Crystal structure of Bak bound to the BH3 domain of Bnip5, a noncanonical BH3 domain-containing protein

The activation or inactivation of B-cell lymphoma-2 (Bcl-2) antagonist/killer (Bak) is critical for controlling mitochondrial outer membrane permeabilization-dependent apoptosis. Its pro-apoptotic activity is controlled by intermolecular interactions with the Bcl-2 homology 3 (BH3) domain, which is accommodated in the hydrophobic pocket of Bak. Bcl-2-interacting protein 5 (Bnip5) is a noncanonical BH3 domain-containing protein that interacts with Bak. Bnip5 is characterized by its controversial effects on the regulation of the pro-apoptotic activity of Bak. In the present study, we determined the crystal structure of Bak bound to Bnip5 BH3. The intermolecular association appeared to be typical at first glance, but we found that it is maintained by tight hydrophobic interactions together with hydrogen/ionic bonds, which accounts for their high binding affinity with a dissociation constant of 775 nM. Structural analysis of the complex showed that Bnip5 interacts with Bak in a manner similar to that of the Bak-activating pro-apoptotic factor peroxisomal testis-enriched protein 1, particularly in the destabilization of the intramolecular electrostatic network of Bak. Our structure is considered to reflect the initial point of drastic and consecutive conformational and stoichiometric changes in Bak induced by Bnip5 BH3, which helps in explaining the effects of Bnip5 in regulating Bak-mediated apoptosis.

Cellular toxicity profile of a new ophthalmic sponge

Introduction: Ophthalmic sponges are used for cleaning the eye surface and absorbing fluids during ophthalmic procedures. This study compared the biological safety and stability of a new ophthalmic sponge, Occucell® (OccuTech Inc, Seongnam, Korea), on the human conjunctival epithelial cells with those of preexisting products to evaluate its clinical application.Materials and Methods: The cytotoxicity of four products, Occucell, a new product, Ultracell®, Eyetec-1, and Eyetec-2, on conjunctival epithelial cells, was evaluated using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) analysis. Additionally, human conjunctival epithelial cells were stained with a Live & Dead marker and observed using a fluorescence microscope. To evaluate the effect of the ophthalmic sponges on the secretion of IL-1β and TNF-α, cultured conjunctival epithelial cells were treated with 0.5% DMSO eluates of the ophthalmic sponges, and IL-1β and TNF-α mRNA levels were estimated using real-time polymerase chain reaction assays.Results: Cells treated with Occucell showed comparable viability to those treated with other preexisting products. Conjunctival epithelial cells showed more than 90% viability when treated with the ophthalmic sponge extracts, as determined by the MTT assay. No significant differences in the number of live & dead cells were observed between the control and treatment groups. Cells treated with all four ophthalmic sponge eluates showed similar IL-1β and TNF-α mRNA levels.Discussion: Occucell, an eye sponge used during ophthalmic surgery in clinical practice, did not affect the viability of conjunctival epithelial cells, and more than 90% of the cells were viable after the treatment. Further, Occucell showed similar effects on IL-1β and TNF-α secretion as that of other ophthalmic sponges used in the clinic. This suggested that Occucell is a safe product comparable to the preexisting products.

Insights into the recognition mechanism in the UBR box of UBR4 for its specific substrates

The N-end rule pathway is a proteolytic system involving the destabilization of N-terminal amino acids, known as N-degrons, which are recognized by N-recognins. Dysregulation of the N-end rule pathway results in the accumulation of undesired proteins, causing various diseases. The E3 ligases of the UBR subfamily recognize and degrade N-degrons through the ubiquitin-proteasome system. Herein, we investigated UBR4, which has a distinct mechanism for recognizing type-2 N-degrons. Structural analysis revealed that the UBR box of UBR4 differs from other UBR boxes in the N-degron binding sites. It recognizes type-2 N-terminal amino acids containing an aromatic ring and type-1 N-terminal arginine through two phenylalanines on its hydrophobic surface. We also characterized the binding mechanism for the second ligand residue. This is the report on the structural basis underlying the recognition of type-2 N-degrons by the UBR box with implications for understanding the N-end rule pathway.

