P53 Protein Research Articles

Exploring the Functional Landscape of the p53 Regulatory Domain: The Stabilizing Role of Post-Translational Modifications.

This study focuses on the intrinsically disordered regulatory domain of p53 and the impact of post-translational modifications. Through fully atomistic explicit water molecular dynamics simulations, we show the wealth of information and detailed understanding that can be obtained by varying the number of phosphorylated amino acids and implementing a restriction in the conformational entropy of the N-termini of that intrinsically disordered region. The take-home message for the reader is to achieve a detailed understanding of the impact of phosphorylation with respect to (1) the conformational dynamics and flexibility, (2) structural effects, (3) protein interactivity, and (4) energy landscapes and conformational ensembles. Although our model system is the regulatory domain p53 of the tumor suppressor protein p53, this study contributes to understanding the general effects of intrinsically disordered phosphorylated proteins and the impact of phosphorylated groups, more specifically, how minor changes in the primary sequence can affect the properties mentioned above.

Delay induced Hopf bifurcation and its control in a fractional p53 protein oscillator model

The p53 protein is essential for cancer prevention. Research on p53 mathematical models is popular since its oscillatory dynamics were observed. However, there is little research on fractional-order p53 oscillators, as well as on Hopf bifurcation control. We therefore introduce fractional-order into a p53 oscillator model and propose a delayed state feedback bifurcation controller. The stability of positive equilibrium and the existence of Hopf bifurcation are studied analytically regarding delay as the bifurcation parameter in both controlled and uncontrolled scenarios. Numerical simulations are consistent with the analytical results. We reveal that a smaller fractional-order facilitates the stability of fixed point and a larger feedback gain advances the Hopf bifurcation point. The work may inspire cancer therapy by artificially controlling the occurrence of p53 oscillations.

Effects of dietary salidroside on intestinal health, immune parameters and intestinal microbiota in largemouth bass (Micropterus salmoides)

The largemouth bass has become one of the economically fish in China, according to the latest China Fishery Statistical Yearbook. The farming scale is constantly increasing. Salidroside has been found in past studies to have oxidative stress reducing and immune boosting properties. In this study, the addition of six different levels of salidroside supplements were 0、40、80、120、160 and 200 mg/kg. A 56-day feeding trial was conducted to investigate the effects of salidroside on the intestinal health, immune parameters and intestinal microbiota composition of largemouth bass. Dietary addition of salidroside significantly affected the Keap-1β/Nrf-2 pathway as well as significantly increased antioxidant enzyme activities resulting in a significant increase in antioxidant capacity of largemouth bass. Dietary SLR significantly reduced feed coefficients. The genes related to tight junction proteins (Occludin, ZO-1, Claudin-4, Claudin-5) were found to be significantly upregulated in the diet supplemented with salidroside, indicating that salidroside can improve the intestinal barrier function (p < 0.05). The dietary administration of salidroside was found to significantly reduce the transcription levels of intestinal tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) (p < 0.05). Furthermore, salidroside was observed to reduce the transcription levels of intestinal apoptosis factor Bcl-2 associated death promoter (BAD) and recombinant Tumor Protein p53 (P53) (p < 0.05). Concomitantly, the beneficial bacteria, Fusobacteriota and Cetobacterium, was significantly increased in the SLR12 group, while that of pathogenic bacteria, Proteobacteria, was significantly decreased (p < 0.05). In conclusion, the medium-sized largemouth bass optimal dosage of salidroside in the diet is 120mg/kg−1.

ESF1 positively regulates MDM2 and promotes tumorigenesis

Eighteen S rRNA factor 1 (ESF1) is a predominantly nucleolar protein essential for embryogenesis. Our previous studies have suggested that Esf1 is a negative regulator of the tumor suppressor protein p53. However, it remains unclear whether ESF1 contributes to tumorigenesis. In this current research, we find that increased ESF1 expression correlates with poor survival in multiple tumors including pancreatic cancer. ESF1 is able to regulate cell proliferation, migration, DNA damage-induced apoptosis, and tumorigenesis. Mechanistically, ESF1 physically interacts with MDM2 and is essential for maintaining the stability of MDM2 protein by inhibiting its ubiquitination. Additionally, ESF1 also prevented stress-induced stabilization of p53 in multiple cancer cells. Hence, our findings suggest that ESF1 is a potent regulator of the MDM2-p53 pathway and promotes tumor progression.

