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Nucleosomes are the basic compaction unit of chromatin and nucleosome structure and their higher-order assemblies regulate genome accessibility. Many post-translational modifications alter nucleosome dynamics, nucleosome-nucleosome interactions, and ultimately chromatin structure and gene expression. Here, we investigate the role of two post-translational modifications associated with actively transcribed regions, H3K36me3 and H4K5/8/12/16ac, in the contexts of tri-nucleosome arrays that provide a tractable model system for quantitative single-molecule analysis, while enabling us to probe nucleosome-nucleosome interactions. Direct visualization by AFM imaging reveals that H3K36me3 and H4K5/8/12/16ac nucleosomes adopt significantly more open and loose conformations than unmodified nucleosomes. Similarly, magnetic tweezers force spectroscopy shows a reduction in DNA outer turn wrapping and nucleosome-nucleosome interactions for the modified nucleosomes. The results suggest that for H3K36me3 the increased breathing and outer DNA turn unwrapping seen in mononucleosomes propagates to more open conformations in nucleosome arrays. In contrast, the even more open structures of H4K5/8/12/16ac nucleosome arrays do not appear to derive from the dynamics of the constituent mononucleosomes, but are driven by reduced nucleosome-nucleosome interactions, suggesting that stacking interactions can overrule DNA breathing of individual nucleosomes. We anticipate that our methodology will be broadly applicable to reveal the influence of other post-translational modifications and to observe the activity of nucleosome remodelers.
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Histonas , Nucleosomas , Procesamiento Proteico-Postraduccional , Nucleosomas/metabolismo , Nucleosomas/química , Histonas/metabolismo , Histonas/química , Epigénesis Genética , Código de Histonas , ADN/metabolismo , ADN/química , Conformación de Ácido Nucleico , Metilación , Microscopía de Fuerza Atómica/métodosRESUMEN
BACKGROUND: This study evaluates the outcomes of fibular intramedullary nails (IMNs) compared to traditional plates and screws (PS) in the surgical treatment of unstable ankle injuries in patients aged ≥65 years. METHOD: We conducted a retrospective study involving 32 elderly patients with unstable ankle fractures treated with IMNs from 2010 to 2022. A comparison was made with 125 case-control patients treated with PS during the same period. Outcomes compared included postoperative wound and nonwound complications, surgical reduction, union rates, implant removal rates, and the Olerud Molander Ankle Score (OMAS) at a minimum follow-up of 2 years. RESULTS: The IMN group had a higher incidence of high-energy injuries, open fractures, concomitant surgery, and perioperative transfusion requirements than the PS group. Additionally, the IMN group developed fewer wound-related (3.1% vs 20% in the PS group, P = .043) and non-wound-related complications (18.8% vs 39.2% in the PS group, P = .030). Both groups had similar initial weightbearing restrictions, fracture union times, mean OMAS scores, rates of malunion or nonunion, and delayed implant removal times. Notably, there were significant differences in the quality and adequacy of mortise alignment between the groups (good: 53.1% in IMN group vs 79.2% in PS group, fair: 46.9% in IMN group vs 20.8% in PS group, P = .006). CONCLUSION: Although the IMN group had an inferior outcome in the quality and adequacy of mortise reduction compared with the PS group, elderly patients with ankle fractures treated with IMN showed comparable functional outcomes to those treated with PS but with lower complication rates. Future research in this area will provide vital information for developing optimal treatment strategies, thereby improving the overall care of elderly patients with ankle fractures.
