P16 Protein Expression Levels Research Articles

Construction a novel osteoporosis model in immune-deficient mice with natural ageing

Osteoporosis (OP) predominantly affects elderly individuals. Stem cells show potential for treating OP. However, animal models with normal immune function can eliminate implanted human cells. This study utilized naturally aging NOD/SCID mice, which exhibit immunodeficiency, to create a human osteoporosis model. This approach helps to minimize the premature immune clearance of transplanted allogeneic or xenogeneic cells in preclinical studies, allowing for a more accurate replication of the clinical pharmacological and pharmacokinetic processes involved in stem cell interventions for osteoporosis. NOD/SCID mice were fed until 12, 32, and 43 weeks of age, respectively, and then euthanized. We harvested lumbar vertebra for Micro‐Computed Tomography (Micro-CT) scanning and pathological examination. Additionally, we performed biomechanical testing of lumbar vertebra to assess the severity of osteoporosis. We utilized real-time RT-PCR to assess gene expression changes associated with bone metabolism, aging, inflammation, oxidative stress, and the Tgf-β1/Smad3 signaling pathway. In addition, the protein expression levels of P16, Tgf-β1 and Smad3 were detected using Western Blotting (WB). In comparison to 12-week-old mice, the 32-week-old and 43-week-old mice displayed significantly sparser and fractured trabeculae in their lumbar vertebra, lower bone mineral density (BMD), and changes in bone microstructural parameters (**P<0.01, ***P<0.001). Additionally, compared to 12-week-old mice, the 32-week-old and 43-week-old mice exhibited decreased expression of osteogenic genes (Alp, Opg, Sp7, Col1a1), increased expression of osteoclastic gene (Rankl), the number of TRAP-positive osteoclasts significantly increased in 32-week-old and 43-week-old mice compared to 12-week-old mice. The expression of genes related to aging and inflammatory (P16, Il-1β, Tnf-α) increases with advancing age (*P<0.05, **P<0.01, ***P<0.001). The expression of oxidative stress-related genes (Sod1, Sod2, Foxo3, Nrf2), as well as Tgf-β1 and Smad3 decreased with age (*P<0.05, **P<0.01, ***P<0.001). As age increases, the levels of P16 protein increase, Tgf-β1 and Smad3 proteins decrease. Our study successfully replicated osteoporosis models in NOD/SCID mice at both 32 and 43 weeks, with the latter exhibiting more severe osteoporosis. This condition seems to be driven by factors such as aging, inflammation, oxidative stress, and the Tgf-β1/Smad3 signaling pathway.

Gastrodin alleviates premature senescence of vascular endothelial cells by enhancing the Nrf2/HO-1 signalling pathway.

Endothelial dysfunction is an independent risk factor for stroke. The dysfunction of endothelial cells (EC) is closely concerned with EC senescence. Gastrodin (GAS) is an organic compound extracted from the dried root mass of the Orchidaceae plant Gastrodiae gastrodiae. It is used clinically to treat diseases such as vertebrobasilar insufficiency, vestibular neuronitis and vertigo. In the present study, we used hydrogen peroxide (H2 O2 )-induced human umbilical vein endothelial cells (HUVECs) to establish an invitro EC senescence model and to investigate the role and mechanism of GAS in EC senescence. It's found that H2 O2 -treated HUVECs increased the proportion of senescence-associated β-galactosidase (SA β-gal) positive cells and the relative protein expression levels of senescence-associated cyclin p16 and p21. In addition, GAS reduced the proportion of SA β-gal positive cells and the relative protein expression levels of p16 and p21, and increased the proliferation and migration ability of HUVECs. Meanwhile, GAS increased the expression of the anti-oxidative stress protein HO-1 and its nuclear expression level of Nrf2. The anti-senescence effect of GAS was blocked when HO-1 expression was inhibited by SnPPIX. Furthermore, absence of HO-1 abolished the effect of GAS on HUVEC proliferation and migration. In conclusion, GAS ameliorated H2 O2 -induced cellular senescence and enhanced cell proliferation and migration by enhancing Nrf2/HO-1 signalling in HUVECs. These findings of our study expanded the understanding of GAS pharmacology and suggested that GAS may offer a potential therapeutic agent for stroke.

