Diagnostic significance of CyclinD1 and D2-40 expression for follicular neoplasm of the thyroid.

OBJECTIVES: To evaluate the expression and differential diagnostic significance of CyclinD1 and D2-40 in follicular neoplasm (FN) and other thyroid adenomatoid lesions. METHODS: A total of 144 cases of thyroid adenomatoid lesions were enrolled. Immunohistochemistry for CyclinD1 and D2-40 was performed. RESULTS: We found two patterns of CyclinD1 expression: nuclear (N) and cytoplasmic (C). The expression of N-CyclinD1 / C-CyclinD1 in FN (77.4%, 48/62; 50.0%, 31/62) was much higher than that in multinodular goiters with dominant nodules (MNG-DN) (16.4%, 10/61; 4.9%, 3/61) (p < 0.05). In contrast, the expression of D2-40 in MNG-DN (82.0%,50/61) was much higher than that in FN (4.8%, 3/62) (p < 0.05). In addition, unique staining patterns were observed: CyclinD1 showed no immunostaining only in all 8 cases of oncocytic cell tumors (OCT); D2-40 staining showed the characteristic wide distribution of lymphatic vessels in all 8 cases of poorly differentiated thyroid carcinoma (PDTC). Finally, the expression of CyclinD1 and D2-40 did not differ among follicular thyroid adenoma and follicular thyroid carcinoma / noninvasive follicular thyroid neoplasm with papillary-like nuclear features (p > 0.05). CONCLUSIONS: CyclinD1 and D2-40 are helpful diagnostic markers of FN, which can assist to discern FN from MNG-DN / OCT / PDTC.

Fukutin Protein Participates in Cell Proliferation by Enhancing Cyclin D1 Expression through Binding to the Transcription Factor Activator Protein-1: An In Vitro Study.

The causative gene of Fukuyama congenital muscular dystrophy (fukutin) is involved in formation of the basement membrane through glycosylation of alpha-dystroglycan. However, there are other proposed functions that have not been fully understood. Using cultured astrocytes (1321N1), we found nuclear localization of fukutin and a positive relationship between fukutin expression and cell proliferation. Among potential proteins regulating cell proliferation, we focused on cyclin D1, by reverse-transcription polymerase chain reaction, Western blotting, immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), and sandwich ELISA. Expression of cyclin D1 was significantly downregulated by fukutin knockdown and significantly upregulated by fukutin overexpression. Moreover, fukutin was proven to bind to the activator protein-1 (AP-1) binding site of cyclin D1 promoter, as well as the AP-1 component c-Jun. The c-Jun phosphorylation status was not significantly influenced by knockdown or overexpression of fukutin. The present results provide in vitro evidence for a novel function of fukutin, which participates in cell proliferation by enhancing cyclin D1 expression through forming a complex with AP-1. It is likely that fukutin is a potential cofactor of AP-1.

HNRNP A1 Promotes Lung Cancer Cell Proliferation by Modulating VRK1 Translation.

THeterogeneous nuclear ribonucleoprotein (HNRNP) A1 is the most abundant and ubiquitously expressed member of the HNRNP protein family. In recent years, it has become more evident that HNRNP A1 contributes to the development of neurodegenerative diseases. However, little is known about the underlying role of HNRNP A1 in cancer development. Here, we report that HNRNP A1 expression is significantly increased in lung cancer tissues and is negatively correlated with the overall survival of patients with lung cancer. Additionally, HNRNP A1 positively regulates vaccinia-related kinase 1 (VRK1) translation via binding directly to the 3' untranslated region (UTR) of VRK1 mRNA, thus increasing cyclin D1 (CCND1) expression by VRK1-mediated phosphorylation of the cAMP response element-binding protein (CREB). Furthermore, HNRNP A1 binding to the cis-acting region of the 3'UTR of VRK1 mRNA contributes to increased lung cancer cell proliferation. Thus, our study unveils a novel role of HNRNP A1 in lung carcinogenesis via post-transcriptional regulation of VRK1 expression and suggests its potential as a therapeutic target for patients with lung cancer.

Prognostic influences of BCL1 and BCL2 expression on disease-free survival in breast cancer.

