Vasostatin-1: A novel circulating biomarker for ileal and pancreatic neuroendocrine neoplasms

Initial validation of the clinical significance of the NETest in Japanese gastroenteropancreatic neuroendocrine tumor patients

As novel biomarkers for gastroenteropancreatic neuroendocrine tumors (GEPNET) are in demand, we aimed to validate the clinical value of the NETest in Japanese patients. Between 2021 and 2023, blood and clinical data were collected from patients with GEPNET. Among 35 patients (median age: 59 [49-66] years), 27 cases originated from the pancreas and eight from the gastrointestinal tract. Of 69 samples sent to the laboratory, 56 (81.2%) underwent NETest. The diagnostic sensitivity was 97.1%. Among three patients who underwent R0 resection and four treated with peptide receptor radionuclide therapy, the changes in NETest scores closely correlated with disease progression. The NETest demonstrated high diagnostic efficacy and accurate therapeutic monitoring capabilities in a Japanese population.

Recent developments in the diagnosis of pancreatic neuroendocrine neoplasms

INTRODUCTION

Pancreatic Neuroendocrine Neoplasms (PanNENs) are characterized by a highly heterogeneous clinical and biological behavior, making their diagnosis challenging. PanNENs diagnostic work-up mainly relies on biochemical markers, pathological examination, and imaging evaluation. The latter includes radiological imaging (i.e. computed tomography [CT] and magnetic resonance imaging [MRI]), functional imaging (i.e. 68Gallium [68 Ga]Ga-DOTA-peptide PET/CT and Fluorine-18 fluorodeoxyglucose [18F]FDG PET/CT), and endoscopic ultrasound (EUS) with its associated procedures.

AREAS COVERED

This review provides a comprehensive assessment of the recent advancements in the PanNENs diagnostic field. PubMed and Embase databases were used for the research, performed from inception to October 2023.

EXPERT OPINION

A deeper understanding of PanNENs biology, recent technological improvements in imaging modalities, as well as progresses achieved in molecular and cytological assays, are fundamental players for the achievement of early diagnosis and enhanced preoperative characterization of PanNENs. A multimodal diagnostic approach is required for a thorough disease assessment.

Role of chromogranin A-derived fragments after resection of nonfunctioning pancreatic neuroendocrine tumors

PURPOSE

No single reliable biomarker is available for nonfunctioning pancreatic neuroendocrine tumors (NF-PanNETs). Vasostatin-1 (VS-1), the N-terminal fragment of chromogranin A (CgA), seems to be a more accurate biomarker compared to its precursor. Primary aim was to investigate the ability of VS-1, compared to total-CgA, to assess the effectiveness of surgical resection performed for NF-PanNETs. Secondary aim was to evaluate two additional CgA-derived fragments, pancreastatin (PST) and vasostatin-2 (VS-2), as possible biomarkers for NF-PanNETs.

METHODS

Consecutive patients who underwent surgery for NF-PanNETs at San Raffaele Scientific Institute were included (n = 35). Plasma levels of CgA and CgA-derived fragments were measured by Enzyme-Linked ImmunoSorbent Assay (ELISA), preoperatively and postoperatively.

RESULTS

Preoperative VS-1 was significantly higher compared to VS-1 measured on postoperative day 5 (POD5) (pre: 0.338 nM versus POD5: 0.147 nM, P < 0.001), whereas total-CgA significantly increased after surgery (pre: 1.123 nM versus POD5: 1.949 nM, P = 0.006). Overall, 24 patients showed ≥ 1 feature of tumor aggressiveness (T3-T4, nodal/distant metastases, Ki67 > 5%, microvascular/perineural invasion, necrosis). The median percentage decrease in VS-1 plasma levels was 63% (IQR 28-88%) among patients with aggressive tumors, compared to 13% (IQR 0-57%) in the remaining population (P = 0.033). No significant differences in terms of PST (P = 0.870) and VS-2 (P = 0.909) were observed between preoperative and postoperative time.