Effect and mechanism of Dahuang Zhechong Pills in improving liver aging in rats by regulating ROS-mediated PI3K/Akt/FoxO4 signaling pathway

Recent studies have shown that the occurrence and development of common liver diseases, including non-alcoholic fatty liver disease, cirrhosis, and liver cancer, are related to liver aging(LA). Therefore, to explore the effect and mechanism of Dahuang Zhechong Pills(DHZCP), a traditional classic prescription in improving LA with multiple targets, the present study randomly divided 24 rats into a normal group, a model group, a DHZCP group, and a vitamin E(VE) group, with six rats in each group. The LA model was induced by continuous intraperitoneal injection of D-galactose(D-gal) in rats. For the LA model rats, the general situation was evaluated by aging phenotype and body weight(BW). LA was assessed by the pathological characteristics of hepatocyte senescence, hepatic function indexes, the staining characteristics of phosphorylated histone family 2A variant(γ-H2AX), and the expression levels of cell cycle arrest proteins(P21, P53, P16) and senescence-associated secretory phenotype(SASP) in the liver. The activation of the reactive oxygen species(ROS)-mediated phosphatidylinositol-3 kinase(PI3K)/protein kinase B(Akt)/forkhead box protein O4(FoxO4) signaling pathway was estimated by hepatic ROS expression feature and the protein expression levels of the key signaling molecules in the PI3K/Akt/FoxO4 signaling pathway. The results showed that after the treatment with DHZCP or VE for 12 weeks, for the DHZCP and VE groups, the characterized aging phenotype, BW, pathological characteristics of hepatocyte senescence, hepatic function indexes, relative expression of ROS in the liver, protein expression levels of key signaling molecules including p-PI3K, p-Akt, and FoxO4 in the liver, staining characteristics of γ-H2AX, and the protein expression levels of P16, P21, P53, interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α) in the liver were improved, and the effects of DHZCP and VE were similar. Based on the D-gal-induced LA model in rats, this study demonstrates that DHZCP can ameliorate LA with multiple targets in vivo, and its effects and mechanism are related to regulating the activation of the ROS-mediated PI3K/Akt/FoxO4 signaling pathway in the liver. These findings are expected to provide new pharmacological evidence for the treatment of DHZCP in aging-related liver diseases.

Tensin Regulates Fundamental Biological Processes by Interacting with Integrins of Tonsil-Derived Mesenchymal Stem Cells.

Human tonsil-derived mesenchymal stem cells (TMSCs) have a superior proliferation rate and differentiation potential compared to adipose-tissue-derived MSCs (AMSCs) or bone-marrow-derived MSCs (BMSCs). TMSCs exhibit a significantly higher expression of the tensin3 gene (TNS3) than AMSCs or BMSCs. TNS is involved in cell adhesion and migration by binding to integrin beta-1 (ITG β1) in focal adhesion. Here, we investigated the roles of four TNS isoforms, including TNS3 and their relationship with integrin in various biological processes of TMSCs. Suppressing TNS1 and TNS3 significantly decreased the cell count. The knockdown of TNS1 and TNS3 increased the gene and protein expression levels of p16, p19, and p21. TNS1 and TNS3 also have a significant effect on cell migration. Transfecting with siRNA TNS3 significantly reduced Oct4, Nanog, and Sox-2 levels. Conversely, when TNS4 was silenced, Oct4 and Sox-2 levels significantly increase. TNS1 and TNS3 promote osteogenic and adipogenic differentiation, whereas TNS4 inhibits adipogenic differentiation of TMSCs. TNS3 is involved in the control of focal adhesions by regulating integrin. Thus, TNS enables TMSCs to possess a higher proliferative capacity and differentiation potential than other MSCs. Notably, TNS3 plays a vital role in TMSC biology by regulating ITGβ1 activity.

Cycloastragenol and Astragaloside IV activate telomerase and protect nucleus pulposus cells against high glucose-induced senescence and apoptosis.

