Resistance to BRAF inhibition in melanoma: An epigenetic approach.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e19040-e19040 ◽  
Author(s):  
Steve Walston ◽  
Nicolaus Gordon ◽  
Arnab Chakravarti ◽  
Kamalakannan Palanichamy
Keyword(s):  
Targeted Therapy ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Treatment Options ◽  
Single Agent ◽  
Annexin V ◽  
Invasive Disease ◽  
Braf V600e ◽  
Cancer Genes ◽  
Braf Inhibition

e19040 Background: Melanoma only accounts for 4% of skin cancer while causing 75% of cancer related deaths. Worldwide incidence is increasing faster than any other cancer, and there are few effective treatment options for invasive disease translating to poor survival. The burgeoning understanding of molecular mechanisms driving carcinogenesis creates unique opportunities to develop targeted therapy. This is especially apparent in the case of BRAF in melanoma. BRAF V600E mutations occur in up to 50% of melanomas endowing these tumors with a constitutively activated MAPK pathway. Blockade of BRAF mutated tumors shows impressive initial responses above 80%. However, single-agent targeted therapy is often plagued with an emergence of resistant clones, and these impressive responses were transient. Diverse resistance mechanisms have been reported at the transcriptome level in patients treated with BRAF inhibitors. However, reports elucidating the prominent epigenetic regulators of resistance to BRAF inhibition are lacking. Methods: We sequenced the DNA of 14 melanoma cell lines and determined 9 had BRAF V600E mutation and 5 were wild type. We also sequenced cancer genes such as p53, PTEN, cKit, NRAS, etc. The BRAF mutant cells were exposed to PLX4032 (BRAF V600E inhibitor) and the concentrations were incrementally increased to develop resistant clones. This resistance was corroborated using annexin V / PI assay to display approximately a 50% decrease in apoptosis in drug resistant cells compared with control cells after 5 days of 5 µM PLX4032 exposure. The epigenome was profiled in control and resistance clones. Results: The statistically significant clusters were identified and currently we are validating their relevance using functional models. We are also profiling the epigene expression levels in melanoma patient biopsies to determine their predictive and prognostic value. Conclusions: It is likely the epigenome plays an integral role in the previously demonstrated mechanisms of BRAF resistance. Our study should illuminate connections with pathways conveying drug resistance to increase understanding of these mechanisms. Consequently, it may be possible to develop improved treatments and prognostic biomarkers.

scholarly journals Vulpinic Acid as a Natural Compound Inhibits the Proliferation of Metastatic Prostate Cancer Cell by Inducing Apoptosis

2021 ◽  
Author(s):  
Demet Cansaran Duman ◽  
Gamze Guney Eskiler ◽  
Betül Çolak ◽  
Elif Sozen Kucukkara
Keyword(s):  
Prostate Cancer ◽  
Metastatic Prostate Cancer ◽  
Molecular Mechanisms ◽  
Treatment Options ◽  
Annexin V ◽  
Current Treatment ◽  
Pcr Analysis ◽  
G1 Arrest ◽  
Advanced Analysis ◽  
Induced Apoptosis

Abstract Lichen secondary metabolites have drawn considerable attention in recent years due to limitations of current treatment options. Vulpinic acid (VA) obtained from Letharia vulpina lichen species exerts a remarkable cytotoxic effect on different cancer types. However, the therapeutic efficacy of VA in metastatic prostate cancer (mPC) cells has not been investigated. In the present study, we aimed to identify VA-mediated cytotoxicity in PC-3 mPC cells compared with control cells. After identification of the cytotoxic concentrations of VA, VA induced apoptosis was analyzed by Annexin V, cell cycle, acridine orange and propidium iodide staining and RT-PCR analysis. Our findings showed that VA significantly decreased the viability of PC-3 cells (p < 0.01) and caused a considerable early apoptotic effect through G0/G1 arrest, nuclear bleebing and the activation of particularly initiator caspases. Therefore, VA may be a potential treatment option for mPC patients. However, the underlying molecular mechanisms of VA-induced apoptosis with advanced analysis should be further performed.

