RESUMEN
Despite significant advances in targeted therapies against the hyperactivated BRAFV600/MEK pathway for patients with unresectable metastatic melanoma, acquired resistance remains an unsolved clinical problem. In this study, we focused on melanoma cells resistant to trametinib, an agent broadly used in combination therapies. Molecular and cellular changes were assessed during alternating periods of trametinib withdrawal and rechallenge in trametinib-resistant cell lines displaying either a differentiation phenotype (MITFhigh/NGFRlow) or neural crest stem-like dedifferentiation phenotype (NGFRhigh/MITFlow). Neither drug withdrawal nor drug rechallenge induced cell death, and instead of loss of fitness, trametinib-resistant melanoma cells adapted to altered conditions by phenotype switching. In resistant cells displaying a differentiation phenotype, trametinib withdrawal markedly decreased MITF level and activity, which was associated with reduced cell proliferation capacity, and induced stemness assessed as NGFR-positive cells and senescence features, including IL-8 expression and secretion. All these changes could be reversed by trametinib re-exposure, which emphasizes melanoma cell plasticity. Trametinib-resistant cells displaying a dedifferentiation phenotype were less responsive presumably due to the already low level of MITF, a master regulator of the melanoma phenotype. Considering new directions of the development of anti-melanoma treatment, our study suggests that the phenotype of melanomas resistant to targeted therapy might be a crucial determinant of the selection of second-line therapy for melanoma patients.
Asunto(s)
Interleucina-8 , Melanoma , Humanos , Interleucina-8/genética , Melanoma/tratamiento farmacológico , Melanoma/genética , Melanoma/patología , Piridonas/farmacología , Piridonas/uso terapéutico , Pirimidinonas/uso terapéutico , Fenotipo , Proteínas Proto-Oncogénicas B-raf/genética , Factor de Transcripción Asociado a Microftalmía/genética , Factor de Transcripción Asociado a Microftalmía/metabolismo , Proteínas del Tejido Nervioso/genética , Receptores de Factor de Crecimiento Nervioso/genéticaRESUMEN
HSP90 (heat shock protein 90) is an ATP-dependent molecular chaperone involved in a proper folding and maturation of hundreds of proteins. HSP90 is abundantly expressed in cancer, including melanoma. HSP90 client proteins are the key oncoproteins of several signaling pathways controlling melanoma development, progression and response to therapy. A number of natural and synthetic compounds of different chemical structures and binding sites within HSP90 have been identified as selective HSP90 inhibitors. The majority of HSP90-targeting agents affect N-terminal ATPase activity of HSP90. In contrast to N-terminal inhibitors, agents interacting with the middle and C-terminal domains of HSP90 do not induce HSP70-dependent cytoprotective response. Several inhibitors of HSP90 were tested against melanoma in pre-clinical studies and clinical trials, providing evidence that these agents can be considered either as single or complementary therapeutic strategy. This review summarizes current knowledge on the role of HSP90 protein in cancer with focus on melanoma, and provides an overview of structurally different HSP90 inhibitors that are considered as potential therapeutics for melanoma treatment.
Asunto(s)
Antineoplásicos/administración & dosificación , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Melanoma/metabolismo , Animales , Antineoplásicos/química , Proteínas del Choque Térmico HSP72/genética , Proteínas del Choque Térmico HSP72/metabolismo , Proteínas HSP90 de Choque Térmico/química , Proteínas HSP90 de Choque Térmico/genética , Proteínas HSP90 de Choque Térmico/metabolismo , Humanos , Melanoma/tratamiento farmacológico , Melanoma/genética , Dominios ProteicosRESUMEN
Resisting cell death is a hallmark of cancer. Disturbances in the execution of cell death programs promote carcinogenesis and survival of cancer cells under unfavorable conditions, including exposition to anti-cancer therapies. Specific modalities of regulated cell death (RCD) have been classified based on different criteria, including morphological features, biochemical alterations and immunological consequences. Although melanoma cells are broadly equipped with the anti-apoptotic machinery and recurrent genetic alterations in the components of the RAS/RAF/MEK/ERK signaling markedly contribute to the pro-survival phenotype of melanoma, the roles of autophagy-dependent cell death, necroptosis, ferroptosis, pyroptosis, and parthanatos have recently gained great interest. These signaling cascades are involved in melanoma cell response and resistance to the therapeutics used in the clinic, including inhibitors of BRAFmut and MEK1/2, and immunotherapy. In addition, the relationships between sensitivity to non-apoptotic cell death routes and specific cell phenotypes have been demonstrated, suggesting that plasticity of melanoma cells can be exploited to modulate response of these cells to different cell death stimuli. In this review, the current knowledge on the non-apoptotic cell death signaling pathways in melanoma cell biology and response to anti-cancer drugs has been discussed.
