Hyaluronic acid optimizes therapeutic effects of Hydrogen peroxide-induced oxidative stress on breast cancer
Abstract Background and Purpose: Distinguishing the multiple effects of reactive oxygen species (ROS) on cancer cells is important to understand their role in tumour biology. Conversely, elevated levels of ROS-induced oxidative stress can induce cancer cell death. However, some anti-oxidative or ROS-mediated oxidative therapies have also yielded beneficial effects.Experimental approach: To better define the effects of oxidative stress, in vitro experiments were conducted on 4T1 and splenic mononuclear cells (MNCs) under hypoxic and normoxic conditions. Furthermore, H2O2 [10-1000μM], was used as a ROS source alone or in combination with hyaluronic acid (HA), which is frequently used as drug delivery vehicle.Key Results: Our results indicate that treatment of cancer cells with H2O2+HA was significantly more effective than H2O2 alone. In addition, treatment with H2O2+HA led to increased apoptosis, decreased proliferation, and multi-phase cell cycle arrest in 4T1 cells in a dose-dependent manner under normoxic or hypoxic conditions. Also, migratory tendency and the mRNA levels of VEGF, and MMP-2,9 were significantly decreased. Of note, HA treatment combined with 100-1000μM H2O2+ caused more damage to MNCs as compared to treatment with lower concentrations [10-50μM]. Based on these results we propose to administer high dose H2O2+HA [100-1000μM] for intra-tumoral injection and low doses for systemic administration.Conclusions & Implications: Intra-tumoral route could have toxic and inhibitory effects not only on the tumour but also on residential myeloid cells defending it, whereas systemic treatment could stimulate peripheral immune responses against the tumour. More in vivo research is required to confirm this hypothesis.