RESUMEN

Exportin5 (Exp5) is the major miRNA nuclear export factor and recognizes structural features of pre-miRNA hairpins, while it also exports other minihelix-containing RNAs. In Drosophila, Exp5 is suggested to play a major role in tRNA export because the gene encoding the canonical tRNA export factor Exportin-t is missing in its genome. To understand molecular functions of fly Exp5, we studied the Exp5/RNA interactome in the cell line S2R + using the crosslinking and immunoprecipitation (CLIP) technology. The CLIP experiment captured known substrates such as tRNAs and miRNAs and detected candidates of novel Exp5 substrates including various mRNAs and long non-coding RNAs (lncRNAs). Some mRNAs and lncRNAs enriched PAR-CLIP tags compared to their expression levels, suggesting selective binding of Exp5 to them. Intronless mRNAs tended to enrich PAR-CLIP tags; therefore, we proposed that Exp5 might play a role in the export of specific classes of mRNAs/lncRNAs. This result suggested that Drosophila Exp5 might have a wider variety of substrates than initially thought. Surprisingly, Exp5 CLIP reads often contained sequences corresponding to the flanking 5'-leaders and 3'-trailers of tRNAs, which were thought to be removed prior to nuclear export. In fact, we found pre-tRNAs before end-processing were present in the cytoplasm, supporting the idea that tRNA end-processing is a cytoplasmic event. In summary, our results provide a genome-wide list of Exp5 substrate candidates and suggest that flies may lack a mechanism to distinguish pre-tRNAs with or without the flanking sequences.

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BACKGROUND: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. As liver cancer often presents no noticeable symptoms in its early stages, most patients are diagnosed at an advanced stage, complicating treatment. Therefore, the identification of new biomarkers is crucial for the early detection and treatment of HCC. Research on exportin-5 (XPO5) could offer new avenues for early diagnosis and improve treatment strategies. AIM: To explore the role of XPO5 in HCC progression and its potential as a prognostic biomarker. METHODS: This study assessed XPO5 mRNA expression in HCC using The Cancer Genome Atlas, TIMER, and International Cancer Genome Consortium databases, correlating it with clinical profiles and disease progression. We performed in vitro experiments to examine the effect of XPO5 on liver cell growth. Gene Set Enrichment Analysis, Kyoto Encyclopedia of Genes and Genomes, and Gene Ontology were used to elucidate the biological roles and signaling pathways. We also evaluated XPO5's impact on immune cell infiltration and validated its prognostic potential using machine learning. RESULTS: XPO5 was significantly upregulated in HCC tissues, correlating with tumor grade, T-stage, and overall survival, indicating poor prognosis. Enrichment analyses linked high XPO5 expression with tumor immunity, particularly CD4 T cell memory activation and macrophage M0 infiltration. Drug sensitivity tests identified potential therapeutic agents such as MG-132, paclitaxel, and WH-4-023. Overexpression of XPO5 in HCC cells, compared to normal liver cells, was confirmed by western blotting and quantitative real-time polymerase chain reaction. The lentiviral transduction-mediated knockdown of XPO5 significantly reduced cell proliferation and metastasis. Among the various machine learning algorithms, the C5.0 decision tree algorithm achieved accuracy rates of 95.5% in the training set and 92.0% in the validation set. CONCLUSION: Our analysis shows that XPO5 expression is a reliable prognostic indicator for patients with HCC and is significantly associated with immune cell infiltration.

