KrasG12D mutation contributes to regulatory T cell conversion through activation of the MEK/ERK pathway in pancreatic cancer

Genetic alterations have been attributed to the abnormal immune microenvironment in cancer. However, the relationship between the KrasG12D mutation and regulatory T cells (Tregs) in pancreatic cancer remains unclear. In this study, we found that KrasG12D mutation status as determined by ddPCR correlated with high levels of Treg infiltration in resectable pancreatic cancer tissues. Compared to wild-type tumour cells, tumours cells with the KrasG12D mutation were associated with higher levels of Tregs, and knockout of the KrasG12D mutation reversed this effect. In addition, overexpression of the KrasG12D mutation in wild-type Kras tumour cells resulted in conversion of CD4+CD25- T cells into Tregs. We also found that in tumour cells, the KrasG12D mutation activated the MEK/ERK pathway, thereby up-regulating the levels of interleukin-10 (IL-10) and transforming growth factor-β (TGF-β), which induced Treg conversion. In summary, KrasG12D mutation plays a critical role in Treg conversion and contributes to an immunosuppressive tumour microenvironment in pancreatic cancer. These results provide new insights into the relationship between gene mutation and immune escape.

Role of angiogenesis in pancreatic cancer biology and therapy

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, and there is a close parallel between disease mortality and incidence. Malignancy is often diagnosed at an advanced stage due to the lack of early symptoms. For the majority of advanced or metastatic pancreatic cancer patients, therapeutic options are limited. Although several new chemotherapeutic regimens have been developed, the overall response rate remains low. Invasive tumour growth and distant metastasis require angiogenesis, a hallmark of cancer, and angiogenic inhibition is a valuable option for cancer therapy. Some anti-angiogenic drugs have been developed for cancer treatment. This review will focus on the role of angiogenesis and anti-angiogenic treatment strategies as well as combination therapy in pancreatic cancer. Translational information from recent molecular biology and animal studies is also summarized. Finally, the dosing schedule for bevacizumab with other chemotherapeutic protocols for pancreatic cancer treatment is discussed.

PIN1 Maintains Redox Balance via the c-Myc/NRF2 Axis to Counteract Kras-Induced Mitochondrial Respiratory Injury in Pancreatic Cancer Cells

Kras is a decisive oncogene in pancreatic ductal adenocarcinoma (PDAC). PIN1 is a key effector involved in the Kras/ERK axis, synergistically mediating various cellular events. However, the underlying mechanism by which PIN1 promotes the development of PDAC remains unclear. Here we sought to elucidate the effect of PIN1 on redox homeostasis in Kras-driven PDAC. PIN1 was prevalently upregulated in PDAC and predicted the prognosis of the disease, especially Kras-mutant PDAC. Downregulation of PIN1 inhibited PDAC cell growth and promoted apoptosis, partially due to mitochondrial dysfunction. Silencing of PIN1 damaged basal mitochondrial function by significantly increasing intracellular ROS. Furthermore, PIN1 maintained redox balance via synergistic activation of c-Myc and NRF2 to upregulate expression of antioxidant response element driven genes in PDAC cells. This study elucidates a new mechanism by which Kras/ERK/NRF2 promotes tumor growth and identifies PIN1 as a decisive target in therapeutic strategies aimed at disturbing the redox balance in pancreatic cancer. SIGNIFICANCE: This study suggests that antioxidation protects Kras-mutant pancreatic cancer cells from oxidative injury, which may contribute to development of a targeted therapeutic strategy for Kras-driven PDAC by impairing redox homeostasis.

A PD-L2-based immune marker signature helps to predict survival in resected pancreatic ductal adenocarcinoma

BACKGROUND

Programmed cell death protein 1 (PD-1) is a key immune checkpoint that regulates peripheral tolerance and protects against autoimmunity. Programmed death ligand-2 (PD-L2) is a less studied ligand to PD-1 and has yet to be fully explored, especially in pancreatic ductal adenocarcinoma (PDAC).

