Serine/arginine protein-specific kinase 2 promotes the development and progression of pancreatic cancer by downregulating Numb and p53

Serine/arginine protein-specific kinase 2 (SRPK2) plays a vital role in the progression of a range of different malignancies, including pancreatic cancer. However, the mechanisms are poorly understood. Previous studies have shown that in hepatocellular carcinoma, SRPK2 knockdown leads to the upregulation of the cell fate determining protein Numb, and in pancreatic cancer cells, Numb knockdown prevents ubiquitin-mediated degradation of p53. In this study, we investigated the relationship between SRPK2, Numb and p53 in the development of pancreatic cancer with or without chemical agent treatment in vitro. SRPK2 expression was upregulated in pancreatic cancer tissues and associated with decreased overall survival in pancreatic cancer patients, indicating that expression of this protein can be used as a marker of unfavourable prognosis. Expression of SRPK2 was positively associated with tumour T stage and Union for International Cancer Control (UICC) stage, and negatively associated with Numb expression in serial tissue sections. In pancreatic cancer cells, SRPK2 downregulation or overexpression led to modulation of Numb and wild-type p53 protein expression in response to oxaliplatin treatment. Furthermore, these three endogenous proteins could be coimmunoprecipitated as a triple complex. Numb or p53 knockdown reversed the upregulation of p53 that was induced by silencing SRPK2. SRPK2 overexpression promoted cell invasion and migration, and decreased chemosensitivity of cancer cells to gemcitabine or oxaliplatin treatment. Conversely, SRPK2 silencing decreased cell invasion and migration and increased chemosensitivity; these effects were reversed by silencing p53 in oxaliplatin-treated pancreatic cancer cells. Our data suggest that SRPK2 negatively regulates p53 by downregulating Numb under chemical agent treatment. Thus, SRPK2 promotes the development and progression of pancreatic cancer in a p53-dependent manner.

Prevalence of p53 dysregulations in feline oral squamous cell carcinoma and non-neoplastic oral mucosa

Squamous cell carcinoma is the most common malignant oral tumor in cats. The late presentation is one of the factors contributing to the detrimental prognosis of this disease. The immunohistochemical expression of the p53 tumor suppressor protein has been reported in 24% to 65% of feline oral squamous cell carcinomas, but no study has systematically evaluated in this tumor the presence of p53 encoding gene (TP53) mutations. The aim of this retrospective study was to determine whether p53 immunohistochemistry accurately reflects the mutational status of the TP53 gene in feline oral squamous cell carcinoma. Additionally, the prevalence of p53 dysregulation in feline oral squamous cell carcinoma was compared with that of feline non-neoplastic oral mucosa, in order to investigate the relevance of these dysregulations in cancer development. The association between p53 dysregulations and exposure to environmental tobacco smoke and tumor characteristics was further assessed. Twenty-six incisional biopsies of oral squamous cell carcinomas and 10 cases each of lingual eosinophilic granuloma, chronic gingivostomatitis and normal oral mucosa were included in the study. Eighteen squamous cell carcinomas (69%) expressed p53 and 18 had mutations in exons 5-8 of TP53. The agreement between immunohistochemistry and mutation analysis was 77%. None of non-neoplastic oral mucosa samples had a positive immunohistochemical staining, while one case each of eosinophilic granuloma and chronic gingivostomatitis harbored TP53 mutations. Unlike previously hypothesized, p53 dysregulations were not associated with exposure to environmental tobacco smoke. These results suggest an important role of p53 in feline oral tumorigenesis. Additionally, the immunohistochemical detection of p53 expression appears to reflect the presence of TP53 mutations in the majority of cases. It remains to be determined if the screening for p53 dysregulations, alone or in association with other markers, can eventually contribute to the early detection of this devastating disease.

Expression and Association of Tumor Necrosis Factor Receptor Associated Factor 4 (TRAF4) in Esophageal Squamous Cell Carcinoma

BACKGROUND At present, there is no effective targeted therapy for esophageal squamous cell carcinoma (ESCC), and it is urgent to find new targets for the treatment of ESCC. TRAF4 has been regarded as a cause of carcinogenesis due to overexpression in many cancer types and participation in multiple signaling pathways. However, there are few studies on TRAF4 in ESCC worldwide. Its expression in ESCC and whether it affects the prognosis of patients still remain unclear. MATERIAL AND METHODS We detected the expressions of TRAF4, ki-67, and p53 in 100 cases of ESCC and 80 cases of adjacent normal esophageal squamous epithelium tissues by immunohistochemical technique. We further explored the relationship between TRAF4 and ESCC and its prognosis through statistical analysis. RESULTS TRAF4 was highly expressed in ESCC tissues and was mainly expressed in the cytoplasm. Overexpression of TRAF4 in ESCC was also associated with high expression of ki-67 and p53 (P<0.05). We also found that patients with high expression of TRAF4 had significantly lower OS than in patients with low TRAF4 expression (P<0.05). Overexpression of TRAF4 was an independent risk factor affecting the prognosis of patients (P<0.05). CONCLUSIONS We found that TRAF4 was highly expressed in ESCC tissues and was mainly expressed in the cytoplasm of cancer cells. Overexpression of TRAF4 was an independent risk factor affecting the overall prognosis of patients. The results indicated that TRAF4 may become a new target for the treatment of ESCC in the future.

