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1.
T cell Ig and ITIM domain (TIGIT) is a newly identified receptor expressed on T cells that binds to CD155 on the dendritic cell surface, driving them to a more tolerogenic phenotype. Given that TIGIT contains an ITIM motif in its intracellular domain and considering the potential importance of the TIGIT/CD226 pathway in human autoimmune disease, we investigated the specific role of TIGIT in human CD4(+) T cells. Using an agonistic anti-TIGIT mAb, we demonstrate a direct inhibitory effect on T cell proliferation with a decrease in expression of T-bet, GATA3, IFN regulatory factor 4, and retinoic acid-related orphan receptor c with inhibition of cytokine production, predominantly IFN-γ. Knockdown of TIGIT expression by short hairpin RNA resulted in an increase of both T-bet and IFN-γ mRNA and protein expression with concomitant decrease in IL-10 expression. Increases in IFN-γ with TIGIT knockdown could be overcome by blocking CD226 signaling, indicating that TIGIT exerts immunosuppressive effects by competing with CD226 for the same CD155 ligand. These data demonstrate that TIGIT can inhibit T cell functions by competing with CD226 and can also directly inhibit T cells in a T cell-intrinsic manner. Our results provide evidence for a novel role of this alternative costimulatory pathway in regulating human T cell responses associated with autoimmune disease.  相似文献   

2.
CD155 (poliovirus receptor) localizes in cell-matrix adhesions and cell-cell junctions, but its role in the regulation of cell adhesion and cell motility has not been investigated. We identified a conserved immunoreceptor tyrosine-based inhibitory motif (ITIM) in the cytoplasmic domain of human CD155alpha. The ITIM was tyrosine-phosphorylated upon binding of anti-CD155 monoclonal antibody D171, poliovirus, and DNAM-1 (CD226) to human CD155alpha, and recruited SH2-domain-containing tyrosine phosphatase-2 (SHP-2). After CD155alpha stimulation with its ligands, cell adhesion was inhibited and cell motility was enhanced, effects that were associated with the phosphorylation of ITIM by Src kinases and accompanied by dephosphorylation of focal adhesion kinase and paxillin. These effects were abolished by introducing a point-mutation in Y398F into the ITIM of CD155alpha and by coexpression of a dominant negative SHP-2 mutant with CD155alpha. These results suggest that CD155alpha plays a role in the regulation of cell adhesion and cell motility.  相似文献   

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Cutting edge: TIGIT has T cell-intrinsic inhibitory functions   总被引:1,自引:0,他引:1  
Costimulatory molecules regulate the functional outcome of T cell activation, and disturbance of the balance between activating and inhibitory signals results in increased susceptibility to infection or the induction of autoimmunity. Similar to the well-characterized CD28/CTLA-4 costimulatory pathway, a newly emerging pathway consisting of CD226 and T cell Ig and ITIM domain (TIGIT) has been associated with susceptibility to multiple autoimmune diseases. In this study, we examined the role of the putative coinhibitory molecule TIGIT and show that loss of TIGIT in mice results in hyperproliferative T cell responses and increased susceptibility to autoimmunity. TIGIT is thought to indirectly inhibit T cell responses by the induction of tolerogenic dendritic cells. By generating an agonistic anti-TIGIT Ab, we demonstrate that TIGIT can inhibit T cell responses directly independent of APCs. Microarray analysis of T cells stimulated with agonistic anti-TIGIT Ab revealed that TIGIT can act directly on T cells by attenuating TCR-driven activation signals.  相似文献   

5.
CD155, one of the nectin‐like molecule family members, is involved in cell adhesion and motility. CD155 is overexpressed in several human cancers, but its role in proliferation and apoptosis of colorectal cancer remains unclear. We found that CD155 was up‐regulated in colorectal cancer tissues. CD155 knockdown via shRNA lentiviruses inhibited colon cancers cell migration and invasion, with a reduction in the expression of FAK, Src and MMP‐2. CD155 down‐regulation also suppressed colon cancer cell proliferation, accompanied by changing expressions of some molecules related to cell cycle. Finally, CD155 knockdown increased the expression ratio between Bax and Bcl‐2, resulting in a significant increase in colon cancer cell apoptosis. Taken together, these results demonstrate that CD155 is involved in not only migration and invasion but also proliferation and survival abilities of colon cancer cells, suggesting that CD155 is one of key molecules promoting the growth and metastasis of colorectal cancer.  相似文献   

