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Proteolysis targeting chimera (PROTAC) technology represents a groundbreaking development in drug discovery, leveraging the ubiquitin‒proteasome system to specifically degrade proteins responsible for the disease. PROTAC is characterized by its unique heterobifunctional structure, which comprises two functional domains connected by a linker. The linker plays a pivotal role in determining PROTAC's biodegradative efficacy. Advanced and rationally designed functional linkers for PROTAC are under development. Nonetheless, the correlation between linker characteristics and PROTAC efficacy remains under-investigated. Consequently, this study will present a multidisciplinary analysis of PROTAC linkers and their impact on efficacy, thereby guiding the rational design of linkers. We will primarily discuss the structural types and characteristics of PROTAC linkers, and the optimization strategies used for their rational design. Furthermore, we will discuss how factors like linker length, group type, flexibility, and linkage site affect the biodegradation efficiency of PROTACs. We believe that this work will contribute towards the advancement of rational linker design in the PROTAC research area.

Multiwalled carbon nanotubes (MWCNTs) are at the forefront of nanotechnology-based advancements in cancer therapy, particularly in the field of targeted drug delivery. The nanotubes are characterized by their concentric graphene layers, which give them outstanding structural strength. They can deliver substantial doses of therapeutic agents, potentially reducing treatment frequency and improving patient compliance. MWCNTs’ diminutive size and modifiable surface enable them to have a high drug loading capacity and penetrate biological barriers. As a result of the extensive research on these nanomaterials, they have been studied extensively as synthetic and chemically functionalized molecules, which can be combined with various ligands (such as folic acid, antibodies, peptides, mannose, galactose, polymers) and linkers, and to deliver anticancer drugs, including but not limited to paclitaxel, docetaxel, cisplatin, doxorubicin, tamoxifen, methotrexate, quercetin and others, to cancer cells. This functionalization facilitates selective targeting of cancer cells, as these ligands bind to specific receptors overexpressed in tumor cells. By sparing non-cancerous cells and delivering the therapeutic payload precisely to cancer cells, this therapeutic payload delivery ability reduces chemotherapy systemic toxicity. There is great potential for MWCNTs to be used as targeted delivery systems for drugs. In this review, we discuss techniques for functionalizing and conjugating MWCNTs to drugs using natural and biomacromolecular linkers, which can bind to the cancer cells’ receptors/biomolecules. Using MWCNTs to administer cancer drugs is a transformative approach to cancer treatment that combines nanotechnology and pharmacotherapy. It is an exciting and rich field of research to explore and optimize MWCNTs for drug delivery purposes, which could result in significant benefits for cancer patients.

A significant proportion of patients who survive coronavirus disease of 2019 (COVID-19) develop a constellation of life-altering symptoms that persist long after the initial infection has resolved. This post-COVID-19 syndrome may result from the development of autoreactive IgG antibodies that cause inflammation and tissue injury. In this commentary, we suggest that efgartigimod, a drug approved for the treatment of generalized myasthenia gravis, be tested for use in patients with post-COVID-19. Efgartigimod is a humanized IgG Fc fragment containing five point mutations that significantly increase affinity for the Fc region of the neonatal crystallizable fragment receptor (FcRn). FcRn is involved in the pathogenesis of autoimmune diseases via the IgG recycling pathway because FcRN binds to autoreactive IgG antibodies and prevents the antibodies from being catabolized. Efgartigimod is a modified immunoglobulin that competitively displaces endogenous IgG from FcRn, thus increasing the level of unbound IgG, which is then catabolized and leads to decreased circulating levels of autoreactive as well as normal IgG. We suggest that efgartigimod be evaluated in a random, double-blind placebo-control trial in adults with post-COVID-19 for at least 2 months. If re-purposing this myasthenia gravis-approved drug for post - COVID-19 is successful, additional bioengineered FcRn antagonists should be tested for efficacy in patients with post-COVID-19.

Abstract Alzheimer’s disease (AD) is a chronic degenerative brain disorder with no clear pathogenesis or effective cure, accounting for 60–80% of cases of dementia. In recent years, the importance of neuroinflammation in the pathogenesis of AD and other neurodegenerative disorders has come into focus. Previously, we made the serendipitous discovery that the widely used drug excipient N,N-dimethylacetamide (DMA) attenuates endotoxin-induced inflammatory responses in vivo. In the current work, we investigate the effect of DMA on neuroinflammation and its mechanism of action in in-vitro and ex-vivo models of AD. We show that DMA significantly suppresses the production of inflammatory mediators, such as reactive oxygen species (ROS), nitric oxide (NO) and various cytokines and chemokines, as well as amyloid-β (Aβ), in cultured microglia and organotypic hippocampal slices induced by lipopolysaccharide (LPS). We also demonstrate that DMA inhibits Aβ-induced inflammation. Finally, we show that the mechanism of DMA’s effect on neuroinflammation is inhibition of the nuclear factor kappa-B (NF-κB) signaling pathway and we show how DMA dismantles the positive feedback loop between NF-κB and Aβ synthesis. Taken together, our findings suggest that DMA, a generally regarded as safe compound that crosses the blood brain barrier, should be further investigated as a potential therapy for Alzheimer’s disease and neuroinflammatory disorders.