Use of continuous infusion of nicardipine to control persistent postpartum hypertension: A retrospective study

To evaluate the effect of continuous infusion of nicardipine on the management of uncontrolled blood pressure (BP) during postpartum period. This retrospective study included 209 women diagnosed in hospital with hypertensive disorders during pregnancy and had uncontrolled BP after delivery between January 2018 to December 2020 Uncontrolled BP was defined as persistent elevation of systolic BP ≥ 160 mm Hg or diastolic BP ≥ 110 mm Hg. Patients were divided into 2 groups: nicardipine (N = 53; continuous nicardipine infusion and additional bolus of labetalol or hydralazine) and control (N = 156; consecutive bolus of labetalol or hydralazine). BP data were analyzed using the Mann-Whitney U and χ2 tests by dividing the time interval of 4 hours by the delivery time. The highest BP trends showed that the mean values of both systolic and diastolic BP immediately before delivery were higher in the nicardipine group than in the control. After 8 to 12 hours following delivery, both systolic and diastolic BP were lower in the nicardipine group than in the control. Subsequently, 16 to 20 hours after delivery, both systolic and diastolic BP were significantly lower in the nicardipine group than in the control (137/80 vs 141/84 mm Hg). Initially, the proportions of uncontrolled BP in the nicardipine group were higher than those in the control; however, it then became lower at all time intervals 8 hours after delivery. The proportions of patients who received additional antihypertensive agents and the median cumulative dosages were lower in the nicardipine group than in the control. Continuous infusion of nicardipine can help manage uncontrolled BP during the postpartum period.

Two Cases of Adult Inclusion Conjunctivitis Masquerading as Chronic Conjunctivitis

Purpose: To report two cases of adult inclusion conjunctivitis masquerading as chronic conjunctivitis.Case summary: (Case 1) A 34-year-old man presented with a foreign body sensation in his right eye for 2 months. At the first visit, slit lamp examination showed follicles on the inferior palpebral conjunctiva. Chlamydia trachomatis immunoglobulin M (IgM) antibody and polymerase chain reaction (PCR) tests were positive. The patient was prescribed doxycycline for 1 week, which improved the symptoms, followed by gentamicin and levofloxacin for an additional 5 days, which further improved the clinical symptoms and conjunctivitis. (Case 2) A 39-year-old man presented with right eye pain and redness for 5 months. At the first visit, slit lamp examination showed follicles on the inferior palpebral conjunctiva. Chlamydia trachomatis IgM antibody and PCR tests were positive. After 1 week of doxycycline treatment, the clinical symptoms and conjunctivitis improved.Conclusions: Because adult inclusion conjunctivitis caused by chlamydial infection has non-specific symptoms, it can be misdiagnosed as chronic conjunctivitis. A detailed medical history and appropriate diagnostic tests are necessary to make this diagnosis.

Recapitulated Crosstalk between Cerebral Metastatic Lung Cancer Cells and Brain Perivascular Tumor Microenvironment in a Microfluidic Co-Culture Chip

Non-small cell lung carcinoma (NSCLC), which affects the brain, is fatal and resistant to anti-cancer therapies. Despite innate, distinct characteristics of the brain from other organs, the underlying delicate crosstalk between brain metastatic NSCLC (BM-NSCLC) cells and brain tumor microenvironment (bTME) associated with tumor evolution remains elusive. Here, a novel 3D microfluidic tri-culture platform is proposed for recapitulating positive feedback from BM-NSCLC and astrocytes and brain-specific endothelial cells, two major players in bTME. Advanced imaging and quantitative functional assessment of the 3D tri-culture model enable real-time live imaging of cell viability and separate analyses of genomic/molecular/secretome from each subset. Susceptibility of multiple patient-derived BM-NSCLCs to representative targeted agents is altered and secretion of serpin E1, interleukin-8, and secreted phosphoprotein 1, which are associated with tumor aggressiveness and poor clinical outcome, is increased in tri-culture. Notably, multiple signaling pathways involved in inflammatory responses, nuclear factor kappa-light-chain-enhancer of activated B cells, and cancer metastasis are activated in BM-NSCLC through interaction with two bTME cell types. This novel platform offers a tool to elucidate potential molecular targets and for effective anti-cancer therapy targeting the crosstalk between metastatic cancer cells and adjacent components of bTME.

High-throughput analysis of amniotic fluid proteins associated with histological chorioamnionitis in preterm premature rupture of membranes using an antibody-based microarray

PROBLEM

To identify potential proteins in the amniotic fluid (AF) that may be associated with histologic chorioamnionitis (HCA) in patients with preterm premature rupture of membranes (PPROM) using antibody-based microarray analysis.

METHOD OF STUDY

This was a retrospective cohort study involving 100 singleton pregnant women with PPROM at 24-34 weeks who underwent amniocentesis and delivered within 120 h of amniocentesis. First, the AF proteomes of 15 patients with PPROM and HCA were compared with those of 15 gestational age-matched patients without HCA using a protein microarray. Next, 12 candidate proteins associated with HCA were further validated in 100 consecutive patients with PPROM by ELISA.

