FJX1 as a candidate diagnostic and prognostic serum biomarker for colorectal cancer.

PURPOSE: Colorectal cancer (CRC) is one of the most common cancer worldwide. It is essential to identify non-invasive diagnostic and prognostic biomarkers of CRC. The aim of the present study was to screen candidate biomarkers in diagnosis and prognosis of CRC based on a novel strategy. MATERIALS AND METHODS: The expression level of gene higher in cancer than in adjacent non-cancer tissue was defined as "positive", and the top 10% genes with "positive rate" were filtered out as candidate diagnostic biomarkers in four Gene Expression Omnibus (GEO) datasets. Then, the prognostic value of candidate biomarkers was estimated Cox regression analysis. Moreover, the concentration of biomarker in serum was detected in CRC patients. RESULTS: Eighteen candidate biomarkers were identified with efficient diagnostic value in CRC. As a prognostic biomarker, FJX1 (four-jointed box kinase 1) showed a good performance in predicting overall survivals in CRC patients. In serum levels, FJX1 showed high sensitivity and specificity in distinguishing CRC patients from controls, and the concentration of serum FJX1 was associated with distant metastasis in CRC. In addition, serum FJX1 was significantly decreased after surgery in CRC patients. Compared with traditional CRC biomarkers CEA and CA 19-9, FJX1 still showed good efficiency in diagnosis and prognosis. Moreover, inhibition of FJX1 expression by siRNA or neutralization of secreted FJX1 by antibody could suppress cell proliferation and migration in vitro. CONCLUSION: Our findings provided a novel strategy to identify diagnostic biomarkers based on public datasets, and suggested that FJX1 was a candidate diagnostic and prognostic biomarker in CRC patients.

Analysis of culturable microbiota present in the stomach of children with gastric symptoms.

Despite extensive studies on the gastric microbiota, including Helicobacter pylori and non-H. pylori, the bacterial composition in children remains unknown. In this study, we analyzed the culturable gastric bacteria in stomach biopsies from 346 children aged 1-15 years affected by gastric diseases. H. pylori and non-H. pylori were identified by specific PCR and 16S rDNA sequencing, respectively. Antibiotic susceptibilities of H. pylori and non-H. pylori were tested by the E-test and disk diffusion methods, respectively. Rapid diagnosis was also performed by H. pylori-specific PCR. Twenty-two H. pylori strains were obtained from culture, and 92 biopsies were positive by H. pylori-specific PCR. The positive rate was higher in boys (40.3%) than in girls (23.3%) (P = 0.001). Resistance rates of 22 H. pylori strains were as follows: metronidazole, 86.4%; tetracycline, 22.7%; amoxicillin, 22.7%; levofloxacin, 31.8%; clarithromycin, 36.4%. Ten isolates were multidrug-resistant. Additionally, among 366 non-H. pylori strains, 204 exhibited urease activity. Non-H. pylori resistance rates were as follows: metronidazole, 94.8%; tetracycline, 26.2%; amoxicillin, 42.6%; levofloxacin, 15.3%; clarithromycin, 46.7%. Our results showed that children with gastric disorders harbor stomach bacteria with urease activity or nitrate reductase activity. Further studies will determine the effects of non-H. pylori bacteria in gastric diseases.

LmxMPK4, a mitogen-activated protein (MAP) kinase homologue essential for promastigotes and amastigotes of Leishmania mexicana.

BACKGROUND: Leishmania parasites undergo profound morphological and biochemical changes while passing through their life cycle. Protein kinases have been shown to be involved in the differentiation from the extracellular flagellated promastigotes to the intracellular "non-flagellated" amastigotes and vice versa. Moreover, these enzymes are likely involved in the regulation of the proliferation of the different life stages. RESULTS: Here, we characterize LmxMPK4, a mitogen-activated protein (MAP) kinase homologue from Leishmania mexicana. The kinase reveals all sequence motifs for classification as a MAP kinase. LmxMPK4 proved to be active as a recombinant protein. The kinase is expressed in promastigotes and amastigotes. It was impossible to generate homozygous gene deletion mutants for LmxMPK4 in promastigotes. Moreover, amastigotes bearing only an episomal copy of the gene stably retained LmxMPK4 over a prolonged period without antibiotic pressure in infected mice. CONCLUSION: LmxMPK4 is essential for promastigotes and amastigotes of Leishmania. It shows significant amino acid sequence divergence to mammalian MAP kinases. Thus, LmxMPK4 is a promising new drug target.

Identification of mitogen-activated protein kinase homologues from Leishmania mexicana.

Mitogen-activated protein kinases are key-regulatory elements in the differentiation, proliferation, apoptosis and stress response of eukaryotic cells. Our recent identification of a mitogen-activated protein kinase homologue in Leishmania mexicana which is essential for the proliferation of the amastigote stage of the parasite living in the parasitophorous vacuole of the infected macrophage prompted us to screen the genome of L. mexicana for additional mitogen-activated protein kinase homologues using degenerate oligonucleotide primers in a polymerase chain reaction amplification approach. We cloned and sequenced the genes for eight new mitogen-activated protein kinase homologues which were subsequently shown to be present in one copy per haploid genome. The mRNA levels of the kinases varied significantly in pro- and amastigote life stages of the parasite. We used the structural information of the p38 stress-activated protein kinase, which belongs to the family of mitogen-activated protein kinases, for the alignment of the deduced proteins and the verification of the predicted secondary structure elements. All new mitogen-activated protein kinases reveal the typical 12 subdomain primary structure, the conserved residues characterising serine/threonine protein kinases and the characteristic TXY motif in the phosphorylation lip. Typical features of some of the molecules are amino acid insertions between the subdomains and long carboxy-terminal amino acid extensions carrying putative src-homology 3-binding motifs.