Gene Summary

Gene:PCNA; proliferating cell nuclear antigen
Aliases: ATLD2
Summary:The protein encoded by this gene is found in the nucleus and is a cofactor of DNA polymerase delta. The encoded protein acts as a homotrimer and helps increase the processivity of leading strand synthesis during DNA replication. In response to DNA damage, this protein is ubiquitinated and is involved in the RAD6-dependent DNA repair pathway. Two transcript variants encoding the same protein have been found for this gene. Pseudogenes of this gene have been described on chromosome 4 and on the X chromosome. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:proliferating cell nuclear antigen
Source:NCBIAccessed: 12 March, 2017


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 12 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 12 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: PCNA (cancer-related)

Subash-Babu P, Alshammari GM, Ignacimuthu S, Alshatwi AA
Epoxy clerodane diterpene inhibits MCF-7 human breast cancer cell growth by regulating the expression of the functional apoptotic genes Cdkn2A, Rb1, mdm2 and p53.
Biomed Pharmacother. 2017; 87:388-396 [PubMed] Related Publications
Systematic analyses of plants that are used in traditional medicine may lead to the discovery of novel cytotoxic secondary metabolites. Diterpene possesses multiple bioactivities; here, epoxy clerodane diterpene (ECD) was isolated from Tinospora cordifolia (Willd.) stem and shown potential antiproliferative effect in MCF-7 human breast cancer cells. The antiproliferative effect of ECD on MCF-7 cells was systematically analyzed by cell and nuclear morphology, alterations in oxidative stress, and the expression of tumor suppressor and mitochondria-mediated apoptosis-related genes. We found that the IC50 value of ECD was 3.2μM at 24h and 2.4μM at 48h. We observed that the cytotoxicity of ECD was specific to MCF-7 cells, whereas ECD was nontoxic to normal Vero and V79 cells. ECD significantly triggered intracellular ROS generation even from the lower doses of 0.6 and 1.2μM; and it is relative to higher dose of 2.4μM. Further, we used 0.6μM, 1.2μM and 2.4μM as experimental doses to analyze the relative dose-dependent effects. Nuclear staining revealed that cells treated with the 2.4μM dose exhibited characteristic apoptotic morphological changes and that 46% of the cells were apoptotic and 4% were necrotic after 48h. ECD significantly increased the expression of mitochondria-dependent apoptotic pathway-related genes after 48h; we observed significantly (p≤0.05) increased expression of CYP1A, GPX, GSK3β and TNF-α and downregulated expression of NF-κB. ECD also increased the expression of tumor suppressor genes such as Cdkn2A, Rb1 and p53. In addition, we observed that ECD treatment significantly (p≤0.001) upregulated the expression of apoptotic genes such as Bax, cas-3, cas-8, cas-9 and p21 and downregulated the expression of BCL-2, mdm2 and PCNA. In conclusion, ECD regulates the expression of Cdkn2A, p53 and mdm2 and induces apoptosis via the mitochondrial pathway in MCF-7 human breast cancer cells.

Li X, Zhang G, Wang Y, et al.
Loss of periplakin expression is associated with the tumorigenesis of colorectal carcinoma.
Biomed Pharmacother. 2017; 87:366-374 [PubMed] Related Publications
Periplakin (PPL), a member of the plakin protein family, has been reported to be down-expressed in urothelial carcinoma. The role of PPL in human colorectal cancer, however, remains largely unknown. Also little is known about the contribution of PPL to the malignant property of colorectal cancer and the intracellular function of PPL. In this study, we demonstrated that PPL was apparently down-expressed in colon carcinomas compared with normal and para-carcinoma tissues, which was correlated with the tumor size. Enforced expression of PPL in HT29 cells inhibited its proliferation evidenced by decreased expression of phosphorylated ERK and PCNA. Furthermore, PPL overexpression could reduce metastasis and epithelial-mesenchymal transition (EMT) of HT29 cells, with decreased expression of N-cadherin, Snail, Slug and α-SMA while increased expression of E-cadherin. On the contrary, the PPL knockdown could promote the cell proliferation, migratory, invasive and EMT ability of HT29 cells. Moreover, enforced expression of PPL induced G1/G0 cell cycle arrest, with decreased cyclin D1, p-Rb and increased expression of p27(kib), which could be reversed by PPL knockdown. In addition, PPL overexpression inhibited the growth of colon cancer allograft in vivo. Taken together, acted as a tumor suppressor in colon cancer progression, PPL could be a new biomarker or potential therapeutic target in colon cancer.

Chen Y, Wang X, Duan C, et al.
Loss of TAB3 expression by shRNA exhibits suppressive bioactivity and increased chemical sensitivity of ovarian cancer cell lines via the NF-κB pathway.
Cell Prolif. 2016; 49(6):657-668 [PubMed] Related Publications
Ovarian cancer is a leading cause of death among gynaecologic malignancies. Despite many years of research, it still remains sparing in reliable diagnostic markers and methods for early detection and screening. Transforming growth factor β-activated protein kinase 1 (TAK1)-binding protein 3 (TAB3) was initially characterized as an adapter protein essential for TAK1 activation in response to IL-1β or TNFα, however, the physiological role of TAB3 in ovarian cancer tumorigenesis is still not fully understood. In this study, we evaluated the effects of TAB3 on ovarian cancer cell lines. Expressions of TAB3 and PCNA (proliferating cell nuclear antigen) were found to be gradually increased in EOC tissues and cell lines, by western blot analysis and qRT-PCR. Distribution of TAB3 was further analysed by immunohistochemistry. In vitro, knockdown of TAB3 expression in HO8910 or SKOV3 ovarian cancer cells significantly inhibited bioactivity of ovarian cancer cells, including proliferation and cell-cycle distribution, and promoted chemical sensitivity to cisplatin and paclitaxel treatment via inhibiting NF-κB pathways. In conclusion, our study strongly suggests a novel function of TAB3 as an oncogene that could be used as a biomarker for ovarian cancer. It provides a new insight into the potential mechanism for therapeutic targeting, in chemotherapy resistance, common in ovarian cancer.

