PIK3R3 Promotes Metastasis of Pancreatic Cancer via ZEB1 Induced Epithelial-Mesenchymal Transition.

BACKGROUND/AIMS: PIK3R3 is a regulatory subunit of phosphatidylinositol 3-kinase (PI3K) which plays an essential role in the metastasis of several types of cancer. However, whether PIK3R3 can promote the metastasis of pancreatic cancer (PC) is still unclear. In this study, we characterized the role of PIK3R3 in metastasis of PC and underlying potential mechanisms. METHODS: RT-PCR, western blot, immunofluorescence (IF) and immunohistochemistry (IHC) were applied to investigate the expression of genes and proteins in different cell lines and tissues. To assess the function of PIK3R3 and related mechanisms, the cells with RNAi-mediated knockdown or overexpression were used to perform a series of in vitro and in vivo assays. RESULTS: PIK3R3 was significantly overexpressed in pancreatic cancer tissues, especially in metastatic cancer tissues, as well as in pancreatic cancer cells. Functional assays suggested that overexpression or knockdown of PIK3R3 could respectively promote or suppress the migration and invasion of PC cells in vitro and in vivo. Further mechanism related studies demonstrated that ERK1/2-ZEB1 pathway-triggered epithelial-mesenchymal transition (EMT) might be responsible for the PIK3R3-induced PC cell migration and invasion. CONCLUSION: PIK3R3 could promote the metastasis of PC by facilitating ZEB1 induced EMT, and could act as a potential therapeutic target to limit PC metastasis.

A Yin-Yang 1/miR-30a regulatory circuit modulates autophagy in pancreatic cancer cells.

BACKGROUND: Autophagy is a highly regulated biological process that mediates the degradation of intracellular components. It is required for tumor cell metabolism and homeostasis. Yin-Yang 1 (YY1) has been reported to be involved in autophagy in several carcinomas. However, its role in autophagy in pancreatic cancer, one of the deadliest human malignancies, is unknown. Here, we investigated the function of YY1 in pancreatic cancer cells autophagy and its mechanisms of action. METHODS: The activity of cells undergoing autophagy was assessed using transmission electron microscopy, immunofluorescence, and Western blotting. A luciferase activity assay, real-time quantitative polymerase chain reaction (RT-qPCR), and chromatin immunoprecipitation (ChIP) were also used to identify putative downstream targets of YY1. RESULTS: YY1 was confirmed to regulate autophagy in pancreatic cancer cells. It was found to directly regulate the expression of miR-30a, a known modulator of autophagy-associated genes. Furthermore, overexpression of miR-30a attenuated the pro-autophagic effects of YY1. CONCLUSIONS: Cumulatively, our data suggest that miR-30a acts in a feedback loop to modulate the pro-autophagic activities of YY1. Thus, autophagy in pancreatic cancer cells may be regulated, in part, by a tightly coordinated YY1/miR-30a regulatory circuit. These findings provide a potential druggable target for the development of treatments for pancreatic cancer.

Yin Yang-1 suppresses invasion and metastasis of pancreatic ductal adenocarcinoma by downregulating MMP10 in a MUC4/ErbB2/p38/MEF2C-dependent mechanism.

