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Chinese Journal of Cancer Jun 2017Multidrug resistance (MDR) occurs frequently after long-term chemotherapy, resulting in refractory cancer and tumor recurrence. Therefore, combatting MDR is an important... (Review)
Review
Multidrug resistance (MDR) occurs frequently after long-term chemotherapy, resulting in refractory cancer and tumor recurrence. Therefore, combatting MDR is an important issue. Autophagy, a self-degradative system, universally arises during the treatment of sensitive and MDR cancer. Autophagy can be a double-edged sword for MDR tumors: it participates in the development of MDR and protects cancer cells from chemotherapeutics but can also kill MDR cancer cells in which apoptosis pathways are inactive. Autophagy induced by anticancer drugs could also activate apoptosis signaling pathways in MDR cells, facilitating MDR reversal. Therefore, research on the regulation of autophagy to combat MDR is expanding and is becoming increasingly important. We summarize advanced studies of autophagy in MDR tumors, including the variable role of autophagy in MDR cancer cells.
Topics: Antineoplastic Agents; Apoptosis; Autophagy; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Neoplasms
PubMed: 28646911
DOI: 10.1186/s40880-017-0219-2 -
Nature Reviews. Neurology Jan 2021Progressive multifocal leukoencephalopathy (PML) is a devastating CNS infection caused by JC virus (JCV), a polyomavirus that commonly establishes persistent,... (Review)
Review
Progressive multifocal leukoencephalopathy (PML) is a devastating CNS infection caused by JC virus (JCV), a polyomavirus that commonly establishes persistent, asymptomatic infection in the general population. Emerging evidence that PML can be ameliorated with novel immunotherapeutic approaches calls for reassessment of PML pathophysiology and clinical course. PML results from JCV reactivation in the setting of impaired cellular immunity, and no antiviral therapies are available, so survival depends on reversal of the underlying immunosuppression. Antiretroviral therapies greatly reduce the risk of HIV-related PML, but many modern treatments for cancers, organ transplantation and chronic inflammatory disease cause immunosuppression that can be difficult to reverse. These treatments - most notably natalizumab for multiple sclerosis - have led to a surge of iatrogenic PML. The spectrum of presentations of JCV-related disease has evolved over time and may challenge current diagnostic criteria. Immunotherapeutic interventions, such as use of checkpoint inhibitors and adoptive T cell transfer, have shown promise but caution is needed in the management of immune reconstitution inflammatory syndrome, an exuberant immune response that can contribute to morbidity and death. Many people who survive PML are left with neurological sequelae and some with persistent, low-level viral replication in the CNS. As the number of people who survive PML increases, this lack of viral clearance could create challenges in the subsequent management of some underlying diseases.
Topics: Adoptive Transfer; Humans; Immune Checkpoint Inhibitors; JC Virus; Leukoencephalopathy, Progressive Multifocal; T-Lymphocytes
PubMed: 33219338
DOI: 10.1038/s41582-020-00427-y -
Immunity Jan 2019Checkpoint blockade mediates a proliferative response of tumor-infiltrating CD8 T lymphocytes (TILs). The origin of this response has remained elusive because chronic...
Checkpoint blockade mediates a proliferative response of tumor-infiltrating CD8 T lymphocytes (TILs). The origin of this response has remained elusive because chronic activation promotes terminal differentiation or exhaustion of tumor-specific T cells. Here we identified a subset of tumor-reactive TILs bearing hallmarks of exhausted cells and central memory cells, including expression of the checkpoint protein PD-1 and the transcription factor Tcf1. Tcf1PD-1 TILs mediated the proliferative response to immunotherapy, generating both Tcf1PD-1 and differentiated Tcf1PD-1 cells. Ablation of Tcf1PD-1 TILs restricted responses to immunotherapy. Tcf1 was not required for the generation of Tcf1PD-1 TILs but was essential for the stem-like functions of these cells. Human TCF1PD-1 cells were detected among tumor-reactive CD8 T cells in the blood of melanoma patients and among TILs of primary melanomas. Thus, immune checkpoint blockade relies not on reversal of T cell exhaustion programs, but on the proliferation of a stem-like TIL subset.
