Development and validation of a cell cycle progression signature for decentralized testing of men with prostate cancer.

Aim: The 46-gene Prolaris® cell cycle progression test provides information on the risk of prostate cancer progression. Here we developed and validated a 16-gene kit-based version. Methods: RNA was extracted from prostate cancer biopsy tissue. Amplification efficiency, minimum tumor content, repeatability, reproducibility and equivalence with the 46-gene test were evaluated. Results: Amplification efficiencies for all genes were within the acceptable range (90-110%), and samples with ≥50% tumor content were appropriate for the 16-gene test. Results were repeatable (standard deviation: 0.085) and reproducible (standard deviation: 0.115). Instrument, operator and kit lot had minimal impact on results. Cell cycle progression scores from the 46- and 16-gene tests were highly correlated (r = 0.969; bias = 0.217). Conclusion: The 16-gene test performs consistently and similarly to the 46-gene test.

Prostate cancer does not always require aggressive treatment, and some men with low risk of disease progression may chose active surveillance. One way to measure the risk of disease progression is the Prolaris^® cell cycle progression test, which is performed at a commercial testing facility and measures the expression of 46 genes. However, certain European countries would prefer to run this test at a centralized testing facility. To this end we developed a streamlined kit measuring 16 genes to be used in these testing facilities, and showed that the cell cycle progression scores derived from the kit test are robust and equivalent to those obtained with the larger 46-gene test.

Phenotypical Characterization of the Nuclear Egress of Recombinant Cytomegaloviruses Reveals Defective Replication upon ORF-UL50 Deletion but Not pUL50 Phosphosite Mutation.

Nuclear egress is a common herpesviral process regulating nucleocytoplasmic capsid release. For human cytomegalovirus (HCMV), the nuclear egress complex (NEC) is determined by the pUL50-pUL53 core that regulates multicomponent assembly with NEC-associated proteins and capsids. Recently, NEC crystal structures were resolved for α-, ß- and γ-herpesviruses, revealing profound structural conservation, which was not mirrored, however, by primary sequence and binding properties. The NEC binding principle is based on hook-into-groove interaction through an N-terminal hook-like pUL53 protrusion that embraces an α-helical pUL50 binding groove. So far, pUL50 has been considered as the major kinase-interacting determinant and massive phosphorylation of pUL50-pUL53 was assigned to NEC formation and functionality. Here, we addressed the question of phenotypical changes of ORF-UL50-mutated HCMVs. Surprisingly, our analyses did not detect a predominant replication defect for most of these viral mutants, concerning parameters of replication kinetics (qPCR), viral protein production (Western blot/CoIP) and capsid egress (confocal imaging/EM). Specifically, only the ORF-UL50 deletion rescue virus showed a block of genome synthesis during late stages of infection, whereas all phosphosite mutants exhibited marginal differences compared to wild-type or revertants. These results (i) emphasize a rate-limiting function of pUL50 for nuclear egress, and (ii) demonstrate that mutations in all mapped pUL50 phosphosites may be largely compensated. A refined mechanistic concept points to a multifaceted nuclear egress regulation, for which the dependence on the expression and phosphorylation of pUL50 is discussed.

A quantitative nuclear egress assay to investigate the nucleocytoplasmic capsid release of human cytomegalovirus.

Nuclear egress is a rate-limiting step of herpesviral replication, restricting the nucleocytoplasmic transport of viral capsids. The process is regulated by two viral nuclear egress proteins (core NEC pUL50-pUL53), which recruit additional cellular and viral proteins. The multicomponent NEC mediates disassembly of the nuclear lamina barrier and the docking of nuclear capsids. The quantitation of nuclear egress has been accomplished by electron microscopic analysis, but is generally hampered by the low number of detectable cytoplasmic capsids. A newly established method for the quantitation of viral nuclear egress improves the characterization of viral mutants, host cell permissiveness and antiviral drug efficacy. In this study, various strains of human cytomegalovirus (HCMV) were used to measure the replication efficiencies in primary human fibroblasts, applying methods of cell fractionation, DNase digestion, sucrose cushions and quantitative PCR. Several stages of optimization led to a reliable quantitative assay that allowed the characterization of viral nuclear egress efficacy. Using this assay, recovery of the nuclear egress of a NEC-defective HCMV mutant was quantitatively assessed by applying an inducible NEC-expressing fibroblast culture for trans-complementation. This novel assay system can be further used to accurately quantitate and characterize the functionality of nuclear egress of HCMV or other herpesviruses.