Value of image enhancement of endoscopic ultrasound for diagnosis of gastrointestinal subepithelial lesions.

Objectives: Among subepithelial lesions (SELs), gastrointestinal stromal tumors (GISTs) should be identified and surgically treated at an early stage. However, it is difficult to diagnose SELs smaller than 20 mm. In recent years, endoscopic ultrasound (EUS) elastography (EUS-EG) and contrast-enhanced harmonic EUS (CH-EUS) have been reported to be useful for the diagnosis of SELs, although the diagnostic accuracy of a combination of EUS techniques with image enhancement is unknown. Methods: Patients with SELs who underwent EUS-guided tissue acquisition, EUS shear-wave elastography (EUS-SWE), EUS strain elastography (EUS-SE), and CH-EUS from January 2019 to June 2023 were enrolled. To assess the diagnostic accuracy for differentiating GISTs from other SELs, shear-wave velocity on EUS-SWE, the strain ratio on EUS-SE, and vascularity on CH-EUS were determined and their diagnostic accuracies were compared. Results: Forty-three patients were enrolled. When the cut-off value was set at 3.27 m/s, the sensitivity, specificity, and diagnostic accuracy of shear-wave velocity were 28.6%, 86.2%, and 34.9%, respectively. When the cut-off value was set at 3.79, the sensitivity, specificity, and diagnostic accuracy of the strain ratio were 93.1%, 64.3%, and 83.7%, respectively. The sensitivity, specificity, and diagnostic accuracy of CH-EUS were 79.3%, 92.3%, and 83.7%, respectively. When EUS-SE was combined with CH-EUS, the sensitivity and diagnostic accuracy were the highest among binary combinations of image enhancement modalities. Conclusions: EUS-SE and CH-EUS are useful for differentiating GISTs from other SELs. Furthermore, the use of both modalities may further improve the identification of GISTs.

Endoscopic Ultrasound and Intraductal Ultrasound in the Diagnosis of Biliary Tract Diseases: A Narrative Review.

Endoscopic ultrasound (EUS) and intraductal ultrasound (IDUS) play very important roles in the field of biliary tract disease. Because of their excellent spatial resolution, the detection of small lesions and T- or N-staging of tumors have become possible. Additionally, contrast-enhanced EUS and the new imaging technique of detective flow imaging are reported to be useful for differential diagnosis. Furthermore, EUS-guided tissue acquisition is used not only for pathological diagnosis but also to collect tissue samples for cancer genome profiling. This review provides an overview of diagnosis utilizing the features and techniques of EUS and IDUS.

Performance evaluation of endoscopic ultrasonography needles: Experimental study.

Background and study aims The relative procedural performance of needles for endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/B) is unclear. The present study therefore compared six types of 22-gauge FNA/B needles using a bench simulator. Methods Resistance forces during needle puncture and removal, needle tip damage before and after procedure, leakage after puncture of mucinous cyst models, the shape of the puncture surface at the puncture site, amounts of samples extracted, ranges of needle deflection angles, and needle deformation after multiple procedures were compared using six types of needles. Results Maximum resistance forces during puncture and removal were highest for ProCore needles and lowest for Expect needles. None of the needles had damage after puncturing. SharkCore needles showed the highest amount of leakage, whereas FNA needles showed no leakage. The puncture tracts of FNA needles remained in the form of a flap at the puncture site, whereas FNB needles broke off the target material creating a hole. The target material removed was supplemented within the puncture needle. TopGain needles produced significantly larger samples than ProCore, EZShot3 Plus, and Expect needles. FNB needles produced larger and more core samples than FNA needles. EZShot3 Plus needles had the highest range of needle deflection angle using an elevator device and the lowest needle deformation after 20 punctures at full endoscopic angle and a full elevator. Conclusions The performance of the six needles differed in various ways. Understanding the characteristics of each needle may allow for selection of the appropriate needle for each situation.

Endoscopic ultrasonography for microvascular imaging without contrast enhancement in the differential diagnosis of pancreatic lesions.

