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1.
J Med Virol ; 95(7): e28957, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37465969

RESUMO

Nucleus accumbens-associated protein 1 (NAC1), a transcriptional cofactor, has been found to play important roles in regulating regulatory T cells, CD8+ T cells, and antitumor immunity, but little is known about its effects on T-cell memory. In this study, we found that NAC1 expression restricts memory formation of CD4+ T cells during viral infection. Analysis of CD4+ T cells from wild-type (WT) and NAC1-deficient (-/- ) mice showed that NAC1 is essential for T-cell metabolism, including glycolysis and oxidative phosphorylation, and supports CD4+ T-cell survival in vitro. We further demonstrated that a deficiency of NAC1 downregulates glycolysis and correlates with the AMPK-mTOR pathway and causes autophagy defective in CD4+ T cells. Loss of NAC1 reduced the expression of ROCK1 and the phosphorylation and stabilization of BECLIN1. However, a forced expression of ROCK1 in NAC1-/- CD4+ T cells restored autophagy and the activity of the AMPK-mTOR pathway. In animal experiments, adoptively transferred NAC1-/- CD4+ T cells or NAC1-/- mice challenged with VACV showed enhanced formation of VACV-specific CD4+ memory T cells compared to adoptively transferred WT CD4+ T cells or WT mice. This memory T-cell formation enhancement was abrogated by forcing expression of ROCK1. Our study reveals a novel role for NAC1 as a suppressor of CD4+ T-cell memory formation and suggests that targeting NAC1 could be a new approach to promoting memory CD4+ T-cell development, which is critical for an effective immune response against pathogens.


Assuntos
Proteínas Quinases Ativadas por AMP , Linfócitos T CD8-Positivos , Animais , Camundongos , Proteínas Quinases Ativadas por AMP/metabolismo , Linfócitos T CD4-Positivos , Sobrevivência Celular , Memória Imunológica , Camundongos Endogâmicos C57BL , Serina-Treonina Quinases TOR/metabolismo
2.
Drug Resist Updat ; 56: 100752, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33765484

RESUMO

Immunotherapies such as CAR-T cell transfer and antibody-targeted therapy have produced promising clinical outcomes in patients with advanced and metastatic cancer that are resistant to conventional therapies. However, with increasing use of cancer immunotherapy in clinical treatment, multiple therapy-resistance mechanisms have gradually emerged. The tumor microenvironment (TME), an integral component of cancer, can significantly influence the therapeutic response. Thus, it is worth exploring the potential of TME in modulating therapy resistance, in the hope to devise novel strategies to reinforcing anti-cancer treatments such as immunotherapy. As a crucial recycling process in the complex TME, the role of autophagy in tumor immunity has been increasingly appreciated. Firstly, autophagy in tumor cells can affect their immune response through modulating MHC-I-antigen complexes, thus modulating immunogenic tumor cell death, changing functions of immune cells via secretory autophagy, reducing the NK- and CTL-mediated cell lysis and degradation of immune checkpoint proteins. Secondly, autophagy is critical for the differentiation, maturation and survival of immune cells in the TME and can significantly affect the immune function of these cells, thereby regulating the anti-tumor immune response. Thirdly, alteration of autophagic activity in stromal cells, especially in fibroblasts, can reconstruct the three-dimensional stromal environment and metabolic reprogramming in the TME. A number of studies have demonstrated that optimal induction or inhibition of autophagy may lead to effective therapeutic regimens when combined with immunotherapy. This review discusses the important roles of autophagy in tumor cells, immune cells and stromal cells in the context of tumor immunity, and the potential of combining the autophagy-based therapy with immunotherapy as novel therapeutic approaches against cancer.


Assuntos
Antineoplásicos Imunológicos/farmacologia , Autofagia/fisiologia , Microambiente Tumoral/fisiologia , Autofagia/efeitos dos fármacos , Autofagia/imunologia , Morte Celular/fisiologia , Antígenos de Histocompatibilidade Classe I/efeitos dos fármacos , Humanos , Neoplasias/imunologia , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologia
3.
J Biol Chem ; 294(25): 10006-10017, 2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31101655

