5460

POU5F1

POU class 5 homeobox 1;POU5F1;POU class 5 homeobox 1

POU domain transcription factor OCT4|POU domain, class 5, transcription factor 1|POU-type homeodomain-containing DNA-binding protein|octamer-binding protein 3|octamer-binding protein 4|octamer-binding transcription factor 3

6p21.31

protein-coding

In order to detect the expression of Oct4 in bladder cancer tissue and cell line BIU-87, immunohistochemistry was used in 49 bladder cancer biopsy samples and immunofluorescence and reverse transcription-PCR were performed on bladder cancer cell line BIU-87. Forty of 49 bladder cancer samples showed the expression of Oct4 in about 0.6% cancer cells. The positive rate and density of Oct4 expression had no obvious relationship with the grade, recurrence or metastasis of bladder cancer (P>0.05). A few Oct4 positive cells were found in bladder cancer cell line BIU-87, which was also confirmed by RT-PCR. This study indicated the existence of few Oct4 positive cells in bladder cancer, which may be the bladder cancer stem cells. This study may provide the foundation for isolation and identification of bladder cancer stem cells.

OBJECTIVE: To study the expression of OCT4 protein in bladder cancer and its correlation to the clinicopathologic features and prognosis of bladder cancer. METHODS: OCT4 mRNA and protein expression was detected in 5 bladder cancer cell lines (RT-4, Tcc-Sup, KK47, T24, and 5637) and 1 normal bladder cell lines by real-time PCR and Western blotting, respectively. Immunohistochemical analysis was used to detect the expression of OCT4 protein in 46 bladder cancer samples. RESULTS: All the 5 bladder cancer cell lines expressed detectable levels of OCT4 mRNA and proteins, whereas the normal bladder cell line SV-HUC-1 was negative for OCT4 expression. The clinical bladder cancer tissues showed a high positivity rate of OCT4 expression (76.1%), which was not detected in normal bladder tissues. Specific OCT-4 signals were localized mainly in the nuclei of the cancer cells. The expression rate of OCT4 protein was significantly higher in bladder cancer tissue than in normal bladder epithelium (P<0.05), and showed a positive correlation to the grade of tumor differentiation and metastasis (P<0.05) but not to the patients' age, gender or TNM stage. CONCLUSION: OCT4 protein expression is associated with tumor differentiation and metastasis in bladder cancer and may play an important role in the early diagnosis and prognostic evaluation of bladder cancer.

The stem cell-related transcription factor Oct4 regulates tumor proliferation and apoptosis, but its role in tumor migration and invasion is still undefined. Here, we compared Oct4 expression in MCF-7 and MDA-MB-231 cells, two breast cancer cell lines with similar epithelial origins, but distinct invasive and metastatic characteristics. We found MCF-7 cells to express very high levels of Oct4, while no obvious expression was detected in MDA-MB-231 cells. We then downregulated Oct4 expression using small interfering RNA (siRNA) to explore its effects on migration and invasion. Transwell assays showed that silencing Oct4 in MCF-7 cells improved their migration and invasion capabilities. Reverse-transcriptase PCR and western blots showed that E-cadherin expression decreased, and alpha-smooth muscle actin expression increased with Oct4 downregulation, which suggests that epithelial-to-mesenchymal transition (EMT) occurred. A potent EMT stimulus, TGF-beta1, significantly inhibited Oct4 expression in both dose- and time course-dependent manners. Silencing Oct4 also upregulated expression of two major components of store-operated Ca(2+) entry channels (SOCs), STIM1 and Orai1, and enhanced SOC-directed Ca(2+) influx. Silencing STIM1 blocked the Ca(2+) influx and rescued the EMT initiated by Oct4 downregulation. In conclusion, silencing Oct4 promotes invasion and metastasis in breast cancer cells by inducing EMT. This effect may be related to SOCs-directed enhancement of Ca(2+) influx.

