MiR-92a mediates AZD6244 induced apoptosis and G1-phase arrest of lymphoma cells by targeting Bim

Expression of miR-92a is associated with the prognosis in non-small cell lung cancer: An observation study

With the development of molecular biology technology, the discovery of microRNAs (miRNAs) has provided new ideas for the diagnosis, treatment, and prognosis of lung cancer and laid a foundation for the study of this malignancy. To assess the potential prognostic value of miR-92a as a new biomarker in non-small cell lung cancer (NSCLC) via clinical evaluation, a total of 100 patients with NSCLC admitted to the Respiratory and Intensive Care Department of Suining Central Hospital in Sichuan Province between August 2007 and April 2020 were retrospectively analyzed. The correlation between miR-92a expression and prognosis of patients with NSCLC was also evaluated in the present study. The expression level of miR-92a was measured by PT-PCR and in situ hybridization. Chi-square test was adopted to explore the relationship of miR-92a expression and clinical features. Kaplan-Meier survival curves were plotted to delineate the overall survival rate of patients with NSCLC. Cox regression analysis was performed to evaluate the prognostic significance of miR-92a expression in NSCLC. The miR-92a expression in NSCLC tissue samples was significantly higher than that in normal lung tissues (P < .001) and significantly correlated with the Eastern Cooperative Oncology Group score, histological type, and distant metastasis (P < .05). Survival curve revealed that patients with NSCLC and high miR-92a expression had relatively higher mortality than those with low PAK4 expression (P = .001). Cox regression analysis explained that miR-92a expression was associated with the prognosis of patients with NSCLC (HR = 1.8, 95% CI: 1.0-3.2, P = .036). In summary, miR-92a was highly expressed in NSCLC tissues and could act as a prognostic factor for patients with NSCLC. These results illustrate that miR-92a expression plays an important role in the invasion and metastasis of NSCLC, and miR-92a can be used as a new biomarker to determine the prognosis of this cancer.

Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects

Infants who are exclusively breastfed in the first six months of age receive adequate nutrients, achieving optimal immune protection and growth. In addition to the known nutritional components of human breast milk (HBM), i.e., water, carbohydrates, fats and proteins, it is also a rich source of microRNAs, which impact epigenetic mechanisms. This comprehensive work presents an up-to-date overview of the immunomodulatory constituents of HBM, highlighting its content of circulating microRNAs. The epigenetic effects of HBM are discussed, especially those regulated by miRNAs. HBM contains more than 1400 microRNAs. The majority of these microRNAs originate from the lactating gland and are based on the remodeling of cells in the gland during breastfeeding. These miRNAs can affect epigenetic patterns by several mechanisms, including DNA methylation, histone modifications and RNA regulation, which could ultimately result in alterations in gene expressions. Therefore, the unique microRNA profile of HBM, including exosomal microRNAs, is implicated in the regulation of the genes responsible for a variety of immunological and physiological functions, such as FTO, INS, IGF1, NRF2, GLUT1 and FOXP3 genes. Hence, studying the HBM miRNA composition is important for improving the nutritional approaches for pregnancy and infant's early life and preventing diseases that could occur in the future. Interestingly, the composition of miRNAs in HBM is affected by multiple factors, including diet, environmental and genetic factors.

Pro- and anti-apoptotic microRNAs are differentially regulated during estivation in Xenopus laevis

Xenopus laevis, the African clawed frog, undergoes seasonal estivation to survive periods of drought when its lake-bed habitats dry up. The frog can lose ∼30% of its total body water, leading to conditions of impaired blood flow and ischemia which risk cellular survival under these harsh conditions. MicroRNAs are short, noncoding, single-stranded RNAs 21-24 nt long that have been widely implicated in hypometabolic responses, and serve functions including apoptosis survival. The levels of three pro-apoptotic and four anti-apoptotic miRNAs were measured in liver and skeletal muscle of estivating X. laevis, and bioinformatic analysis was performed to verify potential mRNA targets of these miRNAs. Members of pro-apoptotic miRNAs miR-15a, miR-16, and miR-101 showed upregulation as a result of dehydration stress, while anti-apoptotic miRNAs miR-19b, miR-21, miR-92a, and miR-155 showed differential regulation between the two tissues. Together, these miRNAs act in a more diverse fashion than arbitrarily pro- or anti-apoptotic, and encompass functions ranging from the inhibition of cell proliferation through cell cycle arrest to the prevention of skeletal muscle atrophy.

