MiR-146a promotes the asymmetric division and inhibits the self-renewal ability of breast cancer stem-like cells via indirect upregulation of Let-7

MiR-146a could stimulate tumor growth or block tumor proliferation in systemic malignancies, referring to the specific downstream targeted gene. However, its roles in breast cancer stem-like cells (BrCSCs) are barely known. To dig out its mechanistic functions, we explored the indicative roles of miR-146 in preclinical study, regardless of the hormone receptor status, and the positive correlation between miR-146 and better prognosis was proved, as its correlation to Let-7c was. To uncover the implicated mechanisms, we first identified the suppressive role of miR-146a in stem cells’ renewal, which was achieved by promoting the asymmetric division of BrCSCs. Let-7c was previously revealed with its suppressive functions in stem-like cells expansion, and miR-146 was predicated and successfully proved to bind to and degrade the 3’UTR of LIN28, a maturation blocker of Let-7 family. Results further showed that miR-146a increased the Let-7c level through degrading LIN28, and LIN28 inhibition is required for miR-146a induction of asymmetric stem cells’ division. Moreover, Let-7 controlled Wnt signaling pathway activity could be strengthened due to the miR146 inhibition of H19, later of which was often activated in stem cells group with functional existence of Wnt signaling. H19 itself in turn formed the positive feedback regulation with Let-7. Our results suggested the miR-146a/LIN28/Wnt signaling circle in restraining the symmetric cells division, which was specifically referred to the controlling of the small circle of Let-7c and H19, and together, this dual axis could help to prohibit the stem cells expansion.     

The clinical significance of circulating miR-21, miR-142, miR-143, and miR-146a in patients with prostate cancer

BackgroundProstate cancer (PCa) is the most common type of solid tissue cancer among men in western countries. In this study, we determined the levels of circulating miR-21, miR-142, miR-143, miR-146a, and RNU 44 levels as controls for early diagnosis of PCa.MethodsThe circulating miRNA levels in peripheral blood samples from 43 localized PCa patients, 12 metastatic PCa (MET) patients, and a control group of, 42 benign prostate hyperplasia (BPH) patients with a total of 97 volunteers were determined the by PCR method.ResultsNo differences in the DCT values were found among the groups. In PCa and PCaMet groups the expression of miR21 and miR142 were higher compared to the BHP group. No other differences were observed among the other groups. miR21 expression in the PCa group was 6.29 folds upregulated whereas in the PCaMet group 10.84 folds up-regulated. When the total expression of miR142 is evaluated, it showed a positive correlation with mir21 and mir 146 (both p<0.001). Also, the expression of miR146 shows a positive correlation with both miR21 and miR143 (both p<0.001). Expression of miRNAs was found to be an independent diagnostic factor in patients with Gleason score, PSA, and free PSA levels.ConclusionsOur study showed that co-expression of miR21, miR-142, miR-143, and miR-146a and the upregulation of miR-21 resulted in increased prostate carcinoma cell growth. In the PCaMet group, miR21 is the most upregulated of all miRNAs. These markers may provide a novel diagnostic tool to help diagnose PCa with aggressive behavior.     

Inhibition of the autophagic flux by salinomycin in breast cancer stem-like/progenitor cells interferes with their maintenance

Breast cancer tissue contains a small population of cells that have the ability to self-renew; these cells are known as cancer stem-like cells (CSCs). We have recently shown that autophagy is essential for the tumorigenicity of these CSCs. Salinomycin (Sal), a K⁺/H⁺ ionophore, has recently been shown to be at least 100 times more effective than paclitaxel in reducing the proportion of breast CSCs. However, its mechanisms of action are still unclear. We show here that Sal blocked both autophagy flux and lysosomal proteolytic activity in both CSCs and non-CSCs derived from breast cancer cells. GFP-LC3 staining combined with fluorescent dextran uptake and LysoTracker-Red staining showed that autophagosome/lysosome fusion was not altered by Sal treatment. Acridine orange staining provided evidence that lysosomes display the characteristics of acidic compartments in Sal-treated cells. However, tandem mCherry-GFP-LC3 assay indicated that the degradation of mCherry-GFP-LC3 is blocked by Sal. Furthermore, the protein degradation activity of lysosomes was inhibited, as demonstrated by the rate of long-lived protein degradation, DQ-BSA assay and measurement of cathepsin activity. Our data indicated that Sal has a relatively greater suppressant effect on autophagic flux in the ALDH⁺ population in HMLER cells than in the ALDH⁻ population; moreover, this differential effect on autophagic flux correlated with an increase in apoptosis in the ALDH⁺ population. ATG7 depletion accelerated the proapoptotic capacity of Sal in the ALDH⁺ population. Our findings provide new insights into how the autophagy-lysosomal pathway contributes to the ability of Sal to target CSCs in vitro.     

