A RUNX1/ETO-SKP2-CDKN1B axis regulates expression of telomerase in t (8;21) acute myeloid leukemia

The fusion oncoprotein RUNX1/ETO which results from the chromosomal translocation t (8;21) in acute myeloid leukemia (AML) is an essential driver of leukemic maintenance. We have previously shown that RUNX1/ETO knockdown impairs expression of the protein component of telomerase, TERT. However, the underlying molecular mechanism of how RUNX1/ETO controls TERT expression has not been fully elucidated. Here we show that RUNX1/ETO binds to an intergenic region 18 kb upstream of the TERT transcriptional start site and to a site located in intron 6 of TERT. Loss of RUNX1/ETO binding precedes inhibition of TERT expression. Repression of TERT expression is also dependent on the destabilization of the E3 ubiquitin ligase SKP2 and the resultant accumulation of the cell cycle inhibitor CDKN1B, that are both associated with RUNX1/ETO knockdown. Increased CDKN1B protein levels ultimately diminished TERT transcription with E2F1/Rb involvement. Collectively, our results show that RUNX1/ETO controls TERT expression directly by binding to its locus and indirectly via a SKP2-CDKN1B-E2F1/Rb axis.

In vitro bio-interaction responses and hemocompatibility of nano-based linear low-density polyethylene polymer embedded with heterogeneous TiO2/ZnO nanocomposites for biomedical applications

An innovative nano-base polymer that scavenges radicals and reactive oxygen species exhibits potential antibacterial properties, which are crucial in the biomedical field, particularly in reducing nosocomial infections. However, the safety of this nano-based polymer, which has direct contact with the human system, has not been fully understood. The present study investigated the cytocompatibility and hemocompatibility responses of linear low-density polyethylene polymer (LLDPE) embedded with difference ratios of heterogeneous TiO₂/ZnO nanocomposites. Exposure of the blood and fibroblast cells to LLDPE/100Z and LLDPE/25T75Z/10% nanocomposite films for 48 and 72 h decreased their viability by less than 40%, compared with LLDPE, LLDPE/100T and LLDPE/25T75Z/5% nanocomposite films. It also presented possible cellular damage and cytotoxicity, which was supported by the findings from the significant release of extracellular lactate dehydrogenase profiles and cell survival assay Further observation using an electron microscope revealed that LLDPE films with heterogeneous 25T75Z/5% promoted cell adhesion. Moreover, no hemolysis was detected in all ratios of heterogeneous TiO₂/ZnO nanocomposite in LLDPE film as it was less than 0.2%, suggesting that these materials were hemocompatible. This study on LLDPE film with heterogeneous TiO₂/ZnO nanocomposites demonstrated favorable biocompatible properties that were significant for advanced biomedical polymer application in a hospital setting.

Biocompatibility and Cytotoxicity Study of Polydimethylsiloxane (PDMS) and Palm Oil Fuel Ash (POFA) Sustainable Super-Hydrophobic Coating for Biomedical Applications

A sustainable super-hydrophobic coating composed of silica from palm oil fuel ash (POFA) and polydimethylsiloxane (PDMS) was synthesised using isopropanol as a solvent and coated on a glass substrate. FESEM and AFM analyses were conducted to study the surface morphology of the coating. The super-hydrophobicity of the material was validated through goniometry, which showed a water contact angle of 151°. Cytotoxicity studies were conducted by assessing the cell viability and cell morphology of mouse fibroblast cell line (L929) and hamster lung fibroblast cell line (V79) via tetrazolium salt 3-(4–dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and microscopic methods, respectively. The clonogenic assay was performed on cell line V79 and the cell proliferation assay was performed on cell line L929. Both results validate that the toxicity of PDMS: SS coatings is dependent on the concentration of the super-hydrophobic coating. The results also indicate that concentrations above 12.5 mg/mL invariably leads to cell toxicity. These results conclusively support the possible utilisation of the synthesised super-hydrophobic coating for biomedical applications.

Determination toxic effects of Hystrix Brachyura Bezoar extracts using cancer cell lines and embryo zebrafish (Danio rerio) models and identification of active principles through GC-MS analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Porcupine bezoar (PB) is used as folk medicine for various medical conditions including cancer treatment in Malaysia. However, its toxicity profile has never been thoroughly ascertained to confirm its safe nature as an efficacious traditional medicine in the treatment of cancer as well as other ailments.

AIM OF THE STUDY

This study was aimed to reveal three different PBs' aqueous extracts(viz. PB-A, PB-B, PB-C) chemical constituent's profile using GC-MS analysis, anticancer property on A375, HeLa and MCF7 cancer cells, toxicity profile on zebrafish embryo morphology, EC₅₀, LC₅₀ and teratogenicity index.

MATERIALS AND METHODS

PBs' extracts characterization was performed through GC-MS analysis, in vitro anticancer effect was carried out on A375, HeLa and MCF7 cancer cell lines and finally and toxicity properties on three different PBs aqueous extracts (viz. PB-A, PB-B, PB-C) were determined using zebrafish embryo model.

