Current Standard and Future Perspectives in First- and Second-Line Treatment of Metastatic Pancreatic Adenocarcinoma

ENO1 contributes to the gemcitabine resistance of pancreatic cancer through the YAP1 signaling pathway

Pancreatic cancer (PC), a leading cause of cancer-related deaths, has a 5-year survival rate of approximately 10%. α-Enolase (ENO1) is a junction channel protein involved in tumor cell apoptosis and chemoresistance. However, the role of ENO1 in PC remains unclear. The expression and prognosis of ENO1 levels were determined in PC using public databases based on The Cancer Genome Atlas (TCGA) data sets. Cell viability, half maximal inhibitory concentration (IC50), autophagy, apoptosis, and autophagy markers were examined using cell counting kit-8 (CCK-8), transmission electron microscope, flow cytometry assays, and immunoblot, respectively. Using the Gene Expression Omnibus (GEO) and TCGA data sets, we found that ENO1 was significantly enriched in PC tumor tissues, and high expression levels of ENO1 were associated with an unfavorable prognosis. Whereas ENO1 silencing suppressed proliferation, autophagy, and induced cell apoptosis in PC cells, and inhibited tumor growth in vivo. Mechanistically, knockdown of ENO1 enhanced cellular cytotoxicity of gemcitabine (GEM), as well as reducing the expression of yes-associated protein 1 (YAP1), a major downstream effector of the Hippo pathway in vitro. YAP1 promoted autophagy and protected PC cells from GEM-induced apoptotic cell death. Furthermore, YAP1 overexpression attenuated the inhibition effects of ENO1 silencing. Our results suggest that ENO1 overexpression promotes cell growth and tumor progression by increasing the expression of YAP1 in PC. Further studies are required to understand the detailed mechanisms between ENO1 and YAP1 in PC.

The role of biliary events in treatment and survival of patients with advanced pancreatic ductal adenocarcinoma

BACKGROUND

Systemic chemotherapy (CT) is the treatment of choice for advanced pancreatic ductal adenocarcinoma (PDAC). Biliary obstruction is common in this setting and may interfere with CT administration due to jaundice or cholangitis related to biliary stent malfunction.

AIMS

To evaluate the impact of biliary events on CT administration and survival in patients with stage III-IV PDAC.

METHODS

Patients enrolled in a randomized trial of nab-paclitaxel plus gemcitabine with/without capecitabine and cisplatin in advanced PDAC were included. Data on management of jaundice, biliary stents/complications and CT were prospectively collected and retrospectively analyzed. Modified overall (mOS) and progression-free (mPFS) survival were evaluated.

RESULTS

Eighty-eight patients met the inclusion criteria (50% females; median age 65years). Seven of eight (87.5%) patients who placed plastic stents developed biliary complications versus 14/30 (46.7%) with metallic stents (p = 0.071). Patients without biliary complications completed planned CT in 64.2% versus 47.6% of cases (p = 0.207). CT completion was related to longer mOS (17 vs 12 months, p = 0.005) and mPFS (9 vs 6 months, p = 0.011). mOS was shorter when biliary complications occurred (12 vs 17 months, p = 0.937), as was mPFS (6 vs 8 months, p = 0.438).

CONCLUSION

Complications related to biliary obstruction influence chemotherapy completion and survival in patients with advanced PDAC.

Systematic Review of Single-Agent vs. Multi-Agent Chemotherapy for Advanced Pancreatic Adenocarcinoma in Elderly vs. Younger Patients

PURPOSE

To systematically review all studies comparing multi-agent to single-agent chemotherapy in the first and second-line setting for unresectable pancreatic adenocarcinoma, so as to compare the outcomes of young and elderly patients.

METHODS

This review searched three databases for relevant studies. The inclusion criteria were diagnosis of locally advanced or metastatic pancreatic adenocarcinoma, comparison of an elderly versus young population, comparison of single-agent versus multi-agent chemotherapy, data on survival outcomes, and randomised controlled trials. The exclusion criteria were phase I trials, incomplete studies, retrospective analyses, systematic reviews, and case reports. A meta-analysis was performed on second-line chemotherapy in elderly patients.

RESULTS

Six articles were included in this systematic review. Three of these studies explored first-line treatment and three explored second-line treatment. In the subgroup analysis, the meta-analysis showed statistically improved overall survival for elderly patients receiving single-agent second-line treatment.

