A Balancing Act: p53 Activity from Tumor Suppression to Pathology and Therapeutic Implications

Author(s):  
Mengxiong Wang ◽  
Laura D. Attardi

TP53, encoding the p53 transcription factor, is the most frequently mutated tumor suppressor gene across all human cancer types. While p53 has long been appreciated to induce antiproliferative cell cycle arrest, apoptosis, and senescence programs in response to diverse stress signals, various studies in recent years have revealed additional important functions for p53 that likely also contribute to tumor suppression, including roles in regulating tumor metabolism, ferroptosis, signaling in the tumor microenvironment, and stem cell self-renewal/differentiation. Not only does p53 loss or mutation cause cancer, but hyperactive p53 also drives various pathologies, including developmental phenotypes, premature aging, neurodegeneration, and side effects of cancer therapies. These findings underscore the importance of balanced p53 activity and influence our thinking of how to best develop cancer therapies based on modulating the p53 pathway. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


Author(s):  
Sihan Wu ◽  
Vineet Bafna ◽  
Howard Y. Chang ◽  
Paul S. Mischel

Human genes are arranged on 23 pairs of chromosomes, but in cancer, tumor-promoting genes and regulatory elements can free themselves from chromosomes and relocate to circular, extrachromosomal pieces of DNA (ecDNA). ecDNA, because of its nonchromosomal inheritance, drives high-copy-number oncogene amplification and enables tumors to evolve their genomes rapidly. Furthermore, the circular ecDNA architecture fundamentally alters gene regulation and transcription, and the higher-order organization of ecDNA contributes to tumor pathogenesis. Consequently, patients whose cancers harbor ecDNA have significantly shorter survival. Although ecDNA was first observed more than 50 years ago, its critical importance has only recently come to light. In this review, we discuss the current state of understanding of how ecDNAs form and function as well as how they contribute to drug resistance and accelerated cancer evolution. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.



Author(s):  
Alicia M. McConnell ◽  
Haley R. Noonan ◽  
Leonard I. Zon

Zebrafish are rapidly becoming a leading model organism for cancer research. The genetic pathways driving cancer are highly conserved between zebrafish and humans, and the ability to easily manipulate the zebrafish genome to rapidly generate transgenic animals makes zebrafish an excellent model organism. Transgenic zebrafish containing complex, patient-relevant genotypes have been used to model many cancer types. Here we present a comprehensive review of transgenic zebrafish cancer models as a resource to the field and highlight important areas of cancer biology that have yet to be studied in the fish. The ability to image cancer cells and niche biology in an endogenous tumor make zebrafish an indispensable model organism in which we can further understand the mechanisms that drive tumorigenesis and screen for potential new cancer therapies. Expected final online publication date for the Annual Review of Cancer Biology, Volume 5 is March 4, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.



2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Natalie Y.L. Ngoi ◽  
Guang Peng ◽  
Timothy A. Yap

Innate immunity and the DNA damage response (DDR) pathway are inextricably linked. Within the DDR, ataxia telangiectasia and Rad3-related (ATR) is a key kinase responsible for sensing replication stress and facilitating DNA repair through checkpoint activation, cell cycle arrest, and promotion of fork recovery. Recent studies have shed light on the immunomodulatory role of the ATR-CHK1 pathway in the tumor microenvironment and the specific effects of ATR inhibition in stimulating an innate immune response. With several potent and selective ATR inhibitors in developmental pipelines, the combination of dual ATR and PD-(L)1 blockade has attracted increasing interest in cancer therapy. In this review, we summarize the clinical and preclinical data supporting the combined inhibition of ATR and PD-(L)1, discuss the potential challenges surrounding this approach, and highlight biomarkers relevant for selected patients who are most likely to benefit from the blockade of these two checkpoints. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.



Author(s):  
Thomas B. Alexander ◽  
Charles G. Mullighan

Childhood hematological malignancies (HM) exhibit profound genetic and biological heterogeneity. Many sporadic and familial HM have a heritable predisposition. Genomic sequencing has revised the taxonomy of lymphoid and myeloid leukemias, indicating the importance of accurate molecular diagnosis in disease management. Notable examples include the identification of gene expression–based subtypes of acute lymphoblastic leukemia (ALL), identification of diverse rearrangements of NUP98 in high-risk acute myeloid leukemia (AML), characterization of the interplay of cell-of-origin and genomic alterations in lineage-ambiguous leukemias, and the prognostic importance of DNA methylation in juvenile myelomonocytic leukemias. These insights provide therapeutic opportunities, including kinase inhibition in Ph-like ALL, menin inhibition in KMT2A-rearranged AML, histone deacetylase inhibition in MEF2D-rearranged ALL, and FLT3 inhibition in T-lineage and myeloid leukemias. We provide an overview of the molecular foundation and classification of childhood leukemias, focusing on recent scientific advances, and discuss potential therapeutic implications. Expected final online publication date for the Annual Review of Cancer Biology, Volume 5 is March 4, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.



