Angela Cordella

Leptin as a mediator of tumor-stromal interactions promotes breast cancer stem cell activity

Breast cancer stem cells (BCSCs) play crucial roles in tumor initiation, metastasis and therapeutic resistance. A strict dependency between BCSCs and stromal cell components of tumor microenvironment exists. Thus, novel therapeutic strategies aimed to target the crosstalk between activated microenvironment and BCSCs have the potential to improve clinical outcome. Here, we investigated how leptin, as a mediator of tumor-stromal interactions, may affect BCSC activity using patient-derived samples (n = 16) and breast cancer cell lines, and determined the potential benefit of targeting leptin signaling in these model systems. Conditioned media (CM) from cancer-associated fibroblasts and breast adipocytes significantly increased mammosphere formation in breast cancer cells and depletion of leptin from CM completely abrogated this effect. Mammosphere cultures exhibited increased leptin receptor (OBR) expression and leptin exposure enhanced mammosphere formation. Microarray analyses revealed a similar expression profile of genes involved in stem cell biology among mammospheres treated with CM and leptin. Interestingly, leptin increased mammosphere formation in metastatic breast cancers and expression of OBR as well as HSP90, a target of leptin signaling, were directly correlated with mammosphere formation in metastatic samples (r = 0.68/p = 0.05; r = 0.71/p = 0.036, respectively). Kaplan–Meier survival curves indicated that OBR and HSP90 expression were associated with reduced overall survival in breast cancer patients (HR = 1.9/p = 0.022; HR = 2.2/p = 0.00017, respectively). Furthermore, blocking leptin signaling by using a full leptin receptor antagonist significantly reduced mammosphere formation in breast cancer cell lines and patient-derived samples. Our results suggest that leptin/leptin receptor signaling may represent a potential therapeutic target that can block the stromal-tumor interactions driving BCSC-mediated disease progression.

Timed regulation of P‐element‐induced wimpy testis–interacting RNA expression during rat liver regeneration

Small noncoding RNAs comprise a growing family of molecules that regulate key cellular processes, including messenger RNA (mRNA) degradation, translational repression, and transcriptional gene silencing. P‐element‐induced wimpy testis (PIWI)‐interacting RNAs (piRNAs) represent a class of small RNAs initially identified in the germline of a variety of species, where they contribute to maintenance of genome stability, and recently found expressed also in stem and somatic cells, where their role and responsiveness to physiopathological signals remain elusive. Here, we investigated piRNA expression in rat liver and its response to the stimuli exerted by regenerative proliferation of this organ. Quantitative polymerase chain reaction analysis identify in the liver the RNAs encoding PIWIL2/HILI, PIWIL4/HIWI2, and other components of the piRNA biogenesis pathways, suggesting that this is indeed functional. RNA sequencing before, during, and after the wave of cell proliferation that follows partial hepatectomy (PH) identified ∼1,400 mammalian germline piRNAs expressed in rat liver, including 72 showing timed changes in expression 24‐48 hours post‐PH, a timing that corresponds to cell transition through the S phase, returning to basal levels by 168 hours, when organ regeneration is completed and hepatocytes reach quiescence. Conclusion: The piRNA pathway is active in somatic cells of the liver and is subject to regulation during the pathophysiological process of organ regeneration, when these molecules are available to exert their regulatory functions on the cell genome and transcriptome, as demonstrated by the identification of several liver mRNAs representing candidate targets of these regulatory RNAs. (Hepatology 2014;60:798–806)

