1. Chemoprevention by cyclooxygenase-2 inhibition reduces immature myeloid suppressor cell expansion
- Author
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Laura R. Shafer, James E. Talmadge, Lori Zobel, Melissa Coles, Bela Toth, and Keith C. Hood
- Subjects
CD4-Positive T-Lymphocytes ,medicine.medical_specialty ,Myeloid ,T cell ,Immunology ,Nitric Oxide Synthase Type II ,Breast Neoplasms ,Spleen ,medicine.disease_cause ,Mice ,Adjuvants, Immunologic ,Internal medicine ,Intestinal Neoplasms ,Concanavalin A ,medicine ,Animals ,Anticarcinogenic Agents ,Immunology and Allergy ,RNA, Messenger ,Antigen-presenting cell ,Cell Proliferation ,Pharmacology ,Mice, Inbred BALB C ,Sulfonamides ,Arginase ,Cyclooxygenase 2 Inhibitors ,biology ,Cell growth ,Membrane Proteins ,1,2-Dimethylhydrazine ,Endocrinology ,medicine.anatomical_structure ,Celecoxib ,Carcinogens ,Cancer research ,biology.protein ,Pyrazoles ,Female ,Cyclooxygenase ,Carcinogenesis ,Neoplasm Transplantation ,medicine.drug - Abstract
Selective inhibitors of cyclooxygenase-2 (COX-2) enzyme activity have shown chemopreventive activity in carcinogen-induced and transgenic rodent tumor models and clinically for colon cancer. However, the mechanism(s) by which COX-2 inhibitors reduce carcinogenesis remains controversial. We report herein that administration of the selective COX-2 inhibitor, celecoxib, significantly reduces the number of Gr1(+)CD11b(+) immature myeloid suppressor cells (IMSCs) during chemoprevention of 1,2-dimethylhydrazine diHCl-(1,2-DMH-) induction of large intestinal tumors in Swiss mice. Celecoxib administration also increased splenic lymphatic number and tumor infiltration by lymphocytes. The 1,2-DMH induction of large intestinal tumors was associated with a four-fold increase in IMSCs, and a decrease in splenic T cell number and function. Concordant with the changes in the IMSC frequency, messenger ribonucleic acid (mRNA) levels of inducible nitric oxide synthase (NOS-2) and arginase (Arg) were increased in the spleen of the tumor-bearing mice and normalized by celecoxib administration. In addition to delaying tumor induction, reducing tumor number, and increasing lymphocyte infiltration of tumors, celecoxib therapy reversed CD4(+) T cell loss, decreased IMSC numbers and increased mRNA levels of NOS-2 and Arg in the spleen. In summary, our results suggest that celecoxib chemoprevention of autochthonous intestinal tumors can regulate IMSCs and CD4(+) T cell numbers.
- Published
- 2007