Cellular modulation of a G-quadruplex structure found in the lung cancer-related microRNA-3196 Daniela Alexandre, Joana Polido, André Miranda, Robert H.E. Hudson, David Monchaud, Pedro V. Baptista, Carla Cruz International Journal of Biological Macromolecules, 2025 RNA G-quadruplexes (G4s) are promising drug targets due to their high cellular abundance. G-rich RNA regions inherently form G4 structures, while GC-rich sequences adopt stem-loop conformations, and their dynamic equilibrium critically influences RNA function. MicroRNAs (miRs), key regulators of protein expression, undergo processing by Dicer, which specifically recognizes stem-loop structures in precursor miRs (pre-miRs). Notably, some pre-miRs containing G4-forming sequences influence Dicer cleavage, suggesting that G4s can directly regulate miR production. Moreover, pre-miRs with G4 structures present promising targets for small molecules. This research focuses on identifying and modulating G4 structure in pre-miR-3196 to restore normal lung cancer (LC) levels, offering a potential therapeutic strategy. Firstly, bioinformatic analyses indicated the presence of G4 motifs in pre-miR-3196. We then demonstrated in vitro that this RNA sequence folds into stable G4s by a combination of biophysical and biochemical assays. Then, we demonstrated the formation of these G4s in human cancer cells by confocal imaging before showing that these G4s can be modulated using the RNA G4 destabilizer PhpC, which impacts the miR-3196 biogenesis. These findings highlighted the possibility of using G4s to control the expression of mature miR-3196 and revealed the potential of using the destabilizer PhpC to adjust its G4 structure.
Sensitive fluorescent detection of SARS-CoV-2 RNA using an enzymatic-based method André Miranda, Bruno Baptista, Marília Figueira, Fani Sousa, Cláudio J. Maia, Silvia Socorro, Carla Cruz Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2025 • Sensitive detection of SARS-CoV-2 RNA using HNESA method. • Cyclic amplification involves one assistant probe and one molecular beacon. • Molecular beacon amplified the fluorescence signal of the target sequence. • The method is fast, sensitive and efficient. Rapid, quantitative, and sensitive detection of viral oligonucleotides can help to diagnose the infection before symptoms occur, monitor disease progression, and identify viral subtypes. A one-pot, simple, rapid hairpin-mediated nicking enzymatic signal amplification (HNESA) method was previously developed for nucleic acids detection. In the present work, this method was applied for the detection of SARS-CoV-2 RNA by designing an assistant probe (AP) that contains the complementary sequence for the target, the sequence of hybridization with the loop region of the molecular beacon (MB), and the recognition site of the nicking endonuclease Nt.BstNBI. MB sequences (MB1 and MB2) were also designed and optimized in length and nucleotide composition. MB2 significantly amplified the fluorescence signal of the target sequence. The linear range was from 0.1 to 1 nM with a detection limit of 170.6 pM. Results can be obtained within 45 min, considering that the cyclic amplification involves only one AP and one MB. Based on this, the use of HNESA for diagnosing viral diseases, such as SARS-CoV-2, could be a complementary approach to polymerase chain reaction (PCR), and it is a technique that is quick, efficient and has high sensitivity.
Exploring the G-Quadruplex Formation of AS1411 Derivatives Pedro Lourenço, David Moreira, André Miranda, Jéssica Lopes-Nunes, Izamara Maocha, Tiago Santos, Pedro L. Ferreira, Fani Sousa, Artur Paiva, Carla Cruz Molecules, 2025 AS1411 is a G-quadruplex (G4) aptamer that binds tightly to nucleolin (NCL) on the cell surface and has shown strong anticancer effects. However, this aptamer is highly polymorphic, presenting different types of G4s, which may hinder its preclinical application. Several modifications have been made to decrease the polymorphism of this aptamer. In this work, we designed six AS1411 derivatives by substituting guanine with thymine in the central linker and modifying the number of thymines either in the linker itself and/or at both ends of the sequence. The G4 formation, stability, and NCL binding were evaluated by several biophysical techniques and computational and cell studies. Overall, a decrease in polymorphism of G4-forming sequences compared to AS1411 is observed by size exclusion chromatography (SEC) and circular dichroism (CD) spectroscopy in the presence of potassium salt. The melting experiments reveal a higher ability of the derivatives without thymine at both sequence ends to form a G4, consistent with the G4H score predictions. Additionally, it is possible to conclude that deletions of T in the central core increase the ability to form G4. Moreover, the AS1411 derivatives bind NCL with high affinity (KD values in the 10−9 M range), particularly the sequences with only thymine modifications in the central linker. In silico studies reveal structural insights and demonstrate that AS1411 derivatives interact with NCL, establishing multiple interactions with the different domains, thereby further supporting the experimental findings. By using a lung cancer cell line with high cell surface NCL expression, we evaluate the internalization and uptake of AS1411 derivatives, identifying the derivative-lacking thymines in the central core as the ones with the highest internalization and cellular uptake.
