Oncology indispensably leads us to personalized medicine, which allows an individual approach to be taken with each patient. Personalized oncology is based on pharmacogenomics and the effect of genetic differences in individuals (germline and somatic) on the way cancer patients respond to chemotherapeutics. Biomarkers detected using molecular biology tools allow the molecular characterization of cancer signatures and provide information relevant for personalized treatment. Biomarkers can be divided into two main subgroups: prognostic and predictive. The aim of the application of prognostic biomarkers, which provide information on the overall cancer outcome in patients, is to facilitate cancer diagnosis, usually with no need for putting invasive methods into use. Predictive biomarkers help to optimize therapy decisions, as they provide information on the likelihood of response to a given chemotherapeutic. Among the prognostic factors that identify patients with different outcome risks (e.g., recurrence of the disease), the following factors can be distinguished: somatic and germline mutations, changes in DNA methylation that lead to the enhancement or suppression of gene expression, the occurrence of elevated levels of microRNA (miRNA) capable of binding specific messenger RNA (mRNA) molecules, which affects gene expression, as well as the presence of circulating tumor cells (CTCs) in blood, which leads to a poor prognosis for the patient. Biomarkers for personalized oncology are used mainly in molecular diagnostics of chronic myeloid leukemia, colon, breast and lung cancer, and recently in melanoma. They are successfully used in the evaluation of the benefits that can be achieved through targeted therapy or in the evaluation of toxic effects of the chemotherapeutic used in the therapy.

The low levels of CFTR gene expression and paucity of CFTR protein in human airway epithelial cells are not easily reconciled with the pivotal role of the lung in cystic fibrosis pathology. Previous data suggested that the regulatory mechanisms controlling CFTR gene expression might be different in airway epithelium in comparison to intestinal epithelium where CFTR mRNA and protein is much more abundant. Here we examine chromatin structure and modification across the CFTR locus in primary human tracheal (HTE) and bronchial (NHBE) epithelial cells and airway cell lines including 16HBE14o- and Calu3. We identify regions of open chromatin that appear selective for primary airway epithelial cells and show that several of these are enriched for a histone modification (H3K4me1) that is characteristic of enhancers. Consistent with these observations, three of these sites encompass elements that have cooperative enhancer function in reporter gene assays in 16HBE14o- cells. Finally, we use chromosome conformation capture (3C) to examine the three-dimensional structure of nearly 800 kb of chromosome 7 encompassing CFTR and observe long-range interactions between the CFTR promoter and regions far outside the locus in cell types that express high levels of CFTR.

Gliomas are the most common central nervous system tumors. New technologies, including genetic research and advanced statistical methods, revolutionize the therapeutic approach to the patient and reveal new points of treatment options. Moreover, the 2021 World Health Organization Classification of Tumors of the Central Nervous System has fundamentally changed the classification of gliomas and incorporated many molecular biomarkers. Given the rapid progress in neuro-oncology, here we compile the latest research on prognostic and predictive biomarkers in gliomas. In adult patients, IDH mutations are positive prognostic markers and have the greatest prognostic significance. However, CDKN2A deletion, in IDH-mutant astrocytomas, is a marker of the highest malignancy grade. Moreover, the presence of TERT promoter mutations, EGFR alterations, or a combination of chromosome 7 gain and 10 loss upgrade IDH-wildtype astrocytoma to glioblastoma. In pediatric patients, H3F3A alterations are the most important markers which predict the worse outcome. MGMT promoter methylation has the greatest clinical significance in predicting responses to temozolomide (TMZ). Conversely, mismatch repair defects cause hypermutation phenotype predicting poor response to TMZ. Finally, we discussed liquid biopsies, which are promising diagnostic, prognostic, and predictive techniques, but further work is needed to implement these novel technologies in clinical practice.

A growing body of evidence indicates that miRNAs may be a class of genetic elements that can either drive or suppress oncogenesis. In this study we analyzed the somatic copy number variation of 14 miRNA genes frequently found to be either over- or underexpressed in lung cancer, as well as two miRNA biogenesis genes, DICER1 and DROSHA, in non-small-cell lung cancer (NSCLC). Our analysis showed that most analyzed miRNA genes undergo substantial copy number alteration in lung cancer. The most frequently amplified miRNA genes include the following: miR-30d, miR-21, miR-17 and miR-155. We also showed that both DICER1 and DROSHA are frequently amplified in NSCLC. The copy number variation of DICER1 and DROSHA correlates well with their expression and survival of NSCLC and other cancer patients. The increased expression of DROSHA and DICER1 decreases and increases the survival, respectively. In conclusion, our results show that copy number variation may be an important mechanism of upregulation/downregulation of miRNAs in cancer and suggest an oncogenic role for DROSHA.

