Vein-first vs. artery-first robotic lobectomy outcomes in non-small cell lung cancer

Background

Data remains limited as to whether the order of pulmonary vessel division during performance of a lobectomy for non-small cell lung cancer (NSCLC) affects survival outcomes. Some authors have suggested that ligation of the pulmonary veins should be conducted first in order to minimize the spread of tumor cells secondary to manipulation of the lung. This study examines whether there is a difference in outcomes between patients who undergo robotic lobectomies for NSCLC using a vein-first (V-first) vs. artery-first (A-first) technique.

Methods

A retrospective review of electronic medical record data was performed for patients who underwent robotic lobectomies from January 2013 to May 2019. Patients were separated into two groups based on the sequence in which the pulmonary vessels were divided: V-first or A-first. Baseline characteristics and postoperative events were recorded and compared between groups using Chi-squared and Student's t-tests. Kaplan-Meier survival curves for overall and recurrence-free survival were constructed and compared with log-rank tests.

Results

A total of 374 patients were identified: 94 V-first and 280 A-first patients. There was no significant difference between the V-first and A-first groups with regards to postoperative complications, length of stay, recurrence-free survival, or overall survival.

Conclusions

Our study suggests that choosing a V-first vs. A-first technique for a robotic lobectomy does not significantly impact overall survival or cancer recurrence for patients with NSCLC. Further studies are needed to evaluate whether the order of pulmonary vessel resection affects outcomes for patients with NSCLC.

MiR-199a-5p Decreases Esophageal Cancer Cell Proliferation Partially through Repression of Jun-B

MicroRNA (miR)-199a-5p has been shown to function as a tumor suppressor in some malignancies but its role in esophageal cancer is poorly understood. To further explore its role in esophageal cancer, we sought to investigate the interaction between miR-199a-5p and Jun-B, an important component of the AP1 transcription factor, which contains a potential binding site for miR-199a-5p in its mRNA. We found that levels of miR-199a-5p are reduced in both human esophageal cancer specimens and in multiple esophageal cancer cell lines compared to esophageal epithelial cells. Jun-B expression is correspondingly elevated in these tumor specimens and in several cell lines compared to esophageal epithelial cells. Jun-B mRNA expression and stability, as well as protein expression, are markedly decreased following miR-199a-5p overexpression. A direct interaction between miR-199a-5p and Jun-B mRNA was confirmed by a biotinylated RNA-pull down assay and luciferase reporter constructs. Either forced expression of miR-199a-5p or Jun-B silencing led to a significant decrease in cellular proliferation as well as in AP-1 promoter activity. Our results provide evidence that miR-199a-5p functions as a tumor suppressor in esophageal cancer cells by regulating cellular proliferation, partially through repression of Jun B.

Correction: Zare et al. Encapsulation of miRNA and siRNA into Nanomaterials for Cancer Therapeutics. Pharmaceutics 2022, 14, 1620

In the original publication [...].

MiR-214-3p targets Ras-related protein 14 (RAB14) to inhibit cellular migration and invasion in esophageal Cancer cells

BACKGROUND

MicroRNA (miR)-214-3p is emerging as an important tumor suppressor in esophageal cancer. In this study, we examined the interaction between miR-214-3p and RAB14, a membrane trafficking protein shown to exert oncogenic functions in other malignancies, in esophageal cancer cells.

METHODS

Studies were performed in a human esophageal epithelial cell line and a panel of esophageal cancer cell lines, as well in human specimens. MiR-214-3p expression was measured by digital PCR. Biotinylated RNA pull-down and luciferase reporter assays assessed binding. The xCELLigence RTCA system measured cell migration and invasion in real time. A lentiviral expression vector was used to create an esophageal cancer cell line stably expressing miR-214-3p.

RESULTS

MiR-214-3p expression was decreased in esophageal cancer cell lines and human specimens compared to non-malignant controls. RAB14 mRNA stability and protein expression were decreased following miR-214-3p overexpression. Binding between miR-214-3p and RAB14 mRNA was observed. Either forced expression of miR-214-3p or RAB14 silencing led to a marked decrease in cellular migration and invasion. Esophageal cancer cells stably expressing miR-214-3p demonstrated decreased growth in a subcutaneous murine model.

CONCLUSIONS

These results further support the tumor-suppressive role of miR-214-3p in esophageal cancer cells by demonstrating its ability to regulate RAB14 expression.

Abstract B33: Tumor-stromal response to immune checkpoint blockade within patient tissue derived three-dimensional lung tumor models

The tumor microenvironment is a key regulator of tumor biology and response to therapeutic intervention, with intercellular communication between tumor and stromal cells regulating growth and progression. While two dimensional cultures are commonly utilized for in vitro preclinical studies, they do not recapitulate the tissue microenvironment or three dimensional tissue architecture. Herein, we utilize tissue engineering strategies and patient-derived specimen to develop ex vivo non-small cell lung tumor models. These models allow for evaluation of tumor-stromal interactions and response to immune directed therapies while keeping the native tissue microenvironment intact. For this study, tumor models were generated utilizing remnant lung tumor specimen from consented patients undergoing surgical tumor resection. 5 mm diameter tissue cores were placed in a volume of extracellular matrix within a perfusion bioreactor platform, and through-channels were generated to provide nutrient circulation during ex vivo culture. Spatial profiling using the Nanostring GeoMx platform, multiplex cytokine analysis, histologic and flow cytometric analyses were performed following culture. Primary human tumor specimens cultured ex vivo maintain histologic architecture and representative cell populations following 14 days culture. Tissues treated with an anti-programmed cell death protein 1 (PD-1) blocking antibody showed reduced IL-6 (380.8 ±133.9 pg/mL) levels within the circulating media when compared to IgG control treated tissues (1119 ±382.9 pg/mL, p=0.08). Spatial profiling showed increased proportions of dividing T cells (2.27 ± 1.02 IgG vs. 8.28 ± 1.171 anti-PD-1; p=0.02) and CD8+ memory T cells (0.09 ± 0.09 IgG vs. 1.74 ± 0.64 anti-PD-1; p=0.04) and a trend towards more natural killer cells (3.88 ± 0.73 IgG vs. 6.56 ± 3.14 anti-PD-1; p=0.067), along with decreased proportions of macrophages (14.33 ± 2.16 IgG vs. 6.44 ± 0.59 anti-PD-1; p=0.004) near the tumor in tissues treated with anti-PD-1 when compared to control. Additionally, genes within the tumor immune signature associated with programmed cell death ligand 1 suppression, anti-tumor cytotoxicity and T cell response, including CXCR6, CCL3, NKG7, CMKLR1, CD27 & PSMB10, were upregulated and genes associated with immune suppression, including IDO and HLA-E, were downregulated with anti-PD-1 treatment when compared to IgG control. Moving forward, this platform will allow for extensive characterization of tumor-stromal interactions, response to therapeutic intervention, and therapeutic resistance in a patient specific manner. Funding: Nanostring DSP Cancer Transcriptome Atlas Award; 1R21 CA263365-01A1; Respiratory Health Association Lung Cancer Award (RHA2022-01-LC).

Citation Format: Kayla F. Goliwas, Anthony M. Wood, Young-il Kim, Joel L. Berry, James M. Donahue, Jessy S. Deshane. Tumor-stromal response to immune checkpoint blockade within patient tissue derived three-dimensional lung tumor models [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy; 2022 Oct 21-24; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(12 Suppl):Abstract nr B33.

