Treatment of advanced pancreatic cancer

Elevated expression of nuclear receptor-binding SET domain 3 promotes pancreatic cancer cell growth

The nuclear receptor-binding SET domain 3 (NSD3) catalyzes methylation of histone H3 at lysine 36 (H3K36), and promotes malignant transformation and progression of human cancer. Its expression, potential functions and underlying mechanisms in pancreatic cancer are studied. Bioinformatics studies and results from local human tissues show that NSD3 is upregulated in human pancreatic cancer tissues, which is correlated with poor overall survival. In primary and established pancreatic cancer cells, NSD3 silencing (by shRNAs) or CRISPR/Cas9-induced NSD3 knockout potently inhibited cell proliferation, migration and invasion, while provoking cell cycle arrest and apoptosis. Conversely, ectopic expression of NSD3-T1232A mutation significantly accelerated proliferation, migration, and invasion of pancreatic cancer cells. H3K36 dimethylation, expression of NSD3-dependent genes (Prkaa2, Myc, Irgm1, Adam12, and Notch3), and mTOR activation (S6K1 phosphorylation) were largely inhibited by NSD3 silencing or knockout. In vivo, intratumoral injection of adeno-associated virus (AAV)-packed NSD3 shRNA potently inhibited pancreatic cancer xenograft growth in nude mice. These results suggest that elevated NSD3 could be an important driver for the malignant progression of pancreatic cancer.

The enhancement of Tetrandrine to gemcitabine-resistant PANC-1 cytochemical sensitivity involves the promotion of PI3K/Akt/mTOR-mediated apoptosis and AMPK-regulated autophagy

BACKGROUND

In the process of tumor development, the resistance of pancreatic cancer cells to gemcitabine (GEM) is mainly due to the suppression and dysregulation of apoptosis signals to a large extent. Therefore, it is very necessary to develop pro-apoptotic drugs for combined treatment of pancreatic cancer to increase the activity of GEM and improve the prognosis of pancreatic cancer.

METHODS AND RESULTS

GEM-resistant PANC-1 cells were treated with increasing doses of GEM. The effects of GEM and TET on apoptosis were evaluated by flow cytometry and Hoechst 33258 staining. We also evaluated the expression of survivin by real-time PCR, and the expression levels of proteins involved in apoptosis, autophagy, and PI3K/Akt/mTOR signaling were detected by western blotting. The results showed that TET downregulated expression of survivin by inhibiting the PI3K/Akt/mTOR signaling pathway to promote pancreatic cancer cell apoptosis, thereby enhancing pancreatic cancer cell sensitivity to GEM. Moreover, TET enhanced cytotoxic and autophagy-dependent cell death by upregulating the AMPK-autophagy axis, and this effect was reversed by inhibition of AMPK.

CONCLUSIONS

TET promotes apoptosis by inhibiting the PI3K/Akt/mTOR signaling pathway and promotes autophagy via up-regulating the AMPK signaling pathway to play an anti-tumor effect in GEM-resistant pancreatic cancer cells, which represents a new therapeutic strategy for the treatment of GEM-resistant pancreatic cancer.

Mesothelin blockage by Amatuximab suppresses cell invasiveness, enhances gemcitabine sensitivity and regulates cancer cell stemness in mesothelin-positive pancreatic cancer cells

BACKGROUND

Mesothelin is a 40-kDa glycoprotein that is highly overexpressed in various types of cancers, however molecular mechanism of mesothelin has not been well-known. Amatuximab is a chimeric monoclonal IgG1/k antibody targeting mesothelin. We recently demonstrated that the combine therapy of Amatuximab and gemcitabine was effective for peritonitis of pancreatic cancer in mouse model.

METHODS

We discover the role and potential mechanism of mesothelin blockage by Amatuximab in human pancreatic cells both expressing high or low level of mesothelin in vitro experiment and peritonitis mouse model of pancreatic cancer.

RESULTS

Mesothelin blockage by Amatuximab lead to suppression of invasiveness and migration capacity in AsPC-1 and Capan-2 (high mesothelin expression) and reduce levels of pMET expression. The combination of Amatuximab and gemcitabine suppressed proliferation of AsPC-1 and Capan-2 more strongly than gemcitabine alone. These phenomena were not observed in Panc-1 and MIA Paca-2 (Mesothelin low expression). We previously demonstrated that Amatuximab reduced the peritoneal mass in mouse AsPC-1 peritonitis model and induced sherbet-like cancer cell aggregates, which were vanished by gemcitabine. In this study, we showed that the cancer stem cell related molecule such as ALDH1, CD44, c-MET, as well as proliferation related molecules, were suppressed in sherbet-like aggregates, but once sherbet-like aggregates attached to peritoneum, they expressed these molecules strongly without the morphological changes.

CONCLUSIONS

Our work suggested that Amatuximab inhibits the adhesion of cancer cells to peritoneum and suppresses the stemness and viability of those, that lead to enhance the sensitivity for gemcitabine.

Endovascular implantation of iodine-125 seed strand combined and stent placement for locally advanced pancreatic ductal adenocarcinoma with vascular invasion: a prospective single-arm pilot study

Purpose

To investigate the safety and feasibility of endovascular brachytherapy using iodine-125 (¹²⁵I) seed strand for locally advanced pancreatic ductal adenocarcinoma (PDAC) with vascular invasion.

Material and methods

From January 2010 to January 2015, 12 patients diagnosed with locally advanced, inoperable PDAC with splenic or superior mesenteric vein invasion were enrolled in the present study and received endovascular brachytherapy combined with regional intra-arterial infusion chemotherapy. Standardized software was used for dose calculation. Procedure-related and radiation complications were documented and assessed. Overall survival was calculated with the Kaplan-Meier approach.

Results

The technical success rate of ¹²⁵I seed strand implantation and stent placement was 100%. During follow-up with a mean duration of 17.00 ±6.07 months (range, 6~24 months), the mean and median survival times were 12.0 ±2.4 months (95% CI: 7.4~16.6 months) and 10.7 ±1.4 months (95% CI: 8.0~13.5 months), respectively. One month after the treatment, the disease control and objective rates were 83.8% and 58.3%, respectively. The 6-, 12-, and 15-month cumulative survival rates were 66.7%, 47.6%, and 9.5%, respectively.

Conclusions

Endovascular brachytherapy using ¹²⁵I seed strand and stent placement may be a safe and effective treatment option for locally advanced pancreatic duct adenocarcinoma with vascular invasion.

LLGL1 Regulates Gemcitabine Resistance by Modulating the ERK-SP1-OSMR Pathway in Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS

Gemcitabine resistance is rapidly acquired by pancreatic ductal adenocarcinoma (PDAC) patients. Novel approaches that predict the gemcitabine response of patients and enhance gemcitabine chemosensitivity are important to improve patient survival. We aimed to identify genes as novel biomarkers to predict the gemcitabine response and the therapeutic targets to attenuate chemoresistance in PDAC cells.

METHODS

Genome-wide RNA interference screening was conducted to identify genes that regulated gemcitabine chemoresistance. A cell proliferation assay and a tumor formation assay were conducted to study the role of lethal giant larvae homolog 1 (LLGL1) in gemcitabine chemoresistance. Levels of LLGL1 and its regulating targets were measured by immunohistochemical staining in tumor tissues obtained from patients who received gemcitabine as a single therapeutic agent. A gene-expression microarray was conducted to identify the targets regulated by LLGL1.

RESULTS

Silencing of LLGL1 markedly reduced the gemcitabine chemosensitivity in PDAC cells. Patients had significantly shorter survival (6 months) if they bore tumors expressing low LLGL1 level than tumors with high LLGL1 level (20 months) (hazard ratio, 0.1567; 95% CI, 0.05966-0.4117). Loss of LLGL1 promoted cytokine receptor oncostatin M receptor (OSMR) expression in PDAC cells that led to gemcitabine resistance, while knockdown of OSMR effectively rescued the chemoresistance phenotype. The LLGL1-OSMR regulatory pathway showed great clinical importance because low LLGL1 and high OSMR expressions were observed frequently in PDAC tissues. Silencing of LLGL1 induced phosphorylation of extracellular signal-regulated kinase 2 and specificity protein 1 (Sp1), promoted Sp1 (pThr453) binding at the OSMR promoter, and enhanced OSMR transcription.

CONCLUSIONS

LLGL1 possessed a tumor-suppressor role as an inhibitor of chemoresistance by regulating OSMR-extracellular signal-regulated kinase 2/Sp1 signaling. The data sets generated and analyzed during the current study are available in the Gene Expression Omnibus repository (ID: GSE64681).

