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结直肠癌是世界上第三大癌症,居于因癌症死亡的第二位。在我国,结直肠癌居肿瘤发病和死因的第二、五位,且呈现发病率不断上升和发病低龄化的特点[1-2]。结直肠癌早期症状不明显,约50%~60%的结直肠癌患者初诊时就已出现转移,导致了该疾病整体预后不良[3]。研究表明,癌细胞与肿瘤微环境之间的相互作用在肿瘤进展中起着重要作用。其中,癌相关成纤维细胞(cancer-associated fibroblasts, CAFs) 和血管内皮细胞(vascular endothelial cells, VECs)可促进肿瘤细胞生长、侵袭和转移,与多种癌症的不良预后有关[4-5]。肿瘤微环境中的免疫细胞浸润,如肿瘤相关巨噬细胞(tumor associated macrophages, TAMs)和肿瘤浸润淋巴细胞(TILs),也与患者的生存有关[6-7]。免疫疗法作为最有前途的方法已被广泛应用于癌症治疗[8]。因此,探索结直肠癌免疫浸润的预后相关性,寻找新的免疫相关治疗靶点,是结直肠癌早期诊断和治疗的迫切需要。
抑制素βA(inhibitors beta A, INHBA)属于转化生长因子-β(TGF-β)超家族成员,既可以通过同型二聚形成激活素A,也可以通过异型二聚形成抑制素[9-10]。激活素A和抑制素是两种密切相关的糖蛋白,具有相反的生物学效应,广泛参与机体的生殖和发育过程[11]。据报道,INHBA作为激活素A和抑制素的亚单位,在多种癌症中具有促癌或抗癌作用。如在肺癌[12]、胃癌[13]、食管癌[14]和尿路上皮癌[15]等恶性肿瘤中,高水平的INHBA促进肿瘤的侵袭和转移,并与患者的不良预后相关。相反,在弥漫性大B细胞淋巴瘤中INHBA表达明显下调,并发挥肿瘤抑制作用[16]。本文前期研究发现INHBA在结直肠癌的肿瘤芽中高表达,而肿瘤芽是评估结直肠癌预后的指标之一。肿瘤芽的数量越多,肿瘤越容易转移,预后也越差[17]。本文通过数据库挖掘的方法全面分析结直肠癌中INHBA基因的表达和启动子甲基化水平,及其表达与结直肠癌患者预后以及肿瘤微环境中免疫浸润水平、CAFs和VECs浸润水平的相关性。
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利用Oncomine数据库分析INHBA在不同癌症类型中的表达情况,如图1a所示。结果显示,INHBA在膀胱癌、乳腺癌、宫颈癌、结直肠癌、食管癌、胃癌、头颈癌、卵巢癌、胰腺癌和肉瘤中表达高于正常组织,而在肾癌、白血病和黑色素瘤中表达低于正常组织。通过GEPIA进一步测定TCGA和GTEx项目RNA-seq数据中不同癌症类型的INHBA表达情况,如图1b所示。结果显示,INHBA在膀胱移行细胞癌(BLCA)、乳腺浸润癌(BRCA)、结肠腺癌(COAD)、食管癌(ESCA)、头颈部鳞状细胞癌(HNSC)、胰腺癌(PAAD)、直肠腺癌(READ)和胃腺癌(STAD)中相对于正常癌旁组织呈高表达。综上,INHBA在多种恶性肿瘤中表达上调。
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在Oncomine数据库中共找到17项INHBA在结直肠癌中表达增高的数据集,0项表达降低的数据集,如图1a。GEPIA数据库同样显示INHBA在结肠癌和直肠癌中的表达水平都显著高于正常肠黏膜组织(P<0.05),如图2a。通过UALCAN数据库分析INHBA基因启动子的甲基化水平。结果显示,与正常肠黏膜相比,INHBA基因启动子的甲基化水平在结肠腺癌和直肠腺癌中都显著降低,如图2b。这提示INHBA在结直肠癌中表达上调很可能与其基因启动子甲基化水平降低有关。接着分别利用GEPIA和LinkedOmics数据库分析INHBA在结直肠癌不同临床分期中的表达情况,结果都显示INHBA的表达与临床分期呈显著正相关。INHBA在Ⅱ、Ⅲ、Ⅳ期的表达明显高于Ⅰ期,如图2c和2d所示。另外,INHBA的表达与结直肠癌的T和N分期也有明显相关性,INHBA在T1、T2、T3、T4期中的表达量明显高于其在Tis期中的表达,如图2e所示,INHBA在N1和N2期中的表达量明显高于其在N0期中的表达,如图2f所示。这些结果提示INHBA参与促进结直肠癌的生长和转移。
