Downregulation of microRNA‐100/microRNA‐125b is associated with lymph node metastasis in early colorectal cancer with submucosal invasion

A majority of early colorectal cancers (CRCs) with submucosal invasion undergo surgical operation, despite a very low incidence of lymph node metastasis. Our study aimed to identify microRNAs (miRNAs) specifically responsible for lymph node metastasis in submucosal CRCs. MicroRNA microarray analysis revealed that miR‐100 and miR‐125b expression levels were significantly lower in CRC tissues with lymph node metastases than in those without metastases. These results were validated by quantitative real‐time PCR in a larger set of clinical samples. The transfection of a miR‐100 or miR‐125b inhibitor into colon cancer HCT116 cells significantly increased cell invasion, migration, and MMP activity. Conversely, overexpression of miR‐100 or miR‐125b mimics significantly attenuated all these activities but did not affect cell growth. To identify target mRNAs, we undertook a gene expression array analysis of miR‐100‐silenced HCT116 cells as well as negative control cells. The Ingenuity Pathway Analysis, TargetScan software analyses, and subsequent verification of mRNA expression by real‐time PCR identified mammalian target of rapamycin (mTOR) and insulin‐like growth factor 1 receptor (IGF1R) as direct, and Fas and X‐linked inhibitor‐of‐apoptosis protein (XIAP) as indirect candidate targets for miR‐100 involved in lymph node metastasis. Knockdown of each gene by siRNA significantly reduced the invasiveness of HCT116 cells. These data clearly show that downregulation of miR‐100 and miR‐125b is closely associated with lymph node metastasis in submucosal CRC through enhancement of invasion, motility, and MMP activity. In particular, miR‐100 may promote metastasis by upregulating mTOR, IGF1R, Fas, and XIAP as targets. Thus, miR‐100 and miR‐125b may be novel biomarkers for lymph node metastasis of early CRCs with submucosal invasion.     

S100A4 participates in epithelial-mesenchymal transition in breast cancer via targeting MMP2

Numerous studies have shown that S100A4 acquires its metastasis-promoting effects via inducing epithelial-mesenchymal transition (EMT). However, its role and mechanism in EMT in breast cancer had not been clearly elucidated. Herein, we showed that the knockdown of S100A4 expression in breast cancer cell lines, MDA-MB-231 and MDA-MB-468, inhibited not only cell invasion ability greatly, but also the occurrence of EMT significantly. In addition, S100A4 knockdown could also decrease the expression of MMP2, a promoter and a mediator of the EMT processes in cancer. Above all, restoring the expression of MMP2 in MDA-MB-231 and MDA-MB-468 could not only rescue the invasion ability inhibited by knockdown of S100A4, but also reverse the EMT suppressed by knockdown of S100A4. In summary, our results indicated that S100A4 could promote the invasion ability of breast cancer cells via EMT, more importantly, it could participate in EMT via regulating MMP2 in breast cancer. Therefore, S100A4 could be a candidate biomarker for defining breast cancer metastasis and useful target for therapy.     

MicroRNA-29a promotes colorectal cancer metastasis by regulating matrix metalloproteinase 2 and E-cadherin via KLF4

Background:

Growing evidence suggests that miR-29a has an important role in regulating tumourigenesis and development of various types of cancer. However, the role and the underlying mechanism of miR-29a in colorectal cancer (CRC) remain largely unknown.

Methods:

MiR-29a targeted gene was identified by the luciferase assay and western blot. MiR-29a function was analysed by invasion assays and the orthotopic transplantation mouse model. The miR-29a pathway was assayed by real-time PCR, western blot and chip analysis.

Results:

KLF4 was identified as a direct target gene of miR-29a. MiR-29a promoted CRC cell invasion, which was blocked by re-expression of KLF4. In addition, MMP2 was identified as a novel direct target of KLF4. Both miR-29a overexpression and KLF4 knockdown promoted MMP2 expression but inhibited E-cadherin expression. Furthermore, clinical data indicated that both miR-29a high expression and KLF4 mRNA low expression were associated with metastasis and poor prognosis in CRC patients, and KLF4 protein expression was inversely correlated with MMP2 but positively correlated with E-cad protein expression.

Conclusion:

Increased expression of miR-29a promoted CRC metastasis by regulating MMP2/E-cad through direct targeting KLF4, which highlights the potential of the miR-29a inhibitor as a novel agent against CRC metastasis.     

