Kip1 Expression Research Articles

Baicalin suppress the development of polycystic ovary syndrome via regulating the miR-874-3p/FOXO3 and miR-144/FOXO1 axis

Context Polycystic ovary syndrome (PCOS) is a common and complex disease caused by endocrine and metabolic dysfunction in women of reproductive age. Baicalin is reported to ameliorate PCOS. Objective This study determines whether baicalin could affect the progression of PCOS. Materials and methods To establish an animal model of PCOS, female Sprague-Dawley (SD) rats were subcutaneously injected with dehydroepiandrosterone (DHEA, 60 mg/kg) for 20 days. Next, normal and PCOS mice were divided into 3 groups: control, PCOS, PCOS + Baicalin (20 mg/kg) groups. In addition, the levels of microRNA-874-3p (miR-874-3p) and microRNA-144 (miR-144) in ovarian tissues were assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Results Compared to the PCOS group, baicalin treatment significantly declined free testosterone (33.71 pg/mL vs. 56.05 pg/mL) and luteinizing hormone (LH; 3971.73 pg/mL vs. 5201.50 pg/mL) levels in rats with PCOS. Additionally, compared to the control group, 100 μM baicalin lessened miR-874-3p and miR-144 levels in human ovarian granulosa cells (KGN cells) by 36.87% and 32.57%, respectively. Furthermore, forkhead box O (FOXO) proteins FOXO1 and FOXO3 are the direct targets of miR-144 and miR-874-3p, respectively. Meanwhile, baicalin induced G0-G1 phase arrest (69.56 ± 3.7% at baicalin with 100 μM vs. 51.24 ± 3.2%, control) in KGN cells correlating with decreased p27 Kip1 (FOXO proteins downstream effector gene) expression by 55.5%; however, miR-874-3p or miR-144 overexpression could abolish this effect. Conclusions Baicalin could alleviate the symptoms of PCOS via regulating miR-874-3p/FOXO3 and miR-144/FOXO1 axis, demonstrating its potential utility in PCOS treatment.

Abstract 1544: The lncRNA SNHG1 modulates quiescence and chemoresistance of prostate cancer

Abstract Prostate cancer dormancy and chemoresistance contributes to long term morbidity and mortality from this disease. The long non-coding RNA (lncRNA) SNHG1 is highly expressed in prostate cancer and is associated with poor progression-free survival. We investigated SNHG1 involvement in cell cycle regulation, quiescence, and chemoresistance. Suppression of SNHG1 expression using RNAi in PC3 and C4-2B prostate cancer cells resulted in a cessation of proliferation. SNHG1-deficient cells maintained viability, but did not increase in numbers over 7 days post-siRNA transfection. Control cells (siCTRL), meanwhile, expanded 12 and 10-fold, respectively. Analysis of DNA synthesis by EdU staining PC3 cells showed 32% EdU+ siCTRL, but only 7.0% EdU+ siSNHG1, cells. Likewise, C4-2B cells had reduced EdU staining after SNHG1 RNAi. We then analyzed cell cycle and apoptosis in C4-2B, Du145, and LNCaP cells by propidium iodide (PI) staining. Following SNHG1 RNAi, no significant increase in apoptosis or cell cycle arrest was observed, compared to controls. The reduction in S-phase cells was analogous to EdU staining, and there was a modest decrease in G2 phase cells. To investigate quiescence, we knocked down SNHG1 in PC3 cells engineered to express the fluorescent markers Venus and mCherry concurrently with expression of CDT1 and p27, as a marker of G0-phase cells. In SNHG1-deficient cells, 48% were in G0 phase (Venus+, mCherry+), while 13% of siCTRL cells were in G0 phase, indicating that loss of SNHG1 expression blocked cells from exiting G0 and entering the cell cycle. In C4-2B, knockdown of SNHG1 resulted in a 4-5-fold increase in p27(Kip1) expression by immunoblot, indicating increased numbers of quiescent cells. We assessed induction of apoptosis following docetaxel treatment in SNHG1-deficient cells. We found that 20 nM docetaxel induced a 2.9 and 11-fold increase in PARP cleavage in siCTRL-transfected PC3 and C4-2B cells compared to untreated, respectively. When SNHG1 was suppressed by RNAi, PARP cleavage following docetaxel treatment changed by 0.58 and 3.6-fold in PC3 and C4-2B cells, respectively. In addition, we found caspase 3 cleavage after docetaxel treatment was reduced following SNHG1 knockdown, compared to controls. These data indicate cells deficient in SNHG1 are more resistant to docetaxel. Because docetaxel also induced a G2 arrest, we quantified G2 phase by PI staining for DNA content, and immunoblotting for cyclin B1, a marker of G2/M, in siCTRL and siSNHG1 cells. There was a complete elimination of the docetaxel-induced G2 arrest in cells deficient in SNHG1. These data show that SNHG1 plays a role in prostate cancer cell cycle, which has an impact on response to chemotherapy. SNHG1-deficient cells accumulated in G0 phase, and there was reduced apoptosis and resistance to G2 arrest following docetaxel treatment. This is consistent with a model whereby low SNHG1 expression maintains dormancy and protects cells from treatment. Citation Format: Steven P. Zielske, Frank C. Cackowski. The lncRNA SNHG1 modulates quiescence and chemoresistance of prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1544.

