Targeting MAPK pathway in melanoma therapy

Immune checkpoint inhibitors for glioblastoma: emerging science, clinical advances, and future directions

Glioblastoma (GBM), the most common and aggressive primary central nervous system (CNS) tumor in adults, continues to have a dismal prognosis. Across hundreds of clinical trials, few novel approaches have translated to clinical practice while survival has improved by only a few months over the past three decades. Randomized controlled trials of immune checkpoint inhibitors (ICIs), which have seen impressive success for advanced or metastatic extracranial solid tumors, have so far failed to demonstrate a clinical benefit for patients with GBM. This has been secondary to GBM heterogeneity, the unique immunosuppressive CNS microenvironment, immune-evasive strategies by cancer cells, and the rapid evolution of tumor on therapy. This review aims to summarize findings from major clinical trials of ICIs for GBM, review historic failures, and describe currently promising avenues of investigation. We explore the biological mechanisms driving ICI responses, focusing on the role of the tumor microenvironment, immune evasion, and molecular biomarkers. Beyond conventional monotherapy approaches targeting PD-1, PD-L1, CTLA-4, we describe emerging approaches for GBM, such as dual-agent ICIs, and combination of ICIs with oncolytic virotherapy, antigenic peptide vaccines, chimeric antigenic receptor (CAR) T-cell therapy, along with nanoparticle-based delivery systems to enhance ICI efficacy. We highlight potential strategies for improving patient selection and treatment personalization, along with real-time, longitudinal monitoring of therapeutic responses through advanced imaging and liquid biopsy techniques. Integrated radiomics, tissue, and plasma-based analyses, may potentially uncover immunotherapeutic response signatures, enabling early, adaptive therapeutic adjustments. By specifically targeting current therapeutic challenges, outcomes for GBM patients may potentially be improved.

AI-driven eyelid tumor classification in ocular oncology using proteomic data

Eyelid tumors pose diagnostic challenges due to their diverse pathological types and limited biopsy materials. This study aimed to develop an artificial intelligence (AI) diagnostic system for accurate classification of eyelid tumors. Utilizing mass spectrometry-based proteomics, we analyzed proteomic data from eight tissue types and identified eighteen novel biomarkers based on 233 formalin-fixed, paraffin-embedded (FFPE) samples from 150 patients. The 18-protein model, validated by an independent cohort (99 samples from 60 patients), exhibited high accuracy (84.8%), precision (86.2%), and recall (84.8%) in multi-class classification. The model demonstrated distinct clustering of different lesion types, as visualized through UMAP plots. Receiver operator characteristic (ROC) curve analysis revealed strong predictive ability with area under the curve (AUC) values ranging from 0.80 to 1.00. This AI-based diagnostic system holds promise for improving the efficiency and precision of eyelid tumor diagnosis, addressing the limitations of traditional pathological methods.

Pharmacological targeting of casein kinase 1δ suppresses oncogenic NRAS-driven melanoma

Activating mutations in NRAS account for 15-20% of melanoma, yet effective anti-NRAS therapies are still lacking. In this study, we unveil the casein kinase 1δ (CK1δ) as an uncharacterized regulator of oncogenic NRAS mutations, specifically Q61R and Q61K, which are the most prevalent NRAS mutations in melanoma. The genetic ablation or pharmacological inhibition of CK1δ markedly destabilizes NRAS mutants and suppresses their oncogenic functions. Moreover, we identify USP46 as a bona fide deubiquitinase of NRAS mutants. Mechanistically, CK1δ directly phosphorylates USP46 and activates its deubiquitinase activity towards NRAS mutants, thus promoting oncogenic NRAS-driven melanocyte malignant transformation and melanoma progression in vitro and in vivo. Our findings underscore the significance of the CK1δ-USP46 axis in stabilizing oncogenic NRAS mutants and provide preclinical evidence that targeting this axis holds promise as a therapeutic strategy for human melanoma harboring NRAS mutations.

Comparative Analysis of Olive-Derived Phenolic Compounds' Pro-Melanogenesis Effects on B16F10 Cells and Epidermal Human Melanocytes

Olive leaf contains plenty of phenolic compounds, among which oleuropein (OP) is the main component and belongs to the group of secoiridoids. Additionally, phenolic compounds such as oleocanthal (OL) and oleacein (OC), which share a structural similarity with OP and two aldehyde groups, are also present in olive leaves. These compounds have been studied for several health benefits, such as anti-cancer and antioxidant effects. However, their impact on the skin remains unknown. Therefore, this study aims to compare the effects of these three compounds on melanogenesis using B16F10 cells and human epidermal cells. Thousands of gene expressions were measured by global gene expression profiling with B16F10 cells. We found that glutaraldehyde compounds derived from olive leaves have a potential effect on the activation of the melanogenesis pathway and inducing differentiation in B16F10 cells. Accordingly, the pro-melanogenesis effect was investigated by means of melanin quantification, mRNA, and protein expression using human epidermal melanocytes (HEM). This study suggests that secoiridoid and its derivates have an impact on skin protection by promoting melanin production in both human and mouse cell lines.

Anti-inflammatory potential of ulvan

Green seaweeds are a widespread group of marine macroalgae that could be regarded as biorenewable source of valuable compounds, in particular sulfated polysaccharides like ulvans with interesting biological properties. Among them, anti-inflammatory activity represents an interesting target, since ulvans could potentially avoid side effects of conventional therapies. However, a great variability in ulvan content, composition, structure and properties occurs depending on seaweed specie and growth and processing conditions. All these aspects should be carefully considered in order to have reproducible and well characterized products. This review presents some concise ideas on ulvan composition and general concepts on inflammation mechanisms. Then, the main focus is on the importance of adequate selection of extraction, depolymerization and purification technologies followed by an updated survey on anti-inflammatory properties of ulvans through modulation of different signaling pathways. The potential application in a number of diseases, with special emphasis on inflammaging, gut microbiota dysbiosis, wound repair, and metabolic diseases is also discussed. This multidisciplinary overview tries to present the potential of ulvans considering not only mechanistic, but also processing and applications aspects, trusting that it can aid in the development and application of this widely available and renewable resource as an efficient and versatile anti-inflammatory agent.

Ocular Inflammatory Complications of Treatment for Metastatic Melanoma

PURPOSE

To characterize various ocular inflammatory complications arising from metastatic cutaneous melanoma therapies and their management.

METHODS

Retrospective case series of patients who were referred to a tertiary uveitis practice for ophthalmic exam All patients received targeted metastatic cutaneous melanoma treatment, including BRAF/MEK inhibitors and various immunotherapies.

RESULTS

109 patients were identified, with 43 (39.4%) having 65 definitive instances of OIAE. Sixteen different OIAE were identified. Ipilimumab monotherapy and ipilimumab/nivolumab combination therapy were most commonly associated. Anterior uveitis was the most common OIAE (18/65, 27.7%). Thirty patients (69.8%) were managed with observation or topical steroid therapy. Only 4 patients required further therapies for OIAE, with one patient not attaining resolution.

CONCLUSIONS AND RELEVANCE

While a broad range of OIAE was identified, most were not vision-threatening and did not require discontinuation of the associated therapy.

