Mechanism of As2O3 induces apoptosis of glioma U87 cells

OBJECTIVE

To investigate the mechanism of arsenic trioxide (As2O3)-induced apoptosis of glioma cells.

MATERIALS AND METHODS

U87 cells were treated by different concentrations of As2O3 (8 μmol/L, 6 μmol/L, 4 μmol/L, 2 μmol/L, 1 μmol/L and 0.5 μmol/L) for 24 h, 48 h and 72 h, respectively. Cell viability was detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the appropriate dosage and time were screened. Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) was used to stain cells, followed by an investigation on the apoptosis of cells. In the study of molecular mechanism, the expression of p53 in the cells was determined by immunofluorescence, and then apoptosis-related factors, Fas, FasL and Bax, were tested using Real-time polymerase chain reaction (RT-PCR). Finally, the effect of As2O3 on apoptosis-related proteins, caspase-3 and caspase-9, was investigated by Western blotting.

RESULTS

As2O3 could significantly inhibit proliferation of U87 cells, and the result of TUNEL staining displayed As2O3 had the function of inducing apoptosis. Immunofluorescence results demonstrated that p53 was highly expressed in glioma cells, which was reduced after drug administration. The results of detection of apoptosis factors using RT-PCR revealed that mRNA expressions of Fas, FasL and Bax in the glioma cells were distinctly higher than those in the As2O3 group. The result of Western blotting indicated that caspase-3 and caspase-9 proteins were highly expressed in glioma cells. Analysis of variance showed that the difference between the control group and the As2O3 group was statistically significant (p<0.01).

CONCLUSIONS

As2O3 can inhibit proliferation of glioma cells and induce its apoptosis, which may be correlated with down-regulation of expressions of apoptosis-related factors, Fas, FasL and Bax, and apoptosis-related proteins, p53, caspase-3 and caspase-9.

A comparison of p53 and WT1 immunohistochemical expression patterns in tubo-ovarian high-grade serous carcinoma before and after neoadjuvant chemotherapy

AIMS

The treatment of patients with tubo-ovarian high-grade serous carcinoma (HGSC) is increasingly based on diagnosis on small biopsy samples, and the first surgical sample is often taken post-chemotherapy. p53 and WT1 are important diagnostic markers for HGSC. The effect of neoadjuvant chemotherapy on p53 and WT1 expression has not been widely studied. We aimed to compare p53 and WT1 expression in paired pre-chemotherapy and post-chemotherapy samples of HGSC.

METHODS AND RESULTS

Immunohistochemistry (IHC) was carried out for p53 and WT1 on paired omental HGSC samples pre-chemotherapy and post-chemotherapy. p53 IHC was recorded as normal (wild-type) or abnormal (mutation-type), and was further classified as overexpression, complete absence, or cytoplasmic. WT1 IHC was classified as positive or negative. A subset of cases were further assessed for the extent of nuclear immunoreactivity of WT1 by use of the H-score. Fifty-seven paired samples were stained with p53. Fifty-six of 57 (98%) cases showed mutation-type p53 staining. Pre-chemotherapy and post-chemotherapy IHC results were concordant in 55 of 57 (96%) cases. For WT1, pre-chemotherapy and post-chemotherapy IHC results were concordant in 56 of 58 (97%) cases. In 23 paired WT1 cases, the mean post-treatment H-score decreased from 227 [range 20-298, standard deviation (SD) 64] to 151 (range 0-288, SD 78) (P = 0.0008).

CONCLUSIONS

Immunohistochemical expression of p53 (abnormal/mutation-type pattern) and WT1 in HGSC is almost universal and is largely concordant before and after chemotherapy. This finding underscores the reliability of these diagnostic markers in small samples and in surgical samples following neoadjuvant chemotherapy, with very few exceptions. A novel finding was the significant diminution in intensity of WT1 staining following chemotherapy.

Caveolin-1 in multi drug resistance and two-field lymphadenectomy for thoracic esophageal squamous cell carcinoma

Caveolin-1 plays a very important role in the process of tumor cell transformation. In this paper, we studied the relationship between Cav-1 and other multi drug resistance associated proteins. Moreover, the author compares outcomes according to the extent of lymphadenectomy in patients with upper and middle thoracic esophageal squamous cell carcinoma without clinical cervical metastasis. The short-term and long-term data of 842 consecutive patients who underwent esophagectomy with two-field lymphadenectomy (2FL) or three-field lymphadenectomy (3FL) between February 2005 and July 2013 were retrospectively reviewed. If postoperative infection occurred, according to susceptibility test results, patients were given sensitive antibiotics. The yield of lymph nodes harvested was higher in the 3FL group than in 2FL (P=0.000). There was less blood loss (P =0.000), shorter operative time (P=0.000) less post-operative analgesia needed (P=0.000) and earlier hospital discharge (P =0.000) in 2FL than in 3FL.Overall morbidity was similar in the two groups. However, the rate of major complications was higher after 3FL versus 2FL (P=0.015). There was no 30-day mortality in 2FL and 3FL. The 5-year survival (2FL 35% vs 3FL 38%; P=0.297) and disease-free 5-year survival (2FL 26% vs 3FL 21%; P=0.106) were comparable between the two groups. In univariate analyses, extent of lymphadenectomy was not related to overall 5-year survival. Current results indicated that 2FL may be the preferred lymphadenectomy for upper and middle thoracic esophageal squamous cell carcinoma without clinical cervical metastasis.

