Jiacong You

MiR-132 suppresses the migration and invasion of lung cancer cells via targeting the EMT regulator ZEB2.

MicroRNAs (miRNAs) are small, non-coding RNAs which can function as oncogenes or tumor suppressor genes in human cancers. Emerging evidence reveals that deregulation of miRNAs contributes to the human non-small cell lung cancer (NSCLC). In the present study, we demonstrated that the expression levels of miR-132 were dramatically decreased in examined NSCLC cell lines and clinical NSCLC tissue samples. Then, we found that introduction of miR-132 significantly suppressed the migration and invasion of lung cancer cells in vitro, suggesting that miR-132 may be a novel tumor suppressor. Further studies indicated that the EMT-related transcription factor ZEB2 was one direct target genes of miR-132, evidenced by the direct binding of miR-132 with the 3′ untranslated region (3′ UTR) of ZEB2. Further, miR-132 could decrease the expression of ZEB2 at the levels of mRNA and protein. Notably, the EMT marker E-cadherin or vimentin, a downstream of ZEB2, was also down-regulated or up-regulated upon miR-132 treatment. Additionally, over-expressing or silencing ZEB2 was able to elevate or inhibit the migration and invasion of lung cancer cells, parallel to the effect of miR-132 on the lung cancer cells. Meanwhile, knockdown of ZEB2 reversed the enhanced migration and invasion mediated by anti-miR-132. These results indicate that miR-132 suppresses the migration and invasion of NSCLC cells through targeting ZEB2 involving the EMT process. Thus, our finding provides new insight into the mechanism of NSCLC progression. Therapeutically, miR-132 may serve as a potential target in the treatment of human lung cancer.

MicroRNA-449a inhibits cell growth in lung cancer and regulates long noncoding RNA nuclear enriched abundant transcript 1

OBJECTIVE Lung cancer has become the primary cause of cancer-related death now. New therapies targeting the molecular regulatory machinery were required imperatively. MicroRNAs and long noncoding RNAs can respectively or cooperatively function as oncogenes or tumor suppressor genes in human cancers. The present study identified that miR-449a was down-regulated in tissue of human lung cancer. In this study, we aimed to investigate the function of miR-449a in NL9980 and L9981 lung carcinoma cells lines and the relationship with lncRNA nuclear enriched abundant transcript 1 (NEAT1). MATERIALS AND METHODS miR-449a was profiled in several lung carcinoma cell lines by quantitative reverse transcription-polymerase chain reaction RT-PCR. We analyzed the effects of miR-449a overexpression on proliferation, apoptosis and cell cycle in L9981 cells. The regulatory relationship between miR-449a and NEAT1 was predicted in silico and further studied by miR-449a inhibitor and mimics assay. RESULTS miR-449a was expressed in four cell lines, which we selected, however miR-449a was in high level in NL9980 and in low level in L9981 (P < 0.05). When the miR-449a was the overexpression in L9981 cells, the cell growth was suppressed, and the apoptosis cells were promoted compared with the control group (P < 0.05). The G1/G0 became longer and S, G2/M became shorter (P < 0.05) by miR-449a overexpression. Further study of the interaction between miR-449a and NEAT1 show that NEAT1 was up-regulated when cells were transfected with miR-449a inhibitor, and NEAT1 was down-regulated when cells transfected with miR-449a mimics. CONCLUSIONS Our data indicate that miR-449a may function as a suppressor of lung cancer, and affects the expression of NEAT1 in lung cancer cells.

Noncoding RNA small nucleolar RNA host gene 1 promote cell proliferation in nonsmall cell lung cancer

BACKGROUND Nonsmall cell lung cancer (NSCLC) is the major cause of cancer death worldwide. Increasing evidence shows that noncoding RNAs (ncRNAs) are widely involved in the development and progression of NSCLC. ncRNA small nucleolar RNA host gene 1 (SNHG1) has not been studied in cancer, especially its role in lung cancer remains unknown. Our studies were designed to investigate the expression and biological significance of SNHG1 in lung cancer. SNHG1 may be a novel ncRNA in early diagnosis in lung cancer. METHODS Noncoding RNA SNHG1 expression in 7 lung cancer cell lines was measured by quantitative real-time polymerase chain reaction. RNA interference approaches were used to find the biological functions of SNHG1. The effect of SNHG1 on proliferation was evaluated by cell count and crystal violet stains. RESULTS Noncoding RNA SNHG1 expression was significantly upregulated in lung cancer cells when compared with normal bronchial epithelial cells. In addition, in vitro assays our results indicated that knockdown of SNHG1 inhibited cell proliferation. CONCLUSIONS Our data indicated that ncRNA SNHG1 is significantly upregulated in NSCLC cell lines and may represent a new biomarker and a potential therapeutic target for NSCLC intervention.

