Expression of OCT4A: the first step to the next stage of urothelial bladder cancer progression

Linc-ROR has a Potential ceRNA Activity for OCT4A by Sequestering miR-335-5p in the HEK293T Cell Line

Linc-ROR has a regulatory role in reprogramming, and the core stem cell transcription factors, OCT4, SOX2, and NANOG, regulate its expression. MicroRNAs (miRNAs) are also a critical constituent of pivotal posttranscriptional regulatory pathways. One of such interactions is a competing endogenous RNA interaction that connects small and long non-coding RNAs with coding transcripts. Here, we aimed to investigate the existence of such associations between OCT4A, Linc-ROR, hsa-miR-335-5p, and hsa-miR-544. Bioinformatic analysis was performed to evaluate the expression status of OCT4A, Linc-ROR, miR-335, and miR-544 throughout differentiation as well as in various differentiated cells. The complete lengths of OCT4A and Linc-ROR, and OCT4A 3'-UTR were cloned in the luciferase reporter vector, and the precursors of miR-335 and miR-544 were cloned in expression vectors. Following the overexpression of miR-335 and miR-544 in the 5637 cell line, the endogenous expression of OCT4A and Linc-ROR was evaluated. Afterward, the expression vectors of miRNAs and the reporter vectors of OCT4A/Linc-ROR were co-transfected in the HEK293T cell line. Via the Dual-Luciferase assay, the effect of the overexpression of miRNAs on their two possible targets (Linc-ROR and OCT4A) was investigated. The bioinformatic analysis demonstrated a relatively similar expression pattern for OCT4A and Linc-ROR, while miR-335 showed a different expression status. Both miR-335 and miR-544 inhibited the endogenous expression of OCT4A. The Dual-Luciferase assay likewise confirmed the inhibitory effect of miR-335 and miR-544 on OCT4A expression. In contrast, the miR-335 inhibitory effect was reversed in the presence of Linc-ROR, resulting in the upregulation of OCT4A. Such evidence suggests that Linc-ROR may compete with OCT4A to interact with miR-335.

FUS-dependent loading of SUV39H1 to OCT4 pseudogene-lncRNA programs a silencing complex with OCT4 promoter specificity

The resurrection of pseudogenes during evolution produced lncRNAs with new biological function. Here we show that pseudogene-evolution created an Oct4 pseudogene lncRNA that is able to direct epigenetic silencing of the parental Oct4 gene via a 2-step, lncRNA dependent mechanism. The murine Oct4 pseudogene 4 (mOct4P4) lncRNA recruits the RNA binding protein FUS to allow the binding of the SUV39H1 HMTase to a defined mOct4P4 lncRNA sequence element. The mOct4P4-FUS-SUV39H1 silencing complex holds target site specificity for the parental Oct4 promoter and interference with individual components results in loss of Oct4 silencing. SUV39H1 and FUS do not bind parental Oct4 mRNA, confirming the acquisition of a new biological function by the mOct4P4 lncRNA. Importantly, all features of mOct4P4 function are recapitulated by the human hOCT4P3 pseudogene lncRNA, indicating evolutionary conservation. Our data highlight the biological relevance of rapidly evolving lncRNAs that infiltrate into central epigenetic regulatory circuits in vertebrate cells.

Co-Expression of Stem Cell and Epithelial Mesenchymal Transition Markers in Circulating Tumor Cells of Bladder Cancer Patients

Objective

Cancer cells with stemness and epithelial-to-mesenchymal transition (EMT) features display enhanced malignant and metastatic potential. This study aimed to introduce a new methodology developed in order to investigate the co-expression of a stemness (OCT4) and EMT markers on single circulating tumor cells (CTCs) of patients with localized urinary bladder cancer and their potential prognostic prediction value.

Methods and Materials

Between April 2015 and July 2015, blood samples of 51 consecutive patients diagnosed with high risk bladder cancer (cT_1-3N₀M₀) were prospectively investigated for CTCs. Peripheral blood (5 mL) was drawn before primary transurethral resection. Detection of CTCs was performed using the CanPatrol^TM system. Nucleic acid probes were used to identify CTCs, and expression levels of epithelial and mesenchymal genes in CTCs were examined by situ hybridization assay.

