A Network of Conserved Synthetic Lethal Interactions for Exploration of Precision Cancer Therapy.

An emerging therapeutic strategy for cancer is to induce selective lethality in a tumor by exploiting interactions between its driving mutations and specific drug targets. Here we use a multi-species approach to develop a resource of synthetic lethal interactions relevant to cancer therapy. First, we screen in yeast ∼169,000 potential interactions among orthologs of human tumor suppressor genes (TSG) and genes encoding drug targets across multiple genotoxic environments. Guided by the strongest signal, we evaluate thousands of TSG-drug combinations in HeLa cells, resulting in networks of conserved synthetic lethal interactions. Analysis of these networks reveals that interaction stability across environments and shared gene function increase the likelihood of observing an interaction in human cancer cells. Using these rules, we prioritize ∼10(5) human TSG-drug combinations for future follow-up. We validate interactions based on cell and/or patient survival, including topoisomerases with RAD17 and checkpoint kinases with BLM.

Advances in understanding of presbycusis.

The pathophysiology of age-related hearing loss (ARHL), or presbycusis, involves a complex interplay between environmental and genetic factors. The fundamental biomolecular mechanisms of ARHL have been well described, including the roles of membrane transport, reactive oxygen species, cochlear synaptopathy, vascular insults, hormones, and microRNA, to name a few. The genetic basis underlying these mechanisms remains under-investigated and poorly understood. The emergence of genome-wide association studies has allowed for the identification of specific groups of genes involved in ARHL. This review highlights recent advances in understanding of the pathogenesis of ARHL, the genetic basis underlying these processes and suggests future directions for research and potential therapeutic avenues.

Combinatorial CRISPR-Cas9 screens for de novo mapping of genetic interactions.

We developed a systematic approach to map human genetic networks by combinatorial CRISPR-Cas9 perturbations coupled to robust analysis of growth kinetics. We targeted all pairs of 73 cancer genes with dual guide RNAs in three cell lines, comprising 141,912 tests of interaction. Numerous therapeutically relevant interactions were identified, and these patterns replicated with combinatorial drugs at 75% precision. From these results, we anticipate that cellular context will be critical to synthetic-lethal therapies.

Multiquadrant surgery in the robotic era: a technical description and outcomes for da Vinci Xi robotic subtotal colectomy and total proctocolectomy.

BACKGROUND: Common colorectal procedures that require access to all quadrants of the abdomen are subtotal colectomy (STC) and total proctocolectomy (TPC). These are frequently performed with a surgical robot, but multiquadrant operations have unique challenges during robot-assisted surgery. METHODS: Patients who underwent robotic STC or TPC with the da Vinci Xi surgical robot at our institution from July 1, 2016 through June 30, 2019 were identified by diagnosis and procedure codes. A technical description is provided for the techniques utilized at our institution. Outcomes included operative times (OT), supply cost and length of stay. Associated morbidity and mortality was also analyzed. RESULTS: From a review of our institution's robotic surgery data, 37 cases were identified that utilized the described technique. Of these cases, 21 were robotic STC and 16 were TPC. Total mean OT was 276.86 min (SD ± 119.49). Mean OT was further analyzed by year, which demonstrated an overall decrease in OT from 350.91 min (SD ± 46.38) in 2016 to 221.43 min (SD ± 16.46) in 2018 (p = 0.008). A total of 21 cases were performed prior to 2018. Overall OT for STC was 222.81 min (SD ± 14.54) compared to overall TPC OT 347.81 min (SD ± 34.35). Median length of stay was 5 days [25th and 75th percentiles 4, 6, respectively]. There was no 30-day mortality and only one return to operating room for mesenteric bleeding. There was a low risk of mortality associated with this technique. CONCLUSIONS: The current study provides the largest cohort of patients assessed who have undergone multiquadrant robotic STC or TPC. The study provides a detailed description of the technique utilized at our institution. There was no associated 30-day mortality and a low risk of morbidity. The data suggest that the learning curve for improved operative time is between 15 and 20 cases.

Pediatric COVID-19 Vestibular Neuritis.

