Publications by authors named "Elena Andreucci"

48 Publications

uPAR controls vasculogenic mimicry ability expressed by drug-resistant melanoma cells.

Oncol Res 2021 Jul 27. Epub 2021 Jul 27.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134, Florence, Italy.

Malignant melanoma is a highly aggressive skin cancer characterized by an elevated grade of tumor cell plasticity. Such plasticity allows melanoma cells adaptation to different hostile conditions and guarantees tumor survival and disease progression, including aggressive features such as drug resistance. Indeed, almost 50% of melanoma rapidly develop resistance to the BRAFV600E inhibitor vemurafenib, with fast tumor dissemination, a devastating consequence for patients' outcomes. Vasculogenic mimicry (VM), the ability of cancer cells to organize themselves in perfused vascular-like channels, might sustain tumor spread by providing vemurafenib-resistant cancer cells with supplementary ways to enter into circulation and disseminate. Thus, this research aims to determine if vemurafenib resistance goes with the acquisition of VM ability by aggressive melanoma cells, and identify a driving molecule for both vemurafenib resistance and VM. We used two independent experimental models of drug-resistant melanoma cells, the first one represented by a chronic adaptation of melanoma cells to extracellular acidosis, known to drive a particularly aggressive and vemurafenib-resistant phenotype, the second one generated with chronic vemurafenib exposure. By performing in vitro tube formation assay and evaluating the expression levels of the VM markers EphA2 and VE-cadherin by western blotting and flow cytometer analyses, we demonstrated that vemurafenib-resistant cells obtained by both models are characterized by an increased ability to perform VM. Moreover, by exploiting the CRISPR-Cas9 technique and using the urokinase plasminogen activator receptor (uPAR) inhibitor M25, we identified uPAR as a driver of VM expressed by vemurafenib-resistant melanoma cells. Thus, uPAR targeting may be successfully leveraged as a new complementary therapy to inhibit VM in drug-resistant melanoma patients, to counteract the rapid progression and dissemination of the disease.
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http://dx.doi.org/10.3727/096504021X16273798026651DOI Listing
July 2021

Enhanced Vasculogenic Capacity Induced by 5-Fluorouracil Chemoresistance in a Gastric Cancer Cell Line.

Int J Mol Sci 2021 Jul 19;22(14). Epub 2021 Jul 19.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale G.B. Morgagni, 50-50134 Firenze, Italy.

Chemotherapy is still widely used as a coadjutant in gastric cancer when surgery is not possible or in presence of metastasis. During tumor evolution, gatekeeper mutations provide a selective growth advantage to a subpopulation of cancer cells that become resistant to chemotherapy. When this phenomenon happens, patients experience tumor recurrence and treatment failure. Even if many chemoresistance mechanisms are known, such as expression of ATP-binding cassette (ABC) transporters, aldehyde dehydrogenase (ALDH1) activity and activation of peculiar intracellular signaling pathways, a common and universal marker for chemoresistant cancer cells has not been identified yet. In this study we subjected the gastric cancer cell line AGS to chronic exposure of 5-fluorouracil, cisplatin or paclitaxel, thus selecting cell subpopulations showing resistance to the different drugs. Such cells showed biological changes; among them, we observed that the acquired chemoresistance to 5-fluorouracil induced an endothelial-like phenotype and increased the capacity to form vessel-like structures. We identified the upregulation of thymidine phosphorylase (TYMP), which is one of the most commonly reported mutated genes leading to 5-fluorouracil resistance, as the cause of such enhanced vasculogenic ability.
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http://dx.doi.org/10.3390/ijms22147698DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8303918PMC
July 2021

CRISPR/Cas9 uPAR Gene Knockout Results in Tumor Growth Inhibition, EGFR Downregulation and Induction of Stemness Markers in Melanoma and Colon Carcinoma Cell Lines.

Front Oncol 2021 14;11:663225. Epub 2021 May 14.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Firenze, Italy.

uPAR is a globular protein, tethered to the cell membrane by a GPI-anchor involved in several cancer-related properties and its overexpression commonly correlates with poor prognosis and metastasis. We investigated the consequences of uPAR irreversible loss in human melanoma and colon cancer cell lines, knocking out its expression by CRISPR/Cas9. We analyzed through flow cytometry, western blotting and qPCR, the modulation of the most known cancer stem cells-associated genes and the EGFR while we observed the proliferation rate exploiting 2D and 3D cellular models. We also generated uPAR "rescue" expression cell lines as well as we promoted the expression of only its 3'UTR to demonstrate the involvement of uPAR mRNA in tumor progression. Knocking out PLAUR, uPAR-encoding gene, we observed an inhibited growth ratio unexpectedly coupled with a significant percentage of cells acquiring a stem-like phenotype. experiments demonstrated that uPAR loss completely abrogates tumorigenesis despite the gained stem-like profile. Nonetheless, we proved that the reintroduction of the 3'UTR of PLAUR gene was sufficient to restore the wild-type status validating the hypothesis that such a region may act as a "molecular sponge". In particular miR146a, by binding PLAUR 3' UTR region might be responsible for uPAR-dependent inhibition of EGFR expression.
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http://dx.doi.org/10.3389/fonc.2021.663225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8163229PMC
May 2021

Mosaic Segmental and Whole-Chromosome Upd(11)mat in Silver-Russell Syndrome.

Genes (Basel) 2021 04 16;12(4). Epub 2021 Apr 16.

Department of Environmental Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), Università degli Studi della Campania "Luigi Vanvitelli", 81100 Caserta, Italy.