scholarly journals Systemic treatment options for advanced biliary tract carcinoma

2020 ◽  
Vol 55 (10) ◽  
pp. 944-957
Author(s):  
Changqing Xie ◽  
Nicole A. McGrath ◽  
Cecilia Monge Bonilla ◽  
Jianyang Fu
Keyword(s):  
Clinical Trials ◽  
Targeted Therapy ◽  
Biliary Tract ◽  
Treatment Options ◽  
Single Agent ◽  
Current Status ◽  
Dna Mismatch ◽  
First Line Therapy ◽  
Molecular Landscape ◽  
Line Setting

Abstract Advanced biliary tract cancers (BTC) include a diverse collection of rare and heterogenous tumors with poor prognosis. The combination of gemcitabine and cisplatin is the established first-line therapy for advanced BTC. There are no accepted standard treatments in the second line setting, though there are several ongoing clinical trials that implement chemotherapy as a therapeutic strategy. The understanding of the molecular landscape of BTC has offered hope of targeted therapies to the identified actionable genomic aberrations, such as FGFR2 gene fusions, mutations of IDH1/2, HER2, BRAC1/2 and BRAF. Pembigatinib has become the first approved targeted therapy for BTC with FGFR2 fusion or other rearrangements. Recent immunotherapy has opened new therapy avenues in BTC with pembrolizumab approved for either microsatellite instability high (MSI-H) or DNA mismatch repair deficient (dMMR) advanced solid tumors, including BTC. The combination of immunotherapy with other modalities is currently being evaluated in different clinical trials, since single agent immunotherapy appears to provide modest benefits in advanced BTC. In this review, we summarize the current status of treatment options, including systemic chemotherapy, targeted therapy, immunotherapy, and various combinations in advanced BTC.

scholarly journals Targeted inhibition of the MAPK pathway: emerging salvage option for progressive life-threatening multisystem LCH

2017 ◽  
Vol 1 (6) ◽  
pp. 352-356 ◽  
Author(s):  
Alexandra Kolenová ◽  
Raphaela Schwentner ◽  
Gunhild Jug ◽  
Ingrid Simonitsch-Klupp ◽  
Christoph Kornauth ◽  
...  
Keyword(s):  
Clinical Response ◽  
Clinical Remission ◽  
Mapk Pathway ◽  
Single Agent ◽  
Braf V600e ◽  
Longitudinal Assessment ◽  
Key Points ◽  
Life Threatening ◽  
Targeted Inhibition

Key Points Single-agent vemurafenib leads to a rapid and sustained clinical response in severe multisystem LCH but does not eradicate the disease. Longitudinal assessment of BRAF V600E during treatment shows that clinical remission can occur despite significant amounts of mutated BRAF.

Diverse and Targetable Kinase Alterations Drive Histiocytic Neoplasms

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 481-481
Author(s):  
Benjamin Heath Durham ◽  
Eli L. Diamond ◽  
Julien Haroche ◽  
Zhan Yao ◽  
Jing Ma ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Single Agent ◽  
Braf V600e ◽  
Rna Seq ◽  
Wild Type ◽  
Employment Equity ◽  
Mek Inhibitors ◽  
Whole Exome ◽  
Recurrent Mutations ◽  
Equity Ownership

