Apoptosis In Melanoma Cells Research Articles

Patulin and LL-Z1640-2 induce apoptosis of cancer cells by decreasing endogenous protein levels of Zic family member 5.

Zic family member 5 (ZIC5) is a transcription factor that promotes the survival of several cancer cell types. As ZIC5 is expressed at minimal levels in normal human adult tissues, it is a potential therapeutic target. In this study, we screened a chemical library containing 3398 compounds that includes pre-existing drugs and compounds with known effects to identify ZIC5 inhibitors. In the first screening, 18 hit compounds decreased GFP intensity in melanoma A375 cells overexpressing GFP-tagged ZIC5. In the second screening, five compounds that attenuated ZIC5 protein levels in A375 cells were identified. Among them, LL-Z1640-2 and patulin selectively induced apoptosis in melanoma cells expressing ZIC5, while only inducing very low levels of apoptosis in normal human melanocytes, which have no detectable ZIC5 expression. LL-Z1640-2 and patulin also induced apoptosis in BRAF inhibitor-resistant melanoma, pancreatic cancer, cholangiocarcinoma and colorectal cancer cells. LL-Z1640-2- and patulin-mediated suppression of melanoma proliferation were rescued by ZIC5 overexpression. These results suggest that LL-Z1640-2 and patulin are promising compounds that decrease ZIC5 expression to induce apoptosis in cancer cells.

Circ_0084043-miR-134-5p axis regulates PCDH9 to suppress melanoma.

The low survival rates, poor responses, and drug resistance of patients with melanoma make it urgent to find new therapeutic targets. This study investigated whether the circ_0084043-miR-134-5p axis regulates the antitumor effect of protocadherin 9 (PCDH9) in melanoma. Ectopic expression or knock down (KD) of PCDH9 with a lentivirus vector, we explored its effects on the proliferation, invasion, and apoptosis of melanoma and verified its regulatory effect on ras-related C3 botulinum toxin substrate 1 (RAC1), proline-rich tyrosine kinase 2 (Pyk2), Cyclin D1, matrix metalloproteinase 2 (MMP2), and MMP9. We further observed the effect of KD circ_0084043 on the malignant behavior of melanoma and studied whether circ_0084043 sponged miR-134-5p and regulated PCDH9. We found that circ_0084043 was overexpressed in melanoma and associated with the malignant phenotype. PCDH9 was poorly expressed in human melanoma tissues, and overexpression of PCDH9 inhibited melanoma progression. Quantitative real-time PCR and Western blotting results showed that overexpression of PCDH9 could downregulate RAC1, MMP2, and MMP9 and upregulate Pyk2 and Cyclin D1. Circ_0084043 KD inhibited invasion and promoted apoptosis in melanoma cells. Circ_0084043 could sponge miR-134-5p and thus indirectly regulate PCDH9. Furthermore, we discovered that inhibiting circ_0084043 had an anti-PD-Ll effect. In vivo, PCDH9 overexpression inhibited melanoma tumor growth, but PCDH9 KD promoted it. In conclusion, PCDH9, which is regulated by the circ 0084043-miR-134-5p axis, can suppress malignant biological behavior in melanoma and influence the expression levels of Pyk2, RAC1, Cyclin D1, MMP2, and MMP9.

NCAPG2 contributes to the progression of malignant melanoma through regulating proliferation and metastasis.

Malignant melanoma is a highly aggressive cutaneous neoplasm with increasing incidence worldwide. Non-SMC condensin II complex subunit G2 (NCAPG2) exerts import biological function in the pathogenesis of several tumors. In this study, the functional roles of NCAPG2 knockdown in malignant melanoma were revealed in in vitro and in vivo experiments. In vitro study demonstrated that NCAPG2 depletion could inhibit proliferation and migration and promote apoptosis of malignant melanoma cells. Our in vivo date further confirmed that NCAPG2 knockdown attenuated tumor growth of malignant melanoma. Interestingly, NCAPG2 drove tumor development of malignant melanoma through activating the signal transducer and activator of transcription 3 (STAT3). In conclusion, this study elaborated the tumor-promoting effects of NCAPG2 on malignant melanoma, and NCAPG2 may be a potential therapeutic target for malignant melanoma therapy.