In diabetes-induced intervertebral disc degeneration (Db-IVDD), senescence and apoptosis of nucleus pulposus cells (NPCs) are major contributing factors. Telomere attrition and telomerase downregulation are some of the main reasons for senescence and eventual apoptosis. The derivatives of the Chinese herb Astragalus membranaceus, Cycloastragenol (CAG) and Astragaloside IV (AG-IV), are reportedly effective telomerase activators against telomere shortening; however, their effect in Db-IVDD have not been explored. The present study simultaneously investigated the regulation of these derivatives on senescence, apoptosis, telomeres and telomerase a model of high-glucose (HG)-induced stress using rat primary NPCs. The NPCs were stimulated with HG (50 mM) to evoke HG-induced stress, and the effects of CAG and AG-IV were observed on: i) The expression level of senescence marker p16; ii) β-Gal staining; iii) the expression levels of apoptosis markers cleaved-caspase 3 (c-C3), BAX and Bcl-2; iv) telomerase activation with telomerase reverse transcriptase (TERT) mRNA and protein expression, while telomere length was measured with reverse transcription-quantitative PCR. Cell proliferation was determined using the Cell Counting Kit-8 assay. Results demonstrated an upregulation in the expression levels of p16, c-C3 and BAX, and increased β-Gal staining; while the expression level of Bcl-2 was downregulated in a concentration-dependent manner. Pre-treatment of the NPCs with CAG and AG-IV downregulated the protein expression levels of p16, c-C3 and BAX, and decreased the percentage of β-Gal and FITC staining; while upregulating the Bcl-2 expression. These effects protected the cells from HG stress-induced senescence and apoptosis. HG also downregulated the expression profile of TERT and shortened the telomere length in a glucose concentration-dependent manner. While pretreatment with CAG and AG-IV upregulated TERT expression and ameliorated the telomere attrition. CAG and AG-IV also increased cell proliferation and improved cell morphology in HG conditions. Overall, these findings indicated that CAG and AG-IV suppressed HG stress-induced senescence and apoptosis, in addition to enhancing telomerase activation and lengthening of the Telomere. Therefore, CAG and AG-IV prolonged the replicative capability and longevity of the NPCs and they have the potential to be therapeutic agents in Db-IVDD.

Effects of the p16/cyclin D1/CDK4/Rb/E2F1 pathway on aberrant lung fibroblast proliferation in neonatal rats exposed to hyperoxia.

p16INK4a (p16) inhibits the vital G1 to S phase transition during cell cycle progression through the p16/cyclin D1/CDK4/retinoblastoma(Rb)/E2F1 pathway. Hyperoxia can suppress the G1/S checkpoint and induce more lung fibroblasts (LFs) to transition from the G1 phase to the S phase and undergo cell proliferation. The present study investigated the rate of p16 gene promoter methylation and the protein expression levels of p16, cyclin D1, CDK4, Rb and E2F1 in LFs from the lungs of rats exposed to hyperoxia and normoxia on postnatal days 3, 7 and 14. In the hyperoxia-exposed group, the methylation rate was 50 and 80% on days 7 and 14, respectively. Cyclin D1 and CDK4 overexpression was associated with p16 loss and Rb inactivation by phosphorylation. Rb phosphorylation induced E2F1 release in the G1 phase, which promoted cell proliferation. No methylation was observed in the normoxia-exposed group. These observations suggested that p16 loss may stimulate aberrant LF proliferation via the p16/cyclin D1/CDK4/Rb/E2F1 pathway.

Palbociclib induces cell cycle arrest and senescence of human renal tubular epithelial cells in vitro

To investigate the effect of palbociclib on cell cycle progression and proliferation of human renal tubular epithelial cells. Human renal tubular epithelial cell line HK-2 was treated with 1, 5, 10, and 20 μmol/L of palbociclib, and the changes in cell proliferation and viability were examined by cell counting and CCK8 assay. EDU staining was used to assess the proliferation of HK-2 cells following palbiciclib treatment at different concentrations for 5 days. The effect of palbociclib on cell cycle distribution of HK-2 cells was evaluated using flow cytometry. SA-β-Gal staining and C12FDG senescence staining were used to detect senescence phenotypes of HK-2 cells after palbociclib treatment at different concentrations for 5 days. The relative mRNA expression levels of P16, P21, and P53 and the genes associated with senescence-related secretion phenotypes were detected by RT-PCR, and the protein expressions of P16, P21 and P53 were detected by Western blotting. Palbociclib inhibited HK-2 cell proliferation and induced cell cycle arrest in G1 phase. Compared with the control cells, HK-2 cells treated with high-dose (10 μmol/L) palbociclib exhibited significantly suppressed cell proliferation activity, and the inhibitory effect was the most obvious on day 5 (P < 0.01). Palbociclib treatment significantly reduced the number of cells in S phase (P < 0.01) and induced senescence of HK-2 cells. The results of SA-β-Gal and C12FDG senescence staining showed a significantly enhanced activity of intracellular senescence-related galactosidase in palbociclib-treated HK-2 cells, suggesting significant senescence of the cells (P < 0.01). RT-PCR and Western blotting showed that palbociclib treatment significantly increased the mRNA and protein expression levels of P16, P21, and P53 in HK-2 cells (P < 0.01); the mRNA expression levels of senescence-related secretory factors also increased significantly in HK-2 cells after palbociclib treatment (P < 0.01). Palbociclib induces HK-2 cell senescence by causing cell growth arrest and delaying cell cycle progression.

