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1.
Cancer Lett ; 597: 217047, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38871245

RESUMEN

Bone metastasis is common in breast cancer and more effective therapies are required, however, its molecular mechanism is poorly understood. Additionally, the role of the m6A reader YTHDF1 in bone metastasis of breast cancer has not been reported. Here, we reveal that the increased expression of YTHDF1 is clinically correlated with breast cancer bone metastases. YTHDF1 promotes migration, invasion, and osteoblast adhesion and induces osteoclast differentiation of cancer cells in vitro and vivo. Mechanically, RNA-seq, MeRIP-seq and RIP-seq analysis, and molecular biology experiments demonstrate that YTHDF1 translationally enhances EZH2 and CDH11 expression by reading m6A-enriched sites of their transcripts. Moreover, adeno-associated virus (AAV) was used to deliver shYTHDF1 (shYTHDF1-AAV) in intratibial injection models, eliciting a significant suppressive effect on breast cancer bone metastatic formation and osteolytic destruction. Overall, we uncovered that YTHDF1 promotes osteolytic bone metastases of breast cancer by inducing EZH2 and CDH11 translation.

2.
J Am Chem Soc ; 146(25): 16982-16989, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38870424

RESUMEN

Catalytic asymmetric dearomatization (CADA) reactions have evolved into an efficient strategy for accessing chiral polycyclic and spirocyclic scaffolds from readily available planar aromatics. Despite the significant developments, the CADA reaction of naphthalenes remains underdeveloped. Herein, we report a Gd(III)-catalyzed asymmetric dearomatization reaction of naphthalene with a chiral PyBox ligand via visible-light-enabled [4 + 2] cycloaddition. This reaction features application of a chiral Gd/PyBox complex, which regulates the reactivity and selectivity simultaneously, in excited-state catalysis. A wide range of functional groups is compatible with this protocol, giving the highly enantioenriched bridged polycycles in excellent yields (up to 96%) and selectivity (up to >20:1 chemoselectivity, >20:1 dr, >99% ee). The synthetic utility is demonstrated by a 2 mmol scale reaction, removal of directing group, and diversifications of products. Preliminary mechanistic experiments are performed to elucidate the reaction mechanism.

3.
Nat Commun ; 15(1): 2462, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38503749

RESUMEN

Medium-sized-ring compounds have been recognized as challenging synthetic targets in organic chemistry. Especially, the difficulty of synthesis will be augmented if an E-olefin moiety is embedded. Recently, photo-induced dearomative cycloaddition reactions that proceed via energy transfer mechanism have witnessed significant developments and provided powerful methods for the organic transformations that are not easily realized under thermal conditions. Herein, we report an intramolecular dearomative [5 + 4] cycloaddition of naphthalene-derived vinylcyclopropanes under visible-light irradiation and a proper triplet photosensitizer. The reaction affords dearomatized polycyclic molecules possessing a nine-membered-ring with an E-olefin moiety in good yields (up to 86%) and stereoselectivity (up to 8.8/1 E/Z). Detailed computational studies reveal the origin behind the favorable formation of the thermodynamically less stable isomers. Diverse derivations of the dearomatized products have also been demonstrated.

