The Promise of Molecularly Targeted and Immunotherapy for Advanced Melanoma

Children's Oncology Group's 2023 blueprint for research: Rare tumors

The Children's Oncology Group (COG) Rare Tumor Committee includes the Infrequent Tumor and Retinoblastoma subcommittees, encompassing a wide range of extracranial solid tumors that do not fall within another COG disease committee. Current therapeutic trial development focuses on nasopharyngeal carcinoma, adrenocortical carcinoma, pleuropulmonary blastoma, colorectal carcinoma, melanoma, and thyroid carcinoma. Given the rarity of these tumors, novel strategies and international collaborative efforts are necessary to advance research and improve outcomes.

Nanodelivery systems for cutaneous melanoma treatment

Cutaneous melanoma (CM) is a multifactorial disease whose treatment still presents challenges: the rapid progression to advanced CM, which leads to frequent recurrences even after surgical excision and, notably, the low response rates and resistance to the available therapies, particularly in the case of unresectable metastatic CM. Thereby, alternative innovative therapeutic approaches for CM continue to be searched. In this review we discuss relevant preclinical research studies, and provide a broad-brush analysis of patents and clinical trials which involve the application of nanotechnology-based delivery systems in CM therapy. Nanodelivery systems have been developed for the delivery of anticancer biomolecules to CM, which can be administered by different routes. Overall, nanosystems could promote technological advances in several therapeutic modalities and can be used in combinatorial therapies. Nevertheless, the results of these preclinical studies have not been translated to clinical applications. Thus, concerted and collaborative research studies involving basic, applied, translational, and clinical scientists need to be performed to allow the development of effective and safe nanomedicines to treat CM.

The influence of the blood-brain barrier in the treatment of brain tumours

Brain tumours have a poor prognosis and lack effective treatments. The blood-brain barrier (BBB) represents a major hurdle to drug delivery to brain tumours. In some locations in the tumour, the BBB may be disrupted to form the blood-brain tumour barrier (BBTB). This leaky BBTB enables diagnosis of brain tumours by contrast enhanced magnetic resonance imaging; however, this disruption is heterogeneous throughout the tumour. Thus, relying on the disrupted BBTB for achieving effective drug concentrations in brain tumours has met with little clinical success. Because of this, it would be beneficial to design drugs and drug delivery strategies to overcome the 'normal' BBB to effectively treat the brain tumours. In this review, we discuss the role of BBB/BBTB in brain tumour diagnosis and treatment highlighting the heterogeneity of the BBTB. We also discuss various strategies to improve drug delivery across the BBB/BBTB to treat both primary and metastatic brain tumours. Recognizing that the BBB represents a critical determinant of drug efficacy in central nervous system tumours will allow a more rapid translation from basic science to clinical application. A more complete understanding of the factors, such as BBB-limited drug delivery, that have hindered progress in treating both primary and metastatic brain tumours, is necessary to develop more effective therapies.

Identification of differentially expressed metastatic genes and their signatures to predict the overall survival of uveal melanoma patients by bioinformatics analysis

AIM

To identify metastatic genes and miRNAs and to investigate the metastatic mechanism of uveal melanoma (UVM).

METHODS

GSE27831, GSE39717, and GSE73652 gene expression profiles were downloaded from the Gene Expression Omnibus (GEO) database, and the limma R package was used to identify differentially expressed genes (DEGs). Gene Ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed using the DAVID online tool. A comprehensive list of interacting DEGs was constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database and Cytoscape software. The Cytoscape MCODE plug-in was used to identify clustered sub-networks and modules of hub genes from the protein-protein interaction network. GEPIA online software was used for survival analysis of UVM patients (n=80) from the The Cancer Genome Atlas (TCGA) cohort. OncomiR online software was used to find that the miRNAs were associated with UVM prognosis from the TCGA cohort. TargetScan Human 7.2 software was then used to identify the miRNAs targeting the genes.

RESULTS

There were 1600 up-regulated genes and 1399 down-regulated genes. The up-regulated genes were mainly involved in protein translation in the cytosol, whereas the down-regulated genes were correlated with extracellular matrix organization and cell adhesion in the extracellular space. Among the 2999 DEGs, five genes, Znf391, Mrps11, Htra3, Sulf2, and Smarcd3 were potential predictors of UVM prognosis. Otherwise, three miRNAs, hsa-miR-509-3-5p, hsa-miR-513a-5p, and hsa-miR-1269a were associated with UVM prognosis.

