Browsing by Author "Kwon, Jason J."
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Item Loss of miR-29a/b1 promotes inflammation and fibrosis in acute pancreatitis(American Society for Clinical Investigation, 2021-10-08) Dey, Shatovisha; Udari, Lata M.; RiveraHernandez, Primavera; Kwon, Jason J.; Willis, Brandon; Easler, Jeffrey J.; Fogel, Evan L.; Pandol, Stephen; Kota, Janaiah; Medical and Molecular Genetics, School of MedicineMicroRNA-29 (miR-29) is a critical regulator of fibroinflammatory processes in human diseases. In this study, we found a decrease in miR-29a in experimental and human chronic pancreatitis, leading us to investigate the regulatory role of the miR-29a/b1 cluster in acute pancreatitis (AP) utilizing a conditional miR-29a/b1–KO mouse model. miR-29a/b1-sufficient (WT) and -deficient (KO) mice were administered supramaximal caerulein to induce AP and characterized at different time points, utilizing an array of IHC and biochemical analyses for AP parameters. In caerulein-induced WT mice, miR-29a remained dramatically downregulated at injury. Despite high-inflammatory milieu, fibrosis, and parenchymal disarray in the WT mice during early AP, the pancreata fully restored during recovery. miR-29a/b1–KO mice showed significantly greater inflammation, lymphocyte infiltration, macrophage polarization, and ECM deposition, continuing until late recovery with persistent parenchymal disorganization. The increased pancreatic fibrosis was accompanied by enhanced TGFβ1 coupled with persistent αSMA+ PSC activation. Additionally, these mice exhibited higher circulating IL-6 and inflammation in lung parenchyma. Together, this collection of studies indicates that depletion of miR-29a/b1 cluster impacts the fibroinflammatory mechanisms of AP, resulting in (a) aggravated pathogenesis and (b) delayed recovery from the disease, suggesting a protective role of the molecule against AP.Item miR-29a Is Repressed by MYC in Pancreatic Cancer and Its Restoration Drives Tumor-Suppressive Effects via Downregulation of LOXL2(American Association for Cancer Research, 2020-02-01) Dey, Shatovisha; Kwon, Jason J.; Liu, Sheng; Hodge, Gabriel A.; Taleb, Solaema; Zimmers, Teresa A.; Wan, Jun; Kota, Janaiah; Medical and Molecular Genetics, School of MedicinePancreatic ductal adenocarcinoma (PDAC) is an intractable cancer with a dismal prognosis. MicroRNA-29a (miR-29a) is commonly downregulated in PDAC, however, mechanisms for its loss and role still remain unclear. Here we show that in PDAC, repression of miR-29a is directly mediated by MYC via promoter activity. RNA-seq analysis, integrated with miRNA target prediction, identified global miR-29a downstream targets in PDAC. Target enrichment coupled with gene ontology and survival correlation analyses identified the top five miR-29a downregulated target genes (LOXL2, MYBL2, CLDN1, HGK and NRAS) that are known to promote tumorigenic mechanisms. Functional validation confirmed that upregulation of miR-29a is sufficient to ablate translational expression of these five genes in PDAC. We show that the most promising target among the identified genes, LOXL2, is repressed by miR-29a via 3’-UTR binding. Pancreatic tissues from a PDAC murine model and patient biopsies showed overall high LOXL2 expression with inverse correlations with miR-29a levels. Collectively, our data delineate an anti-tumorigenic, regulatory role of miR-29a, and a novel MYC-miR-29a-LOXL2 regulatory axis in PDAC pathogenesis, indicating the potential of the molecule in therapeutic opportunities. Implications This study unravels a novel functional role of miR-29a in PDAC pathogenesis, and identifies a MYC-miR-29a-LOXL2 axis in regulation of the disease progression, implicating miR-29a as a potential therapeutic target for PDAC.Item Novel role of miR-29a in pancreatic cancer autophagy and its therapeutic potential(Impact Journals, 2016-11-01) Kwon, Jason J.; Willy, Jeffrey A.; Quirin, Kayla A.; Wek, Ronald C.; Korc, Murray; Yin, Xiao-Ming; Kota, Janaiah; Department of Medical & Molecular Genetics, IU School of MedicinePancreatic Ductal Adenocarcinoma (PDAC) is a highly lethal malignancy that responds poorly to current therapeutic modalities. In an effort to develop novel therapeutic strategies, we found downregulation of miR-29 in pancreatic cancer cells, and overexpression of miR-29a sensitized chemotherapeutic resistant pancreatic cancer cells to gemcitabine, reduced