Magdalena Witkowska

Inhibition of the PI3K/Akt/mTOR Signaling Pathway in Diffuse Large B-Cell Lymphoma: Current Knowledge and Clinical Significance

Diffuse large B-cell lymphoma (DLBCL) is one of the most common non-Hodgkin lymphomas in adults. The disease is very heterogeneous in its presentation, that is DLBCL patients may differ from each other not only in regard to histology of tissue infiltration, clinical course or response to treatment, but also in respect to diversity in gene expression profiling. A growing body of knowledge on the biology of DLBCL, including abnormalities in intracellular signaling, has allowed the development of new treatment strategies, specifically directed against lymphoma cells. The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway plays an important role in controlling proliferation and survival of tumor cells in various types of malignancies, including DLBCL, and therefore it may be a promising target for therapeutic intervention. Currently, novel anticancer drugs are undergoing assessment in different phases of clinical trials in aggressive lymphomas, with promising outcomes. In this review we present a state of art review on various classes of small molecule inhibitors selectively involving PI3K/Akt/mTOR pathway and their clinical potential in this disease.

New Insights into Biology, Prognostic Factors, and Current Therapeutic Strategies in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is characterized by the clonal proliferation and accumulation of mature B lymphocytes. CLL cells show an antiapoptotic profile, suggesting the important role of apoptosis inhibition in the disease development. However, there is some population of proliferating CLL cells, which may also play a role in progression of the disease. There are several newer, biological prognostic factors in CLL. Currently, cytogenetic abnormalities with different prognostic values seem to be the most biologically relevant. During the last decades, the treatment of CLL has been significantly changed. Different strategies such as monotherapy with chlorambucil and purine nucleoside analogues (PNA) used alone or in combination with cyclophosphamide have been introduced. Most recently, immunochemotherapy with anti-CD20 monoclonal antibody, rituximab, combined with fludarabine and cyclophosphamide, became a gold standard of first-line treatment in eligible CLL patients. Currently, new treatment strategies including new monoclonal antibodies, bendamustine, lenalidomide, or inhibitors of several cell signaling pathways are under clinical studies in resistant/relapsed CLL patients. Moreover, allogeneic stem cell transplantation has to be considered, especially in younger high risk patients, for example, those who are resistant to PNA or those with 17p deletion. In this paper, we present the most important recent advances in CLL biology and treatment.

Helicobacter pylori infection, chronic inflammation, and genomic transformations in gastric MALT lymphoma.

Nowadays, it is believed that the main role in the development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma plays Helicobacter pylori infection. This world-wide distributed bacteria is in charge of most cases of not only upper gastrointestinal tract disorders but also some of extragastric problems. Constant stimulation of the immune system causes a B-lymphocytes proliferation, which is considered to be responsible for the neoplastic transformation. On the other hand, there are 10%–20% of patients who do not respond to Helicobacter pylori eradication treatment. This group has often a chromosome translocation, which suggests that there is another unknown, so far, pathogenetic mechanism of MALT lymphoma. Majority of genetic abnormalities are connected with nuclear factor-κB (NF-κB) pathway, which activates the uncontrolled proliferation of neoplastic cells. Translocations already described in studies are t(11;18)(q21;q21), which is the most common, t(14;18)(q32;q21), t(14;18)(q32;q21), and t(3;14)(p14.1;q32). This non-Hodgkins lymphoma is an indolent type originated outside lymph nodes. In more than 50% of cases, it occurs in the stomach. Occasionally, it can be found in salivary and thyroid gland, lung, breast, bladder, skin, or any other place in the human body. This paper is a review of the current knowledge on etiology, pathogenesis, treatment, and follow-up of gastric MALT lymphoma.

Pro-apoptotic effect of an anti-CD37 scFv-Fc fusion protein, in combination with the anti-CD20 antibody, ofatumumab, on tumour cells from B-cell malignancies

