Phosphorylation of BCKDK of BCAA catabolism at Y246 by Src promotes metastasis of colorectal cancer.
Src 对 BCAA Y246 分解代谢 BCKDK 的磷酸化促进结直肠癌的转移。
- 作者列表："Tian Q","Yuan P","Quan C","Li M","Xiao J","Zhang L","Lu H","Ma T","Zou L","Wang F","Xue P","Ni X","Wang W","Liu L","Wang Z","Zhu F","Duan Q
:Branched-chain α-keto acid dehydrogenase kinase (BCKDK), the key enzyme of branched-chain amino acids (BCAAs) metabolism, has been reported to promote colorectal cancer (CRC) tumorigenesis by upregulating the MEK-ERK signaling pathway. However, the profile of BCKDK in metastatic colorectal cancer (mCRC) remains unknown. Here, we report a novel role of BCKDK in mCRC. BCKDK is upregulated in CRC tissues. Increased BCKDK expression was associated with metastasis and poor clinical prognosis in CRC patients. Knockdown of BCKDK decreased CRC cell migration and invasion ex vivo, and lung metastasis in vivo. BCKDK promoted the epithelial mesenchymal transition (EMT) program, by decreasing the expression of E-cadherin, epithelial marker, and increasing the expression of N-cadherin and Vimentin, which are mesenchymal markers. Moreover, BCKDK-knockdown experiments in combination with phosphoproteomics analysis revealed the potent role of BCKDK in modulating multiple signal transduction pathways, including EMT and metastasis. Src phosphorylated BCKDK at the tyrosine 246 (Y246) site in vitro and ex vivo. Knockdown and knockout of Src downregulated the phosphorylation of BCKDK. Importantly, phosphorylation of BCKDK by Src enhanced the activity and stability of BCKDK, thereby promoting the migration, invasion, and EMT of CRC cells. In summary, the identification of BCKDK as a novel prometastatic factor in human CRC will be beneficial for further diagnostic biomarker studies and suggests novel targeting opportunities.
: 支链 α-酮酸脱氢酶激酶 (BCKDK)，支链氨基酸 (BCAAs) 代谢的关键酶，有报道可促进结直肠癌 (CRC) 通过上调 MEK-ERK 信号通路发生肿瘤。然而，转移性结直肠癌 (mCRC) 中 BCKDK 的概况仍然未知。在此，我们报道了 BCKDK 在 mCRC 中的新作用。BCKDK 在 CRC 组织中上调。BCKDK 表达增加与 CRC 患者的转移和不良临床预后相关。敲除 BCKDK 可减少 CRC 细胞体外迁移和侵袭，以及体内肺转移。BCKDK 通过降低上皮标志物 E-cadherin 的表达，增加间质标志物 N-cadherin 和 Vimentin 的表达，促进上皮间质转化 (EMT) 程序。此外，BCKDK-敲除实验结合磷酸蛋白质组学分析揭示了 BCKDK 在调节多个信号转导通路，包括 EMT 和转移中的强大作用。体外和体外酪氨酸 246 (Y246) 位点的 Src 磷酸化 BCKDK。敲除和敲除 Src 下调 BCKDK 的磷酸化。重要的是，Src 对 BCKDK 的磷酸化增强了 BCKDK 的活性和稳定性，从而促进了 CRC 细胞的迁移、侵袭和 EMT。总之，BCKDK 作为人类 CRC 中一种新的前转移因子的鉴定将有利于进一步的诊断生物标志物研究，并提示新的靶向机会。
METHODS::Chronic diseases, including inflammatory bowel disease (IBD) urgently need new biomarkers as a significant proportion of patients, do not respond to current medications. Inflammation is a common factor in these diseases and microbial sensing in the intestinal tract is critical to initiate the inflammation. We have identified ELMO1 (Engulfment and Cell Motility Protein-1) as a microbial sensor in epithelial and phagocytic cells that turns on inflammatory signals. Using a stem-cell-based "gut-in-a-dish" coculture model, we studied the interactions between microbes, epithelium and monocytes in the context of IBD. To mimic the in-vivo cell physiology, enteroid-derived monolayers (EDMs) were generated from the organoids isolated from WT and ELMO1-/- mice and colonic biopsies of IBD patients. The EDMs were infected with the IBD-associated microbes to monitor the inflammatory responses. ELMO1-depleted EDMs displayed a significant reduction in bacterial internalization, a decrease in pro-inflammatory cytokine productions and monocyte recruitment. The expression of ELMO1 is elevated in the colonic epithelium and in the inflammatory infiltrates within the lamina propria of IBD patients where the higher expression is positively correlated with the elevated expression of pro-inflammatory cytokines, MCP-1 and TNF-α. MCP-1 is released from the epithelium and recruits monocytes to the site of inflammation. Once recruited, monocytes require ELMO1 to engulf the bacteria and propagate a robust TNF-α storm. These findings highlight that the dysregulated epithelial ELMO1→MCP-1 axis can serve as an early biomarker in the diagnostics of IBD and other inflammatory disorders.
METHODS:BACKGROUND:Peripheral blood eosinophilia (PBE) is a biomarker of an aggressive multiyear natural history in adults with inflammatory bowel diseases (IBDs). Additionally, PBE at diagnosis is associated with higher disease activity in pediatric-onset IBD. We sought to determine if PBE can function as a biomarker of long-term disease severity in pediatric-onset IBD patients who are followed into adulthood. METHODS:We analyzed a consented, prospective, natural history IBD registry at an adult tertiary center from 2009 to 2018. Prevalence of PBE was evaluated in both pediatric- and adult-onset IBD patients. Demographics, clinical characteristics, and health care utilization data were compared in patients with and without PBE. RESULTS:Among 2800 adult IBD patients, 23.4% had pediatric-onset disease. PBE was found in 34% of the pediatric-onset patients compared with 26.8% of the adult-onset IBD patients (P < 0.001). In the pediatric-onset IBD cohort, PBE was associated with higher rates of allergies (P < 0.0001), but not of asthma, allergic rhinitis, or primary sclerosing cholangitis. In the adult IBD patients with pediatric-onset disease, PBE was associated with higher rates of C-reactive protein elevation (P < 0.0001), erythrocyte sedimentation rate elevation (P < 0.0001), higher health care utilization, and higher average health care charges per year (P < 0.00001). CONCLUSIONS:Peripheral blood eosinophilia was more prevalent in adult IBD patients with pediatric-onset compared with adult-onset disease. Among all IBD patients with long-term follow-up, PBE defined a subgroup with more severe illness. These data suggest that PBE may be a biomarker for a high-risk subgroup with high cost trajectory and long-term severity in pediatric-onset IBD that persists into adulthood.
METHODS::Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with a complex pathogenesis, affecting people of all ages. They are characterized by alternating phases of clinical relapse and remission, depending on the fine balance between immune cells and the gut microbiota. The cross talk between cells of the immune system and the gut microbiota can result in either tolerance or inflammation, according to multifactorial triggers, ranging from environmental factors to genetic susceptibility. Glucocorticoid (GC) administration remains the first-line treatment for IBDs, although long-term use is limited by development of serious adverse effects. Recently, new alternative pharmacological therapies have been developed, although these are not always effective in IBD patients. There is a constant demand for effective new drug targets to guarantee total remission and improve the quality of life for IBD patients. The glucocorticoid-induced leucine zipper (GILZ) has been implicated as a promising candidate for this purpose, in view of its powerful anti-inflammatory effects that mimic those of GCs while avoiding their unwanted adverse reactions. Here we present and discuss the latest findings about the involvement of GILZ in IBDs.