CONCLUSIONS

This systematic review confirmed that combination chemotherapy improved survival in the first-line treatment of advanced pancreatic adenocarcinoma, regardless of age. The benefit of combination chemotherapy in second-line studies for elderly patients with advanced pancreas cancer was less clear.

Cinematic Rendering: Novel Tool for Improving Pancreatic Cancer Surgical Planning

Pancreatic ductal adenocarcinoma is the third-leading cause of all cancer-related deaths in the US. While 20% of patients have resectable disease at diagnosis, improved control of systemic disease using effective chemotherapeutic regimens allows for aggressive operations involving complex vascular resection and reconstruction. A pancreas protocol computed tomography (PPCT) is the gold standard imaging modality in determining local resectability (degree of tumor-vessel involvement), however, it is limited by the inter-operator variability. While post-processing-3D-rendering helps, it does not allow for real-time dynamic assessment of resectability. A recent development in post-process-rendering called cinematic rendering (CR) overcomes this by utilizing advanced light modeling to generate photorealistic 3D images with enhanced details. Cinematic rendering allows for nuanced visualization of areas of interest. Our preliminary experience, as one of the first centers to incorporate the routine use of CR, has proven very useful in surgical planning. For local determination of resectability, vascular mapping allows for accurate assessment of major arteries and the portovenous system. For the portovenous anatomy it assists in determining the optimal surgical approach (extent of resection, appropriate technique for reconstruction, and need for mesocaval shunting). For arterial anatomy, vessel encasement either represents dissectible involvement via periadventitial dissection or true vessel invasion that is unresectable. CR could potentially provide superior ability than traditional PPCT to discern between the two. Additionally, CR allows for better 3D visualization of arterial anatomic variants which, if not appreciated preoperatively, increases risk of intraoperative ischemia and postoperative complications. Lastly, CR could help avoid unnecessary surgery by enhanced identification of occult metastatic disease that is metastatic disease that is otherwise not appreciated on a standard PPCT.

CD95L Inhibition Impacts Gemcitabine-Mediated Effects and Non-Apoptotic Signaling of TNF-α and TRAIL in Pancreatic Tumor Cells

Despite the potential apoptotic functions, the CD95/CD95L system can stimulate survival as well as pro-inflammatory signaling, particularly through the activation of NFκB. This holds true for the TNF/TNFR and the TRAIL/TRAILR systems. Thus, signaling pathways of these three death ligands converge, yet the specific impact of the CD95/CD95L system in this crosstalk has not been well studied. In this study, we show that gemcitabine stimulates the expression of pro-inflammatory cytokines, such as IL6 and IL8, under the influence of the CD95/CD95L system and the pharmacological inhibitor, sCD95Fc, substantially reduced the expression in two PDAC cell lines, PancTuI-luc and A818-4. The stem cell phenotype was reduced when induced upon gemcitabine as well by sCD95Fc. Moreover, TNF-α as well as TRAIL up-regulate the expression of CD95 and CD95L in both cell lines. Conversely, we detected a significant inhibitory effect of sCD95Fc on the expression of both IL8 and IL6 induced upon TNF-α and TRAIL stimulation. In vivo, CD95L inhibition reduced xeno-transplanted recurrent PDAC growth. Thus, our findings indicate that inhibition of CD95 signaling altered the chemotherapeutic effects of gemcitabine, not only by suppressing the pro-inflammatory responses that arose from the CD95L-positive tumor cells but also from the TNF-α and TRAIL signaling in a bi-lateral crosstalk manner.

Models of pancreatic ductal adenocarcinoma

Although pancreatic cancer remains to be a leading cause of cancer-related deaths in many industrialized countries, there have been major advances in research over the past two decades that provided a detailed insight into the molecular and developmental processes that govern the genesis of this highly malignant tumor type. There is a continuous need for the development and analysis of preclinical and genetically engineered pancreatic cancer models to study the biological significance of new molecular targets that are identified using various genome-wide approaches and to better understand the mechanisms by which they contribute to pancreatic cancer onset and progression. Following an introduction into the etiology of pancreatic cancer, the molecular subtypes, and key signaling pathways, this review provides an overview of the broad spectrum of models for pancreatic cancer research. In addition to conventional and patient-derived xenografting, this review highlights major milestones in the development of chemical carcinogen-induced and genetically engineered animal models to study pancreatic cancer. Particular emphasis was placed on selected research findings of ligand-controlled tumor models and current efforts to develop genetically engineered strains to gain insight into the biological functions of genes at defined developmental stages during cancer initiation and metastatic progression.

