The impact of kit, environment, and sampling contamination on the observed microbiome of bovine milk

In low-microbial biomass samples such as bovine milk, contaminants can outnumber endogenous bacteria. Because of this, milk microbiome research suffers from a critical knowledge gap, namely, does non-mastitis bovine milk contain a native microbiome? In this study, we sampled external and internal mammary epithelia and stripped and cisternal milk and used numerous negative controls, including air and sampling controls and extraction and library preparation blanks, to identify the potential sources of contamination. Two algorithms were used to mathematically remove contaminants and track the potential movement of microbes among samples. Results suggest that the majority (i.e., >75%) of sequence data generated from bovine milk and mammary epithelium samples represents contaminating DNA. Contaminants in milk samples were primarily sourced from DNA extraction kits and the internal and external skin of the teat, while teat canal and apex samples were mainly contaminated during the sampling process. After decontamination, the milk microbiome displayed a more dispersed, less diverse, and compositionally distinct bacterial profile compared with epithelial samples. Similar microbial compositions were observed between cisternal and stripped milk samples, as well as between teat apex and canal samples. Staphylococcus and Acinetobacter were the predominant genera detected in milk sample sequences, and bacterial culture showed growth of Staphylococcus and Corynebacterium spp. in 50% (7/14) of stripped milk samples and growth of Staphylococcus spp. in 7% (1/14) of cisternal milk samples. Our study suggests that microbiome data generated from milk samples obtained from clinically healthy bovine udders may be heavily biased by contaminants that enter the sample during sample collection and processing workflows.IMPORTANCEObtaining a non-contaminated sample of bovine milk is challenging due to the nature of the sampling environment and the route by which milk is typically extracted from the mammary gland. Furthermore, the very low bacterial biomass of bovine milk exacerbates the impacts of contaminant sequences in downstream analyses, which can lead to severe biases. Our finding showed that bovine milk contains very low bacterial biomass and each contamination event (including sampling procedure and DNA extraction process) introduces bacteria and/or DNA fragments that easily outnumber the native bacterial cells. This finding has important implications for our ability to draw robust conclusions from milk microbiome data, especially if the data have not been subjected to rigorous decontamination procedures. Based on these findings, we strongly urge researchers to include numerous negative controls into their sampling and sample processing workflows and to utilize several complementary methods for identifying potential contaminants within the resulting sequence data. These measures will improve the accuracy, reliability, reproducibility, and interpretability of milk microbiome data and research.

Exploring associations between the teat apex metagenome and Staphylococcus aureus intramammary infections in primiparous cows under organic directives

The primary objective of this study was to identify associations between the prepartum teat apex microbiome and the presence of Staphylococcus aureus intramammary infections (IMI) in primiparous cows during the first 5 weeks after calving. We performed a case-control study using shotgun metagenomics of the teat apex and culture-based milk data collected longitudinally from 710 primiparous cows on five organic dairy farms. Cases had higher odds of having S. aureus metagenomic DNA on the teat apex prior to parturition compared to controls (OR = 38.9, 95% CI: 14.84-102.21). Differential abundance analysis confirmed this association, with cases having a 23.8 higher log fold change (LFC) in the abundance of S. aureus in their samples compared to controls. Of the most prevalent microorganisms in controls, those associated with a lower risk of post-calving S. aureus IMI included Microbacterium phage Min 1 (OR = 0.37, 95% CI: 0.25-0.53), Corynebacterium efficiens (OR = 0.53, 95% CI: 0.30-0.94), Kocuria polaris (OR = 0.54, 95% CI: 0.35-0.82), Micrococcus terreus (OR = 0.64, 95% CI: 0.44-0.93), and Dietzia alimentaria (OR = 0.45, 95% CI: 0.26-0.75). Genes encoding for Microcin B17 AMPs were the most prevalent on the teat apex of cases and controls (99.7% in both groups). The predicted abundance of genes encoding for Microcin B17 was also higher in cases compared to controls (LFC 0.26).

IMPORTANCE

Intramammary infections (IMI) caused by Staphylococcus aureus remain an important problem for the dairy industry. The microbiome on the external skin of the teat apex may play a role in mitigating S. aureus IMI risk, in particular the production of antimicrobial peptides (AMPs) by commensal microbes. However, current studies of the teat apex microbiome utilize a 16S approach, which precludes the detection of genomic features such as genes that encode for AMPs. Therefore, further research using a shotgun metagenomic approach is needed to understand what role prepartum teat apex microbiome dynamics play in IMI risk.

Asymmetric comb waveguide for strong interactions between atoms and light

Coupling quantum emitters and nanostructures, in particular cold atoms and optical waveguides, has recently raised a large interest due to unprecedented possibilities of engineering light-matter interactions. In this work, we propose a new type of periodic dielectric waveguide that provides strong interactions between atoms and guided photons with an unusual dispersion. We design an asymmetric comb waveguide that supports a slow mode with a quartic (instead of quadratic) dispersion and an electric field that extends far into the air cladding for an optimal interaction with atoms. We compute the optical trapping potential formed with two guided modes at frequencies detuned from the atomic transition. We show that cold Rubidium atoms can be trapped as close as 100 nm from the structure in a 1.3-mK-deep potential well. For atoms trapped at this position, the emission into guided photons is largely favored, with a beta factor as high as 0.88 and a radiative decay rate into the slow mode 10 times larger than the free-space decay rate. These figures of merit are obtained at a moderately low group velocity of c/50.

