HDAC2 promotes loss of primary cilia in pancreatic ductal adenocarcinoma.

Hedgehog (Hh) signaling is deregulated in multiple human cancers including pancreatic ductal adenocarcinoma (PDA). Because KRAS mutation represents one of the earliest genetic alterations and occurs almost universally in PDA, we hypothesized that oncogenic KRAS promotes pancreatic tumorigenesis in part through activation of the Hh pathway. Here, we report that oncogenic KRAS activates hedgehog signaling in PDA cells, utilizing a downstream effector pathway mediated by RAF/MEK/MAPK but not phosphatidylinositol 3-kinase (PI3K)/AKT. Oncogenic KRAS transformation of human pancreatic ductal epithelial cells increases GLI transcriptional activity, an effect that is inhibited by the MEK-specific inhibitors U0126 and PD98059, but not by the PI3K-specific inhibitor wortmannin. Inactivation of KRAS activity by a small interfering RNA specific for oncogenic KRAS inhibits GLI activity and GLI1 expression in PDA cell lines with activating KRAS mutation; the MEK inhibitors U0126 and PD98059 elicit a similar response. In addition, expression of the constitutively active form of BRAF(E600), but not myr-AKT, blocks the inhibitory effects of KRAS knockdown on Hh signaling. Finally, suppressing GLI activity leads to a selective attenuation of the oncogenic transformation activity of mutant KRAS-expressing PDA cells. These results demonstrate that oncogenic KRAS, through RAF/MEK/MAPK signaling, is directly involved in the activation of the hedgehog pathway in PDA cells and that collaboration between these two signaling pathways may play an important role in PDA progression.

Primary cilia are present on human blood and bone marrow cells and mediate Hedgehog signaling.

Primary cilia are microtubule-based solitary membrane projections on the cell surface that play important roles in signaling and development. Recent studies have demonstrated that polarized vesicular trafficking involving the small GTPase Rab8 and its guanine nucleotide exchange factor Rabin8 is essential for primary ciliogenesis. In this study, we show that a highly conserved region of Rabin8 is pivotal for its activation as a guanine nucleotide exchange factor for Rab8. In addition, in its activated conformation, Rabin8 interacts with Sec15, a subunit of the exocyst and downstream effector of Rab8. Expression of constitutively activated Rab8 promotes the association of Sec15 with Rabin8. Using immunofluorescence microscopy, we found that Sec15 co-localized with Rab8 along the primary cilium. Inhibition of Sec15 function in cells led to defects in primary ciliogenesis. The Rabin8-Rab8-Sec15 interaction may couple the activation of Rab8 to the recruitment of the Rab8 effector and is involved in the regulation of vesicular trafficking for primary cilium formation.

Simple SummaryTumors in the pancreas and colon are still too often an unmet clinical problem. Cells from these cancers and normal cells have different gene expression profiles. Such dysregulation can be exploited with novel drugs that modulate the acetylation of proteins. We present KH16, a novel compound that causes protein hyperacetylation and shifts the balance of protein expression towards cell death. Promisingly, KH16 kills tumor cells but not normal cells. Moreover, KH16 is more effective than clinically well-established and currently tested drugs with a similar mode of action. Future research can focus on KH16 and compounds with a similar chemotype for anti-cancer therapy.Epigenetic modifiers of the histone deacetylase (HDAC) family are often dysregulated in cancer cells. Experiments with small molecule HDAC inhibitors (HDACi) have proven that HDACs are a vulnerability of transformed cells. We evaluated a novel hydroxamic acid-based HDACi (KH16; termed yanostat) in human pancreatic ductal adenocarcinoma (PDAC) cells, short- and long-term cultured colorectal cancer (CRC) cells, and retinal pigment epithelial cells. We show that KH16 induces cell cycle arrest and apoptosis, both time and dose dependently in PDAC and CRC cells. This is associated with altered expression of BCL2 family members controlling intrinsic apoptosis. Recent data illustrate that PDAC cells frequently have an altered expression of the pro-apoptotic BH3-only protein NOXA and that HDACi induce an accumulation of NOXA. Using PDAC cells with a deletion of NOXA by CRISPR-Cas9, we found that a lack of NOXA delayed apoptosis induction by KH16. These results suggest that KH16 is a new chemotype of hydroxamic acid HDACi with superior activity against solid tumor-derived cells. Thus, KH16 is a scaffold for future research on compounds with nanomolar activity against HDACs.

