RFC1

Gene Summary

Gene:RFC1; replication factor C subunit 1
Aliases: A1, RFC, PO-GA, RECC1, MHCBFB, RFC140
Location:4p14
Summary:This gene encodes the large subunit of replication factor C, a five subunit DNA polymerase accessory protein, which is a DNA-dependent ATPase required for eukaryotic DNA replication and repair. The large subunit acts as an activator of DNA polymerases, binds to the 3' end of primers, and promotes coordinated synthesis of both strands. It may also have a role in telomere stability. Alternatively spliced transcript variants encoding different isoforms have been noted for this gene. [provided by RefSeq, Mar 2011]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:replication factor C subunit 1
Source:NCBIAccessed: 16 March, 2017

Ontology:

What does this gene/protein do?
Show (22)
Pathways:What pathways are this gene/protein implicaed in?
Show (1)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 16 March 2017 using data from PubMed using criteria.

Literature Analysis

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

  • Solute Carrier Organic Anion Transporter Family Member 1b1
  • Polymerase Chain Reaction
  • Replication Protein C
  • Case-Control Studies
  • Adolescents
  • Genetic Predisposition
  • Alleles
  • Sigmoidoscopy
  • Infant
  • Cancer Gene Expression Regulation
  • 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase
  • Reduced Folate Carrier Protein
  • Membrane Transport Proteins
  • Chromosome 4
  • Folic Acid
  • Young Adult
  • Metabolic Networks and Pathways
  • Childhood Cancer
  • Colorectal Cancer
  • Methylenetetrahydrofolate Reductase (NADPH2)
  • Genotype
  • Thymidylate Synthase
  • Cell Surface Receptors
  • Risk Factors
  • Antimetabolites, Antineoplastic
  • Smoking
  • Restriction Fragment Length Polymorphism
  • Pyrophosphatases
  • Drug Resistance
  • Tetrahydrofolate Dehydrogenase
  • Acute Lymphocytic Leukaemia
  • Nucleic Acid Hybridization
  • Pharmacogenetics
  • Genetic Association Studies
  • Cervical Cancer
  • Breast Cancer
  • Polymorphism
  • Single Nucleotide Polymorphism
  • Methotrexate
  • Carrier Proteins
Tag cloud generated 16 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

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

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

Latest Publications: RFC1 (cancer-related)

Tsubamoto H, Inoue K, Sakata K, et al.
Itraconazole Inhibits AKT/mTOR Signaling and Proliferation in Endometrial Cancer Cells.
Anticancer Res. 2017; 37(2):515-519 [PubMed] Related Publications
BACKGROUND: Itraconazole is a common antifungal agent that has demonstrated anticancer activity in preclinical and clinical studies. This study investigated whether itraconazole exerts this effect in endometrial cancer (EC) cells.
MATERIALS AND METHODS: Cell viability was evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and gene and protein expression were assessed by microarray analysis and immunoblotting, respectively, in five EC cell lines.
RESULTS: Itraconazole-suppressed proliferation of AN3-CA, HEC-1A and Ishikawa cells (p<0.05) but not of HEC-50B or SNG-II cells. Itraconazole did not suppress GLI1 or GLI2 transcription but did inhibit the expression of mammalian target of rapamycin (mTOR) signaling components in AN3-CA and HEC-1A cells, while inducing that of microtubule-associated protein 1A/1B-light chain 3-II, a marker of autophagy. ATP-binding cassette transporter A1 gene was down-regulated in Ishikawa, HEC-50B and SNG-II cells.
CONCLUSION: Itraconazole treatment suppresses the growth of EC cells by inhibiting AKT/mTOR signalling.

Johansen LL, Lock-Andersen J, Hviid TV
The Pathophysiological Impact of HLA Class Ia and HLA-G Expression and Regulatory T Cells in Malignant Melanoma: A Review.
J Immunol Res. 2016; 2016:6829283 [PubMed] Free Access to Full Article Related Publications
Malignant melanoma, a very common type of cancer, is a rapidly growing cancer of the skin with an increase in incidence among the Caucasian population. The disease is seen through all age groups and is very common in the younger age groups. Several studies have examined the risk factors and pathophysiological mechanisms of malignant melanoma, which have enlightened our understanding of the development of the disease, but we have still to fully understand the complex immunological interactions. The examination of the interaction between the human leucocyte antigen (HLA) system and prognostic outcome has shown interesting results, and a correlation between the down- or upregulation of these antigens and prognosis has been seen through many different types of cancer. In malignant melanoma, HLA class Ia has been seen to influence the effects of pharmaceutical drug treatment as well as the overall prognosis, and the HLA class Ib and regulatory T cells have been correlated with tumor progression. Although there is still no standardized immunological treatment worldwide, the interaction between the human leucocyte antigen (HLA) system and tumor progression seems to be a promising focus in the way of optimizing the treatment of malignant melanoma.

Shin J, Song IS, Pak JH, Jang SW
Upregulation of annexin A1 expression by butyrate in human melanoma cells induces invasion by inhibiting E-cadherin expression.
Tumour Biol. 2016; 37(11):14577-14584 [PubMed] Related Publications
Epithelial to mesenchymal transition (EMT) is a critical step in the metastasis of epithelial cancer cells. Butyrate, which is produced from dietary fiber by colonic bacterial fermentation, has been reported to influence EMT. However, some studies have reported that butyrate promotes EMT, while others have reported an inhibitory effect. To clarify these controversial results, it is necessary to elucidate the mechanism by which butyrate can influence EMT. In this study, we examined the potential role of annexin A1 (ANXA1), which was previously reported to promote EMT in breast cancer cells, as a mediator of EMT regulation by butyrate. We found that ANXA1 mRNA and protein were expressed in highly invasive melanoma cell lines (A2058 and A375), but not in SK-MEL-5 cells, which are less invasive. We also showed that butyrate induced ANXA1 mRNA and protein expression and promoted EMT-related cell invasion in SK-MEL-5 cells. Downregulation of ANXA1 expression using specific small interfering RNAs in butyrate-treated SK-MEL-5 cells resulted in increased expression of the epithelial marker E-cadherin and decreased cell invasion. Moreover, overexpressing ANXA1 decreased the expression of the E-cadherin. Collectively, these results indicate that butyrate induces the expression of ANXA1 in human melanoma cells, which then promotes invasion through activating the EMT signaling pathway.