Encapsulation of miRNA and siRNA into Nanomaterials for Cancer Therapeutics

Globally, cancer is amongst the most deadly diseases due to the low efficiency of the conventional and obsolete chemotherapeutic methodologies and their many downsides. The poor aqueous solubility of most anticancer medications and their low biocompatibility make them ineligible candidates for the design of delivery systems. A significant drawback associated with chemotherapy is that there are no advanced solutions to multidrug resistance, which poses a major obstacle in cancer management. Since RNA interference (RNAi) can repress the expression of genes, it is viewed as a novel tool for advanced drug delivery. this is being explored as a promising drug targeting strategy for the treatment of multiple diseases, including cancer. However, there are many obstructions that hinder the clinical uses of siRNA drugs due to their low permeation into cells, off-target impacts, and possible unwanted immune responses under physiological circumstances. Thus, in this article, we review the design measures for siRNA conveyance frameworks and potential siRNA and miRNA drug delivery systems for malignant growth treatment, including the use of liposomes, dendrimers, and micelle-based nanovectors and functional polymer-drug delivery systems. This article sums up the advancements and challenges in the use of nanocarriers for siRNA delivery and remarkably centers around the most critical modification strategies for nanocarriers to build multifunctional siRNA and miRNA delivery vectors. In short, we hope this review will throw light on the dark areas of RNA interference, which will further open novel research arenas in the development of RNAi drugs for cancer.

Abstract 1486: MicroRNA (miR)199a-5p targets JUN-B to decrease cell proliferation in esophageal cancer cells

Objectives: MiR-199a-5p has been shown to be downregulated in multiple malignancies and function as a tumor suppressor. We have previously demonstrated that miR-199a-5p is markedly downregulated in esophageal cancer cell lines compared to esophageal epithelial cells. In several miR-target sequence analysis programs, miR-199a-5p is predicted to bind JUN-B mRNA with high affinity. JUN-B is an important component of the AP1 transcription factor. The objective of this study was to determine expression of JUN-B in esophageal cancer cells as well as to investigate the interaction between miR-199a-5p and JUNB in these cells and to characterize the functional implications of this interaction.

Methods: Studies were performed in human esophageal epithelial (hESO) cells and in TE7, SK-GT-4 and OE21 human esophageal cancer cells. Expression of miR-199a-5p and JUNB mRNA in these cell lines was measured by real-time PCR. JUNB protein expression levels were examined by Western blot. Function of miR-199a-5p was tested through its overexpression and silencing. Cellular proliferation was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

Results: Levels of miR-199a-5p in TE7, SK-GT-4, and OE21 esophageal cancer cells are markedly reduced compared to hESO cells. JUN-B mRNA and protein expression are correspondingly elevated in these cells compared to hESO cells. JUN-B mRNA and protein expression levels were decreased following miR-199a-5p overexpression in TE7, SK-GT-4 and OE21 cells. In reciprocal experiments, silencing miR-199a-5p in hESO cells resulted in increased JUN-B protein and mRNA levels. Forced expression of miR-199a-5p in TE7, SK-GT-4 and OE21 cells led to a marked decrease in cellular proliferation.

Conclusions: MiR-199a-5p expression is significantly reduced in TE7, SK-GT-4, and OE21 esophageal cancer cells relative to hESO cells. Forced expression of miR-199a-5p results in significantly decreased JUN-B mRNA and protein expression in these cells, leading to decreased cellular proliferation. These results add our understanding of the roles by which miR-199a-5p functions as a tumor suppressor in esophageal cancer cells. Further studies will investigate the association of miR-199a-5p with JUN-B mRNA using biotinylated RNA pull-down and luciferase reporter assays, in addition to determining the effect of Jun-B downregulation on AP1 promoter activity.

Citation Format: Pornima Phatak, Mohan E. Tulapurkar, James M. Donahue. MicroRNA (miR)199a-5p targets JUN-B to decrease cell proliferation in esophageal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1486.

Evolution of Technique and Results Following Permanent Open Repair for Pectus Deformities

Objective

Open correction of pectus deformities has evolved since its origin. We performed a Ravitch type repair using a permanent titanium plate fixed with screws and describe the procedure with outcomes after our modifications.

Methods

A retrospective review of 61 pectus excavatum and pectus carinatum cases from August 2013 to April 2021 was performed. Data were extracted from medical records and reported. In January 2016, we began administering satisfaction surveys at the 6-month postoperative visit; results are reported.

Results

The mean age of our cohort was 24.5 years; 43 (70%) were male. Fifty-four underwent pectus excavatum repair, 6 pectus carinatum repair, and 1 mixed repair. Median Haller index was 3.8. Mean operative duration was 98 minutes; mean blood loss was 116.4 mL. Median chest tube duration was 5.0 days; median hospital stay was 4 days. Reexploration for bleeding was 30% in the first 10 patients. Protocol changes including postponing chemical deep vein thrombosis prophylaxis, using intraoperative hemostatic agents, and using shorter implantation screws decreased this to 0% for the remaining cases. The most frequent complication was urinary retention (21.3%). Postoperative surveys were completed for 37 of 50 patients. Seventy-five percent reported health improved, 65% reported exercise capacity improved, 75% reported breathing improved, and 59% reported chest pain improved. Self-esteem improved from 6.6 ± 2.5 (of 10) before surgery to 8.2 ± 2.1 after surgery. Ninety percent were satisfied and 86% would have the operation again.

Conclusions

Ravitch type repair with permanent titanium plate fixation is a safe and effective procedure for correction of pectus excavatum and carinatum. Most patients experience improvement in preoperative symptoms.

Local SARS-CoV-2 peptide-specific Immune Responses in Convalescent and Uninfected Human Lung Tissue Models

Multi-specific and long-lasting T cell immunity have been recognized as indicators for long term protection against pathogens including the novel coronavirus SARS-CoV-2, the causative agent of the COVID-19 pandemic. Functional significance of peripheral memory T cell subsets in COVID-19 convalescents (CONV) are beginning to be appreciated; but little is known about lung resident memory T cell (lung TRM) responses and their role in limiting the severity of SARS-CoV-2 infection. Here, we utilize a perfusion three dimensional (3D) human lung tissue model and identify pre-existing local T cell immunity against SARS-CoV-2 spike protein and structural antigens in the lung tissues. We report ex vivo maintenance of functional multi-specific IFN-γ secreting lung TRM in CONV and their induction in lung tissues of vaccinated CONV. Importantly, we identify SARS-CoV-2 spike peptide-responding B cells in lung tissues of CONV in ex vivo 3D-tissue models. Our study highlights a balanced and local anti-viral immune response in the lung and persistent induction of TRM cells as an essential component for future protection against SARS-CoV-2 infection. Further, our data suggest that inclusion of multiple viral antigens in vaccine approaches may broaden the functional profile of memory T cells to combat the severity of coronavirus infection.

MicroRNA-141-3p regulates cellular proliferation, migration, and invasion in esophageal cancer by targeting tuberous sclerosis complex 1

MicroRNA (miR)-141-3p, which functions as an oncogene in multiple malignancies, has been shown to be highly overexpressed in esophageal cancer cells in our previous work. miR-141-3p is predicted to bind the messenger RNA (mRNA) of tuberous sclerosis complex 1 (TSC1), a tumor suppressor, with high affinity. In this study, we investigated the expression and functional interaction between miR-141-3p and TSC1 in esophageal cancer cells. Experiments were conducted in four esophageal cancer lines and in tumor cells isolated from human esophageal cancer specimens by laser capture microdissection. miR-141-3p expression was measured by real time and droplet digital PCR. Biotinylated RNA pull-down and luciferase reporter assays were used to assess binding. miR-141-3p function was tested by assessing proliferation, migration, invasion, and induction of autophagy following its silencing. We found that miR-141-3p levels were increased in TE7, OE33, and TE10 esophageal cancer cells compared to FLO-1 cells, with similar heterogeneity observed in human esophageal cancer specimens. Silencing of miR-141-3p led to increased TSC1 protein expression in these cells and was associated with increased TSC1 translation. Binding studies reveal that miR-141-3p binds to each of the predicted binding sites in the 3'-untranslated region of TSC1 mRNA. Following miR-141-3p silencing, TE7, OE33, and TE10 cells exhibited decreased proliferation, migration, and invasion, as well as enhanced autophagy. Importantly, these phenotypic effects were replicated by overexpression of TSC1 alone in these cells. Our results indicate that miR-141-3p functions in an oncogenic capacity in a subset of esophageal cancer cells, in part by suppressing TSC1 expression.

