Novel potential biomarkers for pancreatic cancer - A systematic review

The Role of Circulating Protein and Metabolite Biomarkers in the Development of Pancreatic Ductal Adenocarcinoma (PDAC): A Systematic Review and Meta-analysis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, and this is attributed to it being diagnosed at an advanced stage. Understanding the pathways involved in initial development may improve early detection strategies. This systematic review assessed the association between circulating protein and metabolite biomarkers and PDAC development.

METHODS

A literature search until August 2020 in MEDLINE, EMBASE, and Web of Science was performed. Studies were included if they assessed circulating blood, urine, or salivary biomarkers and their association with PDAC risk. Quality was assessed using the Newcastle-Ottawa scale for cohort studies. Random-effects meta-analyses were used to calculate pooled relative risk.

RESULTS

A total of 65 studies were included. Higher levels of glucose were found to be positively associated with risk of developing PDAC [n = 4 studies; pooled relative risk (RR): 1.61; 95% CI: 1.16-2.22]. Additionally, an inverse association was seen with pyridoxal 5'-phosphate (PLP) levels (n = 4 studies; RR: 0.62; 95% CI: 0.44-0.87). Meta-analyses showed no association between levels of C-peptide, members of the insulin growth factor signaling pathway, C-reactive protein, adiponectin, 25-hydroxyvitamin D, and folate/homocysteine and PDAC risk. Four individual studies also reported a suggestive positive association of branched-chain amino acids with PDAC risk, but due to differences in measures reported, a meta-analysis could not be performed.

CONCLUSIONS

Our pooled analysis demonstrates that higher serum glucose levels and lower levels of PLP are associated with risk of PDAC.

IMPACT

Glucose and PLP levels are associated with PDAC risk. More prospective studies are required to identify biomarkers for early detection.

Metagenomic analysis of gut microbiome reveals a dynamic change in Alistipes onderdonkii in the preclinical model of pancreatic cancer, suppressing its proliferation

Pancreatic cancer is a lethal cancer with aggressive and invasive characteristics. By the time it is diagnosed, patients already have tumors extended to other organs and show extremely low survival rates. The gut microbiome is known to be associated with many diseases and its imbalance affects the pathogenesis of pancreatic cancer. In this study, we established an orthotopic, patient-derived xenograft model to identify how the gut microbiome is linked to pancreatic ductal adenocarcinoma (PDAC). Using the 16S rDNA metagenomic sequencing, we revealed that the levels of Alistipes onderdonkii and Roseburia hominis decreased in the gut microbiome of the PDAC model. To explore the crosstalk between the two bacteria and PDAC cells, we collected the supernatant of the bacteria or cancer cell culture medium and treated it in a cross manner. While the cancer cell medium did not affect bacterial growth, we observed that the A. onderdonkii medium suppressed the growth of the pancreatic primary cancer cells. Using the bromodeoxyuridine/7-amino-actinomycin D (BrdU/7-AAD) staining assay, we confirmed that the A. onderdonkii medium inhibited the proliferation of the pancreatic primary cancer cells. Furthermore, RNA-seq analysis revealed that the A. onderdonkii medium induced unique transcriptomic alterations in the PDAC cells, compared to the normal pancreatic cells. Altogether, our data suggest that the reduction in the A. onderdonkii in the gut microbiome provides a proliferation advantage to the pancreatic cancer cells. KEY POINTS: • Metagenome analysis of pancreatic cancer model reveals A. onderdonkii downregulation. • A. onderdonkii culture supernatant suppressed the proliferation of pancreatic cancer cells. • RNA seq data reveals typical gene expression changes induced by A. onderdonkii.

The prognostic and predictive value of the albumin-bilirubin score in advanced pancreatic cancer

Albumin-bilirubin (ALBI) showed its prognostic and predictive value in hepatobiliary disease like hepatocellular carcinoma. However, little has been known about its role in pancreatic cancer.In this retrospective study, 149 patients with advanced pancreatic cancer (APC) treated in the Shanghai General Hospital from January 2009 to December 2014 were enrolled as the training cohort and 120 patients treated from January 2015 to December 2018 were taken as the validation cohort. We generated the ALBI score according previous studies. The correlations between ALBI and clinicopathological parameters were evaluated with the Pearson Chi-square test. Kaplan-Meier method and log-rank test were conducted to determine the correlation between ALBI and overall survival (OS). Then we used Cox regression model to investigate the prognostic significance of ALBI. We further assessed retrospectively whether ALBI score could be used to identify combination therapy candidates for APC.Eastern Cooperative Oncology Group Performance Status, hemoglobin, aspartate aminotransferase, and alanine aminotransferase were found to be significantly correlated with ALBI. Kaplan-Meier analysis showed that the median OS in patients with a pretreatment ALBI ≥-2.6 was 7.0 months, which was significantly shorter than OS of patients with a ALBI <-2.6 (13.0 months, P = .001). ALBI was independently correlated with OS in multivariate analysis. In the subgroup analysis, ALBI showed significant prognostic value in patients with liver metastasis but not those without liver metastasis in all 3 cohorts. In addition, only in the group with ALBI <-2.6, patients receiving combination therapy showed better prognosis than those receiving monotherapy.In conclusion, ALBI was a promising prognostic biomarker in APC with liver metastasis. ALBI also showed predictive value in identifying combination therapy candidates for patients with APC.

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.