DEK proto-oncogene is highly expressed in astrocytic tumors and regulates glioblastoma cell proliferation and apoptosis

Astrocytic tumors are the most common neuroepithelial neoplasms with high relapse rate after surgery. Understanding the molecular mechanisms for astrocytic tumorigenesis and progression will lead to early diagnosis and effective treatment of astrocytic tumors. The DEK mRNA and protein expression in normal brain tissues and astrocytic tumors was quantified. To investigate DEK functions in tumor cells, DEK gene was silenced with siRNA in U251 glioblastoma cells. Cell proliferation, cell cycle and apoptosis were then measured. The expression and activity of key genes that regulate cell proliferation and apoptosis were also measured. We identified DEK as a high expressed gene in astrocytic tumor tissues. DEK expression level was positively correlated with the pathological grade of astrocytic tumors. Gene silencing of DEK in U251 glioblastomas inhibited cell proliferation and blocked cells at G0/G1 phase of cell cycle. DEK depletion also induced cell apoptosis, with up-regulated expression of P53 and P21 and down-regulated expression of Bcl-2 and C-myc. The Caspase-3 activity in U251 cells was also significantly increased after knockdown. Our results provided evidences that DEK regulates proliferation and apoptosis of glioblastomas. DEK gene silencing may induce apoptosis through P53-dependent pathway. Our data indicated DEK plays multiple roles to facilitate tumor growth and maintenance. It can be used as a potential target for astrocytic tumor diagnosis and gene therapy.

Placenta-Specific Protein 1 Expression in Human Papillomavirus 16/18-Positive Cervical Cancers Is Associated With Tumor Histology

OBJECTIVE

Expression of the trophoblast-specific gene placenta-specific protein 1 (PLAC1) has been detected in a wide variety of cancers. However, to date, PLAC1 expression has not been shown in cervical cancer. We have carried out a preliminary study that shows for the first time that PLAC1 is expressed in cervical cancers.

METHODS

A total of 16 primary cervical tumors were obtained from patients shown to be human papillomavirus (HPV) 16/18 positive. Total cellular RNA, genomic DNA, and total protein were purified from each tumor. These materials were then used to determine PLAC1 expression, TP53 mutation status, and p53 expression.

RESULTS

The PLAC1 expression was demonstrated in all 16 primary cervical tumors. The highest levels of expression were found in the more aggressive squamous and adenosquamous histologic types compared with adenocarcinomas. Moreover, the proportion of total PLAC1 message coming from the P1 promoter, also termed the distal or cancer promoter, was significantly greater in the more aggressive squamous and adenosquamous histologic types compared with adenocarcinomas. Finally, in spite of all 16 tumors being HPV-16/18 positive, 3 of 8 squamous cell cancers and 2 of 5 adenocarcinomas expressed wild-type p53 protein. Consistent with the recently shown suppression of the PLAC1P1 promoter by wild-type p53, these p53 positive tumors displayed among the lowest P1-specific PLAC1 expression levels.

CONCLUSIONS

The PLAC1 expression has been demonstrated for the first time in cervical cancers. This preliminary study has further revealed a complex relationship between PLAC1 expression, cervical cancer histologic type, p53, and HPV type that requires further investigation.

Clinical effects of p53 overexpression in squamous cell carcinoma of the sinonasal tract: A systematic meta-analysis with PRISMA guidelines

BACKGROUND

The level of p53 protein expression in sinonasal squamous cell carcinoma (SNSCC) has been estimated, but the results remain inconsistent and the point of consensus has not been reached. This study was first determined to evaluate the clinical effects of p53 expression in SCC of the sinonasal tract.

METHODS

According to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement criteria, the potential literature was searched from diverse databases. The pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated to assess the strength of association between p53 expression and SNSCC.

RESULTS

Final 17 eligible studies were included in a total of 258 cases and 748 controls. The result of p53 expression was shown to be notably higher in SNSCC than in benign sinonasal papillomas and normal sinonasal mucosa (OR = 26.93, P < 0.001; OR = 39.79, P < 0.001; respectively). Subgroup analyses of ethnicity revealed that p53 expression had significant association with SNSCC in Asian and Caucasian populations in cancer versus benign sinonasal papillomas or normal sinonasal mucosa. The expression of p53 was notably higher in moderately or poorly differentiated SNSCC than in well-differentiated SNSCC (OR = 3.51, P = 0.021), while p53 expression was not associated with histological type.

