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Betulonic acid (B(O)A) is a pentacyclic lupane-type triterpenoid that widely exists in plants. There are scientific reports indicating anticancer activity of B(O)A, as well as the amides and esters of this triterpenoid. In the first step of the study, the synthesis of novel amide derivatives of B(O)A containing an acetylenic moiety was developed. Subsequently, the medium-soluble compounds (EB171 and EB173) and the parent compound, i.e., B(O)A, were investigated for potential cytotoxic activity against breast cancer (MCF-7 and MDA-MB-231) and melanoma (C32, COLO 829 and A375) cell lines, as well as normal human fibroblasts. Screening analysis using the WST-1 test was applied. Moreover, the lipophilicity and ADME parameters of the obtained derivatives were determined using experimental and in silico methods. The toxicity assay using zebrafish embryos and larvae was also performed. The study showed that the compound EB171 exhibited a significant cytotoxic effect on cancer cell lines: MCF-7, A-375 and COLO 829, while it did not affect the survival of normal cells. Moreover, studies on embryos and larvae showed no toxicity of EB171 in an animal model. Compared to EB171, the compound EB173 had a weaker effect on all tested cancer cell lines and produced less desirable effects against normal cells. The results of the WST-1 assay obtained for B(O)A revealed its strong cytotoxic activity on the examined cancer cell lines, but also on normal cells. In conclusion, this article describes new derivatives of betulonic acid—from synthesis to biological properties. The results allowed to indicate a promising direction for the functionalization of B(O)A to obtain derivatives with selective anticancer activity and low toxicity. [ABSTRACT FROM AUTHOR]

Cancer cells need to carefully regulate their metabolism to keep them growing and dividing under the influence of different nutrients and oxygen levels. Muscle isoform 2 of pyruvate kinase (PKM2) is a key glycolytic enzyme involved in the generation of ATP and is critical for cancer metabolism. PKM2 is expressed in many human tumors and is regulated by complex mechanisms that promote tumor growth and proliferation. Therefore, it is considered an attractive therapeutic target for modulating tumor metabolism. Various modulators regulate PKM2, shifting it between highly active and less active states. In the presented work, a series of 8-quinolinesulfonamide derivatives of PKM2 modulators were designed using molecular docking and molecular dynamics techniques. New compounds were synthesized using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Compound 9a was identified in in silico studies as a potent modulator of muscle isoform 2 of pyruvate kinase. The results obtained from in vitro experiments confirmed the ability of compound 9a to reduce the intracellular pyruvate level in A549 lung cancer cells with simultaneous impact on cancer cell viability and cell-cycle phase distribution. Moreover, compound 9a exhibited more cytotoxicity on cancer cells than normal cells, pointing to high selectivity in the mode of action. These findings indicate that the introduction of another quinolinyl fragment to the modulator molecule may have a significant impact on pyruvate levels in cancer cells and provides further directions for future research to find novel analogs suitable for clinical applications in cancer treatment. [ABSTRACT FROM AUTHOR]

Melanoma is still one of the most dangerous cancers. New methods of treatment are sought due to its high aggressiveness and the relatively low effectiveness of therapies. Tetracyclines are drugs exhibiting anticancer activity. Previous studies have also shown their activity against melanoma cells. The possibility of tetracycline accumulation in pigmented tissues and the increase in their toxicity under the influence of UVA radiation creates the possibility of developing a new anti-melanoma therapy. This study aimed to analyze the phototoxic effect of doxycycline and chlortetracycline on melanotic melanoma cells COLO 829 and G-361. The results indicated that tetracycline-induced phototoxicity significantly decreased the number of live cells by cell cycle arrest as well as a decrease in cell viability. The simultaneous exposure of cells to drugs and UVA caused the depolarization of mitochondria as well as inducing oxidative stress and apoptosis. It was found that the combined treatment activated initiator and effector caspases, caused DNA fragmentation and elevated p53 level. Finally, it was concluded that doxycycline demonstrated a stronger cytotoxic and phototoxic effect. UVA irradiation of melanoma cells treated with doxycycline and chlortetracycline allows for the reduction of therapeutic drug concentrations and increases the effectiveness of tested tetracyclines. [ABSTRACT FROM AUTHOR]

Pentacyclic triterpenes, including betulin, are widespread natural products with various pharmacological effects. These compounds are the starting material for the synthesis of substances with promising anticancer activity. The chemical modification of the betulin scaffold that was carried out as part of the research consisted of introducing the indole moiety at the C-28 position. The synthesized new 28-indole-betulin derivatives were evaluated for anticancer activity against seven human cancer lines (A549, MDA-MB-231, MCF-7, DLD-1, HT-29, A375, and C32). It was observed that MCF-7 breast cancer cells were most sensitive to the action of the 28-indole-betulin derivatives. The study shows that the lup-20(29)-ene-3-ol-28-yl 2-(1H-indol-3-yl)acetate caused the MCF-7 cells to arrest in the G1 phase, preventing the cells from entering the S phase. The performed cytometric analysis of DNA fragmentation indicates that the mechanism of EB355A action on the MCF-7 cell line is related to the induction of apoptosis. An in silico ADMET profile analysis of EB355A and EB365 showed that both compounds are bioactive molecules characterized by good intestinal absorption. In addition, the in silico studies indicate that the 28-indole-betulin derivatives are substances of relatively low toxicity. [ABSTRACT FROM AUTHOR]

Cobalamin (vitamin B12) deficiency is one of the major factors causing degenerative changes in the nervous system and, thus, various neurological and psychiatric symptoms. The underlying cellular mechanism of this phenomenon is not yet fully understood. An accumulation of senescent astrocytes has been shown to contribute to a wide range of pathologies of the nervous system, including neurodegenerative disorders. This study aimed to investigate whether cobalamin deficiency triggers astrosenescence. After inducing cobalamin deficiency in normal human astrocytes in vitro, we examined biomarkers of cellular senescence: SA-β-gal, p16INK4A, and p21Waf1/Cip1 and performed cell nuclei measurements. The obtained results may contribute to an increase in the knowledge of the cellular effects of cobalamin deficiency in the context of astrocytes. In addition, the presented data suggest a potential causative agent of astrosenescence that has not been proven to date. [ABSTRACT FROM AUTHOR]