cancer cell viability, and increased cytotoxicity. Furthermore, miR-29a blocked autophagy flux, as evidenced by an accumulation of autophagosomes and autophagy markers, LC3B and p62, and a decrease in autophagosome-lysosome fusion. In addition, miR-29a decreased the expression of autophagy proteins, TFEB and ATG9A, which are critical for lysosomal function and autophagosome trafficking respectively. Knockdown of TFEB or ATG9A inhibited autophagy similar to miR-29a overexpression. Finally, miR-29a reduced cancer cell migration, invasion, and anchorage independent growth. Collectively, our findings indicate that miR-29a functions as a potent autophagy inhibitor, sensitizes cancer cells to gemcitabine, and decreases their invasive potential. Our data provides evidence for the use of miR-29a as a novel therapeutic agent to target PDAC.Item Pathophysiological role of microRNA-29 in pancreatic cancer stroma(Office of the Vice Chancellor for Research, 2015-04-17) Kwon, Jason J.; Nabinger, Sarah C.; Alluri, Ravi K.; Vega, Zachary; Sahu, Smiti S.; Abdul-Sater, Zahi; Yu, Zhangsheng; Gore, A. Jesse; Nalepa, Grzegorz; Saxena, Romil; Korc, Murray; Kota, JanaiahBackground: Dense fibrotic stroma associated with pancreatic ductal adenocarcinoma (PDAC) has been a major obstacle for drug delivery to the tumor bed and may impede attempts to slow down PDAC progression and metastasis. However, current antistromal drugs have not improved tumor response to chemotherapy or patient survival. Thus, a better understanding of the molecular mechanisms associated with tumorstromal interactions is desperately needed to develop novel anti-stromal therapeutic approaches. MicroRNAs (miRNAs) are an abundant class of highly conserved, small non-coding RNAs that function as key regulators of eukaryotic gene expression and cellular homeostasis. miR-29 is known to play a paramount role in the fibrotic process of several organs by providing crucial functions downstream of pro-fibrotic signaling pathways such as TGF-β1 and regulates the expression of extracellular matrix (ECM) proteins, a major component in the PDAC stroma. Upregulation of TGF-β1 is associated with PDAC pathogenesis and is known to activate stromal cells. Furthermore, vascular endothelial growth factor (VEGF) that stimulates tumor angiogenesis is a predicted target of miR-29. We hypothesize that miR-29 may be misregulated in TGF-β1 activated PDAC stromal cells and lead to excessive accumulation of ECM proteins and VEGF. Kwon et al. 2015 Annual AACR Meeting Restored expression of miR-29 could be therapeutically beneficial to modulate tumorstromal interactions. Methods: Northern blot or qPCR techniques were used to assess miR-29 levels in vitro stromal cells, murine PDAC model, and PDAC patient biopsies, and stromal deposition/fibrosis was determined by Sirius red staining. In murine and human PDAC samples, stromal specific miR-29 expression was determined via in situ hybridization by co-staining pancreatic tissues with glial fibrillary acidic protein a marker for stromal cells and miR-29. miR-29 functional studies were conducted by transfection of stroma cells with synthetic miR-29 mimics and locked nucleic acid, a miR-29 inhibitor, and ECM protein/VEGF expression was analyzed by western blot analysis. The effect of miR-29 overexpression in stromal cells on cancer colony growth was evaluated by direct coculture of stromal cells ectopically expressing miR-29 with pancreatic cancer cells, and subsequently, cancer colony number and stromal accumulation was determined by crystal violet and sirius red stains respectively. Results: In both in vitro and in vivo models as well as PDAC patient biopsies, we observed loss of miR-29 is a common phenomenon of activated stromal cells, and is associated with a significant increase in ECM and VEGF accumulation. Restored expression of miR-29 in stromal cells reduced the deposition of matrix proteins, VEGF expression, and cancer colony formation in direct co-culture. Conclusion: These results provide insight into the mechanistic role of miR-29 in PDAC stroma and its potential use as an anti-stromal/angiogenic therapeutic agent.Item Pathophysiological role of microRNA-29 in pancreatic cancer stroma(Nature Publishing Group, 2015-06-22) Kwon, Jason J.; Nabinger, Sarah C.; Vega, Zachary; Snigdha Sahu, Smiti; Alluri, Ravi K.; Abdul-Sater, Zahi; Yu, Zhangsheng; Gore, Jesse; Nalepa, Grzegorz; Saxena, Romil; Korc, Murray; Kota, Janaiah; Department