P53-related Protein Research Articles

ACAP3 negatively regulated by HDAC2 inhibits the malignant development of papillary thyroid carcinoma cells

ArfGAP with coiled-coil, ankyrin repeat and PH domains 3 (ACAP3) level has been confirmed to be downregulated in papillary thyroid carcinoma (PTC). Histone deacetylase inhibitors (HDACIs) have therapeutic effects on PTC. Accordingly, this study probed into the potential relation of histone deacetylase 2 (HDAC2) and ACAP3 in PTC. Expressions of ACAP3 and HDAC2 in PTC were investigated by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between HDAC2 and ACAP3 was predicted by Pearson analysis. Cell functional assays (cell counting kit-8, transwell, wound healing and flow cytometry assays) and rescue assay were carried out to determine the effects of HDAC2/ACAP3 axis on biological behaviors of PTC cells. Expressions of apoptosis-, epithelial-mesenchymal transition-, Protein Kinase B (AKT)-, and P53-related proteins were measured by Western blot. ACAP3 level was downregulated in PTC tissues and cells. ACAP3 overexpression (oe-ACAP3) suppressed viability, proliferation, migration and invasion of PTC cells, facilitated apoptosis, downregulated the expressions of Protein Kinase B (Bcl-2) and N-cadherin, upregulated the expressions of Bcl-2 associated protein X (Bax) and E-cadherin, diminished the p-AKT/AKT ratio and elevated the p-p53/p53 ratio; however, ACAP3 silencing or HDAC2 overexpression (oe-HDAC2) did the opposite. HDAC2 negatively correlated with ACAP3. The tumor-suppressing effect of oe-ACAP3 in PTC was reversed by oe-HDAC2. Collectively, ACAP3 negatively regulated by HDAC2 suppresses the proliferation and metastasis while facilitating apoptosis of PTC cells.

Synergic effects and possible mechanism of emodin and stilbene glycosides on colorectal cancer

BackgroundPolygonum multiflorum (PM) is a core herb that enhances immunity. It can also detoxify, reduce swelling, and intercept malaria. Its main components, emodin (EMD) and 2,3,5,4'-Tetrahydroxy stilbene-2-O-β-D-glucoside (stilbene glycoside, TSG), have good anti-cancer potential. PurposeThe study aims to investigate synergic effects of EMD and TSG on CRC and its possible mechanism. MethodsNetwork pharmacology and bioinformatics were used to identify targets. HPLC was used to analyze the effective ingredients in PM and to determine the content of the main ingredients. HT-29 cells were used for in vitro experiments. Cell Counting Kit-8 (CCK8) and scratch test were used to detect the effects of various chemical components of PM on the proliferation and migration of HT-29 cells, and Western Bolt (WB) test was used to evaluate the effects of EMD and TSG on P53 pathway. In vivo experiments, the effects of EMD and TSG were evaluated by measuring tumor weight and tumor volume in CRC mice model and histological analysis were carried out with HE staining. The expressions of HSP90, P53, COX2, and ROS were detected by quantitative reverse transcription polymerase chain reaction (PCR), and IL-1β, IL-4, IL-6, IL-10, TGF-β and IFN-γ were detected by enzyme linked immunosorbent assay (ELISA). WB and Immunohistochemistry (IHC) were used to detect the expression of P53 related proteins. ResultsNetwork pharmacology showed PM closely related to colorectal cancer pathway and the core targets included STAT3 and P53; bioinformatics indicated P53 played an important role in the development and prognosis of CRC; chemical analysis showed identified and quantified gallic acid (GA), cis-TSG, trans-TSG, Emodin glucoside(EMDG), physcion glucoside (PHYG), EMD in PM; EMD induced apoptosis and TSG inhibited migration of HT-29 cells; EMD and TSG could coordinately shrink tumor size of CRC mice, elevate expressions of F4/80, decrease the content of IL-6 and TGF-β, promote tumor oxidized and reduce expression of P53 and STAT3 in the tumor. ConclusionsIn vitro experiments showed that TSG inhibited cancer cell migration and EMD induced apoptosis. EMD and TSG had synergic effects on CRC, whose possible mechanism might be to regulate the expression of cytokines and inhibit P53 pathway.

