Development of a Novel, Potent, and Selective Sialyltransferase Inhibitor for Suppressing Cancer Metastasis.

Sialyltransferase-catalyzed membrane protein and lipid glycosylation plays a vital role as one of the most abundant post-translational modifications and diversification reactions in eukaryotes. However, aberrant sialylation has been associated with cancer malignancy and metastasis. Sialyltransferases thus represent emerging targets for the development of small molecule cancer drugs. Herein, we report the inhibitory effects of a recently discovered lithocholic acid derivative FCW393 on sialyltransferase catalytic activity, integrin sialyation, cancer-associated signal transduction, MDA-MB-231 and B16F10 cell migration and invasion, and in in vivo studies, on tumor growth, metastasis, and angiogenesis. FCW393 showed effective and selective inhibition of the sialyltransferases ST6GAL1 (IC50 = 7.8 µM) and ST3GAL3 (IC50 = 9.45 µM) relative to ST3GAL1 (IC50 > 400 µM) and ST8SIA4 (IC50 > 100 µM). FCW393 reduced integrin sialylation in breast cancer and melanoma cells dose-dependently and downregulated proteins associated with the integrin-regulated FAK/paxillin and GEF/Rho/ROCK pathways, and with the VEGF-regulated Akt/NFκB/HIF-1α pathway. FCW393 inhibited cell migration (IC50 = 2.6 µM) and invasion in in vitro experiments, and in in vivo studies of tumor-bearing mice, FCW393 reduced tumor size, angiogenesis, and metastatic potential. Based on its demonstrated selectivity, cell permeability, relatively low cytotoxicity (IC50 = 55 µM), and high efficacy, FCW393 shows promising potential as a small molecule experimental tool compound and a lead for further development of a novel cancer therapeutic.

Nicotine reduces social dominance and neutralizes experience-dependent effects during social conflicts in zebrafish (Danio rerio).

Nicotine, a psychoactive pollutant, binds to nicotinic acetylcholine receptors and disrupts the cholinergic modulation and reward systems of the brain, leading to attention deficit, memory loss, and addiction. However, whether nicotine affects social behaviors remains unknown. We assessed the effects of nicotine on the fighting behavior of zebrafish. Adult zebrafish treated with 5 µM nicotine were used in dyadic fighting tests with size-matched control siblings. The results indicate that nicotine treatment not only significantly reduced the likelihood of winning but also impaired the winner-loser effects (winner and loser fish did not show higher winning and losing tendencies in the second fight, respectively, after treatment.) Nicotine led to a considerable increase in c-fos-positive signals in the interpeduncular nucleus (IPN) of the brain, indicating that nicotine induces neural activity in the habenula (Hb)-IPN circuit. We used transgenic fish in which the Hb-IPN circuit was silenced to verify whether nicotine impaired the winner-loser effect through the Hb-IPN pathway. Nicotine-treated fish in which the medial part of the dorsal Hb was silenced did not have a higher winning rate, and nicotine-treated fish in which the lateral part of the dorsal Hb was silenced did not have a higher loss rate. This finding suggests that nicotine impairs the winner-loser effect by modulating the Hb-IPN circuit. Therefore, in these zebrafish, nicotine exposure impaired social dominance and neutralized experience-dependent effects in social conflicts, and it may thereby disturb the social hierarchy and population stability of such fish.

Targeting androgen receptor and the variants by an orally bioavailable Proteolysis Targeting Chimeras compound in castration resistant prostate cancer.

BACKGROUND: Despite the advent of improved therapeutic options for advanced prostate cancer, the durability of clinical benefits is limited due to inevitable development of resistance. By constitutively sustaining androgen receptor (AR) signaling, expression of ligand-binding domain truncated AR variants (AR-V(ΔLBD)) accounts for the major mechanism underlying the resistance to anti-androgen drugs. Strategies to target AR and its LBD truncated variants are needed to prevent the emergence or overcome drug resistance. METHODS: We utilize Proteolysis Targeting Chimeras (PROTAC) technology to achieve induced degradation of both full-length AR (AR-FL) and AR-V(ΔLBD) proteins. In the ITRI-PROTAC design, an AR N-terminal domain (NTD) binding moiety is appended to von-Hippel-Lindau (VHL) or Cereblon (CRBN) E3 ligase binding ligand with linker. FINDINGS: In vitro studies demonstrate that ITRI-PROTAC compounds mechanistically degrade AR-FL and AR-V(ΔLBD) proteins via ubiquitin-proteasome system, leading to impaired AR transactivation on target gene expression, and inhibited cell proliferation accompanied by apoptosis activation. The compounds also significantly inhibit enzalutamide-resistant growth of castration resistant prostate cancer (CRPC) cells. In castration-, enzalutamide-resistant CWR22Rv1 xenograft model without hormone ablation, ITRI-90 displays a pharmacokinetic profile with decent oral bioavailability and strong antitumor efficacy. INTERPRETATION: AR NTD that governs the transcriptional activities of all active variants has been considered attractive therapeutic target to block AR signaling in prostate cancer cells. We demonstrated that utilizing PROTAC for induced AR protein degradation via NTD represents an efficient alternative therapeutic strategy for CRPC to overcome anti-androgen resistance. FUNDING: The funding detail can be found in the Acknowledgements section.

