Molecular and Biochemical Basis of Fluoroquinolones-Induced Phototoxicity-The Study of Antioxidant System in Human Melanocytes Exposed to UV-A Radiation

Current Insights into the Role of UV Radiation-Induced Oxidative Stress in Melanoma Pathogenesis

Cutaneous melanoma accounts for the majority of skin cancer-related deaths, and its incidence increases each year. The growing number of melanoma cases, especially in advanced stages, poses a significant socio-medical challenge throughout the world. Extensive research on melanoma pathogenesis identifies UV radiation as the most important factor in melanocytic transformation. Oxidative effects of UV irradiation exert their influence on melanoma pathogenesis primarily through modification of nucleic acids, proteins, and lipids, further disrupting cellular signaling and cell cycle regulation. Its effects extend beyond melanocytes, leading to immunosuppression in the exposed skin tissue, which consequently creates conditions for immune surveillance evasion and further progression. In this review, we focus on the specific molecular changes observed in the UV-dependent oxidative stress environment and their biological consequences in the course of the disease, which have not been considered in previous reviews on melanoma. Nonetheless, data show that the exact role of oxidative stress in melanoma initiation and progression remains unclear, as it affects cancerous cells differently depending on the specific context. A better understanding of the pathophysiological basis of melanoma development holds promise for identifying potential targets, which could lead to effective melanoma prevention strategies.

Intra-species differences shape differences of enrofloxacin residues and its degradation products in tilapia: A precise risk assessment

The increasing use and abuse of antibiotics in agriculture and aquaculture necessitates a more thorough risk assessment. We first advocate a precise assessment that subdivides the assessment scope from interspecies to intraspecific levels. Differences in ENR residues and degradation within the intraspecific category were simultaneously explored. This study chose red and GIFT tilapia, both belonging to the intra-specific category of tilapia, for an enrofloxacin (ENR) exposure experiment. Red tilapia had a lower area under the curve (AUC) representing drug accumulation, indicating a notably shorter withdrawal period (7 days) compared to GIFT tilapia (31.4 days) in the edible parts. While four potential transformation pathways were proposed for ENR in tilapia, red tilapia had fewer detected degradation products (6 items) than GIFT tilapia (10 items), indicating a simpler transformation pathway in red tilapia. Predictive assessments using the Toxtree model revealed that of the four extra degradation products in GIFT tilapia, two may possess carcinogenic and mutagenic properties. Overall, differences were observed in ENR residues and degradation within the intraspecific category, with red tilapia presenting lower risks than GIFT tilapia. This work suggests a new strategy to perfect the methodology for antibiotic risk assessment and facilitate systematic antibiotic administration management in the future.

Study of the impurity profile of photodegradation in lomefloxacin hydrochloride ear drops using liquid chromatography combined with ion trap/time-of-flight mass spectrometry

RATIONALE

Lomefloxacin hydrochloride ear drops are highly unstable to light and prone to produce photodegradation impurities. These impurities might be related to the phototoxicity of lomefloxacin, which could seriously threaten the health of patients. In this article, the photodegradation impurity profile in lomefloxacin hydrochloride ear drops was studied for further improvement of quality control of the drug.

METHODS

By studying the chromatographic behavior of photodegradation impurities, the photodegradation impurities in lomefloxacin hydrochloride ear drops were separated and detected effectively. Liquid chromatography combined with ion trap/time-of-flight mass spectrometry was applied to characterize the structures of the photodegradation impurities in lomefloxacin hydrochloride ear drops.

RESULTS

The structures of 17 impurities in lomefloxacin hydrochloride ear drops were elucidated based on high-resolution MSn data in positive ion mode, 12 of them being unknown impurities.

CONCLUSIONS

The structural characteristics and fragmentation patterns of the photodegradation impurities were also studied. The study of the photodegradation impurity profile in lomefloxacin hydrochloride ear drops provides a scientific basis for quality control of these ear drops and ensures the safety of drug use by the public.

