IU Indianapolis ScholarWorks :: Browsing by Subject "Transcription factor"

Browsing by Subject "Transcription factor"

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Applying Small Molecule Signal Transducer and Activator of Transcription-3 (STAT3) Protein Inhibitors as Pancreatic Cancer Therapeutics
(American Association for Cancer Research, 2016-05) Arpin, Carolynn C.; Mac, Stephen; Jiang, Yanlin; Cheng, Huiwen; Grimard, Michelle; Page, Brent D. G.; Kamocka, Malgorzata M.; Haftchenary, Sina; Su, Han; Ball, Daniel; Rosa, David A.; Lai, Ping-Shan; Gómez-Biagi, Rodolfo F.; Ali, Ahmed M.; Rana, Rahul; Hanenberg, Helmut; Kerman, Kagan; McElyea, Kyle C.; Sandusky, George E.; Gunning, Patrick T.; Fishel, Melissa L.; Pediatrics, School of Medicine
Constitutively activated STAT3 protein has been found to be a key regulator of pancreatic cancer and a target for molecular therapeutic intervention. In this study, PG-S3-001, a small molecule derived from the SH-4-54 class of STAT3 inhibitors, was found to inhibit patient-derived pancreatic cancer cell proliferation in vitro and in vivo in the low micromolar range. PG-S3-001 binds the STAT3 protein potently, Kd = 324 nmol/L by surface plasmon resonance, and showed no effect in a kinome screen (>100 cancer-relevant kinases). In vitro studies demonstrated potent cell killing as well as inhibition of STAT3 activation in pancreatic cancer cells. To better model the tumor and its microenvironment, we utilized three-dimensional (3D) cultures of patient-derived pancreatic cancer cells in the absence and presence of cancer-associated fibroblasts (CAF). In this coculture model, inhibition of tumor growth is maintained following STAT3 inhibition in the presence of CAFs. Confocal microscopy was used to verify tumor cell death following treatment of 3D cocultures with PG-S3-001. The 3D model was predictive of in vivo efficacy as significant tumor growth inhibition was observed upon administration of PG-S3-001. These studies showed that the inhibition of STAT3 was able to impact the survival of tumor cells in a relevant 3D model, as well as in a xenograft model using patient-derived cells.
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.
Attraction and Compaction of Migratory Breast Cancer Cells by Bone Matrix Proteins through Tumor-Osteocyte Interactions
(Nature Publishing Group, 2018-04-03) Chen, Andy; Wang, Luqi; Liu, Shengzhi; Wang, Yue; Liu, Yunlong; Wang, Mu; Nakshatri, Harikrishna; Li, Bai-Yan; Yokota, Hiroki; Biomedical Engineering, School of Engineering and Technology
Bone is a frequent site of metastasis from breast cancer. To understand the potential role of osteocytes in bone metastasis, we investigated tumor-osteocyte interactions using two cell lines derived from the MDA-MB-231 breast cancer cells, primary breast cancer cells, and MLO-A5/MLO-Y4 osteocyte cells. When three-dimensional (3D) tumor spheroids were grown with osteocyte spheroids, tumor spheroids fused with osteocyte spheroids and shrank. This size reduction was also observed when tumor spheroids were exposed to conditioned medium isolated from osteocyte cells. Mass spectrometry-based analysis predicted that several bone matrix proteins (e.g., collagen, biglycan) in conditioned medium could be responsible for tumor shrinkage. The osteocyte-driven shrinkage was mimicked by type I collagen, the most abundant organic component in bone, but not by hydroxyapatite, a major inorganic component in bone. RNA and protein expression analysis revealed that tumor-osteocyte interactions downregulated Snail, a transcription factor involved in epithelial-to-mesenchymal transition (EMT). An agarose bead assay showed that bone matrix proteins act as a tumor attractant. Collectively, the study herein demonstrates that osteocytes attract and compact migratory breast cancer cells through bone matrix proteins, suppress tumor migration, by Snail downregulation, and promote subsequent metastatic colonization.
