Pterostilbene-Mediated Inhibition of Cell Proliferation and Cell Death Induction in Amelanotic and Melanotic Melanoma.

Melanoma is one of the fastest-growing cancers worldwide. Treatment of advanced melanoma is very difficult; therefore, there is growing interest in the identification of new therapeutic agents. Pterostilbene is a natural stilbene that has been found to have several pharmacological activities. The aim of this study was to evaluate the influence of pterostilbene on the proliferation and apoptosis of human melanoma cells. Proliferation of pterostilbene-treated amelanotic (C32) and melanotic (A2058) melanoma cells was determined by BRDU assay. Flow cytometric analyses were used to determine cell cycle progression, and further molecular investigations were performed using real-time RT-qPCR. The expression of the p21 protein and the DNA fragmentation assay were determined by the ELISA method. The results revealed that pterostilbene reduced the proliferation of both amelanotic and melanotic melanoma cells. Pterostilbene induced apoptosis in amelanotic C32 melanoma cells, and this effect was mediated by an increase in the expression of the BAX, CASP9, and CASP9 genes; induction of caspase 3 activity; and DNA degradation. Pterostilbene did not affect the activation of apoptosis in the A2058 cell line. It may be concluded that pterostilbene has anticancer potential against human melanoma cells; however, more studies are still needed to fully elucidate the effects of pterostilbene on amelanotic and melanotic melanoma cells.

The role of UVA radiation in ketoprofen-mediated BRAF-mutant amelanotic melanoma cells death - A study at the cellular and molecular level.

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.

Primary photodynamic therapy for small amelanotic choroidal melanomas: consecutive case series of 69 patients with at least 24-month follow-up.

AIMS: To investigate the success and recurrence rates and visual outcomes in a large case series of amelanotic posterior choroidal melanomas treated by means of primary photodynamic therapy (PDT) with verteporfin. METHODS: Retrospective case series from a single specialist ocular oncology centre. All patients had a clinical diagnosis of choroidal melanoma and were selected for PDT based on tumour characteristics. Included patients had at least 24 months of follow-up from initiation of treatment and all but one had not received treatment prior to PDT. RESULTS: 69 patients were included. Mean tumour thickness was 1.9 mm (range 0.5-4.4), while the mean basal diameter was 6.9 mm (range 2.4-11.0). Included lesions were stage cT1a (n=66) or cT2a (n=3). The mean duration of follow-up from treatment initiation was 57 months (range 24-116 months). Seven lesions (10%) failed to respond to PDT. 10 patients (16%) experienced recurrence during follow-up. Overall success rate in this series was 75% (n=52). 83% of successfully treated patients (n=43) maintained or gained vision by final follow-up. Visual outcomes were significantly better in those patients who received PDT therapy alone in comparison to those who needed other treatments for their melanoma (Fisher's exact test, p=0.004). Unfortunately, one patient (1.4%) in the series developed systemic metastases and died. CONCLUSION: Selected amelanotic posterior uveal melanomas may be successfully treated with PDT with retention of good vision in the majority of cases, maintained with a mean of 57 months (minimum of 24 months) of follow-up.

Multimodal Imaging of Nodular Posterior Scleritis: Case Report and Review of the Literature.

Nodular posterior scleritis represents a small percentage of all cases of posterior scleritis. Because of the scarcity of nodular posterior scleritis, it may be confused or even misdiagnosed as an intraocular tumor or posterior uveitis. Here, we are reporting a case of nodular posterior scleritis in a 25-year-old medically free male. Furthermore, we reviewed previously reported cases of nodular posterior scleritis. Our patient presented with a choroidal mass of about one disc diameter in size. In addition, the patient had exudative retinal detachment and chorioretinal folds. B scan ultrasonography showed subretinal fluid, macular nodular thickening and underlying echolucent area along with medium internal reflectivity on A scan. Fluorescein angiography revealed early pinpoint areas of hyperfluorescence and late pooling under the detached retina. Indocyanine green angiography demonstrated early diffuse hypofluorescence corresponding to the area of detachment and late multiple pinpoint spots of hyperfluorescence. After intravenous methylprednisolone 1 g for 3 days followed by a course of oral prednisolone along with mycophenolate mofetil, the patient experienced rapid recovery with improvement in vision and complete resolution of subretinal fluid. On further follow-up, the patient regained 20/20 vision. Nodular posterior scleritis is a rare unilateral disease with strong female predominance. Multimodal imaging should be employed to confirm the diagnosis. The disease must be diagnosed correctly to avoid any unnecessary diagnostic work-up and aggressive management. Most cases carry excellent prognosis with no recurrence.