Results

All patients received radical cystectomy with pelvic lymph nodes dissection. CTCs were detected in 44 of 51 (86.3%) patients, respectively. The overall mean number of CTCs was 6.1 (range: 0~29; median: 4). A total of 311 CTCs were detected in PB. High OCT4 expression (OCT4^high) was detected more frequently in Epi⁻Mes⁺ cells (p=0.001). Patients with pathological confirmed muscle-invasive bladder cancer (MIBC) had higher Epi⁻Mes⁺ CTCs positive rates (p=0.001) and OCT4^high CTCs positive rates (p=0.019) than pathological confirmed non muscle-invasive bladder cancer (NMIBC). Regarding co-expression of these markers, Epi⁻Mes⁺/OCT4^high CTCs were more frequently evident in the MIBC setting (30.4% vs 3.6% of patients, p = 0.016).

Conclusion

A differential expression pattern for these markers was observed both in NMIBC and MIBC disease. A subgroup of CTCs showed a CTCs expressing high OCT4, along with Mes were more frequently detected in patients with MIBC, suggesting that these cells may prevail during tumor muscle invasion and disease progression.

Clinicopathological and prognostic significance of OCT4 in patients with hepatocellular carcinoma: a meta-analysis

Background and aims

Octamer-binding transcription factor 4 (OCT4) has been implicated in the development of hepatocellular carcinoma (HCC), although the findings are controversial. We conducted a meta-analysis to assess the correlation between OCT4 and the clinicopathological characteristics and the prognostic value in HCC.

Methods

An electronic search for relevant articles was conducted in PubMed, Cochrane Library, Web of Science, EMBASE database, Chinese CNKI, and Chinese WanFang database. Correlations between OCT4 expression and clinicopathological features and survival outcomes were analyzed. Pooled odds ratios and hazard ratios with 95% CIs were calculated using STATA 14.2 software.

Results

A total of 10 trials with 985 patients were included. Positive OCT4 expression was correlated with tumor size, tumor numbers, differentiation, and TNM stage. OCT4 expression was not correlated with gender, age, hepatitis B surface antigen, alfa-fetoprotein, liver cirrhosis, vascular invasion, or tumor encapsulation. OCT4 expression was associated with poor 3- and 5-year overall survival, and disease-free survival rate.

Conclusion

OCT4 expression was associated with tumor size, tumor numbers, differentiation, and TNM stage in HCC. OCT4 may be a useful prognostic biomarker for HCC.

Expression and Prognostic Value of Oct-4 in Astrocytic Brain Tumors

Background

Glioblastomas are the most frequent type of malignant primary brain tumor with a median overall survival less than 15 months. Therapy resistance of glioblastomas has been attributed to the presence of tumor initiating stem-like cells (TSCs). TSC-related markers have therefore been suggested to have promising potentials as prognostic markers in gliomas.

Methodology/Principal Findings

The aim of the present study was to investigate the expression and prognostic impact of the TSC-related marker Oct-4 in astrocytic brain tumors of increasing grade. In total 114 grade II, III and IV astrocytic brain tumors were immunohistochemically stained for Oct-4, and the fraction and intensity of Oct-4 positive cells were determined by morphometric analysis of full tumor sections. Oct-4 was expressed in all tumors, and the Oct-4 positive cell fraction increased with tumor grade (p = 0.045). There was no association between survival and Oct-4 positive cell fraction, neither when combining all tumor grades nor in analysis of individual grades. Oct-4 intensity was not associated with grade, but taking IDH1 status into account we found a tendency for high Oct-4 intensity to be associated with poor prognosis in anaplastic astrocytomas. Double immunofluorescence stainings showed co-localization in the perivascular niches of Oct-4 and two other TSC markers CD133 and nestin in glioblastomas. In some areas Oct-4 was expressed independently of CD133 and nestin.

Conclusions

In conclusion, high Oct-4 fraction was associated with tumor malignancy, but seemed to be without independent prognostic influence in glioblastomas. Identification of a potential prognostic value in anaplastic astrocytomas requires additional studies using larger patient cohorts.