Abstract Background Hepatocellular carcinoma (HCC) is a leading cause of cancer‐related death worldwide. The incidence of HCC is affected by genetic and non‐genetic factors. Genetically, mutations in the genes, tumor protein P53 (TP53), catenin beta 1 (CTNNB1), AT‐rich interaction domain 1A (ARIC1A), cyclin dependent kinase inhibitor 2A (CDKN2A), mannose 6‐phosphate (M6P), smooth muscle action against decapentaplegic (SMAD2), retinoblastoma gene (RB1), cyclin D, antigen presenting cells (APC), AXIN1, and E‐cadherin, have been shown to contribute to the occurrence of HCC. Non‐genetic factors, including alcohol consumption, exposure to aflatoxin, age, gender, presence of hepatitis B (HBV), hepatitis C (HCV), and non‐alcoholic fatty liver disease (NAFLD), increase the risk of HCC. Recent Findings The severity of the disease and its occurrence vary based on geographical location. Furthermore, men and minorities have been shown to be disproportionately affected by HCC, compared with women and non‐minorities. Ethnicity has been reported to significantly affect tumorigenesis and clinical outcomes in patients diagnosed with HCC. Generally, differences in gene expression and/or the presence of comorbid medical diseases affect or influence the progression of HCC. Non‐Caucasian HCC patients are significantly more likely to have poorer survival outcomes, compared to their Caucasian counterparts. Finally, there are a number of factors that contribute to the success rate of treatments for HCC. Conclusion Assessment and treatment of HCC must be consistent using evidence‐based guidelines and standardized outcomes, as well as international clinical practice guidelines for global consensus. Standardizing the assessment approach and method will enable comparison and improvement of liver cancer research through collaboration between researchers, healthcare providers, and advocacy groups. In this review, we will focus on discussing epidemiological factors that result in deviations and changes in treatment approaches for HCC.

The FDA granted orphan drug designation to darovasertib, a first-in-class oral, small molecular inhibitor of protein kinase C (PKC), for the treatment of uveal melanoma, on 2 May 2022. Primary uveal melanoma has a high risk of progressing to metastatic uveal melanoma, with a poor prognosis. The activation of the PKC and mitogen-activated protein kinase pathways play an essential role in the pathogenesis of uveal melanoma, and mutations in the G protein subunit alpha q (GNAQ), and G protein subunit alpha11 (GNA11) genes are considered early events in the development of uveal melanoma. Compared to other PKC inhibitors, such as sotrastaurin and enzastaurin, darovasertib is significantly more potent in inhibiting conventional (α, β) and novel (δ, ϵ, η, θ) PKC proteins and has a better tolerability and safety profile. Current Phase I/II clinical trials indicated that darovasertib, combined with the Mitogen-activated protein kinase/Extracellular (MEK) inhibitors, binimetinib or crizotinib, produced a synergistic effect of uveal melanoma. In this article, we summarize the development of drugs for treating uveal melanomas and discuss problems associated with current treatments. We also discuss the mechanism of action, pharmacokinetic profile, adverse effects, and clinical trial for darovasertib, and future research directions for treating uveal melanoma.

Introduction: The overexpression of ATP-binding cassette (ABC) transporters, ABCB1 and ABCG2, are two of the major mediators of multidrug resistance (MDR) in cancers. Although multiple ABCB1 and ABCG2 inhibitors have been developed and some have undergone evaluation in clinical trials, none have been clinically approved. The compound, MK-2206, an inhibitor of the protein kinases AKT1/2/3, is undergoing evaluation in multiple clinical trials for the treatment of certain types of cancers, including those resistant to erlotinib. In this in vitro study, we conducted in vitro experiments to determine if MK-2206 attenuates multidrug resistance in cancer cells overexpressing the ABCB1 or ABCG2 transporter.Methodology: The efficacy of MK-2206 (0.03–1 μM), in combination with the ABCB1 transporter sub-strates doxorubicin and paclitaxel, and ABCG2 transporter substrates mitoxantrone, SN-38 and topotecan, were determined in the cancer cell lines, KB-C2 and SW620/Ad300, which overexpress the ABCB1 transporter or H460/MX20 and S1-M1-80, which overexpress the ABCG2 transporter, respectively. The expression level and the localization of ABCG2 transporter on the cancer cells membranes were determined using western blot and immunofluorescence assays, respectively, following the incubation of cells with MK-2206. Finally, the interaction between MK-2206 and human ABCG2 transporter was predicted using computer-aided molecular modeling.Results: MK-2206 significantly increased the efficacy of anticancer compounds that were substrates for the ABCG2 but not the ABCB1 transporter. MK-2206 alone (0.03–1 μM) did not significantly alter the viability of H460/MX20 and S1-M1-80 cancer cells, which overexpress the ABCG2 transporter, compared to cells incubated with vehicle. However, MK-2206 (0.3 and 1 μM) significantly increased the anticancer efficacy of mitoxantrone, SN-38 and topotecan, in H460/MX20 and S1-M1-80 cancer cells, as indicated by a significant decrease in their IC50 values, compared to cells incubated with vehicle. MK-2206 significantly increased the basal activity of the ABCG2 ATPase (EC50 = 0.46 μM) but did not significantly alter its expression level and sub-localization in the membrane. The molecular modeling results suggested that MK-2206 binds to the active pocket of the ABCG2 transporter, by a hydrogen bond, hydrophobic interactions and π-π stacking.Conclusion: These in vitro data indicated that MK-2206 surmounts resistance to mitoxantrone, SN-38 and topotecan in cancer cells overexpressing the ABCG2 transporter. If these results can be translated to humans, it is possible that MK-2206 could be used to surmount MDR in cancer cells overexpressing the ABCG2 transporter.

