Abstract P6-17-15: Evaluating preclinical efficacy of anti-HER2 drug combinations using ER+/HER2 mutant models

Background

Until recently, HER2 gene amplification was the only mechanism of HER2 activation recognized. However, activating HER2 mutations have been noted in different cancer types. A trials of HER2 mutant breast cancer and the subsequent SUMMIT trial data have shown that monotherapy with the pan-HER drug neratinib as showed clinical efficacy, but with poor response durability. This study therefore investigates the preclinical efficacy of anti HER2 agents alone or in combination with endocrine therapy agents or in combination with CDK4/6 inhibitors using ER+/HER2 mutant cell lines and ex vivo HER2 mutant patient derived xenograft (PDX) model to define a more effective treatment approach.

Methods

ER+ breast cancer cell lines (T47D and MCF7) stably expressing HER2V777L, and ER+/HER2 mutant PDX model (HER2G778_P780 dup) were used to examine HER2 signaling and drug responses. Signaling downstream mutant HER2 was examined by immunoblot analysis. Effects of neratinib alone, neratinib + fulvestrant, and neratinib + abemaciclib on cell growth were examined in ER+/HER2 mutant cell lines and in an ex vivo HER2G778_P780 dup.

Results

We found that MCF7/T47D cells expressing HER2V777L and HER2G778_P780 dup PDX tumors showed strongly activated autophosphorylation of HER2 and increased expression of CDK4, CDK6, phospho-Rb, and cyclin D1 as compared to MCF7/T47D cells expressing HER2WT or ER+/non-HER2mut PDX modes, suggesting that HER2 mutations preferentially depend on CDK4/6 signaling for cell growth. Additionally, we showed that activating MCF7 HER2 V777L cause resistance to endocrine therapy treatment (fulvestrant IC50 >5μM). Further, we show that neratinib alone is effective at higher concentrations (IC50 < 2μM) in MCF7/HER2 V777L cells. We also demonstrate that abemaciclib alone exhibited moderate activity against MCF7 HER2 V777L cells (IC50 < 0.4μM) and additional activity in combination with neratinib (IC50 < 0.06μM) was seen. Moreover, ex vivo HER2 G778_P780 dup cells are relatively resistant to fulvestrant alone (IC50 < 0.2μM), neratinib alone (IC50 < 0.006μM), abemaciclib alone (IC50 < 0.04μM), and neratinib in combination with abemaciclib (IC50 < 0.005μM), suggesting that patients harboring ER+/HER2-mutant tumors may benefit from neratinib in combination with abemaciclib.

Conclusion

These preclinical data suggest that neratinib monotherapy may not be effective to treat ER+/HER2 mutant patients and we propose that simultaneous targeting of both HER2 and the CDK4/6 axis will be required for effective treatment of ER+ breast cancers harboring HER2 activating mutations.

Citation Format: Kavuri SM, Devarakonda V, Williams LC, Seker S, Lei JT, Singh P, Han A, Anurag M, Holloway KR, Welm AL, Ellis MJ. Evaluating preclinical efficacy of anti-HER2 drug combinations using ER+/HER2 mutant models [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-15.

Abstract P5-04-30: Developing an immunohistochemistry protocol to detect neurofibromin as an effective, simple, and rapid method to identify NF1-negative breast cancer patients

Background:Neurofibromin is a key tumor suppressor, well-known as a GTPase-Activating-Protein (GAP) to attenuate Ras signaling. It is encoded by the NF1gene, so named because its inactivation was first discovered to cause Neurofibromatosis type 1, an autosomal dominant genetic disorder. We have recently reported thatnonsense (NS) and frameshift (FS) mutations, but not missense mutations, in NF1are associated with a markedly higher risk of relapse and death in early stage ER+breast cancer after adjuvant tamoxifen monotherapy (Griffith et al. in press). Surprisingly, despite being best known as a GAP, no missense mutations inactivating NF1's GAP activity were found in our cohort. We have evidence that these NF1NS/FS mutations cause the resulting mRNAs to be degraded, leading to depletion of the entire NF1 protein. In a separate study that was presented here last year, we showed that NF1 is also an ER co-repressor, which partially explains why the loss of the single tumor suppressor NF1 is so detrimental — because this turns on two potent oncogenic pathways. Thus far there is no effective means to assess loss of NF1 protein in cancer. The objective of this project is to identify these aggressive NF1-negative breast cancers by establishing an immunohistochemistry (IHC) protocol with a valid NF1 antibody in order to properly find and treat them in the future.

Methods:A monoclonal antibody was raised against the C-terminus of NF1. Immunostaining as well as IHC was performed using a set of breast cancer cell lines with varying degrees of NF1 protein levels, including several NF1 null-like cell lines as negative controls. To assess whether the IHC protocol can be used on patients, NF1+and NF1–PDXs as well as patient biopsies were examined.

Results: We have purified a monoclonal antibody against NF1 (m376). By immunostaining, a strong NF1 signal can be seen in T47D cells, which have four copies of the NF1gene. In contrast, there was barely any signal in MDA-MB-175VII cells, which lack detectable NF1 due to NF1FS mutations. While NF1 appears mostly cytoplasmic, 10-15% can be seen in the nucleus. Nuclear NF1 levels can be further increased by the nuclear export blocker leptomycin-B, suggesting that NF1 is shuttled in and out of the nucleus. IHC staining confirmed these features of NF1. In addition, a weak nuclear signal can be seen in cancer cells carrying NF1FS mutations. Experiments are on-going to assess how to analyze tumor samples for NF1 loss and whether NF1FS mutations cause expression of truncated proteins that are nuclear.

Conclusion: Our results suggest that the m376 antibody has the potential to be used for IHC, provided that samples known to be NF1+or NF1–are included as controls. The success of this project will have particular clinical impact in telling us who should notbe treated by tamoxifen. Furthermore, we have an approved clinical trial protocol to assess the concept that these NF1–patients should instead be treated by combining a Ras pathway inhibitor and a SERD.

