Brequinar Sodium

Laboratory experiments with cancer cells reveal two ways in which tumors evade drugs designed to starve and kill them, a new study shows. NEW YORK, Nov. 26, 2024 /PRNewswire/ -- While chemotherapies successfully treat cancers and extend patients' lives, they are known not to work for everyone for long, as cancer cells rewire the process by which they convert fuel into energy (metabolism) to outmaneuver the drugs' effects. Many of these drugs are so-called antimetabolics, disrupting cell processes needed for tumor growth and survival. Three such drugs used in the study — raltitrexed, N-(phosphonacetyl)-l-aspartate (PALA), and brequinar — work to prevent cancer cells from making pyrimidines, molecules that are an essential component to genetic letter codes, or nucleotides, that make up RNA and DNA. Cancer cells must have access to pyrimidine supplies to produce more cancer cells and to produce uridine nucleotides, a primary fuel source for cancer cells as they rapidly reproduce, grow, and die. Disrupting the fast-paced but fragile pyrimidine synthesis pathways, as some chemotherapies are designed to do, can rapidly starve cancer cells and spontaneously lead to them dying (apoptosis). Led by researchers at NYU Langone Health and its Perlmutter Cancer Center, the new study shows how cancer cells survive in an environment made hostile by the persistent shortage of the energy from glucose (the chemical term for blood sugar) needed to drive tumor growth. This better understanding of how cancer cells evade the drugs' attempts to kill them in a low-glucose environment, the researchers say, could lead to the design of better or more effective combination therapies. Publishing in the journal Nature Metabolism online Nov. 26, study results showed that the low-glucose environment inhabited by cancer cells, or tumor microenvironment, stalls cancer cell consumption of existing uridine nucleotide stores, making the chemotherapies less effective. Normally, uridine nucleotides would be made and consumed to help make the genetic letter codes and fuel cell metabolism. But when DNA and RNA construction is blocked by these chemotherapies, so too is the consumption of uridine nucleotide pools, the researchers found, as glucose is needed to change one form of uridine, UTP, into another usable form, UDP-glucose. The irony, researchers say, is that a low-glucose tumor microenvironment is in turn slowing down cellular consumption of uridine nucleotides and presumably slowing down rates of cell death. Researchers say cancer cells