SMIP-016, a new anti-tumour agent, is a mouse/human chimeric fusion protein built on the ADAPTIR™ (modular protein therapeutic) platform targeting human CD37. In this study, for the first time, we examined pro-apoptotic activity of SMIP-016 in combination with monoclonal anti-CD20 antibody, ofatumumab (HuMax-CD20) in de novo chronic lymphocytic leukaemia (CLL) cells and in different B-cell neoplasm-derived lines. In CLL cells SMIP-016 exerted significant cytotoxicity (versus control - p=0.01). In the in vitro models, SMIP-016 was also distinctly active against Raji line (Burkitt lymphoma; BL) (versus control - p=0.007), Riva-1 line (diffuse large B-cell lymphoma; DLBCL) (versus control - p=0.002) and RPMI 8226 line (multiple myeloma cells; MM) (versus control - p=0.03). In studies combining SMIP-016 and ofatumumab, the cytotoxicity against CLL cells was significantly higher than the agents used alone (p<0.03). Remarkably enhanced cytotoxic activity of SMIP-016 and ofatumumab in combination was also observed in Raji and Riva-1 cell lines (p<0.01 and p<0.003, respectively). Importantly, both agents induced cytotoxicity at very low concentrations which suggests that potential side-effects may be decreased in clinical practice. The mechanism responsible for cytotoxicity of SMIP-016 in all the examined models was connected with caspase-dependent apoptosis. In majority of cell types SMIP-016 induced overexpression of Bax protein, as well as downregulation of Bcl-2, cIAP1 (p<0.03) and Smac/DIABLO (p<0.003) apoptosis-regulating proteins. In conclusion, our study demonstrated high pro-apoptotic activity of SMIP-016, especially in combination with ofatumumab, against ex vivo CLL cells, and BL or DLBCL in vitro cell lines. Thus, further preclinical studies in in vivo models are warranted, as this combination may be a promising therapeutic concept for treatment of those malignancies.

Cytotoxic activity of the amphibian ribonucleases onconase and r-amphinase on tumor cells from B cell lymphoproliferative disorders

Although major advancements in antitumor treatment have been observed, several B cell-derived malignancies still remain incurable. A promising approach that involves targeting RNA either by the use of specific antisense oligonucleotides or cytostatic/cytotoxic ribonucleases (RNases) is being promoted. Two amphibian RNases, onconase (ONC; ranpirnase) and, more recently, r-amphinase (r-Amph), have already been tested, but thus far, mostly on solid tumors. In this study, for the first time we provide comprehensive data on ex vivo and in vivo cytotoxic activity of ONC or r-Amph against cancer cells from different B cell lymphoid malignancies, together with their detailed mode of antitumor action. Our data revealed strong pro-apoptotic activity of ONC and r-Amph in both chronic lymphocytic leukemia and aggressive B cell lymphomas, with less impact on acute lymphoblastic leukemia or multiple myeloma cells. Moreover, the antitumor action of ONC and r-Amph was markedly selective against neoplastic cells sparing normal, healthy control‑derived lymphocytes.

Spontaneousin vitroapoptosis ofde novochronic lymphocytic leukemia cells correlates with risk of the disease progression: SpontaneousIn VitroApoptosis

Despite significant progress in treatment, chronic lymphocytic leukemia (CLL) still remains an incurable disease. Major advances have been recently made to understand the molecular pathogenesis underlying CLL, but defects in apoptosis are considered to be the most important factors. Although neoplastic cells are resistant to apoptosis in vivo, they show decreased level of spontaneous in vitro apoptosis, with significant differences among CLL patients. This work compares the level of spontaneous CLL cell apoptosis with prognostic factors and clinical course of the disease. In vitro spontaneous apoptosis of peripheral blood lymphocytes was analyzed using Annexin‐V assay (confirmed by TUNEL method) in 135 treatment naïve patients with CLL. Levels of apoptosis after 48 h culture in patients with stable disease were found to be significantly higher than in the group with progressive course of the disease (P = 0.015). Moreover, the level of spontaneous apoptosis after 24 and 48 h of incubation correlated inversely with the progression free survival (P = 0.026 and 0.009, respectively). These results suggest that in vitro spontaneous apoptosis of CLL cells may be a simple and cheap prognostic test which is relatively quick to use, and can predict the course of the disease and response to treatment.

Spontaneous in vitro apoptosis of de novo chronic lymphocytic leukemia cells correlates with risk of the disease progression

Despite significant progress in treatment, chronic lymphocytic leukemia (CLL) still remains an incurable disease. Major advances have been recently made to understand the molecular pathogenesis underlying CLL, but defects in apoptosis are considered to be the most important factors. Although neoplastic cells are resistant to apoptosis in vivo, they show decreased level of spontaneous in vitro apoptosis, with significant differences among CLL patients. This work compares the level of spontaneous CLL cell apoptosis with prognostic factors and clinical course of the disease. In vitro spontaneous apoptosis of peripheral blood lymphocytes was analyzed using Annexin-V assay (confirmed by TUNEL method) in 135 treatment naïve patients with CLL. Levels of apoptosis after 48h culture in patients with stable disease were found to be significantly higher than in the group with progressive course of the disease (p=0.015). Moreover, the level of spontaneous apoptosis after 24h and 48h of incubation correlated inversely with the progression free survival (p=0.026 and 0.009, respectively). These results suggest that in vitro spontaneous apoptosis of CLL cells may be a simple and cheap prognostic test which is relatively quick to use, and can predict the course of the disease and response to treatment.