Asunto(s)
Susceptibilidad a Enfermedades , Melanoma/etiología , Melanoma/metabolismo , Transducción de Señal , Animales , Muerte Celular Autofágica , Biomarcadores de Tumor , Muerte Celular , Ferroptosis/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Melanoma/diagnóstico , Melanoma/terapia , Necroptosis/genética , Piroptosis , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Melanoma remains incurable skin cancer, and targeting heat shock protein 90 (HSP90) is a promising therapeutic approach. In this study, we investigate the effect of 17-aminogeldanamycin, a potent HSP90 inhibitor, on nuclear factor-kappa B (NF-κB) activity in BRAFV600E and NRASQ61R patient-derived melanoma cell lines. We performed time-lapse microscopy and flow cytometry to monitor changes in cell confluence and viability. The NF-κB activity was determined by immunodetection of phospho-p65 and assessment of expression of NF-κB-dependent genes by quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA). Constitutive activity of p65/NF-κB was evident in all melanoma cell lines. Differences in its level might be associated with genetic alterations in CHUK, IL1B, MAP3K14, NFKBIE, RIPK1, and TLR4, while differences in transcript levels of NF-κB-inducible genes revealed by PCR array might result from the contribution of other regulatory mechanisms. 17-Aminogeldanamycin markedly diminished the level of phospho-p65, but the total p65 protein level was unaltered, indicating that 17-aminogeldanamycin inhibited activation of p65/NF-κB. This conclusion was supported by significantly reduced expression of selected NF-κB-dependent genes: cyclin D1 (CCND1), C-X-C motif chemokine ligand 8 (CXCL8), and vascular endothelial growth factor (VEGF), as shown at transcript and protein levels, as well as secretion of IL-8 and VEGF. Our study indicates that 17-aminogeldanamycin can be used for efficient inhibition of NF-κB activity and the simultaneous diminution of IL-8 and VEGF levels in the extracellular milieu of melanoma.
Asunto(s)
Benzoquinonas/farmacología , Lactamas Macrocíclicas/farmacología , Melanoma/metabolismo , FN-kappa B/metabolismo , Línea Celular Tumoral , Ciclina D1/genética , Ciclina D1/metabolismo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Interleucina-8/genética , Interleucina-8/metabolismo , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/metabolismo , Células Tumorales Cultivadas , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Outcomes of melanoma patient treatment remain unsatisfactory despite accessibility of oncoprotein-targeting drugs and immunotherapy. Here, we reported that 17-aminogeldanamycin more potently activated caspase-3/7 in BRAFV600E melanoma cells than geldanamycin, another inhibitor of heat shock protein 90 (HSP90). 17-aminogeldanamycin alleviated self-triggered compensatory increase in HSP70 mRNA level and induced endoplasmic reticulum (ER) stress, which was followed by selective diminution of cytoprotective IRE1α-XBP1s pathway activity of unfolded protein response (UPR), inhibition of ERK1/2 activity and induction of apoptosis. Concomitantly, ATF6/p50 level and expression of PERK-dependent genes, CHOP and BIM, remained unaltered. This might result from an inframe deletion in EIF2AK3 leading to a PERKL21del variant revealed by whole-exome sequencing in melanoma cell lines. 17-aminogeldanamycin exhibited similar activity in NRASQ61R melanoma cells that harbored a heterozygous inactivating variant of NAD(P)H:quinone oxidoreductase 1 (NQO1P187S). In addition, 17-aminogeldanamycin acted cooperatively with trametinib (an inhibitor of MEK1/2) and vemurafenib (an inhibitor of BRAFV600E) in induction of apoptosis in melanoma cell lines as evidenced by in-cell caspase-3/7 activation and PARP cleavage that occurred earlier compared with either drug used alone. As trametinib and vemurafenib did not significantly affect HSP70 and GRP78 transcript levels, cooperation of MEK/BRAFV600E inhibitors and 17-aminogeldanamycin might result from a concurrent inhibition of the RAS/RAF/MEK/ERK cascade and IRE1α-dependent signaling, and cell-intrinsic ER homeostasis can determine the extent of the drug cooperation. Our study indicates that 17-aminogeldanamycin takes several advantages compared with other HSP90-targeting compounds, and can complement activity of BRAF/MEK inhibitors in melanoma cells of different genetic subtypes.