Streptomycin (STR) is an aminoglycoside antibiotic with a broad-spectrum of activity and ototoxic potential. The mechanism of STR-induced inner ear damage has not been fully elucidated. It was previously found that STR binds to melanin, which may result in the accumulation of the drug in melanin-containing tissues. Melanin pigment is present in various parts of the inner ear, including the cochlea and vestibular organ. The present study aimed to assess if streptomycin generates oxidative stress and affects melanogenesis in normal human melanocytes. Moreover the variation of free radical concentration in STR-treated melanocytes was examined by electron paramagnetic resonance spectroscopy (EPR). We found that STR decreases cell metabolic activity and reduces melanin content. The observed changes in the activity of antioxidant enzymes activity in HEMn-DPs treated with streptomycin may suggest that the drug affects redox homeostasis in melanocytes. In this work EPR study expanded knowledge about free radicals in interactions of STR and melanin in melanocytes. The results may help elucidate the mechanisms of STR toxicity on pigment cells, including melanin-producing cells in the inner ear. This is important because understanding the mechanism of STR-induced ototoxicity would be helpful in developing new therapeutic strategies to protect patients' hearing. • Streptomycin decreases metabolic activity and reduces melanin in melanocytes. • Streptomycin affects antioxidant enzymes in melanocytes. • Free radicals participate in streptomycin interactions with pigmented cells. • Melanin may protect pigment cells from adverse effects of streptomycin. [ABSTRACT FROM AUTHOR]

Cobalamin (vitamin B12) is a water-soluble organic compound that belongs to the B group of vitamins. Because of the complex structure and polarity of vitamin B12 molecule, its proper use and transformation in the human organism require the participation of specialized proteins. The main source of cobalamin for humans is food of animal origin. Due to tissue cobalamin reserves, the symptoms of its deficiency occur after several years of insufficient food supply. However, screening for cobalamin deficiency is reasonable in people with hypocobalaminemia risk factors such as gastric or small intestinal resection, vegan diet, long-term use of metformin, histamine H2-receptor antagonists, and proton pump inhibitors, as well as old age. Vitamin B12 as an enzyme cofactor participates in numerous intra-mitochondrial reactions and in the synthesis of methionine, which is necessary for the formation of S-adenosylmethionine, an important factor in the process of methylation of biological molecules. Through metabolic links with folic acid, cobalamin affects DNA synthesis and cell division. Currently, more and more attention is paid to the potential contribution of vitamin B12 deficiency in the pathogenesis of neurodegenerative diseases and cancers. At the molecular level, cobalamin deficiency leads to the destabilization of cellular genome, which increases the risk of malignant transformation. On the other hand, in people with cancer or at high risk of developing it, vitamin B12 may increase the expansion of neoplastic cells. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract Tetracyclines belong to antimicrobial classes with the highest consumption in veterinary medicine and agriculture, which leads to the contamination of the environment and food products, as well as to antibiotic resistance and adverse drug reactions. Chloro-derivatives of tetracyclines are thought to be relatively more phototoxic than others and belong to the most frequently cited drugs as photosensitizers. Melanins are heterogenous biopolymers determining skin, hair and eye colour. They are biosynthesized in a multistep process in melanocytes. Melanins, besides photoprotective and antioxidant properties, may also contribute to adverse skin drug reactions, which involve e.g. hyperpigmentation disorders and phototoxic reactions. Furthermore, they have the ability to form a drug-melanin complex, which leads to deposition of the drug or its metabolites in pigmented tissues. The aim of the study was to examine the ability of chlortetracycline to form a complex with melanin, as well as the effect of the drug on viability, antioxidant defence system and melanogenesis in normal human epidermal melanocytes exposed to the UVA radiation. The obtained results show for the first time that chlortetracycline forms a complex with melanin polymers, which creates a possibility of the drug accumulation in pigmented tissues. A simultaneous exposition of normal melanocytes to chlortetracycline and to the UVA radiation decreases cell viability, proportionally to the drug concentration and the irradiation time. The phototoxic effect appears to be related to the induction of oxidative stress in melanocytes, mainly through an increase of SOD and a decrease of the CAT activity. Chlortetracycline itself does not influence the melanin content or the activity of tyrosinase. The UVA radiation appeared to be a conditioning factor stimulating melanogenesis, whereas the presence of the drug augmented this effect. Graphical abstract Image 1 Highlights • Chlortetracycline forms a complex with melanin polymers. • Chlortetracycline causes concentration-dependent decreases in melanocyte viability. • Chlortetracycline and UVA irradiation induces oxidative stress in melanocytes. • Chlortetracycline doesn't induce melanin synthesis in cells unexposed to UVA. • The phototoxicity of chlortetracycline manifests in the induction of melanogenesis. [ABSTRACT FROM AUTHOR]

Abstract Fluoroquinolones were shown to be cytotoxic towards various cancer cell lines, thus representing a potentially important source of new anticancer agents. The aim of the present study was to examine the effect of moxifloxacin on cell viability, redox balance and apoptosis in both amelanotic – C32 and melanotic – COLO829 melanoma cells. Herein, we found that moxifloxacin decreases the viability of C32 and COLO829 cells in concentration- and time-dependent manner. The EC 50 values were found to be as 0.16 mM, 0.12 mM and 0.11 mM for amelanotic C32 cells as well as 0.40 mM, 0.22 mM and 0.15 mM for COLO829 cells and 24, 48, 72 h incubation time, respectively. Moxifloxacin have also induced the intracellular disulphide imbalance and apoptosis as shown by externalization of phosphatidylserine, caspase-3/7 activation, G 2 /M cell cycle arrest and DNA fragmentation. The mechanism of apoptosis was related to the loss of mitochondrial membrane potential. This is the first study that characterized cellular and molecular mechanism underlying moxifloxacin cytotoxic and pro-apoptotic effect towards melanoma cells. Although further studies are required to establish efficacy of moxifloxacin against melanoma in clinical practice, the results of current study strongly suggest, that moxifloxacin is promising candidate as a repositioned drug for anti-melanoma treatment. Graphical abstract Unlabelled Image Highlights • Moxifloxacin reduces the viability of C32 and COLO829 melanoma cells. • The drug induces intracellular disulphide imbalance. • Moxifloxacin induces apoptosis in amelanotic as well as melanotic melanoma cells. • Exposure of C32 and COLO829 cells to moxifloxacin causes DNA fragmentation. [ABSTRACT FROM AUTHOR]

