Transcriptional Control of Cellular Survival and Proliferation in KSHV-transformed B Cells

KSHV 转化的 B 细胞中细胞存活和增殖的转录控制

• 批准号: 10012433
• 负责人: Eva Henriette Gottwein
• 金额: $ 34.49万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-13 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10012433
• 关键词: AIDS related cancer; AIDS/HIV problem; Acquired Immunodeficiency Syndrome; Address; B Cell Proliferation; B-Cell Lymphomas; B-Lymphocytes; BCL2L11 gene; CCND2 gene; Cancer Etiology; Cancerous; Cell Line; Cell Proliferation; Cell Survival; Cellular biology; ChIP-seq; Complex; DNA; Data; Dependence; Distal; Drug Addiction; Drug Targeting; Elements; Enhancers; Environment; Epigenetic Process; Event; Exhibits; Gene Expression; Genes; Genetic Transcription; Genomic approach; Hematopoietic Neoplasms; Homologous Gene; Human; Human Herpesvirus 8; IRF4 gene; Immunomodulators; In Vitro; Individual; Interferons; Lymphoid; Lymphoma cell; MYC gene; Malignant Neoplasms; Mediating; Mediator of activation protein; Molecular; Oncogenic; Outcome; Public Health; Regulatory Element; Repression; Response Elements; Role; Test Result; Testing; Therapeutic; Therapeutic Intervention; Transcriptional Regulation; Transcriptional Silencer Elements; Tumor Suppressor Proteins; Viral; Work; base; cofactor; effusion; experimental study; functional genomics; improved; in vivo; inhibitor/antagonist; innovation; mRNA sequencing; neoplastic cell; novel; novel strategies; novel therapeutics; overexpression; primary effusion lymphoma; programs; promoter; synergism; therapeutic candidate; transcription factor; viral interferon regulatory factor; viral interferon regulatory factor-3

SUMMARY Kaposi’s sarcoma-associated herpesvirus (KSHV) is a major cause of cancer in the context of HIV/AIDS. We recently showed that KSHV-transformed primary effusion lymphoma (PEL) cell lines exhibit a strong requirement for the cellular lymphoid transcription factor IRF4. This finding places PEL into an emerging group of blood cancers where IRF4 is a key oncogenic driver. A detailed understanding of the oncogenic roles of IRF4 has not been achieved in any of these cancers, but evidence suggests that IRF4 functions as a master transcription factor that induces extensive epigenetic and transcriptional reprogramming. In PEL, IRF4 is required for overexpression of the MYC oncogene, but how KSHV controls IRF4, the molecular mechanism by which IRF4 regulates MYC, and whether IRF4 acts solely through MYC or has additional oncogenic roles is unknown. The long-term objective of this proposal is to determine the downstream effects that underlie the oncogenic roles of IRF4 in PEL and to use our results to develop novel therapeutic strategies. The central hypothesis of this proposal is that KSHV-induced, IRF4-dependent oncogenic transcriptional reprogramming is required for tumor cell survival and proliferation in PEL. This hypothesis is premised on our extensive preliminary work, which has identified both KSHV-encoded and cellular transcription factors that control IRF4 expression and function in PEL. Based on ChIP-Seq and mRNA-Seq experiments, we specifically hypothesize that IRF4, together with its viral and cellular co-factors, associates with promoters and distal cis-regulatory elements to drive an IRF4-dependent oncogenic transcription program, which involves both the silencing of “toxic” tumor suppressors and the overexpression of several essential survival genes, including MYC, but also others. To test our hypothesis, we propose two Specific Aims, i.e. we will: (1) determine which toxic genes must be silenced by IRF4 to promote PEL cell viability and proliferation, and (2) determine which IRF4-stimulated genes are essential IRF4 effectors in PEL cells. Several of the already identified candidates for IRF4 effectors are high-confidence drug targets. We will therefore exploit our results in both aims to identify and test novel therapeutic strategies, in vitro and in vivo. This work uses a cutting-edge approach that integrates hypothesis-driven experiments with unbiased functional genomics approaches. The proposed study is innovative, because the oncogenic outcome of transcriptional reprogramming in the context of KSHV-associated malignancies has not been studied. The proposed work is significant, because it will uncover oncogenic roles of IRF4 in KSHV-mediated B cell proliferation and survival. In addition, results will inform our understanding of IRF4 in B cell biology and its oncogenic role in several hematopoietic malignancies. Results will be impactful, because our studies of IRF4 dependency are expected to result in improved strategies for therapeutic intervention in this incurable cancer.

总结 卡波西肉瘤相关疱疹病毒（KSHV）是HIV/AIDS背景下癌症的主要原因。我们 最近表明，KSHV转化的原发性渗出性淋巴瘤（PEL）细胞系表现出强烈的需要 细胞淋巴转录因子IRF 4。这一发现使PEL成为一个新兴的血型群体， IRF 4是关键致癌驱动因子的癌症。对IRF 4致癌作用的详细了解还没有 在这些癌症中的任何一种都没有实现，但有证据表明IRF 4作为主转录因子发挥作用， 诱导广泛的表观遗传和转录重编程的因子。在PEL中，需要IRF 4用于 MYC癌基因的过度表达，但KSHV如何控制IRF 4，IRF 4 IRF 4调节MYC，IRF 4是否仅通过MYC发挥作用或具有额外的致癌作用尚不清楚。的 这项建议的长期目标是确定作为致癌作用基础的下游效应， IRF 4在PEL中的作用，并利用我们的研究结果开发新的治疗策略。这个问题的核心假设是 推测KSHV诱导的、IRF 4依赖性致癌转录重编程是肿瘤所需的 细胞存活和增殖。这一假设是基于我们广泛的初步工作， 鉴定了KSHV编码的和细胞转录因子，其控制IRF 4在PEL中的表达和功能。 基于ChIP-Seq和mRNA-Seq实验，我们特别假设IRF 4及其病毒 和细胞辅因子，与启动子和远端顺式调节元件相关联，以驱动IRF 4依赖性 致癌转录程序，其中涉及沉默的“有毒”肿瘤抑制因子和 几个必需的生存基因的过度表达，包括MYC，但也有其他。为了验证我们的假设，我们 我们提出了两个具体的目标，即我们将：（1）确定哪些毒性基因必须被IRF 4沉默，以促进 PEL细胞活力和增殖，以及（2）确定哪些IRF 4刺激的基因是必需的IRF 4效应子 在PEL细胞中。已经确定的IRF 4效应物的几个候选者是高置信度的药物靶点。我们 因此，将利用我们的结果，在体外和体内鉴定和测试新的治疗策略。 这项工作使用了一种前沿的方法，将假设驱动的实验与无偏的功能性 基因组学方法。这项研究是创新的，因为转录调控的致癌结果 尚未研究KSHV相关恶性肿瘤背景下的重编程。拟议的工作是 重要的，因为它将揭示IRF 4在KSHV介导的B细胞增殖和存活中的致癌作用。 此外，研究结果将为我们了解IRF 4在B细胞生物学中的作用及其在几种肿瘤中的致癌作用提供信息。 造血系统恶性肿瘤结果将是有影响力的，因为我们对IRF 4依赖性的研究是预期的。 以改善这种无法治愈的癌症的治疗干预策略。