Microbiota transfer following liver surgery involves microbial extracellular vesicle migration that affects liver immunity.

BACKGROUND: Short-term perioperative administration of probiotics was shown to alleviate postoperative complications and promote liver recovery among patients undergoing resection for liver malignancy. The mechanisms by which probiotic bacteria effectively influence the gut microbiome composition during the perioperative time are controversial. Here, we aim to elucidate the short-term direct biological effect of probiotic microbiota-derived vesicles on host liver cells during the perioperative period. METHODS: Probiotic-derived vesicles (pbMVs) were administered postoperatively. pbMVs were isolated and characterized from probiotics, mainly from the bacteria genus Lactobacillus, Bifidobacterium, and Lactococcus. Mice underwent bile duct ligation, sham laparotomy (SHAM), or 70% partial hepatectomy (70%PH). pbMVs were tracked in vivo, and intrahepatic cellular and molecular aspects were analyzed by flow cytometry and qRT-PCR techniques. Liver sinusoidal endothelial cells (LSECs) analysis for Vascular Cell Adhesion Molecule-1(VCAM-1) expression following pbMV stimulation of cultured liver non-parenchymal cells which had been activated by LPS. RESULTS: The administered pbMV rapidly translocated to the liver after surgery. pbMV administrations following surgeries enhanced neutrophil clearance; there was a dramatic decline in the liver neutrophil-to-lymphocyte ratio Ly6G+/CD3+ and an increase in IL6 levels. pbMVs reduced intrahepatic VCAM1 and ICAM2 expression compared with control following SHAM and decrease in IL10 levels following 70%PH. The administration of pbMV improved liver regeneration 72 hours following surgical liver resection with a significant decrease in IL17 expression. pbMVs modulated VCAM-1 on liver sinusoidal endothelial cells in liver cell culture. CONCLUSIONS: Our study findings provide mechanistic insights into the liver-gut axis following surgery and illustrate how probiotic vesicles can reduce adhesion molecule expression and affect immune cell invasion and liver immunity, resulting in improved liver recovery following hepatic surgery.

Gastric Cancer-Derived Extracellular Vesicles (EVs) Promote Angiogenesis via Angiopoietin-2.

Angiogenesis is an important control point of gastric cancer (GC) progression and metastasis. Angiopoietin-2 (ANG2) is a key driver of tumor angiogenesis and metastasis, and it has been identified in primary GC tissues. Extracellular vesicles (EVs) play an important role in mediating intercellular communication through the transfer of proteins between cells. However, the expression of ANG2 in GC-EVs has never been reported. Here, we characterized the EV-mediated crosstalk between GC and endothelial cells (ECs), with particular focus on the role of ANG2. We first demonstrate that ANG2 is expressed in GC primary and metastatic tissues. We then isolated EVs from two different GC cell lines and showed that these EVs enhance EC proliferation, migration, invasion, and tube formation in vitro and in vivo. Using an angiogenesis protein array, we showed that GC-EVs contain high levels of proangiogenic proteins, including ANG2. Lastly, using Lenti viral ANG2-shRNA, we demonstrated that the proangiogenic effects of the GC-EVs were mediated by ANG2 through the activation of the PI3K/Akt signal transduction pathway. Our data suggest a new mechanism via which GC cells induce angiogenesis. This knowledge may be utilized to develop new therapies in gastric cancer.

Micro-RNA Expression Patterns Predict Metastatic Spread in Solid Pseudopapillary Neoplasms of the Pancreas.

