miR-192 Regulates dihydrofolate reductase and cellular proliferation through the p53-microRNA circuit

Dynamic genomic changes in methotrexate-resistant human cancer cell lines beyond DHFR amplification suggest potential new targets for preventing drug resistance

BACKGROUND

Although DHFR gene amplification has long been known as a major mechanism for methotrexate (MTX) resistance in cancer, the early changes and detailed development of the resistance are not yet fully understood.

METHODS

We performed genomic, transcriptional and proteomic analyses of human colon cancer cells with sequentially increasing levels of MTX-resistance.

RESULTS

The genomic amplification evolved in three phases (pre-amplification, homogenously staining region (HSR) and extrachromosomal DNA (ecDNA)). We confirm that genomic amplification and increased expression of DHFR, with formation of HSRs and especially ecDNAs, is the major driver of resistance. However, DHFR did not play a detectable role in the early phase. In the late phase (ecDNA), increase in FAM151B protein level may also have an important role by decreasing sensitivity to MTX. In addition, although MSH3 and ZFYVE16 may be subject to different posttranscriptional regulations and therefore protein expressions are decreased in ecDNA stages compared to HSR stages, they still play important roles in MTX resistance.

CONCLUSION

The study provides a detailed evolutionary trajectory of MTX-resistance and identifies new targets, especially ecDNAs, which could help to prevent drug resistance. It also presents a proof-of-principal approach which could be applied to other cancer drug resistance studies.

MiR-34 by targeting p53 induces apoptosis and DNA damage in paclitaxel-resistant human oral squamous carcinoma cells

MicroRNA-34 (miR-34) is one the most important tumor suppressor miRNAs involving in the various aspects of oral cancer. The present study aimed to evaluate the effects of miR-34 restoration in OECM-1 oral cancer resistant to paclitaxel (OECM-1/PTX) and its underlying mechanisms through p53-mediated DNA damage and apoptosis. OECM-1 and OECM-1/PTX were transfected with miR-34 mimic and inhibitor. Cellular proliferation and apoptosis were evaluated through MTT assay and flow cytometry, respectively. The mRNA and protein expression levels of p53, p-glycoprotein (P-gp), ATM, ATR, CHK1, and CHK2 were assessed through qRT-PCR and western blotting. Rhodamin123 uptake assay was used to measure the P-gp activities. P53 expression was also suppressed by sing a siRNA transfection of cells. The expression levels of miR-34 were downregulated in OECM-1/PTX. Restoration of miR-34 led to increase in cytotoxic effects of paclitaxel in cells. In addition, the expression levels and activities of P-gp were reduced following miR-34 transfection. miR-34 transfection upregulated the p53, ATM, ATR, CHK1, and CHK2 expression levels in OECM-1/PTX cells. Furthermore, cells transfected with miR-34 showed higher levels of apoptosis. miR-34 restoration reverses paclitaxel resistance in OECM-1 oral cancer. The chemosensitive effects of miR-34 is mediated through increasing DNA damage and apoptosis in a p53 depended manner.

Serum-Circulating microRNAs in Sporadic Inclusion Body Myositis

BACKGROUND

Sporadic inclusion body myositis (s-IBM) represents a unique disease within idiopathic inflammatory myopathies with a dual myodegenerative-autoimmune physiopathology and a lack of an efficacious treatment. Circulating miRNA expression could expand our knowledge of s-IBM patho-mechanisms and provide new potential disease biomarkers. To evaluate the expression of selected pre-amplified miRNAs in the serum of s-IBM patients compared to those of a sex- and age-matched healthy control group, we enrolled 14 consecutive s-IBM patients and 8 sex- and age-matched healthy controls. By using two different normalization approaches, we found one downregulated and three upregulated miRNAs. hsa-miR-192-5p was significantly downregulated, while hsa-miR-372-3p was found to be upregulated more in the s-IBM patients compared to the level of the controls. The other two miRNAs had a very low expression levels (raw Ct data > 29). hsa-miR-192-5p and hsa-miR-372-3p were found to be significantly dysregulated in the serum of s-IBM patients. These miRNAs are involved in differentiation and regeneration processes, thus possibly reflecting pathological mechanisms in s-IBM muscles and potentially representing disease biomarkers.

Epigenetic Alterations from Barrett's Esophagus to Esophageal Adenocarcinoma

Barrett's esophagus (BE) is a disease entity that is a sequela of chronic gastroesophageal reflux disease that may result in esophageal adenocarcinoma (EAC) due to columnar epithelial dysplasia. The histological degree of dysplasia is the sole biomarker frequently utilized by clinicians. However, the cost of endoscopy and the fact that the degree of dysplasia does not progress in many patients with BE diminish the effectiveness of histological grading as a perfect biomarker. Multiple or more quantitative biomarkers are required by clinicians since early diagnosis is crucial in esophageal adenocancers, which have a high mortality rate. The presence of epigenetic factors in the early stages of this neoplastic transformation holds promise as a predictive biomarker. In this review, current studies on DNA methylations, histone modifications, and noncoding RNAs (miRNAs) that have been discovered during the progression from BE dysplasia to EAC were collated.

Development of 5-FU-modified tumor suppressor microRNAs as a platform for novel microRNA-based cancer therapeutics

MicroRNA (miRNAs) are pleiotropic post-transcriptional modulators of gene expression. Their inherently pleiotropic nature makes miRNAs strong candidates for the development of cancer therapeutics, yet despite their potential, there remains a challenge to deliver nucleic acid-based therapies into cancer cells. We developed a novel approach to modify miRNAs by replacing the uracil bases with 5-fluorouracil (5-FU) in the guide strand of tumor suppressor miRNAs, thereby combining the therapeutic effect of 5-FU with tumor-suppressive effect of miRNAs to create a potent, multi-targeted therapeutic molecule without altering its native RNAi function. To demonstrate the general applicability of this approach to other tumor-suppressive miRNAs, we screened a panel of 12 novel miRNA mimetics in several cancer types, including leukemia, breast, gastric, lung, and pancreatic cancer. Our results show that 5-FU-modified miRNA mimetics have increased potency (low nanomolar range) in inhibiting cancer cell proliferation and that these mimetics can be delivered into cancer cells without delivery vehicle both in vitro and in vivo, thus representing significant advancements in the development of therapeutic miRNAs for cancer. This work demonstrates the potential of fluoropyrimidine modifications that can be broadly applicable and may serve as a platform technology for future miRNA and nucleic acid-based therapeutics.

RacGAP1 promotes the malignant progression of cervical cancer by regulating AP-1 via miR-192 and p-JNK

Cervical cancer (CC) is the most frequently diagnosed genital tract cancer in females worldwide. Rac GTPase-activating protein 1 (RacGAP1) is one of the specific GTPase-activating proteins. As a novel tumor protooncogene, overexpression of RacGAP1 was related to the occurrence of various tumors, but its function in CC is still unclear. In this study, bioinformatics analyses showed that RacGAP1 might be a key candidate gene in the progression of CC. RacGAP1 was significantly overexpressed in CC tissues. High RacGAP1 expression was positively associated with poor prognosis. Downregulating RacGAP1 significantly inhibited the proliferation, migration, and invasion of CC cells, while overexpressing RacGAP1 had the opposite effects. Further research showed that miR-192, which plays as a tumor suppressor in CC, was identified as a downstream target of RacGAP1 in CC cells. miR-192 inhibition could partially rescue the decrease in cell proliferation, migration, and invasion caused by RacGAP1 downregulation. In opposite, miR-192 overexpression could decrease the promotion of malignant progression caused by RacGAP1 upregulation. Mechanism studies revealed that RacGAP1 could regulate the expression and phosphorylation of c-Jun, which was the component of AP-1, via miR-192 and p-JNK separately. These findings suggested that RacGAP1 promoted tumorigenicity, migration, and invasion of CC. Therefore, it represented a potential novel prognostic marker in CC and may probably be a therapeutic target.

