Human anterior thalamic stimulation evoked cortical potentials align with intrinsic functional connectivity.

Characterizing human thalamocortical network is fundamental for understanding a vast array of human behaviors since the thalamus plays a central role in cortico-subcortical communication. Over the past few decades, advances in functional magnetic resonance imaging have allowed for spatial mapping of intrinsic resting-state functional connectivity (RSFC) between both cortical regions and in cortico-subcortical networks. Despite these advances, identifying the electrophysiological basis of human thalamocortical network architecture remains challenging. By leveraging stereoelectroencephalography electrodes temporarily implanted into distributed cortical regions and the anterior nucleus of the thalamus (ANT) of 10 patients with refractory focal epilepsy, we tested whether ANT stimulation evoked cortical potentials align with RSFC from the stimulation site, derived from a normative functional connectome (n = 1000). Our study identifies spatial convergence of ANT stimulation evoked cortical potentials and normative RSFC. Other than connections to the Papez circuit, the ANT was found to be closely connected to several distinct higher-order association cortices, including the precuneus, angular gyrus, dorsal lateral prefrontal cortex, and anterior insula. Remarkably, we found that the spatial distribution and magnitude of cortical-evoked responses to single-pulse electrical stimulation of the ANT aligned with the spatial pattern and strength of normative RSFC of the stimulation site. The present study provides electrophysiological evidence that stimulation evoked electrical activity flows along intrinsic brain networks connected on a thalamocortical level.

Symptomatic responses elicited by electrical stimulation of the cingulate cortex: Study of a cohort of epileptic patients and literature review.

Our understanding of cingulate cortex function is limited. As a method for locating the epileptogenic zone, direct electrical cortical stimulation (ECS) provides an opportunity to understand the functional localization of the cingulate cortex. This study aimed to learn more about the function of the cingulate cortex by analyzing a large body of data from our center and by reviewing existing literature on cortical mapping. We retrospectively analyzed the ECS data of 124 patients with drug-resistant epilepsy who had undergone electrode implantation in the cingulate cortex. The standard stimulation parameters included a biphasic pulse and bipolar stimulation at 50 Hz. Furthermore, we reviewed existing studies on cingulate responses elicited by the ECS and compared them with our results. A total of 329 responses were evoked in 276 contacts using ECS. Of these, 196 were physiological functional responses, which included sensory, affective, autonomic, language, visual, vestibular, and motor responses, along with a few other sensations. Sensory, motor, vestibular, and visual responses were concentrated in the cingulate sulcus visual area (CSv). Furthermore, 133 epilepsy-related responses were evoked, most of which were concentrated in the ventral cingulate cortex. No responses were evoked by 498 contacts. Furthermore, the comparison of our ECS results with those reported in 11 comprehensive reviews revealed that the cingulate cortex is involved in complicated functions. The cingulate cortex is involved in sensory, affective, autonomic, language, visual, vestibular, and motor functions. The CSv is an integrating node of sensory, motor, vestibular, and visual systems.

Development and implementation of a distributed data network between an academic institution and state health departments to investigate variation in time to HIV viral suppression in the Deep South.

BACKGROUND: Achieving early and sustained viral suppression (VS) following diagnosis of HIV infection is critical to improving outcomes for persons with HIV (PWH). The Deep South of the United States (US) is a region that is disproportionately impacted by the domestic HIV epidemic. Time to VS, defined as time from diagnosis to initial VS, is substantially longer in the South than other regions of the US. We describe the development and implementation of a distributed data network between an academic institution and state health departments to investigate variation in time to VS in the Deep South. METHODS: Representatives of state health departments, the Centers for Disease Control and Prevention (CDC), and the academic partner met to establish core objectives and procedures at the beginning of the project. Importantly, this project used the CDC-developed Enhanced HIV/AIDS Reporting System (eHARS) through a distributed data network model that maintained the confidentiality and integrity of the data. Software programs to build datasets and calculate time to VS were written by the academic partner and shared with each public health partner. To develop spatial elements of the eHARS data, health departments geocoded residential addresses of each newly diagnosed individual in eHARS between 2012-2019, supported by the academic partner. Health departments conducted all analyses within their own systems. Aggregate results were combined across states using meta-analysis techniques. Additionally, we created a synthetic eHARS data set for code development and testing. RESULTS: The collaborative structure and distributed data network have allowed us to refine the study questions and analytic plans to conduct investigations into variation in time to VS for both research and public health practice. Additionally, a synthetic eHARS data set has been created and is publicly available for researchers and public health practitioners. CONCLUSIONS: These efforts have leveraged the practice expertise and surveillance data within state health departments and the analytic and methodologic expertise of the academic partner. This study could serve as an illustrative example of effective collaboration between academic institutions and public health agencies and provides resources to facilitate future use of the US HIV surveillance system for research and public health practice.

