Regulation of mast cells by overlapping but distinct protein interactions of Siglec-6 and Siglec-8

BACKGROUND

Sialic acid-binding immunoglobulin-like lectin (Siglec)-6 and Siglec-8 are closely related mast cell (MC) receptors with broad inhibitory activity, but whose functional differences are incompletely understood.

METHODS

Proteomic profiling using quantitative mass spectrometry was performed on primary mouse MCs to identify proteins associated with Siglec-6 and Siglec-8. For functional characterization, each receptor was evaluated biochemically and in ex vivo and in vivo inhibition models of IgE and non-IgE-mediated MC activation in Siglec-6- or Siglec-8-expressing transgenic mice.

RESULTS

Siglec-6 and Siglec-8 were found in MCs within large complexes, interacting with 66 and 86 proteins, respectively. Strikingly, Siglec-6 and Siglec-8 interacted with a large cluster of proteins involved in IgE and non-IgE-mediated MC activation, including the high affinity IgE receptor, stem cell factor (SCF) receptor KIT/CD117, IL-4 and IL-33 receptors, and intracellular kinases LYN and JAK1. Protein interaction networks revealed Siglec-6 and Siglec-8 had overlapping yet distinct MC functions, with a potentially broader regulatory role for Siglec-6. Indeed, Siglec-6 preferentially interacted with the mature form of KIT at the cell surface, and treatment with an anti-Siglec-6 antibody significantly inhibited SCF-mediated MC activation more in comparison to targeting Siglec-8.

CONCLUSION

These data demonstrate a central role for Siglec-6 and Siglec-8 in controlling MC activation through interactions with multiple activating receptors and key signaling molecules. Our findings suggest that Siglec-6 has a role distinct from that of Siglec-8 in regulating MC function and represents a distinct potential therapeutic target in mast cell-driven diseases.

Functional and Phenotypic Characterization of Siglec-6 on Human Mast Cells

Mast cells are tissue-resident cells that contribute to allergic diseases, among others, due to excessive or inappropriate cellular activation and degranulation. Therapeutic approaches to modulate mast cell activation are urgently needed. Siglec-6 is an immunoreceptor tyrosine-based inhibitory motif (ITIM)-bearing receptor selectively expressed by mast cells, making it a promising target for therapeutic intervention. However, the effects of its engagement on mast cells are poorly defined. Siglec-6 expression and endocytosis on primary human mast cells and mast cell lines were assessed by flow cytometry. SIGLEC6 mRNA expression was examined by single-cell RNAseq in esophageal tissue biopsy samples. The ability of Siglec-6 engagement or co-engagement to prevent primary mast cell activation was determined based on assessments of mediator and cytokine secretion and degranulation markers. Siglec-6 was highly expressed by all mast cells examined, and the SIGLEC6 transcript was restricted to mast cells in esophageal biopsy samples. Siglec-6 endocytosis occurred with delayed kinetics relative to the related receptor Siglec-8. Co-crosslinking of Siglec-6 with FcεRIα enhanced the inhibition of mast cell activation and diminished downstream ERK1/2 and p38 phosphorylation. The selective, stable expression and potent inhibitory capacity of Siglec-6 on human mast cells are favorable for its use as a therapeutic target in mast cell-driven diseases.

Erratum to: Topical issue on Lattice Field Theory during the Covid-19 pandemic

[This corrects the article DOI: 10.1140/epja/s10050-021-00614-5.].

The Inhibitory Receptor Siglec-8 Interacts With FcεRI and Globally Inhibits Intracellular Signaling in Primary Mast Cells Upon Activation

Immunomodulation of mast cell (MC) activity is warranted in allergic and inflammatory diseases where MCs have a central role in pathogenesis. Targeting Siglec-8, an inhibitory receptor on MCs and eosinophils, has shown promising activity in preclinical and clinical studies. While the intracellular pathways that regulate Siglec-8 activity in eosinophils have been well studied, the signaling mechanisms that lead to MC inhibition have not been fully elucidated. Here, we evaluate the intracellular signaling pathways of Siglec-8-mediated inhibition in primary MCs using an anti-Siglec-8 monoclonal antibody (mAb). Phospho-proteomic profiling of FcεRI-activated MCs revealed Siglec-8 mAb-treatment globally inhibited proximal and downstream kinases, leading to attenuated MC activation and degranulation. In fact, Siglec-8 was found to directly interact with FcεRI signaling molecules. Siglec-8 inhibition was dependent on both cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that interact with the SH2 containing protein phosphatase Shp-2 upon Siglec-8 phosphorylation. Taken together, these data support a model in which Siglec-8 regulates proximal FcεRI-induced phosphorylation events through phosphatase recruitment and interaction with FcεRIγ, resulting in global inhibition of MCs upon Siglec-8 mAb engagement.

75 Parental perspective about the health and development of their extremely preterm child

Primary Subject area

Neonatal-Perinatal Medicine

Background

Preterm birth outcome studies and clinical follow-up have traditionally focused on neurodevelopment. We previously showed in a selected sample of parents that they also valued other types of outcomes.

Objectives

This study aimed to validate these findings in a more diverse cohort by examining parental perspectives about the positive and negative aspects of their very preterm child’s health and development in relation to level of neurodevelopment impairment (NDI).

Design/Methods

Parents of children born < 29 weeks gestational age in 2016-2018 and seen at two Canadian neonatal follow-up clinics were invited to complete an online survey about their level of agreement with statements about their child’s health, development, and well-being. Parental responses in relation to their child’s level of NDI were examined using Kruskal-Wallis and chi-square for trends tests.

Results

199 parental responses were obtained for 165 children (65% of eligible children). Of these children, 52%, 27% and 21% had, respectively, no, mild to moderate, and severe NDI. Development was the most common source of concerns (49%), followed by the child’s future (35%), and physical health (35%). Parents of children with severe NDI were more likely to express concerns than those with mild to moderate or no NDI. Parents rated their child’s health relatively high with a median score of 8/10 (range 3-10). Children with no NDI were given higher scores than those with NDI (p = 0.004). Regardless of level of NDI, almost all parents agreed with their child being happy (p = 1.000) and having a positive personality (p = 0.207). Figure 1 shows that parental concerns increased with level of NDI.

Conclusion

Parents of preterm children have a balanced perspective on their child’s outcome. Integrating their views when developing core sets of important outcomes for neonatal follow-up is critical.

21 Long-Term Ophthalmologic Outcome of Young Adults Born Extremely Preterm

Primary Subject area

Ophthalmology

Background

Retinopathy of prematurity (ROP) remains the dominant cause of severe visual impairment in childhood in North America and Europe. With the salient improvement in neonatal care since the 1980s, more and more very/extremely premature infants survived and are now reaching adulthood. Premature birth interferes with the critical period of retinal maturation and foveal development. The development of ROP further damages the retina and its vasculature. So far, outcome studies on visual functions and ocular structure in adults born preterm remain scarce.

Objectives

The first aim of this study is to describe the visual function and retinal structure in a cohort of young adults who were born prematurely. With the recognition of the insidious nature of ROP, we also aimed to investigate if ROP could exert a “second hit” beyond prematurity.

Design/Methods

This cross-sectional observational study compared visual function of young adults (18-29 years old) born prematurely (< 30 weeks of gestational age [GA]) versus full-term controls. Participants were categorized into three groups: preterm without ROP, preterm with ROP, and term. Comprehensive ophthalmologic examination was performed with blinding to preterm and ROP status. Best corrected visual acuity (BCVA) was assessed with a standardized linear Snellen chart and contrast sensitivity (CS) with the Vistech system. When analyzing BCVA, refractive errors, and contrast sensitivities, we further grouped data based on the strong eyes (better BCVA) and the weak eyes (worse BCVA). Area-under-the-curve (AUC) analysis was performed to gauge the overall CS. Group comparisons were done using ANOVA.

Results

In this study, 88 individuals born prematurely and 86 individuals born full-term were recruited. Among the strong eyes of the 3 groups, there was no significant difference for BCVA or refractive errors (see image). Among the weak eyes, the preterm with ROP group had the worst BCVA and refractive outcomes, compared to the preterm without ROP and term groups. In the strong eyes, the CS AUC of the preterm with ROP group (16.22 ± 2.69 p<0.0001) was significantly lower than both the preterm without ROP (18.13 ± 2.01) and term (19.55 ± 2.48) groups. In the weak eyes, the AUC of the 3 groups showed a significant and progressive decline from the term group (18.9 ± 2.84) to the preterm without ROP group (18.29 ± 2.14), then to the preterm with ROP group (15.24 ± 2.21).

