Progestogen-driven B7-H4 contributes to onco-fetal immune tolerance.

Immune tolerance mechanisms are shared in cancer and pregnancy. Through cross-analyzing single-cell RNA-sequencing data from multiple human cancer types and the maternal-fetal interface, we found B7-H4 (VTCN1) is an onco-fetal immune tolerance checkpoint. We showed that genetic deficiency of B7-H4 resulted in immune activation and fetal resorption in allogeneic pregnancy models. Analogously, B7-H4 contributed to MPA/DMBA-induced breast cancer progression, accompanied by CD8+ T cell exhaustion. Female hormone screening revealed that progesterone stimulated B7-H4 expression in placental and breast cancer cells. Mechanistically, progesterone receptor (PR) bound to a newly identified -58 kb enhancer, thereby mediating B7-H4 transcription via the PR-P300-BRD4 axis. PR antagonist or BRD4 degrader potentiated immunotherapy in a murine B7-H4+ breast cancer model. Thus, our work unravels a mechanistic and biological connection of a female sex hormone (progesterone) to onco-fetal immune tolerance via B7-H4 and suggests that the PR-P300-BRD4 axis is targetable for treating B7-H4+ cancer.

Complete elimination of estrogen receptor α by PROTAC estrogen receptor α degrader ERD-148 in breast cancer cells.

PURPOSE: Estrogen Receptor α (ERα) is a well-established therapeutic target for Estrogen Receptor (ER)-positive breast cancers. Both Selective Estrogen Receptor Degraders (SERD) and PROTAC ER degraders are synthetic compounds suppressing the ER activity through the degradation of ER. However, the differences between SERD and PROTAC ER degraders are far from clear. METHODS: The effect of PROTAC ER degrader ERD-148 and SERD fulvestrant on protein degradation was evaluated by western blot analysis. The cell proliferation was tested by WST-8 assays and the gene expressions were assessed by gene microarray and real-time RT-PCR analysis after the compound treatment. RESULTS: ERD-148 is a potent and selective PROTAC ERα degrader. It degrades not only unphosphorylated ERα but also the phosphorylated ERα in the cells. In contrast, the SERD fulvestrant showed much-reduced degradation potency on the phosphorylated ERα. The more complete degradation of ERα by ERD-148 translates into a greater maximum cell growth inhibition. However, ERD-148 and fulvestrant share a similar gene regulation profile except for the variation of regulation potency. Further studies indicate that ERD-148 degrades the ERα in fulvestrant-resistant cells. CONCLUSION: PROTAC ER degrader has a different mechanism of action compared to SERD which may be used in treating fulvestrant-resistant cancers.

Molecular phylogenetics of the fresh water sleepers Odontobutis (Gobiiformes: Odontobutidae) and its implications on biogeography of freshwater ichthyofauna of East Asia.

The genus Odontobutis is a group of freshwater fishes endemic to East Asia. Phylogenetic relationships among the Odontobutis species have never been fully tested due to incomplete taxon sampling and that molecular data have not been collected in many Odontobutis species. In the present study, we sampled 51 specimens from all known eight Odontobutis species with two outgroups (Perccottus glenii and Neodontobutis hainanensis). We collected sequence data of 4434 single-copy nuclear coding loci using gene capture and Illumina sequencing. A robust phylogeny of the Odontobutis with many individuals for each species was built, supporting the current taxonomy that all extant Odontobutis species are valid. The two species from Japan (O. hikimius + O. obscurus) formed an independent clade sister to the "continental odontobutids", whereas the species from southern China (O. sinensis + O. haifengensis) separated from the rest species of the genus. Surprisingly species from the lower reaches of the Yangtze River (O. potamophilus) was more closely related to species from the Korean Peninsula and northeastern China than to the middle reaches of the Yangtze River, such that their relationship was ((O. sinensis + O. haifengensis)(O. platycephala + (O. yaluensis + (O. potamophilus + O. interruptus)))). Divergence time among the Odontobutis was estimated using 100 most clock-like loci and three fossil calibration points. The crown group of the Odontobutis was estimated at 9.0 Ma during the late Miocene (5.6-12.7 Ma, 95% HPDs). Ancestral range of the genus was reconstructed using Reconstruct Ancestral States in Phylogenies (RASP) and BioGeoBEARS. The result suggested that the common ancestor of modern Odontobutis probably was distributed in Japan, southern China or the Korean Peninsula. A series of geographical events in East Asia since the late Miocene, such as the opening of the Japan/East Sea, rapid uplift of the Tibetan Plateau and climate change in the northern region of the Yellow River might account for diversification and current distribution pattern of the Odontobutis.