ATR and CDK4/6 inhibition target the growth of methotrexate-resistant choriocarcinoma

Low-risk gestational trophoblastic neoplasia including choriocarcinoma is often effectively treated with Methotrexate (MTX) as a first line therapy. However, MTX resistance (MTX-R) occurs in at least ≈33% of cases. This can sometimes be salvaged with actinomycin-D but often requires more toxic combination chemotherapy. Moreover, additional therapy may be needed and, for high-risk patients, 5% still die from the multidrug-resistant disease. Consequently, new treatments that are less toxic and could reverse MTX-R are needed. Here, we compared the proteome/phosphoproteome of MTX-resistant and sensitive choriocarcinoma cells using quantitative mass-spectrometry to identify therapeutically actionable molecular changes associated with MTX-R. Bioinformatics analysis of the proteomic data identified cell cycle and DNA damage repair as major pathways associated with MTX-R. MTX-R choriocarcinoma cells undergo cell cycle delay in G1 phase that enables them to repair DNA damage more efficiently through non-homologous end joining in an ATR-dependent manner. Increased expression of cyclin-dependent kinase 4 (CDK4) and loss of p16^Ink4a in resistant cells suggested that CDK4 inhibition may be a strategy to treat MTX-R choriocarcinoma. Indeed, inhibition of CDK4/6 using genetic silencing or the clinically relevant inhibitor, Palbociclib, induced growth inhibition both in vitro and in an orthotopic in vivo mouse model. Finally, targeting the ATR pathway, genetically or pharmacologically, re-sensitised resistant cells to MTX in vitro and potently prevented the growth of MTX-R tumours in vivo. In short, we identified two novel therapeutic strategies to tackle MTX-R choriocarcinoma that could rapidly be translated into the clinic.

Targeting MicroRNA-192-5p, a Downstream Effector of NOXs (NADPH Oxidases), Reverses Endothelial DHFR (Dihydrofolate Reductase) Deficiency to Attenuate Abdominal Aortic Aneurysm Formation

[Figure: see text].

Simultaneous Assessment of MicroRNAs 126 and 192 in Diabetic Nephropathy Patients and the Relation of these MicroRNAs with Urinary Albumin

BACKGROUND AND OBJECTIVE

Diabetic nephropathy (DN) is a major determinant of end-stage renal disease (ESRD). Altered microRNA levels lead to serious chronic diseases, such as diabetes. We aimed to measure the expression levels of two microRNAs, microRNA126 and 192 in DN and investigate their connection with albuminuria levels.

METHODS

This study included 229 subjects (134 DN patients and 95 controls). Serum lipid profiles, glucose levels, glycated haemoglobin (HbA1c) levels, and renal functions were assayed. The microRNA126 and microRNA192 expression levels were determined by real-time PCR.

RESULTS

Patients with DN had higher weights, BMI values, glucose levels (P<0.001), HbA1c levels (P<0.001), urinary albumin-creatinine ratio (ACR) values (P<0.001), urea levels (P=0.002), and creatinine levels (P=0.004) and lower expression levels of both microRNA192 (P<0.001) and microRNA126 (P<0.001) than controls. MicroRNA126 expression was positively correlated with age, estimated glomerular filtration rate (eGFR) and microRNA192 expression but negatively correlated with blood sugar, HbA1c, urea, creatinine and ACR. MicroRNA192 had higher sensitivity (91%), specificity (94%), and area under the curve (AUC) (0.967) values than microRNA126 (sensitivity, 90%; specificity, 68%; AUC, 0.897) and thus can precisely diagnose DN.

CONCLUSION

Both MicroRNA126 and microRNA192 expression were obviously associated with DN and might determine the progression of the disease owing to prominent relation with macroalbuminuria.

Dysregulation of exosomal miR-192 and miR-194 expression in lung adenocarcinoma patients

Non-small cell lung cancer (NSCLC) is the main reason of cancer linked mortality and around 80% of cases diagnosed in advanced stage. Therefore current study designed to evaluate the deregulation of miRNA-194 and miRNA-192 in different body fluid of Non small cell lung cancer participants. Present study recruited newly diagnosed histopathologically confirmed. It was observed that the 40% NSCLC participants showed elevated miR-194 expression and 60% NSCLC participants showed reduced miR-194 expression in serum sample while in Bronchial wash, only 20% NSCLC participants showed elevated miR-194 expression while 80% showed reduced miR-194 expression (p = 0.003). It was found that the 54% NSCLC participants showed elevated miR-192 expression and 55% NSCLC participants showed reduced miR-192 expression in serum sample while In Bronchial wash sample, only 25% NSCLC participants showed high miR-192 expression while 75% showed low miR-192 expression (P = 0.0004). Expression of miR-194 was significantly associated with TNM stages (p < 0.0001, p < 0.0001), distant organ metastases (p < 0.0001, p < 0.0001), pathological grade (p = 0.0009, p = 0.0005) among serum sample and bronchial wash sample. Same observation was found with expression of miR-192 and it was significantly associated with TNM stages (p < 0.0001, p < 0.0001), distant organ metastases (p < 0.0001, p < 0.0001), pathological grade (p = 0.006, p = 0.001) among serum sample and bronchial wash sample. It was observed that the NSCLC participants who had high serum based miR-194 expression showed 22 months of overall median survival while low expression of serum based miR-194 expression showed 18 months of overall median survival. Present study suggests that decreased expression of miR-194 and miR-192 was significantly associated with different clinical features of NSCLC cases. However, significantly higher number of NSCLC cases showed low expression of miR-194 and miR-192 in bronchial lavage sample. Decreased poor overall survival was found to be associated with bronchial wash sample with respect to low miR-194 and miR-192 expression while NSCLC participants showed better overall survival with high miR-194 and miR-192 expression. This suggested decreased expression of miR-192 and miR-194 expression could be the potential prognostic marker among NSCLC participants.

Diagnostic and Prognostic Role of miR-192 in Different Cancers: A Systematic Review and Meta-Analysis

Introduction

It has been shown that miR-192 is abnormally expressed in a variety of cancer types and participates in different kinds of signaling pathways. The role of miR-192 in the diagnosis and prognosis of cancer has not been verified. This article is aimed at exploring the diagnostic and prognostic value of miR-192 through a systematic review and meta-analysis.

Methods

A systematic search was performed through PubMed, Embase, Web of Science, and Cochrane Library databases up to June 16, 2020. A total of 16 studies were enrolled in the meta-analyses, of which 11 articles were used for diagnostic meta-analysis and 5 articles were used for prognostic meta-analysis. The values of sensitivity and specificity using miR-192 expression as a diagnostic tool were pooled in the diagnostic meta-analysis. The hazard ratios (HRs) of overall survival (OS) with 95 confidence intervals (CIs) were extracted from the studies, and pooled HRs were evaluated in the prognostic meta-analysis. Eleven studies including 667 cancer patients and 514 controls met the eligibility criteria for the diagnostic meta-analysis. Five studies including 166 patients with high miR-192 expression and 236 patients with low miR-192 expression met the eligibility criteria for the prognostic meta-analysis.