Conclusion

In our cohort of young adults born preterm, prematurity alone did not affect their BCVA and refractive errors. However, ROP was independently associated with a lower BCVA, higher refractive errors, and a reduced contrast sensitivity. Our data have shown that prematurity and ROP have independent effects on contrast sensitivity. This study highlights the necessity of long-term ophthalmologic follow-ups for adults who were born prematurely.

Mast Cell and Eosinophil Activation Are Associated With COVID-19 and TLR-Mediated Viral Inflammation: Implications for an Anti-Siglec-8 Antibody

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection represents a global health crisis. Immune cell activation via pattern recognition receptors has been implicated as a driver of the hyperinflammatory response seen in COVID-19. However, our understanding of the specific immune responses to SARS-CoV-2 remains limited. Mast cells (MCs) and eosinophils are innate immune cells that play pathogenic roles in many inflammatory responses. Here we report MC-derived proteases and eosinophil-associated mediators are elevated in COVID-19 patient sera and lung tissues. Stimulation of viral-sensing toll-like receptors in vitro and administration of synthetic viral RNA in vivo induced features of hyperinflammation, including cytokine elevation, immune cell airway infiltration, and MC-protease production—effects suppressed by an anti-Siglec-8 monoclonal antibody which selectively inhibits MCs and depletes eosinophils. Similarly, anti-Siglec-8 treatment reduced disease severity and airway inflammation in a respiratory viral infection model. These results suggest that MC and eosinophil activation are associated with COVID-19 inflammation and anti-Siglec-8 antibodies are a potential therapeutic approach for attenuating excessive inflammation during viral infections.

Rapid Naloxone Administration Workshop for Health Care Providers at an Academic Medical Center

INTRODUCTION

Opioid overdose is a growing problem in the US. Often, residents are first responders to community and in-hospital opioid overdoses, and so, hands-on naloxone administration education is necessary. While residents get a brief algorithm on suspected opioid overdose during their mandatory American Heart Association basic life support training, there is a lack of hands-on standardized curricula on how to administer this lifesaving medication.

METHODS

To fill this gap, we developed a hands-on workshop for medical trainees on how to respond to an opioid overdose. Trainees who completed our workshop left with a first-responder naloxone kit using the Massachusetts statewide open prescription. All attendees were asked to take a voluntary pre- and posttraining survey.

RESULTS

A total of 80 trainees from a variety of specialties and training levels participated in this workshop. We were able to successfully link the pre- and postdata of 29 participants. Trainees were assessed on comfort in administering naloxone as a first responder and in teaching patients how to administer naloxone (via a 5-point Likert scale) and on percentage of time they prescribed naloxone to high-risk patient populations. We saw statistically significant increases in comfort in using naloxone and comfort in teaching patients to administer naloxone.

DISCUSSION

This innovative curriculum provides an adaptable, short, and effective workshop with hands-on practice for medical trainees at a variety of training levels. The workshop can efficiently train future health care professionals how to approach an opioid overdose.

Abstract P5-21-08: Tolerability of the combination of lapatinib and trastuzumab in older patients with HER2 positive metastatic breast cancer

Background: Older adults are less likely to be included in clinical trials leading to the approval of novel cancer treatments. The Institute of Medicine and ASCO have identified therapeutic phase II trials as a key research priority to increase the evidence base for older adults with cancer. While targeted therapies may represent a less toxic option for older patients, few trials have studied their tolerability and efficacy in older adults. Here, we present a phase II study (NCT01273610) of the combination of trastuzumab and lapatinib in older patients with HER2+ metastatic breast cancer (MBC), incorporating geriatric oncology principles in the study design.

Methods: Patients age ≥ 60 years with MBC and any number of prior chemotherapy (CT) lines received trastuzumab (either 4mg/kg loading dose followed by 2mg/kg weekly or 8mg/kg followed by 6mg/kg q/3 weeks) plus lapatinib 1000 mg/m2 daily in 21-day cycles. Patients completed a pre-treatment geriatric assessment including measures of function, comorbidity, cognition, nutrition, and psychosocial status. A toxicity risk score developed for older adults receiving cytotoxic CT was calculated for each patient (Hurria et al. JCO 2011 & 2016). Relationships between tolerability (dose reductions and grade (G) ≥ 3 toxicity attributed to treatment) and risk score analyzed using a log2 transformation were assessed using generalized linear models, Student's t tests, and Fisher's exact test. Response rate (RR) and progression free survival (PFS) were evaluated.

Results: 40 patients (mean age 72 [60-92]) were accrued from 04/11 to 05/15. 25% (n = 10) were ≥ 75 years of age. 65% of patients (n = 26) had HR+ tumors and 35% (n = 14) were receiving ≥ 3rd line treatment. Median number of cycles was 4 (0-28). RR was 23% (n = 9, 95% CI 11-38%; 1 complete, 8 partial). 23% (n = 9) achieved stable disease. PFS was 2.7 months (95% CI 2.5-12). Based on the toxicity risk score, 21% (n = 8), 54% (n = 21), and 26% (n = 10) were at low, intermediate, and high risk. 70% (n = 28) of patients had G ≥ 2 toxicities and 20% (n = 8) G ≥ 3 toxicities. G 2 and 3 diarrhea occurred in 28% (n = 11) and 5% (n = 2) respectively. 5% (n = 2) were hospitalized due to treatment-related toxicity. No G ≥ 3 cardiac toxicities were observed. 23% of patients (n = 9) had treatment delays, and 43% (n = 17) required a lapatinib dose reduction. The mean toxicity risk score was higher in patients who required dose reductions (Student's t: p = 0.02). No statistically significant relationship was found between toxicity risk scores and the presence of G ≥ 3 treatment toxicity (logistic regression: OR = 3.08, 95% CI [0.54, 21.2], p = 0.22).

Conclusions: Among older patients with MBC (79% at intermediate or high risk of G ≥ 3 cytotoxic CT toxicity), trastuzumab and lapatinib were well tolerated, with only 20% experiencing G3 toxicities. The toxicity risk score was not found to be significantly related with treatment toxicity, which may be explained by the very low incidence of G3 events. Patients with a low toxicity risk score were not likely to require a lapatinib dose reduction.

Citation Format: O'Connor T, Soto-Perez-de-Celis E, Blanchard S, Chapman A, Kimmick G, Muss H, Luu T, Waisman JR, Li D, Mortimer J, Yuan Y, Somlo G, Stewart D, Katheria V, Levi A, Hurria A. Tolerability of the combination of lapatinib and trastuzumab in older patients with HER2 positive metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-08.

Anticonvulsant Use in Treating Dementia-Related Agitation

Dementia is often accompanied by disturbances in behavior which require treatment with medications. Traditionally, antipsychotics and benzodiazepines have been used. Their modest beneficial effects must be balanced against toxicities such as drug-induced parkinsonism which leads to falls, and worsened cognitive function. Anticonvulsant medications have been used in the past to treat agitated and aggressive behaviors from various conditions. Recent reports attest to their usefulness in treating behavioral problems secondary to dementia. Carbamazepine and divalproex sodium have proven effective in treatment while newer agents like gabapentin may be useful as well. These agents may be preferable because they target a broad variety of symptoms and diseases, are less likely to induce extrapyramidal reactions and some have a low drug interaction profile.

Abstract P6-13-17: The combination of eribulin and everolimus results in enhanced suppression of tumors in mouse models of triple negative breast cancer

INTRODUCTION. Triple negative breast cancer (TNBC) is an aggressive form of breast cancer with poor overall and relapse free survival. TNBC does not have targeted or matched therapies. Patients have worse outcomes after chemotherapy than with other subtypes of breast cancer. TNBC accounts for 12-17% of all breast cancers, leaving an unmet need for targeted therapy. Efforts to profile these tumors have revealed several potential targets.

The PI3K/AKT/mTOR pathway is a signal transduction pathway that links growth related hormone receptor interaction to downstream targets such as AKT and mammalian target of rapamycin (mTOR). This pathway targets affect cell proliferation, survival, and apoptosis. Patients with TNBC have high levels of AKT expression and activation of this pathway.

Microtubule-targeting agents have been used in TNBC. Eribulin mesylate is a microtubule-targeting agent with benefits in treating taxane and anthracycline refractory breast cancer via a microtubule targeting anti-mitotic mechanism. It has been approved for the treatment of TNBC in heavily pretreated patients.

Despite targeted therapy, breast cancer cells can grow resistant. Targeting multiple cancer growth pathways has been used in patients that progress on therapy or fail to respond. We hypothesized that targeting both mitotic blockade and PI3K/AKT/mTOR pathway may provide enhanced suppression of TNBC growth in both syngeneic and xenogeneic mouse models.

