Publications by authors named "Francesca Lovat"

44 Publications

Loss of expression of both miR-15/16 loci in CML transition to blast crisis.

Proc Natl Acad Sci U S A 2021 Mar;118(11)

Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH 43210;

Despite advances that have improved the treatment of chronic myeloid leukemia (CML) patients in chronic phase, the mechanisms of the transition from chronic phase CML to blast crisis (BC) are not fully understood. Considering the key role of miR-15/16 loci in the pathogenesis of myeloid and lymphocytic leukemia, here we aimed to correlate the expression of miR-15a/16 and miR-15b/16 to progression of CML from chronic phase to BC. We analyzed the expression of the two miR-15/16 clusters in 17 CML patients in chronic phase and 22 patients in BC and in 11 paired chronic phase and BC CML patients. BC CMLs show a significant reduction of the expression of miR-15a/-15b/16 compared to CMLs in chronic phase. Moreover, BC CMLs showed an overexpression of miR-15/16 direct targets such as Bmi-1, ROR1, and Bcl-2 compared to CMLs in chronic phase. This study highlights the loss of both miR-15/16 clusters as a potential oncogenic driver in the transition from chronic phase to BC in CML patients.
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http://dx.doi.org/10.1073/pnas.2101566118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980455PMC
March 2021

Combined loss of function of two different loci of miR-15/16 drives the pathogenesis of acute myeloid leukemia.

Proc Natl Acad Sci U S A 2020 06 18;117(22):12332-12340. Epub 2020 May 18.

Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH 43210;

Double knockout of the two miR-15/16 loci in mouse resulted in the development of acute myeloid leukemia (AML). This result suggested that, at least, a fraction of human AMLs could be due to a similar mechanism. We analyzed the role of the two miR-15/16 clusters in 93 myelodysplastic syndrome (MDS) patients divided in three subgroups: patients with MDS, patients with MDS before transforming into AML (MDS-T), and patients with AML evolving from MDS (MDS-AML). Then, we tested 139 AML cases and 14 different AML cell lines by assessing microRNA (miRNA) expression, target protein expression, genetic loss, and silencing. MDS-T and MDS-AML patients show a reduction of the expression of miR-15a/-15b/-16 compared to MDS patients. Each miRNA can significantly predict MDS and MDS-T groups. Then, 79% of primary AMLs show a reduced expression of miR-15a and/or miR-15b. The expression of miR-15a/-15b/-16 significantly stratified AML patients in two prognostic classes. Furthermore, 40% of AML cell lines showed a combined loss of the expression of miR-15a/-15b and overexpression of their direct/indirect targets. As potential mechanisms involved in the silencing of the two miR-15/16 loci, we identified a genetic loss of miR-15a and miR-15b and silencing of these two loci by methylation. We identified a potential driver oncogenic role in the loss of expression of both miR-15/16 clusters in the progression of MDS into AML and in AML pathogenesis. The stratification of AML patients, based on miR-15/16 expression, can lead to targeted and combination therapies for the treatment of this incurable disease.
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http://dx.doi.org/10.1073/pnas.2003597117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7275703PMC
June 2020

Knockout of both miR-15/16 loci induces acute myeloid leukemia.

Proc Natl Acad Sci U S A 2018 12 26;115(51):13069-13074. Epub 2018 Nov 26.

Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH 43210;

MicroRNAs (miRNAs) have been extensively reported to be associated with hematological malignancies. The loss of miR-15a/16-1 at chromosome 13q14 is a hallmark of most of human chronic lymphocytic leukemia (CLL). Deletion of murine miR-15a/16-1 and miR-15b/16-2 has been demonstrated to promote B cell malignancies. Here, we evaluate the biological role of miR-15/16 clusters, crossbreeding miR-15a/16-1 and miR-15b/16-2 knockout mice. Unexpectedly, the complete deletion of both clusters promoted myeloproliferative disorders in the majority of the mice by the age of 5 months with a penetrance of 70%. These mice showed a significant enlargement of spleen and abnormal swelling of lymph nodes. Flow cytometry characterization demonstrated an expanded CD11b/Gr-1 double-positive myeloid population both in spleen and in bone marrow. The transplantation of splenocytes harvested from double-KO mice into wild-type recipient mice resulted in the development of myeloproliferative disorders, as observed in the donors. In vivo, miR-15/16 cluster deletion up-regulated the expression of Cyclin D1, Cyclin D2, and Bcl-2. Taken together, our findings identify a driver oncogenic role for miR-15/16 cluster deletion in different leukocytic cell lineages.
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http://dx.doi.org/10.1073/pnas.1814980115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6304943PMC
December 2018

The TLR7/8/9 Antagonist IMO-8503 Inhibits Cancer-Induced Cachexia.

Cancer Res 2018 12 12;78(23):6680-6690. Epub 2018 Sep 12.

Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

: Muscle wasting is a feature of the cachexia syndrome, which contributes significantly to the mortality of patients with cancer. We have previously demonstrated that miR-21 is secreted through extracellular vesicles (EV) by lung and pancreatic cancer cells and promotes JNK-dependent cell death through its binding to the TLR7 receptor in murine myoblasts. Here, we evaluate the ability of IMO-8503, a TLR7, 8, and 9 antagonist, to inhibit cancer-induced cachexia. Using EVs isolated from lung and pancreatic cancer cells and from patient plasma samples, we demonstrate that IMO-8503 inhibits cell death induced by circulating miRNAs with no significant toxicity. Intraperitoneal administration of the antagonist in a murine model for Lewis lung carcinoma (LLC-induced cachexia) strongly impaired several cachexia-related features, such as the expression of Pax7 as well as caspase-3 and PARP cleavage in skeletal muscles, and significantly prevented the loss of lean mass in tumor-bearing mice. IMO-8503 also impaired circulating miRNA-induced cell death in human primary myoblasts. Taken together, our findings strongly indicate that IMO-8503 serves as a potential therapy for the treatment of cancer cachexia. SIGNIFICANCE: Cancer-associated cachexia is a significant problem for patients with cancer that remain poorly understood, understudied, and inadequately treated; these findings report a potential new therapeutic for the treatment of TLR7-mediated cancer cachexia.
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http://dx.doi.org/10.1158/0008-5472.CAN-17-3878DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6541227PMC
December 2018

Exosome-Derived miR-25-3p and miR-92a-3p Stimulate Liposarcoma Progression.

