Extremely oligotrophic and complex-carbon-degrading microaerobic bacteria from Arabian Sea oxygen minimum zone sediments

Sediments underlying marine hypoxic zones are huge sinks of unreacted complex organic matter, where despite acute O2 limitation, obligately aerobic bacteria thrive, and steady depletion of organic carbon takes place within a few meters below the seafloor. However, little knowledge exists about the sustenance and complex carbon degradation potentials of aerobic chemoorganotrophs in these sulfidic ecosystems. We isolated and characterized a number of aerobic bacterial chemoorganoheterotrophs from across a ~ 3 m sediment horizon underlying the perennial hypoxic zone of the eastern Arabian Sea. High levels of sequence correspondence between the isolates' genomes and the habitat's metagenomes and metatranscriptomes illustrated that the strains were widespread and active across the sediment cores explored. The isolates catabolized several complex organic compounds of marine and terrestrial origins in the presence of high or low, but not zero, O2. Some of them could also grow anaerobically on yeast extract or acetate by reducing nitrate and/or nitrite. Fermentation did not support growth, but enabled all the strains to maintain a fraction of their cell populations over prolonged anoxia. Under extreme oligotrophy, limited growth followed by protracted stationary phase was observed for all the isolates at low cell density, amid high or low, but not zero, O2 concentration. While population control and maintenance could be particularly useful for the strains' survival in the critically carbon-depleted layers below the explored sediment depths (core-bottom organic carbon: 0.5-1.0% w/w), metagenomic data suggested that in situ anoxia could be surmounted via potential supplies of cryptic O2 from previously reported sources such as Nitrosopumilus species.

Development and Evaluation of an Eco-Friendly Hand Sanitizer Formulation Valorized from Fruit Peels

Hand sanitizer usage has proven to be a common and practical method for reducing the spread of infectious diseases which can be caused by many harmful pathogens. There is a need for alcohol-free hand sanitizers because most hand sanitizers on the market are alcohol-based, and regular use of them can damage the skin and can be hazardous. India is the world's largest producer of fruits and one of the major problems after fruit consumption is their peels, causing waste management problems and contributing to the formation of greenhouse gases leading to air pollution and adding to the problem of climate change. Valorization of such wastes into other value-added products and their incorporation into formulations of eco-friendly alcohol-free hand sanitizers would solve these issues, save the environment, benefit the society, and help in achieving the sustainable development goals. Thus, this research focuses on formulating an effective natural alcohol-free hand sanitizer that harnesses the antimicrobial properties of the various types of bioactive components found in fruit peels of pomegranate, sweet lime, and lemon. The peel extracts and the formulated sanitizer proved considerable antimicrobial activity against the pathogenic Escherichia coli and hand microflora. Molecular docking was also applied to examine ligand-protein interaction patterns and predict binding conformers and affinity of the sanitizer phytocompounds towards target proteins in COVID-19, influenza, and pneumonia viruses. The binding affinities and the protein-ligand interactions virtual studies revealed that the sanitizer phytocompounds bind with the amino acids in the target proteins' active sites via hydrogen bonding interactions. As a result, it is possible to formulate a natural, alcohol-free hand sanitizer from fruit peels that is effective against pathogenic germs and viruses using the basic structure of these potential findings.

Dynamic study of small toxic hydrophobic proteins PepA1 and PepG1 of Staphylococcus aureus

Toxin-antitoxin (TA) systems are small genetic elements which encode toxin proteins that interfere with vital cellular functions. PepA1 and PepG1 toxin proteins, known also as SprA1 and SprG1, are type I TA. In Staphylococcus aureus (S. aureus), their expression without the antitoxin counterparts (SprA1_AS and SprF1), is lethal to the pathogen. Molecular Dynamics (MD) simulation was performed for PepA1 and PepG1 to understand their dynamic state, conformational changes, and their toxicity. The protein structures were constructed and used for MD simulation and the conformational changes, stability, flexibility, fluctuations, hydrophobicity, and role of their dynamic state on function prediction were studied extensively by GROMACS MD simulation analysis tools. In silico study indicated that the PepA1 and PepG1 proteins change their structural conformation from an open to closed state where PepA1 conformational changes were faster (10 ns) than PepG1 (20 ns) while PepG1 exerted more stability and flexibility than PepA1. According to SASA values, PepG1 is more hydrophobic than the PepA1 and forms fewer hydrogen bonds than PepA1. The in vivo study with PepA1 and PepG1 proteins provided evidence that both the conformation changes between the open and closed states and the amino acid sequence are crucial for peptide toxicity.

Role of membrane proteins in bacterial resistance to antimicrobial peptides

Several natural antimicrobial peptides (AMPs), including the novel semisynthetic lipoglycopeptide antibiotics telavancin, dalbavancin, and oritavancin, have been approved for clinical use to address the growing problem of multiple antibiotic-resistant Gram-positive bacterial infections. Nevertheless, the efficacy of these antibiotics has already been compromised. The SARS-CoV-2 pandemic led to the increased clinical use of all antibiotics, further promoting the development of bacterial resistance. Therefore, it is critical to gain a deeper understanding of the role of resistance mechanisms to minimize the consequential risks of long-term antibiotic use and misuse. Here, we summarize for the first time the current knowledge of resistance mechanisms that have been shown to cause resistance to clinically used AMPs, with particular focus on membrane proteins that have been reported to interfere with the activity of AMPs by affecting the binding of AMPs to bacteria.

34S enrichment as a signature of thiosulfate oxidation in the "Proteobacteria"

Kinetics of thiosulfate oxidation, product and intermediate formation, and 34S fractionation, were studied for the members of Alphaproteobacteria Paracoccus sp. SMMA5 and Mesorhizobium thiogangeticum SJTT, the Betaproteobacteria member Pusillimonas ginsengisoli SBO3, and the Acidithiobacillia member Thermithiobacillus sp. SMMA2, during chemolithoautotrophic growth in minimal salts media supplemented with 20 mM thiosulfate. The two Alphaproteobacteria oxidized thiosulfate directly to sulfate, progressively enriching the end-product with 34S; Δ34Sthiosulfate-sulfate values recorded at the end of the two processes (when no thiosulfate was oxidized any further) were -2.9‰ and -3.5‰, respectively. Pusillimonas ginsengisoli SBO3 and Thermithiobacillus sp. SMMA2, on the other hand, oxidized thiosulfate to sulfate via tetrathionate intermediate formation, with progressive 34S enrichment in the end-product sulfate throughout the incubation period; Δ34Sthiosulfate-sulfate, at the end of the two processes (when no further oxidation took place), reached -3.5‰ and -3.8‰, respectively. Based on similar 34S fractionation patterns recorded previously during thiosulfate oxidation by strains of Paracoccus pantotrophus, Advenella kashmirensis and Hydrogenovibrio crunogenus, it was concluded that progressive reverse fractionation, enriching the end-product sulfate with 34S, could be a characteristic signature of bacterial thiosulfate oxidation.

