Aging aggravates aortic aneurysm and dissection via miR-1204-MYLK signaling axis in mice.

The mechanism by which aging induces aortic aneurysm and dissection (AAD) remains unclear. A total of 430 participants were recruited for the screening of differentially expressed plasma microRNAs (miRNAs). We found that miR-1204 is significantly increased in both the plasma and aorta of elder patients with AAD and is positively correlated with age. Cell senescence induces the expression of miR-1204 through p53 interaction with plasmacytoma variant translocation 1, and miR-1204 induces vascular smooth muscle cell (VSMC) senescence to form a positive feedback loop. Furthermore, miR-1204 aggravates angiotensin II-induced AAD formation, and inhibition of miR-1204 attenuates ß-aminopropionitrile monofumarate-induced AAD development in mice. Mechanistically, miR-1204 directly targets myosin light chain kinase (MYLK), leading to the acquisition of a senescence-associated secretory phenotype (SASP) by VSMCs and loss of their contractile phenotype. MYLK overexpression reverses miR-1204-induced VSMC senescence, SASP and contractile phenotypic changes, and the decrease of transforming growth factor-ß signaling pathway. Our findings suggest that aging aggravates AAD via the miR-1204-MYLK signaling axis.

Impact of khat (Catha edulis) and oral contraceptive use on telomerase levels and tumor suppressor genes p53 and p21 in normal subjects and breast cancer patients.

This study aimed to evaluate the effects of oral contraceptive (OC) use, khat chewing, and their combined effect on telomerase level and tumor suppressor genes, p53 and p21 in breast cancer (BC) patients and normal volunteers. 140 Yemeni women aged 25-40 years old enrolled, 60 newly diagnosed pretreated BC patients, and 80 control subjects. Venous blood (5 ml) was collected and the results showed BC patients to have significantly raised levels of telomerase, p53, and p21 compared to the control group. The use of OCs significantly raised telomerase in control group with no effect in BC patients; whereas p53 and p21 were significantly increased in BC patients. On the other hand, khat chewing significantly increased p53 in controls and BC patients, whereas p21 was significantly raised in BC patients. The combined use of OCs and khat chewing significantly increased telomerase and p53 in control group, and significantly increased p53 and p21 in BC patients. Telomerase was shown to be a risk factor (OR 4.4) for BC, and the use of OCs was a high-risk factor for increasing telomerase (OR 27.8) in normal subjects. In contrast, khat chewing was shown to be protective (OR 0.142), and the combined use of OCs and khat chewing decreased the risk factor of telomerase from OR 27.8 to 2.1.

[Relationship between GTSE1 and Cell Cycle and Potential Regulatory Mechanisms 
in Lung Cancer Cells].

The regulation of the cell cycle is essential for maintaining normal cellular function, especially in the development of diseases such as lung cancer. The cell cycle consists of four major phases (G1, S, G2 and M phases), which are characterized by a series of precise molecular events to ensure proper cell proliferation and division. In lung cancer cells, cell cycle dysregulation can lead to disordered proliferation and increased invasiveness of cancer cells. G2 and S-phase expressed 1 (GTSE1) is a regulatory protein found in the cytoplasm of the cell, which plays a key role in the cell cycle distribution of a wide range of cancer cells and is involved in life processes such as cell proliferation and apoptosis. GTSE1 affects cell cycle progression by interacting with cyclin-dependent kinase inhibitor 1A (p21) and maintaining the stability of p21, which in turn inhibits the activity of cyclin-dependent kinase 1/2 (CDK1/2). In addition, GTSE1 is also involved in the regulation of tumor protein 53 (p53) signaling pathway. With the assistance of mouse double minute 2 homolog (MDM2), GTSE1 is able to transport p53 from the nucleus to the cytoplasm and promote its ubiquitination and degradation, thus affecting cell cycle and cell death-related signaling pathways. This paper reviews the expression of GTSE1 in lung cancer cells and its effects on lung cancer, as well as its potential mechanisms involved in cell cycle regulation.
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p16, p53 and EGFR expression in head and neck squamous cell carcinoma and their correlation with clinicopathological parameters.

