Angiogenesis: a prognostic determinant in pancreatic cancer?

Panoramic tumor microenvironment in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is notorious for its resistance to various treatment modalities. The genetic heterogeneity of PDAC, coupled with the presence of a desmoplastic stroma within the tumor microenvironment (TME), contributes to an unfavorable prognosis. The mechanisms and consequences of interactions among different cell types, along with spatial variations influencing cellular function, potentially play a role in the pathogenesis of PDAC. Understanding the diverse compositions of the TME and elucidating the functions of microscopic neighborhoods may contribute to understanding the immune microenvironment status in pancreatic cancer. As we delve into the spatial biology of the microscopic neighborhoods within the TME, aiding in deciphering the factors that orchestrate this intricate ecosystem. This overview delineates the fundamental constituents and the structural arrangement of the PDAC microenvironment, highlighting their impact on cancer cell biology.

PAK in Pancreatic Cancer-Associated Vasculature: Implications for Therapeutic Response

Angiogenesis has been associated with numbers of solid tumours. Anti-angiogenesis drugs starve tumours of nutrients and oxygen but also make it difficult for a chemo reagent to distribute into a tumour, leading to aggressive tumour growth. Anti-angiogenesis drugs do not appear to improve the overall survival rate of pancreatic cancer. Vessel normalisation is merging as one of the new approaches for halting tumour progression by facilitating the tumour infiltration of immune cells and the delivery of chemo reagents. Targeting p21-activated kinases (PAKs) in cancer has been shown to inhibit cancer cell growth and improve the efficacy of chemotherapy. Inhibition of PAK enhances anti-tumour immunity and stimulates the efficacy of immune checkpoint blockades. Inhibition of PAK also improves Car-T immunotherapy by reprogramming the vascular microenvironment. This review summarizes current research on PAK's role in tumour vasculature and therapeutical response, with a focus on pancreatic cancer.

Therapeutic advances targeting tumor angiogenesis in pancreatic cancer: Current dilemmas and future directions

Pancreatic cancer (PC) is one of the most lethal malignancies, which is generally resistant to various treatments. Tumor angiogenesis is deemed to be a pivotal rate-determining step for tumor growth and metastasis. Therefore, anti-angiogenetic therapy is a rational strategy to treat various cancers. However, numerous clinical trials on anti-angiogenetic therapies for PC are overwhelmingly disappointing. The unique characteristics of tumor blood vessels in PC, which are desperately lacking and highly compressed by the dense desmoplastic stroma, are reconsidered to explore some optimized strategies. In this review, we mainly focus on its specific characteristics of tumor blood vessels, discuss the current dilemmas of anti-angiogenic therapy in PC and their underlying mechanisms. Furthermore, we point out the future directions, including remodeling the abnormal vasculature or even reshaping the whole tumor microenvironment in which they are embedded to improve tumor microcirculation, and then create therapeutic vulnerabilities to the current available therapeutic strategies.

Fractal analysis improves tumour size measurement on computed tomography in pancreatic ductal adenocarcinoma: comparison with gross pathology and multi-parametric MRI

Objectives

Tumour size measurement is pivotal for staging and stratifying patients with pancreatic ductal adenocarcinoma (PDA). However, computed tomography (CT) frequently underestimates tumour size due to insufficient depiction of the tumour rim. CT-derived fractal dimension (FD) maps might help to visualise perfusion chaos, thus allowing more realistic size measurement.

Methods

In 46 patients with histology-proven PDA, we compared tumour size measurements in routine multiphasic CT scans, CT-derived FD maps, multi-parametric magnetic resonance imaging (mpMRI), and, where available, gross pathology of resected specimens. Gross pathology was available as reference for diameter measurement in a discovery cohort of 10 patients. The remaining 36 patients constituted a separate validation cohort with mpMRI as reference for diameter and volume.

Results

Median RECIST diameter of all included tumours was 40 mm (range: 18–82 mm). In the discovery cohort, we found significant (p = 0.03) underestimation of tumour diameter on CT compared with gross pathology (Δdiameter_3D = −5.7 mm), while realistic diameter measurements were obtained from FD maps (Δdiameter_3D = 0.6 mm) and mpMRI (Δdiameter_3D = −0.9 mm), with excellent correlation between the two (R² = 0.88). In the validation cohort, CT also systematically underestimated tumour size in comparison to mpMRI (Δdiameter_3D = −10.6 mm, Δvolume = −10.2 mL), especially in larger tumours. In contrast, FD map measurements agreed excellently with mpMRI (Δdiameter_3D = +1.5 mm, Δvolume = −0.6 mL). Quantitative perfusion chaos was significantly (p = 0.001) higher in the tumour rim (FD_rim = 4.43) compared to the core (FD_core = 4.37) and remote pancreas (FD_pancreas = 4.28).

