Advances in the treatment of pancreatic cancer: limitations of surgery and evaluation of new therapeutic strategies

Changes in Skeletal Muscle Volume During Preoperative Chemotherapy Affect the Outcome of Pancreatic Cancer

BACKGROUND

This study aimed to investigate the effects of changes in clinicopathological factors during preoperative chemotherapy for pancreatic cancer, including skeletal muscle volume, on recurrence and prognosis after pancreatectomy.

METHODS

Data from 41 patients who underwent resection for pancreatic cancer after preoperative chemotherapy from 2012 to 2021 were retrospectively reviewed. Skeletal muscle volume was substituted for the psoas muscle area (PMA) at the level of the third lumbar vertebra. We investigated the relationship of clinicopathological factors during preoperative chemotherapy with disease-free survival (DFS) and overall survival (OS). The association between clinicopathological factors and a decrease in PMA was investigated.

RESULTS

In the multivariate analyses for DFS and OS, the factors associated with recurrence were as follows: decrease in PMA (P = 0.003) and the absence of adjuvant therapy (P = 0.03), and the factors associated with poor prognosis were as follows: decrease in PMA (P = 0.04) and the absence of adjuvant therapy (P = 0.008), and the resectability of borderline resectable and unresectable-locally advanced tumors (P = 0.033). All patients with partial response according to the Response Evaluation Criteria in Solid Tumors (version 1.1) had no decrease in PMA (P = 0.01). The proportion of patients with Evans classification ≥ II was significantly higher in the group without a decrease in PMA (P = 0.02). The proportion of patients with an average relative dose intensity of adjuvant therapy ≥0.6 was significantly higher in the group without a decrease in PMA (P = 0.02).

CONCLUSION

Changes in preoperative skeletal muscle volume during preoperative chemotherapy for pancreatic cancer is a potential predictor of recurrence and prognosis after pancreatectomy.

Advances in Immunotherapeutics in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) accounts for up to 95% of all pancreatic cancer cases and is the seventh-leading cause of cancer death. Poor prognosis is a result of late presentation, a lack of screening tests and the fact some patients develop resistance to chemotherapy and radiotherapy. Novel therapies like immunotherapeutics have been of recent interest in pancreatic cancer. However, this field remains in its infancy with much to unravel. Immunotherapy and other targeted therapies have yet to yield significant progress in treating PDAC, primarily due to our limited understanding of the disease immune mechanisms and its intricate interactions with the tumour microenvironment (TME). In this review we provide an overview of current novel immunotherapies which have been studied in the field of pancreatic cancer. We discuss their mechanisms, evidence available in pancreatic cancer as well as the limitations of such therapies. We showcase the potential role of combining novel therapies in PDAC, postulate their potential clinical implications and the hurdles associated with their use in PDAC. Therapies discussed with include programmed death checkpoint inhibitors, Cytotoxic T-lymphocyte-associated protein 4, Chimeric Antigen Receptor-T cell therapy, oncolytic viral therapy and vaccine therapies including KRAS vaccines, Telomerase vaccines, Gastrin Vaccines, Survivin-targeting vaccines, Heat-shock protein (HSP) peptide complex-based vaccines, MUC-1 targeting vaccines, Listeria based vaccines and Dendritic cell-based vaccines.

Clinical Translation and Evaluation of a Handheld and Biocompatible Mass Spectrometry Probe for Surgical Use

BACKGROUND

Intraoperative tissue analysis and identification are critical to guide surgical procedures and improve patient outcomes. Here, we describe the clinical translation and evaluation of the MasSpec Pen technology for molecular analysis of in vivo and freshly excised tissues in the operating room (OR).

METHODS

An Orbitrap mass spectrometer equipped with a MasSpec Pen interface was installed in an OR. A "dual-path" MasSpec Pen interface was designed and programmed for the clinical studies with 2 parallel systems that facilitated the operation of the MasSpec Pen. The MasSpec Pen devices were autoclaved before each surgical procedure and were used by surgeons and surgical staff during 100 surgeries over a 12-month period.

RESULTS

Detection of mass spectral profiles from 715 in vivo and ex vivo analyses performed on thyroid, parathyroid, lymph node, breast, pancreatic, and bile duct tissues during parathyroidectomies, thyroidectomies, breast, and pancreatic neoplasia surgeries was achieved. The MasSpec Pen enabled gentle extraction and sensitive detection of various molecular species including small metabolites and lipids using a droplet of sterile water without causing apparent tissue damage. Notably, effective molecular analysis was achieved while no limitations to sequential histologic tissue analysis were identified and no device-related complications were reported for any of the patients.

CONCLUSIONS

This study shows that the MasSpec Pen system can be successfully incorporated into the OR, allowing direct detection of rich molecular profiles from tissues with a seconds-long turnaround time that could be used to inform surgical and clinical decisions without disrupting tissue analysis workflows.

Combination of a novel microtubule inhibitor MBRI-001 and gemcitabine synergistically induces cell apoptosis by increasing DNA damage in pancreatic cancer cell lines

Pancreatic cancer (PC) is a highly malignant cancer with poor prognosis. Although gemcitabine (GEM; 2',2'-difluoro-deoxycytidine) has been used as the first-line chemotherapeutic agent in PC treatment for decades, its limited efficacy remains a significant clinical issue, which may be resolved by GEM combination therapy. In this study, we aimed to investigate the anti-tumor effects of MBRI-001 in combination with GEM in BxPC-3 and MIA PaCa-2 human PC cell lines. In vitro and in vivo results indicate that MBRI-001 showed synergistic activity with GEM. GEM induced apoptosis by increasing DNA damage (phosphorylated core histone protein H2AX (γ-H2AX)), MBRI-001 activated mitochondrial-apoptotic pathway (cleaved poly-ADP ribose polymerase (PARP)). Thus, the combination of the two intensified both apoptosis and DNA damage and showed significantly superior anti-tumor activity compared to each agent alone. The adoption of combination of MBRI-001 with GEM may be beneficial as they act synergistically and thus, can be a potential therapeutic choice for improving the prognosis of PC patients in the future.