Preferential attraction of different colours of light emitting diodes for Culicoides species in West Bengal, India

The preferential attraction of adult Culicoides (Diptera: Ceratopogonidae) to specific wavelengths was studied in West Bengal, India. A total of 280 collections were made with suction light traps fitted with various colours of light emitting diodes (LEDs) placed at cattle sheds during June, August and November in 2017. In addition, the numbers that have been collected in the evening and morning were compared. Locally manufactured suction light traps fitted with ultra violet (UV), blue, green, yellow, pink, red and white LEDs were compared. UV light attracted the highest number of midges followed by blue and then green LED. Culicoides peregrinus Kieffer and Culicoides oxystoma Kieffer were the most abundant followed by Culicoides fulvus Sen and Das Gupta, Culicoides innoxius Sen and Das Gupta, Culicoides anophelis Edwards and Culicoides huffi Causey. The species composition remained similar across the wavelengths. Although significant variations in midge population have been observed across the months, no significant difference in dusk and dawn abundance was noticed. The females showed a mixed population with less parous individuals.

Algal metabolites: An inevitable substitute for antibiotics

Antibiotic resistance is rising at a pace that is difficult to cope with; circumvention of this issue requires fast and efficient alternatives to conventional antibiotics. Algae inhabit a wide span of ecosystems, which contributes to their ability to synthesize diverse classes of highly active biogenic metabolites. Here, for the first time, we reviewed all possible algal metabolites with broad spectra antibacterial activity against pathogenic bacteria, including antibiotic-resistant strains, and categorized different metabolites of both freshwater and marine algae, linking them on the basis of their target sites and mechanistic actions along with their probable nanoconjugates. Algae can be considered a boon for novel drug discovery in the era of antibiotic resistance, as various algal primary and secondary metabolites possess potential antibacterial properties. The diversity of these metabolites from indigenous sources provides a promising gateway enabling researchers and pharmaceutical companies to develop novel nontoxic, cost-effective and highly efficient antibacterial medicines.

Aerobic microbial communities in the sediments of a marine oxygen minimum zone

The ecology of aerobic microorganisms is never explored in marine oxygen minimum zone (OMZ) sediments. Here we reveal aerobic bacterial communities along ∼3 m sediment-horizons of the eastern Arabian Sea OMZ. Sulfide-containing sediment-cores retrieved from 530 mbsl (meters beneath the sea-level) and 580 mbsl were explored at 15–30 cm intervals, using metagenomics, pure-culture-isolation, genomics and metatranscriptomics. Genes for aerobic respiration, and oxidation of methane/ammonia/alcohols/thiosulfate/sulfite/organosulfur-compounds, were detected in the metagenomes from all 25 sediment-samples explored. Most probable numbers for aerobic chemolithoautotrophs and chemoorganoheterotrophs at individual sample-sites were up to 1.1 × 10⁷ (g sediment)^-1. The sediment-sample collected from 275 cmbsf (centimeters beneath the seafloor) of the 530-mbsl-core yielded many such obligately aerobic isolates belonging to Cereibacter, Guyparkeria, Halomonas, Methylophaga, Pseudomonas and Sulfitobacter which died upon anaerobic incubation, despite being provided with all possible electron acceptors and fermentative substrates. High percentages of metatranscriptomic reads from the 275 cmbsf sediment-sample, and metagenomic reads from all 25 sediment-samples, matched the isolates’ genomic sequences including those for aerobic metabolisms, genetic/environmental information processing and cell division, thereby illustrating the bacteria's in-situ activity, and ubiquity across the sediment-horizons, respectively. The findings hold critical implications for organic carbon sequestration/remineralization, and inorganic compounds oxidation, within the sediment realm of global marine OMZs.

Abundance, diversity and temporal activity of adult Culicoides spp. associated with cattle in West Bengal, India

Relative abundance, species composition and temporal activity of Culicoides midges were studied for a period of 2 years (2012-2014) using suction ultra violet light traps at two sites located in the agriculture heartland of West Bengal, India. Surveillance in close proximity to cattle recorded predominance of five species with C oxystoma and C. peregrinus as the most dominant species followed by C. fulvus, C. innoxius and C. anophelis. The temporal activity of midges was investigated for seven consecutive nights at one site in August-September, 2012 and the predominant species was Culicoides oxystoma followed by Culicoides peregrinus. All of the species exhibited crepuscular activity with their flight activity increasing from dusk to dawn. Engorged adults constituted dominant age group in collections. Studies on population ecology of the adults midges are of considerable importance predicting for the epidemicity of midge-borne diseases in cattle.

Characterization and in vitro Analysis of Probiotic-Derived Peptides Against Multi Drug Resistance Bacterial Infections

An inexorable switch from antibiotics has become a major desideratum to overcome antibiotic resistance. Bacteriocin from Lactobacillus casei, a cardinal probiotic was used to design novel antibacterial peptides named as Probiotic Bacteriocin Derived and Modified (PBDM) peptides (PBDM1: YKWFAHLIKGLC and PBDM2: YKWFRHLIKKLC). The loop-shaped 3D structure of peptides was characterized in silico via molecular dynamics simulation as well as biophysically via spectroscopic methods. Thereafter, in vitro results against multidrug resistant bacterial strains and hospital samples demonstrated the strong antimicrobial activity of PBDM peptides. Further, in vivo studies with PBDM peptides showed downright recovery of balb/c mice from Vancomycin Resistant Staphylococcus aureus (VRSA) infection to its healthy condition. Thereafter, in vitro study with human epithelial cells showed no significant cytotoxic effects with high biocompatibility and good hemocompatibility. In conclusion, PBDM peptides displayed significant antibacterial activity against certain drug resistant bacteria which cause infections in human beings. Future analysis are required to unveil its mechanism of action in order to execute it as an alternative to antibiotics.

