Gene Summary

Gene:GUSB; glucuronidase beta
Aliases: BG, MPS7
Summary:This gene encodes a hydrolase that degrades glycosaminoglycans, including heparan sulfate, dermatan sulfate, and chondroitin-4,6-sulfate. The enzyme forms a homotetramer that is localized to the lysosome. Mutations in this gene result in mucopolysaccharidosis type VII. Alternative splicing results in multiple transcript variants. There are many pseudogenes of this locus in the human genome.[provided by RefSeq, May 2014]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 15 March, 2017


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

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Latest Publications: GUSB (cancer-related)

Song W, Zhang WH, Zhang H, et al.
Validation of housekeeping genes for the normalization of RT-qPCR expression studies in oral squamous cell carcinoma cell line treated by 5 kinds of chemotherapy drugs.
Cell Mol Biol (Noisy-le-grand). 2016; 62(13):29-34 [PubMed] Related Publications
Reverse transcription quantitative polymerase chain reaction (RT-qPCR) has become a frequently used strategy in gene expression studies. The relative quantification method is an important and commonly used method for the evaluation of RT-qPCR data. The key of this method is to identify an applicable internal control gene because the usage of different internal control genes may lead to distinct conclusions. Herein, we report the validation of 12 common housekeeping genes for RT-qPCR for gene expression analysis in the Oral squamous cell carcinoma (OSCC) cell line (KB and Tca-8113) treated by 5 kinds of Chemotherapy Drugs. The gene expression stability and applicability of the 12 housekeeping gene candidates were determined using the geNorm, NormFinder, and BestKeeper software programs. Comprehensive analyzing the results of the three software, ALAS1/GAPDH, ALAS1 and GUSB were suggested to be the most stable candidate genes for the study of both KB and Tca-8113 cell line together, KB cell line, and Tca-8113 cell line, respectively. This study provides useful information to normalize gene expression accurately for the investigation of target gene profiling in cell lines of OSCC. Further clarification of tumor molecular expression markers with our recommended housekeeping genes may improve the accuracy of diagnosis and estimation of prognostic factors as well as provide novel personalized treatments for OSCC patients.

Dragoj M, Milosevic Z, Bankovic J, et al.
Targeting CXCR4 and FAK reverses doxorubicin resistance and suppresses invasion in non-small cell lung carcinoma.
Cell Oncol (Dordr). 2017; 40(1):47-62 [PubMed] Related Publications
BACKGROUND: Current high lung cancer mortality rates are mainly due to the occurrence of metastases and therapeutic resistance. Therefore, simultaneous targeting of these processes may be a valid approach for the treatment of this type of cancer. Here, we assessed relationships between CXC chemokine receptor type 4 (CXCR4) and focal adhesion kinase (FAK) gene expression levels and expression levels of the drug resistance-related genes ABCB1 and ABCC1, and tested the potential of CXCR4 and FAK inhibitors to reverse doxorubicin (DOX) resistance and to decrease the invasive capacity of non-small cell lung carcinoma (NSCLC) cells.
METHODS: qRT-PCR was used for gene expression analyses in primary lung tissue samples obtained from 30 NSCLC patients and the human NSCLC-derived cell lines NCI-H460, NCI-H460/R and COR-L23. MTT, flow cytometry, cell death and β-galactosidase activity assays were used to assess the in vitro impact of CXCR4 and FAK inhibitors on DOX sensitivity. In addition, invasion and gelatin degradation assays were used to assess the in vitro impact of the respective inhibitors on metastasis-related processes in combination with DOX treatment.
RESULTS: We found that ABCB1 over-expression was significantly associated with CXCR4 and FAK over-expression, whereas ABCC1 over-expression was associated with increased FAK expression. We also found that CXCR4 and FAK inhibitors strongly synergized with DOX in reducing cell viability, arresting the cell cycle in the S or G2/M phases and inducing senescence. Additionally, we found that DOX enhanced the anti-invasive potential of CXCR4 and FAK inhibitors by reducing gelatin degradation and invasion.
CONCLUSIONS: From our data we conclude that targeting of CXCR4 and FAK may overcome ABCB1 and ABCC1-dependent DOX resistance in NSCLC cells and that simultaneous treatment of these cells with DOX may potentiate the anti-invasive effects of CXCR4 and FAK inhibitors.

Gümbel D, Gelbrich N, Weiss M, et al.
New Treatment Options for Osteosarcoma - Inactivation of Osteosarcoma Cells by Cold Atmospheric Plasma.
Anticancer Res. 2016; 36(11):5915-5922 [PubMed] Related Publications
BACKGROUND/AIM: Cold atmospheric plasma has been shown to inhibit tumor cell growth and induce tumor cell death. The aim of the study was to investigate the effects of cold atmospheric plasma treatment on proliferation of human osteosarcoma cells and to characterize the underlying cellular mechanisms.
MATERIALS AND METHODS: Human osteosarcoma cells (U2-OS and MNNG/HOS) were treated with cold atmospheric plasma and seeded in culture plates. Cell proliferation, p53 and phospho-p53 protein expression and nuclear morphology were assessed.
RESULTS: The treated human osteosarcoma cell lines exhibited attenuated proliferation rates by up to 66%. The cells revealed an induction of p53, as well as phospho-p53 expression, by 2.3-fold and 4.5-fold, respectively, compared to controls. 4',6-diamidino-2-phenylindole staining demonstrated apoptotic nuclear condensation following cold atmospheric plasma treatment.
CONCLUSION: Cold atmospheric plasma treatment significantly attenuated cell proliferation in a preclinical in vitro osteosarcoma model. The resulting increase in p53 expression and phospho-activation in combination with characteristic nuclear changes indicate this was through induction of apoptosis.