First- and Second-Line Palliative Systemic Treatment Outcomes in a Real-World Metastatic Pancreatic Cancer Cohort

BACKGROUND

Metastatic pancreatic ductal adenocarcinoma (PDAC) is characterized by a poor survival rate, which can be improved by systemic treatment. Consensus on the most optimal first- and second-line palliative systemic treatment is lacking. The aim of this study was to describe the use of first- and second-line systemic treatment, overall survival (OS), and time to failure (TTF) of first- and second-line treatment in metastatic PDAC in a real-world setting.

PATIENTS AND METHODS

Patients with synchronous metastatic PDAC diagnosed between 2015 and 2018 who received systemic treatment were selected from the nationwide Netherlands Cancer Registry. OS and TTF were evaluated using Kaplan-Meier curves with log-rank test and multivariable Cox proportional hazard analyses.

RESULTS

The majority of 1,586 included patients received FOLFIRINOX (65%), followed by gemcitabine (18%), and gemcitabine + nab-paclitaxel (13%) in the first line. Median OS for first-line FOLFIRINOX, gemcitabine + nab-paclitaxel, and gemcitabine monotherapy was 6.6, 4.7, and 2.9 months, respectively. Compared to FOLFIRINOX, gemcitabine + nab-paclitaxel showed significantly inferior OS after adjustment for confounders (hazard ratio [HR], 1.20; 95% CI, 1.02-1.41), and gemcitabine monotherapy was independently associated with a shorter OS and TTF (HR, 1.98; 95% CI, 1.71-2.30 and HR, 2.31; 95% CI, 1.88-2.83, respectively). Of the 121 patients who received second-line systemic treatment, 33% received gemcitabine + nab-paclitaxel, followed by gemcitabine (31%) and FOLFIRINOX (10%).

CONCLUSIONS

Based on population-based data in patients with metastatic PDAC, treatment predominantly consists of FOLFIRINOX in the first line and gemcitabine with or without nab-paclitaxel in the second line. FOLFIRINOX in the first line shows superior OS compared with gemcitabine with or without nab-paclitaxel.

Mechanisms of drug resistance of pancreatic ductal adenocarcinoma at different levels

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related death worldwide, and the mortality of patients with PDAC has not significantly decreased over the last few decades. Novel strategies exhibiting promising effects in preclinical or phase I/II clinical trials are often situated in an embarrassing condition owing to the disappointing results in phase III trials. The efficacy of the current therapeutic regimens is consistently compromised by the mechanisms of drug resistance at different levels, distinctly more intractable than several other solid tumours. In this review, the main mechanisms of drug resistance clinicians and investigators are dealing with during the exploitation and exploration of the anti-tumour effects of drugs in PDAC treatment are summarized. Corresponding measures to overcome these limitations are also discussed.

Pancreatic Cancer: Recent Progress of Drugs in Clinical Trials

Pancreatic cancer is a highly malignant tumor and one of the primary causes of cancer-related death. Because pancreatic cancer is difficult to diagnose in the early course of the disease, most patients present with advanced lesions at the time of diagnosis, and only 20% of patients are eligible for surgery. Consequently, drug treatment has become extremely important. At present, the main treatment regimens for pancreatic cancer are gemcitabine and the FORFIRINOX and MPACT regimens. However, none of these regimens substantially improves the prognosis of patients with pancreatic cancer. Extensive efforts have been dedicated to the study of pancreatic cancer in recent years. With the development and clinical application of biological targeted drugs, the biological targeted treatment of tumors has been widely accepted. Therefore, this article used relevant clinical trial data to summarize the research progress of traditional chemotherapy drugs and biological targeted drugs for the treatment of pancreatic cancer.

Extracellular Matrix Composition Modulates the Responsiveness of Differentiated and Stem Pancreatic Cancer Cells to Lipophilic Derivate of Gemcitabine

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Gemcitabine (GEM) is used as the gold standard drug in PDAC treatment. However, due to its poor efficacy, it remains urgent to identify novel strategies to overcome resistance issues. In this context, an intense stroma reaction and the presence of cancer stem cells (CSCs) have been shown to influence PDAC aggressiveness, metastatic potential, and chemoresistance.

METHODS

We used three-dimensional (3D) organotypic cultures grown on an extracellular matrix composed of Matrigel or collagen I to test the effect of the new potential therapeutic prodrug 4-(N)-stearoyl-GEM, called C18GEM. We analyzed C18GEM cytotoxic activity, intracellular uptake, apoptosis, necrosis, and autophagy induction in both Panc1 cell line (P) and their derived CSCs.

