DNMT3A epigenetically regulates key microRNAs involved in epithelial-to-mesenchymal transition in prostate cancer.

Epithelial-to-mesenchymal transition (EMT) is involved in prostate cancer (PCa) metastatic progression, and its plasticity suggests epigenetic implications. Deregulation of DNA methyltransferases (DNMTs) and several microRNAs (miRNAs) plays a relevant role in EMT, but their interplay has not been clarified yet. In this study, we provide evidence that DNMT3A interaction with several miRNAs has a central role in an ex vivo EMT PCa model obtained via exposure of PC3 cells to conditioned media from cancer-associated fibroblasts. The analysis of the alterations of the miRNA profile shows that miR-200 family (miR-200a/200b/429, miR-200c/141), miR-205 and miR-203, known to modulate key EMT factors, are down-regulated and hyper-methylated at their promoters. DNMT3A (mainly isoform a) is recruited onto these miRNA promoters, coupled with the increase of H3K27me3/H3K9me3 and/or the decrease of H3K4me3/H3K36me3. Most interestingly, our results reveal the differential expression of two DNMT3A isoforms (a and b) during ex vivo EMT and a regulatory feedback loop between miR-429 and DNMT3A that can promote and sustain the transition towards a more mesenchymal phenotype. We demonstrate the ability of miR-429 to target DNMT3A 3'UTR and modulate the expression of EMT factors, in particular ZEB1. Survey of the PRAD-TCGA dataset shows that patients expressing an EMT-like signature are indeed characterized by down-regulation of the same miRNAs with a diffused hyper-methylation at miR-200c/141 and miR-200a/200b/429 promoters. Finally, we show that miR-1260a also targets DNMT3A, although it does not seem to be involved in EMT in PCa.

The multi-functionality of UHRF1: epigenome maintenance and preservation of genome integrity.

During S phase, the cooperation between the macromolecular complexes regulating DNA synthesis, epigenetic information maintenance and DNA repair is advantageous for cells, as they can rapidly detect DNA damage and initiate the DNA damage response (DDR). UHRF1 is a fundamental epigenetic regulator; its ability to coordinate DNA methylation and histone code is unique across proteomes of different species. Recently, UHRF1's role in DNA damage repair has been explored and recognized to be as important as its role in maintaining the epigenome. UHRF1 is a sensor for interstrand crosslinks and a determinant for the switch towards homologous recombination in the repair of double-strand breaks; its loss results in enhanced sensitivity to DNA damage. These functions are finely regulated by specific post-translational modifications and are mediated by the SRA domain, which binds to damaged DNA, and the RING domain. Here, we review recent studies on the role of UHRF1 in DDR focusing on how it recognizes DNA damage and cooperates with other proteins in its repair. We then discuss how UHRF1's epigenetic abilities in reading and writing histone modifications, or its interactions with ncRNAs, could interlace with its role in DDR.

Deinococcus radiodurans' SRA-HNH domain containing protein Shp (Dr1533) is involved in faithful genome inheritance maintenance following DNA damage.

BACKGROUND: Deinococcus radiodurans R1 (DR) survives conditions of extreme desiccation, irradiation and exposure to genotoxic chemicals, due to efficient DNA breaks repair, also through Mn2+ protection of DNA repair enzymes. METHODS: Possible annotated domains of the DR1533 locus protein (Shp) were searched by bioinformatic analysis. The gene was cloned and expressed as fusion protein. Band-shift assays of Shp or the SRA and HNH domains were performed on oligonucleotides, genomic DNA from E. coli and DR. shp knock-out mutant was generated by homologous recombination with a kanamycin resistance cassette. RESULTS: DR1533 contains an N-terminal SRA domain and a C-terminal HNH motif (SRA-HNH Protein, Shp). Through its SRA domain, Shp binds double-strand oligonucleotides containing 5mC and 5hmC, but also unmethylated and mismatched cytosines in presence of Mn2+. Shp also binds to Escherichia coli dcm+ genomic DNA, and to cytosine unmethylated DR and E. coli dcm- genomic DNAs, but only in presence of Mn2+. Under these binding conditions, Shp displays DNAse activity through its HNH domain. Shp KO enhanced >100 fold the number of spontaneous mutants, whilst the treatment with DNA double strand break inducing agents enhanced up to 3-log the number of survivors. CONCLUSIONS: The SRA-HNH containing protein Shp binds to and cuts 5mC DNA, and unmethylated DNA in a Mn2+ dependent manner, and might be involved in faithful genome inheritance maintenance following DNA damage. GENERAL SIGNIFICANCE: Our results provide evidence for a potential role of DR Shp protein for genome integrity maintenance, following DNA double strand breaks induced by genotoxic agents.