LncRNA HCG11 suppresses human osteosarcoma growth through upregulating p27 Kip1.

Osteosarcoma (OS) is a common malignant bone cancer threatening children and young adults. Emerging evidence indicates that long non-coding RNAs (lncRNAs) play crucial roles in the progression of OS. Herein, we want to clarify the roles of lncRNA human leukocyte antigen complex group 11 (HCG11) in OS. Our data revealed that HCG11 expression is decreased in OS, which is a result of transcriptional repression of YY1. Low HCG11 level is closely associated with larger tumor size and shorter overall survival of OS patients. HCG11 negatively regulates cell proliferation, cell cycle, DNA replication in vitro and tumor growth in vivo. HCG11 can raise p27 Kip1 expression via binding to miR-942-5p and IGF2BP2, and p27 Kip1 acts as a key effector for HCG11 exerting biological functions. In conclusion, HCG11 is downregulated in OS, and restrains OS growth both in vitro and in vivo by raising p27 Kip1 expression via binding to miR-942-5p and IGF2BP2.

Deficiency of heat shock factor 4 promotes lens epithelial cell senescence through upregulating p21cip1 expression

Genetic mutations in heat shock factor 4 (Hsf4) is associated with both congenital and age-related cataracts. Hsf4 regulates lens development through its ability to both activate and inhibit transcription. Previous studies suggested Hsf4 is involved in modulating cellular senescence depending on p21cip1 and p27 kip1 expression in MEF cells. Here, we found that Hsf4 acts as a suppressor of p21cip1 expression and plays an anti-senescence role during lens development. Knocking out Hsf4 facilitated UVB-induced cellular senescence in mouse lens epithelial cells (mLECs). p21cip1 was upregulated at both the mRNA and protein levels in HSF4−/− mLECs under control and UVB-treated conditions, and knockdown of p21cip1 by siRNA alleviated UVB-induced cellular senescence. HSF4 directly bound to the p21cip1 promoter and increased H3K27m3 levels at the p21cip1 proximal promoter region by recruiting the methyltransferase EZH2. In animal models, p21cip1 was gradually upregulated in wild-type mouse lenses with increasing age, while Hsf4 levels decreased. We generated a Hsf4 mutant mice line (Hsf4del-42) which displayed obvious congenital cataract phenotype. The expression of p21cip1 and senescence-associated cytokines were induced in the cataractous lenses of Hsf4del-42 mice. H3K27m3 and EZH2 levels decreased in p21cip1 promoters in the lenses of Hsf4del-42 mice. The SA-β-Gal activities were positive in lens epithelia of aged Hsf4null zebrafish compared to wild-type lenses. p21cip1 and senescence-associated cytokines levels were also upregulated in lenses of Hsf4null zebrafish. Accordingly, we propose that HSF4 plays a protective role in lens epithelial cells against cellular senescence during lens development and aging, partly by fine-tuning p21cip1 expression.

