Search Results (91)

The colonic epithelium renews rapidly and must balance proliferation with apoptosis to preserve barrier integrity. We investigated whether grape antioxidant dietary fiber (GADF), a grape pomace-derived dietary fiber matrix naturally rich in high molecular weight non-extractable polyphenols, modulates barrier integrity, through proliferation/cell cycle and apoptosis. To gain mechanistic insight, we examined the role of heat-shock proteins (Hsps), and AMP-activated protein kinase (AMPK)–mTOR–lipid-metabolism signaling in healthy proximal colon. Male Wistar rats received either a cellulose-based control diet or an isoenergetic diet where cellulose was replaced with 5% GADF for four weeks. Morphometric analysis, immunohistochemistry, Western blotting, TUNEL, and caspase activity assays quantified cell cycle, apoptotic, Hsps, and metabolic pathways. GADF strengthened the epithelial barrier, increasing goblet cells, occludin, and ZO-1, while reducing crypt depth. Proliferation was suppressed, as indicated by reduced PCNA, cyclins E and D1, and higher p-p53^Ser392, p21^Cip1/Waf1, and p27^Kip1 levels, consistent with G1 arrest. Apoptosis was attenuated, with increased mitochondrial Bcl-2/Bax and Bcl-xL/Bax ratios, lower cytosolic cytochrome c and apoptosis-inducing factor (AIF), and reduced caspase-9 and caspase-3 activities. Hsp27, but not Hsp70, was selectively induced. GADF activated AMPK and p-Raptor, enhanced ACC1 phosphorylation and CPT1, and supported a shift toward fatty acid β-oxidation. Correlation analysis revealed a strong association between Hsp27 and p-p53^Ser392, suggesting potential links between barrier proteins and metabolic pathways. In conclusion, GADF preserves barrier integrity and redirects metabolism via AMPK–Hsp27 signaling, thereby promoting colonic homeostasis. These findings highlight grape pomace as a sustainable source of functional ingredients for nutritional strategies to reinforce epithelial defenses and reduce disease risk. Full article

Background/Objective: Cellular senescence is increasingly recognized as a key mechanism underlying sarcopenia, an age-related muscle disorder with no effective therapeutic. 6,4′-Dihydroxy-7-methoxyflavanone (DMF), a flavonoid isolated from Dalbergia odorifera T. Chen, has shown anti-senescence potential. This study aimed to investigate the protective effects of DMF against myoblasts senescence and elucidate the underlying molecular mechanisms. Method: A cellular model of senescence was established in C2C12 myoblasts using D-galactose (D-gal). The effects of DMF pretreatment were evaluated by assessing senescence phenotypes, myogenic differentiation, and mitochondrial function. The role of Sirtuin3 (SIRT3) was confirmed using siRNA-mediated knockdown. Results: DMF Pre-treatment effectively attenuated D-gal-induced senescence, as indicated by restored proliferation, reduced senescence-associated β-galactosidase activity, decreased DNA damage, and the downregulation of p53, p21^Cip1/WAF1 and p16^INK4a. Furthermore, DMF rescued myogenic differentiation capacity, enhancing the expression of Myoblast determination protein 1, Myogenin, Myosin heavy chain and Muscle-specific regulatory factor 4, and promoting myotube formation. Mechanistically, DMF was identified as a SIRT3 activator. It enhanced SIRT3 expression and activity, leading to the deacetylation and activation of the mitochondrial antioxidant enzyme superoxide dismutase 2. This consequently reduced mitochondrial reactive oxygen species, improved mitochondrial membrane potential and ATP production, and suppressed the NF-κB pathway by inhibiting IκBα phosphorylation and p65 acetylation/nuclear translocation. Crucially, all the beneficial effects of DMF—including oxidative stress reduction, mitochondrial functional recovery, anti-inflammatory action, and ultimately, the attenuation of senescence and improvement of myogenesis—were abolished upon SIRT3 knockdown. Conclusions: Our findings demonstrate that DMF alleviates myoblasts senescence and promotes myogenic differentiation by activating the SIRT3-SOD2 pathway, thereby reducing oxidative stress and NF-κB-driven inflammation responses. DMF emerges as a promising therapeutic candidate for sarcopenia. Full article