Results

The overall diagnostic accuracy was as follows: sensitivity 0.79 (95%CI = 0.75-0.82), specificity 0.74 (95%CI = 0.64-0.82), positive likelihood ratio 3.03 (95%CI = 2.11-4.34), negative likelihood ratio 0.29 (95%CI = 0.23-0.37), diagnostic odds ratio 10.50 (95%CI = 5.89-18.73), and area under the curve ratio (AUC) 0.82 (95%CI = 0.78-0.85). The overall prognostic analysis showed that high expression of miR-192 in patients was associated with positive survival (HR = 0.62, 95%CI : 0.41-0.93, p = 0.020).

Conclusion

Our results revealed that miR-192 was a potential biomarker with good sensitivity and specificity in cancers. Moreover, highly expressed miR-192 predicted a good prognosis for patients.

TRIP13 promotes metastasis of colorectal cancer regardless of p53 and microsatellite instability status

Overexpression of TRIP13, a member of the AAA-ATPase family, is linked with various cancers, but its role in metastasis is unknown in colorectal cancer (CRC). In the current study, we investigated the role TRIP13 in experimental metastasis and its involvement in regulation of WNT/β-catenin and EGFR signaling pathways. Evaluation of formalin-fixed paraffin-embedded (FFPE) and frozen tissues of adenomas and CRCs, along with their corresponding normal samples, showed that TRIP13 was gradually increased in its phenotypic expression from adenoma to carcinoma and that its overexpression in CRCs was independent of patient's gender, age, race/ethnicity, pathologic stage, and p53 and microsatellite instability (MSI) status. Moreover, liver metastases of CRCs showed TRIP13 overexpression as compared to matched adjacent liver tissues, indicating the biological relevance of TRIP13 in CRC progression and metastasis. TRIP13 knockdown impeded colony formation, invasion, motility, and spheroid-forming capacity of CRC cells irrespective of their p53 and MSI status. Furthermore, xenograft studies demonstrated high expression of TRIP13 contributed to tumor growth and metastasis. Depletion of TRIP13 in CRC cells decreased metastasis and it was independent of the p53 and MSI status. Furthermore, TRIP13 interacted with a tyrosine kinase, FGFR4; this interaction could be essential for activation of the EGFR-AKT pathway. In addition, we demonstrated the involvement of TRIP13 in the Wnt signaling pathway and in the epithelial-mesenchymal transition. Cell-based assays revealed that miR-192 and PNPT1 regulate TRIP13 expression in CRC. Additionally, RNA sequencing of CRC cells with TRIP13 knockdown identified COL6A3, TREM2, SHC3, and KLK7 as downstream targets that may have functional relevance in TRIP13-mediated tumor growth and metastasis. In summary, our results demonstrated that TRIP13 promotes tumor growth and metastasis regardless of p53 and MSI status, and indicated that it is a target for therapy of CRC.

Histone methyltransferase SET8 is regulated by miR-192/215 and induces oncogene-induced senescence via p53-dependent DNA damage in human gastric carcinoma cells

Gastric cancer (GC) is the most common cancer throughout the world. Despite advances of the treatments, detailed oncogenic mechanisms are largely unknown. In our previous study, we investigated microRNA (miR) expression profiles in human GC using miR microarrays. We found miR-192/215 were upregulated in GC tissues. Then gene microarray was implemented to discover the targets of miR-192/215. We compared the expression profile of BGC823 cells transfected with miR-192/215 inhibitors, and HFE145 cells transfected with miR-192/-215 mimics, respectively. SET8 was identified as a proposed target based on the expression change of more than twofold. SET8 belongs to the SET domain-containing methyltransferase family and specifically catalyzes monomethylation of H4K20me. It is involved in diverse functions in tumorigenesis and metastasis. Therefore, we focused on the contributions of miR-192/215/SET8 axis to the development of GC. In this study, we observe that functionally, SET8 regulated by miR-192/215 is involved in GC-related biological activities. SET8 is also found to trigger oncogene-induced senescence (OIS) in GC in vivo and in vitro, which is dependent on the DDR (DNA damage response) and p53. Our findings reveal that SET8 functions as a negative regulator of metastasis via the OIS-signaling pathway. Taken together, we investigated the functional significance, molecular mechanisms, and clinical impact of miR-192/215/SET8/p53 in GC.

New signatures of poor CD4 cell recovery after suppressive antiretroviral therapy in HIV-1-infected individuals: involvement of miR-192, IL-6, sCD14 and miR-144

Up to 40% of newly diagnosed cases of HIV-1 infection are late diagnoses, with a profound decrease in CD4 cell counts in many cases. One-third of these individuals do not achieve optimal CD4 cell recovery (OR) after suppressive antiretroviral treatment (ART). This retrospective/longitudinal study of poor recovery (PR) included 79 HIV-1-infected individuals with CD4 count <200 cells/mm³ (25 PR and 54 OR) before ART. After suppressive ART, 21 PR and 24 OR individuals were further analysed, including paired samples. Selected miRs and plasma inflammatory markers were determined to investigate their potential predictive/diagnostic value for poor recovery. miR-192, IL-6 and sCD14 were independently associated with CD4 recovery before ART (p = 0.031, p = 0.007, and p = 0.008, respectively). The combination of these three factors returned a good discrimination (predictive value for PR) value of 0.841 (AUC, p < 0.001). After suppressive ART, miR-144 was independently associated with CD4 recovery (p = 0.017), showing a moderate discrimination value of 0.730 (AUC, p = 0.008) for PR. Our study provides new evidence on the relationship between miRs and HIV-1 infection that could help improve the management of individuals at HIV-1 diagnosis. These miRs and cytokines signature sets provide novel tools to predict CD4 cell recovery and its progression after ART.

5-fluorouracil and other fluoropyrimidines in colorectal cancer: Past, present and future

5-Fluorouracil (5-FU) is an essential component of systemic chemotherapy for colorectal cancer (CRC) in the palliative and adjuvant settings. Over the past four decades, several modulation strategies including the implementation of 5-FU-based combination regimens and 5-FU pro-drugs have been developed and tested to increase the anti-tumor activity of 5-FU and to overcome the clinical resistance. Despite the encouraging progress in CRC therapy to date, the patients' response rates to therapy continue to remain low and the patients' benefit from 5-FU-based therapy is frequently compromised by the development of chemoresistance. Inter-individual differences in the treatment response in CRC patients may originate in the unique genetic and epigenetic make-up of each individual. The critical element in the current trend of personalized medicine is the proper comprehension of causes and mechanisms contributing to the low or lack of sensitivity of tumor tissue to 5-FU-based therapy. The identification and validation of predictive biomarkers for existing 5-FU-based and new targeted therapies for CRC treatment will likely improve patients' outcomes in the future. Herein we present a comprehensive review summarizing options of CRC treatment and the mechanisms of 5-FU action at the molecular level, including both anabolic and catabolic ways. The main part of this review comprises the currently known molecular mechanisms underlying the chemoresistance in CRC patients. We also focus on various 5-FU pro-drugs developed to increase the amount of circulating 5-FU and to limit toxicity. Finally, we propose future directions of personalized CRC therapy according to the latest published evidence.

