A combined microRNA-based targeted therapeutic approach to eradicate glioblastoma stem-like cells

A minor population of glioblastoma stem-like cells (GSCs) has been implicated in the relapse and resistance of glioblastoma to therapeutic treatments. Based on knowledge of the involvement of multiple microRNAs in GSC propagation, we designed a combinational approach to target the GSC population with multiple miRNA-based therapeutics. As carriers for the targeted delivery we took advantage of two aptamers that bind to, and inhibit, the receptor tyrosine kinases, Axl and PDGFRβ. We showed that the aptamer conjugates are transported through an in vitro blood-brain barrier (BBB) model. Furthermore, combining miR-137 and antimiR-10b synergizes with the receptor inhibitory function of aptamer carriers and prevents GSC expansion. Results highlighted the potential of combining multifunctional RNA-based therapeutics for selective targeting of GSCs and offer a proof of principle strategy to potentially fulfill the still unmet need for effective and safe treatment of glioma

Bubaline milk with a high content of trans fatty acids increased cholesterolemia and tended to aggravate atherosclerosis in rabbits

Búfalas suplementadas con una mezcla de aceites de girasol + pescado pueden reducir en la leche los niveles de ácidos grasos saturados (AGS), considerados hipercolesterolémicos y pro-aterogénicos, e incrementar los ácidos grasos trans-11 18:1 y cis-9,trans-11 18:2, con propiedades anti-aterogénicas. Este trabajo comparó los efectos del consumo de dos leches bubalinas, con baja y alta relación de ácidos grasos trans (AGt)/AGS, sobre el lipidograma y el desarrollo de ateroesclerosis inducidos por colesterol en conejos. Veinte conejos neozelandeses, machos, fueron aleatoriamente separados en un grupo control (n=10) que recibió leche con baja relación AGt/AGS (5,3% de AGt y 67,12% de AGS) obtenida de búfalas en sistema pastoril; y un grupo alto trans (n=10) que recibió leche con alta relación AGt/AGS (25,84% de AGt y 45,89% de AGS) obtenida de búfalas con suplementación lipídica en su dieta. La experiencia duró 75 días y, a partir del día 15, todos los conejos fueron desafiados con 0,93 g de colesterol/día, vía oral, a fin de inducir lesiones ateroescleróticas. Los conejos consumieron de manera voluntaria 9293,13 ml y 9930 ml de leche con baja y alta relación AGt/AGS, respectivamente (p 0,404). Los conejos que consumieron leche con alta relación AGt/AGS registraron un leve incremento significativo (p 0,049) del colesterol total (6,08 g/l), cuando se comparó con el grupo control (5,58 g/l). No se detectaron diferencias entre grupos en el colesterol LDL (p 0,073), colesterol HDL (p 0,078) y triglicéridos (p 0,174). Las lesiones ateroescleróticas fueron más extensas en los conejos que consumieron leche con alta relación AGt/AGS, aunque sin significación estadística (p>0,05) cuando se comparó el control. En conclusión, la leche bubalina obtenida con la suplementación lipídica referida en este estudio, incrementó la colesterolemia y tendió a agravar la ateroesclerosis en conejos. Dichos efectos, posiblemente estén relacionados con el alto contenido de AGt de esta leche.Bubaline milk with a high content of trans fatty acids increased cholesterolemia and tended to aggravate atherosclerosis in rabbits. Rev. Vet. 30: 1, 32-38, 2019. Buffalo heifers supplemented with a mixture of sunflower oil + fish can produce milk with low level saturated fatty acids (SFA, which are considered hypercholesterolemic and pro-atherogenic), and increase the synthesis of trans-11 18: 1 and cis-9, trans-11 18: 2 fatty acids (with anti-atherogenic properties). This work compared the effects of the administration to rabbits of two bubaline milk, with low and high trans/saturated fatty acids (tFA/SFA) ratio, on the development of atherosclerosis induced by cholesterol. Twenty New Zealand rabbits, males, were randomly separated into a control group (n=10) that received milk with low tFA/SFA ratio (5.3% tFA and 67.12% SFA) obtained from grazing buffalos; and a high trans group (n = 10) that received milk with high tFA/SFA ratio (25.84% tFA and 45.89% SFA) obtained from buffalos with lipid supplementation in their diet. The experience lasted 75 days and, from day 15, all rabbits were challenged with 0.93 g of cholesterol/day orally, to induce atherosclerotic lesions. The rabbits voluntarily consumed 9293.13 ml and 9930 ml of milk with low and high tFA/SFA ratio, respectively (p 0.404). Rabbits that consumed milk with a high tFA/SFA ratio increased (p 0.049) serum levels of total cholesterol (6.08 g/l), compared to the control group (5.58 g/l). No differences were detected between groups in LDL cholesterol (p 0.073), HDL cholesterol (p 0.078) and triglycerides (p 0.174). Atherosclerotic lesions were more extensive in rabbits that consumed milk with a high tFA/SFA ratio, although without statistical significance (p> 0.05) compared to rabbits that consumed milk with low tFA/SFA ratio. In conclusion, bubaline milk obtained from animals with lipid supplementation contributed to increase cholesterolemia and tended to worsen atherosclerosis in rabbits. These effects may be related to the high content of tFA of this milk.Fil: Lertora, Walter Javier. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Villordo, Gabriela Ines. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Mussart, Norma Beatriz. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Clinica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Catuogno, María Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Sanchez Negrette, Marcial. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentin

MiR-34c may protect lung cancer cells from paclitaxel-induced apoptosis

MicroRNAs (miRNAs) constitute a class of small non-coding RNAs that negatively regulate gene expression at post-transcriptional level in a sequence specific manner. They are involved in many biological processes, including cell proliferation, apoptosis and differentiation, and are considered as promising new therapeutic targets for cancer. However, the identity of miRNAs involved in apoptosis and their respective targets remain largely unknown. Given the elevated complexity of miRNA regulation of gene expression, we performed a functional screening as an alternative strategy to identify those miRNAs that in lung cancer cells may interfere with the apoptotic process. To this aim we generated a derivative of the non-small cell lung carcinoma A549 cell line in which caspase-8, a critical upstream initiator of apoptosis, can be activated by the administration of the small dimerizer drug AP20187. We found a number of miRNAs that may rescue cell viability from caspase-8 activation. They included miRNAs already described as oncogenic such as miR-17, miR-135, miR-520, but also some miRNAs such as miR-124-1 and miR-34c for which a tumor suppressive role has been instead described or expected. Among them, miR-34c-5p markedly increased resistance to paclitaxel induced apoptosis. We demonstrate that Bmf (Bcl-2 modifying factor) is a target of miR-34c-5p and that its silencing, together with that of c-myc, a known target of miR-34c-5p, contributes to resistance to apoptosis induced by paclitaxel via p53 downregulation

Aptamer-Mediated Targeted Delivery of Therapeutics: An Update

The selective delivery of drugs in a cell- or tissue-specific manner represents the main challenge for medical research; in order to reduce the occurrence of unwanted off-target effects. In this regard, nucleic acid aptamers have emerged as an attractive class of carrier molecules due to their ability to bind with high affinity to specific ligands; their high chemical flexibility; as well as tissue penetration capability. To date, different aptamer-drug systems and aptamer–nanoparticles systems, in which nanoparticles function together with aptamers for the targeted delivery, have been successfully developed for a wide range of therapeutics, including toxins; peptides; chemotherapeutics and oligonucleotides. Therefore, aptamer-mediated drug delivery represents a powerful tool for the safe and effective treatment of different human pathologies, including cancer; neurological diseases; immunological diseases and so on. In this review, we will summarize recent progress in the field of aptamer-mediated drug delivery and we will discuss the advantages, the achieved objectives and the challenges to be still addressed in the near future, in order to improve the effectiveness of therapies

Aptamer Cell-Based Selection: Overview and Advances

Aptamers are high affinity single-stranded DNA/RNA molecules, produced by a combinatorial procedure named SELEX (Systematic Evolution of Ligands by Exponential enrichment), that are emerging as promising diagnostic and therapeutic tools. Among selection strategies, procedures using living cells as complex targets (referred as “cell-SELEX”) have been developed as an effective mean to generate aptamers for heavily modified cell surface proteins, assuring the binding of the target in its native conformation. Here we give an up-to-date overview on cell-SELEX technology, discussing the most recent advances with a particular focus on cancer cell targeting. Examples of the different protocol applications and post-SELEX strategies will be briefly outlined

Aptamer-Mediated Targeted Delivery of Therapeutics: An Update

The selective delivery of drugs in a cell- or tissue-specific manner represents the main challenge for medical research; in order to reduce the occurrence of unwanted off-target effects. In this regard, nucleic acid aptamers have emerged as an attractive class of carrier molecules due to their ability to bind with high affinity to specific ligands; their high chemical flexibility; as well as tissue penetration capability. To date, different aptamer-drug systems and aptamer–nanoparticles systems, in which nanoparticles function together with aptamers for the targeted delivery, have been successfully developed for a wide range of therapeutics, including toxins; peptides; chemotherapeutics and oligonucleotides. Therefore, aptamer-mediated drug delivery represents a powerful tool for the safe and effective treatment of different human pathologies, including cancer; neurological diseases; immunological diseases and so on. In this review, we will summarize recent progress in the field of aptamer-mediated drug delivery and we will discuss the advantages, the achieved objectives and the challenges to be still addressed in the near future, in order to improve the effectiveness of therapies