Conclusions

In PDA, fractal analysis visualises perfusion chaos in the tumour rim and improves size measurement on CT in comparison to gross pathology and mpMRI, thus compensating for size underestimation from routine CT.

Key Points

• CT-based measurement of tumour size in pancreatic adenocarcinoma systematically underestimates both tumour diameter (Δdiameter = −10.6 mm) and volume (Δvolume = −10.2 mL), especially in larger tumours.

• Fractal analysis provides maps of the fractal dimension (FD), which enable a more reliable and size-independent measurement using gross pathology or multi-parametric MRI as reference standards.

• FD quantifies perfusion chaos—the underlying pathophysiological principle—and can separate the more chaotic tumour rim from the tumour core and adjacent non-tumourous pancreas tissue.

NOX4: a potential therapeutic target for pancreatic cancer and its mechanism

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) is one of the seven isoforms of NOX family, which is upregulated in pancreatic cancer cell, mouse model of pancreatic cancer and human pancreatic cancer tissue. NOX4 is a constitutively active enzyme that primarily produces hydrogen peroxide, which exhibits completely different properties from other subtypes of NOX family. More importantly, recent studies illuminate that NOX4 promotes pancreatic cancer occurrence and development in different ways. This review summarizes the potential roles and its mechanism of NOX4 in pancreatic cancer and explores NOX4 as the potential therapeutic target in pancreatic cancer.

The Heterogeneity of the Tumor Microenvironment as Essential Determinant of Development, Progression and Therapy Response of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed at advanced stages and most anti-cancer therapies have failed to substantially improve prognosis of PDAC patients. As a result, PDAC is still one of the deadliest tumors. Tumor heterogeneity, manifesting at multiple levels, provides a conclusive explanation for divergent survival times and therapy responses of PDAC patients. Besides tumor cell heterogeneity, PDAC is characterized by a pronounced inflammatory stroma comprising various non-neoplastic cells such as myofibroblasts, endothelial cells and different leukocyte populations which enrich in the tumor microenvironment (TME) during pancreatic tumorigenesis. Thus, the stromal compartment also displays a high temporal and spatial heterogeneity accounting for diverse effects on the development, progression and therapy responses of PDAC. Adding to this heterogeneity and the impact of the TME, the microbiome of PDAC patients is considerably altered. Understanding this multi-level heterogeneity and considering it for the development of novel therapeutic concepts might finally improve the dismal situation of PDAC patients. Here, we outline the current knowledge on PDAC cell heterogeneity focusing on different stromal cell populations and outline their impact on PDAC progression and therapy resistance. Based on this information, we propose some novel concepts for treatment of PDAC patients.

Pancreatic Cancer Small Extracellular Vesicles (Exosomes): A Tale of Short- and Long-Distance Communication

Simple Summary

Even today, pancreatic cancer still has a dismal prognosis. It is characterized by a lack of early symptoms and thus late diagnosis as well as early metastasis. The majority of patients suffer from pancreatic ductal adenocarcinoma (PDAC). PDACs communicate extensively with cellular components of their microenvironment, but also with distant metastatic niches to facilitate tumor progression and dissemination. This crosstalk is substantially enabled by small extracellular vesicles (sEVs, exosomes) with a size of 30–150 nm that are released from the tumor cells. sEVs carry bioactive cargos that reprogram target cells to promote tumor growth, migration, metastasis, immune evasion, or chemotherapy resistance. Interestingly, sEVs also carry novel diagnostic, prognostic and potentially also predictive biomarkers. Moreover, engineered sEVs may be utilized as therapeutic agents, improving treatment options. The role of sEVs for PDAC development, progression, diagnosis, prognosis, and treatment is the focus of this review.

