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PubMed2004

Genetic and expression profiles of cerebellar liponeurocytomas.

Cerebellar liponeurocytoma, a rare, newly identified CNS neoplasm of adults, is characterized by advanced neuronal/neurocytic and focal lipomatous differentiation, low proliferative potential and a favorable clinical prognosis. Despite the different age distribution and benign biological behavior, the cerebellar liponeurocytoma shares several features with the cerebellar medulloblastoma, which may include an origin from the periventricular matrix of the fourth ventricle or the external granular layer of the cerebellum. To establish the genetic profile of cerebellar liponeurocytomas, we have formed an international consortium and collected tumor samples from 20 patients. DNA sequencing revealed TP53 missense mutations in 4 (20%) of 20 cerebellar liponeurocytomas, a frequency higher than in medulloblastomas. There was no case with PTCH, APC, or beta-catenin mutations, each of which may be present in subsets of medulloblastomas. Isochromosome 17q, a genetic hallmark of classic medulloblastomas, was not observed in any of the cases investigated by FISH analysis. cDNA array analyses were carried out on 4 cerebellar liponeurocytomas, 4 central neurocytomas, and 4 classic medulloblastomas. Cluster analysis of the cDNA expression data of 1176 genes grouped cerebellar liponeurocytomas close to central neurocytomas, but distinct from medulloblastomas. These results suggest cerebellar liponeurocytoma as a distinct tumor entity that is genetically different from medulloblastoma. Furthermore, the cDNA expression array data suggest a relationship to central neurocytomas, but the presence of TP53 mutations, which are absent in central neurocytomas, suggests that their genetic pathways are different.

Adult↗

PubMed2005

Association of amino acid substitution polymorphisms in DNA repair genes TP53, POLI, REV1 and LIG4 with lung cancer risk.

Single nucleotide polymorphisms (SNPs) were searched for in 36 genes involved in diverse DNA repair pathways, and 50 nonsynonymous (associated with amino acid changes) SNPs identified were assessed for associations with lung cancer risk by a case-control study consisting of 752 adenocarcinoma cases, 250 squamous cell carcinoma cases and 685 controls. An SNP, Arg72Pro, of the TP53 gene encoding a DNA damage response protein showed the strongest association with squamous cell carcinoma risk (OR Pro/Pro vs. Arg/Arg = 2.2), while 2 other SNPs, Phe257Ser of the REV gene encoding a translesion DNA polymerase and Ile658Val of the LIG4 gene encoding a DNA double-strand break repair protein, also showed associations (OR Ser/Ser vs. Phe/Phe = 2.0 and OR Ile/Val vs. Ile/Ile = 0.4, respectively). An SNP, Thr706Ala, in the POLI gene encoding another translesion DNA polymerase was associated with adenocarcinoma and squamous cell carcinoma risk, particularly in individuals of ages < 61 years (OR Ala/Ala + Ala/Thr vs. Thr/Thr = 1.5 and 2.4, respectively). POLI is the human counterpart of PolI, a strong candidate for the Par2 (pulmonary adenoma resistance 2) gene responsible for adenoma/adenocarcinoma susceptibility in mice. The present results suggest that these 4 SNPs function as genetic factors underlying lung cancer susceptibility by modulating activities to maintain the genome integrity of each individual.

Adenocarcinoma↗

PubMed2005

Prognostic role of E2F1 and members of the CDKN2A network in gastrointestinal stromal tumors.