We investigated the prognostic influences of BCL1 and BCL2 expression on disease-free survival in breast cancer patients. BCL1 and BCL2 expression statuses were assessed by immunohistochemistry using tissue microarrays from 393 breast cancer patients. The Kaplan-Meier estimator and log-rank test were used for survival analyses. The Cox proportional hazards model was used to calculate hazard ratio (HR) and the 95% confidence interval (CI) of survival analyses. BCL1 expression revealed no impact on survival. The high BCL2 group showed superior disease-free survival compared with the low BCL2 group (p = 0.002), especially regarding local recurrence-free survival (p = 0.045) and systemic recurrence-free survival (p = 0.002). BCL2 expression was a significant prognostic factor by univariable analysis (HR, 0.528; 95% CI, 0.353-0.790; p = 0.002) and by multivariable analysis (HR, 0.547; 95% CI, 0.362-0.826; p = 0.004). High BCL2 expression was associated with higher disease-free survival in the hormone receptor (HRc)-positive and human epidermal growth factor receptor 2 (HER2)-negative (HRc(+)/HER2(-)) subtype only (p = 0.002). The high BCL2 group was associated with positive estrogen receptor (ER), positive progesterone receptor (PR), low histologic grade, and age ≤ 50 years. BCL1 expression had no prognostic impact, but BCL2 expression was a significant independent prognostic factor. High BCL2 expression was associated with higher disease-free survival, especially regarding local recurrence and systemic recurrence. The prognostic effect of BCL2 expression was effective only in the HRc(+)/HER2(-) subtype. Favorable clinicopathologic features and a strong association with the ER/PR status could partly explain the superior prognosis of the high BCL2 group. BCL2 expression could be utilized to assess the prognosis of breast cancer patients in clinical settings.

Decreased ERß expression and high cyclin D1 expression may predict early CRC recurrence in high-risk Duke's B and Duke's C stage.

PURPOSE: Despite many known risk factors for the colorectal cancer (CRC) recurrence, significant differences in disease-free survival (DFS) impose the need to look for new explanations. This study aimed to determine the degree of expression of ERα, ERß, PR, Cyclin D1, and Bcl-2 and their association with early CRC relapse. METHODS: This retrospective study included 101 radically operated CRC patients in high-risk Duke's B and Duke's C stage. Tissue samples were retrieved from paraffin blocks and clinical and diagnostic data from medical records obtained during further clinical treatment and follow up. Patients were divided into DFS≤24 months group and DFS≥48 months group. Immunostaining of ERα, ERß, PR, Cyclin D1, and Bcl-2 was performed and analyzed. RESULTS: ERα was not expressed in all patients. ERß moderate expression was present in 25% of all patients, more often in the DFS≥48 group (p=0.001). PR and Bcl-2 showed only moderate expression in 1/5 and 1/3 of the patients, respectively, without significant difference between groups (p=0.145;p=0.566). Cyclin D1 was expressed in the whole sample of patients with strong expression statistically more often in DFS≤24 group (p=0.011) and had 5.2 higher odds of having DFS˂24 months. Moderate expression of ERß was joined with 79.2% smaller odds for shorter DFS. Advanced T stage had 11.3 times higher odds of having DFS˂24 months. CONCLUSION: Early recurrence of CRC in high-risk Duke's B and Duke's C stage relates with reduced ERß expression and the high cyclin D1 expression, so they could be considered independent prognostic factors, especially in patients in advanced T stage.

Nuclear EGFR Expression Is Associated With Poor Survival in Laryngeal Carcinoma.

