MMR, mismatch repair

MMR,不匹配修复
  • 文章类型: Journal Article
    免疫检查点阻断疗法已经深刻地彻底改变了癌症免疫治疗领域。然而,尽管对各种癌症有很大的希望,免疫检查点抑制剂在结直肠癌(CRC)中的疗效仍然较低.这主要是由于肿瘤微环境(TME)的免疫抑制特征。新的证据表明,某些化疗药物诱导免疫原性细胞死亡(ICD),显示出重塑免疫抑制TME的巨大潜力。在这项研究中,使用体外和体内实验方法证实了人参皂苷Rg3(Rg3)作为针对CRC细胞的ICD诱导物的潜力。槲皮素(QTN)可引起活性氧(ROS),从而显着增强Rg3的ICD功效。为了改善与化疗药物相关的体内递送障碍,开发了叶酸(FA)靶向的聚乙二醇(PEG)修饰的两亲性环糊精纳米颗粒(NP)用于Rg3和QTN的共封装。得到的纳米制剂(CD-PEG-FA.Rg3.QTN)在原位CRC小鼠模型中显着延长了血液循环并增强了肿瘤靶向,导致免疫抑制TME的转化。此外,CD-PEG-FA。Rg3.QTN与抗PD-L1组合实现了动物的显著更长的存活。该研究为CRC的治疗提供了有希望的策略。
    The immune checkpoint blockade therapy has profoundly revolutionized the field of cancer immunotherapy. However, despite great promise for a variety of cancers, the efficacy of immune checkpoint inhibitors is still low in colorectal cancer (CRC). This is mainly due to the immunosuppressive feature of the tumor microenvironment (TME). Emerging evidence reveals that certain chemotherapeutic drugs induce immunogenic cell death (ICD), demonstrating great potential for remodeling the immunosuppressive TME. In this study, the potential of ginsenoside Rg3 (Rg3) as an ICD inducer against CRC cells was confirmed using in vitro and in vivo experimental approaches. The ICD efficacy of Rg3 could be significantly enhanced by quercetin (QTN) that elicited reactive oxygen species (ROS). To ameliorate in vivo delivery barriers associated with chemotherapeutic drugs, a folate (FA)-targeted polyethylene glycol (PEG)-modified amphiphilic cyclodextrin nanoparticle (NP) was developed for co-encapsulation of Rg3 and QTN. The resultant nanoformulation (CD-PEG-FA.Rg3.QTN) significantly prolonged blood circulation and enhanced tumor targeting in an orthotopic CRC mouse model, resulting in the conversion of immunosuppressive TME. Furthermore, the CD-PEG-FA.Rg3.QTN achieved significantly longer survival of animals in combination with Anti-PD-L1. The study provides a promising strategy for the treatment of CRC.
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  • 文章类型: Journal Article
    以蛋白酶体抑制剂为代表的多发性骨髓瘤的新治疗方法,免疫调节药物和单克隆抗体产生了深刻的反响。然而,复发是可能的,所有种类的药物对患者都是难以治疗的。下一代测序提高了我们对与耐药性相关的多发性骨髓瘤基因组的理解,并发现了许多基因组变异。因此,本研究采用新一代全外显子组测序技术,对硼替佐米方案和达雷妥单抗治疗复发和难治性MM患者的耐药相关新变异进行研究.从6例患者的EDTA管中收集外周血样本;其中4例复发且对硼替佐米方案和达拉图单抗无效;两名患者对硼替佐米方案有反应。通过MGI-DNBSEQ-G400仪器进行全外显子组测序。我们在多发性骨髓瘤患者中鉴定出21种变异。在11个基因的复发性和难治性多发性骨髓瘤中发现了17个变异(GNAQ,PMS1,CREB1,NSUNS2,PIK3CG,ROS1,PMS2,FIT4,KDM5A,STK11和ZFHX3)。在4个基因(RAF1,CREB1,ZFHX3和INSR)中对硼替佐米方案有反应的两名患者中发现了四种变异。我们已经观察到许多基因中的几种遗传变异,这些基因可能与这些患者的不良预后和对治疗的不良反应有关。这些值应该在使用RNA-seq技术鉴定基因组表达的大样本研究中进一步证实。