AZI23'UTR Is a New SLC6A3 Downregulator Associated with an Epistatic Protection Against Substance Use Disorders
(Springer Nature, 2018-07) Liu, Kefu; Yu, Jinlong; Zhao, Juan; Zhou, Yanhong; Xiong, Nian; Xu, Jie; Wang, Tao; Bell, Richard L.; Qing, Hong; Lin, Zhicheng; Psychiatry, School of Medicine
Regulated activity of SLC6A3, which encodes the human dopamine transporter (DAT), contributes to diseases such as substance abuse disorders (SUDs); however, the exact transcription mechanism remains poorly understood. Here, we used a common genetic variant of the gene, intron 1 DNP1B sequence, as bait to screen and clone a new transcriptional activity, AZI23'UTR, for SLC6A3. AZI23'UTR is a 3' untranslated region (3'UTR) of the human 5-Azacytidine Induced 2 gene (AZI2) but appeared to be transcribed independently of AZI2. Found to be present in both human cell nuclei and dopamine neurons, this RNA was shown to downregulate promoter activity through a variant-dependent mechanism in vitro. Both reduced RNA density ratio of AZI23'UTR/AZI2 and increased DAT mRNA levels were found in ethanol-naive alcohol-preferring rats. Secondary analysis of dbGaP GWAS datasets (Genome-Wide Association Studies based on the database of Genotypes and Phenotypes) revealed significant interactions between regions upstream of AZI23'UTR and SLC6A3 in SUDs. Jointly, our data suggest that AZI23'UTR confers variant-dependent transcriptional regulation of SLC6A3, a potential risk factor for SUDs.
Bcl6 is a subset-defining transcription factor of lymphoid tissue inducer-like ILC3
(Cell Press, 2023) Tachó-Piñot, Roser; Stamper, Christopher T.; King, James I.; Matei-Rascu, Veronika; Richardson, Erin; Li, Zhi; Roberts, Luke B.; Bassett, John W.; Melo-Gonzalez, Felipe; Fiancette, Rémi; Lin, I-Hsuan; Dent, Alexander; Harada, Yohsuke; Finlay, Conor; Mjösberg, Jenny; Withers, David R.; Hepworth, Matthew R.; Microbiology and Immunology, School of Medicine
Innate lymphoid cells (ILCs) are tissue-resident effector cells with roles in tissue homeostasis, protective immunity, and inflammatory disease. Group 3 ILCs (ILC3s) are classically defined by the master transcription factor RORγt. However, ILC3 can be further subdivided into subsets that share type 3 effector modules that exhibit significant ontological, transcriptional, phenotypic, and functional heterogeneity. Notably lymphoid tissue inducer (LTi)-like ILC3s mediate effector functions not typically associated with other RORγt-expressing lymphocytes, suggesting that additional transcription factors contribute to dictate ILC3 subset phenotypes. Here, we identify Bcl6 as a subset-defining transcription factor of LTi-like ILC3s in mice and humans. Deletion of Bcl6 results in dysregulation of the LTi-like ILC3 transcriptional program and markedly enhances expression of interleukin-17A (IL-17A) and IL-17F in LTi-like ILC3s in a manner in part dependent upon the commensal microbiota-and associated with worsened inflammation in a model of colitis. Together, these findings redefine our understanding of ILC3 subset biology.
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.
