B-rapidly Accelerated Fibrosarcoma Research Articles

Insights into the structure-activity relationship of pyrimidine-sulfonamide analogues for targeting BRAF V600E protein

B-rapidly accelerated fibrosarcoma (BRAF) V600E plays a crucial role in the progression of cutaneous melanoma. Core structures of BRAF V600E inhibitors are based on pyrimidine-sulfonamide scaffolds. Exploring the QSAR of these structures can improve our understanding of BRAF V600E inhibitor drug design. This study utilized machine learning-based QSAR to elucidate chemical substructures of pyrimidine-sulfonamide analogues that correlated to the BRAF V600E inhibitory activity. The findings indicate that the support vector regression (SVR) combined with 15 fingerprints achieved the highest statistical performances in terms of goodness-of-fit, robustness, and predictability. Nine key fingerprints from pyrimidine-sulfonamide analogues were identified to exert the BRAF V600E inhibitory activity. These key fingerprints were validated using network-based activity cliff landscape and molecular docking. Together, the developed algorithm can serve as a screening tool for designing BRAF V600E inhibitors. To further utilize this model, we deployed our developed algorithm at https://qsarlabs.com/#braf.

StackBRAF: A Large-Scale Stacking Ensemble Learning for BRAF Affinity Prediction.

The B-rapidly accelerated fibrosarcoma (BRAF) is a proto-oncogene that plays a vital role in cell signaling and growth regulation. Identifying a potent BRAF inhibitor can enhance therapeutic success in high-stage cancers, particularly metastatic melanoma. In this study, we proposed a stacking ensemble learning framework for the accurate prediction of BRAF inhibitors. We obtained 3857 curated molecules with BRAF inhibitory activity expressed as a predicted half-maximal inhibitory concentration value (pIC50) from the ChEMBL database. Twelve molecular fingerprints from PaDeL-Descriptor were calculated for model training. Three machine learning algorithms including extreme gradient boosting, support vector regression, and multilayer perceptron were utilized for constructing new predictive features (PFs). The meta-ensemble random forest regression, called StackBRAF, was created based on the 36 PFs. The StackBRAF model achieves lower mean absolute error (MAE) and higher coefficient of determination (R2 and Q2) than the individual baseline models. The stacking ensemble learning model provides good y-randomization results, indicating a strong correlation between molecular features and pIC50. An applicability domain of the model with an acceptable Tanimoto similarity score was also defined. Moreover, a large-scale high-throughput screening of 2123 FDA-approved drugs against the BRAF protein was successfully demonstrated using the StackBRAF algorithm. Thus, the StackBRAF model proved beneficial as a drug design algorithm for BRAF inhibitor drug discovery and drug development.

Dabrafenib-Panobinostat Salt: Improving the Dissolution Rate and Inhibition of BRAF Melanoma Cells.

Cocrystallization of the drug-drug salt-cocrystal of the histone deacetylase inhibitor (HDACi) panobinostat (PAN) and b-rapidly accelerated fibrosarcoma (BRAF) inhibitor dabrafenib (DBF) afforded single crystals of a two-drug salt stabilized by N+-H···O and N+-H···N- hydrogen bonds between the ionized panobinostat ammonium donor and dabrafenib sulfonamide anion acceptor in a 12-member ring motif. A faster dissolution rate for both drugs was achieved through the salt combination compared to the individual drugs in an aqueous acidic medium. The dissolution rate exhibited a peak concentration (Cmax) of approximately 310 mg cm-2 min-1 for PAN and 240 mg cm-2 min-1 for DBF at a Tmax of less than 20 min under gastric pH 1.2 (0.1 N HCl) compared to the pure drug dissolution values of 10 and 80 mg cm-2 min-1, respectively. The novel and fast-dissolving salt DBF-·PAN+ was analyzed in BRAFV600E melanoma cells Sk-Mel28. DBF-·PAN+ reduced the dose-response from micromolar to nanomolar concentrations and lowered IC50 (21.9 ± 7.2 nM) by half compared to PAN alone (45.3 ± 12.0 nM). The enhanced dissolution and lower survival rate of melanoma cells show the potential of novel DBF-·PAN+ salt in clinical evaluation.

