Combined modality treatments in pancreatic cancer

How to Choose Between Percutaneous Transhepatic and Endoscopic Biliary Drainage in Malignant Obstructive Jaundice: An Updated Systematic Review and Meta-analysis

BACKGROUND/AIM

Malignant obstructive jaundice (MOJ) is a common condition caused by several primary and secondary cancers. We performed a systematic review and meta-analysis to investigate technical success rate and safety of percutaneous transhepatic biliary drainage (PTBD) versus endoscopic biliary drainage (EBD) in MOJ.

MATERIALS AND METHODS

Relevant trials were identified by searching electronic databases and conference meetings. We included thirteen retrospective studies and four randomized controlled trials, with PTBD performed in 2353 patients and EBD in 8178 patients. Outcomes of interest included: technical success rate, overall complications, 30-day mortality rate and risk of bleeding, pancreatitis, cholangitis and tube dislocation.

RESULTS

The differences in technical success rate, total complications, 30-day mortality rate and tube dislocation were not statistically significant between the two groups. Patients receiving PTBD showed a lower risk of pancreatitis (OR=0.14, 95%CI=0.06-0.31) and cholangitis (OR=0.52, 95%CI=0.30-0.90) when compared to EBD while PTBD was associated with higher risk of bleeding (OR=1.78; 95%CI=1.32-2.39).

CONCLUSION

Our meta-analysis indicates the presence of some advantages and limits for both PTBD and EBD. We highlight the paucity of quality-of-life data, a vital element which should be carefully pondered in future studies and in choosing the optimal technique in patients with MOJ.

Exploring the significance of novel immune-related gene signatures in the prognosis and immune features of pancreatic adenocarcinoma

BACKGROUND

Immune-related genes (IRGs) are associated with the prognosis of different cancers and are helpful for the diagnosis and management of systematic treatment for cancer patients. However, there have been a few corresponding studies in pancreatic adenocarcinoma (PAAD).

METHODS

The data of PAAD patients were obtained from the TCGA, GEO, and ICGC databases. Additionally, the expression profiles of the normal pancreas from the GTEx database were used to screen differentially expressed immune-related genes (DEIRGs). Cox regression analyses were used to explore overall survival (OS)- and progression-free survival (PFS)-related DEIRGs and to establish two nomograms for PAAD prognosis. Finally, transcription factor (TF), immune infiltration, and unsupervised consensus analyses were performed to understand the potential mechanisms.

RESULTS

An OS-prognostic signature based on seven DEIRGs and a PFS-prognostic signature based on seven DEIRGs were generated, and their robust prognostic ability was confirmed by ROC curves (OS: 0.736 ~ 0.774, PFS: 0.732 ~ 0.840). According to the risk score, the OS and PFS of the high-risk group were poorer than those of the low-risk group in the training set and four external validation sets. In addition, two nomograms based on the signatures and clinical variables also showed excellent discrimination. And two hub regulatory pathways were successfully validated in several independent datasets. Discernable patterns of DEIRGs in unsupervised consensus analysis showed that patients with low expression of immune checkpoints had a favorable prognosis.

CONCLUSION

Two DEIRG-based signatures can be used as independent tools for the prognostic prediction of PAAD and to provide potential novel immunotherapy targets.

CXCL9 chemokine promotes the progression of human pancreatic adenocarcinoma through STAT3-dependent cytotoxic T lymphocyte suppression