RESUMO

Nucleus accumbens-associated protein-1 (NAC1) is a transcriptional repressor encoded by the NACC1 gene, which is amplified and overexpressed in various human cancers and plays critical roles in tumor development, progression, and drug resistance. NAC1 has therefore been explored as a potential therapeutic target for managing malignant tumors. However, effective approaches for effective targeting of this nuclear protein remain elusive. In this study, we identified a core unit consisting of Met7 and Leu90 in NAC1's N-terminal domain (amino acids 1-130), which is critical for its homodimerization and stability. Furthermore, using a combination of computational analysis of the NAC1 dimerization interface and high-throughput screening (HTS) for small molecules that inhibit NAC1 homodimerization, we identified a compound (NIC3) that selectively binds to the conserved Leu-90 of NAC1 and prevents its homodimerization, leading to proteasomal NAC1 degradation. Moreover, we demonstrate that NIC3-mediated down-regulation of NAC1 protein sensitizes drug-resistant tumor cells to conventional chemotherapy and enhances the antimetastatic effect of the antiangiogenic agent bevacizumab both in vitro and in vivo These results suggest that small-molecule inhibitors of NAC1 homodimerization may effectively sensitize cancer cells to some anticancer agents and that NAC1 homodimerization could be further explored as a potential therapeutic target in the development of antineoplastic agents.


Assuntos
Acetamidas/farmacologia , Antineoplásicos/farmacologia , Compostos de Bifenilo/farmacologia , Neoplasias da Mama/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas de Neoplasias/química , Multimerização Proteica/efeitos dos fármacos , Proteínas Repressoras/química , Bibliotecas de Moléculas Pequenas/farmacologia , Inibidores da Angiogênese/farmacologia , Animais , Apoptose , Bevacizumab/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/secundário , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas de Neoplasias/metabolismo , Proteínas Repressoras/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
4.
J Cell Biochem ; 119(1): 691-700, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28636190

RESUMO

As a de-ubiquitin enzyme, ubiquitin C-terminal hydrolase (UCH)-L1 has been shown to be overexpressed in several human cancers. However, the function of UCH-L1 in invasion of breast cancers is still unclear. Here we report that the expression of UCH-L1 is significantly higher in cancer cells with higher invasive ability. While ectopic UCH-L1 expression failed to alter cell proliferation in MCF-7 cells, it caused a significant upregulation of cellular invasion. Furthermore, siRNA mediated knockdown of UCH-L1 led to suppression of invasion in UCH-L1 overexpressing MCF-7 cells. In order to identify molecular mechanisms underlying these observations, a novel in vitro proximity-dependent biotin identification method was developed by fusing UCH-L1 protein with a bacterial biotin ligase (Escherichia coli BirA R118G, BioID). Streptavidin magnetic beads pulldown assay revealed that UCH-L1 can interact with Akt in MCF-7 cells. Pulldown assay with His tagged recombinant UCH-L1 protein and cell lysate from MCF-7 cells further demonstrated that UCH-L1 preferentially binds to Akt2 for Akt activation. Finally, we demonstrated that overexpression of UCH-L1 led to activation of Akt as evidenced by upregulation of phosphorylated Akt. Thus, these findings demonstrated that UCH-L1 promotes invasion of breast cancer cells and might serve as a potential therapeutic target for treatment of human patients with breast cancers.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ubiquitina Tiolesterase/metabolismo , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Células MCF-7 , Invasividade Neoplásica , Fosforilação , Transdução de Sinais , Ubiquitina Tiolesterase/genética , Regulação para Cima
5.
Drug Resist Updat ; 32: 1-15, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-29145974

RESUMO

Patients with breast tumors that do not express the estrogen receptor, the progesterone receptor, nor Her-2/neu are hence termed "triple negatives", and generally have a poor prognosis, with high rates of systemic recurrence and refractoriness to conventional therapy regardless of the choice of adjuvant treatment. Thus, more effective therapeutic options are sorely needed for triple-negative breast cancer (TNBC), which occurs in approximately 20% of diagnosed breast cancers. In recent years, exploiting intrinsic mechanisms of the host immune system to eradicate cancer cells has achieved impressive success, and the advances in immunotherapy have yielded potential new therapeutic strategies for the treatment of this devastating subtype of breast cancer. It is anticipated that the responses initiated by immunotherapeutic interventions will explicitly target and annihilate tumor cells, while at the same time spare normal cells. Various immunotherapeutic approaches have been already developed and tested, which include the blockade of immune checkpoints using neutralizing or blocking antibodies, induction of cytotoxic T lymphocytes (CTLs), adoptive cell transfer-based therapy, and modulation of the tumor microenvironment to enhance the activity of CTLs. One of the most important areas of breast cancer research today is understanding the immune features and profiles of TNBC and devising novel immune-modulatory strategies to tackling TNBC, a subtype of breast cancer notorious for its poor prognosis and its imperviousness to conventional treatments. On the optimal side, one can anticipate that novel, effective, and personalized immunotherapy for TNBC will soon achieve more success and impact clinical treatment of this disease which afflicts approximately 20% of patients with breast cancer. In the present review, we highlight the current progress and encouraging developments in cancer immunotherapy, with a goal to discuss the challenges and to provide future perspectives on how to exploit a variety of new immunotherapeutic approaches including checkpoint inhibitors and neoadjuvant immunotherapy for the treatment of patients with TNBC.