Park JS, Shin S, Kim EC, et al.
Association of human papillomavirus type 16 and its genetic variants with cervical lesion in Korea.
APMIS. 2016; 124(11):950-957 [PubMed] Related Publications
Persistent human papillomavirus type 16 (HPV16) is the major risk factor for cervical cancer. HPV16 intratypic variants differ in their geographical distribution and oncogenic potential. This study aimed to analyze the distribution of HPV16 variants and their association with cervical lesion histopathology in Korean women. In total, 133 HPV16-positive cervical samples from women admitted to Seoul National University Boramae Hospital were analyzed by sequencing E6, E7, and L1 genes and the long control region (LCR), and the variant distribution according to cervical lesion grade was determined. Isolates were grouped into a phylogenetic lineage, and A1-3, A4, C, and D sublineages were detected in 54.1, 37.8, 0.7, and 7.4% of samples, respectively. The most commonly observed LCR variations were 7521G>A (91.5%), 7730A>C (59.6%), and 7842G>A (59.6%). Furthermore, A4 or D sublineage-positive women had a higher risk for cervical cancer than women who were positive for A1-3. Among HPV phylogenetic clusters, A1-3 was the predominant sublineage, and within A1-3, the 350G polymorphism was highly frequent. These results differed from those of previous studies in Korea and other Asian countries. The findings suggest that cervical neoplasia incidence in HPV16-infected patients could be affected by the distribution of HPV16 variants in the population.

Han X, Cao Y, Wang K, Zhu G
HMGA1 facilitates tumor progression through regulating Wnt/β-catenin pathway in endometrial cancer.
Biomed Pharmacother. 2016; 82:312-8 [PubMed] Related Publications
Recent studies have identified a unique role for high mobility group protein A1 (HMGA1) as a major regulator of tumor progression and in diverse tumor models. Emerging evidences indicate that overexpressed HMGA1 facilitates multiple malignant phenotypes of cancer cells, however, the oncogenic activities of HMGA1 in endometrial cancer (EC) remains elusive. Here we showed that HMGA1 was more frequently expressed in human EC tissues compared to non-tumor tissues. Elevated HMGA1 was significantly associated with advanced clinical stage. Wound-healing assay and transwell assay showed that HMGA1 can positively regulate cell migration and invasion. Mechanistically, luciferase reporter assay and Western blotting assay demonstrated that activation of Wnt/β-catenin pathway contributed to the oncogenic activity of HMGA1. Taken together, our data reveal that HMGA1 may function as an oncogene and modulate EC cell migration and invasion by activating Wnt/β-catenin pathway, implying that suppression of HMGA1 might be a potential therapeutic strategy for EC.

Zou D, Zhou Q, Wang D, et al.
The Downregulation of MicroRNA-10b and its Role in Cervical Cancer.
Oncol Res. 2016; 24(2):99-108 [PubMed] Related Publications
It has been demonstrated that microRNAs (miRNAs) act as oncogenes or tumor suppressors in a variety of cancers. Our previous work suggested that miR-10a/b functioned as a tumor suppressor in gastric cancer, and miR-10b was also reported to be significantly downregulated in advanced stage cervical cancer tissues. However, the aberrant expression of miR-10b in cervical cancer and its possible role in cervical carcinogenesis was largely unknown. In this study, we investigated the expression of miR-10b in cervical cancer tissues, carcinoma in situ tissues, mild dysplasia, moderate dysplasia, severe dysplasia tissues, and normal controls. We found that miR-10b was significantly downregulated during cervical cancer progression, and the lower level of miR-10b in cervical cancer was significantly associated with a more aggressive tumor phenotype. Moreover, overexpression of miR-10b in cervical cancer cells could inhibit the cell proliferation and invasion, and the further mechanism study suggested that its role was possibly through directly targeting HOXA1. These results suggested that the downregulation of miR-10b and the resulting elevated HOXA1 level in cervical cancer tissues might play critical roles in cervical cancer progression.

Gandhi D, Naoghare PK, Bafana A, et al.
Fluoride-Induced Oxidative and Inflammatory Stress in Osteosarcoma Cells: Does It Affect Bone Development Pathway?
Biol Trace Elem Res. 2017; 175(1):103-111 [PubMed] Related Publications
Oxidative stress is reported to negatively affect osteoblast cells. Present study reports oxidative and inflammatory signatures in fluoride-exposed human osteosarcoma (HOS) cells, and their possible association with the genes involved in osteoblastic differentiation and bone development pathways. HOS cells were challenged with sublethal concentration (8 mg/L) of sodium fluoride for 30 days and analyzed for transcriptomic expression. In total, 2632 transcripts associated with several biological processes were found to be differentially expressed. Specifically, genes involved in oxidative stress, inflammation, osteoblastic differentiation, and bone development pathways were found to be significantly altered. Variation in expression of key genes involved in the abovementioned pathways was validated through qPCR. Expression of serum amyloid A1 protein, a key regulator of stress and inflammatory pathways, was validated through western blot analysis. This study provides evidence that chronic oxidative and inflammatory stress may be associated with the fluoride-induced impediment in osteoblast differentiation and bone development.

Noh ST, Lee HS, Lim SJ, et al.
MAGE-A1-6   expression in patients with head and neck squamous cell carcinoma: impact on clinical patterns and oncologic outcomes.
Int J Clin Oncol. 2016; 21(5):875-882 [PubMed] Related Publications
BACKGROUND: Various subtypes of melanoma-associated antigens (MAGEs) are expressed in the tumor tissues of patients with head and neck squamous cell carcinoma (HNSCC). However, little data are currently available on how the gene expression of MAGEs impacts clinical patterns and oncologic outcomes. We have therefore evaluated the expression of MAGE-A1-6 (A1-6) subtypes in tumor tissues of patients with HNSCC and the clinical impact of this expression.
METHODS: This was a retrospective review of 53 patients with histologically proven HNSCC of the oral cavity, oropharynx, larynx, or hypopharynx who underwent both treatment and analysis by reverse transcription (RT)-PCR assay with a common primer to identify the expression of MAGE-A1-6 subtypes in the tumor tissue. The clinicopathologic factors and oncologic outcomes of these patients and the correlations of both to MAGE-A1-6 gene expression were analyzed.
RESULTS: MAGE-A1-6 subtypes were expressed in the tumor tissues of 37 patients (69.8 %). Patient age of ≥65 years [p = 0.031, hazard ratio (HR) 4.866] and advanced American Joint Committee on Cancer stage (p = 0.035, HR 4.291) were independent risk factors for expression of MAGE-A1-6 subtypes. Patients with MAGE-A1-6 expression had lower disease-free survival (p = 0.029), disease-specific survival (p = 0.070), and overall survival (p = 0.017) rates. Overall survival rate was independently associated to chemotherapy (p = 0.011, HR 2.859), while no surgery (p = 0.050, HR 2.400) and MAGE-A1-6 expression (p = 0.050, HR 2.527) showed borderline significance.
CONCLUSION: In our patient group the expression of MAGE-A1-6 subtypes in tumor tissues of patients with HNSCC was correlated with advanced clinical stage of cancer and poor oncologic outcomes. We suggest that gene expression of MAGE-A1-6 subtypes may be considered to be a predictive factor to determine patient treatment or follow-up strategy.