RESULTS

Of 507 proteins assessed in the microarray analysis, 46 showed significant intergroup differences. Further quantification confirmed that the levels of EN-RAGE, IL-6, MMP-9, TNFR2, SPARC, TSP2, and uPA were higher in the AF of PPROM patients with HCA than in those without. Multivariate analyses also showed that elevated AF EN-RAGE, IL-6, MMP-9, and TNFR2 levels were independently associated with HCA when adjusted for baseline variables. The frequency of the highest quartile of the aforementioned proteins significantly increased as the total grade of HCA increased; the risk of HCA significantly increased with increasing AF levels of each protein (P for trend < .001).

CONCLUSIONS

Using protein-antibody microarray technology, we discovered several potential AF proteins (EN-RAGE, IL-6, MMP-9, and TNFR2) independently associated with HCA in patients with PPROM. Furthermore, we demonstrated a direct correlation between the gradation of the intra-amniotic inflammatory response and HCA severity.

The association between maternal pre-pregnancy body mass index and pregnancy outcomes of preeclampsia

OBJECTIVE

To evaluate the effects of pre-pregnancy maternal body mass index (BMI) to pregnancy outcomes in patients diagnosed as preeclampsia.

MATERIALS AND METHODS

This was a retrospectively study on women who had been diagnosed as preeclampsia and delivered at Seoul National University Bundang Hospital between June 2017 and March 2020. Multifetal gestation, major fetal anomaly, and fetal death in utero were excluded. A total of 150 singleton pregnancies were included and divided into four groups according to the pre-pregnancy BMI classification: underweight (<18.5 kg/m², n = 6), normal (18.5-22.9 kg/m², n = 66), overweight (23.0-24.9 kg/m², n = 26), and obese (≥25.0 kg/m², n = 52). Pregnancy outcomes including gestational age at delivery, birthweight, and delivery modes were reviewed.

RESULTS

The rates of preterm birth before 34 weeks of gestation were 67%, 49%, 35%, and 27% for underweight group, normal BMI group, overweight group, and obese group, respectively (p-trend = 0.006). The birthweight of newborn increased significantly as pre-pregnancy BMI increased (p-trend<0.001). The proportions of small for gestational age (SGA) were highest in underweight group and decreased as pre-pregnancy BMI increased (67%, 41%, 42%, and 10% for each group, respectively, p-trend<0.001).

CONCLUSION

The rates of preterm birth before 34 weeks and SGA increased as pre-pregnancy BMI decreased in patients with preeclampsia.

IMPLICATIONS FOR PRACTICE

Women with underweight before pregnancy are at the highest risk for preterm birth and SGA, therefore they need to be monitored more intensively when diagnosed as preeclampsia.

Brevundimonas Species Keratitis in a Patient without Underlying Disease

Purpose: To report a case of keratitis caused by Brevundimonas diminuta/vesicularis.Case summary: A 20-year-old man presented with decreased visual acuity and glare in his right eye from 2 days earlier. At the first visit, slit lamp examination revealed a 1.5 × 1.5 mm2-sized stromal infiltration, an edematous cornea and endothelial deposits in the center of the right eye. Microbiological examinations were performed from corneal scrapings. Treatment was started with topical eye drops (fortified cefazolin, fortified tobramycin) as empirical antibiotics. After several days, the cultures revealed Brevundimonas diminuta/vesicularis. After treatment with empirical antibiotic eye drops, the symptoms and visual acuity improved.Conclusions: We report a case of infectious keratitis caused by Brevundimonas diminuta/vesicularis, which has never previously been reported in the Republic of Korea.

Analysis of Early Neuroimaging Results in Patients with Acute Isolated Ocular Motor Nerve Palsy

Purpose: To evaluate the efficacy of early neuroimaging in patients with acute isolated 3rd, 4th, and 6th nerve palsy.Methods: Neuroimaging tests were performed in patients >50 years old with acute isolated 3rd, 4th, and 6th nerve palsy. The frequencies and types of abnormal findings were evaluated. All patients were divided into ischemic and non-ischemic groups and differences in clinical characteristics between groups were analyzed.Results: Of the 55 patients, nine (16.4%) had abnormal findings on brain imaging. Among 26 patients with 6th nerve palsy, four (15.4%) were found to have a cause including brain tumor, cerebrovascular compression, carotid cavernous fistula. Superior oblique muscle atrophy was found in two of 19 patients (10.5%) with 4th nerve palsy. Three of 10 patients (30%) with 3rd nerve palsy had abnormal findings and there were cases of pituitary apoplexy, posterior communicating, and cerebrovascular compression.Conclusions: In patients with acute isolated oculomotor paralysis, early neuroimaging tests play an important role in differential diagnosis and evaluation of causes that may lead to mortality.