4.
Commun Biol ; 7(1): 91, 2024 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-38216635

RESUMEN

Bone metastasis is of common occurrence in renal cell carcinoma with poor prognosis, but no optimal treatment approach has been established for bone metastatic renal cell carcinoma. To explore the potential therapeutic targets for bone metastatic renal cell carcinoma, we profile single cell transcriptomes of 6 primary renal cell carcinoma and 9 bone metastatic renal cell carcinoma. We also include scRNA-seq data of early-stage renal cell carcinoma, late-stage renal cell carcinoma, normal kidneys and healthy bone marrow samples in the study to better understand the bone metastasis niche. The molecular properties and dynamic changes of major cell lineages in bone metastatic environment of renal cell carcinoma are characterized. Bone metastatic renal cell carcinoma is associated with multifaceted immune deficiency together with cancer-associated fibroblasts, specifically appearance of macrophages exhibiting malignant and pro-angiogenic features. We also reveal the dominance of immune inhibitory T cells in the bone metastatic renal cell carcinoma which can be partially restored by the treatment. Trajectory analysis showes that myeloid-derived suppressor cells are progenitors of macrophages in the bone metastatic renal cell carcinoma while monocytes are their progenitors in primary tumors and healthy bone marrows. Additionally, the infiltration of immune inhibitory CD47+ T cells is observed in bone metastatic tumors, which may be a result of reduced phagocytosis by SIRPA-expressing macrophages in the bone microenvironment. Together, our results provide a systematic view of various cell types in bone metastatic renal cell carcinoma and suggest avenues for therapeutic solutions.


Asunto(s)
Neoplasias Óseas , Carcinoma de Células Renales , Neoplasias Renales , Humanos , Carcinoma de Células Renales/genética , Neoplasias Renales/genética , Neoplasias Óseas/genética , Macrófagos/metabolismo , Microambiente Tumoral
5.
Cancer Med ; 2023 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-38102873

RESUMEN

BACKGROUND: Visceral sarcoma is a rare malignancy with a poor prognosis. However, there is no recommended prognostic staging system for the malignant disease. METHOD: We analyzed the data of patients diagnosed with primary soft tissue sarcoma (STS) of the abdomen and thoracic visceral organs between 2006 and 2017 at our hospital. Prognostic factors (size, tumor grade, and lymph node metastasis) were analyzed in our cohort (n = 203) and the SEER validation cohort (n = 5826). RESULTS: Tumor size, grade, and lymph node metastasis were important prognostic factors for visceral sarcoma in both our and the SEER cohorts. Based on these prognostic factors, we established a new staging system for visceral sarcoma, by which patients could be stratified into clinically meaningful and non-overlapping stages in both our cohort and the SEER validation series. Moreover, the area under the curve (AUC) value of the staging system for 5-year survival was 0.84 (95% CI: 0.78-0.89) in our series and 0.80 (95% CI: 0.79-0.81) in SEER series, respectively. In addition, compared with the widely used FIGO staging system for female genital sarcoma, the visceral sarcoma staging system could more effectively and reliably stratify patients into four different prognostic groups. CONCLUSIONS: The visceral sarcoma staging system is applicable for STS of the abdomen and thoracic visceral organs and is better than the current FIGO staging system for female genital sarcoma and should be incorporated into the AJCC Cancer Staging Manual.

6.
J Am Chem Soc ; 145(40): 21752-21759, 2023 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-37768553

RESUMEN

Chiral cyclobutane presents as a popular motif in natural products and biologically active molecules, and its derivatives have been extensively used as key synthons in organic synthesis. Herein, we report an efficient synthetic method toward enantioenriched cyclobutane derivatives. The reaction proceeds in a cascade fashion involving Ir-catalyzed asymmetric allylic etherification and visible-light induced [2 + 2] cycloaddition. Readily available branched allyl acetates and cinnamyl alcohols are directly used as the substrates under mild reaction conditions, providing a broad range of chiral cyclobutanes in good yields with excellent diastereo- and enantioselectivities (up to 12:1 dr, >99% ee). It is worth noting that all substrates and catalysts were simultaneously added without any separated step in this approach. The gram-scale reaction and diverse transformations of product further enhance the potential utility of this method.

7.
Angew Chem Int Ed Engl ; 62(34): e202307285, 2023 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-37379224

RESUMEN

Activation of C-C bonds allows editing of molecular skeletons, but methods for selective activation of nonpolar C-C bonds in the absence of a chelation effect or a driving force derived from opening of a strained ring are scarce. Herein, we report a method for ruthenium-catalyzed activation of nonpolar C-C bonds of pro-aromatic compounds by means of π-coordination-enabled aromatization. This method was effective for cleavage of C-C(alkyl) and C-C(aryl) bonds and for ring-opening of spirocyclic compounds, providing an array of benzene-ring-containing products. The isolation of a methyl ruthenium complex intermediate supports a mechanism involving ruthenium-mediated C-C bond cleavage.

