miR-32 promotes MYC-driven prostate cancer

miR-32 is an androgen receptor (AR)-regulated microRNA, expression of which is increased in castration-resistant prostate cancer (PC). We have previously shown that overexpression of miR-32 in the prostate of transgenic mice potentiates proliferation in prostate epithelium. Here, we set out to determine whether increased expression of miR-32 influences growth or phenotype in prostate adenocarcinoma in vivo. We studied transgenic mice expressing MYC oncogene (hiMYC mice) to induce tumorigenesis in the mouse prostate and discovered that transgenic overexpression of miR-32 resulted in increased tumor burden as well as a more aggressive tumor phenotype in this model. Elevated expression of miR-32 increased proliferation as assessed by Ki-67 immunohistochemistry, increased nuclear density, and higher mitotic index in the tumors. By gene expression analysis of the tumorous prostate tissue, we confirmed earlier findings that miR-32 expression regulates prostate secretome by modulating expression levels of several PC-related target genes such as Spink1, Spink5, and Msmb. Further, we identified Pdk4 as a tumor-associated miR-32 target in the mouse prostate. Expression analysis of PDK4 in human PC reveals an inverse correlation with miR-32 expression and Gleason score, a decrease in castration-resistant and metastatic tumors compared to untreated primary PC, and an association of low PDK4 expression with a shorter recurrence-free survival of patients. Although decreased PDK4 expression induces the higher metabolic activity of PC cells, induced expression of PDK4 reduces both mitotic respiration and glycolysis rates as well as inhibits cell growth. In conclusion, we show that miR-32 promotes MYC-induced prostate adenocarcinoma and identifies PDK4 as a PC-relevant metabolic target of miR-32-3p.</p

miR-32 promotes MYC-driven prostate cancer

miR-32 is an androgen receptor (AR)-regulated microRNA, expression of which is increased in castration-resistant prostate cancer (PC). We have previously shown that overexpression of miR-32 in the prostate of transgenic mice potentiates proliferation in prostate epithelium. Here, we set out to determine whether increased expression of miR-32 influences growth or phenotype in prostate adenocarcinoma in vivo. We studied transgenic mice expressing MYC oncogene (hiMYC mice) to induce tumorigenesis in the mouse prostate and discovered that transgenic overexpression of miR-32 resulted in increased tumor burden as well as a more aggressive tumor phenotype in this model. Elevated expression of miR-32 increased proliferation as assessed by Ki-67 immunohistochemistry, increased nuclear density, and higher mitotic index in the tumors. By gene expression analysis of the tumorous prostate tissue, we confirmed earlier findings that miR-32 expression regulates prostate secretome by modulating expression levels of several PC-related target genes such as Spink1, Spink5, and Msmb. Further, we identified Pdk4 as a tumor-associated miR-32 target in the mouse prostate. Expression analysis of PDK4 in human PC reveals an inverse correlation with miR-32 expression and Gleason score, a decrease in castration-resistant and metastatic tumors compared to untreated primary PC, and an association of low PDK4 expression with a shorter recurrence-free survival of patients. Although decreased PDK4 expression induces the higher metabolic activity of PC cells, induced expression of PDK4 reduces both mitotic respiration and glycolysis rates as well as inhibits cell growth. In conclusion, we show that miR-32 promotes MYC-induced prostate adenocarcinoma and identifies PDK4 as a PC-relevant metabolic target of miR-32-3p.publishedVersionPeer reviewe

Circulating microRNAs found dysregulated in ex-exposed asbestos workers and pleural mesothelioma patients as potential new biomarkers