Characteristics of Black Ginseng (Panax ginseng C.A. Mayer) Production Using Ginseng Stored at Low Temperature after Harvest

Ginseng processing often involves multiple drying and heat treatments. Ginseng is typically processed within one week of harvesting or is stored at low temperatures to prevent spoilage. Black ginseng (BG) is manufactured by repeating the heat treatment and drying process of ginseng several times. We compared the suitability of low-temperature stored ginseng (SG) and harvested ginseng (HG) as the components for black ginseng production. SG and HG were processed into black ginseng and the appearance change, free sugar content, and benzo[a]pyrene (BAP) content were observed. Appearance observations showed the SG to be suitable in terms of quality when heat-treated at a temperature of 95 ℃ or higher. The BAP content of the SG increased significantly as the steaming process was repeated. A maximum BAP concentration of 5.31 ± 1.12 μg/kg was measured in SG steamed from 2 to 5 times, making it unsuitable for processing into BG. SG and HG showed similar trends in the content of sucrose, fructose, and glucose during steaming. This study aimed to facilitate the proper choice of base material to improve the safety of black ginseng by limiting BAP production during processing.

Transcriptional regulatory networks of tumor-associated macrophages that drive malignancy in mesenchymal glioblastoma

BACKGROUND

Glioblastoma (GBM) is a complex disease with extensive molecular and transcriptional heterogeneity. GBM can be subcategorized into four distinct subtypes; tumors that shift towards the mesenchymal phenotype upon recurrence are generally associated with treatment resistance, unfavorable prognosis, and the infiltration of pro-tumorigenic macrophages.

RESULTS

We explore the transcriptional regulatory networks of mesenchymal-associated tumor-associated macrophages (MA-TAMs), which drive the malignant phenotypic state of GBM, and identify macrophage receptor with collagenous structure (MARCO) as the most highly differentially expressed gene. MARCO^high TAMs induce a phenotypic shift towards mesenchymal cellular state of glioma stem cells, promoting both invasive and proliferative activities, as well as therapeutic resistance to irradiation. MARCO^high TAMs also significantly accelerate tumor engraftment and growth in vivo. Moreover, both MA-TAM master regulators and their target genes are significantly correlated with poor clinical outcomes and are often associated with genomic aberrations in neurofibromin 1 (NF1) and phosphoinositide 3-kinases/mammalian target of rapamycin/Akt pathway (PI3K-mTOR-AKT)-related genes. We further demonstrate the origination of MA-TAMs from peripheral blood, as well as their potential association with tumor-induced polarization states and immunosuppressive environments.

CONCLUSIONS

Collectively, our study characterizes the global transcriptional profile of TAMs driving mesenchymal GBM pathogenesis, providing potential therapeutic targets for improving the effectiveness of GBM immunotherapy.

Single-cell RNA sequencing reveals the tumor microenvironment and facilitates strategic choices to circumvent treatment failure in a chemorefractory bladder cancer patient

BACKGROUND

Tumor cell-intrinsic mechanisms and complex interactions with the tumor microenvironment contribute to therapeutic failure via tumor evolution. It may be possible to overcome treatment resistance by developing a personalized approach against relapsing cancers based on a comprehensive analysis of cell type-specific transcriptomic changes over the clinical course of the disease using single-cell RNA sequencing (scRNA-seq).

METHODS

Here, we used scRNA-seq to depict the tumor landscape of a single case of chemo-resistant metastatic, muscle-invasive urothelial bladder cancer (MIUBC) addicted to an activating Harvey rat sarcoma viral oncogene homolog (HRAS) mutation. In order to analyze tumor evolution and microenvironmental changes upon treatment, we also applied scRNA-seq to the corresponding patient-derived xenograft (PDX) before and after treatment with tipifarnib, a HRAS-targeting agent under clinical evaluation.

RESULTS

In the parallel analysis of the human MIUBC and the PDX, diverse stromal and immune cell populations recapitulated the cellular composition in the human and mouse tumor microenvironment. Treatment with tipifarnib showed dramatic anticancer effects but was unable to achieve a complete response. Importantly, the comparative scRNA-seq analysis between pre- and post-tipifarnib-treated PDX revealed the nature of tipifarnib-refractory tumor cells and the tumor-supporting microenvironment. Based on the upregulation of programmed death-ligand 1 (PD-L1) in surviving tumor cells, and the accumulation of multiple immune-suppressive subsets from post-tipifarnib-treated PDX, a PD-L1 inhibitor, atezolizumab, was clinically applied; this resulted in a favorable response from the patient with acquired resistance to tipifarnib.

CONCLUSION

We presented a single case report demonstrating the power of scRNA-seq for visualizing the tumor microenvironment and identifying molecular and cellular therapeutic targets in a treatment-refractory cancer patient.