Topics: Animals; Antibodies, Monoclonal; CD8-Positive T-Lymphocytes; Cell Differentiation; Cell Proliferation; Hepatitis A Virus Cellular Receptor 2; Hepatocyte Nuclear Factor 1-alpha; Humans; Immunotherapy; Lymphocytes, Tumor-Infiltrating; Melanoma; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Programmed Cell Death 1 Receptor; Stem Cells; T-Lymphocyte Subsets
PubMed: 30635237
DOI: 10.1016/j.immuni.2018.12.021 -
International Journal of Molecular... Nov 2020The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay detects DNA breakage by labeling the free 3'-hydroxyl termini. Given that genomic... (Review)
Review
The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay detects DNA breakage by labeling the free 3'-hydroxyl termini. Given that genomic DNA breaks arise during early and late stages of apoptosis, TUNEL staining continues to be widely used as a measure of apoptotic cell death. The advantages of the assay include its relative ease of performance and the broad availability of TUNEL assay kits for various applications, such as single-cell analysis of apoptosis in cell cultures and tissue samples. However, as briefly discussed herein, aside from some concerns relating to the specificity of the TUNEL assay itself, it was demonstrated some twenty years ago that the early stages of apoptosis, detected by TUNEL, can be reversed. More recently, compelling evidence from different biological systems has revealed that cells can recover from even late stage apoptosis through a process called anastasis. Specifically, such recovery has been observed in cells exhibiting caspase activation, genomic DNA breakage, phosphatidylserine externalization, and formation of apoptotic bodies. Furthermore, there is solid evidence demonstrating that apoptotic cells can promote neighboring tumor cell repopulation (e.g., through caspase-3-mediated secretion of prostaglandin E) and confer resistance to anticancer therapy. Accordingly, caution should be exercised in the interpretation of results obtained by the TUNEL and other apoptosis assays (e.g., caspase activation) in terms of apoptotic cell demise.
Topics: Animals; Antineoplastic Agents; Apoptosis; Biological Assay; DNA Breaks; Humans; In Situ Nick-End Labeling; Neoplasms
PubMed: 33260475
DOI: 10.3390/ijms21239090 -
Cell Death and Differentiation Feb 2021The BAP1 gene has emerged as a major tumor suppressor mutated with various frequencies in numerous human malignancies, including uveal melanoma, malignant pleural... (Review)
Review
The BAP1 gene has emerged as a major tumor suppressor mutated with various frequencies in numerous human malignancies, including uveal melanoma, malignant pleural mesothelioma, clear cell renal cell carcinoma, intrahepatic cholangiocarcinoma, hepatocellular carcinoma, and thymic epithelial tumors. BAP1 mutations are also observed at low frequency in other malignancies including breast, colorectal, pancreatic, and bladder cancers. BAP1 germline mutations are associated with high incidence of mesothelioma, uveal melanoma, and other cancers, defining the "BAP1 cancer syndrome." Interestingly, germline BAP1 mutations constitute an important paradigm for gene-environment interactions, as loss of BAP1 predisposes to carcinogen-induced tumorigenesis. Inactivating mutations of BAP1 are also identified in sporadic cancers, denoting the importance of this gene for normal tissue homeostasis and tumor suppression, although some oncogenic properties have also been attributed to BAP1. BAP1 belongs to the deubiquitinase superfamily of enzymes, which are responsible for the maturation and turnover of ubiquitin as well as the reversal of substrate ubiquitination, thus regulating ubiquitin signaling. BAP1 is predominantly nuclear and interacts with several chromatin-associated factors, assembling multi-protein complexes with mutually exclusive partners. BAP1 exerts its function through highly regulated deubiquitination of its substrates. As such, BAP1 orchestrates chromatin-associated processes including gene expression, DNA replication, and DNA repair. BAP1 also exerts cytoplasmic functions, notably in regulating Ca signaling at the endoplasmic reticulum. This DUB is also subjected to multiple post-translational modifications, notably phosphorylation and ubiquitination, indicating that several signaling pathways tightly regulate its function. Recent progress indicated that BAP1 plays essential roles in multiple cellular processes including cell proliferation and differentiation, cell metabolism, as well as cell survival and death. In this review, we summarize the biological and molecular functions of BAP1 and explain how the inactivation of this DUB might cause human cancers. We also highlight some of the unresolved questions and suggest potential new directions.
