Gene Summary

Gene:CTSL; cathepsin L
Aliases: MEP, CATL, CTSL1
Summary:The protein encoded by this gene is a lysosomal cysteine proteinase that plays a major role in intracellular protein catabolism. Its substrates include collagen and elastin, as well as alpha-1 protease inhibitor, a major controlling element of neutrophil elastase activity. The encoded protein has been implicated in several pathologic processes, including myofibril necrosis in myopathies and in myocardial ischemia, and in the renal tubular response to proteinuria. This protein, which is a member of the peptidase C1 family, is a dimer composed of disulfide-linked heavy and light chains, both produced from a single protein precursor. Multiple alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Apr 2012]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:cathepsin L1
Source:NCBIAccessed: 07 August, 2015


What does this gene/protein do?
Show (16)
Pathways:What pathways are this gene/protein implicaed in?
Show (1)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 07 August 2015 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.

  • Apoptosis
  • Up-Regulation
  • Chromosome 9
  • Cell Line
  • Gene Expression Profiling
  • Cathepsins
  • Rats, Inbred F344
  • Enzyme Activation
  • Ovarian Cancer
  • Mice, Transgenic
  • Intracellular Signaling Peptides and Proteins
  • Cancer Gene Expression Regulation
  • Genomics
  • Tumor Stem Cell Assay
  • DNA Methylation
  • Adolescents
  • Cell Movement
  • Cathepsin B
  • Reproducibility of Results
  • Thyroid Cancer
  • Transcription Factors
  • Oligonucleotide Array Sequence Analysis
  • Young Adult
  • Cervical Cancer
  • Leukemic Gene Expression Regulation
  • p53 Protein
  • Cystatin C
  • Immunohistochemistry
  • Virus Assembly
  • Tumor Suppressor Proteins
  • Fibroblasts
  • Neoplastic Cell Transformation
  • Melanoma
  • Cysteine Endopeptidases
  • Transfection
  • Breast Cancer
  • Urokinase-Type Plasminogen Activator
  • Matrix Metalloproteinases
  • Osteosarcoma
  • Cathepsin L
  • Tumor Markers
  • Esophageal Cancer
Tag cloud generated 07 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

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: CTSL (cancer-related)

Ruan J, Zheng H, Fu W, et al.
Increased expression of cathepsin L: a novel independent prognostic marker of worse outcome in hepatocellular carcinoma patients.
PLoS One. 2014; 9(11):e112136 [PubMed] Free Access to Full Article Related Publications
OBJECTIVES: To investigate the expression and role of Cathepsin L (CTSL) in Hepatocellular carcinoma (HCC) tissue and cell line (MHCC-97H), and to evaluate the clinical and prognostic significance of CTSL protein in patients with HCC.
METHODS: The expression of CTSL was examined in HCC tissue and MHCC-97H cells by Western-blotting, Real-time PCR and immunohistochemical staining. Cell growth curve assay and colony formation assay were used to verify the effect of CTSL on the proliferation and tumor progression ability of MHCC-97H cells. Tumor formation assay in nude mice was used to analyze the effect of CTSL on the tumorigenicity of MHCC-97H cells.
RESULTS: The status of CTSL protein in carcinoma tissues is much higher than that in paracarcinoma tissues. The overall survival of the patients with high CTSL expression was significantly shorter than the low CTSL expression group. high CTSL expression was significantly correlated with advanced clinical staging, histological grade and tumor recurrence. In vitro experiments demonstrated that over-expression of CTSL in MHCC-97H cells promoted cell proliferation and tumor progression ability. Down-regulation of CTSL showed the opposite effects. Over-expression of CTSL increase the tumorigenicity of MHCC-97H cells by in vivo experiments. Moreover, multivariate analysis suggested that CTSL expression might be an independent prognostic indicator for the survival of HCC patients after curative surgery.
CONCLUSIONS: CTSL might involve in the development and progression of HCC as a oncogene, and thereby may be a valuable prognostic marker for HCC patients.

Mariş D, Nica D, Mohan D, et al.
Multidisciplinary management of adult low grade gliomas.
Chirurgia (Bucur). 2014 Sep-Oct; 109(5):590-9 [PubMed] Related Publications
BACKGROUND: Adult hemispheric low grade gliomas (LGG) cover a pathologic spectrum which has specific clinical, histological and molecular characteristics. The optimal management of these tumors is still a controversial topic in international literature.
METHODS: We evaluated scientific papers from the literature (Medline and Cochrane Library to date) and we compared the results found there with our experience, trying to create a pattern of treatment of our own.
RESULTS AND CONCLUSIONS: The advances in microsurgical and neuromonitoring techniques, as well as in neuroimaging, allow for a more aggressive resection of LGG with a significant improvement in overall survival and quality of life. The potential risks of the "wait and see" policy and the neurotoxicity of radiotherapy are challenged by the benefits of careful surgical resection and up-front chemotherapy. The present day treatment strategy, based on recent evidence, should include a maximal surgical resection when possible, with the full preservation of the patients ability, and delayed radiotherapy. The role of temozolomide in the management of LGG and the identification of the therapeutic modality with the best quality of life profile will be determined by ongoing trials. The further characterization of prognostic relevance of molecular markers and data from advanced imaging techniques needs an intensification of research and validation efforts.
ABBREVIATIONS: LGG: low grade gliomas, WHO: World Health Organization, OS: overall survival, PFS: progression-free survival, MRI: Magnetic resonance imaging, MRS: Magnetic resonance spectroscopy, MPFS: malignant progression-free survival, rCBV: Relative Cerebral Blood Volume, QOL: quality of life, FLAIR: Fluid attenuated inversion recovery, MGMT: O6-methylguanine DNA methyltransferase enzyme, DSC MR imaging: Dynamic Susceptibility Contrast Perfusion MR imaging, 1H-MRS: Proton Magnetic Resonance Spectroscopy, IDH1: isocitrate dehydrogenase 1 gene, SPECT: Single-photon emission computed tomography, PET: Positron emission tomography, DTI-FT: Diffuse Tensor Imaging-fiber tracking technique, DES: direct electrical stimulation, EEG: Electroencephalography, EcoG: Electrocorticography, MEP: motor evoked potentials, EMG: Electromyography, AED: anti-epileptic drugs, TMZ: Temozolomide, EORTC: European Organization for Research and Treatment of Cancer, NCCTG: North Central Cancer Treatment Group, RTOG: Radiation Therapy Oncology Group, ECOG: Eastern Cooperative Oncology Group, EOR: extent of resection, Gy: Gray (unit), GyE: gray equivalent, RT: radiation therapy, IMRT: image-guided intensity modulated radiotherapy, FSRT: fractionated stereotactic radiotherapy, SRS: proton therapy or stereotactic radiosurgery, LET: high-linear energy transfer beams, RBE: relative biological effectiveness, CTCAE: Common Terminology Criteria for Adverse Events, PCV: procarbazine, lomustine, and vincristine chemotherapy.