Holmes B, Lee J, Landon KA, et al.
Mechanistic Target of Rapamycin (mTOR) Inhibition Synergizes with Reduced Internal Ribosome Entry Site (IRES)-mediated Translation of Cyclin D1 and c-MYC mRNAs to Treat Glioblastoma.
J Biol Chem. 2016; 291(27):14146-59 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Our previous work has demonstrated an intrinsic mRNA-specific protein synthesis salvage pathway operative in glioblastoma (GBM) tumor cells that is resistant to mechanistic target of rapamycin (mTOR) inhibitors. The activation of this internal ribosome entry site (IRES)-dependent mRNA translation initiation pathway results in continued translation of critical transcripts involved in cell cycle progression in the face of global eIF-4E-mediated translation inhibition. Recently we identified compound 11 (C11), a small molecule capable of inhibiting c-MYC IRES translation as a consequence of blocking the interaction of a requisite c-MYC IRES trans-acting factor, heterogeneous nuclear ribonucleoprotein A1, with its IRES. Here we demonstrate that C11 also blocks cyclin D1 IRES-dependent initiation and demonstrates synergistic anti-GBM properties when combined with the mechanistic target of rapamycin kinase inhibitor PP242. The structure-activity relationship of C11 was investigated and resulted in the identification of IRES-J007, which displayed improved IRES-dependent initiation blockade and synergistic anti-GBM effects with PP242. Mechanistic studies with C11 and IRES-J007 revealed binding of the inhibitors within the UP1 fragment of heterogeneous nuclear ribonucleoprotein A1, and docking analysis suggested a small pocket within close proximity to RRM2 as the potential binding site. We further demonstrate that co-therapy with IRES-J007 and PP242 significantly reduces tumor growth of GBM xenografts in mice and that combined inhibitor treatments markedly reduce the mRNA translational state of cyclin D1 and c-MYC transcripts in these tumors. These data support the combined use of IRES-J007 and PP242 to achieve synergistic antitumor responses in GBM.

Suh M, Thompson CM, Brorby GP, et al.
Inhalation cancer risk assessment of cobalt metal.
Regul Toxicol Pharmacol. 2016; 79:74-82 [PubMed] Related Publications
Cobalt compounds (metal, salts, hard metals, oxides, and alloys) are used widely in various industrial, medical and military applications. Chronic inhalation exposure to cobalt metal and cobalt sulfate has caused lung cancer in rats and mice, as well as systemic tumors in rats. Cobalt compounds are listed as probable or possible human carcinogens by some agencies, and there is a need for quantitative cancer toxicity criteria. The U.S. Environmental Protection Agency has derived a provisional inhalation unit risk (IUR) of 0.009 per μg/m(3) based on a chronic inhalation study of soluble cobalt sulfate heptahydrate; however, a recent 2-year cancer bioassay affords the opportunity to derive IURs specifically for cobalt metal. The mechanistic data support that the carcinogenic mode of action (MOA) is likely to involve oxidative stress, and thus, non-linear/threshold mechanisms. However, the lack of a detailed MOA and use of high, toxic exposure concentrations in the bioassay (≥1.25 mg/m(3)) preclude derivation of a reference concentration (RfC) protective of cancer. Several analyses resulted in an IUR of 0.003 per μg/m(3) for cobalt metal, which is ∼3-fold less potent than the provisional IUR. Future research should focus on establishing the exposure-response for key precursor events to improve cobalt metal risk assessment.

Flodrova D, Toporova L, Macejova D, et al.
A comparative study of protein patterns of human estrogen receptor positive (MCF-7) and negative (MDA-MB-231) breast cancer cell lines.
Gen Physiol Biophys. 2016; 35(3):387-92 [PubMed] Related Publications
In the present study, we analyzed the cell lysates of human tumour cell lines representing two major clinically different types of breast cancer. Our main goal was to show the differences between them on proteomic level. Gel electrophoresis followed by MALDI-TOF MS analysis was used for proteins determination. Exactly 98 proteins were unequivocally identified and 60 of them were expressed differentially between MDA-MB-231 and MCF-7 cell lines. Among the proteins reported here, some well-known breast cancer markers (e.g., annexin A1, annexin A2 and vimentin) were identified in the MDA-MB-231 cell line and thus we were able to distinguish both cell lines sufficiently.

Hussain S, Bano R, Tahir Khan M, Haroon Khan M
Association of the CYP17-34T/C Polymorphism with Pancreatic Cancer Risk.
Asian Pac J Cancer Prev. 2016; 17(S3):71-5 [PubMed] Related Publications
Pancreatic cancer is a leading cause of fatality worldwide. Several population studies have been conducted on genetic diagnosis of pancreatic cancer but the results from epidemiologic studies are very limited. CYP17A gene has a role in disease formation but its influence on pancreatic cancer is unclear. A polymorphism in the 5'UTR promoter region of CYP17A1-34T/C (A1/A2) has been associated with multiple cancers. The aim of the current study was to assess associations of this polymorphism and socio-demographic risk factors with pancreatic cancer. A total of 255 and 320 controls were enrolled in the study, and were genetically analyzed through PCR-RFLP. Statistical analysis was conducted with observed genotype frequencies and odds ratios (ORs) and 95% CIs were estimated using unconditional logistic regression. The impact of socio-demographic factors was accessed through Kaplen-Meir analysis. According to our results, the A2/A2 genotype was significantly associated with pancreatic cancer (OR=2.1, 95%CI = 1.3-3.5). Gender female (OR=2.6, 95%CI=1.8-3.7), age group 80s/80+ years (OR=2.2, 95% CI=1.2-4), smoking both former (OR=4.6, 95% CIs=2.5-8.8) and current (OR=3.6, 95% CI=2-6.7), and family history (OR=7.1; 95%CI = 4.6-11.4) were also found associated with increased risk. Current study suggests that along with established risk factors for pancreatic cancer CYP17A1-34T/C may play a role. However, on the basis of small sample size the argument cannot be fully endorsed and larger scale studies are recommended.