Lovastatin Combination Therapy Increases the Survival and Proliferation of Rat Bone Marrow-Derived Mesenchymal Stem Cells Against the Inflammatory Activity of Lipopolysaccharide.

Oxidative stress hurts the survival of transplanted mesenchymal stem cells (MSCs). Lipopolysaccharide (LPS) preconditioning inhibits apoptotic death in MSCs. Also, Lovastatin's protective effect was reported on MSCs. Here, we investigated the potential of LPS and Lovastatin combination therapy on the survival and proliferation of MSCs. MSCs harvested from adult rats (240-260 g) femur and tibia bone marrow. Third passage MSCs were divided into 6 groups control group, LPS, LPS + Lovastatin (10 and 15 µM), and Lovastatin (10 and 15 µM). Cell survival and proliferation were assessed using an MTT assay 24 h after LPS, Lovastatin, or LPS + Lovastatin treatment. Also, Malondialdehyde (MDA) as a lipid peroxidation marker and antioxidant enzymes such as Glutathione peroxidase (GPX) and Superoxide dismutase (SOD) activity levels evaluated. Finally, the expression level of tumor protein P53 (P53) and octamer-binding transcription factor 4 (OCT4) genes were measured by qRT-PCR test. Lovastatin 10 μM potentiated proliferation and survival of MSCs. It can increase the activity of GPX and SOD. 10 µM Lovastatin could not affect MDA amounts but decreased the expression levels of P53 and Oct4 significantly. Nevertheless, treatment with LPS reduced the survival and proliferation of MSCs, along with a significant reduction in GPX activity. LPS + Lovastatin could increase SOD activity, however, GPX enzyme activity and MSCs proliferation did not change so, and it was not effective. We propose Lovastatin at the dose of 10 µM as a suitable combination agent to increase the survival and proliferation of MSCs in oxidative stress conditions.

P-606 Maintenance of telomere length through autophagy and androgen receptor inhibition in infertile individuals with differences of sex development (DSD)

Abstract Study question What are the molecular mechanisms underlying genome instability concomitant with increased telomere length (TL) in individuals with DSD? Summary answer Low autophagy activity and androgen receptor signaling stabilize GAR1, a telomerase-specific protein, leading to an increase in TL in DSD cells. What is known already Increased genome instability is linked to infertility, and compromised telomere maintenance is associated with genome instability. Individuals with DSD, characterized by dysgenic gonads and a high risk of Germ Cell Tumor (GCT) development, exhibit concurrent genome instability, increased TL, and deregulated Androgen Receptor (AR) signaling. Telomeric DNA damage promotes autophagy, which induces cell death and prevents propagation of replication crisis and tumorigenesis. We previously demonstrated that inhibition of autophagy, a conservative process of protein degradation, led to TL increase in cell lines derived from individuals with DSD, but the underlying mechanisms remain unclear. Study design, size, duration 112 individuals with DSD, including Swyer syndrome (46,XY females), Complete Androgen Insensitivity Syndrome (CAIS 46,XY females), Turner (45,X0 females), and Mixed Gonadal Dysgenesis (MGD 45,X0/46,XY females and males) were enrolled into study during routine praxis in our clinic. The samples were collected with written patients consent. A control group included fertile women and men, when appropriate, of comparable age. Samples underwent standard genetic and histological characterization. Lymphoblastoid cell lines were used for functional studies. Participants/materials, setting, methods Study groups comprised individuals with CAIS (n = 19); Swyer (n = 8); MGD (n = 12); Turner (n = 23) with mosaic (n = 12), with chr. X/Y deletions (n = 8), with X-isochr./idiocentric/marker chr. (n = 23) syndromes. Blood samples were collected for DNA, RNA and protein isolation from leukocytes. Additionally, individuals with DSD who underwent gonadectomy formed an additional group with histologically proven GCT (DSD-GCT, n = 7). Gonadal tissue was provided by the tissue bank. Samples were analyzed using quantitative real-time PCR (qRT-PCR), immunoblotting, and mass spectrometry. Main results and the role of chance Leukocytes from Swyer (p = 0,0069), Turner (p = 0,0064), and MGD without GCT (p = 0,05) groups exhibited a 1,5-folds increase in TL, diminished with GCT (p = 0,003). The RNA component of telomerase, TERC, was inhibited two times in Swyer (p = 0,0417). Proteomic analysis identified a telomerase protein GAR1 accumulation in Swyer, but downregulated in GCT group together with AR upregulation (p = 0,0379). Immunoblotting confirmed a two-fold increase of GAR1 in Swyer (p = 0,0022) and Turner (p = 0,0401), while GAR1 decreased in all DSD samples (p = 0,0455). GAR1 protein increased stability, not due to upregulated transcription, and promoted TL since we illustrated GAR1 accumulation within 72h of BafilomycinA1 treatment inhibiting autophagy. This treatment induced telomerase activity within 24h. Further autophagy inhibition caused accumulation of DNA damage in DSD cells, measured by γH2AX levels labeling double strand brakes (p = 0,0286). Dysgenic gonadal tissue analysis also showed a negative correlation between autophagy and TL-specific gene expression, with LC3 (p = 0,0341) and P62 (p = 0,0342) increased in all DSD samples, and proteins LC3 (p = 0,0298) and P62 (p = 0,0237) upregulated, and GAR1 (p = 0,0432) inhibited exclusively in Swyer group. Inhibition of AR increased TL (p = 0,0357) together with GAR1 (p = 0,0125) in DSD group at 19h, which was associated with a consecutive γH2AX upregulation (p = 0,0489) at 24h with Enzalutamide. Limitations, reasons for caution This study is based on a limited number of samples from the individuals with rare genetic syndromes, some observed only in 1 out of 10,000 clinical cases. Therefore, in vitro study models are recommended for further research. Wider implications of the findings The study reveals gene expression patterns and molecular regulatory mechanisms associated with DSD and GCT risk. The data suggest possibilities for prophylactic treatment of DSD individuals and new diagnostic approaches of GCT using peripheral blood. The study also emphasizes the importance of addressing genome integrity in infertility research. Trial registration number NA

