Angewandte Chemie International Edition
10.1002/anie.202107347
RESEARCH ARTICLE
in the tumor volume during the 21-day period of treatment via intravenous
injection at a dosing frequency of every other day. The blue arrows indicate
the dosing time points. (d) Macroscopic views of xenograft tumors in the
different groups after 21 days of the indicated treatments. (e) Changes in the
body weight of xenografted mice during the 21-day period of treatment with
the different formulations indicated. The blue arrows indicate the dosing time
points. (f) Analysis of tumor and organ weights during the 21-day period of
treatment with the different formulations indicated via intravenous injection at a
dosing frequency of every other day. Immunohistochemistry of tumor tissues
in the different treatment groups. (g) Micrographs of tumor tissue sections with
Ki67 staining from the six treatment groups. (h) Micrographs of tumor tissue
sections with BRD4 staining from the six treatment groups. Scale bar, 200 µm.
In summary, a novel strategy for modifying PROTACs with an
aptamer was developed to overcome the limitations of
conventional PROTACs. We demonstrated for the first time that
aptamer conjugation facilitates the improvement of tumor
targeting specificity, leading to enhanced in vivo antitumor
activity and protein degradation and reduced toxicity. Thus, the
innovative APC technology established in this work has the
potential to improve the drug-likeness of conventional PROTACs.
Importantly, this aptamer modification strategy may have broad
applications in targeted protein degradation due to the
advantages of aptamers in precision medicine. Our future efforts
will be aimed at exploring diverse aptamers and designing new
types of linkers for better tumor tissue specificity and clinical
efficacy.
Effect of AS-modified conjugates on in vivo efficacy and
toxicity. Given the encouraging antitumor activity and targeted
distribution profiles, the in vivo antitumor efficacy of APR was
evaluated in the MCF-7 xenograft mouse model. When the
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tumors had an average volume of 150 mm after implantation,
Acknowledgements
mice were randomly divided into six groups. PBS or AS, CRO,
PRO, CPR or APR at a DNA dose of 10 μM (equal to a dose of
This work was supported by the National Natural Science
Foundation of China (grant 82030105 to C. S., 82003567 to S.
H., and 81725020 to C. S), the National Key Research and
Development Program of China (grant 2020YFA0509100 to C.
S.) and National Natural Science Foundation of Shanghai (grant
1
0 mg/kg for PRO) was administered intravenously every other
day. As shown in Figure 4c and 4d, PRO effectively inhibited
tumor growth and achieved a good tumor growth inhibition (TGI)
rate of 59.8% after 21 days of treatment. In contrast, CRO did
not exhibit antitumor activity in vivo. Interestingly, APR showed
excellent in vivo antitumor efficacy, with a TGI rate of 77.5%,
indicating that APR was significantly more potent than CPR (TGI
21ZR1422600 to F. G.).
=
20.2%) and AS (TGI = 28.8%) (Figure S5 in Supporting
Keywords: Aptamers • BET • Drug design • PROTAC • Tumor-
Information). In addition, the toxicity of APR in the xenograft
mouse model was further evaluated. The body weight of treated
mice was measured every 3 days during the treatment period
specific Targeting
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(Figure 4e). All compounds were well tolerated in the treated
[
[
[
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groups, without significant body weight loss and obvious
adverse effects. Next, the main organs of the treated mice were
weighed to evaluate toxicity (Figure 4f). There were no
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the different groups. Furthermore, H&E staining was used to
evaluate the toxicity of AS modifications (Figure S6 in
Supporting Information). Analysis of the H&E-stained sections
of major organs revealed severe lung lesions in xenografted
mice treated with PRO and CPR. In contrast, no significant
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performed better in inducing apoptosis than either control
compound (Figure 4g). The number of Ki67-stained cells in the
APR group was significantly lower than that in the other groups,
implying that APR had the best TGI efficacy. To further explore
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was performed using an anti-BRD4 antibody. As shown in
Figure 4h, compared with the blank control, compounds CRO
and AS led to only slight changes in BRD4 expression, while
BRD4 expression was significantly decreased in the PRO- and
APR-treated groups. Notably, APR more effectively decreased
the expression of BRD4 than PRO, suggesting that AS
modification enhanced BRD4 degradation in mice.
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