Project description:Substantial data indicate that microRNA-21 (miR-21) is significantly elevated in glioblastoma (GBM) and in many other tumors of various origins. This miRNA has been implicated in various aspects of carcinogenesis, including cellular proliferation, apoptosis and migration. We demonstrate that miR-21 regulates multiple genes associated with glioma cell apoptosis, migration, and invasiveness, including RECK and TIMP3, suppressors of malignancy and inhibitors of matrix metalloproteinases (MMPs). Specific inhibition of miR-21 with antisense olgonucleotides leads to elevated levels of RECK and TIMP3 and therefore reduces MMP activities in vitro and in a human model of glioma in nude mice. Moreover, down-regulation of miR-21 in glioma cells leads to decrease of their migratory and invasion abilities. Our data suggest that miR-21 contributes to the glioma malignancy by down-regulation of MMP inhibitors that leads to activation of MMPs thus promoting invasiveness of cancer cells. Our results also indicate that inhibition of a single oncomir like miR-21 with specific antisense molecules can provide a novel therapeutic approach for “physiological” modulation of multiple proteins whose expression is de-regulated in cancer.
Project description:Glioblastoma (GB), the most aggressive tumor of the central nervous system (CNS), has poor patient outcomes with limited effective treatments available. MicroRNA-21 (miR-21) is a known oncogene, abundantly expressed in many cancer types. MiR-21 promotes glioblastoma progression, and lack of miR-21 reduces tumorigenic potential of tumor. Here, we propose a single adeno-associated virus (AAV) vector strategy targeting miR-21 using the Staphylococcus aureus Cas9 ortholog (SaCas9) guided by a single-guide RNA (sgRNA). Our results demonstrate that AAV8 is a well-suited AAV serotype to express SaCas9-KKH/sgRNA at the tumor site in an orthotopic glioblastoma model. The SaCas9-KKH induced a genomic deletion, resulting in lowered miR-21 levels in the brain, leading to reduced tumor growth and improved overall survival. In this study we demonstrated that a single AAV-mediated mir-21 disruption influences glioma development resulting in beneficial anti-tumor outcomes in GB-bearing mice.
Project description:<p>BRCA1 mutations are a hallmark of hereditary ovarian cancer, strongly linked to deficiencies in homologous recombination (HR) DNA repair and impaired DNA replication fork protection. However, its roles in cancer progression beyond maintaining genomic integrity remain poorly understood. Through metabolomics approaches, we found BRCA1-deficiency strikingly increased choline metabolism. Loss of BRCA1 promotes choline uptake through upregulating choline transporter-like protein 4 (CTL4). BRCA1 directly binds and recruits EZH2-mediated H3K27Me3 deposition to CTL4 promoter. CTL4 was therefore overexpressed in ovarian cancer tissues with BRCA1 mutations. Furthermore, BRCA1-deficiency significantly promotes ovarian cancer invasion, while inhibition of CTL4 reverses the high metastatic potential of BRCA1-deficient ovarian cancer cells, suggesting the functionality and specificity of CTL4 as a therapeutic target. Additionally, we discovered that phosphocholine, the choline metabolite increased by CTL4 overexpression, interacted with and stabilized the epithelial-to-mesenchymal transition inducer FAM3C in BRCA1-deficient ovarian cancer cells. Importantly, we identified a potent CTL4 inhibitor, DT-13, which significantly reduces choline metabolism and effectively suppresses metastasis in BRCA1-deficient ovarian cancers. Therefore, our study uncovers a mechanism underlying metastasis in BRCA1-deficient cancers and identifies CTL4 as a therapeutic target for metastatic ovarian cancer patients with BRCA1 mutations.</p>
Project description:Method: Analysis of the transcriptomal changes of EV-GFP uptake by microglia after implantation of glioma cells into miR-21 null mouse brain. Result: miR-21 is transferred from glioma to microglia through EV, resulting in downregulation of miR-21 target mRNAs
Project description:Method: Analysis of the transcriptomal changes in wildtype mouse glioma tumor cells compared to miR-21 knockout glioma tumor cells (GL261) Result: transcriptional changes are driven through miR-21
Project description:SERPINE1 is involved in various biological processes, but its roles in promoting or suppressing tumorigenesis remain controversial. To understand the underlying mechanisms, we focused on the effects of SERPINE1 downregulation on cell phenotypes, particularly proliferation and invasion, across three types of tumors. High SERPINE1 levels in breast cancer (BRCA) and low-grade glioma (LGG) were associated with poor prognosis. In contrast, elevated SERPINE1 levels in skin cutaneous melanoma (SKCM) correlated with better outcomes. SERPINE1 knockdown resulted in increased xenograft growth in the melanoma cell line C918. This was characterized by the promotion of the cell cycle through the modulation of minichromosome maintenance protein expression and the activity of p53 and SMAD3. In breast cancer cells (MDA-MB-231) with SERPINE1 knockdown, there was decreased xenograft growth and cell proliferation, attributed to a reduction in the uPAR-mediated ERK/p38 activity ratio. With SERPINE1 knockdown, both C918 and MDA-MB-231 cells demonstrated reduced invasion capabilities, decreased matrix metalloproteinase (MMP) activity, and reduced lung metastasis. In low-grade glioma cells (H4), SERPINE1 knockdown led to decreased cell proliferation due to a reduction in the HSP90-mediated ERK/p38 activity ratio. However, it increased invasion and MMP activity, particularly of MMP-1, regulated by the HSP90-p38 axis. Collectively, our findings reveal that SERPINE1 exerts diverse effects on cell proliferation and invasion through context-dependent mechanisms. These results suggest that targeting SERPINE1 may offer personalized therapeutic strategies to enhance treatment precision and reduce adverse effects.