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Benzoquinonas/farmacología , Endorribonucleasas/metabolismo , Lactamas Macrocíclicas/farmacología , Melanoma/genética , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal/efectos de los fármacos , Benzoquinonas/química , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Chaperón BiP del Retículo Endoplásmico , Estrés del Retículo Endoplásmico/efectos de los fármacos , GTP Fosfohidrolasas/genética , Proteínas de Choque Térmico/genética , Humanos , Lactamas Macrocíclicas/química , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 2/antagonistas & inhibidores , Melanoma/metabolismo , Melanoma/patología , Proteínas de la Membrana/genética , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/genética , Respuesta de Proteína Desplegada/efectos de los fármacos , Proteína 1 de Unión a la X-Box/metabolismoRESUMEN
We have extensively studied the phenotypic heterogeneity of patient-derived melanoma cells. Here, whole-exome sequencing revealed novel variants of genes associated with the MAPK, NOTCH, Hippo, cell-cycle, senescence, and ubiquitin-dependent pathways, which could contribute to the observed phenotypic diversity between cell lines. Focusing on mutations in the MAPK pathway-associated genes, we found BRAF (BRAFV600E ) and RAS subtypes, including NRASQ61R and the rare HRASQ61R variant, and additional alterations potentially leading to different ERK1/2 activity. Both RASQ61R cell lines harbored a MEK1P124S variant and exerted a low level of phospho-MEK1/2. Activity of the MAPK pathway was further attenuated in NRASQ61R /MEKP124S cells by trametinib, and this effect was also shown in HRASQ61R /MEKP124S melanoma cells. The observed variability in doubling time might be a consequence of diverse MAPK and PI3K/AKT pathway activities, but not exclusively, as a senescence program was also executed to different extent in distinct melanoma cell lines. Low percentages of senescent cells might result from mutations in CDKN2A, E2F3, and EZH2, and a high c-MYC expression. Vemurafenib and trametinib induced senescence concomitantly with c-MYC downregulation and irrespectively of CDKN2A mutation, but the EZH2S412C variant might limit senescence induction. Damaging alterations in Hippo pathway-associated genes were accompanied with variability in the phosphorylation level of YAP1/TAZ and CTGF expression. Our study also suggests opposite activity of NOTCH2F1209V and NOTCH2N2002S variants. Additionally, we found a novel FBXW7V418M variant that retained its function in melanoma cells. The obtained molecular data might be further exploited in genotype-phenotype relationship studies and in identifying novel biomarkers and therapies for melanomas.
Asunto(s)
Biomarcadores de Tumor/genética , Senescencia Celular , Secuenciación del Exoma/métodos , Melanoma/genética , Mutación , Inhibidores de Proteínas Quinasas/farmacología , Apoptosis , Ciclo Celular , Proliferación Celular , Humanos , Melanoma/tratamiento farmacológico , Melanoma/patología , Fenotipo , Fosforilación , Células Tumorales CultivadasRESUMEN
Cancer cell phenotype largely depends on oxygen availability. The atmospheric oxygen concentration (21%) used in in vitro studies is much higher than in any human tissue. Using well-characterized patient-derived melanoma cell lines, we compared: (i) activities of several signaling pathways, and (ii) the effects of vemurafenib and trametinib in hyperoxia (21% O2), normoxia (6% O2) and hypoxia (1% O2). A high plasticity of melanoma cells in response to changes in oxygen supplementation and drug treatment was observed, and the transcriptional reprograming and phenotypic changes varied between cell lines. Normoxia enhanced the expression of vascular endothelial growth factor (VEGF), glucose metabolism/transport-related genes, and changed percentages of NGFR- and MITF-positive cells in cell line-dependent manner. Increased protein stability might be responsible for high PGC1α level in MITFlow melanoma cells. Vemurafenib and trametinib while targeting the activity of MAPK/ERK pathway irrespective of oxygen concentration, were less effective in normoxia than hyperoxia in reducing levels of VEGF, PGC1α, SLC7A11 and Ki-67-positive cells in cell line-dependent manner. In conclusion, in vitro studies performed in atmospheric oxygen concentration provide different information on melanoma cell phenotype and response to drugs than performed in normoxia, which might partially explain the discrepancies between results obtained in vitro and in clinical settings.