Fish Behavior as a Neural Proxy to Reveal Physiological States.

Behaviors are the integrative outcomes of the nervous system, which senses and responds to the internal physiological status and external stimuli. Teleosts are aquatic organisms which are more easily affected by the surrounding environment compared to terrestrial animals. To date, behavioral tests have been widely used to assess potential environmental risks using fish as model animals. In this review, we summarized recent studies regarding the effects of internal and external stimuli on fish behaviors. We concluded that behaviors reflect environmental and physiological changes, which have possible implications for environmental and physiological assessments.

The Intraocular Pressure Lowering Effect of a Dual Kinase Inhibitor (ITRI-E-(S)4046) in Ocular Hypertensive Animal Models.

Purpose: The purpose of this study was to develop a preclinical compound, ITRI-E-(S)4046, a dual synergistic inhibitor of myosin light chain kinase 4 (MYLK4) and Rho-related protein kinase (ROCK), for reducing intraocular pressure (IOP). Methods: ITRI-E-(S)4046 is an amino-pyrazole derivative with physical and chemical properties suitable for ophthalmic formulation. In vitro kinase inhibition was evaluated using the Kinase-Glo Luminescent Kinase Assays. A comprehensive kinase selectivity analysis of ITRI-E-(S)4046 was performed using the KINOMEscan assay from DiscoverRx. The IOP reduction and tolerability of ITRI-E-(S)4046 were assessed in ocular normotensive rabbits, ocular normotensive non-human primates, and ocular hypertensive rabbits. In vivo studies were conducted to assess drug concentrations in ocular tissue. The adverse ocular effects of rabbit eyes were evaluated following the OECD405 guidelines. Results: ITRI-E-(S)4046 showed highly selective kinase inhibitory activity against ROCK1/2, MYLK4, and mitogen-activated protein kinase kinase kinase 19 (MAP3K19), with high specificity against protein kinase A, G, and C families. In ocular normotensive rabbits and non-human primates, the mean IOP reductions of 0.1% ITRI-E-(S)4046 eye drops were 29.8% and 28.5%, respectively. In hypertonic saline-induced and magnetic beads-induced ocular hypertensive rabbits, the mean IOP reductions of ITRI-E-(S)4046 0.1% eye drops were 46.9% and 22.0%, respectively. ITRI-E-(S)4046 was well tolerated with only temporary and minor signs of hyperemia. Conclusions: ITRI-E-(S)4046 is a novel type of highly specific ROCK1/2 and MYLK4 inhibitor that can reduce IOP in normotensive and hypertensive animal models. It has the potential to become an effective and well-tolerated treatment for glaucoma.

Sialyltransferase Inhibitors for the Treatment of Cancer Metastasis: Current Challenges and Future Perspectives.

Potent, cell-permeable, and subtype-selective sialyltransferase inhibitors represent an attractive family of substances that can potentially be used for the clinical treatment of cancer metastasis. These substances operate by specifically inhibiting sialyltransferase-mediated hypersialylation of cell surface glycoproteins or glycolipids, which then blocks the sialic acid recognition pathway and leads to deterioration of cell motility and invasion. A vast amount of evidence for the in vitro and in vivo effects of sialyltransferase inhibition or knockdown on tumor progression and tumor cell metastasis or colonization has been accumulated over the past decades. In this regard, this review comprehensively discusses the results of studies that have led to the recent discovery and development of sialyltransferase inhibitors, their potential biomedical applications in the treatment of cancer metastasis, and their current limitations and future opportunities.

Sialyltransferase Inhibitors Suppress Breast Cancer Metastasis.

We report the synthesis and evaluation of a series of cell-permeable and N- versus O-selective sialyltransferase inhibitors. Inhibitor design entailed the functionalization of lithocholic acid at C(3) and at the cyclopentane ring side chain. Among the series, FCW34 and FCW66 were shown to inhibit MDA-MB-231 cell migration as effectively as ST3GALIII-gene knockdown did. FCW34 was shown to inhibit tumor growth, reduce angiogenesis, and delay cancer cell metastasis in animal models. Furthermore, FCW34 inhibited vessel development and suppressed angiogenic activity in transgenic zebrafish models. Our results provide clear evidence that FCW34-induced sialyltransferase inhibition reduces cancer cell metastasis by decreasing N-glycan sialylation, thus altering the regulation of talin/integrin/FAK/paxillin and integrin/NFκB signaling pathways.

Exposure to silver impairs learning and social behaviors in adult zebrafish.