METHODS

In this study, we performed immunohistochemistry to detect the PD-L2, CD3, CD8, transforming growth factor-β2 (TGF-β2) and FOXP3 levels in paraffin sections from 305 patients with resected PDAC as a training set. Expression levels of intratumoral and stromal immune markers were compared in relation to survival using Kaplan-Meier curves, random survival forest model and survival tree analysis. A multivariable Cox proportional-hazards model of associated markers was used to calculate the risk scores.

RESULTS

PD-L2 was expressed in 71.5% of PDAC samples and showed strong correlations with CD3+, CD8+ T cells and FOXP3+ regulatory T cell densities. High levels of intratumoral PD-L2 and FOXP3 were related to poor survival; only stromal FOXP3 overexpression was associated with worse prognosis. Four patterns generated from survival tree analysis demonstrated that PD-L2lowstromalFOXP3low patients had the longest survival, while PD-L2highintratumoralCD3low patients had the shortest survival (P <  0.001). The area under the curve was 0.631(95% confidence interval (CI): 0.447-0.826) for the immune marker-based signature and 0.549 (95% CI: 0.323-0.829; P <  0.001) for the clinical parameter-based signature, which was consistent with the results in the validation set including 150 patients (P <  0.001). A higher risk score indicated shorter survival and could serve as an independent prognostic factor. PD-L2 was also showed associated with TGF-β2 and other immune molecules based on bioinformatics analysis.

CONCLUSIONS

Our work highlighted PD-L2 as a promising immunotherapeutic target with prognostic value combined with complex tumor infiltrating cells in PDAC.

MUC16 C terminal-induced secretion of tumor-derived IL-6 contributes to tumor-associated Treg enrichment in pancreatic cancer

Pancreatic cancer is the most lethal tumor. CA125 (gene symbol MUC16) is an important serum marker for pancreatic cancer diagnosis and treatment. High serum CA125 is related to metabolic tumor burden and poor prognosis. The circulating Treg subset is another independent prognostic factor for pancreatic cancer. Our unpublished data indicated that the circulating Treg proportion might be related to the serum CA125 level. However, the potential relationship and underlying mechanism of MUC16 and Treg in pancreatic cancer tissues remain unclear. In this study, we found that pancreatic cancer tissues were positive for both MUC16 C terminal (MUC16c) and Foxp3 expression and that their expression was correlated. MUC16c released into the cytoplasm via EGF induction significantly increased IL-6 expression and secretion. The PI3K/AKT pathway may participate in the regulation of IL-6 expression and secretion. By treating CD4+ T cells with IL-6 or co-culturing the cells with pancreatic cancer cells, tumor-derived IL-6 was identified to promote Foxp3 expression and Treg differentiation, which was significantly inhibited by the JAK2 inhibitor AG-490. In sum, our study demonstrated that the relationship between the MUC16c level and Foxp3 expression in the local tumor environment was consistent with that of the serum CA125 level and circulating Treg proportion in the systemic environment. MUC16c promoted Foxp3 expression and tumor-associated Treg enrichment in tumor tissues through tumor-secreted IL-6 activation of the JAK2/STAT3 pathway. These findings may provide deeper insight into potential pancreatic cancer therapy approaches.

The clinicopathological and prognostic significance of PD-L1 expression in pancreatic cancer: A meta-analysis

BACKGROUND

Immunotherapy has shown promise against solid tumors. However, the clinical significance of programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) in pancreatic ductal adenocarcinoma (PDAC) remains unclear. This meta-analysis aimed to analyze the prognostic effect of PD-L1 in PDAC.

DATA SOURCES

Electronic search of the PubMed, Cochrane Library and Web of Science was performed until December 2016. Through database searches, we identified articles describing the relationship between PD-L1 status and PDAC patient prognosis. Meta-analysis was performed to investigate the relationship between PD-1 and overall survival (OS).

RESULTS

Nine studies with 989 PDAC patients were included for PD-L1 expression analysis. And 5 studies with 688 PDAC patients were included in the prognostic analysis. The PD-L1 positive rate measured by immunohistochemistry (IHC) was higher than that measured by polymerase chain reaction (PCR) (P < 0.001). PDAC patients with high expression levels of PD-L1 had significantly reduced OS (HR = 2.34; 95% CI: 1.78-3.08). Subgroup analysis showed that the prognostic effect of PD-L1 levels was similar between the IHC and PCR methods. The PD-L1 positive rate was associated with PDAC T stages; the PD-L1 positive rate in the T3-4 group was higher than that in the T1-2 group (OR = 0.37; P = 0.001).

