Oncobiome at the Forefront of a Novel Molecular Mechanism to Understand the Microbiome and Cancer.

The microbiome comprises all the genetic material within a microbiota, that represents tenfold higher than that of our cells. The microbiota it includes a wide variety of microorganisms such as bacteria, viruses, protozoans, fungi, and archaea, and this ecosystem is personalized in any body space of every individual. Balanced microbial communities can positively contribute to training the immune system and maintaining immune homeostasis. Dysbiosis is a change in the normal microbiome composition that can initiate chronic inflammation, epithelial barrier breaches, and overgrowth of harmful bacteria. The next-generation sequencing methods have revolutionized the study of the microbiome. Bioinformatic tools to manage large volumes of new information, it became possible to assess species diversity and measure dynamic fluctuations in microbial communities. The burden of infections that are associated to human cancer is increasing but is underappreciated by the cancer research community. The rich content in microbes of normal and tumoral tissue reflect could be defining diverse physiological or pathological states. Genomic research has emerged a new focus on the interplay between the human microbiome and carcinogenesis and has been termed the 'oncobiome'. The interactions among the microbiota in all epithelium, induce changes in the host immune interactions and can be a cause of cancer. Microbes have been shown to have systemic effects on the host that influence the efficacy of anticancer drugs. Metagenomics allows to investigate the composition of microbial community. Metatranscriptome analysis applies RNA sequencing to microbial samples to determine which species are present. Cancer can be caused by changes in the microbiome. The roles of individual microbial species in cancer progression have been identified long ago for various tissue types. The identification of microbiomes of drug resistance in the treatment of cancer patients has been the subject of numerous microbiome studies. The complexity of cancer genetic alterations becomes irrelevant in certain cancers to explain the origin, the cause or the oncogenic maintenance by the oncogene addiction theory.

DNA methylation of leptin and adiponectin promoters in children is reduced by the combined presence of obesity and insulin resistance.

OBJECTIVE: Epigenetic alterations have been suggested to be associated with obesity and related metabolic disorders. Here we examined the correlation between obesity and insulin resistance with the methylation frequency of the leptin (LEP) and adiponectin (ADIPOQ) promoters in obese adolescents with the aim to identify epigenetic markers that might be used as tools to predict and follow up the physiological alterations associated with the development of the metabolic syndrome. SUBJECTS: One hundred and six adolescents were recruited and classified according to body mass index and homeostasis model of assessment-insulin resistance index. The circulating concentrations of leptin, adiponectin and of several metabolic markers of obesity and insulin resistance were determined by standard methods. The methylation frequency of the LEP and ADIPOQ promoters was determined by methylation-specific PCR (MS-PCR) in DNA obtained from peripheral blood samples. RESULTS: Obese adolescents without insulin resistance showed higher and lower circulating levels of, respectively, leptin and adiponectin along with increased plasmatic concentrations of insulin and triglycerides. They also exhibited the same methylation frequency than lean subjects of the CpG sites located at -51 and -31 nt relative to the transcription start site of the LEP gene. However, the methylation frequency of these nucleotides dropped markedly in obese adolescents with insulin resistance. We found the same inverse relationship between the combined presence of obesity and insulin resistance and the methylation frequency of the CpG site located at -283 nt relative to the start site of the ADIPOQ promoter. CONCLUSIONS: These observations sustain the hypothesis that epigenetic modifications might underpin the development of obesity and related metabolic disorders. They also validate the use of blood leukocytes and MS-PCR as a reliable and affordable methodology for the identification of epigenetic modifications that could be used as molecular markers to predict and follow up the physiological changes associated with obesity and insulin resistance.

Braf V600E mutation in melanoma: translational current scenario.

Melanoma was one of the translational cancer examples in clinic, including target therapy related to specific biomarkers impacting in the outcome of melanoma patients. Melanomagenesis involved a wide variety of mutations during his evolution; many of these mutated proteins have a kinase activity. One of the most cited proteins in melanoma is BRAF (about 50-60 % of melanomas harbors activating BRAF mutations), for these the most common is a substitution of valine to glutamic acid at codon 600 (p.V600E). Therefore, the precise identification of this underlying somatic mutation is essential; knowing the translational implications has opened a wide view of melanoma biology and therapy.

