Growth Of HCT Research Articles

Chemical profiling of fungal metabolites via the OSMAC approach: Novel identification of Brianthein W from an endophytic fungus, Hypomontagnella monticulosa Zg15SU

In the previous report, we reported that Hypomontagnella monticulosa originating from the rhizome of Zingiber griffithii was known to produce a marine-derived natural product. An OSMAC-based approach was designed by modifying the nutritional composition of the growth medium to investigate any possible new metabolites produced by the strain. The culture filtrate and biomass were conditioned through the use of three basal media, namely, Czapek-dox, potato dextrose, and Wickersham broth medium. GC-MS and multivariate analysis was performed to distinguish the chemicals and determine their composition in the tested extracts. Antimicrobial activity was tested against selected human pathogenic microbes using the disk-diffusion method. The MeOH extract of both culture filtrate and biomass from different fermentation media revealed that the majority of identified compounds (n=40) were found in Wickerham medium (n=23), which is later termed as MeOH-Wi. The chemical composition of MeOH-Wi was fatty acids (21.74%), followed by terpenoids (17.38%), cyclosiloxane (13.04%), aldehydes (13.04%), alkenes (8.7%), hydrocarbons (8.7%), esters (8.7%), alkaloids (4.35%), and an unclassified compound, the 9,9-Dimethyl-3,7-diazabicyclo[3.3.1]nonane. The numerous chemical compounds in MeOH-Wi corresponded with its antimicrobial activities against Micrococcus luteus NBRC 13867 (±11 mm), Candida maltosa NBRC 1977 (±9 mm), and Escherichia coli JM 109 (±5 mm) which were higher than the other tested extracts. Further purification using HPLC RP-C18 using NP-SiO2/n-Hex–EtOAc (10:2) to yield compound (1). Compound (1) was determined as an analog of briarian W—a diterpene mostly found in marine sponge, Briareum spp.—as a pure compound in the MeOH extract of H. monticulosa based on the 1D and 2D NMR analysis. The anticancer activity (IC50) of compound (1) was 0.077, 0.080, and 0.102 µg/mL against the growth of HCT-116, NBT-T2, and Panc-1, respectively. As far as we are aware, this is the first report on finding a briarian diterpene that originates from an endophytic fungus, especially by H. monticulosa.

Metformin Induces a Caspase 3-Unrelated Apoptosis in Human Colorectal Cancer Cell Lines HCT116 and SW620.

To study the effects of metformin on the proliferation and growth of human colorectal cancer cell lines HCT116 and SW620. The antiproliferative effect of metformin was assayed using an MTS reagent and its ability to inhibit colony formation was demonstrated using a clonogenic assay. Flow cytometry using YO-PRO-1/PI was performed to examine the effects of metformin on apoptosis and cell death of HCT116 and SW620. Caspase 3 activities were measured in caspase-3 activity tests using a caspase-3 activity kit. Furthermore, Western blots were performed with anti-PARP1, anti-caspase 3, and anti-cleaved caspase 3 to confirm whether caspase activation was present or not. Both MTS proliferation assays and clonogenic assays showed that metformin inhibited the proliferation and growth of HCT116 and SW620 cells in a concentration-dependent manner. Flow cytometric analysis identified early apoptosis and metformin-induced cell death in both cell lines. However, caspase 3 activity could not be detected. Cleavage of both PARP1 and pro-caspase 3 was not observed in the Western blot, confirming the absence of caspase 3 activations. This present study suggests a caspase 3-unrelated apoptosis mechanism of metformin-induced cell death in human colorectal cancer cell lines HCT116 and SW620.

DNA Damage and Apoptosis as In-Vitro Effect Biomarkers of Titanium Dioxide Nanoparticles (TiO2-NPs) and the Food Additive E171 Toxicity in Colon Cancer Cells: HCT-116 and Caco-2.

This study investigated the DNA damage and apoptosis in colon cancer cells HCT-116 and Caco-2 induced by engineered titanium dioxide nanoparticles (TiO2-NPs) (60 nm) and titanium dioxide food additive E171. MTT assays showed that both chemical forms significantly reduced cancer cell viability in a dose-dependent manner. In particular the food additive E171 induced a pronounced inhibitory effect on the growth of HCT-116 and Caco-2 cell lines (E171 IC50: 3.45 mg/L for HTC-116 and 1.88 mg/L Caco-2; TiO2-NPs 60 nm IC50: 41.1 mg/L for HTC-116 and 14.3 mg/L for Caco-2). A low level of genotoxicity was observed in Caco-2 cells, especially when treated with TiO2 60 nm. Western blot analysis showed that HCT116 and Caco-2 treated cells did not overexpress apoptotic markers such as cleaved Caspase 3 and cleaved Parp. Moreover, further analysis by quantitative real-time PCR (qRT-PCR) showed that TiO2-NPs and E171 did not promote the expression of Bax or downregulation of Bcl-2, nor did they increase the Bax/Bcl-2 ratio. The assay data provide clear evidence that TiO2 can cause DNA damage but does not induce apoptosis or decrease long-term cell proliferation. In addition, the results show that E171 has a slightly higher level of cytotoxicity and genotoxicity. This suggests that exposure to E171 may be hazardous to health and that further research on biological effects is needed to promote safer practices in the use of this compound.