6.
Activating and inhibitory receptors control natural killer (NK) cell activity. T-cell immunoglobulin and ITIM (immunoreceptor tyrosine-based inhibition motif) domain (TIGIT) was recently identified as a new inhibitory receptor on T and NK cells that suppressed their effector functions. TIGIT harbors the immunoreceptor tail tyrosine (ITT)-like and ITIM motifs in its cytoplasmic tail. However, how its ITT-like motif functions in TIGIT-mediated negative signaling is still unclear. Here, we show that TIGIT/PVR (poliovirus receptor) engagement disrupts granule polarization leading to loss of killing activity of NK cells. The ITT-like motif of TIGIT has a major role in its negative signaling. After TIGIT/PVR ligation, the ITT-like motif is phosphorylated at Tyr225 and binds to cytosolic adapter Grb2, which can recruit SHIP1 to prematurely terminate phosphatidylinositol 3-kinase (PI3K) and MAPK signaling, leading to downregulation of NK cell function. In support of this, Tyr225 or Asn227 mutation leads to restoration of TIGIT/PVR-mediated cytotoxicity, and SHIP1 silencing can dramatically abolish TIGIT/PVR-mediated killing inhibition.  相似文献   

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8.
In recent years, restoring anti-tumor immunity has garnered a growing interest in cancer treatment. As potential therapeutics, immune checkpoint inhibitors have demonstrated benefits in many clinical studies. Although various methods have been applied to suppress immune checkpoints to boost anti-tumor immunity, including the use of immune checkpoint inhibitors, there are still unmet clinical needs to improve the response rate of cancer treatment. Here, we show that acetate can suppress the expression of poliovirus receptor (PVR/CD155), a ligand for immune checkpoint, in colon cancer cells. We demonstrated that acetate treatment could enhance effector responses of CD8+ T cells by decreasing the expression of PVR/CD155 in cancer cells. We also found that acetate could reduce the expression of PVR/CD155 by deactivating the PI3K/AKT pathway. These results demonstrate that acetate-mediated expression of PVR/CD155 in cancer cells might potentiate the anti-tumor immunity in the microenvironment of cancer. Our findings indicate that maintaining particular acetate concentrations could be a complementary strategy in current cancer treatment.  相似文献   

9.
Pathological assessment of excised tumour and surgical margins in colorectal cancer (CRC) play crucial role in prognosis after surgery. Molecular assessment of margins could be more sensitive and informative than conventional histopathological analysis. Considering this view, we evaluated the distal surgical margins for expression of cancer stem cell (CSC) markers. Cellular and molecular assessment of normal, tumour and distal margin tissues were performed by flow cytometry, real‐time q‐PCR and immuno‐histochemical analysis for CRC patients after tumour excision. CRC patients were evaluated for expression of CSC markers in their normal, tumour and distal tissues. Flow cytometry assay revealed CD133 and CD44 enriched cells in distal margin and tumour compared to normal colorectal tissues, which was further confirmed by immunohistochemistry. Most importantly, immunohistochemistry also revealed the enrichment of CSC markers expression in pathologically negative distal margins. Patients with distal margin enriched for CD133 expression showed an increased recurrence rate and decreased disease‐free survival. This study proposes that although distal margin seems to be tumour free in conventional histopathological analysis, it could harbour cells enriched for CSC markers. Further CD133 could be a promising molecule to be used in molecular pathology for disease prognosis after surgery in CRC patients.  相似文献   