MATERIALS AND METHODS. MDA-MB-468 is a human TNBC cell line. 4T1 is a highly metastatic mouse TNBC cell line derived from a spontaneously arising Balb/c mammary tumor. 4T1 and MDA-MB-468 tumor cells were injected into the mammary fat pad of female Balb/c and NOD/SCID/IL2Rgamma null (NSG) mice (with matrigel) respectively. After tumors were formed Balb/c mice were treated three times per week with vehicle, eribulin (0.75 mg/kg i.v.), RAD001 (5 mg/kg via oral gavage) or a combination of both. NSG mice were treated three times per week with vehicle, eribulin (0.5 mg/kg i.v.), RAD001 (5 mg/kg by oral gavage), or a combination of both. Tumor volumes and body weights were measured. Student t-test was used to compare the means of two groups and determine the p value (p<0.05 is significant). N=3-8 per group.

Table I. 4T1 mouse breast cancer modelTreatmentTumor Volume (mm3)+/-SEMVehicle511.6+/-56.82Eribulin445.6+/-92.17Everolimus324.9+/-24.55Combination171.4+/-16.07 p valueCombination vs. Vehicle0.0001Combination vs. Eribulin0.01Combination vs. Everolimus0.001

Table II. MDA-MB-468 human breast cancer cells in immune deficient mice.TreatmentTumor Volume (mm3)+/-SEMVehicle966.8+/-69.2Eribulin67.81+/-11.79Everolimus830.6+/-156.3Combination31.37+/-3.37 p valueCombination vs. Eribulin0.041Combination vs. Everolimus0.0076

RESULTS. In the 4T1 syngeneic breast cancer mouse model, the combination of Eribulin and Everolimus resulted in marked suppression of tumor growth which was statistically significant versus vehicle treatment alone, or Eribulin or Everolimus alone (Table I). In the MDA-MB-468 model, the combination of Eribulin and Everolimus demonstrated marked suppression of tumor growth which was statistically significant compared to either agent alone (Table II).

Citation Format: Marcinkowski E, Luu T, Yuan Y, Mortimer J, Leong L, Portnow J, Xing Q, Wen W, Yim J. The combination of eribulin and everolimus results in enhanced suppression of tumors in mouse models of triple negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-13-17.

Abstract P2-16-05: Efficacy of ABT-888 (veliparib) in patients with BRCA-associated breast cancer

Background: The potential for exploiting BRCA deficiencies with DNA repair inhibitors has both pre-clinical and clinical support. ABT-888 (veliparib), a DNA repair inhibitor initially thought to target Poly(ADP-Ribose) Polymerases (PARP), has demonstrated in vitro inhibition of BRCA1 and BRCA2 deficient mouse embryonic stell cells, with a larger effect on BRCA1 cells. We report on the pre-planned interim analysis of the efficacy of single agent veliparib in patients with either BRCA1 or BRCA2-associated stage IV breast cancer. Methods: BRCA 1 or 2 carrier patients with stage IV breast cancer, with measurable disease, without prior exposure to a PARP inhibitor or a platinum compound in the metastatic setting, were eligible. Velapirib was administered orally, at doses of 400 mg twice daily. Dose adjustments based on toxicity were permitted. Patients progressing on velapirib alone received carboplatin at an AUC of 5, IV, given Q 21 days, and velapirib 150 mg twice daily (the maximum tolerated dose [MTD] of the combination from our completed Phase I study: J Clin Oncol 30, 2012 [suppl; abstr 1024]). Patients were to be accrued from 7 NCI NO1- supported consortia. Initially 10 patients were to be accrued to each stratum (BRCA1 and BRCA2) to provide evidence of single agent activity. If there was sufficient activity to warrant consideration of velapirib as single agent therapy (defined as 2 or more confirmed partial [PR] or better responses out of 10 per stratum), an additional 12 patients would be accrued per stratum. Results: 20 evaluable patients (11 BRCA1 and 9 BRCA2 [1 in screening]) have been accrued, the majority with lung or liver as visceral metastatic sites of disease. Median age (range) is 46 (29-68) years. Tumors from 9 patients were hormone receptor positive. BRCA1 cohort: 4 of 11 patients are off treatment at a median of 2 months (1-4); 1 patient stopped velapirib due to toxicity (grade 2 rash/pruritus, grade 2 vomiting), 3 stopped for progressive disease (one with an unconfirmed PR). Seven patients are still on single agent veliparib with 1 unconfirmed PR, and 1 patient with two evaluations showing stable disease. BRCA2 cohort: 2 patients are off treatment at 2 months for progressive disease, 7 are still on treatment with 1 confirmed PR, and 3 unconfirmed PRs. Data on patients receiving combination of velapirib and carboplatin after progression is too early. Treatment-related toxicity is being updated and has so far been reported from 14 patients: 1 patient had grade 3 fatigue, 1 patient with liver metastasis had both grade 3 alanine aminotransferase elevation and grade 3 abdominal pain. Grade 2 toxicities occurring in more than 1 patient included nausea/vomiting (6 patients), chills (2 patients), and fatigue (2 patients). Conclusion: Velapirib has single agent activity in both BRCA1 and BRCA2-associated stage IV breast cancer patients, and is well-tolerated. Mature response, treatment, and toxicity data will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-05.

Abstract P6-11-12: CNS metastases in breast cancer: A comparison report

Background: Breast cancer is one of the most common causes of central nervous system (CNS) metastases, with 25-34% of patients experiencing brain metastases. Typically, CNS metastasis is associated with a dismal survival largely due to the inability of chemotherapeutic and biologic agents to cross the blood-brain barrier. In the last 5 to 7 years the management of CNS metastases utilizing targeted therapies, stereotactic radiation, and craniotomy have all shown to improve survival. We reviewed and analyzed data for CNS metastastic breast cancer treated at City of Hope (COH), a tertiary cancer center in California, in two cohorts between 2000-2005 and 2006-2011 to compare their survival.

Methods/Results: A retrospective, comparative, correlational chart review was performed. Data from 172 women diagnosed with CNS metastases between 2000 and 2011 at COH, was evaluated. There were 47 patients in 2000-2005 and 125 patients in 2006-2011. The sample consisted of Caucasians (49.7%), Hispanics (26.1%), Asians (16.8%), and African Americans (7.4%). The median age at CNS diagnosis was 53 years old (24-87). Of these patients 38.2% were Her2neu positive, 30.6% ER/PR positive, and 21.4% triple negative (TN). In this cohort, the median survival for all patients with brain metastases is 5 months (0.03-85.6 months). The survival with brain metastasis among Her2neu positive, TN, and ER/PR positive is significantly different (8 months, 2.5 months, and, 5.3 months, respectively, p<0.0295). Limited sample size prevented the relatively substantial difference in patients with with Her2+ versus Her2- from reaching significance (median survival 8months vs 3.8 months respectively, p<0.0939). The median survival for patients diagnosed and treated in 2006-2011 is statistically significantly worse than those in 2000-20005 (4.4 months and 7 months, respectively, p = 0.0042). Most patients received treatment for brain metastases with one or more therapies, including whole brain radiation, stereotactic radiation, craniotomy, and intrathecal chemotherapy. Most of the patients who received chemotherapy, craniotomy, and/or stereotactic radiation were in the 2006-2011 group (100%, 82.5%, and 72.6%, respectively).There was also a shift in the incidence of patients with TN, her2neu positive, and ER/PR positive disease in the 2006-2011 as compared to 2000-2005 (24% vs 14.6%, p<0.004; 40% vs 31.3%, p<0.000; 31.2% vs 29.2%, p 0.033, respectively).

Conclusion: The results of our study showed that despite the new therapies there was no change in survival for brain metastasis in breast cancer. In this single institution report, this may be in part due to an increase number of patients with TN and Her2neu positive CNS disease, better data collection, or due to better systemic control. We also noted an increase in the number of patients with brain metastases, which may be attributed to the increase in the number of patients presenting with metastatic breast cancer at COH for consideration of investigational therapies. Further studies aimed to determine why there is a shift in the tumor biology, as well as, to characterize risk factors for development of CNS disease and to develop new treatment strategies are warranted.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-12.

Abstract P3-03-08: A comparison of PI3K inhibition by eribulin, other microtubule targeting agents and a DNA-damaging chemotherapeutic in triple negative and HER2 expressing breast cancer cell lines

Background. Eribulin is a microtubule-targeting agent with significant benefits in treating refractory metastatic breast cancer. Tumors from patients with Triple negative breast cancer (TNBC) have high levels of Akt expression and consistently show activation of the PI3K-mTOR pathway. Our objective was to compare Eribulin's ability to inhibit PI3K pathway activity and cell growth with two other microtubule targeting agents, Paclitaxel and Vinblastine, as well as a conventional DNA damaging chemotherapeutic Cisplatin.

