Cell Lines BxPC-3 Research Articles

The effects of miRNAs-107 on cell proliferation, senescence and invasion of pancreatic cancer PANC-1 cells

Objective To investigate the effects of miRNAs-107(miR-107) on pancreatic cancer proliferation, senescence and invasion. Methods MiR-107 expression levels in 3 pancreatic cancer cell lines PANC-1, ASPC-1, BXPC-3 and normal pancreatic HTERT-HPNE cells were studied by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). PANC-1 cells were transfected with 50 nmol/L anti-miR-107 or negative control using Lipofectamine 2000. After transfection, the miR-107 expression was measured by qRT-PCR. Cell proliferation was tested by methylthiazol tetrazolium (MTT) assay. Cell senescence was detected by β-galactosidase staining. The expression levels of PCNA, P16INK4A and MMP2 were measured by qRT-PCR. Results Compared with the HTERT-HPNE cells, the expression level of miR-107 in 3 pancreatic cancer cell lines was significantly increased (P<0.01). After transfected with 50 nmol/L anti-miR-107, cell proliferation was inhibited, and cell senescence were increased in PANC-1 cells (P<0.05), and there was no obvious change in cell invasion. Compared with the HTERT-HPNE cells, after transfected with anti-miR-107, the PCNA expression was significantly decreased and P16INK4A was significantly increased, but expression of MMP2 didn’t change significantly. Conclusions These results demonstrate that miR-107 promotes the proliferation and escapes cell senescence in PANC-1 cells by targeting PCNA and P16INK4A. But it has no obvious effects on cell invasion. Therefore, it may be a new target for the biologic therapy for pancreatic cancer. Key words: Pancreatic cancer; MiRNAs-107(MiR-107); Proliferation; Senescence; Invasion

Lignans and diterpenes isolated from Tirpitzia ovoidea and their biological activities

A new lignan, tirpitzin A (17) together with 20 known compounds (1–16, and 18–21) were isolated from the ethyl acetate soluble fraction of ethanol extract of the aerial parts of Tirpitzia ovoidea. The structure of new compound was elucidated by means of spectroscopic analysis. Of the known compounds, 7–21 were isolated from Linaceae family for the first time. The pharmacological activity of the crude extracts was tested using a mouse inflammation model induced by dimethyl benzene. The results demonstrated that the ethyl acetate soluble fraction had anti-inflammatory activity. Moreover, the cytotoxic and anti-inflammatory activities of some compounds were studied. The new compound 17 showed moderate cytotoxic effect against BxPC-3 cell line (IC50 = 19.51μmol·L−1) and Compound 10 showed significant cytotoxicity against HepG2, HL-60, U87 and BxPC-3 cell lines with IC50 values in the range 4.2-8.3μmol·L−1. Additionally, Compounds 2, 10, 11, and 13 exhibited potent inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages at the concentration of 50μmol·L−1.

Targeted Delivery of Auristatin-Modified Toxins to Pancreatic Cancer Using Aptamers.

Pancreatic cancer is one of the most lethal malignancies. Treatment with the first-line agent, gemcitabine, is often unsuccessful because it, like other traditional chemotherapeutic agents, is non-specific, resulting in off-target effects that necessitate administration of subcurative doses. Alternatively, monomethyl auristatin E (MMAE) and monomethyl auristatin F (MMAF) are highly toxic small molecules that require ligand-targeted delivery. MMAE has already received FDA approval as a component of an anti-CD30 antibody-drug conjugate, brentuximab vedotin. However, in contrast to antibodies, aptamers have distinct advantages. They are chemicals, which allows them to be produced synthetically and facilitates the rapid development of diagnostics and therapeutics with clinical applicability. In addition, their small size allows for enhanced tissue distribution and rapid systemic clearance. Here, we assayed the toxicity of MMAE and MMAF conjugated to an anti-transferrin receptor aptamer, Waz, and an anti-epidermal growth factor receptor aptamer, E07, on the pancreatic cancer cell lines Panc-1, MIA PaCa-2, and BxPC3. In vitro, our results indicate that these aptamers are a viable option for the targeted delivery of toxic payloads to pancreatic cancer cells.

Phytotherapeutics Oridonin and Ponicidin show Additive Effects Combined with Irradiation in Pancreatic Cancer in Vitro.