The membrane EGFR (mEGFR) protein overexpression in the head and neck squamous cell carcinoma (SCC) is considered to cause increased EGFR activity which adds to tumorigenicity and therapy resistance. The mEGFR upon stimulation can translocate to the nucleus nuclear EGFR (nEGFR) where it has been associated with poor prognosis and worse survival in many cancers. The relevance of differentially located EGFR proteins in laryngeal lesions has not been studied enough and remains unclear. Aim of our study was to examine nEGFR and mEGFR protein expression as well as EGFR gene status and cell cycle proliferation markers in the laryngeal polyps, dysplasia, and SCC using immunohistochemistry and in situ hybridization. There was significantly higher frequency of strong nEGFR between SCC, dysplasia, and polyps (P<0.0001), and strong mEGFR in the SCC and laryngeal dysplasia comparing to polyps (P<0.0001). Gene amplification was confirmed only in relatively small number of SCC but not in non-neoplastic lesions. In dysplasia the statistically significant positive correlations between nEGFR, and Ki-67 (P=0.029), p53 (P=0.001), and cyclin D1 (P=0.031) were found. nEGFR and mEGFR expression showed statistically significant inverse correlation in the SCC (P=0.004) as well as nEGFR and cyclin D1 (P=0.032). Univariate statistical analysis showed statistically significant correlation between strong nEGFR protein expression and worse overall survival in laryngeal SCC, alone or in coexpression with strong cyclin D1 and high Ki-67 (P=0.025, P=0.046, P=0.043, respectively). Our data show that nEGFR cellular localization might influence biology of the laryngeal carcinogenesis and is indicator of poor survival.

FBX4 mediates rapid cyclin D1 proteolysis upon DNA damage in immortalized esophageal epithelial cells.

It has been implied that deregulation of cyclin D1 turnover under stresses can facilitate genomic instability and trigger tumorigenesis. Much focus has been placed on identifying the E3 ligases responsible for mediating cyclin D1 degradation. However, the findings were quite controversial and cell type-dependent. Little is known about how cyclin D1 is regulated in precancerous cells upon DNA damage and which E3 ligases mediate the effects. Here we found cyclin D1 reduction is an early response to DNA damage in immortalized esophageal epithelial cells, with expression dropping to a low level within 1 h after γ-irradiation. Comparison of temporal expression of cyclin D1 upon DNA damage between immortalized NE083-hTERT and NE083-E6E7, the latter being p53/p21-defective, showed that DNA damage-induced rapid cyclin D1 reduction was p53-independent and occurred before p21 accumulation. Overexpression of cyclin D1 in NE083-E6E7 cells could attenuate G0/G1 cell cycle arrest at 1 h after irradiation. Furthermore, rapid reduction of cyclin D1 upon DNA damage was attributed to proteasomal degradation, as evidenced by data showing that proteasomal inhibition by MG132 blocked cyclin D1 reduction while cycloheximide facilitated it. Inhibition of ATM activation and knockdown of E3 ligase adaptor FBX4 reversed cyclin D1 turnover in immortalized NE083-hTERT cells. Further study showed that knockdown of FBX4 facilitated DNA breaks, as indicated by an increase in γ-H2AX foci in esophageal cancer cells. Taken together, the results substantiated a pivotal role of ATM and FBX4 in cyclin D1 proteolysis upon DNA damage in precancerous esophageal epithelial cells, implying that deregulation of the process may contribute to carcinogenesis of esophageal squamous cell carcinoma.

Comparative expression profile of CD10 and cyclin D1 in cutaneous histiocytofibroma and dermatofibrosarcoma.

Dermatofibrosarcoma protuberans (DFSP) and histiocytofibroma (HF) are two rare fibrohistiocytic tumors, with some overlapping pathologic features. Immunohistochemistry is very useful in these cases. CD34 is a commonly used marker. However, the increasing cases of CD34 negative DFSP make it pressing to test other immunohistochemical markers that could help in the differential diagnosis. DFSP is known to harbor COL1A1-PDGFB rearrangement. Tumors in the differential diagnosis of DFSP usually lack this molecular signature. Recent studies suggested the interaction of PDGFB and PDGF receptor b with various signaling pathways, including the Akt-mTOR pathway. Cyclin D1, one of the oncoproteins activated in this pathway, may represent a promising useful biomarker in the differential diagnosis. On the other hand, CD10 expression in specialized mesenchymal skin cells, and especially in fibrohistiocytic skin tumors has been reported, which raises the interest of using this biomarker in HF and DFSP. In this study, we aimed to compare the expression of CD10 and cyclin D1 in 15 cases of DFSP and 15 cases of HF and discuss their potential contribution in the differential diagnosis.