Murakami S, Motohashi H
Recent advances in elucidating KEAP1-NRF2 functions in hematopoietic/immune cells and leukemic cells.
Rinsho Ketsueki. 2016; 57(10):1860-1868 [PubMed] Related Publications
The KEAP1-NRF2 system is an inducible molecular mechanism enhancing transcriptions of several cytoprotective genes in response to xenobiotics and oxidative stress. Recently, the KEAP1-NRF2 system has been suggested to directly regulate a portion of the genes related to cell proliferation and differentiation. In hematopoietic cells, NRF2 activation plays a role in maintenance and cell fate determination of hematopoietic stem cells, as well as in maturation processes and homeostasis of megakaryocytes and erythrocytes. In addition, NRF2 activation has been reported to suppress the production and secretion of inflammatory cytokines, thereby exerting anti-inflammatory effects. An NRF2 inducer, BG-12, was recently approved as a drug for multiple sclerosis. In contrast, in acute myeloid leukemia, the leukemia cells reportedly have higher NRF2 mRNA levels that lead to an increase in NRF2 protein abundance, by which these cells acquire high resistance to anticancer drugs. Therefore, both NRF2 activators and inhibitors are promising agents for the development of effective therapies for chronic inflammation and leukemia, respectively.

Atanasova S, Nikolova B, Murayama S, et al.
Electroinduced Delivery of Hydrogel Nanoparticles in Colon 26 Cells, Visualized by Confocal Fluorescence System.
Anticancer Res. 2016; 36(9):4601-6 [PubMed] Related Publications
BACKGROUND: Nano-scale drug delivery systems (nano-DDS) are under intense investigation. Nano-platforms are developed for specific administration of small molecules, drugs, genes, contrast agents [quantum dots (QDs)] both in vivo and in vitro. Electroporation is a biophysical phenomenon which consists of the application of external electrical pulses across the cell membrane. The aim of this study was to research electro-assisted Colon 26 cell line internalization of QDs and QD-loaded nano-hydrogels (polymersomes) visualized by confocal microscopy and their influence on cell viability.
MATERIALS AND METHODS: The experiments were performed on the Colon 26 cancer cell line, using a confocal fluorescent imaging system and cell viability test.
RESULTS: Electroporation facilitated the delivery of nanoparticles in vivo. We demonstrated increased voltage-dependent delivery of nanoparticles into cells after electrotreatment, without significant cell viability reduction.
CONCLUSION: The delivery and retention of the polymersomes in vitro is a promising tool for future cancer treatment strategies and nanomedcine.

Todorovic Balint M, Jelicic J, Mihaljevic B, et al.
Gene Mutation Profiles in Primary Diffuse Large B Cell Lymphoma of Central Nervous System: Next Generation Sequencing Analyses.
Int J Mol Sci. 2016; 17(5) [PubMed] Free Access to Full Article Related Publications
The existence of a potential primary central nervous system lymphoma-specific genomic signature that differs from the systemic form of diffuse large B cell lymphoma (DLBCL) has been suggested, but is still controversial. We investigated 19 patients with primary DLBCL of central nervous system (DLBCL CNS) using the TruSeq Amplicon Cancer Panel (TSACP) for 48 cancer-related genes. Next generation sequencing (NGS) analyses have revealed that over 80% of potentially protein-changing mutations were located in eight genes (CTNNB1, PIK3CA, PTEN, ATM, KRAS, PTPN11, TP53 and JAK3), pointing to the potential role of these genes in lymphomagenesis. TP53 was the only gene harboring mutations in all 19 patients. In addition, the presence of mutated TP53 and ATM genes correlated with a higher total number of mutations in other analyzed genes. Furthermore, the presence of mutated ATM correlated with poorer event-free survival (EFS) (p = 0.036). The presence of the mutated SMO gene correlated with earlier disease relapse (p = 0.023), inferior event-free survival (p = 0.011) and overall survival (OS) (p = 0.017), while mutations in the PTEN gene were associated with inferior OS (p = 0.048). Our findings suggest that the TP53 and ATM genes could be involved in the molecular pathophysiology of primary DLBCL CNS, whereas mutations in the PTEN and SMO genes could affect survival regardless of the initial treatment approach.

Shin S, Go RE, Kim CW, et al.
Effect of benzophenone-1 and octylphenol on the regulation of epithelial-mesenchymal transition via an estrogen receptor-dependent pathway in estrogen receptor expressing ovarian cancer cells.
Food Chem Toxicol. 2016; 93:58-65 [PubMed] Related Publications
Epithelial-mesenchymal transition (EMT) is an important process in embryonic development and cancer progression and metastasis. EMT is influenced by 17β-estradiol (E2), an endogenous estrogen. Benzophenone-1 (2,4-dihydroxybenzophenone, BP-1) and 4-tert-octylphenol (OP) are suspected endocrine disrupting chemicals (EDCs) because they can exhibit estrogenic properties. In this study, we examined whether BP-1 and OP can lead to EMT of BG-1 ovarian cancer cells expressing estrogen receptors (ERs). A wound healing assay and western blot assay were conducted to show the effect of BP-1 and OP on the migration of BG-1 cells and protein expression of EMT-related genes. BP-1 (10(-6) M) and OP (10(-6) M) significantly enhanced the migration capability of BG-1 cells by reducing the wounded area in the cell monolayer relative to the control, similar to E2 (10(-9) M). However, when BG-1 cells were co-treated with ICI 182,780, an ER antagonist, the uncovered area was maintained at the level of the control. N-cadherin, snail, and slug were increased by BP-1 and OP while E-cadherin was reduced compared to the control. However, this effect was also restored by co-treatment with ICI 182,780. Taken together, these results indicate that BP-1 and OP, the potential EDCs, may have the ability to induce ovarian cancer metastasis via regulation of the expression of EMT markers and migration of ER-expressing BG-1 ovarian cancer cells.

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

Yusein-Myashkova S, Stoykov I, Gospodinov A, et al.
The repair capacity of lung cancer cell lines A549 and H1299 depends on HMGB1 expression level and the p53 status.
J Biochem. 2016; 160(1):37-47 [PubMed] Related Publications
Elucidation of the cellular components responsive to chemotherapeutic agents as cisplatin rationalizes the strategy for anticancer chemotherapy. The removal of the cisplatin/DNA lesions gives the chance to the cancer cells to survive and compromises the chemotherapeutical treatment. Therefore, the cell repair efficiency is substantial for the clinical outcome. High mobility group box 1 (HMGB1) protein is considered to be involved in the removal of the lesions as it binds with high affinity to cisplatin/DNA adducts. We demonstrated that overexpression of HMGB1 protein inhibited cis-platinated DNA repair in vivo and the effect strongly depended on its C-terminus. We registered increased levels of DNA repair after HMGB1 silencing only in p53 defective H1299 lung cancer cells. Next, introduction of functional p53 resulted in DNA repair inhibition. H1299 cells overexpressing HMGB1 were significantly sensitized to treatment with cisplatin demonstrating the close relation between the role of HMGB1 in repair of cis-platinated DNA and the efficiency of the anticancer drug, the process being modulated by the C-terminus. In A549 cells with functional p53, the repair of cisplatin/DNA adducts is determined by а complex action of HMGB1 and p53 as an increase of DNA repair capacity was registered only after silencing of both proteins.