An Update on the Role of Anti-EGFR in the Treatment of Older Patients with Metastatic Colorectal Cancer

Although colorectal cancer is increasingly being diagnosed in older patients, their number is largely underrepresented in phase II or III clinical trials. Consequently, guidelines and the SIOG recommendations are not sufficiently clear regarding the treatment of these patients, particularly when chemotherapy is combined with monoclonal antibodies (bevacizumab, cetuximab, and panitumumab). Targeted therapy based on the use of anti-epidermal growth factor receptors (EGFRs) is conditioned by the potential for increased toxicity, making it more difficult to treat an older, rat sarcoma virus (RAS) and B rapidly accelerated fibrosarcoma (BRAF) wild-type patient. In light of a more detailed characterization of the older population, modernly differentiable between fit, vulnerable, or frail patients on the basis of the comprehensive geriatric assessment, and of the analysis of more recent studies, this review fully collects data from the literature, differentiating the results on functional status patients.

Gene Mutations in the FGF-MAPK Signaling Pathway and Targeted Therapy in Ameloblastoma

Abstract Ameloblastoma is one of the most common odontogenic tumors in Asia. In the past decade, many studies have shown gene mutations in the mitogen-activated protein kinase (MAPK) signaling pathway, especially on an extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. Mutations of fibroblast growth factor receptor 2 (FGFR2), rat sarcoma virus (RAS), and B-rapidly accelerated fibrosarcoma (BRAF) are able to cause a continuous activation of the ERK1/2 signaling pathway, hence uncontrolled tumor cell proliferation. Due to the ERK1/2 signaling pathway role in cell growth and cell survival, upregulation of this pathway can cause approximately one-third of human tumors including ameloblastoma. After the discovery of gene mutations in several cancers, many inhibitors have been designed to target these mutations. We, here, reviewed the alteration of the FGF-MAPK signaling pathway in ameloblastoma and targeted treatment used as an adjuvant or neoadjuvant therapy for ameloblastoma especially in cases where wide surgical resection is needed. Keywords: Genetic, Growth factor, Mutation, Targeted therapy

Recognition of BRAF by CDC37 and Re-Evaluation of the Activation Mechanism for the Class 2 BRAF-L597R Mutant.

The kinome specific co-chaperone, CDC37 (cell division cycle 37), is responsible for delivering BRAF (B-Rapidly Accelerated Fibrosarcoma) to the Hsp90 (heat shock protein 90) complex, where it is then translocated to the RAS (protooncogene product p21) complex at the plasma membrane for RAS mediated dimerization and subsequent activation. We identify a bipartite interaction between CDC37 and BRAF and delimitate the essential structural elements of CDC37 involved in BRAF recognition. We find an extended and conserved CDC37 motif, 20HPNID---SL--W31, responsible for recognizing the C-lobe of BRAF kinase domain, while the c-terminal domain of CDC37 is responsible for the second of the bipartite interaction with BRAF. We show that dimerization of BRAF, independent of nucleotide binding, can act as a potent signal that prevents CDC37 recognition and discuss the implications of mutations in BRAF and the consequences on signaling in a clinical setting, particularly for class 2 BRAF mutations.

Low Vitamin D Status Predicts Poor Clinical Outcome in Advanced Melanoma Treated With Immune Checkpoint or BRAF/MEK Inhibitors: A Prospective Non-Interventional Side-by-Side Analysis.

