TY - JOUR
T1 - Targeting HER-2/neu-overexpressing breast cancer cells by an antisense iron responsive element-directed gene expression
AU - Li, Zheng
AU - Xia, Weiya
AU - Fang, Bingliang
AU - Yan, Duen Hwa
N1 - Funding Information:
The authors would like to thank Dr Funda Meric for critical reading of the manuscript and Drs M.W. Hentze and M.-C. Hung for providing the reagents used in this study. This work was supported by a grant from Department of Defense (DAMD 17-99-1-9270) to D.-H.Y.
PY - 2001/12/28
Y1 - 2001/12/28
N2 - Overexpression of HER-2/neu proto-oncogene is found in many human cancers including 20-30% of breast cancer and is a predictor of poor prognosis. To target breast cancer cells that overexpress HER-2/neu mRNA, we previously described a novel strategy that combines the principle of antisense (AS) and translational inhibitory activity conferred by an iron-responsive element (IRE) (AS-IRE). Here, we showed that three potential AS-IREs, i.e. AS-IRE1, 4, and 5, derived from HER-2/neu antisense sequence could bind endogenous iron regulatory protein (IRP) and, when placed in 5′ untranslated region (5′UTR) of a reporter gene, the gene expression could be translationally repressed by recombinant IRP in vitro. Using AS-IRE4 as our model, we demonstrated that it is regulated by iron, and importantly, such regulation is impaired in HER-2/neu-overexpressing breast cancer cells. Furthermore, we showed that AS-IRE4 could preferentially direct the expression of a reporter gene in HER-2/neu-overexpressing breast cancer cells. Interestingly, when AS-IRE4 was placed in 5′UTR of Bax gene, a pro-apoptotic protein in the Bcl-2 protein family, we observed a preferential cell killing in breast cancer cells that overexpress HER-2/neu. Taken together, our results suggest that AS-IRE behaves as a functional IRE and it may direct therapeutic gene expression to preferentially target HER-2/neu-overexpressing breast cancer cells.
AB - Overexpression of HER-2/neu proto-oncogene is found in many human cancers including 20-30% of breast cancer and is a predictor of poor prognosis. To target breast cancer cells that overexpress HER-2/neu mRNA, we previously described a novel strategy that combines the principle of antisense (AS) and translational inhibitory activity conferred by an iron-responsive element (IRE) (AS-IRE). Here, we showed that three potential AS-IREs, i.e. AS-IRE1, 4, and 5, derived from HER-2/neu antisense sequence could bind endogenous iron regulatory protein (IRP) and, when placed in 5′ untranslated region (5′UTR) of a reporter gene, the gene expression could be translationally repressed by recombinant IRP in vitro. Using AS-IRE4 as our model, we demonstrated that it is regulated by iron, and importantly, such regulation is impaired in HER-2/neu-overexpressing breast cancer cells. Furthermore, we showed that AS-IRE4 could preferentially direct the expression of a reporter gene in HER-2/neu-overexpressing breast cancer cells. Interestingly, when AS-IRE4 was placed in 5′UTR of Bax gene, a pro-apoptotic protein in the Bcl-2 protein family, we observed a preferential cell killing in breast cancer cells that overexpress HER-2/neu. Taken together, our results suggest that AS-IRE behaves as a functional IRE and it may direct therapeutic gene expression to preferentially target HER-2/neu-overexpressing breast cancer cells.
KW - Antisense
KW - Bax
KW - Gene expression
KW - HER-2/neu
KW - Iron-responsive element
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U2 - 10.1016/S0304-3835(01)00700-5
DO - 10.1016/S0304-3835(01)00700-5
M3 - Article
C2 - 11689290
AN - SCOPUS:0035965946
SN - 0304-3835
VL - 174
SP - 151
EP - 158
JO - Cancer Letters
JF - Cancer Letters
IS - 2
ER -