Modulation of the S100A9/CD33 Pathway by the Flavonoids ICA and ICT on the Tumor

背景：髓系抑制细胞是肿瘤微环境中的一种新近衍生的成分，已被确定在肿瘤的维持和发展中起关键作用。这些细胞有助于上调与肿瘤进展相关的炎症，如MRP8/9。黄酮类化合物是一组多酚化合物，通常在植物中发现，具有许多生物学功能，可被证明在抗炎、抗氧化以及最近的抗肿瘤特性等疾病的斗争中有用。从淫羊藿中得到的化合物，特别是其活性化合物淫羊藿苷(ICA)和名为3，5，7-三羟基-4‘-甲氧基-8-(3-羟基-3-甲基丁基)-黄酮衍生物(ICT)，已被证明具有很强的免疫调节和抗肿瘤作用。假设与目的：我们最近发现这两个化合物都具有强大的调节作用，包括下调肿瘤微环境中MDSC和MRP8/14的表达，以及使STAT3、NF-kB和MAPK途径成分失活，在体外对肿瘤细胞的细胞毒作用，以及在小鼠肿瘤模型中减轻肿瘤负担。虽然在认识到这些化合物对其抗癌治疗潜力的作用方面已经取得了很大进展，但对它们的作用机制还知之甚少。特别是，我们假设对MDSC的影响与PDE5的抑制有关，就像伟哥这样的合成药物一样。我们还假设，这些化合物对炎症途径的影响是通过激活和上调磷酸酶来实现的，特别是PP2A，正如之前所说的那样。这种特殊的作用可能与这些化合物对癌细胞的直接细胞毒性作用有关。在体内，这些药物也可能对肿瘤微环境的结构产生直接影响，从而导致其不稳定和抑制肿瘤生长。因此，对ICA和ICT调控MDSC和与癌症相关的炎症标志物的机制的研究将为这些化合物在未来的治疗应用中更接近临床提供洞察力。具体目的：目的1：了解PDE5抑制对ICA/ICT活动的影响。目的：探讨磷酸酶在ICA和ICT失活促炎介质中的作用。目的：研究ICA/ICT对体内肿瘤微环境的调节机制。研究设计：对于目标1，我们将首先继续进行电子建模，以演示ICT与PDE5结合的特殊性。我们将继续通过体外机制研究来评估这种结合，并确定其机制是否类似于 其他PDE5抑制剂，如西地那非，我们的对照组。我们还将确定PDE5抑制的一些效果是否也会影响肿瘤细胞。对于目标2，我们将确定磷酸酶在关键的促炎通路NF-kB、Akt、ERK、p38和STAT3失活中的作用。PP2A和SHP1是唯一的磷酸酶吗？有没有一种特定类型的磷酸酶被ICA和ICT激活。对于目标3，我们将进行体内研究，以了解这些通路的作用以及每一条通路在ICA和ICT的调节作用中所起的重要作用。

DESCRIPTION (provided by applicant): Modulation of the S100A9/CD33 pathway by the flavonoids ICA and ICT on the tumor microenvironment Background: Myeloid-derived suppressive cells are a recently derived component of the tumor microenvironment that has been determined to have a pivotal role in the maintenance and progression of cancer. These cells contribute to the upregulation of inflammatory correlated with tumor progression such as MRP8/9. Flavonoids are a group of polyphenolic compounds, commonly found on plants with many biological abilities that could prove useful in the battle against disease including anti-inflammatory, antioxidant and, more recently, anti-tumorigenic properties. Those obtained from Herba Epimedii, specifically its active compound icariin (ICA) and a derivative named 3, 5, 7-Trihydroxy-4'-methoxy-8-(3-hydroxy-3- methylbutyl)-flavone (ICT), have been shown to have strong immunomodulatory as well as anti-tumorigenic effects. Hypothesis and objective: We have recently shown that both of these compounds have potent modulatory effects that involve the downregulation of MDSC and MRP8/14 from the tumor microenvironment as well as the deactivation of STAT3, NF-kB and MAPK pathway components, cytotoxicity of tumor cells in vitro and the reduction of tumor burden in a mice model of cancer. While strides have been made in recognizing the role of these compounds on their therapeutic potential against cancer, their mechanisms of action is poorly understood. In particular we hypothesize that the effect on MDSC is linked to the inhibition of PDE5 just as seen with synthetic drugs like Viagra. We also hypothesize that the effect of these compounds on inflammatory pathways is mediated by the activation and perhaps upregulation of phosphatases, in particular PP2A as has been suggested previously. This particular effect might be linked to the direct cytotoxic effect of thes compounds on cancer cells. It is also possible that in vivo these drugs could have a direct impact on the architecture of the tumor microenvironment that lead to its destabilization and the inhibition of tumor growth. Therefore the study of the mechanisms involved in the modulation of MDSC and inflammatory markers linked to cancer by ICA and ICT would provide the insight to bring these compounds one step closer to the clinic for future therapeutical applications. Specific aims: Aim1: To understand the role of PDE5 inhibition on ICA/ICT action. Aim 2: To investigate the role of phosphatases on the deactivation of pro-inflammatory mediators by ICA and ICT. Aim 3: To study the regulatory mechanisms of ICA/ICT on the in vivo tumor microenvironment. Study design: For aim 1, we will first continue in silico modeling that demonstrates the specificities of the binding of ICT with PDE5. We will continue our assessment of this binding with mechanistic in vitro studies and determine if the mechanism is similar to that of other PDE5 inhibitors like sildenafil, our control. We will also determine if some of the effect of PDE5 inhibition affect tumor cells as well. For aim 2, we will determine the role of phosphatases on the deactivation of key pro-inflammatory pathways NF-kB, Akt, ERK, p38, and Stat3. Are PP2A and SHP1 the only phosphatases? Is there a specific type of phosphatases that gets activated by ICA and ICT. For aim 3, we will do in vivo studies to understand the role of these pathways and the importance each one of them plays in the modulatory role of ICA and ICT.