Cytosolic pH regulates proliferation and tumour growth by promoting expression of cyclin D1.

Enhanced growth and proliferation of cancer cells are accompanied by profound changes in cellular metabolism. These metabolic changes are also common under physiological conditions, and include increased glucose fermentation accompanied by elevated cytosolic pH (pHc)1,2. However, how these changes contribute to enhanced cell growth and proliferation is unclear. Here, we show that elevated pHc specifically orchestrates an E2F-dependent transcriptional programme to drive cell proliferation by promoting cyclin D1 expression. pHc-dependent transcription of cyclin D1 requires the transcription factors CREB1, ATF1 and ETS1, and the histone acetyltransferases p300 and CBP. Biochemical characterization revealed that the CREB1-p300/CBP interaction acts as a pH sensor and coincidence detector, integrating different mitotic signals to regulate cyclin D1 transcription. We also show that elevated pHc contributes to increased cyclin D1 expression in malignant pleural mesotheliomas (MPMs), and renders these cells hypersensitive to pharmacological reduction of pHc. Taken together, these data demonstrate that elevated pHc is a critical cellular signal regulating G1 progression, and provide a mechanism linking elevated pHc to oncogenic activation of cyclin D1 in MPMs, and possibly other cyclin D1~dependent tumours. Thus, an increase of pHc may represent a functionally important, early event in the aetiology of cancer that is amenable to therapeutic intervention.

Brain-Derived Neurotrophic Factor Inhibits the Wound-Healing and Cell Proliferative Ability of Human Airway Epithelial Cells in Asthmatic Children.

BACKGROUND Asthma is a chronic disease with high morbidity rates. Brain-derived neurotrophic factor (BDNF) has been proven to induce airway hyper-responsiveness, but the function of BDNF in the wound-healing process of asthmatic human airway epithelial cells (HAECs) remains unclear. This study investigated the effects of BDNF in asthmatic children with injured HAECs. MATERIAL AND METHODS HAECs were obtained from healthy children and asthmatic children through bronchoscopy, and then cultured in air-liquid (ALI) interface with or without BDNF. A mechanical injury model was established for the wound-healing assay. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed to measure BDNF mRNA expressions, while western blot assay was used for the measurement of BDNF and CCND1 protein expressions. Cell proliferation of impaired HAECs was assayed in a ³H-thymidine incorporation experiment. RESULTS The mRNA and protein levels of BDNF were overexpressed, and the wound-healing ability of HAECs decreased in asthma samples. Also, the cell proliferation of HAECs was suppressed in the asthmatic injury model and the injury-induced increase of CCND1 protein expressions was inhibited in asthma. Although mRNA and protein expressions of BDNF remained unchanging in healthy HAECs, there was an increase in impaired asthmatic HAECs. Upregulating BDNF led to a decrease in wound-healing ability of HAECs in both healthy children and children with asthma. Simultaneously, overexpressed BDNF reduced the CCND1 protein expressions in healthy HAECs, but had little impact on asthmatic HAECs. CONCLUSIONS Brain-derived neurotrophic factor (BDNF) inhibited wound-healing and cell proliferative ability of human airway epithelial cells (HAECs) in asthmatic children.

Mesenchymal epithelial transition factor regulates tumor necrosis factor-related apoptotic induction ligand resistance in hepatocellular carcinoma cells through down-regulation of cyclin B1.

