The MAPK pathway in melanoma. Curr Opin Oncol. 2008;20:183-189. [PMID: 18300768 DOI: 10.1097/CCO.0b013e3282f5271c]

eIF4F controls ERK MAPK signaling in melanomas with BRAF and NRAS mutations

The eIF4F translation initiation complex plays a critical role in melanoma resistance to clinical BRAF and MEK inhibitors. In this study, we uncover a function of eIF4F in the negative regulation of the rat sarcoma (RAS)/rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathway. We demonstrate that eIF4F is essential for controlling ERK signaling intensity in treatment-naïve melanoma cells harboring BRAF or NRAS mutations. Specifically, the dual-specificity phosphatase DUSP6/MKP3, which acts as a negative feedback regulator of ERK activity, requires continuous production in an eIF4F-dependent manner to limit excessive ERK signaling driven by oncogenic RAF/RAS mutations. Treatment with small-molecule eIF4F inhibitors disrupts the negative feedback control of MAPK signaling, leading to ERK hyperactivation and EGR1 overexpression in melanoma cells in vitro and in vivo. Furthermore, our quantitative analyses reveal a high spare signaling capacity in the ERK pathway, suggesting that eIF4F-dependent feedback keeps the majority of ERK molecules inactive under normal conditions. Overall, our findings highlight the crucial role of eIF4F in regulating ERK signaling flux and suggest that pharmacological eIF4F inhibitors can disrupt the negative feedback control of MAPK activity in melanomas with BRAF and NRAS activating mutations.

Targeted Therapy Innovations for Melanoma

Melanoma, a malignant tumor of melanocytes, poses a significant clinical challenge due to its aggressive nature and high potential for metastasis. The advent of targeted therapy has revolutionized the treatment landscape of melanoma, particularly for tumors harboring specific genetic alterations such as BRAF V600E mutations. Despite the initial success of targeted agents, resistance inevitably arises, underscoring the need for novel therapeutic strategies. This review explores the latest advances in targeted therapy for melanoma, focusing on new molecular targets, combination therapies, and strategies to overcome resistance.

Radioprotective effect of polyvinylpyrrolidone modified selenium nanoparticles and its antioxidation mechanism in vitro and in vivo

Objective

Polyvinylpyrrolidone (PVP) is a commonly used biomedical polymer material with good water solubility, biocompatibility, low immunogenicity, and low toxicity. The aim of this study is to investigate the antioxidant mechanism and clinical potential of PVP modified selenium nanoparticles (PVP-Se NPs) as a new radioprotective agent.

Methods

A laser particle size analyzer and transmission electron microscope were used to characterize PVP-Se nanoparticles prepared by chemical reduction. Human umbilical vein endothelial cells (HUVECs) were used to evaluate the radiation protective effects of PVP-Se NPs. SD rats were employed as an in vivo model to identify the most effective concentration of PVP-Se NPs and assess their potential radioprotective properties. Western blot (WB) was used to detect the expression of nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling proteins in human umbilical vein endothelial cells (HUVECs) and rat liver and kidney tissues.

Results

PVP-Se NPs could reduce the oxidative stress injury and inflammatory response caused by X-ray irradiation in HUVECs and rats, and inhibit cell apoptosis by modulating NF-κB and MAPK signaling pathways. PVP-Se NPs could increase HUVECs viability, reduce apoptosis, inhibit inflammatory factors IL-1β, IL-6 and TNF-α, improve the survival rate of rats, promote antioxidant enzyme activities in cells and rats, reduce malondialdehyde concentration in serum, and reduce the expression of inflammatory factors such as IL-1β, IL-6 and TNF-α in cell supernatant and liver and kidney tissues. PVP-Se NPs could significantly reduce the phosphorylation levels of NF-κB and MAPK pathway-associated proteins in HUVECs and rat liver and kidney tissues (p < 0.05).

Conclusion

PVP-Se NPs can protect against radiation-induced oxidative damage by modulating NF-kB and MAPK pathways, providing a theoretical basis and experimental data for their use as an effective radioprotective agent.

Ferroptosis and circular RNAs: new horizons in cancer therapy

Cancer poses intricate challenges to treatment due to its complexity and diversity. Ferroptosis and circular RNAs (circRNAs) are emerging as innovative therapeutic avenues amid the evolving landscape of cancer therapy. Extensive investigations into circRNAs reveal their diverse roles, ranging from molecular regulators to pivotal influencers of ferroptosis in cancer cell lines. The results underscore the significance of circRNAs in modulating molecular pathways that impact crucial aspects of cancer development, including cell survival, proliferation, and metastasis. A detailed analysis delineates these pathways, shedding light on the molecular mechanisms through which circRNAs influence ferroptosis. Building upon recent experimental findings, the study evaluates the therapeutic potential of targeting circRNAs to induce ferroptosis. By identifying specific circRNAs associated with the etiology of cancer, this analysis paves the way for the development of targeted therapeutics that exploit vulnerabilities in cancer cells. This review consolidates the existing understanding of ferroptosis and circRNAs, emphasizing their role in cancer therapy and providing impetus for ongoing research in this dynamic field. See also the graphical abstract(Fig. 1).

Precise Readout of MEK1 Proteoforms upon MAPK Pathway Modulation by Individual Ion Mass Spectrometry

The functions of proteins bearing multiple post-translational modifications (PTMs) are modulated by their modification patterns, yet precise characterization of them is difficult. MEK1 (also known as MAP2K1) is one such example that acts as a gatekeeper of the mitogen-activating protein kinase (MAPK) pathway and propagates signals via phosphorylation by upstream kinases. In principle, top-down mass spectrometry can precisely characterize whole MEK1 proteoforms, but fragmentation methods that would enable the site-specific characterization of labile modifications on 43 kDa protein ions result in overly dense tandem mass spectra. By using the charge-detection method called individual ion mass spectrometry, we demonstrate how complex mixtures of phosphoproteoforms and their fragment ions can be reproducibly handled to provide a "bird's eye" view of signaling activity through mapping proteoform landscapes in a pathway. Using this approach, the overall stoichiometry and distribution of 0-4 phosphorylations on MEK1 was determined in a cellular model of drug-resistant metastatic melanoma. This approach can be generalized to other multiply modified proteoforms, for which PTM combinations are key to their function and drug action.

Incorporating network diffusion and peak location information for better single-cell ATAC-seq data analysis

Single-cell assay for transposase-accessible chromatin using sequencing (scATAC-seq) data provided new insights into the understanding of epigenetic heterogeneity and transcriptional regulation. With the increasing abundance of dataset resources, there is an urgent need to extract more useful information through high-quality data analysis methods specifically designed for scATAC-seq. However, analyzing scATAC-seq data poses challenges due to its near binarization, high sparsity and ultra-high dimensionality properties. Here, we proposed a novel network diffusion-based computational method to comprehensively analyze scATAC-seq data, named Single-Cell ATAC-seq Analysis via Network Refinement with Peaks Location Information (SCARP). SCARP formulates the Network Refinement diffusion method under the graph theory framework to aggregate information from different network orders, effectively compensating for missing signals in the scATAC-seq data. By incorporating distance information between adjacent peaks on the genome, SCARP also contributes to depicting the co-accessibility of peaks. These two innovations empower SCARP to obtain lower-dimensional representations for both cells and peaks more effectively. We have demonstrated through sufficient experiments that SCARP facilitated superior analyses of scATAC-seq data. Specifically, SCARP exhibited outstanding cell clustering performance, enabling better elucidation of cell heterogeneity and the discovery of new biologically significant cell subpopulations. Additionally, SCARP was also instrumental in portraying co-accessibility relationships of accessible regions and providing new insight into transcriptional regulation. Consequently, SCARP identified genes that were involved in key Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to diseases and predicted reliable cis-regulatory interactions. To sum up, our studies suggested that SCARP is a promising tool to comprehensively analyze the scATAC-seq data.

