? 腫瘤細胞源性乳酸誘導的腫瘤相關巨噬細胞中HMGB1的上調進一步促進結直腸癌的進展

2023年1月，中國科學院大學腫瘤醫院(浙江省腫瘤醫院)放射科;中國科學院基礎醫學與腫瘤研究所，中國科學院大學腫瘤醫院(浙江省腫瘤醫院)結直腸外科;浙江省上消化道腫瘤防治重點實驗室 (Department of Radiology, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), 1 Banshan East Road, Hangzhou 310022, Zhejiang,People’s Republic of China；Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, 1 Banshan East Road, Hangzhou 310022, Zhejiang, People’sRepublic of China；Department of Colorectal Surgery, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), 1 Banshan East Road, Hangzhou 310022, Zhejiang, People’s Republic of China；Key Laboratory of Prevention, Diagnosis and Therapy of Upper Gastrointestinal Cancer of Zhejiang Province, Hangzhou 310022, China) Xinyi Gao老師研究團隊在《Journal of Translational Medicine》上發表論文：

“Upregulation of HMGB1 in tumor-associated macrophages induced by tumor cell-derived lactate further promotes colorectal cancer progression”

“腫瘤細胞源性乳酸誘導的腫瘤相關巨噬細胞中HMGB1的上調進一步促進結直腸癌的進展”

Abstract：

Background: Lactate accumulation leads to an acidic tumor microenvironment (TME), in turn promoting colorectal cancer (CRC) progression. Tumor-associated macrophages (TAMs) are the predominant cells in TME. This study aimed to reveal the regulation mechanism of CRC cell-derived lactate on TAMs and explore the mechanism underlying lactate accumulation-induced aggravation in CRC.

Methods: Cell growth and metastasis were evaluated by colony formation, Transwell, and wound healing assays. Western blot and RT-qPCR were applied to determine the protein and mRNA expression. Flow cytometry was used to analyze the polarization state and apoptotic rate of macrophages induced in THP-1 cells. The lactate in the cell supernatant was quantified using an ELISA kit. Immunofluorescence was performed to visualize the location of High Mobility Group Box 1 (HMGB1). H&E and Ki67 staining assays were used to assess tumorigenesis in nude mice bearing ectopic tumors.

Results: Cell growth and metastasis were promoted in the hypoxic CRC cells. The hypoxic cell supernatant stimulated the M2-type polarization of macrophages. The lactate level increased in hypoxic cancer cells. However, the inhibition of lactate using 3-hydroxy-butyrate (3-OBA) reversed the effects of hypoxia. Also, macrophages showed no promoting effect on cancer cell growth and migration in the presence of 3-OBA. HMGB1 was secreted into the extracellular space of lactate-induced macrophages, further enhancing the malignant behaviors of cancer cells. ERK, EMT, and Wnt signaling pathways were activated in cancer cells due to HMGB1 upregulation.

Conclusions: The lactate metabolized by cancer cells stimulated M2 polarization and HMGB1 secretion by macrophages, aggravating the carcinogenic behaviors of cancer cells.

摘要：

背景

乳酸積累導致酸性腫瘤微環境(TME)，進而促進結直腸癌(CRC)的進展。腫瘤相關巨噬細胞(TAMs)是TME的主要細胞。本研究旨在揭示CRC細胞源性乳酸對TAMs的調控機制，探討乳酸積累誘導CRC加重的機制。

方法

通過菌落形成、Transwell和傷口愈合試驗來評估細胞生長和轉移。Western blot和RT-qPCR檢測蛋白和mRNA的表達。采用流式細胞術分析THP-1細胞誘導巨噬細胞極化狀態及凋亡率。用ELISA試劑盒定量細胞上清液中的乳酸。采用免疫熒光法觀察高遷移率組盒1 (HMGB1)的位置。采用H&E和Ki67染色法評價異位瘤裸鼠的腫瘤發生情況。

結果

低氧CRC細胞促進細胞生長和轉移。低氧細胞上清刺激巨噬細胞的m2型極化。缺氧癌細胞中乳酸水平升高。然而，使用3-羥基丁酸(3-OBA)抑制乳酸逆轉了缺氧的影響。此外，巨噬細胞在3-OBA存在下對癌細胞的生長和遷移沒有促進作用。HMGB1分泌到乳酸誘導的巨噬細胞胞外間隙，進一步增強了癌細胞的惡性行為。由于HMGB1的上調，癌細胞中的ERK、EMT和Wnt信號通路被激活。

結論

癌細胞代謝的乳酸刺激巨噬細胞M2極化和HMGB1分泌，加重了癌細胞的致癌行為。

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