BackgroundChemoradiation of locally advanced non-metastatic pancreatic cancer can lead to secondary operability by tumor mass reduction. Here, we analyzed radiomodulating effects of oridonin and ponicidin in pancreatic cancer in vitro. Both agents are ent-kaurane diterpenoids, extracted from Isodon rubescens, a plant that is well known in Traditional Chinese Medicine. Cytotoxic effects have recently been shown in different tumor entities for both agents.Materials and methodsPancreatic cancer cell lines AsPC-1, BxPC-3, Panc-1 and MIA PaCa-2 were pretreated with oridonin or ponicidin and irradiated with 2 Gy to 6 Gy. Long-term survival was determined by clonogenic assay. Cell cycle effects and intensity of γH2AX as indicator for DNA double-strand breaks were investigated by flow cytometry. Western blotting was used to study the DNA double-strand break repair proteins Ku70, Ku80 and XRCC4.ResultsOridonin and ponicidin lead to a dose-dependent reduction of clonogenic survival and an increase in γH2AX. Combined with irradiation we observed additive effects and a prolonged G2/M-arrest. No relevant changes in the levels of the DNA double-strand break repair proteins were detected.ConclusionsPretreatment with oridonin or ponicidin followed by irradiation lead to an additional reduction in survival of pancreatic cancer cells in vitro, presumably explained by an induced prolonged G2/M-arrest. Both agents seem to induce DNA double-strand breaks but do not interact with the non-homologous end joining (NHEJ) pathway.

PHGDH is an independent prognosis marker and contributes cell proliferation, migration and invasion in human pancreatic cancer

PurposeTo investigate the expression, clinical significance, biological function, and the potential mechanism of PHGDH in pancreatic cancer. MethodsThe expression of PHGDH in human pancreatic cancer tissues and corresponding adjacent normal tissues were analyzed through immunohistochemistry staining. Simultaneously, the association between the PHGDH expression and the clinicopathological parameters and OS and DFS was evaluated. Human pancreatic cancer cell line BxPC-3 and SW1990 were selected to investigate the effect of PHGDH knockdown on cell proliferation, migration, and invasion. In addition, we performed western blot to assess the expression of cyclin B1, and cyclin D1, MMP-2, and MMP-9 protein. ResultsOur results suggested that the expression of PHGDH is increased in pancreatic cancer compared with adjacent normal tissues and the increased expression of PHGDH is associated with tumor size, lymph node metastasis, and TNM state of pancreatic cancer patients. Moreover, the expression of PHGDH is an independent prognostic indicator for pancreatic cancer patients. In addition, we found that knockdown of PHGDH in pancreatic cancer cells inhibits the cell proliferation, migration, and invasion abilities by down-regulating the expression of cyclin B1, and cyclin D1, MMP-2, and MMP-9. ConclusionsOur data indicated that the expression of PHGDH is increased in pancreatic cancer and is an independent molecular prognostic factor for pancreatic cancer patients. In addition, PHGDH controls cell proliferation, migration and invasion abilities. Therefore, PHGDH could serve as an important prognostic indicator and therapeutic target for pancreatic cancer.

New Adducts of Iriflophene and Flavonoids Isolated from Sedum aizoon L. with Potential Antitumor Activity.

Four new special compounds with character of an iriflophene unit and a flavonoid unit connecting via a furan ring were isolated from the roots of Sedum aizoon L. Their corresponding structures were elucidated on the basis of spectroscopic analysis. The in vitro anti-proliferative activities against BXPC-3, A549, and MCF-7 tumor cell lines were evaluated. Compounds 3 and 4 exhibited moderate cytotoxic activities with IC50 ranging from 24.84 to 37.22 μmol L−1, which was capable for further drug exploration.

The clinnical significance of TRPM8 ion channels over-expressed in pancreatic cancer