Transcription factor HBP1: A regulator of senescence and apoptosis of preadipocytes

Background/aim: HMG-box protein 1 (HBP1) plays an important role in the senescence and apoptosis of mammalian cells, but its role in chicken cells remains unclear. The aim of this study was to investigate the effects of HBP1 on senescence and apoptosis of chicken preadipocytes. Methods: The immortalized chicken preadipocyte cell line (ICP2) was used as a cell model. Chicken HBP1 knockout and overexpressing preadipocyte cell lines were established using CRISPR/Cas9 gene editing technology and lentiviral infection. Western blotting was used to detect the protein expression of HBP1 and senescence markers p16 and p53. Cell senescence was measured by Sa-β-Gal staining and apoptosis was detected by flow cytometry. Results: HBP1 was highly expressed in senescent ICP2 cells compared with young ICP2 cells. After the deletion of HBP1, the degree of senescence, the apoptosis rate and the protein expression levels of p16 and p53 were significantly reduced. After the overexpression of HBP1, the degree of senescence, the apoptosis rate and the protein expression levels of p16 and p53 were significantly increased. Conclusion: HBP1 promotes the senescence and apoptosis of chicken preadipocytes.

Correlation of p16 and nm23-H1 expression levels with incidence and prognosis of soft tissue sarcoma.

The expression levels of p16 and nm23-H1 genes in soft tissue sarcoma (STS) were evaluated to investigate correlation of the expression levels with the incidence and prognosis of STS. Tumor tissues and para-carcinoma normal tissues were collected from 64 STS patients. The messenger ribonucleic acid (mRNA) expression levels of p16 and nm23-H1 in the tissues were detected via reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and the protein expression levels of p16 and nm23-H1 in tissues were detected using immunohistochemistry. Spearman's correlation analysis was used for the correlation between expression levels of p16 and nm23-H1 in STS tissues and the correlation between p16 and nm23-H1 mRNA and protein expression. Moreover, the correlation of p16 and nm23-H1 expression levels in tumor tissues with pathological parameters and prognosis of STS patients were analyzed combined with clinical data. Results of RT-qPCR showed that mRNA expression levels of p16 and nm23-H1 in tumor tissues of STS patients were significantly lower than those in para-carcinoma normal tissues (P<0.01). Results of immunohistochemistry showed that the positive expression rates of p16 and nm23-H1 in tumor tissues of STS patients (43.75 and 39.06% respectively) were significantly lower than those in para-carcinoma normal tissues (85.93 and 89.06% respectively). The expression of p16 and nm23-H1 mRNA was positively correlated with protein expression levels. There was a positive correlation between the expression levels of p16 and nm23-H1 in tumor tissues of STS patients. The negative expression of p16 in tumor tissues of STS patients correlated with tumor size, tumor metastasis and clinical staging, and the negative expression of nm23-H1 correlated with tumor metastasis and clinical staging. The overall 5-year survival rate of patients was 54.68%, and the prognosis of patients with positive expression levels of p16 and nm23-H1 was better. Univariate survival analyses revealed that p16 and nm23-H1 were influencing factors of the overall survival rate of STS patients. p16 and nm23-H1 expression in STS is low, and their expression levels are closely related to the pathological parameters and prognosis of STS patients, so they can serve as reference indexes for prognosis estimation of STS.