In melanoma and other malignancies, low vitamin D status is associated with increased risk and poor prognosis. However, there are limited data of the impact of 25(OH)D serum concentration (s.c.) on clinical outcome in advanced melanoma. We tested the hypothesis that vitamin D status is predictive of efficacy and safety in patients treated for metastasized melanoma with B-rapidly accelerated fibrosarcoma (BRAF), mitogen-activated protein kinase kinase (MEK), cytotoxic T lymphocyte-associated protein-4 (CTLA-4), and/or programmed cell death protein-1 (PD-1) inhibitors. Severe vitamin D deficiency [defined as 25(OH)D s.c. <10 ng/ml] was associated with markedly reduced overall (OS) and progress-free (PFS) survival, with increased tumor load [TL; measured as s.c. of S100 protein or lactate dehydrogenase (LDH)], and with a trend for higher frequency of adverse events (AEs). An increase in average 25(OH)D s.c. of 1 ng/ml was associated with a 3.9% reduced risk for progressive disease [hazard ratio (HR) = 0.961, p = 0.044], with a reduction of LDH s.c. of 3.86 U/l (p = 0.034, indicating a reduction of TL), and with a trend for reduced frequency of AEs (AE ratio -0.005; p = 0.295). Patients with average 25(OH)D s.c. ≥10 ng/ml and BRAF-mutant melanoma showed a trend for a higher frequency of AEs as compared to individuals with BRAF wild-type melanomas. Our data indicate that vitamin D deficiency is associated with poor clinical outcome in patients treated for metastasized melanoma with BRAF/MEK inhibitors or immunotherapy. Although it needs to be proven in future interventional trials whether optimizing serum 25(OH)D improves clinical outcome in these patients, we recommend that 25(OH)D s.c. should be analyzed and vitamin D deficiency treated in all patients with advanced melanoma.

Sorafenib inhibits tumor cell growth and angiogenesis in canine transitional cell carcinoma.

Canine transitional cell carcinoma (cTCC) is the most common naturally occurring bladder cancer and accounts for 1–2% of canine tumors. The prognosis is poor due to the high rate of invasiveness and metastasis at diagnosis. Sorafenib is a multi-kinase inhibitor that targets rapidly accelerated fibrosarcoma (RAF), vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, VEGFR-3, platelet-derived growth factor receptor-β (PDGFR-β), and KIT. In previous studies, a somatic mutation of B-rapidly accelerated fibrosarcoma (BRAF) and expressions of VEGFR-2 and PDGFR-β were observed in over 80% of patients with cTCC. Therefore, in this study, we investigated the anti-tumor effects of sorafenib on cTCC. Five cTCC cell lines were used in the in vitro experiments. All five cTCC cell lines expressed VEGFR-2 and PDGFR-β and sorafenib showed growth inhibitory effect on cTCC cell lines. Cell cycle arrest at the G0/G1 phase and subsequent apoptosis were observed following sorafenib treatment. In the in vivo experiments, cTCC (Sora) cells were subcutaneously injected into nude mice. Mice were orally administered with sorafenib (30 mg/kg daily) for 14 days. Sorafenib inhibited tumor growth compared to vehicle control. The necrotic area in the tumor tissues was increased in the sorafenib-treated group. Sorafenib also inhibited angiogenesis in the tumor microenvironment. Thus, sorafenib may be potential therapeutic agent for cTCC via its direct anti-tumor effect and inhibition of angiogenesis.

&lt;i&gt;In Silico&lt;/i&gt;, Design, and Development: Molecular Modeling towards B-RAF and VEGFR-2 of Novel Sorafenib Derivatives for Targeted Hepatocellular Carcinoma Cancer Inhibitors

Hepatocellular carcinoma (HCC) is a major public health problem and the leading cause of death of people around the world with a tendency to increase every year, leading to a large investigation on the development of HCC drugs. In this work, novel sorafenib derivatives containing 1,2,3-triazole moiety, M1-M5 were designed as potential HCC cancer inhibitors by targeting B-rapidly accelerated fibrosarcoma (B-RAF) and vascular endothelial growth factor receptor 2 (VEGFR-2). The bindings of M1-M5 in the cavity of B-RAF and VEGFR-2, which are kinases related to HCC cell growth, were investigated by molecular docking using iGEMDOCK v2.1 software. The results illustrated that M1-M5 bound in the binding site of B-RAF and VEGFR-2 in a similar manner to sorafenib. It was also found that the 1,2,3-triazole moiety of M1-M5 interacted well by hydrogen bonding with key amino acids in the binding site of B-RAF and VEGFR-2 which could inhibit the cancer cell growth. Although the binding energies of M1-M5 in B-RAF (-148.51 to -126.19 kcal/mol) were rather higher to that of sorafenib (-176.75 kcal/mol), the binding energies of M1-M5 in VEGFR-2 (-127.00 to -116.48 kcal/mol) were comparable to that of sorafenib (-127.03 kcal/mol). As a result, M1-M5 containing 1,2,3-triazole moiety were promising molecules to study in vitro on VEGFR-2 inhibitory assay and be leading compounds for the development as the anticancer drugs against HCC in the future.