A Novel Ruthenium Based Coordination Compound Against Pathogenic Bacteria

The current epidemic of antibiotic-resistant infections urges to develop alternatives to less-effective antibiotics. To assess anti-bacterial potential, a novel coordinate compound (RU-S4) was synthesized using ruthenium-Schiff base-benzimidazole ligand, where ruthenium chloride was used as the central atom. RU-S4 was characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. Antibacterial effect of RU-S4 was studied against Staphylococcus aureus (NCTC 8511), vancomycin-resistant Staphylococcus aureus (VRSA) (CCM 1767), methicillin-resistant Staphylococcus aureus (MRSA) (ST239: SCCmecIIIA), and hospital isolate Staphylococcus epidermidis. The antibacterial activity of RU-S4 was checked by growth curve analysis and the outcome was supported by optical microscopy imaging and fluorescence LIVE/DEAD cell imaging. In vivo (balb/c mice) infection model prepared with VRSA (CCM 1767) and treated with RU-S4. In our experimental conditions, all infected mice were cured. The interaction of coordination compound with bacterial cells were further confirmed by cryo-scanning electron microscope (Cryo-SEM). RU-S4 was completely non-toxic against mammalian cells and in mice and subsequently treated with synthesized RU-S4.

Thermal neutron-induced γ-ray background in 124Sn

The thermal neutron-induced gamma-ray background in ¹²⁴Sn is investigated in connection with neutrinoless double beta decay (0νββ) studies in ¹²⁴Sn. For this purpose, a 99.26% enriched ¹²⁴Sn sample was irradiated with a thermal neutron fluence of 3×10¹⁵/cm² in the Dhruva reactor at the Bhabha Atomic Research Centre, Mumbai. The gamma ray spectra of the irradiated sample were measured in a low background counting setup to study both long-lived and short-lived activities. The present data give an independent measurement of the half-life of ¹²⁵Sn*(32⁺) and ¹²⁵Sn(112^-) as 10.01(8) min and 9.63(2) d, respectively. The impact of the observed high-energy gamma rays and the residual activity due to ¹²⁵Sb, on the background in the region of interest around the Q_ββ value of ¹²⁴Sn (~2.291 MeV) is discussed.

Peptide-Carbon Quantum Dots conjugate, Derived from Human Retinoic Acid Receptor Responder Protein 2, against Antibiotic-Resistant Gram Positive and Gram Negative Pathogenic Bacteria

Antibiotic-resistant bacterial infections have become global issues for public health, which increases the utter need to develop alternatives to antibiotics. Here, the HSER (Homo sapiens retinoic acid receptor) peptide was designed from retinoic acid receptor responder protein 2 of Homo sapiens, and was conjugated with synthesized CQDs (carbon quantum dots) for enhanced antibacterial activity in combination, as individually they are not highly effective. The HSER–CQDs were characterized using spectrophotometer, HPLC coupled with electrospray-ionization quadrupole time-of-flight mass spectrometer (ESI–qTOF) mass spectrometer, zeta potential, zeta size, and FTIR. Thereafter, the antibacterial activity against Vancomycin-Resistant Staphylococcus aureus (VRSA) and Escherichia coli (carbapenem resistant) was studied using growth curve analysis, further supported by microscopic images showing the presence of cell debris and dead bacterial cells. The antibacterial mechanism of HSER–CQDs was observed to be via cell wall disruption and also interaction with gDNA (genomic DNA). Finally, toxicity test against normal human epithelial cells showed no toxicity, confirmed by microscopic analysis. Thus, the HSER–CQDs conjugate, having high stability and low toxicity with prominent antibacterial activity, can be used as a potential antibacterial agent.

Study of the effect of external noise pickups on the performance of a cryogenic bolometer

This paper reports the detailed noise characterization, investigation of various noise sources, and its mitigation to improve the performance of a cryogenic bolometer detector for the TIN.TIN experiment. The noise spectrum has been measured for a sapphire bolometer test setup with an indigenously developed neutron transmutation doped Ge sensor in the cryogen free dilution refrigerator system at Mumbai. The effect of external noise, arising either from ground loops in the system or from the diagnostic and control electronics of the cryostat, on the performance of the bolometer is assessed. A systematic comparison of the influence of different noise pickups on the bolometer resolution is also presented. The best-achieved resolution (σ_E) at 15 mK is ∼15 keV for heater pulses and appears to be mainly limited by the noise due to the pulse tube cryocooler.

Novel vancomycin-peptide conjugate as potent antibacterial agent against vancomycin-resistant Staphylococcus aureus

Background

Increase in vancomycin (Van)-resistant bacterial strains including vancomycin-resistant Staphylococcus aureus (VRSA) and lack of new effective antibiotics have become a formidable health problem.

Materials and methods

We designed a new conjugate composed of Van and a peptide Hecate (Hec; Van/Hec), and its potential antimicrobial activity was evaluated.

Results

Results from disk diffusion test, time-kill assay, determination of minimum inhibitory concentration (MIC), microscopy, and comet assay showed strong antimicrobial effects of Van/Hec against wild-type, methicillin-resistant Staphylococcus aureus (MRSA) and VRSA. Microscopy revealed that the exposure to Van/Hec results in disruption of bacterial cell integrity in all tested strains, which was not observed in case of Van or Hec alone.

Conclusion

Overall, we showed that the preparation of conjugates from antibiotics and biologically active peptides could help us to overcome the limitation of the use of antibiotic in the treatment of infections caused by multidrug-resistant bacteria.

Long-Term Consequences of Complex Living Renal Donation: Is It Safe?

INTRODUCTION

As there is a paucity of literature regarding the long-term outcomes of complex living donors, we conducted this study to assess the effect of kidney donation on the complex living kidney donor.

MATERIALS AND METHODS

This retrospective study was conducted in Narayan Health Hospital, Kolkata, Eastern India. The cohort consisted of complex living kidney donors who donated kidneys between the years 2007 and 2012. All donors were 60 years old or older, or were younger than 60 years and had comorbidities like hypertension and obesity. After a minimum follow-up of 5 years, all donors underwent evaluation. Data pertaining to hypertension, new-onset diabetes, body mass index (BMI), estimated glomerular filtration rate (eGFR) and albuminuria, and cardiac events were compared from the time of donation till 5 years post-transplant.

RESULTS AND DISCUSSION

We found a statistically significant increase in blood pressure, number of antihypertensives used, and mean BMI at follow-up. Diabetes mellitus was developed in 22.3% of donors. The mean GFR also decreased significantly at follow-up. There were 42 elderly donors (≥60 years) and 23 ≤ 59 years of age. There was a significant fall of eGFR in both groups, but the percentage fall was similar in both groups. A significant percentage of donors developed proteinuria, the majority being hypertensives.

