[Intermolecular Interactions between Cytisine and Bovine Serum Albumin A Synchronous Fluorescence Spectroscopic Analysis and Molecular Docking Research].

Cytisine (Cy) is one of the alkaloids that exist naturally in the plant genera Laburnum of the family Fabaceae. With strong bioactivities, Cy is commercialized for smoking cessation for years. In this work, the study of intermolecular interactions between Cy and bovine serum albumin (BSA) was performed by applying fluorescence spectroscopic methods under simulated physiological conditions. The mechanism of fluorescence quenching of BSA by Cy was also studied. Parameters such as bathing temperature, time and solution pH were investigated to optimize the fluorescence quenching. The binding type, binding ratio and binding constant between BSA and Cy were calculated by using the Stem-Volmer equation. Experimental results indicated that Cy can quench the fluorescent emission of BSA statically by forming a 1 : 1 type non-covalent complex and the binding constant is 5.6 x 10(3) L x mol(-1). Synchronous fluorescence spectral research shows Cy may affect the fluorescence emission of Trp residues of BSA. Furthermore, molecular docking is utilized to model the complex and probe the plausible quenching mechanism. It can be noted that the hydrogen bindings and hydrophobic interactions between Cy and BSA change the micro-environment of Trp213, which leads to the fluorescence quenching of BSA.

Efficacy and prognosis of neoadjuvant chemotherapy is correlated with breast cancer molecular classification.

Breast cancer is one of the most common cancers affecting women globally. Recent studies have begun to investigate the possibility of customized treatment options for individuals based on the specific cancer type. Here, we sought to analyze the relationship between the molecular classification of breast cancer and the efficacy and prognosis of neoadjuvant chemotherapy (NCT). The study included 100 breast cancer patients treated with an NCT regimen of epirubicin and docetaxel (ET) who were divided into groups based on cancer subtype (luminal, HER2 over-expression, and basal-like subtype). The nuclear classification, number of NCT cycles, pathological remission rate, and clinical curative effect, as well as the disease-free survival time (DFS) and the overall survival (OS), were compared across groups. The nuclear grade of participants in the basal-like group was significantly higher than those in the other groups but this group had fewer preoperative NCT cycles and lower pathological remission and clinical efficacy (Z=53.245, 50.077, 62.467, χ2=16.082, p<0.05). The OS and DFS of participants in the luminal subtype group were significantly higher than those in other groups while those in the basal-like subtype group were the lowest. The OS and DFS of participants who achieved pathological complete remission (pCR) through NCT treatment were significantly higher than those of the patients who had not achieved pCR through NCT treatment (χ2=9.558, 10.139, p<0.05). Therefore, we conclude that when NCT (ET regimen) is used in the treatment of breast cancer, the curative effects and prognosis appear to be correlated with the molecular classification of the tumor. Based on these results, clinicians should consider the molecular classification of the individual tumor to design the most effective treatment option.