Solid pseudopapillary neoplasm (SPN) of pancreas is a rare pancreatic neoplasm with a low metastatic potential. Up to 10% of patients with localized disease at presentation will develop systemic metastases, usually in the peritoneum or the liver. Due to the rarity of SPNs and the overall excellent prognosis, reliable prognostic factors to predict malignant biological behavior remain undetermined. Therefore, we aimed to define clinical, histological, and microRNA patterns that are associated with metastatic disease. We conducted a retrospective single center study on all patients operated for SPN of pancreas between 1995 and 2018. Clinical and pathological data were collected, and expression patterns of 2,578 human microRNAs were analyzed using microRNA array (Affimetrix 4.1) in normal pancreases (NPs), localized tumors (LTs), and metastatic tumors (MTs). The diagnosis of SPN was confirmed in 35 patients who included 28 females and 3 males, with a mean age of 33.8 ± 13.9 years. The only clinical factor associated with metastases was tumor size (mean tumor size 5.20 ± 3.78 in LT vs. 8.13± 1.03 in MT, p < 0.012). Microscopic features of malignancy were not associated with metastases, nor were immunohistochemical stains, including the proliferative index KI67. Higher expressions of miR-184, miR-10a, and miR-887, and lower expressions of miR-375, miR-217, and miR-200c were observed in metastatic tissues on microarray, and validated by real-time polymerase chain reaction. Hierarchal clustering demonstrated that the microRNA expression pattern of MTs was significantly different from that of LTs. The only clinical factor associated with metastases of SPN of pancreas was tumor size. Histological features and immunohistological staining were not predictive of metastases. A panel of six microRNAs was differentially expressed in MTs, and these findings could potentially be used to predict tumor behavior. Validation of these results is needed in larger series.

5-Hydroxymethylcytosine as a clinical biomarker: Fluorescence-based assay for high-throughput epigenetic quantification in human tissues.

Epigenetic transformations may provide early indicators for cancer and other disease. Specifically, the amount of genomic 5-hydroxymethylcytosine (5-hmC) was shown to be globally reduced in a wide range of cancers. The integration of this global biomarker into diagnostic workflows is hampered by the limitations of current 5-hmC quantification methods. Here we present and validate a fluorescence-based platform for high-throughput and cost-effective quantification of global genomic 5-hmC levels. We utilized the assay to characterize cancerous tissues based on their 5-hmC content, and observed a pronounced reduction in 5-hmC level in various cancer types. We present data for glioblastoma, colorectal cancer, multiple myeloma, chronic lymphocytic leukemia and pancreatic cancer, compared to corresponding controls. Potentially, the technique could also be used to follow response to treatment for personalized treatment selection. We present initial proof-of-concept data for treatment of familial adenomatous polyposis.

Omental Tissue-Mediated Tumorigenesis of Gastric Cancer Peritoneal Metastases.

The peritoneal cavity, especially the omentum, is a common site for gastric cancer metastasis, representing advanced disease stage and poor prognosis. Here, we studied the effects of omental tissue on gastric cancer tumor progression in vitro and in vivo. Utilizing in vitro models, we found that omental tissue secreted factors increased gastric cancer cellular growth (by 30-67%, P < 0.05), motility (>8-fold, P < 0.05), invasiveness (>7-fold, P < 0.05) and chemoresistance to platinum-based chemotherapeutic agents (>1.2-fold for oxaliplatin and >1.6-fold for cisplatin, P < 0.05). Using a robust proteomic approach, we identified numerous molecules secreted into the omental tissue conditioned medium (CM) which may promote gastric cancer cellular aggressiveness (i.e., IL-6, IL-8, MMP9, FN1, and CXCL-5). Next, an in vivo xenograft mouse model showed an increased human gastric adenocarcinoma tumor volume of cells co-cultured with human omental tissue secreted factors; 1.6 ± 0.55 vs. 0.3 ± 0.19 cm3 (P < 0.001), as well as increased angiogenesis. Finally, exosomes were isolated from human omental tissue CM of gastric cancer patients. These exosomes were taken up by gastric cancer cells enhancing their growth (>8-fold, P < 0.01) and invasiveness (>8-fold, P < 0.001). Proteomic analysis of the content of these exosomes identified several established cancer- related proteins (i.e., IL-6, IL-8, ICAM-1, CCl2, and OSM). Taken together, our findings imply that the omentum play an active role in gastric cancer metastasis. The data also describe specific cytokines that are involved in this cross talk, and that omental tissue- derived exosomes may contribute to these unique cellular interactions with gastric cancer cells. Further studies aimed at understanding the biology of gastric cancer intra peritoneal spread are warranted. Hopefully, such data will enable to develop future novel therapeutic strategies for the treatment of metastatic gastric cancer.