Lin JF, Lin YC, Yang SC, et al.
Autophagy inhibition enhances RAD001-induced cytotoxicity in human bladder cancer cells.
Drug Des Devel Ther. 2016; 10:1501-13 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
BACKGROUND: Mammalian target of rapamycin (mTOR), involved in PI3K/AKT/mTOR pathway, is known to play a central role in regulating the growth of cancer cells. The PI3K/AKT/mTOR pathway enhances tumor survival and proliferation through suppressing autophagy, which sustains energy homeostasis by collecting and recycling cellular components under stress conditions. Conversely, inhibitors of the mTOR pathway such as RAD001 induce autophagy, leading to promotion of tumor survival and limited antitumor efficacy. We thus hypothesized that the use of autophagy inhibitor in combination with mTOR inhibition improves the cytotoxicity of mTOR inhibitors in bladder cancer.
MATERIALS AND METHODS: The cytotoxicity of RT4, 5637, HT1376, and T24 human bladder cancer cells treated with RAD001 alone or combined with autophagy inhibitors (3-methyladenine (3-MA), bafilomycin A1 (Baf A1), chloroquine, or hydroxychloroquine) was assessed using the WST-8 cell viability kit. The autophagy status in cells was analyzed by the detection of microtubule-associated light chain 3 form II (LC3-II), using immunofluorescent staining and Western blot. Acidic vesicular organelle (AVO) formation in treated cells was determined by acridine orange vital staining. Inhibition of mTOR pathway by RAD001 was monitored by using a homemade quantitative polymerase chain reaction gene array, while phospho-mTOR was detected using Western blot. Induced apoptosis was determined by measurement of caspase 3/7 activity and DNA fragmentation in cells after treatment.
RESULTS: Advanced bladder cancer cells (5637, HT1376, and T24) were more resistant to RAD001 than RT4. Autophagy flux detected by the expression of LC3-II showed RAD001-induced autophagy. AVO formation was detected in cells treated with RAD001 and was inhibited by the addition of 3-MA or Baf A1. Cotreatment of RAD001 with autophagy inhibitors further reduced cell viability and induced apoptosis in bladder cancer cells.
CONCLUSION: Our results indicate that simultaneous inhibition of the mTOR and autophagy pathway significantly enhances apoptosis, and it is suggested to be a new therapeutic paradigm for the treatment of bladder cancer.

Abdullah Al-Dhabi N, Srigopalram S, Ilavenil S, et al.
Proteomic Analysis of Stage-II Breast Cancer from Formalin-Fixed Paraffin-Embedded Tissues.
Biomed Res Int. 2016; 2016:3071013 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Breast cancer is the most frequently occurring disease among women worldwide. The early stage of breast cancer identification is the key challenge in cancer control and prevention procedures. Although gene expression profiling helps to understand the molecular mechanism of diseases or disorder in the living system, gene expression pattern alone is not sufficient to predict the exact mechanisms. Current proteomics tools hold great application for analysis of cancerous conditions. Hence, the generation of differential protein expression profiles has been optimized for breast cancer and normal tissue samples in our organization. Normal and tumor tissues were collected from 20 people from a local hospital. Proteins from the diseased and normal tissues have been investigated by 2D gel electrophoresis and MALDI-TOF-MS. The peptide mass fingerprint data were fed into various public domains like Mascot, MS-Fit, and Pept-ident against Swiss-Prot protein database and the proteins of interest were identified. Some of the differentially expressed proteins identified were human annexin, glutathione S-transferase, vimentin, enolase-1, dihydrolipoamide dehydrogenase, glutamate dehydrogenase, Cyclin A1, hormone sensitive lipase, beta catenin, and so forth. Many types of proteins were identified as fundamental steps for developing molecular markers for diagnosis of human breast cancer as well as making a new proteomic database for future research.

Dastjerdi MN, Valiani A, Mardani M, Ra MZ
Adenosine A1 receptor modifies P53 expression and apoptosis in breast cancer cell line Mcf-7.
Bratisl Lek Listy. 2016; 117(4):242-6 [PubMed] Related Publications
BACKGROUND: Breast cancer cells over-express the adenosine receptor A1 and in most of these cells, P53 gene is a wild type. Because of this finding and relationship between A1 receptor and cell apoptosis and proliferation, this study aimed to determine the effect of agonist and antagonist of A1 receptor on cell apoptosis and proliferation and recognize the relationship between this receptor and P53 expression.
METHODS: We used a Real-Time PCR test for measuring expression of p53 gene also flow cytometry assay for apoptotic and survival cell rate after treatment of MCF-7 cells with A1 receptor agonist CPA (N6-Cyclopentyladenosine) and A1 receptor antagonist DPCPX (1,3-dipropyl-8-cyclopentylxanthine) in 24,48 and 72 hours.
RESULTS: Our flow cytometry findings indicate that DPCPX significantly induces apoptosis in MCF-7. Also the expression of P53 becomes upregulated with time of DPCPX treatment. CPA treatment increased the survival cell rate and down-regulated this apoptosis-relevant gene P53 (p > 0.05).
CONCLUSION: DPCPX can induce P53 expression which consequently promotes the cell apoptosis in MCF-7. Therefore, DPCPX could be used as an anti-cancer agent (Tab. 1, Fig. 3, Ref. 5).

Miura K, Kimura K, Amano R, et al.
Establishment and characterization of new cell lines of anaplastic pancreatic cancer, which is a rare malignancy: OCUP-A1 and OCUP-A2.
BMC Cancer. 2016; 16:268 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
BACKGROUND: Anaplastic pancreatic cancer (APC) cell lines have been scarcely established.
METHODS: The morphology, gene expressions, karyotyping and epithelial-mesenchymal transition markers of newly established APC cell lines OCUP-A1 and OCUP-A2 were analyzed. Their abilities of proliferation under normoxia and hypoxia, migration and invasion were compared to 4 commercially available pancreatic ductal adenocarcinoma (PDA) cell lines. Their induction of angiogenesis, stem-like cell population and subcutaneous tumor growth in nude mice were estimated, comparing 2 PDA cell lines examined here.
RESULTS: OCUP-A1 and OCUP-A2 cells continuously grew with spindle and polygonal shapes, respectively. Gene analysis revealed 9 gene mutations including KRAS and TP53. Karyotyping clarified numerical structural abnormalities in both cells. Loss of E-cadherin and expression of vimentin in both cell lines were observed. The doubling time of both cell lines was approximately 20 h. Proliferation, migration and invasion abilities were not notable compared to other PDA cell lines. However stem-like cell population of both cell lines was superior to a part of PDA cell lines. Moreover OCUP-A1 showed stronger hypoxia tolerance and induction of angiogenesis than other PDA cell lines. The tumorigenicity in vivo of OCUP-A2 was stronger than conventional PDA cell lines.
CONCLUSIONS: The OCUP-A1 and OCUP-A2 cell lines of rare malignancies might be useful for investigating the biology of pancreatic cancer.

