MicroRNAs 15A and 16-1 Activate Signaling Pathways That Mediate Chemotaxis of Immune Regulatory B cells to Colorectal Tumors
MicroRNAs 15A and 16-1 Activate Signaling Pathways That Mediate Chemotaxis of Immune Regulatory B cells to Colorectal Tumors
复制标题
MicroRNA 15A 和 16-1 激活介导免疫调节 B 细胞向结直肠肿瘤趋化的信号通路。
DOI：
10.1053/j.gastro.2017.09.045
复制
发表时间：
2018-02-01
期刊：
影响因子：
29.4
通讯作者：
Chu, Yiwei
中科院分区：
文献类型：
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作者：
Liu, Ronghua;Lu, Zhou;Chu, Yiwei
背景与目标
B细胞浸润肿瘤，但对它们如何影响肿瘤生长和进展知之甚少。microRNA 15 A（MIR 15 A或miRNA 15 A）和microRNA 16 -1（MIR 16 -1或miRNA 16 -1）调节细胞增殖、凋亡和耐药性。我们研究了它们参与结直肠肿瘤B细胞介导的免疫抑制。
方法
将编码MIR 15 A和MIR 16 -1的基因簇破坏的小鼠（敲除小鼠）和对照（C57 BL/B6）小鼠给予氧化偶氮甲烷和葡聚糖硫酸钠（AD）以诱导结直肠肿瘤的形成。给予小鼠抗CD 20以消除B细胞，或注射阿戈米尔以增加MIR 15 A和MIR 16 -1。通过羧基荧光素-琥珀酰亚胺酯分析测量CD 8 +T细胞的增殖。从小鼠收集结肠组织，并通过流式细胞术、微小RNA（miRNA）测序和细胞因子产生进行分析。分离肠上皮细胞（IEC）并用miRNA模拟物转染，以鉴定它们的靶标。我们分析了2006年7月至2008年4月在中国上海接受手术切除的90例结直肠癌患者的组织微阵列中的miRNA表达模式并定量B细胞;表达数据与临床结果进行了比较。
结果
与对照小鼠中生长的肿瘤相比，给予AD后在敲除小鼠中生长的肿瘤更大，并且含有更多数量的B细胞。肿瘤内大部分B细胞免疫球蛋白A（伊加+）阳性。伊加+ B细胞表达高水平的免疫调节分子（程序性死亡配体1、白细胞介素10和转化生长因子β），并抑制CD 8 + T细胞的增殖和活化。与非肿瘤结肠组织相比，小鼠结肠肿瘤中MIR 15 A和MIR 16 -1的水平降低。IEC与IL 17 A的孵育降低了MIR 15 A和MIR 16 -1的表达。在IEC中转基因表达MIR 15 A和MIR 16 -1通过降低I-κ B激酶的表达降低NF-κB和STAT 1的活化;这导致趋化因子（C-X-C基序）配体9和10的产生减少，伊加+ B细胞的趋化性降低。注射AD和agomir的小鼠的肿瘤比未注射agomir的小鼠的肿瘤生长得更慢，并且含有更少的伊加+ B细胞。我们发现，在人结直肠肿瘤组织中，MIR 15 A和MIR 16 -1的水平与伊加+B细胞的数量之间呈负相关; MIR 15 A和MIR 16 -1的高水平以及伊加+B细胞的低数量与患者的较长生存时间相关。
结论
我们发现增加的MIR 15 A和MIR 16 -1水平减少了结直肠肿瘤组织中伊加+ B细胞的数量，并与患者生存时间的增加相关。在缺乏MIR 15 A和MIR 16 -1的小鼠中，结肠肿瘤生长更快，并且含有增加数量的伊加+ B细胞。MIR 15 A和MIR 16 -1似乎激活B细胞介导的免疫抑制所需的信号通路。
BACKGROUND & AIMS
B cells infiltrate tumors, but little is known about how they affect tumor growth and progression. microRNA15A (MIR15A or miRNA15A) and microRNA16-1 (MIR16-1 or miRNA16-1) regulate cell proliferation, apoptosis, and drug resistance. We investigated their involvement in B-cell-mediated immune suppression by colorectal tumors.
METHODS
Mice with disruptions of the gene cluster that encodes MIR15A and MIR16-1 (knockout mice), and control (C57BL/B6) mice were given azoxymethane with dextran sodium sulfate (AD) to induce formation of colorectal tumors. Mice were given anti-CD20 to delete B cells, or injections of agomir to increase MIR15A and MIR16-1. Proliferation of CD8+T cells was measured by carboxyfluorescein-succinimidyl-ester analysis. Colon tissues were collected from mice and analyzed by flow cytometry, microRNA (miRNA) sequencing, and for cytokine production. Intestinal epithelial cells (IECs) were isolated and transfected with miRNA mimics, to identify their targets. We analyzed miRNA expression patterns and quantified B cells in colorectal cancer tissue microarrays derived from 90 patients who underwent surgical resection, from July 2006 through April 2008, in Shanghai, China; expression data were compared with clinical outcomes.
RESULTS
Tumors that developed in knockout mice following administration of AD were larger and contained greater numbers of B cells than tumors that grew in control mice. Most of the B cells in the tumors were positive for immunoglobulin A (IgA+). IgA+ B cells expressed high levels of immune regulatory molecules (programmed death ligand 1, interleukin 10, and transforming growth factor beta), and repressed the proliferation and activation of CD8+ T cells. Levels of MIR15A and MIR16-1 were reduced in colon tumors from mice, compared with nontumor colon tissue. Incubation of IECs with IL17A reduced expression of MIR15A and MIR16-1. Transgenic expression of MIR15A and MIR16-1 in IECs decreased activation of NF-κB and STAT1 by reducing expression of I-kappaB kinases; this resulted in reduced production of chemokine (C-X-C motif) ligands 9 and 10 and decreased chemotaxis of IgA+ B cells. Tumors in mice injected with AD and agomir grew more slowly than tumors in mice not given in agomir and contained fewer IgA+ B cells. We found a negative correlation between levels of MIR15A and MIR16-1 and numbers of IgA+B cells in human colorectal tumor tissues; high levels of MIR15A and MIR16-1 and low numbers of IgA+B cells were associated with longer survival times of patients.
CONCLUSIONS
We found increased levels of MIR15A and MIR16-1 to reduce numbers of IgA+ B cells in colorectal tumor tissues and correlate with increased survival time of patients. In mice that lack MIR15A and MIR16-1, colon tumors grow more rapidly and contain increased numbers of IgA+ B cells. MIR15A and MIR16-1 appear to activate signaling pathways required for B-cell-mediated immune suppression.