MicroRNA profiling of pancreatic ductal adenocarcinoma (PDAC) reveals signature expression related to lymph node metastasis.

Lymph node (LN) metastasis occurs frequently in pancreatic ductal adenocarcinoma (PDAC), representing an advanced disease stage and independently predicting patient survival. Current nodal staging is inadequate preoperatively and even less so postoperatively, and molecular biomarkers are needed to improve prognostication and selection of therapy. Recent data have suggested important roles of miRNAs in PDAC tumorigenesis and progression. The aim of the present study was to identify miRNA expression signature for nodal spread in PDAC patients. Using PDAC human tissue specimens, we identified 39 miRNAs which were differently expressed in LN positive compared to LN negative PDAC samples. Of them, six miRNAs have been reported to play a role in cancer invasion and metastasis. A high versus low six- miRNA signature score was predictive of LN metastasis in the PDAC validation cohort. We demonstrated a similar expression pattern of four out of the six miRNAs in the plasma of PDAC patients. The results of our in-vitro studies revealed that miR-141 and miR-720 are involved in the process of epithelial to mesenchymal-transition in PDAC. These miRNAs significantly inhibited in vitro proliferation, migration and invasion of PDAC cells as evidence by gain- and loss- of function studies, specifically, via ZEB-1 and TWIST1 transcription factors, as well as through the activation of the MAP4K4/JNK signaling pathway.

Unique cellular interactions between pancreatic cancer cells and the omentum.

Pancreatic cancer is a common cause of cancer-related mortality. Omental spread is frequent and usually represents an ominous event, leading to patient death. Omental metastasis has been studied in ovarian cancer, but data on its role in pancreatic cancer are relatively scarce and the molecular biology of this process has yet to be explored. We prepared tissue explants from human omental fat, and used conditioned medium from the explants for various in vitro and in vivo experiments designed to evaluate pancreatic cancer development, growth, and survival. Mass spectrometry identified the fat secretome, and mRNA array identified specific fat-induced molecular alternations in tumor cells. Omental fat increased pancreatic cancer cellular growth, migration, invasion, and chemoresistance. We identified diverse potential molecules secreted by the omentum, which are associated with various pro-tumorigenic biological processes. Our mRNA array identified specific omental-induced molecular alternations that are associated with cancer progression and metastasis. Omental fat increased the expression of transcription factors, mRNA of extracellular matrix proteins, and adhesion molecules. In support with our in vitro data, in vivo experiments demonstrated an increased pancreatic cancer tumor growth rate of PANC-1 cells co-cultured for 24 hours with human omental fat conditioned medium. Our results provide novel data on the role of omental tissue in omental metastases of pancreatic cancer. They imply that omental fat secreted factors induce cellular reprogramming of pancreatic cancer cells, resulting in increased tumor aggressiveness. Understanding the mechanisms of omental metastases may enable us to discover new potential targets for therapy.

Adipose-Induced Retroperitoneal Soft Tissue Sarcoma Tumorigenesis: A Potential Crosstalk between Sarcoma and Fat Cells.