CONCLUSION

After analyzing the metastasis-related enriched terms and signaling pathways, the up-regulated DEGs are mainly involved in protein synthesis and cell proliferation by ribosome and mitogen-activated protein kinase (MAPK) pathways. However, the down-regulated DEGs are mainly involved in processes that reduced cell-cell adhesion and promoted cell migration in the extracellular matrix through PI3K-Akt signaling pathway, focal adhesion, and extracellular matrix-receptor interactions. Bioinformatics and interaction analysis may provide new insights on the events leading up to the development and progression of UVM.

Brain Metastases Unresponsive to Immunotherapy Detected by 18F-FDG-PET/CT in a Patient with Melanoma

Recently, newer therapies such as immunotherapy have been increasingly used in the treatment of several tumors, including advanced melanoma. In particular, several studies showed that the combination of ipilimumab, an anti-Cytotoxic T-lymphocyte Associated Protein 4 (CTLA-4) monoclonal antibody and nivolumab, an anti-Programmed Death 1 (PD-1) monoclonal antibody, leads to improved survival in patients with metastatic melanoma. Despite that, immunotherapeutic agents may not reach therapeutic concentration in the brain due to the blood–brain barrier. We report the case of a 50-year-old man with advanced melanoma who underwent whole-body 18F-FDG-PET/CT before and after treatment with immunotherapy showing resistant brain metastases confirmed by subsequent MRI of the brain. Moreover, 18F-FDG-PET/CT was able to detect an immune-related adverse event such as enterocolitis that contributed to the worsening of patient conditions. This case shows how a whole-body methodology such as 18F-FDG-PET/CT can be useful in identifying melanoma cancer patients unresponsive to immunotherapy that may benefit from traditional palliative therapy in the effort to improve their quality of life.

Low expression of pro-apoptotic proteins Bax, Bak and Smac indicates prolonged progression-free survival in chemotherapy-treated metastatic melanoma

Despite the introduction of novel targeted therapies, chemotherapy still remains the primary treatment for metastatic melanoma in poorly funded healthcare environments or in case of disease relapse, with no reliable molecular markers for progression-free survival (PFS) available. As chemotherapy primarily eliminates cancer cells by apoptosis, we here evaluated if the expression of key apoptosis regulators (Bax, Bak, Bcl-2, Bcl-xL, Smac, Procaspase-9, Apaf-1, Procaspase-3 and XIAP) allows prognosticating PFS in stage III/IV melanoma patients. Following antibody validation, marker expression was determined by automated and manual scoring of immunohistochemically stained tissue microarrays (TMAs) constructed from treatment-naive metastatic melanoma biopsies. Interestingly and counter-intuitively, low expression of the pro-apoptotic proteins Bax, Bak and Smac indicated better prognosis (log-rank p < 0.0001, p = 0.0301 and p = 0.0227 for automated and p = 0.0422, p = 0.0410 and p = 0.0073 for manual scoring). These findings were independently validated in the cancer genome atlas (TCGA) metastatic melanoma cohort (TCGA-SKCM) at transcript level (log-rank p = 0.0004, p = 0.0104 and p = 0.0377). Taking expression heterogeneity between the markers in individual tumour samples into account allowed defining combinatorial Bax, Bak, Smac signatures that were associated with significantly increased PFS (p = 0.0002 and p = 0.0028 at protein and transcript level, respectively). Furthermore, combined low expression of Bax, Bak and Smac allowed predicting prolonged PFS (> 12 months) on a case-by-case basis (area under the receiver operating characteristic curve (ROC AUC) = 0.79). Taken together, our results therefore suggest that Bax, Bak and Smac jointly define a signature with potential clinical utility in chemotherapy-treated metastatic melanoma.

A novel chalcone derivative has antitumor activity in melanoma by inducing DNA damage through the upregulation of ROS products

Background

Melanoma is one of the most aggressive tumors with the remarkable characteristic of resistance to traditional chemotherapy and radiotherapy. Although targeted therapy and immunotherapy benefit advanced melanoma patient treatment, BRAFi (BRAF inhibitor) resistance and the lower response rates or severe side effects of immunotherapy have been observed, therefore, it is necessary to develop novel inhibitors for melanoma treatment.

Methods

We detected the cell proliferation of lj-1-59 in different melanoma cells by CCK 8 and colony formation assay. To further explore the mechanisms of lj-1-59 in melanoma, we performed RNA sequencing to discover the pathway of differential gene enrichment. Western blot and Q-RT-PCR were confirmed to study the function of lj-1-59 in melanoma.