Nucleic Acid Aptamers Targeting Epigenetic Regulators: An Innovative Therapeutic Option

Epigenetic mechanisms include DNA methylation, posttranslational modifications of histones, chromatin remodeling factors, and post transcriptional gene regulation by noncoding RNAs. All together, these processes regulate gene expression by changing chromatin organization and DNA accessibility. Targeting enzymatic regulators responsible for DNA and chromatin modifications hold promise for modulating the transcriptional regulation of genes that are involved in cancer, as well as in chronic noncommunicable metabolic diseases like obesity, diabetes, and cardiovascular diseases. Increasingly studies are emerging, leading to the identification of specific and effective molecules targeting epigenetic pathways involved in disease onset. In this regard, RNA interference, which uses small RNAs to reduce gene expression and nucleic acid aptamers are arising as very promising candidates in therapeutic approach. Common to all these strategies is the imperative challenge of specificity. In this regard, nucleic acid aptamers have emerged as an attractive class of carrier molecules due to their ability to bind with high affinity to specific ligands, their high chemical flexibility as well as tissue penetration capability. In this review, we will focus on the recent progress in the field of aptamers used as targeting moieties able to recognize and revert epigenetics marks involved in diseases onset

STAT3 Gene Silencing by Aptamer-siRNA Chimera as Selective Therapeutic for Glioblastoma

Glioblastoma (GBM) is the most frequent and aggressive primary brain tumor in adults, and despite advances in neuro-oncology, the prognosis for patients remains dismal. The signal transducer and activator of transcription-3 (STAT3) has been reported as a key regulator of the highly aggressive mesenchymal GBM subtype, and its direct silencing (by RNAi oligonucleotides) has revealed a great potential as an anti-cancer therapy. However, clinical use of oligonucleotide-based therapies is dependent on safer ways for tissue-specific targeting and increased membrane penetration. The objective of this study is to explore the use of nucleic acid aptamers as carriers to specifically drive a STAT3 siRNA to GBM cells in a receptor-dependent manner. Using an aptamer that binds to and antagonizes the oncogenic receptor tyrosine kinase PDGFRβ (Gint4.T), here we describe the design of a novel aptamer-siRNA chimera (Gint4.T-STAT3) to target STAT3. We demonstrate the efficient delivery and silencing of STAT3 in PDGFRβ+GBM cells. Importantly, the conjugate reduces cell viability and migration in vitro and inhibits tumor growth and angiogenesis in vivo in a subcutaneous xenograft mouse model. Our data reveals Gint4.T-STAT3 conjugate as a novel molecule with great translational potential for GBM therapy.Glioblastoma (GBM) is the most frequent and aggressive primary brain tumor in adults, and despite advances in neuro-oncology, the prognosis for patients remains dismal. The signal transducer and activator of transcription-3 (STAT3) has been reported as a key regulator of the highly aggressive mesenchymal GBM subtype, and its direct silencing (by RNAi oligonucleotides) has revealed a great potential as an anti-cancer therapy. However, clinical use of oligonucleotide-based therapies is dependent on safer ways for tissue-specific targeting and increased membrane penetration. The objective of this study is to explore the use of nucleic acid aptamers as carriers to specifically drive a STAT3 siRNA to GBM cells in a receptor-dependent manner. Using an aptamer that binds to and antagonizes the oncogenic receptor tyrosine kinase PDGFRβ (Gint4.T), here we describe the design of a novel aptamer-siRNA chimera (Gint4.T-STAT3) to target STAT3. We demonstrate the efficient delivery and silencing of STAT3 in PDGFRβ+ GBM cells. Importantly, the conjugate reduces cell viability and migration in vitro and inhibits tumor growth and angiogenesis in vivo in a subcutaneous xenograft mouse model. Our data reveals Gint4.T-STAT3 conjugate as a novel molecule with great translational potential for GBM therapy

Aptamer chimeras for therapeutic delivery: The challenging perspectives

Nucleic acid-based aptamers have emerged as efficient delivery carriers of therapeutics. Thanks to their unique features, they can be, to date, considered one of the best targeting moieties, allowing the specific recognition of diseased cells and avoiding unwanted off-target effects on healthy tissues. In this review, we revise the most recent contributes on bispecific and multifunctional aptamer therapeutic chimeras. We will discuss key examples of aptamer-mediated delivery of nucleic acid and peptide-based therapeutics underlying their great potentiality and versatility. Achieved objectives and challenges will be highlighted as well