The Chd4 subunit of the NuRD complex regulates Pdx1-controlled genes involved in β-cell function
(Bioscientifica, 2022-06-14) Davidson, Rebecca K.; Weaver, Staci A.; Casey, Nolan; Kanojia, Sukrati; Hogarth, Elise; Schneider Aguirre, Rebecca; Sims, Emily K.; Evans-Molina, Carmella; Spaeth, Jason M.; Biochemistry and Molecular Biology, School of Medicine
Type 2 diabetes (T2D) is associated with loss of transcription factors (TFs) from a subset of failing β-cells. Among these TFs is Pdx1, which controls the expression of numerous genes involved in maintaining β-cell function and identity. Pdx1 activity is modulated by transcriptional coregulators and has recently been shown, through an unbiased screen, to interact with the Chd4 ATPase subunit of the nucleosome remodeling and deacetylase complex. Chd4 contributes to the maintenance of cellular identity and functional status of numerous different cell types. Here, we demonstrated that Pdx1 dynamically interacts with Chd4 under physiological and stimulatory conditions within islet β-cells and established a fundamental role for Chd4 in regulating insulin secretion and modulating numerous Pdx1-bound genes in vitro, including the MafA TF, where we discovered Chd4 is bound to the MafA region 3 enhancer. Furthermore, we found that Pdx1:Chd4 interactions are significantly compromised in islet β-cells under metabolically induced stress in vivo and in human donor tissues with T2D. Our findings establish a fundamental role for Chd4 in regulating insulin secretion and modulating Pdx1-bound genes in vitro, and disruption of Pdx1:Chd4 interactions coincides with β-cell dysfunction associated with T2D.
Chx10+V2a interneurons in spinal motor regulation and spinal cord injury
(Wolters Kluwer, 2023) Li, Wen-Yuan; Deng, Ling-Xiao; Zhai, Feng-Guo; Wang, Xiao-Yu; Li, Zhi-Gang; Wang, Ying; Neurological Surgery, School of Medicine
Chx10-expressing V2a (Chx10+V2a) spinal interneurons play a large role in the excitatory drive of motoneurons. Chemogenetic ablation studies have demonstrated the essential nature of Chx10+V2a interneurons in the regulation of locomotor initiation, maintenance, alternation, speed, and rhythmicity. The role of Chx10+V2a interneurons in locomotion and autonomic nervous system regulation is thought to be robust, but their precise role in spinal motor regulation and spinal cord injury have not been fully explored. The present paper reviews the origin, characteristics, and functional roles of Chx10+V2a interneurons with an emphasis on their involvement in the pathogenesis of spinal cord injury. The diverse functional properties of these cells have only been substantiated by and are due in large part to their integration in a variety of diverse spinal circuits. Chx10+V2a interneurons play an integral role in conferring locomotion, which integrates various corticospinal, mechanosensory, and interneuron pathways. Moreover, accumulating evidence suggests that Chx10+V2a interneurons also play an important role in rhythmic patterning maintenance, left-right alternation of central pattern generation, and locomotor pattern generation in higher order mammals, likely conferring complex locomotion. Consequently, the latest research has focused on postinjury transplantation and noninvasive stimulation of Chx10+V2a interneurons as a therapeutic strategy, particularly in spinal cord injury. Finally, we review the latest preclinical study advances in laboratory derivation and stimulation/transplantation of these cells as a strategy for the treatment of spinal cord injury. The evidence supports that the Chx10+V2a interneurons act as a new therapeutic target for spinal cord injury. Future optimization strategies should focus on the viability, maturity, and functional integration of Chx10+V2a interneurons transplanted in spinal cord injury foci.