OBJECTIVES: Detective flow imaging endoscopic ultrasonography (DFI-EUS) is a recent imaging modality developed for detecting fine vessels without the need for ultrasound contrast agents. The aim of the present study was to evaluate the utility of DFI-EUS for solid pancreatic lesions and to compare the diagnostic ability for pancreatic cancer (PC) between DFI-EUS, directional power Doppler (eFLOW) EUS, and contrast-enhanced harmonic (CH)-EUS. METHODS: Patients with a pancreatic lesion who underwent DFI-EUS, eFLOW-EUS, and CH-EUS between March 2019 and November 2023 were retrospectively enrolled. Final diagnoses were confirmed by pathologic examination of EUS-guided tissue acquisition and/or resected specimens. Lesions were categorized into the three patterns of poor, mild, and rich vascularity on DFI-EUS and eFLOW-EUS, and hypo-, iso-, and hypervascular on CH-EUS. PC was defined as a poor pattern on DFI-EUS and eFLOW-EUS, and a hypovascular pattern on CH-EUS. RESULTS: The final diagnoses of 90 examined tumors were PC (n = 57), inflammatory mass (n = 6), autoimmune pancreatitis (n = 13), neuroendocrine tumor (n = 9), and others (n = 5). The sensitivity, specificity, and accuracy for diagnosis of PC were 93%, 82%, and 88%, respectively, on DFI-EUS, 97%, 42%, and 77% on eFLOW-EUS, and 95%, 89%, and 92% on CH-EUS. The accuracy of DFI-EUS was significantly superior to eFLOW-EUS (P = 0.005), but no significant difference was found between DFI-EUS and CH-EUS. CONCLUSION: DFI-EUS is more sensitive for depicting vasculature than eFLOW-EUS, and has higher diagnostic sensitivity for PC. Evaluation of vascularity on DFI-EUS is useful for the differential diagnosis of pancreatic lesions without the need for intravenous contrast agent.

Serum trypsin as an early predictor of post-endoscopic retrograde cholangiopancreatography pancreatitis.

BACKGROUND: Serum amylase (AMY) levels measured 2-6 h after ERCP are a predictor of post-ERCP pancreatitis (PEP). Trypsin is one of the pancreatic enzymes elevated in the development of PEP. The study assessed whether serum trypsin (TRY) can predict early-stage PEP. METHODS: This prospective study included patients who underwent ERCP from June 2022 to May 2023. TRY, AMY, serum pancreatic AMY (P-AMY), and serum lipase (LIP) levels were measured immediately after ERCP and 2 h later. The primary outcome was the diagnostic abilities of TRY levels measured immediately (0 h-TRY) and 2 h after (2 h-TRY) ERCP to predict PEP (compared with the other serum pancreatic enzymes). RESULTS: Of 130 patients analyzed, 18 developed PEP. The sensitivity and specificity of 0 h-TRY were 83.3% and 69.6%, respectively, and those of 2 h-TRY were 88.9% and 72.3%, respectively. The area under the curve (AUC) for 0 h-TRY was significantly higher than that for 0 h-AMY (p = .006) and 0 h-P-AMY (p = .012), whereas the AUCs for 0 h-TRY and 0 h-LIP did not differ significantly (p = .563). The AUC for 2 h-TRY for predicting PEP was significantly higher than that for 2 h-AMY (p = .025), whereas there was no significant differences between the AUCs for 2 h-TRY and 2 h-P-AMY(p = .146), or between those for 2 h-TRY and 2 h-LIP (p = .792). The median increase ratio (expressed as a ratio relative to baseline) in TRY was highest among all of serum pancreatic enzymes tested immediately after ERCP (5.35, 1.72, 1.94, and 4.44 for TRY, AMY, P-AMY, and LIP, respectively). CONCLUSION: Measuring TRY immediately after ERCP is useful for the early prediction of PEP.

Endoscopic ultrasound-guided hepaticogastrostomy vs. antegrade metal stent placement keeping an access route in patients with malignant biliary obstruction.

