Evodiamine inhibits growth of vemurafenib drug-resistant melanoma via suppressing IRS4/PI3K/AKT signaling pathway.

Evodiamine, a novel alkaloid, was isolated from the fruit of tetradium. It exerts a diversity of pharmacological effects and has been used to treat gastropathy, hypertension, and eczema. Several studies reported that evodiamine has various biological effects, including anti-nociceptive, anti-bacterial, anti-obesity, and anti-cancer activities. However, there is no research regarding its effects on drug-resistant cancer. This study aimed to investigate the effect of evodiamine on human vemurafenib-resistant melanoma cells (A375/R cells) proliferation ability and its mechanism. Cell activity was assessed using the cell counting kit-8 (CCK-8) method. Flow cytometry assay was used to assess cell apoptosis and cell cycle. A xenograft model was used to analyze the inhibitory effects of evodiamine on tumor growth. Bioinformatics analyses, network pharmacology, and molecular docking were used to explore the potential mechanism of evodiamine in vemurafenib-resistant melanoma. RT-qPCR and Western blotting were performed to reveal the molecular mechanism. The alkaloid extract of the fruit of tetradium, evodiamine showed the strongest tumor inhibitory effect on vemurafenib-resistant melanoma cells compared to treatment with vemurafenib alone. Evodiamine inhibited vemurafenib-resistant melanoma cell growth, proliferation, and induced apoptosis, conforming to a dose-effect relationship and time-effect relationship. Results from network pharmacology and molecular docking suggested that evodiamine might interact with IRS4 to suppress growth of human vemurafenib-resistant melanoma cells. Interestingly, evodiamine suppressed IRS4 expression and then inhibited PI3K/AKT signaling pathway, and thus had the therapeutic action on vemurafenib-resistant melanoma.

Vemurafenib induces senescence in acute myeloid leukemia and myelodysplastic syndrome by activating the HIPPO signaling pathway: implications for potential targeted therapy.

BACKGROUND: The outcome of Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) remain dismal despite the development of treatment. Targeted therapy is gaining more and more attention in improving prognosis. METHODS: Expression of BRAF was analyzed by RT-qPCR in AML and MDS patients. Cells viability treated by drugs was measured by CCK-8 assay. Network pharmacology and RNA-sequence were used to analyze the mechanism of drugs and verified in vitro and xenograft tumor model. RESULTS: Here we showed that BRAF was overexpressed in AML and MDS patients, and correlated with poor prognosis. The BRAF inhibitor-Vemurafenib (VEM) could significantly induce senescence, proliferation inhibition and apoptosis in AML cells, which can be enhanced by Bortezomib (BOR). This inhibitory effect was also verified in CD34 + cells derived from AML patients. Mechanistically, we showed that VEM combined with BOR could turn on HIPPO signaling pathway, thereby inducing cellular senescence in AML cells and xenograft mouse. CONCLUSIONS: Taken together, our findings demonstrate a significant upregulation of BRAF expression in AML and MDS patients, which is associated with unfavorable clinical outcomes. We also discovered that the BRAF inhibitor Vemurafenib induces cellular senescence through activation of the HIPPO signaling pathway. Analysis of BRAF expression holds promise as a prognostic indicator and potential therapeutic target for individuals with AML and MDS.

Vitamin D Modulates the Response of Patient-Derived Metastatic Melanoma Cells to Anticancer Drugs.

Melanoma is considered a lethal and treatment-resistant skin cancer with a high risk of recurrence, making it a major clinical challenge. Our earlier studies documented that 1,25(OH)2D3 and its low-calcaemic analogues potentiate the effectiveness of dacarbazine and cediranib, a pan-VEGFR inhibitor. In the current study, a set of patient-derived melanoma cultures was established and characterised as a preclinical model of human melanoma. Thus, patient-derived cells were preconditioned with 1,25(OH)2D3 and treated with cediranib or vemurafenib, a BRAF inhibitor, depending on the BRAF mutation status of the patients enrolled in the study. 1,25(OH)2D3 preconditioning exacerbated the inhibition of patient-derived melanoma cell growth and motility in comparison to monotherapy with cediranib. A significant decrease in mitochondrial respiration parameters, such as non-mitochondrial oxygen consumption, basal respiration and ATP-linked respiration, was observed. It seems that 1,25(OH)2D3 preconditioning enhanced cediranib efficacy via the modulation of mitochondrial bioenergetics. Additionally, 1,25(OH)2D3 also decreased the viability and mobility of the BRAF+ patient-derived cells treated with vemurafenib. Interestingly, regardless of the strict selection, cancer-derived fibroblasts (CAFs) became the major fraction of cultured cells over time, suggesting that melanoma growth is dependent on CAFs. In conclusion, the results of our study strongly emphasise that the active form of vitamin D, 1,25(OH)2D3, might be considered as an adjuvant agent in the treatment of malignant melanoma.