Results

We found that lj-1-59 inhibits melanoma cell proliferation in vitro and in vivo, induces cell cycle arrest at the G2/M phase and promotes apoptosis in melanoma cell lines. Furthermore, RNA-Seq was performed to study alterations in gene expression profiles after treatment with lj-1-59 in melanoma cells, revealing that this compound regulates various pathways, such as DNA replication, P53, apoptosis and the cell cycle. Additionally, we validated the effect of lj-1-59 on key gene expression alterations by Q-RT-PCR. Our findings showed that lj-1-59 significantly increases ROS (reactive oxygen species) products, leading to DNA toxicity in melanoma cell lines. Moreover, lj-1-59 increases ROS levels in BRAFi -resistant melanoma cells, leading to DNA damage, which caused G2/M phase arrest and apoptosis.

Conclusions

Taken together, we found that lj-1-59 treatment inhibits melanoma cell growth by inducing apoptosis and DNA damage through increased ROS levels, suggesting that this compound is a potential therapeutic drug for melanoma treatment.

Bevacizumab treatment of meningeal melanoma metastases

Background

Melanoma patients with metastatic growth in the meninges have poor prognosis and few treatment options. Although treatment with BRAF inhibitors or immune checkpoint inhibitors has provided promising results, most patients with advanced melanoma are resistant to these treatments and develop severe side effects. Novel treatment strategies are needed for patients with meningeal melanoma metastases, and the potential of antiangiogenic therapy was investigated in this preclinical study.

Methods

Two GFP-transfected melanoma models (A-07 and D-12) differing substantially in VEGF-A expression were included in the study, and the anti-VEGF-A antibody bevacizumab was used as therapeutic agent. Meningeal metastases were initiated in BALB/c nu/nu mice by intracranial inoculation of melanoma cells, and bevacizumab treatment was given twice a week in i.p. doses of 10 mg/kg until the mice became moribund. Therapeutic effects were evaluated by determining tumor host survival time, assessing tumor growth and angiogenic activity by quantitative analyses of histological preparations, and measuring the expression of angiogenesis-related genes by quantitative PCR.

Results

Meningeal A-07 melanomas showed higher expression of VEGF-A than meningeal D-12 melanomas, whereas the expression of ANGPT2 and IL8, two important angiogenesis drivers in melanoma, was much higher in D-12 than in A-07 tumors. Bevacizumab treatment inhibited tumor angiogenesis and prolonged host survival in mice with A-07 tumors but not in mice with D-12 tumors. Meningeal A-07 tumors in bevacizumab-treated mice compensated for the reduced VEGF-A activity by up-regulating a large number of angiogenesis-related genes, including ANGPT2 and its receptors TIE1 and TIE2. Melanoma cells migrated from meningeal tumors into the cerebrum, where they initiated metastatic growth by vessel co-option. In the A-07 model, the density of cerebral micrometastases was higher in bevacizumab-treated than in untreated mice, either because bevacizumab treatment increased mouse survival or induced increased tumor gene expression.

Conclusions

The development of antiangiogenic strategies for the treatment of meningeal melanoma metastases is a challenging task because the outcome of treatment will depend on the angiogenic signature of the tumor tissue, treatment-induced alterations of the angiogenic signature, and the treatment sensitivity of metastatic lesions in other intracranial sites.

Efficacy of melanoma patients treated with PD-1 inhibitors: Protocol for an overview, and a network meta-analysis of randomized controlled trials

BACKGROUND

Melanoma is a malignant tumor of melanocytes that produces pigments and can occur in the whole body. It is characterized by strong invasiveness, high metastasis rate and poor prognosis, and brings heavy burden to patients and society. In order to find the most effective and safe treatment measures, in this study, a network meta-analysis (NMA) for randomized controlled trials (RCTs) of advanced melanoma treated with PD-1 inhibitors will be conducted based on the existing systematic reviews (SRs) of PD-1 inhibitor in the treatment of advanced melanoma.

METHODS

PubMed, EMBASE, Web of Science and the Cochrane Library were searched on December 18, 2018 to obtain systematic reviews of PD-1 inhibitor in the treatment of advanced melanoma. Assessing the Methodological Quality of Systematic Reviews (AMSTAR2) will be used to assess the methodological quality of systematic reviews, Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach will be applied to evaluate the evidence quality of outcome measures, and the Cochrane's risk of bias tool will be utilized to appraise risks of bias of each embedded RCTs. And the outcomes are overall survival (OS), progression-free survival (PFS) and objective response rate (ORR). Hazard ratio (HR) or odds ratio (OR) with their 95% confidence interval (CI) were used to synthesize dichotomous outcomes, while the mean difference (MD) for the continuous variables. R3.5.1 will be used to create a network evidence map for direct and indirect comparative analysis.

RESULTS

This study will provide a comprehensive summary of the current evidences related to the efficacy and safety of PD-1 inhibitor in advanced melanoma.