[A Case of Primary Amelanotic Malignant Melanoma of the Esophagus, Wherein Pseudoprogression Was Suspected during Immune Checkpoint Inhibitor Treatment].

A 78-year-old man was admitted to our hospital with a diagnosis of esophageal cancer and gastric cancer. Gastroscopy showed a type 2 tumor located in the cardia from the lower esophagus, and a pathological examination showed malignant melanoma. Based on the physical examination and other imaging tests, the patient was diagnosed with primary amelanotic malignant melanoma of the esophagus, but the tumor was unresectable due to extensive lymph node metastasis. According to the guideline, immune checkpoint inhibitor(nivolumab)was used for treatment, but because the tumor progressed after 2 courses and the performance status of the patient worsened, aggressive treatment was ended. Six weeks after finishing treatment, computed tomography showed that the tumor had shrunk to some extent. The patient ultimately died from aspiration pneumonia 4 months after the first consultation. The patient was thought to have had an immune-related adverse event, with the tumor showing pseudoprogression.

Cytotoxic Effect of Vanicosides A and B from Reynoutria sachalinensis Against Melanotic and Amelanotic Melanoma Cell Lines and in silico Evaluation for Inhibition of BRAFV600E and MEK1.

Vanicosides A and B are the esters of hydroxycinnamic acids with sucrose, occurring in a few plant species from the Polygonaceae family. So far, vanicosides A and B have not been evaluated for anticancer activity against human malignant melanoma. In this study, we tested these two natural products, isolated from Reynoutria sachalinensis rhizomes, against two human melanoma cell lines (amelanotic C32 cell line and melanotic A375 cell line, both bearing endogenous BRAFV600E mutation) and two normal human cell lines-keratinocytes (HaCaT) and the primary fibroblast line. Additionally, a molecular docking of vanicoside A and vanicoside B with selected targets involved in melanoma progression was performed. Cell viability was studied using an MTT assay. A RealTime-Glo™ Annexin V Apoptosis and Necrosis assay was used for monitoring programmed cell death (PCD). Vanicoside A demonstrated strong cytotoxicity against the amelanotic C32 cell line (viability of the C32 cell line was decreased to 55% after 72 h incubation with 5.0 µM of vanicoside A), significantly stronger than vanicoside B. This stronger cytotoxic activity can be attributed to an additional acetyl group in vanicoside A. No significant differences in the cytotoxicity of vanicosides were observed against the less sensitive A375 cell line. Moreover, vanicosides caused the death of melanoma cells at concentrations from 2.5 to 50 µM, without harming the primary fibroblast line. The keratinocyte cell line (HaCaT) was more sensitive to vanicosides than fibroblasts, showing a clear decrease in viability after incubation with 25 µM of vanicoside A as well as a significant phosphatidylserine (PS) exposure, but without a measurable cell death-associated fluorescence. Vanicosides induced an apoptotic death pathway in melanoma cell lines, but because of the initial loss of cell membrane integrity, an additional cell death mechanism might be involved like permeability transition pore (PTP)-mediated necrosis that needs to be explored in the future. Molecular docking indicated that both compounds bind to the active site of the BRAFV600E kinase and MEK-1 kinase; further experiments on their specific inhibitory activity of these targets should be considered.

The role of MITF and Mcl-1 proteins in the antiproliferative and proapoptotic effect of ciprofloxacin in amelanotic melanoma cells: In silico and in vitro study.

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 G2/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.

AUSTRALIAN AND NEW ZEALAND STUDY OF PHOTODYNAMIC THERAPY IN CHOROIDAL AMELANOTIC MELANOMA.

PURPOSE: To evaluate the safety and efficacy of primary photodynamic therapy (PDT) for posterior choroidal amelanotic melanomas. METHODS: Patients with posterior choroidal amelanotic melanomas up to 6 mm in height were treated with PDT using verteporfin as the photosensitizing agent. Treatment was repeated every 3 months until the tumor was flat up to a maximum of 6 treatments. Tumor response and recurrence was assessed by clinical examination, photography, and ultrasonography. Patients were monitored 3 monthly for a minimum of 3 years. RESULTS: Thirty-six of 41 (88%) patients had complete regression after an initial course of PDT. Of them, 20 (56%) had no recurrence, 3 (8%) had recurrences that were successfully treated with further PDT, and 13 (36%) had recurrences that failed or were not amenable to further PDT. None of the measured baseline characteristics predicted treatment outcomes. There was no reduction in visual acuity due to PDT. The mean follow-up time was 3.5 years. CONCLUSION: In this large series, primary PDT was highly effective in achieving initial regression of posterior choroidal amelanotic melanomas. Photodynamic therapy is a vision-preserving treatment option for these tumors; however, patients need to be followed up closely because there is a significant rate of recurrence.

