Abstract B05: ASN007, an oral ERK1/2 inhibitor, shows strong antitumor activity across a panel of KRAS subtype mutant cancer models

The RAS/MAPK pathway is one of the most commonly dysregulated signaling pathways found in human cancers. KRAS, HRAS and NRAS genes, which play a critical role in transducing the signal from receptor tyrosine kinases to the downstream target proteins such as BRAF and MEK1/2, are frequently mutated in most solid tumors. The extracellular signal-regulated kinases, ERK1 and ERK2 (ERK1/2), which are downstream of MEK and RAF kinases, serve as a key node in this crucial signaling pathway in tumor cells. Targeting ERK1/2 offers a promising therapeutic strategy for a broad range of cancers, particularly the ones driven by RAS mutations, and in overcoming resistance to MEK/BRAF inhibitors. In this report, we present discovery and characterization of a novel orally bioavailable compound, ASN007, that showed potent inhibition of ERK1/2 kinases in a biochemical assay with IC50 = 2 nM for both targets. Interestingly, ASN007 displayed a much slower dissociation rate (longer target residence time) as compared to other ERK inhibitors. ASN007 showed potent antiproliferative activity that was selective for RAS/MAPK pathway dependent cancer cell lines, and did not affect the growth of cell lines harboring PI3K pathway or receptor tyrosine kinase mutations. Of note, ASN007 showed much more potent and broader activity against a panel of RAS mutant cell lines as compared to other ERK1/2 inhibitors. In a panel of 96 KRAS mutant cell lines, ASN007 showed strong activity across all KRAS subtype mutations, including G12C, G12D, G12V and G13D. In tumor xenograft models harboring KRAS and NRAS mutations, a daily oral dosing regimen of ASN007 provided strong tumor growth inhibition and was well tolerated. ASN007 also showed strong single-agent antitumor activity in colorectal PDX models with various KRAS subtype mutations including G12C, G12D, and G12S. A clinical phase 1 trial of ASN007 in patients with BRAF and KRAS, HRAS and NRAS mutant melanoma, colorectal, non-small lung and pancreatic cancers is currently ongoing (NCT03415126).

Citation Format: Sanjeeva P. Reddy, Scott K. Thompson, Helen Usansky, Roger A. Smith, Louis Denis, Sandeeep Gupta. ASN007, an oral ERK1/2 inhibitor, shows strong antitumor activity across a panel of KRAS subtype mutant cancer models [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B05.

Abstract 5783: Strong antitumor activity of ASN007, an oral ERK1/2 inhibitor, in PDX tumor models with MAP kinase pathway alterations including KRAS mutations

The RAS/RAF/MEK pathway is frequently dysregulated in a broad range of cancers through mutations in several targets such as KRAS, NRAS, HRAS, BRAF, NF1 and receptor tyrosine kinases. Although MEK and BRAF inhibitors improve the outcome for patients with BRAF mutant melanoma and lung cancers, the duration of response is limited due to reactivation of the pathway. The extracellular-signal-regulated kinases, ERK1 and ERK2 (ERK1/2), which are downstream of MEK and BRAF kinases, serve as a key node in this crucial signaling pathway. Targeting ERK1/2 offers a promising therapeutic strategy for a broad range of cancers, particularly the ones driven by RAS mutations, and in overcoming resistance to MEK/BRAF inhibitors. Here, we present discovery and characterization of a novel orally bioavailable compound, ASN007, that showed inhibition of ERK1/2 kinases in a biochemical assay with IC50 = 2 nM for both targets. Interestingly, ASN007 displayed a much slower dissociation rate (longer target residence time) as compared to other ERK inhibitors. ASN007 inhibited the phosphorylation of ERK1/2 substrates such as RSK1, FRA1 and Elk1 in various cell lines with low nM IC50 values. ASN007 showed potent anti-proliferative activity that was selective for MAPK-pathway dependent cancer cell lines. Indeed, ASN007 showed much more robust activity against RAS mutant cell lines as compared to other ERK1/2 inhibitors. In a daily oral dosing regimen, ASN007 demonstrated strong tumor growth inhibition in BRAF, KRAS and NRAS mutant xenograft models in mice and was well tolerated at efficacious doses. Of note, ASN007 showed strong efficacy using various intermittent dosing regimens. It also showed a strong anti-tumor activity in colorectal PDX models with various KRAS mutations. Furthermore, ASN007 showed regression of tumor growth in a melanoma PDX model that was resistant to both MEK and BRAF inhibitors. In addition to the single agent activity, greater efficacy was observed when ASN007 was combined with immunotherapeutic agents such as an anti-PD-1 antibody or an IDO-1 inhibitor. ASN007 does not exhibit significant inhibition of CYP enzymes or the hERG channel. A Phase 1 trial with ASN007 in patients with BRAF and K-, H- and N-RAS mutant melanoma, colorectal, non-small lung and pancreatic cancers is being planned.

Citation Format: Sanjeeva P. Reddy, Niranjan S. Rao, Roger A. Smith, Scott K. Thompson, Sarper Toker. Strong antitumor activity of ASN007, an oral ERK1/2 inhibitor, in PDX tumor models with MAP kinase pathway alterations including KRAS mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5783.

Abstract B150: ASN007, a novel oral ERK inhibitor, shows robust antitumor activity in RAS mutant cancer models

The extracellular-signal-regulated kinases, ERK1 and ERK2 (ERK1/2), are key players in the RAS/RAF/MEK signaling pathway. This pathway is frequently hyper-activated in a wide range of cancers through mutations in upstream targets such as BRAF, RAS, and receptor tyrosine kinases. Inhibition of ERK1/2 offers a promising therapeutic strategy for these cancers, particularly the ones driven by RAS mutations. In order to inhibit this critical node of the RAS/RAF/MEK pathway, we discovered and characterized ASN007, a novel compound that shows potent inhibition of ERK1/2 kinases in a biochemical assay with low single-digit nM IC50 values. ASN007 showed a slow dissociation rate (long target residence time) as compared to several other known ERK inhibitors. In mechanistic cell-based assays, ASN007 inhibited the phosphorylation of ERK1/2 substrates such as RSK1, FRA1, and Elk1 in various cell lines. ASN007 showed single-digit nanomolar antiproliferative activity that was selective for MAPK-pathway dependent cancer cell lines. Indeed, ASN007 showed much more potent activity against a broader panel of KRAS, NRAS, and HRAS mutant cell lines compared to other ERK1/2 inhibitors such as BVD-523 and GDC-0994. In a daily oral dosing regimen, ASN007 demonstrated strong inhibition of tumor growth in multiple BRAF and KRAS mutant xenograft models in mice and was well tolerated at efficacious doses. Of note, ASN007 also showed strong efficacy using various intermittent dosing regimens. ASN007 has a good pharmacokinetic profile in preclinical species and does not exhibit significant inhibition of CYP enzymes or hERG channel. IND-enabling studies are ongoing in preparation for a phase 1 clinical trial to evaluate oral ASN007 in patients with BRAF and K- , H- , and N-RAS mutant cancers

Citation Format: Sanjeeva P. Reddy, Dhanalakshmi Sivanandhan, Purushottam Dewang, Niranjan Rao, Roger A. Smith, Scott K. Thompson. ASN007, a novel oral ERK inhibitor, shows robust antitumor activity in RAS mutant cancer models [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B150.

