Discovery of Sophoridine α-Aryl Propionamide Derivative ZM600 as a Novel Antihepatic Fibrosis Agent.

Hepatic stellate cells (HSCs) activation is a key event in the development of liver fibrosis, and blockage of the activation of HSCs has been shown to alleviate liver fibrosis. Sophoridine, a bioactive alkaloid found in many Chinese herbs, exhibits a broad spectrum of pharmacological effects, but its activities are not strong. In this study, a series of structurally modified derivatives of sophoridine were designed and synthesized. Among them, sophoridine α-aryl propionamide derivative ZM600 displayed a significant inhibitory effect on the activation of HSCs. The in vivo experiment demonstrated that ZM600 markedly ameliorated carbon tetrachloride (CCl4) and bile duct ligation (BDL)-induced liver fibrosis with a significant improvement of extracellular matrix deposition. Mechanism investigations revealed that ZM600 specifically inhibited the activation of NF-κB, PI-3K/AKT, and TGF-ß/Smads signaling pathways. These results suggest that ZM600 has a protective effect on liver fibrosis, which provides a new candidate for the treatment of liver fibrosis.

Structure-Activity Relationship Study of (E)-3-(6-Fluoro-1H-indol-3-Yl)-2-methyl-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (FC116) Against Metastatic Colorectal Cancers Resistant to Oxaliplatin.

Advanced metastatic colorectal cancer (mCRC) and the development of drug resistance to chemotherapy pose significant challenges in clinical settings. In previous studies, we have demonstrated the potent cytotoxic activity of (E)-3-(6-fluoro-1H-indol-3-yl)-2-methyl-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (FC116) and related 30 derivatives against mCRC by targeting microtubules. In this study, we aimed to evaluate the efficacy of the 31 compounds and explore the structure-activity relationship (SAR) against oxaliplatin-resistant mCRC. We found that most of the derivatives showed high sensitivity toward the oxaliplatin-resistant HCT-116/L cells. Particularly, FC116 exhibited a better GI50 value against the resistant mCRC cell line, HCT-116/L, compared to standard therapies. We also observed a safer therapeutic window for FC116 and a synergistic effect when it was used in combination with oxaliplatin. Mechanistically, FC116 induced the G2/M phase arrest by downregulating cyclin B1 expression through its interaction with microtubules in resistant colorectal cancer cells. Furthermore, in vivo experiments demonstrated that FC116 significantly suppressed tumor growth, achieving a 78% reduction at a dose of 3 mg/kg, which was superior to the 40% reduction achieved by oxaliplatin treatment. Overall, our findings suggest that the indole-chalcone compound FC116 represents a promising lead for chemotherapy in oxaliplatin-resistant mCRC.

Diallyl trisulfide inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung cancer via modulating gut microbiota and the PPARγ/NF-κB pathway.

Smoking is the primary risk factor for developing lung cancer. Chemoprevention could be a promising strategy to reduce the incidence and mortality rates of lung cancer. Recently, we reported that A/J mice exposed to tobacco smoke carcinogens displayed the reshaping of gut microbiota. Additionally, garlic oil was found to effectively inhibit the carcinogenic effects of tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in lung tumorigenesis. Diallyl trisulfide (DATS), which is the predominant compound in garlic oil, exhibits various biological activities. To further explore the chemopreventive action and potential mechanism of DATS on lung tumorigenesis, we established a lung adenocarcinoma model in A/J mice stimulated by NNK. Subsequently, we employed multi-omics combined molecular biology technologies to clarify the mechanism. The results indicated that DATS significantly decreased the number of lung tumors in NNK induced A/J mice. Interestingly, we discovered that DATS could modulate gut microbiota, particularly increasing the abundance of F. rodentium, which has inhibitory effects on tumor growth. Mechanistically, DATS could activate the PPARγ pathway, leading to the negative regulation of the NF-κB signaling pathway and subsequent suppression of NF-κB-mediated inflammatory factors. Collectively, these findings provide support for DATS as a potential novel chemopreventive agent for tobacco carcinogen-induced lung cancer.