CONCLUSION

VS-1 provides an early assessment of surgical efficacy in patients who undergo resection for NF-PanNETs, especially in those with aggressive neoplasms. Total-CgA, PST and VS-2 have no clinical utility in this setting.

Chromogranin A plasma levels predict mortality in COVID-19

Background

Chromogranin A (CgA) and its fragment vasostatin I (VS-I) are secreted in the blood by endocrine/neuroendocrine cells and regulate stress responses. Their involvement in Coronavirus 2019 disease (COVID-19) has not been investigated.

Methods

CgA and VS-I plasma concentrations were measured at hospital admission from March to May 2020 in 190 patients. 40 age- and sex-matched healthy volunteers served as controls. CgA and VS-I levels relationship with demographics, comorbidities and disease severity was assessed through Mann Whitney U test or Spearman correlation test. Cox regression analysis and Kaplan Meier survival curves were performed to investigate the impact of the CgA and VS-I levels on in-hospital mortality.

Results

Median CgA and VS-I levels were higher in patients than in healthy controls (CgA: 0.558 nM [interquartile range, IQR 0.358–1.046] vs 0.368 nM [IQR 0.288–0.490] respectively, p = 0.0017; VS-I: 0.357 nM [IQR 0.196–0.465] vs 0.144 nM [0.144–0.156] respectively, p<0.0001). Concentration of CgA, but not of VS-I, significantly increased in patients who died (n = 47) than in survivors (n = 143) (median 0.948 nM [IQR 0.514–1.754] vs 0.507 nM [IQR 0.343–0.785], p = 0.00026). Levels of CgA were independent predictors of in-hospital mortality (hazard ratio 1.28 [95% confidence interval 1.077–1.522], p = 0.005) when adjusted for age, number of comorbidities, respiratory insufficiency degree, C-reactive protein levels and time from symptom onset to sampling. Kaplan Meier curves revealed a significantly increased mortality rate in patients with CgA levels above 0.558 nM (median value, log rank test, p = 0.001).

Conclusion

Plasma CgA levels increase in COVID-19 patients and represent an early independent predictor of mortality.

Vasostatin-1 as a potential novel circulating biomarker in patients with chronic systolic heart failure: A pilot study

BACKGROUND AND AIMS

Previous studies have shown that circulating chromogranin A (CgA) increases in patients with chronic systolic heart failure (HF). Aim of the present study is to evaluate the potential role of circulating vasostatin-1 (VS-1), a cardioregulatory fragment of CgA, as prognostic marker in patients with chronic HF.

MATERIALS AND METHODS

The plasma levels of CgA and VS-1 were determined in 80 patients with chronic systolic HF. Patients were followed-up to evaluate the occurrence of cardiovascular (CV) events.

RESULTS

CgA and VS-1 plasma levels were significantly higher in patients with CV events at follow-up. VS-1, but not CgA, was associated to NT-proBNP. No significant association of CgA and VS-1 with left ventricular ejection fraction (LVEF) was observed. CgA, NT-proBNP and age, but not VS-1, were independent predictors of CV events.

CONCLUSION

In patients with chronic systolic HF those who experienced CV events had higher levels of VS-1 and CgA. Given its established effect on cardiac cells, the association of VS-1 levels with NT-proBNP levels but not with LVEF, suggests that this fragment might provide complementary information to NT-proBNP and CgA in HF patients.

Effect of chromogranin A N-terminal fragment vasostatin-1 nano-carrier transfection on abdominal aortic aneurysm formation

