scholarly journals Cell Death after Photodynamic Therapy Treatment in Unicellular Protozoan Parasite Tritrichomonas foetus

2020 ◽  
Author(s):  
Newton Soares da Silva ◽  
Aline Margraf Ferreira ◽  
Carolina Weigert Galvão ◽  
Rafael Mazer Etto ◽  
Cristina Pacheco Soares
Keyword(s):  
Cell Death ◽  
Photodynamic Therapy ◽  
Programmed Cell Death ◽  
Protozoan Parasite ◽  
Future Research ◽  
Tritrichomonas Foetus ◽  
Cellular Death ◽  
Nuclear Abnormalities ◽  
Cell Changes ◽  
Therapy Treatment

Programmed cell death in T. foetus does not seem to make sense at first sight; however, different mechanisms of cellular death in this unicellular organism have been observed. This review summarizes the available data related to programmed cell death already published for the cattle parasite T. foetus and attempts to clarify some crucial points to understand this mechanism found in non-mitochondriates parasites, as well as assist in future research. Important results with different treatments showed that the T. foetus can choose among different pathways how to initiate cell death. Thus, a major challenge for cellular death research remains the identification of the molecular cell death machinery of this protist, such as caspases pathway, nuclear abnormalities, morphology cell changes, cellular death in this parasite and the prospects in the future research. Although, the possibility of the existence of different pathways to cell death in trichomonads is discussed and a model for possible executioners pathways during T. foetus cell death is proposed.

scholarly journals Calcium Signaling in Plant Programmed Cell Death

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1089
Author(s):  
Huimin Ren ◽  
Xiaohong Zhao ◽  
Wenjie Li ◽  
Jamshaid Hussain ◽  
Guoning Qi ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Abiotic Stresses ◽  
Animal Studies ◽  
Future Research ◽  
Significant Progress ◽  
Biotic And Abiotic Stresses ◽  
Stress Perception ◽  
The Past

Programmed cell death (PCD) is a process intended for the maintenance of cellular homeostasis by eliminating old, damaged, or unwanted cells. In plants, PCD takes place during developmental processes and in response to biotic and abiotic stresses. In contrast to the field of animal studies, PCD is not well understood in plants. Calcium (Ca2+) is a universal cell signaling entity and regulates numerous physiological activities across all the kingdoms of life. The cytosolic increase in Ca2+ is a prerequisite for the induction of PCD in plants. Although over the past years, we have witnessed significant progress in understanding the role of Ca2+ in the regulation of PCD, it is still unclear how the upstream stress perception leads to the Ca2+ elevation and how the signal is further propagated to result in the onset of PCD. In this review article, we discuss recent advancements in the field, and compare the role of Ca2+ signaling in PCD in biotic and abiotic stresses. Moreover, we discuss the upstream and downstream components of Ca2+ signaling and its crosstalk with other signaling pathways in PCD. The review is expected to provide new insights into the role of Ca2+ signaling in PCD and to identify gaps for future research efforts.

Metronidazole induces programmed cell death in the protozoan parasite Blastocystis hominis

Microbiology ◽  
2004 ◽  
Vol 150 (1) ◽  
pp. 33-43 ◽  
Author(s):  
A. M. A. Nasirudeen ◽  
Yap Eu Hian ◽  
Mulkit Singh ◽  
Kevin S. W. Tan
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Protozoan Parasite ◽  
Blastocystis Hominis

Efficacy of PD-1 or PD-L1 inhibitors and central nervous system metastases in advanced cancer: a meta-analysis

2021 ◽  
Vol 21 ◽  
Author(s):  
Minyong Peng ◽  
Shan Li ◽  
Hui Xiang ◽  
Wen Huang ◽  
Weiling Mao ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Overall Survival ◽  
Cell Death ◽  
Nervous System ◽  
Programmed Cell Death ◽  
Future Research ◽  
Significant Heterogeneity ◽  
Cns Metastases ◽  
Hazard Ratios ◽  
Significant Difference