Assessment of FOXC1 expression as a predictor of response to neoadjuvant taxane plus platinum regimens in primary triple-negative breast cancer: Retrospective analysis of three clinical trial cohorts

569

Background: Taxane and platinum (TP) NAC regimens, e.g. Carboplatin and Docetaxel (CbD), in TNBC are currently of great interest, having good pathologic complete response (pCR) rates but with a significantly more manageable toxicity profile compared to anthracycline-based NAC regimens. Forkhead Box C1 (FOXC1), a transcriptional driver of cell plasticity/partial EMT/metastasis is an established mesenchymal marker diagnostic of basal-like breast cancer having proven prognostic value, but of uncertain predictive value. We sought to evaluate the potential of FOXC1 in predicting pCR to neoadjuvant TP regimens in patients diagnosed with TNBC. Methods: Pre-NAC tumor biopsy FOXC1 mRNA expression status was correlated with rate of pCR in a pooled, ambispective cohort (prospective cohort GEICAM/2006-03, NCT00432172 pooled with multi-institutional retrospective cohort, n = 119). A specific FOXC1 mRNA expression cutoff value was derived to maximize Negative Predictive Value (NPV) and Sensitivity for pCR prediction. The pCR-predictive ability of FOXC1 mRNA expression was then assessed in two validation cohorts of evaluable patients who had been enrolled in prospective clinical trials (UCONN/FIOCRUZ, n = 222, HGUGM, NCT01560663, n = 221). All evaluated patients had been diagnosed with TNBC and had received a Taxane plus Platinum-based NAC regimen. Results: FOXC1 mRNA expression was associated with pCR in CbD/TP treated TNBC patients with pCR rates of 43.48%, 47.89% and 52.73% observed in the discovery and two validation cohorts (two tailed T-test p-values of 0.0005, 0.002, 0.009, respectively). FOXC1 expression above the pre-determined cutoff value was associated with pCR to CbD/TP NAC in patients diagnosed with TNBC in both validation cohorts (OR 4.894, 1.504-15.924; p = 0.004 and OR 2.293, 1.208-4.352; p = 0.006). Conclusions: We report the retrospective validation of pre-NAC breast cancer biopsy FOXC1 mRNA expression for predicting efficacy of CbD/TP NAC in two independent, prospectively accrued TNBC patient cohorts. The described strategy may be acceptable for patient stratification to guide CbD/TP NAC recommendations in TNBC. FOXC1 mRNA or protein expression, assessed using qRT-PCR or routine immunohistochemistry (IHC), respectively, could potentially be utilized in future fixed-arm/adaptive clinical trials to further optimize NAC efficacy, in terms of achieved pCR rates, and to extend disease-free survival in patients diagnosed with TNBC.

Molecular insights into enhanced resistance of Papaver somniferum against downy mildew by application of endophyte bacteria Microbacterium sp. SMR1

Downy mildew is one of the most serious diseases of Papaver somniferum. Endophytes isolated from different parts of P. somniferum were screened for their ability to enhance resistance against downy mildew caused by the obligate biotrophic oomycete Peronospora meconopsidis. Two endophytes (SMR1 and SMR2) reduced the downy mildew on three P. somniferum genotypes (Sampada, J-16, and I-14). SMR1 (Microbacterium sp.) also enhanced the resistance of P. somniferum against downy mildew under field conditions. The biochemical markers of plant susceptibility under biotic stresses (proline and malondialdehyde) were found to be reduced in P. somniferum upon SMR1 treatment. To understand the mechanisms underlying the enhanced resistance to downy mildew in SMR1 endophyte-treated P. somniferum genotype J-16, we compared the expression profiles using the next-generation RNA sequencing approach between P. somniferum pretreated with SMR1 and untreated endophyte-free control plants following exposure to downy mildew pathogen. Comparative transcriptome analysis revealed differential expression of transcripts belonging to broad classes of signal transduction, protein modification, disease/defense proteins, transcription factors, and phytohormones in SMR1-primed P. somniferum after infection with downy mildew pathogen. Furthermore, enhanced salicylic acid content was observed in SMR1-primed P. somniferum after exposure to downy mildew pathogen. This study sheds light on molecular mechanisms underlying enhanced resistance to downy mildew in SMR1-primed P. somniferum. Finally, we propose that the SA-dependent defense pathway, the hallmark of systemic acquired resistance, is activated in SMR1-primed P. somniferum, triggering the endophyte-induced resistance.

Therapeutically Targeting Cancers That Overexpress FOXC1: A Transcriptional Driver of Cell Plasticity, Partial EMT, and Cancer Metastasis