Li M, Zhang W, Liu C, et al.
Forkhead box A1 (FOXA1) tagging polymorphisms and esophageal cancer risk in a Chinese population: a fine-mapping study.
Biomarkers. 2016; 21(6):523-9 [PubMed] Related Publications
Esophageal cancer was the fifth most commonly diagnosed cancer and the fourth leading cause of cancer-related death in China in 2009. Esophageal squamous cell carcinoma (ESCC) accounts for more than 90% of esophageal cancers. Besides environmental risk factors, genetic factors such as single-nucleotide polymorphisms (SNPs) play an important role in ESCC carcinogenesis. We performed a hospital-based case-control study to evaluate the Forkhead-box protein A1 (FOXA1) rs12894364 C > T, rs2145146 C > A and rs7144658 T > C tag SNPs in the risk of developing ESCC. We recruited 629 ESCC cases and 686 controls. Genotypes were determined using ligation detection reaction. Logistic regression analyses revealed that the three FOXA1 SNPs were not associated with ESCC risk. However, there was significantly decreased ESCC risk associated with the FOXA1 rs12894364 C > T and rs2145146 C > A polymorphisms among older patients. There was significantly increased ESCC risk associated with the FOXA1 rs7144658 T > C polymorphism among male patients. This study demonstrates an association between FOXA1 polymorphisms and ESCC susceptibility. Additional larger studies are required to confirm our findings.

Huang J, Chen MN, Du J, et al.
Differential Expression of Adenosine P1 Receptor ADORA1 and ADORA2A Associated with Glioma Development and Tumor-Associated Epilepsy.
Neurochem Res. 2016; 41(7):1774-83 [PubMed] Related Publications
Level of adenosine, an endogenous astrocyte-based neuromodulator, is primarily regulated by adenosine P1 receptors. This study assessed expression of adenosine P1 receptors, ADORA1 (adenosine A1 receptor) and ADORA2A (adenosine A2a receptor) and their association with glioma development and epilepsy in glioma patients. Expression of ADORA1/ADORA2A was assessed immunohistochemically in 65 surgically removed glioma tissue and 21 peri-tumor tissues and 8 cases of normal brain tissues obtained from hematoma patients with cerebral trauma. Immunofluorescence, Western blot, and qRT-PCR were also used to verify immunohistochemical data. Adenosine P1 receptor ADORA1 and ADORA2A proteins were localized in the cell membrane and cytoplasm and ADORA1/ADORA2A immunoreactivity was significantly stronger in glioma and peri-tumor tissues that contained infiltrating tumor cells than in normal brain tissues (p < 0.05). The World Health Organization (WHO) grade III gliomas expressed even higher level of ADORA1 and ADORA2A. Western blot and qRT-PCR confirmed immunohistochemical data. Moreover, higher levels of ADORA1 and ADORA2A expression occurred in high-grade gliomas, in which incidence of epilepsy were lower (p < 0.05). In contrast, a lower level of ADORA1/ADORA2A expression was found in peri-tumor tissues with tumor cell presence from patients with epilepsy compared to patients without epilepsy (p < 0.05). The data from the current study indicates that dysregulation in ADORA1/ADORA2A expression was associated with glioma development, whereas low level of ADORA1/ADORA2A expression could increase susceptibility of tumor-associated epilepsy.

Fang Y, Guan X, Cai T, et al.
Knockdown of ANXA1 suppresses the biological behavior of human NSCLC cells in vitro.
Mol Med Rep. 2016; 13(5):3858-66 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Annexin A1 (ANXA1) is a member of the annexin superfamily. Previous studies have reported that ANXA1 is highly expressed in various types of malignant tumor; however, its role in the progression of non‑small cell lung cancer (NSCLC) remains to be fully clarified. The present study aimed to investigate the oncogenic role of ANXA1 in NSCLC cells in vitro. RNA interference was used to downregulate ANXA1 expression in A549 and H1299 cells using a small interfering RNA lentiviral vector. Subsequently, cell proliferation and migration were detected using Cell Counting kit‑8, clone formation, wound healing and Transwell chamber assays. Successful transfection was confirmed using fluorescence microscopy, which demonstrated that ANXA1 had been efficiently inhibited. ANXA1 knockdown suppressed the proliferation, migration and invasion of NSCLC cells. In conclusion, the present study provided evidence suggesting that ANXA1 may contribute to the growth and invasion of NSCLC cell lines, and ANXA1 may be exploited as an in vitro therapeutic target for the treatment of NSCLC.

Ke X, Zhang S, Xu J, et al.
Non-small-cell lung cancer-induced immunosuppression by increased human regulatory T cells via Foxp3 promoter demethylation.
Cancer Immunol Immunother. 2016; 65(5):587-99 [PubMed] Related Publications
Patients with non-small-cell lung cancer (NSCLC) have immune defects that are poorly understood. Forkhead box protein P3 (Foxp3) is crucial for immunosuppression by CD4(+) regulatory T cells (Tregs). It is not well known how NSCLC induces Foxp3 expression and causes immunosuppression in tumor-bearing patients. Our study found a higher percentage of CD4(+) Tregs in the peripheral blood of NSCLC compared with healthy donors. NSCLC patients showed demethylation of eight CpG sites within the Foxp3 promoter with methylation ratios negatively correlated with CD4(+)CD25(+)Foxp3(+) T levels. Foxp3 expression in CD4(+) Tregs was directly regulated by Foxp3 promoter demethylation and was involved in immunosuppression by NSCLC. To verify the effect of tumor cells on the phenotype and function of CD4(+) Tregs, we established a coculture system using NSCLC cell line and healthy CD4(+) T cells and showed that SPC-A1 induced IL-10 and TGF-β1 secretion by affecting the function of CD4(+) Tregs. The activity of DNA methyltransferases from CD4(+) T was decreased during this process. Furthermore, eight CpG sites within the Foxp3 promoter also appeared to have undergone demethylation. Foxp3 is highly expressed in CD4(+) T cells, and this may be caused by gene promoter demethylation. These induced Tregs are highly immunosuppressive and dramatically inhibit the proliferative activity of naïve CD4(+) T cells. Our study provides one possible mechanism describing Foxp3 promoter demethylation changes by which NSCLC down-regulates immune responses and contributes to tumor progression. Foxp3 represents an important target for NSCLC anti-tumor immunotherapy.