Abstract

Even with all recent advances in cancer therapy, pancreatic cancer still has a dismal 5-year survival rate of less than 7%. The most prevalent tumor subtype is pancreatic ductal adenocarcinoma (PDAC). PDACs display an extensive crosstalk with their tumor microenvironment (TME), e.g., pancreatic stellate cells, but also immune cells to regulate tumor growth, immune evasion, and metastasis. In addition to crosstalk in the local TME, PDACs were shown to induce the formation of pre-metastatic niches in different organs. Recent advances have attributed many of these interactions to intercellular communication by small extracellular vesicles (sEVs, exosomes). These nanovesicles are derived of endo-lysosomal structures (multivesicular bodies) with a size range of 30–150 nm. sEVs carry various bioactive cargos, such as proteins, lipids, DNA, mRNA, or miRNAs and act in an autocrine or paracrine fashion to educate recipient cells. In addition to tumor formation, progression, and metastasis, sEVs were described as potent biomarker platforms for diagnosis and prognosis of PDAC. Advances in sEV engineering have further indicated that sEVs might once be used as effective drug carriers. Thus, extensive sEV-based communication and applications as platform for biomarker analysis or vehicles for treatment suggest a major impact of sEVs in future PDAC research.

Assessment of tissue perfusion of pancreatic cancer as potential imaging biomarker by means of Intravoxel incoherent motion MRI and CT perfusion: correlation with histological microvessel density as ground truth

Background/objectives

The aim of this study was to compare intravoxel incoherent motion (IVIM) diffusion weighted (DW) MRI and CT perfusion to assess tumor perfusion of pancreatic ductal adenocarcinoma (PDAC).

Methods

In this prospective study, DW-MRI and CT perfusion were conducted in nineteen patients with PDAC on the day before surgery. IVIM analysis of DW-MRI was performed and the parameters perfusion fraction f, pseudodiffusion coefficient D*, and diffusion coefficient D were extracted for tumors, upstream, and downstream parenchyma. With a deconvolution-based analysis, the CT perfusion parameters blood flow (BF) and blood volume (BV) were estimated for tumors, upstream, and downstream parenchyma. In ten patients, intratumoral microvessel density (MVD_tumor) and microvessel area (MVA_tumor) were analyzed microscopically in resection specimens. Correlation coefficients between IVIM parameters, CT perfusion parameters, and histological microvessel parameters in tumors were calculated. Receiver operating characteristic (ROC) analysis was performed for differentiation of tumors and upstream parenchyma.

Results

f_tumor significantly positively correlated with BF_tumor (r = 0.668, p = 0.002) and BV_tumor (r = 0.672, p = 0.002). There were significant positive correlations between f_tumor and MVD_tumor/ MVA_tumor (r ≥ 0.770, p ≤ 0.009) as well as between BF_tumor and MVD_tumor/ MVA_tumor (r ≥ 0.697, p ≤ 0.025). Correlation coefficients between f_tumor and MVD_tumor/ MVA_tumor were not significantly different from correlation coefficients between BF_tumor and MVD_tumor/ MVA_tumor (p ≥ 0.400). Moreover, f, BF, BV, and permeability values (PEM) showed excellent performance in distinguishing tumors from upstream parenchyma (area under the ROC curve ≥0.874).

Conclusions

The study shows that IVIM derived f_tumor and CT perfusion derived BF_tumor similarly reflect vascularity of PDAC and seem to be comparably applicable for the evaluation of tumor perfusion for tumor characterization and as potential quantitative imaging biomarker.

Trial registration

DRKS, DRKS00022227, Registered 26 June 2020, retrospectively registered. https://www.drks.de/drks_web/navigate.do?navigationId=trial. HTML&TRIAL_ID=DRKS00022227.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00382-x.

IL10-modified Human Mesenchymal Stem Cells inhibit Pancreatic Cancer growth through Angiogenesis Inhibition

In the present study, we constructed the recombinant plasmid IL10-PEGFP-C1 and successfully transfected into human mesenchymal stem cells. After culturing for 72 h, the levels of IL6 and TNF-α in the supernatant of the MSCs-IL10 group were significantly lower than the vector group and the control group (17.6 ± 0.68vs73.8 ± 0.8 and 74.4 ± 1.5) µg/L and (65.05 ± 3.8 vs 203.2 ± 2.4 and 201.3 ± 3.7) µg/L, respectively (p < 0.001) .The animal experiments showed that the volume of subcutaneous tumors in the MSCs-IL10 group in vivo was a significantly less level compared to that in MSC control and the blank control groups (76.84 ± 20.11) mm³ vs (518. 344 ± 48.66) mm³, (576.99± 49.88) mm³, (P < 0. 05) and they have a longer life time. Further we found the mass concentrations of IL6 and TNF-α in the blood serum of MSC-IL10 group were lower than the vector group and the control group (64.42 ± 10.9 vs120.83 ± 15.52 and 122.65 ± 13.71) and (40.05 ± 5.63 vs 126.78 ±1.89 and 105.83 ± 2.16) µg/L respectively (p < 0.001). CD31 immunohistochemistry and alginate encapsulation experiments showed tumor angiogenesis were inhibited in MSCs-IL10 group in comparison to the control and vector group (P < 0.001), FITC-labeled dextran intake was also lower than the other groups (P < 0.01). Collectively, this study suggested IL10 could inhibit the growth of the transplanted tumor in vivo and prolong survival of mice, and the primary mechanism may be the indirect inhibition of pro-inflammatory cytokines IL6 and TNF-α secretion and tumor angiogenesis formation.

