Normalizing arginine metabolism with sepiaptein for immunostimulatory-shift ofHER2+ breast cancer

在癌细胞和肿瘤微环境中，精氨酸代谢通常被分流到 产生多胺，细胞生长和免疫抑制所必需的小聚阳离子代谢物。等 机制部分解释了某些类型的癌症，包括乳腺癌， 免疫疗法然而，在开发纠正精氨酸代谢的方法方面存在关键差距， 提高乳腺癌的免疫原性。我们项目的长期目标是开发一种佐剂 治疗，以改善乳腺癌免疫疗法，副作用小。具体而言，这一目标 一项研究旨在测试一氧化氮合酶（NOS）辅因子的天然前体--Sepiapterin是否 BH 4，可以使乳腺中的精氨酸代谢正常化，以防止癌症形成或增强 乳腺癌免疫治疗我们的中心假设是，sepiapterin分流精氨酸代谢进入 乳腺癌细胞和肿瘤相关巨噬细胞（TAM）中NO合成的途径。这种变化 减少多胺产生，抑制肿瘤生长和免疫抑制机制。这提高 肿瘤免疫治疗的疗效，全身毒性小。我们的假设是基于我们的结果， 和其他人之前的研究精氨酸代谢的两个主要途径，NO生成与多胺 合成，互相对抗。因此，我们发现，sepiapterin增加NO的合成， 生长刺激和免疫抑制分子，如多胺，同时从M2转化TAM 肿瘤内的M1（免疫抑制）至M1（免疫刺激）类型。此外，sepiapterin已经安全地 在人类和动物中用于治疗某些代谢紊乱。理由是，这项研究将有助于 开发了一种新的方法来正常化精氨酸代谢，提高乳腺癌的免疫原性。 我们的假设将通过两个具体目标进行测试：1）确定是否sepiapterin正常化 精氨酸在乳腺肿瘤细胞和肿瘤微环境中的代谢 Sepiapterin用于治疗和预防HER 2阳性乳腺肿瘤的安全性。在目标1中，乳房 用培养物中的sepiapterin处理癌细胞、TAM和乳腺肿瘤，并将它们的代谢物和 测量相应的酶。在目标2中，将携带或倾向于HER 2阳性乳腺肿瘤的小鼠 用sepiapterin处理并测试肿瘤生长的抑制或预防。拟定研究 创新，因为它首次测试了天然产生的NOS前体Sepiapterin是否 （二） 辅助因子，可以正常精氨酸代谢，提高乳腺癌的免疫原性，抑制乳腺癌的发生。 生长或防止乳腺癌形成。这项研究是有意义的，因为它将有一个积极的翻译 通过证明使用sepiapterin作为乳腺癌免疫疗法的佐剂或预防剂的合理性， 乳腺癌的治疗方法鉴于目前没有FDA批准的HER 2阳性的免疫疗法， 乳腺癌，这项研究的成功结果将保证未来的临床试验。

In cancer cells and the tumor microenvironment, arginine metabolism is often shunted into the pathways that produce polyamines, small polycationic metabolites essential for cell growth and immuno-suppression. Such mechanisms in part account for the refractoriness of certain types of cancers, including breast cancer, to immunotherapy. However, there is a critical gap in developing a method to correct arginine metabolism to improve the immunogenicity of breast cancer. The long-term goal of our project is to develop an adjuvant treatment to improve breast cancer immunotherapy with little side effects. Specifically, the objective of this study is to test whether sepiapterin, the naturally-occurring precursor of nitric oxide synthase (NOS) cofactor BH4, could normalize arginine metabolism in the breast to prevent cancer formation or enhance the efficacy of breast cancer immunotherapy. Our central hypothesis is that sepiapterin shunts arginine metabolism into the pathways for NO synthesis in breast cancer cells and tumor-associated macrophages (TAMs). Such shifts reduce polyamine production, suppress tumor growth and immuno-suppressive mechanisms. This improves the efficacy of cancer immunotherapy with little systemic toxicity. Our hypothesis is based on the results of our and others’ previous studies. The two major arginine metabolic pathways, NO production vs. polyamine synthesis, antagonize each other. Consistently, we found that sepiapterin elevates NO synthesis and inhibits growth-stimulatory and immune-suppressive molecules, such as polyamines, while converting TAMs from M2 (immuno-suppressive) to M1 (immuno-stimulatory) types within tumors. Besides, sepiapterin has been safely utilized in humans and animals to treat certain metabolic disorders. The rationale is that this study will help develop a novel method to normalize arginine metabolism and improve the immunogenicity of breast cancer. Our hypothesis will be tested through two SPECIFIC AIMS: 1) Determine whether sepiapterin normalizes arginine metabolism in mammary tumor cells and tumor microenvironment Determine the efficacy and safety of sepiapterin for the treatment and prevention of HER2-positive mammary tumor. In Aim 1, breast cancer cells, TAMs and mammary tumors are treated with sepiapterin in culture, and their metabolites and the respective enzymes are measured. In Aim 2, mice bearing or prone to HER2-positive mammary tumors are treated with sepiapterin and tested for the inhibition or prevention of tumor growth. The proposed study is innovative because it tests for the first time whether sepiapterin, the naturally produced precursor of the NOS ; and 2) cofactor, could normalize arginine metabolism, improve the immunogenicity of breast cancer to inhibit the growth or prevent breast cancer formation. The study is significant because it will have a positive translational impact by justifying the use of sepiapterin as an adjuvant to breast cancer immunotherapy or a preventative agent for breast cancer. Given that there is currently no FDA-approved immunotherapy for HER2-positive breast cancer, successful results of this study will warrant future clinical trials.