Metastasis accounts for more than 90% of cancer related mortality, thus the most pressing need in the field of oncology today is the ability to accurately predict future onset of metastatic disease, ideally at the time of initial diagnosis. As opposed to current practice, what would be desirable is that prognostic, biomarker-based detection of metastatic propensity and heightened risk of cancer recurrence be performed long before overt metastasis has set in. Without such timely information it will be impossible to formulate a rational therapeutic treatment plan to favorably alter the trajectory of disease progression. In order to help inform rational selection of targeted therapeutics, any recurrence/metastasis risk prediction strategy must occur with the paired identification of novel prognostic biomarkers and their underlying molecular regulatory mechanisms that help drive cancer recurrence/metastasis (i.e. recurrence biomarkers). Traditional clinical factors alone (such as TNM staging criteria) are no longer adequately prognostic for this purpose in the current molecular era. FOXC1 is a pivotal transcription factor that has been functionally implicated to drive cancer metastasis and has been demonstrated to be an independent predictor of heightened metastatic risk, at the time of initial diagnosis. In this review, we present our viewpoints on the master regulatory role that FOXC1 plays in mediating cancer stem cell traits that include cellular plasticity, partial EMT, treatment resistance, cancer invasion and cancer migration during cancer progression and metastasis. We also highlight potential therapeutic strategies to target cancers that are, or have evolved to become, “transcriptionally addicted” to FOXC1. The potential role of FOXC1 expression status in predicting the efficacy of these identified therapeutic approaches merits evaluation in clinical trials.

Superior breast cancer metastasis risk stratification using an epithelial-mesenchymal-amoeboid transition gene signature

BACKGROUND

Cancer cells are known to display varying degrees of metastatic propensity, but the molecular basis underlying such heterogeneity remains unclear. Our aims in this study were to (i) elucidate prognostic subtypes in primary tumors based on an epithelial-to-mesenchymal-to-amoeboid transition (EMAT) continuum that captures the heterogeneity of metastatic propensity and (ii) to more comprehensively define biologically informed subtypes predictive of breast cancer metastasis and survival in lymph node-negative (LNN) patients.

METHODS

We constructed a novel metastasis biology-based gene signature (EMAT) derived exclusively from cancer cells induced to undergo either epithelial-to-mesenchymal transition (EMT) or mesenchymal-to-amoeboid transition (MAT) to gauge their metastatic potential. Genome-wide gene expression data obtained from 913 primary tumors of lymph node-negative breast cancer (LNNBC) patients were analyzed. EMAT gene signature-based prognostic stratification of patients was performed to identify biologically relevant subtypes associated with distinct metastatic propensity.

RESULTS

Delineated EMAT subtypes display a biologic range from less stem-like to more stem-like cell states and from less invasive to more invasive modes of cancer progression. Consideration of EMAT subtypes in combination with standard clinical parameters significantly improved survival prediction. EMAT subtypes outperformed prognosis accuracy of receptor or PAM50-based BC intrinsic subtypes even after adjusting for treatment variables in 3 independent, LNNBC cohorts including a treatment-naïve patient cohort.

CONCLUSIONS

EMAT classification is a biologically informed method that provides prognostic information beyond that which can be provided by traditional cancer staging or PAM50 molecular subtype status and may improve metastasis risk assessment in early stage, LNNBC patients, who may otherwise be perceived to be at low metastasis risk.

Endophytic Consortium With Diverse Gene-Regulating Capabilities of Benzylisoquinoline Alkaloids Biosynthetic Pathway Can Enhance Endogenous Morphine Biosynthesis in Papaver somniferum

Secondary metabolite biosynthesis in medicinal plants is multi-step cascade known to be modulated by associated endophytes. While a single endophyte is not able to upregulate all biosynthetic steps, limiting maximum yield achievement. Therefore to compliment the deficient characteristics in an endophyte we tried consortium of endophytes to achieve maximum yield. Here, efforts were made to maximize the in planta morphine yield, using consortium of two endophytes; SM1B (Acinetobacter sp.) upregulating most of the genes of morphine biosynthesis except T6ODM and CODM, and SM3B (Marmoricola sp.) upregulating T6ODM and CODM in alkaloid-less Papaver somniferum cv. Sujata. Consortium-inoculation significantly increased morphine and thebaine content, and also increased the photosynthetic efficiency of poppy plants resulted in increased biomass, capsule weight, and seed yields compared to single-inoculation. The increment in morphine content was due to the modulation of metabolic-flow of key intermediates including reticuline and thebaine, via upregulating pertinent biosynthetic genes and enhanced expression of COR, key gene for morphine biosynthesis. This is the first report demonstrating the endophytic-consortium complimenting the functional deficiency of one endophyte by another for upregulating multiple genes of a metabolic pathway similar to transgenics (overexpressing multiple genes) for obtaining enhanced yield of pharmaceutically important metabolites.

Simple, narrow, and robust atomic frequency reference at 993 nm exploiting the rubidium (Rb) 5S1/2 to 6S1/2 transition using one-color two-photon excitation

We experimentally demonstrate a one-color two-photon transition from the 5S_1/2 ground state to the 6S_1/2 excited state in rubidium (Rb) vapor using a continuous wave laser at 993 nm. The Rb vapor contains both isotopes (⁸⁵Rb and ⁸⁷Rb) in their natural abundances. The electric dipole-allowed transitions are characterized by varying the power and polarization of the excitation laser. Since the optical setup is relatively simple, and the energies of the allowed levels are impervious to stray magnetic fields, this is an attractive choice for a frequency reference at 993 nm, with possible applications in precision measurements and quantum information processing.