Angiogenesis in Pancreatic Cancer: Pre-Clinical and Clinical Studies

Angiogenesis is a crucial event in tumor development and progression, occurring by different mechanisms and it is driven by pro- and anti-angiogenic molecules. Pancreatic cancer vascularization is characterized by a high microvascular density, impaired microvessel integrity and poor perfused vessels with heterogeneous distribution. In this review article, after a brief introduction on pancreatic cancer classification and on angiogenesis mechanisms involved in its progression, the pre-clinical and clinical trials conducted in pancreatic cancer treatment using anti-angiogenic inhibitors will be described. Finally, we will discuss the anti-angiogenic therapy paradox between the advantage to abolish vessel supply to block tumor growth and the disadvantage due to reduction of drug delivery at the same time. The purpose is to identify new anti-angiogenic molecules that may enhance treatment regimen.

Microvessel Density and Impact of Angiogenesis on Survival of Resected Pancreatic Cancer Patients: A Systematic Review and Meta-analysis

OBJECTIVES

Angiogenesis plays a major role in tumor progression and metastasis; however, its role in pancreatic cancer (PC) remains unclear. The aim of the study was to explore the cumulative evidence concerning the impact of microvessel density (MVD), an estimator of angiogenesis, on resected PC patients.

METHODS

A systematic review of literature and a meta-analysis of relevant reports were performed. Overall survival and disease-free survival were scrutinized.

RESULTS

One thousand five hundred patients were analyzed. Overall survival (hazard ratio, 2.0; 95% confidence interval, 1.57-2.54; P < 0.001) and disease-free survival (hazard ratio, 1.99; 95% confidence interval, 1.24-3.2; P = 0.004) were in favor of the low-MVD group. Use of CD105 antibody and of a computerized image analysis system was found to significantly reduce the heterogeneity. Disease staging, tumor location, and grading showed significant effect on survival.

CONCLUSIONS

High-MVD expression was strongly associated with poorer survival and recurrence among resected PC patients, demonstrating a negative prognostic value. Use of CD105 antibody and of a computerized image analysis system is recommended in future studies because they reduce heterogeneity of results. The potential role of MVD as a marker to select PC patients who would benefit from antiangiogenetic treatment should be further explored in clinical trials.

Angiogenesis in pancreatic cancer: current research status and clinical implications

Pancreatic cancer is one of the most lethal malignancies worldwide. Although the standard of care in pancreatic cancer has improved, prognoses for patients remain poor with a 5-year survival rate of < 5%. Angiogenesis, namely, the formation of new blood vessels from pre-existing vessels, is an important event in tumor growth and hematogenous metastasis. It is a dynamic and complex process involving multiple mechanisms and is regulated by various molecules. Inhibition of angiogenesis has been an established therapeutic strategy for many solid tumors. However, clinical outcomes are far from satisfying for pancreatic cancer patients receiving anti-angiogenic therapies. In this review, we summarize the current status of angiogenesis in pancreatic cancer research and explore the reasons for the poor efficacy of anti-angiogenic therapies, aiming to identify some potential therapeutic targets that may enhance the effectiveness of anti-angiogenic treatments.

Metformin suppresses tumor angiogenesis and enhances the chemosensitivity of gemcitabine in a genetically engineered mouse model of pancreatic cancer

AIMS

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant diseases and has few effective and reliable therapeutic strategies. The anti-tumor effect of metformin is widely known, however, there is only limited evidence regarding the anti-angiogenesis effect and chemosensitization of metformin and its underlying mechanisms in PDAC.