Melanin Biopolymers in Pharmacology and Medicine-Skin Pigmentation Disorders, Implications for Drug Action, Adverse Effects and Therapy

Melanins are biopolymeric pigments formed by a multi-step oxidation process of tyrosine in highly specialized cells called melanocytes. Melanin pigments are mainly found in the skin, iris, hair follicles, and inner ear. The photoprotective properties of melanin biopolymers have been linked to their perinuclear localization to protect DNA, but their ability to scavenge metal ions and antioxidant properties has also been noted. Interactions between drugs and melanins are of clinical relevance. The formation of drug-melanin complexes can affect both the efficacy of pharmacotherapy and the occurrence of adverse effects such as phototoxic reactions and discoloration. Because the amount and type of melanin synthesized in the body is subject to multifactorial regulation-determined by both internal factors such as genetic predisposition, inflammation, and hormonal balance and external factors such as contact with allergens or exposure to UV radiation-different effects on the melanogenesis process can be observed. These factors can directly influence skin pigmentation disorders, resulting in hypopigmentation or hyperpigmentation of a genetic or acquired nature. In this review, we will present information on melanocyte biology, melanogenesis, and the multifactorial influence of melanin on pharmacological parameters during pharmacotherapy. In addition, the types of skin color disorders, with special emphasis on the process of their development, symptoms, and methods of treatment, are presented in this article.

Phototoxic action of meloxicam contributes to dysregulation of redox homeostasis in normal human skin cells - Molecular and biochemical analysis of antioxidant enzymes in melanocytes and fibroblasts

The phototoxic effect of meloxicam (MLX) raises the question of the effect of the drug on the redox homeostasis of normal human skin cells. The main objective of the study was to analyze the effect of MLX and/or UVA radiation (UVAR) on the redox homeostasis of human normal skin cells - melanocytes and fibroblasts. MLX was found to affect the activity and expression of enzymes of the antioxidant system differently depending on the cell line used. The drug decreased the activity and expression of superoxide dismutase type 1 and 2 (SOD1 and SOD2), catalase (CAT) and glutathione peroxidase (GPx) in fibroblasts, while increasing the activity of these enzymes in melanocytes. UVA radiation enhanced the effects of the drug. In conclusion, MLX in combination with UVAR induces oxidative stress in melanocytes and fibroblasts, however, the analyses showed that the drug's effect the activity and expression of SOD, CAT and GPx differently, depending on the cell line. The observed dissimilarity between tested cell lines may result from the presence of melanin pigments.

Phototoxic Reactions Inducted by Hydrochlorothiazide and Furosemide in Normal Skin Cells-In Vitro Studies on Melanocytes and Fibroblasts

Hypertension is known to be a multifactorial disease associated with abnormalities in neuroendocrine, metabolic, and hemodynamic systems. Poorly controlled hypertension causes more than one in eight premature deaths worldwide. Hydrochlorothiazide (HCT) and furosemide (FUR), being first-line drugs in the treatment of hypertension, are among others the most frequently prescribed drugs in the world. Currently, many pharmacoepidemiological data associate the use of these diuretics with an increased risk of adverse phototoxic reactions that may induce the development of melanoma and non-melanoma skin cancers. In this study, the cytotoxic and phototoxic potential of HCT and FUR against skin cells varied by melanin pigment content was assessed for the first time. The results showed that both drugs reduced the number of metabolically active normal skin cells in a dose-dependent manner. UVA irradiation significantly increased the cytotoxicity of HCT towards fibroblasts by approximately 40% and melanocytes by almost 20% compared to unirradiated cells. In the case of skin cells exposed to FUR and UVA radiation, an increase in cytotoxicity by approximately 30% for fibroblasts and 10% for melanocytes was observed. Simultaneous exposure of melanocytes and fibroblasts to HCT or FUR and UVAR caused a decrease in cell viability, and number, which was confirmed by microscopic assessment of morphology. The phototoxic effect of HCT and FUR was associated with the disturbance of redox homeostasis confirming the oxidative stress as a mechanism of phototoxic reaction. UVA-irradiated drugs increased the generation of ROS by 10-150%, and oxidized intracellular thiols. A reduction in mitochondrial potential of almost 80% in melanocytes exposed to HCT and UVAR and 60% in fibroblasts was found due to oxidative stress occurrence. In addition, HCT and FUR have been shown to disrupt the cell cycle of normal skin cells. Finally, it can be concluded that HCT is the drug with a stronger phototoxic effect, and fibroblasts turn out to be more sensitive cells to the phototoxic effect of tested drugs.