CONCLUSIONS

High PD-L1 expression levels predicted a poor prognosis in PDAC patients. Thus, PD-L1 status helps determine treatment in PDAC patients.

Hypoxia: a barricade to conquer the pancreatic cancer

Pancreatic cancer (PC) remains one of the most extremely lethal malignancies worldwide due to late diagnosis and early metastasis, with a 1-year overall survival rate of approximately 20%. The hypoxic microenvironment, induced by intratumoral hypoxia, promotes tumor invasion and progression, leading to chemotherapy or radiotherapy resistance and eventual mortality after treatment of PC. However, the role of the hypoxic microenvironment in PC is complicated and requires further investigation. In this article, we review recent advances regarding the regulation of malignant behaviors in PC, which provide insight into the potential of hypoxic microenvironment activation therapy for the therapeutic agents.

Somatostatin receptor expression indicates improved prognosis in gastroenteropancreatic neuroendocrine neoplasm, and octreotide long-acting release is effective and safe in Chinese patients with advanced gastroenteropancreatic neuroendocrine tumors

Gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN) is known to overexpress somatostatin receptors (SSTRs), most commonly SSTR2 and SSTR5. The expression of SSTRs on tumor cells forms the basis for somatostatin analog treatment of patients with NEN. The present study detected the expression of SSTR2 and SSTR5 in GEP-NEN and investigated the efficacy and safety of octreotide long-acting release (LAR) in the treatment of advanced gastroenteropancreatic neuroendocrine tumors (GEP-NET) in China. The present study reported that functionality of the pancreas, G1 and G2 grading, NET classification and Tumor-Node-Metastasis stages I and II were associated with higher SSTR2 positive expression. Similarly, SSTR5 was increased in pancreatic and well-differentiated tumors. SSTR2 and SSTR5 positive expression predicted improved survival in GEP-NEN patients. The median overall survival of patients treated with octreotide LAR was not reached. The median time to progression was 20.2 months, with the objective response rate being 5.6% and the stable disease rate being 79.6%. A total of 25.9% of the patients experienced adverse drug reactions. In conclusion, the present study demonstrated that SSTR2 and SSTR5 are heterogeneously expressed in GEP-NEN. Both markers may serve as potential prognostic factors. Octreotide LAR is effective and safe in the treatment of Chinese patients with advanced GEP-NET.

Circulating regulatory T cell subsets predict overall survival of patients with unresectable pancreatic cancer

Most patients with pancreatic ductal adenocarcinoma (PDAC) have unresectable cancers with a dismal prognosis, in which cohort chemotherapy is the primary treatment. T cell immune adaption is critical for tumor immune escape and prognosis of this disease. The present study aimed to determine the correlation between peripheral T cell subset distribution in patients with unresectable PDAC and their response to chemotherapy. Two hundred and twelve patients with unresectable PDAC were included whose blood samples were collected for analysis of T cell subsets, including CD3+, CD4+, CD8+, CD8+CD28+ and CD4+CD25+CD127 T cells by flow cytometry before and after gemcitabine-based chemotherapy. Enzyme-linked immunosorbent assay was used to detect the expression levels of tumor growth factor (TGF)-β1, interleukin (IL)-6 and IL-17A in the patients before and after chemotherapy. Univariate and multivariate analyses found that an initial CD4/CD8 ratio or T regulatory (Treg) cell level before any treatment was associated with the prognosis of unresectable PDAC. After two cycles of chemotherapy, there was no significant change in percentages of T cell subsets, except elevation to a higher level of CD3+ T cells. Decreased Tregs or CD4/CD8 ratio after two cycles of chemotherapy predicts a longer overall survival (OS). Levels of Tregs in stable disease (SD) and partial remission (PR) cases significantly decreased after chemotherapy, but increased in progressive disease (PD) patients. There was no correlation between Tregs and the expression level of either TGF-β1 or IL-6. IL-17A expression was elevated in Treg-decreased patients, whereas IL-17A was reduced in Treg-increased patients after chemotherapy. The circulating signature of T cell subsets can predict OS and chemotherapeutic response in patients with unresectable PDAC, and may be attributable to the plasticity of T cell subsets.