Kaffenberger SD, Barbieri CE
Molecular subtyping of prostate cancer.
Curr Opin Urol. 2016; 26(3):213-8 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
PURPOSE OF REVIEW: The recent publication of The Cancer Genome Atlas molecular taxonomy of primary prostate cancer highlights the increased understanding of the genomic basis of human prostate cancer, but also emphasizes the complexity and heterogeneity of prostate cancer.
RECENT FINDINGS: Seven molecular subclasses have been defined on the basis of early genomic alterations, which are largely mutually exclusive.
SUMMARY: We review the recent advances in the genomic understanding of human prostate cancer, with focus on molecular subclassification. Broadly, prostate cancer can be classified based upon whether specific genomic rearrangements, such as the Transmembrane Protease, Serine 2-ETS-related gene fusion occur or whether specific alterations such as Speckle-type POZ protein and forkhead box A1 mutations occur. The molecular drivers remain to be identified in a further quarter of human prostate cancers. Depending upon the molecular subclassification and the coincident genomic alterations, specific clinical insights can be gained from this information, including associations with pathologic factors, race, and prognosis, as well as the possibility for future precision therapies.

Li F, Gu C, Tian F, et al.
MiR-218 impedes IL-6-induced prostate cancer cell proliferation and invasion via suppression of LGR4 expression.
Oncol Rep. 2016; 35(5):2859-65 [PubMed] Related Publications
Prostate cancer is the most common solid-organ malignancy and the second leading cause of cancer-related death in males. The oncogenic effect of leucine-rich repeat-containing G protein-coupled receptor (LGR) 4 has been recognized in the formation of various types of cancers, yet its regulatory mechanism in prostate cancer is still not fully understood. Previous study has shown that LGR4 may be a new responsive gene of interleukin-6 (IL-6) in cancer progression. In the present study, we established the LNCaP-IL-6+ cell subline by long-term incubation with a low concentration of IL-6 and explored the regulatory role of miR-218, a tumor-suppressing miRNA, in IL-6-induced LGR4 expression and LNCaP-IL-6+ cell proliferation and invasion. The results showed that miR-218 expression was gradually decreased and IL-6 expression was gradually increased in the process of prostate cancer progression from normal prostate, benign prostatic hyperplasia to prostate cancer, and from LNCaP to LNCaP-IL-6+ cells. Notably, we also found that miR-218 inhibited the expression of cell cycle regulatory protein cyclin A1 and invasion-related matrix metalloproteinase-9 protein induced by IL-6, and impeded the accelerative effect of IL-6 on LNCaP-IL-6+ cell proliferation, cell cycle progression and cell invasion. Moreover, our results confirmed that miR-218 directly targets LGR4 and modulated the PI3K/Akt and Wnt/β-catenin pathways in the LNCaP-IL-6+ cells. Taken together, these data clearly demonstrated the involvement of the miR-218/LGR4 regulatory pathway in IL-6-induced cell proliferation and invasion in LNCaP-IL-6+ cells via PI3K/Akt and Wnt/β-catenin signaling, providing new insight into therapeutics for inflammation-induced prostate cancer.

Nishimura Y, Hyuga S, Takiguchi S, et al.
Ephedrae herba stimulates hepatocyte growth factor-induced MET endocytosis and downregulation via early/late endocytic pathways in gefitinib-resistant human lung cancer cells.
Int J Oncol. 2016; 48(5):1895-906 [PubMed] Related Publications
The MET tyrosine kinase receptor and its ligand, hepatocyte growth factor (HGF), are known to be overexpressed in a variety of malignant tumor cells, and are implicated in the development of gefitinib-resistance in human non-small cell lung cancer (NSCLC) cells. Ephedrae herba was previously reported to prevent HGF-induced cancer cell motility by directly suppressing HGF/MET signaling through the inhibition of MET tyrosine kinase, and treatment with its extract also considerably reduced MET protein levels. To further investigate the mechanism underlying the Ephedrae herba-induced inhibition of MET phosphorylation as well as its degradation and subsequent disappearance, we examined the effect of Ephedrae herba on HGF-stimulated MET endocytosis and downregulation via early/late endocytic pathways in an NSCLC cell line. Using immunofluorescence microscopy, we found that pretreatment of cells with Ephedrae herba extract dramatically changed the intracellular distribution of plasma membrane-associated MET, and that the resultant MET staining was distributed throughout the cytoplasm. Pretreatment of the cells with Ephedrae herba extract also led to the rapid loss of MET and phosphorylated (p)-MET in HGF-stimulated cells. In contrast, inefficient endocytic delivery of MET and p-MET from early to late endosomes was observed in the absence of Ephedrae herba extract, since considerable amounts of the internalized MET accumulated in the early endosomes and were not delivered to lysosomes up to 1 h after HGF-stimulation. Furthermore, large amounts of MET and p-MET that had accumulated in late endosomes of Ephedrae herba-pretreated cells after HGF stimulation were observed along with bafilomycin A1. Therefore, we inferred that degradation of MET occurred in the late endosome/lysosome pathway. Moreover, western blot analysis revealed the accelerated degradation of MET and p-MET proceeds in cells pretreated with Ephedrae herba extract. Collectively, our results suggest that some components of Ephedrae herba have a novel role in promoting HGF-stimulated MET and p-MET endocytosis followed by its downregulation, likely mediated by the early/late endocytic pathways.