Specific patterns of PIWI-interacting small noncoding RNA expression in dysplastic liver nodules and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the result of a stepwise process, often beginning with development within a cirrhotic liver of premalignant lesions, morphologically characterized by low- (LGDN) and high-grade (HGDN) dysplastic nodules. PIWI-interacting RNAs (piRNAs) are small noncoding RNAs (sncRNAs), 23–35 nucleotide-long, exerting epigenetic and post-transcriptional regulation of gene expression. Recently the PIWI-piRNA pathway, best characterized in germline cells, has been identified also in somatic tissues, including stem and cancer cells, where it influences key cellular processes. Small RNA sequencing was applied to search for liver piRNAs and to profile their expression patterns in cirrhotic nodules (CNs), LGDN, HGDN, early HCC and progressed HCC (pHCC), analyzing 55 samples (14 CN, 9 LGDN, 6 HGDN, 6 eHCC and 20 pHCC) from 17 patients, aiming at identifying possible relationships between these sncRNAs and liver carcinogenesis. We identified a 125 piRNA expression signature that characterize HCC from matched CNs, correlating also to microvascular invasion in HCC. Functional analysis of the predicted RNA targets of deregulated piRNAs indicates that these can target key signaling pathways involved in hepatocarcinogenesis and HCC progression, thereby affecting their activity. Interestingly, 24 piRNAs showed specific expression patterns in dysplastic nodules, respect to cirrhotic liver and/or pHCC. The results demonstrate that the PIWI-piRNA pathway is active in human liver, where it represents a new player in the molecular events that characterize hepatocarcinogenesis, from early stages to pHCC. Furthermore, they suggest that piRNAs might be new disease biomarkers, useful for differential diagnosis of dysplastic and neoplastic liver lesions.

Identification of cytoplasmic proteins interacting with unliganded estrogen receptor α and β in human breast cancer cells

Estrogen receptor subtypes (ERα and ERβ) are transcription factors sharing a similar structure but exerting opposite roles in breast cancer cells. Besides the well‐characterized genomic actions of nuclear ERs upon ligand binding, specific actions of ligand‐free ERs in the cytoplasm also affect cellular functions. The identification of cytoplasmic interaction partners of unliganded ERα and ERβ may help characterize the molecular basis of the extra‐nuclear mechanism of action of these receptors, revealing novel mechanisms to explain their role in breast cancer response or resistance to endocrine therapy. To this aim, cytoplasmic extracts from human breast cancer MCF‐7 cells stably expressing tandem affinity purification‐tagged ERα and ERβ and maintained in estrogen‐free medium were subject to affinity‐purification and MS analysis, leading to the identification of 84 and 142 proteins associated with unliganded ERα and ERβ, respectively. Functional analyses of ER subtype‐specific interactomes revealed significant differences in the molecular pathways targeted by each receptor in the cytoplasm. This work, reporting the first identification of the unliganded ERα and ERβ cytoplasmic interactomes in breast cancer cells, provides novel experimental evidence on the nongenomic effects of ERs in the absence of hormonal stimulus. All MS data have been deposited in the ProteomeXchange with identifier PXD001202 (http://proteomecentral.proteomexchange.org/dataset/PXD001202).

The nuclear receptor ERβ engages AGO2 in regulation of gene transcription, RNA splicing and RISC loading

BackgroundThe RNA-binding protein Argonaute 2 (AGO2) is a key effector of RNA-silencing pathways It exerts a pivotal role in microRNA maturation and activity and can modulate chromatin remodeling, transcriptional gene regulation and RNA splicing. Estrogen receptor beta (ERβ) is endowed with oncosuppressive activities, antagonizing hormone-induced carcinogenesis and inhibiting growth and oncogenic functions in luminal-like breast cancers (BCs), where its expression correlates with a better prognosis of the disease.ResultsApplying interaction proteomics coupled to mass spectrometry to characterize nuclear factors cooperating with ERβ in gene regulation, we identify AGO2 as a novel partner of ERβ in human BC cells. ERβ–AGO2 association was confirmed in vitro and in vivo in both the nucleus and cytoplasm and is shown to be RNA-mediated. ChIP-Seq demonstrates AGO2 association with a large number of ERβ binding sites, and total and nascent RNA-Seq in ERβ + vs ERβ − cells, and before and after AGO2 knock-down in ERβ + cells, reveals a widespread involvement of this factor in ERβ-mediated regulation of gene transcription rate and RNA splicing. Moreover, isolation and sequencing by RIP-Seq of ERβ-associated long and small RNAs in the cytoplasm suggests involvement of the nuclear receptor in RISC loading, indicating that it may also be able to directly control mRNA translation efficiency and stability.ConclusionsThese results demonstrate that AGO2 can act as a pleiotropic functional partner of ERβ, indicating that both factors are endowed with multiple roles in the control of key cellular functions.