Novel BDNF-regulatory microRNAs in neurodegenerative disorders pathogenesis: An in silico study

Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor with various roles in the central nervous system neurogenesis, neuroprotection, and axonal guide. By attaching to Tropomyosin receptor kinase B (TrkB) receptor, this protein triggers downstream signaling pathways which lead to cellular growth, proliferation, survival, and neuroplasticity. Deregulation at mRNA level is involved in various central nervous system disorders including, Huntington, Alzheimer's, Multiple Sclerosis, and Amyotrophic Lateral Sclerosis diseases. Considering the importance of BDNF functions, deciphering the regulatory mechanisms controlling BDNF expression level could pave the way to develop more accurate and efficient treatments for neurological diseases. Among different regulatory systems, microRNAs (miRNAs) play prominent roles by targeting genes 3' untranslated regions. In this study, 127 validated and bioinformatic-predicted miRNAs with potentially regulatory roles in BDNF expression were analyzed. Various aspects of miRNAsö possible functions were assessed by bioinformatic online tools to find their potential regulatory functions in signaling pathways, neurological disorders, expression of transcription factors and miRNAs sponge. Analyzed data led to introduce 5 newly reported miRNAs that could regulate BDNF expression level. Finally, high throughput sequencing data from different brain regions and neurological disorders were analyzed to measure correlation of candidate miRNAs with BDNF level in experimental studies. In this study, a list of novel miRNAs with possible regulatory roles in BDNF expression level involving in different neurological disorders was introduced.

Roles Of EAAT1, DHFR, And Fetuin-A In The Pathogenesis, Progression And Prognosis Of Chondrosarcoma

Aims

Chondrosarcoma (CS) is a high-morbidity, relatively common bone malignancy without well-established biomarkers. The proteins EAAT1, DHFR, and fetuin-A have been investigated in many cancers, but their specific relationship to CS has not been reported. The present study examined EAAT1, DHFR, and fetuin-A expression in CS and the clinicopathological significance of these proteins in CS pathogenesis, progression, and prognosis.

Methods

EAAT1, DHFR, and fetuin-A protein levels in 80 CS and 25 chondroma specimens were measured by immunohistochemistry and related to histological and clinical factors with chi-squared tests. Following univariate survival analysis, ROC curves calculation, and multivariate analysis.

Results

EAAT1, DHFR, and fetuin-A expression levels were significantly higher in the CS group than in the chondroma group (p < 0.05). Their immunopositivity rates were significantly greater in tissues with moderate or poor tumor differentiation, AJCC stage III or IV, Enneking stage II or III, and metastasis (p<0.05 or p<0.01 or p<0.001). Kaplan–Meier survival analysis showed significantly shorter survival in patients with moderately or poorly differentiated tumors, AJCC stage III or IV CS, Enneking stage II or III CS, metastasis, invasion, or EAAT1, DHFR, and fetuin-A immunopositivity (p < 0.05 or p < 0.001). Cox regression analysis showed that moderate or poor tumor differentiation, AJCC stage III or IV, Enneking stage II or III, metastasis, invasion, and EAAT1, DHFR, or fetuin-A immunopositivity correlated negatively with postoperative survival and positively with mortality (p < 0.05). The AUCs for EAAT1, DHFR, and fetuin-A were 0.654 (95% CI: 0.532–0.776, p = 0.025), 0.638 (95% CI: 0.519–0.756, p = 0.039), and 0.670 (95% CI: 0.556–0.784, p = 0.011), respectively.

Conclusion

EAAT1, DHFR, and fetuin-A may be important biomarkers of the pathogenesis and progression of CS and predictors of its prognosis.

MicroRNA‑192 inhibits cell proliferation and induces apoptosis in human breast cancer by targeting caveolin 1

It has been demonstrated that microRNA-192 (miR-192) serves important roles in different cancer types, including breast cancer, prostate cancer and colorectal cancer. However, its biological role and function in breast cancer remains largely unknown. The present study aimed to determine the role of miR-192 in breast cancer. In the present study, one normal breast and two breast tumor cells lines were used, which included the normal mammary fibroblast cell line Hs578Bst, a more aggressive breast tumor cell line MDA-MB-231 and a less aggressive breast tumor cell line MCF-7. The effect of miR-192 on proliferation of breast cancer cells was detected with an MTT assay. Western blot analysis was performed to determine protein expression of caveolin 1 (CAV1). A lentiviral vector that overexpresses pre-miR-192 and control lentiviral packaging plasmids were used in the present study. The Student's t-test was performed to analyze the significance of differences between samples. In the present study, it was determined that the expression of miR-192 is downregulated in breast cancer, compared with the adjacent normal tissues. Overexpression of miR-192 significantly inhibited cell proliferation, and induced cell apoptosis and cell cycle arrest in MCF7 and MDA-MB-231 cells. Using a bioinformatics method, CAV1 was considered a potential target of miR-192. Furthermore, it was demonstrated that CAV1 is a direct target of miR-192 and its protein expression is negatively regulated by miR-192. Therefore, the present study demonstrated that miR-192 serves an important role as a regulator in breast cancer and the miR-192/CAV1 axis has a potential as a therapeutic target for treatment of breast cancer.

MicroRNA-125a inhibits tumorigenesis by targeting Smurf1 in colorectal carcinoma

Aberrant expression of microRNAs (miRNAs) may contribute to the initiation and development of multiple types of human cancer. Several miRNAs have been found to be strongly correlated with the diagnosis, progression, and prognosis of colorectal carcinoma (CRC), but the role of miR‐125a in CRC remains unclear. In the present study, the function of miR‐125a on the expression of Smad ubiquitin regulatory factor 1 (Smurf1) was investigated in vitro and in vivo. We verified that Smurf1 is a downstream target gene of miR‐125a and is involved in miR‐125a‐mediated regulation of CT26 cell (colon cancer cell) proliferation and migration. Overexpression of miR‐125a suppresses CT26 cell growth by inhibiting cell proliferation. Additionally, wound healing assays were performed to show that overexpression of miR‐125a significantly reduced CT26 cell migration, which was reversed by overexpression of Smurf1. In vivo, miR‐125a overexpression downregulated the expression of Ki67 and Smurf1, thus leading to a marked reduction in tumor growth. These results revealed that miR‐125a plays a critical role in CRC by directly targeting Smurf1, a finding that may facilitate the development of improved diagnostic and therapeutic techniques for CRC.

MicroRNAs, intestinal inflammatory and tumor

Colorectal cancer (CRC) is the third most malignant tumor. Inflammatory bowel disease (IBD) can increase the risk of colorectal cancer. And colitis-associated cancer (CAC) is a CRC subtype, representing the inflammation-related colorectal cancer. For the past decades, we have known that ectopic microRNA (miRNA) expression was involved in the pathogenesis of IBD and CRC, playing a pivotal role in the progression of inflammation to colorectal cancer. Thus, this review provides the recent advances in altered human tissue-specific miRNAs that contribute to IBD, CRC and CAC pathogenesis, diagnosis and treatment. Meanwhile, the potential utilization of miRNAs as novel therapeutic targets for the prevention of CRC was also discussed.

Translational Multi-Disciplinary Approach for the Drug and Gene Delivery Systems for Cancer Treatment

Over the last several decades, nanoparticulate delivery systems have emerged as advanced drug and gene delivery tools for cancer therapy. However, their translation into clinical use still poses major challenges. Even though many innovative nanoparticulate approaches have shown very positive results both in vitro and in vivo, few of them have found a place in clinical practice. Possible factors responsible for the existing gap in the translation of nanomedicine to clinical practice may include oversimplification of enhanced permeability and retention effect, lack of correlation between the in vivo animal data vs their translation in human, and challenging multiple biological steps experienced during systemic delivery of nanomedicine. Understanding these challenges and coming up with solutions to overcome them is an important step in effective translation of nanomedicine into clinical practice. This review focuses on advancements in the field of nanomedicine used for anti-cancer therapy, including passive targeting, active targeting, and stimuli-controlled delivery. The review further reveals some of the challenges that are currently faced by pharmaceutical scientists in translation of nanomedicine; these include lack of adequate models for preclinical testing that can predict efficacy in humans, absence of appropriate regulatory guidelines for their approval processes, and difficulty in scale-up of the manufacturing of nanodrug delivery systems. A better understanding of these challenges will help us in filling the gap between the bench and bedside in cancer therapy.