10.
The aberrant expression of human sirtuin 2 (SIRT2) has been detected in various types of cancer; however, the biological roles, underlying mechanisms and clinical significance of SIRT2 dysregulation in human colorectal cancer (CRC) remain unclear. The results of this study demonstrate that compared with paired normal tissues, SIRT2 expression is significantly decreased in CRC tissues. SIRT2 loss has been correlated with clinicopathological characteristics, including distant metastasis, lymph node metastasis and American Joint Committee on Cancer (AJCC) stage; this loss serves as an independent factor that indicates a poor prognosis for patients with CRC. Further gain‐ and loss‐of‐function analyses have demonstrated that SIRT2 suppresses CRC cell proliferation and metastasis both in vivo and in vitro. Mechanistically, miR‐212‐5p was identified to directly target the SIRT2 3′‐untranslated region (3′‐UTR), leading to SIRT2 down‐regulation. The ectopic expression of SIRT2 reverses the effect of miR‐212‐5p overexpression on CRC cell colony formation, invasion, migration and proliferation. Clinically, an inverse correlation was found between miR‐212‐5p and SIRT2 expression. High miR‐212‐5p expression has been found to result in a poor prognosis and aggressive clinicopathological characteristics in patients with CRC. Taken together, these results suggest that SIRT2, targeted by miR‐212‐5p, acts as a tumour suppressor in CRC and that the miR‐212‐5p/SIRT2 axis is a promising prognostic factor and potential therapeutic target in CRC.  相似文献   

11.
T细胞免疫球蛋白和免疫受体酪氨酸抑制性基序结构域\[T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain,TIGIT\]是一种新型的免疫抑制性受体,在机体的免疫调节网络中扮演着重要角色。为了进一步探究TIGIT对自然杀伤(natural killer,NK)细胞的免疫调节功能,构建了融合蛋白TIGIT胞外段(即TIGIT第1~135位氨基酸,以保留功能结构域IgV区,此胞外段简称为TIG)-人免疫球蛋白G3(immunoglobulin G3,IgG3)Fc段的真核表达载体,并对TIG-Fc融合蛋白的表达及其对NK-92细胞功能的影响进行了初步研究。利用分子生物学方法,将携带人TIG与人IgG3 Fc段的基因融合,然后插入真核表达载体pcDNA3.1(-)中,以构建重组质粒pcDNA3.1(-)-TIG-Fc。随后将重组质粒转染至人胚肾细胞HEK-293T中,通过流式细胞仪和Western blot检测TIG-Fc融合蛋白在293T细胞中的表达;再将重组质粒转染至NK-92细胞中,通过WST-1检测TIG-Fc融合蛋白对NK-92细胞增殖的影响,并利用ELISA法检测TIG-Fc融合蛋白对NK-92细胞分泌IFN-γ的水平的影响。结果成功构建了人TIG与人IgG3 Fc融合表达的真核表达载体,且TIG-Fc融合蛋白的表达能够显著抑制NK-92细胞的增殖和分泌IFN-γ的能力(P<0.05),为后期TIGIT的功能研究奠定了重要基础。  相似文献   

12.
Natural killer (NK) cell activation is well orchestrated by a wide array of NK cell receptor repertoire. T-cell immunoglobulin and ITIM domain (TIGIT) receptor was recently defined as an inhibitory receptor that is expressed on NK cells and T cells. TIGIT receptor/poliovirus receptor (PVR) ligand engagement signaling inhibits cytotoxicity mediated by NK and CD8+ T cells. However, it is unclear how TIGIT/PVR signaling regulates cytokine secretion in NK cells. Here we show that TIGIT/PVR engagement suppresses interferon-γ (IFN-γ) production of NK cells. TIGIT transgenic NK cells generate less IFN-γ undergoing TIGIT/PVR ligation. Moreover, TIGIT knock-out NK cells produce much more IFN-γ. TIGIT/PVR ligation signaling mediates suppression of IFN-γ production via the NF-κB pathway. We identified a novel adaptor β-arrestin 2 that associates with phosphorylated TIGIT for further recruitment of SHIP1 (SH2-containing inositol phosphatase 1) through the ITT-like motif. Importantly, SHIP1, but not other phosphatases, impairs the TNF receptor-associated factor 6 (TRAF6) autoubiquitination to abolish NF-κB activation, leading to suppression of IFN-γ production in NK cells.  相似文献   

