Charles R. Hong

Selective Depletion of Mutant p53 by Cancer Chemopreventive Isothiocyanates and Their Structure−Activity Relationships

Isothiocyanates (ITCs) derived from cruciferous vegetables induce apoptosis in cancer cells. We demonstrate that certain naturally occurring ITCs selectively deplete mutant p53 but not the wild-type and do so via a transcription-independent mechanism. Direct p53 binding followed by conformational changes appears to be a mechanism by which mutant p53 is depleted. Structure-activity relationship studies (SARs) using naturally occurring and synthetic ITCs show that depletion is influenced by the ITC side-chain moiety. Furthermore, we show that cells with p53 mutations are more sensitive to cytotoxicity induced by phenethyl isothiocyanate (PEITC) than those with the wild-type protein. 2,2-Diphenylethyl ITC, a synthetic ITC, is one of the most potent depletors of mutant p53 studies and induces apoptosis to the greatest extent in mutant p53 breast cancer cells. Collectively, this study shows that mutant p53 depletion may be an important novel target for cancer chemoprevention and therapy by natural and synthetic ITCs.

Sensitization of non-small cell lung cancer cells to cisplatin by naturally occurring isothiocyanates.

We show that naturally occurring isothiocyanates (ITCs) sensitize human non-small cell lung cancer cells to cisplatin. Moreover, the structure of the ITC side chain moiety is important for sensitization. In NCI-H596 cells, 20 microM benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC) enhance the efficacy of various concentrations of cisplatin, but sulforaphane (SFN) does not. Reducing the concentration of BITC and PEITC to 10 microM still allows for the sensitization of cells to cisplatin. Neither cellular platinum accumulation nor DNA platination account for this increased cytotoxicity. BITC and PEITC deplete beta-tubulin, but SFN does not; this correlates with and may be important for sensitization.

Firearm injuries in the pediatric population: a tale of one city

BACKGROUND Firearm-related injuries are a significant cause of morbidity and mortality in children. To determine current trends and assess avenues for future interventions, we examined the epidemiology and outcome of pediatric firearm injuries managed at our regions two major pediatric trauma centers. METHODS Following institutional review board approval, we conducted a 5-year retrospective review of all pediatric firearm victims, 16 years or younger, treated at either of the regions two Level 1 pediatric trauma centers, St. Louis Childrens Hospital and Cardinal Glennon Childrens Medical Center. RESULTS There were 398 children treated during a 5-year period (2008–2013) for firearm-related injuries. Of these children, 314 (78.9%) were black. Overall, there were 20 mortalities (5%). Although most (67.6%) patients were between 14 years and 16 years of age, younger victims had a greater morbidity and mortality. The majority of injuries were categorized as assault/intentional (65%) and occurred between 6:00 pm and midnight, outside the curfew hours enforced by the city. Despite a regional decrease in the overall incidence of firearm injuries during the study period, the rate of accidental victims per year remained stable. Most accidental shootings occurred in the home (74.2%) and were self-inflicted (37.9%) or caused by a person known to the victim (40.4%). CONCLUSION Despite a relative decrease in intentional firearm-related injuries, a constant rate of accidental shootings suggest an area for further intervention. LEVEL OF EVIDENCE Prognostic and epidemiologic study, level IV.

Severe neurodevelopmental disability and healthcare needs among survivors of medical and surgical necrotizing enterocolitis: A prospective cohort study

PURPOSEnThis study characterizes neurodevelopmental outcomes and healthcare needs of extremely low birth weight (ELBW) survivors of necrotizing enterocolitis (NEC) compared to ELBW infants without NEC.nnnMETHODSnData were collected prospectively on neonates born 22-27weeks gestation or 401-1000g at 47 Vermont Oxford Network member centers from 1999 to 2012. Detailed neurodevelopmental evaluations were conducted at 18-24months corrected age. Information regarding rehospitalizations, postdischarge surgeries, and feeding was also collected. Severe neurodevelopmental disability was defined as: bilateral blindness, hearing impairment requiring amplification, inability to walk 10 steps with support, cerebral palsy, and/or Bayley Mental or Psychomotor Developmental Index <70. Diagnosis of NEC required both clinical and radiographic findings.nnnRESULTSnThere were 9063 children without NEC, 417 with medical NEC, and 449 with surgical NEC evaluated. Significantly higher rates of morbidity were observed among infants with a history of NEC. Those with surgical NEC were more frequently affected across all outcome measures at 18-24months corrected age: 38% demonstrated severe neurodevelopmental disability, nearly half underwent postdischarge operations, and a quarter required tube feeding at home.nnnCONCLUSIONnAt 18-24months, extremely low birth weight survivors of necrotizing enterocolitis were at markedly increased risk (p<0.001) for severe neurodevelopmental disability, postdischarge surgery, and tube feeding.nnnLEVEL OF EVIDENCEnII (prospective cohort study with <80% follow-up rate).