RESULTS

PDAC CSCs show higher sensitivity to C18GEM treatment when cultured in both two-dimensional (2D) and 3D conditions, especially on collagen I, in comparison to GEM. The intracellular uptake mechanisms of C18GEM are mainly due to membrane nucleoside transporters' expression and fatty acid translocase CD36 in Panc1 P cells and to clathrin-mediated endocytosis and CD36 in Panc1 CSCs. Furthermore, C18GEM induces an increase in cell death compared to GEM in both cell lines grown on 2D and 3D cultures. Finally, C18GEM stimulated protective autophagy in Panc1 P and CSCs cultured on 3D conditions.

CONCLUSION

We propose C18GEM together with autophagy inhibitors as a valid alternative therapeutic approach in PDAC treatment.

Targeted PARP Inhibition Combined with FGFR1 Blockade is Synthetically Lethal to Malignant Cells in Patients with Pancreatic Cancer

The role and therapeutic promise of poly-ADP ribose polymerase (PARP) inhibitors in anticancer chemotherapy are increasingly being explored, particularly in adjuvant or maintenance therapy, considering their low efficacy as monotherapy agents and their potentiating effects on concurrently administered contemporary chemotherapeutics. Against the background of increasing acquired resistance to FGFR1 inhibitors and our previous work, which partially demonstrated the caspase-3/PARP-mediated antitumor and antimetastatic efficacy of PD173074, a selective FGFR1 inhibitor, against ALDH-high/FGFR1-rich pancreatic ductal adenocarcinoma (PDAC) cells, we investigated the probable synthetic lethality and therapeutic efficacy of targeted PARP inhibition combined with FGFR1 blockade in patients with PDAC. Using bioinformatics-based analyses of gene expression profiles, co-occurrence and mutual exclusivity, molecular docking, immunofluorescence staining, clonogenicity, Western blotting, cell viability or cytotoxicity screening, and tumorsphere formation assays, we demonstrated that FGFR1 and PARP co-occur, form a complex, and reduce survival in patients with PDAC. Furthermore, FGFR1 and PARP expression was upregulated in FGFR1 inhibitor (dasatinib)-resistant PDAC cell lines SU8686, MiaPaCa2, and PANC-1 compared with that in sensitive cell lines Panc0403, Panc0504, Panc1005, and SUIT-2. Compared with the limited effect of single-agent olaparib (PARP inhibitor) or PD173074 on PANC-1 and SUIT-2 cells, low-dose combination (olaparib + PD173074) treatment significantly, dose-dependently, and synergistically reduced cell viability, upregulated cleaved PARP, pro-caspase (CASP)-9, cleaved-CASP9, and cleaved-CASP3 protein expression, and downregulated Bcl-xL protein expression. Furthermore, combination treatment markedly suppressed the clonogenicity and tumorsphere formation efficiency of PDAC cells regardless of FGFR1 inhibitor-resistance status and enhanced RAD51 and γ-H2AX immunoreactivity. In vivo studies have shown that both early and late initiation of combination therapy markedly suppressed tumor xenograft growth and increase in weight, although the effect was more pronounced in the early initiation group. In conclusion, FGFR1 inhibitor-resistant PDAC cells exhibited sensitivity to PD173074 after olaparib-mediated loss of PARP signaling. The present FGFR1/PARP-mediated synthetic lethality proof-of-concept study provided preclinical evidence of the feasibility and therapeutic efficacy of combinatorial FGFR1/PARP1 inhibition in human PDAC cell lines.

Cytosolic 5'-nucleotidase 1A is overexpressed in pancreatic cancer and mediates gemcitabine resistance by reducing intracellular gemcitabine metabolites

BACKGROUND

Cytosolic 5'-nucleotidase 1A (NT5C1A) dephosphorylates non-cyclic nucleoside monophosphates to produce nucleosides and inorganic phosphates. Here, we investigate NT5C1A expression in pancreatic ductal adenocarcinoma (PDAC) and its impact on gemcitabine metabolism and therapeutic efficacy.

METHODS

NT5C1A expression was determined by semiquantitative immunohistochemistry using tissue microarrays. Gemcitabine metabolites and response were assessed in several human and murine PDAC cell lines using crystal violet assays, Western blot, viability assays, and liquid chromatography tandem mass-spectrometry (LC-MS/MS).

