azd-6244 and Skin-Neoplasms

The identification of driver mutations in melanoma has changed the field of cancer treatment. BRAF and NRAS mutations are predominant in melanoma and lead to overactivation of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways. Selective inhibitors targeting key effectors of the MAPK pathway have revolutionized the treatment of patients with advanced metastatic BRAF-mutant melanoma. However, resistance to therapy is almost universal and remains a major challenge in clinical care, with the majority of patients progressing within 1 year. Dissecting the mechanisms of resistance to targeted therapies may offer new insights into strategies for overcoming resistance. This review describes the efficacy of therapies targeting the MAPK and PI3K/AKT signaling pathways in melanoma, details the mechanisms contributing to drug resistance, and discusses current approaches to improving outcomes further. Cancer 2017;123:2118-29. © 2017 American Cancer Society.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; CTLA-4 Antigen; Drug Administration Schedule; Drug Resistance, Neoplasm; Humans; Immunotherapy; Indoles; Ipilimumab; MAP Kinase Kinase 1; Melanoma; Molecular Targeted Therapy; Niacinamide; Nivolumab; Phenylurea Compounds; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Programmed Cell Death 1 Receptor; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-akt; Pyrimidines; Quinazolines; Signal Transduction; Skin Neoplasms; Sorafenib; Sulfonamides; Vemurafenib

New treatments for metastatic melanoma work through distinct mechanisms: enhancing the immune response and blocking cellular proliferation. Agents that enhance the immune response include ipilimumab, pembrolizumb, and nivolumab; agents that block cellular proliferation include vemurafenib, dabrafenib, trametinib, cobimetinib, binimetinib, and selumetinib. The translational impact of laboratory discoveries has revolutionized management of metastatic melanoma and enhanced the prognosis of affected patients.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Azetidines; Benzimidazoles; Humans; Imidazoles; Immunologic Factors; Indoles; Ipilimumab; Melanoma; Molecular Targeted Therapy; Nivolumab; Oximes; Piperidines; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Pyridones; Pyrimidinones; Skin Neoplasms; Sulfonamides; Vemurafenib

Treatment options for wild-type BRAF melanoma patients remain limited. Selumetinib, a MEK 1/2 inhibitor, suppresses pERK levels independent of BRAF and NRAS mutation status, and combination with docetaxel has demonstrated synergy in xenograft models. The aim of this study was to assess the efficacy and safety of selumetinib plus docetaxel as first-line treatment in patients with wild-type BRAF advanced melanoma.. In this double-blind multicentre phase II trial patients with wild-type BRAF melanoma were randomized (1:1) to docetaxel with selumetinib or placebo. Docetaxel 75 mg/m(2) was administered intravenously every 3 weeks up to six cycles. Selumetinib 75 mg or placebo was given orally twice daily until disease progression or unacceptable toxicity. The primary end point was progression-free survival (PFS). Tumour NRAS mutation status was analysed retrospectively and correlated with treatment outcomes.. Eighty-three patients were randomized to docetaxel plus selumetinib (n = 41) or docetaxel plus placebo (n = 42). The PFS hazard ratio (HR) (selumetinib:placebo) was 0.75 [90% confidence interval (CI) 0.50-1.14; P = 0.130], with a median PFS of 4.23 months (90% CI 3.63-6.90) for docetaxel plus selumetinib and 3.93 months (90% CI 2.07-4.16) for docetaxel alone. There was no significant difference in overall survival. The objective response rate was 32% with selumetinib versus 14% with placebo (P = 0.059). In a retrospective subset analysis, NRAS mutation status did not affect significantly upon clinical outcomes in either arm. The combination of docetaxel and selumetinib could be administered effectively to patients with metastatic melanoma, although the combination was less well tolerated than docetaxel alone.. The combination of docetaxel with selumetinib showed no significant improvement in PFS compared with docetaxel alone, although more patients showed a response to combination therapy. We found no evidence to support using tumour NRAS mutation as a basis for selecting patients for combined MEK inhibitor and chemotherapy.. DOC-MEK (EudraCT no: 2009-018153-23).

