Lu Yuanhua, Li Hui, Zhao Peiyan, Wang Xinyue, Shao Wenjun, Liu Yan, Tian Lin, Zhong Rui, Liu Haifeng, Cheng Ying
Postdoctoral Research Workstation, Jilin Cancer Hospital, Changchun, 130012, China.
Medical Oncology Translational Research Lab, Jilin Cancer Hospital, Changchun, 130012, China.
Mol Med. 2024 Dec 25;30(1):274. doi: 10.1186/s10020-024-01051-y.
Small cell lung cancer (SCLC) is a highly fatal malignancy, the complex tumor microenvironment (TME) is a critical factor affecting SCLC progression. Cancer-associated fibroblasts (CAFs) are crucial components of TME, yet their role in SCLC and the underlying mechanisms during their interaction with SCLC cells remain to be determined.
Microenvironmental cell components were estimated using transcriptome data from SCLC tissue available in public databases, analyzed with bioinformatic algorithms. A co-culture system comprising MRC5 fibroblasts and SCLC cell lines was constructed. RNA sequencing (RNA-seq) was performed on co-cultured and separately cultured MRC5 and H196 cells to identify differentially expressed genes (DEGs) and enriched signaling pathways. Glycolysis and STING signaling in SCLC cells were assessed using glucose uptake assays, qRT-PCR, and Western blot analysis. Immunohistochemical staining of SCLC tissue arrays quantified α-SMA, HLA-DRA and CD8 expression.
Non-neuroendocrine (non-NE) SCLC-derived CAFs exhibited more abundance and DEGs than NE SCLC-derived CAFs did, which interact with non-NE SCLC cells can induce the enrichment of glycolysis-related genes, increasement of glucose uptake, upregulation of glycolytic signaling proteins in non-NE SCLC cells and accumulation of lactate in the extracellular environment, confirming CAF-mediated glycolysis promotion. Additionally, glycolysis-induced ATP production activated STING signaling in non-NE SCLC cells, which upregulated T cell chemo-attractants. However, CAF abundance did not correlate with CD8 + T cell numbers in SCLC tissues. Additionally, non-NE SCLC cell-educated CAFs exhibited features of antigen-presenting CAFs (apCAFs), as indicated by the expression of major histocompatibility complex (MHC) molecules. Co-localization of HLA-DRA and α-SMA signals in SCLC tissues confirmed apCAF presence. The apCAFs and CD8 + T cells were co-located in the SCLC stroma, and there was a positive correlation between CAFs and regulatory T cell (Treg) abundance.
Our findings suggest that crosstalk between CAFs and non-NE SCLC cells promotes glycolysis in non-NE SCLC cells, thereby increase T cell chemo-attractant expression via activating STING signaling. On the other hand, it promotes the presence of apCAFs, which probably contributes to CD8 + T cell trapping and Treg differentiation. This study emphasizes the pro-tumor function of CAFs in SCLC by promoting glycolysis and impairing T cell function, providing direction for the development of novel therapeutic approaches targeting CAF in SCLC.
小细胞肺癌（SCLC）是一种高度致命的恶性肿瘤，复杂的肿瘤微环境（TME）是影响SCLC进展的关键因素。癌症相关成纤维细胞（CAFs）是TME的关键组成部分，但其在SCLC中的作用以及与SCLC细胞相互作用的潜在机制仍有待确定。
利用公共数据库中SCLC组织的转录组数据，通过生物信息学算法估计微环境细胞成分。构建了包含MRC5成纤维细胞和SCLC细胞系的共培养系统。对共培养和单独培养的MRC5和H196细胞进行RNA测序（RNA-seq），以鉴定差异表达基因（DEGs）和富集的信号通路。使用葡萄糖摄取试验、qRT-PCR和蛋白质印迹分析评估SCLC细胞中的糖酵解和STING信号通路。对SCLC组织芯片进行免疫组织化学染色，定量α-SMA、HLA-DRA和CD8的表达。
非神经内分泌（non-NE）SCLC来源的CAFs比NE SCLC来源的CAFs表现出更多的丰度和DEGs，其与non-NE SCLC细胞相互作用可诱导糖酵解相关基因的富集，增加葡萄糖摄取，上调non-NE SCLC细胞中糖酵解信号蛋白的表达，并在细胞外环境中积累乳酸，证实了CAF介导的糖酵解促进作用。此外，糖酵解诱导的ATP产生激活了non-NE SCLC细胞中的STING信号通路，上调了T细胞趋化因子。然而，CAF丰度与SCLC组织中的CD8+T细胞数量无关。此外，non-NE SCLC细胞诱导的CAFs表现出抗原呈递CAFs（apCAFs）的特征，主要组织相容性复合体（MHC）分子的表达表明了这一点。SCLC组织中HLA-DRA和α-SMA信号的共定位证实了apCAF的存在。apCAFs和CD8+T细胞共定位于SCLC基质中，并且CAFs与调节性T细胞（Treg）丰度之间存在正相关。
我们的研究结果表明，CAFs与non-NE SCLC细胞之间的串扰促进了non-NE SCLC细胞中的糖酵解，从而通过激活STING信号通路增加T细胞趋化因子的表达。另一方面，它促进了apCAFs的存在，这可能有助于CD8+T细胞的捕获和Treg分化。本研究强调了CAFs通过促进糖酵解和损害T细胞功能在SCLC中的促肿瘤作用，为开发针对SCLC中CAF的新型治疗方法提供了方向。
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