The Respiratory Burst Oxidase Homologue OsRBOHE is crucial for root hair formation, drought resistance and tillering in rice.

Respiratory Burst Oxidase Homologues (RBOHs) are involved in plant growth, development, and stress adaptation. How OsRBOHs affect root hair formation and consequently nutrient acquisition and drought resistance in rice is not well understood. We knocked out six OsRBOH genes in rice that were expressed in roots and identified OsRBOHE as the only one affecting root hair formation. OsRBOHE was strongly expressed in the root epidermis, root hairs and tiller buds. OsRBOHE is localised at the plasma membrane. Knockout of OsRBOHE decreased reactive oxygen species generation in the root hairs and tiller buds, downregulated genes involved in cell wall biogenesis, and decreased root hair length and tillering by 90% and 30%, respectively. Knockout of OsRBOHE decreased phosphorus acquisition only in low available P soil under aerobic conditions, but not in high P soil or under flooded conditions when P was likely not limited by diffusion. Knockout of OsRBOHE markedly decreased drought resistance of rice plants through the effect on root hair formation and the associated rhizosheath. Taken together, OsRBOHE is crucial for root hair formation and tillering and consequently on drought resistance in rice. The contribution of root hairs to P acquisition in rice is limited to aerobic soil.

Coordination Assistance: A Powerful Strategy for Metal-Catalyzed Regio- and Enantioselective Hydroalkynylation of Internal Alkenes.

ConspectusAlkenes are versatile compounds that are readily available on a large scale from industry or through organic synthesis. The widespread occurrence of alkenes provides the continuous impetus for the development of catalytic asymmetric alkene hydrofunctionalizations, which enables expeditious construction of complex chiral molecules from readily available starting materials. Catalytic asymmetric hydrofunctionalization of internal alkenes presents a notable challenge, due to their low reactivity, many potential side reactions, and the simultaneous control of the regio-, diastereo-, and enantioselectivities.Dehydroamino acids and enamides are among the first substrates that provide notable enantioselectivities in catalytic asymmetric hydrogenation. The crucial importance of an amide coordinating group is established by a series of classical mechanistic studies. This initial success greatly stimulated further development for catalytic hydrogenation and hydrofunctionalization. Building on these pioneering works in asymmetric hydrogenation as well as related hydrofunctionalizations, we have adopted coordination assistance as a powerful tool to address the challenges associated with the asymmetric hydrofunctionalization of internal alkenes. Using a functional group on the alkene substrate as a native coordinating group, a two-point binding mode of the substrate to the metal center effectively enhances the reactivity and facilitates the control of regio-, diastereo- and enantioselectivities. Through this strategy, we have developed a number of alkene hydrofunctionalization methods with excellent regio-, diastereo-, and enantiocontrols.In this Account, we summarize the recent advance in our lab using coordination assistance as a key element to achieve regio- and enantioselective hydroalkynylation of internal alkenes. First, we describe our early work aimed at controlling the regio- and enantioselectivity of hydroalkynylation using disubstituted enamide as the substrate. Both α- and ß-alkynylation were achieved by channeling the reaction pathway into a Chalk-Harrod or modified Chalk-Harrod mechanism. Next, we discuss the further development of catalysts to achieve regiodivergent and enantioselective hydroalkynylation of trisubstituted enamide to access vicinal stereocenters and quaternary carbon stereocenters. We also discuss the hydroalkynylation of α,ß-unsaturated amides to achieve unconventional site-selectivity through a combination of alkene isomerization and regioselective hydroalkynylation. This provides the basis for the construction of a remote quaternary carbon stereocenter through catalytic hydroalkynylation of trisubstituted ß,γ-unsaturated amides. We further show that this controlling principle is applicable to terminal alkene with a coordinating group as well. A ligand-controlled mechanism shift is discussed for the enantioselective alkynylation at the terminal and internal position of 1,1,-disubstituted alkenes. Finally, we briefly mention the application of coordination assistance to other hydrofunctionalizations such as hydroboration and hydrosilylation, where previously inaccessible reactivity and selectivity were achieved. Collectively, these catalytic methods demonstrate the power of coordination assistance for enantioselective hydrofunctionalizations. We anticipate that this strategy will create a platform to enable diverse enantioselective alkene transformations.