Novel recurrence risk stratification of resected pancreatic neuroendocrine tumor

Radical surgical resection represents the only hope of cure for pancreatic neuroendocrine tumor (PanNET). Adjuvant therapy is rarely used because there is no evidence to distinguish patients with high recurrence risk. Here we investigated the recurrence feature of resected PanNET and established a novel risk stratification to predict its recurrence. We analyzed 505 PanNET patients who underwent R0 resection at our institute from January 2004 through May 2015. The median follow-up was 71months (range: 12months-143months), 129 patients (25.5%) experienced recurrence with median disease-free survival (mDFS) of 19months. Restricted cubic spline (RCS) functions revealed a positive, linear relationship between Ki-67 index and recurrence. Multivariate analysis showed T stage, N stage, insulinoma and Ki-67 index were independent predictors of recurrence (P < 0.05). Based on scores of these independent factors, we generated a recurrent-risk stage system with HCI of 0.806, superior to TNM stage (HCI 0.704) and grading system (HCI 0.706). Resected PanNET were classified into low risk (65.3%, mDFS not reached), intermediate risk (16.6%, mDFS 48months, 95%CI 26.5-73.4), high risk (13.3%, mDFS 24months, 95%CI 19.4-50.5) and very high risk (4.8%, mDFS 10months, 95%CI 6.9-13.0) (Hazard ratio: 2.650, 95%CI: 2.233-3.145, P < 0.001). This novel risk stratification thus identified PanNET patients of different recurrent-risk. Patients with very high recurrence risk may be suitable for post-operative clinical trials investigating adjuvant treatment.

Follicular Helper T Cells Remodel the Immune Microenvironment of Pancreatic Cancer via Secreting CXCL13 and IL-21

Immunosuppression is an important factor for the poor prognosis of pancreatic ductal adenocarcinoma (PDAC). Follicular helper T cells (Tfh cells) play an anti-tumor role in various malignant solid tumors and predict better patient prognosis. In the present study, we aimed to determine the immunosuppressive mechanism associated with Tfh cells and explore a new strategy to improve the tumor microenvironment of PDAC. Flow cytometry was used to detect the infiltration and proportion of Tfh cells in tumor tissues and peripheral blood from patients with PDAC. The spatial correlations of Tfh cells with related immune cells were evaluated using immunofluorescence. The function of Tfh cells was examined using in vitro and in vivo model systems. The high infiltration of Tfh cells predicted better prognosis in patients with PDAC. Tfh cells recruited CD8+ T cells and B cells by secreting C-X-C motif chemokine ligand 13 (CXCL13), and promoted the maturation of B cells into antibody-producing plasma cells by secreting interleukin 21 (IL-21), thereby promoting the formation of an immunoactive tumor microenvironment. The function of Tfh cells was inhibited by the programmed cell death 1 ligand 1 (PD-L1)/programmed cell death 1 (PD-1) signaling pathway in PDAC, which could be reversed using neoadjuvant chemotherapy. Treatment with recombinant CXCL13, IL-21 and Tfh cells alleviated tumor growth and enhanced the infiltration of CD8+ T cells and B cells, as well as B cell maturation in a PDAC mouse model. Our results revealed the important role of Tfh cells in mediating anti-tumor cellular immunity and humoral immunity in PDAC via secreting CXCL13 and IL-21 and determined a novel mechanism of immunosuppression in PDAC.

Lactate-induced protein lactylation: A bridge between epigenetics and metabolic reprogramming in cancer

Lactate is not only an endpoint of glycolysis but is gradually being discovered to play the role of a universal metabolic fuel for energy via the 'lactate shuttle' moving between cells and transmitting signals. The glycolytic-dependent metabolism found in tumours and fast-growing cells has made lactate a pivotal player in energy metabolism reprogramming, which enables cells to obtain abundant energy in a short time. Moreover, lactate can provide favourable conditions for tumorigenesis by shaping the acidic tumour microenvironment, recruiting immune cells, etc. and the recently discovered lactate-induced lactylation moves even further on pro-tumorigenesis mechanisms of lactate production, circulation and utilization. As with other epigenetic modifications, lactylation can modify histone proteins to alter the spatial configuration of chromatin, affect DNA accessibility and regulate the expression of corresponding genes. What's more, the degree of lactylation is inseparable from the spatialized lactate concentration, which builds a bridge between epigenetics and metabolic reprogramming. Here, we review the important role of lactate in energy reprogramming, summarize the latest finding of lactylation in tumorigenesis and try to explore therapeutic strategies in oncotherapy that can kill two birds with one stone.