I-motif formation in the promoter region of the B-MYB proto-oncogene André Alves, André Miranda, Irene Zanin, Sara N. Richter, Jean-Louis Mergny, Carla Cruz International Journal of Biological Macromolecules, 2025 Understanding the mechanisms of carcinogenesis is essential to combat cancer. The search for alternative targets for anticancer therapy has gained interest, particularly when focused on upstream pathways. This strategy is particularly relevant when the encoded target proteins are known - or believed - to be "undruggable", as has been reported for the B-MYB oncogene. This gene, which regulates survival and cell cycle regulation, is overexpressed in cancer and correlates with an unfavorable prognosis. In this study, we focused on the identification of the i-motif (iM) structures in the promoter region of B-MYB as a possible anticancer target, with a complete biophysical characterization and in cell formation assessment using iM-CUT&Tag. Additionally, the interaction of the iM structures with a library of small molecules was investigated.
Synthesis of 1,10-Phenanthroline-2,9-bistriazoles: Evaluation as G-Quadruplex Binders and Anti-Tumor Activity Joana Figueiredo, Israel Carreira‐Barral, Pedro Lourenço, André Miranda, Jéssica Lopes‐Nunes, Roberto Quesada, Mafalda Laranjo, Jean‐Louis Mergny, Carla Cruz Chemmedchem, 2025 Novel 1,10‐phenanthroline‐2,9‐bistriazoles derivatives have been synthesized by copper‐catalyzed azide/alkyne cycloaddition reactions and assessed for their ability to bind and stabilize G‐quadruplex (G4) structures. Ten novel compounds were evaluated using Förster resonance energy transfer (FRET) melting, circular dichroism (CD), and fluorescence spectroscopy on several G4 sequences. Biophysical characterization led to the identification of compounds 4 a, 4 b, and 5 b as good G4 ligands of KRAS G4 sequences. The impact on cell viability of all derivatives was also assessed, revealing weak effects. However, compound 2 a exhibited cytotoxicity activity on A549 and H1299 cancer cells and low cytotoxicity towards MRC‐5 non‐malignant cells MRC‐5 not connected with its G4‐binding ability. Flow cytometry showed that 2 a induced a cell viability decrease in S and G2/M phases for A549 and H1299; thus, more studies should be performed to explore the proteins involved in cell cycle regulation.
Detecting mir-155-3p through a Molecular Beacon Bead-Based Assay David Moreira, Daniela Alexandre, André Miranda, Pedro Lourenço, Pedro V. Baptista, Cândida Tomaz, Yi Lu, Carla Cruz Molecules, 2024 Lung cancer (LC) is recognized as one of the most prevalent and lethal cancers worldwide, underscoring an urgent need for innovative diagnostic and therapeutic approaches. MicroRNAs (miRNAs) have emerged as promising biomarkers for several diseases and their progression, such as LC. However, traditional methods for detecting and quantifying miRNAs, such as PCR, are time-consuming and expensive. Herein, we used a molecular beacon (MB) bead-based assay immobilized in a microfluidic device to detect miR-155-3p, which is frequently overexpressed in LC. The assay relies on the fluorescence enhancement of the MB upon binding to the target miRNA via Watson and Crick complementarity, resulting in a conformational change from a stem–loop to a linear structure, thereby bringing apart the fluorophores at each end. This assay was performed on a microfluidic platform enabling rapid and straightforward target detection. We successfully detected miR-155-3p in a saline solution, obtaining a limit of detection (LOD) of 42 nM. Furthermore, we evaluated the method’s performance in more complex biological samples, including A549 cells’ total RNA and peripheral blood mononuclear cells (PBMCs) spiked with the target miRNA. We achieved satisfactory recovery rates, especially in A549 cells’ total RNA.