Malignant pleural mesothelioma (MPM), a fatal cancer, is an occupational disease mostly affecting workers ex-exposed to asbestos fibers. The asbestos, a cancerogenic mineral of different chemical composition, was widely employed in western Countries in industrial manufactures of different types. MPM may arise after a long latency period, up to five decades. MPM is resistant to conventional chemo- and radio-therapies. Altogether, these data indicate that the identification of new and specific markers are of a paramount importance for an early diagnosis and treatment of MPM. In recent years, microRNAs expression was found dysregulated in patients, both in cancer cells and sera, affected by tumors of different histotypes, including MPM. Cell and circulanting microRNAs, found to be dysregulated in this neoplasia, were proposed as new biomarkers. It has been reported that circulating microRNAs are stable in biological fluids and could be employed as potential MPM biomarkers. In this investigation, circulating microRNAs (miR) from serum samples of MPM patients and workers ex-exposed to asbestos fibers (WEA) and healthy subjects (HS) were comparatively analyzed by microarray and RT-qPCR technologies. Our results allowed (i) to select MiR-3665, an endogenous stable microRNA, as the internal control to quantify in our analyses circulating miRNAs; to detect (ii) miR-197-3p, miR-1281 and miR 32-3p up-regulated in MPM compared to HS; (iii) miR-197-3p and miR-32-3p up-regulated in MPM compared to WEA; (iv) miR-1281 up-regulated in both MPM and WEA compared to HS. In conclusion, three circulating up-regulated microRNAs, i.e. miR-197-3p, miR-1281 and miR-32-3p are proposed as potential new MPM biomarker

Microrna regulation of human choline kinase alpha gene expression and function in cancer cell lines

Choline kinase alpha (CHKA), the first enzyme of Kennedy pathway, has noncatalytic function in tumour onset and progression. Overexpression of chka is a clinical feature in malignant cells and cancerous tissues. microRNAs (miRNAs) are efficient posttranscriptional regulators of gene expression. To date, the regulation of chka gene expression by miRNAs has never been reported. The objective of this work was to exploit the gene regulatory capabilities of chka-targeting miRNAs to downregulate chka expression in breast (MCF7), cervical (HeLa) and liver (HepG2) cancer cells and study the effects of the downregulated CHKA protein levels on cellular processes. miRNAs exhibiting increased potential of interacting with the 3’UTR of chka gene were predicted using online available bioinformatic tools, shortlisted based on predefined selection criteria and the shortlisted miRNA candidates were tested in-vitro to study the miRNA:mRNA interaction in cancer cells. miR-32- 5p, miR-367-3p and miR-876-5p each exhibited strong in silico interaction with chka mRNA, releasing free energy (MFE) lower than -1.00 kcal/mol and fulfilling other predefined criteria for determining strong miRNA:mRNA interactions. Binding of the selected three miRNAs with respective seed sites on 3’UTR of chka mRNA was experimentally validated in MCF7, HeLa and HepG2 cells by luciferase assay. Effects of miRNA:mRNA interaction on chka expression at mRNA and protein levels were examined by qRTPCR and western blot. Cellular functions impacted by miRNA mediated differential chka expression were studied by cell apoptosis assay, cell cycle assay and wound healing assay. Compared to negative control, chka expression levels, in HeLa, HepG2 and MCF7, as a result of transfection with miR-32-5p, miR-367-3p and miR-876-5p were 0.47-fold, 0.62-fold, and 0.76-fold, respectively in MCF7; 0.32- fold, 0.38-fold, and 0.63-fold, respectively in HeLa; 0.44-fold, 0.49-fold and 0.51-fold, respectively in HepG2 indicating maximum reduction was inflicted by miR-32-5p. Similar effect was observed when miR-32-5p was combined with miR-876-5p, which resulted in 0.33-fold chka downregulation in MCF7 cells. Correspondingly, transfection of miR-32-5p also produced the strongest suppression of CHKA protein levels in MCF7 (0.20-fold) and HeLa (0.46-fold) compared to other miRNAs tested. The specificity of miRNA mimics towards chka was verified by the firefly luciferase reporter assay and co-treatment with miRNA specific inhibitors, which led to reversal of the decreased chka levels produced by the miRNAs. The three miRNAss and the pair of miR-32-5p+miR-367-3p each initiated ~50% cells to undergo apoptosis in HeLa and MCF7 cells. Maximum (77% of cell population) cell cycle arrest at the G0/G1 phase was prompted by miR-367-3p in MCF7. Wound repair function plummeted with <50% wound area healed even after 96 hrs in MCF7, HeLa and HepG2 treated with miR-32-5p alone and in combination with miR-367-3p. The data collected in this study showed an inverse relationship between the three miRNA candidates and chka expression level, thus, proving the potential of miR-32-5p, miR-367-3p and miR-876- 5p as biomarkers for early cancer prognosis and anti-cancer remedies in cancer types with over expressed chka as a clinical observation