MAIN METHODS

In the present study, we adopted a spontaneous PDAC mouse model named LSL‑Kras^G12D/+; Trp53^fl/+; Pdx1‑Cre (KPC) mice to explore the mechanism of the modulation of tumor angiogenesis and chemosensitization of metformin by treating KPC mice with metformin, gemcitabine or a combination of the two. H&E staining, Masson staining and immunohistochemical staining were adopted to describe the histopathology and biomarkers of the KPC in different groups.

KEY FINDINGS

Metformin plus gemcitabine reduced tumorigenic potential of PDAC. Specifically, metformin showed an anti-pancreatic stellate cells (PSCs) effect via decreasing the expression of sonic hedgehog (SHH) and then sparked some downstream effects, for example, inhibiting the production of vascular endothelial growth factor (VEGF) in the tumor microenvironment, reducing the formation of tumor neovascularization, attenuating the desmoplastic reaction and enhancing the antitumor effect of gemcitabine.

SIGNIFICANCE

We concluded that metformin suppressed tumor angiogenesis and enhanced the chemosensitivity of gemcitabine via inactivating PSCs in PDAC of KPC mice.

Starvation tactics using natural compounds for advanced cancers: pharmacodynamics, clinical efficacy, and predictive biomarkers

The high mortality associated with oncological diseases is mostly due to tumors in advanced stages, and their management is a major challenge in modern oncology. Angiogenesis is a defined hallmark of cancer and predisposes to metastatic invasion and dissemination and is therefore an important druggable target for cancer drug discovery. Recently, because of drug resistance and poor prognosis, new anticancer drugs from natural sources targeting tumor vessels have attracted more attention and have been used in several randomized and controlled clinical trials as therapeutic options. Here, we outline and discuss potential natural compounds as salvage treatment for advanced cancers from recent and ongoing clinical trials and real-world studies. We also discuss predictive biomarkers for patients' selection to optimize the use of these potential anticancer drugs.

Overexpression of c-kit(CD117), relevant with microvessel density, is an independent survival prognostic factor for patients with HBV-related hepatocellular carcinoma

Background

To explore new biomarkers for indicating the recurrence and prognosis in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients after tumor resection, we investigated the expression and prognostic value of c-kit(CD117) in HBV-related HCC.

Materials and methods

Immunohistochemistry was used to estimate the expression of c-kit(CD117) and CD34 in the liver cancer tissues. The correlations between the expression of these biomarkers and the clinicopathologic characteristics were analyzed.

Results

The positive rate of c-kit(CD117) expression in 206 HCC cases was 48.1%, and c-kit expression was significantly related with CD34-positive microvessel density. CD34-microvessel density numbers were much higher in c-kit(+) HCC tissues than in c-kit(−) HCC tissues (44.13±17.01 vs 26.87±13.16, P=0.003). The expression of c-kit was significantly higher in patients with Edmondson grade III–IV (P<0.001) and TNM stage III (P<0.001). Moreover, Kaplan–Meier survival analysis showed that c-kit (P<0.001) expression was correlated with reduced disease-free survival (DFS). Multivariate analysis identified c-kit as an independent poor prognostic factor of DFS in HCC patients (P<0.001).

Conclusion

Increased c-kit expression could be considered as an independent unfavorable prognostic factor for predicting DFS in HBV-related HCC patients after surgery. These results could be used to identify patients at a higher risk of early tumor recurrence and poor prognosis.

Prognostic role and correlation of CA9, CD31, CD68 and CD20 with the desmoplastic stroma in pancreatic ductal adenocarcinoma

We assessed the prognostic value of hypoxia (carbonic anhydrase 9; CA9), vessel density (CD31), with macrophages (CD68) and B cells (CD20) that can interact and lead to immune suppression and disease progression using scanning and histological mapping of whole-mount FFPE pancreatectomy tissue sections from 141 primarily resectable pancreatic ductal adenocarcinoma (PDAC) samples treated with surgery and adjuvant chemotherapy. Their expression was correlated with clinicopathological characteristics, and overall survival (OS), progression-free survival (PFS), local progression-free survival (LPFS) and distant metastases free-survival (DMFS), also in the context of stroma density (haematoxylin-eosin) and activity (alpha-smooth muscle actin). The median OS was 21 months after a mean follow-up of 20 months (range, 2-69 months). The median tumor surface area positive for CA9 and CD31 was 7.8% and 8.1%, respectively. Although total expression of these markers lacked prognostic value in the entire cohort, nevertheless, high tumor compartment CD68 expression correlated with worse PFS (p = 0.033) and DMFS (p = 0.047). Also, high CD31 expression predicted for worse OS (p = 0.004), PFS (p = 0.008), LPFS (p = 0.014) and DMFS (p = 0.004) in patients with moderate density stroma. High stromal and peripheral compartment CD68 expression predicted for significantly worse outcome in patients with loose and moderate stroma density, respectively. Altogether, in contrast to the current notion, hypoxia levels in PDAC appear to be comparable to other malignancies. CD31 and CD68 constitute prognostic markers in patient subgroups that vary according to tumor compartment and stromal density. Our study provides important insight on the pathophysiology of PDAC and should be exploited for future treatments.

