Abstract C108: Therapeutic potential of anticancer polyherbal formulations

Background: Cancer is a leading cause of death worldwide and poses a huge health challenge (1). The global burden of cancer continues to increase despite advances in cancer therapeutics. There is renewed interest in plant-based drugs and growing appreciation of the use of polyherbal formulations (2). Multitargeted polyherbal formulations provide synergistic or additive preventive effects when the agents are combined could theoretically permit the administration of the lowest active dose of each agent and therefore lower the potential for adverse side effects. Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies and generally considered resistant to chemo- and radiotherapies. Resisting cell death and angiogenesis are two important hallmarks of cancer cells. Therefore, apoptosis and blocking of angiogenesis are crucial therapeutic approaches. The present study aims to evaluate the anticancer potential of four polyherbal formulations on human hepatocellular carcinoma (Hep-G2) cells and their antiangiogenic potential on chick-chorioallantoic membrane.

Materials and Methods: The following were the studies carried out: (i) cytotoxicity using MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay; (ii) apoptosis detection using Annexin V-FITC Propidium Iodide staining and flow cytometry [the frequency of annexin-positive cells (apoptotic) was determined using BD FACSDiva software]; (iii) DNA fragmentation and chromatin condensation evaluated with Hoechst 33258 staining and flourescent microscopy; and (iv) evaluation of atiangiogenic potential the formulations using ex-ovo chick Chorio-Allantoic Membrane (CAM) assay.

Results: All four formulations (VK, MK, KG, and GTK) showed significant cytotoxicity with inhibitory concentration (IC50) of 48.6, 57.0, 41.7, and 48.3 µg/ml, respectively at 24h and 32.4, 31.2, 37.5, 29.9 µg/ml, respectively at 48h of treatment. Maximum apoptosis was observed at concentration of 100 µg/ml in HepG2 cells after 48 h of treatment. Treatment induced apoptosis (cumulative) was 98.8% (VK), 94% (MK), 91.7% (KG), and 97.9% (GTK) at 100 µg/ml, in comparison to 88.6% for paclitaxel (10 µg/ml). Apoptosis was further confirmed by the observation of DNA fragmentation and chromatin condensation in fluorescent microscopy. The formulation VK showed maximum anti-neoplastic activity followed by GTK, MK, and KG. It is interesting to note that the cell death pattern observed with the polyherbal formulations is comparable to that of the synthetic single molecule drug paclitaxel. The microscopic evaluation and morphometric image analysis of area of vascularization revealed that all four formulations showed significant inhibition of neo-vascularization. Maximum anti-angiogenic activity was observed at 100 µg/ml. Inhibition of vascularization observed at 100 µg/ml was 36.6 ± 3.5 mm2 (VK), 30.9 ± 7.0 mm2 (MK), 32.6 ± 6.6 mm2 (KG), and 33.2 ± 4.3 mm2 (GTK). On the other hand, thalidomide resulted in 36.4 ± 3.6 mm2 at 10 µg/ml.

Conclusions: All four classic polyherbal formulations showed significant anticancer and antiangiogenic activity compared to chemothereputic drugs. However, VK and MK showed the maximum anticancer and antiangiogenic activity, respectively.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C108.

Citation Format: Gaurav Sharma, Rama Jayasundar, Shyam S. Chauhan, Thirumurthy Velpandian. Therapeutic potential of anticancer polyherbal formulations. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C108.

Abstract A03: Epigenetic alterations of stratifin in ocular surface squamous neoplasia: Pathogenesis and prognosis

Purpose: Ocular Surface Squamous neoplasia (OSSN) is the most common tumor of conjunctival epithelium associated with risk of permanent visual impairment. It includes conjunctival intraepithelial neoplasia (CIN) and squamous cell carcinoma (SCC).Of the multifactorial etiopathogenesis of OSSN, ultraviolet irradiation has been reported as a major risk factor in the pathogenesis of OSSN. Sunlight induced p53 mutations are known to contribute towards increased risk of OSSN. Stratifin (14-3-3σ)/HEM (human epithelial marker) is a p53 mediated inhibitor of cell cycle progression and has been shown to be a target of epigenetic deregulation in various carcinomas.