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Fracturas de Tobillo , Clavos Ortopédicos , Placas Óseas , Fijación Intramedular de Fracturas , Humanos , Estudios Retrospectivos , Fracturas de Tobillo/cirugía , Anciano , Fijación Intramedular de Fracturas/métodos , Fijación Intramedular de Fracturas/instrumentación , Masculino , Femenino , Anciano de 80 o más Años , Peroné/lesiones , Peroné/cirugía , Complicaciones Posoperatorias , Estudios de Casos y Controles , Fijación Interna de Fracturas/métodos , Fijación Interna de Fracturas/instrumentaciónRESUMEN
PURPOSE: Intramedullary nailing is the preferred internal fixation technique for the treatment of subtrochanteric fractures because of its biomechanical advantages. However, no definitive conclusion has been reached regarding whether combined cable cerclage is required during intramedullary nailing treatment. This study was performed to compare the clinical effects of intramedullary nailing with cerclage and non-cerclage wiring in the treatment of irreducible spiral subtrochanteric fractures. METHODS: Patients with subtrochanteric fractures admitted to our center from January 2013 to December 2021 were retrospectively analyzed. The patients were enrolled in the case-control study according to the inclusion and exclusion criteria and divided into the non-cerclage group and the cerclage group. The patients' clinical data, including the operative time, intraoperative blood loss, hospital stay, reoperation rate, fracture union time, and Harris hip score, were compared between these 2 groups. Categorical variables were compared using Chi-square or Fisher's exact test. Continuous variables with normal distribution were presented as mean ± standard deviation and analyzed with Student's t-test. Non-normally distributed variables were expressed as median (Q1, Q3) and assessed using the Mann-Whitney test. A p value < 0.05 was considered significant. RESULTS: In total, 69 patients were included in the study (35 patients in the non-cerclage group and 34 patients in the cerclage group). The baseline data of the 2 groups were comparable. There were no significant difference in the length of hospital stay (z = -0.391, p = 0.696), operative time (z = -1.289, p = 0.197), or intraoperative blood loss (z = -1.321, p = 0.186). However, compared with non-cerclage group, the fracture union time was shorter (z = -5.587, p < 0.001), the rate of nonunion was lower (χ2 = 6.030, p = 0.03), the anatomical reduction rate was higher (χ2 = 5.449, p = 0.03), and the Harris hip score was higher (z = -2.99, p = 0.003) in the cerclage group, all with statistically significant differences. CONCLUSIONS: Intramedullary nailing combined with cable cerclage wiring is a safe and reliable technique for the treatment of irreducible subtrochanteric fractures. This technique can improve the reduction effect, increase the stability of fracture fixation, shorten the fracture union time, reduce the occurrence of nonunion, and contribute to the recovery of hip joint function.
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Telomere dynamics are linked to aging hallmarks, and age-associated telomere loss fuels the development of epithelial cancers. In Apc-mutant mice, the onset of DNA damage associated with telomere dysfunction has been shown to accelerate adenoma initiation via unknown mechanisms. Here, we observed that Apc-mutant mice engineered to experience telomere dysfunction show accelerated adenoma formation resulting from augmented cell competition and clonal expansion. Mechanistically, telomere dysfunction induces the repression of EZH2, resulting in the derepression of Wnt antagonists, which causes the differentiation of adjacent stem cells and a relative growth advantage to Apc-deficient telomere dysfunctional cells. Correspondingly, in this mouse model, GSK3ß inhibition countered the actions of Wnt antagonists on intestinal stem cells, resulting in impaired adenoma formation of telomere dysfunctional Apc-mutant cells. Thus, telomere dysfunction contributes to cancer initiation through altered stem cell dynamics, identifying an interception strategy for human APC-mutant cancers with shortened telomeres.
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Proteína de la Poliposis Adenomatosa del Colon , Células Madre , Telómero , Animales , Ratones , Telómero/metabolismo , Proteína de la Poliposis Adenomatosa del Colon/genética , Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Células Madre/metabolismo , Células Madre/patología , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Proteína Potenciadora del Homólogo Zeste 2/genética , Adenoma/patología , Adenoma/genética , Adenoma/metabolismo , Intestinos/patología , Diferenciación Celular , Humanos , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Glucógeno Sintasa Quinasa 3 beta/genética , Daño del ADN , Ratones Endogámicos C57BL , Vía de Señalización WntRESUMEN
Abundant macrophage infiltration and altered tumor metabolism are two key hallmarks of glioblastoma. By screening a cluster of metabolic small-molecule compounds, we show that inhibiting glioblastoma cell glycolysis impairs macrophage migration and lactate dehydrogenase inhibitor stiripentol emerges as the top hit. Combined profiling and functional studies demonstrate that lactate dehydrogenase A (LDHA)-directed extracellular signal-regulated kinase (ERK) pathway activates yes-associated protein 1 (YAP1)/ signal transducer and activator of transcription 3 (STAT3) transcriptional co-activators in glioblastoma cells to upregulate C-C motif chemokine ligand 2 (CCL2) and CCL7, which recruit macrophages into the tumor microenvironment. Reciprocally, infiltrating macrophages produce LDHA-containing extracellular vesicles to promote glioblastoma cell glycolysis, proliferation, and survival. Genetic and pharmacological inhibition of LDHA-mediated tumor-macrophage symbiosis markedly suppresses tumor progression and macrophage infiltration in glioblastoma mouse models. Analysis of tumor and plasma samples of glioblastoma patients confirms that LDHA and its downstream signals are potential biomarkers correlating positively with macrophage density. Thus, LDHA-mediated tumor-macrophage symbiosis provides therapeutic targets for glioblastoma.
