Photodynamic therapy of melanoma by blue-light photoactivation of flavin mononucleotide

R A Akasov,A N Generalova,E V Khaydukov,A S Erofeev,D A Khochenkov,P V Gorelkin,A V Alova,N V Sholina

doi:10.1038/s41598-019-46115-w

Abstract

Melanoma is one of the most aggressive and lethal form of cancer. Photodynamic therapy (PDT) is a clinically approved technique for cancer treatment, including non-melanoma skin cancer. However, the most of conventional photosensitizers are of low efficacy against melanoma due to the possible dark toxicity at high drug concentrations, melanin pigmentation, and induction of anti-oxidant defense mechanisms. In the current research we propose non-toxic flavin mononucleotide (FMN), which is a water-soluble form of riboflavin (vitamin B2) as a promising agent for photodynamic therapy of melanoma. We demonstrated selective accumulation of FMN in melanoma cells in vivo and in vitro in comparison with keratinocytes and fibroblasts. Blue light irradiation with dose 5 J/cm2 of melanoma cells pre-incubated with FMN led to cell death through apoptosis. Thus, the IC50 values of human melanoma A375, Mel IL, and Mel Z cells were in a range of FMN concentration 10–30 µM that can be achieved in tumor tissue under systemic administration. The efficiency of reactive oxygen species (ROS) generation under FMN blue light irradiation was measured in single melanoma cells by a label-free technique using an electrochemical nanoprobe in a real-time control manner. Melanoma xenograft regression in mice was observed as a result of intravenous injection of FMN followed by blue-light irradiation of tumor site. The inhibition of tumor growth was 85–90% within 50 days after PDT treatment.

Highlights

Melanoma is one of the most aggressive and lethal form of cancer due to its metastasis capacity and acquired resistance to chemotherapy[1]
Five of six melanoma cell lines, namely Mel MTP, Mel IL, Mel Z, B16 F10, and M-3, accumulated more flavin mononucleotide (FMN) BJ-5ta fibroblasts (FMN range was 10–100 μM), while FMN accumulation in A375 cells was of similar level
Human melanoma cells Mel MTP, Mel IL, and Mel Z accumulated more FMN SK-BR-3 cells. All of these findings confirm the idea that FMN can be proposed for melanoma cells targeting

Summary

Introduction

Melanoma is one of the most aggressive and lethal form of cancer due to its metastasis capacity and acquired resistance to chemotherapy[1]. Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic procedure based on selective photosensitizer (PS) localization in neoplastic cells and vasculature with subsequent generation of reactive oxygen species (ROS) under light irradiation[11,12,13]. First type is direct transfer the energy from sensitizer to oxygen molecules dissolved in tissue and generation singlet oxygen toxic to cells. PDT was of limited efficacy against melanoma due to high dark toxicity of the most common photosensitizers, melanin pigmentation, and anti-oxidant defense mechanisms in melanoma cells. Photosensitizers like a chlorin e616 or verteporfin[17,18] have been shown as effective anti-melanoma agents in clinics, and a number of novel PSs are under laboratory investigations. Rf was proposed previously as an adjuvant for cisplatin therapy of skin cancer[26]

Methods

Results

Conclusion