Erratum: The lncRNA XIST exhibits oncogenic properties via regulation of miR-449a and Bcl-2 in human non-small cell lung cancer

Long non-coding RNAs (lncRNAs) are associated with the occurrence, development and prognoses of non-small cell lung cancer (NSCLC). In the present study, we investigated the functional mechanisms of the lncRNA XIST in two human NSCLC cell lines, A549 and NCI-H1299. In all the 5 NSCLC cell lines (NL9980, NCI-H1299, NCI-H460, SPC-A-1 and A549) tested, the expression levels of XIST were significantly elevated, as compared with those in normal human bronchial epithelial cell line BEAS-2B. In A549 and NCI-H1299 cells, knockdown of XIST by siRNA significantly inhibited the cell proliferation, migration and invasion, and promoted cell apoptosis. Furthermore, XIST knockdown elevated the expression of E-cadherin, and suppressed the expression of Bcl-2. Moreover, knockdown of XIST significantly suppressed the tumor growth in NSCLC A549 xenograft mouse model. Bioinformatic analysis and luciferase reporter assays revealed that XIST was negatively regulated by miR-449a. We further identified reciprocal repression between XIST and miR449a, which eventually influenced the expression of Bcl-2: XIST functioned as a miRNA sponge of miR-449a, which was a negative regulator of Bcl-2. These data show that expression of the lncRNA XIST is associated with an increased growth rate and metastatic potential in NSCLC A549 and NCI-H1299 cells partially through miR-449a, and suggest that XIST may be a potential prognostic factor and therapeutic target for patients with NSCLC.

Nm23-H1 was involved in regulation of KAI1 expression in high-metastatic lung cancer cells L9981

BACKGROUND The tetraspanin KAI1/CD82 was identified as a tumor metastasis suppressor that down-regulated in malignant progression of lung cancer. However, the underlying mechanism of anti-metastasis role of KAI1 in lung cancer is hardly known. In this paper, we sought to study the function and regulatory mechanism of KAI1 in high metastasis lung cancer cell line. METHODS KAI1 expression was detected in high/low metastatic large lung cancer cell line L9981/NL9980 by quantitative real-time polymerase chain reaction (qRT-PCR). The tumor suppressor function of KAI1 was determined by wound healing assay after over-expression or knockdown of KAI1 in L9981 or NL9980 cells. Invasion assay was performed to detect the invasion ability of L9981 by transfection of KAI1. The effect of tumor suppressor p53 on KAI1 expression was measured by western blot and luciferase assay. Then the regulation of KAI1 due to over-expression of metastasis suppressor nm23-H1 was monitored by qRT-PCR, western blot and reporter gene assay. The progression of L9981 cells after p53 and nm23-H1 expression was detected by invasion assay. Also, methylation status of KAI1 promoter in NL9980 and L9981 cells were examined by bisulfite sequencing and methylation-specific PCR. RESULTS We found that KAI1 is down-regulated in high metastatic L9981 cells compare with NL9980 cells. The migration and invasion of L9981 cells were remarkably suppressed in vitro by KAI1 transfection. The migration ability of NL9980 was enhanced by inhibition of KAI1. Furthermore, KAI1 expression was induced after over-expression of p53 or nm23-H1, while cell invasion was inhibited in L9981 cells. The results of reporter analysis indicated that KAI1 promoter region between -922 to -846 could response to nm23-H1. In addition, we discovered only slight methylation of KAI1 promoter, which showed that loss expression of KAI1 in L9981 cells may not due to promoter methylation. CONCLUSIONS The results suggested that nm23-H1 was involved in the KAI1-regulated inhibition of metastasis in lung cancer cells. More insights into the relationship between KAI1 and other metastasis suppressors will pave the way for the elucidation of anti-metastasis mechanism in lung cancer.

Advances in the relationship between tumor cell metabolism and tumor metastasis

Intracellular nutrients and the rate of energy flowing in tumor cells are often higher than that in normal cells due to the prolonged stress of tumor-specific microenvironment. In this context, the metabolism of tumor cells provides the fuel of bio-synthesis and energy required for tumor metastasis. Consistent with this, the abnormal metabolism such as extremely active glucose metabolism and excessive accumulating of fatty acid is also discovered in metastatic tumors. Previous Studies have confirmed that the regulation of tumor metabolism can affect the tumor metastasis, and some of these have been successfully applied in clinical effective, positive way. Thus, targeting metabolism of tumor cells might be an effectively positive way to prevent the metastasis of tumor. So, our review is focused on the research development of the relationship between tumor metabolism and metastasis as well as the underlying mechanism.

[Mutational analysis of hOGG1 gene promoter in patients with non-small cell lung cancer].