RESUMEN

OBJECTIVE: To report long-term efficacy and safety of selinexor maintenance therapy in adults with TP53 wild-type (TP53wt) stage IV or recurrent endometrial cancer (EC) who achieved partial remission (PR) or complete remission (CR) following chemotherapy. METHODS: Analysis of the prespecified, exploratory subgroup of patients with TP53wt EC from the phase 3 SIENDO study was performed. Progression-free survival (PFS) benefit in patients with TP53wt EC and across other patient subgroups were exploratory endpoints. Safety and tolerability were also assessed. RESULTS: Of the 263 patients enrolled in the SIENDO trial, 113 patients had TP53wt EC; 70/113 (61.9%) had TP53wt/proficient mismatch repair (pMMR) EC, and 29/113 (25.7%) had TP53wt/deficient mismatch repair (dMMR) EC. As of April 1, 2024, the median PFS (mPFS) for TP53wt patients who received selinexor compared with placebo was 28.4 versus 5.2 months (36.8-month follow-up, HR 0.44; 95% CI 0.27-0.73). A benefit in mPFS was seen with selinexor versus placebo regardless of MMR status (patients with TP53wt/pMMR EC: 39.5 vs 4.9 months, HR 0.36; 95% CI 0.19-0.71; patients with TP53wt/dMMR EC: 13.1 vs 3.7 months, HR 0.49; 95% CI 0.18-1.34). Selinexor treatment was generally manageable, with no new safety signals identified. CONCLUSION: In the phase 3 SIENDO study, selinexor maintenance therapy showed a promising efficacy signal and a manageable safety profile in the prespecified subgroup of patients with TP53wt EC who achieved a PR or CR following chemotherapy. These results are being further evaluated in an ongoing randomized phase 3 trial (NCT05611931).

Asunto(s)

Neoplasias Endometriales , Hidrazinas , Recurrencia Local de Neoplasia , Triazoles , Proteína p53 Supresora de Tumor , Humanos , Femenino , Triazoles/administración & dosificación , Triazoles/efectos adversos , Triazoles/uso terapéutico , Persona de Mediana Edad , Hidrazinas/efectos adversos , Hidrazinas/administración & dosificación , Hidrazinas/uso terapéutico , Anciano , Proteína p53 Supresora de Tumor/genética , Neoplasias Endometriales/tratamiento farmacológico , Neoplasias Endometriales/genética , Neoplasias Endometriales/patología , Recurrencia Local de Neoplasia/tratamiento farmacológico , Adulto , Estudios de Seguimiento , Supervivencia sin Progresión , Anciano de 80 o más Años , Quimioterapia de Mantención/métodos , Estadificación de Neoplasias

RESUMEN

Myeloid-derived suppressor cells (MDSCs) are a main driver of immunosuppression in tumors. Understanding the mechanisms that determine the development and immunosuppressive function of these cells could provide new therapeutic targets to improve antitumor immunity. Here, using preclinical murine models, we discovered that exportin 1 (XPO1) expression is upregulated in tumor MDSCs and that this upregulation is induced by IL-6-induced STAT3 activation during MDSC differentiation. XPO1 blockade transforms MDSCs into T-cell-activating neutrophil-like cells, enhancing the antitumor immune response and restraining tumor growth. Mechanistically, XPO1 inhibition leads to the nuclear entrapment of ERK1/2, resulting in the prevention of ERK1/2 phosphorylation following the IL-6-mediated activation of the MAPK signaling pathway. Similarly, XPO1 blockade in human MDSCs induces the formation of neutrophil-like cells with immunostimulatory functions. Therefore, our findings revealed a critical role for XPO1 in MDSC differentiation and suppressive functions; exploiting these new discoveries revealed new targets for reprogramming immunosuppressive MDSCs to improve cancer therapeutic responses.

Asunto(s)

Transporte Activo de Núcleo Celular , Proteína Exportina 1 , Carioferinas , Células Supresoras de Origen Mieloide , Receptores Citoplasmáticos y Nucleares , Animales , Humanos , Ratones , Diferenciación Celular , Línea Celular Tumoral , Núcleo Celular/metabolismo , Tolerancia Inmunológica , Interleucina-6/metabolismo , Carioferinas/metabolismo , Sistema de Señalización de MAP Quinasas , Ratones Endogámicos C57BL , Células Supresoras de Origen Mieloide/inmunología , Células Supresoras de Origen Mieloide/metabolismo , Neoplasias/inmunología , Neoplasias/patología , Receptores Citoplasmáticos y Nucleares/metabolismo , Factor de Transcripción STAT3/metabolismo