Moringa oleifera seed methanol extract with consolidated antimicrobial, antioxidant, anti-inflammatory, and anticancer activities.

The wide biological activity of the Moringa oleifera represents a potential opportunity for developing selective cancer treatment drugs. The bioactive phytochemicals in Moringa seed extract (MSE) indicated large numbers of phytochemicals (21 compounds) with dominant abundance for cycloisolongifolene, 8,9-dehydro-9-vinyl, and chamazulene accounting for 12.7% and 12.19% of the total detected compounds. The MSE showed a potent anticancer effect toward Caco-2, MDA, and HepG-2 cells with half-maximal inhibitory concentration (IC50) values of 9.15±1.18, 4.85±0.11, and 7.36±0.22µg/mL, respectively, with higher safety (≥31-folds) toward normal human cells (IC50 of 150.7±11.11µg/mL). It appears that MSE stimulates selective-dose-dependent cell shrinkage, and nuclear condensation in the tumor cells, which finally induces the apoptosis pathway to increase its anticancer action. Additionally, MSE showed a potent capability to stimulate cell cycle arrest in both main checkpoint phases (G0/G1 and G2/M) of cell population growth. The apoptotic death stimulation was confirmed through upregulation of tumor protein p53 (p53) and cyclin-dependent kinase inhibitor p21 (p21) expression by more than three- to sixfold and downregulation of B-cell lymphoma 2 expression (threefold) in MSE-treated cells compared to 5-fluorouracil (5-FU)-treated tumor cells. Furthermore, the MSE revealed strong anti-inflammatory activity with significant antioxidant activity by lowering nitric oxide levels and enhancing the superoxide dismutase activity. On the other hand, the MSE revealed broad-spectrum antibacterial activity in a dose-dependent manner against Staphylococcus aureus minimum inhibitory concentration (MIC of 1.25mg/mL), followed by Salmonella typhimurium (MIC of 1.23mg/mL), whereas Escherichia coli was the least sensitive to MSE activity (MIC of 22.5mg/mL) with significant antibiofilm activity against sensitive pathogens.