FINDINGS

NT5C1A was strongly expressed in tumor cells of a large subgroup of resected PDAC patients in two independent patient cohorts (44-56% score 2 and 8-26% score 3, n = 414). In contrast, NT5C1A was expressed at very low levels in the tumor stroma, and neither stromal nor tumoral expression was a prognostic marker for postoperative survival. In vitro, NT5C1A overexpression increased gemcitabine resistance by reducing apoptosis levels and significantly decreased intracellular amounts of cytotoxic dFdCTP in +NT5C1A tumor cells. Co-culture experiments with conditioned media from +NT5C1A PSCs improved gemcitabine efficacy in tumor cells. In vivo, therapeutic efficacy of gemcitabine was significantly decreased and serum levels of the inactive gemcitabine metabolite dFdU significantly increased in mice bearing NT5C1A overexpressing tumors.

INTERPRETATION

NT5C1A is robustly expressed in tumor cells of resected PDAC patients. Moreover, NT5C1A mediates gemcitabine resistance by decreasing the amount of intracellular dFdCTP, leading to reduced tumor cell apoptosis and larger pancreatic tumors in mice. Further studies should clarify the role of NT5C1A as novel predictor for gemcitabine treatment response in patients with PDAC.

Prognostic factors for survival with nab-paclitaxel plus gemcitabine in metastatic pancreatic cancer in real-life practice: the ANICE-PaC study

Background

Treatment with nab-paclitaxel plus gemcitabine increases survival in patients with metastatic pancreatic cancer. However, the assessment of treatment efficacy and safety in non-selected patients in a real-life setting may provide useful information to support decision-making processes in routine practice.

Methods

Retrospective, multicenter study including patients with metastatic pancreatic cancer, who started first-line treatment with nab-paclitaxel plus gemcitabine between December 2013 and June 2015 according to routine clinical practice. In addition to describing the treatment pattern, overall survival (OS) and progression-free survival (PFS) were assessed for the total sample and the exploratory subgroups based on the treatment and patients’ clinical characteristics.

Results

All 210 eligible patients had a median age of 65.0 years (range 37–81). Metastatic pancreatic adenocarcinoma was recurrent in 46 (21.9%) patients and de novo in 164 (78.1%); 38 (18%) patients had a biliary stent. At baseline, 33 (18.1%) patients had an ECOG performance status ≥2. Patients received a median of four cycles of treatment (range 1–21), with a median duration of 3.5 months; 137 (65.2%) patients had a dose reduction of nab-paclitaxel and/or gemcitabine during treatment, and 33 (17.2%) discontinued treatment due to toxicity. Relative dose intensity (RDI) for nab-paclitaxel, gemcitabine, and the combined treatment was 66.7%. Median OS was 7.2 months (95% CI 6.0–8.5), and median PFS was 5.0 months (95% CI 4.3–5.9); 50 patients achieved either a partial or complete response (ORR 24.6%). OS was influenced by baseline ECOG PS, NLR and CA 19.9, but not by age ≥ 70 years and/or the presence of hepatobiliary stent or RDI < 85%. All included variables, computed as dichotomous, showed a significant contribution to the Cox regression model to build a nomogram for predicting survival in these patients: baseline ECOG 0–1 vs. 2–3 (p = 0.030), baseline NLR > 3 vs. ≤ 3 (p = 0.043), and baseline CA 19.9 > 37 U/mL vs. ≤37 U/mL (p = 0.004).

Conclusions

Nab-Paclitaxel plus gemcitabine remain effective in a real-life setting, despite the high burden of dose reductions and poorer performance of these patients. A nomogram to predict survival using baseline ECOG performance status, NLR and CA 19.9 is proposed.

Pancreatic cancer stem cells: Perspectives on potential therapeutic approaches of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma is one of the most aggressive solid tumours of the pancreas, characterised by a five-year survival rate less than 8%. Recent reports that pancreatic cancer stem cells (PCSCs) contribute to the tumorigenesis, progression, and chemoresistance of pancreatic cancer have prompted the investigation of new therapeutic approaches able to directly target PCSCs. In the present paper the non-cancer related drugs that have been proposed to target CSCs that could potentially combat pancreatic cancer are reviewed and evaluated. The role of some pathways and deregulated proteins in PCSCs as new therapeutic targets are also discussed with a focus on selected specific inhibitors. Finally, advances in the development of nanoparticles for targeting PCSCs and site-specific drug delivery are highlighted, and their limitations considered.