Endophytes of Withania somnifera modulate in planta content and the site of withanolide biosynthesis

Tissue specific biosynthesis of secondary metabolites is a distinguished feature of medicinal plants. Withania somnifera, source of pharmaceutically important withanolides biosynthesizes withaferin-A in leaves and withanolide-A in roots. To increase the in planta withanolides production, a sustainable approach needs to be explored. Here, we isolated endophytes from different parts of W. somnifera plants and their promising role in in planta withanolide biosynthesis was established in both in-vivo grown as well in in-vitro raised composite W. somnifera plants. Overall, the fungal endophytes improved photosynthesis, plant growth and biomass, and the root-associated bacterial endophytes enhanced the withanolide content in both in-vivo and in-vitro grown plants by modulating the expression of withanolide biosynthesis genes in leaves and roots. Surprisingly, a few indole-3-acetic acid (IAA)-producing and nitrogen-fixing root-associated endophytes could induce the biosynthesis of withaferin-A in roots by inducing in planta IAA-production and upregulating the expression of withanolide biosynthesis genes especially MEP-pathway genes (DXS and DXR) in roots as well. Results indicate the role of endophytes in modulating the synthesis and site of withanolides production and the selected endophytes can be used for enhancing the in planta withanolide production and enriching roots with pharmaceutically important withaferin-A which is generally absent in roots.

ERα-XPO1 Cross Talk Controls Tamoxifen Sensitivity in Tumors by Altering ERK5 Cellular Localization

Most breast cancer deaths occur in women with recurrent, estrogen receptor (ER)-α(+), metastatic tumors. There is a critical need for therapeutic approaches that include novel, targetable mechanism-based strategies by which ERα (+) tumors can be resensitized to endocrine therapies. The objective of this study was to validate a group of nuclear transport genes as potential biomarkers to predict the risk of endocrine therapy failure and to evaluate the inhibition of XPO1, one of these genes as a novel means to enhance the effectiveness of endocrine therapies. Using advanced statistical methods, we found that expression levels of several of nuclear transport genes including XPO1 were associated with poor survival and predicted recurrence of tamoxifen-treated breast tumors in human breast cancer gene expression data sets. In mechanistic studies we showed that the expression of XPO1 determined the cellular localization of the key signaling proteins and the response to tamoxifen. We demonstrated that combined targeting of XPO1 and ERα in several tamoxifen-resistant cell lines and tumor xenografts with the XPO1 inhibitor, Selinexor, and tamoxifen restored tamoxifen sensitivity and prevented recurrence in vivo. The nuclear transport pathways have not previously been implicated in the development of endocrine resistance, and given the need for better strategies for selecting patients to receive endocrine modulatory reagents and improving therapy response of relapsed ERα(+) tumors, our findings show great promise for uncovering the role these pathways play in reducing cancer recurrences.

Abstract 1812: Targeting nuclear transport pathways to overcome endocrine resistance and recurrence

Currently, around 75% of patients with breast tumors test positive for estrogen receptor alpha (ERa) and are treated with endocrine therapies, such as tamoxifen. One-third of the breast tumors eventually become refractory, reducing the survival rate for affected patients. A combination of alternative endocrine therapies and kinase inhibitors is currently used in such patients. However, after an initial period of therapy response, these tumors relapse in a more aggressive form. Further, the alternative therapies are not optimal in terms of pharmacological properties, are poorly tolerated, and have side-effects that severely decrease quality of life of the patient. Thus, there is a critical need for novel, targetable, mechanism-based therapeutic strategies that 1) re-sensitize ERa (+) tumors to endocrine therapies, and 2) include diagnostic methods to select patients likely to benefit from this approach.

Our objective in this study is to validate a group of nuclear transport genes as biomarkers for endocrine resistance, and to evaluate their inhibition as a novel means to enhance the effectiveness of endocrine therapies. Our central hypothesis is that high expression of these genes in ERa (+) tumors serve as a viable biomarker for risk of endocrine therapy failure. We focused on XPO1, the main nuclear export protein, which exports ERK5 from the nucleus to the cytoplasm and we used selinexor (KPT-330), the inhibitor of XPO1, which is already used in clinical trials for solid and hematological cancers (clinicalTrials.gov). Our experiments show that estradiol induces nuclear localization of ERK5, which otherwise would contribute to increased invasiveness and metastatic potential in the cytoplasm. Selinexor increases ERK5 nuclear localization in tamoxifen resistant breast cancer cell lines. Our hypothesis is that sequestering ERK5 in the cell nucleus and blocking its recycle into the nucleus by selinexor is directly associated with the improved transcriptional response to endocrine therapies. The nuclear export pathways have not previously been implicated in the development of endocrine resistance, and given the need for better strategies for selecting patients to receive endocrine reagents and improving therapy response of relapsed ERa(+) tumors, our findings show high and significant promise for uncovering the role of these pathways and demonstrating their use in reducing cancer recurrences.

Citation Format: Eylem Kulkoyluoglu, Kinga Wrobel, Yiru Chen Zhao, Karen L. Chen, Kadriye Hieronymi, Jamie Holloway, Yosef Landesman, Tania Ray, Partha S. Ray, Alexander E. Lipka, Rebecca L. Smith, Zeynep Madak Erdogan. Targeting nuclear transport pathways to overcome endocrine resistance and recurrence. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1812.

Carotenoid Nanovector for Efficient Therapeutic Gene Knockdown of Transcription Factor FOXC1 in Liver Cancer

Transcription factor FOXC1 has been implicated to play a critical role in hepatocellular carcinoma (HCC) progression, but targeting FOXC1 for therapeutic benefit remains a challenge owing to its location inside the cell nucleus. Herein we report successful therapeutic gene knockdown of transcription factor FOXC1 in liver cancer cells through efficient delivery of siFOXC1 using novel carotenoid functionalized dendritic nanoparticles (CDN). This delivery system also displayed a markedly reduced toxicity profile compared to a standard siRNA transfection agent. We were able to achieve ∼90% FOXC1 knockdown using the CDN-siFOXC1 complex. Additionally, it was found to have ∼18% greater delivery efficiency compared to treatments with particles which have no carotenoid tagging, thereby emphasizing the role of carotenoid mediated cell internalization in the efficient delivery of CDN-siFOXC1 complex in liver cancer cells.