Abstract 5518: Bi-allelic loss of CDKN2A initiates melanoma invasion and metastasis via E2F1-BRN2 axis

Abstract CDKN2A acts as a critical tumor suppressor in melanoma, as evidenced by frequent loss of function mutations and deletion. Loss of CDKN2A is believed to permit escape from senescent pre-neoplastic cell populations through relieve of a cell cycle block mediated by its two gene products. We performed a comprehensive analysis of CDKN2A gene status, mRNA and protein expression levels of p16 and p14 in a cohort of melanomas and their adjacent pre-neoplastic lesions and observed that bi-allelic CDKN2A loss coincides with the progression stage when primary melanomas become invasive. In melanoma lines, p16INK4A, one of the protein products of the CDKN2A locus, is a potent barrier to metastasis, independent of its known role inhibiting cell proliferation. We genetically engineered primary human melanocytes to harbor CDKN2A deletions and/or BRAF V600E mutation at their endogenous BRAF locus. Using this physiologic model for the early phases of neoplastic transformation, we found no evidence for BRAF-induced senescence, rather observing that p16INK4A loss activates a master regulator of melanoma invasion, BRN2, through Rb-E2F1 pathway. These results demonstrate that one of the most frequently altered genes across human cancers, CDKN2A, has an unexpected novel role in inhibiting cellular invasion through lineage specific transcription factors and acts as an essential gatekeeper of early metastatic dissemination. Citation Format: Hanlin Zeng, Aparna Jorapur, A. Hunter Shain, Ursula E. Lang, Rodrigo Torres, Yuntian Zhang, Thomas Botton, Jue Lin, Andrew S. Mcneal, Matthew Donne, Ingmar N. Bastian, Jeffrey North, Laura Pincus, Richard Yu, Beth S. Ruben, Nancy Joseph, Iwei Ye, Boris C. Bastian, Robert L. Judson. Bi-allelic loss of CDKN2A initiates melanoma invasion and metastasis via E2F1-BRN2 axis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5518.

CDKN2A Copy Number Loss Is an Independent Prognostic Factor in HPV-Negative Head and Neck Squamous Cell Carcinoma.

HPV infection is associated with high p16 expression and good prognosis in head and neck squamous cell carcinomas (HNSCCs). Analysis of CDKN2A, the gene encoding p16, may further elucidate the association between p16 expression and prognosis. We sought to determine whether CDKN2A copy number loss was associated with poor survival in HPV-negative HNSCCs. The Cancer Genome Atlas HNSCC clinical and genomic data were obtained and integrated. Patients <80 years old with a primary tumor in the oral cavity, oropharynx, hypopharynx, or larynx were included. Stratifying by copy number loss status, CDKN2A mRNA and p16 protein expression levels were examined and overall survival (OS) and disease-free survival (DFS) were evaluated. 401 patients with HPV-negative HNSCC were identified. 146 patients demonstrated CDKN2A copy number loss. The CDKN2A copy number loss group expressed significantly lower levels of CDKN2A mRNA and p16 protein than did the non-copy number loss group. Median OS for patients with and without CDKN2A copy number loss was 16.5 and 46.6 months, respectively (p = 0.007). Median DFS for both groups was 11.6 and 19.2 months, respectively (p = 0.03). In both univariate and multivariable analyses, stage IV designation, receipt of chemotherapy and CDKN2A copy number loss were predictive of OS. CDKN2A copy number loss predicted poor survival independently of other patient and treatment factors and may be a clinically useful prognostic factor.

CDKN2A copy number loss in HPV- and HPV+ head and neck cancer to indicate poor prognosis: An integrated genomic and clinical TCGA analysis.