Effects of µ-Conotoxin GIIIB on the cellular activity of mouse skeletal musculoblast: combined transcriptome and proteome analysis

µ-Conotoxin GIIIB (µ-CTX GIIIB) is a polypeptide containing three disulfide bridges, produced by the sea snail Conus geographus. This study was aimed to explored the cytotoxic effects of µ-CTX GIIIB on mouse skeletal musculoblast (Sol8). Sol8 cells were exposed to ouabain and veratridine to establish the cell injury model, and then treated with µ-CTX GIIIB. CCK-8 was adopted to evaluate the cytotoxicity of µ-CTX GIIIB. Then, proteomics and transcriptome were conducted, and the explore the differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) affected by µ-CTX GIIIB were found. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was used to investigate the affected signaling pathways. µ-CTX GIIIB increased the cell survival rate of injured Sol8 cells. We found and identified 1,663 DEGs and 444 DEPs influenced by µ-CTX GIIIB. 106 pairs of correlated DEGs and DEPs were selected by combining transcriptome and proteome data. The results of KEGG and GO analysis showed that µ-CTX GIIB affected the cell cycle, apoptosis, DNA damage and repair, lipid metabolism and other biological processes of Sol8 cells. µ-CTX GIIIB could affected cell cycle regulation, DNA damage repair, and activation of tumor factors, with potential carcinogenic effects. Our results provide an important basis for the study of in vitro toxicity, the mechanism of toxicity and injury prevention by µ-CTX GIIIB.

Targeting ferroptosis as a cell death pathway in Melanoma: From molecular mechanisms to skin cancer treatment

Melanoma, the most aggressive form of human skin cancer, has been under investigation to reach the most efficient treatment. Surgical resection for early-diagnosed primary melanoma, targeted therapies, and immune checkpoint inhibitors for advanced/metastatic melanoma is the best clinical approach. Ferroptosis, a newly identified iron-dependent cell death pathway, which is morphologically and biochemically different from apoptosis and necrosis, has been reported to be involved in several cancers. Ferroptosis inducers could provide therapeutic options in case of resistance to conventional therapies for advanced/metastatic melanoma. Recently developed ferroptosis inducers, MEK and BRAF inhibitors, miRNAs such as miR-137 and miR-9, and novel strategies for targeting major histocompatibility complex (MHC) class II in melanoma can provide new opportunities for melanoma treatment. Combining ferroptosis inducers with targeted therapies or immune checkpoint inhibitors increases patient response rates. Here we review the mechanisms of ferroptosis and its environmental triggers. We also discuss the pathogenesis and current treatments of melanoma. Moreover, we aim to elucidate the relationship between ferroptosis and melanoma and ferroptosis implications to develop new therapeutic strategies against melanoma.

Hypoxia in Skin Cancer: Molecular Basis and Clinical Implications

Skin cancer is one of the most prevalent cancers in the Caucasian population. In the United States, it is estimated that at least one in five people will develop skin cancer in their lifetime, leading to significant morbidity and a healthcare burden. Skin cancer mainly arises from cells in the epidermal layer of the skin, where oxygen is scarce. There are three main types of skin cancer: malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Accumulating evidence has revealed a critical role for hypoxia in the development and progression of these dermatologic malignancies. In this review, we discuss the role of hypoxia in treating and reconstructing skin cancers. We will summarize the molecular basis of hypoxia signaling pathways in relation to the major genetic variations of skin cancer.

Phytochemical Constituents and Derivatives of Cannabis sativa; Bridging the Gap in Melanoma Treatment

Melanoma is deadly, physically impairing, and has ongoing treatment deficiencies. Current treatment regimens include surgery, targeted kinase inhibitors, immunotherapy, and combined approaches. Each of these treatments face pitfalls, with diminutive five-year survival in patients with advanced metastatic invasion of lymph and secondary organ tissues. Polyphenolic compounds, including cannabinoids, terpenoids, and flavonoids; both natural and synthetic, have emerging evidence of nutraceutical, cosmetic and pharmacological potential, including specific anti-cancer, anti-inflammatory, and palliative utility. Cannabis sativa is a wellspring of medicinal compounds whose direct and adjunctive application may offer considerable relief for melanoma suffers worldwide. This review aims to address the diverse applications of C. sativa's biocompounds in the scope of melanoma and suggest it as a strong candidate for ongoing pharmacological evaluation.

Interactions of melatonin with various signaling pathways: implications for cancer therapy

Melatonin is a neuro-hormone with conserved roles in evolution. Initially synthetized as an antioxidant molecule, it has gained prominence as a key molecule in the regulation of the circadian rhythm. Melatonin exerts its effect by binding to cytoplasmic and intra-nuclear receptors, and is able to regulate the expression of key mediators of different signaling pathways. This ability has led scholars to investigate the role of melatonin in reversing the process of carcinogenesis, a process in which many signaling pathways are involved, and regulating these pathways may be of clinical significance. In this review, the role of melatonin in regulating multiple signaling pathways with important roles in cancer progression is discussed, and evidence regarding the beneficence of targeting malignancies with this approach is presented.

Olive leaf extract inhibits metastatic melanoma spread through suppression of epithelial to mesenchymal transition

Olive tree leaves are an abundant source of bioactive compounds with several beneficial effects for human health, including a protective role against many types of cancer. In this study, we investigated the effect of an extract, obtained from olive tree (Olea europaea L.) leaves (OLE), on proliferation, invasion, and epithelial to mesenchymal transition (EMT) on metastatic melanoma, the highly aggressive form of skin cancer and the deadliest diseases. Our results demonstrated that OLE inhibited melanoma cells proliferation through cell cycle arrest and induction of apoptotic cell death. Moreover, OLE suppressed the migration, invasion, and colonies formation of human melanoma cells. Similar to our in vitro findings, we demonstrated that the oral administration of OLE inhibited cutaneous tumor growth and lung metastasis formation in vivo by modulating the expression of EMT related factors. In addition, the anti-proliferative and anti-invasive effects of OLE against melanoma were also related to a simultaneous targeting of mitogen-activated protein kinase and PI3K pathways, both in vitro and in vivo. In conclusion, our findings suggest that OLE has the potential to inhibit the metastatic spread of melanoma cells thanks to its multifaceted mechanistic effects, and may represent a new add-on therapy for the management of metastatic melanoma.

Endogenous DOPA inhibits melanoma through suppression of CHRM1 signaling

Melanoma risk is 30 times higher in people with lightly pigmented skin versus darkly pigmented skin. Using primary human melanocytes representing the full human skin pigment continuum and preclinical melanoma models, we show that cell-intrinsic differences between dark and light melanocytes regulate melanocyte proliferative capacity and susceptibility to malignant transformation, independent of melanin and ultraviolet exposure. These differences result from dihydroxyphenylalanine (DOPA), a melanin precursor synthesized at higher levels in melanocytes from darkly pigmented skin. We used both high-throughput pharmacologic and genetic in vivo CRISPR screens to determine that DOPA limits melanocyte and melanoma cell proliferation by inhibiting the muscarinic acetylcholine receptor M1 (CHRM1) signaling. Pharmacologic CHRM1 antagonism in melanoma leads to depletion of c-Myc and FOXM1, both of which are proliferation drivers associated with aggressive melanoma. In preclinical mouse melanoma models, pharmacologic inhibition of CHRM1 or FOXM1 inhibited tumor growth. CHRM1 and FOXM1 may be new therapeutic targets for melanoma.