Hu R, Hu F, Xie X, et al.
TMEM45B, up-regulated in human lung cancer, enhances tumorigenicity of lung cancer cells.
Tumour Biol. 2016; 37(9):12181-12191 [PubMed] Related Publications
Transmembrane protein 45B (TMEM45B) is a member of TMEMs. Altered expression of TMEMs is frequently observed in a variety of human cancers, but the expression and functional roles of TMEM45B in lung cancer is not reported. In the present study, levels of mRNA expression of TMEM45B in lung cancer tissues were assessed using re-analyzing expression data of The Cancer Genome Atlas (TCGA) lung cancer cohort and real-time PCR analysis on our own cohort. Lung cancer cells, A549 and NCI-H1975, infected with TMEM45B short hairpin RNA were examined in cell proliferation, cell cycle, cell apoptosis, wound-healing, and cell invasion assays as well as mouse xenograft models. Here, we demonstrated that TMEM45B was overexpressed in lung cancer and its expression correlated with overall survival of patients. In addition, silencing of TMEM45B expression reduced cell proliferation in vitro and in vivo, induced cell cycle arrest and cell apoptosis, and blocked cell migration and invasion. Moreover, knockdown of TMEM45B significantly suppressed G1/S transition, induced cell apoptosis, and inhibited cell invasion via regulating the expression of cell cycle-related proteins (CDK2, CDC25A, and PCNA), cell apoptosis-related proteins (Bcl2, Bax, and Cleaved Caspase 3), and metastasis-related proteins (MMP-9, Twist, and Snail), respectively. Thus, TMEM45B is a potential prognostic marker and cancer-selective therapeutic target in lung cancer.

Peng W, Jiang A
Long noncoding RNA CCDC26 as a potential predictor biomarker contributes to tumorigenesis in pancreatic cancer.
Biomed Pharmacother. 2016; 83:712-717 [PubMed] Related Publications
Pancreatic cancer (PC) is the fourth most common cancer worldwide and has the least patient survival rate of any cancer. Emerging studies have demonstrated that long noncoding RNAs (lncRNAs) were present in cancer patients and have shown great potential as powerful markers and therapeutic targets. However, little is known about the role of lncRNAs in PC. The present study aimed to investigate the expression pattern, clinical significance and biological function of lncRNA CCDC26 (CCDC26) in PC. With quantitative real-time PCR, we analyzed CCDC26 expression levels in 40 PC patients. We found that the CCDC26 expression was significantly higher in PC tissues than in normal tissues. CCDC26 levels were correlated with tumor size, tumor number, and reduced overall survival (OS). Univariate and multivariate analysis showed that CCDC26 expression is an independent prognostic factor of OS in patients with PC. Additionally, ROC(AUC) of CCDC26 was up to 0.663, implicating that CCDC26 could be a diagnostic marker for distinguishing PC from normal. Knockdown of CCDC26 expression by small interfering RNA significantly promoted growth arrest and apoptosis. Moreover, we found that the expression of CCDC26 was positively correlated with PCNA and Bcl2. Our data suggest that CCDC26 may be identified as a novel oncogene in PC, and responsible for growth and apoptosis of cancer cell, partly by regulating the PCNA and Bcl2 expression. This work provides a novel biomarker and therapeutic target of PC for cancer clinic in future.

Liu ZZ, Cui ST, Tang B, et al.
Identification of key biomarkers involved in osteosarcoma using altered modules.
Genet Mol Res. 2016; 15(3) [PubMed] Related Publications
The aim of this study was to screen for key biomarkers of osteosarcoma (OS) by tracking altered modules. Protein-protein interaction (PPI) networks of OS and normal groups were constructed and re-weighted using the Pearson correlation coefficient (PCC), respectively. The condition-specific modules were explored from OS and normal PPI networks using a clique-merging algorithm. Altered modules were identified by a maximum weight bipartite-matching method. The important biological pathways in OS were identified by a pathway-enrichment analysis using genes from disrupted modules. The most important genes in these pathways were selected as key biomarkers. Finally, the mRNA and protein expressions of hub genes in OS bone tissues were analyzed using reverse transcription-polymerase chain reaction and western blotting, respectively. We identified 703 and 2270 modules in normal and disease networks, respectively; 150 altered modules were identified from among these and explored. We identified 10 important pathways based on gene pairs with altered PCC > 1 in the disrupted modules (P < 0.01), and PCNA, ATP6V1C2, ATP6V1G3, FEN1, CDC7, and RPA3 (expressed in these pathways) were selected as key genes of OS. We observed that these genes (and the proteins they encoded) were differentially expressed between normal and OS samples (P < 0.01) (excluding ATP6V1C2, whose protein expression did not differ significantly). Therefore, we identified 5 gene signatures that may be potential biomarkers for the detection and effective therapy of OS.

Mao QQ, Chen JJ, Dong L, et al.
Krüppel-like factor 2 suppresses growth and invasion of gastric cancer cells in vitro and in vivo.
J Biol Regul Homeost Agents. 2016 Jul-Sep; 30(3):703-712 [PubMed] Related Publications
Krüppel-like factor 2 (KLF2), a novel tumor-suppressor gene, is implicated in diverse cellular processes, including cell growth, apoptosis, and invasion. However, the role and action mechanisms of KLF2 in gastric cancer (GC) need be further elucidated. The expression of KLF2 was investigated by immunohistochemical assay in human GC tissues, and lentivirus-mediated KLF2 overexpression was transfected into GC cells (AGS and HGC-27) for assessing cell proliferation and invasion, respectively indicated by MTT and Transwell assays. Subcutaneous GC tumor models were constructed for estimating tumor growth in vivo. As a result, the expression level of KLF2 was decreased in GC tissues compared with the para-carcinoma tissues (31.03% vs 53.45%, P=0.035), and negatively correlated with the lymph node metastasis in GC patients (P=0.02). Moreover, overexpression of KLF2 inhibited the cell proliferation and invasive potential and downregulated the protein expression of PCNA, Bcl-2 and MMP-9 in GC cells. The result in vivo showed KLF2 overexpression reduced the xenograft tumor growth. In conclusion, our findings indicate that KLF2 may function as a tumor suppressor involved in the progression of human GC.

Dasgupta H, Mukherjee N, Islam S, et al.
Frequent alterations of homologous recombination repair pathway in primary and chemotolerant breast carcinomas: clinical importance.
Future Oncol. 2017; 13(2):159-174 [PubMed] Related Publications
AIM: To understand the importance of homologous recombination repair pathway in development of breast carcinoma (BC), alterations of some key regulatory genes like BRCA1, BRCA2, FANCC and FANCD2 were analyzed in pretherapeutic/neoadjuvant chemotherapy (NACT)-treated BC samples.
MATERIALS & METHODS: Alterations (deletion/methylation/expression) of the genes were analyzed in 118 pretherapeutic and 41 NACT-treated BC samples.
RESULTS: High deletion/methylation (29-68%) and 64-78% overall alterations of the genes were found in the samples. Concordance was evident between alteration and protein expression of the genes. Estrogen/progesterone receptor-negative tumors showed significantly high alterations even in NACT-treated samples having low CD44 and proliferating cell nuclear antigen expression. Pretherapeutic patients with alterations showed poor prognosis.
CONCLUSION: Alterations of homologous recombination repair pathway genes are needed for the development of BC.