13.
CD72是一个重要的B细胞特异性受体,它以多种选择性剪切形式存在.在小鼠脾细胞中发现并鉴定了8种新的CD72选择性剪切形式,这些剪切形式中包含有2种独特的插入片段,一种选择性剪切保留了一个内含子(intron1),而这个内含子被翻译成氨基酸序列后并没有改变前后外显子的读码框,另一种使用了一个位于内含子之内的3′剪切位点,从而产生移码,提前终止了蛋白质的开放读码框,称为3′AS(3′alternative splicingsite).比较了CD72所有剪切形式在BALB/C小鼠和NZB/W小鼠中的差异表达,发现:a.含有3′AS的剪切形式的表达都很少;b.WT, In1, In1-Ex3和-Ex3的表达在BLAB/C小鼠中比在NZB/W小鼠中高;c.没有ITIM2的-Ex2-Ex3剪切形式在NZB/W小鼠中有特异性高表达.这些结果提示,CD72的多种选择性剪切形式在调控B细胞受体信号转导过程中可能发挥着不同的作用,并与系统性红斑狼疮的发病密切相关.  相似文献   

14.
The current prognosis and classification of CRC relies on staging systems that integrate histopathologic and clinical findings. However, in the majority of CRC cases, cell dysfunction is the result of numerous mutations that modify protein expression and post-translational modification1.A number of cell surface antigens, including cluster of differentiation (CD) antigens, have been identified as potential prognostic or metastatic biomarkers in CRC. These antigens make ideal biomarkers as their expression often changes with tumour progression or interactions with other cell types, such as tumour-infiltrating lymphocytes (TILs) and tumour-associated macrophages (TAMs).The use of immunohistochemistry (IHC) for cancer sub-classification and prognostication is well established for some tumour types2,3. However, no single ‘marker’ has shown prognostic significance greater than clinico-pathological staging or gained wide acceptance for use in routine pathology reporting of all CRC cases. A more recent approach to prognostic stratification of disease phenotypes relies on surface protein profiles using multiple ''markers''. While expression profiling of tumours using proteomic techniques such as iTRAQ is a powerful tool for the discovery of biomarkers4, it is not optimal for routine use in diagnostic laboratories and cannot distinguish different cell types in a mixed population. In addition, large amounts of tumour tissue are required for the profiling of purified plasma membrane glycoproteins by these methods. In this video we described a simple method for surface proteome profiling of viable cells from disaggregated CRC samples using a DotScan CRC antibody microarray. The 122-antibody microarray consists of a standard 82-antibody region recognizing a range of lineage-specific leukocyte markers, adhesion molecules, receptors and markers of inflammation and immune response5, together with a satellite region for detection of 40 potentially prognostic markers for CRC. Cells are captured only on antibodies for which they express the corresponding antigen. The cell density per dot, determined by optical scanning, reflects the proportion of cells expressing that antigen, the level of expression of the antigen and affinity of the antibody6. For CRC tissue or normal intestinal mucosa, optical scans reflect the immunophenotype of mixed populations of cells. Fluorescence multiplexing can then be used to profile selected sub-populations of cells of interest captured on the array. For example, Alexa 647-anti-epithelial cell adhesion molecule (EpCAM; CD326), is a pan-epithelial differentiation antigen that was used to detect CRC cells and also epithelial cells of normal intestinal mucosa, while Phycoerythrin-anti-CD3, was used to detect infiltrating T-cells7. The DotScan CRC microarray should be the prototype for a diagnostic alternative to the anatomically-based CRC staging system.  相似文献   

15.
Graft-versus-host disease (GVHD) is the most common complication and major limitation of allogeneic hematopoietic stem cell transplantation. The CD226/TIGIT-CD155 signal is critical for the cross-talk between T cells and dendritic cells (DCs). Studies have shown that blockade of the CD226-CD155 interaction, using an anti-CD226 antibody, can significantly ameliorate GVHD. It has also been reported that a TIGIT-Fc fusion protein exerts immunosuppressive effects by binding to CD155 on DCs. Here, we used a mouse allogeneic acute GVHD model to explore the therapeutic potential and mechanism of action of TIGIT-Fc. C57/BL6 and Balb/c mice were used as hematopoietic cell graft donors and recipients, respectively. In the TIGIT-Fc-treated mice, GVHD symptom occurrence and mortality were delayed compared to that in isotype control group mice. Histopathological analyses revealed that following TIGIT-Fc treatment, liver and small intestine tissue damage was reduced with minimal lymphocytic infiltration. The percentage of CD8+IFN-γ+ and CD8+ granzyme B+ cells significantly decreased in the TIGIT-Fc group. Moreover, treatment with TIGIT-Fc, even after the onset of GVHD, ameliorated symptoms and prolonged survival. TIGIT-Fc also inhibited CD8+ T cell activation in vitro; this was dependent on the presence of CD155 on bone marrow-derived dendritic cells (BMDCs) and on IL-10 production. In addition, TIGIT–CD155 ligation triggered both Erk phosphorylation and STAT3 nuclear translocation. These data indicate that TIGIT plays an important role in the development of GVHD and is an ideal molecular target to treat acute GVHD.  相似文献   