Central role of the p53 pathway in the noncoding-RNA response to oxidative stress

Oxidative stress plays a fundamental role in many conditions. Specifically, redox imbalance inhibits endothelial cell (EC) growth, inducing cell death and senescence. We used global transcriptome profiling to investigate the involvement of noncoding-RNAs in these phenotypes. By RNA-sequencing, transcriptome changes were analyzed in human ECs exposed to H₂O₂, highlighting a pivotal role of p53-signaling. Bioinformatic analysis and validation in p53-silenced ECs, identified several p53-targets among both mRNAs and long noncoding-RNAs (lncRNAs), including MALAT1 and NEAT1. Among microRNAs (miRNAs), miR-192-5p was the most induced by H₂O₂ treatment, in a p53-dependent manner. Down-modulated mRNA-targets of miR-192-5p were involved in cell cycle, DNA repair and stress response. Accordingly, miR-192-5p overexpression significantly decreased EC proliferation, inducing cell death. A central role of the p53-pathway was also confirmed by the analysis of differential exon usage: Upon H₂O₂ treatment, the expression of p53-dependent 5'-isoforms of MDM2 and PVT1 increased selectively. The transcriptomic alterations identified in H₂O₂-treated ECs were also observed in other physiological and pathological conditions where redox control plays a fundamental role, such as ECs undergoing replicative senescence, skeletal muscles of critical limb-ischemia patients and the peripheral-blood mononuclear cells of long-living individuals. Collectively, these findings indicate a prominent role of noncoding-RNAs in oxidative stress response.

Overexpression of microRNA‑101 causes anti‑tumor effects by targeting CREB1 in colon cancer

Accumulating evidence has demonstrated that aberrantly expressed microRNAs (miRNAs) are involved in the initiation and progression of numerous types of human cancer. Although a number of miRNAs have been demonstrated to be associated with the diagnosis, progression and prognosis of colon cancer, the function of miRNA‑101 (miR‑101) in colon cancer remains unclear, and the molecular mechanisms underlying the effects of miR‑101 in colon cancer require further investigation. The present study investigated the role of miR‑101 in colon cancer, and the results suggested that miR‑101 expression levels were significantly decreased in colorectal carcinoma tissues and in three types of colorectal cancer cell lines. Furthermore, overexpression of miR‑101 inhibited cell proliferation and migration in HT29 cells. The transcription factor cAMP responsive element binding protein 1 (CREB1) was identified to be a direct target of miR‑101 using a luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction analysis and western blot assay. miR‑101 overexpression in tumor xenografts in vivo decreased the expression levels of proliferating cell nuclear antigen and CREB1, and suppressed tumor growth. The present results suggested that miR‑101 may serve a role in colon cancer by directly targeting CREB1. Collectively, the present study may contribute to the development of improved diagnosis and prognostics for colon cancer.

microRNA-Mediated Tumor-Microbiota Metabolic Interactions in Colorectal Cancer

Worldwide, colorectal cancer (CRC) is one of the leading causes of cancer-related deaths. Recent advances in high-throughput technologies have shown that the gut microbiota may have a major influence on human health, including CRC. Nonetheless, how the gut microbiota interacts with tumor cells in CRC patients is largely unknown. Studies have shown that the microbiota fills in a variety of niche metabolic pathways that the host does not possess. For example, the microbiota produces butyrate, which provides the colon's epithelial cells with about 70% of their energy needs. The typically fast proliferation of tumor cells in CRC patients drastically alters the tumor's nutrient microenvironment. Those alterations correspond to the microbiota composition and functional changes. In tumor cells, a central mediator of metabolic changes is the aberrant expression of microRNAs (miRNAs). In this study, we explored recent insights into metabolic interactions between the microbiota and tumor cells in CRC pathobiology, focusing on the role of miRNAs. These observations support our view that miRNAs may also serve as mediators of the metabolites' effects.

iDEP: an integrated web application for differential expression and pathway analysis of RNA-Seq data

BACKGROUND

RNA-seq is widely used for transcriptomic profiling, but the bioinformatics analysis of resultant data can be time-consuming and challenging, especially for biologists. We aim to streamline the bioinformatic analyses of gene-level data by developing a user-friendly, interactive web application for exploratory data analysis, differential expression, and pathway analysis.

RESULTS

iDEP (integrated Differential Expression and Pathway analysis) seamlessly connects 63 R/Bioconductor packages, 2 web services, and comprehensive annotation and pathway databases for 220 plant and animal species. The workflow can be reproduced by downloading customized R code and related pathway files. As an example, we analyzed an RNA-Seq dataset of lung fibroblasts with Hoxa1 knockdown and revealed the possible roles of SP1 and E2F1 and their target genes, including microRNAs, in blocking G1/S transition. In another example, our analysis shows that in mouse B cells without functional p53, ionizing radiation activates the MYC pathway and its downstream genes involved in cell proliferation, ribosome biogenesis, and non-coding RNA metabolism. In wildtype B cells, radiation induces p53-mediated apoptosis and DNA repair while suppressing the target genes of MYC and E2F1, and leads to growth and cell cycle arrest. iDEP helps unveil the multifaceted functions of p53 and the possible involvement of several microRNAs such as miR-92a, miR-504, and miR-30a. In both examples, we validated known molecular pathways and generated novel, testable hypotheses.

CONCLUSIONS

Combining comprehensive analytic functionalities with massive annotation databases, iDEP ( http://ge-lab.org/idep/ ) enables biologists to easily translate transcriptomic and proteomic data into actionable insights.

Identification and profiling of microRNA between back and belly Skin in Rex rabbits (Oryctolagus cuniculus)

Skin is an important trait for Rex rabbits and skin development is influenced by many processes, including hair follicle cycling, keratinocyte differentiation and formation of coat colour and skin morphogenesis. We identified differentially expressed microRNAs (miRNAs) between the back and belly skin in Rex rabbits. In total, 211 miRNAs (90 upregulated miRNAs and 121 downregulated miRNAs) were identified with a |log₂ (fold change)|&gt;1 and <em>P</em>-value&lt;0.05. Using target gene prediction for the miRNAs, differentially expressed predicted target genes were identified and the functional enrichment and signalling pathways of these target genes were processed to reveal their biological functions. A number of differentially expressed miRNAs were found to be involved in regulation of the cell cycle, skin epithelium differentiation, keratinocyte proliferation, hair follicle development and melanogenesis. In addition, target genes regulated by miRNAs play key roles in the activities of the Hedgehog signalling pathway, Wnt signalling pathway, Osteoclast differentiation and MAPK pathway, revealing mechanisms of skin development. Nine candidate miRNAs and 5 predicted target genes were selected for verification of their expression by quantitative reverse transcription polymerase chain reaction. A regulation network of miRNA and their target genes was constructed by analysing the GO enrichment and signalling pathways. Further studies should be carried out to validate the regulatory relationships between candidate miRNAs and their target genes.