Oncogenic properties via MAPK signaling of the SOX5-RAF1 fusion gene identified in a wild-type NRAS/BRAF giant congenital nevus

We recently reported an RAF rearrangement without NRAS or BRAF mutations in lesions from Giant Congenital Melanocytic Nevi (CMN). The new gene fusion involves the 5'-end of the promoter-containing N terminus of the SOX5 gene fused to exons 7-16 of the 3'-end of RAF1 gene leading to a SOX5-RAF1 fusion transcript which loses the auto-inhibitory CR1 domain but retains the complete in-frame coding sequence for the C-Terminal kinase domain of the RAF1. Stable expression of SOX5-RAF1 fusion induced growth factor-independent cell growth in murine hematopoietic Ba/F3 cells and melan-a immortalized melanocytes. Besides, it led to the transformation of both Ba/F3 and NIH 3T3 cells as revealed by colony formation assays. Furthermore, its expression results in MAPK activation assessed by increased levels of p-ERK protein in the cytosol of transduced cells. Treatment with Sorafenib and UO126 inhibited proliferation of Ba/F3-SOX5-RAF1 cells in the absence of IL3 but not the PLX 4720, a specific inhibitor of BRAF. Moreover, the tumorigenic and metastatic capacities of SOX5-RAF1 were assessed in vivo. These results indicate that SOX5-RAF1, a driver event for CMN development, has oncogenic capacity. Thus, sequencing of CMN transcriptomes may lead to the identification of this druggable fusion and interfere with the progression toward melanoma.

Improving Homology-Directed Repair in Genome Editing Experiments by Influencing the Cell Cycle

Genome editing is currently widely used in biomedical research; however, the use of this method in the clinic is still limited because of its low efficiency and possible side effects. Moreover, the correction of mutations that cause diseases in humans seems to be extremely important and promising. Numerous attempts to improve the efficiency of homology-directed repair-mediated correction of mutations in mammalian cells have focused on influencing the cell cycle. Homology-directed repair is known to occur only in the late S and G2 phases of the cell cycle, so researchers are looking for safe ways to enrich the cell culture with cells in these phases of the cell cycle. This review surveys the main approaches to influencing the cell cycle in genome editing experiments (predominantly using Cas9), for example, the use of cell cycle synchronizers, mitogens, substances that affect cyclin-dependent kinases, hypothermia, inhibition of p53, etc. Despite the fact that all these approaches have a reversible effect on the cell cycle, it is necessary to use them with caution, since cells during the arrest of the cell cycle can accumulate mutations, which can potentially lead to their malignant transformation.

Integrating network pharmacology and non-targeted metabolomics to explore the common mechanism of Coptis Categorized Formula improving T2DM zebrafish

ETHNOPHARMACOLOGICAL RELEVANCE

Coptis Categorized Formula (CCF) is one of the core prescriptions in Treatise on Febrile Diseases. Its efficacy can be available not only in exogenous diseases but widely in various internal injuries and miscellaneous diseases. CCF (i.e., Huanglian Jiedu Decoction, Huanglian Ejiao Decoction, Dahuang Huanglian Xiexin Decoction, Gegen Qinlian Decoction) is different in composition, but they all play a favorable role in curative effect on type 2 diabetes mellitus (T2DM). Therefore, it is of great significance to reveal the common mechanism of CCF in treating T2DM.

AIM OF THE STUDY

Based on network pharmacology and non-targeted metabolomics research strategy, the common mechanism of the CCF treating T2DM was discussed.

MATERIALS AND METHODS

Firstly, Ultra-high performance liquid chromatography-quadrupole-time of flight/mass spectrometry was used to identify the chemical constituents of the CCF. Then, the targets of these chemical components were used for network pharmacology analysis associated with therapeutic effect. Finally, the diabetic zebrafish model was constructed to further verify the common mechanism of the CCF in treating T2DM.

RESULTS

A total of 160 chemical compositions were identified and 16 of them were common chemical compositions of the four CCF, including berberine, baicalin, coptisine and so forth. Network pharmacology results showed that Dipeptidyl peptidase (DPP)-4, cysteinyl aspartate specific proteinase (CASP)3, nitric oxide synthase (NOS)2, NOS3, and other 37 targets were common targets of CCF, and advanced glycation end products (AGE)-receptor of advanced glycation end products (RAGE) signaling pathway in diabetic complications, mitogen-activated protein kinase (MAPK) signaling pathway and hypoxia inducible factor (HIF)-1 signaling pathway were critical pathways of four CCF in the treatment of T2DM. CCF can lessen the blood glucose of diabetic zebrafish. The contents of 25 differential metabolites in diabetic zebrafish were altered. These metabolites were mainly related to phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine metabolism, arachidonic acid metabolism, sphingolipid metabolism, and tyrosine metabolism.

CONCLUSION

Our research shows that the common mechanism of CCF in improving T2DM is as follows: berberine, baicalin, coptisine and other chemical components can directionally regulate DPP-4, CASP3, NOS2, NOS3 and other targets, which are mediated by AGE-RAGE signaling pathway in diabetic complications, MAPK signaling pathway and HIF-1 signaling pathway. The content of endogenous metabolites such as L-valine and L-sorbitose changes, and further regulates the metabolism of amino acid metabolism, lipid metabolism, purine metabolism, sphingosine metabolism and arachidonic acid metabolism, so as to play a significant role in regulating glycolipid metabolism, improving insulin resistance, inhibiting cell apoptosis, anti-oxidation and anti-inflammation, and finally ameliorating T2DM.

Protective effect of Apremilast against LPS-induced acute lung injury via modulation of oxidative stress and inflammation: Possible involvement of Akt and ERK signaling pathways

Lung injuries are attributed due to exposure to Drugs or chemicals. One of the important challenging situations for the clinicians is to manage treatments of different diseases with acute lung injury (ALI). The objective of this study was to investigate the possible protective mechanisms and action of a novel Phosphodiesterase-4 inhibitor “Apremilast” (AP) in lipopolysaccharide (LPS)-induced lung injury. Blood sample from each animals were collected in a vacuum blood collection tube. The rat lungs were isolated for oxidative stress assessment, western blot analysis and their mRNA expressions using RT-PCR. Exposure of LPS in rats causes significant increase in oxidative stress, activates the pro-inflammatory cytokines release like tissue necrotic factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), modulated gene expression, protein expression and histopathological changes which were reversed by administration of AP. Finding of the research enlighten the protective role of AP against LPS-induced ALI.

Ononin ameliorates inflammation and cartilage degradation in rat chondrocytes with IL-1β-induced osteoarthritis by downregulating the MAPK and NF-κB pathways

BACKGROUND

Osteoarthritis (OA) treatment aims to improve inflammation and delay cartilage degeneration. However, there is no effective strategy presently available. Ononin, a representative isoflavone glycoside component extracted from natural Chinese herbs, exerts anti-inflammatory and proliferative effects. However, the therapeutic effect of ononin on chondrocyte inflammation remains unclear.

METHODS

In this study, we explored the therapeutic effect and potential mechanism of ononin in OA by establishing an interleukin-1 beta (IL-1β)-induced chondrocyte inflammation model.