The LIM protein Ajuba/SP1 complex forms a feed forward loop to induce SP1 target genes and promote pancreatic cancer cell proliferation

BACKGROUND

The aim of this study is to explore the molecular mechanism of the LIM protein Ajuba and the transcription factor SP1 in the pathogenesis and progression of PDAC. Ajuba is a newly defined transcriptional co-regulator and plays important role in various cancer development, while SP1 is a classic transcription factor, and is closely related with a variety of gene expression and cancer development including PDAC.

METHODS

The expression of Ajuba and SP1 in PDAC tissues was detected by immunohistochemistry (IHC), and the correlation between expression level and clinical prognosis of Ajuba and SP1 was extensively analyzed using online tools. The interaction between Ajuba and SP1 was examined by co-immunoprecipitation (co-IP) and GST-pulldown assays. Stable cell lines were established via lentiviral infection, and was examined by qRT-PCR and western blot assays. The effects of Ajuba/SP1 on PDAC cell proliferation were examined using CCK8 and colony formation assays. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were employed to examine the transcription activity.

RESULTS

The expression level (protein and mRNA) of Ajuba and SP1 was elevated in PDAC tissues and was positively correlated; patients with high Ajuba and SP1 expression had a poor prognosis. Mechanistically, Ajuba binds to the C-terminus of SP1 and functions as a co-activator to enhance SP1 gene expression and promote cell proliferation; the promoter of Ajuba contains functional SP1 responsive elements and Ajuba itself is a target gene of SP1.

CONCLUSION

Ajuba functions as a co-activator of SP1 to induce its target gene, and that Ajuba itself is a target genes of SP1. Ajuba/SP1 complex could form a feed forward loop to drive SP1 target gene transcription and promote cell proliferation of pancreatic cancer cells. Ajuba and SP1 might be biomarkers for PDAC diagnostics, prognosis and targets for new therapeutics.

FH535, a β-catenin pathway inhibitor, represses pancreatic cancer xenograft growth and angiogenesis

The WNT/β-catenin pathway plays an important role in pancreatic cancer carcinogenesis. We evaluated the correlation between aberrant β-catenin pathway activation and the prognosis pancreatic cancer, and the potential of applying the β-catenin pathway inhibitor FH535 to pancreatic cancer treatment. Meta-analysis and immunohistochemistry showed that abnormal β-catenin pathway activation was associated with unfavorable outcome. FH535 repressed pancreatic cancer xenograft growth in vivo. Gene Ontology (GO) analysis of microarray data indicated that target genes responding to FH535 participated in stemness maintenance. Real-time PCR and flow cytometry confirmed that FH535 downregulated CD24 and CD44, pancreatic cancer stem cell (CSC) markers, suggesting FH535 impairs pancreatic CSC stemness. GO analysis of β-catenin chromatin immunoprecipitation sequencing data identified angiogenesis-related gene regulation. Immunohistochemistry showed that higher microvessel density correlated with elevated nuclear β-catenin expression and unfavorable outcome. FH535 repressed the secretion of the proangiogenic cytokines vascular endothelial growth factor (VEGF), interleukin (IL)-6, IL-8, and tumor necrosis factor-α, and also inhibited angiogenesis in vitro and in vivo. Protein and mRNA microarrays revealed that FH535 downregulated the proangiogenic genes ANGPT2, VEGFR3, IFN-γ, PLAUR, THPO, TIMP1, and VEGF. FH535 not only represses pancreatic CSC stemness in vitro, but also remodels the tumor microenvironment by repressing angiogenesis, warranting further clinical investigation.

Orphan nuclear receptor Nurr1 as a potential novel marker for progression in human pancreatic ductal adenocarcinoma

Nuclear receptor related-1 protein (Nurr1) is a novel orphan member of the nuclear receptor superfamily (the NR4A family) involved in tumorigenesis. The aim of the present study was to investigate the expression and possible function of Nurr1 in pancreatic ductal adenocarcinoma (PDAC). The expression pattern of Nurr1 protein was determined using immunohistochemical staining in 138 patients with PDAC. Elevated Nurr1 expression was more commonly observed in PDAC tissues and cell lines compared with healthy controls. Elevated expression was significantly associated with histological differentiation (P=0.041), lymph node metastasis (P=0.021), TNM classification of malignant tumors stage (P=0.031) and poor survival (P=0.001). Further experiments demonstrated that suppression of endogenous Nurr1 expression attenuated cell proliferation, migration and invasion, and induced apoptosis of PDAC cells. In conclusion, these results suggest that Nurr1 has an important role in the progression of PDAC and may be used as a novel marker for therapeutic targets.