MiR-215-5p is a tumor suppressor in colorectal cancer targeting EGFR ligand epiregulin and its transcriptional inducer HOXB9

Growing evidence suggests that microRNAs are involved in the development and progression of colorectal cancer (CRC). In the present study, deregulation and functioning of tumor-suppressive miR-215-5p was evaluated in CRC. In total, 448 tumor tissues and 325 paired adjacent healthy tissues collected from Czech and Spain cohorts of CRC patients have been used for miR-215-5p expression analyses. A series of in vitro experiments have been performed using transient transfection of miR-215-5p mimics into four CRC cell lines to identify specific cellular processes affected by miR-215-5p. Further, the effects of miR-215-5p on tumor growth were evaluated in vivo using NSG mice and stable cell line overexpressing miR-215-5p. Target mRNAs of miR-215-5p were tested using luciferase assay and western blot analyses. We found that miR-215-5p is significantly downregulated in tumor tissues compared with non-tumor adjacent tissues and its decreased levels correlate with the presence of lymph node metastases, tumor stage, and shorter overall survival in CRC patients. Overexpression of miR-215-5p significantly reduced proliferation, clonogenicity, and migration of CRC cells, lead to cell cycle arrest in G2/M phase and p53-dependent induction of apoptosis. The ability of miR-215-5p to inhibit tumor growth was confirmed in vivo. Finally, we confirmed epiregulin and HOXB9 to be the direct targets of miR-215-5p. As epiregulin is EGFR ligand and HOXB9 is its transcriptional inducer, we suggest that the main molecular link between miR-215-5p and CRC cells phenotypes presents the EGFR signaling pathway, which is one of the canonical pathogenic pathways in CRC.

Predictive role of microRNA-related genetic polymorphisms in the pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer patients

In rectal cancer, a pathologic complete response (pCR) to pre-operative treatment is a favourable prognostic marker, but is reported in a minority of the patients. We aimed at identifying microRNA-related host genetic polymorphisms predictive of pCR.

A panel of 114 microRNA-related tagging polymorphisms was selected and analyzed on 265 locally advanced rectal cancer patients treated with neoadjuvant chemo-radiotherapy. Patients were stratified in two subgroups according to the radiotherapy dose (50.4Gy for 202 patients, 55.0Gy for 78 patients). Interactions among genetic and clinical-pathological variants were investigated by recursive partitioning analysis.

Only polymorphisms with a consistent significant effect in the two subgroups of patients were selected as predictive markers of pCR. The results were validated by bootstrap analysis. SMAD3-rs744910, SMAD3-rs745103, and TRBP-rs6088619 were associated to an increased chance of pCR (p=0.0153, p=0.0471, p=0.0125). DROSHA-rs10719 and SMAD3-rs17228212 had an opposite detrimental effect on pathological tumour response (p=0.0274, p=0.0049). Recursive partitioning analysis highlighted that a longer interval time between the end of radiotherapy and surgery increases the chance of pCR in patients with a specific combination of SMAD3-rs744910 and TRBP-rs6088619 genotypes.

This study demonstrated that microRNA-related host genetic polymorphisms can predict pCR to neo-adjuvant chemo-radiotherapy, and could be used to personalize the interval time between the end of radiotherapy and surgery.

Tumor suppressive function of microRNA-192 in acute lymphoblastic leukemia

Non-coding RNAs play a critical role in gene regulation in cancer cells. Reduced expression of microRNA-192 (miR-192) has been detected in many cancers. In this study, we investigated the role of miR-192 in cell proliferation and cell cycle control in NALM-6 cell line, a model of acute lymphoblastic leukemia (ALL). Cell cycle analysis by DNA content using propidium iodide staining and cell apoptosis analysis using Annexin V assay were carried out. Cell proliferation changes were monitored using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. In addition, the relative changes in P53, BAX, CASP3, and BCL-2 gene expression were determined by quantitative reverse transcription PCR. Overexpression of miR-192 resulted in cell proliferation arrest in ALL cells. After 72 and 96 hours of transduction, apoptosis was significantly increased in the cells transduced with miR-192-overexpressing virus compared with control cells. The expression of P53, BAX, and CASP3 increased after 48 hours of transduction in miR-192-overexpressing cells, but no change was observed in BCL-2 expression. The G0/S and G1/S ratio changed to 7.5 and 4.5, respectively, in the cells overexpressing miR-192 compared with controls. The results of our study suggest, for the first time, tumor suppressive effects of miR-192 in ALL cells.

Overcoming chemoresistance in cancer stem cells with the help of microRNAs in colorectal cancer

It has been recognized that acute resistance to chemotherapy mediated by post-transcriptional and translational control is crucial to influence response and survival in cancer treatment. Tumor cells are highly heterogeneous and have the ability to adapt a resistance phenotype through epigenetic regulations such as microRNAs. This poses a major challenge to the treatment of advanced stage colon cancer patients. Colon cancer stem cells have been identified as one of the major contributors to resistance of colon cancer to chemotherapy. Through various mechanisms, these cells are able to resist the effects of traditional chemotherapeutics. The challenge posed by these cells is further enhanced by their plastic nature, where cells can transition between non-stem cancer cells and cancer stem cells creating a moving target. In this editorial, we discuss some of the recent advancements in overcoming chemoresistance associated with colon cancer stem cells with the help of microRNAs.

A-to-I RNA Editing Up-regulates Human Dihydrofolate Reductase in Breast Cancer

Dihydrofolate reductase (DHFR) plays a key role in folate metabolism and is a target molecule of methotrexate. An increase in the cellular expression level of DHFR is one of the mechanisms of tumor resistance to methotrexate. The present study investigated the possibility that adenosine-to-inosine RNA editing, which causes nucleotide conversion by adenosine deaminase acting on RNA (ADAR) enzymes, might modulate DHFR expression. In human breast adenocarcinoma-derived MCF-7 cells, 26 RNA editing sites were identified in the 3'-UTR of DHFR. Knockdown of ADAR1 decreased the RNA editing levels of DHFR and resulted in a decrease in the DHFR mRNA and protein levels, indicating that ADAR1 up-regulates DHFR expression. Using a computational analysis, miR-25-3p and miR-125a-3p were predicted to bind to the non-edited 3'-UTR of DHFR but not to the edited sequence. The decrease in DHFR expression by the knockdown of ADAR1 was restored by transfection of antisense oligonucleotides for these miRNAs, suggesting that RNA editing mediated up-regulation of DHFR requires the function of these miRNAs. Interestingly, we observed that the knockdown of ADAR1 decreased cell viability and increased the sensitivity of MCF-7 cells to methotrexate. ADAR1 expression levels and the RNA editing levels in the 3'-UTR of DHFR in breast cancer tissues were higher than those in adjacent normal tissues. Collectively, the present study demonstrated that ADAR1 positively regulates the expression of DHFR by editing the miR-25-3p and miR-125a-3p binding sites in the 3'-UTR of DHFR, enhancing cellular proliferation and resistance to methotrexate.

miR-600 inhibits cell proliferation, migration and invasion by targeting p53 in mutant p53-expressing human colorectal cancer cell lines

Mutations of the tumor protein p53 gene, a tumor suppressor, are one of the most frequent genetic alterations observed in cancer. It has been reported that mutations in p53 result in the loss of wild-type p53 activity, and the gain of novel oncogenic properties that promote tumor growth and progression. Recent studies have demonstrated that a number of microRNAs (miRs) are involved in the post-transcriptional regulation of p53. The present study demonstrates that miR-600 is a direct negative regulator of p53 through binding a site in the 3' untranslated region of p53 mRNA in human colorectal cancer (CRC) cells. Overexpression of miR-600 by lentiviral-mediated transduction decreased endogenous levels of p53 protein and inhibited cell proliferation, migration and invasion in mutant p53-expressing human CRC cell lines (SW480, SW620 and DLD-1) in vitro. In addition, silencing of p53 with small interfering RNA led to a similar phenotype. Furthermore, overexpression of miR-600 or p53 knockdown suppressed the expression of matrix metalloproteinase 9, and promoted the expression of E-cadherin and β-catenin. The results of the current study demonstrate that miR-600 is an important negative regulator of p53, and suggest that targeting mutant p53 using lentiviral-mediated miR-600 overexpression is a promising therapeutic strategy for the treatment of CRCs with p53 mutations.