Diallyl Disulfide Blocks Cigarette Carcinogen 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone-Induced Lung Tumorigenesis via Activation of the Nrf2 Antioxidant System and Suppression of NF-κB Inflammatory Response.

Chemoprevention is a potential strategy to reduce lung cancer incidence and death. Recently, we reported that garlic oil significantly inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis. Diallyl disulfide (DADS) is a bioactive ingredient in garlic. Our goal was to examine the chemopreventive effectiveness and mechanism of DADS on NNK-triggered lung cancer in vivo and in vitro in the current investigation. The results indicated that DADS significantly reduced the number of lung nodules in the NNK-induced A/J mice. Consistent with the in vivo results, DADS markedly inhibited NNK-induced decrease of MRC-5 cells' viability. Mechanistically, DADS could promote Nrf2 dissociated from the Keap1-Nrf2 complex and accelerate Nrf2 nuclear translocation, which in turn upregulates its downstream target genes. Besides, DADS further inhibited the NF-κB signaling cascade, thus reducing the accumulation of inflammatory factors. Collectively, these discoveries supported the potential of DADS as a novel candidate for the chemoprevention of tobacco-carcinogen-induced lung cancer.

Structure-Based Design of Novel Alkynyl Thio-Benzoxazepinone Receptor-Interacting Protein Kinase-1 Inhibitors: Extending the Chemical Space from the Allosteric to ATP Binding Pockets.

Systemic inflammatory response syndrome (SIRS), characterized by severe systemic inflammation, represents a major cause of health loss, potentially leading to multiple organ failure, shock, and death. Exploring potent RIPK1 inhibitors is an effective therapeutic strategy for SIRS. Recently, we described thio-benzoxazepinones as novel RIPK1 inhibitors and confirmed their anti-inflammatory activity. Herein, we further synthesized novel thio-benzoxazepinones by introducing substitutions on the benzene ring by an alkynyl bridge in order to extend the chemical space from the RIPK1 allosteric to ATP binding pockets. The in vitro cell and kinase assays found that compounds 2 and 29 showed highly potent activity against necroptosis (EC50 = 3.7 and 3.2 nM) and high RIPK1 inhibitory activity (Kd = 9.7 and 70 nM). Prominently, these two analogues possessed better in vivo anti-inflammatory effects than the clinical candidate GSK'772 and effectively blocked hypothermia and deaths in a TNFα-induced SIRS model.

Roxarsone inhibits hepatic stellate cell activation and ameliorates liver fibrosis by blocking TGF-ß1/Smad signaling pathway.

Hepatic fibrosis is a pathological change caused by chronic liver injury and self-repair, and it is the inevitable stage of the development of chronic liver disease to cirrhosis or even liver cancer. Activation of hepatic stellate cells (HSCs) is a core event in the development of liver fibrosis and blockage of the activation of HSCs has been shown to alleviate liver fibrosis. Roxarsone, an organoarsenic additive, with antibiotic effect, growth promotion and improving feed efficiency, is widely used in livestock and animal production. The purpose of this study was to evaluate the therapeutic effect of Roxarsone on liver fibrosis and explore the possible mechanism. We found that Roxarsone could inhibit transforming growth factor-ß1 (TGF-ß1) induced the activation of HSCs and weaken the migration ability. Moreover, Roxarsone administration significantly ameliorated CCl4-induced liver fibrosis in mice with improvement of liver function and decreases of deposition of extracellular matrix (ECM). Mechanism investigations revealed that Roxarsone specifically inhibited the activation of TGF-ß1/Smad signaling pathway, but had no effect on MAPK and PI3K/AKT pathways. These results suggest that Roxarsone has a protective effect on liver fibrosis which provides a new candidate for the treatment of liver fibrosis.