RESULTS

The GC-MS analysis revealed 10 similar compounds in all PBs' extracts. Dilauryl thiodipropionate was found to be a major compound in all PBs' extracts followed by tetradecanoic acid. An in vitro anticancer study revealed PB extracts exerted median inhibition concentration (IC₅₀) <50 μg/mL, on cancer cells viz. A375, HeLa and MCF7 with no significant toxicity on normal cells viz. NHDF cells. In vivo toxicity of PBs extracts found affecting tail detachment, hatching, craniofacial, brain morphology, soft tissues, edema, spinal, somites, notochord and cardiovascular system (brachycardia, disruption of blood circulation) deformities. The LC₅₀ and EC₅₀ demonstrated PB extracts effect as dose and time dependent with median concentration <150.0 μg/mL. Additionally, teratogenicity index (TI) viz. >1.0 revealed teratogenic property for PB extracts.

CONCLUSIONS

The findings revealed that all three PBs aqueous extracts possessed anticancer activity and exhibited significant toxicological effects on zebrafish embryos with high teratogenicity index. Hence, its use as an anticancer agent requires further investigation and medical attentions to determine its safe dose.

The phytochemical analysis and pharmacological potentials of husk and straw as paddy waste products

Rice serves as a staple food for one-half of the global population. However, rice production, particularly the rice milling process, results in a substantial amount of paddy waste products (e.g. bran, husk and straw) annually. Because the potentials of bran have been extensively explored in prior studies, the present review focuses exclusively on the phytochemical analysis and pharmacological potentials of husk and straw. This comprehensive review establishes a solid foundation for promoting husk and straw as medicinal substances given their promising pharmacological potentials as bioactive compound sources with therapeutic functions. © 2020 Society of Chemical Industry.

Bactericidal Capacity of a Heterogeneous TiO2/ZnO Nanocomposite against Multidrug-Resistant and Non-Multidrug-Resistant Bacterial Strains Associated with Nosocomial Infections

The surge of medical devices associated with nosocomial infection (NI) cases, especially by multidrug-resistant (MDR) bacterial strains, is one of the pressing issues of present health care systems. Metal oxide nanoparticles (MNPs) have become promising antibacterial agents against a wide range of bacterial strains. This work study is on the bactericidal capacity of heterogeneous TiO₂/ZnO nanocomposites with different weight percentages and concentrations against common MDR and non-MDR bacterial strains. The profiles on disk diffusion, minimum inhibitory concentration, minimum bactericidal concentration, tolerance determination, time-kill, and biofilm inhibition assay were determined after 24 h of direct contact with the nanocomposite samples. Findings from this work revealed that the heterogeneous TiO₂/ZnO nanocomposite with a 25T75Z weight ratio showed an optimal tolerance ratio against Gram-positive and -negative bacteria, indicating their bactericidal capacity. Further observation suggests that higher molar ratio of Zn²⁺ may possibly involve generation of active ion species that enhance bactericidal effect against Gram-positive bacterial strains, especially for the MDR strains. Nano-based technology using MNPs may provide a promising solution for the prevention and control of NIs. Further work on biocompatibility and cytotoxicity profiles of this nanocomposite are needed.

VIS-NIR spectral signature and quantitative analysis of HeLa and DU145 cell line

Cancer is increasing in incidence and the leading cause of death worldwide. Controlling and reducing cancer requires early detection and technique to accurately detect and quantify predictive biomarkers. Optical spectroscopy has shown promising non-destructive ability to display distinctive spectral characteristics between cancerous and normal tissues from different part of human organ. Nonetheless, not many information is available on spectroscopic properties of cancer cell lines. In this research, the visible-near infrared (VIS-NIR) absorbance spectroscopy measurement of cultured cervical cancer (HeLa) and prostate cancer cells (DU145) lines has been performed to develop spectral signature of cancer cells and to generate algorithm to quantify cancer cells. Spectroscopic measurement on mouse skin fibroblast (L929) was also taken for comparative purposes. In visible region, the raw cells' spectra do not produce any noticeable peak absorbance that provides information on color because the medium used for cells is colorless and transparent. NIR wavelength between 950 and 975 nm exhibit significant peak due to water absorbance by the medium. Development of spectral signature for the cells through the application of regression technique significantly enhances the diverse characteristics between L929, HeLa and DU145. The application of multiple linear regression allows high measurement accuracy of the cells with coefficient of determination above 0.94.

Potential colorimetric detection of cancer cells using Phenol Red

The objective of this research is to examine the relationship between the color changes of phenol red and the growth of cancer cells, i.e., HeLa and DU145 cells, over a specific period of time. Normal mouse skin fibroblasts (L929 cells) were used as a reference. In this research, the color changes of phenol red due to the acidification of the cell culture medium from the growth of the cells over a period of nine hours showed potential colorimetric characteristics of cancer cells. The color changes of phenol red were observed using visible absorbance spectroscopy. The transformation of the absorbance spectra into coefficients of determination against the examined range of wavelengths created a distinctive spectral signature that signifies phenol red discoloration in cancer and normal cell culture lines.