The effects of transfection of N-terminal fragment of chromogranin A Vasostatin-1 (VS-1) nanocarriers on formation of abdominal aortic aneurysm (AAA) were discussed, and its mechanism was analyzed. Nanoparticles containing VS-1 genes were prepared by emulsion solvent evaporation method, and property of nanoparticles was examined. A total of 30 male SD rats were divided randomly into sham group (normal saline), AAA group (Type I porcine pancreatic elastase), and VS-1 group (Type I porcine pancreatic elastase+VS-1 suspension liquid). The diameter dilation of rats was measured, abdominal aortic morphology was observed by HE staining, and levels of AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) were examined by immunohistochemistry and Western blot. Correlation between AMPK as well as mTOR and diameter dilation was analyzed by Pearson correlation. VS-1 genes in VS-1 nanoparticles were 4.51% and coating efficiency of genes was 88%. Compared with rats in sham group, diameter dilation of rats in AAA group increased, damage of abdominal aorta in rats was obvious, p-AMPK decreased, and p-mTOR increased in AAA group. Compared with AAA group, diameter dilation of rats in VS-1 group decreased, abdominal aorta of rats was improved, p-AMPK increased, and p-mTOR decreased. The comparison of all above indicators had statistical meaning (P < 0.05). p-AMPK and p-mTOR were negatively (r = -0.9150 and P = 0.006) and positively correlated with the diameter dilation (r = -0.9206 and P = 0.001). VS-1 nanoparticles could inhibit the formation of AAA, which might be related to the activation of AMPK/mTOR signal path.

Circulating Chromogranin A Is Cleaved Into Vasoregulatory Fragments in Patients With Pancreatic Ductal Adenocarcinoma

Chromogranin A (CgA), a secretory protein released in the blood by the neuroendocrine system, consists of a mixture of full-length molecules and fragments endowed of vasoregulatory activity. The extent and the role of CgA fragmentation were investigated in patients with locally advanced or metastatic pancreatic ductal adenocarcinoma (PDAC, n=172). Multivariate analysis showed that full-length CgA was associated with better progression free and overall survival, whereas CgA C-terminal fragmentation was associated with worse prognosis. In vitro studies showed that PDAC cells can promote the cleavage of CgA C-terminal region by activating plasminogen to plasmin. Limited digestion of full-length CgA with plasmin abolished its anti-angiogenic activity and generated pro-angiogenic molecules. The fragmentation of CgA C-terminal region was increased also in murine models of PDAC. In these models, the inhibition of CgA fragmentation with aprotinin, an inhibitor of plasmin and other serine proteases, or the blockade of pro-angiogenic fragments with specific antibodies inhibited the growth of PDAC implanted subcutaneously in mice. Finally, administration of full-length CgA to mice bearing orthotopic PDAC reduced tumor perfusion, as measured by contrast-enhanced ultrasound. These findings suggest that PDAC can promote the cleavage of circulating CgA C-terminal region to generate fragments that regulate the tumor vascular biology and that may represent new potential therapeutic targets.

Establishment and Investigation of a Multiple Gene Expression Signature to Predict Long-Term Survival in Pancreatic Cancer

Pancreatic cancer remains a lethal type of cancer with poor prognosis. Molecular classification enables in-depth, precise prognostic assessment. This study is aimed at identifying a robust and simple mRNA signature to predict the overall survival (OS) of pancreatic cancer (PC) patients. Differentially expressed genes (DEGs) between 45 paired pancreatic tumor samples and adjacent healthy tissues were selected. For risk determination, a LASSO Cox regression model with DEGs was used to generate the OS-associated risk score formula for the training cohort containing 177 PC patients. Another five independent datasets were used as the testing cohort to determine the predictive efficiency for further validation. In total, 441 DEGs were selected after considering the enrichment of classical pathways, such as EMT, cell cycle, cell adhesion, and PI3K-AKT. A five-gene signature for risk discrimination was established with high efficacy using LASSO Cox regression in the training group. External validation showed that patients identified by the gene expression signature to be in the high-risk group had poorer prognosis compared with the low-risk patients. Further investigation identified the differential epigenetic modification patterns of the five genes, which indicated their roles in tumor progression and their effect on therapy. In conclusion, we constructed a robust five-gene expression signature that could predict the OS of PC patients, offering a new insight for risk discrimination in daily clinical practice.