CONCLUSION

The results suggested that p53 overexpression may be correlated with the carcinogenesis and progression of SNSCC. The p53 gene may become a novel drug target of SNSCC. Additional studies on the correlation of p53 expression with clinicopathological features are needed.

Immunohistochemical expression of Ki-67 and p53 along with their digitalized evaluation in the discriminatory analysis of reactive atypia and dysplastic lesions in gastrointestinal biopsies of the stomach

The differential diagnosis between reactive atypia and non-invasive neoplasia (or dysplasia) can be challenging in the case of small conventional forceps biopsy specimens of the stomach. Despite the existence of several classifications for neoplastic epithelial lesions of the stomach, there are few auxiliary tools for aiding in this decision besides standard stains. We studied the utility of Ki-67 and p53 immunohistochemistry in this setting and their clinico-pathological correlations, based on a set of 99 cases with cytological or architectural atypia reviewed by three pathologists. We also tested a digitalized method based on the ImageJ software for the evaluation of Ki-67 expression to determine whether this could be of an additional help.

CONCLUSIONS

Ki-67 and p53 expression correlates well with microscopic and morphological modifications in biopsies and can be a useful tool in confirming or dismissing an impression of dysplasia in routine pathological work-up. Digital processing is cumbersome and of limited value and it could only be of additional help if more automated methods are developed.

Dioscin suppresses hepatocellular carcinoma tumor growth by inducing apoptosis and regulation of TP53, BAX, BCL2 and cleaved CASP3

BACKGROUND

Hepatocellular carcinoma (HCC) is the most commonly diagnosed malignancy of the liver, occurs frequently in the setting of chronic liver injury. Although multiple therapeutic approaches are available, the prognosis of patients with HCC remains poor. Dioscin is a natural steroid saponin that presents in various plants. The anti-cancer and anti-fibrotic effects have been extensively reported. However, the effect of dioscin on HCC remains unclear. We aimed to investigate the anti-HCC properties of dioscin in vitro and in vivo.

METHODS

MTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl-tetrazolium bromide) assay was used to analyze the growth inhibition activity of Dioscin in human cell lines, Bel-7402, HepG2, Lovo, and EAhy926. Antitumor activity through induction of apoptosis was evaluated by flow cytometry using Annexin-V and propidium iodide (PI) staining, laser scanning confocal microscopy (LSCM) analysis with Hochest33342 and PI labeling, and DNA fragmentation analysis. The expression of apoptosis-related proteins tumor protein p53 (TP53), BCL2-associated X protein (BAX), B-Cell CLL/Lymphoma 2 (BCL2) and Caspase 3 (CASP3) was measured by Western blot. Nude mice bearing Bel-7402 were administered intraperitoneally at different doses of dioscin and 5-FU (5-Fluorouracil) treatment was used as a control. Tumor volume and tumor weight of each mouse were then measured.

RESULTS

We demonstrated that Dioscin inhibited proliferation of HCC cell lines in a dose-dependent manner. Dioscin also significantly induced morphological changes during death by apoptosis and increased DNA damage of Bel-7402 cells. Moreover, we demonstrated that Dioscin displayed anticancer activity via up-regulating expression of TP53, BAX and CASP3 protein, as well as down-regulating BCL2 in Bel-7402 cells. Notably, the in vivo anticancer activity of Dioscin was further assessed and achieved greater inhibition efficiency at the concentration increased to 24mg/kg/day than 5-FU at dose of 10mg/kg/day in nude mice bearing Bel-7402 cells.

CONCLUSIONS

Dioscin inhibited tumor growth via inducing apoptosis, which was accompanied by altered expression of apoptotic pathway proteins, such as TP53, BAX, BCL2 and CASP3. Our findings indicate that further evaluation of dioscin as a novel therapeutic approach for HCC is warranted.

Lipotoxic lethal and sublethal stress signaling in hepatocytes: relevance to NASH pathogenesis

The accumulation of lipids is a histologic and biochemical hallmark of obesity-associated nonalcoholic fatty liver disease (NAFLD). A subset of NALFD patients develops progressive liver disease, termed nonalcoholic steatohepatitis, which is characterized by hepatocellular apoptosis and innate immune system-mediated inflammation. These responses are orchestrated by signaling pathways that can be activated by lipids, directly or indirectly. In this review, we discuss palmitate- and lysophosphatidylcholine (LPC)-induced upregulation of p53-upregulated modulator of apoptosis and cell-surface expression of the death receptor TNF-related apoptosis-inducing ligand receptor 2. Next, we review the activation of stress-induced kinases, mixed lineage kinase 3, and c-Jun N-terminal kinase, and the activation of endoplasmic reticulum stress response and its downstream proapoptotic effector, CAAT/enhancer binding homologous protein, by palmitate and LPC. Moreover, the activation of these stress signaling pathways is linked to the release of proinflammatory, proangiogenic, and profibrotic extracellular vesicles by stressed hepatocytes. This review discusses the signaling pathways induced by lethal and sublethal lipid overload that contribute to the pathogenesis of NAFLD.