Background/Objectives: The effects of PD-L1 are mediated via its binding to the PD-1 receptor, which mediates the signals intracellularly to suppress T-cell responses. The expression levels of PD-L1 on cancer cells are an important indicator of immunosuppression and cause poor prognosis in several types of cancers. Therefore, the identification and characterization of mechanisms that regulate the expression of PD-L1 in cancer patients is very critical. Method: Our experiment was designed to determine the impact of histone deacetylase (HDAC) inhibitor on PD-L1 expression to reverse tumor-induced immunosuppression using H460 and HCC827 lung cancer cell lines. These cells were treated with the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). PD-L1 expression levels were assessed along with key regulatory proteins, including p53, p21, acetyl-histones, DNMT3B, MGMT, and trimethyl histones. Results: In our experiments, suberoylanilide hydroxamic acid (SAHA) was able to reduce the expression of PD-L1 by 60% in a dose-dependent manner. While the level of PD-L1 was significantly reduced, a concurrent increase in levels of p53, p21, and acetyl histone levels were observed in H460 and HCC827 cells following SAHA treatment. Furthermore, SAHA treatment was able to decrease the levels of DNMT3B, MGMT, and tri-methyl histones. It appears that the decrease in PD-L1 expression observed is solely because of p53 or p21WAF1/CIP1-mediated negative control on the transcription process. Conclusion: Our results suggest that SAHA can be used along with immune checkpoint inhibitors to potentiate the therapeutic outcomes in patients with excessive immunosuppression due to PD-L1 expression. Full article

Despite the availability of excellent HPV-specific vaccines, HPV-related conditions and, notably, their related neoplastic diseases are expected to impact human health for many years to come. Polyphenols and flavonoids are a large class of natural products, credited with a wide range of pharmacological properties including antineoplastic activity. However, the currently available data depict a rather heterogeneous and sometimes contradictory landscape, and no univocal conclusions can be drawn. To shed light on such a controversial issue, a restricted list of promising polyphenols were evaluated for their antineoplastic activity on HPV-transformed cells. Among them, Kaempferol, Galangin, and Luteolin proved to have distinct anti-clonal activity with ID₅₀ values, respectively, of 1.25, 6.25, and 3.0 microMolar, and three other compounds, namely, Chrysin, Quercetin, and Apigenin, showed fair although less intense activity with ID values, respectively, of 25.0, 40, and 25 microMolar. Interestingly, a distinct anti-proliferative effect could also be suggested for Kaempferol, Luteolin, and Apigenine. Cooperative anti-clonal effects could be suggested for binary and ternary compositions made of Kaepferol, Galangin, and Luteolin once combined at concentrations ranging from 2 to 8 microMolar. At these concentrations, the single components and the triple combination induced distinct cell cycle modulation associated with marked restoration of the p53 and p21Cip1/Waf1 levels, consistent with the disruption of the E6/E6AP interaction whose continuous activity is necessary for both the induction and maintenance of the viral-induced neoplastic phenotype. Full article

To identify the differences between aged and young human hematopoiesis, we performed a direct comparison of aged and young human hematopoietic stem and progenitor cells (HSPCs). Alterations in transcriptome profiles upon aging between humans and mice were then compared. Human specimens consist of CD34+ cells from bone marrow, and mouse specimens of hematopoietic stem cells (HSCs; Lin− Kit+ Sca1+ CD150+). Single-cell transcriptomic studies, functional clustering, and developmental trajectory analyses were performed. A significant increase in multipotent progenitor 2A (MPP2A) cluster is found in the early HSC trajectory in old human subjects. This cluster is enriched in senescence signatures (increased telomere attrition, DNA damage, activation of P53 pathway). In mouse models, the accumulation of an analogous subset was confirmed in the aged LT-HSC population. Elimination of this subset has been shown to rejuvenate hematopoiesis in mice. A significant activation of the P53–P21WAF1/CIP1 pathway was found in the MPP2A population in humans. In contrast, the senescent HSCs in mice are characterized by activation of the p16Ink4a pathway. Aging in the human HSC compartment is mainly caused by the clonal evolution and accumulation of a senescent cell cluster. A population with a similar senescence signature in the aged LT-HSCs was confirmed in the murine aging model. Clearance of this senescent population with senotherapy in humans is feasible and potentially beneficial. Full article

