Sample Scientific Paper

Investigating how macrophages and adipocytes influence breast cancer metastasis using the chick embryo model

Yuko Imaizumi, Kayuri Kadoya, Stephanie Tsang Mui Chung, Ashleigh Renaud and Linda Connelly

Department of Pharmaceutical Science University of Hawaii at Hilo, 200 W. Kawili Street, Hilo, HI 96720 USA.

Personal Reflection
I enjoyed my experiments with Professor Connelly and other lab workers, even though it was not easy starting for me. Animal experiments were my first trial, and I didn’t know how to do PCR and ELISA until I joined in Dr. Connelly’s lab. I had only a slight understanding of my research topic, the progress of experiments, and data analyzing. Dr Connelly and her postdoc, Dr Tsang Mui Chung, answered all my questions and helped me make great progress in my research. I finally understood my research topic well and made my poster presentation at the JABSOM conference with confidence. I really appreciate all of the help from Dr. Connelly, the HCC lab coordinator Ms. Adams and the INBRE program for giving me a great experience.

Introduction
Obese women with breast cancer are more likely to have metastases. In adipose tissue, macrophage recruitment increases. Macrophages have been shown to promote breast cancer metastasis. We believe it is the interaction between the adipocytes and the macrophages that causes the increase in metastasis seen in obese patients. Thus, we hypothesize that the interaction between adipocytes and macrophages within obese breast tissue promotes breast cancer growth and metastasis. In the current study, we aimed to prove that adding either macrophages or adipocytes to the tumor cells would increase tumor growth and metastasis.

Figure 1. Diagram showing our hypothesis of how obesity promotes breast cancer development and metastasis through the interaction between adipocytes and macrophages.

Method and Materials
To test our hypothesis, we used the chick embryo model. Mouse mammary tumor cells (4T1) and murine macrophages (J774A.1) or murine adipocytes (3T3-L1) were inoculated on the chick chorioallantoic membrane (CAM) on the 10th embryonic day. The primary tumor and the chick tissues from liver, lung, and CAM contralateral to the inoculation site were harvested on the 17 the embryonic day. First, we weighed primary tumors to look at effect on tumor growth. Then we fixed the tumor tissues in formalin, embedded, then looked in tissue sections for the different cell types. Finally, in order to detect metastasis, we extracted DNA from chick tissue and performed qPCR for mouse Alu sequences. A total of 4 experiments were performed: 3 for 4T1 mouse mammary tumor cells and J774A.1 mouse macrophages, 1 for 4T1 and 3T3-L1 mouse…