Cancer Res 2017 07 6;77(14):3846-3856. Epub 2017 Jun 6.

The James Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

Despite the development of combined modality treatments against liposarcoma in recent years, a significant proportion of patients respond only modestly to such approaches, possibly contributing to local or distant recurrence. Early detection of recurrent or metastatic disease could improve patient prognosis by triggering earlier clinical intervention. However, useful biomarkers for such purposes are lacking. Using both patient plasma samples and cell lines, we demonstrate here that miR-25-3p and miR-92a-3p are secreted by liposarcoma cells through extracellular vesicles and may be useful as potential biomarkers of disease. Both miR-25-3p and miR-92a-3p stimulated secretion of proinflammatory cytokine IL6 from tumor-associated macrophages in a TLR7/8-dependent manner, which in turn promoted liposarcoma cell proliferation, invasion, and metastasis via this interaction with the surrounding microenvironment. Our findings provide novel and previously unreported insight into liposarcoma progression, identifying communication between liposarcoma cells and their microenvironment as a process critically involved in liposarcoma progression. This study establishes the possibility that the pattern of circulating miRNAs may identify recurrence prior to radiological detectability while providing insight into disease outcome and as a possible approach to monitor treatment efficacy. .
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http://dx.doi.org/10.1158/0008-5472.CAN-16-2984DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033276PMC
July 2017

ERK Activation Globally Downregulates miRNAs through Phosphorylating Exportin-5.

Cancer Cell 2016 Nov;30(5):723-736

Department of Cancer Biology and Genetics, Ohio State University, Columbus, OH 43210, USA. Electronic address:

MicroRNAs (miRNA) are mostly downregulated in cancer. However, the mechanism underlying this phenomenon and the precise consequence in tumorigenesis remain obscure. Here we show that ERK suppresses pre-miRNA export from the nucleus through phosphorylation of exportin-5 (XPO5) at T345/S416/S497. After phosphorylation by ERK, conformation of XPO5 is altered by prolyl isomerase Pin1, resulting in reduction of pre-miRNA loading. In liver cancer, the ERK-mediated XPO5 suppression reduces miR-122, increases microtubule dynamics, and results in tumor development and drug resistance. Analysis of clinical specimens further showed that XPO5 phosphorylation is associated with poor prognosis for liver cancer patients. Our study reveals a function of ERK in miRNA biogenesis and suggests that modulation of miRNA export has potential clinical implications.
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http://dx.doi.org/10.1016/j.ccell.2016.10.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5127275PMC
November 2016

WWOX and p53 Dysregulation Synergize to Drive the Development of Osteosarcoma.

Cancer Res 2016 10 22;76(20):6107-6117. Epub 2016 Aug 22.

The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel. Department of Cancer Biology and Genetics (CBG), The Ohio State University Wexner Medical Center, Columbus, Ohio. Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont.

Osteosarcoma is a highly metastatic form of bone cancer in adolescents and young adults that is resistant to existing treatments. Development of an effective therapy has been hindered by very limited understanding of the mechanisms of osteosarcomagenesis. Here, we used genetically engineered mice to investigate the effects of deleting the tumor suppressor Wwox selectively in either osteoblast progenitors or mature osteoblasts. Mice with conditional deletion of Wwox in preosteoblasts (Wwox) displayed a severe inhibition of osteogenesis accompanied by p53 upregulation, effects that were not observed in mice lacking Wwox in mature osteoblasts. Deletion of p53 in Wwox mice rescued the osteogenic defect. In addition, the Wwox;p53 double knockout mice developed poorly differentiated osteosarcomas that resemble human osteosarcoma in histology, location, metastatic behavior, and gene expression. Strikingly, the development of osteosarcomas in these mice was greatly accelerated compared with mice lacking p53 only. In contrast, combined WWOX and p53 inactivation in mature osteoblasts did not accelerate osteosarcomagenesis compared with p53 inactivation alone. These findings provide evidence that a WWOX-p53 network regulates normal bone formation and that disruption of this network in osteoprogenitors results in accelerated osteosarcoma. The Wwox;p53 double knockout establishes a new osteosarcoma model with significant advancement over existing models. Cancer Res; 76(20); 6107-17. ©2016 AACR.
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http://dx.doi.org/10.1158/0008-5472.CAN-16-0621DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5146760PMC
October 2016

Lung cancer exosomes as drivers of epithelial mesenchymal transition.

Oncotarget 2016 Aug;7(34):54852-54866

Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, The Ohio State University, Columbus, Ohio 43210, USA.

Exosomes, a subgroup of extracellular vesicles (EVs), have been shown to serve as a conduit for the exchange of genetic information between cells. Exosomes are released from all types of cells but in abundance from cancer cells. The contents of exosomes consist of proteins and genetic material (mRNA, DNA and miRNA) from the cell of origin. In this study, we examined the effects of exosomes derived from human lung cancer serum and both highly metastatic and non-metastatic cells on recipient human bronchial epithelial cells (HBECs). We found that exosomes derived from highly metastatic lung cancer cells and human late stage lung cancer serum induced vimentin expression, and epithelial to mesenchymal transition (EMT) in HBECs. Exosomes derived from highly metastatic cancer cells as well as late stage lung cancer serum induce migration, invasion and proliferation in non-cancerous recipient cells. Our results suggest that cancer derived exosomes could be a potential mediator of EMT in the recipient cells.
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http://dx.doi.org/10.18632/oncotarget.10243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5342386PMC
August 2016

A Fhit-mimetic peptide suppresses annexin A4-mediated chemoresistance to paclitaxel in lung cancer cells.