Role of oncogenic KRAS in the diagnosis, prognosis and treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is predicted to be the second most common cause of death within the next 10 years. The prognosis for this disease is poor despite diagnostic progress and new chemotherapeutic regimens. The oncogenic KRAS mutation is the major event in pancreatic cancer; it confers permanent activation of the KRAS protein, which acts as a molecular switch to activate various intracellular signalling pathways and transcription factors inducing cell proliferation, migration, transformation and survival. Several laboratory methods have been developed to detect KRAS mutations in biological samples, including digital droplet PCR (which displays high sensitivity). Clinical studies have revealed that a KRAS mutation assay in fine-needle aspiration material combined with cytopathology increases the sensitivity, accuracy and negative predictive value of cytopathology for a positive diagnosis of pancreatic cancer. In addition, the presence of KRAS mutations in serum and plasma (liquid biopsies) correlates with a worse prognosis. The presence of mutated KRAS can also have therapeutic implications, whether at the gene level per se, during its post-translational maturation, interaction with nucleotides and after activation of the various oncogenic signals. Further pharmacokinetic and toxicological studies on new molecules are required, especially small synthetic molecules, before they can be used in the therapeutic arsenal for pancreatic ductal adenocarcinoma.

Impact of ethanolic extract of Equisetum arvense (EA1) on pancreatic carcinoma AsPC-1 cells

The current research was focused on evaluation of the cytotoxic and suppressive action of ethanolic extract of Equisetum arvense (EA1) against human pancreatic carcinoma cell line ASPC-1 after treatment with 25 µg/mL, 50 µg/mL, 100 µg/mL and 200 µg/mL EA1, using MTT assay and Antioxidant activity. Detailed investigations led to reveal the ability of cell patronage through the dreadful upshot of free radicals. The current approach followed MTT assays to examine the long-lasting ability and growth of cells as EA1 restrained the cell viability and growth of ASPC-1. At the end, EA1 showed its potential cytotoxicity and reduced the cellular proliferation of ASPC-1 cells through a pattern, which appeared to be concentration dependent. Our results can form the basis to explore the molecular mechanisms underlying Ethanolic Extract of Equisetum arvense induced cell death in pancreatic cancer cell lines and may serve as an alternative anticancer agent for the treatment of pancreatic carcinoma (PC) with no or least side effects to the patient.

Hyaluronic Acid-Based Multilayer Films Regulate Hypoxic Multicellular Aggregation of Pancreatic Cancer Cells with Distinct Cancer Stem-Cell-like Properties

In vitro spherical cancer models have been widely used in cancer stem cell (CSC) research, and the ability of CSCs to form multicellular colonies is recognized as a morphological marker. However, although several spherical/colony models share a common three-dimensional (3D) conformation, each model displays its own intrinsic properties. Thus, the CSC phenotypes with distinct multicellular aggregate morphologies must be defined and clarified. Here, a novel 3D model was designed to regulate the type of pancreatic CSC colonies that form using niche mimetic hyaluronic acid (HA)-based multilayer nanofilms and hypoxia. The multicellular aggregate morphology, CSC phenotypes, CSC-related marker expression, cell cycle, invasion, and drug resistance were determined. On the basis of the results of a cell morphology analysis, colonies formed on multilayer nanofilms in response to both normoxia and hypoxia, but round and island-type colonies, were investigated. Immunostaining results revealed a significantly higher expression of stem cell markers, such as OCT4, CXCR4, and CD44v6, in colonies that formed on multilayer nanofilms. These colonies also expressed higher levels of E-cadherin, hypoxia-inducible factor-1α, and vimentin, particularly the round-type colonies that formed on HA-based multilayer nanofilms, [poly(allylamine) (PAH)/HA]₃, indicating that these colonies exhibit hybrid and metastable epithelial/mesenchymal phenotypes. Moreover, the cell cycle and invasion tests revealed that most of the cells in colonies growing on multilayer nanofilms showed a quiescent, slow cycling phenotype but displayed higher invasion after induction. Furthermore, a hypoxic environment strongly influences the drug resistance. This study describes a useful tool to investigate the diverse phenotypes of pancreatic CSC colonies and to study their regulatory factors that may benefit CSC research.

MicroRNA-221 induces autophagy through suppressing HDAC6 expression and promoting apoptosis in pancreatic cancer

Pancreatic cancer is an aggressive type of cancer with a poor prognosis, short survival rate and high mortality. Therefore, understanding the molecular mechanism underlying the aggressive growth of pancreatic cancer is of importance. An increasing number of studies suggest that numerous microRNAs (miRNAs/miRs) are associated with the tumorigenesis, progression and prognosis of tumors. In a recent study by the present authors, it was revealed that the expression of miR-221 was significantly downregulated in highly aggressive pancreatic cancer cells compared with weakly aggressive pancreatic cancer cells. In addition, miR-221 has been suggested as a novel tumor-associated miRNA, as it is involved in apoptosis, invasion, metastasis and autophagy of tumor cells. However, the function of miR-221 in pancreatic cancer remains yet to be investigated. In the present study, it was revealed that transfection with miR-221 mimic was able to significantly induce apoptosis and autophagy in pancreatic cancer cells compared with the negative control. The protein deacetylase histone deacetylase-6 (HDAC6) has emerged to be an important component in the cellular management of protein aggregates. Studies suggest that HDAC6 serves a function in the clearance of aggresomes, thereby implying a functional association between HDAC6 and autophagy. In the present study, it was revealed that transfection with miR-221 mimic was able to suppress the protein expression of HDAC6 in pancreatic cancer cells compared with the negative control. Immunofluorescence data suggested that the inhibition of HDAC6 was able to induce autophagy in pancreatic cancer cells. Additionally, the results of the present study suggest that the downregulation of miR-221 expression may serve an oncogenic function in the apoptosis and autophagy of pancreatic cancer cells by inducing the expression of HDAC6.

Effect of arenobufagin on human pancreatic carcinoma cells

Pancreatic carcinoma (PC) is a deadly form of cancer with poor overall survival. Currently, chemotherapy such as gemcitabine and 5-fluorouracil (5-FU) are the most popular medications that can improve survival, but rapid drug-resistance makes the search for more effective drugs urgent. Upon looking for natural components to treat PC, it was found that arenobufagin, a cardiac glycosides-like compound, showed significant effects on the gemcitabine-resistant pancreatic carcinoma cell line Panc-1 and the gemcitabine-sensitive cell line ASPC-1 at nanomolar concentrations. The present study used MTT and clonogenic survival assays to examine survival and proliferation, and western blotting to assess changes in the associated mitogen activated protein kinase and phosphoinositide 3-kinase pathways and expression of apoptosis-related proteins. The current study also detected the cell cycle by flow cytometry. Arenobufagin inhibited cell survival and proliferation, decreased the phosphorylation of key downstream proteins of K-Ras, including protein kinase B and extracellular signal related kinase, induced cell cycle G2/M phase arrest and apoptosis, and downregulated the level of phosphorylated epidermal growth factor receptor. Notably, the present data also showed that arenobufagin can enhance the sensitivity of PC cells to gemcitabine and 5-FU. In conclusion, arenobufagin could enhance the effect of gemcitabine and 5-FU on PC cells by targeting multiple key proteins. Therefore, arenobufagin has potential as anadjuvant therapy for the treatment of PC.

Gene Therapy for Pancreatic Cancer: Specificity, Issues and Hopes

A recent death projection has placed pancreatic ductal adenocarcinoma as the second cause of death by cancer in 2030. The prognosis for pancreatic cancer is very poor and there is a great need for new treatments that can change this poor outcome. Developments of therapeutic innovations in combination with conventional chemotherapy are needed urgently. Among innovative treatments the gene therapy offers a promising avenue. The present review gives an overview of the general strategy of gene therapy as well as the limitations and stakes of the different experimental in vivo models, expression vectors (synthetic and viral), molecular tools (interference RNA, genome editing) and therapeutic genes (tumor suppressor genes, antiangiogenic and pro-apoptotic genes, suicide genes). The latest developments in pancreatic carcinoma gene therapy are described including gene-based tumor cell sensitization to chemotherapy, vaccination and adoptive immunotherapy (chimeric antigen receptor T-cells strategy). Nowadays, there is a specific development of oncolytic virus therapies including oncolytic adenoviruses, herpes virus, parvovirus or reovirus. A summary of all published and on-going phase-1 trials is given. Most of them associate gene therapy and chemotherapy or radiochemotherapy. The first results are encouraging for most of the trials but remain to be confirmed in phase 2 trials.