Yun CW, Yun S, Lee JH, et al.
Silencing Prion Protein in HT29 Human Colorectal Cancer Cells Enhances Anticancer Response to Fucoidan.
Anticancer Res. 2016; 36(9):4449-58 [PubMed] Related Publications
BACKGROUND: The putative functions of the cellular prion protein (PrP(c)) are believed to be associated with cell signaling, differentiation, survival, and cancer progression. With respect to cancer development and progression, elevations and mutations of PrP(c) expression have been shown to increase the risk for malignancy and metastasis in breast and colorectal cancer. Since both natural supplements and direct regulation of PrP(c) expression contribute to inhibition of cancer progression and growth, we hypothesized that knockdown of PrP(c) could lead to an enhanced synergic effect on the inhibition of cancer growth by fucoidan.
MATERIALS AND METHODS: PrP(c) expression was suppressed in HT29 human colon cancer cells by utilizing small-interfering RNA (si-PRNP), and cells were subsequently used to study the antiproliferative and anticancer effects of fucoidan treatment of HT29 human colon cancer cells.
RESULTS: Fucoidan treatment significantly inhibited growth and reduced cyclin and cyclin-dependent kinase (CDK) expression in HT29 colon cancer cells. Furthermore, silencing PrP(c) expression with si-PRNP amplified the fucoidan-induced changes in cell proliferation, apoptosis, and migration. Intraperitoneal injection of si-PRNP with fucoidan reduced proliferation and tumor volume in Balb/c nude mice. This enhanced antitumor efficacy was associated with decreased angiogenesis.
CONCLUSION: Combination of fucoidan with silencing of PrP(c) has a synergic effect on the inhibition of HT29 colon cancer cell growth. Furthermore, we provide evidence for the therapeutic application of PrP(c) silencing with other anticancer drugs for cancer.

Ye L, Lin ST, Mi YS, et al.
Overexpression of LARP1 predicts poor prognosis of colorectal cancer and is expected to be a potential therapeutic target.
Tumour Biol. 2016; 37(11):14585-14594 [PubMed] Free Access to Full Article Related Publications
This study investigated the significance of La-related protein 1 (LARP1) in the development and progression of colorectal cancer (CRC). Quantitative real-time polymerase chain reaction and Western blot analyses were carried out to determine the mRNA and protein expression of LARP1 in CRC tumor tissues and paired adjacent normal mucosa. The expression of LARP1 was upregulated in CRC. Immunohistochemical analysis using tissue microarray was performed. A positive correlation between LARP1 and proliferating cell nuclear antigen (PCNA) in the area of proliferation was observed using the Spearman's correlation coefficient test (r = 0.332, P < 0.01). The elevated expression of LARP1 significantly correlated with T stage (P = 0.02), N stage (P = 0.006), M stage (P < 0.001), American Joint Committee on Cancer (AJCC) stage (P = 0.04), differentiation rank (P < 0.001), and PCNA level (P < 0.001). In addition, the inhibitory effect of LARP1 knockdown on CRC cell proliferation was demonstrated using Cell Counting Kit-8 (CCK8) and colony-forming cell (CFC) assays. Multivariate analysis showed that LARP1 was an independent prognostic factor for overall survival (OS; hazard rate (HR) = 0.244; 95 % confidence interval (CI), 0.078-0.769; P = 0.016) and disease-free survival (DFS; HR = 0.281; 95 % CI, 0.086-0.917; P = 0.035) in CRC patients. LARP1 plays an important role in the proliferation of colorectal cancer and represents a new prognostic indicator.

Gao L, Hao J, Niu YY, et al.
Network pharmacology dissection of multiscale mechanisms of herbal medicines in stage IV gastric adenocarcinoma treatment.
Medicine (Baltimore). 2016; 95(35):e4389 [PubMed] Free Access to Full Article Related Publications
Increasing evidence has shown that Chinese Herbal Medicine (CHM) has efficient therapeutic effects for advanced gastric adenocarcinoma, while the therapeutic mechanisms underlying this treatment remain unclear.In this study, the Kaplan-Meier method and Cox regression analysis were used to evaluate the survival benefit of CHM treatment, and correlation analysis was applied to identify the most effective components in the formulas. A network pharmacological approach was developed to decipher the potential therapeutic mechanisms of CHM.CHM treatment was an independent protective factor. The hazard ratio was 0.364 (95% CI 0.245-0.540; P < 0.001). The median survival time was 18 months for patients who received CHM treatment, while for patients without CHM treatment was decreased to 9 months (P < 0.001). Thirteen out of the total 204 herbs were significantly correlated with favorable survival outcomes (P < 0.05), likely representing the most effective components in these formulas. Bioinformatics analyses suggested that the simultaneous manipulation of multiple targets in proliferation pathways (such as epidermal growth factor receptor, fibroblast growth factor receptor 2, human epidermal growth factor receptor 2, proliferating cell nuclear antigen, and insulin like growth factor 2) and the process of cancer metastasis (collagen families, fibronectin 1 and matrix metalloproteinases families) might largely account for the mechanisms of the 13 herbs against gastric adenocarcinoma.A network pharmacology method was introduced to decipher the underlying mechanisms of CHM, which provides a good foundation for herbal research based on clinical data.

Pierscianek D, Wolf S, Keyvani K, et al.
Study of angiogenic signaling pathways in hemangioblastoma.
Neuropathology. 2017; 37(1):3-11 [PubMed] Related Publications
Hemangioblastoma (HB) is mainly located in the brain and the spinal cord. The tumor is composed of two major components, namely neoplastic stromal cells and abundant microvessels. Thus, hyper-vascularization is the hallmark of this tumor. Despite the identification of germline and/or epigenetic mutations of Von Hippel Lindau (VHL) gene as an important pathogenic mechanism of HB, little is known about the molecular signaling involved in this highly vascularized tumor. The present study investigated the key players of multiple angiogenic signaling pathways including VEGF/VEGFR2, EphB4/EphrinB2, SDF1α/CXCR4 and Notch/Dll4 pathways in surgical specimens of 22 HB. The expression of key angiogenic factors was detected by RT(2) -PCR and Western blot. Immunofluorescent staining revealed the cellular localization of these proteins. We demonstrated a massive upregulation of mRNA levels of VEGF and VEGFR2, CXCR4 and SDF1α, EphB4 and EphrinB2, as well as the main components of Dll4-Notch signaling in HB. An increase in the protein expression of VEGF, CXCR4 and the core-components of Dll4-Notch signaling was associated with an activation of Akt and Erk1/2 and accompanied by an elevated expression of PCNA. Immuofluorescent staining revealed the expression of VEGF and CXCR4 in endothelial cells as well as in tumor cells. Dll4 protein was predominantly found in tumor cells, whereas EphB4 immunoreactivity was exclusively detected in endothelial cells. We conclude that multiple key angiogenic pathways were activated in HB, which may synergistically contribute to the abundant vascularization in this tumor. Identification of these aberrant pathways provides potential targets for a possible future application of anti-angiogenic therapy for this tumor, particularly when a total surgical resection becomes difficult due to the localization or multiplicity of the tumor.