Citation Format: Peng J, Zheng Z-y, Cakar B, Li J, Singh P, Szafrain AT, Stossi F, Dubrulle J, Mancini MA, Mao R, Miles G, Ellis MJ, Chang EC. Developing an immunohistochemistry protocol to detect neurofibromin as an effective, simple, and rapid method to identify NF1-negative breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-04-30.

Abstract P5-08-01: DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer

Proteogenomics is the field of integrating data from mass spectrometry-based shotgun proteomics, and phosphoproteomics into next-generation RNA and DNA sequencing data analysis pipelines that promises new insights into cancer biology and therapeutic targeting. As well as analyses of clinical samples for disease phenotype association analysis, the application of proteogenomics to model systems also has considerable potential. A Clinical Proteomic Tumor Analysis Consortium (CPTAC) proteogenomic analysis prioritized dihydropyrimidinase-like-3 (DPYSL3) as a multi-level (RNA/Protein/Phosphoprotein) expression outlier specific to the Claudin-Low (CLOW) subset of triple negative breast cancers. A Pubmed informatics tool indicated a paucity of data in the context of breast cancer which further prioritized DPYSL3 for study.

DPYSL3 was identified as a protein that is regulated during neuronal differentiation in the cerebral cortex and in neuronal cell lines and plays a role in regulating neurite outgrowth somehow through an association with vesicles in the growth cone. In addition, DPYSL3 expression has been observed in several malignant tumors, including prostate cancer, pancreatic cancer, gastric cancer and neuroblastoma. DPYSL3 is reported to play a role in cell migration and metastasis suppression in prostate cancer. However, in pancreatic cancer, DPYSL3 is positively associated with liver metastasis and poor outcome.

DPYSL3 knock-down in DPYSL3 (+) CLOW cell lines demonstrated reduced proliferation, yet enhanced motility and increased expression of Epithelial to Mesenchymal Transition (EMT) markers suggesting that DPYSL3 is a multi-functional signaling modulator. Slower proliferation in DPYSL3 (-) CLOW cells was associated with accumulation of multi-nucleated cells indicating a mitotic defect that was associated with a collapse of the vimentin (VIM) microfilament networkinduced by VIM hyperphosphorylation. On the other hand, DPYSL3 suppressed the expression of EMT regulators TWIST and SNAIL and opposed p21 activated kinase 2 (PAK2) dependent migration, but these EMT regulators in turn induced DPYSL3 expression, suggesting DPYSL3 participates in negative feedback in EMT. Cell migration in DPYSL3 (-) cells correlated with increased phosphorylation of PAK2 on Ser20 and was sensitive to PAK2 siRNA and pharmacological PAK inhibition.Immunoprecipitation and mass spectrometry-based proteomics or western blotting strongly suggests that PAKs interact such that DPYSL3 may function as a direct negative regulator of PAK family kinases. Thus, a PAK inhibitor could potentially mitigate increase migration as an adverse effect of DPYSL3 suppression.

In conclusion, DPYSL3 is a remarkable multifunctional signaling scaffold that should be examined further to provide insights into the stem cell-like state of claudin-low breast cancers, particularly in terms of their cell cycle dependencies, migratory activity and capacity for EMT.

Citation Format: Matsunuma R, Chan DW, Kim B-J, Singh P, Han A, Saltzman A, Cheng C, Lei JT, Sahin E, Leng M, Fan C, Perou CM, Malovannaya A, Ellis MJ. DPYSL3 modulates mitosis, migration and epithelial to mesenchymal transition in claudin-low breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-08-01.

Low energy electron and positron impact differential cross sections for the ionization of water molecules in the coplanar and perpendicular kinematics

We report here triply differential cross sections (TDCSs) for 81 eV electron and positron-impact ionization of the combined (1b₁ + 3a₁) orbitals of the water molecule by using the second-order distorted wave Born approximation (DWBA2) for ejection electron and positron energies of 5 eV and 10 eV and different momentum transfer conditions. The electron-impact TDCS will be compared with the experimental data measured by Ren et al. [Phys. Rev. A 95, 022701 (2017)] and with the molecular 3-body distorted wave (M3DW) approximation results in the scattering plane as well as the perpendicular plane. The DWBA2 results are in better agreement with the experiment than the M3DW results for the scattering plane, and the M3DW results are somewhat better for the perpendicular plane. This observation is explained in terms of collision interactions. The electron and positron TDCSs are indistinguishable in the scattering plane. In the perpendicular plane, the positron results are similar in shape, but smaller in magnitude. However, the difference reduces with increasing projectile scattering angle and increasing ejected electron energy.

Idiopathic Bilateral Optic Neuritis

Idiopathic bilateral optic neuritis in adult has been reported very rarely. The objective of this report is to present a case of idiopathic bilateral optic neuritis in adult and treatment responses. A nineteen year old female presented with bilateral optic neuritis. It was characterized by decreased visual acuity, painful ocular motility and sluggish pupillary reaction with Relative Afferent Pupillary Defect (RAPD) in left eye, hyperemic and generalized optic disc swelling and central scotoma in Humphrey visual field of both eyes. MRI showed diffuse thickening and irregularly outlined optic nerves of both eyes. Idiopathic bilateral optic neuritis in adults is a rare presentation. Prompt treatment with optic neuritis treatment trial (ONTT) improved the visual outcome.

The efficacy and safety outcomes of the 0.19 mg fluocinolone acetonide implant after prior treatment with the 0.7 mg dexamethasone implant in patients with diabetic macular edema

Purpose

There are little or no published data comparing the outcomes of ILUVIEN^® (0.19 mg fluocinolone acetonide [FAc]) and OZURDEX^® (0.7 mg dexamethasone [DEX]) implants in patients with diabetic macular edema (DME), and this case sought to compare their outcomes.