Asunto(s)
Resistencia a Antineoplásicos , Melanoma/metabolismo , Oxígeno/metabolismo , Hipoxia Tumoral , Antineoplásicos/farmacología , Línea Celular Tumoral , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Factor de Transcripción Asociado a Microftalmía/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Fenotipo , Inhibidores de Proteínas Quinasas/farmacología , Piridonas/farmacología , Pirimidinonas/farmacología , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismo , Vemurafenib/farmacologíaRESUMEN
Clinical evidence has revealed that while RAS/RAF/MEK/ERK pathway is a crucial component of melanomagenesis, other signaling pathways can also contribute to the malignant growth and development of resistance to targeted therapies. We explored the response of V600EBRAF melanoma cells derived from surgical specimens and grown in stem cell medium to vemurafenib and trametinib, drugs targeting the activity of V600EBRAF and MEK1/2, respectively. Cell growth and apoptosis were monitored by real-time imaging system, immunophenotype and cell cycle by flow cytometry, gene expression by quantitative real-time PCR, immunoblotting and enzyme-linked immunosorbent assay. The V600EBRAF melanoma cell populations were diverse. Differences in morphology, pigmentation, cell cycle profiles, and immunophenotype were observed. At the molecular level, melanoma cells differed in the phosphorylation of ERK1/2, NF-κB, and ß-catenin, and expression of several relevant genes, including MITF-M, DKK1, CCND1, BRAF, CXCL8, and CTGF. Despite having different characteristics, melanoma cells responded similarly to vemurafenib and trametinib. Both drugs reduced ERK1/2 phosphorylation and percentages of cells expressing Ki-67 at high level, inhibited expression of CCND1 and induced cell cycle arrest in the Go/G1 phase. These expected cytostatic effects were accompanied by increased CD271 expression, a marker of stem-like cells. NF-κB activity was reduced by both drugs, however, not completely abolished, whereas the level of active ß-catenin was increased by drugs in three out of six cell populations. Interestingly, expression of IL-8 and CTGF was significantly reduced by treatment with vemurafenib and trametinib. Simultaneous inhibition of NF-κB activity and induction of ERK1/2 phosphorylation revealed that CTGF expression depends on ERK1/2 activity but not on NF-κB activity. Both, the positive effects of treatment with vemurafenib and trametinib such as the newly identified CTGF suppression and undesired effects such as increased CD271 expression suggesting selection of melanoma stem-like cells should be considered in the development of combination treatment for melanoma patients.
Asunto(s)
Antineoplásicos/farmacología , Factor de Crecimiento del Tejido Conjuntivo/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Interleucina-8/genética , Mutación , Proteínas Proto-Oncogénicas B-raf/genética , Apoptosis/efectos de los fármacos , Apoptosis/genética , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Factor de Crecimiento del Tejido Conjuntivo/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Citometría de Flujo , Humanos , Immunoblotting , Indoles/farmacología , Interleucina-8/metabolismo , Melanoma/genética , Melanoma/metabolismo , Melanoma/patología , FN-kappa B/metabolismo , Fosforilación/efectos de los fármacos , Piridonas/farmacología , Pirimidinonas/farmacología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sulfonamidas/farmacología , Células Tumorales Cultivadas , Vemurafenib , beta Catenina/metabolismoRESUMEN
MITF (microphthalmia-associated transcription factor) represents a melanocytic lineage-specific transcription factor whose role is profoundly extended in malignant melanoma. Over the last few years, the function of MITF has been tightly connected to plasticity of melanoma cells. MITF participates in executing diverse melanoma phenotypes defined by distinct gene expression profiles. Mutation-dependent alterations in MITF expression and activity have been found in a relatively small subset of melanomas. MITF activity is rather modulated by its upstream activators and suppressors operating on transcriptional, post-transcriptional and post-translational levels. These regulatory mechanisms also include epigenetic and microenvironmental signals. Several transcription factors and signaling pathways involved in the regulation of MITF expression and/or activity such as the Wnt/ß-catenin pathway are broadly utilized by various types of tumors, whereas others, e.g., BRAF(V600E)/ERK1/2 are more specific for melanoma. Furthermore, the MITF activity can be affected by the availability of transcriptional co-partners that are often redirected by MITF from their own canonical signaling pathways. In this review, we discuss the complexity of a multilevel regulation of MITF expression and activity that underlies distinct context-related phenotypes of melanoma and might explain diverse responses of melanoma patients to currently used therapeutics.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , Melanoma/genética , Factor de Transcripción Asociado a Microftalmía/genética , Transducción de Señal/genética , Humanos , Melanoma/metabolismo , Melanoma/patología , Factor de Transcripción Asociado a Microftalmía/metabolismo , Modelos Genéticos , Biosíntesis de Proteínas , Transcripción Genética , Microambiente Tumoral/genéticaRESUMEN