Author(s):  
Giselle M. Boukhaled ◽  
Shane Harding ◽  
David G. Brooks

The immune system is tasked with identifying malignant cells to eliminate or prevent cancer spread. This involves a complex orchestration of many immune cell types that together recognize different aspects of tumor transformation and growth. In response, tumors have developed mechanisms to circumvent immune attack. Type I interferons (IFN-Is) are a class of proinflammatory cytokines produced in response to viruses and other environmental stressors. IFN-Is are also emerging as essential drivers of antitumor immunity, potently stimulating the ability of immune cells to eliminate tumor cells. However, a more complicated role for IFN-Is has arisen, as prolonged stimulation can promote feedback inhibitory mechanisms that contribute to immune exhaustion and other deleterious effects that directly or indirectly permit cancer cells to escape immune clearance. We review the fundamental and opposing functions of IFN-Is that modulate tumor growth and impact immune function and ultimately how these functions can be harnessed for the design of new cancer therapies. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 16 is January 25, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.



Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6232
Author(s):  
Pey-Tsyr Chiou ◽  
Stephen Ohms ◽  
Philip G. Board ◽  
Jane E. Dahlstrom ◽  
Danny Rangasamy ◽  
...  

Although many breast cancer therapies show initial success in the treatment of the primary tumour, they often fail to eliminate a sub-population of cells known as cancer stem cells (CSCs). These cells are recognised for their self-renewal properties and for their capacity for differentiation often leading to chemo/radio-resistance. The antiviral drug Efavirenz has been shown to be effective in eliminating triple-negative breast cancer cells, and here we examine its effect on breast CSCs. The effects of Efavirenz on CSCs for several breast cancer cell lines were investigated by examining cellular changes upon drug treatment, including CSC numbers, morphology, RNA/microRNA expression and levels of epithelial/mesenchymal CSC subtypes. Efavirenz treatment resulted in a decrease in the size and number of tumorspheres and a reduction in epithelial-type CSC levels, but an increase in mesenchymal-type CSCs. Efavirenz caused upregulation of several CSC-related genes as well as miR-21, a CSC marker and miR-182, a CSC suppressor gene. We conclude that Efavirenz alters the phenotype and expression of key genes in breast CSCs, which has important potential therapeutic implications.



2020 ◽  
Vol 15 (6) ◽  
pp. 482-491 ◽  
Author(s):  
Milena Kostadinova ◽  
Milena Mourdjeva

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.



2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chiharu Uchida

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.



2021 ◽  
Vol 22 (16) ◽  
pp. 8372
Author(s):  
Ana María Zárate ◽  
Christian Espinosa-Bustos ◽  
Simón Guerrero ◽  
Angélica Fierro ◽  
Felipe Oyarzún-Ampuero ◽  
...  

The Smoothened (SMO) receptor is the most druggable target in the Hedgehog (HH) pathway for anticancer compounds. However, SMO antagonists such as vismodegib rapidly develop drug resistance. In this study, new SMO antagonists having the versatile purine ring as a scaffold were designed, synthesised, and biologically tested to provide an insight to their mechanism of action. Compound 4s was the most active and the best inhibitor of cell growth and selectively cytotoxic to cancer cells. 4s induced cell cycle arrest, apoptosis, a reduction in colony formation and downregulation of PTCH and GLI1 expression. BODIPY-cyclopamine displacement assays confirmed 4s is a SMO antagonist. In vivo, 4s strongly inhibited tumour relapse and metastasis of melanoma cells in mice. In vitro, 4s was more efficient than vismodegib to induce apoptosis in human cancer cells and that might be attributed to its dual ability to function as a SMO antagonist and apoptosis inducer.



Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 789
Author(s):  
Li-Ming Liu ◽  
Qiang Tang ◽  
Xin Hu ◽  
Jing-Jing Zhao ◽  
Yuan Zhang ◽  
...  

The protein p53 is one of the most important tumor suppressors, responding to a variety of stress signals. Mutations in p53 occur in about half of human cancer cases, and dysregulation of the p53 function by epigenetic modifiers and modifications is prevalent in a large proportion of the remainder. PRMT1 is the main enzyme responsible for the generation of asymmetric-dimethylarginine, whose upregulation or aberrant splicing has been observed in many types of malignancies. Here, we demonstrate that p53 function is regulated by PRMT1 in breast cancer cells. PRMT1 knockdown activated the p53 signal pathway and induced cell growth-arrest and senescence. PRMT1 could directly bind to p53 and inhibit the transcriptional activity of p53 in an enzymatically dependent manner, resulting in a decrease in the expression levels of several key downstream targets of the p53 pathway. We were able to detect p53 asymmetric-dimethylarginine signals in breast cancer cells and breast cancer tissues from patients, and the signals could be significantly weakened by silencing of PRMT1 with shRNA, or inhibiting PRMT1 activity with a specific inhibitor. Furthermore, PRMT1 inhibitors significantly impeded cell growth and promoted cellular senescence in breast cancer cells and primary tumor cells. These results indicate an important role of PRMT1 in the regulation of p53 function in breast tumorigenesis.



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