RESUMO
Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Despite recent therapeutic advancements, resistance to 5-fluorouracil (5-FU) remains a major obstacle to the successful treatment of this disease. We have previously identified the ribosomal protein uL3 as a key player in the cell response to 5-FU, and loss of uL3 is associated with 5-FU chemoresistance. Natural products, like carotenoids, have shown the ability to enhance cancer cell response to drugs and may provide a safer choice to defeat chemoresistance in cancer. Transcriptome analysis of a cohort of 594 colorectal patients revealed a correlation between uL3 expression and both progression-free survival and response to treatment. RNA-Seq data from uL3-silenced CRC cells demonstrated that a low uL3 transcriptional state was associated with an increased expression of specific ATP-binding cassette (ABC) genes. Using two-dimensional (2D) and three-dimensional (3D) models of 5-FU-resistant CRC cells stably silenced for uL3, we investigated the effect of a novel therapeutic strategy by combining ß-carotene and 5-FU using nanoparticles (NPs) as a drug delivery system. Our results indicated that the combined treatment might overcome 5-FU chemoresistance, inducing cell cycle arrest in the G2/M phase and apoptosis. Furthermore, the combined treatment significantly reduced the expression levels of analyzed ABC genes. In conclusion, our findings suggest that ß-carotene combined with 5-FU may be a more effective therapeutic approach for treating CRC cells with low levels of uL3.
Assuntos
Neoplasias Colorretais , beta Caroteno , Humanos , beta Caroteno/farmacologia , beta Caroteno/metabolismo , beta Caroteno/uso terapêutico , Proteína Supressora de Tumor p53/genética , Resistencia a Medicamentos Antineoplásicos/genética , Linhagem Celular Tumoral , Fluoruracila/farmacologia , Fluoruracila/uso terapêutico , Apoptose , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Regulação Neoplásica da Expressão GênicaRESUMO
Remarkable advances have been made in cancer therapy; however, the high degree of cellular heterogeneity observed during cancer progression is the major driver in the development of resistant phenotypes upon treatment administration [...].
Assuntos
Neoplasias , Humanos , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Carcinogênese/genética , Transformação Celular NeoplásicaRESUMO
The thrombin binding aptamer (TBA) possesses promising antiproliferative properties. However, its development as an anticancer agent is drastically impaired by its concomitant anticoagulant activity. Therefore, suitable chemical modifications in the TBA sequence would be required in order to preserve its antiproliferative over anticoagulant activity. In this paper, we report structural investigations, based on circular dichroism (CD) and nuclear magnetic resonance spectroscopy (NMR), and biological evaluation of four pairs of enantiomeric heterochiral TBA analogues. The four TBA derivatives of the d-series are composed by d-residues except for one l-thymidine in the small TT loops, while their four enantiomers are composed by l-residues except for one d-thymidine in the same TT loop region. Apart from the left-handedness for the l-series TBA derivatives, CD and NMR measurements have shown that all TBA analogues are able to adopt the antiparallel, monomolecular, 'chair-like' G-quadruplex structure characteristic of the natural D-TBA. However, although all eight TBA derivatives are endowed with remarkable cytotoxic activities against colon and lung cancer cell lines, only TBA derivatives of the l-series show no anticoagulant activity and are considerably resistant in biological environments.