UHRF1 regulates CDH1 via promoter associated non-coding RNAs in prostate cancer cells.

Non-coding RNAs (ncRNAs) transcribed from the promoter and the downstream region can affect the expression of the corresponding coding genes. It has been shown that sense-directed ncRNAs arising from the promoter region of the E-cadherin gene (CDH1) mediate its repression. Here, we show that an antisense-directed ncRNA (paRCDH1-AS) transcribed from the CDH1 promoter is necessary for its expression. paRCDH1-AS acts as a hooking scaffold by recruiting the epigenetic regulators, UHRF1, DNMT3A, SUV39H1 and SUZ12, involved in CDH1 repression. The binding of epigenetic regulators to paCRDH1-AS, indeed, prevents their localization to the chromatin on CDH1 promoter. Moreover, paRCDH1-AS silencing induces CDH1 repression and a switch of the epigenetic profile on the promoter towards a more closed chromatin. Using bioinformatic and experimental approaches we defined that the promoter of the paRCDH1-AS is shared with the E-cadherin gene, showing a bidirectional promoter activity. We found that UHRF1 controls both CDH1 and paRCDH1-AS by directly binding this bidirectional promoter region. Our study provides evidences, for the first time, that UHRF1 recruitment can be affected by promoter-associated non-coding RNAs, opening new perspective regarding the role of UHRF1 in these complex regulatory networks.

Metabolic syndrome, hepatic steatosis, and cardiovascular risk in children.

OBJECTIVES: Pediatric metabolic syndrome (MetS) is a well-recognized entity; however, there is no consensus on its exact value in predicting long-term cardiovascular (CV) risk. Hepatic steatosis (HS) is another emerging condition associated with pediatric obesity, and data have been reported suggesting a possible role of HS in CV risk linked to MetS. The aim of the present study was to evaluate the usefulness of HS and MetS cluster in predicting CV risk linked to pediatric obesity. METHODS: We studied 803 overweight and obese children (395 girls and 408 boys, mean age 9.4 ± 2.5 y, body mass index z-score 2.2 ± 0.53) with complete clinical and biological assessment. MetS was defined using the modified criteria of the American Heart Association. The diagnosis and severity of the HS was based on ultrasound. To assess CV risk, all patients underwent ultrasonography to measure carotid intima-media thickness (cIMT)-a validated marker of subclinical vascular disease. RESULTS: The overall prevalence of MetS was 13.07%; HS was significantly higher in patients with MetS (40.9 versus 18.5%; P < 0.001; odds ratio, 3.059; 95% confidence interval, 1.98-4.7). Spearman's correlation between HS grade and the number of MetS criteria met by each patient was significant (r = 0.285; P < 0.001). No statistical difference was recorded in cIMT and cIMT z-scores between patients with or without MetS, until inclusion of HS as an additional criterion for the diagnosis of MetS. In this case, there was a significant difference in cIMT z-scores between the two groups. In multiple linear regression analysis, the cIMT z-score value was better predicted with HS grade and the MetS cluster (adjusted R2 = 2.6%; P = 0.002) than when using the MetS cluster only. CONCLUSIONS: HS could be used as additional criterion in detecting pediatric MetS phenotype at higher risk for long-term CV morbidity.

In vitro hydroquinone-induced instauration of histone bivalent mark on human retroelements (LINE-1) in HL60 cells.