Abstract Background High mobility group box 1 protein (HMGB1) is an alarmin following its release by immune cells upon cellular activation or stress. High levels of extracellular HMGB1 play a critical role in impairing the clearance of invading pulmonary pathogens and dying neutrophils in the injured lungs of cystic fibrosis (CF) and acute respiratory distress syndrome (ARDS). A heparin derivative, 2-O, 3-O desulfated heparin (ODSH), has been shown to inhibit HMGB1 release from a macrophage cell line and is efficacious in increasing bacterial clearance in a mouse model of pneumonia. Thus, we hypothesized that ODSH can attenuate the bacterial burden and inflammatory lung injury in CF and we conducted experiments to determine the underlying mechanisms. Methods We determined the effects of ODSH on lung injury produced by Pseudomonas aeruginosa (PA) infection in CF mice with the transmembrane conductance regulator gene knockout (CFTR −/− ). Mice were given ODSH or normal saline intraperitoneally, followed by the determination of the bacterial load and lung injury in the airways and lung tissues. ODSH binding to HMGB1 was determined using surface plasmon resonance and in silico docking analysis of the interaction of the pentasaccharide form of ODSH with HMGB1. Results CF mice given 25 mg/kg i.p. of ODSH had significantly lower PA-induced lung injury compared to mice given vehicle alone. The CF mice infected with PA had decreased levels of nitric oxide (NO), increased levels of airway HMGB1 and HMGB1-impaired macrophage phagocytic function. ODSH partially attenuated the PA-induced alteration in the levels of NO and airway HMGB1 in CF mice. In addition, ODSH reversed HMGB1-impaired macrophage phagocytic function. These effects of ODSH subsequently decreased the bacterial burden in the CF lungs. In a surface plasmon resonance assay, ODSH interacted with HMGB1 with high affinity (KD = 3.89 × 10–8 M) and induced conformational changes that may decrease HMGB1’s binding to its membrane receptors, thus attenuating HMGB1-induced macrophage dysfunction. Conclusions The results suggest that ODSH can significantly decrease bacterial infection-induced lung injury in CF mice by decreasing both HMGB1-mediated impairment of macrophage function and the interaction of HMGB1 with membrane receptors. Thus, ODSH could represent a novel approach for treating CF and ARDS patients that have HMGB1-mediated lung injury. Graphic abstract

Disulfiram (DSF) is a thiocarbamate based drug that has been approved for treating alcoholism for over 60 years. Preclinical studies have shown that DSF has anticancer efficacy, and its supplementation with copper (CuII) significantly potentiates the efficacy of DSF. However, the results of clinical trials have not yielded promising results. The elucidation of the anticancer mechanisms of DSF/Cu (II) will be beneficial in repurposing DSF as a new treatment for certain types of cancer. DSF’s anticancer mechanism is primarily due to its generating reactive oxygen species, inhibiting aldehyde dehydrogenase (ALDH) activity inhibition, and decreasing the levels of transcriptional proteins. DSF also shows inhibitory effects in cancer cell proliferation, the self-renewal of cancer stem cells (CSCs), angiogenesis, drug resistance, and suppresses cancer cell metastasis. This review also discusses current drug delivery strategies for DSF alone diethyldithocarbamate (DDC), Cu (II) and DSF/Cu (II), and the efficacious component Diethyldithiocarbamate–copper complex (CuET).

The coronavirus SARS-CoV-2 of 2019 (COVID-19) causes a pandemic that has been diagnosed in more than 70 million people worldwide. Mild-to-moderate COVID-19 symptoms include coughing, fever, myalgia, shortness of breath, and acute inflammatory lung injury (ALI). In contrast, acute respiratory distress syndrome (ARDS) and respiratory failure occur in patients diagnosed with severe COVID-19. ARDS is mediated, at least in part, by a dysregulated inflammatory response due to excessive levels of circulating cytokines, a condition known as the “cytokine-storm syndrome.” Currently, there are FDA-approved therapies that attenuate the dysregulated inflammation that occurs in COVID-19 patients, such as dexamethasone or other corticosteroids and IL-6 inhibitors, including sarilumab, tocilizumab, and siltuximab. However, the efficacy of these treatments have been shown to be inconsistent. Compounds that activate the vagus nerve-mediated cholinergic anti-inflammatory reflex, such as the α7 nicotinic acetylcholine receptor agonist, GTS-21, attenuate ARDS/inflammatory lung injury by decreasing the extracellular levels of high mobility group box-1 (HMGB1) in the airways and the circulation. It is possible that HMGB1 may be an important mediator of the “cytokine-storm syndrome.” Notably, high plasma levels of HMGB1 have been reported in patients diagnosed with severe COVID-19, and there is a significant negative correlation between HMGB1 plasma levels and clinical outcomes. Nicotine can activate the cholinergic anti-inflammatory reflex, which attenuates the up-regulation and the excessive release of pro-inflammatory cytokines/chemokines. Therefore, we hypothesize that low molecular weight compounds that activate the cholinergic anti-inflammatory reflex, such as nicotine or GTS-21, may represent a potential therapeutic approach to attenuate the dysregulated inflammatory responses in patients with severe COVID-19.

Palbociclib was approved by the United States Food and Drug Administration for use, in combination with letrozole, as a first-line treatment for estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) postmenopausal metastatic breast cancer. However, recent studies show that palbociclib may be an inhibitor of the ABCB1 transporter, although this remains to be elucidated. Therefore, we conducted experiments to determine the interaction of palbociclib with the ABCB1 transporter. Our in vitro results indicated that the efficacy of palbociclib was significantly decreased in the ABCB1-overexpressing cell lines. Furthermore, the resistance of ABCB1-overexpressing cells to palbociclib was reversed by 3 μM of the ABCB1 inhibitor, verapamil. Moreover, the incubation of ABCB1-overexpressing KB-C2 and SW620/Ad300 cells with up to 5 μM of palbociclib for 72 h, significantly upregulated the protein expression of ABCB1. The incubation with 3 µM of palbociclib for 2h significantly increased the intracellular accumulation of [3H]-paclitaxel, a substrate of ABCB1, in ABCB1 overexpressing KB-C2 cells but not in the corresponding non-resistant parental KB-3-1 cell line. However, the incubation of KB-C2 cells with 3 μM of palbociclib for 72 h decreased the intracellular accumulation of [3H]-paclitaxel due to an increase in the expression of the ABCB1 protein. Palbociclib produced a concentration-dependent increase in the basal ATPase activity of the ABCB1 transporter (EC50 = 4.73 μM). Molecular docking data indicated that palbociclib had a high binding affinity for the ABCB1 transporter at the substrate binding site, suggesting that palbociclib may compete with other ABCB1 substrates for the substrate binding site of the ABCB1. Overall, our results indicate that palbociclib is a substrate for the ABCB1 transporter and that its in vitro anticancer efficacy is significantly decreased in cancer cells overexpressing the ABCB1.

