Publications in the Year: 2024

Journal Article

Cunha, {JC }, Roma-Rodrigues C, Ferreira {JRM }, Baptista {PV}, Fernandes {AR}, Guieu S, Marques M{MB }.  2024.  Discovery of Novel Fluorescent Azaindoles with Cytotoxic Action in A2780 Ovarian Carcinoma Cells. Chemmedchem. 19, Number 20: John Wiley & Sons, Ltd. Abstract

Azaindole scaffold is a privileged structure in medicinal chemistry and some derivatives have demonstrated to be potential anticancer drugs. Herein, a set of novel azaindoles, comprising the four regioisomers, bearing a morpholine (azaindoles 3a-d) and N-methyl-N-benzylamine (azaindoles 4a-d) groups were prepared. Among these compounds, azaindoles 4 exhibited higher cytotoxicity against the ovarian cancer cell line A2780 and normal dermal fibroblasts compared to azaindoles 3. Furthermore, azaindoles 4b and 4c promoted a delay in the cell cycle of the cancer cell line, inspiring an investigation into the intracellular localization of these derivatives.

Cordeiro, S, Oliveira {BB }, Valente R, Ferreira D, Luz A, Baptista {PV}, Fernandes {AR}.  2024.  Breaking the mold: 3D cell cultures reshaping the future of cancer research. Frontiers in Cell and Developmental Biology. 12: Frontiers Media Abstract

Despite extensive efforts to unravel tumor behavior and develop anticancer therapies, most treatments fail when advanced to clinical trials. The main challenge in cancer research has been the absence of predictive cancer models, accurately mimicking the tumoral processes and response to treatments. The tumor microenvironment (TME) shows several human-specific physical and chemical properties, which cannot be fully recapitulated by the conventional 2D cell cultures or the in vivo animal models. These limitations have driven the development of novel in vitro cancer models, that get one step closer to the typical features of in vivo systems while showing better species relevance. This review introduces the main considerations required for developing and exploiting tumor spheroids and organoids as cancer models. We also detailed their applications in drug screening and personalized medicine. Further, we show the transition of these models into novel microfluidic platforms, for improved control over physiological parameters and high-throughput screening. 3D culture models have provided key insights into tumor biology, more closely resembling the in vivo TME and tumor characteristics, while enabling the development of more reliable and precise anticancer therapies.

Ferreira, D, Fernandes {AR}, Baptista {PV}.  2024.  Mild hyperthermia via gold nanoparticles and visible light irradiation for enhanced siRNA and ASO delivery in 2D and 3D tumour spheroids. Cancer Nanotechnology. 15, Number 1: Springer Science + Business Media Abstract

Background: The delivery of therapeutic nucleic acids, such as small interfering RNA (siRNA) and antisense oligonucleotides (ASO) into cells, is widely used in gene therapy. Gold nanoparticles (AuNPs) have proved to be effective in delivering silencing moieties with high efficacy. Moreover, AuNPs offer the possibility of spatial–temporal triggering of cell uptake through light irradiation due to their unique optical properties. Our study focuses on the use of AuNPs as improved vectorisation agents through mild photothermy triggered by visible light irradiation. This method promotes the transfection of oligonucleotides for gene silencing in 2D cells and more complex 3D spheroids. Results: Improving gene silencing strategies in 3D cell cultures is crucial since it provides more effective in vitro models to study cellular responses that closely resemble the in vivo tumour microenvironment. We demonstrate the potential of mild photothermy by effectively silencing the GFP gene in 2D cell cultures: HCT116 and MCF-7. Then we showed that mild photothermy could be effectively used for silencing the c-MYC oncogene transcript, which is greatly overexpressed in cancer cells. A decrease of 25% and 30% in c-MYC expression was observed in HCT116 2D cells and 7-day 3D spheroids, respectively. Conclusions: In summary, our findings offer a novel transfection approach for gene therapy applications in 2D and 3D tumour models. This approach is based on the use of mild photothermy mediated by AuNPs combined with visible laser irradiation that might pave the way for the spatial–temporal control of gene modulation.