RESUMEN

Global aging is a tendency of the world, as is the increasing prevalence of diabetes, and the two are closely linked. In our early research, Enteromorpha prolifera oligosaccharide (EPO) possesses the excellent ability of anti-oxidative, anti-inflammatory, and anti-diabetic. We aim to further explore the deeper mechanism of how EPO delays aging and regulates glycometabolism. EPO effectively impacts crotonylation procession to enhance glucose metabolism and reduce cell senescence in aging diabetic rats. Crotonylation modification of XPO1 influences the expression of critical genes, including p53, CDK1, and CCNB1, which affect cell cycle regulation and aging. Additionally, EPO improves glucose metabolism by inhibiting the crotonylation modification of HSPA8-K126 and activating the AKT pathway. EPO promotes crotonylation of histones in intestinal cells, influencing the aging process by increasing the butyric acid-producing bacteria Ruminococcaceae. The observed enhancement in pyrimidine metabolism underscores EPO's potential role in regulating intestinal health, presenting a promising avenue for delaying aging. In summary, our findings affirm EPO as a naturally bioactive ingredient with significant potential for anti-aging and antidiabetic interventions.

Asunto(s)

Diabetes Mellitus Tipo 2 , Hipoglucemiantes , Oligosacáridos , Animales , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Oligosacáridos/farmacología , Oligosacáridos/metabolismo , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Masculino , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/tratamiento farmacológico , Envejecimiento/metabolismo , Envejecimiento/efectos de los fármacos , Senescencia Celular/efectos de los fármacos , Ratas Sprague-Dawley , Ratas , Humanos , Microbioma Gastrointestinal/efectos de los fármacos

RESUMEN

BACKGROUND: The liver is anatomically divided into eight segments based on the distribution of Glisson's triad. However, the molecular mechanisms underlying each segment and its association with hepatocellular carcinoma (HCC) heterogeneity are not well understood. In this study, our objective is to conduct a comprehensive multiomics profiling of the segmentation atlas in order to investigate potential subtypes and therapeutic approaches for HCC. METHODS: A high throughput liquid chromatography-tandem mass spectrometer strategy was employed to comprehensively analyse proteome, lipidome and metabolome data, with a focus on segment-resolved multiomics profiling. To classify HCC subtypes, the obtained data with normal reference profiling were integrated. Additionally, potential therapeutic targets for HCC were identified using immunohistochemistry assays. The effectiveness of these targets were further validated through patient-derived organoid (PDO) assays. RESULTS: A multiomics profiling of 8536 high-confidence proteins, 1029 polar metabolites and 3381 nonredundant lipids was performed to analyse the segmentation atlas of HCC. The analysis of the data revealed that in normal adjacent tissues, the left lobe was primarily involved in energy metabolism, while the right lobe was associated with small molecule metabolism. Based on the normal reference atlas, HCC patients with segment-resolved classification were divided into three subtypes. The C1 subtype showed enrichment in ribosome biogenesis, the C2 subtype exhibited an intermediate phenotype, while the C3 subtype was closely associated with neutrophil degranulation. Furthermore, using the PDO assay, exportin 1 (XPO1) and 5-lipoxygenase (ALOX5) were identified as potential targets for the C1 and C3 subtypes, respectively. CONCLUSION: Our extensive analysis of the segmentation atlas in multiomics profiling defines molecular subtypes of HCC and uncovers potential therapeutic strategies that have the potential to enhance the prognosis of HCC.

Asunto(s)

Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/genética , Humanos , Masculino , Multiómica

RESUMEN

Acute myeloid leukemia (AML) patients with DNA methyltransferase 3A (DNMT3A) mutation display poor prognosis, and targeted therapy is not available currently. Our previous study identified increased expression of Exportin1 (XPO1) in DNMT3AR882H AML patients. Therefore, we further investigated the therapeutic effect of XPO1 inhibition on DNMT3AR882H AML. Three types of DNMT3AR882H AML cell lines were generated, and XPO1 was significantly upregulated in all DNMT3AR882H cells compared with the wild-type (WT) cells. The XPO1 inhibitor selinexor displayed higher potential in the inhibition of proliferation, promotion of apoptosis, and blockage of the cell cycle in DNMT3AR882H cells than WT cells. Selinexor also significantly inhibited the proliferation of subcutaneous tumors in DNMT3AR882H AML model mice. Primary cells with DNMT3A mutations were more sensitive to selinexor in chemotherapy-naive AML patients. RNA sequencing of selinexor treated AML cells revealed that the majority of metabolic pathways were downregulated after selinexor treatment, with the most significant change in the glutathione metabolic pathway. Glutathione inhibitor L-Buthionine-(S, R)-sulfoximine (BSO) significantly enhanced the apoptosis-inducing effect of selinexor in DNMT3AWT/DNMT3AR882H AML cells. In conclusion, our work reveals that selinexor displays anti-leukemia efficacy against DNMT3AR882H AML via downregulating glutathione pathway. Combination of selinexor and BSO provides novel therapeutic strategy for AML treatment.