Development of a risk prediction model for Barrett's esophagus in an Australian population

Esophageal adenocarcinoma has poor 5-year survival rates. Increased survival might be achieved with earlier treatment, but requires earlier identification of the precursor, Barrett's esophagus. Population screening is not cost effective, this may be improved by targeted screening directed at individuals more likely to have Barrett's esophagus. To develop a risk prediction tool for Barrett's esophagus, this study compared individuals with Barrett's esophagus against population controls. Participants completed a questionnaire comprising 35 questions addressing medical history, symptom history, lifestyle factors, anthropomorphic measures, and demographic details. Statistical analysis addressed differences between cases and controls, and entailed initial variable selection, checking of model assumptions, and establishing calibration and discrimination. The area under the curve (AUC) was used to assess overall accuracy. One hundred and twenty individuals with Barrett's esophagus and 235 population controls completed the questionnaire. Significant differences were identified for age, gender, reflux history, family reflux history, history of hypertension, alcoholic drinks per week, and body mass index. These were used to develop a risk prediction model. The AUC was 0.82 (95% CI 0.78-0.87). Good calibration between predicted and observed risk was noted (Hosmer-Lemeshow test P = 0.67). At the point minimizing false positives and false negatives, the model achieved a sensitivity of 84.96% and a specificity of 66%. A well-calibrated risk prediction model with good discrimination has been developed to identify patients with Barrett's esophagus. The model needs to be externally validated before consideration for clinical practice.

Risk factors for delayed gastric emptying following laparoscopic repair of very large hiatus hernias

Background

Delayed gastric emptying can complicate surgery for hiatus hernia. The aim of this study was to quantify its incidence following laparoscopic repair of very large hiatus hernias, identify key risk factors for its occurrence and determine its impact on clinical outcomes.

Methods

Data collected from a randomized trial of patients who underwent laparoscopic mesh versus sutured repair of very large hiatus hernias (more than 50 per cent of stomach in chest) were analysed retrospectively. Delayed gastric emptying was defined as endoscopic evidence of solid food in the stomach after fasting for 6 h at 6 months after surgery.

Results

Delayed gastric emptying occurred in 19 of 102 patients (18·6 per cent). In univariable analysis, type 2 paraoesophageal hernia (relative risk (RR) 3·15, 95 per cent c.i. 1·41 to 7·06), concurrent anterior and posterior hiatal repair (RR 2·66, 1·14 to 6·18), hernia sac excision (RR 4·85, 1·65 to 14·24), 270°/360° fundoplication (RR 3·64, 1·72 to 7·68), division of short gastric vessels (RR 6·82, 2·12 to 21·90) and revisional surgery (RR 3·69, 1·73 to 7·87) correlated with delayed gastric emptying. In multivariable analysis, division of short gastric vessels (RR 6·27, 1·85 to 21·26) and revisional surgery (RR 6·19, 1·32 to 28·96) were independently associated with delayed gastric emptying. Delayed gastric emptying correlated with adverse gastrointestinal symptomatology, including higher rates of bloating, nausea, vomiting and anorexia, as well as reduced patient satisfaction with the operation and recovery.

Conclusion

Delayed gastric emptying following large hiatus hernia repair is common and associated with adverse symptoms and reduced patient satisfaction. Division of short gastric vessels and revisional surgery were independently associated with its occurrence.

Venous thromboembolism in patients with esophageal or gastric cancer undergoing neoadjuvant chemotherapy

There is a well-established link between cancer and venous thromboembolism (VTE), and patients receiving chemotherapy for esophageal or gastric cancer appear at high risk of developing VTE. The incidence of VTE in the neoadjuvant setting in these patients is poorly understood, as is the role for thromboprophylaxis during neoadjuvant chemotherapy. A PubMed search was conducted using a combination of terms including; esophageal & gastric cancer, deep venous thrombosis (DVT), VTE, neoadjuvant, chemotherapy and chemoradiotherapy. One hundred and fifty-four articles were retrieved and a narrative review was conducted. For patients with esophageal and gastric cancer the incidence of VTE ranged from 4 to 19%. Gastric cancer (Odds Ratio [OR] 6.38, [95% CI: 1.96-20.80]) and Stage III/IV disease, (OR 5.16 [95% CI: 1.29-20.73]) were identified as risk factors for developing VTE. Neoadjuvant chemotherapy was identified as an independent risk factor for developing VTE. Symptomatic and asymptomatic VTE have a similar effect on mortality. Median overall survival for asymptomatic VTE was 13.9 months (95% CI: 5.0-∞) versus 12.8 months (95% CI: 4.7-30.3) if the VTE was symptomatic. Neoadjuvant chemotherapy is a significant risk factor for VTE in patients with esophageal and gastric cancer. Intervention to minimize the risk using pharmacological and mechanical thromboprophylaxis should be considered, and this should start in the neoadjuvant period.

Evaluation of outcome after cardiomyotomy for achalasia using the Chicago classification

Background

Achalasia can be subdivided into manometric subtypes according to the Chicago classification. These subtypes are proposed to predict outcome after treatment. This hypothesis was tested using a database of patients who underwent laparoscopic Heller's cardiomyotomy with anterior fundoplication.

Methods

All patients who underwent Heller's cardiomyotomy for achalasia between June 1993 and March 2015 were identified from an institutional database. Manometry tracings were retrieved and re-reported according the Chicago classification. Outcome was assessed by a postal questionnaire, and designated a success if the modified Eckardt score was 3 or less, and the patient had not undergone subsequent surgery or pneumatic dilatation. Difference in outcome after cardiomyotomy was analysed with a mixed-effects logistic regression model.