Pancreatic neuroendocrine tumors: Therapeutic challenges and research limitations

Pancreatic neuroendocrine tumors (PNETs) are known to be the second most common epithelial malignancy of the pancreas. PNETs can be listed among the slowest growing as well as the fastest growing human cancers. The prevalence of PNETs is deceptively low; however, its incidence has significantly increased over the past decades. According to the American Cancer Society's estimate, about 4032 (> 7% of all pancreatic malignancies) individuals will be diagnosed with PNETs in 2020. PNETs often cause severe morbidity due to excessive secretion of hormones (such as serotonin) and/or overall tumor mass. Patients can live for many years (except for those patients with poorly differentiated G3 neuroendocrine tumors); thus, the prevalence of the tumors that is the number of patients actually dealing with the disease at any given time is fairly high because the survival is much longer than pancreatic ductal adenocarcinoma. Due to significant heterogeneity, the management of PNETs is very complex and remains an unmet clinical challenge. In terms of research studies, modest improvements have been made over the past decades in the identification of potential oncogenic drivers in order to enhance the quality of life and increase survival for this growing population of patients. Unfortunately, the majority of systematic therapies approved for the management of advanced stage PNETs lack objective response or at most result in modest benefits in survival. In this review, we aim to discuss the broad challenges associated with the management and the study of PNETs.

A Preoperative Clinical Risk Score Including C-Reactive Protein Predicts Histological Tumor Characteristics and Patient Survival after Surgery for Sporadic Non-Functional Pancreatic Neuroendocrine Neoplasms: An International Multicenter Cohort Study

Background: Oncological survival after resection of pancreatic neuroendocrine neoplasms (panNEN) is highly variable depending on various factors. Risk stratification with preoperatively available parameters could guide decision-making in multidisciplinary treatment concepts. C-reactive Protein (CRP) is linked to inferior survival in several malignancies. This study assesses CRP within a novel risk score predicting histology and outcome after surgery for sporadic non-functional panNENs. Methods: A retrospective multicenter study with national exploration and international validation. CRP and other factors associated with overall survival (OS) were evaluated by multivariable cox-regression to create a clinical risk score (CRS). Predictive values regarding OS, disease-specific survival (DSS), and recurrence-free survival (RFS) were assessed by time-dependent receiver-operating characteristics. Results: Overall, 364 patients were included. Median CRP was significantly higher in patients >60 years, G3, and large tumors. In multivariable analysis, CRP was the strongest preoperative factor for OS in both cohorts. In the combined cohort, CRP (cut-off ≥0.2 mg/dL; hazard-ratio (HR):3.87), metastases (HR:2.80), and primary tumor size ≥3.0 cm (HR:1.83) showed a significant association with OS. A CRS incorporating these variables was associated with postoperative histological grading, T category, nodal positivity, and 90-day morbidity/mortality. Time-dependent area-under-the-curve at 60 months for OS, DSS, and RFS was 69%, 77%, and 67%, respectively (all p < 0.001), and the inclusion of grading further improved the predictive potential (75%, 84%, and 78%, respectively). Conclusions: CRP is a significant marker of unfavorable oncological characteristics in panNENs. The proposed internationally validated CRS predicts histological features and patient survival.

Serum CNPY2 isoform 2 represents a novel biomarker for early detection of colorectal cancer

Since early diagnosis is very important for treating CRC, we decided to detect peripheral serum canopy fibroblast growth factor signaling regulator 2 (CNPY2) isoform 2 to verify its diagnostic value for CRC patients. Serum samples were collected from 430 CRC patients and 201 healthy controls. Enzyme-linked immunosorbent assay (ELISA) detection kits for CNPY2 isoform 2 were generated and then applied to measure serum CNPY2 isoform 2 concentrations. Serum carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) were also measured. The median serum CNPY2 isoform 2 concentrations in all CRC patients were significantly higher than those in the healthy control group (all P<0.001). Those with stage I CRC presented the highest area under the receiver operating characteristic curve (AUC) for CNPY2 isoform 2 [0.707, 95% confidence interval (CI): 0.649-0.765, P<0.001]. The diagnostic efficiency of the combination of CNPY2 isoform 2, CEA and CA19-9 was significantly higher than that of each biomarker detected separately (all P<0.0167). Serum CNPY2 isoform 2 may be a valuable biomarker for the early detection of CRC and presents an improvement in the diagnostic efficiency by combination of CEA and CA19-9.

