The Role and Regulation of Monocarboxylate Transporters 1 and 4 in Epstein-Barr Virus-mediated B Lymphocyte Tumorigenesis

爱泼斯坦-巴尔病毒(EBV)是一种普遍存在的病毒，它在初次感染时建立潜伏期，但可以劫持主机 促进免疫受损宿主肿瘤发生的代谢途径。这项提议的目标是 确定EBV如何通过MCT1和MCT4调节乳酸输出，促进B细胞永生化， 并被利用以获得治疗益处。我的中心假设是EBV在时间上上调MCT1/4到 通过减轻在永生化过程中增加的细胞内乳酸负担来促进B细胞的生长。 这一假说基于乳酸输出对于防止细胞内酸化至关重要的理论基础， 这可能不利于细胞生长。我们实验室发表了在EB病毒使B细胞永生化的过程中 在体外，糖酵解显著上调。我们还观察到细胞外酸化率增加。 (ECar)，这在很大程度上反映了糖酵解过程中乳酸的排泄。然而，乳酸盐出口在 EB病毒介导的B细胞永生化从未被探索过。乳酸出口受血浆调节 膜驻留蛋白单羧酸转运蛋白1和4(MCT1/4)，它们与 肿瘤在各种癌症中的发生和发展。我们观察到细胞外的显著增加 EB病毒B细胞永生化过程中的细胞内乳酸水平。在体外，B细胞的EBV永生化 进入无限增殖的淋巴母细胞样细胞系(LCLS)的细胞诱导两种不同的潜伏期程序，潜伏期 IIB和Latency III.LCLS表达Latency III生长计划，其中所有六个EBV核抗原(EBNA- Lp、1、2、3A、3B和3C)和两个潜伏膜蛋白(LMP1和LMP2)。这个基因 表达程序模仿了许多EBV相关的B淋巴细胞癌，使LCLS成为一个合适的模型 用于研究肿瘤发生的机制。感染后不久，潜伏期III建立之前 在LCLS中，早期EBV感染的B细胞表达潜伏期IIb生长程序，其中只有病毒EBNAs 表达。我们观察到MCT1在等待时间IIb期间上调，而MCT4在等待时间III期间上调， 提示MCT1/4介导的乳酸输出可能在EB病毒驱动的B细胞永生化中起重要作用。我计划 通过追求以下具体目标来检验这一假设： 1)MCT4上调的病毒机制及其在MCT1抑制剂耐药中的作用 2.)在双重MCT1/4抑制中揭示促进生长停滞的潜在变化 3.)探索双重MCT1/4抑制作为病毒相关淋巴瘤的治疗策略。

Epstein-Barr Virus (EBV) is a ubiquitous virus that establishes latency upon primary infection, but can hijack host metabolic pathways to promote tumorigenesis in immune-compromised hosts. The goal of this proposal is to determine how EBV regulation of lactate export through MCT1 and MCT4, can promote B cell immortalization, and be exploited for therapeutic benefit. My central hypothesis is that EBV temporally upregulates MCT1/4 to promote B cell growth by mitigating the increased intracellular lactate burden accrued during immortalization. This hypothesis is based on the rationale that lactate export is crucial for preventing intracellular acidification, which can be detrimental to cell growth. Our laboratory has published that during EBV immortalization of B cells in vitro, glycolysis is significantly upregulated. We also observed increased extracellular acidification rates (ECAR), which is largely a reflection of lactate excreted during glycolysis. However, the role of lactate export in EBV-mediated B cell immortalization has never been explored. Lactate export is regulated by the plasma membrane-resident proteins monocarboxylate transporters 1 and 4 (MCT1/4), which have been associated with tumor development and progression in various cancers. We have observed a significant increase in extracellular and intracellular lactate levels during the course of EBV B cell immortalization. In vitro, EBV immortalization of B cells into indefinitely proliferating lymphoblastoid cell lines(LCLs) induces two distinct latency programs, Latency IIb and Latency III. LCLs express the Latency III growth program, where all six EBV Nuclear Antigens (EBNA- LP, 1, 2, 3A, 3B, and 3C) and two Latent Membrane Proteins (LMP1 and LMP2) are present. This gene expression program mimics that of many EBV-associated B-lymphoid cancers, making LCLs a suitable model for studying mechanisms underlying tumorigenesis. Shortly after infection and prior to Latency III establishment in LCLs, early EBV-infected B cells express the Latency IIb growth program, where only the viral EBNAs are expressed. We have observed that MCT1 is upregulated during Latency IIb, and MCT4 during Latency III, suggesting that MCT1/4-mediated lactate export might be important for EBV-driven B cell immortalization. I plan to test this hypothesis by pursuing the following specific aims: 1.) Determining the viral mechanism for MCT4 upregulation and role in MCT1 inhibitor resistance 2.) Uncovering underlying changes that promote growth arrest in dual MCT1/4 inhibition 3.) Exploring dual MCT1/4 inhibition as a therapeutic strategy in virus-associated lymphomas.