Objective TRPM8 as a clinical biomarker and potential drug target may provide a gui-dance in accurately judging the malignant potential and prognosis of pancreatic cancer. Downregulating the expression of TRPM8 leads to inhibition of the proliferation of pancreatic cancer cells and this may provide a new target for personalized pancreatic cancer treatment. Methods The pancreatic cancer tissues of 77 patients and the normal pancreas tissues of 30 persons were collected and examined by immunohistochemistry. PCR, gene knockout, Western Blot, CCK8 and patch clamp experiments were performed on pancreatic cancer cell lines BxPC-3, PANC1 and normal pancreatic cell line HPCY-5. Results Immunohistochemistry and Western Blot experiments showed that the TRPM8 channel protein was highly expressed in cancer cells, and the high expression of channel proteins was related to the degree of tumor differentiation (P<0.05). The detection of the TRPM8 mRNA in pancreatic cancer cell lines BxPC-3 and PANC1 by QPCR showed absolutely high expressions relative to the normal cell line HPCY-5. The results of patch clamp and CCK8 showed that the membrane currents and proliferation of tumor cells were significantly decreased after TRPM8 gene knockout, and the difference is significant (P<0.05). Conclusions The TRPM8 ion channel was higher in pancreatic cancer cells than that in normal pancreatic cells. Overexpression of TRPM8 was closely related to tumor cell proliferation and invasion ability. Key words: Pancreatic cancer; TRPM8; Western Blot; Patch clamp

Ginsenoside Rg3 enhances the anti-proliferative activity of erlotinib in pancreatic cancer cell lines by downregulation of EGFR/PI3K/Akt signaling pathway

Erlotinib has shown activity in the management of pancreatic cancer. However, the benefit of EGFR blockade is limited due to EGFR independent PI3K/Akt signaling pathway. Studies have reported that Ginsenoside Rg3 strongly inhibited PI3K-Akt signaling pathway of many carcinomas. We aimed to investigate the activity of Ginsenoside Rg3 to sensitize erlotinib in treating pancreatic cancer in vitro and in vivo. Human pancreatic cancer cell lines BxPC-3 and AsPC-1 were used. Cell proliferation and colony formation assay, Annexin V/PI apoptosis analysis, Western blot analysis, immunohistochemistry and in vivo study were carried out. Ginsenoside Rg3 enhanced the anti-proliferative effects of erlotinib in BxPC-3 and AsPC-1 pancreatic cancer cells and xenograft. Ginsenoside Rg3 enhanced erlotinib-induced apoptosis and increased caspase-3,9 and PARP cleavage expression levels. Erlotinib/Ginsenoside Rg3 treatment decreased the levels of p-EGFR, p-PI3K, and p-Akt expression significantly. Ginsenoside Rg3 could enhance the efficacy of erlotinib to inhibit the proliferation of pancreatic cancer cells via induction of apoptosis and downregulation of the EGFR/PI3K/AKT pathway.

Interleukin 35 Expression Correlates With Microvessel Density in Pancreatic Ductal Adenocarcinoma, Recruits Monocytes, and Promotes Growth and Angiogenesis of Xenograft Tumors in Mice

Cells of the monocyte lineage contribute to tumor angiogenesis. Interleukin 35 (IL35) is a member of the IL12 family produced by regulatory, but not effector, T cells. IL35 is a dimer comprising the IL12 alpha and IL27 beta chains, encoded by IL12A and EBI3, respectively. Expression of IL35 is increased in pancreatic ductal adenocarcinomas (PDACs) compared with normal pancreatic tissues, and promotes metastasis. We investigated the role of IL35 in monocyte-induced angiogenesis of PDAC in mice. We measured levels of IL35 protein, microvessel density, and numbers of monocytes in 123 sequential PDAC tissues from patients who underwent surgery in China in 2010. We performed studies with the human PDAC cell lines CFPAC-1, BxPC-3, Panc-1, MIA-PaCa-2, and mouse PDAC cell line Pan02. Monocyte subsets were isolated by flow cytometry from human peripheral blood mononuclear cells. Fused human or mouse IL12A and EBI3 genes were overexpressed in PDAC cells or knocked down using small hairpin RNAs. Cells were grown as xenograft tumors in SCID mice; some mice were given injections of an IL35-neutralizing antibody and tumor growth was monitored. We performed chemotaxis assays to measure the ability of IL35 to recruit monocytes. We analyzed mRNA sequences of 179 PDACs in the Cancer Genome Atlas to identify correlations between expression of IL12A and EBI3 and monocyte markers. Monocytes incubated with IL35 or PDAC cell supernatants were analyzed in tube formation and endothelial migration assays. In PDAC samples from patients, levels of IL35 mRNA and protein correlated with microvessel density and infiltration of monocyte lineage cells. In cells and mice with xenograft tumors, IL35 increased recruitment of monocytes into PDAC tumors, which required CCL5. Upon exposure to IL35, monocytes increased expression of genes whose products promote angiogenesis (CXCL1 and CXCL8). IL35 activated transcription of CCL5, CXCL1, and CXCL8 by inducing GP130 signaling, via IL12RB2 and phosphorylation of STAT1 and STAT4. A combination of a neutralizing antibody against IL35 and gemcitabine significantly decreased monocyte infiltration, microvessel density, and volume of xenograft tumors grown from PDAC cells in mice. PDAC cells produce IL35 to recruit monocytes via CCL5 and induce macrophage to promote angiogenesis via expression of CXCL1 and CXCL8. IL35 signaling promotes angiogenesis and growth of xenograft tumors from PDAC cells in mice. IL35 might serve as a therapeutic target for patients with pancreatic cancer.