Abstract B23: Engineered three-dimensional lung tumor mimics maintain tissue heterogeneity allowing for investigation of tumor-stromal interactions

The tumor microenvironment is a key regulator of tumor biology and response to therapeutic intervention, with intercellular communication between tumor and stromal cells known to regulate growth and progression. While two-dimensional cell culture is the most common method utilized for in vitro preclinical studies, it creates an artificial environment that does not take into account critical tissue components, including the tissue microenvironment (i.e., matrix proteins and stromal cell populations) and the three-dimensional tissue architecture/dimensionality. Recently, in vitro engineered tissues have been implemented as surrogates of human pathophysiology in biomedical and pharmaceutical research. Herein we utilize tissue engineering strategies to develop in vitro non-small cell lung tumor mimics that include key tissue components, including matrix proteins and stromal cell populations, utilizing patient-derived specimen. With the inclusion of stromal cell populations, these tumor mimics allow for evaluation of tumor-stromal interactions and could be utilized to determine the impact of these interactions on therapeutic response. Engineered tumor mimics were generated utilizing freshly isolated lung tumor specimen from consented patients undergoing surgical tumor resection. 5-mm-diameter tissue cores were produced and placed in a volume of extracellular matrix (ECM) within the bioreactor platform and maintained via a closed perfusion platform to provide nutrient circulation. Histologic and flow cytometric analyses were performed to evaluate cellular heterogeneity within the tumor mimics following culture. Primary human lung tumor specimens cultured ex vivo in the engineered tumor mimic platform maintain histologic architecture and representative cell populations, including endothelial cells (CD31+,10.46%), epithelial cells (EpCAM+,25.15%), fibroblasts (CD90+, 7.23%), CD8+ T cells (CD3+CD8+, 2.95%), and macrophages (CD14+CD64+CD11b+, 9.25%) following 14 days’ culture. Additionally, a tumor-promotive microenvironment is supported by this platform with maintenance of monocytic and granulocytic myeloid-derived suppressor cells (8.59% and 0.83 %, respectively) and tumor-promotive macrophages (M2 like, 81.3% of macrophages). Furthermore, the hypoxic biochemical microenvironment is recapitulated with carbonic anhydrase 9-positive cell populations maintained during culture. Moving forward, this platform will allow for extensive characterization of tumor-stromal interactions, response to therapeutic intervention, and therapeutic resistance in a patient-specific manner.

Citation Format: Kayla F. Goliwas, Yong Wang, Joel L. Berry, Victor J. Thannickal, James M. Donahue, Jessy S. Deshane. Engineered three-dimensional lung tumor mimics maintain tissue heterogeneity allowing for investigation of tumor-stromal interactions [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B23.

MiR-199a-3p decreases esophageal cancer cell proliferation by targeting p21 activated kinase 4

Although microRNA (miR) 199a-3p functions as a tumor suppressor in multiple malignancies, its expression and role in esophageal cancer have not been studied. Based on our previous observation that miR-199a-3p is markedly downregulated in esophageal cancer cell lines relative to esophageal epithelial cells, we examined the function of miR-199a-3p in these cells. MiR-199a-3p is predicted to bind with high affinity to the mRNA of p21 activated kinase 4 (PAK4). This kinase has been shown to be overexpressed in several malignancies and to modulate proliferation and motility. The current study is designed to determine whether miR-199a-3p regulates the expression of PAK4 in esophageal cancer cells and to understand the functional consequences of this interaction. Herein, we demonstrate reduced expression of miR-199a-3p in human esophageal cancer specimens and cell lines compared to esophageal epithelial cells, with associated increased expression of PAK4. Forced expression of miR-199a-3p decreases expression of PAK4 in esophageal cancer cell lines. Mechanistic studies reveal that miR-199a-3p binds to the 3'UTR of PAK4 mRNA. This interaction results in reduced levels of PAK4 mRNA due to decreased mRNA stability. Downregulation of PAK4 leads to decreased cyclin D1 (CD1) transcription and protein expression, resulting in markedly impaired cellular proliferation. When PAK4 expression is rescued, both CD1 transcription and protein return to baseline levels. Our results show that miR-199a-3p functions as a tumor suppressor in esophageal cancer cells through repression of PAK4. These findings suggest that both miR-199a-3p and PAK4 may be novel therapeutic targets in the treatment of esophageal cancer.

Implications of Pathologic Complete Response Beyond Mediastinal Nodal Clearance With High-Dose Neoadjuvant Chemoradiation Therapy in Locally Advanced, Non-Small Cell Lung Cancer

PURPOSE

To determine, in a retrospective analysis of a large cohort of stage III non-small cell lung cancer patients treated with curative intent at our institution, whether having a pathologic complete response (pCR) influenced overall survival (OS) or freedom from recurrence (FFR) in patients who underwent definitive (≥60 Gy) neoadjuvant doses of chemoradiation (CRT).

METHODS AND MATERIALS

At our institution, 355 patients with locally advanced non-small cell lung cancer were treated with curative intent with definitive CRT (January 2000-December 2013), of whom 111 underwent mediastinal reassessment for possible surgical resection. Ultimately 88 patients received trimodality therapy. Chi-squared analysis was used to compare categorical variables. The Kaplan-Meier analysis was performed to estimate OS and FFR, with Cox regression used to determine the absolute hazards.

RESULTS

Using high-dose neoadjuvant CRT, we observed a mediastinal nodal clearance (MNC) rate of 74% (82 of 111 patients) and pCR rate of 48% (37 of 77 patients). With a median follow-up of 34.2 months (range, 3-177 months), MNC resulted in improved OS and FFR on both univariate (OS: hazard ratio [HR] 0.455, 95% confidence interval [CI] 0.272-0.763, P = .004; FFR: HR 0.426, 95% CI 0.250-0.726, P = .002) and multivariate analysis (OS: HR 0.460, 95% CI 0.239-0.699, P = .001; FFR: HR 0.455, 95% CI 0.266-0.778, P = .004). However, pCR did not independently impact OS (P = .918) or FFR (P = .474).

CONCLUSIONS

Mediastinal nodal clearance after CRT continues to be predictive of improved survival for patients undergoing trimodality therapy. However, a pCR at both the primary and mediastinum did not further improve survival outcomes. Future therapies should focus on improving MNC to encourage more frequent use of surgery and might justify use of preoperative CRT over chemotherapy alone.

Abstract B089: MicroRNA (miR) 214-3p targets ras-related protein14 (RAB14) to inhibit cell migration and invasion in esophageal cancer cells

Objectives: MiR-214-3p acts as a tumor suppressor in various malignancies. We have previously shown that miR-214-3p is markedly downregulated in esophageal cancer cell lines compared to esophageal epithelial cells and its downregulation contributes to chemoresistance in esophageal cancer cells. In several miR-target sequence analysis programs, miR-214-3p is predicted to bind RAB14 mRNA with high affinity. RAB14 is a member of the ras-associated binding protein family of low molecular mass GTPases that are involved in membrane trafficking. Its role in cancer is not well known. The objective of this study was to determine expression of RAB14 in esophageal cancer cells as well as to investigate the interaction between miR-214-3p and RAB14 in these cells and to characterize the functional implications of this interaction. Methods: Studies were performed in human esophageal epithelial (hESO) cells and in FLO1, SKGT4, and TE7 human esophageal cancer cells. Expression of miR-214-3p and RAB14 mRNA in these cell lines was measured by real-time PCR. RAB14 protein expression levels were examined by Western blot. Function of miR-214-3p was tested through its overexpression and silencing. Association of miR-214-3p with RAB14 mRNA was established using a biotinylated RNA pull-down assay and was confirmed by luciferase reporter assay. Cellular proliferation was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. xCELLigence RTCA system was used to access cell migration and invasion in real time. Results: Levels of miR-214-3p in FLO1, SKGT4, and TE7 esophageal cancer cells are markedly reduced compared to hESO cells. RAB14 mRNA and protein expression are correspondingly elevated in these cells compared to hESO cells. RAB14 mRNA and protein expression levels decreased in a time-dependent manner following miR-214-3p overexpression in FLO1, SKGT4, and TE7 cells. In reciprocal experiments, silencing miR-214-3p in hESO cells resulted in increased RAB14 mRNA and protein levels. Direct interaction of miR-214-3p and RAB14 mRNA was confirmed by biotinylated RNA-pull down assay and luciferase reporter construct. The stability of RAB14 mRNA is decreased following ectopic expression of miR-214-3p in FLO1 cells. Forced expression of miR-214-3p in FLO1 and SKGT4 cells led to a marked decrease in cellular proliferation, migration, and invasion. Conclusions: MiR-214-3p expression is significantly reduced in FLO1, SKGT4, and TE7 esophageal cancer cells relative to hESO cells. MiR-214-3p directly binds and destabilizes RAB14 mRNA. Forced expression of miR-214-3p results in significantly decreased RAB14 mRNA and protein expression, leading to decreased cellular proliferation, migration, and invasion in esophageal cancer cells. These results add to the roles by which miR-214-3p functions as a tumor suppressor in esophageal cancer cells.

