Metabolic plasticity in heterogeneous pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal malignant neoplasms. The recognized hallmarks of PDA are regarded to be downstream events of metabolic reprogramming. Because PDA is a heterogeneous disease that is influenced by genetic polymorphisms and changes in the microenvironment, metabolic plasticity is a novel feature of PDA. As intrinsic factors for metabolic plasticity, K-ras activation and mutations in other tumor suppressor genes induce abnormal mitochondrial metabolism and enhance glycolysis, with alterations in glutamine and lipid metabolism. As extrinsic factors, the acidic and oxygen/nutrient-deprived microenvironment also induces cancer cells to reprogram their metabolic pathway and hijack stromal cells (mainly cancer-associated fibroblasts and immunocytes) to communicate, thereby adapting to metabolic stress. Therefore, a better understanding of the metabolic features of PDA will contribute to the development of novel diagnostic and therapeutic strategies.

The Prognostic and Predictive Role of Epidermal Growth Factor Receptor in Surgical Resected Pancreatic Cancer

The data regarding the prognostic significance of EGFR (epidermal growth factor receptor) expression and adjuvant therapy in patients with resected pancreatic cancer are insufficient. We retrospectively investigated EGFR status in 357 resected PDAC (pancreatic duct adenocarcinoma) patients using tissue immunohistochemistry and validated the possible role of EGFR expression in predicting prognosis. The analysis was based on excluding the multiple confounding parameters. A negative association was found between overall EGFR status and postoperative survival (p = 0.986). Remarkably, adjuvant chemotherapy and radiotherapy were significantly associated with favorable postoperative survival, which prolonged median overall survival (OS) for 5.8 and 10.2 months (p = 0.009 and p = 0.006, respectively). Kaplan-Meier analysis showed that adjuvant chemotherapy correlated with an obvious survival benefit in the EGFR-positive subgroup rather than in the EGFR-negative subgroup. In the subgroup analyses, chemotherapy was highly associated with increased postoperative survival in the EGFR-negative subgroup (p = 0.002), and radiotherapy had a significant survival benefit in the EGFR-positive subgroup (p = 0.029). This study demonstrated that EGFR expression is not correlated with outcome in resected pancreatic cancer patients. Adjuvant chemotherapy and radiotherapy were significantly associated with improved survival in contrary EGFR expressing subgroup. Further studies of EGFR as a potential target for pancreatic cancer treatment are warranted.

High Expression of Human Leukocyte Antigen-G is Associated with a Poor Prognosis in Patients with PDAC

Pancreatic Adenocarcinoma (PDAC) is one of the most deadly malignant tumors worldwide. A variety of mechanisms are involved in PDAC biological behaviors, of which, the mechanisms of immune escape may be a pivotal hallmark. HLA-G is a tolerant molecule implicated in tumor escape and serves as a prognostic biomarker in tumors. Our study evaluated the expression of HLA-G in PDAC and explored its clinical significance. In a cohort of 122 PDAC patients, 78 patents (63.9%) exhibited high level of HLA-G tumor tissues. Multivariate analysis suggested that HLA-G level was an independent predictor for OS (HR = 3.894, 95% CI = 2.380-6.370, p <0.001). High level of HLA-G significantly correlated with PDAC aggressive features, such as more advanced stage (TNM Stage II) (p<0.001), extrapancreatic infiltration (T3 stage) (p<0.001), lymph node involvement (p=0.019) and poor differentiation (p=0.010). In western blot analysis, almost all of the tumor cell lines (5/6) expressed high levels of HLA-G. In ELISA analysis, the level of plasma sHLA-G in PDAC patients were significantly increased than in healthy control (P=0.0037). Further analysis revealed the level of sHLA-G inversely related to numbers of peripheral activated T cells (CD8+CD28+ T cells), which may indicate that sHLA-G inactivates T cell responses resulting in tumor immune escape. In conclusion, tumor-derived HLA-G may indicate the mechanism of immune escape and impaired PDAC clinical outcome, especially in early-stage patients, which may also be a potential therapeutic target.

iPSCs Derived from Malignant Tumor Cells: Potential Application for Cancer Research

The development of induced pluripotent stem cell (iPSC) technology has inspired a series of methods to manipulate cell fate and has provided novel insight into the profound molecular events underlying the development of diseases. Reprogramming somatic cells into iPSCs has been intensively investigated. However, few studies have investigated the reprogramming of malignant cells and its potential application. Herein, we review the recent progress of iPSCs derived from malignant cells, and highlight tumor iPSCs applications on cancer research which mainly focus on mesenchymal-epithelial transition, genetic and epigenetic change, diseases model construction, drug screening and tumor pathway study.