INTRODUCTION: Oral squamous cell carcinoma is a major cause of death throughout the developed world. Human papillomavirus (HPV) type 16 has also been suggested to play a role in etiology of head and neck squamous cell carcinoma (HNSCC). p16 expression is now being used as a surrogate marker of HPV infection in squamous cell carcinoma. Dysfunction in the p53 tumor suppressor gene is implicated in many cancers, including head and neck cancer. Overexpression or mutation of EGFR is found in 80%-100% of the patients with HNSCC, and is associated with poor prognosis and decreased survival. MATERIALS AND METHODS: In this cross-sectional observation study, total of 100 cases of HNSCC were taken. p16, p53, and EGFR expression was determined by immunohistochemical staining and correlated with clinicopathological parameters. p16 expression was also correlated with expression of p53 and EGFR. The obtained results were analyzed and evaluated using Chi-square test, value of P < 0.05 was taken significant. RESULTS: p16, p53, and EGFR were positive in 60%, 44%, and 58% cases, respectively. A statistically significant association was observed between p16 with age, site of the tumor, abnormal sexual habits and lymph node involvement. Significant expression also seen between p53 with age and abnormal sexual habits and immunohistochemical expression of p16 with p53 and EGFR. CONCLUSION: Immunohistochemical expression of p16 can be used as a surrogate marker of HPV. Study of p16, p53, and EGFR expression may provide clinicians with more exact information in order to evaluate tumor aggressiveness and treatment modalities.

Case report: TP53 c.848G>A germline mutation as a possible screening target at initial diagnosis for acute lymphoblastic leukemia.

BACKGROUD: Li-Fraumeni syndrome is a hereditary tumor syndrome characterized by an elevated risk of malignancy, particularly acute lymphoblastic leukemia (ALL), which can be caused by the heterozygous germline mutation. TP53 gene germline mutation is considered a potential risk factor and crucial prognostic parameter for acute leukemia development and diagnosis, but rarely occurs in adults, and its specific pathogenic significance in acute leukemia is unclear. CASE PRESENTATION: We describes a case of a 45-year-old woman diagnosed with ALL. Whole-exome sequencing approach identified one of the TP53 germline mutations from her bone marrow sample with possible pathogenic significance, c.848G>A (p.Arg283His) heterozygous missense mutation located on exon 8, which was further verified in her hair, oral mucous and nail samples. Family pedigree screening revealed that the same TP53 genetic variant was present in the patient's father and non-donor son, whereas not in the donor. Digital PCR observed that this point mutation frequency dropped post-transplantation but remained low during maintenance therapy when the patient was leukemia-free. CONCLUSION: This suspected Li-Fraumeni syndrome case report with a likely pathogenic heterozygous TP53 variant expands the cancer genetic spectrum. Screening her family members for mutations facilitates identifying the optimal relative donor and avoids unnecessary treatment by monitoring TP53 germline mutations for minimal residual disease following hematopoietic stem cell transplantation. Its potential roles in hematological malignant tumor development and clinical pathogenic implications necessitate further probing.

Human umbilical cord mesenchymal stem cells attenuate diabetic nephropathy through the IGF1R-CHK2-p53 signalling axis in male rats with type 2 diabetes mellitus. / 人脐带间å 质干细胞通过IGF1R-CHK2-p53信号轴减轻2åž‹ç³–å°¿ç— é›„æ€§å¤§é¼ ç³–å°¿ç— è‚¾ç— .

Diabetes mellitus (DM) is a disease syndrome characterized by chronic hyperglycaemia. A long-term high-glucose environment leads to reactive oxygen species (ROS) production and nuclear DNA damage. Human umbilical cord mesenchymal stem cell (HUcMSC) infusion induces significant antidiabetic effects in type 2 diabetes mellitus (T2DM) rats. Insulin-like growth factor 1 (IGF1) receptor (IGF1R) is important in promoting glucose metabolism in diabetes; however, the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear. In this study, a DM rat model was induced with high-fat diet feeding and streptozotocin (STZ) administration and rats were infused four times with HUcMSC. Blood glucose, interleukin-6 (IL-6), IL-10, glomerular basement membrane, and renal function were examined. Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays. The expression of IGF1R, phosphorylated checkpoint kinase 2 (p-CHK2), and phosphorylated protein 53 (p-p53) was examined using immunohistochemistry (IHC) and western blot analysis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of 8-hydroxydeoxyguanosine (8-OHdG). Flow cytometry experiments were used to detect the surface markers of HUcMSC. The identification of the morphology and phenotype of HUcMSC was performed by way of oil red "O" staining and Alizarin red staining. DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane, increased the expression of IGF1 and IGF1R. IGF1R interacted with CHK2, and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells. When cisplatin was used to induce DNA damage, the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment. HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats. The expression of IGF1, IGF1R, p-CHK2, and p-p53, and the level of 8-OHdG in the DM group increased significantly compared with those in the control group, and decreased after HUcMSC treatment. Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage. HUcMSC infusion protected against kidney injury in DM rats. The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.