Oridonin inhibition and miR‑200b‑3p/ZEB1 axis in human pancreatic cancer

The relationship among oridonin, miR-200b-3p and pancreatic cancer on epithelial-to-mesenchymal transition (EMT) was investigated for the molecular mechanism or signaling pathways on the migration in pancreatic cancer. BxPC-3 and PANC-1 cells were cultivated and the IC50 of oridonin in BxPC-3 and PANC-1 cells were obtained by the CCK-8 array. The expression of miR‑200b-3p was verified by using real-time PCR and its target gene was predicted. BxPC-3 and PANC-1 cells were treated with oridonin or transfected by miR-200b-3p, those cells were used for western blot assay, Transwell assay, ELISA, immunofluorescence staining, tumorigenesis assay in nude mice and immunohistochemical assay to verify the effects of oridonin or miR-200b-3p on pancreatic cancer. We found that oridonin inhibited the proliferation of BxPC-3 and PANC-1 cells in a dose-dependent manner. miR-200b-3p was downregulated by oridonin in BxPC-3 and PANC-1 cells. ZEB1 was a target gene for miR-200b-3p. Oridonin or overexpression of miR‑200b-3p can inhibit the cell migration in BxPC-3 and PANC-1 cells. miR-200b-3p can inhibit the EMT and oridonin can inhibit the expression of ZEB1, N-cadherin and fibronectin but not increase the expression of E-cadherin, while the cell adhesion molecules ICAM-1 and VCAM-1 were decreased by oridonin in BxPC-3 and PANC-1 cells and the cytoskeleton was altered by oridonin in PANC-1 cells compared with the control. In summary, the results demonstrate that miR‑200b-3p was able to inhibit the EMT of human pancreatic cancer in vivo and in vitro by targeted ZEB1. In vitro, oridonin had a certain effect on the migration in BxPC-3 and PANC-1 cells, but not though type III EMT by miR-200-3p/ZEB1 axis, and may be related to type Ⅱ EMT, tumor microenvironment or altering the cytoskeleton. In vivo, oridonin inhibited the cancer migration in the nude mouse model though inhibiting EMT.

Progress in treatment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a malignant tumor of the digestive system with a high degree of malignancy, accounting for about 90% of cases of pancreatic cancer. It has an occult onset and progresses rapidly, with a poor treatment effect and prognosis. It is one of malignant tumors with the worst prognosis. Surgical resection, as the only effective treatment, can be performed in only 20%-30% of patients, and the average period of survival after surgery is still less than 2 years. The main treatment strategy for PDAC are surgery-based individualized treatment modalities under comprehensive multidisciplinary collaboration. Currently, the therapeutic effect on pancreatic cancer is still not satisfactory. In recent years, various treatments for PDAC is becoming a hot spot of research. This article reviews the progress in the treatment of PDAC in terms of radical surgery, palliative surgery, adjuvant therapy, and other treatment opinions.

No-touch isolation techniques for pancreatic cancer

The rate of recurrence, including liver metastasis is high in pancreatic cancer, even when complete surgical resection is performed as a curative treatment. In patients with pancreatic cancer, the handling and grasping of the pancreas during surgery may increase the risk of liver metastasis, as squeezing may spread cancer cells via the portal vein. A no-touch isolation technique might prevent the spread of cancer cells via the hematogenous metastatic route in patients with pancreatic cancer. However, while no-touch isolation techniques are simple, feasible and, in theory, ideal procedures for the surgical treatment of pancreatic cancer, there have been no randomized controlled prospective studies to validate their advantages and their efficacy remains controversial. It is, therefore, worth investigating the use of no-touch isolation techniques in pancreatic cancer.

Pancreatic cancer in the USA: persistence of undertreatment and poor outcome

PURPOSE

Despite decades of research, consensus on optimal treatment for pancreatic cancer has not been reached and survival remains bleak. This study aimed to evaluate predictors of treatment and survival among patients treated in community settings.

METHODS

A sample of pancreatic cancer patients who were diagnosed in 2009 and reported to the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) program (n = 977) was included. Logistic regression was used to assess factors associated with therapy modality. Survival was examined using the Kaplan-Meier method and Cox proportional hazards regression. All analyses were conducted stratified by tumor stage.

RESULTS

Among stages I-II patients, 27 % received no treatment and only 47 % received surgery. Among these patients, no treatment was associated with older age, being a woman, not being married, lower income, and larger or unknown tumor size. Additionally, the type of adjuvant therapy received varied by tumor characteristics, race/ethnicity, and socioeconomic status. The most common therapies for stage III tumors were chemoradiation (40.8 %) and chemotherapy (21.9 %) alone. Half of stage IV patients received chemotherapy; chemotherapy was less common in patients who were older, in a minority race/ethnicity, and not married. Although treatment was associated with better prognosis, even among stages I-II patients who underwent surgery, a quarter succumbed to their disease within 17 months.

CONCLUSION

A significant proportion of pancreatic cancer patients remain undertreated primarily due to nonclinical factors, including marital status. Further investigating what aspects of marriage are contributing to this association will provide a better understanding of pancreatic cancer treatment barriers.

Susceptibility of pancreatic cancer stem cells to reprogramming

Previous reports have indicated that reprogramming technologies may be useful for altering the malignant phenotype of cancer cells. Although somatic stem cells in normal tissues are more sensitive to reprogramming induction than differentiated cells, it remains to be elucidated whether any specific subpopulations are sensitive to reprogramming in heterogeneous tumor tissues. Here we examined the susceptibility of pancreatic cancer stem cells (CSC) and non-CSC to reprogramming. To characterize CSC populations, we focused on c-Met signaling, which has been identified as a marker of CSC in mouse experiments in vivo. Cells that expressed high levels of c-Met showed higher CSC properties, such as tumor-initiating capacity, and resistance to gemcitabine. Real-time reverse transcription-polymerase chain reaction in cells expressing high levels of c-Met revealed endogenous expression of reprogramming factors, such as OCT3/4, SOX2, KLF4 and cMYC. Introduction of these four factors resulted in higher alkaline phosphatase staining in cells with high c-Met expression than in controls. Therefore, the study results demonstrate that cellular reprogramming may be useful for extensive epigenetic modification of malignant features of pancreatic CSC.