BACKGROUND: Increasing evidence indicates an important role of transcription factor Yin Yang-1 (YY1) in human tumorigenesis. However, its function in cancer remains controversial and the relevance of YY1 to pancreatic ductal adenocarcinoma (PDAC) remains to be clarified. METHODS: In this study, we detected YY1 expression in clinical PDAC tissue samples and cell lines using quantitative RT-PCR, immunohistochemistry and western blotting. We also detected MUC4 and MMP10 mRNA levels in 108 PDAC samples using qRT-PCR and analyzed the correlations between YY1 and MUC4 or MMP10 expression. The role of YY1 in the proliferation, invasion and metastatic abilities of PDAC cells in vitro was studied by CCK-8 assay, cell migration and invasion assays. In vivo pancreatic tumor growth and metastasis was studied by a xenogenous subcutaneously implant model and a tail vein metastasis model. The potential mechanisms underlying YY1 mediated tumor progression in PDAC were explored by digital gene expression (DGE) sequencing, signal transduction pathways blockage experiments and luciferase assays. Statistical analysis was performed using the SPSS 15.0 software. RESULTS: We found that the expression of YY1 in PDACs was higher compared with their adjacent non-tumorous tissues and normal pancreas tissues. However, PDAC patients with high level overexpression of YY1 had better outcome than those with low level overexpression. YY1 expression levels were statistically negatively correlated with MMP10 expression levels, but not correlated with MUC4 expression levels. YY1 overexpression suppressed, whereas YY1 knockdown enhanced, the proliferation, invasion and metastatic properties of BXPC-3 cells, both in vitro and in vivo. YY1 suppresses invasion and metastasis of pancreatic cancer cells by downregulating MMP10 in a MUC4/ErbB2/p38/MEF2C-dependent mechanism. CONCLUSIONS: The present study suggested that YY1 plays a negative role, i.e. is a tumor suppressor, in PDAC, and may become a valuable diagnostic and prognostic marker of PDAC.

Elevation of MMP-9 and IDO induced by pancreatic cancer cells mediates natural killer cell dysfunction.

BACKGROUND: Natural killer (NK) cells play a key role in non-specific immune response in different cancers, including pancreatic cancer. However the anti-tumor effect of NK cells decreases during pancreatic cancer progression. The regulatory pathways by which NK cells facilitate tumor immune escape are unclear, therefore our purpose was to investigate the roles of the contributory factors. METHODS: NK cells isolated from fresh healthy peripheral blood were co-cultured with normal human pancreatic ductal cells hTERT-HPNE and human pancreatic cancer cell lines SW1990 and BxPc-3 in vitro. Then NK cell function was determined by Flow cytometric analysis of surface receptors and cytotoxic granules in NK cells, NK cell apoptosis and cytotoxicity, and Enzyme-linked immunosorbent assay of cytokines. Expression level of MMP-9, IDO and COX-2 in hTERT-HPNE and SW1990 cells were detected by quantitative RT-PCR. Statistical differences between data groups were determined by independent t-tests using SPSS 19.0 software. RESULTS: Our results showed that NK cell function was significantly downregulated following exposure to pancreatic cancer cells compared to normal pancreatic cells, as demonstrated by lower expressions of activating surface receptors (NKG2D, DNAM-1, NKp30 and NKp46) and cytotoxic granules (Perforin and Granzyme B); decreased secretion of cytokines (TNF-α and IFN-γ); and reduced cytotoxicity against myelogenous leukemia K562 cells. Further investigations revealed that MMP-9 and IDO may be implicated in SW1990 cell-induced NK cell dysfunction by facilitating tumor immune evasion. Blockade by TIMP-1 and/or 1-MT could partially restore NK function. CONCLUSIONS: Taken together, elevation of MMP-9 and IDO induced by pancreatic cancer cells mediates NK cell dysfunction. Our findings could contribute to the development of NK cell-based immunotherapy in patients with pancreatic cancer.

Comprehensive analysis of the percentage of surface receptors and cytotoxic granules positive natural killer cells in patients with pancreatic cancer, gastric cancer, and colorectal cancer.

BACKGROUND: Digestive malignancies, especially pancreatic cancer (PC), gastric cancer (GC), and colorectal cancer (CRC), still occur at persistently high rates, and disease progression in these cancers has been associated with tumor immunosurveillance escape. Natural killer (NK) cell dysfunction may be responsible for this phenomenon, however, the exact relationship between tumor immunosurveillance escape in digestive malignancies and NK cell dysfunction remains unclear. METHODS: Percentage of the surface receptors NKG2A, KIR3DL1, NKG2D, NKp30, NKp44, NKp46, and DNAM-1, as well as the cytotoxic granules perforin and granzyme B positive NK cells were determined in patients with pancreatic cancer (n=31), gastric cancer (n=31), and CRC (n=32) prior to surgery and healthy controls (n=31) by multicolor flow cytometry. Independent t-tests or Mann-Whitney U-tests were used to compare the differences between the patient and healthy control groups, as well as the differences between patients with different pathologic features of cancer. RESULTS: Percentage of NKG2D, NKp30, NKp46, and perforin positive NK cells was significantly down-regulated in patients with PC compared to healthy controls, as well as GC and CRC; reduced levels of these molecules was associated with indicators of disease progression in each malignancy (such as histological grade, depth of invasion, lymph node metastasis). On the contrary, percentage of KIR3DL1 positive NK cells was significantly increased in patients with PC, as well as GC and CRC, but was not associated with any indicators of disease progression. CONCLUSIONS: Altered percentage of surface receptors and cytotoxic granules positive NK cells may play a vital role in tumor immunosurveillance escape by inducing NK cell dysfunction in patients with PC, GC, and CRC.

