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Solid tumors frequently present a heterogeneous tumor microenvironment. Because tumors have the potential to proliferate quickly, the consequence is a reduction in the nutrients, a reduction in the pH (<6.8), and a hypoxic environment. Although it is often assumed that tumor clones show a similar growth rate with little variations in nutrient consumption, the present study shows how growth-specific rate (µ), the specific rates of glucose, lactate, and glutamine consumption (qS), and the specific rates of lactate and glutamate production (qP) of 2D-cultured lung tumor cells are affected by changes in their environment. We determined in lung tumor cells (A427, A549, Calu-1, and SKMES-1) the above mentioned kinetic parameters during the exponential phase under different culture conditions, varying the predominant carbon source, pH, and oxygen tension. MCF-7 cells, a breast tumor cell line that can consume lactate, and non-transformed fibroblast cells (MRC-5) were included as controls. We also analyzed how cell-cycle progression and the amino acid transporter CD98 expression were affected. Our results show that: (1) In glucose presence, µ increased, but qS Glucose and qP Lactate decreased when tumor cells were cultured under acidosis as opposed to neutral conditions; (2) most lung cancer cell lines consumed lactate under normoxia or hypoxia; (3) although qS Glutamine diminished under hypoxia or acidosis, it slightly increased in lactate presence, a finding that was associated with CD98 upregulation; and (4) under acidosis, G0/G1 arrest was induced in A427 cancer cells, although this phenomenon was significantly increased when glucose was changed by lactate as the predominant carbon-source. Hence, our results provide an understanding of metabolic responses that tumor cells develop to survive under stressful conditions, providing clues for developing promising opportunities to improve traditional cancer therapies.
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Tumor cells must resist the host's immune system while maintaining growth under harsh conditions of acidity and hypoxia, which indicates that tumors are more robust than normal tissue. Immunotherapeutic agents have little effect on solid tumors, mostly because of the tumor density and the difficulty of penetrating deeply into the tissue to achieve the theoretical therapeutic effect. Various therapeutic strategies targeting the tumor microenvironment (TME) have been developed. Immunometabolic disorders play a dominant role in treatment resistance at both the TME and host levels. Understanding immunometabolic factors and their treatment potential may be a way forward for tumor immunotherapy. Here, we summarize the metabolism of substances that affect tumor progression, the crosstalk between the TME and immunosuppression, and some potential tumor-site targets. We also summarize the progress and challenges of tumor immunotherapy.
Assuntos
Neoplasias , Humanos , Neoplasias/tratamento farmacológico , Imunoterapia , Terapia de Imunossupressão , Tolerância Imunológica , Hipóxia , Microambiente TumoralRESUMO
The development of cancers is often linked to the alteration of essential redox processes, and therefore, oxidoreductases involved in such mechanisms can be considered as attractive molecular targets for the development of new therapeutic strategies. On the other hand, for more than two decades, transition metals derivatives have been leading the research on drugs as alternatives to platinum-based treatments. The success of such compounds is particularly due to their attractive redox kinetics properties, favorable oxidation states, as well as routes of action different to interactions with DNA, in which redox interactions are crucial. For instance, the activity of oxidoreductases such as PHD2 (prolyl hydroxylase domain-containing protein) which can regulate angiogenesis in tumors, LDH (lactate dehydrogenase) related to glycolysis, and enzymes, such as catalases, SOD (superoxide dismutase), TRX (thioredoxin) or GSH (glutathione) involved in controlling oxidative stress, can be altered by metal effectors. In this review, we wish to discuss recent results on how transition metal complexes have been rationally designed to impact on redox processes, in search for effective and more specific cancer treatments.
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In this review, we report on the complexity of breast cancer stem cells as key cells in the emergence of a chemoresistant tumor phenotype, and as a result, the appearance of distant metastasis in breast cancer patients. The search for mechanisms that increase sensitivity to chemotherapy and also allow activation of the tumor-specific immune response is of high priority. As we observed throughout this review, natural products isolated or in standardized extracts, such as P2Et or others, could act synergistically, increasing tumor sensitivity to chemotherapy, recovering the tumor microenvironment, and participating in the induction of a specific immune response. This, in turn, would lead to the destruction of cancer stem cells and the decrease in metastasis. Source of Data: Relevant studies were found using the following keywords or medical subject headings (MeSH) in PubMed, and Google Scholar: "immune response" and "polyphenols" and "natural products" and "BCSC" and "therapy" and "metabolism" and "immunogenic cell death." The focus was primarily on the most recent scientific publication.
