Communication
ChemComm
We thank Jenna Klubnick for synthesis of 4-(4-fluoro-3-
(piperazine-1-carbonyl)benzyl)phthalazin-1(2H)-one and Alex
Zaltsman for assistance in imaging. This work was supported
in part by the National Institutes of Health (NIH) grants
1R01CA164448, P01CA139980 and P50CA086355 (R.W.). K. Y.
and R. G. were supported by NIH grant T32CA079443.
Notes and references
1 M. Vendrell, D. Zhai, J. C. Er and Y. T. Chang, Chem. Rev., 2012,
112, 4391.
2 T. Reiner, J. Lacy, E. J. Keliher, K. S. Yang, A. Ullal, R. H. Kohler,
C. Vinegoni and R. Weissleder, Neoplasia, 2012, 14, 169.
3 G. M. Thurber, K. S. Yang, T. Reiner, R. H. Kohler, P. Sorger,
T. Mitchison and R. Weissleder, Nat. Commun., 2013, 4, 1504.
4 K. S. Yang, G. Budin, T. Reiner, C. Vinegoni and R. Weissleder,
Angew. Chem., Int. Ed., 2012, 51, 6598.
5 Y. Koide, Y. Urano, K. Hanaoka, T. Terai and T. Nagano, ACS Chem.
Biol., 2011, 6, 600.
6 G. Lukinavicius, et al., Nat. Chem., 2013, 5, 132.
7 T. Egawa, K. Hanaoka, Y. Koide, S. Ujita, N. Takahashi, Y. Ikegaya,
N. Matsuki, T. Terai, T. Ueno, T. Komatsu and T. Nagano, J. Am.
Chem. Soc., 2011, 133, 14157.
Fig. 3 Colocalization of 14 with PARP1. (A) Live cell imaging of MDA-MB-231
cells (expressing PARP1 fused to GFP) with 10 mM 14. (a) PARP1-GFP cellular
localization, (b) 14, (c) merged image showing colocalization between PARP1-
GFP and 14. Scale bar: 10 mm. (B) Colocalization scatter plot of representative
cell (dotted circle) and table of Pearson and Manders correlation coefficients.
8 K. A. Menear, et al., J. Med. Chem., 2008, 51, 6581.
9 S. Desnoyers, S. H. Kaufmann and G. G. Poirier, Exp. Cell Res., 1996,
227, 146.
10 O. Mortusewicz, J. C. Ame, V. Schreiber and H. Leonhardt, Nucleic
Acids Res., 2007, 35, 7665.
11 S. Vyas, M. Chesarone-Cataldo, T. Todorova, Y. H. Huang and
P. Chang, Nat. Commun., 2013, 4, 2240.
12 J. D. Orth, R. H. Kohler, F. Foijer, P. K. Sorger, R. Weissleder and
T. J. Mitchison, Cancer Res., 2011, 71, 4608.
13 T. Reiner, S. Earley, A. Turetsky and R. Weissleder, ChemBioChem,
2010, 11, 2374.
14 M. Poot, Y. Z. Zhang, J. A. Kramer, K. S. Wells, L. J. Jones,
D. K. Hanzel, A. G. Lugade, V. L. Singer and R. P. Haugland,
J. Histochem. Cytochem., 1996, 44, 1363.
attribute this to the positive charge, an observation that has in
retrospect also been made for other fluorochromes (such as
rhodamine 123). In contradistinction and support of this observa-
tion, elimination of the charge by carboxylation, abrogated the
mitochondrial phenotype and the drug fluorochrome conjugate
showed a ubiquitous cellular distribution. Finally, introduction of a
small spacer further improved cellular distribution and presumably
target binding, as shown by co-localization and affinity studies with
the Olaparib-conjugated CID and PARP1.
The current study focused on the PARP inhibitor Olaparib as 15 L. V. Johnson, M. L. Walsh and L. B. Chen, Proc. Natl. Acad. Sci. U. S. A.,
1980, 77, 990.
a proof-of-principle of cellular nuclear targeting. However, we
envision similar strategies to be applicable the growing number
16 E. M. M. Manders, F. J. Verbeek and J. A. Aten, J. Microsc., 1993, 169, 375.
The Pearson’s correlation coefficient is a standard method of image
of kinase inhibitors and other small molecule drugs. Such labeled
companion imaging drugs are expected to be valuable com-
pounds for imaging pharmacokinetics and pharmacodynamics
at the single cell level in vivo.3
correlation, with output values ranging from ꢁ1 to 1, where 1 indicates a
perfect correlation between two channels, ꢁ1 indicates a perfect negative
correlation and 0 indicates random correlation. Mander’s coefficients,
M1 and M2, measures overlap with value ranges between 0 and 1, where
1 indicates a perfect colocalization and 0 indicates no colocalization.
This journal is ©The Royal Society of Chemistry 2014
Chem. Commun., 2014, 50, 4504--4507 | 4507