Anti-Inflammatory Activities of Isogosferol, a Furanocoumarin Isolated from Citrus junos Seed Shells through Bioactivity-Guided Fractionation

Citrus junos Tanaka is a traditional medicine for treating coughs, dyspepsia, diabetes, asthma, neuralgia, and inflammatory disorders, and is distributed in Asia, especially in Korea, Japan, and China. This study aimed to use bioactivity-guided fractionation to find therapeutic phytochemicals from C. junos seeds, which can attenuate inflammatory responses. Nine coumarins (1-9) were isolated from the methanolic extract of C. junos seed shells and the inhibitory effects against inflammatory mediators were investigated using murine macrophages. Among the coumarins, compound 3, isogosferol (ISO), more potently attenuated the production of nitric oxide (NO) in lipopolysaccharide (LPS)-induced RAW 264.7 cells. ISO also inhibited the expression of inducible nitric oxide (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated macrophages. Additionally, the phosphorylation of extracellular-regulated kinases (pERK)1/2 was reduced by ISO. We confirmed that ISO attenuated the release of interleukin-1 beta (IL-1β), which is a central mediator of the inflammatory response. These results demonstrate that ISO from C. junos seed shells may be a potent therapeutic candidate for the treatment of inflammatory diseases.

Impact of Balloon-Guiding Catheter Location on Recanalization in Patients with Acute Stroke Treated by Mechanical Thrombectomy

BACKGROUND AND PURPOSE

Mechanical thrombectomy with proximal flow control and forced aspiration may improve the outcome of endovascular revascularization therapy for patients with acute stroke. The purpose of this study was to compare the impact of balloon-guiding catheter locations in patients treated for anterior circulation acute ischemic stroke using mechanical thrombectomy.

MATERIALS AND METHODS

The influence of the balloon-guiding catheter location (proximal, balloon-guiding catheter tip proximal to C1 vertebral body; distal, between the skull base and the C1 vertebral body) was analyzed in patients with acute anterior circulation stroke treated with stent-retriever thrombectomy. The baseline angiographic/clinical characteristics, time intervals, recanalization rates, and clinical outcomes were compared.

RESULTS

The clinical analysis included 102 patients (mean age, 69.5 ± 12.8 years; male/female ratio = 52:50). The balloon-guiding catheter was located distally in 49 patients and proximally in 53 patients for flow control and forced aspiration during stent retrieval. The puncture-to-recanalization time was shorter in the distal group than in the proximal group (40 versus 56 minutes, P = .02). Successful and complete recanalizations were more frequently achieved in the distal group compared with the proximal group (98.0% versus 75.5%. P = .003; 67.3% versus 45.3%, P = .04, respectively). Multivariate analysis showed that the distal catheterization location was independently associated with successful recanalization (adjusted OR, 13.4; 95% CI, 2.4-254.8; P = .02).

CONCLUSIONS

Location of the balloon-guiding catheter has a significant impact on recanalization in patients with acute stroke. The balloon-guiding catheter should be positioned as distally as safely possible in the cervical ICA for maximally effective thrombectomy.

Glucose Controls the Expression of Polypyrimidine Tract-Binding Protein 1 via the Insulin Receptor Signaling Pathway in Pancreatic β Cells

In pancreatic β cells, glucose stimulates the biosynthesis of insulin at transcriptional and post-transcriptional levels. The RNA-binding protein, polypyrimidine tract-binding protein 1 (PTBP1), also named hnRNP I, acts as a critical mediator of insulin biosynthesis through binding to the pyrimidine-rich region in the 3'-untranslated region (UTR) of insulin mRNA. However, the underlying mechanism that regulates its expression in β cells is unclear. Here, we report that glucose induces the expression of PTBP1 via the insulin receptor (IR) signaling pathway in β cells. PTBP1 is present in β cells of both mouse and monkey, where its levels are increased by glucose and insulin, but not by insulin-like growth factor 1. PTBP1 levels in immortalized β cells established from wild-type (βIRWT) mice are higher than levels in β cells established from IR-null (βIRKO) mice, and ectopic re-expression of IR-WT in βIRKO cells restored PTBP1 levels. However, PTBP1 levels were not altered in βIRKO cells transfected with IR-3YA, in which the Tyr1158/1162/1163 residues are substituted with Ala. Consistently, treatment with glucose or insulin elevated PTBP1 levels in βIRWT cells, but not in βIRKO cells. In addition, silencing Akt significantly lowered PTBP1 levels. Thus, our results identify insulin as a pivotal mediator of glucose-induced PTBP1 expression in pancreatic β cells.

