Antibodies have been shown to be a potent therapeutic tool. However, their use for targeting brain diseases, including neurodegenerative diseases and brain cancers, has been limited, particularly because the blood–brain barrier (BBB) makes brain tissue hard to access by conventional antibody-targeting strategies. In this review, we summarize new antibody therapeutic approaches to target brain tumors, especially malignant gliomas, as well as their potential drawbacks. Many different brain delivery platforms for antibodies have been studied such as liposomes, nanoparticle-based systems, cell-penetrating peptides (CPPs), and cell-based approaches. We have already shown the successful delivery of single-chain fragment variable (scFv) with CPP as a linker between two variable domains in the brain. Antibodies normally face poor penetration through the BBB, with some variants sufficiently passing the barrier on their own. A “Trojan horse” method allows passage of biomolecules, such as antibodies, through the BBB by receptor-mediated transcytosis (RMT). Such examples of therapeutic antibodies are the bispecific antibodies where one binding specificity recognizes and binds a BBB receptor, enabling RMT and where a second binding specificity recognizes an antigen as a therapeutic target. On the other hand, cell-based systems such as stem cells (SCs) are a promising delivery system because of their tumor tropism and ability to cross the BBB. Genetically engineered SCs can be used in gene therapy, where they express anti-tumor drugs, including antibodies. Different types and sources of SCs have been studied for the delivery of therapeutics to the brain; both mesenchymal stem cells (MSCs) and neural stem cells (NSCs) show great potential. Following the success in treatment of leukemias and lymphomas, the adoptive T-cell therapies, especially the chimeric antigen receptor-T cells (CAR-Ts), are making their way into glioma treatment as another type of cell-based therapy using the antibody to bind to the specific target(s). Finally, the current clinical trials are reviewed, showing the most recent progress of attractive approaches to deliver therapeutic antibodies across the BBB aiming at the specific antigen.

Circular RNAs (circRNAs) have been shown to play an important role in the pathogenesis of hepatocellular carcinoma (HCC). By implementing available transcriptomic analyses of HCC patients, we identified an upregulated circRNA hsa_circ_0062682. Stable perturbations of hsa_circ_0062682 in Huh-7 and SNU-449 cell lines influenced colony formation, migration, cell proliferation, sorafenib sensitivity, and additionally induced morphological changes in cell lines, indicating an important role of hsa_circ_0062682 in oncogenesis. Pathway enrichment analysis and gene set enrichment analysis of the transcriptome data from hsa_circ_0062682 knockdown explained the observed phenotypes and exposed transcription factors E2F1, Sp1, HIF-1α, and NFκB1 as potential downstream targets. Biotinylated oligonucleotide pulldown combined with proteomic analyses identified protein interaction partners of which YBX1, a known oncogene, was confirmed by RNA immunoprecipitation. Furthermore, we discovered a complex cell-type-specific phenotype in response to the oncogenic potential of hsa_circ_0062682. This finding is in line with different classes of HCC tumours, and more studies are needed to shed a light on the molecular complexity of liver cancer.

Circular RNAs (circRNAs) are increasingly recognized as having a role in cancer development. Their expression is modified in numerous cancers, including hepatocellular carcinoma (HCC); however, little is known about the mechanisms of their regulation. The aim of this study was to identify regulators of circRNAome expression in HCC. Using publicly available datasets, we identified RNA binding proteins (RBPs) with enriched motifs around the splice sites of differentially expressed circRNAs in HCC. We confirmed the binding of some of the candidate RBPs using ChIP-seq and eCLIP datasets in the ENCODE database. Several of the identified RBPs were found to be differentially expressed in HCC and/or correlated with the overall survival of HCC patients. According to our bioinformatics analyses and published evidence, we propose that NONO, PCPB2, PCPB1, ESRP2, and HNRNPK are candidate regulators of circRNA expression in HCC. We confirmed that the knocking down the epithelial splicing regulatory protein 2 (ESRP2), known to be involved in the maintenance of the adult liver phenotype, significantly changed the expression of candidate circRNAs in a model HCC cell line. By understanding the systemic changes in transcriptome splicing, we can identify new proteins involved in the molecular pathways leading to HCC development and progression.

Izhodišča: Cirkadiani ritem se uravnava na centralni in celični ravni preko transkripcijsko-translacijskih povratnih zank, ki so natančno uravnavane. Vpliv na uravnavanje cirkadianega ritma imajo miRNA molekule, ki skupaj s proteinskimi kompleksi privedejo do utišanja prevajanja določenih celičnih proteinov. Kronična motnja v cirkadianem ritmu lahko privede do maligne transformacije celic. Hepatocelularni karcinom je eden najpogostejših vrst raka pri človeku, pri katerem še vedno ni pojasnjen vpliv različnih signalnih poti na karcinogenezo. Namen študije je bil ugotoviti vpliv transkripcijskih dejavnikov cirkadianega ritma in miRNA na izražanje mRNA in krožnih RNA iz istega genskega lokusa, tj. gena LDLR (LDL receptor). Metode: Poskus smo izvedli na celičnih linijah Hep G2 in Huh7. Sprva smo v celice s postopkom transfekcije vnesli želene molekule (hsa-miR-17 in cirkadiane transkripcijske faktorje), s katerimi smo želeli vplivati na izražanje genov, ki so nas zanimali. Iz celic smo nato osamili RNA, ki smo jo nato prepisali v komplementarno DNA in izvedli qPCR (kvantitativno verižno reakcijo s polimerazo), na podlagi katere smo sklepali na raven izražanja želenih genov. Rezultate smo računalniško obdelali in jih grafično predstavili. Rezultati: Z obdelavo rezultatov smo ugotovili, da nobene od treh hipotez nismo uspeli potrditi, saj pri nobenem rezultatu v stopnji izražanja želenih genov nismo ugotovili statistično pomembne razlike (α=0,05). Zaključki: Kljub temu da sprememb v izražanju genov nismo uspeli potrditi, bi bilo raziskovano področje vredno nadaljnjih raziskav, ki bi trdneje prikazale povezavo. Osrediniti bi se morali na konkretne molekule, s čimer bi pridobili nove tarče za zdravljenje jetrnih bolezni, s katerimi bi izboljšali kakovost življenja bolnikov s HCC. Ugotovili bi lahko tudi nove dejavnike tveganja, na podlagi katerih bi lahko bolje ozaveščali prebivalstvo o preventivi, ki bi zmanjšala incidenco HCC.