Choroba, K, Machura B, Erfurt K, Casimiro {AR}, Cordeiro S, Baptista {PV}, Fernandes {AR}.  2024.  Copper(II) Complexes with 2,2′:6′,2″-Terpyridine Derivatives Displaying Dimeric Dichloro−μ-Bridged Crystal Structure: Biological Activities from 2D and 3D Tumor Spheroids to In Vivo Models. Journal Of Medicinal Chemistry. 67:5813–5836., Number 7: ACS - American Chemical Society Abstract

Eight 2,2′:6′,2″-terpyridines, substituted at the 4′-position with aromatic groups featuring variations in π-conjugation, ring size, heteroatoms, and methoxy groups, were employed to enhance the antiproliferative potential of [Cu2Cl2(R-terpy)2](PF6)2. Assessing the cytotoxicity in A2780 (ovarian carcinoma), HCT116 (colorectal carcinoma), and HCT116DoxR (colorectal carcinoma resistant to doxorubicin) and normal primary fibroblasts revealed that Cu(II) complexes with 4-quinolinyl, 4-methoxy-1-naphthyl, 2-furanyl, and 2-pyridynyl substituents showed superior therapeutic potential in HCT116DoxR cells with significantly reduced cytotoxicity in normal fibroblasts (42-129× lower). Besides their cytotoxicity, the Cu(II) complexes are able to increase intracellular ROS and interfere with cell cycle progression, leading to cell death by apoptosis and autophagy. Importantly, they demonstrated antimetastatic and antiangiogenic properties without in vivo toxicity. In accordance with their nuclear accumulation, the Cu(II) complexes are able to cleave pDNA and interact with bovine serum albumin, which is a good indication of their ability for internalization and transport toward tumor cells.

Bravo, {AC}, Morão B, Luz A, Dourado R, Oliveira B, Guedes A, Moreira-Barbosa C, Fidalgo C, Mascarenhas-Lemos L, Costa-Santos {MP}, Maio R, Paulino J, {Viana Baptista} P, Fernandes {AR}, Cravo M.  2024.  Bringing Hope to Improve Treatment in Pancreatic Ductal Adenocarcinoma: A New Tool for Molecular Profiling of KRAS Mutations in Tumor and Plasma Samples, oct. Cancers. 16, Number 20: MDPI - Multidisciplinary Digital Publishing Institute Abstract

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) incidence is rising, and prognosis remains poor due to late diagnosis and limited effective therapies. Currently, patients are treated based on TNM staging, without molecular tumor characterization. This study aimed to validate a technique that combines the amplification refractory mutation system (ARMS) with high-resolution melting analysis (HRMA) for detecting mutations in codon 12 of KRAS in tumor and plasma, and to assess its prognostic value. Methods: Prospective study including patients with newly diagnosed PDAC with tumor and plasma samples collected before treatment. Mutations in codon 12 of KRAS (G12D, G12V, G12C, and G12R) were detected using ARMS–HRMA and compared to Sanger sequencing (SS). Univariate and multivariate analyses were used to evaluate the prognostic significance of these mutations. Results: A total of 88 patients, 93% with ECOG-PS 0–1, 57% with resectable disease. ARMS–HRMA technique showed a higher sensitivity than SS, both in tumor and plasma (77% vs. 51%; 25 vs. 0%, respectively). The most frequent mutation was G12D (n = 32, 36%), followed by G12V (n = 22, 25%). On multivariate analysis, patients with G12D and/or G12C mutations, either in tumor or plasma, had lower PFS (HR 1.792, 95% CI 1.061–3.02

Oliveira, {BB }, Fernandes {AR}, Baptista {PV}.  2024.  Shrinking Cancer Research Barriers: Crafting Accessible Tumor-on-Chip Device for Gene Silencing Assays. Advanced Engineering Materials. : John Wiley & Sons, Ltd. Abstract

