NANOG regulates the proliferation of PCSCs via the TGF-β1/SMAD pathway

[High expression of the stemness-associated molecule Nanog in esophageal squamous cell carcinoma tissues promotes tumor invasion and metastasis by activating the TGF-β signaling pathway]

OBJECTIVE

To investigate the expression of Nanog and its regulatory relationship with MMP-2/MMP-9 proteins in esophageal squamous cell carcinoma (ESCC).

METHODS

We detected Nanog and MMP-2/MMP-9 protein expressions in 127 ESCC tissues and 82 adjacent normal tissues using immunohistochemistry and explored their correlations with the clinicopathological parameters and prognosis of the patients. GEO database was utilized to analyze the pathways enriched with the stemness-related molecules including Nanog, and TIMER online tool was used to analyze the correlations among TβR1, MMP-2, and MMP-9 in esophageal cancer.

RESULTS

Nanog and MMP-2/MMP-9 proteins were significantly upregulated in ESCC tissues and positively intercorrelated. Their expression levels were closely correlated with infiltration depth and lymph node metastasis of ESCC but not with age, gender, or tumor differentiation. The patients with high expressions of Nanog and MMP-2/MMP-9 had significantly shorter survival time. Bioinformatics analysis showed enrichment of stemness-associated molecules in the TGF-β signaling pathway, and the expressions of MMP-2/MMP-9 and TβR1 were positively correlated. In cultured ESCC cells, Nanog knockdown significantly decreased the expression of TβR1, p-Smad2/3, MMP-2, and MMP-9 and strongly inhibited cell migration.

CONCLUSION

The high expressions of Nanog, MMP-2, and MMP-9, which are positively correlated, are closely related with invasion depth, lymph node metastasis, and prognosis of ESCC. Nanog regulates the expressions of MMP-2/MMP-9 proteins through the TGF-β signaling pathway, and its high expression promotes migration of ESCC cells.

The Molecular Biology of Prostate Cancer Stem Cells: From the Past to the Future

Prostate cancer (PCa) continues to rank as the second leading cause of cancer-related mortality in western countries, despite the golden treatment using androgen deprivation therapy (ADT) or anti-androgen therapy. With decades of research, scientists have gradually realized that the existence of prostate cancer stem cells (PCSCs) successfully explains tumor recurrence, metastasis and therapeutic failure of PCa. Theoretically, eradication of this small population may improve the efficacy of current therapeutic approaches and prolong PCa survival. However, several characteristics of PCSCs make their diminishment extremely challenging: inherent resistance to anti-androgen and chemotherapy treatment, over-activation of the survival pathway, adaptation to tumor micro-environments, escape from immune attack and being easier to metastasize. For this end, a better understanding of PCSC biology at the molecular level will definitely inspire us to develop PCSC targeted approaches. In this review, we comprehensively summarize signaling pathways responsible for homeostatic regulation of PCSCs and discuss how to eliminate these fractional cells in clinical practice. Overall, this study deeply pinpoints PCSC biology at the molecular level and provides us some research perspectives.

Aquaporins as Prognostic Biomarker in Prostate Cancer

Prostate cancer is a complex heterogeneous disease that affects millions of males worldwide. Despite rapid advances in molecular biology and innovation in technology, few biomarkers have been forthcoming in prostate cancer. The currently available biomarkers for the prognosis of prostate cancer are inadequate and face challenges, thus having limited clinical utility. To date, there are a number of prognostic and predictive biomarkers identified for prostate cancer but lack specificity and sensitivity to guide clinical decision making. There is still tremendous scope for specific biomarkers to understand the natural history and complex biology of this heterogeneous disease, and to identify early treatment responses. Accumulative studies indicate that aquaporins (AQPs) a family of membrane water channels may serve as a prognostic biomarker for prostate cancer in monitoring disease advancement. In the present review, we discuss the existing prostate cancer biomarkers, their limitations, and aquaporins as a prospective biomarker of prognostic significance in prostate cancer.

