Dabrafenib and its potential for the treatment of metastatic melanoma

KSR1 Knockout Mouse Model Demonstrates MAPK Pathway's Key Role in Cisplatin- and Noise-induced Hearing Loss

Hearing loss is a major disability in everyday life and therapeutic interventions to protect hearing would benefit a large portion of the world population. Here we found that mice devoid of the protein kinase suppressor of RAS 1 (KSR1) in their tissues (germline KO mice) exhibit resistance to both cisplatin- and noise-induced permanent hearing loss compared with their wild-type KSR1 littermates. KSR1 is a scaffold protein that brings in proximity the mitogen-activated protein kinase (MAPK) proteins BRAF, MEK1/2 and ERK1/2 and assists in their activation through a phosphorylation cascade induced by both cisplatin and noise insults in the cochlear cells. KSR1, BRAF, MEK1/2, and ERK1/2 are all ubiquitously expressed in the cochlea. Deleting the KSR1 protein tempered down the MAPK phosphorylation cascade in the cochlear cells following both cisplatin and noise insults and conferred hearing protection of up to 30 dB SPL in three tested frequencies in male and female mice. Treatment with dabrafenib, an FDA-approved oral BRAF inhibitor, protected male and female KSR1 wild-type mice from both cisplatin- and noise-induced hearing loss. Dabrafenib treatment did not enhance the protection of KO KSR1 mice, providing evidence dabrafenib works primarily through the MAPK pathway. Thus, either elimination of the KSR1 gene expression or drug inhibition of the MAPK cellular pathway in mice resulted in profound protection from both cisplatin- and noise-induced hearing loss. Inhibition of the MAPK pathway, a cellular pathway that responds to damage in the cochlear cells, can prove a valuable strategy to protect and treat hearing loss.

RhoA activation promotes glucose uptake to elevate proliferation in MAPK inhibitor resistant melanoma cells

Cutaneous melanomas harboring a B-RafV600E mutation are treated with immune check point inhibitors or kinase inhibitor combination therapies relying on MAPK inhibitors (MAPKi) Dabrafenib and Trametinib (Curti and Faries, 2021). However, cells become resistant to treatments over the timespan of a few months. Resistance to MAPKi has been associated with adoption of an aggressive amoeboid phenotype characterized by elevated RhoA signaling, enhanced contractility and thick cortical filamentous actin (F-actin) structures (Kim et al., 2016; Misek et al., 2020). Targeting active RhoA through Rho-kinase (ROCK) inhibitors, either alone or in combination with immunotherapies, reverts MAPKi-resistance (Misek et al., 2020; Orgaz et al., 2020). Yet, the mechanisms for this behavior remain largely unknown. Given our recent findings of cytoskeleton's role in cancer cell proliferation (Mohan et al., 2019), survival (Weems et al., 2023), and metabolism (Park et al., 2020), we explored possibilities by which RhoA-driven changes in cytoskeleton structure may confer resistance. We confirmed elevated activation of RhoA in a panel of MAPKi-resistant melanoma cell lines, leading to a marked increase in the presence of contractile F-actin bundles. Moreover, these cells had increased glucose uptake and glycolysis, a phenotype disrupted by pharmacological perturbation of ROCK. However, glycolysis was unaffected by disruption of F-actin bundles, indicating that glycolytic stimulation in MAPKi-resistant melanoma is independent of F-actin organization. Instead, our findings highlight a mechanism in which elevated RhoA signaling activates ROCK, leading to the activation of insulin receptor substrate 1 (IRS1) and P85 of the PI3K pathway, which promotes cell surface expression of GLUT1 and elevated glucose uptake. Application of ROCK inhibitor GSK269962A results in reduced glucose uptake and glycolysis, thus impeding cell proliferation. Our study adds a mechanism to the proposed use of ROCK inhibitors for long-term treatments on MAPKi-resistant melanomas.

The Cytoprotective Role of Autophagy in Response to BRAF-Targeted Therapies

BRAF-targeted therapies are widely used for the treatment of melanoma patients with BRAF V600 mutations. Vemurafenib, dabrafenib as well as encorafenib have demonstrated substantial therapeutic activity; however, as is the case with other chemotherapeutic agents, the frequent development of resistance limits their efficacy. Autophagy is one tumor survival mechanism that could contribute to BRAF inhibitor resistance, and multiple studies support an association between vemurafenib-induced and dabrafenib-induced autophagy and tumor cell survival. Clinical trials have also demonstrated a potential benefit from the inclusion of autophagy inhibition as an adjuvant therapy. This review of the scientific literature relating to the role of autophagy that is induced in response to BRAF-inhibitors supports the premise that autophagy targeting or modulation could be an effective adjuvant therapy.

Clonal differences underlie variable responses to sequential and prolonged treatment

Cancer cells exhibit dramatic differences in gene expression at the single-cell level which can predict whether they become resistant to treatment. Treatment perpetuates this heterogeneity, resulting in a diversity of cell states among resistant clones. However, it remains unclear whether these differences lead to distinct responses when another treatment is applied or the same treatment is continued. In this study, we combined single-cell RNA-sequencing with barcoding to track resistant clones through prolonged and sequential treatments. We found that cells within the same clone have similar gene expression states after multiple rounds of treatment. Moreover, we demonstrated that individual clones have distinct and differing fates, including growth, survival, or death, when subjected to a second treatment or when the first treatment is continued. By identifying gene expression states that predict clone survival, this work provides a foundation for selecting optimal therapies that target the most aggressive resistant clones within a tumor.

Evolution of the Targeted Therapy Landscape for Cholangiocarcinoma: Is Cholangiocarcinoma the 'NSCLC' of GI Oncology?

In the past two decades, molecular targeted therapy has revolutionized the treatment landscape of several malignancies. Lethal malignancies such as non-small cell lung cancer (NSCLC) have become a model for precision-matched immune- and gene-targeted therapies. Multiple small subgroups of NSCLC defined by their genomic aberrations are now recognized; remarkably, taken together, almost 70% of NSCLCs now have a druggable anomaly. Cholangiocarcinoma (CCA) is a rare tumor with a poor prognosis. Novel molecular alterations have been recently identified in patients with CCA, and the potential for targeted therapy is being realized. In 2019, a fibroblast growth factor receptor 2 (FGFR2) inhibitor, pemigatinib, was the first approved targeted therapy for patients with locally advanced or metastatic intrahepatic CCA who had FGFR2 gene fusions or rearrangement. More regulatory approvals for matched targeted therapies as second-line or subsequent treatments in advanced CCA followed, including additional drugs that target FGFR2 gene fusion/rearrangement. Recent tumor-agnostic approvals include (but are not limited to) drugs that target mutations/rearrangements in the following genes and are hence applicable to CCA: isocitrate dehydrogenase 1 (IDH1); neurotrophic tropomyosin-receptor kinase (NTRK); the V600E mutation of the BRAF gene (BRAFV600E); and high tumor mutational burden, high microsatellite instability, and gene mismatch repair-deficient (TMB-H/MSI-H/dMMR) tumors. Ongoing trials investigate HER2, RET, and non-BRAFV600E mutations in CCA and improvements in the efficacy and safety of new targeted treatments. This review aims to present the current status of molecularly matched targeted therapy for advanced CCA.

Nitrogen Containing Heterocycles as Anticancer Agents: A Medicinal Chemistry Perspective

Cancer is one of the major healthcare challenges across the globe. Several anticancer drugs are available on the market but they either lack specificity or have poor safety, severe side effects, and suffer from resistance. So, there is a dire need to develop safer and target-specific anticancer drugs. More than 85% of all physiologically active pharmaceuticals are heterocycles or contain at least one heteroatom. Nitrogen heterocycles constituting the most common heterocyclic framework. In this study, we have compiled the FDA approved heterocyclic drugs with nitrogen atoms and their pharmacological properties. Moreover, we have reported nitrogen containing heterocycles, including pyrimidine, quinolone, carbazole, pyridine, imidazole, benzimidazole, triazole, β-lactam, indole, pyrazole, quinazoline, quinoxaline, isatin, pyrrolo-benzodiazepines, and pyrido[2,3-d]pyrimidines, which are used in the treatment of different types of cancer, concurrently covering the biochemical mechanisms of action and cellular targets.

