Molecular risk stratification of acute myeloid leukemia (AML) is largely based on genetic markers. However, epigenetic changes, including DNA methylation, deregulate gene expression and may also have prognostic impact. We evaluated the clinical relevance of integrating DNA methylation and genetic information in AML.
Next-generation sequencing analysis of methylated DNA identified differentially methylated regions (DMRs) associated with prognostic mutations in older (≥ 60 years) cytogenetically normal (CN) patients with AML (n = 134). Genes with promoter DMRs and expression levels significantly associated with outcome were used to compute a prognostic gene expression weighted summary score that was tested and validated in four independent patient sets (n = 355).
In the training set, we identified seven genes (CD34, RHOC, SCRN1, F2RL1, FAM92A1, MIR155HG, and VWA8) with promoter DMRs and expression associated with overall survival (OS; P ≤ .001). Each gene had high DMR methylation and lower expression, which were associated with better outcome. A weighted summary expression score of the seven gene expression levels was computed. A low score was associated with a higher complete remission (CR) rate and longer disease-free survival and OS (P < .001 for all end points). This was validated in multivariable models and in two younger (< 60 years) and two older independent sets of patients with CN-AML. Considering the seven genes individually, the fewer the genes with high expression, the better the outcome. Younger and older patients with no genes or one gene with high expression had the best outcomes (CR rate, 94% and 87%, respectively; 3-year OS, 80% and 42%, respectively).
A seven-gene score encompassing epigenetic and genetic prognostic information identifies novel AML subsets that are meaningful for treatment guidance.
Barrett's esophagus (BE) is characterized by the native stratified squamous epithelium (N) lining the esophagus being replaced by a columnar epithelium with intestinal differentiation (Barrett's mucosa; BM). BM is considered as the main risk factor for esophageal adenocarcinoma (Barrett's adenocarcinoma; BAc). MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting messenger RNAs and they are reportedly dysregulated in BM. To test the hypothesis that a specific miRNA expression signature characterizes BM development and progression, we performed miRNA microarray analysis comparing native esophageal mucosa with all the phenotypic lesions seen in the Barrett's carcinogenic process. Specimens were collected from 14 BE patients who had undergone esophagectomy, including: 14 with N, 14 with BM, 7 with low-grade intraepithelial neoplasia, 5 with high-grade intra-epithelial neoplasia and 11 with BAc. Microarray findings were further validated by quantitive real-time polymerase chain reaction and in situ hybridization analyses using a different series of consecutive cases (162 biopsy samples and 5 esophagectomies) of histologically proven, long-segment BE. We identified a miRNA signature of Barrett's carcinogenesis consisting of an increased expression of 6 miRNAs and a reduced expression of 7 miRNAs. To further support these results, we investigated target gene expression using the Oncomine database and/or immunohistochemical analysis. We found that target gene expression correlated significantly with miRNA dysregulation. Specific miRNAs are directly involved in BE progression to cancer. miRNA profiling significantly expands current knowledge on the molecular history of Barrett's carcinogenesis, also identifying molecular markers of cancer progression.
miRNA; Barrett's esophagus; gene target; expression signature
Analyses of microRNA expression profiles have shown that many microRNAs are expressed aberrantly and correlate with tumorigenesis, progression, and prognosis of various haematological and solid tumours. We aimed to assess the relation between microRNA expression and progression and prognosis of gastric cancer.
353 gastric samples from two independent subsets of patients from Japan were analysed by microRNA microarray. MicroRNA expression patterns were compared between non-tumour mucosa and cancer samples, graded by diffuse and intestinal histological types and by progression-related factors (eg, depth of invasion, metastasis, and stage). Disease outcome was calculated by multivariable regression analysis to establish whether microRNAs are independent prognostic factors.
In 160 paired samples of non-tumour mucosa and cancer, 22 microRNAs were upregulated and 13 were downregulated in gastric cancer; 292 (83%) samples were distinguished correctly by this signature. The two histological subtypes of gastric cancer showed different microRNA signatures: eight microRNAs were upregulated in diffuse-type and four in intestinal-type cancer. In the progression-related signature, miR-125b, miR-199a, and miR-100 were the most important microRNAs involved. Low expression of let-7g (hazard ratio 2·6 [95% CI 1·3–4·9]) and miR-433 (2·1 [1·1–3·9]) and high expression of miR-214 (2·4 [1·2–4·5]) were associated with unfavourable outcome in overall survival independent of clinical covariates, including depth of invasion, lymph-node metastasis, and stage.
MicroRNAs are expressed differentially in gastric cancers, and histological subtypes are characterised by specific microRNA signatures. Unique microRNAs are associated with progression and prognosis of gastric cancer.