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Glioblastoma , Animales , Humanos , Ratones , Glioblastoma/genética , L-Lactato Deshidrogenasa/genética , Lactato Deshidrogenasa 5 , Ácido Láctico , Simbiosis , Microambiente TumoralRESUMEN
Ferroptosis is a type of cell death characterized by iron-dependent phospholipid peroxidation and reactive oxygen species overproduction. Ferroptosis induces immunogenic cell death and elicits anti-tumor immune responses, playing an important role in cancer immunotherapy. Ferroptosis suppression in cancer cells impairs its immunotherapeutic efficacy. To overcome this issue, ferroptosis inducers (FINs) have been combined with other cancer therapies to create an anti-tumor immune microenvironment. However, the ferroptosis-based crosstalk between immune and tumor cells is complex because oxidative products released by ferroptotic tumor cells impair the functions of anti-tumor immune cells, resulting in immunotherapeutic resistance. In the present article, we have reviewed ferroptosis in tumor and immune cells and summarized the crosstalk between ferroptotic tumor cells and the immune microenvironment. Based on the existing literature, we have further discussed future perspectives on opportunities for combining ferroptosis-targeted therapies with cancer immunotherapies.
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Ferroptosis , Neoplasias , Humanos , Inmunoterapia , Neoplasias/terapia , Especies Reactivas de Oxígeno , Microambiente TumoralRESUMEN
BACKGROUND: Neoadjuvant chemotherapy (neoCTX) has been recommended as the optimal strategy in surgically resectable neuroendocrine carcinoma (NEC) of the urinary tract (NEC-URO). OBJECTIVE: To determine the systemic therapy regimen and timing, which are most active against NEC-URO. DESIGN, SETTING, AND PARTICIPANTS: We used our institutional historical clinical and pathological database to study 203 patients (cT2, 74%; cT3/4a, 22%; and cTx, 4%) with surgically resectable NEC-URO between November 1985 and May 2020. A total of 141 patients received neoCTX and 62 underwent initial radical surgery, 24 of whom received adjuvant CTX (adjCTX). INTERVENTION: Neoadjuvant CTX with etoposide/cisplatin (EP), an alternating doublet of ifosfamide/doxorubicin (IA) and EP, dose-dense methotrexate/vinblastine/doxorubicin/cisplatin (MVAC), gemcitabine/cisplatin (GC), or others. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Overall survival (OS), downstaging rate, and pathological complete response using a multivariable model adjusting for tumor- and patient-related factors. RESULTS AND LIMITATIONS: Downstaging rate was significantly improved with neoCTX versus initial surgery (49.6% vs 14.5%, pâ¯<â¯0.0001), stage cT2N0 versus cT3/4N0 (44% vs 25%, pâ¯=â¯0.01), or presence of carcinoma in situ (47% vs 28%, pâ¯=â¯0.01). Downstaging was greatest with IA/EP (65%) versus EP (39%), MVAC/GC (27%), or others (36%, pâ¯=â¯0.04). After adjusting for age and Eastern Cooperative Oncology Group performance status, IA/EP was still associated with improved downstaging (odds ratioâ¯=â¯3.7 [1.3-10.2], pâ¯=â¯0.01). At a median follow-up of 59.7 mo, 5-yr OS rates for neoCTX followed by surgery, surgery alone, and surgery followed by adjCTX were 57%, 22%, and 30%, respectively. An NEC regimen (IA/EP or EP) versus a urothelial regimen (MVAC/GC or others) was associated with improved survival (145.4 vs 42.5 mo, hazard ratioâ¯=â¯0.49, 95% confidence interval: 0.25-0.94). CONCLUSIONS: Neoadjuvant CTX remains the standard-of-care treatment for NEC-URO with an advantage for NEC regimens over traditional urothelial regimens. IA/EP improves pathological downstaging at the time of surgery compared with EP, but is reserved for younger and higher function patients. PATIENT SUMMARY: In this report, we looked at the outcomes from invasive neuroendocrine carcinoma of the urinary tract in a large US population. We found that the outcomes varied with treatment strategy. We conclude that the best outcomes are seen in patients treated with chemotherapy prior to surgery and regimens tailored to histology and tolerance.