Assuntos
Antineoplásicos/uso terapêutico , Imunoterapia/métodos , Recidiva Local de Neoplasia/terapia , Neoplasias de Mama Triplo Negativas/terapia , Microambiente Tumoral/efeitos dos fármacos , Antineoplásicos/farmacologia , Biomarcadores Tumorais/antagonistas & inibidores , Biomarcadores Tumorais/imunologia , Ensaios Clínicos como Assunto , Terapia Combinada/métodos , Terapia Combinada/tendências , Resistência a Múltiplos Medicamentos/genética , Resistência a Múltiplos Medicamentos/imunologia , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/imunologia , Feminino , Instabilidade Genômica , Humanos , Imunoterapia/tendências , Terapia de Alvo Molecular/métodos , Terapia de Alvo Molecular/tendências , Terapia Neoadjuvante/métodos , Terapia Neoadjuvante/tendências , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/imunologia , Recidiva Local de Neoplasia/patologia , Receptores Imunológicos/antagonistas & inibidores , Receptores Imunológicos/imunologia , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/imunologia , Neoplasias de Mama Triplo Negativas/patologia , Microambiente Tumoral/imunologia
6.
Drug Resist Updat ; 26: 28-42, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27180308

RESUMO

Long non-coding RNAs (lncRNAs) represent a class of non-protein coding transcripts longer than 200 nucleotides that have aptitude for regulating gene expression at the transcriptional, post-transcriptional or epigenetic levels. In recent years, lncRNAs, which are believed to be the largest transcript class in the transcriptomes, have emerged as important players in a variety of biological processes. Notably, the identification and characterization of numerous lncRNAs in the past decade has revealed a role for these molecules in the regulation of cancer cell survival and death. It is likely that this class of non-coding RNA constitutes a critical contributor to the assorted known or/and unknown mechanisms of intrinsic or acquired drug resistance. Moreover, the expression of lncRNAs is altered in various patho-physiological conditions, including cancer. Therefore, lncRNAs represent potentially important targets in predicting or altering the sensitivity or resistance of cancer cells to various therapies. Here, we provide an overview on the molecular functions of lncRNAs, and discuss their impact and importance in cancer development, progression, and therapeutic outcome. We also provide a perspective on how lncRNAs may alter the efficacy of cancer therapy and the promise of lncRNAs as novel therapeutic targets for overcoming chemoresistance. A better understanding of the functional roles of lncRNA in cancer can ultimately translate to the development of novel, lncRNA-based intervention strategies for the treatment or prevention of drug-resistant cancer.


Assuntos
Regulação Neoplásica da Expressão Gênica , Neoplasias/genética , RNA Longo não Codificante , Animais , Antineoplásicos/farmacologia , Sobrevivência Celular/genética , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Transcriptoma
7.
Pharmacol Rev ; 65(4): 1162-97, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23943849

RESUMO

Autophagy, a process of self-digestion of the cytoplasm and organelles through which cellular components are recycled for reuse or energy production, is an evolutionarily conserved response to metabolic stress found in eukaryotes from yeast to mammals. It is noteworthy that autophagy is also associated with various pathophysiologic conditions in which this cellular process plays either a cytoprotective or cytopathic role in response to a variety of stresses such as metabolic, inflammatory, neurodegenerative, and therapeutic stress. It is now generally believed that modulating the activity of autophagy through targeting specific regulatory molecules in the autophagy machinery may impact disease processes, thus autophagy may represent a new pharmacologic target for drug development and therapeutic intervention of various human disorders. Induction or inhibition of autophagy using small molecule compounds has shown promise in the treatment of diseases such as cancer. Depending on context, induction or suppression of autophagy may exert therapeutic effects via promoting either cell survival or death, two major events targeted by therapies for various disorders. A better understanding of the biology of autophagy and the pharmacology of autophagy modulators has the potential for facilitating the development of autophagy-based therapeutic interventions for several human diseases.