National Cancer Institute.
Infection by the human papillomavirus (HPV) is a cause of cervical intraepithelial neoplasia (CIN) and cancer. microRNA (miRNA) in situ analysis of the transformation zone epithelia, the site of initial cervical HPV infection, showed that miRNAs let-7c, — 99a, 26a, and 125b were the most abundantly expressed. In situ testing of CIN 1 showed a dramatic reduction in miR-125b expression in the koilocytes, the cytologic marker of productive HPV infection. A marked reduction in miR-125b was likewise observed in the HPV-infected cells of the condyloma acuminatum, verruca vulgaris, and epidermodysplasia verruciformis. Reverse transcriptase in situ polymerase chain reaction (PCR) showed that the pre-miRNA 125b was present in the koilocyte, suggesting direct inactivation of the mature miRNA. HEK cells transfected with only the antimiR-125b showed perinuclear halos equivalent to HPV-infected koilocytes. NIH 3T3 cells transfected with the HPV 16 full-length genome and mimetic miR-125b showed a marked reduction in viral DNA and protein synthesis by quantitative PCR and in situ-based analyses, respectively (P=0.002). Alternatively, cotransfection with anti-miR-125b and HPV 16 markedly increased HPV DNA (P=0.002). Sequence analyses showed strong homology between L2 of different HPV genotypes and miR-125b. Transfection with HPV 16 L2 resulted in a marked reduction in miR-125b levels in the NIH 3T3 cells. HPV L2-induced inactivation of miR-125b is associated with the classic cytologic changes of the koilocyte, and the exogenous application of mimetic miR-125b markedly inhibits HPV DNA synthesis.
human papillomavirus; microRNA; in situ hybridization; L2
We analyzed the in situ molecular correlates of infection from cancer patients treated with reovirus. Melanoma, colorectal, and ovarian cancer samples from such patients showed variable infection of the cancer cells but not the intermingled benign cells. RT in situ PCR showed most cancer cells contained the viral genome with threefold less having productive viral infection as documented by either tubulin or reoviral protein co-expression. Productive infection in the cancer cells was strongly correlated with co-expression of p38 and caspase-3 as well as apoptosis-related death (P<0.001). The cancer cell apoptotic death was due to a marked viral-induced inhibition of microRNA-let-7d that, in turn, upregulated caspase-3 activity. In summary, reovirus shows a striking tropism to cancer cells in clinical samples. A rate-limiting factor of reovirus-induced cancer cell death is productive viral infection that operates via the marked reduction of microRNA-let-7d and concomitant elevated caspase-3 expression.
apoptosis; caspase-3; microRNA-let-7d; PKR; Ras; reovirus
Emerging data demonstrate important roles for the TYRO3/AXL/MERTK receptor tyrosine kinase (TAM RTK) family in diverse cancers. We investigated the prognostic relevance of GAS6 expression, encoding the common TAM RTK ligand, in 270 adults (n=71 aged <60 years; n=199 aged ≥60 years) with de novo cytogenetically normal acute myeloid leukemia (CN-AML). Patients expressing GAS6 (GAS6+), especially those aged ≥60 years, more often failed to achieve a complete remission (CR). In all patients, GAS6+ patients had shorter disease-free (DFS) and overall (OS) survival than patients without GAS6 expression (GAS6−). After adjusting for other prognostic markers, GAS6+ predicted CR failure (P=0.02), shorter DFS (P=0.004) and OS (P=0.04). To gain further biologic insights, we derived a GAS6-associated gene-expression signature (P<0.001) that in GAS6+ patients included overexpressed BAALC and MN1, known to confer adverse prognosis in CN-AML, and overexpressed CXCL12, encoding stromal cell-derived factor, and its receptor genes, CXCR4 and CXCR7. This study reports for the first time that GAS6 expression is an adverse prognostic marker in CN-AML. Although GAS6 decoy receptors are not yet available in the clinic for GAS6+ CN-AML therapy, potential alternative therapies targeting GAS6+-associated pathways, e.g., CXCR4 antagonists may be considered for GAS6+ patients to sensitize them to chemotherapy.
GAS6; acute myeloid leukemia; prognosis
•Low expression of miR501-5p correlates with good prognosis for patients with ccRCC.•miRNA501-5p downregulation stimulates apoptosis by p53 activation.•miR501-5p upregulation promotes cell proliferation and survival.•Increased cell growth occurs by activation of mTOR kinase and MDM2 expression.•This miRNA modulates apoptosis/cell growth, making it a prognostic biomarker for ccRCC.