In the present study, Stratifin expression, its promoter methylation status and expression of mutant p53 in OSSN was studied. The significance of Stratifin and p53 in the pathogenesis and prognosis of ocular surface squamous neoplasia (OSSN) patients was also evaluated.

Methods: Sixty-four histopathologically confirmed OSSN cases (44 SCC and 20 CIN) were included in this study. AJCC TNM staging was performed and patients were followed up for 32 months. Immunohistochemical expression of Stratifin (clone-ab14123) and mutant p53 (clone-DO7) protein was evaluated; methylation status of Stratifin was determined by methylation specific PCR using specific primers. Kaplan–Meier survival and Cox regression analysis was done to assess the prognostic significance of Stratifin and p53.

Results: Loss of Stratifin immunoexpression was observed in 75% (48/64) and 48% (31/64) cases showed mutant p53 expression. Hypermethylation of Stratifin promoter was seen in 63% (40/64) OSSN cases. Of the 48 cases with loss of Stratifin expression, promoter hypermethylation was seen in 35% (17/48), mutant p53 expression in 10% (5/48) and both promoter hypermethylation and mutant p53 expression in 58% (23/48) cases. These results indicate that both hypermethylation of Stratifin and mutant p53 expression are associated with loss of Stratifin in OSSN cases.

On statistical analysis, Stratifin loss was significantly associated with tumor size >2cm, T3 and T4 category, poor histopathological differentiation of SCC and reduced disease free survival (P 0.05). Cox analysis showed Stratifin to be an independent prognostic marker for OSSN (p =0.03) patients.

Mutant p53 expression was associated with history of longer sunlight exposure in 56% cases. No significant correlation was observed between mutant p53 expression and other clinicopathological feature or clinical outcome.

Conclusions: Our results indicate that loss of Stratifin is a key event in the pathogenesis of OSSN. Presence of both aberrant methylation of Stratifin and mutant p53 expression implicates involvement of p53-Stratifin mediated signalling pathway in the pathogenesis of OSSN. Stratifin loss may also prove to be a useful biomarker for identifying high risk OSSN patients.

Citation Format: Sheetal Chauhan, Seema Sen, Anjana Sharma, Shyam S. Chauhan, Seema Kashyap, Radhika Tandon, Neelam Pushker, M Vanathi. Epigenetic alterations of stratifin in ocular surface squamous neoplasia: Pathogenesis and prognosis. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr A03.

Prognostic significance of extracellular matrix degrading enzymes-cathepsin L and matrix metalloproteases-2 [MMP-2] in human pancreatic cancer

In the present study, we assessed the expression of extracellular matrix (ECM) degrading proteases-cathepsin L and matrix metalloprotease-2 (MMP-2) in pancreatic cancer tissue and correlated their levels with clinicopathological parameters and survival. Both the proteases were expressed in the majority of the tumor tissues examined. Staining intensity of cathepsin L was significantly higher in the tumor stroma compared to tumor epithelium while MMP-2 staining showed no such difference. Both proteases showed correlation with some of the clinicopathological parameters but only cathepsin L expression in tumor epithelium predicted a poor prognosis for the disease.

p38β MAP kinase as a therapeutic target for pancreatic cancer

Pancreatic cancer is very difficult to diagnose in its early stage. Molecular marker and imaging have not proven to be accurate modalities for screening of pancreatic cancer. This study aims to develop p38β as a protein marker for pancreatic cancer and to design peptide inhibitor against the same. The serum p38β level of pancreatic cancer (n = 35; 5.06 μg/mL) was twofold higher compared to that of the chronic pancreatitis (n = 10; 2.92 μg/mL) and matched normal control (n = 10; 2.86 μg/ml) (p < 0.0005). Peptide inhibitors were designed to inhibit the activity of p38β and the kinetic assay had shown the dissociation constant, (K(D)) to be 3.16 × 10(-8) M and IC(50), 25 nM by Surface Plasmon Resonance (SPR) and Enzyme-Linked Immunosorbent Assay (ELISA), respectively. The peptide inhibitor also significantly reduced viability and induced cytotoxicity in Human Pancreatic carcinoma epithelial-like cell line (PANC-1) cells.

Epigenetic regulation of cathepsin L expression in chronic myeloid leukaemia

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.