Growth morbidity in extremely low birth weight survivors of necrotizing enterocolitis at discharge and two-year follow-up.

PURPOSEnThe purpose of this study was to examine postnatal growth outcomes and predictors of growth failure at 18-24months corrected age among extremely low birth weight (ELBW) survivors of necrotizing enterocolitis (NEC) compared to survivors without NEC.nnnMETHODSnData were collected prospectively on ELBW (22-27weeks gestation or 401-1000g birth weight) infants born 2000-2013 at 46 centers participating in the Vermont Oxford Network follow-up project. Severe growth failure was defined as <3rd percentile weight-for-age.nnnRESULTSnThere were 9171 evaluated infants without NEC, 416 with medical NEC, and 462 with surgical NEC. Rates of severe growth failure at discharge were higher among infants with medical NEC (56%) and surgical NEC (61%), compared to those without NEC (36%). At 18-24months follow-up, rates of severe growth failure decreased and were similar between without NEC (24%), medical NEC (24%), and surgical NEC (28%). On multivariable analysis, small for gestational age, chronic lung disease, severe intraventricular hemorrhage or cystic periventricular leukomalacia, severe growth failure at discharge, and postdischarge tube feeding predicted <3rd percentile weight-for-age at follow-up.nnnCONCLUSIONSnELBW survivors of NEC have higher rates of severe growth failure at discharge. While NEC is not associated with severe growth failure at follow-up, one quarter of ELBW infants have severe growth failure at 18-24months.nnnTYPE OF STUDYnPrognosis study.nnnLEVEL OF EVIDENCEnII.

Long-term outcomes of pediatric intestinal failure

Management of pediatric intestinal failure has evolved in recent decades, with improved survival since the advent of specialized multidisciplinary intestinal failure centers. Though sepsis and intestinal failure associated liver disease still contribute to mortality, we now have growing data on the long-term outcomes for this population. While intestinal adaptation and parenteral nutrition weaning is most rapid during the first year on parenteral support, achievement of enteral autonomy is possible even after many years as energy and protein requirements decline dramatically with age. Intestinal transplant is an option for patients experiencing complications of long-term parenteral nutrition who are expected to have permanent intestinal failure, but outcomes are hindered by immunosuppression-related complications. Much of the available data comes from single center retrospective reports, with variable inclusion criteria, intestinal failure definitions, and follow-up durations; this limits the ability to analyze outcomes and identify best practices. As most children now survive long-term, the focus of management has shifted to the avoidance and management of comorbidities, support of normal growth and development, and optimization of quality of life for these medically and surgically complex patients.

Nutrition Delivery and Growth Outcomes in Infants With Gastroschisis

BACKGROUNDnWe aimed to describe nutrient intake and growth in infants with gastroschisis and identify factors associated with impaired growth.nnnMETHODSnRetrospective study of neonates who underwent gastroschisis repair from 2010 to 2015. Nutrient intake and weight-for-age z scores (WAZ) were recorded.nnnRESULTSnData from 60 eligible infants with median (Q1, Q3) gestational age of 36 weeks (35, 37) and birth weight 2418 g (2098, 2665) were analyzed. Median WAZ decreased from -0.71 (-1.08, -0.17) at birth to -1.08 (-1.58, -0.63) at discharge (P < .001); 30% experienced a >1.0 decline in WAZ. Parenteral nutrition (PN) was initiated soon after birth, and 14 (23%) patients had severe intestinal failure. Fourteen patients (23%) experienced central line-associated bloodstream infection (CLABSI) at a rate of 5.0 per 1000 catheter days. Factors independently associated with lower discharge WAZ and greater WAZ decline were CLABSI (P = .02) and prematurity (P = .02). By day 7, energy and protein intake were 90-100 kcal/kg/day and 3 g/kg/day, respectively. Median age to achieve enteral autonomy was 36 days (22, 82). Atresias, CLABSI, prematurity, and staged closure were associated with delayed enteral autonomy (P < .01). Among 34 patients with 1-year follow-up, WAZ improved from -1.16 (-1.74, -0.65) at discharge to 0.19 (-0.80, 0.61) at 12 months (P < .001).nnnCONCLUSIONnInfants with gastroschisis are dependent on PN and have a significant decline in WAZ during their hospital stay, predicted by prematurity and CLABSI. Efforts to prevent CLABSI and optimize enteral autonomy must be prioritized in this cohort.