G-quadruplex forming motifs in the promoter region of the B-MYB proto-oncogene André Miranda, Anne Cucchiarini, Cyril Esnault, Jean-Christophe Andrau, Paula A. Oliveira, Jean-Louis Mergny, Carla Cruz International Journal of Biological Macromolecules, 2024 To combat cancer, a comprehensive understanding of the molecular mechanisms and behaviors involved in carcinogenesis is crucial, as tumorigenesis is a complex process influenced by various genetic events and disease hallmarks. The B-MYB gene encodes a transcription factor involved in cell cycle regulation, survival, and differentiation in normal cells. B-MYB can be transformed into an oncogene through mutations, and abnormal expression of B-MYB has been identified in various cancers, including lung cancer, and is associated with poor prognosis. Targeting this oncogene is a promising approach for anti-cancer drug design. B-MYB has been deemed undruggable in previous reports, necessitating the search for novel therapeutic options. In this study, we found that the B-MYB gene promoter contains several G/C rich motifs compatible with G-quadruplex (G4) formation. We investigated and validated the existence of G4 structures in the promoter region of B-MYB, first in vitro using a combination of bioinformatics, biophysical, and biochemical methods, then in cell with the recently developed G4access method.
Targeting proto-oncogene B-MYB G-quadruplex with a nucleic acid–based fluorescent probe Pedro Lourenço, André Miranda, Maria Paula Cabral Campello, António Paulo, Jean Louis-Mergny, Carla Cruz International Journal of Biological Macromolecules, 2024 The B-MYB gene encodes a transcription factor (B-Myb) that regulates cell growth and survival. Abnormal expression of B-MYB is frequently observed in lung cancer and poses challenges for targeted drug therapy. Oncogenes often contain DNA structures called G-quadruplexes (G4s) in their promoter regions, and B-MYB is no exception. These G4s play roles in genetic regulation and are potential cancer treatment targets. In this study, a probe was designed to specifically identify a G4 within the promoter region of the B-MYB gene. This probe combines an acridine derivative ligand with a DNA segment complementary to the target sequence, enabling it to hybridize with the adjacent sequence of the G4 being investigated. Biophysical studies demonstrated that the acridine derivative ligands C5NH2 and C8NH2 not only effectively stabilized the G4 structure but also exhibited moderate affinity. They were capable of altering the G4 topology and exhibited enhanced fluorescence emission in the presence of this quadruplex. Additionally, these ligands increased the number of G4s observed in cellular studies. Through various biophysical studies, the target sequence was shown to form a G4 structure, even with an extra nucleotide tail added to its flanking region. Cellular studies confirmed the co-localization between the target sequence and the developed probe.
Targeting of G-quadruplex DNA with 99mTc(I)/Re(I) Tricarbonyl Complexes Carrying Pyridostatin Derivatives Elisa Palma, Cigdem Içhedef, Célia Fernandes, Ana Belchior, Paula Raposinho, Lurdes Gano, André Miranda, David Moreira, Pedro Lourenço, Carla Cruz, Ana Salomé Pires, Maria Filomena Botelho, António Paulo Chemistry A European Journal, 2024 The main goal of this work was to elucidate the potential relevance of (radio)metal chelates of 99mTc and Re targeting G‐quadruplex structures for the design of new tools for cancer theranostics. 99mTc provides the complexes with the ability to perform single‐photon‐emission computed tomography imaging studies, while the Re complexes should act as anticancer agents upon interaction with specific G4 DNA or RNA structures present in tumor tissues. Towards this goal, we have developed isostructural 99mTc(I) and Re(I) tricarbonyl complexes anchored by a pyrazolyl‐diamine (Pz) chelator carrying a pendant pyridostatin (PDS) fragment as the G4‐binding motif. The interaction of the PDF‐Pz‐Re (8) complex with different G4‐forming oligonucleotides was studied by circular dichroism, fluorescence spectroscopy and FRET‐melting assays. The results showed that the Re complex retained the ability to bind and stabilize G4‐structures from different DNA or RNA sequences, namely those present on the SRC proto‐oncogene and telomeric RNA (TERRA sequence). PDF‐Pz‐Re (8) showed low to moderate cytotoxicity in PC3 and MCF‐7 cancer cell lines, as typically observed for G4‐binders. Biodistribution studies of the congener PDF‐Pz‐99mTc (12) in normal mice showed that the complex undergoes a fast blood clearance with a predominant hepatobiliary excretion, pointing also for a high in vitro stability.
