International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function.

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

MYC promotes aggressive growth and metastasis of a WNT-medulloblastoma mouse model.

Medulloblastoma (MB), the most common malignant pediatric brain tumor, comprises four molecularly and clinically distinct subgroups (termed WNT, SHH, Group3, and Group4). Prognosis varies based on genetic and pathological features associated with each molecular subgroup. WNT-MB, considered low-risk, are rarely metastatic and contain activating mutations in CTNNB1; Group3-MB, commonly classified as high-risk, are frequently metastatic and can contain genomic alterations resulting in elevated MYC expression. Here we compare model systems of low-risk WNT-MB and high-risk Group3-MB to identify tumor and microenvironment interactions that could contribute to features associated with prognosis. Compared to Group3-MB, we find that WNT-MB are enriched in gene sets related to extracellular matrix (ECM) regulation and cellular adhesion. Exogenous expression of MycT58A in a murine WNT-MB model significantly accelerates growth and results in metastatic disease. In addition to decreased ECM regulation and cell adhesion pathways, we also identified immune system interactions among the top down-regulated signaling pathways following MycT58A expression. Taken together, our data provides evidence that increased Myc-signaling can promote the growth and metastasis in a murine model of WNT-MB.

Compositional analysis of lignocellulosic biomass: conventional methodologies and future outlook.

The composition and structural properties of lignocellulosic biomass have significant effects on its downstream conversion to fuels, biomaterials, and building-block chemicals. Specifically, the recalcitrance to modification and compositional variability of lignocellulose make it challenging to optimize and control the conditions under which the conversion takes place. Various characterization protocols have been developed over the past 150 years to elucidate the structural properties and compositional patterns that affect the processing of lignocellulose. Early characterization techniques were developed to estimate the relative digestibility and nutritional value of plant material after ingestion by ruminants and humans alike (e.g. dietary fiber). Over the years, these empirical techniques have evolved into statistical approaches that give a broader and more informative analysis of lignocellulose for conversion processes, to the point where an entire compositional and structural analysis of lignocellulosic biomass can be completed in minutes, rather than weeks. The use of modern spectroscopy and chemometric techniques has shown promise as a rapid and cost effective alternative to traditional empirical techniques. This review serves as an overview of the compositional analysis techniques that have been developed for lignocellulosic biomass in an effort to highlight the motivation and migration towards rapid, accurate, and cost-effective data-driven chemometric methods. These rapid analysis techniques can potentially be used to optimize future biorefinery unit operations, where large quantities of lignocellulose are continually processed into products of high value.

Texas Native Plants Yield Compounds with Cytotoxic Activities against Prostate Cancer Cells.

There remains a critical need for more effective therapies for the treatment of late-stage and metastatic prostate cancers. Three Texas native plants yielded three new and three known compounds with antiproliferative and cytotoxic activities against prostate cancer cells with IC50 values in the range of 1.7-35.0 µM. A new sesquiterpene named espadalide (1), isolated from Gochnatia hypoleuca, had low micromolar potency and was highly effective in clonogenic assays. Two known bioactive germacranolides (2 and 3) were additionally isolated from G. hypoleuca. Dalea frutescens yielded two new isoprenylated chalcones, named sanjuanolide (4) and sanjoseolide (5), and the known sesquiterpenediol verbesindiol (6) was isolated from Verbesina virginica. Mechanistic studies showed that 1-4 caused G2/M accumulation and the formation of abnormal mitotic spindles. Tubulin polymerization assays revealed that 4 increased the initial rate of tubulin polymerization, but did not change total tubulin polymer levels, and 1-3 had no effects on tubulin polymerization. Despite its cytotoxic activity, compound 6 did not initiate changes in cell cycle distribution and has a mechanism of action different from the other compounds. This study demonstrates that new compounds with significant biological activities germane to unmet oncological needs can be isolated from Texas native plants.

Melampodium leucanthum, a source of cytotoxic sesquiterpenes with antimitotic activities.