PARP Inhibitors Effectively Reduce MAPK Inhibitor Resistant Melanoma Cell Growth and Synergize with MAPK Inhibitors through a Synthetic Lethal Interaction In Vitro and In Vivo

The efficacy of targeting the MAPK signaling pathway in patients with melanoma is limited by the rapid development of resistance mechanisms that result in disease relapse. In this article, we focus on targeting the DNA repair pathway as an antimelanoma therapy, especially in MAPK inhibitor resistant melanoma cells using PARP inhibitors. We found that MAPK inhibitor resistant melanoma cells are particularly sensitive to PARP inhibitor treatment due to a lower basal expression of the DNA damage sensor ataxia-telangiectasia mutated (ATM). As a consequence, MAPK inhibitor resistant melanoma cells have decreased homologous recombination repair activity leading to a reduced repair of double-strand breaks caused by the PARP inhibitors. We validated the clinical relevance of our findings by ATM expression analysis in biopsies from patients with melanoma before and after development of resistance to MAPK inhibitors. Furthermore, we show that inhibition of the MAPK pathway induces a homologous recombination repair deficient phenotype in melanoma cells irrespective of their MAPK inhibitor sensitivity status. MAPK inhibition results in a synthetic lethal interaction of a combinatorial treatment with PARP inhibitors, which significantly reduces melanoma cell growth in vitro and in vivo. In conclusion, this study shows that PARP inhibitor treatment is a valuable therapy option for patients with melanoma, either as a single treatment or as a combination with MAPK inhibitors depending on ATM expression.

Significance

We show that MAPK inhibitor resistant melanoma cells exhibit low ATM expression increasing their sensitivity toward PARP inhibitors and that a combination of MAPK/PARP inhibitors act synthetically lethal in melanoma cells. Our study shows that PARP inhibitor treatment is a valuable therapy option for patients with melanoma, either as a single treatment or as a combination with MAPK inhibitors depending on ATM expression, which could serve as a novel biomarker for treatment response.

2-Methoxyestradiol-3,17-O,O-bis-sulfamate (STX140) Inhibits Proliferation and Invasion via Senescence Pathway Induction in Human BRAFi-Resistant Melanoma Cells

The endogenous estradiol derivative 2-Methoxyestradiol (2-ME) has shown good and wide anticancer activity but suffers from poor oral bioavailability and extensive metabolic conjugation. However, its sulfamoylated derivative, 2-methoxyestradiol-3,17-O,O-bis-sulfamate (STX140), has superior potential as a therapeutic agent, acts by disrupting microtubule polymerization, leading to cell cycle arrest and apoptosis in cancer cells and possesses much better pharmaceutical properties. This study investigated the antiproliferative and anti-invasive activities of STX140 in both SKMEL-28 naïve melanoma (SKMEL28-P) cells and resistant melanoma cells (SKMEL-28R). STX140 inhibited cell proliferation in the nanomolar range while having a less pronounced effect on human melanocytes. Additionally, STX140 induced cell cycle arrest in the G2/M phase and sub-G1, reduced migration, and clonogenic potential in monolayer models, and inhibited invasion in a 3D human skin model with melanoma cells. Furthermore, STX140 induced senescence features in melanoma and activated the senescence machinery by upregulating the expression of senescence genes and proteins related to senescence signaling. These findings suggest that STX140 may hold potential as a therapeutic agent for melanoma treatment.

New small molecules in dermatology: for the autoimmunity, inflammation and beyond

OBJECTIVE AND DESIGN

The discovery of new inflammatory pathways and the mechanism of action of inflammatory, autoimmune, genetic, and neoplastic diseases led to the development of immunologically driven drugs. We aimed to perform a narrative review regarding the rising of a new class of drugs capable of blocking important and specific intracellular signals in the maintenance of these pathologies: the small molecules.

MATERIALS/METHODS

A total of 114 scientific papers were enrolled in this narrative review.

RESULTS

We describe in detail the families of protein kinases-Janus Kinase (JAK), Src kinase, Syk tyrosine kinase, Mitogen-Activated Protein Kinase (MAPK), and Bruton Tyrosine Kinase (BTK)-their physiologic function and new drugs that block these pathways of intracellular signaling. We also detail the involved cytokines and the main metabolic and clinical implications of these new medications in the field of dermatology.

CONCLUSIONS

Despite having lower specificity compared to specific immunobiological therapies, these new drugs are effective in a wide variety of dermatological diseases, especially diseases that had few therapeutic options, such as psoriasis, psoriatic arthritis, atopic dermatitis, alopecia areata, and vitiligo.

Signaling Switching from Hedgehog-GLI to MAPK Signaling Potentially Serves as a Compensatory Mechanism in Melanoma Cell Lines Resistant to GANT-61

Background: Melanoma represents the deadliest skin cancer due to its cell plasticity which results in high metastatic potential and chemoresistance. Melanomas frequently develop resistance to targeted therapy; therefore, new combination therapy strategies are required. Non-canonical signaling interactions between HH-GLI and RAS/RAF/ERK signaling were identified as one of the drivers of melanoma pathogenesis. Therefore, we decided to investigate the importance of these non-canonical interactions in chemoresistance, and examine the potential for HH-GLI and RAS/RAF/ERK combined therapy. Methods: We established two melanoma cell lines resistant to the GLI inhibitor, GANT-61, and characterized their response to other HH-GLI and RAS/RAF/ERK inhibitors. Results: We successfully established two melanoma cell lines resistant to GANT-61. Both cell lines showed HH-GLI signaling downregulation and increased invasive cell properties like migration potential, colony forming capacity, and EMT. However, they differed in MAPK signaling activity, cell cycle regulation, and primary cilia formation, suggesting different potential mechanisms responsible for resistance occurrence. Conclusions: Our study provides the first ever insights into cell lines resistant to GANT-61 and shows potential mechanisms connected to HH-GLI and MAPK signaling which may represent new hot spots for noncanonical signaling interactions.

Consensus Clustering and Survival-Related Genes of Cuproptosis in Cutaneous Melanoma

As a highly malignant tumor, the morbidity and mortality of cutaneous melanoma (CM) are increasing year by year. A novel type of cell death connected to mitochondrial metabolism is called cuproptosis. Cuproptosis regulates tumor biological behavior. Thus, genes controlling cuproptosis could be a promising candidate bioindicator for cancer therapy. Datasets of CM patients were obtained from the public database that includes clinical information and RNA-seq data. We divided CM patients into three different subgroups by unsupervised clustering method and explored the differences in functional pathways among the three subgroups by GSVA to prove the possible potential mechanism of copper death-related genes in the formation and development of CM. Secondly, we used differential analysis and Cox regression analysis to find the differential genes related to prognosis, constructed the CRG score, found the critical score for dividing high and low CRG score groups, and then analyzed the prognosis and immune infiltration of high and low CRG score groups. The results show a great correlation between OS and CRG scores. Compared with patients with high CRG scores, patients with low CRG scores have a significantly higher survival rate. In a word, copper sagging plays a certain role in the progress of CM.

