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Liver metastasis is a major cause of morbidity and mortality in patients with colorectal cancer. A better understanding of the biological mechanisms underlying liver tropism and metastasis in colorectal cancer could help to identify improved prevention and treatment strategies. In this study, we performed genome-side CRISPR loss-of-function screening in a mouse colorectal cancer model and identified deficiency of AFDN, a protein involved in establishing and maintaining cell-cell contacts, as a driver of liver metastasis. Elevated AFDN expression was correlated with prolonged survival in patients with colorectal cancer. AFDN-deficient colorectal cancer cells preferentially metastasized to the liver but not in the lungs. AFDN loss in colorectal cancer cells at the primary site promoted cancer cell migration and invasion by disrupting tight intercellular junctions. Additionally, CXCR4 expression was increased in AFDN-deficient colorectal cancer cells via the JAK-STAT signaling pathway, which reduced the motility of AFDN-deficient colorectal cancer cells and facilitated their colonization of the liver. Collectively, these data shed light on the mechanism by which AFDN deficiency promotes liver tropism in metastatic colorectal cancer.
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Establishing homojunctions at the molecular level between different but physicochemically similar phases belonging to the same family of materials is an effective approach to promoting the photocatalytic activity of polymeric carbon nitride (CN) materials. Here, we prepared a CN material with a uniform distribution of homojunctions by combining two synthetic strategies: supramolecular assemblies as the precursor and molten salt as the medium. We designed porous CN rods with triazine-heptazine homojunctions (THCNs) using a melem supramolecular aggregate (Me) and melamine as the precursors and a KCl/LiBr salt mixture as the liquid reaction medium. The triazine/heptazine ratio is controlled by varying the relative amounts of the chosen precursors, and the molten salt treatment enhances the structural order of the interplanar packing units for the THCN skeleton, leading to rapid charge migration. The resulting built-in electric field induced by the triazine-heptazine homojunction enhances photogenerated charge separation; the optimal THCN catalyst exhibits an excellent H2 evolution rate via photocatalytic water splitting, which is â¼24 times as high as that of reference bulk CN, with long-term stability.
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Our previous study demonstrated that tumor-suppressor circular RNAs (circRNAs) can be specifically secreted outside of colorectal cancer (CRC) cells within exosomes to maintain tumor cell fitness. However, whether tumor-driving circRNAs can be specifically retained in cells to facilitate tumor progression remains unknown. In this study, circRNA-seq showed that circSKA3 was significantly upregulated in CRC tissues but downregulated in serum samples from CRC patients. In addition, circSKA3 promoted CRC progression in vitro and in vivo and was retained in CRC cells via a specific cellmotif element. Interestingly, the cellmotif element was also the site of interaction of circSKA3 with SLUG, which inhibited SLUG ubiquitination degradation and promoted CRC epithelial-mesenchymal transition (EMT). Moreover, FUS was identified as a key circularization regulator of circSKA3 that bound to the key element. Finally, we designed and synthesized specific antisense oligonucleotides (ASOs) targeting circularization and cellmotif elements, which repressed circSKA3 expression, abolished the SLUG-circSKA3 interaction, and further inhibited CRC EMT and metastasis in vitro and in vivo.
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Neoplasias Colorrectales , ARN Circular , Humanos , Neoplasias Colorrectales/patología , Genes Supresores de Tumor , ARN Circular/genética , ARN Circular/metabolismo , UbiquitinaciónRESUMEN
The crosstalk between ferroptosis and cancer metastasis remains unclear. Here, we identify AMER1 as a key regulator of ferroptosis. AMER1 loss causes resistance to ferroptosis in colorectal cancer (CRC) cells. Interestingly, AMER1-deficient CRC cells preferentially form distant metastases, while AMER1-naive CRC cells mainly invade lymph nodes. Moreover, the ferroptosis inhibitor liproxstatin-1 effectively promotes hematogenous transfer of AMER1-naive cells. Mechanistically, AMER1 binds to SLC7A11 and ferritin light chain (FTL) and recruits ß-TrCP1/2, which degrade SLC7A11 and FTL by ubiquitination. Therefore, AMER1 deficiency increases cellular cystine levels but decreases the pool of labile free iron, thereby enhancing resistance to ferroptosis in CRC cells. Thus, AMER1 deficiency increases the survival of CRC cells in the blood under conditions of high oxidative stress and then promotes hematogenous metastasis of CRC. In conclusion, AMER1 mediates the crosstalk between ferroptosis and cancer metastasis, which provides a window of opportunity for treating metastatic colorectal cancer patients with AMER1 mutations.
