Effects of ionizing radiation and HPSE1 inhibition on the invasion of oral tongue carcinoma cells on human extracellular matrices in vitro.

Chemoradiation is an established approach in the treatment of advanced oral tongue squamous cell carcinoma (OTSCC), but therapy may cause severe side-effects due to signal interchanges between carcinoma and the tumour microenvironment (TME). In this study, we examined the potential use of our human 3D myoma disc and Myogel models in in vitro chemoradiation studies by analysing the effects of ionizing radiation (IR) and the combined effect of heparanase I (HPSE1) inhibitors and IR on OTSCC cell proliferation, invasion and MMP-2 and - 9 production. Finally, we analysed the long-term effects of IR by studying clones of previously irradiated and invaded HSC-3 cells. We found that in both human uterine leiomyoma-based extracellular matrix models IR inhibited the invasion of HSC-3 cells, but blocking HPSE1 activity combined with IR induced their invasion. Low doses of IR increased MMP expression and initiated epithelial-mesenchymal transition in cells cultured on myoma discs. We conclude that myoma models offer consistent methods for testing human carcinoma cell invasion and phenotypic changes during chemoradiation treatment. In addition, we showed that IR had long-term effects on MMP-2 and - 9, which might elicit different HSC-3 invasion responses when cells were under the challenge of HPSE1 inhibitors and IR.

Aptamer delivery of siRNA, radiopharmaceutics and chemotherapy agents in cancer.

Aptamers are oligonucleotide reagents with high affinity and specificity, which among other therapeutic and diagnostic applications have the capability of acting as delivery agents. Thus, aptamers are capable of carrying small molecules, nanoparticles, radiopharmaceuticals or fluorescent agents as well as nucleic acid therapeutics specifically to their target cells. In most cases, the molecules may possess interesting therapeutic properties, but their lack of specificity for a particular cell type, or ability to internalise in such a cell, hinders their clinical development, or cause unwanted side effects. Thus, chemotherapy or radiotherapy agents, famous for their side effects, can be coupled to aptamers for specific delivery. Equally, siRNA have great therapeutic potential and specificity, but one of their shortcomings remain the delivery and internalisation into cells. Various methodologies have been proposed to date, including aptamers, to resolve this problem. Therapeutic or imaging reagents benefit from the adaptability and ease of chemical manipulation of aptamers, their high affinity for the specific marker of a cell type, and their internalisation ability via cell mediated endocytosis. In this review paper, we explore the potential of the aptamers as delivery agents and offer an update on current status and latest advancements.

Cellular inactivation induced by H2O2 and active oxygen species generated by environmental stresses in bacteria

Oxyygen free radicals are highly reactive species that damage several cellular macromolecules and organelles, including membrane lipid peroxidation and produce DNA lesions. We have discussed here; i) The mechanism of radiation-induced cellular damage in bacteria through the intermediation of active oxygen species; ii) the cellular inactivation and the role of bacterial SOS and OxyR systems in the repair of lesions induced by H2O2 under low iron condition; iii) the lethal interaction between H2O2 and o-phenanthroline in E. coli; iv) the biological response induced by near-UV radiation mediated by active oxygen species and finally v) the mutagenic potential of popular plant extracts like guaraná (Paullinia cupana), mate (Ilex paraguariensis) and saiao (Kalanchoe brasiliensis), whose effects are eventually mediated by active oxygen species.