Prof. Anita De Rossi, PhD
Position: Full Professor of Pathology, Medical School, University of Padova
Head of Viral Oncology Unit, IOV-IRCCS, Padova
Foreign working experiences: National Cancer Institute, Bethesda, USA, Laboratory of Viral Carcinogenesis (Prof. P Fischinger, Head) in 1980, and Laboratory of Tumor Cell Biology ( Prof. R. Gallo, Head) in 1984, 1985, 1988.
Major research interests: Anita De Rossi has long been involved in studying oncogenic retroviruses. Since 1983, her research has shifted from murine to human retroviruses in both experimental models and clinical settings. Significant progress has been made in understanding the vertical transmission and disease progression of pediatric HIV infection. Her studies in this field address the virological and immunological correlates of pediatric disease outcomes and are some of the first to indicate that HIV infection from mother-to-child mainly occurs during the intrapartum period and that host factors may restrict HIV infection (Aids 1994; Aids 1995; J Clin Invest 1996). Her interest has expanded to studying tumors in immunocompromised patients, with particular regard to EBV-related lymphomagenesis in HIV-infected or transplant patients (Blood 1996; Cancer Letter 2015), and more recently to telomere/telomerase interplay in virus-driven and virus-independent malignancies. Her studies in this field are some of the first to indicate that LMP1, the viral protein of EBV, activates at transcriptional level TERT, the catalytic component of telomerase (J Virol 2008) Clin Cancer Res 2013), and that quantification of TERT in plasma may represent a minimally invasive tool for monitoring malignancies (Clin Cancer Res 2008) and response to therapy (Ann Surg Oncol 2012). In addition, her studies provide the rationale for considering inhibition of TERT a useful approach for setting up new therapeutic strategies (Clin Cancer Res ,2013; Cell Death Dis, 2015).
Unit of Viral Oncology
Immunology and Molecular Oncology Unit
– Department of Translational Oncology and Health Services, IOV-IRCCS
– Section of Oncology and Immunology-DiSCOG, University of Padova
Mechanisms promoting Epstein Barr Virus (EBV)-driven malignancies
Better understanding of the mechanisms promoting malignancies associated with EBV will allow us to personalize monitoring of at-risk subjects (e.g., transplant patients) and to design new strategies to prevent/cure EBV-driven malignancies.
Studies to assess the host characteristcics which allow EBV expansion and the mechanisms by which EBV promotes viral latent cycle and immortalization of infected cells, two key motifs for EBV-driven malignancies.
Infection of B cells with EBV in vitro causes sustained cell proliferation which may generate immortalized lymphoblastoid cell lines (LCL). This growth-transforming activity is central to the etiology of B-cell malignancies arising in a context of immunodepression, such as post-transplant lymphoproliferative disorders (PTLD) and Non Hodgkin’s Lymphoma. Organ transplantation is often the only treatment for end state organ failure, such as heart, liver and kidney failure, with more than 117,000 transplants performed worldwide in 2013 (31,000 in Europe). EBV is found in more than 90% of PTLD occurring during the first year after transplantation, with a significant increase in EBV-DNA levels in peripheral blood. Besides immunodepression, immune activation by microbial pathogen-associated molecular patterns (PAMPs) and endogenous damage-associated molecular patterns (DAMPs) may play an important role in the expansion of B cells and increase in EBV level. In addition, persistent immune activation/inflammation may promote accelerated immunesenescence, favoring the onset of solid tumors in which the virus may play an indirect role. Notably, EBV-driven malignancies are associated with the selective expression of latent oncogenic viral proteins, including LMP1, and cell telomerase, which is essential for tumor formation/progression.
- Relationship between immune activation and EBV load. Studies have demonstrated a strong relationship between proinflammatory cytokines ( IL-6, IL-10, TNF-α) and level of EBV load in cells and plasma (Petrara et al, J Clin Virol , 2012; Petrara et al, Front Microbiol, 2013; Petrara et al, J Infect Dis 2014; Petrara et al, Cancer Lett, 2015).
- Cross-talk talk between EBV and telomerase. Our studies demonstrate that EBV oncoprotein LMP1 activates at transcriptional levels TERT, the catalytic component of telomerase (Terrin et al, Int J Cancer 2007; J Virol, 2008). In turn, TERT plays an important role in inhibiting the virus lytic cycle, thereby favouring the induction and maintenance of EBV latency in primary B lymphocytes, a prerequisite for EBV-transformation. (Giunco et al, Clin Cancer Res 2013). The mechanism by which TERT inhibits viral lytic cycle occurs through the NOTCH2 pathway: TERT activates NOTCH2, the major NOTCH family member in B cells, which in turn activates BATF, a trancriptional factor which negatively affects the expression of BZLF1, the master regulator of viral lytic cycle. Inhibition of TERT induces the expression of viral lytic cycle (Giunco et al, Cell Death Dis, 2015). As the viral lytic cycle is accompanied by the death of infected cells, inhibition of TERT may be a useful approach for setting up new therapeutic strategies.