Tumor necrosis factor-related apoptotic induction ligand can induce cell apoptosis in various tumor cells. However, many cancer cells are resistant to tumor necrosis factor-related apoptotic induction ligand. Therefore, overcoming the tumor necrosis factor-related apoptotic induction ligand resistance makes it possible for tumor necrosis factor-related apoptotic induction ligand-based anti-cancer therapies. In this study, we took mesenchymal epithelial transition factor as the research target to study its role in tumor necrosis factor-related apoptotic induction ligand-resistant hepatocellular carcinoma. Mesenchymal epithelial transition factor gene has been proved to be an effective predictor of recurrence after hepatocellular carcinoma resection. The expression of mesenchymal epithelial transition factor and cyclin B1 were measured in tumor necrosis factor-related apoptotic induction ligand-resistant and non-resistant hepatocellular carcinoma tissues. Cyclin B1-knockdown and cyclin B1-overexpression hepatocellular carcinoma cells were treated with tumor necrosis factor-related apoptotic induction ligand; mesenchymal epithelial transition factor knockout, mesenchymal epithelial transition factor re-introduction and cyclin B1 restored in hepatocellular carcinoma cells treated with tumor necrosis factor-related apoptotic induction ligand were established. And MTT, bromodeoxyuridine, flow cytometry and western blotting were performed to evaluate the effect of mesenchymal epithelial transition factor and cyclin B1 on hepatocellular carcinoma cells treated with tumor necrosis factor-related apoptotic induction ligand. In addition, subcutaneous tumor transplantation in nude mice was conducted to access the effect of mesenchymal epithelial transition factor and cyclin B1 on tumor formation in vivo. In conclusion, cyclin B1 enhanced the cell growth and inhibited apoptosis in tumor necrosis factor-related apoptotic induction ligand-resistant hepatocellular carcinoma cells. And mesenchymal epithelial transition factor promoted the cell growth and apoptosis in tumor necrosis factor-related apoptotic induction ligand-resistant hepatocellular carcinoma cells by regulating cyclin B1. Therefore, mesenchymal epithelial transition factor regulates the cyclin B1 to regulate tumor necrosis factor-related apoptotic induction ligand resistance in hepatocellular carcinoma cells. Our results suggest a novel molecular mechanism for regulating tumor necrosis factor-related apoptotic induction ligand resistance, which might be helpful to select drug targets in the treatment of liver cancer.

The functional epigenetic landscape of aberrant gene expression in molecular subgroups of newly diagnosed multiple myeloma.

BACKGROUND: Multiple Myeloma (MM) is a hematological malignancy with genomic heterogeneity and poor survival outcome. Apart from the central role of genetic lesions, epigenetic anomalies have been identified as drivers in the development of the disease. METHODS: Alterations in the DNA methylome were mapped in 52 newly diagnosed MM (NDMM) patients of six molecular subgroups and matched with loci-specific chromatin marks to define their impact on gene expression. Differential DNA methylation analysis was performed using DMAP with a ≥10% increase (hypermethylation) or decrease (hypomethylation) in NDMM subgroups, compared to control samples, considered significant for all the subsequent analyses with p<0.05 after adjusting for a false discovery rate. RESULTS: We identified differentially methylated regions (DMRs) within the etiological cytogenetic subgroups of myeloma, compared to control plasma cells. Using gene expression data we identified genes that are dysregulated and correlate with DNA methylation levels, indicating a role for DNA methylation in their transcriptional control. We demonstrated that 70% of DMRs in the MM epigenome were hypomethylated and overlapped with repressive H3K27me3. In contrast, differentially expressed genes containing hypermethylated DMRs within the gene body or hypomethylated DMRs at the promoters overlapped with H3K4me1, H3K4me3, or H3K36me3 marks. Additionally, enrichment of BRD4 or MED1 at the H3K27ac enriched DMRs functioned as super-enhancers (SE), controlling the overexpression of genes or gene-cassettes. CONCLUSIONS: Therefore, this study presents the underlying epigenetic regulatory networks of gene expression dysregulation in NDMM patients and identifies potential targets for future therapies.

Molecular Pathogenesis of Mantle Cell Lymphoma.

Mantle cell lymphoma (MCL) is a mature B-cell neoplasm with heterogeneous clinical behavior molecularly characterized by the constitutive overexpression of cyclin D1 and deregulation of different signaling pathways. SOX11 expression determines an aggressive phenotype associated with accumulation of many chromosomal alterations and somatic gene mutations. A subset of patients with the SOX11-negative leukemic non-nodal MCL subtype follows an initial indolent clinical evolution and may not require treatment at diagnosis, although eventually may progress to an aggressive disease. We discuss the genetic and molecular alterations with impact on the cancer hallmarks that characterize the lymphomagenesis of the 2 MCL subtypes.

What Is Responsible for Heterogeneity in Mantle Cell Lymphoma Biology and Outcomes?