PSCA and Oct-4 have been thought as markers of cancer stem cells. Although overexpression of PSCA and Oct-4 in cancer has been reported, little is known about the clinical and pathological significance with PSCA and Oct-4 expression in gallbladder adenocarcinoma. In this study, overexpression of PSCA and Oct-4 was detected in gallbladder adenocarcinoma (54.6% and 55.6%). Less expression of PSCA and Oct-4 was detected in the pericancerous tissues (19.6% and 21.7%), gallbladder polyps (13.3% and 13.3%), and gallbladder epithelium with chronic cholecystitis (14.3% and 14.3%). The overexpression of PSCA and Oct-4 was significantly associated with differentiation, tumor mass, lymph node metastasis, invasion of gallbladder adenocarcinoma, and decreased overall survival. Our study suggested that overexpression of PSCA and Oct-4 might be closely related to the carcinogenesis, progression, metastasis, or invasive potential and prognosis of gallbladder carcinoma.

Epithelial-mesenchymal transition (EMT), a critical process of cancer invasion and metastasis, is associated with stemness property of cancer cells. Though Oct4 and Nanog are homebox transcription factors essential to the self-renewal of stem cells and are expressed in several cancers, the role of Oct4/Nanog signaling in tumorigenesis is still elusive. Here microarray and quantitative real-time PCR analysis showed a parallel, elevated expression of Oct4 and Nanog in lung adenocarcinoma (LAC). Ectopic expressions of Oct4 and Nanog in LACs increased the percentage of CD133-expressing subpopulation and sphere formation, enhanced drug resistance, and promoted EMT. Ectopic expressions of Oct4 and Nanog activated Slug and enhanced the tumor-initiating capability of LAC. Furthermore, double knockdown of Oct4 and Nanog suppressed the expression of Slug, reversed the EMT process, blocked the tumorigenic and metastatic ability, and greatly improved the mean survival time of transplanted immunocompromised mice. The immunohistochemical analysis demonstrated that expressions of Oct4, Nanog, and Slug were present in high-grade LAC, and triple positivity of Oct4/Nanog/Slug indicated a worse prognostic value of LAC patients. Our results support the notion that the Oct4/Nanog signaling controls epithelial-mesenchymal transdifferentiation, regulates tumor-initiating ability, and promotes metastasis of LAC.

BACKGROUND: In recent years, cases of lung adenocarcinoma morbidity have consistently grown. OCT4 is the key gene that controls the automatic renewal of stem cells, and regulates the proliferation and differentiation of cancer stem cells. The aim of this study is to detect OCT4 expression in lung adenocarcinoma tissues, and to evaluate its relevance in the metastasis, chemotherapeutic effect, and prognosis in lung adenocarcinoma patients. METHODS: Immunofluorescence method was employed to detect OCT4 expression in lung adenocarcinoma tissues. The relationship between OCT4 expression and clinical pathological indicators is examined through chi-square test. Moreover, the survival rate is calculated through the Kaplan-Meier survivorship curve. Finally, the relevance between the indicators and patient survival is estimated using Cox analysis. RESULTS: Among the 126 tissue samples of lung adenocarcinoma, 91 showed OCT4 positive cells. OCT4 expression is closely related to metastasis and chemoresistance in lung adenocarcinoma patients, and negatively corresponds to the patients' disease-free survival and survival periods. CONCLUSIONS: OCT4 expression is related to metastasis and chemoresistance in lung adenocarcinoma patients, and thus indicates poor prognosis.

OBJECTIVE: To discuss the meanings of Oct-4's expression in thyroid adenoma, thyroid papillary carcinoma, thyroid follicular carcinoma, and medullary thyroid carcinoma. METHOD: We examined the expression of Oct-4 in 15 thyroid adenoma, 30 thyroid papillary carcinomas, 2 thyroid follicular carcinomas, and 3 medullary thyroid carcinomas using immunofluorescence. RESULT: Oct-4 expression was observed in all the thyroid-related diseases mentioned above. In thyroid papillary carcinomas, the expression of Oct-4 were higher than that in thyroid adenoma, and had no obvious relationship with the patients age, sex, the size and location of tumor and tumor metastasis. CONCLUSION: The formation of the thyroid carcinomas may be concerned with the stem cells in thyroid. There are more stem cells in medullary thyroid carcinomas and follicular carcinomas.