Results

Sixty, 111 and 24 patients had type I, II and II achalasia respectively. Patients with type III achalasia were more likely to be older than those with type I or II (mean age 63 versus 50 and 49 years respectively; P = 0·001). Some 176 of 195 patients returned questionnaires after surgery. Type III achalasia was less likely to have a successful outcome than type II (odds ratio (OR) 0·38, 95 per cent c.i. 0·15 to 0·94; P = 0·035). There was no significant difference in outcome between types I and II achalasia (II versus I: OR 0·87, 0·47 to 1·60; P 0·663). The success rate at 3-year follow-up was 69 per cent (22 of 32) for type I, 66 per cent (33 of 50) for type II and 31 per cent (4 of 13) for type III.

Conclusion

Type III achalasia is a predictor of poor outcome after cardiomyotomy. There was no difference in outcome between types I and II achalasia.

Abstract 187: ASN0007, a potent ERK1/2 inhibitor with strong antitumor activity in multiple RAS mutant models

The extracellular-signal-regulated kinases, ERK1 and ERK2 (ERK1/2), play a critical role in the RAS/RAF/MEK signaling pathway which is quite frequently activated by mutations in upstream targets such as BRAF, RAS and receptor tyrosine kinases. Most of the resistance mechanisms to BRAF and MEK inhibitors ultimately lead to increase in phosphorylation of ERK1/2 suggesting the importance of this node in the RAS/RAF/MEK pathway even in the resistance setting. Therefore, inhibition of ERK1/2 offers a promising strategy to address both innate and acquired resistance to BRAF and MEK inhibitors in various solid tumors. In order to inhibit this critical node of the RAS/RAF/MEK pathway, we discovered and characterized ASN007, a novel compound that shows potent inhibition of ERK1/2 kinases in a biochemical assay with low single-digit IC50 values. In mechanistic cell-based assays, ASN007 inhibited the phosphorylation of ERK1/2 substrates such as pRSK1, FRA1 and Elk1 in various cell lines. As expected, the compound did not have any effect on the phosphorylation of ERK1/2. ASN007 showed strong anti-proliferative activity in both BRAF and RAS mutant cell lines. Importantly, when compared to other ERK1/2 inhibitors such as BVD-523 and GDC-0994, ASN007 showed potent antiproliferative activity in a much broader panel of KRAS, NRAS and HRAS mutant cell lines representing various histological tumor types. The compound also caused cell cycle arrest at the G0-G1 phase and induced apoptosis in both BRAF and RAS mutant cell lines. In a daily oral dosing regimen, ASN007 demonstrated strong inhibition of tumor growth in multiple BRAF and KRAS mutant xenograft models in mice and was well tolerated at efficacious doses. ASN007 has a good pharmacokinetic profile in pre-clinical species and does not exhibit significant inhibition of CYP enzymes or hERG channel. Based on its profile in preclinical studies, ASN007 is expected to show strong efficacy in BRAF and RAS mutant cancers. ASN007 is currently in preclinical development.

Citation Format: Sanjeeva P. Reddy, Dhanalakshmi Sivanandhan, Raghava Reddy Kethiri, Sreekala Nair, Purushottam Dewang, Mohd Zainuddin, Krishnakumar Vaithilingam, Roger A. Smith, Sandeep Gupta, Scott K. Thompson. ASN0007, a potent ERK1/2 inhibitor with strong antitumor activity in multiple RAS mutant models. [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 187.

Estrogen Blockade Reduces Auditory Feedback in CBA Mice

OBJECTIVE: To examine the effects of estrogen suppression on age-related changes in distortion product otoacoustic emissions (DPOAEs) and contralateral suppression (CS) of DPOAEs in CBA mice.

STUDY DESIGN AND SETTING: Young CBA mice received a slow-release shoulder implantation of either tamoxifen or placebo. Serial DPOAEs and CS of DPOAEs were obtained at 3-week intervals over a period of 9 weeks.

RESULTS: Although DPOAEs were maintained over the study interval, CS of DPOAEs decreased significantly with age in the experimental group. No such declines were observed in either the control animals or the untreated male mice.

CONCLUSIONS: Estrogen suppression negatively affects the MOC efferent feedback system.

SIGNIFICANCE: Our results support the hypothesis that estrogen plays an important role in the maintenance of auditory integrity. Additionally, our findings raise intriguing questions about auditory effects of hormonal shifts in humans resulting from menopause, hormone supplements such as oral contraceptives, and hormone replacement therapy as well as antiestrogens.

Molecular physiognomies and applications of adipose-derived stem cells

Adipose-derived stromal/stem cells (ASC) are multipotent with abilities to differentiate into multiple lineages including connective tissue and neural cells. Despite unlimited opportunity and needs for human and veterinary regenerative medicine, applications of adipose-derived stromal/stem cells are at present very limited. Furthermore, the fundamental biological factors regulating stemness in ASC and their stable differentiation into other tissue cells are not fully understood. The objective of this review was to provide an update on the current knowledge of the nature and isolation, molecular and epigenetic determinants of the potency, and applications of adipose-derived stromal/stem cells, as well as challenges and future directions. The first quarter of the review focuses on the nature of ASC, namely their definition, origin, isolation and sorting methods and multilineage differentiation potential, often with a comparison to mesenchymal stem cells of bone marrow. Due to the indisputable role of epigenetic regulation on cell identities, epigenetic modifications (DNA methylation, chromatin remodeling and microRNAs) are described broadly in stem cells but with a focus on ASC. The final sections provide insights into the current and potential applications of ASC in human and veterinary regenerative medicine.

Abstract B100: ASN003, a unique B-RAF inhibitor with additional selective activity against PI3K and mTOR kinases, shows strong antitumor activity in multiple xenograft models

Various genes in RAS-RAF and PI3K pathways are frequently mutated in a wide variety of solid tumors. Concurrent double mutations are also observed quite often in a broad range of tumor types. Combined inhibition of both pathways has been shown to impart greater efficacy in multiple tumor models in animals. In order to simultaneously block these pathways, we have discovered and characterized several molecules showing dual inhibition of the RAS-RAF and PI3K pathways. ASN003 has been identified as a lead compound with potent and highly selective inhibitory activity against B-RAF, PI3K and mTOR kinases (low nM IC50). Within the PI3K family, ASN003 has high selectivity for inhibition of PI3Kα and PI3Kδ over PI3Kβ. In cell-based mechanistic studies, ASN003 did not increase phospho-ERK levels in the KRAS mutant cell line HCT116 and thus may not cause paradoxical activation of RAS/MAPK pathway in tumors. Consistent with its dual inhibition profile, ASN003 showed strong antiproliferative activity in cell lines with B-RAF and PI3K pathway mutations as well as vemurafenib (B-RAF inhibitor)-resistant cell lines. ASN003 suppressed the phosphorylation of downstream targets of B-RAF, PI3K and mTOR in pharmacodynamic studies in multiple tumor models, indicating appropriate target engagement. In in vivo efficacy studies, ASN003 showed regression in a B-RAFV600E mutant A375 xenograft model and also caused significant tumor growth inhibition in RKO and A2058 tumor models, which harbor mutations in PIK3CA or PTEN genes, respectively, in addition to the B-RAF V600E mutation. Dual targeting of the B-RAF and PI3K pathways with ASN003 has the potential to treat and/or prevent the acquired resistance to selective B-RAF inhibitors, and may also treat a broader patient population and provide greater efficacy and survival benefit than selective B-RAF inhibitors or selective PI3K pathway inhibitors alone. Due to the lack of paradoxical activation, treatment with ASN003 may not cause skin toxicities seen with pure B-RAF inhibitors. ASN003 is currently in preclinical development and is expected to enter Phase I/II clinical trials by early 2016.