Carotenoids from Marine Microalgae as Antimelanoma Agents.

Melanoma cells are highly invasive and metastatic tumor cells and commonly express molecular alterations that contribute to multidrug resistance (e.g., BRAFV600E mutation). Conventional treatment is not effective in a long term, requiring an exhaustive search for new alternatives. Recently, carotenoids from microalgae have been investigated as adjuvant in antimelanoma therapy due to their safety and acceptable clinical tolerability. Many of them are currently used as food supplements. In this review, we have compiled several studies that show microalgal carotenoids inhibit cell proliferation, cell migration and invasion, as well as induced cell cycle arrest and apoptosis in various melanoma cell lines. MAPK and NF-ĸB pathway, MMP and apoptotic factors are frequently affected after exposure to microalgal carotenoids. Fucoxanthin, astaxanthin and zeaxanthin are the main carotenoids investigated, in both in vitro and in vivo experimental models. Preclinical data indicate these compounds exhibit direct antimelanoma effect but are also capable of restoring melanoma cells sensitivity to conventional chemotherapy (e.g., vemurafenib and dacarbazine).

Therapeutic Efficacy of Pharmacological Ascorbate on Braf Inhibitor Resistant Melanoma Cells In Vitro and In Vivo.

High-dose ascorbate paradoxically acts as a pro-oxidant causing the formation of hydrogen peroxide in an oxygen dependent manner. Tumor cells (in particular melanoma cells) show an increased vulnerability to ascorbate induced reactive oxygen species (ROS). Therefore, high-dose ascorbate is a promising pharmacological approach to treating refractory melanomas, e.g., with secondary resistance to targeted BRAF inhibitor therapy. BRAF mutated melanoma cells were treated with ascorbate alone or in combination with the BRAF inhibitor vemurafenib. Viability, cell cycle, ROS production, and the protein levels of phospho-ERK1/2, GLUT-1 and HIF-1α were analyzed. To investigate the treatment in vivo, C57BL/6NCrl mice were subcutaneously injected with D4M.3A (BrafV600E) melanoma cells and treated with intraperitoneal injections of ascorbate with or without vemurafenib. BRAF mutated melanoma cell lines either sensitive or resistant to vemurafenib were susceptible to the induction of cell death by pharmacological ascorbate. Treatment of BrafV600E melanoma bearing mice with ascorbate resulted in plasma levels in the pharmacologically active range and significantly improved the therapeutic effect of vemurafenib. We conclude that intravenous high-dose ascorbate will be beneficial for melanoma patients by interfering with the tumor's energy metabolism and can be safely combined with standard melanoma therapies such as BRAF inhibitors without pharmacological interference.

uPAR Controls Vasculogenic Mimicry Ability Expressed by Drug-Resistant Melanoma Cells.

