Elsevier BV Acta Medica Okayama 2589-0042 29 4 2026 Multifaceted role of POU5F1P1 in regulating its parental stem cell gene, POU5F1 115137 EN Kyohei Irie Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Mitsuko Kosaka Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Nobuhiko Mizuno Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Omae Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshimasa Nakatani Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Sandi Myat Noe Oo Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hisashi Masuyama Department of Obstetrics and Gynecology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ayano Kawaguchi Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences The human-specific retrogene POU5F1P1 (OCT4-Pseudogene1; OCT4-PG1), derived from stem cell factor POU5F1 (OCT4A), is predicted to encode an OCT4A-like protein; however, its function remains unclear. This study investigated OCT4-PG1 expression, translational control, and its role in endometrial cancer and stem cell regulation. Quantitative analyses revealed that elevated OCT4A, but not OCT4-PG1, expression correlated with clinical risk factors associated with poor prognosis in patients with endometrial cancer. OCT4-PG1 is under strong translational suppression mediated by its untranslated region and does not function as a protein under normal conditions. Instead, it acts as a non-coding RNA that suppresses OCT4A translation. Structural analyses showed that a single amino acid deletion (Gln259) destabilizes the OCT4-PG1 protein, thereby preventing its tumorigenic and transcriptional functions. Nevertheless, OCT4-PG1 forms heterodimers with OCT4A or SOX2, enhancing the regulatory activity of OCT4A. These findings highlight the regulatory role of pseudogenes in cancer and stem cell biology, with implications for therapies targeting OCT4A-related pathways. No potential conflict of interest relevant to this article was reported.

BMC Acta Medica Okayama 1471-2407 20 1 2020 Prognostic value of OCT4A and SPP1C transcript variant co-expression in early-stage lung adenocarcinoma 521 EN Seijiro Koshimune Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Mitsuko Kosaka Okayama Univ, Dept Human Morphol, Grad Sch Med Dent & Pharmaceut Sci Nobuhiko Mizuno Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hiromasa Yamamoto Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomoyuki Miyamoto Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kohta Ebisui Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shinichi Toyooka Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Aiji Ohtsuka Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Background</br> Octamer-binding transcription factor 4A (OCT4A) is essential for cell pluripotency and reprogramming both in humans and mice. To date, however, the function of human OCT4 in somatic and/or tumour tissues is largely unknown.</br> Methods</br> RT-PCR was used to identify full-length splice forms of OCT4 transcripts in normal and cancer cells. A FLAG-tagged OCT4 genomic transgene was used to identify OCT4-positive cancer cells. A potential role for OCT4 in somatic cancer cells was examined by cell ablation of OCT4-positive cells using promoter-driven diphtheria toxin A. OCT4 and secreted phosphoprotein 1 (SPP1) transcripts in early-stage lung adenocarcinoma tumours were analysed and compared with pathohistological features.</br> Results</br> The results show that, unlike in murine cells, OCT4A and OCT4B variants are transcribed in both human cancer cells and in adult tissues such as lung, kidney, uterus, breast, and eye. We found that OCT4A and SPP1C are co-expressed in highly aggressive human breast, endometrial, and lung adenocarcinoma cell lines, but not in mesothelial tumour cell lines. Ablation of OCT4-positive cells in lung adenocarcinoma cells significantly decreased cell migration and SPP1C mRNA levels. The OCT4A/SPP1C axis was found in primary, early-stage, lung adenocarcinoma tumours.</br> Conclusions</br> Co-expression of OCT4 and SPP1 may correlate with cancer aggressiveness, and the OCT4A/SPP1C axis may help identify early-stage high-risk patients with lung adenocarcinoma. Contrary to the case in mice, our data strongly suggest a critical role for OCT4A and SPP1C in the development and progression of human epithelial cancers. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 1431-9276 19 2 2013 Architecture of the Subendothelial Elastic Fibers of Small Blood Vessels and Variations in Vascular Type and Size 406 414 EN Akira Shinaoka Ryusuke Momota Eri Shiratsuchi Mitsuko Kosaka Kanae Kumagishi Ryuichi Nakahara Ichiro Naito Aiji Ohtsuka Most blood vessels contain elastin that provides the vessels with the resilience and flexibility necessary to control hemodynamics. Pathophysiological hemodynamic changes affect the remodeling of elastic components, but little is known about their structural properties. The present study was designed to elucidate, in detail, the three-dimensional (3D) architecture of delicate elastic fibers in small vessels, and to reveal their architectural pattern in a rat model. The fine vascular elastic components were observed by a newly developed scanning electron microscopy technique using a formic acid digestion with vascular casts. This method successfully visualized the 3D architecture of elastic fibers in small blood vessels, even arterioles and venules. The subendothelial elastic fibers in such small vessels assemble into a sheet of meshwork running longitudinally, while larger vessels have a higher density of mesh and thicker mesh fibers. The quantitative analysis revealed that arterioles had a wider range of mesh density than venules; the ratio of density to vessel size was higher than that in venules. The new method was useful for evaluating the subendothelial elastic fibers of small vessels and for demonstrating differences in the architecture of different types of vessels. No potential conflict of interest relevant to this article was reported.