临床与实验肿瘤学杂志

Olive Leaf Extract Reduces Myeloid-Derived Suppressor Cells, and Modulates the Function of Residual Cells in Experimental Model of Melanoma

Mahboubeh Ashourpour, Afshin Namdar, Nasim Kheshtchin, Morteza Hafezi, Najmeh Khosravianfar, Maryam Ajami, Bahram Delfan,Yaser Azizi, Samaneh Arab8, Reza Mirzaei, Abbas Mirshafiey, Jamshid Hadjati, Alireza Razavi

Background: Immunosuppression in melanoma is mediated by increased accumulation of Myeloid Derived Suppressor Cells (MDSCs). Olive Leaf Extract (OLE) has been developed as a natural anti-inflammatory, anti-oxidant, anti-proliferative and antiapoptotic agent on cancer immunotherapy.

Objective: To investigate whether OLE could inhibit MDSCs, enhance anti-tumor activities and consequently increase the survival rate of the murine melanoma model.

Methods: The C57BL/6 mice were inoculated subcutaneously with B16/F10 melanoma tumor cell lines. Induced mice were orally treated with 500 mgkg-1 of olive extract per kg of body weight for 8 consecutive days. The frequency and function of MDSCs and induction of inflammatory mediators as well as tumor growth and survival rate were assessed in treated and untreated mice.

Results: The results of current study revealed that the optimal dose of OLE (500 mgkg-1) reduced the tumor growth (40%), and prolonged mice survival (25%) by significant decreasing (P<0.05) the number (over 50%), and suppressive function of MDSCs (over 60%) (P<0.05). OLE was also significantly (P<0.05) down regulated the induction of inflammatory agents in melanoma-bearing mice (over 50%) at the applied dose (500 mgkg-1).

Conclusion: Therefore, these results altogether provided some evidence that regulation of immunosuppression were the possible therapeutic effects of OLE in tumor cells.