Detection and quantification of γ-H2AX using a dissociation enhanced lanthanide fluorescence immunoassay

Controlled labelling of tracer antibodies for time-resolved fluorescence-based immunoassays

Tracer antibodies, which are labelled with fluorescent or other type of reporter molecules, are widely employed in diagnostic immunoassays. Time-resolved fluorescence immunoassay (TRFIA), recognized as one of the most sensitive immunoassay techniques, utilizes tracers labelled with lanthanide ion (Ln) chelates. The conventional approach for conjugating isothiocyanate (ITC) Ln-chelates to antibodies involves random chemical targeting of the primary amino group of Lys residues, requiring typically overnight exposure to an elevated pH of 9-9.3 and leading to heterogeneity. Moreover, efforts to enhance the sensitivity of the assays by introducing a higher number of Ln-chelates per tracer antibody are associated with an elevated risk of targeting critical amino acid residues in the binding site, compromising the binding properties of the antibody. Herein, we report a method to precisely label recombinant antibodies with a defined number of Ln-chelates in a well-controlled manner by employing the SpyTag/SpyCatcher protein ligation technology. We demonstrate the functionality of the method with a full-length recombinant antibody (IgG) as well as an antibody fragment by producing site-specifically labelled antibodies for TRFIA for cardiac troponin I (cTnI) detection with a significant improvement in assay sensitivity compared to that with conventionally labelled tracer antibodies. Overall, our data clearly illustrates the benefits of the site-specific labelling strategy for generating high-performing tracer antibodies for TRF immunoassays.

An Organ-on-Chip Platform for Simulating Drug Metabolism Along the Gut-Liver Axis

The human microbiome significantly influences drug metabolism through the gut-liver axis, leading to modified drug responses and potential toxicity. Due to the complex nature of the human gut environment, the understanding of microbiome-driven impacts on these processes is limited. To address this, a multiorgan-on-a-chip (MOoC) platform that combines the human microbial-crosstalk (HuMiX) gut-on-chip (GoC) and the Dynamic42 liver-on-chip (LoC), mimicking the bidirectional interconnection between the gut and liver known as the gut-liver axis, is introduced. This platform supports the viability and functionality of intestinal and liver cells. In a proof-of-concept study, the metabolism of irinotecan, a widely used colorectal cancer drug, is imitated within the MOoC. Utilizing liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), irinotecan metabolites are tracked, confirming the platform's ability to represent drug metabolism along the gut-liver axis. Further, using the authors' gut-liver platform, it is shown that the colorectal cancer-associated gut bacterium, Escherichia coli, modifies irinotecan metabolism through the transformation of its inactive metabolite SN-38G into its toxic metabolite SN-38. This platform serves as a robust tool for investigating the intricate interplay between gut microbes and pharmaceuticals, offering a representative alternative to animal models and providing novel drug development strategies.

Development of 225Ac-doped biocompatible nanoparticles for targeted alpha therapy

Targeted alpha therapy (TAT) relies on chemical affinity or active targeting using radioimmunoconjugates as strategies to deliver α-emitting radionuclides to cancerous tissue. These strategies can be affected by transmetalation of the parent radionuclide by competing ions in vivo and the bond-breaking recoil energy of decay daughters. The retention of α-emitting radionuclides and the dose delivered to cancer cells are influenced by these processes. Encapsulating α-emitting radionuclides within nanoparticles can help overcome many of these challenges. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles are a biodegradable and biocompatible delivery platform that has been used for drug delivery. In this study, PLGA nanoparticles are utilized for encapsulation and retention of actinium-225 ([225Ac]Ac3+). Encapsulation of [225Ac]Ac3+ within PLGA nanoparticles (Zave = 155.3 nm) was achieved by adapting a double-emulsion solvent evaporation method. The encapsulation efficiency was affected by both the solvent conditions and the chelation of [225Ac]Ac3+. Chelation of [225Ac]Ac3+ to a lipophilic 2,9-bis-lactam-1,10-phenanthroline ligand ([225Ac]AcBLPhen) significantly decreased its release (< 2%) and that of its decay daughters (< 50%) from PLGA nanoparticles. PLGA nanoparticles encapsulating [225Ac]AcBLPhen significantly increased the delivery of [225Ac]Ac3+ to murine (E0771) and human (MCF-7 and MDA-MB-231) breast cancer cells with a concomitant increase in cell death over free [225Ac]Ac3+ in solution. These results demonstrate that PLGA nanoparticles have potential as radionuclide delivery platforms for TAT to advance precision radiotherapy for cancer. In addition, this technology offers an alternative use for ligands with poor aqueous solubility, low stability, or low affinity, allowing them to be repurposed for TAT by encapsulation within PLGA nanoparticles.

