scholarly journals MDM2/X Inhibitors as Radiosensitizers for Glioblastoma Targeted Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Xanthene Miles ◽  
Charlot Vandevoorde ◽  
Alistair Hunter ◽  
Julie Bolcaen
Keyword(s):  
Dna Damage ◽  
Therapeutic Interventions ◽  
Cellular Damage ◽  
Current Status ◽  
Cancer Therapies ◽  
Downstream Signaling ◽  
Cycle Arrest ◽  
Radiation Induced ◽  
P53 Activation

Inhibition of the MDM2/X-p53 interaction is recognized as a potential anti-cancer strategy, including the treatment of glioblastoma (GB). In response to cellular stressors, such as DNA damage, the tumor suppression protein p53 is activated and responds by mediating cellular damage through DNA repair, cell cycle arrest and apoptosis. Hence, p53 activation plays a central role in cell survival and the effectiveness of cancer therapies. Alterations and reduced activity of p53 occur in 25-30% of primary GB tumors, but this number increases drastically to 60-70% in secondary GB. As a result, reactivating p53 is suggested as a treatment strategy, either by using targeted molecules to convert the mutant p53 back to its wild type form or by using MDM2 and MDMX (also known as MDM4) inhibitors. MDM2 down regulates p53 activity via ubiquitin-dependent degradation and is amplified or overexpressed in 14% of GB cases. Thus, suppression of MDM2 offers an opportunity for urgently needed new therapeutic interventions for GB. Numerous small molecule MDM2 inhibitors are currently undergoing clinical evaluation, either as monotherapy or in combination with chemotherapy and/or other targeted agents. In addition, considering the major role of both p53 and MDM2 in the downstream signaling response to radiation-induced DNA damage, the combination of MDM2 inhibitors with radiation may offer a valuable therapeutic radiosensitizing approach for GB therapy. This review covers the role of MDM2/X in cancer and more specifically in GB, followed by the rationale for the potential radiosensitizing effect of MDM2 inhibition. Finally, the current status of MDM2/X inhibition and p53 activation for the treatment of GB is given.

Potential of Mesenchymal Stem Cells in Anti-Cancer Therapies

2020 ◽  
Vol 15 (6) ◽  
pp. 482-491 ◽  
Author(s):  
Milena Kostadinova ◽  
Milena Mourdjeva
Keyword(s):  
Cancer Cells ◽  
Small Population ◽  
Tumor Formation ◽  
Bioactive Molecules ◽  
Cancer Therapies ◽  
New Methods ◽  
Cycle Arrest ◽  
Anti Cancer ◽  
Blocking Mechanisms

Mesenchymal stem/stromal cells (MSCs) are localized throughout the adult body as a small population in the stroma of the tissue concerned. In injury, tissue damage, or tumor formation, they are activated and leave their niche to migrate to the site of injury, where they release a plethora of growth factors, cytokines, and other bioactive molecules. With the accumulation of data about the interaction between MSCs and tumor cells, the dualistic role of MSCs remains unclear. However, a large number of studies have demonstrated the natural anti-tumor properties inherent in MSCs, so this is the basis for intensive research for new methods using MSCs as a tool to suppress cancer cell development. This review focuses specifically on advanced approaches in modifying MSCs to become a powerful, precision- targeted tool for killing cancer cells, but not normal healthy cells. Suppression of tumor growth by MSCs can be accomplished by inducing apoptosis or cell cycle arrest, suppressing tumor angiogenesis, or blocking mechanisms mediating metastasis. In addition, the chemosensitivity of cancer cells may be increased so that the dose of the chemotherapeutic agent used could be significantly reduced.

scholarly journals Roles of pRB in the Regulation of Nucleosome and Chromatin Structures

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chiharu Uchida
Keyword(s):  
Target Genes ◽  
Chromosome Instability ◽  
Cancer Therapies ◽  
Induce Cell Cycle Arrest ◽  
Cellular Events ◽  
Cycle Arrest ◽  
Histone Modifiers ◽  
Physical Interactions ◽  
Functional Inactivation