CONCLUSION

Our findings will be useful to assist clinicians make reasonable decisions to the treatment of advanced melanoma.

ETHICS AND COMMUNICATION

It is unnecessary for this NMA to acquire an ethical approval, because it is based on published researches.

PROSPERO REGISTRATION NUMBER

CRD42019120017.

Patient preferences for treatment of metastatic melanoma

AIM

To investigate patient preferences for clinical attributes of first-line metastatic melanoma treatments.

MATERIALS & METHODS

A discrete-choice experiment and best-worst scaling exercise were used to assess relative preferences for treatment attributes.

RESULTS

The 200 survey respondents had distinct preferences. Avoiding a 30% risk of colitis or hormone gland problems and avoiding severe fever were more important to respondents than avoiding a 20% risk of extreme sun sensitivity (p < 0.05). Patients preferred taking pills to receiving intravenous infusions in a clinic. When attributes were combined, approximately 85% of respondents preferred a risk profile similar to targeted therapy over a profile similar to immunotherapy, holding efficacy constant.

CONCLUSION

Taking patient preferences into account can help patients get the full benefit from metastatic melanoma therapies.

Systemic network analysis identifies XIAP and IκBα as potential drug targets in TRAIL resistant BRAF mutated melanoma

Metastatic melanoma remains a life-threatening disease because most tumors develop resistance to targeted kinase inhibitors thereby regaining tumorigenic capacity. We show the 2nd generation hexavalent TRAIL receptor-targeted agonist IZI1551 to induce pronounced apoptotic cell death in mutBRAF melanoma cells. Aiming to identify molecular changes that may confer IZI1551 resistance we combined Dynamic Bayesian Network modelling with a sophisticated regularization strategy resulting in sparse and context-sensitive networks and show the performance of this strategy in the detection of cell line-specific deregulations of a signalling network. Comparing IZI1551-sensitive to IZI1551-resistant melanoma cells the model accurately and correctly predicted activation of NFκB in concert with upregulation of the anti-apoptotic protein XIAP as the key mediator of IZI1551 resistance. Thus, the incorporation of multiple regularization functions in logical network optimization may provide a promising avenue to assess the effects of drug combinations and to identify responders to selected combination therapies.

STINGel: Controlled release of a cyclic dinucleotide for enhanced cancer immunotherapy

Recent advancements in the field of immunotherapy have yielded encouraging results for the treatment of advanced cancers. Cyclic dinucleotides (CDNs) are a powerful new class of immunotherapy drugs known as STING (Stimulator of Interferon Genes) agonists, currently in clinical trials. However, previous studies of CDNs in murine cancer models have required multiple injections, and improve survival only in relatively nonaggressive tumor models. Therefore, we sought to improve the efficacy of CDN immunotherapy by developing a novel biomaterial we call "STINGel." STINGel is an injectable peptide hydrogel that localizes and provides controlled release of CDN delivery, showing an 8-fold slower release rate compared to a standard collagen hydrogel. The carrier hydrogel is a positively charged, MultiDomain Peptide (MDP) which self-assembles to form a nanofibrous matrix and is easily delivered by syringe. The highly localized delivery of CDN from this nanostructured biomaterial affects the local histological response in a subcutaneous model, and dramatically improves overall survival in a challenging murine model of head and neck cancer compared to CDN alone or CDN delivered from a collagen hydrogel. This study demonstrates the feasibility of biomaterial-based immunotherapy platforms like STINGel as strategies for increasing the efficacy of CDN immunotherapies.

Phenformin-Induced Mitochondrial Dysfunction Sensitizes Hepatocellular Carcinoma for Dual Inhibition of mTOR

Purpose: Hepatocellular carcinoma (HCC) ranks second in cancer mortality and has limited therapeutic options. We recently described the synergistic effect of allosteric and ATP-site competitive inhibitors against the mTOR for the treatment of HCC. However, such inhibitors induce hyperglycemia and increase mitochondrial efficiency. Here we determined whether the mitochondrial complex I inhibitor phenformin could reverse both side effects, impose an energetic stress on cancer cells, and suppress the growth of HCC.Experimental Design: Human HCC cell lines were used in vitro to access the signaling and energetic impact of mTOR inhibitors and phenformin, either alone or in combination. Next, the therapeutic utility of these drugs alone or in combination was investigated preclinically in human orthotopic tumors implanted in mice, by analyzing their impact on the tumor burden and overall survival.Results: We found phenformin caused mitochondrial dysfunction and fragmentation, inducing a compensatory shift to glycolysis. In contrast, dual inhibition of mTOR impaired cell growth and glycolysis, while increasing mitochondrial fusion and efficiency. In a mouse model of human HCC, dual inhibition of mTOR, together with phenformin, was highly efficacious in controlling tumor burden. However, more strikingly, pretreatment with phenformin sensitized tumors to dual inhibition of mTOR, leading to a dramatic improvement in survival.Conclusions: Treatment of HCC cells in vitro with the biguanide phenformin causes a metabolic shift to glycolysis, mitochondrial dysfunction and fragmentation, and dramatically sensitizes orthotopic liver tumors to dual inhibition of mTOR. We therefore propose this therapeutic approach should be tested clinically in HCC. Clin Cancer Res; 24(15); 3767-80. ©2018 AACR.