Asunto(s)

ADN (Citosina-5-)-Metiltransferasas , ADN Metiltransferasa 3A , Proteína Exportina 1 , Glutatión , Hidrazinas , Carioferinas , Leucemia Mieloide Aguda , Mutación , Receptores Citoplasmáticos y Nucleares , Triazoles , Humanos , Animales , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Carioferinas/antagonistas & inhibidores , Carioferinas/genética , Ratones , Receptores Citoplasmáticos y Nucleares/antagonistas & inhibidores , Receptores Citoplasmáticos y Nucleares/genética , ADN (Citosina-5-)-Metiltransferasas/antagonistas & inhibidores , ADN (Citosina-5-)-Metiltransferasas/genética , Glutatión/metabolismo , Hidrazinas/farmacología , Hidrazinas/uso terapéutico , Triazoles/farmacología , Triazoles/uso terapéutico , Ensayos Antitumor por Modelo de Xenoinjerto , Regulación hacia Abajo/efectos de los fármacos , Línea Celular Tumoral , Femenino , Masculino , Apoptosis/efectos de los fármacos , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Proliferación Celular/efectos de los fármacos

RESUMEN

OBJECTIVE: Multiple myeloma cells resist standard therapies due to overexpression of the transport protein, exportin 1. Selinexor is a novel drug that targets the Exportin 1 protein in these cells. DATA SOURCE: A comprehensive search was done, and data showing the efficacy and safety of selinexor in relapsed/refractory multiple myeloma was collected using PubMed, Google Scholar, and clincialtrials.gov. DATA SUMMARY: Results from the clinical trials STORM, BOSTON, and STOMP were included. Parts I and II of the STORM trial revealed a progression-free survival (PFS) of 4.7 and 3.7 months, a median duration of response of 6.2 and 4.4 months, and an overall survival of 7.3 and 8.4 months, respectively. BOSTON trial's SVd arm (selinexor, bortezomib, and dexamethasone) had a median follow-up period of 13.2 months and an mPFS of 13.93 months. The Vd arm (bortezomib and dexamethasone) had a median follow-up duration of 16.5 months and an mPFS of 9.46 months. The STOMP trial is still active and has limited data available. The SKd arm (selinexor, carfilzomib, and dexamethasone) reported an overall response rate of 66.7% in patients with triple refractory multiple myeloma, and 82% in patients with high-risk cytogenetics. The SPd arm (selinexor, pomalidomide, and dexamethasone) shows an overall response rate of 54.30% in pomalidomide naïve-nonrefractory, 35.70% in pomalidomide refractory and 60% in those dosed at RP2D. SRd arm (selinexor, lenalidomide, and dexamethasone) shows an overall response rate of 91.7% in lenalidomide naïve and 12.5% in lenalidomide refractory patients. SVd (selinexor, bortezomib, and dexamethasone) arm reported an overall response rate of 63% in all patients while the SDd arm (selinexor, daratumumab, and dexamethasone) showed an overall response rate of 73%. CONCLUSION: To improve the outcome of patients with relapsed/refractory multiple myeloma, it is critical to develop new therapies, assess potential therapeutic synergies, and overcome drug resistance by determining the efficacy of multiple myeloma therapies across multiple disease subgroups.

Asunto(s)

Antineoplásicos , Hidrazinas , Mieloma Múltiple , Triazoles , Humanos , Antineoplásicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Bortezomib/uso terapéutico , Dexametasona/uso terapéutico , Resistencia a Antineoplásicos , Proteína Exportina 1 , Hidrazinas/uso terapéutico , Carioferinas/antagonistas & inhibidores , Mieloma Múltiple/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Supervivencia sin Progresión , Receptores Citoplasmáticos y Nucleares , Triazoles/uso terapéutico , Ensayos Clínicos como Asunto

RESUMEN

Multiple myeloma is an incurable hematological malignancy. Although the continuous development of therapeutic drugs such as proteasome inhibitors and immune modulators, as well as chimeric antigen receptor T-cell (CAR-T) therapy, has improved the prognosis in recent years, some patients are still drug-resistant, presenting as refractory and recurrent disease with limited treatment options. Selinexor, a first-in-class oral selective nuclear export protein inhibitor, binds to and inhibits nuclear export protein XPO-1 to function, leading to the accumulation of tumor suppressor proteins in the nucleus and selective apoptosis of cancer cells. It has shown controllable toxicity and good efficacy in the treatment of recurrent and refractory multiple myeloma. This article discusses the anti-tumor mechanism of selinexor, its clinical research progress, and adverse reactions.

