Browsing by Author "Roy, Lynn"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    ARID3B increases ovarian tumor burden and is associated with a cancer stem cell gene signature
    (Impact Journals, 2014-09-30) Roy, Lynn; Samyesudhas, Serene J.; Carrasco, Martin; Joseph, Stancy; Dahl, Richard; Cowden Dahl, Karen D.; Biochemistry & Molecular Biology, School of Medicine
    Ovarian cancer is the most deadly gynecological malignancy since most patients have metastatic disease at the time of diagnosis. Therefore, identification of critical pathways that contribute to ovarian cancer progression is necessary to yield novel therapeutic targets. Recently we reported that the DNA binding protein ARID3B is overexpressed in human ovarian tumors. To determine if ARID3B has oncogenic functions in vivo, ovarian cancer cell lines stably expressing ARID3B were injected intraperitoneally into nude mice. Overexpression of ARID3B increased tumor burden and decreased survival. To assess how ARID3B contributes to the increased tumor growth in vivo, we identified ARID3B induced genes in tumor ascites cells. ARID3B induced expression of genes associated with metastasis and cancer stem cells (CD44, LGR5, PROM1 (CD133), and Notch2). Moreover, ARID3B increased the number of CD133+ (a cancer stem cell marker) cells compared to control cells. The increase in CD133+ cells resulting from ARID3B expression was accompanied by enhanced paclitaxel resistance. Our data demonstrate that ARID3B boosts production CD133+ cells and increases ovarian cancer progression in vivo.
  • Thumbnail Image
    Item
    Can Stemness and Chemoresistance Be Therapeutically Targeted via Signaling Pathways in Ovarian Cancer?
    (MDPI, 2018-07-24) Roy, Lynn; Cowden Dahl, Karen D.; Biochemistry and Molecular Biology, School of Medicine
    Ovarian cancer is the most lethal gynecological malignancy. Poor overall survival, particularly for patients with high grade serous (HGS) ovarian cancer, is often attributed to late stage at diagnosis and relapse following chemotherapy. HGS ovarian cancer is a heterogenous disease in that few genes are consistently mutated between patients. Additionally, HGS ovarian cancer is characterized by high genomic instability. For these reasons, personalized approaches may be necessary for effective treatment and cure. Understanding the molecular mechanisms that contribute to tumor metastasis and chemoresistance are essential to improve survival rates. One favored model for tumor metastasis and chemoresistance is the cancer stem cell (CSC) model. CSCs are cells with enhanced self-renewal properties that are enriched following chemotherapy. Elimination of this cell population is thought to be a mechanism to increase therapeutic response. Therefore, accurate identification of stem cell populations that are most clinically relevant is necessary. While many CSC identifiers (ALDH, OCT4, CD133, and side population) have been established, it is still not clear which population(s) will be most beneficial to target in patients. Therefore, there is a critical need to characterize CSCs with reliable markers and find their weaknesses that will make the CSCs amenable to therapy. Many signaling pathways are implicated for their roles in CSC initiation and maintenance. Therapeutically targeting pathways needed for CSC initiation or maintenance may be an effective way of treating HGS ovarian cancer patients. In conclusion, the prognosis for HGS ovarian cancer may be improved by combining CSC phenotyping with targeted therapies for pathways involved in CSC maintenance.
