CUL4A Ubiquitin Ligase Is an Independent Predictor of Overall Survival in Pancreatic Adenocarcinoma.

BACKGROUND/AIM: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with dismal prognosis. Genomic instability due to defects in cell-cycle regulation/mitosis or deficient DNA-damage repair is a major driver of PDAC progression with clinical relevance. Deregulation of licensing of DNA replication leads to DNA damage and genomic instability, predisposing cells to malignant transformation. While overexpression of DNA replication-licensing factors has been reported in several human cancer types, their role in PDAC remains largely unknown. We aimed here to examine the expression and prognostic significance of the DNA replication-licensing factors chromatin licensing and DNA replication factor 1 (CDT1), cell-division cycle 6 (CDC6), minichromosome maintenance complex component 7 (MCM7) and also of the ubiquitin ligase regulator of CDT1, cullin 4A (CUL4A), in PDAC. MATERIALS AND METHODS: Expression levels of CUL4, CDT1, CDC6 and MCM7 were evaluated by immunohistochemistry in 76 formalin-fixed paraffin-embedded specimens of PDAC patients in relation to DNA-damage response marker H2AX, clinicopathological parameters and survival. We also conducted bioinformatics analysis of data from online available databases to corroborate our findings. RESULTS: CUL4A and DNA replication-licensing factors were overexpressed in patients with PDAC and expression of CDT1 positively correlated with H2AX. Expression of CUL4A and CDT1 positively correlated with lymph node metastasis. Importantly, elevated CUL4A expression was associated with reduced overall survival and was an independent indicator of poor prognosis on multivariate analysis. CONCLUSION: Our findings implicate CUL4A, CDT1, CDC6 and MCM7 in PDAC progression and identify CUL4A as an independent prognostic factor for this disease.

The Licensing Factor Cdt1 Links Cell Cycle Progression to the DNA Damage Response.

The maintenance of genome integrity is essential for cellular survival and propagation. It relies upon the accurate and timely replication of the genetic material, as well as the rapid sensing and repairing of damage to DNA. Uncontrolled DNA replication and unresolved DNA lesions contribute to genomic instability and can lead to cancer. Chromatin licensing and DNA replication factor 1 (Cdt1) is essential for loading the minichromosome maintenance 2-7 helicase complex onto chromatin exclusively during the G1 phase of the cell cycle, thus limiting DNA replication to once per cell cycle. Upon DNA damage, Cdt1 rapidly accumulates to sites of damage and is subsequently poly-ubiquitinated by the cullin 4-RING E3 ubiquitin ligase complex, in conjunction with the substrate recognition factor Cdt2 (CRL4Cdt2), and targeted for degradation. We here discuss the cellular functions of Cdt1 and how it may interlink cell cycle regulation and DNA damage response pathways, contributing to genome stability.

Microbiome Hijacking Towards an Integrative Pest Management Pipeline.

Pesticides are necessary to fight agricultural pests, yet they are often nonspecific, and their widespread use is a hazard to the environment and human health. The genomic era allows for new approaches to specifically target agricultural pests, based on analysis of their genome and their microbiome. We present such an approach, to combat Bactrocera oleae, a widespread pest whose impact is devastating on olive production. To date, there is no specific pesticide to control it. Herein, we propose a novel strategy to manage this pest via identifying novel pharmacological targets on the genome of its obligate endosymbiotic bacterium Candidatus Erwinia dacicola. Three genes were selected as pharmacological targets. The 3D models of the Helicase, Polymerase, and Protease-C gene products were designed and subsequently optimized by means of molecular dynamics simulations. Successively, a series of structure-based pharmacophore models were elucidated in an effort to pave the way for the efficient high-throughput virtual screening of libraries of low molecular weight compounds and thus the discovery of novel modulating agents. Our methodology provides the means to design, test, and identify highly specific pest control substances that minimize the impact of toxic chemicals on health, economy, and the environment.

A series of Notch3 mutations in CADASIL; insights from 3D molecular modelling and evolutionary analyses.

CADASIL disease belongs to the group of rare diseases. It is well established that the Notch3 protein is primarily responsible for the development of CADASIL syndrome. Herein, we attempt to shed light to the actual molecular mechanism underlying CADASIL via insights that we have from preliminary in silico and proteomics studies on the Notch3 protein. At the moment, we are aware of a series of Notch3 point mutations that promote CADASIL. In this direction, we investigate the nature, extent, physicochemical and structural significance of the mutant species in an effort to identify the underlying mechanism of Notch3 role and implications in cell signal transduction. Overall, our in silico study has revealed a rather complex molecular mechanism of Notch3 on the structural level; depending of the nature and position of each mutation, a consensus significant loss of beta-sheet structure is observed throughout all in silico modeled mutant/wild type biological systems.

Antiviral Stratagems Against HIV-1 Using RNA Interference (RNAi) Technology.

The versatility of human immunodeficiency virus (HIV)-1 and its evolutionary potential to elude antiretroviral agents by mutating may be its most invincible weapon. Viruses, including HIV, in order to adapt and survive in their environment evolve at extremely fast rates. Given that conventional approaches which have been applied against HIV have failed, novel and more promising approaches must be employed. Recent studies advocate RNA interference (RNAi) as a promising therapeutic tool against HIV. In this regard, targeting multiple HIV sites in the context of a combinatorial RNAi-based approach may efficiently stop viral propagation at an early stage. Moreover, large high-throughput RNAi screens are widely used in the fields of drug development and reverse genetics. Computer-based algorithms, bioinformatics, and biostatistical approaches have been employed in traditional medicinal chemistry discovery protocols for low molecular weight compounds. However, the diversity and complexity of RNAi screens cannot be efficiently addressed by these outdated approaches. Herein, a series of novel workflows for both wet- and dry-lab strategies are presented in an effort to provide an updated review of state-of-the-art RNAi technologies, which may enable adequate progress in the fight against the HIV-1 virus.