Tumor-on-chip (ToC) is crucial to bridge the gap between traditional cell culture experiments and in vivo models, allowing to recreate an in vivo-like microenvironment in cancer research. ToC use microfluidics to provide fine-tune control over environmental factors, high-throughput screening, and reduce requirements of samples and reagents. However, creating these microfluidic devices requires skilled researchers and dedicated manufacturing equipment, making widespread adoption cumbersome and difficult. To address some bottlenecks and improve accessibility to ToC technology, innovative materials and fabrication processes are required. Polystyrene (PS) is a promising material for microfluidics due to its biocompatibility, affordability, and optical transparency. Herein, a fabrication process based on direct laser writing on thermosensitive PS, allowing the swift and economical crafting of devices with easy pattern alterations, is presented. For the first time, a device for cell culture fabricated only by PS is presented, allowing customizing and optimization for efficient cell culture approaches. These biochips support 2D and 3D cultures with comparable viability and proliferation kinetics to traditional 96-well plates. The data show that gene and protein silencing efficiencies remain consistent across both chip and plate-based cultures, either 2D culture or 3D spheroid format. Although simple, this approach might facilitate the use of customized chip-based cancer models.

Choroba, K, Zowiślok B, Kula S, Machura B, Maroń {AM }, Erfurt K, Marques C, Cordeiro S, Baptista {PV}, Fernandes {AR}.  2024.  Optimization of Antiproliferative Properties of Triimine Copper(II) Complexes. Journal Of Medicinal Chemistry. 67:19475–19502., Number 21: ACS - American Chemical Society Abstract

Cu(II) complexes with 2,2′:6′,2″-terpyridines (terpy) and 2,6-bis(thiazol-2-yl)pyridines (dtpy) with 1- or 2-naphtyl and methoxy-naphtyl were synthesized to elucidate the impact of the triimine core, naphtyl linking mode, and presence of methoxy groups on the antiproliferative activity of [CuCl2(Ln)]. Their antiproliferative effect was analyzed in ovarian (A2780) and colorectal (HCT116) carcinomas and colorectal carcinoma resistant to doxorubicin (HCT116-DoxR) cell lines and in normal human fibroblasts. Among all complexes, the 1- and 2-naphtyl substituted terpy Cu(II) complexes (Cu1a and Cu1b) showed the strongest cytotoxicity, namely, in HCT116-DoxR 2Dcells and were also capable of inducing the loss of cell viability in 3D HCT116-DoxR spheroids. Their intracellular localization, capability to increase reactive oxygen species (ROS), and interaction with DNA (nonintercalative mode) trigger oxidative DNA cleavage leading to cell death by apoptosis and autophagy. Cu1a and Cu1b do not show in vivo toxicity in a chicken embryo and can interact with bovine serum albumin (BSA).

{Franco Machado}, J, Cordeiro S, Duarte {JN }, Costa {PJ }, Mendes {PJ }, Garcia {MH}, Baptista {PV}, Fernandes {AR}, Morais {TS }.  2024.  Exploiting Co(III)-Cyclopentadienyl Complexes To Develop Anticancer Agents, apr. Inorganic Chemistry. 63:5783–5804., Number 13: ACS - American Chemical Society Abstract

In recent years, organometallic complexes have attracted much attention as anticancer therapeutics aiming at overcoming the limitations of platinum drugs that are currently marketed. Still, the development of half-sandwich organometallic cobalt complexes remains scarcely explored. Four new cobalt(III)-cyclopentadienyl complexes containing N,N-heteroaromatic bidentate, and phosphane ligands were synthesized and fully characterized by elemental analysis, spectroscopic techniques, and DFT methods. The cytotoxicity of all complexes was determined in vitro by the MTS assay in colorectal (HCT116), ovarian (A2780), and breast (MDA-MB-231 and MCF-7) human cancer cell lines and in a healthy human cell line (fibroblasts). The complexes showed high cytotoxicity in cancer cell lines, mostly due to ROS production, apoptosis, autophagy induction, and disruption of the mitochondrial membrane. Also, these complexes were shown to be nontoxic in vivo in an ex ovo chick embryo yolk sac membrane (YSM) assay.