Patient-specific identification of genome-wide DNA-methylation differences between intracranial and extracranial melanoma metastases

Melanomas frequently metastasize to distant organs and especially intracranial metastases still represent a major clinical challenge. Epigenetic reprogramming of intracranial metastases is thought to be involved in therapy failure, but so far only little is known about patient-specific DNA-methylation differences between intra- and extracranial melanoma metastases. Hierarchical clustering of the methylomes of 24 patient-matched intra- and extracranial melanoma metastases pairs revealed that intra- and extracranial metastases of individual patients were more similar to each other than to metastases in the same tissue from other patients. Therefore, a personalized analysis of each metastases pair was done by a Hidden Markov Model to classify methylation levels of individual CpGs as decreased, unchanged or increased in the intra- compared to the extracranial metastasis. The predicted DNA-methylation alterations were highly patient-specific differing in the number and methylation states of altered CpGs. Nevertheless, four important general observations were made: (i) intracranial metastases of most patients mainly showed a reduction of DNA-methylation, (ii) cytokine signaling was most frequently affected by differential methylation in individual metastases pairs, but also MAPK, PI3K/Akt and ECM signaling were often altered, (iii) frequently affected genes were mainly involved in signaling, growth, adhesion or apoptosis, and (iv) an enrichment of functional terms related to channel and transporter activities supports previous findings for a brain-like phenotype. In addition, the derived set of 17 signaling pathway genes that distinguished intra- from extracranial metastases in more than 50% of patients included well-known oncogenes (e.g. PRKCA, DUSP6, BMP4) and several other genes known from neuronal disorders (e.g. EIF4B, SGK1, CACNG8). Moreover, associations of gene body methylation alterations with corresponding gene expression changes revealed that especially the three signaling pathway genes JAK3, MECOM, and TNXB differ strongly in their expression between patient-matched intra- and extracranial metastases. Our analysis contributes to an in-depth characterization of DNA-methylation differences between patient-matched intra- and extracranial melanoma metastases and may provide a basis for future experimental studies to identify targets for new therapeutic approaches.

Genomics and Epigenomics in the Molecular Biology of Melanoma-A Prerequisite for Biomarkers Studies

Melanoma is a common and aggressive tumor originating from melanocytes. The increasing incidence of cutaneous melanoma in recent last decades highlights the need for predictive biomarkers studies. Melanoma development is a complex process, involving the interplay of genetic, epigenetic, and environmental factors. Genetic aberrations include BRAF, NRAS, NF1, MAP2K1/MAP2K2, KIT, GNAQ, GNA11, CDKN2A, TERT mutations, and translocations of kinases. Epigenetic alterations involve microRNAs, non-coding RNAs, histones modifications, and abnormal DNA methylations. Genetic aberrations and epigenetic marks are important as biomarkers for the diagnosis, prognosis, and prediction of disease recurrence, and for therapeutic targets. This review summarizes our current knowledge of the genomic and epigenetic changes in melanoma and discusses the latest scientific information.

Carotenoids from Marine Microalgae as Antimelanoma Agents

Melanoma cells are highly invasive and metastatic tumor cells and commonly express molecular alterations that contribute to multidrug resistance (e.g., BRAF^V600E mutation). Conventional treatment is not effective in a long term, requiring an exhaustive search for new alternatives. Recently, carotenoids from microalgae have been investigated as adjuvant in antimelanoma therapy due to their safety and acceptable clinical tolerability. Many of them are currently used as food supplements. In this review, we have compiled several studies that show microalgal carotenoids inhibit cell proliferation, cell migration and invasion, as well as induced cell cycle arrest and apoptosis in various melanoma cell lines. MAPK and NF-ĸB pathway, MMP and apoptotic factors are frequently affected after exposure to microalgal carotenoids. Fucoxanthin, astaxanthin and zeaxanthin are the main carotenoids investigated, in both in vitro and in vivo experimental models. Preclinical data indicate these compounds exhibit direct antimelanoma effect but are also capable of restoring melanoma cells sensitivity to conventional chemotherapy (e.g., vemurafenib and dacarbazine).

Co-expression of TNF receptors 1 and 2 on melanomas facilitates soluble TNF-induced resistance to MAPK pathway inhibitors

BACKGROUND

The effectiveness of MAPK pathway inhibitors (MAPKi) used to treat patients with BRAF-mutant melanoma is limited by a range of resistance mechanisms, including soluble TNF (solTNF)-mediated NF-kB signaling. solTNF preferentially signals through type-1 TNF receptor (TNFR1), however, it can also bind to TNFR2, a receptor that is primarily expressed on leukocytes. Here, we investigate the TNFR2 expression pattern on human BRAFV600E+ melanomas and its role in solTNF-driven resistance reprogramming to MAPKi.

METHODS

Flow cytometry was used to test TNFR1, TNFR2 and CD271 expression on, as well as NF-kB phosphorylation in human BRAF-mutant melanoma. The ability of melanoma cell lines to acquire MAPKi resistance in response to recombinant or macrophage-derived TNF was evaluated using the MTT cytotoxicity assay. Gene editing was implemented to knock out or knock in TNF receptors in melanoma cell lines. Knockout and knock-in cell line variants were employed to assess the intrinsic roles of these receptors in TNF-induced resistance to MAPKi. Multicolor immunofluorescence microscopy was utilized to test TNFR2 expression by melanoma in patients receiving MAPKi therapy.

RESULTS

TNFR1 and TNFR2 are co-expressed at various levels on 4/7 BRAFV600E+ melanoma cell lines evaluated in this study. In vitro treatments with solTNF induce MAPKi resistance solely in TNFR2-expressing BRAFV600E+ melanoma cell lines. TNFR1 and TNFR2 knockout and knock-in studies indicate that solTNF-mediated MAPKi resistance in BRAFV600E+ melanomas is predicated on TNFR1 and TNFR2 co-expression, where TNFR1 is the central mediator of NF-kB signaling, while TNFR2 plays an auxiliary role. solTNF-mediated effects are transient and can be abrogated with biologics. Evaluation of patient specimens indicates that TNFR2 is expressed on 50% of primary BRAFV600E+ melanoma cells and that MAPKi therapy may lead to the enrichment of TNFR2-expressing tumor cells.

CONCLUSIONS

Our data suggest that TNFR2 is essential to solTNF-induced MAPKi resistance and a possible biomarker to identify melanoma patients that can benefit from solTNF-targeting therapies.

Evolution of Molecular Targeted Cancer Therapy: Mechanisms of Drug Resistance and Novel Opportunities Identified by CRISPR-Cas9 Screening

Molecular targeted therapy has revolutionized the landscape of cancer treatment due to better therapeutic responses and less systemic toxicity. However, therapeutic resistance is a major challenge in clinical settings that hinders continuous clinical benefits for cancer patients. In this regard, unraveling the mechanisms of drug resistance may identify new druggable genetic alterations for molecularly targeted therapies, thus contributing to improved therapeutic efficacies. The recent rapid development of novel methodologies including CRISPR-Cas9 screening technology and patient-derived models provides powerful tools to dissect the underlying mechanisms of resistance to targeted cancer therapies. In this review, we updated therapeutic targets undergoing preclinical and clinical evaluation for various cancer types. More importantly, we provided comprehensive elaboration of high throughput CRISPR-Cas9 screening in deciphering potential mechanisms of unresponsiveness to molecularly targeted therapies, which will shed light on the discovery of novel opportunities for designing next-generation anti-cancer drugs.

