Purpose: Achieving a pathological complete response (pCR) after neoadjuvant therapy in HER2-positive breast cancer patients is the most significant prognostic indicator, suggesting a low risk of recurrence and a survival advantage. This study aims to investigate clinicopathological parameters that can predict the response to neoadjuvant treatment in HER2 + breast cancers and to explore the roles of tumour-infiltrating lymphocytes (TILs), CD8 + T lymphocytes and PD-L1 expression. Methods: This single-centre retrospective study was conducted with 85 HER2-positive breast cancer patients who underwent surgery after receiving neoadjuvant therapy between January 2017 and January 2020. Paraffin blocks from these patients were selected for immunohistochemical studies. Results: A complete pathological response to neoadjuvant treatment was determined in 39 (45.9%) patients. High Ki-67 index (> 30%), moderate to high TIL infiltration, PD-L1 positivity and high CD8 cell count (≥ 25) were significantly associated with pCR in univariate analyses (p: 0.023, 0.025, 0.017 and 0.003, respectively). Multivariate regression analysis identified high Ki-67 index (> 30%) and CD8 cell infiltration as independent predictors for pCR in HER2-positive breast cancer. Conclusions: High Ki-67 index, and high CD8 cell count are strong predictors for pCR in HER2-positive breast cancer. Tumours with high Ki-67 index, high TILs and CD8 infiltration may represent a subgroup where standard therapies are adequate. Conversely, those with low TILs and CD8 infiltration may identify a subgroup where use of novel strategies, including those that increase CD8 infiltration could be applied.

Objective: Alzheimer’s disease is a neurodegenerative sickness and increasing with age throughout the world. A substantial body of evidence suggests the role of exosomal noncoding ribonucleic acids in the development of Alzheimer’s disease, but the regulatory mechanisms mediated by these noncoding ribonucleic acids remain extensively unknown. Using plasma samples from Alzheimer’s disease patients, this study explored the exosomal circular ribonucleic acid–microribonucleic acid profiles. Materials and Methods: The ArrayExpress platform was used to convey data from 3 samples from each group (healthy, mild cognitive impairment, and Alzheimer’s disease). Using plasma exosomes, differentially expressed microribonucleic acids and differentially expressed circular ribonucleic acids were compared between the Alzheimer’s disease and mild cognitive impairment groups. Afterward, to define pathways, gene ontologies, and networks, differentially expressed microribonucleic acids and differentially expressed circular ribonucleic acids common to both mild cognitive impairment and Alzheimer’s disease groups were analyzed. Eventually, the selection of hub genes and protein–protein interaction network was analyzed. Results: A total of common 19 (7 upregulated and 12 downregulated) differentially expressed microribonucleic acids and 24 differentially expressed circular ribonucleic acids were recognized. A total of 4559 target genes were predicted for upregulated differentially expressed microribonucleic acids, while 6504 target genes were identified for downregulated differentially expressed microribonucleic acids, and most of the target genes involved in the phosphoinositide 3-kinases-Akt pathway and that were mostly regulated by hsa-mir-374a-3p, mir-196a-5p, let-205-5p, mir-185-3p, mir-374a-5p, mir-615-3p, let-7c-5p, mir-185-5p. Additionally, 9 hub genes (HSP90AA, ACTB, MAPK1, GSK3B, CCNE2, CDK6, AKT1, IGF1R, CCND1) were revealed as the genes considerably related to Alzheimer’s disease by a protein–protein interaction network using the cytohubba in Cytoscape software. Conclusion: Our findings provide a new perspective on how microribonucleic acids could connect with circular ribonucleic acids in the pathogenesis of Alzheimer’s disease. Cite this article as: Besli N, Sarikamis B, Kalkan Cakmak R, Kilic U. Exosomal circular ribonucleic acid–microribonucleic acid expression profile from plasma in Alzheimer’s disease patients by bioinformatics and integrative analysis. Eurasian J Med., 2023;55(3):218-227.

Understanding the mechanism behind Alzheimer’s disease is imperative due to the critical role of the autophagy pathway in protein homeostasis and neuronal survival. Autophagy pathway irregularities in neurons may increase exosome-mediated toxic protein transport, which can spread neurodegenerative diseases. Compelling evidence hints that acacetin (ACA) is a naturally occurring biocomponent exhibiting neuroprotective pharmacological properties. However, further molecular investigations are pressing to uncover the therapeutic potential of ACA. The present investigation endeavors to scrutinize the impact of ACA on the autophagy pathway and exosome release in an amyloid beta (Aβ) peptide-induced toxicity model. Herein, first, molecular modeling was performed between ACA and autophagy-related proteins. Afterward, the Aβ peptide-induced toxicity model cells were treated with ACA, and total and exosomal protein isolation was carried out and analyzed. Considering the findings, our molecular dynamics simulation of the ACA-protein complexes, spanning 100 ns, conclusively demonstrated stable protein–ligand interactions. Additionally, ACA was determined to regulate LC3II, Beclin-1, p62, and Lamp2a protein levels and reduce amyloid-β and Alix protein levels. In conclusion, our study highlights the significant in vitro neuroprotective effect of ACA against Aβ toxicity through autophagy. Moving forward, future studies may seek to elucidate the specific neuroprotective, therapeutic effects and mechanisms of ACA via autophagy in in vivo models. Addressing the identified limitations and capitalizing on the outlined future prospects are essential steps towards harnessing the therapeutic potential of ACA in combating neurodegenerative diseases, offering renewed hope for patients and caregivers alike.