MAPK Pathways in Ocular Pathophysiology: Potential Therapeutic Drugs and Challenges

Mitogen-activated protein kinase (MAPK) pathways represent ubiquitous cellular signal transduction pathways that regulate all aspects of life and are frequently altered in disease. Once activated through phosphorylation, these MAPKs in turn phosphorylate and activate transcription factors present either in the cytoplasm or in the nucleus, leading to the expression of target genes and, as a consequence, they elicit various biological responses. The aim of this work is to provide a comprehensive review focusing on the roles of MAPK signaling pathways in ocular pathophysiology and the potential to influence these for the treatment of eye diseases. We summarize the current knowledge of identified MAPK-targeting compounds in the context of ocular diseases such as macular degeneration, cataract, glaucoma and keratopathy, but also in rare ocular diseases where the cell differentiation, proliferation or migration are defective. Potential therapeutic interventions are also discussed. Additionally, we discuss challenges in overcoming the reported eye toxicity of some MAPK inhibitors.

Options of Therapeutics and Novel Delivery Systems of Drugs for the Treatment of Melanoma

Melanoma is one of the most severe cancerous diseases. The cells employ multiple signaling pathways, such as ERK, HGF/c-MET, WNT, and COX-2 to cause the cell proliferation, survival, and metastasis. Treatment of melanoma, including surgery, chemotherapy, immunotherapy, radiation, and targeted therapy, is based on 4 major or 11 substages of the disease. Fourteen drugs, including dacarbazine, interferon α-2b, interleukin-12, ipilimumab, peginterferon α-2b, vemurafenib, trametinib, talimogene laherparepvec, cobimetinib, pembrolizumab, dabrafenib, binimetinib, encorafenib, and nivolumab, have been approved by the FDA for the treatment of melanoma. All of them are in conventional dosage forms of injection solutions, suspensions, oral tablets, or capsules. Major drawbacks of the treatment are side effects of the drugs and patients' incompliance to them. These are consequences of high doses and long-term treatments for the diseases. Currently more than 350 NCI-registered clinical trials are being carried out to treat advanced and/or metastatic melanoma using novel treatment methods, such as immune cell therapy, cancer vaccines, and new therapeutic targets. In addition, novel delivery systems using biomaterials of the approved drugs have been developed attempting to increase the drug delivery, targeting, stability, bioavailability, thus potentially reducing the toxicity and increasing the treatment effectiveness. Nanoparticles and liposomes have been emerging as advanced delivery systems which can improve drug stability and systemic circulation time. In this review, the most recent findings in the options for treatment and development of novel drug delivery systems for the treatment of melanoma are comprehensively discussed.

CRISPR/Cas9 Edited RAS & MEK Mutant Cells Acquire BRAF and MEK Inhibitor Resistance with MEK1 Q56P Restoring Sensitivity to MEK/BRAF Inhibitor Combo and KRAS G13D Gaining Sensitivity to Immunotherapy

Simple Summary

BRAF inhibitor drug resistance has been a long-time challenge in the treatment of melanoma with BRAF V600E mutation. This study employed the CRISPR/Cas9 technology to generate three isogenic A375 melanoma cell lines with point mutations of NRAS Q61K, KRAS G13D and MEK1 Q56P, respectively. They recapitulated the resistance to BRAF inhibitors in vitro as such mutations have been found in patients with acquired resistance to BRAF inhibitors during treatment. Hence, these novel isogenic cell lines become extremely useful tools for upcoming research in this field. Additionally, we determined that resistance in the NRAS and MEK isogenic lines is driven by constitutive MEK/ERK signaling, while the resistance in the KRAS isogenic line is driven by EGFR overexpression. The KRAS G13D isogenic line displays elevated PD-L1 expression suggesting the KRAS G13D mutation could be a potential indication for immunotherapy.

Abstract

BRAF V600E mutation drives uncontrolled cell growth in most melanomas. While BRAF V600E tumors are initially responsive to BRAF inhibitors, prolonged treatment results in inhibitor resistance and tumor regrowth. Clinical data have linked the NRAS Q61K, KRAS G13D and MEK1 Q56P mutations to the BRAF inhibitor resistance. However, development of novel therapeutics is hindered by the lack of relevant isogeneic cell models. We employed CRISPR/Cas9 genome engineering to introduce NRAS Q61K, KRAS G13D and MEK1 Q56P mutations into the A375 melanoma cell line with endogenously high expression of BRAF V600E. The resulting isogenic cell lines are resistant to BRAF inhibitors. The A375 MEK1 Q56P isogenic cells are additionally resistant to MEK inhibitors as single agent, but interestingly, these cells become sensitive to MEK/BRAF inhibitor combo. Our results suggest that resistance in the NRAS and MEK isogenic lines is driven by constitutive MEK/ERK signaling, while the resistance in the KRAS isogenic line is driven by EGFR overexpression. Interestingly, the KRAS G13D isogenic line displays elevated PD-L1 expression suggesting the KRAS G13D mutation could be a potential indication for immunotherapy. Overall, these three novel isogenic cell models with endogenous level RAS and MEK1 point mutations provide direct bio-functional evidence demonstrating that acquiring a drug-resistant gene drives tumor cell survival and may simultaneously introduce new indications for combo therapy or immunotherapy in the clinic.

Gene Identification and Potential Drug Therapy for Drug-Resistant Melanoma with Bioinformatics and Deep Learning Technology

Background. Melanomas are skin malignant tumors that arise from melanocytes which are primarily treated with surgery, chemotherapy, targeted therapy, immunotherapy, radiation therapy, etc. Targeted therapy is a promising approach to treating advanced melanomas, but resistance always occurs. This study is aimed at identifying the potential target genes and candidate drugs for drug-resistant melanoma effectively with computational methods. Methods. Identification of genes associated with drug-resistant melanomas was conducted using the text mining tool pubmed2ensembl. Further gene screening was carried out by GO and KEGG pathway enrichment analyses. The PPI network was constructed using STRING database and Cytoscape. GEPIA was used to perform the survival analysis and conduct the Kaplan-Meier curve. Drugs targeted at these genes were selected in Pharmaprojects. The binding affinity scores of drug-target interactions were predicted by DeepPurpose. Results. A total of 433 genes were found associated with drug-resistant melanomas by text mining. The most statistically differential functional enriched pathways of GO and KEGG analyses contained 348 genes, and 27 hub genes were further screened out by MCODE in Cytoscape. Six genes were identified with statistical differences after survival analysis and literature review. 16 candidate drugs targeted at hub genes were found by Pharmaprojects under our restrictions. Finally, 11 ERBB2-targeted drugs with top affinity scores were predicted by DeepPurpose, including 10 ERBB2 kinase inhibitors and 1 antibody-drug conjugate. Conclusion. Text mining and bioinformatics are valuable methods for gene identification in drug discovery. DeepPurpose is an efficient and operative deep learning tool for predicting the DTI and selecting the candidate drugs.