State of the Art Treatment of Spinal Metastatic Disease

Treatment paradigms for patients with spine metastases have evolved significantly over the past decade. Incorporating stereotactic radiosurgery into these paradigms has been particularly transformative, offering precise delivery of tumoricidal radiation doses with sparing of adjacent tissues. Evidence supports the safety and efficacy of radiosurgery as it currently offers durable local tumor control with low complication rates even for tumors previously considered radioresistant to conventional radiation. The role for surgical intervention remains consistent, but a trend has been observed toward less aggressive, often minimally invasive, techniques. Using modern technologies and improved instrumentation, surgical outcomes continue to improve with reduced morbidity. Additionally, targeted agents such as biologics and checkpoint inhibitors have revolutionized cancer care, improving both local control and patient survivals. These advances have brought forth a need for new prognostication tools and a more critical review of long-term outcomes. The complex nature of current treatment schemes necessitates a multidisciplinary approach including surgeons, medical oncologists, radiation oncologists, interventionalists, and pain specialists. This review recapitulates the current state-of-the-art, evidence-based data on the treatment of spinal metastases, integrating these data into a decision framework, NOMS, which integrates the 4 sentinel decision points in metastatic spine tumors: Neurologic, Oncologic, Mechanical stability, and Systemic disease and medical co-morbidities.

Recovery of Immunoglobulin VJ Recombinations from Pancreatic Cancer Exome Files Strongly Correlates with Reduced Survival

We assessed pancreatic cancer, lymphocyte infiltrates with a computational genomics approach. We took advantage of tumor-specimen exome files available from the cancer genome atlas to mine T- and B-cell immune receptor recombinations, using highly efficient, scripted algorithms established in several previous reports. Surprisingly, the results indicated that pancreatic cancer exomes represent one of the highest level yields for immune receptor recombinations, significantly higher than two comparison cancers used in this study, head and neck and bladder cancer. In particular, pancreatic cancer exomes have very large numbers of immunoglobulin light chain recombinations, both with regard to number of samples characterized by recovery of such recombinations and with regard to numbers of recombination reads per sample. These results were consistent with B-cell biomarkers, which emphasized the Th2 nature of the pancreatic lymphocyte infiltrate. The tumor specimen exomes with B-cell immune receptor recombination reads represented a dramatically poor outcome, a result not detected with either the head and neck or bladder cancer datasets. The results presented here support the potential value of immunotherapies designed to engineer a Th2 to Th1 shift in treating certain forms of pancreatic cancer.

Brain Distribution of a Novel MEK Inhibitor E6201: Implications in the Treatment of Melanoma Brain Metastases

Clinically meaningful efficacy in the treatment of brain tumors, including melanoma brain metastases (MBM), requires selection of a potent inhibitor against a suitable target, and adequate drug distribution to target sites in the brain. Deregulated constitutive signaling of mitogen-activated protein kinase (MAPK) pathway has been frequently observed in melanoma, and mitogen-activated protein/extracellular signal-regulated kinase (MEK) has been identified to be an important target. E6201 is a potent synthetic small-molecule MEK inhibitor. The purpose of this study was to evaluate brain distribution of E6201, and examine the impact of active efflux transport at the blood-brain barrier on the central nervous system (CNS) exposure of E6201. In vitro studies utilizing transfected Madin-Darby canine kidney II (MDCKII) cells indicate that E6201 is not a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp). In vivo studies also suggest a minimal involvement of P-gp and Bcrp in E6201's brain distribution. The total concentrations in brain were higher than in plasma, resulting in a brain-to-plasma AUC ratio (Kp) of 2.66 in wild-type mice. The brain distribution was modestly enhanced in Mdr1a/b^-/-, Bcrp1^-/-, and Mdr1a/b^-/-Bcrp1^-/- knockout mice. The nonspecific binding of E6201 was higher in brain compared with plasma. However, free-drug concentrations in brain following 40 mg/kg intravenous dose reach levels that exceed reported in vitro half-maximal inhibitory concentration (IC₅₀) values, suggesting that E6201 may be efficacious in inhibiting MEK-driven brain tumors. The brain distribution characteristics of E6201 make it an attractive targeted agent for clinical testing in MBM, glioblastoma, and other CNS tumors that may be effectively targeted with inhibition of MEK signaling.