Background: Pancreatic Ductal Adeno-Carcinoma (PDAC) is a highly aggressive cancer, with limited treatment options. Disruption of the circadian clock, which regulates key cellular processes, has been implicated in PDAC initiation and progression. Hence, targeting circadian clock components may offer new therapeutic opportunities for the disease. This study investigates the cytopathic effects of TH301, a novel CRY2 stabilizer, on PDAC cells, aiming to evaluate its potential as a novel therapeutic agent. Methods: PDAC cell lines (AsPC-1, BxPC-3 and PANC-1) were treated with TH301, and cell viability, cell cycle progression, apoptosis, autophagy, circadian gene, and protein expression profiles were analyzed, using MTT assay, flow cytometry, Western blotting, and RT-qPCR technologies. Results: TH301 proved to significantly decrease cell viability and to induce cell cycle arrest at the G1-phase across all PDAC cell lines herein examined, especially the AsPC-1 and BxPC-3 ones. It caused dose-dependent apoptosis and autophagy, and it synergized with Chloroquine and Oxaliplatin to enhance anti-oncogenicity. The remarkable induction of p21 by TH301 was shown to follow clock- and p53-independent patterns, thereby indicating the critical engagement of alternative mechanisms. Conclusions: TH301 demonstrates significant anti-cancer activities in PDAC cells, thus serving as a promising new therapeutic agent, which can also synergize with approved treatment schemes by targeting pathways beyond circadian clock regulation. Altogether, TH301 likely opens new therapeutic windows for the successful management of pancreatic cancer in clinical practice. Full article

An abdominal aortic aneurysm (AAA) is described as a gradual and localized permanent expansion of the aorta resulting from the weakening of the vascular wall. The key aspects of AAA’s progression are high proteolysis of the structural elements of the vascular wall, the depletion of vascular smooth muscle cells (VSMCs), and a chronic immunoinflammatory response. The pathological mechanisms underpinning the development of an AAA are complex and still unknown. At present, there are no successful drug treatments available that can slow the progression of an AAA or prevent the rupture of the aneurysmal vascular wall. Recently, it has been suggested that endothelial cellular senescence may be involved in vascular aging and vascular aging diseases, but there is no clear correlation between cellular senescence and AAAs. Therefore, the aim of this study was to identify the presence of senescent cells on the vascular wall of aneurysmatic abdominal aortas and to correlate their distribution with the morphological markers of AAAs. Pathological and healthy segments of abdominal aortas were collected during repair surgery and immediately processed for histological and immunohistochemical analyses. Hematoxylin/eosin, Verhoeff–van Gieson, and Goldner’s Masson trichrome staining procedures were carried out to investigate the morphological features related to the pathology. Immunohistochemical investigations for the p21^cip1/waf1, p53, and NFkB markers were carried out to selectively identify positive cells in the vascular wall of the AAA samples related to cellular senescence and an inflammatory microenvironment. The results revealed the presence of a few senescent vascular cells on the aneurysmatic wall of the abdominal aortas, surrounded by a highly inflamed microenvironment that was highly expressed in the tunica media and adventitia of both pathological and healthy segments. Our data demonstrate the presence of senescent vascular cells in AAA samples, which could enhance the promotion of a high inflammatory vascular microenvironment, supporting the evolution of the pathology. Although this study was based on only two cases, the results highlight the importance of targeting cellular senescence to reduce an inflammatory microenvironment, which can support the progression of age-related diseases. Full article