The research progress on the molecular mechanism of corneal cross-linking in keratoconus treatment

Keratoconus (KC) is a corneal anomaly that is manifested in a limited cone-like bulge with corneal thinning. Many molecules in the cornea change during the development of KC, including various components of the extracellular matrix, cytokines, cell connection, and cell adhesion-related proteins. Several treatment options are available, with corneal cross-linking (CXL) being the treatment of choice for early KC. However, postoperative complications have been reported in some CXL patients, mainly caused by corneal epithelial resection. Despite the fact that some novel approaches have helped to reduce some of the initial post-operative issues, their effectiveness seems to be inferior to that of the original CXL. To keep effectiveness while avoiding these negative effects, it is necessary to study the mechanism of CXL in KC treatment at the molecular level. This article provides a review of the molecular mechanism of CXL in the treatment of KC from four aspects: enzyme activity, signal transduction pathway, corneal-related proteins, and other KC-related molecules, further confirming the feasibility of CXL treatment of KC, providing new ideas for improving CXL.

Overview of Side-Effects of Antibacterial Fluoroquinolones: New Drugs versus Old Drugs, a Step Forward in the Safety Profile?

Antibacterial fluoroquinolones (FQs) are frequently used in treating infections. However, the value of FQs is debatable due to their association with severe adverse effects (AEs). The Food and Drug Administration (FDA) issued safety warnings concerning their side-effects in 2008, followed by the European Medicine Agency (EMA) and regulatory authorities from other countries. Severe AEs associated with some FQs have been reported, leading to their withdrawal from the market. New systemic FQs have been recently approved. The FDA and EMA approved delafloxacin. Additionally, lascufloxacin, levonadifloxacin, nemonoxacin, sitafloxacin, and zabofloxacin were approved in their origin countries. The relevant AEs of FQs and their mechanisms of occurrence have been approached. New systemic FQs present potent antibacterial activity against many resistant bacteria (including resistance to FQs). Generally, in clinical studies, the new FQs were well-tolerated with mild or moderate AEs. All the new FQs approved in the origin countries require more clinical studies to meet FDA or EMA requirements. Post-marketing surveillance will confirm or infirm the known safety profile of these new antibacterial drugs. The main AEs of the FQs class were addressed, highlighting the existing data for the recently approved ones. In addition, the general management of AEs when they occur and the rational use and caution of modern FQs were outlined.

Interaction between moxifloxacin and Mcl-1 and MITF proteins: the effect on growth inhibition and apoptosis in MDA-MB-231 human triple-negative breast cancer cells

Background

Microphthalmia-associated transcription factor (MITF) activates the expression of genes involved in cellular proliferation, DNA replication, and repair, whereas Mcl-1 is a member of the Bcl-2 family of proteins that promotes cell survival by preventing apoptosis. The objective of the present study was to verify whether the interaction between moxifloxacin (MFLX), one of the fluoroquinolones, and MITF/Mcl-1 protein, could affect the viability, proliferation, and apoptosis in human breast cancer using both in silico and in vitro models.

Methods

Molecular docking analysis (in silico), fluorescence image cytometry, and Western blot (in vitro) techniques were applied to assess the contribution of MITF and Mcl-1 proteins in the MFLX-induced anti-proliferative and pro-apoptotic effects on the MDA-MB-231 breast cancer cells.

