Qi Qin

MiR-130b Is a Prognostic Marker and Inhibits Cell Proliferation and Invasion in Pancreatic Cancer through Targeting STAT3

Accumulating evidence indicates that microRNAs (miRNAs) are aberrantly expressed in human cancer and contribute to the tumorigenesis, but their roles in pancreatic cancer are still largely unknown. In this study, our data showed that miR-130b was significantly downregulated in 52 pairs of pancreatic cancer tissues and five cell lines. Furthermore, the deregulated miR-130b was correlated with worse prognosis, increased tumor size, late TNM stage, lymphatic invasion and distant metastasis. Multivariate analysis showed that miR-130b expression was a significant and independent prognostic predictor for pancreatic cancer patients. Functional studies indicated that the overexpression of miR-130b dramatically suppressed the proliferation of pancreatic cancer cells both in vitro and in vivo, which could be attributed to the induction of apoptosis and cell cycle arrest at S phase. Meanwhile, an overexpressed miR-130b remarkably inhibited the invasive ability of pancreatic cancer cells. Moreover, the dual luciferase assay revealed that STAT3 was directly targeted by miR-130b, which was further confirmed by the inverse expression of miR-130b and STAT3 in pancreatic cancer samples. Our findings suggested that miR-130b might have a considerable potential in prognosis identification and application of therapy for pancreatic cancer.

miRNA-141, Downregulated in Pancreatic Cancer, Inhibits Cell Proliferation and Invasion by Directly Targeting MAP4K4

miRNAs are associated with various types of cancer due to their ability to affect expression of genes that modulate tumorigenesis. In this study, we explored the role of miR-141 in pancreatic cancer. The analysis of clinical characteristics showed that miR-141 was significantly downregulated in tissues and cell lines of pancreatic cancer. Moreover, the decreased miR-141 level was significantly associated with tumor size and TNM stage, as well as lymph node and distant metastasis. Meanwhile, both Kaplan–Meier and multivariate survival analysis showed decreased miR-141 were associated with overall survival. Overexpression of miR-141 in pancreatic cancer cells inhibited cell proliferation, clonogenicity, and invasion; induced G1 arrest and apoptosis; and enhanced chemosensitivity. To understand how miR-141 mediates the phenotype of pancreatic cancer cells, a bioinformatics tool was used to identify MAP4K4 as a potential target of miR-141. The Dual-Luciferase reporter gene assay showed that miR-141 binds directly to the 3′-untranslated region (3′UTR) of MAP4K4 to inhibit MAP4K4 expression. Western blot and quantitative real-time PCR (qRT-PCR) analyses revealed that MAP4K4 expression was inversely correlated with miR-141 expression both in pancreatic cancer samples and cell lines. Knockdown of MAP4K4 inhibited cell proliferation, clonogenicity, and invasion, induced G1 arrest and apoptosis, and enhanced chemosensitivity. In a nude mouse xenograft model, both overexpression of miR-141 and knockdown of MAP4K4 significantly repressed pancreatic cancer cell growth. Therefore, we conclude that miR-141 targets MAP4K4, acts as a tumor suppressor in pancreatic cancer cells, and may serve as a novel therapeutic agent for miRNA-based pancreatic cancer therapy. Mol Cancer Ther; 12(11); 2569–80. ©2013 AACR.

MiR-148b functions as a tumor suppressor in pancreatic cancer by targeting AMPKα1