Oncogenic KRAS Targets MUC16/CA125 in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with the 5-year survival rate less than 6%. Previous results indicated that serum levels of CA125 (encoded by MUC16) could be used to predict which groups of pancreatic cancer patients may benefit from surgery. However, the underlying mechanism remains elusive. Herein, using the Cancer Genome Atlas and clinicopathologic data obtained from our center, we demonstrate that high CA125 serum levels and expression levels of MUC16 are predictive of poor prognosis. MUC16 is also validated as a downstream target of KRAS, and their expression strongly correlated with each other in vitro and in vivo Mechanistically, the KRAS/ERK axis induced upregulation of MUC16 and shedding of CA125 via its effector c-Myc in SW1990 and PANC-1 pancreatic cancer cells. Notably, proto-oncogene c-Myc could bind to the promoter of MUC16 and transcriptionally activate its expression. Taken together, these data establish CA125 as a prognostic marker for pancreatic cancer, and mechanistic studies uncovered the KRAS/c-Myc axis as a driving factor for upregulation of MUC16.

IMPLICATIONS

The current study uncovers the contribution of oncogenic KRAS to serum marker CA125 production through a mechanism that involves the ERK/c-Myc axis. Mol Cancer Res; 15(2); 201-12. ©2016 AACR.

Hexokinase 2 dimerization and interaction with voltage-dependent anion channel promoted resistance to cell apoptosis induced by gemcitabine in pancreatic cancer

Gemcitabine (GEM) is the standard chemotherapy drug for pancreatic cancer. Because of widespread drug resistance, the effect is limited. Therefore, it is urgent to reveal the underlying mechanism. Glycolysis is the most remarkable character of tumor aberrant metabolism, which plays vital roles on tumor drug resistance. Hexokinase 2 (HK2), as the key enzyme regulating the first-step reaction of glycolysis, is overexpressed in many kinds of tumors. The putative role of HK2 resisting GEM therapy was investigated in this study. We found that HK2 was overexpressed in pancreatic cancer and associated with poor prognosis. HK2 knockdown decreased pancreatic cancer cell proliferation, migration viability, and promoted cell apoptosis in vitro. HK2 high expression in pancreatic cancer showed GEM resistance. HK2 knockdown increased the sensitivity of pancreatic cancer cell to GEM, the growth of xenograft tumor with HK2 knockdown was also further decreased with the GEM treatment compared with control in vivo. GEM-resistant pancreatic cancer showed the increase of HK2 dimer rather than HK2 mRNA or protein. Our study revealed that the ROS derived from GEM promoted HK2 dimerization combining with voltage-dependent anion channel, which resulted in the resistance to GEM. Meanwhile, our study established a new sight for GEM resistance in pancreatic cancer.

Management of solid pseudopapillary neoplasms of pancreas: A single center experience of 243 consecutive patients

BACKGROUND

Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare neoplasm, which mainly affects young women. The aim of this study was to investigate the clinicopathological features and surgical management of SPNs in our institution.

METHODS

Patients who underwent surgery for a pathologically confirmed SPN in our institution between January 2008 and October 2018 were collected. Their clinical characteristics and survival associations were analyzed.

RESULTS

In total, 243 pathologically confirmed patients were analyzed in this study, including 181(74.5%)females and 62(25.5%) males. The mean age was 35.3 years old (range: 12-64 years old) with average tumor size of 4.83 cm (range: 0.8-16 cm). 239 patients underwent complete surgical resection. After median follow-up of 46 months (range: 10-118 months), four patients died due to tumor progression. All the other people were absent of local recurrence or distant metastasis.

