MicroRNA-302a Functions as a Putative Tumor Suppressor in Colon Cancer by Targeting Akt

Micro RNAs (miRNAs) are important regulators involved in various physical and pathological processes, including cancer. The miRNA-302 family has been documented as playing a critical role in carcinogenesis. In this study, we investigated the role of miRNA-302a in colon cancer. MiRNA-302a expression was detected in 44 colon cancer tissues and 10 normal colon tissues, and their clinicopathological significance was analyzed. Cell proliferation and cell cycle analysis were performed on colon cancer cells that stably expressed miRNA-302a. The target gene of miRNA-302a and the downstream pathway were further investigated. Compared with normal colon tissues, miRNA-302a expression was downregulated in colon cancer tissues. Overexpression of miRNA-302a induced G1/S cell cycle arrest in colon cancer cells, and suppressed colon cancer cell proliferation both in vitro and in vivo. Furthermore, miRNA-302a inhibited AKT expression by directly binding to its 3′ untranslated region, resulting in subsequent alterations of the AKT-GSK3β-cyclin D1 pathway. These results reveal miRNA-302a as a tumor suppressor in colon cancer, suggesting that miRNA-302a may be used as a potential target for therapeutic intervention in colon cancer.     

GAIP-interacting protein,C-terminus is involved in the induction of zinc-finger protein 143 in response to insulin-like growth factor-1 in colon cancer cells

Previously, we reported that the expression of zinc-finger protein 143 (ZNF143) was induced by insulin-like growth factor-1 (IGF-1) via reactive oxygen species (ROS)- and phosphatidylinositide-3-kinase (PI3-kinase)-linked pathways in colon cancer cells. Here, we investigated whether GAIP-interacting protein, C-terminus (GIPC), a binding partner of IGF-1R, is involved in ZNF143 expression through IGF-1 and IGF-1R signaling in colon cancer cells. The knockdown of GIPC in colon cancer cells reduced ZNF143 expression in response to IGF-1. IGF-1 signaling through its receptor, leading to the phosphorylation and activation of the PI3-kinase-Akt pathway and mitogenactivated protein kinases (MAPKs) was unaffected by the knockdown of GIPC, indicating the independence of the GIPC-linked pathway from PI3-kinase- and MAPK-linked signaling in IGF-1-induced ZNF143 expression. In accordance with previous results in breast cancer cells (Choi et al., 2010), the knockdown of GIPC reduced ROS production in response to IGF-1 in colon cancer cells. Furthermore, the knockdown of GIPC reduced the expression of Rad51, which is regulated by ZNF143, in response to IGF-1 in colon cancer cells. Taken together, these data suggest that GIPC is involved in IGF-1 signaling leading to ZNF143 expression through the regulation of ROS production, which may play a role for colon cancer tumorigenesis.     

The Induction of microRNA-16 in Colon Cancer Cells by Protein Arginine Deiminase Inhibition Causes a p53-Dependent Cell Cycle Arrest

Protein Arginine Deiminases (PADs) catalyze the post-translational conversion of peptidyl-Arginine to peptidyl-Citrulline in a calcium-dependent, irreversible reaction. Evidence is emerging that PADs play a role in carcinogenesis. To determine the cancer-associated functional implications of PADs, we designed a small molecule PAD inhibitor (called Chor-amidine or Cl-amidine), and tested the impact of this drug on the cell cycle. Data derived from experiments in colon cancer cells indicate that Cl-amidine causes a G1 arrest, and that this was p53-dependent. In a separate set of experiments, we found that Cl-amidine caused a significant increase in microRNA-16 (miRNA-16), and that this increase was also p53-dependent. Because miRNA-16 is a putative tumor suppressor miRNA, and others have found that miRNA-16 suppresses proliferation, we hypothesized that the p53-dependent G1 arrest associated with PAD inhibition was, in turn, dependent on miRNA-16 expression. Results are consistent with this hypothesis. As well, we found the G1 arrest is at least in part due to the ability of Cl-amidine-mediated expression of miRNA-16 to suppress its'' G1-associated targets: cyclins D1, D2, D3, E1, and cdk6. Our study sheds light into the mechanisms by which PAD inhibition can protect against or treat colon cancer.     