Background/Objectives: The ribosomal S6 kinase 2 (S6K2) acts downstream of the mechanistic target of rapamycin complex 1 and is a homolog of S6K1 but little is known about its downstream effectors. The objective of this study was to use an unbiased transcriptome profiling to uncover how S6K2 promotes breast cancer cell survival. Methods: RNA-Seq analysis was performed to identify novel S6K2 targets. Cells were transfected with siRNAs or plasmids containing genes of interest. Western blot analyses were performed to quantify total and phosphorylated proteins. Apoptosis was monitored by treating cells with different concentrations of doxorubicin. Results: Silencing of S6K2, but not S6K1, decreased p21 in MCF-7 and T47D breast cancer cells. Knockdown of Akt1 but not Akt2 decreased p21 in MCF-7 cells whereas both Akt1 and Akt2 knockdown attenuated p21 in T47D cells. While Akt1 overexpression enhanced p21 and partially reversed the effect of S6K2 deficiency on p21 downregulation in MCF-7 cells, it had little effect in T47D cells. S6K2 knockdown increased JUN mRNA and knockdown of cJun enhanced p21. Low concentrations of doxorubicin increased, and high concentrations decreased p21 levels in T47D cells. Silencing of S6K2 or p21 sensitized T47D cells to doxorubicin via c-Jun N-terminal kinase (JNK)-mediated downregulation of Mcl-1. Conclusions: S6K2 knockdown enhanced doxorubicin-induced apoptosis by downregulating the cell cycle inhibitor p21 and the anti-apoptotic protein Mcl-1 via Akt and/or JNK. Full article

p57^Kip2 is a member of the cyclin-dependent kinase (CDK) Interacting Protein/Kinase Inhibitory Protein (CIP/Kip) family that also includes p21^Cip1/WAF1 and p27^Kip1. Different from its siblings, few data are available about the p57^Kip2 protein, especially in humans. Structurally, p57^Kip2 is an intrinsically unstructured protein, a characteristic that confers functional flexibility with multiple transient interactions influencing the metabolism and roles of the protein. Being an IUP, its localization, stability, and binding to functional partners might be strongly modulated by post-translational modifications, especially phosphorylation. In this work, we investigated by two-dimensional analysis the phosphorylation pattern of p57^Kip2 in different cellular models, revealing how the human protein appears to be extensively phosphorylated, compared to p21^Cip1/WAF1 and p27^Kip1. We further observed clear differences in the phosphoisoforms distributed in the cytosolic and nuclear compartments in asynchronous and synchronized cells. Particularly, the unmodified form is detectable only in the nucleus, while the more acidic forms are present in the cytoplasm. Most importantly, we found that the phosphorylation state of p57^Kip2 influences the binding with some p57^Kip2 partners, such as CDKs, LIMK1 and CRM1. Thus, it is necessary to completely identify the phosphorylated residues of the protein to fully unravel the roles of this CIP/Kip protein, which are still partially identified. Full article

A group of intrinsically disordered proteins (IDPs) are subject to 20S proteasomal degradation in a ubiquitin-independent manner. Recently, we have reported that many IDPs/IDRs are targeted to the 20S proteasome via interaction with the C-terminus of the PSMA3 subunit, termed the PSMA3 Trapper. In this study, we investigated the biological significance of the IDP–Trapper interaction using the IDP p21. Using a split luciferase reporter assay and conducting detailed p21 mutagenesis, we first identified the p21 RRLIF box, localized at the C-terminus, as mediating the Trapper interaction in cells. To demonstrate the role of this box in p21 degradation, we edited the genome of HEK293 and HeLa cell lines using a CRISPR strategy. We found that the p21 half-life increased in cells with either a deleted or mutated p21 RRLIF box. The edited cell lines displayed an aberrant cell cycle pattern under normal conditions and in response to DNA damage. Remarkably, these cells highly expressed senescence hallmark genes in response to DNA damage, highlighting that the increased p21 half-life, not its actual level, regulates senescence. Our findings suggest that the p21 RRLIF box, which mediates interactions with the PSMA3 Trapper, acts as a ubiquitin-independent degron. This degron is positioned adjacent to the previously identified ubiquitin-dependent degron, forming a dual degron module that functionally regulates p21 degradation and its physiological outcomes. Full article