Methods. MDA468 and BT549 TNBC cell lines and SKBR3 HER2 overexpressing breast cancer cell lines were used for this study. Western blot analysis was used to evaluate the expression of phosphorylated Akt-Ser473 (pAkt) and S6K1 (pS6K1) at different time points from 2 to 24 hours of treatment with Eribulin, Paclitaxel, Vinblastine, or Cisplatin. MTT assays were used to assess growth inhibition after 72 hours of treatment.

Results. Western blot analysis for MDA468 cells treated with Eribulin in varying concentrations confirm partial inhibition of pAkt expression as early as 4 hours at 100 pM concentration. Complete inhibition is reached at 50 nM. Partial inhibition of pS6K1 can be seen as early as 4 hours at 500 nM. Western analysis for MDA468 cells treated with Vinblastine in varying concentrations confirms inhibition of pAkt and pS6K1 beginning at 50 nM at 24 hours. Western analysis for MDA468 cells treated with Paclitaxel in varying concentrations showed increases in pAkt expression in a dose responsive fashion with significant increase in pAkt beginning at 5 nM concentration as well as increase in pS6K1 at 24 hours. Cisplatin markedly increases pAkt at 24 hours in a dose responsive fashion and decreases pS6K1 at 500 nM to 1000 nM concentration range in BT549. The IC50's for Eribulin ranged from 0.06 nM to 0.3 nM at 72 hours by MTT assay. The IC50's for Vinblastine ranged from 0.5 nM to 0.9 nM. Paclitaxel has reported IC50's in the 2 nM to 75 nM range in these cell lines, and Cisplatin has IC50's ranging from to ∼500 nM to ∼2000 nM at 72 hours in these cell lines.

Conclusion. Our study shows that for microtubule targeting agents such as Eribulin and Vinblastine that block polymerization of tubulin into microtubules, both pAkt and pS6K1 expression is suppressed. Growth inhibition is also confirmed, and is seen at doses when pAkt and pS6K1 are not suppressed. Eribulin inhibits pAkt and pS6K1 at lower concentrations than Vinblastine. With Paclitaxel, a microtubule-targeting agent that enhances polymerization of tubulin to microtubules, and Cisplatin, a conventional DNA damaging chemotherapeutic we observe an increase in pAkt expression, with variable effects on pS6K1. Enhancement of Akt activity is a likely survival response by cancer cells to chemotherapy, yet in the case of microtubule polymerization blockade as seen with Eribulin and Vinblastine, Akt activity is suppressed, along with downstream mTOR activity. The potential role of microtubule polymerization blockade in inhibition of the PI3K pathway needs further study. It may be a factor in the novel finding of pAkt and pS6K1 inhibition by Eribulin.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-03-08.

Abstract P6-04-06: Targeting cancer stem cells in triple negative breast cancer by a combination treatment of LBH589 and salinomycin

Background and purpose:

Triple-negative breast cancer (TNBC) is aggressive with poorer prognosis compared to breast cancer that is positive for hormone receptors or HER2. This can be explained further due in part to the existence of breast cancer stem cells (BCSCs). Our lab has found that histone deacetylase (HDAC) inhibitors are effective in the growth suppression of TNBC in vitro and in vivo. To understand the mechanisms involved, we performed RNA-seq analysis for TNBC cells treated with two HDAC inhibitors (LBH589 and Entinostat). Our RNA-seq analysis and studies from other laboratories have found that HDAC inhibitors may modify multiple signaling pathways with undesired effects due to its broad reactivity. To improve the efficacy of HDAC inhibitors in the treatment of TNBCs, we have examined the effects of LBH589 in combination with several drugs. Among them, Salinomycin works effectively with LBH589. It has been used as an antibiotic for farm animals, but has been identified from a screen of a large library of chemicals to target BCSCs (Gupta et al., Cell, 2009). The purpose of this study is to examine the synergistic effect between LBH589 and Salinomycin in the anticipation of their clinical utility and to evaluate a new target therapy to treat TNBC more efficiently and completely.

Material and method:

Two TNBC cell lines (HCC1937, MDA-MB-231) were used as models to examine the combined effects of Salinomycin and LBH589. Cell proliferation studies were performed through 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. To evaluate the effects on BCSC population, mammosphere assay was used for estimating self-renewal capacity and ALDEFLUOR analysis was used for monitoring the distribution of BCSCs in treated samples. For tumor induction experiments, ALDH+ cells were injected into NSG mice. As a therapeutic study, single or combined use of LBH589 (10mg/kg) and Salinomycin (5mg/kg) were peritoneally injected into non-obese diabetic scid gamma (NSG) mice 3 days a week. Tumor volume, body weight and food intake were checked weekly. For mechanistic analysis, qPCR, Western blotting and IHC were performed for gene and protein expression using tumors from mice from different treatments.

Results:

Salinomycin and LBH589 worked synergistically in the suppression of the proliferation of TNBCs (IC50 was 68.8nM and 13.1nM, respectively). Similarly, both drugs inhibited mammosphere formation and ALDH positive population in a synergistic manner. The combination of LBH589 (16nM) with Salinomycin (60nM) reduced 60% of mammosphere formation and 94% of ALDH positive population compared with DMSO treatment. In a mouse model, the combination of LBH589 and Salinomycin had an inhibitory effect on tumor growth compared with the control group and the groups treated with single drug. In all groups, no side effect was seen. The results from mechanistic studies showed that the combination of LBH589 and Salinomycin regulated the Wnt/b-catenin pathway.

Discussion:

We have evidence that the combination of LBH589 and Salinomycin has a synergistic effect on TNBC through Wnt pathway and suggested this combination could potentially be a new therapeutic strategy for exploring targeting therapy in TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-04-06.

Abstract P3-03-07: Combination of eribulin and PI3K inhibitors in triple negative and HER2 expressing breast cancer cell lines results in synergistic growth inhibition and enhanced inhibition of the PI3K pathway

Background. Patients with triple negative breast cancer (TNBC) have high levels of pAkt expression and activation of the PI3K-mTOR pathway. Eribulin is a microtubule-targeting agent with benefits in treating taxane and anthracycline refractory breast cancer. Our objective was to evaluate its efficacy in inhibiting PI3K pathway activity and cell growth both alone and in combination with PI3K/MTOR inhibitors BEZ 235 and BKM 120.

Methods. TNBC cell lines MDA468, BT549, HS587T, MDA231, and HER2 expressing breast cancer cell line SKBR3 were used for this study. Both MDA468 and BT549 have PI3K- related mutations. The tetrazolium salt, 3-4,5 dimethylthiazol-2,5 diphenyl tetrazolium bromide (MTT) assays were used to assess growth inhibition after 72 hour treatment with eribulin, BEZ 235 and BKM 120 both alone and in combination. Combination indices (CI) generated by Chou-Talalay plots were used to quantify synergy. Western blots were used to evaluate the expression of phosphorylated Akt (pAkt), S6K1 (pS6K1) and S6 (pS6) from 30 min to 24 hours of treatment at different doses.

Results. Eribulin has IC50 ranging from 60 pM to 300 pM, BEZ 235 has IC50 ranging from 50 nM to 80 nM, and BKM has IC50 ranging from 500 nM or higher. Standard dilutions of eribulin in combination with BEZ 235 resulted in synergistic growth inhibition (CI<1) in both MDA468 and BT549 cells at all doses tested, but required higher concentrations (500 to 2000 nM) for BKM 120. Western blot analysis for all cell lines treated with eribulin showed pAkt inhibition by eribulin alone with doses as low as 1 nM and as early as 4 hours. PI3K inhibitor alone confirmed inhibition of pAkt, pS6K1 and pS6 at early time points with feedback increase in pAkt at 24h. While both BEZ 235 and BKM 120 treatment increased pAkt in a dose dependent fashion at 24 hours, combination treatment with eribulin showed a dose dependent decrease in pAkt.

Conclusion. Our study shows significant synergistic growth inhibition with the combination of eribulin and PI3K inhibitors. This may be related to inhibition by eribulin of the feedback increase in pAkt seen with PI3K inhibitors alone at later time points. These findings point to a potential role for combination therapy of both eribulin and PI3K inhibitors in treating refractory metastatic disease.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-03-07.