Sumter TF, Xian L, Huso T, et al.
The High Mobility Group A1 (HMGA1) Transcriptome in Cancer and Development.
Curr Mol Med. 2016; 16(4):353-93 [PubMed] Related Publications
BACKGROUND & OBJECTIVES: Chromatin structure is the single most important feature that distinguishes a cancer cell from a normal cell histologically. Chromatin remodeling proteins regulate chromatin structure and high mobility group A (HMGA1) proteins are among the most abundant, nonhistone chromatin remodeling proteins found in cancer cells. These proteins include HMGA1a/HMGA1b isoforms, which result from alternatively spliced mRNA. The HMGA1 gene is overexpressed in cancer and high levels portend a poor prognosis in diverse tumors. HMGA1 is also highly expressed during embryogenesis and postnatally in adult stem cells. Overexpression of HMGA1 drives neoplastic transformation in cultured cells, while inhibiting HMGA1 blocks oncogenic and cancer stem cell properties. Hmga1 transgenic mice succumb to aggressive tumors, demonstrating that dysregulated expression of HMGA1 causes cancer in vivo. HMGA1 is also required for reprogramming somatic cells into induced pluripotent stem cells. HMGA1 proteins function as ancillary transcription factors that bend chromatin and recruit other transcription factors to DNA. They induce oncogenic transformation by activating or repressing specific genes involved in this process and an HMGA1 "transcriptome" is emerging. Although prior studies reveal potent oncogenic properties of HMGA1, we are only beginning to understand the molecular mechanisms through which HMGA1 functions. In this review, we summarize the list of putative downstream transcriptional targets regulated by HMGA1. We also briefly discuss studies linking HMGA1 to Alzheimer's disease and type-2 diabetes.
CONCLUSION: Further elucidation of HMGA1 function should lead to novel therapeutic strategies for cancer and possibly for other diseases associated with aberrant HMGA1 expression.

Wu BO, Jiang WG, Zhou D, Cui YX
Knockdown of EPHA1 by CRISPR/CAS9 Promotes Adhesion and Motility of HRT18 Colorectal Carcinoma Cells.
Anticancer Res. 2016; 36(3):1211-9 [PubMed] Related Publications
BACKGROUND: Erythropoietin-producing hepatocellular A1 (EPHA1) is the first member of the EPH superfamily. Its abnormal expression has been reported in various cancer types. However, the contribution of EPHA1 to the regulation of colorectal cancer cell behaviour remains unknown.
MATERIALS AND METHODS: In this study, we investigated the expression profile of EPHA1 in human colorectal cancer and its effect on the adhesion and motility of colorectal cancer cells. We used human colorectal cancer specimens and the colorectal adenocarcinoma cell line HRT18 for this purpose.
RESULTS: Our cohort screening data showed that in patients with colorectal cancer, low expression of EPHA1 gene is correlated with a remarkably reduced survival. After EPHA1 is knocked-down in colorectal cancer cells using a clustered regularly interspaced short palindromic repeats-associated nuclease 9 (CRISPR-CAS9) genomic editing system, we observed an increase in the spreading and adhesion of HRT18 cells. Moreover, protein array data indicated that the extracellular-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) signaling pathways were activated as a consequence. Inhibition of ERK and JNK proteins with specific inhibitors led to suppression of migration of the colorectal cancer cells.
CONCLUSION: EPHA1 suppresses spreading and adhesion of HRT18 colorectal cancer cells through deactivation of ERK and JNK signaling pathways.

Sorber R, Teper Y, Abisoye-Ogunniyan A, et al.
Whole Genome Sequencing of Newly Established Pancreatic Cancer Lines Identifies Novel Somatic Mutation (c.2587G>A) in Axon Guidance Receptor Plexin A1 as Enhancer of Proliferation and Invasion.
PLoS One. 2016; 11(3):e0149833 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
The genetic profile of human pancreatic cancers harbors considerable heterogeneity, which suggests a possible explanation for the pronounced inefficacy of single therapies in this disease. This observation has led to a belief that custom therapies based on individual tumor profiles are necessary to more effectively treat pancreatic cancer. It has recently been discovered that axon guidance genes are affected by somatic structural variants in up to 25% of human pancreatic cancers. Thus far, however, some of these mutations have only been correlated to survival probability and no function has been assigned to these observed axon guidance gene mutations in pancreatic cancer. In this study we established three novel pancreatic cancer cell lines and performed whole genome sequencing to discover novel mutations in axon guidance genes that may contribute to the cancer phenotype of these cells. We discovered, among other novel somatic variants in axon guidance pathway genes, a novel mutation in the PLXNA1 receptor (c.2587G>A) in newly established cell line SB.06 that mediates oncogenic cues of increased invasion and proliferation in SB.06 cells and increased invasion in 293T cells upon stimulation with the receptor's natural ligand semaphorin 3A compared to wild type PLXNA1 cells. Mutant PLXNA1 signaling was associated with increased Rho-GTPase and p42/p44 MAPK signaling activity and cytoskeletal expansion, but not changes in E-cadherin, vimentin, or metalloproteinase 9 expression levels. Pharmacologic inhibition of the Rho-GTPase family member CDC42 selectively abrogated PLXNA1 c.2587G>A-mediated increased invasion. These findings provide in-vitro confirmation that somatic mutations in axon guidance genes can provide oncogenic gain-of-function signals and may contribute to pancreatic cancer progression.

Wu Q, Jiang Y, Cui S, et al.
The role of cofilin-l in vulvar squamous cell carcinoma: A marker of carcinogenesis, progression and targeted therapy.
Oncol Rep. 2016; 35(5):2743-54 [PubMed] Related Publications
Numerous studies have revealed that cofilin-l (CFL1) is associated with cancer cell migration and invasion in various types of tumor tissues. We investigated the roles of CFL1 in vulvar squamous cell carcinoma (VSCC). CFL1 expression was detected in VSCC and normal vulvar tissues using immunohistochemistry and western blotting. The vulvar carcinoma SW962 cell line was transfected with CFL1 small interfering RNA (siRNA) and exposed to periplocoside. We then assessed changes in cell proliferation, apoptosis, invasion and metastasis. We detected changes in CFL1 mRNA and protein expression by RT-PCR and western blotting, and alterations in protein expression of various relevant molecules by western blotting. CFL1 expression was found to be significantly upregulated in the VSCC tissues compared with the normal vulvar tissues by immunohistochemistry and western blotting (P<0.05) and was positively correlated with International Federation of Gynecology and Obstetrics (FIGO) stage, differentiation and lymphatic metastasis (P<0.05). After CFL1 knockdown by siRNA transfection, SW962 cells exhibited a decrease in growth, G1 phase cell cycle arrest, induction of apoptotic, low invasion and metastasis, and disrupted lamellipodium formation. We found that the protein expression of Bcl-xL, cyclin A1, MMP2, MMP9 and STAT3 was decreased, while expression of Bax was increased. Periplocoside inhibited SW962 cell growth, promoted apoptosis, suppressed invasion and migration, and lamellipodium formation. Periplocoside exposure resulted in lower CFL1, Bcl-xL, cyclin A1, MMP2, MMP9 and STAT3 levels, but a higher Bax level compared with the control group. We demonstrated that abnormal CFL1 expression may affect vulvar carcinogenesis and subsequent progression. CFL1 silencing by siRNA significantly inhibited VSCC cell progression, which suggests that CFL1 is a potential therapeutic target for vulvar cancer. Periplocoside, which was utilized in the present study for the clinical treatment of vulvar cancer, showed strong antitumor effects by suppression of CFL1 expression.