Electrophile-Arene Affinity: An Energy Scale for Evaluating the Thermodynamics of Electrophilic Dearomatization Reactions.

Rational design and development of organic reactions are lofty goals in synthetic chemistry. Quantitative description of the properties of molecules and reactions by physical organic parameters plays an important role in this regard. In this Article, we report an energy scale, namely, electrophile-arene affinity (EAA), for evaluating the thermodynamics of electrophilic dearomatization reactions, a class of important transformations that can rapidly build up molecular complexity and structural diversity by converting planar aromatic compounds into three-dimensional cyclic molecules. The acquisition of EAA data can be readily achieved by theoretically calculating the enthalpy changes (ΔH) of the hypothetical reactions of various (cationic) electrophiles with aromatic systems (taking the 1-methylnaphthalen-2-olate ion as an example in this study). Linear correlations are found between the calculated ΔH values and established physical organic parameters such as the percentage of buried volume %VBur (steric effect), Hammett's σ or Brown's σ+ (electronic effect), and Mayr's E (reaction kinetics). Careful analysis of the ΔH values leads to the rational design of a dearomative alkynylation reaction using alkynyl hypervalent iodonium reagents as the electrophiles.

Effects of silencing hsa_circ_0015326 on proliferation, migration, invasion, and apoptosis of epithelial ovarian cancer cells.

Although the treatment of ovarian cancer has made great progress, there are still many patients who are not timely detected and given targeted therapy due to unknown pathogenesis. Recent studies have found that hsa_circ_0015326 is upregulated in ovarian cancer and is involved in the proliferation, invasion, and migration of ovarian cancer cells. However, whether hsa_circ_0015326 can be used as a new target of ovarian cancer needs further investigation. Therefore, the effect of hsa_circ_0015326 on epithelial ovarian cancer was investigated in this study. At first, si-hsa_circ_0015326 lentivirus was transfected into epithelial ovarian cancer cells. Then real-time fluorescence quantitative PCR (qRT-PCR) was used to detect hsa_circ_0015326 level. The proliferation of ovarian cancer cells was detected by CCK-8 assay. The horizontal and vertical migration abilities of the cells were detected by wound-healing assay and Transwell assay, respectively. Transwell assay was also used to determine the invasion rate. As for the apoptosis rate, it was assessed by flow cytometry. As a result, the expression level of hsa_circ_0015326 in A2780 and SKOV3 was found to be higher than that in IOSE-80. However, after transfecting si-hsa_circ_0015326 and si-NC into the cells, the proliferation, migration, and invasion abilities of A2780 and SKOV3 cells in the si-hsa_circ_0015326 group were significantly reduced in comparison to those in the si-NC and mock groups, while their apoptosis rates were elevated. Collectively, silencing hsa_circ_0015326 bears the capability of inhibiting the proliferation, migration, and invasion of ovarian cancer cells while increasing apoptosis rate. It can be concluded that hsa_circ_0015326 promotes the malignant biological activities of epithelial ovarian cancer cells.

PRAME is a useful marker for the differential diagnosis of melanocytic tumours and histological mimics.