Diagnosis of Basal-Like Breast Cancer Using a FOXC1-Based Assay

BACKGROUND

Diagnosis of basal-like breast cancer (BLBC) remains a bottleneck to conducting effective clinical trials for this aggressive subtype. We postulated that elevated expression of Forkhead Box transcription factor C1 (FOXC1) is a simple and accurate diagnostic biomarker for BLBC.

METHODS

Accuracy of FOXC1 expression in identifying BLBC was compared with the PAM50 gene expression panel in gene expression microarray (GEM) (n = 1992) and quantitative real-time polymerase chain reaction (qRT-PCR) (n = 349) datasets. A FOXC1-based immunohistochemical (IHC) assay was developed and assessed in 96 archival formalin-fixed, paraffin-embedded (FFPE) breast cancer samples that also underwent PAM50 profiling. All statistical tests were two-sided.

RESULTS

A FOXC1-based two-tier assay (IHC +/- qRT-PCR) accurately identified BLBC (AUC = 0.88) in an independent cohort of FFPE samples, validating the accuracy of FOXC1-defined BLBC in GEM (AUC = 0.90) and qRT-PCR (AUC = 0.88) studies, when compared with platform-specific PAM50-defined BLBC. The hazard ratio (HR) for disease-specific survival in patients having FOXC1-defined BLBC was 1.71 (95% CI = 1.31 to 2.23, P < .001), comparable to PAM50 assay-defined BLBC (HR = 1.74, 95% CI = 1.40 to 2.17, P < .001). FOXC1 expression also predicted the development of brain metastasis. Importantly, unlike triple-negative or Core Basal IHC definitions, a FOXC1-based definition is able to identify BLBC in both ER+ and HER2+ patients.

CONCLUSION

A FOXC1-based two-tier assay, by virtue of being rapid, simple, accurate, and cost-effective may emerge as the diagnostic assay of choice for BLBC. Such a test could substantially improve clinical trial enrichment of BLBC patients and accelerate the identification of effective chemotherapeutic options for this aggressive disease.

Abstract P2-06-04: Proteosome inhibitor bortezomib inhibits NFκB and effectively overcomes cancer stem cell escape triggered by Wnt inhibitor therapy in FOXC1+ basal-Like/claudin-low breast cancer

Cancer stem cells (CSCs) are considered to be an important contributing factor towards treatment failure, cancer recurrence, and mortality. CSCs are known to be more enriched in the basal-like and claudin-low subtypes of breast cancer. The Wnt/β catenin signaling pathway is well known as a regulator of embryonic development and stem cell biology, and is prominently active in basal-like and claudin-low breast cancers. We have previously reported that transcription factor FOXC1 plays a critical role in mediating aggressive cell traits in basal-like/claudin-low breast cancer. In this study, we sought to investigate the link between Wnt signaling and FOXC1 and its potential in regulating CSC biology in basal-Like/claudin-low breast cancer. We observed that exposure of the MDA-MB-231 basal-like/claudin-low cell line (low constitutive FOXC1 expressor) to Wnt3a (a canonical Wnt signaling ligand), resulted in increased expression of FOXC1. Reciprocally, overexpression of FOXC1 in MCF10A human mammary epithelial cells led to a pronounced increase in Wnt signaling activity, strongly suggestive of a direct or indirect positive feedback loop between Wnt signaling and FOXC1. More importantly, BT549 and HS578t basal-like/claudin-low cells (high constitutive FOXC1 expressors) proved to be more sensitive to treatment with the Wnt inhibitor ICRT3 as evidenced by decreased cell viability when compared to MCF7 (luminal) or SKBR3 (HER2) breast cancer cell lines. Furthermore the decrease in cell viability appeared to be proportionate to the level of FOXC1 expression. Upon pharmacological inhibition with ICRT3 and biological inhibition with siRNA knockdown of LRP6, (a canonical Wnt signaling cell surface receptor) a decrease in FOXC1 expression level was observed in a dose and time dependent manner. This effect was particularly pronounced in mammosphere cultures enriched for BT549 cancer stem-like cells. Inhibition of Wnt signaling reduced mammosphere formation efficiency of BT549 cells, suggesting that Wnt inhibition targets cancer stem cells (CSCs) in the basal-like/claudin-low breast cancer subtype. More importantly, however, after an initial 4 day incubation period, some cells are observed to persist and later display renewed enhancement of mammosphere formation ability. Profiling of such cells interestingly revealed depletion of FOXC1+ve cells but persistence of cells displaying pronounced up regulation of stereotypical embryonic stem cell Transcription Factors OCT4, SOX2 and NANOG, strongly suggestive of a potential primitive stem cell/quiescent cell state escape mechanism. qRT-PCR based pathway activation analysis revealed marked activation of NFκB signaling in the residual cells that withstood Wnt inhibition. Simultaneous pharmacologic inhibition with Wnt inhibitor ICRT3 and the proteasome inhibitor Bortezomib (known to inhibit NFκB signaling) effectively targeted BT549 cancer stem cells in mammosphere culture and prevented the persistence/emergence of any residual cells. Taken together, our findings suggest that combination therapy approaches are likely required to effectively target breast cancer stem cells.

