Neutrophil activation causes tumor regression in Walker 256 tumor-bearing rats

Author(s)

Tatagiba Kuwabara, Wilson Mitsuo ^[1] ; Andrade-Silva, Jessica ^[1] ; Bertaglia Pereira, Joice Naiara ^[2] ; Scialfa, Julieta Helena ^[1] ; Cipolla-Neto, Jose ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, Sao Paulo - Brazil

^[2] Cruzeiro do Sul Univ, Interdisciplinar Hlth Sci Postgrad Program, Sao Paulo - Brazil

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 9, NOV 11 2019.
• Web of Science Citations: 0

Abstract

The role of neutrophils in cancer is still very contradictory. Several studies have demonstrated the cytotoxic capacity of neutrophils against different types of tumors, by releasing inflammatory cytokines, ROS and activating other immune cells. On the other hand, recent papers have claimed the protumorigenic action of neutrophils, mainly by changing their phenotype and producing cytokines that promote tumor growth. In this context, this study aimed to evaluate neutrophil action and function during tumor development. To do so, we used male Wistar rats inoculated with Walker 256 breast carcinoma. Tumor, circulating neutrophils and bone marrow were studied in the following time points after tumor inoculation: 12 h, 24 h, 48 h, 3 d, 5 d, 7 d, 10 d, and 14 d, in order to analyze neutrophil migration kinetics, circulating neutrophil phenotype and bone marrow response to the tumor growth. Herein, our results demonstrated that W256T was unable to trigger an intratumoral inflammatory response after 5 days of tumor development and consequently, from that point on, prevented neutrophil migration to its microenvironment. Also, the tumor changed circulating neutrophil phenotype by up-regulating inflammation-related genes. Even though circulating neutrophils were entirely able to respond to an inflammatory stimulus, they did not recognize and attack the tumor, allowing the tumor to grow without any immune interference. To promote the entry of neutrophils into the tumor microenvironment, LPS was injected intratumorally. Neutrophil migration and activation due to LPS injection resulted in complete tumor regression in all subjects. In conclusion, activating neutrophils, within the tumor, turned the carcinoma into a recognizable immune target and eliminated it. (AU)

• FAPESP's process: 17/15036-1 - Effect of Melatonin on the Phenotype and Function of Neutrophils in Wistar Rats with Walker-256 Tumor.
• Grantee: Wilson Mitsuo Tatagiba Kuwabara
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/50457-0 - Melatonin and the control of energy metabolism: basic, clinical and epidemiological research
• Grantee: José Cipolla Neto
• Support Opportunities: Research Projects - Thematic Grants