Malignant melanoma is a highly aggressive skin cancer characterized by an elevated grade of tumor cell plasticity. Such plasticity allows adaptation of melanoma cells to different hostile conditions and guarantees tumor survival and disease progression, including aggressive features such as drug resistance. Indeed, almost 50% of melanoma rapidly develop resistance to the BRAFV600E inhibitor vemurafenib, with fast tumor dissemination, a devastating consequence for patients outcomes. Vasculogenic mimicry (VM), the ability of cancer cells to organize themselves in perfused vascular-like channels, might sustain tumor spread by providing vemurafenib-resistant cancer cells with supplementary ways to enter into circulation and disseminate. Thus, this research aims to determine if vemurafenib resistance goes with the acquisition of VM ability by aggressive melanoma cells, and identify a driving molecule for both vemurafenib resistance and VM. We used two independent experimental models of drug-resistant melanoma cells, the first one represented by a chronic adaptation of melanoma cells to extracellular acidosis, known to drive a particularly aggressive and vemurafenib-resistant phenotype, the second one generated with chronic vemurafenib exposure. By performing in vitro tube formation assay and evaluating the expression levels of the VM markers EphA2 and VE-cadherin by Western blotting and flow cytometer analyses, we demonstrated that vemurafenib-resistant cells obtained by both models are characterized by an increased ability to perform VM. Moreover, by exploiting the CRISPR-Cas9 technique and using the urokinase plasminogen activator receptor (uPAR) inhibitor M25, we identified uPAR as a driver of VM expressed by vemurafenib-resistant melanoma cells. Thus, uPAR targeting may be successfully leveraged as a new complementary therapy to inhibit VM in drug-resistant melanoma patients, to counteract the rapid progression and dissemination of the disease.

Eficacia y seguridad de vemurafenib más cobimetinib para el tratamiento de pacientes adultos con melanoma maligno avanzado o metastásico, con mutacion BRAF V600E, inoperable y con ECOG 0-1 / Efficacy and safety of vemurafenib plus cobimetinib for the treatment of adult patients with advanced or metastatic malignant melanoma, with BRAF V600E mutation, inoperable and with ECOG 0-1