Overexpressions of DLL4 and CD105 are Associated with Poor Prognosis of Patients with Pancreatic Ductal Adenocarcinoma

The aim of this study was to investigate the expression of Delta-like ligand 4(DLL4) and Endoglin(CD105) labeled microvessel density(MVD) in pancreatic ductal adenocarcinoma (PDAC) and evaluate their correlation with major clinicopathologic features and patients' survival. Forty-two pancreatic cancer and 20 normal pancreatic tissues were included in the study. Immunohistochemical staining was employed to assess the expression level of DLL4 both in tumor cells and stromal vascular endothelial cells, as well as CD105 which was used to determine MVD. The relationships of DLL4 and CD105 expression with clinicopathologic parameters and clinical outcome were evaluated. Both DLL4 and CD105-labeled microvessel were observed highly immunostained in PDAC cases, and high expression of DLL4 was positively correlated with MVD. Moreover, the high expression of DLL4 was significantly associated with histological grade, node stage and TNM stage in not only the cancer cells but also stroma; while high expression of CD105 was associated with histological grade, TNM stage, node stage and distant metastasis. In univariant analysis, patients with high expression of DLL4 and CD105 tended to significantly poorer overall survival. Both DLL4 and CD105 were overexpressed in a large proportion of patients with PDAC. The expression of DLL4 was positively correlated with CD105-labeled MVD, indicating DLL4 may involved in angiogenesis. In addition, high DLL4 and CD105 expression correlated with the poor clinical outcome and overall survival in patients with PDAC.

Long-term survival after resection for non-pancreatic periampullary cancer followed by adjuvant intra-arterial chemotherapy and concomitant radiotherapy

BACKGROUND

There is no consensus regarding the optimal adjuvant treatment after resection of non-pancreatic periampullary adenocarcinoma (NPPC; distal common bile duct, ampulla, duodenum).

OBJECTIVES

The present study was conducted to evaluate the impacts on longterm survival and recurrence of adjuvant intra-arterial chemotherapy (IAC) and concomitant radiotherapy (RT) in patients submitted to resection for NPPC or pancreatic ductal adenocarcinoma (PDAC) in a randomized controlled trial.

METHODS

A total of 120 patients with PDAC (n = 62) or NPPC (n = 58) were prestratified at a ratio of 1:1 for tumour origin and randomized. Half of these patients were treated with adjuvant IAC/RT and the other half were treated with surgery alone. Follow-up was completed for all patients up to 5 years after resection or until death.

RESULTS

There was no survival benefit in either the whole group (primary endpoint) or the PDAC group after IAC/RT. In the NPPC group, longterm survival was observed in 10 patients in the IAC/RT group and five patients in the control group: median survival was 37 months and 28 months, respectively. The occurrence of liver metastases was reduced by IAC/RT from 57% to 29% (P = 0.038). Cox regression analysis revealed a substantial effect of IAC/RT on survival (hazard ratio: 0.44, 95% confidence interval 0.23-0.83; P = 0.011).

CONCLUSIONS

This longterm analysis shows that median and longterm survival were improved after IAC/RT in patients with NPPC, probably because of the effective and sustained reduction of liver metastases. The present results illustrate that NPPC requires an adjuvant approach distinct from that in pancreatic cancer and indicate that further investigation of this issue is warranted.