Reduced expression of the RNA-binding protein HuD in pancreatic neuroendocrine tumors correlates with low p27Kip1 levels and poor prognosis

For the majority of patients diagnosed with pancreatic neuroendocrine tumors (NETs), there is significant malignant potential with a poor prognosis; however, the molecular abnormalities and pathogenesis of pancreatic NETs have not been firmly established. Here, we report that loss of expression of the RNA-binding protein HuD correlates with low p27^Kip1 (p27) levels and poor prognosis in pancreatic NETs. HuD expression was frequently lost in many human pancreatic NETs, and these pancreatic NETs showed aggressive clinicopathological phenotypes with low p27 levels, increased tumor size, higher World Health Organization grade and pT stage of the tumor, and the presence of angioinvasion. Furthermore, loss of HuD was an independent, progression-free prognostic factor in multivariate survival analysis. However, the level of HuR, a member of the same Hu protein family as HuD, was not significantly correlated with pancreatic NET size and progression. Mechanistically, HuD enhanced p27 mRNA translation by interacting with both the 5'-untranslated region (UTR) and the 3'-UTR of p27 mRNA, and consequently suppressed cell cycle progression and tumor growth. In addition, HuD competed with miR-30a-3p for binding to the 3'-UTR of p27 mRNA, suggesting an interplay between HuD and miR-30a-3p in controlling p27 translation. Our results identify HuD as a pivotal suppressor of pancreatic NET growth, and suggest that HuD has potential value as a prognostic factor of pancreatic NETs. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Prospective analysis of factors associated with inadequate bowel preparation for colonoscopy in actual clinical practice

Background/Aims

Inadequate bowel preparation can result in prolonged procedure time and increased missed lesion and complication rates. This prospective study aimed to evaluate bowel preparation quality and identify the predictive factors for inadequate bowel preparation in actual clinical practice.

Methods

We included 399 patients who underwent colonoscopy between June 2015 and July 2016. Using the Aronchick bowel preparation scale, we defined a score ≤2 as adequate preparation and a score >2 as inadequate preparation.

Results

Mean patient age was 58.38±12.97 years; 60.6% were male. Indications for colonoscopy included screening (69.7%) and surveillance after polyp removal (21.3%). A split-dose regimen was prescribed to 55.4% of patients. The inadequate bowel preparation rate was 28.1%. Overall, the median time between the last bowel preparation agent dose and start of colonoscopy was 5.0 hours (range, 1.5-16.0 hours); that of the adequate group was 5.0 hours (range, 1.5-16.0 hours); and that of the inadequate group was 5 hours (range, 2-23 hours). The mean bowel preparation scale score of the ascending colon (1.94±0.25) was significantly higher than that of other colon segments. On multivariate analysis, elderly age, history of cerebrovascular disease, history of gastrectomy or appendectomy, and total preparation solution uptake <2 L were the independent predictors of inadequate bowel preparation.

Conclusions

The inadequate bowel preparation rate was 28.1%. Risk factors included elderly age and history of cerebrovascular disease or abdominal surgery. Patients with these risk factors require special care and education.

Establishment and antitumor effects of dasatinib and PKI-587 in BD-138T, a patient-derived muscle invasive bladder cancer preclinical platform with concomitant EGFR amplification and PTEN deletion

Muscle-invasive bladder cancer (MIBC) consists of a heterogeneous group of tumors with a high rate of metastasis and mortality. To facilitate the in-depth investigation and validation of tailored strategies for MIBC treatment, we have developed an integrated approach using advanced high-throughput drug screening and a clinically relevant patient-derived preclinical platform. We isolated patient-derived tumor cells (PDCs) from a rare MIBC case (BD-138T) that harbors concomitant epidermal growth factor receptor (EGFR) amplification and phosphatase and tensin homolog (PTEN) deletion. High-throughput in vitro drug screening demonstrated that dasatinib, a SRC inhibitor, and PKI-587, a dual PI3K/mTOR inhibitor, exhibited targeted anti-proliferative and pro-apoptotic effects against BD-138T PDCs. Using established patient-derived xenograft models that successfully retain the genomic and molecular characteristics of the parental tumor, we confirmed that these anti-tumor responses occurred through the inhibition of SRC and PI3K/AKT/mTOR signaling pathways. Taken together, these experimental results demonstrate that dasatinib and PKI-587 might serve as promising anticancer drug candidates for treating MIBC with combined EGFR gene amplification and PTEN deletion.