6060 Background: HPV infection is associated with high p16 expression and relatively good prognosis in head and neck cancers. Analysis of CDKN2A, the gene that encodes the p16 tumor suppressor protein, may further elucidate the association between HPV status and prognosis in head and neck squamous cell carcinomas (HNSCCs). We aimed to identify whether CDKN2A copy number loss was associated with poor survival in HNSCCs stratified by HPV status. Methods: We analyzed The Cancer Genome Atlas (TCGA) head and neck cancer data, integrating genomic measurements with clinical metadata. Patients 85 years old or younger with a primary tumor in the oral cavity, oropharynx, hypopharynx, or larynx were included. Defining CDKN2A copy number loss as a relative log2 copy number ratio &lt; −0.6, CDKN2A mRNA and p16 protein expression levels were compared to confirm significant differences in gene transcription and translation between the copy number loss and non-copy number loss patient groups. Overall survival (OS) and disease-free survival (DFS) were evaluated to characterize prognostic differences between genomic groups. Results: 397 patients negative for HPV (HPV−) and 91 patients positive for HPV (HPV+) HNSCC were identified. 139 HPV− patients and 9 HPV+ patients demonstrated CDKN2A copy number loss. The CDKN2A copy number loss group expressed significantly lower levels of CDKN2A mRNA and p16 protein than did the non-copy number loss group in both HPV+ and HPV− disease. Median OS for HPV− patients with and without CDKN2A copy number loss was 21.8 months and 46.0 months (P = 0.02). Median DFS was 12.0 and 19.4 months respectively (P &lt; 0.05). Median OS for HPV+ patients with and without CDKN2A copy number loss was 12.7 months and 57.4 months (P = 0.004) and median DFS was 7.0 and 36.6 months respectively (P = 0.02). Conclusions: CDKN2A copy number loss was associated with low CDKN2A mRNA and p16 protein expression, with poor prognosis in terms of disease-free and overall survival.

Effects of both folic acid, p16 protein expression and their interaction on progression of cervical cancerization

Objective: To explore the effects of both folic acid, p16 protein expression and their interaction on progression of cervical cancerization. Methods: Participants were pathologically diagnosed new cases, including 80 women with normal cervical (NC), 55 patients with low-grade cervical intraepithelial neoplasia (CINⅠ), 55 patients with high-grade cervical intraepithelial neoplasia (CINⅡ/Ⅲ) and 64 patients with cervical squamous cell carcinoma (SCC). Serum folate levels were detected by microbiological assay method while p16 protein expression levels were measured by Western-blot. In vitro, cervical cancer cell lines C33A (HPV negative) and Caski (HPV16 positive) were treated with different concentrations of folate. Proliferation and apoptosis of cells and the levels of p16 protein expression were measured in groups with different folic acid concentrations. Results: Results showed that the levels of serum folate were (5.96±3.93) ng/ml, (5.08±3.43) ng/ml, (3.92±2.59) ng/ml and (3.18±2.71) ng/ml, and the levels of p16 protein were 0.80±0.32, 1.33±0.52, 1.91±0.77, and 2.09±0.72 in the group of NC, CINⅠ, CINⅡ/Ⅲ and SCC, respectively. However, the levels of serum folate decreased (trend χ2=32.71, P<0.001) and p16 protein expression increased (trend χ2=56.06, P<0.001) gradually along with the severity of cervix lesions. An additive interaction was seen between serum folate deficiency and high expression of p16 protein in the CINⅠ, CINⅡ/Ⅲ and SCC group. Results in vitro showed that, with the increase of folate concentration, the inhibition rate of cell proliferation (C33A: r=0.928, P=0.003; Caski: r=0.962, P=0.001) and the rate on cell apoptosis (C33A: r=0.984, P<0.001; Caski: r=0.986, P<0.001) all increased but the levels of p16 protein expression (C33A: r=-0.817, P=0.025; Caski: r=-0.871, P=0.011) reduced. The proliferation inhibition rate (C33A: r=-0.935, P=0.002; Caski: r=-0.963, P=0.001) and apoptosis rate of cells (C33A: r=-0.844, P=0.017; Caski: r=-0.898, P=0.006) were negatively correlated with the levels of p16 protein expression. Conclusions: Our findings indicated that both serum folate deficiency and high expression of p16 protein could increase the risk of cervical cancer and cervix precancerous lesion, and there was an additive interaction between them. Our findings suggested that folic acid supplementation could reverse the abnormal expression of p16 protein, and effectively promote apoptosis and inhibit proliferation in cervical carcinoma cells.