- To study the relationship between PAMPs, DAMPs, immune stimulation, EBV reactivation and expansion of EBV infected cells.
- To study the role of circulating TERT mRNA as a diagnostic/prognostic marker of EBV-related malignancies.
- To study the inhibition of TERT as a therapeutic strategy against EBV-driven malignancies.
New approaches for the diagnosis and monitoring of tumors: telomere/telomerase complex
The definition of the prognostic/predictive value of telomere and telomerase, main drivers of the unlimited replicative capacity of tumor cells, will allow us to design new approaches for minimally invasive monitoring of tumor onset/progression and response to therapy.
Unlimited replicative potential is the hallmark of cancer cells. Telomere/telomerase interplay is the major driver of replicative potential. Understanding the value of costitutive telomere length and circulating levels of TERT, the catalytic component of telomerase, as prognostic/predictive factors may allow us to design new approaches for minimally invasive monitoring of tumor onset/progression and response to therapy.
Telomere shortening, which occurs at each cell division, restricts cell proliferation in normal somatic cells. Maintenance of telomere length, required for the unlimited cell proliferation displayed by cancer cells, is provided by telomerase activity, expressed in the vast majority of tumors. Many tumor-based studies have demonstrated that neoplastic cells generally have shorter telomeres than their adjacent non-cancerous mucosa, strongly supporting the concept that telomere erosion is a critical event in carcinogenesis, by promoting genetic instability. Telomerase reverse transcriptase (TERT), the catalytic component of the telomerase complex, is usually absent in normal somatic cells, but is expressed at variable levels in tumors, and specific mutations in its promoter may influence TERT levels. A body of data indicates that telomere length and levels of TERT/telomerase activity may be prognostic markers in cancers. Circulating cell-free TERT RNA may also be a promising marker for minimally invasive monitoring of disease progression and response to therapy.
The team has set up molecular methods based on multiplex PCR and Digital PCR to estimate telomere length, levels of TERT mRNA and telomerase activity. The main results of studies performed in collaboration with clinical centers have demonstrated that:
- telomere length and/or TERT levels are independent prognostic factors in chronic lymphocytic leukemia (Terrin et al, Leukemia 2007; Rampazzo et al, Heamatologica, 2012;) and in colon cancer ( Terrin et al, Clin cancer Res 2008; Bertorelle et al, Brit J Cancer, 2013);
- in head and neck tumors, TERT levels are prognostic of disease progression, and telonmere length in mucosa adjacent to tumors is a marker of field cancerization and prognostic of local relapse (Boscolo-Rizzo et al, Oral Oncol 2015);
- constitutive short telomere, while reducing the risk of familial melanoma, is a risk factor for the onset of sporadic melanoma (Menin et al, Br J Dermatol, 2015);
- constitutive short telomere and low thymic output are independent risk factors for tumor onset in elderly patients (Falci et al, Exp Gerontol,2013);
- circulating TERT mRNA may be a marker of therapy response in patients with rectal cancer (Pucciarelli et al, Ann Surg Oncol, 2012);
- high levels of endogenous or ectopic expression of TERT improve resistance to apoptosis in in vitro cultured tumor cells exposed to antineoplastic agents, thus suggesting that TERT, besides maintaining telomere length, may have additional functions in tumor cells (ongoing research).
- evaluation of predictive/prognostic role of constitutive telomere length in response to therapy/disease progression in elderly patients with colorectal cancer;
- evaluation of predictive role of circulating TERT in response to neoadjuvant therapy in patients with rectal cancer;
- evaluation of prognostic role of circulating TERT in patients with solid tumors (colorectal cancer, head and neck cancers);
- studies of extra-telomeric functions of TERT in in vitro models of viral-driven and viral-independent B-cell malignancies.
- Maria Raffaella Petrara
- Marisa Zanchetta
- Francesco Carmona
- Francesca Pozzolo
- Enrica Rampazzo
- Silvia Giunco
- Giunco S, Dolcetti R, Keppel S, Celeghin A, Indraccolo S, Dal Col J, Mastorci K, De Rossi A. hTERT inhibition triggers Epstein-Barr virus lytic cycle and apoptosis in immortalized and transformed B cells: a basis for new therapies. Clin Cancer Res 2013; 19: 2036-2047.
- Petrara MR, Giunco S, Serraino D, Dolcetti R, De Rossi A. Post-transplant lymphoproliferative disorders: from epidemiology to pathogenesis-driven treatment. Cancer Lett. 2015; 369: 37-44.
- Boscolo-Rizzo P, Rampazzo E, Perissinotto E, Piano MA, Giunco S, Baboci L, Spinato G, Spinato R,Tirelli G, Da Mosto MC, Del Mistro A, De Rossi A. Telomere shortening in mucosa surrounding the tumor: Biosensor of field cancerization and prognostic marker of mucosal failure in head and neck squamous cell carcinoma. Oral Oncol. 2015; 51: 500-507.