Immunohistochemical Expression of p53, MDM2, and p21Wafi Oncoproteins in Endometriomas But Not Adenomyosis

OBJECTIVE

p53, MDM2, and p21Waf1 are oncoproteins that regulate the cell cycle. The purpose of this study was to examine the distribution of p53, MDM2, and p21Waf1 oncoprotein expression in endometriomas and in adenomyosis.

METHODS

Tissue samples from 25 women with pathologically confirmed endometriomas and 31 women with pathologically confirmed adenomyosis were analyzed. Expression of p53, MDM2, and p21Waf1 oncoproteins was assessed by immunohistochemical nuclear staining.

RESULTS

p53, MDM2, and p21Waf1 expression were detected in 20%, 60%, and 80% of endometrioma tissue samples, respectively. All endometrioma tissue samples expressing p53 also tested positive for both MDM2 and p21Waf1. MDM2 expression was significantly higher in the proliferative than in the secretory phase of the cycle. In contrast, all 31 adenomyosis tissue samples were negative for p53, MDM2, and p21Waf1 expression.

CONCLUSION

The expression of p53, MDM2, and p21Waf1 suggests a role for these oncoproteins in the regulation of endometrioma cell growth, but not in adenomyosis.

Expression of Cell Cycle-Related Proteins p16, p27, p53 and Ki-67 in HPV-positive and -negative Samples of Papillomas of the Upper Respiratory Tract

BACKGROUND

The role of human papillomavirus (HPV) infection as an etiological factor of respiratory tract papillomas has been described in numerous studies, however its role in malignant transformation has not been clearly defined. Depending on their oncogenic potential they have been classified as low- and high-risk HPVs. We analyzed the expression of four cell cycle-related proteins in order to understand the processes leading to malignant transformation.

MATERIALS AND METHODS

Fifty-six cases of pharyngeal and laryngeal papillomas were analyzed. Nested multiplex polymerase chain reactions to detect the presence of the HPV types, as well as immunohistochemical reactions were performed for the detection of cell cycle-related proteins p16, p27, p53 and Ki-67.

RESULTS

The presence of HPVs 6/11 and 16 was confirmed in 10/56 cases. The expression of all analyzed cell cycle-related proteins was increased in HPV-infected papillomas.

CONCLUSION

HPV infection of the upper respiratory tract may influence the expression of cell cycle-related proteins, that could indicate its possible role in the process of malignant transformation.

Integration of TP53, DREAM, MMB-FOXM1 and RB-E2F target gene analyses identifies cell cycle gene regulatory networks

Cell cycle (CC) and TP53 regulatory networks are frequently deregulated in cancer. While numerous genome-wide studies of TP53 and CC-regulated genes have been performed, significant variation between studies has made it difficult to assess regulation of any given gene of interest. To overcome the limitation of individual studies, we developed a meta-analysis approach to identify high confidence target genes that reflect their frequency of identification in independent datasets. Gene regulatory networks were generated by comparing differential expression of TP53 and CC-regulated genes with chromatin immunoprecipitation studies for TP53, RB1, E2F, DREAM, B-MYB, FOXM1 and MuvB. RNA-seq data from p21-null cells revealed that gene downregulation by TP53 generally requires p21 (CDKN1A). Genes downregulated by TP53 were also identified as CC genes bound by the DREAM complex. The transcription factors RB, E2F1 and E2F7 bind to a subset of DREAM target genes that function in G1/S of the CC while B-MYB, FOXM1 and MuvB control G2/M gene expression. Our approach yields high confidence ranked target gene maps for TP53, DREAM, MMB-FOXM1 and RB-E2F and enables prediction and distinction of CC regulation. A web-based atlas at www.targetgenereg.org enables assessing the regulation of any human gene of interest.

Synthesis of intracellular reduction-sensitive amphiphilic polyethyleneimine and poly(ε-caprolactone) graft copolymer for on-demand release of doxorubicin and p53 plasmid DNA