Renal cell carcinoma is a common neoplasia of the adult kidney that accounts for about 3% of adult malignancies. Clear cell renal carcinoma is the most frequent subtype of kidney cancer and 20–40% of patients develop metastases. The absence of appropriate biomarkers complicates diagnosis and prognosis of this disease. In this regard, small noncoding RNAs (microRNAs), which are mutated in several neoplastic diseases including kidney carcinoma, may be optimal candidates as biomarkers for diagnosis and prognosis of this kind of cancer. Here we show that patients with clear cell kidney carcinoma that express low levels of miR501-5p exhibited a good prognosis compared with patients with unchanged or high levels of this microRNA. Consistently, in kidney carcinoma cells the downregulation of miR501-5p induced an increased caspase-3 activity, p53 expression as well as decreased mTOR activation, leading to stimulation of the apoptotic pathway. Conversely, miR501-5p upregulation enhanced the activity of mTOR and promoted both cell proliferation and survival. These biological processes occurred through p53 inactivation by proteasome degradation in a mechanism involving MDM2-mediated p53 ubiquitination. Our results support a role for miR501-5p in balancing apoptosis and cell survival in clear cell renal carcinoma. In particular, the downregulation of microRNA501-5p promotes a good prognosis, while its upregulation contributes to a poor prognosis, in particular, if associated with p53 and MDM2 overexpression and mTOR activation. Thus, the expression of miR501-5p is a possible biomarker for the prognosis of clear cell renal carcinoma.
ccRCC, clear cell renal cell carcinoma; MDM2, mouse double minute 2 homolog; mTOR, mammalian target of rapamycin; pRCC, papillary renal cell carcinoma; MicroRNA501-5p; mTOR signaling; p53; Apoptosis; Cell survival
Gliomas represent a disparate group of tumours for which there are to date no cure. Thus, there is a recognized need for new diagnostic and therapeutic approaches based on increased understanding of their molecular nature. We performed the comparison of the microRNA (miRNA) profile of 8 WHO grade II gliomas and 24 higher grade tumours (2 WHO grade III and 22 glioblastomas) by using the Affymetrix GeneChip miRNA Array v. 1.0. A relative quantification method (RT-qPCR) with standard curve was used to confirm the 22 miRNA signature resulted by array analysis. The prognostic performances of the confirmed miRNAs were estimated on the Tumor Cancer Genome Atlas (TCGA) datasets. We identified 22 miRNAs distinguishing grade II gliomas from higher grade tumours. RT-qPCR confirmed the differential expression in the two patients' groups for 13 out of the 22 miRNAs. The analysis of the Glioblastoma Multiforme (GBM) and Lower Grade Glioma (LGG) datasets from TCGA demonstrated the association with prognosis for 6 of those miRNAs. Moreover, in the GBM dataset miR-21 and miR-210 were predictors of worse prognosis in both univariable and multivariable Cox regression analyses (HR 1.19, p = 0.04, and HR 1.18, p = 0.029 respectively). Our results support a direct contribution of miRNAs to glioma cancerogenesis and suggest that miR-21 and miR-210 may play a role in the aggressive clinical behaviour of glioblastomas.
There are 481 ultra-conserved regions (UCRs) longer than 200 bases in the genomes of human, mouse and rat. These DNA sequences are absolutely conserved and show 100% identity with no insertions or deletions. About half of these UCRs are reported as transcribed and many correspond to long non-coding RNAs (lncRNAs).
We used custom microarrays with 962 probes representing sense and antisense sequences for the 481 UCRs to examine their expression across 374 normal samples from 46 different tissues and 510 samples representing 10 different types of cancer. The expression in embryonic stem cells of selected UCRs was validated by real time PCR.
We identified tissue selective UCRs and studied UCRs in embryonic and induced pluripotent stem cells. Among the normal tissues, the uc.283 lncRNA was highly specific for pluripotent stem cells. Intriguingly, the uc.283-plus lncRNA was highly expressed in some solid cancers, particularly in one of the most untreatable types, glioma.
Our results suggest that uc.283-plus lncRNA might have a role in pluripotency of stem cells and in the biology of glioma.
Electronic supplementary material
The online version of this article (doi:10.1186/s13073-014-0076-4) contains supplementary material, which is available to authorized users.
We performed genome-wide microRNA-sequencing (miRNA-seq) in primary cancer tissue from lung adenocarcinoma patients to identify markers for the presence of lymph node metastasis.
Markers for lymph node metastasis identified by sequencing were validated in a separate cohort using QPCR. After additional validation in the TCGA dataset, functional characterization studies were performed in vitro.