Assuntos
Autofagia/fisiologia , Animais , Autofagia/efeitos dos fármacos , Doença , Tratamento Farmacológico , Humanos
8.
Nutr Cancer ; 65(6): 891-9, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23909734

RESUMO

In this study we demonstrated that Triticuside A, one of the flavonoid compounds isolated from wheat bran, induced apoptosis and inhibited proliferation of human breast cancer cells. Triticuside A inhibited the proliferation of human breast cancer cells (MCF-7 and MDA-MB-231) in a dose-dependent manner but barely showed cytotoxicity to the normal human fibroblasts. Triticuside A-induced apoptosis was accompanied by a significant decrease of Mcl-1 and Bcl-2 proteins and by an increase of cleavage of caspases-3, -7, -9, and PARP. Triticuside A also suppressed the level of phospho-Akt and its downstream targets, mTOR and P70 S6 kinase. LY294002, a specific inhibitor of PI3K, significantly enhanced the Triticuside A-induced apoptosis. Moreover LY294002 not only downregulated the level of phospho-Akt but also enhanced the inhibition of Mcl-1 expression when combined with Triticuside A. Our results demonstrate for the first time the specific apoptogenic activity of Triticuside A in tumor cells and involvement of the mitochondrial apoptosis pathway and Akt/mTOR signaling pathway. Thus, Triticuside A may be a potentially useful wheat bran component that can be used for prevention or treatment of breast cancer.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Proliferação de Células/efeitos dos fármacos , Flavonoides/farmacologia , Glicosídeos/farmacologia , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Neoplasias da Mama/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Caspase 7/genética , Caspase 7/metabolismo , Caspase 9/genética , Caspase 9/metabolismo , Linhagem Celular Tumoral , Cromonas/farmacologia , Regulação para Baixo , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Células MCF-7 , Morfolinas/farmacologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo
9.
Biomedicines ; 11(8)2023 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-37626718

RESUMO

Nucleus-accumbens-associated protein-1 (NAC1) is a cancer-related transcriptional factor encoded by the NACC1 gene, which is amplified and overexpressed in various human cancers and has been appreciated as one of the top potential cancer driver genes. NAC1 has therefore been explored as a potential therapeutic target for managing malignant tumors. Here, we show that NAC1 is a negative regulator of NF-κB signaling, and NAC1 depletion enhances the level of the nuclear NF-κB in human melanoma. Furthermore, the inhibition of NF-κB signaling significantly potentiates the antineoplastic activity of the NAC1 inhibition in both the cultured melanoma cells and xenograft tumors. This study identifies a novel NAC1-NF-κB signaling axis in melanoma, offering a promising new therapeutic option to treat melanoma.

10.
Biomedicines ; 11(4)2023 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-37189841

RESUMO

Triple-negative breast cancer (TNBC), characterized by a deficiency in estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor2 (HER2), is among the most lethal subtypes of breast cancer (BC). Nevertheless, the molecular determinants that contribute to its malignant phenotypes such as tumor heterogeneity and therapy resistance, remain elusive. In this study, we sought to identify the stemness-associated genes involved in TNBC progression. Using bioinformatics approaches, we found 55 up- and 9 downregulated genes in TNBC. Out of the 55 upregulated genes, a 5 gene-signature (CDK1, EZH2, CCNB1, CCNA2, and AURKA) involved in cell regeneration was positively correlated with the status of tumor hypoxia and clustered with stemness-associated genes, as recognized by Parametric Gene Set Enrichment Analysis (PGSEA). Enhanced infiltration of immunosuppressive cells was also positively correlated with the expression of these five genes. Moreover, our experiments showed that depletion of the transcriptional co-factor nucleus accumbens-associated protein 1 (NAC1), which is highly expressed in TNBC, reduced the expression of these genes. Thus, the five genes signature identified by this study warrants further exploration as a potential new biomarker of TNBC heterogeneity/stemness characterized by high hypoxia, stemness enrichment, and immune-suppressive tumor microenvironment.