Retinoblastoma protein (pRB) interacts with E2F and other protein factors to play a pivotal role in regulating the expression of target genes that induce cell cycle arrest, apoptosis, and differentiation. pRB controls the local promoter activity and has the ability to change the structure of nucleosomes and/or chromosomes via histone modification, epigenetic changes, chromatin remodeling, and chromosome organization. Functional inactivation of pRB perturbs these cellular events and causes dysregulated cell growth and chromosome instability, which are hallmarks of cancer cells. The role of pRB in regulation of nucleosome/chromatin structures has been shown to link to tumor suppression. This review focuses on the ability of pRB to control nucleosome/chromatin structures via physical interactions with histone modifiers and chromatin factors and describes cancer therapies based on targeting these protein factors.

scholarly journals PARP Power: A Structural Perspective on PARP1, PARP2, and PARP3 in DNA Damage Repair and Nucleosome Remodelling

2021 ◽  
Vol 22 (10) ◽  
pp. 5112
Author(s):  
Lotte van Beek ◽  
Éilís McClay ◽  
Saleha Patel ◽  
Marianne Schimpl ◽  
Laura Spagnolo ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Binding ◽  
Parp Inhibitors ◽  
Covalent Modification ◽  
Activation Mechanism ◽  
Cancer Therapies ◽  
Damage Repair ◽  
Complementary Role ◽  
Functional Understanding

Poly (ADP-ribose) polymerases (PARP) 1-3 are well-known multi-domain enzymes, catalysing the covalent modification of proteins, DNA, and themselves. They attach mono- or poly-ADP-ribose to targets using NAD+ as a substrate. Poly-ADP-ribosylation (PARylation) is central to the important functions of PARP enzymes in the DNA damage response and nucleosome remodelling. Activation of PARP happens through DNA binding via zinc fingers and/or the WGR domain. Modulation of their activity using PARP inhibitors occupying the NAD+ binding site has proven successful in cancer therapies. For decades, studies set out to elucidate their full-length molecular structure and activation mechanism. In the last five years, significant advances have progressed the structural and functional understanding of PARP1-3, such as understanding allosteric activation via inter-domain contacts, how PARP senses damaged DNA in the crowded nucleus, and the complementary role of histone PARylation factor 1 in modulating the active site of PARP. Here, we review these advances together with the versatility of PARP domains involved in DNA binding, the targets and shape of PARylation and the role of PARPs in nucleosome remodelling.

The essential role of p21 in radiation-induced cell cycle arrest of vascular smooth muscle cell

2004 ◽  
Vol 37 (4) ◽  
pp. 871-880 ◽  
Author(s):  
Hyo-Soo Kim ◽  
Hyun-Jai Cho ◽  
Hyun-Ju Cho ◽  
Sun-Jung Park ◽  
Kyung-Woo Park ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Cell Cycle Arrest ◽  
Muscle Cell ◽  
Essential Role ◽  
Cycle Arrest ◽  
Radiation Induced

Re-Examination of the Exacerbating Effect of Inflammasome Components during Radiation Injury

2021 ◽  
Author(s):  
W. June Brickey ◽  
Michael A. Thompson ◽  
Zhecheng Sheng ◽  
Zhiguo Li ◽  
Kouros Owzar ◽  
...  
Keyword(s):  
Cellular Response ◽  
Radiation Injury ◽  
Therapeutic Benefit ◽  
Acute Radiation ◽  
Cellular Damage ◽  
Inflammatory Factors ◽  
Experimental Conditions ◽  
Acute Radiation Injury ◽  
Radiation Induced

Radiation can be applied for therapeutic benefit against cancer or may result in devastating harm due to accidental or intentional release of nuclear energy. In all cases, radiation exposure causes molecular and cellular damage, resulting in the production of inflammatory factors and danger signals. Several classes of innate immune receptors sense the released damage associated molecules and activate cellular response pathways, including the induction of inflammasome signaling that impacts IL-1β/IL-18 maturation and cell death. A previous report indicated inflammasomes aggravate acute radiation syndrome. In contrast, here we find that inflammasome components do not exacerbate gamma-radiation-induced injury by examining heterozygous and gene-deletion littermate controls in addition to wild-type mice. Absence of some inflammasome genes, such as caspase-1/11 and Nlrp3, enhance susceptibility of treated mice to acute radiation injury, indicating importance of the inflammasome pathway in radioprotection. Surprisingly, we discover that the survival outcome may be sex-dependent as more inflammasome-deficient male mice are susceptible to radiation-induced injury. We discuss parameters that may influence the role of inflammasomes as radioprotective or radioexacerbating factors in recovery from radiation injury including the use of littermate controls, the sex of the animals, differences in microbiota within the colonies and other experimental conditions. Under the conditions tested, inflammasome components do not exacerbate radiation injury, but rather provide protective benefit.