Association and Functional Analysis of Ferroptosis-related Genes with Prostate Hyperplasia

Objective: This study aimed to investigate the association and biological functions of ferroptosis-related genes with prostatic hyperplasia. Methods: Gene information from ferroptosis and prostatic hyperplasia databases was used to screen for ferroptosis-related genes associated with prostate hyperplasia. Protein-protein interaction (PPI), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and enrichment analysis were employed to evaluate the interaction between these genes and prostatic hyperplasia. Results: Through PPI, GO, KEGG, and enrichment analysis, several ferroptosis-related genes associated with prostatic hyperplasia were identified, including phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), mitogen-activated protein kinase 3 (MAPK3), GABA type A receptor associated protein like 1 (GABARAPL1), HRas proto-oncogene (HRAS), tumor suppressor gene p53 (TP53), MAPK1, and autophagy related protein 7 (ATG7). These genes were found to be involved in various biological processes and signaling pathways related to ubiquitin protein ligase binding, protein phosphatase binding, pre-autophagosomal structure, autophagy, the PI3K-Akt signaling pathway and so on. Core genes such as PIK3CA, MAPK3, GABARAPL1, HRAS, TP53, MAPK1, ATG7, EGFR, Kirsten rat sarcoma viral oncogene homolog, and coiled-coil myosin-like BCL2-interacting protein were also found to be associated with transcription factors MYC, ESR2, PML, JUN, and TP53. Protein drug prediction suggested that FTI-277, Ginkgolide A, Tipifarnib, Desvenlafaxine, and Defactinib could potentially target the core genes. Conclusion: This study revealed the association and biological functions of ferroptosis-related genes with prostatic hyperplasia, providing new clues and directions for understanding the pathophysiology of prostatic hyperplasia and selecting therapeutic targets. These findings also contributed to a deeper understanding of the relationship between iron metabolism and prostatic hyperplasia, providing new ideas and methods for the diagnosis and treatment of iron metabolism-related diseases.

KIAA0101 promotes cisplatin resistance through regulating cell apoptosis in lung cancer cells.

Lung cancer is one of the most server mortality in the world and remains a huge threat to human health. Recently, cisplatin-based chemotherapy represented a common therapeutic strategy, however, cisplatin resistance greatly limits the therapy efficacy. We investigated whether KIAA0101 plays a role in cisplatin resistance of lung cancer cells and its mechanisms of action. The expression of KIAA0101 was evaluated based on comprehensive bioinformatic analysis. KIAA0101 knockdown and overexpression A549 cells were constructed to investigate its effects on cell proliferation and apoptosis induced by cisplatin treatment. Western blot analysis was performed to measure the levels of p53-related apoptosis proteins. We found that KIAA0101 was greatly increased in lung cancer tissues and cells. Knockdown of KIAA0101 suppressed cell proliferation and increased cisplatin-induced apoptosis. Knockdown of KIAA0101 also augmented the cisplatin-induced cell apoptosis signaling pathway. Then p53 was found to account for the role of KIAA0101 in cisplatin resistance. In conclusion, our findings provide a novel factor of KIAA0101 in lung cancer resistance, which suggests as a novel target for lung cancer therapy.

Oridonin impedes breast cancer growth by blocking cells in S phase and inhibiting the PI3K/AKT/mTOR signaling pathway

Breast cancer is one of the most common cancers. Oridonin, a traditional Chinese medicine, is believed to inhibit tumor growth, but its particular effects on breast cancer remain unknown. In this study, we examined oridonin's effects on 4T1, MCF-7, and MDAMB-231 cellular activity using CCK8. Scratch assays were used to detect oridonin's effects on cellular migration. Oridonin's effects on the breast cancer cell cycle were studied using flow cytometry, and expression of cell cycle related proteins p53, CDK2, and p21 was detected using Western blot assays. Metabolomics assays were used to detect changes in small molecule metabolites and metabolic pathways in breast cancer cells after treatment with oridonin. Oridonin's effects on breast cancer growth were also studied using xenograft mice. Metabolomics assays were used to detect changes in metabolites and metabolic pathways in xenograft mouse plasma in a control group, model group, and drug administration group. Experimental results showed that oridonin could significantly inhibit breast cancer growth both in vivo and in vitro. Scratch experiments showed that oridonin could inhibit breast cancer cell migration. Oridonin was also able to arrest cells in S phase by affecting several cell cycle-related proteins, including p53, CDK2, and p21. Metabolomic analysis of 4T1 cells identified a total of 33 differential metabolites, including multiple amino acids (such as l-Glutamic acid, l-Asparagine, l-Histidine, l-Valine, and l-Isoleucine). KEGG pathway enrichment analysis showed significant changes in aminoacyl-tRNA biosynthesis, and in multiple amino acid metabolic pathways. Plasma metabolomic analyses of xenograft mice revealed 28 differentially-expressed metabolites between the different animal model groups, including multiple amino acids. KEGG pathway analysis showed significant alterations in multiple amino acid metabolic pathways in oridonin-treated mice. Additionally, changes in the expression of PI3K, AKT and mTOR proteins, as well as in branched amino acids, suggest that oridonin affects the PI3K/AKT/mTOR signaling pathway by inhibiting the biosynthesis of valine, leucine and isoleucine. Taken together, our results suggest that oridonin has strong anti-tumor activity in vitro and in vivo, and has potential as an adjuvant to breast cancer treatment regimens.