Abstract Histiocytic neoplasms are clonal, hematopoietic disorders characterized by an accumulation of abnormal monocyte-derived dendritic cells or macrophages in Langerhans Cell (LCH) and non-Langerhans (non-LCH) histiocytoses, respectively. The discovery of the BRAF V600E mutation in ~50% of patients with LCH and the non-LCH Erdheim-Chester Disease (ECD) provided the first molecular target in these patients and novel insights into the pathogenesis of these disorders. However, recurrent mutations in the majority of the ~50% of BRAF V600E-wild type patients with non-LCH are unknown. Moreover, recurrent mutations outside of the MAP kinase pathway are undefined throughout histiocytic neoplasms. To address these issues, we performed whole exome sequencing (WES) of frozen biopsies from 24 patients with LCH (n=10) or ECD (n=14) paired with peripheral blood mononuclear cells. 13/24 patients also underwent RNA sequencing (RNA-seq). All mutations in activating kinases were validated by droplet-digital PCR, while targeted-capture next-generation sequencing validated all others. Both adult (n=18; n=2 with LCH) and pediatric cases (n=9; n=8 with LCH) were included. Using combined WES/RNA-seq, activating kinase alterations were identified in 100% of patients. In LCH, 60% and 40% had BRAF V600E and MAP2K1 mutations, respectively. In non-LCH 51%, 14%, 14%, and 7% were BRAFV600E, ARAF, MAP2K1, and NRAS mutant (Fig1A). Overall, a mean of 7 non-synonymous mutations per adult patient was identified (range 1-22) compared with 5 mutations per pediatric patient (range 4-9; p =ns). Mutations affecting diverse cellular processes were found to co-exist with kinase mutations including mutations in epigenetic modifiers and the p38/MAPK pathway. In addition to kinase point mutations, RNA-seq identified recurrent, in-frame kinase fusions-a first for these disorders. All identified fusions were validated using FISH and RT-PCR. This includes novel fusions in BRAF (RNF11-BRAF and CLIP2-BRAF), as well as therapeutically important fusions in ALK (2 separate KIF5B-ALK fusions) and NTRK1 (LMNA-NTRK1;Fig1B). Expression of each fusion in Ba/F3 cells conferred cytokine-independent growth. Importantly, the BRAF fusions were found to be sensitive to MEK inhibition but resistant to vemurafenib while the ALK fusions conferred sensitivity to the ALK inhibitors crizotinib or alectinib. We next interrogated a validation cohort of 37 BRAF V600E-wild type, non-LCH, formalin-fixed, paraffin-embedded tissue samples using targeted mutational profiling for MAP2K1, ARAF, NRAS, KRAS, and PIK3CA. This revealed activating mutations in MAP2K1 (32%; n=12), NRAS (16%; n=6), KRAS (11%; n=4), PIK3CA (8%; n=3), and ARAF (3%; n=1). Three of the investigated non-LCH patients with refractory disease and progressive organ dysfunction were treated with targeted therapies based on the discovery of novel kinase alterations described above. Treatment of 2 refractory MAP2K1- mutant, non-LCH patients with MEK inhibitors (trametinib or cobimetinib) resulted in dramatic clinical improvement (Fig1C). Both patients have been maintained on MEK inhibitor single-agent therapy with a sustained clinical response for >100 days. Further evidence of effective targeted inhibition was found in a refractory ECD patient carrying an ARAF S214A mutation. This patient failed to respond to 3 lines of prior therapies and suffered near blindness due to disease infiltration in the retina and optic nerves. Given a recent report of complete response to sorafenib in a lung cancer patient with an ARAF S214C mutation, we initiated sorafenib. Within 12 weeks, there was improvement in the patientÕs eyesight and decreased infiltrative disease, coinciding with >50% decrease in mutant ARAF DNA in plasma cell-free DNA. Whole exome and transcriptome sequencing identified activating kinase mutations or translocations in all patients with the common downstream effect of activating the MAPK pathway. The preliminary, dramatic, clinical efficacy observed with use of MEK and RAF inhibitors in MAP2K1 - and ARAF-mutated, non-LCH patients further supports the central role of targeting the MAPK pathway in these tumors. The discovery of the discussed mutations and fusions in diverse kinases provides critical new insights into the genetic events central to a spectrum of adult and pediatric histiocytic neoplasms. Figure 1. Figure 1. Disclosures Off Label Use: This abstract describes use of MEK inhibitors (both tremetinib and cobimetinib) as well as sorafenib for MEK1 and ARAF mutant histiocytosis. . Stephens:Foundation Medicine, Inc.: Employment, Equity Ownership. Miller:Foundation Medicine, Inc.: Employment, Equity Ownership. Ross:Foundation Medicine Inc.: Employment. Ali:Foundation Medicine Inc.: Employment. Hyman:Chugai Pharma: Consultancy; Biotherapeutics: Consultancy; Atara: Consultancy, Honoraria.