need to run out of pyrimidine building blocks, including uridine nucleotides, before the cells will self-destruct. In other experiments, low-glucose tumor microenvironments were also unable to activate two proteins, BAX and BAK, sitting on the surface of mitochondria, a cell's fuel generator. Activation of these trigger proteins disintegrates the mitochondria, and instantly sets off a series of caspase enzymes that help initiate apoptosis (cell death). "Our study shows how cancer cells manage to offset the impact of low-glucose tumor microenvironments, and how these changes in cancer cell metabolism minimize chemotherapy's effectiveness," said study lead investigator Minwoo Nam, PhD, a postdoctoral fellow in the Department of Pathology at NYU Grossman School of Medicine and Perlmutter Cancer Center. "Our results explain what has until now been unclear about how the altered metabolism of the tumor microenvironment impacts chemotherapy: low glucose slows down the consumption and exhaustion of uridine nucleotides needed to fuel cancer cell growth and hinders resulting apoptosis, or death, in cancer cells," said senior study investigator Richard Possemato, PhD. Possemato is an associate professor in the Department of Pathology at NYU Grossman School of Medicine and also a member of Perlmutter Cancer Center. Possemato, who is also coleader of the Cancer Cell Biology Program at Perlmutter, says his team's study results could one day be used to develop chemotherapies or combination therapies that would change or trick cancer cells into responding the same way in a low-glucose microenvironment as they would in an otherwise stable glucose microenvironment. He also says that diagnostic tests could be developed to measure how a patient's cancer cells would most likely respond to low-glucose microenvironments and to predict how well a patient might respond to a particular chemotherapy. Possemato says his team has plans to investigate how blocking other cancer cell pathways might trigger apoptosis in response to these chemotherapies. Some experimental drugs, such as Chk-1 and ATR inhibitors, already exist that might accomplish this, he notes, but more need to be investigated because Chk-1 and ATR inhibitors are not well tolerated by patients. For the study, researchers performed a scan of 3,000 cancer cell genes known to be involved in cell metabolism to determine, by deletion, which were necessary for cancer cell survival after chemotherapy. Most of the genes they found that were essential to cell survival in low-glucose tumor