Citation Format: Partha S Ray, Connie Y Tsai, Tania Ray, Bomy Kim, Tor W Jensen. Proteosome inhibitor bortezomib inhibits NFκB and effectively overcomes cancer stem cell escape triggered by Wnt inhibitor therapy in FOXC1+ basal-Like/claudin-low breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-06-04.

Abstract P1-07-30: FOXC1/FOXA1 transcriptional balance in breast cancer: From acquisition of mesenchymal and stem cell traits to occult lymph node independent breast cancer metastasis

Background: Distant metastatic spread of cancer cells to other organs from the primary site of origin currently constitutes the most significant contributor to cancer-related morbidity and mortality. Epithelial-to-mesenchymal transition (EMT) is a biologic transformation of cancer cells from a non-migratory phenotype to a migratory one, and is thought to initiate the metastatic cascade in cancer. EMT has also been reported to trigger acquisition of stem cell traits in breast cancer. Transcription factor (TF) Forkhead box C1 (FOXC1), strongly associated with the basal-like and claudin-low breast cancer molecular subtypes, is a powerful EMT inducer and is also a marker of stem/progenitor cells. In contrast, TF forkhead box A1 (FOXA1), strongly associated with luminal subtypes, is an EMT repressor and a luminal differentiation marker, thus seemingly exerting reciprocally opposite transcriptional effects to that of FOXC1. We hypothesized that effective EMT program activation status in breast cancer might be better predicted by examining the expression ratio of an EMT inducer and EMT repressor, such as FOXC1/FOXA1, theoretically being more reflective of net transcriptional effect than either component alone. Methods: Herein we utilize RNA-Seq profiling of the HRAS-transformed MCF10A cell series, a well characterized and widely accepted in vitro model of breast cancer progression and metastasis, to correlate measured FOXC1/FOXA1 ratios to dynamic shifts in EMT marker expression in 3D matrigel cultures and to stem cell traits observed in primary and secondary mammosphere suspension cultures. We further test the ability of the FOXC1/FOXA1 expression ratio to predict lymph node independent breast cancer metastasis and death in independent human breast cancer gene expression datasets. Results: RNA-Seq and qRT-PCR profiling confirmed progressive increase in FOXC1/FOXA1 ratio to correlate with a progressive loss of E-cadherin expression and synchronous gain of EMT markers N-cadherin, Fibronectin, and Vimentin. FOXC1/FOXA1 ratio was found to be directly proportional to mammosphere formation efficiency, a surrogate indicator of stem cell enrichment. In patients without any evidence of nodal metastasis, elevated FOXC1/FOXA1 ratio was associated with significantly decreased 10 year Overall Survival (HR 2.58;95%CI 1.39 to 4.80, p = 0.003, 295 patient Van de Vijver dataset), 10 year Disease-specific Survival (HR 1.74;95%CI 1.16 to 2.61, p = 0.008,1992 patient Curtis dataset) and predicted the development of lung metastasis. Conclusion: Elevated FOXC1/FOXA1 expression ratio indicates EMT program activation in breast cancer, and predicts the associated occurrence of lymph-node-independent distant metastasis and death in human patients. These findings may allow for the early (pre-symptomatic) diagnosis of clinically occult (node negative) metastasis by using the FOXC1/FOXA1 ratio as a biomarker of metastasis and permit institution of appropriate therapy earlier than currently possible. The current study improves our understanding of EMT and highlights the importance of future studies geared towards unraveling mechanisms involved in regulating FOXC1 and FOXA1 expression in breast cancer.

Citation Format: Partha S Ray, Tor W Jensen, Tania Ray, Omid Gholamalamdari, Connie Y Tsai, Bomy Kim, Rohit Bhargava, K V Prasanth. FOXC1/FOXA1 transcriptional balance in breast cancer: From acquisition of mesenchymal and stem cell traits to occult lymph node independent breast cancer metastasis [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-07-30.

Interaction of HIPPI with putative promoter sequence of caspase-1 in vitro and in vivo

To investigate the mechanism of increased expression of caspase-1 in Hippi expressing HeLa and Neuro 2A cells, reported earlier, we report here that HIPPI directly interacted with upstream sequence of caspase-1 gene (-700 to +17, 717 bp). Deletion of this 717 bp sequence and further analysis by electrophoretic mobility shift assay and fluorescence quenching revealed that HIPPI interacted with 60 bp (-151 to -92) upstream sequence of caspase-1. We also observed by chromatin immunoprecipitation assay that HIPPI interacted with the 717 bp sequence in vivo. In luciferase assay, when expression of the reporter gene was driven by either 717 bp or 60 bp caspase-1 upstream sequences, luciferase activity was increased in GFP-Hippi expressing HeLa cells in comparison to that obtained with parental HeLa cells with the same constructs. Similar result was obtained in Neuro2A cells with 717 bp caspase-1 upstream sequence. In summary, we showed that HIPPI could interact with the putative promoter sequence of caspase-1 and increased the expression of the downstream gene suggesting that HIPPI could act as transcription regulator.