A new tricyclic sesquiterpene, named meleucanthin (1), was isolated from an extract of the leaves and branches of Melampodium leucanthum, along with four known germacranolide sesquiterpene lactones, leucanthin-A (2), leucanthin-B (3), melampodin-A acetate (4), and 3α-hydroxyenhydrin (5). The chemical structure of 1 was elucidated by analysis of 1D and 2D NMR and mass spectrometric data. All compounds exhibited antiproliferative and cytotoxic efficacy against PC-3 and DU 145 prostate cancer cells, as well as HeLa cervical cancer cells, with IC50 values ranging from 0.18 to 9 µM. These compounds were effective in clonogenic assays and displayed high cellular persistence. They were also found to be capable of circumventing P-glycoprotein-mediated drug resistance. Mechanism of action studies showed that 4 caused an accumulation of cells in the G2/M phase of the cell cycle, and 2-5 caused the formation of abnormal mitotic spindles. These results suggest the cytotoxic effects of these germacranolides involve inhibition of mitotic spindle function, and it is likely that other mechanisms additionally contribute to cell death. These studies also demonstrate the possibility of isolating new, biologically active compounds from indigenous Texas plants.

Amyrisins A-C, O-prenylated flavonoids from Amyris madrensis.

Three new O-prenylated flavonoids, amyrisins A-C (1-3), were isolated from the leaves and twigs of Amyris madrensis, along with the known compound polygamain (4). The structures of 1-3 were elucidated on the basis of the analysis of spectroscopic data interpretation. Amyrisins B (2) and C (3) showed moderate cytotoxicity against PC-3 and DU 145 prostate cancer cells with IC(50) values of 17.5 and 23 µM, respectively, while amyrisin A (1) did not show any cytotoxicity at the highest concentration tested, 50 µM. Polygamain (4) exhibited potent antiproliferative and microtubule-depolymerizing activities.

PPM1D mutations are oncogenic drivers of de novo diffuse midline glioma formation.

The role of PPM1D mutations in de novo gliomagenesis has not been systematically explored. Here we analyze whole genome sequences of 170 pediatric high-grade gliomas and find that truncating mutations in PPM1D that increase the stability of its phosphatase are clonal driver events in 11% of Diffuse Midline Gliomas (DMGs) and are enriched in primary pontine tumors. Through the development of DMG mouse models, we show that PPM1D mutations potentiate gliomagenesis and that PPM1D phosphatase activity is required for in vivo oncogenesis. Finally, we apply integrative phosphoproteomic and functional genomics assays and find that oncogenic effects of PPM1D truncation converge on regulators of cell cycle, DNA damage response, and p53 pathways, revealing therapeutic vulnerabilities including MDM2 inhibition.

Design and synthesis of novel enhanced water soluble hydroxyethyl analogs of combretastatin A-4.

Thirteen hydroxyethyl- analogs of combretastatin A-4 (CA-4) that contain the 1-(1'-hydroxyethyl)-1-(3",4",5"-trimethoxyphenyl)-2-(substituted phenyl)ethene framework were synthesized. Molecular modeling studies at the DFT level showed that compound 3j adopts a 'twisted' conformation mimicking CA-4. The cytotoxicity of the novel compounds against the growth of murine B16 melanoma and L1210 lymphoma cells in culture was measured using an MTT assay. Three analogs 3f, 3h, and 3j were active. Of these, 3j, which has the same substituents as CA-4 and IC(50) values of 16.1 and 4.1 µM against B16 and L1210 cells, respectively, was selected for further biological evaluation. The activity of 3j was verified by the NCI 60 cell line screen. Compound 3j causes microtubule depolymerization in A-10 cells with an EC(50) of 21.2 µM. Analog 3j, which has excellent water solubility of 479 µM, had antitumor activity in a syngeneic L1210 murine model.

Acetyl analogs of combretastatin A-4: synthesis and biological studies.

The combretastatins have received significant attention because of their simple chemical structures, excellent antitumor efficacy and novel antivascular mechanisms of action. Herein, we report the synthesis of 20 novel acetyl analogs of CA-4 (1), synthesized from 3,4,5-trimethoxyphenylacetone that comprises the A ring of CA-4 with different aromatic aldehydes as the B ring. Molecular modeling studies indicate that these new compounds possess a 'twisted' conformation similar to CA-4. The new analogs effectively inhibit the growth of human and murine cancer cells. The most potent compounds 6k, 6s and 6t, have IC(50) values in the sub-µM range. Analog 6t has an IC(50) of 182 nM in MDA-MB-435 cells and has advantages over earlier analogs due to its enhanced water solubility (456 µM). This compound initiates microtubule depolymerization with an EC(50) value of 1.8 µM in A-10 cells. In a murine L1210 syngeneic tumor model 6t had antitumor activity and no apparent toxicity.