Inhibitors of HSP90 in melanoma

HSP90 (heat shock protein 90) is an ATP-dependent molecular chaperone involved in a proper folding and maturation of hundreds of proteins. HSP90 is abundantly expressed in cancer, including melanoma. HSP90 client proteins are the key oncoproteins of several signaling pathways controlling melanoma development, progression and response to therapy. A number of natural and synthetic compounds of different chemical structures and binding sites within HSP90 have been identified as selective HSP90 inhibitors. The majority of HSP90-targeting agents affect N-terminal ATPase activity of HSP90. In contrast to N-terminal inhibitors, agents interacting with the middle and C-terminal domains of HSP90 do not induce HSP70-dependent cytoprotective response. Several inhibitors of HSP90 were tested against melanoma in pre-clinical studies and clinical trials, providing evidence that these agents can be considered either as single or complementary therapeutic strategy. This review summarizes current knowledge on the role of HSP90 protein in cancer with focus on melanoma, and provides an overview of structurally different HSP90 inhibitors that are considered as potential therapeutics for melanoma treatment.

Small molecules as theranostic agents in cancer immunology

With further research into the molecular mechanisms and roles linking immune suppression and restraint of (pre)malignancies, immunotherapies have revolutionized clinical strategies in the treatment of cancer. However, nearly 70% of patients who received immune checkpoint therapeutics showed no response. Complementary and/or synergistic effects may occur when extracellular checkpoint antibody blockades combine with small molecules targeting intracellular signal pathways up/downstream of immune checkpoints or regulating the innate and adaptive immune response. After radiolabeling with radionuclides, small molecules can also be used for estimating treatment efficacy of immune checkpoint blockades. This review not only highlights some significant intracellular pathways and immune-related targets such as the kynurenine pathway, purinergic signaling, the kinase signaling axis, chemokines, etc., but also summarizes some attractive and potentially immunosuppression-related small molecule agents, which may be synergistic with extracellular immune checkpoint blockade. In addition, opportunities for small molecule-based theranostics in cancer immunology will be discussed.

Stem Cell-Derived Models of Neural Crest Are Essential to Understand Melanoma Progression and Therapy Resistance

During development, neural crest (NC) cells are early precursors of several lineages including melanocytes. Along their differentiation from multipotent cells to mature melanocytes, NC cells will go through successive steps which require either proliferative or motile capacities. For example, they will undergo Epithelial to Mesenchymal Transition (EMT) in order the separate from the neural tube and migrate to their final location in the epidermis (Larribere and Utikal, 2013; Skrypek et al., 2017). The differentiated melanocytes are the cells of origin of melanoma tumors which progress through several stages such as radial growth phase, vertical growth phase, metastasis formation, and often resistance to current therapies. Interestingly, depending on the stage of the disease, melanoma tumor cells share phenotypes with NC cells (proliferative, motile, EMT). These phenotypes are tightly controlled by specific signaling pathways and transcription factors (TFs) which tend to be reactivated during the onset of melanoma. In this review, we summarize first the main TFs which control these common phenotypes. Then, we focus on the existing strategies used to generate human NCs. Finally we discuss how identification and regulation of NC-associated genes provide an additional approach to improving current melanoma targeted therapies.

HJC0152, a novel STAT3 inhibitor with promising anti-tumor effect in gastric cancer

Background

Aberrant activation of the signal transducer and activator of transcription 3 (STAT3) is frequently seen in patients with gastric cancer (GC), and is generally associated with worse prognosis. HJC0152, a novel STAT3 inhibitor, has shown significant anti-tumor effects in several cancers, although its role in GC remains to be clarified.

Methods

The effect of HJC0152 on STAT3 signaling pathway and the biological behaviors of GC cells were evaluated through in vitro and/or in vivo experiments. Meanwhile, RNA sequence analysis was used to further explore its potential anti-tumor mechanisms.

Results

HJC0152 inhibited the expression of activated STAT3 and its downstream target genes (c-Myc and clyclinD1) in GC cells, and restrained tumor growth in vivo. HJC0152 treatment induced apoptosis in the STAT3 hyper-activated AGS and MKN45 cell lines, along with down-regulation of survivin and Mcl1, and up-regulation of cleaved-poly(ADP-ribose) polymerase. Moreover, HJC0152 markedly inhibited migration and invasion of these cells. Finally, RNA sequence analysis and protein expression analyses showed that in addition to STAT3 suppression, HJC0152 also exerts its anti-tumor effects at least partly via the mitogen-activated protein kinases pathway.

Conclusion

Our findings highlight that HJC0152 is a promising therapeutic agent for GC.

Targeted Therapy-Resistant Melanoma Cells Acquire Transcriptomic Similarities with Human Melanoblasts

The mechanisms of adaptive and acquired drug resistance in tumors are not completely understood. So far, gene amplifications or mutations, leading to the reactivation of the MAPK or PI3K pathways have been described. In this study, we used two different methods to generate human melanoblasts: (1) via differentiation from induced pluripotent stem cells (iPSCs) and (2) via dedifferentiation from melanocytes. The melanoblast transcriptomes were then compared to the transcriptome of MAPK inhibitor-resistant melanoma cells. We observed that the expression of genes associated with cell cycle control, DNA damage control, metabolism, and cancer was altered in both melanoblast populations and in both adaptive and acquired resistant melanoma samples, compared to drug-sensitive samples. However, genes involved in antigen presentation and cellular movement were only regulated in the melanoblast populations and in the acquired resistant melanoma samples, compared to the drug-sensitive samples. Moreover, melanocyte-derived melanoblasts and adaptive resistant melanoma samples were characterized by different expression levels of certain transcription factors or genes involved in the CDK5 pathway. In conclusion, we show here that in vitro models of human melanoblasts are very important tools to comprehend the expression profiles of drug-resistant melanoma.

Treating malignant melanoma when a rare BRAF V600M mutation is present: case report and literature review

Recent years have brought major advances in the treatment of malignant melanoma. One such an advance is the treatment with BRAF tyrosine-kinase inhibitors in metastatic malignant melanomas that harbor mutations in the BRAF gene. The trials that have been performed in this setting have demonstrated superior response rates and increased overall survival, however, they mostly included patients with melanomas carrying the more common V600E and V600K mutations, not being able to assess the benefit of these treatments in situations where more rare mutations of the BRAF gene are present. We present the evolution of a patient with malignant melanoma with a rare V600M mutation in the BRAF gene, that was eventually treated with vemurafenib. Also we present a brief review of the major phase III trials that showed benefit with tyrosine-kinase inhibitors in BRAF mutated melanoma, with respect to the BRAF mutations included.