Topics: Aged; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Disease-Free Survival; DNA Mutational Analysis; Docetaxel; Double-Blind Method; GTP Phosphohydrolases; Humans; Kaplan-Meier Estimate; Male; Melanoma; Membrane Proteins; Middle Aged; Proportional Hazards Models; Proto-Oncogene Proteins B-raf; Skin Neoplasms; Taxoids; Treatment Outcome

Patients with metastatic melanoma, 50% of whose tumours harbour a BRAF mutation, have a poor prognosis. Selumetinib, a MEK1/2 inhibitor, has shown antitumour activity in patients with BRAF-mutant melanoma and in preclinical models when combined with chemotherapy. This study was designed to look for a signal of improved efficacy by comparing the combination of selumetinib and dacarbazine with dacarbazine alone.. This double-blind, randomised, placebo-controlled phase 2 study investigated selumetinib plus dacarbazine versus placebo plus dacarbazine as first-line treatment in patients older than 18 years with histologically or cytologically confirmed advanced BRAF-mutant cutaneous or unknown primary melanoma. Patients were randomly assigned by central interactive voice response system (1:1 ratio, block size four) to take either oral selumetinib (75 mg twice daily in a 21-day cycle) or placebo; all patients received intravenous dacarbazine (1000 mg/m(2) on day 1 of a 21-day cycle). Patients, investigators, and the study team were masked to the treatment assigned. The primary endpoint was overall survival analysed by intention to treat. This study is registered at ClinicalTrials.gov, NCT00936221.. Between July 20, 2009, and April 8, 2010, 91 patients were randomly assigned to receive dacarbazine in combination with selumetinib (n=45) or placebo (n=46). Overall survival did not differ significantly between groups (median 13·9 months, 80% CI 10·2-15·6, in the selumetinib plus dacarbazine group and 10·5 months, 9·6-14·7, in the placebo plus dacarbazine group; hazard ratio [HR] 0·93, 80% CI 0·67-1·28, one-sided p=0·39). However, progression-free survival was significantly improved in the selumetinib plus dacarbazine group versus the placebo plus dacarbazine group (HR 0·63, 80% CI 0·47-0·84, one-sided p=0·021), with a median of 5·6 months (80% CI 4·9-5·9) versus 3·0 months (2·8-4·6), respectively. The most frequent adverse events included nausea (28 [64%] of 44 patients on selumetinib vs 25 [56%] of 45 on placebo), acneiform dermatitis (23 [52%] vs one [2%]), diarrhoea (21 [48%] vs 13 [29%]), vomiting (21 [48%] vs 15 [33%]), and peripheral oedema (19 [43%] vs three [7%]). The most common grade 3-4 adverse event was neutropenia (six [14%] patients in the selumetinib plus dacarbazine group vs four [9%] in the placebo plus dacarbazine group).. Selumetinib plus dacarbazine showed clinical activity in patients with BRAF-mutant cutaneous or unknown primary melanoma, reflected by a significant benefit in progression-free survival compared with placebo plus dacarbazine group, although no significant change in overall survival was noted. The tolerability of this combination was generally consistent with monotherapy safety profiles.. AstraZeneca.

Topics: Adult; Aged; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Brazil; Dacarbazine; Disease-Free Survival; DNA Mutational Analysis; Double-Blind Method; Drug Administration Schedule; Europe; Female; Genetic Predisposition to Disease; Humans; Kaplan-Meier Estimate; Logistic Models; Male; Melanoma; Middle Aged; Mutation; Neoplasms, Unknown Primary; Phenotype; Proportional Hazards Models; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Skin Neoplasms; Time Factors; Treatment Outcome; United States

