Insights into N6-methyladenosine and programmed cell death in cancer.

N6-methyladenosine (m6A) methylation, the most common form of internal RNA modification in eukaryotes, has gained increasing attention and become a hot research topic in recent years. M6A plays multifunctional roles in normal and abnormal biological processes, and its role may vary greatly depending on the position of the m6A motif. Programmed cell death (PCD) includes apoptosis, autophagy, pyroptosis, necroptosis and ferroptosis, most of which involve the breakdown of the plasma membrane. Based on the implications of m6A methylation on PCD, the regulators and functional roles of m6A methylation were comprehensively studied and reported. In this review, we focus on the high-complexity links between m6A and different types of PCD pathways, which are then closely associated with the initiation, progression and resistance of cancer. Herein, clarifying the relationship between m6A and PCD is of great significance to provide novel strategies for cancer treatment, and has a great potential prospect of clinical application.

Introduction of long non-coding RNAs to regulate autophagy-associated therapy resistance in cancer.

Autophagy is a lysosomal degradation pathway that depends on various evolutionarily conserved autophagy-related genes (ATGs). Dysregulation of autophagy plays an important role in the occurrence and development of cancer. Chemotherapy, targeted therapy, radiotherapy, and immunotherapy are important treatment options for cancer, which can significantly improve the survival rate of cancer patients. However, the occurrence of therapy resistance results in therapeutic failure and poor prognosis of cancer. Accumulating studies have found that long non-coding RNAs (lncRNAs) are well known as crucial regulators to control autophagy through regulating ATGs and autophagy-associated signaling pathways, including the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, ultimately mediating chemoresistance and radioresistance. Taken together, this review systematically summarizes and elucidates the pivotal role of lncRNAs in cancer chemoresistance and radioresistance via regulating autophagy. Understanding the specific mechanism of which may provide autophagy-related therapeutic targets for cancer in the future.

Intricate crosstalk between MYB and noncoding RNAs in cancer.

MYB is often overexpressed in malignant tumors and plays a carcinogenic role in the initiation and development of cancer. Deletion of the MYB regulatory C-terminal domain may be a driving mutation leading to tumorigenesis, therefore, different tumor mechanisms produce similar MYB proteins. As MYB is a transcription factor, priority has been given to identifying the genes that it regulates. All previous attention has been focused on protein-coding genes. However, an increasing number of studies have suggested that MYB can affect the complexity of cancer progression by regulating tumor-associated noncoding RNAs (ncRNAs), such as microRNAs, long-non-coding RNAs and circular RNAs. ncRNAs can regulate the expression of numerous downstream genes at the transcription, RNA processing and translation levels, thereby having various biological functions. Additionally, ncRNAs play important roles in regulating MYB expression. This review focuses on the intricate crosstalk between oncogenic MYB and ncRNAs, which play a pivotal role in tumorigenesis, including proliferation, apoptosis, angiogenesis, metastasis, senescence and drug resistance. In addition, we discuss therapeutic strategies for crosstalk between MYB and ncRNAs to prevent the occurrence and development of cancer.

Synthesis and bioassay of ß-(1,4)-D-mannans as potential agents against Alzheimer's disease.

AIM: Oligomannurarate 971 derived from a marine plant has shown neuroprotective effects. In this study we synthesized a series of truncated derivatives of the oligosaccharide, and investigated the effect of these derivatives against Aß peptide toxicity in vitro. METHODS: The sulfoxide method was applied to synthesize the derivatives. SH-SY5Y human neuroblastoma cells were treated with Aß1-40 (2 µmol/L), and the cell viability was detected using a CCK8 assay. RESULTS: A series of ß-(1,4)-D-mannosyl oligosaccharide, ranging from the disaccharide to the hexasaccharide, were synthesized. Addition of 10 µmol/L ß-(1,4)-D-mannobiose 6, ß-(1,4)-D-mannotriose 9 or ß-(1,4)-D-mannotetraose 12 in SH-SY5Y cells significantly attenuated Aß1-40-induced toxicity. The efficacies were similar to those caused by 10 µmol/L oligomannurarate 971 or alzhemed. Other oligosaccharides including oligomaltoses and oligocelluloses were less active. CONCLUSION: Synthetic homogeneous short chain ß-(1,4)-D-mannans shows neuroprotective effect against Aß peptide toxicity similar to that of heterogeneous oligomannurarate 971 and alzhemed.

Reconstruction of the free-field radiation from a vibrating structure based on measurements in a noisy environment.