RESUMEN

Recent advances in the study of virus-cell interactions have improved our understanding of how viruses that replicate their genomes in the nucleus (e.g., retroviruses, hepadnaviruses, herpesviruses, and a subset of RNA viruses) hijack cellular pathways to export these genomes to the cytoplasm where they access virion egress pathways. These findings shed light on novel aspects of viral life cycles relevant to the development of new antiviral strategies and can yield new tractable, virus-based tools for exposing additional secrets of the cell. The goal of this review is to summarize defined and emerging modes of virus-host interactions that drive the transit of viral genomes out of the nucleus across the nuclear envelope barrier, with an emphasis on retroviruses that are most extensively studied. In this context, we prioritize discussion of recent progress in understanding the trafficking and function of the human immunodeficiency virus type 1 Rev protein, exemplifying a relatively refined example of stepwise, cooperativity-driven viral subversion of multi-subunit host transport receptor complexes.

RESUMEN

In eukaryotic cells, the spatial distribution between cytoplasm and nucleus is essential for cell homeostasis. This dynamic distribution is selectively regulated by the nuclear pore complex (NPC), which allows the passive or energy-dependent transport of proteins between these two compartments. Viruses possess many strategies to hijack nucleocytoplasmic shuttling for the benefit of their viral replication. Here, we review how viruses interfere with the karyopherin CRM1 that controls the nuclear export of protein cargoes. We analyze the fact that the viral hijacking of CRM1 provokes are-localization of numerous cellular factors in a suitable place for specific steps of viral replication. While CRM1 emerges as a critical partner for viruses, it also takes part in antiviral and inflammatory response regulation. This review also addresses how CRM1 hijacking affects it and the benefits of CRM1 inhibitors as antiviral treatments.

Asunto(s)

Carioferinas , Virus , Transporte Activo de Núcleo Celular , Carioferinas/metabolismo , Virus/genética , Citoplasma/metabolismo , Antivirales/metabolismo , Cromosomas/metabolismo , Núcleo Celular/metabolismo

RESUMEN

BACKGROUND: The maturation of microRNAs (miRNAs) successively undergoes Drosha, Dicer, and Argonaute -mediated processing, however, the intricate regulations of the individual miRNA maturation are largely unknown. Retinoid x receptor alpha (RXRα) belongs to nuclear receptors that regulate gene transcription by binding to DNA elements, however, whether RXRα binds to miRNAs to exert physiological functions is not known. RESULTS: In this work, we found that RXRα directly binds to the precursor of miR-103 (pre-miR-103a-2) via its DNA-binding domain with a preferred binding sequence of AGGUCA. The binding of RXRα inhibits the processing of miR-103 maturation from pre-miR-103a-2. Mechanistically, RXRα prevents the nuclear export of pre-miR-103a-2 for further processing by inhibiting the association of exportin-5 with pre-miR-103a-2. Pathophysiologically, the negative effect of RXRα on miR-103 maturation correlates to the positive effects of RXRα on the expression of Dicer, a target of miR-103, and on the inhibition of breast cancer. CONCLUSIONS: Our findings unravel an unexpected role of transcription factor RXRα in specific miRNA maturation at post-transcriptional level through pre-miRNA binding, and present a mechanistic insight regarding RXRα role in breast cancer progression.

