{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:07:16Z","timestamp":1792789636637,"version":"4.5.0"},"reference-count":31,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T00:00:00Z","timestamp":1790640000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002657","name":"Istanbul University Scientific Research Projects Department","doi-asserted-by":"publisher","award":["32581"],"award-info":[{"award-number":["32581"]}],"id":[{"id":"10.13039\/501100002657","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002657","name":"Istanbul University Scientific Research Projects Department","doi-asserted-by":"publisher","award":["40170"],"award-info":[{"award-number":["40170"]}],"id":[{"id":"10.13039\/501100002657","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004410","name":"Scientific and Technological Research Council of T\u00fcrkiye","doi-asserted-by":"publisher","award":["122Z268"],"award-info":[{"award-number":["122Z268"]}],"id":[{"id":"10.13039\/501100004410","id-type":"DOI","asserted-by":"publisher"}]},{"name":"University of Pittsburgh Ovarian Cancer SPORE","award":["P50CA272218"],"award-info":[{"award-number":["P50CA272218"]}],"id":[{"id":"https:\/\/ror.org\/01an3r305","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Mol. Sci.","IJMS"],"abstract":"<jats:p>Ovarian cancer stem-like cells (OCSCs) are major drivers of tumor recurrence and chemoresistance. Although PIWI-interacting RNAs (piRNAs) have emerged as important regulators of cancer stem cell (CSC) biology, their roles in OCSCs remain poorly understood. We performed a systematic analysis of public datasets to identify ovarian cancer-associated piRNAs and selected piR-823 and piR-20326 for functional validation. Their expression was evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR)following piRNA mimic and inhibitor transfections in three-dimensional (3D) ovarian cancer spheroids and ALDH+\/CD133+ stem-like subpopulations isolated by fluorescence-activated cell sorting. Stemness-associated genes (ALDH1A1, ALDH1A2, ALDH1A3, SOX2, CD133, and NANOG) were analyzed, and The Cancer Genome Atlas (TCGA) transcriptomic data were used for clinical validation. Both piR-823 and piR-20326 were significantly enriched in spheroid cultures and ALDH+\/CD133+ populations, supporting their association with stem-like phenotypes. Functional analyses showed that piR-823 modulation was associated with changes in multiple stemness-related markers, whereas piR-20326 showed variable effects across two-dimensional (2D) and spheroid 3D culture models. TCGA data confirmed consistent co-expression patterns among stemness-related genes in clinical samples. These findings identify piR-823 as a key regulator and piR-20326 as a modulatory component of the piRNA-mediated stemness network in ovarian cancer, supporting further investigation of the piRNA\u2013stemness axis as a potential therapeutic target.<\/jats:p>","DOI":"10.3390\/ijms27198689","type":"journal-article","created":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T09:10:54Z","timestamp":1790673054000},"page":"8689","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["piR-823 and piR-20326 Differentially Regulate Stemness Programs in Ovarian Cancer Stem-like Cells"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3807-0330","authenticated-orcid":false,"given":"Ece","family":"Gumusoglu-Acar","sequence":"first","affiliation":[{"name":"Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Bozdogankemeri St., No. 1., 34134 Istanbul, Turkey"},{"name":"Magee-Womens Research Institute, Pittsburgh, PA 15213, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Sude Sultan","family":"Ozdemir","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Genetics, Institute of Graduate Studies in Sciences, Istanbul University, 34116 Istanbul, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-0708-1518","authenticated-orcid":false,"given":"Uygar","family":"Yucekaya","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Genetics, Institute of Graduate Studies in Sciences, Istanbul University, 34116 Istanbul, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5665-9790","authenticated-orcid":false,"given":"Ronald J.","family":"Buckanovich","sequence":"additional","affiliation":[{"name":"Magee-Womens Research Institute, Pittsburgh, PA 15213, USA"},{"name":"Department of Internal Medicine and Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3514-5210","authenticated-orcid":false,"given":"Tuba","family":"Gunel","sequence":"additional","affiliation":[{"name":"Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Bozdogankemeri St., No. 1., 34134 Istanbul, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1038\/s41571-024-00881-3","article-title":"Global epidemiology of epithelial ovarian cancer","volume":"21","author":"Webb","year":"2024","journal-title":"Nat. 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