BACKGROUND: Few studies have compared endoscopic ultrasound (EUS)-guided hepaticogastrostomy (HGS) with EUS-guided antegrade metal stent placement (AGMS). The purpose of this study was to compare times to recurrent biliary obstruction (TRBO) in patients who underwent HGS using metal stents (MS) and those who underwent AGMS keeping access routes with plastic stents (AGMS-AR). METHODS: This study retrospectively evaluated consecutive patients who underwent HGS or AGMS between September 2016 and December 2022. TRBO, overall survival (OS), and adverse event (AE) rates were compared in the two groups. The risk factors for RBO were determined using a multivariable Cox proportional hazards model. RESULTS: This study included 32 patients in the HGS group and 30 in the AGMS-AR group. Technical success rate was significantly higher in the HGS than in the AGMS-AR group (100 vs. 80%; P = 0.009). The technical success rate without tract dilation was significantly higher in the AGMS-AR than in the HGS group (83 vs. 38%; P < 0.001). RBO rates were significantly higher in the HGS than in the AGMS-AR group (53 vs. 17%; P = 0.024), whereas AE rates did not differ significantly. TRBO differed significantly in the HGS and AGMS-AR groups (159 days vs. not reached, P = 0.011), whereas OS did not differ significantly. Multivariable analysis revealed that HGS was an independent risk factor for RBO (hazard ratio, 6.48, P = 0.014). CONCLUSION: TRBO was significantly longer in patients who underwent AGMS with PS than HGS. AGMS with PS may be effective after the failure of ERCP in patients with malignant biliary obstruction.

Epigenetic Inhibitors as Alzheimer's Disease Therapeutic Agents.

Alzheimer's disease (AD) is the leading cause of senile dementia, and the rapid increase in the frequency of AD cases has been attributed to population aging. However, current drugs have difficulty adequately suppressing symptoms and there is still a medical need for symptomatic agents. On the other hand, it has recently become clear that epigenetic dysfunctions are deeply involved in the development of cognitive impairments. Therefore, epigenetics-related proteins have attracted much attention as drug targets for AD. Early-developed epigenetic inhibitors were inappropriate for AD treatment because of their limited potential for oral administration, blood-brain barrier penetration, high target selectivity, and sufficient dose-limiting toxicity which are essential properties for small molecule drugs targeting chronic neurodegenerative diseases such as AD. In recent years, drug discovery studies have been actively performed to overcome such problems and several novel inhibitors targeting the epigenetics-related proteins are of interest as promising AD therapeutic agents. Here, we review the small molecule inhibitors of histone deacetylase (HDAC), lysine-specific demethylase 1 (LSD1) or bromodomains and extra-terminal domain (BET) protein, that enable memory function improvement in AD model mice.

Identification of Proteolysis Targeting Chimeras (PROTACs) for Lysine Demethylase 5 and Their Neurite Outgrowth-Promoting Activity.

Lysine demethylase 5 (KDM5) proteins are involved in various neurological disorders, including Alzheimer's disease, and KDM5 inhibition is expected to be a therapeutic strategy for these diseases. However, the pharmacological effects of conventional KDM5 inhibitors are insufficient, as they only target the catalytic functionality of KDM5. To identify compounds that exhibit more potent pharmacological activity, we focused on proteolysis targeting chimeras (PROTACs), which degrade target proteins and thus inhibit their entire functionality. We designed and synthesized novel KDM5 PROTAC candidates based on previously identified KDM5 inhibitors. The results of cellular assays revealed that two compounds, 20b and 23b, exhibited significant neurite outgrowth-promoting activity through the degradation of KDM5A in neuroblastoma neuro 2a cells. These results suggest that KDM5 PROTACs are promising drug candidates for the treatment of neurological disorders.

Identification of a novel histone H2A mono-ubiquitination-inhibiting cell-active small molecule.