RESULTS

Our results verified that ononin alleviated the IL-1β-induced decrease in chondrocyte viability, attenuated the overexpression of the inflammatory factors tumour necrosis factor α (TNF-α) and interleukin 6 (IL-6), and simultaneously inhibited the expression of cartilage extracellular matrix (ECM)-degrading enzymes such as matrix metalloproteinase-13 (MMP-13). Furthermore, the decomposition of Collagen II protein could be alleviated in the OA model by ononin. Finally, ononin improved chondrocyte inflammation by downregulating the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signalling pathways.

CONCLUSION

Our findings suggested that ononin could inhibit the IL-1β-induced proinflammatory response and ECM degradation in chondrocytes by interfering with the abnormal activation of the MAPK and NF-κB pathways, indicating its protective effect against OA.

Crosstalk with keratinocytes causes GNAQ oncogene specificity in melanoma

Different melanoma subtypes exhibit specific and non-overlapping sets of oncogene and tumor suppressor mutations, despite a common cell of origin in melanocytes. For example, activation of the Gα_q/11 signaling pathway is a characteristic initiating event in primary melanomas that arise in the dermis, uveal tract, or central nervous system. It is rare in melanomas arising in the epidermis. The mechanism for this specificity is unknown. Here, we present evidence that in the mouse, crosstalk with the epidermal microenvironment actively impairs the survival of melanocytes expressing the GNAQ^Q209L oncogene. We found that GNAQ^Q209L, in combination with signaling from the interfollicular epidermis (IFE), stimulates dendrite extension, leads to actin cytoskeleton disorganization, inhibits proliferation, and promotes apoptosis in melanocytes. The effect was reversible and paracrine. In contrast, the epidermal environment increased the survival of wildtype and Braf^V600E expressing melanocytes. Hence, our studies reveal the flip side of Gα_q/11 signaling, which was hitherto unsuspected. In the future, the identification of the epidermal signals that restrain the GNAQ^Q209L oncogene could suggest novel therapies for GNAQ and GNA11 mutant melanomas.

IGF1R/IR Mediates Resistance to BRAF and MEK Inhibitors in BRAF-Mutant Melanoma

Simple Summary

Melanoma accounts for only 4% of skin cancer, but is the major cause of skin cancer related deaths. The use of dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor), two FDA approved drugs to treat patients with BRAFV600E melanoma, is limited in the clinic due to the development of resistance. The IGF family of receptors is known to play a crucial role in cancer progression. In our in vitro screening, we identified that the activation of Insulin-like growth factor 1 receptor (IGF1R) and Insulin Receptor (IR) mediates resistance to dabrafenib and trametinib. Patients with high levels of IGF1R and IR have worse survival outcomes compared to patients with low levels of these receptors. We demonstrate that combining dabrafenib and trametinib with an IGF1R/IR inhibitor, BMS-754807, in vitro and in vivo, is efficacious and inhibits proliferation and tumor growth. This research opens up avenues for the development of novel and potent IGF1R/IR inhibitors for patients with BRAF-mutant melanoma.

Abstract

The use of BRAF and MEK inhibitors for patients with BRAF-mutant melanoma is limited as patients relapse on treatment as quickly as 6 months due to acquired resistance. We generated trametinib and dabrafenib resistant melanoma (TDR) cell lines to the MEK and BRAF inhibitors, respectively. TDR cells exhibited increased viability and maintenance of downstream p-ERK and p-Akt as compared to parental cells. Receptor tyrosine kinase arrays revealed an increase in p-IGF1R and p-IR in the drug resistant cells versus drug sensitive cells. RNA-sequencing analysis identified IGF1R and INSR upregulated in resistant cell lines compared to parental cells. Analysis of TCGA PanCancer Atlas (skin cutaneous melanoma) showed that patients with a BRAF mutation and high levels of IGF1R and INSR had a worse overall survival. BMS-754807, an IGF1R/IR inhibitor, suppressed cell proliferation along with inhibition of intracellular p-Akt in TDR cells. Dual inhibition of IGF1R and INSR using siRNA reduced cell proliferation. The combination of dabrafenib, trametinib, and BMS-754807 treatment reduced in vivo xenograft tumor growth. Examining the role of IGF1R and IR in mediating resistance to BRAF and MEK inhibitors will expand possible treatment options to aid in long-term success for BRAF-mutant melanoma patients.

Spatially resolved transcriptomics reveals the architecture of the tumor-microenvironment interface

During tumor progression, cancer cells come into contact with various non-tumor cell types, but it is unclear how tumors adapt to these new environments. Here, we integrate spatially resolved transcriptomics, single-cell RNA-seq, and single-nucleus RNA-seq to characterize tumor-microenvironment interactions at the tumor boundary. Using a zebrafish model of melanoma, we identify a distinct "interface" cell state where the tumor contacts neighboring tissues. This interface is composed of specialized tumor and microenvironment cells that upregulate a common set of cilia genes, and cilia proteins are enriched only where the tumor contacts the microenvironment. Cilia gene expression is regulated by ETS-family transcription factors, which normally act to suppress cilia genes outside of the interface. A cilia-enriched interface is conserved in human patient samples, suggesting it is a conserved feature of human melanoma. Our results demonstrate the power of spatially resolved transcriptomics in uncovering mechanisms that allow tumors to adapt to new environments.

Design, Synthesis and Anticancer Profile of New 4-(1H-benzo[d]imidazol-1-yl)pyrimidin-2-amine-Linked Sulfonamide Derivatives with V600EBRAF Inhibitory Effect

A new series of 4-(1H-benzo[d]imidazol-1-yl)pyrimidin-2-amine linked sulfonamide derivatives 12a–n was designed and synthesized according to the structure of well-established V600EBRAF inhibitors. The terminal sulfonamide moiety was linked to the pyrimidine ring via either ethylamine or propylamine bridge. The designed series was tested at fixed concentration (1 µM) against V600EBRAF, finding that 12e, 12i and 12l exhibited the strongest inhibitory activity among all target compounds and 12l had the lowest IC₅₀ of 0.49 µM. They were further screened on NCI 60 cancer cell lines to reveal that 12e showed the most significant growth inhibition against multiple cancer cell lines. Therefore, cell cycle analysis of 12e was conducted to investigate the effect on cell cycle progression. Finally, virtual docking studies was performed to gain insights for the plausible binding modes of vemurafenib, 12i, 12e and 12l.

Canonical Signaling Pathways in Melanoma

Melanoma is the most lethal type of skin cancer, originating from the uncontrolled proliferation of melanocytes. The transformation of normal melanocytes into malignant tumor cells has been a focus of research seeking to better understand melanoma's pathogenesis and develop new therapeutic targets. Over the past few decades, a conglomeration of studies has pinpointed several driver mutations and their associated signaling pathways. In this review, we summarize the key signaling pathways and the driver mutations involved in melanoma tumorigenesis and also discuss the potential underlying mechanisms.

Fermitin family member 2 promotes melanoma progression by enhancing the binding of p-α-Pix to Rac1 to activate the MAPK pathway

We identified fermitin family member 2 (FERMT2, also known as kindlin-2) as a potential target in A375 cell line by siRNA library screening. Drugs that target mutant BRAF kinase lack durable efficacy in the treatment of melanoma because of acquired resistance, thus the identification of novel therapeutic targets is needed. Immunohistochemistry was used to identify kindlin-2 expression in melanoma samples. The interaction between kindlin-2 and Rac1 or p-Rac/Cdc42 guanine nucleotide exchange factor 6 (α-Pix) was investigated. Finally, the tumor suppressive role of kindlin-2 was validated in vitro and in vivo. Analysis of clinical samples and Oncomine data showed that higher levels of kindlin-2 predicted a more advanced T stage and M stage and facilitated metastasis and recurrence. Kindlin-2 knockdown significantly inhibited melanoma growth and migration, whereas kindlin-2 overexpression had the inverse effects. Further study showed that kindlin-2 could specifically bind to p-α-Pix(S13) and Rac1 to induce a switch from the inactive Rac1-GDP conformation to the active Rac1-GTP conformation and then stimulate the downstream MAPK pathway. Moreover, we revealed that a Rac1 inhibitor suppressed melanoma growth and metastasis and the combination of the Rac1 inhibitor and vemurafenib resulted in a better therapeutic outcome than monotherapy in melanoma with high kindlin-2 expression and BRAF mutation. Our results demonstrated that kindlin-2 promoted melanoma progression, which was attributed to specific binding to p-α-Pix(S13) and Rac1 to stimulate the downstream MAPK pathway. Thus, kindlin-2 could be a potential therapeutic target for treating melanoma.

