Targeting cancer epigenetic pathways with small-molecule compounds: Therapeutic efficacy and combination therapies.

Epigenetics mainly refers to covalent modifications to DNA or histones without affecting genomes, which ultimately lead to phenotypic changes in cells or organisms. Given the abundance of regulatory targets in epigenetic pathways and their pivotal roles in tumorigenesis and drug resistance, the development of epigenetic drugs holds a great promise for the current cancer therapy. However, lack of potent, selective, and clinically tractable small-molecule compounds makes the strategy to target cancer epigenetic pathways still challenging. Therefore, this review focuses on epigenetic pathways, small molecule inhibitors targeting DNA methyltransferase (DNMT) and small molecule inhibitors targeting histone modification (the main regulatory targets are histone acetyltransferases (HAT), histone deacetylases (HDACs) and histone methyltransferases (HMTS)), as well as the combination strategies of the existing epigenetic therapeutic drugs and more new therapies to improve the efficacy, which will shed light on a new clue on discovery of more small-molecule drugs targeting cancer epigenetic pathways as promising strategies in the future.

Targeting cholesterol metabolism in Cancer: From molecular mechanisms to therapeutic implications.

Cholesterol is an essential component of cell membranes and helps to maintain their structure and function. Abnormal cholesterol metabolism has been linked to the development and progression of tumors. Changes in cholesterol metabolism triggered by internal or external stimuli can promote tumor growth. During metastasis, tumor cells require large amounts of cholesterol to support their growth and colonization of new organs. Recent research has shown that cholesterol metabolism is reprogrammed during tumor development, and this can also affect the anti-tumor activity of immune cells in the surrounding environment. However, identifying the specific targets in cholesterol metabolism that regulate cancer progression and the tumor microenvironment is still a challenge. Additionally, exploring the potential of combining statin drugs with other therapies for different types of cancer could be a worthwhile avenue for future drug development. In this review, we focus on the molecular mechanisms of cholesterol and its derivatives in cell metabolism and the tumor microenvironment, and discuss specific targets and relevant therapeutic agents that inhibit aspects of cholesterol homeostasis.

1-Chloro-1H-1,2,3-benzotriazole.

The title compound, C6H4ClN3, is essentially planar, with a maximum deviation of 0.007 (3) Å. In the crystal, a short contact of 2.818 (3) Šis observed between N and Cl atoms of adjacent mol-ecules.

Unravelling the roles of Autophagy in OSCC: A renewed perspective from mechanisms to potential applications.

Oral squamous cell carcinoma (OSCC) is associated with a low survival rate and a high disability rate, making it a serious health burden, particularly in Southeast Asian countries. Therefore, improvements in the diagnosis, treatment, and prognosis prediction of OSCC are highly warranted. Autophagy has a significant impact on cancer development. Studies on autophagy in various human cancers have made outstanding contributions; however, the relationship between autophagy and OSCC remains to be explored. This review highlights the roles of autophagy in OSCC and discusses the relationship between autophagy and Epithelial-mesenchymal transition. Considering the lack of OSCC biomarkers, we focus on the studies involving OSCC-related bioinformatics analysis and molecular targets. Based on some classical targets, we summarize several key autophagy-related biomarkers with a considerable potential for clinical application, which may become the hotspot of OSCC research. In conclusion, we elaborate on the interrelationship between autophagy and OSCC and highlight the shortcomings of current studies to provide insights into the potential clinical strategies.

Molecular-docking-guided design, palladium-catalyzed synthesis and anticancer activity of paclitaxel-benzoxazoles hybrids.

A series of new paclitaxel-benzoxazoles hybrids were designed based on both the molecular docking mode of beta-tubulin with paclitaxel derivatives (7a and 7g), and the activity-structure relationship of C-13 side chain in paclitaxel. Palladium-catalyzed direct Csp2-H arylation of benzoxazoles with different aryl-bromides was used as the key synthetic strategy for the aryl-benzoxazoles moieties in the hybrids. Twenty-six newly synthesized hybrids were screened for their antiproliferative activity against human cancer cell lines such as human breast cancer cells (MDA-MB-231) and liver hepatocellular cells (HepG2) by the MTT assay and results were compared with paclitaxel. Interestingly, most hybrids (7a-7e, 7i, 7k, 7l, 7A, 7B, 7D and 7E) showed significantly active against both cell lines at concentration of 50 µM, which indicated that the hybrid strategy is effective to get structural simplified paclitaxel analogues with high anti-tumor activity.

Taccalonolides: Structure, semi-synthesis, and biological activity.

Microtubules are the fundamental part of the cell cytoskeleton intimately involving in cell proliferation and are superb targets in clinical cancer therapy today. Microtubule stabilizers have become one of the effectively main agents in the last decades for the treatment of diverse cancers. Taccalonolides, the highly oxygenated pentacyclic steroids isolated from the genus of Tacca, are considered a class of novel microtubule-stabilizing agents. Taccalonolides not only possess a similar microtubule-stabilizing activity as the famous drug paclitaxel but also reverse the multi-drug resistance of paclitaxel and epothilone in cellular and animal models. Taccalonolides have captured numerous attention in the field of medicinal chemistry due to their variety of structures, unique mechanism of action, and low toxicity. This review focuses on the structural diversity, semi-synthesis, modification, and pharmacological activities of taccalonolides, providing bright thoughts for the discovery of microtubule-stabilizing drugs.

Targeting Autophagy with Natural Compounds in Cancer: A Renewed Perspective from Molecular Mechanisms to Targeted Therapy.