He W, Ye X, Huang X, et al.
Hsp90 inhibitor, BIIB021, induces apoptosis and autophagy by regulating mTOR-Ulk1 pathway in imatinib-sensitive and -resistant chronic myeloid leukemia cells.
Int J Oncol. 2016; 48(4):1710-20 [PubMed] Related Publications
Development of drug resistance due to BCR-ABL point mutations and the persistence of leukemia initiating cells has become a major obstacle for tyrosine kinase inhibitors (TKIs) in the treatment of chronic myeloid leukemia (CML). The BCR-ABL protein is an important client protein of heat shock protein 90 (Hsp90). BIIB021, an orally available Hsp90 inhibitor, has activity against various cancer cells. However, little is known about the inhibitory effect of BIIB021 on CML cells. We evaluated the inhibitory effects of BIIB021 on K562, K562/G (an imatinib-resistant cell lines), as well as 32D mouse leukemic cells expressing wild-type BCR-ABL (b3a2, 32Dp210) and T315I mutant BCR-ABL (32Dp210-T315I) cells. Our data showed that BIIB021 induced significant growth inhibition and apoptosis that was predominantly mediated by the mitochondrial pathway. BIIB021 also resulted in proteasomal degradation of BCR-ABL proteins. In addition to induction of apoptosis, we report for the first time that BIIB021 induced autophagic response as evidenced by the formation of autophagosome, increased conversion of microtubule-associated protein light chain 3 (LC3)-I to LC3-II, decreased p62 (SQSTM1) protein levels. Further study suggested that Akt-mTOR-Ulk1 signaling pathway was involved in BIIB021-triggered autophagy. Moreover, blocking autophagy using pharmacological inhibitor 3-methyladenine and bafilomycin A1 significantly enhanced cell death and apoptosis induced by BIIB021, indicating the cytoprotective role of autophagy in BIIB021-treated CML cells. Collectively, these data provide possible molecular mechanisms for the antileukemic effect of BIIB021 on imatinib-sensitive and -resistant CML cells and provide new insights into the future application of BIIB021 in the clinical treatment of CML.

Jung HJ, Seo I, Casciello F, et al.
The anticancer effect of chaetocin is enhanced by inhibition of autophagy.
Cell Death Dis. 2016; 7:e2098 [PubMed] Related Publications
Chaetocin is a fungal metabolite that possesses a potent antiproliferative activity in solid tumors by inducing cell death. Although recent studies have extended the role of chaetocin in tumors, the underlying molecular mechanisms such as the downstream cascade that induces cell death has not clearly been elucidated. In this study, we show that chaetocin is able to induce both apoptosis and autophagy in several hepatoma cell lines including HepG2, Hep3B and Huh7 cell lines. Moreover, we found that the inhibition of caspase-3/7 activity by z-VAD-fmk treatment was able to block chaetocin-mediated cell death, whereas blocking autophagy by Bafilomycin A1 or the knockdown of autophagy protein 5 enhanced cell death mediated by chaetocin. These findings suggest that chaetocin has a potent anticancer effect against hepatoma. Inhibition of autophagy may potentiate anticancer effects of chaetocin thus providing evidence that combined treatment with chaetocin and autophagy inhibitors will be an effective strategy for treating cancer.

Palumbo C, De Luca A, Rosato N, et al.
c-Jun N-terminal kinase activation by nitrobenzoxadiazoles leads to late-stage autophagy inhibition.
J Transl Med. 2016; 14:37 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
BACKGROUND: Nitrobenzoxadiazole derivatives (NBDs), including NBDHEX and the recently developed MC3181, are promising anticancer agents able to target glutathione transferase and inhibit both its catalytic activity and ability to sequester TNF-receptor associated factor 2 (TRAF2) and c-Jun N-terminal kinase (JNK). NBDs have been shown to impair the growth and survival of a broad-spectrum of tumor types, in vitro and in vivo. Herein, we evaluated the effects of the new compound MC3181 on U-2OS osteosarcoma cells and investigated the impact of both NBDHEX and MC3181 on autophagy.
METHODS: Cell viability was evaluated by sulforhodamine B assay. The dissociation of the TRAF2-GSTP1-1 complex was detected by proximity ligation assay, while the phospho-activation of JNK was assessed by western blotting. The effects of NBDs on autophagy were evaluated by GFP-LC3 puncta formation, western blotting for LC3-II and p62, and LC3 turnover assay in the presence of bafilomycin A1. The role of JNK in the reduction of autophagic flux caused by NBDs was investigated using JNK1 shRNA-transfected cells. Fluorogenic caspase activity assay and flow cytometric analysis of DNA content were used to determine the cytotoxic effects of NBDs on JNK1-silenced cells.
RESULTS: Similar to NBDHEX, MC3181 reduced viability and activated TRAF2/JNK signaling in U-2OS cells. Moreover, NBDs induced the accumulation of autophagic vesicles and LC3-II while reducing both basal and nutritional stress-induced autophagic flux. Furthermore, increased levels of both LC3-II and the autophagy selective substrate p62 were observed in different tumor cell lines treated with NBDs, the concurrent increase of these markers being consistent with an impairment of autophagosome clearance. Autophagy inhibition by NBDs required JNK activity: NBDs caused autophagy inhibition and caspase-3 activation in JNK-positive U-2OS, but no autophagic flux inhibition or caspase-3 activation in JNK-silenced cells.
CONCLUSIONS: Our demonstration that NBDs can act as late-phase autophagy inhibitors opens new opportunities to fully exploit their therapeutic potential. This may not rely solely on their effectiveness in inducing cell cycle arrest and apoptosis, but also on their ability to weaken the capacity of tumor cells to endure stress conditions via autophagy. In addition, this study provides evidence that JNK can participate in impairing autophagy.

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