Results

We indicated the ability of MFLX to form complexes with MITF and Mcl-1 as well as the drug’s capacity to affect the expression of the tested proteins. We also showed that MFLX decreased the viability and proliferation of MDA-MB-231 cells and induced apoptosis via the intrinsic death pathway. Moreover, the analysis of the cell cycle progression revealed that MFLX caused a block in the S and G2/M phases.

Conclusions

We demonstrated for the first time that the observed effects of MFLX on MDA-MB-231 breast cancer cells (growth inhibition and apoptosis induction) could be related to the drug’s ability to interact with MITF and Mcl-1 proteins. Furthermore, the presented results suggest that MITF and Mcl-1 proteins could be considered as the target in the therapy of breast cancer.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43440-022-00407-7.

The Assessment of Meloxicam Phototoxicity in Human Normal Skin Cells: In Vitro Studies on Dermal Fibroblasts and Epidermal Melanocytes

Meloxicam (MLX), which belongs to the oxicam nonsteroidal anti-inflammatory drug derivatives, is an inhibitor of the cyclooxygenase-2 (COX-2) enzyme. Cutaneous adverse effects caused by interaction between UVA radiation and exogenous factors can manifest as phototoxic reactions. Phototoxicity may be a reason for the accumulation of genetic and molecular changes in long-lived cells with low proliferation potential, leading to tumor development. There are several potentially phototoxic drugs, the active component of which is meloxicam. The research aimed to evaluate the influence of MLX and UVAR on skin cells—fibroblasts and melanocytes homeostasis. The obtained results indicated that co-treatment with MLX and UVAR inhibited skin cell proliferation, proportionally to the drug concentration. The observation was confirmed by cytometric analysis of the cell number and viability. The phototoxic effect of MLX was revealed in morphological changes. It was stated that MLX with UVAR lowered the mitochondrial transmembrane potential and changed the cell cycle profile. Additionally, MLX and UVAR caused the disruption of redox homeostasis by lowering the intracellular level of reduced thiols. The presented study revealed that the phototoxic activity of MLX is associated with oxidative stress induction and disruptions in cell homeostasis. The differences in the phototoxic effects of MLX at the cellular level may be related to the different content of melanin pigments.

Changes in the Oxidation-Reduction State of Human Dermal Fibroblasts as an Effect of Lomefloxacin Phototoxic Action

Phototoxicity induced by antibiotics is a real problem in health care. The discontinuation of antibiotic therapy due to a phototoxic reaction can lead to the development of resistant strains. Fluoroquinolones are widely used antibiotics that exhibit phototoxic activity under UVA radiation. The purpose of the study was to examine the redox status of human dermal fibroblasts exposed to UVA radiation and treated with lomefloxacin, the most phototoxic fluoroquinolone. Lomefloxacin alone was found to have an antiproliferative activity on fibroblasts by affecting the cell cycle. In addition, the drug caused a redox imbalance associated with the decreased expression of catalase and glutathione peroxidase. UVA radiation increased the drug cytotoxicity and oxidative stress induced by lomefloxacin. The decrease in cell viability was accompanied by a high level of reactive oxygen species and extensive changes in the antioxidant levels. The revealed data indicate that the phototoxic action of lomefloxacin results from both increased reactive oxygen species production and an impaired antioxidant defense system. Considering all of the findings, it can be concluded that lomefloxacin-induced phototoxic reactions are caused by an oxidoreductive imbalance in skin cells.

