Rabbit Anti T-Lymphocyte Globulin Induces Apoptosis in Peripheral Blood Mononuclear Cell Compartments and Leukemia Cells, While Hematopoetic Stem Cells Are Apoptosis Resistant

AbstractPolyclonal anti-T-lymphocyte globulins (ATG) are used in allogeneic stem cell transplantation (SCT) for the prophylaxis of graft versus host disease (GVHD) by in vivo T cell depletion. In this study we investigated the complement independent induction of apoptosis by rabbit ATG in peripheral blood mononuclear cell (PBMNC) compartments and hematopoetic stem cells (HSC). We also detected antileukemic activity of ATG by measuring apoptosis in myeloid and lymphatic leukemia cell lines and primary leukemia cells. We found ATG to induce apoptosis in T-lymphocytes (CD4+, CD8+), B-lymphocytes (CD20+), natural killer (NK)-cells (CD56+), and monocytes (CD14+). HSC, in contrast, were apoptosis resistant and could be growth stimulated by low-dose ATG in the presence of bystander cells. The human leukemia cell lines Jurkat, Daudi, DG-75 (lymphoblastic), and K562, HL-60, KG1, and U937 (myeloblastic) underwent ATG-induced apoptosis, whereas the NK-cell line YT was resistant. Primary leukemia cells from 6 investigated patients with acute lymphoblastic leukemia, 9 of 10 patients with chronic lymphocytic leukemia, and 4 of 8 patients with acute myeloblastic leukemia underwent ATG-induced apoptosis. We conclude apoptosis induction in all PBMNC compartments contributes to GVHD prophylaxis. ATG might support engraftment. Finally, antileukemic activity of ATG could positively influence the transplantation outcome

Marrow versus Blood-Derived Stem Cell Grafts for Allogeneic Transplantation from Unrelated Donors in Patients with Active Myeloid Leukemia or Myelodysplasia

Peripheral blood stem cells (PBSCs) are increasingly used as the graft source in allogeneic hematopoietic cell transplantation. We compared long-term outcome after unrelated donor transplantation of 85 consecutive patients with acute myelogenous leukemia or myelodysplastic syndrome regarding disease status (early disease [CR1, refractory anemia); n = 25 and advanced/active disease [>CR1, >refractory anemia]; n = 60) who were treated with conventional conditioning regimens followed by bone marrow (BM) or PBSC grafts. Graft-versus-host disease prophylaxis consisted mainly of cyclosporine A, short-course methotrexate, and anti-T-lymphocyte globulin. After a median follow-up of 118 months (68-174), the 10-year event-free survival rate after peripheral blood stem cell transplantation (PBSCT) was 54.8% (95% confidence interval [CI], 39.7%-69.8%), and after bone marrow transplantation (BMT), it was 27.9% (14.5%-41.3%; P < .004). In the advanced/active disease group, the 10-year event-free survival rate after PBSCT was 50% (30.8%-69.2%), and after BMT, it was 23.5% (9.3%-37.8%; P < .007). Non relapse mortality was less after PBSCT than BMT (14.3% vs 30.2%), respectively. In multivariate Cox regression analysis, PBSCT showed a better overall survival (OS; hazard ratio [HR], 0.43; 95% CI, 0.23-0.79; P = .007) compared to BMT; unfavorable/unknown prognostic impact cytogenetic abnormalities were an adverse factor for all patients (HR, 2.202; 95% CI, 1.19-4.06; P = .011). In patients with advanced disease, the use of PBSCs showed a significant favorable outcome via multivariate analysis (HR, 0.49; 95% CI, 0.24-0.99; P = .046). Outcome of acute myelogenous leukemia/myelodysplastic syndrome after unrelated hematopoietic cell transplantation is adversely affected by cytogenetic abnormalities and state of remission at hematopoietic cell transplantation. PBSC as a graft source has a significant favorable influence on survival

Systemic treatment of advanced/metastatic renal cell carcinoma in the context of SARS-CoV-2 pandemic: recommendations from the interdisciplinary working group for renal tumors (IAG-N)

Abstract This letter summarizes recommendations from the interdisciplinary working group of renal tumors (IAGN) of the German Cancer Society for the systemic treatment of advanced/metastatic renal cell carcinoma in the context of the current SARS-CoV-2 pandemi

Harnessing the p53-PUMA Axis to Overcome DNA Damage Resistance in Renal Cell Carcinoma

Resistance to DNA damage–induced apoptosis is a hallmark of cancer and a major cause of treatment failure and lethal disease outcome. A tumor entity that is largely resistant to DNA-damaging therapies including chemo- or radiotherapy is renal cell carcinoma (RCC). This study was designed to explore the underlying molecular mechanisms of DNA damage resistance in RCC to develop strategies to resensitize tumor cells to DNA damage–induced apoptosis. Here, we show that apoptosis-resistant RCC cells have a disconnect between activation of p53 and upregulation of the downstream proapoptotic protein p53 upregulated modulator of apoptosis (PUMA). We demonstrate that this disconnect is not caused by gene-specific repression through CCCTC-binding factor (CTCF) but instead by aberrant chromatin compaction. Treatment with an HDAC inhibitor was found to effectively reactivate PUMA expression on the mRNA and protein level and to revert resistance to DNA damage–induced cell death. Ectopic expression of PUMA was found to resensitize a panel of RCC cell lines to four different DNA-damaging agents tested. Remarkably, all RCC cell lines analyzed were wild-type for p53, and a knockdown was likewise able to sensitize RCC cells to acute genotoxic stress. Taken together, our results indicate that DNA damage resistance in RCC is reversible, involves the p53-PUMA axis, and is potentially targetable to improve the oncological outcomes of RCC patients

Patient expectations are better for immunotherapy than traditional chemotherapy for cancer

Purpose!#!The main aim of the study was to explore the expectations and knowledge of advanced-stage cancer patients about immunotherapy.!##!Methods!#!This mixed methods study included 53 cancer patients on immune checkpoint inhibitors (ICIs), 55 cancer patients undergoing chemotherapy (CT), and 53 non-cancer patients. Participants' expectations about ICIs and CT were compared. Additional qualitative data were derived from semi-structured interviews.!##!Results!#!Among patients who did not receive ICIs, 63 (58%) had never heard of ICIs and 94 (87%) had large gaps in their knowledge of ICIs. Among ICI patients, 33 (62%) simply described ICIs without errors. ICI perception was positive, regardless of whether respondents received or had heard of ICIs, which became particularly evident when compared to CT. ICIs were rated as more promising, and all adverse effects were expected to be significantly lower than those of CT. Knowledge about ICIs was also limited in the interviewed ICI patients. Some patients reported adverse effects of ICIs that were mostly mild and well-tolerated or easily treated.!##!Conclusions!#!The lack of understanding of ICIs should be improved by activities to increase the knowledge of ICI patients and the general population. In contrast to CT, ICIs invoked fewer negative associations with efficacy and toxicity. Therefore, attention should be paid to risk awareness when educating patients. (Clinical trial registration number: DRKS00011868) Trial Registration: German clinical trials register, www.germanctr.de , number DRKS00011868