Molecular defects altering the expression of the imprinted genes of the 11p15.5 cluster are responsible for the etiology of two congenital disorders characterized by opposite growth disturbances, Silver-Russell syndrome (SRS), associated with growth restriction, and Beckwith-Wiedemann syndrome (BWS), associated with overgrowth. At the molecular level, SRS and BWS are characterized by defects of opposite sign, including loss (LoM) or gain (GoM) of methylation at the :intergenic differentially methylated region (:IG-DMR), maternal or paternal duplication (dup) of 11p15.5, maternal (mat) or paternal (pat) uniparental disomy (upd), and gain or loss of function mutations of . However, while upd(11)pat is found in 20% of BWS cases and in the majority of them it is segmental, upd(11)mat is extremely rare, being reported in only two SRS cases to date, and in both of them is extended to the whole chromosome. Here, we report on two novel cases of mosaic upd(11)mat with SRS phenotype. The upd is mosaic and isodisomic in both cases but covers the entire chromosome in one case and is restricted to 11p14.1-pter in the other case. The segmental upd(11)mat adds further to the list of molecular defects of opposite sign in SRS and BWS, making these two imprinting disorders even more specular than previously described.
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http://dx.doi.org/10.3390/genes12040581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8073375PMC
April 2021

When to test fetuses for RASopathies? Proposition from a systematic analysis of 352 multicenter cases and a postnatal cohort.

Genet Med 2021 06 10;23(6):1116-1124. Epub 2021 Feb 10.

Pediatrics Department, Medical Genetics Division, CHU Sainte-Justine, Montreal, QC, Canada.

Purpose: Recent studies have identified suggestive prenatal features of RASopathies (e.g., increased nuchal translucency [NT], cystic hygroma [CH], hydrops, effusions, congenital heart diseases [CHD], polyhydramnios, renal anomalies). Our objective is to clarify indications for RASopathy prenatal testing. We compare genotype distributions between pre- and postnatal populations and propose genotype-phenotype correlations.

Methods: Three hundred fifty-two chromosomal microarray-negative cases sent for prenatal RASopathy testing between 2012 and 2019 were collected. For most, 11 RASopathy genes were tested. Postnatal cohorts (25 patients with available prenatal information and 108 institutional database genotypes) and the NSeuroNet database were used for genotypic comparisons.

Results: The overall diagnostic yield was 14% (50/352), with rates >20% for effusions, hydrops, and CHD. Diagnostic yield was significantly improved in presence of hypertrophic cardiomyopathy (HCM), persistent or associated CH, any suggestive finding combined with renal anomaly or polyhydramnios, or ≥2 ultrasound findings. Largest prenatal contributors of pathogenic variants were PTPN11 (30%), RIT1 (16%), RAF1 (14%), and HRAS (12%), which considerably differ from their prevalence in postnatal populations. HRAS, LZTR1, and RAF1 variants correlated with hydrops/effusions, and RIT1 with prenatal onset HCM.

Conclusion: After normal chromosomal microarray, RASopathies should be considered when any ultrasound finding of lymphatic dysplasia or suggestive CHD is found alone or in association.
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http://dx.doi.org/10.1038/s41436-020-01093-7DOI Listing
June 2021

Glycolysis-derived acidic microenvironment as a driver of endothelial dysfunction in systemic sclerosis.

Rheumatology (Oxford) 2021 Jan 20. Epub 2021 Jan 20.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology, University of Florence, Florence, Italy.

Objectives: Systemic sclerosis (SSc) is an autoimmune disease characterized by peripheral vasculopathy and skin and internal organ fibrosis. Accumulating evidence underlines a close association between a metabolic reprogramming of activated fibroblasts and fibrosis. This prompted us to determine the metabolism of SSc dermal fibroblasts and the effect on the vasculopathy characterizing the disease.

Methods: Seahorse XF96 Extracellular Flux Analyzer was exploited to evaluate SSc fibroblast metabolism. In vitro invasion and capillary morphogenesis assays were used to determine the angiogenic ability of endothelial cells (EC). Immunofluorescence, flow cytometer and real time PCR techniques provided evidence of the molecular mechanism behind the impaired vascularization that characterizes SSc patients.

Results: SSc fibroblasts, compared with control, showed a boosted glycolytic metabolism with increased lactic acid release and subsequent extracellular acidification, that in turn was found to impair EC invasion and organization in capillary-like networks without altering cell viability. A molecular link between extracellular acidosis and endothelial dysfunction was identified as acidic EC up-regulated MMP-12 which cleaves and inactivates uPAR, impairing angiogenesis in SSc. Moreover, the acidic environment was found to induce the loss of endothelial markers and the acquisition of mesenchymal-like features in EC, thus promoting the endothelial-to-mesenchymal transition (EndoMT) process that contributes to both capillary rarefaction and tissue fibrosis in SSc.

Conclusion: This study disclosed a liaison among the metabolic reprogramming of SSc dermal fibroblasts, extracellular acidosis and endothelial dysfunction that may contribute to the impairment and loss of peripheral capillary networks in SSc disease.
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http://dx.doi.org/10.1093/rheumatology/keab022DOI Listing
January 2021

uPAR-expressing melanoma exosomes promote angiogenesis by VE-Cadherin, EGFR and uPAR overexpression and rise of ERK1,2 signaling in endothelial cells.

Cell Mol Life Sci 2021 Mar 25;78(6):3057-3072. Epub 2020 Nov 25.

Department of Experimental and Clinical Biomedical Sciences, Section of Experimental Pathology and Oncology, University of Florence, Viale G.B. Morgagni, 50, 50134, Florence, Italy.

Exosomes (Exos) have been reported to promote pre-metastatic niche formation, proliferation, angiogenesis and metastasis. We have investigated the role of uPAR in melanoma cell lines-derived Exos and their pro-angiogenic effects on human microvascular endothelial cells (HMVECs) and endothelial colony-forming cells (ECFCs). Melanoma Exos were isolated from conditioned media of A375 and M6 cells by differential centrifugation and filtration. Tunable Resistive Pulse Sensing (TRPS) and Nanoparticle tracking analysis were performed to analyze dimension and concentration of Exos. The CRISPR-Cas 9 technology was exploited to obtain a robust uPAR knockout. uPAR is expressed in melanoma Exos that are internalized by HMVECs and ECFCs, enhancing VE-Cadherin, EGFR and uPAR expression in endothelial cells that undergo a complete angiogenic program, including proliferation, migration and tube formation. uPAR loss reduced the pro-angiogenic effects of melanoma Exos in vitro and in vivo by inhibition of VE-Cadherin, EGFR and uPAR expression and of ERK1,2 signaling in endothelial cells. A similar effect was obtained with a peptide that inhibits uPAR-EGFR interaction and with the EGFR inhibitor Gefitinib, which also inhibited melanoma Exos-dependent EGFR phosphorylation. This study suggests that uPAR is required for the pro-angiogenic activity of melanoma Exos. We propose the identification of uPAR-expressing Exos as a potentially useful biomarker for assessing pro-angiogenic propensity and eventually monitoring the response to treatment in metastatic melanoma patients.
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http://dx.doi.org/10.1007/s00018-020-03707-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8004497PMC
March 2021

Expanding the phenotype of Wiedemann-Steiner syndrome: Craniovertebral junction anomalies.