Oncotarget 2016 May;7(21):29927-36

Dipartimento di Medicina Sperimentale e Clinica, University Magna Græcia, Campus "S. Venuta", Catanzaro, Italy.

We recently reported that Fhit is in a molecular complex with annexin A4 (ANXA4); following to their binding, Fhit delocalizes ANXA4 from plasma membrane to cytosol in paclitaxel-resistant lung cancer cells, thus restoring their chemosensitivity to the drug. Here, we demonstrate that Fhit physically interacts with A4 through its N-terminus; molecular dynamics simulations were performed on a 3D Fhit model to rationalize its mechanism of action. This approach allowed for the identification of the QHLIKPS heptapeptide (position 7 to 13 of the wild-type Fhit protein) as the smallest Fhit sequence still able to preserve its ability to bind ANXA4. Interestingly, Fhit peptide also recapitulates the property of the native protein in inhibiting Annexin A4 translocation from cytosol to plasma membrane in A549 and Calu-2 lung cancer cells treated with paclitaxel. Finally, the combination of Tat-Fhit peptide and paclitaxel synergistically increases the apoptotic rate of cultured lung cancer cells and blocks in vivo tumor formation.Our findings address to the identification of chemically simplified Fhit derivatives that mimic Fhit tumor suppressor functions; intriguingly, this approach might lead to the generation of novel anticancer drugs to be used in combination with conventional therapies in Fhit-negative tumors to prevent or delay chemoresistance.
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http://dx.doi.org/10.18632/oncotarget.9179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5058653PMC
May 2016

microRNA classifiers are powerful diagnostic/prognostic tools in ALK-, EGFR-, and KRAS-driven lung cancers.

Proc Natl Acad Sci U S A 2015 Dec 16;112(48):14924-9. Epub 2015 Nov 16.

Comprehensive Cancer Center, Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210;

microRNAs (miRNAs) can act as oncosuppressors or oncogenes, induce chemoresistance or chemosensitivity, and are major posttranscriptional gene regulators. Anaplastic lymphoma kinase (ALK), EGF receptor (EGFR), and V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) are major drivers of non-small cell lung cancer (NSCLC). The aim of this study was to assess the miRNA profiles of NSCLCs driven by translocated ALK, mutant EGFR, or mutant KRAS to find driver-specific diagnostic and prognostic miRNA signatures. A total of 85 formalin-fixed, paraffin-embedded samples were considered: 67 primary NSCLCs and 18 matched normal lung tissues. Of the 67 primary NSCLCs, 17 were echinoderm microtubule-associated protein-like 4-ALK translocated (ALK(+)) lung cancers; the remaining 50 were not (ALK(-)). Of the 50 ALK(-) primary NSCLCs, 24 were EGFR and KRAS mutation-negative (i.e., WT; triple negative); 11 were mutant EGFR (EGFR(+)), and 15 were mutant KRAS (KRAS(+)). We developed a diagnostic classifier that shows how miR-1253, miR-504, and miR-26a-5p expression levels can classify NSCLCs as ALK-translocated, mutant EGFR, or mutant KRAS versus mutation-free. We also generated a prognostic classifier based on miR-769-5p and Let-7d-5p expression levels that can predict overall survival. This classifier showed better performance than the commonly used classifiers based on mutational status. Although it has several limitations, this study shows that miRNA signatures and classifiers have great potential as powerful, cost-effective next-generation tools to improve and complement current genetic tests. Further studies of these miRNAs can help define their roles in NSCLC biology and in identifying best-performing chemotherapy regimens.
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http://dx.doi.org/10.1073/pnas.1520329112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4672770PMC
December 2015

miR-15b/16-2 deletion promotes B-cell malignancies.

Proc Natl Acad Sci U S A 2015 Sep 31;112(37):11636-41. Epub 2015 Aug 31.

Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, OH 43210;

The central role of the microRNA (miR) 15a/16-1 cluster in B-cell oncogenesis has been extensively demonstrated, with over two-thirds of B-cell chronic lymphocytic leukemia characterized by the deletion of the miR-15a/16-1 locus at 13q14. Despite the well-established understanding of the molecular mechanisms occurring during miR-15a/16-1 dysregulation, the oncogenic role of other miR-15/16 family members, such as the miR-15b/16-2 cluster (3q25), is still far from being elucidated. Whereas miR-15a is highly similar to miR-15b, miR-16-1 is identical to miR-16-2; thus, it could be speculated that both clusters control a similar set of target genes and may have overlapping functions. However, the biological role of miR-15b/16-2 is still controversial. We generated miR-15b/16-2 knockout mice to better understand the cluster's role in vivo. These mice developed B-cell malignancy by age 15-18 mo with a penetrance of 60%. At this stage, mice showed significantly enlarged spleens with abnormal B cell-derived white pulp enlargement. Flow cytometric analysis demonstrated an expanded CD19+ CD5+ population in the spleen of 40% knockout mice, a characteristic of the chronic lymphocytic leukemia-associated phenotype found in humans. Of note, miR-15b/16-2 modulates the CCND2 (Cyclin D2), CCND1 (Cyclin D1), and IGF1R (insulin-like growth factor 1 receptor) genes involved in proliferation and antiapoptotic pathways in mouse B cells. These results are the first, to our knowledge, to suggest an important role of miR-15b/16-2 loss in the pathogenesis of B-cell chronic lymphocytic leukemia.
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http://dx.doi.org/10.1073/pnas.1514954112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4577143PMC
September 2015

miR-15b/16-2 regulates factors that promote p53 phosphorylation and augments the DNA damage response following radiation in the lung.

J Biol Chem 2014 Sep 4;289(38):26406-26416. Epub 2014 Aug 4.

Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, The Ohio State University, Columbus, Ohio 43210; James Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210. Electronic address:

MicroRNAs (miRNAs) are regulatory RNAs frequently dysregulated in disease and following cellular stress. Investigators have described changes in miR-15b expression following exposure to several stress-inducing anticancer agents, including ionizing radiation (IR), etoposide, and hydrogen peroxide. However, the role for miR-15b as a mediator of cellular injury in organs such as the lung has yet to be explored. In this study, we examined miR-15b expression patterns as well as its potential role in DNA damage and repair in the setting of IR exposure. We showed that miR-15b is up-regulated in a dose- and time-dependent manner in human bronchial epithelial cells following IR. miR-15b expression was highest after 2 h of IR and decreased gradually. Survival rates following IR were also higher in miR-15b/16-2-overexpressing cells. Cell cycle arrest in G2/M phase and an increased DNA repair response were observed in IR-exposed miR-15b/16-2 stable cells. We observed an up-regulation of components of the ataxia telangiectasia mutated (ATM)/Chek1/p53 pathway in miR-15b/16-2-overexpressing cells after IR. Moreover, a pathway-based PCR expression array of genes demonstrated that miR-15b/16-2 overexpression significantly induced the expression of genes involved in ATM/ataxia telangiectasia and Rad-3-related (ATR) signaling, apoptosis, the cell cycle, and DNA repair pathways. Here we demonstrated a novel biological link between miR-15b and DNA damage and cellular protection in lung cells. We identified Wip1 (PPM1D) as a functional target for miR-15b and determined that miR-15b induction of the DNA damage response is partially dependent upon suppression of Wip1. Our study suggests that miR-15b/Wip1 could be a potential therapeutic target in radiation-induced lung disease.
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http://dx.doi.org/10.1074/jbc.M114.573592DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4176210PMC
September 2014

Generation of mouse lines conditionally over-expressing microRNA using the Rosa26-Lox-Stop-Lox system.

Methods Mol Biol 2014 ;1194:203-24

Department of Molecular Virology, Immunology and Medical Genetics, Wexner Medical Center, Comprehensive Cancer Center, The Ohio State University, Biomedical Research Tower, Room 988, 460W. 12th Avenue, Columbus, OH, 43210, USA.

MicroRNAs are currently the object of intensive investigation due to their role in a myriad of physiological processes and pathological conditions, such as gene regulation and tumorigenesis. To better understand microRNA function, numerous laboratories have already taken advantage of the available techniques of genome editing in mouse. Here, we describe how to generate genetically engineered mouse lines using the popular Rosa-26 Lox-Stop-Lox Knock-In (Rosa-LSL-KI) targeting. This strategy allows for the selective overexpression of microRNAs of interest when coupled to a tissue-specific Cre-expressing line. The present protocol illustrates in detail both the engineering of the targeting vector and the generation of mutated ES clones ready for injection into mouse blastocysts.
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http://dx.doi.org/10.1007/978-1-4939-1215-5_11DOI Listing
March 2015

MicroRNA-135b promotes cancer progression by acting as a downstream effector of oncogenic pathways in colon cancer.

Cancer Cell 2014 Apr;25(4):469-83

Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK.

MicroRNA deregulation is frequent in human colorectal cancers (CRCs), but little is known as to whether it represents a bystander event or actually drives tumor progression in vivo. We show that miR-135b overexpression is triggered in mice and humans by APC loss, PTEN/PI3K pathway deregulation, and SRC overexpression and promotes tumor transformation and progression. We show that miR-135b upregulation is common in sporadic and inflammatory bowel disease-associated human CRCs and correlates with tumor stage and poor clinical outcome. Inhibition of miR-135b in CRC mouse models reduces tumor growth by controlling genes involved in proliferation, invasion, and apoptosis. We identify miR-135b as a key downsteam effector of oncogenic pathways and a potential target for CRC treatment.
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http://dx.doi.org/10.1016/j.ccr.2014.03.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3995091PMC
April 2014

Contact inhibition modulates intracellular levels of miR-223 in a p27kip1-dependent manner.

Oncotarget 2014 Mar;5(5):1185-97

Division of Experimental Oncology 2, CRO, National Cancer Institute, Aviano, Italy.

MicroRNAs (miRs) are a large class of small regulatory RNAs that function as nodes of signaling networks. This implicates that miRs expression has to be finely tuned, as observed during cell cycle progression. Here, using an expression profiling approach, we provide evidence that the CDK inhibitor p27Kip1 regulates miRs expression following cell cycle exit. By using wild type and p27KO cells harvested in different phases of the cell cycle we identified several miRs regulated by p27Kip1 during the G1 to S phase transition. Among these miRs, we identified miR-223 as a miR specifically upregulated by p27Kip1 in G1 arrested cells. Our data demonstrate that p27Kip1 regulated the expression of miR-223, via two distinct mechanisms. p27Kip1 directly stabilized mature miR-223 expression, acting as a RNA binding protein and it controlled E2F1 expression that, in turn, regulated miR-223 promoter activity. The resulting elevated miR-223 levels ultimately participated to arresting cell cycle progression following contact inhibition. Importantly, this mechanism of growth control was conserved in human cells and deranged in breast cancers. Here, we identify a novel and conserved function of p27Kip1 that, by modulating miR-223 expression, contributes to proper regulation of cell cycle exit following contact inhibition. Thus we propose a new role for miR-223 in the regulation of breast cancer progression.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012735PMC
http://dx.doi.org/10.18632/oncotarget.1803DOI Listing
March 2014

microRNA expression profiling identifies a four microRNA signature as a novel diagnostic and prognostic biomarker in triple negative breast cancers.