Cancers are a significant health problem in the world. The most common therapeutic methods applied in oncology are chemotherapy, radiotherapy and surgical methods. Finding new therapies in this branch of medicine, as well as developing solutions with the highest possible effectiveness, taking into account the multifactorial nature of cancer, is important from both the scientific and medical point of view and, for obvious reasons, it is in the interest of many people. Immunotherapy, despite many years of initial failures, has become one of the most important clinically approved new treatments in oncology and is now successfully used in the treatment of certain types of cancer. Current immunotherapeutic strategies are based on monoclonal antibodies (including inhibitors of immune control points), cytokines, anti-cancer vaccines, oncolytic viruses, as well as adoptive cell transfer. For many cancer immunotherapies, an increase in their effectiveness is observed when they are used with other types of immunotherapy as well as in combination with molecular targeted therapy, chemotherapy or radiotherapy. The dynamic development of cancer immunotherapy since the beginning of the 21st century results from the advances in genetic engineering, as well as from the increase in knowledge about the anticancer immune response and the nature of cancer cells including abnormalities in their metabolism, the ability to create a tumor microenvironment and the induction of immunosuppression. The aim of the study is to present current knowledge in the field of cancer immunotherapy strategies. [ABSTRACT FROM AUTHOR]

Abstract Coffee is one of the most popular beverages consumed worldwide and therefore even small effects of coffee bioactive compounds on cellular homeostasis could have a large impact on public health. Recent cohort health studies have shown an impressive inverse correlation between caffeinated coffee consumption and malignant melanoma risk. The aim of presented study was to examine the effect of caffeine on cell viability and glutathione status of melanotic (COLO829) and amelanotic (C32) melanoma cell lines as well as normal human melanocytes. Cell viability was determined by WST-1 colorimetric assay and then confirmed by the cytometry analysis with NucleoCounter® NC-3000™. The intracellular level of reduced thiols was determined by the use of the fluorescence-based image cytometer. The obtained results indicate the ability of caffeine to induce reduced thiols depletion and pro-apoptotic effect selectively in melanoma cells. The COLO829 cell line was shown to be more susceptible to studied methylxanthine in comparison to C32 cells. These data may support, for the first time, the recent epidemiological studies and provide the basis for further research into the mechanism of chemopreventive properties of caffeine. Highlights • Caffeine causes the decrease in melanoma cells viability. • Caffeine induces loss of reduced thiols level in melanoma cells. • The COLO829 cell line was shown to be more susceptible to caffeine than C32 cells. • Caffeine does not affect normal melanocytes homeostasis. [ABSTRACT FROM AUTHOR]

Fluoroquinolones are a known synthetic group of antibiotics that have been the subject of many research interests. This class of antibiotics was shown to be cytotoxic towards various cancer cell lines, thus representing a potentially important source of new anticancer agents. The present study was designed to examine the effect of ciprofloxacin and moxifloxacin on cell viability, redox balance and apoptosis in U87MG glioblastoma cells. Herein, we found that both fluoroquinolones decrease the viability and exert an anti-proliferative effect on U87MG cells. The EC 50 values were found to be as 0.75 µmol/ml, 0.57 µmol/ml, 0.53 µmol/ml for ciprofloxacin and 24, 48, 72 h incubation time, respectively, and 0.48 µmol/ml, 0.22 µmol/ml, 0.15 µmol/ml for moxifloxacin and 24, 48, 72 h incubation time, respectively. Ciprofloxacin and moxifloxacin have also induced the intracellular GSH depletion and apoptosis as shown by externalization of phosphatidylserine, caspase-3/7 activation, S and sub-G 1 cell cycle arrest, nuclear morphological changes induction and DNA fragmentation. The mechanism of apoptosis was related to the loss of mitochondrial membrane potential suggesting activation of the intrinsic mitochondrial pathway. This is the first study that may provide the basis for understanding potential cellular and molecular mechanism underlying ciprofloxacin and moxifloxacin cytotoxic and pro-apoptotic effect towards U87MG glioblastoma cells, suggesting that these fluoroquinolone derivatives may have value for the development as anti-glioma agents. [ABSTRACT FROM AUTHOR]

Melanins are natural pigments of skin, hair and eyes and can be classified into two main types: brown to black eumelanin and yellow to reddish-brown pheomelanin. Biosynthesis of melanins takes place in melanosomes, which are specialized cytoplasmic organelles of melanocytes - dendritic cells located in the basal layer of the epidermis, uveal tract of the eye, hair follicles, as well as in the inner ear, central nervous system and heart. Melanogenesis is a multistep process and begins with the conversion of amino acid L-tyrosine to DOPAquinone. The addition of cysteine or glutathione to DOPAquinone leads to the intermediates formation, followed by subsequent transformations and polymerization to the final product, pheomelanin. In the absence of thiol compounds DOPAquinone undergoes an intramolecular cyclization and oxidation to form DOPAchrome, which is then converted to 5,6-dihydroksyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Eumelanin is formed by polymerization of DHI and DHICA and their quinones. Regulation of melanogenesis is achieved by physical and biochemical factors. The article presents the intracellular signaling pathways: cAMP/PKA/CREB/MITF cascade, MAP kinases cascade, PLC/DAG/PKCß cascade and NO/cGMP/PKG cascade, which are involved in the regulation of expression and activity of the melanogenesis-related proteins by ultraviolet radiation and endogenous agents (cytokines, hormones). Activity of the key melanogenic enzyme, tyrosinase, is also affected by pH and temperature. Many pharmacologically active substances are able to inhibit or stimulate melanin biosynthesis, as evidenced by in vitro studies on cultured pigment cells. [ABSTRACT FROM AUTHOR]

High mortality, aggressiveness, and the relatively low effectiveness of therapy make melanoma the most dangerous of skin cancers. Previously published studies presented the promising therapeutic potential of minocycline, doxycycline, and chlortetracycline on melanoma cells. This study aimed to assess the cytotoxicity of tigecycline, a third-generation tetracycline, on melanotic (COLO 829) and amelanotic (A375) melanoma cell lines. The obtained results showed that tigecycline, proportionally to the concentration and incubation time, efficiently inhibited proliferation of both types of melanoma cells. The effect was accompanied by the dysregulation of the cell cycle, the depolarization of the mitochondrial membrane, and a decrease in the reduced thiols and the levels of MITF and p44/42 MAPK. However, the ability to induce apoptosis was only found in COLO 829 melanoma cells. A375 cells appeared to be more resistant to the treatment with tigecycline. The drug did not induce apoptosis but caused an increase in LC3A/B protein levels—an autophagy marker. The observed differences in drug action on the tested cell lines also involved an increase in p21 and p16 protein levels in melanotic melanoma, which was related to cell cycle arrest in the G1/G0 phase. The greater sensitivity of melanotic melanoma cells to the action of tigecycline suggests the possibility of considering the use of the drug in targeted therapy. [ABSTRACT FROM AUTHOR]