Oridonin inhibits BxPC-3 cell growth through cell apoptosis

Oridonin, an ent-kaurene diterpenoid extracted from the traditional Chinese herb Rabdosia rubescens, has multiple biological and pharmaceutical functions and has been used clinically for many years. While the antitumor function of oridonin has been corroborated by numerous lines of evidence, its anticancer mechanism has not been well documented. In this study, the pancreatic cancer cell line BxPC-3 was used as a model to investigate a possible anticancer mechanism of oridonin through examining its effects on cell viability. The results showed that oridonin affected cell viability in a time- and dose-dependent manner. After exposure to different oridonin concentrations, growth rates and cell cycle arrest of BxPC-3 cells were significantly reduced compared with untreated cells, suggesting its effects on proliferation inhibition. Detailed signaling pathway analysis by western blot analysis revealed that low-dose oridonin treatment inhibited BxPC-3 cell proliferation by up-regulating p53 and down-regulating cyclin-dependent kinase 1 (CDK1), which led to cell cycle arrest in the G2/M phase. A high-dose oridonin not only arrested BxPC-3 cells in the G2/M phase but also induced cell accumulation in the S phase, presumably through γH2AX up-regulation and DNA damage. In addition, our results showed that a cell subpopulation was stained with propidium iodide after oridonin treatment. Protein quantification showed that cleaved poly(ADP-ribose) polymerase (PARP) expression was increased after a high-dose oridonin treatment, especially after long-term exposure. Accompanied by the increased level of deactivated PARP in BxPC-3 cells, the apoptosis initiators caspase-3 and caspase-7 expressions were also significantly increased, suggesting that caspase-mediated apoptosis contributed to cell death.

Long-term survival following total pancreatectomy and superior mesenteric-portal vein resection for pancreatic ductal adenocarcinoma: A case report

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with few therapeutic options. At present, surgical resection remains the only potential curative treatment for PDAC. However, only 15–20% of patients with PDAC are eligible for lesion resection. Total pancreatectomy (TP) and superior mesenteric-portal vein resection (SMPVR) may increase the rate of resection of PDCA, but the effect of this approach on improving long-term patient outcomes remains controversial. The present study investigated a case of PDAC in the pancreatic neck of a male patient. The patient underwent a TP, combined with SMPVR, for a margin-negative resection. Following an uneventful post-operative recovery, the patient received adjuvant chemoradiotherapy. The patient is currently alive at six years post-surgery, with a high quality of life. Given the clinical outcome of this patient, TP combined with SMPVR may provide PDAC patients with an opportunity for long-term survival. Therefore, patients with PDAC that is believed to be unresectable based on pre-operative assessment, may benefit from TP and SMPVR.

A novel long non-coding RNA ENST00000480739 suppresses tumour cell invasion by regulating OS-9 and HIF-1α in pancreatic ductal adenocarcinoma

BACKGROUND

Invasion and metastasis are the distinct biologic characteristics of cancer, resulting in an exceptionally low 5-year survival rate in pancreatic ductal adenocarcinoma (PDAC). Understanding in detail the mechanisms underlying PDAC metastasis is critical for prevention and effective interventions. Long non-coding RNAs (lncRNAs) have been documented as having a critical role in cancer development and progression.

METHODS

We examined the expression levels of lncRNA ENST00000480739 and osteosarcoma amplified-9 (OS-9) mRNA in a cohort of 35 PDAC patients. Cell proliferation, invasion and migration were examined with and without ENST00000480739 overexpression in PDAC cells.

RESULTS

We determined that the ENST00000480739 expression level was remarkably decreased in tumorous tissues compared with their corresponding non-tumorous tissues. The expression of ENST00000480739 was negatively associated with tumour node metastasis stage and lymph node metastasis. In addition, ENST0000048073 was an independent prognostic factor of survival time in PDAC patients following surgery. Besides, enforced expression of ENST00000480739 suppressed PDAC cells' invasion in vitro. Overexpression of ENST00000480739 significantly increased both mRNA and protein levels of OS-9, and the luciferase assays confirmed that ENST00000480739 positively regulates OS-9 by activating the transcription level of the OS-9 promoter. We further found that ENST00000480739 may target hypoxia-inducible factor-1α (HIF-1α) expression by upregulating OS-9.

CONCLUSIONS

These findings suggest that the frequently downregulated ENST00000480739 in PDAC contributes to tumour metastasis and progression by regulating HIF-1α. Long non-coding RNA ENST00000480739 may provide not only a therapeutic potential to suppress metastasis but it may also be a novel biomarker for risk prognostication and personal therapy screening of PDAC patients.

Long non-coding RNAs expressed in pancreatic ductal adenocarcinoma and lncRNA BC008363 an independent prognostic factor in PDAC

BACKGROUND

Long non-coding RNAs (lncRNAs) are a novel class of mRNA-like transcripts with no protein coding capacity, but with a variety of functions including roles in epigenetics and gene regulation. In recent reports, the aberrant expression of lncRNAs has been associated with human cancers, suggesting a critical role in tumorigenesis.

METHOD

In the present study, we analyzed mRNA and lncRNA expression in pancreatic ductal adenocarcinoma (PDAC) by microarray platform, and analyzed lncRNA expression from 30 patients who underwent pancreatectomy for pancreatic ductal adenocarcinoma by real-time PCR. We also investigated the relationship between the expression of BC008363 and the prognosis of PDAC patients by Kaplan-Meier analyses.

RESULTS

Based on the microarray data, 1881 lncRNAs were upregulated and 3369 lncRNAs were downregulated (fold change ≥4.0 or ≤0.4, p < 0.01) in the PDAC group compared with the control group. We found that the expression level of lncRNA BC008363 was significantly lower (23-fold) in PDAC tissues compared to corresponding nontumor pancreatic tissues, and patients with high levels of lncRNA BC008363 expression had significantly better survival rates than those with low levels of lncRNA BC008363 expression.

CONCLUSIONS

These data indicate that there are different lncRNAs expressed in pancreatic cancer biology and that lncRNA BC008363 may be a novel biomarker for the prognosis of pancreatic cancer.