Identification of novel vascular projections with cellular trafficking abilities on the microvasculature of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a nearly lethal neoplasm. It is a remarkably stroma-rich, vascular-poor and hypo-perfused tumour, which prevents efficient drug delivery. Paradoxically, the neoplastic cells have robust glucose uptake, suggesting that the microvasculature has adopted an alternative method for nutrient uptake and cellular trafficking. Using adapted thick tumour section immunostaining and three-dimensional (3D) construction imaging in human tissue samples, we identified an undiscovered feature of the mature microvasculature in advanced PDAC tumours; long, hair-like projections on the basal surface of microvessels that we refer to as 'basal microvilli'. Functionally, these basal microvilli have an actin-rich cytoskeleton and endocytic and exocytic properties, and contain glucose transporter-1 (GLUT-1)-positive vesicles. Clinically, as demonstrated by PET-CT, the tumour microvasculature with the longest and most abundant basal microvilli correlated with high glucose uptake of the PDAC tumour itself. In addition, these basal microvilli were found in regions of the tumour with low GLUT-1 expression, suggesting that their presence could be dependent upon the glucose concentration in the tumour milieu. Similar microvasculature features were also observed in a K-Ras-driven model of murine PDAC. Altogether, these basal microvilli mark a novel pathological feature of PDAC microvasculature. Because basal microvilli are pathological features with endo- and exocytic properties, they may provide a non-conventional method for cellular trafficking in PDAC tumours.

Histological and Molecular Subclassification of Pancreatic and Nonpancreatic Periampullary Cancers: Implications for (Neo) Adjuvant Systemic Treatment

The benefit of adjuvant chemotherapy for resected pancreatic ductal adenocarcinoma (PDAC) has been confirmed in randomized controlled trials. For nonpancreatic periampullary cancers (NPPC) originating from the distal bile duct, duodenum, ampulla, or papilla of Vater, the role of adjuvant therapy remains largely unclear. This review describes methods for distinguishing PDAC from NPPC by means of readily available and recently developed molecular diagnostic methods. The difficulties of reliably determining the exact origin of these cancers pathologically also is discussed. The review also considers the possibility of unintentional inclusion of NPPC in the most important adjuvant trials on PDAC and the subsequent implications for interpretation of the results. The authors conclude that correct determination of the origin of periampullary cancers is essential for clinical management and should therefore be systematically incorporated into clinical practice and future studies.

Pancreatic tumor cell secreted CCN1/Cyr61 promotes endothelial cell migration and aberrant neovascularization

The complex signaling networks between cancer cells and adjacent endothelial cells make it challenging to unravel how cancer cells send extracellular messages to promote aberrant vascularization or tumor angiogenesis. Here, in vitro and in vivo models show that pancreatic cancer cell generated unique microenvironments can underlie endothelial cell migration and tumor angiogenesis. Mechanistically, we find that pancreatic cancer cell secreted CCN1/Cyr61 matricellular protein rewires the microenvironment to promote endothelial cell migration and tumor angiogenesis. This event can be overcome by Sonic Hedgehog (SHh) antibody treatment. Collectively, these studies identify a novel CCN1 signaling program in pancreatic cancer cells which activates SHh through autocrine-paracrine circuits to promote endothelial cell migration and tumor angiogenesis and suggests that CCN1 signaling of pancreatic cancer cells is vital for the regulation of tumor angiogenesis. Thus CCN1 signaling could be an ideal target for tumor vascular disruption in pancreatic cancer.

Progress in research of hypoxia and angiogenesis in pancreatic cancer

Pancreatic cancer remains one of the most lethal solid tumors of the gastrointestinal tract. Hypoxia is the driving force behind angiogenesis in cancer. Angiogenesis is an essential factor for tumors to grow and metastasize. Studies in recent years have demonstrated that hypoxia and angiogenesis play important roles in the pathogenesis of pancreatic cancer. In this paper we will review recent advances in understanding the role of hypoxia and angiogenesis in the pathogenesis of pancreatic cancer.

The diversity between pancreatic head and body/tail cancers: clinical parameters and in vitro models

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) can be divided into head, body and tail cancers according to the anatomy. Distinctions in tissue composition, vascularization and innervations have been clearly identified between the head and body/tail of the pancreas both in embryological development and in histopathology. To understand the postulated genotype difference, we present comprehensive information on two PDAC cell lines as typical representatives originating from pancreatic head and body/tail cancers, respectively.

DATA SOURCE

In the present review, we compare the difference between pancreatic head and body/tail cancers regarding clinical parameters and introducing an in vitro model.

RESULTS

Increasing evidence has shown that tumors at different locations (head vs body/tail) display different clinical presentation (e.g. incidence, symptom), treatment efficiency (e.g. surgery, chemotherapy) and thus patient prognosis. However, the genetic or molecular diversity (e.g. mutations, microRNA) between the two subtypes of PDAC has not been elucidated so far. They present different chemo- and/or radio-resistance, extracellular matrix adhesion and invasiveness, as well as genetic profiles.