Promotion of TRAIL/Apo2L-induced apoptosis by low-dose interferon-ß in human malignant melanoma cells.

Interferon ß (IFN-ß) is considered a signaling molecule with important therapeutic potential in cancer since IFN-ß-induced gene transcription mediates antiproliferation and cell death induction. Whereas, TNF-related apoptosis inducing ligand/Apo2 ligand (TRAIL/Apo2L) has emerged as a promising anticancer agent because it induces apoptosis specifically in cancer cells. In this study, we elucidated that IFN-ß augments TRAIL-induced apoptosis synergistically using five human malignant melanoma cells. All of these cells were induced apoptosis by TRAIL. Whereas, the response against IFN-ß was different in amelanotic cells (A375 and CRL1579) and melanotic cells (G361, SK-MEL-28, and MeWo). The responsibility of amelanotic cells against IFN-ß was higher than those of melanotic cells. The synergism of IFN-ß and TRAIL were correlated with the responsibilities of the cells against IFN-ß. The synergistic interaction was confirmed by a combination index based on the Chou-Talalay method. The upregulation of apoptosis in amelanotic cells was caused by very low doses of IFN-ß (over 0.1 IU/ml). Both of p53-mediated intrinsic pathway and Fas-related extrinsic pathway were activated by IFN-ß alone and combination with TRAIL. Further, TRAIL death receptors (DR4 and DR5) were upregulated by a low-dose IFN-ß (over 0.1 IU/ml) and the expression was more promoted by the combination with TRAIL. It was clarified that the upregulation of DR5 is associated with the declination of viability.

Context-dependent miR-204 and miR-211 affect the biological properties of amelanotic and melanotic melanoma cells.

Despite increasing amounts of experimental evidence depicting the involvement of non-coding RNAs in cancer, the study of BRAFV600E-regulated genes has thus far focused mainly on protein-coding ones. Here, we identify and study the microRNAs that BRAFV600E regulates through the ERK pathway.By performing small RNA sequencing on A375 melanoma cells and a vemurafenib-resistant clone that was taken as negative control, we discover miR-204 and miR-211 as the miRNAs most induced by vemurafenib. We also demonstrate that, although belonging to the same family, these two miRNAs have distinctive features. miR-204 is under the control of STAT3 and its expression is induced in amelanotic melanoma cells, where it acts as an effector of vemurafenib's anti-motility activity by targeting AP1S2. Conversely, miR-211, a known transcriptional target of MITF, is induced in melanotic melanoma cells, where it targets EDEM1 and consequently impairs the degradation of TYROSINASE (TYR) through the ER-associated degradation (ERAD) pathway. In doing so, miR-211 serves as an effector of vemurafenib's pro-pigmentation activity. We also show that such an increase in pigmentation in turn represents an adaptive response that needs to be overcome using appropriate inhibitors in order to increase the efficacy of vemurafenib.In summary, we unveil the distinct and context-dependent activities exerted by miR-204 family members in melanoma cells. Our work challenges the widely accepted "same miRNA family = same function" rule and provides a rationale for a novel treatment strategy for melanotic melanomas that is based on the combination of ERK pathway inhibitors with pigmentation inhibitors.

Proteasome inhibitors against amelanotic melanoma.

The incidence of malignant melanoma, the most aggressive skin cancer, is increasing constantly. Despite new targeted therapies, the prognosis for patients with metastatic disease remains poor. Thus, there is a need for new combinational treatments, and antineoplastic agents potentially valuable in this approach are inhibitors of the ubiquitin-proteasome system (UPS). In this work, we analyze the cytotoxicity mechanisms of proteasome inhibitors (MG-132, epoxomicin, and lactacystin) in a specific form of melanoma which does not synthesize melanin-the amelanotic melanoma (Ab cells). We found that the most cytotoxic of the compounds tested was epoxomicin. Caspase-9 activation as well as cytochrome C and AIF release from mitochondria indicated that exposure to epoxomicin induced the mitochondrial pathway of apoptosis. Epoxomicin treatment also resulted in accumulation of Bcl-2 family members-proapoptotic Noxa and antiapoptotic Mcl-1, which were postulated as the targets for bortezomib in melanoma. Inhibition of caspases by BAF revealed that cell death was partially caspase-independent. We observed no cell cycle arrest preceding the apoptosis of Ab cells, even though cdk inhibitors p21Cip1/Waf1 and p27Kip1 were up-regulated. The cell cycle was blocked only after inactivation of caspases by the pan-caspase inhibitor BAF. In summary, this is the first study exploring molecular mechanisms of cell death induced by epoxomicin in melanoma. We found that Ab cells died on the mitochondrial pathway of apoptosis and also partially by the caspase-independent way of death. Apoptosis induction was fast and efficient and was not preceded by cell cycle arrest.