Histone H2A mono-ubiquitination plays important roles in epigenetic gene expression and is also involved in tumorigenesis. Small molecules controlling H2A ubiquitination are of interest as potential chemical tools and anticancer drugs. To identify novel small molecule inhibitors of H2A ubiquitination, we synthesized and evaluated several compounds designed based on PRT4165 (1), which is a reported histone ubiquitin ligase RING1A inhibitor. We found that compound 11b strongly inhibited the viability and reduced histone H2A mono-ubiquitination in human osteosarcoma U2OS cells. Therefore, compound 11b is a promising lead compound for the development of H2A histone ubiquitination-inhibiting small molecules.

Safety of skipping the tract dilation step for EUS-guided biliary drainage in patients with unresectable malignant biliary obstruction (with video).

BACKGROUND: Thin delivery system stents can be inserted directly without the need for a tract dilation step and are expected to reduce bile leakage during endoscopic ultrasound-guided biliary drainage (EUS-BD). The present study retrospectively compared the safety and efficacy of EUS-BD using a thin metal stent (< 7.5 Fr) with those of EUS-BD using a conventional stent (≥ 7.5 Fr). METHODS: The present study enrolled 112 patients who underwent EUS-BD using metal stents for unresectable malignant biliary obstruction between April 2016 and July 2022. The primary endpoint was the rate of adverse events (AEs). The secondary endpoints were clinical success rate, procedure time, procedure success rate in the absence of the tract dilation step, recurrent biliary obstruction rate, time to biliary obstruction, and overall survival. Risk factors associated with early AEs were also evaluated. RESULTS: The rate of early AEs was significantly lower (12% vs. 35%, P = 0.013) and the procedure success without the tract dilation step was significantly higher (82% vs. 33%, P < 0.001) in the thin than in the conventional delivery system stent group. None of the other secondary endpoints differed significantly between the two groups. Multivariate analysis showed that employing the tract dilation step during EUS-BD was a significant independent risk factor for early AEs (skipping vs. employing; HR, 9.66; 95% CI, 1.13-83.0, P = 0.028). CONCLUSION: Employing the tract dilation step during EUS-BD was a significant risk factor for early AEs. Metal stents with a delivery diameter < 7.5 Fr can be inserted directly without the tract dilation step, resulting in lower early AE rates.

Design, synthesis, and biological evaluation of phenylcyclopropylamine-entinostat conjugates that selectively target cancer cells.

Small molecule-based selective cancer cell-targeting can be a desirable anticancer therapeutic strategy. Aiming to discover such small molecules, we previously developed phenylcyclopropylamine (PCPA)-drug conjugates (PDCs) that selectively release anticancer agents in cancer cells where lysine-specific demethylase 1 (LSD1) is overexpressed. In this work, we designed PCPA-entinostat conjugates for selective cancer cell targeting. PCPA-entinostat conjugate 12 with a 4-oxybenzyl group linker released entinostat in the presence of LSD1 in in vitro assays and selectively inhibited the growth of cancer cells in preference to normal cells, suggesting the potential of PCPA-entinostat conjugates as novel anticancer drug delivery small molecules.

Role of contrast-enhanced harmonic endoscopic ultrasonography (EUS) and EUS elastography in pancreatic lesions.

Pancreatic cancers have a poor prognosis, and their incident rates have risen. Endoscopic ultrasonography (EUS) is an efficient and reliable diagnostic modality for pancreatic lesions, providing high spatial resolution. However, while EUS helps to detect minor pancreatic lesions, nearly all solid pancreatic lesions are hypoechoic, which creates difficulty in making differential diagnoses of pancreatic lesions. When diagnosing pancreatic lesions, the performance of image-enhanced EUS techniques is essential, such as EUS elastography or contrast-enhanced harmonic EUS (CH-EUS). CH-EUS diagnosis is based on assessing the vascularity of lesions, whereas tissue elasticity is measured via EUS elastography. Elastography is either strain or shear-wave, depending on the different mechanical properties being evaluated. The usefulness of enhanced EUS techniques is demonstrated in this review for the differential diagnosis of pancreatic lesions, including solid and cystic lesions, and pancreatic cancer staging.