Toxic and Genotoxic Effects of Silver Nanoparticles in Drosophila

The in vivo model Drosophila melanogaster was used here to determine the detrimental effects induced by silver nanoparticles (AgNPs) exposure. The main aim was to explore its interaction with the intestinal barrier and the genotoxic effects induced in hemocytes. The observed effects were compared with those obtained by silver nitrate, as an agent acting via the release of silver ions. Larvae were fed in food media containing both forms of silver. Results indicated that silver nitrate was more toxic than AgNPs when the viability "egg-to-adult" was determined. Depigmentation was observed in adults including those exposed to nontoxic concentrations, as indicative of exposure action. Interestingly, AgNPs were able to cross the intestinal barrier affecting hemocytes that show significant increases in the levels of intracellular reactive oxygen species. Additionally, significant levels of genotoxic damage, as determined by the comet assay, were also induced. When the expression of different stress-response genes was determined, for both AgNPs and silver nitrate, significant upregulation of Sod2 and p53 genes was observed. Our results confirm for the first time that in an in vivo model as Drosophila, AgNPs are able to cross the intestinal barriers and produce primary DNA damage (comet assay) via oxidative stress induction. In general, the effects induced by silver nitrate were more pronounced than those induced by AgNPs what would emphasize the role of silver ions in the observed effects. Environ. Mol. Mutagen. 60:277-285, 2019. © 2018 Wiley Periodicals, Inc.

Long Interspersed Nuclear Element 1 Retrotransposons Become Deregulated during the Development of Ovarian Cancer Precursor Lesions

There is growing evidence that most high-grade serous ovarian carcinomas likely arise from local dissemination of precursor lesions of the fallopian tube. Evolution of these lesions from early p53 signatures to latter-stage, serous tubal intraepithelial carcinomas (STICs) is characterized by cytologic atypia, accumulation of somatic mutations, and genomic instability, the etiologies of which remain unclear. Long interspersed element 1 (LINE-1) retrotransposon is expressed in many carcinomas, including high-grade serous ovarian carcinoma, where it contributes to genomic instability; however, the timing of LINE-1 activation during this evolution has yet to be elucidated. In this study, we assessed LINE-1 open reading frame 1 protein expression in 12 p53 signature lesions, 32 STICs, and 112 various types of ovarian cancers via immunohistochemical staining and examined LINE-1 promoter methylation in representative cases. We found that 78% and 57% of STICs, with and without concurrent ovarian carcinomas, respectively, exhibited intense LINE-1 immunoreactivity compared with adjacent, normal-appearing fallopian tube epithelium. Hypomethylation of the LINE-1 promoter was found in all STICs exhibiting overexpression. None of the 12 p53 signatures demonstrated significant LINE-1 expression. In ovarian cancer, 84 (75%) of 112 ovarian carcinomas overexpressed LINE-1. Our results indicate that LINE-1 retrotransposons often become deregulated during progression of ovarian cancer precursor lesions from the p53 signature to STIC stages and remain highly expressed in carcinoma.

Nucleostemin expression in breast cancer is a marker of more aggressive phenotype and unfavorable patients' outcome: A STROBE-compliant article

Cancer stem cells (CSCs) are postulated to play significant role in the pathogenesis, progression as well as drug resistance of breast cancer. Nucleostemin (NS) is thought to be a key molecule for stemness, and the clinical impact of NS immunoreactivity in breast cancer can indicate its actual role and future therapeutic potentials.The current study is an observational study with an attempt to evaluate the correlation between NS expression (protein and gene expression levels) and different clinicopathological attributes of invasive breast cancer. For that reason, we investigated NS immunohistochemistry expression on commercial tissue microarray (TMA) of 102 patients and 51 archival specimens from patients admitted to Saqr Hospital, Ras Al Khaimah and diagnosed in Al Baraha Hospital, Dubai, UAE. In addition, the association between NS (GNL3) gene expression and different prognostic parameters as well as patient outcome was also evaluated using 2 large publicly available databases.Interestingly, we found NS expression to be associated with less differentiated and more advance stage. In addition, NS expression was significantly higher in larger size (P = .001) and LN-positive tumors (P = .007). Notably, NS expression was significantly correlated to P53 positive (P = .037) status. Furthermore, NS was found to be more expressed in the highly aggressive breast cancer subtypes including human epidermal growth factor receptor 2 (HER-2) and triple negative breast cancer (TNBC) subtypes. Moreover, our results also showed that high GNL3 gene expression to be associated with poor patient outcome and higher chances of tumor recurrence.Our results highlight NS expression as a marker of aggressive phenotype and poor outcome and indicate its possible use as a potential target for CSC-associated breast cancer management.