Precise Conformational Control Yielding Highly Potent and Exceptionally Selective BRD4 Degraders with Strong Antitumor Activity.

Starting from a nonselective bromodomain and extraterminal (BET) inhibitor and a cereblon ligand, we have used precise conformational control for the development of two potent and highly selective BRD4 degraders, BD-7148 and BD-9136. These compounds induce rapid degradation of BRD4 protein in cells at concentrations as low as 1 nM and demonstrate ≥1000-fold degradation selectivity over BRD2 or BRD3 protein. Proteomic analysis of >5700 proteins confirmed their highly selective BRD4 degradation. A single dose of BD-9136 selectively and effectively depletes BRD4 protein in tumor tissues for >48 h. BD-9136 effectively inhibits tumor growth without adverse effects on mice and is more efficacious than the corresponding pan BET inhibitor. This study suggests selective degradation of BRD4 as a strategy for the treatment of human cancers and demonstrates a strategy for the design of highly selective PROTAC degraders.

Microdousamblyrhynchos sp. nov., a new member of the small-toothed sleepers (Teleostei, Gobiiformes, Odontobutidae) from Guangxi, southern China.

Microdousamblyrhynchos, a new species, the second one in the genus, from the family Odontobutidae, is described from the Hongshui River, in the upper reaches of the Xijiang River of the Pearl River drainage, Baise City, Guangxi Zhuang Autonomous Region, southern China. This species is distinguished from its only congener, M.chalmersi, by the blunt snout (vs. pointed); mean snout length/head length ratio 0.27 (vs. 0.3); eye not extending outward (vs. protruding); mean interorbital width/head length ratio 0.25 (vs. 0.11). Additionally, the results of molecular phylogenetic analysis confirmed that M.amblyrhynchossp. nov. is distinct from its sister species, M.chalmersi.

Correction to: Targeted degradation of activating estrogen receptor α ligand-binding domain mutations in human breast cancer.

In the original publication of the article, the spelling of the sixth author's given name was incorrect. The corrected author name should read as "Wadie David". The original article has been corrected.

Targeted degradation of activating estrogen receptor α ligand-binding domain mutations in human breast cancer.

PURPOSE: Studies have identified several estrogen receptor α (ERα) ligand-binding domain (LBD) somatic mutations in endocrine therapy resistant, metastatic ER-positive breast cancers. The most common mutations, Tyr537Ser (Y537S) and Asp538Gly (D538G), are detected in ~ 30% of endocrine resistant metastatic breast cancer patients. These ESR1 mutations induce the agonist conformation of ERα, confer an estrogen-independent phenotype, and promote drug resistance to antiestrogens. METHODS: ER-positive, estrogen-dependent MCF-7 cells were engineered to express either the Y537S or D538G mutants using CRISPR knock-in (cY537S and cD538G). These cells were used to screen several estrogen receptor degrader (ERD) compounds synthesized using the Proteolysis Targeting Chimeras (PROTAC) method to induce degradation of ERα via the ubiquitin-proteasome pathway. RESULTS: Wild-type MCF-7 and ERα LBD mutant cells were treated with ERD-148 (10 pM-1 µM) and assayed for cellular proliferation using the PrestoBlue cell viability assay. ERD-148 attenuated ER-dependent growth with IC50 values of 0.8, 10.5, and 6.1 nM in MCF-7, cY537S, and cD538G cells, respectively. Western blot analysis showed that MCF-7 cells treated with 1 nM ERD-148 for 24 h exhibited reduced ERα protein expression as compared to the mutants. The ER-regulated gene, GREB1, demonstrated significant downregulation in parental and mutant cells after 24 h of ERD-148 treatment at 10 nM. Growth of the ER-negative, estrogen-independent MDA-MB-231 breast cancer cells was not inhibited by ERD-148 at the ~ IC90 observed in the ER-positive cells. CONCLUSION: ERD-148 inhibits the growth of ER-positive breast cancer cells via downregulating ERα with comparable potency to Fulvestrant with marginal non-specific toxicity.

Discovery of ERD-308 as a Highly Potent Proteolysis Targeting Chimera (PROTAC) Degrader of Estrogen Receptor (ER).