Ku70 inhibits gemcitabine-induced DNA damage and pancreatic cancer cell apoptosis

The current study focused on the role of Ku70, a DNA-dependent protein kinase (DNA-PK) complex protein, in pancreatic cancer cell resistance to gemcitabine. In both established cell lines (Mia-PaCa-2 and PANC-1) and primary human pancreatic cancer cells, shRNA/siRNA-mediated knockdown of Ku70 significantly sensitized gemcitabine-induced cell death and proliferation inhibition. Meanwhile, gemcitabine-induced DNA damage and subsequent pancreatic cancer cell apoptosis were also potentiated with Ku70 knockdown. On the other hand, exogenous overexpression of Ku70 in Mia-PaCa-2 cells suppressed gemcitabine-induced DNA damage and subsequent cell apoptosis. In a severe combined immune deficient (SCID) mice Mia-PaCa-2 xenograft model, gemcitabine-induced anti-tumor activity was remarkably pontificated when combined with Ku70 shRNA knockdown in the xenografts. The results of this preclinical study imply that Ku70 might be a primary resistance factor of gemcitabine, and Ku70 silence could significantly chemo-sensitize gemcitabine in pancreatic cancer cells.

micorRNA-101 silences DNA-PKcs and sensitizes pancreatic cancer cells to gemcitabine

Gemcitabine sensitization is important for the treatment of pancreatic cancer. We have previously shown that DNA-dependent protein kinase catalytic subunit (DNA-PKcs) over-expression causes Akt activation and gemcitabine resistance in pancreatic cancer cells. Here, we aim to downregulate DNA-PKcs via introduction of micorRNA-101 ("miR-101"). We showed that forced-expression of miR-101 downregulated DNA-PKcs and potentiated gemcitabine-induced PANC-1 pancreatic cancer cell death and apoptosis. Contrarily, miR-101 depletion through expressing antagomiR-101 in PANC-1 cells resulted in DNA-PKcs upregulation and gemcitabine resistance. DNA-PKcs downregulation is the primary reason of gemcitabine-sensitization by miR-101. DNA-PKcs inhibition (by NU7026) or silence (by targeted siRNAs) disabled miR-101-mediaetd gemcitabine sensitization. Significantly, Akt Ser-473 phosphorylation in PANC-1 cells was also inhibited by miR-101, but was augmented with antagomiR-101 expression. Importantly, we showed that miR-101 level was downregulated in gemcitabine-resistant human pancreatic cancer tissues, which was correlated with DNA-PKcs upregulation. Together, these results suggest that miR-101 sensitizes PANC-1 cells to gemcitabine possibly via downregulating DNA-PKcs.

The mitochondrion interfering compound NPC-26 exerts potent anti-pancreatic cancer cell activity in vitro and in vivo

The development of novel anti-pancreatic cancer agents is extremely important. Here, we investigated the anti-pancreatic cancer activity by NPC-26, a novel mitochondrion interfering compound. We showed that NPC-26 was anti-proliferative and cytotoxic to human pancreatic cancer cells, possibly via inducing caspase-9-dependent cell apoptosis. Pharmacological inhibition or shRNA-mediated silence of caspase-9 attenuated NPC-26-induced pancreatic cancer cell death and apoptosis. Further, NPC-26 treatment led to mitochondrial permeability transition pore (mPTP) opening in the cancer cells, which was evidenced by mitochondrial depolarization, ANT-1(adenine nucleotide translocator-1)-Cyp-D (cyclophilin-D) association and oxidative phosphorylation disturbance. mPTP blockers (cyclosporin and sanglifehrin A) or shRNA-mediated knockdown of key mPTP components (Cyp-D and ANT-1) dramatically attenuated NPC-26-induced pancreatic cancer cell apoptosis. Importantly, we showed that NPC-26, at a low concentration, potentiated gemcitabine-induced mPTP opening and subsequent pancreatic cancer cell apoptosis. In vivo, NPC-26 intraperitoneal injection significantly suppressed the growth of PANC-1 xenograft tumors in nude mice. Meanwhile, NPC-26 sensitized gemcitabine-mediated anti-pancreatic cancer activity in vivo. In summary, the results of this study suggest that NPC-26, alone or together with gemcitabine, potently inhibits pancreatic cancer cells possibly via disrupting mitochondrion.

Short-chain C6 ceramide sensitizes AT406-induced anti-pancreatic cancer cell activity

Our previous study has shown that AT406, a first-in-class small molecular antagonist of IAPs (inhibitor of apoptosis proteins), inhibits pancreatic cancer cell proliferation in vitro and in vivo. The aim of this research is to increase AT406's sensitivity by adding short-chain C6 ceramide. We show that co-treatment of C6 ceramide dramatically potentiated AT406-induced caspase/apoptosis activation and cytotoxicity in established (Panc-1 and Mia-PaCa-2 lines) and primary human pancreatic cancer cells. Reversely, caspase inhibitors largely attenuated C6 ceramide plus AT406-induced above cancer cell death. Molecularly, C6 ceramide downregulated Bcl-2 to increase AT406's sensitivity in pancreatic cancer cells. Intriguingly, C6 ceramide-mediated AT406 sensitization was nullified with Bcl-2 shRNA knockdown or pretreatment of the Bcl-2 inhibitor ABT-737. In vivo, liposomal C6 ceramide plus AT406 co-administration dramatically inhibited Panc-1 xenograft tumor growth in severe combined immunodeficient (SCID) mice. The combined anti-tumor activity was significantly more potent than either single treatment. Expressions of IAPs (cIAP1/XIAP) and Bcl-2 were downregulated in Panc-1 xenografts with the co-administration. Together, we demonstrate that C6 ceramide sensitizes AT406-mediated anti-pancreatic cancer cell activity possibly via downregulating Bcl-2.

The small-molecule IAP antagonist AT406 inhibits pancreatic cancer cells in vitro and in vivo

In the present study, we tested the anti-pancreatic cancer activity by AT406, a small-molecule antagonist of IAP (inhibitor of apoptosis proteins). In established (Panc-1 and Mia-PaCa-2 lines) and primary human pancreatic cancer cells, treatment of AT406 significantly inhibited cell survival and proliferation. Yet, same AT406 treatment was non-cytotoxic to pancreatic epithelial HPDE6c7 cells. AT406 increased caspase-3/-9 activity and provoked apoptosis in the pancreatic cancer cells. Reversely, AT406' cytotoxicity in these cells was largely attenuated with pre-treatment of caspase inhibitors. AT406 treatment caused degradation of IAP family proteins (cIAP1 and XIAP) and release of cytochrome C, leaving Bcl-2 unaffected in pancreatic cancer cells. Bcl-2 inhibition (by ABT-737) or shRNA knockdown dramatically sensitized Panc-1 cells to AT406. In vivo, oral administration of AT406 at well-tolerated doses downregulated IAPs (cIAP1/XIAP) and inhibited Panc-1 xenograft tumor growth in severe combined immunodeficient (SCID) nude mice. Together, our preclinical results suggest that AT406 could be further evaluated as a promising anti-pancreatic cancer agent.

The preclinical evaluation of TIC10/ONC201 as an anti-pancreatic cancer agent

Here we evaluated the potential anti-pancreatic cancer activity by TIC10/ONC201, a first-in-class small-molecule inducer of tumor necrosis (TNF)-related apoptosis-inducing ligand (TRAIL). The in vitro results showed that TIC10 induced potent cytotoxic and cytostatic activities in several human pancreatic cancer cell lines (Panc-1, Mia-PaCa2, AsPC-1 or L3.6). TIC10 activated both extrinsic (TRAIL-caspase-8-dependent) and endogenous/mitochondrial (caspase-9-dependent) apoptosis pathways in the pancreatic cancer cells. Molecularly, we showed that TIC10 inhibited Akt-Erk activation, yet induced TRAIL expression in pancreatic cancer cells. Significantly, TIC10, at a relatively low concentration, sensitized gemcitabine-induced growth inhibition and apoptosis against pancreatic cancer cells. Further, TIC10 and gemcitabine synergistically inhibited Panc-1 xenograft growth in SCID mice. The combination treatment also significantly improved mice survival. In addition, Akt-Erk in-activation and TRAIL/cleaved-caspase-8 induction were observed in TIC10-treated Panc-1 xenografts. Together, the preclinical results of the study demonstrate the potent anti-pancreatic cancer activity by TIC10, or with gemcitabine.

MiR-29c inhibits cell growth, invasion, and migration of pancreatic cancer by targeting ITGB1

MiR-29c is frequently dysregulated in many cancers; however, the roles of miR-29c in pancreatic cancer (PC) and underlying mechanisms remain poorly understood. In this study, we investigated the role of miR-29c in PC. Using quantitative real-time polymerase chain reaction, we demonstrated that miR-29c was frequently downregulated in clinical PC tissues and cell lines. Overexpression of miR-29c significantly inhibited the proliferation, migration, and invasion of PC cells in vitro, which demonstrated that miR-29c acts as a tumor suppressor in PC cells. Further analysis revealed that ITGB1 is one of the functional target genes of miR-29c, and knockdown of ITGB1 inhibited the proliferation, migration, and invasion of PC cells, which was similar to the effects of overexpression of miR-29c. Taken together, our results highlight the significance of miR-29c–ITGB1 interaction in the development and progression of PC.