Stabilization of a DNA aptamer by ligand binding Tiago Santos, Jéssica Lopes-Nunes, Daniela Alexandre, André Miranda, Joana Figueiredo, Micael S. Silva, Jean-Louis Mergny, Carla Cruz Biochimie, 2022
Pre-miRNA-149 G-quadruplex as a molecular agent to capture nucleolin Tiago Santos, André Miranda, Lionel Imbert, Andreia Jardim, Catarina R.F. Caneira, Virgínia Chu, João P. Conde, Maria Paula Cabral Campello, António Paulo, Gilmar Salgado, Eurico J. Cabrita, Carla Cruz European Journal of Pharmaceutical Sciences, 2022
Therapeutic Applications of Nucleic Acid Aptamers P Lourenço, D Moreira, D Alexandre, I Maocha, J Lopes-Nunes, ... Springer Handbook of Medical Biotechnology, 395-427 , 2025 2025
Cellular modulation of a G-quadruplex structure found in the lung cancer-related microRNA-3196 D Alexandre, J Polido, A Miranda, RHE Hudson, D Monchaud, ... International Journal of Biological Macromolecules 318, 145263 , 2025 2025 Citations: 9
The Potential of B-myb G-quadruplex in Cancer Therapy: Insights into Formation, Small Molecule Binding and Biological Outcomes A Miranda, A Cucchiarinni, CEC Esnault, JC Andrau, P Oliveira, ... EUROPEAN BIOPHYSICS JOURNAL 54, S152-S152 , 2025 2025
Sensitive fluorescent detection of SARS-CoV-2 RNA using an enzymatic-based method A Miranda, B Baptista, M Figueira, F Sousa, CJ Maia, S Socorro, C Cruz Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 331, 125766 , 2025 2025
Exploring the G-quadruplex formation of AS1411 derivatives P Lourenço, D Moreira, A Miranda, J Lopes-Nunes, I Maocha, T Santos, ... Molecules 30 (8), 1673 , 2025 2025 Citations: 6
I-motif formation in the promoter region of the B-MYB proto-oncogene A Alves, A Miranda, I Zanin, SN Richter, JL Mergny, C Cruz International Journal of Biological Macromolecules 296, 139582 , 2025 2025 Citations: 4
Detecting mir-155-3p through a Molecular Beacon Bead-Based Assay D Moreira, D Alexandre, A Miranda, P Lourenco, PV Baptista, C Tomaz, ... Molecules 29 (13), 3182 , 2024 2024 Citations: 3
G-quadruplex forming motifs in the promoter region of the B-MYB proto-oncogene A Miranda, A Cucchiarini, C Esnault, JC Andrau, PA Oliveira, JL Mergny, ... International Journal of Biological Macromolecules 270, 132244 , 2024 2024 Citations: 3
Targeting proto-oncogene B-MYB G-quadruplex with a nucleic acid–based fluorescent probe P Lourenco, A Miranda, MPC Campello, A Paulo, J Louis-Mergny, C Cruz International Journal of Biological Macromolecules 266, 131055 , 2024 2024 Citations: 5
Targeting of G‐quadruplex DNA with 99m Tc(I)/Re(I) Tricarbonyl Complexes Carrying Pyridostatin Derivatives E Palma, C Içhedef, C Fernandes, A Belchior, P Raposinho, L Gano, ... Chemistry–A European Journal 30 (22), e202400285 , 2024 2024 Citations: 4
Synthesis of 1, 10‐phenanthroline‐2, 9‐bistriazoles: Evaluation as G‐quadruplex binders and anti‐tumor activity J Figueiredo, I Carreira-Barral, P Lourenço, A Miranda, J Lopes Nunes, ... ChemMedChem, e202400591 , 2024 2024 Citations: 1