Transcription factor Oct4 promotes osteosarcoma by regulating lncRNA AK055347

Osteosarcoma is the most common primary bone tumor in children and adolescents, typically presenting with a poor prognosis. Octamer-binding transcription factor 4 (Oct4) protein, encoded by the POU class 5 homeobox 1 gene, is important in maintaining self-renewal of pluripotent stem cells, and is closely associated with cancer. However, its role in osteosarcoma remains to be elucidated. The present study observed Oct4 was markedly increased in osteosarcoma cell lines and in human osteosarcoma tissue samples. Following Oct4 downregulation by small interfering RNA (siRNA) in osteosarcoma F5M2 cells, the cells exhibited significant decreases in proliferation and invasion ability, and an increase in cell apoptosis. Notably, downregulation of Oct4 decreased the expression of AK055347, a newly identified long noncoding RNA (lncRNA) in human tissues. The downregulation of AK055347 by siRNA resulted in a significant suppressive effect on proliferative and invasive ability, and promotion of cell apoptosis in osteosarcoma cells. Thus, the current study suggests Oct4 exerts a promoting effect in osteosarcoma, and identifies a novel lncRNA in osteosarcoma progression.

Functional and molecular characterization of cancer stem-like cells in bladder cancer: a potential signature for muscle-invasive tumors

Striking evidence associates cancer stem cells (CSCs) to the high recurrence rates and poor survival of patients with muscle-invasive bladder cancer (BC). However, the prognostic implication of those cells in risk stratification is not firmly established, mainly due to the functional and phenotypic heterogeneity of CSCs populations, as well as, to the conflicting data regarding their identification based on a single specific marker. This emphasizes the need to exploit putative CSC-related molecular markers with potential prognostic significance in BC patients.

This study aimed to isolate and characterize bladder CSCs making use of different functional and molecular approaches. The data obtained provide strong evidence that muscle-invasive BC is enriched with a heterogeneous stem-like population characterized by enhanced chemoresistance and tumor initiating properties, able to recapitulate the heterogeneity of the original tumor. Additionally, a logistic regression analysis identified a 2-gene stem-like signature (SOX2 and ALDH2) that allows a 93% accurate discrimination between non-muscle-invasive and invasive tumors.

Our findings suggest that a stemness-related gene signature, combined with a cluster of markers to more narrowly refine the CSC phenotype, could better identify BC patients that would benefit from a more aggressive therapeutic intervention targeting CSCs population.

Epithelial plasticity in urothelial carcinoma: Current advancements and future challenges

Urothelial carcinoma (UC) of the bladder is characterized by high recurrence rate where a subset of these cells undergoes transition to deadly muscle invasive disease and later metastasizes. Urothelial cancer stem cells (UroCSCs), a tumor subpopulation derived from transformation of urothelial stem cells, are responsible for heterogeneous tumor formation and resistance to systemic treatment in UC of the bladder. Although the precise reason for pathophysiologic spread of tumor is not clear, transcriptome analysis of microdissected cancer cells expressing multiple progenitor/stem cell markers validates the upregulation of genes that derive epithelial-to-mesenchymal transition. Experimental studies on human bladder cancer xenografts describe the mechanistic functions and regulation of epithelial plasticity for its cancer-restraining effects. It has been further examined to be associated with the recruitment of a pool of UroCSCs into cell division in response to damages induced by adjuvant therapies. This paper also discusses the various probable therapeutic approaches to attenuate the progressive manifestation of chemoresistance by co-administration of inhibitors of epithelial plasticity and chemotherapeutic drugs by abrogating the early tumor repopulation as well as killing differentiated cancer cells.

Epithelial plasticity in urothelial carcinoma: Current advancements and future challenges

Urothelial carcinoma (UC) of the bladder is characterized by high recurrence rate where a subset of these cells undergoes transition to deadly muscle invasive disease and later metastasizes. Urothelial cancer stem cells (UroCSCs), a tumor subpopulation derived from transformation of urothelial stem cells, are responsible for heterogeneous tumor formation and resistance to systemic treatment in UC of the bladder. Although the precise reason for pathophysiologic spread of tumor is not clear, transcriptome analysis of microdissected cancer cells expressing multiple progenitor/stem cell markers validates the upregulation of genes that derive epithelial-to-mesenchymal transition. Experimental studies on human bladder cancer xenografts describe the mechanistic functions and regulation of epithelial plasticity for its cancer-restraining effects. It has been further examined to be associated with the recruitment of a pool of UroCSCs into cell division in response to damages induced by adjuvant therapies. This paper also discusses the various probable therapeutic approaches to attenuate the progressive manifestation of chemoresistance by co-administration of inhibitors of epithelial plasticity and chemotherapeutic drugs by abrogating the early tumor repopulation as well as killing differentiated cancer cells.

