Background/Objectives: The renin–angiotensin system (RAS) is well-established as a moderator of cardiovascular equilibrium and blood pressure. Nevertheless, growing evidence indicates that angiotensin II (Ang II), the principal RAS effector peptide, together with additional constituents, is involved in various malignancies. Since the immune system is an important aspect in tumor development, this study sought to investigate the role of Ang II in the crosstalk between tumor-associated macrophages (TAMs) and breast cancer cells in the tumor microenvironment (TME). Methods: We treated THP-1-like macrophages with 100 nM Ang II for 24 h. The culture media thus obtained was used as conditioned media and applied at 50% on MCF-7 and MDA-MB-231 breast cancer cell lines. The effects of the conditioned media on cancer cell lines were then investigated by various methods such as a cell proliferation assay, migration assay, polarization assay, and by the detection of apoptosis and reactive oxygen species (ROS) generation. Results: We demonstrated that in vitro Ang II promotes macrophage polarization toward proinflammatory M1-like macrophages and anti-inflammatory M2-like macrophages. Interestingly, Ang II, through macrophages, showed varied effects on different breast cancer cell lines, promoting tumor growth and progression in MCF-7 while inhibiting tumor growth and progression in MDA-MB-23. Conclusions: This study has provided clear evidence that Ang II in the TME modulates TAM polarization and secretions, leading to different effects based on the type of breast cancer.

Streptomyces strains are renowned for their ability to produce a wide array of secondary metabolites, which play crucial roles in ecological interactions and have significant pharmaceutical applications. The optimization of culture conditions is a key factor in maximizing the production of these bioactive compounds. This study investigated the growth patterns and bioactivity of a newly isolated Streptomyces gobitricini cultured on different media: R5, R5E, R2YE, and YEME. Data showed that R5 and R2YE media supported higher biomass accumulation, achieving peak dry weights of 225 mg/L and 175 mg/L, respectively, after 96 h-incubation, compared to R5E (52 mg/L) and YEME (48 mg/L). Growth phases, especially the exponential phases, were longer and more pronounced in nutrient-rich media like R5 and R2YE. Furthermore, the inherent antioxidant activities, enzyme inhibitory properties against α-amylase, α-glucosidase, lipase, and trypsin, as well as secreted phospholipase A2, cyclooxygenases and lipooxygenase, showed significant variations influenced by the growth media, with R5 exhibiting the highest overall bioactivity. Specifically, R2YE extracts demonstrated potent inhibitory effects on α-glucosidase and phospholipases, while YEME showed promising lipase inhibition. These findings emphasized the critical role of media composition in promoting secondary metabolite production in S. gobitricini, ultimately enhancing its potential medicinal applications for several human diseases such as obesity and inflammation. Consequently, optimizing bacterial culture conditions could significantly improve yield and efficiency of bioactive compounds.