Methods

This case was extracted from a monocentric audit involving a pool of 25 patients (33 eyes) with DME and treated with a single FAc implant between October 2013 and December 2016. This case, a 61-year-old male with a pseudophakic lens, is from a patient that had received 4 intravitreal injections of a DEX implant prior to FAc implant and then was monitored for 3 years until re-treatment with a second FAc implant. Parameters measured included visual acuity (VA), central retinal thickness (CRT), and intraocular pressure (IOP).

Results

After the DEX implants, CRT transiently improved. In March 2014, the decision was taken to administer an FAc implant, and this led to a reduction in CRT below 300 µm (from a baseline of 748 µm), and this was sustained for 30 months. VA remained above 65 Early Treatment Diabetic Retinopathy Study letters to month 36, after which time a second FAc implant (in April 2017) was administered due to recurrence of edema and CRT decreased to below 300 µm and VA improved to 70 letters. Side effects included elevated IOP, which was effectively managed with IOP-lowering drops.

Conclusion

A single injection of FAc implant led to sustained improvements in CRT and VA that lasted for between 30 and 36 months, which is in contrast to the DEX implant where re-treatment was generally required within 6–7 months. After 36 months, re-treatment with the FAc implant again led to improved VA and CRT, and responses that were similar to those achieved with the first FAc implant.

Premorbid Adjustment in Predicting Symptom Severity and Social Cognitive Deficits in Schizophrenia

OBJECTIVE

Schizophrenia patients have deficits in premorbid adjustment (PMA) and social cognition (SC); both deficits are associated with symptom severity, neuro-cognitive deficits, and prognosis. This study aimed to determine symptom severity and two domains of SC deficit by assessing specific areas of PMA in schizophrenia patients.

METHODS

This cross-sectional study included 60 male and 60 female patients with paranoid schizophrenia aged 20 to 35 years from two psychiatric inpatient departments of Chhattisgarh state of India. They were assessed using the Scale for Assessment of Positive Symptoms, Scale for Assessment of Negative Symptoms, Premorbid Adjustment Scale, Recognition of Facial Expression Task, and Picture Arrangement Test.

RESULTS

Deficits in premorbid sociability and in scholastic performance were the best predictors of severity of positive symptoms, social knowledge, and negative emotion recognition deficit in schizophrenia patients.

CONCLUSION

Given the important role of SC and PMA, assessing premorbid functioning can help in deciding early and appropriate intervention for schizophrenia.

Heparanase is expressed in adult human osteoarthritic cartilage and drives catabolic responses in primary chondrocytes

OBJECTIVES

The chondrocytes' pericellular matrix acts as a mechanosensor by sequestering growth factors that are bound to heparan sulfate (HS) proteoglycans. Heparanase is the sole mammalian enzyme with HS degrading endoglycosidase activity. Here, we aimed to ascertain whether heparanase plays a role in modulating the anabolic or catabolic responses of human articular chondrocytes.

METHODS

Primary chondrocytes were incubated with pro-heparanase and catabolic and anabolic gene expression was analyzed by quantitative polymerase chain reaction (PCR). MMP13 enzymatic activity in the culture medium was measured with a specific fluorescent assay. Extracellular regulated kinase (ERK) phosphorylation was evaluated by Western blot. Human osteoarthritis (OA) cartilage was assessed for heparanase expression by reverse-transcriptase PCR, by Western blot and by a heparanase enzymatic activity assay.

RESULTS

Cultured chondrocytes rapidly associated with and activated pro-heparanase. Heparanase induced the catabolic genes MMP13 and ADAMTS4 and the secretion of active MMP13, and down-regulated the anabolic genes ACAN and COL2A1. PG545, a HS-mimetic, inhibited the effects of heparanase. Heparanase expression and enzymatic activity were demonstrated in adult human osteoarthritic cartilage. Heparanase induced ERK phosphorylation in cultured chondrocytes and this could be inhibited by PG545, by fibroblast growth factor 2 (FGF2) neutralizing antibodies and by a FGF-receptor inhibitor.

CONCLUSIONS

Heparanase is active in osteoarthritic cartilage and induces catabolic responses in primary human chondrocytes. This response is due, at least in part, to the release of soluble growth factors such as FGF2.

Antilisterial effects of hop alpha and beta acids in turkey slurry at 7 and 37°C

Chemical components of hop resins effectively inhibit the growth of L. monocytogenes in microbiological culture media. This study was conducted to investigate antilisterial activities of hop α- and β-acid in turkey slurry. Turkey slurries were inoculated with L. monocytogenes, formulated with hop α- or β-acid from 0 to 1,000 ppm, and incubated at 37°C for 24 h or at 7°C for 12 days. During storage at 37°C for 24 h, L. monocytogenes populations were reduced from 2.40 log CFU/g to non-detectable (<1 log CFU/g) in α-acid at ≥750 ppm and β-acid at 1,000 ppm, whereas the control (0 ppm) allowed the pathogen to grow to 8.0 log CFU/g. During storage at 7°C for 12 d, the slurry treated with α-acid at ≥100 ppm and β-acid at ≥500 ppm showed listeristatic effects, while listericidal effects were observed in the slurries at 1,000 ppm, regardless of hop acid type. Hop α-acid ≤ 50 ppm and β-acid ≤ 100 ppm failed to inhibit L. monocytogenes, and the pattern of bacterial growth was similar to that of control with no significant difference (P > 0.05). Based on these results, the concentration of α-acid > 100 ppm or β-acid > 500 ppm is minimally required to inhibit L. monocytogenes when turkey batters are formulated with hop acids as a single antilisterial agent prior to cooking and storage at 7°C.