外泌体中circ_0044366调控肿瘤相关成纤维细胞MMP2的表达促进结直肠癌转移的机制研究

背景与目的:结直肠癌(colorectal cancer,CRC)是全球癌症死亡的主要原因之一,大量研究发现,环状RNA(circular RNA,circRNA)作为miRNA分子海绵参与CRC细胞的增殖、迁移、侵袭和凋亡等病理生理学过程,circRNA/miRNA/靶基因/靶蛋白轴可能是CRC发生的重要原因之一.探...     

MMP13 is a potential prognostic marker for colorectal cancer

Matrix metalloproteinase 13 (MMP13), a member of the matrix metalloproteinase family, is considered to play a role in the tumor cell proliferation and invasion. The purpose of this study was to verify the expression of MMP13 in colorectal cancer (CRC) in vitro and in vivo, and subsequently analyze whether the MMP13 expression levels correlate with the clinicopathological features and prognosis of CRC patients. We assessed MMP13 mRNA expression profile in human colorectal adenocarcinoma cell lines by quantitative RT-PCR, and further verified if it was a secreted protein or not by Western blot analysis of cell culture medium. By immunohistochemical staining the immunoreactivity of MMP13 showed that MMP13 was localized in the cytoplasm of CRC cells. MMP13 mRNA expression of 80 cancerous tissues collected from UICC stage I to III CRC patients were examined by membrane array. The correlations between MMP13 mRNA expression and patients' clinicopathological features were analyzed. MMP13 was confirmed to be a secreted protein by Western blot analysis. The larger tumor size (P<0.0001), advanced clinical stage (P=0.002), tumor invasive depth (P=0.039), lymph node metastasis (P=0.001) and post-operative relapse (P<0.0001) were significantly correlated with the MMP13 mRNA overexpression. Patients with MMP13 mRNA overexpression have a higher risk of postoperative relapse (P<0.0001; OR=7.989; 95% CI, 2.607-24.481). The results of the present study highly suggest that MMP13 is a secreted protein with a significant correlation to development of postoperative relapse; hence it could be a potential prognostic marker for CRC patients.     

RasGRF2 promotes migration and invasion of colorectal cancer cells by modulating expression of MMP9 through Src/Akt/NF-κB pathway

Ras-specific guanine nucleotide-releasing factor 2 (RasGRF2) is a member of the guanine nucleotide exchange factors family which is expressed in a variety of tissues and cancer. However, the role of RasGRF2 in cancer is less reported, especially in colorectal cancer(CRC). Hence, the present study aimed to investigated the function of RasGRF2 and ways in which it affects tumor progression in CRC samples and cell lines. We first measured RasGRF2 mRNA level in 26 paired tumor and nontumor colon tissues after colon cancer surgical resection, and determined RasGRF2 protein level in 97 paired paraffin-embedded colon cancer tissues, and found that levels of RasGRF2 mRNA and protein were increased in colorectal tumor tissues, compared with adjacent non-tumor tissues. We then examined the effects of RasGRF2 knockdown on proliferation, migration and invasion were analyzed in CRC cells (SW480, HCT116 and LS174T). HCT116 cells with RasGRF2 knockdown were injected into the tail vein in nude mice to yield metastatic model, and tumor metastasis was measured as well. We found that knockdown of RasGRF2 in CRC cells reduced their migration and invasion in vitro and metastasis in mice. Furthermore, we explored the underlying molecular mechanism for RasGRF2-mediated CRC migration and invasion. The results showed that knockdown of RasGRF2 in CRC cells impairing the expression of MMP9 and inhibiting the activation of Src/Akt and NF-κB signaling. We conclude that RasGRF2 plays a role in controlling migration and invasion of CRC and modulates the expression of MMP9 through Src/PI 3-kinase and the NF-κB pathways.     

蛇葡萄素通过Dermcidin蛋白调节肝癌细胞株HepG2侵袭活力及侵袭基因表达的实验

 目的 研究蛇葡萄素（AMP）对肝癌细胞株HepG2侵袭活力及侵袭基因表达的调节作用及分子机制。方法 培养肝癌细胞株HepG2后用不同剂量的AMP处理（20、40、60、80 μmol/L）、转染Dermcidin的siRNA,测定细胞的迁移能力、侵袭能力以及Dermcidin、侵袭基因mRNA表达量。结果 不同剂量AMP处理后细胞的迁移、侵袭数目及细胞中Dermcidin、基质金属蛋白酶（MMP）2、MMP9、MMP10 mRNA水平均低于对照组,且AMP剂量越大,细胞的迁移、侵袭数目及细胞中Dermcidin、MMP2、MMP9、MMP10 mRNA水平越低;80 μmol/L AMP联合dermcidin siRNA后,HepG2细胞的迁移、侵袭数目以及细胞内MMP2、MMP9、MMP10 mRNA表达水平均增多。结论 AMP通过下调Dermcidin蛋白来抑制肝癌细胞株HepG2的侵袭活力、降低侵袭基因的表达水平。     