Zhang L, Wei L, Shen G, et al.
Cathepsin L is involved in proliferation and invasion of ovarian cancer cells.
Mol Med Rep. 2015; 11(1):468-74 [PubMed] Related Publications
Cathepsin L (CTSL) is a lysosomal cysteine protease that has been found to be overexpressed in ovarian cancer (OC). The aim of the present study was to investigate the possible involvement of CTSL in the development of OC. In this study, RNA interference with a CTSL small hairpin RNA (CTSL-shRNA), and a plasmid carrying CTSL were used to identify the effects of this enzyme on the regulation of the malignant behavior of OC cells. OV-90 and SKOV3 human ovarian cancer cell lines were selected as cell models in vitro and in vivo. The results showed that downregulation of CTSL significantly inhibits the proliferative and invasive capability of SKOV3 cells, and that upregulation of CTSL in OV-90 cells leads to opposite effects. Compared with parental OC cells, cells in which CTSL was silenced exhibited a reduced capacity to develop into tumors in nude mice, while the growth of tumor xenografts derived from these cells was markedly constrained. In conclusion, the results suggested that CTSL contributes to the proliferation and metastasis of OC, and that CTSL may be a novel molecular target for OC treatment.

Skinner HD, Lee JH, Bhutani MS, et al.
A validated miRNA profile predicts response to therapy in esophageal adenocarcinoma.
Cancer. 2014; 120(23):3635-41 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: In the current study we present a validated miRNA signature to predict pathologic complete response (pCR) to neoadjuvant chemoradiation in esophageal adenocarcinoma.
METHODS: Three patient cohorts (discovery, n = 10; model, n = 43; and validation, n = 65) with locally advanced esophageal adenocarcinoma were analyzed. In the discovery cohort 754 miRNAs were examined in pretreatment tumor biopsy specimens using a TaqMan array. Of these, the 44 most significantly altered between tumors with pCR and non-pCR were examined in an additional 43 tumors using a Fluidigm 48.48 array. The 4 miRNAs (mir-505*, mir-99b, mir-451, and mir-145*) significantly predicting pCR in both cohorts were examined in an additional validation cohort (n = 65) using an Illumina array. These 4 miRNAs were used to generate an miRNA expression profile (MEP) score.
RESULTS: The 4 miRNAs profiled are highly significantly associated with pCR in the model cohort (Ptrend  = .008), the validation cohort (Ptrend  = .025), and the combined cohort (Ptrend  = 4.6 × 10(-4) ). The receiver-operator characteristic areas under the curves (AUCs) for the MEP score were 0.78 for the model cohort, 0.71 for the validation cohort, and 0.72 for the combined cohort. When combined with clinical variables, the MEP score AUCs increased to 0.89, 0.77, and 0.81, respectively Estimates from logistic regression based on the MEP were determined and used to generate a probability of pCR plot, which identifies a group of patients with very high (≥80%) and very low (≤10%) probability of pCR.
CONCLUSIONS: The MEP score provides a validated means of predicting pCR to neoadjuvant chemoradiotherapy in esophageal adenocarcinoma that is robust across several analysis platforms.

Huang PC, Li WF, Liao PC, et al.
Risk for estrogen-dependent diseases in relation to phthalate exposure and polymorphisms of CYP17A1 and estrogen receptor genes.
Environ Sci Pollut Res Int. 2014; 21(24):13964-73 [PubMed] Related Publications
Evidence has shown that polymorphisms of various genes known to be involved in estrogen biosynthesis and function are associated with estrogen-dependent diseases (EDDs). These genes include CYP17A1, estrogen receptor 1 (ESR1), and 2 (ESR2). Phthalates are considered estrogenic endocrine disruptors, and recent research has suggested that they may act as a risk factor for EDDs. However, extremely few studies have assessed the effects of gene-environment interaction on these diseases. We recruited 44 patients with endometriosis or adenomyosis, 36 patients with leiomyoma, and 69 healthy controls from a medical center in Taiwan between 2005 and 2007. Urine samples were collected and analyzed for seven phthalate metabolites using liquid chromatography tandem mass spectrometry. Peripheral lymphocytes were used for DNA extraction to determine the genotype of CYP17A1, ESR1, and ESR2. Compared to controls, patients with leiomyoma had significantly higher levels of total urinary mono-ethylhexyl phthalate (ΣMEHP) (52.1 vs. 29.6 μg/g creatinine, p = 0.040), mono-n-butyl phthalate (MnBP) (75.4 vs. 51.3 μg/g creatinine, p = 0.019), and monoethyl phthalate (MEP) (103.7 vs. 59.3 μg/g creatinine, p = 0.031). In contrast, patients with endometriosis or adenomyosis showed a marginally increased level of urinary MEHP only. Subjects who were homozygous for both the ESR1 C allele (rs2234693) and CYP17A1 C allele (rs743572) showed a significantly increased risk for leiomyoma (OR = 19.8; 95 % CI, 1.70; 231.5; p = 0.017) relative to subjects with other genotypes of ESR1 and CYP17A1. These results were obtained after adjusting for age, cigarette smoking, MEHP level, GSTM1 genotype and other covariates. Our results suggested that both CYP17A1 and ESR1 polymorphisms may modulate the effects of phthalate exposure on the development of leiomyoma.

Subimerb C, Wongkham C, Khuntikeo N, et al.
Transcriptional profiles of peripheral blood leukocytes identify patients with cholangiocarcinoma and predict outcome.
Asian Pac J Cancer Prev. 2014; 15(10):4217-24 [PubMed] Related Publications
Cholangiocarcinoma (CCA), a slow growing but highly metastatic tumor, is highly prevalent in Northeast Thailand. Specific tests that predict prognosis of CCA remain elusive. The present study was designed to investigate whether peripheral blood leukocyte (PBL) transcriptional profiles might be of use as a prognostic test in CCA patients. Gene expression profiles of PBLs from 9 CCA and 8 healthy subjects were conducted using the Affymetrix HG_U133 Plus 2.0 GeneChip. We indentified informative PBLs gene expression profiles that could reliably distinguish CCA patients from healthy subjects. Of these CCA specific genes, 117 genes were up regulated and 60 were down regulated. The molecular and cellular functions predicted for these CCA specific genes according to the Gene Ontology database indicated differential PBL expression of host immune response and tumor progression genes (EREG, TGF β1, CXCL2, CXCL3, IL-8, and VEGFA). The expression levels of 9 differentially expressed genes were verified in 36 CCA vs 20 healthy subjects. A set of three tumor invasion related genes (PLAU, CTSL and SERPINB2) computed as "prognostic index" was found to be an independent and statistically significant predictor for CCA patient survival. The present study shows that CCA PBLs may serve as disease predictive clinically accessible surrogates for indentifying expressed genes reflective of CCA disease severity.