Assuntos
Aptâmeros de Nucleotídeos/genética , Quadruplex G , Ligação Proteica/genética , Trombina/genética , Anticoagulantes/química , Anticoagulantes/uso terapêutico , Dicroísmo Circular , Humanos , Espectroscopia de Ressonância Magnética , Estereoisomerismo , Timidina/genéticaRESUMO
In this paper, we study the T30923 antiproliferative potential and the contribution of its loop residues in six different human cancer cell lines by preparing five T30923 variants using the single residue replacement approach of loop thymidine with an abasic site mimic (S). G-rich oligonucleotides (GRO) show interesting anticancer properties because of their capability to adopt G-quadruplex structures (G4s), such as the G4 HIV-1 integrase inhibitor T30923. Considering the multi-targeted effects of G4-aptamers and the limited number of cancer cell lines tested, particularly for T30923, it should be important to find a suitable tumor line, in addition to considering that the effects also strictly depend on G4s. CD, NMR and non-denaturating polyacrylamide gel electrophoresis data clearly show that all modified ODNs closely resemble the dimeric structure of parallel G4s' parent aptamer, keeping the resistance in biological environments substantially unchanged, as shown by nuclease stability assay. The antiproliferative effects of T30923 and its variants are tried in vitro by MTT assays, showing interesting cytotoxic activity, depending on time and dose, for all G4s, especially in MDA-MB-231 cells with a reduction in cell viability approximately up to 30%. Among all derivatives, QS12 results are the most promising, showing more pronounced cytotoxic effects both in MDA-MB-231 and Hela cells, with a decrease in cell viability from 70% to 60%. In summary, the single loop residue S substitution approach may be useful for designing antiproliferative G4s, considering that most of them, characterized by single residue loops, may be able to bind different targets in several cancer cell pathways. Generally, this approach could be of benefit by revealing some minimal functional structures, stimulating further studies aimed at the development of novel anticancer drugs.
Assuntos
Antineoplásicos , Aptâmeros de Nucleotídeos , Quadruplex G , Inibidores de Integrase de HIV , Neoplasias , Antineoplásicos/química , Aptâmeros de Nucleotídeos/química , Inibidores de Integrase de HIV/farmacologia , Células HeLa , Humanos , Neoplasias/tratamento farmacológico , TimidinaRESUMO
Cytosolic ribosomes (cytoribosomes) are macromolecular ribonucleoprotein complexes that are assembled from ribosomal RNA and ribosomal proteins, which are essential for protein biosynthesis. Mitochondrial ribosomes (mitoribosomes) perform translation of the proteins essential for the oxidative phosphorylation system. The biogenesis of cytoribosomes and mitoribosomes includes ribosomal RNA processing, modification and binding to ribosomal proteins and is assisted by numerous biogenesis factors. This is a major energy-consuming process in the cell and, therefore, is highly coordinated and sensitive to several cellular stressors. In mitochondria, the regulation of mitoribosome biogenesis is essential for cellular respiration, a process linked to cell growth and proliferation. This review briefly overviews the key stages of cytosolic and mitochondrial ribosome biogenesis; summarizes the main steps of ribosome biogenesis alterations occurring during tumorigenesis, highlighting the changes in the expression level of cytosolic ribosomal proteins (CRPs) and mitochondrial ribosomal proteins (MRPs) in different types of tumors; focuses on the currently available information regarding the extra-ribosomal functions of CRPs and MRPs correlated to cancer; and discusses the role of CRPs and MRPs as biomarkers and/or molecular targets in cancer treatment.
Assuntos
Transformação Celular Neoplásica , Neoplasias/metabolismo , Biogênese de Organelas , Ribossomos , Animais , Apoptose , Autofagia , Ciclo Celular , Movimento Celular , Nucléolo Celular/metabolismo , Citosol/metabolismo , Reparo do DNA , Estresse do Retículo Endoplasmático , Células Eucarióticas/metabolismo , Células Eucarióticas/ultraestrutura , Regulação Neoplásica da Expressão Gênica , Terapia Genética/métodos , Humanos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/diagnóstico , Neoplasias/genética , Neoplasias/terapia , Precursores de RNA/metabolismo , Processamento Pós-Transcricional do RNA , RNA Mitocondrial/metabolismo , RNA Ribossômico/metabolismo , Proteínas Ribossômicas/biossíntese , Proteínas Ribossômicas/fisiologia , Ribossomos/fisiologiaRESUMO
In this paper, we report our investigations on five T30175 analogues, prepared by replacing sequence thymidines with abasic sites (S) one at a time, in comparison to their natural counterpart in order to evaluate their antiproliferative potential and the involvement of the residues not belonging to the central core of stacked guanosines in biological activity. The collected NMR (Nuclear Magnetic Resonance), CD (Circular Dichroism), and PAGE (Polyacrylamide Gel Electrophoresis) data strongly suggest that all of them adopt G-quadruplex (G4) structures strictly similar to that of the parent aptamer with the ability to fold into a dimeric structure composed of two identical G-quadruplexes, each characterized by parallel strands, three all-anti-G-tetrads and four one-thymidine loops (one bulge and three propeller loops). Furthermore, their antiproliferative (MTT assay) and anti-motility (wound healing assay) properties against lung and colorectal cancer cells were tested. Although all of the oligodeoxynucleotides (ODNs) investigated here exhibited anti-proliferative activity, the unmodified T30175 aptamer showed the greatest effect on cell growth, suggesting that both its characteristic folding in dimeric form and its presence in the sequence of all thymidines are crucial elements for antiproliferative activity. This straightforward approach is suitable for understanding the critical requirements of the G-quadruplex structures that affect antiproliferative potential and suggests its application as a starting point to facilitate the reasonable development of G-quadruplexes with improved anticancer properties.