The high prevalence of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) and neuroblastoma v-ras oncogene homolog (NRAS) mutations in melanoma provides a strong rationale to test the clinical efficacy of mitogen-activated protein kinase kinase (MEK) inhibition in this disease. The authors hypothesized that the presence of BRAF or NRAS mutations would correlate with clinical benefit among patients who received treatment with combination regimens that included the MEK inhibitor selumetinib.. BRAF and NRAS mutation status was determined retrospectively in available tissue specimens from patients with melanoma who were enrolled in a phase 1 trial of selumetinib in combination with 1 of 4 drugs (dacarbazine, docetaxel, temsirolimus, or erlotinib). The clinical response rate and the time to progression (TTP) were assessed as a function of BRAF and NRAS mutation status.. Among 18 patients analyzed, 9 patients (50%) harbored a BRAF mutation (8 had a valine-to-glutamic acid substitution at residue 600 [V600E]; 1 had an arginine nonsense mutation at residue 603 [R603]), 4 patients (22%) harbored an NRAS mutation (2 had a glutamine-to-arginine substitution at residue 61 [Q61R], 1 had a glutamine-to-lysine substitution at residue 61 [Q61K], and 1 had a glycine-to-lysine substitution at residue 12 [G12S]), and 5 patient (28%) had the wild type of both genes. These mutations were mutually exclusive. Among the 9 patients who had BRAF mutations, 5 patients (56%) achieved a partial response, and 4 patients (44%) achieved stable disease for at least 6 weeks. No patient with the wild-type BRAF gene achieved a clinical response (P = .01 vs patients with BRAF mutations). The presence of an NRAS mutation did not correlate with the clinical response rate. The presence of a BRAF mutation was correlated significantly with the TTP in a multivariate model (hazard ratio, 0.22; P = .02 vs wild-type BRAF).. Higher response rates and longer TTP were observed with selumetinib-containing regimens in patients who had tumors that harbored a BRAF mutation compared with patients who had wild-type BRAF.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Enzyme Inhibitors; Female; Humans; Male; MAP Kinase Kinase Kinases; Melanoma; Middle Aged; Multivariate Analysis; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras); Skin Neoplasms; Treatment Outcome

Raf/mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK signaling pathway is constitutively activated in melanoma. AZD6244 blocks MEK1/2, inhibiting ERK phosphorylation. We focus on associated cutaneous toxicity and we attempt to understand the underlying pathophysiology and design treatment strategies.. Dermatologic conditions of 22 patients with unresectable melanoma stage III/IV in a phase II trial were evaluated. Thirteen patients received AZD6244 initially, and nine patients were treated with AZD6244 following tumor progression with temozolomide. Biopsies were compared with matched controls in normal skin. Immunohistochemistry was performed. Half-side treatment of acute skin toxicity compared therapeutic options.. Nineteen of 22 (86%) AZD6244-treated patients presented with cutaneous eruptions. Seventeen patients (77%) developed acute papulopustular rash. Chronic skin changes included xerosis, paronychia, and fissured fingertips, resembling cutaneous toxicity of epidermal growth factor receptor inhibition. In addition, we observed reduced pigmentation of hair and skin. Histology of acute skin lesions revealed a significant increase of apoptotic keratinocytes (P = 0.0008), focal neutrophilic infiltrates, destruction of the adnexal structures by neutrophils, and reduced cytokeratins. A significant proliferation shift from basal to suprabasal keratinocytes was shown in acute and chronic lesions. The number and viability of melanocytes was not affected. Corticosteroids plus antibacterial topical therapy ameliorate acute skin toxicity.. AZD6244-associated skin reactions partly overlap with those observed upon epidermal growth factor receptor inhibition. Additionally, pigmentation of skin and hair is affected. The interruption of the MEK signaling pathway results in an acute keratinocyte stress response with disturbed epidermal homeostasis, inflammation, and tissue damage. Chronic adaptation controls inflammatory tissue damage but leads to cutaneous malfunctions that explain chronic skin toxicity.