Surface morphological and mechanical properties of zinc oxide eugenol using different types of ZnO nanopowder

Zinc oxide eugenol (ZOE) cements are generally made up of 80%-90% ZnO powder while the remaining content consists of eugenol bonding resin. ZnO structure plays a major role in the morphology and mechanical properties of ZOE. In this study, we investigated the effects of different particle sizes/shapes of ZnO particles on the surface and mechanical properties of ZOE. Three samples were prepared namely ZnO-Ax, ZnO-B and ZnO-K. The crystallite sizes calculated from XRD were 37.76 nm (ZnO-Ax), 39.46 nm (ZnO-B) and 42.20 nm (ZnO-K) while the average particle sizes obtained by DLS were 21.11nm (ZnO-Ax), 56.73 nm (ZnO-B) and 2012 nm (ZnO-K). Results revealed that the compressive strengths of ZOE-Ax and ZOE-B were improved by 87.92% and 57.16%, respectively, relative to that of commercial ZOE-K. Vickers hardness test demonstrated that the hardness of ZOE-Ax and ZOE-B also increased by 74.9% and 31.1%, respectively. The ZnO-Ax nanostructure possessed a small average particle size (21.11 nm), a homogeneous size distribution (DLS) and an oxygen-rich surface (from EDS and elemental mapping). Meanwhile, ZnO-B exhibited a slightly larger average particle size of 56.73 nm compared with that of other samples. Sample ZnO-Ax demonstrated the highest compressive strength which was attributed to its large particle surface area (21.11 nm particle size) that provided a large contact area and greater interfacial (or interlock) bonding capability if compared to that of ZnO-K sample (2012 nm particle size).

Abstract 203: Pseudosemiglabrin inhibits tumor angiogenesis and tumor growth of human colon cancer in xenograft mouse models by downregulating endothelial functions, Notch and VEGF pathways

Many antineoplasic agents were identified from natural product. One such agent is (-)-pseudosemiglabrin extracted from aerial parts of Tephrosia apollinea, while significant progress has been made in understanding the antineoplasic and anti-inflammatory of prenylated flavone (-)-pseudosemiglabrin (SSG), little is known about its antiangiogenic and antitumor in vivo. Using rat aortic ring assay and zebrafish model, SSG dramatically suppressed angiogenesis in vitro, ex vivo and in vivo models, SSG profoundly inhibited the outgrowth of new vessels from explants rat aortic ring, moreover it impaired human endothelial cells (HUVEC) migration and formation of capillary-like structure in vitro in none toxic doses. In this study we hypothesize that SSG can hampered tumor angiogenesis and tumor growth of colorectal cancer in ectopically and orthotopically implanted in nude mice, oral administration of SSG (25- 100mg/kg) significantly inhibited colon tumors growth in nude mice. Histological and Immunohistochemistry analysis further revealed that the stained blood vessels and expression of CD31 in xenograft were remarkably decreased in tumors excised from animals treated with SSG. Mechanistically the compound inhibits tumor angiogenesis by downregulation of Notch downstream (NCID); also SSG was found to inhibit VEGF secretion from human cancer cells as well as endothelial cells. In conclusion, the results demonstrated an original role of (-)-pseudosemiglabrin in inhibiting tumor angiogenesis and tumor growth via inhibition Notch and VEGF pathways. This study also validates the central role of Notch in tumor angiogenesis and suggests that (-)-pseudosemiglabrin could be a potential therapeutic candidate for cancer and other angiogenesis related diseases.

Note: This abstract was not presented at the meeting.

Citation Format: Loiy E. Ahmed Hassan, Azman Seeni, Amin M. Abdul Majid. Pseudosemiglabrin inhibits tumor angiogenesis and tumor growth of human colon cancer in xenograft mouse models by downregulating endothelial functions, Notch and VEGF pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 203.

Lactobacillus Strains Alleviated Aging Symptoms and Aging-Induced Metabolic Disorders in Aged Rats

Aging is an inevitable and ubiquitous progress that affects all living organisms. A total of 18 strains of lactic acid bacteria (LAB) were evaluated on the activation of adenosine monophosphate-activated protein kinase (AMPK), an intracellular energy sensor mediating lifespan extension. The cell-free supernatant (CFS) of Lactobacillus fermentum DR9 (LF-DR9), Lactobacillus paracasei OFS 0291 (LP-0291), and Lactobacillus helveticus OFS 1515 (LH-1515) showed the highest activation of AMPK and was further evaluated. The phosphorylation of AMPK by these three LAB strains was more evident in U2OS and C2C12 cells, compared to the other cell lines and control (P < .05). Using premature senescent Sprague-Dawley rats induced by D-galactose (D-gal), the administration of LAB (10 log CFU/rat/day) for 12 weeks prevented the shortening of telomere length in D-gal-treated rats compared to the untreated control (P < .05). LF-DR9 lowered gene expression of p53, a known senescent biomarker, in gastrocnemius muscle and tibia compared to the control. The selected LAB strains also enhanced lipid, renal, and liver profile of rats, suggesting added potential of the strains in preventing aging-induced metabolic diseases. Strain LP-0291 and LH-1515 showed ability to adhere to mucin, no antibiotic resistance, tolerated and proliferated under gastric and intestinal simulated conditions, and inhibited the growth of pathogens Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis, comparable to commercial probiotic LF-DR9 and Lactobacillus sakei Probio 65. This study provided an insight into the potential of LAB for exhibiting antisenescence effects, with potentials as new medicinal foods for targeted antiaging therapies.