11.
Biochem Pharmacol ; 211: 115533, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37019189

RESUMO

In this study, we uncovered the nuclear export of nucleus accumbens-associated protein-1 (NAC1) as a novel mechanism involved in ovarian cancer resistance to taxanes, the chemotherapeutic drugs commonly used in treatment of this malignancy. We showed that NAC1, a nuclear factor of the BTB/POZ gene family, has a nuclear export signal (NES) at the N terminus (aa 17-28), and this NES critically contributes to the NAC1 nuclear-cytoplasmic shuttling when tumor cells were treated with docetaxel. Mechanistically, the nuclear-exported NAC1 bound to cullin3 (Cul3) and Cyclin B1 via its BTB and BOZ domains respectively, and the cyto-NAC1-Cul3 E3 ubiquitin ligase complex promotes the ubiquitination and degradation of Cyclin B1, thereby facilitating mitotic exit and leading to cellular resistance to docetaxel. We also showed in in vitro and in vivo experiments that TP-CH-1178, a membrane-permeable polypeptide against the NAC1 NES motif, blocked the nuclear export of NAC1, interfered with the degradation of Cyclin B1 and sensitized ovarian cancer cells to docetaxel. This study not only reveals a novel mechanism by which the NAC1 nuclear export is regulated and Cyclin B1 degradation and mitotic exit are impacted by the NAC1-Cul3 complex, but also provides the nuclear-export pathway of NAC1 as a potential target for modulating taxanes resistance in ovarian cancer and other malignancies.


Assuntos
Neoplasias Ovarianas , Proteínas Repressoras , Humanos , Feminino , Transporte Ativo do Núcleo Celular , Docetaxel/farmacologia , Ciclina B1/metabolismo , Proteínas Repressoras/metabolismo , Neoplasias Ovarianas/metabolismo
12.
Biochem Biophys Res Commun ; 424(2): 308-14, 2012 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-22749997

RESUMO

Eukaryotic elongation factor-2 kinase (eEF-2K) is a Ca(2+)/calmodulin-dependent enzyme that negatively regulates protein synthesis. eEF-2K has been shown to be up-regulated in cancer, and to play an important role in cell survival through inhibition of protein synthesis. Post-translational modification of protein synthesis machinery is important for its regulation and could be critical for survival of cancer cells encountering stress. The purpose of our study was to examine the regulation of eEF-2K during stress with a focus on the roles of phosphorylation in determining the stability of eEF-2K. We found that stress conditions (nutrient deprivation and hypoxia) increase eEF-2K protein. mRNA levels are only transiently increased and shortly return to normal, while eEF-2K protein levels continue to increase after further exposure to stress. A seemingly paradoxical decrease in eEF-2K stability was found when glioma cells were subjected to stress despite increased protein expression. We further demonstrated that phosphorylation of eEF-2K differentially affects the enzyme's turnover under both normal and stress conditions, as evidenced by the different half-lives of phosphorylation-defective mutants of eEF-2K. We further found that the eEF-2K site (Ser398) phosphorylated by AMPK is pivotal to the protein's stability, as the half-life of S398A mutant increases to greater than 24h under both normal and stress conditions. These data indicate that eEF-2K is regulated at multiple levels with phosphorylation playing a critical role in the enzyme's turnover under stressful conditions. The complexity of eEF-2K phosphorylation highlights the intricacies of protein synthesis control during cellular stress.


Assuntos
Quinase do Fator 2 de Elongação/metabolismo , Processamento de Proteína Pós-Traducional , Estresse Fisiológico , Linhagem Celular Tumoral , Quinase do Fator 2 de Elongação/genética , Estabilidade Enzimática , Humanos , Mutação , Fosforilação , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/antagonistas & inibidores
13.
World J Gastrointest Oncol ; 14(12): 2329-2339, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36568940

RESUMO

BACKGROUND: Nucleus accumbens-1 (NAC-1) is highly expressed in a variety of tumors, including colon cancer, and is closely associated with tumor recurrence, metastasis, and invasion. AIM: To determine whether and how NAC-1 affects antitumor immunity in colon cancer. METHODS: NAC-1-siRNA was transfected into RKO colon cancer cells to knock down NAC expression; tumor cells with or without knockdown of NAC-1 were treated with CD8+ T cells to test their cytocidal effect. The level of the immune checkpoint programmed death receptor-1 ligand (PD-L1) in colon cancer cells with or without knockdown of NAC-1 was analyzed using Quantitative real-time polymerase chain reaction and Western blotting. A double luciferase reporter assay was used to examine the effects of NAC-1 on the transcription of PD-L1. Mice bearing MC-38-OVA colon cancer cells expressing NAC-shRNA or control-shRNA were treated with OT-I mouse CD8+ T cells to determine the tumor response to immunotherapy. Immune cells in the tumor tissues were analyzed using flow cytometry. NAC-1, PD-L1 and CD8+ T cells in colon cancer specimens from patients were examined using immunohistochemistry staining. RESULTS: Knockdown of NAC-1 expression in colon cancer cells significantly enhanced the cytocidal effect of CD8+ T cells in cell culture experiments. The sensitizing effect of NAC-1 knockdown on the antitumor action of cytotoxic CD8+ T cells was recapitulated in a colon cancer xenograft animal model. Furthermore, knockdown of NAC-1 in colon cancer cells decreased the expression of PD-L1 at both the mRNA and protein levels, and this effect could be rescued by transfection of an RNAi-resistant NAC-1 expression plasmid. In a reporter gene assay, transient expression of NAC-1 in colon cancer cells increased the promoter activity of PD-L1, indicating that NAC-1 regulates PD-L1 expression at the transcriptional level. In addition, depletion of tumoral NAC-1 increased the number of CD8+ T cells but decreased the number of suppressive myeloid-derived suppressor cells and regulatory T cells. CONCLUSION: Tumor expression of NAC-1 is a negative determinant of immunotherapy.

