Exemestane-RAD001-Metformin

Study Drug Administration: If you are found to be eligible to take part in this study, you will take an exemestane and everolimus tablet by mouth every day. You will also take tablets of metformin by mouth 2 times a day. The drugs should be taken at about the same time each day. The study drugs will be given in 28-day cycles. Study Visits: On Day 1: * You will have a physical exam, including a measurement of your weight and vital signs. * You will be asked about any side effects you may be having. * You will be asked about any drugs you may have taken or may be taking. * Your performance status will be recorded. * Blood (about 1-2 teaspoons) will be drawn for routine tests. * Blood (about 1 teaspoon) will be drawn for blood sugar tests. If you have a history of diabetes, you will need to fast for 8 hours before these blood sugar tests. At Weeks 4 and 12: * You will have a physical exam, including a measurement of your vital signs. * You will be asked about any side effects you may be having. * You will be asked about any drugs you may have taken or may be taking. * Blood (about 1-2 teaspoons) will be drawn for routine tests. * Blood (about 1 teaspoon) will be drawn for blood sugar tests. If you have a history of diabetes, you will need to fast for 8 hours before these blood sugar tests. At Weeks 8, 16 and then every 2 months after that, and after your last dose of study drugs: * You will have a physical exam, including a measurement of your vital signs. * You will be asked about any side effects you may be having. * You will be asked about any drugs you may have taken or may be taking. * Blood (about 1-2 teaspoons) will be drawn for routine tests. * Blood (about 4 teaspoons) will be drawn for biomarker testing (at weeks 8, 16 and 24 only). * Blood (about 1 teaspoon) will be drawn for blood sugar tests. If you have a history of diabetes, you will need to fast for 8 hours before these blood sugar tests. * You will have imaging scans to check the status of the disease. Length of Study: You may continue taking the study drugs for as long as the doctor thinks it is in your best interest. You will no longer be able to take the study drugs if the disease gets worse, if intolerable side effects occur, or if you are unable to follow study directions. This is an investigational study. Exemestane is FDA approved and commercially available for the treatment of metastatic breast cancer. Metformin is FDA approved and commercially available for the treatment of diabetes. Everolimus is FDA approved and commercially available to treat metastatic breast cancer, advanced kidney cancer in some patients and a certain type of brain tumor. The use of this drug combination is investigational. Up to 40 patients will take part in this study. All will be enrolled at MD Anderson.