Characterization of nanog in Nile tilapia (Oreochromis niloticus) and its spatiotemporal expression patterns during embryonic and gonadal development

Nanog is one of the well-characterized core transcription factors in pluripotency maintenance network. So far, studies on fishes indicate that the Nanog expression occurs from embryonic 1-cell stage to blastula stage, and is restricted to the gonadal germline cells in adult tissues, which is strikingly different from that in mammals. However, whether this expression profile is conservative in fishes remains to be investigated. Here Nile tilapia (Oreochromis niloticus) nanog (named as Ong) was identified and its spatiotemporal expression patterns during embryonic and gonadal development were investigated. The Ong cDNA contains an open reading frame of 678 bp, encoding 226 amino acids. The anti-Ong antibody was prepared through prokaryotic protein expression and its specificity was validated. The Ong expression in embryonic 1-cell stage did not appear until the early stage of blastocyst and continued to the late stage of blastocyst. In adult tissues, its expression was limited to gonads. Its expression patterns during gonadal development were further investigated by in situ hybridization and immunohistochemical staining. In testis, Ong was not expressed at 30 dah (days after hatching), but highly expressed in spermatogonia and spermatocytes at 150 dah; in ovaries at 30 and 150 dah, it was not expressed in germline cells but in all somatic cells. This expression profile is strikingly different from reports in fishes to date. Our study firstly indicates that the Nanog expression profile is not conservative in fishes. This study is valuable for further functional and evolutionary study of this gene.

Transforming growth factor-beta (TGF-β) in prostate cancer: A dual function mediator?

Transforming growth factor-beta (TGF-β) is a member of a family of secreted cytokines with vital biological functions in cells. The abnormal expression of TGF-β signaling is a common finding in pathological conditions, particularly cancer. Prostate cancer (PCa) is one of the leading causes of death among men. Several genetic and epigenetic alterations can result in PCa development, and govern its progression. The present review attempts to shed some light on the role of TGF-β signaling in PCa. TGF-β signaling can either stimulate or inhibit proliferation and viability of PCa cells, depending on the context. The metastasis of PCa cells is increased by TGF-β signaling via induction of EMT and MMPs. Furthermore, TGF-β signaling can induce drug resistance of PCa cells, and can lead to immune evasion via reducing the anti-tumor activity of cytotoxic T cells and stimulating regulatory T cells. Upstream mediators such as microRNAs and lncRNAs, can regulate TGF-β signaling in PCa. Furthermore, some pharmacological compounds such as thymoquinone and valproic acid can suppress TGF-β signaling for PCa therapy. TGF-β over-expression is associated with poor prognosis in PCa patients. Furthermore, TGF-β up-regulation before prostatectomy is associated with recurrence of PCa. Overall, current review discusses role of TGF-β signaling in proliferation, metastasis and therapy response of PCa cells and in order to improve knowledge towards its regulation, upstream mediators of TGF-β such as non-coding RNAs are described. Finally, TGF-β regulation and its clinical application are discussed.

LncRNA PICSAR binds to miR-485-5p and activates TGF-β1/Smad to promote abnormal proliferation of hypertrophic scar fibroblasts (HSFs) and excessive deposition of extracellular matrix (ECM)

The purpose of this study is to explore whether LncRNA PICSAR binds to miR-485-5p and thereby activates TGF-β1/Smad signaling pathway, influencing the abnormal proliferation of fibroblasts and excessive deposition of ECM in hypertrophic scar formation. PICSAR and miR-485-5p expressions were detected by qPCR. Cell proliferation was examined by CCK-8. Protein expressions were determined by western blot. Immunofluorescence detected the Ki-67 expression. Dual-luciferase followed by immunoprecipitation was performed to verify the interaction between PICSAR and miR-485-5p. Interference with PICSAR inhibited the abnormal proliferation of hypertrophic scar fibroblasts (HSFs) and the excessive deposition of ECM. It was also confirmed in our study that MiR-485-5p is a direct target of PICSAR in HSFs. Additionally, inhibition of miR-485-5p reversed the effect of PICSAR knockdown in HSFs. LncRNA PICSAR binds to miR-485-5p and thereby activates TGF-β1/Smad signaling pathway, promoting the abnormal proliferation of fibroblasts and excessive deposition of ECM in hypertrophic scar formation.