Exosomal microRNA in serum is a novel biomarker of recurrence in human colorectal cancer

Bioinformatic Interrogation of 5p-arm and 3p-arm Specific miRNA Expression Using TCGA Datasets

MicroRNAs (miRNAs) play important roles in cellular functions and developmental processes. They are also implicated in oncogenesis mechanisms and could serve as potential cancer biomarkers. Using high-throughput miRNA sequencing information, expression of both the 5p-arm and 3p-arm mature miRNAs were demonstrated and generated from the single miRNA hairpin precursor. However, current miRNA annotations lack comprehensive 5p-arm/3p-arm feature annotations. Among known human mature miRNAs, only half of them are annotated with arm features. This generated ambiguous results in many miRNA-Sequencing (miRNA-Seq) studies. In this report, we have interrogated the TCGA (the Cancer Genome Atlas) miRNA expression datasets with an improved, fully annotated human 5p-arm and 3p-arm miRNA reference list. By utilizing this comprehensive miRNA arm-feature annotations, enhanced determinations and clear annotations were achieved for the miRNA isoforms (isomiRs) recognized from the sequencing reads. In the gastric cancer (STAD) dataset, as an example, 32 5p-arm/3p-arm OPEN ACCESS J. Clin. Med. 2015, 4 1799 specific miRNAs were found to be down-regulated and 24 5p-arm/3p-arm specific miRNAs were found to be up-regulated. We have further extended miRNA biomarker discoveries to additional TCGA miRNA-Seq datasets and provided extensive expression information on 5p-arm/3p-arm miRNAs across multiple cancer types. Our results identified several miRNAs that could be potential common biomarkers for human cancers.

Identification of Recurrence-Related microRNAs from Bone Marrow in Hepatocellular Carcinoma Patients

Hepatocellular carcinoma (HCC) is a poor-prognosis cancer due to its high rate of recurrence. microRNAs (miRNAs) are a class of small non-coding RNA molecules that affect crucial processes in cancer development. The objective of this study is to identify the role of miRNAs in patient bone marrow (BM) and explore the function of these molecules during HCC progression. We purified miRNAs from bone marrow cells of seven HCC patients, and divided them into three fractions by cell surface markers as follows: CD14(+) (macrophage), CD14(-)/CD45(+) (lymphocyte), and CD14(-)/CD45(-)/EpCAM(+) (epithelial cell). We employed microarray-based profiling to analyze miRNA expression in the bone marrow of patients with HCC. Differentially expressed miRNAs were significantly different between fractions from whole bone marrow, macrophages, and lymphocytes, and depended on stages in tumor progression. Differences in expression of miRNAs associated with cell proliferation also varied significantly between HCC patients with recurrence, multiple tumors, and advanced clinical stages. These results suggest that miRNA profiles in separated fractions of BM cells are associated with HCC progression.

Exosomes in cancer: small particle, big player

Exosomes have emerged as a novel mode of intercellular communication. Exosomes can shuttle bioactive molecules including proteins, DNA, mRNA, as well as non-coding RNAs from one cell to another, leading to the exchange of genetic information and reprogramming of the recipient cells. Increasing evidence suggests that tumor cells release excessive amount of exosomes, which may influence tumor initiation, growth, progression, metastasis, and drug resistance. In addition, exosomes transfer message from tumor cells to immune cells and stromal cells, contributing to the escape from immune surveillance and the formation of tumor niche. In this review, we highlight the recent advances in the biology of exosomes as cancer communicasomes. We review the multifaceted roles of exosomes, the small secreted particles, in communicating with other cells within tumor microenvironment. Given that exosomes are cell type specific, stable, and accessible from body fluids, exosomes may provide promising biomarkers for cancer diagnosis and represent new targets for cancer therapy.