8.
Genes Genomics ; 45(5): 611-625, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36445573

RESUMEN

BACKGROUND: Patients with non-small cell lung cancer (NSCLC) show a low survival rate, owing to the lack of early diagnostic method and high invasiveness. Long non-coding RNA MAPKAPK5-AS1 that regulates tumor genesis and progression through multiple signals, is upregulated and involved in the growth and apoptosis in lung adenocarcinoma (LUAD). OBJECTIVE: To investigate whether MAPKAPK5-AS1 affected the malignant progression of NSCLC. METHODS: The levels of MAPKAPK5-AS1, miR-490-3p and HMGB2 in lung cancer were first analyzed through StarBase website, and confirmed by a quantitative reverse transcriptase-PCR (qRT-PCR) assay. The biological functions of NSCLC cells were examined by CCK-8, 5-ethynyl-2'-deoxyuridine (EdU) and flow cytometry assays. The potential binding sequences lncRNA-miRNA and miRNA-mRNA were predicted by StarBase software and verified via dual luciferase reporter experiment. The effects of MAPKAPK5-AS1 on tumor growth were evaluated in a xenografted mice model. RESULTS: The expression of MAPKAPK5-AS1 was upregulated in tumor tissues from NSCLC patients. Patients with high expression of MAPKAPK5-AS1 had higher tumor size, advanced TNM stage, higher incidence of lymph node and distant metastasis, and shorter overall survival. Knockdown of MAPKAPK5-AS1 inhibited the proliferation, induced apoptosis and blocked epithelial mesenchymal transformation (EMT) of NSCLC cells. Mechanically, MAPKAPK5-AS1 could upregulate the HMGB2 level in NSCLC cells through competitively binding to miR-490-3p. MiR-490-3p inhibitor reversed the roles of MAPKAPK5-AS1 knockdown on tumor cell proliferation, apoptosis and EMT. Also, HMGB2 knockdown suppressed tumor cell malignant phenotypes. Furthermore, interference of MAPKAPK5-AS1 slowed NSCLC tumor growth in vivo. CONCLUSION: Knockdown of MAPKAPK5-AS1 inhibited the aggressive tumor phenotypes through miR-490-3p/HMGB2 axis in NSCLC. MAPKAPK5-AS1/miR-490-3p/HMGB2 might be potential biomarkers or therapeutic targets for NSCLC.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , MicroARNs , ARN Largo no Codificante , Animales , Ratones , Carcinoma de Pulmón de Células no Pequeñas/patología , Neoplasias Pulmonares/metabolismo , ARN Largo no Codificante/genética , Proteína HMGB2/genética , Transición Epitelial-Mesenquimal/genética , MicroARNs/genética , MicroARNs/metabolismo , Proliferación Celular/genética , Factores de Transcripción , Modelos Animales de Enfermedad , Pronóstico
9.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-986915

RESUMEN

Objective: To observe the clinical effect of auricle reconstruction in adult patients with microtia and summarize the experience. Methods: Clinical data of adult patients with microtia who underwent total auricle reconstruction using the modified Nagata's two stage for microtia reconstruction from June 2016 to June 2021 were analyzed. A total of 41 adult patients (42 ears) with microtia were enrolled, including 30 males and 11 females, with the median age at the time of surgery of 37 years. Autogenous costal cartilage was used as the auricular framework for all patients in this group. The first stage surgery was performed according to the modified Nagata's two stage for microtia reconstruction procedure,cartilage auricular framework carving was performed by different methods according to the ossification state of adult costal cartilage. Six months following the primary operation, ear elevation and cranioauricular angle formation, retroauricular facial flap transfer and medium-thick skin grafting were performed in the second stage. Results: All patients successfully completed two stage operation. During the follow-up of 3 months and 24 months, all the 41 patients were satisfied with the morphology of reconstructed auricle. Conclusion: According to the costal cartilage status of adult patients, different costal cartilage carving techniques can be used for total auricle reconstruction to obtain ideal surgical results.