The therapeutic targeting of the FGFR1/Src/NF-κB signaling axis inhibits pancreatic ductal adenocarcinoma stemness and oncogenicity

The aberrant activation of the FGFR signaling is detected in many solid tumors, including pancreatic ductal adenocarcinoma (PDAC), suggesting it as a potential therapeutic target. In this study, we investigated the antitumor and anti-metastasis efficacy of the selective FGFR1 inhibitor, PD173074 in PDAC. We used immunohistochemical and in situ hybridization analyses to demonstrate a strong correlation between FGFR1 amplification and/or expression and disease progression in PDAC patients. We showed that ALDH^high (ALDH+) pancreatic cancer cells exhibited stem cell-like phenotype and expressed higher levels of FGFR1, Src, NF-κB, alongside stemness markers like Oct4 and Sox2, compared to their ALDH^low/null (ALDH-) counterparts, suggesting the preferential activation of the FGFR1/Src/NF-κB signaling axis in pancreatic cancer stem cells (panCSCs). Furthermore, treatment of the ALDH^high/ FGFR1-rich pancreatic cancer cell lines with PD173074, a selective FGFR1 inhibitor, revealed that PD173074 inhibited the proliferation and self-renewal of the panCSCs, and induced their apoptosis by activating caspase-3 and cleaving Poly-ADP ribose Polymerase (PARP). The anti-CSCs effect of PD173074 was associated with decreased expression of Oct4, Sox-2, Nanog, and c-Myc, as well as suppression of XIAP, Bcl2, and survivin expression, dose-dependently. Additionally, activation of cMet, Src, ERK 1/2 and NFκB (p65) was also inhibited by PD173074. Also, of clinical relevance, the disruption of the FGFR1/Src/NF-κB signaling axis positively correlated with poor clinical prognosis among the PDAC patients. We concluded that PD173074 suppresses the tumorigenesis and CSCs-like phenotype of PDAC cells, highlighting its therapeutic efficacy and providing support for its potential use as a therapeutic option for the 'difficult-to-treat', 'quick-to-relapse' PDAC patients. Schematic abstract showing how PD173074 inhibits PDAC growth through selective targeting of FGFR1, suppression of cancer stemness, disruption of the FGFR1/Src/NF-κB signaling axis and activation of the cell death signaling pathway.

The BET inhibitor I-BET762 inhibits pancreatic ductal adenocarcinoma cell proliferation and enhances the therapeutic effect of gemcitabine

As one of the most fatal malignancies, pancreatic ductal adenocarcinoma (PDAC) has significant resistance to the currently available treatment approaches. Gemcitabine, the standard chemotherapeutic agent for locally advanced and metastatic PDAC, has limited efficacy, which is attributed to innate/acquired resistance and the activation of prosurvival pathways. Here, we investigated the in vitro efficacy of I-BET762, an inhibitor of the bromodomain and extraterminal (BET) family of proteins, in treating PDAC cell lines alone and in combination with gemcitabine (GEM). The effect of these two agents was also examined in xenograft PDAC tumors in mice. We found that I-BET762 induced cell cycle arrest in the G0/G1 phase and cell death and suppressed cell proliferation and metastatic stem cell factors in PDAC cells. In addition, the BH3-only protein Bim, which is related to chemotherapy resistance, was upregulated by I-BET762, which increased the cell death triggered by GEM in PDAC cells. Moreover, GEM and I-BET762 exerted a synergistic effect on cytotoxicity both in vitro and in vivo. Furthermore, Bim is necessary for I-BET762 activity and modulates the synergistic effect of GEM and I-BET762 in PDAC. In conclusion, we investigated the effect of I-BET762 on PDAC and suggest an innovative strategy for PDAC treatment.

Immune checkpoint blockade can synergize with radiation therapy, even in tumors resistant to checkpoint monotherapy

Immunotherapy has evolved as a new pillar of cancer treatment during the last decade. The main breakthrough was the development of immune checkpoint blocking (ICB) antibodies, which antagonize inhibitory receptors on T cells and their ligands and thus unleash the cellular immune system against the tumor. ICB showed tremendous effects in several types of cancer. However, only a proportion of the patients suffering from tumors, which are in principle sensitive, benefit from this treatment and other kinds of neoplasia are completely resistant. Great effort is currently being undertaken to distinguish responders from non‐responders, and concepts to turn the latter into the former are urgently required. One approach is to combine ICB with already well‐established treatment strategies, that is, the other mainstays of cancer therapy such as surgery, radiation therapy (RT), and chemotherapy. Depending on the circumstances, both chemotherapy and RT may act either immune suppressively or immune stimulatingly. In this issue of EMBO Molecular Medicine, Azad et al (2017) show that indeed, pancreatic ductal adenocarcinoma, which is resistant to ICB monotherapy, becomes responsive to this treatment by simultaneous RT or chemotherapy.