Molecular-Targeted Therapy for Childhood Brain Tumors: A Moving Target

2020 ◽  
Vol 35 (12) ◽  
pp. 791-798
Author(s):  
Roger J. Packer ◽  
Lindsay Kilburn
Keyword(s):  
Targeted Therapy ◽  
Brain Tumors ◽  
Targeted Therapies ◽  
Molecular Targeted Therapy ◽  
Target Genes ◽  
Single Agent ◽  
Braf V600e ◽  
Normal Brain ◽  
Childhood Brain Tumors ◽  
Molecular Targeted Therapies

Molecular-targeted therapy is an attractive therapeutic approach for childhood brain tumors. Unfortunately, with some notable exceptions, such treatment has not yet made a major impact on survival or for that matter quality-of-life for children with brain tumors. Limitations include the specificity of any single agent to inhibit the target, the presence of multiple genetic abnormalities within a tumor, the likely presence of escape mechanisms and the frequent use of molecular-targeted therapies in relatively biologically unselected patient populations. Despite these limitations, the MEK inhibitors and the BRAF V600E inhibitors have already demonstrated efficacy and are being compared to standard therapy in trials of treatment-naïve patients. There is also great enthusiasm for molecular-targeted therapies that target selective gene fusions. Given the plasticity of epigenetic changes, the targeting of epigenetic aberrations is also a promising avenue of therapy. Because molecular-targeted therapies frequently target genes and pathways that are critical in normal brain development, the acute, subacute long-term sequelae of molecular-targeted therapies need to be carefully monitored.

scholarly journals Mucosal Melanoma: Pathological Evolution, Pathway Dependency and Targeted Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Yanni Ma ◽  
Ronghui Xia ◽  
Xuhui Ma ◽  
Robert L. Judson-Torres ◽  
Hanlin Zeng
Keyword(s):  
Targeted Therapy ◽  
Mapk Pathway ◽  
Treatment Options ◽  
Mucosal Melanoma ◽  
Telomere Maintenance ◽  
Evolutionary Trajectories ◽  
Detection And Diagnosis ◽  
New Biomarkers ◽  
Rna Maturation ◽  
Therapy Strategies

Mucosal melanoma (MM) is a rare melanoma subtype that originates from melanocytes within sun-protected mucous membranes. Compared with cutaneous melanoma (CM), MM has worse prognosis and lacks effective treatment options. Moreover, the endogenous or exogenous risk factors that influence mucosal melanocyte transformation, as well as the identity of MM precursor lesions, are ambiguous. Consequently, there remains a lack of molecular markers that can be used for early diagnosis, and therefore better management, of MM. In this review, we first summarize the main functions of mucosal melanocytes. Then, using oral mucosal melanoma (OMM) as a model, we discuss the distinct pathologic stages from benign mucosal melanocytes to metastatic MM, mapping the possible evolutionary trajectories that correspond to MM initiation and progression. We highlight key areas of ambiguity during the genetic evolution of MM from its benign lesions, and the resolution of which could aid in the discovery of new biomarkers for MM detection and diagnosis. We outline the key pathways that are altered in MM, including the MAPK pathway, the PI3K/AKT pathway, cell cycle regulation, telomere maintenance, and the RNA maturation process, and discuss targeted therapy strategies for MM currently in use or under investigation.

Zanidatamab (ZW25) in HER2-expressing gastroesophageal adenocarcinoma (GEA): Results from a phase I study.