Abstract B25: Emerging role of heterogeneous ribonucleoproteins (hnRNPs) as early predictive marker and prognosticator for head and neck oral squamous cell carcinoma

Introduction: Recently using iTRAQ-tagging and multidimensional liquid chromatography tandem mass spectrometry (LC-MS/MS), we identified a panel of proteins differentially expressed in head and neck/oral squamous cell carcinoma (HNOSCC) as compared to the non-malignant tissues. Heterogeneous ribonucleoprotein K (hnRNPK) and Heterogeneous ribonucleoprotein D (hnRNPD) are among few of the proteins identified in this panel. These are nuclear protein belonging to the RNA binding protein family. Here, we report the verification of these proteins in an independent set of clinical samples by immunohistochemistry, and investigate their potential as a prognostic biomarker for HNOSCC. The present study also explores their clinical relevance and potential as a biomarker in identification of oral lesions in early stages of malignancy.

Experimental Design: Two hundered HNOSCCs, 100 leukoplakias and 100 non-malignant archived tissues were retrieved from the research tissue bank to determine the expression of hnRNPK using immunohistochemistry (IHC). The IHC data were subjected to statistical analyses using the SPSS 15.0 software (Chicago). Receiver operating characteristic (ROC) analysis was used to determine the sensitivity and specificity as a biomarker. The expression in oral lesions was further validated by immunoblotting and RT-PCR analyses in the same tissue and serum samples as used for IHC.

Results: hnRNPK and hnRNPD expression was found to be significantly increased from normal mucosa to leukoplakia with or without dysplasia to HNOSCC (ptrend&lt;0.001). Abberant cytoplasmic expression of hnRNPK was also observed in HNOSCCs. ROC curve showed high potential of these proteins as a biomarker for HNOSCC. Cytoplasmic hnRNPK overexpression was significantly associated with dedifferentiation of tumors whereas nuclear hnRNP D was significantly associated with tumor size.

In univariate analysis, nuclear as well as cytoplasmic localization of hnRNPK and nuclear hnRNPD were found to be associated with poor survival. There was no correlation between hnRNPK and hnRNPD expression, however, significant reduced disease free survival was obtained for the patients harboring hnRNP D+hnRNP K (p = 0.005; median survival = 11 months) as compared with median disease-free survival of 55 months in the patients showing varied hnRNP D+hnRNP K expression. Cox regression model confirmed that this combination can be a better prognosticator for HNOSCC patients as revealed by multivariate analysis (p=0.013; HR = 2.2, 95% CI = 1.2–4.1). RTPCR and western blotting confirmed our IHC results. hnRNPK was also detected in serum samples of HNOSCC patients.

Conclusion: This is the first large scale study that suggests overexpression of hnRNPK and hnRNPD as an early event in development of HNOSCC. Furthermore, their subcellular localization suggests that they may be associated with increased risk of transformation of oral premalignant lesions and recurrence in HNOSCC. As detected in biological fluid, the potential of hnRNPK as a biomarker should be verified on a large scale. The enhanced performance of the combination of hnRNP D and hnRNP K versus either protein individually, in prognosticating the clinical outcome of HNOSCCs needs to be further explored for its implementation in patient care.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B25.

Prognostic significance of nuclear pSTAT3 in oral cancer

BACKGROUND

Aberrant nuclear accumulation of proteins influences tumor development and may predict biologic aggressiveness and disease prognosis. This study determined the prognostic significance of pSTAT3 (phosphorylayed signal transducer and activator of transcription 3) in oral squamous cell carcinomas (OSCCs).

METHODS AND RESULTS

Using immunohistochemistry, a significant increase in nuclear accumulation of pSTAT3 was observed in 49 of 90 leukoplakias (54.4%) and 63/94 OSCCs (67%) (p(trend) < .001). Increased pSTAT3 was associated with tumor stage (p = .01), nodal metastasis (p = .0018), and tobacco consumption (p = .004). Kaplan-Meier analysis demonstrated that OSCC with increased nuclear pSTAT3 showed significantly reduced disease-free survival (13 months), compared with the patients with no nuclear pSTAT3 expression (64 months, p = .019). Cox regression analysis revealed nuclear pSTAT3 as the most significant predictor of poor prognosis (p = .024, hazard ratio [HR] = 2.7).