ALK fusion small cell transformation of lung adenocarcinoma: A case report and literature review. / ALKèžåˆè‚ºè ºç™Œå°ç»†èƒžè½¬åŒ–1ä¾‹å¹¶æ–‡çŒ®å¤ä¹ .

Patients with anaplastic lymphoma kinase (ALK) fusion lung adenocarcinoma may develop drug resistance after treatment with ALK-tyrosine kinase inhibitor (ALK-TKI), and the mechanisms of this resistance are not yet fully defined. The Affiliated Hospital of Zunyi Medical University admitted a patient who was resistant to ALK fusion after ALK-TKI treatment, leading to disease progression and subsequent biopsy indicating a transformation to small cell lung cancer in September 2021. The patient, a 54-year-old female, initially presented with symptoms of cough, sputum production, and chest pain for 4 months. Chest CT showed a neoplastic lesion in the posterior segment of the right upper lobe to right lower lobe with obstructive pneumonia, metastasis in the right lower lobe, increased and enlarged mediastinal and right hilar lymph nodes, and thickening of the right hilar soft tissue. Bronchoscopy and pathological biopsy confirmed the diagnosis of lung adenocarcinoma. The results of next-generation sequencing indicated that echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) fusion is associated with tumor protein 53 (TP53) and retinoblastoma 1 (RB1) gene mutations. The patient received second-generation ALK-TKI aletinib, achieving a progression-free survival of 11 months before disease progression suggested aletinib resistance. Subsequently, the third-generation ALK-TKI lorlatinib administered for one month without efficacy, resulting in rapid systemic disease progression. The neuron specific enolase (NSE) was significantly increased, and the patient developed new pleural, pericardial, intracranial, liver, and multiple bone metastases occurred in a short period. A second biopsy indicated small cell lung cancer. Modification of treatment regimen to chemotherapy combined with immunotherapy proved effective. The mechanisms of drug resistance of ALK-TKI treatment for advanced non-small cell lung cancer with ALK fusion are complex, and small cell transformation of pathological type is one such mechanism, although rare. Concurrent TP53 and RB1 gene mutations may be characteristic of this transformation. Elevated NSE can serve as a predictive serum marker for adenocarcinoma transforming to small cell carcinoma. Timely re-biopsy and selection of subsequent treatments based on different resistance mechanisms are crucial for comprehensive disease management.

Selective pressures of platinum compounds shape the evolution of therapy-related myeloid neoplasms.

Therapy-related myeloid neoplasms (t-MN) arise as a complication of chemo- and/or radiotherapy. Although t-MN can occur both in adult and childhood cancer survivors, the mechanisms driving therapy-related leukemogenesis likely vary across different ages. Chemotherapy is thought to induce driver mutations in children, whereas in adults pre-existing mutant clones are selected by the exposure. However, selective pressures induced by chemotherapy early in life are less well studied. Here, we use single-cell whole genome sequencing and phylogenetic inference to show that the founding cell of t-MN in children starts expanding after cessation of platinum exposure. In patients with Li-Fraumeni syndrome, characterized by a germline TP53 mutation, we find that the t-MN already expands during treatment, suggesting that platinum-induced growth inhibition is TP53-dependent. Our results demonstrate that germline aberrations can interact with treatment exposures in inducing t-MN, which is important for the development of more targeted, patient-specific treatment regimens and follow-up.

Nonviral CRISPR/Cas9 mutagenesis for streamlined generation of mouse lung cancer models.