Combating PDAC Drug Resistance: The Role of Ref-1 Inhibitors in Accelerating Progress in Pancreatic Cancer Research
(Elsevier, 2024) Kpenu, Eyram K.; Kelley, Mark R.; Pediatrics, School of Medicine
Pancreatic Ductal Adenocarcinoma (PDAC) remains one of the most lethal solid tumor diagnoses given its limited treatment options and dismal prognosis. Its complex tumor microenvironment (TME), heterogeneity, and high propensity for drug resistance are major obstacles in developing effective therapies. Here, we highlight the critical role of Redox effector 1 (Ref-1) in PDAC progression and drug resistance, focusing on its redox regulation of key transcription factors (TFs) such as STAT3, HIF1α, and NF-κB, which are pivotal for tumor survival, proliferation, and immune evasion. We discuss the development of novel Ref-1 inhibitors, including second-generation compounds with enhanced potency and improved pharmacokinetic profiles, which have shown significant promise in preclinical models. These inhibitors disrupt Ref-1’s redox function, leading to decreased TF activity and increased chemosensitivity in PDAC cells. We further detail our utilization of advanced preclinical models, such as 3D spheroids, organoids, and Tumor-Microenvironment-on-Chip (T-MOC) systems, which better simulate the complex conditions of the PDAC TME and improve the predictive power of therapeutic responses. By targeting Ref-1 and its associated pathways, in conjunction with improved models, more replicative of PDAC’s TME, we are focused on approaches which hold the potential to overcome current therapeutic limitations and advance the development of more effective treatments for PDAC. Our findings suggest that integrating Ref-1 inhibitors into combination therapies could disrupt multiple survival mechanisms within the tumor, offering new hope for improving outcomes in this challenging cancer.
The Contribution of Pdx1-Bound Chromatin Remodelers in Controlling β-Cell Differentiation and Function
(2022-12) Davidson, Rebecca Kelly; Spaeth, Jason; Evans-Molina, Carmella; Mosley, Amber; Mastracci, Teresa; Balakrishnan, Lata
Understanding β-cell development and function is essential for generating more effective treatment options for individuals with diabetes. A key player in pancreatogenesis, islet development, and mature β-cell function is the Pdx1 transcription factor (TF). Pdx1 activity is modulated through interactions with various coregulators, including the Swi/Snf chromatin remodeling and Nucleosome Remodeling and Deacetylase (NuRD) complexes. Loss of one Swi/Snf ATPase subunit, Brg1, in early pancreatogenesis reduces final pancreas mass, and β-cell-specific deletion of both subunits, Brg1 and Brm, leads to glucose intolerance and loss of insulin production in the β-cell. Here, we hypothesized Swi/Snf governs endocrine progenitor cell development and postnatal islet function. To test this, we generated conditional murine knockouts of Brg1 (Brg1Δendo;Brm+/-), Brm (Brg1Δendo/+;Brm-/-), or both subunits (DKOΔendo) during endocrine cell development. No DKOΔendo mice were recovered at weaning, and loss of Brg1 but not Brm led to severe glucose intolerance, ad-lib fed hyperglycemia, and reduced insulin levels by four weeks of age. Brg1Δendo;Brm+/- mice had fewer islets and compromised insulin secretion. Together, these data suggest that loss of Brg1 during endocrine cell development has negative impacts on postnatal islet function, with loss of both Brg1 and Brm being early postnatal lethal. Pdx1 has been shown to also interact with the Chd4 helicase subunit of the NuRD complex. Here, we demonstrate Pdx1:Chd4 interactions are increased under stimulatory conditions and hypothesize that Chd4 modulates expression of Pdx1-bound genes critical for β-cell function. To test this, we generated a tamoxifen inducible, β-cell-specific Chd4 knockout mouse model (Chd4Δβ). Four weeks following Chd4 removal, Chd4Δβ mutants were glucose intolerant with severe insulin secretion defects. Additionally, Chd4Δβ islets contained fewer mature insulin granules and secreted more proinsulin. RNA-sequencing from Chd4Δβ β-cells identified numerous upregulated (eg Hk2, Mycl) and downregulated genes (eg MafA, Chga, Chgb, Slc2a2). Through ATAC-sequencing, we discovered several differentially accessible genomic regions, including Chd4-bound and Pdx1-controlled MafA Region 3, which had reduced accessibility in Chd4Δβ β-cells. Lastly, we demonstrate that CHD4 impacts human β-cell function and PDX1:CHD4 interactions were reduced in human donor β-cells with type 2 diabetes, demonstrating loss of these interactions is a significant feature of diabetes pathogenesis.

Browsing by Subject "Transcription factor"

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