Transcriptional regulation of human MUC4 gene: identification of a novel inhibitory element and its nuclear binding protein.

The human mucin 4 (MUC4) is aberrantly expressed in pancreatic adenocarcinoma and tumor cell lines, while remaining undetectable in normal pancreas, indicating its important role in pancreatic cancer development. Although its transcriptional regulation has been investigated in considerable detail, some important elements remain unknown. The aim of the present study was to demonstrate the existence of a novel inhibitory element in the MUC4 promoter and characterize some of its binding proteins. By luciferase reporter assay, we located the inhibitory element between nucleotides -2530 and -2521 in the MUC4 promoter using a series of deletion and mutant reporter constructs. Electrophoretic mobility shift assay (EMSA) with Bxpc-3 cell nuclear extracts revealed that one protein or protein complex bind to this element. The proteins binding to this element were purified and identified as Yin Yang 1 (YY1) by mass spectrometry. Supershift assay and chromatin immunoprecipitation (ChIP) assay confirmed that YY1 binds to this element in vitro and in vivo. Moreover, transient YY1 overexpression significantly inhibited MUC4 promoter activity and endogenous MUC4 protein expression. In conclusion, we reported here a novel inhibitory element in the human MUC4 promoter. This provides additional data on MUC4 gene regulation and indicates that YY1 may be a potential target for abnormal MUC4 expression.

Clinical benefits of a modified Cryopiece system for cryopreservation of rare ejaculated and testicular spermatozoa for ICSI.

Cryopreservation of rare testicular-retrieved spermatozoa for intracytoplasmic sperm injection (ICSI) in patients with severe oligozoospermia and azoospermia remains a major challenge in clinical practice. This study evaluated the Cryopiece system as a potential technique to cryopreserve rare human spermatozoa for ICSI. Small numbers of ejaculated (24 patients) and testicular (13 patients) spermatozoa were cryopreserved using the Cryopiece system. The total number of recovered spermatozoa and motility were assessed after thawing. Thirty-seven couples underwent ICSI using spermatozoa cryopreserved by the Cryopiece system, and ICSI outcomes (rates of fertilization, embryo cleavage, and clinical pregnancy) were evaluated. The average sperm post-thaw retrieval rate was 79.1%, and motility was 29.7%. Ejaculated spermatozoa had a higher post-thaw motility (32.5%) than testicular spermatozoa (21.8%; P = 0.005). ICSI achieved a fertilization rate of 61.9%, embryo cleavage rate of 84.6%, and clinical pregnancy rate of 43.3%. The ICSI outcomes in the ejaculated and testicular frozen-thawed spermatozoa were similar. Assisted oocyte activation (AOA) after ICSI with motile (72.1%) or immotile (71.9%) spermatozoa resulted in a significantly higher fertilization rate than that when using motile spermatozoa without AOA (52.0%; P = 0.005). However, AOA did not enhance the clinical pregnancy rate (55.6% or 40.0% vs 35.3%; P = 0.703). The Cryopiece system is simple and useful for the cryopreservation of small numbers of ejaculated or testicular spermatozoa for ICSI in patients with severe oligozoospermia or nonobstructive azoospermia.

HHLA2 is a novel immune checkpoint protein in pancreatic ductal adenocarcinoma and predicts post-surgical survival.