  • Thumbnail Image
    Item
    CD133 Promotes Adhesion to the Ovarian Cancer Metastatic Niche
    (Libertas Academica, 2018-04-09) Roy, Lynn; Bobbs, Alexander; Sattler, Rachel; Kurkewich, Jeffrey L; Dausinas, Paige B.; Nallathamby, Prakash; Cowden Dahl, Karen D.; Biochemistry and Molecular Biology, School of Medicine
    Cancer stem cells (CSCs) are an attractive therapeutic target due to their predicted role in both metastasis and chemoresistance. One of the most commonly agreed on markers for ovarian CSCs is the cell surface protein CD133. CD133+ ovarian CSCs have increased tumorigenicity, resistance to chemotherapy, and increased metastasis. Therefore, we were interested in defining how CD133 is regulated and whether it has a role in tumor metastasis. Previously we found that overexpression of the transcription factor, ARID3B, increased the expression of PROM1 (CD133 gene) in ovarian cancer cells in vitro and in xenograft tumors. We report that ARID3B directly regulates PROM1 expression. Importantly, in a xenograft mouse model of ovarian cancer, knockdown of PROM1 in cells expressing exogenous ARID3B resulted in increased survival time compared with cells expressing ARID3B and a control short hairpin RNA. This indicated that ARID3B regulation of PROM1 is critical for tumor growth. Moreover, we hypothesized that CD133 may affect metastatic spread. Given that the peritoneal mesothelium is a major site of ovarian cancer metastasis, we explored the role of PROM1 in mesothelial attachment. PROM1 expression increased adhesion to mesothelium in vitro and ex vivo. Collectively, our work demonstrates that ARID3B regulates PROM1 adhesion to the ovarian cancer metastatic niche.
  • Thumbnail Image
    Item
    In vivo tumor growth of high-grade serous ovarian cancer cell lines
    (Elsevier, 2015-08) Mitra, Anirban; Davis, David A.; Tomar, Sunil; Roy, Lynn; Gurler, Hilal; Xie, Jia; Lantvit, Daniel D.; Cardenas, Horacio; Fang, Fang; Liu, Yueying; Loughran, Elizabeth; Yang, Jing; Stack, M. Sharon; Emerson, Robert E.; Dahl, Karen D. Cowden; Barbolina, Maria; Nephew, Kenneth P.; Matei, Daniela; Burdette, Joanna E.; Department of Medicine, IU School of Medicine
    OBJECTIVE: Genomic studies of ovarian cancer (OC) cell lines frequently used in research revealed that these cells do not fully represent high-grade serous ovarian cancer (HGSOC), the most common OC histologic type. However, OC lines that appear to genomically resemble HGSOC have not been extensively used and their growth characteristics in murine xenografts are essentially unknown. METHODS: To better understand growth patterns and characteristics of HGSOC cell lines in vivo, CAOV3, COV362, KURAMOCHI, NIH-OVCAR3, OVCAR4, OVCAR5, OVCAR8, OVSAHO, OVKATE, SNU119 and UWB1.289 cells were assessed for tumor formation in nude mice. Cells were injected intraperitoneally (i.p.) or subcutaneously (s.c.) in female athymic nude mice and allowed to grow (maximum of 90 days) and tumor formation was analyzed. All tumors were sectioned and assessed using H&E staining and immunohistochemistry for p53, PAX8 and WT1 expression. RESULTS: Six lines (OVCAR3, OVCAR4, OVCAR5, OVCAR8, CAOV3, and OVSAHO) formed i.p xenografts with HGSOC histology. OVKATE and COV362 formed s.c. tumors only. Rapid tumor formation was observed for OVCAR3, OVCAR5 and OVCAR8, but only OVCAR8 reliably formed ascites. Tumors derived from OVCAR3, OVCAR4, and OVKATE displayed papillary features. Of the 11 lines examined, three (Kuramochi, SNU119 and UWB1.289) were non-tumorigenic. CONCLUSIONS: Our findings help further define which HGSOC cell models reliably generate tumors and/or ascites, critical information for preclinical drug development, validating in vitro findings, imaging and prevention studies by the OC research community.