Clinical significance of p27 Kip1 expression in advanced ovarian cancer

BackgroundOvarian cancer is the most common gynecological malignancy. In patients with advanced ovarian cancer, some biological parameters have prognostic implementations. P27kip1 is an inhibitor of a cycline-dependent kinase, its loss, can contribute to tumor progression.ObjectiveThis study aimed to examine the importance of P27KIP1 protein in predicting the prognosis and response to neoadjuvant chemotherapy in patients with advanced ovarian epithelial cancer and to compare the outcomes of immunohistochemistry with Quantitative Real-time PCR.Patients and methodsWe have studied P27KIP1expression by both immunohistochemistry and Quantitative Real-time PCR from 88 patients with advanced ovarian carcinomas undergone radical debulking surgery and received Paclitaxel followed by Cisplatin every 3 weeks for a total of 6 cycles. We also studied their association with both chemotherapy response and patient survival.ResultsNuclear expression of p27KIP1 protein was intense in 86 normal ovarian tissues and 42 of 88 carcinomas. The P27kip1mRNA expression level by qRT-PCR was very low in ovarian cancer tissues relative to its adjacent normal tissues. The results were statistically significant by both methods of determination. p27KIP1 expression was significantly related to good prognostic parameters as low stage tumors, differentiated tumors, absence of ascites, residual disease < 2 cm, and response to chemotherapy but not with histopathological type in case of determination by immunohistochemistry. Comparison of P27kip1 by both immunohistochemistry and qRT-PCR with different prognostic parameters revealed no significant difference between both methods in the assessment of these parameters. In 4 years of follow-up, 20.5% of patients were alive without evidence of disease. 6.8% were alive with disease. The disease-related four -year survival rate for the whole group was 28.2%. In multivariate analysis, residual disease, histological type, tumor differentiation, ascites was of independent prognostic significance.ConclusionIn ovarian cancer, patients with loss of p27KIP1 expression are at a greater likelihood of disease progression, p27KIP1 may be used as a molecular marker to predict response to chemotherapy and prognosis. Both immunohistochemistry and qRT-PCR have equal reliability in the determination of p27 KIP1.

Circular RNA YAP1 inhibits the proliferation and invasion of gastric cancer cells by regulating the miR-367-5p/p27 Kip1 axis

BackgroundCircular RNAs (circRNAs) are a new type of non-coding RNAs and their functions in gastric cancer (GC) remain unclear. Recent studies have revealed that circRNAs play an important role in cancer development and certain types of pathological responses, acting as microRNA (miRNA) sponges to regulate gene expression.MethodsCircNet was used to screen potential circRNAs and validated circYAP1 expression levels in 17 GC tissues by quantitative real-time PCR (qRT-PCR) and another 80 paired GC tissues by FISH. CircYAP1 overexpression and knockdown experiments were conducted to assess the effects of circYAP1 in vitro and in vivo, and its molecular mechanism was demonstrated by RNA in vivo precipitation assays, western blotting, luciferase assay and rescue experiments.ResultsCircYAP1 expression level was significantly lower in GC tissues than the adjacent normal tissues, and GC patients with circYAP1 low expression had shorter survival times as compared with those with circYAP1 high expression. Functionally, circYAP1 overexpression inhibited cell growth and invasion in vitro and in vivo, but its knockdown reversed these effects. Further analysis showed that circYAP1 sponged miR-367-5p to inhibit p27 Kip1 expression and GC progression.ConclusionOur findings demonstrate that circYAP1 functions as a tumor suppressor in GC cells by targeting the miR-367-5p/p27 Kip1 axis and may provide a prognostic indicator of survival in GC patients.

S100A7, Jab1, and p27kip1 expression in psoriasis and S100A7 CRISPR-activated human keratinocyte cell line.

Psoriasis, a chronic immune-mediated inflammatory skin disease, is characterized by dysregulated keratinocyte proliferation. The EF-hand calcium binding protein S100A7 has been found to be overexpressed in psoriatic keratinocytes. It is know that S100A7 may interact with Jab1, a cofactor that stabilizes c-Jun. Jab1 is known to downregulate the expression of the cell cycle inhibitor p27Kip1 in some cancer models. In this study, we aimed to investigate the possible interaction between S100A7 and Jab1 and the downstream effects on p27 Kip1 expression in normal human keratinocyte cells transfected with S100A7 CRISPR activation plasmid and in archival psoriatic skin samples. Our results showed that the upregulated S100A7 colocalizes with Jab1 at the nuclear level in transfected cells and psoriatic skin samples. We also showed a differential protein expression of Jab1 between cytoplasmic and nuclear compartments, thus suggesting Jab1 translocation from nucleus to cytoplasm. p27 Kip1 protein expression patterns would imply a translocation from nucleus and a subsequent degradation of this protein. The upregulation of S1007 and its interaction with Jab1 would contribute to the p27 Kip1 -dependent impaired proliferation that characterizes psoriatic skin.