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利用PrognoScan数据库分析了INHBA在结直肠癌患者中的预后价值。结果显示,在采用204926_at和210511_s_at探针的GSE17536数据表中,INHBA高表达组患者总生存期(overall survival, OS)、疾病特异性生存期(disease-specific survival, DSS)和无疾病生存期(disease-free survival, DFS)较INHBA低表达组患者都显著降低,如图3a~图3f所示。在采用204926_at和210511_s_at探针的GSE14333数据表中,INHBA高表达组患者DFS较INHBA低表达组患者也显著降低,如图3g~图3h所示。在采用210511_s_at探针的GSE14333数据表中,INHBA高表达组患者DSS较INHBA低表达组患者同样明显降低,如图3i所示。这表明INHBA高表达与结直肠癌患者预后不良相关。
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通过TIMER数据库分析得到INHBA表达与结肠癌和直肠癌免疫细胞浸润的相关性结果如图4a和图4b所示,可看出INHBA表达水平与细胞纯度有明显相关性。通过纯度校正后,结肠腺癌和直肠腺癌中INHBA表达水平与CD4+T细胞(Cor=0.469,P=2.14×10−23;Cor=0.301,P=3.25×10−4)、巨噬细胞(macrophages)(Cor=0.547,P=6.46×10−33;Cor=0.493,P=7.23×10−10)、中性粒细胞(neutrophils)(Cor=0.581,P=1.43×10−37;Cor=0.406,P=8.02×10−7)、树突状细胞(dendritic cells, DCs)(Cor=0.576,P=7.42×10−37;Cor=0.458,P=1.43×10−8)的浸润水平都呈显著正相关。这表明INHBA在增加结直肠癌微环境中免疫细胞特别是巨噬细胞的浸润方面发挥了重要作用。
同时,利用TIMER数据库分析得出INHBA表达水平与结肠腺癌和结肠腺癌中单核/巨噬细胞(单核细胞、TAMs、M2巨噬细胞)的常见标志物表达显著相关,而与M1巨噬细胞的常见标志物表达微弱相关,如表1所示。通过GEPIA数据库进一步验证发现,正常组织中INHBA表达与单核细胞、TAMs、M1和M2巨噬细胞的常见标志物表达之间的相关性很低,而结直肠癌中INHBA表达与单核细胞、TAMs和M2巨噬细胞免疫标记物表达显著相关如表2。综上,INHBA在结直肠癌中参与调控巨噬细胞的招募和M1/M2极化。
表 1 TIMER中INHBA与单核/巨噬细胞标志物的相关性分析
Description Gene markers COAD READ None Purity None Purity Cor P Cor P Cor P Cor P Monocyte CD115(CSF1R) 0.654 *** 0.610 *** 0.626 *** 0.541 *** CD16(FCGR3A) 0.657 *** 0.628 *** 0.651 *** 0.570 *** CD86 0.643 *** 0.598 *** 0.611 *** 0.524 *** TAM CD11b(ITGAM) 0.664 *** 0.622 *** 0.663 *** 0.595 *** CCL2 0.647 *** 0.590 *** 0.691 *** 0.633 *** CD68 0.538 *** 0.495 *** 0.470 *** 0.400 *** CD80 0.517 *** 0.479 *** 0.469 *** 0.371 *** M1 iNOS(NOS2) −0.087 0.064 −0.120 0.015 −0.145 0.063 −0.164 0.054 IRF5 0.291 *** 0.305 *** 0.283 ** 0.296 ** CXCL10 0.360 *** 0.300 *** 0.337 *** 0.215 0.011 ROS1 0.107 0.021 0.076 0.124 0.150 0.054 0.085 0.318 M2 CD163 0.668 *** 0.630 *** 0.669 *** 0.609 *** VSIG4 0.603 *** 0.547 *** 0.517 *** 0.453 *** MS4A4A 0.577 *** 0.523 *** 0.600 *** 0.529 *** CD206(MRC1) 0.493 *** 0.441 *** 0.501 *** 0.414 *** None, correlation without adjustment; Purity, correlation adjusted for tumor purity; Cor value of Spearman’s correlation. *P < 0.01; **P < 0.001; ***P < 0.0001. 表 2 GEPIA中INHBA与单核/巨噬细胞标志物的相关性分析