Expression analysis of microRNA as prognostic biomarkers in colorectal cancer

microRNA (miRNA) based biomarkers have unique advantages due to their critical regulatory function, superior stability, and relatively small number compared to mRNAs. A number of miRNAs play key roles in colon cancer stem cell chemoresistance and have clinical potential as prognostic biomarkers. The purpose of this study is to systematically validate the prognostic potential of miRNAs in colorectal cancer. In this study, we validated the prognostic potential of a panel of miRNAs using 205 stage II, III, and IV colorectal cancer specimens by qRT-PCR analysis. We cross validated our results using The Cancer Genome Atlas (TCGA) database. Many of the miRNAs we investigated have been functionally validated to be important in contributing to chemoresistance to 5-fluorouracil (5-FU) based chemotherapy. We determined that miR-16 is the most consistent miRNA for expression normalization in colorectal cancer. We have validated several miRNAs (miR-15b, miR-215, miR-145, miR-192, let-7g) that are significantly associated with progression free survival (PFS) and/or overall survival (OS) of colorectal cancer patients independent of tumor stage and age at diagnosis. These 5 miRNAs are significantly associated with OS of colorectal cancer even after tumor location (left side vs. right side) is adjusted for. Furthermore, the prognostic value of let-7g for overall survival was independently validated using the RNA-Seq results from TCGA colorectal cancer database. These results, taken together, establish a solid foundation towards miRNA based precision management of colorectal cancer.

A Comprehensive MicroRNA Expression Profile of Liver and Lung Metastases of Colorectal Cancer with Their Corresponding Host Tissue and Its Prognostic Impact on Survival

MicroRNAs are small non-coding RNAs with a length of 18–25 nucleotides. They can regulate tumor invasion and metastasis by changing the expression and translation of their target mRNAs. Their expression is substantially altered in colorectal cancer cells as well as in the adjacent tumor-associated stroma. Both of these compartments have a mutual influence on tumor progression. In the development of metastases, cancer cells initially interact with the host tissue. Therefore, compartment-specific expression signatures of these three locations—tumor, associated stroma, and host tissue—can provide new insights into the complex tumor biology of colorectal cancer. Frozen tissue samples of colorectal liver (n = 25) and lung metastases (n = 24) were laser microdissected to separate tumor cells and the adjacent tumor-associated stroma cells. Additionally, normal lung and liver tissue was collected from the same patients. We performed a microarray analysis in four randomly selected liver metastases and four randomly selected lung metastases, analyzing a total of 939 human miRNAs. miRNAs with a significant change >2-fold between the tumor, tumor stroma, and host tissue were analyzed in all samples using RT-qPCR (11 miRNAs) and correlated with the clinical data. We found a differential expression of several miRNAs between the tumor, the tumor-associated stroma, and the host tissue compartment. When comparing liver and lung metastases, miR-194 showed a 1.5-fold; miR-125, miR-127, and miR-192 showed a 2.5-fold; miR-19 and miR-215 a 3-fold; miR-145, miR-199-3, and miR-429 a 5-fold; miR-21 a 7-fold; and, finally, miR-199-5 a 12.5-fold downregulation in liver metastases compared to lung metastases. Furthermore miR-19, miR-125, miR-127, miR-192, miR-194, miR-199-5, and miR-215 showed a significant upregulation in the normal liver tissue compared to the normal lung tissue. Univariate analysis identified an association of poor survival with the expression of miR-125 (p = 0.05), miR-127 (p = 0.001), miR-145 (p = 0.005), miR-192 (p = 0.015), miR-194 (0.003), miR-199-5 (p = 0.008), miR-215 (p < 0.001), and miR-429 (p = 0.03) in the host liver tissue of the liver metastases. Colorectal liver and lung metastases have a unique miRNA expression profile. miRNA expression in the host tissue of colorectal liver metastases seems to be able to influence tumor progression and survival. These findings can be used in the development of tailored therapies.

Suppression of iASPP-dependent aggressiveness in cervical cancer through reversal of methylation silencing of microRNA-124

Derepression of wild-type p53 by suppressing its negative inhibitor iASPP (Inhibitor of apoptosis-stimulating protein of p53) represents a potential therapeutic option for cervical cancer (CC). Here, we reported a novel functional significance of iASPP upregulation in cervical tumorigenesis: iASPP acts as a key promoter of CC cell proliferation, epithelial-mesenchymal transition, invasion and cancer stemness, by interacting with p53 to suppress p53-mediated transcription of target genes and reducing p53-responsive microRNA-34a levels. Moreover, we demonstrate that miR-124, directly targeting iASPP, reduces expression of iASPP and attenuates CC cell growth and invasiveness. Low miR-124 expression is inversely correlated with increased expression of iASPP mRNA in CC tissues. In a cohort of 40 patients with CC, the low miR-124 expression was correlated with poor 5-year overall survival (P = 0.0002) and shorter disease-free survival 5-year (P = 0006). Treatment with the DNA methyltransferase inhibitor Zebularine increases miR-124 expression and retards CC cell growth and invasion with minimal toxicity to normal cells. Even at a non-toxic concentration, Zebularine was effective in suppressing CC cell invasion and migration. Altogether, the restoration of miR-124 reduces iASPP expression and leads to p53-dependent tumor suppression, suggesting a therapeutic strategy to treat iASPP-associated CC.

miR-192 suppresses leptomeningeal dissemination of medulloblastoma by modulating cell proliferation and anchoring through the regulation of DHFR, integrins, and CD47

Background

The main cause of death in medulloblastoma is recurrence associated with leptomeningeal dissemination. During this process, the role of microRNAs (miRs) in the acquisition of metastatic phenotype remains poorly understood. This study aimed to identify the miR involved in leptomeningeal dissemination and to elucidate its biological functional mechanisms.

Materials and methods

We analyzed the miR expression profiles of 29 medulloblastomas according to the presence of cerebrospinal fluid (CSF) seeding. Differentially expressed miRs (DEmiRs) were validated in 29 medulloblastoma tissues and three medulloblastoma cell lines. The biological functions of the selected miRs were evaluated using in vitro and in vivo studies.

Results

A total of 12 DEmiRs were identified in medulloblastoma with seeding, including miR-192. The reduced expression of miR-192 was confirmed in the tumor seeding group and in the medulloblastoma cells. Overexpression of miR-192 inhibited cellular proliferation by binding DHFR. miR-192 decreased cellular anchoring via the repression of ITGAV, ITGB1, ITGB3, and CD47. Animals in the miR-192-treated group demonstrated a reduction of spinal seeding (P < 0.05) and a significant survival benefit (P < 0.05).

Conclusions

Medulloblastoma with seeding showed specific DEmiRs compared with those without. miR-192 suppresses leptomeningeal dissemination of medulloblastoma by modulating cell proliferation and anchoring ability.