The role of miRNAs in regulating the effect of prenatal cadmium exposure on ovarian granulosa cells in a transgenerational manner in female rats

Cadmium (Cd) is known to affect ovarian granulosa cells (GCs), but no information on the transgenerational effects of Cd on GCs. In this study, pregnant Sprague-Dawley (SD) rats were orally dosed with Cd from gestation day 1 until birth. F1 or F2 female rats were mated with untreated males to produce the F2 or F3 generation. In the F1 generation, apoptotic cell bodies were observed in the Cd-treated group but not in the F2 generation. Moreover, significant changes in B-cell lymphoma 2 (Bcl2) expression were observed in both generations. Additionally, the expression of microRNAs (miRNAs) was significantly changed based on microarray analysis. Specifically, miR-16-5p and miR-181b-5p were upregulated in F1 and F2 rats, while miR-92a-2-5p demonstrated different expression patterns between the two generations. In F3 generation, miR-16-5p and miR-92a-2-5p were down-regulated. Further, another experiment was used to show that miR-16-5p and miR-92a-2-5p regulated the Bcl2-induced apoptotic effect of Cd on GCs by the Human ovarian GC tumor line (COV434 cell line) miRNA-knockdown model Overall, the results indicate that prenatal Cd exposure has epigenetic transgenerational effect on GCs, Moreover, the underlying mechanism may involve interference with miR-16-5p and miR-92a-2-5p-mediated regulation of Bcl2 genes in offspring.

MicroRNA Expression Profiling of Normal and Malignant Human Colonic Stem Cells Identifies miRNA92a as a Regulator of the LRIG1 Stem Cell Gene

MicroRNAs (miRNAs) have a critical role in regulating stem cells (SCs) during development, and because aberrant expression of miRNAs occurs in various cancers, our goal was to determine if dysregulation of miRNAs is involved in the SC origin of colorectal cancer (CRC). We previously reported that aldehyde dehydrogenase (ALDH) is a marker for normal and malignant human colonic SCs and tracks SC overpopulation during colon tumorigenesis. MicroRNA expression was studied in ALDH-positive SCs from normal and malignant human colon tissues by Nanostring miRNA profiling. Our findings show that: (1) A unique miRNA signature distinguishes ALDH-positive CRC cells from ALDH-positive normal colonic epithelial cells, (2) Expression of four miRNAs (miRNA200c, miRNA92a, miRNA20a, miRNA93) are significantly altered in CRC SCs compared to normal colonic SCs, (3) miRNA92a expression is also upregulated in ALDH-positive HT29 CRC SCs as compared to ALDH-negative SCs, (4) miRNA92a targets the 3′UTR of LRIG1 SC gene, and (5) miRNA92a modulates proliferation of HT29 CRC cells. Thus, our findings indicate that overexpression of miRNA92a contributes to the SC origin of CRC. Strategies designed to modulate miRNA expression, such as miRNA92a, may provide ways to target malignant SCs and to develop more effective therapies against CRC.

Cell proliferation is induced in renal cell carcinoma through miR-92a-3p upregulation by targeting FBXW7

Renal cell carcinoma (RCC) is the most common type of kidney cancer whose incidence has gradually increased worldwide. MicroRNAs (miRNAs) represent a type of short endogenous non-coding RNA containing approximately 22 nucleotides, which are capable of regulating mRNAs at the post-transcriptional level in human cells. miRNAs have been demonstrated to mediate gene expression by influencing important regulatory genes. Accumulating evidence indicates that certain miRNAs are involved in RCC development. The present study investigated the underlying mechanism and functional role of miR-92a-3p in RCC cells using reverse transcription-quantitative polymerase chain reaction, western blotting, 3′ UTR luciferase assay, cell proliferation assay and soft agar assay. The results demonstrated that miR-92a-3p expression level is significantly upregulated in RCC tissues and cell lines; however, F-box and WD repeat domain containing 7 (FBXW7) expression level was significantly downregulated in RCC tissues and cell lines. Subsequently, whether FBXW7 could be considered as a direct target of miR-92a-3p in RCC cells was investigated. The results demonstrated that miR-92a-3p overexpression significantly promoted RCC cell proliferation and colony formation. Conversely, miR-92a-3p downregulation significantly inhibited RCC cell proliferation and colony formation. In addition, FBXW7 knockdown significantly enhanced RCC cell proliferation and colony formation. Conversely, FBXW7 overexpression significantly inhibited RCC cell proliferation and colony formation. Collectively, these results demonstrated that miR-92a-3p/FBXW7 pathway may represent a novel strategy and therapeutic target for RCC.