<P>Background: Little is known about the efficacy of programmed cell death protein-1 (PD-1) or programmed cell death-ligand 1 (PD-L1) inhibitors in patients with central nervous system (CNS) metastases. <P> Objective: Assess the difference in efficacy of PD-1 or PD-L1 inhibitors in patients with and without CNS metastases. <P> Methods: From inception to March 2020, PubMed and Embase were searched for randomized controlled trials (RCTs) about PD-1 or PD-L1 inhibitors. Only trails with available hazard ratios (HRs) for overall survival (OS) of patients with and without CNS metastases simultaneously would be included. Overall survival hazard ratios and their 95% confidence interval (CI) were calculated, and the efficacy difference between these two groups was assessed in the meantime. <P> Results: 4988 patients (559 patients with CNS metastases and 4429 patients without CNS metastases) from 8 RCTs were included. In patients with CNS metastases, the pooled HR was 0.76 (95%CI, 0.62 to 0.93), while in patients without CNS metastases, the pooled HR was 0.74 (95%CI, 0.68 to 0.79). There was no significant difference in efficacy between these two groups (Χ=0.06 P=0.80). <P> Conclusion: With no significant heterogeneity observed between patients with or without CNS metastases, patients with CNS metastases should not be excluded from PD-1 or PD-L1 blockade therapy. Future research should permit more patients with CNS metastases to engage in PD-1 or PD-L1 blockade therapy and explore the safety of PD-1 or PD-L1 inhibitors in patients with CNS metastases.</P>

scholarly journals Characterization of Metacaspases with Trypsin-Like Activity and Their Putative Role in Programmed Cell Death in the Protozoan Parasite Leishmania

2007 ◽  
Vol 6 (10) ◽  
pp. 1745-1757 ◽  
Author(s):  
Nancy Lee ◽  
Sreenivas Gannavaram ◽  
Angamuthu Selvapandiyan ◽  
Alain Debrabant
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Leishmania Donovani ◽  
Protozoan Parasite ◽  
Protein Band ◽  
Mrna Levels ◽  
Enzymatic Assays ◽  
Rich Domain ◽  
Axenic Amastigotes

ABSTRACT In this report, we have characterized two metacaspases of Leishmania donovani, L. donovani metacaspase-1 (LdMC1) and LdMC2. These two proteins show 98% homology with each other, and both contain a characteristic C-terminal proline-rich domain. Both genes are transcribed in promastigotes and axenic amastigotes of L. donovani; however, LdMC1 shows increased mRNA levels in axenic amastigotes. An anti-LdMC antibody was obtained and showed reactivity with a single ∼42-kDa protein band in both promastigote and axenic amastigote parasite whole-cell lysates by Western blotting. Pulse-chase experiments suggest that LdMCs are not synthesized as proenzymes, and immunofluorescence studies show that LdMCs are associated with the acidocalcisome compartments of L. donovani. Enzymatic assays of immunoprecipitated LdMCs show that native LdMCs efficiently cleave trypsin substrates and are unable to cleave caspase-specific substrates. Consistently, LdMC activity is insensitive to caspase inhibitors and is efficiently inhibited by trypsin inhibitors, such as leupeptin, antipain, and N α-tosyl-l-lysine-chloromethyl ketone (TLCK). In addition, our results show that LdMC activity was induced in parasites treated with hydrogen peroxide, a known trigger of programmed cell death (PCD) in Leishmania and that parasites overexpressing metacaspases are more sensitive to hydrogen peroxide-induced PCD. These findings suggest that Leishmania metacaspases are not responsible for the caspase-like activities reported in this organism and suggest a possible role for LdMCs as effector molecules in Leishmania PCD.