CONCLUSIONS

SPN is a latent malignant tumor with excellent prognosis. Surgical resection is recommended even in the presence of liver metastasis. If possible, function-preserving surgery is advocated. High Ki67 index may predict the malignant potential and poor prognosis of SPNs.

CRIP1 fosters MDSC trafficking and resets tumour microenvironment via facilitating NF-κB/p65 nuclear translocation in pancreatic ductal adenocarcinoma

OBJECTIVE

Pancreatic ductal adenocarcinoma (PDAC) is among the most immunosuppressive tumour types. The tumour immune microenvironment (TIME) is largely driven by interactions between immune cells and heterogeneous tumour cells. Here, we aimed to investigate the mechanism of tumour cells in TIME formation and provide potential combination treatment strategies for PDAC patients based on genotypic heterogeneity.

DESIGN

Highly multiplexed imaging mass cytometry, RNA sequencing, mass cytometry by time of flight and multiplex immunofluorescence staining were performed to identify the pro-oncogenic proteins associated with low immune activation in PDAC. An in vitro coculture system, an orthotopic PDAC allograft tumour model, flow cytometry and immunohistochemistry were used to explore the biological functions of cysteine-rich intestinal protein 1 (CRIP1) in tumour progression and TIME formation. RNA sequencing, mass spectrometry and chromatin immunoprecipitation were subsequently conducted to investigate the underlying mechanisms of CRIP1.

RESULTS

Our results showed that CRIP1 was frequently upregulated in PDAC tissues with low immune activation. Elevated CRIP1 expression induced high levels of myeloid-derived suppressor cell (MDSC) infiltration and fostered an immunosuppressive tumour microenvironment. Mechanistically, we primarily showed that CRIP1 bound to nuclear factor kappa-B (NF-κB)/p65 and facilitated its nuclear translocation in an importin-dependent manner, leading to the transcriptional activation of CXCL1/5. PDAC-derived CXCL1/5 facilitated the chemotactic migration of MDSCs to drive immunosuppression. SX-682, an inhibitor of CXCR1/2, blocked tumour MDSC recruitment and enhanced T-cell activation. The combination of anti-PD-L1 therapy with SX-682 elicited increased CD8+T cell infiltration and potent antitumor activity in tumour-bearing mice with high CRIP1 expression.

CONCLUSIONS

The CRIP1/NF-κB/CXCL axis is critical for triggering immune evasion and TIME formation in PDAC. Blockade of this signalling pathway prevents MDSC trafficking and thereby sensitises PDAC to immunotherapy.

GPx1 is involved in the induction of protective autophagy in pancreatic cancer cells in response to glucose deprivation

Given the dense stroma and poor vascularization, access to nutrients is limited in the microenvironment of pancreatic ductal adenocarcinoma (PDA). PDA cells can efficiently recycle various metabolic substrates through the activation of different rescuing pathways, including the autophagy pathway. However, the precise roles of autophagy in cancer metabolism are not yet fully understood. In the present study, we first monitored the effect of glucose deprivation on autophagy and on the expression of glutathione peroxidase-1 (GPx1) in PDA cells under the glucose-free environment. Glucose starvation induced progressive autophagy activation in PDA cells via the activation of ROS/AMPK signaling. GPx1 degradation caused by glucose deprivation led to further ROS-dependent autophagy activation. Both GPx1 overexpression and autophagy inhibition sensitized cells to starvation-induced cell death through the activation of caspase-dependent apoptosis. Moreover, GPx1 may regulate glycolysis inhibition in PDA cells under glucose-deprived conditions. In summary, this study increases our understanding of the role of GPx1 in the induction of protective autophagy in PDA cells under extreme glucose starvation and may provide new therapeutic targets or innovative therapies.