Synthesis of Diverse Pentasubstituted Pyrroles by a Gold(I)-Catalyzed Cascade Rearrangement-Cyclization of Tertiary Enamide.

An efficient Au(I)-catalyzed intramolecular cascade reaction of tertiary enamides tethered an alkynyl group has been developed. The process is composed of a propargyl-claisen rearrangement and 5-exo-dig cyclization. This protocol provided a powerful method for the preparation of a variety of pentasubstituted pyrroles derivatives with excellent functional group tolerance in excellent yields. Scale-up experiment and chemical transformations of products exhibited the versatility of tertiary enamides in organic synthesis again.

Discovery of a new class of valosine containing protein (VCP/P97) inhibitors for the treatment of colorectal cancer.

Colorectal cancer (CRC) is a common digestive tract malignant tumor and is the third cancer-related death worldwide. Valosine containing protein (VCP/p97) is a member of the AAA ATPase family, plays an important role in the ubiquitin-mediated degradation of misfolded proteins. Studies have shown that p97 is overexpressed in colorectal cancer and is a potential therapeutic target. Herein, a series of novel p97 inhibitors were designed, synthesized and biologically assayed. Based on the enzymatic results, structure-activity relationships (SAR) were discussed in detail. Some potent compounds were further evaluated to inhibit the proliferation of CRC cell lines HCT-116. The results showed that some compounds were active against CRC cell lines with IC50 values of less than 1 µM. Among the screened compounds, compound 10 exhibited good microsomal stabilities, pharmacokinetic properties and displayed strong antiproliferative activity against the HCT-116 cell line (0.4 µM). Furthermore, compound 10 exhibited strong in vivo anticancer efficacy in the human CRC (HCT-116) mouse xenograft model.

Role of experimental periodontitis in inducing pulmonary inflammation in mice.

OBJECTIVE: The aim of the study was to explore the potential role of experimental periodontitis in pulmonary inflammation in mice. MATERIALS AND METHODS: Mice were divided into control, ligature-induced periodontitis (L) and ligature plus Porphyromonas gingivalis (P. gingivalis)-induced periodontitis (LPG) groups. Alveolar bone resorption, pulmonary function, lung tissue histology and cytokine expression were examined at 2, 4 and 8 weeks. Then cytokines and neutrophils in the peripheral blood and lung tissue were further assessed at 8 weeks to determine the role of cytokines induced by LPG periodontitis, and the effect of P. gingivalis was evaluated using P. gingivalis-IgG and P. gingivalis gingipain. RESULTS: Alveolar bone resorption was more severe in the L and LPG groups. However, pulmonary inflammation was observed only in the LPG group at 8 weeks when cytokines and neutrophils in the peripheral blood and lung tissue were the most significant elevation, along with higher levels of P. gingivalis-IgG and P. gingivalis gingipain. Cytokine levels were also increased in the gingival tissue, peripheral blood and lung tissue in the L group, accompanied by elevated peripheral blood neutrophils, but not as significantly as that in the LPG group. CONCLUSIONS: LPG periodontitis can trigger pulmonary inflammation over the long term, in which cytokines and P. gingivalis play an important role.

Subthalamic Nucleus Stimulation Modulates Motor Epileptic Activity in Humans.