Differentially expressed miR-20, miR-21, miR-100, miR-125a and miR-146a as a potential biomarker for prostate cancer

Prostate cancer is the leading cause of death among men worldwide. Deregulation of microRNAs has been reported in many cancers. Expression of microRNAs miR-20a-5p, miR-21-5p, miR-100-5p, miR-125a-5p and miR-146a-5p in tissue blocks of histologically confirmed prostate cancer patients compared with BPH patients, to identify potential microRNA biomarker for prostate cancer. MicroRNA was isolated and expression was quantified by qRT-PCR using Taqman Advanced microRNA assay kits. The interactions between the microRNA:target mRNA were predicted by using bioinformatics tools such as miRwalk and miRTargetlink. The experimentally validated targets were analysed using gprofiler to identify their molecular function, biological process and related pathways. The expression analysis revealed that miR-21 and miR-100 were significantly down-regulated whereas miR-125a was up-regulated in prostate cancer patients. Comparative analysis of the expression levels with tumor grading reveal that miR-100 was significantly down-regulated (p?<?0.05) in high grade tumor, indicating that miR-100 associated with prostate cancer. ROC analysis revealed that combined analysis of down-regulated miRNAs (miR-21 and miR-100) shown AUC of 0.72 (95% CI 0.65–0.79). The combined analysis of all five miRNAs showed AUC of 0.87 (95% CI 0.81–0.92). The targets prediction analysis revealed several validated targets including BCL2, ROCK1, EGFR, PTEN, MTOR, NAIF1 and VEGFA. Our results provide evidence that combined analysis of all the five miRNAs as a panel can significantly improve the prediction level of the presence of prostate cancer and may be used as a potential diagnostic biomarker.

     

Prognostic value of miR-21 for prostate cancer: a systematic review and meta-analysis

Elevated levels of miR-21 expression are associated with many cancers, suggesting it may be a promising clinical biomarker. In prostate cancer (PCa), however, there is still no consensus about the usefulness of miR-21 as an indicator of disease progression. This systematic review and meta-analysis was conducted to investigate the value of miR-21 expression as a prognostic measurement in PCa patients. Medline (Ovid), EMBASE, Web of Science, Scopus and Cochrane Library databases were systematically searched for relevant publications between 2010 to 2021. Studies exploring the relationship between miR-21 expression, PCa prognosis and clinicopathological factors were selected for review. Those reporting hazard ratio (HR) and 95% confidence intervals (CIs) were subject to meta-analyses. Fixed-effect models were employed to calculated pooled HRs and 95% CIs. Risk of bias in each study was assessed using QUIPS tool. Certainty of evidence in each meta-analysis was assessed using GRADE guidelines. A total of 64 studies were included in the systematic review. Of these, 11 were eligible for inclusion in meta-analysis. Meta-analyses revealed that high miR-21 expression was associated with poor prognosis: HR = 1.58 (95% CI = 1.19–2.09) for biochemical recurrence, MODERATE certainty; HR = 1.46 (95% CI = 1.06–2.01) for death, VERY LOW certainty; and HR = 1.26 (95% CI = 0.70–2.27) for disease progression, VERY LOW certainty. Qualitative summary revealed elevated miR-21 expression was significantly positively associated with PCa stage, Gleason score and risk groups. This systematic review and meta-analysis suggests that elevated levels of miR-21 are associated with poor prognosis in PCa patients. miR-21 expression may therefore be a useful prognostic biomarker in this disease.     

Association between microRNA-146a, -499a and -196a-2 SNPs and non-small cell lung cancer: a case–control study involving 2249 subjects

