Publications by authors named "Andrea Speciale"

11 Publications

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Evaluating the Influence of a G-Quadruplex Prone Sequence on the Transactivation Potential by Wild-Type and/or Mutant P53 Family Proteins through a Yeast-Based Functional Assay.

Genes (Basel) 2021 Feb 15;12(2). Epub 2021 Feb 15.

Mutagenesis and Cancer Prevention Unit, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy.

P53, P63, and P73 proteins belong to the P53 family of transcription factors, sharing a common gene organization that, from the P1 and P2 promoters, produces two groups of mRNAs encoding proteins with different N-terminal regions; moreover, alternative splicing events at C-terminus further contribute to the generation of multiple isoforms. P53 family proteins can influence a plethora of cellular pathways mainly through the direct binding to specific DNA sequences known as response elements (REs), and the transactivation of the corresponding target genes. However, the transcriptional activation by P53 family members can be regulated at multiple levels, including the DNA topology at responsive promoters. Here, by using a yeast-based functional assay, we evaluated the influence that a G-quadruplex (G4) prone sequence adjacent to the p53 RE derived from the apoptotic target gene can exert on the transactivation potential of full-length and N-terminal truncated P53 family α isoforms (wild-type and mutant). Our results show that the presence of a G4 prone sequence upstream or downstream of the P53 RE leads to significant changes in the relative activity of P53 family proteins, emphasizing the potential role of structural DNA features as modifiers of P53 family functions at target promoter sites.
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http://dx.doi.org/10.3390/genes12020277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7919268PMC
February 2021

Potential Role of miRNAs in the Acquisition of Chemoresistance in Neuroblastoma.

J Pers Med 2021 Feb 7;11(2). Epub 2021 Feb 7.

Department of Experimental Medicine, University of Genova, 16100 Genova, Italy.

Neuroblastoma (NB) accounts for about 8-10% of pediatric cancers, and the main causes of death are the presence of metastases and the acquisition of chemoresistance. Metastatic NB is characterized by amplification that correlates with changes in the expression of miRNAs, which are small non-coding RNA sequences, playing a crucial role in NB development and chemoresistance. In the present study, miRNA expression was analyzed in two human -amplified NB cell lines, one sensitive (HTLA-230) and one resistant to Etoposide (ER-HTLA), by microarray and RT-qPCR techniques. These analyses showed that miRNA-15a, -16-1, -19b, -218, and -338 were down-regulated in ER-HTLA cells. In order to validate the presence of this down-regulation in vivo, the expression of these miRNAs was analyzed in primary tumors, metastases, and bone marrow of therapy responder and non-responder pediatric patients. Principal component analysis data showed that the expression of miRNA-19b, -218, and -338 influenced metastases, and that the expression levels of all miRNAs analyzed were higher in therapy responders in respect to non-responders. Collectively, these findings suggest that these miRNAs might be involved in the regulation of the drug response, and could be employed for therapeutic purposes.
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http://dx.doi.org/10.3390/jpm11020107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7916079PMC
February 2021

Antitumor Effects of PRIMA-1 and PRIMA-1 (APR246) in Hematological Malignancies: Still a Mutant P53-Dependent Affair?

Cells 2021 Jan 7;10(1). Epub 2021 Jan 7.

Mutagenesis and Cancer Prevention Unit, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy.

Because of its role in the regulation of the cell cycle, DNA damage response, apoptosis, DNA repair, cell migration, autophagy, and cell metabolism, the tumor suppressor gene is a key player for cellular homeostasis. gene is mutated in more than 50% of human cancers, although its overall dysfunction may be even more frequent. mutations are detected in a lower percentage of hematological malignancies compared to solid tumors, but their frequency generally increases with disease progression, generating adverse effects such as resistance to chemotherapy. Due to the crucial role of P53 in therapy response, several molecules have been developed to re-establish the wild-type P53 function to mutant P53. PRIMA-1 and its methylated form PRIMA-1 (also named APR246) are capable of restoring the wild-type conformation to mutant P53 and inducing apoptosis in cancer cells; however, they also possess mutant P53-independent properties. This review presents the activities of PRIMA-1 and PRIMA-1/APR246 and describes their potential use in hematological malignancies.
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http://dx.doi.org/10.3390/cells10010098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7827888PMC
January 2021

MicroRNA-Mutant P53 Crosstalk in Chemoresistance: A Hint to Monitor Therapy Outcome.