Innovative Rocuronium Bromide Topical Formulation for Targeted Skin Drug Delivery: Design, Comprehensive Characterization, In Vitro 2D/3D Human Cell Culture and Permeation.

Cutaneous squamous cell carcinoma (cSCC) is the second-most common type of non-melanoma skin cancer and is linked to long-term exposure to ultraviolet (UV) radiation from the sun. Rocuronium bromide (RocBr) is an FDA-approved drug that targets p53-related protein kinase (PRPK) that inhibits the development of UV-induced cSCC. This study aimed to investigate the physicochemical properties and in vitro behavior of RocBr. Techniques such as thermal analysis, electron microscopy, spectroscopy and in vitro assays were used to characterize RocBr. A topical oil/water emulsion lotion formulation of RocBr was successfully developed and evaluated. The in vitro permeation behavior of RocBr from its lotion formulation was quantified with Strat-M® synthetic biomimetic membrane and EpiDerm™ 3D human skin tissue. Significant membrane retention of RocBr drug was evident and more retention was obtained with the lotion formulation compared with the solution. This is the first systematic and comprehensive study to report these findings.

Upregulation of TMEM40 is associated with the malignant behavior and promotes tumor progression in cervical cancer

ObjectiveRecent studies indicated that transmembrane protein 40 (TMEM40) is associated with several types of cancers but is not clear in cervical cancer (CC). The study aimed to examine the role of TMEM40 in CC and related mechanisms.MethodsThe expression of TMEM40 in CC tissues and cell lines was studied with western blot and real-time quantitative RT-PCR. The effect of TMEM40 on proliferation was evaluated by CCK-8, EdU and colony formation assay. The migration, invasion, cell cycle and apoptosis of CC cells were studied with wound healing, transwell assays and flow cytometry. Tumor growth was evaluated in vivo using a xenogenous subcutaneously implant model.ResultsThe results revealed that the TMEM40 elevation in CC tissues and cell lines was closely correlated with tumor size and lymph node metastasis in clinical patients. Upregulation of TMEM40 with OE-TMEM40 vector promoted the invasion, migration and proliferation, inhibited the apoptosis and led to distinct S cell cycle arrest in CC cell lines. Silencing TMEM40 with shRNA inhibited the invasion, migration and proliferation, promoted apoptosis and led to a G0/G1 cell cycle arrest in CC cell lines. Silence of TMEM40 downregulated the expression of c-MYC, Cyclin D1, matrix metalloproteinase-1 (MMP-1) and matrix metalloproteinase-9 (MMP-9), but in contrast, activated p53 and several apoptosis related proteins such as p53, Caspase-3, Caspase-9 and PARP1. In addition, TMEM40 silencing dramatically decreased tumor growth in mice models.ConclusionThe present study demonstrates that TMEM40 upregulation can be a potential prognostic biomarker and contribute to CC development.

P53 Related Protein Kinase is Required for Arp2/3-Dependent Actin Dynamics of Hemocytes in Drosophila melanogaster.

Cells extend membrane protrusions like lamellipodia and filopodia from the leading edge to sense, to move and to form new contacts. The Arp2/3 complex sustains lamellipodia formation, and in conjunction with the actomyosin contractile system, provides mechanical strength to the cell. Drosophila p53-related protein kinase (Prpk), a Tsc5p ortholog, has been described as essential for cell growth and proliferation. In addition, Prpk interacts with proteins associated to actin filament dynamics such as α-spectrin and the Arp2/3 complex subunit Arpc4. Here, we investigated the role of Prpk in cell shape changes, specifically regarding actin filament dynamics and membrane protrusion formation. We found that reductions in Prpk alter cell shape and the structure of lamellipodia, mimicking the phenotypes evoked by Arp2/3 complex deficiencies. Prpk co-localize and co-immunoprecipitates with the Arp2/3 complex subunit Arpc1 and with the small GTPase Rab35. Importantly, expression of Rab35, known by its ability to recruit upstream regulators of the Arp2/3 complex, could rescue the Prpk knockdown phenotypes. Finally, we evaluated the requirement of Prpk in different developmental contexts, where it was shown to be essential for correct Arp2/3 complex distribution and actin dynamics required for hemocytes migration, recruitment, and phagocytosis during immune response.

