Maria Gkotzamanidou

Peripheral T-cell lymphoma: the role of hematopoietic stem cell transplantation.

Peripheral T-cell lymphoma (PTCL) is a rare and heterogeneous group of non-Hodgkin lymphomas (NHLs). Whereas the incidence of the disease appears to increase during last decades and the prognosis remains dramatically poor, so far no standard treatment has been established. High-dose chemotherapy and autologous stem cell transplantation (HDT-ASCT) has been proven effective in relapsed PTCL, while retrospective studies have shown a survival benefit as first-line treatment in some subsets of PTCL patients. However, given disease rarity, there is a paucity of randomized trials in both upfront and relapse setting. Here, we critically evaluated eligible prospective and retrospective studies that address the role of ASCT in treatment of PTCL, with respect to quality of design and performance. Additionally, the role of allogeneic transplantation has been reviewed. The comparison of ASCT with novel agents that emerge or the combination of both, are to be ascertained via prospective randomized trials in this field.

Transcription factor-pathway co-expression analysis reveals cooperation between SP1 and ESR1 on dysregulating cell cycle arrest in non-hyperdiploid multiple myeloma

Multiple myeloma is a hematological cancer of plasma B cells and remains incurable. Two major subtypes of myeloma, hyperdiploid MM (HMM) and non-hyperdiploid MM (NHMM), have distinct chromosomal alterations and different survival outcomes. Transcription factors (TrFs) have been implicated in myeloma oncogenesis, but their dysregulation in myeloma subtypes are less studied. Here, we developed a TrF-pathway coexpression analysis to identify altered coexpression between two sample types. We apply the method to the two myeloma subtypes and the cell cycle arrest pathway, which is significantly differentially expressed between the two subtypes. We find that TrFs MYC, nuclear factor-κB and HOXA9 have significantly lower coexpression with cell cycle arrest in HMM, co-occurring with their overactivation in HMM. In contrast, TrFs ESR1 (estrogen receptor 1), SP1 and E2F1 have significantly lower coexpression with cell cycle arrest in NHMM. SP1 chromatin immunoprecipitation targets are enriched by cell cycle arrest genes. These results motivate a cooperation model of ESR1 and SP1 in regulating cell cycle arrest, and a hypothesis that their overactivation in NHMM disrupts proper regulation of cell cycle arrest. Cotargeting ESR1 and SP1 shows a synergistic effect on inhibiting myeloma proliferation in NHMM cell lines. Therefore, studying TrF-pathway coexpression dysregulation in human cancers facilitates forming novel hypotheses toward clinical utility.

Progressive changes in chromatin structure and DNA damage response signals in bone marrow and peripheral blood during myelomagenesis

The molecular pathways implicated in multiple myeloma (MM) development are rather unknown. We studied epigenetic and DNA damage response (DDR) signals at selected model loci (N-ras, p53, d-globin) in bone marrow plasma cells and peripheral blood mononuclear cells (PBMCs) from patients with monoclonal gammopathy of undetermined significance (MGUS; n=20), smoldering/asymptomatic MM (SMM; n=29) and MM (n=18), as well as in healthy control-derived PBMCs (n=20). In both tissues analyzed, a progressive, significant increase in the looseness of local chromatin structure, gene expression levels and DNA repair efficiency from MGUS to SMM and finally to MM was observed (all P<0.002). Following ex vivo treatment with melphalan, a gradual suppression of the apoptotic pathway occurred in samples collected at different stages of myelomagenesis, with the severity and duration of the inhibition of RNA synthesis, p53 phosphorylation at serine15 and induction of apoptosis being higher in MGUS than SMM and lowest in MM patients (all P<0.0103). Interestingly, for all endpoints analyzed, a strong correlation between plasma cells and corresponding PBMCs was observed (all P<0.0003). We conclude that progressive changes in chromatin structure, transcriptional activity and DDR pathways during myelomagenesis occur in malignant plasma cells and that these changes are also reflected in PBMCs.