Identification of Malassezia species by MALDI-TOF MS after expansion of database

The taxonomy of Malassezia species is evolving with introduction of molecular techniques, and difficulty is faced to identify the species by phenotypic methods. Among 15 known Malassezia species, the present Bruker database could identify only 2 species. The present study was aimed to improve Matrix -assisted laser desorption ionization time-flight mass spectrometry (MALDI-TOF MS) based identification of Malassezia species. A total of 88 isolates (DNA sequencing confirmed) for database preparation and, for the validation of database, 190 isolates confirmed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) were used. The main spectrum profile dendrogram showed the sufficient discrimination between all the species by MALDI-TOF MS. The updated Malassezia database could identify 94.7% and 5.3% strains to the species and genus level, respectively. MALDI-TOF MS is a significantly reliable technique, and results were comparable with PCR-RFLP with kappa value 0.9. In conclusion, MALDI-TOF MS could be a possible alternative tool to other molecular methods for rapid and accurate identification of Malassezia species.

Evaluating the Role of Immunological Cells (Tissue Eosinophils and Mast Cells) in Progression of Oral Squamous Cell Carcinoma

Mast cells and eosinophils are increased in oral squamous cell carcinoma. The significance of such an association has been variably thought to be either a potential diagnostic tool for stromal invasion or as a prognostic indicator. The aim of the study was to study the mast cells and eosinophils between normal oral mucosa, leukoplakia and oral squamous cell carcinoma and to study the significance of mast cells in the progression of the lesion. A retrospective study was done on archival tissue received from January 2015 to December 2015, in the Department of Oral Pathology, RUHS College of Dental Sciences, Jaipur, Rajasthan, India. Seventy (70) cases were studied (30 cases each of leukoplakia and carcinoma and 10 cases of control group), sections were stained with toluidine blue solution to reveal mast cells. Eosinophils were studied in Haematoxylin & Eosin stained sections. Mast cell density significantly increased from: normal mucosa to oral leukoplakia to carcinoma, suggesting a role of the mast cells in the development of these lesions. The higher eosinophil counts in carcinoma group compared to dysplasia group proved that they might have a role in stromal invasion. The assessment of these could become, in the future, useful for therapeutic approaches in this subset of the patient.

Cross cultural comparison of constipation profiles at tertiary care centers between India and USA

BACKGROUND

Despite potential differences in patient perception of chronic constipation (CC) in geographically and culturally distinct regions, head-to-head studies comparing the clinical profile, constipation severity, impact on quality of life (QOL) and economic impact are lacking.

METHODS

We conducted a cross-sectional cohort study of patients presenting with CC to tertiary care centers in the USA and India. Standardized instruments were used to assess constipation subtype, disease severity, disease-specific QOL, somatization, and psychiatric comorbidities. We used multivariable linear regression to determine the predictors of QOL and number of healthcare visits.

KEY RESULTS

Sixty-six and 98 patients with CC were enrolled in the USA and India, respectively. Indian patients with CC had significantly more frequent bowel movements/week compared to their USA counterparts (Median 5 vs 3, P < .0001). The proportion of patients with Bristol stool form scale type 1 and 2 was significantly higher in the USA compared to India (65.5% vs 48%, P = .04). Higher depression score (P = .001), more severe constipation symptoms (P = .001) and site of the study being USA (P = .008) independently predicted worse QOL. Indian patients (P < .001) and worse QOL (P = .02) were independent predictors of number of healthcare visits in the last 12 months.

CONCLUSIONS AND INFERENCES

Indian patients with CC have more frequent and softer bowel movements compared to those in the USA suggesting significant differences in perception of CC in different geographic and cultural settings. QOL and economic impact related to constipation varies with geographic/cultural setting irrespective of other clinical and psychosomatic features.

Abstract GS2-02: Direct regulation of estrogen receptor-α (ER) transcriptional activity by NF1

Inactivating germline mutations in the NF1 gene (encoding neurofibromin) cause neurofibromatosis type 1. In addition to peripheral nervous system tumors, NF1 patients are at higher risk for other cancers, including breast cancer. Tumor exome-sequencing studies demonstrate that approximately 20% of all human cancers have somatic NF1 mutations. NF1 has been best known for its ability to inactivate Ras as a GAP (GTPase Activating Protein). However, this function is served by a small GAP domain in a very large protein. Recurrent missense mutations inactivating the GAP activity are infrequent. In contrast, it is common to detect frameshift (FS) and nonsense (NS) NF1 mutations, which can create an NF1-null state deleting not only GAP, but also, potentially, undefined NF1 functions whose loss could also drive tumorigenesis.

As we reported at SABCS previously, in 600+ patients treated by tamoxifen adjuvant monotherapy, we found that FS/NS NF1 mutations independently correlate with relapse risk (HR=2.6, p=0.03). To explore this finding, we silenced NF1 in preclinical models of ER+ breast cancer, which markedly enhanced ER transcriptional activities, causing estradiol (E2) hypersensitivity and converted tamoxifen into an agonist (in vitro and in vivo). Most important, these activities depend on ER, but not on NF1's GAP activity. These findings readily explain the poor patient outcomes associated with NS/FS NF1 mutations, and reveal a previously unrecognized function for NF1 in ER regulation.

In the presence of an agonist, liganded ER repels co-repressors and recruits co-activators, while the reverse is true with an antagonist such as tamoxifen. Many co-regulators contain leucine/isoleucine rich motifs, which bind directly to the ligand-binding domain (LBD) in ER. NF1 has several of these motifs that are much more highly conserved in species with a functional ER pathway, and some of these are mutated in cancers (e.g., in our patient cohort). Furthermore, we found that NF1 canbind directly to ER, and that this binding is mediated between the ER LBD and the NF1 leucine-rich regions. Like a classic co-repressor, wildtype NF1 (but not mutants lacking GAP activity or the Leu-rich motif) binds to ER, and is recruited by ER to the ERE in the presence of tamoxifen, but not E2.

Further preclinical treatment studies indicate that while NF1-deficient ER+ breast cancer should not be treated by tamoxifen or AIs, fulvestrant remains effective. Furthermore, when fulvestrant is combined with dabrafinib and trametinib to inhibit Ras effectors Raf and MEK, apoptosis is induced in vitro, and tumor regression is observed in vivo. In conclusion, we have demonstrated that NF1 is a dual negative regulator at the intersection of two potent oncogenic signaling pathways, Ras and ER, and that NF1-deficient ER+ breast cancer patients may be more effectively treated by co-targeting the Ras and ER signaling. These patients, up to 10% of those with advanced ER+ breast cancer, can be readily identified for treatment by ctDNA analysis. A clinical trial is under development.