1α,25-dihydroxyvitamin D3 inhibits Aflatoxin B1-Induced proliferation and malignant transformation of hepatic progenitor cells by regulating PI3K/Akt and hippo pathways

Background: Hepatic progenitor cells (HPCs) might be the origin of hepatocellular carcinoma. 1α, 25-dihydroxyvitamin D3 (1, 25(OH)2D3) is capable of inhibiting the proliferation of various cancer cells . This study was conducted to determine the potential of 1α, 25(OH)2D3 to inhibit proliferation and malignant transformation of HPCs induced by aflatoxin B1 (AFB1) and explore the mechanism of inhibition. Methods: A rat HPC cell line, WB F-344 cells, were treated with AFB1, 1α, 25(OH)2D3 or combination. Cell proliferation, apoptosis, cell cycle, differentiation and invasion were measured. ICR mice were exposed to AFB1 every day for 14 d, the liver function and immunohistochemistry were surveyed. Results: AFB1 exhibited the stimulative effects on the proliferation, dedifferentiation and invasion of HPCs. In this period, the phosphorylation of AKT, expression of Yap, Taz, cyr61 and cyclin D1 were increased in cells. At the same time, phosphorylation of lats1, expression of p21 Kip1 were reduced in AFB1-treated cells. When F-344 cells were treated with AFB1 in combination with 1α, 25(OH)2D3, it was found that 1α, 25(OH)2D3 inhibited these effects of AFB1 on HPCs. Meanwhile, the expression and phosphorylation of the above pathways were reversed compared to treatment with AFB1 alone. Conclusions: These results suggest that AFB1 could induce proliferation, differentiation and transformation of HPCs, and that an enhanced 1α, 25(OH)2D3 negatively regulates the inductive effects of AFB1 on HPCs by suppressing the activation of Akt, activating Hippo pathways.

Expression of protein p27 in various forms of seborrheic keratosis

The significant role in the pathogenesis of seborrheic keratosis (SK) plays the violation of the cell cycle regulation. According to the research unit the cell proliferation in acanthotic and irritated histological types of SK is regulated by p27 (Kip1), cyclin-dependent kinase inhibitor. Considering the variety of histological types of SK, definition of p27 expression will reveal the characteristic features of the cell cycle disorders and proliferation for each type of tumor. Material and Methods. Of the 102 tumors from patients with SK, according to the results of histological examination, were selected 10 specimens of each histological types of SK: acanthotic, hyperkeratotic, adenoid, irritated, and clonal. We assessed all specimens for p27 (Kip1) expression using immunohistochemistry (monoclonal antibody p27 at a dilution of 1:20 (Novocastra Laboratories Ltd.). Three skin biopsy samples of healthy individuals were included. Results. Severe diffuse nuclear expression of p27 was present in all cases of adenoid, irritated, and 4 cases of clonal histological types of SK. In other tumor types positive reaction with monoclonal antibody to p27 was reduced as compared with healthy skin were recorded single positively stained nuclei of basal cells. Conclusions. Thus, we have found a violation of p27 protein expression in all types of seborrheic keratosis as with the excess (adenoid, irritated, clonal SK type) and in p27 protein deficiency (acanthotic, hyperkeratotic) normal course of cell cycle phases is broken. This leads to the disappearance of control over the cell proliferative activity and apoptosis, facilitating a slow, uncontrolled growth of SK cells.

Herbal composition of Cinnamomum cassia, Pinus densiflora, Curcuma longa and Glycyrrhiza glabra prevents atherosclerosis by upregulating p27 (Kip1) expression

BackgroundKiom-18 is a novel composition of Cinnamomum cassia, Pinus densiflora, Curcuma longa and Glycyrrhiza glabra. Curcuma longa and Glycyrrhiza glabra, which are traditional medicines in Asia, have been reported to demonstrate preventive effects against atherosclerosis; however, they have not yet been developed into functional atherosclerosis treatments. We therefore studied the anti-atherosclerotic effects and possible molecular mechanisms of Kiom-18 using vascular smooth muscle cells (VSMCs).MethodsTo assess the anti-proliferative effect of Kiom-18 in vitro, we performed thymidine incorporation, cell cycle progression, immunoblotting and immunofluorescence assays in VSMCs stimulated by platelet derived-growth factor (PDGF)-BB. In addition, we used LDLr knockout mice to identify the effects of Kiom-18 as a preliminary result in an atherosclerosis animal model.ResultsKiom-18 inhibited platelet-derived growth factor (PDGF)-BB-stimulated-VSMC proliferation and DNA synthesis. Additionally, Kiom-18 arrested the cell cycle transition of G0/G1 stimulated by PDGF-BB and its cell cycle-related proteins. Correspondingly, the level of p27kip1 expression was upregulated in the presence of the Kiom-18 extract. Moreover, in an atherosclerosis animal model of LDLr knockout mice, Kiom-18 extract showed a preventive effect for the formation of atherosclerotic plaque and suppressed body weight, fat weight, food treatment efficiency, neutrophil count, and triglyceride level.ConclusionsThese results indicate that Kiom-18 exerts anti-atherosclerotic effects by inhibiting VSMC proliferation via G0/G1 arrest, which upregulates p27Kip1 expression.