VEGF receptor-1 modulates amyloid β 1-42 oligomer-induced senescence in brain endothelial cells

Aggregated amyloid β (Aβ) peptides in the Alzheimer's disease (AD) brain are hypothesized to trigger several downstream pathologies, including cerebrovascular dysfunction. Previous studies have shown that Aβ peptides can have antiangiogenic properties, which may contribute to vascular dysfunction in the early stages of the disease process. We have generated data showing that brain endothelial cells (ECs) exposed to toxic Aβ1-42 oligomers can readily enter a senescence phenotype. To determine the effect of Aβ oligomers on brain ECs, we treated early passaged human brain microvascular ECs and HUVECs with high MW Aβ1-42 oligomers (5 µM, for 72 h). For controls, we used no peptide treatment, 5 µM Aβ1-42 monomers, and 5 µM Aβ1-42 fibrils, respectively. Brain ECs treated with Aβ1-42 oligomers showed increased senescence-associated β-galactosidase staining and increased senescence-associated p21/p53 expression. Treatment with either Aβ1-42 monomer or Aβ1-42 fibrils did not induce senescence in this assay. We then measured vascular endothelial growth factor receptor (VEGFR) expression in the Aβ1-42 oligomer-treated ECs, and these cells showed significantly increased VEGFR-1 expression and decreased VEGFR-2 levels. Overexpression of VEGFR-1 in brain ECs readily induced senescence, suggesting a direct role of VEGFR-1 signaling events in this paradigm. More importantly, small interfering RNA-mediated knockdown of VEGFR-1 expression in brain ECs was able to prevent up-regulation of p21 protein expression and significantly reduced induction of senescence following Aβ1-42 oligomer treatment. Our studies show that exposure to Aβ1-42 oligomers may impair vascular functions by altering VEGFR-1 expression and causing ECs to enter a senescent phenotype. Altered VEGFR expression has been documented in brains of AD patients and suggests that this pathway may play a role in AD disease pathogenesis. These studies suggest that modulating VEGFR-1 expression and signaling events could potentially prevent senescence and rejuvenate EC functions, and provides us with a novel target to pursue for prevention and treatment of cerebrovascular dysfunction in AD.-Angom, R. S., Wang, Y., Wang, E., Pal, K., Bhattacharya, S., Watzlawik, J. O., Rosenberry, T. L., Das, P., Mukhopadhyay, D. VEGF receptor-1 modulates amyloid β 1-42 oligomer-induced senescence in brain endothelial cells.

Attenuation of autophagy flux by 6-shogaol sensitizes human liver cancer cells to TRAIL-induced apoptosis via p53 and ROS

Tumor necrosis factor (TNF)‑related apoptosis‑inducing ligand (TRAIL) is a member of the TNF superfamily and is an antitumor drug that induces apoptosis in tumor cells with minimal or no effects on normal cells. Here, it is demonstrated that 6‑shogaol (6‑sho), a bioactive component of ginger, exerted anti‑inflammatory and anticancer properties, attenuated tumor cell propagation and induced TRAIL‑mediated cell death in liver cancer cells. The current study identified a potential pathway by revealing that TRAIL and 6‑sho or chloroquine acted together to trigger reactive oxygen species (ROS) production, to upregulate tumor‑suppressor protein 53 (p53) expression and to change the mitochondrial transmembrane potential (MTP). Treatment with N‑acetyl‑L‑cysteine reversed these effects, restoring the MTP and attenuated ROS production and p53 expression. Interestingly, treatment with 6‑sho increased p62 and microtubule‑associated proteins 1A/1B light chain 3B‑II levels, indicating an inhibited autophagy flux. In conclusion, attenuation of 6‑sho‑induced autophagy flux sensitized cells to TRAIL‑induced apoptosis via p53 and ROS, suggesting that the administration of TRAIL in combination with 6‑sho may be a suitable therapeutic method for the treatment of TRAIL‑resistant Huh7 liver cells.

Cell Cycle Arrest and Cytotoxic Effects of SAHA and RG7388 Mediated through p21WAF1/CIP1 and p27KIP1 in Cancer Cells

BACKGROUND AND OBJECTIVE

Alterations in gene expressions are often due to epigenetic modifications that can have a significant influence on cancer development, growth, and progression. Lately, histone deacetylase inhibitors (HDACi) such as suberoylanilide hydroxamic acid (SAHA, or vorinostat, MK0683) have been emerging as a new class of drugs with promising therapeutic benefits in controlling cancer growth and metastasis. The small molecule RG7388 (idasanutlin, R05503781) is a newly developed inhibitor that is specific for an oncogene-derived protein called MDM2, which is also in clinical trials for the treatment of various types of cancers. These two drugs have shown the ability to induce p21 expression through distinct mechanisms in MCF-7 and LNCaP cells, which are reported to have wild-type TP53. Our understanding of the molecular mechanism whereby SAHA and RG7388 can induce cell cycle arrest and trigger cell death is still evolving. In this study, we performed experiments to measure the cell cycle arrest effects of SAHA and RG7388 using MCF-7 and LNCaP cells.