Topics: Adult; Apoptosis; Benzimidazoles; Drug Eruptions; Exanthema; Extracellular Signal-Regulated MAP Kinases; Female; Homeostasis; Humans; Keratinocytes; Male; Melanoma; Middle Aged; Mitogen-Activated Protein Kinases; Pigmentation Disorders; Protein Kinase Inhibitors; Skin Neoplasms

This study investigated the potential clinical utility of circulating free DNA (cfDNA) as a source of BRAF mutation detection in patients enrolled into a phase II study of AZD6244, a specific MEK1/2 inhibitor, in patients with advanced melanoma.. BRAF mutations were detected using Amplification Refractory Mutation System allele-specific PCR. BRAF mutation status was assessed in serum-derived cfDNA from 126 patients enrolled into the study and from 94 matched tumour samples.. Of 94 tumour samples, 45 (47.9%) were found to be BRAF mutation positive (BRAF+). Serum-derived cfDNA was BRAF+ in 33 of 126 (26.2%) samples, including in five samples for which tumour data were unavailable. Of BRAF+ tumours, 25 of 45 (55.6%) were BRAF+ in cfDNA. In three cases in which the tumour was negative, cfDNA was BRAF+. Progression-free survival (PFS) of patients with BRAF+ tumour and cfDNA was not significantly different compared with tumour BRAF+ but cfDNA BRAF-negative patients, indicating that cfDNA BRAF detection is not associated with poorer prognosis on PFS in stage III/IV advanced melanoma.. These data demonstrate the feasibility of BRAF mutation detection in cfDNA of patients with advanced melanoma. Future studies should aim to incorporate BRAF mutation testing in cfDNA to further validate this biomarker for patient selection.

Topics: Antineoplastic Agents; Benzimidazoles; Cell Line, Tumor; Disease-Free Survival; DNA Mutational Analysis; DNA, Neoplasm; HT29 Cells; Humans; Melanoma; Mutation; Prognosis; Proto-Oncogene Proteins B-raf; Skin Neoplasms

Genotyping of melanomas is used to identify patients for treatment with BRAF and MEK inhibitors, but clinical responses are highly variable. This study investigated the utility of protein expression phenotyping to provide an integrated assessment of gene expression programs in BRAF/NRAS melanoma which would be useful for prognosis and may predict response to MEK inhibition.. Mass spectrometry profiling of early passage cell lines established from Stage III cutaneous melanomas was conducted. Basal protein expression was correlated with in vitro response to the MEK inhibitor, selumetinib. Protein expression in a cohort of 32 drug naïve BRAF/NRAS metastatic melanoma specimens was examined. The prognostic utility of a subset of these proteins and mRNA transcripts from a separate cohort was determined.. Unsupervised analysis of basal cell line protein abundances delineated response to selumetinib, but BRAF/NRAS genotype did not. Resistance was associated with functions including cell motility, cell adhesion and cytoskeletal organization. Several of these response biomarkers were observed in lymph node biospecimens and correlated with melanoma-specific survival. Loss of ICAM-1 protein and mRNA expression was a strong prognosticator of diminished survival in BRAF/NRAS mutant melanoma.. These results demonstrate the utility of proteomic phenotyping to identify both putative biomarkers of response to MEK inhibition and prognostication associated with metastatic melanoma.

Topics: Benzimidazoles; Cell Line, Tumor; Chromatography, Liquid; Cohort Studies; Female; GTP Phosphohydrolases; Humans; Intercellular Adhesion Molecule-1; Male; Melanoma; Melanoma, Cutaneous Malignant; Membrane Proteins; Mutation; Neoplasm Staging; Prognosis; Protein Kinase Inhibitors; Proteomics; Proto-Oncogene Proteins B-raf; Skin Neoplasms; Survival Analysis; Tandem Mass Spectrometry

MEK inhibitors are being evaluated in clinical trials for treatment of different malignant neoplasms; trametinib dimethyl sulfoxide was approved by the US Food and Drug Administration for melanoma in 2013. We present 3 cases of patients receiving MEK inhibitors who developed an atypical eruption.. Three patients who were receiving different MEK inhibitors (selumetinib, cobimetinib, and trametinib) developed an eruption, all associated with unique duskiness. Drug hypersensitivity was confirmed by histopathologic testing in 2 of the 3 cases. The skin eruption responded well to corticosteroids and did not recur when treatment with the MEK inhibitor was restarted in 2 of the patients.. The typical skin reaction associated with MEK inhibitors is a papulopustular eruption. To our knowledge, the dusky erythema that occurred in the 3 patients described here has not previously been reported for this drug class.