Highlights of This Issue

Mixed lineage leukemia (MLL) gene–associated disease accounts for more than 70% of infantile and 5% to 10% of acute leukemias and often has a poor prognosis. Although a number of microRNA signatures have been exposed using molecular profiling, only a few of them have been investigated for their regulatory mechanism in the context of MLL-associated leukemia. Bousquet and colleagues discovered a new MLL-leukemic tumor suppressor, miR-150, that exerts profound antileukemic effects in MLL-associated disease. Expression of miR-150 inhibited blast colony formation and cellular growth and induced apoptosis in vitro, whereas in vivo transplantation studies determined that miR-150 blocked the transforming properties of the MLL–AF9 fusion protein. Using genomic profiling, it was determined that miR-150 modulates an entire leukemic network and that knockdown of two newly identified miR-150 targets, Cbl and Egr2, recapitulated the mir-150–induced apoptosis. The findings of this study identify miR-150 as a potent tumor suppressor that impinges upon multiple oncogenes in MLL-associated leukemia.The key cell-cycle regulators p14ARF and p16INK4A are encoded by the IN4A–ARF locus, which is frequently altered in many cancers. It has long been suspected that the unusual organization of these two alternative transcripts from the same locus might reflect their coordinate regulation. In this Rapid Impact article, Kobayashi and colleagues demonstrate that ARF regulates p16 protein expression levels by influencing its protein stability. Notably, the reciprocal relationship of ARF and p16 is associated with disease outcome in at least two major tumor types, namely bladder and prostate. ARF regulates p16 stability through a REGγ-dependent proteasome degradation mechanism. These data provide significant insight into the coordinate roles of ARF and p16 in cancer, as well as the role of ARF-mediated regulation of proteasome degradation and cell-cycle and growth control.Helicobacter pylori bacterial infections are fairly common worldwide and are often asymptomatic but are strongly implicated in diseases involving the human gastric mucosa. However, the mechanism through which H. pylori promotes gastric disease is still unclear. Feng and colleagues show that the transcriptional activator FoxM1 is increased, whereas miR-370 is decreased as a function of human gastric disease stage. H. pylori infection or its key virulence factor CagA were sufficient to upregulate FoxM1 and downregulate the cell-cycle inhibitor p27Kip1 (CDKN1B), which promoted cellular proliferation. H. pylori and CagA increased FoxM1 expression by downregulating miR-370, which was shown to directly target FoxM1. These authors are the first to report that H. pylori or CagA may induce gastric carcinogenesis through upregulation of FoxM1 in a miR-370-dependent manner and suppress p27Kip1 to promote cellular proliferation.Lung cancer is the most common cause of cancer-related death in the world, and development of new molecular targeting drugs is urgently awaited. Systematic screening identified Ras and EF-hand domain containing (RASEF) as transactivated in the majority of lung cancers. Oshita and colleagues validate the elevated expression of RASEF in clinical lung specimens and show that its strong expression is associated with poor prognosis. Furthermore, RASEF promotes lung cancer cell growth through its interaction with extracellular signal–regulated kinase (ERK) 1/2. Critically, inhibition of the interaction between RASEF and ERK1/2 using a cellpermeable peptide, corresponding to the ERK1/2-interacting site of RASEF, suppressed growth of lung cancer cells. Overall, RASEF could be a prognostic biomarker, and its interaction with ERK 1/2 could be a new molecular target.

Lewis y Regulate Cell Cycle Related Factors in Ovarian Carcinoma Cell RMG-I in Vitro via ERK and Akt Signaling Pathways

ObjectiveTo investigate the effect of Lewis y overexpression on the expression of proliferation-related factors in ovarian cancer cells.MethodsmRNA levels of cyclins, CDKs, and CKIs were measured in cells before and after transfection with the α1,2-fucosyltransferase gene by real-time PCR, and protein levels of cyclins, CDKs and CKIs were determined in cells before and after gene transfection by Western blot.ResultsLewis y overexpression led to an increase in both mRNA and protein expression levels of cyclin A, cyclin D1 and cyclin E in ovarian cancer cells, decrease in both mRNA and protein expression levels of p16 and p21, and decrease of p27 at only the protein expression level without change in its mRNA level. There were no differences in proteins and the mRNA levels of CDK2, CDK4 and CDK6 before and after gene transfection. Anti-Lewis y antibody, ERK and PI3K pathway inhibitors PD98059 and LY294002 reduced the difference in cyclin and CKI expression caused by Lewis y overexpression.ConclusionLewis y regulates the expression of cell cycle-related factors through ERK/MAPK and PI3K/Akt signaling pathways to promote cell proliferation.