Molecular classification of endometrial cancer of Chinese population.

e17623 Background: Endometrial cancer (EC) is one of the most prevalent gynecologic tumors. Current diagnosis and treatment of EC no longer rely solely on traditional histopathological classification. Nevertheless, molecular classification of EC demonstrated clear prognostic value and may guide clinical decision. Methods: In this study, archived tissue specimens from 240 EC patients from Department of Pathology, Peking University People’s Hospital. Four subtypes [POLE ultramutated (POLE mut), microsatellite instability high (MSI-H), copy number low (CNL), and copy number high (CNH)] were stratified by next-generation sequencing (NGS) panel (Amoy Diagnostics, Xiamen, China) targeting POLE, TP53, BRCA1, and BRCA2 genes and microsatellite instability (MSI) status. Immunohistochemistry (IHC) was applied to detect the expression of P53, MMR and other related proteins. Results: Distribution of the EC subtypes in 240 patients was 13 (5.42%) of POLE mut, 36 (15.00%) of MSI-H, 41 (17.08%) of CNH, and 150 (62.50%) of CNL. Compared to published results of EC subtypes in Caucasian including TCGA, ProMisE as well as TransPORTEC, real-world data on Chinese ECs displayed a significantly larger proportion of CNL. In addition, novel biomarkers such as DUSP1, MCF7 and BUB1, which were independent prognostic marker from our previous research were validated. Also, it was found that BRCA2 appeared to be more prevalent in EC than BRCA1. Further analysis revealed that the overall consistency for NGS-based and IHC-based TP53 abnormalities detection and MSI/MMR status assessment were as high as 87.5% and 100%, respectively. Conclusions: Chinese ECs have unique molecular characteristics. In order to perform accurate molecular typing of Chinese ECs, more molecular indicators that match the characteristics of the Chinese population need to be added to the existing classifiers. NGS-based panel is easy to operate and replicate with high accuracy. Thus, it is a viable alternative to IHC in EC molecular classification.

TMT-Based Quantitative Proteomic Analysis Identified Proteins and Signaling Pathways Involved in the Response to Xanthatin Treatment in Human HT-29 Colon Cancer Cells.

Xanthatin is a plant-derived bioactive sesquiterpene lactone from the Xanthium strumarium L., and it has been used as a traditional Chinese medicine. Recently, many studies have reported that xanthatin has anticancer activity. However, a comprehensive understanding of the mechanism underlying the antitumor effects of xanthatin is still lacking. To systematically and comprehensively identify the underlying mechanisms of xanthatin on cancer cells, quantitative proteomic techniques were performed. Xanthatin induced HT-29 colon cancer cells death was detected by lactate dehydrogenase (LDH) release cell death assay. Differentially abundant proteins in two groups (xanthatin treatment groups and control groups) of human HT-29 colon cancer cells were identified using tandem mass tag (TMT) quantitative proteomic techniques. All the significant differentially abundant proteins were generally characterized by performing hierarchical clustering, Gene Ontology (GO) enrichment analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. We chose Western blot analysis to validate the candidate proteins in the proteomics results. A total of 5637 proteins were identified, of which 397 significantly differentially abundant proteins in the groups were quantified. Based on the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses, we found that p53-related signaling played an important role in xanthatin-treated HT-29 colon cancer cells. p53- upregulated modulator of apoptosis (Puma), Sestrin-2 and p14ARF, which were selected from among p53-related signaling proteins, were further validated, and the results were consistent with the tandem mass tag quantitative proteomic results. We first investigated the molecular mechanism underlying the effects of xanthatin treatment on HT-29 colon cancer cells using tandem mass tag quantitative proteomic methods and provided a global comprehensive understanding of the antitumor effects of xanthatin. However, it is necessary to further confirm the function of the differentially abundant proteins and the potentially associated signaling pathways.