Increased metabolic acid production and upregulation of net acid extrusion render pH homeostasis profoundly dysregulated in many cancers. Plasma membrane activity of vacuolar H+ ATPases (V-ATPases) has been implicated in acid extrusion and invasiveness of some cancers, yet often on the basis of unspecific inhibitors. Serving as a membrane anchor directing V-ATPase localization, the a subunit of the V0 domain of the V-ATPase (ATP6V0a1-4) is particularly interesting in this regard. Here, we map the regulation and roles of ATP6V0a3 in migration, invasion, and growth in pancreatic ductal adenocarcinoma (PDAC) cells. a3 mRNA and protein levels were upregulated in PDAC cell lines compared to non-cancer pancreatic epithelial cells. Under control conditions, a3 localization was mainly endo-/lysosomal, and its knockdown had no detectable effect on pHi regulation after acid loading. V-ATPase inhibition, but not a3 knockdown, increased HIF-1α expression and decreased proliferation and autophagic flux under both starved and non-starved conditions, and spheroid growth of PDAC cells was also unaffected by a3 knockdown. Strikingly, a3 knockdown increased migration and transwell invasion of Panc-1 and BxPC-3 PDAC cells, and increased gelatin degradation in BxPC-3 cells yet decreased it in Panc-1 cells. We conclude that in these PDAC cells, a3 is upregulated and negatively regulates migration and invasion, likely in part via effects on extracellular matrix degradation.

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive and scourging soft tissue tumor worldwide. Its current incidence is 13 per 100,000 US population with a very low 5-years survival rate (5%) and estimated to be the second leading cause of cancer-related death by 2030. Most diagnoses are made at advanced disease states warranting combination chemotherapy. Fluorouracil (5-FU) is an effective drug in treating PDAC; however, rapid degradation and systemic instability remain a drawback to its efficacy. The objective of this study was to chemically modify 5-FU to 1,3 bistetrahydrofuran-2yl-5-FU (MFU) to prolong its systemic stability and enhance the anticancer activity of 5-FU. Method: 5-FU was chemically modified to MFU using tetrahydrofuran-2-yl acetate and 1,8-Diazabicyclo (5.4. 0)undec-7-ene (DBU) in Dimethyl Formamide (DMF). MFU was characterized using nuclear magnetic resonance (NMR) to determine new bond formation, mass spectrometer (MS) for molecular weight determination, high-performance liquid chromatography (HPLC) to determine percent purity, and micro-elemental analysis used to ascertain the presence of elemental composition and purity. Percent conversion of MFU to 5FU was determined using PDAC cells. In vitro anticancer activity of MFU was tested using 2D and 3D MiaPaCa-2 and PANC-1 PDAC cultures and cell viability study performed using the alamar blue assay. Apoptotic and cell cycle studies were performed on MFU treated MiaPaCa-2 and PANC-1 cells using flow cytometry. Results: Molecular weight of synthesized MFU (C12H15FN2O4) was determined to be 270.02 using the Electrospray Ionization (ESI) (MS (M+H)+ = 270.08). While percent purity of MFU was found to be greater than 99.6%, melting point was determined to be 115±2 °C and retention time (RT) was 1.85 minutes. For MFU conversion to 5-FU studies, 4.1% of 25µM and 7.6% of 50µM of MFU incubated MiaPaCa-2 cells was converted to 5-FU over a period of 24 hr showing an incremental production of 5-FU from MFU based on concentration. For in vitro study, half-maximal inhibitory concentration (IC50) of 5-FU treated 2D MiaPaCa-2 culture was 3.4 ±1.1µM while that of MFU treated 2D MiaPaCa-2 culture was 2.1± 0.2 µM. The IC50 value of 5-FU treated 3D MiaPaCa-2 culture was found to be (8.5±1.2µM), while IC50 value for MFU treated 3D MiaPaCa-2 culture was (7.2±1.1µM). Put together, IC50 value for MFU for either 2D or 3D was significantly lower compared with IC50 value 5-FU (P=0.021 (MFU vs 5-FU) for 2D and P=0.04 (MFU vs 5-FU) for 3D). A similar trend was noted when PANC-1 cells were used. Apoptotic and cell cycle studies were similar to that of the 5-FU with most of the cells (54%) in late apoptosis after 48 h of treatment and 64% vs 33% of cells arrested at the G1 and S phase of the cell cycle respectively. Conclusion: The studies demonstrated that MFU may be an alternate approach to improve the delivery, systemic stability, and efficacy of 5-FU in the treatment of PDAC tumors. Citation Format: Nkafu Bechem Ndemazie, Andriana Inkoom, Xue Y. Zhu, Edward Agyare. Optimizing the efficacy of 5-FU as a chemotherapeutic agent in advanced pancreatic ductal adenocarcinoma (PDAC) using MIAPaCa-2 and PANC-1 cells [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-047.