MicroRNA-451 regulates AMPK/mTORC1 signaling and fascin1 expression in HT-29 colorectal cancer

The earlier studies have shown that Fascin1 (FSCN1), the actin bundling protein, is over-expressed in colorectal cancers, and is associated with cancer cell progression. Here, we aimed to understand the molecular mechanisms regulating FSCN1 expression by focusing on mammalian target of rapamycin (mTOR) signaling and its regulator microRNA-451. We found that microRNA-451 was over-expressed in multiple colorectal cancer tissues, and its expression was correlated with mTOR complex 1 (mTORC1) activity and FSCN1 expression. In cultured colorectal cancer HT-29 cells, knockdown of FSCN1 by RNAi inhibited cell migration and proliferation. Activation of mTORC1 was required for FSCN1 expression, HT-29 cell migration and proliferation, as RAD001 and rapamycin, two mTORC1 inhibitors, suppressed FSCN1 expression, HT-29 cell migration and proliferation. Meanwhile, forced activation of AMP-activated protein kinase (AMPK), the negative regulator of mTORC1, by its activators or by the genetic mutation, inhibited mTORC1 activation, FSCN1 expression, cell migration and proliferation. In HT-29 cells, we found that over-expression of microRNA-451 inhibited AMPK activation, causing mTORC1 over-activation and FSCN1 up-regulation, cells were with high migration ability and proliferation rate. Significantly, these effects by microRNA-451 were largely inhibited by mTORC1 inhibitors or the AMPK activator AICAR. On the other hand, knockdown of miRNA-451 by the treatment of HT-29 cells with miRNA-451 antagomir inhibited mTORC1 activation and FSCN1 expression. The proliferation and migration of HT-29 cells after miRNA-45 knockdown were also inhibited. Our results suggested that the over-expressed microRNA-451 in colon cancer cells might inhibit AMPK to activate mTORC1, which mediates FSCN1 expression and cancer cell progression.     

Aberrant Expression of Some Circulating miRNAs in Childhood Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a heterogeneous cancer commonly affecting children due to dysregulation of miRNA expression. In the current study, authors investigated the expression profile for miRNA-125b-1 and miRNA-203 among childhood ALL. Blood samples were collected from newly diagnosed childhood ALL and healthy control children. The expression profile for candidate miRNAs was detected using quantitative RT-PCR analysis. Statistical analysis were performed using receiver operating characteristic curve (ROC) to examine the diagnostic efficacy of the two miRNA and their levels among ALL clinicopathological factors and phenotypes. The median expression level for miRNA-125b-1 was significantly high in childhood ALL; while miRNA-203 level was significantly low in childhood ALL as compared to control ones. MiRNA-125-1 reported significant increase in T-ALL as compared to other ALL phenotypes. Median miRNA-203 level was high in T-ALL followed by pre-B-ALL although no significant difference was reported. Clinicopathological factors did not emphasize significance with either detected miRNAs. Using ROC curve the diagnostic efficacy was significant with an area under the curve 0.858 for miRNA-125b-1 (83.72, 100%) and 0.878 for miRNA-203 (97.67, 86.96%). The combination of the two key miRNAs revealed absolute sensitivity (100%). MiRNA-125b-1 and miRNA-203 can be useful molecular markers for diagnosis of ALL. Further studies with large cohort are warranted to validate these results.     

MiRNA-21 Expression Decreases from Primary Tumors to Liver Metastases in Colorectal Carcinoma

Objective

Metastasis is the major cause of death in colorectal cancer patients. Expression of certain miRNAs in the primary tumors has been shown to be associated with progression of colorectal cancer and the initiation of metastasis. In this study, we compared miRNA expression in primary colorectal cancer and corresponding liver metastases in order to get an idea of the oncogenic importance of the miRNAs in established metastases.