The deubiquitinase USP21 stabilizes MEK2 to promote tumor growth

Deubiquitinases (DUBs) play essential roles in normal cell proliferation and tumor growth. However, the molecular mechanisms of DUBs on hepatocellular carcinoma (HCC) remains largely unknown. In this study, based on analysis of several HCC datasets, we found that the USP21 gene, which encodes a member of the ubiquitin-specific protease family, is highly amplified and overexpressed in HCCs, with the extent of this up-regulation significantly correlating with poor clinical outcomes. Inhibition of USP21 in HCC cell lines decreased cell proliferation, anchorage-independent growth, cell cycle progression, and in vivo tumor growth. Conversely, ectopic expression of USP21 transformed the normal human hepatocyte line HL-7702 and increased the tumorigenicity of the HCC cell line MHCC97L. Mechanistically, USP21 stabilized MEK2 by decreasing its polyubiquitination at Lys48, thereby activating the ERK signaling pathway. Importantly, MEK2 partially mediated the optimal expression of USP21-mediated oncogenic phenotypes. These findings indicate that USP21-mediated deubiquitination and stabilization of MEK2 play a critical role in HCC development.

Systems biology analysis of mitogen activated protein kinase inhibitor resistance in malignant melanoma

BACKGROUND

Kinase inhibition in the mitogen activated protein kinase (MAPK) pathway is a standard therapy for cancer patients with activating BRAF mutations. However, the anti-tumorigenic effect and clinical benefit are only transient, and tumors are prone to treatment resistance and relapse. To elucidate mechanistic insights into drug resistance, we have established an in vitro cellular model of MAPK inhibitor resistance in malignant melanoma.

METHODS

The cellular model evolved in response to clinical dosage of the BRAF inhibitor, vemurafenib, PLX4032. We conducted transcriptomic expression profiling using RNA-Seq and RT-qPCR arrays. Pathways of melanogenesis, MAPK signaling, cell cycle, and metabolism were significantly enriched among the set of differentially expressed genes of vemurafenib-resistant cells vs control. The underlying mechanism of treatment resistance and pathway rewiring was uncovered to be based on non-genomic adaptation and validated in two distinct melanoma models, SK-MEL-28 and A375. Both cell lines have activating BRAF mutations and display metastatic potential.

RESULTS

Downregulation of dual specific phosphatases, tumor suppressors, and negative MAPK regulators reengages mitogenic signaling. Upregulation of growth factors, cytokines, and cognate receptors triggers signaling pathways circumventing BRAF blockage. Further, changes in amino acid and one-carbon metabolism support cellular proliferation despite MAPK inhibitor treatment. In addition, treatment-resistant cells upregulate pigmentation and melanogenesis, pathways which partially overlap with MAPK signaling. Upstream regulator analysis discovered significant perturbation in oncogenic forkhead box and hypoxia inducible factor family transcription factors.

CONCLUSIONS

The established cellular models offer mechanistic insight into cellular changes and therapeutic targets under inhibitor resistance in malignant melanoma. At a systems biology level, the MAPK pathway undergoes major rewiring while acquiring inhibitor resistance. The outcome of this transcriptional plasticity is selection for a set of transcriptional master regulators, which circumvent upstream targeted kinases and provide alternative routes of mitogenic activation. A fine-woven network of redundant signals maintains similar effector genes allowing for tumor cell survival and malignant progression in therapy-resistant cancer.

Pharmacology of Pimasertib, A Selective MEK1/2 Inhibitor

Pimasertib belongs to the growing family of mitogen activated protein kinase (MEK1/2) inhibitors undergoing clinical development for various cancer indications. Since the MEK inhibition in several cell signalling transduction cascades within tumours was considered therapeutically beneficial, number of clinical investigations of pimasertib have been reported. Despite being orally bioavailable in cancer patients, pimasertib undergoes faster clearance with a short elimination half-life. In addition, due to occurrence of toxicity, the development of pimasertib appears to be stalled. Case studies are provided on the possible utilization of pimasertib in combination therapies with other approved drugs. Based on the review, it appeared that there was the need to identify the optimal dose and the dosing regimen of pimasertib to provide a balance between safety and efficacy when combined with approved therapies.

CPI-17 drives oncogenic Ras signaling in human melanomas via Ezrin-Radixin-Moesin family proteins

Hyperactive Ras signaling has strong oncogenic effects causing several different forms of cancer. Hyperactivity is frequently induced by mutations within Ras itself, which account for up to 30% of all human cancers. In addition, hyperactive Ras signaling can also be triggered independent of Ras by either mutation or by misexpression of various upstream regulators and immediate downstream effectors. We have previously reported that C-kinase potentiated protein phosphatase-1 inhibitor of 17 kDa (CPI-17) can drive Ras activity and promote tumorigenic transformation by inhibition of the tumor suppressor Merlin. We now describe an additional element of this oncogenic mechanism in the form of the ezrin-radixin-moesin (ERM) protein family, which exhibits opposing roles in Ras activity control. Thus, CPI-17 drives Ras activity and tumorigenesis in a two-fold way; inactivation of the tumor suppressor merlin and activation of the growth promoting ERM family. The in vivo significance of this oncogenic switch is highlighted by demonstrating CPI-17's involvement in human melanoma pathogenesis.

Site-specific polyubiquitination differentially regulates parathyroid hormone receptor-initiated MAPK signaling and cell proliferation

G protein-coupled receptor (GPCR) signaling and trafficking are essential for cellular function and regulated by phosphorylation, β-arrestin, and ubiquitination. The GPCR parathyroid hormone receptor (PTHR) exhibits time-dependent reversible ubiquitination. The exact ubiquitination sites in PTHR are unknown, but they extend upstream of its intracellular tail. Here, using tandem MS, we identified Lys³⁸⁸ in the third loop and Lys⁴⁸⁴ in the C-terminal tail as primary ubiquitination sites in PTHR. We found that PTHR ubiquitination requires β-arrestin and does not display a preference for β-arrestin1 or -2. PTH stimulated PTHR phosphorylation at Thr³⁸⁷/Thr³⁹² and within the Ser⁴⁸⁹-Ser⁴⁹³ region. Such phosphorylation events may recruit β-arrestin, and we observed that chemically or genetically blocking PTHR phosphorylation inhibits its ubiquitination. Specifically, Ala replacement at Thr³⁸⁷/Thr³⁹² suppressed β-arrestin binding and inhibited PTHR ubiquitination, suggesting that PTHR phosphorylation and ubiquitination are interdependent. Of note, Lys-deficient PTHR mutants promoted normal cAMP formation, but exhibited differential mitogen-activated protein kinase (MAPK) signaling. Lys-deficient PTHR triggered early onset and delayed ERK1/2 signaling compared with wildtype PTHR. Moreover, ubiquitination of Lys³⁸⁸ and Lys⁴⁸⁴ in wildtype PTHR strongly decreased p38 signaling, whereas Lys-deficient PTHR retained signaling comparable to unstimulated wildtype PTHR. Lys-deficient, ubiquitination-refractory PTHR reduced cell proliferation and increased apoptosis. However, elimination of all 11 Lys residues in PTHR did not affect its internalization and recycling. These results pinpoint the ubiquitinated Lys residues in PTHR controlling MAPK signaling and cell proliferation and survival. Our findings suggest new opportunities for targeting PTHR ubiquitination to regulate MAPK signaling or manage PTHR-related disorders.