Gong J, Zhang H, Xing S, et al.
High expression levels of CXCL12 and CXCR4 predict recurrence of adamanti-nomatous craniopharyngiomas in children.
Cancer Biomark. 2014; 14(4):241-51 [PubMed] Related Publications
BACKGROUND: Adamantinomatous craniopharyngioma (ACP) is a benign but maldevelopmental tumor with a high recurrence rate.
OBJECTIVE: Theaim of this study was to investigate the dysregulated biological molecules that play important roles in the recurrence of ACP.
METHODS: We first performed microarray analysis on tumor samples from two pediatric patients with recurrent ACP and from two pediatric ACP patients without recurrence after a one-year follow-up. The expression of CXCL12 and CXCR4 in 45 specimens of pediatric ACP was further evaluated by immunohistochemistry. These results were correlated with the clinicopathological parameters and survival of the patients.
RESULTS: Four downregulated genes (APC, ITGA, MCAM, and TIMP4) and 16 upregulated genes (CST7, CTSK, CTSL1, CXCL12, CXCR4, FN1, FXYD5, ITGB3, MMP2, MMP3, MMP7, MMP9, NR4A3, PLAUR, TIMP2, and VEGFA) were found in the recurrent patients. CXCL12 and CXCR4 were highly expressed in 13 patients (28.9%) and 14 patients (31.1%), respectively. High levels of CXCL12 and CXCR4 expression were significantly associated with a poor recurrence-free survival and were the prognostic factors for ACP recurrence in pediatric patients.
CONCLUSIONS: High levels of CXCL12 and CXCR4 expression were associated with ACP recurrence. The role of CXCL12 and CXCR4 in the development of brain tumors requires further research.

Dautzenberg IJ, van den Wollenberg DJ, van den Hengel SK, et al.
Mammalian orthoreovirus T3D infects U-118 MG cell spheroids independent of junction adhesion molecule-A.
Gene Ther. 2014; 21(6):609-17 [PubMed] Related Publications
In the canonical pathway, infection of cells by the wild-type mammalian orthoreovirus Type 3 Dearing (T3D) is dependent on the interaction of the viral spike protein σ1 with the high-affinity cellular receptor junction adhesion molecule-A (JAM-A). We previously demonstrated that the human glioblastoma cell line U-118 MG does not express JAM-A and resists reovirus T3D infection in standard cell culture conditions (SCCC). Heterologous JAM-A expression sensitises U-118 MG cells to reovirus T3D. Here we studied reovirus infection in U-118 MG cells grown in spheroid cultures with the premise that cells in such cultures resemble cells in tumours more than those grown under standard adherent cell culture conditions on a plastic surface. Although the U-118 MG cells in spheroids do not express JAM-A, they are susceptible to reovirus T3D infection. We show that this can be attributed to factors secreted by cells in the spheroids. The concentration of active extracellular proteases cathepsin B and L in the medium of spheroid cultures was increased 19- and 24-fold, respectively, as compared with SCCC. These enzymes can convert the reovirus particles into a form that can infect the U-118 MG cells independent of JAM-A. Taken together, these data demonstrate that infection of tumour cells by wild-type reovirus T3D is not strictly dependent on the expression of JAM-A on the cell surface.

Ueki N, Lee S, Sampson NS, Hayman MJ
Selective cancer targeting with prodrugs activated by histone deacetylases and a tumour-associated protease.
Nat Commun. 2013; 4:2735 [PubMed] Related Publications
Eradication of cancer cells while minimizing damage to healthy cells is a primary goal of cancer therapy. Highly selective drugs are urgently needed. Here we demonstrate a new prodrug strategy for selective cancer therapy that utilizes increased histone deacetylase (HDAC) and tumour-associated protease activities produced in malignant cancer cells. By coupling an acetylated lysine group to puromycin, a masked cytotoxic agent is created, which is serially activated by HDAC and an endogenous protease cathepsin L (CTSL) that remove the acetyl group first and then the unacetylated lysine group liberating puromycin. The agent selectively kills human cancer cell lines with high HDAC and CTSL activities. In vivo studies confirm tumour growth inhibition in prodrug-treated mice bearing human cancer xenografts. This cancer-selective cleavage of the masking group is a promising strategy for the next generation of anticancer drug development that could be applied to many other cytotoxic agents.

Qiao S, Tao S, Rojo de la Vega M, et al.
The antimalarial amodiaquine causes autophagic-lysosomal and proliferative blockade sensitizing human melanoma cells to starvation- and chemotherapy-induced cell death.
Autophagy. 2013; 9(12):2087-102 [PubMed] Free Access to Full Article Related Publications
Pharmacological inhibition of autophagic-lysosomal function has recently emerged as a promising strategy for chemotherapeutic intervention targeting cancer cells. Repurposing approved and abandoned non-oncological drugs is an alternative approach to the identification and development of anticancer therapeutics, and antimalarials that target autophagic-lysosomal functions have recently attracted considerable attention as candidates for oncological repurposing. Since cumulative research suggests that dependence on autophagy represents a specific vulnerability of malignant melanoma cells, we screened a focused compound library of antimalarials for antimelanoma activity. Here we report for the first time that amodiaquine (AQ), a clinical 4-aminoquinoline antimalarial with unexplored cancer-directed chemotherapeutic potential, causes autophagic-lysosomal and proliferative blockade in melanoma cells that surpasses that of its parent compound chloroquine. Monitoring an established set of protein markers (LAMP1, LC3-II, SQSTM1) and cell ultrastructural changes detected by electron microscopy, we observed that AQ treatment caused autophagic-lysosomal blockade in malignant A375 melanoma cells, a finding substantiated by detection of rapid inactivation of lysosomal cathepsins (CTSB, CTSL, CTSD). AQ-treatment was associated with early induction of energy crisis (ATP depletion) and sensitized melanoma cells to either starvation- or chemotherapeutic agent-induced cell death. AQ displayed potent antiproliferative effects, and gene expression array analysis revealed changes at the mRNA (CDKN1A, E2F1) and protein level (TP53, CDKN1A, CCND1, phospho-RB1 [Ser 780]/[Ser 807/811], E2F1) consistent with the observed proliferative blockade in S-phase. Taken together, our data suggest that the clinical antimalarial AQ is a promising candidate for repurposing efforts that aim at targeting autophagic-lysosomal function and proliferative control in malignant melanoma cells.