AIMS: Although the morphological assessment of melanoma is generally straightforward, diagnosis can be especially difficult when the significant morphological and immunohistochemical results overlap with those of benign and malignant melanocytic tumours and histological mimics. This study assessed the potential diagnostic utility of measuring PReferentially expressed Antigen in MElanoma (PRAME) immunohistochemically in naevi, melanomas and clear cell sarcomas (CCSs) in Chinese patients. METHODS: We examined the immunohistochemical expression of PRAME in 317 melanocytic naevi, 178 primary melanomas, 72 metastatic melanomas and 19 CCSs and compared the sensitivity and specificity of PRAME immunohistochemistry (IHC) in the differential diagnosis of melanocytic tumours and histological mimics. RESULTS: Of the 317 melanocytic naevi, 98.1%were completely negative for PRAME; six cases showed focal PRAME immunoreactivity in a minor population of lesional melanocytes. Diffuse nuclear immunoreactivity for PRAME was found in 89.9% of primary melanomas and 93.1% of metastatic melanomas. Regarding melanoma subtypes, PRAME was expressed in 100% of superficial spreading melanomas, 100% of melanomas arise in congenital naevus, 91.4% of nodular melanomas, 87.8% of acral lentigo melanomas, 80.0% of lentigo malignant melanomas, 60.0% of Spitz melanomas, 96.2% of mucosal melanomas and 80.0% of uveal melanomas. None of the two desmoplastic melanomas expressed PRAME. Of the 19 CCS cases, 89.5% were negative for PRAME and 10.5% showed focal weak PRAME immunoreactivity in a minor population of tumour cells. CONCLUSIONS: Our findings indicate that PRAME may be a useful marker to support a suspected diagnosis of melanoma. In addition, lack of PRAME expression is a valuable hint to CCS in a suspected case, and then molecular confirmation of the presence of EWSR1 rearrangement is necessary.

Alterations of Spontaneous Cortical and Subcortical Activity in Type 2 Diabetes Mellitus with and without Depression.

INTRODUCTION: Type 2 diabetes mellitus (T2DM) patients with depression have a higher risk of complications and mortality than T2DM without depression. However, the exact neuropathophysiological mechanism remains unclear. Consequently, the current study aimed to investigate the alteration of cortical and subcortical spontaneous neural activity in T2DM patients with and without depression. METHODS: The demographic data, clinical variables, neuropsychological tests, and functional and anatomical magnetic resonance imaging of depressed T2DM (n = 47) of non-depressed T2DM (n = 59) and healthy controls (n = 41) were collected and evaluated. The correlation analysis, stepwise multiple linear regression, and receiver operating characteristic curve were performed for further analysis. RESULTS: Abnormal neural activities in the bilateral posterior cingulate cortex (PCC) and hippocampus were observed in depressed and non-depressed T2DM and the right putamen of the depressed T2DM. Interestingly, the subcortical degree centrality (DC) of the right hippocampus and putamen were higher in depressed than non-depressed T2DM. Furthermore, the cortical amplitude of low-frequency fluctuation (ALFF) in PCC, subcortical DC in the putamen of depressed T2DM, and hippocampus of non-depressed T2DM was correlated with cognitive scores. In contrast, the cortical fractional ALFF in PCC of non-depressed T2DM was correlated with depression scores. CONCLUSIONS: The abnormalities of spontaneous cortical activity in PCC and subcortical activity in the hippocampus might represent the neurobiological feature of cerebral dysfunction in T2DM. Notably, the altered subcortical activity in the right putamen might mainly associate with negative emotion in T2DM, which could be a promising biomarker for recognizing early cerebral dysfunction in depressed T2DM. This study provided a novel insight into the neuropathophysiological mechanism of brain dysfunction in T2DM with and without depression.

Dendrocandin U from Dendrobium officinale Kimura et Migo Inhibits M1 Polarization in Alveolar Macrophage by Suppressing NF-κB Signaling Pathway.

Dendrobium officinale Kimura et Migo is a valuable and homologous medicine and food traditional Chinese medicine. Currently there are few studies on the anti-inflammatory activity of lipophilic components. The aim of this study was to explore the anti-inflammatory effect and mechanism of the lipophilic compounds in Dendrobium officinale. Six compounds were isolated and identified, including three bibenzyl compounds, dendrocandin U, dendronbibisline B, erianin, and three lignans, (-)-syringaresinol, (+)-syringaresinol-O-ß-D-glucopyranoside, 5-methoxy-(+)-isolariciresinol. Among them, dendronbibisline B and 5-methoxy-(+)-isolariciresinol were isolated from Dendrobium officinale for the first time. Besides, we found dendrocandin U, dendronbibisline B and (-)-syringaresinol exhibited the anti-inflammation to inhibit nitric oxide secretion induced by lipopolysaccharide (LPS)/interferon (IFN-γ) in MH-S cells. Furthermore, dendrocandin U could inhibit the expression of tumor necrosis factor-α (TNF-α), Cluster of Differentiation 86 (CD86), and reduce inflammatory morphological changes of macrophages. Meanwhile, we confirmed that the anti-inflammation mechanism of dendrocandin U was to inhibit M1 polarization by suppressing toll-like receptor 4 (TLR4)/recombinant myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) signaling pathway. In this paper, dendrocandin U with significant anti-inflammatory activity was found from Dendrobium officinale, which could provide a basis for the study of its anti-inflammatory drugs.