Am J Med Genet A 2020 12 11;182(12):2877-2886. Epub 2020 Oct 11.

Medical Genetics Unit, Meyer Children's University Hospital, Florence, Italy.

Wiedemann-Steiner syndrome (WDSTS) is a rare autosomal dominant condition caused by heterozygous loss of function variants in the KMT2A (MLL) gene, encoding a lysine N-methyltransferase that mediates a histone methylation pattern specific for epigenetic transcriptional activation. WDSTS is characterized by a distinctive facial phenotype, hypertrichosis, short stature, developmental delay, intellectual disability, congenital malformations, and skeletal anomalies. Recently, a few patients have been reported having abnormal skeletal development of the cervical spine. Here we describe 11 such individuals, all with KMT2A de novo loss-of-function variants: 10 showed craniovertebral junction anomalies, while an 11th patient had a cervical abnormality in C7. By evaluating clinical and diagnostic imaging data we characterized these anomalies, which consist primarily of fused cervical vertebrae, C1 and C2 abnormalities, small foramen magnum and Chiari malformation type I. Craniovertebral anomalies in WDSTS patients have been largely disregarded so far, but the increasing number of reports suggests that they may be an intrinsic feature of this syndrome. Specific investigation strategies should be considered for early identification and prevention of craniovertebral junction complications in WDSTS patients.
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http://dx.doi.org/10.1002/ajmg.a.61859DOI Listing
December 2020

The acidic tumor microenvironment drives a stem-like phenotype in melanoma cells.

J Mol Med (Berl) 2020 10 15;98(10):1431-1446. Epub 2020 Aug 15.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology, University of Florence, Florence, Italy.

Acidosis characterizes the microenvironment of most solid tumors and is considered a new hallmark of cancer. It is mainly caused by both "aerobic" and "anaerobic" glycolysis of differently adapted cancer cells, with the final product lactic acid being responsible of the extracellular acidification. Many evidences underline the role of extracellular acidosis in tumor progression. Among the different findings, we demonstrated that acidosis-exposed cancer cells are characterized by an epithelial-to-mesenchymal transition phenotype with high invasive ability, high resistance to apoptosis, anchorage-independent growth, and drug therapy. Acidic melanoma cells over-express SOX2, which is crucial for the maintenance of their oxidative metabolism, and carbonic anhydrase IX, that correlates with poor prognosis of cancer patients. Considering these evidences, we realized that the profile outlined for acid cancer cells inevitably remind us the stemness profile. Therefore, we wondered whether extracellular acidosis might induce in cancer cells the acquisition of stem-like properties and contribute to the expansion of the cancer stem cell sub-population. We found that a chronic adaptation to acidosis stimulates in cancer cells the expression of stem-related markers, also providing a high in vitro/in vivo clonogenic and trans-differentiating ability. Moreover, we observed that the acidosis-induced stem-like phenotype of melanoma cells was reversible and related to the EMT induction. These findings help to characterize a further aspect of stem cell niche, contributing to the sustainment and expansion of cancer stem cell subpopulation. Thus, the usage of agents controlling tumor extracellular acidosis might acquire great importance in the clinic for the treatment of aggressive solid tumor. KEY MESSAGES: • Extracellular acidosis up-regulates EMT and stem-related markers in melanoma cells • Acidic medium up-regulates in vitro self-renewal capacity of melanoma cells • Chronic acidosis adaptation induces trans-differentiation ability in melanoma cells • Melanoma cells adapted to acidosis show higher tumor-initiating potential than control cells • Extracellular acidosis promotes a stem-like phenotype in prostate and colorectal carcinoma cells.
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http://dx.doi.org/10.1007/s00109-020-01959-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7525286PMC
October 2020

Variants of SOS2 are a rare cause of Noonan syndrome with particular predisposition for lymphatic complications.

Eur J Hum Genet 2021 Jan 12;29(1):51-60. Epub 2020 Aug 12.

Institute of Human Genetics, University Hospital Magdeburg, Magdeburg, Germany.

RASopathies are caused by variants in genes encoding components or modulators of the RAS/MAPK signaling pathway. Noonan syndrome is the most common entity among this group of disorders and is characterized by heart defects, short stature, variable developmental delay, and typical facial features. Heterozygous variants in SOS2, encoding a guanine nucleotide exchange factor for RAS, have recently been identified in patients with Noonan syndrome. The number of published cases with SOS2-related Noonan syndrome is still limited and little is known about genotype-phenotype correlations. We collected previously unpublished clinical and genotype data from 17 individuals carrying a disease-causing SOS2 variant. Most individuals had one of the previously reported dominant pathogenic variants; only four had novel changes at the established hotspots for variants that affect protein function. The overall phenotype of the 17 patients fits well into the spectrum of Noonan syndrome and is most similar to the phenotype observed in patients with SOS1-related Noonan syndrome, with ectodermal anomalies as common features and short stature and learning disabilities as relatively infrequent findings compared to the average Noonan syndrome phenotype. The spectrum of heart defects in SOS2-related Noonan syndrome was consistent with the known spectrum of cardiac anomalies in RASopathies, but no specific heart defect was particularly predominating. Notably, lymphatic anomalies were extraordinarily frequent, affecting more than half of the patients. We therefore conclude that SOS2-related Noonan syndrome is associated with a particularly high risk of lymphatic complications that may have a significant impact on morbidity and quality of life.
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http://dx.doi.org/10.1038/s41431-020-00708-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7852574PMC
January 2021

The Carbonic Anhydrase IX inhibitor SLC-0111 as emerging agent against the mesenchymal stem cell-derived pro-survival effects on melanoma cells.