TGF-β1 Facilitates TAp63α Protein Lysosomal Degradation to Promote Pancreatic Cancer Cell Migration.

Simple SummaryNumerous studies demonstrate that the activation of transforming growth factor-β (TGF-β) signaling is a critical driving force for promoting cancer cell migration and tumor metastasis. Our recent study indicates that TGF-β1 promotes FBXO3-mediated ΔNp63α protein degradation to facilitate cancer metastasis. In this study, we show that TGF-β1 can inhibit TAp63α protein stability in a lysosome-dependent, but canonical Smad pathway-independent manner, which leads to upregulation of p53-R248W expression, and consequently results in increased pancreatic cancer cell migration.TGF-β signaling plays a pivotal role in promoting tumor cell migration and cancer metastasis. ΔNp63α and TAp63α are two major isoforms of p53-related p63 protein. Our recent study has shown that TGF-β1 promotes ΔNp63α protein degradation to facilitate cancer metastasis. However, whether TAp63α is involved in TGF-β1-induced cancer metastasis remains unclear. In this study, we show that, in human pancreatic cancer MIA PaCa-2 cells harboring p53-R248W allele, TGF-β1 can significantly inhibit TAp63α protein stability in a Smad pathway-independent manner. Lysosome inhibitor, chloroquine, but not proteasome inhibitor MG132, can rescue TGF-β1-induced downregulation of TAp63α protein. In addition, we show that either TGF-β1 treatment or silencing of TAp63α can dramatically increase migration of MIA PaCa-2 cells. Importantly, the restored expression of TAp63α can effectively block TGF-β1-induced migration of MIA PaCa-2 cells. Mechanistically, we show that TGF-β1 promotes TAp63α protein degradation, leading to upregulation of p53-R248W protein expression, and consequently resulting in elevated MIA PaCa-2 cell migration. Together, this study indicates that lysosomal degradation is an important way for regulating TAp63α protein fate and highlights that TGF-β1-TAp63α-mutant p53 axis is critically important in pancreatic cancer metastasis.

Proline oxidase silencing inhibits p53-dependent apoptosis in MCF-7 breast cancer cells

Proline oxidase (POX) is mitochondrial proline-degrading enzyme of dual apoptosis/survival function. POX expression and proline availability are considered an underlying mechanism for differential POX functions. The mechanism for POX-dependent regulation of cell death/survival was studied in wild-type (MCF-7WT) and shRNA POX-silenced breast cancer cells (MCF-7iPOX). Proline concentration and proteomic analyses were determined by LC/MS/QTOF and LC/MS/ORBITRA, respectively. Inhibition of collagen biosynthesis (proline utilizing process) by 2-methoxyestradiol (2ME) contributed to induction of apoptosis in MCF-7WT cells, as detected by increase in the expression of active caspase-3, -9 and p53. The process was not shown in MCF-7iPOX. In MCF-7iPOX cells prolidase activity and expression as well as proline concentration were drastically increased, compared to MCF-7WT cells. Down-regulation of p53 in MCF-7iPOX cells was corroborated by proteomic analysis showing decrease in the expression of p53-related proteins. The mechanism for down-regulation of p53 expression in MCF-7iPOX cells was found at the level of p53–PEPD complex formation that was counteracted by hydrogen peroxide treatment. In this study, we found that silencing POX modulate pro-survival phenotype of MCF-7 cells and suggest that the mechanism of this process undergoes through down-regulation of p53-dependent signaling.

The in vitro ToxTracker and Aneugen Clastogen Evaluation extension assay as a tool in the assessment of relative genotoxic potential of e-liquids and their aerosols.