MATERIALS AND METHODS

The cytotoxicity, cell cycle arrest, and apoptosis/necroptosis effects of the SAHA and RG7388 treatments were assessed using the Trypan Blue dye exclusion (TBDE) method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescence assay with DEVD-amc substrate, and immunoblotting methods.

RESULTS

The RG7388 treatment was able to induce cell death by elevating p21^WAF1/CIP1 through inhibition of MDM2 in LNCaP, but not in MCF-7 cells, even though there was evidence of p53 elevation. Hence, we suspect that there is some level of uncoupling of p53-mediated transcriptional induction of p21^WAF1/CIP1 in MCF-7 cells.

CONCLUSION

Our results from MCF-7 and LNCaP cells confirmed that SAHA and RG7388 treatments were able to induce cell death via a combination of cell cycle arrest and cytotoxic mechanisms. We speculate that our findings could lead to the development of newer treatments for breast and prostate cancers with drug combinations including HDACi.

Interleukin 6 Knockout Inhibits Aging-Related Accumulation of p53 in the Mouse Myocardium

Interleukin 6 (IL6) and p53 are linked by mutual regulatory mechanisms and are both upregulated in aging. The aim of this study was to evaluate the effects of aging and IL6 on expression of p53 in the mouse heart. Male C57BL6/J wild-type and IL6 knockout mice at the age of 4-5 months (young adult) and 24-30 months (old) were used. Myocardial expression of proteins such as p53, p21, Mdm2, and phospho-Akt/Akt was estimated using Western blotting and expression of p53 and p21 mRNA using real-time polymerase chain reaction. Expression of p53 protein was lower in IL6 knockout hearts than in wild-type hearts. Aging caused significant upregulation of p53 protein level; however, it was significantly higher in old wild-type hearts than in old IL6 knockout hearts (p < .05). Similar p53 mRNA levels in all groups implied IL6 influence on age-related proteasomal degradation of p53. Localization of p53 mainly in the extranuclear compartment and lack of p21 upregulation in aged hearts may suggest quenched transcriptional activity of p53 despite increased abundance of p53. We conclude that lack of IL6 attenuates expression of p53 protein in the hearts of young mice and diminishes its accumulation with aging by post-transcriptional mechanisms; however, this is not related to altered phenotype of aging heart.

Inhibitory effect of Saposhnikovia divaricate polysaccharide on fibroblast-like synoviocytes from rheumatoid arthritis rat in vitro

To study the mechanism and inhibitory effect of Saposhnikovia divaricata polysaccharide (SDP) on fibroblast-like synoviocytes (FLS) isolated from rheumatoid arthritis rat model. Rheumatoid arthritis rat model was established by the classical composite factors including wind, cold, damp plus biological agents. The synovial tissues were digested with trypsin to isolate FLS cells. The different dosage of SDP was applied in culture. The cell viability was evaluated by MTT assay and the apoptosis was determined by analytic flow cytometry. The expression change of p53 gene was monitored by RT-PCR method. The production of secretory inflammation factors TNF-α and IL-1β were determined by ELISA. The proliferative and apoptotic proteins such as Bcl-2, Bax, Caspase-3, MMP-1, MMP-3, P53 were measured by western blotting. Our data demonstrated that treatment with high concentration of SDP could enhance the expression of P53 at both mRNA (P<0.05) and protein (P<0.05) level, inhibit the secretion of TNF-α (P<0.05) and IL-1β (P<0.05). Simultaneously, the Bcl-2/Bax ratio and level of MMP-1, MMP-3 was significantly decreased, and apoptotic marker caspase-3 protein was increased. In addition, the FACS analysis consistently consolidated the apoptosis-inducing effect of SDP on RAFLS. SDP could significantly inhibit dysplasia of RAFLS via modulation of p53 expression and suppression of inflammatory factors, which suggested a potential therapeutic value for rheumatoid arthritis.

Creutzfeldt astrocytes may be seen in IDH-wildtype glioblastoma and retain expression of DNA repair and chromatin binding proteins

Astrocytes with multiple micronuclei ("Creutzfeldt cells") in a brain biopsy are classically associated with demyelinating disease. However, glioblastoma may also have prominent Creutzfeldt astrocytes, along with granular mitoses. Therefore, Creutzfeldt cells may raise the diagnostic dilemma of high-grade glioma vs tumefactive demyelination. While cases of glioblastoma (GBM) with Creutzfeldt astrocytes have been reported, their clinicopathologic spectrum and genetic features are not understood. Studies have proposed that micronuclei in Creutzfeldt cells are a consequence of DNA damage, or may be susceptible to DNA damage and chromothripsis, but their biology in the context of glioblastoma remains unclear. Based on a challenging index case of GBM with mild hypercellularity, Creutzfeldt astrocytes, and granular mitoses on biopsy, we searched our archives for additional cases with similar histopathologic features. We identified 13 cases, reviewed their clinico-radiologic and pathologic features, and examined them for recurrent genetic alterations via NGS (9 cases) and for evidence of DNA damage by immunohistochemistry for DNA repair and chromatin remodeling proteins. We found that Creutzfeldt cell-rich GBMs were IDH-wildtype with no recurring genetic alterations. To test our hypothesis that micronuclei demonstrate loss of DNA repair or chromatin remodeling proteins, we examined the expression of various proteins (MDM2, p53, MLH1, MSH2, PMS2, MSH6, ATRX, INI1, SATB2, Ki67, pHH3) in Creutzfeldt cell rich-GBM. There was intact expression of DNA repair and chromatin remodeling proteins, with accumulation of p53 and reduced MDM2 expression within micronuclei. In contrast, granular mitoses showed pHH3 expression, confirming these cells are undergoing mitotic division, with no accumulation of p53 and reduced expression of DNA repair proteins. Our results emphasize that Creutzfeldt cells are part of the morphologic spectrum of IDH-wildtype glioblastoma. We did not find a role for DNA damage in the generation of Creutzfeldt cells, as both DNA repair and chromatin remodeling protein expression was retained in these cells.