  • Thumbnail Image
    Item
    Inspired to Learn: Integrating Pre-Clinical Respiratory Educational Principles into Clinical Clerkship Practice​
    (2023-04-28) Sharpe, Shannen; Friel, Rylee; Barron, Emily; Shockley, Emily; Thamba, Aish; Bontrager, Erin; Ganapaneni, Sruthri; Stoll, Kennedy; Vellutini, Natalie; Roy, Lynn; Cooper, Shannon; Kochhar, Komal; Carlos, Graham
    Introduction: IUSM students have reported on the Graduation Questionnaire (GQ) that there is a lack of pre-clinical content incorporated into clinical rotations. Student performance on respiratory/pulmonology questions on the USMLE Step 1 and 2 exams is similar to other medical disciplines at IUSM, despite feedback from students that the Pulmonary Grand Rounds (PGR) teaching method is very effective. Rather than presenting content via recorded didactic lectures, the PGR team, composed of a multidisciplinary physician panel, presents clinical vignettes in an interactive setting. Furthermore, according to student feedback, the current model lacks a sufficient content review of relevant Phase I material. Students have requested additional support with pre-clerkship study/review materials content. Through this study, we aim to empirically evaluate the impact of designing interactive pre-clerkship modules reviewing relevant Phase 1 PGR material on the medical knowledge and clinical competencies of Phase II students. Background: The American Medical Women’s Association organization called for scholarship pertaining to educational innovation. The PGR curriculum provides us with a unique opportunity to evaluate the impact of undergraduate medical education on student knowledge retention and engagement from a metacognition perspective. A diverse group of students and faculty was pulled together with the IUSM Research in Medical Education unit to creatively address the ability to quantify engagement and knowledge retention above in a scholarly project. PGR is a unique multi-modal teaching design built at a large medical school with nine campuses to increase student engagement via zoom, Top Hat, and a case-based teaching approach with a multidisciplinary panel. Study objective: Evaluate student engagement and knowledge retention through clerkship standardized examination performance, Step 2 performance, and GQ with the implementation of a spaced repetition learning model comprised of interactive pre-clerkship modules which reinforce session objectives introduced in pre-clinical education. Methods: In Phase I, PGR includes over 200 board-style questions throughout nine sessions. Students engage with the medical content by answering these questions on TopHat and discussing the reasoning for correct vs. Incorrect answers with the expert panel. Students are again tested over similar content during their local and NBME exams. We proposed the creation of an optional module for each clerkship for students to use prior to Phase II. The modules would include a question bank supplemented with videos to foster preparation and enhance performance on clinical clerkships and Step 2. This question bank would utilize the same questions students had originally seen in PGR months earlier to improve concept retention and memory. The instructional videos would connect physiology to the clinical scenarios the students expect to encounter during their clerkship. We would anonymously track student engagement through a pilot-tested survey and performance on the modules along with clerkship National Board of Medical Examiners exams, Step 2, and the GQ. Finally, we plan to assess knowledge gaps to supplement future grand rounds curriculum while providing clinically relevant information to improve patient care.
  • Thumbnail Image
    Item
    MiR-24 is required for hematopoietic differentiation of mouse embryonic stem cells
    (PLoS, 2015-01-29) Roy, Lynn; Bikorimana, Emmanuel; Lapid, Danica; Choi, Hyewon; Nguyen, Tan; Dahl, Richard; Department of Microbiology and Immunology, IU School of Medicine
    Overexpression of miRNA, miR-24, in mouse hematopoietic progenitors increases monocytic/ granulocytic differentiation and inhibits B cell development. To determine if endogenous miR-24 is required for hematopoiesis, we antagonized miR-24 in mouse embryonic stem cells (ESCs) and performed in vitro differentiations. Suppression of miR-24 resulted in an inability to produce blood and hematopoietic progenitors (HPCs) from ESCs. The phenotype is not a general defect in mesoderm production since we observe production of nascent mesoderm as well as mesoderm derived cardiac muscle and endothelial cells. Results from blast colony forming cell (BL-CFC) assays demonstrate that miR-24 is not required for generation of the hemangioblast, the mesoderm progenitor that gives rise to blood and endothelial cells. However, expression of the transcription factors Runx1 and Scl is greatly reduced, suggesting an impaired ability of the hemangioblast to differentiate. Lastly, we observed that known miR-24 target, Trib3, is upregulated in the miR-24 antagonized embryoid bodies (EBs). Overexpression of Trib3 alone in ESCs was able to decrease HPC production, though not as great as seen with miR-24 knockdown. These results demonstrate an essential role for miR-24 in the hematopoietic differentiation of ESCs. Although many miRNAs have been implicated in regulation of hematopoiesis, this is the first miRNA observed to be required for the specification of mammalian blood progenitors from early mesoderm.