhile, xenograft tumor models were established to investigate the anti-melanoma activity
of loperamide
in vivo. Moreover, the effects of loperamide on apoptosis in melanoma cells
and potential mechanisms were explored by Annexin V-FITC apoptosis detection, cell cycle, mitochondrial
membrane potential assay, reactive oxygen species level detection, and apoptosis-correlation
proteins analysis. Furthermore, loperamide-suppressed melanoma metastasis was studied by
migration and invasion assays. What’s more, immunohistochemical and immunofluorescence
staining assays were applied to demonstrate the mechanism of loperamide against melanoma
in vivo.
Finally, we performed the analysis of routine blood and blood biochemical, as well as hematoxylin-
eosin (H&E) staining, in order to investigate the safety properties of loperamide.
Results: Loperamide could observably inhibit melanoma cell proliferation
in vitro and
in vivo.
Meanwhile, loperamide induced melanoma cell apoptosis by accumulation of the sub-G1 cells
population, enhancement of reactive oxygen species level, depletion of mitochondrial membrane
potential, and apoptosis-related protein activation
in vitro. Of note, apoptosis-inducing effects
were also observed in vivo. Subsequently, loperamide markedly restrained melanoma cell migration
and invasion
in vitro and
in vivo. Ultimately, loperamide was witnessed to have an amicable
safety profile.
Conclusion: These findings suggested that repurposing of loperamide might have great potential
as a novel and safe alternative strategy to cure melanoma
via inhibiting proliferation, inducing
apoptosis and cell cycle arrest, and suppressing migration and invasion.