MiR-31 was upregulated in lung adenocarcinoma tissues from patients with lymph node metastases compared to those without lymph node metastases. We confirmed miR-31 to be up-regulated in lymph node positive patients in a separate patient cohort (p=0.009, t-test), and to be expressed higher in adenocarcinoma tissue than in matched normal adjacent lung tissues (p<0.0001, paired t-test). MiR-31 was then validated as a marker for lymph node metastasis in an external validation cohort of 233 lung adenocarcinoma cases of the TCGA (p=0.031, t-test). In vitro functional assays showed that miR-31 increases cell migration, invasion, and proliferation in an ERK1/2 signaling dependent manner. Of note, miR-31 was a significant predictor of survival in a multivariate cox regression model even when controlling for cancer staging. Exploratory in silico analysis showed that low expression of miR-31 is associated with excellent survival for T2N0 patients.
We applied microRNA-seq to study microRNomes in lung adenocarcinoma tissue samples for the first time and identified potentially a microRNA predicting the presence of lymph node metastasis and survival outcomes in lung adenocarcinoma patients.
miRNA-seq; lung adenocarcinoma; metastasis; nodal stage; biomarker
Barrett's esophagus (BE) involves a metaplastic replacement of native esophageal squamous epithelium (Sq) by columnar-intestinalized mucosa, and it is the main risk factor for Barrett-related adenocarcinoma (BAc). Ultra-conserved regions (UCRs) are a class non-coding sequences that are conserved in humans, mice and rats. More than 90% of UCRs are transcribed (T-UCRs) in normal tissues, and are altered at transcriptional level in tumorigenesis. To identify the T-UCR profiles that are dysregulated in Barrett's mucosa transformation, microarray analysis was performed on a discovery set of 51 macro-dissected samples obtained from 14 long-segment BE patients. Results were validated in an independent series of esophageal biopsy/surgery specimens and in two murine models of Barrett's esophagus (i.e. esophagogastric-duodenal anastomosis). Progression from normal to BE to adenocarcinoma was each associated with specific and mutually exclusive T-UCR signatures that included up-regulation of uc.58-, uc.202-, uc.207-, and uc.223- and down-regulation of uc.214+. A 9 T-UCR signature characterized BE versus Sq (with the down-regulation of uc.161-, uc.165-, and uc.327-, and the up-regulation of uc.153-, uc.158-, uc.206-, uc.274-, uc.472-, and uc.473-). Analogous BE-specific T-UCR profiles were shared by human and murine lesions. This study is the first demonstration of a role for T-UCRs in the transformation of Barrett's mucosa.
T-UCRs; Barrett's esophagus; Barrett's carcinogenesis; expression signature
MicroRNAs are being exploited for diagnosis, prognosis and monitoring of cancer and other diseases. Their high tissue specificity and critical role in oncogenesis provide new biomarkers for the diagnosis and classification of cancer as well as predicting patients' outcomes. MicroRNAs signatures have been identified for many human tumors, including colorectal cancer (CRC). In most cases, metastatic disease is difficult to predict and to prevent with adequate therapies. The aim of our study was to identify a microRNA signature for metastatic CRC that could predict and differentiate metastatic target organ localization. Normal and cancer tissues of three different groups of CRC patients were analyzed. RNA microarray and TaqMan Array analysis were performed on 66 Italian patients with or without lymph nodes and/or liver recurrences. Data obtained with the two assays were analyzed separately and then intersected to identify a primary CRC metastatic signature. Five differentially expressed microRNAs (hsa-miR-21, -103, -93, -31 and -566) were validated by qRT-PCR on a second group of 16 American metastatic patients. In situ hybridization was performed on the 16 American patients as well as on three distinct commercial tissues microarray (TMA) containing normal adjacent colon, the primary adenocarcinoma, normal and metastatic lymph nodes and liver. Hsa-miRNA-21, -93, and -103 upregulation together with hsa-miR-566 downregulation defined the CRC metastatic signature, while in situ hybridization data identified a lymphonodal invasion profile. We provided the first microRNAs signature that could discriminate between colorectal recurrences to lymph nodes and liver and between colorectal liver metastasis and primary hepatic tumor.
To evaluate the impact of miR-155 on the outcome of adults with cytogenetically normal (CN) acute myeloid leukemia (AML) in the context of other clinical and molecular prognosticators and to gain insight into the leukemogenic role of this microRNA.
Patients and Methods
We evaluated 363 patients with primary CN-AML. miR-155 levels were measured in pretreatment marrow and blood by NanoString nCounter assays that quantified the expression of the encoding gene MIR155HG. All molecular prognosticators were assessed centrally. miR-155–associated gene and microRNA expression profiles were derived using microarrays.