J Enzyme Inhib Med Chem 2020 Dec;35(1):1185-1193

Department of Clinical and Experimental Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology, University of Florence, Florence, Italy.

Mesenchymal stem cells (MSC) take part to solid tumour-associated stroma and critically influence progression of malignancy. Our study represents a striking example of melanoma progression to a more malignant and resistant phenotype promoted by MSC and the possibility to contrast this diabolic liaison using CAIX inhibitors. In particular, we demonstrated that melanoma cells exposed to a MSC-conditioned medium switch to a more malignant phenotype, characterised by resistance to programmed cell death and endowed with an epithelial-to-mesenchymal transition and stem cell characteristics. These effects were reversed abrogating MSC CAIX activity using SLC-0111, a CAIX inhibitor. Moreover, the acquisition by melanoma cells of a Vemurafenib-resistant phenotype upon MSC-conditioned medium exposure was removed when MSC were treated with SLC-0111. Therefore, MSC may profoundly reprogramme melanoma cells towards a wide resistant phenotype through CAIX involvement, as the use of SLC-0111 is able to contrast the development of this highly risky adaptation for disease progression.
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http://dx.doi.org/10.1080/14756366.2020.1764549DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269050PMC
December 2020

FDG uptake in cancer: a continuing debate.

Theranostics 2020 6;10(7):2944-2948. Epub 2020 Feb 6.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology.

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http://dx.doi.org/10.7150/thno.40599DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7053207PMC
March 2021

Cancer Glycolytic Dependence as a New Target of Olive Leaf Extract.

Cancers (Basel) 2020 Jan 29;12(2). Epub 2020 Jan 29.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134 Florence, Italy.

Oleuropein (Ole), the main bioactive phenolic component of L. has recently attracted the scientific attention for its several beneficial properties, including its anticancer effects. This study is intended to investigate whether an olive leaf extract enriched in Ole (OLEO) may counteract the aerobic glycolysis exploited by tumor cells. We found that OLEO decreased melanoma cell proliferation and motility. OLEO was also able to reduce the rate of glycolysis of human melanoma cells without affecting oxidative phosphorylation. This reduction was associated with a significant decrease of glucose transporter-1, protein kinase isoform M2 and monocarboxylate transporter-4 expression, possible drivers of such glycolysis inhibition. Extending the study to other tumor histotypes, we observed that the metabolic effects of OLEO are not confined to melanoma, but also confirmed in colon carcinoma, breast cancer and chronic myeloid leukemia. In conclusion, OLEO represents a natural product effective in reducing the glycolytic metabolism of different tumor types, revealing an extended metabolic inhibitory activity that may be well suited in a complementary anti-cancer therapy.
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http://dx.doi.org/10.3390/cancers12020317DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072393PMC
January 2020

uPAR Knockout Results in a Deep Glycolytic and OXPHOS Reprogramming in Melanoma and Colon Carcinoma Cell Lines.

Cells 2020 01 28;9(2). Epub 2020 Jan 28.

Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale G.B. Morgagni 50, 50134 Firenze, Italy.

Urokinase Plasminogen Activator (uPA) Receptor (uPAR) is a well-known GPI-anchored three-domain membrane protein with pro-tumor roles largely shown in all the malignant tumors where it is over-expressed. Here we have exploited the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 gene knock out approach to investigate its role in the oxidative metabolism in human melanoma and colon cancer as the consequences of its irreversible loss. Knocking out , a uPAR-encoding gene, in A375p, A375M6 and HCT116, which are two human melanoma and a colon carcinoma, respectively, we have observed an increased number of mitochondria in the two melanoma cell lines, while we evidenced an immature biogenesis of mitochondria in the colon carcinoma culture. Such biological diversity is, however, reflected in a significant enhancement of the mitochondrial spare respiratory capacity, fueled by an increased expression of GLS2, and in a decreased glycolysis paired with an increased secretion of lactate by all uPAR KO cells. We speculated that this discrepancy might be explained by an impaired ratio between LDHA and LDHB.
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http://dx.doi.org/10.3390/cells9020308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072355PMC
January 2020

A potentiated cooperation of carbonic anhydrase IX and histone deacetylase inhibitors against cancer.

J Enzyme Inhib Med Chem 2020 Dec;35(1):391-397

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy.

The emergence of tumour recurrence and resistance limits the survival rate for most tumour-bearing patients. Only, combination therapies targeting pathways involved in the induction and in the maintenance of cancer growth and progression might potentially result in an enhanced therapeutic efficacy. Herein, we provided a prospective combination treatment that includes suberoylanilide hydroxamic acid (SAHA), a well-known inhibitor of histone deacetylases (HDACs), and SLC-0111, a novel inhibitor of carbonic anhydrase (CA) IX. We proved that HDAC inhibition with SAHA in combination with SLC-0111 affects cell viability and colony forming capability to greater extent than either treatment alone of breast, colorectal and melanoma cancer cells. At the molecular level, this therapeutic regimen resulted in a synergistically increase of histone H4 and p53 acetylation in all tested cell lines. Overall, our findings showed that SAHA and SLC-0111 can be regarded as very attractive combination providing a potential therapeutic strategy against different cancer models.
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http://dx.doi.org/10.1080/14756366.2019.1706090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6968260PMC
December 2020

Potential Role of HLA Class I Antigens in the Glycolytic Metabolism and Motility of Melanoma Cells.

Cancers (Basel) 2019 Aug 26;11(9). Epub 2019 Aug 26.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology, Viale G.B. Morgagni, 50-50134, Florence, Italy.

Besides playing a crucial role in immune surveillance, human leukocyte antigens (HLA) possess numerous non-immune functions involved in cell communication. In the present study, screening of a panel of HLA class I- and HLA class II-specific monoclonal antibodies (mAbs) for their effects on the metabolism of human melanoma cells showed for the first time that the HLA-B,C-specific mAb B1.23.2 reduced the expression level of key glycolytic enzymes, but did not affect that of mitochondrial respiration effectors. As a result, the metabolism of melanoma cells shifted from a Warburg metabolism to a more oxidative phosphorylation. In addition, the HLA-B,C-specific mAb B1.23.2 downregulated the expression of glutamine transporter and glutaminase enzyme participating in the reduction of tricarboxylic acid cycle. The HLA-B,C-specific mAb B1.23.2-mediated reduction in energy production was associated with a reduction of melanoma cell motility. On the whole, the described results suggest that HLA class I antigens, and in particular the gene products of HLA-B and C loci play a role in the motility of melanoma cells by regulating their metabolism.
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http://dx.doi.org/10.3390/cancers11091249DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770395PMC
August 2019

Anoikis Resistance as a Further Trait of Acidic-Adapted Melanoma Cells.

