A functional link between lariat debranching enzyme and the intron-binding complex is defective in non-photosensitive trichothiodystrophy

The pre-mRNA life cycle requires intron processing; yet, how intron-processing defects influence splicing and gene expression is unclear. Here, we find that TTDN1/MPLKIP, which is encoded by a gene implicated in non-photosensitive trichothiodystrophy (NP-TTD), functionally links intron lariat processing to spliceosomal function. The conserved TTDN1 C-terminal region directly binds lariat debranching enzyme DBR1, whereas its N-terminal intrinsically disordered region (IDR) binds the intron-binding complex (IBC). TTDN1 loss, or a mutated IDR, causes significant intron lariat accumulation, as well as splicing and gene expression defects, mirroring phenotypes observed in NP-TTD patient cells. A Ttdn1-deficient mouse model recapitulates intron-processing defects and certain neurodevelopmental phenotypes seen in NP-TTD. Fusing DBR1 to the TTDN1 IDR is sufficient to recruit DBR1 to the IBC and circumvents the functional requirement for TTDN1. Collectively, our findings link RNA lariat processing with splicing outcomes by revealing the molecular function of TTDN1.

Epigenetic regulation of hybrid epithelial-mesenchymal cell states in cancer

Epithelial-to-mesenchymal transition (EMT) is a process by which cells lose their epithelial characteristics and gain mesenchymal phenotypes. In cancer, EMT is thought to drive tumor invasion and metastasis. Recent efforts to understand EMT biology have uncovered that cells undergoing EMT attain a spectrum of intermediate "hybrid E/M" states, which exist along an epithelial-mesenchymal continuum. Here, we summarize recent studies characterizing the epigenetic drivers of hybrid E/M states. We focus on the histone-modification writers, erasers, and readers that assist or oppose the canonical hybrid E/M transcription factors that modulate hybrid E/M state transitions. We also examine the role of chromatin remodelers and DNA methylation in hybrid E/M states. Finally, we highlight the challenges of targeting hybrid E/M pharmacologically, and we propose future directions that might reveal the specific and targetable mechanisms by which hybrid E/M drives metastasis in patients.

Stepped Behavioral and Biological Screening for Oral Oncogenic HPV DNA in Middle-aged and Elderly Adults: A Feasibility Study

Novel preventive interventions are needed to address the rising incidence of human papillomavirus (HPV)-mediated oropharyngeal cancer (HPV+ OPC). This pilot study evaluated the feasibility of a stepped, behavioral and biological screening program for oral oncogenic HPV infection, an intermediate HPV+ OPC outcome.

This was a cross-sectional, feasibility study. Eligible 45-74 years old adults identified from three clinical research registries were administered a behavioral risk survey (step 1). Participant tobacco use and sexual behavior history were translated into a quantifiable risk of oral oncogenic HPV DNA, according to prior National Health and Nutrition Examination Survey analyses. Females with >2% risk and males with >7% risk were offered biological screening for oral oncogenic HPV DNA (step 2) via an oral rinse and gargle specimen.

A total of 292 individuals were contacted, but only 144 (49%) were reached. Among these, 56 individuals (19%) were uninterested and 18 (13%) were ineligible. Seventy individuals began the survey and 66 completed it (step 1), among whom 46 were classified as low-risk. Among the remaining 20 participants classified as high-risk for an oral oncogenic HPV infection, 5% were current smokers and the median participant had performed oral sex on 10 unique partners. During step 2 (biological screening), 45% (9/20) completed testing, all of whom tested negative for oral oncogenic HPV DNA.

In this pilot of a stepped, oral oncogenic HPV screening program, enrollment and study completion were suboptimal. These barriers to screening should be characterized and addressed before reevaluating the feasibility of this program.

PREVENTION RELEVANCE

Novel preventive interventions are needed to address the rising incidence of HPV+ OPC. In this feasibility study, we characterized barriers to a two-step, behavioral and biological screening program for oral oncogenic HPV infection, an intermediate outcome for HPV+ OPC.

Low-risk human papilloma virus positive oropharyngeal cancer with one positive lymph node: Equivalent outcomes in patients treated with surgery and radiation therapy versus surgery alone

BACKGROUND

For human papilloma virus positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC), management recommendations for patients with a single metastatic lymph node <6 cm in diameter remain nebulous, leading to treatment heterogeneity in this common subgroup of patients.

METHODS

We utilized the National Cancer Database to perform survival and multivariable analyses of patients with HPV+ OPSCC with one positive lymph node <6 cm and negative surgical margins.

RESULTS

We found that 5-year survival is comparable between patients who receive surgery and adjuvant radiation versus surgery alone. In multivariable analyses, we found no significant difference in the hazard ratio of overall survival after adjusting for various potential confounders.

CONCLUSIONS

These data suggest that patients with margin-negative HPV+ OPSCC with a single positive lymph node <6 cm have comparable survival with or without adjuvant radiation. Future studies exploring outcomes for this specific group in randomized-controlled trials will be critical for further evaluating these initial observations.