Anti-Heparanase Aptamers as Potential Diagnostic and Therapeutic Agents for Oral Cancer

Abstract

Heparanase is an endoglycosidase enzyme present in activated leucocytes, mast cells, placental tissue, neutrophils and macrophages, and is involved in tumour metastasis and tissue invasion. It presents a potential target for cancer therapies and various molecules have been developed in an attempt to inhibit the enzymatic action of heparanase. In an attempt to develop a novel therapeutic with an associated diagnostic assay, we have previously described high affinity aptamers selected against heparanase. In this work, we demonstrated that these anti-heparanase aptamers are capable of inhibiting tissue invasion of tumour cells associated with oral cancer and verified that such inhibition is due to inhibition of the enzyme and not due to other potentially cytotoxic effects of the aptamers. Furthermore, we have identified a short 30 bases aptamer as a potential candidate for further studies, as this showed a higher ability to inhibit tissue invasion than its longer counterpart, as well as a reduced potential for complex formation with other non-specific serum proteins. Finally, the aptamer was found to be stable and therefore suitable for use in human models, as it showed no degradation in the presence of human serum, making it a potential candidate for both diagnostic and therapeutic use.

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

“…Treatment with anti-HPSE1 and 1.5 M short protected aptamer significantly decreased the invasion area and invasion depth compared with untreated non-irradiated myomas. This is in accordance with our previous data showing the effect of these heparanase inhibitors on invasion [25]. Invasion depth of aptamertreated cells decreased with an irradiation dose of 2 Gy compared with treated non-irradiated cells.…”

“…The treatments alone showed varying degrees of effectiveness. The anti-HPSE1 and short protected aptamer against HPSE1 alone showed minimal effect, in accordance with previously published data [25], whereas Erbitux alone had a diminishing effect of > 50% of clonogenic viability, however this was not statistically significant. Irradiation alone reduced the cell survival in a dose-dependent increasing manner, as expected.…”

“…We have introduced a human 3D myoma organotypic disc model [12,15] for in vitro invasion experiments. Previously, we showed that anti-heparanase aptamers inhibited the invasion of a highly aggressive OTSCC cell line, HSC-3, in myoma discs [25]. In this study, we analysed the combined effect of aptamers and ionizing radiation (IR) on HSC-3 cell invasion.…”

“…We recently showed that 1.5 M short heparanase aptamer does not affect cell viability [25]. We wanted to further investigate how this treatment combined with irradiation affects OTSCC cells.…”

“…In this study, we tested the usability and consistency of human TME-mimicking tissue methods for analysing the effects of chemoradiation using commercial OTSCC cell lines. We have previously studied the feasibility of anti-heparanase aptamers as therapeutic agents against OTSCC with myoma discs [25], and now we further explored the effectiveness of these aptamers together with IR in a myoma disc model and in Myogel. We investigated also the effects of anti-heparanase 1 (HPSE1) antibody, which inhibits heparanase activity [26], and cetuximab (Erbitux), an EGFR inhibitor [27].…”