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Carcinoma Neuroendocrino , Neoplasias de la Vejiga Urinaria , Sistema Urinario , Humanos , Neoplasias de la Vejiga Urinaria/patología , Cisplatino/uso terapéutico , Gemcitabina , Desoxicitidina/uso terapéutico , Sistema Urinario/patología , Carcinoma Neuroendocrino/tratamiento farmacológico , Carcinoma Neuroendocrino/cirugíaRESUMEN
Peroxisome proliferator-activated receptors (PPARs) are transcription factors belonging to the nuclear receptor family. There are three subtypes of PPARs, including PPAR-α, PPAR-ß/δ and PPAR-γ. They are expressed in different tissues and act by regulating the expression of target genes in the form of binding to ligands. Various subtypes of PPAR have been shown to have significant roles in a wide range of biological processes including lipid metabolism, body energy homeostasis, cell proliferation and differentiation, bone formation, tissue repair and remodelling. Recent studies have found that PPARs are closely related to tumours. They are involved in cancer cell growth, angiogenesis and tumour immune response, and are essential components in tumour progression and metastasis. As such, they have become a target for cancer therapy research. In this review, we discussed the current state of knowledge on the involvement of PPARs in cancer, including their role in tumourigenesis, the impact of PPARs in tumour microenvironment and the potential of using PPARs combinational therapy to treat cancer by targeting essential signal pathways, or as adjuvants to boost the effects of current chemo and immunotherapies. Our review highlights the complexity of PPARs in cancer and the need for a better understanding of the mechanism in order to design effective cancer therapies.
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Oncogenic KRAS (KRAS*) contributes to many cancer hallmarks. In colorectal cancer, KRAS* suppresses antitumor immunity to promote tumor invasion and metastasis. Here, we uncovered that KRAS* transforms the phenotype of carcinoma-associated fibroblasts (CAF) into lipid-laden CAFs, promoting angiogenesis and tumor progression. Mechanistically, KRAS* activates the transcription factor CP2 (TFCP2) that upregulates the expression of the proadipogenic factors BMP4 and WNT5B, triggering the transformation of CAFs into lipid-rich CAFs. These lipid-rich CAFs, in turn, produce VEGFA to spur angiogenesis. In KRAS*-driven colorectal cancer mouse models, genetic or pharmacologic neutralization of TFCP2 reduced lipid-rich CAFs, lessened tumor angiogenesis, and improved overall survival. Correspondingly, in human colorectal cancer, lipid-rich CAF and TFCP2 signatures correlate with worse prognosis. This work unveils a new role for KRAS* in transforming CAFs, driving tumor angiogenesis and disease progression, providing an actionable therapeutic intervention for KRAS*-driven colorectal cancer. SIGNIFICANCE: This study identified a molecular mechanism contributing to KRAS*-driven colorectal cancer progression via fibroblast transformation in the tumor microenvironment to produce VEGFA driving tumor angiogenesis. In preclinical models, targeting the KRAS*-TFCP2-VEGFA axis impaired tumor progression, revealing a potential novel therapeutic option for patients with KRAS*-driven colorectal cancer. This article is featured in Selected Articles from This Issue, p. 2489.