Long-term ethanol exposure causes human liver cancer cells to become resistant to mitomycin C treatment through the inactivation of bad-mediated apoptosis

The aim of this study was to test whether long-term ethanol consumption confers therapeutic resistance to human liver cancer patients infected with hepatitis B virus (HBV). Chronic ethanol-treated cells were established by consecutively culturing a human hepatocellular carcinoma cell line, Hep 3B, which contains integrated HBV sequences, for 20-40 passages with or without 10 mM ethanol (designated as E20-E40 and C20-C40, respectively). Flow cytometry analysis demonstrated that a growth promoting effect of long-term ethanol treatment was induced in the E40 cells through preferential acceleration of S-phase in these cells. Lower protein expression levels of p16, p21/Cip1, and p27/Kip1 were detected in the ethanol-treated E40 cells. We further demonstrated that long-term ethanol-treated E40 cells develop drug resistance in response to mitomycin C (MMC) treatment (>8 microM). Immunoblot analysis revealed that caspase-8-mediated mitochondrial apoptotic signals (such as Bad) were inactivated in the MMC-resistant E40 cells. Immunoprecipitation experiments demonstrated that the sequestration of phosphorylated Bad (Ser-112) through its binding with 14-3-3 was detected more profoundly in the MMC-resistant E40 cells. Next, we examined the therapeutic efficacy of MMC (10 mg MMC/kg body weight, three times per week) in severe combined immunodeficient (SCID) mice bearing E40- and C40-xenografted tumors. Significant reductions (>3-fold) in tumor growth were detected in MMC-treated C40-xenografted mice. In vivo and in vitro studies demonstrated that AKT- and extracellular signal-regulated kinase (ERK)-mediated survival factors inhibited the Bad-induced mitochondrial apoptotic signals that were involved in E40 tumor cells and that conferred resistance to MMC.

&amp;lt;italic&amp;gt;Nidus vespae&amp;lt;/italic&amp;gt; protein inhibiting proliferation of HepG2 hepatoma cells through extracellular signal-regulated kinase signaling pathways and inducing G&amp;lt;sub&amp;gt;1&amp;lt;/sub&amp;gt; cell cycle arrest

A protein named NVP(1) was isolated from Nidus vespae. The aim of the present study was to elucidate whether and how NVP(1) modulates the proliferation of HepG2 cells. NVP(1) at a concentration of 6.6 microg/ml could arrest the cell cycle at stage G1 and inhibit the mRNA expression of cyclinB, cyclinD1 and cyclinE. NVP(1) suppressed cdk2 protein expression, but increased p27 and p21 protein expression. However, NVP(1) did not alter p16 protein expression levels. NVP(1) promoted apoptosis in HepG2 cells as indicated by nuclear chromatin condensation, and in addition, the extracellular signal-regulated kinase (ERK) signaling pathway was activated. Moreover, the p-ERK protein expression level was attenuated when the HepG2 cells were pretreated with ERK inhibitor PD98059. These results demonstrate that NVP(1) inhibits proliferation of HepG2 through ERK signaling pathway. NVP(1) could be a potential drug for liver cancer.

Interrelationships among chromosome aneuploidy, promoter hypermethylation, and protein expression of the CDKN2A gene in individuals from northern Brazil with gastric adenocarcinoma

Numerical alterations of chromosome 9, the status of promoter methylation and protein expression of the CDKN2A gene (aliases include p16 and p16 INK4a ), the possible association with gain of chromosome X, and the interrelation of these findings with clinic and pathological characteristics were investigated in gastric adenocarcinomas. Fluorescence in situ hybridization analysis with centromeric DNA probes, immunohistochemical staining, and methylation-specific polymerase chain reaction assays were performed in 15 gastric adenocarcinomas samples from individuals from northern Brazil. Aneuploidies of chromosomes X and 9 were found in all samples, both intestinal and diffuse type. Monosomy of chromosome 9 and gain of a copy of chromosome X (in both sexes) were observed in 100% of cases. Hypermethylation frequency and protein expression of CDKN2A were also found in all cases analyzed. No association of genetic and epigenetic alterations with histological type, tumor aggressiveness, and invasion was found ( P > 0.05), which may be attributable to small sample size. There was a high level of association between absence of p16 protein expression levels, CDKN2A gene promote hypermethylation, and chromosome 9 aneuploidy (100% of cases). Thus, in the present samples, the apparent mechanisms behind p16 silencing include loss of chromosome 9 and promoter region hypermethylation.