Malignant melanoma is still a serious medical problem. Relatively high mortality, a still-growing number of newly diagnosed cases, and insufficiently effective methods of therapy necessitate melanoma research. Tetracyclines are compounds with pleiotropic pharmacological properties. Previously published studies on melanotic melanoma cells ascertained that minocycline and doxycycline exerted an anti-melanoma effect. The purpose of the study was to assess the anti-melanoma potential and mechanisms of action of minocycline and doxycycline using A375 and C32 human amelanotic melanoma cell lines. The obtained results indicate that the tested drugs inhibited proliferation, decreased cell viability, and induced apoptosis in amelanotic melanoma cells. The treatment caused changes in the cell cycle profile and decreased the intracellular level of reduced thiols and mitochondrial membrane potential. The exposure of A375 and C32 cells to minocycline and doxycycline triggered the release of cytochrome c and activated initiator and effector caspases. The anti-melanoma effect of analyzed drugs appeared to be related to the up-regulation of ERK1/2 and MITF. Moreover, it was noticed that minocycline and doxycycline increased the level of LC3A/B, an autophagy marker, in A375 cells. In summary, the study showed the pleiotropic anti-cancer action of minocycline and doxycycline against amelanotic melanoma cells. Considering all results, it could be concluded that doxycycline was a more potent drug than minocycline. [ABSTRACT FROM AUTHOR]

Despite many advances in therapy, glioblastoma (GB) is still characterized by its poor prognosis. The main reason for this is unsuccessful treatment, which slightly extends the duration of remission; thus, new regimens are needed. One of many types of chemotherapeutics that are being investigated in this field is topoisomerase inhibitors, mainly in combination therapy with other drugs. On the other hand, the search for new anti-cancer substances continues. Neobavaisoflavone (NBIF) is a natural compound isolated from Psoralea corylifolia L., which possesses anti-oxidant, anti-inflammatory, and anti-cancer properties. The aim of this study was to evaluate the effect of NBIF in human U-87 MG glioblastoma cells in comparison to normal human NHA astrocytes, and to examine if it influences the activity of irinotecan, etoposide, and doxorubicin in this in vitro model. We demonstrated that NBIF decreases U-87 MG cells viability in a dose-dependent manner. Furthermore, we found that it inhibits cell growth and causes glutathione (GSH) depletion more intensely in U-87 MG cells than in astrocytes. This study also provides, for the first time, evidence of the potentialization of the doxorubicin effect by NBIF, which was shown by the reduction in the viability in U-87 MG cells. [ABSTRACT FROM AUTHOR]

As part of the search for new medicinal substances with potential application in oncology, the synthesis of new compounds combining the betulin molecule and the indole system was carried out. The structure of the ester derivatives obtained in the Steglich reaction was confirmed by spectroscopic methods (1H and 13C NMR, HR-MS). The obtained new 3-indolyl betulin derivatives were evaluated for anticancer activity against several human cancer cell lines (melanomas, breast cancers, colorectal adenocarcinomas, lung cancer) as well as normal human fibroblasts. The significant reduction in MCF-7 cells viability for 28-hydroxy-(lup-20(29)-ene)-3-yl 2-(1H-indol-3-yl)acetate was observed at a concentration of 10 µg/mL (17 µM). In addition, cytometric analysis showed that this compound strongly reduces the proliferation rate of breast cancer cells. For this, the derivative showing the promising cytotoxic effect on MCF-7 breast cancer cells, the pharmacokinetic profile prediction was performed using in silico methods. Based on the results obtained in the study, it can be concluded that indole-functionalized triterpene EB367 is a promising starting point for further research in the field of breast cancer therapy or the synthesis of new derivatives. [ABSTRACT FROM AUTHOR]

Minocycline is a drug which induces skin hyperpigmentation. Its frequency reaches up to 50% of treated patients. The adverse effect diminishes the great therapeutic potential of minocycline, including antibacterial, neuroprotective, anti-inflammatory and anti-cancer actions. It is supposed that an elevated melanin level and drug accumulation in melanin-containing cells are related to skin hyperpigmentation. This study aimed to evaluate molecular and biochemical mechanism of minocycline-induced hyperpigmentation in human normal melanocytes, as well as the contribution of UV radiation to this side effect. The experiments involved the evaluation of cyto- and phototoxic potential of the drug using cell imaging with light and confocal microscopes as well as biochemical and molecular analysis of melanogenesis. We showed that minocycline induced melanin synthesis in epidermal melanocytes. The action was intensified by UV irradiation, especially with the UVB spectrum. Minocycline stimulated the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase (TYR) gene. Higher levels of melanin and increased activity of tyrosinase were also observed in treated cells. Moreover, minocycline triggered the supranuclear accumulation of tyrosinase, similar to UV radiation. The decreased level of premelanosome protein PMEL17 observed in all minocycline-treated cultures suggests disorder of the formation, maturation or distribution of melanosomes. The study revealed that minocycline itself was able to enhance melanin synthesis. The action was intensified by irradiation, especially with the UVB spectrum. Demonstrated results confirmed the potential role of melanin and UV radiation minocycline-induced skin hyperpigmentation. [ABSTRACT FROM AUTHOR]

