Carbohydrates-Modified Pt(IV) Pro-Drugs -Conjugated Graphene Oxide as a Novel Therapeutic Strategy to Target Osteosarcoma

<b>INTRODUCTION</b><br/>Osteosarcoma is the most common type of bone cancer diagnosed especially in children and young adults¹. A combination of chemotherapy, radiotherapy and surgery is commonly used to treat this type of cancer^2,3. In detail, chemotherapy is based on the use of molecules targeting the high cancer cell proliferation metabolism such as Platinum (Pt)-based drugs that binds nuclear DNA upon overpassing the cell membrane, causing its damage and the arrest of the cancer cell cycle at G2/M transition phase, leading to apoptosis^4-7. Despite Pt chemotherapeutics are the most potent used anticancer drugs, their side effects (high degradation before entering the cells, the off-target organs toxicity, and cell resistance) remain great drawbacks^8-11.<br/> <br/><b>EXPERIMENTAL METHODS</b><br/>In this study, we synthetized Graphene oxide (GO)-based nanoplatforms as smart delivery systems of Platinum-based drug. In order to reduce GO cytotoxicity in health cells while promoting its cellular uptake in cancer cells, and to allow Pt loading on GO, 8-arm polyethylene glycol-amine (PEG) was used. The bioactivity of GO-PEG-Pt platforms were compared to Pt-free (15 μM, 30 μM, and 60 μM) on three osteosarcoma cell lines (MG63, U2 and SAOS-2). The in vitro analysis of cellular uptake (ICP-OES), viability (MTT assay), morphology (actin and DAPI staining) and migration (scratch test) was performed.<br/> <br/><b>RESULTS AND DISCUSSION</b><br/>A preliminary study showed that GO-PEG was not toxic for cells at any concentration tested compared to cells only. A significant cell viability reduction was detected at 30 μM GO-PEG-Pt for all cell lines compared to Pt-free, reaching 70% cell mortality in MG63 (p value ≤ 0.0001) and SAOS-2 (p value ≤ 0.001). Morphological analyses showed a round-shape cell morphology and cell number reduction in the presence of GO-PEG-Pt respect to Pt-free in a dose dependent trend. Cellular uptake of GO-PEG-Pt was significantly higher after 24h for SAOS (p value ≤ 0.05) and MG63 (p value ≤ 0.0001) cell lines than Pt-free. The cell migration was lower in Go-PEG-Pt than Pt-free in MG63 and U2 with overall more than 60% migration inhibition over time at 30 µM concentration.<br/> <br/><b>CONCLUSION</b><br/>The results confirmed that GO-PEG-Pt platforms work as promising anticancer delivery systems. In fact, all the three osteosarcoma cell lines showed higher susceptibility to GO-PEG-Pt in terms of lower metabolic activity and lower migration rates due to the higher GO-PEG-Pt uptake compared to Pt-free.<br/> <br/><b>REFERENCES</b><br/>1. Tang, Q.L. <i>et al.</i>, Cancer Lett., 113:121, 2011<br/>2. Xiao, X. <i>et al.,</i> J Exp Clin Cancer Res, 37:201, 2018<br/>3. World Health Organization – Cancer, 2021<br/>4. Hulvat MC., Cancer Incidence and Trends. Surg. Clin. North Am. W.B. Saunders, 2020<br/>5. Schirrmacher V., Int J Oncol., 54:407–19, 2019<br/>6. Johnstone TC, <i>et al.</i> Chem. Rev. American Chemical Society, 3436–86, 2016<br/>7. Gmeiner WH <i>et al.,</i> Nanotech. Rev., 3:111–22, 2014<br/>8. Bersini S, <i>et al.</i> J Biomaterials 35:2454–61, 2014<br/>9. Lei S <i>et al.,</i> Cancer Commun. 1–12, 2021<br/>10. Rajaratnam V. <i>et al.,</i> Cancers, 2020<br/>11. Ottaviani G. JN., Cancer Treat Res., 152:33, 2019<br/> <br/><b>ACKNOWLEDGMENTS</b><br/>The authors would like to thank the Nano4Tarmed project (H2020-WIDESPREAD-2020-5, grant no: 952063) for providing financial support to this project.