Delivery of a hydrophobic phthalocyanine photosensitizer using PEGylated gold nanoparticle conjugates for the in vivo photodynamic therapy of amelanotic melanoma.

Photodynamic therapy (PDT) is a treatment of cancer whereby tumours are destroyed by reactive oxygen species generated upon photoactivation of a photosensitizer drug. Hydrophobic photosensitizers are known to be ideal for PDT; however, their hydrophobicity necessitates that they are typically administered using emulsions. Here, a delivery vehicle for photodynamic therapy based on the co-self-assembly of both a Zn(ii)-phthalocyanine derivative photosensitizer and a polyethylene glycol (PEG) derivative onto gold nanoparticles is reported. The PEG on the particle surface ensured that the conjugates were water soluble and enhanced their retention in the serum, improving the efficiency of PDT in vivo. The pharmacokinetic behaviour of the nanoparticle conjugates following intravenous injection into C57/BL6 mice bearing a subcutaneous transplanted B78H1 amelanotic melanoma showed a significant increase of retention of the nanoparticles in the tumour. PDT tumour destruction was achieved 3 h following injection of the nanoparticle conjugates leading to a remarkable 40% of the treated mice showing no tumour regrowth and complete survival. These results highlight that dual functionalised nanoparticles exhibit significant potential in PDT of cancer especially for difficult to treat cancers such as amelanotic melanoma.

BRACHYTHERAPY ALONE OR WITH NEOADJUVANT PHOTODYNAMIC THERAPY FOR AMELANOTIC CHOROIDAL MELANOMA: Functional Outcomes and Local Tumor Control.

PURPOSE: To compare visual outcomes and local tumor control between two groups of patients with amelanotic choroidal melanoma treated with brachytherapy alone, or neoadjuvant photodynamic therapy before brachytherapy. METHODS: Patients diagnosed with amelanotic choroidal melanoma were recruited for the study and divided into two groups: brachytherapy alone (Group A) and photodynamic therapy preceding brachytherapy (Group B). Patients of both groups were selected to be comparable. RESULTS: Twenty-six patients with amelanotic choroidal melanoma were enrolled in the study. Within Group B, 1 month after photodynamic therapy, ultrasonography showed reduction of tumor height in 11 patients (73.4%). The mean doses of irradiation to macula and optic nerve, at baseline were 74.37 and 52.07 Gy, whereas after photodynamic therapy there was a decrease of 17.26% (P = 0.008) and 21.22% (P = 0.025), respectively. In terms of visual acuity, a mean decrease of 14 ETDRS letters and 5 ETDRS letters was observed at 24 months follow-up, in Groups A and B, respectively (P = 0.001). CONCLUSION: Photodynamic therapy as neoadjuvant therapy before brachytherapy reduces tumor thickness in 73.4% of cases. As a result, a decrease of radiation toxic effects on visual function could be obtained, without compromising disease control.

MOLECULAR EFFECTS OF AMINE DERIVATIVES OF PHENOTHIAZINE ON CANCER CELLS C-32 AND SNB-19 IN VITRO.