environments were also involved in pyrimidine synthesis, a precise biological pathway targeted by many chemotherapies. This focused their experiments on how different lab-grown clones of cancer cells responded to low-glucose after chemotherapy and what other chemical processes were impacted by depressed sugar levels. Funding support for the study was provided by National Institutes of Health grants P30CA016087, R01CA286141, R01CA214948, R01GM132491, and R35GM139610. Additional funding support came from the Pew Charitable Trusts, Alexander and Margaret Stewart Trust, and the American Cancer Society. Besides Nam and Possemato, other NYU Langone researchers involved in this study are co-investigators Wenxin Xia, Abdul Hannan Mir, and Tony Huang. Media Inquiries: David March 212-404-3528 [email protected] STUDY LINK WILL BECOME ACTIVE AFTER EMBARGO LIFTS: STUDY DOI: 10.1038/s42255-024-01166-w SOURCE NYU Langone Health System WANT YOUR COMPANY'S NEWS FEATURED ON PRNEWSWIRE.COM? 440k+ Newsrooms & Influencers 9k+ Digital Media Outlets 270k+ Journalists Opted In GET STARTED

类器官可以定义为具有干细胞潜能的细胞，在3D培养系统下孵育，通过粘附聚集，自组织，分化成具有相应器官组织形态的3D细胞团。类器官与其复制和模拟其独特生物学特性的亲本细胞具有高度的相似性。此外，类器官能够自我更新和自我组织，包含多种细胞类型，执行某些特定功能，并形成与体内器官相似的空间结构。因此，类器官是研究疾病发生、发展和进展的重要模型。肿瘤类器官可通过术前活检或术后肿瘤切除构建，在个体化药物敏感性预测中具有重要作用。因此，类器官模型为药物筛选和个体化药物治疗提供了更好的选择。通过补充现有的模型系统，类器官扩大基础研究的潜力正得到越来越普遍的认识。1、类器官的关键发展历史类器官的研究可以追溯到1907年，当时Wilson等人在体外条件下培养机械分离的海绵细胞形成功能有机体。1975年，一项研究培养了原代人角质形成细胞和3T3成纤维细胞，产生了类似于人表皮的分层鳞状上皮菌落。到20世纪80年代，人类首次从小鼠胚胎中分离并获得了多能干细胞(PSCs)，并相继发现了间充质干细胞(MSCs)、人胚胎干细胞(ESCs)和诱导多能干细胞(iPSCs)。干细胞技术的发展和进步为类器官领域提供了新的视角。2009年，体外培养肠成体干细胞(ASCs)形成具有隐窝绒毛结构的小肠类器官，这是类器官领域具有里程碑意义的事件，证明了干细胞在体内分化成类似器官的空间结构的潜力。从那时起，类器官培养技术蓬勃发展，并建立了来自各种器官的类器官，如脑，视网膜，肺，胃，肝，胆管，胰腺和肾脏。2、类器官的细胞来源类器官是器官或组织的三维(3D)小型化版本，来源于具有干细胞潜能的细胞，可以自组织和分化为三维细胞团，再现其在体内对应的形态和功能。类器官培养是一种新兴的3D培养技术，目前已经产生了来自脑、肺、心、肝、肾等各种器官和组织的类器官。类器官的所有这些特征为药物发现、大规模药物筛选和精准医学开辟了新的机会。干细胞是原始的、未分化的细胞，能够分化成许多不同的特化细胞类型。由于具有自我更新和多向分化的潜力，类器官可以从干细胞中建立，包括ESCs、iPSCs和ASCs(图1)。干细胞发育为类器官的过程类似于器官获得独特组织的方式，主要涉及自组织。图1 体外形成类器官的策略。建立类器官的细胞来源包括胚胎干细胞(ESCs)、成体干细胞(ASCs)、诱导多能干细胞(iPSCs)和肿瘤细胞。来自健康/患者个体的切除和/或活检标本通过与各种信号因子孵育分离成单细胞形成类器官 (Created with BioRender.com).其中ipsc衍生的类器官成熟程度低，与胚胎或早期胎儿组织相似，可用于器官发生研究。esc衍生的类器官比ipsc衍生的类器官具有更高的成熟度，可用于模拟后期器官发生阶段。asc衍生的类器官更接近于成人组织。肿瘤细胞衍生的类器官是一个特殊的例子，因为它们代表了成人肿瘤的特征。图2 不同细胞来源的类器官的成熟程度（Createdwith BioRender.com）3、类器官的培养方法在培养类器官时需要考虑以下因素。首先，由于类器官的三维结构，需要提供三维培养环境，这可以通过将类器官嵌入基质中或应用气液界面(ALI)培养技术来实现。第二，建立适当的区域认同是类器官培养过程中的关键环节，需要正确调控发育和分化相关的信号通路。最后，不同类型的类器官需要不同的营养来发育和分化到终末阶段。因此，需要确保提供足够的营养物质和生长因子。这包括氨基酸、维生素、矿物质、葡萄糖等，以及特定的生长因子和激素。与传统的二维培养相比，类器官培养系统具有保存亲本基因表达和突变特征，以及在体外长期维持亲本细胞功能和生物学特性的独特优势。