Asunto(s)
Masculino , Femenino , Humanos , Adulto , Colgajos Quirúrgicos , Microtia Congénita/cirugía , Procedimientos de Cirugía Plástica , Oído Externo/cirugía , Pabellón Auricular/cirugía
10.
Orthop Surg ; 14(9): 2195-2202, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35975359

RESUMEN

OBJECTIVE: S2-alar-iliac (S2AI) screw technique is widely used in spinal surgery, but it is rarely seen in the field of spinal tumors. The aim of the study is to report the preliminary outcomes of the freehand S2AI screw fixation after lumbosaral tumor resection. METHODS: The records of patients with lumbosacral tumor who underwent S2AI screw fixation between November 2016 to November 2020 at our center were reviewed retrospectively. Outcome measures included operative time, blood loss, complications, accuracy of screws, screw breach, and overall survival. Mean ± standard deviation or range was used to present continuous variables. Kaplan-Meier curve was used to present postoperative survival. RESULTS: A total of 23 patients were identified in this study, including 12 males and 11 females, with an average age of 47.3 ± 14.5 (range,15-73). The mean operation time was 224.6 ± 54.1 (range, 155-370 min). The average estimated blood loss was 1560.9 ± 887.0 (600-4000 ml). A total of 46 S2AI screws were implanted by freehand technique. CT scans showed three (6.5%) screws had penetrated the iliac cortex, indicating 93.5% implantation accuracy rate. No complications of iatrogenic neurovascular or visceral structure were observed. The average follow-up time was 31.6 ± 15.3 months (range, 13-60 months). Two patients' postoperative plain radiography showed lucent zone around the screw. One patient underwent reoperation for wound delayed infection. At the latest follow-up, eight patients had tumor-free survival, 11 had survival with tumor, and four died of disease. CONCLUSION: The freehand S2AI screw technique is reproducible, safe, and reliable in the management of lumbosacral spinal tumors.


Asunto(s)
Fusión Vertebral , Neoplasias de la Columna Vertebral , Adulto , Tornillos Óseos , Femenino , Humanos , Ilion/cirugía , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Sacro/cirugía , Fusión Vertebral/métodos , Neoplasias de la Columna Vertebral/cirugía
11.
J Biol Chem ; 298(9): 102331, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35926708

RESUMEN

G protein-coupled olfactory receptors (ORs) enable us to detect innumerous odorants. They are also ectopically expressed in nonolfactory tissues and emerging as attractive drug targets. ORs can be promiscuous or highly specific, which is part of a larger mechanism for odor discrimination. Here, we demonstrate that the OR extracellular loop 2 (ECL2) plays critical roles in OR promiscuity and specificity. Using site-directed mutagenesis and molecular modeling, we constructed 3D OR models in which ECL2 forms a lid over the orthosteric pocket. We demonstrate using molecular dynamics simulations that ECL2 controls the shape and volume of the odorant-binding pocket, maintains the pocket hydrophobicity, and acts as a gatekeeper of odorant binding. Therefore, we propose the interplay between the specific orthosteric pocket and the variable, less specific ECL2 controls OR specificity and promiscuity. Furthermore, the 3D models created here enabled virtual screening of new OR agonists and antagonists, which exhibited a 70% hit rate in cell assays. Our approach can potentially be generalized to structure-based ligand screening for other G protein-coupled receptors that lack high-resolution 3D structures.