Varbanova V, Naumova E, Mihaylova A
Killer-cell immunoglobulin-like receptor genes and ligands and their role in hematologic malignancies.
Cancer Immunol Immunother. 2016; 65(4):427-40 [PubMed] Related Publications
Natural killer (NK) cells are considered crucial for the elimination of emerging tumor cells. Effector NK-cell functions are controlled by interactions of inhibitory and activating killer-cell immunoglobulin-like receptors (KIRs) on NK cells with human leukocyte antigen (HLA) class I ligands on target cells. KIR and HLA are highly polymorphic genetic systems segregating independently, creating a great diversity in KIR/HLA gene profiles in different individuals. There is an increasing evidence supporting the relevance of KIR and HLA ligand gene background for the occurrence and outcome of certain cancers. However, the data are still controversial and the mechanisms of receptor-ligand mediated NK-cell action remain unclear. Here, the main characteristics and functions of KIRs and their HLA class I ligands are reviewed. In addition, we review the HLA and KIR correlations with different hematological malignancies and discuss our current understanding of the biological significance and mechanisms underlying these associations.

Andrici J, Goeppert B, Sioson L, et al.
Loss of BAP1 Expression Occurs Frequently in Intrahepatic Cholangiocarcinoma.
Medicine (Baltimore). 2016; 95(2):e2491 [PubMed] Free Access to Full Article Related Publications
BRCA1-associated protein 1 (BAP1) is a deubiquitinating enzyme that functions as a tumor suppressor gene. Double hit BAP1 inactivation has been reported in a range of tumor types, including intrahepatic cholangiocarcinoma (ICC), sometimes in association with germline mutation.We performed immunohistochemistry for BAP1 on a well-characterized cohort of 211 ICC patients undergoing surgical resection with curative intent at 3 institutions based in 3 different countries. The median age at diagnosis was 65 years (range, 36.5-86) and 108 (51%) were men. Negative staining for BAP1 (defined as completely absent nuclear staining in the presence of positive internal controls in nonneoplastic cells) occurred in 55 ICCs (26%). BAP1 loss predicted a strong trend toward improved median survival of 40.80 months (95% CI, 28.14-53.46) versus 24.87 months (95% CI, 18.73-31.01), P = 0.059). In a multivariate model including age, sex, BAP1 status, tumor stage, tumor grade, lymphovascular invasion, and tumor size, female sex was associated with improved survival (hazard ratio [HR] 0.54; 95% CI, 0.34-0.85), while advanced tumor stage and lymphovascular invasion (HR 1.89; 95% CI, 1.09-3.28) correlated with decreased survival. In a multivariate analysis, high grade tumors were associated with BAP1 loss (odds ratio [OR] 3.32; 95% CI, 1.29-8.55), while lymphatic invasion was inversely associated with BAP1 loss (OR 0.36; 95% CI, 0.13-0.99).In conclusion, we observed a trend toward improved prognosis in ICC associated with absent expression of BAP1 and an association of BAP1 loss with higher histological grade and absent lymphatic invasion. Female sex was associated with improved survival while advanced tumor stage and lymphatic invasion were associated with decreased survival.

Hu HH, Kannengiesser C, Lesage S, et al.
PARKIN Inactivation Links Parkinson's Disease to Melanoma.
J Natl Cancer Inst. 2016; 108(3) [PubMed] Related Publications
BACKGROUND: Melanoma incidence is higher in patients affected by Parkinson's disease (PD) and vice versa, but the genetic link shared by both diseases is unknown. As PARK2 is both a tumor suppressor gene and frequently mutated in young onset PD, we evaluated the role of PARK2 in melanoma predisposition and progression.
METHODS: An in-depth PARK2 gene dosage analysis and sequencing was performed on 512 French case patients and 562 healthy control patients, as well as sporadic tumors and melanoma cell lines. The frequency of genetic alterations was compared between case patients and control patients using two-sided Fisher's exact tests and odds ratio (OR) calculations. We used western blotting to determine PARKIN expression in melanocytes and melanoma cell lines and transfection followed by clonogenic assays to evaluate the effect of PARKIN expression on cellular proliferation. All statistical tests were two-sided.
RESULTS: Germline PARK2 mutations (including copy number variations, splicing, and putative deleterious missense mutations) were present in 25 case patients but only four control patients (OR = 3.95, 95% confidence interval = 1.34 to 15.75). Copy number variations (CNVs) and loss of heterozygosity were present in 60% and 74%, respectively, of primary tumors. PARKIN protein was expressed in melanocytes but not in most melanoma cell lines, and its expression decreased following melanocyte transformation by oncogenic NRAS. Re-expression of PARKIN in melanoma cell lines resulted in a drastic reduction of cell proliferation and inhibition of PARKIN in melanocytes stimulated their proliferation.
CONCLUSION: Our results show an important role for PARK2 as a tumor suppressor both in melanoma predisposition and progression, which could explain the epidemiological association of these diseases.

Čokić VP, Mojsilović S, Jauković A, et al.
Gene expression profile of circulating CD34(+) cells and granulocytes in chronic myeloid leukemia.
Blood Cells Mol Dis. 2015; 55(4):373-81 [PubMed] Free Access to Full Article Related Publications
PURPOSE: We compared the gene expression profile of peripheral blood CD34(+) cells and granulocytes in subjects with chronic myeloid leukemia (CML), with the accent on signaling pathways affected by BCR-ABL oncogene.
METHODS: The microarray analyses have been performed in circulating CD34(+) cells and granulocytes from peripheral blood of 7 subjects with CML and 7 healthy donors. All studied BCR-ABL positive CML patients were in chronic phase, with a mean value of 2012±SD of CD34(+)cells/μl in peripheral blood.
RESULTS: The gene expression profile was more prominent in CML CD34(+) cells (3553 genes) compared to granulocytes (2701 genes). The 41 and 39 genes were significantly upregulated in CML CD34(+) cells (HINT1, TXN, SERBP1) and granulocytes, respectively. BCR-ABL oncogene activated PI3K/AKT and MAPK signaling through significant upregulation of PTPN11, CDK4/6, and MYC and reduction of E2F1, KRAS, and NFKBIA gene expression in CD34(+) cells. Among genes linked to the inhibition of cellular proliferation by BCR-ABL inhibitor Imatinib, the FOS and STAT1 demonstrated significantly decreased expression in CML.
CONCLUSION: The presence of BCR-ABL fusion gene doubled the expression quantity of genes involved in the regulation of cell cycle, proliferation and apoptosis of CD34(+) cells. These results determined the modified genes in PI3K/AKT and MAPK signaling of CML subjects.