Mantle cell lymphoma, despite its common derivation from a t(11;14) error that occurs in a naïve B-cell leading to overexpression of cyclin D1 protein, is characterized by substantial heterogeneity in biology and clinical outcome. Unlike other non-Hodgkin lymphoma types, it is more common in men. Clinical presentation patterns vary from nodal to splenomegaly with leukemia to gastrointestinal involvement. Biological variability is linked to tumor cell proliferation. Increased monocyte/macrophages and their associated proinflammatory cytokines are associated with inferior outcomes. These clues mandate that new treatments should target signal pathways that contribute to these adverse outcomes.

The circular RNA circEIF3M promotes breast cancer progression by promoting cyclin D1 expression.

We investigated the function of circular RNA circEIF3M (hsa_circ_0003119) in triple-negative breast cancer. The expression profiles of circRNAs in 3 specimens of triple-negative breast cancer tissues with adjacent nontumor tissues were analyzed by RNA-sequencing. We verified the oncogenic role of circEIF3M in triple-negative breast cancer through a series of biological function experiments. It was found that circEIF3M was markedly upregulated in triple-negative breast cancer as compared to adjacent nontumor tissue, and that circEIF3M promoted triple-negative breast cancer cell proliferation, migration, and invasion. Mechanistic analysis indicated that circEIF3M may act as a competing endogenous RNA for miR-33a that relieves the inhibitory effect of miR-33a on its target cyclin D1. These findings showed that circEIF3M promotes triple-negative breast cancer progression via the circEIF3M/ miR-33a/ cyclin D1 axis.

Influence of Cilostazol on Changes in Cyclin D1 Expression in Cerebral Cortex of Rats with Chronic Cerebral Ischemia.

The influence of cilostazol on learning and memory, and cyclin D1 expression in the cerebral cortex of rats with chronic cerebral ischemia were investigated. A chronic cerebral ischemia model was established using the permanent bilateral common carotid artery occlusion method (2VO), learning and memory capacity was detected using the Morris water maze, and expression changes in apoptosis regulating gene cyclin D1 were tested by RT-PCR. Results of the Morris water maze indicated that significant extensions were found in the escape latent period and swimming path of rats in the ischemia group (2VO group), learning and memory results in the cilostazol group was obviously superior compared to the 2VO group (P<0.05), and the expression of cyclin D1 was observed to increase in both the ischemia and cilostazol intervention groups at the 9th week of ischemia. A significant difference was observed, compared with the sham operation group (P<0.05), the expression level decreased in the ischemia group compared with the cilostazol group, and a significant difference was identified compared with the ischemia group (P<0.05). Cilostazol can reduce nerve function impairment and improve learning and memory functions by affecting changes in apoptosis regulating genes.

Quercetin induces apoptosis and enhances gemcitabine therapeutic efficacy against gemcitabine-resistant cancer cells.

Quercetin, an abundant flavonoid found in various fruits and vegetables, displays multiple biological activities, including anticancer effects. Therefore, quercetin is receiving increasing attention as a potential adjuvant anticancer treatment. Gemcitabine (GEM) resistance is a major issue for clinicians and patients with advanced cancers, making it crucial to determine ways to bolster its effects. In this study, we explored the anticancer effects and mechanistic actions of quercetin in GEM-resistant cancer cells. Pancreatic cancer (BxPC-3, PANC-1) and hepatocellular carcinoma (HepG2, Huh-7) cell lines were studied. Proliferation assays showed that quercetin had cytotoxic effects on GEM-resistant cell lines (HepG2 and PANC-1), and flow cytometric analysis indicated a significant pro-apoptotic effect on these cell lines. GEM treatment, in combination with quercetin, resulted in increased anticancer effects compared with GEM alone. Quercetin led to S phase arrest in GEM-resistant cell lines, and western blot analysis revealed tumour protein p53 upregulation and cyclin D1 downregulation. This study provides mechanistic insight into the anticancer effects of quercetin and suggests that quercetin adjuvant treatment may benefit patients who are resistant to GEM therapy.