Global gene expression profile of normal and regenerating liver in young and old mice

The ability of the liver to regenerate and adjust its size after two/third partial hepatectomy (PH) is impaired in old rodents and humans. Here, we investigated by microarray analysis the expression pattern of hepatic genes in young and old untreated mice and the differences in gene expression profile following PH. Of the 10,237 messenger RNAs that had detectable expression, only 108 displayed a greater than 2-fold modification in gene expression levels between the two groups. These genes were involved in inflammatory and immune response, xenobiotics, and lipid and glucose metabolism. To identify the genes responsible for the different regenerative response, 10-week and 18-month-old mice subjected to PH were sacrificed at different time intervals after surgery. The results showed that 2463 transcripts had significantly different expression post PH between the two groups. However, in spite of impaired liver regeneration in old mice, cell cycle genes were similarly modified in both groups, the only exception being cyclin D1 gene which was up-regulated soon after PH in young mice, but mostly down-regulated in aged animals. Surprisingly, while in young hepatectomized mice, Yap messenger RNA (mRNA) expression was not significantly enhanced and protein expression essentially reflected the progression into cell cycle, its mRNA and protein levels were robustly increased in the liver of aged animals. Furthermore, a significant change of the age-related expression of the size regulator Yes-associated protein (YAP) was observed. Unexpectedly, while in young hepatectomized mice, Yap mRNA expression was not significantly enhanced and protein expression essentially reflected the progression into cell cycle, its mRNA and protein levels were robustly increased in the liver of aged animals. Moreover, when PH was performed on mitogen-induced enlarged livers, the earlier restoration of the original liver mass compared to animals subjected to PH only led to YAP down-regulation concomitantly with cyclin D1 up-regulation. Our data suggest that YAP activation is a size-dependent homeostatic mechanism that does not necessarily reflect cell cycle progression.

Efficacy of pharmacological treatment and genetic characterization in early diagnosed patients affected by long QT syndrome with impaired AV conduction

cardiac autonomic control in patients with subclinical and overt hyperthyroidism. Eur J Endocrinol 2001;145:691–6. [15] Biondi B. Should we treat all subjects with subclinical thyroid disease the same way? Eur J Endocrinol Sep 2008;159(3):343–5 Electronic publication 2008 Jul 22. [16] Haentjens P, Van Meerhaeghe A, Poppe K, Velkeniers B. Subclinical thyroid dysfunction and mortality: an estimate of relative and absolute excess all-cause mortality based on time-to-event data from cohort studies. Eur J Endocrinol Sep 2008;159(3):329–41 Electronic publication 2008 May 29. [17] Patane S, Marte F, Di Bella G, Turiano G. Acute myocardial infarction and subclinical hyperthyroidism without significant coronary stenoses. Int J Cardiol 2009 May 29;134(3):e135–7 [Electronic Publication ahead of print 2008 Jun 24]. [18] Patane S, Marte F. Paroxysmal atrial fibrillation during acute myocardial infarction associated with subclinical hyperthyroidism, severe three vessels coronary artery disease and elevation of prostate-specific antigen after Turp. Int J Cardiol 2010;138:e28–30. [19] Patane S, Marte F. Paroxysmal ventricular tachycardia and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism, chronic renal failure and elevation of prostate-specific antigen during acute myocardial infarction. Int J Cardiol 2010 Feb 4;138(3):e44–6 [Electronic Publication ahead of print 2008 Aug 21]. [20] Patane S, Marte F. Atrial fibrillation associated with subclinical hyperthyroidism. Int J Cardiol 2009 May 29;134(3):e155–8 [Electronic Publication ahead of print 2009 Jan 29]. [21] Patane S, Marte F. Intermittent changing axis deviationwith intermittent left anterior hemiblock during atrial flutter with subclinical hyperthyroidism. Int J Cardiol 2009 Jun 26;135(2):e37–9 [Electronic Publication ahead of print 2008 Jan 24]. [22] Patane S, Marte F. Changing axis deviation and paroxysmal atrial flutter associated with subclinical hyperthyroidism. Int J Cardiol 2010 Oct 8;144(2):e31–3 [Electronic Publication ahead of print 2009 Jan 26]. [23] Erem C. Blood coagulation, fibrinolytic activity and lipid profile in subclinical thyroid disease: subclinical hyperthyroidism increases plasma factor X activity. Clin Endocrinol (Oxf) Mar 2006;64(3):323–9. [24] Coban E, Aydemir M, Yazicioglu G, Ozdogan M. Endothelial dysfunction in subjects with subclinical hyperthyroidism. J Endocrinol Invest Mar 2006;29(3):197–200. [25] Coban E, Aydemir M. Levels of plasma fibrinogen and D-dimer in subjects with subclinical hyperthyroidism. Med Sci Monit Jan 2008;14(1):CR42–46. [26] Patane S, Marte F. Atrial fibrillation and acute myocardial infarction without significant coronary stenoses associated with subclinical hyperthyroidism and erythrocytosis. Int J Cardiol 2010 Nov 5;145(1):e36–9 [Electronic Publication ahead of print 2009 Jan 30]. [27] Patane S, Marte F, Curro A, Cimino C. Recurrent acute pulmonary embolism and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism. Int J Cardiol 2010 Jul 9;142(2):e25–6 [Electronic Publication ahead of print 2009 Jan 9]. [28] Coats AJ. Ethical authorship and publishing. Int J Cardiol 2009;131:149–50.

