Colorectal cancer (CRC) is the third most common malignancy and the second most common cause of cancer death worldwide. Early detection of CRC can improve patient survival rates; thus, the identification of noninvasive diagnostic markers is urgently needed. MicroRNAs (miRNAs) have extensive potential to diagnose several diseases, including cancer. In this study, we compared the expression pattern of miRNAs from plasma and stool samples of patients with early stages of CRC (I, II) with that of healthy subjects. We performed miRNA profiling using microarrays on plasma and stool samples of eight patients with CRC and four healthy subjects. Seven miRNAs were found to be underexpressed in both plasma and stool samples of patients with CRC versus healthy subjects. Then, we aimed to verify two out of these seven differentially expressed miRNAs (let-7a-5p and let-7f-5p) by quantitative reverse transcriptase polymerase chain reaction on a larger set of plasma and stool samples of 51 patients with CRC and 26 healthy subjects. We confirmed the results of microarray analysis since their expression was significantly lower in stool and plasma samples of patients with CRC. Moreover, receiver operating characteristic curve analysis demonstrated that fecal let-7f expression levels have significant sensitivity and specificity to distinguish between patients with CRC and healthy subjects. In conclusion, if the results are confirmed in larger series of patients, underexpressed let-7a-5p and let-7f-5p miRNAs in both plasma and stool samples of patients with CRC may serve potentially as noninvasive molecular biomarkers for the early detection of CRC.

Recent studies underline the involvement of microRNAs in cancer development through induction of immune suppression milieu and evolution of drug resistance. The goal of this study was to evaluate the effects of miR-146a on regulatory T cells' frequencies, T-lymphocyte proliferation, and cytokine expression as well as drug resistance in cancer cells. We found that miR-146a was overexpressed in colon cancer HT-29 cells. Peripheral blood mononuclear cells were obtained from healthy donors and were co-cultured with transfected HT-29 cells. Afterward, peripheral blood mononuclear cell proliferation, expression of anti-inflammatory cytokines, and regulatory T cells' frequencies were assayed. Also, drug resistance in transfected HT-29 cells was analyzed following treatment with 5-fluorouracil and irinotecan. Overexpression of miR-146a increased transforming growth factor-β and interleukin-10 expressions and enhanced regulatory T cells' frequencies in peripheral blood mononuclear cells. Also, the number of cells undergoing cell cycle arrest and apoptosis significantly decreased in transfected HT-29 cancer cells. In conclusion, upregulation of miR-146a plays an important role in enhancing immune suppression through increasing the regulatory T cells' population. Also, our data indicated that colon cancer drug resistance is possibly associated with miR-146a overexpression.

Background:Chronic Hepatitis B (CHB) is accompanied by inflammation of liver because of infection with Hepatitis B Virus (HBV). Previous studies revealed an inverse association between vitamin D and HBV DNA levels.Objectives:The current study aimed to investigate the levels of 25 (OH) D3 (the steady form of vitamin D), miR-378 and HBV DNA in the patients with CHB.Patients and Methods:One hundred and seventy three patients with HBeAg negative CHB were recruited for the study. Plasma levels of HBVDNA and 25 (OH) D3 were quantified. The expression level of miR-378 in plasma was measured by a relative quantitative Real Time Polymerase Chain Reaction (qRT-PCR) assay.Results:In the pathway regression analysis, the plasma level of 25 (OH) D3 showed a significant inverse correlation with plasma levels of HBV DNA (-0.198, P = 0.008) and direct correlation with miR-378 (0.188, P = 0.013). Similarly plasma level of miR-378 had inverse association with HBV DNA level (-0.177, P = 0.020).Conclusions:These results suggest that vitamin D could involve in a miRNA- mediated regulatory pathway in control of HBV replication. Further studies are recommended to understand the effects of miR-378 and anti-infective action of vitamin D on Hepatitis B Virus.

Background:Recent evidence has suggested that epithelial cancers including colorectal cancer (CRC) have driven by a small population of self-renewing, multi-potent cells termed cancer stem cells (CSCs) which could be responsible for recurrence of cancer. Aldehyde dehydrogenase 1 (ALDH1) activity has used as a functional stem cell biomarker to isolate CSCs in different cancers such as colorectal cancer.Objectives:The main aim of this research was to determine the utility of ALDH1 activity along with CD44 and EPCAM in identifying stem cell-like cells in human HT-29 colonic adenocarcinoma cell line.Materials and Methods:In this experimental study, colon CSCs biomarkers including CD44, EPCAM and ALDH1 in colonospheres and parent cells have analyzed by flow cytometry. The expression levels of stemness genes in spheroid and parental cells have investigated using SYBR Green real-time PCR. In addition, in vivo xenografts assay has performed to determine tumorigenic potential of tumor spheroid cells in nude mice.Results:According to results, over 92% of spheroids were CD44+/EpCAM+, while parent cells only have expressed 38% of CD44/EpCAM biomarkers (P < 0.001). Controversially, ALDH activity was about 2-fold higher in the parent cells than spheroid cells (P < 0.05). In comparison with the parental cells, expression levels of ‘‘stemness’’ genes, like Sox2, Oct4, Nanog, C-myc, and Klf4 have significantly increased in colonosphere cells (P < 0.05). Further, administration of 2500 spheroids could be sufficient to initiate tumor growth in nude mice, while 1x106 of parental cells has needed to form tumor.Conclusions:For the first time, we have shown that colonospheres with low ALDH1 activity has indicated increased tumorigenic potential and stemness properties. So, it hasn’t seemed that ALDH1 could become a useful biomarker to identify CSCs population in HT-29 cell line.