Chemical constituents from petroleum ether fraction of Swertia chirayita and their activities in vitro

The present work is to study the chemical constituents from petroleum ether fraction of Tibetan medicine Swertia chirayita by column chromatography and recrystallization. The structures were identified by physical and chemical properties and spectral data as swerchirin (1), decussatin (2), 1,8-dihydroxy-3,5,7-trimethoxyxanthone (3), 1-hydroxy-3,5,7,8-tetramethoxyxanthone (4), bellidifolin (5), 1-hydroxy-3, 7-dimethoxyxanthone (6), methylswertianin (7), 1-hydroxy-3,5-dimethoxyxanthone (8), erythrodiol (9), oleanolic acid (10), gnetiolactone (11), scopoletin (12), sinapaldehyde (13), syringaldehyde (14), and β-sitosterol (15). Compounds 3, 4, 9, 11-14 were isolated from S. chirayita for the first time. Compounds 9 and 12 were firstly isolated from the genus Swertia. The cytotoxic activities of compounds 1, 2, 5, 7 and 8 against human pancreatic cancer cell lines SW1990 and BxPC-3,and the protective effects of these compounds against hydrogen peroxide (H2O2)-induced oxidative stress in human endothelium-derived EA.hy926 were investigated in vitro. The results showed no obvious effect at the high concentration of 50 μmol•L⁻¹.

Novel histone deacetylase inhibitor AR-42 exhibits antitumor activity in pancreatic cancer cells by affecting multiple biochemical pathways.

ObjectivePancreatic cancer is one of the most lethal types of cancer with a 5-year survival rate of ~5%. Histone deacetylases (HDACs) participate in many cellular processes, including carcinogenesis, and pharmacological inhibition of HDACs has emerged as a potential therapeutic strategy. In this study, we explored antitumor activity of the novel HDAC inhibitor AR-42 in pancreatic cancer.MethodsHuman pancreatic cancer cell lines BxPC-3 and PANC-1 were used in this study. Real-time PCR, RT-PCR, and western blotting were employed to investigate expression of specific genes and proteins, respectively. Translocation of apoptosis-inducing factor was investigated by immunofluorescence and subcellular fractionation. The number of apoptotic cells, cell cycle stages, and reactive oxygen species (ROS) generation levels were determined by flow cytometry. Cell invasiveness was examined by the Matrigel invasion assay. Efficacy of AR-42 in vivo was evaluated by utilizing BxPC-3 xenograft mouse model.ResultsAR-42 inhibited pancreatic cancer cell proliferation by causing G2/M cell cycle arrest via regulating expression levels of genes and proteins involved in cell cycle. AR-42 also induced ROS generation and DNA damage, triggering apoptosis of pancreatic cancer cells via both caspase-3-dependent and caspase-3-independent pathways. In addition, AR-42 increased expression levels of negative regulators of p53 (miR-125b, miR-30d, and miR33), which could contribute to lower expression level of mutant p53 in pancreatic cancer cells. Cell invasion assay showed that AR-42 reduced cancer cell aggressiveness and significantly diminished BxPC-3 xenograft tumor growth in vivo.ConclusionAR-42, a novel HDAC inhibitor, inhibited pancreatic cancer cells by regulating p53 expression, inducing cell cycle arrest, particularly at the G2/M stage, and activating multiple apoptosis pathways. Additionally, AR-42 inhibited cell invasiveness and potently suppressed pancreatic cancer tumors in vivo. We conclude that by virtue of its multiple mechanisms of action, AR-42 possesses a considerable potential as an antitumor agent in pancreatic cancer.