Citation Format: Pornima Phatak, Jaladanki N. Rao, Carol B. Fowler, Douglas J. Turner, Jian-Ying Wang, James M. Donahue. MicroRNA (miR) 214-3p targets ras-related protein14 (RAB14) to inhibit cell migration and invasion in esophageal cancer cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B089.

Biotinylated Micro-RNA Pull Down Assay for Identifying miRNA Targets

microRNA (miRNA) directly associates with its target transcripts (mRNA). This protocol describes a method for detection of direct interaction between miRNA and mRNA. The result of interaction helps screening the specific target mRNAs for a miRNA.

Abstract A37: Overexpression of microRNA (miR) 199a-3p reduces proliferation through the induction of G2/M arrest in esophageal cancer cells by targeting cyclin D1

Objectives: Downregulation of miR-199a-3p has been demonstrated in several malignancies. A potential role of miR-199a-3p as a tumor suppressor has been postulated based on its ability to regulate targets involved in proliferation, apoptosis, and migration. Using miR array analysis, we have previously shown that miR-199a-3p is one of the most markedly downregulated miRs in esophageal cancer cell lines compared to esophageal epithelial cells. To date, no information exists on the role of miR-199a-3p in esophageal cancer cells. In several miR-target sequence analysis programs, miR-199a-3p is predicted to bind cyclin D1 mRNA with high affinity. The objective of this study was to determine expression of cyclin D1 in esophageal cancer cells and to investigate the interaction between miR-199a-3p and cyclin D1 in these cells and to characterize the functional implications of this interaction.

Methods: Studies were conducted in human esophageal epithelial (hESO) cells and in TE7 human squamous esophageal cancer cells. Levels of cyclin D1 protein expression were assessed by Western blot. Expression of miR-199a-3p and cyclin D1 mRNA in these cell lines was measured by real-time PCR. MiR-199a-3p function was tested through its overexpression and silencing. Binding of miR-199a-3p to cyclin D1 mRNA was examined using a biotinylated RNA pull-down assay. Cellular proliferation was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle progression was determined by FACS analysis.

Results: Levels of miR-199a-3p in TE7 esophageal cancer cells are reduced by more than 3 log-fold, as compared to hESO cells. Cyclin D1 protein expression is markedly elevated in TE7 cells compared to hESO cells. Cyclin D1 mRNA and protein expression levels decreased in a time-dependent manner following miR-199a-3p overexpression in TE7 cells. In reciprocal experiments, silencing miR-199a-3p in hESO cells resulted in increased cyclin D1 mRNA and protein levels. Binding of miR-199a-3p to cyclin D1 mRNA was confirmed by biotinylated RNA-pull down assay. Forced expression of miR-199a-3p in TE7 cells led to a marked decrease in cellular proliferation resulting from the induction of G2/M arrest.

Conclusions: MiR-199a-3p expression is significantly reduced in TE7 esophageal cancer cells relative to hESO cells. MiR-199a-3p directly binds cyclin D1 mRNA, leading to its destabilization and a marked decreased in cyclin D1 protein expression. This interaction results in decreased cellular proliferation through the induction of G2/M arrest. These results suggest that the loss of miR-199a-3p in esophageal epithelial cells may be an important event in esophageal carcinogenesis.

Citation Format: Pornima Phatak, Kimberly Byrnes, Jaladanki N. Rao, Douglas J. Turner, Jian Y. Wang, James M. Donahue. Overexpression of microRNA (miR) 199a-3p reduces proliferation through the induction of G2/M arrest in esophageal cancer cells by targeting cyclin D1. [abstract]. In: Proceedings of the AACR Special Conference on Noncoding RNAs and Cancer: Mechanisms to Medicines ; 2015 Dec 4-7; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2016;76(6 Suppl):Abstract nr A37.

Overexpression of miR-199a-5p decreases esophageal cancer cell proliferation through repression of mitogen-activated protein kinase kinase kinase-11 (MAP3K11)

Studies examining the oncogenic or tumor suppressive functions of dysregulated microRNAs (miRs) in cancer cells may also identify novel miR targets, which can themselves serve as therapeutic targets. Using array analysis, we have previously determined that miR-199a-5p was the most downregulated miR in two esophageal cancer cell lines compared to esophageal epithelial cells. MiR-199a-5p is predicted to bind mitogen-activated protein kinase kinase kinase 11 (MAP3K11) mRNA with high affinity. In this study, we observed that MAP3K11 is markedly overexpressed in esophageal cancer cell lines. Forced expression of miR-199a-5p in these cells leads to a decrease in the mRNA and protein levels of MAP3K11, due to decreased MAP3K11 mRNA stability. A direct binding interaction between miR-199a-5p and MAP3K11 mRNA is demonstrated using biotin pull-down assays and heterologous luciferase reporter constructs and confirmed by mutational analysis. Finally, forced expression of miR-199a-5p decreases proliferation of esophageal cancer cells by inducing G2/M arrest. This effect is mediated, in part, by decreased transcription of cyclin D1, due to reduced MAP3K11-mediated phosphorylation of c-Jun. These findings suggest that miR-199a-5p acts as a tumor suppressor in esophageal cancer cells and that its downregulation contributes to enhanced cellular proliferation by targeting MAP3K11.

Multiple specificities of immunoglobulin M in equine fetuses infected with Leptospira interrogans indicate a competent immune response

REASONS FOR PERFORMING STUDY

Foals of mares infected with Leptospira interrogans serovar Pomona type kennewicki (Lk) may be aborted/stillborn or delivered as healthy foals. Is fetal survival explained in part by the immune response of the fetus to Leptospira antigens?

OBJECTIVES

To describe an outbreak of Leptospira abortion in which infected mares delivered dead/sick or normal foals and determine specificities of antibody in a collection of 54 fetuses from similar outbreaks.

STUDY DESIGN

Outbreak investigation in combination with a case-control study of a larger set of samples from aborted fetuses.

METHODS

Serology and polymerase chain reaction (PCR) on urine and amniotic fluids were used to diagnose infection during an outbreak of Leptospira abortion. Specificities of immunoglobulin (Ig)M, IgGa and IgGb for recombinant proteins of Lk in archived fluids of fetuses from similar outbreaks were compared by ELISA with those of fluids of fetuses not infected with Leptospira spp.

RESULTS

Five fetuses of 11 infected mares in an outbreak survived in utero in the presence of persistent placental infection and were healthy at foaling. Fetuses of 6 mares in the outbreak were aborted or died soon after birth. Significantly greater (P<0.05) IgM reactivity with all recombinant proteins and with Lk sonicate was observed in 54 archived fluids from Leptospira infected fetuses than in fluids of 30 of non-Leptospira infected fetuses. Low levels of IgGa and IgGb specific for LipL32 and Lk sonicate and traces of LigA and Hsp15 specific IgGa were detected in a minority of archived fluids from Leptospira infected fetuses.