Abstract Background Mechanical ventilation, in combination with supraphysiological concentrations of oxygen (i.e., hyperoxia), is routinely used to treat patients with respiratory distress, such as COVID-19. However, prolonged exposure to hyperoxia compromises the clearance of invading pathogens by impairing macrophage phagocytosis. Previously, we have shown that the exposure of mice to hyperoxia induces the release of the nuclear protein high mobility group box-1 (HMGB1) into the pulmonary airways. Furthermore, extracellular HMGB1 impairs macrophage phagocytosis and increases the mortality of mice infected with Pseudomonas aeruginosa (PA). The aim of this study was to determine whether GTS-21 (3-(2,4-dimethoxybenzylidene) anabaseine), an α7 nicotinic acetylcholine receptor (α7nAChR) agonist, could (1) inhibit hyperoxia-induced HMGB1 release into the airways; (2) enhance macrophage phagocytosis and (3) increase bacterial clearance from the lungs in a mouse model of ventilator-associated pneumonia. Method GTS-21 (0.04, 0.4, and 4 mg/kg) or saline were administered by intraperitoneal injection to mice that were exposed to hyperoxia (≥ 99% O2) and subsequently challenged with PA. Results The systemic administration of 4 mg/kg i.p. of GTS-21 significantly increased bacterial clearance, decreased acute lung injury and decreased accumulation of airway HMGB1 compared to the saline control. To determine the mechanism of action of GTS-21, RAW 264.7 cells, a macrophage-like cell line, were incubated with different concentrations of GTS-21 in the presence of 95% O2. The phagocytic activity of macrophages was significantly increased by GTS-21 in a dose-dependent manner. In addition, GTS-21 significantly inhibited the cytoplasmic translocation and release of HMGB1 from RAW 264.7 cells and attenuated hyperoxia-induced NF-κB activation in macrophages and mouse lungs exposed to hyperoxia and infected with PA. Conclusions Our results indicate that GTS-21 is efficacious in improving bacterial clearance and reducing acute lung injury via enhancing macrophage function by inhibiting the release of nuclear HMGB1. Therefore, the α7nAChR represents a possible pharmacological target to improve the clinical outcome of patients on ventilators by augmenting host defense against bacterial infections.

Abstract Background Cisplatin is a first-line drug for the treatment of human non-small cell lung cancer (NSCLC); however, the majority of patients will develop drug resistance after treatment. In order to overcome cisplatin resistance, it is important to understand the mechanisms underlying the resistance. Methods A gene microarray was used to screen for genes related to cisplatin resistance in NSCLC cell lines. Subsequently, the correlation between the HDAC, RXR and HtrA1 genes, in NSCLC, were verified using gene manipulation. Immunohistochemical staining was used to detect HDAC, RXR and HtrA1 expression in NSCLC specimens. Proliferation, migration and invasion assays were performed in vitro and in vivo to determine the role of the HDAC/RXR/HtrA1 signaling axis in cisplatin resistance, and luciferase reporter analysis and ChIP assays were performed to ascertain the mechanisms by which HDAC and RXR regulate the expression of HtrA1. Furthermore, in vitro and in vivo experiments were conducted in NSCLC cisplatin-resistant NSCLC to elucidate the effect of the low molecular weight compound, DW22, which targets the NSCLC cisplatin resistance HDAC/RXR/HtrA1 signaling pathway. Results HtrA1 was identified as a cisplatin resistance-related gene in NSCLC cells. The regulation of HtrA1 by HDAC and RXR significantly decreased the efficacy of cisplatin in NSCLC cells resistant to cisplatin. Immunohistochemistry results showed a negative relationship between HDAC1 and HtrA1, and a positive relationship between RXRα and HtrA1 in NSCLC patients’ tissues. Notably, the expression of HDAC1 and HtrA1 can be considered as biomarkers for the efficacy of platinum-based drugs and prognosis in NSCLC patients. Mechanistically, the heterodimers of the nuclear receptor RXR, in combination with the enzyme, HDAC, regulate the transcription of HtrA1 in NSCLC cells. The rescue of HtrA1 expression by dual targeting of HDAC and RXR with the compound, DW22, significantly inhibited the proliferation, migration and invasion of NSCLC cells resistant to cisplatin, and induced NSCLC cell apoptosis. Conclusion Our results indicate that HtrA1, a cisplatin resistance-related gene, is synergistically regulated by HDAC and RXR in NSCLC. Targeting the HDAC/RXR/HtrA1 signaling axis can rescue HtrA1 expression and reverse cisplatin resistance in NSCLC.

Abstract Background Oxygen therapy, using supraphysiological concentrations of oxygen (hyperoxia), is routinely administered to patients who require respiratory support including mechanical ventilation (MV). However, prolonged exposure to hyperoxia results in acute lung injury (ALI) and accumulation of high mobility group box 1 (HMGB1) in the airways. We previously showed that airway HMGB1 mediates hyperoxia-induced lung injury in a mouse model of ALI. Cholinergic signaling through the α7 nicotinic acetylcholine receptor (α7nAChR) attenuates several inflammatory conditions. The aim of this study was to determine whether 3–(2,4 dimethoxy-benzylidene)-anabaseine dihydrochloride, GTS-21, an α7nAChR partial agonist, inhibits hyperoxia-induced HMGB1 accumulation in the airways and circulation, and consequently attenuates inflammatory lung injury. Methods Mice were exposed to hyperoxia (≥99% O2) for 3 days and treated concurrently with GTS-21 (0.04, 0.4 and 4 mg/kg, i.p.) or the control vehicle, saline. Results The systemic administration of GTS-21 (4 mg/kg) significantly decreased levels of HMGB1 in the airways and the serum. Moreover, GTS-21 (4 mg/kg) significantly reduced hyperoxia-induced acute inflammatory lung injury, as indicated by the decreased total protein content in the airways, reduced infiltration of inflammatory monocytes/macrophages and neutrophils into the lung tissue and airways, and improved lung injury histopathology. Conclusions Our results indicate that GTS-21 can attenuate hyperoxia-induced ALI by inhibiting extracellular HMGB1-mediated inflammatory responses. This suggests that the α7nAChR represents a potential pharmacological target for the treatment regimen of oxidative inflammatory lung injury in patients receiving oxygen therapy.