J Oncol 2019 2;2019:8340926. Epub 2019 Jun 2.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio," Section of Experimental Pathology and Oncology, Italy.

Melanoma is characterized by a low extracellular pH, which contributes to the development of an aggressive phenotype characterized by several properties as the switch to an epithelial-to-mesenchymal program, the increase of apoptotic resistance, and the migratory ability together with the development of drug resistance. Here, we demonstrate that melanoma cells grown in low pH medium (pH 6.7) for a short (24 hours) or long (at least 3 months) period equally express an anoikis resistance profile. Anoikis is a form of apoptosis prompted by loss of adhesion, particularly requested by aggressive cancer cells to metastasize. Anoikis resistance was ascertained in acidic melanoma cells either grown in agarose-coated plates or incubated in rocking conditions. Both analyses indicate that acidic cells were more able to survive in a nonadherent condition than cells grown in standard pH, an effect resulting in a more cloning efficiency and migratory ability. Ability to survive during rocking was inhibited using mTOR/NF-kB inhibitors. Finally, we checked whether characteristics related to the anoikis resistance acquired by acidic melanoma cells might be also suitable for challenge. We injected acidic melanoma cells into blood stream, and then we verify how many cells survived in blood after 15 min from the injection. Only acidic cells, transient and chronic, survived, whereas melanoma cells grown in standard pH medium did not. Overall, we have had the opportunity to demonstrate that low extracellular pH represents an additional mechanism able to promote an anoikis resistance in solid tumors.
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http://dx.doi.org/10.1155/2019/8340926DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6582804PMC
June 2019

Cell-targeted c(AmpRGD)-sunitinib molecular conjugates impair tumor growth of melanoma.

Cancer Lett 2019 04 11;446:25-37. Epub 2019 Jan 11.

Food and Drug Department, University of Parma, Parco Area delle Scienze 27A, 43124, Parma, Italy. Electronic address:

Drug resistance and off-organ toxicity remain unsolved issues in chemotherapy of advanced-stage melanoma patients. Thus, the creation of new molecular conjugates able to combine a selective accumulation, high ability of internalization and signaling pathway inhibition, are highly requested. Recently, we reported a new class of molecular conjugates, compounds 1-3, where the anti-αβ integrin peptidomimetic c(AmpRGD), which is a selective ligand for αβ integrin, was covalently bound to the tyrosine kinase inhibitor sunitinib. Here, we report that these c(AmpRGD)-sunitinib conjugates and, in particular, compound 3, are selectively internalized by human melanoma cells through αβ receptor-mediated endocytosis. Compound 3 is more effective than sunitinib in reducing in vitro melanoma cells proliferation, cloning efficiency, migration, and invasion. More interestingly, compound 3 is able to significantly reduce the growth of xenografted melanoma tumor developed in immune-compromised mice, more efficiently than an equimolar dose of sunitinib. Indeed, its targeting ability was demonstrated by the selective localization at the tumor level with respect to healthy tissues. Thus, c(AmpRGD)-sunitinib conjugates such as compound 3 could serve as intriguing multiple-target agents to selectively reach melanoma cells and interfere with the progression of the disease.
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http://dx.doi.org/10.1016/j.canlet.2018.12.021DOI Listing
April 2019

EGFR/uPAR interaction as druggable target to overcome vemurafenib acquired resistance in melanoma cells.

EBioMedicine 2019 Jan 2;39:194-206. Epub 2019 Jan 2.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale G.B. Morgagni, 50, 50134 Florence, Italy.

Background: BRAF inhibitor (BRAF-I) therapy for melanoma patients harboring the V600E mutation is initially highly effective, but almost all patients relapse within a few months. Understanding the molecular mechanisms behind BRAF-I responsiveness and acquired resistance is therefore an important issue. Here we assessed the role of urokinase type plasminogen activator receptor (uPAR) as a potentially valuable biomarker in the acquisition of BRAF-I resistance in V600E mutant melanoma cells.

Methods: We examined uPAR and EGFR levels by real time PCR and western blot analysis. uPAR loss of function was realized by knocking down uPAR by RNAi or using M25, a peptide that uncouples uPAR-integrin interaction. We investigated uPAR-β1integrin-EGFR association by co-immunoprecipitation and confocal immuno-fluorescence analysis. Acquired resistance to BRAF-I was generated by chronic exposure of cells to vemurafenib.

Findings: We proved that uPAR knockdown in combination with vemurafenib inhibits melanoma cell proliferation to greater extent than either treatment alone causing a decrease in AKT and ERK1/2 phosphorylation. Conversely, we demonstrated that uPAR enforced over-expression results in reduced sensitivity to BRAF inhibition. Moreover, by targeting uPAR and EGFR interaction with an integrin antagonist peptide we restored vemurafenib responsiveness in melanoma resistant cells. Furthermore, we found significant detectable uPAR and EGFR levels in tumor biopsies of 4 relapsed patients.

Interpretation: We disclosed an unpredicted mechanism of reduced sensitiveness to BRAF inhibition, driven by elevated levels of uPAR and identified a potential therapeutic strategy to overcome acquired resistance.

Funds: Associazione Italiana Ricerca sul Cancro (AIRC); Ente Cassa di Risparmio di Firenze.
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http://dx.doi.org/10.1016/j.ebiom.2018.12.024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6355443PMC
January 2019

Oleuropein, the Main Polyphenol of Leaf Extract, Has an Anti-Cancer Effect on Human BRAF Melanoma Cells and Potentiates the Cytotoxicity of Current Chemotherapies.