Assuntos
Antineoplásicos/química , Aptâmeros de Nucleotídeos/química , Neoplasias Colorretais/genética , Neoplasias Pulmonares/genética , Timidina/genética , Substituição de Aminoácidos , Antineoplásicos/farmacologia , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/farmacologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Dicroísmo Circular , Neoplasias Colorretais/tratamento farmacológico , Ensaios de Seleção de Medicamentos Antitumorais , Quadruplex G , Células HCT116 , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Espectroscopia de Ressonância MagnéticaRESUMO
Eukaryotic cells are exposed to many internal and external stimuli that affect their fate. In particular, the exposure to some of these stimuli induces stress triggering a variety of stress responses aimed to re-establish cellular homeostasis. It is now established that the deregulation of stress response pathways plays a central role in cancer initiation and progression, allowing the adaptation of cells to an altered state in the new environment. Autophagy is a tightly regulated pathway which exerts "housekeeping" role in physiological processes. Recently, a growing amount of evidence highlighted the crucial role of autophagy in the regulation of integrated stress responses, including nucleolar and endoplasmic reticulum. In this review, we attempt to afford an overview of the complex role of nucleolar and endoplasmic reticulum stress-response mechanisms in the regulation of autophagy in cancer and cancer treatment.
Assuntos
Autofagia/genética , Núcleo Celular/genética , Retículo Endoplasmático/genética , Neoplasias/genética , Apoptose/genética , Estresse do Retículo Endoplasmático/genética , Humanos , Neoplasias/patologiaRESUMO
The nucleolus is the site of ribosome biogenesis and has been recently described as important sensor for a variety of cellular stressors. In the last two decades, it has been largely demonstrated that many chemotherapeutics act by inhibiting early or late rRNA processing steps with consequent alteration of ribosome biogenesis and activation of nucleolar stress response. The overall result is cell cycle arrest and/or apoptotic cell death of cancer cells. Our previously data demonstrated that ribosomal protein uL3 is a key sensor of nucleolar stress activated by common chemotherapeutic agents in cancer cells lacking p53. We have also demonstrated that uL3 status is associated to chemoresistance; down-regulation of uL3 makes some chemotherapeutic drugs ineffective. Here, we demonstrate that in colon cancer cells, the uL3 status affects rRNA synthesis and processing with consequent activation of uL3-mediated nucleolar stress pathway. Transcriptome analysis of HCT 116p53-/- cells expressing uL3 and of a cell sub line stably depleted of uL3 treated with Actinomycin D suggests a new extra-ribosomal role of uL3 in the regulation of autophagic process. By using confocal microscopy and Western blotting experiments, we demonstrated that uL3 acts as inhibitory factor of autophagic process; the absence of uL3 is associated to increase of autophagic flux and to chemoresistance. Furthermore, experiments conducted in presence of chloroquine, a known inhibitor of autophagy, indicate a role of uL3 in chloroquine-mediated inhibition of autophagy. On the basis of these results and our previous findings, we hypothesize that the absence of uL3 in cancer cells might inhibit cancer cell response to drug treatment through the activation of cytoprotective autophagy. The restoration of uL3 could enhance the activity of many drugs thanks to its pro-apoptotic and anti-autophagic activity.