PURPOSE: The aim of the current study was to examine the prognostic relevance of the CDKN2A tumor suppressor pathway in gastrointestinal stromal tumors (GIST). EXPERIMENTAL DESIGN: We determined the mRNA expression of p1(INK4A), p14(ARF), CDK4, RB1, MDM2, TP53, and E2F1 by quantitative reverse transcription-PCR in 38 cases of GISTs and correlated the findings with clinicopathologic factors, including mutation analysis of KIT and PDGFRA. RESULTS: The k-means cluster analysis yielded three prognostic subgroups of GISTs with distinct mRNA expression patterns of the CDKN2A pathway. GISTs with low mRNA expression of the CDKN2A transcripts p16(INK4A) and p14(ARF) but high mRNA expression of CDK4, RB1, MDM2, TP53, and E2F1 were associated with aggressive clinical behavior and unfavorable prognosis, whereas GISTs with a low mRNA expression of CDK4, RB1, MDM2, TP53, and E2F1 were not. GISTs with a moderate to high mRNA expression of all examined genes also seemed to be associated with unfavorable prognosis. Regarding mutation analysis, we found significant differences in the KIT/PDGFRA genotype among the three clusters. Univariate analysis revealed high expression of E2F1 to be associated with mitotic count, proliferation rate, KIT mutation, and aggressive clinical behavior. These findings on mRNA level could be confirmed by immunohistochemistry. CONCLUSION: Our findings implicate differential regulation schemes of the CDKN2A tumor suppressor pathway converging to up-regulation of E2F1 as the critical link to increased cell proliferation and adverse prognosis of GISTs.

Adult↗

PubMed1993

Lack of mutations in the P53 gene exons 5 to 8 in ataxia-telangiectasia.

Alterations of the TP53 tumor suppressor gene are present in various human malignancies and in the dominantly inherited Li-Fraumeni syndrome. Recently, a cell cycle checkpoint pathway involving p53 and GADD45 has been identified as defective in ataxia-telangiectasia. Using single strand conformation polymorphism analysis of PCR products, we looked for TP53 mutations in DNA of patients with AT. We did not find any mutation in 6 patients, suggesting that TP53 mutations are not directly involved in the cancer susceptibility observed in AT.

Ataxia Telangiectasia↗

PubMed2002

Signaling pathways in adrenocortical cancer.

Adrenocortical carcinoma is a rare tumor that carries a very poor prognosis. Despite efforts to develop new therapeutic regimens to treat this disease, surgery remains the mainstay of treatment. Laboratory studies of adrenocortical cancers have revealed a wide variety of signaling pathways that can be altered in these neoplasms. Although ACTH signaling through adenylyl cyclase and protein kinase A is important for normal adrenal cellular physiology, there is evidence to suggest that this pathway may inhibit the growth of adrenocortical tumors, and that inactivation of the ACTH receptor may promote tumor formation. Although multiple signal transduction pathways are essential for normal adrenal growth and hormone secretion, efforts to identify events required for neoplastic transformation have met with limited success. Alterations that have frequently been observed in adrenocortical carcinoma include up-regulation of the IGF-II system, as well as mutations in TP53 and RAS. Current studies aim to elucidate the mechanisms of tumor growth by studying proproliferative signaling pathways, such as those involving Akt/PKB and the mitogen-activated protein kinases (MAPKs). Although studies of single pathways have been helpful in guiding investigations, new tools to study the integration and multiplicity of signaling pathways hold the hope of improved understanding of the signaling pathway alterations in adrenocortical cancer.

Adrenal Cortex Neoplasms↗

PubMed2026

Unravelling the biological nexus of smoking and postpartum depression: a meta-analysis and functional genomics approach.

PURPOSE: Postpartum depression (PPD) is a prevalent psychological condition among birthing women. While several psycho-socio-economic and neurobiological factors influence its development, its relationship with smoking behavior and nicotine addiction remains largely inconclusive. METHODS: In this combinatorial study, we first evaluate the relationship between smoking and depressive behaviors in postpartum women using data extracted from pertinent primary epidemiological studies. Additionally, to discern the molecular and cellular mechanisms underlying this association, we identified common genetic elements and evaluated their functional attributes using in silico analyses. RESULTS: Meta-analytical assessment of systematically collected data from 38 studies indicated that smoking women are twice as likely to develop PPD, compared to their non-smoking counterparts. While geocultural attributes did not affect this relationship, timing of smoking was a significant moderator, with current and gestational smoking statuses being more strongly linked with PPD outcome, compared to the past smoking habit. Further, depression scores in smoking postpartum women were higher than those in non-smoking controls. Analysis of the common protein-encoding genes underlying the pathophysiology of nicotine addiction and PPD revealed several critical hub proteins (viz., AKT1, JUN, CTNNB1, PTEN, EGFR, ESR1, SRC, STAT3, FN1, IL1B, IL6, TNF, TP53, GAPDH, INS, MYC, and ALB) which were predicted to alter multiple pathophysiological pathways associated with transcriptional expression, intra- and intercellular signaling transduction, metabolism, and immune functions. CONCLUSION: Our results indicate that smoking is strongly associated with depressive behavior in postpartum women, although this association involve mediation of additional environmental and psychosocial elements. Moreover, network analysis of common genetic elements identified several potentially disrupted neurophysiological pathways in postpartum women with smoking and depressive behaviors which may aid in characterizing the underlying relationship between the two conditions.