Computational analyses reveal a prognostic impact of TULP3 as a transcriptional master regulator in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is recognized world-wide as an aggressive disease with poor prognosis in patients with or without resection. Further knowledge about the biological mechanisms of PDAC is necessary to enable the identification of novel molecular markers and therapeutic targets for early diagnosis and improved treatment. Transcription factors are the final effectors of signaling pathways and regulate a number of cellular functions. Changes in their expression may contribute to cellular transformation and tumor progression. Thus, the aim of the present study was to identify the Master Regulators (MRs) of transcription potentially involved in PDAC disease. To achieve this goal, we utilized microarray data to correlate MR genes with the tumor phenotype. Analyses were performed with RTN, Limma, and Survival packages in the R environment. We identified Tubby-like protein 3 (TULP3) as a MR of transcription in PDAC samples. The prognostic value of TULP3 was assessed in three independent cohort analyses. Our data demonstrated that pancreatic cancer patients exhibiting high transcriptional levels of TULP3 showed a poor overall survival rate. High expression levels of TULP3 may play an essential role in pancreatic cancer progression and possibly lead to a poor clinical outcome. Our results highlight the potential use of TULP3 as a clinical prognostic biomarker for pancreatic adenocarcinoma.

FOXM1 and its oncogenic signaling in pancreatic cancer pathogenesis

Pancreatic cancer is a devastating disease with an overall 5-year survival rate less than 5%. Multiple signaling pathways are implicated in the pathogenesis of pancreatic cancer, such as Wnt/β-catenin, Notch, Hedgehog, hypoxia-inducible factor, signal transducer and activator of transcription, specificity proteins/Krüppel-like factors, and Forkhead box (FOX). Recently, increasing evidence has demonstrated that the transcription factor FOXM1 plays important roles in the initiation, progression, and metastasis of a variety of human tumors, including pancreatic cancer. In this review, we focus on the current understanding of the molecular pathogenesis of pancreatic cancer with a special focus on the function and regulation of FOXM1 and rationale for FOXM1 as a novel molecular target for pancreatic cancer prevention and treatment.

Proteome variations in pancreatic stellate cells upon stimulation with proinflammatory factors

Pancreatic stellate cells are key mediators in chronic pancreatitis and play a central role in the development of pancreatic fibrosis, stromal formation, and progression of pancreatic cancer. This study was aimed at investigating molecular changes at the level of the proteome that are associated with the activation of pancreatic stellate cells by proinflammatory factors, namely TNF-α, FGF2, IL6, and chemokine (C-C motif) ligand 4 (CCL4). They were added individually to cells growing in serum-free medium next to controls in medium supplemented with serum, thus containing a mixture of them all, or in serum-free medium alone. Variations were detected by means of a microarray of 810 antibodies targeting relevant proteins. All tested factors triggered increased proliferation and migration. Further analysis showed that TNF-α is the prime factor responsible for the activation of pancreatic stellate cells. CCL4 is associated with cellular neovascularization, whereas FGF2 and IL6 induction led to better cellular survival and decreased apoptotic activity of the stellate cells. The identified direct effects of individual cytokines on human pancreatic stellate cells provide new insights about their contribution to pancreatic cancer promotion.

Proteome variations in pancreatic stellate cells upon stimulation with proinflammatory factors

Pancreatic stellate cells are key mediators in chronic pancreatitis and play a central role in the development of pancreatic fibrosis, stromal formation, and progression of pancreatic cancer. This study was aimed at investigating molecular changes at the level of the proteome that are associated with the activation of pancreatic stellate cells by proinflammatory factors, namely TNF-α, FGF2, IL6, and chemokine (C-C motif) ligand 4 (CCL4). They were added individually to cells growing in serum-free medium next to controls in medium supplemented with serum, thus containing a mixture of them all, or in serum-free medium alone. Variations were detected by means of a microarray of 810 antibodies targeting relevant proteins. All tested factors triggered increased proliferation and migration. Further analysis showed that TNF-α is the prime factor responsible for the activation of pancreatic stellate cells. CCL4 is associated with cellular neovascularization, whereas FGF2 and IL6 induction led to better cellular survival and decreased apoptotic activity of the stellate cells. The identified direct effects of individual cytokines on human pancreatic stellate cells provide new insights about their contribution to pancreatic cancer promotion.

Inhibition of SIRT1 combined with gemcitabine therapy for pancreatic carcinoma

BACKGROUND

Pancreatic carcinoma possesses one of the highest lethality rates, highest drug-resistance, and highest incidence rates. The objective of this research was to enhance the efficacy and drug-resistance for pancreatic carcinoma by using inhibition of SIRT1 combined with gemcitabine therapy methods.

METHODS

Three pancreatic carcinoma cells (PANC-1 cells, BxPC-3 cells, and SW1990 cells) received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vitro; then BxPC-3 pancreatic cancer xenogeneic mice also received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vivo.

RESULTS

The cleaved poly ADP ribose polymerase (PARP)-1 effect of drug in pancreatic carcinoma cells was significantly different (P < 0.05) and the efficacy in descending order was the combination therapy with inhibition of SIRT1 and gemcitabine, inhibition of SIRT1, and gemcitabine. The BxPC-3 pancreatic cancer xenogeneic mice model received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vivo and the results showed that the tumor volumes decreased and the survival rate within 45 days increased according to the order of the given drugs and the difference was significant (P < 0.05).

CONCLUSION

Combination therapy with inhibition of SIRT1 and gemcitabine could improve efficacy and survival time in a BxPC-3 pancreatic cancer xenogeneic mice model, compared with single inhibition of SIRT1, or single gemcitabine therapy. The combination therapy method is a potential treatment method for pancreatic carcinoma.

Lymph node involvement beyond peripancreatic region in pancreatic head cancers: when results belie expectations

OBJECTIVES

Surgery remains the standard therapy for curative management of pancreatic duct adenocarcinoma (PDA) involving the head of pancreas. This study aimed to report our experience in PDA about the prognostic value of lymph node (LN) invasion (N⁺) at the root of the superior mesenteric artery (SMA) and in N2 subgroup.

METHODS

From January 2005 to September 2009, 110 patients were included for pancreaticoduodenectomy or total pancreatectomy.