Concomitant p53 and PTEN immunoexpression to predict the risk of malignancy in endometrial polyps

The aim of this retrospective cross-sectional study was to assess the usefulness of phosphase and tensin homolog deleted on chromosome 10 (PTEN) and p53 protein immunoexpression in predicting the risk of malignancy in endometrial polyps. The study was conducted at tertiary public hospital, university teaching center, and private practice clinic.A total of 159 patients with endometrial polyps who underwent hysteroscopic polypectomy between January 2010 to December 2014 were included. p53 and PTEN immunoexpression were assessed in histologic endometrial polyp samples. Patients were allocated into 2 groups: group A, endometrial polyps without atypia (120), and group B, endometrial polyps with atypia (39), which were subdivided into A1 (80) and B1 (21) = p53-/PTEN+ immunostaining; A2 (20) and B2 (11) = p53+/PTEN+; A3 (14) and B3 (4) = p53+/PTEN-; A4 (6) and B4 (3) = p53-/PTEN-.There was no significant difference between groups regarding clinical and epidemiologic parameters, except for age. Neoplasia incidence within groups was higher when at least 1 marker was abnormally stained (in group A, P = .0089, odds ratio [OR] = 13.94 [1.62; 120.27]; in group B, P = .0255, OR 12.73 [1.38; 117.27]). Overall neoplasia incidence was higher in group B than in group A (20.5% vs 5.8%; P = .0113). Malignant neoplasia was found more frequently in patients with p53+ (P = .0006, OR = 7.67 [2.30; 25.54]) and PTEN- (P = .0043; OR = 5.43 [1.77; 16.61]).Immunohistochemical analysis using p53 and PTEN as markers, either alone or concomitantly, can be useful to predict malignant transformation in cases of endometrial polyps.

Association of Parkinson Disease Induction with Cardiac Upregulation of Apoptotic Mediators P53 and Active Caspase-3: An Immunohistochemistry Study

BACKGROUND Apoptosis plays a key role in the pathogenesis of Parkinson disease (PD). Active caspase-3, which is a proapoptotic factor, has been shown to reduce cardiac contractility, causing cardiac dysfunction in many pathological diseases. Reduced cardiac contractility and cardiac autonomic dysfunction have been reported in PD patients and PD mice treated with MPTP. The aim of this study was to show the impact of PD induction on the expression of the apoptotic mediators p53 and active caspase-3 in the heart. MATERIAL AND METHODS Equal control and PD groups were formed by 20 randomly selected normal albino mice. We used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (25 mg/kg) and probenecid (250 mg/kg) (MPTP/p) to induce chronic Parkinsonism in the PD group. Immunohistochemistry was performed to investigate the expression of p53, active caspase-3, and β-adrenergic receptor in hearts from the 2 animal groups. RESULTS P53 and active caspase-3 expression was significantly higher in PD hearts than in the control hearts (p value <0.01). β-adrenergic receptor expression was significantly lower in PD hearts than in control hearts (p value <0.01). CONCLUSIONS Our results show an association of PD with p53 and active caspase-3 overexpression and β-adrenergic receptor underexpression in the heart, potentially promoting the cardiac autonomic dysfunction frequently observed in PD.

Improving adenoviral vectors and strategies for prostate cancer gene therapy

Gene therapy has been evaluated for the treatment of prostate cancer and includes the application of adenoviral vectors encoding a suicide gene or oncolytic adenoviruses that may be armed with a functional transgene. In parallel, versions of adenoviral vector expressing the p53 gene (Ad-p53) have been tested as treatments for head and neck squamous cell carcinoma and non-small cell lung cancer. Although Ad-p53 gene therapy has yielded some interesting results when applied to prostate cancer, it has not been widely explored, perhaps due to current limitations of the approach. To achieve better functionality, improvements in the gene transfer system and the therapeutic regimen may be required. We have developed adenoviral vectors whose transgene expression is controlled by a p53-responsive promoter, which creates a positive feedback mechanism when used to drive the expression of p53. Together with improvements that permit efficient transduction, this new approach was more effective than the use of traditional versions of Ad-p53 in killing prostate cancer cell lines and inhibiting tumor progression. Even so, gene therapy is not expected to replace traditional chemotherapy but should complement the standard of care. In fact, chemotherapy has been shown to assist in viral transduction and transgene expression. The cooperation between gene therapy and chemotherapy is expected to effectively kill tumor cells while permitting the use of reduced chemotherapy drug concentrations and, thus, lowering side effects. Therefore, the combination of gene therapy and chemotherapy may prove essential for the success of both approaches.