Reigosa-Chamorro, F, Cordeiro S, Pereira T}{M, Filipe B, Baptista {PV}, Fernandes {AR}, Vila {JM }.  2024.  Effect of mono- and dinuclear thiosemicarbazone platinacycles in the proliferation of a colorectal carcinoma cell line. Dalton Transactions. : RSC - Royal Society of Chemistry Abstract

Herein, we describe the synthesis and characterization of a series of thiosemicarbazone platinacycles. Their activity towards HCT116 and A2780 cancer cell lines as well as normal fibroblasts was explored and conclusions about the influence of their structures were drawn based on the results. Ligands L1-3, tetranuclear compounds [Pt(L1-3)]4, [Pt(L1-3)(PPh3)], and [Pt(L1-L3)2{Ph2P(CH2)4PPh2}], and phosphine derivatives, were deemed unpromising owing to their lack of activity. However, mono-coordinated diphosphine complexes [Pt(L1-L3)(Ph2PCH2PPh2-P)] showed high selectivity and low IC50 values, and their antiproliferative activity was further studied. The three studied derivatives 3a, 3b and 3c showed a fast internalization of HCT116 colorectal cancer cells with similar IC50 values, which induced a depolarization of mitochondrial membrane potential, with the subsequent triggering of apoptosis and autophagy in the case of 3c. In the case of compounds 3a and 3b, cell death mechanisms (extrinsic and intrinsic apoptosis, respectively) were triggered via the induction of reactive oxygen species (ROS). The three compounds were not toxic to a chicken embryo in vivo (after 48 h), and, importantly, showed an anti-angiogenic potential after exposure to the IC50 of compounds 3a, 3b and 3c.

Oliveira, BB, Fernandes AR, Baptista PV.  2024.  Shrinking Cancer Research Barriers: Crafting Accessible Tumor-on-Chip Device for Gene Silencing Assays, nov. Advanced Engineering Materials. : John Wiley & Sons, Ltd. Abstract

Tumor-on-chip (ToC) is crucial to bridge the gap between traditional cell culture experiments and in vivo models, allowing to recreate an in vivo-like microenvironment in cancer research. ToC use microfluidics to provide fine-tune control over environmental factors, high-throughput screening, and reduce requirements of samples and reagents. However, creating these microfluidic devices requires skilled researchers and dedicated manufacturing equipment, making widespread adoption cumbersome and difficult. To address some bottlenecks and improve accessibility to ToC technology, innovative materials and fabrication processes are required. Polystyrene (PS) is a promising material for microfluidics due to its biocompatibility, affordability, and optical transparency. Herein, a fabrication process based on direct laser writing on thermosensitive PS, allowing the swift and economical crafting of devices with easy pattern alterations, is presented. For the first time, a device for cell culture fabricated only by PS is presented, allowing customizing and optimization for efficient cell culture approaches. These biochips support 2D and 3D cultures with comparable viability and proliferation kinetics to traditional 96-well plates. The data show that gene and protein silencing efficiencies remain consistent across both chip and plate-based cultures, either 2D culture or 3D spheroid format. Although simple, this approach might facilitate the use of customized chip-based cancer models.

Esmear, T, Twilley D, Thipe {VC}, Katti {KV }, Mandiwana V, Kalombo {ML}, Ray {SS}, Rikhotso-Mbungela R, Bovilla {VR}, Madhunapantula {SR}, Langhanshova L, Roma-Rodrigues C, Fernandes {AR}, Baptista P, Hlati S, Pretorius J, Lall N.  2024.  Anti-inflammatory and antiproliferative activity of Helichrysum odoratissimum sweet. Against lung cancer. South African Journal of Botany. 166:525–538.: Elsevier Abstract