Citation Format: Scott K. Thompson, Mahaboobi Jaleel, Vijay Kumar Nyavanandi, Murali Ramachandra, Hosahalli Subramanya, Aravind Basavaraju, Vaibhav Sihorkar, Roger A. Smith, Niranjan Rao, Sandeep Gupta, Sanjeeva P. Reddy. ASN003, a unique B-RAF inhibitor with additional selective activity against PI3K and mTOR kinases, shows strong antitumor activity in multiple xenograft models. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B100.

Novel handheld magnetometer probe based on magnetic tunnelling junction sensors for intraoperative sentinel lymph node identification

Using magnetic tunnelling junction sensors, a novel magnetometer probe for the identification of the sentinel lymph node using magnetic tracers was developed. Probe performance was characterised in vitro and validated in a preclinical swine model. Compared to conventional gamma probes, the magnetometer probe showed excellent spatial resolution of 4.0 mm, and the potential to detect as few as 5 μg of magnetic tracer. Due to the high sensitivity of the magnetometer, all first-tier nodes were identified in the preclinical experiments, and there were no instances of false positive or false negative detection. Furthermore, these preliminary data encourage the application of the magnetometer probe for use in more complex lymphatic environments, such as in gastrointestinal cancers, where the sentinel node is often in close proximity to other non-sentinel nodes, and high spatial resolution detection is required.

Abstract B274: Discovery and characterization of a highly selective inhibitor of B-RAF, PI3K, and mTOR kinases with antitumor activity in B-RAF and B-RAF/PI3K pathway double mutant xenograft models

The RAS-RAF-MAPK and PI3K pathways are two major signaling pathways involved in the initiation and progression of a broad range of tumors. These two pathways are frequently activated in the majority of solid tumors through mutations in various components of the pathways. Inhibition of one pathway often leads to the activation of the other pathway. Preclinical studies have shown that simultaneous inhibition of these two pathways leads to greater efficacy in a broader range of tumor types. For example, despite the presence of the B-RAFV600E mutation, colorectal cancer tumors do not respond to B-RAF selective inhibitors. In contrast, the combination of B-RAF or MEK inhibitors with PI3K pathway inhibitors shows significant tumor growth inhibition in colorectal cancer xenograft models in mice. Currently, there are several clinical trials ongoing using combinations of inhibitors targeting both pathways. We employed a rational drug design approach to discover and develop a single compound with dual inhibition of both RAS-RAF-MAPK and PI3K pathways. EN3352 was identified as a lead compound with potent inhibitory activity against B-RAF, PI3K and mTOR kinases, with low nanomolar IC50 values. Profiling of EN3352 in a panel of 292 kinases showed that it is highly selective for these three kinases. Within the PI3K family, EN3352 is selective for inhibition of PI3Kα versus PI3Kβ. EN3352 showed broader anti-proliferative activity in tumor cell lines compared to the B-Raf selective inhibitors, vemurafenib and dabrafenib. EN3352 has good oral bioavailability in preclinical species and showed inhibition of phosphorylation of the downstream targets of B-RAF, PI3K and mTOR in various tumor models in mice. EN3352 showed regression in a B-RAFV600E mutant A375 xenograft model and also showed significant tumor growth inhibition in a RKO model, which harbors mutations in both B-RAF and PIK3CA genes. Dual targeting of the B-RAF and PI3K pathways with EN3352 has the potential to treat and/or prevent the acquired resistance to selective B-RAF inhibitors, and may also treat a broader patient population and provide greater efficacy and survival benefit than selective B-RAF inhibitors or selective PI3K pathway inhibitors alone.

(Disclosure: Funding for this research was provided by Endo Pharmaceuticals Inc.)

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B274.

Citation Format: Sanjeeva P. Reddy, Mahaboobi Jaleel, Vijay K. Nyavanandi, Murali Ramachandra, Hosahalli Subramanya, Aravind Basavaraju, Vaibhav Sihorkar, Roger A. Smith, Sandeep Gupta, Scott K. Thompson. Discovery and characterization of a highly selective inhibitor of B-RAF, PI3K, and mTOR kinases with antitumor activity in B-RAF and B-RAF/PI3K pathway double mutant xenograft models. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B274.

Twenty years of experience with laparoscopic antireflux surgery

BACKGROUND

There are few reports of large patient cohorts with long-term follow-up after laparoscopic antireflux surgery. This study was undertaken to evaluate changes in surgical practice and outcomes for laparoscopic antireflux surgery over a 20-year period.

METHODS

A standardized questionnaire, prospectively applied annually, was used to determine outcome for all patients undergoing laparoscopic fundoplication in two centres since commencing this procedure in 1991. Visual analogue scales ranging from 0 to 10 were used to assess symptoms of heartburn, dysphagia and satisfaction with overall outcome. Data were analysed to determine outcome across 20 years.

RESULTS

From 1991 to 2010, 2261 consecutive patients underwent laparoscopic fundoplication at the authors' institutions. Follow-up ranged from 1 to 19 (mean 7.6) years. Conversion to open surgery occurred in 73 operations (3.2 per cent). Revisional surgery was performed in 216 patients (9.6 per cent), within 12 months of the original operation in 116. There was a shift from Nissen to partial fundoplication across 20 years, and a recent decline in operations for reflux, offset by an increase in surgery for large hiatus hernia. Dysphagia and satisfaction scores were stable, and heartburn scores rose slightly across 15 years of follow-up. Heartburn scores were slightly higher and reoperation for reflux was more common after anterior partial fundoplication (P = 0.005), whereas dysphagia scores were lower and reoperation for dysphagia was less common (P < 0.001). At 10 years, satisfaction with outcome was similar for all fundoplication types.

CONCLUSION

Laparoscopic Nissen and partial fundoplications proved to be durable and achieved good long-term outcomes. At earlier follow-up, dysphagia was less common but reflux more common after anterior partial fundoplication, although differences had largely disappeared by 10 years.