RESULTS

Etiologies were PDA (n = 87) or ampullary carcinomas (n = 23). Sixty-five percent of patients were N⁺, with N1/N2/N3 location, respectively, 63.6%, 9.1%, and 2.7%. Forty-four percent had a LN identified intraoperatively at the origin of the SMA, of whom only 12% were N⁺. In multivariate analysis (whole series), complication grade greater than II, location of positive LN (N1 to N3) and vascular resection were associated with a poorer survival. In the exocrine PDA subgroup, only location of positive LN and vascular resection were associated with a poorer survival. N⁺ SMA was not statistically correlated with survival, recurrence, or disease-free survival.

CONCLUSIONS

N⁺ at the origin of the SMA was not a significant prognostic factor for PDA and should no longer be considered as a formal contraindication for curative surgery. Conversely, N2 invasion remains an unfavorable prognostic.

Targeted degradation of KRAS by an engineered ubiquitin ligase suppresses pancreatic cancer cell growth in vitro and in vivo

KRAS is an attractive pancreatic ductal adenocarcinoma (PDAC) therapeutic target. E3 ligase is thought to be the component of the ubiquitin conjugation system that is directly responsible for substrate recognition. In this study, an engineered E3 ubiquitin ligase (RC-U) was generated to target the KRAS oncoprotein for ubiquitination and degradation. The engineered E3 ubiquitin ligases (RC-U) were constructed (pRC-U and lentivirus-expressing RC-U). After transfecting the pRC-U plasmid into human pancreatic cancer cells, KRAS expression levels were determined. KRAS expression was also evaluated in cells transfected with pRC-U and treated with MG-132 or cycloheximide. Interactions between RC-U and KRAS as well as whether RC-U could ubiquitinate KRAS were investigated. Extracellular signal-regulated kinase 1/2 (ERK1/2) and phosphorylated ERK 1/2 (pERK1/2) levels were examined in pancreatic cancer cells transfected with pRC-U. The effects of RC-U on pancreatic cancer cell growth were assessed. RC-U decreased KRAS protein levels. After pRC-U transfection, KRAS stability was increased in the presence of MG-132. HEK 293T cells were transfected with a mutant KRAS construct together with pRC-U and incubated with cycloheximide to inhibit new protein synthesis. The exogenous mutant KRAS oncoprotein was degraded more quickly. RC-U can bind KRAS and KRAS can be ubiquitinated by RC-U. pERK1/2 protein levels were decreased. RC-U resulted in reduced cell proliferation in vitro and in vivo. KRAS destruction by RC-U occurred through a ubiquitin-dependent, proteasome-mediated degradation pathway. RC-U inhibited pancreatic cancer cell growth in vitro and in vivo.

Immunoassay-based proteome profiling of 24 pancreatic cancer cell lines

Pancreatic ductal adenocarcinoma is one of the most deadly forms of cancers, with a mortality that is almost identical to incidence. The inability to predict, detect or diagnose the disease early and its resistance to all current treatment modalities but surgery are the prime challenges to changing the devastating prognosis. Also, relatively little is known about pancreatic carcinogenesis. In order to better understand relevant aspects of pathophysiology, differentiation, and transformation, we analysed the cellular proteomes of 24 pancreatic cancer cell lines and two controls using an antibody microarray that targets 741 cancer-related proteins. In this analysis, 72 distinct disease marker proteins were identified that had not been described before. Additionally, categorizing cancer cells in accordance to their original location (primary tumour, liver metastases, or ascites) was made possible. A comparison of the cells' degree of differentiation (well, moderately, or poorly differentiated) resulted in unique marker sets of high relevance. Last, 187 proteins were differentially expressed in primary versus metastatic cancer cells, of which the majority is functionally related to cellular movement.

Crosstalk of Sp1 and Stat3 signaling in pancreatic cancer pathogenesis

Pancreatic cancer progression is attributed to genetic and epigenetic alterations and a chaotic tumor microenvironment. Those diverse "upstream signal" factors appear to converge on specific sets of central nuclear regulators, namely, transcription factors. Specificity Protein 1 (Sp1) and signal transducer and activator of transcription 3 (Stat3) are central transcription factors that regulate a number of pathways important to tumorigenesis, including tumor cell-cycle progression, apoptosis, angiogenesis, metastasis, and evasion of the immune system. Recently, researchers demonstrated many types of crosstalk of Sp1 and Stat3 in tumor signal transduction and that these factors function cooperatively to activate targeted genes and promote tumorigenesis in pancreatic cancer. Therefore, targeting both Sp1 and Stat3 is a potential preventive and therapeutic strategy for pancreatic cancer.

Association of increased DNA methyltransferase expression with carcinogenesis and poor prognosis in pancreatic ductal adenocarcinoma

INTRODUCTION

Epigenetic modifications play an important role in multistage carcinogenesis. The role of the three functional DNA methyltransferases (DNMTs) in pancreatic carcinogenesis has not been fully understood. The main goal of this study was to examine DNMT expression in different stages of pancreatic ductal adenocarcinoma (PDAC), and evaluate their prognostic significance in PDAC.

MATERIALS AND METHODS

A large number of premalignant and malignant pancreatic lesions were obtained by manual microdissection. Quantitative real-time RT-PCR was used to detect DNMTs mRNA expression. Nonparametric test, logrank test and Cox regression analysis were used to evaluate the clinical significance of DNMT expression.

RESULTS

The mRNA expression of the three DNMTs increased with the development of pancreatic cancer from normal duct to pancreatic intraductal neoplasia and further to PDAC, and were statistically correlated with each other. Expression of the three DNMTs was statistically correlated with TNM staging and history of chronic pancreatitis. DNMT3A and DNMT3B, but not DNMT1 expression, was statistically correlated with tumour size. Patients with higher levels of DNMT1, DNMT3A and/or DNMT3B expression had an overall lower survival than those with lower levels of expression. Univariate analysis showed that high expression levels of DNMTs, alcohol consumption, tumour differentiation and TNM staging were statistically significant risk factors. Multivariate analysis showed that high level of DNMT3B expression and tumour differentiation were statistically significant independent poor prognostic factors.