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Fibroblastos Asociados al Cáncer , Neoplasias del Colon , Proteínas Proto-Oncogénicas p21(ras) , Animales , Humanos , Ratones , Angiogénesis , Fibroblastos Asociados al Cáncer/metabolismo , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Neoplasias Colorrectales/metabolismo , Proteínas de Unión al ADN/metabolismo , Fibroblastos/metabolismo , Lípidos , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Factores de Transcripción/metabolismo , Microambiente Tumoral/genéticaRESUMEN
BACKGROUND: Although the role of adjuvant chemotherapy (CT) for resectable biliary tract cancer (BTC) is gradually recognized, the benefit of adjuvant chemoradiotherapy (CRT) is still controversial. Our study is designed to compare the prognosis of CRT versus CT in BCT patients. METHODS: Clinicopathologic characteristics of patients with operable gallbladder cancer (GBCA), intrahepatic bile duct cancer (IHBDC), or extrahepatic bile duct cancer (EHBDC) were obtained from the Surveillance, Epidemiology and End Results (SEER) database (2004-2015). Univariate and multivariate analyses were performed to identify prognostic factors for overall survival (OS). Selection bias were reduced by propensity-score matching (PSM). Kaplan-Meier analysis was used to estimate the survival time. RESULTS: Within 922 patients, 53.9% received adjuvant CRT, and 46.1% received adjuvant CT. Multivariate analysis showed age, primary tumor site, T stage, N stage, tumor size, number of removed lymph nodes, and treatment were independent risk factors for OS. Similar improvement of CRT on survival was identified by PSM in the matched cohort compared with CT (28.0 months vs. 25.0 months, p = 0.033), particularly in GBCA cohort (25.0 months vs. 19.0 months, p = 0.003). Subgroup analysis indicated CRT improved outcomes of patients with age ≥ 60, female, lymph nodes positive, tumor size ≥ 5 cm, and none removed lymph node diseases. CONCLUSION: Adjuvant CRT correlated with improved survival in patients with resected BTC compared with adjuvant CT, particularly in GBCAs. In addition, patients with age ≥ 60, female, lymph nodes positive, tumor size ≥ 5 cm, and none removed lymph node diseases may receive more benefits from adjuvant CRT.
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Neoplasias de los Conductos Biliares , Neoplasias del Sistema Biliar , Neoplasias de la Vesícula Biliar , Humanos , Femenino , Quimioradioterapia Adyuvante , Puntaje de PropensiónRESUMEN
Poly(polyol sebacate) (PPS) polymer family has been recognized as promising biomaterials for biomedical applications with their characteristics of easy production, elasticity, biodegradation, and cytocompatibility. Poly(xylitol sebacate)-co-poly(ethylene glycol) (PXS-co-PEG) has been developed to fabricate PPS-based hydrogels; however, current PXS-co-PEG hydrogels presented limited properties and functions due to the limitations of the crosslinkers and crosslinking chemistry used in the hydrogel formation. Here, we fabricate a new type of PXS-co-PEG hydrogels through the use of multifunctional crosslinkers as well as dynamic bonds. In our design, polyethyleneimine-polydopamine (PEI-PDA) macromers are utilized to crosslink aldehyde-functionalized PXS-co-PEG (APP) through imine bonds and hydrogen bonds. PEI-PDA/APP hydrogels present multiple functional properties (e.g., fluorescent, elastomeric, biodegradable, self-healing, bioadhesive, antioxidant, and antibacterial behaviors). These properties of PEI-PDA/APP hydrogels can be fine-tuned by changing the PDA grafting degrees in the PEI-PDA crosslinkers. Most importantly, PEI-PDA/APP hydrogels are considered promising wound dressings to promote tissue remodeling and prevent bacterial infection in vivo. Taken together, PEI-PDA/APP hydrogels have been demonstrated as versatile biomaterials to provide multiple tailorable properties and desirable functions to expand the utility of PPS-based hydrogels for advanced biomedical applications. STATEMENT OF SIGNIFICANCE: Various strategies have been developed to fabricate poly(polyol sebacate) (PPS)-based hydrogels. However, current PPS-based hydrogels present limited properties and functions due to the limitations of the crosslinkers and crosslinking chemistry used in the hydrogel formation. This work describes that co-engineering crosslinkers and interfacial crosslinking is a promising approach to synthesizing a new type of poly(xylitol sebacate)-co-poly(ethylene glycol) (PXS-co-PEG) hydrogels as multifunctional hydrogels to expand the utility of PPS-based hydrogels for advanced biomedical applications. The fabricated hydrogels present multiple functional properties (e.g., fluorescent, biodegradable, elastomeric, self-healing, bioadhesive, antioxidative, and antibacterial), and these properties can be fine-tuned by the defined crosslinkers. The fabricated hydrogels are also used as promising wound dressing biomaterials to exhibit promoted tissue remodeling and prevent bacterial infection in vivo.