INTRODUCCIÓN: El melanoma maligno (MM), es un tipo de cáncer de piel agresivo que afecta a los melanocitos. El MM representa solo el 4 % de los tumores malignos de la piel, pero es el responsable del 80 % de las muertes por estos tumores. Actualmente, la quimioterapia se usa con menos frecuencia que la inmunoterapia o la terapia dirigida. La inmunoterapia inhibe la proteína PD-1; y la terapia dirigida inhibe la proteína mutada BRAF y las proteínas quinasas MEK. A diferencia de la inmunoterapia (que puede usarse para todos los pacientes con MM metastásico), la terapia dirigida está indicada solo para aquellos pacientes con la mutación BRAF V600. La mutación BRAF está presente en el 50 % de los casos de MM y el 70 % de las mutaciones BRAF son de tipo V600E. En EsSalud, los pacientes adultos con MM avanzado o metastásico, con mutación BRAF V600E, inoperable y con ECOG 0-1 disponen de la inmunoterapia (nivolumab) y la quimioterapia como tratamientos de primera línea. No obstante, los especialistas en oncología señalan que la terapia dirigida podría ser más eficaz, en aquellos con la mutación BRAF V600E, que las opciones disponibles en EsSalud. De esta forma, sugieren el uso de vemurafenib más cobimetinib (V+C) como tratamiento de primera línea para estos pacientes. OBJETIVO: El objetivo del presente dictamen fue evaluar la eficacia y seguridad de V+C, comparado con nivolumab o quimioterapia, para el tratamiento de pacientes adultos con MM avanzado o metastásico, con mutación BRAF V600E, inoperable y con ECOG 0-1. METODOLOGÍA: Tras la búsqueda de la evidencia, se incluyeron cinco guías de práctica clínica (GPC) elaboradas por la National Comprehensive Cancer Network (NCCN), la American Society of Clinical Oncology (ASCO), el Cancer Council Australia (CCA), la European Society for Medical Oncology (ESMO) y la Scottish Intercollegiate Guidelines Network (SIGN); tres evaluaciones de tecnologías sanitarias (ETS) realizadas por el National Institute for Health and Care Excellence (NICE), la Canadian Agency for Drugs and Technologies in Health (CADTH) y el Institute for Quality and Efficiency in Healthcare (IQWiG); y dos revisiones sistemáticas con metaanálisis en red (RSMAR) desarrolladas por Zoratti et al. 2019 y Pike et al. 2017. RESULTADOS: Se llevó a cabo una búsqueda de evidencia científica con respecto al uso de V+C como tratamiento de primera línea en pacientes adultos con MM avanzado o metastásico, con mutación BRAF V600E, inoperable y con ECOG 0-1. CONCLUSIONES: El presente dictamen preliminar tuvo por objetivo evaluar la mejor evidencia disponible sobre la eficacia y seguridad de V+C, comparado con nivolumab o quimioterapia, para el tratamiento de pacientes adultos con MM avanzado o metastásico, con mutación BRAF, inoperable y con ECOG 0-1. Los desenlaces de interés fueron SG, calidad de vida y eventos adversos. Tras la búsqueda de la literatura se identificaron cinco GPC elaboradas por NCCN, CCA, ASCO, ESMO y SIGN; tres ETS desarrolladas por NICE, CADTH e IQWiG. No se identificaron ECA o estudios observacionales comparativos que respondieran a la pregunta PICO. Por tal motivo, se optó por incluir dos estudios que evaluaron de manera indirecta (metaanálisis en red) V+C vs. nivolumab o quimioterapia (la RSMAR de Zoratti et al. 2019 y la RSMAR de Pike et al. 2017). Cuatro GPC (NCCN, ASCO, ESMO, CCA) de las cinco evaluadas recomiendan nivolumab o V+C; la guía restante (SIGN), solo nivolumab; y ninguna guia mencionó a la quimioterapia como tratamiento de primera línea. La ESMO recomienda a los inhibidores de PD-1(nivolumab) como el tratamiento estándar de primera línea para los pacientes con MM metastásico, además, la CCA y la ESMO señalaron que es preferible iniciar con anti PD-1 (nivolumab); sobre todo en pacientes con buen estado de salud y cuya enfermedad no progrese rápidamente. Las ETS fueron disimiles en sus recomendaciones. La CADTH condicionó su recomendación a la reducción en el precio del medicamento; IQWiG concluyó que existe beneficio adicional a favor de V+C; pero que la información sobre eventos adversos (EA) presenta limitaciones importantes. Por su parte NICE no recomendó el uso de V+C por no ser costo-efectivo. Es de destacar que las tres ETS no incluyen entre sus comparadores a nivolumab o quimioterapia, medicamentos que son alternativas disponibles y con las que se tienen experiencia de uso en EsSalud. Las RSMAR sugieren que V+C es similar a nivolumab en términos de SG y EA. Aunque sugieren diferencias a favor de V+C, en comparación con quimioterapia, las estimaciones indirectas no cumplieron con el criterio de transitividad y presentaron limitaciones que afectan su validez. Además, reportes más recientes muestran una alta incidencia de EA serios para V+C diferentes a los reportados por las RSMAR. Dado que la evidencia disponible no ha mostrado que la relación riesgo-beneficio sea favorable a V+C, en comparación con nivolumab o quimioterapia, la aprobación de uso de V+C en EsSalud no sería una decisión costo-oportuna; tomando en cuenta la disponibilidad del tratamiento con nivolumab, el cual fue aprobado al ser comparado con quimioterapia, eficaz y seguro, recomendado por guías internacionales, con el cual se tiene experiencia de uso y es menos costoso. Por lo expuesto, el IETSI no aprueba el uso de vemurafenib más cobimetinib para el tratamiento de pacientes adultos con melanoma maligno avanzado o metastásico, con mutación BRAF, inoperable y con ECOG 0-1.

Ocoxin Increases the Antitumor Effect of BRAF Inhibition and Reduces Cancer Associated Fibroblast-Mediated Chemoresistance and Protumoral Activity in Metastatic Melanoma.

Whereas the prevalence of several cancer types is decreasing, skin malignancies are growing more common every year. Malignant melanoma is the most aggressive form of skin cancer with high metastatic capacity. In most cases, malignant melanoma shows acquired therapy resistance. We evaluated the ability of Ocoxin, a natural compound-based antioxidant and anti-inflammatory nutritional complement, to exert an antitumor effect in melanoma. To do so, the cytotoxicity of Ocoxin in a panel of BRAF-mutated murine and human melanoma cell lines was tested alone and in combination with BRAF inhibitor Vemurafenib. Our results revealed a potent cytotoxic effect of Ocoxin against melanoma cells and a synergic effect when combined with Vemurafenib, reducing viability and increasing apoptosis. Besides, Ocoxin interferes with the cell cycle, impairs the inherent and fibroblast-mediated melanoma cell migration, and reduces resistance to BRAF inhibition. Proteomic analysis revealed reduced tumor secretion of inflammatory factors Galectin-1, Osteopontin, CCL5, and CCL9 upon treatment with Ocoxin. Moreover, RNASeq showed that Ocoxin downregulated the cell cycle and proliferation-related genes. In vivo, Ocoxin reduced the number of lung metastasis of YUMM-1.7 melanoma cells. Therefore, Ocoxin arises as a good candidate for clinical trials analyzing the beneficial effects in patients suffering from this cutaneous malignancy.