Cucurbitacin B controls M2 macrophage polarization to suppresses metastasis via targeting JAK-2/STAT3 signalling pathway in colorectal cancer

Ethnopharmacological relevanceCucurbitacin B (CuB), extracted from muskmelon pedicel, is a widely available triterpenoid molecule that exerts influence on various biological activities. Modern pharmacological studies have found that cucurbitacin B has many kinds of pharmacological anti-tumor and anti-metastasis functions. Aim of the studyTo explore the mechanism of anti-tumor and anti-metastasis effect of cucurbitacin B. Materials and methodsThe effect of cucurbitacin B on the growth of HCT116 and CT-26 was detected by CCK8; apoptosis was determined by flow cytometry and colony formation; the expression of apoptosis-related protein Bax, Bcl-2 and Cleaved-caspase-3 were examined by western Blot. To explore the underlying mechanism of cucurbitacin B against tumor, the Western blot, Immunofluorescence staining, Microscale Thermophoresis assays were used. Multiple molecular biology experiments were applied to validate the effect of polarization of cucurbitacin B-induced macrophages. The supernatant of Cucurbitacin B-induced macrophages and colon cells were co-cultured in vitro, and then transwell and wound healing assay were employed to the related phenotypes. C57BL/6 and BALB/c murine colon cancer model were also used to study the drug effects in vivo. ResultsCucurbitacin B distinctly induced the apoptosis of CRC cells. It was observed that cucurbitacin B not only inhibited the phosphorylation of JAK2 and STAT3, but also the translocation from the cytosol to the nucleus. Meanwhile, we observed that cucurbitacin B is bound to STAT3. Further experimentation demonstrated that cucurbitacin B reduced the polarization of M2 macrophage by down-regulating JAK2/STAT3 signaling pathway. Cucurbitacin B-induced M2-like macrophages were found to diminish the migration of CRC cells. In vitro study suggested that cucurbitacin inhibited the CRC cells proliferation via JAK2/STAT3 and suppressed the cell migration by suppressing M2-like macrophages polarization. Consistent with in vitro results, the cucurbitacin B therapy significantly inhibited tumor growth and metastasis in mice. Moreover, in vivo the treatment with cucurbitacin B enhanced anti-tumor immunity by regulating M2-like macrophages and promoted the expression of CD4 and CD8 in tumor microenvironment. ConclusionOur results proved that cucurbitacin B might be a potential candidate agent for adjuvant therapy in the process of CRC growth and metastasis.

Spectrochemical analysis using LIBS and ICP-OES techniques of herbal medicine (Tinnevelly Senna leaves) and its anti-cancerous/antibacterial applications

Tinnevelly senna leaves are being applied to cure many diseases especially in developing countries and sub-Saharan region due to many bioactive compounds such as sennosides, phenols, and flavonoids. The conventional methods to isolate and analyze plant extracts biomolecules are not very effective as well cost effective as they require hazardous chemical solvents and reagents, which are time-consuming processes. The major objective of the present study is to investigate the feasibility of the Laser induced breakdown spectroscopy (LIBS) technique for rapid, eco-friendly, and multi-elemental analysis of Senna leaves extracts and study their antibacterial and anticancer potentials. The elegant LIBS technique was applied as a qualitative and quantitative method for Senna leaves sample’s elemental analysis and their biological activities were measured by evaluating anti-cancer and anti-bacterial analysis. The quantitative analysis of Senna leaves extracts was done using the calibration-free laser-induced breakdown spectroscopy (CF-LIBS) algorithm showing their appreciable content of several nutrient elements, and the obtained results were in close conformity with these achieved by using the standard analytical ICP OES technique. We studied the bactericidal efficacy of the Senna leaves extract against Staphylococcus aureus ( S. aureus ) by AWD assays and morphogenesis by scanning electron microscopy (SEM) and the anticancer activity was also investigated where different concentrations of Senna leaves extract were tested on cancer cells (HCT-116 and HeLa) and normal cells (HEK-293) using the cell metabolic activity MTT assay and Propidium iodide (PI) staining. We have also calculated the inhibitory concentration (IC50) value for the various extracts concentrations (25 µg/ml, 50 µg/ml, 100 µg/ml, 150 µg/ml, 200 µg/ml, and 225 µg/ml). We have found that IC 50 value for HCT-116 cells were 13.5 µg/ml, 17.5 µg/ml, 21.5 µg/ml, 22.5 µg/ml, 26 µg/ml and 33.5 µg/ml and for HeLa cells 15.25 µg/ml, 21.25 µg/ml, 23.5 µg/ml, 262.5 µg/ml, 36.25 µg/ml, and 39.50 µg/ml. The bactericidal efficacy of the Senna leaves extract showed significant inhibition against Gram-positive bacterium. Both MTT and PI analysis showed that Senna leaves extract induced profound inhibition on HCT-116 growth and proliferation. Additionally, Senna leaves extract did not exert an inhibitory influence on normal (HEK-293), which is non-cancerous cells. We suggest that the extract specifically targets the cancerous cells, which could be highly beneficial for the development of future safe anticancer and antibacterial drugs using these extracts.

