Identification of the molecular function of tripartite motif containing 58 in human lung cancer

Lung cancer is a major public health problem worldwide, with a high associated incidence and mortality. In the present study, novel epigenetic signatures were identified through genome-wide DNA methylation microarrays. The results revealed that tripartite motif containing 58 (TRIM58), a potential tumor suppressor gene exhibited high methylation and low expression in lung cancer tissue samples compared with normal tissues. Receiver operating characteristic curve analysis demonstrated that TRIM58 may be a promising early diagnostic indicator of lung cancer. In addition, the present study analyzed the role of TRIM58 in tumorigenesis and development in lung cancer A549 cells. Wound healing assay and transwell migration assay were used to investigate cell migration, and flow cytometry analysis was used to detect apoptosis. Silencing TRIM58 accelerated the proliferation and migration of lung cancer cells. In contrast, the overexpression of TRIM58 significantly inhibited the proliferation and migration of lung cancer cells and promoted apoptosis. Gene set enrichment analysis revealed that TRIM58 expression was negatively correlated with MYC targets, G₂M checkpoints and the mTORC1 signaling pathway. These results of the present study suggested that TRIM58, a potential tumor suppressor gene may serve as a novel diagnostic biomarker and therapeutic target in human lung cancer.     

热休克蛋白27在乳腺癌发生发展中的作用

乳腺癌已经成为继肺癌之后威胁人类生命的第二大癌症。热休克蛋白27(heat shock protein 27, HSP27)是真核生物细胞内普遍存在的一种小分子热休克蛋白, 作为一种ATP非依赖性分子伴侣, 当细胞受到各种生理和环境上的刺激出现非致命性的细胞损伤时发挥保护细胞的功能。近年来的研究发现乳腺癌细胞中存在着HSP27的持续高水平表达, 且被认为与乳腺癌的发生、发展、预后以及化疗耐药的发生有密切的关系。肿瘤的发生、增殖、侵袭和转移是一个极其复杂的多步骤动态过程, 深入研究HSP27在乳腺癌发生、发展中的作用机制, 将有望为乳腺癌的防治提供新思路。      

Role of DNA-dependent protein kinase catalytic subunit in cancer development and treatment

DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a key component of the non-homologous end-joining (NHEJ) pathway, is involved in DNA double-strand break repair, immunocompetence, genomic integrity, and epidermal growth factor receptor signaling. Clinical studies indicate that expression and activity of DNA-PKcs is correlated with cancer progression and response to treatment. Various anti-DNA-PKcs strategies have been developed and tested in preclinical studies to exploit the benefit of DNA-PKcs inhibition in sensitization of radiotherapy and in combined modality therapy with other antitumor agents. In this article, we review the association between DNA-PKcs and cancer development and discuss current approaches and mechanisms for inhibition of DNA-PKcs. The future challenges are to understand how DNA-PKcs activity is correlated with cancer susceptibility and to identify those patients who would most benefit from DNA-PKcs inhibition.     

Role of viruses in the development of breast cancer

The most common cancer worldwide among women is breast cancer. The initiation, promotion, and progression of this cancer result from both internal and external factors. The International Agency for Research on Cancer stated that 18-20% of cancers are linked to infection, and the list of definite, probable, and possible carcinogenic agents is growing each year. Among them, biological carcinogens play a significant role. In this review, data covering infection-associated breast and lung cancers are discussed and presented as possible involvements as pathogens in cancer. Because carcinogenesis is a multistep process with several contributing factors, we evaluated to what extent infection is significant, and concluded that members of the herpesvirus, polyomavirus, papillomavirus, and retrovirus families definitely associate with breast cancer. Detailed studies of viral mechanisms support this conclusion, but have presented problems with experimental settings. It is apparent that more effort needs to be devoted to assessing the role of these viruses in carcinogenesis, by characterizing additional confounding and synergistic effects of carcinogenic factors. We propose that preventing and treating infections may possibly stop or even eliminate certain types of cancers.     

Role of CHK2 in cancer development

DNA repair pathways enable tumour cells to survive DNA damage induced by external agents such as therapeutic treatments. Signalling cascades involved in these pathways comprise the DNA-dependent protein kinase (DNA-PK), Ataxia-telangiectasia mutated (ATM), ATM and Rad3 related (ATR) and checkpoint kinases I and 2 (Chk1/Chk2), among others. ATM and ATR phosphorylate, respectively, Chk2 and Chk1, leading to activation of checkpoints. Chk2 acts as a signal distributor, dispersing checkpoint signal to downstream targets such as p53, Cdc25A, Cdc25C, BRCA1 and E2F1. A role of Chk2 as a candidate tumour suppressor has been suggested based on both mouse genetics and somatic tumour studies. We will discuss here the possible role of this kinase in human carcinogenesis and the possibility to use it as a target to increment DNA damage in cancer cells in response to DNA-damaging therapies.     