Abstract Chemoresistance, whether intrinsic or acquired, is a major obstacle in the treatment of cancer. The resistance of cancer cells to chemotherapeutic drugs can result from various mechanisms. Over the last decade, it has been reported that 1ong noncoding RNAs (lncRNAs) can mediate carcinogenesis and drug resistance/sensitivity in cancer cells. This article reviews, in detail, recent studies regarding the roles of lncRNAs in mediating drug resistance.

Isochrysis is commercially available marine algae used for animal feed, human nutrient supplements, and biodiesel. The Isochrysis species is one of five genera of haptophytes that produces unique, long-chain lipids known as alkenones that are promising new ingredients for green cosmetics, personal care products and pharmaceutical delivery. However, there is a lack of toxicity data for alkenones in animals, thus limiting their use in humans. In this study, we performed acute oral, acute dermal, and repeated 28-day dermal toxicity studies, using female SAS Sprague Dawley Rats. Our behavioral studies indicated that the specific alkenones had no overt behavioural effects at oral doses up to 4000 mg/kg. In the acute and chronic dermal toxicity studies, the alkenones produced less irritation and did not significantly damage the skin based on the Draize skin reaction scale and trans-epidermal water loss readings compared to the positive control, 1% sodium lauryl sulfate. Overall, our results indicated that alkenones are safe in Sprague Dawley rats, suggesting that they could be used for both oral and dermal formulations, although additional studies will be required.

Microwave-assisted synthetic methods have emerged as a popular technique for surface modification and the functionalization of multi-walled carbon nanotubes (MWCNTs) for diverse drug delivery applications. Microwave-induced functionalization of MWCNTs provides a high functionalization and requires less time than conventional techniques. Microwave methods are simple, fast, and effective for the covalent and noncovalent conjugation of MWCNTs with various biomolecules and polymers. The present review focuses on the synthetic and drug delivery applications of microwave irradiation techniques (MITs) for the functionalization of MWCNTs, using amino acids and other molecular frameworks containing amino groups, vitamins, proteins, epoxy moieties, metal nanoparticles, and polymers.

In men, prostate cancer (PC) is the most frequently diagnosed cancer, causing an estimated 375,000 deaths globally. Currently, existing therapies for the treatment of PC, notably metastatic cases, have limited efficacy due to drug resistance and problematic adverse effects. Therefore, it is imperative to discover and develop novel drugs for treating PC that are efficacious and do not produce intolerable adverse or toxic effects. Condensed quinolines are naturally occurring anticancer compounds. In this study, we determined the in vitro efficacy of IND-2 (4-chloro-2-methylpyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinolone) in the PC lines, PC-3 and DU-145. IND-2 significantly inhibited the proliferation of PC-3 and DU-145, with IC50 values of 3 µM and 3.5 µM, respectively. The incubation of PC-3 cells with 5 and 10 µM of IND-2 caused the loss of the mitochondrial membrane potential in PC-3 cells. Furthermore, IND-2, at 5 µM, increased the expression of cleaved caspase-3, cleaved caspase-7 and cleaved poly (ADP-ribose) polymerase (PARP). The incubation of PC-3 cells with 5 µM of IND-2 significantly decreased the expression of the apoptotic protein, B-cell lymphoma 2 (Bcl-2). Furthermore, 5 and 10 µM of IND-2 produced morphological changes in PC-3 cells characteristic of apoptosis. Interestingly, IND-2 (2.5, 5 and 10 µM) also induced mitotic catastrophe in PC-3 cells, characterized by the accumulation of multinuclei. The incubation of DU-145 cells with 1.25 and 5 μM of IND-2 significantly increased the levels of reactive oxygen species (ROS). Finally, IND-2, at 10 μM, inhibited the catalytic activity of topoisomerase IIα. Overall, our findings suggest that IND-2 could be a potential lead compound for the development of more efficacious compounds for the treatment of PC.

Multiwalled carbon nanotubes (MWCNTs) are elongated, hollow cylindrical nanotubes made of sp2 carbon. MWCNTs have attracted significant attention in the area of drug delivery due to their high drug-loading capacity and large surface area. Furthermore, they can be linked to bioactive ligands molecules via covalent and noncovalent bonds that allow for the targeted delivery of anticancer drugs such as doxorubicin. The majority of methodologies reported for the functionalization of MWCNTs for drug delivery are quite complex and use expensive linkers and ligands. In the present study, we report a simple, cost-effective approach for functionalizing MWCNTs with the carbohydrate ligands, galactose (GA), mannose (MA) and lactose (LA), using lysine as a linker. The doxorubicin (Dox)-loaded functionalized MWCNTs were characterized using FT-IR, NMR, Raman, XRD and FE-SEM. The drug–loaded MWCNTs were evaluated for drug loading, drug release and cell toxicity in vitro, in breast cancer cells. The results indicated that the carbohydrate-modified lysinated MWCNTs had greater Dox loading capacity, compared to carboxylated MWCNTs (COOHMWCNTs) and lysinated MWCNTs (LyMWCNTs). In vitro drug release experiments indicated that the carbohydrate functionalized LyMWCNTs had higher Dox release at pH 5.0, compared to the physiological pH of 7.4, over 120 h, indicating that they are suitable candidates for targeting the tumor microenvironment as a result of their sustained release profile of Dox. Doxorubicin-loaded galactosylated MWCNTs (Dox-GAMWCNTs) and doxorubicin loaded mannosylated MWCNTs (Dox-MAMWCNTs) had greater anticancer efficacy and cellular uptake, compared to doxorubicin–loaded lactosylated MWCNTs (Dox-LAMWCNTs) and pure Dox, in MDA-MB231 and MCF7 breast cancer cells. However, neither the ligand conjugated multiwall blank carbon nanotubes (GAMWCNTs, MAMWCNTs and LAMWCNTs) nor the lysinated multiwalled blank carbon nanotubes produced significant toxicity in the normal cells. Our results suggest that sugar-tethered multiwalled carbon nanotubes, especially the galactosylated (Dox-GAMWCNTs) and mannosylated (Dox-MAMWCNTs) formulations, may be used to improve the targeted delivery of anticancer drugs to breast cancer cells.