Lung cancer remains the top killing cancer worldwide despite advances in treatment. Seven ethanolic plant extracts were selected and evaluated for their antiproliferative activity against the two main types of lung cancers: non-small cell (A549) and small cell lung cancer cells (SHP-77). An ethanolic extract of Helichrysum odoratissimum Sweet (HO) showed significant antiproliferative activity against lung cancer, with a fifty percent inhibitory concentration (IC50) of 83.43 ± 1.60 µg/mL (A549), 49.46 ± 0.48 µg/mL (SHP-77) and 50.71 ± 2.27 µg/mL, against normal lung epithelial cells (MRC-5), resulting in a selectivity index (SI) value of 0.61 on A549 cells and 1.03 on SHP-77 cells, which was compared to the positive drug control, actinomycin D where the SI values were found to be 2 and 0.25 against A549 and SHP-77 cells, respectively. Against murine macrophages (RAW 264.7) and hepatocytes (HepG2), the HO ethanolic extract showed IC50 values of 60.15 ± 1.98 µg/mL and 23.61 ± 1.06 µg/mL, respectively. Microscopy showed that the HO ethanolic extract induced apoptosis in the A549 and HepG2 cells at 50 µg/mL and 300 µg/mL, respectively. The HO ethanolic extract, furthermore, inhibited the pro-inflammatory enzymes, cyclooxygenase 2 (COX-2) and 5-lipoxygenase (5-LOX) with IC50 values of 7.94 ± 3.84 µg/mL and 2.08 ± 1.35 µg/mL, respectively, whereas the positive controls Ibuprofen (COX-2) and Zileuton (5-LOX) showed IC50 values of 0.85 ± 0.14 µg/mL and 0.06 ± 0.05 µg/mL, respectively. The activity of NAD(P)H quinone oxidoreductase-1 (NQO1), which is a direct target of nuclear factor erythroid-2-related factor-2 (NRF2), was significantly inhibited in the A549 cells by the HO ethanolic extract (at 125 µg/mL) when compared to the positive control, brusatol (at 500 nM). Using the ex ovo yolk sac membrane (YSM) assay, the HO ethanolic extract (at 18.5 µg/egg) showed a 31.65 ± 12.80% inhibition of blood vessel formation. This is the first report of the noteworthy antiproliferative activity of the HO ethanolic extract on lung cancer cells including its potential to target several enzymes associated with inflammation and therefore, should be considered for further analysis.

Idiago-López, J, Ferreira D, Asín L, Moros M, Armenia I, Grazú V, Fernandes {AR}, {de la Fuente} {JM }, Baptista {PV}, Fratila {RM }.  2024.  Membrane-localized magnetic hyperthermia promotes intracellular delivery of cell-impermeant probes, aug. Nanoscale. 16:15176–15195., Number 32: RSC - Royal Society of Chemistry Abstract

In this work, we report the disruptive use of membrane-localized magnetic hyperthermia to promote the internalization of cell-impermeant probes. Under an alternating magnetic field, magnetic nanoparticles (MNPs) immobilized on the cell membrane via bioorthogonal click chemistry act as nanoheaters and lead to the thermal disruption of the plasma membrane, which can be used for internalization of different types of molecules, such as small fluorescent probes and nucleic acids. Noteworthily, no cell death, oxidative stress and alterations of the cell cycle are detected after the thermal stimulus, although cells are able to sense and respond to the thermal stimulus through the expression of different types of heat shock proteins (HSPs). Finally, we demonstrate the utility of this approach for the transfection of cells with a small interference RNA (siRNA), revealing a similar efficacy to a standard transfection method based on the use of cationic lipid-based reagents (such as Lipofectamine), but with lower cell toxicity. These results open the possibility of developing new procedures for “opening and closing” cellular membranes with minimal disturbance of cellular integrity. This on-demand modification of cell membrane permeability could allow the direct intracellular delivery of biologically relevant (bio)molecules, drugs and nanomaterials, thus overcoming traditional endocytosis pathways and avoiding endosomal entrapment.