Methods

We analyzed the expression of miRNA-21, miRNA-31 and miRNA-373 in corresponding formalin-fixed paraffin-embedded (FFPE) tissue samples of primary colorectal cancer, liver metastasis and healthy tissues of 29 patients by quantitative real-time PCR.

Results

All three miRNAs were significantly up-regulated in the primary tumor tissues as compared to healthy colon mucosa of the respective patients (p < 0.01). MiRNA-21 and miRNA-31 were also higher expressed in liver metastases as compared to healthy liver tissues (p < 0.01). No significant difference of expression of miRNA-31 and miRNA-373 was observed between primary tumors and metastases. Of note, miRNA-21 expression was significantly reduced in liver metastases as compared to the primary colorectal tumors (p < 0.01).

Conclusion

In the context of previous studies demonstrating increased miRNA-21 expression in metastatic primary tumors, our findings raise the question whether miRNA-21 might be involved in the initiation but not in the perpetuation and growth of metastases.     

MicroRNA-143 and -145 in colon cancer

MicroRNAs (miRNAs) are endogenous, small non-coding RNAs (20-22 nucleotides) that negatively regulate gene expression at the translational level by base pairing to the 3' untranslated region of target messenger RNAs. More than 400 miRNAs have been identified in humans and are evolutionally conserved from plants to animals. It has been revealed that miRNAs regulate various biological processes, such as development, cell differentiation, cell proliferation, and cell death. It is predicted that 30% of protein-encoding genes are regulated by miRNAs. Inappropriate expression of miRNAs has been found in cancer. Especially, the expression level of miRNAs that act like anti-oncogenes is frequently reduced in cancers because of chromosome aberrations. In addition, since the processing of miRNAs has been characterized to be enzymatic in nature, the expression levels of miRNAs are closely associated with the activity and levels of such enzymes. In this review, we discuss recent remarkable advances in miRNA biogenesis, bio-networking involving miRNAs, and their roles in carcinogenesis. Further, we discuss the expression of miRNA-143 and -145 in colon cancer and their roles in carcinogenesis. The available data suggest that miRNAs would be potentially useful as diagnostic and therapeutic tools.     

miRNA-191对前列腺癌的增殖、迁移侵袭能力的影响及其机制

目的:观察miRNA-191对前列腺癌的增殖、迁移和侵袭能力的影响,并探讨其机制。方法:分别检测4种人前列癌细胞系(PC-3、DU-145、LNCa P、22RU1)及人正常前列腺细胞RWPE-2中miRNA-191的表达水平,并选择前列腺癌细胞系PC-3作为实验对象。将PC-3细胞分为3组:空白对照组(不转染)、miRNA-191 NC组(Inhibitor NC转染PC-3细胞)、miRNA-191 Inhibitor组(miRNA-191 Inhibitor转染PC-3细胞),每组设置3个复孔。采用RTq PCR法检测PC-3细胞miRNA-191和PLCD1的mRNA表达水平;采用CCK8法检测PC-3细胞增殖水平;采用划痕实验和侵袭实验分别检测PC-3细胞迁移能力和侵袭能力;通过Targetscan靶基因预测网站,筛选PLCD1作为miRNA-191的靶向蛋白,并用双荧光素酶靶标实验验证;采用Western blot法检测PC-3细胞PLCD1的蛋白表达。结果:与RWPE-2细胞相比,人前列癌细胞中mi NRA-191的表达水平显著升高(P<0.05),且miRNA-1...     