OBJECTIVE: Pharmaco-refractory focal motor epileptic seizures pose a significant challenge. Deep brain stimulation (DBS) is a recently recognized therapeutic option for the treatment of refractory epilepsy. To identify the specific target for focal motor seizures, we evaluate the modulatory effects of the subthalamic nucleus (STN) stimulation because of the critical role of STN in cortico-subcortical motor processing. METHODS: Seven patients with epilepsy with refractory seizures who underwent chronic stereoelectroencephalography (SEEG) monitoring were studied in presurgical evaluation. Seizure onset zone was hypothesized to be partially involved in the motor areas in 6 patients. For each patient, one electrode was temporally implanted into the STN that was ipsilateral to the seizure onset zone. The cortical-subcortical seizure propagation was systemically evaluated. The simultaneously electrophysiological responses over distributed cortical areas to STN stimulation at varied frequencies were quantitatively assessed. RESULTS: We observed the consistent downstream propagation of seizures from the motor cortex toward the ipsilateral STN and remarkable cortical responses on motor cortex to single-pulse STN stimulation. Furthermore, we showed frequency-dependent upstream modulatory effect of STN stimulation on motor cortex specifically. In contrast to the enhanced effects of low frequency stimulation, high-frequency stimulation of the STN can significantly reduce interictal spikes, high-frequency oscillations over motor cortex disclosing effective connections to the STN. INTERPRETATION: This result showed that the STN is not only engaged in as a propagation network of focal motor seizures but STN stimulation can profoundly modulate the epileptic activity of motor cortex in humans, suggesting a mechanism-based alternative for patients suffering from refractory focal motor seizures. ANN NEUROL 2020;88:283-296.

Discovery of novel pyrimidine molecules containing boronic acid as VCP/p97 Inhibitors.

Valine-containing protein (VCP) is a member of the adenosine triphosphate family involved in a variety of cellular activities. VCP/p97 is capable of maintaining protein homeostasis and mediating the degradation of misfolded polypeptides by the ubiquitin-proteasome system (UPS). In this manuscript, a series of novel p97 inhibitors with pyrimidine as core structure were designed, synthesized and biologically evaluated. Based on the enzymatic results, a detailed structure-activity relationship discussion of the synthesized compounds was carried out. Furthermore, cellular activities of the compounds with enzymatic potency of less than 200 nM were investigated by using A549 and RPMI8226 cell lines. Among the screened inhibitors, compound 17 (IC50, 54.7 nM) showed good enzymatic activity. Investigation of cellular activities with non-small cell lung cancer A549 and multiple myeloma (MM) RPMI8226 further confirmed the potency of 17 with the IC50 values of 2.80 µM and 0.86 µM, respectively. Compound 17 is now being developed as a candidate. Finally, docking studies were carried out to explore the possible binding mode between the active inhibitor 17 and p97.

Discovery of novel tripeptide propylene oxide proteasome inhibitors for the treatment of multiple myeloma.

The ubiquitin proteasome pathway (UPP) plays a critical role in the maintenance of cell homeostasis and the development of diseases, such as cancer and neurodegenerative disease. A series of novel tripeptide propylene oxide compounds as proteasome inhibitors were designed, synthesized and biologically investigated in this manuscript. The enzymatic activities of final compounds against 20S human proteasome were investigated and structure-activity relationship (SAR) was summarized. Some potent compounds were further evaluated to inhibit the proliferation of multiple myeloma (MM) cancer cell lines RPMI8226 and U266B. The results showed that some compounds were active against MM cancer cell lines with IC50 values of less than 50 nM. The microsomal metabolic stabilities in human, rat and mice species were carried out and the results showed that compounds 30 and 31 were stable enough to be in vivo investigated. The in vivo pharmacokinetic results showed that compounds 30 and 31 had acceptable biological parameters for both ig and iv administrations. In vivo antitumor activities of compounds 30 and 31 with the doses of 100 mg/kg and 50 mg/kg BIW were performed by using RPMI8226 xenograft nude mouse model. Toxicities of compounds 30 and 31 were not observed during the experiment and dose dependent effect was obvious and the tumor volume was greatly inhibited.

