Comparative modeling of 25-hydroxycholesterol-7α-hydroxylase (CYP7B1): ligand binding and analysis of hereditary spastic paraplegia type 5 CYP7B1 mutations

CYP7B1 mutations have been linked directly with the neurodegenerative disease hereditary spastic paraplegia (HSP), with mutations in the CYP7B1 gene identified as being directly responsible for autosomal recessive HSP type 5A (SPG5). To evaluate the potential impact of CYP7B1 mutations identified in SPG5 on binding and protein function, a comparative model of cytochrome P450 7B1 (CYP7B1) was constructed using human CYP7A1 as a template during model construction. The secondary structure was predicted using the PSIPRED and GOR4 prediction methods, the lowest energy CYP7B1 model was generated using MOE, and then this model was assessed in terms of stereochemical quality and the side chain environment using RAMPAGE, Verify3D and ProSA. Evaluation of the active site residues of the CYP7B1 model and validation of the active site architecture were performed via molecular docking experiments: the docking of the substrates 25-hydroxycholesterol and 27-hydroxycholesterol and the inhibitor 3α-Adiol identified structurally and functionally important residues. Mutational analysis of CYP7B1 amino acid mutations related to hereditary spastic paraplegia type 5 considered phosphorylation, ligand/substrate binding and the structural roles of mutated amino acid residues, with R112, T297 and S363 mutations expected to have a direct impact on ligand binding, while mutations involving R417 would indirectly affect ligand binding as a result of impairment in catalytic function.     

Modulatory roles of microRNAs in the regulation of different signalling pathways in large bowel cancer stem cells

There are emerging data to suggest that microRNAs (miRNAs) have significant roles in regulating the function of normal cells and cancer stem cells (CSCs). This review aims to analyse the roles of miRNAs in the regulation of colon CSCs through their interaction with various signalling pathways. Studies showed a large number of miRNAs that are reported to be deregulated in colon CSCs. However, few of the studies available were able to outline the function of miRNAs in colon CSCs and uncover their signalling pathways. From those miRNAs, which are better described, miR‐21 followed by miR‐34, miR‐200 and miR‐215 are the most reported miRNAs to have roles in colon CSC regulation. In particular, miRNAs have been reported to regulate the stemness features of colon CSCs mainly via Wnt/B‐catenin and Notch signalling pathways. Additionally, miRNAs have been reported to act on processes involving CSCs through cell cycle regulation genes and epithelial–mesenchymal transition. The relative paucity of data available on the significance of miRNAs in CSCs means that new studies will be of great importance to determine their roles and to identify the signalling pathways through which they operate. Such studies may in future guide further research to target these genes for more effective cancer treatment. miRNAs were shown to regulate the function of cancer stem cells in large bowel cancer by targeting a few key signalling pathways in cells.     

GAEC1 mutations and copy number aberration is associated with biological aggressiveness of colorectal cancer

GAEC1 (gene amplified in oesophageal cancer 1) is a transforming oncogene with tumorigenic potential observed in both oesophageal squamous cell carcinoma and colorectal cancer. Nonetheless, there has been a lack of study done on this gene to understand how this gene exert its oncogenic properties in cancer. This study aims to identify novel mutation sites in GAEC1. To do so, seventy-nine matched colorectal cancers were tested for GAEC1 mutation via Sanger sequencing. The mutations noted were investigated for the correlations with the clinicopathological parameters of the patients with the cancer. Additionally, GAEC1 copy number aberration (CNA), mRNA and protein expression were determined with the use of droplet digital (dd) polymerase chain reaction (PCR), real-time PCR and Western blot (confirmed with immunofluorescence analysis). GAEC1 mutation was noted in 8.8% (n?=?7/79) of the cancer tissues including one missense mutation, four loss of heterozygosity (LOH) and two substitutions. These mutations were significantly associated with cancer perforation (p?=?0.021). GAEC1 mutation is frequently associated with increased GAEC1 protein expression. Nevertheless, GAEC1 mRNA and protein are only weakly associated. Taken together, GAEC1 mutation affects GAEC1 expression and is associated with poorer clinical outcomes. This further strengthens the role of GAEC1 as an oncogene.     

Identification of newly established <Emphasis Type="Italic">Spodoptera littoralis</Emphasis> cell lines by two DNA barcoding markers

Cell line authentication is crucial in determining the identity of cell lines and detecting any cross-contamination. The identity of three newly established Spodoptera littoralis cell lines (Spli-C, Spli-B, and Spli-S) was confirmed by DNA fingerprinting. In this study, we used two universal primers sets to amplify two DNA fragments in different positions in the mitochondrial cytochrome C oxidase 1 gene (COI). The PCR reaction succeeded in amplifying two target DNA amplicons. The first amplicon had ~650 bp, while the second had ~410 bp. By comparing the obtained informative sequences with those in the GenBank sequence database, the results showed 100% similarity between the S. littoralis cell lines and their host. The same similarity ratio was observed between the Sf21, Tni, and Cp cell lines, which are used widely, and their hosts. The informative sequences were then used for phylogenetic analyses. In addition to the high efficiency of this technique, it showed high reproducibility in two different laboratories. DNA barcoding using the two sets of the universal primers used in this study can be a fast and a reliable method for insect cell line identification.     

Molecular docking analysis of an isoflavone derivative with the protein phosphatase 1 from Leishmania donovani

Leishmaniasis is one of the most neglected diseases with high morbidity and mortality rate. Severe side effects with existing drug and lack of proper vaccine encouraged us to design alternative models to combat the disease. We showed that PP1 of Leishmania donovani mediates immunomodulation in host macrophages needed for parasite survival. Therefore, it is of interest to report the molecular docking analysis of 512 isoflavone derivatives with the phosphatase 1 protein from Leishmania donovani to highlight compound 362 (5-hydroxy-5-{9-[2-methoxy-2-(2-methylfuran-3-yl) ethyl]-1H, 3H, 4H, 10bH-pyrano[4,3-c]chromen-3-yl}pentanoic acid) having good binding features and acceptable ADMET properties for further consideration.