Description Gene markers COAD+READ Normal Tumor Cor P Cor P Monocyte CD115(CSF1R) 0.026 0.86 0.73 *** CD16(FCGR3A) 0.00016 1 0.74 *** CD86 0.15 0.28 0.72 *** TAM CD11b(ITGAM) 0.43 * 0.77 *** CCL2 0.53 *** 0.75 *** CD68 −0.2 0.17 0.58 *** CD80 0.091 0.53 0.61 *** M1 macrophage iNOS(NOS2) −0.11 0.44 −0.058 0.27 IRF5 −0.17 0.24 0.35 *** CXCL10 0.054 0.71 0.43 *** ROS1 −0.17 0.23 0.23 *** M2 macrophage CD163 0.18 0.21 0.71 *** VSIG4 0.019 0.89 0.71 *** MS4A4A 0.078 0.59 0.71 *** CD206(MRC1) 0.23 0.098 0.69 *** Tumor, correlation analysis in tumor tissue of TCGA. Normal, correlation analysis in normal colon and rectal tissue of TCGA; Cor value of Spearman’s correlation. *P < 0.01; **P < 0.001; ***P < 0.0001. -
通过TIMER数据库分析得到结肠腺癌和直肠腺癌中INHBA表达水平与CAFs(EPIC计算法:Cor=0.907,P=1.1×10−104;Cor=0.898,P=1.97×10−33。MCP-Counter计算法:Cor=0.892,P=1.84×10−96;Cor=0.833,P=1.48×10−24)和VECs(EPIC计算法:Cor=0.629,P=9.38×10−32;Cor=0.547,P=2.07×10−8。MCP-Counter计算法:Cor=0.731,P=2.44×10−47;Cor=0.712,P=2.69×10−15)的浸润水平都呈显著正相关,如图5所示。同样,利用TIMER数据库分析发现INHBA表达水平与CAFs和VECs的常见标志物表达都高度相关,如表3所示。这些结果都表明INHBA在增加结直肠癌肿瘤微环境中CAFs和VECs的浸润方面也发挥了重要作用。
表 3 TIMER中INHBA与CAFs、VECs标记物的相关性分析
Description Gene marker COAD READ None Purity None Purity Cor P Cor P Cor P Cor P CAF α-SMA(ACTA2) 0.761 *** 0.729 *** 0.724 *** 0.670 *** FAP 0.775 *** 0.761 *** 0.736 *** 0.726 *** Tenascin-C(TNC) 0.809 *** 0.778 *** 0.764 *** 0.707 *** Periostin(POSTN) 0.774 *** 0.748 *** 0.816 *** 0.774 *** PDGFRA 0.608 *** 0.568 *** 0.688 *** 0.616 *** PDGFRB 0.871 *** 0.858 *** 0.885 *** 0.863 *** THY1 0.808 *** 0.781 *** 0.814 *** 0.767 *** Podoplanin(PDPN) 0.777 *** 0.743 *** 0.784 *** 0.723 *** Integrin β1(ITGB1) 0.619 *** 0.594 *** 0.704 *** 0.679 *** Caveolin-1(CAV1) 0.715 *** 0.667 *** 0.767 *** 0.702 *** VEC CD105(ENG) 0.686 *** 0.638 *** 0.641 *** 0.570 *** CD62E(SELE) 0.635 *** 0.604 *** 0.585 *** 0.504 *** CD106(VCAM1) 0.700 *** 0.658 *** 0.762 *** 0.706 *** CD146(MCAM) 0.701 *** 0.661 *** 0.717 *** 0.661 *** None, correlation without adjustment; Purity, correlation adjusted for tumor purity; Cor value of Spearman’s correlation. *P < 0.01; **P < 0.001; ***P < 0.0001.