Citation Format: Chang EC, Zheng Z, Philip L, Burcu C, Lei J, Singh P, Anurag M, Chan D, Li JD, Du XP, Shafaee MN, Banks K, Sacker S, Song W, Nguyen T, Cao J, Chen X, Haricharan S, Kavuri M, Kim B-J, Zhang B, Gutmann DH, Lanman RB, Foulds C, Ellis M. Direct regulation of estrogen receptor-α (ER) transcriptional activity by NF1 [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 GS2-02.

Abstract PD8-03: ESR1 gene fusions drive endocrine therapy resistance and metastasis in breast cancer

Background. Dysregulation of the estrogen receptor gene (ESR1) is an established mechanism of inducing endocrine therapy resistance. We previously discovered a chromosomal translocation event generating an estrogen receptor gene fused in-frame to C-terminal sequences of YAP1 (ESR1-YAP1) that contributed to endocrine therapy resistance in estrogen receptor positive (ER+) breast cancer models. This study compares functional, transcriptional, and pharmacological properties of additional ESR1 gene fusion events of both early stage (ESR1-NOP2) late stage (ESR1-YAP1 and ESR1-PCDH11x) breast cancers to gain a better understanding of therapeutic resistance and metastasis. Understanding the role of ESR1 fusions in inducing metastasis is critical, since the primary cause of death in breast cancer patients is through metastasis to distant sites.

Methods. RNA-seq screens identified ESR1 fusions from early and late stage, endocrine therapy resistant breast tumor samples. Functional experiments were conducted using ER+ breast cancer cell lines, xenograft, and PDX models to test the ability of ESR1 fusions to induce therapeutic resistance and metastasis. ChIP-seq and RNA-seq were performed to examine transcriptional properties and differential gene expression induced by the fusions which directed subsequent pharmacological experiments with a CDK4/6 inhibitor.

Results. ESR1-YAP1 and ESR1-PCDH11x promoted estrogen-independent and fulvestrant-resistant growth in vitro and induced greater tumor growth and increased metastatic capacity to the lungs of xenografted mice. In contrast, the ESR1-NOP2 fusion was sensitive to low estrogen conditions in vitro, and did not promote tumor growth. RNA-seq profiling revealed E2F targets pathway as the most highly enriched pathway induced by the ESR1 fusions. IHC revealed higher levels of pRb in ESR1-YAP1 and ESR1-PCDH11x xenograft tumors and subsequent CDK4/6 inhibition completely blocked tumor growth in an ESR1-YAP1 PDX model. Integrating RNA-seq with ChIP-seq data, we discovered a set of EMT and metastasis genes bound by all ESR1 fusions and WT-ER, but whose expression was strongly and uniquely up-regulated only by the ESR1-YAP1 and ESR1-PCDH11x fusions. These studies also revealed gained sites bound only by the ESR1-YAP1 and ESR1-PCDH11x fusions, not bound by WT-ER nor ESR1-NOP2. Genes mapping to these sites have a role in metastatic biology and were highly up-regulated by the YAP1 and PCDH11x fusions, potentially mediated by long range transcriptional activation.

Conclusion. ESR1-YAP1 and ESR1-PCDH11x are driver fusions that occur in drug-resistant, advanced stage breast cancer and are a new class of recurrent somatic mutation that can cause acquired endocrine therapy resistance, yet can be treated with CDK4/6 inhibition. These driver fusions also confer increased metastatic ability through their ability to drive expression of genes that contribute to EMT and metastasis. In contrast, ESR1-NOP2 did not produce functional protein and appears to be a passenger event. These studies may provide pre-clinical rationale for targeting ESR1 translocated breast tumors, since the presence of an ESR1 driver fusion places a patient in a therapeutic category where none of the currently available endocrine therapies are likely to be effective.

Citation Format: Lei JT, Shao J, Zhang J, Iglesia M, Chan DW, Cao J, Anurag M, Singh P, Haricharan S, Kavuri SM, Matsunuma R, Schmidt C, Kosaka Y, Crowder R, Hoog J, Phommaly C, Goncalves R, Ramalho S, Rodrigues-Peres RM, Lai W-C, Hampton O, Rogers A, Tobias E, Parikh P, Davies S, Ma C, Suman V, Hunt K, Watson M, Hoadley KA, Thompson A, Perou CM, Creighton CJ, Maher C, Ellis MJ. ESR1 gene fusions drive endocrine therapy resistance and metastasis in 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 PD8-03.

Abstract P5-06-01: Proteomic analysis of conserved kinases between PDX tumors and corresponding PDX-derived cell lines

(Background) Patient-derived xenograft (PDX)s are valuable models for precision oncology as they are thought to recapitulate the biological and genomic characteristics of the human tumors they were derived from. Even though this model is widely used, it is still difficult to manipulate genes in this system and it is not as convenient as in vitro cell culture for drug sensitivity screening. On the other hand in vitro cell cultures have a highly artificial microenvironment and also have undergone selection which might generate misleading data. To address these issues cell lines from PDX tumors with different intrinsic subtypes were characterized by kinobead precipitation/mass spectrometry analysis (KiP/MS) to profile each PDX line in vivo and ex vivo for therapeutic targets.

(Materials and Methods)Washington University Human in Mice (WHIM) tumors and Hutsman Cancer Institute (HCI) tumors were transplanted into mammary fat pads of female severe combined immunodeficiency/beige (SCID/beige) mice. PDXs tumors were harvested when they reached 1˜1.5cm. PDX tumor-derived ex vivo cells/organoids were routinely cultured with Rock inhibitor support. Estradiol was applied only for the tumors originating from E2 supplementation in vivo. Cells and tumors were harvested and lysed by sonication. Kinases in soluble lysates are enriched with drug-bound beads (kinobead) and digested with trypsin. Digested peptides are analyzed by mass spectrometry.