scholarly journals Molecular and Immune Biomarkers for Cutaneous Melanoma: Current Status and Future Prospects

Cancers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3456 ◽  
Author(s):  
Lorenzo Pilla ◽  
Andrea Alberti ◽  
Pierluigi Di Mauro ◽  
Maria Gemelli ◽  
Viola Cogliati ◽  
...  
Keyword(s):  
Molecular Basis ◽  
Predictive Biomarkers ◽  
Therapeutic Interventions ◽  
Current Status ◽  
Immune Biomarkers ◽  
Clinical Responses ◽  
Melanoma Patients ◽  
Immunological Assays ◽  
The Relationship

Advances in the genomic, molecular and immunological make-up of melanoma allowed the development of novel targeted therapy and of immunotherapy, leading to changes in the paradigm of therapeutic interventions and improvement of patients’ overall survival. Nevertheless, the mechanisms regulating either the responsiveness or the resistance of melanoma patients to therapies are still mostly unknown. The development of either the combinations or of the sequential treatment of different agents has been investigated but without a strongly molecularly motivated rationale. The need for robust biomarkers to predict patients’ responsiveness to defined therapies and for their stratification is still unmet. Progress in immunological assays and genomic techniques as long as improvement in designing and performing studies monitoring the expression of these markers along with the evolution of the disease allowed to identify candidate biomarkers. However, none of them achieved a definitive role in predicting patients’ clinical outcomes. Along this line, the cross-talk of melanoma cells with tumor microenvironment plays an important role in the evolution of the disease and needs to be considered in light of the role of predictive biomarkers. The overview of the relationship between the molecular basis of melanoma and targeted therapies is provided in this review, highlighting the benefit for clinical responses and the limitations. Moreover, the role of different candidate biomarkers is described together with the technical approaches for their identification. The provided evidence shows that progress has been achieved in understanding the molecular basis of melanoma and in designing advanced therapeutic strategies. Nevertheless, the molecular determinants of melanoma and their role as biomarkers predicting patients’ responsiveness to therapies warrant further investigation with the vision of developing more effective precision medicine.

scholarly journals Role of inhibitory CDC2 phosphorylation in radiation-induced G2 arrest in human cells.

1996 ◽  
Vol 134 (4) ◽  
pp. 963-970 ◽  
Author(s):  
P Jin ◽  
Y Gu ◽  
D O Morgan
Keyword(s):  
Dna Damage ◽  
Chromatin Condensation ◽  
S Phase ◽  
Human Cells ◽  
G2 Arrest ◽  
Hela Cell Lines ◽  
Radiation Induced ◽  
G2 Delay ◽  
In Cells

The activity of the mitosis-promoting kinase CDC2-cyclin B is normally suppressed in S phase and G2 by inhibitory phosphorylation at Thr14 and Tyr15. This work explores the possibility that these phosphorylations are responsible for the G2 arrest that occurs in human cells after DNA damage. HeLa cell lines were established in which CDC2AF, a mutant that cannot be phosphorylated at Thr14 and Tyr15, was expressed from a tetracycline-repressible promoter. Expression of CDC2AF did not induce mitotic events in cells arrested at the beginning of S phase with DNA synthesis inhibitors, but induced low levels of premature chromatin condensation in cells progressing through S phase and G2. Expression of CDC2AF greatly reduced the G2 delay that resulted when cells were X-irradiated in S phase. However, a significant G2 delay was still observed and was accompanied by high CDC2-associated kinase activity. Expression of wild-type CDC2, or the related kinase CDK2AF, had no effect on the radiation-induced delay. Thus, inhibitory phosphorylation of CDC2, as well as additional undefined mechanisms, delay mitosis after DNA damage.

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