The differential roles of caspase family members in mediating PF4-induced breast cancer apoptosis

INTRODUCTION

This study focused on PF4 effects on caspase-3,-6, -7, -8 and -9 which regulate the apopotosis process in breast cancer.

MATERIALS AND METHODS

Breast tumours were induced in forty 21-day-old female Sprague Dawley rats (SDRs) using MNU until tumour size reached 14.5 mm (SD: 0.5 mm). The rats were then divided into two groups: Group 1 (control injected with 0.9% saline; n = 20), and Group 2 (platelet factor 4 (PF4); n = 20). PF4 was administered through focal intralesional injection at 20 μg/lesion dose. Following 5-day treatment, the SDRs were sacrificed. Subsequently, representative sections from the tumour were obtained for haematoxylin and eosin (H&E) staining. The expressions of caspase-3, -6, -7, -8 and -9 were evaluated using immunohistochemistry (IHC) staining.

RESULTS

The majority of breast tumour specimens were of aggressive types [n_control = 13 (65%); n_PF4 = 12 (60%)]. Invasive ductal carcinoma not otherwise specified (IDC-NOS) was the most commonly observed breast tumour histology for control and PF4 groups (n = 8 (40%) in respective groups). PF4-treated group exhibited significant differences in the caspase-3, -6 and -8 expression levels compared to the control group (all p < 0.001). There were no significant differences in caspase-7 (p = 0.347) and caspase-9 (p = 0.373) expression levels between both groups.

CONCLUSION

This study found that PF4 acts via the caspase-mediated extrinsic apoptosis pathway without the involvement of the intrinsic pathway.

Using invertebrate model organisms for neuroscience research and training: an opportunity for Africa

Africa is faced with an increasing underrepresentation of her research progress in many fields of science including neuroscience. This underrepresentation stems from the very low investments directed towards research by African governments as these are thought to be high-priced. Scientists and researchers within the continent are left to compete highly for the very limited research grants or choose to fund research from their personal purse. Therefore, presenting a need for all possible strategies to make science and research approaches more affordable in Africa. This paper presents one of such strategy, which advocates the use of invertebrate animal models for neuroscience research in place of the commonly used vertebrate models. Invertebrates are cheaper, more available and easy to handle options and their use is on the rise, even in the developed societies of the world. Here, we investigate the current state of invertebrate neuroscience research in Africa looking at countries and institutions conducting neuroscience research with invertebrates and their publication output. We discuss the factors which impede invertebrate neuroscience research in Africa like lack of research infrastructure and adequate expert scientists and conclude by suggesting solutions to these challenges.

Bacteriostatic Activity of LLDPE Nanocomposite Embedded with Sol⁻Gel Synthesized TiO₂/ZnO Coupled Oxides at Various Ratios

Metal oxide-polymer nanocomposite has been proven to have selective bactericidal effects against the main and common pathogens (Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli)) that can cause harmful infectious diseases. As such, this study looked into the prospect of using TiO₂/ZnO with linear low-density polyethylene (LLDPE) to inactivate S. aureus and E. coli. The physical, structural, chemical, mechanical, and antibacterial properties of the nanocomposite were investigated in detail in this paper. The production of reactive species, such as hydroxyl radicals (•OH), holes (h⁺), superoxide anion radicals (O₂•¯), and zinc ion (Zn2+), released from the nanocomposite were quantified to elucidate the underlying antibacterial mechanisms. LLDPE/25T75Z with TiO₂/ZnO (1:3) nanocomposite displayed the best performance that inactivated S. aureus and E. coli by 95% and 100%, respectively. The dominant reactive active species and the zinc ion release toward the superior antibacterial effect of nanocomposite are discussed. This work does not only offer depiction of the effective element required for antimicrobial biomedical appliances, but also the essential structural characteristics to enhance water uptake to expedite photocatalytic activity of LLDPE/metal oxide nanocomposite for long term application.