Changes in the Transcriptome and Chromatin Landscape in BRAFi-Resistant Melanoma Cells

Metastatic and drug-resistant melanoma are leading causes of skin cancer-associated death. Mitogen-associated protein kinase (MAPK) pathway inhibitors and immunotherapies have provided substantial benefits to patients with melanoma. However, long-term therapeutic efficacy has been limited due to emergence of treatment resistance. Despite the identification of several molecular mechanisms underlying the development of resistant phenotypes, significant progress has still not been made toward the effective treatment of drug-resistant melanoma. Therefore, the identification of new targets and mechanisms driving drug resistance in melanoma represents an unmet medical need. In this study, we performed unbiased RNA-sequencing (RNA-seq) and assay for transposase-accessible chromatin with sequencing (ATAC-seq) to identify new targets and mechanisms that drive resistance to MAPK pathway inhibitors targeting BRAF and MAPK kinase (MEK) in BRAF-mutant melanoma cells. An integrative analysis of ATAC-seq combined with RNA-seq showed that global changes in chromatin accessibility affected the mRNA expression levels of several known and novel genes, which consequently modulated multiple oncogenic signaling pathways to promote resistance to MAPK pathway inhibitors in melanoma cells. Many of these genes were also associated with prognosis predictions in melanoma patients. This study resulted in the identification of new genes and signaling pathways that might be targeted to treat MEK or BRAF inhibitors resistant melanoma patients. The present study applied new and advanced approaches to identify unique changes in chromatin accessibility regions that modulate gene expression associated with pathways to promote the development of resistance to MAPK pathway inhibitors.

Combination Strategies Involving Immune Checkpoint Inhibitors and Tyrosine Kinase or BRAF Inhibitors in Aggressive Thyroid Cancer

Thyroid cancer is the most common (~90%) type of endocrine-system tumor, accounting for 70% of the deaths from endocrine cancers. In the last years, the high-throughput genomics has been able to identify pathways/molecular targets involved in survival and tumor progression. Targeted therapy and immunotherapy individually have many limitations. Regarding the first one, although it greatly reduces the size of the cancer, clinical responses are generally transient and often lead to cancer relapse after initial treatment. For the second one, although it induces longer-lasting responses in cancer patients than targeted therapy, its response rate is lower. The individual limitations of these two different types of therapies can be overcome by combining them. Here, we discuss MAPK pathway inhibitors, i.e., BRAF and MEK inhibitors, combined with checkpoint inhibitors targeting PD-1, PD-L1, and CTLA-4. Several mutations make tumors resistant to treatments. Therefore, more studies are needed to investigate the patient's individual tumor mutation burden in order to overcome the problem of resistance to therapy and to develop new combination therapies.

FDA-Approved Small Molecule Compounds as Drugs for Solid Cancers from Early 2011 to the End of 2021

Solid cancers are the most common types of cancers diagnosed globally and comprise a large number of deaths each year. The main challenge currently in drug development for tumors raised from solid organs is to find more selective compounds, which exploit specific molecular targets. In this work, the small molecule drugs registered by the Food and Drug Administration (FDA) for solid cancers treatment between 2011 and 2022 were identified and analyzed by investigating a type of therapy they are used for, as well as their structures and mechanisms of action. On average, 4 new small molecule agents were introduced each year, with a few exceptions, for a total of 62 new drug approvals. A total of 50 of all FDA-approved drugs have also been authorized for use in the European Union by the European Medicines Agency (EMA). Our analysis indicates that many more anticancer molecules show a selective mode of action, i.e., 49 targeted agents, 5 hormone therapies and 3 radiopharmaceuticals, compared to less specific cytostatic action, i.e., 5 chemotherapeutic agents. It should be emphasized that new medications are indicated for use mainly for monotherapy and less for a combination or adjuvant therapies. The comprehensive data presented in this review can serve for further design and development of more specific targeted agents in clinical usage for solid tumors.

Naturally occurring, natural product inspired and synthetic heterocyclic anti-cancer drugs

This chapter describes the importance and activity of a huge number of commercially available naturally occurring, natural product derived or synthetic heterocyclic anti-cancer drugs.

Magnetic nanoparticles in theranostics of malignant melanoma

Malignant melanoma is an aggressive tumor with a tendency to metastasize early and with an increasing incidence worldwide. Although in early stage, melanoma is well treatable by excision, the chances of cure and thus the survival rate decrease dramatically after metastatic spread. Conventional treatment options for advanced disease include surgical resection of metastases, chemotherapy, radiation, targeted therapy and immunotherapy. Today, targeted kinase inhibitors and immune checkpoint blockers have for the most part replaced less effective chemotherapies. Magnetic nanoparticles as novel agents for theranostic purposes have great potential in the treatment of metastatic melanoma. In the present review, we provide a brief overview of treatment options for malignant melanoma with different magnetic nanocarriers for theranostics. We also discuss current efforts of designing magnetic particles for combined, multimodal therapies (e.g., chemotherapy, immunotherapy) for malignant melanoma.

Primary Retroperitoneal Malignant Melanoma with Involvement of Iliac Artery and Vein

Primary retroperitoneal melanoma is a very rare extracutaneous presentation of melanoma. In this case report, we present a 65-year-old female with unilateral lower extremity edema secondary to occlusion of iliac vessels by a primary retroperitoneal melanoma tumor. We also review the findings in other cases previously described in the literature.

Clinical Pharmacokinetics and Pharmacodynamics of Dabrafenib

Dabrafenib is a potent and selective inhibitor of BRAF-mutant kinase that is approved, as monotherapy or in combination with trametinib (mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor), for unresectable or metastatic BRAF-mutated melanoma, advanced non-small cell lung cancer and anaplastic thyroid cancer harbouring the BRAF^V600E mutation. The recommended dose of dabrafenib is 150 mg twice daily (bid) under fasted conditions. After single oral administration of the recommended dose, the absolute oral bioavailability (F) of dabrafenib is 95%. Dabrafenib shows a time-dependent increase in apparent clearance (CL/F) following multiple doses, which is likely due to induction of its own metabolism through cytochrome P450 (CYP) 3A4. Therefore, steady state is reached only after 14 days of daily dose administration. Moreover, the extent of this auto-induction process is dependent on the dose, which explains why dabrafenib systemic exposure at steady state increases less than dose proportionally over the dose range of 75-300 mg bid. The main elimination route of dabrafenib is the oxidative metabolism via CYP3A4/2C8 and biliary excretion. Among the three major metabolites identified, hydroxy-dabrafenib appears to contribute to the pharmacological activity. Age, sex and body weight did not have any clinically significant influence on plasma exposure to dabrafenib. No dose adjustment is needed for patients with mild renal or hepatic impairment, whereas the impacts of severe impairment on dabrafenib pharmacokinetics remain unknown. Considering that dabrafenib is a substrate of CYP3A4/2C8 and is a CYP3A4/2B6/2C inducer, drug-drug interactions are expected with dabrafenib. The relationship between clinical outcomes and plasma exposure to dabrafenib and hydroxy-dabrafenib should be investigated more deeply.

Pharmacological STING Activation Is a Potential Alternative to Overcome Drug-Resistance in Melanoma

Melanoma is the most aggressive type of skin cancer and resistance to the conventional chemotherapy is the major cause for its poor prognosis. Metabolic perturbations leading to increased production of reactive oxygen species activate NRF2-dependent anti-oxidative responses to survive oxidative stress. This protective function of NRF2 is the primary cause for therapy resistance in cancer as anti-cancer agents such as BRAF inhibitors also induce NRF2-dependent antioxidative response. We had reported that type I interferons produced upon activation of STING, abrogates NRF2 function. Therefore, we investigated if STING agonists such as the newly developed dimeric aminobenzimidazole (diABZI) could sensitize melanoma cells to the clinically used BRAF inhibitors. Our results reveal that pharmacological activation of STING by diABZI, down regulates NRF2-dependent anti-oxidative responses and potentiates cell-death in melanoma cells when used in combination with BRAF inhibitors.