Nutrients 2018 Dec 8;10(12). Epub 2018 Dec 8.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, 50134 Florence, Italy.

Oleuropein (Ole), a secoiridoid glucoside present in leaves, gained scientific interest thanks to its several biological properties, including the anticancer one. We verified whether Ole might potentiate the cytotoxicity of conventional drugs used to treat melanoma, disclosing a potentially new therapeutic strategy. We tested the cytotoxic action of Ole alone or in combination with chemotherapeutics on A375 human melanoma cells. We found that Ole was able, at a dose of 500 µM, to stimulate apoptosis, while at a non-toxic dose of 250 µM, it affected cell proliferation and induced the downregulation of the pAKT/pS6 pathway. A dose of 250 µM Ole did not potentiate the effect of Vemurafenib (PLX4032), but it succeeded in increasing the cytotoxic effect of Dacarbazine (DTIC). The major effect was found in the association between Ole and Everolimus (RAD001), also on PLX4032-resistant BRAF melanoma cells, which possibly cooperate in the inhibition of the pAKT/pS6 pathway. Of interest, an olive leaf extract enriched in equimolar Ole was more effective and able to further improve DTIC and RAD001 efficacy on BRAF melanoma cells with respect to Ole alone. Therefore, Ole represents a natural product able to potentiate a wide array of chemotherapeutics against BRAF melanoma cells affecting the pAKT/pS6 pathway.
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http://dx.doi.org/10.3390/nu10121950DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316801PMC
December 2018

SOX2 as a novel contributor of oxidative metabolism in melanoma cells.

Cell Commun Signal 2018 11 22;16(1):87. Epub 2018 Nov 22.

Department of Clinical and Experimental Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology, University of Florence, Viale G.B. Morgagni, 50, 50134, Florence, Italy.

Background: Deregulated metabolism is a hallmark of cancer and recent evidence underlines that targeting tumor energetics may improve therapy response and patient outcome. Despite the general attitude of cancer cells to exploit the glycolytic pathway even in the presence of oxygen (aerobic glycolysis or "Warburg effect"), tumor metabolism is extremely plastic, and such ability to switch from glycolysis to oxidative phosphorylation (OxPhos) allows cancer cells to survive under hostile microenvironments. Recently, OxPhos has been related with malignant progression, chemo-resistance and metastasis. OxPhos is induced under extracellular acidosis, a well-known characteristic of most solid tumors, included melanoma.

Methods: To evaluate whether SOX2 modulation is correlated with metabolic changes under standard or acidic conditions, SOX2 was silenced and overexpressed in several melanoma cell lines. To demonstrate that SOX2 directly represses HIF1A expression we used chromatin immunoprecipitation (ChIP) and luciferase assay.

Results: In A375-M6 melanoma cells, extracellular acidosis increases SOX2 expression, that sustains the oxidative cancer metabolism exploited under acidic conditions. By studying non-acidic SSM2c and 501-Mel melanoma cells (high- and very low-SOX2 expressing cells, respectively), we confirmed the metabolic role of SOX2, attributing SOX2-driven OxPhos reprogramming to HIF1α pathway disruption.

Conclusions: SOX2 contributes to the acquisition of an aggressive oxidative tumor phenotype, endowed with enhanced drug resistance and metastatic ability.
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http://dx.doi.org/10.1186/s12964-018-0297-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6249961PMC
November 2018

The carbonic anhydrase IX inhibitor SLC-0111 sensitises cancer cells to conventional chemotherapy.

J Enzyme Inhib Med Chem 2019 Dec;34(1):117-123

a Department of Clinical and Experimental Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology , University of Florence , Florence , Italy.

Drug combination represents one of the most accredited strategies of cancer therapy able to improve drug efficacy and possibly overcome drug resistance. Among the agents used to complement conventional chemotherapy, carbonic anhydrase IX (CAIX) inhibitors appear as one of the most suitable, as markers of hypoxic and acidic cancer cells which do not respond to chemo- and radiotherapy. We performed preclinical in vitro assays to evaluate whether the SLC-0111 CAIX inhibitor co-operates and potentiates the cytotoxic effects of conventional chemotherapeutic drugs in A375-M6 melanoma cells, MCF7 breast cancer cells, and HCT116 colorectal cancer cells. Here, we demonstrate that the SLC-0111 CAIX inhibitor potentiates cytotoxicity of Dacarbazine and Temozolomide currently used for advanced melanoma treatment. SLC-0111 also increases breast cancer cell response to Doxorubicin and enhances 5-Fluorouracil cytostatic activity on colon cancer cells. These findings disclose the possibility to extend the use of CAIX inhibitors in the combination therapy of various cancer histotypes.
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http://dx.doi.org/10.1080/14756366.2018.1532419DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211231PMC
December 2019

Carbonic anhydrase IX inhibition affects viability of cancer cells adapted to extracellular acidosis.

J Mol Med (Berl) 2017 12 19;95(12):1341-1353. Epub 2017 Sep 19.

Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy.

Among the players of the adaptive response of cancer cells able to promote a resistant and aggressive phenotype, carbonic anhydrase IX (CAIX) recently has emerged as one of the most relevant drug targets. Indeed, CAIX targeting has received a lot of interest, and selective inhibitors are currently under clinical trials. Hypoxia has been identified as the master inductor of CAIX, but, to date, very few is known about the influence that another important characteristic of tumor microenvironment, i.e., extracellular acidosis, exerts on CAIX expression and activity. In the last decades, acidic microenvironment has been associated with aggressive tumor phenotype endowed with epithelial-to-mesenchymal transition (EMT) profile, high invasive and migratory ability, apoptosis, and drug resistance. We demonstrated that melanoma, breast, and colorectal cancer cells transiently and chronically exposed to acidified medium (pH 6.7 ± 0.1) showed a significantly increased CAIX expression compared to those grown in standard conditions (pH 7.4 ± 0.1). Moreover, we observed that the CAIX inhibitor FC16-670A (also named SLC-0111, which just successfully ended phase I clinical trials) not only prevents such increased expression under acidosis but also promotes apoptotic and necrotic programs only in acidified cancer cells. Thus, CAIX could represent a selective target of acidic cancer cells and FC16-670A inhibitor as a useful tool to affect this aggressive subpopulation characterized by conventional therapy escape.