Advancing Neuroscience Research in Africa: Invertebrate Species to the Rescue

Neuroscience research and training in many African countries are difficult due to funding and infrastructure deficit. This has resulted in few neuroscientists within Africa. However, invertebrates such as Drosophila and Caenorhabditis elegans could provide the perfect answer to these difficulties. These organisms are cheap, easy to handle and offer a comparable advantage over vertebrates in neuroscience research modeling because they have a simple nervous system and exhibit well-defined behaviors. Studies using invertebrates have helped to understand neurosciences and the complexes associated with it. If Africa wants to catch up with the rest of the world in neuroscience research, it needs to employ this innovative cost-effective approach in its research. To improve invertebrate neuroscience within the Africa continent, the authors advocated the establishment of invertebrate research centers either at regional or national level across Africa. Finally, there is also a need to provide public funding to consolidate the gains that have been made by not-for-profit international organizations over the years.

ID3017 New strategy in development of cancer chemopreventive agent using Malaysia Plant

Cancer had become worldwide problem that efforts in prevention and treatment of cancer had rapidly grew in any research institute. Meanwhile, epidemiological studies have demonstrated a positive correlation between consumption of vegetables, fruits and beverages with reduced risk of cancer. It is estimated there are around 8,100 plant species in the Malaysia rain forests, with 10% of them reported to have some medicinal value. However, to date not much investigation has been done on chemopreventive activities on cancer. Therefore, we had studied the chemopreventive activity using various type of local plants such as Christia sp, Nephelium lappaceuem, Cocos nucifera and many more others which we going to present here. But, to combat with this miserable disease, we still need new strategies to overcome the problem and we also utilized the waste product from our tropical fruits and Paddy waste which might have beneficial effect towards cancer chemoprevention activities. We also going to present our strategy in developing mouthwash product to prevent oral cancer using bonsai plant, Streblus asper with demonstrable efficacy against defined molecular target on cancer cell line as well as in animal models. It is clearly shown that S. asper root extracts that have the anti-oxidant characteristic with analgesic properties via Inositol, not only kill oral-microbes but interestingly also inhibit the growth of osteosarcoma cells, tongue carcinoma cells and cervical cancer cells. The inhibition effect was through the induction of apoptosis signaling pathway. This mouthwash product also is non-toxic for the liver, kidney and skin fibroblast cells and no heavy metals were found. Currently, we now focused the use of the same product on cervical cancer and might develop it as a ladies hygiene product which act as chemopreventive agent. Futhermore S.asper also can suppressed the proliferative activity of the epithelium cells in Benign Prostate Hyperplasia animal model. Lets combat the cancer disease using new strategies.

Effects of rapamycin on cell apoptosis in MCF-7 human breast cancer cells

BACKGROUND

Rapamycin is an effective anti-angiogenic drug. However, the mode of its action remains unclear. Therefore, in this study, we aimed to elucidate the antitumor mechanism of rapamycin, hypothetically via apoptotic promotion, using MCF-7 breast cancer cells.

MATERIALS AND METHODS

MCF-7 cells were plated at a density of 15105 cells/well in 6-well plates. After 24h, cells were treated with a series of concentrations of rapamycin while only adding DMEM medium with PEG for the control regiment and grown at 37oC, 5% CO2 and 95% air for 72h. Trypan blue was used to determine the cell viability and proliferation. Untreated and rapamycin-treated MCF-7 cells were also examined for morphological changes with an inverted-phase contrast microscope. Alteration in cell morphology was ascertained, along with a stage in the cell cycle and proliferation. In addition, cytotoxicity testing was performed using normal mouse breast mammary pads.

RESULTS

Our results clearly showed that rapamycin exhibited inhibitory activity on MCF-7 cell lines. The IC50 value of rapamycin on the MCF-7 cells was determined as 0.4μg/ml (p<0.05). Direct observation by inverted microscopy demonstrated that the MCF-7 cells treated with rapamycin showed characteristic features of apoptosis including cell shrinkage, vascularization and autophagy. Cells underwent early apoptosis up to 24% after 72h. Analysis of the cell cycle showed an increase in the G0G1 phase cell population and a corresponding decrease in the S and G2M phase populations, from 81.5% to 91.3% and 17.3% to 7.9%, respectively.

CONCLUSIONS

This study demonstrated that rapamycin may potentially act as an anti-cancer agent via the inhibition of growth with some morphological changes of the MCF-7 cancer cells, arrest cell cycle progression at G0/G1 phase and induction of apoptosis in late stage of apoptosis. Further studies are needed to further characterize the mode of action of rapamycin as an anti-cancer agent.

Review on Zinc Oxide Nanoparticles: Antibacterial Activity and Toxicity Mechanism

Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide particularly by the implementation of nanotechnology to synthesize particles in the nanometer region. Many microorganisms exist in the range from hundreds of nanometers to tens of micrometers. ZnO-NPs exhibit attractive antibacterial properties due to increased specific surface area as the reduced particle size leading to enhanced particle surface reactivity. ZnO is a bio-safe material that possesses photo-oxidizing and photocatalysis impacts on chemical and biological species. This review covered ZnO-NPs antibacterial activity including testing methods, impact of UV illumination, ZnO particle properties (size, concentration, morphology, and defects), particle surface modification, and minimum inhibitory concentration. Particular emphasize was given to bactericidal and bacteriostatic mechanisms with focus on generation of reactive oxygen species (ROS) including hydrogen peroxide (H2O2), OH- (hydroxyl radicals), and O2 -2 (peroxide). ROS has been a major factor for several mechanisms including cell wall damage due to ZnO-localized interaction, enhanced membrane permeability, internalization of NPs due to loss of proton motive force and uptake of toxic dissolved zinc ions. These have led to mitochondria weakness, intracellular outflow, and release in gene expression of oxidative stress which caused eventual cell growth inhibition and cell death. In some cases, enhanced antibacterial activity can be attributed to surface defects on ZnO abrasive surface texture. One functional application of the ZnO antibacterial bioactivity was discussed in food packaging industry where ZnO-NPs are used as an antibacterial agent toward foodborne diseases. Proper incorporation of ZnO-NPs into packaging materials can cause interaction with foodborne pathogens, thereby releasing NPs onto food surface where they come in contact with bad bacteria and cause the bacterial death and/or inhibition.

Review on Zinc Oxide Nanoparticles: Antibacterial Activity and Toxicity Mechanism

Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide particularly by the implementation of nanotechnology to synthesize particles in the nanometer region. Many microorganisms exist in the range from hundreds of nanometers to tens of micrometers. ZnO-NPs exhibit attractive antibacterial properties due to increased specific surface area as the reduced particle size leading to enhanced particle surface reactivity. ZnO is a bio-safe material that possesses photo-oxidizing and photocatalysis impacts on chemical and biological species. This review covered ZnO-NPs antibacterial activity including testing methods, impact of UV illumination, ZnO particle properties (size, concentration, morphology, and defects), particle surface modification, and minimum inhibitory concentration. Particular emphasize was given to bactericidal and bacteriostatic mechanisms with focus on generation of reactive oxygen species (ROS) including hydrogen peroxide (H₂O₂), OH^- (hydroxyl radicals), and O₂ ^-2 (peroxide). ROS has been a major factor for several mechanisms including cell wall damage due to ZnO-localized interaction, enhanced membrane permeability, internalization of NPs due to loss of proton motive force and uptake of toxic dissolved zinc ions. These have led to mitochondria weakness, intracellular outflow, and release in gene expression of oxidative stress which caused eventual cell growth inhibition and cell death. In some cases, enhanced antibacterial activity can be attributed to surface defects on ZnO abrasive surface texture. One functional application of the ZnO antibacterial bioactivity was discussed in food packaging industry where ZnO-NPs are used as an antibacterial agent toward foodborne diseases. Proper incorporation of ZnO-NPs into packaging materials can cause interaction with foodborne pathogens, thereby releasing NPs onto food surface where they come in contact with bad bacteria and cause the bacterial death and/or inhibition.

Therapeutic targeting of angiotensin II receptor type 1 to regulate androgen receptor in prostate cancer

BACKGROUND

With the limited strategies for curative treatment of castration-resistant prostate cancer (CRPC), public interest has focused on the potential prevention of prostate cancer. Recent studies have demonstrated that an angiotensin II receptor blocker (ARB) has the potential to decrease serum prostate-specific antigen (PSA) level and improve performance status in CRPC patients. These facts prompted us to investigate the direct effects of ARBs on prostate cancer growth and progression.

METHODS

Transgenic rat for adenocarcinoma of prostate (TRAP) model established in our laboratory was used. TRAP rats of 3 weeks of age received ARB (telmisartan or candesartan) at the concentration of 2 or 10 mg/kg/day in drinking water for 12 weeks. In vitro analyses for cell growth, ubiquitylation or reporter gene assay were performed using LNCaP cells.

RESULTS

We found that both telmisartan and candesartan attenuated prostate carcinogenesis in TRAP rats by augmentation of apoptosis resulting from activation of caspases, inactivation of p38 MAPK and down-regulation of the androgen receptor (AR). Further, microarray analysis demonstrated up-regulation of estrogen receptor β (ERβ) by ARB treatment. In both parental and androgen-independent LNCaP cells, ARB inhibited both cell growth and AR-mediated transcriptional activity. ARB also exerted a mild additional effect on AR-mediated transcriptional activation by the ERβ up-regulation. An intervention study revealed that PSA progression was prolonged in prostate cancer patients given an ARB compared with placebo control.

CONCLUSION

These data provide a new concept that ARBs are promising potential chemopreventive and chemotherapeutic agents for prostate cancer.

Hypertension is positively associated with prostate cancer development in the TRAP transgenic rat model

Epidemiological data on the relationship between hypertension and prostate cancer development are conflicting. To cast light on this question, we performed animal experiments using hybrid rats generated by crossing the spontaneously hypertensive rat (SHR) or its normotensive control Wistar Kyoto (WKY) rat with a transgenic rat for adenocarcinoma of prostate (TRAP) that features development of adenocarcinoma at high incidence by 15 weeks of age. The number of adenocarcinomatous foci in the lateral prostate of hypertensive (TRAP × SHR)F1 rats was demonstrated to be significantly increased compared with those of normotensive (TRAP × WKY)F1 rats. In the ventral prostate, increase of carcinoma foci was also observed but did not reach significance. The number of cancer foci showing microinvasion in (TRAP × SHR)F1 rats was higher than that of (TRAP × WKY)F1 rats, but again without significance, while treatment with prazosin, an anti-hypertensive agent, tended to decrease microinvasive carcinoma foci in both the ventral and lateral prostate. In conclusion, the present study provided additional evidence that high blood pressure is associated with prostate cancer risk.