16.
Human T-cell leukemia virus type 1 (HTLV-1) infects CD4+ T cells and induces proliferation of infected cells in vivo, which leads to the onset of adult T-cell leukemia (ATL) in some infected individuals. The HTLV-1 bZIP factor (HBZ) gene, which is encoded in the minus strand of HTLV-1, plays critical roles in pathogenesis. In this study, RNA-seq and ChIP-seq analyses using HBZ transduced T cells revealed that HBZ upregulates the expression and promoter acetylation levels of a co-inhibitory molecule, T cell immunoglobulin and ITIM domain (TIGIT), in addition to those of regulatory T cells related genes, Foxp3 and Ccr4. TIGIT was expressed on CD4+ T cells from HBZ-transgenic (HBZ-Tg) mice, and on ATL cells and HTLV-1 infected CD4+ T cells of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in vivo. Expression of Blimp1 and IL-10 was upregulated in TIGIT+CD4+ cells of HBZ-Tg mice compared with TIGIT-CD4+ T cells, suggesting the correlation between TIGIT expression and IL-10 production. When CD4+ T cells from HBZ-Tg mice were stimulated with TIGIT’s ligand, CD155, their production of the inhibitory cytokine IL-10 was enhanced. Furthermore, dendritic cells from HBZ-Tg mice produced high levels of IL-10 after stimulation. These data suggest that HBZ alters immune system to suppressive state via TIGIT and IL-10. Importantly, TIGIT suppressed T-cell responses to another HTLV-1 virus protein, Tax, in vitro. Blocking of TIGIT and PD-1 slightly increased anti-Tax T-cell activity in some HAM/TSP patients. These results suggest that HBZ-induced TIGIT on HTLV-1 infected cells impairs T-cell responses to viral antigens. This study shows that HBZ-induced TIGIT plays a pivotal role in attenuating host immune responses and shaping a microenvironment favorable to HTLV-1.  相似文献   

17.
Colorectal cancer (CRC) remains both common and fatal, and its successful treatment is greatly limited by the development of stem cell‐like characteristics (stemness) and chemoresistance. MiR‐30‐5p has been shown to function as a tumor suppressor by targeting the Wnt/β‐catenin signaling pathway, but its activity in CRC has never been assessed. We hypothesized that miR‐30‐5p exerts anti‐oncogenic effects in CRC by regulating the USP22/Wnt/β‐catenin signaling axis. In the present study, we demonstrate that tissues from CRC patients and human CRC cell lines show significantly decreased miR‐30‐5p family expression. After identifying the 3’UTR of USP22 as a potential binding site of miR‐30‐5p, we constructed a luciferase reporter containing the potential miR‐30‐5p binding site and measured the effects on USP22 expression. Western blot assays showed that miR‐30‐5p decreased USP22 protein expression in HEK293 and Caco2 CRC cells. To evaluate the effects of miR‐30‐5p on CRC cell stemness, we isolated CD133 + CRC cells (Caco2 and HCT15). We then determined that, while miR‐30‐5p is normally decreased in CD133 + CRC cells, miR‐30‐5p overexpression significantly reduces expression of stem cell markers CD133 and Sox2, sphere formation, and cell proliferation. Similarly, we found that miR‐30‐5p expression is normally reduced in 5‐fluorouracil (5‐FU) resistant CRC cells, whereas miR‐30‐5p overexpression in 5‐FU resistant cells reduces sphere formation and cell viability. Inhibition of miR‐30‐5p reversed the process. Finally, we determined that miR‐30‐5p attenuates the expression of Wnt/β‐catenin signaling target genes (Axin2 and MYC), Wnt luciferase activity, and β‐catenin protein levels in CRC stem cells.  相似文献   