MicroRNA-143 Targets Syndecan-1 to Repress Cell Growth in Melanoma

Melanoma is the most aggressive type of skin cancer with a rapid progression and a limited efficiency of therapeutics. Recently, studies have identified some microRNAs playing important roles in the development of melanoma. Syndecan-1 (Syn-1), dysregulated in many cancers, plays important roles in tumor progression by controlling cell proliferation. In this study, we investigated whether microRNA-143 (miR-143) is involved in the regulation of Syn-1 and thus plays a functional role in melanoma. We found that miR-143 expression was significantly lower in melanoma tissues than in normal tissues and its low expression was closely related to clinical stages of melanoma. Further experiments showed that consistent with the inhibitory effects induced by knockdown of Syn-1, overexpression of miR-143 suppressed cell proliferation, promoted G1 phase arrest and induced apoptosis in melanoma. Downregulation of miR-143 apparently produced opposite effects. Combined treatment of miR-143 overexpression and Syn-1 knockdown induced remarkable synergistic effects, while reconstitution of miR-143-resistant Syn-1 reversed the inhibitory activity of miR-143. Moreover, miR-143 level was inversely correlated with Syn-1 expression in melanoma cells. miR-143 directly targeted the 3′-untranslated regions of Syn-1 mRNA and they were in the same Argonaute2 complex. Taken together, this study revealed a link between miRNA-143 and Syn-1 in the pathogenesis of melanoma. MiR-143 plays an important role in the regulation of cell growth in melanoma. Restoration of miR-143 expression may represent a promising and efficient therapeutic approach for targeting malignant melanoma.     

Retroviral insertions in Evi12, a novel common virus integration site upstream of Tra1/Grp94, frequently coincide with insertions in the gene encoding the peripheral cannabinoid receptor Cnr2

The common virus integration site (VIS) Evi11 was recently identified within the gene encoding the hematopoietic G-protein-coupled peripheral cannabinoid receptor Cnr2 (also referred to as Cb2). Here we show that Cnr2 is a frequent target (12%) for insertion of Cas-Br-M murine leukemia virus (MuLV) in primary tumors in NIH/Swiss mice. Multiple provirus insertions in Evi11 were cloned and shown to be located within the 3' untranslated region of the candidate proto-oncogene Cnr2. These results suggest that proviral insertion in the Cnr2 gene is an important step in Cas-Br-M MuLV-induced leukemogenesis in NIH/Swiss mice. To isolate Evi11/Cnr2 collaborating proto-oncogenes, we searched for novel common VISs in the Cas-Br-M MuLV-induced primary tumors and identified a novel frequent common VIS, Evi12 (14%). Interestingly, 54% of the Evi11/Cnr2-rearranged primary tumors contained insertions in Evi12 as well, which suggests cooperative action of the target genes in these two common VISs in leukemogenesis. By interspecific backcross analysis it was shown that Evi12 resides on mouse chromosome 10 in a region that shares homology with human chromosomes 12q and 19p. Sequence analysis demonstrated that Evi12 is located upstream of the gene encoding the molecular chaperone Tra1/Grp94, which was previously mapped to mouse chromosome 10 and human chromosome 12q22-24. Thus, Tra1/Grp94 is a candidate target gene for retroviral activation or inactivation in Evi12. However, Northern and Western blot analyses did not provide evidence that proviral insertion had altered the expression of Tra1/Grp94. Additional studies are required to determine whether Tra1/Grp94 or another candidate proto-oncogene in Evi12 is involved in leukemogenesis.     

Anti-PD1 therapy induces lymphocyte-derived exosomal miRNA-4315 release inhibiting Bim-mediated apoptosis of tumor cells

Anti-PD1 immunotherapy, as a single agent or in combination with standard chemotherapies, has significantly improved the outcome of many patients with cancers. However, resistance to anti-PD1 antibodies often decreases the long-term therapeutic benefits. Despite this observation in clinical practice, the molecular mechanisms associated with resistance to anti-PD1 antibody therapy have not yet been elucidated. To identify the mechanisms of resistance associated with anti-PD1 antibody therapy, we developed cellular models including purified T cells and different cancer cell lines from glioblastoma, lung adenocarcinoma, breast cancer and ovarian carcinoma. A murine model of lung cancer was also used. Longitudinal blood samples of patients treated with anti-PD1 therapy were also used to perform a proof-of-concept study of our findings. We found that anti-PD1 exposure of T-cell promotes an enrichment of exosomal miRNA-4315. We also noted that exosomal miRNA-4315 induced a phenomenon of apopto-resistance to conventional chemotherapies in cancer cells receiving exosomal miRNA-4315. At molecular level, we discern that the apopto-resistance phenomenon was associated with the miRNA-4315-mediated downregulation of Bim, a proapoptotic protein. In cellular and mice models, we observed that the BH3 mimetic agent ABT263 circumvented this resistance. A longitudinal study using patient blood showed that miRNA-4315 and cytochrome c can be used to define the time period during which the addition of ABT263 therapy may effectively increase cancer cell death and bypass anti-PD1 resistance.This work provides a blood biomarker (exosomal miRNA-4315) for patient stratification developing a phenomenon of resistance to anti-PD1 antibody therapy and also identifies a therapeutic alternative (the use of a BH3 mimetic drug) to limit this resistance phenomenon.Subject terms: Cancer, miRNAs     