Topics: Adult; Azetidines; Benzimidazoles; Drug Eruptions; Erythema; Female; Glucocorticoids; Humans; Male; Melanoma; Middle Aged; Mitogen-Activated Protein Kinase Kinases; Piperidines; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; Skin Neoplasms

BRAF inhibitors have revolutionized treatment of mutant BRAF metastatic melanomas. However, resistance develops rapidly following BRAF inhibitor treatment. We have found that BRAF-mutant melanoma cell lines are more sensitive than wild-type BRAF cells to the small molecule tyrosine kinase inhibitor dovitinib. Sensitivity is associated with inhibition of a series of known dovitinib targets. Dovitinib in combination with several agents inhibits growth more effectively than either agent alone. These combinations inhibit BRAF-mutant melanoma and colorectal carcinoma cell lines, including cell lines with intrinsic or selected BRAF inhibitor resistance. Hence, combinations of dovitinib with second agents are potentially effective therapies for BRAF-mutant melanomas, regardless of their sensitivity to BRAF inhibitors.

Topics: Animals; Benzimidazoles; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Drug Synergism; Humans; Indoles; Male; Melanoma; Melanoma, Cutaneous Malignant; Mice, Nude; Mutation; Neoplasm Proteins; Protein Kinase Inhibitors; Quinolones; Signal Transduction; Skin Neoplasms; Small Molecule Libraries; Sulfonamides; Vemurafenib

Development of small molecular inhibitors against BRAF and MEK has been a breakthrough in the treatment of malignant melanoma. However, the long-term effect is foiled in virtually all patients by the emergence of resistant tumor cell populations. Therefore, mechanisms resulting in the acquired resistance against BRAF and MEK inhibitors have gained much attention and several strategies have been proposed to overcome tumor resistance, including interval treatment or withdrawal of these compounds after disease progression.. Using a panel of cell lines with an acquired resistance against MEK inhibitors, we have evaluated the sensitivity of these cells against compounds targeting AKT/mTOR signaling, as well as novel ERK1/2 inhibitors. Furthermore, the effects of withdrawal of MEK inhibitor on migration in resistant cell lines were analyzed.. We demonstrate that withdrawal of BRAF or MEK inhibitors in tumor cells with an acquired resistance results in reactivation of ERK1/2 signaling and upregulation of EMT-inducing transcription factors, leading to a highly migratory and invasive phenotype of cancer cells. Furthermore, we show that migration in these cells is independent from AKT/mTOR signaling. However, combined targeting of AKT/mTOR using MK-2206 and AZD8055 efficiently inhibits proliferation in all resistant tumor cell lines analyzed.. We propose that combined targeting of MEK/AKT/mTOR or treatment with a novel ERK1/2 inhibitor downstream of BRAF/MEK suppresses proliferation as well as migration and invasion in resistant tumor cells. We provide a rationale against the discontinuation of BRAF or MEK inhibitors in patients with an acquired resistance, and provide a rationale for combined targeting of AKT/mTOR and MEK/ERK1/2, or direct targeting of ERK1/2 as an effective treatment strategy.

Topics: Benzimidazoles; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p27; Drug Resistance, Neoplasm; Extracellular Signal-Regulated MAP Kinases; HCT116 Cells; Heterocyclic Compounds, 3-Ring; HT29 Cells; Humans; Melanoma; Melanoma, Cutaneous Malignant; Mitogen-Activated Protein Kinase Kinases; Morpholines; Neoplasm Invasiveness; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6; Signal Transduction; Skin Neoplasms; TOR Serine-Threonine Kinases

We report on whole-exome sequencing (WES) of 213 melanomas. Our analysis established NF1, encoding a negative regulator of RAS, as the third most frequently mutated gene in melanoma, after BRAF and NRAS. Inactivating NF1 mutations were present in 46% of melanomas expressing wild-type BRAF and RAS, occurred in older patients and showed a distinct pattern of co-mutation with other RASopathy genes, particularly RASA2. Functional studies showed that NF1 suppression led to increased RAS activation in most, but not all, melanoma cases. In addition, loss of NF1 did not predict sensitivity to MEK or ERK inhibitors. The rebound pathway, as seen by the induction of phosphorylated MEK, occurred in cells both sensitive and resistant to the studied drugs. We conclude that NF1 is a key tumor suppressor lost in melanomas, and that concurrent RASopathy gene mutations may enhance its role in melanomagenesis.