miRNAs are small noncoding RNAs that participate in a variety of biologic processes, and dysregulation of miRNA is always associated with cancer development and progression. Aberrant expression of miR-148b has been found in some types of cancer, but its expression and potential biologic role in pancreatic cancer are still largely unknown. In this study, our data showed that miR-148b was significantly downregulated in 48 pairs of human pancreatic cancer tissues and five cell lines. Furthermore, the deregulated miR-148b was correlated with increased tumor size, late tumor–node–metastasis stage, lymphatic invasion, distant metastasis, and worse prognosis in pancreatic cancer. Functional studies indicated overexpression of miR-148b dramatically suppressed the growth of cancer cells, attributable to induction of apoptosis and cell-cycle arrest at S-phase. Meanwhile, miR-148b remarkably inhibited invasion and enhanced chemosensitivity of pancreatic cancer cells. Moreover, ectopic expression of miR-148b was able to inhibit tumorigenicity in nude mice. Further studies revealed that AMPKα1 might be the direct target gene of miR-148b, and overexpressed AMPKα1 inversely correlated with miR-148b in pancreatic cancer. Silencing of AMPKα1 with RNA interference inhibited the growth of pancreatic cancer cells in vitro and in vivo and also induced apoptosis, cell-cycle arrest, and inhibited invasion of cancer cells, which is consistent with the effects of miR-148b overexpression. In conclusion, miR-148b can inhibit cell proliferation, invasion, and enhance chemosensitivity of pancreatic cancer by targeting AMPKα1. Our present results implicate the potential effects of miR-148b on prognosis and treatment of pancreatic cancer. Mol Cancer Ther; 12(1); 83–93. ©2012 AACR.

SIRT1 RNAi knockdown induces apoptosis and senescence, inhibits invasion and enhances chemosensitivity in pancreatic cancer cells.

The NAD+-dependent deacetylase, sirtuin 1 (SIRT1), has been recently been suspected to have a role in tumorigenesis. We investigated the expression of SIRT1 in pancreatic cancer and the effect of SIRT1-targeted RNA interference (RNAi) on cell proliferation and tumor formation in a pancreatic cancer cell line, PANC1. The expression of SIRT1 was investigated in 49 specimens of pancreatic cancer and adjacent normal pancreatic tissues. SIRT1 was overexpressed in pancreatic cancer tissues at both the mRNA and protein levels, with increased SIRT1 positivity associated with tumors from patients over 60 years old, tumors larger than 4 cm, higher TNM (extent of tumor (T), the extent of spread to lymph nodes (N), and presence of distant metastasis (M)) stage or the presence of lymph node or hepatic metastases. The PANC-1 was stably transfected with a SIRT1 small hairpin RNA (shRNA) expression plasmid and compared with untransfected and PANC-1-negative RNAi cells. Proliferation of PANC-1–SIRT1–RNAi cells was significantly reduced, accompanied by increased rates of apoptosis, G1 arrest and senescence. Furthermore, FOXO3a expression was markedly upregulated in PANC-1–SIRT1–RNAi cells, but no significant difference in p53 expression was observed. The invasive ability of PANC-1–SIRT1–RNAi cells was markedly reduced in vitro, which was linked to increased E-cadherin and reduced-MMP expression. Additionally, PANC-1–SIRT1–RNAi cells had a significantly reduced capacity to form tumors in vivo compared with untransfected and PANC-1-negative RNAi cells. These results suggest that SIRT1 may promote cell proliferation and tumor formation in pancreatic cancer, and downregulation of SIRT1 using shRNA could provide a novel therapeutic treatment.

Chronic pancreatitis and pancreatic cancer demonstrate active epithelial–mesenchymal transition profile, regulated by miR-217-SIRT1 pathway

Epithelial-mesenchymal transition (EMT) is supposed to be an inflammation induced response which may take a central role in tumorigenesis. Since recent evidence indicates that microRNAs may be involved in EMT, the present study set out to reveal the miRNA which might regulate the EMT in CP (chronic pancreatitis) and PC (pancreatic cancer) and its potential mechanism. Firstly, we provided evidence that both CP and PC tissues demonstrated active EMT profile. Consistently, miR-217 was obviously down-regulated in CP, PC and TGF-β1 treated PC cells, while negatively correlated to its direct target SIRT1. Moreover, either ectopic expression of miR-217 or inhibition of SIRT1 remarkably induced mesenchymal to epithelial transition (MET) in TGF-β1 treated PC cells. On the contrary, miR-217 inhibitor promoted EMT in PC cells but not in SIRT-knockdown PC cells. Clinical information from a cohort of 54 PC patients demonstrated that down-regulated miR-217 was positively correlated with late tumor stage, lymphatic invasion, vascular infiltration and distant metastasis. These results suggest that the overexpressed TGF-β1 in inflammation triggers the deregulation of the miR-217-SIRT1 pathway and then promotes the EMT process, which might be involved in the tumorigenesis of PC. Additionally, miR-217 may function as a novel target and predictor for PC prevention and therapy.