Previous data demonstrated that high retroperitoneal visceral fat content increases retroperitoneal soft-tissue sarcoma (RSTS) local recurrence and patients' mortality. Most RSTS tumors initiate and recur within visceral fat. The objective of the current study was to evaluate potential paracrine effects of visceral fat on RSTS. A xenograft model was used to evaluate in vivo effects of human visceral fat on STS growth. Tissue explants were prepared from visceral fat, and their conditioned medium (CM) was utilized for various in vitro experiments designed to evaluate growth, survival, migration, and invasion of STS and endothelial cells. Visceral fat-secreted protumorigenic factors were identified by mass spectrometry. The in vivo experiments demonstrated a significant increase in STS tumor growth rate when SK-LMS-1 leiomyosarcoma cells were colocalized with human visceral fat compared with subcutaneous injection of cancer cells only. The in vitro model demonstrated that visceral fat CM increased STS cellular growth and reduced doxorubicin-induced apoptosis. Visceral fat also enhanced STS cellular migration and invasion. In addition, visceral fat CM significantly increased endothelial cell tube formation, suggesting its role as a proangiogenic factor in the STS tumor microenvironment (TME). Using a robust proteomic approach, liquid chromatography and tandem mass spectrometry resolved various molecules within the visceral fat CM, of which a subset was associated with protumorigenic biologic processes. These results suggest that visceral fat directly interacts with STS cells by secreting specific adipokines into the TME, thus augmenting STS tumor cell proliferation and invasiveness. Fat-induced STS molecular deregulations should be studied to identify new potential prognostic and therapeutic targets. IMPLICATIONS: Visceral fat induces protumorigenic effects, in STS, through various secreted factors that should be investigated to improve our understanding of adipose-cancer cell interactions. Mol Cancer Res; 14(12); 1254-65. ©2016 AACR.

Epithelial-to-mesenchymal transition (EMT) in intraductal papillary mucinous neoplasm (IPMN) is associated with high tumor grade and adverse outcomes.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) is generally associated with increased tumor aggressiveness and poor prognosis. We evaluated EMT characteristics in intraductal papillary mucinous neoplasm (IPMN) tumor specimens and their potential role as biomarkers for malignancy, metastasis, and adverse patient outcomes. METHODS: IPMN surgical specimens were identified and reviewed by two gastrointestinal pathologists. Immunohistochemical analysis of E-cadherin, vimentin, and ZEB-1 was performed. Samples were linked to clinicopathologic and outcome data for these patients. Western blot test was used to evaluate ZEB-1 expression in IPMN samples; 846 human miRNAs were profiled, and EMT-related differentially expressed miRNAs were validated using quantitative real-time polymerase chain reaction. RESULTS: Fifty-eight IPMN specimens and five normal pancreatic tissue samples were immunohistochemically stained and scored. E-cadherin expression was significantly lower in malignant versus low-grade IPMN (p < 0.05). Vimentin expression was increased in malignant IPMN tumor samples (p < 0.05). EMT was associated with increased lymph node metastasis and decreased survival of malignant IPMN patients (p < 0.05). ZEB-1, an imperative EMT regulator, was exclusively expressed by malignant IPMN tumors. miRNA hierarchical clustering demonstrated grouping of two main IPMN subgroups: low-grade IPMN versus high-grade IPMN and carcinoma. Twenty-four miRNAs were differentially expressed (14 up-regulated, 10 down-regulated). The EMT-regulatory miRNAs, miR-200c and miR-141, were down-regulated (twofold and 1.8-fold decrease, respectively) in malignant versus low-grade IPMN (p < 0.05). CONCLUSIONS: EMT may play a role in IPMN tumorigenesis and metastasis. EMT molecular deregulations could be utilized as potential novel biomarkers for the identification of high-risk IPMN patients.

MicroRNA expression signatures in intraductal papillary mucinous neoplasm of the pancreas.