14.
J Immunother Cancer ; 10(3)2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35347072

RESUMO

BACKGROUND: Immune checkpoint blockade (ICB) targeting programmed death ligand-1 (PD-L1)/programmed cell death protein-1 (PD-1) pathway has become an attractive strategy for cancer treatment; however, unsatisfactory efficacy has limited its clinical benefits. Therefore, a more comprehensive understanding of the regulation of PD-L1 expression is essential for developing more effective cancer immunotherapy. Recent studies have revealed the important roles of eukaryotic elongation factor 2 kinase (eEF2K) in promoting epithelial-mesenchymal transition (EMT), angiogenesis, tumor cell migration and invasion; nevertheless, the exact role of eEF2K in the regulation of tumor immune microenvironment (TIME) remains largely unknown. METHODS: In this study, we used a cohort of 38 patients with melanoma who received anti-PD-1 treatment to explore the association between eEF2K expression and immunotherapy efficacy against melanoma. Immunoprecipitation-mass spectrometry analysis and in vitro assays were used to examine the role and molecular mechanism of eEF2K in regulating PD-L1 expression. We also determined the effects of eEF2K on tumor growth and cytotoxicity of CD8+ T cells in TIME in a mouse melanoma model. We further investigated the efficacy of the eEF2K inhibition in combination with anti-PD-1 treatment in vivo. RESULTS: High eEF2K expression is correlated with better therapeutic response and longer survival in patients with melanoma treated with PD-1 monoclonal antibody (mAb). Moreover, eEF2K protein expression is positively correlated with PD-L1 protein expression. Mechanistically, eEF2K directly bound to and inactivated glycogen synthase kinase 3 beta (GSK3ß) by phosphorylating it at serine 9 (S9), leading to PD-L1 protein stabilization and upregulation, and subsequently tumor immune evasion. Knockdown of eEF2K decreased PD-L1 expression and enhanced CD8+ T cell activity, thus dramatically attenuating murine B16F10 melanoma growth in vivo. Clinically, p-GSK3ß/S9 expression is positively correlated with the expressions of eEF2K and PD-L1, and the response to anti-PD-1 immunotherapy. Furthermore, eEF2K inhibitor, NH125 treatment or eEF2K knockdown enhanced the efficacy of PD-1 mAb therapy in a melanoma mouse model. CONCLUSIONS: Our results suggest that eEF2K may serve as a biomarker for predicting therapeutic response and prognosis in patients receiving anti-PD-1 therapy, reveal a vital role of eEF2K in regulating TIME by controlling PD-L1 expression and provide a potential combination therapeutic strategy of eEF2K inhibition with ICB therapy.


Assuntos
Antígeno B7-H1 , Melanoma , Animais , Anticorpos Monoclonais/uso terapêutico , Linfócitos T CD8-Positivos/metabolismo , Quinase do Fator 2 de Elongação , Glicogênio Sintase Quinase 3 beta , Humanos , Melanoma/patologia , Camundongos , Receptor de Morte Celular Programada 1/uso terapêutico , Microambiente Tumoral
15.
Sci Adv ; 8(5): eabl9783, 2022 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-35108044