Computational identification of Penaeus monodon microRNA genes and their targets

MicroRNAs (miRNAs) are a distinct class of small non-coding RNAs, ~22 nt long, found in a wide variety of organisms.They play important regulatory roles by silencing gene activities at the post-transcriptional level. In this work, we developeda computational workflow to identify conserved miRNA genes in the 10,536 unique Penaeus monodon expressed sequencetags (ESTs). After removing all simple repeats and coding regions in the ESTs, the workflow uses both the conservationof miRNA sequences and several filters obtained from pre-miRNA secondary structure properties to identify conservedmiRNAs. Finally, we discovered six potential conserved miRNA genes such as mir-4152, mir-466k, miR-32*, lin-4, mir-1346 andmir-4310

The role of 8q amplification and microRNAs in prostate cancer

Eturauhassyöpä on esiintyvyydeltään miesten yleisin syöpä Suomessa ja muissa länsimaissa. Vaikka eturauhassyöpä on yleensä hitaasti etenevä tauti ja sen ennuste on hyvä, osa syövistä on aggressiivisia. Pitkälle edenneitä syöpiä hoidetaan hormonihoidolla, joka aluksi tehoaa hyvin. Syöpä kuitenkin muuttuu jossain vaiheessa hormonihoidolle resistentiksi kasvaimeksi (kastraatioresistentti eturauhassyöpä), johon ei ole enää parantavaa hoitoa. Intensiivisestä tutkimuksesta huolimatta eturauhassyövän molekylaariset mekanismit ovat vielä osittain tuntematta. Androgeenireseptorin (AR) tiedetään vaikuttavan kastraatioresistentin syövän syntyyn, mutta muiden geenien merkitystä ei vielä tunneta. Lisäksi eturauhassyövän yleisimmät kromosomimuutokset on kartoitettu, mutta muutosten takana olevien geenien löytäminen on vielä kesken. Yksi yleisimmistä kromosomaalisista muutoksista, joka löytyy kastraatioresistentistä syövästä, on kromosomi 8 pitkän käsivarren monistuma, jonka on osoitettu olevan yhteydessä potilaiden huonoon ennusteeseen eturauhassyöpäleikkauksen jälkeen. Tässä tutkimuksessa tutkittiin toiminnallisin kokein neljää mahdollista kohdegeeniä, joista TCEB1:n osoitettiin edistävän syöpäsolujen invaasiota ja alustasta riippumatonta kasvua. Tämän lisäksi TCEB1:n yli-ilmentäminen hiiren fibroblastisolulinjassa lisäsi solujen kasvua. Tulosten perusteella näyttää siltä, että TCEB1 on mahdollinen kohdegeeni 8q21 alueen monistumalle. Lisäksi tutkittiin mikro-RNA:iden (miRNA) ilmentymismuutoksia kahdesta eri kliinisten näytteiden sarjasta. miRNA:t ovat lyhyitä ei-koodaavia RNA:ita, jotka negatiivisesti säätelevät geenien ilmentymistä. Tutkimuksessa löydettiin 25:n miRNA:n paneeli, jonka ilmentymismuutokset pystyivät erottamaan aggressiiviset kasvaimet ei-aggressiivisista. Tämän lisäksi kahden miRNA:n, miR-32:n ja miR-148a:n, osoitettiin olevan androgeenien säätelemiä ja yli-ilmentyneitä kastraatioresistentissä syövässä. Niiden ilmentäminen eturauhassyöpäsolulinjassa lisäsi solujen kasvua, miR-32 vähentäen solukuolleisuutta. Androgeenit lisäävät molempien miRNA:iden ilmentymistä, ja AR:n sitoutumiskohta löytyy läheltä molempien miRNA:iden genomista sijaintia. miR-32:n kohdegeeniksi löydettiin BTG2 ja miR-148a:n PIK3IP1. BTG2 proteiinin ilmentyminen vähenee huomattavasti kastraatioresistentissä syövässä. Lisäksi BTG2 proteiinin häviämisen osoitettiin olevan yhteydessä lyhyempään leikkauksen jälkeiseen progressiovapaaseen aikaan. Erityisesti miR-32:n, ja sen kohdegeenin BTG2:n, roolin selvittäminen kastraatioresistentin syövän synnyssä antaa aihetta lisätutkimuksille. Lisäksi tässä tutkimuksessa osoitettiin, että miRNA:iden ilmentymisprofiilin avulla voidaan ennustaa potilaiden leikkauksen jälkeistä prognoosia. Lisää tutkimuksia kuitenkin vaaditaan, jotta miRNA:ita voitaisiin käyttää eturauhassyövän prognostisena indikaattorina.Despite extensive research in recent years, the molecular mechanisms underlying prostate cancer initiation and progression are not fully understood. Key chromosomal aberrations have been identified, yet many of the target genes remain elusive. Castration-resistant prostate cancer (CRPC) is a lethal disease that emerges after hormonal therapy. So far, the only gene known to be involved in the formation of CRPC is the androgen receptor (AR). A gain of the long arm of chromosome 8 is one of the most common findings in CRPC; in fact, 60-90% of these tumors harbor this particular gain. In addition, 8q gain is associated with poor prognosis in prostatectomy-treated patients. Several minimal regions have been identified, suggesting the existence of multiple target genes. Four of the putative target genes (EIF3H, TCEB1, KIAA0196 and RAD21) within the 8q gain region have been functionally evaluated. Of these, TCEB1, located at 8q21, was shown to promote invasion and to affect the anchorage-independent growth of prostate cancer cells. Furthermore, TCEB1 overexpression enhanced the growth of murine fibroblasts. These data indicate that TCEB1 is a putative target gene for gain of the minimal 8q21 region. microRNAs (miRNA) are short, non-coding RNAs that negatively regulate gene expression and can function as tumor suppressor miRs or oncomiRs. To address whether miRNAs are involved in prostate cancer progression, their expression was investigated in two different clinical datasets (102 samples and 54 samples). A panel of 25 miRNAs was able to distinguish aggressive from less aggressive tumors. Androgen-regulated miRNAs involved in CRPC were identified by combining information on androgen receptor binding sites (ARBS) and CRPC miRNA expression profiles. Twenty-eight miRNAs were deregulated in CRPC and contained ARBS. Exogenous overexpression of miR-32 and miR-148a enhanced the growth of an androgen-responsive cell line; miR-32 accomplished this by reducing apoptosis. The expression of these two miRNAs was demonstrated to be up-regulated by androgens and increased in CRPC. In addition, ARBS were detected in close proximity to these miRNAs. BTG2 and PIK3IP1 were identified as target genes for miR-32 and miR-148a, respectively. BTG2 expression was markedly decreased in CRPC, and the loss of BTG2 expression was associated with shorter progression-free survival in prostatectomy-treated patients. In conclusion, TCEB1, miR-148a and miR-32 were demonstrated to possess oncogenic functions in prostate cancer. They are all overexpressed in CRPC and, in initial cell-based studies, affected invasion, proliferation and apoptosis. miR-32 and miR-148a were determined to be androgen-regulated. In addition, miRNA expression profiling was effective in predicting the prognosis of prostatectomy-treated patients. However, additional studies are necessary to evaluate the role of miRNAs as prognostic indicators in prostate cancer