The estrogen receptor (ER) is a validated target for the treatment of estrogen receptor-positive (ER+) breast cancer. Here, we describe the design, synthesis, and extensive structure-activity relationship (SAR) studies of small-molecule ERα degraders based on the proteolysis targeting chimeras (PROTAC) concept. Our efforts have resulted in the discovery of highly potent and effective PROTAC ER degraders, as exemplified by ERD-308 (32). ERD-308 achieves DC50 (concentration causing 50% of protein degradation) values of 0.17 and 0.43 nM in MCF-7 and T47D ER+ breast cancer cell lines, respectively, and induces >95% of ER degradation at concentrations as low as 5 nM in both cell lines. Significantly, ERD-308 induces more complete ER degradation than fulvestrant, the only approved selective ER degrader (SERD), and is more effective in inhibition of cell proliferation than fulvestrant in MCF-7 cells. Further optimization of ERD-308 may lead to a new therapy for advanced ER+ breast cancer.

Discovery of QCA570 as an Exceptionally Potent and Efficacious Proteolysis Targeting Chimera (PROTAC) Degrader of the Bromodomain and Extra-Terminal (BET) Proteins Capable of Inducing Complete and Durable Tumor Regression.

Proteins of the bromodomain and extra-terminal (BET) family are epigenetics "readers" and promising therapeutic targets for cancer and other human diseases. We describe herein a structure-guided design of [1,4]oxazepines as a new class of BET inhibitors and our subsequent design, synthesis, and evaluation of proteolysis-targeting chimeric (PROTAC) small-molecule BET degraders. Our efforts have led to the discovery of extremely potent BET degraders, exemplified by QCA570, which effectively induces degradation of BET proteins and inhibits cell growth in human acute leukemia cell lines even at low picomolar concentrations. QCA570 achieves complete and durable tumor regression in leukemia xenograft models in mice at well-tolerated dose-schedules. QCA570 is the most potent and efficacious BET degrader reported to date.

Discovery of a Small-Molecule Degrader of Bromodomain and Extra-Terminal (BET) Proteins with Picomolar Cellular Potencies and Capable of Achieving Tumor Regression.

The bromodomain and extra-terminal (BET) family proteins, consisting of BRD2, BRD3, BRD4, and testis-specific BRDT members, are epigenetic "readers" and play a key role in the regulation of gene transcription. BET proteins are considered to be attractive therapeutic targets for cancer and other human diseases. Recently, heterobifunctional small-molecule BET degraders have been designed based upon the proteolysis targeting chimera (PROTAC) concept to induce BET protein degradation. Herein, we present our design, synthesis, and evaluation of a new class of PROTAC BET degraders. One of the most promising compounds, 23, effectively degrades BRD4 protein at concentrations as low as 30 pM in the RS4;11 leukemia cell line, achieves an IC50 value of 51 pM in inhibition of RS4;11 cell growth and induces rapid tumor regression in vivo against RS4;11 xenograft tumors. These data establish that compound 23 (BETd-260/ZBC260) is a highly potent and efficacious BET degrader.

Learning from Natural Nacre: Constructing Layered Polymer Composites with High Thermal Conductivity.

Inspired by the microstructures of naturally layered and highly oriented materials, such as natural nacre, we report a thermally conductive polymer composite that consists of epoxy resin and Al2O3 platelets deposited with silver nanoparticles (AgNPs). Owing to their unique two-dimensional structure, Al2O3 platelets are stacked together via a hot-pressing technique, resulting in a brick-and-mortar structure, which is similar to the one of natural nacre. Moreover, the AgNPs deposited on the surfaces of the Al2O3 platelets act as bridges that link the adjacent Al2O3 platelets due to the reduced melting point of the AgNPs. As a result, the polymer composite with 50 wt % filler achieves a maximum thermal conductivity of 6.71 W m-1 K-1. In addition, the small addition of AgNPs (0.6 wt %) minimally affects the electrical insulation of the composites. Our bioinspired approach will find uses in the design and fabrication of thermally conductive materials for thermal management in modern electronics.

Polymer Composite with Improved Thermal Conductivity by Constructing a Hierarchically Ordered Three-Dimensional Interconnected Network of BN.

In this work, we report a fabrication of epoxy resin/ordered three-dimensional boron nitride (3D-BN) network composites through combination of ice-templating self-assembly and infiltration methods. The polymer composites possess much higher thermal conductivity up to 4.42 W m-1 K-1 at relatively low loading 34 vol % than that of random distribution composites (1.81 W m-1 K-1 for epoxy/random 3D-BN composites, 1.16 W m-1 K-1 for epoxy/random BN composites) and exhibit a high glass transition temperature (178.9-229.2 °C) and dimensional stability (22.7 ppm/K). We attribute the increased thermal conductivity to the unique oriented 3D-BN thermally conducive network, in which the much higher thermal conductivity along the in-plane direction of BN microplatelets is most useful. This study paves the way for thermally conductive polymer composites used as thermal interface materials for next-generation electronic packaging and 3D integration circuits.