DRP1 Promotes BRAFV600E-Driven Tumor Progression and Metabolic Reprogramming in Colorectal Cancer.

BackgroundMitochondria are highly dynamic organelles which remain in a continuous state of fission/ fusion dynamics to meet the metabolic needs of a cell. However, this fission/fusion dynamism has been reported to be dysregulated in most cancers. Such enhanced mitochondrial fission is demonstrated to be positively regulated by some activating oncogenic mutations; such as those of KRAS (Kristen rat sarcoma viral oncogene homologue) or BRAF (B- rapidly accelerated fibrosarcoma), thereby increasing tumor progression/ chemotherapeutic resistance and metabolic deregulation. However, the underlying mechanism(s) are still not clear, thus highlighting the need to further explore possible mechanism(s) of intervention. We sought to investigate how BRAFV600E driven CRC (colorectal cancer) progression is linked to mitochondrial fission/fusion dynamics and whether this window could be exploited to target CRC progression.MethodsWestern blotting was employed to study the differences in expression levels of key proteins regulating mitochondrial dynamics, which was further confirmed by confocal microscopy imaging of mitochondria in endogenously expressing BRAFWT and BRAFV600E CRC cells. Proliferation assays, soft agar clonogenic assays, glucose uptake/lactate production, ATP/ NADPH measurement assays were employed to study the extent of carcinogenesis and metabolic reprograming in BRAFV600E CRC cells. Genetic knockdown (shRNA/ siRNA) and/or pharmacologic inhibition of Dynamin related protein1/Pyruvate dehydrogenase kinase1 (DRP1/PDK1) and/or BRAFV600E were employed to study the involvement and possible mechanism of these proteins in BRAFV600E driven CRC. Statistical analyses were carried out using Graph Pad Prism v 5.0, data was analyzed by unpaired t-test and two-way ANOVA with appropriate post hoc tests.ResultsOur results demonstrate that BRAFV600E CRC cells have higher protein levels of mitochondrial fission factor- DRP1/pDRP1S616 leading to a more fragmented mitochondrial state compared to those harboring BRAFWT. This fragmented mitochondrial state was found to confer glycolytic phenotype, clonogenic potential and metastatic advantage to cells harboring BRAFV600E. Interestingly, such fragmented mitochondrial state seemed positively regulated by mitochondrial PDK1 as observed through pharmacologic as well as genetic inhibition of PDK1.ConclusionIn conclusion, our data suggest that BRAFV600E driven colorectal cancers have fragmented mitochondria which confers glycolytic phenotype and growth advantage to these tumors, and such phenotype is dependent at least in part on PDK1- thus highlighting a potential therapeutic target.

BRAF Mutant Melanoma Adjusts to BRAF/MEK Inhibitors via Dependence on Increased Antioxidant SOD2 and Increased Reactive Oxygen Species Levels.

B-Rapidly Accelerated Fibrosarcoma (BRAF) mutations are found in about 50% of melanoma patients. Treatment with Food and Drug Administration (FDA)-approved BRAF and MAP/ERK kinase (MEK) inhibitors has improved progression free and overall survival of patients with BRAF mutant melanoma. However, all responders develop resistance typically within 1 year of treatment with these inhibitors. Evidence indicates that reactive oxygen species (ROS) levels are elevated after BRAF pathway inhibition treatment. We aim to decipher the role of mitochondrial antioxidant proteins relative to ROS levels and BRAF pathway inhibitor resistance. We observed BRAF mutant melanoma cells treated with the combination of a MEK inhibitor (trametinib) and a BRAF inhibitor (dabrafenib), exhibited elevated ROS levels, both in in vitro and in vivo melanoma models. We next generated trametinib- and dabrafenib-resistant (TDR) cells and found increased ROS levels after acquisition of resistance. An immunofluorescence experiment showed an increase of DNA damage in TDR cell lines. Furthermore, we observed that TDR cells increased superoxide dismutase 2 (SOD2), an antioxidant, at both mRNA and protein levels, with the upregulation of the transcription factor Nuclear Factor (NF)-κB. Knockdown of SOD2 significantly reduced the growth of BRAF pathway inhibitor-resistant cells. In addition, the results indicate that TDR cells can be re-sensitized to BRAF pathway inhibitors by the ROS scavenger, N-Acetyl Cysteine (NAC). Overall, these data indicate that BRAF pathway inhibitor-resistant cells can compensate for elevated ROS via increased expression of the antioxidant SOD2.

