Targeting DNA Repair in Ovarian Cancer Treatment Resistance.

Most patients with advanced high-grade serous ovarian cancer (HGSOC) develop recurrent disease within 3 years and succumb to the disease within 5 years. Standard treatment for HGSOC is cytoreductive surgery followed by a combination of platinum (carboplatin or cisplatin) and taxol (paclitaxel) chemotherapies. Although initial recurrences are usually platinum-sensitive, patients eventually develop resistance to platinum-based chemotherapy. Accordingly, one of the major problems in the treatment of HGSOC and disease recurrence is the development of chemotherapy resistance. One of the causes of chemoresistance may be redundancies in the repair pathways involved in the response to DNA damage caused by chemotherapy. These pathways may be acting in parallel, where if the repair pathway that is responsible for triggering cell death after platinum chemotherapy therapy is deficient, an alternative repair pathway compensates and drives cancer cells to repair the damage, leading to chemotherapy resistance. In addition, if the repair pathways are epigenetically inactivated by DNA methylation, cell death may not be triggered, resulting in accumulation of mutations and DNA damage. There are novel and existing therapies that can drive DNA repair pathways towards sensitivity to platinum chemotherapy or targeted therapy, thus enabling treatment-resistant ovarian cancer to overcome chemotherapy resistance.

Differential gene expression and cytokine production from neutrophils in asthma phenotypes.

Asthma is characterised into eosinophilic and non-eosinophilic phenotypes based on inflammatory cell patterns in airway secretions. Neutrophils are important in innate immunity, and are increased in the airways in non-eosinophilic asthma. The present study investigated the activity of neutrophils in asthma phenotypes. Participants with eosinophilic (n = 8) and non-eosinophilic asthma (n = 9) and healthy controls (n = 11) underwent sputum induction and blood collection. Neutrophils were isolated and cultured with or without lipopolysaccharide. Cytokines were measured by ELISA, and gene expression was analysed using a gene expression microarray and quantitative PCR. In non-eosinophilic asthma, blood neutrophils released significantly higher levels of interleukin-8 at rest. Cytokine gene expression and sputum neutrophil protein production did not differ between asthma subtypes. Microarrays demonstrated closely related expression profiles from participants with non-eosinophilic asthma that were significantly distinct from those in eosinophilic asthma. A total of 317 genes were significantly altered in resting neutrophils from participants with non-eosinophilic asthma versus eosinophilic asthma, including genes related to cell motility and regulation of apoptosis. Non-eosinophilic and eosinophilic asthma are associated with specific gene expression profiles, providing further evidence that these phenotypes of asthma involve different molecular mechanisms of disease pathogenesis at the systemic level. The mechanisms of non-eosinophilic asthma may involve enhancement of blood neutrophil chemotaxis and survival.

A 1q44 deletion, paternal UPD of chromosome 2 and a deletion due to a complex translocation detected in children with abnormal phenotypes using new SNP array technology.

Children with intellectual disability, dysmorphic features, malformations and/or growth abnormalities frequently display normal karyotypes. Recent studies have shown that genome-wide single nucleotide polymorphism (SNP) arrays can be effective in detecting abnormalities involving copy number variation (CNV), deletions, duplications and loss of heterozygosity (LOH) that routine cytogenetic tests fail to identify. Five patients with various degrees of intellectual disability and/or dysmorphic features and other malformations were whole-genome genotyped using the Human-1 Genotyping BeadChip--Exon-Centrix 100K SNP arrays (Illumina). All patients had undergone routine cytogenetic testing; four patients had normal karyotypes, while one patient had an apparently balanced complex translocation involving chromosomes 1q25, 1q32, 2q23, 7q22 and 16q24. We detected deletions on chromosome 1q44 and 13q31.1 in one patient, and LOH of the entire chromosome 2 in another patient, both with cytogenetically normal karyotypes. The patient with the complex translocation had a deletion on chromosome 7q22.2-22.3, which is in conjunction with one of the translocation breakpoints. Our findings provide further evidence of there being a critical region for the development of microcephaly and corpus callosum abnormalities in children with distal 1q deletions. We have also shown that apparently balanced complex translocations might not be balanced at the DNA level, and we report the fourth case of paternal uniparental disomy of chromosome 2. The results of this study suggest that it may be desirable to investigate idiopathic mental retardation using genome-wide SNP arrays, in conjunction with other cytogenetic and molecular techniques.