Tumor Resection Recruits Effector T Cells and Boosts Therapeutic Efficacy of Encapsulated Stem Cells Expressing IFNβ in Glioblastomas

Purpose: Despite tumor resection being the first-line clinical care for glioblastoma (GBM) patients, nearly all preclinical immune therapy models intend to treat established GBM. Characterizing cytoreductive surgery-induced immune response combined with the administration of immune cytokines has the potential of offering a new treatment paradigm of immune therapy for GBMs.Experimental Design: We developed syngeneic orthotopic mouse GBM models of tumor resection and characterized the immune response of intact and resected tumors. We also created a highly secretable variant of immune cytokine IFNβ to enhance its release from engineered mouse mesenchymal stem cells (MSC-IFNβ) and assessed whether surgical resection of intracranial GBM tumor significantly enhanced the antitumor efficacy of targeted on-site delivery of encapsulated MSC-IFNβ.Results: We show that tumor debulking results in substantial reduction of myeloid-derived suppressor cells (MDSC) and simultaneous recruitment of CD4/CD8 T cells. This immune response significantly enhanced the antitumor efficacy of locally delivered encapsulated MSC-IFNβ via enhanced selective postsurgical infiltration of CD8 T cells and directly induced cell-cycle arrest in tumor cells, resulting in increased survival of mice. Utilizing encapsulated human MSC-IFNβ in resected orthotopic tumor xenografts of patient-derived GBM, we further show that IFNβ induces cell-cycle arrest followed by apoptosis, resulting in increased survival in immunocompromised mice despite their absence of an intact immune system.Conclusions: This study demonstrates the importance of syngeneic tumor resection models in developing cancer immunotherapies and emphasizes the translational potential of local delivery of immunotherapeutic agents in treating cancer. Clin Cancer Res; 23(22); 7047-58. ©2017 AACR.

Future Advances in Spine Surgery: The AOSpine North America Perspective

This focus issue highlights state-of-the-art techniques, equipment, and practices in the modern era of spine surgery while providing a glimpse into the next generation of patient care. A broad range of topics are presented to cover the full spectrum of the field. Degenerative diseases are discussed in a series of 3 articles on (1) pathophysiology, management, and surgical approaches to degenerative cervical myelopathy; (2) novel approaches to degenerative thoracolumbar disease (eg, interspinous process spacers, minimally invasive/endoscopic approaches); and (3) animal models and emerging therapeutics in degenerative disk disease. Also included is a unique study aiming to establish the critically important cost-benefit relationship for spine procedures with perspectives on how value is defined and how to address variability.Primary and metastatic spine oncology are reviewed with a focus on upcoming targeted biologics, subspecialized radiotherapy (eg, proton-beam, carbon-ion, stereotactic radiosurgery), genetic profiling to stratify risk, and morbidity-reducing surgical approaches (eg, minimally invasive/endoscopic resections, percutaneous instrumentation). Trauma is discussed in 2 high-quality papers on controversies in spinal trauma and neuroprotective/neuroregenerative interventions for traumatic spinal cord injury. A stimulating article on cervical, thoracolumbar, and pediatric deformity highlights the rapid evolution of deformity surgery with a look at innovative tools (eg, high-fidelity 3-dimensional reconstructions, magnetically controlled growing rods) and their impact on quality of life. Additionally, a must-read article on surgical site infections discusses key risk factors and evidence-based preventative techniques to remain aware of. Finally, cutting-edge technologies, including computer-assisted navigation, shared-control robotics, neuromodulation, novel osteobiologics, and biomaterials, are covered in detail in a series of 3 fascinating papers on the next generation of the field.Each section intends to highlight the salient literature and afford insights from multiple key thought leaders in an effort to minimize bias and provide varied perspectives. Overall, we hope this issue provides high-quality, evidence-based data relevant to trainees and practicing surgeons while also stimulating excitement about the future of spine surgery.