This study aims to present a new intelligent polymeric nano-system used for combining chemotherapy with non-viral gene therapy against human cancers. An amphiphilic copolymer synthesized through the conjugation of low molecular weight polyethyleneimine (LMw-PEI) and poly(ε-caprolactone) (PCL) via a bio-cleavable disulfide linkage was successfully employed for the simultaneous delivery of drug and gene molecules into target cells. Compared to the conventional PCL copolymerization pathway, this paper represents a straightforward and efficient reaction pathway including the activation of PCL-diol hydroxyl end groups, cystamine attachment and LMw-PEI conjugation which are successfully performed at mild conditions as confirmed by FTIR and (1)H NMR. Thermal, morphological characteristics as well as biocompatibility of the copolymer were investigated. The copolymer showed great tendency to form positively charged nanoparticles (∼163.1nm, +35.3mV) with hydrophobic core and hydrophilic shell compartments implicating its potential for encapsulation of anti-cancer drug and plasmid DNA, respectively. The gel retardation assay confirmed that the nanoparticles could successfully inhibit the migration of pDNA at ∼5 nanoparticle/pDNAw/w. The in vitro cytotoxicity tests and LDH assay revealed that the cationic amphiphilic copolymer was essentially non-toxic in different carcinoma cell lines in contrast to branched PEI 25K. Moreover, the presence of redox sensitive disulfide linkages provided smart nanoparticles with on-demand release behavior in response to reducing agents such as cytoplasmic glutathione (GSH). Importantly, confocal microscopy images revealed that in contrast to free Dox, the nanoparticles were capable of faster internalizing into the cells and accumulating in the perinuclear region or even in the nucleus. Finally, the co-delivery of Dox and p53-pDNA using the copolymer displayed greater cytotoxic effect compared with the Dox-loaded nanoparticle counterpart as revealed by cell viability and Caspase 3 expression assay. These results suggest the copolymer as a promising candidate for the development of smart delivery systems.

STATEMENT OF SIGNIFICANCE

We employed cystamine dihydrochloride as a disulfide linkage for the conjugation of PCL diol and low molecular weight PEI segments through a straightforward and efficient reaction pathway at mild conditions. The new copolymer was essentially non-toxic in different carcinoma cell lines and showed great tendency to form positively charged nanoparticles. Therefore, it can be utilized as a promising platform for simultaneous drug and gene delivery to aggressive cancers. The results of drug and gene co-delivery experiments confirmed the pivotal role of disulfide linkage on the controlled release of both drug and gene molecules in response to glutathione concentration gradient between extracellular and intracellular microenvironments. In addition, the co-delivery of doxorubicin and p53 plasmid DNA using the new copolymer displayed greater cytotoxic effect compared with single agent (i.e. Dox) loaded counterpart, which indicated the significance of rapid dissociation of therapeutic agents from the carrier for synergistic cytotoxic effects on cancer cells.

Aberrant splicing of the DMP1-ARF-MDM2-p53 pathway in cancer

Alternative splicing (AS) of mRNA precursors is a ubiquitous mechanism for generating numerous transcripts with different activities from one genomic locus in mammalian cells. The gene products from a single locus can thus have similar, dominant-negative or even opposing functions. Aberrant AS has been found in cancer to express proteins that promote cell growth, local invasion and metastasis. This review will focus on the aberrant splicing of tumor suppressor/oncogenes that belong to the DMP1-ARF-MDM2-p53 pathway. Our recent study shows that the DMP1 locus generates both tumor-suppressive DMP1α (p53-dependent) and oncogenic DMP1β (p53-independent) splice variants, and the DMP1β/α ratio increases with neoplastic transformation of breast epithelial cells. This process is associated with high DMP1β protein expression and shorter survival of breast cancer (BC) patients. Accumulating pieces of evidence show that ARF is frequently inactivated by aberrant splicing in human cancers, demonstrating its involvement in human malignancies. Splice variants from the MDM2 locus promote cell growth in culture and accelerate tumorigenesis in vivo. Human cancers expressing these splice variants are associated with advanced stage/metastasis, and thus have negative clinical impacts. Although they lack most of the p53-binding domain, their activities are mostly dependent on p53 since they bind to wild-type MDM2. The p53 locus produces splice isoforms that have either favorable (β/γ at the C-terminus) or negative impact (Δ40, Δ133 at the N-terminus) on patients' survival. As the oncogenic AS products from these loci are expressed only in cancer cells, they may eventually become targets for molecular therapies.

Circumscribed sebaceous neoplasms: a morphological, immunohistochemical and molecular analysis

Sebaceous neoplasms encompass a range of lesions, including benign entities such as sebaceous adenoma and sebaceoma, as well as sebaceous carcinoma. The distinction of sebaceous carcinoma from benign lesions relies on histological identification of architectural or cytological features of malignancy. In this study we have assessed the diagnostic discriminatory ability of mitotic rate and immunohistochemical markers (p53, bcl-2 and p16) in a selected group of well circumscribed sebaceous neoplasms, incorporating examples of sebaceous adenoma, sebaceoma and sebaceous carcinoma. We found that mitotic rate was significantly higher in malignant lesions as compared to benign lesions, but none of the immunohistochemical markers showed a discriminatory expression pattern. In addition, we performed a mutational analysis on the same group of lesions using next generation sequencing (NGS) technology. The most commonly mutated gene was TP53, although there was no correlation between the p53 immunohistochemical results and number or type of TP53 mutation detected. CDKN2A, EGFR, CTNNB1 and KRAS were also commonly mutated across all lesions. No particular gene, mutation profile or individual mutation could be identified which directly correlated with the consensus histological diagnosis. In conclusion, within this diagnostically challenging group of lesions, mitotic activity, but not immunohistochemical labelling for p16 or bcl-2, correlates with diagnostic category. While a number of genes potentially involved in the genesis of sebaceous neoplasia were uncovered, any molecular differences between the histological diagnostic categories remain unclear.