MicroRNAs and epithelial-mesenchymal transition in prostate cancer.

Prostate cancer (PCa) is a leading cause of male cancer-related deaths. A significant fraction of prostate tumors are very aggressive, often metastasizing to bone, causing significant morbidity and mortality. Also, PCa is associated with high rates of recurrence, often attributed to the existence of cancer stem cells. Epithelial-mesenchymal transition (EMT), a process characterized by decreased expression of epithelial genes and increased expression of mesenchymal genes, plays a critical role in tumor invasion, metastasis and recurrence. In PCa, EMT has been implicated particularly in the context of metastatic disease and microRNAs have emerged as critical post-transcriptional regulators of PCa EMT. In this review, we summarize the role of miRNAs in PCa EMT that play a role in progression, metastasis and recurrence. Studies till date suggest that microRNAs mediate efficient and reversible control of PCa EMT via multiple mechanisms including either by (i) directly repressing single or multiple EMT-TFs or regulating cytoskeletal components (epithelial/mesenchymal genes) or (ii) regulating key signaling pathways involved in EMT. Oncogenic microRNAs often act as EMT promoters by repressing epithelial characteristics and tumor suppressive miRNAs act by inhibiting mesenchymal progression. Further, EMT is mechanistically linked to stem cell signatures in PCa and several miRNAs implicated in EMT have been reported to influence PCa stem cells. Loss of EMT-inhibiting miRNAs and/or gain of EMT promoting miRNAs lead to induction of PCa EMT, leading to tumor progression, metastasis and recurrence. Restoring expression of tumor suppressive miRNAs and inhibiting oncogenic miRNAs represent potential therapeutic opportunities to prevent disease metastasis and recurrence