Topics: Animals; Cell Death; Cell Proliferation; Gene-Environment Interaction; Germ-Line Mutation; Humans; Neoplasms; Protein Processing, Post-Translational; Tumor Suppressor Proteins; Ubiquitin Thiolesterase
PubMed: 33462414
DOI: 10.1038/s41418-020-00709-4 -
International Journal of Molecular... Oct 2021Until recently, radiation effects have been considered to be mainly due to nuclear DNA damage and their management by repair mechanisms. However, molecular biology... (Review)
Review
Until recently, radiation effects have been considered to be mainly due to nuclear DNA damage and their management by repair mechanisms. However, molecular biology studies reveal that the outcomes of exposures to ionizing radiation (IR) highly depend on activation and regulation through other molecular components of organelles that determine cell survival and proliferation capacities. As typical epigenetic-regulated organelles and central power stations of cells, mitochondria play an important pivotal role in those responses. They direct cellular metabolism, energy supply and homeostasis as well as radiation-induced signaling, cell death, and immunological responses. This review is focused on how energy, dose and quality of IR affect mitochondria-dependent epigenetic and functional control at the cellular and tissue level. Low-dose radiation effects on mitochondria appear to be associated with epigenetic and non-targeted effects involved in genomic instability and adaptive responses, whereas high-dose radiation effects (>1 Gy) concern therapeutic effects of radiation and long-term outcomes involving mitochondria-mediated innate and adaptive immune responses. Both effects depend on radiation quality. For example, the increased efficacy of high linear energy transfer particle radiotherapy, e.g., C-ion radiotherapy, relies on the reduction of anastasis, enhanced mitochondria-mediated apoptosis and immunogenic (antitumor) responses.
Topics: Epigenesis, Genetic; Epithelial-Mesenchymal Transition; Genomic Instability; Humans; Mitochondria; Mitochondrial Dynamics; Oxidative Stress; Radiation, Ionizing; Reactive Oxygen Species; Signal Transduction
PubMed: 34681703
DOI: 10.3390/ijms222011047 -
Cell Reports May 2022The MDM2 oncoprotein antagonizes the tumor suppressor p53 by physical interaction and ubiquitination. However, it also sustains the progression of DNA replication forks,...
The MDM2 oncoprotein antagonizes the tumor suppressor p53 by physical interaction and ubiquitination. However, it also sustains the progression of DNA replication forks, even in the absence of functional p53. Here, we show that MDM2 binds, inhibits, ubiquitinates, and destabilizes poly(ADP-ribose) polymerase 1 (PARP1). When cellular MDM2 levels are increased, this leads to accelerated progression of DNA replication forks, much like pharmacological inhibition of PARP1. Conversely, overexpressed PARP1 restores normal fork progression despite elevated MDM2. Strikingly, MDM2 profoundly reduces the frequency of fork reversal, revealed as four-way junctions through electron microscopy. Depletion of RECQ1 or the primase/polymerase (PRIMPOL) reverses the MDM2-mediated acceleration of the nascent DNA elongation rate. MDM2 also increases the occurrence of micronuclei, and it exacerbates camptothecin-induced cell death. In conclusion, high MDM2 levels phenocopy PARP inhibition in modulation of fork restart, representing a potential vulnerability of cancer cells.
Topics: DNA; DNA Damage; DNA Primase; DNA Replication; Tumor Suppressor Protein p53
PubMed: 35649362
DOI: 10.1016/j.celrep.2022.110879 -
Kidney International Jun 2009Renal fibrosis is the hallmark of progressive renal disease of virtually any etiology. The model of unilateral ureteral obstruction (UUO) in the rodent generates... (Review)
Review
Renal fibrosis is the hallmark of progressive renal disease of virtually any etiology. The model of unilateral ureteral obstruction (UUO) in the rodent generates progressive renal fibrosis. Surgically created UUO can be experimentally manipulated with respect to timing, severity, and duration, while reversal of the obstruction permits the study of recovery. The use of genetically engineered mice has greatly expanded the utility of the model in studying molecular mechanisms underlying the renal response to UUO. Ureteral obstruction results in marked renal hemodynamic and metabolic changes, followed by tubular injury and cell death by apoptosis or necrosis, with interstitial macrophage infiltration. Proliferation of interstitial fibroblasts with myofibroblast transformation leads to excess deposition of the extracellular matrix and renal fibrosis. Phenotypic transition of resident renal tubular cells, endothelial cells, and pericytes has also been implicated in this process. Technical aspects of the UUO model are discussed in this review, including the importance of rodent species or strain, the age of the animal, surgical procedures, and histological methods. The UUO model is likely to reveal useful biomarkers of progression of renal disease, as well as new therapies, which are desperately needed to allow intervention before the establishment of irreversible renal injury.