Benzene is extensively used in industry despite its leukemogenic activity, representing a significant occupational hazard. We investigated if long-term treatment with low-doses hydroquinone (HQ), a benzene metabolite, might be sufficient to alter in vitro the epigenetic signature underlining LINE-1 sequences, a poorly explored step in health risks associated with benzene exposure. In HL-60 cell line, exploring the epigenetic events occurring in chromatin, we found the transient instauration of the distinctive signature combining the repressive H3Lys27 tri-methylation mark and the activating H3Lys4 tri-methylation mark (H3K27me3/H3K4me3), indicating a tendency toward a poised chromatin conformation. These alterations are lost in time after short-term treatments, while the long-term setting, performed using a concentration within the levels of total HQ in peripheral blood of benzene-exposed workers, showed a gradual increase in H3K4me3. We observed the absence of statistically significant variations in DNA methylation and expression levels of LINE-1, despite a decrease in protein levels of UHRF1, DNA methyl-transferases and histone methyl-transferases. In conclusion, in vitro treatment with low-dose HQ determined the instauration of a reversible poised state of chromatin in LINE-1 sequences, suggesting that prolonged exposure could cause persistent epigenetic alterations.

The BH3-mimetic obatoclax reduces HIF-1α levels and HIF-1 transcriptional activity and sensitizes hypoxic colon adenocarcinoma cells to 5-fluorouracil.

Activation of hypoxia-inducible factor (HIF)-1 is a feature of hypoxic solid tumors that has been associated with drug resistance, mainly due to disruption of Bcl-2 family dynamics. Resetting the balance in favor of proapoptotic family members is an attractive therapeutic goal that has been pursued by developing BH3-mimetic compounds. In the present study we evaluated the response of human colon adenocarcinoma cells to the BH3-mimetic obatoclax (OBX), in terms of growth arrest, apoptosis and autophagy, in the presence or absence of HIF-1α-stabilizing conditions; its possible effect on HIF-1α expression and HIF-1 activity; and the possibility to improve the response of colon cancer cells to cytotoxic chemotherapeutics by combining them with OBX. Colon cancer cell response to the BH3-mimetic was unmodified by HIF-1 activation and OBX induced a decrease in HIF-1α protein levels and HIF-1 transcriptional activity, probably by decreasing HIF-1α synthesis and facilitating a VHL-independent proteasomal degradation pathway. Finally, a chemosensitizing effect of OBX with respect to 5-fluorouracil or oxaliplatin treatment was observed, highlighting the possibility that patients with hypoxic colon tumors might benefit from combined regimens including OBX.

Giant neglected squamous cell carcinoma of the skin.

Nonmelanoma skin cancers (NMSCs) are the most common type of skin tumor, representing about one-third of all malignancies diagnosed worldwide each year. Cutaneous squamous cell carcinoma (cSCC) is the second most common form of NMSCs and the risk of cSCC invasiveness should be assessed on the basis of tumor size, anatomical location, and histological subtype. Although most cSCCs are early diagnosed and successfully treated, in a small percentage of patients with giant cSCC (maximum diameter >5 cm), metastases may occur; treatment options are limited and not really effective. We report the case of a giant metastatic cSCC that had been neglected for more than 20 years. Radiotherapy or surgery were not feasible and polichemotherapy (cisplatin, 5-fluorouracil and paclitaxel) was not effective. Therefore, the patient was treated with palliative electrochemotherapy (ECT) achieving a partial reduction of cutaneous metastasis and pain relief but unfortunately the patient died 3 months after the second ECT treatment.

Synthesis and photodynamic activity of a panel of BODIPY dyes.