Preparation, characterization and in vitro evaluation of ε-polylysine-loaded polymer blend microparticles for potential pancreatic cancer therapy

Peptide active ingredients show great promise regarding the treatment of various health-endangering diseases. It is reported that L-lysine inhibits the proliferation of several tumour lines in vitro and in vivo. However, proteins and peptide drugs possess certain disadvantages such as in vivo instability and short biological half-life. On the grounds that drug delivery systems can overcome a wide spectrum of bioactive compounds issues, a biopolymeric blend-based microparticulated system capable of delivering ε-polylysine (PLL) was developed. PLL-loaded poly((L)Lactic acid)/poly(D,L-Lactide)-co-poly(ethylene glycol)-based microparticles (PLL-PB-MPs) were prepared and fully characterised exhibiting a narrow size distribution (1.2 ± 0.12 µm), high loading efficiency (81%) and improved thermal stability (Td from 250 °C to 291 °C). The cytotoxicity and antiproliferative effect of PLL-PB-MPs in pancreatic adenocarcinoma cell lines BxPC3 and MIA PaCa-2 were confirmed. Due to their physicochemical and biopharmaceutical properties, PB-MPs constitute a promising carrier to deliver bioactive peptides.

A missing link between RON expression and oncological outcomes in resected left-sided pancreatic cancer.

Alteration and activation of recepteur d'origine nantais (RON) expression is known to be associated with cancer progression and decreased survival in various types of human cancer, including pancreatic cancer. Therefore, in the present study, RON expression levels were determined in resected left-sided pancreatic cancer to evaluate the potential oncological role of RON in the clinical setting of distal pancreatic cancer. From January 2005 to December 2011, a total of 57 patients underwent radical distal pancreatectomy for left-sided pancreatic cancer. Ductal adenocarcinoma was confirmed in all patients. Among these patients, 17 patients who received preoperative neoadjuvant treatment and 7 patients without available paraffin-embedded tissue blocks were excluded from the present study. RON expression in a the pancreatic cancer cell lines ASPC-1, BxPC-3, MiaPaCa-3 and Panc-1, as well as in resected left-sided pancreatic cancer specimens was determined by Western blot analysis. RON and vascular endothelial growth factor (VEGF) overexpression in resected left-sided pancreatic cancer was also evaluated by immunohistochemistry using pre-diluted anti-RON and anti-VEGF antibodies. An association was identified between the oncological outcome and RON overexpression. Increased levels of RON expression were observed in two pancreatic cancer cell lines, AsPC-1 and BxPC-3. RON overexpression was detected in specimens from 15/33 patients (45.5%) using immunohistochemistry. No significant association was identified between RON overexpression and VEGF overexpression (25.5 vs. 87.9%; P=0.667). No significant differences in disease-free survival or disease-specific survival associated with RON overexpression were identified. Although the results of previous studies have suggested that RON is a potential target for the treatment of pancreatic cancer, in the present study no association between RON overexpression and any adverse oncological effect was identified.

Imaging the Role of Multinucleate Pancreatic Cancer Cells and Cancer-Associated Fibroblasts in Peritoneal Metastasis in Mouse Models.

The interaction between pancreatic-cancer cells and stromal cells in the tumor microenvironment (TME) is of particular importance in cancer progression and metastasis. The present report demonstrates the role of cancer-associated fibroblasts (CAFs) and multinucleate pancreatic-cancer cells in peritoneal metastasis. An orthotopic mouse model of pancreatic cancer was established with the human pancreatic cancer cell line BxPC3, which stably expresses green fluorescent protein (GFP). BxPC3-GFP cells formed peritoneal metastases by week 18 after orthotopic implantation. Using an Olympus FV1000 confocal microscope, multi-nucleated cancer cells were frequently observed in the peritoneal metastases. The primary pancreatic tumor and peritoneal-metastases were harvested, cultured and then transplanted subcutaneously. Subcutaneous tumors established from peritoneal-metastatic cells were larger than subcutaneous tumors established from primary-tumor cells. Subcutaneous tumors of each type were subsequently cultured in vitro. CAFs were observed growing out from the tumors established from peritoneal-metastatic cells, but not the tumors established from the primary cancer. The results of the present study suggest that multi-nucleated cancer cells and CAFs were related to peritoneal metastasis of pancreatic cancer.