Nutrition Delivery During Pediatric Extracorporeal Membrane Oxygenation Therapy

BACKGROUNDnMacronutrient delivery during pediatric ECMO therapy can be challenging. We examined predictors of nutrient delivery in the first 2 weeks of extracorporeal membrane oxygenation (ECMO) therapy in the pediatric intensive care unit (ICU).nnnMETHODSnDetails of macronutrient delivery were recorded in children (newborn-18 years of age) who survived 24 hours after cannulation to ECMO over a 3-year period (2012-2015).nnnRESULTSnWe analyzed data from 54 consecutive eligible patients, 43% female, with median (interquartile range) ECMO duration of 8.5 (6-24) days, age 0.1 (0, 16) months, ICU length of stay 32 (21, 60) days, and 28-day mortality 13%. Median weight for age z score declined from -0.1 at admission to -1.2 at 30 days (P = 0.013). At least 80% goal energy and protein was delivered in 35 (65%) and 33 (61%) patients, respectively, by day 7; 10% of energy and 11% protein goal was delivered enterally. Parenteral nutrition (PN) was utilized in 47 (87%) patients, initiated by day 1 (1, 3). Enteral nutrition (EN) was successfully delivered in 49 (94%) patients (35% postpyloric), initiated by day 6 (2, 16). Younger age (P = 0.01) and venoarterial mode of ECMO (P = 0.0014) were associated with lower EN delivery. Use of umbilical artery catheters or vasoactive infusions did not impede EN delivery. Late PN delivery was associated with cumulative protein deficits (P = 0.019) and failure to achieve nutrient delivery goals by day 7.nnnCONCLUSIONSnOptimal nutrient delivery was achieved in most patients by day 7, predominantly via PN. Early EN is feasible in low volumes, but PN may be essential to prevent cumulative energy and protein deficits during the first week of ECMO.

High-throughput identification of putative receptors for cancer-binding peptides using biopanning and microarray analysis

Phage-display peptide biopanning has been successfully used to identify cancer-targeting peptides in multiple models. For cancer-binding peptides, identification of the peptide receptor is necessary to demonstrate the mechanism of action and to further optimize specificity and target binding. The process of receptor identification can be slow and some peptides may turn out to bind ubiquitous proteins not suitable for further drug development. In this report, we describe a high-throughput method for screening a large number of peptides in parallel to identify peptide receptors, which we have termed reverse biopanning. Peptides can then be selected for further development based on their receptor. To demonstrate this method, we screened a library of 39 peptides previously identified in our laboratory to bind specifically to cancers after irradiation. The reverse biopanning process identified 2 peptides, RKFLMTTRYSRV and KTAKKNVFFCSV, as candidate ligands for the protein tax interacting protein 1 (TIP-1), a protein previously identified in our laboratory to be expressed in tumors and upregulated after exposure to ionizing radiation. We used computational modeling as the initial method for rapid validation of peptide-TIP-1 binding. Pseudo-binding energies were calculated to be -360.645 kcal mol(-1), -487.239 kcal mol(-1), and -595.328 kcal mol(-1) for HVGGSSV, TTRYSRV, and NVFFCSV respectively, suggesting that the peptides would have at least similar, if not stronger, binding to TIP-1 compared to the known TIP-1 binding peptide HVGGSSV. We validated peptide binding in vitro using electrophoretic mobility shift assay, which showed strong binding of RKFLMTTRYSRV and the truncated form TTRYSRV. This method allows for the identification of many peptide receptors and subsequent selection of peptides for further drug development based on the peptide receptor.

Surgical considerations for neonates with necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a potentially devastating condition that preferentially affects premature and low birth weight infants, with approximately half requiring acute surgical intervention. Surgical consult should be considered early on, and deterioration despite maximal medical therapy or the finding of pneumoperitoneum are the strongest indications for emergent surgical intervention. There is no clear consensus on the optimal surgical approach between peritoneal drainage and laparotomy; the best course of action likely depends on the infants comorbidities, hemodynamic status, size, disease involvement, and available resources. Patients who develop surgical NEC are at a significant risk for morbidity and mortality, with long-term complications including short bowel syndrome, growth failure, and neurodevelopmental impairment. Further research into strategies that optimize outcomes following surgery for NEC in the neonatal intensive care unit and long-term are paramount.