Gallic acid–triethylene glycol aptadendrimers synthesis, biophysical characterization and cellular evaluation A Miranda, R Lopez-Blanco, J Lopes-Nunes, AM Melo, MPC Campello, ... Pharmaceutics 14 (11), 2456 , 2022 2022 Citations: 8
G-quadruplex aptamer-ligand characterization D Moreira, D Leitão, J Lopes-Nunes, T Santos, J Figueiredo, A Miranda, ... Molecules 27 (20), 6781 , 2022 2022 Citations: 14
Stabilization of a DNA aptamer by ligand binding T Santos, J Lopes-Nunes, D Alexandre, A Miranda, J Figueiredo, ... Biochimie 200, 8-18 , 2022 2022 Citations: 26
Aptamer-based microfluidics for circulating tumor cells C Cruz, A Miranda, T Santos Aptamers Engineered Nanocarriers for Cancer Therapy 1, 556 , 2022 2022 Citations: 3
Targeting a G-quadruplex from let-7e pre-miRNA with small molecules and nucleolin T Santos, A Miranda, L Imbert, D Monchaud, GF Salgado, EJ Cabrita, ... Journal of Pharmaceutical and Biomedical Analysis 215, 114757 , 2022 2022 Citations: 15
Pre-miRNA-149 G-quadruplex as a molecular agent to capture nucleolin T Santos, A Miranda, L Imbert, A Jardim, CRF Caneira, V Chu, JP Conde, ... European Journal of Pharmaceutical Sciences 169, 106093 , 2022 2022 Citations: 11
Molecular Beacon assay development for severe acute respiratory syndrome coronavirus 2 detection J Carvalho, J Lopes-Nunes, J Figueiredo, T Santos, A Miranda, ... Sensors 21 (21), 7015 , 2021 2021 Citations: 11
Ligands as stabilizers of G-Quadruplexes in non-coding RNAs J Figueiredo, T Santos, A Miranda, D Alexandre, B Teixeira, P Simões, ... Molecules 26 (20), 6164 , 2021 2021 Citations: 19
Recognition of nucleolin through interaction with RNA G-quadruplex T Santos, A Miranda, MPC Campello, A Paulo, G Salgado, EJ Cabrita, ... Biochemical Pharmacology 189, 114208 , 2021 2021 Citations: 38
MOST CITED SCHOLAR PUBLICATIONS
Recognition of nucleolin through interaction with RNA G-quadruplex T Santos, A Miranda, MPC Campello, A Paulo, G Salgado, EJ Cabrita, ... Biochemical Pharmacology 189, 114208 , 2021 2021 Citations: 38
Locking up the AS1411 aptamer with a flanking duplex: towards an improved nucleolin-targeting A Miranda, T Santos, E Largy, C Cruz Pharmaceuticals 14 (2), 121 , 2021 2021 Citations: 36
Targeting Nucleolin By RNA G-Quadruplex-Forming Motif J Figueiredo, A Miranda, J Lopes-Nunes, J Carvalho, D Alexandre, ... Biochemical Pharmacology, 114418 , 2020 2020 Citations: 31
Stabilization of a DNA aptamer by ligand binding T Santos, J Lopes-Nunes, D Alexandre, A Miranda, J Figueiredo, ... Biochimie 200, 8-18 , 2022 2022 Citations: 26
Aptamer-based approaches to detect nucleolin in prostate cancer A Miranda, T Santos, J Carvalho, D Alexandre, A Jardim, CRF Caneira, ... Talanta 226, 122037 , 2021 2021 Citations: 26
Ligands as stabilizers of G-Quadruplexes in non-coding RNAs J Figueiredo, T Santos, A Miranda, D Alexandre, B Teixeira, P Simões, ... Molecules 26 (20), 6164 , 2021 2021 Citations: 19