Functional characteristics of the human primary somatosensory cortex: An electrostimulation study.

The common knowledge of the functional organization of the human primary somatosensory cortex (S1) had been primarily established by Penfield who electrically stimulated the exposed surface [referred as Brodmann area (BA)1] of S1 under neurosurgical conditions. Nevertheless, the functional information regarding the deep surface (BA 2 and 3) of S1 is poorly understood. We retrospectively analyzed all the clinical manifestations induced by extra-operative cortical electrical stimulation (ES) in 33 patients with medically intractable epilepsy who underwent stereo-electroencephalography (SEEG) monitoring for presurgical assessment. Demographic and clinical data were gathered and evaluated to delineate the determinants of the occurrence of positive responses, types of responses, and size of body regions involved. The stimulation of 244 sites in S1 yielded 198 positive sites (81.1%), most of which were located in the sulcal cortex. In multivariable analyses, no clinical or demographic factors predicted the occurrence of responses or their threshold levels. The size of body region involved in the responses had ordinal association with the stimulated BA sites (p < 0.001). Various types of responses elicited from the S1 were documented and classified, and the predictors of those responses were also assessed. Our analysis revealed the functional characteristics of the entire S1 and proved the multiplicity of functions of S1.

Clinical application of intraoperative trial-free online-based language mapping for patients with refractory epilepsy.

OBJECTIVE: The objective of the study was to develop and clinically test a trial-free online-based language mapping method for localizing the eloquent cortex easily in epilepsy operation. METHODS: Nine patients with refractory epilepsy were included in this study according to the results of preoperative evaluation for their epileptogenic zones (EZs) located adjacent to the eloquent cortex. When patients were awakened up from general anesthesia during operation, the trial-free online-based language-mapping paradigm was performed. All positive points marked on the cortex in each test were labeled and superimposed together as the result of functional mapping for each patient. The eloquent cortex was mapped according to the results obtained both from the intraoperative trial-free task localization method and the traditional electrical cortical stimulation (ECS). RESULTS: All patients completed this paradigms twice within 10 min. Based on the results of mapping, the EZs were tried to fully resected on the premise of preserving the mapped eloquent cortex as much as possible. The postoperative follow-up showed the outcome of Engel I in six patients and Engel II in three patients, whereas only two patients had aphemia after surgery and recovered within one week and three months, respectively. SIGNIFICANCE: The intraoperative trial-free online-based language mapping method was primarily identified to be safe and effective. This novel method seems to be promising and worthy of improvement.

Multiple ictal onset patterns underlie seizure generation in seizure-free patients with temporal lobe epilepsy surgery: an SEEG study.

PURPOSE: Seizure originates from different pathological substrate; however, the same pathologies may have distinct mechanisms underlying seizure generation. We aimed to improve the understanding of such mechanisms in patients with temporal lobe epilepsy (TLE) by investigating the stereoelectroencephalography (SEEG) ictal onset patterns (IOPs). METHODS: We analyzed data from a cohort of 19 consecutive patients explored by SEEG and had 1-3-year seizure-freedom following temporal lobe resection. RESULTS: Six IOPs were identified. They were low voltage fast activity (LVFA) (36.5%), rhythmic spikes or spike-waves at low frequency and with high amplitude (34.1%), runs of spikes (10.6%), rhythmic sharp waves (8.2%), low frequency high amplitude repetitive spiking (LFRS) (7.1%), and delta activity (3.5%). All six patterns were found in patients with mesial temporal onset and only two patterns were found in patients with temporal neocortical onset. The most prevalent patterns for patients with mesial temporal onset were rhythmic spikes or spike-waves, followed by LVFA with a mean discharge rate 74 Hz. For patients with temporal neocortical onset, the most prevalent IOP pattern was LVFA with a mean discharge rate 35 Hz, followed by runs of spikes. Compared with Lateral TLE (LTLE), the duration between the onset of the IOPs to the onset of the symptom was longer for patients with MTLE (Mesial TLE) (MTLE:55.7 ± 50.6 s vs LTLE:19.5 ± 16.4 s). CONCLUSION: Multiple IOPs underlie seizure generation in patients with TLE. However, the mesial and lateral temporal lobes share distinct IOPs.