Abstract 2698: IL-17A alone or in combination with IL-4/IFN-γ induces Duox2/DuoxA2 expression and reactive oxygen production in human colon and pancreatic cancer cells

Abstract NADPH oxidase (NOX)-derived reactive oxygen species (ROS) contribute significantly to inflammation-associated carcinogenesis. Expression of dual oxidase 2 (Duox2), one of seven members of the NOX gene family, is up-regulated in inflammatory bowel disease, chronic pancreatitis, and in many human malignancies including carcinomas of the colon, pancreas, prostate, lung, and breast. Previously, we demonstrated that Stat1 and/or NF-kB play a critical role in modulating the enhanced expression of Duox2, and its cognate maturation factor DuoxA2, by the pro-inflammatory mediators IFN-γ and lipopolysaccharide in human pancreatic cancer cells. This cytokine-mediated increase in Duox2 expression was responsible for a significant increase in tumor cell H2O2 production, DNA damage, and HIF-1α and VEGFA upregulation in pancreatic cancer cell lines. Using the T84 human colon cancer line, and BxPC-3, AsPC-1, and HTB134 pancreatic cancer cell lines, we now report that the pro-inflammatory cytokine IL-17A, pivotal in the adaptive immune response against various pathogens, and in the promotion of colon and pancreatic cancer progression, strongly induces Duox2/DuoxA2 mRNA and protein expression (alone or in combination with IL-4 or IFN-γ). In BxPC-3 cells, IL-17A enhances the expression of Duox2/DuoxA2 in a time- and concentration-dependent manner, which leads to a significant increase in the generation of extracellular H2O2. When IL-17A is combined with IL-4 in either T-84 or AsPc-1 lines, Duox2-mediated ROS formation is sufficient to produce a DNA damage response, indicated by the strong induction of γH2AX expression; moreover, in AsPc-1 cells, Duox2-specific siRNA significantly attenuated cytokine-induced ROS production and γH2AX phosphorylation. IL-17A in combination with IL-4 also significantly increases Stat3 phosphorylation and promotes proliferation in AsPC-1 cells. Ongoing cellular experiments are focused on whether the cytokine-mediated upregulation of Duox2/DuoxA2 is responsible for Stat3 activation and cell growth promotion in the K-ras mutated AsPC-1 cells. Bio-informatic analysis with the TCGA data set, as well as RT-PCR using surgically-resected human colon cancer samples compared to adjacent, uninvolved colonic epithelium revealed that Duox2 was significantly upregulated in human colon cancers. These studies, in concert with our previous data demonstrating high-level Duox protein expression in pancreatitis, pancreatic intra-epithelial neoplasia (PanIN), and frank pancreatic cancer, strongly suggest that ROS, produced as a consequence of cytokine-related Duox2 up-regulation, may be associated with the development of inflammation-related gastrointestinal malignancies. Citation Format: James H. Doroshow, Yongzhong Wu, Jiamo Lu, Smitha Antony, Jennifer Meitzler, Agnes Juhasz, Guojian Jiang, Iris Dahan, Mariam Konate, Krishnendu Roy. IL-17A alone or in combination with IL-4/IFN-γ induces Duox2/DuoxA2 expression and reactive oxygen production in human colon and pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2698. doi:10.1158/1538-7445.AM2017-2698

Abstract 1075: JQ1 induces DNA damage, inhibits expression of DNA repair proteins, and synergizes with PARP inhibitors in pancreatic cancer cells