Functional Roles of Matrix Metalloproteinases and Their Inhibitors in Melanoma

The extracellular matrix (ECM) plays an important role in the regulation of the tissue microenvironment and in the maintenance of cellular homeostasis. Several proteins with a proteolytic activity toward several ECM components are involved in the regulation and remodeling of the ECM. Among these, Matrix Metalloproteinases (MMPs) are a class of peptidase able to remodel the ECM by favoring the tumor invasive processes. Of these peptidases, MMP-9 is the most involved in the development of cancer, including that of melanoma. Dysregulations of the MAPKs and PI3K/Akt signaling pathways can lead to an aberrant overexpression of MMP-9. Even ncRNAs are implicated in the aberrant production of MMP-9 protein, as well as other proteins responsible for the activation or inhibition of MMP-9, such as Osteopontin and Tissue Inhibitors of Metalloproteinases. Currently, there are different therapeutic approaches for melanoma, including targeted therapies and immunotherapies. However, no biomarkers are available for the prediction of the therapeutic response. In this context, several studies have tried to understand the diagnostic, prognostic and therapeutic potential of MMP-9 in melanoma patients by performing clinical trials with synthetic MMPs inhibitors. Therefore, MMP-9 may be considered a promising molecule for the management of melanoma patients due to its role as a biomarker and therapeutic target.

Secondary Resistant Mutations to Small Molecule Inhibitors in Cancer Cells

Secondary resistant mutations in cancer cells arise in response to certain small molecule inhibitors. These mutations inevitably cause recurrence and often progression to a more aggressive form. Resistant mutations may manifest in various forms. For example, some mutations decrease or abrogate the affinity of the drug for the protein. Others restore the function of the enzyme even in the presence of the inhibitor. In some cases, resistance is acquired through activation of a parallel pathway which bypasses the function of the drug targeted pathway. The Catalogue of Somatic Mutations in Cancer (COSMIC) produced a compendium of resistant mutations to small molecule inhibitors reported in the literature. Here, we build on these data and provide a comprehensive review of resistant mutations in cancers. We also discuss mechanistic parallels of resistance.

Current Insights into Combination Therapies with MAPK Inhibitors and Immune Checkpoint Blockade

The recent development of high-throughput genomics has revolutionized personalized medicine by identifying key pathways and molecular targets controlling tumor progression and survival. Mitogen-activated protein kinase (MAPK) pathways are examples of such targets, and inhibitors against these pathways have shown promising clinical responses in patients with melanoma, non-small-cell lung cancer, colorectal cancer, pancreatic cancer, and thyroid cancer. Although MAPK pathway-targeted therapies have resulted in significant clinical responses in a large proportion of cancer patients, the rate of tumor recurrence is high due to the development of resistance. Conversely, immunotherapies have shown limited clinical responses, but have led to durable tumor regression in patients, and complete responses. Recent evidence indicates that MAPK-targeted therapies may synergize with immune cells, thus providing rationale for the development of combination therapies. Here, we review the current status of ongoing clinical trials investigating MAPK pathway inhibitors, such as BRAF and MAPK/ERK kinase (MEK) inhibitors, in combination with checkpoint inhibitors targeting programmed death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic T cell associated antigen-4 (CTLA-4). A better understanding of an individual drug's mechanism of action, patterns of acquired resistance, and the influence on immune cells will be critical for the development of novel combination therapies.

Novel HSP90-PI3K Dual Inhibitor Suppresses Melanoma Cell Proliferation by Interfering with HSP90-EGFR Interaction and Downstream Signaling Pathways

Melanoma is the deadliest form of skin cancer, and its incidence has continuously increased over the past 20 years. Therefore, the discovery of a novel targeted therapeutic strategy for melanoma is urgently needed. In our study, MTT-based cell proliferation assay, cell cycle, and apoptosis assays through flow cytometry, protein immunoblotting, protein immunoprecipitation, designing of melanoma xenograft models, and immunohistochemical/immunofluorescent assays were carried out to determine the detailed molecular mechanisms of a novel HSP90-PI3K dual inhibitor. Our compound, named DHP1808, was found to suppress A375 cell proliferation through apoptosis induction by activating the Fas/FasL signaling pathway; it also induced cell-cycle arrest and inhibited the cell migration and invasion of A375 cells by interfering with Hsp90-EGFR interactions and downstream signaling pathways. Our results indicate that DHP1808 could be a promising lead compound for the Hsp90/PI3K dual inhibitor.

Current Advances in the Treatment of BRAF-Mutant Melanoma

Melanoma is the most lethal form of skin cancer. Melanoma is usually curable with surgery if detected early, however, treatment options for patients with metastatic melanoma are limited and the five-year survival rate for metastatic melanoma had been 15-20% before the advent of immunotherapy. Treatment with immune checkpoint inhibitors has increased long-term survival outcomes in patients with advanced melanoma to as high as 50% although individual response can vary greatly. A mutation within the MAPK pathway leads to uncontrollable growth and ultimately develops into cancer. The most common driver mutation that leads to this characteristic overactivation in the MAPK pathway is the B-RAF mutation. Current combinations of BRAF and MEK inhibitors that have demonstrated improved patient outcomes include dabrafenib with trametinib, vemurafenib with cobimetinib or encorafenib with binimetinib. Treatment with BRAF and MEK inhibitors has met challenges as patient responses began to drop due to the development of resistance to these inhibitors which paved the way for development of immunotherapies and other small molecule inhibitor approaches to address this. Resistance to these inhibitors continues to push the need to expand our understanding of novel mechanisms of resistance associated with treatment therapies. This review focuses on the current landscape of how resistance occurs with the chronic use of BRAF and MEK inhibitors in BRAF-mutant melanoma and progress made in the fields of immunotherapies and other small molecules when used alone or in combination with BRAF and MEK inhibitors to delay or circumvent the onset of resistance for patients with stage III/IV BRAF mutant melanoma.

Lycorine Induces autophagy-associated apoptosis by targeting MEK2 and enhances vemurafenib activity in colorectal cancer

Lycorine is a powerful anti-cancer agent against various cancer cell lines with minor side effects. However, the detailed mechanisms of its effects in colorectal cancer (CRC) remain unclear. In this study, we investigated the function and mechanism of lycorine against CRC both in vitro and in vivo. Molecular docking modeling was used to identify potential inhibitory targets of lycorine in CRC. Cell viability was measured using the Cell Counting Kit-8 assay, and apoptosis was measured using flow cytometry. Autophagosomes were examined using transmission electron microscopy and confocal microscopy. HCT116-derived xenografts were constructed to analyze the effect of lycorine in CRC in vivo. Using the CDOCKER algorithm, we determined that lycorine has four interactions with the conserved domain of mitogen-activated protein kinase kinase 2 (MEK2). This prediction was further confirmed by the degradation of phosphorylated MEK2 and its downstream targets after lycorine treatment, and MEK2 overexpression abolished lycorine-induced autophagy-associated apoptosis. Additionally, we revealed that the combination of vemurafenib and lycorine had better effects in CRC models in vitro and in vivo than monotherapy. Our findings identified lycorine as an effective MEK2 inhibitor and suggested that the combination of lycorine and vemurafenib could be used to treat CRC.

Dabrafenib in BRAFV600E mutant pilocytic astrocytoma in a pediatric patient

Pilocytic astrocytomas (PAs) are the most common pediatric central nervous system tumors. They constitute around 30% of all primary central nervous tumors in the pediatric age group. Their clinical behavior may vary but most of them are indolent and do not undergo malignant transformations compared with their adult counterparts. PAs are primarily treated with surgery and in cases of progression; chemotherapy may be needed. They usually carry a good prognosis, with a 10-year survival rate of 90%. BRAFV600E mutations have been identified in approximately 9-15% of patients with PA. These relatively high mutation frequencies in PA open avenues for treatment using targeted therapies such as BRAFV600E inhibitors (e.g., dabrafenib). There have been a few published case reports and case series showing clinical benefits with BRAF inhibitors in BRAF-positive tumors. We report a case of successful treatment of BRAFV600E immunopositive optic pathway PA in a child with dabrafenib.