Angiotensin II for the Treatment of Vasodilatory Shock.

BACKGROUND: Vasodilatory shock that does not respond to high-dose vasopressors is associated with high mortality. We investigated the effectiveness of angiotensin II for the treatment of patients with this condition. METHODS: We randomly assigned patients with vasodilatory shock who were receiving more than 0.2 µg of norepinephrine per kilogram of body weight per minute or the equivalent dose of another vasopressor to receive infusions of either angiotensin II or placebo. The primary end point was a response with respect to mean arterial pressure at hour 3 after the start of infusion, with response defined as an increase from baseline of at least 10 mm Hg or an increase to at least 75 mm Hg, without an increase in the dose of background vasopressors. RESULTS: A total of 344 patients were assigned to one of the two regimens; 321 received a study intervention (163 received angiotensin II, and 158 received placebo) and were included in the analysis. The primary end point was reached by more patients in the angiotensin II group (114 of 163 patients, 69.9%) than in the placebo group (37 of 158 patients, 23.4%) (odds ratio, 7.95; 95% confidence interval [CI], 4.76 to 13.3; P<0.001). At 48 hours, the mean improvement in the cardiovascular Sequential Organ Failure Assessment (SOFA) score (scores range from 0 to 4, with higher scores indicating more severe dysfunction) was greater in the angiotensin II group than in the placebo group (-1.75 vs. -1.28, P=0.01). Serious adverse events were reported in 60.7% of the patients in the angiotensin II group and in 67.1% in the placebo group. Death by day 28 occurred in 75 of 163 patients (46%) in the angiotensin II group and in 85 of 158 patients (54%) in the placebo group (hazard ratio, 0.78; 95% CI, 0.57 to 1.07; P=0.12). CONCLUSIONS: Angiotensin II effectively increased blood pressure in patients with vasodilatory shock that did not respond to high doses of conventional vasopressors. (Funded by La Jolla Pharmaceutical Company; ATHOS-3 ClinicalTrials.gov number, NCT02338843 .).

Amygdalar and hippocampal beta rhythm synchrony during human fear memory retrieval.

BACKGROUND: Fear, as one of the basic emotions, is crucial in helping humans to perceive hazards and adapt to social activities. Clinically, fear memory is also involved in a wide spectrum of psychiatric disorders. A better understanding of the neural mechanisms of fear thereby has both neuroscientific and clinical significance. In recent years, data from animal models have demonstrated the key role of the amygdala-hippocampal circuit in the development of fear. However, the neural processing of fear memory remains unclear in humans, which is mainly due to the limitation of indirect measure of neural activity. METHODS: Herein, we investigated fear memory by direct intracranial recordings from 8 intractable epilepsy patients with depth electrodes in both the hippocampus and ipsilateral amygdala. All the patients were subjected to a well-established Pavlovian fear memory paradigm consisted of the familiarization task, conditioning task, and retrieval task, respectively. Simultaneous local field potentials from the hippocampus and amygdala were recorded during different stages. The oscillatory activities from the amygdala and hippocampus were analyzed during fear memory retrieval compared with neutral stages. RESULTS: Consistent with previous rodent studies, our results showed that the amygdala was involved in fear memory retrieval rather than neutral memory retrieval, while the hippocampus was involved both in fear memory retrieval and neutral memory retrieval. In particular, we found that there was an enhanced synchronized activity between the amygdala and hippocampus at beta frequencies (14-30 Hz), which suggested that enhanced synchronized activity at beta frequencies between the amygdala and hippocampus play a pivotal role during retrieval of fear memory in human. CONCLUSIONS: Thus, our observation that the amygdala-hippocampal system contributing to fear memory retrieval in human with frequency-depended specificity has provided new insights into the mechanism of fear and have potential clinical relevance.