A tyrosinase-activated Pt(II) complex for melanoma photodynamic therapy and fluorescence imaging

Melanoma is a highly malignant skin cancer worldwide and it is more dangerous than other types of skin cancers because of its rapid and distant metastasis ability when not diagnosed and treated at an early stage. Tyrosinase, an enzyme that is a crucial biomarker of melanoma, is an important hotspot in research on melanoma. Herein a tyrosinase-activated cyclometalated Pt(II) complex (Pt-tyro) for melanoma photodynamic therapy (PDT) and fluorescence imaging was proposed for the first time, which was used in-vivo and in-vitro. Pt-tyro is under the specific activation via tyrosinase and rapidly rearranged and eliminated as fluorescent Pt-OH, which exhibits a higher phototoxicity and efficiently induces melanoma cell apoptosis. The prodrug Pt-tyro has the potential for use in displays imaging and photodynamic therapy in the A375 cell murine xenograft tumour model. Based on these findings, we suggest that the strategy combining imaging and treatment within a single fluorophore, may provide a reference for cancer theranostics.

Quality by design (QbD) assisted Fabrication & evaluation of Simvastatin loaded Nano-Enabled thermogel for melanoma therapy

Melanoma is a form of skin cancer that starts in melanocytes. Rampant chemo-resistance, metastasis, and inability to cross the skin barriers and accumulate within the tumor microenvironment render the conventional chemotherapeutic approaches ineffective. Simvastatin (SIM), a cholesterol synthesis inhibitor, has shown tremendous anticancer potential. Due to the lack of therapeutic alternatives, repositioning SIM in melanoma could be beneficial. Incorporating SIM within the nanoparticles promoted increased melanoma cell internalization, apoptosis, and sustained release profile. Further, the incorporation of nanoparticles into the thermogel facilitated depot formation over the upper dermal layers. Sol-to-gel transition at 34 °C was observed with a 14.03-fold increase in viscosity. This could be fruitful in limiting systemic exposure and preventing adverse effects. Entrapment of SIM in the PLGA NPs enhanced the cytotoxicity by 9.38-fold (p less than 0.05). Nuclear staining with DAPI showed blebbing, membrane shrinkage, and apoptosis confirmed by DCFDA and acridine orange/ethidium bromide staining. Ex vivo diffusion studies revealed the accumulation of C-6 loaded nanoparticles incorporated within the thermogel onto the upper dermal layer and depot formation up to 6 h. Thus, we conclude that SIM-loaded nanoparticulate thermogel could be an efficacious therapeutic alternative for melanoma.

Quality by design steered development of Niclosamide loaded liposomal thermogel for Melanoma: In vitro and Ex vivo evaluation

Melanoma is the most malignant form of skin cancer across the globe. Conventional therapies are currently ineffective which could be attributed to the rampant chemo-resistance, metastasis, inability to cross the skin barriers and accumulate within the tumor microenvironment. This advent brings in the principles of drug repurposing by repositioning Niclosamide (NIC), an anthelmintic drug for skin cancer. Incorporation into the liposomes facilitated enhanced melanoma cell uptake and apoptosis. Cytotoxicity studies revealed 1.756-fold enhancement in SK-MEL-28 cytotoxicity by NIC-loaded liposomes compared to free drug. Qualitative and quantitative cell internalization indicated greater drug uptake within the melanoma cells illustrating the efficacy of liposomes as efficient carrier systems. Nuclear staining showed blebbing and membrane shrinkage. Elevated ROS levels and apoptosis shown by DCFDA and acridine orange-ethidium bromide staining revealed greater melanoma cell death by liposomes compared to free drug. Incorporating NIC liposomes into the thermogel system restricted the liposomes as a depot onto the upper skin layers. Sustained zero order release up to 48 h with liposomes and 23.58-fold increase in viscosity led to the sol-to-gel transition at 33℃ was observed with liposomal thermogel. Ex vivo gel permeation studies revealed that C-6 loaded liposomes incorporated within the thermogel successfully formed a depot over the upper skin layer for 6 h to prevent transdermal delivery and systemic adverse effects. Thus, it could be concluded that NIC loaded liposomal thermogel system could be an efficacious therapeutic alternative for the management of melanoma.