CONCLUSION

Although mainly mediated by IgM, a high level of immune competence in aborted fetuses was evidenced by the multiplicity of Leptospira proteins targeted. This is likely to contribute to survival of foals in mares with evidence of placental infection at foaling as detailed in a typical outbreak.

Competition between RNA-binding proteins CELF1 and HuR modulates MYC translation and intestinal epithelium renewal

The mammalian intestinal epithelium is one of the most rapidly self-renewing tissues in the body, and its integrity is preserved through strict regulation. The RNA-binding protein (RBP) ELAV-like family member 1 (CELF1), also referred to as CUG-binding protein 1 (CUGBP1), regulates the stability and translation of target mRNAs and is implicated in many aspects of cellular physiology. We show that CELF1 competes with the RBP HuR to modulate MYC translation and regulates intestinal epithelial homeostasis. Growth inhibition of the small intestinal mucosa by fasting in mice was associated with increased CELF1/Myc mRNA association and decreased MYC expression. At the molecular level, CELF1 was found to bind the 3'-untranslated region (UTR) of Myc mRNA and repressed MYC translation without affecting total Myc mRNA levels. HuR interacted with the same Myc 3'-UTR element, and increasing the levels of HuR decreased CELF1 binding to Myc mRNA. In contrast, increasing the concentrations of CELF1 inhibited formation of the [HuR/Myc mRNA] complex. Depletion of cellular polyamines also increased CELF1 and enhanced CELF1 association with Myc mRNA, thus suppressing MYC translation. Moreover, ectopic CELF1 overexpression caused G1-phase growth arrest, whereas CELF1 silencing promoted cell proliferation. These results indicate that CELF1 represses MYC translation by decreasing Myc mRNA association with HuR and provide new insight into the molecular functions of RBPs in the regulation of intestinal mucosal growth.

Src-mediated caveolin-1 phosphorylation regulates intestinal epithelial restitution by altering Ca(2+) influx after wounding

Early mucosal restitution occurs as a consequence of intestinal epithelial cell (IEC) migration to reseal superficial wounds, but its exact mechanism remains largely unknown. Caveolin-1 (Cav1), a major component associated with caveolar lipid rafts in the plasma membrane, is implicated in many aspects of cellular functions. This study determined if c-Src kinase (Src)-induced Cav1 phosphorylation promotes intestinal epithelial restitution after wounding by activating Cav1-mediated Ca(2+) signaling. Src directly interacted with Cav1, formed Cav1-Src complexes, and phosphorylated Cav1 in IECs. Inhibition of Src activity by its chemical inhibitor PP2 or suppression of the functional caveolin scaffolding domain by caveolin-scaffolding domain peptides prevented Cav1-Src interaction, reduced Cav1 phosphorylation, decreased Ca(2+) influx, and inhibited cell migration after wounding. Disruption of caveolar lipid raft microdomains by methyl-β-cyclodextrin reduced Cav1-mediated Ca(2+) influx and repressed epithelial restitution. Moreover, Src silencing prevented subcellular redistribution of phosphorylated Cav1 in migrating IECs. These results indicate that Src-induced Cav1 phosphorylation stimulates epithelial restitution by increasing Cav1-mediated Ca(2+) signaling after wounding, thus contributing to the maintenance of gut mucosal integrity under various pathological conditions.

Abstract B227: Overexpression of microRNA 214-3p in esophageal cancer cells enhances sensitivity to chemotherapy-induced apoptosis by targeting CUG-binding protein 1 (CUGBP1) and survivin

Introduction: Survivin, a key regulator of apoptosis and cell division is overexpressed in esophageal cancer cells and has been correlated with decreased survival. Our previous studies indicate that the RNA-binding protein CUGBP1 is also overexpressed in esophageal cancer cells and contributes to survivin overexpression by stabilizing its mRNA. To date, little information exists on the regulation of CUGBP1 in esophageal cancer cells. Based on sequence analysis, miR 214-3p is predicted to bind both CUGBP1 and survivin mRNA with high binding affinity. The purposes of this study are to determine expression levels of miR 214-3p in esophageal cancer cells and to establish whether miR 214-3p directly interacts with CUGBP1 and survivin mRNA to regulate their expression and modulate sensitivity to chemotherapy-induced apoptosis.

Methods: Studies were conducted in human esophageal epithelial (hESO) cells and in TE7 and TE10 human esophageal cancer cells. Global microRNA expression in these cell lines was determined by microarray analysis and confirmed by real-time PCR. MiR 214-3p function was tested by its overexpression and silencing. Levels of protein expression were measured by Western blot. Levels of mRNA were measured by real-time PCR. Binding of miR 214-3p to CUGBP1 and survivin mRNA was examined by biotinylated RNA pull-down assays. mRNA stability was determined by measuring its half-life after addition of Actinomycin D. The apoptotic phenotype was examined by caspase expression using Western blot and flow cytometry.

Results: Levels of miR 214-3p in TE7 and TE10 esophageal cancer cells are reduced by approximately 3,000 log-fold in comparison to hESO cells. Biotinylated RNA-pull down assays confirm direct binding of miR 214-3p to CUGBP1 and survivin mRNA. CUGBP1 and survivin mRNA and protein levels are reduced in a time-dependent manner following miR 214-3p overexpression in TE7 and TE10 cells. Conversely, silencing miR 214-3p in hESO cells results in increased CUGBP1 and survivin mRNA and protein levels. The stability of both CUGBP1 and survivin mRNA is decreased following overexpression of miR 214-3p in TE7 cells. Caspase-3 protein levels are increased when TE7 cells are exposed to camptothecin following microRNA 214-3p overexpression.

Conclusion: MiR 214-3p expression is markedly reduced in TE7 and TE10 esophageal cancer cells relative to hESO cells. MiR 214-3p binds and destabilizes both CUGBP1 and survivin mRNA. Overexpression of miR 214-3p in esophageal cancer cells results in decreased expression of CUGBP1 and survivin and leads to increased sensitivity to chemotherapy-induced apoptosis. These results strongly support the supposition that the loss of miR 214-3p in esophageal cancer cells contributes to enhanced resistance to chemotherapy-induced apoptosis by leading to increased CUGBP1 and survivin expression.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B227.

Citation Format: Pornima Phatak, Daniel Mansour, Kimberly Byrnes, Shan Cao, Lan Liu, Ruiyun Li, Rao Jaladanki, Douglas J. Tuner, Jian Ying Wang, James M. Donahue. Overexpression of microRNA 214-3p in esophageal cancer cells enhances sensitivity to chemotherapy-induced apoptosis by targeting CUG-binding protein 1 (CUGBP1) and survivin. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B227.

Predictors of anastomotic leak after esophagectomy: an analysis of the society of thoracic surgeons general thoracic database

BACKGROUND

Anastomotic leak is an important cause of morbidity and mortality after esophagectomy. Few studies have targeted risk factors for the development of leak after esophagectomy. The purpose of this study is to use The Society of Thoracic Surgeons Database to identify variables associated with leak after esophagectomy.

METHODS

The Society of Thoracic Surgeons Database was queried for patients treated with esophagectomy for esophageal cancer between 2001 and 2011. Univariate and multivariate analysis of variables associated with an increased risk anastomotic leak was performed.

RESULTS

There were 7,595 esophagectomies, with 804 (10.6%) leaks. Thirty-day mortality and length of stay were higher for patients with anastomotic leak. Mortality in patients requiring surgical management was 11.6% (38 of 327) compared with 4.4% (20 of 458) in medically managed leaks (p < 0.001). The leak rate was higher in patients with cervical anastomosis compared with those with intrathoracic anastomoses, 12.3% versus 9.3%, respectively (p = 0.006). There was no difference in leak-associated mortality between the two approaches. Factors associated with leak on univariate analysis include obesity, heart failure, coronary disease, vascular disease, hypertension, steroids, diabetes, renal insufficiency, tobacco use, procedure duration greater than 5 hours, and type of procedure (p < 0.05). Multivariable regression analysis associated heart failure, hypertension, renal insufficiency, and type of procedure as risk factors for the development of leak (p < 0.05).