Frequency of CD4+CD25+Foxp3+ cells in peripheral blood in relation to urinary bladder cancer malignancy indicators before and after surgical removal

Tumor cells communicate with stromal cells, including cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs), to form microenvironment inhibiting immune responses. Regulatory T cells (Tregs, CD4+CD25+FoxP3+) stimulate immune tolerance and facilitate tumor progression. We analyzed the changes in Treg frequencies assessed using flow cytometry in the peripheral blood of patients with urothelial bladder cancer before and after tumor-removal. Changes in Treg frequency were investigated in relation to clinicopathomorphological indicators of tumor malignancy and expression of RCAS1 on CAFs and TAMs. Higher Treg frequencies were observed in early phase of tumor growth (pTa-pT2), in larger tumors, with more aggressive type of invasion, and with expression of RCAS1. The later phase of tumor development, accompanied by a nonclassic differentiations and pT3-pT4 advancement, had lower number of tumor infiltrating lymphocytes (TILs) and lower Treg frequency. Furthermore, in pT2-pT4 tumors, a decreased post-surgery Treg frequency was associated with poorer prognosis: patients with the lowest frequency of Tregs died first. These findings strongly suggest that the Treg frequencies at later phase of tumor growth, associated with a low anti-tumor response, represent a new and important prognostic indicator in urinary bladder cancer.

Changes in Immunogenicity during the Development of Urinary Bladder Cancer: A Preliminary Study

In the present study, we evaluated tumor-infiltrating lymphocytes (TILs) and blood regulatory T lymphocyte (Tregs, CD4+/CD25+/FoxP3+) expression in bladder cancer patients. The number of CD4+, CD8+, CD25+, FoxP3+ and CD20+ TILs was analyzed in association with clinico-pathomorphological features. In more advanced metastasizing tumors, showing non-classic differentiation (ND) and a more aggressive tissue invasion type (TIT), the number of TILs decreased. A low number of CD4+ TILs was associated with poor prognosis. Similarly, Treg frequency before surgery and after surgical treatment was significantly lower in more advanced tumors. The changes in TILs, as well as of local and systemic Tregs, were accompanied by changes in the histological phenotype of urothelial carcinoma regarding pT stage, NDs, TIT, and clinical outcomes. The number of TILs and the frequency of blood Tregs (indicators of antitumor response) may be essential for choosing an immunotherapy that is adjusted to the immune status according to the phase of tumor growth. Moreover, a significant reduction in the number of CD4+ and CD8+ TILs with the development of NDs in more advanced tumors may be associated with lower tumor immunogenicity, resulting in immune tolerance towards tumor tissue. These observations and the tendency of urothelial bladder carcinoma to undergo NDs in a heterogeneous manner during tumor progression suggest complex interactions between bladder cancer immunogenicity and stages of tumor progression.

Key signaling pathways in the muscle-invasive bladder carcinoma: Clinical markers for disease modeling and optimized treatment

In this review, we evaluate key molecular pathways and markers of muscle-invasive bladder cancer (MIBC). Overexpression and activation of EGFR, p63, and EMT genes are suggestive of basal MIBC subtype generally responsive to chemotherapy. Alterations in PPARγ, ERBB2/3, and FGFR3 gene products and their signaling along with deregulated p53, cytokeratins KRT5/6/14 in combination with the cellular proliferation (Ki-67), and cell cycle markers (p16) indicate the need for more radical treatment protocols. Similarly, the "bell-shape" dynamics of Shh expression levels may suggest aggressive MIBC. A panel of diverse biological markers may be suitable for simulation studies of MIBC and development of an optimized treatment protocol. We conducted a critical evaluation of PubMed/Medline and SciFinder databases related to MIBC covering the period 2009-2015. The free-text search was extended by adding the following keywords and phrases: bladder cancer, metastatic, muscle-invasive, basal, luminal, epithelial-to-mesenchymal transition, cancer stem cell, mutations, immune response, signaling, biological markers, molecular markers, mathematical models, simulation, epigenetics, transmembrane, transcription factor, kinase, predictor, prognosis. The resulting selection of ca 500 abstracts was further analyzed in order to select the latest publications relevant to MIBC molecular markers of immediate clinical significance.