Oncotarget 2014 Mar;5(5):1174-84

Triple Negative Breast Cancers (TNBC) is a heterogeneous disease at the molecular and clinical level with poor outcome. Molecular subclassification of TNBCs is essential for optimal use of current therapies and for development of new drugs. microRNAs (miRNA) are widely recognized as key players in cancer progression and drug resistance; investigation of their involvement in a TNBC cohort may reveal biomarkers for diagnosis and prognosis of TNBC. Here we stratified a large TNBC cohort into Core Basal (CB, EGFR and/or CK5, 6 positive) and five negative (5NP) if all markers are negative. We determined the complete miRNA expression profile and found a subset of miRNAs specifically deregulated in the two subclasses.We identified a 4-miRNA signature given by miR-155, miR-493, miR-30e and miR-27a expression levels, that allowed subdivision of TNBCs not only into CB and 5NP subgroups (sensitivity 0.75 and specificity 0.56; AUC=0.74) but also into high risk and low risk groups. We tested the diagnostic and prognostic performances of both the 5 IHC marker panel and the 4-miRNA expression signatures, which clearly identify worse outcome patients in the treated and untreated subcohorts. Both signatures have diagnostic and prognostic value, predicting outcomes of patient treatment with the two most commonly used chemotherapy regimens in TNBC: anthracycline or anthracycline plus taxanes. Further investigations of the patients’ overall survival treated with these regimens show that regardless of IHC group subdivision, taxanes addition did not benefit patients, possibly due to miRNA driven taxanes resistance. TNBC subclassification based on the 5 IHC markers and on the miR-155, miR-493, miR-30e, miR-27a expression levels are powerful diagnostic tools. Treatment choice and new drug development should consider this new subtyping and miRNA expression signature in planning low toxicity, maximum efficacy therapies.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012726PMC
http://dx.doi.org/10.18632/oncotarget.1682DOI Listing
March 2014

Protective role of miR-155 in breast cancer through RAD51 targeting impairs homologous recombination after irradiation.

Proc Natl Acad Sci U S A 2014 Mar 10;111(12):4536-41. Epub 2014 Mar 10.

Department of Molecular Virology, Immunology and Medical Genetics, Wexner Medical Center and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210.

Cell survival after DNA damage relies on DNA repair, the abrogation of which causes genomic instability and development of cancer. However, defective DNA repair in cancer cells can be exploited for cancer therapy using DNA-damaging agents. DNA double-strand breaks are the major lethal lesions induced by ionizing radiation (IR) and can be efficiently repaired by DNA homologous recombination, a system that requires numerous factors including the recombinase RAD51 (RAD51). Therapies combined with adjuvant radiotherapy have been demonstrated to improve the survival of triple-negative breast cancer patients; however, such therapy is challenged by the emergence of resistance in tumor cells. It is, therefore, essential to develop novel therapeutic strategies to overcome radioresistance and improve radiosensitivity. In this study we show that overexpression of microRNA 155 (miR-155) in human breast cancer cells reduces the levels of RAD51 and affects the cellular response to IR. miR-155 directly targets the 3'-untranslated region of RAD51. Overexpression of miR-155 decreased the efficiency of homologous recombination repair and enhanced sensitivity to IR in vitro and in vivo. High miR-155 levels were associated with lower RAD51 expression and with better overall survival of patients in a large series of triple-negative breast cancers. Taken together, our findings indicate that miR-155 regulates DNA repair activity and sensitivity to IR by repressing RAD51 in breast cancer. Testing for expression levels of miR-155 may be useful in the identification of breast cancer patients who will benefit from an IR-based therapeutic approach.
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http://dx.doi.org/10.1073/pnas.1402604111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970505PMC
March 2014

Androgen receptor status is a prognostic marker in non-basal triple negative breast cancers and determines novel therapeutic options.

PLoS One 2014 5;9(2):e88525. Epub 2014 Feb 5.

Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center and Comprehensive Cancer Center, Columbus, Ohio, United States of America.

Triple negative breast cancers are a heterogeneous group of tumors characterized by poor patient survival and lack of targeted therapeutics. Androgen receptor has been associated with triple negative breast cancer pathogenesis, but its role in the different subtypes has not been clearly defined. We examined androgen receptor protein expression by immunohistochemical analysis in 678 breast cancers, including 396 triple negative cancers. Fifty matched lymph node metastases were also examined. Association of expression status with clinical (race, survival) and pathological (basal, non-basal subtype, stage, grade) features was also evaluated. In 160 triple negative breast cancers, mRNA microarray expression profiling was performed, and differences according to androgen receptor status were analyzed. In triple negative cancers the percentage of androgen receptor positive cases was lower (24.8% vs 81.6% of non-triple negative cases), especially in African American women (16.7% vs 25.5% of cancers of white women). No significant difference in androgen receptor expression was observed in primary tumors vs matched metastatic lesions. Positive androgen receptor immunoreactivity was inversely correlated with tumor grade (p<0.01) and associated with better overall patient survival (p = 0.032) in the non-basal triple negative cancer group. In the microarray study, expression of three genes (HER4, TNFSF10, CDK6) showed significant deregulation in association with androgen receptor status; eg CDK6, a novel therapeutic target in triple negative cancers, showed significantly higher expression level in androgen receptor negative cases (p<0.01). These findings confirm the prognostic impact of androgen receptor expression in non-basal triple negative breast cancers, and suggest targeting of new androgen receptor-related molecular pathways in patients with these cancers.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088525PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3914993PMC
September 2014

LZTS1 downregulation confers paclitaxel resistance and is associated with worse prognosis in breast cancer.

Oncotarget 2014 Feb;5(4):970-7

Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center and Comprehensive Cancer Center, Columbus, Ohio, USA.