In a noisy environment, the sound field of a source is composed of three parts, which are: The field that would be radiated by the target source into free space, the incoming field from disturbing sources or reflections, and the scattered field that is created by the incoming wave falling on the target source. To accurately identify the sound source with nearfield acoustic holography in that situation, the last two parts must be removed from the mixed field. In a previous study, a method for recovering the free sound field in a noisy environment was proposed based on the equivalent source method and measurements of pressure [J. Acoust. Soc. Am. 131(2), 1260-1270 (2012)]. In the present paper, that method was modified by allowing the input data to be measurements of particle velocity instead of pressure. An experiment was carried out to examine both the pressure- and velocity-based methods, and the performance of the two methods was compared. It was found that both methods are capable of reconstructing the free-field pressure radiated by the target source based on measurements made in a noisy environment, but the velocity-based method shows a large benefit in the reconstruction of the free-field particle velocity.

CCLab--a multi-objective genetic algorithm based combinatorial library design software and an application for histone deacetylase inhibitor design.

The introduction of the multi-objective optimization has dramatically changed the virtual combinatorial library design, which can consider many objectives simultaneously, such as synthesis cost and drug-likeness, thus may increase positive rates of biological active compounds. Here we described a software called CCLab (Combinatorial Chemistry Laboratory) for combinatorial library design based on the multi-objective genetic algorithm. Tests of the convergence ability and the ratio to re-take the building blocks in the reference library were conducted to assess the software in silico, and then it was applied to a real case of designing a 5×6 HDAC inhibitor library. Sixteen compounds in the resulted library were synthesized, and the histone deactetylase (HDAC) enzymatic assays proved that 14 compounds showed inhibitory ratios more than 50% against tested 3 HDAC enzymes at concentration of 20 µg/mL, with IC(50) values of 3 compounds comparable to SAHA. These results demonstrated that the CCLab software could enhance the hit rates of the designed library and would be beneficial for medicinal chemists to design focused library in drug development (the software can be downloaded at: http://202.127.30.184:8080/drugdesign.html).

Cellular senescence and hematological malignancies: From pathogenesis to therapeutics.

Cellular senescence constitutes a permanent state of cell cycle arrest in proliferative cells induced by different stresses. The exploration of tumor pathogenesis and therapies has been a research hotspot in recent years. Cellular senescence is a significant mechanism to prevent the proliferation of potential tumor cells, but it can also promote tumor growth. Increasing evidence suggests that cellular senescence is involved in the pathogenesis and development of hematological malignancies, including leukemia, myelodysplastic syndrome (MDS) and multiple myeloma (MM). Cellular senescence is associated with functional decline of hematopoietic stem cells (HSCs) and increased risk of hematological malignancies. Moreover, the bone marrow (BM) microenvironment has a crucial regulatory effect in the process of these diseases. The senescence-associated secretory phenotype (SASP) in the BM microenvironment establishes a protumor environment that supports the proliferation and survival of tumor cells. Therefore, a series of therapeutic strategies targeting cellular senescence have been gradually developed, including the induction of cellular senescence and elimination of senescent cells. This review systematically summarizes the emerging information describing the roles of cellular senescence in tumorigenesis and potential clinical applications, which may be beneficial for designing rational therapeutic strategies for various hematopoietic malignancies.

Aromatic beta-amino-ketone derivatives as novel selective non-steroidal progesterone receptor antagonists.

A novel class of non-steroidal progesterone receptor antagonists with aromatic beta-amino-ketone scaffold have been synthesized and characterized with high binding affinity and great selectivity for the cognate receptors. Among them, compound 22 was shown to be the most potent progesterone receptor antagonist in cotransfection assay and a murine model of ligand-induced decidualization.

Design, synthesis and biological evaluation of novel dual inhibitors of acetylcholinesterase and beta-secretase.

To explore novel effective drugs for the treatment of Alzheimer's disease (AD), a series of dual inhibitors of acetylcholineterase (AChE) and beta-secretase (BACE-1) were designed based on the multi-target-directed ligands strategy. Among them, inhibitor 28 exhibited good dual potency in enzyme inhibitory potency assay (BACE-1: IC(50)=0.567 microM; AChE: IC(50)=1.83 microM), and also showed excellent inhibitory effects on Abeta production of APP transfected HEK293 cells (IC(50)=98.7 nM) and mild protective effect against hydrogen peroxide (H(2)O(2))-induced PC12 cell injury. Encouragingly, intracerebroventricular injection of 28 into amyloid precursor protein (APP) transgenic mice caused a 29% reduction of Abeta(1-40) production. Therefore, 28 was demonstrated as a good lead compound for the further study and more importantly, the strategy of AChE and BACE-1 dual inhibitors might be a promising direction for developing novel drugs for AD patients.

ScafBank: a public comprehensive Scaffold database to support molecular hopping.