Dose-escalation study of vemurafenib with sorafenib or crizotinib in patients with BRAF-mutated advanced cancers.

BACKGROUND: BRAF inhibitors are effective in melanoma and other cancers with BRAF mutations; however, patients ultimately develop therapeutic resistance through the activation of alternative signaling pathways such as RAF/RAS or MET. The authors hypothesized that combining the BRAF inhibitor vemurafenib with either the multikinase inhibitor sorafenib or the MET inhibitor crizotinib could overcome therapeutic resistance. METHODS: Patients with advanced cancers and BRAF mutations were enrolled in a dose-escalation study (3 + 3 design) to determine the maximum tolerated dose (MTD) and the dose-limiting toxicities (DLTs) of vemurafenib with sorafenib (VS) or vemurafenib with crizotinib (VC). RESULTS: In total, 38 patients (VS, n = 24; VC, n = 14) were enrolled, and melanoma was the most represented tumor type (VS, 38%; VC, 64%). In the VS arm, vemurafenib 720 mg twice daily and sorafenib 400 mg am/200 mg pm were identified as the MTDs, DLTs included grade 3 rash (n = 2) and grade 3 hypertension, and partial responses were reported in 5 patients (21%), including 2 with ovarian cancer who had received previous treatment with BRAF, MEK, or ERK inhibitors. In the VC arm, vemurafenib 720 mg twice daily and crizotinib 250 mg daily were identified as the MTDs, DLTs included grade 3 rash (n = 2), and partial responses were reported in 4 patients (29%; melanoma, n = 3; lung adenocarcinoma, n = 1) who had received previous treatment with BRAF, MEK, and/or ERK inhibitors. Optional longitudinal collection of plasma to assess dynamic changes in circulating tumor DNA demonstrated the elimination of BRAF-mutant DNA from plasma during therapy (P = .005). CONCLUSIONS: Vemurafenib combined with sorafenib or crizotinib was well tolerated with encouraging activity, including among patients who previously received treatment with BRAF, MEK, or ERK inhibitors.

In vitro and in vivo identification of clinically approved drugs that modify ACE2 expression.

The COVID-19 pandemic caused by SARS-CoV-2 has is a global health challenge. Angiotensin-converting enzyme 2 (ACE2) is the host receptor for SARS-CoV-2 entry. Recent studies have suggested that patients with hypertension and diabetes treated with ACE inhibitors (ACEIs) or angiotensin receptor blockers have a higher risk of COVID-19 infection as these drugs could upregulate ACE2, motivating the study of ACE2 modulation by drugs in current clinical use. Here, we mined published datasets to determine the effects of hundreds of clinically approved drugs on ACE2 expression. We find that ACEIs are enriched for ACE2-upregulating drugs, while antineoplastic agents are enriched for ACE2-downregulating drugs. Vorinostat and isotretinoin are the top ACE2 up/downregulators, respectively, in cell lines. Dexamethasone, a corticosteroid used in treating severe acute respiratory syndrome and COVID-19, significantly upregulates ACE2 both in vitro and in vivo. Further top ACE2 regulators in vivo or in primary cells include erlotinib and bleomycin in the lung and vancomycin, cisplatin, and probenecid in the kidney. Our study provides leads for future work studying ACE2 expression modulators.

Vemurafenib may overcome TNF-related apoptosis-inducing ligand (TRAIL) resistance in anaplastic thyroid cancer cells.