Post-fundoplication contrast studies: is there room for improvement?

OBJECTIVE

Since the mid-1990s, laparoscopic fundoplication for gastro-oesophageal reflux disease has become the surgical procedure of choice. Several surgical groups perform routine post-operative contrast studies to exclude any (asymptomatic) anatomical abnormality and to expedite discharge from hospital. The purpose of this study was to determine the accuracy and interobserver reliability for surgeons and radiologists in contrast study interpretation.

METHODS

11 surgeons and 13 radiologists (all blinded to outcome) retrospectively reviewed the contrast studies of 20 patients who had undergone a laparoscopic fundoplication. Each observer reported on fundal wrap position, leak or extravasation of contrast and contrast hold-up at the gastro-oesophageal junction (on a scale of 0-4). A κ coefficient was used to evaluate interobserver reliability.

RESULTS

Surgeons were more accurate than radiologists in identifying normal studies (specificity = 91.6% vs 78.9%), whereas both groups had similar accuracy in identifying abnormal studies (sensitivity = 82.3% vs 85.2%). There was higher agreement amongst surgeons than amongst radiologists when determining wrap position (κ = 0.65 vs 0.54). Both groups had low agreement when classifying a wrap migration as partial or total (κ = 0.33 vs 0.06). Radiologists were more likely to interpret the position of the wrap as abnormal (relative risk = 1.25) while surgeons reported a greater degree of hold-up of contrast at the gastro-oesophageal junction (mean score = 1.17 vs 0.86).

CONCLUSION

Radiologists would benefit from more information about the technical details of laparoscopic anti-reflux surgery. Standardised protocols for performing post-fundoplication contrast studies are needed.

Impact of ineffective oesophageal motility and wrap type on dysphagia after laparoscopic fundoplication

BACKGROUND

Laparoscopic 360° fundoplication is the most common operation for gastro-oesophageal reflux disease, but is associated with postoperative dysphagia in some patients. Patients with ineffective oesophageal motility may have a higher risk of developing postoperative dysphagia, but this remains unclear.

METHODS

From 1991 to 2010, 2040 patients underwent primary laparoscopic fundoplication for gastro-oesophageal reflux disease and met the study inclusion criteria; 343 had a 90°, 498 a 180° and 1199 a 360° fundoplication. Primary peristalsis and distal contraction amplitude during oesophageal manometry were determined for 1354 patients. Postoperative dysphagia scores (range 0-45) were recorded at 3 and 12 months, then annually. Oesophageal dilatations and/or reoperations for dysphagia were recorded.

RESULTS

Preoperative oesophageal motility did not influence postoperative dysphagia scores, the need for dilatation and/or reoperation up to 6 years. Three-month dysphagia scores were lower after 90° and 180° compared with 360° fundoplication (mean(s.e.m.) 8·0(0·6) and 9·8(0·5) respectively versus 11·9(0·4); P < 0·001 and P = 0·003), but these differences diminished after 6 years of follow-up. The incidence of dilatation and reoperation for dysphagia was lower after 90° (2·6 and 0·6 per cent respectively) and 180° (4·4 and 1·0 per cent) fundoplications than with a 360° wrap (9·8 and 6·8 per cent; both P < 0·001 versus 90° and 180° groups).

CONCLUSION

Tailoring the degree of fundoplication according to preoperative oesophageal motility by standard manometric parameters has no long-term impact on postoperative dysphagia. There is, however, a proportionate increase in short-term dysphagia scores with increasing degree of wrap, and a corresponding proportionate increase in dilatations and reoperations for dysphagia. These differences in dysphagia scores diminish with time.

Diffuse esophageal leiomyomatosis

Progressive dysphagia of unknown etiology may still provide a diagnostic challenge despite an increase in the number and quality of investigations available. We describe a 64-year-old man who presented with progressive dysphagia and weight loss. Following a number of investigations, a diagnosis of diffuse esophageal leiomyomatosis was made and the patient was treated appropriately.

The discovery of tertiary-amine LXR agonists with potent cholesterol efflux activity in macrophages

The liver X receptors (LXR) play a key role in cholesterol homeostasis and lipid metabolism. SAR studies around tertiary-amine lead molecule 2, an LXR full agonist, revealed that steric and conformational changes to the acetic acid and propanolamine groups produce dramatic effects on agonist efficacy and potency. The new analogs possess good functional activity, demonstrating the ability to upregulate LXR target genes, as well as promote cholesterol efflux in macrophages.

Discovery of orally active, pyrrolidinone-based progesterone receptor partial agonists

We have designed and synthesized a novel series of pyrrolidinones as progesterone receptor partial agonists. Compounds from this series had improved AR selectivity, rat pharmacokinetic properties, and in vivo potency compared to the lead compound. In addition, these compounds had improved selectivity against hERG channel inhibition.

Risk prediction scores for postoperative mortality after esophagectomy: validation of different models

BACKGROUND

Different prediction models for operative mortality after esophagectomy have been developed. The aim of this study is to independently validate prediction models from Philadelphia, Rotterdam, Munich, and the ASA.

METHODS

The scores were validated using logistic regression models in two cohorts of patients undergoing esophagectomy for cancer from Switzerland (n = 170) and Australia (n = 176).

RESULTS

All scores except ASA were significantly higher in the Australian cohort. There was no significant difference in 30-day mortality or in-hospital death between groups. The Philadelphia and Rotterdam scores had a significant predictive value for 30-day mortality (p = 0.001) and in-hospital death (p = 0.003) in the pooled cohort, but only the Philadelphia score had a significant prediction value for 30-day mortality in both cohorts. Neither score showed any predictive value for in-hospital death in Australians but were highly significant in the Swiss cohort. ASA showed only a significant predictive value for 30-day mortality in the Swiss. For in-hospital death, ASA was a significant predictor in the pooled and Swiss cohorts. The Munich score did not have any significant predictive value whatsoever.

CONCLUSION

None of the scores can be applied generally. A better overall predictive score or specific prediction scores for each country should be developed.

Long-term outcomes of revisional surgery following laparoscopic fundoplication

Background

A small proportion of patients who have laparoscopic antireflux procedures require revisional surgery. This study investigated long-term clinical outcomes.

Methods

Patients requiring late revisional surgery following laparoscopic fundoplication for gastro-oesophageal reflux were identified from a prospective database. Long-term outcomes were determined using a questionnaire evaluating symptom scores for heartburn, dysphagia and satisfaction.