Simple SummaryOncogenic KrasG12D and tumor inflammation are critical components of the development and dissemination of pancreatic ductal adenocarcinoma (PDAC). The aim of this study is to investigate a lesser-known cytokine, CCL15, that functions as a new downstream target of KrasG12D with the purpose of regulating PDAC cell migration and invasion. We showed increased levels of CCL15 as well as the presence of its receptors, including CCR1 and CCR3, in PDAC tissues and cell lines. The knockdown of CCL15 diminished metastatic Panc-1 cell migration, whereas the treatment of CCL15 in non-metastatic BxPC-3 cells promoted BxPC-3 cell motility. Similar results were verified using murine metastatic PDAC KP-2 cells. Furthermore, we demonstrated that CCL15-modulated PDAC cell migration through the upregulation of cellular reactive oxygen species (ROS) levels and the knockdown of KrasG12D resulted in a decrease in CCL15. Altogether, our data unveiled a new mechanism of oncogenic KrasG12D in modulating PDAC inflammation and spreading.Pancreatic ductal adenocarcinoma (PDAC) is well known for its high death rate due to prompt cancer metastasis caused by cancer cell migration and invasion within the early stages of its development. Here, we reveal a new function of cytokine CCL15, namely the upregulation of PDAC cell migration and invasion. We showed increased levels of CCL15 transcripts and protein expressions in human PDAC tissue samples, as well as in cultured cell lines. Furthermore, PDAC cells also expressed CCL15 receptors, including CCR1 and CCR3. Murine PDAC cell lines and tissues strengthened this finding. The manipulation of CCL15 in metastatic Panc-1 cells through CCL15 knockdown or CCL15 neutralization decreased Panc-1 cell motility and invasiveness. In addition, treating non-metastatic BxPC-3 cells with recombinant CCL15 accelerated the cell migration of BxPC-3. A reduction in the levels of reactive oxygen species (ROS) by either N-Acetyl-L-Cysteine treatment or p22phox knockdown led to a decrease in Panc-1 cell migration and a reversed effect on recombinant CCL15-promoted BxPC-3 cell movement. Importantly, the knockdown of oncogenic Kras in Panc-1 cells abolished CCL15 protein expression and impeded cell migration without affecting PDAC cell growth. Altogether, our work elucidates an additional molecular pathway of oncogenic Kras to promote PDAC metastasis through the upregulation of cell migration and invasion by the Kras downstream CCL15, a lesser-known cytokine within the cancer research field.

The H19 long non-coding RNA is highly expressed and carries out various functions in different types of cancers. Recently, we reported that H19 contributes to the metastasis of pancreatic ductal adenocarcinoma (PDAC) cells and its inhibition reduces metastasis in vivo. However, the molecular mechanisms underlying the metastasis-promoting role of H19 in PDAC cells remain unclear. With a focus on cancer stem cells (CSCs), we elucidated the mechanisms by which H19 regulates PDAC metastasis through the overexpression and knockdown of H19 in PDAC cells. To determine whether H19 is expressed heterogeneously or homogeneously in human PDAC cells, we examined its expression in PANC-1 cells using a highly sensitive in situ hybridization technique. Under 2D-culture conditions, PANC-1 cells showed heterogeneous H19 expression and the presence of small populations of H19-expressing cells. In contrast, numerous H19-expressing PANC-1 cells were detected in 3D-cultured spheres. These results suggest that H19 is expressed in CSC-like cells among PANC-1 cells. To investigate the involvement of H19 in the development of CSC characteristics, we examined self-renewal ability, anti-cancer drug resistance, and CSC-marker expression. Sphere formation of PDAC cells depended on H19expression. However, other CSC characteristics of the cells, including CSC-marker expression and anticancer-drug resistance were unaffected by H19 levels. In addition to its role in the development of CSC characteristics, we investigated the involvement of H19 in stromal invasion, which is a key step in the metastatic cascade. Although the invasion ability of PDAC cells was dependent on H19 expression, metalloproteinase activity, a key mediator of invasion, was independent of H19 expression. During the process of invasion, a critical event is the adhesion of cancer cells to the extracellular matrix. Therefore, we investigated whether H19 contributes to this cell-to-matrix adhesion step. We found that H19 promoted cell adhesion by regulating the expression of integrins and CD24. Notably, the increased adhesion of H19-overexpressing cells was blocked by an anti-β1-integrin antibody, which resulted in the inhibition of sphere formation and invasion. Taken together, H19 plays critical roles in CSC self-renewal and cell adhesion of PDAC cells that lead to invasion and metastasis. Our findings suggest that H19 represents a novel therapeutic target for the metastasis of pancreatic cancer. Citation Format: Norihiko Sasaki, Masashi Toyoda, Hisashi Yoshimura, Yoko Matsuda, Tomio Arai, Yoko Itakura, Fujiya Gomi, Junko Aida, Toshiyuki Ishiwata. Metastasis-promoting role of H19 long non-coding RNA in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3568.