Santoro M, Guido C, De Amicis F, et al.
Bergapten induces metabolic reprogramming in breast cancer cells.
Oncol Rep. 2016; 35(1):568-76 [PubMed] Related Publications
Alterations in cellular metabolism are among the most consistent hallmarks of cancer. Herein, after a comprehensive metabolic phenotype characterization of MCF7 and ZR75 breast cancer cells, we investigated the activity of bergapten (Bg), a plant-derived compound, against breast cancer. The study of different biochemical pathways involved in cell metabolism revealed that the two cell lines have different bioenergetic phenotypes: MCF7 cells express a glycolytic phenotype only partially oxidative, while ZR75 cells mainly have an oxidative phenotype. In both cell lines, Bg blocked glycolysis and significantly decreased glucose-6-phosphate dehydrogenase (G6PDH) activity promoting glucose accumulation; modulated bioenergetic requirements altering the expression of oxidative phosphorylation (OXPHOS) complexes and ATP production; and induced a lipid-lowering effect since an increased lipase activity concomitantly to a reduction in triglyceride levels was observed. Quantitative data of different metabolites and enzymatic activities were presented. Treatment with Bg resulted in an alteration in different metabolic pathways inducing death in the cells. We report a novel action of the natural product Bg on breast cancer, since it induced metabolic reprogramming by disrupting the interconnected network of different metabolic mechanisms. Bg can be used in combination with other forms of targeted chemotherapy to improve cancer treatment outcomes.

Dinic J, Podolski-Renic A, Stankovic T, et al.
New Approaches With Natural Product Drugs for Overcoming Multidrug Resistance in Cancer.
Curr Pharm Des. 2015; 21(38):5589-604 [PubMed] Related Publications
Resistance to chemotherapeutic drugs is one of the main obstacles to effective cancer treatment. Multidrug resistance (MDR) is defined as resistance to structurally and/or functionally unrelated drugs, and has been extensively investigated for the last three decades. There are two types of MDR: intrinsic and acquired. Tumor microenvironment selection pressure leads to the development of intrinsic MDR, while acquired resistance is a consequence of the administered chemotherapy. A central issue in chemotherapy failure is the existence of heterogeneous populations of cancer cells within one patient and patient-to-patient variability within each type of cancer. Numerous genes and pathways contribute to the development of MDR in cancer. Point mutations, gene amplification or other genetic or epigenetic changes all affect biological functions and may lead to the occurrence of MDR phenotype. Similar to the characteristics of cancerogenesis, the main features of MDR include abnormal tumor vasculature, regions of hypoxia, aerobic glycolysis, and a lower susceptibility to apoptosis. In order to achieve a lethal effect on cancer cells, drugs need to reach their intracellular target molecules. The overexpression of the efflux transporter P-glycoprotein (P-gp) in MDR cancer cells leads to decreased uptake of the drug and intracellular drug accumulation, minimising drug-target interactions. New agents being or inspired by natural products that successfully target these mechanisms are the main subject of this review. Two key approaches in combating MDR in cancer are discussed (i) finding agents that preserve cytotoxicity toward MDR cancer cells; (ii) developing compounds that restore the cytotoxic activity of classic anticancer drugs.

Kim YS, Choi KC, Hwang KA
Genistein suppressed epithelial-mesenchymal transition and migration efficacies of BG-1 ovarian cancer cells activated by estrogenic chemicals via estrogen receptor pathway and downregulation of TGF-β signaling pathway.
Phytomedicine. 2015; 22(11):993-9 [PubMed] Related Publications
BACKGROUND: Epithelial-mesenchymal transition (EMT), which is activated by 17β-estradiol (E2) in estrogen-responsive cancers, is an important process in tumor migration or progression. As typical endocrine disrupting chemicals (EDCs), bisphenol A (BPA) and nonylphenol (NP) have a potential to promote EMT and migration of estrogen-responsive cancers. On the contrary, genistein (GEN) as a phytoestrogen is known to have chemopreventive effects in diverse cancers.
METHODS: In the present study, the effects of BPA and GEN on EMT and the migration of BG-1 ovarian cancer cells and the underlying mechanism were investigated. ICI 182,780, an estrogen receptor (ER) antagonist, was co-treated with E2 or BPA or NP to BG-1 cells to identify the relevance of ER signaling in EMT and migration.
RESULTS: As results, E2 and BPA upregulated the protein expression of vimentin, cathepsin D, and MMP-2, but downregulated the protein expression of E-cadherin via ER signaling pathway, suggesting that E2 and BPA promote EMT and cell migration related gene expressions. However, the increased protein expressions of vimentin, cathepsin D, and MMP-2 by E2, BPA, or NP were reduced by the co-treatment of GEN. In a scratch assay, the migration capability of BG-1 cells was enhanced by E2, BPA, and NP via ER signaling but reversed by the co-treatment of GEN. In the protein expression of SnoN and Smad3, E2, BPA, and NP upregulated SnoN, a negative regulator of TGF-β signaling, and downregulated pSmad3, a transcription factor in the downstream pathway of TGF-β signaling pathway, suggesting that E2, BPA, and NP simultaneously lead to the downregualtion of TGF-β signaling in the process of induction of EMT and migration of BG-1 cells via ER signaling. On the other hand, the co-treatment of GEN reversed the downregulation of TGF-β signaling by estrogenic chemicals.
CONCLUSION: Taken together, GEN suppressed EMT and migration capacities of BG-1 ovarian cancer cells enhanced by E2, BPA, and NP via ER signaling and the downregulation of TGF-β signal.