Microrna 2020 ;9(5):322-335

Mutagenesis and Cancer Prevention Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, Genoa, Italy.

The chemoresistance of cancer cells is a multifactorial mechanism in which de-regulated apoptotic pathways, the oxidative response and cancer cell migration play a crucial role. A key player in the control of such pathways is the tumor suppressor gene TP53, also defined as the "guardian of the genome", encoding the P53 tetrameric transcription factor. P53, following cell injuries, can activate the transcription of several target genes crucial for the induction of apoptosis, cell cycle arrest, modulation of senescence, DNA repair, autophagy and metabolism. Importantly, TP53 gene is mutated in nearly 50% of human cancers, implying an altered expression of target genes in cancer cells. The presence of TP53 mutations can also affect the expression of several small noncoding RNAs (microRNAs or miRNAs) involved in the same regulation of the apoptotic signaling, cell cycle regulation and cell migration. In mutant P53 expressing tumors, some miRNAs resulted in being down-regulated, while others appeared to be up-regulated as demonstrated by in vitro and in vivo studies. Thus, the expression level of specific P53 responsive miRNAs could be used as a marker of cancer progression and therapy performance. In the present review, we will summarize the role of P53-related miRNAs and their clinical relevance in monitoring therapy outcome and progression of cancers with mutant P53.
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http://dx.doi.org/10.2174/2211536609666201209151659DOI Listing
January 2020

Heterogeneity of Mutations and P53 Protein Residual Function in Cancer: Does It Matter?

Front Oncol 2020 28;10:593383. Epub 2020 Oct 28.

Mutagenesis and Cancer Prevention Unit, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genoa, Italy.

The human locus, located on the short arm of chromosome 17, encodes a tumour suppressor protein which functions as a tetrameric transcription factor capable of regulating the expression of a plethora of target genes involved in cell cycle arrest, apoptosis, DNA repair, autophagy, and metabolism regulation. is the most commonly mutated gene in human cancer cells and germ-line mutations are responsible for the cancer-prone Li-Fraumeni syndrome. When mutated, the gene generally presents missense mutations, which can be distributed throughout the coding sequence, although they are found most frequently in the central DNA binding domain of the protein. mutations represent an important prognostic and predictive marker in cancer. The presence of a mutation does not necessarily imply a complete P53 inactivation; in fact, mutant P53 proteins are classified based on the effects on P53 protein function. Different models have been used to explore these never-ending facets of mutations, generating abundant experimental data on their functional impact. Here, we briefly review the studies analysing the consequences of mutations on P53 protein function and their possible implications for clinical outcome. The focus shall be on Chronic Lymphocytic Leukemia (CLL), which also has generated considerable discussion on the role of mutations for therapy decisions.
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http://dx.doi.org/10.3389/fonc.2020.593383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655923PMC
October 2020

Time to first treatment and P53 dysfunction in chronic lymphocytic leukaemia: results of the O-CLL1 study in early stage patients.

Sci Rep 2020 10 28;10(1):18427. Epub 2020 Oct 28.

Biotechnology Research Unit, Aprigliano, A.O./ASP of Cosenza, 87100, Cosenza, Italy.