Eight BODIPY dyes were synthesized and used as photosensitizers (PSs) on the human colon carcinoma cell line HCT116. In this panel of molecules, the structure varies in the substituents on pyrrole 2, 6 positions and on the phenyl ring at the indacene 8 position. For these compounds relevant physico-chemical parameters, such as singlet oxygen production, fluorescent quantum yield, absorbance profile and a relative rank of lipophilicity were determined. Our results indicate that some of these novel PSs are very effective in reducing the growth/viability of HCT116 cells when irradiated with a green LED source, whereas they are practically devoid of activity in the dark, up to 5 µM. To evaluate whether cell death is induced under these conditions, flow cytometric analysis of the percentage of apoptotic and autophagic cells was performed on four molecules, chosen for their efficacy/structural characteristics. Our data indicate that phototoxicity likely occurs mainly through apoptotic cell death, whereas autophagy seems to play a minor role in determining cell fate. Furthermore, the relationship between singlet oxygen generation and the PS efficacy is confirmed, thus underscoring the importance of the heavy-atom effect and of the presence of an aryl substituent at dipyrromethene 8 (meso) position. Among the PSs here described, the most efficient BODIPY was successfully tested on three other human cancer cell lines of different tissue origin, MCF7 (breast), A2780 and A2780/CP8 (ovary, sensitive and resistant to cisplatin, respectively), yielding IC(50) values comparable to those obtained on HCT116.

Electrochemotherapy in the treatment of Kaposi sarcoma cutaneous lesions: a two-center prospective phase II trial.

BACKGROUND: Electrochemotherapy (ECT) is an emerging treatment for cutaneous lesions of different tumor types. The combination of chemotherapy and electroporation enhances drug uptake into tumoral cells. However, its role in the treatment of Kaposi sarcoma (KS) has not yet been well defined, and to date, literature reports are scarce. We prospectively evaluated clinical activity and safety of ECT in KS patients. METHODS: Twenty-three patients with histologically confirmed unresectable KS, not treatable by radiotherapy or intralesional vincristine therapy, were enrolled onto the study according to the European Standard Operating Procedures of Electrochemotherapy (ESOPE) guidelines and treated with a pulse generator. RESULTS: A response to the first ECT session was obtained in all patients, with a complete response (CR) in 14 (60.9%) of 23 patients. A second ECT was performed in 5 (21.7%) and a third in 2, with a median interval between two sessions of 5.1 (range 2.5-25.5) months. Overall, a total of 15 patients (65%) experienced a CR. After a median follow-up of 1.5 years (range 2 months to 4.2 years), 16 patients maintained the response, 4 after repeated courses. Sustained local control of treated lesions was present in 20 of 23 patients. The overall survival rate was 74.4% at 2 years. CONCLUSIONS: ECT represents an additional therapeutic tool for the management of KS cutaneous lesions, characterized by a definite clinical activity and long-lasting remissions. The absence of systemic side effects and the low impact on the immune system also make this treatment suitable for elderly people, even with repeated courses.

The radiosensitizing effect of Ku70/80 knockdown in MCF10A cells irradiated with X-rays and p(66)+Be(40) neutrons.

BACKGROUND: A better understanding of the underlying mechanisms of DNA repair after low- and high-LET radiations represents a research priority aimed at improving the outcome of clinical radiotherapy. To date however, our knowledge regarding the importance of DNA DSB repair proteins and mechanisms in the response of human cells to high-LET radiation, is far from being complete. METHODS: We investigated the radiosensitizing effect after interfering with the DNA repair capacity in a human mammary epithelial cell line (MCF10A) by lentiviral-mediated RNA interference (RNAi) of the Ku70 protein, a key-element of the nonhomologous end-joining (NHEJ) pathway. Following irradiation of control and Ku-deficient cell lines with either 6 MV X-rays or p(66)+Be(40) neutrons, cellular radiosensitivity testing was performed using a crystal violet cell proliferation assay. Chromosomal radiosensitivity was evaluated using the micronucleus (MN) assay. RESULTS: RNAi of Ku70 caused downregulation of both the Ku70 and the Ku80 proteins. This downregulation sensitized cells to both X-rays and neutrons. Comparable dose modifying factors (DMFs) for X-rays and neutrons of 1.62 and 1.52 respectively were obtained with the cell proliferation assay, which points to the similar involvement of the Ku heterodimer in the cellular response to both types of radiation beams. After using the MN assay to evaluate chromosomal radiosensitivity, the obtained DMFs for X-ray doses of 2 and 4 Gy were 2.95 and 2.66 respectively. After neutron irradiation, the DMFs for doses of 1 and 2 Gy were 3.36 and 2.82 respectively. The fact that DMFs are in the same range for X-rays and neutrons confirms a similar importance of the NHEJ pathway and the Ku heterodimer for repairing DNA damage induced by both X-rays and p(66)+Be(40) neutrons. CONCLUSIONS: Interfering with the NHEJ pathway enhanced the radiosensitivity of human MCF10A cells to low-LET X-rays and high-LET neutrons, pointing to the importance of the Ku heterodimer for repairing damage induced by both types of radiation. Further research using other high-LET radiation sources is however needed to unravel the involvement of DNA double strand break repair pathways and proteins in the cellular response of human cells to high-LET radiation.