MICA蛋白在肿瘤生物治疗中的作用

近年,NK细胞的活化性受体NKG2D已成为研究热点,作为NKG2D配体的MICA(人类MHC-Ⅰ类分子链相关基因A)蛋白越来越受关注.机体内MICA以膜型和分泌型两种形式存在.膜型MICA与NKG2D相互作用在肿瘤免疫监视中起着非常重要的作用;与此相反,分泌型MICA不仅下调NKG2D受体的表达,而且下调其细胞毒活性,对免疫细胞抗肿瘤起阻碍作用,可能是肿瘤免疫逃逸的一种新的机制.因此,可以利用这些特点发挥MICA蛋白在肿瘤生物治疗中的应用价值.     

热休克蛋白27在胃癌中的表达

目的:探讨热休克蛋白27(heat shock protein 27,HSP27)在胃癌、癌旁正常胃黏膜组织和慢性胃炎中的蛋白及其mRNA的表达情况,为HSP27应用于临床胃良恶性病变的鉴别诊断提供实验依据.方法:采用组织芯片技术检测病理诊断明确的34例胃癌患者的胃癌组织标本及相对应的距胃癌组织边缘1.5 cm处的组织、距胃癌组织边缘5 cm以上的正常组织以及胃炎组织中HSP27的表达,RT-PCR法对8例患者的胃癌组织及其对应的正常胃黏膜组织、胃溃疡组织和慢性胃炎组织的HSP27 mRNA表达情况进行检测.比较组织芯片中胃癌与癌旁以及胃癌与正常胃黏膜组织之间HSP27蛋白的表达差异,并比较HSP27 mRNA的表达情况.结果:HSP27蛋白主要表达于细胞质中,少量表达于细胞核及细胞膜;HSP27蛋白在胃癌、癌旁、正常胃黏膜组织及胃炎中的表达阳性率分别为52.94%、11.78%、14.71%和5.88%,过表达率分别为38.24%、11.77%、11.77%和5.88%.HSP 27蛋白在胃癌中的表达量明显高于胃癌旁组织、胃炎组织及正常胃黏膜组织(P<0.01).在mRNA水平,胃癌组织的HSP27表达也明显高于其余3组(P<0.01).结论:胃癌中HSP 27的表达水平明显高于胃癌旁组织,胃炎组织和正常胃黏膜组织,HSP27有可能成为一种潜在性的用于鉴别良恶性胃黏膜病变的标志物.     

Bioinformatics analysis of immune infiltrates and tripartite motif (TRIM) family genes in hepatocellular carcinoma

BackgroundThe tripartite motif (TRIM) family are important members of the Gene-finger-containing E3 ubiquitin-conjugating enzyme and are involved in the progression of hepatocellular carcinoma (HCC). Previous studies have largely focused on gene expression and molecular pathways, while the underlying role of the TRIM family in the tumor immune microenvironment (TIME) remains poorly understood.MethodsWe systematically explored the correlations of prominent TRIM genes with immune checkpoints and immune infiltrates in 231 HCC samples [International Cancer Genome Consortium (ICGC) cohort (n=231); The Cancer Genome Atlas (TCGA) cohort (n=370)]. A prognostic risk model was constructed using the least absolute shrinkage and selection operator (LASSO) algorithm and multivariate Cox regression analysis in the ICGC cohort. Kaplan-Meier curves based on the overall survival (OS) were used to assess differences in survival between clusters. We utilized gene set variation analysis (GSVA) to characterize the differences in biological functions. Based on univariate and multivariate Cox progression analysis, we developed a risk score signature and verified its reliability and validity. The Tumor Immune Single-cell Hub (TISCH) single-cell database was employed to evaluate the correlation of TRIM genes with the tumor microenvironment.ResultsCluster 1 was preferentially associated with a favorable prognosis (P<0.001). The amino acid, fatty acid, and drug metabolism pathways were significantly enriched in cluster 2. A prognosis risk score project was established and evaluated based on the 9 independent prognostic genes (all P<0.05). The immune score and stromal scores of patients with low-risk scores were greater than those of patients with high-risk scores (all P<0.001). However, patients with a high-risk score exhibited lower responses to immune check-point inhibitors (ICIs), sorafenib, and transarterial chemoembolization (TACE) treatment (all P<0.05). Consistently, TRIM genes showed the same influence in the external TCGA cohort. TRIM gene-based signatures were implicated in TIME and their copy-number alterations dynamically impacted the abundance of tumor-infiltrating immune cells.ConclusionsOur findings revealed that MID1, TRIM5, TRIM22, TRIM28, TRIM 31, TRIM37, TRIM38, TRIM47, and TRIM74 could serve as efficient prognostic biomarkers and therapeutic targets in HCC. The identified TRIM gene-based signatures could serve as important TIME mediators in HCC, potentially increasing immune treatment efficacy.     