(Results) 5 of WHIM tumors and 4 of HCI tumors were successfully dissociated and cultured ex vivo for further analysis and experiments. Hierarchical clustering of tumors and corresponding cells showed ex vivo cultured cells cluster together with their original PDX tumors. Tumors/ex vivo cultured cells clustered by intrinsic subtype and enrichment analysis identified specific kinases for each PDX tumor/cell line. The WHIM 4 tumor-cell pair showed high level of PIM kinase and EGFR and other PDX tumors such as WHIM18, WHIM 20 (Luminal subtypes), WHIM 35(HER2 enriched subtype) also showed model unique intrinsic kinases, such as JAK2 for WHIM18, EPHB4 for WHIM20.

(Conclusion) PDX tumor-derived ex vivo lines could be routinely cultured with Rock inhibitor support. Each PDX tumor and cell line pair were cluster together in hierarchical clustering and categorized into the same intrinsic subtype based on kinome profiling, suggesting these cells maintain their tumor specific intrinsic kinase signaling. A subset of kinases exhibit activity/expression that is conserved after ex vivo culture, we hypothesize these are intrinsic kinases might be promising target for treatment, because they are tumor intrinsic, i.e. their high expression is maintained despite the strong contrast in the microenvironment of in vitro versus in vitro growth. Ongoing studies with drugs and knock down reagents are examining whether the in vivo/ex vivo comparative KIP analysis indeed identifies therapeutic targets, which will be presented at the meeting more in detail.

Citation Format: Han A, Kim B-J, Chan DW, Matsunuma R, Singh P, Ellis MJ. Proteomic analysis of conserved kinases between PDX tumors and corresponding PDX-derived cell lines [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 P5-06-01.

The Incremental Cost of Incompatible Living Donor Kidney Transplantation: A National Cohort Analysis

Incompatible living donor kidney transplantation (ILDKT) has been established as an effective option for end-stage renal disease patients with willing but HLA-incompatible living donors, reducing mortality and improving quality of life. Depending on antibody titer, ILDKT can require highly resource-intensive procedures, including intravenous immunoglobulin, plasma exchange, and/or cell-depleting antibody treatment, as well as protocol biopsies and donor-specific antibody testing. This study sought to compare the cost and Medicare reimbursement, exclusive of organ acquisition payment, for ILDKT (n = 926) with varying antibody titers to matched compatible transplants (n = 2762) performed between 2002 and 2011. Data were assembled from a national cohort study of ILDKT and a unique data set linking hospital cost accounting data and Medicare claims. ILDKT was more expensive than matched compatible transplantation, ranging from 20% higher adjusted costs for positive on Luminex assay but negative flow cytometric crossmatch, 26% higher for positive flow cytometric crossmatch but negative cytotoxic crossmatch, and 39% higher for positive cytotoxic crossmatch (p < 0.0001 for all). ILDKT was associated with longer median length of stay (12.9 vs. 7.8 days), higher Medicare payments ($91 330 vs. $63 782 p < 0.0001), and greater outlier payments. In conclusion, ILDKT increases the cost of and payments for kidney transplantation.

The dynamics of benzene on Cu(111): a combined helium spin echo and dispersion-corrected DFT study into the diffusion of physisorbed aromatics on metal surfaces

We use helium spin-echo spectroscopy (HeSE) to investigate the dynamics of the diffusion of benzene adsorbed on Cu(111). The results of these measurements show that benzene moves on the surface through an activated jump-diffusion process between the adsorption sites on a Bravais lattice. Density Functional Theory (DFT) calculations with van der Waals (vdW) corrections help us understand that the molecule diffuses by jumping through non-degenerate hollow sites. The results of the calculations shed light on the nature of the binding interaction between this prototypical aromatic molecule and the metallic surface. The highly accurate HeSE experimental data provide a quantitatively stringent benchmark for the vdW correction schemes applied to the DFT calculations and we compare the performances of several dispersion interaction schemes.

Evolution of ramucirumab in the treatment of cancer - A review of literature

Ramucirumab is a recombinant human monoclonal antibody and is used in the treatment of advanced malignancies. Its mechanism of action is by inhibiting angiogenesis in tumor cells by targeting the vascular endothelial growth factor receptor 2. United States Food and Drug Administration (FDA) approved it initially in 2014 for the treatment of advanced gastric or gastro-esophageal junction adenocarcinoma and metastatic non-small cell lung carcinoma. It was approved by FDA in 2015 for the treatment of advanced colorectal cancer. This manuscript consolidates pre-clinical trials to phase I, II, and III trial data indicating the effects of ramucirumab on different cancer types, which led to its approval. By comparing these clinical trials alongside each other, we can more easily examine the studies that have already been completed, along with currently ongoing studies and potential further areas of interest for this newly approved treatment. This approach makes it convenient to compare dosages, overall survival, adverse events, as well as possible routes for combination therapy with ramucirumab. By compiling results for various oncological malignancies, we can differentiate between treatments that are effective and have the highest incidence of stable disease, and those that do not seem promising. Ramucirumab has been effective in the treatment of various carcinomas and this article outlines other tumors in which this treatment option may be successful.