Immunopathology and Immunotherapy of Hodgkin Lymphoma

Immunotherapy has led to promising results in the treatment of malignancies in recent decades. In view of the suboptimal results obtained by applying other treatment modalities in the treatment of Hodgkin lymphoma (HL), attention has been drawn to immunotherapy as an efficient alternative or complement therapy. This chapter seeks to discuss a wide spectrum of immunotherapeutic approaches, from initial monoclonal antibodies to novel techniques developed in recent years, which are still at their infancy. Since correct understanding of the underlying immunopathology seems inevitable in efficient immunotherapy and the development of future techniques, a brief description with the emphasis on suitable targets for immunotherapy is given before discussing various immunotherapies.

Deficient double strand breaks repair of bone marrow plasma cells correlates with better clinical outcome of multiple myeloma patients

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA DNA interstrand crosslinks (ICLs) are complex DNA lesions generated by bi-functional alkylating agents, a class of compounds extensively used in cancer chemotherapy. During ICL repair, replication forks stall at the ICL, inducing the formation of a lethal form of DNA damage termed DNA double-strand breaks (DSBs), which are repaired mainly by homologous recombination (HR) and non-homologous end joining (NHEJ). In this study we applied the properties of the ICL-inducing agent melphalan as a model, to elucidate the underlying mechanisms in processing and repair of ICLs. We studied two human multiple myeloma (HMCLs) cell lines (melphalan-sensitive RPMI-8226 and -resistant LR5) and CD138+ bone marrow plasma cells (BMPCs) from 15 newly diagnosed MM patients (8M/7F; median age 61 years) before they receive high-dose melphalan therapy supported by ASCT. HMCLs and BMPCs were treated with melphalan alone or in combination with RI-1 (selective inhibitor of HR) or SCR7 (selective inhibitor of NHEJ) and the extent of the N-ras-specific ICLs using a quantitative PCR assay and DSBs (intermediates of ICL repair) using γH2Ax foci measurements by confocal microscopy were evaluated. The induction of the melphalan-induced apoptosis using a photometric enzyme-assay was also evaluated. The ICLs repair efficiency correlated with response to treatment and could identify 2 groups of patients: non-responders (<PR, n=6), with higher ICLs repair efficiency (t1/2 23h) and responders (≥PR, n=9) with lower efficiency (t1/2 48h). Moreover, using γ-H2AX foci formation/removal measurement, we found that the repair efficiency of DSBs in BMPCs was significantly higher in non-responders (t1/2 9h) than in responders (t1/2 12h) (all p<0.001). Also, the melphalan-induced apoptosis in BMPCs inversely correlated with the repair efficiencies of ICLs and DSBs, with the toxicity being higher in responders than in non-responders. Furthermore, LR5 cells showed higher repair efficiency of both ICLs and DSBs and lower toxicity than RPMI-8226 cells. Interestingly, in all cellular populations analysed, significant correlation between ICL and DSBs levels was observed. To further elucidate the mechanism of drug-induced DSBs repair, HMCLs and BMPCs were treated with melphalan in combination with nontoxic doses of RI-1 or SCR7. We found that the combined treatment of melphalan with RI-1 or SCR7 significantly increased the induction of the melphalan-only phosphorylation of H2AX, delayed the repair of ICLs and strongly enhanced the cytotoxic activity of melphalan (all p<0.01). Collectively, our study demonstrates that significant changes in the repair efficiency of DSBs occur in MM. These changes affect the repair of ICLs, modify drug sensitivity of malignant BMPCs, and correlate with clinical outcome. Specific inhibition of HR and/or NHEJ might be an effective strategy to enhance sensitivity of cancer cells in MM. Citation Format: Maria Gkotzamanidou, Masood Shammas, Evangelos Terpos, Sathees C. Raghavan, Kenneth C. Anderson, Nikhil C. Munshi, Meletios - Athanasios Dimopoulos, Vassilis L. Souliotis. Deficient double strand breaks repair of bone marrow plasma cells correlates with better clinical outcome of multiple myeloma patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4762. doi:10.1158/1538-7445.AM2014-4762