CONCLUSIONS

Increased nuclear accumulation of pSTAT3 occurs in early premalignant stages and is a marker for poor prognosis of OSCC.

Wild type p53-dependent transcriptional upregulation of cathepsin L expression is mediated by C/EBP&#x03B1; in human glioblastoma cells

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.

Study of methyl transferase (G9aMT) and methylated histone (H3-K9) expressions in unexplained recurrent spontaneous abortion (URSA) and normal early pregnancy

We investigated the expression of methyl transferase G9a and methylated histone H3-K9 in fresh human decidual/endometrial tissue of 12 normal early pregnancies and 15 unexplained recurrent spontaneous abortions (URSA). The samples were obtained through dilatation and curettage and collected as per strict inclusion-exclusion criteria. The tissue was subjected to immunohistochemical analysis (IHC), western blotting (WB) and RT-PCR analysis. The results demonstrated methyl transferase G9a to have a lower expression in abortions when compared with that in normal pregnancy (P < 0.05). The sensitivity of RT-PCR, IHC and WB were respectively 66.67, 75 and 71.43%, while specificity of the same were 66.67, 60 and 78.92%, respectively. Methylated histone H3-K9 was significantly lower (P < 0.0001) in URSA tissues than in controls. This study suggests that methylation may cause URSA and indicates the need for further work to explore the role of methylation in URSA and its possible prevention through locally acting methylating/demethylating agents.

Post-transcriptional regulation of human cathepsin L expression

The expression of cathepsin L, a lysosomal protease, is known to be elevated in cancer and other pathologies. Multiple splice variants of human cathepsin L with variable 5'UTRs exist, which encode for the same protein. Previously we have observed that variant hCATL A (bearing the longest 5'UTR) was translated in vitro with significantly lower efficiency than variant hCATL AIII (bearing the shortest 5'UTR). Contrary to these findings, results of the present study reveal that in cancer cells, hCATL A mRNA exhibits higher translatability in spite of having lower stability than AIII. This is the first report demonstrating a highly contrasting trend in translation efficiencies of hCATL variants in rabbit reticulocytes and live cells. Expression from chimeric mRNAs containing 5'UTRs of A or AIII upstream to luciferase reporter cDNA established the A UTR to be the sole determinant for this effect. Transient transfections of bicistronic plasmids and mRNAs confirmed the presence of a functional Internal Ribosome Entry Site in this UTR. Our data suggest that differential stability and translation initiation modes mediated by the 5'UTRs of human cathepsin L variants are involved in regulating its expression.

Ets-1/Elk-1 is a critical mediator of dipeptidyl-peptidase III transcription in human glioblastoma cells

Dipetidyl-peptidase III is a metallopeptidase involved in a number of physiological processes and its expression has been reported to increase with the histological aggressiveness of human ovarian primary carcinomas. Because no information regarding the regulation of its expression was available, experiments were designed to clone, define and characterize the promoter region of the human dipeptidyl-peptidase III (DPP-III) gene. In this study, we cloned a 1038 bp 5'-flanking DNA fragment of the human DPP-III gene for the first time and demonstrated strong promoter activity in this region. Deletion analysis revealed that as few as 45 nucleotides proximal to the transcription start site retained approximately 40% of the activity of the full-length promoter. This promoter lacked the TATA box but contained multiple GC boxes and a single CAAT box. Similarly, two Ets-1/Elk-1-binding motifs are present in the first 25 nucleotides from the transcription start site. Binding of Ets-1/Elk-1 proteins to these motifs was visualized by electrophoretic mobility shift and chromatin immunoprecipitation assays. Mutations of these binding sites abolished not only binding of the Ets protein, but also the intrinsic promoter activity. Increased DNA-binding activity of Ets-1/Elk-1 by v-Ha-ras also augmented the mRNA level and promoter activity of this gene. Similarly, co-transfection of DPP-III promoter-reporter constructs with Ets-1 expression vector led to a significant increase in promoter activity. From these results, we conclude that Ets-1/Elk-1 plays a critical role in transcription of the human DPP-III gene.