Association between preoperative Vasostatin-1 and pathological features of aggressiveness in localized nonfunctioning pancreatic neuroendocrine tumors (NF-PanNET)

BACKGROUND

A reliable and accessible biomarker for nonfunctioning pancreatic neuroendocrine tumors (NF-PanNET) is currently unavailable. Chromogranin A (CgA) represents the best-described neuroendocrine biomarker, but its accuracy is low. Vasostatin-1 (VS-1), a fragment derived from the cleavage of CgA, was recently investigated and found to be more accurate as tumor biomarker in a cohort of patients affected by mainly metastatic small intestinal NET.

METHODS

Patients submitted to surgery for sporadic localized NF-PanNET at San Raffaele Hospital were included. Preoperative plasma samples were prospectively collected. Circulating levels of total-CgA and VS-1 were retrospectively investigated by sandwich Enzyme-Linked ImmunoSorbent Assays.

RESULTS

Overall, 50 patients were included. VS-1 value (P=0.0001) was the only preoperatively retrievable factor independently associated with NF-PanNET size. No significant correlation between CgA and tumor diameter was found (P = 0.057). A VS-1 value of 0.39 nM was identified as the optimal VS-1 cut-off accurately associated with NF-PanNET larger than 4 cm. Patients with VS-1 > 0.39 nM had a significantly higher frequency of microvascular invasion (P = 0.005) and nodal metastasis (P = 0.027). Median VS-1 plasma level was significantly higher in the presence of microvascular invasion (P = 0.001) and nodal metastasis (P = 0.012). PPI assumption significantly increased total-CgA levels, but not those of VS-1 (P = 0.111).

CONCLUSIONS

In localized, non-metastatic NF-PanNET, VS-1 is strongly associated to tumor dimension and its plasma levels are significantly higher in the presence of microvascular invasion and nodal metastases; moreover, VS-1 value is not affected by the PPI use.

Inhibitory effects of vasostatin-1 against atherogenesis

Vasostatin-1, a chromogranin A (CgA)-derived peptide (76 amino acids), is known to suppress vasoconstriction and angiogenesis. A recent study has shown that vasostatin-1 suppresses the adhesion of human U937 monocytes to human endothelial cells (HECs) via adhesion molecule down-regulation. The present study evaluated the expression of vasostatin-1 in human atherosclerotic lesions and its effects on inflammatory responses in HECs and human THP-1 monocyte-derived macrophages, macrophage foam cell formation, migration and proliferation of human aortic smooth muscle cells (HASMCs) and extracellular matrix (ECM) production by HASMCs, and atherogenesis in apolipoprotein E-deficient (ApoE^-/-) mice. Vasostatin-1 was expressed around Monckeberg's medial calcific sclerosis in human radial arteries. Vasostatin-1 suppressed lipopolysaccharide (LPS)-induced up-regulation of monocyte chemotactic protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in HECs. Vasostatin-1 suppressed inflammatory M1 phenotype and LPS-induced interleukin-6 (IL-6) secretion via nuclear factor-κB (NF-κB) down-regulation in macrophages. Vasostatin-1 suppressed oxidized low-density lipoprotein (oxLDL)-induced foam cell formation associated with acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) and CD36 down-regulation and ATP-binding cassette transporter A1 (ABCA1) up-regulation in macrophages. In HASMCs, vasostatin-1 suppressed angiotensin II (AngII)-induced migration and collagen-3 and fibronectin expression via decreasing ERK1/2 and p38 phosphorylation, but increased elastin expression and matrix metalloproteinase (MMP)-2 and MMP-9 activities via increasing Akt and JNK phosphorylation. Vasostatin-1 did not affect the proliferation and apoptosis in HASMCs. Four-week infusion of vasostatin-1 suppressed the development of aortic atherosclerotic lesions with reductions in intra-plaque inflammation, macrophage infiltration, and SMC content, and plasma glucose level in ApoE^-/- mice. These results indicate the inhibitory effects of vasostatin-1 against atherogenesis. The present study provided the first evidence that vasostatin-1 may serve as a novel therapeutic target for atherosclerosis.