Published in:
01-02-2013 | Original Article—Alimentary Tract
Conditionally replicative adenovirus-based mda-7/IL-24 expression enhances sensitivity of colon cancer cells to 5-fluorouracil and doxorubicin
Authors:
Jing Xu, Yiwo Mo, Xiaoyun Wang, Jun Liu, Xinjin Zhang, Junfeng Wang, Lei Hu, Chao Yang, Lei Chen, Yankun Wang
Published in:
Journal of Gastroenterology
|
Issue 2/2013
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Abstract
Background
Multiple drug resistance (MDR) greatly limits the efficacy of chemotherapy for colon cancer. An adenovirus armed with Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24; abbreviated to ‘IL-24’ here) was shown to reverse the MDR of colon cancer cells to oxaliplatin and doxorubicin. However, the relatively low expression level of IL-24 mediated by a replication-deficient adenoviral vector hindered its clinical application.
Methods
To enhance IL-24-dependentreversion of the MDR phenotype, we utilized a conditionally replicative adenoviral vector, AdBB-IL24, to express IL-24 at a high level for more efficient MDR reversion.
Results
An enzyme-linked immunosorbent assay (ELISA) suggested conditionally replicative adenoviral vector-mediated IL-24 expression was elevated in comparison with that of a replication-deficient adenoviral vector, Ad-IL24. AdBB-IL24 was shown to reverse MDR in colon cancer cells more potently than Ad-IL24. The AdBB-IL24-induced MDR reversion was linked to reduced P-glycoprotein (Pgp) and breast cancer resistance protein 1 (BCRP1) expression. Consistently, 5-fluorouracil and doxorubicin induced more apoptosis in AdBB-IL24-infected colon cancer cells compared with that in the Ad-IL24-infected cells. A cell viability assay showed that AdBB-IL24 could enhance the growth-inhibitory effect of 5-fluorouracil and doxorubicin on colon cancer cells more effectively than Ad-IL24 in vitro. In a mouse model, we also found that the combination of 5-fluorouracil and doxorubicin with AdBB-IL24 completely inhibited the growth of colon cancer cells.
Conclusion
We here provide evidence supporting conditionally replicative adenoviral vector-based gene therapy as a powerful strategy to enhance mda7/IL-24-dependent MDR reversion of colon cancer cells.