Asunto(s)

MicroARNs , Receptores Citoplasmáticos y Nucleares , Factores de Transcripción , Proteínas Argonautas , MicroARNs/genética

RESUMEN

BACKGOUND: Selinexor is an orally available selective inhibitor of exportin-1 that has offered a new treatment option in relapsed or refractory myeloma (RRMM) either in combination with dexamethasone (Sd) or with bortezomib and dexamethasone (SVd). PATIENTS-METHODS: We evaluated the efficacy and toxicity of selinexor combinations in the real world, post progression therapies and their outcomes. The analysis included 44 patients with RRMM treated with Sd (N = 21, 48%) or SVd (N = 23, 52%). RESULTS: On intent-to-treat, response rate (ORR) among all treated patients was 29.5% (13/44, of which CR: 2, VGPR: 3, PR:8); ORR was 35% for SVd and 24% for Sd. Median PFS was 3.0 months for all; 6.9 months for responders (≥PR),2.7 months for Sd and 3.4 months for SVd treated patients. In univariate analysis, serum albumin <3.5 g/dl and LDH >ULN were associated with worse PFS (P = .001 and P = .032, respectively).The OS of the whole cohort exceeded one year while serum albumin <3.5 gr/dl and LDH>ULN were associated with worse OS. After progression to Sd/SVd, 20 patients received further therapy; on ITT, the ORR was 40% (8/20) and the subsequent PFS was 3.4 months. The most common adverse events were fatigue, thrombocytopenia and nausea, while the most recorded grade 3 or 4 side effect was thrombocytopenia; 56% (25/44) of patients required dose reduction, however, this was not associated with inferior PFS. CONCLUSION: In conclusion, selinexor-based therapy provides an additional treatment option in the real word setting and with appropriate dosing and toxicity management a subset of patients may have significant benefit.

Asunto(s)

Mieloma Múltiple , Trombocitopenia , Humanos , Mieloma Múltiple/tratamiento farmacológico , Dexametasona/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Albúmina Sérica/uso terapéutico , Trombocitopenia/inducido químicamente

RESUMEN

BACKGROUND: In lung cancer, overexpression of nuclear export proteins can result in inactivation of critical tumor suppressor proteins and cell-cycle regulators. Selective suppression of nuclear export proteins has immunomodulatory activities. Here, clinical safety and early efficacy data are presented on the combination of pembrolizumab and an oral selective nuclear export inhibitor, selinexor, for the treatment of metastatic non-small cell lung cancer (mNSCLC). METHODS: The primary objective of this prospective investigator-initiated study was to determine the safety and tolerability of selinexor in combination with pembrolizumab in patients with mNSCLC. Secondary objectives included determination of objective tumor response rate, disease control rate, and progression-free survival duration. RESULTS: A total of 17 patients were included in the final analysis. Fifteen (88%) received more than two lines of prior systemic therapy and 10 (59%) had prior exposure to anti-PD-1/programmed death-ligand 1 (PD-L1) therapy. The median age was 67.5 years. Ten patients had grade ≥3 adverse events related to selinexor treatment. Responses to treatment occurred in patients who did and did not undergo previous anti-PD-1/PD-L1 therapy and in patients with activating driver mutations. The median overall survival and progression-free survival were 11.4 months (95% CI, 3.4-19.8 months) and 3.0 months (95% CI, 1.7-5.7 months), respectively. The overall response rate was 18% and the 6-month disease control rate was 24%. CONCLUSIONS: Selinexor in combination with pembrolizumab demonstrated promising antitumor activity in patients with mNSCLC, including those who had previously received anti-PD-1/PD-L1 therapy. The therapy-related toxic effects were consistent with the prior safety data for both drugs, and no overlapping toxic effects were observed. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02419495. PLAIN LANGUAGE SUMMARY: New strategies to prevent or reverse resistance to immune checkpoint inhibitors are under investigation. Selective inhibitors of nuclear export proteins, such as selinexor, can induce restoration of tumor-suppressing pathways and induce potent immunomodulatory activities. This article contains the clinical safety and early efficacy data on the combination of pembrolizumab and selinexor in treatment of metastatic non-small cell lung cancer.

