Combination of Small Extracellular Vesicle-Derived Annexin A2 Protein and mRNA as a Potential Predictive Biomarker for Chemotherapy Responsiveness in Aggressive Triple-Negative Breast Cancer

Abstract

Small extracellular vesicles (sEVs), mainly exosomes, are nanovesicles that shed from the membrane as intraluminal vesicles of the multivesicular bodies, serve as vehicles that carry cargo influential in modulating the tumor microenvironment for the multi-step process of cancer metastasis. Annexin A2 (AnxA2), a calcium(Ca2+)-dependent phospholipid-binding protein, is among sEV cargoes. sEV-derived AnxA2 (sEV-AnxA2) protein is involved in the process of metastasis in triple-negative breast cancer (TNBC). The objective of the current study is to determine whether sEV-AnxA2 protein and/or mRNA could be a useful biomarkers to predict the responsiveness of chemotherapy in TNBC. Removal of Immunoglobulin G (IgG) from the serum as well as using the System Bioscience’s ExoQuick Ultra kit resulted in efficient sEV isolation and detection of sEV-AnxA2 protein and mRNA compared to the ultracentrifugation method. The standardized method was applied to the twenty TNBC patient sera for sEV isolation. High levels of sEV-AnxA2 protein and/or mRNA were associated with stage 3 and above in TNBC. Four patients who responded to neoadjuvant chemotherapy had high expression of AnxA2 protein and/or mRNA in sEVs, while other four who did not respond to chemotherapy had low levels of AnxA2 protein and mRNA in sEVs. Our data suggest that the sEV-AnxA2 protein and mRNA could be a combined predictive biomarker for responsiveness to chemotherapy in aggressive TNBC.

Short peptides based on the conserved regions of MIEN1 protein exhibit anticancer activity by targeting the MIEN1 signaling pathway

“…Subsequently, 18S was used as the reference gene for the mRNA levels. Relative change in gene expression was calculated according to the ΔΔCt method ( 53 , 54 ).…”

Translational implications of targeting annexin A2: From membrane repair to muscular dystrophy, cardiovascular disease and cancer

“…Annexin A2 is associated with metastasis in triple-negative breast cancer cells. 53 To spread beyond the primary tumour, tumour cells must degrade the extracellular matrix. Enhanced extracellular matrix degradation can be driven by plasminogen activation by F I G U R E 3 Annexin A2 promotes cancer.…”

“…Finally, extracellular annexin A2 enhances tumour metastasis. Annexin A2 is associated with metastasis in triple‐negative breast cancer cells 53 . To spread beyond the primary tumour, tumour cells must degrade the extracellular matrix.…”

RNA-binding is an ancient trait of the Annexin family

“…All Anxs, except AnxA9 and AnxA10, have so far been found in exosomes (http://www.exocarta.org/) (Gurung et al, 2021). AnxA2 is the best characterized member of the Anx family both in terms of its association with mRNA (Vedeler and Hollas, 2000;Vedeler et al, 2012;Strand et al, 2021;Grindheim et al, 2023) and exosomes (Valapala and Vishwanatha, 2011;Desai et al, 2022). AnxA2 appears to play a role in loading RNA cargo into exosomes (Monastyrskaya, 2018).…”

“…AnxA2 appears to play a role in loading RNA cargo into exosomes (Monastyrskaya, 2018). Regulatory RNAs that bind to the regulatory regions of anxA2 mRNA as well as anxA2 mRNA are incorporated into exosomes together with AnxA2 (Monastyrskaya, 2018;Desai et al, 2022) strongly suggesting that exosomes carry information to regulate the expression of AnxA2 in the recipient cell(s) since anxA2 mRNA binds to its cognate protein (Hollas et al, 2006). At present, the functional role of the other Anxs associating with exosomes has not been elucidated.…”