Tiziana Squillaro

Biological Scientist, PhD

Name Tiziana
Surname Squillaro
Institution Università degli Studi della Campania Luigi Vanvitelli
E-Mail tiziana.squillaro@unicampania.it
Address Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy
Tiziana Squillaro

Member PUBLICATIONS

  • In vitro senescence of rat mesenchymal stem cells is accompanied by downregulation of stemness-related and DNA damage repair genes.

    Publication Date: 01/09/2009 on Stem cells and development
    by Galderisi U, Helmbold H, Squillaro T, Alessio N, Komm N, Khadang B, Cipollaro M, Bohn W, Giordano A
    DOI: 10.1089/scd.2008.0324

    Mesenchymal stem cells (MSCs) are of particular interest because they are being tested using cell and gene therapies for a number of human diseases. MSCs represent a rare population in tissues. Therefore, it is essential to grow MSCs in vitro before putting them into therapeutic use. This is compromised by senescence, limiting the proliferative capacity of MSCs. We analyzed the in vitro senescence of rat MSCs, because this animal is a widespread model for preclinical cell therapy studies. After initial expansion, MSCs showed an increased growth doubling time, lost telomerase activity, and expressed senescence-associated beta-galactosidase. Senescence was accompanied by downregulation of several genes involved in stem cell self-renewal. Of interest, several genes involved in DNA repair also showed a significant downregulation. Entry into senescence occurred with characteristic changes in Retinoblastoma (RB) expression patterns. Rb1 and p107 genes expression decreased during in vitro cultivation. In contrast, pRb2/p130 became the prominent RB protein. This suggests that RB2/P130 could be a marker of senescence or that it even plays a role in triggering the process in MSCs.

  • Genes involved in regulation of stem cell properties: studies on their expression in a small cohort of neuroblastoma patients.

    Publication Date: 01/07/2009 on Cancer biology & therapy
    by Melone MA, Giuliano M, Squillaro T, Alessio N, Casale F, Mattioli E, Cipollaro M, Giordano A, Galderisi U

    Cancer stem cells have been isolated from many tumors. Several evidences prove that neuroblastoma contains its own stem cell-like cancer cells. We chose to analyze 20 neuroblastoma tumor samples in the expression of 13 genes involved in the regulation of stem cell properties to evaluate if their misregulation could have a clinical relevance. In several specimens we detected the expression of genes belonging to the OCT3/SOX2/NANOG/KLF4 core circuitry that acts at the highest level in regulating stem cell biology. This result is in agreement with studies showing the existence of malignant stem cells in neuroblastoma. We also observed differences in the expression of some stemness-related genes that may be useful for developing new prognostic analyses. In fact, preliminary data suggests that the presence/absence of UTF1 along with differences in BMI1 mRNA levels could distinguish low grade neuroblastomas from IV stage tumors.

  • Histone deacetylase inhibitors promote apoptosis and senescence in human mesenchymal stem cells.

    Publication Date: 01/05/2009 on Stem cells and development
    by Di Bernardo G, Squillaro T, Dell'Aversana C, Miceli M, Cipollaro M, Cascino A, Altucci L, Galderisi U
    DOI: 10.1089/scd.2008.0172

    Histone deacetylase inhibitors (HDACi) have received a great amount of attention for their antitumoral properties. Suberoyl anilide hydroxamic acid (SAHA) and MS-275 are among the more promising HDACi for cancer treatments. Although these HDACi compounds exert low toxicity on normal cells, the therapies based on these molecules can cause side effects that can greatly impair the functions of the bone marrow microenvironment. This is a complex system that contains several types of stem cells, such as mesenchymal stem cells (MSCs). We conducted comparative studies on the effects of SAHA and MS-275 on human MSCs in order to ascertain if these compounds can impair the physiology of MSCs. Both SAHA and MS-275 induced an arrest in the cell cycle along with the induction of apoptotic pathways as evidenced by flow cytometry, annexin assay, detection of activated caspase 9, and molecular analysis of Bax/Bcl-2 expression. The MS-275 treatment induced an increase of senescent cells, whereas in cells treated with SAHA, we detected a reduction of senescent cells compared to the control. We hypothesize that SAHA preferentially transactivates apoptotic genes, thereby inducing a great majority of the damaged cells to die by programmed cell death rather than senescence. Following the HDACi treatment, we observed a decrease in the expression of some genes that are involved in the regulation of stem cell properties. This suggests that SAHA and MS-275 could also be involved in the impairment of the stemness characteristics of MSCs. The phenomena that were induced by HDACi treatment were associated with an upregulation of several cyclin kinase inhibitors. By contrast, the p53-p21 pathway is apparently not involved in these processes.

  • A case report: bone marrow mesenchymal stem cells from a Rett syndrome patient are prone to senescence and show a lower degree of apoptosis.

    Publication Date: 15/04/2008 on Journal of cellular biochemistry
    by Squillaro T, Hayek G, Farina E, Cipollaro M, Renieri A, Galderisi U
    DOI: 10.1002/jcb.21582

    Rett syndrome (RTT) is one of the most common genetic diseases responsible for a progressive disabling neurodevelopmental disorder. Mutations in the MeCP2 gene were identified in the great majority of RTT patients. MeCP2 protein binds to methylated DNA and produces changes in chromatin structure. This is a key event in regulation of gene expression. It has been suggested that MeCP2 might be important for neuronal development. Moreover, the frequent occurrence of osteoporosis and scoliosis in RTT patients suggests impaired bone formation and/or remodeling. Mesenchymal stem cells (MSCs) can differentiate as mesodermal cells such as bone, cartilage cells, and adipocytes. MSCs have been shown to possess great somatic plasticity; in fact, they can differentiate as neurons and astrocytes. We studied RTT patients' MSCs because they are progenitors of osteocytes, and it has been suggested that RTT patients' osteogenesis could be impaired. Moreover, MSCs might represent a useful model for the study of neurogenesis. MSCs from RTT patient showed precocious signs of senescence in a comparison with the MSCs of healthy-patient control groups. This was in agreement with the reduced gene-expression in the control of stem cell self-renewal and upregulation of lineage specific genes, such as those involved in osteogenesis and neural development. Control groups enabled us to observe a lower degree of apoptosis in RTT patient cells. This means that aberrant stem/progenitor cells, instead of being eliminated, can survive and become senescent. Our research provides a new insight into RTT syndrome. Senescence phenomena could be involved in triggering RTT syndrome-associated diseases.

  • Frequency of the LRRK2 G2019S mutation in Italian patients affected by Parkinson's disease.

    Publication Date: 01/01/2007 on Journal of human genetics
    by Squillaro T, Cambi F, Ciacci G, Rossi S, Ulivelli M, Malandrini A, Mencarelli MA, Mari F, Renieri A, Ariani F
    DOI: 10.1007/s10038-006-0105-2

    Mutations in the gene Leucine-Rich Repeat Kinase 2 (LRRK2) have been identified in both dominant and sporadic cases affected by Parkinson's disease (PD). The LRRK2 G2019S mutation (c.6055G>A) is the most frequent substitution in Caucasians, accounting for approximately 5-6% of familial and 0.5-2.0% of apparently sporadic PD cases. We investigated the frequency of the LRRK2 G2019S mutation in 98 unrelated Italian PD patients, including 12 probands belonging to families compatible with autosomal dominant inheritance (12%) and 86 sporadic cases (88%). We detected the G2019S mutation in one sporadic female patient (1.2%). These results confirm that the G2019S mutation is a relevant cause of sporadic PD cases in the Italian population and stress the importance of performing this genetic test, which has important implications for genetic counselling.