Glutathione - IR 797 coupled Casein Nano-Trojan for augmenting the therapeutic efficacy of camptothecin in highly invasive triple negative breast cancer

The rapid metastasis & heterogenic constitution of triple negative breast cancer (TNBC) limits drug entry to the tumor, reducing treatment effectiveness. To address this, we have synthesized Casein nanoparticles (Cn NPs) with attached glutathione (GSH), a natural ligand for cancer cell overexpressed γ-glutamyl transpeptidase (GGT). Cn NPs encapsulated with Camptothecin and NIR dye IR 797 (CCN NPs) for combinatorial therapy of TNBC. The GSH-CCN nanoparticles (CCNG NPs) act as a Nano-Trojan to deceive the cancer cells by delivering therapeutic payloads directly to specific target cells. In this study, Casein Nano-Trojan is equipped with GSH as a targeting ligand for GGT. The binding of CCNG NPs with cell surface receptors switched the anionic charge to catanionic, prompting the target cell to engulf the nanoparticles. The Casein Nano-Trojan releases its therapeutic payload inside the target cell, potentially inhibiting proliferation & inducing a high percentage of cell death (85 ± 7 %). Disintegration of mitochondrial membrane potential, inhibition of both migration & re-growth were observed. Immunofluorescence, acridine orange/ethidium bromide stain, and nuclear fragmentation assay further confirmed the substantial DNA damage induced by the high expression of γH2AX and p53. Significant therapeutic efficacy was observed in the 3D spheroids of 4T1 cells and in vivo breast cancer mice model (BALB/c). These findings demonstrate that CCNG NPs could be an effective treatment approach for highly metastatic triple negative breast cancer.

RadPhysBio: A Radiobiological Database for the Prediction of Cell Survival upon Exposure to Ionizing Radiation

Based on the need for radiobiological databases, in this work, we mined experimental ionizing radiation data of human cells treated with X-rays, γ-rays, carbon ions, protons and α-particles, by manually searching the relevant literature in PubMed from 1980 until 2024. In order to calculate normal and tumor cell survival α and β coefficients of the linear quadratic (LQ) established model, as well as the initial values of the double-strand breaks (DSBs) in DNA, we used WebPlotDigitizer and Python programming language. We also produced complex DNA damage results through the fast Monte Carlo code MCDS in order to complete any missing data. The calculated α/β values are in good agreement with those valued reported in the literature, where α shows a relatively good association with linear energy transfer (LET), but not β. In general, a positive correlation between DSBs and LET was observed as far as the experimental values are concerned. Furthermore, we developed a biophysical prediction model by using machine learning, which showed a good performance for α, while it underscored LET as the most important feature for its prediction. In this study, we designed and developed the novel radiobiological 'RadPhysBio' database for the prediction of irradiated cell survival (α and β coefficients of the LQ model). The incorporation of machine learning and repair models increases the applicability of our results and the spectrum of potential users.

Different Impacts of DNA-PK and mTOR Kinase Inhibitors in Combination with Ionizing Radiation on HNSCC and Normal Tissue Cells