Protocol for a Multi-Center Confirmatory Trial to Evaluate the Differential Diagnostic Performance of Contrast-Enhanced Ultrasonography Using Perflubutane in Patients with a Pancreatic Mass: A Multicenter Prospective Study.

For pancreatic masses, an evaluation of their vascularity using contrast-enhanced ultrasonography can help improve their characterization. This study was designed to evaluate the utility and safety of contrast-enhanced transabdominal ultrasonography (CE-TUS) and endoscopic ultrasonography (CE-EUS) in the diagnosis of pancreatic masses including solid or cystic masses. This multi-center comparative open-label superiority study is designed to compare Plain (P)-TUS/EUS alone with P-TUS/P-EUS plus CE-TUS/CE-EUS. Three hundred and one patients with a total of 232 solid pancreatic masses and 69 cystic masses were prospectively enrolled. The primary endpoints are to compare the diagnostic accuracy between P-TUS/P-EUS alone and P-TUS/P-EUS plus CE-TUS/CE-EUS for both the TUS and EUS of solid pancreatic masses, and to compare the diagnostic accuracy between P-EUS alone and P-EUS plus CE-EUS in cystic pancreatic masses. The secondary endpoints are to compare the diagnostic sensitivity and specificity of P-TUS/P-EUS alone and P-TUS/P-EUS plus CE-TUS/CE-EUS for pancreatic solid/cystic masses, and the accuracy of P-TUS alone and P-TUS plus CE-TUS for pancreatic cystic masses. Other secondary endpoints included comparing the diagnostic sensitivity, specificity, and accuracy of CE-TUS, CE-EUS and CE-computed tomography (CT) for solid/cystic pancreatic masses. The safety, degree of effective enhancement, and diagnostic confidence obtained with CE-TUS/CE-EUS will also be assessed.

Impact of sarcopenia on recurrent biliary obstruction after EUS-guided biliary drainage in patients with malignant biliary obstruction.

BACKGROUND AND AIMS: Sarcopenia is an important prognostic factor for cancer patients. The aim of this study was to assess the ability of sarcopenia to predict recurrent biliary obstruction (RBO) in patients with unresectable cancer after EUS-guided biliary drainage (EUS-BD). METHODS: The study enrolled 113 patients who underwent EUS-BD using the self-expandable metal stent (SEMS) for unresectable malignant biliary obstruction (MBO) between April 2016 and December 2021 at Wakayama Medical University Hospital. The skeletal muscle index at the third lumbar spine level (L3) was calculated from computed tomography images. We analyzed the cumulative incidence of RBO at 180 days after stent insertion. Univariate and multivariate analyses were performed to identify variables significantly associated with RBO. RESULTS: Seventy-six patients were assigned to the sarcopenia group, and 37 were assigned to the non-sarcopenia group. The 180-day cumulative incidence of RBO was 11% in the non-sarcopenia group and 29% in the sarcopenia group (p = 0.034). The time to RBO was significantly shorter for the sarcopenia group (p = 0.028; Gray's test). Multivariate analyses identified sarcopenia as an independent prognostic factor for RBO (present vs absent; HR 4.61; 95% CI 1.76-12.10, p = 0.001). The rates of biliary sludge/food impaction were significantly higher in the sarcopenia group for the causes of RBO (p = 0.048). There were no significant differences between the sarcopenia and the non-sarcopenia groups with respect to related EUS-BD adverse events. CONCLUSION: Sarcopenia is an independent indicator of RBO in patients with MBO who receive EUS-BD with SEMS.

Structural optimization of a lysine demethylase 5 inhibitor for improvement of its cellular activity.

