Anti-Tumor Effects of Liposome-Encapsulated Titanium Dioxide in Nude Mice

Abstract

Anatase particles of titanium dioxide (TiO₂) absorb ultraviolet (UV) light which is shorter than 415 nm. Photoexcited TiO₂, a strong oxidizer, is expected to inhibit malignant cell growth. Liposomes accelerate endophagocytosis to the cytoplasm of encapsulated materials. In this study, we examined anti-tumor effects of TiO₂ and liposome-encapsulated TiO₂ (LT) with UVA irradiation by an air pouch cancer model using NBT-II bladder cancer cells, which simulates bladder cancer. Injection of TiO₂ or LT into the air pouch was followed by UVA irradiation via the opened pouch. Tumors of TiO₂ + UVA and LT + UVA groups showed more pronounced necrotic areas, apoptotic indices, nitrotyrosine formation, tumor growth inhibition and increased survival compared with control groups. Especially the LT + UVA group showed more remarkable anti-tumoral effects than the TiO₂ + UVA group, which was associated with higher TiO₂ incorporation. These findings suggest that LT might be more effective than noncoated TiO₂ in the treatment of bladder cancer.

Cancer Usurps Skeletal Muscle as an Energy Repository

“…Cells were transfected with 50 nmol/L siRNA using Lipofectamine 2000 (Invitrogen), according to the manufacturer's instructions. For administration of GLS glutaminase miTarget miRNA (GeneCopoeia), 100 pmol of miRNA was encapsulated in 2 mL of cationic liposome (EL-C-01, DPPC: 26 mmol/L, Nippon Oil&Fats), and 200 mL of the solution was administered intraperitoneally twice a week (28,29).…”

Nanosonotechnology: the next challenge in cancer sonodynamic therapy

“…Xu et al [42] reported that the combination of the electroporation and the conjugation of TiO 2 with the monoclonal antibody could improve the photo-killing selectivity and effi ciency of photo-excited TiO 2 on cancer cells in PDT. Chihara et al [43] found that liposome-encapsulated TiO 2 might be more effective than non-coated TiO 2 in the treatment of bladder cancer, and these modifi ed TiO 2 might also be a more effective material for SDT because ultrasound irradiation is an alternative energy source for TiO 2 [43] . The recent clinical introduction of HIFU, the non-invasive thermal ablation method that can be targeted to tissues without damaging surrounding normal structures, could be applied as an alternative method to locally irradiating tumors in combination with TiO 2 [41] .…”

Sonodynamic therapy using water-dispersed TiO2-polyethylene glycol compound on glioma cells: Comparison of cytotoxic mechanism with photodynamic therapy

“…The photocatalytic effect of TiO 2 has been applied to cancer treatment [20][21][22][23][24][25], and US irradiation is an alternative energy source for TiO 2 [26][27][28]. Furthermore, toxicological examinations have shown that the TiO 2 nanoparticle is basically nontoxic for experimental cells or animals [29][30][31].…”