CONCLUSION

Procurement of kidneys from marginal donors should be done cautiously, and donors should be assessed for morbidity and mortality in the future, as we found a statistically significant deterioration in renal function, blood pressure, and BMI over long-term follow-up.

Enhanced carbon-sulfur cycling in the sediments of Arabian Sea oxygen minimum zone center

Biogeochemistry of oxygen minimum zone (OMZ) sediments, which are characterized by high input of labile organic matter, have crucial bearings on the benthic biota, gas and metal fluxes across the sediment-water interface, and carbon-sulfur cycling. Here we couple pore-fluid chemistry and comprehensive microbial diversity data to reveal the sedimentary carbon-sulfur cycle across a water-depth transect covering the entire thickness of eastern Arabian Sea OMZ, off the west coast of India. Geochemical data show remarkable increase in average total organic carbon content and aerial sulfate reduction rate (JSO42-) in the sediments of the OMZ center coupled with shallowing of sulfate methane transition zone and hydrogen sulfide and ammonium build-up. Total bacterial diversity, including those of complex organic matter degraders, fermentative and exoelectrogenic bacteria, and sulfate-reducers (that utilize only simple carbon compounds) were also found to be highest in the same region. The above findings indicate that higher organic carbon sequestration from the water-columns (apparently due to lower benthic consumption, biodegradation and biotransformation) and greater bioavailability of simple organic carbon compounds (apparently produced by fermetative microflora of the sediments) are instrumental in intensifying the carbon-sulfur cycle in the sediments of the OMZ center.

Salinity stratification controlled productivity variation over 300 ky in the Bay of Bengal

The unique hydrographic setting of the Bay of Bengal (BoB) makes it an ideal tropical marine system to study the influence of regional and global forcings on productivity and [CO2aq] through the late quaternary. Enormous fresh water flux into the BoB and consequent salinity stratification significantly weaken the convective mixing and wind driven processes which are commonly responsible for transport of nutrients to the euphotic zone driving primary productivity. Here we present a high resolution organic carbon-CaCO3 MAR and δ13CTOC records for the last 300 ky from the BoB. The results show significant productivity variation at marine isotope sub-stages and millennial timescales. Colder sub-stages and stadials (Dansgard-Oeschger cycle) show a boost in productivity which may be attributed to thinning of low salinity cap, thereby facilitating efficient nutrient transport across the euphotic zone by the combination of wind driven processes (entrainment and upwelling), convective mixing and cold core eddies. The [CO2aq] was a net result of global pCO2 variation and regional processes. Our long term high-resolution data indicates a possibility of marked change in productivity/biogeochemistry of BOB in the future due to global warming, thus affecting the coastal economy.

Harlequin Ichthyosis - A Case Report

Harlequin Ichthyosis is a very rare genetic disorder affecting mainly the skin with severe morbidity and mortality. It affects both sexes with incidence of about 1 in 300,000 live births. Autosomal recessive inheritance has been inferred with mutation in ABCA 12 gene identified. Hence, genetic counseling and mutation screening of this gene should be considered in at-risk patients. Death usually occurred in the first 3 months of life due to sepsis, feeding problems and respiratory distress. With improved neonatal care and early introduction of retinoids, its survival rate has increased.

Genotypic variation in carbon fixation, δ13C fractionation and grain yield in seven wheat cultivars grown under well-watered conditions

Biotic carbon (C) sequestration is currently being considered as a viable option for mitigating atmospheric carbon dioxide (CO2) emission, in which photosynthesis plays a significant role. A field experiment was conducted between 2013 and 2015 to investigate the efficiency of seven modern wheat varieties for CO2 fixation, C partitioning, δ13C fractionation in the leaves, and grain yield. A strong correlation between flag leaf photosynthesis and stomatal density (r=0.891) was detected. Photosynthetic efficiency was highest in the variety WH-1021 (28.93µmolm-2s-1). Grain yield was influenced by biomass accumulation in the heads and these were significantly correlated (r=0.530). Our results show that upregulated biomass partitioning to the developing kernels of wheat was inversely proportional to biomass accumulation in the roots, and led to a higher grain yield. These results led us to conclude that identification of a wheat genotype like WH-1021 followed by WH-1080 and WH-711, with higher isotopic discrimination in the flag leaves, stomatal densities, water use and photosynthetic efficiencies along with higher grain yield, can contribute to sustainable agriculture in future climate change situation in India. A yield increment of 9-48% was recorded in WH-1021 over other six tested wheat varieties.

Abstract P1-08-04: SOX9 is a critical regulator of triple-negative breast cancer cell growth and invasion

Background: SRY (Sex Determining Region Y)-related HMG-box (SOX) genes belong to a super-family of genes, which is characterized by a homologous sequence called the HMG-box residing on the Y-chromosome. There are 20 SOX genes present in humans and mice. We performed a siRNA screen of SOX transcription factors, and found that SOX9 was essential for breast cancer cell growth. The SOX9 protein recognizes the sequence CCTTGAG along with other members of the HMG-box class DNA-binding proteins and has been shown to be required for development, differentiation and lineage commitment. Moreover, SOX9 is expressed in adenocarcinomas, and is highly expressed in the most aggressive cancers. Our previous data shows SOX9 is highly expressed in “triple negative breast cancer” (TNBC) than in non-TNBC. Thus, we hypothesized that the SOX9 transcription factor acts as an essential molecule regulating TNBC growth and invasion. To test the hypothesis, we used SOX9-overexpressed, or SOX9-knockdown/knockout breast cancer cell models to determine whether SOX9 is necessary and/or sufficient to regulate TNBC cell proliferation, migration and invasion.

Methods: We measured the cell growth using an automated cell counting assay. Cell migration and invasion were detected by transwell migration & invasion assays in ER-positive (MCF7 and ZR75-1) and ER-negative (MDA231 and MDA468) breast cancer cells. DOX-inducible SOX9-knockout cell lines were established in MDA231, MDA468, and LM2 cell lines using an inducible Cas9-CRISPR system. A SOX9 expressing lentivirus was used to overexpress SOX9, and siRNAs was used to knockdown SOXs in the different breast cancer cells. Protein and mRNA levels of SOX9 in TNBC, non-TNBC, immortalized human breast epithelial cell lines were examined by western blotting and qRT-PCR assay.