Targeting a G-quadruplex from let-7e pre-miRNA with small molecules and nucleolin T Santos, A Miranda, L Imbert, D Monchaud, GF Salgado, EJ Cabrita, ... Journal of Pharmaceutical and Biomedical Analysis 215, 114757 , 2022 2022 Citations: 15
G-quadruplex aptamer-ligand characterization D Moreira, D Leitão, J Lopes-Nunes, T Santos, J Figueiredo, A Miranda, ... Molecules 27 (20), 6781 , 2022 2022 Citations: 14
Pre-miRNA-149 G-quadruplex as a molecular agent to capture nucleolin T Santos, A Miranda, L Imbert, A Jardim, CRF Caneira, V Chu, JP Conde, ... European Journal of Pharmaceutical Sciences 169, 106093 , 2022 2022 Citations: 11
Molecular Beacon assay development for severe acute respiratory syndrome coronavirus 2 detection J Carvalho, J Lopes-Nunes, J Figueiredo, T Santos, A Miranda, ... Sensors 21 (21), 7015 , 2021 2021 Citations: 11
Cellular modulation of a G-quadruplex structure found in the lung cancer-related microRNA-3196 D Alexandre, J Polido, A Miranda, RHE Hudson, D Monchaud, ... International Journal of Biological Macromolecules 318, 145263 , 2025 2025 Citations: 9
Gallic acid–triethylene glycol aptadendrimers synthesis, biophysical characterization and cellular evaluation A Miranda, R Lopez-Blanco, J Lopes-Nunes, AM Melo, MPC Campello, ... Pharmaceutics 14 (11), 2456 , 2022 2022 Citations: 8
Exploring the G-quadruplex formation of AS1411 derivatives P Lourenço, D Moreira, A Miranda, J Lopes-Nunes, I Maocha, T Santos, ... Molecules 30 (8), 1673 , 2025 2025 Citations: 6
Targeting proto-oncogene B-MYB G-quadruplex with a nucleic acid–based fluorescent probe P Lourenco, A Miranda, MPC Campello, A Paulo, J Louis-Mergny, C Cruz International Journal of Biological Macromolecules 266, 131055 , 2024 2024 Citations: 5
I-motif formation in the promoter region of the B-MYB proto-oncogene A Alves, A Miranda, I Zanin, SN Richter, JL Mergny, C Cruz International Journal of Biological Macromolecules 296, 139582 , 2025 2025 Citations: 4
Targeting of G‐quadruplex DNA with 99m Tc(I)/Re(I) Tricarbonyl Complexes Carrying Pyridostatin Derivatives E Palma, C Içhedef, C Fernandes, A Belchior, P Raposinho, L Gano, ... Chemistry–A European Journal 30 (22), e202400285 , 2024 2024 Citations: 4
Detecting mir-155-3p through a Molecular Beacon Bead-Based Assay D Moreira, D Alexandre, A Miranda, P Lourenco, PV Baptista, C Tomaz, ... Molecules 29 (13), 3182 , 2024 2024 Citations: 3
G-quadruplex forming motifs in the promoter region of the B-MYB proto-oncogene A Miranda, A Cucchiarini, C Esnault, JC Andrau, PA Oliveira, JL Mergny, ... International Journal of Biological Macromolecules 270, 132244 , 2024 2024 Citations: 3
Aptamer-based microfluidics for circulating tumor cells C Cruz, A Miranda, T Santos Aptamers Engineered Nanocarriers for Cancer Therapy 1, 556 , 2022 2022 Citations: 3
Synthesis of 1, 10‐phenanthroline‐2, 9‐bistriazoles: Evaluation as G‐quadruplex binders and anti‐tumor activity J Figueiredo, I Carreira-Barral, P Lourenço, A Miranda, J Lopes Nunes, ... ChemMedChem, e202400591 , 2024 2024 Citations: 1