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Neoplasias del Colon , Neoplasias Colorrectales , Ferroptosis , Humanos , Apoferritinas , Reacciones Cruzadas , Cistina , Neoplasias Colorrectales/genética , Sistema de Transporte de Aminoácidos y+/genética , Proteínas Supresoras de Tumor , Proteínas Adaptadoras Transductoras de SeñalesRESUMEN
BACKGROUND: The proteome is a major source of therapeutic targets. We conducted a proteome-wide Mendelian randomization (MR) study to identify candidate protein markers and therapeutic targets for colorectal cancer (CRC). METHODS: Protein quantitative trait loci (pQTLs) were derived from seven published genome-wide association studies (GWASs) on plasma proteome, and summary-level data were extracted for 4853 circulating protein markers. Genetic associations with CRC were obtained from a large-scale GWAS meta-analysis (16,871 cases and 26,328 controls), the FinnGen cohort (4957 cases and 304,197 controls), and the UK Biobank (9276 cases and 477,069 controls). Colocalization and summary-data-based MR (SMR) analyses were performed sequentially to verify the causal role of candidate proteins. Single cell-type expression analysis, protein-protein interaction (PPI), and druggability evaluation were further conducted to detect the specific cell type with enrichment expression and prioritize potential therapeutic targets. RESULTS: Collectively, genetically predicted levels of 13 proteins were associated with CRC risk. Elevated levels of two proteins (GREM1, CHRDL2) and decreased levels of 11 proteins were associated with an increased risk of CRC, among which four (GREM1, CLSTN3, CSF2RA, CD86) were prioritized with the most convincing evidence. These protein-coding genes are mainly expressed in tissue stem cells, epithelial cells, and monocytes in colon tumor tissue. Two interactive pairs of proteins (GREM1 and CHRDL2; MMP2 and TIMP2) were identified to be involved in osteoclast differentiation and tumorigenesis pathways; four proteins (POLR2F, CSF2RA, CD86, MMP2) have been targeted for drug development on autoimmune diseases and other cancers, with the potentials of being repurposed as therapeutic targets for CRC. CONCLUSIONS: This study identified several protein biomarkers to be associated with CRC risk and provided new insights into the etiology and promising targets for the development of screening biomarkers and therapeutic drugs for CRC.
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Neoplasias Colorrectales , Proteoma , Humanos , Metaloproteinasa 2 de la Matriz , Estudio de Asociación del Genoma Completo , Biomarcadores , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Proteínas de Unión al Calcio , Proteínas de la Membrana , Proteínas de la Matriz ExtracelularRESUMEN
Precise and specific spatiotemporal domains of gene expression regulation are critical for embryonic development. Recent studies have identified GLTSCR1 as a gene transcriptional elongation regulator in cancer research. However, the function of GLTSCR1, especially in embryonic development, remains poorly understood. Here, we found that GLTSCR1 was essential for cardiac development because Gltscr1 knockout (Gltscr1-/-) led to embryonic lethality in mice with severe congenital heart defects (CHDs). Ventricular septal defect and double outflow right ventricular were also observed in neural crest cells with conditional deletion of Gltscr1, which were associated with neonatal lethality in mice. Mechanistically, GLTSCR1 deletion promoted NPPA expression by coordinating the CHD risk G allele of rs56153133 in the NPPA enhancer and releasing the transcription factor ZNF740-binding site on the NPPA promoter. These findings demonstrated that GLTSCR1 acts as a candidate CHD-related gene.