CONCLUSION

Genetic and tumor biological diversity exists in PDAC according to the tumor localization.

Intratumoral α-SMA enhances the prognostic potency of CD34 associated with maintenance of microvessel integrity in hepatocellular carcinoma and pancreatic cancer

Microvessel density (MVD) as an angiogenesis predictor is inefficient per se in cancer prognosis. We evaluated prognostic values of combining intratumoral alpha-smooth muscle actin (α-SMA)-positive stromal cell density and MVD after curative resection in hypervascular hepatocellular carcinoma (HCC) and hypovascular pancreatic cancer (PC). Tissue microarrays were constructed from tumors of 305 HCC and 57 PC patients who underwent curative resection and analyzed for α-SMA and CD34 expression by immunostaining. Prognostic values of these two proteins and other clinicopathological features were examined. Both low α-SMA density and high MVD-CD34 were associated in HCC with the presence of intrahepatic metastasis and microvascular invasion, and they were related to lymph node involvement and microvascular invasion in PC (p<0.05). Although CD34 alone, but not α-SMA, was an independent prognostic factor for overall survival and recurrence-free survival, the combination of low α-SMA and high CD34 was a predictor of worst prognosis for both types of tumors and had a better power to predict patient death and early recurrence (p<0.01). Furthermore, the results show that distribution of most of the α-SMA-positive cells and vascular endothelial cells overlap, showing major colocalization on vascular walls. Poor microvessel integrity, as indicated by high MVD, together with low perivascular α-SMA-positive cell coverage is associated with early recurrence, unfavorable metastasis, and short survival after tumor resection. This finding highlights the significance of vascular quality in tumor progression, which provides an optimized complement to vascular quantity in prognosis of postoperative patients.

High microvessel density in pancreatic ductal adenocarcinoma is associated with high grade

The objectives of this work are to study angiogenesis in pancreatic ductal adenocarcinoma using computerized morphometric and image analysis and to compare the microvascular density in intratumoral and peritumoral areas and normal pancreatic tissue. Microvascular density was analyzed in 60 cases of pancreatic ductal adenocarcinoma and 30 samples of normal pancreatic tissue using an avidin-biotin immunoperoxidase technique with an anti-CD31 antibody. Microvascular density (MVD) was analyzed through digital microimaging and computerized analysis. The blood vessel density in the tumor was significantly higher than in peritumoral areas and in normal pancreatic tissue. Well differentiated pancreatic ductal adenocarcinomas contained higher MVD than poorly differentiated carcinomas. In pancreatic adenocarcinoma, MVD is higher than in peritumoral tissue or normal pancreatic tissue.

Nestin: A novel angiogenesis marker and possible target for tumor angiogenesis

Abnormal vasculature, termed tumor vessels, is a hallmark of solid tumors. The degree of angiogenesis is associated with tumor aggressiveness and clinical outcome. Therefore, exact quantification of tumor vessels is useful to evaluate prognosis. Furthermore, selective detection of newly formed tumor vessels within cancer tissues using specific markers raises the possibility of molecular targeted therapy via the inhibition of tumor angiogenesis. Nestin, an intermediate filament protein, is reportedly expressed in repair processes, various neoplasms, and proliferating vascular endothelial cells. Nestin expression is detected in endothelial cells of embryonic capillaries, capillaries of the corpus luteum, which replenishes itself by angiogenesis, and proliferating endothelial progenitor cells, but not in mature endothelial cells. Therefore, expression of nestin is relatively limited to proliferating vascular endothelial cells and endothelial progenitor cells. Nestin expression is also reported in blood vessels within glioblastoma, prostate cancer, colorectal cancer, and pancreatic cancer, and its expression is more specific for newly formed blood vessels than other endothelial cell markers. Nestin-positive blood vessels form smaller vessels with high proliferation activity in tumors. Knockdown of nestin in vascular endothelial cells suppresses endothelial cell growth and tumor formation ability of pancreatic cancers in vivo. Using nestin to more accurately evaluate microvessel density in cancer specimens may be a novel prognostic indicator. Furthermore, nestin-targeted therapy may suppress tumor proliferation via inhibition of angiogenesis in numerous malignancies, including pancreatic cancer. In this review article, we focus on nestin as a novel angiogenesis marker and possible therapeutic target via inhibition of tumor angiogenesis.