Results: Knockdown of SOXs by siRNA caused decreased cell proliferation of MDA231 by ≥50% and of MDA468 by 30%-50% in siSOX4, siSOX6, siSOX9, siSOX10 and siSOX11 treatment groups (but not in siSOX8 and siSOX17 treatment groups). However, in MCF7 and T47D cell lines, treatment with siRNA to these SOX factors did not cause significant cell growth reduction. We demonstrated that SOX9 is more highly expressed in TNBC cells at both the mRNA and protein levels. Knockdown of SOX9 decreased cell migration and invasion of MDA231 to 25% and 50% respectively. The same effect also was observed in MDA468 cells, with approximately a 50% decline in migration and invasion. In SOX9-knockout MDA231, MDA468, and LM2 cells, cell proliferation, migration, and invasion were significantly reduced. In contrast, overexpression of SOX9 in MCF7 and ZR75-1 cells increased cell migration and invasion. We are now conducting in vivo studies to determine the effect of SOX9 on breast cancer cell metastasis.

Conclusion: SOX9 is a critical regulator of TNBC cell proliferation, migration and invasion. These studies suggest that regulating SOX9 transcription factor and its signaling pathway will be a promising therapeutic strategy to treat TNBC and prevent metastasis.

This work was supported by a Susan G. Komen Scientific Advisory Board Grant, SAB1600006 (PB), and a grant from the Breast Cancer Research Foundation 2015-2016 BCRF grant(PB), and by the Charles Cain Endowment (PB).

Citation Format: Ma Y, Shepherd J, Mazumdar A, Zhao D, Bollu L, Hill J, Zhang Y, Brown P. SOX9 is a critical regulator of triple-negative breast cancer cell growth and invasion [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-08-04.

Laboratory rearing of immature Culicoides peregrinus Kieffer, a potential vector of bluetongue virus

Culicoides peregrinus (Kieffer) (Diptera: Ceratopogonidae) was reared from egg to adult using four different combinations of food and substrate (T1: absorbent cotton, mud broth with 2% yeast; T2: 1% agar, mud broth with 2% yeast; T3: absorbent cotton, nutrient broth; T4: absorbent cotton, 2% yeast). Field-collected engorged females exhibited mean fecundity of 82.45 ± 4.00. The highest rate of emergence and largest adults were obtained in T1, and the lowest rate of emergence was observed in T4. Two-way analyses of variance with post hoc Tukey tests showed significant differences in age at pupation, pupal weight and wing length among the various treatments, although the sex ratio was 1 : 1 in all food/substrate combinations. The successful rearing of immature C. peregrinus is an encouraging step towards the establishment of a laboratory colony of this prevalent species associated with livestock.

Isolation of haemolytic bacilli from field-collected Culicoides oxystoma and Culicoides peregrinus: potential vectors of bluetongue virus in West Bengal, India

Two haemolytic bacterial strains of Bacillus pumilus (CU1A, CU1B) and one blood-utilizing strain of Bacillus licheniformis (CU2B) were isolated from relatively low numbers of field-collected females of Culicoides oxystoma and Culicoides peregrinus (Diptera: Ceratopogonidae). A total of 36 females, including 18 of each of C. oxystoma and C. peregrinus (consisting of one and a pool of eight blood-engorged specimens, and one and a pool of eight non-engorged specimens for each species), were tested. In C. oxystoma, all three strains of bacteria were isolated from the one non-engorged, the pool of non-engorged and the pool of blood-engorged females tested, but CU1A and CU2B were not found in the one blood-engorged female tested. In C. peregrinus, all three strains were present in the pool of blood-engorged females. However, the strain CU2B was not found in the pool of non-engorged females. In the one blood-engorged and one non-engorged female tested, CU1A and CU2B were detected. The bacterial strains were identified based on Gram staining, enzyme activity (amylase and protease) and alignment of the 16S rRNA partial gene sequence to that available in the National Center for Biotechnology Information (NCBI) database GenBank. The functional role and significance of these haemolytic and blood-digesting bacteria within the genus Culicoides remain to be determined.

Records of the Genus Paramerina (Diptera: Chironomidae: Tanypodinae) from Eastern Himalaya and Satpura Hill Regions of India

The pupa and the male imago of Paramerina valida n. sp. and the larva of Paramerina inficia Chaudhuri & Debnath are described and illustrated along with a brief re-description of the adult of P. inficia from the Eastern Himalaya and Satpura hill regions of India. A key to the adult males of the Indian species of the genus Paramerina Fittkau is provided. The notes on ecology of the two species are also provided.

PD03-03: Identification of Transcription Factors Critical for the Growth of Basal Breast Cancer

Background: Basal breast cancers are aggressive, poor prognosis tumors that occur commonly in young women and in African American women. Profiling of breast tumor mRNA has demonstrated that there are differences in gene expression between the basal and luminal subtypes of breast cancer. In this study, we identified response elements in the genes that define basal breast cancers, and identified transcription factors that are critical for the growth of basal breast cancer cells.

Materials and Methods: We performed promoter analysis using 4 published microarray studies (PMID: 12829800; PMID: 19435916; PMID: 17157792; PMID: 11562467) to select genes that are highly expressed in basal tumors compared to luminal tumors. For this analysis we selected 61 genes highly expressed in a set of basal tumors in any of the 4 microarray studies. We next used the online tool, CORE_TF, along with the MATCH algorithm minimizing for the sum of false positives and false negatives to identify binding motifs within the promoter (defined from −1 kb to the first exon) of each gene. The frequency of binding motif occurrence for these 61 basal genes was compared to the frequency within the promoters of 3000 randomly selected genes. Significance was tested using an exact binomial test with a cutoff of p<0.05. RNA expression of motif-identified transcription factors was then analyzed in-silico using all 10 datasets in Oncomine™ that contained annotation for triple-negative status. Expression in triple negative samples was compared to expression in non-triple-negative samples with a cutoff of p <0.05. We next performed siRNA knockdown studies to determine whether the identified TFs regulate basal breast cancer growth. Basal and luminal cells transfected with control and specific siRNAs were grown in triplicate and mean cell counts at day 6 were compared.

Results: Promoter analysis identified 24 binding motifs that were over-represented in basal breast tumor genes compared to a random set of 3000 genes. TransFac analysis indicated that 47 transcription factors bind the 24 identified motifs. Oncomine analysis showed that 8 of the 47 transcription factors were significantly more highly expressed in basal as compared to non-basal tumors. Identified transcription factors include FOXC1, FOXM1, CDC5L, E2F3, CEBP and NF-Y. siRNA to FOXM1 in 2 basal breast cell lines reduced growth by >70% after 6 days, whereas, in the luminal cell line MCF7, growth was reduced by 15%.