Topics: Antineoplastic Agents; Benzimidazoles; DNA Mutational Analysis; Drug Resistance, Neoplasm; Exome; Genetic Association Studies; Genetic Predisposition to Disease; Humans; Inhibitory Concentration 50; Kaplan-Meier Estimate; Loss of Heterozygosity; Male; Melanoma; Mutation, Missense; Neurofibromin 1; ras Proteins; Sequence Analysis, RNA; Skin Neoplasms; Sunlight; Tumor Cells, Cultured

Melanoma is a devastating form of skin cancer with limited therapeutic options. Fifteen to 20% of patients with melanoma have an activating mutation in the GTPase, NRAS. The major downstream effectors of RAS are RAFs (ARAF, BRAF, and CRAF), phosphoinositide 3-kinase (PI3K), and the Ral guanine exchange factors (RalGEF). TANK-binding kinase 1 (TBK1) is an atypical IκB kinase family member that acts downstream of RalGEFs. Whereas many studies have analyzed RAF and PI3K signaling in mutant NRAS melanoma, the role of RalGEF/Ral is understudied and TBK1 has not been examined. To address this, TBK1 was modulated with knockdown approaches and targeted therapies to determine the role of TBK1 in motility, apoptosis, and signaling. In melanoma, NRAS overexpression increased TBK1 phosphorylation. TBK1 depletion inhibited migration and invasion, whereas its constitutive overexpression led to an increase in invasion. In three-dimensional systems that mimic the dermal microenvironment, TBK1 depletion or inhibition cooperated with MEK inhibitors to promote apoptosis, particularly in the context of MEK-insensitive mutant NRAS. This effect was absent in melanoma cells that are wild-type for NRAS. These results suggest the utility of TBK1 inhibitors as part of a treatment regimen for patients with mutant NRAS melanoma, for whom there are no current effective therapies.. TBK1 promotes the malignant properties of NRAS-mutant melanoma and its targeting, in combination with MEK, promotes apoptosis, thus providing a potential novel targeted therapeutic option.

Topics: Apoptosis; Benzimidazoles; Cell Line, Tumor; Cell Movement; Drug Resistance, Neoplasm; Gene Knockdown Techniques; GTP Phosphohydrolases; Humans; Melanoma; Membrane Proteins; Mitogen-Activated Protein Kinase Kinases; Molecular Targeted Therapy; Mutation; Neoplasm Invasiveness; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Pyrimidines; Skin Neoplasms; Thiophenes

Selumetinib plus dacarbazine prolongs progression-free survival in BRAF-mutant melanoma.

Topics: Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Dacarbazine; Disease-Free Survival; Humans; Melanoma; Mutation; Proto-Oncogene Proteins B-raf; Skin Neoplasms

In melanoma, the RAS/RAF/MEK/ERK pathway is frequently activated by mutations in BRAF and NRAS. Selumetinib (AZD6244) is an oral, selective, non-ATP-competitive inhibitor of MEK1/2. Here, we describe a patient with metastatic melanoma (T1N2cM1a) with a BRAF V600E mutation. She is currently being treated with selumetinib 75 mg twice daily in a phase I trial and has shown complete response for the past 4 years. This case report raises questions regarding treatment schedule, treatment duration and management of adverse events.