Lithium Enhances Autophagy and Cell Death in Skin Melanoma: An Ultrastructural and Immunohistochemical Study.

Lithium is an inhibitor of glycogen synthase kinase 3 beta, which is traditionally used in the treatment of bipolar disorders and has antitumor effects. The aim of the current study was to determine if lithium salt causes autophagy and apoptosis in skin melanoma cells to enhance cell death. Light microscopy, transmission electron microscopy, immunohistochemistry, and immunofluorescence were used to study the mechanism of action of lithium carbonate in B16 melanoma cells in vivo. Proliferating cell nuclear antigen immunofluorescence assay revealed that the proliferation of B16 melanoma cells was suppressed by lithium treatment for 7 days. Electron microscopy demonstrated a significant increase in the number of autophagic vacuoles in lithium-treated cells relative to control. In addition, levels of autophagy markers LC3 beta and LAMP1 found in lithium-treated tumor xenografts were higher than levels of these markers in the control tumors. Lithium induced caspase-3 expression and apoptotic cell death in tumor cells. Thus, lithium carbonate is the compound that inhibits cell proliferation and stimulates cell death in melanoma cells through induction of autophagy and apoptosis. Stimulation of autophagy by lithium could contribute to the development of autophagic cell death in tumor cells.

Quercetin Mediated TET1 Expression Through MicroRNA-17 Induced Cell Apoptosis in Melanoma Cells.

A previous report suggested that the expression of ten-eleven translocation (TET) proteins is abnormal in certain cancers. Quercetin has been demonstrated as anti-cancer role in cancer development. In order to explore the inhibitory effect and mechanism of quercetin on uveal melanoma cells, the expression of TET proteins was analyzed in the present study. Our results suggest that the expression of TET1 was increased following treatment with quercetin in OCM-1, SK-MEL-1, and B16 cells. In addition, quercetin treatment induced apoptosis and inhibited migration and invasion. To further investigate the association of the expression of TET1 with cell growth, apoptosis, migration, and invasion, cell lines in which TET1 was knocked-down or overexpressed were constructed. The results showed that the increased expression of TET1-induced apoptosis, increased 5-hydroxymethylcytosine (5hmC). and inhibited invasion. Our bioinformatics studies indicated that TET1 is a target gene of microRNA-17 (miR-17) Our results showed that inhibition of the expression of miR-17 resulted in increased TET1 expression in OCM-1 cells. Furthermore, our results indicated that quercetin treatment increased TET1 expression and inhibited melanoma growth in nude mice. Taken together, our results suggest that quercetin can regulate cell proliferation and apoptosis through TET1 via miR-17 in melanoma cells.

NRF2-directed PRPS1 upregulation to promote the progression and metastasis of melanoma.

Phosphoribosyl pyrophosphate synthetase 1 (PRPS1) is the first enzyme in the de novo purine nucleotide synthesis pathway and is essential for cell development. However, the effect of PRPS1 on melanoma proliferation and metastasis remains unclear. This study aimed to investigate the regulatory mechanism of PRPS1 in the malignant progression of melanoma. Here, we found PRPS1 was upregulated in melanoma and melanoma cells. In addition, our data indicated that PRPS1 could promote the proliferation and migration and invasion of melanoma both in vitro and in vivo. PRPS1 also could inhibit melanoma cell apoptosis. Furthermore, we found NRF2 is an upstream transcription factor of PRPS1 that drive malignant progression of melanoma.

Retraction.