Nikolic N, Anicic B, Carkic J, et al.
High frequency of p16 and p14 promoter hypermethylation and marked telomere instability in salivary gland tumors.
Arch Oral Biol. 2015; 60(11):1662-6 [PubMed] Related Publications
OBJECTIVES: to investigate p16(INK4a) and p14(ARF) tumor suppressor gene methylation status, determine telomere length and assess the importance of these epigenetic and genetic parameters in the development of pleomorphic adenoma and carcinoma ex pleomorphic adenoma of the parotid salivary glands.
MATERIALS AND METHODS: Genomic DNA from paraffin-embedded samples of 50 pleomorphic adenomas and 10 carcinomas ex pleomorphic adenoma was subjected to methylation specific polymerase chain reaction for hypermethylation analyses and real time polymerase chain reaction for the relative telomere length calculations.
RESULTS: Promoter hypermethylation of the two genes was a very frequent event in both neoplasms - between 60% and 90% of samples were hypermethylated - but without significant difference between the groups. The mean relative telomere length in the pleomorphic adenoma group was significantly increased in comparison to the control group (P=0.00), and significantly decreased in comparison to the carcinoma group (P=0.05). Telomeres were also longer in myxoid and cellular histological subtypes of adenomas than in the classic type (P=0.044 and P=0.018, respectively). Longer telomeres were more frequent in tumors with hypermethylated p14(ARF) alleles (P=0.013).
CONCLUSION: Promoter hypermethylations seems to be an important mechanism of p16(INK4a) and p14(ARF) inactivation in parotid gland tumors. Telomeric lengthening appears to be involved in the pathogenesis of both benign and malignant tumors of the parotid glands.

Go RE, Kim CW, Choi KC
Effect of fenhexamid and cyprodinil on the expression of cell cycle- and metastasis-related genes via an estrogen receptor-dependent pathway in cellular and xenografted ovarian cancer models.
Toxicol Appl Pharmacol. 2015; 289(1):48-57 [PubMed] Related Publications
Fenhexamid and cyprodinil are antifungal agents (pesticides) used for agriculture, and are present at measurable amounts in fruits and vegetables. In the current study, the effects of fenhexamid and cyprodinil on cancer cell proliferation and metastasis were examined. Additionally, the protein expression levels of cyclin D1 and cyclin E as well as cathepsin D were analyzed in BG-1 ovarian cancer cells that express estrogen receptors (ERs). The cells were cultured with 0.1% dimethyl sulfoxide (DMSO; control), 17β-estradiol (E2; 10(-9)M), and fenhexamid or cyprodinil (10(-5)-10(-7)M). Results of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that fenhexamid and cyprodinil increased BG-1 cell proliferation about 1.5 to 2 times similar to E2 (5 times) compared to the control. When the cells were co-treated with ICI 182,780 (10(-8)M), an ER antagonist, the proliferation of pesticide-treated BG-1 cells was decreased to the level of the control. A wound healing assay revealed that the pesticides reduced the disrupted area in the BG-1 cell monolayer similar to E2. Protein levels of cyclin D1 and E as well as cathepsin D were increased by fenhexamid and cyprodinil. This effect was reversed by co-treatment with ICI 182,780. In a xenograft mouse model with transplanted BG-1 cells, cyprodinil significantly increased tumor mass formation about 2 times as did E2 (6 times) compared to the vehicle (0.1% DMSO) over an 80-day period. In contrast, fenhexamid did not promote ovarian tumor formation in this mouse model. Cyprodinil also induced cell proliferation along with the expression of proliferating cell nuclear antigen (PCNA) and cathepsin D in tumor tissues similar to E2. Taken together, these results imply that fenhexamid and cyprodinil may have disruptive effects on ER-expressing cancer by altering the cell cycle- and metastasis-related gene expression via an ER-dependent pathway.

Sarkar N, Chakravarty R
Hepatitis B Virus Infection, MicroRNAs and Liver Disease.
Int J Mol Sci. 2015; 16(8):17746-62 [PubMed] Free Access to Full Article Related Publications
Hepatitis B virus (HBV) attacks the liver and can cause both acute as well as chronic liver diseases which might lead to liver cirrhosis and hepatocellular carcinoma. Regardless of the availability of a vaccine and numerous treatment options, HBV is a major cause of morbidity and mortality across the world. Recently,microRNAs (miRNAs) have emerged as important modulators of gene function. Studies on the role of miRNA in the regulation of hepatitis B virus gene expression have been the focus of modern antiviral research. miRNAs can regulate viral replication and pathogenesis in a number of different ways, which includefacilitation, direct or indirect inhibition, activation of immune response, epigenetic modulation, etc. Nevertheless, these mechanisms can appropriately be used with a diagnosticand/or therapeutic approach. The present review is an attempt to classify specific miRNAs that are reported to be associated with various aspects of hepatitis B biology, in order to precisely present the participation of individual miRNAs in multiple aspects relating to HBV.

Nikolić Z, Savić Pavićević D, Vučić N, et al.
Assessment of association between genetic variants in microRNA genes hsa-miR-499, hsa-miR-196a2 and hsa-miR-27a and prostate cancer risk in Serbian population.
Exp Mol Pathol. 2015; 99(1):145-50 [PubMed] Related Publications
Due to their potentially functional significance, genetic variants within microRNA genes have been recognized as candidates for cancer-related genetic biomarkers. Among the most extensively studied so far are rs3746444, rs11614913 and rs895819. Nevertheless, only few previous studies in Asian population analyzed the association of rs3746444 and rs11614913 with prostate cancer (PCa) risk, while rs895819 was not evaluated in relation to this issue. The aim of this study was to assess the possible association between these genetic variants and PCa risk and progression in Serbian population. 355 samples of peripheral blood were obtained from the patients with PCa and 353 samples from patients with benign prostatic hyperplasia (BPH). 312 volunteers derived from general population who gave samples of buccal swabs were included in the control group. Genotyping of rs3746444, rs11614913 and rs895819 was performed by using PCR-RFLP method, HRM analysis and allele-specific PCR, respectively. Allelic and genotypic associations were evaluated by unconditional linear (for serum PSA level in PCa patients) and logistic regression method with adjustment for age. Minor allele C of rs895819 was found to be associated with the increased risk of developing PCa under dominant (P=0.035; OR=1.38, 95%CI 1.02-1.86) and overdominant (P=0.04; OR=1.37, 95%CI 1.01-1.85) genetic model. Same genetic variant was found to be associated with the clinical stage of localized PCa, as well as with the presence of distant metastases. Allele G of rs3746444 was also shown to be associated with the decreased risk of PCa progression. According to our data, rs3746444 qualifies for a genetic variant potentially associated with PCa aggressiveness in Serbian population. Furthermore, our study provided the first evidence of association between rs895819 and PCa risk, as well as for its genetic association with the presence of distant metastases among PCa patients.