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Altered cell metabolism is a hallmark of cancer and critical for its development. Particularly, activation of one-carbon metabolism in tumor cells can sustain oncogenesis while contributing to epigenetic changes and metabolic adaptation during tumor progression. We assessed whether increased one-carbon metabolism activity is a metabolic feature of invasive ductal carcinoma (IDC). Differences in the metabolic profile between biopsies from IDC (n = 47) and its adjacent tissue (n = 43) and between biopsies from different breast cancer subtypes were assessed by gas spectrometry in targeted (Biocrates Life Science ® ) and untargeted approaches, respectively. The metabolomics data were statistically treated using MetaboAnalyst 4.0, SIMCA P+ (version 12.01), Statistica 10 software and t test with p < 0.05. The Cancer Genome Atlas breast cancer dataset was also assessed to validate the metabolomic profile of IDC. Our targeted metabolomics analysis showed distinct metabolomics profiles between IDC and adjacent tissue, where IDC displayed a comparative enrichment of metabolites involved in one-carbon metabolism (serine, glycine, threonine, and methionine) and a predicted increase in the activity of pathways that receive and donate carbon units (i.e., folate, methionine, and homocysteine). In addition, the targeted and untargeted metabolomics analyses showed similar metabolomics profiles between breast cancer subtypes. The gene set enrichment analysis identified different transcription-related functions between IDC and non-tumor tissues that involved one-carbon metabolism. Our data suggest that one-carbon metabolism may be a central pathway in IDC and even in general breast tumors, representing a potential target for its treatment and prevention.
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Resumen Las leucemias agudas son trastornos clonales originados a partir de células hematopoyéticas primitivas multipotenciales que se caracterizan por la proliferación, diferenciación y maduración aberrante de células progenitoras leucémicas como resultado de varios eventos genéticos y epigenéticos. Aunque en la actualidad se han implementado diferentes esquemas de quimioterapia para mejorar el pronóstico de los pacientes, las leucemias agudas representan una malignidad hematológica con pobre desenlace clínico y bajas tasas de supervivencia en pacientes pediátricos y adultos Colombianos. Uno de los principales obstáculos para el tratamiento exitoso del cáncer es el desarrollo de resistencia a los medicamentos durante la quimioterapia y la enfermedad recurrente. En el estudio de la biología de las células tumorales, se reconoce que los diversos cambios oncogénicos y la evolución clonal que sufren las células tumorales, son cambios biológicos que les confieren mecanismos de resistencia a la quimioterapia convencional, que a su vez se traducen en un incremento en las tasas de mortalidad y/o el aumento de recaídas en los pacientes que padecen esta enfermedad. Por lo tanto, el estudio de los mecanismos empleados por las células leucémicas para escapar del efecto citotóxico del tratamiento empleado para combatir la enfermedad es un objetivo primordial de la investigación en cáncer. En este contexto, el objetivo del presente artículo es hacer una revisión detallada de los avances más recientes en la comprensión de los mecanismos involucrados en la resistencia tumoral en leucemias, haciendo especial énfasis en el papel que desempeñan las células madre leucémicas y el metabolismo tumoral en la quimiorresistencia de este grupo de enfermedades. El conocimiento de los mecanismos de resistencia tumoral, así como el entendimiento detallado de las interacciones entre las células normales y leucémicas en el microambiente de la médula ósea, son prometedores blancos terapéuticos de las leucemias agudas.
Abstract Acute leukemias (AL) are clonal disorders originated from multi-potent immature hematopoietic cells and are characterized by aberrant proliferation, differentiation and maturation of leukemic progenitor cells as a result of multiple genetic and epigenetic events. Even though different chemotherapy regimens have been implemented to improve patient prognostic, acute leukemias represent a hematological malignancy with poor clinical outcome and low survival rates in pediatric and adult patients in Colombia. One of the main obstacles to the success of cancer treatment is the development of drug resistance during chemotherapy and the recurrent disease. In the study of tumor cells biology, it is now known that clonal evolution and oncogenic changes of tumor cells are biological properties that confer resistance mechanisms to conventional chemotherapy, which in turn translate into an increased mortality rate and/or an increased risk of relapse in leukemia patients. Therefore, the study of mechanisms that leukemic cells employ to avoid the cytotoxic effects of some chemotherapeutics is a main objective of cancer research. In this context, the objective of the current paper is to give a detailed information about recent advances in mechanisms involved in leukemic resistance, with special emphasis on the role of leukemic stem cells theory and tumor metabolism.