Triggered star formation and Young Stellar Population in Bright-Rimmed Cloud SFO 38

We have investigated the young stellar population in and around SFO 38, one of the massive globules located in the northern part of the Galactic HII region IC 1396, using the Spitzer IRAC and MIPS observations (3.6 to 24 micron) and followed up with ground based optical photometric and spectroscopic observations. Based on the IRAC and MIPS colors and H-alpha emission we identify ~45 Young Stellar Objects (Classes 0/I/II) and 13 probable Pre Main Sequence candidates. We derive the spectral types (mostly K- and M-type stars), effective temperatures and individual extinction of the relatively bright and optically visible Class II objects. Based on optical photometry and theoretical isochrones, we estimate the spread in stellar ages to be between 1--8 Myr with a median age of 3 Myr and a mass distribution of 0.3--2.2 Msun with a median value around 0.5 Msun. Using the width of the H-alpha emission line measured at 10% peak intensity, we derive the mass accretion rates of individual objects to be between 10^{-10} to 10^{-8} Msun/yr. From the continuum-subtracted H-alpha line image, we find that the H-alpha emission of the globule is not spatially symmetric with respect to the O type ionizing star HD 206267. We clearly detect an enhanced concentration of YSOs closer to the southern rim of SFO~38 and identify an evolutionary sequence of YSOs from the rim to the dense core of the cloud, with most of the Class II objects located at the bright rim. The YSOs appear to be aligned along two different directions towards the O6.5V type star HD 206267 and the B0V type star HD 206773. This is consistent with the Radiation Driven Implosion (RDI) model for triggered star formation. (Abridged)Comment: Accepted for publication in Ap

miRNAs link metabolic reprogramming to oncogenesis

The most profound biochemical phenotype of cancer cells is their ability to metabolize glucose to lactate, even under aerobic conditions. This alternative metabolic circuitry is sufficient to support the biosynthetic and energy requirements for cancer cell proliferation and metastasis. Alterations in oncogenes and tumor suppressor genes are involved in the metabolic switch of cancer cells to aerobic glycolysis, increased glutaminolysis and fatty acid biosynthesis. MiRNAs mediate fine-tuning of genes involved directly or indirectly in cancer metabolism. In this review, we discuss the regulatory role of miRNAs on enzymes, signaling pathways and transcription factors involved in glucose and lipid metabolism. We further consider the therapeutic potential of metabolism-related miRNAs in cancer

Serum microRNA in patients undergoing atrial fibrillation ablation.

MicroRNAs mediate posttranscriptional gene regulation. The aim of the study was to find a microRNA predictor of successful atrial fibrillation (AF) ablation. A total of 109 patients undergoing first-time AF ablation were included. Nineteen patients were selected to undergo serum microRNA sequencing (study group). The sequencing data were used to select several microRNAs that correlated with 12-month recurrences after AF ablation. Those microRNAs were validated by digital droplet PCR in samples from remaining 90 patients. All patients underwent pulmonary vein isolation (RF ablation, contact force catheter, electroanatomical system). The endpoint of the study was the 12-month AF recurrence rate; the overall recurrence rate was 42.5%. In total, levels of 34 miRNAs were significantly different in sera from patients with AF recurrence compared to patients without AF recurrence. Six microRNAs (miR-183-5p, miR-182-5p, miR-32-5p, miR-107, miR-574-3p, and miR-144-3p) were validated in the whole group. Data from the validation group did not confirm the observations from the study group, as no significant differences were found between miRNAs serum levels in patients with and without recurrences 12 months after AF ablation