Ignarro RS, Facchini G, Vieira AS, et al.
Sulfasalazine intensifies temozolomide cytotoxicity in human glioblastoma cells.
Mol Cell Biochem. 2016; 418(1-2):167-78 [PubMed] Related Publications
Temozolomide (TMZ) is an alkylating agent used to treat glioblastoma. This tumor type synthesizes the antioxidant glutathione through system X c (-) , which is inhibited by sulfasalazine (SAS). We exposed A172 and T98G human glioblastoma cells to a presumably clinically relevant concentration of TMZ (25 µM) and/or 0.5 mM SAS for 1, 3, or 5 days and assessed cell viability. For both cell lines, TMZ alone did not alter viability at any time point, while the coadministration of TMZ and SAS significantly reduced cell viability after 5 days. The drug combination exerted a synergistic effect on A172 cells after 3 and 5 days. Therefore, this particular lineage was subjected to complementary analyses on the genetic (transcriptome) and functional (glutathione and proliferating cell nuclear antigen (PCNA) protein) levels. Cellular pathways containing differentially expressed genes related to the cell cycle were modified by TMZ alone. On the other hand, SAS regulated pathways associated with glutathione metabolism and synthesis, irrespective of TMZ. Moreover, SAS, but not TMZ, depleted the total glutathione level. Compared with the vehicle-treated cells, the level of PCNA protein was lower in cells treated with TMZ alone or in combination with SAS. In conclusion, our data showed that the association of TMZ and SAS is cytotoxic to T98G and A172 cells, thus providing useful insights for improving TMZ clinical efficacy through testing this novel drug combination. Moreover, the present study not only reports original information on differential gene expression in glioblastoma cells exposed to TMZ and/or SAS but also describes an antiproliferative effect of TMZ, which has not yet been observed in A172 cells.

Zhao G, Ge T, Yang X, Li X
The direct anti-cancer efficacy of Sapylin on breast cancer cells in vitro and in vivo.
Hell J Nucl Med. 2016 May-Aug; 19(2):111-7 [PubMed] Related Publications
OBJECTIVE: On the basis of our previous study in which we studied cancer cells under in vitro and in vivo hypoxia conditions, we have now investigated the anti-cancer efficacy of Sapylin on breast cancer cells in mice and human.
MATERIALS AND METHODS: We used different concentrations of Sapylin and the three kinds of breast cancer cells. We used water-soluble tetrazolium salt cell proliferation test (WST-1) to detect changes in cell proliferation and Fluorescein Iothiocyanate-Propidium Iodide (Anexin V FITC-PI) to detect changes in the rate of apoptosis by flow cytometry. We also used reverse transcription-polymerase chain reaction (RT-PCR) to detect possible changes of mRNA expression and used western blot in order to test changes related to protein expression that could lead to cell death. The anti-tumor effect was studied by locally injecting Sapylin into an animal tumor model of breast cancer. We also studied the possible postoperative adverse clinical side effects in 60 female breast cancer patients, stage II-III, aged 25-55 years. The patients underwent a modified, radical operation with smooth incisions which healed well.
RESULTS: Sapylin was able to inhibit by 10%-15% the proliferation of all three kinds of breast cancer cells and also to present positive correlation in vivo with some phenomenona which were time and concentration dependent. After applying Sapylin for 48h, the apoptosis rate was significantly increased by 12%-20%. Apoptosis of breast cancer cells may be related to biological effects supporting cells survival, through B-cell lymphoma gene 2 (Bcl-2nd) Ki67 mRNA expression descent and Bcl-2 associated X Protein (Bax mRNA) expression. This process ultimately promotes cell death. At the same time this process also showed a significant anti-tumor effect (50%-60%) in a mice model. We found no significant adverse reactions, the patients had no significant pain and the postoperative wound was partially healed. After 5 days, the drainage was well reduced and remained so more in the study group than in the control group at a range of 20%-30% (P<0.05).
CONCLUSION: In our research, Sapylin displayed a strong direct anti-cancer effect in breast cancer cells and supported postoperative recovery. Clinically we noticed an obvious reduction of drainage in contrast with the control group.

Nicolas E, Golemis EA, Arora S
POLD1: Central mediator of DNA replication and repair, and implication in cancer and other pathologies.
Gene. 2016; 590(1):128-41 [PubMed] Article available free on PMC after 15/09/2017 Related Publications
The evolutionarily conserved human polymerase delta (POLD1) gene encodes the large p125 subunit which provides the essential catalytic activities of polymerase δ (Polδ), mediated by 5'-3' DNA polymerase and 3'-5' exonuclease moieties. POLD1 associates with three smaller subunits (POLD2, POLD3, POLD4), which together with Replication Factor C and Proliferating Nuclear Cell Antigen constitute the polymerase holoenzyme. Polδ function is essential for replication, with a primary role as the replicase for the lagging strand. Polδ also has an important proofreading ability conferred by the exonuclease activity, which is critical for ensuring replicative fidelity, but also serves to repair DNA lesions arising as a result of exposure to mutagens. Polδ has been shown to be important for multiple forms of DNA repair, including nucleotide excision repair, double strand break repair, base excision repair, and mismatch repair. A growing number of studies in the past decade have linked germline and sporadic mutations in POLD1 and the other subunits of Polδ with human pathologies. Mutations in Polδ in mice and humans lead to genomic instability, mutator phenotype and tumorigenesis. The advent of genome sequencing techniques has identified damaging mutations in the proofreading domain of POLD1 as the underlying cause of some inherited cancers, and suggested that mutations in POLD1 may influence therapeutic management. In addition, mutations in POLD1 have been identified in the developmental disorders of mandibular hypoplasia, deafness, progeroid features and lipodystrophy and atypical Werner syndrome, while changes in expression or activity of POLD1 have been linked to senescence and aging. Intriguingly, some recent evidence suggests that POLD1 function may also be altered in diabetes. We provide an overview of critical Polδ activities in the context of these pathologic conditions.