Engagement of specific intracellular pathways in the inflammation-based reprotoxicity effect of small-size silver nanoparticles on spermatogonia and spermatocytes invitro cell models

Male infertility is a serious ongoing problem, whose causes have not yet been clearly identified. However, since human exposure to silver nanoparticles (AgNPs) has recently increased due to their beneficial properties, the present study aimed to determine the impact of small-size AgNPs on mouse spermatogonia (GC-1 spg) and spermatocytes [GC-2 spd(ts)] in vitro models as well as the ability of these nanostructures to induce inflammation. The results showed a significant dose- and time-dependent decrease in the metabolic activity in both cell models, which was correlated with an increase in the intracellular ROS level. Moreover, increased activity of caspase-9 and -3, together with enhanced expression of CASP3 and p(S15)-p53 proteins, was detected. Further studies indicated a decrease in ΔΨm after the AgNP-treatment, which proves induction of apoptosis with engagement of an intrinsic pathway. The PARP1 protein expression, the activity and protein expression of antioxidant enzymes, the GSH level, and the increased level of p-ERK1/2 indicate not only the engagement of DNA damage but also the occurrence of oxidative stress. The small-size AgNPs were able to induce inflammation, proved by increased protein expression of NF-κB, p-IκBα, and NLRP3, which indicate damage to spermatogonia and spermatocyte cells. Moreover, the PGC-1α/PPARγ and NRF2/Keap1 pathways were engaged in the observed effect. The spermatogonial cells were characterized by a stronger inflammation-based response to AgNPs, which may be correlated with the TNFα/TRAF2-based pathway. Summarizing, the obtained results prove that AgNPs impair the function of testis-derived cells by inducing the redox imbalance and inflammation process; therefore, these NPs should be carefully implemented in the human environment.

Mismatch repair deficiency and abnormal p53 expression has significant predictive value for progesterone resistance and endometrial tumorigenesis in patients with endometrial atypical hyperplasia receiving fertility-preserving treatment

ObjectiveThis study aimed to evaluate the prognostic ability of mismatch repair deficiency (MMR-d) and abnormal p53 expression (p53abn) in patients with endometrial atypical hyperplasia (EAH) who underwent fertility-preserving treatment. MethodsThis retrospective study evaluated 51 patients with EAH who underwent fertility-sparing treatment. Endometrial biopsy specimens obtained before hormone therapy were collected and used for immunohistochemical staining for MMR and p53 proteins. Response, relapse, and progression rates were assessed based on age, body mass index, diabetes, polycystic ovary syndrome, reproductive history, MMR status, and p53 status. ResultsOverall, 11/51 (21.6%) patients had loss of MMR proteins and 6/51 (11.8%) had p53abn. Patients with MMR-d had lower complete response (CR) rates than those with normal staining patients at 12 months after initial treatment (p = 0.049). Patients with MMR-d had significantly higher relapse rates than those with MMR-p at the 1-year follow-ups after achieving CR (p = 0.035). Moreover, patients with MMR-d had a higher incidence of disease progression at 2, 3, and 4 years after fertility-sparing treatment (p = 0.001, p = 0.01 and p = 0.035, respectively). Patients with p53abn had higher relapse rates than those with p53wt at the 1- and 2-year follow-ups after achieving CR (p = 0.047 and p = 0.036, respectively). Moreover, patients with p53abn had a higher incidence of disease progression at 3 and 4 years after fertility-sparing treatment (p = 0.02 and p = 0.049, respectively). ConclusionsEAH patients with MMR-d and p53abn have a significantly higher risk of disease relapse and progression. Thus, MMR-d and p53abn may be used as predictive biomarkers of progestin resistance and endometrial tumorigenesis in EAH.

Ginsenoside Rb1 Inhibits the Proliferation of Lung Cancer Cells by Inducing the Mitochondrial-mediated Apoptosis Pathway.