Chronic lymphocytic leukaemia (CLL) is characterised by a heterogeneous clinical course. Such heterogeneity is associated with a number of markers, including TP53 gene inactivation. While TP53 gene alterations determine resistance to chemotherapy, it is not clear whether they can influence early disease progression. To clarify this issue, TP53 mutations and deletions of the corresponding locus [del(17p)] were evaluated in 469 cases from the O-CLL1 observational study that recruited a cohort of clinically and molecularly characterised Binet stage A patients. Twenty-four cases harboured somatic TP53 mutations [accompanied by del(17p) in 9 cases], 2 patients had del(17p) only, and 5 patients had TP53 germ-line variants. While del(17p) with or without TP53 mutations was capable of significantly predicting the time to first treatment, a reliable measure of disease progression, TP53 mutations were not. This was true for cases with high or low variant allele frequency. The lack of predictive ability was independent of the functional features of the mutant P53 protein in terms of transactivation and dominant negative potential. TP53 mutations alone were more frequent in patients with mutated IGHV genes, whereas del(17p) was associated with the presence of adverse prognostic factors, including CD38 positivity, unmutated-IGHV gene status, and NOTCH1 mutations.
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http://dx.doi.org/10.1038/s41598-020-75364-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7595214PMC
October 2020

Biological evaluation of pyrazolyl-urea and dihydro-imidazo-pyrazolyl-urea derivatives as potential anti-angiogenetic agents in the treatment of neuroblastoma.

Oncotarget 2020 Sep 15;11(37):3459-3472. Epub 2020 Sep 15.

Department of Experimental Medicine, General Pathology Section, University of Genoa, Genoa, Italy.

Pyrazolyl-urea and dihydro-imidazo-pyrazolyl-urea compounds (STIRUR 13, STIRUR 41 and BUR 12) have been demonstrated to exert a strong inhibitory effect on interleukin 8 or N-formyl-methionyl-leucyl-phenylalanine-induced chemotaxis of human neutrophils. Since the migration of cancer cells is comparable to that of neutrophils, the purpose of this study is to evaluate the biological effect of STIRUR 13, STIRUR 41 and BUR 12 on ACN and HTLA-230, two neuroblastoma (NB) cell lines with different degree of malignancy. HTLA-230 cells, stage-IV NB cells, have high plasticity and can serve as progenitors of endothelial cells. The results herein reported show that the three tested compounds were not cytotoxic for both NB cells and did not alter their clonogenic potential. However, all compounds were able to inhibit the ability of HTLA-230 to form vascular-like structures. On the basis of these findings, pyrazolyl-urea and dihydro-imidazo-pyrazolyl-urea derivatives could be proposed as agents potentially effective in counteracting NB malignancy by inhibiting cell migration and tumor angiogenesis which represent important hallmarks responsible for cancer survival and progression.
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http://dx.doi.org/10.18632/oncotarget.27733DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7500105PMC
September 2020

MYC Expression and Metabolic Redox Changes in Cancer Cells: A Synergy Able to Induce Chemoresistance.

Oxid Med Cell Longev 2019 25;2019:7346492. Epub 2019 Jun 25.

Department of Experimental Medicine, General Pathology Section, University of Genova, Italy.

Chemoresistance is due to multiple factors including the induction of a metabolic adaptation of tumor cells. In fact, in these cells, stress conditions induced by therapies stimulate a metabolic reprogramming which involves the strengthening of various pathways such as glycolysis, glutaminolysis and the pentose phosphate pathway. This metabolic reprogramming is the result of a complex network of mechanisms that, through the activation of oncogenes (i.e., MYC, HIF1, and PI3K) or the downregulation of tumor suppressors (i.e., TP53), induces an increased expression of glucose and/or glutamine transporters and of glycolytic enzymes. Therefore, in order to overcome chemoresistance, it is necessary to develop combined therapies which are able to selectively and simultaneously act on the multiple molecular targets responsible for this adaptation. This review is focused on highlighting the role of MYC in modulating the epigenetic redox changes which are crucial in the acquisition of therapy resistance.
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http://dx.doi.org/10.1155/2019/7346492DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614970PMC
February 2020

Etoposide-resistance in a neuroblastoma model cell line is associated with 13q14.3 mono-allelic deletion and miRNA-15a/16-1 down-regulation.

Sci Rep 2018 09 13;8(1):13762. Epub 2018 Sep 13.

Department of Experimental Medicine, General Pathology Section, University of Genova, Genova, Italy.