Key Messages: Cancer cells overexpress CAIX under transient and chronic extracellular acidosis. Acidosis-induced CAIX overexpression is NF-κB mediated and HIF-1α independent. FC16-670A prevents CAIX overexpression and induces acidified cancer cell death.
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http://dx.doi.org/10.1007/s00109-017-1590-9DOI Listing
December 2017

Everolimus selectively targets vemurafenib resistant BRAF melanoma cells adapted to low pH.

Cancer Lett 2017 11 18;408:43-54. Epub 2017 Aug 18.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Experimental Pathology and Oncology, University of Florence, Italy; Istituto Toscano Tumori, Center of Excellence for the Study at Molecular and Clinical Level of Chronic, Degenerative and Neoplastic Diseases to Develop Novel Therapies (DENOTHE), Italy. Electronic address:

Vemurafenib, a BRAF inhibitor, elicits in ∼80% of BRAF-mutant melanoma patients a transient anti-tumor response which precedes the emergence of resistance. We tested whether an acidic tumor microenvironment may favor a BRAF inhibitor resistance. A375M6 BRAF melanoma cells, either exposed for a short period or chronically adapted to an acidic medium, showed traits compatible with an epithelial-mesenchymal transition, reduced proliferation and high resistance to apoptosis. Both types of acidic cells treated with vemurafenib did not change their proliferation, distribution in cell cycle and level of p-AKT, in contrast to cells grown at standard pH, which showed reduced proliferation, cell cycle arrest and ERK/AKT inhibition. Even after treatment with trametinib (MEK inhibitor) acidic cell features did not change. Then, since both types of acidic cells exhibited high p-p70S6K, i.e. active mTOR signaling, we tested everolimus, an mTOR inhibitor, which was efficient in inducing apoptosis in acidic cells without affecting melanoma cells grown at standard pH. Our results indicate that an acidic microenvironment may cooperate in inducing a BRAF inhibitor resistance in melanoma cells and a combined therapy with everolimus could be used to overcome that resistance.
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http://dx.doi.org/10.1016/j.canlet.2017.08.010DOI Listing
November 2017

Metatropic dysplasia in third trimester of pregnancy and a novel causative variant in the TRPV4 gene.

Eur J Med Genet 2017 Jul 13;60(7):365-368. Epub 2017 Apr 13.

Medical Genetics Unit, Meyer Children's University Hospital, viale Gaetano Pieraccini, 24, 50139 Florence, Italy; Medical Genetics Unit, Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, viale Gaetano Pieraccini, 6, 50139 Florence, Italy. Electronic address:

Prenatal diagnosis of skeletal dysplasias is particularly difficult for many reasons and differentiating these disorders in the prenatal period can be challenging because they are rare and many of the ultrasound findings are not necessarily pathognomonic for a specific disorder. The diagnosis is often made just after birth or exitus. The prenatal diagnosis of osteochondrodysplasias is based predominantly upon fetal ultrasound findings and it focuses substantially on the possible lethality of the disorder, without always being able to find a specific name for the disorder. Metatropic dysplasia is a rare osteochondrodysplasia due to mutations in the TRPV4 gene: TRPV4 is a cation channel, non-selectively permeable to calcium, encoded by a gene on chromosome 12q24.11; it is widely expressed and involved in many different physiological processes through responses to several different stimuli (physical, chemical, and hormonal) in ciliated epithelial cells. The exact incidence of this disorder is not known, however less than a hundred cases have been reported at present, with only two prenatal reports but without any reference to the molecular test. We describe the first report of molecular diagnosis of metatropic dysplasia carried out in prenatal diagnosis: the molecular testing of the TRPV4 (transient receptor potential cation channel, subfamily V, member 4, MIM *605427) gene in our case, in fact, detected a causative variant, confirming the diagnostic suspicion, which was made possible thanks also to the utilization of MRI and CT scan. In our case different imaging methods together with the close cooperation of a multidisciplinary team and test availability, allowed an accurate diagnosis.
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http://dx.doi.org/10.1016/j.ejmg.2017.04.007DOI Listing
July 2017

The acidic microenvironment as a possible niche of dormant tumor cells.

Cell Mol Life Sci 2017 08 22;74(15):2761-2771. Epub 2017 Mar 22.

Dipartimento di Scienze Biomediche Sperimentali e Cliniche "Mario Serio", Università di Firenze, Viale G.B. Morgagni, 50, 50134, Firenze, Italy.

Although surgical excision, chemo-, and radio-therapy are clearly advanced, tumors may relapse due to cells of the so-called "minimal residual disease". Indeed, small clusters of tumor cells persist in host tissues after treatment of the primary tumor elaborating strategies to survive and escape from immunological attacks before their relapse: this variable period of remission is known as "cancer dormancy". Therefore, it is crucial to understand and consider the major concepts addressing dormancy, to identify new targets and disclose potential clinical strategies. Here, we have particularly focused the relationships between tumor microenvironment and cancer dormancy, looking at a re-appreciated aspect of this compartment that is the low extracellular pH. Accumulating evidences indicate that acidity of tumor microenvironment is associated with a poor prognosis of tumor-bearing patients, stimulates a chemo- and radio-therapy resistant phenotype, and suppresses the tumoricidal activity of cytotoxic lymphocytes and natural killer cells, and all these aspects are useful for dormancy. Therefore, this review discusses the possibility that acidity of tumor microenvironment may provide a new, not previously suggested, adequate milieu for "dormancy" of tumor cells.
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http://dx.doi.org/10.1007/s00018-017-2496-yDOI Listing
August 2017

The genetic and clinical spectrum of a large cohort of patients with distal renal tubular acidosis.

Kidney Int 2017 05 21;91(5):1243-1255. Epub 2017 Feb 21.

Medical Genetics, Department of Clinical and Experimental Medicine, University Hospital of Parma, Italy.

