Pin1 acts as a modulator of cell proliferation through alteration in NF-κB but not β-catenin/TCF4 signalling in a subset of endometrial carcinoma cells

PIN1P1 is activated by CREB1 and promotes gastric cancer progression via interacting with YBX1 and upregulating PIN1

Long noncoding RNAs (lncRNAs) play critical roles in the carcinogenesis and progression of cancers. However, the role and mechanism of the pseudogene lncRNA PIN1P1 in gastric carcinoma remain unclear. The expression and effects of lncRNA PIN1P1 in gastric cancer were investigated. The transcriptional regulation of CREB1 on PIN1P1 was determined by ChIP and luciferase assays. The mechanistic model of PIN1P1 in gastric cancer was further explored by RNA pull-down, RIP and western blot analysis. PIN1P1 was overexpressed in gastric cancer tissues, and upregulated PIN1P1 predicted poor prognosis in patients. CREB1 was directly combined with the promoter region of PIN1P1 to promote the transcription of PIN1P1. CREB1-mediated enhanced proliferation, migration and invasion could be partially reversed by downregulation of PIN1P1. Overexpressed PIN1P1 promoted the proliferation, migration and invasion of gastric cancer cells, whereas decreased PIN1P1 showed the opposite effects. PIN1P1 directly interacted with YBX1 and promoted YBX1 protein expression, leading to upregulation of PIN1, in which E2F1 may be involved. Silencing of YBX1 during PIN1P1 overexpression could partially rescue PIN1 upregulation. PIN1, the parental gene of PIN1P1, was elevated in gastric cancer tissues, and its upregulation was correlated with poor patient outcomes. PIN1 facilitated gastric cancer cell proliferation, migration and invasion. To sum up, CREB1-activated PIN1P1 could promote gastric cancer progression through YBX1 and upregulating PIN1, suggesting that it is a potential target for gastric cancer.

Targeting prolyl isomerase Pin1 as a promising strategy to overcome resistance to cancer therapies

The development of tumor therapeutic resistance is one of the important reasons for the failure of antitumor therapy. Starting with multiple targets and multiple signaling pathways is helpful in understanding the mechanism of tumor resistance. The overexpression of prolyl isomerase Pin1 is highly correlated with the malignancy of cancer, since Pin1 controls many oncogenes and tumor suppressors, as well as a variety of cancer-driving signaling pathways. Strikingly, numerous studies have shown that Pin1 is directly involved in therapeutic resistance. In this review, we mainly summarize the functions and mechanisms of Pin1 in therapeutic resistance of multifarious cancers, such as breast, liver, and pancreatic carcinomas. Furtherly, from the perspective of Pin1-driven cancer signaling pathways including Raf/MEK/ERK, PI3K/Akt, Wnt/β-catenin, NF-κB, as well as Pin1 inhibitors containing juglone, epigallocatechin-3-gallate (EGCG), all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), it is better to demonstrate the important potential role and mechanism of Pin1 in resistance and sensitization to cancer therapies. It will provide new therapeutic approaches for clinical reversal and prevention of tumor resistance by employing synergistic administration of Pin1 inhibitors and chemotherapeutics, implementing combination therapy of Pin1-related cancer signaling pathway inhibitors and Pin1 inhibitors, and exploiting novel Pin1-specific inhibitors.

Targeting Pin1 for Modulation of Cell Motility and Cancer Therapy

Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) specifically binds and isomerizes the phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif, which leads to changes in protein conformation and function. Pin1 is widely overexpressed in cancers and plays an important role in tumorigenesis. Mounting evidence has revealed that targeting Pin1 is a potential therapeutic approach for various cancers by inhibiting cell proliferation, reducing metastasis, and maintaining genome stability. In this review, we summarize the underlying mechanisms of Pin1-mediated upregulation of oncogenes and downregulation of tumor suppressors in cancer development. Furthermore, we also discuss the multiple roles of Pin1 in cancer hallmarks and examine Pin1 as a desirable pharmaceutical target for cancer therapy. We also summarize the recent progress of Pin1-targeted small-molecule compounds for anticancer activity.

