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Defining a Conserved Role for Palladin in Tumor Progression
S130
Surgical Forum Abstracts
analysis revealed that sorafenib inhibited p70S6K phosphorylation, and this effect correlated with inhibition of p-4E-BP1, p-eIF4E, and total eIF4E. Sorafenib also suppressed p-GSK-3-beta, active beta-catenin, and cyclinD1. CONCLUSIONS: Our results demonstrate that sorafenib suppresses the mTOR signaling cascade in desmoid-derived cells, suggesting that sorafenib may have antitumor activity in DTs due to inhibition of translation. Sorafenib also demonstrated inhibition of downstream targets of Wnt signaling, such as cyclinD1. Additional studies to examine the efficacy of combination therapy with sorafenib and an mTOR inhibitor are warranted. Defining a Conserved Role for Palladin in Tumor Progression Austin Cannon, Meredith K Owen, PhD, Emily H Chang, MD, Brian C Klazynski, MD, Jonathan Hollyfield, MD, Michael Kerber, PhD, Carol Otey, PhD, Hong Jin Kim, MD, FACS University of North Carolina School of Medicine, Chapel Hill, NC INTRODUCTION: The stroma surrounding pancreatic cancers plays an important role in metastasis. Tumor associated fibroblasts (TAFs) comprise much of the tumor microenvironment and promote cancer cell migration and growth. In pancreas tumors, palladin, an actin-associated protein existing as nine distinct isoforms, is overexpressed in TAFs and contributes to their invasive phenotype. Our aim was to examine the expression, distribution, and functional role of palladin in other solid tumors, and characterize its role in tumor invasiveness. METHODS: Human tumor and matched normal tissues were obtained for the following cancers: pancreas, colon, stomach, lung, and melanoma. Immunohistochemistry was performed with isoform-specific antibodies to assess palladin’s presence and localization. RNA analysis (RNASeq) was also performed, comparing wild-type pancreatic TAFs vs palladin knockdown TAFs to ask if palladin regulates gene expression. RESULTS: Immunohistochemistry demonstrated that palladin isoform 4 was strongly detected within the tumor stroma of all cancers examined. Isoform 6 localized to the nuclear compartment in multiple cell types in both normal and tumor samples. RNASeq revealed multiple pathways that were differentially expressed, including TGF-B and matrix metalloproteinases, in palladin knockdown TAFs. CONCLUSIONS: Palladin is strongly expressed in the stroma of multiple cancers, and is present within the nucleus of various cell types. These findings, along with the RNASeq data, implicate palladin as a key regulatory protein, and suggest it may play a critical role in the creation of desmoplastic tumor stroma. This represents a novel mechanism whereby palladin promotes tumor invasion and suggests a broader role for palladin than previously recognized.
J Am Coll Surg
MicroRNAs in Pancreatic Fibroblast Induced by Tumor Cells Andrew H Nguyen, MD, Luyi Li, MS, Paul A Toste, MD, Nanping Wu, Timothy R Donahue, MD, FACS David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment consists of a network of supporting cells, including tumor-associated fibroblasts (TAFs), which promote tumor cell (TC) invasion and metastasis, and contribute to PDAC’s extremely poor prognosis. MicroRNAs (miRs) have emerged as critical players in post-transcriptional regulation of pathways in cancer. In this study, we identified miRs in fibroblasts induced by pancreatic TCs. Further, we studied the effects suppressing one of these miRs in TAFs. METHODS: Primary pancreatic fibroblasts were cultured with MIA PaCa-2 TC conditioned media and RNA was analyzed by the NanoString MicroRNA Expression Assay. Stable miR knockdown (KD) was achieved by lentiviral vector. Migration was determined by scratch assay and invasion by modified Boyden chamber. TC proliferation was measured by MTT assay. In vivo tumor growth was evaluated by subcutaneous TC and TAF co-implantation in NSG mice. RESULTS: 62 induced miRs were identified to have >50% increase or 30% decrease in expression in primary pancreatic fibroblasts. The most prevalent induced miR with 2-fold increase in expression was miR-21. Stable miR-21 KD in TAFs achieved a 75% decrease in expression. miR-21 KD TAFs had decreased ability to migrate and were less invasive. miR-21 KD TAF conditioned media induced less rapid TC proliferation. Further, TCs coimplanted with miR-21 KD TAFs showed decreased tumor size, compared to TCs co-implanted with controls. CONCLUSIONS: Pancreatic cancer TCs can induce tumor supportive miRs in TAFs. miR-21 KD in PDAC TAFs results in decreased TAF migration and invasion, as well as reduced ability to support in vitro and in vivo tumor growth. The Liver Regeneration Response after Open and Laparoscopic Left Partial Hepatectomy in an Experimental Porcine Model, Integrated Constantinos Mammas, MD, MSc, PhD, Nikolaos Arkadopoulos, MD, PhD, FACS, Nikolaos Kavantzas, MD, PhD, Ismene A Dontas, DVM, PhD, Georgia Kostopanatiotou, MD, PhD, Thomas Kotsis, MD, PhD, Vasileios Smyrniotis, MD, PhD Surgical Laboratory of Prof. C. Tountas, Athens, Greece INTRODUCTION: The liver regeneration in the remnant liver of a porcine experimental model after Open (OLPH) and Laparoscopic Left Partial Hepatectomy (LLPH) is compared. METHODS: Two pairs of double-series of twenty-nine liver tissues taken from twenty nine porcine livers, after OLPH or LLPH (PD0)
