Metformin Hydrochloride and Doxycycline in Treating Patients With Localized Breast or Uterine Cancer

This phase II trial studies how well metformin hydrochloride works together with doxycycline in treating patients with localized breast or uterine cancer. Metformin hydrochloride may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Doxycycline may stop the growth of bacteria by keeping them from making proteins and minimized the toxic side effects of anti-cancer therapy. It is not yet known whether giving metformin hydrochloride together with doxycycline may be a better way in treating patients with localized breast or uterine cancer.

PRIMARY OBJECTIVES: I. To determine if treatment with a combination of metformin and doxycycline can increase the percentage of cells that express Caveolin-1 in the cancer associated fibroblasts of patients with breast, or uterine, and cervical cancers. SECONDARY OBJECTIVES: I. To determine the effect of metformin and doxycycline treatment on the percentage of cells that express monocarboxylate transporter (MCT)4 in cancer associated fibroblasts and MCT1 and transporter of outer mitochondrial membrane (TOMM)20 in the cancer cells of breast and uterine cancer patients. II. To assess safety and tolerability of metformin and doxycycline treatment in subjects with breast and uterine cancer. III. To determine the relationship of the percentage of stromal cells expressing caveolin (CAV)1 or MCT4 and tumor cells that express MCT1 and TOMM20 at baseline and after treatment with metformin and doxycycline with the percentage of cells expressing estrogen receptor (ER) and progesterone receptor (PR) for breast and uterine samples and human epidermal growth factor (HER)2 in breast cancer samples. TERTIARY OBJECTIVES: I. To assess the effect of combined metformin and doxycycline therapy on the metabolic profile of cancer cells and stroma using mass spectroscopy imaging (MSI) on paired samples, comparing metabolite profiles in the pre-metformin and post-metformin tumor sample. II. To assess, when possible, the impact of a patient's nutritional status, estimated using 3 day dietary recall versus caloric needs as calculated by the Harris-Benedict equation on the baseline and net change in CAV1 III. To assess the effect of combined metformin and doxycycline therapy on oncomiR micro ribonucleic acid (RNA) (miR-21) after intervention. IV. To assess the effect of combined metformin and doxycycline therapy on adipokines and the insulin-like growth factor (IGF)-1/insulin signaling pathways through assessment of serum triglycerides, IGF-1, IGF-binding protein (BP)3, erythrocyte sedimentation rate (ESR), adiponectin, leptin, IGF-1 receptor (R), exosome evaluation, metabolomics profile, and microRNA expression profile.