Malignant progression of liver cancer progenitors requires lysine acetyltransferase 7-acetylated and cytoplasm-translocated G protein GαS.

BACKGROUND AND AIMS: Hepatocarcinogenesis goes through HCC progenitor cells (HcPCs) to fully established HCC, and the mechanisms driving the development of HcPCs are still largely unknown. APPROACH AND RESULTS: Proteomic analysis in nonaggregated hepatocytes and aggregates containing HcPCs from a diethylnitrosamine-induced HCC mouse model was screened using a quantitative mass spectrometry-based approach to elucidate the dysregulated proteins in HcPCs. The heterotrimeric G stimulating protein α subunit (GαS) protein level was significantly increased in liver cancer progenitor HcPCs, which promotes their response to oncogenic and proinflammatory cytokine IL-6 and drives premalignant HcPCs to fully established HCC. Mechanistically, GαS was located at the membrane inside of hepatocytes and acetylated at K28 by acetyltransferase lysine acetyltransferase 7 (KAT7) under IL-6 in HcPCs, causing the acyl protein thioesterase 1-mediated depalmitoylation of GαS and its cytoplasmic translocation, which were determined by GαS K28A mimicking deacetylation or K28Q mimicking acetylation mutant mice and hepatic Kat7 knockout mouse. Then, cytoplasmic acetylated GαS associated with signal transducer and activator of transcription 3 (STAT3) to impede its interaction with suppressor of cytokine signaling 3, thus promoting in a feedforward manner STAT3 phosphorylation and the response to IL-6 in HcPCs. Clinically, GαS, especially K28-acetylated GαS, was determined to be increased in human hepatic premalignant dysplastic nodules and positively correlated with the enhanced STAT3 phosphorylation, which were in accordance with the data obtained in mouse models. CONCLUSIONS: Malignant progression of HcPCs requires increased K28-acetylated and cytoplasm-translocated GαS, causing enhanced response to IL-6 and driving premalignant HcPCs to fully established HCC, which provides mechanistic insight and a potential target for preventing hepatocarcinogenesis.

JMJD4-demethylated RIG-I prevents hepatic steatosis and carcinogenesis.

BACKGROUND: Hepatocarcinogenesis is driven by necroinflammation or metabolic disorders, and the underlying mechanisms remain largely elusive. We previously found that retinoic acid-inducible gene-I (RIG-I), a sensor for recognizing RNA virus in innate immune cells, is mainly expressed by parenchymal hepatocytes in the liver. However, its roles in hepatocarcinogenesis are unknown, which is intensively investigated in this study. METHODS: DEN-induced necroinflammation-driven hepatocarcinogenesis and STAM NASH-hepatocarcinogenesis were carried out in hepatocyte-specific RIG-I knockout mice. The post-translational modification of RIG-I was determined by mass spectrometry, and specific antibodies against methylated lysine sites and the RIG-I lysine mutant mice were constructed to identify the functions of RIG-I methylation. RESULTS: We interestingly found that DEN-induced hepatocarcinogenesis was enhanced, while NASH-induced hepatocarcinogenesis was suppressed by hepatocyte-specific RIG-I deficiency. Further, IL-6 decreased RIG-I expression in HCC progenitor cells (HcPCs), which then viciously promoted IL-6 effector signaling and drove HcPCs to fully established HCC. RIG-I expression was increased by HFD, which then enhanced cholesterol synthesis and steatosis, and the in-turn NASH and NASH-induced hepatocarcinogenesis. Mechanistically, RIG-I was constitutively mono-methylated at K18 and K146, and demethylase JMJD4-mediated RIG-I demethylation suppressed IL-6-STAT3 signaling. The constitutive methylated RIG-I associated with AMPKα to inhibit HMGCR phosphorylation, thus promoting HMGCR enzymatic activity and cholesterol synthesis. Clinically, RIG-I was decreased in human hepatic precancerous dysplastic nodules while increased in NAFLD livers, which were in accordance with the data in mouse models. CONCLUSIONS: Decreased RIG-I in HcPCs promotes necroinflammation-induced hepatocarcinogenesis, while increased constitutive methylated RIG-I enhances steatosis and NASH-induced hepatocarcinogenesis. JMJD4-demethylated RIG-I prevents both necroinflammation and NASH-induced hepatocarcinogenesis, which provides mechanistic insight and potential target for preventing HCC.