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Humanos , Leucemia , Sobrevivência , Metabolismo , Células-Tronco , Sobrevida , NeoplasiasRESUMO
BACKGROUND: High oxidative stress as defined by hydroxyl and peroxyl activity is often found in the stroma of human breast cancers. Oxidative stress induces stromal catabolism, which promotes cancer aggressiveness. Stromal cells exposed to oxidative stress release catabolites such as lactate, which are up-taken by cancer cells to support mitochondrial oxidative phosphorylation. The transfer of catabolites between stromal and cancer cells leads to metabolic heterogeneity between these cells and increased cancer cell proliferation and reduced apoptosis in preclinical models. N-Acetylcysteine (NAC) is an antioxidant that reduces oxidative stress and reverses stromal catabolism and stromal-carcinoma cell metabolic heterogeneity, resulting in reduced proliferation and increased apoptosis of cancer cells in experimental models of breast cancer. The purpose of this clinical trial was to determine if NAC could reduce markers of stromal-cancer metabolic heterogeneity and markers of cancer cell aggressiveness in human breast cancer. METHODS: Subjects with newly diagnosed stage 0 and I breast cancer who were not going to receive neoadjuvant therapy prior to surgical resection were treated with NAC before definitive surgery to assess intra-tumoral metabolic markers. NAC was administered once a week intravenously at a dose of 150 mg/kg and 600 mg twice daily orally on the days not receiving intravenous NAC. Histochemistry for the stromal metabolic markers monocarboxylate transporter 4 (MCT4) and caveolin-1 (CAV1) and the Ki67 proliferation assay and TUNEL apoptosis assay in carcinoma cells were performed in pre- and post-NAC specimens. RESULTS: The range of days on NAC was 14-27 and the mean was 19 days. Post-treatment biopsies showed significant decrease in stromal MCT4 and reduced Ki67 in carcinoma cells. NAC did not significantly change stromal CAV1 and carcinoma TUNEL staining. NAC was well tolerated. CONCLUSIONS: NAC as a single agent reduces MCT4 stromal expression, which is a marker of glycolysis in breast cancer with reduced carcinoma cell proliferation. This study suggests that modulating metabolism in the tumor microenvironment has the potential to impact breast cancer proliferation.
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Acetilcisteína/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Carcinoma Ductal de Mama/tratamento farmacológico , Carcinoma Intraductal não Infiltrante/tratamento farmacológico , Sequestradores de Radicais Livres/uso terapêutico , Mastectomia , Adulto , Apoptose , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/metabolismo , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/metabolismo , Carcinoma Intraductal não Infiltrante/patologia , Carcinoma Papilar/tratamento farmacológico , Carcinoma Papilar/metabolismo , Carcinoma Papilar/patologia , Caveolina 1/metabolismo , Proliferação de Células , Feminino , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Antígeno Ki-67/metabolismo , Pessoa de Meia-Idade , Transportadores de Ácidos Monocarboxílicos/metabolismo , Proteínas Musculares/metabolismo , Terapia Neoadjuvante , Estadiamento de Neoplasias , Projetos Piloto , Células Estromais/metabolismo , Resultado do Tratamento , Microambiente TumoralRESUMO
PURPOSE: Thiamine-dependent enzymes (TDEs) linking glycolysis with the tricarboxylic acid cycle (TCA) pyruvate dehydrogenase (PDH), of the pentose phosphate pathway transketolases (TKTs), the TCA alpha-ketoglutarate deydrogenase (KGDH)/2-oxoglutarate dehydrogenase (OGDH) complex, and the amino acid catabolism branched-chain alpha-ketoacid dehydrogenase (BCKDH) complex are crucial factors for tumor metabolism. The expression of these enzymes has not been analyzed for carcinogenesis of oral squamous cell carcinoma (OSCC) with special focus on new targeted metabolic therapies as yet. METHODS: TDEs PDH, KGDH (OGDH), and BCKDH were analyzed in normal oral mucosa (n = 14), oral precursor lesions (simple hyperplasia, n = 21; squamous intraepithelial neoplasia, SIN I-III, n = 35), and OSCC specimen (n = 46) by immunohistochemistry and western blot (WB) analysis in OSCC tumor cell lines. RESULTS: Although the total numbers of PDH and KGDH (OGDH) positive samples decreased in OSCC, both enzymes were significantly overexpressed in the carcinogenesis of OSCC compared with normal tissue. BCKDH has been demonstrated to be significantly overexpressed in the carcinogenesis of OSCC. Specificity of the antibodies was confirmed by WB analysis. CONCLUSIONS: This is the first study showing increased expression of TDEs in OSCC. Metabolic targeting of TDEs (including TKTs) by antagonistic compounds like oxythiamine or oxybenfothiamine may be a useful strategy to sensitize cancer cells to common OSCC cancer therapies.