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Factor Natriurético Atrial , Proteínas Cromosómicas no Histona , Cardiopatías Congénitas , Proteínas Supresoras de Tumor , Animales , Femenino , Ratones , Embarazo , Proteínas Cromosómicas no Histona/metabolismo , Desarrollo Embrionario , Regulación de la Expresión Génica , Cardiopatías Congénitas/genética , Cardiopatías Congénitas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Factor Natriurético Atrial/genéticaRESUMEN
The glycolytic enzyme enolase 2 (ENO2) is dysregulated in many types of cancer. However, the roles and detailed molecular mechanism of ENO2 in colorectal cancer (CRC) metastasis remain unclear. Here, we performed a comprehensive analysis of ENO2 expression in 184 local CRC samples and samples from the TCGA and GEO databases and found that ENO2 upregulation in CRC samples was negatively associated with prognosis. By knocking down and overexpressing ENO2, we found that ENO2 promoted CRC cell migration and invasion, which is dependent on its interaction with the long noncoding RNA (lncRNA) CYTOR, but did not depend on glycolysis regulation. Furthermore, CYTOR mediated ENO2 binding to large tumor suppressor 1 (LATS1) and competitively inhibited the phosphorylation of Yes-associated protein 1 (YAP1), which ultimately triggered epithelial-mesenchymal transition (EMT). Collectively, these findings highlight the molecular mechanism of the ENO2-CYTOR interaction, and ENO2 could be considered a potential therapeutic target for CRC.
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Neoplasias Colorrectales , ARN Largo no Codificante , Línea Celular Tumoral , Neoplasias Colorrectales/patología , Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Procesos Neoplásicos , Fosfopiruvato Hidratasa/genética , Fosfopiruvato Hidratasa/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Proteínas Señalizadoras YAPRESUMEN
MIR4435-2HG, also known as LINC00978, has previously been described as an oncogenic long noncoding RNA (lncRNA). However, we show here that Mir4435-2hg depletion promoted colorectal tumorigenesis and progression in in vivo models of colitis-associated colorectal cancer, spontaneous intestinal adenomatous polyposis, and subcutaneous tumors. Alteration of MIR4435-2HG in colorectal cancer cells did not change the potential for cell proliferation, migration, or invasion in vitro. RNAscope assays showed that most MIR4435-2HG was located in the tumor stroma, which caused high expression of MIR4435-2HG in colorectal cancer tumor tissue. Transcriptome analysis of colorectal cancer tissues from wild-type and Mir4435-2hg-deficient mice revealed Mir4435-2hg as a tumor suppressor gene that regulated the immune microenvironment. Loss of Mir4435-2hg led to a decline in neutrophils and elevation of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC). In tissue-specific Mir4435-2hg knockout mice, we confirmed that Mir4435-2hg depletion in neutrophils, but not in intestinal epithelial cells, promoted colorectal cancer progression. Mechanistically, Mir4435-2hg depletion enhanced the immunosuppressive ability of PMN-MDSCs by disturbing their fatty acid metabolism. These findings suggest that MIR4435-2HG is a tumor-suppressing lncRNA whose deficiency could increase tumor-infiltrating PMN-MDSCs and enhance the immunosuppressive potential of PMN-MDSCs to promote colorectal cancer development. This provides a theoretical basis for further illustrating the pathogenesis of colorectal cancer and a potential antitumor immunotherapy target.
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Neoplasias Colorrectales , Células Supresoras de Origen Mieloide , ARN Largo no Codificante , Animales , Carcinogénesis/genética , Proliferación Celular/genética , Neoplasias Colorrectales/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Neutrófilos , ARN Largo no Codificante/genética , Microambiente TumoralRESUMEN
Cancer metastasis accounts for the majority of cancer motility burden. For colorectal cancer (CRC), the liver is the most common site of distant metastasis. It is still little known that cancer genomic mutations, which are a cell-intrinsic and heritable property, are enriched in CRC liver metastasis. Here, we try to answer the question in the context of polyclonal seeding. In this study, we sequenced 18 pairs of colorectal cancer primary tumors and their matched liver metastasis samples. Together with public available sequencing data, we compared the mutations in 113 primary and metastasis pairs. The TP53 mutation variant allele frequency (VAF) was significantly increased in metastasis compared to the paired primary tumor, although most of the frequently observed mutations in liver metastasis foci were concordant with their matched CRC primary tumors. The results support late metastasis and polyclonal seeding. Consequently, we quantitatively compared the intratumor heterogeneity (ITH) between primary and metastasis tumors, and with the help of in silico metastasis simulation, we inferred that more than 10 cells take part in the CRC liver metastasis.
