New Methodological Approach for the Rapid and Sensitive Detection of Melanocytes and Melanocytic Tumours

Abstract

Background: During melanogenesis, the activity of tyrosinase (the key enzyme for melanin synthesis) is important in the diagnosis of melanomas. Methods: Nine samples were included in this study, based on the availability of four malignant melanomas and five benign tumours. Our new approach is based on a combination of the DOPA oxidase and the glyoxylic acid (GA) methods for catecholamine (named the ‘DOPA-GA method’). Here, we compared the conventional DOPA oxidase method with that of the DOPA-GA method. Results: In all malignant melanomas, the fluorescence intensity of the DOPA-GA method was strongly expressed within the cytoplasm. The melanoma cells showed an obvious sensitivity compared with the Laidlaw and Blackberg method, as did the melanocytes in the normal skin. Detection was easier with the DOPA-GA method than the Laidlaw and Blackberg method. Hence, we developed a sensitive and rapid method with a total assay time of less than 30 min. Conclusion: DOPA-GA reflects tyrosinase activity in melanocytic tumours, and our new approach is an improvement on the conventional DOPA oxidase method, with regard to both specificity and sensitivity. The DOPA-GA method will be useful for routine pathological testing and melanogenetic studies of melanocytes and melanocytic tumours.

PM2.5 induces apoptosis, oxidative stress injury and melanin metabolic disorder in human melanocytes

“…Tyrosinase activity assay. Tyrosinase activity in PIG1 or PIG3V cells was measured with a DOPA oxidase method, as previously described (21). The cells were plated in a 6-well plate (at a cell density of 2x10 4 cells/ml) and exposed to PM2.5 (0-200 µg/ml) for 24 h. Then cells were washed with PBS three times, lysed with 1% Triton X-100 and centrifuged (16,000 x g) at room temperature for 15 min.…”

Wearable Wireless Tyrosinase Bandage and Microneedle Sensors: Toward Melanoma Screening

“…Due to the limitations of these methods, efforts have been devoted to faster and simpler detection of other melanoma biomarkers, such as the enzyme TYR. Tyrosinase is a polyphenol oxidase involved in the synthesis of melanin whose overexpression and accumulation in skin cells can lead to the formation of skin melanoma . TYR sensitivity approaches 100 percent for primary melanoma, with lower sensitivity in advanced stage of the disease.…”

Visual and Fluorescent Detection of Tyrosinase Activity by Using a Dual-Emission Ratiometric Fluorescence Probe

“…3,4 These reactions have been recognized as key processes in the biosynthetic pathway of some natural pigments. 1,5 So, TYR is considered to be a targeting enzyme for establishing treatments to several hypopigmentation-related problems. 6,7 Additionally, because of its major effect on dopamine neurotoxicity, TYR imbalance may also cause Parkinson's disease in association with neurodegeneration.…”

“…Tyrosinase (TYR), a typical polyphenol oxidase, is a copper-containing enzyme widely distributed in all kinds of organisms, such as plants, animal tissues, and fungi. , It can catalyze the hydroxylation of phenolic substrates to catechol derivatives, further oxidized to orthoquinone products. , These reactions have been recognized as key processes in the biosynthetic pathway of some natural pigments. , So, TYR is considered to be a targeting enzyme for establishing treatments to several hypopigmentation-related problems. , Additionally, because of its major effect on dopamine neurotoxicity, TYR imbalance may also cause Parkinson’s disease in association with neurodegeneration. , More importantly, the disruption of tyrosinase will lead to severe skin diseases such as oculocutaneous albinism type I, and accumulated tyrosinase is regarded as a dependable biomarker of melanoma cancer cells . Therefore, sensitive detection of tyrosinase activity is of great urgency to biomedical diagnosis.…”