CONCLUSIONS

These results suggested that pancreatic carcinogenesis involves an increased mRNA expression of three DNMTs, and they may become valuable diagnostic and prognostic markers as well as potential therapeutic targets for pancreatic cancer.

Long noncoding intronic RNAs are differentially expressed in primary and metastatic pancreatic cancer

Background

Pancreatic ductal adenocarcinoma (PDAC) is known by its aggressiveness and lack of effective therapeutic options. Thus, improvement in current knowledge of molecular changes associated with pancreatic cancer is urgently needed to explore novel venues of diagnostics and treatment of this dismal disease. While there is mounting evidence that long noncoding RNAs (lncRNAs) transcribed from intronic and intergenic regions of the human genome may play different roles in the regulation of gene expression in normal and cancer cells, their expression pattern and biological relevance in pancreatic cancer is currently unknown. In the present work we investigated the relative abundance of a collection of lncRNAs in patients' pancreatic tissue samples aiming at identifying gene expression profiles correlated to pancreatic cancer and metastasis.

Methods

Custom 3,355-element spotted cDNA microarray interrogating protein-coding genes and putative lncRNA were used to obtain expression profiles from 38 clinical samples of tumor and non-tumor pancreatic tissues. Bioinformatics analyses were performed to characterize structure and conservation of lncRNAs expressed in pancreatic tissues, as well as to identify expression signatures correlated to tissue histology. Strand-specific reverse transcription followed by PCR and qRT-PCR were employed to determine strandedness of lncRNAs and to validate microarray results, respectively.

Results

We show that subsets of intronic/intergenic lncRNAs are expressed across tumor and non-tumor pancreatic tissue samples. Enrichment of promoter-associated chromatin marks and over-representation of conserved DNA elements and stable secondary structure predictions suggest that these transcripts are generated from independent transcriptional units and that at least a fraction is under evolutionary selection, and thus potentially functional.

Statistically significant expression signatures comprising protein-coding mRNAs and lncRNAs that correlate to PDAC or to pancreatic cancer metastasis were identified. Interestingly, loci harboring intronic lncRNAs differentially expressed in PDAC metastases were enriched in genes associated to the MAPK pathway. Orientation-specific RT-PCR documented that intronic transcripts are expressed in sense, antisense or both orientations relative to protein-coding mRNAs. Differential expression of a subset of intronic lncRNAs (PPP3CB, MAP3K14 and DAPK1 loci) in metastatic samples was confirmed by Real-Time PCR.

Conclusion

Our findings reveal sets of intronic lncRNAs expressed in pancreatic tissues whose abundance is correlated to PDAC or metastasis, thus pointing to the potential relevance of this class of transcripts in biological processes related to malignant transformation and metastasis in pancreatic cancer.

In vivo antitumor effect of cromolyn in PEGylated liposomes for pancreatic cancer

A PEGylated liposomal formulation of cromolyn, composed of dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylcholine (DMPC), distearoylphosphatidylcholine (DSPC) and 1,2-distearoyl-sn-glycero-3-phospho-ethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-mPEG2000), has been developed with the purpose of improving the antitumor activity of cromolyn for human pancreatic adenocarcinoma. In stability study, the amount of proteins adsorbed onto the PEGylated liposomes encapsulating cromolyn was 4.5-fold lower than the non-PEGylated liposome. In vitro study showed that the cromolyn in PEGylated liposome exhibited better anti-proliferative effect in BxPC-3 cells than in Panc-1 cells, which indicates higher level of endogenous S100P protein in BxPC-3 cells than in Panc-1 cells as a target protein for this drug. Moreover, the combination of cromolyn with gemcitabine in PEGylated liposomes demonstrated the strongest cytotoxicity to BxPC-3 pancreatic cancer cells in vitro and the highest anti-tumor activity against the BxPC-3 tumor bearing nude mice in vivo. Thus, this PEGylated liposomal formulation of cromolyn is expected to provide a novel approach to the treatment of pancreatic cancer in the future.

Down-regulation of STAT3 expression by vector-based small interfering RNA inhibits pancreatic cancer growth

AIM: To evaluate the effect of RNA interference (RNAi) mediated silence of signal transduction and activation of transcription (STAT)3 on the growth of human pancreatic cancer cells both in vitro and in vivo.

METHODS: STAT3 specific shRNA was used to silence the expression of STAT3 in pancreatic cancer cell line SW1990. The anti-growth effects of RNAi against STAT3 were studied in vitro and in experimental cancer xenografts in nude mice. The potential pathways involved in STAT3 signaling were detected using reverse transcription polymerase chain reaction and western blotting.

RESULTS: The expression of the STAT3 was inhibited using RNAi in SW1990 cells. RNAi against STAT3 inhibited cell proliferation, induced cell apoptosis and significantly reduced the levels of CyclinD1 and Bcl-xL when compared with parental and control vector-transfected cells. In vivo experiments showed that RNAi against STAT3 inhibited the tumorigenicity of SW1990 cells and significantly suppressed tumor growth when it was directly injected into tumors.

CONCLUSION: STAT3 signaling pathway plays an important role in the progression of pancreatic cancer, and silence of STAT3 gene using RNAi technique may be a novel therapeutic option for treatment of pancreatic cancer.