Clinical significance of blood-based miRNAs as diagnostic and prognostic nucleic acid markers in breast cancer: Comparative to conventional tumor markers

microRNAs (miRNAs) are implicated in carcinogenesis and their expression in biological fluids offer great potential as nucleic acid markers for cancer detection and progression. Authors investigated the expression level of miRNAs (miRNA-21, miRNA-126, and miRNA-155) to evaluate their role as diagnostic and prognostic markers for breast cancer compared with other commonly used protein-based markers (CEA and CA15-3). Serum samples from patients with breast cancer (n = 96), patients with benign breast lesion (n = 47), and healthy individuals (n = 39) were enrolled for detection of miRNA expression levels and protein-based tumor markers using fluorescent real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Correlation among investigated markers with clinicopathological factors and clinical outcomes were determined. Expression of miRNA-21 and miRNA-155 revealed significant increases in patients with breast cancer compared with both benign and control groups, the same result was reported for tumor markers; on the other hand, miRNA-126 was significantly decreased in breast cancer group as compared with the other two groups. miRNA frequencies were significantly related to clinical staging and histological grading as compared with tumor markers. Patients with breast cancer with increased miRNA-21 and miRNA-155 and decreased miRNA-126 expressions had significantly worse disease-free survival, while only miRNA-21 and miRNA-126 showed poor OS (P< 0.005). In conclusion, investigated miRNAs were superior over tumor markers for the early stage of breast cancer especially those with high-risk factor and their assessment in blood facilitates their role as a potential prognostic molecular marker.     

Cell-Free MicroRNA Expression Profiles in Malignant Effusion Associated with Patient Survival in Non-Small Cell Lung Cancer

Objective

MicroRNAs (miRNAs) expression is altered in cancer cells, and miRNAs could serve as diagnostic and prognostic biomarker for cancer patients. This study was designed to analyze circulating miRNAs expression in the malignant pleural effusion (MPE) and their association with patient survival in non-small cell lung cancer (NSCLC).

Methods

Pleural effusion from 184 patients with NSCLC and MPE were collected. MiRNA microarray and bioinformatics interpretation were used to evaluate miRNA expression profiles in 10 NSCLC patients with different survival prognosis. Associations were validated in 184 patients (randomly classified into training and validation set with equal number in each group) using quantitative RT-PCR. Risk scores were formulated based on the expression signature of miRNAs. Clinical data, such as patient survival, were collected for correlation analysis.

Results

Thirty-three miRNAs were found to be altered more than two-fold by microarray in malignant effusions between longer-survival and shorter-survival groups, and levels of five miRNAs (miRNA-93, miRNA-100, miRNA-134, miRNA-151 and miRNA-345) were significantly associated with overall survival. High expression of miR-100 and low expression of miRNA-93, miRNA-134, miRNA-151 and miRNA-345 were associated with poor survival in both the training and validation cohort. Patients with high risk scores had overall poor survival compared to the patients with low risk scores. Risk score was an independent predictor of patient survival.

Conclusions

Expression patterns of miRNAs are systematically altered in MPE of patient with NSCLC. The five miRNA signature from the effusion may serve as a predictor for the overall survival of patients with lung cancers.