Primon M, Huszthy PC, Motaln H, et al.
Cathepsin L silencing enhances arsenic trioxide mediated in vitro cytotoxicity and apoptosis in glioblastoma U87MG spheroids.
Exp Cell Res. 2013; 319(17):2637-48 [PubMed] Related Publications
Despite improved treatment options, glioblastoma multiforme (GBM) remains the most aggressive brain tumour with the shortest post-diagnostic survival. Arsenite (As2O3) is already being used in the treatment of acute promyelocytic leukaemia (APL), yet its effects on GBM have not been evaluated in detail. In U87MG cell monolayers, we have previously shown that arsenite cytotoxicity significantly increases upon transient inhibition of lysosomal protease Cathepsin L (CatL). As multicellular spheroids more closely represent in vivo tumours, we aimed to evaluate the impact of permanent CatL silencing on arsenite treatment in U87MG spheroids. CatL was stably silenced using shRNA expression plasmid packed lentiviruses. By using metabolic- and cell viability assays, we demonstrated that long-term CatL silencing significantly increased arsenite cytotoxicity in U87MG spheroids. Silenced CatL also increased arsenite-mediated apoptosis in spheroids via elevated p53 expression, Bax/Bcl2 ratio and caspase 3/7 activity, though with lower efficacy than in monolayers. Arsenite cytotoxicity was enhanced by lower CatL activity, since similar cytotoxicity increase was also observed using the novel CatL inhibitor AT094. The results have significant translational impact, since stable CatL silencing would enable the application of lower systemic doses of arsenite to achieve the desired cytotoxic effects on GBMs in vivo.

Roberts I, O'Connor D, Roy A, et al.
The impact of trisomy 21 on foetal haematopoiesis.
Blood Cells Mol Dis. 2013; 51(4):277-81 [PubMed] Related Publications
The high frequency of a unique neonatal preleukaemic syndrome, transient abnormal myelopoiesis (TAM), and subsequent acute myeloid leukaemia in early childhood in patients with trisomy 21 (Down syndrome) points to a specific role for trisomy 21 in transforming foetal haematopoietic cells. N-terminal truncating mutations in the key haematopoietic transcription factor GATA1 are acquired during foetal life in virtually every case. These mutations are not leukaemogenic in the absence of trisomy 21. In mouse models, deregulated expression of chromosome 21-encoded genes is implicated in leukaemic transformation, but does not recapitulate the effects of trisomy 21 in a human context. Recent work using primary human foetal liver and bone marrow cells, human embryonic stem cells and iPS cells shows that prior to acquisition of GATA1 mutations, trisomy 21 itself alters human foetal haematopoietic stem cell and progenitor cell biology causing multiple abnormalities in myelopoiesis and B-lymphopoiesis. The molecular basis by which trisomy 21 exerts these effects is likely to be extremely complex, to be tissue-specific and lineage-specific and to be dependent on ontogeny-related characteristics of the foetal microenvironment.

Ajeawung NF, Faure R, Jones C, Kamnasaran D
Preclinical evaluation of dipotassium bisperoxo (picolinato) oxovanadate V for the treatment of pediatric low-grade gliomas.
Future Oncol. 2013; 9(8):1215-29 [PubMed] Related Publications
AIM: The treatment of pediatric low-grade gliomas with current treatment modalities still remains ineffective among a subset of patients; hence, justifying the need to further investigate more effective therapies. Dipotassium bisperoxo (picolinato) oxovanadate V (Bpv[pic]), is a derivative of the trace metal vanadium and a potent inhibitor of protein tyrosine phosphatases, which are important mediators of oncogenic and tumor suppressive activities in cancers. In this study, we undertook a preclinical evaluation of the antineoplastic functions of Bpv(pic) in the treatment of pediatric low-grade gliomas.
MATERIALS & METHODS: We utilized pediatric low-grade glioma cell lines (Res186, Res259 and R286) in a wide variety of cancer assays to determine whether Bpv(pic) can abrogate the neoplastic properties of these cells.
RESULTS: Our preclinical evaluation of the antineoplastic properties of Bpv(pic) in pediatric low-grade gliomas reveals a significant dose-dependent decrease in cell viability as a consequence of decreased proliferation and sustained induction of growth arrest and apoptosis. Bpv(pic) significantly decreases cell migration/invasion and anchorage-independent growth in soft agarose. Within cells, Bpv(pic) functions by attenuating CDC25A activity, and by decreasing the expression of multiple protein tyrosine phosphatases, DNA repair genes, microtubule-associated genes, such as PLK1, AURKA and HDAC6, and conversely augmenting the expression of proapoptotic mediators such as BAK, AIFM and CTSL1.
CONCLUSION: Collectively, our data strongly suggest novel evidence of Bpv(pic) being a potent antineoplastic drug and a suitable alternative for the treatment of pediatric low-grade gliomas.

Grotsky DA, Gonzalez-Suarez I, Novell A, et al.
BRCA1 loss activates cathepsin L-mediated degradation of 53BP1 in breast cancer cells.
J Cell Biol. 2013; 200(2):187-202 [PubMed] Free Access to Full Article Related Publications
Loss of 53BP1 rescues BRCA1 deficiency and is associated with BRCA1-deficient and triple-negative breast cancers (TNBC) and with resistance to genotoxic drugs. The mechanisms responsible for decreased 53BP1 transcript and protein levels in tumors remain unknown. Here, we demonstrate that BRCA1 loss activates cathepsin L (CTSL)-mediated degradation of 53BP1. Activation of this pathway rescued homologous recombination repair and allowed BRCA1-deficient cells to bypass growth arrest. Importantly, depletion or inhibition of CTSL with vitamin D or specific inhibitors stabilized 53BP1 and increased genomic instability in response to radiation and poly(adenosine diphosphate-ribose) polymerase inhibitors, compromising proliferation. Analysis of human breast tumors identified nuclear CTSL as a positive biomarker for TNBC, which correlated inversely with 53BP1. Importantly, nuclear levels of CTSL, vitamin D receptor, and 53BP1 emerged as a novel triple biomarker signature for stratification of patients with BRCA1-mutated tumors and TNBC, with potential predictive value for drug response. We identify here a novel pathway with prospective relevance for diagnosis and customization of breast cancer therapy.

Ono M, Tanaka RJ, Kano M, Sugiman T
Visualising the cross-level relationships between pathological and physiological processes and gene expression: analyses of haematological diseases.
PLoS One. 2013; 8(1):e53544 [PubMed] Free Access to Full Article Related Publications
The understanding of pathological processes is based on the comparison between physiological and pathological conditions, and transcriptomic analysis has been extensively applied to various diseases for this purpose. However, the way in which the transcriptomic data of pathological cells relate to the transcriptomes of normal cellular counterparts has not been fully explored, and may provide new and unbiased insights into the mechanisms of these diseases. To achieve this, it is necessary to develop a method to simultaneously analyse components across different levels, namely genes, normal cells, and diseases. Here we propose a multidimensional method that visualises the cross-level relationships between these components at three different levels based on transcriptomic data of physiological and pathological processes, by adapting Canonical Correspondence Analysis, which was developed in ecology and sociology, to microarray data (CCA on Microarray data, CCAM). Using CCAM, we have analysed transcriptomes of haematological disorders and those of normal haematopoietic cell differentiation. First, by analysing leukaemia data, CCAM successfully visualised known relationships between leukaemia subtypes and cellular differentiation, and their characteristic genes, which confirmed the relevance of CCAM. Next, by analysing transcriptomes of myelodysplastic syndromes (MDS), we have shown that CCAM was effective in both generating and testing hypotheses. CCAM showed that among MDS patients, high-risk patients had transcriptomes that were more similar to those of both haematopoietic stem cells (HSC) and megakaryocyte-erythroid progenitors (MEP) than low-risk patients, and provided a prognostic model. Collectively, CCAM reveals hidden relationships between pathological and physiological processes and gene expression, providing meaningful clinical insights into haematological diseases, and these could not be revealed by other univariate and multivariate methods. Furthermore, CCAM was effective in identifying candidate genes that are correlated with cellular phenotypes of interest. We expect that CCAM will benefit a wide range of medical fields.