Design, synthesis and pharmacological evaluation of new 3-(1H-benzimidazol-2-yl)quinolin-2(1H)-one derivatives as potential antitumor agents

A series of new 3-(1H-benzimidazol-2-yl)quinolin-2(1H)-one derivatives (5a₁-5d₆) were designed and synthesized as antitumor agents. In vitro antitumor assay results showed that some compounds exhibited moderate to high inhibitory activity against HepG2, SK-OV-3, NCI-H460 and BEL-7404 tumor cell lines, and most compounds exhibited much lower cytotoxicity against the HL-7702 normal cell line compared to 5-FU and cisplatin. In vivo antitumor assay results demonstrated that 5a₃ exhibited effective inhibition on tumor growth in the NCI-H460 xenograft mouse model and that 5d₃ displayed excellent antiproliferative activity in the BEL-7402 xenograft model. These results suggested that both 5a₃ and 5d₃ could be used as anticancer drug candidates. Mechanistic studies suggested that compounds 5a₃ and 5d₃ exerted their antitumor activity by up-regulation of Bax, intracellular Ca²⁺ release, ROS generation, downregulation of Bcl-2, activation of caspase-9 and caspase-3 and subsequent cleavage of PARP, inhibition of CDK activity and activation of the p53 protein.

Bardoxolone Methyl Suppresses Hepatitis B Virus Large Surface Protein Variant W4P-Related Carcinogenesis and Hepatocellular Carcinoma Cell Proliferation Via the Inhibition of Signal Transducer and Activator of Transcription 3 Signaling

Bardoxolone methyl (CDDO-me) is a synthetic triterpenoid that has been shown to suppress various cancers and inflammation. It has been implicated for the suppression of signal transducer and activator of transcription 3 (STAT3)-mediated signaling, which plays crucial roles in the development and progression of hepatocellular carcinoma (HCC). Previously, we showed that hepatitis B virus (HBV) large surface protein (LHB) variant W4P promotes carcinogenesis and tumor progression through STAT3 activation. Thus, we examined the anti-cancer activity of CDDO-me against HCC using W4P-LHB-expressing NIH3T3 cells and HepG2 and Huh7 HCC cell lines. CDDO-me exerted cytotoxic activity against W4P-LHB-expressing NIH3T3 cells, HepG2 cells, and Huh7 cells, and induced apoptotic cell death in a dose-dependent manner, demonstrating its anti-cancer activity against HCC. Sublethal concentrations of CDDO-me suppressed STAT3 activation by W4P-LHB ectopic expression and interleukin-6 treatment in W4P-LHB-NIH3T3 and Huh7 cells respectively. The suppression of STAT3 activation by CDDO-me in W4P-LHB-NIH3T3 cells was further confirmed by decreased cyclin D1 protein levels and increased p21 and p53 mRNA synthesis. In addition, CDDO-me treatment resulted in decreased cell migration and colony formation in in vitro assays using W4P-LHB-NIH3T3, HepG2, or Huh7 cell lines, supporting its anti-cancer activity through STAT3 inhibition. Furthermore, -CDDO-me administration significantly suppressed tumor growth induced by W4P-LHB-expressing NIH3T3 cells in nude mice, confirming its anti-cancer activity. Collectively, our findings demonstrated that CDDO-me is capable of suppressing STAT3 activation in HCC cells and cells transformed by the natural variant of HBV protein. The results suggest that CDDO-me can be a potential therapeutic agent against HCC, especially tumors related to HBV mutations.

The characterization of γH2AX and p53 as biomarkers of genotoxic stress in a rainbow trout (Oncorhynchus mykiss) brain cell line

Rainbow trout cell cultures were exposed to three genotoxicants and examined for effects on γH2AX and p53 levels by western blotting and on cell viability using the indicator dyes Alamar Blue (AB) for energy metabolism and 5'-carboxyfluorescein diacetate acetoxymethyl ester (CFDA-AM) for plasma membrane integrity. Bleomycin induced γH2AX and p53 in a dose- and time-dependent manner and had little cytotoxic effect. However, induction was first seen at 0.3 μM for γH2AX but not until 16.5 μM for p53. Methyl methanesulfonate (MMS) increased H2AX phosphorylation but diminished p53 levels as the dose was increased from 908 μM up to 2724 μM. Over this dose range cell viability was progressively lost. 4-nitroquinoline N-oxide (NQO) induced both γH2AX and p53, beginning at 62.5 nM, which was also the concentration at which cell viability began to decline. As the NQO concentration increased further, elevated γH2AX was detected at up to 2.0 μM, while p53 was elevated up to 1.0 μM. Therefore, H2AX phosphorylation was superior to p53 levels as a marker of DNA damage caused by genotoxicants that act by introducing double-stranded DNA breaks (bleomycin), alkyl groups (MMS), and quinoline adducts (NQO).