Chemokines play essential roles in the progression of various human cancers; however, the expression and role of CXC chemokines in pancreatic adenocarcinoma (PAAD) have not yet been identified. The aim of this study is to identify the expression patterns, clinical significance and mechanisms of CXC chemokines in regulating tumour microenvironment of PAAD. Three CXC chemokines, including CXCL5, CXCL9, and CXCL10, were significantly overexpressed in PAAD tissues, which were correlated with the poor survival of the patients. CXCL9/10 was associated with change of immune cell pattern in the tumour microenvironment, and supplementation of CXCL9 in the orthotopic murine PAAD model promoted tumour progression. In particular, CXCL9 reduced the CD8+ cytotoxic T lymphocytes in the tumour microenvironment of PAAD, which could be attributed to the reduced CD8+ T cell proliferation, activation, and secretion of anti-tumour cytokines. In vitro treatment of CXCL9 directly led to the suppression of the proliferation, activation, and secretion of anti-tumour cytokines of isolated CD8+ T cells. Inhibition of STAT3 recovered the CXCL9-inhibited proliferation, activation, and secretion of anti-tumour cytokines of CD8+ T cells. Our study indicates CXCL9 as a potential target of immunotherapy in PAAD treatment by regulating the CD8+ T lymphocytes in the tumour microenvironment.

The Development of a Novel Therapeutic Strategy to Target Hyaluronan in the Extracellular Matrix of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal diseases to affect humans, regardless of whether patients receive multimodal therapy (including surgery, radiotherapy, and chemotherapy). This resistance to intervention is currently considered to be caused by the desmoplastic change of the extracellular matrix (ECM) in PDAC tissues, which is characterized by the accumulation of cancer-associated fibroblasts, collagen, proteoglycan, and hyaluronan. Among these ECM components, hyaluronan has attracted interest because various studies have indicated that hyaluronan-rich PDAC is correlated with the progressive properties of cancer cells, both in experimental and clinical settings. Hence, the reduction of hyaluronan in cancer tissue may represent a novel therapeutic approach for PDAC. 4-methylumbelliferone (4-MU) is a derivative of coumarin that was reported to suppress the synthesis of hyaluronan in cultured human skin fibroblasts in 1995. As an additional study, our group firstly reported that 4-MU reduced the hyaluronan synthesis of mouse melanoma cells and exerted anti-cancer activity. Subsequently, we have showed that 4-MU inhibited liver metastasis in mice inoculated with human pancreatic cancer cells. Thereafter, 4-MU has been accepted as an effective agent for hyaluronan research and is expected to have clinical applications. This review provides an overview of the interaction between PDAC and hyaluronan, the properties of 4-MU as a suppressor of the synthesis of hyaluronan, and the perspectives of PDAC treatment targeting hyaluronan.

Long-Circulating Curcumin-Loaded Liposome Formulations with High Incorporation Efficiency, Stability and Anticancer Activity towards Pancreatic Adenocarcinoma Cell Lines In Vitro

The incorporation of hydrophobic drugs into liposomes improve their bioavailability and leads to increased stability and anticancer activity, along with decreased drug toxicity. Curcumin (Cur) is a natural polyphenol compound with a potent anticancer activity in pancreatic adenocarcinoma (PA). In the present study, different types of Cur-loaded liposomal formulations were prepared and characterized in terms of size, shape, zeta potential, optimal drug-to-lipid ratio and stability at 4°C, 37°C; and in human plasma in vitro. The best formulation in terms of these parameters was PEGylated, cholesterol-free formulation based upon hydrogenated soya PC (HSPC:DSPE-PEG₂₀₀₀:Cur, termed H5), which had a 0.05/10 molar ratio of drug-to-lipid, was found to be stable and had a 96% Cur incorporation efficiency. All Cur-loaded liposomal formulations had potent anticancer activity on the PA cancer cell lines AsPC-1 and BxPC-3, and were less toxic to a normal cell line (NHDF). Furthermore, apoptosis-induction induced by Cur in PA cells was associated with morphological changes including cell shrinkage, cytoplasmic blebbing, irregularity in shape and the externalization of cell membrane phosphatidylserine, which was preceded by an increase in intracellular reactive oxygen species (ROS) generation and caspase 3/7 activation. Because the liposomal formulations tested here, especially the H5 variant which exhibited slow release of the Cur in the human plasma test, the formulation may be stable enough to facilitate the accumulation of pharmacologically active amounts of Cur in target cancer tissue by EPR. Therefore, our formulations could serve as a promising therapeutic approach for pancreatic cancer and other cancers.