β2-adrenoceptor blocker synergizes with gemcitabine to inhibit the proliferation of pancreatic cancer cells via apoptosis induction

The stimulation of β2-adrenoceptor, which is a major mediator for chronic stress-induced cancers, has been implicated in the progression in the number of cancer cells, including pancreatic cancer, which remains one of the most aggressive and lethal diseases worldwide. Whether β-adrenoceptor antagonists potentiate gemcitabine, a standard first-line treatment for advanced pancreatic cancer that offers only modest benefit due to acquired chemoresistance, has not been elucidated. Thus, we studied the antiproliferative and apoptotic effects and the underlying mechanisms of gemcitabine combined with the β2-adrenoceptor blocker ICI 118551 (1-[2,3-(dihydro-7-methyl-1H-iden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol), in human pancreatic cancer BxPC-3 and MIA PaCa-2 cells. Results show that ICI 118551 significantly synergized the antiproliferative and pro-apoptotic effects induced by gemcitabine in both BxPC-3 and MIA PaCa-2 cells (P<0.05 combination vs. control or gemcitabine alone). When cells were treated with the combination of gemcitabine and ICI 118551, NF-κB activation was blocked; the expression of Bax protein was substantially increased; and Bcl-2 protein was downregulated. Taken together, the data suggest that ICI 118551 potentiates the antiproliferative effects of gemcitabine by inducing apoptosis in pancreatic cancer cells. Our study implies that this combination may be an effective therapeutic strategy for pancreatic cancer.

Antegrade en bloc distal pancreatectomy with plexus hanging maneuver

INTRODUCTION

Although antegrade en bloc distal pancreatectomy is appropriate for invasive distal pancreatic malignancies, this technique is not easy to perform because the end-point of deep vertical resections cannot be controlled. This report describes the usefulness of the application of hanging maneuver in performing the radical surgery.

METHODS

A tape for guidance is passed in a space behind the bundles of the left celiac and mesenteric plexus, followed by sagittal resection of the distal pancreas exposing the root of the celiac artery and superior mesenteric artery. After dividing the pancreas down to the level of the roots of the celiac and superior arteries, the distal pancreas is dissected from the retroperitoneum in medial to lateral fashion.

RESULTS

This technique was applied in six patients with distal pancreas malignancies, without any positive cancer cells at the resected margin. The mean tumor size was 3.0±0.9 cm. The mean duration of surgery and intraoperative blood loss were 258±71 min and 226±240 ml, respectively.

CONCLUSION

Antegrade en bloc distal pancreatectomy with plexus hanging maneuver is an appropriate technique for treating distal pancreatic malignancies.

Is modified Devine exclusion necessary for gastrojejunostomy in patients with unresectable pancreatobiliary cancer?

PURPOSE

Gastrojejunostomy is often performed as palliative surgery for unresectable pancreatobiliary cancer. Modified Devine exclusion (MDE) is a technical variation of gastrojejunostomy, which partially separates the mid-portion of the stomach. We conducted this study to assess whether MDE is necessary for gastrojejunostomy in patients with unresectable pancreatobiliary cancer.

METHODS

We compared the postoperative results of MDE (n = 26) with those of conventional gastrojejunostomy (CGJ; n = 20) performed palliatively for unresectable pancreatobiliary cancers.

RESULTS

The morbidity rates were 38% after MDE and 50% after CGJ, with 23% and 40% of patients suffering delayed gastric emptying, respectively. Two of the CGJ group patients could never eat again. Modified Devine exclusion slowed the progression of anemia in all of the patients with duodenal bleeding.

CONCLUSION

Modified Devine exclusion may be effective for patients with unresectable pancreatobiliary cancer.

Gemcitabine combined with gum mastic causes potent growth inhibition and apoptosis of pancreatic cancer cells

AIM

To investigate the antiproliferative and apoptotic effects of gemcitabine combined with gum mastic and the underlying mechanisms in human pancreatic cancer cell lines.

METHODS

Cell proliferation and apoptosis were examined using the methyl thiazolyl tetrazolium (MTT) assay and propidium iodine staining, respectively. The expression of Bcl-2, Bax, NF-kappaB p65 subunit, and IkappaBalpha protein was measured using Western blotting.

RESULTS

Gemcitabine 0.01-100 microg/mL inhibited cell proliferation and induced apoptosis in both pancreatic cancer BxPC-3 and COLO 357 cells. Gum mastic 40 microg/mL significantly potentiated the antiproliferative and apoptotic effects of gemcitabine 10 microg/mL after 72-h treatment. When cells were treated with gemcitabine in combination with gum mastic, the IkappaBalpha level was increased, whereas NF-kappaB activation was blocked; the expression of Bax protein was substantially increased, but Bcl-2 protein was down-regulated.

CONCLUSION

Gemcitabine combined with gum mastic causes potent apoptosis in pancreatic cancer cells. The combination may be an effective therapeutic strategy for pancreatic cancer.

Inhibition of osteopontin reduces liver metastasis of human pancreatic cancer xenografts injected into the spleen in a mouse model

PURPOSE

Pancreatic cancer is associated with the poorest prognosis of any digestive cancer due to the high incidence of liver metastasis. This study evaluated the possibility that osteopontin (OPN) RNA interference (RNAi) and anti-OPN antibody (Ab) could have antimetastatic effects.

METHODS

The differential gene expression was measured in a parental cell line, HPC-3, and an established highly liver metastatic cell line, HPC-3H4. This study investigated the effect of OPN RNAi and anti-OPN Ab on the metastatic ability of HPC-3H4 to the liver. An OPN RNAi-expressing vector was introduced into HPC-3H4 cells (HPC-3H4/miOPN), in which OPN production was reduced to the level of the parental HPC-3 cells. Finally, the ability of anti-OPN Ab to suppress liver metastasis was investigated.

RESULTS

Osteopontin was upregulated 11.1-fold in HPC-3H4 in comparison to HPC-3. The metastatic rate of HPC-3H4/miOPN was significantly reduced to 25% in comparison to the 100% metastatic rate of HPC-3H4 and control HPC-3H4/miNeg cells (P < 0.01). The metastatic rate of the group given anti-OPN Ab was 50%.

CONCLUSION

OPN RNAi and anti-OPN Ab had remarkable inhibitory effects against liver metastasis by the pancreatic cancer cell line.