Aromatase inhibitors anastrozole and letrozole (non-steroidal, reversible), and exemestane (steroidal, irreversible) are approved standard therapies (Food and Drug Administration) for hormone receptor-positive breast cancer. Their use is limited by Aromatase Inhibitor-induced Musculoskeletal Signs and Symptoms (AIMSS). Articles on AIMSS mechanisms and biomarkers published between January 1, 1990, and October 31, 2024, in PubMed, EMBASE, and Cochrane Library were identified. Included study designs were randomized and non-randomized trials, observational cohorts, cross-sectional studies, and preclinical animal models. Risk of bias was assessed using the Critical Appraisal Skills Programme tool for observational studies and Risk of Bias 2 for randomized trials. Fifty studies were included (43 human and seven animal). Estrogen deprivation was the central mechanism, affecting immune function, bone remodeling, and nociceptive sensitivity. Genetic variants in Estrogen Receptor 1, CYP19A1, and T-cell Leukemia/Lymphoma 1A were frequently associated with AIMSS. Vitamin D deficiency, polymorphisms in RANKL and Osteoprotegerin contributed to bone-related symptoms. Imaging studies identified tenosynovial thickening, tendon sheath fluid, and subclinical inflammation. Systemic inflammatory markers C-Reactive Protein and Interleukin 6 were elevated in human and animal studies. Transient Receptor Potential Ankyrin 1 and Transient Receptor Potential Vanilloid 4 ion channels were implicated in peripheral sensitization. Insulin-like Growth Factor 1 during AI therapy was independently associated with symptoms. AIMSS involves intersecting hormonal, genetic, inflammatory, and neural pathways. Identification of mechanistic biomarkers may support AIMSS risk stratification and targeted interventions. Further research should validate multi-omic models and explore new strategies to reduce AIMSS and improve treatment compliance. PROSPERO Registration: CRD42025642540.

Background: Colorectal cancer (CRC) is the second leading cause of cancer-related mortality worldwide. The search for effective, new antineoplastic drugs with fewer side effects for the treatment of CRC continues, with marine-derived compounds emerging as promising candidates. Objectives: This study investigates the anticancer potential of Frondanol, a nutraceutical derived from the Atlantic Sea cucumber Cucumaria frondosa, known for its potent anti-inflammatory properties. Methods: Two human CRC cell lines, Caco-2 and HT-29, were used to test the effects of Frondanol using various in vitro approaches. Results: Frondanol significantly inhibited cell viability in a dose- and time-dependent manner. At a 1:10,000 dilution, viability decreased to around 30% in Caco-2 and 20% in HT-29 after 24 h, dropping to nearly 5% at 48 h. Furthermore, a clonogenic assay showed around 50% reduction in colony formation in both cell lines. Flow cytometry-based Annexin V staining revealed that Frondanol increased early apoptosis to ~5.2% in Caco-2 and ~9.4% in HT-29 cells, while cell cycle analysis showed accumulation of the sub G0 (apoptotic) phase increasing from 1.5% to 14.7% (Caco-2) and from 1.9% to 23.8% (HT-29). At the molecular level, Frondanol treatment significantly decreased anti-apoptotic protein B-cell lymphoma (Bcl)-2 expression while increasing the expression of the proapoptotic protein Bcl-2-associated X-protein. Additionally, Frondanol markedly induced cytochrome c release from the mitochondria and activated caspase-9, caspase-7, and caspase-3 after treatment, alongside cleavage of the caspase-3 substrate poly (ADP-ribose) polymerase. Frondanol inhibited 5-lipoxygenase activity, further contributing to its anticancer effects. Conclusions: In conclusion, Frondanol inhibits CRC cell proliferation and induces apoptosis through the mitochondrial pathway in vitro, suggesting that it is a potential nutraceutical for the prevention of human colorectal cancer or a valuable source of anticancer compounds.