Sarsik B, Doganavsargil B, Simsir A, et al.
P21 and p27 Immunoexpression in Upper Urinary Tract Urothelial Carcinomas.
Pathol Oncol Res. 2016; 22(4):839-45 [PubMed] Related Publications
p21 and p27 are members of cyclin-dependent kinase family, which function as tumor suppressors and they are involved in development and progression of several malignancies. We investigated their expression in upper urinary tract urothelial carcinoma (UUTUC). Radical nephroureterectomy materials of 34 patients were assessed by immunohistochemistry to evaluate expression of p21 and p27 in UUTUC. Results were correlated with various clinicopathological variables as age, gender, tumor grade and stage, tumor architecture, multifocality, subsequent bladder carcinoma development and clinical outcome.p21 and p27 expression was observed in 52.9 % (n = 18) and 88.2 % (n = 30), respectively. A total of 21 tumors (61.7 %) showed either total loss of p21 expression (n = 16, 47 %) or lower expression (n = 5, 14.7 %). No correlation was found between p21 expression and clinicopathologic variables. Cases showing total loss or lower p27 expression (11.7 % and <25.6 %, respectively) (n = 19, 55.8 %) constituted 67.6 % (n = 23) of the cases totally. This loss or lower p27 expression correlated with a shorter overall survival in both univariate and multivariate analysis (p = 0.039 and p = 0.037, respectively). None of the noninvasive tumors (papillary and nodular tumors) showed loss of p27 (p = 0.016) while 33.3 % of invasive ones showed p27 loss. Noninvasive tumor architecture also correlated with subsequent bladder carcinoma development (p = 0.032) while invasive tumor architecture correlated with advanced stage (T3 and T4) (p = 0.003). p27 is widely expressed in UUTUC, while p21 expression is observed in half of the cases. Loss of p27 expression correlated with tumor architecture and overall survival in UUTUC. However, further research is needed to assess their role in UUTUC.

Calabrese C, Rizzello F, Gionchetti P, et al.
Can supplementation of phytoestrogens/insoluble fibers help the management of duodenal polyps in familial adenomatous polyposis?
Carcinogenesis. 2016; 37(6):600-6 [PubMed] Related Publications
Familial adenomatous polyposis (FAP) is an autosomal dominant inherited disorder, and prophylactic colectomy has been shown to decrease the incidence of colorectal cancer (CRC). Duodenal cancer and desmoids are now the leading causes of death in FAP. We evaluate whether 3 months of oral supplementation with a patented blend of phytoestrogens and indigestible insoluble fibers (ADI) help the management of FAP patients with ileal pouch-anal anastomosis (IPAA). In a prospective open label study, we enrolled 15 FAP patients with IPAA and duodenal polyps who underwent upper gastrointestinal endoscopy at baseline and after 3 months of treatment. The primary endpoint was the change in gene expression in polyp mucosa, whereas the secondary endpoint was the reduction in polyp number and size. After 3 months of ADI treatment, all patients showed a reduction in the number and size of duodenal polyps (P = 0.021). Analysis of the expression of CRC promoting/inhibiting genes in duodenal polyps biopsies demonstrated that different CRC-promoting genes (PCNA, MUC1 and COX-2) were significantly downregulated, whereas CRC-inhibiting genes (ER-β and MUC2) were significantly upregulated after ADI treatment. In conclusion, ADI proved to be safe and effective, and its long-term effects on FAP patients need further investigation. Judging from the results we observed on COX-2 and miR-101 expression, the short-term effects of ADI treatment could be comparable with those obtained using COX-2 inhibitors, with the advantage of being much more tolerable in chronic therapies and void of adverse events.

Zhao Y, Jing Z, Li Y, Mao W
Berberine in combination with cisplatin suppresses breast cancer cell growth through induction of DNA breaks and caspase-3-dependent apoptosis.
Oncol Rep. 2016; 36(1):567-72 [PubMed] Related Publications
Berberine (BBR) is an isoquinoline alkaloid extracted from medicinal plants such as Hydrastis canadensis, Berberis aristata and Coptis chinensis. BBR displays a number of beneficial roles in the treatment of various types of cancers, yet the precise mechanisms of its action remain unclear. Cisplatin is an effective cancer chemotherapeutic agent and functions by generating DNA damage, promoting DNA damage-induced cell cycle arrest and apoptosis; however, its efficacy is challenged by the resistance of tumor cells in clinical application. The aim of the present study was to investigate the effects of BBR in combination with cisplatin on human breast cancer cells. MTT assay showed that BBR inhibited breast cancer MCF-7 cell growth with a 50% inhibitory concentration (IC50) value of 52.178±1.593 µM and the IC50 value of cisplatin was 49.541±1.618 µM, while in combination with 26 µM BBR, the IC50 value of cisplatin was 5.759±0.76 µM. BBR sensitized the MCF-7 cells to cisplatin in a time- and dose-dependent manner. After treatment of BBR and cisplatin, the cellular pro-apoptotic capase-3 and cleaved capspase-3 and caspase-9 were upregulated and the anti-apoptotic Bcl-2 was downregulated. Importantly, BBR restrained the expression of cellular PCNA, and immunofluoresence analysis of γH2AX showed that BBR increased the DNA damages induced by cisplatin. Taken together, the results demonstrated that BBR sensitized MCF-7 cells to cisplatin through induction of DNA breaks and caspase-3-dependent apoptosis.

Xing XK, Wu HY, Chen HL, Feng HG
NDC80 promotes proliferation and metastasis of colon cancer cells.
Genet Mol Res. 2016; 15(2) [PubMed] Related Publications
Chromosome instability is a common feature of tumor cells, and may be an important mechanism in tumor formation. Nuclear division cycle 80 (NDC80) is closely associated with the stability of chromosomes. Therefore, we investigated the relationship between NDC80 and development of colon cancer using a range of methods. Western blotting and immunohistochemistry were employed to determine the expression of this protein in different colon cells and tissues, cell proliferation was measured with an MTT assay, levels of proliferating cell nuclear antigen were examined by immunofluorescence, and cell migration was observed using wound healing tests. Our results showed that the expression of NDC80 in colon cancer cells (CACO2, HCT8, HCT116, and SW480) and tissues (from 20 patients) was higher than that in controls. Moreover, cell proliferation and migration rates were elevated in cells transfected with NDC80 compared to control groups. In summary, NDC80 promotes the proliferation and metastasis of colon cancer cells, and may constitute a new target for gene therapy in treating this disease. Combined with clinicopathological grading, measurement of positive NDC80 expression may be helpful in diagnosing and estimating the prognosis of colon cancer patients.