HHLA2 is a newly identified member of the B7 immune checkpoint family, but its function and crosstalk with immune cells is not fully understood. To gain insights into the HHLA2 expression profile and to determine the clinical significance and function of HHLA2 in pancreatic cancer, we performed immunohistochemistry (IHC) analyses on tissue microarrays (TMAs) of pancreatic ductal adenocarcinoma (PDAC, n = 92) with matched peritumoral tissues as well as in cohorts of precancerous lesions: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). We found that HHLA2 was rarely detected in normal acinar, islet, and ductal cells but widely expressed from early pancreatic precancerous lesions to invasive PDAC. The overall HHLA2 positivity was 95% (19/20) in low grade PanIN and 70.73% (29/41) in IPMN. HHLA2 expression was detected in 77.17% (71/92) of the PDAC cases and was significantly associated with better prognosis in this cohort. Our findings suggest that HHLA2 may behave as a costimulatory ligand in pancreatic cancer, which differs from other B7 family members that are largely characterized as checkpoint inhibitors. Further investigation of the HHLA2 signaling pathway and its receptors is warranted by our data and may lead to novel therapeutic interventions.

Bilateral is superior to unilateral varicocelectomy in infertile males with left clinical and right subclinical varicocele: a prospective randomized controlled study.

PURPOSE: The purpose of this study is to compare the effect of bilateral versus unilateral varicocelectomy on seminal response and spontaneous pregnancy rates in infertile male patients with left clinical and right subclinical varicocele. METHODS: A total of 358 infertile men with left clinical and right subclinical varicocele were randomized to group that underwent bilateral (n = 179) and group that underwent unilateral microsurgical subinguinal varicocelectomy (n = 179). Baseline data regarding male age, female partner age, grade of varicocele body mass index, bilateral testicular volume and serum follicle-stimulating hormone, luteinizing hormone, total testosterone levels and infertility duration and semen parameters were gathered. One year after the surgery, semen parameters including sperm volume, sperm concentration, normal sperm morphology, progressive motility and sperm DNA fragmentation index were recorded and any pregnancy was also documented via telephone calls and hospital visits. RESULTS: We found the baseline characteristics were comparable between the two groups. The seminal parameters had significant improvements 1 year postoperatively in both groups. However, the bilateral group showed significantly greater improvements than the unilateral group in sperm concentration, normal sperm morphology and progressive motility. Besides, the pregnancy rate was statistically higher in the bilateral group after the surgery (42.5 versus 26.0%, bilateral versus unilateral group). CONCLUSION: In conclusion, our study indicated that bilateral is superior to unilateral varicocelectomy in infertile males with left clinical and right subclinical varicocele, which is associated with greater improvements in sperm concentration, normal sperm morphology and progressive motility and spontaneous pregnancy rate after the surgery.

PEG10 overexpression induced by E2F-1 promotes cell proliferation, migration, and invasion in pancreatic cancer.

BACKGROUND: Overexpression of paternally expressed gene-10 (PEG10) is known to promote the progression of several carcinomas, however, its role in pancreatic cancer (PC) is unknown. We investigated the expression and function of PEG10 in PC. METHODS: PEG10 expression and correlation with PC progression was assessed in cancerous tissues and paired non-cancerous tissues. Further, the role of PEG10 in PC cell progression and the underlying mechanisms were studied by using small interfering RNA (Si-RNA). RESULTS: PEG10 expression was significantly higher in cancerous tissues and correlated with PC invasion of vessels and Ki-67 expression. Si-RNA mediated PEG10 knockdown resulted in inhibition of proliferation and G0/G1 cell cycle arrest, which was mediated by p21 and p27 upregulation. A decrease in PC cell invasion and migration, mediated by ERK/MMP7 pathway, was observed in PEG10 knockdown group. Further, findings of ChIP assay suggested that E2F-1 could directly enhance the expression of PEG10 through binding to PEG10 promoter. CONCLUSIONS: In conclusion, PEG10 was identified as a prognostic biomarker for PC and E2F-1 induced PEG10 could promote PC cell proliferation, invasion, and metastasis.

Risk factors of postoperative pancreatic fistula in patients after distal pancreatectomy: a systematic review and meta-analysis.