18.
Cosmc is known as a T‐synthase‐specific molecular chaperone that plays a crucial role in the process of O‐glycosylation. Cosmc dysfunction leads to inactive T‐synthase and results in aberrant O‐glycosylation, which is associated with various tumour malignancies. However, it is unclear whether Cosmc has some other functions beyond its involvement in O‐glycosylation. In this study, we aimed to investigate the functional role of Cosmc in human colorectal cancer (CRC). We first assessed the expression levels of Cosmc in human CRC specimens and then forcedly expressed Cosmc in human CRC cell lines (HCT116, SW480) to examine its impact on cellular behaviours. The mechanisms for aberrant expression of Cosmc in CRC tissues and the altered behaviours of tumour cells were explored. It showed that the mRNA and protein levels of Cosmc were markedly elevated in human CRC specimens relative to normal colorectal tissues. The occurrence of endoplasmic reticulum (ER) stress may largely contribute to the increased Cosmc expression in cancer tissue and cells. Cosmc overexpression in CRC cells significantly promoted cell migration and invasion, which could be attributed to the activation of the epithelial‐mesenchymal transition (EMT) pathway rather than aberrant O‐glycosylation. These data indicate that Cosmc expression was elevated in human CRC possibly caused by ER stress, which further enhanced malignancies through the activation of EMT but independently of aberrant O‐glycosylation.  相似文献   

19.
Breast cancer stem cells (BCSCs) have been considered responsible for cancer progression, recurrence, metastasis and drug resistance. However, the mechanisms by which cells acquire self‐renewal and chemoresistance properties are remaining largely unclear. Herein, we evaluated the role of miR‐708 and metformin in BCSCs, and found that the expression of miR‐708 is significantly down‐regulated in BCSCs and tumour tissues, and correlates with chemotherapy response and prognosis. Moreover, miR‐708 markedly inhibits sphere formation, CD44+/CD24? ratio, and tumour initiation and increases chemosensitivity of BCSCs. Mechanistically, miR‐708 directly binds to cluster of differentiation 47 (CD47), and regulates tumour‐associated macrophage‐mediated phagocytosis. On the other hand, CD47 is essential for self‐renewal, tumour initiation and chemoresistance of BCSCs, and correlates with the prognosis of breast cancer patients. In addition, the anti‐type II diabetes drug metformin are found to be involved in the miR‐708/CD47 signalling pathway. Therefore, our study demonstrated that miR‐708 plays an important tumour suppressor role in BCSCs self‐renewal and chemoresistance, and the miR‐708/CD47 regulatory axis may represent a novel therapeutic mechanism of metformin in BCSCs.  相似文献   

20.
Colorectal cancer is one of the most common cancers. Regorafenib is used in patients with metastatic colorectal cancer and sometimes, the cancer cells become resistant to the drug. However, increased IGF-1R activity is associated with the invasion of cancer cells. Therefore, it is thought that inhibiting IGF-1R by Linsitinib and Aspirin, the resistance of colorectal cancer cells to Regorafenib can be reduced.SW48 colon cancer cell line was cultured, resistance to the regorafenib and exposed to Linsitinib and Aspirin. The treatment cytotoxicity, Flow cytometry for determine cancer stem cell markers, and the mRNA expression of CD133, CD44, CD24, IGF1-R, CDX2 and PTEN were done. Then C57BL/6J mice tumor model was produced and treated with regorafenib, aspirin, and linsitinib. At least, Clinical symptoms, the levels of IL-6, and IL-1β, TNF-α and MCP-1 in the colon tissues and sera were assessed.The linsitinib and aspirin as the IGF1-R antagonists inhibited colon cancer resistance against regorafenib, stem-cell like colon cancer cells growth, decreased expression of CD133, CD44, CD24, and also increased CDX2, PTEN gene expression. In the canceroous mice, linsitinib, aspirin and regorafenib treatment enhanced Body weight and survival, and also decreased fecal blood, number of tumors in colon and Inflammatory cytokines levels in serum and colon tissues.In this study, we obtained the best in-vitro and in-vivo result of colon cancer treatment when combinitation therapy Linsitinib, Aspirin, and Regorafenib was used, and could prevent tumor resistance, stem cell producing, pathological interaction and disease activity index.  相似文献   

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