Expression and Clinical Significance of INHBA in Colorectal Cancer Based on Bioinformatics Databases
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摘要: 抑制素βA作为转化生长因子-β(TGF-β)超家族成员,在不同肿瘤中具有促癌或抗癌作用。通过生物信息数据库分析了INHBA在结直肠癌中的表达水平及临床意义。结果显示INHBA在结直肠癌中明显高表达,且其高表达与结直肠癌的临床分期、T分期和N分期呈正相关。INHBA基因启动子的甲基化水平在结肠腺癌和直肠腺癌中都显著降低。生存分析显示,INHBA高表达的结直肠癌患者预后不良。此外,INHBA表达水平与肿瘤微环境中的绝大多数免疫细胞浸润水平呈正相关,尤其是巨噬细胞。同时,INHBA高表达与癌相关成纤维细胞(CAFs)和血管内皮细胞(VECs)高浸润水平也是密切相关。因此,INHBA在结直肠癌中高表达,参与结直肠癌的进展,有望成为预后和治疗的潜在标志物。Abstract: Inhibitors beta A (INHBA), as a member of transforming growth factor-β (TGF-β) superfamily, have pro-cancer or anti-cancer effects in different tumors. This study aims to investigate the expression and clinical significance of INHBA in colorectal cancer through bioinformatics databases. The results showed that INHBA expression was significantly upregulated in colorectal cancer, and its high expression was positively correlated with clinical stages, T stages and N stages of colorectal cancer. The methylation level of INHBA promoter was significantly reduced in both colon and rectal cancer. Survival analysis showed that colorectal cancer patients with high INHBA expression had poor prognosis. Moreover, INHBA expression was positively correlated with the infiltration levels of most immune cells in the tumor microenvironment, especially macrophages. INHBA high expression was also closely related to the high infiltration levels of cancer-associated fibroblasts (CAFs) and vascular endothelial cells (VECs). Taken together, INHBA is highly expressed in colorectal cancer tissues and involved in the development of colorectal cancer, which is expected to be a potential marker for prognosis and treatment.