The Cables1 Gene in Glucocorticoid Regulation of Pituitary Corticotrope Growth and Cushing Disease.

Cushing disease (CD) is due to pituitary corticotrope adenomas that produce unrestrained ACTH secretion and have lost the negative feedback exerted by glucocorticoids (GCs). GCs also restrain corticotrope proliferation, and the mechanisms of this inhibition are poorly understood. The aim of the study was to identify cell cycle regulatory genes that are regulated by GCs and the glucocorticoid receptor and to assess regulatory genes that have a rate-limiting action on corticotrope proliferation and may be disregulated in CD. The mouse corticotrope tumor cells AtT-20 were used to identify GC-regulated genes that contribute to control of cell cycle progression. Surgery sections from patients with CD were used to assess expression of CABLES1 in corticotrope adenomas. Gene expression profiling, small interfering RNA knockdowns, cell cycle analyses, and genetic manipulations were performed in AtT-20 cells. Sequencing of chromatin immunoprecipitation for pituitary-restricted transcription factors and RNA polymerase II were used to identify regulatory elements and genes that bind GR and are direct transcriptional targets. A panel of previously well-characterized corticotrope adenomas was used to correlate expression of CABLES1 with that of other markers. GCs altered expression of 3 positive and 3 negative regulators of cell cycle progression. Two Myc genes (L-Myc and N-Myc) and E2F2 are repressed by GCs, whereas genes for the negative regulators of the cell cycle, Gadd45β, Gadd45γ, and Cables1 are activated by GCs. Cables1 small interfering RNA knockdown strongly stimulates AtT-20 cell proliferation and antagonizes the growth inhibition produced by GCs. The Gadd45 and Cables1 genes have the hallmarks of direct GC targets. CABLES1 is expressed in normal human pituitary cells, but expression is lost in ∼55% of corticotrope adenomas, and this is strongly correlated with the loss of p27(Kip1) expression. CABLES1 is a critical regulator of corticotrope proliferation that defines a pathway often inactivated in CD and links proliferation to GC resistance.

Fad24, a Positive Regulator of Adipogenesis, Is Required for S Phase Re-entry of C2C12 Myoblasts Arrested in G0 Phase and Involved in p27(Kip1) Expression at the Protein Level.

Factor for adipocyte differentiation 24 (fad24) is a positive regulator of adipogenesis. We previously found that human fad24 is abundantly expressed in skeletal muscle. However, the function of fad24 in skeletal muscle remains largely unknown. Because skeletal muscle is a highly regenerative tissue, we focused on the function of fad24 in skeletal muscle regeneration. In this paper, we investigated the role of fad24 in the cell cycle re-entry of quiescent C2C12 myoblasts-mimicked satellite cells. The expression levels of fad24 and histone acetyltransferase binding to ORC1 (hbo1), a FAD24-interacting factor, were elevated at the early phase of the regeneration process in response to cardiotoxin-induced muscle injury. The knockdown of fad24 inhibited the proliferation of quiescent myoblasts, whereas fad24 knockdown did not affect differentiation. S phase entry following serum activation is abrogated by fad24 knockdown in quiescent cells. Furthermore, fad24 knockdown cells show a marked accumulation of p27(Kip1) protein. These results suggest that fad24 may have an important role in the S phase re-entry of quiescent C2C12 cells through the regulation of p27(Kip1) at the protein level.