Role of LKB1 in lung cancer development

Three phenotypically related genetic syndromes and their lesions (LKB1, PTEN, and TSC1/2) are identified as frequently altered in lung cancer. LKB1, a kinase inactivated in 30% of lung cancers, is discussed in this review. Loss of LKB1 regulation often coincident with KRAS activation allows for unchecked growth and the metabolic capacity to accommodate the proliferation.     

RNA结合蛋白HuR在肿瘤中的作用

RNA结合蛋白(RNA-binding proteins,RBPs)是近年来发现的具有多种生物学作用的分子家族,其中,HuR属于胚胎致死异常视觉家族的RBPs,表达广泛。最初发现HuR与神经分化相关,通过与靶mRNA3’UTR的ARE结合,在转录后水平调控RNA的稳定性和蛋白表达。近年发现,HuR与细胞增殖、肿瘤相关的炎症和血管生成密切相关,提示HuR可能参与了肿瘤发生、发展和转移过程。因此,以HuR为靶点的抗肿瘤策略可能为将来的肿瘤治疗带来希望。     

Heat-shock protein 27 plays the key role in gemcitabine-resistance of pancreatic cancer cells

Pancreatic cancer is one of the most fatal types of cancer in developed countries. Most patients have locally advanced or metastatic cancerous lesions when they are diagnosed, due to the progressive, invasive and metastatic capacity of this disease to liver, lymph nodes and distant organs during early stages. Although the only curative therapy is complete surgical resection, the disease has usually already progressed by the time of diagnosis, and the majority of patients have metastatic disease. Therefore, palliative chemotherapy remains the only therapy for patients with progressive disease. Gemcitabine has been used for pancreatic cancer as the most effective anticancer drug. However, there are many cases resistant to gemcitabine. Thus, a better understanding of the molecular mechanisms of resistance to gemcitabine is essential to allow it to be used more effectively. Our previous proteomic studies demonstrated that the expression of heat-shock protein 27 (HSP27) was increased in gemcitabine-resistant pancreatic cancer cells and this might play a role in determining the sensitivity of pancreatic cancer to gemcitabine. Increased HSP27 expression in tumor specimens was related to resistance to gemcitabine and a shorter survival period in patients with pancreatic cancer. Furthermore, it has been shown that treatment strategies combining the HSP inhibitor KNK437 or interferon-γ (IFN-γ) with gemcitabine, were effective in gemcitabine-resistant pancreatic cancer cells in vitro. Furthermore, combined therapy of gemcitabine with IFN-γ of gemcitabine-resistant pancreatic cancer-bearing nude mice showed synergistic therapeutic effects on gemcitabine-resistant pancreatic cancer bearers. In this review, we summarize the current understanding of HSP27 and its role in gemcitabine resistance.     

Role of IL-17A in the development of colitis-associated cancer

A close relationship between inflammation and colon cancer has been widely accepted, and interleukin (IL)-17A plays an important role in controlling colonic inflammation. However, the role of IL-17A has not yet been validated in colitis-associated cancer (CAC). This study aims to identify the effects of IL-17A in tumorigenesis utilizing IL-17A-deficient mice in an experimental CAC model. CAC was induced in both the IL-17A-deficient and the C57BL/6 (wild-type, WT) mice by injection of 12.5 mg/kg azoxymethane followed by three rounds of 1.7% dextran sodium sulfate exposure to elicit colitis. On day 63 after the start of the study, mice were sacrificed. Colonic inflammation, proliferation and tumorigenesis were evaluated. Tumor numbers per mouse (1.43 versus 5.80; P = 0.02) and mean tumor size (1.17 versus 3.58 mm; P = 0.01) were significantly decreased in IL-17A-deficient mice compared with WT mice. Furthermore, the inflammation and the proliferation scores of IL-17A-deficient mice were significantly lower than WT mice. In the analysis of inflammatory mediators, IL-6, interferon-γ, tumor necrosis factor-α and IL-17A were markedly decreased in IL-17A-deficient mice compared with WT mice. In the western blot analysis, p-STAT3, cyclin D1, cyclin-dependent kinase 2, cyclin E, Glycogen synthase kinase 3-β and p-Akt were downregulated in IL-17A-deficient mice. Immunohistochemical staining with p-STAT3, Ki-67 and β-catenin revealed lower number of stained cells in IL-17A-deficient mice compared with WT mice. IL-17A ablation significantly decreases CAC tumorigenesis and thus may play an important role associated with chronic colitis.     