Humans↗

PubMed1999

Genotype of glutathione S-transferase and other genetic configurations in myelodysplasia.

We examined polymorphisms of glutathione S-transferase (GST) genes in 159 Japanese patients with myelodysplasia and compared the incidence with that in 43 normal individuals to clarify their pathogenetic significance in myelodysplasia. In individuals with the GSTT1 null genotype, the odds ratios for disease risk were elevated to 2.65 (95%CI; 1.27-5.52) in de novo MDS, 4.62 (1.48-14.4) in therapy-related AML, and 2.94 (1.07-8.07) in AML with triliniage dysplasia. Other representative polymorphisms of GSTs had a similar incidence among patients with myelodysplasia, and those of the controls and other hematological disorders. To further investigate the genetic pathway of myelodysplasia, the association between GST genotype and karyotype or configurations of TP53 and NRAS was evaluated, but no relationship was noted. These results suggest that the GSTT1 null genotype may play a role in an increased risk of myelodysplasia unrelated to other mechanisms of myelodysplasia, such as chromosomal alterations or mutation of TP53 or NRAS.

Acute Disease↗

PubMed1998

High incidence of loss of heterozygosity at chromosome 17p13 in breast tumours from BRCA2 mutation carriers.

Breast tumours from BRCA1 and BRCA2 mutation carriers are genetically instable and display specific patterns of chromosomal aberrations, suggestive of distinct genetic pathways in tumour progression. The frequency of abnormalities affecting chromosome 17p and the TP53 gene was determined in 27 breast tumours from 26 female patients carrying the Icelandic BRCA2 founder mutation (999del5). Loss of heterozygosity (LOH) was detected in 23 of the 27 tumours (85%). The majority of tumours manifesting LOH had lost a large region on 17p, although a more restricted loss, including the TP53 locus was seen in a few tumours. Positive p53 immunostaining was observed in 18 of 26 tumours (69%). However, mutations in the TP53 gene were detected in only three tumours (11%), including a missense (codon 139) and a nonsense mutation (codon 306) in two tumours with moderate p53 expression and a frameshift deletion (codon 182) in a tumour with no detectable p53 expression. Positive p53 immunostaining, mainly weak, was observed in 16 of the 24 tumours (66%) without TP53 mutation. The high frequency of LOH at chromosome 17p13 suggests that one or more genes from this region are involved in the development of BRCA2-induced breast cancer. The frequent finding of weak overexpression of, presumably wild type p53 protein, suggests an alternative mechanism of TP53 involvement specific to these tumours.

BRCA2 Protein↗

PubMed2026

Comprehensive characterization of MET exon 14 skipping mutations in non-small cell lung cancer.

