Abstract LB-456: The intraductal injection of 5-fluorouracil induces immune response to eradicate and prevent breast cancer

Abstract

Abstract Chemotherapy has been shown to act as an immune response modifier. Many groups, incuding our own, are using chemotherapy to induce immune responses such as by using low doses of cyclophosphamide. Our previous work has demonstrated that anti-cancer agents can eliminate new/existing tumors with minimal toxicity in rat and mouse models of breast cancer. Here we demonstrate that intraductal (i.duc), but not the intravenous (IV) route of injection, of chemotherapy to mammary glands alters the tumor environment to effectively induce immune effector cells. We used the mouse HER2/neu (neu/N) transgenic, spontaneous mammary tumor model. 5-fluorouracil (5FU) was administered intraductally to the mammary glands on the left side of parous mice whereas the mammary glands on right side received no treatment (NT). The mammary tumor incidence in the 5FU treated side was significantly lower compared to mice that received NT, and IV treated group. Interestingly the incidence of mammary tumors in the untreated side of 5FU-treated mice was also significantly lower compared to the NT and IV group. We hypothesized that the protection afforded to the contralateral chain of mammary glands by ipsilateral i.duc administration of 5FU, may be mediated through an immunological mechanism. Twenty week parous mice were administered 5FU either through i.duc injection, only to left side teats, IV injection, or NT. The mice received 5FU 2 times in a 4 week interval. A week after the second treatment, the mice were sacrificed and the regional lymphnodes (RLN) of the 3rd and 4th mammary glands and spleen were removed. We isolated lymphocyte from RLN and spleen to analyze by flowcytometry. The number of CD8 T cell showed no change among the groups in the RLN but was significantly lower in the i.duc group in the spleen. The number of CD62LLOW+ T cell in 5FU treated side of RLN was significantly higher compared to the IV and NT group. On the other hand the number of CD62LLOW+ was low in the spleen. To study the population of systemic memory T cell in the peripheral blood, blood was harvested into Trucount tubes and analyzed with memory T cells surface marker. Twenty week parous mice was administered 5FU i.duc injection only to the left side, IV injection, or NT every 4weeks for a total of 3 times. Cancer cells were injected into the left side of 4th mammary gland fat pad of the mice at 16 weeks after initial procedure. One hundred μl blood was collected 5 days before and 5 days after cancer cell injection. The mice treated by i.duc 5FU showed increased numbers of CD95+/CD62L low effector memory T (TEM) cells, whereas the mice treated with IV 5FU did not recruit TEM cells significantly. There was no significant change in CD95+/CD62L high central memory T cells before and after treatment and among the groups. In summary, i.duc administration of 5FU into mammary glands effectively induced immune effector cells and prevented mammary tumor growth in neu/N transgenic mice. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-456. doi:10.1158/1538-7445.AM2011-LB-456