Surgical Forum Abstracts
analysis revealed that sorafenib inhibited p70S6K phosphorylation, and this effect correlated with inhibition of p-4E-BP1, p-eIF4E, and total eIF4E. Sorafenib also suppressed p-GSK-3-beta, active beta-catenin, and cyclinD1. CONCLUSIONS: Our results demonstrate that sorafenib suppresses the mTOR signaling cascade in desmoid-derived cells, suggesting that sorafenib may have antitumor activity in DTs due to inhibition of translation. Sorafenib also demonstrated inhibition of downstream targets of Wnt signaling, such as cyclinD1. Additional studies to examine the efficacy of combination therapy with sorafenib and an mTOR inhibitor are warranted. Defining a Conserved Role for Palladin in Tumor Progression Austin Cannon, Meredith K Owen, PhD, Emily H Chang, MD, Brian C Klazynski, MD, Jonathan Hollyfield, MD, Michael Kerber, PhD, Carol Otey, PhD, Hong Jin Kim, MD, FACS University of North Carolina School of Medicine, Chapel Hill, NC INTRODUCTION: The stroma surrounding pancreatic cancers plays an important role in metastasis. Tumor associated fibroblasts (TAFs) comprise much of the tumor microenvironment and promote cancer cell migration and growth. In pancreas tumors, palladin, an actin-associated protein existing as nine distinct isoforms, is overexpressed in TAFs and contributes to their invasive phenotype. Our aim was to examine the expression, distribution, and functional role of palladin in other solid tumors, and characterize its role in tumor invasiveness. METHODS: Human tumor and matched normal tissues were obtained for the following cancers: pancreas, colon, stomach, lung, and melanoma. Immunohistochemistry was performed with isoform-specific antibodies to assess palladin’s presence and localization. RNA analysis (RNASeq) was also performed, comparing wild-type pancreatic TAFs vs palladin knockdown TAFs to ask if palladin regulates gene expression. RESULTS: Immunohistochemistry demonstrated that palladin isoform 4 was strongly detected within the tumor stroma of all cancers examined. Isoform 6 localized to the nuclear compartment in multiple cell types in both normal and tumor samples. RNASeq revealed multiple pathways that were differentially expressed, including TGF-B and matrix metalloproteinases, in palladin knockdown TAFs. CONCLUSIONS: Palladin is strongly expressed in the stroma of multiple cancers, and is present within the nucleus of various cell types. These findings, along with the RNASeq data, implicate palladin as a key regulatory protein, and suggest it may play a critical role in the creation of desmoplastic tumor stroma. This represents a novel mechanism whereby palladin promotes tumor invasion and suggests a broader role for palladin than previously recognized.
J Am Coll Surg
MicroRNAs in Pancreatic Fibroblast Induced by Tumor Cells Andrew H Nguyen, MD, Luyi Li, MS, Paul A Toste, MD, Nanping Wu, Timothy R Donahue, MD, FACS David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment consists of a network of supporting cells, including tumor-associated fibroblasts (TAFs), which promote tumor cell (TC) invasion and metastasis, and contribute to PDAC’s extremely poor prognosis. MicroRNAs (miRs) have emerged as critical players in post-transcriptional regulation of pathways in cancer. In this study, we identified miRs in fibroblasts induced by pancreatic TCs. Further, we studied the effects suppressing one of these miRs in TAFs. METHODS: Primary pancreatic fibroblasts were cultured with MIA PaCa-2 TC conditioned media and RNA was analyzed by the NanoString MicroRNA Expression Assay. Stable miR knockdown (KD) was achieved by lentiviral vector. Migration was determined by scratch assay and invasion by modified Boyden chamber. TC proliferation was measured by MTT assay. In vivo tumor growth was evaluated by subcutaneous TC and TAF co-implantation in NSG mice. RESULTS: 62 induced miRs were identified to have >50% increase or 30% decrease in expression in primary pancreatic fibroblasts. The most prevalent induced miR with 2-fold increase in expression was miR-21. Stable miR-21 KD in TAFs achieved a 75% decrease in expression. miR-21 KD TAFs had decreased ability to migrate and were less invasive. miR-21 KD TAF conditioned media induced less rapid TC proliferation. Further, TCs coimplanted with miR-21 KD TAFs showed decreased tumor size, compared to TCs co-implanted with controls. CONCLUSIONS: Pancreatic cancer TCs can induce tumor supportive miRs in TAFs. miR-21 KD in PDAC TAFs results in decreased TAF migration and invasion, as well as reduced ability to support in vitro and in vivo tumor growth. The Liver Regeneration Response after Open and Laparoscopic Left Partial Hepatectomy in an Experimental Porcine Model, Integrated Constantinos Mammas, MD, MSc, PhD, Nikolaos Arkadopoulos, MD, PhD, FACS, Nikolaos Kavantzas, MD, PhD, Ismene A Dontas, DVM, PhD, Georgia Kostopanatiotou, MD, PhD, Thomas Kotsis, MD, PhD, Vasileios Smyrniotis, MD, PhD Surgical Laboratory of Prof. C. Tountas, Athens, Greece INTRODUCTION: The liver regeneration in the remnant liver of a porcine experimental model after Open (OLPH) and Laparoscopic Left Partial Hepatectomy (LLPH) is compared. METHODS: Two pairs of double-series of twenty-nine liver tissues taken from twenty nine porcine livers, after OLPH or LLPH (PD0)