In vitro (geno)toxicity assessment of electronic vapour products (EVPs), relative to conventional cigarette, currently uses assays, including the micronucleus and Ames tests. Whilst informative on induction of a finite endpoint and relative risk posed by test articles, such assays could benefit from mechanistic supplementation. The ToxTracker and Aneugen Clastogen Evaluation analysis can indicate the activation of reporters associated with (geno)toxicity, including DNA damage, oxidative stress, the p53-related stress response and protein damage. Here, we tested for the different effects of a selection of neat e-liquids, EVP aerosols and Kentucky reference 1R6F cigarette smoke samples in the ToxTracker assay. The assay was initially validated to assess whether a mixture of e-liquid base components, propylene glycol (PG) and vegetable glycerine (VG) had interfering effects within the system. This was achieved by spiking three positive controls into the system with neat PG/VG or phosphate-buffered saline bubbled (bPBS) PG/VG aerosol (nicotine and flavour free). PG/VG did not greatly affect responses induced by the compounds. Next, when compared to cigarette smoke samples, neat e-liquids and bPBS aerosols (tobacco flavour; 1.6% freebase nicotine, 1.6% nicotine salt or 0% nicotine) exhibited reduced and less complex responses. Tested up to a 10% concentration, EVP aerosol bPBS did not induce any ToxTracker reporters. Neat e-liquids, tested up to 1%, induced oxidative stress reporters, thought to be due to their effects on osmolarity in vitro. E-liquid nicotine content did not affect responses induced. Additionally, spiking nicotine alone only induced an oxidative stress response at a supraphysiological level. In conclusion, the ToxTracker assay is a quick, informative screen for genotoxic potential and mechanisms of a variety of (compositionally complex) samples, derived from cigarettes and EVPs. This assay has the potential for future application in the assessment battery for next-generation (smoking alternative) products, including EVPs.

Crystal structure of the human PRPK\u2013TPRKB complex

Mutations of the p53-related protein kinase (PRPK) and TP53RK-binding protein (TPRKB) cause Galloway-Mowat syndrome (GAMOS) and are found in various human cancers. We have previously shown that small compounds targeting PRPK showed anti-cancer activity against colon and skin cancer. Here we present the 2.53 Å crystal structure of the human PRPK-TPRKB-AMPPNP (adenylyl-imidodiphosphate) complex. The structure reveals details in PRPK-AMPPNP coordination and PRPK-TPRKB interaction. PRPK appears in an active conformation, albeit lacking the conventional kinase activation loop. We constructed a structural model of the human EKC/KEOPS complex, composed of PRPK, TPRKB, OSGEP, LAGE3, and GON7. Disease mutations in PRPK and TPRKB are mapped into the structure, and we show that one mutation, PRPK K238Nfs*2, lost the binding to OSGEP. Our structure also makes the virtual screening possible and paves the way for more rational drug design.

Single Cell Detection of the p53 Protein by Mass Cytometry.

Simple SummaryInvestigation of protein expression in cancer cells is an important part of the diagnostic process. Increasing knowledge about expression of different proteins has been exploited for prognostic assessments and in some cases also for selection of treatment. The p53 protein has proven important in development of various cancers, and the expression of this protein and its signaling pathway is therefore of interest when examining cancer patient samples. Here, we present mass cytometry as a tool for detection of p53 expression. Mass cytometry allows for measurement of up to 50 parameters per sample with single cell resolution, and we aim to demonstrate its potential for p53-focused research.Purpose: The p53 protein and its post-translational modifications are distinctly expressed in various normal cell types and malignant cells and are usually detected by immunohistochemistry and flow cytometry in contemporary diagnostics. Here, we describe an approach for simultaneous multiparameter detection of p53, its post-translational modifications and p53 pathway-related signaling proteins in single cells using mass cytometry. Method: We conjugated p53-specific antibodies to metal tags for detection by mass cytometry, allowing the detection of proteins and their post-translational modifications in single cells. We provide an overview of the antibody validation process using relevant biological controls, including cell lines treated in vitro with a stimulus (irradiation) known to induce changes in the expression level of p53. Finally, we present the potential of the method through investigation of primary samples from leukemia patients with distinct TP53 mutational status. Results: The p53 protein can be detected in cell lines and in primary samples by mass cytometry. By combining antibodies for p53-related signaling proteins with a surface marker panel, we show that mass cytometry can be used to decipher the single cell p53 signaling pathway in heterogeneous patient samples. Conclusion: Single cell profiling by mass cytometry allows the investigation of the p53 functionality through examination of relevant downstream signaling proteins in normal and malignant cells. Our work illustrates a novel approach for single cell profiling of p53.