在三维体系中培养的细胞能够更好地体现细胞的复杂结构和特定细胞功能，与亲本具有高度的契合度，同时保持亲本的遗传稳定性和染色质异质性。这些细胞可在1 ~ 2周内迅速扩增，并可稳定传代和低温保存。4、类器官的生物医学应用类器官可以作为疾病模型来了解人类肝胆疾病的机制和生理病理。类器官是药物筛选和毒性试验的理想模型。患者来源的类器官可用于预测患者对药物和个性化治疗的特异性反应。此外，类器官的低温保存使生物库的建立成为可能。类器官的其他生物医学应用包括生物标志物的发现和再生医学。图3 类器官在生物医学上的应用首先，类器官来源于人类，可以概括人类的生理系统。二是效率高。ASCor psc衍生的类器官快速且相对容易建立。第三，在大规模基因组筛选或药物筛选中，类器官在各方面都表现出稳定性。最后是个性化。类器官可以从单个组织或细胞中生成，有助于实现精确诊断和治疗。这些优点赋予了类肝胆器官广泛的生物医学应用。肝胆类器官技术的快速发展，为在接近自然的生理或病理条件下研究肝胆系统的细胞发育、组织维持和发病机制提供了更好的选择。表1 类器官在疾病建模中的应用4.1应用于癌症方面的PDX模型在癌症方面，目前最常用的模型主要包括人肿瘤细胞系和患者来源的异种移植(PDX)模型。已成功生成肺、结直肠、胰腺、乳腺、前列腺和卵巢肿瘤等多种肿瘤PDX模型。然而，也存在一些限制因素，比如异种移植模型通常是在少量肿瘤组织中建立的，不能完全继承原发肿瘤的基因突变。随着PDXs的生长，人肿瘤的间质逐渐被鼠间质所取代，PDX模型的许多研究结果尚未在人体试验中得到证实。此外，PDX模型的经济成本和时间成本高，成功率低，长期培养后，类肿瘤保留了亲代肿瘤的异质性和组织病理学特征，并保留了其三维结构等。表2 目前癌症研究的临床前模型比较此外，肿瘤样本可通过切除或活检获得，并分离成单细胞形成类肿瘤。从肿瘤细胞中建立类肿瘤，并通过浸没法与自体T细胞共培养，可诱导T细胞的特异性抗肿瘤作用，导致类肿瘤的损伤和死亡。应用ALI方法，将肿瘤组织作为初始细胞材料，生成保存癌相关成纤维细胞和免疫细胞的类瘤细胞，可以在体外重现复杂的肿瘤微环境。图4 肿瘤免疫微环境与类肿瘤的重述(Created With BioRender.com)4.2应用于药物研究的类器官模型此外，类器官在药物相关研究中具有广泛的模型优势。寨卡病毒可以使孕妇感染后导致流产和婴儿出生缺陷。Li等人的一项研究表明，亚甲基蓝通过阻断病毒蛋白酶NS3和NS2B的相互作用，保护脑类器官细胞免受寨卡病毒感染。最近的另一项研究表明hev -宿主在肝类器官中的相互作用，并报道brequinar和homharingtonine是有效的抗hev药物细菌感染的肠道类器官已被用作药物发现的先进平台。4.3精密医学和再生医学类器官在精准医疗领域显示出巨大的潜力，精准医疗的目标是根据患者的特定基因组学和代谢组学为其量身定制医疗方案通过提供一个更具有生理学相关性和个性化的人体器官或组织模型，类器官可用于预测个体患者对药物和其他治疗的反应。再生医学是指修复、再生或替换受损或缺失的细胞、组织或器官以恢复正常结构和功能的生物和工程方法。器官移植对于治疗器官衰竭患者至关重要，但它面临着各种挑战，如严重的移植排斥反应和供体日益短缺。5、局限性和未来展望过去十年，类器官技术确实取得了显著的进步，这主要得益于生物学、工程学以及医学等多学科的交叉融合。类器官的优势在于它们能够模拟人体内的生理环境，从而更真实地反映生物体的生理和病理过程。这使得类器官在疾病建模、药物筛选以及基因治疗等领域具有巨大的应用潜力。类器官技术面临的挑战主要有以下几点：1.技术复杂性：类器官的培养和生成需要高度专业的技术和设备，包括细胞培养、基因编辑、生物材料等方面的技术。这些技术的复杂性和成本限制了类器官的广泛应用。2.伦理和法律问题：类器官技术涉及到人类细胞和组织的操作，因此存在伦理和法律问题。例如，使用人类胚胎干细胞进行类器官培养可能引发关于生命起源和尊严的争议。3.可重复性和标准化：目前，类器官的培养方法和技术尚未实现标准化，不同实验室和研究团队之间的结果可能存在差异。这限制了类器官研究的可重复性和可比性，也阻碍了其在临床应用中的推广。4.功能性验证：尽管类器官可以模拟人体内的生理环境，但它们与真实的人体器官在功能和结构上仍存在一定差异。因此，对于类器官在药物筛选和疾病建模等方面的应用，需要进行充分的功能性验证以确保其准确性和可靠性。确实，类器官培养在技术和可重复性方面仍存在一些挑战。只有少数实验室能够进行类器官培养，不同研究小组之间的实验可重复性较低，这主要是由于技术复杂性和缺乏标准化方法。此外，类器官的细胞发育和成熟度有限，这限制了它们作为优秀组织生物学模型的应用。对于类器官培养用ECM或水凝胶的研究，人工合成的基质材料可以提供更明确的化学定义和成分，从而更好地模拟真实的组织环境。这些材料可以根据不同的要求进行调整，以满足不同类器官培养的需求。尽管面临这些挑战，但随着技术的不断发展和改进，类器官技术有望在生物医药领域发挥更大的作用。未来，通过克服技术障碍、加强国际合作以及建立标准化的研究和应用规范，类器官技术有望为疾病治疗、药物研发和个性化医疗等领域带来更多的突破和创新。参考文献Yang S, Hu H, Kung H, Zou R, Dai Y, Hu Y, Wang T, Lv T, Yu J, Li F. Organoids: The current status and biomedical applications. MedComm (2020). 2023 May 17;4(3):e274. doi: 10.1002/mco2.274.识别微信二维码，添加生物制品圈小编，符合条件者即可加入生物制品微信群！请注明：姓名+研究方向！版权声明本公众号所有转载文章系出于传递更多信息之目的，且明确注明来源和作者，不希望被转载的媒体或个人可与我们联系(cbplib@163.com)，我们将立即进行删除处理。所有文章仅代表作者观点，不代表本站立场。