KIT Signaling Promotes Growth of Colon Xenograft Tumors in Mice and Is Up-Regulated in a Subset of Human Colon Cancers.
KIT Signaling Promotes Growth of Colon Xenograft Tumors in Mice and Is Up-Regulated in a Subset of Human Colon Cancers.
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DOI：
10.1053/j.gastro.2015.05.042
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发表时间：
2015-09
期刊：
影响因子：
29.4
通讯作者：
Rothenberg ME
中科院分区：
文献类型：
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作者：
Chen EC;Karl TA;Kalisky T;Gupta SK;O'Brien CA;Longacre TA;van de Rijn M;Quake SR;Clarke MF;Rothenberg ME
受体酪氨酸激酶（RTK）抑制剂具有先进的结肠癌治疗。我们研究了RTK KIT在人类结肠癌发展中的作用。通过免疫组织化学分析了137例患者来源的结肠肿瘤及其相关异种移植物的阵列，以测量KIT及其配体KITLG的水平。在DLD 1、HT 29、LS 174 T和COLO 320结肠癌细胞系中以及在UM-COLON#8和POP 77异种移植物中，通过来自慢病毒载体的小发夹RNA的表达稳定敲低KIT和/或KITLG;仅用载体转导的细胞用作对照。通过实时定量逆转录PCR、单细胞基因表达分析、流式细胞术以及免疫组织化学、免疫印迹和功能测定来分析细胞。异种移植肿瘤在免疫受损小鼠中从对照和KIT敲低的DLD 1和UM-COLON#8细胞生长并进行比较。一些小鼠在注射癌细胞后给予RTK抑制剂伊马替尼;肿瘤生长基于生物发光测量。我们使用有限稀释分析评估致瘤性。KIT和KITLG在人结肠肿瘤的亚群中不均匀表达。与对照细胞相比，KIT的敲低降低了结肠癌细胞系的增殖和小鼠异种移植肿瘤的生长。KIT敲除细胞的肠上皮细胞标志物的表达增加，循环基因的表达减少，并且出乎意料地，LGR 5相关基因的表达增加。在DLD 1、POP 77或UM-COLON#8细胞系中未检测到KIT激活突变。然而，KITLG敲低的DLD 1细胞形成的异种移植肿瘤比对照细胞小。单个CD 44+细胞的基因表达分析表明，KIT可能通过KITLG自分泌和/或旁分泌信号传导促进生长。伊马替尼抑制培养物中KIT+结肠癌类器官的生长和小鼠中异种移植肿瘤的生长。具有内源性KIT表达的癌细胞在小鼠中更具致瘤性。KIT和KITLG由人结肠肿瘤的子集表达。KIT信号传导通过其配体KITLG以自分泌或旁分泌方式促进培养物中的结肠癌细胞和类器官以及小鼠中的异种移植肿瘤的生长。表达KIT的结肠肿瘤患者可能受益于KIT RTK抑制剂。
Receptor tyrosine kinase (RTK) inhibitors have advanced colon cancer treatment. We investigated the role of the RTK KIT in development of human colon cancer. An array of 137 patient-derived colon tumors and their associated xenografts were analyzed by immunohistochemistry to measure levels of KIT and its ligand KITLG. KIT and/or KITLG was stably knocked down by expression of small hairpin RNAs from lentiviral vectors in DLD1, HT29, LS174T, and COLO320 colon cancer cell lines, and in UM-COLON#8 and POP77 xenografts; cells transduced with only vector were used as controls. Cells were analyzed by real-time quantitative reverse transcription PCR, single-cell gene expression analysis, flow cytometry, and immunohistochemical, immunoblot, and functional assays. Xenograft tumors were grown from control and KIT-knockdown DLD1 and UM-COLON#8 cells in immunocompromised mice and compared. Some mice were given the RTK inhibitor imatinib following injection of cancer cells; tumor growth was measured based on bioluminescence. We assessed tumorigenicity using limiting dilution analysis. KIT and KITLG were expressed heterogeneously by a subset of human colon tumors. Knockdown of KIT decreased proliferation of colon cancer cell lines and growth of xenograft tumors in mice, compared with control cells. KIT knockdown cells had increased expression of enterocyte markers, decreased expression of cycling genes, and, unexpectedly, increased expression of LGR5-associated genes. No activating mutations in KIT were detected in DLD1, POP77, or UM-COLON#8 cell lines. However, KITLG-knockdown DLD1 cells formed smaller xenograft tumors than control cells. Gene expression analysis of single CD44+ cells indicated that KIT may promote growth via KITLG autocrine and/or paracrine signaling. Imatinib inhibited growth of KIT+ colon cancer organoids in culture and growth of xenograft tumors in mice. Cancer cells with endogenous KIT expression were more tumorigenic in mice. KIT and KITLG are expressed by a subset of human colon tumors. KIT signaling promotes growth of colon cancer cells and organoids in culture and xenograft tumors in mice via its ligand, KITLG, in an autocrine or paracrine manner. Patients with KIT-expressing colon tumors may benefit from KIT RTK inhibitors.