Detection of the BRAF V600E Mutation in Colorectal Cancer by NIR Spectroscopy in Conjunction with Counter Propagation Artificial Neural Network.

This paper proposes a sensitive, sample preparation-free, rapid, and low-cost method for the detection of the B-rapidly accelerated fibrosarcoma (BRAF) gene mutation involving a substitution of valine to glutamic acid at codon 600 (V600E) in colorectal cancer (CRC) by near-infrared (NIR) spectroscopy in conjunction with counter propagation artificial neural network (CP-ANN). The NIR spectral data from 104 paraffin-embedded CRC tissue samples consisting of an equal number of the BRAF V600E mutant and wild-type ones calibrated and validated the CP-ANN model. As a result, the CP-ANN model had the classification accuracy of calibration (CAC) 98.0%, cross-validation (CACV) 95.0% and validation (CAV) 94.4%. When used to detect the BRAF V600E mutation in CRC, the model showed a diagnostic sensitivity of 100.0%, a diagnostic specificity of 87.5%, and a diagnostic accuracy of 93.8%. Moreover, this method was proven to distinguish the BRAF V600E mutant from the wild type based on intrinsic differences by using a total of 312 CRC tissue samples paraffin-embedded, deparaffinized, and stained. The novel method can be used for the auxiliary diagnosis of the BRAF V600E mutation in CRC. This work can expand the application of NIR spectroscopy in the auxiliary diagnosis of gene mutation in human cancer.

The spectrum of cutaneous adverse events during encorafenib and binimetinib treatment in B-rapidly accelerated fibrosarcoma-mutated advanced melanoma.

B-rapidly accelerated fibrosarcoma (BRAF) inhibitor encorafenib alone and in combination with MEK inhibitor binimetinib improves survival in BRAF-mutated melanoma patients. So far, the range of cutaneous adverse events has been characterized only for established BRAF inhibitors (vemurafenib, dabrafenib) and MEK inhibitors (trametinib, cobimetinib). The aim of this study was to investigate cutaneous adverse events emerging in melanoma patients treated with encorafenib and binimetinib. Patients treated with BRAF and MEK inhibitors in clinical trials at the University Hospital of Zurich were identified. Frequency and features of cutaneous adverse events as well as their management were assessed based on the prospectively collected clinical and histopathological data. The events emerging during encorafenib and/or binimetinib therapy were compared to other BRAF and MEK inhibitors at the institution and in the literature. The most frequent cutaneous adverse events observed in patients treated with encorafenib alone (n=24) were palmoplantar hyperkeratosis (54%), palmoplantar erythrodysesthesia (58%) and alopecia (46%). Drug-induced papulopustular eruptions prevailed in patients with binimetinib monotherapy (n=25). The most frequent cutaneous adverse events in patients treated with encorafenib/binimetinib (n=49) were palmoplantar hyperkeratosis (10%). Compared to data published for established BRAFi, encorafenib monotherapy showed less hyperproliferative cutaneous adverse events. In contrast, palmoplantar hyperkeratosis and palmoplantar erythrodysesthesia seem to occur more often. The combination of encorafenib and binimetinib is well tolerated and induces few cutaneous adverse events.

Ampulla of Vater Carcinoma: Sequencing Analysis Identifies TP53 Status as a Novel Independent Prognostic Factor and Potentially Actionable ERBB, PI3K, and WNT Pathways Gene Mutations.