The expression of genes contributing to pancreatic adenocarcinoma progression is influenced by the respective environment

Pancreatic adenocarcinoma is a highly aggressive malignancy with dismal prognosis and limited curative options. We investigated the influence of organ environments on gene expression in RNU rats by orthotopic and intraportal infusion of Suit2-007luc cells into the pancreas, liver and lung respectively. Tumor tissues from these sites were analyzed by chip array and histopathology. Generated data was analyzed by Chipster and Ingenuity Pathway Analysis (±1.5 expression fold change and p<0.05). Further analysis of functional annotations derived from IPA, was based on selected genes with significant modulation of expression. Comparison of groups was performed by creating ratios from the mean expression values derived from pancreas and respective in vitro values, whereas those from liver and lung were related to pancreas, respectively. Genes of interest from three functional annotations for respective organs were identified by exclusion-overlap analyses. From the resulting six genes, transglutaminase2 (TGM2) was further investigated by various assays. Its knockdown with siRNA induced dose dependent inhibitory and stimulatory effects on cell proliferation and cell migration, respectively. DNA fragmentation indicated apoptotic cell death in response to TGM2 knockdown. Cell cycle analysis by FACS showed that TGM2 knockdown induced G1/S blockade. Therefore, TGM2 and its associated genes may be promising therapeutic targets.

Pancreatic Cancer Chemoresistance to Gemcitabine

Pancreatic ductal adenocarcinoma (PDAC), commonly referred to as pancreatic cancer, ranks among the leading causes of cancer-related deaths in the Western world due to disease presentation at an advanced stage, early metastasis and generally a very limited response to chemotherapy or radiotherapy. Gemcitabine remains a cornerstone of PDAC treatment in all stages of the disease despite suboptimal clinical effects primarily caused by molecular mechanisms limiting its cellular uptake and activation and overall efficacy, as well as the development of chemoresistance within weeks of treatment initiation. To circumvent gemcitabine resistance in PDAC, several novel therapeutic approaches, including chemical modifications of the gemcitabine molecule generating numerous new prodrugs, as well as new entrapment designs of gemcitabine in colloidal systems such as nanoparticles and liposomes, are currently being investigated. Many of these approaches are reported to be more efficient than the parent gemcitabine molecule when tested in cellular systems and in vivo in murine tumor model systems; however, although promising, their translation to clinical use is still in a very early phase. This review discusses gemcitabine metabolism, activation and chemoresistance entities in the gemcitabine cytotoxicity pathway and provides an overview of approaches to override chemoresistance in pancreatic cancer.

Different Survival Benefits of Chinese Medicine for Pancreatic Cancer: How to Choose?

OBJECTIVE

To assess the efficacy of Chinese medicine (CM) on patients with pancreatic cancer (PC) in a retrospective population-based study.

METHODS

Between January 1, 2013, and August 30, 2016, according to whether received Western medicine treatment, the patients were included into either integrative medicine (IM) group or CM group. All enrolled patients were orally administrated with Gexia Zhuyu Decoction () or Liujun Ermu Decoction () by syndrome differentiation, twice a day, last for at least 2 months. The primary end point was overall survival (OS).

RESULTS

A total of 174 patients with PC were enrolled in this study. In stage I/II, the median OS was 20.5 months in the IM group [95% confidence interval (CI), 12.499 to 28.501] and 11.17 months in the CM group (95% CI, 5.160 to 17.180, P=0.015). The 1- and 2-year survival rates for the two groups were 47.0%, 40.0% and 21.0%, 21.0%, respectively. In stage III/IV, median OS was 13.53 months (95% CI, 8.665 to 18.395) in the IM group versus 6.4 months (95% CI, 0.00 to 15.682) in the CM group, respectively (P=0.32). The 1- and 2-year survival rate for the IM and CM groups were 27.0%, 7.0% and 20.0%, 2.0%, respectively.

CONCLUSIONS

Intervention of CM contributes to the different survival benefits for PC in different stages. Multimodality treatment might be a promising strategy for PC patients in early stage. While, in advanced stage, CM might be an alternative candidate for PC patients.