Molecular characterization and function of a PTEN gene from Litopenaeus vannamei after Vibrio alginolyticus challenge

PTEN, a tumor suppressor gene, suppresses cell survival, growth, apoptosis, cell migration and DNA damage repair by inhibiting the PI3K/AKT signaling pathway. In this study, the full-length Litopenaeus vannamei PTEN (LvPTEN) cDNA was obtained, containing a 5'UTR of 59bp, an ORF of 1269bp and a 3'UTR of 146bp besides the poly (A) tail. The PTEN gene encoded a protein of 422 amino acids with an estimated molecular mass of 48.3 KDa and a predicted isoelectric point (pI) of 7.6. Subcellular localization analysis revealed that LvPTEN was distributed in both cytoplasm and nucleus, and the tissue distribution patterns showed that LvPTEN was ubiquitously expressed in all the examined tissues. Vibrio alginolyticus challenge induced upregulation of LvPTEN expression. Moreover, RNAi knock-down of LvPTEN in vivo significantly increased the expression of LvAKT mRNA, while reducing that of the downstream apoptosis genes LvP53 and LvCaspase3. LvPTEN knock-down also caused a sharp increase in cumulative mortality, bacterial numbers, and DNA damage in the hemolymph of L. vannamei following V. alginolyticus challenge, together with a sharp decrease in the total hemocyte count (THC). These results suggested that LvPTEN may participate in apoptosis via the PI3K/AKT signaling pathway in L. vannamei, and play an important role in shrimp innate immunity.

Phosphatidylinositol 3-Kinase/AKT Pathway Inhibition by Doxazosin Promotes Glioblastoma Cells Death, Upregulation of p53 and Triggers Low Neurotoxicity

Glioblastoma is the most frequent and malignant brain tumor. Treatment includes chemotherapy with temozolomide concomitant with surgical resection and/or irradiation. However, a number of cases are resistant to temozolomide, as well as the human glioblastoma cell line U138-MG. We investigated doxazosin’s (an antihypertensive drug) activity against glioblastoma cells (C6 and U138-MG) and its neurotoxicity on primary astrocytes and organoptypic hippocampal cultures. For this study, the following methods were used: citotoxicity assays, flow cytometry, western-blotting and confocal microscopy. We showed that doxazosin induces cell death on C6 and U138-MG cells. We observed that doxazosin’s effects on the PI3K/Akt pathway were similar as LY294002 (PI3K specific inhibitor). In glioblastoma cells treated with doxasozin, Akt levels were greatly reduced. Upon examination of activities of proteins downstream of Akt we observed upregulation of GSK-3β and p53. This led to cell proliferation inhibition, cell death induction via caspase-3 activation and cell cycle arrest at G0/G1 phase in glioblastoma cells. We used in this study Lapatinib, a tyrosine kinase inhibitor, as a comparison with doxazosin because they present similar chemical structure. We also tested the neurocitotoxicity of doxazosin in primary astrocytes and organotypic cultures and observed that doxazosin induced cell death on a small percentage of non-tumor cells. Aggressiveness of glioblastoma tumors and dismal prognosis require development of new treatment agents. This includes less toxic drugs, more selective towards tumor cells, causing less damage to the patient. Therefore, our results confirm the potential of doxazosin as an attractive therapeutic antiglioma agent.

Piperlongumine exerts cytotoxic effects against cancer cells with mutant p53 proteins at least in part by restoring the biological functions of the tumor suppressor

Piperlongumine (PL), a small molecule alkaloid present in black pepper (Piper longum), has been reported to kill tumor cells irrespective of their p53 gene status, however, the mechanisms involved are unknown. Since p53 is a redox-sensitive protein, we hypothesized that the redox imbalance induced by PL may affect the structure and/or function of the mutant p53 protein and promote cell death. We used two human colon cancer cell lines, the HT29 and SW620 which harbor the R273H DNA contact abrogatory mutation in p53. PL treatment induced significant ROS production and protein glutathionylation with a concomitant increase in Nrf-2 expression in both cell lines. Surprisingly, immunoprecipitation with wt-p53 specific antibodies (PAb1620) or direct western blotting showed a progressive generation of wild-type-like p53 protein along with a loss of its mutant counterpart in PL-treated HT29 and SW620 cells. Moreover, the EMSA and DNA-affinity blotting revealed a time-dependent restoration of DNA-binding for the mutant p53, which was accompanied by the induction of p53 target genes, MDM2 and Bax. PL, while cytotoxic by itself, also increased the cell killing by many anticancer drugs. In nude mice bearing the HT29 tumors, PL alone (7.5 mg/kg daily) produced a 40% decrease in tumor volume, which was accompanied by diminished intratumoral mutant p53 protein levels. The antitumor efficacy of BCNU or doxorubicin in HT29 xenografts was highly potentiated by PL, followed by expression of apoptotic proteins. These clinically-relevant findings suggest that PL-induced oxidative milieu facilitates a weak functional restoration of mutant p53 through protein glutathionylation and contributes to the increased drug sensitivity.