Results

The database search found 109 patients, including 98 (5·6 per cent) of 1751 patients who had primary surgery in the authors' unit. Indications for surgical revision were dysphagia (52 patients), recurrent reflux (36), mechanical symptoms related to paraoesophageal herniation (16) and atypical symptoms (five). The median time to revision was 26 months. Outcome data were available for 104 patients (median follow-up 66 months) and satisfaction data for 102, 88 of whom were highly satisfied (62·7 per cent) or satisfied (23·5 per cent) with the outcome. Patients who had revision for dysphagia had a higher incidence of poorly controlled heartburn (20 versus 2 per cent; P = 0·004), troublesome dysphagia (16 versus 6 per cent; P = 0·118) and a lower satisfaction score (P = 0·023) than those with recurrent reflux or paraoesophageal herniation.

Conclusion

Revisional surgery following laparoscopic fundoplication can produce good long-term results, but revision for dysphagia has less satisfactory outcomes.

Synthesis and SAR of potent LXR agonists containing an indole pharmacophore

A novel series of 1H-indol-1-yl tertiary amine LXR agonists has been designed. Compounds from this series were potent agonists with good rat pharmacokinetic parameters. In addition, the crystal structure of an LXR agonist bound to LXRalpha will be disclosed.

Detection of lymph node metastases in oesophageal cancer

Background

The importance of lymph node status in oesophageal cancer cannot be disputed. It is therefore surprising that no standardization exists in either terminology or methodology in lymph node analysis.

Methods

All online databases were searched to identify articles published from 1970 onwards. This was supplemented by hand searching references of retrieved articles.

Results and conclusion

Without accurate identification of lymph node metastases, patients cannot be staged properly, nor can best practice for the treatment of oesophageal cancer be determined. This review outlines the problem and proposes recommendations for standardization in terminology and methodology for the detection of lymph node metastases in oesophageal cancer.

Development of a small-molecule serum- and glucocorticoid-regulated kinase-1 antagonist and its evaluation as a prostate cancer therapeutic

Androgens, through their actions on the androgen receptor (AR), are required for the development of the prostate and contribute to the pathologic growth dysregulation observed in prostate cancers. Consequently, androgen ablation has become an essential component of the pharmacotherapy of prostate cancer. In this study, we explored the utility of targeting processes downstream of AR as an alternate approach for therapy. Specifically, we show that the serum and glucocorticoid-regulated kinase 1 (SGK1) gene is an androgen-regulated target gene in cellular models of prostate cancer. Furthermore, functional serum- and glucocorticoid-regulated kinase 1 (SGK1) protein, as determined by the phosphorylation of its target Nedd4-2, was also increased with androgen treatment. Importantly, we determined that RNA interference-mediated knockdown of SGK1 expression attenuates the androgen-mediated growth of the prostate cancer cell line LNCaP. Given these findings, we explored the utility of SGK1 as a therapeutic target in prostate cancer by developing and evaluating a small-molecule inhibitor of this enzyme. From these studies emerged GSK650394, a competitive inhibitor that quantitatively blocks the effect of androgens on LNCaP cell growth. Thus, in addition to androgen ablation, inhibition of pathways downstream of AR is likely to have therapeutic utility in prostate cancer.

Highly Potent Inhibitors of Methionine Aminopeptidase-2 Based on a 1,2,4-Triazole Pharmacophore

High-throughput screening for inhibitors of the human metalloprotease, methionine aminopeptidase-2 (MetAP2), identified a potent class of 3-anilino-5-benzylthio-1,2,4-triazole compounds. Efficient array and interative synthesis of triazoles led to rapid SAR development around the aniline, benzylthio, and triazole moeities. Evaluation of these analogs in a human MetAP2 enzyme assay led to the identification of several inhibitors with potencies in the 50-100 picomolar range. The deleterious effects on inhibitor potency by methylation of the anilino-triazole nitrogens, as well as the X-ray crystal structure of triazole 102 bound in the active site of MetAP2, confirm the key interactions between the triazole nitrogens, the active site cobalt atoms, and the His-231 side-chain. The structure has also provided a rationale for interpreting SAR within the triazole series. Key aniline (2-isopropylphenyl) and sulfur substituents (furanylmethyl) identified in the SAR studies led to the identification of potent inhibitors (103 and 104) of endothelial cell proliferation. Triazoles 103 and 104 also exhibited dose-dependent activity in an aortic ring tissue model of angiogenesis highlighting the potential utility of MetAP2 inhibitors as anticancer agents.

A Structural and in Vitro Characterization of Asoprisnil: A Selective Progesterone Receptor Modulator

Selective progesterone receptor modulators (SPRMs) have been suggested as therapeutic agents for treatment of gynecological disorders. One such SPRM, asoprisnil, was recently in clinical trials for treatment of uterine fibroids and endometriosis. We present the crystal structures of progesterone receptor (PR) ligand binding domain complexed with asoprisnil and the corepressors nuclear receptor corepressor (NCoR) and SMRT. This is the first report of steroid nuclear receptor crystal structures with ligand and corepressors. These structures show PR in a different conformation than PR complexed with progesterone (P4). We profiled asoprisnil in PR-dependent assays to understand further the PR-mediated mechanism of action. We confirmed previous findings that asoprisnil demonstrated antagonism, but not agonism, in a PR-B transfection assay and the T47D breast cancer cell alkaline phosphatase activity assay. Asoprisnil, but not RU486, weakly recruited the coactivators SRC-1 and AIB1. However, asoprisnil strongly recruited the corepressor NCoR in a manner similar to RU486. Unlike RU486, NCoR binding to asoprisnil-bound PR could be displaced with equal affinity by NCoR or TIF2 peptides. We further showed that it weakly activated T47D cell gene expression of Sgk-1 and PPL and antagonized P4-induced expression of both genes. In rat leiomyoma ELT3 cells, asoprisnil demonstrated partial P4-like inhibition of cyclooxygenase (COX) enzymatic activity and COX-2 gene expression. In the rat uterotrophic assay, asoprisnil demonstrated no P4-like ability to oppose estrogen. Our data suggest that asoprisnil differentially recruits coactivators and corepressors compared to RU486 or P4, and this specific cofactor interaction profile is apparently insufficient to oppose estrogenic activity in rat uterus.

Microtia Reconstruction

Success in microtia surgery requires meticulous patient education, planning, technique, and follow-through. When these principles are followed, excellent results as well as tremendous satisfaction are achievable for both the patient and surgeon.

Infectious Mononucleosis and Corticosteroids

OBJECTIVE

Although many studies have examined the effects of systemic corticosteroid therapy (SCT) on the clinical course of infectious mononucleosis (IM), few have evaluated the influence of these studies on treatment patterns and outcomes. The purpose of this study was to review current therapeutic strategies and outcomes in uncomplicated and complicated IM.

DESIGN

Retrospective case series.

SETTING

Tertiary care center.