Asunto(s)

Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Anciano , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/patología , Antígeno B7-H1 , Estudios Prospectivos

RESUMEN

Nuclear epidermal growth factor receptor (EGFR) has been shown to be correlated with drug resistance and a poor prognosis in patients with cancer. Previously, we have identified a tripartite nuclear localization signal (NLS) within EGFR. To comprehensively determine the functions and underlying mechanism of nuclear EGFR and its clinical implications, we aimed to explore the nuclear export signal (NES) sequence of EGFR that is responsible for interacting with the exportins. We combined in silico prediction with site-directed mutagenesis approaches and identified a putative NES motif of EGFR, which is located in amino acid residues 736-749. Mutation at leucine 747 (L747) in the EGFR NES led to increased nuclear accumulation of the protein via a less efficient release of the exportin CRM1. Interestingly, L747 with serine (L747S) and with proline (L747P) mutations were found in both tyrosine kinase inhibitor (TKI)-treated and -naïve patients with lung cancer who had acquired or de novo TKI resistance and a poor outcome. Reconstituted expression of the single NES mutant EGFRL747P or EGFRL747S, but not the dual mutant along with the internalization-defective or NLS mutation, in lung cancer cells promoted malignant phenotypes, including cell migration, invasiveness, TKI resistance, and tumor initiation, supporting an oncogenic role of nuclear EGFR. Intriguingly, cells with germline expression of the NES L747 mutant developed into B cell lymphoma. Mechanistically, nuclear EGFR signaling is required for sustaining nuclear activated STAT3, but not for Erk. These findings suggest that EGFR functions are compartmentalized and that nuclear EGFR signaling plays a crucial role in tumor malignant phenotypes, leading to tumorigenesis in human cancer.

RESUMEN

miRNAs, small non-coding RNAs that regulate gene expression, are involved in various pathological processes, including viral infections. Virus infections may interfere with the miRNA pathway through the inhibition of genes involved in miRNA biogenesis. A reduction in the number and the levels of miRNAs expressed in nasopharyngeal swabs of patients with severe COVID-19 was lately observed by us, pointing towards the potential of miRNAs as possible diagnostic or prognostic biomarkers for predicting outcomes among patients with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. The objective of the present study was to investigate whether SARS-CoV-2 infection influences the expression levels of messenger RNAs (mRNAs) of key genes involved in miRNA biogenesis. mRNA levels of AGO2, DICER1, DGCR8, DROSHA, and Exportin-5 (XPO5) were measured by quantitative reverse-transcription polymerase chain reaction (RT-qPCR) in nasopharyngeal swab specimens from patients with COVID-19 and controls, as well as in cells infected with SARS-CoV-2 in vitro. Our data showed that the mRNA expression levels of AGO2, DICER1, DGCR8, DROSHA, and XPO5 were not significantly different in patients with severe COVID-19 when compared to patients with non-severe COVID-19 and controls. Similarly, the mRNA expression of these genes was not affected by SARS-CoV-2 infection in NHBE and Calu-3 cells. However, in Vero E6 cells, AGO2, DICER1, DGCR8, and XPO5 mRNA levels were slightly upregulated 24 h after infection with SARS-CoV-2. In conclusion, we did not find evidence for downregulation of mRNA levels of miRNA biogenesis genes during SARS-CoV-2 infection, neither ex vivo nor in vitro.

Asunto(s)

COVID-19 , MicroARNs , Humanos , MicroARNs/genética , MicroARNs/metabolismo , COVID-19/genética , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Proteínas de Unión al ARN/metabolismo , ARN Mensajero/genética , Ribonucleasa III/genética , Ribonucleasa III/metabolismo , ARN Helicasas DEAD-box/genética , ARN Helicasas DEAD-box/metabolismo , Carioferinas/genética

RESUMEN

Extracellular vesicles (EVs) are membrane-enclosed subcellular structures released by all cell types. EVs have important roles in both cellular homeostasis and intercellular communication. Recent progress in the field revealed substantial heterogeneity of EVs even within the size-based EV categories. Here we addressed the question whether the exportin-1 (XPO1)-mediated nuclear export of RNAs contributed to the EV heterogeneity. Size-based populations were separated from the conditioned media of three cell lines (U937, THP-1 and 5/4E8) in steady-state condition. The effects of activation and leptomycin B treatment (to inhibit the XPO1-mediated nuclear export of RNAs) were also tested in the case of the two monocytic cell lines. Agilent Pico and Small chips were used to characterize RNAs, fragment analysis was performed, and EV-associated miRNAs were tested by Taqman assays. As expected, we found the highest small RNA/total RNA ratio and the lowest rRNA/total RNA proportion in small EVs (~ 50-150 nm). Profiles of the small RNAs within different size-based EV categories significantly differed based on the activation status of the EV releasing cells. Leptomycin B had a differential inhibition on the tested small RNAs in EVs, even within the same EV size category. A similar heterogeneity of the EV miRNA content was observed upon cellular activation and nuclear export inhibition. Here we complement the already existing knowledge on EV heterogeneity by providing evidence that the RNA cargo varies depending on the EV size-based category, the releasing cell type, the functional status of the releasing cells and the exportin-1-mediated nuclear export of RNAs.