The Biochemical and Molecular Analysis of Changes in Melanogenesis Induced by UVA-Activated Fluoroquinolones-In Vitro Study on Human Normal Melanocytes

Fluoroquinolones cause phototoxic reactions, manifested as different types of skin lesions, including hyperpigmentation. The disturbances of melanogenesis indicate that fluoroquinolones may affect cellular processes in melanocytes. It has been reported that these antibiotics may bind with melanin and accumulate in pigmented cells. The study aimed to examine the changes in melanogenesis in human normal melanocytes exposed to UVA radiation and treated with lomefloxacin and moxifloxacin, the most and the least fluoroquinolone, respectively. The obtained results demonstrated that both tested fluoroquinolones inhibited melanogenesis through a decrease in tyrosinase activity and down-regulation of tyrosinase and microphthalmia-associated transcription factor production. Only lomefloxacin potentiated UVA-induced melanogenesis. Under UVA irradiation lomefloxacin significantly enhanced melanin content and tyrosinase activity in melanocytes, although the drug did not cause an increased expression of tyrosinase or microphthalmia-associated transcription factor. The current studies revealed that phototoxic activity of fluoroquinolones is associated with alterations in the melanogenesis process. The difference in phototoxic potential of fluoroquinolones derivatives may be connected with various effects on UVA-induced events at a cellular level.

Drug-Induced Photosensitivity-From Light and Chemistry to Biological Reactions and Clinical Symptoms

Photosensitivity is one of the most common cutaneous adverse drug reactions. There are two types of drug-induced photosensitivity: photoallergy and phototoxicity. Currently, the number of photosensitization cases is constantly increasing due to excessive exposure to sunlight, the aesthetic value of a tan, and the increasing number of photosensitizing substances in food, dietary supplements, and pharmaceutical and cosmetic products. The risk of photosensitivity reactions relates to several hundred externally and systemically administered drugs, including nonsteroidal anti-inflammatory, cardiovascular, psychotropic, antimicrobial, antihyperlipidemic, and antineoplastic drugs. Photosensitivity reactions often lead to hospitalization, additional treatment, medical management, decrease in patient's comfort, and the limitations of drug usage. Mechanisms of drug-induced photosensitivity are complex and are observed at a cellular, molecular, and biochemical level. Photoexcitation and photoconversion of drugs trigger multidirectional biological reactions, including oxidative stress, inflammation, and changes in melanin synthesis. These effects contribute to the appearance of the following symptoms: erythema, swelling, blisters, exudation, peeling, burning, itching, and hyperpigmentation of the skin. This article reviews in detail the chemical and biological basis of drug-induced photosensitivity. The following factors are considered: the chemical properties, the influence of individual ranges of sunlight, the presence of melanin biopolymers, and the defense mechanisms of particular types of tested cells.

Inhibitory Effect of Elaeagnus umbellata Fractions on Melanogenesis in α-MSH-Stimulated B16-F10 Melanoma Cells

When skin is exposed to UV radiation, melanocytes produce melanin. Excessive melanin production leads to skin pigmentation, which causes various cosmetic and health problems. Therefore, the development of safe, natural therapeutics that inhibit the production of melanin is necessary. Elaeagnus umbellata (EU) has long been widely used as a folk medicinal plant because of pharmacological properties that include anti-ulcer, antioxidant, and anti-inflammatory properties. In this study, we investigated the antioxidant activity and melanogenesis inhibitory effects of EU fractions in B16-F10 melanoma cells. EU fractions showed a dose-dependent increase in antioxidant activity in radical scavenging activity. In addition, we evaluated the effect of EU fractions on tyrosinase activity and melanogenesis in α-melanocyte-stimulating hormone-induced B16-F10 melanoma cells. EU was noncytotoxic at 12.5-50 μg/mL. EU fractions effectively inhibited tyrosinase activity and melanogenesis, suppressed the phosphorylation of CREB and ERK involved in the melanogenesis pathway, and down-regulated expression of melanogenesis-related proteins. Interestingly, the anti-melanogenesis effect was most effective at a concentration of 50 μg/mL EU, and the effects of the fractions were superior to those of the extract. Therefore, our study suggests that EU has potential as a safe treatment for excessive pigmentation or as a natural ingredient in cosmetics.