Targeting pancreatic cancer cells by a novel hydroxamate-based histone deacetylase (HDAC) inhibitor ST-3595

In the current study, we tested the potential anti-pancreatic cancer activity of a novel hydroxamate-based histone deacetylase (HDAC) inhibitor ST-3595. We showed that ST-3595 exerted potent anti-proliferative and cytotoxic activities against both established pancreatic cancer cell lines (PANC-1, AsPC-1, and Mia-PaCa-2), and patient-derived primary cancer cells. It was, however, generally safe to non-cancerous pancreatic epithelial HPDE6c7 cells. ST-3595-induced cytotoxicity to pancreatic cancer cells was associated with significant apoptosis activation. Reversely, the pan caspase inhibitor z-VAD-fmk and the caspase-8 inhibitor z-ITED-fmk alleviated ST-3595-mediated anti-pancreatic cancer activity in vitro. For the mechanism study, ST-3595 inhibited HDAC activity, and induced mitochondrial permeability transition pore (MPTP) opening in pancreatic cancer cells. Inhibition of MPTP, by cyclosporin A, sanglifehrin A, or by cyclophilin-D (Cyp-D) siRNA knockdown, dramatically inhibited ST-3595-induced pancreatic cancer cell apoptosis. Meanwhile, we found that a low concentration of ST-3595 dramatically sensitized gemcitabine-induced anti-pancreatic cancer cell activity in vitro. In vivo, ST-3595 oral administration inhibited PANC-1 xenograft growth in nude mice, and this activity was further enhanced when in combination with gemcitabine. In summary, the results of this study suggest that targeting HDACs by ST-3595 might represent as a novel and promising anti-pancreatic cancer strategy.

Embigin is overexpressed in pancreatic ductal adenocarcinoma and regulates cell motility through epithelial to mesenchymal transition via the TGF-β pathway

Embigin is a member of the immunoglobulin superfamily and encodes a transmembrane glycoprotein. There have been reports of Embigin involvement in neuromuscular junction formation and plasticity; however, the molecular functions of Embigin in other organs are unknown. Our aim was to investigate the possible role of Embigin in pancreatic cancer. In pancreatic ductal adenocarcinoma tissues, Embigin expression was higher than that in normal pancreatic tissues. Immunohistochemical analysis revealed expression of Embigin in pancreatic cancer cells, as well as expression of monocarboxylate transporter 2 (MCT2) in cancer tissues. To gain further insight, we transfected BxPC-3 and HPAC pancreatic cancer cells with siRNA or shRNA targeting Embigin and observed reductions in cell proliferation, migration, invasion, wound healing, and reduced levels of matrix metalloproteinases-2 and -9. Silencing of Embigin increased intracellular L-lactate concentration by 1.5-fold and decreased MCT2 levels at the plasma membrane. Furthermore, Embigin silencing led to a reduced expression of PI3K, GSK3-β, and Snail/Slug. Upon treating BxPC-3 cells with transforming growth factor-β (TGF-β), we observed elevated expression of Snail/Slug, Embigin, and Vimentin; meanwhile, when treating cells with SB-216763, a GSK3-β inhibitor, we noted decreases in GSK3-β, Snail/Slug, and Embigin expression, suggesting that the TGF-β signaling cascade, comprising PI3K, GSK3-β, Snail/Slug, and Embigin signals, mediates epithelial to mesenchymal transition (EMT) in pancreatic cancer cells. These findings indicate the involvement of Embigin in EMT in pancreatic cancer progression and suggest Embigin as a putative target for the detection and/or treatment of pancreatic cancer.

The glucosylceramide synthase inhibitor PDMP sensitizes pancreatic cancer cells to MEK/ERK inhibitor AZD-6244

Here we show that d,l-Threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), a glycosphingolipid biosynthesis inhibitor, increases the sensitivity of pancreatic cancer cells to the novel MEK-ERK inhibitor AZD-6244. AZD-6244 and PDMP co-administration induced massive pancreatic cancer cell death and apoptosis, more potently than either drug alone. We discovered that AZD-6244 induced ceramide production in pancreatic cancer cells, yet the excess ceramide was metabolically removed in the long-term (24-48h). PDMP facilitated AZD-6244-induced ceramide production, and ceramide level remained elevated up to 48h. Meanwhile, exogenously-added cell-permeable short chain ceramide (C2) similarly sensitized AZD-6244's activity, the two caused substantial pancreatic cancer cell death and apoptosis. At the molecular level, PDMP and AZD-6244 co-treatment inactivated ERK1/2 and AKT-mTOR signalings simultaneously in pancreatic cancer cells, while either agent alone only affected one signaling. In summary, PDMP significantly increased the sensitivity of AZD-6244 in pancreatic cancer cells. This appears to involve a sustained ceramide production as well as concurrent block of ERK and AKT-mTOR signalings.

GDC-0980-induced apoptosis is enhanced by autophagy inhibition in human pancreatic cancer cells

Pancreatic cancer remains fatal to the fast majority of affected patients. Activation of phosphoinositide-3 kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) pathway plays an important role in pancreatic cancer progression and chemo-resistance. In the present study, we examined the activity of GDC-0980, a novel class I PI3K/mTOR kinase inhibitor, against pancreatic cancer cells in vitro. GDC-0980 inhibited AKT-mTOR activation and pancreatic cancer cell (PANC-1 and Capan-1 lines) survival. In both cancer cell lines, GDC-0980 simultaneously activated apoptosis and autophagy, the latter was detected by p62 degradation, Beclin-1 upregulation and light chain 3B (LC3B) conversion from a cytosolic (LC3B-I) to a membrane-bound (LC3B-II) form. Autophagy inhibitors including 3-methyladenine, hydroxychloroquine, NH4Cl and bafilomycin A1 enhanced apoptosis and cytotoxicity by GDC-0980, such an effect was reversed by caspase inhibitors (z-VAD-FMK and z-ITED-FMK). Furthermore, knockdown of LC3B or Beclin-1 through siRNA increased GDC-0980-induced anti-pancreatic cancer cell activity. Thus, inhibition of autophagy sensitizes GDC-0980-induced anti-pancreatic cancer activity, suggesting a novel therapeutic strategy for GDC-0980 sensitization.

Radiation plus docetaxel and cisplatin in locally advanced pancreatic carcinoma: a non-comparative randomized phase II trial

BACKGROUND

We performed a randomized, non-comparative phase II study evaluating docetaxel in combination with either daily continuous (protracted IV) 5-fluorouracil or cisplatin administered weekly, concurrent to radiotherapy in the treatment of locally advanced pancreatic carcinoma. Results of the docetaxel plus cisplatin regimen are reported.

METHODS

Forty chemotherapy-naive patients with locally advanced pancreatic carcinoma were randomly assigned to receive 5-fluorouracil and docetaxel or docetaxel 20mg/m(2) and cisplatin 20mg/m(2)/week, plus concurrent radiotherapy for 6 weeks. The radiation dose to the primary tumour was 54Gy in 30 fractions. The trial's primary endpoint was the 6-month crude non-progression rate.

RESULTS

51 patients from 7 centres were included in the docetaxel-cisplatin treatment group. Six-month non-progression rate was 39% (95% confidence interval: 26-53). Median overall survival was 9.6 months (95% confidence interval: 2.4-60.7); 6 complete and 8 partial responses were obtained. Six patients survived more than 2 years after their inclusion in the trial. Grade ≥3 toxicity was reported in 63% of patients; no treatment-related death occurred. Severe toxicities were mainly anorexia (22%), vomiting (20%) and fatigue (24%).

CONCLUSIONS

Despite inadequate efficacy according to the main end point, this regimen gave a satisfactory rate of objective response (27%) with tolerable toxicity.

DNA-PKcs is important for Akt activation and gemcitabine resistance in PANC-1 pancreatic cancer cells

Pancreatic cancer is one of the most aggressive human malignancies with extremely poor prognosis. The moderate activity of the current standard gemcitabine and gemcitabine-based regimens was due to pre-existing or acquired chemo-resistance of pancreatic cancer cells. In this study, we explored the potential role of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in gemcitabine resistance, and studied the underlying mechanisms. We found that NU-7026 and NU-7441, two DNA-PKcs inhibitors, enhanced gemcitabine-induced cytotoxicity and apoptosis in PANC-1 pancreatic cancer cells. Meanwhile, PANC-1 cells with siRNA-knockdown of DNA-PKcs were more sensitive to gemcitabine than control PANC-1 cells. Through the co-immunoprecipitation (Co-IP) assay, we found that DNA-PKcs formed a complex with SIN1, the latter is an indispensable component of mammalian target of rapamycin (mTOR) complex 2 (mTORC2). DNA-PKcs-SIN1 complexation was required for Akt activation in PANC-1 cells, while inhibition of this complex by siRNA knockdown of DNA-PKcs/SIN1, or by DNA-PKcs inhibitors, prevented Akt phosphorylation in PANC-1 cells. Further, SIN1 siRNA-knockdown also facilitated gemcitabine-induced apoptosis in PANC-1 cells. Finally, DNA-PKcs and p-Akt expression was significantly higher in human pancreatic cancer tissues than surrounding normal tissues. Together, these results show that DNA-PKcs is important for Akt activation and gemcitabine resistance in PANC-1 pancreatic cancer cells.