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer. PDAC is a highly aggressive tumor with a 5-year survival of &amp;lt;6%. Surgery remains the only curative treatment for PDAC patients, but only 20% of newly diagnosed patients have resectable disease. The remaining 80% present with locally advanced or metastatic disease, and receive systemic chemotherapy with gemcitabine. The median survival of this patient population is ~6 months. Development of more effective therapy for this chemorefractory disease is imperative. The goal of the current study was to develop effective combination therapy for PDAC by identifying agents that might be combined with the BET bromodomain inhibitor JQ1, which we have shown to inhibit the growth in vivo of PDAC patient derived xenografts (PDX). Expression profile analysis of tumors from vehicle control and JQ1 treated mice revealed that JQ1 inhibited the expression of multiple gene products involved in DNA repair. Notably, JQ1 inhibited expression of DNA double-strand break (DSB) repair proteins BRCA2 and Ku80. Immunohistochemical staining confirmed down-regulation of expression of both proteins in tumors of mice treated with JQ1. Further, immunoblot and immunofluorescence analyses demonstrated that decreased expression of BRCA2 and Ku80 was coincident with increased levels of DNA damage, as reflected by expression of the DNA DSB marker gamma-H2AX. Data generated in vivo in three independent PDX models corroborated in vitro data generated using pancreatic cancer cell lines BxPC3 and Panc1. The data suggest that JQ1 induces DNA damage by inhibiting DNA repair. Because DNA repair deficiency sensitizes cells to PARP inhibitors, we hypothesized that JQ1-induced DNA repair deficiency would sensitize PDAC cells to PARP inhibitors. To address this hypothesis, we exposed Panc1 and BxPC3 to JQ1 or to a PARP 1/2 inhibitor (veliparib or olaparib) or to the combinations, and assessed the efficacy of each. Growth inhibition data, analyzed using Compusyn software and reported as combination indices, demonstrated that the combinations of JQ1 + veliparib or olaparib exert synergistic cytotoxicity. Further, the combination of JQ1 + a PARP inhibitor increased the accumulation of DNA damage in vitro, compared to either agent alone. We conclude that JQ1 induces DNA damage due at least in part to DNA repair deficiency, and propose that this mechanism sensitizes PDAC cells to PARP inhibitors. Citation Format: Aubrey Lynn Miller, Tracy Gamblin, Leona Council, Robert van Waardenburg, Eddy Yang, James Bradner, Karina Yoon. JQ1 induces DNA damage, inhibits expression of DNA repair proteins, and synergizes with PARP inhibitors in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1075. doi:10.1158/1538-7445.AM2017-1075

Novel Kiteplatin Pyrophosphate Derivatives with Improved Efficacy.

Two new Pt(II) derivatives of kiteplatin ([PtCl2(cis-1,4-DACH)]) with pyrophosphate as carrier ligand, one mononuclear (1) and one dinuclear (2), were synthesized with the aim of potentiating the efficacy of kiteplatin. Complex 1 resulted to be remarkably stable at physiological pH, but it undergoes a fast hydrolysis reaction at acidic pH releasing free pyrophosphate and (aquated) kiteplatin. The dinuclear compound 2 resulted to be less stable than 1 at both neutral and acidic pH forming 1 and (aquated) kiteplatin as first step. Both compounds (1 and 2) do not react as such with 5'-GMP, whereas their hydrolysis products readily form adducts with the nucleotide. The in vitro cytotoxicity assays against a panel of six human cancer cell lines showed that complex 2 affects cancer cell viability even at nanomolar concentrations. The cytotoxic activity of 2 is greater (up to 2 orders of magnitude) than that of cisplatin, oxaliplatin, and kiteplatin, whereas the mononuclear complex 1 has shown a cytotoxic activity comparable to that of oxaliplatin and kiteplatin, but higher than cisplatin. The latter result is not surprising, since the presence of two negative charges reduces the uptake of 1 into the tumor cells as compared to the neutral compound 2. The remarkable activity of 2 against the pancreatic cell line BxPC3 (average IC50 = 0.07 μM) deserves further investigation.

BRM/SMARCA2 promotes the proliferation and chemoresistance of pancreatic cancer cells by targeting JAK2/STAT3 signaling

BackgroundBRM is one of two evolutionarily conserved catalytic ATPase subunits of SWI/SNF complexes and plays important role in cell proliferation, linage specification and development, cell adhesion, cytokine responses and DNA repair. BRM is often inactivated in various types of cancer indicating its indispensable roles in oncogenesis but the mechanisms remain poorly understood. MethodsBRM expression in clinical pancreatic cancer samples was examined by immunohistochemistry and the correlation with patient survival was analyzed. shRNAs targeting BRM were used to establish stable BRM knockdown BxPC-3 and T3M4 cell lines. Cell viability was assessed by CCK-8 assay. Cell proliferation was measured by EdU incorporation assay, colony formation assay and Ki67 staining. Cell cycle and apoptosis were examined by flow cytometry. Growth and chemosensitivity of xenografts initiating from BRM-deficient cells were evaluated, and in situ apoptosis was detected by TUNEL assay. The status of JAK-STAT3 signaling was examined by real-time PCR and Western blot analysis. ResultsHigh BRM expression was correlated with worse survival of pancreatic cancer patients. BRM shRNA reduced the proliferation and increased the sensitivity of pancreatic cancer cells to gemcitabine in vivo and in vitro, and these effects are associated with the inhibition of STAT3 phosphorylation and reduced transcription of STAT3 target genes. ConclusionWe reveal a novel mechanism by which BRM could activate JAK2/STAT3 pathway to promote pancreatic cancer growth and chemoresistance. These findings may offer potential therapeutic targets for pancreatic cancer patients with excessive BRM expression.