APE1/Ref-1 knockdown in pancreatic ductal adenocarcinoma - characterizing gene expression changes and identifying novel pathways using single-cell RNA sequencing

Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1 or APE1) is a multifunctional protein that regulates numerous transcription factors associated with cancer-related pathways. Because APE1 is essential for cell viability, generation of APE1-knockout cell lines and determining a comprehensive list of genes regulated by APE1 has not been possible. To circumvent this challenge, we utilized single-cell RNA sequencing to identify differentially expressed genes (DEGs) in relation to APE1 protein levels within the cell. Using a straightforward yet novel statistical design, we identified 2837 genes whose expression is significantly changed following APE1 knockdown. Using this gene expression profile, we identified multiple new pathways not previously linked to APE1, including the EIF2 signaling and mechanistic target of Rapamycin pathways and a number of mitochondrial-related pathways. We demonstrate that APE1 has an effect on modifying gene expression up to a threshold of APE1 expression, demonstrating that it is not necessary to completely knockout APE1 in cells to accurately study APE1 function. We validated the findings using a selection of the DEGs along with siRNA knockdown and qRT-PCR. Testing additional patient-derived pancreatic cancer cells reveals particular genes (ITGA1, TNFAIP2, COMMD7, RAB3D) that respond to APE1 knockdown similarly across all the cell lines. Furthermore, we verified that the redox function of APE1 was responsible for driving gene expression of mitochondrial genes such as PRDX5 and genes that are important for proliferation such as SIPA1 and RAB3D by treating with APE1 redox-specific inhibitor, APX3330. Our study identifies several novel genes and pathways affected by APE1, as well as tumor subtype specificity. These findings will allow for hypothesis-driven approaches to generate combination therapies using, for example, APE1 inhibitor APX3330 with other approved FDA drugs in an innovative manner for pancreatic and other cancer treatments.

Current status on the place of FOLFIRINOX in metastatic pancreatic cancer and future directions

Pancreatic cancer (PC) incidence rates are rapidly increasing in developed countries, with half the patients being metastatic at diagnosis. For decades, fluorouracil, then gemcitabine regimens were the preferred palliative first-line options for fit patients with metastatic PC. FOLFIRINOX (a combination of bolus and infusional fluorouracil, leucovorin, irinotecan and oxaliplatin) was introduced to clinical practice in 2010 due to the results of the phase II/III trial (PRODIGE 4/ACCORD 11) comparing FOLFIRINOX with single-agent gemcitabine as first-line treatment for patients with MPC. Median overall survival, progression-free survival, and objective response rate were superior with FOLFIRINOX over gemcitabine and there was prolonged time to definitive deterioration in quality of life. Although FOLFIRINOX was also associated with increased toxicity, mainly febrile neutropenia and diarrhea, there has been rapid uptake of this regimen. This review closely examines optimal management and prevention of toxicities, international recommendations for first-line treatment, and use of modified FOLFIRINOX protocols. In this review, we also look at the potential benefit of FOLFIRINOX in selected groups of patients: second-line therapy, adjuvant chemotherapy, induction therapy in patients with borderline resectable and locally advanced PC. Robust validation of the FOLFIRINOX regimen in these settings requires confirmation in further randomized trials.

Risk factors of liver metastasis from advanced pancreatic adenocarcinoma: a large multicenter cohort study

BACKGROUND

Clinical prognostic parameters of liver metastasis from pancreatic adenocarcinoma have not been specifically identified.This study is to explore the risk factors of liver metastasis in advanced pancreatic adenocarcinoma (PDAC) patients in China.

METHODS

A multicenter cohort study was conducted to explore whether liver metastasis in locally advanced and metastatic PDAC could be reflected by some common laboratory indexes. We collected 1787 advanced PDAC patients from three participating hospitals between 2004 and 2014. The associations between some laboratory indexes and risks of liver metastases were analyzed.

RESULTS

Results have shown that 87% of stage IV patients developed synchronous liver metastasis. Primary tumor location (body/tail vs. head/neck, OR 0.55, 95% CI 0.36-0.83), primary tumor diameter (≥20 mm vs. <20 mm, OR 1.77, 95% CI 1.16-2.70), elevated ALT and AST (OR 1.62, 95% CI 0.92-2.83), and elevated CA19-9 (OR 2.72, 95% CI 1.85-3.99) upon diagnosis are significantly associated with risk of synchronous liver metastasis. Among stage III patients, 30.1% developed metachronous liver metastasis. However, no risk factors were identified among these patients.

CONCLUSIONS

Primary tumor location, diameter, elevated ALT and AST, and increased CA19-9 are independent risk factors of synchronous liver metastasis in PDAC patients.