Newly diagnosed papillary craniopharyngioma with BRAF V600E mutation treated with single-agent selective BRAF inhibitor dabrafenib: a case report

We report a case of a patient with newly diagnosed, locally extensive and cystic, suprasellar papillary craniopharyngioma successfully treated with single-agent Dabrafenib. The patient was symptomatic with gait imbalance with falls, lethargic episodes, fatigue and incontinence. Diagnostic imaging demonstrated a cystic suprasellar tumor extending into the third ventricle causing obstructive hydrocephalus. The tumor was partially debulked, and bilateral shunts were placed. NGS sequencing demonstrated BRAF V600E mutation, and the patient was prescribed dual agent Dabrafenib and Trametinib. However, due to insurance denial for Trametinib, he only received single-agent Dabrafenib (150mg BID). The treatment resulted in a major response (over two years), including reduction of the tumor cyst, and improvement of the clinical symptoms. No adverse events have been reported. The patient continues on Dabrafenib (150 mg BID) with a steady reduction in tumor size, and improvement in cognitive function leading to independent living.

Distinct Molecular Profiles and Immunotherapy Treatment Outcomes of V600E and V600K BRAF-Mutant Melanoma

PURPOSE

BRAF V600E and V600K melanomas have distinct clinicopathologic features, and V600K appear to be less responsive to BRAFi±MEKi. We investigated mechanisms for this and explored whether genotype affects response to immunotherapy.

EXPERIMENTAL DESIGN

Pretreatment formalin-fixed paraffin-embedded tumors from patients treated with BRAFi±MEKi underwent gene expression profiling and DNA sequencing. Molecular results were validated using The Cancer Genome Atlas (TCGA) data. An independent cohort of V600E/K patients treated with anti-PD-1 immunotherapy was examined.

RESULTS

Baseline tissue and clinical outcome with BRAFi±MEKi were studied in 93 patients (78 V600E, 15 V600K). V600K patients had numerically less tumor regression (median, -31% vs. -52%, P = 0.154) and shorter progression-free survival (PFS; median, 5.7 vs. 7.1 months, P = 0.15) compared with V600E. V600K melanomas had lower expression of the ERK pathway feedback regulator dual-specificity phosphatase 6, confirmed with TCGA data (116 V600E, 17 V600K). Pathway analysis showed V600K had lower expression of ERK and higher expression of PI3K-AKT genes than V600E. Higher mutational load was observed in V600K, with a higher proportion of mutations in PIK3R1 and tumor-suppressor genes. In patients treated with anti-PD-1, V600K (n = 19) had superior outcomes than V600E (n = 84), including response rate (53% vs. 29%, P = 0.059), PFS (median, 19 vs. 2.7 months, P = 0.049), and overall survival (20.4 vs. 11.7 months, P = 0.081).

CONCLUSIONS

BRAF V600K melanomas appear to benefit less from BRAFi±MEKi than V600E, potentially due to less reliance on ERK pathway activation and greater use of alternative pathways. In contrast, these melanomas have higher mutational load and respond better to immunotherapy.

Kinase inhibitor library screening identifies synergistic drug combinations effective in sensitive and resistant melanoma cells

Background

Melanoma is the most aggressive and deadly form of skin cancer with increasing case numbers worldwide. The development of inhibitors targeting mutated BRAF (found in around 60% of melanoma patients) has markedly improved overall survival of patients with late-stage tumors, even more so when combined with MEK inhibitors targeting the same signaling pathway. However, invariably patients become resistant to this targeted therapy resulting in rapid progression with treatment-refractory disease. The purpose of this study was the identification of new kinase inhibitors that do not lead to the development of resistance in combination with BRAF inhibitors (BRAFi), or that could be of clinical benefit as a 2nd line treatment for late-stage melanoma patients that have already developed resistance.

Methods

We have screened a 274-compound kinase inhibitor library in 3 BRAF mutant melanoma cell lines (each one sensitive or made resistant to 2 distinct BRAFi). The screening results were validated by dose-response studies and confirmed the killing efficacies of many kinase inhibitors. Two different tools were applied to investigate and quantify potential synergistic effects of drug combinations: the Chou-Talalay method and the Synergyfinder application. In order to exclude that resistance to the new treatments might occur at later time points, synergistic combinations were administered to fluorescently labelled parental and resistant cells over a period of > 10 weeks.

Results

Eight inhibitors targeting Wee1, Checkpoint kinase 1/2, Aurora kinase, MEK, Polo-like kinase, PI3K and Focal adhesion kinase killed melanoma cells synergistically when combined with a BRAFi. Additionally, combination of a Wee1 and Chk inhibitor showed synergistic killing effects not only on sensitive cell lines, but also on intrinsically BRAFi- and treatment induced-resistant melanoma cells. First in vivo studies confirmed these observations. Interestingly, continuous treatment with several of these drugs, alone or in combination, did not lead to emergence of resistance.

Conclusions

Here, we have identified new, previously unexplored (in the framework of BRAFi resistance) inhibitors that have an effect not only on sensitive but also on BRAFi-resistant cells. These promising combinations together with the new immunotherapies could be an important step towards improved 1st and 2nd line treatments for late-stage melanoma patients.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1038-x) contains supplementary material, which is available to authorized users.

Investigating Cell Signaling with Gene Expression Datasets

Modern molecular biology is a data- and computationally-intensive field with few instructional resources for introducing undergraduate students to the requisite skills and techniques for analyzing large data sets. This Lesson helps students: (i) build an understanding of the role of signal transduction in the control of gene expression; (ii) improve written scientific communication skills through engagement in literature searches, data analysis, and writing reports; and (iii) develop an awareness of the procedures and protocols for analyzing and making inferences from high-content quantitative molecular biology data. The Lesson is most suited to upper level biology courses because it requires foundational knowledge on cellular organization, protein structure and function, and the tenets of information flow from DNA to proteins. The first step lays the foundation for understanding cell signaling, which can be accomplished through assigned readings and presentations. In subsequent active learning sessions, data analysis is integrated with exercises that provide insight into the structure of scientific papers. The Lesson emphasizes the role of quantitative methods in research and helps students gain experience with functional genomics databases and data analysis, which are important skills for molecular biologists. Assessment is conducted through mini-reports designed to gauge students' perceptions of the purpose of each step, their awareness of the possible limitations of the methods utilized, and the ability to identify opportunities for further investigation. Summative assessment is conducted through a final report. The modules are suitable for complementing wet-laboratory experiments and can be adapted for different courses that use molecular biology data.

Melanoma cells resistant towards MAPK inhibitors exhibit reduced TAp73 expression mediating enhanced sensitivity to platinum-based drugs

The efficacy of targeted MAPK signalling pathway inhibitors (MAPKi) in metastatic melanoma therapy is limited by the development of resistance mechanisms that results in disease relapse. This situation still requires treatment alternatives for melanoma patients with acquired resistance to targeted therapy. We found that melanoma cells, which developed resistance towards MAPKi show an enhanced susceptibility to platinum-based drugs, such as cisplatin and carboplatin. We found that this enhanced susceptibility inversely correlates with the expression level of the p53 family member TAp73. We show that the lower expression of the TAp73 isoform in MAPKi-resistant melanoma cells enhances accumulation of DNA double-strand breaks upon cisplatin and carboplatin treatment by reducing the efficiency of nucleotide excision repair. These data suggest that a subgroup of melanoma patients with acquired resistance to MAPKi treatment and low TAp73 expression can benefit from chemotherapy with platinum-based drugs as a second-line therapy.

