Pancreatic 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.

Recombinant 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.

Advanced paternal age (APA) has no formal definition, though many publications utilize the cutoff of fathers >40 years of age. The literature demonstrates an association between APA and certain conditions including de novo autosomal dominant disorders, birth defects, and neuropsychiatric conditions. This study surveyed 165 genetic counselors within the National Society of Genetic Counselors to assess their current approach to APA. t Tests, analysis of variance, logistic regression, and chi‐squared tests were performed on quantitative data, and content analysis was applied to qualitative data. Although most respondents have discussed APA with a patient (88%), there was no consensus on what age cutoff constitutes APA: >40 (N = 53, 37.9%), >45 (N = 61, 43.6%), >50 (N = 24, 17.1%), or >55 (N = 2, 1.4%). Those who discussed APA were more likely to be prenatal counselors, see more patients per week, be board certified, or be familiar with current APA guidelines. Respondents agreed the literature supports the association of APA with deleterious outcomes (mean agreement = 8.2, median = 8 on a 1 = strongly disagree to 10 = strongly agree). Individuals who discussed APA and were board certified had higher agreement. Content analysis confirmed agreement that the literature supports an association between APA and deleterious outcomes (documented in responses from 31.5% of prenatal respondents, 17.8% others) but noted that available testing and screening options for associated conditions are limited (34.4% of prenatal respondents, 17.4% others). Prenatal and non‐prenatal respondents reported similar agreement with the statement that APA is associated with deleterious outcomes. However, most non‐prenatal respondents were unfamiliar with current guidelines (80%), and presumably as a result, were also less likely to discuss APA with their patients. Our study identified a need to disseminate information regarding APA and current guidelines to genetic counselors, particularly non‐prenatal and those with less experience.

Pancreatic ductal adenocarcinoma (PDAC) still remains to be one of the most highly malignant human diseases and is resistant to the majority of current therapeutic modalities. Oncogene MYC has been known to be upregulated in PDAC and plays a key role in carcinogenesis and tumor progression. In our previous work, we found the downregulation of miR-29 is a common phenomenon of PDAC, and its restored expression reduced cancer cell migration/invasive potential, anchorage independent growth, and sensitized them to gemcitabine. Furthermore, we showed that miR-29 blocks autophagy in cancer cells by targeting key autophagy related proteins. However, the mechanism associated with the loss of miR-29 in PDAC has yet to be elucidated. Here we demonstrate that MYC inhibits miR-29 expression in PDAC. MYC nuclear localization negatively correlates with miR-29 expression in various pancreatic cancer cell lines, and knockdown of MYC led to an increased expression of both primary miR-29a/b1 transcript and mature miR-29a. Furthermore, miR-29 overexpression in combination with gemcitabine led to decreased cancer cell viability and increased intracellular reactive oxygen species (ROS) and cell death. Our findings show for the first time that MYC represses miR-29 in PDAC, and miR-29 sensitizes pancreatic cancer cells to gemcitabine through increased intracellular ROS. Taken together our results, indicating the potential use of miR-29a as a novel therapeutic agent for PDAC. Citation Format: Jason J. Kwon, Kayla Quirin, Arafat Aljoufi, Amira Nafiseh, Janaiah Kota. Restoration of MYC-repressed miR-29 in pancreatic cancer cells leads to increased reactive oxygen species and gemcitabine sensitization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-327. doi:10.1158/1538-7445.AM2017-LB-327