Despite substantial advancements in understanding the pathomechanisms of head and neck squamous cell carcinoma (HNSCC), effective therapy remains challenging. The application of kinase inhibitors (KIs) in HNSCC, specifically mTOR and DNA-PK inhibitors, can increase radiosensitivity and therefore presents a promising strategy when used simultaneously with ionizing radiation (IR) in cancer treatment. Our study focused on the selective DNA-PK-inhibitor AZD7648; the selective mTOR-inhibitor Sapanisertib; and CC-115, a dual inhibitor targeting both mTOR and DNA-PK. The impact of these KIs on HNSCC and normal tissue cells was assessed using various analytical methods including cell death studies, cell cycle analysis, real-time microscopy, colony-forming assays and immunohistochemical staining for γH2AX and downstream mTOR protein p-S6. We detected a strong inhibition of IR-induced DNA double-strand break (DSB) repair, particularly in AZD7648-treated HNSCC, whereas normal tissue cells repaired DNA DSB more efficiently. Additionally, AZD7648 + IR treatment showed a synergistic decline in cell proliferation and clonogenicity, along with an elevated G2/M arrest and cell death in the majority of HNSCC cell lines. CC-115 + IR treatment led to an elevation in G2/M arrest, increased cell death, and a synergistic reduction in cell proliferation, though the effect was notably lower compared to the AZD7648 + IR- treated group. Sapanisertib led to a high cellular toxicity in both HNSCC and normal tissue cells, even in non-irradiated cells. Regarding cell proliferation and the induction of apoptosis and necrosis, Sapanisertib + IR was beneficial only in HPV+ HNSCC. Overall, this study highlights the potential of AZD7648 as a radiosensitizing agent in advanced-stage HPV-positive and negative HNSCC, offering a promising therapeutic strategy. However, the dual mTOR/DNA-PK-I CC-115 did not provide a distinct advantage over the use of selective KIs in our investigations, suggesting limited benefits for its application in KI + IR therapy. Notably, the selective mTOR-inhibitor Sapanisertib was only beneficial in HPV+ HNSCC and should not be applied in HPV- cases.

Cocrystallization of Gefitinib Potentiate Single-Dose Oral Administration for Lung Tumor Eradication via Unbalancing the DNA Damage/Repair

Gefitinib (GEF) is a clinical medication for the treatment of lung cancer targeting the epidermal growth factor receptor (EGFR). However, its efficacy is remarkably limited by low solubility and dissolution rates. In this study, two cocrystals of GEF with co-formers were successfully synthesized using the recrystallization method characterized via Powder X-ray Diffraction, Fourier Transform Infrared Spectroscopy, and 2D Nuclear Overhauser Effect Spectroscopy. The solubility and dissolution rates of cocrystals were found to be two times higher than those of free GEF. In vitro cytotoxicity studies revealed that the cocrystals enhanced the inhibition of cell proliferation and apoptosis in A549 and H1299 cells compared to free GEF. In mouse models, GEF@TSBO demonstrated targeted, safe, and effective antitumor activity with only one-dose administration. Mechanistically, the GEF cocrystals were shown to increase the cellular levels of damaged DNA, while potentially downregulating PARP, thereby impairing the DNA repair machinery and leading to an imbalance between DNA damage and restoration. These findings suggest that the cocrystallization of GEF could serve as a promising adjunct to significantly enhance the physicochemical and biopharmaceutical performance for lung cancer treatment, providing a facial strategy to improve GEF anticancer efficiency with high bioavailability that can be orally administrated with only one dose.

Current and future directions of USP7 interactome in cancer study

The ubiquitin-proteasome system (UPS) is an essential protein quality controller for regulating protein homeostasis and autophagy. Ubiquitination is a protein modification process that involves the binding of one or more ubiquitins to substrates through a series of enzymatic processes. These include ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin ligases (E3). Conversely, deubiquitination is a reverse process that removes ubiquitin from substrates via deubiquitinating enzymes (DUBs). Dysregulation of ubiquitination-related enzymes can lead to various human diseases, including cancer, through the modulation of protein ubiquitination. The most structurally and functionally studied DUB is the ubiquitin-specific protease 7 (USP7). Both the TRAF and UBL domains of USP7 are known to bind to the [P/A/E]-X-X-S or K-X-X-X-K motif of substrates. USP7 has been shown to be involved in cancer pathogenesis by binding with numerous substrates. Recently, a novel substrate of USP7 was discovered through a systemic analysis of its binding motif. This review summarizes the currently discovered substrates and cellular functions of USP7 in cancer and suggests putative substrates of USP7 through a comprehensive systemic analysis.

Trinuclear rhenium(I)-based metallocages as anticancer agents towards human cervical cancer cells

The first examples of spherical-shaped trinuclear rhenium(I) organometallic cages displaying cytotoxic, antimetastatic, antiproliferative and DNA-damaging behavior towards a human cervical (HeLa) cancer cell line are reported. The compact design of the metallocages facilitates their interactions with biosystems leading to comparable efficiency to that of the commonly used anticancer drug cisplatin.