Retraction: 'Effects of miR-145-5p through NRAS on the cell proliferation, apoptosis, migration, and invasion in melanoma by inhibiting MAPK and PI3K/AKT pathways,' Sha Liu, Guozhen Gao, Dexiong Yan, Xiangjun Chen, Xingwei Yao, Shuzhong Guo, Guirong Li, Yu Zhao, Cancer Medicine. 2017; 819-833: The above article, published online on March 23, 2017 in Wiley Online Library (https://onlinelibrary.wiley.com/doi/10.1002/cam4.1030) has been retracted by agreement between the authors, the journal's Editor-in-Chief, Dr. Stephen Tait, and John Wiley & Sons Ltd. The retraction has been agreed following allegations raised by a third party. Multiple flaws and inconsistencies between the results presented and the experimental methods described were found, as well as instances of image manipulation across several figures. As a result, the editors consider the conclusions of this article to be invalid.

Cholecystokinin Receptor Antagonist Suppresses Melanoma Growth by Inducing Apoptosis of Tumor Cells

Melanoma is a malignant skin tumor with high metastatic activity. Although melanoma has been well-studied, its cellular kinetics remain elusive. The cholecystokinin (CCK) receptor is expressed in various types of tumors because CCK promotes the survival and proliferation of tumor cells. Thus, we hypothesized that the growth of melanoma was positively regulated by signals from the CCK receptor and sought to investigate whether CCK receptor antagonists affect the growth of melanoma cells expressing CCK receptor. Immunohistochemically, the CCK receptor A is expressed in the clinical specimens of melanoma. CCK receptor antagonists decreased the viability of melanoma cells by suppressing cell division and promoting apoptosis. CCK receptor antagonists also decreased the mitochondrial membrane potential through enhanced gene expression of the proapoptotic protein, Bcl2-associated X, and tumor suppressor, p53, suggesting that the antagonist induced the apoptosis of melanoma cells in a mitochondria-dependent manner. In addition, a caspase 3 inhibitor, Z-DEVD-FMK, partially blocked the antiviability of the antagonist, indicating that caspase 3 is involved in antagonist-induced apoptosis. Notably, tumor growth was attenuated when a CCK receptor antagonist was locally administered to the melanoma-bearing mice. Therefore, our study suggests the therapeutic potential of CCK receptor antagonists in the treatment of skin cancer.

MiR-767-3p suppresses melanoma progression by inhibiting ASF1B expression

BackgroundMelanoma, the type of skin cancer considered as most malignant, and known to be linked with a high incidence as well as high mortality rate. Although the dysregulation of ASF1B and miR-767-3p expression is involved in the progression of various cancers, their biological function in melanoma remains unclear. MethodsReal-time qPCR was the primary source for determining the levels of ASF1B and miR-767-3p in melanoma. For the validation of association among miR-767-3p and ASF1B, luciferase activity assay was used. Quantification of cell apoptosis, proliferation, migration and viability in melanoma cells were carried out by flow cytometry, BrdU, transwell assays, and CCK-8, respectively. Further evaluation of tumor growth was achieved by xenograft in vivo. ResultsResults showed an increased expression of ASF1B while declined expression of miR-767-3p in melanoma. ASF1B knockdown repressed cell migration, viability, proliferation, and tumor growth whereas boosted apoptosis in A375 as well as in A875 melanoma cells. Moreover, miR-767-3p attenuated the migration and proliferation of melanoma cells and encouraged cell apoptosis by reducing ASF1B levels. ConclusionIn this study, miR-767-3p was shown to inhibit ASF1B which will attenuate melanoma tumorigenesis, and by this it can be a potential new effective biomarker for the treatment of melanoma.

Synthesis and anti-melanoma effect of 3-O-prenyl glycyrrhetinic acid against B16F10 cells via induction of endoplasmic reticulum stress-mediated autophagy through ERK/AKT signaling pathway.

