generating-murine-orthotopic-metastatic-breast-cancer-model

Generating a Murine Orthotopic Metastatic Breast Cancer Model and Performing Murine Radical Mastectomy

In vivo mouse models to assess breast cancer progression are essential for cancer research, including preclinical drug developments. However, the majority ...

Holy Cross Hospital Michael and Dianne Bienes Comprehensive Cancer Center

Massachusetts General Hospital

University of Miami

Nova Southeastern University School of Medicine

The tumor microenvironment is a determining factor for cancer biology and progression. Sphingosine-1-phosphate (S1P), produced by sphingosine kinases (SphKs), is a bioactive lipid mediator that regulates processes important for cancer progression. Despite its critical roles, the levels of S1P in interstitial fluid (IF), an important component of the tumor microenvironment, have never previously been measured due to a lack of efficient methods for collecting and quantifying IF. The purpose of this study is to clarify the levels of S1P in the IF from murine mammary glands and its tumors utilizing our novel methods. We developed an improved centrifugation method to collect IF. Sphingolipids in IF, blood, and tissue samples were measured by mass spectrometry. In mice with a deletion of SphK1, but not SphK2, levels of S1P in IF from the mammary glands were greatly attenuated. Levels of S1P in IF from mammary tumors were reduced when tumor growth was suppressed by oral administration of FTY720/fingolimod. Importantly, sphingosine, dihydro-sphingosine, and S1P levels, but not dihydro-S1P, were significantly higher in human breast tumor tissue IF than in the normal breast tissue IF. To our knowledge, this is the first reported S1P IF measurement in murine normal mammary glands and mammary tumors, as well as in human patients with breast cancer. S1P tumor IF measurement illuminates new aspects of the role of S1P in the tumor microenvironment.

Interstitial Fluid Sphingosine-1-Phosphate in Murine Mammary Gland and Cancer and Human Breast Tissue and Cancer Determined by Novel Methods.

Doxorubicin is one of the most commonly used chemotherapeutic drugs for breast cancer; however, its use is limited by drug resistance and side effects. We hypothesized that adding FTY720, a sphingosine-1-phosphate (S1P) receptor functional antagonist, to doxorubicin would potentiate its effects by suppression of drug-induced inflammation.

Doxorubicin effect is enhanced by sphingosine-1-phosphate signaling antagonist in breast cancer.

Despite massive expenditures in preclinical studies, many breast cancer agents show efficacy in murine models but fail in human trials. In humans, metastatic disease determines survival, but preclinical murine models only evaluate drug efficacy against the primary tumor. We hypothesized that evaluating efficacy against metastatic breast cancer would more efficiently predict efficacy in a murine model than evaluating the primary tumor alone. This study (1) critically evaluated a murine tumor removal model with metastatic tumor burden quantification for breast cancer preclinical trials and (2) validated the model with an agent that previously passed preclinical trials but failed human trials.

Omar M. Rashid

Holy Cross Hospital Michael and Dianne Bienes Comprehensive Cancer Center

Generating a Murine Orthotopic Metastatic Breast Cancer Model and Performing Murine Radical Mastectomy