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In this paper we compare electrochemical behavior of two homolog proteins, namely anterior gradient 2 (AGR2) and anterior gradient 3 (AGR3), playing an important role in cancer cell biology. The slight variation in their protein structures has an impact on protein adsorption and orientation at charged surface and also enables AGR2 and AGR3 to form heterocomplexes. We confirm interaction between AGR2 and AGR3 (i) in vitro by immunochemical and constant current chronopotentiometric stripping (CPS) analysis and (ii) in vivo by bioluminescence resonance energy transfer (BRET) assay. Mutation of AGR2 in dimerization domain (E60A) prevents development of wild type AGR2 dimers and also negatively affects interaction with wild type AGR3 as shown by CPS analysis. Beside new information about AGR2 and AGR3 protein including their joint interaction, our work introduces possible applications of CPS in bioanalysis of protein complexes, including those relatively unstable, but important in the cancer research., Competing Interests: Declaration of Competing Interest The authors declared that there is no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Cervical cancer is one of the most common malignancies in women. MicroRNAs (miRNAs) are involved in a variety of fundamental cellular processes, including carcinogenesis. The potential utilization of aberrantly expressed miRNAs as novel biomarkers in cervical cancer diagnostics is growing. We investigated miRNA expression profiles during the progression of dysplasia in cervical epithelium to identify aberrantly expressed miRNAs. High-throughput miRNA profiling of high-grade precancerous lesions identified 79 miRNAs showing significant difference in expression values compared to normal cervical epithelium. Ten selected miRNAs were subsequently measured in an independent group of samples to validate them as promising biomarkers of cervical carcinogenesis. MicroRNAs miR-10b-5p, miR-34c-5p, miR-409-3p and miR-411-5p were confirmed as downregulated, while miR-10a-5p, miR-132-3p, miR-141-5p were significantly upregulated in dysplastic cervical tissues. Further investigation revealed an inverse correlation of miR-409-3p with E6 mRNA levels in precancerous cervical lesions. Subsequent in vitro analyses showed a direct involvement of this miRNA in the regulation of E6 oncogene levels, thus confirming a potential tumor suppressor function of miR-409-3p in cervical malignancies. Hence, miR-409-3p may represent a useful early marker and a potential therapeutic target for cervical cancer., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Expression of the AGR2 oncogene was shown to be associated with estrogen receptor positive tumors. This gene contributes to enhanced cellular proliferation, drug resistance, metastasis development and may also serve as a predictor of poor prognosis. However, our analysis of AGR2 expression in a subset of estrogen-receptor negative tumors revealed that AGR2 could also be upregulated in hormone-independent manner. AGR2 expression was shown to be significantly increased in HER2 positive breast tumors on both the mRNA and the protein level. Moreover, in a subset of estrogen- and progesterone-receptor negative and simultaneously HER2-positive cases, increased AGR2 expression significantly correlated with worse patient prognosis. Subsequent analysis of independent data sets either collected in our institute or obtained from Oncomine cancer microarray database confirmed all these findings., (Copyright © 2017 Elsevier Inc. All rights reserved.)