Protective Effects of Piceatannol on DNA Damage in Benzo[a]pyrene-Induced Human Colon Epithelial Cells

Evidence shows that the dietary intake of polycyclic aromatic hydrocarbons (PAHs) from food processing induces the cellular DNA damage response and leads to the development of colorectal cancer (CRC). Therefore, protecting from cellular DNA damage might be an effective strategy in preventing CRC. Benzo[a]pyrene (B[a]P) was used as a CRC initiator in the present study. Compared with other stilbenoids, piceatannol (PIC) showed the most effective inhibition of B[a]P-induced cytochrome P450 1B1 (CYP1B1) protein expression in NCM460 normal human colon epithelial cells. PIC treatment alleviated DNA migration and enhanced the expression of DNA-repair-related proteins, including histone 2AX (H2AX), checkpoint kinase 1 (Chk1), and p53, in B[a]P-induced NCM460 cells. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA) revealed that PIC exerted antioxidative effects on NCM460 cells by increasing the glutathione (GSH) content and scavenging the excess intracellular reactive oxygen species (ROS) induced by B[a]P. Furthermore, PIC suppressed B[a]P-induced CYP1B1 protein expression and stimulated miR-27b-3p expression. The upregulation of phase II detoxification enzymes, such as nicotinamide adenine dinucleotide phosphate (NADPH) and quinone oxidoreductase 1 (NQO1), and the antioxidative enzyme, heme oxygenase 1 (HO-1), via the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was observed in the PIC-treated group. Our results suggest that PIC is a potential CRC-blocking agent due to its ability to alleviate DNA damage, decrease intracellular ROS production, modulate the metabolism and detoxification of B[a]P, and activate the Nrf2 signaling pathway in B[a]P-induced NCM460 cells.

Immune checkpoint inhibitors modulate the cytotoxic effect of chemotherapy in lung adenocarcinoma cells

Immunotherapy using immune checkpoint inhibitors (ICIs) has significantly improved survival in patients with non-small cell lung cancer (NSCLC), and ICIs are increasingly used in combination with cytotoxic treatments, such as chemotherapy. Although combined treatments are more effective, not all patients respond to the therapy; therefore, a detailed understanding of the effect of treatment combinations at the tumour level is needed. The present study aimed to explore whether ICIs could affect the cytotoxic effects of chemotherapy on lung adenocarcinoma cell lines with different PD-L1 expression levels (high, HCC-44; low, A-549). Using the resazurin-based assay, the efficacy of seven chemotherapeutic agents (cisplatin, etoposide, gemcitabine, pemetrexed, vinorelbine, docetaxel and paclitaxel) was compared in the presence or absence of the individually chosen single doses of four ICIs (nivolumab, pembrolizumab, atezolizumab and durvalumab). The results revealed that different ICIs can exhibit either potentiating or depotentiating effects, depending on the chemotherapy agent or lung adenocarcinoma cell line used. Durvalumab was the most promising ICI, which potentiated most chemotherapy agents in both cell lines, especially in the case of high PD-L1 expression. By contrast, nivolumab, exhibited depotentiating trends in several combinations. The immunostaining of γH2AX in treated cells confirmed that the potentiation of the chemotherapeutic cytotoxicity by durvalumab was at least partially mediated via increased DNA damage; however, this effect was strongly dependent on the chemotherapy agent and cell line used. Our future studies aim to address the specific mechanisms underlying the observed ICI-induced potentiation or depotentiation.