Long-term survival after high-dose chemotherapy followed by peripheral stem cell rescue for high-risk, locally advanced/inflammatory, and metastatic breast cancer

Patients with high-risk locally advanced/inflammatory and oligometastatic (≤3 sites) breast cancer frequently relapse or experience early progression. High-dose chemotherapy combined with peripheral stem cell rescue may prolong progression-free survival/relapse-free survival (PFS/RFS) and overall survival (OS). In this study, patients initiated high-dose chemotherapy with STAMP-V (carboplatin, thiotepa, and cyclophosphamide), ACT (doxorubicin, paclitaxel, and cyclophosphamide), or tandem melphalan and STAMP-V. Eighty-six patients were diagnosed with locally advanced/inflammatory (17 inflammatory) breast cancer, and 12 were diagnosed with oligometastatic breast cancer. Median follow-up was 84 months (range, 6-136 months) for patients with locally advanced cancer and 40 months (range, 24-62 months) for those with metastatic cancer. In the patients with locally advanced cancer, 5-year RFS and OS were 53% (95% CI, 41%-63%) and 71% (95% CI, 60%-80%), respectively, hormone receptors were positive in 74%, and HER2 overexpression was seen in 23%. In multivariate analysis, hormone receptor-positive disease and lower stage were associated with better 5-year RFS (60% for ER [estrogen receptor]/PR [progesterone receptor]-positive versus 30% for ER/PR-negative; P < .01) and OS (83% for ER/PR-positive versus 38% for ER/PR-negative; P < .001). In the patients with metastatic cancer, 3-year PFS and OS were 49% (95% CI, 19%-73%) and 73% (95% CI, 38%-91%), respectively. The favorable long-term RFS/PFS and OS for high-dose chemotherapy with peripheral stem cell rescue in this selected patient population reflect the relative safety of the procedure and warrant validation in defined subgroups through prospective, randomized, multi-institutional trials.

P5-19-05: Age-Related Changes in the Pharmacokinetics (pK), Response, and Toxicity of Weekly nab-Paclitaxel in Patients with Metastatic Breast Cancer (MBC)

Background: Although cancer is a disease of aging, few studies have evaluated the association between patient age and the pK or pharmacodynamics (pD) of cancer therapeutics. The goals of this study were 1) to evaluate the age-related changes in the pK and pD of weekly nab-paclitaxel in patients with MBC; 2) to determine response rate; and 3) to explore the relationship of age with pK and pD parameters (i.e., dose reductions, dose delays and grade ≥ 3 toxicities). Patients and Methods: Forty patients with MBC, receiving 1st or 2nd line chemotherapy, entered an IRB approved protocol to evaluate the age-related changes in the pK of weekly nab-paclitaxel administered at 100 mg/m2 IV for 3 weeks followed by a 1-week break. Patients were accrued from 4 age strata &lt;50, 50–60, 60–70, and &gt;70 years of age. Blood samples were collected for pK analysis with the first dose of nab-paclitaxel. Response was assessed every 2 cycles. Toxicity was graded using the NCI Common Toxicity Criteria for Adverse Events (v 3.0) and was adjudicated as attributable to nab-paclitaxel if it was possibly, probably, or definitely related. Linear regression analysis was used to examine the strength of the relationship between patient age and natural logarithm of 24 hour area under the curve (AUC). Two-sided two-sample t-tests were used to assess if there was a difference in mean age based on the presence of pD variables (i.e., dose reductions, dose delays and grade ≥ 3 toxicities). The significance level was set to 0.05.

Results: Of the 40 patients who entered the study, 39 (98%) were evaluable with a mean age of 60 (SD=13.4; min=30; max=81). Patients were accrued in the following age cohorts: &lt;50 (n= 10; 26%), 50–60 (n= 5; 13%), 60–70 (n= 15; 38%), and &gt;70 (n= 9; 23%) years of age. The median number of courses completed was 4 (min=1, max=21). The response rate was: 0% (n=0) CR, 31% (n=12) PR, 38% (n=15) SD. Grade 3 toxicity was experienced by 26% (n=10). We observed 8% (n=3) grade 3 hematological toxicities [neutrophils (n=1; 3%), leukocytes (n=2; 5%)] and 18% (n=7) grade 3 non-hematological toxicities [nausea and hypophosphatemia (n=1; 3%), diarrhea and infection without neutropenia (n=1; 3%), fatigue (n=2; 5%), hyponatremia (n=1; 3%), and infections without neutropenia (n=2; 5%)]. There were no cases of grade 4 or 5 toxicity. Grade 2 sensory neuropathy was experienced by 8% (n=3; no cases in the 70+ age cohort). Dose reductions or course delays were experienced by 62% (n=24) and 21% (n=8), respectively. There was a borderline significant positive association between age and natural logarithm of total nab-paclitaxel 24 hour AUC (coef=.01; se=.006; p=0.055; n=36). There were no differences in the mean ages based on the presence of grade 3 or higher toxicity (p =0.75), need for dose reductions (p=0.48), or need for dose delays (p=0.61).

Discussion: There is a borderline statistically significant relationship between age and 24 hour AUC but no differences in mean age based on pD variables (i.e., dose reductions, dose delays and grade ≥ 3 toxicities) were identified. The treatment is well-tolerated across all age groups.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-19-05.

A phase I/II prospective, single arm trial of gefitinib, trastuzumab, and docetaxel in patients with stage IV HER-2 positive metastatic breast cancer

Inhibition of the HER-2 pathway via the monoclonal antibody trastuzumab has had a major impact in treatment of HER-2 positive breast cancer, but de novo or acquired resistance may reduce its effectiveness. The known interplay between the epidermal growth factor receptor (EGFR) and HER-2 receptors and pathways creates a rationale for combined anti-EGFR and anti-HER-2 therapy in HER-2 positive metastatic breast cancer (MBC), and toxicities associated with the use of multiple chemotherapeutic agents together with biological therapies may also be reduced. We conducted a prospective, single arm, phase I/II trial to determine the efficacy and toxicity of the combination of trastuzumab with the EGFR inhibitor gefitinib and docetaxel, in patients with HER-2 positive MBC. The maximum tolerated dose (MTD) was determined in the phase I portion. The primary end point of the phase II portion was progression-free survival (PFS). Immunohistochemical analysis of biomarker expression of the PKA-related proteins cAMP response element-binding protein (CREB), phospho-CREB and DARPP-32 (dopamine and cAMP-regulated phosphoprotein of 32 kDa) plus t-DARPP (the truncated isoform of DARPP-32); PTEN; p-p70 S6K; and EGFR was conducted on tissue from metastatic sites. Nine patients were treated in the phase I portion of the study and 22 in the phase II portion. The MTD was gefitinib 250 mg on days 2-14, trastuzumab 6 mg/kg, and docetaxel 60 mg/m(2) every 21 days. For the 29 patients treated at the MTD, median PFS was 12.7 months, with complete and partial response rates of 18 and 46%, and a stable disease rate of 29%. No statistically significant correlation was found between response and expression of any biomarkers. We conclude that the combination of gefitinib, trastuzumab, and docetaxel is feasible and effective. Expression of the biomarkers examined did not predict outcome in this sample of HER-2 overexpressing metastatic breast cancer.

Basal-, Luminal-, and HER2- Molecular Subtype, and the MammaPrint 70-Gene Signature as Predictors of Response to Neoadjuvant Chemotherapy (NCT) with Docetaxel, Doxorubicin, Cyclophosphamide (TAC), or AC and Nab-Paclitaxel and Carboplatin +/- Trastuzumab in Patients (Pts) with Stage II-III and Inflammatory Breast Cancer (BC)

Background: Pathologic complete response (pCR) and minimal residual cancer burden (RCB scores of 0 [pCR]-1[near CR]) after NCT may predict for improved survival (Symmans et al. J Clin Oncol 25:4414-22, 2007). Hence, improved NCT regimens in conjunction with molecular markers that predict for both response and/or resistance are needed. Materials and Methods: 115 pts with stages II-III BC were to be prospectively randomized to receive 6 cycles of docetaxel 75 mg/m2, doxorubicin 50 mg/m2, cyclophosphamide 500 mg/m2 with filgrastim support (TAC, arm A) versus a novel regimen of A 60 mg/m2 and C 600 mg/m2 given every 2 weeks x 4, followed by 3 weekly doses of carboplatin (AUC 2) and nab-paclitaxel 100 mg/m2 repeated as 28 day cycles x 3 (arm B). Pts with HER2 + BC received NCT similar to arm B, but with the addition of 12 weekly doses of trastuzumab given together with carboplatin and nab-paclitaxel (arm C). Core biopsies were performed prior to NCT and were preserved fresh frozen. 70-gene (MammaPrint™) profiling and 80-gene profiling (van de Vijver et al. NEJM 347:1999-2009, 2002) to categorize all tumors for basal-, HER2-, and luminal subtypes were carried out. We set out to assess the predictive value of Mammaprint scores (poor vs. good), as well as basal, vs. luminal, vs. HER2 molecular subtype profiling, for response to treatment on arms A vs. B vs. C. Responses were dichotomized as complete or near complete response (Symmans RCB scores of 0-1) vs. suboptimal response (RCB score &gt; 1). Results: Sufficient amount of BC tissue and good quality RNA for gene array assessment were procured in 64% of the first 90 patients who have undergone pre-treatment core biopsies, and then proceeded to NCT, followed by definitive surgery. Here we report on the first 50 pts with complete set of data analyzed. The median age was 50 years (range:31-69). Pts were treated for stage II (49%) and III locally advanced (41%), and inflammatory BC (10%). By gene profiling, 28% of the tumors were HER2-type (vs. 38% by IHC 3+, or FISH, representing all pts treated on arm C), 26% basal-type, 42% luminal-type, and 4% borderline luminal-type. Poor-prognosis signature by the 70-gene (MammaPrint) assay was observed in 74% of pts: 92% of HER2-type, 100% of basal-type, and 52% of luminal-type tumors were characterized as poor-risk by the 70-gene assay. Following NCT, Symmans RCB scores of 0-1 were observed in 71% of pts with HER2-type, in 38% with basal-type, and 28% of pts with luminal-type molecular subtype characteristics. Conclusion: BC with HER2- and basal-molecular subtypes are more likely to respond to NCT and is frequently associated with poor-risk characteristics as determined by the 70-gene assay. The complete analysis of correlations among response to specific sets of NCT, molecular subtype, and 70-gene assay results in the entire pt population will be presented.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2026.