Discussion: This study identified transcription factors that are highly expressed in basal breast tumors (as compared to non-basal breast tumors). siRNA knockdown studies showed that FOXM1 is critical for basal breast cancer cell growth. These results suggest that transcription factors highly expressed in basal breast cancers may be novel targets for the treatment of this disease.

These studies were supported by a Promise grant from the Susan G. Komen for the Cure (PB, SGH), and by the Norman E. Brinker Award for Research Excellence (PB).

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD03-03.

P4-01-18: AP-1 Blockade Potentiates the Anti-Tumor Effect of Endocrine Treatment and Reverts the Resistant Phenotype in Hormone Receptor-Positive Breast Cancer

Background: Resistance to endocrine therapy is a major clinical issue. The transcription factor AP-1 is a key regulator of cell growth and survival as well as a downstream signaling component of several pathways deregulated in endocrine-resistant breast cancer. We have previously shown that acquired endocrine resistance is associated with increased AP-1 activity. AP-1 has also been shown to interact with and modulate the ER network and transcriptional program, especially under hyperactive growth factor signaling, which is commonly associated with endocrine resistance. We hypothesized that interfering with AP-1 function would circumvent endocrine resistance possibly due to its role in modulating ER transcriptional activity.

Methods and results: We inhibited AP-1 function by a genetic approach. We used two different MCF7 clones stably transfected with a Doxycycline (Dox)-inducible dominant-negative (DN) c-Jun (MCF7/Tet-Off Tam67 clones 62 and 67) and two vector-alone control MCF7 clones. Xenografts of these clones were established in ovariectomized nude mice supplemented with estrogen (E2). Mice were then randomized to continued E2 supplementation (control) or to endocrine therapy with either estrogen deprivation (ED) or tamoxifen (Tam), all in the presence or absence of Dox to induce the DN c-Jun expression. AP-1 blockade in both MCF7/Tet-Off Tam67 clones significantly enhanced sensitivity to Tam by reducing time to tumor size halving (p=.014 and p=.006 for clone 62 and 67, respectively) and time to complete tumor disappearance (p=.001 and p=.0034 for clone 62 and 67, respectively). Similar results were obtained with ED treatment. In addition, AP-1 blockade significantly delayed the onset of Tam resistance by increasing time to tumor size doubling (p=.0028). Furthermore, induction of DN c-Jun resulted in a dramatic shrinkage of growing tumors after long-term Tam treatment, suggesting reversal of endocrine resistance with AP-1 blockade. None of the above effects was observed in control clones upon Dox removal. Interestingly, no significant effect of AP-1 blockade was observed on E2-stimulated tumor growth. IHC analysis showed that AP-1 blockade induced tumor response by reducing proliferation (i.e., decreased % of Ki67- and phospho-Histone 3-positive cells) and by inducing apoptosis (i.e., increased % of cleaved caspase 3/7-positive cells). Bioinformatic analyses were conducted to intersect our MCF7 xenograft/Tam-resistant gene signature and the datasets of genes associated with ER DNA-binding sites obtained by whole-genome ER cistromic analysis under estrogen or epidermal growth factor (EGF) stimulation of MCF7 cells. A significant enrichment of the genes associated with the EGF-unique ER DNA-binding sites was observed within our Tam-resistant signature (p<2E-16). Remarkably, 90% of these DNA binding sites harbored an AP-1 motif.

Conclusions: We show that AP-1 blockade increases tumor sensitivity and circumvents resistance to endocrine therapy, thus warranting the development of AP-1-targeted therapy to improve endocrine treatment outcomes. Overall, we suggest that AP-1 is critical in induction of a switch in the ER transcriptional program and may be a new hallmark of endocrine resistance.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-01-18.

Design of a Catheter-Based Device for Performing Percutaneous Chordal-Cutting Procedures

In this paper we detail the rapid design, fabrication and testing of a percutaneous catheterbased device that is envisioned to enable externally controlled manipulation and cutting of specific chordae tendinae within the heart. The importance of this work is that it (a) provides a means that surgeons may use to alleviate problems associated with some forms of mitral valve regurgitation and (b) demonstrates how a deterministic design process may be used to drive design innovation in medical devices while lowering development cost/time/resources. In the United States alone, approximately 500,000 people develop ischemic or functional MR per year. A chordal cutting procedure and device could allow many patients, who would otherwise be unable to survive open-heart surgery, to undergo a potentially life-saving operation at reduced risk. The design process has enabled us to generate a solution to this problem in a relatively short time. A deterministic design process was used to generate several design concepts and then evaluate and compare each concept based on a set of functional requirements. A final concept to be alpha prototyped was then chosen, optimized, and fabricated. The design process made it possible to make rapid progress during the project and to achieve a device design that worked the first time. This approach is important to medical device design as it reduces engineering effort, cost, and the amount of time spent in iterative design cycles. An overview of the design process will be presented and discussed within the context of a specific case study–the rapid design/fabrication of a chordal cutting device. Experimental results will be used to assess: (i) The performance of the catheter in maneuvering into the heart and grasping various structures. (ii) The effectiveness of the catheter's RF ablation tip at cutting chordae inside of a heart. In the first experiment, the catheter was guided to the basal chordae under direct visualization, which showed that the catheter is capable of successfully grasping a chord. During the second experiment, ultrasound was shown to be a viable method of visualizing the catheter within the heart. During this experiment, once contact between the chord and RF ablator tip was confirmed, the chord was successfully ablated. We will also discuss experiments that are currently underway to visualize the catheter utilizing a Trans-Esophageal Echo probe, as well as imaging the mitral valve from the apex of the heart with a laparoscope so that video of the basal chord being grasped and cut can be acquired on a heart whose anatomical structures are intact. A brief synopsis will then be given of how the design process has been used in research and educational collaborations between MIT and local hospitals.

Single-institution experience with matrix coils in the treatment of intracranial aneurysms: comparison with same-center outcomes with the use of platinum coils

BACKGROUND AND PURPOSE

This study was undertaken to analyze the outcomes and treatment-related complications of the polyglycolic/polylactic acid (PGLA)-coated Matrix platinum coils in the treatment of intracranial aneurysms and compare these results with those derived from the same single-institutional experience with use of uncoated, bare platinum coils.