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Infecciones Bacterianas , Xilitol , Humanos , Polietilenglicoles/química , Materiales Biocompatibles/farmacología , Materiales Biocompatibles/química , Antioxidantes/farmacología , Cicatrización de Heridas , Hidrogeles/farmacología , Hidrogeles/química , Polietileneimina , AntibacterianosRESUMEN
Cancer is a disease with ecological and evolutionary unity, which seriously affects the survival and quality of human beings. Currently, many reports have suggested Gas6 plays an important role in cancer. Binding of gas6 to TAM receptors is associated with the carcinogenetic mechanisms of multiple malignancies, such as in breast cancer, chronic lymphocytic leukemia, non-small cell lung cancer, melanoma, prostate cancer, etc., and shortened overall survival. It is accepted that the Gas6/TAM pathway can promote the malignant transformation of various types of cancer cells. Gas6 has the highest affinity for Axl, an important member of the TAM receptor family. Knockdown of the TAM receptors Axl significantly affects cell cycle progression in tumor cells. Interestingly, Gas6 also has an essential function in the tumor microenvironment. The Gas6/AXL pathway regulates angiogenesis, immune-related molecular markers and the secretion of certain cytokines in the tumor microenvironment, and also modulates the functions of a variety of immune cells. In addition, evidence suggests that the Gas6/AXL pathway is involved in tumor therapy resistance. Recently, multiple studies have begun to explore in depth the importance of the Gas6/AXL pathway as a potential tumor therapeutic target as well as its broad promise in immunotherapy; therefore, a timely review of the characteristics of the Gas6/AXL pathway and its value in tumor treatment strategies is warranted. This comprehensive review assessed the roles of Gas6 and AXL receptors and their associated pathways in carcinogenesis and cancer progression, summarized the impact of Gas6/AXL on the tumor microenvironment, and highlighted the recent research progress on the relationship between Gas6/AXL and cancer drug resistance.
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Nanocomposite (NC) hydrogels used for sonodynamic therapy (SDT) face challenges such as lacking interfacial interactions between the polymers and nanomaterials as well as presenting uneven dispersion of nanomaterials in the hydrogel network, reducing their mechanical properties and treatment efficiency. Here, we demonstrate a promising approach of co-engineering nanomaterials and interfacial crosslinking to expand the materials construction and biomedical applications of NC hydrogels in SDT. In this work, mesoporous silica-coated titanium dioxide nanoparticles with thiolated surface functionalization (TiO2@MS-SH) are utilized as crosslinkers to react with norbornene-functionalized dextran (Nor-Dex) through ultrasound-triggered thiol-norbornene reactions, forming TiO2@MS-SH/Nor-Dex NC hydrogels. The TiO2@MS-SH nanoparticles act not only as multivalent crosslinkers to improve the mechanical properties of hydrogels under ultrasound irradiation but also as reactive oxygen species (ROS) generators to allow the use of TiO2@MS-SH/Nor-Dex NC hydrogels in SDT applications. Particularly, the TiO2@MS-SH/Nor-Dex NC hydrogels present tailorable microstructures, properties, and sonodynamic killing of bacteria through the modulation of the ultrasound frequency. Taken together, a versatile TiO2-based NC hydrogel platform prepared under ultrasonic interfacial crosslinking reactions is developed for advancing the applications in SDT.
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Compuestos de Sulfhidrilo , Ultrasonido , Nanogeles , Compuestos de Sulfhidrilo/química , Hidrogeles/farmacología , Hidrogeles/química , Norbornanos/químicaRESUMEN
Force and torque spectroscopy have provided unprecedented insights into the mechanical properties, conformational transitions, and dynamics of DNA and DNA-protein complexes, notably nucleosomes. Reliable single-molecule manipulation measurements require, however, specific and stable attachment chemistries to tether the molecules of interest. Here, we present a functionalization strategy for DNA that enables high-yield production of constructs for torsionally constrained and very stable attachment. The method is based on two subsequent PCRs: first â¼380 bp long DNA strands are generated that contain multiple labels, which are used as "megaprimers" in a second PCR to generate â¼kbp long double-stranded DNA constructs with multiple labels at the respective ends. To achieve high-force stability, we use dibenzocyclooctyne-based click chemistry for covalent attachment to the surface and biotin-streptavidin coupling to the bead. The resulting tethers are torsionally constrained and extremely stable under load, with an average lifetime of 70 ± 3 h at 45 pN. The high yield of the approach enables nucleosome reconstitution by salt dialysis on the functionalized DNA, and we demonstrate proof-of-concept measurements on nucleosome assembly statistics and inner turn unwrapping under force. We anticipate that our approach will facilitate a range of studies of DNA interactions and nucleoprotein complexes under forces and torques.
