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BACKGROUND microRNAs (miRNAs) are involved in the regulation of various cellular processes, such as differentiation, proliferation, metabolism, and apoptosis, and they have been implicated in several diseases, including cancers. METHODS To assess the role of miRNA in the progression of breast cancer, we performed TaqMan-based miRNA profiling for plasma from patients with breast cancer (n = 53), unrelated diseases (n = 40), or matched healthy controls (n = 40), and for breast tumors or adjacent non-tumors (n = 41). RESULTS We selected 18 miRNAs with predicted roles in breast cancer and demonstrated that let-7i (p = 0.019), let-7a (p = 0.02), and miR-650 (p = 0.008) were significantly up-regulated in plasma; miR-21 (p < 0.001) is up-regulated in breast cancer tissue, and miR-30e was down-regulated in both plasma (p < 0.001) and breast cancer tissues (p = 0.004). Plasma miR-30e expression was shown to be statistically associated with age (p = 0.0402) and clinical stage (p = 0.007). However, receiver-operating characteristic curve analyses suggested that miR-30e expression cannot significantly differentiate breast cancer from healthy tissue or plasma. Consistent with a potential role for miR-30e in breast cancer, three predicted targets of miR-30e (RAB11A, BNIP3L, and RAB32) are up-regulated in breast cancer tissue. CONCLUSIONS These findings suggest that reduced miR-30e correlates with the clinical stage of breast cancer. It is worthwhile to further explore that the potential role of miR-30e as a tumor suppressor in breast cancer, as well as its potential therapeutic utility.

Background E2F-1 is a transcription factor that stimulates cellular proliferation and cell cycle progression. E2F-1 alone is sufficient to stimulate cells to initiate DNA synthesis, and this unscheduled entry into S phase is a potent trigger of apoptosis. Gemcitabine, a novel pyrimidine analogue with structural and metabolic similarities to cytarabine, also can efficiently induce apoptosis, especially for cancer cells that are already in S phase. Gemcitabine has established antitumor activity against solid tumors, including head and neck, ovarian, and non-small cell lung cancers. Therefore, we hypothesized that exogenous E2F-1 expression could accumulate cells in the S phase and thus sensitize them to gemcitabine. Methods We constructed an adenoviral vector (AdCMVE2F-1) to transduce the exogenous E2F-1 gene into human cancer cells. Infection of human colon cancer cells with AdCMVE2F-1 resulted in the overexpression of E2F-1 mRNA and protein in a dose-dependent manner and consequently induced accumulation in S phase as measured by FACS analysis. To assess the synergistic antitumor effect of AdCMVE2F-1 and gemcitabine, the human colon cancer cel lines SW620, DLD-1, and LoVo were infected with AdCMVE2F-1 at various multiplicities of infection and then exposed to various concentrations of gemcitabine 24 hours after infection. Result Isobologram analysis showed that E2F-1-transduced cancer cells exhibited higher sensitivity to gemcitabine treatment compared to control virus-infected cells. Treatment with AdCMVE2F-1 plus gemcitabine enhanced endogenous p53 expression in LoVo cells, which contain wild-type p53; however, the finding that the synergistic effect can also be observed in mutant p53-expressing SW620 and DLD-1 cells suggests that wild-type p53 function may not be necessary for the therapeutic effects of this drug combination. Conclusions: Our data demonstrate that overexpression of ectopic E2F-1 protein may render cels more sensitive to gemcitabine-mediated apoptosis, an outcome that has important general implications for the treatment of human cancer.

BACKGROUND MicroRNAs (miRNAs) exist stably and reproducibly in plasma and may be used as biomarkers for various diseases. Little is known about circulating miRNAs in the peripheral blood of juvenile patients with asthma. METHODS In this study, we used hybridization arrays to compare the miRNA expression profiles among 6 juvenile patients with or without asthma. Using quantitative PCR (qPCR), we verified the expression levels of these miRNAs in plasma from patients with asthma (n = 40) and healthy subjects (n = 14). RESULTS Our results showed that the levels of plasma miR-Let7C, miR-486, and miR-1260a in childhood asthma patients were significantly higher than in healthy controls (p < 0.01). Additionally, miR-1260a is correlated with the treatment schedule of these patients and patients with long treatment times had higher expression of miR-1260a than short treatment times; miR494 was significantly associated with challenge, and miR-3162-3p was significantly associated with MEF25 in asthma patients suggesting a potential correlation of miRNA levels with clinical disease parameters. Receiver operator characteristic analysis confirmed that the levels of miR-3162-3p could be used to discriminate childhood asthma patients from healthy subjects (area under the curve of 0.821), suggesting it may be a potential diagnostic biomarker. CONCLUSIONS These results indicate that circulating miR-3162-3p and miR-1260a should be further evaluated as potential non-invasive biomarkers in diagnosis and treatment for childhood asthma.