Cryosurgery for pancreatic cancer

The procedure of pancreatic cryosurgery is performed with intraoperative or percutaneous approaches. Based on current data and our initial experience, cryoablation appears to be a feasible, potentially safe and promising option in patients with locally advanced and unresectable pancreatic cancer. It is suggested that there are almost no known contraindications to the use of cryosurgery for pancreatic cancer. For most patients with pancreatic cancer, cryosurgery can substitute conventional surgery.

The novel mTORC1/2 dual inhibitor INK-128 suppresses survival and proliferation of primary and transformed human pancreatic cancer cells

Pancreatic cancer has one of worst prognosis among all human malignancies around the world, the development of novel and more efficient anti-cancer agents against this disease is urgent. In the current study, we tested the potential effect of INK-128, a novel mammalian target of rapamycin (mTOR) complex 1 and 2 (mTORC1/2) dual inhibitor, against pancreatic cancer cells in vitro. Our results demonstrated that INK-128 concentration- and time-dependently inhibited the survival and growth of pancreatic cancer cells (both primary cells and transformed cells). INK-128 induced pancreatic cancer cell apoptosis and necrosis simultaneously. Further, INK-128 dramatically inhibited phosphorylation of 4E-binding protein 1 (4E-BP1), ribosomal S6 kinase 1 (S6K1) and Akt at Ser 473 in pancreatic cancer cells. Meanwhile, it downregulated cyclin D1 expression and caused cell cycle arrest. Finally, we found that a low concentration of INK-128 significantly increased the sensitivity of pancreatic cancer cells to gemcitabine. Together, our in vitro results suggest that INK-128 might be further investigated as a novel anti-cancer agent or chemo-adjuvant for pancreatic cancer treatment.

miR-203 inhibits tumor cell migration and invasion via caveolin-1 in pancreatic cancer cells

Pancreatic cancer is one of the most lethal malignant diseases with the poorest prognosis and is the fourth leading cause of tumor-associated mortality in the industrialized world. microRNAs (miRNAs or miRs) are small noncoding RNAs of approximately 22 nucleotides long that are able to function as oncogenes or tumor suppressors in human cancer. In our study, overexpression of miR-203 in Panc-1 cells is sufficient to reduce migratory ability and invasiveness, and to induce upregulation of epithelial markers (Snail, ZO-1 and β-catenin) followed by a decrease of mesenchymal marker expression (Zeb-1, vimentin and fibronectin). We also found that the caveolin-1 mRNA or protein levels are modulated by miR-203 in Panc-1 cells. We found that exogenous miR-203 altered the level of cell migration and invasion, and the expression of associated proteins following caveolin-1 knockdown by small interfering RNA. These results demonstrate that miR-203 inhibits cell migration and invasion via caveolin-1 in pancreatic cancer cells, suggest that miR-203 expression may be a useful indicator of the metastatic potential and provide a new therapeutic target in this common malignancy.

Inhibiting signal transducer and activator of transcription-3 increases response to gemcitabine and delays progression of pancreatic cancer

Background

Among the solid tumors, human pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis. Gemcitabine is the standard first line of therapy for pancreatic cancer but has limited efficacy due to inherent or rapid development of resistance and combining EGFR inhibitors with this regimen results in only a modest clinical benefit. The goal of this study was to identify molecular targets that are activated during gemcitabine therapy alone or in combination with an EGFR inhibitor.

Methods

PDAC cell lines were used to determine molecular changes and rates of growth after treatment with gemcitabine or an EGFR inhibitor, AG1478, by Western blot analysis and MTT assays respectively. Flow cytometric analysis was performed to study the cell cycle progression and rate of apoptosis after gemcitabine treatment. ShRNA was used to knockdown STAT3. An in vivo orthotopic animal model was used to evaluate STAT3 as a target. Immunohistochemical analysis was performed to analyze Ki67 and STAT3 expression in tumors.

Results

Treatment with gemcitabine increased the levels of EGFR^Tyr1068 and ERK phosphorylation in the PDAC cell lines tested. The constitutive STAT3^Tyr705 phosphorylation observed in PDAC cell lines was not altered by treatment with gemcitabine. Treatment of cells with gemcitabine or AG1478 resulted in differential rate of growth inhibition. AG1478 efficiently blocked the phosphorylation of EGFR^Tyr1068 and inhibited the phosphorylation of down-stream effectors AKT and ERKs, while STAT3^Tyr705 phosphorylation remained unchanged. Combining these two agents neither induced synergistic growth suppression nor inhibited STAT3^Tyr705 phosphorylation, thus prompting further studies to assess whether targeting STAT3 improves the response to gemcitabine or AG1478. Indeed, knockdown of STAT3 increased sensitivity to gemcitabine by inducing pro-apoptotic signals and by increasing G1 cell cycle arrest. However, knockdown of STAT3 did not enhance the growth inhibitory potential of AG1478. In vivo orthotopic animal model results show that knockdown of STAT3 caused a significant reduction in tumor burden and delayed tumor progression with increased response to gemcitabine associated with a decrease in the Ki-67 positive cells.

Conclusions

This study suggests that STAT3 should be considered an important molecular target for therapy of PDAC for enhancing the response to gemcitabine.

Pancreatic cancer cells surviving gemcitabine treatment express markers of stem cell differentiation and epithelial-mesenchymal transition

Objective response rates to standard chemotherapeutic regimens remain low in pancreatic cancer. Subpopulations of cells have been identified in various solid tumors which express stem cell-associated markers and are associated with increased resistance against radiochemotherapy. We investigated the expression of stem cell genes and markers of epithelial-mesenchymal transition in pancreatic cancer cells that survived high concentrations of gemcitabine treatment. Capan-1 and Panc-1 cells were continuously incubated with 1 and 10 µM gemcitabine. Surviving cells were collected after 1, 3 and 6 days. Expression of PDX-1, SHH, CD24, CD44, CD133, EpCAM, CBX7, OCT4, SNAIL, SLUG, TWIST, Ki-67, E-cadherin, β-catenin and vimentin were quantified by qPCR or immunocytochemistry. Migration was assessed by wound‑healing assay. SHH was knocked down using RNA interference. Five primary pancreatic cancer cell lines were used to validate the qPCR results. All investigated genes were upregulated after 6 days of gemcitabine incubation. Highest relative expression levels were observed for OCT4 (13.4-fold), CD24 (47.3-fold) and EpCAM (15.9-fold) in Capan-1 and PDX-1 (13.3‑fold), SHH (24.1-fold), CD44 (17.4-fold), CD133 (20.2-fold) and SLUG (15.2-fold) in Panc-1 cells. Distinct upregulation patterns were observed in the primary cells. Migration was increased in Panc-1 cells and changes in the expression of E-cadherin and β-catenin were typical of epithelial-mesenchymal transition in both cell lines. SHH knockdown reduced IC(50) from 30.1 to 27.6 nM in Capan-1 while it strongly inhibited proli-feration in Panc-1 cells. Cells surviving high-dose gemcitabine treatment express increased levels of stem cell genes, show characteristics associated with epithelial-mesenchymal transition and retain their proliferative capacity.

Significance of combination therapy of zoledronic acid and gemcitabine on pancreatic cancer

In the present study, we examined the cytotoxic effects of combination therapy with zoledronic acid (ZOL) and gemcitabine (GEM) on pancreatic cancer cells in vitro and in vivo. Four human pancreatic cancer cell lines were treated with ZOL, GEM or a combination of both, and the effects of the respective drug regimens on cell proliferation, invasion and matrix metalloproteinase (MMP) expression were examined. A pancreatic cancer cell line was also intrasplenically or orthotopically implanted into athymic mice and the effects of these drugs on tumor metastasis and growth in vivo were evaluated by histological and immunohistochemical analyses. Combination treatment with low doses of ZOL and GEM efficiently inhibited the proliferation (P < 0.001) and invasion (P < 0.001) of pancreatic cancer cells in vitro. Western blotting assay revealed that MMP-2 and MMP-9 expression levels were decreased after ZOL treatment. In vivo, combined treatment significantly inhibited tumor growth (P < 0.05) and the development of liver metastasis (P < 0.05). These data revealed that ZOL and GEM, when used in combination, have significant antitumor, anti-metastatic and anti-angiogenic effects on pancreatic cancer cells. The present study is the first to report the significance of the combination treatment of ZOL and GEM in pancreatic cancer using an in vivo model. These data are promising for the future application of this drug regimen in patients with pancreatic cancer.