Sajadian SO, Tripura C, Samani FS, et al.
Vitamin C enhances epigenetic modifications induced by 5-azacytidine and cell cycle arrest in the hepatocellular carcinoma cell lines HLE and Huh7.
Clin Epigenetics. 2016; 8:46 [PubMed] Article available free on PMC after 15/09/2017 Related Publications
BACKGROUND: 5-Azacytidine (5-AZA), a DNA methyl transferase inhibitor, is a clinically used epigenetic drug for cancer therapy. Recently, we have shown that 5-AZA upregulates ten-eleven translocation (TET) protein expression in hepatocellular carcinoma (HCC) cells, which induce active demethylation. Vitamin C facilitates TET activity and enhances active demethylation. The aim of this study is to investigate whether vitamin C is able to enhance the effect of 5-AZA on active demethylation and to evaluate its consequence in HCC cell lines.
METHODS: HCC cell lines (Huh7 and HLE) were treated with 5-AZA and vitamin C. After 48 h of treatment, viability (resazurin conversion), toxicity (lactose dehydrogenase (LDH) release), and proliferation ((proliferating cell nuclear antigen (PCNA)) of single- and combined-treated cells were assessed. The effect of the treatment on 5-hydroxymethylcytosine (5hmC) intensity (immunofluorescence (IF) staining), TET, Snail, GADD45B, and P21 mRNA (real-time PCR) and protein expression (Western blot) were investigated.
RESULTS: Our results indicated that vitamin C enhances the anti-proliferative and apoptotic effect of 5-AZA in HCC cell lines. By further analyzing the events leading to cell cycle arrest, we have shown for the first time in HCC that the combination of 5-AZA and vitamin C leads to an enhanced downregulation of Snail expression, a key transcription factor governing epithelial-mesenchymal transition (EMT) process, and cell cycle arrest.
CONCLUSIONS: We conclude that when combined with 5-AZA, vitamin C enhances TET activity in HCC cells, leading to induction of active demethylation. An increase in P21 expression as a consequence of downregulation of Snail accompanied by the induction of GADD45B expression is the main mechanism leading to cell cycle arrest in HCCs.

Jiao D, Zhang XD
Myricetin suppresses p21-activated kinase 1 in human breast cancer MCF-7 cells through downstream signaling of the β-catenin pathway.
Oncol Rep. 2016; 36(1):342-8 [PubMed] Related Publications
As a main active compound in the bark of waxberry (Myrica rubra), myricetin is a macrocyclic diarylheptanoid, and can trigger the apoptosis of HeLa and PC3 cells. The aim of the present study was to elucidate the anticancer effect of myricetin on human breast cancer MCF-7 cells and to explore the possible mechanisms of action. MCF-7 cells were treated with different concentrations of myricetin (0-80 µM) for 12, 24 and 48 h. In the present study, we found that myricetin suppressed the cell viability of the MCF-7 cells at least partly through the induction of apoptosis as determined by MTT assay and flow cytometry. Western blot analysis revealed that myricetin effectively suppressed the protein expression of p21-activated kinase 1 (PAK1), MEK and phosphorylated extracellular mitogen-activated protein kinase (ERK1/2). In addition, treatment of myricetin activated glycogen synthase kinase-3β (GSK3β) and Bax protein expression, and inhibited β-catenin/cyclin D1/proliferating cell nuclear antigen (PCNA)/survivin and promoted caspase-3 activity in the MCF-7 cells. These results demonstrated that myricetin suppressed the cell viability of human breast cancer MCF-7 cells through PAK1/MEK/ERK/GSK3β/β-catenin/cyclin D1/PCNA/survivin/Bax-caspase-3 signaling.

Hu Z, Lv G, Li Y, et al.
Enhancement of anti-tumor effects of 5-fluorouracil on hepatocellular carcinoma by low-intensity ultrasound.
J Exp Clin Cancer Res. 2016; 35:71 [PubMed] Article available free on PMC after 15/09/2017 Related Publications
BACKGROUND: Hepatocellular carcinoma (HCC) accounts for 75% of liver cancers and is the second most lethal cancer, associated with its multiple etiologies, poor prognosis and resistance to chemotherapy drugs. Chemotherapy treatment on HCC suffers low efficacy of drug uptake and can produce a range of side effects. Here we report an investigation on the effect of a combined treatment on human hepatocellular carcinoma BEL-7402 cells using low-intensity ultrasound (US) and 5-fluorouracil (5-FU).
METHODS: The uptake of 5-FU was measured by the high-performance liquid chromatography (HPLC). DNA damage was detected by the comet assay. MTT assay was used to examine cell viability. Intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (Δψm) were respectively detected by the fluorescent probes DCFH-DA or JC-1. Endogenous apoptosis-associated proteins were analyzed by the western blot and immunohistochemistry. Histopathological changes were evaluated by the hematoxylin and eosin (H&E) staining. Cell apoptosis was evaluated by the TUNEL and flow cytometry assays. Cell proliferation was measured using the immunohistochemical staining of PCNA.
RESULTS: Our results showed that low-intensity US (1.1 MHz, 1.0 W/cm2, 10% duty cycle) significantly enhanced the uptake of 5-FU, 5-FU-mediated DNA damage and reactive oxygen species (ROS) generation. The increased ROS production up-regulated the p53 protein level, which led to the up-regulation of Bax and down-regulation of Bcl-2. The enhancement of ROS generation and the activation of the apoptosis-associated proteins further triggered the collapse of mitochondrial membrane potential, released cytochrome c from mitochondria into cytosol and activated the mitochondria-caspase pathway, and cell apoptosis. Such enhanced effects could be partially blocked by the ROS scavenger N-acetylcysteine (NAC). Overall, low-intensity US combined with 5-FU led to an effective inhibition of tumor growth and prolonged overall survival of BEL-7402 HCC-bearing nude mice by more than 15% compared with 5-FU treatment alone.
CONCLUSIONS: Our results showed that low-intensity ultrasound combined with 5-FU produced much enhanced synergistic anti-tumor effects via enhanced ROS production in treating HCC.

Pan XW, Chen L, Hong Y, et al.
EIF3D silencing suppresses renal cell carcinoma tumorigenesis via inducing G2/M arrest through downregulation of Cyclin B1/CDK1 signaling.
Int J Oncol. 2016; 48(6):2580-90 [PubMed] Related Publications
There are no effective therapies for advanced renal cell carcinoma (RCC), except for VEGFR inhibitors with only ~50% response rate. To identify novel targets and biomarkers for RCC is of great importance in treating RCC. In this study, we observed that eukaryotic initiation factor 3d (EIF3D) expression was significantly increased in RCC compared with paracarcinoma tissue using immunohistochemistry staining and western blot analysis. Furthermore, bioinformatics meta-analysis using ONCOMINE microarray datasets showed that EIF3D mRNA expressions in CCRCC tissue specimens were significantly higher than that in normal tissue specimens. In addition, RCC tissue microarray demonstrated that elevated EIF3D expression was positively correlated with TNM stage and tumor size. EIF3D silencing in human 786-O and ACHN CCRCC cell lines by RNA interference demonstrated that EIF3D knockdown obviously inhibited cell proliferation and colony formation, caused G2/M arrest through downregulation of Cyclin B1 and Cdk1 and upregulation of p21, and induced apoptosis shown by sub-G1 accumulation and RARP cleavage. Moreover, correlation analysis using ONCOMINE microarray datasets indicated that increased EIF3D mRNA expression was positively correlated to PCNA, Cyclin B1 and CDK1 mRNA expression in RCC. Collectively, these results provide reasonable evidences that EIF3D may function as a potential proto-oncogene that participates in the occurrence and progression of RCC.