Melanoma is an aggressive form of cancer with poor prognosis and survival rates and limited therapeutic options. Here, we report the anti-melanoma effect of 3-O-prenyl glycyrrhetinic acid (NPC-402), a derivative of glycyrrhtinic acid, from a reputed medicinal plant Glycyrrhiza glabra against B16F10 cells. We studied the cytotoxic effect of NPC-402 on melanoma cells and investigated the role of mitogen-activated protein (MAP) kinase, AKT axis, and endoplasmic reticulum (ER) stress/unfolded protein response (UPR)-mediated autophagy as the involved signaling cascade by studying specific marker proteins. In this study, 4-phenylbutyric acid (4PBA, a chemical chaperone) and small interference RNA (siRNA) knockdown of C/EBP Homologous Protein (CHOP)/growth arrest- and DNA damage-inducible gene 153(GAD153) blocked NPC-402-mediated autophagy induction, thus confirming the role of ER stress and autophagy in melanoma cell death. NPC-402 induced oxidative stress and apoptosis in melanoma cells, which were effectively mitigated by treatment with N-acetylcysteine (NAC). In vivo studies showed that intraperitoneal (i.p.) injection of NPC-402 at 10 mg/kg (5 days in 1 week) significantly retarded angiogenesis in the Matrigel plug assay and reduced the tumor size and tumor weight without causing any significant toxic manifestation in C57BL/6J mice. We conclude that NPC-402 has a high potential to be developed as a chemotherapeutic drug against melanoma.

Bone Marrow Mesenchymal Stem Cell (BMSC) Downregulates Vascular Endothelial Growth Factor (VEGF) and Promotes the Apoptosis of Melanoma Cells

This study assessed BMSC’s effect on melanoma cells. The melanoma A375 cells were assigned into blank group, BMSC group, ERK agonist group, AKT agonist group, ERK + AKT agonist group and ERK + AKT repressor group followed by analysis of VEGF expression, cell apoptotic rate, and the expression of MEK/ERK and PI3K/AKT signal proteins. ERK and AKT agonist group showed highest VEGF expression, lowest cell apoptosis and Bcl-2 and Bcl-2/Bax expression as well as highest MEK/ERK and PI3K/AKT signaling proteins followed by ERK agonist group and AKT agonist group. The apoptosis of melanoma cells could be prompted by BMSC which might be through restraining the activity of MEK/ERK and PI3K/AKT signal pathway. In conclusion, the apoptosis of melanoma cells is prompted by BMSC through restraining the activity of MEK/ERK and PI3K/AKT signal pathway, indicating that BMSC might be used as a novel approach for the treatment of melanoma.

Iron oxide nanoparticles coated with polydopamine as a potential nano-photothermal agent for treatment of melanoma cancer: an in vivo study.

Melanoma is a metastatic cancer resistant to a wide range of therapies, including standard chemotherapy and radiation therapy, and cannot be treated with existing treatments owing to its intrinsic drug resistance. In terms of convenience and cheap cost of fabrication, one of the novel treatments is using polydopamine-coated iron oxide nanoparticles (IONs@PDA). Iron oxide nanoparticles (IONs) were synthesized (7.36nm) and coated with polydopamine (15-20nm). To examine the effect of photothermal ablation in melanoma cells (B16-F10), a Q-switched ruby laser (λ = 694nm, spot size = 4mm, output power = 5J/s) was used. The prepared nanoprobe was applied to mice, and their survival after treatment was evaluated. Then histopathological studies were done on the livers and skins of the treated mice. The nanoparticles absorb the laser, raising the temperature and initiating photothermal treatment, with significant apoptosis (74%) after the 4th time of treatment. Photothermal therapy (PTT) by using IONs@PDA proved to be effective in the treatment of melanoma cells (tumor size of < 2mm) without side effects. The lifespan of mice was significantly increased in a group of mice post-administered IONs@PDA and laser ablation. The fabricated nanoprobe (IONs@PDA) enhanced the melanoma cell apoptosis in the mice model, and it has promise for the treatment of melanoma (B16-F10) cells using photothermal therapy.