Introduction With the number of COVID cases in children increasing, the variation in presentation seen in pediatric patients compared with adults has become more apparent. The typical adult presentation of COVID-19 infection, generally associated with acute respiratory symptoms, seems to differ from that seen in children, many of whom are initially asymptomatic. Case Presentation In this case, a previously healthy female adolescent presented with insidious onset nausea and weight loss, but a broad gastrointestinal workup was unrevealing. The delayed development of vertiginous symptoms later led to the identification of prior, asymptomatic COVID-19 infection as the suspected etiology of her presenting gastrointestinal symptoms. Conclusion This case highlights the notion that COVID-19 infection in children may have a delayed manifestation in the absence of acute respiratory systems. Given this, COVID should be included in the differential diagnosis early on in an effort to limit the risks and costs associated with broad, unrevealing workups.

Successful treatment of highly recurrent facial baroparesis in a frequent high-altitude traveler: a case report.

BACKGROUND: Facial baroparesis is a palsy of the seventh cranial nerve resulting from increased pressure compressing the nerve along its course through the middle ear cavity. It is a rare condition, most commonly reported in barotraumatic environments, in particular scuba diving and high-altitude air travel. We report here an unusual case of highly frequent baroparesis, workup, and successful treatment. CASE PRESENTATION: A 57-year-old Caucasian male frequent commercial airline traveler presented with a 4-year history of recurrent episodes of right-sided facial paralysis and otalgia, increasing in both frequency and severity. Incidents occurred almost exclusively during rapid altitude changes in aircraft, mostly ascent, but also during rapid altitude change in an automobile. Self-treatment included nasal and oral decongestants, nasal corticosteroids, and warm packs. Temporal bone computed tomography (CT) scan revealed possible right-sided dehiscence of the tympanic bone segment; audiogram and magnetic resonance imaging of the internal auditory canals were unremarkable. After a diagnosis of facial nerve baroparesis was made, the patient underwent myringotomy with insertion of a pressure equalization tube (PET) into the right tympanic membrane. Despite re-exposure to altitude change multiple times weekly post-treatment, the patient reported being symptom-free for more than 6 months following intervention. CONCLUSIONS: Prompt PET insertion may represent the preferred treatment for individuals who suffer recurrent episodes of facial baroparesis. Education regarding this rare condition may prevent unnecessary testing and treatment of affected patients. Future studies should explore the pathophysiology and risk factors, compare therapeutic options, and provide follow-up data to optimize the management of affected patients.

Chemogenetic profiling identifies RAD17 as synthetically lethal with checkpoint kinase inhibition.

Chemical inhibitors of the checkpoint kinases have shown promise in the treatment of cancer, yet their clinical utility may be limited by a lack of molecular biomarkers to identify specific patients most likely to respond to therapy. To this end, we screened 112 known tumor suppressor genes for synthetic lethal interactions with inhibitors of the CHEK1 and CHEK2 checkpoint kinases. We identified eight interactions, including the Replication Factor C (RFC)-related protein RAD17. Clonogenic assays in RAD17 knockdown cell lines identified a substantial shift in sensitivity to checkpoint kinase inhibition (3.5-fold) as compared to RAD17 wild-type. Additional evidence for this interaction was found in a large-scale functional shRNA screen of over 100 genotyped cancer cell lines, in which CHEK1/2 mutant cell lines were unexpectedly sensitive to RAD17 knockdown. This interaction was widely conserved, as we found that RAD17 interacts strongly with checkpoint kinases in the budding yeast Saccharomyces cerevisiae. In the setting of RAD17 knockdown, CHEK1/2 inhibition was found to be synergistic with inhibition of WEE1, another pharmacologically relevant checkpoint kinase. Accumulation of the DNA damage marker γH2AX following chemical inhibition or transient knockdown of CHEK1, CHEK2 or WEE1 was magnified by knockdown of RAD17. Taken together, our data suggest that CHEK1 or WEE1 inhibitors are likely to have greater clinical efficacy in tumors with RAD17 loss-of-function.