Climate co-benefits of VOC control policies in China based on a cross-scale approach.

Volatile organic compounds (VOC) contributing to smog formation, have been an important indicator of atmospheric governance during China's "14th Five-Year Plan". VOC would be possibly incorporated into the scope of environmental protection tax, but previous studies have seldom explored impacts of VOC control policies at national and regional levels. Here, we design a national uniform VOC control policy, as well as two regionally differentiated policies based on regional disparities in PM2.5 concentrations and energy intensity by using a cross-scale dynamic computable general equilibrium (CGE) model. Our analysis is to assess the impacts of these policies on VOC, CO2, sulfur dioxide (SO2), nitrogen oxides (NOX), and PM2.5 emissions, air quality and environmental equity, and to estimate health benefits, policy costs and net benefits. We find that national and regionally differentiated VOC control policies generally lead to VOC emission reductions and generate co-benefits on emission reductions in CO2, SO2, NOX and PM2.5 at national and provincial levels. However, regional emission leakage exists due to differences in the provincial costs of VOC mitigation. The regionally differentiated VOC pricing policies are found to be more effective to enhance environmental equity than the uniform policy. In particular, the regionally differentiated VOC control policy based on provincial energy efficiency is found to be superior to other policies in terms of improve air quality. Furthermore, the human health benefits associated with VOC pricing policies would partially offset policy costs at both the national and regional levels. Our results suggest that policymakers would pay attention to developing regions with low energy efficiency which have the great emission reduction potential. Advanced producing technology and further end-of-pipe control measures to reduce non-combustion PM2.5 emissions are needed. VOC policy designed based on provincial energy efficiency provides great insights for environmental policy making to accomplish 2035 goal of building a Beautiful China.

[Comparison of alkaloids in Aconiti Kusnezoffii Radix, Aconiti Radix, and Aconiti Lateralis Radix Praeparata based on UHPLC-Q-Exactive Orbitrap MS/MS].

UHPLC-Q-Exactive Orbitrap MS/MS was used to systematically analyze and compare the alkaloids in Aconiti Kusnezoffii Radix, Aconiti Radix, and Aconiti Lateralis Radix Praeparata. After the samples were pretreated in the solid-phase extraction cartridges, 0.1% ammonium hydroxide(A)-acetonitrile(B) was used for gradient elution. The LC-MS method for characterization of alkaloids in the three herbal medicines was established in ESI positive ion mode to collect high resolution MS data of reference substances and samples. On the basis of the information of reference substance cracking behavior, retention time, accurate molecular mass, and related literature, a total of 155 alkaloids were identified in Aconiti Kusnezoffii Radix, Aconiti Radix, and Aconiti Lateralis Radix Prae-parata. Specifically, 130, 127, and 92 alkaloids were identified in Aconiti Kusnezoffii Radix, Aconiti Radix, and Aconiti Lateralis Radix Praeparata, respectively. Monoester alkaloids and amino-alcohol alkaloids were dominant in the three herbal medicines, and the alkaloids in Aconiti Kusnezoffii Radix and Aconiti Radix were similar. This paper can provide a reference for elucidating the pharmacological effects and clinical application differences of the three herbal medicines produced from plants of Aconitum.

Enantioselective Hydrosilylation of ß,ß-Disubstituted Enamides to Construct α-Aminosilanes with Vicinal Stereocenters.

Despite the advances in the area of catalytic alkene hydrosilylation, the enantioselective hydrosilylation of alkenes bearing a heteroatom substituent is scarce. Here we report a rhodium-catalyzed hydrosilylation of ß,ß-disubstituted enamides to directly afford valuable α-aminosilanes in a highly regio-, diastereo-, and enantioselective manner. Stereodivergent synthesis could be achieved by regulating substrate geometry and ligand configuration to generate all the possible stereoisomers in high enantio-purity.