Isoquinolinequinone Derivatives from a Marine Sponge (Haliclona sp.) Regulate Inflammation in In Vitro System of Intestine

Using bio-guided fractionation and based on the inhibitory activities of nitric oxide (NO) and prostaglandin E2 (PGE2), eight isoquinolinequinone derivatives (1–8) were isolated from the marine sponge Haliclona sp. Among these, methyl O-demethylrenierate (1) is a noble ester, whereas compounds 2 and 3 are new O-demethyl derivatives of known isoquinolinequinones. Compound 8 was assigned as a new 21-dehydroxyrenieramycin F. Anti-inflammatory activities of the isolated compounds were tested in a co-culture system of human epithelial Caco-2 and THP-1 macrophages. The isolated derivatives showed variable activities. O-demethyl renierone (5) showed the highest activity, while 3 and 7 showed moderate activities. These bioactive isoquinolinequinones inhibited lipopolysaccharide and interferon gamma-induced production of NO and PGE2. Expression of inducible nitric oxide synthase, cyclooxygenase-2, and the phosphorylation of MAPKs were down-regulated in response to the inhibition of NF-κB nuclear translocation. In addition, nuclear translocation was markedly promoted with a subsequent increase in the expression of HO-1. Structure-activity relationship studies showed that the hydroxyl group in 3 and 5, and the N-formyl group in 7 may be key functional groups responsible for their anti-inflammatory activities. These findings suggest the potential use of Haliclona sp. and its metabolites as pharmaceuticals treating inflammation-related diseases including inflammatory bowel disease.

Pin1 promotes pancreatic cancer progression and metastasis by activation of NF-κB-IL-18 feedback loop

Objectives

Accumulated evidence suggests that Pin1 contributes to oncogenesis of diverse cancers. However, the underlying mechanism of oncogenic function of Pin1 in PDAC requires further exploration.

Materials and Methods

IHC was performed using PDAC tissues. Western blot, PCR, immunofluorescence and transwell were performed using cell lines. GSEA were applied for possible downstream pathways. ChIP assay and dual luciferase were used for assessment of transcriptional activity.

Results

Both Pin1 and IL‐18 levels are increased in primary PDAC tissues and that their levels are positively correlated. High expression of IL‐18 is a predictor of poor prognoses. Pin1 promoted pancreatic cancer cell proliferation and motility by increasing IL‐18 expression, while Pin1 knockdown also inhibited the tumour‐promoting effect of IL‐18. Both Pin1 and IL‐18 could enhance the NFκB activity in pancreatic cancer cells. When bound to the p65 protein, Pin1 promoted p65 phosphorylation and its nuclear translocation. In the nucleus, Pin1 and p65 simultaneously bound to the IL‐18 promoter and enhanced IL‐18 transcription. In addition, recruitment of p65 to the IL‐18 promoter was decreased in Pin1‐silenced cells.

Conclusions

Our study improves the understanding of Pin1 in tumour‐promoting inflammation in PDAC, which is a hallmark of cancer; Pin1 interacted with p65 in PDAC and enhanced NF‐κB signalling and downstream transcriptional activation of IL‐18, with increased IL‐18 continuously activating NF‐κB signalling, which then forms a positive feedback loop.

Prolyl Isomerase Pin1 in Human Cancer: Function, Mechanism, and Significance

Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) is an evolutionally conserved and unique enzyme that specifically catalyzes the cis-trans isomerization of phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif and, subsequently, induces the conformational change of its substrates. Mounting evidence has demonstrated that Pin1 is widely overexpressed and/or overactivated in cancer, exerting a critical influence on tumor initiation and progression via regulation of the biological activity, protein degradation, or nucleus-cytoplasmic distribution of its substrates. Moreover, Pin1 participates in the cancer hallmarks through activating some oncogenes and growth enhancers, or inactivating some tumor suppressors and growth inhibitors, suggesting that Pin1 could be an attractive target for cancer therapy. In this review, we summarize the findings on the dysregulation, mechanisms, and biological functions of Pin1 in cancer cells, and also discuss the significance and potential applications of Pin1 dysregulation in human cancer.