Asunto(s)
Odorantes , Receptores Odorantes , Olfato , Animales , Humanos , Ligandos , Ratones , Simulación de Dinámica Molecular , Mutagénesis Sitio-Dirigida , Conformación Proteica en Hélice alfa , Receptores Odorantes/química , Receptores Odorantes/genética , Olfato/fisiología
12.
Angew Chem Int Ed Engl ; 61(35): e202207917, 2022 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-35767354

RESUMEN

The use of alkylarenes as nucleophile precursors in benzylic addition is challenging because the benzylic hydrogen atoms of these compounds are inert to deprotonation. Herein, we report Rh-catalyzed benzylic addition of alkylarenes to Michael acceptors for the formation of C(sp3 )-C(sp3 ) bonds. The catalyst is proposed to activate the aromatic ring via η6 -coordination, dramatically facilitating deprotonation of the unactivated benzylic C-H bond and addition of the resulting carbanion to the α,ß-unsaturated double bond in the absence of bases. Notably, this byproduct-free method provides an access to all-carbon quaternary centers through the development of ligands.

13.
FASEB J ; 36(7): e22384, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35639289

RESUMEN

Odorant receptors (ORs) expressed in mammalian olfactory sensory neurons are essential for the sense of smell. However, structure-function studies of many ORs are hampered by unsuccessful heterologous expression. To understand and eventually overcome this bottleneck, we performed heterologous expression and functional assays of over 80 OR variants and chimeras. Combined with literature data and machine learning, we found that the transmembrane domain 4 (TM4) and its interactions with neighbor residues are important for OR functional expression. The data highlight critical roles of T4.62 therein. ORs that fail to reach the cell membrane can be rescued by modifications in TM4. Consequently, such modifications in MOR256-3 (Olfr124) also alter OR responses to odorants. T1614.62 P causes the retention of MOR256-3 in the endoplasmic reticulum (ER), while T1614.62 P/T1484.49 A reverses the retention and makes receptor trafficking to cell membrane. This study offers new clues toward wide-range functional studies of mammalian ORs.


Asunto(s)
Receptores Odorantes , Animales , Membrana Celular/metabolismo , Mamíferos/metabolismo , Odorantes , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Olfato
14.
ACS Cent Sci ; 8(3): 379-387, 2022 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-35350604

RESUMEN

G protein-coupled receptors (GPCRs) conserve common structural folds and activation mechanisms, yet their ligand spectra and functions are highly diverse. This work investigated how the amino-acid sequences of olfactory receptors (ORs)-the largest GPCR family-encode diversified responses to various ligands. We established a proteochemometric (PCM) model based on OR sequence similarities and ligand physicochemical features to predict OR responses to odorants using supervised machine learning. The PCM model was constructed with the aid of site-directed mutagenesis, in vitro functional assays, and molecular simulations. We found that the ligand selectivity of the ORs is mostly encoded in the residues up to 8 Å around the orthosteric pocket. Subsequent predictions using Random Forest (RF) showed a hit rate of up to 58%, as assessed by in vitro functional assays of 111 ORs and 7 odorants of distinct scaffolds. Sixty-four new OR-odorant pairs were discovered, and 25 ORs were deorphanized here. The best model demonstrated a 56% deorphanization rate. The PCM-RF approach will accelerate OR-odorant mapping and OR deorphanization.