Expression of p53 Protein in Pterygium

Purpose

The pathogenesis of pterygium is still not completely understood and many environmental factors, including ultraviolet (UV) radiation, play an important role in its etiology. Chronic exposure to UV radiation causes mutations in the p53 tumor suppressor gene, eventually leading to tumor formation. We analyzed the immunohistochemical expression of p53 proteins in pterygial tissues to determine the role of the p53 tumor suppressor gene in the development of pterygium.

Methods

Pterygial specimens were studied immunohistochemically using antibodies against p53 protein.

Results

Out of 38 specimens studied, 35 (92.1%) had conjunctival epithelial cells without p53 specific nuclear staining. Only three specimens (7.9%) had a few p53 stained cells. The role of UV radiation in the pathogenesis of pterygium is supported by epidemiological, geographical and microscopic findings. However, our results are not consistent with these data on a genetic basis.

Conclusions

We conclude that defective p53 tumor suppressor gene function seems to have no role in the pathogenesis of pterygium.

Association of TP53 Mutation, p53 Overexpression, and p53 Codon 72 Polymorphism with Susceptibility to Apoptosis in Adult Patients with Diffuse Astrocytomas

Clarification of TP53 alterations is important to understand the mechanisms underlying the development of diffuse astrocytomas. It has been suggested that the alleles of TP53 at codon 72 differ in their ability to induce apoptosis in human cancers. The aim of this study was to analyze the possible association of TP53 mutation, p53 overexpression, and p53 codon 72 polymorphism with susceptibility to apoptosis in adult Brazilian patients with diffuse astrocytomas. We analyzed 56 surgical specimens of diffuse astrocytomas for alterations of TP53, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) direct sequencing. p53 and cleaved caspase 3 protein expression were assessed by immunohistochemistry. We found TP53 mutations in 19.6% (11 out of 56) of tumors tested, with the lowest mutation rate found in the cases of glioblastomas (8.8%) (p = 0.03). Only 16.1% of tumors tested showed cleaved caspase 3-positive staining, demonstrating that apoptosis is very inhibited in these tumors. All tumors having TP53 mutation and p53 accumulation had no expression of cleaved caspase 3. Additionally, no association was observed in tumors having proline and arginine alleles and expression of cleaved caspase 3. We concluded that clarification of the TP53 alterations allows a better understanding of the mechanisms involved in the progression of diffuse astrocytomas, and the allele status at codon 72 was not associated with apoptosis in these tumors.

p53 Expression in Leukoplakia and Carcinoma of the Tongue

There is growing interest in assessing multistep carcinogenesis and predicting its course using different molecular markers. TP53 is a tumor suppressor gene and appears to be one of the molecular targets of tobacco-related carcinogens in oral cancer. The present study evaluated the role of p53 expression in patients with leukoplakia and carcinoma of the tongue. p53 expression was studied by immunohistochemistry. All patients with leukoplakia of the tongue were male tobacco users. Nuclear staining of p53 was observed in 79% of those patients. Fifty percent, 25% and 4% of the patients expressed 1+, 2+ and 3+ nuclear staining, respectively. When leukoplakia patients were graded according to histopathology, 67% had hyperplasia and 33% had dysplasia. Nuclear p53 accumulation was 88% in hyperplasia and 62% in dysplasia. In patients with tongue cancer, nuclear accumulation of p53 was seen in only 19% of the tumors, with a staining intensity of 1+ in 13%, 2+ in 2% and 3+ in 4% of the tumors. The prevalence of nuclear p53 positivity (79%) was significantly higher in patients with leukoplakia than in patients with tongue cancer (19%; χ2 = 34.32, r = –0.45, df = 1, p = 0.0001; odds ratio (OR) = 16.66, 95% CI, 5.25–52.86). Therefore, leukoplakia patients who show p53 expression have a higher risk of developing tongue cancer than those who do not show p53 expression. As the percentage of positivity of nuclear p53 was very low, none of the clinicopathological parameters or disease status showed any significant association with it. The interesting finding is that none of the female cancer patients showed nuclear p53 expression. Therefore, p53 accumulation is believed to be an early event in neoplastic progression of the tongue.

p53 and HER2/neu Expression in Relation to Chemotherapy Response in Patients with Non-Small Cell Lung Cancer

The aim of the study was to investigate a relation between p53 and HER2/neu expression in resected lung tumors and the response of those tumors to neoadjuvant chemotherapy. The study population included 67 consecutive patients with non-small cell lung cancer (NSCLC) in stage II or III who were operated on at the Institute of Tuberculosis, Warsaw, Poland, between 20 April 2001 and 10 March 2003. All patients received two cycles of chemotherapy consisting of cisplatin and vinorelbine prior to the operation. The response to therapy was assessed as complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD), on the basis of CT scans performed before and after neoadjuvant chemotherapy. p53 and HER2/neu protein expression were evaluated by immunohistochemistry (IHC) using antibodies against p53 (clone PAb 1801, Novocastra) and against HER2/neu (Dako) in paraffin-embedded specimens of tumors. A response to therapy (CR+PR) was observed in 27 patients, while 40 patients (SD+PD) were regarded as resistant to therapy. Resistance was observed significantly more often in tumors above 3 cm in diameter. p53 expression was found in 16 tumors (23.9%) and HER2/neu in 26 tumors (38.8%). We observed a nonsignificant tendency to chemoresistance in tumors with HER-2/neu overexpression and also in tumors with p53 overexpression. If we consider HER-2/neu and p53 together, chemoresistance was observed statistically significantly more often when one or both markers were positive (p<0.05). This significance was independent of tumor size.