Functional analysis in mouse models is necessary to establish the involvement of a set of genetic variations in tumor development. A modeling platform to facilitate and cost-effectively analyze the role of multiple genes in carcinogenesis would be valuable. Here, we present an innovative strategy for lung mutagenesis using CRISPR/Cas9 ribonucleoproteins delivered via cationic polymers. This approach allows the simultaneous inactivation of multiple genes. We validate the effectiveness of this system by targeting a group of tumor suppressor genes, specifically Rb1, Rbl1, Pten, and Trp53, which were chosen for their potential to cause lung tumors, namely small cell lung carcinoma (SCLC). Tumors with histologic and transcriptomic features of human SCLC emerged after intratracheal administration of CRISPR/polymer nanoparticles. These tumors carried loss-of-function mutations in all four tumor suppressor genes at the targeted positions. These findings were reproduced in two different pure genetic backgrounds. We provide a proof of principle for simplified modeling of lung tumorigenesis to facilitate functional testing of potential cancer-related genes.

Integrative genomic analysis reveals cancer-associated mutations in patients with ophthalmic tumors.

OBJECTIVE: Apart from the role of the retinoblastoma gene, the genomic events associated with poor outcomes in patients with ophthalmic tumors are poorly understood. METHODS: We retrospectively analyzed 48 patients with six types of ophthalmic tumors. We searched for high-frequency mutated genes and susceptibility genes in these patients using combined exome and transcriptome analysis. RESULTS: We identified four clearly causative genes (TP53, PTCH1, SMO, BAP1). Susceptibility gene analysis identified hotspot genes, including RUNX1, APC, IDH2, and BRCA2, and high-frequency gene analysis identified several genes, including TP53, TTN, and MUC16. Transcriptome analysis identified 5868 differentially expressed genes, of which TOP2A and ZWINT were upregulated in all samples, while CFD, ELANE, HBA1, and HBB were downregulated. Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that the phosphoinositide 3-kinase (PI3K)-Akt and Transcriptional misregulation in cancer signaling pathways may be involved in ophthalmic tumorigenesis. CONCLUSIONS: TP53 is clearly involved in ophthalmic tumorigenesis, especially in basal cell carcinoma, and the PI3K-Akt signaling pathway may be an essential pathway involved in ophthalmic tumorigenesis. RUNX1, SMO, TOP2A, and ZWINT are also highly likely to be involved in ophthalmic tumorigenesis, but further functional experiments are needed to verify the mechanisms of these genes in regulating tumorigenesis.

Evolving treatment paradigms for platinum-resistant ovarian cancer: An update narrative review.

Platinum-resistant ovarian cancer (PROC) refers to disease progression within 6 months after the completion of platinum-based chemotherapy. Historically, treatment options for PROC were limited with a poor prognosis and non-platinum single agent plus bevacizumab has been the mainstay of treatment. Fortunately, there have been notable advancements in recent years, leading to an advance in treatment paradigms for this challenging disease. Various combinations of chemotherapy, targeted agents such as poly (ADP-ribose) polymerase (PARP) inhibitors, and immunotherapy are being explored for an improved treatment outcome. Antibody-drug conjugates targeting folate receptor alpha, which deliver a cytotoxic payload directly to cancer cells, have emerged as a promising therapeutic approach for PROC. WEE1 inhibitors, such as adavosertib, function by inhibiting the WEE1 kinase activity, leading to premature entry of a cell into mitosis phase and thus increased DNA damage. It has been observed that cancer cells with TP53 mutations may be more sensitive to WEE1 inhibitors. Biomarker testing such as analysis of the expression level of folate receptor alpha or mutation in TP53 may be applicable for identifying patients who are more likely to respond to the specific therapy, enabling a more personalized treatment approach. This overview summarizes key clinical findings on the efficacy and safety of theses novel biomarker-driven therapeutic approaches.

Cellular zinc status alters chromatin accessibility and binding of p53 to DNA.

Zn2+ is an essential metal required by approximately 850 human transcription factors. How these proteins acquire their essential Zn2+ cofactor and whether they are sensitive to changes in the labile Zn2+ pool in cells remain open questions. Using ATAC-seq to profile regions of accessible chromatin coupled with transcription factor enrichment analysis, we examined how increases and decreases in the labile zinc pool affect chromatin accessibility and transcription factor enrichment. We found 685 transcription factor motifs were differentially enriched, corresponding to 507 unique transcription factors. The pattern of perturbation and the types of transcription factors were notably different at promoters versus intergenic regions, with zinc-finger transcription factors strongly enriched in intergenic regions in elevated Zn2+ To test whether ATAC-seq and transcription factor enrichment analysis predictions correlate with changes in transcription factor binding, we used ChIP-qPCR to profile six p53 binding sites. We found that for five of the six targets, p53 binding correlates with the local accessibility determined by ATAC-seq. These results demonstrate that changes in labile zinc alter chromatin accessibility and transcription factor binding to DNA.