BACKGROUND: MET exon 14 skipping mutation (METΔex14) is a key driver event in non-small cell lung cancer (NSCLC) and can emerge as an acquired drug resistance mechanism to MET, EGFR or ALK inhibitors. The clinical and genomic features of METΔex14 in NSCLC require further characterization. METHODS: Our study included a total of 585 patients with METΔex14 + NSCLC, comprising 556 baseline samples, 53 samples from patients exhibiting resistance to MET inhibitors, and 16 samples from patients resistant to EGFR/ALK inhibitors. Genomic data from targeted next-generation sequencing (NGS) of tissue and/or plasma samples using GeneseeqPrime™ (a 425 pan-cancer gene panel) were analyzed. RESULTS: Overall, METΔex14 exhibited a prevalence of 1.02% (n = 585) in the screened NSCLC population, with a higher incidence in patients with a sarcomatoid histology. METΔex14 was predominantly detected at the splice donor site, though the non-coding region adjacent to the splice acceptor site contributed considerably to the complexity of METΔex14. Common concurrent alterations identified at baseline included those in TP53 (40.8%), CDK4 (16%) and EGFR (12.4%). Concurrent MET amplification and cell cycle pathway mutations were both associated with worse outcomes in patients treated with crizotinib, with significant co-occurrences observed also among these concurrent genomic variations. In addition, increased chromosomal instability and intra-tumoral heterogeneity correlated with a poorer response to crizotinib. Mechanisms of acquired resistance to MET inhibitors were primarily attributed to on-target MET D1228X/Y1230X mutations or off-target alterations within genes in the RTK/RAS/MAPK and PI3K/AKT/mTOR pathways. Intriguingly, our exploratory analysis also identified the FGFR3::TACC3 fusion as a potential resistance mechanism to savolitinib. Moreover, METΔex14 was identified in 16 patients following progression on EGFR and ALK inhibitors, highlighting the need for developing tailored therapeutic strategies to overcome resistance. CONCLUSIONS: This study provides a comprehensive characterization of METΔex14 in NSCLC, revealing its dual role as a primary driver of oncogenesis and a potential resistance mechanism to EGFR/ALK inhibitors. The identification of concurrent genetic alterations and potential resistance mechanisms enhances our molecular understanding of treatment responses. These findings highlight the need for further investigation into targeted therapies that consider the genomic complexity of METΔex14 to improve treatment efficacy and patient outcomes.

Humans↗

PubMed2001

Altered expression of TGFB receptors and mitogenic effects of TGFB in pancreatic carcinomas.

Alteration of the transforming growth factor beta (TGFB) signalling pathway is important in pancreatic carcinogenesis, as shown by the frequent inactivation of the downstream target SMAD4. We recently analysed a series of pancreatic carcinoma cell lines with respect to alterations of five SMAD genes involved in TGFB signalling, and showed that SMAD4 was structurally rearranged in 42% of these. This pathway may, however, also be affected by alterations of genes whose products regulate the activation of TGFB as well as of TGFB receptor genes. We therefore studied the expression of UPA, UPAR, IGF2R, ALK5 (TGFBR1), TGFBR2, TGFBR3, ENG, ALK1, TGFB1, TGFB2, and TGFB3 in a series of 14 pancreatic carcinoma cell lines. We also analysed ALK5 and TGFBR2 for mutations, cell surface localisation of TGFBR2 and ENG, and TGFB1 response. No mutations of ALK5 or TGFBR2 were found. However, 4 cell lines were methylated within the ALK5 promoter region. ALK5 expression was strongly reduced in 9 cases, whereas TGFBR2 expression was increased in 12 of the cell lines. The TGFB signalling associated receptors ENG and ALK1 were co-expressed in 4 of the cell lines. There was no evidence for disruption of the UPAR-IGF2R TGFB activating pathway. The response to TGFB1 was analysed in 12 cell lines, and 6 of these (50%) showed increased proliferation. The cell lines stimulated by TGFB showed frequent mutations of SMAD4, KRAS2, and TP53, as well as frequent absence of CDKN2B expression. These results suggest that the ALK5-SMAD4 part of the TGFB signalling pathway is a major target for inactivation in pancreatic carcinomas, that the expression of TGFBR2, TGFBR3, and receptors involved in TGFB activation are maintained, and that alterations of components of the TGFB signalling pathway may be accompanied by a positive effect of TGFB on cell growth.

Activin Receptors, Type I↗

PubMed1997

Cytogenetic mechanisms in the pathogenesis and progression of follicular lymphoma.