Choroba, K, Zowiślok B, Kula S, Machura B, Maroń {AM }, Erfurt K, Marques C, Cordeiro S, Baptista {PV}, Fernandes {AR}.  2024.  Optimization of Antiproliferative Properties of Triimine Copper(II) Complexes, nov. Journal Of Medicinal Chemistry. : ACS - American Chemical Society Abstract

Cu(II) complexes with 2,2':6',2″-terpyridines (terpy) and 2,6-bis(thiazol-2-yl)pyridines (dtpy) with 1- or 2-naphtyl and methoxy-naphtyl were synthesized to elucidate the impact of the triimine core, naphtyl linking mode, and presence of methoxy groups on the antiproliferative activity of [CuCl 2(L n )]. Their antiproliferative effect was analyzed in ovarian (A2780) and colorectal (HCT116) carcinomas and colorectal carcinoma resistant to doxorubicin (HCT116-DoxR) cell lines and in normal human fibroblasts. Among all complexes, the 1- and 2-naphtyl substituted terpy Cu(II) complexes ( Cu1a and Cu1b) showed the strongest cytotoxicity, namely, in HCT116-DoxR 2Dcells and were also capable of inducing the loss of cell viability in 3D HCT116-DoxR spheroids. Their intracellular localization, capability to increase reactive oxygen species (ROS), and interaction with DNA (nonintercalative mode) trigger oxidative DNA cleavage leading to cell death by apoptosis and autophagy. Cu1a and Cu1b do not show in vivo toxicity in a chicken embryo and can interact with bovine serum albumin (BSA).

Abdulmawjood, B, Roma-Rodrigues C, Baptista {PV}, Fernandes {AR}.  2024.  Tackling Imatinib Resistance via Au-nanoconjugates using A Cml Resistant Cell Line. Particle and Particle Systems Characterization. 41, Number 1: Wiley-VCH Verlag Abstract

Chronic myeloid leukemia (CML) is a rare malignant proliferative hematopoietic disease due to overexpression of a tyrosine kinase (TK) derived from the breakpoint cluster region (BCR)-abelson tyrosine-protein kinase 1 (ABL1) gene fusion. Imatinib (IM), blocks this tyrosine kinase, and is the first line TK inhibitor (TKI) used in CML treatment. In a high percentage of CML patients, a poor response with relapse and disease progression is associated to acquisition of resistance through different mechanisms, including dysregulation of c-MYC proto-oncogene. Gold nanoparticles (AuNPs) are shown to allow improved efficacy in gene silencing approaches toward cancer therapy. Herein, the silencing potential of AuNPs functionalized with antisense oligonucleotides selectively targeting the e14a2 BCR-ABL1 or the c-MYC, alone and combination is evaluated. It is demonstrated efficient silencing of gene expression that translated to a downregulation of protein levels in IM resistant CML cells (K562-IM). This combination allowed for increased death of the malignant cells. These Au-nanoconjugates may be useful to tackle IM-resistance mechanisms, providing an additional tool for future combinatory schemes to fight CML with imatinib resistance.

Moreira, D, Alexandre D, Miranda A, c}o PL{\c, Baptista {PV}, Tomaz C, Lu Y, Cruz C.  2024.  Detecting mir-155-3p through a Molecular Beacon Bead-Based Assay. Molecules. 29, Number 13: MDPI - Multidisciplinary Digital Publishing Institute Abstract

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.

Choroba, K, Zowislok B, Kula S, Machura B, Maron AM, Erfurt K, Cordeiro S, Baptista PV, Fernandes {AR}.  2024.  Optimization of Antiproliferative Properties of Triimine Copper(II) Complexes, nov. Journal Of Medicinal Chemistry. 67:19475–19502., Number 21: ACS - American Chemical Society Abstract

Cu(II) complexes with 2,2′:6′,2″-terpyridines (terpy) and 2,6-bis(thiazol-2-yl)pyridines (dtpy) with 1- or 2-naphtyl and methoxy-naphtyl were synthesized to elucidate the impact of the triimine core, naphtyl linking mode, and presence of methoxy groups on the antiproliferative activity of [CuCl2(Ln)]. Their antiproliferative effect was analyzed in ovarian (A2780) and colorectal (HCT116) carcinomas and colorectal carcinoma resistant to doxorubicin (HCT116-DoxR) cell lines and in normal human fibroblasts. Among all complexes, the 1- and 2-naphtyl substituted terpy Cu(II) complexes (Cu1a and Cu1b) showed the strongest cytotoxicity, namely, in HCT116-DoxR 2Dcells and were also capable of inducing the loss of cell viability in 3D HCT116-DoxR spheroids. Their intracellular localization, capability to increase reactive oxygen species (ROS), and interaction with DNA (nonintercalative mode) trigger oxidative DNA cleavage leading to cell death by apoptosis and autophagy. Cu1a and Cu1b do not show in vivo toxicity in a chicken embryo and can interact with bovine serum albumin (BSA).