MicroRNA (miR) acts as a negative regulator of gene expression. Many literatures have suggested that miRs may be involved in the process of cell proliferation, inflammation, oxidative stress, energy metabolism and epithelial–mesenchymal transition. Thus, miRs may be implicated in the occurrence of non-small cell lung cancer (NSCLC). In the current investigation, we included 2249 subjects (1193 NSCLC patients and 1056 controls) and designed a study to identify the relationship of miR-146a rs2910164 C/G, -499a rs3746444 A/G and -196a-2 rs11614913 T/C with the risk of NSCLC. The risk factors (e.g., body mass index (BMI), sex, smoking, drinking and age) was used to adjust the odds ratios (ORs) and 95% confidence intervals (CIs). After conducting a power value assessment, we did not confirm that the miR-single nucleotide polymorphisms (SNPs) genotypic distributions were different in NSCLC cases and controls. However, the association of miR-196a-2 rs11614913 with a decreased risk of NSCLC was identified in the female subgroup (adjusted P=0.005, power = 0.809 for TC vs. TT, and adjusted P=0.004, power = 0.849 for CC/TC vs. TT). In addition, gene–gene interaction analysis showed that rs11614913 TC/3746444 AA and rs11614913 CC/rs3746444 AA could also reduce the susceptibility to NSCLC (rs11614913 TC/rs3746444 AA vs. rs11614913 TT/rs3746444 AA, P=0.001, power = 0.912 and rs11614913 CC/rs3746444 AA vs. rs11614913 TT/rs3746444 AA, P=0.003, power = 0.836). In conclusion, in overall comparisons, we did not confirm that the rs2910164, rs3746444, and rs11614913 SNPs genotypic distributions were different in NSCLC cases and controls. However, this case–control study demonstrates that miR-196a-2 rs11614913 may be a protective factor for the development of NSCLC among female patients.     

Cloning of a cancer cell-producing hepatocyte growth factor, vascular endothelial growth factor, and interleukin-8 from gastric cancer cells

A cell colony (IM95m) that produces hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), and interleukin-8 (IL-8) was cloned from gastric cancer cells (IM95 cell line). In culture medium, the highest levels of HGF, VEGF, and IL-8 were about 1.1, 0.9, and 0.17 ng/ml culture medium at 3 d from 10(5) cells. IM95m may be useful in elucidating the role of tumor cells in angiogenesis.     

The expression level of surface marker Trop2 in gastric cancer stem-like cells

This study aims to prepare gastric cancer stem-like cells(GCSCs) using a serum-free suspension culture, then identify it preliminarily, and observe the expression level of Trop2. Serum-free DMEM/F12 medium and low-adhesion dish were used for suspended culture of gastric cancer (GC) cell lines MGC803. The morphological characteristics of cell spheres were observed by optical microscope; the positive rates of the CD44, CD54, EpCAM and Trop2 in MGC803 and MGC803-spheres were detected by FACS; the changes of the cell cycle in the MGC803-spheres were explored by FACS and compared with that in MGC803; the mRNA level of cancer stem cells(CSCs) regulatory genes and Trop2 in MGC803-spheres and MGC803 were detected by qRT-PCR. MGC803-spheres formed after MGC803 was cultured in serum-free medium for about 14 days; the levels of CD44, CD54, EpCAM and Trop2 in MGC803-spheres group were higher than those in MGC803 group (P<0.05). The G1 phase of cell cycle in the MGC803-spheres group was obviously lower than that in MGC803 group, and the S phase of the cell cycle in MGC803-spheres group was obviously higher than that in the MGC803 group (P<0.05). The mRNA level in the CSCs regulatory genes (Oct4, Snail, Nanog) and Trop2 in MGC803-spheres group were much higher than those in MGC803 group (P<0.05). MGC803-spheres could form in serum-free and suspension culture condition. The type of cells has the characteristic of CSCs, which appears in a higher proliferation state and over expression CSCs regulating genes and Trop2.     

川楝素对人胃癌细胞MKN-45中CTPS细胞蛇形成的影响及其机制*

目的:本研究旨在对川楝素(TSN)与胃癌细胞MKN-45中CTPS细胞蛇形成的联系进行初步探究。方法:以人胃癌细胞MKN-45为实验材料,设置7个处理组分别为:0、20、40、60、80、100、120 nmol/L TSN。每组3次重复,分别作用24 h、48 h、72 h,利用CCK-8法检测川楝素对MKN-45细胞增殖抑制作用,使用免疫荧光检测之后再通过激光共聚焦显微镜观察细胞内CTPS细胞蛇形态,qRT-PCR检测川楝素对MYC基因表达的影响。另外设置2个处理组为1 mmol/L DON和1 mmol/L MPA,每组3次重复,作用6 h然后采用免疫荧光检测细胞蛇形态。结果:免疫荧光结果显示,分别利用1 mmol/L DON和1 mmol/L MPA 处理MKN-45细胞后CTPS形成丝状的细胞蛇结构,意味着该细胞具有形成CTPS细胞蛇的能力;川楝素处理组的细胞增殖率明显低于0 nmol/L TSN组(P＜ 0.01);免疫荧光结果显示80 nmol/L的川楝素作用72 h时MKN-45细胞中CTPS细胞蛇形成数量最多;qRT-PCR检测结果显示,80 nmol/L川楝素作用24 h细胞内MYC表达明显降低(P＜0.05),48 h后细胞内MYC的表达量明显增多(P＜0.01)随后表达降低。结论:川楝素可能通过调节MYC的表达影响细胞内细胞蛇的组装。     