Postoperative pancreatic fistula (POPF) is a common complication following distal pancreatectomy (DP). However, the risk factors of this complication in patients after DP still remain controversial. The aim of our study is to estimate the association between potential risk factors and POPF. Relevant articles published up to June 21, 2016 were identified via PubMed, EMBASE, Web of Science, and The Cochrane Library. Studies that examined the risk factors of POPF following DP were enrolled. 20 articles (2070 patients) were finally included in this study. The pooled data suggested that patients with soft pancreas, higher Body Mass Index (BMI), blood transfusion, elevated intraoperative blood loss, and longer operative time had a decreased risk for POPF. However, age, gender, malignant pathology, types of stump closure, octreotide therapy, history of diabetes and chronic pancreatitis, splenectomy, multiorgan resection, main duct ligation, preoperative serum albumin levels, PGA felt wrapping, and extended lymphadenectomy could not be regarded as risk factors for POPF. Our analytic data demonstrated that pancreas texture, BMI, blood transfusion, intraoperative blood loss, and operative time were clinical predictor for POPF. This study may assist surgeons to screen patients with high risk of POPF and select appropriate treatment measures.

Yin Yang-1 suppresses pancreatic ductal adenocarcinoma cell proliferation and tumor growth by regulating SOX2OT-SOX2 axis.

The transcription regulator Yin Yang-1 (YY1) serves as a tumor suppressor in pancreatic ductal adenocarcinoma (PDAC). However, the function of YY1 in proliferation of PDAC cells remains to be clarified. In this study, we found that overexpression of YY1 suppressed proliferation and decreased the expression of long non-coding RNA (lncRNA) SOX2OT and its potential target gene SOX2 in PDAC cells. Luciferase reporter, electrophoretic mobility shift (EMSA), and chromatin immunoprecipitation (ChIP) assays revealed binding of YY1 to the SOX2OT promoter. Moreover, YY1 suppressed PDAC cell proliferation through SOX2OT transcriptional inhibition and subsequent decreased SOX2 expression. In addition, YY1 expression was statistically negatively correlated with SOX2OT and SOX2 expression in PDAC tissues and lower level expression of SOX2OT predicted better outcome in PDAC patients. These results confirmed the anti-proliferation effect of YY1 on PDAC cells, which was associated with SOX2 down-regulation in a SOX2OT-dependent mechanism. Although other undiscovered mechanisms may be involved in the YY1-mediated tumor suppression role, the present study suggests that SOX2OT may act as a tumor promotor in PDAC and may represent a valuable diagnostic and therapeutic target.

NIDO, AMOP and vWD domains of MUC4 play synergic role in MUC4 mediated signaling.

MUC4 mucin is well known as an important potential target to overcome pancreatic cancer. Three unique domains (NIDO, AMOP, and vWD) with unclear roles only present in MUC4 but are not found in other membrane-bound mucins. Our previous studies first reported that its splice variant, MUC4/Y can be a model of MUC4 (MUC4 gene fragment is more than 30KB, too huge to clone and eukaryotic express) in pancreatic cancer. More importantly, based on MUC4/Y with the appropriate length of gene sequence, it is easy to construct the unique domain-lacking models of MUC4/Y (MUC4) for research. The present study focuses on investigation of the respective role of the unique NIDO, AMOP, and vWD domain or their synergistic effect on MUC4(MUC4/Y)-mediated functions and mechanisms by series of in vitro assays, sequence-based transcriptome analysis, validation of qRT-PCR & Western blot, and systematic comparative analysis. Our results demonstrate: 1) NIDO, AMOP, and vWD domain or their synergy play significant roles on MUC4/Y-mediated malignant function of pancreatic cancer, downstream of molecule mechanisms, particularly MUC4/Y-triggered malignancy-related positive feedback loops, respectively. 2) The synergistic roles of three unique domains on MUC4/Y-mediated functions and mechanisms are more prominent than the respective domain because the synergy of three domain plays the more remarkable effects on MUC4/Y-mediated signaling hub. Thus, to improve reversed effects of domain-lacking and break the synergism of domains will contribute to block MUC4/Y(MUC4) triggering various oncogenic signaling pathways.