Intentional puncture of the dural space as an aid to epidural placement in a morbidly obese parturient

OBJECTIVE

In this case report the authors discuss a technique occasionally employed at their institution to aid in identification of the epidural space in morbidly obese parturients.

CASE REPORT

A 29-year-old primagravida, with a body mass index of 90 (155 cm tall, 215 kg) presented for induction of labor. A 27-ga. Sprotte spinal needle was intentionally passed through a Weiss epidural needle and into the subarachnoid space to confirm placement of the Weiss needle in the epidural space. An epidural catheter was then placed which functioned well for labor and subsequent caesarian delivery.

CONCLUSIONS

In selected patients, intentional puncture of the dura can aid in confirmation of the epidural space.

High-throughput approaches to the quantitative analysis of ketoconazole, a potent inhibitor of cytochrome P450 3A4, in human plasma

Ketoconazole, an imidazole-piperazine compound, is an orally active antimycotic agent. In addition, ketoconazole is a specific inhibitor of cytochrome P450 3A4. As about 60% of oxidized drugs are biotransformed by this isoform, the potential effect of a concomitant administration of ketoconazole on drug disposition may be of interest during drug development. The present paper describes three different approaches (methods A, B, and C) to attain high-throughput sample preparation and analysis in the quantification of ketoconazole in human plasma. Method A consisted of acetonitrile precipitation in a 96-well plate, transfer of the supernatant via a Tomtec Quadra 96 Model 320, and subsequent injection onto a 50 x 4.6 mm (i.d.) Develosil Combi-RP-5 column (packed with C30 bonded silica particles). Method B consisted of an identical sample preparation to method A with the exception that a Michrom Magic Bullet(trade mark) column, 2.0 --> 0.50 mm (i.d., tapered bore) x25 mm length, was used. Lastly, in method C, a turbulent-flow chromatography (TurboFlow LC/APCI-MS/MS) module was used for the direct analysis of ketoconazole in human plasma. A Sciex API 3000 was used in methods A and B, while a Micromass Quattro LC was employed in method C. Based on the values obtained for the calibrator (standard) and quality control samples, all three protocols yielded satisfactory accuracy, precision, and reduced manual sample preparation time.

Prophylactic angiotensin II infusion during spinal anesthesia for elective cesarean delivery

BACKGROUND

Angiotensin II may prove useful in treating regional anesthesia-induced hypotension in obstetric patients, because it causes less uterine vasoconstriction than do other vasoconstrictor drugs (such as phenylephrine). This study compared (1) maternal blood pressure and heart rate and (2) fetal status at delivery in parturients given either prophylactic angiotensin II or ephedrine infusion during spinal anesthesia for elective cesarean delivery.

METHODS

Fifty-four women were randomized to receive either angiotensin II or ephedrine infusion intravenously during spinal anesthesia for elective cesarean section delivery. Simultaneous with subarachnoid injection, infusion of angiotensin II (2.5 microg/ml) or ephedrine (5 mg/ml) was initiated at 10 ng x kg(-1) x min(-1) and 50 microg x kg(-1) x min(-1), respectively. The rate of each infusion was adjusted to maintain maternal systolic blood pressure at 90-100% of baseline.

RESULTS

Cumulative vasopressor doses (mean+/-SD) through 10, 20, and 30 min were 150+/-100, 310+/-180, and 500+/-320 ng/kg in the angiotensin group and 480+/-210, 660+/-390, and 790+/-640 microg/kg in the ephedrine group. Maternal heart rate was significantly higher (P < 0.001) during vasopressor infusion in the ephedrine group than in the angiotensin group. Umbilical arterial and venous blood pH and base excess were all significantly higher (P < 0.05) in the angiotensin group than in the ephedrine group.

CONCLUSIONS

Angiotensin II infusion maintained maternal systolic blood pressure during spinal anesthesia without increasing maternal heart rate or causing fetal acidosis.

Effect of 'Compound R' on thermal burn and full-depth wound contracture in fuzzy rats

We evaluated the efficacy of Compound R emulsion on wound contraction in fuzzy rats. While the rats were under anesthesia, two mirror-image burn wounds were inflicted on the depilated back skin of each. Wounds were assigned randomly to treatment or placebo (oil), and the wound-scar areas were measured when they healed. A second set of wounds was created by taking two 6 millimeter punch biopsies from each rat and treated with Compound R or placebo. Under anesthesia, areas of the wound were measured on days 0, 5, 8 and on healing. Mean+/-SE areas for the healed burn wounds were: 151+/-24 mm2 for the treated and 102+/-26 mm2 for the placebo side (paired Student's t test, t=4.21, p=0.0015). Areas for Compound R-treated punch biopsy-induced wounds were significantly larger than placebo treated at each time point (p < 0.01). Results from this study show that Compound R impeded wound contraction.