Lung cancer is one of the more common malignant tumors posing a great threat to human life, and it is very urgent to find safe and effective therapeutic drugs. The antitumor effect of ginsenosides has been reported to be a treatment with a strong effect and a high safety profile. This paper aimed to investigate the inhibitory effect of ginsenoside Rb1 on 95D and NCI-H460 lung cancer cells and its pathway to promote apoptosis. We performed the CCK-8 assay, fluorescence staining assay, flow cytometry, scratch healing assay, and Transwell assay to detect the effects of different concentrations of ginsenoside Rb1 on the antitumor activity of 95D and NCI-H460 cells and Western Blot detected the mechanism of antitumor effect. Ginsenoside Rb1 treatment significantly increased the inhibition and apoptosis rates of 95D and NCIH460 cells and inhibited the cell cycle transition from S phase to G2/M. Rb1 induces apoptosis by altering the levels of P53, Bax, Cyto-c, Caspase-8, Caspase-3, Cleaved Caspase-3, Bcl-2, MMP-2, and MMP-9 proteins and activating the external apoptotic pathway. Ginsenoside Rb1 inhibits proliferation and migration and induces apoptosis of 95D and NCI-H460 lung cancer cells by regulating the mitochondrial apoptotic pathway to achieve antitumor activity.

Diagnostic Impact of P53,P16, Retinoblastoma, and Bcl-2 Proteins in Human Papillomavirus-Associated Squamous Cell Carcinoma Cervical Lesions

Diagnostic Impact of P53,P16, Retinoblastoma, and Bcl-2 Proteins in Human Papillomavirus-Associated Squamous Cell Carcinoma Cervical Lesions

5-aminolevulinic acid photodynamic therapy protects against UVB-induced skin photoaging: A DNA-repairing mechanism involving the BER signalling pathway.

Low-dose 5-aminolevulinic acid photodynamic therapy (ALA-PDT) has been used to cope with skin photoaging, and is thought to involve DNA damage repair responses. However, it is still unknown how low-dose ALA-PDT regulates DNA damage repair to curb skin photoaging. We established a photoaging model using human dermal fibroblasts (HDFs) and rat skin. RNA-sequencing (RNA-seq) analysis was conducted to identify differentially expressed genes (DEGs) in HDFs before and after low-dose ALA-PDT treatment, followed by bioinformatics analysis. Senescence-associated β-galactosidase (SA-β-gal) staining was employed to assess skin aging-related manifestations and Western blotting to evaluate the expression of associated proteins. A comet assay was used to detect cellular DNA damage, while immunofluorescence to examine the expression of 8-hydroxy-2'-deoxyguanosine (8-oxo-dG) in cells and skin tissues. In both invivo and invitro models, low-dose ALA-PDT alleviated the manifestations of ultraviolet B (UVB)-induced skin photoaging. Low-dose ALA-PDT significantly reduced DNA damage in photoaged HDFs. Furthermore, low-dose ALA-PDT accelerated the clearance of the photoproduct 8-oxo-dG in photoaged HDFs and superficial dermis of photoaged rat skin. RNA-seq analysis suggested that low-dose ALA-PDT upregulated the expression of key genes in the base excision repair (BER) pathway. Further functional validation showed that inhibition on BER expression by using UPF1069 significantly suppressed SA-β-gal activity, G2/M phase ratio, expression of aging-associated proteins P16, P21, P53, and MUTYH proteins, as well as clearance of the photoproduct 8-oxo-dG in photoaged HDFs. Low-dose ALA-PDT exerts anti-photoaging effects by activating the BER signalling pathway.

Shenling Baizhu Decoction treats ulcerative colitis of spleen-deficiency and dampness obstruction types by targeting ‘gut microbiota and galactose metabolism-bone marrow’ axis