Asunto(s)

Vesículas Extracelulares , MicroARNs , Animales , Humanos , Ratones , Transporte Activo de Núcleo Celular , Comunicación Celular , Vesículas Extracelulares/metabolismo , Carioferinas/genética , Carioferinas/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Proteína Exportina 1

RESUMEN

Acute myeloid leukemia (AML) represents 80% of acute leukemia in adults and is characterized by clonal expansion of hematopoietic stem cells secondary to genomic mutations, rendering a selective growth advantage to the mutant clones. NPM1mut is found in around 30% of AML and clinically presents with leukocytosis, high blast percentage and extramedullary involvement. Considered as a "gate-keeper" mutation, NPM1mut appears to be a "first hit" in the process of leukemogenesis and development of overt leukemia. Commonly associated with other mutations (e.g., FLT 3, DNMT3A, TET2, SF3B1), NPM1 mutation in AML has an important role in diagnosis, prognosis, treatment and post-treatment monitoring. Several novel therapies targeting NPM1 are being developed in various clinical phases with demonstration of efficacy. In this review, we summarize the pathophysiology of the NPM1 gene mutation in AML, clinical implications and the novel targeted therapies to date.

RESUMEN

XPO1 (Exportin-1) is the nuclear export protein responsible for the normal shuttling of several proteins and RNA species between the nucleocytoplasmic compartment of eukaryotic cells. XPO1 recognizes the nuclear export signal (NES) of its cargo proteins to facilitate its export. Alterations of nuclear export have been shown to play a role in oncogenesis in several types of solid tumour and haematologic cancers. Over more than a decade, there has been substantial progress in targeting nuclear export in cancer using selective XPO1 inhibitors. This has resulted in recent approval for the first-in-class drug selinexor for use in relapsed, refractory multiple myeloma and diffuse large B-cell lymphoma (DLBCL). Despite these successes, not all patients respond effectively to XPO1 inhibition and there has been lack of biomarkers for response to XPO1 inhibitors in the clinic. Using haematologic malignancy cell lines and samples from patients with myelodysplastic neoplasms treated with selinexor, we have identified XPO1, NF-κB(p65), MCL-1 and p53 protein levels as protein markers of response to XPO1 inhibitor therapy. These markers could lead to the identification of response upon XPO1 inhibition for more accurate decision-making in the personalized treatment of cancer patients undergoing treatment with selinexor.

Asunto(s)

Neoplasias Hematológicas , Mieloma Múltiple , Humanos , Carioferinas/genética , Transporte Activo de Núcleo Celular , Neoplasias Hematológicas/tratamiento farmacológico , Neoplasias Hematológicas/genética

RESUMEN

Antiretroviral therapy (ART) reduces human immunodeficiency virus type 1 (HIV-1) infection, but selection of treatment-refractory variants remains a major challenge. HIV-1 encodes 16 canonical proteins, a small number of which are the singular targets of nearly all antiretrovirals developed to date. Cellular factors are increasingly being explored, which may present more therapeutic targets, more effectively target certain aspects of the viral replication cycle, and/or limit viral escape. Unlike most other positive-sense RNA viruses that encode at least one helicase, retroviruses are limited to the host repertoire. Accordingly, HIV-1 subverts DEAD-box helicase 3X (DDX3X) and numerous other cellular helicases of the Asp-Glu-x-Asp/His (DExD/H)-box family to service multiple aspects of its replication cycle. Here we review DDX3X and other DExD/H-box helicases in HIV-1 replication and their inhibition.

Asunto(s)

ARN Helicasas DEAD-box , Infecciones por VIH , VIH-1 , Humanos , Infecciones por VIH/tratamiento farmacológico , VIH-1/metabolismo , Replicación Viral/genética