Unveiling the role of circRBBP7 in myoblast proliferation and differentiation: A novel regulator of muscle development.

Muscle development is a multistep process regulated by diverse gene networks, and circRNAs are considered novel regulators mediating myogenesis. Here, we systematically analyzed the role and underlying regulatory mechanisms of circRBBP7 in myoblast proliferation and differentiation. Results showed that circRBBP7 has a typical circular structure and encodes a 13 -kDa protein. By performing circRBBP7 overexpression and RNA interference, we found that the function of circRBBP7 was positively correlated with the proliferation and differentiation of myoblasts. Using RNA sequencing, we identified 1633 and 532 differentially expressed genes (DEGs) during myoblast proliferation or differentiation, respectively. The DEGs were found mainly enriched in cell cycle- and skeletal muscle development-related pathways, such as the MDM2/p53 and PI3K-Akt signaling pathways. Further co-IP and IF co-localization analysis revealed that VEGFR-1 is a target of circRBBP7 in myoblasts. qRT-PCR and WB analysis further confirmed the positive correlation between VEGFR-1 and circRBBP7. Moreover, we found that in vivo transfection of circRBBP7 into injured muscle tissues significantly promoted the regeneration and repair of myofibers in mice. Therefore, we speculate that circRBBP7 may affect the activity of MDM2 by targeting VEGFR-1, altering the expression of muscle development-related genes by mediating p53 degradation, and ultimately promoting myoblast development and muscle regeneration. This study provides essential evidence that circRBBP7 can serve as a potential target for myogenesis regulation and a reference for the application of circRBBP7 in cattle genetic breeding and muscle injury treatment.

A case series of osseous metastases in patients with glioblastoma.

BACKGROUND: Extracranial metastases occur in <2% of cases of glioblastoma (GBM). When metastases do occur, bone is the most common destination. Herein, we review clinical characteristics of GBM patients with osseous metastases and evaluate both potential risk factors and prognostic significance. METHODS: Using an institutional database, we identified and retrospectively analyzed 6 patients with both GBM and osseous metastases. We collected data on patient demographics, tumor genetics, clinical courses, and outcomes. Given the rarity of metastatic GBM, we conducted historical comparisons using previously published literature. RESULTS: Five patients with osseous metastases (83%) were male, with a median age of 46 years at GBM diagnosis (range: 20-84). All patients had IDH-wildtype, MGMT promoter unmethylated GBM and 5 (83%) had alterations in TP53. All patients underwent surgical resection for GBM followed by radiation with concurrent and adjuvant temozolomide. Four patients (67%) received bevacizumab prior to bone metastasis diagnosis. Bone metastases were discovered at a median of 12.2 months (range: 5.3-35.2) after GBM diagnosis and 4.8 months after starting bevacizumab (range: 3.5-13.2). Three patients (50%) received immunotherapy. After osseous metastasis diagnosis, the median survival was 25 days (range: 13-225). CONCLUSION: In our cohort, most patients were male and young at the time of GBM diagnosis. All patients had IDH-wildtype, MGMT promoter unmethylated GBM, and most had alterations in TP53, which may be important for osseous metastasis. Most patients received bevacizumab, which has been associated with earlier metastasis. Osseous metastases of GBM occur and portend a dismal prognosis in an already aggressive malignancy.

Baicalin protects against hepatocyte injury caused by aflatoxin B1 via the TP53-related ferroptosis Pathway.