Assuntos
Nucléolo Celular/metabolismo , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Estresse Fisiológico , Apoptose/genética , Autofagia/genética , Ciclo Celular/genética , Linhagem Celular Tumoral , Neoplasias do Colo/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Espaço Intracelular/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Processamento Pós-Transcricional do RNA/genética , Estabilidade de RNA/genética , RNA Ribossômico/genética , Proteína Ribossômica L3 , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Transdução de Sinais/genéticaRESUMO
PURPOSE: In order to study novel therapeutic approaches taking advantage of natural compounds showing anticancer and anti-proliferative effects, we focused our interest on S-adenosyl-l-methionine, a naturally occurring sulfur-containing nucleoside synthesized from adenosine triphosphate and methionine by methionine adenosyltransferase, and its potential in overcoming drug resistance in colon cancer cells devoid of p53. RESULTS: In the present study, we demonstrated that S-adenosyl-l-methionine overcomes uL3-mediated drug resistance in p53 deleted colon cancer cells. In particular, we demonstrated that S-adenosyl-l-methionine causes cell cycle arrest at the S phase; inhibits autophagy; augments reactive oxygen species; and induces apoptosis in these cancer cells. CONCLUSIONS: Results reported in this paper led us to propose S-adenosyl-l-methionine as a potential promising agent for cancer therapy by examining p53 and uL3 profiles in tumors to yield a better clinical outcomes.
Assuntos
Neoplasias do Colo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Deleção de Genes , Proteínas Ribossômicas/metabolismo , S-Adenosilmetionina/farmacologia , Proteína Supressora de Tumor p53/deficiência , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Células HCT116 , Humanos , Proteína Ribossômica L3 , Proteínas Ribossômicas/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Despite advancements in therapeutic strategies, the development of drug resistance and metastasis remains a serious concern for the efficacy of chemotherapy against colorectal cancer (CRC). We have previously demonstrated that low expression of ribosomal protein uL3 positively correlates with chemoresistance in CRC patients. Here, we demonstrated that the loss of uL3 increased the metastatic capacity of CRC cells in chick embryos. Metabolomic analysis revealed large perturbations in amino acid and glutathione metabolism in resistant uL3-silenced CRC cells, indicating that uL3 silencing dramatically triggered redox metabolic reprogramming. RNA-Seq data revealed a notable dysregulation of 108 genes related to ferroptosis in CRC patients. Solute Carrier Family 7 Member 11 (SLC7A11) is one of the most dysregulated genes; its mRNA stability is negatively regulated by uL3, and its expression is inversely correlated with uL3 levels. Inhibition of SLC7A11 with erastin impaired resistant uL3-silenced CRC cell survival by inducing ferroptosis. Of interest, the combined treatment erastin plus uL3 enhanced the chemotherapeutic sensitivity of uL3-silenced CRC cells to erastin. The antimetastatic potential of the combined strategy was evaluated in chick embryos. Overall, our study sheds light on uL3-mediated chemoresistance and provides evidence of a novel therapeutic approach, erastin plus uL3, to induce ferroptosis, establishing individualized therapy by examining p53, uL3 and SLC7A11 profiles in tumors.
RESUMO
Colorectal cancer (CRC) often involves wild-type p53 inactivation by MDM2 and MDM4 overexpression, promoting tumor progression and resistance to 5-fluoruracil (5-FU). Disrupting the MDM2/4 heterodimer can proficiently reactivate p53, sensitizing cancer cells to 5-FU. Herein, we developed 16 peptides based on Pep3 (1), the only known peptide acting through this mechanism. The new peptides, notably 3 and 9, showed lower IC50 values than 1. When incorporated into tumor-targeted biodegradable nanoparticles, these exhibited cytotoxicity against three different CRC cell lines. Notably, NPs/9 caused a significant increase in p53 levels associated with a strong increment of its main downstream target p21 inducing apoptosis. Also, the combined treatment of 9 with 5-FU caused the activation of nucleolar stress and a synergic apoptotic effect. Hence, the co-delivery of MDM2/4 heterodimer disruptors with 5-FU through nanoparticles might be a promising strategy to overcome drug resistance in CRC.