A Review of Epidemiology and Cancer Biology of Malignant Melanoma

Malignant melanoma is a neoplasm originating in the melanocytes in the skin. Although malignant melanoma is the third most common cutaneous cancer, it is recognized as the main cause of skin cancer-related mortality, and its incidence is rising. The natural history of malignant melanoma involves an inconsistent and insidious skin cancer with great metastatic potential. Increased ultra-violet (UV) skin exposure is undoubtedly the greatest risk factor for developing cutaneous melanoma; however, a plethora of risk factors are now recognized as causative. Moreover, modern oncology now considers melanoma proliferation a complex, multifactorial process with a combination of genetic, epigenetic, and environmental factors all known to be contributory to tumorgenesis. Herein, we wish to outline the epidemiological, molecular, and biological processes responsible for driving malignant melanoma proliferation.

Ocoxin Increases the Antitumor Effect of BRAF Inhibition and Reduces Cancer Associated Fibroblast-Mediated Chemoresistance and Protumoral Activity in Metastatic Melanoma

Whereas the prevalence of several cancer types is decreasing, skin malignancies are growing more common every year. Malignant melanoma is the most aggressive form of skin cancer with high metastatic capacity. In most cases, malignant melanoma shows acquired therapy resistance. We evaluated the ability of Ocoxin, a natural compound-based antioxidant and anti-inflammatory nutritional complement, to exert an antitumor effect in melanoma. To do so, the cytotoxicity of Ocoxin in a panel of BRAF-mutated murine and human melanoma cell lines was tested alone and in combination with BRAF inhibitor Vemurafenib. Our results revealed a potent cytotoxic effect of Ocoxin against melanoma cells and a synergic effect when combined with Vemurafenib, reducing viability and increasing apoptosis. Besides, Ocoxin interferes with the cell cycle, impairs the inherent and fibroblast-mediated melanoma cell migration, and reduces resistance to BRAF inhibition. Proteomic analysis revealed reduced tumor secretion of inflammatory factors Galectin-1, Osteopontin, CCL5, and CCL9 upon treatment with Ocoxin. Moreover, RNASeq showed that Ocoxin downregulated the cell cycle and proliferation-related genes. In vivo, Ocoxin reduced the number of lung metastasis of YUMM-1.7 melanoma cells. Therefore, Ocoxin arises as a good candidate for clinical trials analyzing the beneficial effects in patients suffering from this cutaneous malignancy.

Hippo Signaling Pathway as a Central Mediator of Receptors Tyrosine Kinases (RTKs) in Tumorigenesis

The Hippo pathway plays a critical role in tissue and organ growth under normal physiological conditions, and its dysregulation in malignant growth has made it an attractive target for therapeutic intervention in the fight against cancer. To date, its complex signaling mechanisms have made it difficult to identify strong therapeutic candidates. Hippo signaling is largely carried out by two main activated signaling pathways involving receptor tyrosine kinases (RTKs)—the RTK/RAS/PI3K and the RTK-RAS-MAPK pathways. However, several RTKs have also been shown to regulate this pathway to engage downstream Hippo effectors and ultimately influence cell proliferation. In this text, we attempt to review the diverse RTK signaling pathways that influence Hippo signaling in the context of oncogenesis.

Cold Atmospheric Plasma Is a Potent Tool to Improve Chemotherapy in Melanoma In Vitro and In Vivo

Malignant melanoma is a devastating disease. Because of its aggressiveness, it also serves as a model tumor for investigating novel therapeutic avenues. In recent years, scientific evidence has shown that cold atmospheric plasma (CAP) might be a promising modality in cancer therapy. In this study, we aimed to evaluate the effect of CAP generated by an argon plasma jet alone or in combination with dacarbazine (DAC) on melanoma cells in vitro and in vivo. The effects of the CAP on inducing lipid peroxidation and nitric oxide production were higher in B16 melanoma cells in comparison to non-malignant L929 cells. Assays on cell growth, apoptosis, and expression of genes related to, e.g., autophagic processes, showed CAP to have a substantial impact in melanoma cells while there were only minoreffects in L929 cells. In vivo, both CAP monotherapy and combination with DAC significantly decreased tumor growth. These results suggest that CAP not only selectively induces cell death in melanoma but also holds promises in combination with chemotherapy that might lead to improved tumor control.

Salubrinal in Combination With 4E1RCat Synergistically Impairs Melanoma Development by Disrupting the Protein Synthetic Machinery

Increased protein synthesis is a key process in melanoma, which is regulated by the ALDH18A1 gene encoding pyrroline-5-carboxylate synthase (P5CS). P5CS is involved in proline biosynthesis and targeting ALDH18A1 has previously been shown to inhibit melanoma development by decreasing intracellular proline levels to increase the phosphorylation of eIF2α mediated by GCN2, which then impairs mRNA translation. Since there are no current inhibitors of P5CS, decreased eIF2α phosphorylation in melanoma was targeted using salubrinal (a specific inhibitor of eIF2α phosphatase enzymes). While salubrinal alone was ineffective, the combined use of salubrinal and 4E1RCat (a dual inhibitor of eIF4E:4E-BP1 and eIF4E:eIF4G interaction to prevent assembly of the eIF4F complex and inhibit cap-dependent translation) was found to be effective at decreasing protein synthesis, protein translation, and cell cycle progression to synergistically decrease melanoma cell viability and inhibited xenograft melanoma tumor development. The combination of these agents synergistically decreased melanoma cell viability while having minimal effect on normal cells. This is the first report demonstrating that it is possible to inhibit melanoma viability by targeting eIF2α signaling using salubrinal and 4E1RCat to disrupt assembly of the eIF4F complex.

Dual Targeting of BRAF and mTOR Signaling in Melanoma Cells with Pyridinyl Imidazole Compounds

BRAF inhibitors can delay the progression of metastatic melanoma, but resistance usually emerges, leading to relapse. Drugs simultaneously targeting two or more pathways essential for cancer growth could slow or prevent the development of resistant clones. Here, we identified pyridinyl imidazole compounds SB202190, SB203580, and SB590885 as dual inhibitors of critical proliferative pathways in human melanoma cells bearing the V600E activating mutation of BRAF kinase. We found that the drugs simultaneously disrupt the BRAF V600E-driven extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) activity and the mechanistic target of rapamycin complex 1 (mTORC1) signaling in melanoma cells. Pyridinyl imidazole compounds directly inhibit BRAF V600E kinase. Moreover, they interfere with the endolysosomal compartment, promoting the accumulation of large acidic vacuole-like vesicles and dynamic changes in mTOR signaling. A transient increase in mTORC1 activity is followed by the enrichment of the Ragulator complex protein p18/LAMTOR1 at contact sites of large vesicles and delocalization of mTOR from the lysosomes. The induced disruption of the endolysosomal pathway not only disrupts mTORC1 signaling, but also renders melanoma cells sensitive to endoplasmic reticulum (ER) stress. Our findings identify new activities of pharmacologically relevant small molecule compounds and provide a biological rationale for the development of anti-melanoma therapeutics based on the pyridinyl imidazole core.