Discovery of a Trifluoromethoxy Cyclopentanone Benzothiazole Receptor-Interacting Protein Kinase 1 Inhibitor as the Treatment for Alzheimer's Disease.

Receptor-interacting protein kinase 1 (RIPK1) contributes to a broad set of inflammations and necroptosis in human diseases, which also plays an important role in the pathogenesis of Alzheimer's disease (AD). The inhibition of RIPK1 could be a novel strategy to improve cognitive function. SZM679, a highly specific RIPK1 inhibitor (Kd,RIPK1 = 8.6 nM, Kd,RIPK3 > 5000 nM), was developed by our group with superior high antinecroptotic activity (EC50 = 2 nM), and investigated to completely reverse the tumor necrosis factor-induced systemic inflammatory response syndrome. In a streptozocin-induced AD-like mouse model, behavioral tests showed that SZM679 apparently ameliorated learning and memory dysfunction. Nissl staining revealed that SZM679 improved neuronal loss. Moreover, the Tau hyperphosphorylation, neuroinflammation, and the RIPK1 phosphorylation level in the hippocampus and cortex were significantly decreased in the SZM679-treated group. Collectively, SZM679 represents a promising lead structure for the discovery of novel RIPK1 inhibitory anti-AD agents.

Methionine-Derived Organogels as Lubricant Additives Enhance the Continuity of the Oil Film through Dynamic Self-Healing Assembly.

(S)-2-((1-(Hexadecylamino)-4-(methylthio)-1-oxobutan-2-yl)carbamoyl)benzoic acid (HMTA) was efficiently synthesized and successfully applied as an additive to several types of blank lubricant oils. Initially, HMTA self-assembles to fibrous structures and traps blank lubricant oils to form gel lubricants. The prepared gel lubricants show thermo-reversible properties and enhanced lubricating performance by 3∼5-fold. X-ray photoelectron spectrometry of the metal surface and the quartz crystal microbalance illustrated that there are no obvious interactions between HMTA and the metal surface. The results of Fourier transform infrared spectroscopy and X-ray diffraction further confirm that inter/intro-molecular H-bonding interactions are the main driving force for the self-healing of HMTA. Finally, molecular dynamics (MD) simulations show that the number of noncovalent H-bonding interactions fluctuates with time, and this highly dynamic H-bonding network could regulate the self-assembly process and result in the self-healing property of the HMTA organogel, which is consistent with the results of the step-strain tests. Especially, the Hirshfeld independent gradient model method at the quantum level demonstrated that C8/C9 aromatics of 500SN have strong π-π stacking interactions with the aromatic heads of HMTA and van der Waals interactions with the hydrophobic tails of HMTA, which disrupt the self-assembly behavior of the 500SN model. Therefore, the calculation studies offer a rational explanation for the superior lubricant property of the PAO10 gel as compared to that for 500SN.

Peramivir, an Anti-Influenza Virus Drug, Exhibits Potential Anti-Cytokine Storm Effects.

Coronavirus Disease 2019 (COVID-19) infected by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been declared a public health emergency of international concerns. Cytokine storm syndrome (CSS) is a critical clinical symptom of severe COVID-19 patients, and the macrophage is recognized as the direct host cell of SARS-CoV-2 and potential drivers of CSS. In the present study, peramivir was identified to reduce TNF-α by partly intervention of NF-κB activity in LPS-induced macrophage model. In vivo, peramivir reduced the multi-cytokines in serum and bronchoalveolar lavage fluid (BALF), alleviated the acute lung injury and prolonged the survival time in mice. In human peripheral blood mononuclear cells (hPBMCs), peramivir could also inhibit the release of TNF-α. Collectively, we proposed that peramivir might be a candidate for the treatment of COVID-19 and other infections related CSS.