2021 ◽  
Vol 39 (3_suppl) ◽  
pp. 164-164
Author(s):  
Funda Meric-Bernstam ◽  
Erika P. Hamilton ◽  
Muralidhar Beeram ◽  
Diana L. Hanna ◽  
Anthony B. El-Khoueiry ◽  
...  
Keyword(s):  
Targeted Therapy ◽  
Phase 1 ◽  
Treatment Options ◽  
Single Agent ◽  
Growth Factor Receptor ◽  
Standard Of Care ◽  
Eligibility Criteria ◽  
Good Tolerability ◽  
Heavily Pretreated ◽  
Anti Tumor Activity

164 Background: For patients with human epidermal growth factor receptor 2 (HER2)-overexpressing GEA, trastuzumab in combination with chemotherapy is the only approved HER2-targeted therapy, and they have limited treatment options after progression. Zanidatamab, a HER2-targeted bispecific antibody, has shown durable anti-tumor activity with good tolerability in a range of HER2-expressing cancers. Methods: In this 3-part Phase 1 study (NCT02892123), zanidatamab (10 mg/kg QW, 20 mg/kg Q2W, or 30 mg/kg Q3W) is administered as a single agent (Parts 1 & 2; QW or Q2W) or in combination with chemotherapy (Part 3; Q2W or Q3W). Eligibility criteria includes GEA with HER2 expression as assessed by immunohistochemistry (IHC) 3+ or IHC 2+, progression after standard of care therapy, and measurable disease per RECIST 1.1 (Part 2 requirement only). Results: In Parts 1 and 2, 36 GEA patients have been treated with zanidatamab (QW [n = 5]; Q2W [n = 31]). In Part 3, 26 GEA patients have been treated (zanidatamab Q2W + (paclitaxel [n = 11] or capecitabine [n = 6]); zanidatamab Q3W + capecitabine [n = 9]). Conclusions: Zanidatamab, both as a single agent and in combination with chemotherapy, is well tolerated with promising and durable anti-tumor activity in heavily pretreated GEA patients (including prior HER2-targeted therapy). These data support further investigation of zanidatamab as a novel therapeutic for patients with HER2-expressing GEA. Clinical trial information: NCT02892123. [Table: see text]

Role of Galectin-3 in the activation of p-ERK and in resistance to radiotherapy in glioblastoma through the activation of p-ERK independent of Ras activity

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 11073-11073
Author(s):  
A. R. El-Jawahri ◽  
T. Lautenschlaeger ◽  
D. Patel ◽  
A. Chakravarti
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Control Cell ◽  
Annexin V ◽  
Treatment Resistance ◽  
Clonogenic Survival ◽  
Signaling Cascades ◽  
Galectin 3

11073 Background: There has been a growing interest in investigating the molecular mechanisms leading to treatment resistance in glioblastoma (GBM). The MAPK pathway has been shown to be involved in mediating treatment resistance. Galectin-3 (Gal3) is commonly overexpressed in astrocytic tumors of the brain and has been associated with adverse clinical outcomes. We investigated the role and mechanisms of Gal3 in mediating treatment resistance in GBM through modulating the MAPK pathway. Methods: We investigated Gal3 expression in GBM cell lines (U87, LN18, LN229). We created stable Gal3 knockdown cell lines (Gal3KD), ERK-knockdown (lentiviral shRNA) and constitutively active MEK(MEK2DD plasmid obtained from Dr. Brugge) cell lines. We then evaluated the radiosensitivity, apoptosis, and cell viability of control cell lines treated by non-targeting (NT) vectors as compared to Gal3KD, ERKKD and MEK2DD using clonogenic survival, Annexin V/PI apoptosis, COMET, and cell cycle assays. Signaling cascades were evaluated using Western blot and a GTP-ras pull down assay. Gal3 was also transiently knocked down in MEK2DD and NT cell lines and signaling cascades were analyzed using western blotting. Gal3 binding interactions were identified using co-immunoprecipitation. Results: Gal3 expression was induced in all GBM cell lines following irradiation. Gal3KD showed increased radiosensitivity similar to ERKKD as compared to controls with decreased clonogenic survival, increased DNA damage, increased apoptosis, and increased cell cycle arrest in G1 and G2, while MEK2DD showed enhanced radioresistance. Gal3KD showed reduced p-ERK at baseline followed by a minimal induction of p-ERK with irradiation as compared to controls which have a high level of p-ERK. Overall p-Akt, ERK and Ras-GTP levels were equivalent in Gal3KD and controls. When Gal3 was transiently knocked down in MEK2DD cell line, p-ERK was drastically reduced similar to controls. Gal3 co-immunoprecipitated with ERK. Conclusions: Our results suggest a possible direct novel interaction between Gal3 and ERK in GBMs that is essential for the expression of p-ERK and mediating treatment resistance in GBMs. No significant financial relationships to disclose.