A synthetic hydrazone derivative acts as an apoptotic inducer with chemopreventive activity on a tongue cancer cell line

One of the main aims of cancer chemopreventive studies is to identify ideal apoptotic inducers, especially examples which can induce early apoptotic activity. The present investigation focused on chemopreventive effects of a hydrazone derivative using an in vitro model with tongue cancer cells. Alteration in cell morphology was ascertained, along with stage in the cell cycle and proliferation, while living-dead status of the cells was confirmed under a confocal microscope. In addition, cytotoxicity test was performed using normal mouse skin fibroblast cells. The results showed that the compound inhibited the growth of tongue cancer cells with an inhibitory concentration (IC₅₀) of 0.01 mg/ml in a dose and time-dependent manner, with a two-fold increase in early apoptotic activity and G0G1 phase cell cycle arrest compared to untreated cells. Exposure to the compound also resulted in alterations of cell morphology including vacuolization and cellular shrinkage. Confocal microscope analysis using calcein and ethidium staining confirmed that the compound caused cell death, whereas no cytotoxic effects on normal mouse skin fibroblast cells were observed. In conclusion, the findings in this study suggested that the hydrazone derivative acts as an apoptotic inducer with anti-proliferative chemopreventive activity in tongue cancer cells.

Abstract B73: Chemopreventive effect of Streblus asper, a bonsai plant, on osteosarcoma cells: A preliminary study

Epidemiological studies have demonstrated a positive correlation between consumption of vegetables, fruits and beverages with reduced risk of cancer. It is estimated there are around 8,100 plant species in the Malaysian rain forests, with 10% of them reported to have some medicinal value. However, to date in Malaysia, not much investigation has been done on chemopreventive activities on cancer although Malaysian plants are an exclusive source of effective chemopreventive agents and therefore, this background leads to the premise that our local plants such as Streblus asper could have greater potential for the chemoprevention activities. Streblus asper is well known as an expensive bonsai plant which is indigenous to tropical countries such as Malaysia, Thailand, Sri Lanka and India. It is used traditionally in leprosy, piles, diarrhea, dysentery, elephantiasis and cancer. It finds place in Ayurvedic Pharmacopoeia of India and also been described in some monographs, but none have reported its activity as chemopreventive agents and the underlying mechanisms remain unclear. In the present study, we try to identify its biological properties and the cytotoxicity effect on normal liver and kidney cells. Using the osteosarcoma cells as our in vitro model, the IC50 of Streblus asper root extract was determined and observed its effect on the osteosarcoma cells morphology that changes within time, the anti-proliferative pattern and live-death analysis under confocal microscope analysis. The results showed that the root extracts did not contained any heavy metals compound such as mercury and cadmium and with less arsenic (0.02 ppm) and plumbum (0.07 ppm) and showing non-cytotoxic effect on vero cells (normal kidney cells) and WRL-68 cells (normal liver cells). Our HPLC profiling analysis also revealed antioxidants compounds exist in the Streblus asper root extracts such as caffeic acid which has been shown to act as a carcinogenic inhibitor. Although the low-level of anti-oxidants been found from the extracts but it still can inhibit the growth of the osteosarcoma cells which also exert apoptosis features like cell shrinkage (atrophy) and vocalization in time and dose-dependent manner. The plant extracts IC50 doses was at 0.05% of root extracts and it also demonstrated the anti-proliferative effect by suppressed the cells growth as early as 12 hours of treatment and marked cell death till day 6. On live-death analysis under confocal microscope using Calcein and Ethidium staining confirmed that Streblus asper root extract exert cell death to osteosarsoma cells. This study is just a preliminary study as to identify its pharmacological properties on carcinogenesis and further investigation is still on-going to develop it as the chemopreventive agent especially to determine the signaling pathway involved.

Citation Information: Cancer Prev Res 2010;3(1 Suppl):B73.

Suppression of prostate cancer in a transgenic rat model via gamma-tocopherol activation of caspase signaling

BACKGROUND

Epidemiological data indicate that intake of one form of vitamin E, gamma-tocopherol, may reduce prostate cancer risk, and several in vitro studies have demonstrated that gamma-tocopherol can inhibit prostate cancer cell growth. The purpose of the present study was to confirm effects of gamma-tocopherol on prostate cancer in the transgenic rat for adenocarcinoma of prostate (TRAP) model established in our laboratory.