Progress in the knowledge and treatment of advanced pancreatic cancer: from benchside to bedside

Ever since a pivotal study in 1997 demonstrated superiority of gemcitabine over 5-FU, gemcitabine monotherapy has, until recently, comprised the standard of care in patients with advanced pancreatic cancer. However, the emerging recognition of the pancreatic cancer microenvironment, including the particularly abundant stroma, as playing a key role in disease progression and resistance to chemotherapy has marked somewhat of a paradigm shift in the way treatment of advanced pancreatic cancer is viewed, with these very same biological defenses conversely offering an Achilles heel with which to combat this aggressive disease. Recently, this approach was validated for the first time in a pivotal phase III trial in which patients received nab-paclitaxel, a stroma-targeted drug, with gemcitabine. Overall survival was significantly (p<0.001) prolonged in the combination arm, compared with gemcitabine alone, and thus these convincing results pave the way forward for future treatment regimens that employ a multipronged approach, targeting not only the primary tumor but the surrounding microenvironment as well.

Recombinant adenovirus-p53 (Gendicine) sensitizes a pancreatic carcinoma cell line to radiation

OBJECTIVE

In this study, we examine the effects of recombinant adenovirus-p53 (rAd-p53) on the pancreatic carcinoma cell line SW1990. Specifically, we determine if expression of rAd-p53 sensitizes these cells to radiation.

METHODS

Following transfection of SW1990 cells with rAd-p53, we measured expression of P53, P21 and Bax by immunocytochemistry. Both transfected and control cell lines were irradiated with a range of doses, and the survival fractions (SF) were calculated. Dose survival curves were constructed and modeled for comparison.

RESULTS

Transfection of SW1990 cells with rAd-p53 resulted in increased expression of P53, P21 and Bax in a time-dependent manner. At 96 h after transfection, 89.92% of cells expressed P53, 56.8% expressed P21, and 76.50% expressed Bax. The SF following radiation was lower in the rAd-p53 transfected cells compared to the control cells, suggesting that rAd-p53 sensitizes SW1990 cells to radiation (D0 for the experimental and control groups was 2.199 and 2.462, respectively).

CONCLUSIONS

Use of the adenoviral vector is an effective means of transfecting SW1990 cells with wild-type P53, and this sensitizes the cell line to irradiation. This work suggests that combining rAd-p53 with radiation therapy in pancreatic cancer may be therapeutically beneficial.

Optimize radiochemotherapy in pancreatic cancer: PARP inhibitors a new therapeutic opportunity

Cancer cells may use PARP enzymes and Homologous Recombination to repair single and double strand breaks caused by genotoxic insults. In this study, the PARP-1 inhibitor Rucaparib was utilized to increase the sensitivity to chemoradiotherapy treatment in BRCA-2-deficient and -proficient pancreatic cancer cells. We used the pancreatic cancer cell lines, Capan-1 with mutated BRCA-2 and Panc-1, AsPC-1 and MiaPaCa-2 with BRCA-1/2 wild type. Cells were treated with Rucaparib and/or radiotherapy (4-10 Gy) plus Gemcitabine then the capability to proliferate was evaluated by colony formation, cell counting and MTT assays. Flow cytometry, immunocytochemistry and western blotting were utilized to assess cell response to Rucaparib plus irradiation. The antitumour effectiveness of combining the PARP-1 inhibitor before, together and after radiotherapy evidenced the first as the optimal schedule in blocking cell growth. Pre-exposure to Rucaparib increased the cytotoxicity of Gemcitabine plus radiotherapy by heavily inducing the accumulation of cells in G2/M phase, impairing mitosis and finally inducing apoptosis and authophagy. The upregulation of p-Akt and downregulation of p53 were evidenced in MiaPaCa-2 which displayed replication stress features. For the first time, the rationale of using a PARP inhibitor as chemoradiosensitizer in pancreatic cancer models has been hypothesized and demonstrated.