A summary of the clinically significant cytogenetic markers in follicular lymphoma is presented in Table 3. It is clear that the use of cytogenetic analysis to evaluate progression and transformation in follicular lymphoma is complicated by the variety and complexity of the chromosomal aberrations present in this disease. Cytogenetic and molecular studies have indicated that the t(14;18) translocation is the prerequisite of a multistep process in the lymphomagenesis of follicular lymphoma; it is usually followed by a long quiescent period during which the B cell population expands and additional oncogenic mutations occur leading to eventual progression and transformation to a highly malignant form. This process can be accomplished by a variety of pathways: Activation of other oncogenes by additional chromosomal rearrangements (e.g. MYC, LAZ3) Deletion and mutation of tumour suppressive genes (e.g. TP53, proposed genes on 6q) Gain of whole or parts of chromosomes, leading to increased expression of important regulating factors (e.g. MDR and T cell receptor genes on chromosome 7) More studies are required to determine which of these pathways, if any, is most important for neoplastic transformation.

Chromosome Aberrations↗

PubMed2000

Distinct clinicopathologic and genetic profiles in sporadic gastric cancer with different mutator phenotypes.

A subset of sporadic gastric cancers (GC) exhibits microsatellite instability (MSI). To define the precise role of MSI in GC, a total of 100 patients with sporadic GC were classified into three groups, i.e., high-frequency MSI (MSI-H), low-frequency MSI (MSI-L), and microsatellite stable (MSS), based on 10 microsatellite markers. Mutational analyses of TGFbetaRII, IGFIIR, BAX, MSH3, MSH6, E2F4, MSH2, MLH1, and TP53 genes, and methylation and protein expression of MLH1 and MSH2 were performed and correlated. Twenty-seven percent of GC showed MSI at least in one locus and could be further graded as MSI-H (14%) and MSI-L (13%). No clinicopathologic difference was noted between GC with MSI-L and MSS. Compared with GC with MSI-L or MSS, GC with MSI-H had a significantly higher frequency of antral location, intestinal subtype, H. pylori seropositivity, but a lower incidence of lymph node metastasis, and displayed a higher frequency of frameshift mutations of TGFbetaRII, IGFIIR, BAX, MSH3, and E2F4 genes but a lower incidence of TP53 mutations. Furthermore, hypermethylation of the MLH1 promoter was responsible for the loss of protein function in 13 of 14 MSI-H tumors. It was concluded that a specific phenotype and a distinct profile of genetic alterations exist in MSI-H GC. We speculate that epigenetic inactivation of MLH1 by methylation plays a crucial role in initiating such a pathway of carcinogenesis. In contrast, GCs with MSS and MSI-L exhibit clinicopathologic features that are distinct from MSI-H tumors and have a higher frequency of TP53 mutations, suggesting that they may evolve through an entirely different pathway.

Adaptor Proteins, Signal Transducing↗

PubMed2023

Discussion on the mechanism of Lingguizhugan Decoction in treating hypertension based on network pharmacology and molecular simulation technology.

To explore the mechanism of Lingguizhugan Decoction in treating hypertension based on network pharmacology and molecular simulation. The active ingredients and potential targets were screened by the Systematic Pharmacological Analysis Platform of Traditional Chinese Medicine (TCMSP). Hypertension-related targets were obtained from OMIM and GeneCards databases. Common targets between drug and hypertension were screened in the Venny platform. A protein-protein interaction (PPI) network was constructed in the STRING database using intersection targets. Key targets in PPI network were analyzed by Cytoscape. R language program was used for Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Finally, the binding abilities of the main active ingredients to critical targets were verified by molecular simulation. Naringenin, quercetin, kaempferol, and β-sitosterol in Lingguizhugan Decoction, and potential targets such as STAT3, AKT1, TNF, IL6, JUN, PTGS2, MMP9, CASP3, TP53, and MAPK3, were screened out. KEGG Enrichment analysis revealed that the common targets of Lingguizhugan Decoction and hypertension are mainly involved in the lipid and atherosclerosis signaling pathway, AGE-RAGE signaling pathway in diabetic complications, fluid shear stress and atherosclerosis, and IL17 signaling pathway. The molecular simulation results showed that naringenin-MAPK3, quercetin-MMP9, quercetin-PTGS2, and quercetin-TP53 were the top four in the docking scores. Naringenin-MAPK3 and quercetin-MMP9 were stable, with binding free energies of -27.97 ± 1.41 kcal/mol and -21.15 ± 3.17 kcal/mol, respectively. The possible mechanism of Lingguizhugan Decoction in treating hypertension is characterized of multi-component, multi-target, and multi-pathway.Communicated by Ramaswamy H. Sarma.