Expression of Vitamin D Receptor (VDR) Positively Correlates with Survival of Urothelial Bladder Cancer Patients

Vitamin D3 shows tumoristatic and anticancer effects by acting through the vitamin D receptor (VDR), while hydroxylation of 25-hydroxyvitamin D3 at position 1α by CYP27B1 is an essential step in its activation. The expression of both the VDR and CYP27B1 has been found in many normal and cancer tissues, but there is a lack of information about its expression in human bladder cancers. The aim of the present research was to examine whether the expression of the VDR and CYP27B1 in bladder cancer was related to the prognostic markers and disease outcome. We analyzed VDR and CYP27B1 in samples of tumor and normal tissues obtained from 71 urinary bladder cancer patients. The highest VDR immunostaining was found in normal epithelium and was significantly lower in bladder cancer cells (p < 0.001 with Mann–Whitney U test). VDR expression was lowest in more advanced (pT2b–pT4) (p = 0.005 with Mann–Whitney U test) and metastasizing cancers (p < 0.05 and p = 0.004 with Mann–Whitney U test for nuclear and cytoplasmic VDR immunostaining, respectively). The lack of cytoplasmic and nuclear VDR was also related to shorter overall survival (for cytoplasmic VDR immunolocalization 13.3 vs. 55.3 months of survival, HR = 1.92, p = 0.04 and for nuclear VDR immunostaining 13.5 vs. 55.3 months of survival, HR = 2.47, p = 0.002 with Mantel-Cox test). In cases with the lack of high cytoplasmic VDR staining the non-classic differentiations (NDs) was observed in higher percentage of tumor area. CYP27B1 expression was lower in cancer cells than in normal epithelial cells (p = 0.03 with Mann–Whitney U test), but its expression did not correlate with tumor stage (pT), metastasizing, grade, mitotic activity or overall survival. In conclusion, expression of the VDR and CYP27B1 are deregulated in urothelial bladder cancers. Although our results showing a relationship between the decreased VDR expression and prognostic markers and survival time indicate potential usefulness of VDR as a new indicator of a poorer prognosis, further studies are needed in different patient cohorts by independent groups to validate this hypothesis. We also suggest that vitamin D-based therapies may represent an adjuvant strategy in treatment for bladder cancers expressing VDR.

Expression of RCAS1 correlates with urothelial bladder cancer malignancy

RCAS1 is a protein that participates in regulation of the tumor microenvironment and its immune responses, all in order to evade the immune system. The aim of this study was to analyze RCAS1 expression in urothelial bladder cancer cells (and in fibroblasts and macrophages of the tumor stroma) and its relationship with the histological pattern of malignancy. Eighty-three postcystectomy patients were enrolled. We analyzed the histological maturity (grade), progress (pT stage), tissue invasion type (TIT), nonclassic differentiation number (NDN), and the ability to metastasize (pN). The expression of RCAS1 protein was analyzed by immunohistochemistry. Indicators of histological malignancy were observed solely in association with the RCAS1 expression in cells in the border parts (BPs) of the tumor. Histological malignancy of the tumor, indicated by the pT and pN, and metastasis-free survival time, correlated significantly with RCAS1 expression in tumor neoplastic cells, whereas malignancy determined by grade, TIT, and NDN correlated with RCAS1 expression in fibroblasts and macrophages in the tumor microenvironment. These findings suggest that the increased RCAS1 expression depends on its cellular source and that RCAS1 expression itself is a component of various signaling pathways. The immune escape occurs within the tumor BPs, where the increase in the RCAS1 expression occurs within tumor cells and stromal cells in its microenvironment. We conclude that the histological pattern of tumor malignancy, indicated by grade, TIT, NDN, pT, and pN is a morphological indicator of immune escape.