Function of PIN1 in Cancer Development and Its Inhibitors as Cancer Therapeutics

Peptidyl-prolyl isomerase (PIN1) specifically binds and isomerizes the phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif, which results in the alteration of protein structure, function, and stability. The altered structure and function of these phosphorylated proteins regulated by PIN1 are closely related to cancer development. PIN1 is highly expressed in human cancers and promotes cancer as well as cancer stem cells by breaking the balance of oncogenes and tumor suppressors. In this review, we discuss the roles of PIN1 in cancer and PIN1-targeted small-molecule compounds.

Deacetylphylloketal, a New Phylloketal Derivative from a Marine Sponge, Genus Phyllospongia, with Potent Anti-Inflammatory Activity in In Vitro Co-Culture Model of Intestine

The inflammatory bowel diseases (IBD) cause chronic inflammation of the gastrointestinal tract and include ulcerative colitis (UC) and Crohn’s disease (CD). The prevalence of IBD has been increasing worldwide, and has sometimes led to irreversible impairment of gastrointestinal structure and function. In the present study, we successfully isolated a new phylloketal derivative, deacetylphylloketal (1) along with four known compounds from the sponge genus Phyllospongia. The anti-inflammatory properties of deacetylphylloketal (1) and phyllohemiketal A (2) were evaluated using an in vitro co-culture system that resembles the intestinal epithelial environment. A co-culture system was established that consisted of human epithelial Caco-2 cells and phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 macrophage cells. The treatment of co-cultured THP-1 cells with compounds 1 or 2 significantly suppressed the production and/or gene expression of lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2), Interleukin-6 (IL-6), IL-1β and Tumor Necrosis Factor alpha (TNF-α). The expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 were down-regulated in response to inhibition of NF-kB translocation into the nucleus in cells. In addition, we observed that 1 and 2 markedly promoted the nuclear translocation of Nrf2 and subsequent increase in the expression of heme oxygernase (HO)-1. These findings suggest the potential use of sponge genus Phyllospongia and its metabolites as a pharmaceutical aid in the treatment of inflammation-related diseases including IBD.

(10Z)-Debromohymenialdisine from Marine Sponge Stylissa sp. Regulates Intestinal Inflammatory Responses in Co-Culture Model of Epithelial Caco-2 Cells and THP-1 Macrophage Cells

Crohn’s disease (CD) and ulcerative colitis (UC), collectively referred to as inflammatory bowel disease (IBD), are autoimmune diseases characterized by chronic inflammation within the gastrointestinal tract. Debromohymenialdisine is an active pyrrole alkaloid that is well known to serve as a stable and effective inhibitor of Chk2. In the present study, we attempted to investigate the anti-inflammatory properties of (10Z)-debromohymenialdisine (1) isolated from marine sponge Stylissa species using an intestinal in vitro model with a transwell co-culture system. The treatment with 1 attenuated the production and gene expression of lipopolysaccharide (LPS)-induced Interleukin (IL)-6, IL-1β, prostaglandin E2 (PGE2), and tumor necrosis factor-α in co-cultured THP-1 macrophages at a concentration range of 1–5 μM. The protein expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 were down-regulated in response to the inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation into the nucleus in cells. In addition, we observed that 1 markedly promoted the nuclear translocation of nuclear factor erythroid 2 related factor 2 (Nrf2) and subsequent increase of heme oxygenase-1 (HO-1) expression. These findings suggest the potential use of 1 as a pharmaceutical lead in the treatment of inflammation-related diseases including IBD.