The management of pretibial lacerations

Introduction Pretibial lacerations are common injuries, often presenting in the elderly and infirm. Unclear management pathways often result in inappropriate care. We identify patient demographics, morbidity risk factors, injury severity and management options. Materials and methods This retrospective study involved analysing databases and hardcopy notes for patients admitted with pretibial lacerations to Addenbrooke's Hospital, January to December 2012. Microsoft Excel and Fishers exact test were used to analyse the data with a P-value of less than 0.05 representative of statistical significance. Information on patient demographics, site of lesion, preoperative symptoms, management, operative details and clinical outcomes were collected. Results A total of 36 patients were identified; the mean age was 79 years (± 16 years, 1 standard deviation) with a three to two female to male preponderance; 57% of injuries were caused by mechanical fall, 33% traumatic blunt impact and 7% road traffic accidents. American Society of Anesthesiologists physical status classification was 43% level III, 40% II, 9% I and 9% IV. Dunkin classification of severity was 33% grade III, 30% grade I, 24% grade IV and 12% grade II. Median inpatient duration was 11 days for surgically managed compared with 15 days for conservatively managed patients. Discussion Pretibial lacerations tend to affect the elderly. Management is compounded by polypharmacy and comorbidities. If inadequately managed, such injuries can adopt characteristics of chronic wounds, with lengthy inpatient stays. Surgical intervention may be appropriate where injuries are severe and the patient stable enough for theatre. Conclusions We believe that surgical management with autologous tissue repair, with minimal delay between presentation and theatre, is warranted for extensive injuries wherever possible, with conservative management used for predominantly less extensive pretibial lacerations.

Monitoring of biofilm aging in a Sphingomonas sp. strain from public drinking water sites through changes in capacitance

This study reports the applicability of a capacitance-based technique for evaluating the biofilm progression of Sphingomonas sp. One hundred and forty isolates of Sphingomonas were screened from public drinking water sites, and one potential strain with biofilm-forming ability was used for the study. The biofilm production by this strain was established in microtiter plates and aluminum coupons. The standard biofilm-forming strain Sphingomonas terrae MTCC 7766 was used for comparison. Changes in biofilm were analyzed by energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM). Capacitance values were measured at 1, 100 and 200 kHz frequency; however, 1 kHz was selected since resulted in reproducible values, which could be correlated to biofilm age measured as dry weight over a time of 96 h (4 days) depicting the biofilm growth/progression over time. The EDX, SEM and capacitance values obtained in parallel indicated the related physiological profile usually displayed by biofilms upon growth, suggesting authenticity to the observed capacitance profile. The results of this study demonstrated the feasibility of a capacitance-based method for analyzing biofilm development/progression by Sphingomonas sp. and suggested a simple approach for developing an online system to detect biofilms by this opportunistic pathogen of concern in drinking water.

Clinical and radiological predictors of outcome in tubercular meningitis: A prospective study of 209 patients

OBJECTIVES

The predictors of poor outcome in tuberculous meningitis (TBM) remain to be delineated. We determined role of various clinical, radiological and cerebrospinal fluid (CSF) parameters in prediction of outcome in TBM.

PATIENTS AND METHODS

Current study was a prospective observational study including 209 patients of TBM. All patients underwent detailed evaluation including Gadolinium enhanced Magnetic resonance imaging (GdMRI) of brain as well as tests to detect evidence of tuberculosis elsewhere in body. They also underwent GdMRI at three and nine month follow up. All patients received treatment as per standard guidelines.

RESULTS

Mean age was 30.4±13.8years. 139 (66.5%) patients had definite TBM while 70 (34.5%) had highly probable TBM. 53 (25.4%) patients died. On univariate analysis, longer duration of illness, altered sensorium, stage III TBM, hydrocephalus and exudates correlated with poor outcome. On multivariate analysis presence of hydrocephalus (p=0.003; OR=3.2; 95% CI=1.5-6.7) and stage III TBM (p<0.0001; OR=8.7; 95% CI=3.7-20.2) correlated with higher risk of mortality. In addition, there was significant positive association between presence of hydrocephalus (p=0.05; OR=2.2; 95% CI=0.97-5.1), stage III TBM (p<0.0001; OR=28; 95% CI=4.9-158) and presence of altered sensorium (p=0.05; OR=22; 95% CI=0.99-4.8) with either death or survival with severe disability.

CONCLUSIONS

It is possible to prognosticate TBM using a combination of clinical and radiological. The duration of illness (65.9±92days) before diagnosis of TBM continues to be unacceptably long and this stresses on need to educate primary care physicians about TBM. Future studies where intensity and duration of treatment is guided by these cues may help in sorting out some of the most difficult questions in TBM, namely duration of antitubercular therapy as well as dose and duration of steroid therapy etc.

Family-led rehabilitation after stroke in India (ATTEND): a randomised controlled trial

BACKGROUND

Most people with stroke in India have no access to organised rehabilitation services. The effectiveness of training family members to provide stroke rehabilitation is uncertain. Our primary objective was to determine whether family-led stroke rehabilitation, initiated in hospital and continued at home, would be superior to usual care in a low-resource setting.

METHODS

The Family-led Rehabilitation after Stroke in India (ATTEND) trial was a prospectively randomised open trial with blinded endpoint done across 14 hospitals in India. Patients aged 18 years or older who had had a stroke within the past month, had residual disability and reasonable expectation of survival, and who had an informal family-nominated caregiver were randomly assigned to intervention or usual care by site coordinators using a secure web-based system with minimisation by site and stroke severity. The family members of participants in the intervention group received additional structured rehabilitation training-including information provision, joint goal setting, carer training, and task-specific training-that was started in hospital and continued at home for up to 2 months. The primary outcome was death or dependency at 6 months, defined by scores 3-6 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) as assessed by masked observers. Analyses were by intention to treat. This trial is registered with Clinical Trials Registry-India (CTRI/2013/04/003557), Australian New Zealand Clinical Trials Registry (ACTRN12613000078752), and Universal Trial Number (U1111-1138-6707).

FINDINGS

Between Jan 13, 2014, and Feb 12, 2016, 1250 patients were randomly assigned to intervention (n=623) or control (n=627) groups. 33 patients were lost to follow-up (14 intervention, 19 control) and five patients withdrew (two intervention, three control). At 6 months, 285 (47%) of 607 patients in the intervention group and 287 (47%) of 605 controls were dead or dependent (odds ratio 0·98, 95% CI 0·78-1·23, p=0·87). 72 (12%) patients in the intervention group and 86 (14%) in the control group died (p=0·27), and we observed no difference in rehospitalisation (89 [14%]patients in the intervention group vs 82 [13%] in the control group; p=0·56). We also found no difference in total non-fatal events (112 events in 82 [13%] intervention patients vs 110 events in 79 [13%] control patients; p=0·80).