Effects of different resuscitation fluid on severe acute pancreatitis

AIM To compare effects of different resuscitation fluid on microcirculation, inflammation, intestinal barrier and clinical results in severe acute pancreatitis (SAP). METHODS One hundred and twenty patients with SAP were enrolled at the Pancreatic Disease Institute between January 2007 and March 2010. The patients were randomly treated with normal saline (NS group), combination of normal saline and hydroxyethyl starch (HES) (SH group), combination of normal saline, hydroxyethyl starch and glutamine (SHG group) in resuscitation. The ratio of normal saline to HES in the SH and SHG groups was 3:1. The glutamine (20% glutamine dipeptide, 100 mL/d) was supplemented into the resuscitation liquid in the SHG group. Complications and outcomes including respiratory and abdominal infection, sepsis, abdominal hemorrhage, intra-abdominal hypertension, abdominal compartment syndrome (ACS), renal failure, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), operation intervention, length of intensive care unit stay, length of hospital stay, and mortality at 60 d were compared. Moreover, blood oxygen saturation (SpO2), gastric intramucosal pH value (pHi), intra-abdominal pressure (IAP), inflammation cytokines, urine lactulose/mannitol (L/M) ratio, and serum endotoxin were investigated to evaluate the inflammatory reaction and gut barrier. RESULTS Compared to the NS group, patients in the SH and SHG groups accessed the endpoint more quickly (3.9 ± 0.23 d and 4.1 ± 0.21 d vs 5.8 ± 0.25 d, P < 0.05) with less fluid volume (67.26 ± 28.53 mL/kg/d, 61.79 ± 27.61 mL/kg per day vs 85.23 ± 21.27 mL/kg per day, P < 0.05). Compared to the NS group, incidence of renal dysfunction, ARDS, MODS and ACS in the SH and SHG groups was obviously lower. Furthermore, incidence of respiratory and abdominal infection was significantly decreased in the SH and SHG groups, while no significant difference in sepsis was seen. Moreover, less operation time was needed in the SH and SHG group than the NS group, but the difference was not significant. The mortality did not differ significantly among these groups. Blood SpO2 and gastric mucosal pHi in the SH and SHG groups increased more quickly than in the NS group, while IAP was significantly decreased in the SH and SHG group. Moreover, the serum tumor necrosis factor-α, interleukin-8 and C-reactive protein levels in the SH and SHG groups were obviously lower than in the NS group at each time point. Furthermore, urine L/M ratio and serum endotoxin were significantly lower in the SH group and further decreased in the SHG group. CONCLUSION Results indicated that combination of normal saline, HES and glutamine are more efficient in resuscitation of SAP by relieving inflammation and sustaining the intestinal barrier.

Mechanical stiffness of liver tissues in relation to integrin β1 expression may influence the development of hepatic cirrhosis and hepatocellular carcinoma.

Increased rigidity of the extracellular matrix (ECM) is commonly associated with hepatocellular carcinoma (HCC). The purpose of this study was to quantitate the mechanical stiffness of various hepatic tissues, evaluate integrin β1 expression, and investigate the correlation between these two factors in the development of HCC.

Ectopic expression of miR-494 inhibited the proliferation, invasion and chemoresistance of pancreatic cancer by regulating SIRT1 and c-Myc.