The Expression and Prognostic Roles of MCMs in Pancreatic Cancer.

OBJECTIVES: Minichromosome maintenance (MCM) proteins play important roles in DNA replication by interacting with other factors which participate in the regulation of DNA synthesis. Abnormal over-expression of MCMs was observed in numerous malignancies, such as colorectal cancer. However, the expression of MCMs in pancreatic cancer (PC) was less investigated so far. This study was designed to analyze the expression and prognostic roles of MCM1-10 in PC based on the data provided by The Cancer Genome Atlas (TCGA). METHODS: Pearson χ2 test was applied to evaluate the association of MCMs expression with clinicopathologic indicators, and biomarkers for tumor biological behaviors. Kaplan-Meier plots and log-rank tests were used to assess survival analysis, and univariate and multivariate Cox proportional hazard regression models were used to recognize independent prognostic factors. RESULTS: MCM1-10 were generally expressed in PC samples. The levels of some molecules were markedly correlated with that of biomarkers for S phase, proliferation, gemcitabine resistance. And part of these molecules over-expression was significantly associated with indicators of disease progression, such as depth of tumor invasion and lymph node metastasis. Furthermore, MCM2, 4, 6, 8, and 10 over-expression was remarkably associated with shorter disease free survival time, and MCM2, 4,8, and 10 over-expression was associated with shorter overall survival time. Further multivariate analysis suggested that MCM8 was an independent prognostic factor for PC. CONCLUSION: MCMs abnormal over-expression was significantly associated with PC progression and prognosis. These molecules could be regarded as prognostic and therapeutic biomarkers for PC. The roles of MCMs may be vitally important and the underlying mechanisms need to be furtherinvestigated.

Altered expression of CD226 and CD96 on natural killer cells in patients with pancreatic cancer.

The progression of pancreatic cancer (PC) is significantly associated with tumor immune escape, which may be associated with nature killer (NK) cell dysfunction. CD226, CD96, and TIGIT, which share the ligand CD155, play important roles in the regulation of NK cell function. The present study was conducted to investigate the roles of these molecules in NK cells from PC patients. Expression of these molecules on NK cells was detected from samples of 92 pancreatic cancer patients and 40 healthy controls. The expression of CD155 was also evaluated by immunohistochemistry in 88 pancreatic cancer tissues. The percentage of CD226+ and CD96+ NK cells was significantly lower in PC patients than in the healthy controls; however, the mean fluorescence intensity of CD226 and CD96 was not significantly different between the two groups. TIGIT expression on NK cells from PC patients was similar to that in the healthy controls. Additionally, the expression of CD226 was positively correlated with CD96. Further analysis demonstrated that the decrease in the percentage of CD226+ and CD96+ NK cells was associated with tumor histological grade and lymph node metastasis. Moreover, the CD155 levels in PC tissues were significantly higher than those in adjacent tissues. Our results suggest that a lower percentage of CD226+ and CD96+ NK cells may contribute to tumor immune escape in PC patients; moreover, the use of NK cells with high CD226 and CD96 expression to treat PC cells with high CD155 expression may have potential and should be explored in the future.

Yin Yang-1 increases apoptosis through Bax activation in pancreatic cancer cells.

The transcriptional regulator Yin Yang-1 (YY1) is a tumor suppressor known to be overexpressed in pancreatic cancer. We found that overexpression of YY1 promoted apoptosis and increased the expression and mitochondrial localization of the pro-apoptotic Bax protein in pancreatic cancer cell lines. Luciferase reporter, electrophoretic mobility shift (EMSA), and chromatin immunoprecipitation (ChIP) assays revealed binding of YY1 to the BAX promoter. Moreover, YY1 promoted pancreatic cancer cell apoptosis through Bax transcriptional activation and subsequent translocation of Bax to the mitochondrial membrane, leading to cytochrome c release, and caspase activation.YY1 and BAX are co-expressed in pancreatic cancer tissues and higher BAX expression predicts better outcomes for patients. The ability of YY1 to promote apoptosis in pancreatic cancer cells suggests it may represent a valuable diagnostic and therapeutic target.