Fabrication of polylactic acid/paclitaxel nano fibers by electrospinning for cancer therapeutics

Polylactic acid (PLA) is a thermoplastic and biodegradable polyester, largely derived from renewable resources such as corn starch, cassava starch and sugarcane. However, PLA is only soluble in a narrow range of solvents such as tetrahydrofuran, dioxane, chlorinated solvents and heated benzene. The limited choices of solvent for PLA dissolution have imposed significant challenges in the development of specifically engineered PLA nanofibers with electrospinning techniques. Generally, the electrospun polymeric materials have been rendered with unique properties such as high porosity and complex geometry while maintaining its biodegradability and biocompatibility for emerging biomedical applications. In this study, a new anticancer drug delivery system composed of PLA nanofibers with encapsulated paclitaxel was developed by the electrospinning of the respective nanofibers on top of a spin-coated thin film with the same chemical compositions. Our unique approach is meant for promoting strong bonding between PLA-based nanofibers and their respective films in order to improve the prolonged release properties and composite film stability within a fluctuative physiochemical environment during cell culture. PLA/paclitaxel nanofiber supported on respective polymeric films were probed by scanning electronic microscope, Fourier transform infrared spectrometer and water contact measurement for determining their surface morphologies, fibers’ diameters, molecular vibrational modes, and wettability, respectively. Moreover, PLA/paclitaxel nanofibers supported on respective spin-coated films at different loadings of paclitaxel were evaluated for their abilities in killing human colorectal carcinoma cells (HCT-116). More importantly, MTT assays showed that regardless of the concentrations of paclitaxel, the growth of HCT-116 was effectively inhibited by the prolonged release of paclitaxel from PLA/paclitaxel nanofibers. An effective prolonged delivery system of paclitaxel based on PLA nanofiber-based film has demonstrated exciting potentials for emerging applications as implantable drug delivery patch in post-surgical cancer eradication.

In vitro Screening of Berberis lycium Root Extract on HCT-116 and MCF-7 Cell Lines

The objective of the current study was to evaluate the antioxidant, lethality and anticancer potential of root extracts of Berberis lycium. Equal weight of powdered roots was used to prepare water, methanol, ethyl acetate and n-hexane extracts. Methanol extract of Berberis lycium showed promising 2,2-diphenyl-1-picrylhydrazyl free radical scavenging potential with an IC50 of 144.31 µg/ml. In the brine shrimp lethality assay, the ethyl acetate extract produced 53.33 % mortality at 1000 µg/ml and its LD50 was 907.7 µg/ml. In the sulforhodamine B colorimetric cytotoxicity screening assay, methanol extracts of Berberis lycium caused 45 % inhibition in growth of HCT116, without producing much effect against MCF7 cell line. In addition, the potential mediators that could be involved in mediating these activities include AKT1, TP53, JUN, and TLR4. In conclusion, methanol extract of Berberis lycium exhibited excellent antioxidant, brine shrimp lethality, and cytotoxic activities, indicating the potential of this plant against colorectal and breast cancer.

Synthesis of Piperidine Conjugated Dihydroquinazolin-4(1H)-ones and their Antiproliferative Activity, Molecular Docking Studies and DFT Calculations