Curcumin inhibits tongue carcinoma cells migration and invasion through downregulation of matrix metallopeptidase 10

Squamous cell carcinoma (SCC) of tongue is an aggressive head and neck cancer with high propensity of regional spreading and invasion. Tongue carcinoma cells treated with curcumin, the major curcuminoid of the turmeric, demonstrated reduction in adhesion, migration, and invasion ability. High-throughput microarray analysis indicated that curcumin treatment suppressed matrix metallopeptidase 10 (MMP10) expression. MMP10 is overexpressed in tongue carcinoma tissues in comparison with the normal epithelia. Curcumin treatment on tongue carcinoma cell lines suppressed MMP10 expression at both mRNA and protein levels. Our results suggested that curcumin is a promising inhibitor to tongue cancer cells migration and invasion.     

Systemic shRNA mediated knock down of S100A4 in colorectal cancer xenografted mice reduces metastasis formation

The metastasis-inducing protein S100A4 was found to be a prognostic indicator for the development of metachronous metastases. S100A4 expression levels correlate with the formation of human colorectal cancer metastases and shorter patients’ survival. Inhibition of S100A4 expression in patients might therefore result in decreased metastasis formation and prolonged survival. In the present study, we used shRNA expression plasmids to inhibit S100A4 expression in the colorectal cancer cell lines HCT116, SW620 and DLD-1. Cell lines with reduced S100A4 expression showed reduced cell migration and invasion in vitro. The knock-down of S100A4 expression also led to significantly diminished formation of liver metastases when intrasplenically transplanted in mice (P = 0.004). We then focused on the therapeutic potential of systemically applied shRNA expression plasmids acting on S100A4 via repeated hydrodynamics-based tail vein injection of plasmid DNA. Mice, intrasplenically transplanted with HCT116 cells and treated systemically with S100A4-shRNA plasmids, showed a decrease of S100A4 and MMP9 expression levels, resulting in significantly reduced liver metastases (P = 0.005). In summary, we show for the first time the intratumoral knock-down of S100A4 via systemic application of S100A4-shRNA plasmid DNA, which restricts metastasis formation in a xenografted mouse model of colorectal cancer.     

Actinonin induces apoptosis in U937 leukemia cells

S100A4 has multiple functions in cell cycle progression and cell motility, and has been implicated in cancer invasion. In this study, we examined the expression of S100A4, E-cadherin and its related proteins in oral squamous cell carcinoma (SCC) cell lines with different invasive phenotypes, grade 4C and 4D. Furthermore, grade 4C OSC-19 cells expressing E-cadherin were transfected with S100A4-expression vector and the expression of E-cadherin-related proteins in the stable clone was examined to elucidate the relationship between S100A4 and E-cadherin. Constitutive over-expression of S100A4 in stable transformant of OSC-19 (OSC-19/S100A4) cells led to down-regulation of E-cadherin and β-catenin. Furthermore, grade 4D invasive cell lines (HOC313 and TSU) expressing S100A4 mRNA did not express E-cadherin, P-cadherin, and β-catenin, while γ-catenin protein was only weakly expressed. Thus, the mRNA expression of E-cadherin was reversely correlated with S100A4 expression in oral SCCs. Interestingly, vascular endothelial growth factor-C was up-regulated in OSC-19/S100A4 cells. In summary, S100A4-mediated regulation of E-cadherin expression may play an important mechanism in invasion and metastasis of oral SCC.     

靶向干扰前列腺源性ETS因子促进HT29细胞增殖与侵袭的机制

目的:研究干扰前列腺源性ETS因子促进HT29细胞增殖及侵袭的作用机制。方法:RT-PCR、Western blot技术测定空白对照组、空载体组和干扰载体组中前列腺源性ETS因子以及肿瘤增殖和侵袭相关基因Survivin、MMP7、MMP9的mRNA和蛋白表达情况。结果:RT-PCR、Western blot结果可见干扰载体组PDEF蛋白的表达较空载体组和对照组降低,同时干扰载体组能够上调Survivin、MMP7、MMP9的基因表达(P<0.05）。结论:干扰前列腺源性ETS因子可以通过上调HT29细胞的Survivin、MMP7、MMP9基因表达促进HT29细胞的存活、增殖以及侵袭转移。     

RNAi targeting urokinase‐type plasminogen activator receptor inhibits metastasis and progression of oral squamous cell carcinoma in vivo