Effects of Rapamycin and Rapamycin-loaded Poly(lactic-co-glycolic)Acid Nanoparticles on Apoptosis and Expression of bcl-2 and p27(kip1) Proteins of Human Umbilical Arterial Vascular Smooth Muscle Cell

To investgate the effects of rapamycin(RPM)and RPM-loaded poly(lactic-co-glycolic)acid(PLGA)nanoparticles(NPs)on the apoptosis of human umbilical arterial vascular smooth muscle cells(HUASMCs)in vitro and expression of bcl-2 and p27(kip1) protein. HUASMCs were cultured in vitro and divided to RPM and RPM-PLGA-NPs groups treated at 3 different concentration by 12 and 24 hours,with M231-smooth muscle growth supplements medium and null-PLGA-NPs treated groups as controlled. The apoptosis of HUASMCs was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining and flow cytometry. The expressions of bcl-2 and p27(kip1) were detected by streptacidin/peroxidase immunohistochemical method. The effect on cellular proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidecolorimetry. The proliferation of HUASMCs was inhibited by RPM and RPM-PLGA-NPs in a dose-dependent manner. DNA electrophoresis showed DNA ladder in RPM and RPM-PLGA-NPs groups and classical scalar strips in control groups. The apoptotic indexes of RPM 100 ng/ml group and RPM-PLGA-NPs 500 ng/ml group detected by flow cytometry were(45.45<2.36)% and(35.04<5.64)%,respectively,which were significantly higher than that of M231-smooth muscle growth supplements control group [(2.60<0.95)%,all P<0.01]. The apoptotic indexes of groups incubated with RPM and RPM-PLGA-NPs for 24 hours were significantly higher than those of groups which incubated for 12 hours(P<0.05,P<0.01). The positive expression indexes(PEI)of p27(kip1) and bcl-2 protein were higher in RPM and RPM-PLGA-NPs groups than that of control groups. The Spearman's rank correlation coefficient test showed that there was no significant correlation between the PEI of p27(kip1) and the apoptotic indexes in the RPM group and RPM-PLGA-NPs group(P>0.05). Rapamycin-loaded PLGA nanoparticles and rapamycin have similar effects in inhibiting proliferation and inducing apoptosis;meanwhile,they upregulate the expression of p27(kip1) protein without downregulating the expression of bcl-2 protein in HUASMCs in vitro. RPM-PLGA-NPs has more potent pro-apoptotic effect than equivalent dose of RPM but is not linearly correlated with the p27(kip1) expression level.

Chrysin suppresses achaete-scute complex-like 1 and alters the neuroendocrine phenotype of carcinoids.

Carcinoids are neuroendocrine neoplasms that cause significant morbidity and mortality, and for which few effective therapies are available. Given the recent identification of the anti-cancer flavonoid chrysin, we sought to investigate its therapeutic potential in carcinoids. Here, we report chrysin’s ability to modulate the achaete-scute complex-like1 (ASCL1), a neuroendocrine-specific transcription factor highly implicated in the malignant phenotype of carcinoids and other neuroendocrine cancers. Moreover, we elucidate the role of ASCL1 in carcinoid growth and bioactivity. Treatment of two carcinoid cell lines (BON and H727) with varying chrysin concentrations suppressed cell proliferation, while reducing expression of ASCL1 and the neuroendocrine biomarker chromogranin A (CgA), demonstrated by Western blotting. Propidium iodide and PE AnnexinV/7-AAD staining and sorting following chrysin treatment revealed S/G2 phase arrest and apoptosis, respectively. This was corroborated by chrysin-induced cleavage of caspase-3 and PARP and activation of p21Waf1/Cip1. Furthermore, direct ASCL1 knockdown with an ASCL1-specific small interfering RNA inhibited CgA and synaptophysin expression as well as carcinoid proliferation, while also reducing cyclin B1 and D1, and increasing p21Waf1/Cip1 and p27Kip1 expression, suggesting an arrest of the cell-cycle. Collectively, these findings warrant the deliberation of targeted ASCL1 suppression by chrysin or other agents as a therapeutic approach for carcinoid management.

Overexpression of TRIP6 promotes tumor proliferation and reverses cell adhesion-mediated drug resistance (CAM-DR) via regulating nuclear p27(Kip1) expression in non-Hodgkin's lymphoma.