Garlic oil blocks tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis by inducing phase II drug-metabolizing enzymes.

Lung cancer caused one-quarter of all cancer deaths that was more than other cancers. Chemoprevention is a potential strategy to reducing lung cancer incidence and death, and the effective chemopreventive agents are needed. We investigated the efficacy and mechanism of garlic oil (GO), the garlic product, in the chemoprevention of tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung cancer in A/J mice and MRC-5 cell models in the present study. As a result, it was demonstrated that GO significantly inhibited the NNK-induced lung cancer in vivo and protected MRC-5 cells from NNK-induced cell damage. GO could induce the expressions of the phase II drug-metabolizing enzymes, including NAD(P)H: quinone oxidoreductase 1 (NQO-1), glutathione S-transferase alpha 1 (GSTA1), and antioxidative enzymes heme oxygenase-1 (HO-1). These results supported the potential of GO as a novel candidate agent for the chemoprevention of tobacco carcinogens induced lung cancer.

Biological Activity, Hepatotoxicity, and Structure-Activity Relationship of Kavalactones and Flavokavins, the Two Main Bioactive Components in Kava (Piper methysticum).

Kava (Piper methysticum Forst) is a popular and favorable edible medicinal herb which was traditionally used to prepare a nonfermented beverage with relaxant beneficial for both social and recreational purposes. Numerous studies conducted on kava have confirmed the presence of kavalactones and flavokawains, two major groups of bioactive ingredients, in this miraculous natural plant. Expectedly, both kavalactone and flavokawain components exhibited potent antianxiety and anticancer activities, and their structure-activity relationships were also revealed. However, dozens of clinical data revealed the hepatotoxicity effect which is indirectly or directly associated with kava consumption, and most of the evidence currently seems to point the compounds of flavokawains in kava were responsible. Therefore, our aim is to conduct a systematic review of kavalactones and flavokawains in kava including their biological activities, structure-activity relationships, and toxicities, and as a result of our systematic investigations, suggestions on kava and its compounds are supplied for future research.

Exposure to a mixture of cigarette smoke carcinogens disturbs gut microbiota and influences metabolic homeostasis in A/J mice.

An increased risk of developing lung cancer has been associated with exposure to cigarette smoke carcinogens and alteration in the gut microbiota. However, there is limited understanding about the impact of exposure to NNK and BaP, the two important components of cigarette smoke carcinogens, on gut microbiota in lung cancer. The present study characterized the influence of exposure to a mixture of NNK plus BaP on lung cancer, feces metabolite composition, and gut microbiota in the A/J mice. The A/J mice were administered NNK plus BaP, and the changes in gut microbiota and feces metabolic profiles were characterized using 16S rRNA gene sequencing and metabolomics, respectively. Results presented here illustrated that a mixture of NNK plus BaP exposure triggered lung carcinogenesis as shown by light microscopy and histopathological evaluation. 16S rRNA sequencing of gut microbiota indicated that exposure to NNK plus BaP could modified fecal bacterial composition. Elevated levels of Actinobacteria, Bifidobacterium, and Intestinimonas and reduced levels of Alistipes, Odoribacter, and Acetatifactor are associated with NNK plus BaP triggered lung cancer. In addition, metabolomics profile revealed the regulation of metabolism including purine metabolism, phenylalanine metabolism, primary bile acid biosynthesis, steroid hormone biosynthesis, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and others. In conclusion, the results provide some guidance for using gut microbes as biomarkers to assess the progression of lung cancer, and lead to interventional targets to control the development of the disease in the future.