Barriers to Treatment in Patients with Locally Advanced and Inflammatory Breast Cancer

Background: Breast cancer in the United States will affect approximately one in eight women. Despite a decrease in breast cancer mortality due to increased awareness and more effective screening, many patients still present for treatment after extended delays in diagnosis, resulting in large tumor size, locally advanced disease, inflammatory features, and greater likelihood of regional and distant metastasis. The purpose of this study was to identify reasons why patients may encounter delays in obtaining a diagnosis, seeking medical care, and initiating treatment once symptoms appear.Methods: From 12/2006 through 5/2009, a questionnaire was administered to thirty-four consecutive patients who presented to our institution with histologically-verified stage III breast cancer who had experienced a 3-month or greater delay in diagnosis and initiation of treatment from time of onset of symptoms. The 39-item Likert-scale questionnaire was developed to explore perceived barriers. Responses were rated on a scale of "Strongly Agree" through "Strongly Disagree," relative to the barriers presented.Results: The median age of patients who completed the questionnaire was 52 years (range, 30 to 78 years). Of these, there were 29.4% White/Non-Hispanic, 52.9% White/Hispanic, 11.8% Black and 5.9% Asians. For 73.5% of patients, the diagnosis of breast cancer was made at an outside institution. Most of the participants were diagnosed with locally advanced infiltrating ductal carcinoma (82.4%) and 8.8% were diagnosed with inflammatory breast cancer. Barriers to treatment were divided into the following categories:Patient barriers: The most commonly reported barrier among respondants was "waiting for the scheduled visit to get results." (47.1% with a response of Agree or Strongly Agree) However, 35.2% of patients did not seek treatment because they were concerned about losing their breast. More than a third of patients delayed care because of perception that their breast symptoms were due to infection, muscle strain, or related to their menstrual cycle (35.3%). For 27.6% of respondants, no care was sought because of perception that their breast symptoms would resolve with time. Other barriers, such as access to transportation,, inconvenient physician office hours, child care problems and inability to take time off from work, continued to be present but were not as frequently reported (less than 20%).Physician barriers: Approximately one fourth of women reported that their physician of initial contact, did not believe that their breast lump/symptom was related to cancer (23.5%).System barriers: Among systems barriers, "delay in scheduling diagnostic tests" remained the most prevalent barrier to breast cancer treatment (38.2%).Conclusion: We observed substantial delays between symptom presentation and diagnosis in patients who came to seek therapy at a tertiary comprehensive cancer center (City Of Hope National Medical Center) in Southern California. Patients and physicians need to be educated on the importance of timely diagnostic tests and follow-up visits. In addition, studies are needed to better identify predictive factors for women at risk for encountering barriers to healthcare so that for these subpopulations, interventions can be implemented to reduce breast cancer morbidity and mortality.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3084.

Quality-of-life and LhRH agonist therapy among prostate cancer patients following PSA failure

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Background: Growing numbers of prostate cancer patients experience biochemical relapse (PSA failure) after initial treatment. LhRH agonist (hormonal) therapy can reduce PSA levels, but there is no clear evidence that it slows disease progression or reduces mortality. Quality of Life (QoL) issues are essential when deciding between observation (OBS) versus hormonal castration following biochemical relapse. We evaluated health related quality of life and treatment satisfaction among prostate cancer patients who experience PSA failure. Methods: Eligibility criteria were receipt of primary therapy for prostate cancer followed by a PSA nadir and subsequent PSA rise to at least 0.2 ng/ml. Data sources include medical records and interviewer administered surveys on health- related QoL at baseline, 3 and 12 months. Results: Castrated versus observed patients who are satisfied with their sexual activity report similar health-related QoL, with the exception of higher rates of maintaining an erection (73.3% vs. 32.0%) and not having prostate cancer affect sexual activity (66.7% vs. 28.6%). Castrated and expectant management patients with low levels of satisfaction and sexual activity report similar health-related QoL. Conclusions: Among patients with PSA Failure, the only health-related QOL difference is reflected in sexual activity related to erectile dysfunction, but not sexual satisfaction among patients who all have a high level of treatment decision satisfaction and sexual activity. [Table: see text]

[Table: see text]

Comparability of health-related quality of life (HRQOL), treatment decision making, and treatment satisfaction after PSA recurrence among prostate cancer patients who receive hormone therapy (HT) versus observation (OBS): Results from the COMPARE registry

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Background: HT may lower PSA, but it may also cause hot flashes and sexual dysfunction. OBS is not associated with hot flashes or lower testosterone production, but PSA may rise. Examining patient satisfaction with treatment decision making, treatment choice, and HRQOL may help improve disease management. We compared treatment satisfaction and HRQOL of patients who chose OBS over HT. Methods: The Comprehensive Multicenter Prostate Adenocarcinoma Registry (COMPARE) is an observational registry of men with PSA failure. Data from patient-reported questionnaires were analyzed for patients treated with OBS or HT. Results: 674 patients (82%) chose OBS; 147 (18%) chose HT. The median time between cancer diagnosis and registry enrollment was 6 years. Of men on OBS, 85%, 83%, and 71% were satisfied with treatment decision process, treatment choice, and treatment outcome, respectively. Men on HT had similar rates of satisfaction (82%, 75%, and 71%). Men initially treated with brachytherapy/surgery were less satisfied with OBS. Men initially treated with external beam radiation were less satisfied with HT. Patients reported similar problems with urinary, sexual, and bowel function. Conclusions: Men with PSA failure seem content with treatment choice and decision making and have low rates of urinary/bowel problems. Rates of sexual dysfunction in both groups are similar. Clinical trials may help determine if HT improves long-term outcomes (e.g. overall survival), since short-term patient reported satisfaction is similar between OBS and HT. The reported rate of sexual dysfunction is lower than expected.

[Table: see text]

[Table: see text]

The combination of the HER2 antibody trastuzumab, the EGFR tyrosine kinase inhibitor gefitinib, and docetaxel as first-line therapy in patients with HER2 overexpressing stage IV breast carcinoma

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Background: Interference with both HER2 and epidermal growth factor (EGFR) dependent pathways may improve therapeutic efficacy of docetaxel (doc) in pts with HER2 overexpressing (+) BC. Methods: Patients (pts) without prior chemotherapy (Rx) exposure for stage IV HER-2 + BC were enrolled. Prior hormonal or adjuvant Rx inclusive of taxane or trastuzumab (tras) were allowed. A left ventricular ejection fraction of > 45% and ECOG performance status of ≥ 2 were required. Pts were to receive doc 75 m2, tras every 3 weeks, and gefitinib (gef) 250 mg daily. BC samples from 12 pts were analyzed by FISH for HER2 and EGFR amplification (amp), and topoisomerase II (topo II) amp or loss. IHC was to be performed to examine p-Src, p-STAT3, Ki67 and survivin expression. Results: The median age was 49 (range, 34–67) and ECOG performance status 0.5 (0–1). The first 9 patients received gef 250 mg daily; 2 pts received dox 75 mg/m2 and developed grade 3 febrile neutropenia (neu), hence, additional pts received doc at 60 mg/m2: 3 more episodes of grade 3 neu were seen. Gef was held due to grade 3 dermatitis (2 pts) and diarrhea (2 pts). Pts received a median of 6 cycles (3–10). Gef schedule then was changed, and was prescribed on days 2–14, only. Three of the next 9 pts experienced grades 3 or 4 neu, and we observed 3 cases of grade 3 gastrointestinal toxicities; pts were able to receive 11 + (range; 5–25+) cycles on this schedule (p<0.04). There were 4 complete (CR)and 6 partial R (23 % CR, 59 % overall R), and 3 pts had stable disease (SD; all R and SD confirmed); 3 pts progressed at 4, 4, and 5 mos, 1 pt was inevaluable. The median time to progression is 12 + mos. Samples from 3 pts revealed topo II amplification and one pt sample showed loss of one topo II allele; none were amplified for EGFR. Outcome will be correlated with IHC defined signal trasduction status and proliferation rates. Conclusions: The combination of doc, tras, and short course of gef is feasible, with encouraging R and SD rates and time to progression. Further exploration of simultaneous blockage of multiple signal transduction pathways is indicated in combination with chemoRx. Supported by NCI CA33572 and by a grant from AstraZeneca.