A212 CHROMOFUNGIN PROTECTS AGAINST DSS-INDUCED COLITIS BY REGULATING P-53 APOPTITIC PATHWAY

Abstract Background Development of ulcerative colitis is associated with epithelial apoptosis mediated by p53-apoptotic pathway through the activation B-cell lymphoma 2 (Bcl-2), Bcl-2 associated-X protein (BAX) and Bcl-2 antagonist/killer-1 (BAK1) proteins. Chromofungin (CHR), a chromogranin-A derived peptide expressing a cell penetrating peptide motif, decreased the severity of colitis via the suppression of mucosal and pro-inflammatory macrophages-related p53-dependent apoptosis. Aims We aimed to investigate a) whether the gene profile expression of apoptosis could be extended to other p53-associated genes; b) whether the gene expression of some of the p53-apoptosis marker could be confirmed by protein analysis; and c) whether due to the cell penetrating peptide motif, CHR could enter into peritoneal macrophages. Methods UC-related colitis was induced in C57BL/6 mice (7 weeks) by administering dextran sulfate sodium (DSS) (5%, 5 days). Preventive CHR (2.5 mg/kg/day) or vehicle treatment started 1-day before colitis induction and lasted for 5-days. Profiler™ PCR Array was performed to screen a panel of 84 genes representative of the p53 signal pathway in colitic whole mucosa distal colonic samples treated or not with CHR. Western blot analysis was performed to confirm individual protein changes. Naïve macrophages were plated overnight and nonadherent cells were removed the next day. Cells were incubated with rhodamined CHR (4 ul) for 5, 10, 20, 30 min before washing and fixing them, detection was made via confocal microscopy. Results In colitic conditions, an up regulation of 26 genes associated to the p53-dependent apoptosis pathway were detected including Apaf1, Bax, Bbc3, Bcl2, Cradd, Fadd, Cul9, Pmaip1, Tnfrsf10b. In vivo CHR treatment decreased significantly the colitis and was associated with a significant downregulation of 19 genes including the 9 aforementioned when compared with biopsies from colitic groups. Compared to untreated groups, colitic mice treated with CHR demonstrated a significant decrease of BAX and BAK protein and the apoptotic ER stress inducer marker, X-Binding Protein 1. A large number of peritoneal macrophages displayed rhodamine within the all intracellular compartment. The presence of the peptide inside the cell can be visible as early as 5 min and the signal gradually increases. Conclusions CHR decreases the inflammatory process via the suppression of a large number of p53-related apoptotic proteins. CHR quickly enters the macrophage but the exact mechanism of entrance needs to be further defined. Targeting functional analysis of CHR may lead in the future to novel therapeutics for UC. Funding Agencies CCCNSERC

ROS-Dependent Cell Death Induced by Parthenolide in Human Hepatoma Cell HepG2

With the increase of the action time and dosing concentration, the proliferation of HepG2 cell was inhibited and its vitality gradually decreased. FCM showed that, with the increase of PN action time, the MMP gradually decreased; calcium ions flowed inwards; the cell cycle was arrested in phase G1; the cell apoptosis rate, especially late apoptosis and necrotic cells, increased. The shear expression of apoptosis-related proteins caspase3 and caspase9 was up-regulated; the shear expression of AIF, MIF and PARP1 proteins associated with Caspase-independent apoptosis, i.e. Parthanatos apoptosis, showed time-dependent up-regulation; the long and short expressions of anti-apoptosis protein FLIP showed different degrees of decrease; the ex-pression of autophagy-related proteins LC3A/B and becin-1 was up-regulated; the expression of P62 protein was down-regulated; the expression of cycle- related proteins P53, P27 and P21 increased significantly; the expression of CyclinD1 and CyclinE1 decreased. FCM was used to detect the increase of ROS with the action time of PN; and its generation level showed an increasing trend; after the combination with ROS scavenger NAC, there was no significant difference in cell viability with the control group. There was no significant difference in the expression level of relevant cell death protein with DMSO control group. There was no difference in intracellular ROS generation level with the control group. Conclusion: PN induces the ROS generation in HepG2 cell, blocks its cycle and causes apoptosis and au-tophagy to play an anti-tumor effect.

Ellagic Acid Enhances the Antitumor Efficacy of Bevacizumab in an In Vitro Glioblastoma Model