Recent studies have identified that thyroid hormone receptor-interacting protein 6 (TRIP6) is implicated in tumorigenesis. However, the functional role of TRIP6 in non-Hodgkin's lymphoma (NHL) has never been elucidated. In this study, we demonstrated that TRIP6 is reversely correlated with the clinical outcomes of NHL patients. Western blot and immunohistochemical analysis revealed that TRIP6 expression is lower in indolent lymphoma than in progressive lymphoma. Kaplan-Meier survival curves indicated that the upregulation of TRIP6 is significantly associated with poor overall survival. Moreover, patients with higher expression of TRIP6 are prone to shorter time to recurrence. Furthermore, we also found that TRIP6 can promote the proliferation of NHL cells via regulating cell cycle progression. In addition, adhesion of lymphoma cells to fibronectin (FN) decreased TRIP6 expression, which led to the upregulation of nuclear p27(Kip1) expression by decreasing phosphorylation of p27(Kip1) at T157. Importantly, overexpression of TRIP6 can reverse cell adhesion-mediated drug resistance (CAM-DR) phenotype in NHL. In summary, these results suggest that TRIP6 is a novel prognostic indicator for NHL patients and may shed new insights into the important role of TRIP6 in cancer development.

The prognostic of p27(kip1) in ovarian cancer: a meta-analysis.

P27(kip1) is a negative cell cycle regulator that plays an important role in tumor suppression. Deregulation of p27(kip1) is commonly observed in many human cancers. Numerous studies about p27(kip1) are reported in clinical patients despite variable data for the prognostic of p27(kip1) expression. Here we report a meta-analysis of the association of p27(kip1) expression with the survival of ovarian cancer. PubMed and Web of science were searched for studies evaluating expression of p27(kip1) and prognostic in ovarian cancer. Published data were extracted and computed into odds ratios (ORs) for death at 3 and 5 years. Data were pooled using the random-effect model. All statistical tests were two-sided. Analysis included 9 studies: six studies were reported in European, three studies were reported in American, and one study was reported in Asian. Loss of p27(kip1) was associated with worse overall survival (OS) at both 3 years [OR = 2.61, 95 % confidence interval (CI) 1.95-3.49, p < 0.05] and 5 years (OR = 3.01, 95 % CI 2.17-4.17, p < 0.05). Among studies with different ethnicity (European, American and Asian), the results showed a more significant association in European, including Italy, Germany, and Greece [for both 3-year OS (OR = 3.53, 95 % CI 2.37-5.26) and 5-year OS (OR = 3.66, 95 % CI 2.30-5.83)]. Loss of p27(kip1) is associated with worse survival in ovarian cancer. The development of strategies target p27(kip1) could be a reasonable therapeutic approach.

Depletion of p18/LAMTOR1 promotes cell survival via activation of p27(kip1) -dependent autophagy under starvation.

The MAPK and mTOR signal pathways in endosomes or lysosomes play a crucial role in cell survival and death. They are also closely associated with autophagy, a catabolic process highly regulated under various cellular stress or nutrient deprivation. Recently we have isolated a protein, named p18/LAMTOR1, that specifically regulates the ERK or mTOR pathway in lysosomes. p18/LAMTOR1 also interacts with p27(kip1) . Here we examined how p18/LAMTOR1 plays a role in autophagy under nutrient deprivation. The p18(+/+) MEF cells were more susceptible to cell death under starvation or in the presence of AICAR in comparison with p18(-/-) MEF cells. Cleavage of caspase-3 was increased in p18(+/+) MEF cells under starvation, and phosphorylation at the threonine 198 of p27(kip1) was highly elevated in starved p18(-/-) MEF cells. Furthermore, LC3-II formation and other autophagy-associated proteins were largely increased in p18-deficient cells, and suppression of p27(kip1) expression in p18(-/-) MEF cells mitigated starvation-induced cell death. These data suggest that ablation of p18/LAMTOR1 suppresses starvation-induced cell death by stimulating autophagy through modulation of p27(kip1) activity.

Zinc deficiency impairs the renewal of hippocampal neural stem cells in adult rats: involvement of FoxO3a activation and downstream p27kip1 expression

