Remus Osan

Human papillomavirus-negative (HPV-neg) oropharyngeal squamous cell carcinomas (OPSCCs) are associated with poorer overall survival (OS) compared with HPV-positive (HPV-pos) OPSCCs. The major obstacle in improving outcomes of HPV-neg patients is the lack of robust biomarkers and therapeutic targets. Herein, we investigated the role of centrosome amplification (CA) as a prognostic biomarker in HPV-neg OPSCCs. A quantitative evaluation of CA in clinical specimens of OPSCC revealed that (a) HPV-neg OPSCCs exhibit higher CA compared with HPV-pos OPSCCs, and (b) CA was associated with poor OS, even after adjusting for potentially confounding clinicopathologic variables. Contrastingly, CA was higher in HPV-pos cultured cell lines compared to HPV-neg ones. This divergence in CA phenotypes between clinical specimens and cultured cells can therefore be attributed to an inaccurate recapitulation of the in vivo tumor microenvironment in the cultured cell lines, namely a hypoxic environment. The exposure of HPV-neg OPSCC cultured cells to hypoxia or stabilizing HIF-1α genetically increased CA. Both the 26-gene hypoxia signature as well as the overexpression of HIF-1α positively correlated with increased CA in HPV-neg OPSCCs. In addition, we showed that HIF-1α upregulation is associated with the downregulation of miR-34a, increase in CA and expression of cyclin- D1. Our findings demonstrate that the evaluation of CA may aid in therapeutic decision-making, and CA can serve as a promising therapeutic target for HPV-neg OPSCC patients.

Gut dysbiosis is observed in several neuropsychiatric disorders exhibiting increases in anxiety behavior, and recent work suggests links between gut inflammation and such disorders. One source of this inflammation may be lipopolysaccharide (LPS), a toxic component of gram-negative bacteria. Here, we (1) determine whether oral gavage of LPS, as a model of gut-derived endotoxemia, affects anxiety-like and/or repetitive behaviors; (2) test whether these changes depend on TLR4 signaling; and (3) test the extent to which gut-derived endotoxin and TLR4 antagonism affects males and females differently. In experiment 1, male wild-type (WT) and Tlr4−/− mice were tested for locomotor, anxiety-like, and repetitive behaviors in an automated open field test apparatus, 2 h after oral gavage of LPS or saline. In experiment 2, male and female WT mice received an oral gavage of LPS and an injection of one or two TLR4 antagonists that target different TLR4 signaling pathways ((+)-naloxone and LPS derived from R. sphaeroides (LPS-RS)). Univariate and multivariate analyses were used to identify effects of treatment, sex, and genotype and their interaction. In experiment 1, oral gavage of LPS increased anxiety-like behavior in male WT mice but not in Tlr4−/− mice. In experiment 2, oral gavage of LPS increased anxiety-like and decreased repetitive behaviors in WT mice of both sexes. Neither antagonist directly blocked the effects of orally administered LPS. However, treatment with (+)-naloxone, which blocks the TRIF pathway of TLR4, had opposing behavioral effects in males and females (independent of LPS treatment). We also identified sex differences in the expression of interleukin-6, a pro-inflammatory cytokine, in the gut both in basal conditions and in response to LPS. In spite of the ubiquitous nature of LPS in the gut lumen, this is the first study to demonstrate that intestinally derived LPS can initiate behavioral aspects of the sickness response. While an increased enteric load of LPS increases anxiety-like behavior in both sexes, it likely does so via sex-specific mechanisms. Similarly, TLR4 signaling may promote baseline expression of repetitive behavior differently in males and females. This study lays the groundwork for future interrogations into connections between gut-derived endotoxin and behavioral pathology in males and females.

Clinical studies have revealed a higher risk of breast tumor recurrence in African-American (AA) patients compared to European-American (EA) patients, contributing to the alarming inequality in clinical outcomes among the ethnic groups. However, distinctions in recurrence patterns upon receiving hormone, radiation, and/or chemotherapy between the races remain poorly characterized. We compared patterns and rates (per 1000 cancer patients per 1 year) of recurrence following each form of treatment between AA (n = 1850) and EA breast cancer patients (n = 7931) from a cohort of patients (n = 10504) treated between 2005–2015 at Northside Hospital in Atlanta, GA. Among patients who received any combination of adjuvant therapy, AA displayed higher overall rates of recurrence than EA (p = 0.015; HR: 1.699; CI: 1.108–2.606). Furthermore, recurrence rates were higher in AA than EA among stage I (p = 0.031; HR: 1.736; CI: 1.052–2.864) and T1 classified patients (p = 0.003; HR: 2.009; CI: 1.263–3.197). Interestingly, among patients who received neoadjuvant chemotherapy, AA displayed higher rates of local recurrence than EA (p = 0.024; HR: 7.134; CI: 1.295–39.313). Our analysis revealed higher incidence rates of recurrence in AA compared to EA among patients that received any combination of adjuvant therapy. Moreover, our data demonstrates an increased risk of tumor recurrence in AA than EA among patients diagnosed with minimally invasive disease. This is the first clinical study to suggest that neoadjuvant chemotherapy improves breast cancer recurrence rates and patterns in AA.