Minocycline is a semisynthetic tetracycline antibiotic. In addition to its antibacterial activity, minocycline shows many non-antibiotic, beneficial effects, including antioxidative action. The property is responsible, e.g., for anti-inflammatory, neuroprotective, and cardioprotective effects of the drug. However, long-term pharmacotherapy with minocycline may lead to hyperpigmentation of the skin. The reasons for the pigmentation disorders include the deposition of the drug and its metabolites in melanin-containing cells and the stimulation of melanogenesis. The adverse drug reaction raises a question about the influence of the drug on melanocyte homeostasis. The study aimed to assess the effect of minocycline on redox balance in human normal melanocytes HEMn-LP exposed to hydrogen peroxide and UVA radiation. The obtained results indicate that minocycline induced oxidative stress in epidermal human melanocytes. The drug inhibited cell proliferation, decreased the level of reduced thiols, and stimulated the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). The described changes were accompanied by an increase in the intracellular level of ROS. On the other hand, pretreatment with minocycline at the same concentrations increased cell viability and significantly attenuated the oxidative stress in melanocytes exposed to hydrogen peroxide and UVA radiation. Moreover, the molecular docking analysis revealed that the different influence of minocycline and other tetracyclines on CAT activity can be related to the location of the binding site. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Simple Summary: The most important biological function of vitamin B12 (cobalamin) is to accomplish DNA synthesis, which is necessary for cell division. Cobalamin deficiency may be especially acute for rapidly dividing cells, such as glioblastoma cells. Therefore, cobalamin antagonists offer a medicinal potential for developing anti-glioma agents. In the present study, we revealed, for the first time, that the induction of cobalamin deficiency by vitamin B12 antagonist with affinity to key transporter of cobalamins, inhibited glioblastoma cells growth and promoted cell cycle arrest. The effect was observed for non-toxic concentration of the agent, as demonstrated on zebrafish. Moreover, as compared to our previous study, the cytostatic effect of the agent was more pronounced in glioblastoma cells than in normal astrocytes. We believe that the study may become the basis for further in vitro and in vivo experiments concerning cobalamin deprivation as a potential therapeutic strategy for glioblastoma. The most important biological function of vitamin B12 is to accomplish DNA synthesis, which is necessary for cell division. Cobalamin deficiency may be especially acute for rapidly dividing cells, such as glioblastoma cells. Therefore, cobalamin antagonists offer a medicinal potential for developing anti-glioma agents. In the present study, we developed an in vitro model of cobalamin deficiency in glioblastoma cells. Long-term treatment of cells with the cobalamin analogue, hydroxycobalamin [c-lactam] (HCCL) was applied to induce an increase of hypocobalaminemia biomarker. Cytometric assays demonstrated that vitamin B12 promoted glioblastoma cells proliferation, whereas the treatment of cells with HCCL caused a dramatic inhibition of cell proliferation and an induction of cell cycle arrest at the G2/M phase. Vitamin B12 counteracted all the observed effects of HCCL. In the in silico study, we characterized the molecular interactions between HCCL and transcobalamin II (TCII). We have demonstrated that HCCL shares similar interactions with TCII as naturally occurring cobalamins and therefore may act as a competitive inhibitor of this key transporter protein. We assessed the impact of HCCL on the mortality or developmental malformations of zebrafish embryos. Collectively, our findings suggest that the use of cobalamin transport antagonists as potential anti-glioma agents would be worth exploring further. [ABSTRACT FROM AUTHOR]

Cobalamin deficiency affects human physiology with sequelae ranging from mild fatigue to severe neuropsychiatric abnormalities. The cellular and molecular aspects of the nervous system disorders associated with hypovitaminosis B12 remain largely unknown. Growing evidence indicates that astrogliosis is an underlying component of a wide range of neuropathologies. Previously, we developed an in vitro model of cobalamin deficiency in normal human astrocytes (NHA) by culturing the cells with c-lactam of hydroxycobalamin (c-lactam OH-Cbl). We revealed a non-apoptotic activation of caspases (3/7, 8, 9) in cobalamin-deficient NHA, which may suggest astrogliosis. The aim of the current study was to experimentally verify this hypothesis. We indicated an increase in the cellular expression of two astrogliosis markers: glial fibrillary acidic protein and vimentin in cobalamin-deficient NHA using Western blot analysis and immunocytochemistry with confocal laser scanning microscopy. In the next step of the study, we revealed c-lactam OH-Cbl as a potential non-toxic vitamin B12 antagonist in an in vivo model using zebrafish embryos. We believe that the presented results will contribute to a better understanding of the cellular mechanism underlying neurologic pathology due to cobalamin deficiency and will serve as a foundation for further studies. [ABSTRACT FROM AUTHOR]

Minocycline is a tetracycline compound with pleiotropic pharmacological properties. In addition to its antibacterial action, it shows many non-antimicrobial effects, including an anti-cancer activity. The anti-cancer action was confirmed in studies on ovarian carcinoma cells, hepatocellular carcinoma cells, glioma cells, or acute myeloid leukemia cells. Malignant melanoma remains a serious medical problem despite the extensive knowledge of the disease. The low effectiveness of the standard treatment, as well as the resistance to therapy, result in high mortality rates. This work aimed to investigate the potential and mechanisms of anti-melanoma action of minocycline. Human skin melanotic melanoma cell line COLO 829 was used in the study. The obtained results showed that minocycline decreased cell viability and inhibited the growth of melanoma cells, proportional to the drug concentration as well as to the time of incubation. The EC50 values were calculated to be 78.6 µM, 31.7 µM, and 13.9 µM for 24 h, 48 h, and 72 h, respectively. It was observed that treated cells had a disturbed cell cycle and significantly changed morphology. Moreover, minocycline caused a decrease in mitochondrial membrane potential and an increase in cells with a low level of reduced thiols. Finally, it was found that the anti-melanoma effect of minocycline was related to the induction of apoptosis. The drug activated caspases 8, 9, and 3/7 as well as increased the number of annexin V-positive cells. The presented results show that minocycline possesses anti-melanoma potential. [ABSTRACT FROM AUTHOR]

Cobalamin deficiency is an important health problem. The major non-hematological symptoms of hypocobalaminemia are nervous system disorders, but the molecular and cellular mechanisms underlying this phenomenon have not yet been fully explained. Increasing scientific evidence is stressing the pivotal role of astrocyte dysfunction in the pathogenesis of a wide range of neurological disorders. In light of the above, the aim of this study was to develop an in vitro model of cobalamin deficiency by optimizing the conditions of astrocyte culture in the presence of vitamin B12 antagonist, and then the model was used for multidirectional analysis of astrocyte homeostasis using image cytometry, immunoenzymatic and colorimetric assays, and fluorescence spectroscopy. Our results indicated that long-term incubation of normal human astrocytes with hydroxycobalamin(c-lactam) causes an increase of extracellular homocysteine level, a reduction of cell proliferation, and an accumulation of cells in the G2/M cell cycle phase. Moreover, we observed dramatic activation of caspases and an increase of catalase activity. Interestingly, we excluded extensive apoptosis and oxidative stress. The study provided significant evidence for astrocyte homeostasis disturbance under hypocobalaminemia, thus indicating an important element of the molecular mechanism of nervous system diseases related to vitamin B12 deficiency. [ABSTRACT FROM AUTHOR]