To identify molecular prognostic factors and potentially actionable mutations in ampulla of Vater cancer (AVC). The largely variable outcomes of AVCs make clinical decisions difficult regarding the need of postsurgical therapy, which is based on morphological and immunohistochemical classification that do not adequately consider the varying degrees of heterogeneity present in many AVCs. No approved targeted therapies for AVC exist, but some show promising results requiring better molecular characterization to identify potential responders. We assessed 80 AVCs for the prognostic value of mutations of kirsten rat sarcoma (KRAS), neuroblastoma RAS (NRAS), B rapidly accelerated fibrosarcoma (BRAF), TP53, and 4 membrane erythroblastosis oncogene B (ERBB) receptor tyrosine kinases (EGFR-ERBB1, HER2-ERBB2, HER3-ERBB3, HER4-ERBB4) amenable to pharmacological inhibition. Moreover, we evaluated mutations in 16 key components of rat sarcoma (RAS), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), protein 53 (P53), transforming growth factor beta (TGF-β), and wingless/integrated (WNT) pathways, recently associated to AVC by whole-exome sequencing. TP53 and KRAS were mutated in 41% and 35% of cases, respectively, and emerged as independent prognostic factors together with tumor stage and regardless of the histotype (TP53: P = 0.0006; KRAS: P = 0.0018; stage IIB: P = 0.0117; stage III-IV: P = 0.0020). ERBB, WNT and PI3K pathway genes were mutated in 37.5% of cases. KRAS and TP53 mutations are negative predictors of survival in AVCs, regardless of histotype. Potentially actionable mutations in ERBB, WNT, and PI3K signaling pathway genes are present in 37.5% of all cases. These might be amenable to target therapy using available drugs like Everolimus in PI3K-mutated cases or compounds under active screening against ERBB and WNT signaling.

Impact of phosphoinositide-3-kinase and vitamin D3 nuclear receptor single-nucleotide polymorphisms on the outcome of malignant melanoma patients.

BackgroundSeveral studies associating single nucleotide polymorphisms (SNPs) frequencies with tumors outcome have been conducted, nevertheless malignant melanoma literature data are inconclusive.Therefore we evaluate the impact of different genotypes for phosphoinositide-3-kinase (PI3K) and vitamin D3 nuclear receptor (VDR) SNPs on melanoma patients’ outcome.Materials and methodsGenomic DNA of 88 patients was extracted from blood and tumor samples. SNPs were determined by PCR using TaqMan assays. We selected polymorphisms of the regulatory and catalytic subunit of PI3K (PIK3R1 and PIK3CA genes, respectively), analyzing rs2699887C>T of PIK3CA and rs3730089G>A of PIK3R1 SNPs. Furthermore we considered the following VDR SNPs: rs2228570A>G (Fok1), rs731236A>G (Taq1) and rs1544410C>T (Bsm1).Progression free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method and with Mantel-Haenszel log-rank test.ResultsThe statistical analysis for Fok1 of VDR showed a significant difference in PFS after the first line therapy (median PFS= 21.2 months in the homozygous recessive genotype group vs. 3.3 months of homozygous dominant and heterozygous ones, p= 0.03). In particular, in homozygous recessive patients for Fok1 SNPs of VDR a high rate of histological regression and BRAF (B- Rapidly Accelerated Fibrosarcoma gene) mutation were observed. Furthermore, more efficacy of BRAF +/- MEK (MAPK-ERK-Kinase) inhibitors therapies in homozygous recessive patients vs. homozygous dominant and heterozygous ones was shown.ConclusionsOur study showed a significant correlation between homozygous recessive genotype of Fok1 SNPs of VDR gene and an increased PFS in patients who underwent a first line therapy with BRAF inhibitors.

MEK162 Enhances Antitumor Activity of 5-Fluorouracil and Trifluridine in KRAS-mutated Human Colorectal Cancer Cell Lines.

Preclinical evidence demonstrates that mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway inhibition increases sensitivity to 5-fluorouracil (5-FU) in colorectal cancer (CRC) cell lines and xenografts. Here, we aimed to investigate how CRC cell sensitivity to this combination is correlated to Kirsten rat sarcoma (KRAS) and proto-oncogene B-rapidly accelerated fibrosarcoma (BRAF) mutation, that are common in CRC and often lead to resistance to chemotherapy. Wild-type and mutant KRAS/BRAF human CRC cell lines were treated with escalating doses of 5-FU or trifluridine with MEK162 (MEK1/2 inhibitor) for 72 h. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and synergism expressed by the combination index was calculated using CalcuSyn. Evidence of synergistic antitumor activity was observed for the majority of human CRC cell lines treated with MEK162 plus 5-FU (4/6) or trifluridine (7/9). Synergism was greater in KRAS- or BRAF-mutant cell lines compared to wild-type KRAS/BRAF CRC cell lines. The combination of MEK inhibition and trifluridine is worthwhile advancing in clinical development, particularly for treatment-refractory KRAS- or BRAF-mutated metastatic CRC.