Structure-based bioisosterism design of thio-benzoxazepinones as novel necroptosis inhibitors.

Necroptosis is reported to play a critical role in contributing to a variety of human pathologies. The benzoxazepinone GSK'772 is a potent necroptosis inhibitor optimized using a hit from a DNA-encoded library, which is currently in phase II clinical trials for psoriasis, rheumatoid arthritis, and ulcerative colitis. In the present study, the bioisosterism strategy was applied to replace the amide and benzene ring of GSK'772 based on the co-crystal structure of GSK'772 with its binding target RIPK1. As a result, the novel thio-benzoxazepinones exhibited higher anti-necroptosis activity in a human HT-29 cell necroptosis model. The effect on anti-necroptosis activity by the chirality was significantly reduced in the thio-benzoxazepinones, which was explained by the ligand conformation calculation. Among these analogues, compound 11 (S) and 12 (R) specifically inhibited necroptosis rather than apoptosis with EC50 values of 2.8 and 22.6 nM. They blocked necrosome formation by inhibiting the phosphorylation of RIPK1, RIPK3 and MLKL in necroptotic cells. Collectively, the highly potent thio-benzoxazepinones represent promising lead structures for further development of necroptosis-related diseases.

Novel dual-mode antitumor chlorin-based derivatives as potent photosensitizers and histone deacetylase inhibitors for photodynamic therapy and chemotherapy.

The combination of photodynamic therapy (PDT) and chemotherapy is a prospective strategy to improve antitumor efficacy. Herein, a series of novel cytotoxic chlorin-based derivatives as dual photosensitizers (PSs) and histone deacetylase inhibitors (HDACIs) were synthesized and investigated for biological activity. Among them, compound 15e showed definite HDAC2 and 10 inhibitory activities by up-regulating expression of acetyl-H4 and highest phototoxicity and dark-toxicity, which was more phototoxic than Talaporfin as a PS while with stronger dark-toxicity compared to vorinostat (SAHA) as a HDACI. The biological assays demonstrated that 15e was liable to enter A549 cells and localized in mitochondria, lysosomes, golgi and endoplasmic reticulum (ER) etc. multiple organelles, resulting in higher cell apoptosis rate and ROS production compared to Talaporfin. Moreover, it could induce tumor cell autophagy as a dual PS and HDACI. All results suggested that compound 15e could be applied as a potential dual cytotoxic drug for PDT and chemotherapy.

Design, synthesis and biological evaluation of novel 31-hexyloxy chlorin e6-based 152- or 131-amino acid derivatives as potent photosensitizers for photodynamic therapy.

This study aimed to improve the biological effectiveness and pharmacokinetic properties of chlorin e6, a second-generation photosensitizer (PS), for tumor photodynamic therapy (PDT). Herein, the novel 31-hexyloxy chlorin e6-based 152- or 131-amino acid derivatives 3a, 3b, 3c and 8 were synthesized and their photophysical properties and in vitro bioactivities such as phototoxicity against A549, HeLa and melanoma B16-F10 cells, reactive oxygen species (ROS) production and subcellular localization were evaluated. In addition, preferred target compounds were also investigated for their in vivo pharmacokinetic in SD rats and in vivo antitumor efficacies in C57BL/6 mice bearing melanoma B16-F10 cells. Apparently, simultaneous introduction of amino acid residue and n-hexyloxy chain in chlorin e6 made a significant improvement in photophysical properties, ROS production, in vitro and in vivo PDT efficacy. Encouragingly, all target compounds showed higher in vitro phototoxicity than Talaporfin, and that 3c (152-Lys) exhibited strongest phototoxicity and highest dark toxicity/phototoxicity ratio, followed by 8 (131-Asp), 3a (152-Asp) and 3b (152-Glu). Moreover, in vivo PDT antitumor efficacy of 3a, 3c and 8 was all better than that of Talaporfin, and that both 3c and 8 had stronger PDT antitumor efficiency than 3a. The overall results suggested that these novel 31-hexyloxy chlorin e6-based 152- or 131-amino acid derivatives, especially 3c and 8, might be potential antitumor candidate drugs for clinical treatment of melanoma by PDT.