PURPOSE: Anaplastic thyroid cancer (ATC) is rare but with poor prognosis. TRAIL can selectively induce apoptosis in cancer cells; however, resistance is quite common. Aim of our study was to evaluate TRAIL-induced apoptosis in ATC-derived cell lines, in vitro and in vivo, and the effect of combination with tyrosine kinase inhibitors (TKIs) selective for BRAF (vemurafenib) or Akt (MK-2206). METHODS: Four ATC-derived cell lines were used: C643, CAL62, HTh7, with activating mutation of RAS and copy gain of PI3K (HTh7) and, 8505C with activating mutation of BRAF. Cells were treated with TRAIL alone or in combination with vemurafenib or MK-2206. The pro-apoptotic effect of TRAIL alone or combined with TKIs was, also, evaluated in two mouse xenograft models (HTh7 and 8505C). RESULTS: C643, CAL62, and HTh7 cells were sensitive to TRAIL-induced apoptosis, whereas 8505C cells were resistant. Both in vitro and in vivo vemurafenib was able to increase the TRAIL-induced apoptosis in 8505C cells causing a slower tumor growth in 8505C xenograft compared to placebo, while MK-2206 did not have any additive effect on TRAIL treatment in HTh7 model. CONCLUSIONS: TRAIL is a promising therapeutic agent in ATC and in case of resistance vemurafenib may be a valid complementary therapy.

MEK inhibitor cobimetinib rescues a dRaf mutant lethal phenotype in Drosophila melanogaster.

Since Drosophila melanogaster has proven to be a useful model system to study phenotypes of oncogenic mutations and to identify new anti-cancer drugs, we generated human BRAFV600E homologous dRaf mutant (dRafA572E ) Drosophila melanogaster strains to use these for characterisation of mutant phenotypes and exploit these phenotypes for drug testing. For mutant gene expression, the GAL4/UAS expression system was used. dRafA572E was expressed tissue-specific in the eye, epidermis, heart, wings, secretory glands and in the whole animal. Expression of dRaf A572E under the control of an eye-specific driver led to semi-lethality and a rough eye phenotype. The vast majority of other tissue-specific and ubiquitous drivers led to a lethal phenotype only. The rough eye phenotype was used to test BRAF inhibitor vemurafenib and MEK1/2 inhibitor cobimetinib. There was no phenotype rescue by this treatment. However, a significant rescue of the lethal phenotype was observed under a gut-specific driver. Here, MEK1/2 inhibitor cobimetinib rescued Drosophila larvae to reach pupal stage in 37% of cases as compared to 1% in control experiments. Taken together, the BRAFV600E homolog dRaf A572E exerts mostly lethal effects in Drosophila. Gut-specific dRaf A572E expression might in future be developed further for drug testing.

Perturbation of mitochondrial bioenergetics by polycations counteracts resistance to BRAFE600 inhibition in melanoma cells.

Acquired resistance to the oncogenic BRAFE600 inhibitor vemurafenib is a major clinical challenge in the treatment of melanoma. Vemurafenib resistance is poorly understood; however, available evidence indicates that reprogrammed mitochondrial metabolism could contribute to the resistance mechanism. Here we show that synthetic polycations, such as polyethylenimines and poly(l-lysine)s, prevent vemurafenib resistance in melanoma cells through induction of mitochondrial bioenergetic crisis. Polycations accumulate to a higher degree in hyperpolarized mitochondria (i.e. mitochondria with greater negative charge) which partly explains greater cellular uptake and mitochondrial accumulation of polycations in melanoma cells compared with epidermal melanocytes. Combined treatment of polycations and vemurafenib diminishes the metabolic flexibility of melanoma cells, making them unable to shift between glycolysis and mitochondrial oxidative phosphorylation according to energy demands. Thus, polycations exert considerable detrimental effects on melanoma cells at concentrations better tolerated by epidermal melanocytes and act synergistically with vemurafenib in effectuating bioenergetic crisis, DNA damage and cell death selectively in melanoma cells. Mechanistic understanding of this synergy could lead to the development of macromolecular and polymer therapeutics with structural attributes that encompass even greater cancer-specific cytotoxicity, and provide strategies for tailor-made combination therapies.

What's New in Melanoma.

Melanoma is rapidly evolving because of advances in noninvasive diagnosis, targeted therapies, and improved prognostic methods. This article discusses what is new in melanoma risk factors, prevention, clinical management, and targeted treatment. The incidence continues to increase worldwide, whereas mortality is steadily improving. This trend reinforces the importance of dermatologists comprehensively understanding all aspects of melanoma. Further research is needed to continue making a material impact on outcomes for patients.