CONCLUSIONS

Anastomotic leak after esophagectomy is an important cause of postoperative mortality and increased length of stay. We have identified important risk factors for the development of esophageal anastomotic leak after esophagectomy. Further studies aimed at risk reduction are warranted.

Sphingosine kinase 1 overexpression stimulates intestinal epithelial cell proliferation through increased c-Myc translation

Sphingosine-1-phosphate (S1P), through mechanisms that are not completely understood, is shown to modulate cellular proliferation, which is critically important for maintaining the integrity of intestinal epithelium. Here, we show that increased S1P promotes proliferation in intestinal epithelial cells. We found that overexpression of sphingosine kinase 1 (SphK1), the rate-limiting enzyme for S1P synthesis, significantly increased cell proliferation and that this occurred through enhanced expression of c-Myc. Further, we found that the increased pattern of expression of c-Myc occurred predominantly due to its increased translation. The overexpressed SphK1 led to increased checkpoint kinase 2 and enhanced HuR phosphorylation which allowed for increased translation of c-Myc mRNA through HuR binding at the 3'-untranslated regions. Our findings demonstrate that S1P modulates intestinal cell proliferation and provides new insights as to the mechanistic actions of SphK1 and S1P in maintaining intestinal epithelial homeostasis.

Antibiotic susceptibility patterns of Crossiella equi and Amycolatopsis species causing nocardioform placentitis in horses

Nocardioform actinomycetes are significant causes of placentitis and abortions in horses. In the current study, antimicrobial susceptibility patterns of 38 Amycolatopsis spp. and 22 Crossiella equi isolates, the most common nocardioform actinomycetes causing placentitis in horses, were evaluated. Antimicrobial susceptibilities of these isolates were tested by broth microdilution method in a commercial system, which was designed for Nocardia spp., fast-growing Mycobacterium spp., and other aerobic actinomycetes. The minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC90) of the following antibiotics tested for Amycolatopsis spp. were: 4 µg/ml for linezolid, trimethophrim–sulfametaxazole (TMP-SMX), and ciprofloxacin; 8 µg/ml for ceftriaxone, doxycycline, and minocycline; 16 µg/ml for amoxicillin–clavulanic acid, clarithromycin, and imipenem; >16 µg/ml for tobramycin; 32 µg/ml for amikacin and cefepime; and 128 µg/ml for cefoxitin. The MIC90 levels for C. equi were 0.25 µg/ml for doxycycline; ≤1 µg/ml for minocycline; 2 µg/ml for linezolid and TMP-SMX; 4 µg/ml for ciprofloxacin; 8 µg/ml for amoxicillin–clavulanic acid, ceftriaxone, and imipenem; 16 µg/ml for clarithromycin; >16 µg/ml for tobramycin; 32 µg/ml for cefepime; >64 µg/ml for amikacin; and 128 µg/ml for cefoxitin.

Polyamines inhibit the assembly of stress granules in normal intestinal epithelial cells regulating apoptosis

Polyamines regulate multiple signaling pathways and are implicated in many aspects of cellular functions, but the exact molecular processes governed by polyamines remain largely unknown. In response to environmental stress, repression of translation is associated with the assembly of stress granules (SGs) that contain a fraction of arrested mRNAs and are thought to function as mRNA storage. Here we show that polyamines modulate the assembly of SGs in normal intestinal epithelial cells (IECs) and that induced SGs following polyamine depletion are implicated in the protection of IECs against apoptosis. Increasing the levels of cellular polyamines by ectopic overexpression of the ornithine decarboxylase gene decreased cytoplasmic levels of SG-signature constituent proteins eukaryotic initiation factor 3b and T-cell intracellular antigen-1 (TIA-1)-related protein and repressed the assembly of SGs induced by exposure to arsenite-induced oxidative stress. In contrast, depletion of cellular polyamines by inhibiting ornithine decarboxylase with α-difluoromethylornithine increased cytoplasmic eukaryotic initiation factor 3b and TIA-1 related protein abundance and enhanced arsenite-induced SG assembly. Polyamine-deficient cells also exhibited an increase in resistance to tumor necrosis factor-α/cycloheximide-induced apoptosis, which was prevented by inhibiting SG formation with silencing SG resident proteins Sort1 and TIA-1. These results indicate that the elevation of cellular polyamines represses the assembly of SGs in normal IECs and that increased SGs in polyamine-deficient cells are crucial for increased resistance to apoptosis.

The prognostic importance of pathologically involved celiac node metastases in node-positive patients with carcinoma of the distal esophagus or gastroesophageal junction: a surgical series from the Mayo Clinic

The management of esophageal cancer with involvement of celiac lymph nodes is controversial. The purpose of this retrospective study was to evaluate the clinical importance of metastases to celiac lymph nodes in patients with carcinoma of the distal esophagus or gastroesophageal junction (GEJ) who undergo surgical treatment with curative intent. We reviewed the medical records of 310 patients who underwent definitive esophagectomy at the Mayo Clinic, Rochester, Minnesota, between 1976 and 1999 for carcinoma of the distal esophagus or GEJ. The disease location was distal esophagus in 163 and GEJ in 147. Fifty-two patients (17%) were found to have celiac node involvement. The survival of these patients was compared with that of 97 N0 patients and 161 N1 patients without celiac node involvement. Squamous cell carcinoma and adenocarcinomas were found in 24% and 76%, respectively. Ivor Lewis esophagectomy was the most common surgical procedure (76%), followed by transhiatal resection (14%) and modified Ivor Lewis procedure (5%). The median number of nodes resected was 15 (range, 2-45). The median survival of the entire group was 18.8 months. The median survival was 48 months (range, 1.6 months-22 years) for N0 patients and 15.9 months (range, 0.03 months-14.4 years) for N1 patients without celiac node disease (P < 0.001). The median survival was 11.7 months (range, 2.2 months-15.7 years) for celiac node-positive patients, and this difference was statistically significant when compared with survival in N0 patients (P= 0.001) but not when compared with that in N1 patients without celiac node disease (P= 0.57). Survival at 3 and 5 years was 61% and 45% for N0 patients, 21% and 9% for N1 patients without celiac node disease, and 18% and 11% for patients with celiac node disease, respectively. At 10 years, 7% of patients with celiac node involvement in their resected specimen were alive. By multivariate analysis, patients with 4 or more positive lymph nodes had the worst prognosis (risk ratio [RR], 2.63; 95% confidence interval [CI], 1.98-3.48), regardless of their location. We concluded that celiac node metastases were not an adverse prognostic indicator in patients with celiac node involvement compared with N1 patients without celiac node disease. Overall, the number of positive nodes, not their location, correlated best with survival. Although median survival was poor, a small number of patients with resected celiac node disease had long-term survival. Patients with undetected celiac node disease at the time of surgical resection who were subsequently found to have celiac node involvement appeared to have a prognosis similar to that of patients with stage III disease. Therefore, treatment with curative intent should be considered for fit patients with celiac node disease.