Network Pharmacology↗

PubMed2025

Integrated data mining and network pharmacology to explore the prescription patterns from a senior TCM oncologist's clinical practice in treating chemotherapy-induced hand-foot syndrome.

Hand-foot syndrome (HFS) is a common and refractory adverse effect of chemotherapy lacking specific therapeutic strategies currently. Traditional Chinese medicine (TCM) has shown empirical efficacy in clinical HFS management. This study integrated data mining and network pharmacology to systematically elucidate the medication principles and molecular mechanisms underlying Professor Gang Xie's prescriptions for HFS. All medical records from Professor Xie's specialist clinic (January 2020 to March 2025) were retrospectively collected and standardized in Excel. Prescriptions were analyzed through frequency statistics, association and clustering. Active ingredients of core herb pairs and their disease-related targets were identified using TCMSP, HERB, GeneCards, PharmGKB and GEO databases. Protein-protein interaction (PPI) networks, gene ontology (GO), and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses were performed. Molecular docking validated interactions between key bioactive compounds and targets. This study involved 217 prescriptions containing 150 herbs. Core herb combinations comprised Radix Astragali (Huangqi), Poria (Fuling), and Radix Pseudostellariae (Taizishen), predominantly classified as spleen-tonifying agents with warm properties, targeting lung, spleen, and stomach meridians. Network analysis identified 67 bioactive compounds and 899 disease targets. Quercetin, kaempferol, acacetin and luteolin were identified the key ingredients. The core targets (TP53, STAT3, PIK3CA, HSP90AA1, AKT1, CTNNB1, PI3KR1, MAPK1) were enriched in MAPK and PI3K-Akt signaling pathways. Molecular docking confirmed strong binding affinity between key compounds and targets. Professor Xie's therapeutic strategy for HFS emphasizes "spleen fortification, phlegm elimination, and stasis resolution." The core herb combination likely exerts anti-HFS effects via modulation of MAPK and PI3K-Akt pathways, providing a pharmacological basis for TCM-driven HFS management.

Network Pharmacology↗

PubMed1998

A genetic perspective of male germ cell tumors.

Adult human male germ cell tumors (GCTs) arise by transformation of germ cells (GCs). The transformed GCs exhibit pluripotentiality to differentiate into embryonic, extra-embryonic, and somatic tissue types, and are highly sensitive to cisplatin-based chemotherapy. Recent investigations into the genetics of GCTs have advanced methods of diagnosis and provided leads to the understanding of molecular basis of transformation, differentiation, and sensitivity/resistance. Cytogenetic and molecular cytogenetic studies have identified multiplication of 12p, manifested in i(12p) or tandem duplication of 12p, as a unique change in GCTs which serves as a diagnostic marker. Ectopic over-expression of cyclin D2, a gene mapped to 12p, as early as in carcinoma in situ identifies a candidate gene in GC transformation. Genetic alterations identified in the tumor suppressor genes deleted in colorectal cancer, retinoblastoma 1 and non-metastatic protein 23 (NME) in GCT suggest that their inactivation play a key role in transformation or differentiation. A number of regions of chromosomal deletion have been identified including those previously known to be deleted in various tumor types and novel candidate tumor suppressor gene sites such as 12q13, 12q22, and 5p15.1-15.2. Identification and characterization of the genes in these sites will provide important clues in understanding the biology of GCT. The molecular studies have also enumerated several possible differentiation controls such as switching of KIT and mast cell growth factor gene expression in a lineage-associated manner, and loss of certain types of genes such as NME in teratomas that may act in a dominant negative fashion in differentiation. The exquisite sensitivity of these tumors to chemotherapy is reflected in their over-expression of wild-type p53 protein and lack of TP53 mutations. These data indicate that multiple genetic events play a role in distinct pathways in the development of GCT, and further elucidation of the underlying genetic and biochemical mechanisms is central to unraveling biology and improving treatment of GCT.