Preclinical and clinical implications of TERT promoter mutation in glioblastoma multiforme

The promoter region of the telomerase reverse transcriptase gene (TERT) is mutated in a subpopulation of patients with glioblastoma multiforme (GBM). In the present study, preclinical and clinical implications of the mutation were analyzed in 25 GBMs to evaluate its utility as a therapeutic target. Associations between the TERT promoter mutation and a number of preclinical/clinical characteristics were analyzed. Notably, the TERT promoter mutation was identified in 92.3% of GBMs where dissociated cells revealed in vitro sphere formation capacity; while the TERT promoter mutation was identified in 33.3% of GBMs without in vitro sphere formation capacity (P=0.004). In addition, this significantly increased mutation rate was observed in GBMs with in vivo tumorigenic potential (80% vs. 0%; P=0.004). Furthermore, patients with GBM exhibiting the TERT promoter mutation demonstrated significantly decreased overall survival rate compared with patients lacking this mutation (81.7 vs. 152.6 weeks; P=0.026). The results of the present study indicated that the TERT promoter mutation is associated with the self-renewal capacity of GBM cells and clinical aggressiveness of GBMs, which may be translated to a targeting therapy against TERT to inhibit the self-renewal of GBM cells.

Abstract 797: Glioblastoma animal model using CRISPR-Cas9 technology

Current in vivo model system poses limitation on fully recapitulating genomic characteristics of a tumor due to high complexity and poor understanding of the heterogeneous microenvironment conditions in cancer pathogenesis. In an effort to address such issues, strategic models are required. In present study, we propose that the most representative cancer models have consistent tumor microenvironments and genomic mutations. The Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system is a powerful genome editing tool for efficient and precise genome engineering. Here, we employed CRISPR-Cas9 system in vivo to generate Cre-dependent Cas9 knock-in mouse (B6;129-Gt(ROSA)26Sortm1(CAG-cas9*,-EGFP)Fezh/J, Jackson lab.). The Cre-dependent Cas9 mouse models harbor combinations of genomic alterations including well-established oncogenes such as EGFRviii, c-MET, PDGFRa, IDH1 R132H and KRAS, EGFR, ALK, BRAF in Brain and Lung cancer models, respectively. While, they also consist of tumor suppressor genes including PTEN, NF1, Ink4a/ARF, Rb, TP53 and TP53, PTEN, NKx-1, APC in both Brain and Lung models, respectively. Cre-dependent model allows us to study in-depth into the tumor initiation and progression, while able to follow up in the role of tumor microenvironment in cancer maintenance. A better understanding of cancer models for preclinical research including their uses, as well as their limitations, may aid future potential studies regarding the development and implementation of new immune targeted therapies and potential validation of novel therapeutic biomarkers.

Citation Format: Da Eun Jeong, Kee Hang Lee, Sung Soo Kim, Yoon Kyung Bae, Hyun Nam, Ji Yoon Hwang, Hee Jang Pyeon, Hye Jin Song, Kyeung Min Joo. Glioblastoma animal model using CRISPR-Cas9 technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 797. doi:10.1158/1538-7445.AM2017-797

Abstract 165: Single-cell transcriptome analysis guides tailored combinatorial therapeutics in refractory kidney cancer

Metastatic renal cell carcinoma (mRCC) evolves from primary RCC (pRCC) and harbors multiple subpopulations with distinct molecular and phenotypic features. Such underlying intratumoral heterogeneity (ITH) imposes difficulties in designing marker-based clinical trials because targeted mono-therapy eliminates a specific subpopulation of tumor cells while leaving others unharmed. Accordingly, a rational combination strategy that minimizes the survival of the drug-resistant subpopulation in a given heterogeneous tumor is essential for long-term therapeutic efficacy. Here, we examined the ITH of a paired mRCC and pRCC using single-cell mRNA sequencing (scRNA-seq) to identify specific tumor cell populations with drug target pathway activation. From the single cell expression profiles, we found the highly activated status of the EGFR and Src signaling pathways in the mRCC compared to the pRCC, with supporting in vitro high-throughput drug screening results. Distinct features of intratumoral expression variability across mRCC single cells that were masked in the bulk measurement prompted us to test the co-targeting strategy for the EGFR and Src pathways with increased likelihood for complete response. This combinatorial strategy showed significantly better treatment effects on mRCC-derived xenograft platforms in vitro and in vivo than monotherapies. Taken together, our findings show clinical implications of scRNA-seq in designing effective treatment regimens for overcoming treatment failure to conventional monotherapies, and also provide novel insights to the unmet clinical needs in effective personalized treatments.

Citation Format: Kyu-Tae Kim, Hye Won Lee, Hae-Ock Lee, Hye Jin Song, Da Eun Jeong, Sang Shin, Hyunho Kim, Yoojin Shin, Do-Hyun Nam, Byong Chang Jeong, David G. Kirsch, Kyeung Min Joo, Woong-Yang Park. Single-cell transcriptome analysis guides tailored combinatorial therapeutics in refractory kidney cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 165.