Cytoglobin inhibits non-thermal plasma-induced apoptosis in melanoma cells through regulation of the NRF2-mediated antioxidant response

Melanoma arises from pigment-producing cells called melanocytes located in the basal layers of the epidermis of the skin. Cytoglobin (CYGB) is a ubiquitously expressed hexacoordinated globin that is highly enriched in melanocytes and frequently downregulated during melanomagenesis. Previously, we showed that non-thermal plasma (NTP)-produced reactive oxygen and nitrogen species (RONS) lead to the formation of an intramolecular disulfide bridge that would allow CYGB to function as a redox-sensitive protein. Here, we investigate the cytotoxic effect of indirect NTP treatment in two melanoma cell lines with divergent endogenous CYGB expression levels, and we explore the role of CYGB in determining treatment outcome. Our findings are consistent with previous studies supporting that NTP cytotoxicity is mediated through the production of RONS and leads to apoptotic cell death in melanoma cells. Furthermore, we show that NTP-treated solutions elicit an antioxidant response through the activation of nuclear factor erythroid 2–related factor 2 (NRF2). The knockdown and overexpression of CYGB respectively sensitizes and protects melanoma cells from RONS-induced apoptotic cell death. The presence of CYGB enhances heme-oxygenase 1 (HO-1) and NRF2 protein expression levels, whereas the absence impairs their expression. Moreover, analysis of the CYGB-dependent transcriptome demonstrates the tumor suppressor long non-coding RNA maternally expressed 3 (MEG3) as a hitherto undescribed link between CYGB and NRF2. Thus, the presence of CYGB, at least in melanoma cells, seems to play a central role in determining the therapeutic outcome of RONS-inducing anticancer therapies, like NTP-treated solutions, possessing both tumor-suppressive and oncogenic features. Hence, CYGB expression could be of interest either as a biomarker or as a candidate for future targeted therapies in melanoma.

Onset of p53/NF-κB signaling crosstalk in human melanoma cells in response to anti-cancer theabrownin.

As a major tea component, theabrownin represents a promising anti-cancer candidate. However, its effect on the melanoma is unknown. To evaluate the in vitro and in vivo anti-melanoma efficacy of TB, we conducted cell viability, immunostaining, comet, and TUNEL assays on human A375 melanoma cells, and employed a zebrafish xenograft model of A375 cells. Real-time PCR (qPCR) and western blot were conducted to explore the molecular mechanisms of TB. In vitro, TB significantly inhibited the proliferation of A375 cells, and A375 cells showed the highest inhibitory rate among the other melanoma cell line (A875) and human dermal fibroblasts. TB triggered DNA damage and induced apoptosis of A375 cells and significantly inhibited the growth of A375 xenograft tumors in zebrafishes. Several key molecular events were activated by TB, including DNA damage-associated p53 and NF-κB pathways, through up-regulation of GADD45α, γ-H2A.X, phospho-ATM(p-ATM), phospho-ATR (p-ATR), phospho-p53 (p-p53), phospho-IKKα/β (p-IKKα/β), phospho-p65 (p-p65), etc. However, the TB-activated molecular events were counteracted by either knockdown of p53 or p65, and only dual knockdown of both p53 and p65 completed counteracted the anti-melanoma efficacy of TB. In conclusion, TB triggered DNA damage and thereby inhibited proliferation and induced cellular senescence and apoptosis of melanoma cells through mechanisms mediated by p53/NF-κB signaling crosstalk. This is the first report on the efficacy and mechanisms of TB on melanoma cells, making TB a promising candidate for anti-melanoma agent development.

Electrospun Membranes Designed for Burst Release of New Gold-Complexes Inducing Apoptosis of Melanoma Cells.

Two non-commercial metallic Au-based complexes were tested against one of the most aggressive malignant melanomas of the skin (MeWo cells), through cell viability and time-lapse live-cell imaging system assays. The tests with the complexes were carried out both in the form of free metallic complexes, directly in contact with the MeWo cell line culture, and embedded in fibers of Polycaprolactone (PCL) membranes produced by the electrospinning technique. Membranes functionalized with complexes were prepared to evaluate the efficiency of the membranes against the melanoma cells and therefore their feasibility in the application as an antitumoral patch for topical use. Both series of tests highlighted a very effective antitumoral activity, manifesting a very relevant cell viability inhibition after both 24 h and 48 h. In the case of the AuM1 complex at the concentration of 20 mM, melanoma cells completely died in this short period of time. A mortality of around 70% was detected from the tests performed using the membranes functionalized with AuM1 complex at a very low concentration (3 wt.%), even after 24 h of the contact period. The synthesized complexes also manifest high selectivity with respect to the MeWo cells. The peculiar structural and morphological organization of the nanofibers constituting the membranes allows for a very effective antitumoral activity in the first 3 h of treatment. Experimental points of the release profiles were perfectly fitted with theoretical curves, which easily allow interpretation of the kinetic phenomena occurring in the release of the synthesized complexes in the chosen medium.