In vitro cytotoxicity of ranpirnase (onconase) in combination with components of R-CHOP regimen against diffuse large B cell lymphoma (DLBCL) cell line.

Ranpirnase (onconase; ONC) is an endoribonuclease obtained from the frog Rana pipiens. This enzyme exhibits anticancer properties mediated by degradation of cellular RNA and induction of apoptosis. In this study we assessed cytotoxicity of ONC in combination with currently used anticancer drugs on a human diffuse large B-cell lymphoma (DLBCL)-derived cell line (Toledo). Cytotoxic activity was measured by the exclusion of propidium iodide assay while apoptosis was assessed using the annexin-V binding method. Additionally, flow cytometry was used to assess the decline of mitochondrial potential and to determine activation of caspases 3, 8 and 9. It was observed that in vitro treatment with ONC in combination with rituximab, mafosfamide, vincristine, doxorubicin, and dexamethasone (drugs corresponding with elements of R-CHOP regimen) resulted in increased cytotoxicity. As a result ONC showed marked cytotoxicity against Toledo cells. Importantly, in combination of ONC with drugs imitating the R-CHOP regimen, this effect was significantly intensified. The main mechanism responsible for this event was induction of apoptosis along a mitochondrial dependent pathway. In conclusion, these data indicate that further preclinical and eventually clinical studies assessing activity of ONC+R-CHOP treatment are warranted.

Treatment options for mantle cell lymphoma

Introduction: In this article, we provide an accurate overview of both standard treatment option and novel promising therapeutics. Major impact is on novel agents now being tested in randomized clinical trials. While the initial data are promising, they may rapidly expand treatment options, change existing paradigms and further improve outcomes for mantle cell lymphoma (MCL) patients. Areas covered: MCL is a disease with indolent histology, but aggressive clinical course. However, for now, MCL remains incurable and the search for the most effective and tumor-specific treatment still represents a great challenge for oncohematologists. However, the implementation of chemotherapy together with the anti-CD20 antibody rituximab, as well as the growing use of autologous stem cell transplantation in first remission, have improved effects of treatment in MCL, including even some improvement in overall survival. Recently, treatment modalities for MCL have been expanded by strategies based on several biologically targeted agents, including m-TOR kinase or proteasome inhibitors and immunomodulatory agents, such as lenalidomide. B-cell receptor pathway inhibitors, such as ibrutinib and idelalisib, and histone deacetylase or cyclin-dependent kinase inhibitors have also shown promising activity in resistant or relapsed disease. Expert opinion: Although enormous progress was made in the treatment of MCL over the last year, the disease remains incurable. One chance for the significant life prolongation is intensive treatment with consolidative auto SCT. However, real progress may be afforded by developing the novel agents described in this article. In this way, MCL may soon become another potentially curable oncological malignancy.

The Role of Radiotherapy in Hodgkin’s Lymphoma: What Has Been Achieved during the Last 50 Years?

Currently, Hodgkins lymphoma (HL) has an excellent clinical outcome, with overall survival of approximately 90% in early stages of the disease. Based on young age of the majority of patients at the time of diagnosis and their long survival time, increased attention has been focused on long-term toxicity of therapy. While novel, directly targeting antitumor agents, with an excellent safety profile, have been developed for HL treatment, the role of radiotherapy is still debated. Radiotherapy may induce cardiovascular disease and impairment of thyroid or pulmonary function and, most importantly, may lead to development of secondary cancers. As a consequence, the current radiation therapy planning paradigm is mainly focused on a reduction of field size. As it was investigated in clinical trials regional therapy is as effective as extended field radiotherapy, but less toxic. Although chemotherapy is the mainstay of HL treatment, consolidative involved field radiation therapy is still considered to be the standard of care in both early and advanced stages. Recently, further field reduction has been investigated to further decrease the late radiation-induced toxicity. In this paper we describe the role and safety profile of radiotherapy in the past and present and hope for the novel techniques in the future.