iTRAQ-multidimensional liquid chromatography and tandem mass spectrometry-based identification of potential biomarkers of oral epithelial dysplasia and novel networks between inflammation and premalignancy

Chronic exposure of the oral mucosa to carcinogens in tobacco is linked to inflammation and development of oral premalignant lesions (OPLs) with high risk of progression to cancer; there is currently no clinical methodology to identify high-risk lesions. We hypothesized that identification of differentially expressed proteins in OPLs in relation to normal oral tissues using proteomic approach will reveal changes in multiple cellular pathways and aid in biomarker discovery. Isobaric mass tags (iTRAQ)-labeled oral dysplasias and normal tissues were compared against pooled normal control by online liquid chromatography and tandem mass spectrometry. Verification of biomarkers was carried out in an independent set of samples by immunohistochemistry, immunoblotting, and RT-PCR. We identified 459 nonredundant proteins in OPLs, including structural proteins, signaling components, enzymes, receptors, transcription factors, and chaperones. A panel of three best-performing biomarkers identified by iTRAQ analysis and verified by immunohistochemistrystratifin (SFN), YWHAZ, and hnRNPKachieved a sensitivity of 0.83, 0.91, specificity of 0.74, 0.95, and predictive value of 0.87 and 0.96, respectively, in discriminating dysplasias from normal tissues, thereby confirming their utility as potential OPL biomarkers. Pathway analysis revealed direct interactions between all the three biomarkers and their involvement in two major networks involved in inflammation, signaling, proliferation, regulation of gene expression, and cancer. In conclusion, our work on determining the OPL proteome unraveled novel networks linking inflammation and development of epithelial dysplasia and their key regulatory proteins may serve as novel chemopreventive/therapeutic targets for early intervention. Additionally, we identified and verified a panel of OPL biomarkers that hold promise for large-scale validation for ultimate clinical use.

Immunological responses to a 39.8kDa Plasmodium vivax tryptophan-rich antigen (PvTRAg39.8) among humans

Tryptophan-rich protein from P. yoelii called PypAg3 had shown protection in a murine model. We describe here its P. vivax orthologue named PvTRAg39.8 which is expressed during schizont stages of the parasite. The transcription initiation site was mapped to the -41 nucleotide position from the first AUG codon and thus established the ORF of PvTRAg39.8 which codes for a 322aa long protein. The sequence of this protein is highly conserved among the P. vivax isolates. Recombinant PvTRAg39.8 was expressed in E. coli, purified to electrophoretic homogeneity, and used for immunological studies. A majority of P. vivax-exposed individuals (90%, n=50) contained antibodies against the recombinant PvTRAg39.8. There was a switching of immunoglobulin isotypes against this antigen from IgG1 to IgG4 among individuals from the acute phase of P. vivax infection to convalescence. The PBMCs of 80% of the total 20 P. vivax-exposed individuals showed proliferation when stimulated with this antigen. The cytokine pattern produced by the PBMCs of the P. vivax-exposed individuals, after stimulation with this antigen, indicated a mixed type of immune response with a distinct bias towards the Th2 anti-inflammatory profile. Because of its high natural immunogenicity, conserved nature, and the protective properties of its P. yoelii counterpart, this protein may be a potential candidate for developing the immunotherapeutic reagents.

Studies on production performance and toxin residues in tissues and eggs of layer chickens fed on diets with various concentrations of aflatoxin AFB1