The clinical usefulness of a web-based messaging system between patients with Crohn disease and their physicians

To avoid missing events associated with clinical activity, the authors previously developed a novel, web-based, self-reporting Crohn disease (CD) symptom diary. However, although this diary provided a means of self-checking based on responses to set questions based on Harvey-Bradshaw index scores, it was limited in terms of describing other specific symptoms. Thus, the authors added a space to the questionnaire, which allows patients to send clinicians questions or a description of unpredictable events. The aim of the present study was to assess the clinical usefulness of this messaging system by analyzing patients' messages.The messaging system between patients and their doctors was included in a webpage created for recording patients' symptom diaries (www.cdsd.or.kr). Using this system, patients can send messages easily at any time and doctors can read and respond to these messages immediately using a smart phone or computer. In the present study, the authors retrospectively reviewed 686 messages sent by 152 patients from July 2012 to July 2014 and patient medical records.Mean patient age was 29.0 ± 11.6 years and the male-to-female ratio was 99:53. Most messages regarded symptoms (381 messages, 55.5%), which was followed by self-reports about general condition (195 messages, 28.4%) and questions about treatment (71 messages, 10.3%). With respect to symptoms, abdominal pain was most common (145 cases, 21.1%) followed by hematochezia (36 cases, 5.2%). Problems about medication were the most frequently associated with treatment (65, 91.5%). Patients above 40 years showed a greater tendency to focus on symptoms and treatment (P = 0.025). The doctor answer rate was 56.3% (n = 386), and based on these responses, an early visit was needed in 28 cases (7.3%).Using this web-based messaging system, patients were able to obtain proper advice from their physicians without visiting clinics or searching the Internet, and in addition, 7.3% of messages prompted an early visit. Although longer follow-up is required, this study shows that the devised messaging system provides a clinically relevant communication tool for patients and physicians.

Application of single-cell RNA sequencing in optimizing a combinatorial therapeutic strategy in metastatic renal cell carcinoma

BACKGROUND

Intratumoral heterogeneity hampers the success of marker-based anticancer treatment because the targeted therapy may eliminate a specific subpopulation of tumor cells while leaving others unharmed. Accordingly, a rational strategy minimizing survival of the drug-resistant subpopulation is essential to achieve long-term therapeutic efficacy.

RESULTS

Using single-cell RNA sequencing (RNA-seq), we examine the intratumoral heterogeneity of a pair of primary renal cell carcinoma and its lung metastasis. Activation of drug target pathways demonstrates considerable variability between the primary and metastatic sites, as well as among individual cancer cells within each site. Based on the prediction of multiple drug target pathway activation, we derive a combinatorial regimen co-targeting two mutually exclusive pathways for the metastatic cancer cells. This combinatorial strategy shows significant increase in the treatment efficacy over monotherapy in the experimental validation using patient-derived xenograft platforms in vitro and in vivo.

CONCLUSIONS

Our findings demonstrate the investigational application of single-cell RNA-seq in the design of an anticancer regimen. The approach may overcome intratumoral heterogeneity which hampers the success of precision medicine.

Patient-derived xenografts from non-small cell lung cancer brain metastases are valuable translational platforms for the development of personalized targeted therapy

PURPOSE

The increasing prevalence of distant metastases from non-small cell lung cancer (NSCLC) indicates an urgent need for novel therapeutic modalities. Brain metastasis is particularly common in NSCLC, with severe adverse effects on clinical prognosis. Although the molecular heterogeneity of NSCLC and availability of various targeted agents suggest personalized therapeutic approaches for such brain metastases, further development of appropriate preclinical models is needed to validate the strategies.

EXPERIMENTAL DESIGN

We established patient-derived xenografts (PDX) using NSCLC brain metastasis surgical samples and elucidated their possible preclinical and clinical implications for personalized treatment.

RESULTS

NSCLC brain metastases (n = 34) showed a significantly higher successful PDX establishment rate than primary specimens (n = 64; 74% vs. 23%). PDXs derived from NSCLC brain metastases recapitulated the pathologic, genetic, and functional properties of corresponding parental tumors. Furthermore, tumor spheres established in vitro from the xenografts under serum-free conditions maintained their in vivo brain metastatic potential. Differential phenotypic and molecular responses to 20 targeted agents could subsequently be screened in vitro using these NSCLC PDXs derived from brain metastases. Although PDX establishment from primary NSCLCs was significantly influenced by histologic subtype, clinical aggressiveness, and genetic alteration status, the brain metastases exhibited consistently adequate in vivo tumor take rate and in vitro tumor sphere formation capacity, regardless of clinical and molecular conditions.

CONCLUSIONS

Therefore, PDXs from NSCLC brain metastases may better represent the heterogeneous advanced NSCLC population and could be utilized as preclinical models to meet unmet clinical needs such as drug screening for personalized treatments.