Syndesmotic screw placement: a biomechanical analysis

At the present time, syndesmotic screw fixation is recommended when there is a tibiofibular diastasis, a Maisonneuve fracture, or syndesmotic instability after fixation of distal tibia-fibula fractures. The aim/purpose of this study was to demonstrate the optimal level of syndesmotic screw placement before creation of a Maisonneuve fracture. Legs of 17 embalmed cadavers underwent knee disarticulation. The legs were then dissected to expose the syndesmosis/interosseous membrane. The paired cadaver legs were tested in two groups. In group I (10 pairs), the left legs were tested without any syndesmotic fixation and the right legs were tested with the syndesmosis fixed at 2.0 cm above the tibiotalar joint. In group II (7 pairs), the syndesmosis in each left leg was fixed at 3.5 cm above the tibiotalar joint and the right leg syndesmosis was fixed at 2.0 cm above the tibiotalar joint. After ligament section and syndesmosis fixation, each leg was then jig mounted with transfixing wires through the proximal tibia and calcaneus. The ankle was placed in neutral with 15 degrees of pronation and a load of 150 pounds and a strain gauge anchored medially and laterally. The proximal tibia was internally rotated while the ankle was held fixed until syndesmotic, bony, or hardware failure occurred. Torsional force, the degree of rotation and the amount of syndesmotic widening were quantitated. Two-tailed t-test comparing no fixation with fixation at 2.0 cm indicated less syndesmotic widening with screw placed at 2.0 cm (P = 0.04). Two-tailed t-test comparing screw fixation at 2.0 cm and 3.5 cm indicated less syndesmotic widening with screw placed at 2.0 cm (P = 0.07). It would seem reasonable to place a syndesmotic screw at 2.0 cm above tibiotalar joint.

Tris-dependent oxidative DNA strand scission during electrophoresis

The DNA of two Streptomyces species contains site-specific labile modifications. During gel electrophoresis the DNA can undergo Tris-dependent strand scission at the positions of these modifications. Our investigations into the nucleolytic activity which reacts with the modifications implicate a peracid derivative of Tris formed at the anode; the kinetics of production and decay of this activity were followed using both a DNA cleavage assay and a reduced methyl viologen assay to measure oxidant. Anode activation could be chemically mimicked by addition of peracetic acid to Tris buffers. We tested the DNA cleavage activity of several other compounds after anode or chemical activation; we used an analogue of Tris lacking a primary amine group and also several reagents known to promote DNA strand cleavage by amine-catalysis at abasic sites. Anode generation of oxidant could be detected for compounds containing either hydroxyl or carboxyl groups. However, DNA cleavage activity correlated with oxidant formation only for those compounds also containing primary amine groups. These results support a mechanism of DNA strand scission at modification sites via concerted peracid-mediated oxidative and amine-catalysed reactions. The novel finding of Tris-dependent formation of a long-lived reactive oxidant at the anode suggests that this compound is unsuited as an electrophoresis buffer for certain biological macromolecules.

Tris-dependent site-specific cleavage of Streptomyces lividans DNA

During conventional gel electrophoresis, Streptomyces lividans DNA undergoes site-specific double-strand cleavage at the positions of closely opposed unstable modifications introduced into the DNA in vivo. We investigated this electrophoretic instability and demonstrated that it was dependent on Tris. Tris buffer was activated at the anode to generate a nucleolytic species; prior to activation, Tris was not able to cleave the DNA. The nucleolytic species was shown to react with thiourea, which could thus protect the DNA from strand cleavage. Non-degradative electrophoresis of the DNA could also be achieved in an alternative buffer such as Hepes.

Subinhibitory concentrations of tetracycline alter fibrinogen binding by Bacteroides intermedius

Previous studies from our laboratory have shown that a strain of Bacteroides intermedius, VPI 8944, an organism isolated originally from a patient with acute necrotizing ulcerative gingivitis, binds human fibrinogen rapidly, reversibly, specifically, saturably, and with high affinity (M.S. Lantz, L.M. Switalski, K.S. Kornman, and M. Höök, J. Bacteriol. 163:623-628, 1985). We examined the effect of growth in subinhibitory levels (sub-MICs) of tetracycline on fibrinogen binding by these bacteria and found concentration-dependent inhibition of fibrinogen binding by bacteria grown in the presence of tetracycline over the range of tetracycline concentrations from 1/64 to 1/8 the MIC. Analysis of the binding data suggests that bacteria grown in the presence of sub-MICs of tetracycline bind fewer fibrinogen molecules per cell than do bacteria grown in the absence of the drug. If fibrinogen-mediated adherence is important in the establishment B. intermedius in periodontal lesions and lesions of acute necrotizing ulcerative gingivitis, then tetracycline may be effective in disrupting establishment of these organisms at concentrations well below those required to achieve a bacteriostatic effect.

Abnormalities in monoamine levels in the central nervous system of the genetically epilepsy-prone rat

Norepinephrine, dopamine, and 5-hydroxytryptamine concentrations were determined in the central nervous systems of genetically epilepsy-prone rats (GEPR) and in control rats. Norepinephrine concentrations were abnormal in all major areas of the central nervous system of the GEPR, with decrements existing in the telencephalon, hypothalamus-thalamus, midbrain, pons-medulla and spinal cord. An increment in the concentration of this neurotransmitter existed in the cerebellum. Dopamine concentrations were normal in all areas of the GEPR brain. Abnormalities in 5-hydroxytryptamine concentrations were also present in the GEPR. They were exclusively decrements and occurred in the telencephalon, hypothalamus-thalamus, midbrain, and pons medulla. Concentrations of this neurotransmitter were normal in the cerebellum and spinal cord. Coupled with our earlier pharmacologic data, these observations support our concept that noradrenergic and/or 5-hydroxytryptaminergic decrements are etiologically important in seizure susceptibility in the GEPR. The lack of abnormalities in brain dopamine concentrations strengthens our hypothesis that dopaminergic transmission does not regulate seizure susceptibility in this model.