Roux-en-Y pancreaticojejunostomy reconstruction after deep enucleation of benign or borderline pancreatic lesions: a single-institution experience

BACKGROUND

Standard pancreatectomy for benign and borderline pancreatic lesions involves resecting a substantial amount of normal pancreatic parenchyma and leads to a subsequent impairment of both exocrine and endocrine pancreatic functions. A limited resection such as enucleation is the preferred option for such neoplasms. However, enucleation is associated with a high risk of postoperative complications in some cases. This study evaluated the feasibility and outcomes of performing deep enucleation with Roux-en-Y pancreaticojejunostomy reconstruction.

METHODS

This study included patients who underwent pancreatic lesion enucleation from February 2010 to April 2014 in our hospital. The clinical data were collected and retrospectively analyzed.

RESULTS

This study examined 53 patients who underwent enucleation, 33 of the procedures included deep enucleation with Roux-en-Y pancreaticojejunostomy reconstruction. There was no mortality, and the morbidity rate was 66.7% in this group. No patients developed grade C pancreatic fistulas in both group. None of the patients developed tumor recurrence or exocrine or endocrine insufficiency at a median follow-up of 25 months.

DISCUSSION

Enucleation with Roux-en-Y pancreaticojejunostomy reconstruction is a safe and feasible procedure for the treatment of benign and borderline pancreatic neoplasms adjacent to the common pancreatic duct. This procedure can effectively mitigate the limitations of simple enucleation.

Mutant p53 determines pancreatic cancer poor prognosis to pancreatectomy through upregulation of cavin-1 in patients with preoperative serum CA19-9 ≥ 1,000 U/mL

Patients with pancreatic ductal adenocarcinoma (PDAC) and preoperative CA19-9 ≥ 1,000 U/mL that does not decrease postresection have the worst prognosis, but the mechanism is unclear. Here, we elucidated the relationship between this signature and driver-gene mutations, and the cavins/caveolin-1 axis. Four major driver-genes (KRAS, TP53, CDKN2A/p16, and SMAD4/DPC4) that are associated with PDAC and five critical molecules (cavin-1/-2/-3/-4 and caveolin-1) in the cavins/caveolin-1 axis were screened by immunohistochemistry in tumor tissue microarrays. Additionally, six pancreatic cancer cell lines and a spleen subcapsular inoculation nude mouse model were also used. Overexpression of mutant p53 was the major mutational event in patients with the CA19-9 signature. Cavin-1 was also overexpressed, and mutant p53 correlated directly with high cavin-1 expression in pancreatic cancer cell lines and tumor specimens (P < 0.01). Furthermore, mutant p53(R172H) upregulated cavin-1 and promoted invasiveness and metastasis of pancreatic cancer cells in vitro and in vivo. Finally, combination of mutant p53 and high cavin-1 density indicated the shortest survival for patients with PDAC after resection (P < 0.001). Mutant p53-driven upregulation of cavin-1 represents the major mechanism of poor outcome for PDAC patients with the CA19-9 signature after resection, indicating that inhibition of cavin-1 may improve the long-term efficacy of pancreatectomy.

The clinical utility of CA125/MUC16 in pancreatic cancer: A consensus of diagnostic, prognostic and predictive updates by the Chinese Study Group for Pancreatic Cancer (CSPAC)

The prognosis for pancreatic cancer (PC) is poor; however, the timely and accurate treatment of this disease will significantly improve prognosis. Serum biomarkers involve non-invasive tests that facilitate the early detection of tumors, predict outcomes and assess responses to therapy, so that the patient can be continuously monitored and receive the most appropriate therapy. Studies have reported that cancer antigen (CA)125 [also known as mucin 16 (MUC16)] has functional significance in the tumorigenic, metastatic and drug resistant properties of PC. Our aim was to use this biomarker in the diagnosis, detection of metastasis, prognosis and in the monitoring of the treatment effects of PC. Members of the Chinese Study Group for Pancreatic Cancer (CSPAC) reviewed the literature on CA125/MUC16 and developed an objective consensus on the clinical utility of CA125/MUC16 for PC. They confirmed the role of CA125/MUC16 in tumorigenesis and the progression of PC, and recommended monitoring CA125/MUC16 levels in all aspects of the diagnosis and treatment of PC, particularly those that involve the monitoring of treatments. In addition, they suggested that the combination of other biomarkers and imaging techniques, together with CA125/MUC16, would improve the accuracy of the clinical decision-making process, thereby facilitating the optimization of treatment strategies. Periodic clinical updates of the use of CA125/MUC16 have been established, which are important for further analyses and comparisons of clinical results from affiliates and countries, particularly as regards the in-depth biological function and clinical translational research of this biomarker.