ZSTK474, a PI3K inhibitor, suppresses proliferation and sensitizes human pancreatic adenocarcinoma cells to gemcitabine

The phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway is important in cell proliferation and survival, and it is frequently and aberrantly activated in pancreatic adenocarcinoma. Potential anti-tumor effect(s) of ZSTK474, a PI3K/Akt inhibitor, together with a key clinically relevant anti-tumor agent, gemcitabine (GEM), have been reported in a human pancreatic cancer xenograft mouse model. However, the precise molecular mechanism of these anti-tumor effects has not been well elucidated. In this study, we investigated the molecular mechanism of GEM plus ZSTK474 in reducing tumor cell survival in human pancreatic cancer cell lines. Our study showed that ZSTK474 inhibited cell growth by arresting cells at the G1 phase and by inducing apoptosis. ZSTK474 also inhibited the phosphorylation of Akt, GSK3β and BAD. The combination of GEM and ZSTK474 demonstrated synergistic anti-tumor effects on pancreatic cancer cells in both transient (3 days) and long-term (14 days) clonogenic assays. Thus, we elucidated the potential molecular mechanism leading to the enhanced anti-tumor effect when GEM and ZSTK474 are combined in treatment.

Gemcitabine response in pancreatic adenocarcinoma cells is synergistically enhanced by dithiocarbamate derivatives

Pancreatic adenocarcinoma is a common malignancy that remains refractory to all available therapies, including the gold standard drug gemcitabine (GEM). We investigated the effect of the combination of GEM and each of the ionophore compounds pyrrolidine dithiocarbamate (PDTC) and disulfiram [DSF; 1-(diethylthiocarbamoyldisulfanyl)-N,N-diethylmethanethioamide] on p53(-/-) pancreatic adenocarcinoma cell growth. PDTC or DSF synergistically inhibited cell proliferation when used in combination with GEM by inducing apoptotic cell death. This effect was associated with an increased mitochondrial O(2)(•-) production and was further enhanced by zinc ions. Basal levels of mitochondrial O(2)(•-) or manganese superoxide dismutase (MnSOD) strictly correlated with the IC(50) for GEM or the percentage of synergism. Thus, the most relevant values of the antiproliferative synergism were obtained in GEM-resistant pancreatic adenocarcinoma cell lines. Interestingly, the GEM-sensitive T3M4 cells transfected with MnSOD expression vector showed mitochondrial O(2)(•-) and IC(50) for GEM similar to those of resistant cell lines. In vivo experiments performed on nude mice xenotransplanted with the GEM-resistant PaCa44 cell line showed that only the combined treatment with GEM and DSF/Zn completely inhibited the growth of the tumoral masses. These results and the consideration that DSF is already used in clinics strongly support the GEM and DSF/Zn combination as a new approach to overcoming pancreatic cancer resistance to standard chemotherapy.

Continuous and low-energy 125I seed irradiation changes DNA methyltransferases expression patterns and inhibits pancreatic cancer tumor growth

BACKGROUND

Iodine 125 (125I) seed irradiation is an effective treatment for unresectable pancreatic cancers. However, the radiobiological mechanisms underlying brachytherapy remain unclear. Therefore, we investigated the influence of continuous and low-energy 125I irradiation on apoptosis, expression of DNA methyltransferases (DNMTs) and cell growth in pancreatic cancers.

MATERIALS AND METHODS

For in vitro 125I seed irradiation, SW-1990 cells were divided into three groups: control (0 Gy), 2 Gy, and 4 Gy. To create an animal model of pancreatic cancer, the SW 1990 cells were surgically implanted into the mouse pancreas. At 10 d post-implantation, the 30 mice with pancreatic cancer underwent 125I seed implantation and were separated into three groups: 0 Gy, 2 Gy, and 4 Gy group. At 48 or 72 h after irradiation, apoptosis was detected by flow cytometry; changes in DNMTs mRNA and protein expression were assessed by real-time PCR and western blotting analysis, respectively. At 28 d after 125I seed implantation, in vivo apoptosis was evaluated with TUNEL staining, while DNMTs protein expression was detected with immunohistochemical staining. The tumor volume was measured 0 and 28 d after 125I seed implantation.

RESULTS

125I seed irradiation induced significant apoptosis, especially at 4 Gy. DNMT1 and DNMT3b mRNA and protein expression were substantially higher in the 2 Gy group than in the control group. Conversely, the 4 Gy cell group exhibited significantly decreased DNMT3b mRNA and protein expression relative to the control group. There were substantially more TUNEL positive in the 125I seed implantation treatment group than in the control group, especially at 4 Gy. The 4 Gy seed implantation group showed weaker staining for DNMT1 and DNMT3b protein relative to the control group. Consequently, 125I seed implantation inhibited cancer growth and reduced cancer volume.

CONCLUSION

125I seed implantation kills pancreatic cancer cells, especially at 4 Gy. 125I-induced apoptosis and changes in DNMT1 and DNMT3b expression suggest potential mechanisms underlying effective brachytherapy.

Molecular endoscopic ultrasound for diagnosis of pancreatic cancer

Endoscopic ultrasound-guided fine needle aspiration-biopsy is a safe and effective technique in diagnosing and staging of pancreatic ductal adenocarcinoma. However its predictive negative value does not exceed 50% to 60%. Unfortunately, the majority of pancreatic cancer patients have a metastatic and/or a locally advanced disease (i.e., not eligible for curative resection) which explains the limited access to pancreatic tissue specimens. Endoscopic ultrasound-guided fine needle aspiration-biopsy is the most widely used approach for cytological and histological material sampling in these situations used in up to two thirds of patients with pancreatic cancer. Based on this unique material, we and others developed strategies to improve the differential diagnosis between carcinoma and inflammatory pancreatic lesions by analysis of KRAS oncogene mutation, microRNA expression and methylation, as well as mRNA expression using both qRT-PCR and Low Density Array Taqman analysis. Indeed, differentiating pancreatic cancer from pseudotumoral chronic pancreatitis remains very difficult in current clinical practice, and endoscopic ultrasound-guided fine needle aspiration-biopsy analysis proved to be very helpful. In this review, we will compile the clinical and molecular advantages of using endoscopic ultrasound-guided fine needle aspiration-biopsy in managing pancreatic cancer.

Restoring sensitivity to oxaliplatin by a novel approach in gemcitabine-resistant pancreatic cancer cells in vitro and in vivo

Oxaliplatin (OxP) has been used in combination therapy with gemcitabine for the treatment of pancreatic cancer (PC), but the beneficial effect was marginal, which is believed to be due to de novo and acquired drug resistance of PC. Here, we report our in vitro and in vivo preclinical evidence in support of chemosensitization of drug-resistant cells by a nontoxic chemopreventive agent (genistein). Genistein pretreatment together with low concentration of OxP showed significant reduction in cell viability and colony formation concomitant with increased apoptosis (p < 0.01), which was highly synergistic. Drug resistance of PC is allegedly linked with both constitutive and OxP-induced activation of NF-κB, and we found that inactivation of (nuclear factor kappa B) NF-κB by genistein before treatment of cells with OxP was required for cell killing, which was consistent with the downregulation of NF-κB and its downstream antiapoptotic genes (Bcl-2, XIAPs and survivin). Most importantly, our in vivo experiments using orthotopic mouse model showed significant reduction in tumor size (p < 0.01) and reduction of locoregional lymph node metastasis by combination treatment. These results were also consistent with inactivation of NF-κB and the downregulation of NF-κB downstream genes, decreased proliferation marker (Ki-67) and increased apoptosis (TUNEL) in tumor remnants, all of which was consistent with in vitro findings. From these results, we conclude that genistein sensitizes drug-resistant PC to OxP, which is mechanistically linked with inactivation of NF-κB signaling, resulting in greater antitumor effects, and thus our data suggest that this approach could be useful in improving the treatment outcome for patients diagnosed with PC.

The role of radiotherapy in locally advanced pancreatic carcinoma

The prognosis for locally advanced pancreatic carcinoma remains dismal despite advances in chemotherapy and radiotherapy over the past few decades. The use of radiotherapy for pancreatic carcinoma is often disputed because of the hypothesis that patients with pancreatic cancer die from distant metastases. It is well accepted that the greatest chance for cure of pancreatic cancer involves surgical resection of the primary tumor. However, there is much controversy about the role of radiotherapy in local disease control. The aim of this Review is to discuss data from the available studies, both prospective and retrospective, that evaluate treatment options for locally advanced pancreatic cancer. We focus on the benefits associated with local therapies, including radiotherapy and surgical resection, as they relate to improved local disease control, prolonged overall survival and improved symptom control.