AIM: The search for molecules whose bioactivities are similar to those of given compounds or to optimize the initial lead compounds from high throughput screening has attracted increasing interest in recent years. Our goal is to provide a publically searchable database of scaffolds out from a large collection of existing chemical molecules. RESULTS: Although a number of in silico methods have emerged to facilitate this process, which has become known as "scaffold hopping" or "molecular hopping", there is an urgent need for a database system to provide such valuable data in the drug design field. Here we have systematically analyzed a collection of commercially available small molecule databases and a bioactive compound database to identify unique scaffolds and we have built a publically searchable database. The analysis of approximately 4,800,000 of these compounds identified 241,824 unique scaffolds, which are stored in a relational database (http://202.127.30.184:8080/db.html). Each entry in the database is associated with a molecular occurrence and includes its distribution of molecular properties, such as molecular weight, logP, hydrogen bond acceptor number, hydrogen bond donor number, rotatable bond number and ring number. More importantly, for scaffolds derived from the bioactive compounds database, it also contains the original compounds and their target information. CONCLUSION: This Web-based database system could help researchers in the fields of medicinal and organic chemistry to design novel molecules with properties similar to the original compounds, but built on novel scaffolds.

Structure-activity relationship of 39 analogs of laetispicine with antidepressant properties.

The natural product Laetispicine ( N -isobutyl-(3,4-methylendioxyphenyl)-2E, 4E, 9E-undecatrienoamide), was isolated from the Piper laetispicum C. DC and screened, for its antidepressant activity and antinociceptive effects. Structure-functional activities of five natural products indicated that biological activity is dependent on double bonds present within the benzene ring and a conjugated double bond located at positions 2-3 and 4-5 in the molecular structure. To further understand the structural-activity relationship of Laetispicine as a new potent and safe antidepressant, the structural-activity relationship of 39 analogs of Laetispicine were synthetized and tested in forced swimming tests in mice whilst also in protective effects against glutamate or H 2 O 2 induced apoptosis in PC12 cells. The results show that the compound 30 - N -isobutyl-11-(4-chlorophenyl) undeca-2E,4E,9E-trienamide exhibited the same activity as the parental compound Laetispicine, and furthermore, the effective dose of this compound is lower than Laetispicine. Therefore, the compound 30 might be a potentially useful therapy in the treatment of depression. For structure, the conjugated double bonds located at 2-3, 4-5 and isolated double bonds from benzene ring are necessary for the antidepressant activities no matter the different length of carbon chain; the isobutyl connected with acylamino also are necessary; and the benzodioxole moiety is replaceable, the halogen atom in phenyl ring at the para-position could enhance this kind of activity.

[Suitable oxygen concentration for rat model's hypoxic preconditioning].

OBJECTIVE: To study the suitable oxygen concentration in hypoxic preconditioning. METHODS: Short-term and long-term intermittent hypoxia modes were designed and the effects of various oxygen concentrations on body weight, blood oxygen saturation, swimming capability were analyzed. RESULTS: The rate of body weight gain in rat model decreased gradually when exposed to hypoxia environment for long time. When the concentration of oxygen changed from 15% to 8%, accompanied with the decreasing of oxygen concentration, a platform was observed in blood oxygen saturation of rat model after hypoxic preconditioning training. Rat swimming capability improved significantly. After trained in 10% hypoxia environment, the swimming capability of kunming mice improved obviously. CONCLUSION: Proper level of hypoxic preconditioning training could improve hypoxia tolerance and enhance the rat sport capability significantly. 15%-10% oxygen concentration range could be regarded as a helpful effective area for hypoxic preconditioning, 10% oxygen concentration might be the eligible concentration for hypoxic preconditioning training.

Design, synthesis, and evaluation of Leu*Ala hydroxyethylene-based non-peptide beta-secretase (BACE) inhibitors.

With the aim of developing small molecular non-peptide beta-secretase (BACE) inhibitors, Leu*Ala hydroxyethylene (HE) was investigated as a scaffold to design and synthesize a series of compounds. Taking advantage of efficient combinatorial synthesis approaches and molecular modeling, extensive structure-activity relationship (SAR) studies were carried out on the N- and C-terminal residues of the Leu*Ala HE scaffold. Isobutyl amine was found to be an optimal C-cap, and suitable hydroxylalkylamines at the 3-position and nitro or methyl(methylsulfonyl)amine at the 5-position of isophthalamide as the N-terminus could form additional hydrogen bonds with BACE active sites and help improve potency. Many new potent non-peptide BACE inhibitors were identified in this study. Among them, compounds 37 and 44 exhibited excellent enzyme-inhibiting potency, comparable to that of OM99-2, and obvious inhibitory effects in cell-based assay with low molecular weights (<600).