UHRF1 Is a Novel Druggable Epigenetic Target in Malignant Pleural Mesothelioma

INTRODUCTION

Ubiquitin-like with plant homeodomain and ring finger domains 1 (UHRF1) encodes a master regulator of DNA methylation that has emerged as an epigenetic driver in human cancers. To date, no studies have evaluated UHRF1 expression in malignant pleural mesothelioma (MPM). This study was undertaken to explore the therapeutic potential of targeting UHRF1 in MPM.

METHODS

Microarray, real-time quantitative reverse transcription-polymerase chain reaction, immunoblot, and immunohistochemistry techniques were used to evaluate UHRF1 expression in normal mesothelial cells (NMCs) cultured with or without asbestos, MPM lines, normal pleura, and primary MPM specimens. The impact of UHRF1 expression on MPM patient survival was evaluated using two independent databases. RNA-sequencing, proliferation, invasion, and colony formation assays, and murine xenograft experiments were performed to evaluate gene expression and growth of MPM cells after biochemical or pharmacologic inhibition of UHRF1 expression.

RESULTS

UHRF1 expression was significantly higher in MPM lines and specimens relative to NMC and normal pleura. Asbestos induced UHRF1 expression in NMC. The overexpression of UHRF1 was associated with decreased overall survival in patients with MPM. UHRF1 knockdown reversed genomewide DNA hypomethylation, and inhibited proliferation, invasion, and clonogenicity of MPM cells, and growth of MPM xenografts. These effects were phenocopied by the repurposed chemotherapeutic agent, mithramycin. Biochemical or pharmacologic up-regulation of p53 significantly reduced UHRF1 expression in MPM cells. RNA-sequencing experiments exhibited the pleiotropic effects of UHRF1 down-regulation and identified novel, clinically relevant biomarkers of UHRF1 expression in MPM.

CONCLUSIONS

UHRF1 is an epigenetic driver in MPM. These findings support the efforts to target UHRF1 expression or activity for mesothelioma therapy.

Multidisciplinary management of locally advanced and widely metastatic paraganglioma in a patient with life-threatening compressive symptoms

BACKGROUND

Patients presenting with locally advanced, metastatic paraganglioma with life-threatening compressive symptoms of critical anatomic structure pose a significant management challenge.

METHODS

We present a case of a 15-year-old patient with enlarging right neck mass causing dysphagia and respiratory compromise from near complete obstruction of the oropharynx.

RESULTS

Evaluation of the patient's family history led to the identification of a mutation in the succinate dehydrogenase subunit B (SDSD) gene (G725A). Laboratory and imaging workup revealed an 8.8 × 6.6 × 4.1 cm metabolically and biochemically active right neck mass, a tumor in the left para-aortic region, and multiple bony lesions consistent with widely metastatic disease. Multidisciplinary management included preoperative clinical optimization, coil embolization, and palliative resection of the neck mass.

CONCLUSION

Although the currently available treatment options for patients with advanced metastatic paraganglioma render no survival benefit, a multidisciplinary management approach aimed at relief of tumor-related symptoms and catecholamine excess should be undertaken.

Prospects for reducing and refining the use of dogs in the regulatory toxicity testing of pharmaceuticals

A workshop was held to critically discuss the need for a nonrodent species and the role of the dog in regulatory toxicity testing of pharmaceuticals; to discuss opportunities to reduce and refine the use of dogs in preclinical toxicology; and to identify a number of specific recommendations which could be feasibly achieved to move the process forward. To facilitate a preliminary evaluation of the contribution of dog studies to the risk assessment process, anonymised, unpublished data were provided from fully evaluated, repeat-dose toxicity studies in the rat and dog. Results of the International Life Sciences Institute (ILSI) Human Toxicity Project were also presented and discussed. Analysis of the data demonstrated that the dog can provide additional toxicity information, which, in some cases, was shown to be predictive for humans. Discussions indicated that there is potential for achieving a reduction in dog use and several possible approaches were identified. To further the progress of this initiative, there is a need to collate the results of pharmacology, toxicology, and clinical studies to address some of the proposed approaches. One of the outcomes of the workshop will be the establishment of a steering group to co-ordinate data collation for further analysis.

Marine serpulidae (Annelida : Polychaeta) of eastern Queensland and New South Wales

Excluding the Spirorbidae, 41 species of marine serpulids were found, including two new genera and 14 new species. Of the remainder, one genus and eight species are recorded for the first time from Australia. Type specimens and representatives of other species collected have been deposited in the Australian Museum, Sydney.