Chronic myelogenous leukemia (CML) typically results from a reciprocal translocation between chromosomes 9 and 22 to produce the bcr-abl oncogene that when translated, yields the p210 BCR-ABL protein in more than 90% of all CML patients. This protein has constitutive tyrosine kinase activity that activates numerous downstream pathways that ultimately produces uncontrolled myeloid proliferation. Although the use of the BCR-ABL tyrosine kinase inhibitors (TKIs), such as imatinib, nilotinib, dasatinib, bosutinib, and ponatinib have increased the overall survival of CML patients, their use is limited by drug resistance and severe adverse effects. Therefore, there is the need to develop novel compounds that can overcome these problems that limit the use of these drugs. Therefore, in this study, we sought to find novel compounds using Hypogen and Hiphip pharmacophore models based on the structures of clinically approved BCR-ABL TKIs. We also used optimal pharmacophore models such as three-dimensional queries to screen the ZINC database to search for potential BCR-ABL inhibitors. The hit compounds were further screened using Lipinski’s rule of five, ADMET and molecular docking, and the efficacy of the hit compounds was evaluated. Our in vitro results indicated that compound ZINC21710815 significantly inhibited the proliferation of K562, BaF3/WT, and BaF3/T315I leukemia cells by inducing cell cycle arrest. The compound ZINC21710815 decreased the expression of p-BCR-ABL, STAT5, and Crkl and produced apoptosis and autophagy. Our results suggest that ZINC21710815 may be a potential BCR-ABL inhibitor that should undergo in vivo evaluation.

The efficacy of anti-cancer drugs in patients can be attenuated by the development of multi-drug resistance (MDR) due to ATP-binding cassette (ABC) transporters overexpression. In this in vitro study, we determined the reversal efficacy of the epidermal growth factor receptor (EFGR) inhibitor, saptinib, in SW620 and SW720/Ad300 colon cancer cells and HEK293/ABCB1 cells which overexpress the ABCB1 transporter. Sapitinib significantly increased the efficacy of paclitaxel and doxorubicin in ABCB1 overexpressing cells without altering the expression or the subcellular location of the ABCB1 transporter. Sapitinib significantly increased the accumulation of [3H]-paclitaxel in SW620/AD300 cells probably by stimulating ATPase activity which could competitively inhibit the uptake of [3H]-paclitaxel. Furthermore, sapitinib inhibited the growth of resistant multicellular tumor spheroids (MCTS). The docking study indicated that sapitinib interacted with the efflux site of ABCB1 transporter by π-π interaction and two hydrogen bonds. In conclusion, our study suggests that sapitinib surmounts MDR mediated by ABCB1 transporter in cancer cells.

In this study, we investigated the efficacy of methyl-cantharidimide (MCA), a cantharidin (CTD) analog, as an anticancer drug, in cancer cells overexpressing either ABCB1 or ABCG2 transporters and in cisplatin-resistant cancer cells. The results indicated that: (i) MCA was efficacious in the ABCB1-overexpressing cell line, KB-C2, and the ABCB1-gene-transfected cell line, HEK293/ABCB1 (IC50 from 6.37 to 8.44 mM); (ii) MCA was also efficacious in the ABCG2-overexpressing cell line, NCI-H460/MX20, and the ABCG2-gene-transfected cell lines, HEK293/ABCG2-482-R2, HEK293/ABCG2-482-G2, and the HEK293/ABCG2-482-T7 cell lines (IC50 from 6.37 to 9.70 mM); (iii) MCA was efficacious in the cisplatin resistant cancer cell lines, KCP-4 and BEL-7404/CP20 (IC50 values from 7.05 to 8.16 mM); (iv) MCA (up to 16 mM) induced apoptosis in both BEL-7404 and BEL-7404/CP20 cancer cells; (v) MCA arrested both BEL-7404 and BEL-7404/CP20 cancer cells in the G0/G1 phase of the cell cycle; (vi) MCA (8 mM) upregulated the expression level of the protein, unc-5 netrin receptor B (UNC5B) in HepG2 and BEL-7404 cancer cells. Overall, our results indicated that MCA's efficacy in ABCB1- and ABCG2-overexpressing and cisplatin resistant cancer cells is due to the induction of apoptosis and cell cycle arrest in the G0/G1 phase.

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1186/s10020-020-00265-0

A novel series of 4-anilinoquinazoline analogues, DW (1–10), were evaluated for anticancer efficacy in human breast cancer (BT-20) and human colorectal cancer (CRC) cell lines (HCT116, HT29, and SW620). The compound, DW-8, had the highest anticancer efficacy and selectivity in the colorectal cancer cell lines, HCT116, HT29, and SW620, with IC50 values of 8.50 ± 2.53 µM, 5.80 ± 0.92 µM, and 6.15 ± 0.37 µM, respectively, compared to the non-cancerous colon cell line, CRL1459, with an IC50 of 14.05 ± 0.37 µM. The selectivity index of DW-8 was >2-fold in colon cancer cells incubated with vehicle. We further determined the mechanisms of cell death induced by DW-8 in SW620 CRC cancer cells. DW-8 (10 and 30 µM) induced apoptosis by (1) producing cell cycle arrest at the G2 phase; (2) activating the intrinsic apoptotic pathway, as indicated by the activation of caspase-9 and the executioner caspases-3 and 7; (3) nuclear fragmentation and (4) increasing the levels of reactive oxygen species (ROS). Overall, our results suggest that DW-8 may represent a suitable lead for developing novel compounds to treat CRC.