No significant financial relationships to disclose.

Three-fermion problems in optical lattices

We present exact results for the spectra of three fermionic atoms in a single well of an optical lattice. For the three lowest hyperfine states of 6Li atoms, we find a Borromean state across the region of the distinct pairwise Feshbach resonances. For 40K atoms, nearby Feshbach resonances are known for two of the pairs, and a bound three-body state develops towards the positive scattering-length side. In addition, we study the sensitivity of our results to atomic details. The predicted few-body phenomena can be realized in optical lattices in the limit of low tunneling.

A Role for the 2′ Residue in the Second Transmembrane Helix of the GABAA Receptor γ2S Subunit in Channel Conductance and Gating

GABA(A) receptors composed of alpha, beta and gamma subunits display a significantly higher single-channel conductance than receptors comprised of only alpha and beta subunits. The pore of GABA(A) receptors is lined by the second transmembrane region from each of its five subunits and includes conserved threonines at the 6', 10' and 13' positions. At the 2' position, however, a polar residue is present in the gamma subunit but not the alpha or beta subunits. As residues at the 2', 6' and 10' positions are exposed in the open channel and as such polar channel-lining residues may interact with permeant ions by substituting for water interactions, we compared both the single-channel conductance and the kinetic properties of wild-type alpha1beta1 and alpha1beta1gamma2S receptors with two mutant receptors, alphabetagamma(S2'A) and alphabetagamma(S2'V). We found that the single-channel conductance of both mutant alphabetagamma receptors was significantly decreased with respect to wild-type alphabetagamma, with the presence of the larger valine side chain having the greatest effect. However, the conductance of the mutant alphabetagamma receptors remained larger than wild-type alphabeta channels. This reduction in the conductance of mutant alphabetagamma receptors was observed at depolarized potentials only (E(Cl) = -1.8 mV), which revealed an asymmetry in the ion conduction pathway mediated by the gamma2' residue. The substitutions at the gamma2' serine residue also altered the gating properties of the channel in addition to the effects on the conductance with the open probability of the mutant channels being decreased while the mean open time increased. The data presented in this study show that residues at the 2' position in M2 of the gamma subunit affects both single-channel conductance and receptor kinetics.

Perturbative effective theory in an oscillator basis?

The effective interaction problem in nuclear physics is believed to be highly nonperturbative, requiring extended high-momentum spaces for accurate solution. We trace this to difficulties that arise at both short and long distances when the included space is defined in terms of a basis of harmonic oscillator Slater determinants. We show, in the simplest case of the deuteron, that both difficulties can be circumvented, yielding highly perturbative results in the potential even for modest (approximately 4 variant Planck's over 2pi omega) included spaces.

Protection of Aotus monkeys by Plasmodium falciparum EBA-175 region II DNA prime-protein boost immunization regimen

Aotus monkeys received 4 doses of Plasmodium falciparum EBA-175 region II vaccine as plasmid DNA (Dv-Dv) or recombinant protein in adjuvant (Pv-Pv) or as 3 doses of DNA and 1 dose of protein (Dv-Pv). After 3 doses, antibody titers were approximately 10(4) in DNA-immunized monkeys and 10(6) in protein-immunized monkeys. A fourth dose did not significantly boost antibody responses in the Dv-Dv only or Pv-Pv only groups, but titers were boosted to approximately 10(6) in monkeys in the Dv-Pv group. Four weeks after the last immunization, the animals were challenged with 10(4) P. falciparum-parasitized erythrocytes. Peak levels of parasitemia were lower in the 16 monkeys that received region II-containing plasmids or proteins than in the 16 controls (geometric mean: 194,178 and 410,110 parasites/microL, respectively; P=.013, Student's t test). Three of 4 monkeys in the Dv-Pv group did not require treatment. These data demonstrate that immunization with EBA-175 region II induces a significant antiparasite effect in vivo.

A recombinant baculovirus-expressed Plasmodium falciparum receptor-binding domain of erythrocyte binding protein EBA-175 biologically mimics native protein

EBA-175 of Plasmodium falciparum is a merozoite ligand that binds its receptor glycophorin A on erythrocytes during invasion. The ligand-receptor interaction is dependent on sialic acids as well as the protein backbone of glycophorin A. Region II (RII) of EBA-175 has been defined as the receptor-binding domain. RII is divided into regions F1 and F2, which contain duplicated cysteine motifs. We expressed RII in a baculovirus and show that RII binds erythrocytes with a specificity identical to that of the native protein. We found that, consistent with the binding of erythrocytes to COS cells expressing F2, recombinant baculovirus-expressed F2 bound erythrocytes. About 20% of all baculovirus-expressed RII is N-glycosylated, unlike native P. falciparum proteins that remain essentially unglycosylated. However, glycosylation of recombinant RII did not affect its immunogenicity. Antibodies raised against both glycosylated and unglycosylated baculovirus-expressed RII recognized P. falciparum schizonts in immunofluorescence assays and also gave similar enzyme-linked immunosorbent assay titers. Furthermore, these antibodies have similar abilities to block native EBA-175 binding to erythrocytes. These results allow the development of RII as a vaccine candidate for preclinical assessment.

Biochemical markers of acute myocardial infarction: strategies for improving their clinical usefulness

We investigated the early diagnostic utility, including incremental value, of the serum cardiac markers creatine kinase (CK), CK-MB (mass and activity measurements), cardiac troponin T, and myoglobin in the diagnosis of acute myocardial infarction (AMI) in patients presenting to a major teaching hospital with chest pain and non-diagnostic electrocardiographs (ECG). The reference diagnosis of acute myocardial infarction was made by a single, independent cardiologist using World Health Organization criteria. CK and CK-MB mass were the only significant predictors of AMI at presentation to the Emergency Department. Logistic regression analysis revealed that CK did not significantly predict (P = 0.23) myocardial infarction once CK-MB mass was in the model. Using test results on follow up, in addition to presentation CK-MB mass, change in CK-MB mass was the only other significant independent predictor of AMI. Likelihood ratios for various levels of the significant markers in the logistic regression are given. In conclusion, CK-MB mass measurement was the only useful serum cardiac marker for the diagnosis of AMI in patients presenting with chest pain with non-diagnostic ECGs.

Automated multiple peptide synthesis: improvements in obtaining quality peptides

Production of multiple overlapping peptides is a key step in the identification of T-cell epitopes. A large number of peptides can be produced by using ABIMED's automated multiple peptide synthesizer. We report here considerable improvement in the software and chemistry of peptide synthesis by introducing a resin mixing step during coupling, when using this synthesizer. A comparison of two solvent systems for synthesis was performed. Six test peptides were synthesized by standard and modified methods. The purity of peptides, assessed by HPLC and mass spectrometry, showed a substantial improvement when automated resin mixing and mixed solvent system were used. These improvements enable us to produce 48 peptides within a week each of sufficient purity to be used for rapid screening of T-cell epitopes.

Decreased skin blood flow early in the course of streptozotocin-induced diabetes mellitus in the rat

We have previously used laser Doppler technology to demonstrate that skin blood flow is reduced in Type 1 (insulin-dependent) diabetic patients. The possibility of using the skin as an extremely accessible indicator of diabetic microvascular disease is attractive. The streptozotocin diabetic rat is an appealing potential animal model. We performed measurements of skin blood flow in two rat species, nine Sprague Dawley (SD) rats and nine Wistar Kyoto (WKY) rats, observing early changes following the inception of diabetes. Four of the SD rats and five of the WKY rats were made diabetic, the rest serving as controls. There were no significant differences in skin blood flow between the two rat strains. As in man, there appear to be rat skin sites with primarily nutritive capillary supply and those with arteriovenous anastomotic predominance. The back and base of tail, both hair-covered areas, demonstrated low flow characteristics, consistent with nutritive perfusion. In contrast, the plantar surface of the paw behaved similarly to the finger or toe pulps in man, sites of arteriovenous perfusion, with high basal flow and a marked increment with thermal stimulation. In diabetic rats of both species, there was significantly lower flow at the back and base of tail than in non-diabetic animals. The differences were of the order of 30-40%. As a function of time, the decrease in blood flow at the base of tail parallelled the increase in glycohaemoglobin levels in the diabetic rats. In contrast, blood flow at the plantar surface of the paw was unchanged throughout the 3-month post-streptozotocin observation period.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of increasing temperature on skin blood flow and red cell deformability