METHODS

In Experiment 1, heterozygous male TRAP rats 5 weeks of age received alpha-tocopherol at the concentration of 50 mg/kg in the diet, or gamma-tocopherol at 50 or 100 mg/kg for 10 weeks. In Experiment 2, TRAP rats of 3 weeks of age were given gamma-tocopherol at 50, 100, or 200 mg/kg diet for 7 weeks.

RESULTS

gamma-Tocopherol did not affect body weight gain, organ weights or serum levels of either testosterone or estradiol. However, quantitative evaluation of prostatic lesions demonstrated significantly suppression of sequential progression from PIN to adenocarcinoma in a dose-dependent manner, along with clear activation of caspases 3 and 7 in the ventral lobe in both experiments.

CONCLUSIONS

The present study clearly demonstrated that gamma-tocopherol suppresses prostate tumor progression in an in vivo TRAP model, and could be a candidate chemopreventive agent for human prostate cancer.

Prevalence of human papillomavirus in abnormal cervical smears in Malaysian patients

Cervical cancer is the second most common female malignancy in Malaysia. Despite advances in treatment, the overall survival for this disease has not changed in the last decade. Infection by certain types of HPV is recognized as a causal and necessary factor for its development. This study was carried out to determine the prevalence of HPV infection in abnormal cervical smears in Malaysian patients using archival cervical smears retrieved from the Cytopathology Unit, Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between the years 1992-1995. DNA was extracted from 38 abnormal smears comprising 25 intraepithelial lesions and 13 cervical carcinomas and 10 normal smears. Amplification of HPV genes was carried out using the polymerase chain reaction (PCR) technique. HPV genotypes were determined using direct sequencing and the results were compared to the database from Genebank. DNA was successfully extracted from all 48 cervical smears. High-risk HPV (HR-HPV) genotypes were detected in 95% of the abnormal smears. Eight high-risk oncogenic types were identified: 16, 18, 31, 51, 52, 56, 58 and 66. All (100%) cervical cancer smears showed presence of HR-HPV compared to 92% of the cervical intraepithelial lesions. Among the eight HR-HPV genotypes identified, HPV 16 and 52 were the commonest (23.7% each) HPV genotypes encountered and among the CIN lesions, HPV 16 (28%) was the most frequent. We conclude that HPV 16 is the most prevalent HPV genotype present in abnormal cervical smears in Malaysian patients, and that the use of archival material to assess the presence of HPV is potentially worthwhile, and can be utilized for longitudinal studies of HPV presence and persistence.

Suppression of prostate cancer growth by resveratrol in the transgenic rat for adenocarcinoma of prostate (TRAP) model

Research into actions of resveratrol, abundantly present in red grape skin, has been greatly stimulated by its reported beneficial health influence. Since it was recently proposed as a potential prostate cancer chemopreventive agent, we here performed an in vivo experiment to explore its effect in the Transgenic Rat for Adenocarcinoma of Prostate (TRAP) model, featuring the rat probasin promoter/SV 40 T antigen. Resveratrol suppressed prostate cancer growth and induction of apoptosis through androgen receptor (AR) down-regulation, without any sign of toxicity. Resveratrol not only downregulated androgen receptor (AR) expression but also suppressed the androgen responsive glandular kallikrein 11 (Gk11), known to be an ortholog of the human prostate specific antigen (PSA), at the mRNA level. The data provide a mechanistic basis for resveratrol chemopreventive efficacy against prostate cancer.

Protective effects of citrus nobiletin and auraptene in transgenic rats developing adenocarcinoma of the prostate (TRAP) and human prostate carcinoma cells

Dietary phytochemicals, including nobiletin and auraptene, have been shown to exert inhibiting effects in several chemically induced carcinogenesis models. We here investigated the influence of nobiletin and auraptene on prostate carcinogenesis using transgenic rats developing adenocarcinoma of the prostate (TRAP) bearing the SV40 T antigen transgene under control of the probasin promoter and human prostate cancer cells. Starting at 5 weeks of age, male TRAP rats received powder diet containing 500 p.p.m. nobiletin or auraptene, or the basal diet for 15 weeks and then were sacrificed for analysis of serum testosterone levels and histological changes. The body and relative prostate weights and serum testosterone levels did not differ among the groups. Since all animals developed prostate carcinomas, these were semiquantitatively measured and expressed as relative areas of prostate epithelial cells. Nobiletin caused significant reduction in the ventral (P<0.01), lateral (P<0.001) and dorsal (P<0.05) prostate lobes, while decreasing high grade lesions (P<0.05) in the ventral and lateral lobes. Feeding of auraptene also effectively reduced the epithelial component (P<0.05) and high grade lesions (P<0.05), in the lateral prostate. A further experiment demonstrated that growth of androgen sensitive LNCaP and androgen insensitive DU145 and PC3 human prostate cancer cells, was suppressed by both nobiletin and to a lesser extent auraptene in a dose-dependent manner, with significant increase in apoptosis. In conclusion, these compounds, particularly nobiletin, may be valuable for prostate cancer prevention.