Molecular Biomarkers of Colorectal Cancer and Cancer Disparities: Current Status and Perspective

This review provides updates on the efforts for the development of prognostic and predictive markers in colorectal cancer based on the race/ethnicity of patients. Since the clinical consequences of genetic and molecular alterations differ with patient race and ethnicity, the usefulness of these molecular alterations as biomarkers needs to be evaluated in different racial/ethnic groups. To accomplish personalized patient care, a combined analysis of multiple molecular alterations in DNA, RNA, microRNAs (miRNAs), metabolites, and proteins in a single test is required to assess disease status in a precise way. Therefore, a special emphasis is placed on issues related to utility of recently identified genetic and molecular alterations in genes, miRNAs, and various "-omes" (e.g., proteomes, kinomes, metabolomes, exomes, methylomes) as candidate molecular markers to determine cancer progression (disease recurrence/relapse and metastasis) and to assess the efficacy of therapy in colorectal cancer in relation to patient race and ethnicity. This review will be useful for oncologists, pathologists, and basic and translational researchers.

Identification of miR-215 mediated targets/pathways via translational immunoprecipitation expression analysis (TrIP-chip)

Steady state mRNA expression profiling can identify the majority of miRNA targets. However, some translationally repressed miRNA targets are missed and thus not considered for functional validation. Therefore, analysis of mRNA translation can enhance miRNA target identification for functional studies. We have applied a unique approach to identify miRNA targets in a small number of cells. Actively translating mRNAs are associated with polyribosomes and newly synthesized peptide chains are associated with molecular chaperones such as HSP70s. Affinity capture beads were used to capture HSP70 chaperones associated with polyribosome complexes. The isolated actively translating mRNAs were used for high throughput expression profiling analysis. miR-215 is an important miRNA in colorectal cancer and loss of miR-215 is significantly associated with prognosis of this disease. miR-215 suppresses the expression of several key targets. We utilized the affinity capture approach to isolate miR-215 mediated mRNA target transcripts. This approach provides a unique way to identify targets regulated by non-coding RNAs and RNA binding proteins from a small number of cells.

Expression profiling and functional characterization of miR-192 throughout sheep skeletal muscle development

MicroRNAs (miRNAs) are evolutionarily conserved, small, non-coding RNAs that have emerged as key regulators of myogenesis. Here, we examined the miRNA expression profiles of developing sheep skeletal muscle using a deep sequencing approach. We detected 2,396 miRNAs in the sheep skeletal muscle tissues. Of these, miR-192 was found to be up-regulated in prenatal skeletal muscle, but was down-regulated postnatally. MiR-192 expression also decreased during the myogenic differentiation of sheep satellite cells (SCs). MiR-192 overexpression significantly attenuated SCs myogenic differentiation but promoted SCs proliferation, whereas miR-192 inhibition enhanced SCs differentiation but suppressed SCs proliferation. We found that miR-192 targeted retinoblastoma 1 (RB1), a known regulator of myogenesis. Furthermore, knockdown of RB1 in cultured cells significantly inhibited SCs myogenic differentiation but accelerated SCs proliferation, confirming the role of RB1 in myogenesis. Taken together, our findings enrich the ovine miRNA database, and outline the miRNA transcriptome of sheep during skeletal muscle development. Moreover, we show that miR-192 affects SCs proliferation and myogenic differentiation via down-regulation of RB1.

Hepatitis C virus infection stimulates transforming growth factor-β1 expression through up-regulating miR-192

The objective of this study was to determine the molecular mechanisms underlying chronic liver injury and fibrosis caused by hepatitis C virus (HCV). This study revealed that miR-192 expreßsion was induced by HCV infection without affecting viral replication. However, viral-induced miR-192 up-regulated transforming growth factor-ß1 (TGF-ß1) expreßsion in liver cells at transcriptional level. TGF-ß1 stimulation by HCV-induced miR-192 was caused through ZEB1 down-regulation and TGF-ß1 increased miR-192 level via positive feedback pathway. Increase in miR-192 expreßsion by HCV infection was due to HCV core protein released and/or expressed by viral infection. TGF-ß1 promoter activity was also increased by HCV core protein in liver cells. Taken together, HCV infection resulted in increased TGF-ß1 transcription in hepatocytes through ZEB1 down-regulation by HCV core-mediated miR-192 stimulation. Importantly, miR-192 inhibition with anti-miR-192 rescued ZEB1 expression down-regulated by HCV infection, thus reducing the level of TGF-ß1 expression increased by HCV infection in hepatocytes. These results suggest a novel mechanism of HCV-mediated liver fibrogenesis with miR-192 being a potential molecular target to ameliorate viral pathogenesis.

microRNA-192 suppresses the expression of the farnesoid X receptor

Farnesoid X receptor (FXR, NR1H4) plays an important role in the regulation of bile acid homeostasis in liver and intestine and may exert protective effects against certain forms of cancer such as colon carcinoma. However, the role of FXR in cell growth regulation, apoptosis, and carcinogenesis is still controversial. Similar to FXR, microRNA-192 (miR-192) is mainly expressed in the liver and colon and plays an important role in the pathogenesis of colon carcinoma. In this study, we investigated the extent to which FXR is regulated by miR-192. Two in silico-predicted binding sites for miR-192-3p within the NR1H4-3' untranslated region (UTR) were examined in vitro by luciferase reporter assays. Wild-type and mutated forms of the NR1H4-3'UTR were subcloned into a pmirGLO vector and cotransfected into Huh-7 cells with miR-192-3p. To study the effects of miR-192 on the expression of FXR, FXR target genes and cell proliferation, Huh-7 and Caco-2 cells were transfected with miR-192-5p and -3p mimics or antagomirs. In addition, the correlation between FXR and miR-192 expression was studied by linear regression analyses in colonic adenocarcinoma tissue from 27 patients. MiR-192-3p bound specifically to the NR1H4-3'UTR and significantly decreased luciferase activity. Transfection with miR-192 led to significant decreases in NR1H4 mRNA and protein levels as well as the mRNA levels of the FXR-inducible bile acid transporters OSTα-OSTβ and OATP1B3. Significant inverse correlations were detected in colonic adenocarcinoma between NR1H4 mRNA and miR-192-3p expression. In summary, microRNA-192 suppresses the expression of FXR and FXR target genes in vitro and in vivo.

The miRacle in Pancreatic Cancer by miRNAs: Tiny Angels or Devils in Disease Progression

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with increasing incidence and high mortality. Surgical resection is the only potentially curative treatment of patients with PDAC. Because of the late presentation of the disease, about 20 percent of patients are candidates for this treatment. The average survival of resected patients is between 12 and 20 months, with a high probability of relapse. Standard chemo and radiation therapies do not offer significant improvement of the survival of these patients. Furthermore, novel treatment options aimed at targeting oncogenes or growth factors in pancreatic cancer have proved unsuccessful. Thereby, identifying new biomarkers that can detect early stages of this disease is of critical importance. Among these biomarkers, microRNAs (miRNAs) have supplied a profitable recourse and become an attractive focus of research in PDAC. MiRNAs regulate many genes involved in the development of PDAC through mRNA degradation or translation inhibition. The possibility of intervention in the molecular mechanisms of miRNAs regulation could begin a new generation of PDAC therapies. This review summarizes the reports describing miRNAs involvement in cellular processes involving pancreatic carcinogenesis and their utility in diagnosis, survival and therapeutic potential in pancreatic cancer.