Vitamin B12 deficiency causes significant changes in cellular metabolism leading to various clinical symptoms, such as hematological, psychiatric, and neurological disorders. We hypothesize that skin pigmentation disorders may be a diagnostically important manifestation of vitamin B12 deficiency, however the cellular and molecular mechanisms underlying these effects remain unknown. The aim of this study was to examine the effect of vitamin B12 deficiency on melanocytes homeostasis. Hypocobalaminemia in vitro model was developed by treating epidermal melanocytes with synthesized vitamin B12 antagonist—hydroxycobalamin(c-lactam). The cells were examined using immunoenzymatic, spectrophotometric, and fluorimetric assays as well as image cytometry. Significant melanogenesis stimulation—the increase of relative melanin content and tyrosinase activity up to 131% and 135%, respectively—has been indicated. Cobalamin-deficient cells displayed the elevation (by 120%) in reactive oxygen species level. Moreover, the redox status imbalance was stated. The study provided a scientific evidence for melanocytes homeostasis disturbance under hypocobalaminemia, thus indicating a significant element of the hyperpigmentation mechanism due to vitamin B12 deficiency. Furthermore, the implication between pigmentary and hematological and/or neuropsychiatric symptoms in cobalamin-deficient patients may be an important issue. [ABSTRACT FROM AUTHOR]

Malignant melanoma is a high aggressive malignancy in humans and causes 60–80% of deaths from skin cancer. Defect in an intrinsic pathway of apoptosis via overexpression of Mcl‐1 is responsible for malignant melanoma development and progression, and also for resistance to chemotherapeutic agents. MIM1 is a specific low molecular Mcl‐1 protein inhibitor that is able to induce Mcl‐1‐dependent cancer cells death. Here, we examined the effect of MIM1 as well as MIM1 and dacarbazine (DTIC) mixture on cell viability, apoptosis, and cell cycle progression in COLO829 melanoma cells. Cell viability was performed by the WST‐1 assay. Analysis of apoptosis as well as cell cycle progression was determined by fluorescence image cytometer NucleoCounter NC‐3000. The obtained results demonstrated that the MIM1 exhibited high cytotoxicity against melanotic melanoma cells and induced mitochondrial membrane breakdown, GSH depletion, and DNA fragmentation. Additionally, MIM1 enhanced the proapoptotic effect of DTIC toward melanoma cells; furthermore, a mixture of these drugs caused cell cycle arrest at G2/M phase in COLO829 cells. Taken together, these data provide, for the first time, evidence that a low molecular weight Mcl‐1 inhibitor—MIM1 may be a promising agent with antitumor and proapoptotic properties toward melanoma cells. [ABSTRACT FROM AUTHOR]

Flavonoids exert many beneficial properties, such as anticancer activity. They were found to have chemopreventive effects hindering carcinogenesis, and also being able to affect processes important for cancer cell pathophysiology inhibiting its growth or promoting cell death. There are also reports on the chemosensitizing properties of flavonoids, which indicate that they could be used as a support of anticancer therapy. It gives promise for a novel therapeutic approach in tumors characterized by ineffective treatment, such as high-grade gliomas. The research was conducted on the in vitro culture of human SW1783 anaplastic astrocytoma cells incubated with neobavaisoflavone (NEO), doxorubicin, etoposide, and their combinations with NEO. The analyses involved the WST-1 cell viability assay and image cytometry techniques including cell count assay, Annexin V assay, the evaluation of mitochondrial membrane potential, and the cell-cycle phase distribution. We found that NEO affects the activity of doxorubicin and etoposide by reducing the viability of SW1783 cells. The combination of NEO and etoposide caused an increase in the apoptotic and low mitochondrial membrane potential subpopulations of SW1783 cells. Changes in the cell cycle were observed in all combined treatments. These findings indicate a potential chemosensitizing effect exerted by NEO. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Glioblastoma (GB) is the most common type of glioma, which is distinguished by high mortality. Due to the rapid progression of the tumor and drug resistance, the treatment is often ineffective. The development of novel therapies in a big part concerns the application of anti-cancer agents already used in clinical practice, unfortunately often with limited effects. This could be overcome through the use of compounds that possess chemosensitizing properties. In our previous work, it has been shown that neobavaisoflavone (NBIF) enhances the in vitro activity of doxorubicin in GB cells. The aim of this study was a further investigation of the possible chemosensitizing effects of this isoflavone. The experimental panel involving image cytometry techniques, such as count assay, examination of mitochondrial membrane potential, Annexin V assay, and cell cycle analysis, was performed in human glioblastoma U-87 MG cells and normal human astrocytes (NHA) treated with NBIF, doxorubicin, etoposide, and their mixes with NBIF. NBIF in co-treatment with etoposide or doxorubicin caused an increase in the population of apoptotic cells and prompted alterations in the cell cycle. NBIF enhances the pro-apoptotic activity of etoposide and doxorubicin in U-87 MG cells, which could be a sign of the chemosensitizing properties of the isoflavone. [ABSTRACT FROM AUTHOR]

Malignant melanoma is responsible for the majority of skin cancer-related deaths. The methods of cancer treatment include surgical removal, chemotherapy, immunotherapy, and targeted therapy. However, neither of these methods gives satisfactory results. Therefore, the development of new anticancer therapeutic strategies is very important and may extend the life span of people suffering from melanoma. The aim of this study was to examine the effect of ketoprofen (KTP) and UVA radiation (UVAR) therapy on cell proliferation, apoptosis, and cell cycle distribution in both melanotic melanoma cells (COLO829) and human melanocytes (HEMn-DP) in relation to its supportive effect in the treatment of melanoma. The therapy combining the use of pre-incubation with KTP and UVAR causes a significant increase in the anti-proliferative properties of ketoprofen towards melanoma cells and the co-exposure of melanotic melanoma cells induced apoptosis shown as the mitochondrial membrane breakdown, cell-cycle deregulation, and DNA fragmentation. Moreover, co-treatment led to GSH depletion showing its pro-apoptotic effect dependent on ROS overproduction. The treatment did not show a significant effect on normal cells—melanocytes—which indicates its high selectivity. The results suggest a possible benefit from the use of the ketoprofen and ultraviolet A irradiation as a new concept of melanotic melanoma therapy. [ABSTRACT FROM AUTHOR]