Prolyl isomerase Pin1: a promoter of cancer and a target for therapy

Pin1 is the only known peptidyl-prolyl cis–trans isomerase (PPIase) that specifically recognizes and isomerizes the phosphorylated Serine/Threonine-Proline (pSer/Thr-Pro) motif. The Pin1-mediated structural transformation posttranslationally regulates the biofunctions of multiple proteins. Pin1 is involved in many cellular processes, the aberrance of which lead to both degenerative and neoplastic diseases. Pin1 is highly expressed in the majority of cancers and its deficiency significantly suppresses cancer progression. According to the ground-breaking summaries by Hanahan D and Weinberg RA, the hallmarks of cancer comprise ten biological capabilities. Multiple researches illuminated that Pin1 contributes to these aberrant behaviors of cancer via promoting various cancer-driving pathways. This review summarized the detailed mechanisms of Pin1 in different cancer capabilities and certain Pin1-targeted small-molecule compounds that exhibit anticancer activities, expecting to facilitate anticancer therapies by targeting Pin1.

Artemisinin triggers a G1 cell cycle arrest of human Ishikawa endometrial cancer cells and inhibits cyclin-dependent kinase-4 promoter activity and expression by disrupting nuclear factor-κB transcriptional signaling

Relatively little is known about the antiproliferative effects of artemisinin, a naturally occurring antimalarial compound from Artemisia annua, or sweet wormwood, in human endometrial cancer cells. Artemisinin induced a G1 cell cycle arrest in cultured human Ishikawa endometrial cancer cells and downregulated cyclin-dependent kinase-2 (CDK2) and CDK4 transcript and protein levels. Analysis of CDK4 promoter-luciferase reporter constructs showed that the artemisinin ablation of CDK4 gene expression was accounted for by the loss of CDK4 promoter activity. Chromatin immunoprecipitation demonstrated that artemisinin inhibited nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) subunit p65 and p50 interactions with the endogenous Ishikawa cell CDK4 promoter. Coimmunoprecipitation revealed that artemisinin disrupts endogenous p65 and p50 nuclear translocation through increased protein-protein interactions with IκB-α, an NF-κB inhibitor, and disrupts its interaction with the CDK4 promoter, leading to a loss of CDK4 gene expression. Artemisinin treatment stimulated the cellular levels of IκB-α protein without altering the level of IκB-α transcripts. Finally, expression of exogenous p65 resulted in the accumulation of this NF-κB subunit in the nucleus of artemisinin-treated and artemisinin-untreated cells, reversed the artemisinin downregulation of CDK4 protein expression and promoter activity, and prevented the artemisinin-induced G1 cell cycle arrest. Taken together, our results demonstrate that a key event in the artemisinin antiproliferative effects in endometrial cancer cells is the transcriptional downregulation of CDK4 expression by disruption of NF-κB interactions with the CDK4 promoter.

Pin1-Nanog expression in human glioma is correlated with advanced tumor progression

The stemness gene Nanog has been shown to play an important role in tumor development, including glioma. Nanog is phosphorylated at multiple Ser/Thr-Pro motifs, which promotes the interaction between Nanog and the prolyl isomerase Pin1, leading to Nanog stabilization by suppressing its ubiquitination. The present study investigated the expression and relationship of Pin1 and Nanog in human gliomas. Significantly higher mRNA and protein expression levels of Pin1 and Nanog were demonstrated in 120 glioma specimens of different pathological grades by RT-PCR, immunohistochemistry staining and western blot analysis. The relative levels of Pin1 expression, as well as Nanog expression, were significantly positively correlated with pathological grade. Moreover, a positive correlation of Pin1 and Nanog expression in human gliomas was noted. Co-localization of Pin1 and Nanog was observed in the perinuclear space in the cytoplasm of glioma cells detected by immunofluorescence staining. Significantly positive correlation between Pin1 and Nanog in gliomas indicated that Pin1 and Nanog may be related to tumorigenesis and development of glioma cells.