A digital mRNA expression signature to classify challenging Spitzoid melanocytic neoplasms

Spitzoid neoplasms are a challenging group of cutaneous melanocytic proliferations. They are characterized by epithelioid and/or spindle-shaped melanocytes and classified as benign Spitz nevi (SN), atypical Spitz tumors (AST), or malignant Spitz tumors (MST). The intermediate AST category represents a diagnostically challenging group since on purely histopathological grounds, their benign or malignant character remains unpredictable. This results in uncertainties in patient treatment and prognosis. The molecular properties of Spitzoid lesions, especially their transcriptomic landscape, remain poorly understood, and genomic alterations in melanoma-associated oncogenes are typically absent. The aim of this study was to characterize their transcriptome with digital mRNA expression profiling. Formalin-fixed paraffin-embedded samples (including 27 SN, 10 AST, and 14 MST) were analyzed using the NanoString nCounter PanCancer Pathways Panel. The number of significantly differentially expressed genes in SN vs. MST, SN vs. AST, and AST vs. MST was 68, 167, and 18, respectively. Gene set enrichment analysis revealed upregulation of pathways related to epithelial-mesenchymal transition and immunomodulatory-, angiogenesis-, hormonal-, and myogenesis-associated processes in AST and MST. A molecular signature of SN vs. MST was discovered based on the top-ranked most informative genes: NRAS, NF1, BMP2, EIF2B4, IFNA17, and FZD9. The AST samples showed intermediate levels of the identified signature. This implies that the gene signature can potentially be used to distinguish high-grade from low-grade AST with a larger study cohort in the future. This combined histopathological and transcriptomic methodology is promising for prospective diagnostics of Spitzoid neoplasms and patient management in dermatological oncology.

Identification of Small Molecule Enhancers of Immunotherapy for Melanoma

Small molecule based targeted therapies for the treatment of metastatic melanoma hold promise but responses are often not durable, and tumors frequently relapse. Response to adoptive cell transfer (ACT)-based immunotherapy in melanoma patients are durable but patients develop resistance primarily due to loss of antigen expression. The combination of small molecules that sustain T cell effector function with ACT could lead to long lasting responses. Here, we have developed a novel co-culture cell-based high throughput assay system to identify compounds that could potentially synergize or enhance ACT-based immunotherapy of melanoma. A BRAF^V600E mutant melanoma cell line, SB-3123_p which is resistant to Pmel-1-directed ACT due to low gp100 expression levels was used to develop a homogenous time resolve fluorescence (HTRF), screening assay. This high throughput screening assay quantitates IFNγ released upon recognition of the SB-3123_p melanoma cells by Pmel-1 CD8⁺ T-cells. A focused collection of approximately 500 small molecules targeting a broad range of cellular mechanisms was screened, and four active compounds that increased melanoma antigen expression leading to enhanced IFNγ production were identified and their in vitro activity was validated. These four compounds may provide a basis for enhanced immune recognition and design of novel therapeutic approaches for patients with BRAF mutant melanoma resistant to ACT due to antigen downregulation.

Is single versus combination therapy problematic in the treatment of cutaneous melanoma?

Introduction: The development of immunotherapies and targeted therapies has changed the treatment approach in resectable, nonresectable, and metastatic melanoma. Because of their different pharmacological profiles, immunotherapies and/or targeted therapies have been studied in various combinations. Areas covered: We reviewed PubMed for most important clinical trials investigating efficacy and tolerability of combinatorial and single-agent approaches for the treatment of melanoma that were published up to June 2019. We discuss the most promising therapy approaches and highlight challenges of melanoma treatment. Expert opinion: Combinatorial approaches seem to be very promising in the treatment of resectable and advanced melanoma. Currently, dual immune checkpoint inhibition (ICI) with nivolumab and ipilimumab offers the best first-line treatment option for patients with BRAF-wt and -mutated, advanced melanoma. It is therapy of choice in younger patients with good ECOG performance status and poor prognostic features, whereas ICI monotherapy should be preferred in elderly patients with advanced melanoma. Benefit-risk ratio, patient's QoL and expectations, as well as treatment costs have to be considered in the choice of treatment. However, to elucidate mechanisms of resistance, biomarkers of response and to better define personalized strategies in the treatment of cutaneous melanoma, larger clinical trials comparing combined versus sequential therapies are necessary.

Deoxynivalenol Induces Inflammation in IPEC-J2 Cells by Activating P38 Mapk And Erk1/2

Fusarium-derived mycotoxin deoxynivalenol (DON) usually induces diarrhea, vomiting and gastrointestinal inflammation. We studied the cytotoxic effect of DON on porcine small intestinal epithelium using the intestinal porcine epithelial cell line IPEC-J2. We screened out differentially expressed genes (DEGs) using RNA-seq and identified 320 upregulated genes and 160 downregulated genes. The enrichment pathways of these DEGs focused on immune-related pathways. DON induced proinflammatory gene expression, including cytokines, chemokines and other inflammation-related genes. DON increased IL1A, IL6 and TNF-α release and DON activated the phosphorylation of extracellular signal-regulated kinase-1 and-2 (ERK1/2), JUN N-terminal kinase (JNK) and p38 MAPK. A p38 inhibitor attenuated DON-induced IL6, TNF-α, CXCL2, CXCL8, IL12A, IL1A, CCL20, CCL4 and IL15 production, while an ERK1/2 inhibitor had only a small inhibitory effect on IL15 and IL6. An inhibitor of p38 MAPK decreased the release of IL1A, IL6 and TNF-α and an inhibitor of ERK1/2 partly attenuated protein levels of IL6. These data demonstrate that DON induces proinflammatory factor production in IPEC-J2 cells by activating p38 and ERK1/2.

Intra- and Inter-Tumor BRAF Heterogeneity in Acral Melanoma: An Immunohistochemical Analysis

The current development of BRAF inhibitors has revolutionized the treatment of unresectable melanoma. As the potential heterogeneity of BRAF mutations in melanoma has been reported, accurate detection of BRAF mutations are important. However, the genetic heterogeneity of acral melanoma-a distinct type of melanoma with a unique genetic background-has not fully been investigated. We conducted a retrospective review of our acral melanoma patients. Of the 196 patients with acral melanoma, we retrieved 31 pairs of primary and matched metastatic melanomas. We immunostained the 31 pairs with VE1, a BRAFV600E-mutation-specific monoclonal antibody. Immunohistochemistry with VE1 showed a high degree of sensitivity and specificity for detecting BRAFV600E mutations compared with the real-time polymerase chain reaction method. A total of nine primary (29.0%) and eight metastatic (25.8%) acral melanomas were positive for VE1. In three patients (9.7%), we observed a discordance of VE1 staining between the primary and metastatic lesions. Of note, VE1 immunohistochemical staining revealed a remarkable degree of intra-tumor genetic heterogeneity in acral melanoma. Our study reveals that VE1 immunostaining is a useful ancillary method for detecting BRAFV600E mutations in acral melanoma and allows for a clear visualization of intra- and inter-tumor BRAF heterogeneity.

Prognostic value of genome-wide DNA methylation patterns in noncoding miRNAs and lncRNAs in uveal melanomas

Background: Uveal melanomas are the most common primary intraocular malignant tumors in adults, associated with a high metastasis rate and a low 5-year survival rate. It is a clinic urgency and importance to identify prognostic factors for UVMs.