Zinc plays an important role in the development and maintenance of central neural system. Zinc deficiency has been known to alter normal brain function, whose molecular mechanism remains largely elusive. In the present study, we established a zinc deficiency-exposed rat model, and, using western blot and immunohistochemical analyses, found that the expression of FoxO3a and p27(kip1) was remarkably up-regulated in the rat brain hippocampus. Immunofluorescence assay showed that FOXO3a and p27(kip1) were significantly co-localized with nestin, the marker of neural stem cells (NSCs). Furthermore, we identified that the proportion of proliferating NSCs was markedly decreased in zinc-deficient rat hippocampaus. Using C17.2 neural stem cells, it was revealed that exposure to zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethy) ethylenediamine induced the expression of FoxO3a and p27(kip1) , which coincided with reduced NSC proliferation. Furthermore, depletion of FoxO3a inhibited p27(kip1) expression and restored the growth of NSCs. On the basis of these data, we concluded that FoxO3a/p27(kip1) signaling might play a significant role in zinc deficiency-induced growth impairment of NSCs and consequent neurological disorders. We describe here that zinc deficiency induces the proliferative impairment of hippocampal neural stem cells partially through the activation of FOXO3a-p27 axis in rats. Neural progenitor cells exhibited significantly up-regulated expression of FOXO3a and p27 after zinc deficiency in vivo and in vitro. Depletion of FOXO3a ameliorates zinc deficiency-induced expression of p27 and growth impairment of neural stem cells. We provide novel insight into the mechanisms underlying zinc deficiency-induced neurological deficits.

PTEN/Akt-p27kip1Signaling Promote the BM-MSCs Senescence and Apoptosis in SLE Patients

Recent studies showed that allogeneic bone marrow (BM)-mesenchymal stem cells transplantation (MSCT) was effective in systemic lupus erythematosus (SLE) patients and lupus-prone mice. However, syngeneic BM-MSCT was ineffective. Previous studies, including ours, revealed that BM-MSCs from SLE patients exhibited early signs of senescence and apoptosis such as slow proliferation, increasing senescence-associated β-galactosidase (SA-β-gal)-positive cells and Annexin V-positive cells, and caspase cascade activation. The abnormalities of BM-MSCs might be associated with the pathogenesis of SLE. In this study, we aimed to determine the molecular mechanism of senescent BM-MSCs from SLE patients. We found that the expression of protein 27 kinase inhibition protein 1(p27(kip1) ) increased significantly, which was regulated by phosphatase and tensin homology deleted on chromosome 10 (PTEN)/protein kinase B (Akt) signaling in SLE BM-MSCs. Knockdown of PTEN or p27(kip1) could reverse the senescent features of BM-MSCs via down-regulating p27(kip1) expression. When purified CD4(+) T cells were incubated with PTEN or p27(kip1) -silenced SLE BM-MSCs, the ratio of regulatory T (Treg)/T helper type 17 (Th17) cells increased significantly by enhancing regulatory cytokines (IL-10 and TGF-β) and reducing pro-inflammatory cytokines (IL-17 and IL-6). Taken together, we demonstrated that PTEN/Akt signaling played an essential role in the senescent and apoptotic BM-MSCs from SLE patients by up-regulating p27(kip1) expression.

P27kip1 overexpression regulates VEGF expression, cell proliferation and apoptosis in cell culture from eutopic endometrium of women with endometriosis.

We hypothesized that p27(kip1) overexpression can regulate endometriosis cell proliferation, apoptosis and vascular endothelial growth factor (VEGF) expression in the endometrium. The overexpression of p27(kip1) was obtained by transduction of p27(kip1) in primary cultures of endometrium obtained from women with endometriosis tissue with gene therapy technology. First generation bicistronic adenovirus: AdCMVhp27IRESEGFP (Adp27) and AdCMVNull (AdNull) were engineered in order to induce p27(kip1) expression in endometrial cells primary culture. The effect of p27(kip1) overexpression was elucidated through the cell proliferation evaluation and the expression of the cell cycle-related proteins p16, p21, p27, and p53. Cell cycle and apoptosis in endometrial cells from women with and without endometriosis were also evaluated. The VEGF levels were evaluated 1 and 7 days after transduction. The experiments were performed using Immunofluorescence stainings and flow cytometry technique. The cell proliferation statistically diminished markedly following p27(kip1) overexpression in the endometriosis group. This process was accompanied, however, by a statistically significant modulation of the cell cycle-related proteins p16, p21, p27 and p53 markedly increase following p27(kip1) overexpression in the endometriosis group (p < 0.001) and an increase in apoptotic cells was observed. In the endometriosis group, significant downregulation of VEGF expression was observed 7 days after p27(kip1) overexpression, attaining levels strikingly similar to those observed in the control endometrial cells. The findings of this study showed a link between the cell cycle control protein (p27(kip1)) and angiogenesis (VEGF). Our results, also reinforces the background of endometrial dysfunction as part of the origin of endometriosis. We believe that better knowledge of endometrium milieu and the establishment of the link between different, previously describe, altered pathways in this tissue can facilitate future genetic cell therapy.