TCF7L2 positively regulates aerobic glycolysis via the EGLN2/HIF-1α axis and indicates prognosis in pancreatic cancer

Patients with pancreatic ductal adenocarcinoma have much worse prognoses, and much effort has been directed toward understanding the molecular biological aspects of this disease. Accumulated evidence suggests that constitutive activation of the Wnt/β-catenin signalling contributes to the oncogenesis and progression of pancreatic cancer. Transcription factor 7-like2/transcription factor 4 (TCF7L2/TCF4), a β-catenin transcriptional partner, plays a vital role in the Wnt/β-catenin signalling pathway. In the present study, we investigated the clinicopathological significance of TCF7L2 in pancreatic cancer. Our results demonstrated that patients with higher TCF7L2 expression had worse prognosis. Our in vitro studies demonstrated that TCF7L2 positively regulated aerobic glycolysis by suppressing Egl-9 family hypoxia inducible factor 2 (EGLN2), leading to upregulation of hypoxia inducible factor 1 alpha subunit (HIF-1α). The impact of TCF7L2 on aerobic glycolysis was further confirmed in vivo by assessing 18FDG uptake in pancreatic cancer patients and in a subcutaneous xenograft mouse model. In summary, we identified novel predictive markers for prognosis and suggest a previously unrecognized role for TCF7L2 in control of aerobic glycolysis in pancreatic cancer.

Precise and efficient silencing of mutant KrasG12D by CRISPR-CasRx controls pancreatic cancer progression

Rationale: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease with few therapeutic targets and rare effective treatments. Over 90% of PDAC tumors bear a Kras mutation, and the single-site mutation G12D (KrasG12D) is most prevalent. Methods: Here, we applied the CRISPR-CasRx system to silence the mutant KrasG12D transcript in PDAC cells. We also used a capsid-optimized adenovirus-associated virus 8 vector (AAV8) to deliver the CRISPR-CasRx system into PDAC orthotopic tumors and patient-derived tumor xenografts (PDX). Results: Our data showed that guided by a KrasG12D-specific gRNA, CasRx is able to precisely and efficiently silence the mutant KrasG12D expression in PDAC cells. The knockdown of mutant KrasG12D by CasRx abolishes the aberrant activation of downstream signaling induced by mutant KrasG12D and subsequently suppresses the tumor growth and improves the sensitivity of gemcitabine in PDAC. Additionally, delivering CasRx-gRNA via AAV8 into the orthotopic KrasG12D PDAC tumors substantially improves the survival of mice without obvious toxicity. Furthermore, targeting KrasG12D through CasRx suppresses the growth of PDAC PDXs. In conclusion, our study provides a proof-of-concept that CRISPR-CasRx can be utilized to target and silence mutant KrasG12D transcripts and therefore inhibit PDAC malignancy.

The Significance of Liquid Biopsy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer. The 5-year survival rate for PDAC remains low because it is always diagnosed at an advanced stage and it is resistant to therapy. A biomarker, which could detect asymptomatic premalignant or early malignant tumors and predict the response to treatment, will benefit patients with PDAC. However, traditional biopsy has its limitations. There is an urgent need for a tumor biomarker that could easily and repeatedly sample and monitor, in real time, the progress of tumor development. Liquid biopsy could be a tool to assess potential biomarkers. In this review, we focused on the latest discoveries and advancements of liquid biopsy technology in pancreatic cancer research and demonstrated how this technology is being used in clinical applications.

Pin1 promotes pancreatic cancer progression and metastasis by activation of NF-κB-IL-18 feedback loop

OBJECTIVES

Accumulated evidence suggests that Pin1 contributes to oncogenesis of diverse cancers. However, the underlying mechanism of oncogenic function of Pin1 in PDAC requires further exploration.

MATERIALS AND METHODS

IHC was performed using PDAC tissues. Western blot, PCR, immunofluorescence and transwell were performed using cell lines. GSEA were applied for possible downstream pathways. ChIP assay and dual luciferase were used for assessment of transcriptional activity.

RESULTS

Both Pin1 and IL-18 levels are increased in primary PDAC tissues and that their levels are positively correlated. High expression of IL-18 is a predictor of poor prognoses. Pin1 promoted pancreatic cancer cell proliferation and motility by increasing IL-18 expression, while Pin1 knockdown also inhibited the tumour-promoting effect of IL-18. Both Pin1 and IL-18 could enhance the NFκB activity in pancreatic cancer cells. When bound to the p65 protein, Pin1 promoted p65 phosphorylation and its nuclear translocation. In the nucleus, Pin1 and p65 simultaneously bound to the IL-18 promoter and enhanced IL-18 transcription. In addition, recruitment of p65 to the IL-18 promoter was decreased in Pin1-silenced cells.