Primary distal renal tubular acidosis is a rare genetic disease. Mutations in SLC4A1, ATP6V0A4, and ATP6V1B1 genes have been described as the cause of the disease, transmitted as either an autosomal dominant or recessive trait. Particular clinical features, such as sensorineural hearing loss, have been mainly described in association with mutations in one gene instead of the others. Nevertheless, the diagnosis of distal renal tubular acidosis is essentially based on clinical and laboratory findings, and the series of patients described so far are usually represented by small cohorts. Therefore, a strict genotype-phenotype correlation is still lacking, and questions about whether clinical and laboratory data should direct the genetic analysis remain open. Here, we applied next-generation sequencing in 89 patients with a clinical diagnosis of distal renal tubular acidosis, analyzing the prevalence of genetic defects in SLC4A1, ATP6V0A4, and ATP6V1B1 genes and the clinical phenotype. A genetic cause was determined in 71.9% of cases. In our group of sporadic cases, clinical features, including sensorineural hearing loss, are not specific indicators of the causal underlying gene. Mutations in the ATP6V0A4 gene are quite as frequent as mutations in ATP6V1B1 in patients with recessive disease. Chronic kidney disease was frequent in patients with a long history of the disease. Thus, our results suggest that when distal renal tubular acidosis is suspected, complete genetic testing could be considered, irrespective of the clinical phenotype of the patient.
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http://dx.doi.org/10.1016/j.kint.2016.12.017DOI Listing
May 2017

Targeting the receptor tyrosine kinase RET in combination with aromatase inhibitors in ER positive breast cancer xenografts.

Oncotarget 2016 Dec;7(49):80543-80553

Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy.

The majority of breast cancers are estrogen receptor positive (ER+). Blockade of estrogen biosynthesis by aromatase inhibitors (AIs) is the first-line endocrine therapy for post-menopausal women with ER+ breast cancers. However, AI resistance remains a major challenge. We have demonstrated previously that increased GDNF/RET signaling in ER+ breast cancers promotes AI resistance. Here we investigated the efficacy of different small molecule RET kinase inhibitors, sunitinib, cabozantinib, NVP-BBT594 and NVP-AST487, and the potential of combining a RET inhibitor with the AI letrozole in ER+ breast cancers. The most effective inhibitor identified, NVP-AST487, suppressed GDNF-stimulated RET downstream signaling and 3D tumor spheroid growth. Ovariectomized mice were inoculated with ER+ aromatase-overexpressing MCF7-AROM1 cells and treated with letrozole, NVP-AST487 or the two drugs in combination. Surprisingly, the three treatment regimens showed similar efficacy in impairing MCF7-AROM1 tumor growth in vivo. However in vitro, NVP-AST487 was superior to letrozole in inhibiting the GDNF-induced motility and tumor spheroid growth of MCF7-AROM1 cells and required in combination with letrozole to inhibit GDNF-induced motility in BT474-AROM3 aromatase expressing cells. These data indicate that inhibiting RET is as effective as the current therapeutic regimen of AI therapy but that a combination treatment may delay cancer cell dissemination and metastasis.
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http://dx.doi.org/10.18632/oncotarget.11826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5348339PMC
December 2016

Roles of different IRES-dependent FGF2 isoforms in the acquisition of the major aggressive features of human metastatic melanoma.

J Mol Med (Berl) 2017 01 24;95(1):97-108. Epub 2016 Aug 24.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy.

Fibroblast growth factor 2 (FGF2) is involved in many physiological and pathological processes. Fgf2 deregulation contributes to the acquisition of malignant features of melanoma and other cancers. FGF2 is an alternative translation product expressed as five isoforms, a low-molecular-weight (18 KDa) and four high-molecular-weight (22, 22.5, 24, 34 KDa) isoforms, with different subcellular distributions. An internal ribosomal entry site (IRES) in its mRNA controls the translation of all the isoforms with the exception for the cap-dependent 34 KDa. The 18-KDa isoform has been extensively studied, while very few is known about the roles of high molecular weight isoforms. FGF2 is known to promote melanoma development and progression. To disclose the differential contribution of FGF2 isoforms in melanoma, we forced the expression of IRES-dependent low-molecular-weight (LMW, 18 KDa) and high-molecular-weight (HMW, 22, 22.5, 24 KDa) isoforms in a human metastatic melanoma cell line. This comparative study highlights that, while LMW isoform confers stem-like features to melanoma cells and promotes angiogenesis, HMW isoforms induce higher migratory ability and contribute to tumor perfusion by promoting vasculogenic mimicry (VM) when endothelial cell-driven angiogenesis is lacking. To conclude, FGF2 isoforms mainly behave in specific, antithetical manners, but can cooperate in different steps of tumor progression, providing melanoma cells with major malignant features.

Key Message: FGF2 is an alternative translation product expressed as different isoforms termed LMW and HMW. FGF2 is involved in melanoma development and progression. HMW FGF2 isoforms enhance in vitro motility of melanoma cells. LMW FGF2 confers stem-like features and increases in vivo metastasization. LMW FGF2 promotes angiogenesis while HMW FGF2 induces vasculogenic mimicry.
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http://dx.doi.org/10.1007/s00109-016-1463-7DOI Listing
January 2017

A novel OTX2 gene frameshift mutation in a child with microphthalmia, ectopic pituitary and growth hormone deficiency.

J Pediatr Endocrinol Metab 2016 May;29(5):603-5

OTX2 mutations are reported in patients with eye maldevelopment and in some cases with brain or pituitary abnormalities. We describe a child carrying a novel OTX2 heterozygous mutation. She presented microphthalmia, absence of retinal vascularization, vitreal spots and optic nerve hypoplasia in the right eye and mild macular dystrophy in the left eye. Midline brain structures and cerebral parenchyma were normal, except for the ectopic posterior pituitary gland. OTX2 sequencing showed a heterozygous c.402del mutation. Most of OTX2 mutations are nonsense or frameshift introducing a premature termination codon and resulting in a truncated protein. More rarely missense mutations occur. Our novel OTX2 mutation (c.402del) is a frameshift mutation (p.S135Lfs*43), never reported before, causing a premature codon stop 43 amino-acids downstream, which is predicted to generate a premature truncation. The mutation was associated with microphthalmia and ectopic posterior pituitary.
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http://dx.doi.org/10.1515/jpem-2015-0425DOI Listing
May 2016
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