Nikolic A, Ristanovic M, Zivaljevic V, et al.
SMAD4 gene promoter mutations in patients with thyroid tumors.
Exp Mol Pathol. 2015; 99(1):100-3 [PubMed] Related Publications
As a key component of the transforming growth factor beta (TGFB) pathway, which regulates the expression of thyroid-specific genes, tumor suppressor SMAD4 is crucial for thyroid development and function. Aberrant expression of SMAD4 in thyroid tumor tissue was reported and mutations affecting the coding region have been detected, but a potential role of mutations in SMAD4 gene regulatory regions remains unexplored. The aim of this study was to analyze SMAD4 gene promoters in thyroid tumors. A total of 76 thyroidectomy specimens were studied, including 42 malignant and 34 benign tumors. The presence of mutations in four SMAD4 gene promoters was analyzed in thyroid tumor tissue and peripheral blood by PCR and DNA sequencing. The expression and intracellular localization of endogenous SMAD4 protein in selected tumor samples was studied by immunostaining and confocal microscopy. Of three novel variants detected, two were within promoter A (-204T/C and -5C/T) and one in promoter D (-180delA). Unlike somatic mutations previously detected in the nearby region, germline mutation -180delA in promoter D doesn't appear to affect SMAD4 expression in the thyroid tumor tissue. However, all newly detected SMAD4 promoter variants affect predicted binding sites of transcription factors involved in cell cycle regulation and should be further characterized functionally. Although not directly involved in carcinogenesis, detected variants may alter SMAD4 transcriptional regulation to some extent. Considering that dosage dependence is of great importance for the role of SMAD4 protein as a tumor suppressor, potential clinical significance of SMAD4 gene promoter mutations is worth further investigation.

Dragoj M, Milosevic Z, Bankovic J, et al.
Association of CCND1 overexpression with KRAS and PTEN alterations in specific subtypes of non-small cell lung carcinoma and its influence on patients' outcome.
Tumour Biol. 2015; 36(11):8773-80 [PubMed] Related Publications
Cyclin D1 is one of the major cellular oncogenes, overexpressed in number of human cancers, including non-small cell lung carcinoma (NSCLC). However, it does not exert tumorigenic activity by itself, but rather cooperates with other altered oncogenes and tumor suppressors. Therefore, in the present study, we have examined mutual role of cyclin D1, KRAS, and PTEN alterations in the pathogenesis of NSCLC and their potential to serve as multiple molecular markers for this disease. CCND1 gene amplification and gene expression were analyzed in relation to mutational status of KRAS gene as well as to PTEN alterations (loss of heterozygosity and promoter hypermethylation) in NSCLC patient samples. Moreover, the effect of these co-alterations on patient survival was examined. Amplified CCND1 gene was exclusively associated with increased gene expression. Statistical analyses also revealed significant association between CCND1 overexpression and KRAS mutations in the whole group and in the groups of patients with adenocarcinoma, grade 1/2, and stage I/II. In addition, CCND1 overexpression was significantly related to PTEN promoter hypermethylation in the whole group and in the group of patients with squamous cell carcinoma and lymph node invasion. These joint alterations also significantly shortened patients' survival and were shown to be an independent factor for adverse prognosis. Overall results point that cyclin D1 expression cooperates with KRAS and PTEN alterations in pathogenesis of NSCLC, and they could serve as potential multiple molecular markers for specific subgroups of NSCLC patients as well as prognostic markers for this type of cancer.

Rossi ÚA, Gil-Cardeza ML, Villaverde MS, et al.
Interferon-β gene transfer induces a strong cytotoxic bystander effect on melanoma cells.
Biomed Pharmacother. 2015; 72:44-51 [PubMed] Related Publications
A local gene therapy scheme for the delivery of type I interferons could be an alternative for the treatment of melanoma. We evaluated the cytotoxic effects of interferon-β (IFNβ) gene lipofection on tumor cell lines derived from three human cutaneous and four canine mucosal melanomas. The cytotoxicity of human IFNβ gene lipofection resulted higher or equivalent to that of the corresponding addition of the recombinant protein (rhIFNβ) to human cells. IFNβ gene lipofection was not cytotoxic for only one canine melanoma cell line. When cultured as monolayers, three human and three canine IFNβ-lipofected melanoma cell lines displayed a remarkable bystander effect. As spheroids, the same six cell lines were sensitive to IFNβ gene transfer, two displaying a significant multicell resistance phenotype. The effects of conditioned IFNβ-lipofected canine melanoma cell culture media suggested the release of at least one soluble thermolabile cytotoxic factor that could not be detected in human melanoma cells. By using a secretion signal-free truncated human IFNβ, we showed that its intracellular expression was enough to induce cytotoxicity in two human melanoma cell lines. The lower cytoplasmatic levels of reactive oxygen species detected after intracellular IFNβ expression could be related to the resistance displayed by one human melanoma cell line. As IFNβ gene transfer was effective against most of the assayed melanomas in a way not limited by relatively low lipofection efficiencies, the clinical potential of this approach is strongly supported.