Considering all patients, high miR-155 expression was associated with a lower complete remission (CR) rate (P < .001) and shorter disease-free survival (P = .001) and overall survival (OS; P < .001) after adjusting for age. In multivariable analyses, high miR-155 expression remained an independent predictor for a lower CR rate (P = .007) and shorter OS (P < .001). High miR-155 expressers had approximately 50% reduction in the odds of achieving CR and 60% increase in the risk of death compared with low miR-155 expressers. Although high miR-155 expression was not associated with a distinct microRNA expression profile, it was associated with a gene expression profile enriched for genes involved in cellular mechanisms deregulated in AML (eg, apoptosis, nuclear factor-κB activation, and inflammation), thereby supporting a pivotal and unique role of this microRNA in myeloid leukemogenesis.
miR-155 expression levels are associated with clinical outcome independently of other strong clinical and molecular predictors. The availability of emerging compounds with antagonistic activity to microRNAs in the clinic provides the opportunity for future therapeutic targeting of miR-155 in AML.
Aberrant expression of the secreted protein, acidic, cysteine-rich (osteonectin) (SPARC) gene, which encodes a matricellular protein that participates in normal tissue remodeling, is associated with a variety of diseases including cancer, but the contribution of SPARC to malignant growth remains controversial. We previously reported that SPARC was among the most upregulated genes in cytogenetically normal acute myeloid leukemia (CN-AML) patients with gene-expression profiles predictive of unfavorable outcome, such as mutations in isocitrate dehydrogenase 2 (IDH2-R172) and overexpression of the oncogenes brain and acute leukemia, cytoplasmic (BAALC) and v-ets erythroblastosis virus E26 oncogene homolog (ERG). In contrast, SPARC was downregulated in CN-AML patients harboring mutations in nucleophosmin (NPM1) that are associated with favorable prognosis. Based on these observations, we hypothesized that SPARC expression is clinically relevant in AML. Here, we found that SPARC overexpression is associated with adverse outcome in CN-AML patients and promotes aggressive leukemia growth in murine models of AML. In leukemia cells, SPARC expression was mediated by the SP1/NF-κB transactivation complex. Furthermore, secreted SPARC activated the integrin-linked kinase/AKT (ILK/AKT) pathway, likely via integrin interaction, and subsequent β-catenin signaling, which is involved in leukemia cell self-renewal. Pharmacologic inhibition of the SP1/NF-κB complex resulted in SPARC downregulation and leukemia growth inhibition. Together, our data indicate that evaluation of SPARC expression has prognosticative value and SPARC is a potential therapeutic target for AML.
While microRNA (miRNA) expression is known to be altered in a variety of human malignancies contributing to cancer development and progression, the potential role of miRNA dysregulation in malignant mast cell disease has not been previously explored. The purpose of this study was to investigate the potential contribution of miRNA dysregulation to the biology of canine mast cell tumors (MCTs), a well-established spontaneous model of malignant mast cell disease.
We evaluated the miRNA expression profiles from biologically low-grade and biologically high-grade primary canine MCTs using real-time PCR-based TaqMan Low Density miRNA Arrays and performed real-time PCR to evaluate miR-9 expression in primary canine MCTs, malignant mast cell lines, and normal bone marrow-derived mast cells (BMMCs). Mouse mast cell lines and BMMCs were transduced with empty or pre-miR-9 expressing lentiviral constructs and cell proliferation, caspase 3/7 activity, and invasion were assessed. Transcriptional profiling of cells overexpressing miR-9 was performed using Affymetrix GeneChip Mouse Gene 2.0 ST arrays and real-time PCR was performed to validate changes in mRNA expression.
Our data demonstrate that unique miRNA expression profiles correlate with the biological behavior of primary canine MCTs and that miR-9 expression is increased in biologically high grade canine MCTs and malignant cell lines compared to biologically low grade tumors and normal canine BMMCs. In transformed mouse malignant mast cell lines expressing either wild-type (C57) or activating (P815) KIT mutations and mouse BMMCs, miR-9 overexpression significantly enhanced invasion but had no effect on cell proliferation or apoptosis. Transcriptional profiling of normal mouse BMMCs and P815 cells possessing enforced miR-9 expression demonstrated dysregulation of several genes, including upregulation of CMA1, a protease involved in activation of matrix metalloproteases and extracellular matrix remodeling.
Our findings demonstrate that unique miRNA expression profiles correlate with the biological behavior of canine MCTs. Furthermore, dysregulation of miR-9 is associated with MCT metastasis potentially through the induction of an invasive phenotype, identifying a potentially novel pathway for therapeutic intervention.