RESUMO

eEF-2K has important roles in stress responses and cellular metabolism. We report here a previously unappreciated but critical role of eEF-2K in regulating the fate and cytocidal activity of CD8+ T cells. CD8+ T cells from eEF-2K KO mice were more proliferative but had lower survival than their wild-type counterparts after their activation, followed by occurrence of premature senescence and exhaustion. eEF-2K KO CD8+ T cells were more metabolically active and showed hyperactivation of the Akt-mTOR-S6K pathway. Loss of eEF-2K substantially impaired the activity of CD8+ T cells. Furthermore, the antitumor efficacy and tumor infiltration of the CAR-CD8+ T cells lacking eEF-2K were notably reduced as compared to the control CAR-CD8+ T cells. Thus, eEF-2K is critically required for sustaining the viability and function of cytotoxic CD8+ T cells, and therapeutic augmentation of this kinase may be exploited as a novel approach to reinforcing CAR-T therapy against cancer.


Assuntos
Linfócitos T CD8-Positivos , Quinase do Fator 2 de Elongação/metabolismo , Neoplasias , Animais , Camundongos , Neoplasias/terapia , Fatores de Alongamento de Peptídeos
16.
Viruses ; 14(8)2022 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-36016335

RESUMO

Nucleus accumbens-associated protein 1 (NAC1) is a transcription co-factor that has been shown to possess multiple roles in stem cell and cancer biology. However, little is known about its roles in regulation of the immune system. In the current study, we observed that expression of NAC1 impacted the survival of CD8+ T cells in vitro. NAC1-/- CD8+ T cells displayed lower metabolism, including reduced glycolysis and oxidative phosphorylation. In vivo, compared with wild-type (WT) mice, NAC1-/- mice produced a lower response to vaccinia virus (VACV) infection, and viral antigen (Ag)-specific CD8+ T cells decreased more slowly. Additionally, we observed that the NAC1-/- mice demonstrated a stronger memory formation of viral Ag-specific CD8+ T cells post-viral infection. Mechanically, we identified that compared with WT CD8+ T cells, the Interferon Regulatory Factor 4 (IRF4), a key transcription factor in T cell development, was highly expressed in NAC1-/- CD8+ T cells, insinuating that IRF4 could be a critical regulatory target of NAC1 in the memory formation of CD8+ T cells. Our results indicate that NAC1 restrains the memory formation of CD8+ T cells by modulating IRF4, and targeting NAC1 may be exploited as a new approach to boosting CD8+ T cell memory.


Assuntos
Linfócitos T CD8-Positivos , Viroses , Animais , Memória Imunológica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Vaccinia virus , Viroses/metabolismo
17.
J Immunother Cancer ; 10(9)2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36150745

RESUMO

BACKGROUND: T cell-mediated antitumor immunity has a vital role in cancer prevention and treatment; however, the immune-suppressive tumor microenvironment (TME) constitutes a significant contributor to immune evasion that weakens antitumor immunity. Here, we explore the relationship between nucleus accumbens-associated protein-1 (NAC1), a nuclear factor of the BTB (broad-complex, Tramtrack, bric a brac)/POZ (Poxvirus, and Zinc finger) gene family, and the TME. METHODS: Adoptive cell transfer (ACT) of mouse or human tumor antigen (Ag)-specific CD8+ cytotoxic T lymphocytes (CTLs) was tested in an immunocompetent or immunodeficient mouse model of melanoma with or without expression of NAC1. The effects of NAC1 expression on immune evasion in tumor cells were assessed in vitro and in vivo. CRISPR/Cas9, glycolysis analysis, retroviral transduction, quantitative real-time PCR, flow cytometric analysis, immunoblotting, database analyses were used to screen the downstream target and underlying mechanism of NAC1 in tumor cells. RESULTS: Tumorous expression of NAC1 negatively impacts the CTL-mediated antitumor immunity via lactate dehydrogenase A (LDHA)-mediated suppressive TME. NAC1 positively regulated the expression of LDHA at the transcriptional level, which led to higher accumulation of lactic acid in the TME. This inhibited the cytokine production and induced exhaustion and apoptosis of CTLs, impairing their cell-killing ability. In the immunocompetent and immunodeficient mice, NAC1 depleted melanoma tumors grew significantly slower and had an elevated infiltration of tumor Ag-specific CTLs following ACT, compared with the control groups. CONCLUSIONS: Tumor expression of NAC1 contributes substantially to immune evasion through its regulatory role in LDHA expression and lactic acid production. Thus, therapeutic targeting of NAC1 warrants further exploration as a potential strategy to reinforce cancer immunotherapy, such as the ACT of CTLs.