Mithramycin Depletes Specificity Protein 1 and Activates p53 to Mediate Senescence and Apoptosis of Malignant Pleural Mesothelioma Cells

PURPOSE

Specificity protein 1 (SP1) is an oncogenic transcription factor overexpressed in various human malignancies. This study sought to examine SP1 expression in malignant pleural mesotheliomas (MPM) and ascertain the potential efficacy of targeting SP1 in these neoplasms.

EXPERIMENTAL DESIGN

qRT-PCR, immunoblotting, and immunohistochemical techniques were used to evaluate SP1 expression in cultured MPM cells and MPM specimens and normal mesothelial cells/pleura. MTS, chemotaxis, soft agar, β-galactosidase, and Apo-BrdUrd techniques were used to assess proliferation, migration, clonogenicity, senescence, and apoptosis in MPM cells following SP1 knockdown, p53 overexpression, or mithramycin treatment. Murine subcutaneous and intraperitoneal xenograft models were used to examine effects of mithramycin on MPM growth in vivo. Microarray, qRT-PCR, immunoblotting, and chromatin immunoprecipitation techniques were used to examine gene expression profiles mediated by mithramycin and combined SP1 knockdown/p53 overexpression and correlate these changes with SP1 and p53 levels within target gene promoters.

RESULTS

MPM cells and tumors exhibited higher SP1 mRNA and protein levels relative to control cells/tissues. SP1 knockdown significantly inhibited proliferation, migration, and clonogenicity of MPM cells. Mithramycin depleted SP1 and activated p53, dramatically inhibiting proliferation and clonogenicity of MPM cells. Intraperitoneal mithramycin significantly inhibited growth of subcutaneous MPM xenografts and completely eradicated mesothelioma carcinomatosis in 75% of mice. Mithramycin modulated genes mediating oncogene signaling, cell-cycle regulation, senescence, and apoptosis in vitro and in vivo. The growth-inhibitory effects of mithramycin in MPM cells were recapitulated by combined SP1 knockdown/p53 overexpression.

CONCLUSIONS

These findings provide preclinical rationale for phase II evaluation of mithramycin in patients with mesothelioma.

TRIM59 Promotes the Proliferation and Migration of Non-Small Cell Lung Cancer Cells by Upregulating Cell Cycle Related Proteins

TRIM protein family is an evolutionarily conserved gene family implicated in a number of critical processes including inflammation, immunity, antiviral and cancer. In an effort to profile the expression patterns of TRIM superfamily in several non-small cell lung cancer (NSCLC) cell lines, we found that the expression of 10 TRIM genes including TRIM3, TRIM7, TRIM14, TRIM16, TRIM21, TRIM22, TRIM29, TRIM59, TRIM66 and TRIM70 was significantly upregulated in NSCLC cell lines compared with the normal human bronchial epithelial (HBE) cell line, whereas the expression of 7 other TRIM genes including TRIM4, TRIM9, TRIM36, TRIM46, TRIM54, TRIM67 and TRIM76 was significantly down-regulated in NSCLC cell lines compared with that in HBE cells. As TRIM59 has been reported to act as a proto-oncogene that affects both Ras and RB signal pathways in prostate cancer models, we here focused on the role of TRIM59 in the regulation of NSCLC cell proliferation and migration. We reported that TRIM59 protein was significantly increased in various NSCLC cell lines. SiRNA-induced knocking down of TRIM59 significantly inhibited the proliferation and migration of NSCLC cell lines by arresting cell cycle in G2 phase. Moreover, TRIM59 knocking down affected the expression of a number of cell cycle proteins including CDC25C and CDK1. Finally, we knocked down TRIM59 and found that p53 protein expression levels did not upregulate, so we proposed that TRIM59 may promote NSCLC cell growth through other pathways but not the p53 signaling pathway.

β-Arrestin-1 protects against endoplasmic reticulum stress/p53-upregulated modulator of apoptosis-mediated apoptosis via repressing p-p65/inducible nitric oxide synthase in portal hypertensive gastropathy