1. An experiment on 1-week-old, White Leghorn female chicks was conducted to study the effect of aflatoxin AFB1 on weight gain, feed intake, feed gain ratio, age at sexual maturity, production and quality of eggs, retention of nutrients, pathoanatomical and histopathological parameters, and also on AFB1 residues in eggs and muscles of hens. The chicks were assigned to 4 dietary treatments: D1 (without AFB1), D2 (2.50 mg/kg AFB1), D3 (3.13 mg/kg AFB1), D4 (3.91 mg/kg AFB1) up to the age of 40 weeks. 2. At the end of the experiment, the mean body weight gain and feed intake were significantly lower in all aflatoxin-fed groups compared to control. The feed gain ratios were noted as 13.41, 13.59, 13.82 and 14.71, with the group fed the highest concentration of AFB1 showing a significantly poorer ratio than other groups. 3. Age at sexual maturity was also affected adversely by dietary AFB1: 193 d for D4 as compared to as early as 148 d for D1. Hen-d egg production was recorded as 96.92, 74.67, 65.98 and 50.75 in D1, D2, D3 and D4, respectively. 4. Average egg weights at the end of the experiment were 57.77, 57.49, 57.54 and 54.66 for D1, D2, D3 and D4, respectively. Shape index was significantly lower in D4 as compared to control. Contrary to this, albumen index was significantly higher in D4 as compared to D1. The values of yolk indices and eggshell thickness did not differ significantly among treatment groups. However, colour of yolk was reduced in all aflatoxin-fed groups compared to control. 5. Retentions of dry matter, crude protein, ether extract, calcium and metabolisable energy were adversely affected at various levels of AFB1 compared to control. 6. Pathoanatomical and histopathological studies showed various adverse changes in liver, kidney, heart, ovaries and bursa of Fabricius in AFB1-fed groups. 7. Different amounts of aflatoxin residues were detected in eggs and breast muscles of hen in all AFB1-fed groups.

Increased expression and activity of nuclear cathepsin L in cancer cells suggests a novel mechanism of cell transformation

It is generally accepted that the role of cathepsin L in cancer involves its activities outside the cells once it has been secreted. However, cathepsin L isoforms that are devoid of a signal peptide were recently shown to be present in the nucleus where they proteolytically process the CCAAT-displacement protein/cut homeobox (CDP/Cux) transcription factor. A role for nuclear cathepsin L in cell proliferation could be inferred from the observation that the CDP/Cux processed isoform can accelerate entry into S phase. Here, we report that in many transformed cells the proteolytic processing of CDP/Cux is augmented and correlates with increased cysteine protease expression and activity in the nucleus. Taking advantage of an antibody that recognizes the prodomain of human cathepsin L, we showed that human cells express short cathepsin L species that do not contain a signal peptide, do not transit through the endoplasmic reticulum, are not glycosylated, and localize to the nucleus. We also showed that transformation by the ras oncogene causes rapid increases both in the production of short nuclear cathepsin L isoforms and in the processing of CDP/Cux. Using a cell-based assay, we showed that a cell-permeable inhibitor of cysteine proteases is able to delay the progression into S phase and the proliferation in soft agar of ras-transformed cells, whereas the non-cell-permeable inhibitor had no effect. Taken together, these results suggest that the role of cathepsin L in cancer might not be limited to its extracellular activities but may also involve its processing function in the nucleus.

Transcriptional upregulation of human cathepsin L by VEGF in glioblastoma cells

The role of vascular endothelial growth factor (VEGF) on cathepsin L expression was investigated in human glioblastoma cells (U87MG). Our results demonstrate the transcriptional upregulation of cathepsin L expression by VEGF. Transient transfection of U87MG cells with VEGF expression vector significantly increased cathepsin L activity. These results were further corroborated by a parallel increase in the mRNA levels and promoter activity of cathepsin L by VEGF. By deletion analysis, we identified a 47 base pair VEGF response element (VRE) in human cathepsin L promoter. Site directed mutagenesis studies demonstrated that both SP-1 and AP-4 motifs present in this region contribute to VEGF responsiveness. These results prove for the first time that over-expression of VEGF in human glioblastoma cells induces cathepsin L expression at the transcriptional level. This mechanism could be involved in the enhanced tumorogenic potential of these cells.

Distribution of CCR5Δ32, CCR2-64I and SDF1-3′A and plasma levels of SDF-1 in HIV-1 seronegative North Indians