Vascular Endothelial Growth Factor (Vegf) and Other Common Tissue Prognostic Indicators in Breast Cancer: A Case-Control Study

VEGF is a specific mitogen and survival factor for endothelial cells and a key promoter of angiogenesis in physiological and pathological conditions. Nevertheless, VEGF tissue evaluation in cancer patients as a prognostic factor compared to the conventional histological and biological parameters is still controversial. In this case-control study, tissue VEGF was retrospectively determined by immunohistochemistry and related to T, N, ER, PgR, c-erbB-2, p53, MIB-1 and cyclin D1 in 129 breast cancer patients. Seventy-four of these patients had developed distant metastases postoperatively. The remaining 55 patients had remained disease-free >10 years after surgery. In 17 (13%) of the 129 patients (six with distant metastases and eleven disease-free) tissue and plasma VEGF were concomitantly evaluated. In univariate analysis no significant differences in VEGF and tumor size were found between metastatic and disease-free patients, whereas there were significant differences in N, ER, PgR, c-erbB-2, p53, MIB-1 and cyclin D1 (p ranging from 0.001 to 0.0001). In multivariate analysis VEGF showed less significance than N, ER, c-erbB-2, MIB-1 and cyclin D1 (p=0.012, p=0.007, p=0.005, p=0.005, p=0.002 and p=0.001, respectively). VEGF was a significant unfavorable prognostic indicator only in the N+ subset (p=0.015), while ER (p=0.05 and p=0.021) and MIB-1 (p=0.031 and p=0.022) were significant in both the N+ and N– subgroups. In multivariate analysis in the 74 metastatic cases VEGF did not show any significance in relation to disease-free interval and overall survival from the time of mastectomy and from the time of relapse, whereas N and PgR did (p ranging from 0.018 to 0.001). In conclusion, tissue VEGF does not seem a suitable candidate to replace conventional histological and other common biological prognostic factors in breast cancer.

DGKζ ablation engenders upregulation of p53 level in the spleen upon whole-body ionizing radiation

The tumor suppressor gene product p53, which coordinates the cellular response to various stresses, is subject to tight regulation by a complex network of signal transduction. The DGK family metabolizes lipidic second messenger diacylglycerol to produce phosphatidic acid. Our earlier studies showed that one isozyme, DGKζ, is involved in the regulatory mechanism of p53. In a cellular model of doxorubicin-induced DNA damage, overexpression of wild-type DGKζ suppresses p53 protein induction and reduces apoptosis, whereas knockdown of DGKζ upregulates p53 protein level and promotes apoptosis. Further examination reveals that DGKζ facilitates p53 degradation via ubiquitin-proteasome system in the cytoplasm. However, it remains undetermined whether the regulatory mechanism of DGKζ on p53 function found in cell-based experiments is also functional at the animal level. This study was conducted to elucidate this point using an experiment with DGKζ-KO mice under DNA damage induced by whole-body ionizing radiation. Our results reveal that p53 protein is induced robustly in the spleen of DGKζ-KO mice upon exposure to ionizing radiation, thereby promoting apoptosis in this organ. Taken together, the results demonstrate that DGKζ plays a sentinel role in p53 expression at the cellular and organismal levels after DNA damaging stress conditions.

Effect of polydatin on expression of p53 and Notch1 in brain tissue of ischemic cerebrovascular disease

Secondary injury of brain tissue following cerebral infarction exhibits a complicated pathogenesis that is attributed to the induction of apoptosis and inflammatory response. The present study aimed to investigate the polydatin neuroprotective effects and their mode of action in cerebral ischemic injury. A total of 80 healthy adult male Sprague-Dawley rats were randomly divided into a Sham operated group, a permanent middle cerebral artery occlusion (MCAO) group, a Polydatin low dose group and a Polydatin high dose group. A total of 20 rats were used in each group. The right MCAO model of rats was established using the modified Longa suture method. The animals in the intervention group were injected intraperitoneally with 12.5mg/kg and/or 50mg/kg of polydatin following infarction. The expression levels of p53 and Notch 1 were measured by immunohistochemical techniques. The degree of left limb hemiplegia in the MCAO group was different compared with that of the low and high dose group of polydatin. The score for the neurological function in the high-dose group of polydatin was lower than that in the MCAO group (High vs MCAO: 2.4±0.31 vs 3.9±0.23, P less than0.05). The results indicated that high dose polydatin could reduce brain edema following cerebral infarction and improve the behavioral score in rats.