of Medical & Molecular Genetics, IU School of MedicineDense fibrotic stroma associated with pancreatic ductal adenocarcinoma (PDAC) is a major obstacle for drug delivery to the tumor bed and plays a crucial role in pancreatic cancer progression. Current, anti-stromal therapies have failed to improve tumor response to chemotherapy and patient survival. Furthermore, recent studies show that stroma impedes tumor progression, and its complete ablation accelerates PDAC progression. In an effort to understand the molecular mechanisms associated with tumor-stromal interactions, using in vitro and in vivo models and PDAC patient biopsies, we show that the loss of miR-29 is a common phenomenon of activated pancreatic stellate cells (PSCs)/fibroblasts, the major stromal cells responsible for fibrotic stromal reaction. Loss of miR-29 is correlated with a significant increase in extracellular matrix (ECM) deposition, a major component in PDAC stroma. Our in vitro miR-29 gain/loss-of-function studies document the role of miR-29 in PSC-mediated ECM stromal protein accumulation. Overexpression of miR-29 in activated stellate cells reduced stromal deposition, cancer cell viability, and cancer growth in co-culture. Furthermore, the loss of miR-29 in TGF-β1 activated PSCs is SMAD3 dependent. These results provide insights into the mechanistic role of miR-29 in PDAC stroma and its potential use as a therapeutic agent to target PDAC.Item Safety and Efficacy of AAV Retrograde Pancreatic Ductal Gene Delivery in Normal and Pancreatic Cancer Mice(Elsevier, 2017-09-30) Quirin, Kayla A.; Kwon, Jason J.; Alioufi, Arafat; Factora, Tricia; Temm, Constance J.; Jacobsen, Max; Sandusky, George E.; Shontz, Kim; Chicoine, Louis G.; Clark, K. Reed; Mendell, Joshua T.; Korc, Murray; Kota, Janaiah; Medical and Molecular Genetics, School of MedicineRecombinant adeno-associated virus (rAAV)-mediated gene delivery shows promise to transduce the pancreas, but safety/efficacy in a neoplastic context is not well established. To identify an ideal AAV serotype, route, and vector dose and assess safety, we have investigated the use of three AAV serotypes (6, 8, and 9) expressing GFP in a self-complementary (sc) AAV vector under an EF1α promoter (scAAV.GFP) following systemic or retrograde pancreatic intraductal delivery. Systemic delivery of scAAV9.GFP transduced the pancreas with high efficiency, but gene expression did not exceed >45% with the highest dose, 5 × 1012 viral genomes (vg). Intraductal delivery of 1 × 1011 vg scAAV6.GFP transduced acini, ductal cells, and islet cells with >50%, ∼48%, and >80% efficiency, respectively, and >80% pancreatic transduction was achieved with 5 × 1011 vg. In a KrasG12D-driven pancreatic cancer mouse model, intraductal delivery of scAAV6.GFP targeted acini, epithelial, and stromal cells and exhibited persistent gene expression 5 months post-delivery. In normal mice, intraductal delivery induced a transient increase in serum amylase/lipase that resolved within a day of infusion with no sustained pancreatic inflammation or fibrosis. Similarly, in PDAC mice, intraductal delivery did not increase pancreatic intraepithelial neoplasia progression/fibrosis. Our study demonstrates that scAAV6 targets the pancreas/neoplasm efficiently and safely via retrograde pancreatic intraductal delivery.Item A Systematic Review of miR-29 in Cancer(Elsevier, 2018-12-31) Kwon, Jason J.; Factora, Tricia D.; Dey, Shatovisha; Kota, Janaiah; Medical and Molecular Genetics, School of MedicineMicroRNAs (miRNA) are small non-coding RNAs (∼22 nt in length) that are known as potent master regulators of eukaryotic gene expression. miRNAs have been shown to play a critical role in cancer pathogenesis, and the misregulation of miRNAs is a well-known feature of cancer. In recent years, miR-29 has emerged as a critical miRNA in various cancers, and it has been shown to regulate multiple oncogenic processes, including epigenetics, proteostasis, metabolism, proliferation, apoptosis, metastasis, fibrosis, angiogenesis, and immunomodulation. Although miR-29 has been thoroughly documented as a tumor suppressor in the majority of studies, some controversy remains with conflicting reports of miR-29 as an oncogene. In this review, we provide a systematic overview of miR-29's functional role in various mechanisms of cancer and introspection on the contradictory roles of miR-29.