Ajeawung NF, Maltais R, Jones C, et al.
Viability screen on pediatric low grade glioma cell lines unveils a novel anti-cancer drug of the steroid biosynthesis inhibitor family.
Cancer Lett. 2013; 330(1):96-105 [PubMed] Related Publications
Pediatric low grade gliomas are the most common central nervous system tumors and are still incurable among a subset of patients despite current treatment modalities. Steroid biosynthesis occurs in a wide variety of organs including the brain, to mediate an assortment of functions, including a proposed role in the growth of gliomas. Hence, targeting steroid biosynthesis and/or their signaling pathways, is anticipated as an effective approach for treating gliomas. In this study, we investigated whether our chemical library of steroid inhibitors can modulate the growth of pediatric low grade glioma cell lines (Res186, Res259, R286), and subsequently identified a potent inhibitor of 17β-hydroxysteroid dehydrogenase type 3, referred to as DK16, which functions by attenuating cell viability, proliferation, migration/invasion and anchorage independent growth and conversely induces apoptosis and cell cycle arrest in a dose and duration dependent manner. Further investigations into the mechanisms of how DK16 functions showed that this drug increased the BAX/BCL2 expression ratio, induced phosphatidylserine externalization, and mitochondrial membrane depolarizations culminating to the release and nuclear translocation of AIF. In addition, treatments of low grade glioma cell lines with DK16 increased the expression of pro-apoptotic mediators including CDK2 and CTSL1, and with the converse diminished expression of pro-survival and migratory/invasion genes like PRKCA, TERT, MAPK8, MMP1 and MMP2. Our findings collectively demonstrate the potent anti-neoplastic properties of DK16, a steroid biosynthesis inhibitor, on the growth of pediatric low grade gliomas.

Yin M, Soikkeli J, Jahkola T, et al.
TGF-β signaling, activated stromal fibroblasts, and cysteine cathepsins B and L drive the invasive growth of human melanoma cells.
Am J Pathol. 2012; 181(6):2202-16 [PubMed] Related Publications
Accumulating evidence indicates that interactions between cancer cells and stromal cells are important for the development/progression of many cancers. Herein, we found that the invasive growth of melanoma cells in three-dimensional-Matrigel/collagen-I matrices is dramatically increased on their co-culture with embryonic or adult skin fibroblasts. Studies with fluorescent-labeled cells revealed that the melanoma cells first activate the fibroblasts, which then take the lead in invasion. To identify the physiologically relevant invasion-related proteases involved, we performed genome-wide microarray analyses of invasive human melanomas and benign nevi; we found up-regulation of cysteine cathepsins B and L, matrix metalloproteinase (MMP)-1 and -9, and urokinase- and tissue-type plasminogen activators. The mRNA levels of cathepsins B/L and plasminogen activators, but not MMPs, correlated with metastasis. The invasiveness/growth of the melanoma cells with fibroblasts was inhibited by cell membrane-permeable inhibitors of cathepsins B/L, but not by wide-spectrum inhibitors of MMPs. The IHC analysis of primary melanomas and benign nevi revealed cathepsin B to be predominantly expressed by melanoma cells and cathepsin L to be predominantly expressed by the tumor-associated fibroblasts surrounding the invading melanoma cells. Finally, cathepsin B regulated TGF-β production/signaling, which was required for the activation of fibroblasts and their promotion of the invasive growth of melanoma cells. These data provide a basis for testing inhibitors of TGF-β signaling and cathepsins B/L in the therapy of invasive/metastatic melanomas.

Zhou L, El-Deiry W, Wang W, et al.
Extracellular protease imaging for cell mass tracking of xenografted human malignant pleural mesothelioma.
Oncol Rep. 2012; 28(3):883-8 [PubMed] Related Publications
Malignant pleural mesothelioma (MPM) is locally aggressive and challenging to quantitate non-invasively in vivo, particularly in orthotopic models of disease. We describe imaging of extracellular protease activity, typically elevated in locally aggressive tumors, as a novel method for tracking MPM in vivo. Mice bearing human MPM subcutaneous flank xenografted tumors were imaged with ProSense 680, an optical imaging agent of extracellular cysteine protease activity. The relative contribution of extracellular cysteine proteases to the ProSense tumor signal was estimated using RT-PCR quantitation of cysteine protease RNA expression of the MPM cell lines and compared to ArrayExpress microarray RNA expression data from human MPM tumors. Feasibility of orthotopic intraperitoneal MPM cell mass tracking with fluorescence signal was evaluated using CellVue Maroon-coated MSTO-211H and compared to bioluminescent signal using luciferase-transfected MSTO-211H cells. ProSense 680 yielded a robust tumor signal in MPM subcutaneous grafts, primarily resulting from MPM secretion of cathepsin L demonstrated not only by RT-PCR data on MPM cell lines but also by microarray expression data from resected human patient tumors. CellVue Maroon intraperitoneal tumor signal was robust and durable indicating feasibility of intraperitoneal cell mass tracking of orthotopically-xenografted MPM. Optical imaging of extracellular cysteine protease activity is useful for tracking MPM tumor cell mass in vivo. Intraperitoneal MPM cell mass tracking of fluorescently labeled tumor is feasible.

Yu JB, Zhang YC, Yang QP, et al.
Invasion-associated genes identified by gene expression profiling in extranodal natural killer/T-cell lymphoma, nasal type.
Leuk Lymphoma. 2013; 54(1):90-8 [PubMed] Related Publications
To identify invasion-associated genes in extranodal natural killer (NK)/T-cell lymphoma, we performed microarray analysis on seven tumor samples and two control pools (composed of normal NK cells and T cells, tonsil and spleen) using Affymetrix GeneChip. Compared with all control pools, 59 uniquely expressed genes were discovered in the tumor samples. Overexpressed genes related to proteolysis, cell motility and chemotaxis, including CTSL, uPAR, TIMP-1, CXCL9, CXCL11 and DEFB1, were identified. Comparing the gene expression profiles of five upper aerodigestive tract (UAT) cases with two non-UAT cases, we found some overexpressed genes in non-UAT cases related to proteolysis and cell adhesion function, including matrix metalloproteinase 9 (MMP-9). Immunohistochemistry detection was performed on 34 paraffin sections to evaluate the expression of selected genes. A correlation of urokinase-type plasminogen activator receptor (uPAR) expression with MMP-9 expression was revealed. Analysis of prognosis demonstrated that expressions of MMP-2 and MMP-9 were closely correlated with a poor prognosis. These invasion-associated genes may become targets for diagnostic and therapeutic procedures.