PHOTODYNAMIC THERAPY WITH PHOTOFRIN II INDUCES PROGRAMMED CELL DEATH IN CARCINOMA CELL LINES

1994 ◽  
Vol 59 (4) ◽  
pp. 468-473 ◽  
Author(s):  
Xiao-Yan He ◽  
Robert A. Sikes ◽  
Sharon Thomsen ◽  
Leland W. K. Chung ◽  
Steven L. Jacques
Keyword(s):  
Cell Death ◽  
Photodynamic Therapy ◽  
Programmed Cell Death ◽  
Cell Lines ◽  
Carcinoma Cell ◽  
Photofrin Ii ◽  
Carcinoma Cell Lines

Ethylene and programmed cell death in plants

Botany ◽  
2009 ◽  
Vol 87 (8) ◽  
pp. 757-769 ◽  
Author(s):  
Christopher P. Trobacher
Keyword(s):  
Signal Transduction ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Adventitious Roots ◽  
Future Research ◽  
Aerenchyma Formation ◽  
Gaseous Hydrocarbon ◽  
Reproductive Structures ◽  
Ethylene Signalling ◽  
Ethylene Signal

Plants produce and utilize the gaseous hydrocarbon ethylene as a phytohormone throughout their life cycle. Ethylene is notoriously associated with fruit ripening and this aspect of its biology, along with its biosynthesis and mechanisms of signal transduction, has received a great deal of study. Many plants also employ ethylene signalling during instances of programmed cell death (PCD), including aerenchyma formation, epidermal PCD above emerging adventitious roots, senescence of petals, leaves, and reproductive structures, and endosperm death in developing cereal seeds. Ethylene-signalling during PCD is both spatially and temporally regulated, and is selective in that it induces PCD only in sensitized cells or tissues. This review examines instances of ethylene-regulated plant PCD, proposes a general model, and suggests avenues for future research that might improve our understanding of both PCD and ethylene signal transduction.

scholarly journals Immunotherapy for hepatocellular carcinoma: recent advances and future perspectives

2019 ◽  
Vol 11 ◽  
pp. 175883591986269 ◽  
Author(s):  
Weiqi Xu ◽  
Ken Liu ◽  
Minjiang Chen ◽  
Jin-Yu Sun ◽  
Geoffrey W McCaughan ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Phase I ◽  
Checkpoint Inhibitors ◽  
Killer Cell ◽  
Objective Response ◽  
Phase Iii ◽  
Future Research ◽  
Advanced Hcc

The introduction of immunotherapies has been a major development in the treatment of many advanced cancers, including hepatocellular carcinoma (HCC). We are entering a new era of systemic therapy for advanced HCC associated with an explosion of clinical trial activity. Data from phase I/II studies of checkpoint inhibitors in advanced HCC have been promising, with durable objective response rates of approximately 20% seen (in both first- and second-line settings) and acceptable safety profiles (including immune-mediated hepatitis). Phase III studies evaluating anti-programmed cell death protein 1 (anti-PD-1) and anti-programmed cell death ligand 1 (anti-PD-L1) antibodies compared with sorafenib are already underway. The potential synergistic effects of anti-PD-1/anti-PD-L1 when used in combination with agents against other checkpoint molecules, systemic therapies, as well as conventional surgical and locoregional therapies are also being explored in upcoming clinical trials. Aside from this, other strategies to harness the immune system, including chimeric antigen receptor-engineered T cells, natural killer cell therapies, and peptide vaccines directed against HCC antigens have entered phase I/II studies. Current limitations of immunotherapies and areas of future research include the accurate assessment and prediction of tumor response, overcoming the immunosuppressive effects of a hypoxic microenvironment, and the management of immune-related hepatitis in patients who already have limited liver reserve.

scholarly journals Programmed cell death in the unicellular protozoan parasite Leishmania

2002 ◽  
Vol 9 (1) ◽  
pp. 53-64 ◽  
Author(s):  
N Lee ◽  
S Bertholet ◽  
A Debrabant ◽  
J Muller ◽  
R Duncan ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Protozoan Parasite ◽  
Parasite Leishmania
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