Bixin, an apocarotenoid isolated from Bixa orellana L., sensitizes human melanoma cells to dacarbazine-induced apoptosis through ROS-mediated cytotoxicity.

Cutaneous melanoma has a high capacity to metastasize and significant resistance to conventional therapeutic protocols, which makes its treatment difficult. The combination of conventional drugs with cytostatic molecules of low toxicity has been shown to be an interesting alternative for sensitization of tumor cells to chemotherapy. In this study, we evaluated the effect of bixin, an abundant apocarotenoid present in Bixa orellana, on the sensitization of human melanoma cells (A2058) to dacarbazine treatment, an anticancer agent clinically used for the therapy of metastatic melanoma. UPLC-DAD-MS/MS analyses of bioactive extracts from B. orellana seeds led to the identification of two new apocarotenoids: 6,8'-diapocarotene-6,8'-dioic acid and 6,7'-diapocarotene-6,7'-dioic acid. After being identified as its major compound, bixin (Z-bixin) was evaluated on A2058 cells expressing the oncogenic BRAF VE600 mutation and resistant to dacarbazine treatment. Bixin promoted growth inhibition, reduced cell migration, induced apoptosis and cell cycle arrest in the G2/M phase. When associated with dacarbazine, bixin restored the sensitivity of A2058 cells to chemotherapy, enhancing its antiproliferative, anti-migratory and pro-apoptotic effects. Combined treatment also induced higher ROS (reactive oxygen species) and MDA (malondialdehyde, a lipid peroxidation marker) generation than monotreatment, suggesting that the oxidative stress caused by bixin contributes significantly to its sensitizing effect. Taken together, these data suggest that bixin exerts intrinsic antimelanoma activity by mechanisms complementary to those of dacarbazine, encouraging its use in combined therapy for cutaneous melanoma treatment.

A phenotypic Caenorhabditis elegans screen identifies a selective suppressor of antipsychotic-induced hyperphagia.

Antipsychotic (AP) drugs are used to treat psychiatric disorders but are associated with significant weight gain and metabolic disease. Increased food intake (hyperphagia) appears to be a driving force by which APs induce weight gain but the mechanisms are poorly understood. Here we report that administration of APs to C. elegans induces hyperphagia by a mechanism that is genetically distinct from basal food intake. We exploit this finding to screen for adjuvant drugs that suppress AP-induced hyperphagia in C. elegans and mice. In mice AP-induced hyperphagia is associated with a unique hypothalamic gene expression signature that is abrogated by adjuvant drug treatment. Genetic analysis of this signature using C. elegans identifies two transcription factors, nhr-25/Nr5a2 and nfyb-1/NFYB to be required for AP-induced hyperphagia. Our study reveals that AP-induced hyperphagia can be selectively suppressed without affecting basal food intake allowing for novel drug discovery strategies to combat AP-induced metabolic side effects.

Copper Chelation as Targeted Therapy in a Mouse Model of Oncogenic BRAF-Driven Papillary Thyroid Cancer.

Purpose: Sixty percent of papillary thyroid cancers (PTC) have an oncogenic (V600E) BRAF mutation. Inhibitors of BRAF and its substrates MEK1/2 are showing clinical promise in BRAFV600E PTC. PTC progression can be decades long, which is challenging in terms of toxicity and cost. We previously found that MEK1/2 require copper (Cu) for kinase activity and can be inhibited with the well-tolerated and economical Cu chelator tetrathiomolybdate (TM). We therefore tested TM for antineoplastic activity in BRAFV600E -positive PTC.Experimental Design: The efficacy of TM alone and in combination with current standard-of-care lenvatinib and sorafenib or BRAF and MEK1/2 inhibitors vemurafenib and trametinib was examined in BRAFV600E-positive human PTC cell lines and a genetically engineered mouse PTC model.Results: TM inhibited MEK1/2 kinase activity and transformed growth of PTC cells. TM was as or more potent than lenvatinib and sorafenib and enhanced the antineoplastic activity of sorafenib and vemurafenib. Activated ERK2, a substrate of MEK1/2, overcame this effect, consistent with TM deriving its antineoplastic activity by inhibiting MEK1/2. Oral TM reduced tumor burden and vemurafenib in a BrafV600E -positive mouse model of PTC. This effect was ascribed to a reduction of Cu in the tumors. TM reduced P-Erk1/2 in mouse PTC tumors, whereas genetic reduction of Cu in developing tumors trended towards a survival advantage. Finally, TM as a maintenance therapy after cessation of vemurafenib reduced tumor volume in the aforementioned PTC mouse model.Conclusions: TM inhibits BRAFV600E -driven PTC through inhibition of MEK1/2, supporting clinical evaluation of chronic TM therapy for this disease. Clin Cancer Res; 24(17); 4271-81. ©2018 AACR.