3D printable acrylate polydimethylsiloxane resins for cell culture and drug testing

Nowadays, most of the microfluidic devices for biological applications are fabricated with only few well-established materials. Among these, polydimethylsiloxane (PDMS) is the most used and known. However, it has many limitations, like the operator dependent and time-consuming manufacturing technique and the high molecule retention. TEGORad or Acrylate PDMS is an acrylate polydimethylsiloxane copolymer that can be 3D printed through Digital Light Processing (DLP), a technology that can boast reduction of waste products and the possibility of low cost and rapid manufacturing of complex components. Here, we developed 3D printed Acrylate PDMS-based devices for cell culture and drug testing. Our in vitro study shows that Acrylate PDMS can sustain cell growth of lung and skin epithelium, both of great interest for in vitro drug testing, without causing any genotoxic effect. Moreover, flow experiments with a drug-like solution (Rhodamine 6G) show that Acrylate PDMS drug retention is negligible unlike the high signal shown by PDMS. In conclusion, the study demonstrates that this acrylate resin can be an excellent alternative to PDMS to design stretchable platforms for cell culture and drug testing.

Camptothecin loaded casein nanosystem for tuning the therapeutic efficacy against highly metastatic triple-negative breast cancer cells

The heterogenic of TNBC and the side effects of chemo drugs lead to the failure of therapy. Protein-based nanoplatforms have emerged as an important domain in protein-engineered biomedicine for delivering anticancer therapeutics. Protein-based nanosystems are biocompatible and biodegradable, with a long half-life and high purity. TNBC is sensitive to DNA-damaging chemo drugs. In this study, we used 10-hydroxy camptothecin, which causes DNA damage in cancer cells. However, the inappropriate solubility and toxic side effects limit its application in cancer therapy. We encapsulated 10-Hydroxycamptothecin in biocompatible casein by synthesizing nanoparticles from it. The synthesized CS and CCS NPs showed excellent biocompatibility in fibroblast cell lines L929, NIH-3T3, and zebrafish embryos. Enhanced uptake of CCS NPs in zebrafish embryos and 4T1 cells, cancer cell toxicity of nearly 80-85%, sub-cellular mitochondrial localization, alterations of mitochondrial membrane potential, lysosomal localization, and reactive oxygen species generation that causes cancer cell apoptosis have been observed. Growth inhibition of 4T1 cell colonies and antimetastatic activity were also noted. Further upregulation of γ-H2AX which causes DNA damage, downregulation of the PARP protein related to DNA repair, and increased level of the CHOP protein marker for endoplasmic reticulum stress-mediated cell death were observed. The 3-D model of 4T1 cells exhibited deep tumor penetration with significant therapeutic efficacy for CCS NPs. These results imply that casein-based nanoformulation could open a new scope for safe and affordable cancer therapy in TNBC.

Confinement of Triple-Enzyme-Involved Antioxidant Cascade in Two-Dimensional Nanostructure

Application of antioxidant enzymes in medical or industrial processes is limited due to their high sensitivity to environmental conditions. Incorporation of such enzymes in nanostructures provides a promising route to obtain highly efficient and robust biocatalytic system to scavenge reactive oxygen species (ROS). Here, this question was addressed by confinement of superoxide dismutase (SOD), horseradish peroxidase (HRP), and catalase (CAT) enzymes into nanostructures containing polyelectrolyte building blocks (alginate (Alg) and trimethyl chitosan (TMC)) and delaminated layered double hydroxide (dLDH) nanoparticle support. The nanocomposite possessed excellent structural and colloidal stability, while antioxidant tests revealed that the enzymes remained active upon immobilization and the developed composite greatly reduced intracellular oxidative stress in two-dimensional cell cultures. Moreover, it effectively prevented hydrogen peroxide-induced double stranded DNA breaks, which is a common consequence of oxidative stress. The results provide important tools to design complex nanostructures with multienzymatic antioxidant activities for ROS scavenging.

Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine Sulfonamides as Novel Potential Anticancer Agents: Cytotoxic and Genotoxic Activities In Vitro

In this paper, we present for the first time the evaluation of cytotoxicity and genotoxicity of de novo synthesized pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides MM129, MM130, and MM131 in human tumor cell lines: HeLa, HCT 116, PC-3, and BxPC-3. Cytotoxic and genotoxic properties of the tested compounds were estimated using the MTT assay, comet assay (alkaline and neutral version), and γ-H2AX immuno-staining. Examined sulfonamides exhibited strong anticancer properties towards tested cells in a very low concentration range (IC₅₀ = 0.17-1.15 μM) after 72 h exposure time. The results of the alkaline and neutral version of the comet assay following 24 h incubation of the cells with tested compounds demonstrated the capability of heterocycles to induce significant DNA damage in exposed cells. HCT 116 cells were the most sensitive to the genotoxic activity of novel tricyclic pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides in the neutral version of the comet assay. Immunocytochemical detection of γ-H2AX showed an increase in DNA DSBs level in the HCT 116 cell line, after 24 h incubation with all tested compounds, confirming the results obtained in the neutral comet assay. Among all investigated compounds, MM131 showed the strongest cytotoxic and genotoxic activity toward all tested cell types. In conclusion, our results suggest that MM129, MM130, and MM131 exhibit high cytotoxic and genotoxic potential in vitro, especially towards the colorectal cancer cell line HCT 116. However, further investigations and analyses are required for their future implementation in the field of medicine.