P27蛋白与调控因子cyclinE在结肠肿瘤组织中的表达

背景与目的:细胞调控与肿瘤发生、发展的关系是肿瘤研究的一个热点,肿瘤细胞调控因子也是肿瘤的重要预后因子。P27蛋白和cyclinE是细胞周期负性调控因子,到目前为止它们在肿瘤中所起的作用尚未十分清楚。本研究拟探讨P27蛋白与cyclinE在结肠肿瘤组织中的表达特征,以及与肿瘤特异性生长因子(tumorspecialgrowthfactor,TSGF)的关系。方法:正常结肠组织23例,结肠息肉28例(炎性息肉13例,腺瘤性息肉15例),结肠癌18例。上述病例常规病理检查确诊。用免疫组化方法检测所有标本中P27蛋白与cyclinE的表达以及与TSGF的关系。结果:P27蛋白和cyclinE在正常结肠组织、炎性息肉和腺瘤性结肠息肉组织中呈阳性表达,主要位于腺细胞的胞浆和细胞外基质。在结肠癌组织仅有少量表达,并且仅在少数腺样细胞的胞浆内。TSGF在结肠癌组织中的含量(117.30±57.02)明显高于正常组织(64.16±27.50)(P<0.01),但与炎性息肉组织(92.50±47.90)相比,差异无显著性(P>0.05)。结论:P27蛋白和cyclinE参与肿瘤的调控过程,P27蛋白和cyclinE表达下降提示结肠癌的可能。     

Vincristine regulates the phosphorylation of the antiapoptotic protein HSP27 in breast cancer cells

Vincristine is an antitumor drug that inhibits microtubule polymerization, causes G2/M arrest and induces apoptosis. 2D-PAGE and MALDI-TOF-MS analysis of vincristine effects on MCF7 cells, revealed a vincristine upregulated form and a vincristine downregulated form of the antiapoptotic protein HSP27. These findings linked to the lack of vincristine effect over HSP27 mRNA, suggest a protein post-translational modification. Further assays indicated the presence of a phosphorylated peptide, containing serine 82, only in the vincristine upregulated form. Serine 82 phosphorylation was confirmed using specific antibodies. Thus, phosphorylation of HSP27 may play a role in the cellular response to vincristine.     

肿瘤相关成纤维细胞在肺癌发生发展及耐药中的作用

肿瘤相关成纤维细胞（cancer associated fibroblasts，CAFs）是肿瘤微环境（the tumor microenvironment, TME）中重要组成部分。大量研究发现，CAFs通过分泌表达各种因子、调节信号通路来形成一个更有利于肺癌增殖、侵袭转移的微环境，而且与肺癌的耐药、预后密切相关。该文将就CAFs在肺癌发展演变进程中的具体作用机制做一综述，以期为肺癌治疗寻找新的药物作用靶点，为改善肺癌患者的预后提供新的方向。     

Role of mitogen-activated protein kinase kinase 4 in cancer

Mitogen-activated protein (MAP) kinase kinase 4 (MKK4) is a component of stress activated MAP kinase signaling modules. It directly phosphorylates and activates the c-Jun N-terminal kinase (JNK) and p38 families of MAP kinases in response to environmental stress, pro-inflammatory cytokines and developmental cues. MKK4 is ubiquitously expressed and the targeted deletion of the Mkk4 gene in mice results in early embryonic lethality. Further studies in mice have indicated a role for MKK4 in liver formation, the immune system and cardiac hypertrophy. In humans, it is reported that loss of function mutations in the MKK4 gene are found in approximately 5% of tumors from a variety of tissues, suggesting it may have a tumor suppression function. Furthermore, MKK4 has been identified as a suppressor of metastasis of prostate and ovarian cancers. However, the role of MKK4 in cancer development appears complex as other studies support a pro-oncogenic role for MKK4 and JNK. Here we review the biochemical and functional properties of MKK4 and discuss the likely mechanisms by which it may regulate the steps leading to the formation of cancers.