[Quality evaluation methods for standard decoction of Nelumbinis Folium].

The quality evaluation method for standard decoction of Chinese herbal slices is the basis for the quality evaluation of granules and preparations of classical formula(decoction)of traditional Chinese medicine. This study aimed to establish a method for the determination of quercetin-3-O-glucuronic acid in Nelumbinis Folium(NF)and its standard decoction, so as to provide reference for the quality control of NF and its standard decoction. Fifteen batches of representative NF were collected to prepare standard decoction, and the parameters of dry extract rate, transfer rate of index component, and pH value were calculated. HPLC was used to establish the content determination method for quercetin-3-O-glucuronic acid in NF and its standard decoction. The concentration range of quercetin-3-O-glucuronic acid in the standard decoction of NF was 1.09-3.06 g·L~(-1), while the concentration range of nuciferine was 0.01-0.17 g·L~(-1). The average extraction rate of NF standard decoction was(14.4±2.6)%, the average transfer rate of quercetin-3-O-glucuronic acid was(70.7±18.6)%, and the average transfer rate of nuciferine was(9.6±5.4)%. Compared with Nuciferine, quercetin-3-O-glucuronic acid had a high content and stable transfer rate in standard decoction, and was recommended to be the quality control marker for NF and its standard decoction. This paper establishes a quality evaluation method for NF standard decoction, and can provide reference for the quality control of all preparations derived from NF and its decoction.

Oxygen- and Nitrogen-Embedded Zigzag Hydrocarbon Belts.

Despite the aesthetically appealing structures and tantalizing physical and chemical properties, zigzag hydrocarbon belts and their heteroatom-embedded analogues remain challenging synthetic targets. We report herein the synthesis of diverse O/N-doped zigzag hydrocarbon belts based on selective bridging of the fjords of resorcin[4]arene derivatives through intramolecular SN Ar and palladium-catalyzed intermolecular C-N bond formation reactions. Preorganized conformations of mono-macrocyclic, half-belt and quasi-belt compounds were revealed to facilitate cyclization reactions to construct heteroatom-linked octahydrobelt[8]arenes. The acquired products had strained square-prism-shaped belt structures in which all six-membered heterocyclic rings adopted an unusual boat conformation with equatorially configured alkyl groups. The unprecedented heteroatom-bearing belts also exhibited different photophysical and redox properties to those of octahydrobelt[8]arene analogues.

Toward Anion-π Interactions Directed Self-Assembly with Predesigned Dual Macrocyclic Receptors and Dianions.

Realizing anion-π interaction induced self-assembly with charge-neutral π receptors as building components is extremely challenging. We designed and synthesized a series of bisoxacalix[2]arene[2]triazines 7-11 in which two macrocyclic motifs are linked in diverse branching angle and rigidity. Crystal structures showed the use of rigid linkers is able to control the orientation of the two macrocyclic cavities. The interplay between the two cavities was revealed by binding studies of 8-11 with chloride in solution. Whereas 180°- and 120°-branched hosts 8 and 9 possess dual complexation ability, 60°-branched and flexibly linked hosts 10 and 11 only form 1:1 complex with chloride. Association and self-assembly of these bismacrocyclic building units with dianionic naphthalene-1,5-disulfonate were systematically investigated. The formation of oligomeric self-assemblies and large aggregates in solution was suggested by 1H NMR titrations, concentration- and temperature-variable 1H NMR, diffusion-ordered spectroscopy (DOSY), ESI-MS, and dynamic light scattering (DLS). The anion-π induced long-distance self-assembly with coherent particle formation was revealed by SEM, TEM, cryo-TEM, and AFM techniques. The systematic studies allowed us to draw the conclusion that the dianion served to bridge the initial host aggregates through anion-π interactions and was responsible for the coherent particle formation. The cavity orientation of the bismacrocycle components was found to have a significant influence on the coherent particle morphology.

