Browsing by Author "Cowden Dahl, Karen D."

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    ARID3A and ARID3B induce stem promoting pathways in ovarian cancer cells
    (Elsevier, 2020-05-15) Dausinas, Paige; Pulakanti, Kirthi; Rao, Sridhar; Cole, Jennifer M.; Dahl, Richard; Cowden Dahl, Karen D.; Biochemistry and Molecular Biology, School of Medicine
    ARID3A and ARID3B are paralogs from the AT-Rich interactive Domain (ARID) family. ARID3A and ARID3B associate to regulate genes in B-cells and cancer. We were the first to demonstrate that ARID3B regulates stem cell genes and promotes the cancer stem cell phenotype. Importantly, different knockout phenotypes in mice and distinct patterns of expression in adult animals suggests that ARID3A and ARID3B may have unique functions. In addition, high levels of ARID3B but not ARID3A induce cell death. Our goal was to express ARID3A, ARID3B, or both genes at a moderate level (as can be observed in cancer) and then identify ARID3 regulated genes. We transduced ovarian cancer cells with ARID3A-GFP, ARID3B-RFP, or both. RNA-sequencing was conducted. ARID3A and ARID3B regulated nearly identical sets of genes. Few genes (<5%) were uniquely regulated by ARID3A or ARID3B. ARID3A/B induced genes involved in cancer and stem cell processes including: Twist, MYCN, MMP2, GLI2, TIMP3, and WNT5B. We found that ARID3A and ARID3B also induced expression of each other, providing evidence of the cooperativity. While ARID3A and ARID3B likely have unique functions in distinct contexts, they are largely capable of regulating the same stem cell genes in cancer cells. This study provides a comprehensive list of genes and pathways regulated by ARID3A and ARID3B in ovarian cancer cells.
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    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.
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    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.
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    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.
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    MAPK Signaling Is Required for Generation of Tunneling Nanotube-Like Structures in Ovarian Cancer Cells
    (MDPI, 2021-01-13) Cole, Jennifer M.; Dahl, Richard; Cowden Dahl, Karen D.; Microbiology and Immunology, School of Medicine
    Ovarian cancer (OC) cells survive in the peritoneal cavity in a complex microenvironment composed of diverse cell types. The interaction between tumor cells and non-malignant cells is crucial to the success of the metastatic process. Macrophages activate pro-metastatic signaling pathways in ovarian cancer cells (OCCs), induce tumor angiogenesis, and orchestrate a tumor suppressive immune response by releasing anti-inflammatory cytokines. Understanding the interaction between immune cells and tumor cells will enhance our ability to combat tumor growth and dissemination. When co-cultured with OCCs, macrophages induce projections consistent with tunneling nanotubes (TnTs) to form between OCCs. TnTs mediate transfer of material between cells, thus promoting invasiveness, angiogenesis, proliferation, and/or therapy resistance. Macrophage induction of OCC TnTs occurs through a soluble mediator as macrophage-conditioned media potently induced TnT formation in OCCs. Additionally, EGFR-induced TnT formation in OCCs through MAPK signaling may occur. In particular, inhibition of ERK and RSK prevented EGFR-induced TnTs. TnT formation in response to macrophage-conditioned media or EGFR signaling required MAPK signaling. Collectively, these studies suggest that inhibition of ERK/RSK activity may dampen macrophage-OCC communication and be a promising therapeutic strategy.
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    The miR-23a∼27a∼24-2 microRNA Cluster Promotes Inflammatory Polarization of Macrophages
    (The American Association of Immunologists, 2021) Boucher, Austin; Klopfenstein, Nathan; Hallas, William Morgan; Skibbe, Jennifer; Appert, Andrew; Jang, Seok Hee; Pulakanti, Kirthi; Rao, Sridhar; Cowden Dahl, Karen D.; Dahl, Richard; Microbiology and Immunology, School of Medicine
    Macrophages are critical for regulating inflammatory responses. Environmental signals polarize macrophages to either a pro-inflammatory (M1) state or an anti-inflammatory (M2) state. We observed that the microRNA cluster mirn23a, coding for miRs-23a~27a~24–2, regulates mouse macrophage polarization. Gene expression analysis of mirn23a deficient myeloid progenitors revealed a decrease in Toll like receptor and interferon signaling. Mirn23a−/− bone marrow derived macrophages (BMDMs) have an attenuated response to lipopolysaccharide (LPS) demonstrating an anti-inflammatory phenotype in mature cells. In vitro, mirn23a−/− BMDMs have decreased M1 responses and an enhanced M2 responses. Overexpression of mirn23a has the opposite effect enhancing M1 and inhibiting M2 gene expression. Interestingly expression of mirn23a miRNAs goes down with inflammatory stimulation and up with anti-inflammatory stimulation suggesting that its regulation prevents locking macrophages into polarized states. M2 polarization of tumor associated macrophages (TAMs) correlates with poor outcome for many tumors, so to determine if there was a functional consequence of mirn23a loss modulating immune cell polarization we assayed syngeneic tumor growth in wildtype and mirn23a−/− mice. Consistent with the increased anti-inflammatory/ immunosuppressive phenotype in vitro, mirn23a−/− mice inoculated with syngeneic tumor cells had worse outcomes compared to wildtype mice. Co-injecting tumor cells with mirn23a−/− BMDMs into wildtype mice phenocopied tumor growth in mirn23a−/− mice supporting a critical role for mirn23a miRNAs in macrophage mediated tumor immunity. Our data demonstrates that mirn23a regulates M1/M2 polarization and suggests that manipulation of mirn23a miRNA can be used to direct macrophage polarization to drive a desired immune response.