Induced ATF-2 represses CDK4 transcription through dimerization with JunD inhibiting intestinal epithelial cell growth after polyamine depletion

Intestinal epithelium is a rapidly self-renewing tissue in the body, and its homeostasis is tightly regulated by numerous factors including polyamines. Decreased levels of cellular polyamines increase activating transcription factor (ATF)-2, but the exact role and mechanism of induced ATF-2 in the regulation of intestinal epithelial cell (IEC) growth remain elusive. Cyclin-dependent kinase (CDK) 4 is necessary for the G1-to-S phase transition during the cell cycle, and its expression is predominantly controlled at the transcription level. Here, we reported that induced ATF-2 following polyamine depletion repressed CDK4 gene transcription in IECs by increasing formation of the ATF-2/JunD heterodimers. ATF-2 formed complexes with JunD as measured by immunoprecipitation using the ATF-2 and JunD antibodies and by glutathione S-transferase (GST) pull-down assays using GST-ATF-2 fusion proteins. Studies using various mutants of GST-ATF-2 revealed that formation of the ATF-2/JunD dimers depended on the COOH-terminal basic region-leucine zipper domain of ATF-2. Polyamine depletion increased ATF-2/JunD complex and inhibited CDK4 transcription as indicated by a decrease in the levels of CDK4-promoter activity and its mRNA. ATF-2 silencing not only prevented inhibition of CDK4 transcription in polyamine-deficient cells but also abolished repression of CDK4 expression induced by ectopic JunD overexpression. ATF-2 silencing also promoted IEC growth in polyamine-depleted cells. These results indicate that induced ATF-2/JunD association following polyamine depletion represses CDK4 transcription, thus contributing to the inhibition of IEC growth.

Invited review: the role of caterpillars in mare reproductive loss syndrome: a model for environmental causes of abortion

A new abortigenic disease, now known as mare reproductive loss syndrome (MRLS), significantly affected the horse industry in the Ohio River Valley of the United States in late April and early May of 2001 and 2002. In 2001, approximately 25% of all pregnant mares aborted within several weeks (over 3,000 mares lost pregnancies), and abortion rates exceeded 60% on some farms. Mare reproductive loss syndrome struck hard and without warning, it was caused by something in the environment, it was not transmitted between animals, and it was not associated with any known abortigenic agent or disease. These experiments demonstrated that horses will inadvertently consume Eastern tent caterpillars (ETC) when the insects are present in the pasture or other feedstuffs, and MRLS-type abortions were induced in experimental animals (mares and pigs) by mixing ETC with the feed of the animals. Eastern tent caterpillars are hirsute (hairy) caterpillars, and the only part of the caterpillar that caused MRLS abortions was the cuticle. The experiments revealed that the setae (hairs) embed into the submucosa of the alimentary tract creating microgranulomatous lesions. It is hypothesized that the alimentary tract lesions allow bacteria from the alimentary tract of the mare, principally streptococci, actinobacilli, and to a lesser extent enterococci, to invade the circulatory system of the mare. The bacteria then establish infections in tissues where the immune surveillance of the mare is reduced, such as the fetus and placenta. Fetal and placental fluid bacterial infections lead to fetal death and abortion characteristic of MRLS. Inadvertent ingestion of ETC by pregnant mares causes MRLS. Currently the only known means to prevent MRLS is to avoid exposure of horses, particularly pregnant mares, to ETC and probably most hirsute caterpillars.

Streptomyces atriruber sp. nov. and Streptomyces silaceus sp. nov., two novel species of equine origin

Two actinomycete strains, NRRL B-24165(T) and NRRL B-24166(T), isolated from lesions on equine placentas in Kentucky, USA, were analysed using a polyphasic taxonomic approach. On the basis of phylogenetic analysis of 16S rRNA gene sequences, morphological observations and the presence of ll-diaminopimelic acid as the diagnostic diamino acid in whole-cell hydrolysates, the new isolates clearly belonged to the genus Streptomyces. Analyses of the phylogenetic positions of strains NRRL B-24165(T) and NRRL B-24166(T) based on 16S rRNA gene sequences of all recognized species of the genus Streptomyces, as well as evaluation of morphological and physiological characteristics, demonstrated that the new isolates could be differentiated from all recognized species and therefore represented novel species. It is proposed that the new strains represent two novel species for which the names Streptomyces atriruber sp. nov. (type strain NRRL B-24165(T)=DSM 41860(T)=LDDC 6330-99(T)) and Streptomyces silaceus sp. nov. (NRRL B-24166(T)=DSM 41861(T)=LDDC 6638-99(T)) are proposed. The species names are based on the distinctive colours of the substrate mycelium of these strains, dark red and deep orange-yellow, respectively.

Lentzea kentuckyensis sp. nov., of equine origin

A novel actinomycete, designated strain LDDC 2876-05T, was isolated from an equine placenta during the course of routine diagnostic tests for nocardioform placentitis. In a preliminary study, the strain was observed to be phylogenetically distinct from the generaCrossiellaandAmycolatopsisand probably a member of the genusLentzea.A polyphasic study of strain LDDC 2876-05Tconfirmed its identification as a member ofLentzeaon the basis of its chemotaxonomic and morphological similarity to all of the known species of the genus. Moreover, the strain could be distinguished from other species with validly published names on the basis of its phylogenetic and physiological characteristics and its fatty acid profile. Therefore strain LDDC 2876-05Trepresents a novel species of the genusLentzea, for which the nameLentzea kentuckyensissp. nov. is proposed. The type strain is LDDC 2876-05T(=NRRL B-24416T=DSM 44909T).

Classification of Actinobacillus spp isolates from horses involved in mare reproductive loss syndrome

OBJECTIVE

To identify Actinobacillus spp isolates recovered from fetuses and pericardial fluid from horses affected with mare reproductive loss syndrome (MRLS) and determine whether these bacterial species are the same as those isolated from clinically normal horses.

SAMPLE POPULATION

Isolates of actinobacilli recovered from 18 horses with pericarditis and 109 fetuses aborted by mares affected by MRLS. Procedures-Actinobacillus spp isolates were identified to the level of species or subspecies by use of conventional phenotypic tests and biochemical and enzyme test kits. The 16S rRNA gene from selected isolates was amplified, purified, and sequenced. Sequence data were compared with sequence data for actinobacilli in GenBank.

RESULTS

Of the 109 isolates obtained from fetuses, 14 were Actinobacillus equuli subsp equuli, 65 were A equuli subsp haemolyticus, 28 were Bisgaard taxon 10-like bacterium, and 2 were Actinobacillus genomospecies 1. Of the 18 isolates from horses with pericarditis, 4 were A equuli subsp equuli, 13 were A equuli subsp haemolyticus, and 1 was Bisgaard taxon 10-like bacterium. Comparisons with published data and GenBank data revealed that the isolates recovered from horses with MRLS were the same as those isolated from the oral cavity or alimentary tract of healthy horses.

CONCLUSIONS AND CLINICAL RELEVANCE

Actinobacillus spp isolates recovered from fetuses and pericardial fluid samples of horses affected by MRLS in 2001 to 2003 were identical to Actinobacillus spp found in the oral cavity and alimentary tracts of healthy horses.

Nocardioform placentitis with isolation ofAmycolatopsisspp in a Florida-bred mare

CASE DESCRIPTION

A 4-year-old Thoroughbred mare was evaluated because of placental abnormalities and a retained placental remnant.

CLINICAL FINDINGS

Microbial culture of the placenta yielded pure growth of Amycolatopsis spp. Histologic examination of the placenta revealed a focally expanding chorionitis with intralesional gram-positive filamentous bacilli and multifocal allantoic adenomatous hyperplasia on the apposing allantoic surface.

TREATMENT AND OUTCOME

Treatment with lavage and oxytocin resulted in expulsion of the placental remnant within hours of parturition. The mare did not become pregnant again despite multiple breedings. The foal appeared healthy but died of complications during an elective surgical procedure at 7 weeks of age.

CONCLUSIONS AND CLINICAL RELEVANCE

To the author's knowledge, all previously confirmed cases of nocardioform placentitis have been in mares bred in the central Kentucky region. Indications that the pathogen in the mare reported here is a different species than that isolated in Kentucky suggest that this is an emerging disease. Mares with nocardioform placentitis usually do not have the same clinical signs as mares with placentitis resulting from an ascending pathogen.

Meningoencephalomyelitis in a foal due to Salmonella agona infection

CASE HISTORY

A neonatal Thoroughbred foal was presented with rib fractures and left forelimb lameness secondary to dystocia.