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Neoplasias Colorrectales , Neoplasias Hepáticas , Proteína p53 Supresora de Tumor , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Frecuencia de los Genes , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/secundario , Mutación , Proteína p53 Supresora de Tumor/genéticaRESUMEN
Alternative splicing (AS) and transcription elongation are vital biological processes, and their dysregulation causes multiple diseases, including tumors. However, the coregulatory mechanism of AS and transcription elongation in tumors remains unclear. This study demonstrates a novel AS pattern of tight junction protein 1 (ZO1) regulated by the RNA polymerase II elongation rate in colorectal cancer (CRC). Glioma tumor suppressor candidate region gene 1 (GLTSCR1) decreases the transcription elongation rate of ZO1 to provide a time window for binding of the splicing factor HuR to the specific motif in intron 22 of ZO1 and spliceosome recognition of the weak 3' and 5' splice sites in exon 23 to promote exon 23 inclusion. Since exon 23 inclusion in ZO1 suppresses migration and invasion of CRC cells, our findings suggest a novel potential therapeutic target for CRC.
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Empalme Alternativo , Proteínas Cromosómicas no Histona , Neoplasias Colorrectales , Proteínas Supresoras de Tumor , Proteína de la Zonula Occludens-1 , Proteínas Cromosómicas no Histona/genética , Neoplasias Colorrectales/genética , Exones , Humanos , Intrones , Sitios de Empalme de ARN , Proteínas Supresoras de Tumor/genética , Proteína de la Zonula Occludens-1/genéticaRESUMEN
BACKGROUND & AIMS: To clarify the biological roles, circularization process and secretion pathway of circRHOBTB3 in colorectal cancer (CRC) progression. METHODS: We performed a comprehensive analysis of circRNA levels in serum exosomes from multiple types of cancer patients in public databases and verified the higher level of circRHOBTB3 in CRC sera versus healthy donors by RT-qPCR. Then, the function of circRHOBTB3 in CRC was investigated in vitro and in vivo. RNA-seq and RNA pull-down assays together with mass spectrometry identified the downstream signals and the binding proteins of circRHOBTB3. Finally, Antisense oligonucleotides (ASOs) were designed to target circularization and secretion elements of circRHOBTB3 for CRC therapy. RESULTS: circRHOBTB3 levels were increased in the sera but was downregulated in tissue samples in CRC, and the downregulation was associated with poor prognosis. Furthermore, circRHOBTB3 acts a tumor-suppressive circRNA by repressing metabolic pathways, intracellular ROS production in CRC. Several key elements were discovered to regulate circRHOBTB3 circularization and exosomal secretion. Moreover, SNF8 was identified that sorts circRHOBTB3 into exosomes. Interestingly, we found that CRC cells could actively secrete more circRHOBTB3 than normal cells. According to the sequence of regulatory elements for circularization and exosomal secretion, we designed and synthesized ASOs, which increased circRHOBTB3 expression and blocked circRHOBTB3 exosomal secretion. More importantly, ASOs could inhibit CRC growth and metastasis in vitro and in vivo. CONCLUSIONS: circRHOBTB3 plays a tumor-suppressive role in CRC and has to be excreted out of cells to sustain cancer cell fitness. ASOs targeting regulatory elements for circularization and exosomal secretion will become a novel antitumor strategy.
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Neoplasias Colorrectales , Exosomas , MicroARNs , Línea Celular Tumoral , Movimiento Celular , Neoplasias Colorrectales/patología , Exosomas/metabolismo , Humanos , MicroARNs/genética , ARN Circular/genéticaRESUMEN
Colorectal cancer (CRC) is one of the most common malignant tumors of digestive system, and its main cause of death is tumor metastasis. The occurrence of CRC is a polygenic and multi-step complex process involving genetic and epigenetic alterations. It has been demonstrated that ADAMTS14 (A disintegrin and metalloproteinase with thrombospondin motifs 14) was hypermethylated in esophageal cancer using whole-genome methylation microarray in our previous report. The present study revealed that ADAMTS14 was highly methylated accompanied with low expression in CRC. In addition, demethylation agent 5-Aza-dC could demethylate ADAMTS14 promoter region and reactivate ADAMTS14 expression effectively in vitro. Therefore, promoter hypermethylation was probably contributed to ADAMTS14 epigenetic silencing in CRC. Furthermore, ADAMTS14 protein expression was higher at invasive tumor front than at the tumor center or other areas of tumor. Kaplan-meier survival analysis indicated that the high ADAMTS14 expression was correlated with poor prognosis in CRC patients, suggesting the possibility that ADAMTS14 is a promising indicator in the evaluation of CRC prognosis.