Upregulation of S100A9 contributes to the acquired resistance to BRAF inhibitors

BACKGROUNDS

Acquired resistance is a significant clinical challenge in targeted therapy of melanomas using BRAF inhibitors. We previously identified that downregulation of miR-92a-1-5p confers acquired resistance to BRAF inhibition using an miRNA array platform.

OBJECTIVE

In this study, we investigated the target genes of miR-92a-1-5p and their functional significance in BRAF inhibitor resistance.

METHODS

The miRNA target prediction data were combined with RNA-Seq data to identify possible target genes for miR-92a-1-5p. Cellular effects of target genes were further examined using siRNA knockdown, WST-1 assay, and immunoblotting analysis.

RESULTS

We selected S100 calcium-binding protein A9 (S100A9) as a possible target gene for functional validation. S100A9 knockdown abrogated resistance to PLX4720 in A375P/Mdr cells. This result was similar to those described earlier for miR-92a-1-5p, indicating that miR-92a-1-5p inhibits cell viability by targeting S100A9. S100A9 overexpression partially conferred PLX4720 resistance to A375P cells. We also demonstrated that MAPK re-activation does not contribute to the promotion of BRAF inhibitor resistance by S100A9.

CONCLUSION

Taken together, our results indicate that S100A9 might be functionally involved in development of resistance to BRAF inhibitors and might be a target for melanoma therapy in the future.

Locked nucleic acid inhibits miR-92a-3p in human colorectal cancer, induces apoptosis and inhibits cell proliferation

MicroRNAs (miRNAs) are a type of small noncoding RNAs that have a vital role in basic biological processes such as cellular growth, division and apoptosis. A change in the expression of miRNAs can induce many diseases. Recently, the role of miRNA in some of the cancers as a tumor suppressor and oncogene has been recognized. Several studies have proved that miR-92a-3p acts as an oncogene in colorectal cancer (CRC). We studied CRC by inhibiting miR-92a-3p in SW48 cells (human colorectal cancer cell line) that were transfected with locked nucleic acid (LNA). At different times, the expression level of miR-92a-3p, cell vitality, apoptosis and necrosis were studied by qRT-PCR, MTT, Annexin-V and propidiumiodide. Our results showed that the expression of miR-92a-3p and proliferation of SW48 cells were decreased, and also a high percentage of SW48 cells were exposed to apoptosis and necrosis (P⩽0.005). Our study showed that the inhibition of miR-92a-3p with LNA inhibited cell proliferation and induced apoptosis and necrosis in CRC.

Downregulation of miR-129-2 by promoter hypermethylation regulates breast cancer cell proliferation and apoptosis

Aberrant expression of the miR-129 family has been found in several types of cancer, yet its expression and potential biologic role in breast cancer remain largely unknown. In the present study, we found that miR-129-2 was consistently downregulated in the breast cancer specimens and cell lines. Overexpression of miR-129-2-3p markedly suppressed breast cancer cell proliferation and induced its apoptosis. In addition, a luciferase reporter assay revealed that miR-129-2-3p suppressed BCL2L2 expression. Furthermore, BCL2L2 was able to reverse miR-129-2-3p-mediated cell apoptosis, indicating that BCL2L2 plays a crucial role in mediating the tumor-suppressive role of miR-129-2-3p. Moreover, bisulfite DNA sequencing PCR (BSP) analysis identified that promoter hypermethylation was responsible for the downregulation of miR-129-2 in breast cancer. Collectively, our findings indicate that miR-129-2 is downregulated in breast cancer cells by promoter hypermethylation. Moreover, downregulation of miR-129-2 results in BCL2L2 overexpression and disease progression in breast cancer patients.