Abstract Flavonoids are polyphenols that are found in numerous edible plant species. Data obtained from preclinical and clinical studies suggest that specific flavonoids are chemo-preventive and cytotoxic against various cancers via a multitude of mechanisms. However, the clinical use of flavonoids is limited due to challenges associated with their effective use, including (1) the isolation and purification of flavonoids from their natural resources; (2) demonstration of the effects of flavonoids in reducing the risk of certain cancer, in tandem with the cost and time needed for epidemiological studies, and (3) numerous pharmacokinetic challenges (e.g., bioavailability, drug–drug interactions, and metabolic instability). Currently, numerous approaches are being used to surmount some of these challenges, thereby increasing the likelihood of flavonoids being used as chemo-preventive drugs in the clinic. In this review, we summarize the most important challenges and efforts that are being made to surmount these challenges.

A novel series of 3-((2-chloroquinolin-3-yl)methylene)indolin-2-ones were synthesized, using the ‘molecular hybridization approach’ and evaluated for anticancer efficacy. Eleven 3-((2-chloroquinolin-3-yl)methylene)indolin-2-ones (LM01 to LM11) were synthesized and evaluated for in vitro cytotoxic efficacy in cancer (ovarian, prostate and colon) and two non-cancerous cell lines. Among the 3-((2-chloroquinolin-3-yl)methylene)indolin-2-one derivatives, LM08, with a 6-Cl substitution in the 3-quinolinyl moiety, had selective and potent cytotoxic efficacy in the ovarian cancer cell line A2780. Further mechanistic investigations indicated that LM08 significantly inhibited the clonogenic survival of A2780 cancer cells, which was mediated by inducing apoptosis.

Supplemental oxygen therapy with supraphysiological concentrations of oxygen (hyperoxia; >21% O2) is a life-saving intervention for patients experiencing respiratory distress. However, prolonged exposure to hyperoxia can compromise bacterial clearance processes, due to oxidative stress-mediated impairment of macrophages, contributing to the increased susceptibility to pulmonary infections. This study reports that the activation of the α7 nicotinic acetylcholine receptor (α7nAChR) with the delete allosteric agonistic-positive allosteric modulator, GAT107, decreases the bacterial burden in mouse lungs by improving hyperoxia-induced lung redox imbalance. The incubation of RAW 264.7 cells with GAT107 (3.3 µM) rescues hyperoxia-compromised phagocytic functions in cultured macrophages, RAW 264.7 cells, and primary bone marrow-derived macrophages. Similarly, GAT107 (3.3 µM) also attenuated oxidative stress in hyperoxia-exposed macrophages, which prevents oxidation and hyper-polymerization of phagosome filamentous actin (F-actin) from oxidation. Furthermore, GAT107 (3.3 µM) increases the (1) activity of superoxide dismutase 1; (2) activation of Nrf2 and (3) the expression of heme oxygenase-1 (HO-1) in macrophages exposed to hyperoxia. Overall, these data suggest that the novel α7nAChR compound, GAT107, could be used to improve host defense functions in patients, such as those with COVID-19, who are exposed to prolonged periods of hyperoxia.

Abstract Previously, we have shown that N,N-dimethylacetamide (DMA) prevents inflammation-induced preterm birth in a murine model, inhibits lipopolysaccharide (LPS)-induced increases in placental proinflammatory cytokines and upregulates the antiinflammatory cytokine interleukin-10 (IL-10). However, DMA’s mechanism of action remains to be elucidated. In the current study, we investigate how DMA produces its antiinflammatory effect. Using in vitro and ex vivo models, we show that DMA suppresses secretion of proinflammatory cytokines in lipopolysaccharide (LPS)-induced RAW 264.7 cells, TNFα-challenged JEG-3 cells and LPS-stimulated human placental explants. DMA significantly attenuated secretion of TNFα, IL-6, IL-10 and granulocyte macrophage colony stimulating factor (GM-CSF) from LPS-stimulated RAW 264.7 cells; IL-6 secretion from TNFα-stimulated JEG-3 cells; and TNFα, IL-6, IL-10, GM-CSF and Interleukin-8 (IL-8) from LPS-stimulated human placental explants. We further investigated whether DMA’s effect on cytokine expression involves the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. DMA (10 mM) significantly inhibited degradation of nuclear factor of kappa light polypeptide gene enhancer in B cell inhibitor a (IκBα) in LPS-stimulated RAW 264.7 cells, but there was no significant change in the expression of phosphorylated or native forms of downstream proteins in the MAPK pathway. In addition, DMA significantly attenuated luciferase activity in cells co-transfected with NF-κB-Luc reporter plasmid, but not with AP-1-Luc or CEBP-Luc reporters. Overall, our findings suggest that the antiinflammatory activity of DMA is mediated by inhibition of the NF-κB pathway via decreased IκBa degradation.

New chrysin-De-allyl-Pac-1 hybrid analogues, tethered with variable heterocyclic systems (4a–4o), were rationally designed and synthesized. The target compounds were screened for in vitro antiproliferative efficacy in the triple-negative breast cancer (TNBC) cell line, MDA-MB-231, and normal human mammary epithelial cells (HMECs). Two compounds, 4g and 4i, had the highest efficacy and selectivity towards MDA-MB-231 cells, and thus, were further evaluated by mechanistic experiments. The results indicated that both compounds 4g and 4i induced apoptosis by (1) inducing cell cycle arrest at the G2 phase in MDA-MB-231 cells, and (2) activating the intrinsic apoptotic pathways in a concentration-dependent manner. Physicochemical characterizations of these compounds suggested that they can be further optimized as potential anticancer compounds for TNBC cells. Overall, our results suggest that 4g and 4i could be suitable leads for developing novel compounds to treat TNBC.