15.
Front Surg ; 8: 686930, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34881284

RESUMEN

Objective: This study aimed to compare the outcomes between piecemeal spondylectomy and separation surgery for patients with spinal metastasis. Summary of Background Data: Piecemeal spondylectomy and separation surgery are two widely-used treatment options for spinal metastasis. However, no studies have compared the surgical outcomes between both treatment modalities. Methods: Patients with spinal metastasis who underwent piecemeal spondylectomy or separation surgery between August 2017 and April 2020 at our spine center were recruited. Demographic, preoperative, perioperative, and follow-up data were collected and analyzed. Kaplan-Meier analysis and the log-rank test were used to analyze overall survival (OS) and progression-free survival (PFS) in patients with spinal metastasis. Results: Overall, 26 patients were treated with piecemeal spondylectomy, and 29 underwent separation surgery with postoperative stereotactic radiosurgery. Both groups showed significant postoperative improvements in neurological status. The piecemeal spondylectomy group had significantly more blood loss (1784.62 ± 833.64 vs. 1165.52 ± 307.38 ml) and required longer operative time (4.76 ± 0.93 vs. 3.73 ± 1.15 h) than the separation surgery group. No significant difference in OS was found between the groups (P = 0.064); however, patients in the separation surgery group experienced less local recurrence than those in the piecemeal spondylectomy group (P = 0.0014). Notably, significant differences were detected in the development of complications between the groups (P = 0.029). Conclusion: Separation surgery led to less blood loss and reduced complications and had shorter operation time than piecemeal spondylectomy. Although no significant differences were found in OS between the groups, separation surgery was associated with better PFS compared with piecemeal spondylectomy. These findings suggest that separation surgery has some advantages over piecemeal spondylectomy for patients with spinal metastatic disease.

16.
Med Sci Monit ; 27: e933351, 2021 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-34857728

RESUMEN

BACKGROUND We analyzed the correlation among the inflammatory changes in pericarotid adipose tissue (PCAT), plaque characteristics, and H-type hypertension on CT angiography (CTA) and explored the utility of CTA in the prevention and treatment of carotid atherosclerosis. MATERIAL AND METHODS A total of 135 patients who underwent head and neck CTA to investigate carotid artery atherosclerosis were retrospectively analyzed. The plaque characteristic parameters (plaque burden and remodeling index), PCAT attenuation value, and net enhancement value around the carotid artery, where the plaques were located, were recorded, and confounding factors were matched by propensity score analysis. A paired t test was used to compare the differences in fat tissue inflammatory changes and plaque characteristic parameters between the 2 groups, and logistic regression analysis was used to evaluate the relationship between plaque characteristics and the attenuation values and net enhancement values of PCAT. The correlation coefficient was calculated between type H hypertension and plaque risk grade. RESULTS The results of the experiment indicate that PCAT attenuation values and net enhancement values gradually increased as the degree of hypertension increased. Compared with those of patients in the normal Hcy group, these values increased more clearly in patients with high Hcy (HHcy) (r=0.641, P<0.001, r=0.581, P<0.001), although, regardless of whether the Hcy value increased, there were significant differences between the groups. However, this effect was more pronounced in patients with H-type hypertension. Logistic regression analysis of risk factors for carotid atherosclerotic plaque suggests that Hcy (OR=1.391, 95% CI 1.146-1.689, P=0.001), PCAT attenuation values (OR=1.212, 95% CI 1.074-1.367, P=0.002), and net enhancement values (OR=1.201, 95% CI 1.042-1.383, P=0.011) were independent risk factors for plaque vulnerability. CONCLUSIONS Our results suggest that H-type hypertension is significantly associated with PCAT attenuation and net enhancement and that PCAT net enhancement values are useful in predicting plaque risk as attenuation.


Asunto(s)
Tejido Adiposo/diagnóstico por imagen , Tejido Adiposo/fisiopatología , Angiografía por Tomografía Computarizada/métodos , Hipertensión/fisiopatología , Placa Aterosclerótica/diagnóstico por imagen , Placa Aterosclerótica/fisiopatología , Anciano , Femenino , Humanos , Masculino , Puntaje de Propensión , Estudios Retrospectivos , Factores de Riesgo
17.
Nat Commun ; 12(1): 5881, 2021 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-34620857