Pancreatic cancer: BRCA mutation and personalized treatment

The highly heterozygous nature of pancreatic cancer is partially responsible for its therapeutic ineffectiveness and resistance. Therefore, the ability to identify subgroups of pancreatic cancer with unique biological characteristics and treatment response is urgently needed. In addition to breast and ovarian cancer, pancreatic cancer is the third most common cancer type that is related to the early onset (BRCA) gene mutation in breast cancer. Mounting evidence has demonstrated that BRCA1/2-mutant breast and ovarian cancers are highly sensitive to DNA damage-related treatment, including poly(ADP-ribose) polymerase inhibitors (PARPi) and platinum-based agents. Preliminary evidence also showed promising results for DNA damage-related treatment in BRCA1/2-mutant pancreatic cancer. Importantly, several prospective clinical trials of PARPi-based regimens are underway for BRCA1/2-mutated pancreatic cancer. Pancreatic cancer with a BRCA1/2 mutation is a small subgroup with a promising therapeutic strategy.

Should a standard lymphadenectomy during pancreatoduodenectomy exclude para-aortic lymph nodes for all cases of resectable pancreatic head cancer? A consensus statement by the Chinese Study Group for Pancreatic Cancer (CSPAC)

Understanding and formulating an appropriate strategy for the para-aortic lymph nodes (LN16) during curative surgery for pancreatic head cancer have been controversial for some time. This study intended to provide a recommendation for surgeons to perform an optimal curative surgery on pancreatic cancer patients with or without LN16 involvement. Based on an updated literature search and review, the members of the Chinese Study Group for Pancreatic Cancer (CSPAC) from high-volume centers reached a consensus on the issue of LN16 in pancreatic head cancer. Metastasis to LN16 is quite common in pancreatic head cancer cases. Depending on the location of the tumor, including the ventral and dorsal pancreas, there could be various lymph node drainage pathways whereby LN16 does not necessarily belong to the Group 3 lymph node stations for all cases of pancreatic head cancer. Although LN16 involvement generally indicates a poor prognosis, some cohorts of LN16-involved cases have benefited from a curative surgery, and there is still a lack of level I evidence to convince surgeons to abandon all resectable cases with LN16 positivity. Resection of LN16 combined with a standard lymphadenectomy during pancreatoduodenectomy is recommended by CSPAC, except in patients with both positive LN16 and criteria based on: i) the resectability status of primary tumor; ii) the extent of involved para-aortic lymph nodes; and iii) the serum tumor burden assessed preoperatively.

Metabolic tumor burden is associated with major oncogenomic alterations and serum tumor markers in patients with resected pancreatic cancer. Cancer Lett. 2015;360:227-233. [PMID: 25687883 DOI: 10.1016/j.canlet.2015.02.014]

Pancreatic cancer is an aggressive and lethal disease with an overall 5-year survival rate of only 5%. Studies have demonstrated the ability of (18)F-fludrodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) to measure the metabolic tumor burden in patients with various tumors, including pancreatic cancer. In a previous study, we investigated the predictive significance of the metabolic tumor burden in terms of the metabolic tumor volume (MTV) and total lesion glycolysis (TLG). In this study, we analyzed the correlation between metabolic tumor burden and the status of the KRAS, TP53, CDKN2A/p16, and SMAD4/DPC4 genes. Our results showed that the metabolic tumor burden was associated with oncogenomic alterations that reflected the abnormal expression of carbohydrate metabolic enzymes (GLUT1, ALDOA and FBP1). We also identified a linear correlation between serum tumor markers and the metabolic tumor burden. To estimate the metabolic tumor burden when (18)F-FDG PET/CT is not available, we used the linear regression models to establish equations for MTV and TLG using CA19-9 and CA125 as independent variables. Our results suggest that the metabolic tumor burden, as evaluated by (18)F-FDG PET/CT or estimated by serum tumor markers, may be suitable for monitoring treatment response and disease progression of pancreatic cancer. Further research is needed to better understand why pancreatic cancer patients with abnormal expressions of TP53, CDKN2A/p16, and SMAD4/DPC4 get high metabolic tumor burden.