Dissecting Pin1 and phospho-pRb regulation

The activity of the Retinoblastoma protein, the master regulator of the cell cycle, is finely regulated by phosphorylation. CDKs and cyclins are major players in phosphorylation and it has been recently discovered that the prolyl isomerase Pin1 is an essential protein that orchestrates this process. In this article, we report new findings regarding the role of Pin1 in the pRb pathway. Our data suggest that PI3K, CDKs, and the Pin1 axis have a critical role in sustaining the complete phosphorylation of pRb. Furthermore, we analyze the correlation between Pin1 and pRb phosphorylation in vivo. We show that, in human malignant glioma tissue microarrays (TMA) and in Pin1 knockout (KO) mice, there is a positive correlation between Pin1 and pRb phosphorylation. Prospectively, our findings suggest that the synergism between CDKs, Pin1, and PI3K inhibitors hold great promise for targeted pharmacological treatment of cancer patients, with the possibility of reaching high effectiveness at tolerated doses.

Transcriptional up-regulation of Sox9 by NF-κB in endometrial carcinoma cells, modulating cell proliferation through alteration in the p14(ARF)/p53/p21(WAF1) pathway

The Sox factors are a large family of transcription factors that play important roles in tumor development and progression in a variety of human malignancies and diverse developmental processes, but little is known about their roles in endometrial tumorigenesis. Herein, we focus on the functions of Sox9 in endometrial carcinomas. Cells stably overexpressing Sox9 showed a low proliferation rate, particularity in the exponential growth phase, along with increased amounts of p21(WAF1). Transient transfection of Sox9 caused transactivation of p21(WAF1) and p14(ARF) promoters, in cooperation with p53, resulting in activation of the p14(ARF)/p53/p21(WAF1) pathway. Overexpression of p65, and the constitutively active form myristylated Akt, led to an increase in Sox9 expression through transcriptional and posttranslational mechanisms. In normal endometrium, biphasic up-regulation of Sox9 expression was observed during the menstrual cycle, labeling indices being significantly higher in the proliferative stage than in the secretory stage. Moreover, expression also showed a significant stepwise increase from normal through grade 1 to grade 2/3 tumors, being correlated positively with labeling indices of p53, p21(WAF1), pp65, and Ki-67, probably due to a feedback system regarding cell proliferation through NF-κB and Akt signaling. These data, therefore, suggest that associations between Sox9 and NF-κB signaling, as well as Akt status, may participate in modulation of the cell kinetics of endometrial carcinomas cells through alteration in the p14(ARF)/p53/p21(WAF1) pathway.

Sox4 functions as a positive regulator of β-catenin signaling through upregulation of TCF4 during morular differentiation of endometrial carcinomas

Sox factors function as either activators or repressors of β-catenin/TCF transcription depending on the cellular context and associated interacting proteins. Our previous study provided evidence that alteration in β-catenin signaling is an essential event during transdifferentiation toward the morular phenotype of endometrial carcinomas (Em Cas). Here, we focused on related functional roles of Sox factors. Of eight Sox factors investigated, Sox4 could enhance β-catenin/TCF4 transcription, through upregulation of TCF4 at the transcription level, without any direct β-catenin association. Cells stably overexpressing Sox4 showed significant decreases in proliferation rate, along with increases in expression of p21(WAF1), as well as TCF4, in contrast to increased cell growth observed with knockdown. Of these factors, only Sox7 could transcriptionally upregulate Sox4 expression, but it also resulted in not only inhibition of Sox4-meditated activation of β-catenin/TCF4-driven transcription, but also repression of its own promoter activity, indicating the existence of very complex feedback loop for Sox-mediated signal cascades. Finally, Sox4 immunoreactivity was frequently pronounced in morular lesions of Em Cas, the expression being positively correlated with status of β-catenin, TCF4, and Sox7, and inversely with cell proliferation. These data therefore suggest that Sox4 may serve as a positive regulator of β-catenin signaling through alteration in TCF4 expression during morular differentiation of Em Ca cells, leading to inhibition of cell proliferation. In addition, Sox7 may also participate in the process, having complex roles in modulation of signaling.