    Novel treatment in multiple myeloma represented by proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies have produced a deep response. However, relapses are possible, and all classes of drugs are refractory to patients. Next-generation sequencing has improved our understanding of the multiple myeloma genome related to drug resistance and has discovered many genomic variants. Therefore, this study was conducted to investigate new variants associated with drug resistance in MM patients who relapsed and refractory to bortezomib regimen and daratumumab treatment using next-generation sequencing for whole-exome sequencing. Peripheral blood samples were collected in EDTA tubes from six patients; four were in relapsed and refractory to bortezomib regimens and daratumumab; two patients responded to bortezomib regimens. Whole-exome sequencing was performed by the MGI-DNBSEQ-G400 instrument. We identified 21 variants in multiple myeloma patients. Seventeen variants were found in relapsed and refractory multiple myeloma in 11 genes (GNAQ, PMS1, CREB1, NSUNS2, PIK3CG, ROS1, PMS2, FIT4, KDM5A, STK11 and ZFHX3). And four variants were identified in two patients with response to bortezomib regimens in 4 genes (RAF1, CREB1, ZFHX3 and INSR). We have observed several genetic variants in many genes that may have been associated with the poor prognosis and poor response to treatment in these patients. These values should be further confirmed in large sample studies using the RNA-seq technique to identify genome expression.
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  • 文章类型: Journal Article
    人工智能(AI)是一个通用术语,是指使用机器来模仿智能行为,以最少的人为干预来执行复杂的任务。比如机器学习;这项技术正在彻底改变和重塑医学。人工智能在诊断等领域具有完善医疗保健系统的巨大潜力,风险分析,卫生信息管理,生活方式监督,虚拟健康援助。在免疫治疗方面,人工智能已被应用于基于免疫特征的免疫治疗反应的预测,医学成像和组织学分析。这些特征在癌症免疫疗法的管理中也非常有用,因为它们在提高诊断准确性方面的性能不断提高。优化治疗计划,预测护理结果并降低人力资源成本。在这次审查中,我们介绍了AI的详细信息以及将AI用于癌症免疫治疗的当前进展和最新技术。此外,我们讨论挑战,应用该技术进行广泛临床部署的机会和相应的策略。最后,我们总结了AI对癌症免疫治疗的影响,并提供了我们对未来AI潜在应用的看法。
    Artificial intelligence (AI) is a general term that refers to the use of a machine to imitate intelligent behavior for performing complex tasks with minimal human intervention, such as machine learning; this technology is revolutionizing and reshaping medicine. AI has considerable potential to perfect health-care systems in areas such as diagnostics, risk analysis, health information administration, lifestyle supervision, and virtual health assistance. In terms of immunotherapy, AI has been applied to the prediction of immunotherapy responses based on immune signatures, medical imaging and histological analysis. These features could also be highly useful in the management of cancer immunotherapy given their ever-increasing performance in improving diagnostic accuracy, optimizing treatment planning, predicting outcomes of care and reducing human resource costs. In this review, we present the details of AI and the current progression and state of the art in employing AI for cancer immunotherapy. Furthermore, we discuss the challenges, opportunities and corresponding strategies in applying the technology for widespread clinical deployment. Finally, we summarize the impact of AI on cancer immunotherapy and provide our perspectives about underlying applications of AI in the future.