Background The hsa_circRNA_103809 (circ_0072088) has been an emerging tumour regulator in human cancers, and is identified as one most aberrantly expressed circRNA in patients with pancreatic ductal adenocarcinoma (PDAC). However, the role of circ_0072088 remains unclear in PDAC cells. Methods Expression of circ_0072088, microRNA (miR)-545-3p and solute carrier family 7 member 11 (SLC7A11) was detected by real-time quantitative PCR and western blotting. Cell progression was measured by cell counting kit (CCK)-8 assay, transwell assays and flow cytometry, as well as xenograft tumour models. Glycolysis was evaluated by commercial assay kits. The interaction among circ_0072088, miR-545-3p and SLC7A11 was confirmed by dual-luciferase reporter assay. Results Circ_0072088 was upregulated in PDAC tumours and cells; besides, high circ_0072088 level was associated with high tumour-node-metastasis (TNM) stage. The circ_0072088 siRNA suppressed cell viability, migration, invasion, extracellular acidification rate (ECAR), lactate production, glucose uptake, and ATP generation, but promoted apoptosis rate and oxygen consumption rate (OCR) in SW1990 and PANC-1 cells. In vivo, circ_0072088 knockdown retarded tumour growth of PANC-1 cells. Overexpressing miR-545-3p mimicked circ_0072088 siRNA-induced actions, and inhibited cell progression and glycolysis of SW1990 and PANC-1 cells. Moreover, SLC7A11 downregulation could be mediated by both circ_0072008 siRNA and miR-545-3p mimic, and participating in suppressive role in cell progression and glycolysis of SW1990 and PANC-1 cells. In mechanism, miR-545-3p was targeted by circ_0072008, and SLC7A11 was target of miR-545-3p. Conclusion Circ_0072088 elicited oncogenic role in malignant cell progression and glycolysis of PDAC cells through circ_0072088/miR-545-3p/SLC7A11 pathway. Highlights Circ_0072088 was upregulated in PDAC tumours and was associated with high tumour burden. Blocking circ_0072088 suppressed cell proliferation, migration, invasion, and glycolysis in PDAC cells. Circ_0072088 could directly regulate miR-545-3p, and SLC7A11 was a target of miR-545-3p. Restoring miR-545-3p mimicked the effects of circ_0072088 knockdown in PDAC cell in vitro.

CEP164-GLI2 association ensures the hedgehog signaling in pancreatic cancer cells

Although increased aerobic glycolysis is common in various cancers, pancreatic ductal adenocarcinoma (PDAC) cells can survive a state of glycolysis suppression. We aimed to identify potential therapeutic targets in glycolysis-suppressed PDAC cells. By screening anticancer metabolic compounds, we identified SP-2509, an inhibitor of lysine-specific histone demethylase 1A (LSD1), which dramatically decreased the growth of PDAC PANC-1 cells and showed an anti-tumoral effect in tumor-bearing mice. The growth of glycolysis-suppressed PANC-1 cells was also inhibited by another LSD1 inhibitor, OG-L002. Similarly, the other two PDAC cells (PK-1 and KLM-1) with suppressed glycolysis exhibited anticancer effects against SP-2509. However, the anticancer effects on PDAC cells were unrelated to LSD1. To investigate how PDAC cells survive in a glycolysis-suppressed condition, we conducted proteomic analyses. These results combined with our previous findings suggested that glucose-starvation causes PDAC cells to enhance mitochondrial oxidative phosphorylation. In particular, mitochondrial fatty acid metabolism was identified as a key factor contributing to the survival of PDAC cells under glycolysis suppression. We further demonstrated that SP-2509 and OG-L002 disturbed fatty acid metabolism and induced lipid droplet accumulation through the impairment of lipophagy, but not bulk autophagy. These findings indicate a significant potential association of lipophagy and anticancer effects in glycolysis-suppressed PDAC cells, offering ideas for new therapeutic strategies for PDAC by dual inhibition of glycolysis and fatty acids metabolism.