Topics: Adult; Antineoplastic Agents; Benzimidazoles; Disease-Free Survival; Female; Head and Neck Neoplasms; Humans; MAP Kinase Kinase 1; MAP Kinase Kinase 2; Melanoma; Proto-Oncogene Proteins B-raf; Skin Neoplasms; Thoracic Neoplasms

The majority of melanomas show constitutive activation of the RAS-RAF-MAP/ERK kinase (MEK)-mitogen-activated protein kinase (MAPK) pathway. AZD6244 is a selective MEK1/2 inhibitor that markedly reduces tumor P-MAPK levels, but it produces few clinical responses in melanoma patients. An improved understanding of the determinants of resistance to AZD6244 may lead to improved patient selection and effective combinatorial approaches. The effects of AZD6244 on cell growth and survival were tested in a total of 14 Braf-mutant and 3 wild-type human cutaneous melanoma cell lines. Quantitative assessment of phospho-protein levels in the Braf-mutant cell lines by reverse phase protein array (RPPA) analysis showed no significant association between P-MEK or P-MAPK levels and AZD6244 sensitivity, but activation-specific markers in the phosphoinositide 3-kinase (PI3K)-AKT pathway correlated with resistance. We also identified resistant cell lines without basal activation of the PI3K-AKT pathway. RPPA characterization of the time-dependent changes in signaling pathways revealed that AZD6244 produced durable and potent inhibition of P-MAPK in sensitive and resistant Braf-mutant cell lines, but several resistant lines showed AZD6244-induced activation of AKT. In contrast, sensitive cell lines showed AZD6244 treatment-induced upregulation of PTEN protein and mRNA expression. Inhibition of AKT, TORC1/2, or insulin-like growth factor I receptor blocked AZD6244-induced activation of AKT and resulted in synergistic cell killing with AZD6244. These findings identify basal and treatment-induced regulation of the PI3K-AKT pathway as a critical regulator of AZD6244 sensitivity in Braf-mutant cutaneous melanoma cells and the novel regulation of PTEN expression by AZD6244 in sensitive cells, and suggest new combinatorial approaches for patients.

Topics: Apoptosis; Benzimidazoles; Blotting, Western; Cell Proliferation; Extracellular Signal-Regulated MAP Kinases; Humans; Melanoma; Mutation; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Small Interfering; Signal Transduction; Skin Neoplasms; Tumor Cells, Cultured

Melanoma is relatively resistant to chemotherapy; improved targeting of molecules critical for cell proliferation and survival are needed. Phosphatidylinositol-3 kinase (PI3K) is an important target in melanoma; however, activity of PI3K inhibitors (PI3KI) is limited. Our purpose was to assess mTOR as a cotarget for PI3K.. Using a method of quantitative immunofluorescence to measure mTOR expression in a large melanoma cohort, we studied associations with PI3K subunits, p85 and p110α. We assessed addition of the mTOR inhibitor rapamycin to 2 PI3KIs, NVP-BKM120 and LY294002. We studied in vitro activity of a novel dual PI3K/mTOR inhibitor NVP-BEZ235 and activity of the combination of NVP-BEZ235 and the MAP/ERK kinase (MEK) inhibitor AZD6244.. Strong coexpression of mTOR and p110α was observed (ρ = 0.658; P < 0.0001). Less coexpression was seen with p85 (ρ = 0.239; P < 0.0001). Strong synergism was shown between rapamycin and both PI3KIs. Activity of both PI3KIs was similarly enhanced with all rapamycin concentrations used. The dual PI3K/mTOR inhibitor effectively inhibited viability in 23 melanoma cell lines (IC(50) values in the nanomolar range), regardless of B-Raf mutation status, with resultant reduction in clonogenicity and downregulation of pAkt and pP70S6K. Synergism was seen when combining NVP-BEZ235 and AZD6244, with resultant increases in poly(ADP-ribose) polymerase and caspase-2 cleavage.. mTOR and p110α are coexpressed in melanoma. Rapamycin concentrations as low as 1 nmol/L enhance activity of PI3KIs. The dual PI3K/mTOR inhibitor NVP-BEZ235 is highly active in melanoma cells in vitro, suggesting that concurrent PI3K and mTOR targeting in melanoma warrants further investigation, both alone and in combination with MEK inhibitors.

Topics: Benzimidazoles; Cell Line, Tumor; Drug Evaluation, Preclinical; Drug Synergism; Humans; Imidazoles; Melanoma; Molecular Targeted Therapy; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Quinolines; Signal Transduction; Skin Neoplasms; Tissue Array Analysis; TOR Serine-Threonine Kinases