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3-Metil-2-Oxobutanoato Desidrogenase (Lipoamida)/metabolismo , Carcinoma de Células Escamosas/enzimologia , Complexo Cetoglutarato Desidrogenase/metabolismo , Neoplasias Bucais/enzimologia , Complexo Piruvato Desidrogenase/metabolismo , Tiamina/metabolismo , Western Blotting , Carcinogênese/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Masculino , Transcetolase/metabolismoRESUMO
Células tumorais apresentam uma autonomia metabólica aumentada em comparação a células não-transformadas, incorporando nutrientes e metabolizando-os através de vias que suportam o seu crescimento e proliferação. O foco deste trabalho foi a enzima glutaminase, a qual processa glutamina em glutamato para posterior produção de alfa-cetoglutarato pela enzima glutamato desidrogenase, reabastecendo o ciclo do TCA e suportando seu funcionamento e geração de metabólitos essenciais para a síntese de macromoléculas. O gene GLS1 codifica para as isoformas glutaminase kidney-type (KGA) e glutaminase C (GAC). Estas proteínas apresentam outros domínios além do catalítico, e, no caso da KGA, repetições do tipo ankirin, sabidamente envolvidas em contatos proteínas-proteínas. Os objetivos deste projeto foram de encontrar parceiros de interação para a glutaminase kidney-type (KGA) e avaliar o impacto desta interação para o metabolismo tumoral. Um candidato inicialmente avaliado, a Aldolase A, não foi confirmado como parceiro de interação. Outro candidato, a BNIP-H, apesar de ter sido mostrado interagir com a KGA em células nervosas, não mostrou indícios de interação com a KGA em linhagem de células de câncer de mama. Por fim, estudos de duplo-híbrido em levedura revelaram o receptor nuclear PPARγ (Peroxisome proliferator-activated receptor gamma) como forte candidato a parceiro de interação. Realizou-se um mapeamento dos domínios responsáveis pela interação entre estas duas proteínas, também por duplo híbrido, tendo sido identificado o domínio LBD da proteína PPARγ como envolvido na interação. Mesmo estudos realizados com fragmento da KGA, apesar de incompletos, mostraram que a interação não ocorre pelo domínio carboxi-terminal da enzima. Ensaios de anisotropia de fluorescência com as proteínas KGA e PPARγ purificadas indicaram que a interação é favorecida pela presença do produto da reação glutaminolítica, glutamato, e apresenta um Kd de 4,6 ± 0,5 μM...
Tumor cells have an increased metabolic autonomy compared to non-transformed cells, metabolizing nutrients and incorporating them through pathways that support cell growth and proliferation. The focus of this study was the glutaminase enzyme, which processes glutamine to glutamate for subsequent production of alpha-ketoglutarate, by the glutamate dehydrogenase enzyme, replenishing TCA cycle and bearing its function and the generation of metabolites essential for the synthesis of macromolecules. The gene GLS1 codes for the isoforms kidney-type glutaminase (KGA) and glutaminase C (GAC). These proteins exhibit other domains besides the catalytic, and in the case of KGA, ankirin repeats, known to be involved in protein-protein contacts. The goal of this project was to investigate potential interacting partners of KGA and contextualize the interaction within the metabolic demands of tumor cells. A candidate initially evaluated, the Aldolase A, was not confirmed as a partner of interaction. Another candidate, the BNIP-H, despite having been shown to interact with the KGA in nervous cells, showed no evidence of interaction with KGA in one tested breast cancer cell lines. Finally, yeast two-hybrid studies revealed the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) as a strong interaction partner candidate. We mapped the domains responsible for the interaction between these two proteins, also by two-hybrid and identified the LBD domain of PPARγ as involved in the interaction. The same studies with KGA fragments, although incomplete, showed that the interaction did not involve the carboxy-terminal domain of the enzyme. KGA and PPARγ proteins were expressed in E. coli, purified and their interaction was analyzed by pull-down, fluorescence anisotropy, electrophoresis under native conditions, gel filtration chromatography and crosslinking...