(SCp)Rhodium-Catalyzed Asymmetric Satoh-Miura Reaction for Building-up Axial Chirality: Counteranion-Directed Switching of Reaction Pathways.

Satoh-Miura reaction is an important method for extending π-systems by forging multi-substituted benzene rings via double aryl C-H activation and annulation with alkynes. However, the development of highly enantioselective Satoh-Miura reaction remains rather challenging. Herein, we report an asymmetric Satoh-Miura reaction between 1-aryl benzo[h]isoquinolines and internal alkynes enabled by a SCpRh-catalyst. Judiciously choosing the counteranion of the Rh-catalyst is crucial for the desired reactivity over the competitive formation of azoniahelicenes. Detailed mechanistic studies support the proposal of counteranion-directed switching of reaction pathways in Rh-catalyzed asymmetric C-H activation.

Prognostic significance of the skeletal muscle index and systemic inflammatory index in patients with lymph node-positive breast cancer after radical mastectomy.

BACKGROUND: The role of skeletal muscle index (SMI) and systemic inflammation index (SII) for patients with lymph node-positive breast cancer remain controversial. This retrospective study aims to evaluate the individual and synergistic value of SMI and SII in outcomes prediction in this population. METHODS: Lymph node-positive breast cancer patients who received mastectomy between January 2011 and February 2013 were included in this retrospective study. We used abdominal computed tomography (CT) to measure skeletal muscle mass at the third lumbar (L3) level. The optimal cut-off values of SMI and SII were determined through maximizing the Youden index on the receiver operating characteristic (ROC) curves. Kaplan-Meier method was used to assess the correlation between SMI, SII, and overall survival (OS). The prognostic value of SMI and SII were analyzed with the multivariable Cox proportional hazards model. RESULTS: Of 97 patients included in our study (mean age: 46 [range: 27-73] years; median follow-up: 62.5 months), 71 had low SMI (sarcopenia), 59 had low SII, and 56 had low SMI + SII. Kaplan-Meier survival curves showed that both high SMI (P = 0.021, 5-year OS: 84.0% vs. 94.1%) and high SII (P = 0.043, 5-year OS: 81.0% vs. 97.3%) were associated with worse OS. Additionally, patients with either low SMI or low SII had significantly better OS (P = 0.0059, 5-year OS: 100.0% vs. 84.6%) than those with high SMI + SII. Multivariable analysis confirmed the predictive values of high SMI (P = 0.024, hazard ratio [HR]: 9.87) and high SII (P = 0.048, HR: 6.87) for poor OS. Moreover, high SMI + SII was significantly associated with poor survival (P = 0.016, HR: 16.36). CONCLUSIONS: In this retrospective analysis, both SMI and SII independently predicted the prognosis of patients with lymph node-positive breast cancer. SMI + SII might be a stronger prognostic factor than either alone based on our findings, but should be further verified in a larger study.

Light-emitting diode phototherapy: pain relief and underlying mechanisms.

Pain is a common symptom of an illness. For decades, pain treatments such as non-steroidal anti-inflammatory drugs, opioids, and surgical nerve blocking have been widely used, but each method has its limitations. Photobiomodulation is a recently developed method for pain management, with light-emitting diodes (LEDs) being a more recent development used in pain management because of their low cost, low side effects, and high safety. Here, we reviewed the phototherapeutic effects of LEDs on different pain conditions. We also discussed possible physicochemical and neurobiological mechanisms underlying LED therapy, especially its effects on inflammatory pain.

The Analytical Strategy of "Ion Induction and Deduction Based on Net-Hubs" for the Comprehensive Characterization of Naringenin Metabolites In Vivo and In Vitro Using a UHPLC-Q-Exactive Orbitrap Mass Spectrometer.

