E2F family transcription factors are directly regulated by TRIM28 to promote castration-resistance in prostate cancer

E2F家族转录因子受TRIM28直接调节促进前列腺癌去势抵抗

• 批准号: 10445046
• 负责人: Ka wing Fong
• 金额: $ 7.65万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-05 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10445046
• 关键词: American; Androgen Antagonists; Androgen Receptor; Androgens; Antibodies; Binding; Biological Assay; CRISPR/Cas technology; Cancer Cell Growth; Cancer Etiology; Cancer Patient; Castration; Cell Cycle; Cell Cycle Progression; Cell Extracts; Cell Line; Cell Proliferation; Cells; Cessation of life; ChIP-seq; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; DNA Binding; DNA biosynthesis; E2F transcription factors; Family; Gene Expression; Generations; Genetic Transcription; Genomic approach; Genomics; Growth; Harvest; Human; Immunohistochemistry; LNCaP; Luciferases; Malignant Neoplasms; Malignant neoplasm of prostate; Mediating; Metastatic Prostate Cancer; Oncogenic; Pathway interactions; Patients; Play; Promoter Regions; Proteins; RNA; Receptor Signaling; Regulation; Reporter; Reporting; Resistance; Role; Running; Signal Transduction; Specimen; Testing; Tissue Microarray; Transactivation; Transcriptional Activation; Ubiquitination; Western Blotting; Xenograft procedure; advanced prostate cancer; androgen deprivation therapy; androgen sensitive; biobank; castration resistant prostate cancer; cell growth; cofactor; cohort; efficacy evaluation; enzalutamide; experimental study; genetic signature; genome-wide; inhibitor; knock-down; men; mutant; prevent; promoter; prostate cancer cell; prostate cancer cell line; prostate cancer progression; small hairpin RNA; small molecule inhibitor; targeted treatment; therapeutic target; transcription factor; transcriptome; tumor growth; tumor xenograft; tumorigenic

Prostate cancer (PCa) is the second-leading cause of cancer-related death in American men. Androgen deprivation therapies that target the androgen receptor (AR) are the mainstay treatment for metastatic PCa. New generation anti-androgen enzalutamide (Enz) significantly increases PCa patient survival. However resistance to Enz develops rapidly. Importantly, castration- resistant prostate cancer (CRPC) is driven primarily by aberrant activation of the AR in the milieu of low androgen. The AR exerts its tumorigenic roles mainly through genomic regulation of target gene expression. This genomic action is tightly regulated by a number of cofactors, and one of which is TRIM24. We recently reported that TRIM28 is an upstream regulator of TRIM24 protein stability in CRPC, where both TRIM24 and TRIM28 expression is highly elevated. Mechanistically, TRIM28 stabilizes TRIM24 by preventing TRIM24 from SPOP-driven ubiquitination and degradation, and thereby TRIM24 is able to reactivate AR signaling in CRPC. To explore the TRIM28-mediated downstream signaling, genome-wide transcriptome analysis revealed that TRIM28 engaged in various oncogenic pathway including cell cycle and DNA replication. By interrogating cell cycle signature genes, we showed that TRIM28 induces E2F1, E2F2 and E2F3 gene expression in PCa. In addition, TRIM28 ChIP-seq revealed that TRIM28 directly binds to promoter region of transcription factor E2F1-E2F3, which play a pivotal role in activating transcription of the genes required for cell cycle progression. Further, deregulated expression or activity of the E2F family has often been detected in many human cancers, which leads to uncontrolled cell proliferation. In this proposal, we hypothesize that E2F transcription factor is a critical downstream target of TRIM28 and clinically-available E2F small molecules inhibitor LY101-4B may suppress CRPC progression. To test this hypothesis, three specific aims are proposed. In Aim1 we will first validate the direct regulation of E2F1-E2F3 gene expression by TRIM28 with the use of genomic approaches. Aim2 will examine clinical expression of E2F and evaluate the efficacy of E2F inhibitor in CRPC cell lines and xenografts.

前列腺癌（PCa）是美国男性癌症相关死亡的第二大原因。