RESUMEN

Hydroalkylation, the direct addition of a C(sp3)-H bond across an olefin, is a desirable strategy to produce valuable, complex structural motifs in functional materials, pharmaceuticals, and natural products. Herein, we report a reliable method for accessing α-branched amines via nickel-catalyzed hydroalkylation reactions. Specifically, by using bis(cyclooctadiene)nickel (Ni(cod)2) together with a phosphine ligand, we achieved a formal C(sp3)-H bond insertion reaction between olefins and N-sulfonyl amines without the need for an external hydride source. The amine not only provides the alkyl motif but also delivers hydride to the olefin by means of a nickel-engaged ß-hydride elimination/reductive elimination process. This method provides a platform for constructing chiral α-branched amines by using a P-chiral ligand, demonstrating its potential utility in organic synthesis. Notably, a sulfonamidyl boronate complex formed in situ under basic conditions promotes ring-opening of the azanickellacycle reaction intermediate, leading to a significant improvement of the catalytic efficiency.

18.
J Am Chem Soc ; 143(33): 13441-13449, 2021 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-34398603

RESUMEN

Visible-light-induced cycloaddition reactions initiated via energy-transfer processes have recently evolved as powerful methods for the construction of strained cyclic molecules that are not easily accessed using known ground-state synthetic methods. Particularly, the reactions initiated by the excitation of aromatic rings provide an alternative solution to the direct transformations of aromatic feedstocks under the scheme of dearomatization. Vinylcyclopropanes (VCPs) are well-known reagents in radical clock experiments, working as a probe to detect transient radical intermediates. However, the synthetic applications in this regard still remain limited due to uncontrollable selectivities. Herein, we report visible-light-induced dearomatization of indole- or pyrrole-tethered VCPs, in which several competitive reaction pathways, including [5 + 2], [2 + 2], interrupted [5 + 2], and [5 + 4] cycloadditions, can be well regulated by engineering substrate structures and tuning reaction conditions. The reaction mechanism has been explored by combined experimental and computational investigations. These reactions provide a convenient method to synthesize structurally diverse polycyclic molecules with high efficiency and good selectivity.

19.
Angew Chem Int Ed Engl ; 60(37): 20391-20399, 2021 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-34263536

RESUMEN

Nucleophilic aromatic substitution (SN Ar) is a powerful strategy for incorporating a heteroatom into an aromatic ring by displacement of a leaving group with a nucleophile, but this method is limited to electron-deficient arenes. We have now established a reliable method for accessing phenols and phenyl alkyl ethers via catalytic SN Ar reactions. The method is applicable to a broad array of electron-rich and neutral aryl fluorides, which are inert under classical SN Ar conditions. Although the mechanism of SN Ar reactions involving metal arene complexes is hypothesized to involve a stepwise pathway (addition followed by elimination), experimental data that support this hypothesis is still under exploration. Mechanistic studies and DFT calculations suggest either a stepwise or stepwise-like energy profile. Notably, we isolated a rhodium η5 -cyclohexadienyl complex intermediate with an sp3 -hybridized carbon bearing both a nucleophile and a leaving group.

20.
Front Oncol ; 11: 624240, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34123783

RESUMEN

AIMS: Dysregulated long noncoding RNAs (lncRNAs) contributing to ovarian cancer (OC) development may serve as prognostic biomarker. We aimed to explore a lncRNA signature to serve as prognostic biomarker of OC. METHODS: Univariate Cox regression was conducted on the lncRNA expression dataset from the TCGA cohort, and 246 genes significantly associated with survival were retained for building a model. A random forest survival model was carried out, and a model was developed using 6 genes with the highest frequency. The selected genes were applied in a Cox multivariate regression model for prognostic prediction by calculating the risk score. We also used CCK-8, EdU, and colony formation assays to validate the function of these lncRNAs in OC cells. RESULTS: This study confirmed that the 6-lncRNA combined signature was related to OC prognosis. Systematic analysis demonstrated that lncRNA-associated genes were enriched in oncogenic signalling pathways. Five out of the 6 lncRNAs participated in OC proliferation. CONCLUSION: We established a 6-lncRNA combined signature for OC prognosis, which may serve as powerful prognostic biomarker for OC after further validation.

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