MATERIALS AND METHODS

In this study, we compared 2 groups of patients in a retrospective fashion. The first group consisted of 70 consecutive patients who underwent 82 aneurysm treatments with Matrix coils during the 14-month period of study, from January 2003 to February 2004. We compared this cohort with 70 consecutive patients who underwent a total of 80 aneurysm treatments with bare platinum coils in the 12 months immediately preceding the use of PGLA-coated coils, from January through December 2002. We then recorded the treatment characteristics, angiographic outcomes, and any complications.

RESULTS

There were similar baseline demographic characteristics between the 2 study groups except in age, anatomic location, and length of follow-up. The overall recurrence rate of aneurysms was 41% among the Matrix-treated group and 32% among the patients treated with bare platinum. Among the 42 patients treated with 100% Matrix, the rate of recurrence was 31%. Of the recurrences, 21% of the Matrix group, 19% of the 100% Matrix group, and 9% of the bare platinum group required retreatment. The overall rate of complications was 10% in the Matrix-treated group and 7% in the bare platinum group. There was not a statistically significant difference in the rate of recurrence of aneurysms or complications between the 2 groups.

CONCLUSIONS

On the basis of our single-center experience, there is insufficient evidence to support the use of Matrix coils over bare platinum coils, given their disadvantages.

A sequential scanning of the immune efficiency in astrocytoma (Grade I to Grade Iii), meningioma and secondary glioma patients with and without therapeutic scheduling

PURPOSE

Glioma induces immune suppression. However, data revealing the immune status in glioma patients with sequential therapeutic interventions is missing. Thus, the study aims at evaluating the sequential immune status of glioma bearing patients (Astrocytoma Grade I to Grade III) receiving conventional therapeutic measures. The results were compared with the immune status of metastatic secondary glioma and meningioma patients where there is minimal immune suppression and the effect of therapeutic intervention on the above score.

METHODS

Functional immune parameters of peripheral blood lymphocytes were assayed by CD2 receptors enumeration through E-rosetting and lymphocyte cytotoxicity assay and assessing the generation of reactive oxygen species by NBT assay of peripheral blood macrophages in patient groups bearing Astrocytoma (Grade I to Grade III), meningioma and secondary glioma.

RESULTS

Patients bearing Astrocytoma (all 3 grades) showed maximum immune suppression as compared to the normal subjects, diseased meningioma controls, and secondary glioma. Therapeutic interventions viz. radiotherapy, surgery and radiotherapy after surgery and chemotherapy could not recover the suppressed activity of the CD2 bearing lymphocytes and that of peripheral blood macrophages. However, therapeutic scheduling could recover the functional activity of the CD8 bearing lymphocytes and the CD56 NK cells from that of tumor bearing patients.

CONCLUSION

Astrocytoma and not meningioma is capable of causing immunesuppression. As the tumor progresses from Grade I to Grade III, a linear reduction in the functional efficacy of immunocytes is seen to occur. Radiotherapy, surgery, and chemotherapy also induces an inhibitory effect towards the host immune system. The inhibitory effect of tumor as well as of therapy were mainly directed towards the CD2 bearing lymphocyte population and the peripheral blood macrophage population.

Frequency of spinal arteriovenous malformations in patients with unexplained myelopathy

The authors reviewed charts of 78 myelopathy patients who underwent spinal angiography for possible arteriovenous malformations (AVMs). Twenty-two patients had an AVM. No neurologic complications from angiography were observed. MRI findings of increased T2 signal or flow voids were strongly associated with AVMs. Spinal angiography should be performed in all patients with unexplained myelopathy after neurologic evaluation and an MRI demonstrating increased T2 signal or flow voids.

Antennal deformities of chironomid larvae and their use in biomonitoring of heavy metal pollutants in the river Damodar of West Bengal, India

Analyses of sediment and water indicate the presence of heavy metal pollutants like lead, zinc, copper, mercury and cadmium of the river Damodar of India. These metals are responsible for causing morphological deformities of antennae and other parts of chironomid larvae. Percentage of deformity correlated positively with the concentrations of Pb in water and sediment (r > 0.6) at the confluence point. A new severity index, SISS((antenna)) has been proposed here to assess deformity at the family or subfamily level.

Genome-wide survey of protein kinases required for cell cycle progression

Cycles of protein phosphorylation are fundamental in regulating the progression of the eukaryotic cell through its division cycle. Here we test the complement of Drosophila protein kinases (kinome) for cell cycle functions after gene silencing by RNA-mediated interference. We observed cell cycle dysfunction upon downregulation of 80 out of 228 protein kinases, including most kinases that are known to regulate the division cycle. We find new enzymes with cell cycle functions; some of these have family members already known to phosphorylate microtubules, actin or their associated proteins. Additionally, depletion of several signalling kinases leads to specific mitotic aberrations, suggesting novel roles for familiar enzymes. The survey reveals the inter-digitation of systems that monitor cellular physiology, cell size, cellular stress and signalling processes with the basic cell cycle regulatory machinery.

Dynamic chromatin remodeling on the HER2 promoter in human breast cancer cells

Deregulation of the HER2 oncogene occurs in 30% of human breast cancers and correlates with poor prognosis and increased propensity for metastasis. Since the molecular basis of HER2 overexpression in human cancers is not known, we sought to determine whether chromatin remodeling pathways are involved in the regulation of HER2 expression. We report that compared with breast cancer cells expressing a low level of HER2, HER2-overexpressing breast cancer cells contained significantly higher levels of acetylated and phosphorylated histone H3, and acetylated histone H4 associated with the HER2 promoter. Decreased recruitment of histone deacetylases in the promoter is also noted in the HER2-overexpressing cell. The association of acetylated histone H4 with HER2 gene chromatin and HER2 expression in breast cancer cells was upregulated by an inhibitor of histone deacetylases. Treatment with histone deacetylase inhibitor also reduced the association of histone deacetylase-1 and -2 with the HER2 promoter. In addition, the tumor promoters 12-O-tetradecanoylphorbol-13-acetate and okadaic acid stimulated the association of phosphorylated histone H3 on serine 10 with the HER2 promoter and also stimulated HER2 expression. These findings identify histone acetylation and histone phosphorylation as novel regulatory modifications that target HER2 gene chromatin, and suggest that elevated levels of these chromatin-relaxing components in the vicinity of the HER2 gene promoter may constitute an important non-genomic mechanism of HER2 overexpression in human breast cancer.