Shlensky D, Mirrielees JA, Zhao Z, et al.
Differential CARM1 Isoform Expression in Subcellular Compartments and among Malignant and Benign Breast Tumors.
PLoS One. 2015; 10(6):e0128143 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Coactivator-associated arginine methyltransferase 1 (CARM1) is a coactivator for ERα and cancer-relevant transcription factors, and can methylate diverse cellular targets including histones. CARM1 is expressed in one of two alternative splice isoforms, full-length CARM1 (CARM1FL) and truncated CARM1 (CARM1ΔE15). CARM1FL and CARM1ΔE15 function differently in transcriptional regulation, protein methylation, and mediation of pre-mRNA splicing in cellular models.
METHODS: To investigate the functional roles and the prognosis potential of CARM1 alternative spliced isoforms in breast cancer, we used recently developed antibodies to detect differential CARM1 isoform expression in subcellular compartments and among malignant and benign breast tumors.
RESULTS: Immunofluorescence in MDA-MB-231 and BG-1 cell lines demonstrated that CARM1ΔE15 is the dominant isoform expressed in the cytoplasm, and CARM1FL is more nuclear localized. CARM1ΔE15 was found to be more sensitive to Hsp90 inhibition than CARM1FL, indicating that the truncated isoform may be the oncogenic form. Clinical cancer samples did not have significantly higher expression of CARM1FL or CARM1ΔE15 than benign breast samples at the level of mRNA or histology. Furthermore neither CARM1FL nor CARM1ΔE15 expression correlated with breast cancer molecular subtypes, tumor size, or lymph node involvement.
CONCLUSIONS: The analysis presented here lends new insights into the possible oncogenic role of CARM1ΔE15. This study also demonstrates no obvious association of CARM1 isoform expression and clinical correlates in breast cancer. Recent studies, however, have shown that CARM1 expression correlates with poor prognosis, indicating a need for further studies of both CARM1 isoforms in a large cohort of breast cancer specimens.

Sharma R, Williams PJ, Gupta A, et al.
A dominant-negative F-box deleted mutant of E3 ubiquitin ligase, β-TrCP1/FWD1, markedly reduces myeloma cell growth and survival in mice.
Oncotarget. 2015; 6(25):21589-602 [PubMed] Free Access to Full Article Related Publications
Treatment of multiple myeloma with bortezomib can result in severe adverse effects, necessitating the development of targeted inhibitors of the proteasome. We show that stable expression of a dominant-negative F-box deleted (∆F) mutant of the E3 ubiquitin ligase, SCFβ-TrCP/FWD1, in murine 5TGM1 myeloma cells dramatically attenuated their skeletal engraftment and survival when inoculated into immunocompetent C57BL/KaLwRij mice. Similar results were obtained in immunodeficient bg-nu-xid mice, suggesting that the observed effects were independent of host recipient immune status. Bone marrow stroma offered no protection for 5TGM1-∆F cells in cocultures treated with tumor necrosis factor (TNF), indicating a cell-autonomous anti-myeloma effect. Levels of p100, IκBα, Mcl-1, ATF4, total and cleaved caspase-3, and phospho-β-catenin were elevated in 5TGM1-∆F cells whereas cIAP was down-regulated. TNF also activated caspase-3 and downregulated Bcl-2, correlating with the enhanced susceptibility of 5TGM1-∆F cells to apoptosis. Treatment of 5TGM1 tumor-bearing mice with a β-TrCP1/FWD1 inhibitor, pyrrolidine dithiocarbamate (PDTC), significantly reduced tumor burden in bone. PDTC also increased levels of cleaved Mcl-1 and caspase-3 in U266 human myeloma cells, correlating with our murine data and validating the development of specific β-TrCP inhibitors as an alternative therapy to nonspecific proteasome inhibitors for myeloma patients.

Ma G, He J, Yu Y, et al.
Tamoxifen inhibits ER-negative breast cancer cell invasion and metastasis by accelerating Twist1 degradation.
Int J Biol Sci. 2015; 11(5):618-28 [PubMed] Free Access to Full Article Related Publications
Twist1 is a transcription factor driving epithelial-mesenchymal transition, invasion and metastasis of breast cancer cells. Mice with germ-line Twist1 knockout are embryonic lethal, while adult mice with inducible Twist1 knockout have no obvious health problems, suggesting that Twist1 is a viable therapeutic target for the inhibition of invasion and metastasis of breast cancer in adult patients. In this study, we expressed a luciferase protein or a Twist1-luciferase fusion protein in HeLa cells as part of a high throughput system to screen 1280 compounds in the Library of Pharmacologically Active Compounds (LOPAC) from Sigma-Aldrich for their effects on Twist1 protein expression. One of the most interesting compounds identified is tamoxifen, a selective estrogen receptor (ER) modulator used to treat ER-positive breast cancer. Tamoxifen treatment significantly accelerated Twist1 degradation in multiple cell lines including HEK293 human kidney cells, 4T1 and 168FARN mouse mammary tumor cells with either ectopically or endogenously expressed Twist1. Tamoxifen-induced Twist1 degradation could be blocked by the MG132 proteasome inhibitor, suggesting that tamoxifen induces Twist1 degradation through the ubiquitination-proteasome pathway. However, tamoxifen-induced Twist1 degradation was independent of Twist1 mRNA expression, estrogen signaling and MAPK-mediated Twist1 phosphorylation in these cells. Importantly, tamoxifen also significantly inhibited invasive behavior in Matrigel and lung metastasis in SCID-bg mice of ER-negative 4T1 mammary tumor cells, which depend on endogenous Twist1 to invade and metastasize. These results indicate that tamoxifen can significantly accelerate Twist1 degradation to suppress cancer cell invasion and metastasis, suggesting that tamoxifen can be used not only to treat ER-positive breast cancers but also to reduce Twist1-mediated invasion and metastasis in ER-negative breast cancers.