Identification of a novel truncating mutation in PALB2 gene by a multigene sequencing panel for mutational screening of breast cancer risk-associated and related genes

Breast cancer (BC) is the most common neoplasm in women, with 5%‐10% patients showing a familial predisposition, where germline mutations in BRCA1/BRCA2 genes are found in –20% of cases. Next‐generation sequencing (NGS) is among the best available options for genetic screening, providing several benefits that include enhanced sensitivity and unbiased mutation detection. PALB2 (partner and localizer of BRCA2) is a cancer predisposing gene recently described that encodes a protein partner of BRCA2 involved in DNA double‐strand break repair and cell cycle control. The DNA damage response represents a key cellular event, targeted by innovative anticancer therapies, including those based on poly (ADP‐ribose) polymerase (PARP) inhibitors targeting PARP1 and PARP2 enzymes, activated by DNA damage and involved in single‐strand break and base excision repair.

Allelic Complexity in Long QT Syndrome: A Family-Case Study

Congenital long QT syndrome (LQTS) is associated with high genetic and allelic heterogeneity. In some cases, more than one genetic variant is identified in the same (compound heterozygosity) or different (digenic heterozygosity) genes, and subjects with multiple pathogenic mutations may have a more severe disease. Standard-of-care clinical genetic testing for this and other arrhythmia susceptibility syndromes improves the identification of complex genotypes. Therefore, it is important to distinguish between pathogenic mutations and benign rare variants. We identified four genetic variants (KCNQ1-p.R583H, KCNH2-p.C108Y, KCNH2-p.K897T, and KCNE1-p.G38S) in an LQTS family. On the basis of in silico analysis, clinical data from our family, and the evidence from previous studies, we analyzed two mutated channels, KCNQ1-p.R583H and KCNH2-p.C108Y, using the whole-cell patch clamp technique. We found that KCNQ1-p.R583H was not associated with a severe functional impairment, whereas KCNH2-p.C108Y, a novel variant, encoded a non-functional channel that exerts dominant-negative effects on the wild-type. Notably, the common variants KCNH2-p.K897T and KCNE1-p.G38S were previously reported to produce more severe phenotypes when combined with disease-causing alleles. Our results indicate that the novel KCNH2-C108Y variant can be a pathogenic LQTS mutation, whereas KCNQ1-p.R583H, KCNH2-p.K897T, and KCNE1-p.G38S could be LQTS modifiers.