Identification of two novel Trichomonas vaginalis eif-5a genes.

The eukaryotic translation initiation factor 5A (eIF-5A) is highly conserved and is the only protein that is known to contain the unique and essential amino acid residue hypusine. Synthesis of hypusine is essential for the function of eIF5A in eukaryotic cell proliferation and survival. In this study, we identified two novel eukaryotic translation initiation factor 5A (eIF-5A) genes in Trichomonas vaginalis. The tveif-5a1 and tveif-5a2 putative genes were localized in different contigs, both containing ORFs encoding proteins of 168 amino acids that share high sequence identity with eIF-5A sequences from other eukaryotic organisms. A phylogenetic tree constructed with TveIF-5A1 and TveIF-5A2 from T. vaginalis and 13 other eIF-5A sequences of eukaryotic and archaebacterial origin revealed that both trichomonal TveIF-5As show the highest degree of similarity to bacteria. Using an anti-TveIF-5A antibody, we detected two protein bands and spots of 19 and 20kDa with isoelectric points (pI) of 5.2 and 5.5, respectively, by one and two-dimensional Western blot assays. In addition, we used reverse transcription polymerase chain reaction (RT-PCR) to demonstrate that both of these tveif-5a genes are expressed in T. vaginalis. Immunofluorescence assays showed that the TveIF-5A protein was dispersed throughout the parasite cytoplasm. In conclusion, T. vaginalis has two eif-5a genes, and both genes are expressed as highly conserved proteins of 19kDa, which are localized in the cytoplasm of this parasite.

Entamoeba histolytica: structural and functional analysis of the Ehadh112 gene promoter.

The Entamoeba histolytica Ehcp112 and Ehadh112 genes that encode the EhCPADH complex are separated by a non-coding 188pb region. Their proximity suggests a coordinated expression regulation for both genes. Here, we studied the structure and function of 996 bp (p996CAT) upstream the ATG start codon of the Ehadh112 gene. The p996CAT plasmid drove CAT transcription with a 78% of the activity showed by actin promoter. Deletion of 330 bp at the 5' end of p966CAT to produce the p776CAT plasmid, decreased activity to 40% in relation to actin promoter and to 50% of p996CAT, suggesting the presence of a silencer in this region. Interestingly, deletion of other 297 bp to the p776CAT to generate the p469CAT plasmid, augmented activity in 2.5-fold compared with p776CAT construction, showing the presence of a proximal enhancer promoter. Transcription initiation sites (-69 and -150 bp), TATA like box, GAAC, and Inr elements, as well as putative DNA binding motifs, were mapped in the -1 to -469 bp core promoter region.

The Entamoeba histolytica Ehcp112 gene has a distal and weak promoter.

Ehcp112 encodes the Entamoeba histolytica EhCP112 cysteine protease that is part of the EhCPADH complex. By in silico analysis we identified putative transcription factor-binding sites along 837 bp upstream the Ehcp112 gene ATG codon. A TATA-like motif (TATATAAA) was located at -36 to -29 bp, a GAAC box (GAACC) was found at -10 to -14 bp and an Inr sequence (TTCAAC) at -8 to -2 bp. These tripartite promoter elements are in non-canonical positions, downstream the transcription initiation site (-280 bp). We cloned four Ehcp112 promoter fragments in pBSCAT-ACT plasmid to obtain pI (355 bp), pII (681 bp), pIII (833 bp), and pIV (554 bp) constructs. In transfected trophozoites, only pIII drove CAT activity with 44% efficiency in relation to actin promoter activity. Our results showed the presence of a distal and weak promoter in the Ehcp112 gene. The active DNA region is inside the open reading frame of the Ehrab B gene, suggesting that expression of both genes could be coordinately regulated.