BACKGROUND: Intraductal papillary mucinous neoplasms (IPMN) represent a spectrum of tumors that range from low-grade (LG) dysplastic tumors to invasive cancer. Identification of IPMN at high risk for malignant transformation is important for the prevention and early treatment of pancreatic cancer. The roles of microRNA expression in the development of IPMN have not been extensively evaluated. METHODS: Expression patterns of 846 human microRNAs (miRNAs) was analyzed using microRNA microarray in 55 tissues, including LG IPMN (n = 10), moderate-grade (MG) IPMN (n = 5), high-grade (HG) IPMN (n = 5), invasive cancer with IPMN (IPMC; n = 10), pancreatic ductal adenocarcinoma without IPMN (PDA; n = 5), LG IPMN extracted from specimens that contain IPMC (LG_Ca; n = 10), and normal pancreatic tissues (n = 10). RESULTS: Fourteen miRNAs were differentially expressed in all IPMN tissues compared with normal pancreatic tissue. Expression level of 3 miRNAs was proportional to dysplasia level. Hierarchical clustering demonstrated grouping of 2 IPMN subgroups: LG and MG IPMN verses HG IPMN and IPMC. Expression of 15 miRNAs was significantly different between these groups. LG_Ca tissues clustered with the HG IPMC group, and 12 miRNAs were differentially expressed in LG_Ca, HG lesions, and IPMC compared with LG lesions. The expression patterns of selected miRNAs were validated using quantitative reverse-transcription real-time polymerase chain reaction. Hierarchical clustering demonstrated microRNA expression profile in IPMC was significantly different from PDA, suggesting that different pathways are involved in these cancer types. CONCLUSION: This study demonstrates that miRNAs are involved in the development and progression of IPMN. We identified potential targets for diagnosis, prognostication, and treatment of IPMN.

Inhibition of hepatitis C virus RNA replicons by peptide aptamers.

BACKGROUND/AIMS: Hepatitis C virus infection is a major worldwide health problem, causing chronic hepatitis, cirrhosis and primary liver cancer. In addition to its role in the viral polyprotein-processing, the viral NS3 serine protease has been implicated in interactions with various cell constituents resulting in phenotypic changes including malignant transformation. NS3 is currently regarded a prime target for anti-viral drugs thus specific inhibitors of its activities should be important. With the aim of inhibiting NS3 protease activity as a means to inhibit HCV replication we used a novel bacterial genetic screen to isolate NS3-inhibiting peptide aptamers. METHODS: We have isolated and characterized seven NS3-inhibiting peptide aptamers. We investigated the phenotypic changes that SEAP-secreting subgenomic RNA replicons undergo upon intracellular expression of these peptide aptamers, assayed by real-time RT-PCR and inhibition of SEAP secretion by transfected replicon cells. RESULTS AND CONCLUSIONS: The peptide aptamers inhibited NS3 protease activity in vitro with an IC50 in the low micromolar range. Upon transfection, aptamers inhibited the replication of SEAP-secreting genotype 1b subgenomic RNA replicons. Aptamer-based intracellular immunization may emerge as a promising antiviral approach to interfere with the life cycle and pathogenicity of HCV.

A universal strategy for stable intracellular antibodies.

The expression of intracellular antibodies (intrabodies) in mammalian cells has provided a powerful tool to manipulate microbial and cellular signalling pathways in a highly precise manner. However, several technical hurdles have thus far restricted their more widespread use. In particular, single-chain antibodies (scFvs) have been reported to fold poorly in the reducing environment of the cytoplasm and as such there has been a reluctance to use scFv-phage libraries as a source of intrabodies unless a preselection step was applied to identify these rare scFvs that could fold properly in the absence of disulfide bonds. Recently, we reported that scFvs can be efficiently expressed within the cytoplasm of bacteria when fused at the C-terminus of the Escherichia coli maltose-binding protein (MBP). Here, we demonstrate that such MBP-scFvs are similarly stabilized when expressed in the mammalian cell cytoplasm as well as other compartments. This was demonstrated by comparing MBP-scFv fusions to the corresponding unfused scFvs that activate a defective beta-galactosidase enzyme, others that neutralize the wild-type beta-galactosidase enzyme, and an antibody that blocks the epidermal growth factor receptor. In all cases, the MBP-scFvs significantly outperformed their unfused counterparts. Our results suggest that fusion of scFvs to MBP, and possibly to other "chaperones in the context of a fusion protein", may provide a universal approach for efficient expression of intrabodies in the mammalian cell cytoplasm. This strategy should allow investigators to bypass much of the in vitro scFv characterization that is often not predictive of in vivo intrabody function and provide a more efficient use of large native and synthetic scFv-phage libraries already in existence to identify intrabodies that will be active in vivo.