Lysine demethylase 5 (KDM5) subfamily proteins are important in epigenetic gene regulation. They are involved in the growth and drug resistance of cancer cells. Therefore, KDM5s are potential cancer therapeutic targets, and their inhibitors hold promise as anti-cancer drugs. Several KDM5 inhibitors, including KDM5-C49 (2a), have exhibited potent KDM5-inhibitory activities in in vitro enzyme assays. However, they do not show enough cellular activity despite being converted to their prodrugs. We hypothesized that their poor lipophilicity should prevent them from sufficiently penetrating the cell membrane, and introducing more lipophilic groups should improve cellular activities. In this study, we investigated 2a and KDM5-C70 (3a), a prodrug of 2a, and attempted to improve its cellular activity by replacing the N,N-dimethyl amino group of 3a with more lipophilic groups. N-Butyl, N-methyl amino compound 2e exhibited potent and selective KDM5-inhibitory activity equal to that of 2a. Furthermore, the cell membrane permeability of 3e, an ethyl ester prodrug of 2e, was six times higher than that of 3a in a parallel artificial membrane permeation assay. In addition, western blot analysis indicated that treating human lung cancer A549 cells with 3e increased histone methylation levels more strongly than that with 3a. Thus, we identified compound 3e as a more cell-active KDM5 inhibitor that has sufficient cell membrane permeability.

A Structure-Activity Relationship Study of SNAIL1 Peptides as Inhibitors of Lysine-Specific Demethylase 1.

Peptides have recently garnered attention as middle-molecular-weight drugs with the characteristics of small molecules and macromolecules. Lysine-specific demethylase 1 (LSD1) is a potential therapeutic target for lung cancer, neuroblastoma, and leukemia, and some peptide-based LSD1 inhibitors designed based on the N-terminus of SNAIL1, a member of the SNAIL/SCRATCH family of transcription factors, have been reported. The N-terminus of SNAIL1 peptide acts as a cap of the catalytic site of LSD1, inhibiting interactions with LSD1. However, the structure-activity relationship (SAR) of these inhibitors is not yet fully understood. Therefore, in the present study, we aimed to uncover the SAR and to identify novel SNAIL1 peptide-based LSD1 inhibitors. We synthesized peptide inhibitor candidates based on truncating the N-terminus of SNAIL1 or substituting its amino acid residues. In the truncation study, we found that SNAIL1 1-16 (2), which was composed of 16 residues, strongly inhibited LSD1. Furthermore, we investigated the SAR at residues-3 and -5 from the N-terminus and found that peptides 2j and 2k, in which leucine 5 of the parent peptide is substituted with unnatural amino acids, cyclohexylalanine and norleucine, respectively, strongly inhibited LSD1. This result suggests that the hydrophobic interaction between the inhibitor peptides and LSD1 affects the LSD1-inhibitory activity. We believe that this SAR information provides a basis for the development of more potent LSD1 inhibitors.

Identification of a Histone Deacetylase 8 Inhibitor through Drug Screenings Based on Machine Learning.

Histone deacetylase 8 (HDAC8) is a zinc-dependent HDAC that catalyzes the deacetylation of nonhistone proteins. It is involved in cancer development and HDAC8 inhibitors are promising candidates as anticancer agents. However, most reported HDAC8 inhibitors contain a hydroxamic acid moiety, which often causes mutagenicity. Therefore, we used machine learning for drug screening and attempted to identify non-hydroxamic acids as HDAC8 inhibitors. In this study, we established a prediction model based on the random forest (RF) algorithm for screening HDAC8 inhibitors because it exhibited the best predictive accuracy in the training dataset, including data generated by the synthetic minority over-sampling technique (SMOTE). Using the trained RF-SMOTE model, we screened the Osaka University library for compounds and selected 50 virtual hits. However, the 50 hits in the first screening did not show HDAC8-inhibitory activity. In the second screening, using the RF-SMOTE model, which was established by retraining the dataset including 50 inactive compounds, we identified non-hydroxamic acid 12 as an HDAC8 inhibitor with an IC50 of 842 nM. Interestingly, its IC50 values for HDAC1 and HDAC3-inhibitory activity were 38 and 12 µM, respectively, showing that compound 12 has high HDAC8 selectivity. Using machine learning, we expanded the chemical space for HDAC8 inhibitors and identified non-hydroxamic acid 12 as a novel HDAC8 selective inhibitor.