Ethnopharmacological relevanceShenlin Baizhu Decoction (SLBZD), which comes from ‘Taiping Huimin Heji Ju Fang’, belongs to a classical prescription for treating spleen deficiency and dampness obstruction (SQDDS)-type ulcerative colitis (UC) in traditional Chinese medicine. However, the mechanism of SLBZD in treating UC with SQDDS remains unclear. Aim of the studyThis study aims to investigate the mechanism of SLBZD against SQDDS-type UC of based on the "gut microbiota and metabolism - bone marrow" axis to induce endogenous bone marrow mesenchymal stem cells (BMSCs) homing. Materials and methodsUltra-performance liquid chromatography- mass spectrometry was used to analysis of SLBZD qualitatively. The efficacy of SLBZD in SQDDS-type UC was evaluated based on the following indicators: the body weight, colon length disease activity index (DAI) score, Haemotoxylin and Eosin (H&E) pathological sections, and intestinal permeability proteins (occluding and ZO-1). 16S rRNA gene sequencing and non-target metabolomics were performed to identify gut microbiota changes and its metabolites in feces, respectively. BMSCs in each group was collected, cultured, and analyzed. Optimal passaged BMSCs were injected by tail vein into UC rats of SQDDS types. BMSCs homing to the colonic mucosal tissue was observed by immunofluorescent. Finally, the repairing effect of BMSCs homing to the colonic mucosal tissue after SLBZD treatment was analyzed by transmission electron microscopy, qRT-PCR, and immunohistochemistry. ResultsSLBZD effectively improved the colonic length and the body weight, scores, reduced DAI and H&E scores, and increased the expression of the intestinal permeability proteins, including occluding and ZO-1, to treat SQDDS-type UC. After SLBZD treatment, the α-diversity and β-diversity of the gut microbiota were improved. The differential microbiota was screened as Aeromonadaceae, Lactobacillaceae, and Clostridiaceae at the family level, and Aeromonas, Lactobacillus, Clostridium_sensu_stricto_1 at the genus level. Meanwhile, the main metabolic pathway was the galactose metabolism pathway. SLBZD treatment timely corrected the aberrant levels of β-galactose in peripheral blood and bone marrow, senescence-associate-β-galactosidase in BMSCs, and galactose kinase-2, galactose mutase, and galactosidase beta-1 in peripheral blood to further elevate the expression levels of SA proteins (p16, p53, p21, and p27) in BMSCs. The Spearman’s correlation analysis demonstrated the relationship between microbiota and metabolism, and the relationship between the galactose metabolism pathway and SA proteins. After BMSCs in each group injection via the tail vein, the pharmacodynamic effects were consistent with those of SLBZD in SQDDS-type UC rats. Furthermore, BMSCs have been homing to colonic mucosal tissue. BMSCs from the SLBZD treatment group had stronger restorative effects on intestinal permeability function due to increasing protein and mRNA expressions of occludin and ZO-1, and decreasing the proteins and mRNA expressions of SDF-1 and CXCR4 in colon. ConclusionsSLBZD alleviated the damaged structure of gut microbiota and regulated their metabolism, specifically the galactose metabolism, to treat UC of SDDOS types. SLBZD treatment promotes endogenous BMSCs homing to colonic mucosal tissue to repaire the intestinal permeability. The current exploration revealed an underlying mechanism wherein SLBZD activates endogenous BMSCs by targeting ‘the gut microbiota and its metabolism-bone marrow’ axis and repairs colonic mucosal damage for to treat SDDOS-type UC.

Simultaneous immunodetection of multiple cervical cancer biomarkers based on a signal-amplifying redox probes/polyethyleneimine-coated gold nanoparticles/2D tungsten disulfide/graphene oxide nanocomposite platform

To advance cervical cancer diagnostics, we propose a state-of-the-art label-free electrochemical immunosensor designed for the simultaneous detection of multiple biomarker proteins (p16INK4a, p53, and Ki67). This immunosensor is constructed using a polyethyleneimine-coated gold nanoparticles/2D tungsten disulfide/graphene oxide (PEI-AuNPs/2D WS2/GO) composite-modified three-screen-printed carbon electrode (3SPCE) array. The 2D WS2/GO hybrid provides a large specific surface area for supporting well-dispersed PEI-AuNPs and adsorbed redox-active species, enhancing overall performance. The PEI-AuNPs-decorated 2D WS2/GO composite not only improves electrode conductivity but also increases the antibody loading capacity. Redox-active species, including Cd2+ ions, 2,3-diaminophenazine (DAP), and methylene blue (MB), serve as distinct signaling compounds to quantitatively detect the cervical cancer biomarkers p16INK4a, p53, and Ki67, respectively. Additionally, the immunosensor demonstrates the detection with high sensitivity, good storage stability, high selectivity, and acceptable reproducibility. This immunosensor demonstrates a good linear relationship with the logarithm of protein concentrations. Additionally, the immunosensor also demonstrates high sensitivity, good storage stability, high selectivity, and acceptable reproducibility. Our promising results and the successful application of the immunosensor in detecting three tumor markers in human serum highlight its potential for clinical diagnosis of cervical cancer.

