ABSTRACT
Genomic instability of circulating tumor DNA (ctDNA) as a prognostic biomarker has not been evaluated in pancreatic cancer. We investigated the role of the genomic instability index of ctDNA in pancreatic ductal adenocarcinoma (PDAC). We prospectively enrolled 315 patients newly diagnosed with resectable (n = 110), locally advanced (n = 78), and metastatic (n = 127) PDAC from March 2015 through January 2020. Low-depth whole-genome cell-free DNA sequencing identified genome-wide copy number alterations using instability score (I-score) to reflect genome-wide instability. Plasma cell-free and matched tumor tissue DNA from 15 patients with resectable pancreatic cancer was sequenced to assess the concordance of chromosomal copy number alteration profiles. Associations of I-score with clinical factors or survival were assessed. Seventy-six patients had high genomic instability with I-score > 7.3 in pre-treatment ctDNA; proportions of high I-score were 5.5%, 5.1%, and 52% in resectable, locally advanced, and metastatic stages, respectively. Correlation coefficients between Z-scores of plasma and tissue DNA at segment resolution were high (r2 = 0.82). Univariable analysis showed the association of I-score with progression-free survival in each stage. Multivariable analyses demonstrated that clinical stage-adjusted I-scores were significant factors for progression-free and overall survival. In these patients, ctDNA genomic I-scores provided prognostic information relevant to progression-free survival in each clinical stage.
ABSTRACT
Angiogenesis is an essential step in cancer progression and metastasis. Changes in the microRNA (miRNA or miR) expression profiles of endothelial cells (ECs) elicited by cancer cells promote angiogenesis. Vascular endothelial growth factor (VEGF), a key pro-angiogenic factor, influences miRNA expression in ECs; however, the exact role that VEGF serves in miRNA regulation during angiogenesis is poorly defined. The present study aimed to demonstrate the differential angiogenic effects on human umbilical vein endothelial cells (HUVECs) of five different colorectal cancer (CRC) cell lines by in vitro HUVEC migration and angiogenesis assays in response to CRC-conditioned medium (CM). Among the tested CMs, LoVo was the most effective cell line in eliciting HUVEC angiogenic phenotypes, at least partially due to its high VEGF level. It was also observed that pro-angiogenesis-regulatory miRNAs (angio-miRNA) miR-296, miR-132, miR-105 and miR-200 were upregulated in the VEGF-rich LoVo CM compared with the VEGF-scarce SW620 CM. In addition, treatment with VEGF receptor 2 inhibitor downregulated the pro-angio-miRNAs, with the exception of miR-132, suggesting that VEGF, as well as additional signaling, is required for angio-miRNA expression. Quantitative analyses on pro-angio-miRNA target expression suggested that independent pathways may be involved in the regulation of their expression. Overall, the data from the present study indicated that multiple paracrine factors, including VEGF secreted by CRCs, effectively modulated angio-miRNA expression, thus impacting their target expression and the angiogenic phenotypes of HUVECs.