Assuntos
Antineoplásicos , Neoplasias Colorretais , Nanopartículas , Humanos , Fluoruracila/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose , Peptídeos/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Linhagem Celular Tumoral , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas de Ciclo Celular/metabolismoRESUMO
Surface functionalization of nanoparticles (NPs) with tumor-targeting peptides is an emerging approach with a huge potential to translate in the clinic and ameliorate the efficacy of nano-oncologicals. One major challenge is to find straightforward strategies for anchoring peptides on the surface of biodegradable NPs and ensuring their correct exposure and orientation to bind the target receptor. Here, we propose a non-covalent strategy to functionalize polyester aminic NPs based on the formation of either electrostatic or lipophilic interactions between NPs and the peptide modified with an anchoring moiety. We selected an iNGRt peptide containing a CendR motif (CRNGR) targeting neuropilin receptor 1 (NRP-1), which is upregulated in several cancers. iNGRt was linked with either a short poly(glutamic acid) chain (polyE) or a palmitoyl chain (Palm) and used to functionalize the surface of NPs made of a diamine poly(ε-caprolactone). iNGRt-PolyE was adsorbed on preformed cationic NPs through electrostatic interaction, whereas iNGRt-Palm was integrated into the forming NPs through interactions. In both cases, peptides were strongly associated with NPs of â¼100 nm, low polydispersity indexes, and positive zeta potential values. NPs entered MDA-MB231 breast cancer cells overexpressing NRP-1 via receptor-mediated endocytosis and showed a different cell localization depending on the mode of peptide anchoring. When loaded with the lipophilic anticancer drug docetaxel (DTX), NPs functionalized with the iNGRt-Palm variant exerted a time- and dose-dependent cytotoxicity similar to DTX in MDA-MB-231 cells but were less toxic than DTX toward control MRC-5 human fibroblasts, not expressing NRP-1. In a heterotopic mouse model of triple negative breast cancer, iNGRt-Palm NPs were tolerated better than free DTX and demonstrated superior anticancer activity and survival compared to both free DTX and NPs without peptide functionalization. We foresee that the functionalization strategy with palmitoylated peptides proposed here can be extended to other biodegradable NPs and peptide sequences designed for therapeutic or targeting purposes.
Assuntos
Antineoplásicos , Nanopartículas , Neoplasias de Mama Triplo Negativas , Camundongos , Animais , Humanos , Docetaxel , Antineoplásicos/farmacologia , Polímeros , Peptídeos , Linhagem Celular Tumoral , Portadores de FármacosRESUMO
It is now well established that the urothelium does not act as a passive barrier but contributes to bladder homeostasis by releasing several signaling molecules in response to physiological and chemical stimuli. Here, we investigated the potential contribution of the hydrogen sulfide (H2S) pathway in regulating human urothelium function in ß3 adrenoceptor-mediated relaxation. The relaxant effect of BRL 37344 (0.1-300 µM), a selective ß3 adrenoceptor agonist, was evaluated in isolated human bladder strips in the presence or absence of the urothelium. The relaxant effect of BRL 37344 was significantly reduced by urothelium removal. The inhibition of cystathionine-γ-lyase (CSE), but not cystathionine-ß-synthase (CBS), significantly reduced the BRL 37344 relaxing effect to the same extent as that given by urothelium removal, suggesting a role for CSE-derived H2S. ß3 adrenoceptor stimulation in the human urothelium or in T24 urothelial cells markedly increased H2S and cAMP levels that were reverted by a blockade of CSE and ß3 adrenoceptor antagonism. These findings demonstrate a key role for urothelium CSE-derived H2S in the ß3 effect on the human bladder through the modulation of cAMP levels. Therefore, the study establishes the relevance of urothelial ß3 adrenoceptors in the regulation of bladder tone, supporting the use of ß3 agonists in patients affected by an overactive bladder.