BRAF is mutated at a high frequency in various malignancies, including melanoma, papillary thyroid carcinoma and colorectal adenocarcinoma. BRAF is an element of the RAS/RAF/MEK/ERK (MAPK) pathway, which when constitutively active can lead to increased proliferation rate, enhanced survival, invasion and metastasis. The development of small molecule inhibitors of mutant BRAF kinase has changed the care of patients, especially with melanoma. Despite the success in treating melanoma with inhibitors of mutant BRAF and other elements of RAS/RAF/MEK/ERK (MAPK) pathway, resistance limits the long-term responsiveness to these drugs. The resistance mechanisms to MAPK pathway inhibition are complex, occur at genomic and phenotypic levels, and frequently the same patient can simultaneously develop diverse mechanisms of resistance in different progressive metastases or even in the same lesion. In the current review, we summarize recent research on mutations in BRAF and their importance for the development of tumor. This review will also give an overview on the current knowledge concerning therapies for patients harboring mutation in BRAF and discusses the diverse mechanisms of resistance developed in response to these targeted therapies.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Carcinoma/tratamiento farmacológico , Neoplasias Colorrectales/tratamiento farmacológico , Melanoma/tratamiento farmacológico , Proteínas Proto-Oncogénicas B-raf/genética , Neoplasias de la Tiroides/tratamiento farmacológico , Adenocarcinoma/genética , Carcinoma/genética , Carcinoma Papilar , Neoplasias Colorrectales/genética , Progresión de la Enfermedad , Humanos , Melanoma/genética , Mutación , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Cáncer Papilar Tiroideo , Neoplasias de la Tiroides/genéticaRESUMEN
Melanomas are highly heterogeneous tumors and there is no treatment effective at achieving long-term remission for metastatic melanoma patients. Thus, an appropriate model system for studying melanoma biology and response to drugs is necessary. It has been shown that composition of the medium is a critical factor in preserving the complexity of the tumor in in vitro settings, and melanospheres maintained in stem cell medium are a good model in this respect. In the present study, we observed that not all nodular melanoma patient-derived cell populations grown in stem cell medium were capable of forming melanospheres, and cell aggregates and anchorage-independent single-cell cultures emerged instead. Self-renewing capacity and unlimited growth potential indicated the presence of cells with stem-like properties in all patient-derived populations but immunophenotype and MITF expression exhibited variability. Enhanced MITF expression and activity was observed in melanospheres in comparison with cell aggregates and single-cell culture, and hypoxic-like conditions that increased the ability of single-cell population to form melanospheres enhanced MITF expression and cell pigmentation as well. Thus, MITF seems to be a critical transcription factor for formation of both patient-derived and hypoxia-induced melanospheres. After 2 years of continuous culturing, melanospheres progressively underwent transition into cell aggregates that was accompanied by changes in expression of several MITF-dependent genes associated with melanogenesis and survival and alterations in the composition of subpopulations but not in the frequency of ABCB5-positive cells. Several biological properties of parent tumor are well preserved in patient-derived melanospheres, but during prolonged culturing the heterogeneity is substantially lost when the melanospheres are substituted by cell aggregates. This should be considered when cell aggregates instead of melanospheres are used in the study of melanoma biology and cell response to drugs.
Asunto(s)
Melanoma/química , Melanoma/metabolismo , Células Madre Neoplásicas/citología , Esferoides Celulares/citología , Antígeno AC133 , Antígenos CD/química , Antígenos CD/metabolismo , Técnicas de Cultivo de Célula , Hipoxia de la Célula , Medios de Cultivo , Glicoproteínas/química , Glicoproteínas/metabolismo , Humanos , Factor de Transcripción Asociado a Microftalmía/química , Factor de Transcripción Asociado a Microftalmía/metabolismo , Monofenol Monooxigenasa/química , Monofenol Monooxigenasa/metabolismo , Células Madre Neoplásicas/química , Células Madre Neoplásicas/metabolismo , Péptidos/química , Péptidos/metabolismo , Esferoides Celulares/química , Esferoides Celulares/metabolismo , Células Tumorales CultivadasRESUMEN
Dacarbazine induces a clinical response only in 15% of melanoma patients. New treatment strategies may involve combinations of drugs with different modes of action to target the tumor heterogeneity. We aimed to determine whether the combined treatment of heterogeneous melanoma cell populations in vitro with the alkylating agent dacarbazine and the nuclear factor-κB inhibitor parthenolide could be more effective than either drug alone. A panel of melanoma cell lines, including highly heterogeneous populations derived from surgical specimens, was treated with dacarbazine and parthenolide. The effect of drugs on the viable cell number was examined using an acid phosphatase activity assay, and the combination effect was determined by median-effect analysis. Cell death and cell-cycle arrest were assessed by flow cytometry. Gene expression was measured by real-time PCR and changes in the protein levels were evaluated by western blotting. Secretion of vascular endothelial growth factor and interleukin-8 was determined using an enzyme-linked immunosorbent assay. The self-renewing capacity was assessed using a clonogenic assay. Dacarbazine was less effective in heterogeneous melanoma populations than in the A375 cell line. Parthenolide and dacarbazine synergistically reduced the viable cell numbers. Both drugs induced cell-cycle arrest and apoptotic cell death. Importantly, parthenolide abrogated the baseline and dacarbazine-induced vascular endothelial growth factor secretion from melanoma cells in heterogeneous populations, whereas interleukin-8 secretion was not significantly affected by either drug. Parthenolide eradicated melanoma cells with self-renewing capacity also in cultures simultaneously treated with dacarbazine. The combination of parthenolide and dacarbazine might be considered as a new therapeutic modality against metastatic melanoma.