MicroRNAs (miRNAs) are a class of short noncoding RNAs that participate in mastering the balance of gene-regulating networks. By targeting and controlling expression of messenger RNA, miRNAs can control highly complex signal transduction pathways and other biological pathways. Unique aberrant expression of miRNA at each stage of cancer development suggests that miRNA could play a novel role in cancer diagnosis and therapeutic strategies. Accumulated information on epigenetic modification of miRNA suggests a promising platform for miRNA in cancer therapy. Clinical applications exploiting the understanding of miRNA's function will be the next great challenge in cancer research.
"Furthermore, increasing evidence shows that miRNAs can act as oncogenes or tumor suppressors and may play important roles in tumorigenesis11,12,13. Therefore, miRNA expression profiles may become useful biomarkers for cancer diagnosis, prognosis and prediction of treatment-response and may serve as powerful tools for cancer prevention and therapy14,15,16,17,18,19. In recent years, some miRNAs have also been reported to be involved in drug-resistance in diseases such as breast cancer3, chronic lymphocytic leukemia20, metastatic colorectal cancer21 and esophageal cancer22. "
[Show abstract][Hide abstract] ABSTRACT: Aim:
To investigate the expression profile of microRNAs in inoperable advanced non-small cell lung cancer (NSCLC) patients receiving chemotherapy and the potential relevance of microRNAs to clinicopathological characteristics and prognosis.
Serum samples were taken from 260 inoperable advanced NSCLC patients and 260 healthy individuals. All the patients received cisplatin-based chemotherapy, including NP/NC regimens, GP/GC regimens, and TP/TC regimens. The serum levels of microRNAs (miR-125b, miR-10b, miR-34a and miR-155) were determined by quantitative real-time PCR.
Serum levels of the 4 microRNAs examined in NSCLC patients were significantly increased as compared with healthy individuals. The levels of miR-125b and miR-155 were changed in a similar pattern: the patients with stage IV disease had the highest one, while the patients with stage III A and stage III B disease showed similar increased levels. The levels of miR-10b and miR-34a in the patients with different stages were increased to similar extent. The level of miR-125b in poorly differentiated cancer was significantly higher than those in well and moderately differentiated cancers, while the levels of miR-10b, miR-34a, and miR-155 did not significantly differ with cancer differentiation. Among the 4 microRNAs examined, only miR-125b was significantly associated with therapeutic response, exhibiting higher expression levels in non-responsive patients. Furthermore, the high level of miR-125b was significantly correlated with poor patient survival. A multivariate Cox regression analysis showed that the expression level of miR-125b was an independent prognostic marker in NSCLC patients.
Our results suggest that miR-125b is a potential diagnostic or prognostic biomarker for NSCLC. This finding has important implications for development of targeted therapeutics to overcome chemotherapeutic resistance in NSCLC.
[Show abstract][Hide abstract] ABSTRACT: Circulating microRNAs (miRNAs) have emerged as novel noninvasive biomarkers for several diseases and other types of tissue injury. This study tested the hypothesis that changes in the levels of urinary miRNAs correlate with liver injury induced by hepatotoxicants. Sprague-Dawley rats were administered acetaminophen (APAP) or carbon tetrachloride (CCl(4)) and one nonhepatotoxicant (penicillin/PCN). Urine samples were collected over a 24 h period after a single oral dose of APAP (1250 mg/kg), CCl(4) (2000 mg/kg), or PCN (2400 mg/kg). APAP and CCl(4) induced liver injury based upon increased serum alanine and aspartate aminotransferase levels and histopathological findings, including liver necrosis. APAP and CCl(4) both significantly increased the urinary levels of 44 and 28 miRNAs, respectively. In addition, 10 of the increased miRNAs were in common between APAP and CCl(4). In contrast, PCN caused a slight decrease of a different nonoverlapping set of urinary miRNAs. Cluster analysis revealed a distinct urinary miRNA pattern from the hepatotoxicant-treated groups when compared with vehicle controls and PCN. Analysis of hepatic miRNA levels suggested that the liver was the source of the increased urinary miRNAs after APAP exposure; however, the results from CCl(4) were equivocal. Computational analysis was used to predict target genes of the 10 shared hepatotoxicant-induced miRNAs. Liver gene expression profiling using whole genome microarrays identified eight putative miRNA target genes that were significantly altered in the liver of APAP- and CCl(4)-treated animals. In conclusion, the patterns of urinary miRNA may hold promise as biomarkers of hepatotoxicant-induced liver injury.
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