Targeted Degradation of BET Proteins in Triple-Negative Breast Cancer.

Triple-negative breast cancers (TNBC) remain clinically challenging with a lack of options for targeted therapy. In this study, we report the development of a second-generation BET protein degrader, BETd-246, which exhibits superior selectivity, potency, and antitumor activity. In human TNBC cells, BETd-246 induced degradation of BET proteins at low nanomolar concentrations within 1 hour of exposure, resulting in robust growth inhibition and apoptosis. BETd-246 was more potent and effective in TNBC cells than its parental BET inhibitor compound BETi-211. RNA-seq analysis revealed predominant downregulation of a large number of genes involved in proliferation and apoptosis in cells treated with BETd-246, as compared with BETi-211 treatment that upregulated and downregulated a similar number of genes. Functional investigations identified the MCL1 gene as a critical downstream effector for BET degraders, which synergized with small-molecule inhibitors of BCL-xL in triggering apoptosis. In multiple murine xenograft models of human breast cancer, BETd-246 and a further optimized analogue BETd-260 effectively depleted BET proteins in tumors and exhibited strong antitumor activities at well-tolerated dosing schedules. Overall, our findings show that targeting BET proteins for degradation represents an effective therapeutic strategy for TNBC treatment. Cancer Res; 77(9); 2476-87. ©2017 AACR.

Interfacial Engineering of Silicon Carbide Nanowire/Cellulose Microcrystal Paper toward High Thermal Conductivity.

Polymer composites with high thermal conductivity have attracted much attention, along with the rapid development of electronic devices toward higher speed and better performance. However, high interfacial thermal resistance between fillers and matrix or between fillers and fillers has been one of the primary bottlenecks for the effective thermal conduction in polymer composites. Herein, we report on engineering interfacial structure of silicon carbide nanowire/cellulose microcrystal paper by generating silver nanostructures. We show that silver nanoparticle-deposited silicon carbide nanowires as fillers can effectively enhance the thermal conductivity of the matrix. The in-plane thermal conductivity of the resultant composite paper reaches as high as 34.0 W/m K, which is one order magnitude higher than that of conventional polymer composites. Fitting the measured thermal conductivity with theoretical models qualitatively demonstrates that silver nanoparticles bring the lower interfacial thermal resistances both at silicon carbide nanowire/cellulose microcrystal and silicon carbide nanowire/silicon carbide nanowire interfaces. This interfacial engineering approach provides a powerful tool for sophisticated fabrication of high-performance thermal-management materials.

Unactivated C(sp(3))-H hydroxylation through palladium catalysis with H2O as the oxygen source.

A novel palladium catalyzed hydroxylation of unactivated aliphatic C(sp(3))-H bonds was successfully developed. Different from conventional methods, water serves as the hydroxyl group source in the reaction. This new reaction demonstrates good reactivity and broad functional group tolerance. The C-H hydroxylated products can be readily transformed into various highly valuable chemicals via known transformations. Based on experimental and theoretical studies, a mechanism involving the Pd(II)/(IV) pathway is proposed for this hydroxylation reaction.

Synthesis of indazoles and azaindazoles by intramolecular aerobic oxidative C-N coupling under transition-metal-free conditions.

A transition-metal-free oxidative C-N coupling method has been developed for the synthesis of 1H-azaindazoles and 1H-indazoles from easily accessible hydrazones. The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions.

Synthesis of tri- and tetrasubstituted pyrazoles via Ru(II) catalysis: intramolecular aerobic oxidative C-N coupling.

An unprecedented ruthenium(II)-catalyzed intramolecular oxidative C-N coupling method has been developed for the facile synthesis of a variety of synthetically challenging tri- and tetrasubstituted pyrazoles. Dioxygen gas is employed as the oxidant in this transformation. The reaction demonstrates excellent reactivity, functional group tolerance, and high yields.

A general and efficient approach to 2H-indazoles and 1H-pyrazoles through copper-catalyzed intramolecular N-N bond formation under mild conditions.

A new efficient copper-catalyzed intramolecular amination reaction has been developed to readily synthesise a wide variety of multi-substituted 2H-indazole and 1H-pyrazole derivatives from easily accessible starting materials under mild conditions. A highly selective ligand for estrogen receptor ß was prepared in three steps by employing this method.