Folate-targeted supramolecular vesicular aggregates based on polyaspartyl-hydrazide copolymers for the selective delivery of antitumoral drugs

Supramolecular vesicular aggregates (SVAs) have the advantage of combining the safe and biocompatible properties of colloidal vesicular carriers based on phospholipids with those of polymeric materials, i.e. polyaspartyl-hydrazide (PAHy) copolymers. To provide SVAs with a certain tumour selectivity, folate moieties were chemically conjugated to PAHy copolymers. Physicochemical properties (mean sizes, polydispersity index and zeta potential) of folate-targeted SVAs (FT-SVAs) loaded with gemcitabine were evaluated. The antiproliferative and anticancer activity of gemcitabine-loaded FT-SVAs was evaluated against two cancer cell lines, i.e. MCF-7 cells which over-express the folate receptor and the BxPC-3 cells, which do not over-express this receptor. Gemcitabine-loaded FT-SVAs showed a significantly (p < 0.001) greater and more specific in vitro anticancer activity with respect to both the free drug and the drug-loaded conventional liposomes or untargeted SVAs. Confocal microscopy, flow cytometry analysis and beta-scintillation highlighted that FT-SVAs were able to interact with MCF-7 cells after just 3 h and to increase the amount internalization in cells over-expressing the folate receptor. The in vivo biodistribution and pharmacokinetic experiments showed that gemcitabine-loaded SVAs and FT-SVAs were removed from the circulatory system at a slower rate than the native drug and a prolonged gemcitabine plasma concentration was observed for up to 16 h. SVAs were accumulated mainly in the lungs, spleen and kidneys, while FT-SVAs were also up taken by brain. These interesting and stimulating results suggest the existence of a possible in vivo application of SVAs and encourage the use of folate as a targeting agent in anticancer therapy.

The experimental study for efficacy and safety of pancreatic cryosurgery

OBJECTIVE

This study was designed to basic information concerning the efficacy and safety of cryosurgery for pancreatic cancer. Fifteen healthy pigs were used to perform biochemical analysis and histological assessment.

METHODS

Following anesthesia and laparotomy, an argon-helium cryoprobe was inserted into the pancreas. The introduction of argon gas induced a rapid decrease in temperature to -160 degrees C (Group I, 5 pigs) or -110 degrees C (Group II, 5 pigs), respectively, resulting in ice-ball formation of 15-20mm diameter after 5 min. Following freezing, helium gas was circulated in the probe tip to increase the temperature to 10-20 degrees C over 3 min to thaw. The freeze/thaw cycle was then repeated. Group III (3 pigs) had a cryoprobe inserted, but without freezing, and Group IV (2 pigs) included untreated or normal control animals. Levels of serum amylase (AMY), IL-6 and C-RP were measured prior to freezing and for 7 days following the procedure. All pigs were euthanized 7 days post-treatment and pancreases were examined histologically.

RESULTS

Neither hyperaemia, edema or hemorrhage were observed in the un-frozen parts of the pancreas. Histological assessment revealed a significant level of necrosis in the central and lateral regions of the tissue frozen within the ice-ball. All cellular ultrastructure was destroyed and only observable as a few of remaining nuclei with broken crests and degranulated mitochondria and rough endoplasmic reticulum. There was a significant increase of serum AMY levels for a brief period in both "deep frozen" and the "shallow frozen" groups. However, the AMY also increased in two pigs in the "normal control" group and one pig from the "inserted cryoprobe without freeze" control group. All experimental pigs appeared healthy until the sacrifice time.

CONCLUSION

Cryosurgery is a safe and effective ablative procedure for pancreatic tissue resulting in minimal complications.

CD44-positive cells are responsible for gemcitabine resistance in pancreatic cancer cells

Accumulating evidence suggests that tumors are composed of a heterogeneous cell population with a small subset of cancer stem cells (CSCs) that sustain tumor formation and growth. Recently, there have been efforts to explain drug resistance of cancer cells based on the concept of CSCs having an intrinsic detoxifying mechanism. In the present study, to investigate the role of CSCs in acquiring chemoresistance in pancreatic cancer, gemcitabine-resistant cells were established by exposure to serially escalated doses of gemcitabine in HPAC and CFPAC-1 cells. Gemcitabine-resistant cells were more tumorigenic in vitro and in vivo, and had greater sphere-forming activity than parental cells. After high-dose gemcitabine treatment to eliminate most of the cells, CD44(+) cells proliferated and reconstituted the population of resistant cells. CD44(+)CD24(+)ESA(+) cells remained as a small subset in the resistant cell population. Among ATP-binding cassette (ABC) transporters, which are known as the mechanism of drug resistance in CSCs, ABCB1 (MDR1) was significantly augmented during the acquisition of drug resistance. ABC transporter inhibitor verapamil resensitized the resistant cells to gemcitabine in a dose-dependent manner and RNA interference of CD44 inhibited the clonogenic activity of resistant cells. In human pancreatic cancer samples, CD44 expression was correlated with histologic grade and the patients with CD44-positive tumors showed poor prognosis. These data indicate that cancer stem-like cells were expanded during the acquisition of gemcitabine resistance and in therapeutic application, targeted therapy against the CD44 or ABC transporter inhibitors could be applied to overcome drug resistance in the treatment of pancreatic cancer.

3,3'-Diindolylmethane enhances chemosensitivity of multiple chemotherapeutic agents in pancreatic cancer

Clinical management of pancreatic cancer is a major problem, which is in part due to both de novo and acquired resistance to conventional therapeutics. Here, we present in vitro and in vivo preclinical evidence in support of chemosensitization of pancreatic cancer cells by 3,3-diindolylmethane (DIM), a natural compound that can be easily obtained by consuming cruciferous vegetables. DIM pretreatment of pancreatic cancer cells led to a significantly increased apoptosis (P < 0.01) with suboptimal concentrations of chemotherapeutic agents (cisplatin, gemcitabine, and oxaliplatin) compared with monotherapy. It is known that resistance to chemotherapy in pancreatic cancer is associated with constitutively activated nuclear factor-kappaB (NF-kappaB), which becomes further activated by chemotherapeutic drugs. Our data provide mechanistic evidence for the first time showing that DIM potentiates the killing of pancreatic cancer cells by down-regulation of constitutive as well as drug-induced activation of NF-kappaB and its downstream genes (Bcl-xL, XIAP, cIAP, and survivin). Most importantly, using an orthotopic animal model, we found reduction in tumor size (P < 0.001) when DIM was given in combination with oxaliplatin compared with monotherapy. This was accompanied by loss of phospho-p65 and down-regulation of NF-kappaB activity and its downstream genes (Bcl-xL, survivin, and XIAP), which correlated with reduced cell proliferation (as assessed by Ki-67 immunostaining of tumor specimens) and evidence of apoptosis [as assessed by poly(ADP-ribose) polymerase cleavage and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining]. These results provide strong in vivo evidence in support of our hypothesis that DIM could abrogate chemotherapeutic drug (cisplatin, gemcitabine, and/or oxaliplatin)-induced activation of NF-kappaB, resulting in the chemosensitization of pancreatic tumors to conventional therapeutics.

Pilot study of irinotecan/oxalipltin (IROX) combination chemotherapy for patients with gemcitabine- and 5-fluorouracil- refractory pancreatic cancer

BACKGROUND

Gemcitabine- and 5-fluorouracil (5-FU)- based chemotherapy is a commonly used adjuvant or palliative treatment for patients with pancreatic cancer. However, a standard chemotherapy regimen has yet to be developed for patients refractory to gemcitabine and 5-FU treatment. We attempted to evaluate the efficacy and safety of a combination of irinotecan and oxaliplatin (IROX) as a salvage treatment for patients with gemcitabine- and 5-FU- refractory pancreatic cancer.

PATIENTS AND METHODS

Patients with advanced pancreatic cancer who were refractory to prior gemcitabine- and 5-FU- based chemotherapy were enrolled in this study. IROX chemotherapy was administered as follows: Irinotecan, 150 mg/m(2) on day 1; and oxaliplatin, 85 mg/m(2) on day 1 over 90 min every 2 weeks.

RESULT

From Mar. 2006 to Dec. 2008, a total of 14 patients were administered 50 cycles of chemotherapy. The male-to-female ratio of the patient group was 11:3. These patients ranged in age from 48 to 73 years (median 65.5 years old). 3 patients (21.4%) evidenced partial responses. four patients (28.6%) exhibited stable disease. The median time to progression and overall survival time were 1.4 (95% CI: 1.2-1.6) months and 4.1 (95% CI: 2.0-6.2) months, respectively. Major hematologic toxicities included grade 1-2 anemia (88%), neutropenia (36%), thrombocytopenia (30%), and grade 3-4 neutropenia (10%). The most frequently detected non-hematological toxicities were grade 3 diarrheas (14%).

CONCLUSION

The IROX regimen appears to constitute a feasible and tolerable salvage therapy in patients with advanced pancreatic cancer who have been previously treated with gemcitabine- and 5-FU-based chemotherapy.

Irinotecan monotherapy as second-line treatment in advanced pancreatic cancer

PURPOSE

The phase II study was conducted to evaluate the efficacy and safety of irinotecan as salvage single-agent chemotherapy in patients with advanced pancreatic cancer.

METHODS

Patients with measurable metastatic pancreatic cancer, progressive after previous gemcitabine-based chemotherapy were treated with irinotecan 150 mg/m(2) every 2 weeks. Treatment was repeated until disease progression or unacceptable toxicity.