BACKGROUND AND OBJECTIVE 8-hydroxygumine DNA glycosylase 1 (OGG1) is a DNA repair enzyme, which can repair damaged DNA by excising 8-dihydro-8-oxoguanine (8-OH-G). Polymorphisms in human OGG1 gene (hOGG1) may alter glycosylase activity, thereby affects its repair to the damaged DNA, resulting in contribution to carcinogenesis. However, an association of genetic variants of hOGG1 promoter with non-small cell lung cancer (NSCLC) remains unclear. The present study aims to explore whether there are mutations in the promoter region of hOGG1 and the association of the potential genetic variants with NSCLC. METHODS Forty lung cancer patients were enrolled from January, 2003 to December, 2005 in the first affiliated hospital of Soochow University. PCR-SSCP followed by direct sequencing were performed to detect mutations within the promoter region of the hOGG1 gene in NSCLC and corresponding paracancerous lung tissues. RESULTS No abnormal mutation was found in the promoter region of the hOGG1 gene in 40 patients with NSCLC. However, a SNP rs159153 in hOGG1 was significantly associated with higher TNM stage (P=0.008). Moreover, lower frequency of lymph node metastasis was observed in smoker patients with NSCLC (P=0.034). CONCLUSIONS The SNP rs159153 in the promoter region of the hOGG1 gene and smoking history may effectively forebode the aggressiveness and metastatic potential of NSCLC.

Screening of Metastasis-related MicroRNAs in the Large-cell Lung Cancer Cell Lines with Different Metastastic Potentials

背景与目的 微小RNA（microRNAs, miRNAs）参与调节肿瘤发生发展的多个过程，包括细胞的分裂增殖、细胞周期、凋亡、血管形成、侵袭和转移等。本研究应用miRNA芯片检测具有高低不同转移潜能人大细胞肺癌细胞株L9981和NL9980的miRNA表达谱，从中筛选出与大细胞肺癌转移相关的miRNAs。 方法 收集L9981和NL9980细胞，抽提总RNA进行CY3标记，将标记RNA在miRNA芯片上进行杂交反应。通过数据统计分析，筛选出表达明显差异的miRNAs。应用Real-time PCR验证芯片结果，并应用生物信息学方法预测靶基因。 结果 在不同转移潜能人大细胞肺癌L9981和NL9980细胞株中共筛选到22个表达明显差异的miRNAs。与NL9980相比，在L9981中有13个miRNAs表达上调，9个表达下调。Real-time PCR验证miR-125a-3p在细胞中的表达水平与芯片结果趋势一致，预测其靶基因可能为胰岛素样生长因子2。 结论 筛选得到与大细胞肺癌转移相关的miRNA表达谱。

[Enrichment and function research of large cell lung cancer stem cell-like cells].

BACKGROUND AND OBJECTIVE There are no universal method to recognize and screen for lung cancer stem cell markers and indicators. Commonly used methods are flow Cytometry and learning from other cancer stem cell sorting tags to sort lung cancer stem cells. But this method has low specificity screening, the workload is huge. In this study, Serum-free suspension culture was used to enrich lung cancer stem cells, and explore method for lung cancer stem cell screening. METHODS Human large lung cancer cell line-L9981 was cultured in serum-free and growth factors added medium, and spheres were obtained. Then the morphological differences of sphere cells and adherent L9981 cells cultured in serum-containing mediums are observed. Cell proliferation was analyzed by Vi-cell viability analyzer; invasion ability was tested by transwell assay; and in vivo tumorigenicity of the two groups of cells was studied in nude mouse. RESULTS Compared with adherent L9981 cells cultured in serum-containing mediums, cells cultured in serum-free medium display sphere appearance. Doubling time of adherent cells and sphere cells are (56.05±1.95) h and (33.00±1.44) h respectively; Spheroid cells had higher invasion and tumorigenicity ability, 5 times and 20 times respectively, than adherent cells. CONCLUSION Suspension cultured L9981 in Serum-free medium could form spheroid populations. Cells in spheres had higher ability of invasion and Tumorigenicity than adherent L9981 cells. These results indicated spheroid L9981 cells contained enriched lung cancer stem cells, and Serum-free suspension culture can be a candidate method for enriching lung cancer stem cell.

Advances of Hypoxia and Lung Cancer

Lung cancer is one of the malignant tumors with fastest growing rates in incidence and mortality in our country, also with largest threat to human health and life. However, the exact mechanisms underlying lung cancer development remain unclear. The microenvironment of tumor hypoxia was discovered in 1955, but hypoxia in lung cancer tissues had not been successfully detected till 2006. Further studies show that hypoxia not only functions through the resistance to radiotherapy, but also regulates lung cancer development, invasion, metastasis, chemotherapy resistance and prognosis through an important oncogene HIF (hypoxia inducible factor), with its regulators PHD (prolyl hydroxylase domain) and pVHL (product of von Hippel-Lindau gene). Therefore, hypoxia, HIF, PHD and pVHL should be considered as potential therapeutic targets for lung cancer pathogenesis and progression.