RESUMO
The antiproliferative G-quadruplex aptamers are a promising and challenging subject in the framework of the anticancer therapeutic oligonucleotides research field. Although several antiproliferative G-quadruplex aptamers have been identified and proven to be effective on different cancer cell lines, their mechanism of action is still unexplored. We have recently described the antiproliferative activity of a heterochiral thrombin binding aptamer (TBA) derivative, namely, LQ1. Here, we investigate the molecular mechanisms of LQ1 activity and the structural and antiproliferative properties of two further TBA derivatives, differing from LQ1 only by the small loop base-compositions. We demonstrate that in p53 deleted colon cancer cells, LQ1 causes nucleolar stress, impairs ribosomal RNA processing, leading to the accumulation of pre-ribosomal RNAs, arrests cells in the G2/M phase and induces early apoptosis. Importantly, the depletion of uL3 abrogates all these effects, indicating that uL3 is a crucial player in the mechanism of action of LQ1. Taken together, our findings identify p53-independent and uL3-dependent nucleolar stress as a novel stress response pathway activated by a specific G-quadruplex TBA derivative. To the best of our knowledge, this investigation reveals, for the first time, the involvement of the nucleolar stress pathway in the mechanism of action of antiproliferative G-quadruplex aptamers.
Assuntos
Aptâmeros de Nucleotídeos/farmacologia , Nucléolo Celular/metabolismo , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Quadruplex G , Proteínas Ribossômicas/metabolismo , Estresse Fisiológico , Apoptose/efeitos dos fármacos , Aptâmeros de Nucleotídeos/química , Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Nucléolo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Humanos , Processamento Pós-Transcricional do RNA/efeitos dos fármacos , RNA Ribossômico/genética , Proteína Ribossômica L3 , Estresse Fisiológico/efeitos dos fármacosRESUMO
The nucleolus is a distinct sub-cellular compartment structure in the nucleus. First observed more than 200 years ago, the nucleolus is detectable by microscopy in eukaryotic cells and visible during the interphase as a sub-nuclear structure immersed in the nucleoplasm, from which it is not separated from any membrane. A huge number of studies, spanning over a century, have identified ribosome biogenesis as the main function of the nucleolus. Recently, novel functions, independent from ribosome biogenesis, have been proposed by several proteomic, genomic, and functional studies. Several works have confirmed the non-canonical role for nucleoli in regulating important cellular processes including genome stability, cell-cycle control, the cellular senescence, stress responses, and biogenesis of ribonucleoprotein particles (RNPs). Many authors have shown that both canonical and non-canonical functions of the nucleolus are associated with several cancer-related processes. The association between the nucleolus and cancer, first proposed by cytological and histopathological studies showing that the number and shape of nucleoli are commonly altered in almost any type of cancer, has been confirmed at the molecular level by several authors who demonstrated that numerous mechanisms occurring in the nucleolus are altered in tumors. Recently, therapeutic approaches targeting the nucleolus in cancer have started to be considered as an emerging "hallmark" of cancer and several therapeutic interventions have been developed. This review proposes an up-to-date overview of available strategies targeting the nucleolus, focusing on novel targeted therapeutic approaches. Finally, a target-based classification of currently available treatment will be proposed.
Assuntos
Antineoplásicos/farmacologia , Nucléolo Celular/efeitos dos fármacos , Neoplasias/patologia , Neoplasias/terapia , Animais , Nucléolo Celular/metabolismo , Nucléolo Celular/patologia , Humanos , Neoplasias/metabolismo , Proteína Ribossômica L3RESUMO
Several experimental strategies in the treatment of cancer include drug alteration of cell cycle regulatory pathways as a useful strategy. Extra-ribosomal functions of human ribosomal protein L3 (uL3) may affect DNA repair, cell cycle arrest and apoptosis. In the present study, we demonstrated that uL3 is required for the activation of G1/S transition genes. Luciferase assays established that uL3 negatively regulates the activity of E2F1 promoter. Induced ribosome-free uL3 reduces Cyclin D1 mRNA and protein levels. Using protein/protein immunoprecipitation methods, we demonstrated that uL3 physically interacts with PARP-1 affecting E2F1 transcriptional activity. Our findings led to the identification of a new pathway mediated by uL3 involving E2F1 and Cyclin D1 in the regulation of cell cycle progression.