Expression and prognostic value of miR-92a in patients with gastric cancer

MicroRNA (miR)-92 expression is often aberrant in human cancers. However, its expression in gastric carcinoma and its relation to clinicopathological features and prognosis are unclear.Tissue microarrays were constructed from 180 patients with gastric cancer (GC), who were undergoing radical resection. MiR-92a expression was detected using miRNA-locked nucleic acid in situ hybridization, and its correlation with clinicopathological features and overall survival was analyzed. MiR-92a expression was decreased in 13.9 % (25/180) of GC, increased in 81.1 % (146/180), and unchanged in 5.0 % (9/180), compared with paracancerous normal tissue (P < 0.001). Univariate analysis showed that high miR-92a expression, tumor stage, tumor status, node status, and tumor size were significant negative prognostic predictors for overall survival in patients with GC (P < 0.001, P < 0.001, P = 0.008, P < 0.001, and P = 0.001, respectively). High miR-92a expression still remained a significant predictor of shorter survival in stage II (n = 56, P = 0.001) and stage III (n = 92, P = 0.009) GC. Multivariate regression analysis demonstrated that tumor status (hazard ratio [HR], 3.10; 95 % confidence interval [CI], 1.51-6.37; P = 0.002), stage (HR, 3.54; 95 % CI, 1.65-7.63; P = 0.000), lymph node metastasis (HR, 2.83; 95 % CI, 1.88-4.28; P = 0.000), high expression of miR-92a (HR, 2.94; 95 % CI, 2.01-4.31; P = 0.000), and tumor size (HR, 2.34; 95 % CI, 1.45-3.79; P = 0.002) predicted shorter OS.High expression of miR-92a compared with adjacent normal tissues was associated with shorter OS. MiR-92a may thus be useful for evaluating prognosis and may provide a novel treatment target in patients with GC.

MicroRNA-92a contributes to tumor growth of human hepatocellular carcinoma by targeting FBXW7

Deregulation of microRNA-92a (miR-92a) has been reported in several human cancers and is associated with prognosis of patients. However, the clinical significance of miR-92a and the underlying mechanisms involved in hepatocarcinogenesis remain to be determined. The aim of the present study was to determine the role of miR-92a in hepatocellular carcinoma (HCC). The results showed that the expression of miR-92a was upregulated in HCC tissues as compared with matched tumor-adjacent tissues. A high expression of miR-92a was observed in HCC cell lines as compared with a non-transformed hepatic cell line. The gain- and loss-of-function studies revealed that miR-92a significantly promoted proliferation and cell cycle transition from G1 to S phase, and inhibited apoptosis of HCC cell in vitro. In tumor‑bearing nude mice, the downregulation of miR-92a suppressed tumor growth of HCC in vivo. miR-92a was inversely correlated with F-box and WD repeat domain-containing 7 (FBXW7) expression in HCC tissues. Furthermore, miR-92a negatively regulated FBXW7 abundance in HCC cells. In the present study, FBXW7 was identified as a direct target of miR-92a. Notably, alterations of FBXW7 expression abrogated the effects of miR-92a on HCC cell proliferation, cell cycle and apoptosis. Clinical association analysis revealed that a high expression of miR-92a was correlated with poor prognostic characteristics of HCC. Notably, the high expression of miR-92a conferred a reduced 5-year overall survival (OS) and recurrence-free survival (RFS) of HCC patients. The multivariate Cox regression analysis demonstrated that miR-92a expression was an independent prognostic marker for predicting survival of HCC patients. In conclusion, the results of the present study suggested that miR-92a promotes the tumor growth of HCC by targeting FBXW7 and may serve as a novel prognostic biomarker and therapeutic target for HCC.

MiR-92a inhibits porcine ovarian granulosa cell apoptosis by targeting Smad7 gene

Smad7 has a key role in apoptosis of mammalian ovarian granulosa cells (GCs), as it antagonizes and fine-tunes transforming growth factor β (TGFβ) signaling. This study demonstrates that miR-92a regulates GC apoptosis in pig ovaries by targeting Smad7 directly. The expression level of miR-92a was down-regulated in atretic porcine follicles, whereas miR-92a expression led to inhibition of GC apoptosis. The Smad7 gene was identified as a direct target of miR-92a using a dual-luciferase reporter assay. Transfection of GCs with miR-92a mimics decreased Smad7 mRNA and protein levels, whereas expression of an miR-92a inhibitor in GCs had the opposite effect. In addition, knockdown of Smad7 prevented GC apoptosis in cells that expressed the miR-92a inhibitor.