Host genetic factors play an important role in susceptibility to HIV-1 infection and progression to AIDS. Mutations in genes encoding chemokine receptors and their ligands, viz., CCR5delta32, CCR2-64I and SDF1-3'A are implicated to have protective effects against HIV-1 infection and/or disease progression. The distribution of these gene polymorphisms and their role in the course of the disease varies between individuals of different racial, ethnic and risk groups. We have examined the allelic frequencies of CCR5delta32, CCR2-64I and SDF1-3'A in 500 healthy North Indians tested seronegative for HIV-1, by PCR-RFLP. The plasma levels of stromal derived factor (SDF-1) protein were estimated in 75 individuals using ELISA kit. Frequencies of CCR5delta32, CCR2-64I and SDF1-3'A alleles in 500 individuals were 1.5%, 9.1% and 20.4%, respectively. The SDF1-3'A homozygosity was confirmed by PCR product cloning and sequencing. The relative hazard values calculated on the basis of the three locus genotype of each individual revealed high relative hazard values (>0.9). The plasma levels of SDF-1 ranged from 1.77 to 3.42 ng/ml and were comparable between the three genotypes of SDF-1. This is the first study to assess the plasma level of SDF-1 protein in Asian Indians. Low frequency of the protective allele CCR5delta32 observed in this study suggests high vulnerability of North Indians to HIV-1 infection. The precise role of SDF1-3'A in HIV-1 infection needs to be elucidated.

Identification and functional characterization of a novel unspliced transcript variant of HIC-1 in human cancer cells exposed to adverse growth conditions

The wild-type p53 gene has been widely implicated in the regulation of hypermethylated in cancer-1 (HIC-1) transcription, a master growth regulatory gene with multiple promoters and, consequently, multiple alternatively spliced transcripts. We investigated the role of p53 (wild type and mutant, both endogenous and exogenous) in modulating the various HIC-1 transcripts. We discovered a novel unspliced HIC-1 transcript, identified as "f" in leukocytes and in the human cell lines U87MG (wild-type p53), U373MG (mutant p53), MCF-7 (wild-type p53), HeLa (p53 degraded by HPV18-E6 oncoprotein), and Saos-2 (p53 null). This transcript is initiated from a new transcription start site and has an intervening stop codon that would result in a possibly truncated 22-amino-acid polypeptide. When U87MG (wild-type p53) and MCF-7 cells (wild-type p53) were exposed to adverse growth conditions of serum starvation or treated with the chemotherapeutic agent cisplatin, cells underwent apoptosis and cell cycle arrest accompanied by increase in p53 and HIC-1 transcript levels. Although the increase of the HIC-1-spliced transcripts followed the increase of p53, increase in f transcript coincided with declining p53 and HIC-1 transcript and protein levels. Moreover, the levels of HIC-1 f transcript were not induced by exogenously transfected wild-type p53 in p53-mutated U373MG and p53-null Saos-2 cells, unlike the spliced transcripts that code for full-length HIC-1 protein. These findings suggest a working model wherein the status of f transcript, which is not under direct transcriptional control of wild-type p53, may influence the level of HIC-1 protein in cancer cells.

Tropical pyomyositis (myositis tropicans): current perspective

Tropical pyomyositis, a disease often seen in tropical countries, is characterised by suppuration within skeletal muscles, manifesting as single or multiple abscesses. The most common organism implicated is Staphylococcus aureus. In 20%-50% of cases there is a history of trauma to the affected muscles. Commonly involved muscles are quadriceps, glutei, pectoralis major, serratus anterior, biceps, iliopsoas, gastrocnemius, abdominal and spinal muscles. Early diagnosis is often missed because of lack of specific signs, unfamiliarity with the disease, atypical manifestations, and a wide range of differential diagnosis. Diagnostic techniques like ultrasound and computed tomography/magnetic resonance imaging are very useful in diagnosis. The diagnosis is confirmed either by biopsy or aspiration of pus from the affected muscles. The initial antibiotic of choice is cloxacillin. Incision and drainage are important components of management. Treatment for Gram negative or anaerobic organisms should be instituted, whenever indicated. Physicians should become more familiar with this potentially life threatening but curable infective disease entity.

Knowledge and use of evidence-based nutrition: a survey of paediatric dietitians

OBJECTIVE

To survey paediatric dietitians' knowledge and use of evidence-based nutrition (EBN).

DESIGN

Cross-sectional survey using reply-paid questionnaires.

SUBJECTS

Paediatric dietitians in Australian teaching hospitals.

MAIN OUTCOME MEASURES

Age, sex, appointment, clinical practice, research activities; attitudes to, training in and use of EBN; and perceived barriers to use of EBN.

STATISTICAL ANALYSIS

Data were analysed using descriptive statistics (SPSS).