The Editors-in-Chief would like to alert readers that this article (Sitapara et al. 2014) is part of an investigation being conducted by the journal following the conclusions of an institutional enquiry at the University of Liverpool with respect to the quantitative mass spectrometry-generated results regarding acetylated and redox-modified HMGB1.

The inhibition of apoptosis, disruption of cellular microtubule dynamics, and over-activation of the epithelial mesenchymal transition (EMT), are involved in the progression, metastasis, and resistance of colorectal cancer (CRC) to chemotherapy. Therefore, the design of a molecule that can target these pathways could be an effective strategy to reverse CRC progression and metastasis. In this study, twelve novel silybin derivatives, HM015a-HM015k (15a−15k) and compound 17, were screened for cytotoxicity in CRC cell lines. Compounds HM015j and HM015k (15k and 15j) significantly decreased cell proliferation, inhibited colony formation, and produced cell cycle arrest in CRC cells. Furthermore, 15k significantly induced the formation of reactive oxygen species and apoptosis. It induced the cleavage of the intrinsic apoptotic protein (Bax p21) to its more efficacious fragment, p18. Compound 15k also inhibited tubulin expression and disrupted its structure. Compound 15k significantly decreased metastatic LOVO cell migration and invasion. Furthermore, 15k reversed mesenchymal morphology in HCT116 and LOVO cells. Additionally, 15k significantly inhibited the expression of the mesenchymal marker N-cadherin and upregulated the expression of the epithelial marker, E-cadherin. Compound 15k inhibited the expression of key proteins known to induce EMT (i.e., DVL3, β-catenin, c-Myc) and upregulated the anti-metastatic protein, cyclin B1. Overall, in vitro, 15k significantly inhibited CRC progression and metastasis by inhibiting apoptosis, tubulin activity and the EMT pathways. Overall, these data suggest that compound 15k should be tested in vivo in a CRC animal model for further development.

This study was designed to determine the in vitro mechanisms by which the novel silybin derivative, (E)-3-(3-(benzyloxy) phenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (HM015k or 15k), produces its anticancer efficacy in ovarian cancer cells. Compound 15k induced apoptosis in ovarian cancer cells in a time-dependent manner by significantly upregulating the expression of Bax and Bak and downregulating the expression of Bcl-2. Interestingly, 15k induced the cleavage of Bax p21 into its more efficacious cleaved form, Bax p18. In addition, caspase 3 and caspase 9 were cleaved to their active forms, inducing the cleavage of poly ADP ribose polymerase (PARP) and β-catenin. Furthermore, in OV2008 cells, 15k induced significant cleavage in nuclear β-catenin to primarily inactive fragments of lower molecular weight. Furthermore, 15k reversed the metastatic potential of OV2008 cells by inhibiting their migration and invasiveness. The mesenchymal phenotype in OV2008 was reversed by 15k, causing cells to be rounder with epithelial—like phenotypes. The 15k-induced reversal was further confirmed by significant upregulation of the E-cadherin expression, an epithelial marker, while N-cadherin, a mesenchymal marker, was downregulated in OV2008 cells. Compound 15k inhibited the expression of the oncogenic c-Myc protein, downregulated proteins DVL3 and DVL2 and significantly upregulated cyclin B1. Also, 15k significantly downregulated the expression levels of ABCG2 and ABCB1 transporters in resistant ABCG2 overexpressing H460/MX20 and resistant ABCB1 overexpressing MDCK/MDR1 cells, respectively. Finally, 15k was safe in zebrafish in vivo model at concentrations up to 10 μM and induced no major toxicities in cardiac, morphology and swimming position parameters. Overall, 15k is a multi-targeted inhibitor with efficacy against metastatic and resistant ovarian cancer. Future in vivo studies will be conducted to determine the efficacy of 15k in tumor-bearing animals.

Prolonged exposure to hyperoxia results in acute lung injury (ALI), accompanied by a significant elevation in the levels of proinflammatory cytokines and leukocyte infiltration in the lungs. However, the mechanisms underlying hyperoxia-induced proinflammatory ALI remain to be elucidated. In this study, we investigated the role of the proinflammatory cytokine high mobility group box protein 1 (HMGB1) in hyperoxic inflammatory lung injury, using an adult mouse model. The exposure of C57BL/6 mice to ≥99% O2 (hyperoxia) significantly increased the accumulation of HMGB1 in the bronchoalveolar lavage fluids (BALF) prior to the onset of severe inflammatory lung injury. In the airways of hyperoxic mice, HMGB1 was hyperacetylated and existed in various redox forms. Intratracheal administration of recombinant HMGB1 (rHMGB1) caused a significant increase in leukocyte infiltration into the lungs compared to animal treated with a non-specific peptide. Neutralizing anti-HMGB1 antibodies, administrated before hyperoxia significantly attenuated pulmonary edema and inflammatory responses, as indicated by decreased total protein content, wet/dry weight ratio, and numbers of leukocytes in the airways. This protection was also observed when HMGB1 inhibitors were administered after the onset of the hyperoxic exposure. The aliphatic antioxidant, ethyl pyruvate (EP), inhibited HMGB1 secretion from hyperoxic macrophages and attenuated hyperoxic lung injury. Overall, our data suggest that HMGB1 plays a critical role in mediating hyperoxic ALI through the recruitment of leukocytes into the lungs. If these results can be translated to humans, they suggest that HMGB1 inhibitors provide treatment regimens for oxidative inflammatory lung injury in patients receiving hyperoxia through mechanical ventilation.

Preterm birth is defined as any delivery before 37 complete weeks of gestation. It is a universal challenge in the field of obstetrics owing to its high rate of mortality, long-term morbidity, associated human suffering and economic burden. In the United States, about 12.18% deliveries in 2009 were preterm, producing an exorbitant cost of $5.8 billion. Infection-associated premature rupture of membranes (PROM) accounts for 40% of extremely preterm births (