Dabrafenib and Trametinib Treatment for Erdheim-Chester Disease With Brain Stem Involvement

Erdheim-Chester disease (ECD) is a rare form of non–Langerhans cell histiocytosis characterized by infiltration of organs by CD68⁺ and CD1a⁻ lipid-laden histiocytes, including the central nervous system in more than a third of patients. Molecular analysis of ECD samples has demonstrated the prevalence of BRAF V600E mutations as high as 54%. Recently, vemurafenib became the only Food and Drug Administration–approved treatment for patients with ECD who carry the BRAF V600E mutation. However, dabrafenib has been suggested to have greater brain distribution. We describe a 44-year-old female patient treated from August of 2015 through November 2017. She presented with a 2-year history of light-headedness, fatigue, and vertigo. She was moderately dysmetric, diffusely hyperreflexic, and dysarthric in the bilateral upper and lower extremities. Her gait was wide-based. She had dysarthria and nystagmus on horizontal gaze bilaterally. Magnetic resonance imaging showed an extensive area of increased T2/fluid-attenuated inversion recovery signal in the brain stem, enhancement in the pons and midbrain, and thickening of the pituitary stalk. Positron emission tomography/computed tomography (PET/CT) and whole-body technetium Tc99m bone scintigraphy showed intense symmetrical radiotracer uptake in the distal femur and tibia bilaterally, which was biopsied. Immunohistochemistry was negative for BRAF V600E, but genomic sequencing revealed the mutation. The patient received combination therapy with dabrafenib and trametinib. Her nystagmus, dysarthria, dysmetria, and gait improved remarkably. Subsequent PET/CT and magnetic resonance imaging showed complete resolution of all radiographic evidence of disease. In this case report, we demonstrate the success of a combination therapy with dabrafenib and trametinib.

Analysis of Tissue and Circulating Tumor DNA by Next-Generation Sequencing of Hepatocellular Carcinoma: Implications for Targeted Therapeutics

Hepatocellular carcinoma (HCC) has limited treatment options. Molecular analysis of its mutational landscape may enable the identification of novel therapies. However, biopsy is not routinely performed in HCC. The utility of analyzing cell-free circulating tumor DNA (ctDNA) by next-generation sequencing (NGS) is not established. We performed 32 ctDNA NGS analyses on 26 patients; 10 of these patients had tissue NGS (236 to 626 genes). ctDNA was evaluated using an assay that detects single nucleotide variants, amplifications, fusions, and specific insertion/deletion alterations in 54 to 70 genes. The ctDNA demonstrated that 23 of 26 patients (88.5%) had ≥1 characterized alteration, and all these individuals had ≥1 potentially actionable alteration. The most frequently mutated gene was TP53 (16 of 26 patients, 61.5%). There were 47 unique characterized molecular alterations among 18 total gene alterations [variants of unknown significance (VUS) excluded)]. ctDNA and tissue NGS frequently showed different profiles, perhaps due to length of time between tissue and blood samples [median = 370 days (range, 29 to 876 days)]. Serial ctDNA evaluation in an illustrative patient treated with capecitabine demonstrated emergence of a new TP53 alteration after progression. In conclusion, ctDNA profiling is feasible in advanced HCC, and serial assessment using ctDNA NGS can reveal genomic changes with time. NGS of ctDNA provides a minimally invasive alternative for identifying potentially actionable gene alterations and potential molecular targeted therapies. Dynamic changes in molecular portfolio associated with therapeutic pressure in difficult-to-biopsy patients can be observed. Mol Cancer Ther; 17(5); 1114-22. ©2018 AACR.

Model based analysis of the heterogeneity in the tumour size dynamics differentiates vemurafenib, dabrafenib and trametinib in metastatic melanoma

PURPOSE

Explore the heterogeneity in dynamics of tumour response to vemurafenib, dabrafenib and trametinib using routinely collected clinical trial imaging data.

METHODS

Time-series imaging data from the phase III studies of vemurafenib, dabrafenib and trametinib were collected through a data repository. A mathematical model based on basic mechanisms of tumour growth was placed within a statistical modelling framework to analyse the data.

RESULTS

The analysis revealed: (1) existence of homogeneity in drug response and resistance development within a patient; (2) tumour shrinkage rate does not relate to rate of resistance development; (3) vemurafenib and dabrafenib, two BRAF inhibitors, have different variability in tumour shrinkage rates.

CONCLUSIONS

Overall these results show how analysis of the dynamics of individual lesions can shed light on the within and between patient differences in tumour shrinkage and resistance rates, which could be used to gain a macroscopic understanding of tumour heterogeneity.

A cell based, high throughput assay for quantitative analysis of Hedgehog pathway activation using a Smoothened activation sensor

The Hedgehog (Hh) signalling cascade plays an important role in development and disease. In the absence of Hh ligand, activity of the key signal transducer Smoothened (Smo) is downregulated by the Hh receptor Patched (Ptc). However, the mechanisms underlying this inhibition, and especially its release upon ligand stimulation, are still poorly understood, in part because tools for following Smo activation at the subcellular level were long lacking. To address this deficit we have developed a high throughput cell culture assay based on a fluorescent sensor for Drosophila Smo activation. We have screened a small molecule inhibitor library, and observed increased Smo sensor fluorescence with compounds aimed at two major target groups, the MAPK signalling cascade and polo and aurora kinases. Biochemical validation for selected inhibitors (dobrafenib, tak-733, volasertib) confirmed the screen results and revealed differences in the mode of Smo activation. Furthermore, monitoring Smo activation at the single cell level indicated that individual cells exhibit different threshold responses to Hh stimulation, which may be mechanistically relevant for the formation of graded Hh responses. Together, these results thus provide proof of principle that our assay may become a valuable tool for dissecting the cell biological basis of Hh pathway activation.

Safety, tolerability, and pharmacokinetic profile of dabrafenib in Japanese patients with BRAF V600 mutation-positive solid tumors: a phase 1 study

Background Dabrafenib is a BRAF inhibitor that has demonstrated clinical activity with a good tolerability profile in patients with BRAF ^V600E mutated metastatic melanoma. This study evaluated the safety and tolerability, pharmacokinetics and preliminary efficacy of dabrafenib in Japanese patients. Methods This phase I, open-label, dose escalation study was conducted in 12 Japanese patients with BRAF ^V600 mutation positive solid tumours. Primary endpoint was safety, assessed by monitoring and recording of all adverse events (AEs), serious AEs, drug-related AEs; secondary endpoints were pharmacokinetic profiles and efficacy measured by tumour response. This study is registered with ClinicalTrials.gov, number NCT01582997. Results Of the 12 patients enrolled, 3 each received 75 mg and 100 mg dabrafenib while 6 received 150 mg dabrafenib twice daily orally. Melanoma and thyroid cancer were the primary tumours reported in 11 (92%) and 1 (8%) patients respectively. Most AEs were grade 1 or 2 and considered related to study treatment. Most common AEs reported in the 12 patients were alopecia in 7 (58%); pyrexia, arthralgia and leukopenia in 6 (50%) each, hyperkeratosis and nausea in 4 (33%) each. Partial response as best overall response was reported in 7 of 12 (58%) patients and in 6 (55%) with malignant melanoma. No dose-limiting toxicity (DLTs) were reported during the DLT evaluation periods. Conclusions Dabrafenib was well tolerated and rapidly absorbed administered as single- or multiple dose. Comparable safety and pharmacokinetic profiles were observed compared with non-Japanese patients. Dabrafenib has promising clinical activity in Japanese patients with BRAF mutated malignant melanoma.

A guanine derivative as a new MEK inhibitor produced by Streptomyces sp. MK63-43F2

Mitogen-activated protein kinase (MAPK) pathways that direct cellular responses are involved in various biological processes; the RAS-RAF-MEK-ERK pathway is one of the most important MAPK pathways. It is frequently activated in human malignant tumors such as melanomas, thyroid tumors and colorectal carcinomas. Therefore, targeting this pathway has been considered an attractive strategy for new anticancer drugs. In particular, MEK is a promising target because it is a kinase that directly phosphorylates ERK. We performed a screening to discover new MEK inhibitors, and found a guanine derivative produced by Streptomyces sp. MK63-43F2. This guanine derivative was identified to be 2-amino-4-methoxy-5-cyanopyrrolo[2,3-d]pyrimidine (1) through spectroscopic analysis. Compound 1 inhibited MEK1 kinase activity in an ATP-dependent manner and suppressed the phosphorylation of ERK in cancer cells and cell proliferation. Therefore, 1 might be a potent lead compound for new MEK inhibitors.The Journal of Antibiotics advance online publication, 6 September 2017; doi:10.1038/ja.2017.100.