Anion-π-Directed Self-Assembly between Di- and Trisulfonates and a Rigid Molecular Cage with Three Electron-Deficient V-Clefts.

Anion-π-directed self-assembly between a series of di- and trisulfonate anions and a rigid molecular cage 1 was presented. The self-assembly study was established on a combination of X-ray crystallography, NMR, mass spectrometry (MS), and scanning electron microscopy (SEM) techniques. As revealed in the crystal structures, the cage provided two V-shaped electron-deficient clefts to accommodate sulfonate groups through anion-π interactions. Depending on their structure, the series of anions showed different intermolecular interaction details with the cage and led to the formation of diverse self-assembly motifs. For 1,2-ethanedisulfonate (EDS2-), 1,3-propanedisulfonate (PDS2-), and 1,4-butanedisulfonate (BDS2-), very similar and uniform 2D ladder-like self-assemblies were formed. For 1,6-hexanedisulfonate (HDS2-) with a longer alkyl chain, a helical chain assembly was formed, while 1,3,5-tris(4-sulfophenyl)benzene (TSPB3-) led to a 3D frame structure. In solution, NMR titrations suggested that the cage can complex these anions, with association constants falling in range of 5-114 M-1. NMR spectra recorded at variable concentrations and temperatures and electrospray ionization MS further confirmed self-assembly formation. The morphologies of the diverse self-assemblies formed between the cage and sulfonates were revealed by SEM. This study, hence, provides evidence that anion-π interactions can play decisive roles in self-assembly.

Discovery of a novel dipeptidyl boronic acid proteasome inhibitor for the treatment of multiple myeloma and triple-negative breast cancer.

A series of novel dipeptidyl boronic acid compounds were designed, synthesized and biologically investigated for the inhibition of the ß5 subunit of 20S proteasome and several compounds showed high activities with IC50 values of less than 10 nM. Some of these compounds potently inhibited the multiple myeloma (MM) cancer cell lines with IC50 values of less than 10 nM. It was reported that the inhibition of both ß2 and ß5 subunits strongly increased the cytotoxicity of proteasome inhibitors in solid tumor cells, so some of the compounds were evaluated for the inhibition of the ß2 subunit and the solid tumor triple-negative breast cancer cell line MDA-MB-231. The results showed that three compounds were active for both the ß2 subunit and the triple-negative breast cancer cell line MDA-MB-231. The in vivo pharmacokinetic results showed that compound 8t had good biological parameters for both ig and iv administrations. An in vivo pharmacodynamic experiment showed that compound 8t inhibited the ß5 subunit in whole blood more greatly than the marketed MLN9708 with the same dose at different time periods. A pathological analysis indicated that the injection of compound 8t in the tumor of a triple-negative breast cancer xenograft mice model led to tumor cell necrosis, nucleus condensation, deep staining, cell fragmentation, dissolution and neutrophil infiltration compared with the control group. The data in hand showed that compound 8t might be an effective candidate for the treatment of both MM and triple-negative breast cancer.

Preparation and biological evaluation of soluble tetrapeptide epoxyketone proteasome inhibitors.

A series of novel tetrapeptidyl epoxyketone inhibitors of 20S proteasome was designed and synthesized. To fully understand the SAR, various groups at R1, R2, R3, R4 and R5 positions, including aromatic and aliphatic substituents were designed, synthesized and biologically assayed. Based on the enzymatic results, seven compounds were selected to evaluate their cellular activities and soluble compound 36 showed strong potency against human multiple myeloma (MM) cell lines. Microsomal stability results indicated that compound 36 was more stable in mice, rat and human microsomes than marketed carfilzomib. The in vivo activities of this compound were evaluated with the xenograft mice models of MM cell lines ARH77 and RPMI-8226 with luciferase expression and the T/C value of the two models were 49.5% and 37.6%, respectively. To evaluate the potential cardiovascular toxicity, inhibition of hERG ion channel in HEK293 cells by compound 36 and carfilzomib was carried out. The results indicated that 36 had no binding affinity for the hERG ion channel while carfilzomib could bind it with IC50 of 92.1 µM.