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Melanoma/patología , Neoplasias Cutáneas/patología , Antineoplásicos Alquilantes/farmacología , Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Western Blotting , Puntos de Control del Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Dacarbazina/farmacología , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Humanos , Interleucina-8/metabolismo , Melanoma/genética , Melanoma/metabolismo , FN-kappa B/antagonistas & inhibidores , FN-kappa B/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sesquiterpenos/farmacología , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Proteins from the BCL-2 family control cell survival and apoptosis in health and disease, and regulate apoptosis-unrelated cellular processes. BCL-Gonad (BCL-G, also known as BCL2-like 14) is a non-typical protein of the family as its long isoform (BCL-GL) consists of BH2 and BH3 domains without the BH1 motif. BCL-G is predominantly expressed in normal testes and different organs of the gastrointestinal tract. The complexity of regulatory mechanisms of BCL-G expression and post-translational modifications suggests that BCL-G may play distinct roles in different types of cells and disorders. While several genetic alterations of BCL2L14 have been reported, gene deletions and amplifications prevail, which is also confirmed by the analysis of sequencing data for different types of cancer. Although the studies validating the phenotypic consequences of genetic manipulations of BCL-G are limited, the role of BCL-G in apoptosis has been undermined. Recent studies using gene-perturbation approaches have revealed apoptosis-unrelated functions of BCL-G in intracellular trafficking, immunomodulation, and regulation of the mucin scaffolding network. These studies were, however, limited mainly to the role of BCL-G in the gastrointestinal tract. Therefore, further efforts using state-of-the-art methods and various types of cells are required to find out more about BCL-G activities. Deciphering the isoform-specific functions of BCL-G and the BCL-G interactome may result in the designing of novel therapeutic approaches, in which BCL-G activity will be either imitated using small-molecule BH3 mimetics or inhibited to counteract BCL-G upregulation. This review summarizes two decades of research on BCL-G.
Asunto(s)
Proteínas Proto-Oncogénicas c-bcl-2 , Proteínas Proto-Oncogénicas , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteína X Asociada a bcl-2RESUMEN
BACKGROUND: Although BRAFV600/MEK inhibitors improved the treatment of melanoma patients, resistance is acquired almost inevitably. METHODS: Trametinib withdrawal/rechallenge and MCL-1 inhibition in trametinib-resistance models displaying distinct p-ERK1/2 levels were investigated. RESULTS: Trametinib withdrawal/rechallenge caused reversible changes in ERK1/2 activity impacting the balance between pro-survival and pro-apoptotic proteins. Reversible alterations were found in MCL-1 levels and MCL-1 inhibitors, BIM and NOXA. Taking advantage of melanoma cell dependency on MCL-1 for survival, we used S63845. While it was designed to inhibit MCL-1 activity, we showed that it also significantly reduced NOXA levels. S63845-induced apoptosis was detected as the enhancement of Annexin V-positivity, caspase-3/7 activation and histone H2AX phosphorylation. Percentages of Annexin V-positive cells were increased most efficiently in trametinib-resistant melanoma cells displaying the p-ERK1/2low/MCL-1low/BIMhigh/NOXAlow phenotype with EC50 values at concentrations as low as 0.1 µM. Higher ERK1/2 activity associated with increased MCL-1 level and reduced BIM level limited pro-apoptotic activity of S63845 further influenced by a NOXA level. CONCLUSIONS: Our study supports the notion that the efficiency of an agent designed to target a single protein can largely depend on the phenotype of cancer cells. Thus, it is important to define appropriate phenotype determinants to stratify the patients for the novel therapy.
RESUMEN
The basis for targeting specific components of the apoptotic machinery for anticancer therapy is the detailed knowledge on molecular mechanisms that regulate this complex cell death pathway. As the mitochondrial pathway of apoptosis is the major route to respond to stress stimuli including anticancer drugs, and that pathway is largely impaired in cancer cells, leading to tumor formation and treatment resistance, a variety of approaches have been developed to restore the function of the mitochondrial pathway in cancer cells. BH3-only proteins, being important inducers of the mitochondrial pathway, either directly stimulate proapoptotic Bax-like proteins or interfere with antiapoptotic Bcl-2 proteins. Therefore, the development of molecules able to mimic the function of BH3-only proteins is considered a promising strategy to improve cancer cell response to treatment. Several BH3 mimetics have been designed and studied in various tumors, in both in vitro and in vivo settings. Some of them are currently being evaluated in clinical trials either alone or in combination with conventional anticancer drugs. BH3 profiling of cancer cells was introduced to better predict the responsiveness of tumor cells to BH3 mimetics combined with conventional therapies. In this review, we summarize the current knowledge on BH3-only proteins and describe the spectrum of strategies employing BH3 mimetics in preclinical and clinical studies that aim at tumor targeting.