Background and Objectives: The presence and contribution of senescent cells in premalignant lesions is well documented, but not in germ cell neoplasia in situ. The purpose of this study is to identify the presence of senescent cells in pre-malignant testicular conditions and in different histological types of testicular cancer. Materials and Methods: Thirty patients who underwent orchiectomy due to testicular tumors were included. Formalin-fixed paraffin-embedded (FFPE) testicular tissue for each patient was available. Sections from these specimens were examined by immunohistochemical analysis with the following markers: GL13 for cellular senescence, p21^WAF1/Cip1 for cell cycle arrest, and Ki67 for cell proliferation. Results: Thirteen (43.3%) suffered from seminoma with a mean total proportion of GCNIS senescence of 20.81 ± 6.81%. In the group of embryonal testicular tumors, nine (30%) patients were included, with an average rate of 6.64 ± 5.42% of senescent cells in GCNIS. One (3.3%) patient suffered from chondrosarcoma in which 7.9% of GL13+ cells were detected in GCNIS. Four (13.4%) patients suffered from teratoma and three (10%) from yolk sac tumors, while GCNIS senescence was detected in a range of 4.43 ± 1.78% and 3.76 ± 1.37%, respectively. Conclusions: Cellular senescence was detected in both germ cell neoplasia in situ and testicular cancer, but was more prevalent within the premalignant lesions. Full article

Cyclic pentapeptide compounds have garnered much attention as a drug discovery resource. This study focused on the characterization and anti-benign prostatic hyperplasia (BPH) properties of avellanin A from Aspergillus fumigatus fungus in marine sediment samples collected in the Beibu Gulf of Guangxi Province in China. The antiproliferative effect and molecular mechanism of avellanin A were explored in testosterone propionate (TP)-induced RWPE-1 cells. The transcriptome results showed that avellanin A significantly blocked the ECM–receptor interaction and suppressed the downstream PI3K-Akt signalling pathway. Molecular docking revealed that avellanin A has a good affinity for the cathepsin L protein, which is involved in the terminal degradation of extracellular matrix components. Subsequently, qRT-PCR analysis revealed that the expression of the genes COL1A1, COL1A2, COL5A2, COL6A3, MMP2, MMP9, ITGA2, and ITGB3 was significantly downregulated after avellanin A intervention. The Western blot results also confirmed that it not only reduced ITGB3 and FAK/p-FAK protein expression but also inhibited PI3K/p-PI3K and Akt/p-Akt protein expression in the PI3K-Akt signalling pathway. Furthermore, avellanin A downregulated Cyclin D1 protein expression and upregulated Bax, p21^WAF1/Cip1, and p53 proapoptotic protein expression in TP-induced RWPE-1 cells, leading to cell cycle arrest and inhibition of cell proliferation. The results of this study support the use of avellanin A as a potential new drug for the treatment of BPH. Full article

I propose a new strategy to suppress human cancer completely with two entirely new drug compounds exploiting cancer’s Warburg effect characterized by a defective mitochondrial aerobic respiration, substituted by cytosolic aerobic fermentation/glycolysis of D-(+)-glucose into L-(+)-lactic acid. The two essentially new drugs, compound 1 [P(op)T(est)162] and compound 3 (PT167), represent new highly symmetric, four-bladed propeller-shaped polyammonium cations. The in vitro antineoplastic highly efficacious drug compound 3 represents a covalent combination of compound 1 and compound 2 (PT166). The intermediate drug compound 2 is an entirely new colchic(in)oid derivative synthesized from colchicine. Compound 2’s structure was determined using X-ray crystallography. Compound 1 and compound 3 were active in vitro versus 60 human cancer cell lines of the National Cancer Institute (NCI) Developmental Therapeutics Program (DTP) 60-cancer cell testing. Compound 1 and compound 3 not only stop the growth of cancer cells to ±0% (cancerostatic effect) but completely kill nearly all 60 cancer cells to a level of almost −100% (tumoricidal effect). Compound 1 and compound 3 induce mitochondrial apoptosis (under cytochrome c release) in all cancer cells tested by (re)activating (in most cancers impaired) p53 function, which results in a decrease in cancer’s dysregulated cyclin D1 and an induction of the cell cycle-halting cyclin-dependent kinase inhibitor p21^Waf1/p21^Cip1. Full article

