ROS-Mediated Therapeutic Strategy in Chemo-/Radiotherapy of Head and Neck Cancer

Table 1

The advantages and disadvantages of several ROS probes.

Name	Advantages	Disadvantages	Reference
DCFH-DA	Convenient to use	Photosensitivity and autoxidation; not specified to detect H2O2; oxidized by cytochrome c	[86, 87]
DHE	Convenient to use; specified to detect O2^-	Produces two products with similar fluorescence characteristics which need to be resolved by HPLC and other means; photosensitivity and autoxidation	[88]
DHR	Convenient to use; specified to detect ONOO^-	Intermediates can be reduced by mercaptan and vitamin C; autoxidation	[89]
FlAmBE	Convenient to use; stable fluorescence	Not specified to detect ONOO^-; high background fluorescence	[90]
HKSOX-1/1r	Specified to detect superoxide; stable fluorescence; specified to detect O2^-; insensitive to low pH	Not clear	[91]
MitoSOX	TPP group localized in mitochondria; convenient to use; specified to detect O2^-	Interferes with mitochondrial metabolism; mitochondrial membrane; potential-dependent location; produces two products with similar fluorescence characteristics which need to be resolved by HPLC; photosensitivity and autoxidation	[92]
MitoPY1	TPP group localized in mitochondria; convenient to use; stable fluorescence	Mitochondrial membrane potential-dependent location; not specified to detect ONOO^-; high background fluorescence	[93]
MitoAR/HR	Rhodamine group localized in mitochondria; convenient to use; specified to detect ·OH/HClO	Mitochondrial membrane potential-dependent location	[94]
HKSOX-1m	TPP group localized in mitochondria; specified to detect O2^-; stable fluorescence; insensitive to low pH	Mitochondrial membrane potential-dependent location	[91]
FRR2	Rhodamine group localized in mitochondria; convenient to use; reversible real-time detection; stable fluorescence	Nonspecific; mitochondrial membrane potential-dependent location	[95]
Pep1-NP	Cationic styrene localized in mitochondria; convenient to use; specified to detect H2O2; stable fluorescence	Not clear	[96]
Hyper	Highly specific to H2O2; reversible real-time detection; stable fluorescence; MLS group localized in subcellular structure; independent of membrane potential	pH sensitive; limitation of cell transfection efficiency	[97]
RoGFP2-Orp1	Highly specific to H2O2; reversible real-time detection; stable fluorescence; MLS group localized in subcellular structure; independent of membrane potential; pH insensitivity	Limitation of cell transfection efficiency	[98]

Note. DCFH-DA: 2,7-dichlorofluorescein diacetate; H₂O₂: hydrogen peroxide; DHE: dihydroethidium; O₂^-: superoxide anion radical; DHR: dihydrorhodamine; ONOO-: peroxynitrite anion; FlAmBE: boric acid ester derivative; HKSOX-1/1r/1m: novel O₂- probes using carboxy tetrafluorofluorescein as fluorescence group (HKSOX-1/1r for cellular retention, HKSOX-1m for mitochondria-targeting); pH: potential of hydrogen; MitoSOX: DHE for mitochondria-targeting; TPP: triphenyl-phosphine; HPLC: high-performance liquid chromatography; MitoPY1: FlAmBE for mitochondria-targeting; MitoAR/HR: DHR for mitochondria-targeting; ·OH: hydroxyl radical; HClO: hypochlorous acid; FRR2: a novel DHR probe; Pep1-NP: a novel boric acid probe targeting mitochondria; Hyper: a genetic probe specific for H₂O₂; RoGFP2-Orp1: redox-sensitive green fluorescent proteins 2; MLS: mitochondrial localization sequences.