OBJECTIVE: Baicalin has antioxidative, antiviral, and anti-inflammatory properties. However, its ability to alleviate oxidative stress (OS) and DNA damage in liver cells exposed to aflatoxin B1 (AFB1), a highly hepatotoxic compound, remains uncertain. In this study, the protective effects of baicalin on AFB1-induced hepatocyte injury and the mechanisms underlying those effects were investigated. METHODS: Stable cell lines expressing CYP3A4 were established using lentiviral vectors to assess oxidative stress levels by conducting assays to determine the content of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD). Additionally, DNA damage was evaluated by 8-hydroxy-2-deoxyguanosine (8-OHdG) and comet assays. Transcriptome sequencing, molecular docking, and in vitro experiments were conducted to determine the mechanisms underlying the effects of baicalin on AFB1-induced hepatocyte injury. In vivo, a rat model of hepatocyte injury induced by AFB1 was used to evaluate the effects of baicalin. RESULTS: In vitro, baicalin significantly attenuated AFB1-induced injury caused due to OS, as determined by a decrease in ROS, MDA, and SOD levels. Baicalin also considerably decreased AFB1-induced DNA damage in hepatocytes. This protective effect of baicalin was found to be closely associated with the TP53-mediated ferroptosis pathway. To elaborate, baicalin physically interacts with P53, leading to the suppression of the expression of GPX4 and SLC7A11, which in turn inhibits ferroptosis. In vivo findings showed that baicalin decreased DNA damage and ferroptosis in AFB1-treated rat liver tissues, as determined by a decrease in the expression of γ-H2AX and an increase in GPX4 and SLC7A11 levels. Overexpression of TP53 weakened the protective effects of baicalin. CONCLUSIONS: Baicalin can alleviate AFB1-induced OS and DNA damage in liver cells via the TP53-mediated ferroptosis pathway. In this study, a theoretical foundation was established for the use of baicalin in protecting the liver from the toxic effects of AFB1.

Comparative Morphological and Molecular Genetic Characteristics of Cell and Tissue Strains of Experimental Rat Glioma 10-17-2 (Astrid-17).

In order to obtain models of gliomas of varying degrees of malignancy, we performed morphological and molecular genetic study of a tissue strain of glioma 10-17-2 (Astrid-17) obtained by intracranial passaging of tumor fragments of chemically induced rat brain tumor, and a cell strain isolated from it. More or less pronounced changes in the expression levels of Mki67, Trp53, Vegfa, and Gfap genes in the tissue and cell strain of glioma 10-17-2 (Astrid-17) compared with intact brain tissue were shown. The tissue model of glioma 10-17-2 (Astrid-17) according to the studied characteristics shows features of grade 3-4 astrocytoma and the cellular model - grade 2-3 astrocytoma.

Effect and mechanism of resveratrol on ferroptosis mediated by p53/SLC7A11 in oral squamous cell carcinoma.

OBJECTIVE: Resveratrol (Res) is a natural phytoestrogen with antitumor activity. This study sought to investigate the role of Res in ferroptosis in oral squamous cell carcinoma (OSCC). METHODS: Normal human oral keratinocyte (HOK)/oral OSCC (CAL-27/SCC-9) cell lines were treated with different doses of Res. Res toxicity was determined by MTT assay, with half maximal inhibitory concentration values of Res on CAL-27 and SCC-9 cells calculated. Cell viability/colony formation efficiency/migration/invasion/cycle were assessed by CCK-8/colony formation assay/transwell assay/flow cytometry. The expression of p53 protein in the nucleus and cytoplasm, glutathione peroxidase 4 (GPX4) expression, and SLC7A11 messenger RNA (mRNA) and protein expression levels were determined by Western blot and RT-qPCR. Fe2+ content, reactive oxygen species (ROS) level, reduced glutathione (GSH), and lactate dehydrogenase (LDH) release were assessed. RESULTS: Medium- to low-dose Res had no toxic effect on HOK cells, while high-dose Res markedly reduced HOK cell viability. Res significantly suppressed the viability of OSCC cells (CAL-27 and SCC-9). Res inhibited OSCC cell colony formation/migration/invasion, and induced G1 phase arrest. Res caused the translocation of p53 protein to the nucleus, obviously increased Fe2+ content, ROS level and LDH release, decreased GSH content and GPX4 protein expression, and induced ferroptosis. Down-regulation of p53 partially reversed the inhibitory effects of Res on CAL-27 cell malignant behaviors. Res inhibited SLC7A11 transcription by promoting p53 entry into the nucleus. SLC7A11 overexpression negated the the regulatory effects of p53 knockout on the role of Res in OSCC cell malignant behaviors and ferroptosis. CONCLUSION: Res accelerated ferroptosis and inhibited malignant behaviors in OSCC cells by regulating p53/SLC7A11.

Patritumab deruxtecan in HER2-negative breast cancer: part B results of the window-of-opportunity SOLTI-1805 TOT-HER3 trial and biological determinants of early response.