Assuntos
Evasão da Resposta Imune , Lactato Desidrogenase 5 , Melanoma , Proteínas do Tecido Nervoso , Proteínas Repressoras , Animais , Antígenos de Neoplasias , Citocinas , Humanos , Lactato Desidrogenase 5/metabolismo , Ácido Láctico , Melanoma/imunologia , Camundongos , Camundongos SCID , Proteínas de Neoplasias , Proteínas do Tecido Nervoso/genética , Proteínas Repressoras/genética , Microambiente Tumoral
18.
Sci Adv ; 8(26): eabo0183, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35767626

RESUMO

We report here that nucleus accumbens-associated protein-1 (NAC1), a nuclear factor of the Broad-complex, Tramtrack, Bric-a-brac/poxvirus and zinc finger (BTB/POZ) gene family, is a negative regulator of FoxP3 in regulatory T cells (Tregs) and a critical determinant of immune tolerance. Phenotypically, NAC1-/- mice showed substantial tolerance to the induction of autoimmunity and generated a larger amount of CD4+ Tregs that exhibit a higher metabolic profile and immune-suppressive activity, increased acetylation and expression of FoxP3, and slower turnover of this transcription factor. Treatment of Tregs with the proinflammatory cytokines interleukin-1ß or tumor necrosis factor-α induced a robust up-regulation of NAC1 but evident down-regulation of FoxP3 as well as the acetylated FoxP3. These findings imply that NAC1 acts as a trigger of the immune response through destabilization of Tregs and suppression of tolerance induction, and targeting of NAC1 warrants further exploration as a potential tolerogenic strategy for treatment of autoimmune disorders.

19.
Biochem Biophys Res Commun ; 414(1): 129-34, 2011 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-21945617

RESUMO

Elongation factor-2 kinase (eEF-2 kinase, also known as calmodulin-dependent protein kinase III), is a unique calcium/calmodulin-dependent enzyme that inhibits protein synthesis by phosphorylating and inactivating elongation factor-2 (eEF-2). We previously reported that expression/activity of eEF-2 kinase was up-regulated in several types of malignancies including Gliomas, and was associated with response of tumor cells to certain therapeutic stress. In the current study, we sought to determine whether eEF-2 kinase expression affected sensitivity of glioma cells to treatment with tumor the necrosis factor-related apoptosis-inducing ligand (TRAIL), a targeted therapy able to induce apoptosis in cancer cells but causes no toxicity in most normal cells. We found that inhibition of eEF-2 kinase by RNA interference (RNAi) or by a pharmacological inhibitor (NH125) enhanced TRAIL-induced apoptosis in the human glioma cells, as evidenced by an increase in apoptosis in the tumor cells treated with eEF-2 kinase siRNA or the eEF-2 kinase inhibitor. We further demonstrated that sensitization of tumor cells to TRAIL was accompanied by a down-regulation of the anti-apoptotic protein, Bcl-xL, and that overexpression of Bcl-xL could abrogate the sensitizing effect of inhibiting eEF-2 kinase on TRAIL. The results of this study may help devise a new therapeutic strategy for enhancing the efficacy of TRAIL against malignant glioma by targeting eEF-2 kinase.


Assuntos
Neoplasias Encefálicas/enzimologia , Resistencia a Medicamentos Antineoplásicos , Quinase do Fator 2 de Elongação/antagonistas & inibidores , Glioma/enzimologia , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Linhagem Celular Tumoral , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Quinase do Fator 2 de Elongação/genética , Marcação de Genes , Humanos , Interferência de RNA , Proteína bcl-X/antagonistas & inibidores , Proteína bcl-X/biossíntese
20.
Front Mol Biosci ; 8: 727863, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34532346

RESUMO

Eukaryotic Elongation Factor-2 Kinase (eEF2K) acts as a negative regulator of protein synthesis, translation, and cell growth. As a structurally unique member of the alpha-kinase family, eEF2K is essential to cell survival under stressful conditions, as it contributes to both cell viability and proliferation. Known as the modulator of the global rate of protein translation, eEF2K inhibits eEF2 (eukaryotic Elongation Factor 2) and decreases translation elongation when active. eEF2K is regulated by various mechanisms, including phosphorylation through residues and autophosphorylation. Specifically, this protein kinase is downregulated through the phosphorylation of multiple sites via mTOR signaling and upregulated via the AMPK pathway. eEF2K plays important roles in numerous biological systems, including neurology, cardiology, myology, and immunology. This review provides further insights into the current roles of eEF2K and its potential to be explored as a therapeutic target for drug development.

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