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  • 文章类型: Journal Article
    基因组不稳定性仍然是癌症的有利特征,并促进恶性转化。DNA损伤反应(DDR)途径的改变允许基因组不稳定,产生新抗原,上调程序性死亡配体1(PD-L1)的表达,并与信号传导如干扰素基因的环GMP-AMP合酶-刺激物(cGAS-STING)信号传导相互作用。这里,我们回顾了DDR途径的基本知识,DDR改变引起的基因组不稳定性的机制,DDR改变对免疫系统的影响,以及DDR改变作为生物标志物和治疗靶点在癌症免疫治疗中的潜在应用。
    Genomic instability remains an enabling feature of cancer and promotes malignant transformation. Alterations of DNA damage response (DDR) pathways allow genomic instability, generate neoantigens, upregulate the expression of programmed death ligand 1 (PD-L1) and interact with signaling such as cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling. Here, we review the basic knowledge of DDR pathways, mechanisms of genomic instability induced by DDR alterations, impacts of DDR alterations on immune system, and the potential applications of DDR alterations as biomarkers and therapeutic targets in cancer immunotherapy.
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  • 文章类型: Journal Article
    最近的研究表明,癌症是由于肿瘤DNA中驱动体细胞事件的阳性选择而产生的,负面选择只扮演次要角色,如果有的话。然而,这些研究涉及非重复序列的改变,没有考虑在本研究中研究的显示错配修复缺陷导致的微卫星不稳定性(MSI)的肿瘤中具有非常高的病理生理相关性的重复序列中的突变.
    我们对47例MSI结直肠癌(CRC)进行了全外显子组测序,并在53例MSICRC的独立队列中证实了结果。我们使用了微卫星内突变事件的概率模型,同时调整预先存在的模型来分析非重复DNA序列。研究了MSICRC中的阴性选择的编码改变在CRC细胞系和164名MSICRC患者的第三组中的功能和临床影响。
    观察到DNA重复序列中体细胞突变的阳性和阴性选择,引导我们确定与MSI驱动的致瘤过程相关的预期真正的驱动基因。几个编码负选择的MSI相关突变事件(n=5)显示对肿瘤细胞具有有害作用。在尽管阴性选择仍观察到有害MSI突变的肿瘤中,它们与MSICRC患者的生存率较差相关(风险比,3;95%CI,1.1-7.9;P=0.03),提示它们的抗癌作用应被其他未知的致癌过程所抵消,这些过程会导致预后不良。
    本结果确定了在MSI驱动的肿瘤发生中起作用的阳性和阴性驱动体细胞突变,表明MSICRC中的基因组不稳定性在实现肿瘤细胞转化中起着双重作用。外显子组测序数据已保存在欧洲基因组-表型档案中(登录号:EGAS00001002477)。
    Recent studies have shown that cancers arise as a result of the positive selection of driver somatic events in tumor DNA, with negative selection playing only a minor role, if any. However, these investigations were concerned with alterations at nonrepetitive sequences and did not take into account mutations in repetitive sequences that have very high pathophysiological relevance in the tumors showing microsatellite instability (MSI) resulting from mismatch repair deficiency investigated in the present study.
    We performed whole-exome sequencing of 47 MSI colorectal cancers (CRCs) and confirmed results in an independent cohort of 53 MSI CRCs. We used a probabilistic model of mutational events within microsatellites, while adapting pre-existing models to analyze nonrepetitive DNA sequences. Negatively selected coding alterations in MSI CRCs were investigated for their functional and clinical impact in CRC cell lines and in a third cohort of 164 MSI CRC patients.
    Both positive and negative selection of somatic mutations in DNA repeats was observed, leading us to identify the expected true driver genes associated with the MSI-driven tumorigenic process. Several coding negatively selected MSI-related mutational events (n = 5) were shown to have deleterious effects on tumor cells. In the tumors in which deleterious MSI mutations were observed despite the negative selection, they were associated with worse survival in MSI CRC patients (hazard ratio, 3; 95% CI, 1.1-7.9; P = .03), suggesting their anticancer impact should be offset by other as yet unknown oncogenic processes that contribute to a poor prognosis.
    The present results identify the positive and negative driver somatic mutations acting in MSI-driven tumorigenesis, suggesting that genomic instability in MSI CRC plays a dual role in achieving tumor cell transformation. Exome sequencing data have been deposited in the European genome-phenome archive (accession: EGAS00001002477).