Pericytes Elicit Resistance to Vemurafenib and Sorafenib Therapy in Thyroid Carcinoma via the TSP-1/TGFß1 Axis.

PURPOSE: The BRAFV600E oncogene modulates the papillary thyroid carcinoma (PTC) microenvironment, in which pericytes are critical regulators of tyrosine-kinase (TK)-dependent signaling pathways. Although BRAFV600E and TK inhibitors are available, their efficacy as bimodal therapeutic agents in BRAFV600E-PTC is still unknown. EXPERIMENTAL DESIGN: We assessed the effects of vemurafenib (BRAFV600E inhibitor) and sorafenib (TKI) as single agents or in combination in BRAFWT/V600E-PTC and BRAFWT/WT cells using cell-autonomous, pericyte coculture, and an orthotopic mouse model. We also used BRAFWT/V600E-PTC and BRAFWT/WT-PTC clinical samples to identify differentially expressed genes fundamental to tumor microenvironment. RESULTS: Combined therapy blocks tumor cell proliferation, increases cell death, and decreases motility via BRAFV600E inhibition in thyroid tumor cells in vitro. Vemurafenib produces cytostatic effects in orthotopic tumors, whereas combined therapy (likely reflecting sorafenib activity) generates biological fluctuations with tumor inhibition alternating with tumor growth. We demonstrate that pericytes secrete TSP-1 and TGFß1, and induce the rebound of pERK1/2, pAKT and pSMAD3 levels to overcome the inhibitory effects of the targeted therapy in PTC cells. This leads to increased BRAFV600E-PTC cell survival and cell death refractoriness. We find that BRAFWT/V600E-PTC clinical samples are enriched in pericytes, and TSP1 and TGFß1 expression evoke gene-regulatory networks and pathways (TGFß signaling, metastasis, tumor growth, tumor microenvironment/ECM remodeling functions, inflammation, VEGF ligand-VEGF receptor interactions, immune modulation, etc.) in the microenvironment essential for BRAFWT/V600E-PTC cell survival. Critically, antagonism of the TSP-1/TGFß1 axis reduces tumor cell growth and overcomes drug resistance. CONCLUSIONS: Pericytes shield BRAFV600E-PTC cells from targeted therapy via TSP-1 and TGFß1, suggesting this axis as a new therapeutic target for overcoming resistance to BRAFV600E and TK inhibitors.

BRAF inhibition with concomitant tumor treating fields for a multiply progressive pleomorphic xanthoastrocytoma.

Pleomorphic xanthoastrocytomas can be very resistant to treatment if they progress after standard therapy with surgery and radiation. We present the case of a patient with a multiply recurrent pleomorphic xanthoastrocytoma which demonstrated a sustained partial response to a combination regimen of the BRAF inhibitor vemurafenib and tumor treating fields. The regimen proved tolerable and efficacious in this case.

Dual direction CRISPR transcriptional regulation screening uncovers gene networks driving drug resistance.

Pooled CRISPR-Cas9 knock out screens provide a valuable addition to the methods available for novel drug target identification and validation. However, where gene editing is targeted to amplified loci, the resulting multiple DNA cleavage events can be a cause of false positive hit identification. The generation of nuclease deficient versions of Cas9 has enabled the development of two additional techniques - CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) - that enable the repression or overexpression, respectively, of target genes. Here we report the first direct combination of all three approaches (CRISPRko, CRISPRi and CRISPRa) in the context of genome-wide screens to identify components that influence resistance and sensitivity to the BRAF inhibitor, vemurafenib. The pairing of both loss- and gain-of-function datasets reveals complex gene networks which control drug response and illustrates how such data can add substantial confidence to target identification and validation analyses.