Incense-burning smoke ingredient Auramine enhances lincRNA-p21 expression for chemosensitization in p53-mutated non-small cell lung cancer

Incense-burning smoke is a deleterious air pollutant that initiates cytotoxic effects by inducing apoptosis in lung epithelial cells and also acts as a risk factor for lung cancers. Auramine, an ingredient of incense smoke, has been implicated in tumor progression and cellular sensitivity in non-small cell lung cancer (NSCLC) towards anti-cancer agents through unclear mechanisms. Tumor protein p53 (TP53)-activated long intergenic non-coding RNA-p21 (lincRNA-p21) undertakes a pivotal role in regulating cell apoptosis and chemosensitivity. TP53 mutations prevalent in 50% of NSCLC, contribute to diminished therapeutic efficacy. However, the influence of auramine on chemotherapy-induced lincRNA-p21 expression and apoptosis in NSCLC with different TP53 genetic statuses remains unexplored. This study disclosed that both wild-type p53 (wtp53) and mutant p53 (mutp53) mediate lincRNA-p21 expression, albeit through distinct promoter enhancers, p53-response element (p53RE) and non-B DNA structure G-quadruplex (GQ), respectively. Intriguingly, auramine functions as an effective stabilizer of the GQ structure, augmenting mutp53-mediated lincRNA-p21 expression and enhancing apoptosis and cellular sensitivity to chemotherapy in mutp53-expressing NSCLC cells. These findings suggest a mechanism by which mutp53, in the presence of auramine, is endowed with tumor-suppressing function akin to wtp53, thereby aiding in combating chemoresistance in NSCLC cells harboring TP53 mutations. Environmental implicationsIndoor air pollution from incense burning impacts more than 1.5 billion people, and auramine has been considered a unique carcinogen in the incense burning smoke, potentially implicated in the tumorigenesis of lung cancers. However, the effect of auramine on the therapeutic response of cancer cells to chemotherapy remains unclear. This study revealed a novel mechanism by which auramine, via stabilizing GQ structure to enhance lincRNA-p21 expression, promotes chemotherapy-induced apoptosis in mutp53-expressing NSCLC cells, which suggests that mutp53-expressing NSCLC patients with incense smoke-exposure history may show response to chemotherapeutic agents.

BRD4 plays an antiaging role in the senescence of renal tubular epithelial cells.

Age-related kidney failure is often induced by a decrease in the bioavailability of tubular epithelial cells in elderly chronic kidney disease (CKD) patients. BRD4, an epigenetic regulator and a member of the bromodomain and extraterminal (BET) protein family, acts as a super-enhancer (SE) organizing and regulating genes expression during embryogenesis and cancer development. But the physiological function of BRD4 in normal cells has been less studied. This study aimed to research certain biological roles of BRD4 in the process of normal cell aging and discuss the potential mechanisms. In this study, we investigated the biological functions of BRD4 proteins in the aging of renal tubular cells. At first, we used a D-galactose (D-gal) and BRD4 inhibitor (Abbv-075) to replicate kidney senescence in vivo. D-gal and Abbv-075 were then used to measure the aging-related changes, such as changes in cell cycle, β-galactosidase activity, cell migration, and p16 protein expression in vitro. At last, we knocked down and over-expressed BRD4 to investigate the aging-related physiological phenomena in renal tubular cells. In vitro, D-gal treatment induced noticeable aging-related changes such as inducing cell apoptosis and cell cycle arrest, increasing β-galactosidase activity as well as up-regulating p16 protein expression in primary human tubular epithelial cells. In the aging mice model, D-gal significantly induced renal function impairment and attenuated BRD4 protein expression. At the same time, the BRD4 inhibitor (Abbv-075) was able to mimic D-gal-induced cell senescence. In vivo, Abbv-075 also decreased kidney function and up-regulated p21 protein expression. When we knocked down the expression of BRD4, the senescence-associated β-galactosidase (SA-β-gal) activity increased dramatically, cell migration was inhibited, and the proportion of cells in the G0/G1 phase increased. Additionally, the knockdown also promoted the expression of the senescence-related proteins p16. When the renal tubular cells were overexpressed with BRD4, cell aging-related indicators were reversed in the D-gal-induced cell aging model. BRD4 appears to have an active role in the aging of renal tubular cells in vivo and in vitro. The findings also suggest that BRD4 inhibitors have potential nephrotoxic effects for oncology treatment. BRD4 may be a potential therapeutic biomarker and drug target for aging-related kidney diseases, which warrants additional studies.