Drug repurposing of anti-infective clinical drugs: Discovery of two potential anti-cytokine storm agents.

Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) has been widely spread in the world with a high mortality. Cytokine storm syndrome (CSS) and acute lung injury caused by SARS-CoV-2 infection severely threaten the patients. With the purpose to find effective and low-toxic drugs to mitigate CSS, entecavir and imipenem were identified to reduce TNF-α using a LPS-induced macrophage model from the anti-infective drug library. Entecavir and imipenem efficiently suppressed the release of inflammatory cytokines by partly intervention of NF-κB activity. The acute lung injury was also alleviated and the survival time was prolonged in mice. In addition, entecavir and imipenem inhibited the release of TNF-α and IL-10 in human peripheral blood mononuclear cells (hPBMCs). Collectively, we proposed that entecavir and imipenem might be candidates for the treatment of CSS.

Isoliquiritigenin Nanosuspension Enhances Cytostatic Effects in A549 Lung Cancer Cells.

Isoliquiritigenin, a flavonoid extracted from licorice root, has been shown to be active against most cancer cells; however, its antitumor activity is limited by its poor water solubility. The aim of this study was to develop a stable isoliquiritigenin nanosuspension for enhanced solubility and to evaluate its in vitro cytostatic activity in A549 cells. The nanosuspension of isoliquiritigenin was prepared through wet media milling with HPC SSL (hydroxypropyl cellulose-SSL) and PVP K30 (polyinylpyrrolidone-K30) as stabilizers, and the samples were then characterized according to particle size, zeta-potential, SEM (scanning electron microscopy), TEM (transmission electron microscopy), DSC (differential scanning calorimetry), XRPD (X-ray powder diffraction), FTIR (Fourier transform infrared spectroscopy), XPS (X-ray photoelectron spectroscopy), and in vitro release. The isoliquiritigenin nanosuspension prepared with HPC SSL and PVP K30 had particle sizes of 238.1 ± 4.9 nm and 354.1 ± 9.1 nm, respectively. Both nanosuspensions showed a surface charge of approximately - 20 mV and a lamelliform or ellipse shape. The dissolution of isoliquiritigenin from the 2 nanosuspensions was markedly higher than that of free isoliquiritigenin. In vitro studies on A549 cells indicated that the cytotoxicity and cellular uptake significantly improved after treatment with both nanosuspensions in comparison to the isoliquiritigenin solution. Furthermore, cell apoptosis analysis showed a 7.5 - 10-fold increase in the apoptosis rate induced by both nanosuspensions compared with pure drug. However, the cytotoxicity of pure drug and nanosuspension on normal cells (HELF) was lower, which indicated both isoliquiritigenin nanosuspensions have low toxicity to normal cells. Therefore, the isoliquiritigenin nanosuspension prepared with HPC SSL and PVP K30 as stabilizers may be a promising approach to improve the solubility and cytostatic activity of isoliquiritigenin.

Design, Synthesis and Biological Activity of (20S,21S)-7-Cyclohexyl-21-fluorocamptothecin Carbamates as Potential Antitumor Agents.

(20S,21S)-7-Cyclohexyl-21-fluorocamptothecin was discovered by a fluorine drug design strategy with potent antitumor activity and increased metabolic stability. In continuous efforts to find novel antitumor agents derived from natural product camptothecin, 20-carbamates of the active compound (20S,21S)-7-cyclohexyl-21-fluorocamptothecin have been designed and synthesized. Among them, one compound with the diethylamino group showed greater antiproliferative activity than the other 20-carbamate derivatives. The following biological activity assays indicated that the above compound is a valuable lead compound with excellent Topo I inhibitory activity and solution stability.