Circulating microRNA-133, microRNA-17 and microRNA-25 in serum and its potential diagnostic value in gastric cancer

Gastric cancer is one of the most common malignancies in the world and is considered as the most lethal gastrointestinal cancer. microRNAs (miRNAs) can be very important in detecting a disease at an early stage. The aim of this study was to investigate the microRNA-17 (miR-17), miR-25, and miR-133b in the serum of gastric cancer subjects. Serum samples were obtained from 120 gastric cancers and 102 healthy subjects. We evaluated expression levels of miR-17, miR-25 and miR-133b by quantitative real-time polymerase chain reaction. Our results showed that in the patients with gastric cancer, the expression level of miR-17 and miR-25 were significantly increased compared with the control group (P < 0.5), while the expression level of miR-133b was significantly decreased in patient groups compared with control cases (P < 0.5). It seems that expression of miRNAs in Iranian patients with gastric cancer is similar to other patients in other populations. These findings suggested that miR-17, miR-25 and miR-133b could be introduced as potential diagnostic candidates for the detection in gastric cancer patients in the early stage.     

miR-181b functions as an oncomiR in colorectal cancer by targeting PDCD4

Programmed cell death 4 (PDCD4) is a RNA-binding protein that acts as a tumor suppressor in many cancer types, including colorectal cancer (CRC). During CRC carcinogenesis, PDCD4 protein levels remarkably decrease, but the underlying molecular mechanism for decreased PDCD4 expression is not fully understood. In this study, we performed bioinformatics analysis to identify miRNAs that potentially target PDCD4. We demonstrated miR-181b as a direct regulator of PDCD4. We further showed that activation of IL6/STAT3 signaling pathway increased miR-181b expression and consequently resulted in downregulation of PDCD4 in CRC cells. In addition, we investigated the biological effects of PDCD4 inhibition by miR-181b both in vitro and in vivo and found that miR-181b could promote cell proliferation and migration and suppress apoptosis in CRC cells and accelerate tumor growth in xenograft mice, potentially through targeting PDCD4. Taken together, this study highlights an oncomiR role for miR-181b in regulating PDCD4 in CRC and suggests that miR-181b may be a novel molecular therapeutic target for CRC.     

miR-148a promoted cell proliferation by targeting p27 in gastric cancer cells

Accumulating evidence has shown that miRNAs are aberrantly expressed in human gastric cancer and crucial to tumorigenesis. Herein, we identified the role of miR-148a in gastric cell proliferation. miR-148a knockdown inhibited cell proliferation in gastric cancer cell lines. Conversely, miR-148a overexpression promoted cell proliferation and cell cycle progression. p27, a key inhibitor of cell cycle, was verified as the target of miR-148a, indicating miR-148a might downregulate p27 expression to promote gastric cell proliferation. Moreover, we confirmed that miR-148a expression was frequently and dramatically downregulated in human advanced gastric cancer tissues, and observed a good inverse correlation between miR-148a and p27 expression in tumor samples. Thus, our results demonstrated that miR-148a downregulation might exert some sort of antagonistic function in cell proliferation, rather than promote cell proliferation in gastric cancer.     

Divergent intracellular pathways regulate interleukin-1β-induced miR-146a and miR-146b expression and chemokine release in human alveolar epithelial cells

We have previously reported that IL-β-induced miR-146a and miR-146b expression negatively regulates IL-8 and RANTES release in human alveolar A549 epithelial cells. To determine the intracellular pathways that regulate this response, we demonstrate IL-1β-induced activation of the nuclear factor (NF)-κB, extracellular regulated kinase (ERK)-1/2, c-jun N-terminal kinase (JNK)-1/2 and p38 mitogen activated kinase (MAP) kinase pathways. Subsequent pharmacological studies show that IL-1β-induced miR-146a, IL-8 and RANTES production was regulated via NF-κB and JNK-1/2 whilst miR-146b expression was mediated via MEK-1/2 and JNK-1/2. These divergent intracellular pathways likely explain the differential expression and biological action of the miR-146 isoforms.