Naringenin (5,7,4'-trihydroxyflavanone), belonging to the flavanone subclass, is associated with beneficial effects such as anti-oxidation, anticancer, anti-inflammatory, and anti-diabetic effects. Drug metabolism plays an essential role in drug discovery and clinical safety. However, due to the interference of numerous endogenous substances in metabolic samples, the identification and efficient characterization of drug metabolites are difficult. Here, ultra-high-performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry was used to obtain mass spectral information of plasma (processed by three methods), urine, feces, liver tissue, and liver microsome samples. Moreover, a novel analytical strategy named "ion induction and deduction" was proposed to systematically screen and identify naringenin metabolites in vivo and in vitro. The analysis strategy was accomplished by the establishment of multiple "net-hubs" and the induction and deduction of fragmentation behavior. Finally, 78 naringenin metabolites were detected and identified from samples of rat plasma, urine, feces, liver tissue, and liver microsomes, of which 67 were detected in vivo and 13 were detected in vitro. Naringenin primarily underwent glucuronidation, sulfation, oxidation, methylation, ring fission, and conversion into phenolic acid and their composite reactions. The current study provides significant help in extracting target information from complex samples and sets the foundation for other pharmacology and toxicology research.

[Identification of metabolites of imperatorin in rats: based on UHPLC-Q-Exactive Orbitrap MS].

This study aims to identify and analyze the metabolites of imperatorin in rats by UHPLC-Q-Exactive Orbitrap MS. Specifically, after rats were treated(ig) with imperatorin, the plasma, urine, and feces were collected, and the samples were processed by solid phase extraction. Then, UHPLC-Q-Exactive Orbitrap MS was performed. In MS, 0.1% formic acid water(A)-acetonitrile(B) was applied as mobile phase for gradient elution and the data of MS in both positive and negative ion modes were collected. The metabolites of imperatorin in blood, urine, and feces of rats were analyzed to explore the metabolic pathways of imperatorin in rats. According to accurate molecular weight, multistage MS data, MS fragmentation rule of the standard substance, and previous reports, a total of 51 metabolites were identified, with 35, 40, and 16 from plasma, urine, and feces, separately. The main metabolic pathways were oxidization, glucuronidation, isopentenyl removal, sulphation, carboxylation, among others. The conclusion in this study is expected to serve as a reference for the further development and the further pharmacodynamics study of imperatorin.

[Identification of chemical constituents of Xiaochengqi Decoction by UPLC-Q-TOF/Fast DDA combined with UNIFI software].

Based on the combination of ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF) and Waters UNIFI software, the chemical constituents of the classic prescription Xiaochengqi Decoction were qualitatively analyzed and identified. The UPLC conditions are as follows: Acquity HSS T3 reverse phase column(2.1 mm ×100 mm, 1.8 µm), column temperature of 30 ℃, mobile phase of 0.1% formic acid aqueous solution(A)-acetonitrile(B), and flow rate of 0.3 mL·min~(-1). High-resolution MS data of Xiaochengqi Decoction were collected in ESI~(+/-) modes by Fast DDA. The structures of the chemical constituents were tentatively characterized or identified by UNIFI software according to the retention time of reference standards and characteristic fragment ions in MS profile, and literature data. A total of 233 components in Xiaochengqi Decoction were identified, with 93 from wine-processed Rhei Radix et Rhizoma, 104 from bran-processed Aurantii Fructus Immaturus, and 36 from ginger-processed Magnoliae Officinalis Cortex. These 233 components included anthraquinones, flavonoids, lignans, alkaloids, coumarins, and phenylethanoid glycosides. The result provided experimental evidence for the further study on establishment of quality standard and product development of the formula.

Ir-Catalyzed Regio- and Enantioselective Hydroalkynylation of Trisubstituted Alkene to Access All-Carbon Quaternary Stereocenters.

The stereoselective construction of all-carbon quaternary stereocenters, especially acyclic ones, represents an important challenge in organic synthesis. In particular, homopropargyl amides with a quaternary stereocenter ß to a nitrogen atom are valuable synthetic intermediates, which could be transformed to diverse chiral structures through alkyne transformations. However, highly enantioselective synthetic methods for homopropargyl amides with a ß quaternary stereocenter are extremely rare. We report here unprecedented substrate-directed, iridium-catalyzed enantioselective hydroalkynylations of trisubstituted alkenes to form an acyclic all-carbon quaternary stereocenter ß to a nitrogen atom. The hydroalkynylation of enamide occurred with unconventional selectivity, favoring the more hindered reaction site. Homopropargyl amides with ß-stereocenters were prepared in high regio- and enantioselectivities. Combined experimental and computational studies revealed the origin of the regio- and enantioselectivities.