Luistro LL, Rosinski JA, Bian H, et al.
Development and characterization of a preclinical ovarian carcinoma model to investigate the mechanism of acquired resistance to trastuzumab.
Int J Oncol. 2012; 41(2):639-51 [PubMed] Related Publications
Trastuzumab (Herceptin®) is a humanized monoclonal antibody designed to bind and inhibit the function of the human epidermal growth factor receptor 2 (HER2)/erbB2 receptor. Trastuzumab has demonstrated clinical activity in several types of HER2-overexpressing epithelial tumors, such as breast and metastatic gastric or gastroesophageal junction cancer. Relapse and therapeutic resistance, however, still occur in a subset of patients treated with regimens including trastuzumab, despite significant improvements in response rates, survival and quality of life. To investigate the potential mechanisms of acquired therapeutic resistance to trastuzumab, we developed a preclinical model of human ovarian cancer cells, SKOV-3 Herceptin-resistant (HR), and examined the corresponding changes in gene expression profiles. SKOV-3 HR cells were developed by in vivo serial passaging of parental trastuzumab-sensitive SKOV-3 cells. Following four rounds of serial transplantation of 'break-through' xenograft tumors under trastuzumab treatment, significant and reproducible differences in the effects of trastuzumab treatment between SKOV-3 HR and SKOV-3 cells in vivo and in vitro were revealed. SKOV-3 HR cells retained HER2 protein expression but were unaffected by the antiproliferative effects of trastuzumab. The trastuzumab binding affinity for SKOV-3 HR cells was diminished, despite these cells having more binding sites for trastuzumab. Microarray expression profiling (MEP) was performed to determine the genes involved in the resistance mechanism. Functional analysis revealed the differential expression of genes potentially involved in angiogenesis, metastasis, differentiation and proliferation, such as mucin1 (MUC1). Immunohistochemical staining of SKOV-3 HR cells demonstrated a marked overexpression of MUC1. Based on these data, we hypothesize that the overexpression of MUC1 may hinder trastuzumab binding to HER2 receptors, abrogating the antitumor effects of trastuzumab and thus could contribute to resistance to therapy. Moreover, the resultant MEP preclinical gene signature in this preclinical model system may provide the basis for further investigation of potential clinical mechanisms of resistance to trastuzumab.

Rafn B, Nielsen CF, Andersen SH, et al.
ErbB2-driven breast cancer cell invasion depends on a complex signaling network activating myeloid zinc finger-1-dependent cathepsin B expression.
Mol Cell. 2012; 45(6):764-76 [PubMed] Related Publications
Aberrant ErbB2 receptor tyrosine kinase activation in breast cancer is strongly linked to an invasive disease. The molecular basis of ErbB2-driven invasion is largely unknown. We show that cysteine cathepsins B and L are elevated in ErbB2 positive primary human breast cancer and function as effectors of ErbB2-induced invasion in vitro. We identify Cdc42-binding protein kinase beta, extracellular regulated kinase 2, p21-activated protein kinase 4, and protein kinase C alpha as essential mediators of ErbB2-induced cysteine cathepsin expression and breast cancer cell invasiveness. The identified signaling network activates the transcription of cathepsin B gene (CTSB) via myeloid zinc finger-1 transcription factor that binds to an ErbB2-responsive enhancer element in the first intron of CTSB. This work provides a model system for ErbB2-induced breast cancer cell invasiveness, reveals a signaling network that is crucial for invasion in vitro, and defines a specific role and targets for the identified serine-threonine kinases.

Gole B, Huszthy PC, Popović M, et al.
The regulation of cysteine cathepsins and cystatins in human gliomas.
Int J Cancer. 2012; 131(8):1779-89 [PubMed] Related Publications
Cysteine cathepsins play an important role in shaping the highly infiltrative growth pattern of human gliomas. We have previously demonstrated that the activity of cysteine cathepsins is elevated in invasive glioblastoma (GBM) cells in vitro, in part due to attenuation of their endogenous inhibitors, the cystatins. To investigate this relationship in vivo, we established U87-MG xenografts in non-obese diabetic (NOD)/severe combined immunodeficiency (SCID)-enhanced green fluorescent protein (eGFP) mice. Here, tumor growth correlated with an elevated enzymatic activity of CatB both in the tumor core and at the periphery, whereas CatS and CatL levels were higher at the xenograft edge compared to the core. Reversely, StefB expression was detected in the tumor core, but it was generally absent in the tumor periphery, suggesting that down-regulation of this inhibitor correlates with in vivo invasion. In human GBM samples, all cathepsins were elevated at the tumor periphery compared to brain parenchyma. CatB was also typically associated with angiogenic endothelia and necrotic areas. StefB was mainly detected in the tumor core, whereas CysC and StefA were evenly distributed, reflecting the observations in the xenografts. However, at the mRNA level, no differences in cathepsins and cystatins were observed between the tumor center and the periphery in both human biopsies and xenografts. Interestingly, in human tumors, cathepsin and stefin transcript levels correlated with CD68 and CXCR4 levels, but not with epidermal growth factor receptor (EGFR). Moreover, we reveal for the first time that an elevated StefA mRNA level is a highly significant prognostic factor for patient survival.