Genetic Mutations and Epigenetic Modifications: Driving Cancer and Informing Precision Medicine

Cancer treatment is undergoing a significant revolution from "one-size-fits-all" cytotoxic therapies to tailored approaches that precisely target molecular alterations. Precision strategies for drug development and patient stratification, based on the molecular features of tumors, are the next logical step in a long history of approaches to cancer therapy. In this review, we discuss the history of cancer treatment from generic natural extracts and radical surgical procedures to site-specific and combinatorial treatment regimens, which have incrementally improved patient outcomes. We discuss the related contributions of genetics and epigenetics to cancer progression and the response to targeted therapies and identify challenges and opportunities for the success of precision medicine. The identification of patients who will benefit from targeted therapies is more complex than simply identifying patients whose tumors harbour the targeted aberration, and intratumoral heterogeneity makes it difficult to determine if a precision therapy is successful during treatment. This heterogeneity enables tumors to develop resistance to targeted approaches; therefore, the rational combination of therapeutic agents will limit the threat of acquired resistance to therapeutic success. By incorporating the view of malignant transformation modulated by networks of genetic and epigenetic interactions, molecular strategies will enable precision medicine for effective treatment across cancer subtypes.

Identification of the Serine Biosynthesis Pathway as a Critical Component of BRAF Inhibitor Resistance of Melanoma, Pancreatic, and Non-Small Cell Lung Cancer Cells

Metastatic melanoma cells commonly acquire resistance to BRAF V600E inhibitors (BRAFi). In this study, we identified serine biosynthesis as a critical mechanism of resistance. Proteomic assays revealed differential protein expression of serine biosynthetic enzymes PHGDH, PSPH, and PSAT1 following vemurafenib (BRAFi) treatment in sensitive versus acquired resistant melanoma cells. Ablation of PHGDH via siRNA sensitized acquired resistant cells to vemurafenib. Inhibiting the folate cycle, directly downstream of serine synthesis, with methotrexate also displayed similar sensitization. Using the DNA-damaging drug gemcitabine, we show that gemcitabine pretreatment sensitized resistant melanoma cells to BRAFis vemurafenib and dabrafenib. We extended our findings to BRAF WT tumor cell lines that are intrinsically resistant to vemurafenib and dabrafenib. Pretreatment of pancreatic cancer and non-small cell lung cancer cell lines with sublethal doses of 50 and 5 nmol/L of gemcitabine, respectively, enhanced killing by both vemurafenib and dabrafenib. The novel aspects of this study are the direct identification of serine biosynthesis as a critical mechanism of BRAF V600E inhibitor resistance and the first successful example of using gemcitabine + BRAFis in combination to kill previously drug-resistant cancer cells, creating the translational potential of pretreatment with gemcitabine prior to BRAFi treatment of tumor cells to reverse resistance within the mutational profile and the WT. Mol Cancer Ther; 16(8); 1596-609. ©2017 AACR.

Androgen receptor promotes melanoma metastasis via altering the miRNA-539-3p/USP13/MITF/AXL signals

Early studies demonstrated that male melanoma patients have worse survival than female patients, yet the detailed mechanisms for this gender difference remain unclear. We analyzed around 100 cases of human melanoma and found that androgen receptor (AR) positive melanoma patients have worse survival outcomes compared with AR-negative melanoma patients. Here we report that AR can have positive roles to increase melanoma cell invasion in multiple cell lines in vitro and a mouse model in vivo. Mechanism dissection suggest that AR increases melanoma cell invasion via modulating the MITF-AXL signals via altering the miRNA-539-3p/USP13 signaling to increase MITF protein degradation through a reduction of de-ubiquitination. Restoring MITF can reverse AR-enhanced melanoma cell invasion. Together, our results demonstrate that AR can promote melanoma metastasis via altering the miRNA-539-3p/USP13/MITF/AXL signal and targeting this newly identified signal with AR degradation enhancer ASC-J9 may help us to better suppress the melanoma metastasis.

What links BRAF to the heart function? New insights from the cardiotoxicity of BRAF inhibitors in cancer treatment

The RAS-related signalling cascade has a fundamental role in cell. It activates differentiation and survival. It is particularly important one of its molecules, B-RAF. B-RAF has been a central point for research, especially in melanoma. Indeed, it lacked effective therapeutic weapons since the early years of its study. Molecules targeting B-RAF have been developed. Nowadays, two classes of molecules are approved by FDA. Multi-target molecules, such as Sorafenib and Regorafenib, and selective molecules, such as Vemurafenib and Dabrafenib. Many other molecules are still under investigation. Most of them are studied in phase 1 trials. Clinical studies correlate B-RAF inhibitors and QT prolongation. Though this cardiovascular side effect is not common using these drugs, it must be noticed early and recognize its signals. Indeed, Oncologists and Cardiologists should work in cooperation to prevent lethal events, such as fatal arrhythmias or sudden cardiac death. These events could originate from an uncontrolled QT prolongation.

A case of recurrent bilateral uveitis independently associated with dabrafenib and pembrolizumab therapy

Purpose

To report the case of an adult female who presented on different occasions with recurrent uveitis provoked by initiating therapy of two recently approved agents, dabrafenib and pembrolizumab, for treatment of metastatic melanoma.

Observations

A 61 year old female presented with bilateral anterior uveitis after initiating therapy with dabrafenib for advanced metastatic melanoma. Her symptoms resolved and exam improved with oral and topical steroid therapy. Months later, she was started on pembrolizumab and transitioned off dabrafenib. Within days of starting pembrolizumab, she developed recurrent bilateral uveitis. This responded to escalating doses of topical and oral corticosteroid therapy and resolved following discontinuation of pembrolizumab. Nine months later, our patient received her third dose of pembrolizumab due to further progression of melanoma and within three days developed blurry vision, photophobia and subsequent ophthalmologic exam demonstrated bilateral panuveitis.

Conclusions and importance

Dabrafenib and pembrolizumab therapy have both previously been associated with uveitis. Here, we document a case of a woman who developed acute uveitis in response to beginning therapy with dabrafenib and then later developed acute uveitis soon after initiating pembrolizumab. To our knowledge, this is the first time this uncommon side-effect has been reported in the same patient after receiving sequential targeted agents and checkpoint inhibitors.

Long-term drug costs per life-month gained associated with first-line treatments for unresectable or metastatic melanoma

BACKGROUND

For unresectable or metastatic melanoma, first-line ipilimumab has demonstrated long-term survival benefits over a 7-year period. First-line treatment with BRAF inhibitors has demonstrated efficacy in clinical trials with up to 3 years of follow-up. The long-term comparative efficacy and costs of ipilimumab and BRAF inhibitors are unknown.

METHODS

Patient-level data from 12 clinical studies for ipilimumab were used. Survival data were extracted from included clinical trials for BRAF inhibitors based on a systematic literature review. Different parametric survival models, including exponential, Gompertz, log-normal, and Weibull models, were used to fit reported overall survival (OS) data and to project long-term survival for BRAF inhibitors. Survival benefits were measured in terms of total life-months gained as calculated by the area under the curve of OS Kaplan-Meier curves for the observed ipilimumab data and projected BRAF inhibitor data. Total life-months gained and cumulative costs per life-month gained were compared between ipilimumab and BRAF inhibitors.