Small nuclear U1-RNAs (snRNAs), the spliceosome components selectively recognizing donor splice sites (5ss), were engineered to restore correct mRNA processing in a cellular model of severe coagulation factor VII (FVII) deficiency, caused by the IVS7 9726 ؉ 5g/a change. Three U1-snRNAs, complementary to the mutated 5ss (U1 ؉ 5a) or to neighboring sequences were expressed with FVII minigenes in a hepatoma cell line. The U1-snRNAs reduced from 80% to 40% the exon 7 skipping, thus increasing exon definition. The U1 ؉ 5a construct also dramatically increased recognition of the correct 5ss over the 37-bp downstream cryptic site preferentially activated by the mutation, thus inducing appreciable synthesis of normal transcripts (from barely detectable to 50%). This effect, which was dose-dependent, clearly demonstrated that impaired recognition by the U1-snRNA was the mechanism responsible for FVII deficiency. These findings suggest compensatory U1-snRNAs as therapeutic tools in coagulation factor deficiencies caused by mutations at 5ss, a frequent cause of severe defects. IntroductionChanges affecting mRNA processing represent a frequent cause of severe coagulation factor defects 1-6 and of all inherited human diseases. 7-9 Different from gene therapy approaches inserting exogenous sequences that drive the expression of the missing factor, the specific correction of the mRNA processing would maintain the proper transcriptional control at the natural chromosomal environment and restore gene expression.Modified small nuclear RNAs (snRNAs) have been shown to promote changes in mRNA splicing in cellular and animal models of human diseases. However, these approaches were mainly aimed at inducing skipping of defective exons, 10,11 an approach that would not produce functional coagulation proteins, or masking newly generated cryptic exons, 12-14 an uncommon event in coagulation factor defects. Few attempts 15,16 have been made to redirect recognition of mutated donor splice site (5Јss) consensus sequences, the most frequent target in human disease genes. 8 On the other hand, bleeding disorders would significantly benefit even from low production of the correct mRNA and protein.As a model to exploit snRNAs for restoration of correct splicing in coagulation factor deficiencies, we chose the 9726 ϩ 5g/a mutation 17 in FVII occurring in the donor splice site of intron 7 (IVS7) at the ϩ 5 position, whose substitution has been frequently found to be associated with human diseases. [7][8][9] The homozygous patients experienced life-threatening hemorrhagic symptoms and require replacement therapy. Interestingly, coinheritance of the FVLeiden allele in a 9726 ϩ 5g/a homozygote produced a small increase in factor Xa and thrombin generation, resulting in a mild bleeding phenotype. 18 Through expression of minigenes and use of U1-snRNAs designed to selectively target the mutated site, we provided evidence for partial restoration of factor VII (FVII) mRNA processing impaired by the 9726 ϩ 5g/a change. Methods Construction of plasmidsThe...

Metastasis remains a leading cause of cancer mortality due to the lack of specific inhibitors against this complex process. To identify compounds selectively targeting the metastatic state, we used the perinuclear compartment (PNC), a complex nuclear structure associated with metastatic behaviors of cancer cells, as a phenotypic marker for a high-content screen of over 140,000 structurally diverse compounds. Metarrestin, obtained through optimization of a screening hit, disassembles PNCs in multiple cancer cell lines, inhibits invasion in vitro, blocks metastatic development in three mouse models of human cancer, and extends survival of mice in a metastatic pancreatic cancer xenograft model with no organ toxicity or discernable adverse effects. Metarrestin disrupts the nucleolar structure and inhibits RNA polymerase (Pol) I transcription, at least in part by interacting with the translation elongation factor eEF1A2. Altogether, metarrestin represents a potential therapeutic approach for the treatment of metastatic cancer.

Genomic variations deep in the intronic regions of pre-mRNA molecules are increasingly reported to affect splicing events. However, there is no general explanation why apparently similar variations may have either no effect on splicing or cause significant splicing alterations. In this work we have examined the structural architecture of pseudoexons previously described in ATM and CFTR patients. The ATM case derives from the deletion of a repressor element and is characterized by an aberrant 5′ss selection despite the presence of better alternatives. The CFTR pseudoexon instead derives from the creation of a new 5′ss that is used while a nearby pre-existing donor-like sequence is never selected. Our results indicate that RNA structure is a major splicing regulatory factor in both cases. Furthermore, manipulation of the original RNA structures can lead to pseudoexon inclusion following the exposure of unused 5′ss already present in their wild-type intronic sequences and prevented to be recognized because of their location in RNA stem structures. Our data show that intrinsic structural features of introns must be taken into account to understand the mechanism of pseudoexon activation in genetic diseases. Our observations may help to improve diagnostics prediction programmes and eventual therapeutic targeting.

Background/Aims: Mutations in the CFTR gene cause Cystic Fibrosis (CF) the most common life-threatening autosomal recessive disease affecting Caucasians. We identified a CFTR mutation (c.120del23) abolishing the normal translation initiation codon, which occurs in two Portuguese CF patients. This study aims at functionally characterizing the effect of this novel mutation. Methods: RNA and protein techniques were applied to both native tissues from CF patients and recombinant cells expressing CFTR constructs to determine whether c.120del23 allows CFTR protein production through usage of alternative internal codons, and to characterize the putative truncated CFTR form(s). Results: Our data show that two shorter forms of CFTR protein are produced when the initiation translation codon is deleted indicating usage of internal initiation codons. The N-truncated CFTR generated by this mutation has decreased stability, very low processing efficiency, and drastically reduced function. Analysis of mutants of four methionine codons downstream to M1 (M82, M150, M152, M156) revealed that each of the codons M150/M152/M156 (exon 4) can mediate CFTR alternative translation. Conclusions: The CFTR N-terminus has an important role in avoiding CFTR turnover and in rendering effective its plasma membrane traffic. These data correlate well with the severe clinical phenotype of CF patients bearing the c.120del23 mutation.