Results: 55 aberrantly methylated sites of miRNAs and 47 aberrantly methylated sites of lncRNAs were observed between Alive < 2 years group and Alive > 2 years group of UVMs. Two prognostic classifiers were generated. For 13- miRNAs-CpG-classifier, the AUC were 0.958, 0.848 and 0.824 at 1 year, 2 years and 3 years, respectively. For 9- lncRNAs-CpG-classifier, the AUC were 0.943, 0.869 and 0.866 at 1 year, 2 years and 3 years, respectively.

Conclusion: The correlation between genome-wide DNA methylation patterns of miRNAs and lncRNAs and the overall survival in UVMs were identified in this study. This novel finding shed new light on developing biomarkers of prognosis for UVMs.

Methods: DNA methylation profiles of noncoding miRNAs and lncRNAs for UVMs were accessed from The Cancer Genome Atlas. Then the prognostic value was analyzed by least absolute shrinkage and selection operator method Cox regression and tested by Time-dependent Receiver Operating Characteristic curve.

C-Jun drives melanoma progression in PTEN wild type melanoma cells

Due to the critical impact of active AP-1 transcription factors in melanoma, it is important to define their target genes and to identify and ultimately inhibit oncogenic signals. Here we mapped the genome-wide occupancy of the AP-1 family member c-Jun in different melanoma cells and correlated AP-1 binding with transcriptome data to detect genes in melanoma regulated by c-Jun. Our analysis shows that c-Jun supports the malignant phenotype by deregulating genes in cancer-relevant signaling pathways, such as mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-kinase (PI3K) pathways. Moreover, we demonstrate that the importance of c-Jun depends on melanoma stage and mutation status of the tumor suppressor PTEN. Our study reveals that activation of c-Jun overrules the tumor suppressive effect of PTEN in early melanoma development. These findings help to understand the relevance of c-Jun within cancer pathways in different melanoma cell types, especially in relation to MAPK and PI3K pathways, which are commonly deregulated in melanomas. Consequently, targeting c-Jun in PTEN⁺ melanoma cells may represent a promising therapeutic strategy to inhibit survival of melanoma cells to prevent the development of a metastatic phenotype.

The Mechanism of MAPK Signal Transduction Pathway Involved with Electroacupuncture Treatment for Different Diseases

The mitogen-activated protein kinase (MAPK) signal transduction pathway plays an important role in the regulation of various diseases, such as cardiovascular and cerebrovascular diseases, and takes part in anti-inflammatory effects, analgesic effects, protection against injury, and maintenance of gastrointestinal functions. Electroacupuncture therapy is an external therapy used in traditional Chinese medicine. By adding external electrical stimulation to traditional acupuncture, the stimulus gets doubled and the therapeutic efficacy gets enhanced accordingly. It combines the benefits of both acupuncture and electrical stimulation. In recent years, some studies have explored the molecular mechanisms of MAPK signal pathways involved with electroacupuncture treatment. Based on these recent studies, this article summarizes the mechanisms of MAPK signal transduction pathways involved with electroacupuncture treatment. This adds great value to the studies of molecular mechanisms of electroacupuncture treatment and also provides an effective reference for its clinical use.

Cold atmospheric plasma and silymarin nanoemulsion synergistically inhibits human melanoma tumorigenesis via targeting HGF/c-MET downstream pathway

BACKGROUND

Recent studies claimed the important role of cold atmospheric plasma (CAP) with nanotechnology in cancer treatments. In this study, silymarin nanoemulsion (SN) was used along with air CAP as therapeutic agent to counter human melanoma.

METHODS

In this study, we examined the combined treatment of CAP and SN on G-361 human melanoma cells by evaluating cellular toxicity levels, reactive oxygen and nitrogen species (RONS) levels, DNA damage, melanoma-specific markers, apoptosis, caspases and poly ADP-ribose polymerase-1 (PARP-1) levels using flow cytometer. Dual-treatment effects on the epithelial-mesenchymal transition (EMT), Hepatocyte growth factor (HGF/c-MET) pathway, sphere formation and the reversal of EMT were also assessed using western blotting and microscopy respectively. SN and plasma-activated medium (PAM) were applied on tumor growth and body weight and melanoma-specific markers and the mesenchymal markers in the tumor xenograft nude mice model were checked.

RESULTS

Co-treatment of SN and air CAP increased the cellular toxicity in a time-dependent manner and shows maximum toxicity at 200 nM in 24 h. Intracellular RONS showed significant generation of ROS (< 3 times) and RNS (< 2.5 times) in dual-treated samples compared to control. DNA damage studies were assessed by estimating the level of γ-H2AX (1.8 times), PD-1 (> 2 times) and DNMT and showed damage in G-361 cells. Increase in Caspase 8,9,3/7 (> 1.5 times), PARP level (2.5 times) and apoptotic genes level were also observed in dual treated group and hence blocking HGF/c-MET pathway. Decrease in EMT markers (E-cadherin, YKL-40, N-cadherin, SNAI1) were seen with simultaneously decline in melanoma cells (BRAF, NAMPT) and stem cells (CD133, ABCB5) markers. In vivo results showed significant reduction in SN with PAM with reduction in tumor weight and size.

CONCLUSIONS

The use of air CAP using μ-DBD and the SN can minimize the malignancy effects of melanoma cells by describing HGF/c-MET molecular mechanism of acting on G-361 human melanoma cells and in mice xenografts, possibly leading to suitable targets for innovative anti-melanoma approaches in the future.

Longitudinal transcriptomic and genetic landscape of radiotherapy response in canine melanoma

Canine malignant melanoma (MM) is a highly aggressive tumour with a low survival rate and represents an ideal spontaneous model for the human counterpart. Considerable progress has been recently obtained, but the therapeutic success for canine melanoma is still challenging. Little is known about the mechanisms beyond pathogenesis and melanoma development, and the molecular response to radiotherapy has never been explored before. A faster and deeper understanding of cancer mutational processes and developing mechanisms are now possible through next generation sequencing technologies. In this study, we matched whole exome and transcriptome sequencing in four dogs affected by MM at diagnosis and at disease progression to identify possible genetic mechanisms associated with therapy failure. According to previous studies, a genetic similarity between canine MM and its human counterpart was observed. Several somatic mutations were functionally related to MAPK, PI3K/AKT and p53 signalling pathways, but located in genes other than BRAF, RAS and KIT. At disease progression, several mutations were related to therapy effects. Natural killer cell-mediated cytotoxicity and several immune-system-related pathways resulted activated opening a new scenario on the microenvironment in this tumour. In conclusion, this study suggests a potential role of the immune system associated to radiotherapy in canine melanoma, but a larger sample size associated with functional studies are needed.

Photodynamic Therapy in Melanoma - Where do we Stand?

BACKGROUND

Malignant melanoma is one of the most aggressive malignant tumors, with unpredictable evolution. Despite numerous therapeutic options, like chemotherapy, BRAF inhibitors and immunotherapy, advanced melanoma prognosis remains severe. Photodynamic therapy (PDT) has been successfully used as the first line or palliative therapy for the treatment of lung, esophageal, bladder, non melanoma skin and head and neck cancers. However, classical PDT has shown some drawbacks that limit its clinical application in melanoma.

OBJECTIVE

The most important challenge is to overcome melanoma resistance, due to melanosomal trapping, presence of melanin, enhanced oxidative stress defense, defects in the apoptotic pathways, immune evasion, neoangiogenesis stimulation.