Background: Arginine (Arg) deprivation is a promising therapeutic approach for tumors with low argininosuccinate synthetase 1 (ASS1) expression. However, its efficacy as a single agent therapy needs to be improved as resistance is frequently observed. Methods: A tissue microarray was performed to assess ASS1 expression in surgical specimens of pancreatic ductal adenocarcinoma (PDAC) and its correlation with disease prognosis. An RNA-Seq analysis examined the role of ASS1 in regulating global gene transcriptome. A high throughput screen of FDA-approved oncology drugs identified synthetic lethality between histone deacetylase (HDAC) inhibitors and Arg deprivation in PDAC cells with low ASS1 expression. We examined HDAC inhibitor panobinostat (PAN) and Arg deprivation in a panel of human PDAC cell lines, in ASS1-high and -knockdown/knockout isogenic models, in both anchorage-dependent and -independent cultures, and in multicellular complex cultures that model the PDAC tumor microenvironment. We examined the effects of combined Arg deprivation and PAN on DNA damage and the protein levels of key DNA repair enzymes. We also evaluate the efficacy of PAN and ADI-PEG20 (an Arg-degrading agent currently in Phase II clinical trials) in xenograft models with ASS1-low and -high PDAC tumors. Results: Low ASS1 protein level is a negative prognostic indicator in PDAC. Arg deprivation in ASS1-deficient PDAC cells upregulated asparagine synthetase (ASNS) which redirected aspartate (Asp) from being used for de novo nucleotide biosynthesis, thus causing nucleotide insufficiency and impairing cell cycle S-phase progression. Comprehensively validated, HDAC inhibitors and Arg deprivation showed synthetic lethality in ASS1-low PDAC cells. Mechanistically, combined Arg deprivation and HDAC inhibition triggered degradation of a key DNA repair enzyme C-terminal-binding protein interacting protein (CtIP), resulting in DNA damage and apoptosis. In addition, S-phase-retained ASS1-low PDAC cells (due to Arg deprivation) were also sensitized to DNA damage, thus yielding effective cell death. Compared to single agents, the combination of PAN and ADI-PEG20 showed better efficacy in suppressing ASS1-low PDAC tumor growth in mouse xenograft models. Conclusion: The combination of PAN and ADI-PEG20 is a rational translational therapeutic strategy for treating ASS1-low PDAC tumors through synergistic induction of DNA damage. Citation Format: Stephanie S Kim, JING CUI, Shili Xu, Soumya Poddar, Thuc M. Le, Luyi Li, Nanping Wu, Alexandra Moore, Lei Zhou, Alice Yu, Amanda M. Dann, Irmina A. Elliott, Evan R. Abt, Woosuk Kim, David W. Dawson, Caius G. Radu, Timothy R. Donahue. Histone deacetylase inhibition is synthetically lethal with arginine deprivation in pancreatic cancers with low argininosuccinate synthetase 1 expression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 554.

Hypoxia has been shown to induce gemcitabine (GEM) resistance in pancreatic ductal adenocarcinoma (PDAC) cells, however, the underlying mechanisms remain to be clarified. In the present study, we investigated whether activation of Vav1/Rac1/HIF-1α axis is responsible for hypoxia-induced GEM resistance in PDAC cells. Our results showed that Rac1 activation contributed to hypoxia-induced GEM resistance in PANC-1 cells. Hypoxia treatment led to an increased expression level of Vav1, which was responsible for Rac1 activation and GEM resistance in PDAC cells. Furthermore, Rac1 mediated hypoxia-induced GEM resistance by upregulating HIF-1α in PDAC cells. Taken together, these findings suggest that hypoxia induces GEM resistance in PDAC cells by activating the Vav1/Rac1/HIF-1α signaling pathway.