Asunto(s)
Antineoplásicos/uso terapéutico , Proteínas Reguladoras de la Apoptosis/uso terapéutico , Biomimética/métodos , Terapia Molecular Dirigida , Neoplasias/tratamiento farmacológico , Fragmentos de Péptidos/uso terapéutico , Proteínas Proto-Oncogénicas/uso terapéutico , Apoptosis/efectos de los fármacos , Humanos , Mitocondrias/metabolismoRESUMEN
The clinical course of patients with chronic lymphocytic leukemia (CLL) is highly heterogeneous. Gene expression analyses have revealed that leukemic cells with unmutated immunoglobulin heavy chain genes (IgV H ) differ from CLL cells with mutated IgV H in the expression level of some genes, i.e. encoding kinase ZAP-70 and antigen CD38. Recently, additional markers in CLL, including the expression level of apoptosis-regulating genes/proteins (Bcl-2, Mcl-1) and microRNAs, have been suggested. In this review, we attempt to provide data concerning the properties of lipoprotein lipase (LPL), as well as to present its prognostic value in CLL. LPL mRNA expression level was able to predict mutational status in a high percentage of CLL cases and high LPL expression was associated with shorter treatment-free survival. Importantly, since LPL activity is low (or absent) in other blood cell types, its expression can be determined by PCR technique in peripheral blood mononuclear cells or in lysed blood samples.
RESUMEN
BRAFV600- and MEK1/2-targeting therapies rarely produce durable response in melanoma patients. We investigated five BRAFV600E melanoma cell lines derived from drug-naïve tumor specimens to assess cell death response to encorafenib (Braftovi), a recently FDA-approved BRAFV600 inhibitor. Drug-naïve cell lines (i) did not harbor damaging alterations in genes encoding core apoptotic machinery, but they differed in (ii) mitochondrial priming as demonstrated by whole-cell BH3 profiling, and (iii) levels of selected anti-apoptotic proteins. Encorafenib modulated the balance between apoptosis-regulating proteins as it upregulated BIM and BMF, and attenuated NOXA, but did not affect the levels of pro-survival proteins except for MCL-1 and BCL-XL in selected cell lines. Induction of apoptosis could be predicted using Dynamic BH3 profiling. The extent of apoptosis was dependent on both (i) cell-intrinsic proximity to the apoptotic threshold (initial mitochondrial priming) and (ii) the abundance of encorafenib-induced BIM (iBIM; drug-induced change in priming). While co-inhibition of MCL-1 and BCL-XL/BCL-2 was indispensable for apoptosis in drug-naïve cells, encorafenib altered cell dependence to MCL-1, and reliance on BCL-XL/BCL-2 was additionally found in cell lines that were highly primed to apoptosis by encorafenib. This translated into robust apoptosis when encorafenib was combined with selective BH3 mimetics. Our study provides a mechanistic insight into the role of proteins from the BCL-2 family in melanoma cell response to targeted therapy, and presents preclinical evidence that (i) MCL-1 is a druggable target to potentiate encorafenib activity, whereas (ii) pharmacological inhibition of BCL-XL/BCL-2 might be relevant but only for a narrow group of encorafenib-treated patients.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Carbamatos/farmacología , Melanoma/tratamiento farmacológico , Fragmentos de Péptidos/farmacología , Neoplasias Cutáneas/tratamiento farmacológico , Sulfonamidas/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Apoptosis/efectos de los fármacos , Carbamatos/uso terapéutico , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Sinergismo Farmacológico , Humanos , Melanoma/genética , Melanoma/patología , Mutación , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/antagonistas & inhibidores , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/uso terapéutico , Dominios y Motivos de Interacción de Proteínas/genética , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Sulfonamidas/uso terapéutico , Proteína X Asociada a bcl-2/genética , Proteína bcl-X/antagonistas & inhibidores , Proteína bcl-X/metabolismoRESUMEN
TYRP1 mRNA is of interest due to its potential non-coding role as a sponge sequestering tumor-suppressive miRs in melanoma. To our knowledge, there is no report on changes in TYRP1 expression in melanomas after development of resistance to targeted therapies. We used patient-derived drug-naïve RASQ61R and BRAFV600E melanoma cell lines. In BRAFV600E melanoma cells, resistance to vemurafenib and trametinib was developed. A time-lapse fluorescence microscope was used to rate proliferation, qRT-PCR and Western blotting were used to assess TYRP1 expression and MITF-M level and activity. A high TYRP1 protein level in RASQ61R cells corresponded with high TYRP1 mRNA level, whereas undetectable TYRP1 protein in BRAFV600E cells was accompanied by medium mRNA level, also in cells carrying NF1R135W variant in addition. TYRP1 expression was MITF-M-independent, since similar transcript status was found in MITF-Mhigh and MITF-Mlow cells. For the first time, we showed that TYRP1 expression remained unaltered in melanoma cells that became resistant to vemurafenib or trametinib, including those cells losing MITF-M. Also drug discontinuation in resistant cells did not substantially affect TYRP1 expression. To verify in vitro results, publicly available microarray data were analyzed. TYRP1 transcript levels stay unaltered in the majority of paired melanoma samples from patients before treatment and after relapse caused by resistance to targeted therapies. As TYRP1 mRNA level remains unaltered in melanoma cells during development of resistance to vemurafenib or trametinib, therapies developed to terminate a sponge activity of TYRP1 transcript may be extended to patients that relapse with resistant disease.