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Proteínas ADAMTS/genética , Biomarcadores de Tumor/genética , Neoplasias Colorrectales/genética , Metilación de ADN/genética , Anciano , Neoplasias Colorrectales/patología , Supervivencia sin Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica/genética , Células HCT116 , Humanos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Pronóstico , Regiones Promotoras Genéticas/genéticaRESUMEN
Nucleocytoplasmic transport of proteins is disrupted and dysregulated in cancer cells. Nuclear pore complexes and cargo proteins are two main transportation regulators. However, the mechanism regulating nucleocytoplasmic transport in cancer remains elusive. Here, we identified a S100A2/KPNA2 cotransport complex that transports the tumor-associated transcription factor NFYA in colorectal cancer (CRC). Through the S100A2/KNPA2 complex, depending on its interaction with S100A2, NFYA is transported to the nucleus and inhibits the transcriptional activity of E-cadherin, which in turn promotes CRC metastasis. Targeting the S100A2/KPNA2 binding sites with the specific inhibitor delanzomib is a potential therapeutic approach for CRC.
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alfa Carioferinas , Transporte Activo de Núcleo CelularRESUMEN
BACKGROUND: Colorectal cancer (CRC) is a kind of malignant tumor of digestive system severely affecting human health. The occurrence of CRC is a polygenic and multi-step complex process involving genetic and epigenetic alterations. ADAM12 (a disintegrin and metalloproteases 12), is a gene that was commonly hypermethylated in esophageal cancer using whole-genome methylation microarray in our previous study. METHODS: We detected the methylation frequencies of the CpG island in ADAM12 promoter using bisulfite-pyrosequencing in CRC cell lines and tissue samples. The expression of ADAM12 was detected by quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC). A systematic and comprehensive analysis of relationship of DNA hypermethylation and ADAM12 expression in CRC was performed in our samples and TCGA database. RESULTS: The expression of ADAM12 in hypermethylated cell lines was significantly lower than that in hypomethylated cell lines, and demethylation agent 5-Aza-dC could demethylate ADAM12 promoter region and reactivate ADAM12 expression effectively. In 74 pairs of colorectal cancer and normal tissues, bisulfite-pyrosequencing results showed significantly hypermethylation of ADAM12 in CRC compared with adjacent normal mucosa, accompanied with lower expression of ADAM12 in CRC tissues compared to that of the normal tissues. In addition, there was a statistically significant negative correlation between ADAM12 protein expression and methylation levels (rho =-0.28, pâ¯=â¯0.015). CONCLUSION: Promoter hypermethylation was probably a mechanism of ADAM12 epigenetic silencing in CRC.