Identification of pyrrolopyrimidine derivative PP-13 as a novel microtubule-destabilizing agent with promising anticancer properties

Despite the emergence of targeted therapies and immunotherapy, chemotherapy remains the gold-standard for the treatment of most patients with solid malignancies. Spindle poisons that interfere with microtubule dynamics are commonly used in chemotherapy drug combinations. However, their troublesome side effects and the emergence of chemoresistance highlight the need for identifying alternative agents. We performed a high throughput cell-based screening and selected a pyrrolopyrimidine molecule (named PP-13). In the present study, we evaluated its anticancer properties in vitro and in vivo. We showed that PP-13 exerted cytotoxic effects on various cancer cells, including those resistant to current targeted therapies and chemotherapies. PP-13 induced a transient mitotic blockade by interfering with both mitotic spindle organization and microtubule dynamics and finally led to mitotic slippage, aneuploidy and direct apoptotic death. PP-13 was identified as a microtubule-targeting agent that binds directly to the colchicine site in β-tubulin. Interestingly, PP-13 overcame the multidrug-resistant cancer cell phenotype and significantly reduced tumour growth and metastatic invasiveness without any noticeable toxicity for the chicken embryo in vivo. Overall, PP-13 appears to be a novel synthetic microtubule inhibitor with interesting anticancer properties and could be further investigated as a potent alternative for the management of malignancies including chemoresistant ones.

BRAF Inhibitors Amplify the Proapoptotic Activity of MEK Inhibitors by Inducing ER Stress in NRAS-Mutant Melanoma

Purpose: NRAS mutations in malignant melanoma are associated with aggressive disease requiring rapid antitumor intervention, but there is no approved targeted therapy for this subset of patients. In clinical trials, the MEK inhibitor (MEKi) binimetinib displayed modest antitumor activity, making combinations a requisite. In a previous study, the BRAF inhibitor (BRAFi) vemurafenib was shown to induce endoplasmic reticulum (ER) stress that together with inhibition of the RAF-MEK-ERK (MAPK) pathway amplified its proapoptotic activity in BRAF-mutant melanoma. The present study investigated whether this effect might extent to NRAS-mutant melanoma, in which MAPK activation would be expected.Experimental Design and Results: BRAFi increased pERK, but also significantly increased growth inhibition and apoptosis induced by the MEKi in monolayer, spheroids, organotypic, and patient-derived tissue slice cultures of NRAS-mutant melanoma. BRAFi such as encorafenib induced an ER stress response via the PERK pathway, as detected by phosphorylation of eIF2α and upregulation of the ER stress-related factors ATF4, CHOP, and NUPR1 and the proapoptotic protein PUMA. MEKi such as binimetinib induced the expression of the proapoptotic protein BIM and activation of the mitochondrial pathway of apoptosis, the latter of which was enhanced by combination with encorafenib. The increased apoptotic rates caused by the combination treatment were significantly reduced through siRNA knockdown of ATF4 and BIM, confirming its critical roles in this process.Conclusions: The data presented herein encourage further advanced in vivo and clinical studies to evaluate MEKi in combination with ER stress inducing BRAFi as a strategy to treat rapidly progressing NRAS-mutant melanoma. Clin Cancer Res; 23(20); 6203-14. ©2017 AACR.

Drug delivery to melanoma brain metastases: Can current challenges lead to new opportunities?

Melanoma has a high propensity to metastasize to the brain, and patients with melanoma brain metastases (MBM) have an extremely poor prognosis. The recent approval of several molecularly-targeted agents (e.g., BRAF, MEK inhibitors) and biologics (anti-CTLA-4, anti-PD-1 and anti-PD-L1 antibodies) has brought new hope to patients suffering from this formerly untreatable and lethal disease. Importantly, there have been recent reports of success in some clinical studies examining the efficacy of both targeted agents and immunotherapies that show similar response rates in both brain metastases and extracranial disease. While these studies are encouraging, there remains significant room for improvement in the treatment of MBM, given the lack of durable response and the development of resistance to current therapies. Critical questions remain regarding mechanisms that lead to this lack of durable response and development of resistance, and how those mechanisms may differ in systemic sites versus brain metastases. One issue that may not be fully appreciated is that the delivery of several small molecule molecularly-targeted therapies to the brain is often restricted due to active efflux at the blood-brain barrier (BBB) interface. Inadequate local drug concentrations may be partially responsible for the development of unique patterns of resistance at metastatic sites in the brain. It is clear that there can be local, heterogeneous BBB breakdown in MBM, as exemplified by contrast-enhancement on T1-weighted MR imaging. However, it is possible that the successful treatment of MBM with small molecule targeted therapies will depend, in part, on the ability of these therapies to penetrate an intact BBB and reach the protected micro-metastases (so called "sub-clinical" disease) that escape early detection by contrast-enhanced MRI, as well as regions of tumor within MRI-detectable metastases that may have a less compromised BBB. The emergence of resistance in MBM may be related to several diverse, yet interrelated, factors including the distinct microenvironment of the brain and inadequate brain penetration of targeted therapies to specific regions of tumor. The tumor microenvironment has been ascribed to play a key role in steering the course of disease progression, by dictating changes in expression of tumor drivers and resistance-related signaling mechanisms. Therefore, a key issue to consider is how changes in drug delivery, and hence local drug concentrations within a metastatic microenvironment, will influence the development of resistance. Herein we discuss our perspective on several critical questions that focus on many aspects relevant to the treatment of melanoma brain metastases; the answers to which may lead to important advances in the treatment of this devastating disease.