Intraductal Papillary Neoplasm of the Bile Duct Treated with Argon Plasma Coagulation via Endoscopic Ultrasound-guided Choledochoduodenostomy.

A 93-year-old man presented to our hospital with a fever, abdominal pain, and jaundice. Computed tomography revealed bilateral bile duct dilation, cystic lesions with bile duct communication, and intraluminal solid nodules arising from the bile duct wall. The patient was diagnosed with intraductal papillary neoplasm of the bile duct. Surgery was not performed, considering the patient's age. It was impossible to control cholangitis using conventional endoscopic therapy. We therefore created an access route to the bile duct using endoscopic ultrasound-guided choledochoduodenostomy and inserted a lumen-apposed metal stent. Thereafter, we performed argon plasma coagulation of the tumor in the bile duct, which successfully prevented cholangitis recurrence.

Utility of contrast-enhanced harmonic endoscopic ultrasonography for prediction of pathological response after neoadjuvant chemotherapy in patients with pancreatic cancer.

OBJECTIVES: Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) plays an important role in the diagnosis of pancreatic lesions. The aim of this study was to evaluate whether CH-EUS is useful for predicting the treatment efficacy of neoadjuvant chemotherapy (NAC) determined by pathological response. METHODS: Patients who underwent CH-EUS before chemotherapy and surgical resection were divided into two groups according to poor (group-P) or rich tumor vascularity (group-R) determined by enhancement pattern on early- and late-phase CH-EUS. The pathological response to chemotherapy was categorized according to Evans' classification. Pathological analysis showing tumor cell destruction (>50 %) defined a good response. RESULTS: Early-phase CH-EUS classified 44 patients into group-R and 50 into group-P, whereas late-phase CH-EUS classified 10 into group-R and 84 into group-P. Early-phase CH-EUS classification resulted in significantly higher numbers of patients with a good response in the rich group (n = 19) than in the poor group (n = 4; P = 0.0015). Multivariate analysis showed that assignment to the rich group was the strongest independent factor associated with chemosensitivity (P = 0.006, hazard ratio = 5.66, 95 % confidence interval: 1.17-19.27). In resectable patients, the enhancement pattern was the only independent factor associated with chemosensitivity (group-P vs. group-R, P = 0.003; HR [95 % CI], 14.59 [1.38-154.38]). Late-phase CH-EUS did not reveal a significant difference between group-P and group-R. CONCLUSIONS: Evaluation of vascular pattern on CH-EUS could be useful for predicting the efficacy of NAC in patients with pancreatic cancer. The enhancement pattern on CH-EUS could be a one of the useful features for determining NAC indications in resectable pancreatic cancer patients.

Discovery of Selective Histone Deacetylase 1 and 2 Inhibitors: Screening of a Focused Library Constructed by Click Chemistry, Kinetic Binding Analysis, and Biological Evaluation.

Histone deacetylase 1 and 2 (HDAC1/2) inhibitors are potentially useful as tools for probing the biological functions of the isoforms and as therapeutic agents for cancer and neurodegenerative disorders. To discover potent and selective inhibitors, we screened a focused library synthesized by using click chemistry and obtained KPZ560 as an HDAC1/2-selective inhibitor. Kinetic binding analysis revealed that KPZ560 inhibits HDAC2 through a two-step slow-binding mechanism. In cellular assays, KPZ560 induced a dose- and time-dependent increase of histone acetylation and showed potent breast cancer cell growth-inhibitory activity. In addition, gene expression analyses suggested that the two-step slow-binding inhibition by KPZ560 regulated the expression of genes associated with cell proliferation and DNA damage. KPZ560 also induced neurite outgrowth of Neuro-2a cells and an increase in the spine density of granule neuron dendrites of mice. The unique two-step slow-binding character of o-aminoanilides such as KPZ560 makes them interesting candidates as therapeutic agents.