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Key words:
- colorectal cancer /
- database /
- INHBA /
- prognosis /
- tumor microenvironment
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表 1 TIMER中INHBA与单核/巨噬细胞标志物的相关性分析
Description Gene markers COAD READ None Purity None Purity Cor P Cor P Cor P Cor P Monocyte CD115(CSF1R) 0.654 *** 0.610 *** 0.626 *** 0.541 *** CD16(FCGR3A) 0.657 *** 0.628 *** 0.651 *** 0.570 *** CD86 0.643 *** 0.598 *** 0.611 *** 0.524 *** TAM CD11b(ITGAM) 0.664 *** 0.622 *** 0.663 *** 0.595 *** CCL2 0.647 *** 0.590 *** 0.691 *** 0.633 *** CD68 0.538 *** 0.495 *** 0.470 *** 0.400 *** CD80 0.517 *** 0.479 *** 0.469 *** 0.371 *** M1 iNOS(NOS2) −0.087 0.064 −0.120 0.015 −0.145 0.063 −0.164 0.054 IRF5 0.291 *** 0.305 *** 0.283 ** 0.296 ** CXCL10 0.360 *** 0.300 *** 0.337 *** 0.215 0.011 ROS1 0.107 0.021 0.076 0.124 0.150 0.054 0.085 0.318 M2 CD163 0.668 *** 0.630 *** 0.669 *** 0.609 *** VSIG4 0.603 *** 0.547 *** 0.517 *** 0.453 *** MS4A4A 0.577 *** 0.523 *** 0.600 *** 0.529 *** CD206(MRC1) 0.493 *** 0.441 *** 0.501 *** 0.414 *** None, correlation without adjustment; Purity, correlation adjusted for tumor purity; Cor value of Spearman’s correlation. *P < 0.01; **P < 0.001; ***P < 0.0001. 表 2 GEPIA中INHBA与单核/巨噬细胞标志物的相关性分析
Description Gene markers COAD+READ Normal Tumor Cor P Cor P Monocyte CD115(CSF1R) 0.026 0.86 0.73 *** CD16(FCGR3A) 0.00016 1 0.74 *** CD86 0.15 0.28 0.72 *** TAM CD11b(ITGAM) 0.43 * 0.77 *** CCL2 0.53 *** 0.75 *** CD68 −0.2 0.17 0.58 *** CD80 0.091 0.53 0.61 *** M1 macrophage iNOS(NOS2) −0.11 0.44 −0.058 0.27 IRF5 −0.17 0.24 0.35 *** CXCL10 0.054 0.71 0.43 *** ROS1 −0.17 0.23 0.23 *** M2 macrophage CD163 0.18 0.21 0.71 *** VSIG4 0.019 0.89 0.71 *** MS4A4A 0.078 0.59 0.71 *** CD206(MRC1) 0.23 0.098 0.69 *** Tumor, correlation analysis in tumor tissue of TCGA. Normal, correlation analysis in normal colon and rectal tissue of TCGA; Cor value of Spearman’s correlation. *P < 0.01; **P < 0.001; ***P < 0.0001. 表 3 TIMER中INHBA与CAFs、VECs标记物的相关性分析
Description Gene marker COAD READ None Purity None Purity Cor P Cor P Cor P Cor P CAF α-SMA(ACTA2) 0.761 *** 0.729 *** 0.724 *** 0.670 *** FAP 0.775 *** 0.761 *** 0.736 *** 0.726 *** Tenascin-C(TNC) 0.809 *** 0.778 *** 0.764 *** 0.707 *** Periostin(POSTN) 0.774 *** 0.748 *** 0.816 *** 0.774 *** PDGFRA 0.608 *** 0.568 *** 0.688 *** 0.616 *** PDGFRB 0.871 *** 0.858 *** 0.885 *** 0.863 *** THY1 0.808 *** 0.781 *** 0.814 *** 0.767 *** Podoplanin(PDPN) 0.777 *** 0.743 *** 0.784 *** 0.723 *** Integrin β1(ITGB1) 0.619 *** 0.594 *** 0.704 *** 0.679 *** Caveolin-1(CAV1) 0.715 *** 0.667 *** 0.767 *** 0.702 *** VEC CD105(ENG) 0.686 *** 0.638 *** 0.641 *** 0.570 *** CD62E(SELE) 0.635 *** 0.604 *** 0.585 *** 0.504 *** CD106(VCAM1) 0.700 *** 0.658 *** 0.762 *** 0.706 *** CD146(MCAM) 0.701 *** 0.661 *** 0.717 *** 0.661 *** None, correlation without adjustment; Purity, correlation adjusted for tumor purity; Cor value of Spearman’s correlation. *P < 0.01; **P < 0.001; ***P < 0.0001. -
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