Matuskova M, Kozovska Z, Toro L, et al.
Combined enzyme/prodrug treatment by genetically engineered AT-MSC exerts synergy and inhibits growth of MDA-MB-231 induced lung metastases.
J Exp Clin Cancer Res. 2015; 34:33 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Metastatic spread of tumor cells remains a serious problem in cancer treatment. Gene-directed enzyme/prodrug therapy mediated by tumor-homing genetically engineered mesenchymal stromal cells (MSC) represents a promising therapeutic modality for elimination of disseminated cells. Efficacy of gene-directed enzyme/prodrug therapy can be improved by combination of individual systems. We aimed to define the combination effect of two systems of gene therapy mediated by MSC, and evaluate the ability of systemically administered genetically engineered mesenchymal stromal cells to inhibit the growth of experimental metastases derived from human breast adenocarcinoma cells MDA-MB-231/EGFP.
METHODS: Human adipose tissue-derived mesenchymal stromal cells (AT-MSC) were retrovirally transduced with fusion yeast cytosine deaminase::uracil phosphoribosyltransferase (CD::UPRT) or with Herpes simplex virus thymidine kinase (HSVtk). Engineered MSC were cocultured with tumor cells in the presence of prodrugs 5-fluorocytosin (5-FC) and ganciclovir (GCV). Combination effect of these enzyme/prodrug approaches was calculated. SCID/bg mice bearing experimental lung metastases were treated with CD::UPRT-MSC, HSVtk-MSC or both in combination in the presence of respective prodrug(s). Treatment efficiency was evaluated by EGFP-positive cell detection by flow cytometry combined with real-time PCR quantification of human cells in mouse organs. Results were confirmed by histological and immunohistochemical examination.
RESULTS: We demonstrated various extent of synergy depending on tested cell line and experimental setup. The strongest synergism was observed on breast cancer-derived cell line MDA-MB-231/EGFP. Systemic administration of CD::UPRT-MSC and HSVtk-MSC in combination with 5-FC and GCV inhibited growth of MDA-MB-231 induced lung metastases.
CONCLUSIONS: Combined gene-directed enzyme/prodrug therapy mediated by MSC exerted synergic cytotoxic effect and resulted in high therapeutic efficacy in vivo.

Bancovik J, Moreira DF, Carrasco D, et al.
Dermcidin exerts its oncogenic effects in breast cancer via modulation of ERBB signaling.
BMC Cancer. 2015; 15:70 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: We previously identified dermicidin (DCD), which encodes a growth and survival factor, as a gene amplified and overexpressed in a subset of breast tumors. Patients with DCD-positive breast cancer have worse prognostic features. We therefore searched for specific molecular signatures in DCD-positive breast carcinomas from patients and representative cell lines.
METHODS: DCD expression was evaluated by qRT-PCR, immunohistochemical and immunoblot assays in normal and neoplastic tissues and cell lines. To investigate the role of DCD in breast tumorigenesis, we analyzed the consequences of its downregulation in human breast cancer cell lines using three specific shRNA lentiviral vectors. Genes up- and down-regulated by DCD were identified using Affymetrix microarray and analyzed by MetaCore Platform.
RESULTS: We identified DCD splice variant (DCD-SV) that is co-expressed with DCD in primary invasive breast carcinomas and in other tissue types and cell lines. DCD expression in breast tumors from patients with clinical follow up data correlated with high histological grade, HER2 amplification and luminal subtype. We found that loss of DCD expression led to reduced cell proliferation, resistance to apoptosis, and suppressed tumorigenesis in immunodeficient mice. Network analysis of gene expression data revealed perturbed ERBB signaling following DCD shRNA expression including changes in the expression of ERBB receptors and their ligands.
CONCLUSIONS: These findings imply that DCD promotes breast tumorigenesis via modulation of ERBB signaling pathways. As ERBB signaling is also important for neural survival, HER2+ breast tumors may highjack DCD's neural survival-promoting functions to promote tumorigenesis.

Bobustuc GC, Patel A, Thompson M, et al.
MGMT inhibition suppresses survivin expression in pancreatic cancer.
Pancreas. 2015; 44(4):626-35 [PubMed] Related Publications
OBJECTIVES: Survivin, an antiapoptotic gene inhibited by p53, is overexpressed in human cancers and correlates with chemotherapy resistance. Here, we investigated the mutual regulatory mechanism between MGMT (O-methylguanine DNA methyltransferase) and survivin.
METHODS: This study used standard techniques for protein and messenger RNA levels, promoter activity, protein-DNA interaction, cell viability, and correlative animal model.
RESULTS: O-benzylguanine (BG), a potent inhibitor of MGMT (a DNA repair protein), curtails the expression of survivin in pancreatic cancer. Silencing MGMT by small interfering RNA down-regulates survivin transcription. p53 inhibition enhances MGMT and survivin expressions. When p53 was silenced, BG-induced MGMT inhibition was not associated with the down-regulation of survivin, underscoring the regulatory role of p53 in the MGMT-survivin axis. O-benzylguanine inhibits survivin and PCNA (proliferating cell nuclear antigen) at messenger RNA and protein levels in PANC-1 and L3.6pl cells and decreases survivin promoter activity via increased p53 recruitment to the survivin promoter. In orthotopic pancreatic xenografts established in nude mice, BG ± gemcitabine (GEM) decrease survivin expression in tumor tissue; protein levels and immunohistochemistry show significant decrease in survivin and PCNA levels, which correlate with increased sensitivity to GEM.
CONCLUSIONS: MGMT inhibition is associated with decrease in survivin expression and increase in sensitivity to GEM in pancreatic cancer.

Lai IC, Shih PH, Yao CJ, et al.
Elimination of cancer stem-like cells and potentiation of temozolomide sensitivity by Honokiol in glioblastoma multiforme cells.
PLoS One. 2015; 10(3):e0114830 [PubMed] Free Access to Full Article Related Publications
Glioblastoma multiforme (GBM) is the most common adult malignant glioma with poor prognosis due to the resistance to radiotherapy and chemotherapy, which might be critically involved in the repopulation of cancer stem cells (CSCs) after treatment. We had investigated the characteristics of cancer stem-like side population (SP) cells sorted from GBM cells, and studied the effect of Honokiol targeting on CSCs. GBM8401 SP cells possessed the stem cell markers, such as nestin, CD133 and Oct4, and the expressions of self-renewal related stemness genes, such as SMO, Notch3 and IHH (Indian Hedgehog). Honokiol inhibited the proliferation of both GBM8401 parental cells and SP cells in a dose-dependent manner, the IC50 were 5.3±0.72 and 11±1.1 μM, respectively. The proportions of SP in GBM8401 cells were diminished by Honokiol from 1.5±0.22% down to 0.3±0.02% and 0.2±0.01% at doses of 2.5 μM and 5 μM, respectively. The SP cells appeared to have higher expression of O6-methylguanine-DNA methyltransferase (MGMT) and be more resistant to Temozolomide (TMZ). The resistance to TMZ could be only slightly reversed by MGMT inhibitor O6-benzylguanine (O6-BG), but markedly further enhanced by Honokiol addition. Such significant enhancement was accompanied with the higher induction of apoptosis, greater down-regulation of Notch3 as well as its downstream Hes1 expressions in SP cells. Our data indicate that Honokiol might have clinical benefits for the GBM patients who are refractory to TMZ treatment.

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