Overview of metastatic disease of the central nervous system

In 2016, the American Society of Clinical Oncology reported that 1.7 million Americans were diagnosed with cancer; this number will rise to 2.3 million in the United States and 22 million worldwide in 2030. This rising need is being met by an explosion of new cancer therapies, including: immune checkpoint inhibitors, T-cell therapies, tumor vaccines, antiangiogenic therapies, and various targeted therapies. This armamentarium of targeted therapies has led to better systemic control of disease and longer patient overall survival (OS). The incidence of metastatic disease to the central nervous system (CNS) is rising as patients are living longer with these more effective systemic therapies. Prolonged OS allows increased time to develop CNS metastases. The CNS is also a sanctuary for metastatic tumor cells that are protected from full exposure to therapeutic concentrations of most anticancer agents by the blood-brain barrier, the tumor microenvironment, and immune system. In addition, CNS metastases often develop late in the course of the disease, so patients are frequently heavily pretreated, resulting in drug resistance. Although genomic profiling has led to more effective therapies for systemic disease, the same therapy may not be effective in treating CNS disease, not only due to failure of blood-brain barrier penetration, but from discordance between the molecular profile in systemic and CNS tumor.

Activation of Grm1 expression by mutated BRaf (V600E) in vitro and in vivo

Our laboratory previously showed that ectopic expression of Grm1 is sufficient to induce spontaneous melanoma formation with 100% penetrance in transgenic mouse model, TG-3, which harbors wild-type BRaf. Studies identified Grm1 expression in human melanoma cell lines and primary to secondary metastatic melanoma biopsies having wild-type or mutated BRaf, but not in normal melanocytes or benign nevi. Grm1 expression was detected in tissues from mice genetically engineered with inducible melanocyte-specific BRaf^V600E. Additionally, stable clones derived from introduction of exogenous BRaf^V600E in mouse melanocytes also showed Grm1 expression, which was not detected in the parental or empty vector-derived cells, suggesting that expression of BRaf^V600E could activate Grm1 expression. Despite aberrant Grm1 expression in the inducible, melanocyte-specific BRaf^V600E mice, no tumors formed. However, in older mice, the melanocytes underwent senescence, as demonstrated previously by others. It was proposed that upregulated p15 and TGFβ contributed to the senescence phenotype. In contrast, in older TG-3 mice the levels of p15 and TGFβ remained the same or lower. Taken together, these results suggest the temporal regulation on the expression of "oncogenes" such as Grm1 or BRaf^V600E is critical in the future fate of the cells. If BRaf^V600E is turned on first, Grm1 expression can be induced, but this is not sufficient to result in development of melanoma; the cells undergo senescence. In contrast, if ectopic expression of Grm1 is turned on first, then regardless of wild-type or mutated BRaf in the melanocytes melanoma development is the consequence.

Targeted Therapies for the Treatment of Brain Metastases in Solid Tumors

Brain metastases are a major cause of morbidity and mortality in cancer patients. While the mainstay treatment comprises surgery and radiation therapy, the role of systemic agents remains controversial. In general, it has been presumed that poor blood-brain barrier (BBB) penetration and inherently more resistant metastatic brain disease preclude a favorable systemic treatment approach. However, a better understanding of tumor biology and the subsequent development of targeted drugs have reawakened interest in systemic therapy. Despite still limited brain distribution, a variety of targeted drugs have demonstrated activity in brain metastases in early clinical trials. Nevertheless, disease progression commonly occurs, and it remains to be elucidated whether limited CNS drug distribution or the acquisition of resistant metastatic clones must be held responsible for this prognosis. Moreover, micrometastatic brain disease beyond an intact BBB-and ultimately prevention of brain metastasis formation-may generally remain inaccessible for first-generation targeted agents with poor CNS penetration. To overcome limited brain distribution and possibly emerging acquired resistance, highly potent next-generation targeted drugs with enhanced CNS distribution have been developed. In view of this emerging but yet undefined role of targeted therapies in the treatment of brain metastases from solid tumors, this review aims to summarize the current knowledge from clinical trials and discusses clinically relevant obstacles to overcome.

Combining forces: the promise and peril of synergistic immune checkpoint blockade and targeted therapy in metastatic melanoma

Both immune checkpoint inhibitors and molecularly targeted agents have dramatically improved clinical outcomes for patients with metastatic melanoma. These two therapeutic approaches harness distinct mechanistic pathways-on the one hand, monoclonal antibodies against the immune checkpoints CTLA-4 and PD-1/PD-L1 stimulate the T cell mediated host immune response, while targeted inhibitors of the proto-oncogenes BRAF and MEK disrupt constitutive kinase activity responsible for tumor growth. The prospect of combining these two treatment modalities has been proposed as a potential way to increase overall response rate, extend durability of the anti-tumor response, and circumvent the immune-mediated resistance to targeted therapy. This review explores the preclinical rationale-building upon a wealth of in vitro and in vivo studies-for improved anti-tumor efficacy from combined immune checkpoint inhibition and targeted therapy. In the process, we detail the early clinical trials that have assessed the compatibility of combining these two therapies and the unexpected challenges faced from studies showing increased toxicity from these regimens. Ultimately, with more clinical data expected to mature and accrue in the near future, we elucidate a potentially novel and promising strategy for patients with advanced melanoma.

The impact of melanoma genetics on treatment response and resistance in clinical and experimental studies

Recent attempts to characterize the melanoma mutational landscape using high-throughput sequencing technologies have identified new genes and pathways involved in the molecular pathogenesis of melanoma. Apart from mutated BRAF, NRAS, and KIT, a series of new recurrently mutated candidate genes with impact on signaling pathways have been identified such as NF1, PTEN, IDH1, RAC1, ARID2, and TP53. Under targeted treatment using BRAF and MEK1/2 inhibitors either alone or in combination, a majority of patients experience recurrences, which are due to different genetic mechanisms such as gene amplifications of BRAF or NRAS, MEK1/2 and PI3K mutations. In principle, resistance mechanisms converge on two signaling pathways, MAPK and PI3K-AKT-mTOR pathways. Resistance may be due to small subsets of resistant cells within a heterogeneous tumor mass not identified by sequencing of the bulk tumor. Future sequencing studies addressing tumor heterogeneity, e.g., by using single-cell sequencing technology, will most likely improve this situation. Gene expression patterns of metastatic lesions were also shown to predict treatment response, e.g., a MITF-low/NF-κB-high melanoma phenotype is resistant against classical targeted therapies. Finally, more recent treatment approaches using checkpoint inhibitors directed against PD-1 and CTLA-4 are very effective in melanoma and other tumor entities. Here, the mutational and neoantigen load of melanoma lesions may help to predict treatment response. Taken together, the new sequencing, molecular, and bioinformatic technologies exploiting the melanoma genome for treatment decisions have significantly improved our understanding of melanoma pathogenesis, treatment response, and resistance for either targeted treatment or immune checkpoint blockade.