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  • 文章类型: Journal Article
    Familial Adenomatous Polyposis (FAP) is the second most common inherited predisposition to colorectal cancer (CRC) associated with the development of hundreds to thousands of adenomas in the colon and rectum. Mutations in APC are found in ~ 80% polyposis patients with FAP. In the remaining 20% no genetic diagnosis can be provided suggesting other genes or mechanisms that render APC inactive may be responsible. Copy number variants (CNVs) remain to be investigated in FAP and may account for disease in a proportion of polyposis patients. A cohort of 56 polyposis patients and 40 controls were screened for CNVs using the 2.7M microarray (Affymetrix) with data analysed using ChAS (Affymetrix). A total of 142 CNVs were identified unique to the polyposis cohort suggesting their involvement in CRC risk. We specifically identified CNVs in four unrelated polyposis patients among CRC susceptibility genes APC, DCC, MLH1 and CTNNB1 which are likely to have contributed to disease development in these patients. A recurrent deletion was observed at position 18p11.32 in 9% of the patients screened that was of particular interest. Further investigation is necessary to fully understand the role of these variants in CRC risk given the high prevalence among the patients screened.
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  • 文章类型: Journal Article
    DNA是抗癌治疗的主要靶标。DNA损伤引发一系列信号级联,促进细胞存活,包括DNA修复,细胞周期停滞,和自噬。在肿瘤细胞中观察到的DNA修复和自噬的基础和/或应激水平升高,与正常细胞相反,已被确定为影响抗癌治疗结果的最重要的药物反应程序。癌细胞中DNA修复与自噬之间的确切关系尚不清楚。一方面,自噬已被证明在DNA损伤后通过维持其合成之间的平衡来调节一些DNA修复蛋白,稳定,和退化。一只手,有证据表明,一些DNA修复分子在自噬的启动过程中起着至关重要的作用。在这次审查中,我们主要讨论DNA修复和自噬在抗癌治疗中的相互作用,并期望为癌症治疗提供一些有效的策略。
    DNA is the prime target of anticancer treatments. DNA damage triggers a series of signaling cascades promoting cellular survival, including DNA repair, cell cycle arrest, and autophagy. The elevated basal and/or stressful levels of both DNA repair and autophagy observed in tumor cells, in contrast to normal cells, have been identified as the most important drug-responsive programs that impact the outcome of anticancer therapy. The exact relationship between DNA repair and autophagy in cancer cells remains unclear. On one hand, autophagy has been shown to regulate some of the DNA repair proteins after DNA damage by maintaining the balance between their synthesis, stabilization, and degradation. One the other hand, some evidence has demonstrated that some DNA repair molecular have a crucial role in the initiation of autophagy. In this review, we mainly discuss the interplay between DNA repair and autophagy in anticancer therapy and expect to enlighten some effective strategies for cancer treatment.
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  • 文章类型: Journal Article
    Lynch syndrome (LS) is a tumor predisposing condition caused by constitutional defects in genes coding for components of the mismatch repair (MMR) apparatus. While hypermethylation of the promoter of the MMR gene MLH1 occurs in about 15% of colorectal cancer samples, it has also been observed as a constitutional alteration, in the absence of DNA sequence mutations, in a small number of LS patients. In order to obtain further insights on the phenotypic characteristics of MLH1 epimutation carriers, we investigated the somatic and constitutional MLH1 methylation status of 14 unrelated subjects with a suspicion of LS who were negative for MMR gene constitutional mutations and whose tumors did not express the MLH1 protein. A novel case of constitutional MLH1 epimutation was identified. This patient was affected with multiple primary tumors, including breast cancer, diagnosed starting from the age of 55 y. Investigation of her offspring by allele specific expression revealed that the epimutation was not stable across generations. We also found MLH1 hypermethylation in cancer samples from 4 additional patients who did not have evidence of constitutional defects. These patients had some characteristics of LS, namely early age at onset and/or positive family history, raising the possibility of genetic influences in the establishment of somatic MLH1 methylation.
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