METHOD

In this review we considered: (1) main signaling molecular pathways deregulated in melanoma as potential targets for personalized therapy, including PDT, (2) results of the clinical studies regarding PDT of melanoma, especially advanced metastatic stage, (3) progresses made in the design of anti-melanoma photosensitizers (4) inhibition of tumor neoangiogenesis, as well as (5) advantages of the derived therapies like photothermal therapy, sonodynamic therapy.

RESULTS

PDT represents a promising alternative palliative treatment for advanced melanoma patients, mainly due to its minimal invasive character and low side effects. Efficient melanoma PDT requires: (1) improved, tumor targeted, NIR absorbing photosensitizers, capable of inducing high amounts of different ROS inside tumor and vasculature cells, possibly allowing a theranostic approach; (2) an efficient adjuvant immune therapy.

CONCLUSION

Combination of PDT with immune stimulation might be the key to overcome the melanoma resistance and to obtain better, sustainable clinical results.

Down-regulation of FZD3 receptor suppresses growth and metastasis of human melanoma independently of canonical WNT signaling

Frizzled 3 receptor (FZD3) plays an important role in the homeostasis of the neural crest and its derivatives, which give rise to pigment-synthesizing cells, melanocytes. While the role for FZD3 in specification of the melanocytic lineage from neural crest is well established, its significance in the formation of melanoma, its associated malignancy, is less understood. In this study we identified FZD3 as a critical regulator of human melanoma tumorigenesis. Down-regulation of FZD3 abrogated growth, colony-forming potential, and invasive capacity of patient-derived melanoma cells. Xenotransplantation of tumor cells with down-regulated FZD3 levels originating from melanomas carrying the BRAF(V600) mutation uniformly suppressed their capacity for tumor and metastasis formation. FZD3 knockdown leads to the down-regulation of the core cell cycle protein components (cyclins D1, E2, B1, and CDKs 1, 2, and 4) in melanomas with a hyperactive BRAF oncogene, indicating a dominant role of this receptor during melanoma pathogenesis. Enriched pathway analysis revealed that FZD3 inhibits transcriptional networks controlled by CREB5, FOXD1, and ATF3, which suppress the activity of MAPK-mediated signaling. Thus, FZD3 establishes a positive-feedback mechanism that activates MAPK signal transduction network, critical to melanoma carcinogenesis. Importantly, high levels of FZD3 mRNA were found to be correlated with melanoma advancement to metastatic stages and limited patient survival. Changes in gene-expression patterns mediated by FZD3 activity occur in the absence of nuclear β-catenin function, thus representing an important therapeutic target for the melanoma patients whose disease progresses independent of canonical WNT signaling.

MicroRNA-23a-3p Inhibits Mucosal Melanoma Growth and Progression through Targeting Adenylate Cyclase 1 and Attenuating cAMP and MAPK Pathways

Mucosal melanoma (MM) is the second most common melanoma subtype in Asian populations. Deregulation of microRNAs (miRNAs) has been extensively investigated in various cancers, including cutaneous melanoma. However, the roles of miRNAs in MM are unclear. In this study, we carried out miRNA profiling in MM, and we investigated the clinical and biological roles of miR-23a-3p in MM.

Methods: miRNA expression in MM was profiled by miRNA microarray analysis. The expression of miR-23a-3p was quantitated by qRT-PCR in a cohort of 117 patients with MM, and its prognostic significance was evaluated. The biological effect of miR-23a-3p was demonstrated by both in vitro and in vivo studies through ectopic expression of miR-23a-3p. The target gene of miR-23a-3p and molecular pathway influenced by it was characterized using in silico target prediction tools, dual luciferase reporter assays, knockdown, and rescue experiments.

Results: Microarray and qRT-PCR results showed that the miR-23a-3p level was substantially lower in MM, and low miR-23a-3p expression was significantly associated with poor outcomes. Ectopic expression of miR-23a-3p suppressed MM cell proliferation, migration, invasion, and tumorigenicity, indicating that miR-23a-3p has a tumor-suppressive role in MM. Mechanistic investigations identified adenylate cyclase 1 (ADCY1) as a direct target of miR-23a-3p in MM, and knockdown of ADCY1 recapitulated all the phenotypic characteristics of miR-23a-3p overexpression. Targeting of ADCY1 by miR-23a-3p resulted in the suppression of cyclic adenosine monophosphate (cAMP) and mitogen-activated protein kinase (MAPK) signaling pathways.

Conclusions: Our data highlight the molecular etiology and clinical significance of miR-23a-3p in MM and reveal its major target and biological function. miR-23a-3p may represent a new prognostic biomarker or therapeutic target in MM.

Effect of ABT-888 on the apoptosis, motility and invasiveness of BRAFi-resistant melanoma cells

Melanoma is a molecularly heterogeneous disease with many genetic mutations and altered signaling pathways. Activating mutations in the BRAF oncogene are observed in approximately 50% of cutaneous melanomas and the use of BRAF inhibitor (BRAFi) compounds has been reported to improve the outcome of patients with BRAF-mutated metastatic melanoma. However, the majority of these patients develop resistance within 6-8 months following the initiation of BRAFi treatment. In this study, we examined the possible use of the poly(ADP-ribose) polymerase 1 (PARP1) inhibitor, ABT-888 (veliparib), as a novel molecule that may be successfully employed in the treatment of BRAFi-resistant melanoma cells. Sensitive and resistant to BRAFi dabrafenib A375 cells were exposed to increasing concentrations of ABT-888. Cell viability and apoptosis were assessed by MTT assay and Annexin V-FITC analysis, respectively. The cell migratory and invasive ability was investigated using the xCELLigence technology and Boyden chamber assays, respectively. ABT-888 was found to reduce cell viability and exhibited pro-apoptotic activity in melanoma cell lines, independently from the BRAF/NRAS mutation status, in a dose-dependent manner, with the maximal effect being reached in the 25-50 µM concentration range. Moreover, ABT-888 promoted apoptosis in both the sensitive and resistant A375 cells, suggesting that ABT-888 may be useful in the treatment of BRAFi-resistant subsets of melanoma cells. Finally, in accordance with the involvement of PARP1 in actin cytoskeletal machinery, we found that the cytoskeletal organization, motility and invasive capability of both the A375 and A375R cells decreased upon exposure to 5 µM ABT-888 for 24 h. On the whole, the findings of this study highlight the pivotal role of PARP1 in the migration and invasion of melanoma cells, suggesting that ABT-888 may indeed be effective, not only as a pro-apoptotic drug for use in the treatment of BRAFi-resistant melanoma cells, but also in suppressing their migratory and invasive activities.

Identification of a Novel BRAF Thr599dup Mutation in Lung Adenocarcinoma

BRAF mutations are known as oncogenic drivers of non-small cell lung cancer (NSCLC). BRAF inhibition has demonstrated anti-tumor activity in patients with BRAF V600E mutant NSCLC. Further molecular screening for novel BRAF thr599dup mutation is warranted. The novel BRAF Thr599dup gene mutation, for which the repeat amino acid-tyrosine is inserted between the 599th amino acid and the 600th amino acid in exon 15 of BRAF, was identified by next-generation sequencing (NGS) during routine clinical care in a lung carcinoma sample from an Asian never-smoker. Other putative driver alterations including EGFR, ALK were not found in that patient. BRAF Thr599dup gene mutation analysis was consistent with BRAF v600E gene mutation. Here we report a novel BRAF gene mutation with molecular characteristics consistent with those in BRAF-driven NSCLC. Our case expands the scope of BRAF gene mutations and provides broader molecular profiling for optimizing therapeutic options for patients with NSCLC. The new BRAF gene mutation has important clinical meaning for cancer patients.