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. • Phototoxicity of MLX disrupts redox homeostasis in melanocytes and fibroblasts. • MLX induces oxidative stress in fibroblasts and melanocytes exposed to UVAR. • MLX reduces SOD, CAT, and GPx in fibroblasts irradiated with UVA radiation. • MLX increases SOD, CAT, and GPx in melanocytes exposed to UVA radiation. • The presence of melanin may influence the response to meloxicam phototoxicity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Malignant melanoma is the cause of 80% of deaths in skin cancer patients. Treatment of melanoma in the 4th stage of clinical advancement, in which inoperable metastasis occur, does not provide sufficient effects. Ketoprofen has phototoxic properties and it can be used as a new treatment option for skin cancers as a part of photochemotherapy. The present study was designed to investigate whether ketoprofen in combination with UVA induces cytotoxic, anti-proliferative and pro-apoptotic effects on melanoma cells. It was stated that co-treatment with 1.0 mM ketoprofen and UVA irradiation disturbed homeostasis of C32 melanoma cells by lowering its vitality (decrease of GSH level). Contrary to C32 cells, melanocytes showed low sensitivity to ketoprofen and UVA radiation, pointing selectivity in the mode of action towards melanoma cells. Co-treatment with ketoprofen and UVA irradiation has cytotoxic and anti-proliferative and pro-apoptotic effect on C32. The co-treatment triggered the DNA fragmentation and changed the cell cycle in C32 cells. In conclusion, it could be stated that local application of ketoprofen in combination with UVA irradiation may be used to support the treatment of melanoma and creates the possibility of reducing the risk of cancer recurrence and metastasis. • Co-therapy with ketoprofen and UVA decreased vitality of C32 cells without effect on melanocytes. • Ketoprofen in combination with UVA exerted cytotoxic and anti-proliferative effect towards amelanotic melanoma cells. • Combined therapy with ketoprofen and UVA radiation exerted pro-apoptotic effect towards melanoma cells. • Co-treatment (ketoprofen and UVA) triggered the DNA fragmentation and changed the cell cycle in melanoma cells. [ABSTRACT FROM AUTHOR]

Mcl-1 is a potent antiapoptotic protein which is amplified in many human cancer, while microphthalmia associated transcription factor (MITF) promotes cell proliferation and has pro-survival role. The study was designed to examine whether the interaction between ciprofloxacin, one of the fluoroquinolones derivative, and MITF/Mcl-1 proteins affects C32 melanoma cells viability, proliferation and induces apoptosis. Preliminary molecular docking studies, Western blot analysis and fluorescence image cytometry were applied to demonstrate the signaling pathway underlying antiproliferative and proapoptotic effect of the drug. In silico analysis showed that ciprofloxacin possess the ability to form complexes with MITF and Mcl-1proteins. This phenomenon was confirmed by in vitro experimental model where the drug was found to decrease MITF and increase Mcl-1 expression at the protein level. Moreover, we found that ciprofloxacin decreases the cell viability and exerts anti-proliferative effect on amelanotic C32 melanoma cells. Image cytometric studies showed that the tested drug induced GSH depletion and apoptosis via intrinsic death pathway leading to DNA fragmentation. Analysis of the cell cycle distribution revealed that ciprofloxacin caused a block in the G 2 /M phase. This is the first study that characterized the role of MITF and Mcl-1 proteins in the antiproliferative and pro-apoptotic effect of ciprofloxacin towards amelanotic melanoma cells, opening the possibility to use of this drug as a potential agent for the treatment of melanoma. Unlabelled Image • Ciprofloxacin exerted in silico capacity for binding to MITF and Mcl-1 protein. • Ciprofloxacin suppressed MITF protein level in C32 melanoma cells. • The drug increased Mcl-1 protein level in amelanotic melanoma cells. • Ciprofloxacin decreased C32 cells viability and proliferation. • The drug induced apoptosis in amelanotic melanoma cells. [ABSTRACT FROM AUTHOR]

Doxycycline is a semisynthetic, second generation tetracycline. Currently, it is used, among others, in the treatment of acne and skin infections. Moreover, doxycycline has many valuable nonantibiotic properties, including anti-inflammatory, immunosuppressive and anticancer effects. Recent studies showed that the drug had the ability to inhibit the adhesion and migration of cancer cells, as well as affected their growth and proliferation and induced apoptosis. The purpose of this study was to examine the antimelanoma effect of doxycycline. The obtained results demonstrated that doxycycline decreased the viability and inhibited the proliferation of human melanoma cells, proportionally to the drug concentration and the treatment time. It was stated that doxycycline disturbed the homeostasis of the cells by lowering intracellular level of reduced thiols. In addition, the treatment changed the cell cycle profile and triggered the DNA fragmentation. Mitochondria of melanoma cells exposed to the drug had lowered membrane potential, which indicated cells apoptosis. Finally, doxycycline induced the externalization phosphatidylserine – a well-known hallmark of apoptosis, confirmed by results of annexin V test. The presented study contributes to the increase of knowledge about nonantibacterial action of doxycycline, including the influence on human cancer cells and indicates new potential possibility of effective treatment of malignant melanoma. Unlabelled Image • Doxycycline decreases the viability of human melanoma cells. • Doxycycline inhibits the proliferation of human melanoma cells. • Doxycycline decreases the intracellular level of reduced thiols. • Doxycycline triggers the DNA fragmentation in human melanoma cells. • Doxycycline reduces mitochondrial membrane potential in human melanoma cells. [ABSTRACT FROM AUTHOR]

Abstract Glioblastoma multiforme (GBM) is the most common and high aggressive malignant brain tumor. Despite evolving oncology treatment and novel chemotherapeutic agents the median survival of patients diagnosed with GBM is only 12–15 months. This grim fact highlights necessity to identify new drugs that could improve the effectiveness of GBM patients treatment. MIM1 is a specific low molecular Mcl-1 protein inhibitor able to induce Mcl-1-dependent cancer cells death. The aim of this study was to examine the effect of MIM1 as well as MIM1 and temozolomide (TMZ) mixture on cell viability, apoptosis and cell cycle progression in human U87MG glioblastoma cells. Cell viability was performed by the WST-1 assay. Mitochondrial membrane potential, Annexin V assay, DNA fragmentation and cell cycle distribution were determined by fluorescence image cytometer NucleoCounter NC-3000. The obtained results show that MIM1 and MIM1/TMZ mixture decrease glioblastoma cells viability in a dose- and time- dependent manner. Moreover, the exposure of U87MG cells to MIM1 and MIM1/TMZ mixture causes mitochondrial dysfunction as well as DNA fragmentation and cell cycle arrest at G 2 /M phase. This study provides for the first time convincing evidence that BH3 mimetic MIM1, which inhibits Mcl-1 antiapoptotic protein may be an efficacious molecule able to induction of apoptosis and sensitize GBM cells to alkylating agents. Highlights • MIM1 and mixture of MIM1 and temozolomide caused loss in human glioblastoma cells viability. • MIM1 and mixture of MIM1 and temozolomide induced apoptosis in human glioblastoma cells. • MIM1 and mixture of MIM1 and temozolomide caused changes in cell cycle progression. • MIM1 molecule induced apoptosis and sensitize glioblastoma cells to alkylating agents. [ABSTRACT FROM AUTHOR]