The Leucine Zipper Tumor Suppressor 1 (LZTS1) is a tumor suppressor gene, located at chromosome 8p22, which is frequently altered in human cancer. In normal tissue, its ubiquitous expression regulates cell mitosis by the stabilization of microtubule networks. LZTS1-deficient mouse embryonic fibroblasts have been shown to have an accelerated mitotic progression, and a higher resistance to taxanes, microtubule-stabilizing drugs. We investigate the role of Lzts1 in paclitaxel-resistance in breast cancer cells. Downregulation of Lzts1 expression significantly decreases sensitivity to paclitaxel in vitro. We further analyzed Lzts1 expression by immunohistochemistry in 270 primary breast cancer samples and 16 normal breast specimens. Lzts1 was significantly downregulated in breast cancer samples and its deregulation was associated with a higher incidence of tumor recurrence, and to a worse overall survival. Moreover, Lzts1-negative tumors were associated with unfavorable outcome after taxanes-based therapy. Thus our data suggest that Lzts1 deregulation is involved in breast cancer and its immunohistochemical evaluation may serve as a prognostic factor for breast cancer therapy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4011598PMC
http://dx.doi.org/10.18632/oncotarget.1630DOI Listing
February 2014

Fhit delocalizes annexin a4 from plasma membrane to cytosol and sensitizes lung cancer cells to paclitaxel.

PLoS One 2013 6;8(11):e78610. Epub 2013 Nov 6.

Department of Molecular Immunology, Virology and Medical Genetics, The Ohio State University, Columbus, Ohio, United States of America ; Lymphoma and Genomics Research Program, IOR Institute of Oncology Research, Bellinzona, Switzerland ; Dipartimento di Medicina Sperimentale e Clinica, University Magna Græcia, Campus "S. Venuta", Catanzaro, Italy.

Fhit protein is lost or reduced in a large fraction of human tumors, and its restoration triggers apoptosis and suppresses tumor formation or progression in preclinical models. Here, we describe the identification of candidate Fhit-interacting proteins with cytosolic and plasma membrane localization. Among these, Annexin 4 (ANXA4) was validated by co-immunoprecipitation and confocal microscopy as a partner of this novel Fhit protein complex. Here we report that overexpression of Fhit prevents Annexin A4 translocation from cytosol to plasma membrane in A549 lung cancer cells treated with paclitaxel. Moreover, paclitaxel administration in combination with AdFHIT acts synergistically to increase the apoptotic rate of tumor cells both in vitro and in vivo experiments.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0078610PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3819369PMC
August 2014

B-cell malignancies in microRNA Eμ-miR-17~92 transgenic mice.

Proc Natl Acad Sci U S A 2013 Nov 21;110(45):18208-13. Epub 2013 Oct 21.

Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH 43210.

miR-17∼92 is a polycistronic microRNA (miR) cluster (consisting of miR-17, miR-18a, miR-19a, miR-19b, miR-20a, and miR-92a) which frequently is overexpressed in several solid and lymphoid malignancies. Loss- and gain-of-function studies have revealed the role of miR-17∼92 in heart, lung, and B-cell development and in Myc-induced B-cell lymphomas, respectively. Recent studies indicate that overexpression of this locus leads to lymphoproliferation, but no experimental proof that dysregulation of this cluster causes B-cell lymphomas or leukemias is available. To determine whether miR-17∼92- overexpression induces lymphomagenesis/leukemogenesis, we generated a B-cell-specific transgenic mouse model with targeted overexpression of this cluster in B cells. The miR-17∼92 overexpression was driven by the Eµ-enhancer and Ig heavy-chain promoter, and a 3' GFP tag was added to the transgene to track the miR expression. Expression analysis using Northern Blot and quantitative RT-PCR confirmed 2.5- to 25-fold overexpression of all six miRs in the transgenic mice spleens as compared with spleens from wild-type mice. Eµ-miR-17∼92 mice developed B-cell malignancy by the age of 12-18 mo with a penetrance of ∼80% (49% splenic B-cell lymphoproliferative disease, 28% lymphoma). At this stage mice exhibited severe splenomegaly with abnormal B-cell-derived white pulp expansion and enlarged lymph nodes. Interestingly, we found three classes of B-cell lymphomas/leukemias at varying grades of differentiation. These included expansion of CD19(+) and CD5(+) double-positive B cells similar to the aggressive form of human B-cell chronic lymphocytic leukemia, B220(+) CD43(+) B1-cell proliferation, and a CD19(+) aggressive diffuse large B-cell lymphoma-like disease, as assessed by flow cytometry and histopathological analysis.
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http://dx.doi.org/10.1073/pnas.1315365110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3831438PMC
November 2013

Non-coding RNAs and cancer.

Int J Mol Sci 2013 Aug 19;14(8):17085-110. Epub 2013 Aug 19.

Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, Ohio State University, Columbus, OH 43210, USA.

The discovery of the biological relevance of non-coding RNA (ncRNAs) molecules represents one of the most significant advances in contemporary molecular biology. Expression profiling of human tumors, based on the expression of miRNAs and other short or long ncRNAs, has identified signatures associated with diagnosis, staging, progression, prognosis, and response to treatment. In this review we will discuss the recent remarkable advancement in the understanding the biological functions of human ncRNAs in cancer, the mechanisms of expression and the therapeutic potential.
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http://dx.doi.org/10.3390/ijms140817085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3759953PMC
August 2013

Angiotensin-converting-enzyme inhibition counteracts angiotensin II-mediated endothelial cell dysfunction by modulating the p38/SirT1 axis.

J Hypertens 2013 Oct;31(10):1972-83

aDepartment of Applied Clinical Sciences and Biotechnology, University of L'Aquila bDepartment MeSVA, University of L'Aquila, L'Aquila, Italy cDepartment of Molecular Immunology, Virology, and Medical Genetics, The Ohio State University, Columbus, Ohio, USA dPreclinical Development Department, Menarini Ricerche, Firenze, Italy *Francesco Marampon and Giovanni L. Gravina contributed equally to the writing of this article.

Objective: Oxidative stress has been linked to endothelial dysfunction and angiotensin II stimulates the reactive oxygen species production contributing to several cardiovascular diseases. We have studied the chain of events induced by angiotensin-converting-enzyme (ACE) activation in vascular umbilical vein endothelial cells (HUVECs) by using an ACE inhibitor such as zofenoprilat.