Orthodontic tooth movement (OTM) is thought to be impeded by bisphosphonate (BP) therapy, mainly due to increased osteoclast apoptosis and changes in the periodontal ligament (PdL), a connecting tissue between the alveolar bone and teeth. PdL cells, mainly fibroblasts (PdLFs), are crucial regulators in OTM by modulating force-induced local inflammatory processes. Recently, we identified the TGF-β/BMP superfamily member GDF15 as an important modulator in OTM, promoting the pro-inflammatory mechanoresponses of PdLFs. The precise impact of the highly potent BP zoledronate (ZOL) on the mechanofunctionality of PdLFs is still under-investigated. Therefore, the aim of this study was to further characterize the ZOL-induced changes in the initial inflammatory mechanoresponse of human PdLFs (hPdLFs) and to further clarify a potential interrelationship with GDF15 signaling. Thus, two-day in vitro treatment with 0.5 µM, 5 µM and 50 µM of ZOL altered the cellular properties of hPdLFs partially in a concentration-dependent manner. In particular, exposure to ZOL decreased their metabolic activity, the proliferation rate, detected using Ki-67 immunofluorescent staining, and survival, analyzed using trypan blue. An increasing occurrence of DNA strand breaks was observed using TUNEL and an activated DNA damage response was demonstrated using H2A.X (phosphoS139) staining. While the osteogenic differentiation of hPdLFs was unaffected by ZOL, increased cellular senescence was observed using enhanced p21^{Waf1/Cip1/Sdi1} and β-galactosidase staining. In addition, cytokine-encoding genes such as IL6, IL8, COX2 and GDF15, which are associated with a senescence-associated secretory phenotype, were up-regulated by ZOL. Subsequently, this change in the hPdLF phenotype promoted a hyperinflammatory response to applied compressive forces with an increased expression of the pro-inflammatory markers IL1β, IL6 and GDF15, as well as the activation of monocytic THP1 cells. GDF15 appeared to be particularly relevant to these changes, as siRNA-mediated down-regulation balanced these hyperinflammatory responses by reducing IL-1β and IL-6 expression (IL1B p-value < 0.0001; IL6 p-value < 0.001) and secretion (IL-1β p-value < 0.05; IL-6 p-value < 0.001), as well as immune cell activation (p-value < 0.0001). In addition, ZOL-related reduced RANKL/OPG values and inhibited osteoclast activation were enhanced in GDF15-deficient hPdLFs (both p-values < 0.0001; all statistical tests: one-way ANOVA, Tukey’s post hoc test). Thus, GDF15 may become a promising new target in the personalized orthodontic treatment of bisphosphonatepatients. Full article

Cyclin-dependent kinase inhibitor 1A (Cip1/Waf1/CDKN1A/p21) is a well-established protein, primarily recognised for its pivotal role in the cell cycle, where it induces cell cycle arrest by inhibiting the activity of cyclin-dependent kinases (CDKs). Over the years, extensive research has shed light on various additional mechanisms involving CDKN1A/p21, implicating it in processes such as apoptosis, DNA damage response (DDR), and the regulation of stem cell fate. Interestingly, p21 can function either as an oncogene or as a tumour suppressor in these contexts. Complicating matters further, the expression of CDKN1A/p21 is elevated in certain tumour types while downregulated in others. In this comprehensive review, we provide an overview of the multifaceted functions of CDKN1A/p21, present clinical data pertaining to cancer patients, and delve into potential strategies for targeting CDKN1A/p21 as a therapeutic approach to cancer. Manipulating CDKN1A/p21 shows great promise for therapy given its involvement in multiple cancer hallmarks, such as sustained cell proliferation, the renewal of cancer stem cells (CSCs), epithelial–mesenchymal transition (EMT), cell migration, and resistance to chemotherapy. Given the dual role of CDKN1A/p21 in these processes, a more in-depth understanding of its specific mechanisms of action and its regulatory network is imperative to establishing successful therapeutic interventions. Full article