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ADN , Nucleosomas , ADN/química , Fenómenos Mecánicos , Fenómenos Biofísicos , Reacción en Cadena de la PolimerasaRESUMEN
Background: Although anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) have impressive response in advanced lung adenocarcinoma with anaplastic lymphoma kinase (ALK) fusion, no guidelines point to the potential benefits of neoadjuvant ALK-TKIs for N3 unresectable locally advanced lung cancer. Current ongoing clinical trials mainly focus on the efficacy of neoadjuvant ALK-TKIs in resectable locally advanced lung cancer and ignore the role of neoadjuvant ALK-TKIs in N3 unresectable locally advanced lung cancer. Materials and methods: We report a lung cancer case with a novel INTS10-ALK and EML4-ALK rearrangement that achieved complete pathologic response to neoadjuvant crizotinib. We conducted molecular pathologic analysis by using next-generation sequencing (NGS). Genomic DNA was extracted from formalin-fixed paraffin-embedded (FFPE) samples and profiled using a capture-based targeted sequencing panel consisting of 56 lung cancer-related genes. Results: Our study reported a patient with stage IIIB-N3 lung adenocarcinoma with an unreported dual ALK rearrangement (INTS10-ALK and EML4-ALK) who received 5 months of crizotinib, followed by R0 right upper lobectomy, achieving complete pathological response (ypT0 ypN0). No recurrence of the tumor was found for 3 years postoperatively. Conclusion: The case supports the strategy of neoadjuvant ALK inhibitors for N3 unresectable locally advanced lung cancer, expanding the spectrum of treatment of stage IIIB-N3 lung cancer.
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Glioblastoma (GBM) is one of the most aggressive tumors in the adult central nervous system. We previously revealed that circadian regulation of glioma stem cells (GSCs) affects GBM hallmarks of immunosuppression and GSC maintenance in a paracrine and autocrine manner. Here, we expand the mechanism involved in angiogenesis, another critical GBM hallmark, as a potential basis underlying CLOCK's pro-tumor effect in GBM. Mechanistically, CLOCK-directed olfactomedin like 3 (OLFML3) expression results in hypoxia-inducible factor 1-alpha (HIF1α)-mediated transcriptional upregulation of periostin (POSTN). As a result, secreted POSTN promotes tumor angiogenesis via activation of the TANK-binding kinase 1 (TBK1) signaling in endothelial cells. In GBM mouse and patient-derived xenograft models, blockade of the CLOCK-directed POSTN-TBK1 axis inhibits tumor progression and angiogenesis. Thus, the CLOCK-POSTN-TBK1 circuit coordinates a key tumor-endothelial cell interaction and represents an actionable therapeutic target for GBM.
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Neoplasias Encefálicas , Relojes Circadianos , Glioblastoma , Glioma , Animales , Humanos , Ratones , Neoplasias Encefálicas/metabolismo , Línea Celular Tumoral , Relojes Circadianos/genética , Modelos Animales de Enfermedad , Células Endoteliales/metabolismo , Glioblastoma/patología , Glioma/patología , Glicoproteínas/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Células Madre Neoplásicas/metabolismoRESUMEN
Deficiency of MTAP (MTAPdef) mainly occurs because of homozygous loss of chromosome 9p21, which is the most common copy-number loss in metastatic urothelial cancer (mUC). We characterized the clinical and genomic features of MTAPdef mUC in 193 patients treated at MD Anderson Cancer Center (MDACC) and 298 patients from the phase 2 IMvigor210 trial, which investigated atezolizumab in cisplatin-ineligible and platinum-refractory disease. In the MDACC cohort, visceral metastases were significantly more common for MTAPdef (n = 48) than for MTAP-proficient (MTAPprof; n = 145) patients (75% vs 55.2%; p = 0.02). MTAPdef was associated with poor prognosis (median overall survival [mOS] 12.3 vs 20.2 mo; p = 0.007) with an adjusted hazard ratio of 1.93 (95% confidence interval 1.35-2.98). Similarly, IMvigor210 patients with MTAPlo (n = 29) had a higher incidence of visceral metastases than those with MTAPhi tumors (n = 269; 86.2% vs 72.5%; p = 0.021) and worse prognosis (mOS 8.0 vs 11.3 mo; p = 0.042). Hyperplasia-associated genes were more frequently mutated in MTAPdef tumors (FGFR3: 31% vs 8%; PI3KCA: 31% vs 19%), while alterations in dysplasia-associated genes were less common in MTAPdef tumors (TP53: 41% vs 67%; RB1: 0% vs 16%). Our findings support a distinct biology in MTAPdef mUC that is associated with early visceral disease and worse prognosis. PATIENT SUMMARY: We investigated the outcomes for patients with the most common gene loss (MTAP gene) in metastatic cancer of the urinary tract. We found that this loss correlates with worse prognosis and a higher risk of metastasis in internal organs. There seems to be distinct tumor biology for urinary tract cancer with MTAP gene loss and this could be a potential target for treatment.