Chromosome Aberrations↗

PubMed1997

Molecular alterations of the RB1, TP53, and MDM2 genes in primary and xenografted human osteosarcomas.

We report the status of the RB1, TP53, and MDM2 genes in human osteosarcomas and cell lines established from surgical specimens and transplanted into athymic naked mice. By using reverse transcriptase-polymerase chain reaction (RT-PCR) as a prescreening technique and posterior sequencing, we observe new mutations in the RB1 gene, notably a duplication in tandem of exons 3 through 6. TP53 mutations appear in codons most frequently mutated in osteosarcomas. We have not seen MDM2 gene amplification in any reported case. These molecular alterations appear in different osteosarcomas not simultaneously present in the same tumor sample. A link has been described between these three genes in the pathways that control the cell cycle and the tumoral progression, but their functions are probably independent in the development of osteosarcomas. TP53 mutations appear in adult patients, whereas RB1 alterations occur mostly in younger patients.

Adolescent↗

PubMed2003

P53 and radiation responses.

Cells have evolved elaborate mechanisms (checkpoints) to monitor genomic integrity in order to ensure the high-fidelity transmission of genetic information. Cells harboring defects in checkpoint pathways respond to DNA damage improperly, which in turn may enhance the rate of cancer development. Ionizing radiation (IR) primarily leads to double-strand DNA breaks (DSBs), which activate DNA damage checkpoints to initiate signals ultimately leading to a binary decision between cell death and cell survival. TP53 has been recognized as an important checkpoint protein, functioning mainly through transcriptional control of target genes that influence multiple response pathways and leading to the diversity of responses to IR in mammalian cells. We review how the tumor suppressor P53 is involved in the complex response to IR to enforce the cell's fate to live by inducing the growth arrest coupled to DNA damage repair or to die by inducing irreversible growth arrest or apoptosis. Moreover, recent insights have emerged in our understanding of how P53 modulates radiosensitivity in tissues following IR as well as its role in sensitizing cells to chemo- and radiotherapy. The P53 pathway remains an attractive target for exploitation in the war on cancer.

DNA Damage↗

PubMed2025

Targeting CyclinD1-CDK6 to Mitigate Senescence-Driven Inflammation and Age-Associated Functional Decline.

Cellular senescence contributes to aging and age-related diseases by driving chronic inflammation through the Senescence Associated Secretory Phenotype (SASP) and interferon-stimulated genes (ISGs). Cyclin D1 (CCND1), a key cell cycle regulator, is paradoxically upregulated in these non-proliferating cells. We show that CCND1 and its kinase partner CDK6 drive SASP and ISG expression in senescent cells by promoting DNA damage accumulation. This leads to the formation of cytoplasmic chromatin fragments (CCFs) that activate pro-inflammatory CGAS-STING signaling. The tumor suppressor p53 (TP53) and its target p21 (CDKN2A) antagonize this CCND1-CDK6-dependent DNA damage accumulation pathway to suppress the SASP. In aged mouse livers, senescent hepatocytes show increased Ccnd1 expression. Hepatocyte-specific Ccnd1 knockout or treatment with the Cdk4/6 inhibitor Palbociclib reduces DNA damage and ISGs in aged mouse liver. Notably, Palbociclib also suppresses frailty and improves physical performance of aged mice. These findings reveal a novel role for CCND1/CDK6 in regulating DNA damage and inflammation in senescence and aging, highlighting it as a promising therapeutic target.

Journal Article↗