scholarly journals MODL-17. SHP2 INHIBITORS SHOW ACTIVITY AGAINST NF1-DEFICIENT GLIOMAS AND ENHANCE MAPK PATHWAY INHIBITION IN BRAF-V600E MUTANT GLIOMAS

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii414-iii414
Author(s):  
Daniel Muldoon ◽  
Guisheng Zhao ◽  
Carly Batt ◽  
Mallika Singh ◽  
Theodore Nicolaides
Keyword(s):  
Cell Lines ◽  
Glioma Cell ◽  
Mapk Pathway ◽  
Single Agent ◽  
Glioma Cells ◽  
Braf V600e ◽  
Pediatric Glioma ◽  
Glioma Cell Lines ◽  
A375 Cells

Abstract INTRODUCTION Activation of the RAS-MAPK signaling cascade is common in pediatric gliomas. Based on the role of SHP2 in RAS pathway signaling, we hypothesized that NF1-deficient pediatric glioma models would respond to SHP2 inhibitor monotherapy whereas BRAF-V600E gliomas would not. However, we postulated that the latter would exhibit increased sensitivity to a BRAF inhibitor (BRAFi) in combination with SHP2i. Here we demonstrate that the SHP2 inhibitors SHP099 and RMC-4550 (SHP2i) show significant single-agent activity in vitro against NF1-deficient glioma cells and that the combination of RMC-4550 with BRAFi shows increased activity in BRAF-V600E glioma cells relative to the single-agents. METHODS Using a panel of NF1 mutant/deficient and BRAF-V600E mutant glioma cell lines we examined effects on cell viability and protein expression levels of total and phosphorylated MEK, ERK, and AKT. RESULTS LN229 and U87 NF1-deficient glioma cells are sensitive to SHP2i alone but not A375 cells (melanoma, BRAF-V600E). Additionally, we show that in multiple BRAF-V600E glioma cell lines BRAFi sensitivity increases when combined with a SHP2i. Immunoblots show decreased expression of pERK and pMEK in LN229 cells following SHP2i exposure, while A375 cells maintain MAPK pathway signaling. A sustained decrease in the expression of pERK after 24 hours was observed in BRAF-V600E glioma cells with BRAFi in combination with SHP2i, consistent with relief of feedback inhibition. In vivo studies using orthotopic xenograft models are underway. CONCLUSION SHP2i shows preclinical activity in vitro against NF1-deficient pediatric glioma cell lines as a single-agent and against BRAF-V600E gliomas in combination with BRAFi.

scholarly journals Immune-Checkpoint Inhibitors in Platinum-Resistant Ovarian Cancer

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1663
Author(s):  
Alice Indini ◽  
Olga Nigro ◽  
Csongor György Lengyel ◽  
Michele Ghidini ◽  
Angelica Petrillo ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Molecular Mechanisms ◽  
Checkpoint Inhibitors ◽  
Treatment Options ◽  
Single Agent ◽  
Clinical Trial Data ◽  
Parp Inhibitors ◽  
Platinum Resistance ◽  
Combination Strategies ◽  
Platinum Resistant

Platinum-resistant ovarian cancer (OC) has limited treatment options and is associated with a poor prognosis. There appears to be an overlap between molecular mechanisms responsible for platinum resistance and immunogenicity in OC. Immunotherapy with single agent checkpoint inhibitors has been evaluated in a few clinical trials with disappointing results. This has prompted exploration of immunotherapy combination strategies with chemotherapy, anti-angiogenics, poly (ADP-ribose) polymerase (PARP) inhibitors and other targeted agents. The role of immunotherapy in the treatment of platinum-resistant OC remains undefined. The aim of this review is to describe the immunobiology of OC and likely benefit from immunotherapy, discuss clinical trial data and biomarkers that warrant further exploration, as well as provide an overview of future drug development strategies.

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