Hou K, Zhu Z, Wang Y, et al.
Overexpression and Biological Function of Ubiquitin-Specific Protease 42 in Gastric Cancer.
PLoS One. 2016; 11(3):e0152997 [PubMed] Article available free on PMC after 15/09/2017 Related Publications
Ubiquitin-specific protease 42 (USP42) is a member of deubiquitinating enzymes (DUBs). The alterations of DUBs are implicated in the pathogenesis of a wide variety of tumors. However, there are few studies on the expression and biological function of USP42 in gastric cancer (GC). Here, the expression levels of USP42 were significantly higher in GC tissues than in non-tumorous tissues. USP42 expression was significantly correlated with tumor size, TNM stage, lymph node metastasis and overall survival of patients with GC. Moreover, USP42 silencing in two GC cell lines, AGS and MKN-45, notably inhibited cell proliferation, but stimulated G1 phase arrest. The proteins promoting cell cycle progression (Cyclin D1, Cyclin E1 and PCNA) were down-regulated in USP42-suppressed cells. Moreover, inhibition of USP42 in GC cells impaired cell invasion via affecting the expression of matrix metalloproteinases (MMPs) and epithelial-mesenchymal transition (EMT) regulators. In conclusion, USP42 overexpression could be a potential prognostic marker for GC, regulate the survival and invasive properties of GC, and may represent a novel therapeutic molecular target for this tumor.

Cheng S, Zhang X, Huang N, et al.
Down-regulation of S100A9 inhibits osteosarcoma cell growth through inactivating MAPK and NF-κB signaling pathways.
BMC Cancer. 2016; 16:253 [PubMed] Article available free on PMC after 15/09/2017 Related Publications
BACKGROUND: Osteosarcoma (OS) is well-known for poor prognosis due to its high incidence of proliferation and metastasis. Researches have provided valuable insights into the tumorigenesis of S100A9 in some cancers. We aimed to understand the expression level, functions and mechanisms of S100A9 in human osteosarcoma for the first time.
METHODS: The expression of S100A9 protein was detected in 120 human osteosarcoma tissues and 40 normal human bone tissues using tissue microarrays analysis. The knockdown of S100A9 induced by RNA interference (RNAi) method in three osteosarcoma cell lines (U2OS, 143B, MG63) was applied to analyze the effects of S100A9 on cell proliferation, cell cycle distribution, migration, invasion and xenotransplanted tumors. Moreover, MAPK-ERK1/2, MAPK-p38, NF-κB-p65, NF-κB-p50, p21, p27, CDK2 and CDK4 were tested.
RESULTS: The expression of S100A9 was increased in human osteosarcoma issues and was positively correlated with clinical classification and survival rate. Down-regulation of S100A9 inhibited OS cellular proliferation, migration, invasion and cell cycle S phase in vitro and suppressed tumor formation in vivo with the reduction on PCNA and Ki67 proliferation index. Our data also demonstrated that knockdown of S100A9 repressed the protein levels of phospho-ERK1/2, phospho-p50, phospho-p65 except phospho-p38, and prompted up-regulation of p21 and p27 leading to inactivation of cyclin dependent kinase 2(CDK2) and cyclin dependent kinase 4(CDK4).
CONCLUSIONS: S100A9 might be a significant role for predicting osteosarcoma prognosis and down-regulation of S100A9 could be used as a potential target for gene therapy.

Huang JS, Yao CJ, Chuang SE, et al.
Honokiol inhibits sphere formation and xenograft growth of oral cancer side population cells accompanied with JAK/STAT signaling pathway suppression and apoptosis induction.
BMC Cancer. 2016; 16:245 [PubMed] Article available free on PMC after 15/09/2017 Related Publications
BACKGROUND: Eliminating cancer stem cells (CSCs) has been suggested for prevention of tumor recurrence and metastasis. Honokiol, an active compound of Magnolia officinalis, had been proposed to be a potential candidate drug for cancer treatment. We explored its effects on the elimination of oral CSCs both in vitro and in vivo.
METHODS: By using the Hoechst side population (SP) technique, CSCs-like SP cells were isolated from human oral squamous cell carcinoma (OSCC) cell lines, SAS and OECM-1. Effects of honokiol on the apoptosis and signaling pathways of SP-derived spheres were examined by Annexin V/Propidium iodide staining and Western blotting, respectively. The in vivo effectiveness was examined by xenograft mouse model and immunohistochemical tissue staining.
RESULTS: The SP cells possessed higher stemness marker expression (ABCG2, Ep-CAM, Oct-4 and Nestin), clonogenicity, sphere formation capacity as well as tumorigenicity when compared to the parental cells. Treatment of these SP-derived spheres with honokiol resulted in apoptosis induction via Bax/Bcl-2 and caspase-3-dependent pathway. This apoptosis induction was associated with marked suppression of JAK2/STAT3, Akt and Erk signaling pathways in honokiol-treated SAS spheres. Consistent with its effect on JAK2/STAT3 suppression, honokiol also markedly inhibited IL-6-mediated migration of SAS cells. Accordingly, honokiol dose-dependently inhibited the growth of SAS SP xenograft and markedly reduced the immunohistochemical staining of PCNA and endothelial marker CD31 in the xenograft tumor.
CONCLUSIONS: Honokiol suppressed the sphere formation and xenograft growth of oral CSC-like cells in association with apoptosis induction and inhibition of survival/proliferation signaling pathways as well as angiogenesis. These results suggest its potential as an integrative medicine for combating oral cancer through targeting on CSCs.