Topics: Animals; Disease Models, Animal; Fibrosis; Kidney Diseases; Mice; Ureteral Obstruction
PubMed: 19340094
DOI: 10.1038/ki.2009.86 -
Cell Communication and Signaling : CCS Jun 2022Balanced cell death and survival are among the most important cell development and homeostasis pathways that can play a critical role in the onset or progress of... (Review)
Review
Balanced cell death and survival are among the most important cell development and homeostasis pathways that can play a critical role in the onset or progress of malignancy steps. Anastasis is a natural cell recovery pathway that rescues cells after removing the apoptosis-inducing agent or brink of death. The cells recuperate and recover to an active and stable state. So far, minimal knowledge is available about the molecular mechanisms of anastasis. Still, several involved pathways have been explained: recovery through mitochondrial outer membrane permeabilization, caspase cascade arrest, repairing DNA damage, apoptotic bodies formation, and phosphatidylserine. Anastasis can facilitate the survival of damaged or tumor cells, promote malignancy, and increase drug resistance and metastasis. Here, we noted recently known mechanisms of the anastasis process and underlying molecular mechanisms. Additionally, we summarize the consequences of anastatic mechanisms in the initiation and progress of malignancy, cancer cell metastasis, and drug resistance. Video Abstract.
Topics: Apoptosis; Cell Death; Cell Death Reversal; Cell Survival; DNA Damage; Humans; Neoplasms
PubMed: 35659306
DOI: 10.1186/s12964-022-00880-w -
Liver Cancer Jul 2021Reversal of CD8 T-cell exhaustion was considered a major antitumor mechanism of anti-programmed cell death-1 (PD-1)/ anti-programmed death ligand-1 (PD-L1)-based immune...
BACKGROUND
Reversal of CD8 T-cell exhaustion was considered a major antitumor mechanism of anti-programmed cell death-1 (PD-1)/ anti-programmed death ligand-1 (PD-L1)-based immune checkpoint inhibitor (ICI) therapy.
OBJECTIVES
The aim of this study was to identify markers of T-cell exhaustion that is best associated with ICI treatment efficacy for advanced hepatocellular carcinoma (HCC).
METHODS
Immune cell composition of archival tumor samples was analyzed by transcriptomic analysis and multiplex immunofluorescence staining.
RESULTS
HCC patients with objective response after anti-PD-1/anti-PD-L1-based ICI therapy ( = 42) had higher expression of genes related to T-cell exhaustion. A 9-gene signature (LAG3, CD244, CCL5, CXCL9, CXCL13, MSR1, CSF3R, CYBB, and KLRK1) was defined, whose expression was higher in patients with response to ICI therapy, correlated with density of CD8LAG3 cells in tumor microenvironment, and independently predicted better progression-free and overall survival. This 9-gene signature had similar predictive values for patients who received single-agent or combination ICI therapy and was not associated with prognosis in HCC patients who received surgery, suggesting that it may outperform other T-cell signatures for predicting efficacy of ICI therapy for HCC. For HCC patients who underwent surgery for both the primary liver and metastatic lung tumors ( = 31), lung metastatic HCC was associated with a higher exhausted CD8 T-cell signature, consistent with prior observation that patients with lung metastatic HCC may have higher probability of response to ICI therapy.
CONCLUSIONS
CD8 T-cell exhaustion in tumor microenvironment may predict better efficacy of ICI therapy for HCC.
PubMed: 34414122
DOI: 10.1159/000515305