Molecular cloning and characterization of PELP1, a novel human coregulator of estrogen receptor alpha

Nuclear hormone receptors (NRs) are transcription factors whose activity is regulated by ligands and by coactivators or corepressors. We report the characterization of a new NR coregulator: proline-, glutamic acid-, leucine-rich protein 1 (PELP1), a novel human protein that comprises 1,282 amino acids and is localized on chromosome 17. The primary structure of PELP1 consists of several motifs present in most transcriptional regulators including nine NR-interacting boxes (LXXLL motifs), a zinc finger, and glutamic acid- and proline-rich regions. We demonstrate that PELP1 is a coactivator of estrogen receptor alpha (ERalpha). PELP1 enhances 17beta-estradiol-dependent transcriptional activation from the estrogen response element in a dose-dependent manner. PELP1 interacts with ERalpha and also with general transcriptional coactivators p300 and cAMP response element-binding protein-binding protein. PELP1 was differentially expressed in various human and murine tissues with the highest expression levels in the testes, mammary glands, and brain. We also provide evidence supporting the developmental regulation of PELP1 expression in murine mammary glands, the detectable expression of PELP1 in human mammary cancer cell lines, and the enhanced expression of PELP1 in human breast tumors. These findings suggest that PELP1 is a novel coregulator of ERalpha and may have a role in breast cancer tumorigenesis.

Noncommutativity in space and primordial magnetic field

In this paper we show that noncommutativity in spatial coordinates can generate magnetic field in the early Universe on a horizon scale. The strength of such a magnetic field depends on the number density of massive charged particles present at a given moment. This allows us to trace back the temperature dependence of the noncommutativity scale from the bounds on primordial magnetic field coming from nucleosynthesis.

Evaluation of the predictors of choledocholithiasis: comparative analysis of clinical, biochemical, radiological, radionuclear, and intraoperative parameters

This prospective study was performed to assess the predictive ability of the various indicators of common bile duct (CBD) calculi, individually or in combination, by analyzing 88 patients with gallstone disease. The patients were classified into two groups according to the presence of 10 predefined criteria. Of 53 patients with one or more risk factors (group 2), 26 harbored CBD calculi; none of 35 patients with no risk factors (group 1) had CBD stones. Jaundice correlated best, with a sensitivity of 69%; and pancreatitis had the lowest sensitivity (12%). Elevated serum bilirubin and alkaline phosphatase levels correlated better than liver enzymes and serum amylase. The sensitivity and negative predictive value of cholescintigraphy scanning for diagnosing CBD calculi were better than those of ultrasonography, the sensitivity being 84% versus 50% and the negative predictive value 95% versus 82%. Endoscopic retrograde cholangiopancreaticography was successful in 94% of the patients, and CBD calculi were diagnosed in 74%. Moreover, peroperative cholangiography was 100% sensitive with no false-positive results. Ultimately, a palpable stone at surgery was the best predictor. When all the criteria were analyzed, it was found that as the number of criteria increased so did the percentage of patients harboring CBD calculi.

The role of endoscopic procedures in the management of postcholecystectomy and posttraumatic biliary leak

Endoscopic retrograde cholangiopancreatography (ERCP) is an important tool in the evaluation of the biliary system. It not only diagnoses the site of biliary leak following bile duct injury, but it also acts as a therapeutic modality to allow interventional procedures such as sphincterotomy, nasobiliary drainage, or stent placement to be performed. The present study was carried out to evaluate the role of endoscopic management of biliary leak, following either liver trauma or cholecystectomy. Of a total 21 patients with bile leak following liver trauma and biliary surgery, 20 were managed by various endoscopic procedures. In the postcholecystectomy group, ERCP revealed a cystic duct leak in 9 patients and common bile duct injury in 6 patients. These complications were managed by sphincterotomy alone in 2 patients, by nasobiliary drainage alone in 4 patients, by sphincterotomy and nasobiliary drainage in 8 patients, and by sphincterotomy and stent placement in 1 patient. Posttraumatic biliary fistula was successfully managed by performing sphincterotomy followed by the placement of nasobiliary drainage in all of five patients who had suffered trauma injury.

Alternative splicing of the imprinted candidate tumor suppressor gene ZAC regulates its antiproliferative and DNA binding activities

ZAC encodes a zinc finger protein with antiproliferative activity, is maternally imprinted and is a candidate for the tumor suppressor gene on 6q24. ZAC expression is frequently lost in breast and ovary tumor-derived cell lines and down-regulated in breast primary tumors. In this report, we describe ZACDelta2, an alternatively spliced variant of ZAC lacking the sequence encoding the two N-terminal zinc fingers. Messenger RNAs encoding ZAC or ZACDelta2 were equally abundant and both proteins were nuclear. ZACDelta2 displayed an improved transactivation activity and an enhanced affinity for a ZAC binding site, suggesting that the two N-terminal zinc fingers negatively regulated ZAC binding to its target DNA sequences. Both proteins were equally efficient in preventing colony formation, indicating similar overall antiproliferative activities. However, these activities resulted from a differential regulation of apoptosis vs cell cycle progression since ZACDelta2 was more efficient at induction of cell cycle arrest than ZAC, whereas it was the reverse for apoptosis induction. Hence, these data further underline that ZAC gene is critically controlled, both at the transcriptional level through imprinting and at the functional level through alternative splicing.

A three-dimensional and temporo-spatial model to study invasiveness of cancer cells by heregulin and prostaglandin E2

To study the temporal expression of motile structures and protease activity during colon cancer cell invasion by heregulin-beta1 (HRG) and prostaglandin E2 (PGE2), we have developed a three-dimensional spatial model system. HRG and PGE2 each induced the formation of well-organized, three-dimensional structures with empty spaces in the center and stimulated the expression of urokinase plasminogen activator (uPA) with differential localization of membrane-bound uPA at the focal adhesion points and leading edges of the motile cells. A specific cyclooxygenase-2 inhibitor blocked the formation of three-dimensional luminal glandular structures induced by HRG but did not block those induced by PGE2. A specific antagonist of uPA receptor completely blocked the formation of these luminal glandular structures induced by PGE2 and HRG. These findings suggest that HRG-mediated increased invasiveness of colon cancer cells is augmented at least in part by induction of PGE2 and uPA, and this augmentation may involve the formation of three-dimensional invasive structures via the uPA pathway. In addition, the three-dimensional model system presented here may have a wider application to screen the effects of therapeutic compounds and biomolecules on different spatial aspects of colonic biology, including cell growth, motility, invasion, survival, and apoptosis.