Recent researches demonstrate that microRNAs (miRNAs) are deregulated in numerous cancers and involved in tumorigenesis, whereas their influences on pancreatic cancer (PC) still need further elucidation. The present research revealed that miR-494 was significantly decreased in PC cell lines and tissues. Functional study showed that overexpressed miR-494 could remarkably inhibit proliferation of PC cells both in vitro and in vivo, which was due to induction of apoptosis, G1-phase arrest and senescence. Moreover, upregulated miR-494 significantly prohibited invasion of PC cells. Meanwhile, both c-Myc and SIRT1 was identified as targets of miR-494 through dual luciferase assay and further confirmed by the reverse correlation between miR-494 and c-Myc/SIRT1 in PC samples. Furthermore, co-transfection with c-Myc-RNAi and SIRT1-RNAi synergistically reduced c-Myc and SIRT1 expression, and inhibited proliferation of PC, which simulated the effects of miR-494 overexpression. On the contrary, co-overexpression of c-Myc and SIRT1 effectively rescued inhibition of overexpressed miR-494 on PC cells. The clinical characteristics further revealed that low miR-494 correlated with larger tumor size, late tumor node metastasis stage, lymphatic invasion, distant metastasis and poor prognosis. In conclusion, the present study indicated that miR-494 might serve as predictor and inhibitor in PC by directy downregulating the loop of c-Myc and SIRT1.

Nicotinamide prohibits proliferation and enhances chemosensitivity of pancreatic cancer cells through deregulating SIRT1 and Ras/Akt pathways

BACKGROUND Nicotinamide (NAM), the precursor for the synthesis of NAD(+) and also an inhibitor of SIRT1, has been discovered to inhibit some types of cancer. However, little is known about the effects of NAM on pancreatic cancer cells. Since previous research showed that SIRT1 and K-Ras/Akt signaling acted as a promoter in tumorigenesis of pancreatic cancer, our present research set out to explore whether NAM inhibits proliferation and facilitates chemosensitivity in pancreatic cancer cells as well as the potential mechanisms involving SIRT1 and K-Ras/Akt pathway. METHODS Cell viability was assessed by MTT assay, and apoptosis and cell cycle were measured by flow cytometry. Cell invasive ability was evaluated by matrigel invasion assays. The activity of SIRT1 was measured by the Fluor de Lys deacetylation assay. Expression levels of SIRT1, K-Ras, Phosphated Akt (P-Akt, Ser-473) and Akt were measured using western blot. In vivo tumor growth was performed in pancreatic cancer cells xenografts. RESULTS NAM inhibited the proliferation of pancreatic cancer cells in a dose-dependent manner, and significantly induced apoptosis and cell cycle arrest in G2/M phase. Moreover, NAM obviously restrained cell invasive ability and increased the chemosensitivity. NAM significantly inhibited the activity of SIRT1 and decreased expression of SIRT1, K-Ras and P-Akt. Further, NAM prohibited proliferation and enhanced GEM antitumor activity in vivo. CONCLUSIONS Our results implied that NAM might be a potential therapeutic agent for human pancreatic cancer treatment through downregulating SIRT1, K-Ras and P-Akt expression.

High risk factors of pancreatic carcinoma

SummaryOver the past decades, cancer has become one of the toughest challenges for health professionals. The epidemiologists are increasingly directing their research efforts on various malignant tumor worldwide. Of note, incidence of cancers is on the rise more quickly in developed countries. Indeed, great endeavors have to be made in the control of the life-threatening disease. As we know it, pancreatic cancer (PC) is a malignant disease with the worst prognosis. While little is known about the etiology of the PC and measures to prevent the condition, so far, a number of risk factors have been identified. Genetic factors, pre-malignant lesions, predisposing diseases and exogenous factors have been found to be linked to PC. Genetic susceptibility was observed in 10% of PC cases, including inherited PC syndromes and familial PC. However, in the remaining 90%, their PC might be caused by genetic factors in combination with environmental factors. Nonetheless, the exact mechanism of the two kinds of factors, endogenous and exogenous, working together to cause PC remains poorly understood. The fact that most pancreatic neoplasms are diagnosed at an incurable stage of the disease highlights the need to identify risk factors and to understand their contribution to carcinogenesis. This article reviews the high risk factors contributing to the development of PC, to provide information for clinicians and epidemiologists.