Genistein inhibits the growth and regulates the migration and invasion abilities of melanoma cells via the FAK/paxillin and MAPK pathways

Genistein is one of the main components of soy-based foods, which are widely known for their many benefits, including anti-cancer, anti-inflammatory, and antioxidant effects. In this study, we investigated the anti-metastasis effects of genistein on B16F10 melanoma cells. Our results showed that genistein strongly inhibited B16F10 cell proliferation and induced apoptosis in time- and concentration-dependent manners. Genistein altered the morphology of B16F10 cells to an elongated shape with slim pseudopodia-like protrusions. Moreover, genistein inhibited the invasion and migration abilities of B16F10 cells in a dose-dependent manner. On one hand, a high concentration of genistein (100 μM) significantly inhibited cell adhesion and migration, as shown by wound healing assays and transwell-migration and invasion assays. Furthermore, the expression levels of p-FAK, p-paxillin, tensin-2, vinculin, and α-actinin were decreased by genistein. As a result, genistein is believed to strongly downregulate the migration and invasion abilities of B16F10 cells via the FAK/paxillin pathway. Moreover, p-p38, p-ERK, and p-JNK levels were also dramatically decreased by treatment with genistein. Finally, genistein significantly decreased the gene expression of FAK, paxillin, vimentin, and epithelial-to-mesenchymal transition-related transcription factor Snail, as shown by real-time PCR (qPCR) analysis. On the other hand, a lower concentration of genistein (12.5 μM) significantly promoted both invasion and migration by activating the FAK/paxillin and MAPK signaling cascades. Taken together, this study showed for the first time that genistein exerts dual functional effects on melanoma cells. Our findings suggest that genistein regulates the FAK/paxillin and MAPK signaling pathways in a highly concentration-dependent manner. Patients with melanoma should therefore be cautious of consuming soy-based foods in their diets.

Precision medicine driven by cancer systems biology

Molecular insights from genome and systems biology are influencing how cancer is diagnosed and treated. We critically evaluate big data challenges in precision medicine. The melanoma research community has identified distinct subtypes involving chronic sun-induced damage and the mitogen-activated protein kinase driver pathway. In addition, despite low mutation burden, non-genomic mitogen-activated protein kinase melanoma drivers are found in membrane receptors, metabolism, or epigenetic signaling with the ability to bypass central mitogen-activated protein kinase molecules and activating a similar program of mitogenic effectors. Mutation hotspots, structural modeling, UV signature, and genomic as well as non-genomic mechanisms of disease initiation and progression are taken into consideration to identify resistance mutations and novel drug targets. A comprehensive precision medicine profile of a malignant melanoma patient illustrates future rational drug targeting strategies. Network analysis emphasizes an important role of epigenetic and metabolic master regulators in oncogenesis. Co-occurrence of driver mutations in signaling, metabolic, and epigenetic factors highlights how cumulative alterations of our genomes and epigenomes progressively lead to uncontrolled cell proliferation. Precision insights have the ability to identify independent molecular pathways suitable for drug targeting. Synergistic treatment combinations of orthogonal modalities including immunotherapy, mitogen-activated protein kinase inhibitors, epigenetic inhibitors, and metabolic inhibitors have the potential to overcome immune evasion, side effects, and drug resistance.

Crosstalk signaling in targeted melanoma therapy

Inhibition of the BRAF/MAPK pathway belongs to the standard therapies for patients with activating BRAF^V600E/K mutations. However, even in well-responding tumors, anti-tumorigenic effect and clinical benefit are only transient, and the original tumors often relapse. This demonstrates that there are remaining residual tumors, which have withstood therapy-induced apoptosis and which have the potential to resume growth. Although BRAF mutant melanoma cells seem to depend on BRAF/MAPK signaling, the inhibition of this pathway triggers several events, which modulate the tumor as well as the tumor niche. After a certain adaptation period, this can turn out to be beneficial for tumor growth and metastasis-even in cases of good initial tumor response. This review sheds light on the biology of BRAF/MEK inhibitor-sensitive melanoma cells, which survive targeted therapy and will address the crosstalk signaling events occurring in BRAF mutant melanomas when the BRAF/MAPK pathway is fully blocked. The knowledge of these events is important for potential future drug combinations, which enhance the inhibitory effect of BRAF/MEK inhibition, particularly in patients not eligible for immune therapy.

Metastatic BRAF K601E-mutated melanoma reaches complete response to MEK inhibitor trametinib administered for over 36 months

BACKGROUND

The BRAF K601E mutation occurs in 5% of patients with melanoma, and is the third most common type of BRAF mutation. However, treatment with BRAF and mitogen-activated extracellular signal-regulated kinase (MEK) inhibitors is only approved in patients with BRAF V600-positive melanoma, and patients with K601E-mutated melanoma do not have access to such drugs.

CASE PRESENTATION

A female patient was diagnosed with high tumor burden metastatic melanoma harboring the BRAF K601E mutation. After chemotherapy failure, she underwent compassionate treatment with trametinib. Trametinib showed good activity and efficacy, with 48% shrinkage of a metastatic lymphadenopathy after 4 months' treatment. However, the patient reported treatment-related skin toxicity that required dosage reduction and a personalized intermittent trametinib dosing schedule. After over 36 months from the first trametinib administration, and resection of a metastatic lymphadenopathy, the patient experienced complete response.

CONCLUSIONS

This case report shows that trametinib could be a valid therapeutic option in patients with metastatic melanoma harboring the rare BRAF K601E mutation.

The biology of uveal melanoma

Uveal melanoma (UM), a rare cancer of the eye, is distinct from cutaneous melanoma by its etiology, the mutation frequency and profile, and its clinical behavior including resistance to targeted therapy and immune checkpoint blockers. Primary disease is efficiently controlled by surgery or radiation therapy, but about half of UMs develop distant metastasis mostly to the liver. Survival of patients with metastasis is below 1 year and has not improved in decades. Recent years have brought a deep understanding of UM biology characterized by initiating mutations in the G proteins GNAQ and GNA11. Cytogenetic alterations, in particular monosomy of chromosome 3 and amplification of the long arm of chromosome 8, and mutation of the BRCA1-associated protein 1, BAP1, a tumor suppressor gene, or the splicing factor SF3B1 determine UM metastasis. Cytogenetic and molecular profiling allow for a very precise prognostication that is still not matched by efficacious adjuvant therapies. G protein signaling has been shown to activate the YAP/TAZ pathway independent of HIPPO, and conventional signaling via the mitogen-activated kinase pathway probably also contributes to UM development and progression. Several lines of evidence indicate that inflammation and macrophages play a pro-tumor role in UM and in its hepatic metastases. UM cells benefit from the immune privilege in the eye and may adopt several mechanisms involved in this privilege for tumor escape that act even after leaving the niche. Here, we review the current knowledge of the biology of UM and discuss recent approaches to UM treatment.