Functional consequences of a p53-MDM2-p21 incoherent feedforward loop.

Genetically identical cells can respond heterogeneously to cancer therapy, with a subpopulation of cells often entering a temporarily arrested treatment-tolerant state before repopulating the tumor. To investigate how heterogeneity in the cell cycle arrest protein p21 arises, we imaged the dynamics of p21 transcription and protein expression along with those of p53, its transcriptional regulator, in single cells using live cell fluorescence microscopy. Surprisingly, we found that the rate of p21 transcription depends on the change in p53 rather than its absolute level. Through combined theoretical and experimental modeling, we determined that p21 transcription is governed by an incoherent feedforward loop mediated by MDM2. This network architecture facilitates rapid induction of p21 expression and variability in p21 transcription. Abrogating the feedforward loop overcomes rapid S-phase p21 degradation, with cells transitioning into a quiescent state that transcriptionally resembles a treatment-tolerant persister state. Our findings have important implications for therapeutic strategies based on activating p53.

Astaxanthin Induces Apoptosis in MCF-7 Cells through a p53-Dependent Pathway.

Astaxanthin (3,3'-dihydroxy-β,β-carotene-4,4'-dione; AXT) is a xanthophyll β-carotenoid found in microalgae, seafood, fungi, complex plants, flamingos, and quail. It is well known that AXT plays a role as a drug with antioxidant and antitumor properties. Furthermore, several studies have reported that the reagent shows anti-inflammatory and neuroprotective effects. Recently, it was found that AXT acts as a peroxisome proliferator-activated receptor γ (PPARγ) modulator. To investigate the effect of AXT on MCF-7 cells (a human breast cancer cell line), the cells were treated with various concentrations of AXT. The treatment induced the decrease in cell number in a dose-dependent manner. Additionally, the Annexin V-positive cells were increased by the AXT treatment. These results indicated that apoptosis was induced in the tumor cells through the treatment of AXT. To elucidate the connection between apoptosis and p53, the levels of p53 and p21 proteins were assessed. Consequently, it was observed that the expression of p53 and p21 increased proportionally to the concentration of the AXT treatment. These findings suggest that the apoptosis of MCF-7 cells induced by AXT operates through a p53-dependent pathway, implying that AXT could potentially have a beneficial role in future breast cancer treatments. Thus, our results will provide a direction for future cancer challenges.

Evaluation of IKK-β, NF-kβ, p53, and Ki-67 Protein and Gene Expression in Neuroblastoma Cells Treated with Cisplatin

Evaluation of IKK-β, NF-kβ, p53, and Ki-67 Protein and Gene Expression in Neuroblastoma Cells Treated with Cisplatin

Impacts of cytoplasmic p53 aggregates on the prognosis and the transcriptome in lung squamous cell carcinoma.

The tumor suppressor TP53 gene, the most frequently mutated gene in human cancers, produces the product tumor protein p53, which plays an essential role in DNA damage. p53 protein mutations may contribute to tumorigenesis by loss of tumor suppressive functions and malignancy of cancer cells via gain-of-oncogenic functions. We previously reported that mutant p53 proteins form aggregates and that cytoplasmic p53 aggregates were associated with poor prognosis in human ovarian cancer. However, the prognostic impact of p53 aggregation in other tumors including lung squamous cell carcinoma (SCC) is poorly understood. Here, we demonstrated that lung SCC cases with cytoplasmic p53 aggregates had a significantly poor clinical prognosis. Analysis via patient-derived tumor organoids (PDOs) established from lung SCC patients and possessing cytoplasmic p53 aggregates showed that eliminating cytoplasmic p53 aggregates suppressed cell proliferation. RNA sequencing and transcriptome analysis of p53 aggregate-harboring PDOs indicated multiple candidate pathways involved in p53 aggregate oncogenic functions. With lung SCC-derived cell lines, we found that cytoplasmic p53 aggregates contributed to cisplatin resistance. This study thus shows that p53 aggregates are a predictor of poor prognosis in lung SCC and suggests that detecting p53 aggregates via p53 conventional immunohistochemical analysis may aid patient selection for platinum-based therapy.