Drug resistance is the major obstacle in successfully treating high-risk neuroblastoma. The aim of this study was to investigate the basis of etoposide-resistance in neuroblastoma. To this end, a MYCN-amplified neuroblastoma cell line (HTLA-230) was treated with increasing etoposide concentrations and an etoposide-resistant cell line (HTLA-ER) was obtained. HTLA-ER cells, following etoposide exposure, evaded apoptosis by altering Bax/Bcl2 ratio. While both cell populations shared a homozygous TP53 mutation encoding a partially-functioning protein, a mono-allelic deletion of 13q14.3 locus, where the P53 inducible miRNAs 15a/16-1 are located, and the consequent miRNA down-regulation were detected only in HTLA-ER cells. This event correlated with BMI-1 oncoprotein up-regulation which caused a decrease in p16 tumor suppressor content and a metabolic adaptation of HTLA-ER cells. These results, taken collectively, highlight the role of miRNAs 15a/16-1 as markers of chemoresistance.
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http://dx.doi.org/10.1038/s41598-018-32195-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6137223PMC
September 2018

Matrine in association with FD‑2 stimulates F508del‑cystic fibrosis transmembrane conductance regulator activity in the presence of corrector VX809.

Mol Med Rep 2017 Dec 6;16(6):8849-8853. Epub 2017 Oct 6.

Department of Experimental Medicine, University of Genoa, I‑16132 Genoa, Italy.

Cystic fibrosis is caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and the predominant mutation is termed Phe508del (F508del). Therapy for F508del‑CFTR patients is based on the use of Orkambi®, a combination of VX809 and VX770. However, though Orkambi leads to an improvement in the lung function of patients, a progressive reduction in its efficacy has been observed. In order to overcome this effect, the aim of the present study was to investigate the role of matrine and the in‑house compound FD‑2 in increasing the action of VX809 and VX770. Fischer rat thyroid cells overexpressing F508del‑CFTR were treated with matrine, VX809 (corrector) and/or with a number of potentiators (VX770, FD‑1 and FD‑2). The results demonstrated that matrine was able to stimulate CFTR activity and, in association with FD‑2, increased the functionality of the channel in the presence of VX809. Based on these results, it may be hypothesized that FD‑2 may be a novel and more effective potentiator compared with VX770.
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http://dx.doi.org/10.3892/mmr.2017.7736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5779973PMC
December 2017

Glutathione-mediated antioxidant response and aerobic metabolism: two crucial factors involved in determining the multi-drug resistance of high-risk neuroblastoma.

Oncotarget 2016 Oct;7(43):70715-70737

Department of Experimental Medicine, University of Genova, Genova, Italy.

Neuroblastoma, a paediatric malignant tumor, is initially sensitive to etoposide, a drug to which many patients develop chemoresistance. In order to investigate the molecular mechanisms responsible for etoposide chemoresistance, HTLA-230, a human MYCN-amplified neuroblastoma cell line, was chronically treated with etoposide at a concentration that in vitro mimics the clinically-used dose. The selected cells (HTLA-Chr) acquire multi-drug resistance (MDR), becoming less sensitive than parental cells to high doses of etoposide or doxorubicin. MDR is due to several mechanisms that together contribute to maintaining non-toxic levels of H2O2. In fact, HTLA-Chr cells, while having an efficient aerobic metabolism, are also characterized by an up-regulation of catalase activity and higher levels of reduced glutathione (GSH), a thiol antioxidant compound. The combination of such mechanisms contributes to prevent membrane lipoperoxidation and cell death. Treatment of HTLA-Chr cells with L-Buthionine-sulfoximine, an inhibitor of GSH biosynthesis, markedly reduces their tumorigenic potential that is instead enhanced by the exposure to N-Acetylcysteine, able to promote GSH synthesis.Collectively, these results demonstrate that GSH and GSH-related responses play a crucial role in the acquisition of MDR and suggest that GSH level monitoring is an efficient strategy to early identify the onset of drug resistance and to control the patient's response to therapy.
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http://dx.doi.org/10.18632/oncotarget.12209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5342585PMC
October 2016