Mast cell; microRNA; miR-9
Resveratrol (trans-3,4′,5-trihydroxystilbene) is a natural antioxidant with cardiovascular and cancer preventive properties, that is currently at the stage of pre-clinical studies for human cancer prevention. Beside its known effects on protein coding genes, one possible mechanism for resveratrol protective activities is by modulating the levels of non-coding RNAs. Here, we analyzed the effects of resveratrol on microRNA populations in human SW480 colon cancer cells. We establish that resveratrol treatment decreases the levels of several oncogenic microRNAs targeting genes encoding Dicer1, a cytoplasmic RNase III producing mature microRNAs from their immediate precursors, tumor suppressor factors such as PDCD4 or PTEN, as well as key effectors of the TGFβ signaling pathway, while increasing the levels of miR-663, a tumor-suppressor microRNA targeting TGFβ1 transcripts. We also show that, while upregulating several components of the TGFβ signaling pathway such as TGFβ receptors type I (TGFβR1) and type II (TGFβR2), resveratrol decreases the transcriptional activity of SMADs, the main effectors of the canonical TGFβ pathway. Our results establish that protective properties of resveratrol may arise at least in part from its capability to modify the composition of microRNA populations in cells, and suggest that the manipulation of the levels of key microRNAs, such as miR-663, may help to potentiate the anti-cancer and anti-metastatic effects of resveratrol.
Colon cancer; microRNAs; miR-663; resveratrol; SW480 cells; TGFβ
The regulatory protein nucleolin controls the expression of a subset of miRNAs involved in breast cancer progression and can be targeted to inhibit breast cancer growth in vivo.
Numerous studies have described the altered expression and the causal role of microRNAs (miRNAs) in human cancer. However, to date, efforts to modulate miRNA levels for therapeutic purposes have been challenging to implement. Here we find that nucleolin (NCL), a major nucleolar protein, posttranscriptionally regulates the expression of a specific subset of miRNAs, including miR-21, miR-221, miR-222, and miR-103, that are causally involved in breast cancer initiation, progression, and drug resistance. We also show that NCL is commonly overexpressed in human breast tumors and that its expression correlates with that of NCL-dependent miRNAs. Finally, inhibition of NCL using guanosine-rich aptamers reduces the levels of NCL-dependent miRNAs and their target genes, thus reducing breast cancer cell aggressiveness both in vitro and in vivo. These findings illuminate a path to novel therapeutic approaches based on NCL-targeting aptamers for the modulation of miRNA expression in the treatment of breast cancer.
The success of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) depends on the requirement for BCR-ABL1 kinase activity in CML progenitors. However, CML quiescent HSCs are TKI resistant and represent a BCR-ABL1 kinase–independent disease reservoir. Here we have shown that persistence of leukemic HSCs in BM requires inhibition of the tumor suppressor protein phosphatase 2A (PP2A) and expression — but not activity — of the BCR-ABL1 oncogene. Examination of HSCs from CML patients and healthy individuals revealed that PP2A activity was suppressed in CML compared with normal HSCs. TKI-resistant CML quiescent HSCs showed increased levels of BCR-ABL1, but very low kinase activity. BCR-ABL1 expression, but not kinase function, was required for recruitment of JAK2, activation of a JAK2/β-catenin survival/self-renewal pathway, and inhibition of PP2A. PP2A-activating drugs (PADs) markedly reduced survival and self-renewal of CML quiescent HSCs, but not normal quiescent HSCs, through BCR-ABL1 kinase–independent and PP2A-mediated inhibition of JAK2 and β-catenin. This led to suppression of human leukemic, but not normal, HSC/progenitor survival in BM xenografts and interference with long-term maintenance of BCR-ABL1–positive HSCs in serial transplantation assays. Targeting the JAK2/PP2A/β-catenin network in quiescent HSCs with PADs (e.g., FTY720) has the potential to treat TKI-refractory CML and relieve lifelong patient dependence on TKIs.