Asunto(s)
Melanoma/genética , Glicoproteínas de Membrana/genética , Mutación/genética , Oxidorreductasas/genética , Proteínas Proto-Oncogénicas B-raf/genética , ARN Mensajero/genética , Neoplasias Cutáneas/genética , Línea Celular Tumoral , Resistencia a Antineoplásicos , Regulación Neoplásica de la Expresión Génica , Humanos , Melanoma/tratamiento farmacológico , Factor de Transcripción Asociado a Microftalmía/metabolismo , Recurrencia Local de Neoplasia , Isoformas de Proteínas/metabolismo , Piridonas/uso terapéutico , Pirimidinonas/uso terapéutico , Neoplasias Cutáneas/tratamiento farmacológico , Vemurafenib/uso terapéuticoRESUMEN
The BCL-2 family of proteins integrates signals that trigger either cell survival or apoptosis. The balance between pro-survival and pro-apoptotic proteins is important for tissue development and homeostasis, while impaired apoptosis contributes to several pathologies and can be a barrier against effective treatment. BCL-w is an anti-apoptotic protein that shares a sequence similarity with BCL-XL, and exhibits a high conformational flexibility. BCL-w level is controlled by a number of signaling pathways, and the repertoire of transcriptional regulators largely depends on the cellular and developmental context. As only a few disease-relevant genetic alterations of BCL2L2 have been identified, increased levels of BCL-w might be a consequence of abnormal activation of signaling cascades involved in the regulation of BCL-w expression. In addition, BCL-w transcript is a target of a plethora of miRNAs. Besides its originally recognized pro-survival function during spermatogenesis, BCL-w has been envisaged in different types of normal and diseased cells as an anti-apoptotic protein. BCL-w contributes to survival of senescent and drug-resistant cells. Its non-apoptotic role in the promotion of cell migration and invasion has also been elucidated. Growing evidence indicates that a high BCL-w level can be therapeutically relevant in neurodegenerative disorders, neuron dysfunctions and after small intestinal resection, whereas BCL-w inhibition can be beneficial for cancer patients. Although several drugs and natural compounds can bi-directionally affect BCL-w level, agents that selectively target BCL-w are not yet available. This review discusses current knowledge on the role of BCL-w in health, non-cancerous diseases and cancer.
Asunto(s)
Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteína bcl-X/metabolismo , Animales , Apoptosis , Humanos , Ratones , Ratones DesnudosRESUMEN
The clinical benefit of MAPK pathway inhibition in BRAF-mutant melanoma patients is limited by the development of acquired resistance. Using drug-naïve cell lines derived from tumor specimens, we established a preclinical model of melanoma resistance to vemurafenib or trametinib to provide insight into resistance mechanisms. Dissecting the mechanisms accompanying the development of resistance, we have shown that (i) most of genetic and non-genetic alterations are triggered in a cell line- and/or drug-specific manner; (ii) several changes previously assigned to the development of resistance are induced as the immediate response to the extent measurable at the bulk levels; (iii) reprogramming observed in cross-resistance experiments and growth factor-dependence restricted by the drug presence indicate that phenotypic plasticity of melanoma cells largely contributes to the sustained resistance. Whole-exome sequencing revealed novel genetic alterations, including a frameshift variant of RBMX found exclusively in phospho-AKThigh resistant cell lines. There was no similar pattern of phenotypic alterations among eleven resistant cell lines, including expression/activity of crucial regulators, such as MITF, AXL, SOX, and NGFR, which suggests that patient-to-patient variability is richer and more nuanced than previously described. This diversity should be considered during the development of new strategies to circumvent the acquired resistance to targeted therapies.