Metabolic relevance for N-hydroxy L-arginine reduction in estrogen-negative breast cancer cells.

We had shown Nw-hydroxy-L-arginine (NOHA) as a promising blood-based biomarker for estrogen-receptor-negative (ER-) breast cancer (BC) that differentiates ER- BC based on grade and molecular phenotype. In this in vitro study, we assessed the metabolic relevance for ER- BC-specific NOHA modulation and correlated them with NOHA regulatory responses. This study aids future NOHA clinical utility in ER- BC diagnosis and therapy management and would prove useful for potential drug discovery and development process.

Competitive ELISA method for novel estrogen-negative breast cancer biomarker quantitation.

Estrogen-negative (ER-) breast cancer, is recognized as an aggressive subtype, more difficult to treat, with poor survival and prognosis. They are hormonally unresponsive, with no readily effective and specific target therapy. We have previously identified Nw-hydroxy L-Arginine (NOHA) as a blood-based biomarker to distinguish between ER- and ER+ breast cancer tumors based upon disease burden, progression and molecular phenotype (U.S. Utility Patent 10,073,099). In this study we have demonstrated a competitive ELISA based assay for NOHA measurement using a proprietary monoclonal antibody (mAb) specific for NOHA (U.S. provisional patent 62/754,053). The ELISA assay was evaluated on sensitivity, selectivity, precision, dilution linearity and percent recovery parameters. The assay showed sensitivity at ≥60 pg/ml NOHA antigen with 1 ng/ml NOHA mAb, and maintained NOHA antigen specificity even in the presence of other closely related cationic amino acids (i.e. L-Arginine, D-Arginine, l-Lysine, d-Lysine, L-Ornithine, and L-Citrulline). The reliability of the ELISA protocol was confirmed with the low percent-covariance, for all tested parameters of sensitivity (≤8.2%), selectivity (≤8.6%), precision (≤12.6%), dilution linearity (≤11.2%) and recovery (≤6.7%). Additionally, we can demonstrate NOHA quantification by this ELISA assay to complement the sensitivity achievable with LC-MS (in both assay buffer and with patient plasma samples), thus suggesting it's utility as a simple yet sensitive methodology that might help in ER- breast cancer prognosis, and disease progression monitoring without the need for expensive analytical equipment (such as LC-MS), large lab space, or specialized technical training.

Weight Loss Intervention in Survivors of ER/PR-negative Breast Cancer.

Numerous studies have found that increased body size (weight or body mass index) is a risk factor for breast cancer development, recurrence, and death. The detrimental relationship between body size and breast cancer recurrence may be more pronounced among women with estrogen receptor (ER)/progesterone receptor (PR)-negative breast cancer. Considering the limited availability of treatments, and the association between body size and recurrence, alternative treatments are needed for ER/PR-negative breast cancer survivors, particularly overweight survivors. The objective of this pilot study was to examine the feasibility of a 12-week, multi-component meal-replacement weight loss intervention among overweight or obese ER/PR-negative breast cancer survivors; and to obtain preliminary data on changes in anthropometrics, biomarkers, and health-related quality of life (QOL). The 12-week intervention included a portion-controlled diet (including meal replacements) and a multi-component intervention (including behavioral techniques, diet modification, physical activity, and social support). The goal of the intervention was to help participants lose 5% or more of their initial weight by reducing their caloric intake and increasing their physical activity (to at least 15 minutes each day). Paired t-tests assessed changes in continuous measures. Body weight was measured weekly and mixed-model regression analysis assessed change in weight over time. Nineteen ER/PR-negative breast cancer survivors with a mean age of 59 years participated in the study. All but two of the participants completed the 12-week intervention. Women lost an average of 6.3 ± 4.9 kg (P < 0.001), equivalent to 7.5% of their baseline weight. There were significant reductions in waist circumference (P = 0.001), percent fat mass (P < 0.001), total cholesterol (P = 0.026), and triglycerides (P = 0.002); and improvements in health-related QOL (P = 0.017). Findings suggested that a meal-replacement weight loss approach among ER/PR-negative breast cancer survivors was feasible and was well received.