Natural products are well-characterized to have pharmacological or biological activities that can be of therapeutic benefits for cancer therapy, which also provide an important source of inspiration for discovery of potential novel small-molecule drugs. In the past three decades, accumulating evidence has revealed that natural products can modulate a series of key autophagic signaling pathways and display therapeutic effects in different types of human cancers. In this review, we focus on summarizing some representative natural active compounds, mainly including curcumin, resveratrol, paclitaxel, Bufalin, and Ursolic acid that may ultimately trigger cancer cell death through the regulation of some key autophagic signaling pathways, such as RAS-RAF-MEK-ERK, PI3K-AKT-mTOR, AMPK, ULK1, Beclin-1, Atg5 and p53. Taken together, these inspiring findings would shed light on exploiting more natural compounds as candidate small-molecule drugs, by targeting the crucial pathways of autophagy for the future cancer therapy.

8ß-Acet-oxy-14α-benzo-yloxy-N-methyl-13ß,15α-dihy-droxy-1α,6α,16ß-trimeth-oxy-4ß-(meth-oxy-meth-yl)aconitane: hypaconitine isolated from 'fuzi'.

The title compound, C(33)H(45)NO(10), has an aconitine carbon skeleton with four six-membered rings and two five-membered rings. The five-membered rings adopt envelope configurations and the six-membered N-containing heterocyclic ring displays a chair conformation. Two intra-molecular O-H⋯O hydrogen bonds occur.

(25R)-5a-Spiro-stane-3,12-dione.

The title compound, C(27)H(40)O(4), was obtained from the oxidation of (25R)-3b-hydr-oxy-5a-spiro-stan-12-one (Hecogenin) by Jone's reagent. The mol-ecule contains six alicyclic and heterocyclic rings, all trans-fused, among which four six-membered rings adopt similar chair conformations while two five-membered rings assume an envelope conformation.

Lewis acid-mediated skeleton transformation of Euphorbia diterpenes: From lathyrane to euphoractane and myrsinane.

Natural euphoractane and myrsinane diterpene skeletons, together with an unnatural 5/7/7/4 fused-ring diterpene skeleton were furnished via BF3·Et2O-mediated transformation of lathyrane-type diterpene, Euphorbia factor L1. The skeleton transformation process was mainly involved in the cascade oxirane-opening (cyclopropane-opening)/oxe-Micheal addition reaction. The structures of three diterpenes were confirmed by comprehensive spectra analysis and single crystals X-ray diffraction. Current results proved the biogenesis pathway between lathyrane with euphoractane and myrsinane by chemical transformation for the first time.

Recent advances in microtubule-stabilizing agents.

Highly dynamic mitotic spindle microtubules are superb therapeutic targets for a group of chemically diverse and clinically successful anticancer drugs. Microtubule-targeted drugs disrupt microtubule dynamics in distinct ways, and they are primarily classified into two groups: microtubule destabilizing agents (MDAs), such as vinblastine, colchicine, and combretastatin-A4, and microtubule stabilizing agents (MSAs), such as paclitaxel and epothilones. Systematic discovery and development of new MSAs have been aided by extensive research on paclitaxel, yielding a large number of promising anticancer compounds. This review focuses on the natural sources, structural features, mechanisms of action, structure-activity relationship (SAR) and chemical synthesis of MSAs. These MSAs mainly include paclitaxel, taccalonolides, epothilones, FR182877 (cyclostreptin), dictyostatin, discodermolide, eleutherobin and sarcodictyins, zampanolide, dactylolide, laulimalides, peloruside and ceratamines from natural sources, as well as small molecular microtubule stabilizers obtained via chemical synthesis. Then we discuss the application prospect and development of these anticancer compounds.

Synthesis and characterization of HPMC derivatives as novel duodenum-specific coating agents.

HPMC (Hydroxypropyl methylcellulose) was chemically modified, using maleic anhydrides, to obtain pH-sensitive HPMCAM (Hydroxypropyl methylcellulose acetate maleate) polymers for use as novel duodenum-specific coating agents. The pharmaceutical properties of HPMCAM, such as film forming, acid values, pH-sensitive values, water vapor permeability, tensile strength and Tg, were investigated, and found to show good film forming properties. The pH-sensitive values were 3.0 to 3.7. In vitro results demonstrate that HPMCAM could completely suppress drug release within 2h in a simulated gastric fluid (pH 1.2) and rapidly release the drug in a simulated pathological duodenal fluid (pH 3.4). These results indicate that HPMCAM might be a useful material for a duodenum-specific drug delivery system.

Ultrasound-assisted extraction of total flavonoids from Aconitum gymnandrum.

BACKGROUND: Aconitum gymnandrum is a Chinese traditional herb used as carminative and analgesic. In this study, A. gymnandrum was used as an experimental matrix. MATERIALS AND METHODS: Optimized ultrasonic extraction technology of total flavonoids from the A. gymnandrum Maxim was studied by using the methodology of single factor and orthogonal design to study the effects of operation conditions, such as ethanol content, ultrasonic wave power, temperature, ultrasonic wave radiation time, and the ratio of sample weight to solvent volume. RESULT: THROUGH THE ORTHOGONAL EXPERIMENT, THE OPTIMAL EXTRACTION CONDITIONS WERE DETERMINED AS FOLLOWS: Ultrasonic power 100 W, ultrasonic temperature 45°C, 60% ethyl alcohol, extraction time 30 min, and solid-liquid ratio 1:20. CONCLUSION: Under the optimum parameters, the extraction ratio of total flavonoids from the A. gymnandrum Maxim is about 1.278%.