PATIENTS

We identified 206 immunocompetent patients with IM diagnosed during the previous 5 years. Patient information, including age, sex, history and physical findings at presentation, pertinent laboratory data, management practices, and treatment outcomes, were analyzed.

INTERVENTIONS

Systemic corticosteroid therapy was used in 44.7% of patients. Evaluation of treatment indications for SCT revealed that 8.0% of the study population qualified by traditional criteria for the use of corticosteroids; 92.0% of patients received SCT for other indications. Factors associated with the observed increase in corticosteroid use included a history of repeat visits, inpatient admission, and otolaryngology consultation.

MAIN OUTCOME MEASURES

Diagnosis was made on the basis of a positive heterophil antibody test (monospot test) with appropriate clinical findings (97.5% of patients) or by the presence of lymphocytosis with appropriate clinical findings (2.4% of patients).

RESULTS

Systemic corticosteroid therapy was not positively associated with fever, decreased oral intake, tonsillar hypertrophy, or duration of symptoms. No significant differences in incidence of disease complications, rates of hospital admission, or length of hospital stay were noted between the steroid and nonsteroid treatment groups.

CONCLUSIONS

Despite consistent and uniform acceptance in the medical literature that SCT in the setting of IM should be reserved for patients with impending airway obstruction, corticosteroids continue to be used on a much broader scale at this tertiary care institution. This observation suggests that clinicians see value in SCT for treatment of IM beyond the classically accepted reasons. Moreover, despite previous reports of possible adverse consequences of SCT in IM, our review failed to demonstrate any such trend.

4-Aryl-1,2,3-triazole: A Novel Template for a Reversible Methionine Aminopeptidase 2 Inhibitor, Optimized To Inhibit Angiogenesis in Vivo

Inhibitors of human methionine aminopeptidase type 2 (hMetAP2) are of interest as potential treatments for cancer. A new class of small molecule reversible inhibitors of hMetAP2 was discovered and optimized, the 4-aryl-1,2,3-triazoles. Compound 24, a potent inhibitor of cobalt-activated hMetAP2, also inhibits human and mouse endothelial cell growth. Using a mouse matrigel model, this reversible hMetAP2 inhibitor was also shown to inhibit angiogenesis in vivo.

Discovery of Substituted Maleimides as Liver X Receptor Agonists and Determination of a Ligand-Bound Crystal Structure

Substituted 3-(phenylamino)-1H-pyrrole-2,5-diones were identified from a high throughput screen as inducers of human ATP binding cassette transporter A1 expression. Mechanism of action studies led to the identification of GSK3987 as an LXR ligand. GSK3987 recruits the steroid receptor coactivator-1 to human LXRalpha and LXRbeta with EC(50)s of 40 nM, profiles as an LXR agonist in functional assays, and activates LXR though a mechanism that is similar to first generation LXR agonists.

Synthetic LXR agonists increase LDL in CETP species

Liver X receptor (LXR) nuclear receptors regulate the expression of genes involved in whole body cholesterol trafficking, including absorption, excretion, catabolism, and cellular efflux, and possess both anti-inflammatory and antidiabetic actions. Accordingly, LXR is considered an appealing drug target for multiple indications. Synthetic LXR agonists demonstrated inhibition of atherosclerosis progression in murine genetic models; however, these and other studies indicated that their major undesired side effect is an increase of plasma and hepatic triglycerides. A significant impediment to extrapolating results with LXR agonists from mouse to humans is the absence in mice of cholesteryl ester transfer protein, a known LXR target gene, and the upregulation in mice but not humans of cholesterol 7alpha-hydroxylase. To better predict the human response to LXR agonism, two synthetic LXR agonists were examined in hamsters and cynomolgus monkeys. In contrast to previously published results in mice, neither LXR agonist increased HDL-cholesterol in hamsters, and similar results were obtained in cynomolgus monkeys. Importantly, in both species, LXR agonists increased LDL-cholesterol, an unfavorable effect not apparent from earlier murine studies. These results reveal additional problems associated with current synthetic LXR agonists and emphasize the importance of profiling compounds in preclinical species with a more human-like LXR response and lipoprotein metabolism.

Discovery of non-steroidal mifepristone mimetics: Pyrazoline-based PR antagonists

Mifepristone is a non-selective antagonist of 3-oxosteroid receptors with both abortifacient and anti-endometriotic activities. Non-steroidal mimetics of mifepristone and progesterone are important templates for modulation of the progesterone receptor (PR). For our PR program, we sought an unexplored, synthetically accessible non-steroidal mimetic of mifepristone, suitable for parallel synthesis of analogues. Docking of compounds into a PR homology model identified 4-substituted pyrazolines, which, when synthesized and tested, exhibited functional antagonism of PR.

External auditory canal foreign body removal: management practices and outcomes

OBJECTIVES/HYPOTHESIS

The purpose of the study was to evaluate the effectiveness of external auditory canal foreign body removal attempts by health care practitioners and to explore outcomes of patients with unsuccessful initial removal attempts.

STUDY DESIGN

Retrospective case series.

METHODS

A case series of patients presenting with external auditory canal foreign body to the emergency department of the authors' institution (Strong Memorial Hospital, University of Rochester Medical Center) over a 3-year period was studied retrospectively. Medical records were reviewed, and information including age at presentation, type of foreign body, side of presentation, length of time in place, signs and symptoms at presentation, management practices, and outcomes was recorded.

RESULTS

One hundred sixty-two patients with a diagnosis of external auditory canal foreign body were identified. Emergency personnel successfully managed 67% of patients using direct visualization techniques, and 33% required otolaryngological consultation. Otolaryngologists used otomicroscopy with standard otological instruments as their mainstay of management. Analysis of successfully managed emergency department cases revealed that 82% of foreign bodies were irregularly shaped objects with soft, graspable parts. Conversely, 72% of foreign bodies in otolaryngology referrals were firm, rounded objects such as beads and beans. Analysis of patients referred to otolaryngologists revealed a requirement for removal under anesthesia of 19%. Patients with a history of one or more removal attempts before emergency department evaluation universally failed further direct visualization techniques. A disproportionate number of these patients eventually required operative intervention and/or had tympanic membrane perforation. Patients with a history of previous removal attempt(s) who were referred directly to otolaryngologists were more likely to be successfully managed without general anesthesia.

CONCLUSION

Emergency room personnel successfully manage the majority of patients with foreign bodies of the external auditory canal. For patients with firm, rounded objects, direct otolaryngology consultation without further manipulation should be strongly considered. Patients who have had previous removal attempts should not undergo further manipulation in the emergency department but rather should be referred directly to an otolaryngologist.