Boakye CH, Patel K, Doddapaneni R, et al.
Ultra-flexible nanocarriers for enhanced topical delivery of a highly lipophilic antioxidative molecule for skin cancer chemoprevention.
Colloids Surf B Biointerfaces. 2016; 143:156-67 [PubMed] Related Publications
PURPOSE: In this study, we developed cationic ultra-flexible nanocarriers (UltraFLEX-Nano) to surmount the skin barrier structure and to potentiate the topical delivery of a highly lipophilic antioxidative diindolylmethane derivative (DIM-D) for the inhibition of UV-induced DNA damage and skin carcinogenesis.
METHODS: UltraFLEX-Nano was prepared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-3-trimethylammonium-propane, cholesterol and tween-80 by ethanolic injection method; was characterized by Differential Scanning Calorimetric (DSC), Fourier Transform Infrared (FT-IR) and Atomic Force Microscopic (phase-imaging) analyses and permeation studies were performed in dermatomed human skin. The efficacy of DIM-D-UltraFLEX-Nano for skin cancer chemoprevention was evaluated in UVB-induced skin cancer model in vivo.
RESULTS: DIM-D-UltraFLEX-Nano formed a stable mono-dispersion (110.50±0.71nm) with >90% encapsulation of DIM-D that was supported by HPLC, DSC, FT-IR and AFM phase imaging. The blank formulation was non-toxic to human embryonic kidney cells. UltraFLEX-Nano was vastly deformable and highly permeable across the stratum corneum; there was significant (p<0.01) skin deposition of DIM-D for UltraFLEX-Nano that was superior to PEG solution (13.83-fold). DIM-D-UltraFLEX-Nano pretreatment delayed the onset of UVB-induced tumorigenesis (2 weeks) and reduced (p<0.05) the number of tumors observed in SKH-1 mice (3.33-fold), which was comparable to pretreatment with sunscreen (SPF30). Also, DIM-D-UltraFLEX-Nano caused decrease (p<0.05) in UV-induced DNA damage (8-hydroxydeoxyguanosine), skin inflammation (PCNA), epidermal hyperplasia (c-myc, CyclinD1), immunosuppression (IL10), cell survival (AKT), metastasis (Vimentin, MMP-9, TIMP1) but increase in apoptosis (p53 and p21).
CONCLUSION: UltraFLEX-Nano was efficient in enhancing the topical delivery of DIM-D. DIM-D-UltraFLEX-Nano was efficacious in delaying skin tumor incidence and multiplicity in SKH mice comparable to sunscreen (SPF30).

Bai Y, Chen B, Hong W, et al.
Sedum sarmentosum Bunge extract induces apoptosis and inhibits proliferation in pancreatic cancer cells via the hedgehog signaling pathway.
Oncol Rep. 2016; 35(5):2775-84 [PubMed] Related Publications
Sedum sarmentosum Bunge, a traditional Chinese herbal medicine, has a wide range of clinical applications including antibiosis, anti-inflammation and anti-oxidation. In the present study, we identified that its extract (SSBE) exerts pancreatic anticancer activity in vitro and in vivo. In the cultured pancreatic cancer PANC-1 cell line, SSBE inhibited cell growth in a concentration-dependent manner, and it was accompanied by the downregulated expression of proliferating cell nuclear antigen (PCNA). In addition, SSBE treatment also increased cellular apoptosis in a mitochondrial-dependent manner. Moreover, SSBE induced p53 expression, reduced c-Myc expression, and inhibited epithelial-mesenchymal transition (EMT). The antiproliferative activity of SSBE in the pancreatic cancer cells was found to be closely related to cell cycle arrest at the G2/M phase by upregulating p21(Waf1/CIP1) expression. Further study showed that this inhibitory effect of SSBE was through downregulation of the activity of the proliferation-related Hedgehog signaling pathway. Exogenous recombinant protein Shh was used to activate Hedgehog signaling, thereby resulting in the abolishment of the SSBE-mediated inhibition of pancreatic cancer cell growth. In animal xenograft models of pancreatic cancer, activated Hedgehog signaling was also observed compared with the vehicle controls, but was reduced by SSBE administration. As a result, SSBE suppressed the growth of pancreatic tumors. Thus, these findings demonstrate that SSBE has therapeutic potential for pancreatic cancer, and this anticancer effect in pancreatic cancer cells is associated with inhibition of the Hedgehog signaling pathway.

Akrami H, Mahmoodi F, Havasi S, Sharifi A
PlGF knockdown inhibited tumor survival and migration in gastric cancer cell via PI3K/Akt and p38MAPK pathways.
Cell Biochem Funct. 2016; 34(3):173-80 [PubMed] Related Publications
The molecular signalling of placental growth factor (PlGF), a member of the vascular endothelial growth factor family, was not uncovered in human adenocarcinoma gastric cell line (AGS). The purpose of this study was to examine the inhibitory effects of PlGF knockdown on cell proliferation, apoptosis and migration through p38 mitogen-activated protein kinase (p38MAPK) and PI3K pathways in human adenocarcinoma gastric cell line (AGS). To study PlGF knockdown effect, AGS cells were treated with 40 pmol of small interfering RNA (siRNA) related to PlGF gene and also a scrambled siRNA as control. Trypan Blue and Anexin V staining of AGS cells treated with PlGF-specific siRNA showed induction of apoptosis. Wound healing assay and zymography indicated that cellular migration and matrix metalloproteinases activities were reduced in response to PlGF knockdown. Phosphorylation of Akt and p38MAPK was reduced in AGS cells treated with PlGF-specific siRNA. PlGF knockdown decreased transcripts of PI3K, Akt, p38MAPK, PCNA, Caspase-3, OCT3/OCT4 and CD44, but elevated p53 and SOX2 transcripts. Our results indicated that PlGF knockdown decreased migration and induced apoptosis through PI3K/Akt1 and p38MAPK signal transduction in AGS cells.

Guo J, Jing R, Lv X, et al.
H2A/K pseudogene mutation may promote cell proliferation.
Mutat Res. 2016; 787:32-42 [PubMed] Related Publications
Little attention has been paid to the histone H2A/K pseudogene. Results from our laboratory showed that 7 of 10 kidney cancer patients carried a mutant H2A/K pseudogene; therefore, we were interested in determining the relationship between mutant H2A/K and cell proliferation. We used shotgun and label-free proteomics methods to study whether mutant H2A/K lncRNAs affected cell proliferation. Quantitative proteomic analysis indicated that the expression of mutant H2A/K lncRNAs resulted in the upregulation of many oncogenes, which promoted cell proliferation. Further interaction analyses revealed that a proliferating cell nuclear antigen (PCNA)-protein interaction network, with PCNA in the center, contributes to cell proliferation in cells expressing the mutant H2A/K lncRNAs. Western blotting confirmed the critical upregulation of PCNA by mutant H2A/K lncRNA expression. Finally, the promotion of cell proliferation by mutant H2A/K lncRNAs (C290T, C228A and A45G) was confirmed using cell proliferation assays. Although we did not determine the exact mechanism by which the oncogenes were upregulated by the mutant H2A/K lncRNAs, we confirmed that the mutant H2A/K lncRNAs promoted cell proliferation by upregulating PCNA and other oncogenes. The hypothesis that cell proliferation is promoted by the mutant H2A/K lncRNAs was supported by the protein expression and cell proliferation assay results. Therefore, mutant H2A/K lncRNAs may be a new factor in renal carcinogenesis.

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Cite this page: Cotterill SJ. PCNA: Proliferating cell nuclear antigen, Cancer Genetics Web: http://www.cancer-genetics.org/PCNA.htm Accessed:

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