Probes for INS

RESULTS Microscopic analysis revealed that the full-length _HTT_ mRNA (_FL-HTT_) was retained in RNA nuclear clusters together with the incompletely spliced _HTT1a_ transcript. These clusters were not observed in zQ175 HD mouse model where, instead, _FL-Htt_ and _Htt1a_ mRNAs were detected as mostly cytoplasmic molecules. Immunohistochemistry showed a progressive appearance of aggregated HTT in nuclei in the cortex, striatum, hippocampus and cerebellum. HTRF indicated that the level of exon 1 HTT was highest in the cerebellum. Soluble mutant exon 1 HTT decreased with age, with concomitant increase in aggregated HTT. In YAC128 MEFs, _HTT1a_ was detected and ASOs targeting _HTT_ were efficient in lowering _HTT_ levels in this model system.

Huntington disease is caused by a CAG repeat expansion in exon 1 of the huntingtin gene (HTT) that is translated into a polyglutamine stretch in the huntingtin protein (HTT). We previously showed that HTT mRNA carrying an expanded CAG repeat was incompletely spliced to generate HTT1a, an exon 1 only transcript, which was translated to produce the highly aggregation-prone and pathogenic exon 1 HTT protein. This occurred in all knock-in mouse models of Huntington's disease and could be detected in patient cell lines and post-mortem brains. To extend these findings to a model system expressing human HTT, we took advantage of YAC128 mice that are transgenic for a yeast artificial chromosome carrying human HTT with an expanded CAG repeat. We discovered that the HTT1a transcript could be detected throughout the brains of YAC128 mice. We implemented RNAscope to visualise HTT transcripts at the single molecule level and found that full-length HTT and HTT1a were retained together in large nuclear RNA clusters, as well as being present as single transcripts in the cytoplasm. Homogeneous time-resolved fluorescence analysis demonstrated that the HTT1a transcript had been translated to produce the exon 1 HTT protein. The levels of exon 1 HTT in YAC128 mice, correlated with HTT aggregation, supportive of the hypothesis that exon 1 HTT initiates the aggregation process. Huntingtin-lowering strategies are a major focus of therapeutic development for Huntington's disease. These approaches often target full-length HTT alone and would not be expected to reduce pathogenic exon 1 HTT levels. We have established YAC128 mouse embryonic fibroblast lines and shown that, together with our QuantiGene multiplex assay, these provide an effective screening tool for agents that target HTT transcripts. The effects of current targeting strategies on nuclear RNA clusters are unknown, structures that may have a pathogenic role, or alternatively could be protective by retaining HTT1a in the nucleus and preventing it from being translated. In light of recently halted antisense oligonucleotide trials, it is vital that agents targeting HTT1a are developed, and that the effects of HTT-lowering strategies on the subcellular levels of all HTT transcripts and their various HTT protein isoforms are understood.

Recursive partitioning analysis (RPA) from the Radiation Therapy Oncology Group (RTOG)-0129 has identified a low-risk group of patients with oropharynx cancer (OPC) who might benefit from therapeutic de-intensification. These risk groups have not yet been reproduced in an independent cohort treated heterogeneously. Therefore, the objective of this analysis was to validate the RPA risk groups and examine the prognostic impact of novel factors.Patients with OPC were enrolled in a prospective study at 3 academic medical centers from 2013 to 2018. Medical record abstraction was used to ascertain clinical variables including staging and survival according to the 7th edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual. Human papillomavirus-positive tumor status was determined by p16 immunohistochemistry and/or HPV RNA in situ hybridization. Kaplan-Meier and log-rank methods were used to compare survival. Cox proportional hazards were used to generate univariate and multivariable hazard ratios (HRs).Median follow-up time was 3.2 years. The low-, intermediate-, and high-risk groups had significant differences in 2-year overall survival (OS, 99.1%; 95% CI, 94.4%-99.9% vs OS, 93.0%; 95% CI, 74.7%-98.2% vs OS, 80.0%; 95% CI, 40.9%-94.6%; Poverall = .0001) and 2-year progression-free survival (PFS, 97.5%; 95% CI, 92.4%-99.2% vs PFS, 89.3%; 95% CI, 70.3%-96.4% vs PFS, 80.0%; 95% CI, 40.9%-94.6%; Poverall < .002). After adjustment for age, sex, and level of educational attainment, OS and PFS were significantly lower for the intermediate- (OS adjusted hazard ratio [aHR], 5.0; 95% CI, 1.0-23.0; PFS aHR, 3.4; 95% CI, 1.0-11.5), and high- (OS aHR, 7.3; 95% CI, 1.4-39; PFS aHR, 5.0; 95% CI, 1.2-21.6) risk groups compared with the low-risk group. Lower education was also independently significantly associated with worse OS (aHR, 8.9; 95% CI, 1.8-44.3) and PFS (aHR, 3.1; 95% CI, 1.0-9.6).In patients with OPC, the RTOG-0129 RPA model is associated with OS and PFS in a heterogeneously treated cohort.