Mutations in mitochondrial DNA (mtDNA) have been shown to be an important cause of sensorineural hearing loss (SNHL). In this study, we performed a clinical and genetic analysis of 169 hearing-impaired patients and some of their relatives suffering from idiopathic SNHL, both familial and sporadic. The analysis of four fragments of their mtDNA identified several polymorphisms, the well known pathogenic mutation, A1555G, and some novel mutations in different genes, implying changes in the aminoacidic sequence. A novel sporadic mutation in 12S rRNA (MT-RNR1), not previously reported in the literature, was found in a case of possible aminoglycoside-induced progressive deafness.
mitochondrial DNA; non-syndromic hearing loss; T961G; mitochondrial DNA variants; polymorphisms
MicroRNAs regulate several aspects of tumorigenesis and cancer progression. Most cancer tissues are archived formalin-fixed and paraffin-embedded (FFPE). While microRNAs are a more stable form of RNA thought to withstand FFPE-processing and degradation there is only limited evidence for the latter assumption. We examined whether microRNA profiling can be successfully conducted on FFPE cancer tissues using SOLiD ligation based sequencing. Tissue storage times (2–9 years) appeared to not affect the number of detected microRNAs in FFPE samples compared to matched frozen samples (paired t-test p>0.7). Correlations of microRNA expression values were very high across microRNAs in a given sample (Pearson’s r = 0.71–0.95). Higher variance of expression values among samples was associated with higher correlation coefficients between FFPE and frozen tissues. One of the FFPE samples in this study was degraded for unknown reasons with a peak read length of 17 nucleotides compared to 21 in all other samples. The number of detected microRNAs in this sample was within the range of microRNAs detected in all other samples. Ligation-based microRNA deep sequencing on FFPE cancer tissues is feasible and RNA degradation to the degree observed in our study appears to not affect the number of microRNAs that can be quantified.
The histological definition of Barrett's esophagus (BE) is debated, particularly regarding the phenotype of its metaplastic columnar epithelium. Histologically proven intestinal metaplasia (IM) was the sine qua non condition for a diagnosis of BE but, more recently, non-intestinalized (i.e., cardiac gastric-type; GM) columnar metaplasia has been re-included in the spectrum of Barrett's histology. MicroRNAs modulate cell commitment, and are also reportedly dysregulated in Barrett's carcinogenesis. This study investigates miRNA expression in the histological spectrum of esophageal columnar metaplastic changes, specifically addressing the biological profile of GM vs. IM.
A study was performed to discover microRNA microarray in 30 matching mucosa samples obtained from 10 consecutive BE patients; for each patient, biopsy tissue samples were obtained from squamous, GM and intestinalized epithelium. Microarray findings were further validated by qRT-PCR analysis in another bioptic series of 75 mucosa samples.
MicroRNA profiling consistently disclosed metaplasia-specific microRNA signatures. Six microRNAs were significantly dysregulated across the histological phenotypes considered; five of them (two overexpressed (hsa-miR-192; -miR-215) and three under-expressed (hsa-miR-18a* -miR-203, and -miR-205)) were progressively dysregulated in the phenotypic sequence from squamous to gastric-type, to intestinal-type mucosa samples.
A consistent microRNA expression signature underlies both gastric- and intestinal-type esophageal metaplasia. The pattern of microRNA dysregulation suggests that GM may further progress to IM. The clinico-pathological implications of these molecular profiles prompt further study on the “personalized” cancer risk associated with each of these metaplastic transformations.
Osteosarcoma remains a leading cause of cancer death in adolescents. Treatment paradigms and survival rates have not improved in two decades. Driving the lack of therapeutic inroads, the molecular etiology of osteosarcoma remains elusive. MicroRNAs (miRNAs) have demonstrated far-reaching effects on the cellular biology of development and cancer. Their role in osteosarcomagenesis remains largely unexplored. Here we identify for the first time an miRNA signature reflecting the pathogenesis of osteosarcoma from surgically procured samples from human patients. The signature includes high expression of miR-181a, miR-181b, and miR-181c as well as reduced expression of miR-16, miR-29b, and miR-142-5p. We also demonstrate that miR-181b and miR-29b exhibit restricted expression to distinct cell populations in the tumor tissue. Further, higher expression of miR-27a and miR-181c* in pre-treatment biopsy samples characterized patients who developed clinical metastatic disease. In addition, higher expression of miR-451 and miR-15b in pre-treatment samples correlated with subsequent positive response to chemotherapy. In vitro and in vivo functional validation in osteosarcoma cell lines confirmed the tumor suppressive role of miR-16 and the pro-metastatic role of miR-27a. Furthermore, predicted target genes for miR-16 and miR-27a were confirmed as down-regulated by real-time PCR. Affymetrix array profiling of cDNAs from the osteosarcoma specimens and controls were interrogated according to predicted targets of miR-16, miR142-5p, miR-29b, miR-181a/b, and miR-27a. This analysis revealed positive and negative correlations highlighting pathways of known importance to osteosarcoma, as well as novel genes. Thus, our findings establish a miRNA signature associated with pathogenesis of osteosarcoma as well as critical pre-treatment biomarkers of metastasis and responsiveness to therapy.
osteosarcoma; microRNA; chemotherapy; metastasis-related miRs; gene array
Ultraconserved regions (UCR) are genomic segments of more than 200 base pairs that are evolutionarily conserved among mammalian species. They are thought to have functions as transcriptional enhancers and regulators of alternative splicing. Recently, it was shown that numerous RNAs are transcribed from these regions. These UCR-encoded transcripts (ucRNAs) were found to be expressed in a tissue- and disease-specific manner and may interfere with the function of other RNAs through RNA: RNA interactions. We hypothesized that ucRNAs have unidentified roles in the pathogenesis of human prostate cancer. In a pilot study, we examined ucRNA expression profiles in human prostate tumors.