Cancer therapy is challenging for scientists because of low effectiveness of so far existing therapies (especially in case of great invasiveness and advanced tumor stage). Such need for new drug development and search for more efficient new findings in therapeutical applications is therefore still valid. There are also conducted studies on modifying so far existing drugs and their new methods of usage in oncology practice. One of them is phenothiazine and its derivatives which are used in psychiatric treatment for years. They also exhibit antiprion, antiviral, antibacterial and antiprotozoal properties. Cytotoxic activity, influence on proliferation, ability to induce apoptosis suggest also a possibility of phenothiazine derivatives usage in cancer cells termination. The aim of our the study was to evaluate the influence of two amine derivatives of phenothiazine on cancer cells in vitro. Amelanotic melanoma C-32 cell line (ATCC) and glioma SNB-19 cells (DSMZ) were used in this study and two derivatives were analyzed. In view of examined substances tumor potential toxicity cells proliferation and viability exposed to phenothiazine derivatives were established. Cell cycle regulatory genes expression (TP53 and CDKN1A), S-phase marker--H3 gene and intracellular apoptosis pathway genes (BAX, BCL-2) were analyzed using RT-QPCR method. The influence of examined derivatives on total cell oxidative status (TOS), total antioxidative status (TAS), malondialdehyde concentration (MDA) and superoxide dismutase activity (SOD) were analyzed. As a result, examined phenothiazine derivatives cytotoxic action on C-32 and SNB-19 and also cells proliferation inhibition were determined. Cell cycle regulatory genes (TP53, CDKN1A) expression and protein products of genes involved in mitochondial apoptosis pathway (BAX, BCL-2) expression are changed by the presence of phenothiazine derivatives during culturing. There were also noted small changes in redox potential in cells exposed to two mentioned phenothiazine derivatives.

EFFECTS OF ZINGIBER OFFICINALE ROSCOE FRESH EXTRACT ON AMELANOTIC MELANOMA AND NORMAL SKIN FIBROBLASTS.

UNLABELLED: Zingiber officinale Roscoe is a very important medicinal plant, with a long history of therapeutic uses, especially in oriental traditional medicine. AIM: To investigate the cytotoxicity of a fresh ginger extract on some skin tumor cells compared to normal cells. MATERIAL AND METHODS: C32 amelanotic melanoma cell line and CCD human skin fibroblasts were used. The fresh extract obtained by crushing ginger rhizome was examined for phenolic content. The in vitro cytotoxicity was examined using phase contrast microscopy and MTT assay for the concentrations of 2 and 4 mg% total phenols. RESULTS: Both concentrations used for treatment induced no changes in normal the morphology and viability of fibroblasts compared to control cells. Amelanotic melanoma cells displayed profound changes in cell morphology such as cell shrinkage, rounding-up and membrane blebbing and a decrease in cell viability in a dose-dependent manner. CONCLUSIONS: Fresh ginger extract induced no changes in normal skin fibroblast viability, but caused profound cytotoxic effects on amelanotic melanoma. These results could encourage further studies regarding the intimate mechanisms of the antitumor action displayed by the fresh ginger extract.

Effects of electrophotodynamic therapy in vitro on human melanoma cells--melanotic (MeWo) and amelanotic (C32).

Photodynamic therapy has been considered ineffective for melanomas because of the competition between the absorbance of melanin from the melanoma and the absorbance of photosensitizers at the photosensitizer excitation light wavelength. Melanomas show considerable heterogeneity and resistance to phototherapy. The effectiveness of photodynamic therapy could be intensified by electroporation for enhanced transport of a photosensitizer by transient pores in the membrane. In this study, photodynamic therapy combined with electroporation was tested in vitro on the human melanoma cell lines melanotic melanoma (MeWo) and amelanotic melanoma (C32). Control experiments were conducted on human keratinocytes (HaCaT). Photofrin was used as a photosensitizer. Photosensitizer distribution, cloning efficacy test, comet assay, and assessment of apoptotic proteins were performed. Melanin levels were determined before and after photodynamic therapy. The experiments indicated that electroporation effectively supports the photodynamic method. It was found that photodynamic therapy with electroporation efficiently induces apoptosis in melanotic and amelanotic melanoma cells.

A case of giant nodular posterior scleritis mimicking choroidal malignancy.

To report a case of giant nodular posterior scleritis mimicking a choroidal tumor. A 42-year-old lady with systemic hypertension presented with a 1-week history of unilateral visual loss, pain and redness in her left eye. Examination showed sectoral anterior episcleritis in her left eye as well as a dome-shaped choroidal mass at the inferior-temporal periphery, associated with retinal hemorrhages and subretinal fluid. Systemic evaluation and imaging of the choroidal mass were performed and could not rule out amelanotic choroidal melanoma. At the same time, she was prescribed a 2-week course of oral nonsteroidal anti-inflammatory drug (NSAID) for her sectoral anterior episcleritis. The choroidal mass was found to have resolved completely right before her scheduled fine needle biopsy. Diagnosis of nodular posterior scleritis and a trial of oral NSAID can be considered in patients presenting with a choroidal mass before any invasive procedure.