The anticarcinogenic effect of ellagic acid (EA), a natural phenol of fruits and vegetables, has been investigated in several types of tumors. The combined effect of EA with bevacizumab (BEV), a common drug used in treatment of recurrent glioma, on glioblastoma has not been reported. This study observed the combined effect of EA with BEV on the expression profile of the C6 glioma cell line. Rat C6 glioma cells were treated with EA at 100 μmol/L concentration in combination with BEV at 100 ng/mL concentration for 24, 48, and 72 hours. Cell proliferation was detected by 5-bromo-2'-deoxyuridine immunohistochemistry, and p53 and caspase-3 protein levels were determined by immunohistochemistry and assessed by the H-Score. Expression profiles for P-glycoprotein (MDR1), O6-methylguanine DNA methyltransferase (MGMT), caspase-3, and p53 related proteins were detected by reverse transcriptase polymerase chain reaction after EA treatment with or without BEV. EA combined with BEV conspicuously reduced the cell viability of C6 glioma cells for all incubation times. EA significantly downregulated expression of MGMT regardless of combination with BEV even in the early hours after treatment. Combined EA and BEV reduced MDR1 expression only at 72 hours. EA affected the apoptotic proteins of p53 and caspase-3 at protein level in a time-dependent manner, but not at gene level. This study suggests successful antiproliferative efficacy of EA combined with BEV, probably through inhibition of MGMT expression and time-dependent inhibition of MDR1. EA combined with BEV may be an alternative treatment for drug-resistant gliomas.

Abstract 1113: Targeting PRPK function blocks colon cancer metastasis

Abstract The biological functions of the p53-related protein kinase (PRPK) remain unclear. We have previously demonstrated that PRPK is phosphorylated by the T-LAK cell-originated protein kinase (TOPK) and that phosphorylated PRPK (p-PRPK) promotes colon cancer metastasis. Here, we analyzed colon adenocarcinomas from 87 patients and found that higher expression levels of p-PRPK were associated with later stages of metastatic dissemination (stage III and IV) as compared with earlier stages (stages I and II). Indeed, levels of p-PRPK were higher in metastatic versus malignant human colon adenocarcinomas. Knocking down PRPK expression attenuated colorectal liver and lung metastasis of colon cancer cells in vivo. An in vitro kinase assay indicated that active PRPK does not phosphorylate p53 directly. We found that PRPK phosphorylates survivin, a regulator of colon cancer metastasis. PRPK phosphorylates survivin at Thr34, which is important for survivin stability. Taken together, our data strongly suggest that the PRPK signaling pathway promotes colon cancer metastasis by modulating survivin stability, and that PRPK could be a new prognostic marker for the survival of colon cancer patients. In addition, we identified an FDA-approved bacteriostatic antibiotic, fusidic acid sodium salt (fusidic acid or FA) as an inhibitor of PRPK, and show that FA combined with 5-fluorouracil (5-FU) inhibited PRPK activity and colon cancer metastasis to the lung in mice. We contend that the combination of FA with 5-FU could be an alternative therapeutic strategy to traditional chemotherapy for colon cancer patients with poor prognosis. Citation Format: Tatyana Zykova, Ke Yao, Seung Ho Shin, Eunmiri Roh, Weiya Ma, Ann M. Bode, Zigang Dong. Targeting PRPK function blocks colon cancer metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1113.

Abstract 536: Targeting PRPK and TOPK for skin cancer prevention and therapy

Abstract Solar ultraviolet (sUV) irradiation is a major environmental carcinogen that can cause inflammation and skin cancer. The costs and morbidity associated with skin cancer are increasing, thus identifying molecules that can help prevent skin carcinogenesis is important. In this study, we identified the p53-related protein kinase (PRPK) as a novel oncogenic protein that is phosphorylated by the T-LAK cell-originated protein kinase (TOPK). Knockdown of TOPK inhibited PRPK phosphorylation and conferred resistance to solar simulated light (SSL)-induced skin carcinogenesis in mouse models. In the clinic, acute SSL irradiation significantly increased epidermal thickness as well as total protein and phosphorylation levels of TOPK and PRPK in human skin tissues. We identified two PRPK inhibitors, FDA-approved rocuronium bromide (Zemuron®) or betamethasone 17-valerate (Betaderm®) that could attenuate TOPK-dependent PRPK signaling. Importantly, topical application of either rocuronium or betamethasone attenuated SSL-induced epidermal hyperplasia, neovascularization and cutaneous squamous cell carcinoma (cSCC) development in SKH1 (Crl: SKH1-Hrhr) hairless mice by inhibiting PRPK activation, and also reduced expression of the proliferation and oncogenesis markers COX-2, cyclin D1 and MMP-9. This study is the first to demonstrate that PRPK- targeted therapy could be useful against sUV-induced cSCC. Citation Format: Eunmiri Roh, Mee-Hyun Lee, Tatyana A. Zykova, Feng Zhu, Hong-Gyum Kim, Ki Beom Bae, Yong Yeon Cho, Ann M. Bode, Zigang Dong. Targeting PRPK and TOPK for skin cancer prevention and therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 536.