INTERPRETATION

Although task shifting is an attractive solution for health-care sustainability, our results do not support investment in new stroke rehabilitation services that shift tasks to family caregivers, unless new evidence emerges. A future avenue of research should be to investigate the effects of task shifting to health-care assistants or team-based community care.

FUNDING

The National Health and Medical Research Council of Australia.

H2O2 sensing through electrochemically deposited thionine coated ITO thin film

Progression and initiation of different diseases including pulmonary diseases, alzheimer's and tumors are linked with the oxidative stress, an important cause of cell damage. Different antioxidant enzymes are involved in detoxifying reactive oxygen species including hydrogen peroxide (H2O2) that is generated in response to various stimuli and has important role in cell activation &amp; bio-signaling processes. Herein, we developed hydrogen peroxide electrochemical sensor based on horseradish peroxidase (HRP) entrapped polymerized thionine (PTH) film. Electrochemical deposition of thionine (dye) on indium tin oxide (ITO) surface was carried out through chornoamperometry followed by cyclic voltammetry. Deposited thionine thin film obtained was checked for its stability at different scan rates. The PTH-modified electrodes showed linear dependence of peak current with scan rate within the range of 20 to 100 mV s-1. Thionine used as electron transfer mediator between heme site of HRP and electrode. Cyclic voltammetry showed increase in the reduction peak current due to electrocatalytic reduction of H2O2. The sensor detection limit range from 10-1 _ 102 µM and limit of detection was 0.1µM. The proposed sensor has good storage response, cost effective, high sensitivity and wide linear range that could be used for the fabrication of other enzyme based biosensors.

Single-cell profiling reveals heterogeneity and functional patterning of GPCR expression in the vascular system

G-protein-coupled receptor (GPCR) expression is extensively studied in bulk cDNA, but heterogeneity and functional patterning of GPCR expression in individual vascular cells is poorly understood. Here, we perform a microfluidic-based single-cell GPCR expression analysis in primary smooth muscle cells (SMC) and endothelial cells (EC). GPCR expression is highly heterogeneous in all cell types, which is confirmed in reporter mice, on the protein level and in human cells. Inflammatory activation in murine models of sepsis or atherosclerosis results in characteristic changes in the GPCR repertoire, and we identify functionally relevant subgroups of cells that are characterized by specific GPCR patterns. We further show that dedifferentiating SMC upregulate GPCRs such as Gpr39, Gprc5b, Gprc5c or Gpr124, and that selective targeting of Gprc5b modulates their differentiation state. Taken together, single-cell profiling identifies receptors expressed on pathologically relevant subpopulations and provides a basis for the development of new therapeutic strategies in vascular diseases.

GPCRs are key regulators of vascular functions. By analysing single-cell GPCRs expression in vascular smooth muscle and endothelial cells from healthy and diseased murine vessels, Kaur et al. show that GPCR expression is highly heterogeneous in all cell types and that disease causes GPCR repertoire changes depending on cell type and vascular localization.

Monodora myristica (African nutmeg) modulates redox homeostasis and alters functional chemistry in sickled erythrocytes

The antioxidative effect of Monodora myristica seed acetone extract and its effect on chemical functional groups were investigated in sickled erythrocytes as well as molecular modeling of the antisickling potentials of its secondary metabolites. The extract was subjected to gas chromatography–mass spectrometry to identify the compounds present, which were then docked into the allosteric-binding site of deoxy-hemoglobin. The extract was incubated with sickled erythrocytes at 37°C for 6, 12, and 24 h and were subjected to antioxidative analysis for reduced glutathione (GSH), superoxide dismutase (SOD), catalase, and lipid peroxidation (LPO). Chemical functional group of the treated cells was analyzed via Fourier transform infrared spectroscopy (FTIR). The predominant compounds identified were 17-octadecynoic acid; oleic acid, androstan-3-one, 17-hydroxy-2-methyl- (2.beta.,5.beta.,17.beta.)-; estran-3-one, 17-(acetyloxy)-2-methyl-, (2.alpha., 5.alpha., 17.beta.), and (+)-3-carene, 10-(acetylmethyl)-. They all fitted well within the active site of Hb with good binding affinity, as evidenced by the negative CDocker interaction energies of their complexes ranging between −54.4 and −26.7 kcal/mol. Treatment with the extract exacerbated SOD and catalase activities as well as GSH level, while LPO was suppressed. This antioxidative activity was time and/or dose dependent, with 6 and 12 h incubation showing the optimum activity. FTIR analysis of the treated cells showed the presence of hydrophobic functional groups. The synergetic molecular interaction of the major compounds of the extract with the α-dimer of Hb depicts an antisickling effect of M. myristica acetone extract. This is accompanied by exacerbation of endogenous antioxidant enzymes activity and modification of the functional chemistry of the cells.

Synthesis maps: visual knowledge translation for the CanIMPACT clinical system and patient cancer journeys

Salient findings and interpretations from the canimpact clinical cancer research study are visually represented in two synthesis maps for the purpose of communicating an integrated presentation of the study to clinical cancer researchers and policymakers. Synthesis maps integrate evidence and expertise into a visual narrative for knowledge translation and communication. A clinical system synthesis map represents the current Canadian primary care and cancer practice systems, proposed as a visual knowledge translation from the mixed-methods canimpact study to inform Canadian clinical research, policy, and practice discourses. Two synthesis maps, drawn together from multiple canimpact investigations and sources, were required to articulate critical differences between the clinical system and patient perspectives. The synthesis map of Canada-wide clinical cancer systems illustrates the relationships between primary care and the full cancer continuum. A patient-centred map was developed to represent the cancer (and primary care) journeys as experienced by breast and colorectal cancer patients.