Silver and silver nanoparticles are used in several consumer products, particularly sterilizing agents. Ag+ released from the particles causes physiological damages of aquatic organisms. However, the effects of silver on neural and behavioral functions of fish remain unclear. Here, we used zebrafish as a model to investigate the impacts of silver on social, learning and memory behaviors in teleost. Adult zebrafish showed mortality rates of 12.875% and 100% on 72 h exposure to 30 and ≥ 50 ppb of silver nitrate, respectively. Silver accumulation in the brain increased on exposure to 10 and 30 ppb of AgNO3. The physical fitness of the zebrafish, measured by novel tank diving test and swimming performance, decreased after 72 h incubation in 30 ppb of AgNO3. Exposure to 10 ppb of AgNO3 impaired social preference, social recognition, learning, and memory, but did not affect anxiety level, aggressiveness, and shoaling behavior. In situ hybridization of c-fos mRNA showed that AgNO3 treatment decreased neural activity in the brain areas crucial for learning, memory, and social behaviors, including the medial and dorsal zones of the dorsal telencephalic area. In conclusion, 72 h exposure to AgNO3 in a sublethal level impaired learning and social behaviors, indicating neurotoxicity in adult zebrafish.

Analysis of COVID-19 prevention and treatment in Taiwan.

Coronavirus disease 2019 (COVID-19) has been spreading worldwide with a mind-boggling speed. According to a statement from World Health Organization (WHO), COVID-19 has infected more than six billions people and caused more than one and half million passing in the world. Based on previous experience with SARS, the Taiwanese government had decided to block viral transmission during its early stages. This review sums up the clinical characteristics, Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) viral infection process, diagnostic methods, preventive strategy, and the executive proportions of COVID-19, as well as the name-based mask distribution system (NBMDS) in Taiwan. We also give a review of the conceivable sub-atomic pharmacologic systems against SARS-CoV-2 specialists and the blend of remdesivir (GS-5734), chloroquine (CQ), and hydroxychloroquine (HCQ). Lastly, we summarized the therapeutic agents against COVID-19 as mentioned by COVID-19 treatment guidelines. In this review, development of novel anti-SARS-CoV-2 viral agents, vaccines for COVID-19 therapy or an effective combination therapy can be expected based on all the information accumulated. Last but not least, we might want to stretch out our best respects to all medical providers in their worldwide battle against COVID-19.

Approaches towards fighting the COVID­19 pandemic (Review).

The coronavirus disease 2019 (COVID­19) outbreak, which has caused >46 millions confirmed infections and >1.2 million coronavirus related deaths, is one of the most devastating worldwide crises in recent years. Infection with COVID­19 results in a fever, dry cough, general fatigue, respiratory symptoms, diarrhoea and a sore throat, similar to those of acute respiratory distress syndrome. The causative agent of COVID­19, SARS­CoV­2, is a novel coronavirus strain. To date, remdesivir has been granted emergency use authorization for use in the management of infection. Additionally, several efficient diagnostic tools are being actively developed, and novel drugs and vaccines are being evaluated for their efficacy as therapeutic agents against COVID­19, or in the prevention of infection. The present review highlights the prevalent clinical manifestations of COVID­19, characterizes the SARS­CoV­2 viral genome sequence and life cycle, highlights the optimal methods for preventing viral transmission, and discusses possible molecular pharmacological mechanisms and approaches in the development of anti­SARS­CoV­2 therapeutic agents. In addition, the use of traditional Chinese medicines for management of COVID­19 is discussed. It is expected that novel anti­viral agents, vaccines or an effective combination therapy for treatment/management of SARS­CoV­2 infection and spread therapy will be developed and implemented in 2021, and we would like to extend our best regards to the frontline health workers across the world in their fight against COVID­19.

Anticancer efficacy of unique pyridine-based tetraindoles.

Results of previous studies demonstrated that the tetraindole, SK228, which has a high lipid but low water solubility, displayed moderate anticancer efficacy in a xenograft model of breast cancer. This finding led to the proposal that new, pyridine based tetraindole (PBT) analogs of SK228, containing tetraindole moieties distributed about central protonated pyridine cores, would have enhanced bioavailabilities and anticancer efficacies. Among the PBTs prepared and subjected to biological studies, 3f (FCW81) was observed to display the highest antiproliferative activity against the two triple negative breast cancer (TNBCs) cell lines, MDA-MB-231 and BT549. In addition, its mode of action was shown to involve G2/M arrest of the cell cycle along with the promotion of increased levels of cyclin B1 and p-chk2 and a decreased level of p-cdc2. DNA damage and induction of apoptosis caused by FCW81 was found to be associated with a decrease in DNA repair. Significantly, FCW81 displays therapeutic efficacy in a xenograft model of human breast cancer by not only serving to inhibit markedly the growth of cancer cells but also to block effectively cancer cell metastasis. Collectively, the results of these studies have led to the identification of novel pyridine-tetraindole based anticancer agents with potential use in TNBC therapy.