Targeted Therapies for Melanoma Brain Metastases

Brain metastases are a major clinical challenge occurring in up to 60% of patients suffering from metastatic melanoma. They cause significant clinical symptoms and impair the overall survival prognosis. The introduction of targeted therapies including BRAF and MEK inhibitors as well as CTLA-4 and PD-1 axis targeting immune checkpoint inhibitors have dramatically improved the treatment and prognosis of patients with extracranial metastatic melanoma. Although, similar response rates for extra- and intracranial metastases have been reported, only few data from brain metastasis specific trails are available so far. The following review will provide an overview on the currently available data on targeted therapies, remaining questions and the most important side effects in the special clinical situation of melanoma brain metastases.

BRAF Signaling Pathway Inhibition, Podocyte Injury, and Nephrotic Syndrome

Dabrafenib and trametinib, BRAF and MEK inhibitors, respectively, are effective targeted metastatic melanoma therapies, but little is known about their nephrotoxicity. Although tubulointerstitial injury has been the most widely reported renal side effect of targeted melanoma therapy, nephrotic syndrome has not been reported before. We report on a patient with metastatic melanoma who developed nephrotic syndrome during dabrafenib and trametinib treatment. Kidney biopsy showed diffuse loss of podocyte cytoarchitecture, extensive foot-process effacement, and glomerular endothelial injury. Kidney function and glomerular ultrastructural changes recovered fully after drug withdrawal. In vitro, BRAF inhibition decreased PLCε1 expression in podocytes, accompanied by a reduction in nephrin expression and an increase in permeability to albumin. Additionally, these drugs inhibited the podocyte-vascular endothelial growth factor (VEGF) system. In addition to implications for nephrotic syndrome pathophysiology, we suggest that patients given dabrafenib and trametinib be monitored closely for potential glomerular damage.

Phenotype-based variation as a biomarker of sensitivity to molecularly targeted therapy in melanoma

Transcriptomic phenotypes defined for melanoma have been reported to correlate with sensitivity to various drugs. In this study, we aimed to define a minimal signature that could be used to distinguish melanoma sub-types in vitro, and to determine suitable drugs by which these sub-types can be targeted. By using primary melanoma cell lines, as well as commercially available melanoma cell lines, we find that the evaluation of MLANA and INHBA expression is as capable as one based on a combined analysis performed with genes for stemness, EMT and invasion/proliferation, in identifying melanoma subtypes that differ in their sensitivity to molecularly targeted drugs. Using this approach, we find that 75% of melanoma cell lines can be treated with either the MEK inhibitor AZD6244 or the HSP90 inhibitor 17AAG.

Cutaneous adverse effects of the immune checkpoint inhibitors

The immune checkpoint targeted agents, anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and anti-programed cell death 1 (PD-1) or anti-programmed death ligand 1 (PD-L1) inhibitors are frequently associated with cutaneous side effects that are often dose limiting and can lead to discontinuation of therapy. Ipilimumab, a CTLA-4 inhibitor, is most commonly associated with a morbilliform eruption on the trunk and extremities and pruritus. More severe cutaneous toxicities reported include toxic epidermal necrolysis and severe drug rash with eosinophila and systemic symptoms. Recent case reports of Sweet syndrome and cutaneous sarcoidosis have also recently been described after treatment with ipilimumab. The cutaneous events usually occur early in the course of treatment and are dose dependent. PD-1 inhibitors, nivolumab and pembrolizumab, induce similar but less severe toxicities compared with the CTLA-4 inhibitors. The most common cutaneous adverse events include lichenoid reactions, eczema, vitiligo, and pruritus. Lichenoid oral mucosal lesions located on the tongue, buccal mucosa, lips, or gingivae or located on all of these have also recently been described. The time of onset of the cutaneous events with the PD-1 inhibitors occurs later than that seen with the CTLA-4 inhibitors. Anti-PD-L1 antibodies, such as atezolizumab, have a similar side effect profile compared with the PD-1 inhibitors. Combination of immune checkpoint inhibitors, ipilimumab and nivolumab, has recently been approved for the treatment of advanced melanoma. The combination therapy is associated with a more severe side effect profile compared with the agents used as monotherapy. We discuss the most frequently encountered cutaneous side effects of the immune checkpoint inhibitors and review the recommended management strategies.