Lentivirus-mediated RNA interference of Ku70 to enhance radiosensitivity of human mammary epithelial cells.

PURPOSE: To investigate the radiosensitising effect of Ku autoantigen 70 (Ku70) and Ku autoantigen 80 (Ku80) knockdown by lentivirus-mediated RNA interference (RNAi) in the MCF10A immortalised human mammary epithelial cell line. MATERIALS AND METHODS: MCF10A cells were infected with lentiviral vectors for RNAi of Ku70. The Ku70-knockdown cell line (Ku70i) and a mock-infected control cell line (LVTHM) were used to perform radiation experiments. For the in vitro Micronucleus (MN) assay, both cell lines were irradiated with doses of 2 and 4 Gy (60)Co gamma-rays. For cell survival experiments, doses ranging between 0 and 8 Gy were used. RESULTS: Western blot analysis showed that the Ku70 lentiviral vector was effective in silencing the expression of both Ku70 and Ku80. A significantly higher radiation-induced MN yield was obtained in the Ku70i cell line compared to the control LVTHM cell line. RNAi of Ku70 also resulted in a lower survival yield after irradiation compared to the control cell line. Analysis of cell death mechanisms showed that MCF10A cells (Ku70i and LVTHM) do not undergo apoptosis, but undergo post-irradiation cellular senescence. CONCLUSION: RNAi of Ku70 resulted in increased chromosomal and cellular radiosensitivity in the MCF10A human mammary cell line after irradiation with (60)Co gamma-rays. These results further strengthen the role of the Ku protein in correct DNA double strand break (DSB) repair.

Management of skin ulcers in a patient with mycosis fungoides.

We present a patient with a cutaneous T-cell lymphoma/mycosis fungoides (CTCL/MF) followed for more than 10 years. After several different aggressive treatments to control progression of CTCL/MF, the patient developed several ulcerated tumors on the abdomen and limbs. Specific systemic antibiotic therapy failed to treat skin infection. While treating the stage III CTCL with polychemotherapy, we used an active colloidal hydrogel topically to manage wound healing and to treat and prevent potential sources of sepsis. After 11 weeks of treatment we observed complete cicatrization of ulcerated tumors. We reported on this case to describe the importance of a correct management of skin ulcers in immunosuppressed patients in order to avoid possible systemic spread of infection which represents the major cause of death in these patients.

Length effect in word naming in reading: role of reading experience and reading deficit in italian readers.

Vocal reaction times (RTs) in naming 3- to 8-letter words were measured in proficient and dyslexic readers (Study 1). In proficient readers, RTs were independent of word length up to 5-letter words, indicating parallel processing. In the 5- to 8-letter range, RTs increased linearly, indicating sequential processing. Reading experience was associated with both faster discrimination of individual elements and parallel processing of increasingly large word parts. In dyslexics, RTs increased linearly with increasing length indicating reliance on sequential decoding. Individual analysis indicated 2 profiles of RTs (Types A and B). In Study 2, the distinction between A and B dyslexics was not associated with the use of different reading procedures. However, a more marked speed deficit characterized Type B dyslexics.