Methods: We used specific assay to measure the superoxide anion production, tetrazolium bromide (MTT) assay for cell viability, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay for cell apoptosis, and western blot for protein analysis in the study.

Results: Zofenoprilat counteracts the superoxide anion production and cell apoptosis induced by angiotensin I treatment by blocking the extrinsic caspase cascade, NF-kB and p38 activation. p38 inhibitor SB203580 reverted the angiotensin II oxidant effects while the p38 constitutively activation, by MKK6 transfection, abrogated the zofenoprilat effects. Characterizing the zofenoprilat downstream effector we found that zofenoprilat reverted the SirT-1 downregulation induced by angiotensin II. p38 activation by angiotensin II was strictly correlated with SirT1 protein downregulation; SB203580 significantly prevented SirT1 downregulation induced by angiotensin II while the p38 constitutive activation abolished SIRT1 protein basal levels. p38 directly bound SirT1 sequestering it in the cytoplasm. SirT1 inhibition by sirtinol annulled zofenoprilat action while SirT1 overexpression reverted the cytotoxic effects of angiotensin II. Finally, zofenoprilat negatively controlled angiotensin I receptor protein expression through SirT1.

Conclusion: The p38-SirT1 axis is found markedly relevant in modulating the cardiovascular benefit deriving from ACE-inhibitors and might represent a novel target for innovative drugs in cardiovascular prevention.
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http://dx.doi.org/10.1097/HJH.0b013e3283638b32DOI Listing
October 2013

Toll-like receptor 3 (TLR3) activation induces microRNA-dependent reexpression of functional RARβ and tumor regression.

Proc Natl Acad Sci U S A 2013 Jun 28;110(24):9812-7. Epub 2013 May 28.

Department of Anatomical, Histological, Forensic & Orthopaedic Sciences, DAHFMO, Unit of Histology and Medical Embryology, Istituto Pasteur-Fondazione Cenci Bolognetti, La Sapienza University of Rome, 00161 Rome, Italy.

Toll-like receptor 3 (TLR3) is a key effector of the innate immune system against viruses. Activation of TLR3 exerts an antitumoral effect through a mechanism of action still poorly understood. Here we show that TLR3 activation by polyinosinic:polycytidylic acid induces up-regulation of microRNA-29b, -29c, -148b, and -152 in tumor-derived cell lines and primary tumors. In turn, these microRNAs induce reexpression of epigenetically silenced genes by targeting DNA methyltransferases. In DU145 and TRAMP-C1 prostate and MDA-MB-231 breast cancer cells, we demonstrated that polyinosinic:polycytidylic acid-mediated activation of TLR3 induces microRNAs targeting DNA methyltransferases, leading to demethylation and reexpression of the oncosuppressor retinoic acid receptor beta (RARβ). As a result, cancer cells become sensitive to retinoic acid and undergo apoptosis both in vitro and in vivo. This study provides evidence of an antitumoral mechanism of action upon TLR3 activation and the biological rationale for a combined TLR3 agonist/retinoic acid treatment of prostate and breast cancer.
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http://dx.doi.org/10.1073/pnas.1304610110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683754PMC
June 2013

A microRNA signature defines chemoresistance in ovarian cancer through modulation of angiogenesis.

Proc Natl Acad Sci U S A 2013 Jun 22;110(24):9845-50. Epub 2013 May 22.

Division of Pathology and Medical Oncology, Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, University Sapienza, Santo Andrea Hospital, 00100 Rome, Italy.

Epithelial ovarian cancer is the most lethal gynecologic malignancy; it is highly aggressive and causes almost 125,000 deaths yearly. Despite advances in detection and cytotoxic therapies, a low percentage of patients with advanced stage disease survive 5 y after the initial diagnosis. The high mortality of this disease is mainly caused by resistance to the available therapies. Here, we profiled microRNA (miR) expression in serous epithelial ovarian carcinomas to assess the possibility of a miR signature associated with chemoresistance. We analyzed tumor samples from 198 patients (86 patients as a training set and 112 patients as a validation set) for human miRs. A signature of 23 miRs associated with chemoresistance was generated by array analysis in the training set. Quantitative RT-PCR in the validation set confirmed that three miRs (miR-484, -642, and -217) were able to predict chemoresistance of these tumors. Additional analysis of miR-484 revealed that the sensitive phenotype is caused by a modulation of tumor vasculature through the regulation of the VEGFB and VEGFR2 pathways. We present compelling evidence that three miRs can classify the response to chemotherapy of ovarian cancer patients in a large multicenter cohort and that one of these three miRs is involved in the control of tumor angiogenesis, indicating an option in the treatment of these patients. Our results suggest, in fact, that blockage of VEGF through the use of an anti-VEGFA antibody may not be sufficient to improve survival in ovarian cancer patients unless VEGFB signaling is also blocked.
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http://dx.doi.org/10.1073/pnas.1305472110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683704PMC
June 2013

Stathmin regulates mutant p53 stability and transcriptional activity in ovarian cancer.

EMBO Mol Med 2013 May 22;5(5):707-22. Epub 2013 Apr 22.

Division of Experimental Oncology 2, Centro di Riferimento Oncologico, National Cancer Institute, Aviano, Italy.

