PO.TB10.05 · 肿瘤生物学
成纤维细胞galectin-3重塑肥胖乳腺肿瘤微环境以促进癌症进展
Fibroblast galectin-3 remodels the obese breast tumor microenvironment to promote cancer progression
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：肥胖影响42.4%的美国成人，与乳腺癌（BC）中更高的肿瘤分级、转移增加和生存降低相关。我们的既往工作揭示了肥胖诱导乳腺中胶原交联酶、基底膜蛋白和基质细胞蛋白galectin-3（LGALS3）的分泌。这些细胞外基质（ECM）改变与肥胖乳腺组织中的成纤维细胞群呈正相关。LGALS3表达升高预示雌激素受体阳性（ER+）BC较差的总生存。我们假设肥胖放大LGALS3成纤维细胞信号传导，破坏ECM组成和组织结构，从而支持BC进展。
方法：Rag1-/-小鼠喂食高脂高糖（HFHS）或低脂低糖（LFLS）饮食16周，以建立肥胖和精瘦表型。将ER+ UCD65 BC细胞单独或与CD146阴性（HS5）成纤维细胞一起双侧植入乳腺脂肪垫，生成四组：LFLS、HFHS、LFLS+CD146阴性、HFHS+CD146阴性。所有小鼠在植入时接受1 mg雌激素，并维持其分配的饮食8周。终点时收集肿瘤、血浆、肺和乳腺脂肪垫用于分析。在CD146阴性成纤维细胞中敲低LGALS3，并在CD146阳性（HS27）成纤维细胞中过表达LGALS3以用于体外研究。在饥饿条件下生成条件培养基并浓缩20倍用于蛋白质印迹分析。
结果：植入CD146阴性成纤维细胞的肥胖小鼠相较于精瘦对照，肿瘤生长增加2.7倍，转移增加8.8倍。CD146阴性成纤维细胞在精瘦和肥胖环境下均显著增强血管生成，但不影响淋巴管生成。肥胖显著破坏了乳腺脂肪垫的胶原组织结构。在植入CD146阴性成纤维细胞的肥胖小鼠中，胶原沉积、巨噬细胞浸润和循环LGALS3水平增加。对LGALS3的基因操作显示，它特异性调节I型胶原分泌而不改变细胞内水平。这种分泌的丧失触发未折叠蛋白反应激活并降低TGF-beta信号传导，进一步支持了以分泌为核心的机制。LGALS3对饮食有反应，限时进食和间歇性禁食分别将循环水平降低2.1倍和2.7倍。
结论：肥胖与CD146阴性成纤维细胞协同，通过LGALS3介导的ECM重塑加速BC侵袭，并得到一种新的胶原分泌转录后调控的支持。LGALS3可作为治疗靶点，并可通过饮食策略加以调节，以减轻肥胖相关的BC风险，可能改善数百万高危患者的结局。
查看英文原文 English abstract
Background: Obesity, affecting 42.4% of U.S. adults, correlates with higher tumor grade, increased metastasis, and reduced survival in breast cancer (BC). Our prior work revealed obesity-induced secretion of collagen-crosslinking enzymes, basement membrane proteins, and the matricellular protein galectin-3 (LGALS3) in the breast. These extracellular matrix (ECM) changes were positively associated with the fibroblast population in obese breast tissue. Elevated LGALS3 expression predicts poorer overall survival in estrogen receptor-positive (ER+) BC. We hypothesize that obesity amplifies LGALS3 fibroblast signaling to disrupt ECM composition and organization, supporting BC progression.
Methods: Rag1-/- mice were fed a high-fat high-sugar (HFHS) or low-fat low-sugar (LFLS) diet for 16 weeks to establish obese and lean phenotypes. ER+ UCD65 BC cells were implanted bilaterally into the mammary fat pad alone or with CD146 neg (HS5) fibroblasts, generating four groups: LFLS, HFHS, LFLS + CD146 neg , and HFHS + CD146 neg . All mice received 1 mg of estrogen at implantation and remained on their assigned diets for eight weeks. Tumors, plasma, lungs, and mammary fat pads were collected at endpoint for analyses. LGALS3 was knocked down in CD146 neg fibroblasts and overexpressed in CD146 pos (HS27) fibroblasts for in vitro studies. Conditioned media was generated under starvation conditions and concentrated 20x for western blotting.
Results: Obese mice implanted with CD146 neg fibroblasts exhibited a 2.7-fold increase in tumor growth and 8.8-fold increase in metastasis compared with lean controls. CD146 neg fibroblasts significantly enhanced angiogenesis in both lean and obese settings but did not affect lymphangiogenesis. Obesity significantly disrupted the collagen organization of the mammary fat pads. In obese mice, with CD146 neg fibroblasts, increased collagen deposition, macrophage infiltration, and circulating levels of LGALS3. Genetic manipulation of LGALS3 showed that it specifically regulates collagen I secretion without altering intracellular levels. This loss of secretion triggered unfolded protein response activation and reduced TGF-beta signaling, further supporting a secretion-focused mechanism. LGALS3 was diet-responsive, with time-restricted feeding and intermittent fasting lowering circulating levels by 2.1 and 2.7-fold, respectively.
Conclusions : Obesity synergizes with CD146 neg fibroblasts to accelerate BC aggression through LGALS3-mediated ECM remodeling, supported by a novel post-transcriptional control of collagen secretion. LGALS3 can serve as a therapeutic target and is modifiable by dietary strategies to mitigate obesity-associated BC risks, potentially improving outcomes for millions of at-risk patients.
利益披露 Disclosure
E. E. Bamberg, None..
K. Vinod-Paul, None..
A. L. Pyo, None..
K. C. Hansen, None..
C. A. Sartorius, None..
P. S. MacLean, None..
P. Kabos, None..
H. Brechbuhl, None.