BMP ligand-receptor interactions contribute to experimental tracheoesophageal fistula

CARDIOTHORACIC SURGERY II chemoresistance. We screened siRNA duplexes for activity against BCL-XL. Using an optimal sequence, we then developed a plasmid-based delivery system.

GENERAL THORACIC/TRANSPLANTATION BMP ligand-receptor interactions contribute to experimental tracheoesophageal fistula

METHODS: MM cell lines (I-45, REN) were treated with multiple therapeutic and control siRNA double-strand constructs. Survival was assessed by XTT, and real-time PCR and western blot were performed for BCL-XL. I-45 cells were transfected with therapeutic (p605) and control (pS) plasmid vectors. BCL-XL was evaluated by western blot, and a clonogenic assay was performed. Nude mice with subcutaneous I-45 tumor xenografts were treated with p605, pS, or D5W. Immunostaining for BCL-XL was performed on tumor samples and tumor growth measured.

Troy Spilde MD, Amanda Crowley BA, Sheilendra Mehta MD, Daniel Ostlie MD, Krishna Prasadan PhD, Mark Hembree BA, Barry Preuett BS, Sidhartha Tulachan MD, PhD, George W Holcomb III, MD, FACS, George Gittes MD, FACS, Charles Snyder MD, FACS University of Missouri Kansas City School of Medicine Kansas City, MO INTRODUCTION: The mechanism of formation of esophageal atresia with tracheoesophageal fistula (EA/TEF) remains unclear. Previously, we demonstrated that the fistula tract develops from a trifurcation of the embryonic lung bud. The fistula tract then grows caudally without branching, unlike the bronchi, which branch normally. Bone Morphogenetic Protein (BMP) signaling is critical to lung branching. We hypothesized that defects in BMP signaling may be causative in EA/TEF.

RESULTS: One duplex (xl605) was most effective in reducing cell survival (25.25% I-45 and 26.72% REN). A marked decrease in bcl-xl RNA (3.06 fold, p⬍.01) and protein was noted, and xl605 was then used as a template for plasmid construction. In I45, p605 demonstrated reduction of BCL-XL protein and colony growth (71.3 treated vs 179.3 control, p ⫽ .008). At eight weeks, mean tumor volume (mm3) in the treated animals was significantly decreased (112.62⫹/⫺18.9 treated vs. 272.9⫹/⫺ 30.8 control, p ⫽ ⬍.001), and corresponded with tumor weight.

METHODS: Adriamycin was administered to pregnant rats to induce TEF. Foregut microdissection was performed at E13 and E17. Tissues were analyzed using immunohistochemistry for BMP ligands (BMP2, BMP4, BMP7) and receptors (BMPRIA, BMPRIB, BMPRII).

CONCLUSIONS: Synthesized and vector delivered siRNA can silence MM BCL-XL expression in vitro and in vivo. As gene therapy delivery techniques improve, the potential for inhibiting the function of BCL-XL using siRNA may be clinically relevant in chemoresistant tumors such as mesothelioma.

RESULTS: All three BMP ligands were present at E13, specifically on the luminal side of the esophageal mucosa, but not in fistula or lung. By E17 the ligands were present in the mucosa of esophagus and fistula, but remained absent in lung. At E17 all BMP receptors also were localized to only the luminal surface of esophagus and fistula. In lung, only BMPRII was present.

Oncolytic herpes simplex viral therapy effectively treats and improves survival in a murine model of pleural malignant mesothelioma

CONCLUSIONS: Proper BMP signaling necessitates heterodimerization of type II receptor and type I receptors. Heterodimerization appears feasible in both fistula tract and esophagus at E17, but not in lung, where the type I receptor is absent. In addition, early intestinalization of the lung bud in the region of the fistula is possible because both type I and type II receptors are present on the luminal surface with BMP ligands locally.

Prasad S Adusumilli MBBS, Brendon M Stiles MD, Mei-Ki Chan BS, Valerie W Rusch MD, FACS, Yuman Fong MD, FACS Memorial Sloan-Kettering Cancer Center, New York New York, NY INTRODUCTION: Replication-competent, attenuated herpes simplex virus type-1 (HSV-1) selectively infect and lyse cancer cells. The purpose of this study was to determine whether HSV-1 therapy was cytotoxic to malignant mesothelioma (MM) cell lines and improves survival in a murine model of MM.

Post-transcriptional silencing of BCL-XL in mesothelioma using synthesized oligonucleotides and an H1 promoter driven vector encoding siRNA Jonathan C Daniel MD, Xiaobo Cao MD, Philip A Rascoe MD, Steven D Miller MD, W Roy Smythe MD, FACS MD Anderson Cancer Center Houston, TX

METHODS: In Vitro: Eleven human MM cell lines were infected with HSV-1 strain, NV1066 at multiplicities of infection (MOI: number of viral particles per cancer cell) of 0.01, 0.1 or 1. Cell kill was determined by LDH (Lactate dehydrogenase release) assay and viral replication by plaque assay. In Vivo: MSTO-211H, MM cells were injected percutaneously into the pleural cavity of the

INTRODUCTION: Gene silencing via RNA interference (RNAi) may have therapeutic potential. Anti-apoptotic BCL-XL overexpression in mesothelioma (MM) is related to pathogenesis and

© 2004 by the American College of Surgeons Published by Elsevier Inc.

ISSN 1072-7515/04/$30.00

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