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Proteína ADAM12/genética , Neoplasias Colorrectales/patología , Metilación de ADN/genética , Regulación Neoplásica de la Expresión Génica/genética , Regiones Promotoras Genéticas/genética , Proteína ADAM12/metabolismo , Adulto , Anciano , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
PURPOSE: Human papillomavirus (HPV) infection has been recognized as a cause of head and neck squamous cell carcinomas (HNSCC). Laryngeal squamous cell carcinoma (LSCC) is one of the most common pathologic types of HNSCC. Clinical trials show that there are differences in response to immunotherapy according to HPV status. It was reported that a high level of programmed cell death-ligand 1 (PD-L1) is correlated with better survival in HPV-positive head and neck cancer. In this study, we investigated the expression of PD-L1 in HPV-positive and HPV-negative LSCC to determine its prevalence and prognostic value. METHODS: 52 cases of LSCC were collected from Tangshan Head and Neck Disease Pathology Research Base. PCR-reverse dot blot hybridization and RNAscope in situ hybridization were used to detect HPV status. PD-L1 expression was evaluated by immunohistochemistry and all cases were followed up for survival. SPSS24.0 was used for data entry and statistical analysis. Kaplan-Meier method and Log-rank time series analysis were used for single factor analysis. Multivariate analysis was performed using Cox proportional hazard regression model, and HR and 95% CI were calculated. RESULTS: Of the 52 LSCC patients, 32.7% (17/52) were HPV-positive by RNAscope in situ hybridization, and 51.9% (27/52) of patients were positive for PD-L1 expression by immunohistochemistry. Regression analysis showed that with a median follow-up period of 69 months, smoking and late stage were associated with poor overall survival (OS), whereas HPV positivity and PD-L1 expression showed a better overall survival outcome. CONCLUSION: Smoking status, tumor stage, HPV status, and PD-L1 expression in tumor cells may represent useful prognostic biomarkers in patients with LSCC.
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High risk human papillomavirus (HPV) infection is related to the development of head and neck squamous cell carcinoma (HNSCC). Oropharyngeal squamous cell carcinoma (OPSCC) is a common type of HNSCC, and its incidence has increased significantly in recent years. In this study, high risk HPV, the expression of P53, P21, and Cdc2 in OPSCC tissues was detected and the prognostic factors and clinical value of OPSCC were discussed. According to the WHO classification and diagnosis standard for head and neck tumors (2017 Edition), 49 OPSCC cases with complete clinical data were collected from Tangshan Head and Neck Disease Pathology Research Base from January 1, 2012 to December 31, 2018. The E6 and E7 mRNA of HPV 16 and HPV 18 were detected by RNAscope in situ hybridization. The expression of P53, P21, and Cdc2 protein was observed by SP immunohistochemical method and all cases were followed up for survival. Median survival time was analyzed by Kaplan-Meier method. The Log-rank test was used for single factor analysis and Cox regression model was used to analyze multiple prognostic factors. In 49 OPSCC cases the median age was 53 years; 14 were HPV-DNA positive (14/49, 28.6%) while 35 were negative (35/49, 71.4%). E6, E7 mRNA test showed that 20 cases (20/49, 40.8%) were positive for HPV-16. Among them 11 cases were positive for HPV-16 DNA. 2 cases were positive for HPV-18 mRNA (2/49, 4.08%). 27 cases were negative for mRNA16 and 18 (27/49, 55.1%). The prevalence of HPV was 68.8% (11/16) in the non-smoking group, which was higher than that of the smoking group (10/33, 33.3%), (χ2=5.463, P=0.019). There was no significant correlation between HPV detection and gender, age, drinking, tumor differentiation degree, and clinical stage (P > 0.05). The expression rates of P53, P21, and Cdc2 in OPSCC tissues were 63.3% (31/49), 65.3% (32/49), and 67.3% (33/49), respectively. There was no significant correlation between expression of all the three proteins and gender, age, HPV, smoking, drinking, tumor differentiation, and clinical stage (P > 0.05). Cox multifactor regression analysis showed that HPV (HR=0.275, 95% CI: 0.146-0.517), tumor differentiation (HR=1.751, 95% CI: 1.231-2.492), stage (HR=3.268, 95% CI: 1.758-6.074) and expression of Cdc2 protein (HR=1.804, 95% CI: 0.990-3.286) were related to the survival time of patients (P < 0.05). Our findings support that most of the HPV-positive OPSSC patients were non-smokers. The patients with negative HPV, low differentiation, late stage, and Cdc2 positive expression have poor prognosis and need to be followed up.