Tumor-specific transcript variants of cyclin D1 in mantle cell lymphoma and multiple myeloma with chromosome 11q13 abnormalities.

Cyclin D1 (CCND1) overexpression is an early and unifying oncogenic event in mantle cell lymphoma (MCL) and multiple myeloma (MM) with chromosome 11q13 abnormalities. Herein, we report newly discovered transcript variants of the CCND1 gene in MCL and MM cells with chromosome 11q13 abnormalities. These transcript variants, designated CCND1.tv., covered the full-length coding region of CCND1 with longer 5'-untranslated regions (5'-UTRs) of CCND1 and occasionally contained a novel exon. CCND1.tv. was specifically detectable in patient-derived primary MCL or MM cells with chromosomal translocation t(11;14)(q13;q32), but not in t(11;14)-negative cells. The lengths of the 5'-UTR sequences of CCND1.tv. differed among patients and cell lines. Introduction of CCND1.tv. led to increased expression of normal-sized CCND1 protein in HEK293 cells. Furthermore, mTOR inhibition by rapamycin or serum starvation reduced ectopic expression of CCND1.tv.-derived CCND1 protein, but not 5'-UTR less CCND1-derived CCND1 protein in HEK293 cells, suggesting that the protein expression of CCND1.tv. is regulated by the mTOR pathway. Our results suggest that the aberrant expression of CCND1.tv. may contribute to the understanding of the pathogenesis of MCL and MM with 11q13 abnormalities.

Rapamycin prevents retinal neovascularization by downregulation of cyclin D1 in a mouse model of oxygen-induced retinopathy.

BACKGROUND: Rapamycin (RAPA) is a potent angiogenic inhibitor and the aim of this study is to identify the inhibitory effect of RAPA on retinal neovascularization (RNV) in experimental oxygen-induced retinopathy (OIR). METHODS: Forty-two 7-day-old C57BL/6 J mice were randomly divided into normoxia control group (14 mice), OIR group (14 mice), and rapamycin (RAPA) group. OIR model was induced in OIR and RAPA group. Vehicle and RAPA (2 mg/kg/d) was injected intraperitoneally daily from postnatal day 12 (P12) in OIR and RAPA groups, respectively. RNV was evaluated using fluorescence angiography and histopathology on P17. Non-perfused areas of retina were analyzed by Image-Pro plus 6.0 software. Retinal expression of cyclin D1 was detected both at mRNA and protein levels. RESULTS: RAPA treatment significantly decreased RNV, non-perfused areas and number of endothelial cell nuclei breaking through the internal limiting membrane (ILM) in OIR mice. Moreover, RAPA decreased activation of cyclin D1 in retina caused by OIR. CONCLUSION: RAPA can inhibit RNV by downregulating the expression of cyclin D1, which indicates its therapeutic potential in treating RNV-related diseases.

circRNA-14723 promotes hepatocytes proliferation in rat liver regeneration by sponging rno-miR-16-5p.

Circular RNA (circRNA) is a subclass of noncoding RNA (ncRNA) detected within mammalian tissues and cells. However, its regulatory role during the proliferation phase of rat liver regeneration (LR) remains unreported. This study was designed to explore their regulatory mechanisms in cell proliferation of LR. The circRNA expression profile was detected by high-throughput sequencing. It was indicated that 260 circRNAs were differentially expressed during the proliferation phase of rat LR. Among them, circ-14723 displayed a significantly differential expression. We further explored its regulatory mechanism in rat hepatocytes (BRL-3A cells). First, EdU, flow cytometry and western blot (WB) indicated that knocking down circ-14723 inhibited BRL-3A cells proliferation. Second, RNA-Pulldown and dual-luciferase report assay showed that circ-14723 could sponge rno-miR-16-5p. At last, WB showed that the reported target genes of rno-miR-16-5p, CCND1, and CCNE1 were downregulated after knocking down circ-14723. In conclusion, we found that circ-14723 exerted a critical role in G1/S arrest to promote cell proliferation via rno-miR-16-5p/CCND1 and CCNE1 axis in rat LR. This finding further revealed the regulatory mechanisms of circRNA on cell proliferation of LR, and might provide a potential target for clinical problems.