Penfluridol induces endoplasmic reticulum stress leading to autophagy in pancreatic cancer.

Pancreatic cancer is one of the most aggressive and difficult to treat cancers. Experimental and clinical evidence suggests that high basal state autophagy in pancreatic tumors could induce resistance to chemotherapy. Recently, we have demonstrated that penfluridol suppresses pancreatic tumor growth by autophagy-mediated apoptosis both in vitro and in vivo; however, the mechanism of autophagy induction by penfluridol was not clear. Several studies have established that endoplasmic reticulum stress could lead to autophagy and inhibit tumor progression. In this study, we demonstrated that penfluridol induced endoplasmic reticulum stress in BxPC-3, AsPC-1, and Panc-1 pancreatic cancer cell lines as indicated by upregulation of endoplasmic reticulum stress markers such as binding protein (BIP), C/EBP homologous protein (CHOP) and inositol requiring 1α (IRE1α) after treatment with penfluridol in a concentration-dependent manner. Inhibiting endoplasmic reticulum stress by pretreatment with pharmacological inhibitors such as sodium phenylbutyrate and mithramycin or by silencing CHOP using CHOP small interfering RNA, blocked penfluridol-induced autophagy. These results clearly indicate that penfluridol-induced endoplasmic reticulum stress lead to autophagy in our model. Western blot analysis of subcutaneously implanted AsPC-1 and BxPC-3 tumors as well as orthotopically implanted Panc-1 tumors demonstrated upregulation of BIP, CHOP, and IRE1α expression in the tumor lysates from penfluridol-treated mice as compared to tumors from control mice. Altogether, our study establishes that penfluridol-induced endoplasmic reticulum stress leads to autophagy resulting in reduced pancreatic tumor growth. Our study opens a new therapeutic target for advanced chemotherapies against pancreatic cancer.

LPS promotes resistance to TRAIL-induced apoptosis in pancreatic cancer

BackgroundThough TRAIL has been hailed as a promising drug for tumour treatment, it has been observed that many tumour cells have developed escape mechanisms against TRAIL-induced apoptosis. As a receptor of LPS, TLR 4, which is expressed on a variety of cancer cells, can be associated with TRAIL-resistance of tumour cells and tumour progression as well as with the generation of an anti-tumour immune response.MethodsIn this study, the sensitivity to TRAIL-induced apoptosis as well as the influence of LPS-co-stimulation on the cell viability of the pancreatic cancer cell lines PANC-1, BxPC-3 and COLO 357 was examined by FACS analyses and a cell viability assay. Subsequently, the expression of TRAIL-receptors was detected via FACS analyses. Levels of osteoprotegerin (OPG) were also determined using an enzyme-linked immunosorbent assay.ResultsPANC-1 cells were shown to be resistant to TRAIL-induced apoptosis. This was accompanied by significantly increased osteoprotegerin levels and a significantly decreased expression of DR4.In contrast, TRAIL significantly induced apoptosis in COLO 357 cells and to a lesser degree in BxPC-3 cells. Co-stimulation of COLO 357 as well as BxPC-3 cells combining TRAIL and LPS resulted in a significant decrease in TRAIL-induced apoptosis. In COLO 357 cells TRAIL-stimulation decreased the levels of OPG thereby not altering the expression of the TRAIL-receptors 1–4 resulting in a high susceptibility to TRAIL-induced apoptosis. Co-stimulation with LPS and TRAIL completely reversed the effect of TRAIL on OPG levels reaching a 2-fold increase beyond the level of non-stimulated cells resulting in a lower susceptibility to apoptosis.In BxPC-3, TRAIL stimulation decreased the expression of DR4 and significantly increased the decoy receptors TRAIL-R3 and TRAIL-R4 leading to a decrease in TRAIL-induced apoptosis. OPG levels remained unchanged. Co-stimulation with TRAIL and LPS further enhanced the changes in TRAIL-receptor-expression promoting apoptosis resistance.ConclusionsHere it has been shown that TRAIL-resistance in pancreatic cancer cells can be mediated by the inflammatory molecule LPS as well as by different expression patterns of functional and non-functional TRAIL-receptors.