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Frameshift mutations frequently occur in colorectal cancer (CRC) with microsatellite instability (MSI), but the nature and biological function of many MSI-associated mutations remain elusive. Here, an MSI frameshift mutation is identified in glioma tumor suppressor candidate region gene 1 (GLTSCR1) that produces two C-terminal-truncated proteins. Additionally, GLTSCR1 is verified as a tumor suppressor that inhibits CRC metastasis. Through binding to bromodomains and the phosphorylation-dependent interaction domain of bromodomain protein 4 (BRD4) via the C-terminus, GLTSCR1 blocks oncogenic transcriptional elongation. However, truncated GLTSCR1 translocates into the cytoplasm and loses BRD4 binding domain, which induces the phosphorylation of RNA Pol II at Ser2 and dephosphorylation at Ser5, then increases oncogenic transcriptional elongation. Importantly, GLTSCR1 deficiency decreases sensitivity to bromodomain and extra terminal domain inhibitors. This study highlights the molecular mechanism of the GLTSCR1-BRD4 interaction, which is a potential therapeutic target for CRC.
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Ultrasmall and homogeneous bimetallic PdxBi nanoalloys are well distributed on a Vulcan carbon support by a facile, low-cost synthetic strategy. The electrochemical activity of the as-prepared homogeneous PdxBi nanoalloy/carbon black nanocomposites is closely related to the content of Bi, revealing their excellent electrocatalytic performance for selective oxidation of monohydric alcohols and vicinal diols in alkali medium.
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In this paper, magnetic NiFe2O4-RHC (rice husk carbon) catalysts with different NiFe2O4 contents are prepared through a one-step hydrothermal method and employed as a catalyst for the reduction of nitrophenols. The resulting catalysts are characterized using various techniques. It is indicated that the NiFe2O4 nanoparticles are well dispersed on the RHC with the average size of 9.97 nm and 224.13 m²·g-1 BET surface area. NiFe2O4-RHC (0.75) has the highest activity for the reduction of nitrophenols (k = 0°8872 min-1). The combination of NiFe2O4 nanoparticles with RHC results in a dramatic conversion of the inert NiFe2O4 into a highly active catalyst for the reduction of nitrophenols at 25 °C employing NaBH4 as the reducing agent in aqueous medium. The excellent catalytic performance of NiFe2O4-RHC (0.75) may be attributed to the specific characteristics of the nanostructure and the synergistic effect between NiFe2O4 and RHC. The effect of the substituent and temperature are also investigated. The activation energy was reduced to 15.342 kJ mol-1, facilitating the reaction at lower temperature. Furthermore, the catalyst NiFe2O4-RHC (0.75) is very cheap when RHC is introduced as the support compared to other carbon materials. The catalyst also exhibits magnetic performance and good stability; it can be used for 10 successive experiments with a conversion of 96%.
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OBJECTIVE: To investigate the molecular function of splicing factor SRSF6 in colorectal cancer (CRC) progression and discover candidate chemicals for cancer therapy through targeting SRSF6. DESIGN: We performed comprehensive analysis for the expression of SRSF6 in 311 CRC samples, The Cancer Genome Atlas and Gene Expression Omnibus (GEO) database. Functional analysis of SRSF6 in CRC was performed in vitro and in vivo. SRSF6-regulated alternative splicing (AS) and its binding motif were identified by next-generation RNA-sequencing and RNA immunoprecipitation sequencing (RIP-seq), which was validated by gel shift and minigene reporter assay. ZO-1 exon23 AS was investigated to mediate the function of SRSF6 in vitro and in vivo. Based on the analysis of domain-specific role, SRSF6-targeted inhibitor was discovered de novoby virtual screening in 4855 FDA-approved drugs and its antitumour effects were evaluated in vitroand in vivo. RESULTS: SRSF6 was frequently upregulated in CRC samples and associated with poor prognosis, which promoted proliferation and metastasis in vitro and in vivo. We identified SRSF6-regulated AS targets and discovered the SRSF6 binding motif. Particularly, SRSF6 regulates ZO-1 aberrant splicing to function as an oncogene by binding directly to its motif in the exon23. Based on the result that SRSF6 RRM2 domain plays key roles in regulating AS and biological function, indacaterol, a ß2-adrenergic receptor agonist approved for chronic obstructive pulmonary disease treatment, is identified as the inhibitor of SRSF6 to suppress CRC tumourigenicity. CONCLUSIONS: SRSF6 functions the important roles in mediating CRC progression through regulating AS, and indacaterol is repositioned as an antitumour drug through targeting SRSF6. ACCESSION NUMBERS: The accession numbers for sequencing data are SRP111763 and SRP111797.