RESULTS

Fifty-nine (86%) of 69 questionnaires were returned. Most (97%) dietitians were women working full-time (63%), mean age 37 years (+/-9 SD). Most (75%) dietitians encountered knowledge gaps less than five times per week and most (87%) questions related to therapy. The majority (95%) performed their own literature searches, less than five times per month. All had access to >or=1 electronic literature databases including Medline (n = 58, 98%), Cochrane Library (n = 44, 75%) and CINAHL (n = 35, 59%). Information sources used most often were Medline and consultation with colleagues. Reported barriers to using EBN were lack of time (n = 53, 90%) or lack of skills for critical appraisal of published articles (n = 51, 86%) or literature searching (n = 48, 81%). While 53 (90%) believed in an evidence-based approach, 43 (73%) either did not practise EBN or rated themselves as beginners.

CONCLUSION

Most dietitians favoured evidence-based practice, but reported lack of time, skills or rapid access to electronic databases as barriers to its practice.

Transcription of human cathepsin L mRNA species hCATL B from a novel alternative promoter in the first intron of its gene

Cathepsin L is a lysosomal cysteine protease over-expressed in malignancy. It is very potent in degrading collagen, elastin, laminin and other components of the basement membrane and therefore, has been implicated in tumor invasion and metastasis. Two mRNA species, hCATL A and hCATL B, which contain an identical open reading frame and different 5'UTRs, were demonstrated to be encoded by the same gene located on chromosome 9q21-22. We have previously cloned and characterized the promoter responsible for the transcription of hCATL A (hCATL A promoter). However, it was not clear whether hCATL B is a splice variant of hCATL A or transcribed from a different promoter. In the present study, we demonstrate for the first time that hCATL B is transcribed from an alternate promoter (hCATL B promoter) located in the first intron of hCATL. This TATA-less promoter initiates transcription from two cytosine nucleotides present 191 and 367 bases upstream to the translation start codon. Deletion analysis revealed that the core promoter region lies upstream to these transcription initiation sites. This region contains several putative transcription factor-binding sites like AP-1, AP-4, GATA-1, Lmo2, NF-kappa B, MZF-1, NF-AT, etc. In U-87 MG cells, hCATL B promoter exhibits at least six times less activity than our previously characterized hCATL A promoter. However, this promoter is significantly more active in malignantly transformed cells as compared to its activity in untransformed cells. Thus, our results conclusively demonstrate that hCATL B mRNA is transcribed from an alternate promoter. Increased transcriptional activity from this promoter contributes to the elevated cathepsin L expression in transformed cells.

Reduced endocytosis and altered lysosome function in cisplatin-resistant cell lines

We isolated human KB adenocarcinoma cisplatin-resistant (CP-r) cell lines with multidrug-resistance phenotypes because of reduced accumulation of cisplatin and other cytotoxic compounds such as methotrexate and heavy metals. The uptake of horseradish peroxidase (HRPO) and Texas Red dextran was decreased several-fold in KB-CP-r cells, indicating a general defect in fluid-phase endocytosis. In contrast, although EGF receptors were decreased in amount, the kinetics of EGF uptake, a marker of receptor-mediated endocytosis, was similar in sensitive and resistant cells. However, 40-60% of the (125)I-EGF released into the medium after uptake into lysosomes of KB-CP-r cells was TCA precipitable as compared to only 10% released by sensitive cells. These results indicate inefficient degradation of internalised (125)I-EGF in the lysosomes of KB-CP-r cells, consistent with slower processing of cathepsin L, a lysosomal cysteine protease. Treatment of KB cells by bafilomycin A(1), a known inhibitor of the vacuolar proton pump, mimicked the phenotype seen in KB-CP-r cells with reduced uptake of HRPO, (125)I-EGF, (14)C-carboplatin, and release of TCA precipitable (125)I-EGF. KB-CP-r cells also had less acidic lysosomes. KB-CP-r cells were crossresistant to Pseudomonas exotoxin, and Pseudomonas exotoxin-resistant KB cells were crossresistant to cisplatin. Since cells with endosomal acidification defects are known to be resistant to Pseudomonas exotoxin and blocking of endosomal acidification mimics the CP-r phenotype, we conclude that defective endosomal acidification may contribute to acquired cisplatin resistance.