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Carcinoma de Células Transicionales , Humanos , Pronóstico , Carcinoma de Células Transicionales/tratamiento farmacológico , Genómica , Cisplatino/uso terapéutico , Modelos de Riesgos ProporcionalesRESUMEN
The structure and properties of DNA depend on the environment, in particular the ion atmosphere. Here, we investigate how DNA twist -one of the central properties of DNA- changes with concentration and identity of the surrounding ions. To resolve how cations influence the twist, we combine single-molecule magnetic tweezer experiments and extensive all-atom molecular dynamics simulations. Two interconnected trends are observed for monovalent alkali and divalent alkaline earth cations. First, DNA twist increases monotonously with increasing concentration for all ions investigated. Second, for a given salt concentration, DNA twist strongly depends on cation identity. At 100 mM concentration, DNA twist increases as Na+ < K+ < Rb+ < Ba2+ < Li+ ≈ Cs+ < Sr2+ < Mg2+ < Ca2+. Our molecular dynamics simulations reveal that preferential binding of the cations to the DNA backbone or the nucleobases has opposing effects on DNA twist and provides the microscopic explanation of the observed ion specificity. However, the simulations also reveal shortcomings of existing force field parameters for Cs+ and Sr2+. The comprehensive view gained from our combined approach provides a foundation for understanding and predicting cation-induced structural changes both in nature and in DNA nanotechnology.
Asunto(s)
ADN , Simulación de Dinámica Molecular , Cationes , Cationes Bivalentes , Cationes Monovalentes , ADN/química , Sodio , Cloruro de SodioRESUMEN
Developmental petal senescence is a type of programmed cell death (PCD), during which the production of ethylene is induced, the expression of PCD-related genes is upregulated, and nutrients are recycled. Autophagy is an intracellular mechanism involved in PCD modulation and nutrient cycling. As a central component of the autophagy pathway, Autophagy Gene 6 (ATG6) was previously shown as a negative regulator of petal senescence. To better understand the role of autophagy in ethylene biosynthesis and nutrient remobilization during petal senescence, we generated and characterized the knockout (KO) mutants of PhATG6 using CRISPR/Cas9 in Petunia × hybrida 'Mitchell Diploid.' PhATG6-KO lines exhibited decreased flower longevity when compared to the flowers of the wild-type or a non-mutated regenerative line (controls), confirming the negative regulatory role of ATG6 in petal senescence. Smaller capsules and fewer seeds per capsule were produced in the KO plants, indicating the crucial function of autophagy in seed production. Ethylene production and ethylene biosynthesis genes were upregulated earlier in the KO lines than the controls, indicating that autophagy affects flower longevity through ethylene. The transcript levels of petal PCD-related genes, including PhATG6, PhATG8d, PhPI3K (Phosphatidylinositol 3-Kinase), and a metacaspase gene PhMC1, were upregulated earlier in the corollas of PhATG6-KO lines, which supported the accelerated PCD in the KO plants. The remobilization of phosphorus was reduced in the KO lines, showing that nutrient recycling was compromised. Our study demonstrated the important role of autophagy in flower lifespan and seed production and supported the interactions between autophagy and various regulatory factors during developmental petal senescence.