RESULTS

The systematic literature review identified six randomized-controlled trials of BRAF inhibitors for subsequent analyses. With 7-year follow-up, ipilimumab was associated with a total of 28.5 life-months gained. Based on the Weibull model, the extrapolated total life-months gained for BRAF inhibitors were 26.5 months for dabrafenib, 21.3 months for trametinib, 14.3 months for vemurafenib, and 24.6 months for dabrafenib + trametinib. In sensitivity analyses, extrapolated total life-months gained varied across the three other models, ranging from 13.7 to 36.8 months across therapies. Cumulative costs per life-month gained with ipilimumab decreased steadily over time, while the costs remained constant for BRAF inhibitors due to continuous dosing. By year 3, cumulative costs per life-month gained were the lowest with ipilimumab; by year 7, the costs were $4281 for ipilimumab, compared with $8920 for dabrafenib, $10,211 for trametinib, $11,002 for vemurafenib, and $19,132 for the dabrafenib + trametinib combination therapy.

CONCLUSIONS

Ipilimumab was associated with a better long-term cost-per-life month compared to BRAF agents. Long-term extrapolation of survival with BRAF agents was uncertain, and showed no evidence of prolonged survival compared to ipilimumab.

Competitive allele-specific TaqMan PCR (Cast-PCR) is a sensitive, specific and fast method for BRAF V600 mutation detection in Melanoma patients

BRAF codon 600 mutation testing of melanoma patients is mandatory for the choice of the most appropriate therapy in the clinical setting. Competitive allele specific TaqMan PCR (Cast-PCR) technology allows not only the selective amplification of minor alleles, but it also blocks the amplification of non-mutant allele. We genotyped codon 600 of the BRAF gene in 54 patients’ samples by Cast-PCR and bidirectional direct sequence analysis. All the mutations detected by sequencing were also identified by Cast-PCR. In addition, Cast-PCR assay detected four samples carrying mutations and was able to clearly identify two mutations of uncertain interpretation by Sanger sequencing. The limit of detection of Cast-PCR was evaluated by constructing dilution curves of BRAF^V600E and BRAF^V600K mutated clinical samples mixed with a not-mutated specimens. Both mutations could be detected until a 1:100 mutated/not mutated ratio. Cloning and sequencing of the clones was used to confirm mutations on representative discrepant cases. Cast PCR performances were not affected by intratumour heterogeneity, and less affected by melanin content. Our results indicate that Cast-PCR is a reliable diagnostic tool for the identification of melanoma patients as eligible to be treated with TKIs and might be implemented in the clinical setting as elective screening method.

Stamping out RAF and MEK1/2 to inhibit the ERK1/2 pathway: an emerging threat to anticancer therapy

The RAS-RAF-MEK1/2-ERK1/2 pathway is a key signal transduction pathway in the cells. Critically, it remains constitutively active in approximately 30% of human cancers, having key roles in cancer development, maintenance and progression, while being responsible for poorer prognosis and drug resistance. Consequently, the inhibition of this pathway has been the subject of intense research for >25 years. The advent of better patient screening techniques has increasingly shown that upstream regulators like RAS and RAF remain persistently mutated in many cancer types. These gain-of-function mutations, such as KRAS-4B(G12V/G13D/Q61K), NRAS(Q61L/Q61R) or BRAF(V600E), lead to tremendous increase in their activities, resulting in constitutively active extracellular signal-regulated kinase 1/2 (ERK1/2). They were not efficiently targeted by the first-generation inhibitors such as Lonafarnib or Sorafenib, which were essentially broad spectrum inhibitors targeting pan-RAS and pan-RAF, respectively. This triggered the development of the second-generation inhibitors selective against the mutated proteins. Second generation inhibitors such as Vemurafenib (Zelboraf) and Dabrafenib (Tafinlar) targeting BRAF(V600E), Trametinib (Mekinist) targeting MEK1/2 and the first generation pan-RAF inhibitor Sorafenib (Nexavar) have already been approved for treating renal, hepatocellular, thyroid cancers and BRAF(V600E/K) harboring metastatic melanoma. Others against RAF and MEK1/2 are presently undergoing clinical trials. Their success would depend on the better understanding of the acquired resistance mechanisms to these drugs in the cancer cells and the identification of predictive biomarkers for the proper administration of suitable inhibitor(s).

Dabrafenib and its use in the treatment of metastatic melanoma

Approximately 50% of melanomas have mutations in the gene encoding BRAF. In recent years, new targeted therapies have transformed the landscape of metastatic melanoma treatment. Dabrafenib, a potent kinase inhibitor of mutated BRAF, has been showed to have high response rates with a rapid onset of response, as well as improved overall and progression-free survival when compared with chemotherapy. Dabrafenib in combination with trametinib, a MEK inhibitor, has demonstrated higher responses and improved clinical efficacy compared with monotherapy. Toxicity is distinct compared with chemotherapy but manageable. This article summarizes the pharmacology, key clinical trial data as well as practical experience with dabrafenib in clinical practice, and future directions.

Novel Approaches to Treatment of Advanced Melanoma: A Review on Targeted Therapy and Immunotherapy

The incidence of malignant melanoma is increasing. The majority of patients are diagnosed in early stages when the disease is highly curable. However, the more advanced or metastatic cases have always been a challenge for clinicians. The poor prognosis for patients with melanoma is now changing as numerous of promising approaches have appeared recently. The discovery of aberrations of pathways responsible for intracellular signal transduction allowed us to introduce agents specifically targeting the mutated cascades. Numerous clinical studies have been conducted to improve effectiveness of melanoma treatment. From 2011 until now, the U.S. FDA has approved seven novel agents, such as BRAF-inhibitors (vemurafenib 2011, dabrafenib 2013), MEK-inhibitors (trametinib 2013), anti-PD1 antibodies (nivolumab 2014, pembrolizumab 2014), anti-CTLA-4 antibody (ipilimumab 2011), or peginterferon-alfa-2b (2011) intended to be used in most advanced cases of melanoma. Nevertheless, clinicians continue working on new possible methods of treatment as resistance to the novel drugs is a commonly observed problem. This paper is based on latest data published until the end of January 2015.

Severe bilateral panuveitis during melanoma treatment by Dabrafenib and Trametinib

BACKGROUND

We report a case of severe bilateral panuveitis during melanoma therapy with a combination of Dabrafenib, a B-raf (BRAF) inhibitor, and Trametinib, a mitogen/extracellular signal-regulated kinase (MEK) inhibitor. Both of these drugs are effectors in the mitogen-activated protein kinase (MAPK) pathway, which plays an important role in the physiopathology of melanoma. Dabrafenib and Trametinib have shown improved survival of patients with metastatic melanoma but they have also been associated with the development of uveitis.

FINDINGS

Our patient was a 55-year-old woman with metastatic melanoma who presented with sudden onset of bilateral painless visual loss. She had been treated with Dabrafenib and Trametinib. Trametinib was discontinued at the onset of symptoms but there was no improvement. Ophthalmological examination revealed severe bilateral non-granulomatous panuveitis, with choroidal thickening, chorio-retinal folds, and multiple serous retinal detachments (SRDs). Topical corticosteroid treatment was initiated, and Dabrafenib was discontinued. A good response was obtained with a recovery of visual acuity of 20/25 on both eyes and an almost complete resolution of the SRDs.

CONCLUSIONS

This case highly suggests that MAPK pathway inhibition can lead to severe uveitis. Dabrafenib and Trametinib could have both played a role in inducing the disease. Further studies are needed to evaluate the possible role of the combination of these drugs in inducing uveitis and SRD.

Toward precision medicine in glioblastoma: the promise and the challenges

Integrated sequencing strategies have provided a broader understanding of the genomic landscape and molecular classifications of multiple cancer types and have identified various therapeutic opportunities across cancer subsets. Despite pivotal advances in the characterization of genomic alterations in glioblastoma, targeted agents have shown minimal efficacy in clinical trials to date, and patient survival remains poor. In this review, we highlight potential reasons why targeting single alterations has yielded limited clinical efficacy in glioblastoma, focusing on issues of tumor heterogeneity and pharmacokinetic failure. We outline strategies to address these challenges in applying precision medicine to glioblastoma and the rationale for applying targeted combination therapy approaches that match genomic alterations with compounds accessible to the central nervous system.