CLINICAL FINDINGS

The foal developed a head tilt, seizures and watery diarrhoea during hospitalisation and died at 7 days of age. Histological examination of the brain and spinal cord revealed a suppurative meningoencephalomyelitis with vasculitis, and numerous intralesional, gram-negative bacilli. Similar microscopic lesions were noted in the lungs, renal medullary interstitium, and umbilicus. Bacilli in the brain, spinal cord and umbilicus were identified immunohistochemically as Salmonella group B. Salmonella agona was isolated in pure culture from the brain, lung, liver, kidney, and intestine.

CONCLUSION

This is the first report of meningoencephalomyelitis and septicaemia due to Salmonella infection in an equine neonate.

Mouse models of subcutaneous spleen reservoir for multiple portal venous injections to treat liver malignancies

Dog and rat animal models have been developed for repeated intravascular administrations to the liver. However, mice have generally been considered too small to use for these models. This study describes the development of mouse models that permit the establishment of liver metastases that can be subsequently treated by repeated injections into the portal venous system. A mini-laparotomy is done to mobilize the spleen and transpose it to a s.c. pocket with its vascular pedicle intact. A suspension of single tumor cells is then inoculated into the portal vein to establish diffuse liver metastases. These tumors may be treated by simple percutaneous injections directly into the s.c. whole spleen reservoir. The ease of injection into the s.c. spleen permits repeated injections into the portal venous system. The usefulness of this model was shown in experiments revealing that multiple portal venous administrations of a replication-conditional, oncolytic herpes simplex virus mutant are more effective than a single portal venous administration. In a modification of this model, the spleen is first split into two, leaving intact the vascular pedicle for each half of the spleen. Tumor cells are inoculated into one hemi-spleen, which is then resected 10 minutes later. The other hemi-spleen is transposed to the s.c. position, thereby permitting subsequent repetitive portal venous injections via percutaneous injections into the s.c. hemi-spleen. These mouse models are useful for a wide range of studies.

Equine abortion and premature birth associated with Cellulosimicrobium cellulans infection

During the 2002 and 2003 foaling seasons, Cellulosimicrobium (Cellumonas) cellulans (formerly Oerskovia xanthineolytica) was the principal microorganism isolated from fetal tissues or placentas from cases of equine abortion, premature birth, and term pregnancies. Significant pathologic findings included chronic placentitis and pyogranulomatous pneumonia. In addition, microscopic and macroscopic alterations in the allantochorion from 4 of 7 cases of placentitis were similar to those caused by Crossiella equi and other nocardioform bacteria. This report confirms a causative role of C. cellulans infection in equine abortion.

Selectivity of an oncolytic herpes simplex virus for cells expressing the DF3/MUC1 antigen

Replication-conditional viruses destroy tumors in a process referred to as viral oncolysis. An important prerequisite for this cancer therapy strategy is use of viruses that replicate preferentially in neoplastic cells. In this study the DF3/MUC1 promoter/enhancer sequence is used to regulate expression of gamma(1)34.5 to drive replication of a Herpes simplex virus 1 (HSV-1) mutant (DF3gamma34.5) preferentially in DF3/MUC1-positive cells. HSV-1 gamma(1)34.5 functions to dephosphorylate elongation initiation factor 2alpha, which is an important step for robust HSV-1 replication. After DF3gamma34.5 infection of cells, elongation initiation factor 2alpha phosphatase activity and viral replication were observed preferentially in DF3/MUC1-positive cells but not in DF3/MUC1-negative cells. Regulation of gamma(1)34.5 function results in preferential replication in cancer cells that express DF3/MUC1, restricted biodistribution in vivo, and less toxicity as assessed by LD(50). Preferential replication of DF3gamma34.5 was observed in DF3/MUC1-positive liver tumors after intravascular perfusion of human liver specimens. DF3gamma34.5 was effective against carcinoma xenografts in nude mice. Regulation of gamma(1)34.5 by the DF3/MUC1 promoter is a promising strategy for development of HSV-1 mutants for viral oncolysis.

Eastern tent caterpillars (Malacosoma americanum) cause mare reproductive loss syndrome

A new equine abortigenic disease, mare reproductive loss syndrome (MRLS), was recognized and significantly impacted the Ohio Valley in the springs of 2001 and 2002. MRLS caused approximately 330 million US dollars in losses in 2001. An epidemiological investigation of MRLS associated occurrence of the disease with exposure to eastern tent caterpillars (M. americanum). This work investigates the epidemiological association between M. americanum and MRLS to determine if this association was correlative or causative. A pilot study and simulated exposure to M. americanum and their excreta on pasture grasses. The pilot study advanced exposure of pregnant mares to M. americanum materials and 18 of the 29 mares in the study aborted with symptoms of MRLS before other cases were reported in the region. In, three of seven mares exposed to M. americanum aborted, while mares in control (n=6) and M. americanum frass (n=7) treatments had no losses. In, mares were fed frozen insect larvae in feed buckets mixed with oats. Abortions occurred in three of five mares receiving frozen M. americanum, while mares that were fed autoclaved M. americanum (n=5) or frozen gypsy moth larvae (n=4) had no abortions due to MRLS. In, M. americanum larvae were dissected and fractionated. Statistically significant numbers of abortions occurred only in the positive control group and in association with the M. americanum exoskeleton. All abortions induced by exposure to M. americanum exhibited changes in echogenicity of fetal fluids and bacteriological findings post abortion that were consistent with MRLS. These studies support the hypothesis that ingestion of M. americanum larvae induces the MRLS-type equine abortions, and provide experimental evidence that this lepidopteran larva can cause an abortigenic disease in a vertebrate host.

Oncolysis by viral replication and inhibition of angiogenesis by a replication-conditional herpes simplex virus that expresses mouse endostatin

BACKGROUND

In preclinical models, infection of tumors by oncolytic strains of herpes simplex virus 1 (HSV-1) resulted in the destruction of tumor cells by viral replication and release of progeny virion that infected and destroyed adjacent tumor cells. However, complete tumor regression was rarely observed.

METHODS

To augment the antitumor effect of viral oncolysis, a replication conditional HSV-1 mutant (HSV-Endo) was constructed in which the murine endostatin gene was incorporated into the HSV-1 genome.

RESULTS

Replication of HSV-Endo effectively destroyed several colon carcinoma cell lines in vitro. Secretion of endostatin by HSV-Endo-infected HT29 human colon carcinoma cells was confirmed by Western blot analysis. The secreted endostatin was biologically active as assessed in a chick chorioallantoic membrane assay. Importantly, endostatin production at the site of viral replication did not inhibit viral replication. Direct injection of HSV-Endo into flank tumors caused tumor destruction, and some of the HSV-Endo-treated flank tumors completely sloughed. Immunohistochemical staining of the tumors revealed a decreased number of blood vessels in the HSV-Endo-treated group versus the control group.

CONCLUSIONS

The oncolytic HSV-1 mutant HSV-Endo provided a two-pronged therapy; namely, inhibition of angiogenesis and direct tumor cell destruction by viral replication.

Amycolatopsis kentuckyensis sp. nov., Amycolatopsis lexingtonensis sp. nov. and Amycolatopsis pretoriensis sp. nov., isolated from equine placentas

Actinomycete strains isolated from lesions on equine placentas from two horses in Kentucky and one in South Africa were subjected to a polyphasic taxonomic study. Chemotaxonomic and morphological characteristics indicated that the isolates are members of the genus AMYCOLATOPSIS: On the basis of phylogenetic analysis of 16S rDNA sequences, the isolates are related most closely to Amycolatopsis mediterranei. Physiological characteristics of these strains indicated that they do not belong to A. mediterranei and DNA relatedness determinations confirmed that these strains represent three novel species of the genus Amycolatopsis, for which the names Amycolatopsis kentuckyensis (type strain, NRRL B-24129(T)=LDDC 9447-99(T)=DSM 44652(T)), Amycolatopsis lexingtonensis (type strain, NRRL B-24131(T)=LDDC 12275-99(T)=DSM 44653(T)) and Amycolatopsis pretoriensis (type strain, NRRL B-24133(T)=ARC OV1 0181(T)=DSM 44654(T)) are proposed.