It has been admitted that urokinase‐type plasminogen activator receptor (u‐PAR) is overexpressed in many human malignant tumors including oral squamous cell carcinoma (OSCC) and plays an important role in a variety of cancer key cellular events as a versatile signaling orchestrator. In our study, a retroviral vector expressing u‐PAR‐specific siRNA was injected into OSCC xenografts of nude mice to observe its inhibitory effects on OSCC. Our data demonstrate that siRNA targeting u‐PAR markedly suppressed tumor growth, reduced the expression of proliferation‐related gene, Ki‐67 and increased cell apoptosis, accompanying with the efficient and specific inhibition of endogenous u‐PAR expression in OSCC. More importantly, the mRNA and protein expression of MMP‐2, MMP‐9, VEGF‐C, VEGF‐D and VEGFR‐3 that are intimately involved in oral cancer invasion and metastasis, was simultaneously downregulated significantly as determined by quantitative real‐time RT‐PCR, Western blot and immunohistochemistry; and Gelatin and fibrin zymography showed that MMP‐9, MMP‐2 and u‐PA enzymatic activities were significantly reduced in u‐PAR‐specific siRNA group, compared to those in control groups. In addition, the expression of MDR‐1 gene related to drug resistance was obviously inhibited by silencing of u‐PAR. These findings suggest that RNAi targeting u‐PAR could effectively inhibit the metastasis and progression of OSCC in vivo. Thus, it may be used as a potent and specific therapy for oral cancer, especially in inhibiting and preventing cancer cell invasion and metastasis. © 2009 UICC     

Orthotopic implantation mouse model and cDNA microarray analysis indicates several genes potentially involved in lymph node metastasis of colorectal cancer

In colorectal cancer (CRC) patients, metastasis to the regional lymph node (LN) is an important first step in the dissemination of cancers. To identify the genes possibly involved in LN metastasis of CRC, we analyzed LN metastases in an orthotopic implantation mouse model with 22 CRC cell lines using Matrigel, an extracellular matrix protein derived from mice sarcoma, and combined the data with gene expression profiles of cDNA microarray of those cell lines. With this implantation analysis, the incidence of LN metastasis was 60% in 228 orthotopically implanted mice and varied from 100% to 0% among the cell lines. KM12c and Clone A showed LN metastasis in all orthotopically implanted mice, but DLD-1, HCT-8, and SW948 did not show LN metastases at all. In contrast, the incidence of liver and lung metastasis in 22 CRC cell lines was 13% and 1%, respectively. Combining those data with cDNA microarray in vitro , we isolated 636 genes that were differentially expressed depending on the incidence of LN metastasis. Among those genes, the expression level of ring finger protein 125 ( RNF125 ), previously known as an E3 ubiquitin ligase in T cell activation, was significantly different between primary tumors in Stage III CRC patients with LN metastasis and Stage II patients without LN metastasis. In conclusion, the orthotopic implantation mice model with Matrigel was useful, and we isolated candidate genes such as RNF125 that possibly play an important role in LN metastasis of CRC cells. ( Cancer Sci 2008; 99: 711–719)     

结直肠癌中 RhoGDI2的表达与肿瘤侵袭、转移及预后的关系

目的：探讨 RhoGDI2在结直肠癌中的表达与肿瘤侵袭、转移及预后的关系。方法：应用 Northern blot和 Western blot 检测具有不同侵袭、转移潜能的人结直肠癌细胞系（SW620、SW480）中 RhoGDI2 mRNA 及蛋白的表达。收集行手术切除并随访满5年的结直肠癌患者原发灶癌组织石蜡标本80例及相应的癌旁非癌组织、转移性淋巴结癌组织石蜡标本各20例。应用免疫组化法检测上述120例标本中 RhoGDI2蛋白的表达,分析其与临床病理特征及预后的关系。结果：SW620、SW480人结直肠癌细胞系中 RhoGDI2 mRNA 及蛋白的表达具有统计学差异（P <0.01）,前者表达均高于后者。结直肠癌相关组织中 RhoGDI2蛋白存在差异性表达（转移淋巴结癌组织>原发灶癌组织>癌旁非癌组织,P <0.01）。RhoGDI2蛋白在结直肠癌组织中的表达与肿瘤的浸润深度、淋巴结转移、远处转移、周围淋巴管浸润、周围神经浸润、TNM 分期显著相关（P <0.05）。RhoGDI2高表达的结直肠癌患者5年生存率显著低于低表达者（P <0.01）。高 RhoGDI2表达是结直肠癌的独立预后因素之一（P <0.05）。结论：RhoGDI2在结直肠癌中的高表达与肿瘤的侵袭、转移及预后不良密切相关,可能是一个有效的结直肠癌预后标志物。