To further corroborate these observations, we conducted an
analogous experiment in PC-3 cells, a model cell line for human
prostatic adenocarcinoma metastatic to bone (52). In PC-3 cells,
DA-ZP1-TPP correlated with MitoTracker Red qualitatively but
with a lower correlation coefficient (r = 0.32 ± 0.1) (SI Appendix,
Fig. S19). Consistent with the results for the RWPE cell line, PC-
3 cells showed no statistically significant increase in sensor
fluorescence intensity when bathed in zinc-enriched (50 μM
ZnCl2) RMPI 1640 medium with 10% FBS for 24 h before imaging
(Fig. 8).