BRAF gene alterations and enhanced mammalian target of rapamycin signaling in gangliogliomas.

Gangliogliomas (GGs) are slow-growing glioneuronal tumors seen in children and young adults. They are associated with intractable epilepsy, and have recently been found to harbor BRAF (B- rapidly accelerated fibrosarcoma) gene mutations. However, the mammalian target of rapamycin (mTOR) signaling pathway, downstream of BRAF, has not been evaluated extensively in GGs. GG cases were retrieved, clinical data obtained, and histopathological features reviewed. Sequencing for BRAF V600E mutation, analysis of BRAF copy number by quantitative real-time polymerase chain reaction, and immunohistochemistry for mTOR pathway markers p-S6 and p-4EBP1 were performed. Sixty-four cases of GG were identified (0.9% of central nervous system tumors). Of these, 28 had sufficient tumor tissue for further evaluation. Mixed glial and neuronal morphology was the commonest (64%) type. Focal cortical dysplasia was identified in the adjacent cortex (6 cases). BRAF V600E mutation was identified in 30% of GGs; BRAF copy number gain was observed in 50% of them. p-S6 and p-4EBP1 immunopositivity was seen in 57% cases each. Thus, mTOR pathway activation was seen in 81% cases, and was independent of BRAF alterations. 87% patients had Engel grade I outcome, while 13% had Engel grade II outcome. Both the Engel grade II cases analyzed showed BRAF V600E mutation. BRAF V600E mutation is frequent in GGs, as is BRAF gain; the former may serve as a target for personalized therapy in patients with residual tumors, necessitating its assessment in routine pathology reporting of these tumors. Evidence of mTOR pathway activation highlights similarities in the pathogenetic mechanisms underlying GG and focal cortical dysplasia, and suggests that mTOR inhibitors may be of utility in GG patients with persistent seizures after surgery.

Targeting the RAS pathway by mitogen-activated protein kinase inhibitors.

Targeting of oncogenic driver mutations with small-molecule inhibitors resulted in powerful treatment options for cancer patients in recent years. The RAS (rat sarcoma) pathway is among the most frequently mutated pathways in human cancer. Whereas targeting mutant Kirsten RAS (KRAS) remains difficult, mutant B rapidly accelerated fibrosarcoma (BRAF) kinase is an established drug target in cancer. Now data show that neuroblastoma RAS (NRAS) and even Harvey RAS (HRAS) mutations could be predictive markers for treatment with mitogen-activated protein kinase (MEK) inhibitors. This review discusses recent preclinical and clinical studies of MEK inhibitors in BRAF and RAS mutant cancer.

Optic nerve glioma: case series with review of clinical, radiologic, molecular, and histopathologic characteristics.

This study was designed to better understand the biologic nature of optic nerve gliomas (ONGs) and to investigate staining techniques that might improve the pathologic interpretation of surgical margins. In this retrospective case series, clinical data on patient presentation, MRI, surgical visualization, and initial pathologic interpretation were gathered. Specimens were then reexamined using analysis of p53, isocitrate dehydrogenase 1 (IDH1), MIB-1, and B-rapidly accelerated fibrosarcoma (BRAF) duplication. Six patients were studied. All were diagnosed with World Health Organization grade 1 ONGs on original pathology. On reexamination, BRAF tandem duplication was found in 2 patients with neurofibromatosis Type 1 association. P53 immunoreactivity was noted in a third case. No cases had IDH1 immunoreactivity. Focal elevations of MIB-1 up to 7.5% were noted in 2 cases. ONGs are neoplasms with variable degrees of aggressiveness. As more is understood regarding their varied genetic underpinnings, improved pathologic classification and individualized treatment regimens may be achieved. The authors hope that this study helps guide the oculoplastic community toward a multi-institutional, prospective study of ONG genomic sequencing.