S-allylcysteine Ameliorates Aging Features Via Regulating Mitochondrial Dynamics in Naturally Aged C57BL/6J Mice

SCOPE

S-allylcysteine (SAC) is the most abundant organosulfur molecule derived from aged garlic. We evaluated the effects of S-allylcysteine (SAC) on improving aging in naturally aged C57BL/6J male mice and mitochondrial dynamics in C. elegans and its underlying mechanisms.

METHODS AND RESULTS

When mice had attained reproductive senescence at 60 weeks of age, SAC was supplemented to 0.05% and 0.2% into their normal diet for 12 weeks The results showed that SAC could significantly improve the level of hepatic OPA1 mRNA, which is a key factor for mitochondrial fusion, and consequently elevated the mitochondrial biogenesis-related proteins SIRT1 and PGC-1α, thus ameliorating oxidative stress, such as MDA in the liver and 8-OHdG in urine. Among the biochemical markers of aging, SAC significantly reduced liver GLB1 and SA-βgal, which were induced by replicative senescence. The mitochondria with GFP-tagged transgenic strain SJ4103 C. elegans was incubated with 5 or 50 μM SAC, and SAC treated groups maintained the linear morphology of mitochondria.

CONCLUSION

SAC regulated mitochondrial dynamics and ameliorated aging to a significant degree. This study also confirmed that mitochondrial dynamics are a promising target for screening materials to combat aging and as a direction for anti-aging product development. This article is protected by copyright. All rights reserved.

G-quadruplexes Stabilization Upregulates CCN1 and Accelerates Aging in Cultured Cerebral Endothelial Cells

Senescence in the cerebral endothelium has been proposed as a mechanism that can drive dysfunction of the cerebral vasculature, which precedes vascular dementia. Cysteine-rich angiogenic inducer 61 (Cyr61/CCN1) is a matricellular protein secreted by cerebral endothelial cells (CEC). CCN1 induces senescence in fibroblasts. However, whether CCN1 contributes to senescence in CEC and how this is regulated requires further study. Aging has been associated with the formation of four-stranded Guanine-quadruplexes (G4s) in G-rich motifs of DNA and RNA. Stabilization of the G4 structures regulates transcription and translation either by upregulation or downregulation depending on the gene target. Previously, we showed that aged mice treated with a G4-stabilizing compound had enhanced senescence-associated (SA) phenotypes in their brains, and these mice exhibited enhanced cognitive deficits. A sequence in the 3'-UTR of the human CCN1 mRNA has the ability to fold into G4s in vitro. We hypothesize that G4 stabilization regulates CCN1 in cultured primary CEC and induces endothelial senescence. We used cerebral microvessel fractions and cultured primary CEC from young (4-months old, m/o) and aged (18-m/o) mice to determine CCN1 levels. SA phenotypes were determined by high-resolution fluorescence microscopy in cultured primary CEC, and we used Thioflavin T to recognize RNA-G4s for fluorescence spectra. We found that cultured CEC from aged mice exhibited enhanced levels of SA phenotypes, and higher levels of CCN1 and G4 stabilization. In cultured CEC, CCN1 induced SA phenotypes, such as SA β-galactosidase activity, and double-strand DNA damage. Furthermore, CCN1 levels were upregulated by a G4 ligand, and a G-rich motif in the 3'-UTR of the Ccn1 mRNA was folded into a G4. In conclusion, we demonstrate that CCN1 can induce senescence in cultured primary CEC, and we provide evidence that G4 stabilization is a novel mechanism regulating the SASP component CCN1.