Global targetome analysis reveals critical role of miR-29a in pancreatic stellate cell mediated regulation of PDAC tumor microenvironment

Abstract

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive forms of malignancies with a nearly equal incidence and mortality rates in patients. Pancreatic stellate cells (PSCs) are critical players in PDAC microenvironment to promote the aggressiveness and pathogenesis of the disease. Dysregulation of microRNAs (miRNAs) have been shown to play a significant role in progression of PDAC. Earlier, we observed a PSC-specific downregulation of miR-29a in PDAC pancreas, however, the mechanism of action of the molecule in PSCs is still to be elucidated. The current study aims to clarify the regulation of miR-29a in PSCs and identifies functionally important downstream targets that contribute to tumorigenic activities during PDAC progression. Methods: In this study, using RNAseq approach, we performed transcriptome analysis of paired miR-29a overexpressing and control human PSCs (hPSCs). Enrichment analysis was performed with the identified differentially expressed genes (DEGs). miR-29a targets in the dataset were identified, which were utilized to create network interactions. Western blots were performed with the top miR-29a candidate targets in hPSCs transfected with miR-29a mimic or scramble control. Results: RNAseq analysis identified 202 differentially expressed genes, which included 19 downregulated direct miR-29a targets. Translational repression of eight key pro-tumorigenic and-fibrotic targets namely IGF-1, COL5A3, CLDN1, E2F7, MYBL2, ITGA6 and ADAMTS2 by miR-29a was observed in PSCs. Using pathway analysis, we find that miR-29a modulates effectors of IGF-1-p53 signaling in PSCs that may hinder carcinogenesis. We further observe a regulatory role of the molecule in pathways associated with PDAC ECM remodeling and tumor-stromal crosstalk, such as INS/IGF-1, RAS/MAPK, laminin interactions and collagen biosynthesis.

Loss of miR-29a/b1 promotes inflammation and fibrosis in acute pancreatitis

“…The current study investigated the impact of the miR-29a/b1 cluster on pancreas injury and regeneration during AP, utilizing a potentially novel conditional miR-29a/b1–KO mouse model. miR-29 plays a crucial role in fibrosis and ECM remodeling under diverse pathophysiological conditions, including that in the pancreas ( 8 , 21 , 38 , 39 ). However, it is not known whether miR-29 regulates the fibroinflammatory mechanisms of AP.…”

“…Excess and continued deposition of ECM proteins such as collagen and fibronectin resulted in a significant delay in AP recovery in the KO mice. miR-29a directly targets several essential fibrillar and nonfibrillar ECM proteins associated with tissue maintenance and pancreas remodeling, thereby alleviating fibrogenesis ( 11 , 21 , 39 ). The dramatic and sustained increase in matrix deposition in the KO AP mice may be indicative of a direct miR-29 regulation of its ECM targets.…”

Identification of DDX31 as a Potential Oncogene of Invasive Metastasis and Proliferation in PDAC

“…Part of these genes have been reported in basic studies of pancreatic cancer and are closely related to the invasion and metastasis of pancreatic cancer according to the literature, including MYC ( Sodir et al, 2020 ), CDH2 ( Shintani et al, 2008 ), SNAI1 ( Dai et al, 2017 ), YAP1, SOX2 ( Zhang et al, 2017 ). Besides, these genes, ADAMTS2 ( Dey et al, 2020 ), KRT9 ( Andolino et al, 2018 ), KRT13 ( Nguyen et al, 2021 ), LY6D ( Barros-Silva et al, 2018 ), had been reported in a variety of cancers. GO enrichment analysis ( Table 1 ) was performed on the intersections.…”

miRNA‑7515 suppresses pancreatic cancer cell proliferation, migration and invasion via downregulating IGF‑1 expression

“…Accumulating evidence indicates that IGF-related signaling pathways promote the progression of PC to an advanced stage via stimulating the proliferation, metastasis and chemoresistance of PC cells (27). IGF-1 is a member of IGF family, and previous studies have demonstrated that the expression levels of IGF-1 were upregulated in PC tissues, which indicates its potential as a diagnostic biomarker in PC (28,29).…”