Portal hypertensive gastropathy (PHG) is a serious cause of bleeding in patients, and is associated with portal hypertension. β-Arrestins (β-arrestin-1 and β-arrestin-2) are well-established mediators of endocytosis of G-protein-coupled receptors (GPCRs), ubiquitination, and G-protein-independent signaling. The role of β-arrestin-1 (β-arr1) in mucosal apoptosis in PHG remains unclear. The aim of this study was to investigate the involvement of β-arr1 in PHG via its regulation of endoplasmic reticulum (ER) stress/p53-upregulated modulator of apoptosis (PUMA) apoptotic signaling. Gastric mucosal injury and apoptosis were studied in PHG patients and in PHG mouse models. The induction of β-arr1 and the ER stress/PUMA signaling pathway were investigated, and the mechanisms of β-arr1-regulated gastric mucosal apoptosis were analyzed in vivo and in vitro experiments. β-arr1 and ER stress/PUMA signaling elements were markedly induced in the gastric mucosa of PHG patients and mouse models. Blockage of ER stress demonstrably attenuated the mucosal apoptosis of PHG, while targeted deletion of β-arr1 significantly aggravated the injury and ER stress/PUMA-mediated apoptosis. β-arr1 limited the activation of p65 to repress TNF-α-induced inducible nitric oxide synthase (iNOS) expression and NO release, which could regulate ER stress/PUMA-mediated mucosal apoptosis in PHG. In vivo and in vitro experiments further demonstrated that β-arr1 protected against mucosal apoptosis by repressing TNF-α-induced iNOS expression via inhibiting the activation of p65. These results indicated that β-arr1 regulated ER stress/PUMA-induced mucosal epithelial apoptosis through suppression of the TNF-α/p65/iNOS signaling pathway activation and that β-arr1 is a potential therapeutic target for PHG.

The expression of PD-L1 APE1 and P53 in hepatocellular carcinoma and its relationship to clinical pathology

OBJECTIVE

To study the expression of programmed death-ligand1 (PD-L1) in hepatocellular carcinoma and its relationship with clinicopathological characteristics and, prognosis of hepatocellular carcinoma and APE1, P53 protein expression levels.

PATIENTS AND METHODS

A total of 128 patients with hepatocellular carcinoma were enrolled in this study. The expression of PD-L1, APE1 and P53 were detected by immunohistochemistry.Use immunohistochemical ABC staining method to detect the expression levels of PD-L1, APE1 and P53 protein in the hepatocellular carcinoma of 128 cases.

RESULTS

Positive The positive expression rates levels of PD-L1, APE1, and P53 protein in hepatocellular carcinoma tissues are were 82.03%, 92.19%, and 60.94%. PD-L1 positive expression were significantly associated with clinical stage, The PD-L1 protein has a high expression in patients with I ~ II stage liver cancerHBV infection positive and nonportal vein thrombosis (p=0.041; p=0.030; p=0.014). It is inversely correlated with P53 and PD-L1 expression (correlation coefficient -0.227, p=0.010), and positively correlated with APE1 expression (correlation coefficient 0.189, p=0.032). The expression of PD-L1 is associated with the survival time of patients with hepatocellular carcinoma, and the median survival time of patients with high expression of PD-L1 is ten months. The median survival time of patients with low expression is five months (p=0.001). The relationship between the expression of APE1 and P53 protein and overall survival time of patients with hepatocellular carcinoma has not been found.

CONCLUSIONS

The PD-L1 and APE1 expression in hepatocellular carcinoma are related to the level of the expression of P53 protein. The expression state of PD-L1 may be a prognostic factor in hepatocellular carcinoma.

FoxO6 inhibits cell proliferation in lung carcinoma through up-regulation of USP7

Emerging evidence has suggested that misregulation of oncogenes and/or tumor suppressors has a crucial role in the development of lung carcinoma. The present study demonstrated that the expression levels of forkhead box O6 (FOXO6) were downregulated in lung cancer tissue samples, as compared with those in adjacent normal tissue. Overexpression of FOXO6 inhibited the proliferation of A549 human lung cancer cells, whereas knockdown of endogenous FOXO6 expression enhanced cell proliferation. Furthermore, ectopic FOXO6 expression induced the expression of ubiquitin-specific-processing protease 7 (USP7). As a result of this regulation, FOXO6 overexpression led to an elevation of p53 protein expression levels in A549 cells. In conclusion, the results of the present study indicated that the FOXO6/USP7 molecular network has an important role in the regulation of lung cancer development.

Berberine induces apoptosis in human multiple myeloma cell line U266 through hypomethylation of p53 promoter

Berberine has multiple pharmacological activities, such as anti-oxidative, anti-inflammation and anticancer activity. It reduces the proliferation and induces apoptosis in the multiple myeloma cell line, U266. Here we explored the detailed mechanism by analysing the gene expression profiles in U266 treated with or without berberine. DNMT1 andDNMT3B, encoding for a highly conserved member of the DNA methyltransferases, decreased significantly. By dissection of biochemical network database (BNDB) with Kyoto Encyclopaedia of Genes and Genomes (KEGG) annotation, the p53 signalling pathway related genes were altered. By using epigenetic chromatin modification enzymes PCR Array, gene expression microarray, RT-PCR and Bisulphite sequencing, the results show that berberine can repress the expression of DNMT1 and DNMT3B, which triggers hypomethylation of TP53 by changing the DNA methylation level and the alteration of p53 dependent signal pathway in human multiple melanoma cell U266.