Patritumab deruxtecan (HER3-DXd) exhibits promising efficacy in breast cancer, with its activity not directly correlated to baseline ERBB3/HER3 levels. This research investigates the genetic factors affecting HER3-DXd's response in women with early-stage hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer. In the SOLTI-1805 TOT-HER3 trial, a single HER3-DXd dose was administered to 98 patients across two parts: 78 patients received 6.4 mg/kg (Part A), and 44 received a lower 5.6 mg/kg dose (Part B). The CelTIL score, measuring tumor cellularity and infiltrating lymphocytes from baseline to day 21, was used to assess drug activity. Part A demonstrated increased CelTIL score after one dose of HER3-DXd. Here we report CelTIL score and safety for Part B. In addition, the exploratory analyses of part A involve a comprehensive study of gene expression, somatic mutations, copy-number segments, and DNA-based subtypes, while Part B focuses on validating gene expression. RNA analyses show significant correlations between CelTIL responses, high proliferation genes (e.g., CCNE1, MKI67), and low expression of luminal genes (e.g., NAT1, SLC39A6). DNA findings indicate that CelTIL response is significantly associated with TP53 mutations, proliferation, non-luminal signatures, and a distinct DNA-based subtype (DNADX cluster-3). Critically, low HER2DX ERBB2 mRNA, correlates with increased HER3-DXd activity, which is validated through in vivo patient-derived xenograft  models. This study proposes chemosensitivity determinants, DNA-based subtype classification, and low ERBB2 expression as potential markers for HER3-DXd activity in HER2-negative breast cancer.

TUSC3, p53 and p21 genetic association with development of oral submucous fibrosis and oral squamous cell carcinoma among addictive tobacco chewers of Pakistan.

BACKGROUND: This study delves into the intricate landscape of oral cancer, a global concern with a high incidence in Asian countries. We focus on oral squamous cell carcinoma (OSCC), primarily driven by the consumption of betel nut and its derivatives. OSCC often arises from premalignant lesions like oral submucous fibrosis (OSF). In Pakistan, OSCC is prevalent among men due to various addictive substances, including smokeless tobacco and chewing materials. Mutations in tumor suppressor genes, such as TP53 and p21, play crucial roles in this malignancy's development. We also explore the involvement of TUSC3 gene deletion in OSCC and OSF. METHODS: In this study we investigated demographics, TUSC3 gene expression, deletion analysis, and TP53 and p21 genetic alterations in OSCC and OSF patients (blood and tissue of 50 samples in each condition) who had tobacco derivates usage history. The association analysis was carried out mainly through PCR based genotyping. RESULTS: The study's patient cohort (OSCC and OSF) displayed a wide age range from 13 to 65 years (Mean = 32.96 years). Both conditions were more prevalent in males, with a male-female ratio of approximately 2.5:1. Chewing habits analysis revealed high frequencies of gutka use in both OSF and OSCC patients. TUSC3 expression analysis in OSCC cell lines indicated significant downregulation. Genotyping showed no TUSC3 deletion in OSF cases, but a deletion rate of over 22% in OSCC tissue samples. Analysis supported a significant association of TUSC3 deletion with OSCC development but not with OSF. Polymorphism in p53 exon 4 and p21 (rs1801270) were significantly associated with both OSCC and OSF, adding to their pathogenesis. Our findings further revealed a strong correlation between TUSC3 deletion and the excessive use of tobacco and related products, shedding light on the genetic underpinnings of OSCC development. CONCLUSIONS: Notably, our study provides a crucial insight into genetic aspects underlying OSCC and OSF in response of addictive consumption of areca nut, betel quid, and tobacco derivatives. A significant association between TUSC3 deletion and OSCC development, along with polymorphisms in TP53 and p21, underscores the importance of further research into the molecular mechanisms driving oral cancer progression for improved diagnosis and treatment outcomes.

Determinants of p53 DNA binding, gene regulation, and cell fate decisions.

The extent to which transcription factors read and respond to specific information content within short DNA sequences remains an important question that the tumor suppressor p53 is helping us answer. We discuss recent insights into how local information content at p53 binding sites might control modes of p53 target gene activation and cell fate decisions. Significant prior work has yielded data supporting two potential models of how p53 determines cell fate through its target genes: a selective target gene binding and activation model and a p53 level threshold model. Both of these models largely revolve around an analogy of whether p53 is acting in a "smart" or "dumb" manner. Here, we synthesize recent and past studies on p53 decoding of DNA sequence, chromatin context, and cellular signaling cascades to elicit variable cell fates critical in human development, homeostasis, and disease.