Oliveira, {BB }, Fernandes {AR}, Baptista {PV}.  2024.  Assessing the gene silencing potential of AuNP-based approaches on conventional 2D cell culture versus 3D tumor spheroid. Frontiers in Bioengineering and Biotechnology. 12: Frontiers Media Abstract

Three-dimensional (3D) cell culture using tumor spheroids provides a crucial platform for replicating tissue microenvironments. However, effective gene modulation via nanoparticle-based transfection remains a challenge, often facing delivery hurdles. Gold nanoparticles (AuNPs) with their tailored synthesis and biocompatibility, have shown promising results in two-dimensional (2D) cultures, nevertheless, they still require a comprehensive evaluation before they can reach its full potential on 3D models. While 2D cultures offer simplicity and affordability, they lack physiological fidelity. In contrast, 3D spheroids better capture in vivo conditions, enabling the study of cell interactions and nutrient distribution. These models are essential for investigating cancer behavior, drug responses, and developmental processes. Nevertheless, transitioning from 2D to 3D models demands an understanding of altered internalization mechanisms and microenvironmental influences. This study assessed ASO-AuNP conjugates for silencing the c-MYC oncogene in 2D cultures and 3D tumor spheroids, revealing distinctions in gene silencing efficiency and highlighting the microenvironment’s impact on AuNP-mediated gene modulation. Herein, we demonstrate that increasing the number of AuNPs per cell by 2.6 times, when transitioning from a 2D cell model to a 3D spheroid, allows to attain similar silencing efficiencies. Such insights advance the development of targeted gene therapies within intricate tissue-like contexts.

Alexandre, D, Fernandes {AR}, Baptista {PV}, Cruz C.  2024.  Evaluation of miR-155 silencing using a molecular beacon in human lung adenocarcinoma cell line, jul. Talanta. 274: Elsevier Abstract

Lung cancer (LC) is a leading cause of global cancer-related deaths, highlighting the development of innovative methods for biomarker detection improving the early diagnostics. microRNAs (miRs) alterations are known to be involved in the initiation and progression of human cancers and can act as biomarkers for diagnostics and treatment. Herein, we develop the application of molecular beacon (MB) technology to monitor miR-155-3p expression in human lung adenocarcinoma A549 cells without complementary DNA synthesis, amplification, or expensive reagents. Furthermore, we produced gold nanoparticles (AuNPs) for delivering antisense oligonucleotides into A549 cells to reduce miR-155-3p expression, which was subsequently detectable using the MB. The MB was designed and structural characterized by Förster Resonance Energy Transfer (FRET)-melting, Circular Dichroism (CD), Nuclear magnetic resonance (NMR), and fluorometric experiments, and then the hybridization conditions were optimized for an in vitro approach involving the detection of miR-155-3p in total RNA extracted from A549 cell line. The expression profile of miR-155-3p was obtained by RT-qPCR. The results demonstrated that MB was properly designed and showed efficacy in targeting miR-155-3p. Furthermore, a limit of detection down to nanomolar concentration was achieved and the specificity of the biosensor was proved. Moreover, the self-assembly of ASOs with AuNPs exhibited exceptional target specificity, effectively silencing miR-155-3p. Notably, compared to lipid-based transfection agent, AuNPs displayed superior silencing efficiency. We highlighted the ability of MB to detect changes in the target gene expression after gene silencing. Overall, this innovative approach represents a promising tool for detecting various biomarkers at the same time, with potential applications in clinical settings.

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