Generation of diffuse intrinsic pontine glioma mouse models by brainstem-targeted in utero electroporation.

BACKGROUND: Diffuse intrinsic pontine gliomas (DIPGs) are highly lethal childhood brain tumors. Their unique genetic makeup, pathological heterogeneity, and brainstem location all present challenges to treatment. Developing mouse models that accurately reflect each of these distinct features will be critical to advance our understanding of DIPG development, progression, and therapeutic resistance. The aims of this study were to generate new mouse models of DIPG and characterize the role of specific oncogenic combinations in DIPG pathogenesis. METHODS: We used in utero electroporation (IUE) to transfect neural stem cells in the developing brainstem with PiggyBac DNA transposon plasmids. Combinations of platelet-derived growth factor B (PDGFB), PdgfraD842V, or PdgfraWT, combined with dominant negative Trp53 (DNp53) and H3.3K27M expression, induced fully penetrant brainstem gliomas. RESULTS: IUE enabled the targeted transfection of brainstem neural stem cells. PDGFB + DNp53 + H3.3K27M induced the rapid development of grade IV gliomas. PdgfraD842V + DNp53 + H3.3K27M produced slower forming grade III gliomas. PdgfraWT + DNp53 + H3.3K27M produced high- and low-grade gliomas with extended latencies. PDGFB, PdgfraD842V, and PdgfraWT DIPG models display unique histopathological and molecular features found in human DIPGs. H3.3K27M induced both overlapping and unique gene expression changes in PDGFB and PdgfraD842V tumors. Paracrine effects of PDGFB promote disruption of pericyte-endothelial interactions and angiogenesis in PDGFB DIPG mouse models. CONCLUSION: Brainstem-targeted IUE provides a rapid and flexible system to generate diverse DIPG mouse models. Using IUE to investigate mutation and pathohistological heterogeneity of DIPG will provide a valuable tool for future genetic and preclinical studies.

Design, Synthesis, and Characterization of 4-Undecylpiperidine-2-carboxamides as Positive Allosteric Modulators of the Serotonin (5-HT) 5-HT2C Receptor.

An impaired signaling capacity of the serotonin (5-HT) 5-HT2C receptor (5-HT2CR) has been implicated in the neurobehavioral processes that promote relapse vulnerability in cocaine use disorder (CUD). Restoration of the diminished 5-HT2CR signaling through positive allosteric modulation presents a novel therapeutic approach. Several new molecules with the 4-alkylpiperidine-2-carboxamide scaffold were designed, synthesized, and pharmacologically evaluated, leading to the discovery of selective 5-HT2CR positive allosteric modulators (PAMs). Compound 16 (CYD-1-79) potentiated 5-HT-evoked intracellular calcium release in cells stably expressing the human 5-HT2CR but not the 5-HT2AR cells. A topographically distinct allosteric site was identified based on the newly solved 5-HT2CR structure. Compound 16 modulated 5-HT2CR-mediated spontaneous ambulation, partially substituted for the training dose of the 5-HT2CR agonist WAY163909, synergized with a low dose of WAY163909 to substitute fully for the stimulus effects of WAY163909, and attenuated relapse vulnerability as assessed in a rodent self-administration model, indicating its therapeutic promise for CUD.

Synthesis and Structure-Activity Relationships of Tool Compounds Based on WAY163909, a 5-HT2C Receptor Agonist.

The development of probe molecules that can be used to investigate G protein-coupled receptor (GPCR) pharmacology, trafficking, and relationship with other GPCRs is an important and growing area of research. Here, we report the synthesis of analogues of the known selective serotonin (5-HT) 5-HT2C receptor (5-HT2CR) agonist WAY163909 which were designed to allow for the attachment of a second ligand, signaling or reporter molecules, as well as immobilization agents to the parent molecule with the maintenance of agonist activity. This goal was accomplished by the synthesis of novel molecules in which sites a-d were modified and resulting compounds were analyzed pharmacologically in vitro.