Comparison of an amorphous silicon/cesium iodide flat-panel digital chest radiography system with screen/film and computed radiography systems--a contrast-detail phantom study

Flat-panel (FP) based digital radiography systems have recently been introduced as a new and improved digital radiography technology; it is important to evaluate and compare this new technology with currently widely used conventional screen/film (SF) and computed radiography (CR) techniques. In this study, the low-contrast performance of an amorphous silicon/cesium iodide (aSi/Csl)-based flat-panel digital chest radiography system is compared to those of a screen/film and a computed radiography system by measuring their contrast-detail curves. Also studied were the effects of image enhancement in printing the digital images and dependence on kVp and incident exposure. It was found that the FP system demonstrated significantly better low-contrast performance than the SF or CR systems. It was estimated that a dose savings of 70%-90% could be achieved to match the low-contrast performance of the FP images to that of the SF images. This dose saving was also found to increase with the object size. No significant difference was observed in low-contrast performances between the SF and CR systems. The use of clinical enhancement protocols for printing digital images was found to be essential and result in better low-contrast performance. No significant effects were observed for different kVps. From the results of this contrast-detail phantom study, the aSi/CsI-based flat-panel digital chest system should perform better under clinical situations for detection of low-contrast objects such as lung nodules. However, proper processing prior to printing would be essential to realizing this better performance.

Steady-state kinetic characterization of substrates and metal-ion specificities of the full-length and N-terminally truncated recombinant human methionine aminopeptidases (type 2)

The steady-state kinetics of a full-length and truncated form of the type 2 human methionine aminopeptidase (hMetAP2) were analyzed by continuous monitoring of the amide bond cleavage of various peptide substrates and methionyl analogues of 7-amido-4-methylcoumarin (AMC) and p-nitroaniline (pNA), utilizing new fluorescence-based and absorbance-based assay substrates and a novel coupled-enzyme assay method. The most efficient substrates for hMetAP2 appeared to be peptides of three or more amino acids for which the values of k(cat)/K(m) were approximately 5 x 10(5) M(-1) min(-1). It was found that while the nature of the P1' residue of peptide substrates dictates the substrate specificity in the active site of hMetAP2, the P2' residue appears to play a key role in the kinetics of peptidolysis. The catalytic efficiency of dipeptide substrates was found to be at least 250-fold lower than those of the tripeptides. This substantially diminished catalytic efficiency of hMetAP2 observed with the alternative substrates MetAMC and MetpNA is almost entirely due to the reduction in the turnover rate (k(cat)), suggesting that cleavage of the amide bond is at least partially rate-limiting. The 107 N-terminal residues of hMetAP2 were not required for either the peptidolytic activity of the enzyme or its stability. Steady-state kinetic comparison and thermodynamic analyses of an N-terminally truncated form and full-length enzyme yielded essentially identical kinetic behavior and physical properties. Addition of exogenous Co(II) cation was found to significantly activate the full-length hMetAP2, while Zn(II) cation, on the other hand, was unable to activate hMetAP2 under any concentration that was tested.

The therapeutic potential of advances in cysteine protease inhibitor design

Cysteine proteases are attracting increased attention for therapeutic intervention by inhibitors because of an increased recognition of specific processing functions in both mammals and microbes. New advances in inhibitor design have been made for both reversible and irreversible classes. Reversible inhibitors may incorporate a covalent bond formation that can contribute an element of selectivity relative to serine protease inhibition. Ketones of low intrinsic reactivity are especially attractive agents, with potential for chronic therapeutic use. Effectively irreversible inhibition can be achieved with slow or single turnover substrates. This approach eliminates any reactivity toward non-enzyme nucleophiles. Only mechanistically related enzyme targets will be irreversibly blocked in an in vivo setting, thereby resulting in a safer type of inhibitor.

Performance analysis of a new semiorthogonal spline wavelet compression algorithm for tonal medical images

Lossy image compression is thought to be a necessity as radiology moves toward a filmless environment. Compression algorithms based on the discrete cosine transform (DCT) are limited due to the infinite support of the cosine basis function. Wavelets, basis functions that have compact or nearly compact support, are mathematically better suited for decorrelating medical image data. A lossy compression algorithm based on semiorthogonal cubic spline wavelets has been implemented and tested on six different image modalities (magnetic resonance, x-ray computed tomography, single photon emission tomography, digital fluoroscopy, computed radiography, and ultrasound). The fidelity of the reconstructed wavelet images was compared to images compressed with a DCT algorithm for compression ratios of up to 40:1. The wavelet algorithm was found to have generally lower average error metrics and higher peak-signal-to-noise ratios than the DCT algorithm.

Design and synthesis of diaminopyrrolidinone inhibitors of human osteoclast cathepsin K

The structure-based design and synthesis of lactam-constrained azapeptide inhibitors of human cathepsin K are described. Enhanced stability to proteolytic cleavage over acyclic analogues is discussed.

Atypical glandular cells of undetermined significance on cervical smears. A study with cytohistologic correlation

OBJECTIVE

The incidence of endocervical adenocarcinoma has increased steadily over the past two decades. Since the Bethesda System was introduced, the diagnosis of atypical glandular cells of undetermined significance (AGUS) has also risen and now accounts for 0.46-1.83% of all cervical (Pap) smears. The purpose of this study was to evaluate the significance of a diagnosis of AGUS using cytohistologic correlation.

STUDY DESIGN

A retrospective review of archival material from 1993 through 1996 identified 64 patients who had smears diagnosed as AGUS and had a subsequent surgical biopsy. The smears were reviewed and cytologic features analyzed and correlated with the histologic diagnosis.

RESULTS

On biopsy, 3 (5%) of the 64 cases showed endocervical adenocarcinoma in situ (AIS) (1 case with invasive adenocarcinoma also), 14 (22%) had a benign glandular lesion (endocervical polyp, tubal metaplasia, microglandular hyperplasia, reactive changes), 35 (54%) had squamous intraepithelial lesion (SIL) (15 diagnosed on the original smear), and 12 (19%) had no abnormality. Among the cytologic criteria evaluated, feathering (P = .01), palisading (P < .001) and chromatin clearing (P = .002) were shown to have a significant association with the histopathologic diagnosis of AIS/adenocarcinoma. These features were also useful in distinguishing AIS/adenocarcinoma from SIL and benign glandular changes from AIS/adenocarcinoma but not benign/reactive glandular changes from SIL.

CONCLUSION

A diagnosis of AGUS correlated with a clinically significant lesion in the majority of cases. Squamous dysplasia (SIL) was the most common lesion identified. The presence of feathering, nuclear palisading and chromatin clearing increased the likelihood of a histologic diagnosis of AIS/adenocarcinoma.