Using laser Doppler techniques in nine healthy volunteers, we contrasted the effect of increasing local skin temperature at the elbow, a skin site with nutritive microvasculature, and the finger pulp, with predominantly arteriovenous anastomic (AVA) perfusion). We also assessed flow at the finger dorsum, with contributions of both types of microvasculature. In parallel with the laser Doppler studies, we determined the effect of increasing temperature on the red cell deformability of our subjects, using the new technique of Cell Transit Time Analysis (CTTA). Thermal stimulation produced very large increases in skin blood flow at all three sites tested. However, the magnitude and the pattern of increase were different at the three sites. At the finger pulp, there was a linear approximately threefold increase in flow as temperature increased from the basal level to 44 degrees C. At the elbow, basal flow was considerably lower than at the finger pulp and increased very slowly until skin temperature reached 38 degrees C. From that point, flow increased sharply, reaching tenfold the basal level at 44 degrees C. The thermally induced increase at the finger dorsum was intermediate between the other two sites, with a pattern resembling the elbow more than the finger pulp. These differences among the sites were attributable to substantially different patterns of change in the two components of flow, microvascular volume and velocity. At the finger pulp, there was very little increase in microvascular volume with increasing temperature. The curve was practically flat from basal temperature to 44 degrees C. In contrast, there was a linear increase in red blood cell velocity of about 300%. At the elbow, both microvascular volume and red blood cell velocity exhibited a parallel curvilinear pattern of equivalent increase, on the order of 300% for each. There was only a small increase in both parameters until the temperature reached 38 degrees, at which point there was a sharp increase in both. At the finger dorsum, the situation was intermediate, again resembling the elbow more than the finger pulp. Cell Transit Time Analysis revealed a progressive decrease in red cell transit time (TT), from 3.28 ms at 28 degrees C to 2.48 m at 44 degrees C, an overall change of 24%. The decrease in TT was accompanied by an increase in transit frequency, measured as counts s-1 (C s-1), from 3.1 to 5.3, an overall change of 71%. The changes in both TT and C/S were essentially linear.(ABSTRACT TRUNCATED AT 400 WORDS)

Red cell filterability determined using the cell transit time analyzer (CTTA): effects of ATP depletion and changes in calcium concentration

Cell transit time analysis (CTTA) is a new filtrometric technique for assessing red blood cell deformability by measuring the conductivity change caused by passage of erythrocytes through a polycarbonate filter. Most reported studies to date using CTTA have focused on the transit time (TT), the duration of passage of an individual red cell through a micropore. Bulk flow rate has not been previously measured via CTTA. The use of new enzyme based cleaning solutions make it possible to reduce clogging in micropore filters. Therefore, valid measures of the number of red cell transits per unit time (counts/s: C/S) can now be obtained. We evaluated both parameters, TT and C/S, as indicators of red cell filterability. Our goal was to evaluate the effect of metabolic changes shown by alternative techniques to affect red cell deformability. The two best established factors are changes in intracellular [ATP] and [Ca2+]. ATP depletion produces a very small increase in TT but a very marked decrease in C/S. In contrast, the addition of low concentrations of calcium produces an increase in TT with minimal decrease in C/S. The effects of calcium appear to be complex. The substantial changes in intracellular calcium induced by the ionophore A23187 result in a curvilinear pattern of increase in transit times and reduction in counts per s. Lanthanum, which inhibits egress of intracellular calcium, causes an increase in TT with a drop in C/S. We conclude that CTTA demonstrates the same changes in red cell deformability measurable by alternative filtrometric techniques; however, CTTA furnishes two separate and independent parameters which may be used to evaluate red cell deformability.

Effect of standard doses of epinephrine on myocardial oxygen delivery and utilization during cardiopulmonary resuscitation

This preliminary study was conducted to evaluate the effects of 0.02 mg/kg of epinephrine (E) on myocardial blood flow (MBF), myocardial oxygen consumption (MVO2), and delivery (MDO2) when administered during CPR after 10-min cardiopulmonary arrest. Five miniature swine were instrumented for MBF measurements using tracer microspheres. Ventricular fibrillation was induced. After 10 min, CPR was begun with a pneumatic compressor. Measurements of MBF, arterial, and coronary sinus blood gases were made. After 3 min of CPR, each animal received 0.02 mg/kg of E. The measurements were repeated and defibrillation was attempted. During CPR, MDO2 and MVO2 were 0.2 +/- 0.3 and 0.2 +/- 0.3 ml/min/100 g tissue, respectively. The myocardial oxygen extraction ratio (ER) was 94.2 +/- 3.0%. After 0.02 mg/kg of E, MDO2 was 1.1 +/- 1.4, MVO2 was 1.0 +/- 1.3, and ER was 93.9 +/- 0.7% (p greater than .05). There were no successful defibrillations. These data indicate that MDO2 improves slightly during CPR after 0.02 mg/kg of E, but it does not meet the oxygen demands of the fibrillating heart.

Myocardial oxygen delivery/consumption during cardiopulmonary resuscitation: a comparison of epinephrine and phenylephrine

Our study compared the effect of high-dose epinephrine with the pure alpha-agonist phenylephrine on regional myocardial blood flow (MBF), myocardial oxygen delivery (MDO2), myocardial oxygen consumption (MVO2), and defibrillation rates during CPR. Fifteen swine weighing more than 15 kg were instrumented for measurement of regional MBF using radiolabeled tracer microspheres. Measurements of regional MBF, MDO2, and MVO2 were made during normal sinus rhythm. Ventricular fibrillation was induced and persisted for ten minutes. CPR was begun using a pneumatic compression device. Regional MBF, MDO2, and MVO2 were measured during CPR. Following three minutes of CPR, animals (N = 15) were allocated to one of three groups (n = 5): Group 1, epinephrine 0.2 mg/kg; Group 2, phenylephrine 0.1 mg/kg; or Group 3, phenylephrine 1.0 mg/kg. Measurements of regional MBF, MDO2, and MVO2 were repeated after drug administration. Extraction ratios, defined as MVO2/MDO2, were calculated during normal sinus rhythm, CPR, and after drug administration. Defibrillation was attempted 3 1/2 minutes after drug administration. There was no significant difference in MBF, MDO2, MVO2, and extraction ratio during normal sinus rhythm and CPR for any of the groups. Total MBF following drug administration was 67.2 +/- 49.4 mL/min/100 g for the group receiving epinephrine 0.2 mg/kg; 7.0 +/- 7.1 mL/min/100 g for the group receiving phenylephrine 0.1 mg/kg; and 36.7 +/- 21.1 mL/min/100 g for the group receiving phenylephrine 1.0 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of epinephrine versus methoxamine on regional myocardial blood flow and defibrillation rates following a prolonged cardiorespiratory arrest in a swine model

Recent studies in swine have shown that larger doses of epinephrine than those currently employed for cardiopulmonary resuscitation (CPR) significantly improve regional myocardial blood flow following prolonged cardiac arrest. The dose-response effect of a pure alpha-adrenergic agonist, methoxamine, on regional myocardial blood flow has not been investigated in this setting. This study compared the effect of high-dose epinephrine with graded doses of methoxamine on regional myocardial blood flow, oxygen delivery/utilization, and defibrillation rates during CPR. Twenty swine were instrumented for regional myocardial blood flow measurements using radiolabeled tracer microspheres. Measurements of regional myocardial blood flow, oxygen delivery, and oxygen consumption were made during normal sinus rhythm. Ventricular fibrillation was then induced. Following 10 minutes of ventricular fibrillation, CPR was initiated with a pneumatic compressor. Regional myocardial blood flow, oxygen delivery, and oxygen consumption were then measured during CPR. Following 3 minutes of CPR, the swine were allocated to one of four treatment groups (five per group): group I, epinephrine 0.2 mg/kg; group II, methoxamine 0.1 mg/kg; group III, methoxamine 1.0 mg/kg; and group IV, methoxamine 10.0 mg/kg. One minute after drug administration, regional myocardial blood flow, oxygen delivery, and oxygen consumption measurements again were made. Three and one half minutes after drug administration, defibrillation was attempted. Regional myocardial blood flow following drug administration was compared using an analysis of covariance. Epinephrine (0.2 mg/kg) significantly improved myocardial blood flow (P less than .002) for all tissues examined compared with all doses of methoxamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance measurement techniques for simple Fourier transform lenses

The use of simple off-the-shelf lenses as Fourier transform elements in an optical computer is considered. Several schemes for measuring those lens parameters that determine the performance of such simple lenses as Fourier transform elements are provided with emphasis on lens phase errors. It is assumed that no lens design data are available for the lens under test.