ERK Activation Globally Downregulates miRNAs through Phosphorylating Exportin-5

MicroRNAs (miRNA) are mostly downregulated in cancer. However, the mechanism underlying this phenomenon and the precise consequence in tumorigenesis remain obscure. Here we show that ERK suppresses pre-miRNA export from the nucleus through phosphorylation of exportin-5 (XPO5) at T345/S416/S497. After phosphorylation by ERK, conformation of XPO5 is altered by prolyl isomerase Pin1, resulting in reduction of pre-miRNA loading. In liver cancer, the ERK-mediated XPO5 suppression reduces miR-122, increases microtubule dynamics, and results in tumor development and drug resistance. Analysis of clinical specimens further showed that XPO5 phosphorylation is associated with poor prognosis for liver cancer patients. Our study reveals a function of ERK in miRNA biogenesis and suggests that modulation of miRNA export has potential clinical implications.

miR-217 regulates tumor growth and apoptosis by targeting the MAPK signaling pathway in colorectal cancer

MicroRNA (miR)-217 has been reported to participate in carcinogenesis and tumor progression in several cancers; however, its expression and biological functions in colorectal cancer (CRC) are still unclear. The present study demonstrated that miR-217 expression was significantly higher in matched adjacent noncancerous tissues than in CRC tissues (P<0.001). In addition, it was observed that low-grade CRC exhibited greater expression of miR-217 compared with high-grade CRC (P<0.05). Kaplan-Meier survival and Cox regression analyses revealed that overall survival rates were significantly poorer in the low-expression group relative to the high-expression group (P<0.005). Next, a potential miR-217 target, mitogen-activated protein kinase (MAPK) 1, was identified. Upregulation of miR-217 could significantly downregulate MAPK1 expression. CRC cells overexpressing miR-217 exhibited cell growth inhibition by significant enhancement of apoptosis in vitro. The present study further investigated the MAPK signaling pathway to verify the mechanisms, and revealed that KRAS and Raf-1 expression was downregulated in miR-217-overexpressing RKO cells. Taken together, our results revealed that miR-217 inhibits tumor growth and enhances apoptosis in CRC, and that this is associated with the downregulation of MAPK signaling. These results indicate that miR-217 is a promising therapeutic target for the treatment of CRC.

Magnetic Resonance Imaging and Spectroscopy in Cancer Theranostic Imaging

With its exquisite anatomical resolution and wide-ranging functional imaging capabilities, magnetic resonance imaging (MRI) has found multiple applications in detection, staging, and monitoring treatment response in cancer. The metabolic information provided by magnetic resonance spectroscopy (MRS) is being actively investigated to complement MRI parameters, as well as existing biomarkers, in cancer detection and in monitoring response to treatment. Located at the interface of detection and therapy, theranostic imaging is a rapidly expanding new field that is showing significant promise for precision medicine of cancer. Innovations in the development of novel nanoparticles decorated with imaging reporters that can be used to deliver therapeutic cargo to specific cells and environments have provided new roles for MRI and MRS in theranostic imaging.

Targeting the mitogen-activated protein kinase pathway in low-grade serous carcinoma of the ovary

Until recently, there has been little change in the management of epithelial ovarian cancer with the majority of women receiving identical systemic therapy, regardless of histological subtype. The heterogeneity of epithelial ovarian cancer is now well established, with distinct subtypes characterized by specific molecular alterations and patterns of clinical behavior. Low-grade serous carcinoma is a rare subtype associated with an indolent biological behavior and inherent resistance to chemotherapy. The mitogen-activated protein kinase pathway plays a prominent role in the pathogenesis of low-grade serous carcinoma, and provides an attractive target for novel therapeutic agents. Selumetinib, a MEK1/2 inhibitor, demonstrates promising efficacy in women with relapsed low-grade serous carcinoma, and further trials of MEK-inhibition are underway. Translational research will be essential to identify predictive biomarkers for this treatment approach.

Autophagy- An emerging target for melanoma therapy

Melanoma accounts for only 5% of all cancers but is the leading cause of skin cancer death due to its high metastatic potential. Patients with metastatic melanoma have a 10-year survival rate of less than 10%. While the clinical landscape for melanoma is evolving rapidly, lack of response to therapies, as well as resistance to therapy remain critical obstacles for treatment of this disease. In recent years, a myriad of therapy resistance mechanisms have been unravelled, one of which is autophagy, the focus of this review. In advanced stages of malignancy, melanoma cells hijack the autophagy machinery in order to alleviate drug-induced and metabolic stress in the tumor microenvironment, thereby promoting resistance to multiple therapies, tumor cell survival, and progression.  Autophagy is an essential cellular process that maintains cellular homeostasis through the recycling of intracellular constituents. Early studies on the role of autophagy in cancer generated controversy as to whether autophagy was pro- or anti-tumorigenic. Currently, there is a consensus that autophagy is tumor-suppressive in the early stages of cancer and tumor-promoting in established tumors.  This review aims to highlight current understandings on the role of autophagy in melanoma malignancy, and specifically therapy resistance; as well as to evaluate recent strategies for therapeutic autophagy modulation.

A novel integrative approach to identify lncRNAs associated with the survival of melanoma patients

Long non-coding RNAs (lncRNAs) play important roles in diagnosis and prognosis of human cancers. With the development of microarray and RNA-seq, gene expression were measured in more and more tumor types for identification of prognostic markers. However, lncRNA expression profiles of tumor patients with follow-up information were rare. In this study, we developed a novel simple computational approach, which didn't use lncRNA expression, to identify lncRNAs associated with the survival of melanoma patients through integrating gene expression and lncRNA-target networks. First, we calculated the significance of associations between gene expression and patients' survival. Second, we constructed the experimentally validated lncRNA-target gene networks. Next, the significance of lncRNAs were obtained by combination of the p-values of their neighbor genes. Finally, we identified 15 lncRNAs that were significantly associated with the survival of melanoma patients (p<0.05), which were supported by functional analysis and literature review. Collectively, this study provides an effective approach to predict the lncRNA signatures for outcomes of tumor patients without lncRNA expression profiles.

Butein inhibits metastatic behavior in mouse melanoma cells through VEGF expression and translation-dependent signaling pathway regulation

Background

Melanoma is an aggressive skin cancer and a predominant cause of skin cancer-related deaths. A previous study has demonstrated the ability of butein to inhibit tumor proliferation and invasion. However, the anti-metastatic mechanisms and in vivo effects of butein have not been fully elucidated.

Methods

MTT cell viability assays were used to evaluate the antitumor effects of butein in vitro. Cytotoxic effects of butein were measured by lactate dehydrogenase assay. Anti-migratory effects of butein were evaluated by two-dimensional scratch and transwell migration assays. Signaling transduction and VEGF-releasing assays were measured by Western blotting and ELISA. We also conducted an experimental analysis of the metastatic potential of tumor cells injected into the tail vein of C57BL/6 mice.

Results

We first demonstrated the effect of butein on cell viability at non-cytotoxic concentrations (1, 3, and 10 μM). In vitro, butein was found to inhibit the migration of B16F10 cells in a concentration-dependent manner using transwell and scratch assays. Butein had a dose-dependent effect on focal adhesion kinase, Akt, and ERK phosphorylation in B16F10 cells. Butein efficiently inhibited the mTOR/p70S6K translational inhibition machinery and decreased the production of VEGF in B16F10 cells. Furthermore, the in vivo antitumor effects of butein were demonstrated using a pulmonary metastasis model.

Conclusion

The results of the present study indicate the potential utility of butein in the treatment of melanoma.