RESULTS

Between March 2004 to February 2007, 33 patients were registered and treated with irinotecan monotherapy. The patients' median age was 59 years (range 36-70) and two had an ECOG performance status of 2. A total of 167 chemotherapy cycles were delivered (median, 4; range 2-12). In an intent-to-treat analysis, three (9%) confirmed partial response and 13 patients with stable disease were observed for a disease control rate of 48%. The median progression-free and overall survivals were 2.0 months (95% CI, 0.7-3.3) and 6.6 months (95% CI, 5.8-7.4), respectively. Toxic effects were mainly gastrointestinal (nausea in 64% of patients, diarrhea in 36%), Toxicity profiles were generally predictable and manageable, and there was no treatment-related death.

CONCLUSIONS

Second-line chemotherapy with single-agent irinotecan is marginally effective and well tolerated regimen for gemcitabine-pretreated patients with advanced pancreatic cancer.

Systemic 5-fluorouracil treatment causes a syndrome of delayed myelin destruction in the central nervous system

BACKGROUND

Cancer treatment with a variety of chemotherapeutic agents often is associated with delayed adverse neurological consequences. Despite their clinical importance, almost nothing is known about the basis for such effects. It is not even known whether the occurrence of delayed adverse effects requires exposure to multiple chemotherapeutic agents, the presence of both chemotherapeutic agents and the body's own response to cancer, prolonged damage to the blood-brain barrier, inflammation or other such changes. Nor are there any animal models that could enable the study of this important problem.

RESULTS

We found that clinically relevant concentrations of 5-fluorouracil (5-FU; a widely used chemotherapeutic agent) were toxic for both central nervous system (CNS) progenitor cells and non-dividing oligodendrocytes in vitro and in vivo. Short-term systemic administration of 5-FU caused both acute CNS damage and a syndrome of progressively worsening delayed damage to myelinated tracts of the CNS associated with altered transcriptional regulation in oligodendrocytes and extensive myelin pathology. Functional analysis also provided the first demonstration of delayed effects of chemotherapy on the latency of impulse conduction in the auditory system, offering the possibility of non-invasive analysis of myelin damage associated with cancer treatment.

CONCLUSIONS

Our studies demonstrate that systemic treatment with a single chemotherapeutic agent, 5-FU, is sufficient to cause a syndrome of delayed CNS damage and provide the first animal model of delayed damage to white-matter tracts of individuals treated with systemic chemotherapy. Unlike that caused by local irradiation, the degeneration caused by 5-FU treatment did not correlate with either chronic inflammation or extensive vascular damage and appears to represent a new class of delayed degenerative damage in the CNS.

A pilot study on combination of cryosurgery and 125iodine seed implantation for treatment of locally advanced pancreatic cancer

AIM: To study the therapeutic value of combination of cryosurgery and ¹²⁵iodine seed implantation for locally advanced pancreatic cancer.

METHODS: Forty-nine patients with locally advanced pancreatic cancer (males 36, females 13), with a median age of 59 years, were enrolled in the study. Twelve patients had liver metastases. In all cases the tumors were considered unresectable after a comprehensive evaluation. Patients were treated with cryosurgery, which was performed intraoperatively or percutaneously under guidance of ultrasound and/or computed tomography (CT), and ¹²⁵iodine seed implantation, which was performed during cryosurgery or post-cryosurgery under guidance of ultrasound and/or CT. A few patients received regional celiac artery chemotherapy.

RESULTS: Thirteen patients received intraoperative cryosurgery and 36 received percutaneous cryosurgery. Some patients underwent repeat cryosurgery. ¹²⁵Iodine seed implantation was performed during freezing procedure in 35 patients and 3-9 d after cryosurgery in 14 cases. Twenty patients, 10 of whom had hepatic metastases received regional chemotherapy. At 3 mo after therapy, CT was repeated to estimate tumor response to therapy. Most patients showed varying degrees of tumor necrosis. Complete response (CR) of tumor was seen in 20.4% patients, partial response (PR), in 38.8%, stable disease (SD), in 30.6%, and progressive disease (PD), in 10.2%. Adverse effects associated with cryosurgery included upper abdomen pain and increased serum amylase. Acute pancreatitis was seen in 6 patients one of whom developed severe pancreatitis. All adverse effects were controlled by medical management with no poor outcome. There was no therapy-related mortality. During a median follow-up of 18 mo (range of 5-40), the median survival was 16.2 mo, with 26 patients (53.1%) surviving for 12 mo or more. Overall, the 6-, 12-, 24- and 36-mo survival rates were 94.9%, 63.1%, 22.8% and 9.5%, respectively. Eight patients had survival of 24 mo or more. The patient with the longest survival (40 mo) is still living without evidence of tumor recurrence.

CONCLUSION: Cryosurgery, which is far less invasive than conventional pancreatic resection, and is associated with a low rate of adverse effects, should be the treatment of choice for patients with locally advanced pancreatic cancer. ¹²⁵Iodine seed implantation can destroy the residual surviving cancer cells after cryosurgery. Hence, a combination of both modalities has a complementary effect.

Cryosurgery with combination of (125)iodine seed implantation for the treatment of locally advanced pancreatic cancer

OBJECTIVE

To study the therapeutic value of cryosurgery with combination of (125)iodine seed implantation for locally advanced pancreatic cancer.

METHODS

Thirty-eight patients with locally advanced pancreatic cancer were enrolled in this study. The diagnosis was confirmed by pathology in 31 patients. Ten patients had metastases of the peripancreatic lymph node and eight had liver metastases. The therapy included cryosurgery, which was performed intra-operatively or percutaneously under guidance of ultrasound and/or computed tomography (CT), and (125)iodine seed implantation, which was performed during cryosurgery process or post-cryosurgery under the guidance of ultrasound and/or CT.

RESULTS

Eleven patients received intra-operative cryosurgery and 27 received percutaneous cryosurgery. Fourteen patients underwent two procedures of cryosurgery and three underwent three procedures of cryosurgery. (125)Iodine seed implantation was performed during the freezing procedure in 29 patients and within 3-7 days after cryosurgery in nine patients under ultrasound and CT guidance. Fifteen patients, of whom 13 had metastases of peripancreatic lymph nodes or liver received regional chemotherapy. At 3 months after therapy, a CT follow-up was performed to estimate the tumor response to therapy. Most of the patients had varying degrees of tumor necrosis. A complete response of the tumor was seen in 23.6% of patients, a partial response in 42.1%, stable disease in 26.3% and progressive disease in 7.9%. The adverse effects associated with cryosurgery mainly included pain of the upper abdomen and increased serum amylase activity. Acute pancreatitis was seen in five patients, one of whom presented a severe type of pancreatitis. During the followed-up of a median of 16 months (range of 5-37) median overall survival was 12 months, 19 patients (50.0%) survived for 12 months or longer and four survived for 24 months or longer.

CONCLUSION

As it is far less invasive than conventional pancreas resection and entails a low rate of adverse effects, cryosurgery should be the choice modality for most patients with locally advanced pancreatic cancer. (125)Iodine seed implantation can destroy residue survival cancer cells after cryosurgery. Hence, combination of both modalities has a complementary effect.

5-lipoxygenase suppresses TNF-α-induced apoptosis in pancreatic tumor cell lines

AIM: To investigate the effects of 5-lipoxygenase and LTB4 on the proliferation and apoptosis of pancreatic cancer cells in vitro.

METHODS: The human pancreatic cancer cell lines ASPC-1, PANC-1 and SW1990 were cultured and the levels of 5-LOX and the supernatant product LTB4 were examined by Western blot and ELISA. TNF-α-induced cell apoptosis was analyzed by annexin V/PI double staining with flow cytometry. 5-LOX cDNA stably transfected SW1990 cell lines were established and treated with TNF-α. Their sensitivity to apoptosis induction was examined.

RESULTS: The pancreatic cell lines tested in this study all expressed substitute levels of 5-LOX and LTB4. The percentages of apoptotic wild-type SW1990 cells were 25.4% ± 3.65% and 43.5% ± 5.23% after 12 h and 24 h treatment with 20 μg/L TNF-α, respectively. However, these effects were significantly decreased (P < 0.01) in 5-LOX over-expressing cells. The percentages of these cells undergoing apoptosis were 13.2% ± 2.01% and 21.7% ± 3.65% after 12 h and 24 h treatment, respectively. Furthermore, the addition of exogenous LTB4 (10 nmol/L) significantly suppressed the percentage of wild-type cells undergoing apoptosis from 47.6% ± 5.32% to 18.5% ± 5.69%. Blocking LTB4 signals with specific receptor antagonists reversed the sensitivity of 5-LOX transfected cells to apoptosis.

CONCLUSION: High levels of expression of 5-LOX and LTB4 make pancreatic cell lines more resistant to TNF-α-induced apoptosis, suggesting that the 5-LOX pathway plays an important role in the pathogenesis of pancreatic cancer.