Enantioselective Synthesis of Azoniahelicenes by Rh-Catalyzed C-H Annulation with Alkynes.

A rhodium(III)-catalyzed enantioselective C-H activation/annulation process is disclosed. With a catalyst derived from a chiral CpRh(III) complex and a chiral acid, the direct annulation reactions between 1-aryl isoquinoline derivatives and alkynes take place smoothly to afford a series of chiral azoniahelicenes in excellent yields and enantioselectivity (up to 99% yield and 96% ee). Mechanistic studies suggest that C-H bond cleavage may be the turnover-limiting step.

Synthesis of Atropisomers by Transition-Metal-Catalyzed Asymmetric C-H Functionalization Reactions.

Transition-metal-catalyzed enantioselective C-H functionalization has become a powerful strategy for the formation of C-C or C-X bonds, enabling the highly asymmetric synthesis of a wide range of enantioenriched compounds. Atropisomers are widely found in natural products and pharmaceutically relevant molecules, and have also found applications as privileged frameworks for chiral ligands and catalysts. Thus, research into asymmetric routes for the synthesis of atropisomers has garnered great interest in recent years. In this regard, transition-metal-catalyzed enantioselective C-H functionalization has emerged as an atom-economic and efficient strategy toward their synthesis. In this Perspective, the approaches for the synthesis of atropisomers by transition-metal-catalyzed asymmetric C-H functionalization reactions are summarized. The main focus here is on asymmetric catalysis via Pd, Rh, and Ir complexes, which have been the most frequently utilized catalysts among reported enantioselective C-H functionalization reactions. Finally, we discuss limitations on available protocols and give an outlook on possible future avenues of research.

Recurrent KRAS, KIT and SF3B1 mutations in melanoma of the female genital tract.

BACKGROUND: Malignant melanoma of the female genital tract is relatively uncommon and accounts for 3-7% of all melanoma localizations. This study aimed to identify driver genes in melanoma of the female genital tract with the purpose of enhancing understanding of disease pathogenesis and identifying potential new therapeutic targets to develop effective therapies. METHODS: KIT (CD117) and BRAF expression were detected immunohistochemically. Polymerase Chain Reaction (PCR) and Sanger sequencing techniques were performed to identify the mutational status of BRAF, NRAS, KRAS, NF1, KIT, PDGFRA and SF3B1 on 19 melanomas of the female genital tract, paired with 25 cutaneous melanomas, 18 acral melanomas and 11 melanomas of nasal cavity. RESULTS: Somatic variant analysis identified KRAS (6/19; 32%) as the most commonly mutated gene, followed by KIT (4/19; 21%), SF3B1 (3/19; 16%) and NRAS (1/19; 5%). None of the cases were found to harbor BRAF, NF1 and PDGFRA mutations in melanomas of the female genital tract. However, none of the cases were found to harbor SF3B1 and KIT mutations in cutaneous melanomas, acral melanomas and melanomas of nasal cavity. Recurrent KIT mutations, as well as mutations in the less frequently mutated genes NRAS and SF3B1, were exclusively detected in vulvovaginal melanomas, but not in tumors arising in the cervix. However, recurrent KRAS mutations were detected in similar frequencies in tumors of the vulva, vagina, and cervix. Additionally, recurrent KRAS and KIT mutations occurred predominantly in polygonal and epithelioid cell types of melanoma in the female genital tract. Immunohistochemistry revealed moderate or strong cytoplasmic CD117 expression in 6 of the 19 cases (31.6%). CONCLUSIONS: We observed that gynecologic melanoma harbored distinct mutation rates in the KIT, BRAF, SF3B1, KRAS, and NRAS genes. Our findings support the notion that gynecologic melanoma is a distinct entity from non-gynecologic melanoma, and these findings offer insights into future therapeutic options for these patients.