Stathmin is a p53-target gene, frequently overexpressed in late stages of human cancer progression. Type II High Grade Epithelial Ovarian Carcinomas (HG-EOC) represents the only clear exception to this observation. Here, we show that stathmin expression is necessary for the survival of HG-EOC cells carrying a p53 mutant (p53(MUT) ) gene. At molecular level, stathmin favours the binding and the phosphorylation of p53(MUT) by DNA-PKCS , eventually modulating p53(MUT) stability and transcriptional activity. Inhibition of stathmin or DNA-PKCS impaired p53(MUT) -dependent transcription of several M phase regulators, resulting in M phase failure and EOC cell death, both in vitro and in vivo. In primary human EOC a strong correlation exists between stathmin, DNA-PKCS , p53(MUT) overexpression and its transcriptional targets, further strengthening the relevance of the new pathway here described. Overall our data support the hypothesis that the expression of stathmin and p53 could be useful for the identification of high risk patients that will benefit from a therapy specifically acting on mitotic cancer cells.
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http://dx.doi.org/10.1002/emmm.201201504DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3662314PMC
May 2013

Integrated microRNA and mRNA signatures associated with survival in triple negative breast cancer.

PLoS One 2013 6;8(2):e55910. Epub 2013 Feb 6.

Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America.

Triple negative breast cancer (TNBC) is a heterogeneous disease at the molecular, pathologic and clinical levels. To stratify TNBCs, we determined microRNA (miRNA) expression profiles, as well as expression profiles of a cancer-focused mRNA panel, in tumor, adjacent non-tumor (normal) and lymph node metastatic lesion (mets) tissues, from 173 women with TNBCs; we linked specific miRNA signatures to patient survival and used miRNA/mRNA anti-correlations to identify clinically and genetically different TNBC subclasses. We also assessed miRNA signatures as potential regulators of TNBC subclass-specific gene expression networks defined by expression of canonical signal pathways.Tissue specific miRNAs and mRNAs were identified for normal vs tumor vs mets comparisons. miRNA signatures correlated with prognosis were identified and predicted anti-correlated targets within the mRNA profile were defined. Two miRNA signatures (miR-16, 155, 125b, 374a and miR-16, 125b, 374a, 374b, 421, 655, 497) predictive of overall survival (P = 0.05) and distant-disease free survival (P = 0.009), respectively, were identified for patients 50 yrs of age or younger. By multivariate analysis the risk signatures were independent predictors for overall survival and distant-disease free survival. mRNA expression profiling, using the cancer-focused mRNA panel, resulted in clustering of TNBCs into 4 molecular subclasses with different expression signatures anti-correlated with the prognostic miRNAs. Our findings suggest that miRNAs play a key role in triple negative breast cancer through their ability to regulate fundamental pathways such as: cellular growth and proliferation, cellular movement and migration, Extra Cellular Matrix degradation. The results define miRNA expression signatures that characterize and contribute to the phenotypic diversity of TNBC and its metastasis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0055910PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3566108PMC
August 2013

Heat shock protein 70 regulates Tcl1 expression in leukemia and lymphomas.

Blood 2013 Jan 15;121(2):351-9. Epub 2012 Nov 15.

Department of Molecular Immunology, Virology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA.

T-cell leukemia/lymphoma 1 (TCL1) is an oncogene overexpressed in T-cell prolymphocytic leukemia and in B-cell malignancies including B-cell chronic lymphocytic leukemia and lymphomas. To date, only a limited number of Tcl1-interacting proteins that regulate its oncogenic function have been identified. Prior studies used a proteomic approach to identify a novel interaction between Tcl1 with Ataxia Telangiectasia Mutated. The association of Tcl1 and Ataxia Telangiectasia Mutated leads to activation of the NF-κB pathway. Here, we demonstrate that Tcl1 also interacts with heat shock protein (Hsp) 70. The Tcl1-Hsp70 complex was validated by coimmunoprecipitation experiments. In addition, we report that Hsp70, a protein that plays a critical role in the folding and maturation of several oncogenic proteins, associates with Tcl1 protein and stabilizes its expression. The inhibition of the ATPase activity of Hsp70 results in ubiquitination and proteasome-dependent degradation of Tcl1. The inhibition of Hsp70 significantly reduced the growth of lymphoma xenografts in vivo and down-regulated the expression of Tcl1 protein. Our findings reveal a functional interaction between Tcl1 and Hsp70 and identify Tcl1 as a novel Hsp70 client protein. These findings suggest that inhibition of Hsp70 may represent an alternative effective therapy for chronic lymphocytic leukemia and lymphomas via its ability to inhibit the oncogenic functions of Tcl1.
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http://dx.doi.org/10.1182/blood-2012-09-457374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3544116PMC
January 2013

MicroRNAs bind to Toll-like receptors to induce prometastatic inflammatory response.

Proc Natl Acad Sci U S A 2012 Jul 2;109(31):E2110-6. Epub 2012 Jul 2.

Department of Molecular Virology, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA.

MicroRNAs (miRNAs) are small noncoding RNAs, 19-24 nucleotides in length, that regulate gene expression and are expressed aberrantly in most types of cancer. MiRNAs also have been detected in the blood of cancer patients and can serve as circulating biomarkers. It has been shown that secreted miRNAs within exosomes can be transferred from cell to cell and can regulate gene expression in the receiving cells by canonical binding to their target messenger RNAs. Here we show that tumor-secreted miR-21 and miR-29a also can function by another mechanism, by binding as ligands to receptors of the Toll-like receptor (TLR) family, murine TLR7 and human TLR8, in immune cells, triggering a TLR-mediated prometastatic inflammatory response that ultimately may lead to tumor growth and metastasis. Thus, by acting as paracrine agonists of TLRs, secreted miRNAs are key regulators of the tumor microenvironment. This mechanism of action of miRNAs is implicated in tumor-immune system communication and is important in tumor growth and spread, thus representing a possible target for cancer treatment.
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http://dx.doi.org/10.1073/pnas.1209414109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3412003PMC
July 2012

miRNA signatures associate with pathogenesis and progression of osteosarcoma.

Cancer Res 2012 Apr 20;72(7):1865-77. Epub 2012 Feb 20.

Department of Orthopaedics and Center for Children's Cancer Research, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, USA.

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.
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http://dx.doi.org/10.1158/0008-5472.CAN-11-2663DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3328547PMC
April 2012