Histone deacetylase inhibitors have been found to have potent anticancer activities, partly induced by tumour cell apoptosis. The clearance of apoptotic tumour cells is an important mechanism of antitumour immune surveillance. The aim of this study was to assess the impact of 4-phenylbutyrate (4-PB) and its immunological effects on the macrophage clearance of apoptotic pancreatic ductal adenocarcinoma (PDAC) cells. To this end, a co-culture system of human macrophages from donors and PDAC patients, and PDAC cell lines (T3M4, PANC-1 and AsPC-1) was established to study the effect of 4-PB. Apoptosis and phagocytic activity were analysed using flow cytometry, and phagocytosis was confirmed by confocal microscopy. Further, p21 expression was quantified by immunoblot analysis. 4-PB treatment (0-10 mM) resulted in a dose-dependent induction of tumour cell apoptosis in two of the cell lines (T3M4 and PANC-1), but it also induced human macrophage apoptosis. The apoptotic effect of gemcitabine on PDAC cells was further enhanced by 4-PB. Moreover, 4-PB led to a dose-dependent overexpression of the cell cycle regulator p21 in tumour cells. In co-culture, apoptotic PDAC cells were phagocytosed by donor macrophages and phagocytosis was increased through tumour cell exposure to 4-PB and/or gemcitabine, whereas phagocytosis of PANC-1 cells was reduced using macrophages of PDAC patients treated with 4-PB. The 4-PB treatment induced human macrophage expression of the pro-angiogenic IL-8 and simultaneously inhibited inflammatory cytokine release through modulation of IL-10 and TNFα after phagocytosis of apoptotic PDAC cells. In conclusion, the 4-PB treatment activated tumour cell death in PDAC cells, resulting in tumour cell phagocytosis by macrophages. The latter were characterized by an anti-inflammatory and pro-angiogenic cytokine response demonstrating adverse, tumour-promoting effects of macrophages on tumour cells. Thus, the potential of 4-PB as an anticancer agent against PDAC cannot be reliably assessed without taking into account the complex tumour microenvironment.

Objective To examine the expression of miR-19b in pancreatic ductal adenocarcinoma (PDAC) cell lines, and invetigate the functional role of miR-19b in proliferation, migration and invasion of PDAC cells. Methods Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to detect the expression level of miR-19b in human pancreatic ductal epithelial cell line (HPDE), human PDAC cell lines (PANC1, MiaPaCa2 and BxPC3) and huamn PDAC metastasis cell line COLO357 and its fast-growing variant FG. PDAC cell lines stably over-expressing of low expressing miR-19b were constructed. Transwell assay and Matrigel assay were carried out to examine the migration and invasion capabities of PDAC cells with miR-19b down-regulated or up-regulated. Methyl thiazol tetrazolium (MTT) and colony formation assay were performed on PDAC cell lines with miR-19b silenced or overexpressed. Results The results of RT-qPCR showed the expression level of miR-19b in human PDAC cell lines PANC1, MiaPaCa2, BxPC3 and metastatic cell line COLO357 and FG (198.45±21.22, 221.37±18.59, 182.51±13.48, 317.64±15.20, 331.34±17.18) was significantly higher than that in HPDE (98.21±14.54), (P=0.003, 0.005, 0.021, 0.001, 0.001) and the difference was statistically significant. Transwell cell migration assay and Matrigel cell invasion assay revealed that the migration and invasion ability of FG cells after miR-19b silencing [(22.54±2.87)%, (28.87±5.62)%] was significantly decreased as compared with the control group [(99.65±3.07)%, (98.73±4.38)%], (P=0.005, 0.002) and the difference was statistically significant. In contrast, the migration and invasion ability of BxPC3 cells overexpressing miR-19b [(317.53±10.21)%, (286.77±12.83)%] was significantly higher than that in the control group [(97.89±5.31)%, (98.25±7.57)%] (P=0.003, 0.007) and the difference was statistically significant. The colony formation and MTT assay showed that after miR-19b silencing, the expression of p21 and p27 in PDAC cells was significantly reduced as compared with the control group (P=0.003, 0.005) and the difference was statistically significant. The results of Western blotting indicated that the silencing of miR-19b resulted in the up-regulation of p21 and p27 in PDAC cells by (3.25±0.27, 5.38±0.33) as compared with the control group (P=0.003, 0.001) and the difference was statistically significant. The overexpression of miR-19b led to the down-regulation of p21 and p27 by (2.68±0.15, 3.27±0.27) as compared with the control group (P=0.006, 0.005) and the difference was statistically significant. Conclusion MiR-19b could promote the migration and invasion of PDAC cells and increase the proliferation capability. Key words: MicroRNA-19b; Pancreatic ductal adenocarcinoma; Metastsis; Proliferation