Takamori A, Hasegawa A, Utsunomiya A, et al.
Functional impairment of Tax-specific but not cytomegalovirus-specific CD8+ T lymphocytes in a minor population of asymptomatic human T-cell leukemia virus type 1-carriers.
Retrovirology. 2011; 8:100 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in a small percentage of infected individuals. ATL is often associated with general immune suppression and an impaired HTLV-1-specific T-cell response, an important host defense system. We previously found that a small fraction of asymptomatic HTLV-1-carriers (AC) already showed impaired T-cell responses against the major target antigen, Tax. However, it is unclear whether the impaired HTLV-1 Tax-specific T-cell response in these individuals is an HTLV-1-specific phenomenon, or merely reflects general immune suppression. In this study, in order to characterize the impaired HTLV-1-specific T-cell response, we investigated the function of Tax-specific CD8+ T-cells in various clinical status of HTLV-1 infection.
RESULTS: By using tetramers consisting of HLA-A*0201, -A*2402, or -A*1101, and corresponding Tax epitope peptides, we detected Tax-specific CD8+ T-cells in the peripheral blood from 87.0% of ACs (n = 20/23) and 100% of HAM/TSP patients (n = 18/18) tested. We also detected Tax-specific CD8+ T-cells in 38.1% of chronic type ATL (cATL) patients (n = 8/21), although its frequencies in peripheral blood CD8+ T cells were significantly lower than those of ACs or HAM/TSP patients. Tax-specific CD8+ T-cells detected in HAM/TSP patients proliferated well in culture and produced IFN-γ when stimulated with Tax peptides. However, such functions were severely impaired in the Tax-specific CD8+ T-cells detected in cATL patients. In ACs, the responses of Tax-specific CD8+ T-cells were retained in most cases. However, we found one AC sample whose Tax-specific CD8+ T-cells hardly produced IFN-γ, and failed to proliferate and express activation (CD69) and degranulation (CD107a) markers in response to Tax peptide. Importantly, the same AC sample contained cytomegalovirus (CMV) pp65-specific CD8+ T-cells that possessed functions upon CMV pp65 peptide stimulation. We further examined additional samples of two smoldering type ATL patients and found that they also showed dysfunctions of Tax-specific but not CMV-specific CD8+ T-cells.
CONCLUSIONS: These findings indicated that Tax-specific CD8+ T-cells were scarce and dysfunctional not only in ATL patients but also in a limited AC population, and that the dysfunction was selective for HTLV-1-specifc CD8+ T-cells in early stages.

Hashida Y, Nemoto Y, Imajoh M, et al.
Promoter methylation of the bone morphogenetic protein 6 gene in multiple myeloma.
Oncol Rep. 2012; 27(3):825-30 [PubMed] Related Publications
Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor-β superfamily, are multifunctional signaling molecules that have become of increasing interest in cancer research. Recent observations suggest that alterations in BMPs and BMP signaling are associated with tumorigenesis and disease progression in various types of malignancies. This study investigated the methylation status of the BMP6 gene promoter in various types of plasma cell proliferative disorders by combined bisulfite restriction analysis. While BMP6 methylation was not detected in any samples from monoclonal gammopathies of undetermined significance, intramedullary multiple myeloma (MM), plasma cell leukemia or solitary plasmacytoma, both case studies and cell line studies showed that multiple extramedullary plasmacytoma (MEP) consistently carried a methylated BMP6 promoter. The BMP6 methylation-positive MEP was an aggressive form of MM with extremely high levels of serum lactate dehydrogenase (LDH). Bisulfite sequencing analysis confirmed intensive methylation at CpG sites of the BMP6 promoter region. The methylation of BMP6 was correlated with decreased levels of mRNA transcripts. Expression of BMP6 was restored by the demethylating agent 5-aza-2'-deoxycytidine, suggesting that the methylation is associated with transcriptional silencing. Our study implied that BMP6 promoter methylation is not a common event in MMs, but occurs in aggressive MEP. These findings warrant further investigation to clarify whether BMP6 methylation together with elevated LDH could be a marker of poor prognosis in MEP patients who should be considered for early intensive treatment.

Samaiya M, Bakhshi S, Shukla AA, et al.
Epigenetic regulation of cathepsin L expression in chronic myeloid leukaemia.
J Cell Mol Med. 2011; 15(10):2189-99 [PubMed] Free Access to Full Article Related Publications
The expression and significance of cathepsin L (CTSL) has been extensively studied in solid tumours. However no such information in chronic myeloid leukaemia (CML) was available. We investigated the activity and expression of this protease in peripheral blood mononuclear cells (PBMCs) of 47 adult CML patients. Thirty adults suffering from systemic diseases and 50 healthy volunteers served as controls. The mRNA levels of CTSL, its specific endogenous inhibitor cystatin C and transcriptional up-regulator vascular endothelial growth factor (VEGF) were quantitated by real-time qPCR. CTSL protease activity and its mRNA expression were significantly higher in CML chronic phase (CP) patients compared to CML accelerated phase/blast crisis (AP/BC) patients and controls (P≤ 0.001). VEGF whose expression was most pronounced in CP and declined (P≤ 0.001) in the advanced phases of the malignancy exhibited a strong positive correlation with CTSL expression (r= 0.97; P≤ 0.001). Cystatin C expression was significantly lower (P≤ 0.001) in CML and displayed inverse correlation with CTSL (r=-0.713; P≤ 0.001) activity. CTSL promoter was significantly hypomethylated in CML CP compared to CML AP/BC patients as well as controls. K562, a BC CML cell line displayed CTSL activity, expression and methylation status of CTSL promoter that was comparable to CML AP/BC patients. Treatment of these cells or PBMCs isolated from CML AP/BC patients with 5'-aza-cytidine resulted in a dramatic increase in CSTL activity and/or expression thereby demonstrating the role of promoter methylation in the stage specific expression of CTSL in CML. Differential expression of CTSL in CML at various stages of malignancy may prove useful in identification of the high-risk patients thereby facilitating better management of disease.

Ganjoo KN, Witten D, Patel M, et al.
The prognostic value of tumor-associated macrophages in leiomyosarcoma: a single institution study.
Am J Clin Oncol. 2011; 34(1):82-6 [PubMed] Related Publications
INTRODUCTION: High numbers of tumor-associated macrophages (TAMs) have been associated with poor outcome in several solid tumors. In 2 previous studies, we showed that colony stimulating factor-1 (CSF1) is secreted by leiomyosarcoma (LMS) and that the increase in macrophages and CSF1 associated proteins are markers for poor prognosis in both gynecologic and nongynecologic LMS in a multicentered study. The purpose of this study is to evaluate the outcome of patients with LMS from a single institution according to the number of TAMs evaluated through 3 CSF1 associated proteins.
METHODS: Patients with LMS treated at Stanford University with adequate archived tissue and clinical data were eligible for this retrospective study. Data from chart reviews included tumor site, size, grade, stage, treatment, and disease status at the time of last follow-up. The 3 CSF1 associated proteins (CD163, CD16, and cathepsin L) were evaluated by immunohistochemistry on tissue microarrays. Kaplan-Meier survival curves and univariate Cox proportional hazards models were fit to assess the association of clinical predictors as well as CSF1 associated proteins with overall survival.
RESULTS: A total of 52 patients diagnosed from 1983 to 2007 were evaluated. Univariate Cox proportional hazards models were fit to assess the significance of grade, size, stage, and the 3 CSF1 associated proteins in predicting OS. Grade, size, and stage were not significantly associated with survival in the full patient cohort, but grade and stage were significant predictors of survival in the gynecologic (GYN) LMS samples (P = 0.038 and P = 0.0164, respectively). Increased cathepsin L was associated with a worse outcome in GYN LMS (P = 0.049). Similar findings were seen with CD16 (P < 0.0001). In addition, CSF1 response enriched (all 3 stains positive) GYN LMS had a poor overall survival when compared with CSF1 response poor tumors (P = 0.001). These results were not seen in non-GYN LMS.
CONCLUSIONS: Our data form an independent confirmation of the prognostic significance of TAMs and the CSF1 associated proteins in LMS. More aggressive or targeted therapies could be considered in the subset of LMS patients that highly express these markers.