Using a custom microarray with 962 probesets representing sense and antisense sequences for the 481 human UCRs, we examined ucRNA expression in resected, fresh-frozen human prostate tissues (57 tumors, 7 non-cancerous prostate tissues) and in cultured prostate cancer cells treated with either epigenetic drugs (the hypomethylating agent, 5-Aza 2′deoxycytidine, and the histone deacetylase inhibitor, trichostatin A) or a synthetic androgen, R1881. Expression of selected ucRNAs was also assessed by qRT-PCR and NanoString®-based assays. Because ucRNAs may function as RNAs that target protein-coding genes through direct and inhibitory RNA: RNA interactions, computational analyses were applied to identify candidate ucRNA:mRNA binding pairs.
We observed altered ucRNA expression in prostate cancer (e.g., uc.106+, uc.477+, uc.363 + A, uc.454 + A) and found that these ucRNAs were associated with cancer development, Gleason score, and extraprostatic extension after controlling for false discovery (false discovery rate < 5% for many of the transcripts). We also identified several ucRNAs that were responsive to treatment with either epigenetic drugs or androgen (R1881). For example, experiments with LNCaP human prostate cancer cells showed that uc.287+ is induced by R1881 (P < 0.05) whereas uc.283 + A was up-regulated following treatment with combined 5-Aza 2′deoxycytidine and trichostatin A (P < 0.05). Additional computational analyses predicted RNA loop-loop interactions of 302 different sense and antisense ucRNAs with 1058 different mRNAs, inferring possible functions of ucRNAs via direct interactions with mRNAs.
This first study of ucRNA expression in human prostate cancer indicates an altered transcript expression in the disease.
Ultraconserved region; Gene expression; Prostate cancer
In multiple myeloma (MM), an incurable B-cell neoplasm, mutation or deletion of p53 is rarely detected at diagnosis. Using small-molecule inhibitors of MDM2, we provide evidence that miR-192, 194 and 215, which are down-regulated in a subset of newly diagnosed MMs, can be transcriptionally activated by p53 and then modulate MDM2 expression. Furthermore, ectopic re-expression of these miRNAs in MM cells increases the therapeutic action of MDM2 inhibitors in vitro and in vivo by enhancing their p53-activating effects. In addition, miR-192 and 215 target the IGF pathway, preventing enhanced migration of plasma cells into bone marrow. The results suggest that these miRNAs are positive regulators of p53 and that their down-regulation plays a key role in MM development.
MicroRNAs expression is deregulated in acute myeloid leukemia, but the corresponding functional microRNA-controlled pathways are poorly understood. Integration of mRNA and microRNA expression profiling may allow the identification of functional links between the whole transcriptome and microRNome that are involved in myeloid leukemogenesis.
Therefore, here we integrated microRNA and mRNA expression profiles obtained from 48 newly diagnosed acute myeloid leukemia patients by using two different microarray platforms and performed correlation, gene ontology and network analysis. Experimental validation was also performed in acute myeloid leukemia cell lines using microRNA mimics oligonucleotides and functional assays.
Our analysis identified a strong positive correlation of HOX related genes with miR-10 and miR-20a. Furthermore, we observed a negative correlation between miR-181a and -181b, -155 and -146 expression with that of genes involved in immunity and inflammation (e.g. IRF7 and TLR4) and a positive correlation between miR-23a, miR-26a, miR-128a and miR-145 expression with that of pro-apoptotic genes (e.g., BIM and PTEN). These correlations were confirmed by gene ontology analyses, which evidenced the enrichment of members of the homeobox, immunity and inflammation and apoptosis biologic process, respectively. Furthermore, we validated experimentally the association of miR-145, miR-26a and miR-128a with apoptosis in acute myeloid leukemia.
Our results indicate that by integrating the transcriptome and microRNome in acute myeloid leukemia cells is possible to identify previously unidentified putative functional microRNA-mRNA interactions in acute myeloid leukemia.
microRNA; networks; AML; microarrays