Although some fluoroquinolones have been found to exert anti-tumor activity, studies on the effect of these drugs on melanoma cells are relatively rare. The aim of this study was to examine the effect of lomefloxacin on cell viability, reactive oxygen species production, redox balance, cell cycle distribution, DNA fragmentation, and apoptosis in COLO829 melanoma cells. Lomefloxacin decreases the cell viability in a dose- and time-dependent manner. For COLO829 cells treated with the drug for 24, 48, and 72 h, the values of IC50 were found to be 0.51, 0.33, and 0.25 mmol/L, respectively. The analyzed drug also altered the redox signaling pathways, as shown by intracellular reactive oxygen species overproduction and endogeneous glutathione depletion. After lomefloxacin treatment, the cells were arrested in S- and G2/M-phase, suggesting a mechanism related to topoisomerase II inhibition. DNA fragmentation was observed when the cells were exposed to increasing lomefloxacin concentrations and a prolongation of incubation time. Moreover, it was demonstrated that the drug induced mitochondrial membrane breakdown as an early hallmark of apoptosis. The obtained results provide a strong molecular basis for the pharmacologic effect underlying the potential use of lomefloxacin as a valuable agent for the treatment of melanoma in vivo. [ABSTRACT FROM AUTHOR]

Purpose:Melanoma is an aggressive form of skin cancer. The aim of the study was to evaluate the influence of UVA radiation and psoralens: 5-methoxypsoralen (5-MOP) or 8-methoxypsoralen (8-MOP) on melanoma cells viability. Materials and methods:The amelanotic C32 and melanotic COLO829 human melanoma cell lines were exposed to increasing concentrations of psoralens (0.1–100μM) in the presence or absence of UVA radiation. Cell viability was evaluated by the WST-1 assay. Results:We demonstrated that 8-MOP, in contrast to 5-MOP, has no cytotoxic effect on both melanoma cell lines. Simultaneous exposure of cells to 8-MOP and UVA radiation caused significant cytotoxic response in C32 cells where the EC50value was estimated to be 131.0μM (UVA dose: 1.3 J/cm2) and 105.3μM (UVA dose: 2.6 J/cm2). The cytotoxicity of 5-MOP on both C32 and COLO829 cells was significantly augmented by UVA radiation – the EC50was estimated to be 22.7 or 7.9μM (UVA dose: 1.3 J/cm2) and 24.2 or 7.0μM (UVA dose: 2.6 J/cm2), respectively. Conclusions:The demonstrated high cytotoxic response after simultaneous exposure of melanoma cells to psoralens and UVA radiation in vitro suggests the usefulness of PUVA therapy to treat melanoma in vivo. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Transition metal coordination compounds play an important role in the treatment of neoplastic diseases. However, due to their low selectivity and bioavailability, as well as the frequently occurring phenomenon of drug resistance, new chemical compounds that could overcome these phenomena are still being sought. The solution seems to be the synthesis of new metal complexes conjugated with drug carriers, e.g., dendrimers. Numerous literature data have shown that dendrimers improve the bioavailability of the obtained metal complexes, solving the problem of their poor solubility and stability in an aqueous environment and also breaking down inborn and acquired drug resistance. Therefore, the aim of this study was to synthesize a novel imidazole platinum(II) complex conjugated with and without the second-generation PAMAM dendrimer (PtMet2–PAMAM and PtMet2, respectively) and to evaluate its antitumor activity. Cell viability studies indicated that PtMet2–PAMAM exhibited higher cytotoxic activity than PtMet2 in MCF-7 and MDA-MB-231 breast cancer cells at relatively low concentrations. Moreover, our results indicated that PtMet2–PAMAM exerted antiproliferative effects in a zebrafish embryo model. Treatment with PtMet2–PAMAM substantially increased apoptosis in a dose-dependent manner via caspase-9 (intrinsic pathway) and caspase-8 (extrinsic pathway) activation along with pro-apoptotic protein expression modulation. Additionally, we showed that apoptosis can be induced by activating POX, which induces ROS production. Furthermore, our results also clearly showed that the tested compounds trigger autophagy through p38 pathway activation and increase Beclin-1, LC3, AMPK, and mTOR inhibition. The high pro-apoptotic activity and the ability to activate autophagy by the imidazole platinum(II) complex conjugated with a dendrimer may be due to its demonstrated ability to reverse multidrug resistance (MDR) and thereby increase cellular accumulation in breast cancer cells. [ABSTRACT FROM AUTHOR]

Phototoxicity of fluoroquinolones is connected with oxidative stress induction. Lomefloxacin (8-halogenated derivative) is considered the most phototoxic fluoroquinolone and moxifloxacin (8-methoxy derivative) the least. Melanin pigment may protect cells from oxidative damage. On the other hand, fluoroquinolone–melanin binding may lead to accumulation of drugs and increase their toxicity to skin. The study aimed to examine the antioxidant defense system status in normal melanocytes treated with lomefloxacin and moxifloxacin and exposed to UV-A radiation. The obtained results demonstrated that UV-A radiation enhanced only the lomefloxacin-induced cytotoxic effect in tested cells. It was found that fluoroquinolones alone and with UV-A radiation decreased superoxide dismutase (SOD) activity and SOD1 expression. UV-A radiation enhanced the impact of moxifloxacin on hydrogen peroxide-scavenging enzymes. In turn, lomefloxacin alone increased the activity and the expression of catalase (CAT) and glutathione peroxidase (GPx), whereas UV-A radiation significantly modified the effects of drugs on these enzymes. Taken together, both analyzed fluoroquinolones induced oxidative stress in melanocytes, however, the molecular and biochemical studies indicated the miscellaneous mechanisms for the tested drugs. The variability in phototoxic potential between lomefloxacin and moxifloxacin may result from different effects on the antioxidant enzymes. [ABSTRACT FROM AUTHOR]