Modulation of A375 human melanoma cell proliferation and apoptosis by nitric oxide

The present study aimed to assess the effect of NO• on melanoma A375 cell growth and apoptotic cell death. Trypan blue exclusion assay was employed to detect the cytotoxicity induced by controlled steady-state concentrations (given in µM • min) of NO•. The characteristics of the cellular cell cycle and apoptosis in NO•-treated A375 cells were also analyzed by Annexin V/PI and DNA fragmentation assays. Western blotting was applied to detect the expression of apoptosis-related proteins (p53, Bax, Fas, DR5, caspase-3 and -9, and PARP). When exposed to preformed 100% NO• for 8 h reactor system, a cumulative dose of 3360 μM • min reduced the viability by 22% 24 h after treatment and promoted apoptosis, 2.9- and 12.2-folds 24 and 48 h after treatment higher than the argon control, respectively. Cell cycle analysis 48 h after treatment revealed S-phase arrest in cells treated with 3360 μM • min NO•. It was also observed that the expression of p53, DR5, caspase 9 and PARP increased significantly upon NO• treatment. In addition, the present study assessed the inhibitory effects of endogenous NO• on the proliferation of human melanoma cells by employing specific (AMG, 1400W and/or SMTC) and nonspecific (NMA) NO• synthase (NOS) inhibitors resulting in melanoma cell growth inhibition; the highest cytotoxic effect was seen when inducible NOS inhibition by 1 mM 1400W treatment. Collectively, the present data suggest that NO• is involved in a key mechanism limiting melanoma proliferation and apoptosis, which may play in improving the efficacy of melanoma treatment.

Anti-Tumor Effect of IDF-11774, an Inhibitor of Hypoxia-Inducible Factor-1, on Melanoma.

Melanoma is one of the most aggressive skin cancers. Hypoxia contributes to the aggressiveness of melanoma by promoting cancer growth and metastasis. Upregulation of cyclin D1 can promote uncontrolled cell proliferation in melanoma, whereas stimulation of cytotoxic T cell activity can inhibit it. Epithelial mesenchymal transition (EMT) plays a critical role in melanoma metastasis. Hypoxia-inducible factor-1α (HIF-1α) is a main transcriptional mediator that regulates many genes related to hypoxia. CoCl2 is one of the most commonly used hypoxia-mimetic chemicals in cell culture. In this study, inhibitory effects of IDF-11774, an inhibitor of HIF-1α, on melanoma growth and metastasis were examined using cultured B16F10 mouse melanoma cells and nude mice transplanted with B16F10 melanoma cells in the presence or absence of CoCl2-induced hypoxia. IDF-11774 reduced HIF-1α upregulation and cell survival, but increased cytotoxicity of cultured melanoma cells under CoCl2-induced hypoxia. IDF-11774 also reduced tumor size and local invasion of B16F10 melanoma in nude mice along with HIF-1α downregulation. Expression levels of cyclin D1 in melanoma were increased by CoCl2 but decreased by IDF-11774. Apoptosis of melanoma cells and infiltration of cytotoxic T cells were increased in melanoma after treatment with IDF-11774. EMT was stimulated by CoCl2, but restored by IDF-11774. Overall, IDF-11774 inhibited the growth and metastasis of B16F10 melanoma via HIF-1α downregulation. The growth of B16F10 melanoma was inhibited by cyclin D1 downregulation and cytotoxic T cell stimulation. Metastasis of B16F10 melanoma was inhibited by EMT suppression.