In contrast to other large-scale network models for propagation of electrical activity in neural tissue that have no analytical solutions for their dynamics, we show that for a specific class of integrate and fire neural networks the acceleration depends quadratically on the instantaneous speed of the activity propagation. We use this property to analytically compute the network spike dynamics and to highlight the emergence of a natural time scale for the evolution of the traveling waves. These results allow us to examine other applications of this model such as the effect that a nonconductive gap of tissue has on further activity propagation. Furthermore we show that activity propagation also depends on local conditions for other more general connectivity functions, by converting the evolution equations for network dynamics into a low-dimensional system of ordinary differential equations. This approach greatly enhances our intuition into the mechanisms of the traveling waves evolution and significantly reduces the simulation time for this class of models.

1091 Background: Ki67 Index (KI) and Mitotic Index (MI) are proliferation markers with established prognostic value in breast cancer. These indices are evaluated individually and on disparate measurement scales; they therefore fail to capture information about cell cycling kinetics of proliferating cells. Methods: Pathology reports of breast cancer patients (n = 10,504 from Northside Hospital, Atlanta and n = 1560 from Nottingham Hospital, UK) were retrospectively analyzed for mitotic scores, KI and clinical outcomes. Mitotic counts in 267 H&E-stained breast carcinoma samples were evaluated by two pathologists to transform mitotic scores into %MI based on cellularity. %MI: %KI ratio was defined as the Ki67 Adjusted Mitotic Score (KAMS), which reflects cycling kinetics of proliferative cells. Ability of KAMS to stratify triple negative breast cancers (TNBCs) was tested in three cohorts who received only adjuvant chemotherapy (n = 478 from Northside Hospital, USA; n = 322 from Nottingham Hospital, UK, and n = 108 from Olabisi Onabanjo University, Nigeria). Stratification of KAMS, KI and MI were performed on the thresholds that produced the lowest AIC (best model fit). Slow cycling and fast cycling TNBC subgroups from Nottingham Hospital were analyzed for biomarker expression. Results: Kaplan-Meier survival analyses, AIC and c²values showed that KAMS based stratification of TNBCs into two subgroups was superior to that by either KI or MI, regardless of hospital, and KAMS retained its significance in multivariate analyses. Fast-cycling TNBCs have poorer prognosis than slow-cycling TNBCs, perhaps due to higher intratumoral heterogeneity in fast cycling tumors. Fast-cycling TNBCs showed high expression of proteins implicated in DNA damage response, sumoylation, EGFR signaling and metastasis. By contrast, slow-cycling TNBCs showed extensive chromatin modification. Conclusions: KAMS quantifies cell cycling kinetics, stratifies TNBCs and yields new risk-predictive information that is not revealed by either KI or MI. KAMS reveals the underlying heterogeneity in cycling kinetics among TNBCs and helps identify TNBCs who might benefit from treatments that target the cell cycle machinery.

1089 Background: Triple Negative Breast Cancer (TNBC) is a highly heterogeneous and aggressive breast carcinoma subtype typified by high recurrence and mortality rates. To date, no targeted therapies are available for TNBC. Recently, androgen receptor (AR), a nuclear steroid hormone receptor expressed in 10-43% of TNBCs, has emerged as a promising new biomarker with potential predictive value for certain TNBC subtypes. Compared to European-American (EA) women, African Americans (AAs) are twice as likely to develop TNBC and have poorer outcomes, than EA TNBC patients, after adjusting for treatment and healthcare access. This study aimed to determine the prognostic value of AR in a large TNBC cohort and evaluate racewise trends in AR expression status among TNBCs. Methods: AR expression was evaluated immunohistochemically in formalin-fixed paraffin-embedded samples from 822 TNBC patients (142, 95 and 264 patients from Emory, Northside and Grady Memorial Hospitals, respectively, in Atlanta, and 321 from Nottingham Hospital, UK) for whom complete clinicopathologic and overall survival (OS) data were available. Ethnicity data were available for 138 AA and 675 EA TNBC cases. Samples with < 1% nuclear-stained cells were considered quadruple-negative (QN). Associations between nuclear AR status, race, other clinicopathologic variables and OS were evaluated through survival analyses and multivariate Cox regression. Results: In this study, 45.6% of the TNBC cases were QN. QN receptor status was significantly associated with older age (age > 25) at diagnosis, AA ethnicity and lower (KI < 14%) proliferative index (p < 0.001 for all) in univariate analyses. In multivariate analyses, loss of AR expression was associated with poorer OS (p < 0.05, HR = 2.8) after adjusting for grade, stage and adjuvant therapy. Interestingly, AAs had a much higher proportion (80.8%) of QN cases than EAs (40.1%, p < 0.0001). Conclusions: These data strongly support a prognostic role of AR in TNBC and suggest that a higher prevalence of QN breast cancer among AAs may be a plausible reason for the ethnic disparity in outcomes among TNBC patients.

Amplified centrosomes in cancers are recently garnering a lot of attention as an emerging hub of diagnostic, prognostic and therapeutic targets. Ovarian adenocarcinomas commonly harbor supernumerary centrosomes that drive chromosomal instability. A centrosome clustering molecule, KIFC1, is indispensable for the viability of extra centrosome-bearing cancer cells, and may underlie progression of ovarian cancers.