Lace MJ, Anson JR, Klussmann JP, et al.
Human papillomavirus type 16 (HPV-16) genomes integrated in head and neck cancers and in HPV-16-immortalized human keratinocyte clones express chimeric virus-cell mRNAs similar to those found in cervical cancers.
J Virol. 2011; 85(4):1645-54 [PubMed] Free Access to Full Article Related Publications
Many human papillomavirus (HPV)-positive high-grade lesions and cancers of the uterine cervix harbor integrated HPV genomes expressing the E6 and E7 oncogenes from chimeric virus-cell mRNAs, but less is known about HPV integration in head and neck cancer (HNC). Here we compared viral DNA status and E6-E7 mRNA sequences in HPV-16-positive HNC tumors to those in independent human keratinocyte cell clones derived from primary tonsillar or foreskin epithelia immortalized with HPV-16 genomes. Three of nine HNC tumors and epithelial clones containing unintegrated HPV-16 genomes expressed mRNAs spliced from HPV-16 SD880 to SA3358 and terminating at the viral early gene p(A) signal. In contrast, most integrated HPV genomes in six HNCs and a set of 31 keratinocyte clones expressed HPV-16 major early promoter (MEP)-initiated mRNAs spliced from viral SD880 directly to diverse cellular sequences, with a minority spliced to SA3358 followed by a cellular DNA junction. Sequence analysis of chimeric virus-cell mRNAs from HNC tumors and keratinocyte clones identified viral integration sites in a variety of chromosomes, with some located in or near growth control genes, including the c-myc protooncogene and the gene encoding FAP-1 phosphatase. Taken together, these findings support the hypothesis that HPV integration in cancers is a stochastic process resulting in clonal selection of aggressively expanding cells with altered gene expression of integrated HPV genomes and potential perturbations of cellular genes at or near viral integration sites. Furthermore, our results demonstrate that this selection also takes place and can be studied in primary human keratinocytes in culture.

Minami Y, Kajiguchi T, Abe A, et al.
Expanded distribution of the T315I mutation among hematopoietic stem cells and progenitors in a chronic myeloid leukemia patient during imatinib treatment.
Int J Hematol. 2010; 92(4):664-6 [PubMed] Related Publications
T315I mutation of the ABL-kinase domain in chronic myeloid leukemia (CML) confers resistance to imatinib (IM) as well as second-generation tyrosine kinase inhibitors (TKIs). We report a chronic-phase CML patient undergoing IM treatment, who showed the overt existence of the T315I mutation after 15 months. We retrospectively analyzed the distribution of the T315I mutation using the invader assay and direct DNA sequencing among FACSAria-sorted populations from bone marrow cells: total mononuclear cells (TMC), hematopoietic stem cells (HSC)/Thy-1(+), HSC/Thy-1⁻, common myeloid progenitors (CMP), granulocyte macrophage progenitors (GMP), and megakaryocyte erythroid progenitors (MEP), at 0, 3, 6, 9, and 12 months after IM treatment. T315I was barely detectable by 12 months in TMC, but detectable in 19.2% of HSC/Thy-1⁻ and 46.4% of MEP at diagnosis, and finally expanded into all populations. These results suggest that the monitoring of gene mutations in HSC and progenitors at diagnosis might be helpful for the early detection of TKI-resistant CML patients and facilitate appropriate therapeutic decision.

Jain M, Bakhshi S, Shukla AA, Chauhan SS
Cathepsins B and L in peripheral blood mononuclear cells of pediatric acute myeloid leukemia: potential poor prognostic markers.
Ann Hematol. 2010; 89(12):1223-32 [PubMed] Related Publications
The diagnostic and prognostic significance of cathepsin B (CTSB) and L (CTSL) is well documented for solid tumors. However, their significance in acute leukemias is lacking. This study was planned to investigate expression and significance of these proteases in peripheral blood mononuclear cells (PBMCs) of patients with pediatric acute myeloid leukemia (AML). CTSL and CTSB activities were assayed in PBMCs of 24 children with AML and ten healthy controls by spectrofluorimetry. The mRNA levels of these proteases and their specific endogenous inhibitor cystatin C and transcriptional upregulator vascular endothelial growth factor (VEGF) were quantitated by real-time PCR. Correlation analysis of CTSL and CTSB activities/expression with their inhibitor/upregulator and event-free survival (EFS) was done using appropriate statistical tools. CTSL and CTSB protease activity and their mRNA expression were significantly higher in AML patients compared to controls (p ≤ 0.001). A strong positive correlation was observed between VEGF expression and CTSL (r = 0.812; p ≤ 0.001). Similarly, VEGF exhibited a strong positive correlation with CTSB (r = 0.501; p = 0.013). Cystatin expression though significantly high (p ≤ 0.001) in AML was negatively correlated with CTSL (r = -0.920; p ≤ 0.001) and CTSB (r = -0.580, p ≤ 0.001) expression. AML patients with higher CTSL and CTSB activity exhibited an inferior EFS (CTSL: p = 0.045; CTSB: p = 0.002) and overall survival (OS; CTSL: p = 0.05; CTSB: p = 0.004) compared to patients with lower levels of these proteases. This is the first report demonstrating increased expression of CTSL and CTSB in AML, mechanism of their increased expression in relation to VEGF, and their association with poor EFS and OS. These results suggest a potential utility of these proteases as prognostic markers for this malignancy.

Katara R, Mir RA, Shukla AA, et al.
Wild type p53-dependent transcriptional upregulation of cathepsin L expression is mediated by C/EBPα in human glioblastoma cells.
Biol Chem. 2010; 391(9):1031-40 [PubMed] Related Publications
Mutations in the tumor suppressor gene p53 are frequent in human glioblastomas. Similarly cathepsin L, a lysosomal cysteine protease, is overexpressed and secreted by most human tumors including glioblastomas. However, hitherto there is no information on whether or not the mutation(s) in the p53 gene affect(s) expression of this protease. Using human glioblastoma cell lines harboring wild type and mutant p53, we demonstrate here for the first time that only the wild type but not the mutant p53 upregulates cathepsin L expression. By transfection of promoter reporter constructs, site-directed mutagenesis and chip assays we have established that wild type p53 elevates the levels of cathepsin L in these cells. It does so directly by binding to the cathepsin L promoter and also indirectly by inducing the expression of C/EBPα, which is crucial for the transcription of this protease. In view of its role in tumorigenesis, angiogenesis and tumor cell invasion, increased expression of cathepsin L in glioblastoma cells harboring wild type p53 might confer invasive ability and growth advantage to these cells. Therefore, use of cathepsin L inhibitors could prove useful in the management of these tumors.

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