CONCLUSIONS

Our study improves the understanding of Pin1 in tumour-promoting inflammation in PDAC, which is a hallmark of cancer; Pin1 interacted with p65 in PDAC and enhanced NF-κB signalling and downstream transcriptional activation of IL-18, with increased IL-18 continuously activating NF-κB signalling, which then forms a positive feedback loop.

Postoperative serum CEA and CA125 levels are supplementary to perioperative CA19-9 levels in predicting operative outcomes of pancreatic ductal adenocarcinoma

BACKGROUND

Carbohydrate antigen (CA19-9) is a well-established marker to monitor disease status after resection of pancreatic cancer. However, few serum markers have been reported to improve the prognostic ability of postoperative CA19-9, especially in patients with normal postoperative CA19-9.

METHODS

A total of 353 patients with pancreatic ductal adenocarcinoma treated by radical resection were reviewed retrospectively, and a prospective cohort including 142 patients with resectable pancreatic head carcinoma was analyzed as a validation cohort. Perioperative CA19-9 and postoperative serum markers (CEA, CA242, CA72-4, CA50, CA125, CA153, and AFP) were investigated.

RESULTS

Patients with postoperative normalization of CA19-9 had improved survival times (recurrence-free survival: 11.9 months; overall survival: 22.5 months) compared with those with decreased but still elevated postoperative CA19-9 (recurrence-free survival: 6.8 months, P < .001; overall survival: 13.5 months, P < .001) or those with increased postoperative CA19-9 (recurrence-free survival: 3.5 months, P < .001; overall survival: 7.9 months, P < .001), which was similar to those with consistently normal CA19-9 during perioperative periods (recurrence-free survival: 10.6 months, P = .799; overall survival: 24.1 months, P = .756). Normal postoperative CA19-9 levels were an independent indicator for a positive outcome after operation, regardless of preoperative CA19-9 levels. Elevated postoperative CEA and CA125 were identified further as independent risk factors for patients with normal postoperative CA19-9, while elevated postoperative CA125 and nondecreased postoperative CA19-9 were independent prognostic markers for patients with elevated postoperative CA19-9.

CONCLUSION

The postoperative monitoring of CEA and CA125 provided prognostic significance to the measurement of CA19-9 in pancreatic cancer after resection.

Metabolic tumor burden is associated with major oncogenomic alterations and serum tumor markers in patients with resected pancreatic cancer

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.

Optimize CA19-9 in detecting pancreatic cancer by Lewis and Secretor genotyping

BACKGROUND

Carbohydrate antigen 19-9 (CA19-9) is currently the most widely used biomarker for pancreatic cancer. It is well-known that Lewis and Secretor status can affect CA19-9 biosynthesis. This study was performed to optimize CA19-9 in detecting pancreatic cancer using Lewis and Secretor dependent cut-off values.

METHODS

Lewis and Secretor genotypes were determined by Sanger sequencing in a large cohort of subjects (578 cases with pancreatic cancer, 210 cases with benign pancreatic disease, 315 normal subjects). The effectiveness of CA19-9 for detecting pancreatic cancer using Lewis and Secretor group dependent cut-off values was evaluated.

RESULTS

The Lewis (-), Mixed, and Secretor (-) groups had low, medium, and high CA19-9 biosynthesis, respectively. In Lewis (-) pancreatic cancer (all stages), CA19-9 had a sensitivity of 48.6% and a specificity of 95.9% when 1.8 U/mL was used as the cut-off value. The sensitivity of CA19-9 in detecting all stages of pancreatic cancer improved from 80.1% to 88.0% and the negative predictive value increased from 81.2% to 87.1% without compromising other values when using group dependent cut-off values. The sensitivity of CA19-9 for the detection of stage I, II pancreatic cancer increased from 76.1% to 87.2%.

CONCLUSIONS

The value of CA19-9 in detecting pancreatic cancer was optimized by using group dependent cut-off values based on Lewis and Secretor genotypes. CA19-9 can be applied as an early detector of pancreatic cancer using group dependent cut-off values.