Inhibition of proliferation by Laminin

描述（由申请人提供）：细胞外基质（ECM）大分子是肿瘤微环境的主要组分，并参与癌症进展相关过程，包括整合素介导的容许增殖共信号。出乎意料的是，我们实验室的初步数据表明，基底膜ECM大分子层粘连蛋白-332（Ln-332）对癌细胞具有抗增殖作用。在进一步的检查中，Ln-332的生长抑制似乎是继发于整合素介导的过程，该过程使癌细胞脱离Warburg样代谢，其本身是快速增殖所需的。因此，分泌其自身Ln-332底物的癌细胞系804 G在肾包膜异种移植物中形成小肿瘤。两个Ln-332亚基中的任一个的敲低（804 G-kd）导致Ln-332分泌大大降低。注射到无胸腺小鼠的肾包膜下，804 G-kd细胞形成比804 G亲本大>50倍的肿瘤，其中可检测到增殖增加（Ki-67）和葡萄糖摄取增加（GLUT-1表面表达）的标志物。为了解释这种急剧的增殖性增加，我们比较了代谢参数。在804 G-kd中，我们检测到向有氧糖酵解（瓦尔堡样代谢）的转变，其特征在于GLUT 1表面表达增加，NADPH/NADP比率增加，葡萄糖摄取和乳酸产生增加，所有有氧糖酵解标志。如果将804 G-kd细胞接种在外源性Ln-332底物上，则需氧糖酵解转变逆转。此外，在804 G细胞中，通过基于抗体的<$1抑制而不是通过敲低<$4整联蛋白来表型化该转变，表明在两种Ln-332整联蛋白受体中，<$3 <$1而不是<$6 <$4介导Ln-332代谢效应。总之，这些数据支持Ln-332通过代谢重编程负调节增殖的概念，代谢重编程阻止有氧糖酵解。在这个应用程序中，我们专注于研究连接ECM启动的信号与代谢酶网络的分子机制，希望为癌症研究的新方向开辟新天地。在目标1中，我们将测试这一假设，即整合素1通过抑制Warburg样代谢负调控增殖。在目标2中，我们将确定整合素3 <$1下游信号负调节有氧糖酵解的分子机制。如果成功，该项目将深化微环境对肿瘤生长调节的现有知识，并有可能为目前不可预见的癌症治疗策略创造令人兴奋的机会。

DESCRIPTION (provided by applicant): Extracellular matrix (ECM) macromolecules are major components of the tumor microenvironment and are involved in cancer progression-related processes including integrin mediated permissive proliferative co-signals. Unexpectedly, preliminary data in our laboratory indicate that the basement membrane ECM macromolecule, Laminin-332 (Ln-332), has an anti-proliferative effect on cancer cells. On further examination, growth inhibition by Ln-332 appears to be secondary to an integrin mediated process that shifts cancer cells out of Warburg-like- metabolism, itself required for fast proliferation. Thus, the carcinoma cell line 804G which secretes its own Ln-332 substrate, forms small tumors in kidney capsule xenografts. Knockdown (804G-kd) of either of two Ln-332 subunits leads to greatly decreased Ln-332 secretion. Injected in the subrenal capsule of athymic mice, 804G-kd cells form tumors >50 fold larger than 804G parental, in which markers of both increased proliferation (Ki-67) and glucose uptake (GLUT-1 surface expression) are detectable. To account for this drastic proliferative increase, we compared metabolic parameters. In 804G-kd we detected a shift toward aerobic glycolysis (Warburg---like metabolism) characterized by increased GLUT1 surface expression, increased NADPH/NADP ratio, increased glucose uptake and lactate production, all aerobic glycolysis landmarks. The aerobic glycolysis shift is reversed if 804G-kd cells are plated on exogenous Ln-332 substrates. Moreover, the shift is phenocopied in 804G cells by antibody-based inhibition of ¿1but not by knockdown of ¿4 integrin, suggesting that, of the two Ln-332 integrin receptors, ¿3¿1 but not ¿6¿4mediates Ln-332 metabolic effects. Taken together, these data support the concept that Ln-332 negatively regulates proliferation by metabolic reprogramming that prevents aerobic glycolysis. In this application, we focus on investigating molecular mechanisms that connect ECM-initiated signaling with metabolic enzyme networks, hoping to break new ground for new directions in cancer research. In Aim 1, we will test the hypothesis that ¿1 integrins negatively regulate proliferation by inhibiting Warburg-like metabolism. In Aim 2, we will identify the molecular mechanism by which integrin ¿3¿1 downstream signaling negatively regulates aerobic glycolysis. If successful, this project will deepen existing knowledge of tumor growth regulation by the microenvironment, with the potential to create exciting opportunities for currently unforeseen cancer treatment strategies.