Background: Xanthatin, fluoropyrimidine and thienopyrimidine, pyrazolopyrimidine, pyrimidine carboxamides, and SKLB1002 are reported as VEGFR2 tyrosine kinase inhibitors. Recently, many studies related to different heterocycles conjugated with dihydroquinazolinones are known to have very good biological activities. In this study, we are intended to explore the cytotoxic studies of piperidine conjugated dihydroquinazolinones against colorectal/colon cancer cell lines and along with molecular docking studies and DFT calculations. Methods: The colorectal/colon cell lines HCT116 and A549 cell lines were treated with these compounds and cytotoxic activities were evaluated by MTT dye uptake method. We performed molecular modelling for compound 3d using the Auto Dock software. The binding of compound 3d with target proteins was studied with the collection of experimentally determined PDB database. Optimized geometry by DFT calculations was performed with B3LYP/6-31G (d) basis set. Results: Piperidine-conjugated dihydroquinazolinone analogues displayed anticancer activity. Particularly, the compound 3d with electron-withdrawing substituents on a phenyl ring showed significant cytotoxicity against HCT116 and A549 cell lines. Molecular docking studies proved that the compound 3d has good fitting by forming hydrogen bonds with amino acid residues at the active sites of VEGFR2. The HOMO, LUMO, their energies and UV visible spectrum were predicted using DFT calculations. Conclusion: Four piperidine-conjugated dihydroquinazolinones were synthesized and evaluated against colorectal and colon cancer cell lines. Compound 3d significantly inhibited the growth of HCT116 and A549. Molecular docking studies displayed good fitting of compound 3d by forming different H-bonds with the amino acid at the active sites of the VEGFR2 target. Using a theoretical approach, we optimized HOMO and LUMO plots for the compound 3d.

Abstract C013: HI-B9 suppresses colorectal cancer by inhibiting Wnt/β-catenin pathway

Abstract Deregulated Wnt/β-catenin pathway plays an important role in colorectal cancer. β-Catenin interacts with transcription factor 7-like 2 (TCF7L2 or TCF4) to express oncogenes including c-myc, axin2 and cyclin D1. Here we describe a small molecule, referred to as HI-B9, which inhibits the growth of colorectal cancer cell lines. HI-B9 suppressed tryptophan fluorescence of β-catenin that contains TCF4-binding residues. In silico docking of HI-B9 on β-catenin showed a binding mode that blocks Lys 312 residue which is critical for the interaction between β-catenin and its interactors. A binding assay showed that the binding affinity of HI-B9 against β-catenin G307A/K312E mutant was significantly reduced compared to that against wildtype. HI-B9 inhibited β-catenin/TCF4 luciferase activity in a dose-dependent manner. Anchorage-independent growth of HCT116 and HT29 colorectal cancer cells were suppressed by the small molecule. mRNA expression levels of Wnt target genes were reduced by HI-B9 treatment. HI-B9 did not affect the translocation of β-catenin toward the nucleus. The therapeutic effects of HI-B9 was due to the disruption of β-catenin/TCF4 complex formation ex vivo. Our findings demonstrate the therapeutic potential of HI-B9 against colorectal cancer with aberrant Wnt/β-Catenin signaling pathway. Citation Format: Seung Ho Shin, Kanamata Reddy, Zigang Dong. HI-B9 suppresses colorectal cancer by inhibiting Wnt/β-catenin pathway [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C013. doi:10.1158/1535-7163.TARG-19-C013

Innovative dual system for selective eradication of cancer cells using exosomes carrying natural bacterial toxin-antitoxin (TA).

e14635 Background: Inactivation of P53 and activation of ras are frequent genetic alterations in cancer. We have shown in vitro and in vivo, that the TA system can selectively and effectively eradicate RAS-mutated cancer cells. Aim: Selective killing of cancer cells while sparing the normal cells based on tumor genetic signature. Methods: A “first generation” ΔE1/ΔE3 human type-5 adenoviral-vectors for gene delivery were designed and constructed to specifically target cancer cells. They are designated as "PY4-mazF-mCherry" (PY4, ras responsive element), "ΔPY4-mazF-mCherry" (control viruses) and "RGC-mazE-IRES-GFP" (RGC, P53 responsive element). Their potency was tested in vitro, by the enzymatic MTT assay, microscopic observation, colony formation assay and FACS analysis, and in a xenograft model of CRC. Next, we generated, small natural vesicles, exosomes, that directly targeted cancer through specific small antibody fragments against CD24 that is expressed in most cancer cells and rarely on normal cells. Results: The TA system ("PY4-mazF-mCherry"+"RGC-mazE-IRES-GFP") induced a massive cell death, in a dose-dependent manner in vitro, 69% as compared to 19% in control co-infected ("ΔPY4-mazF-mCherry"+"RGC-mazE-IRES-GFP") HCT116 CRC cells (mutated RAS and p53). In vivo, growth of HCT116-/- ( KRASmutand P53mut) and HCT116+/+ ( KRASmut and P53wt) tumors were significantly inhibited (70% and 65%, respectively). Conclusions: 1. Abusing the P53 genetic status and the activated Ras pathway holds promising effective and safe strategy to target tumor cells while sparing normal tissues. 2. It is a proof of concept for personalized cancer therapy based on the tumor genetic profile.

Abstract 1480: Mir-182 is involved in sulindac anticancer activity in colon cancer

Abstract Nonsteroidal anti-inflammatory drugs (NSAIDs) display promising antineoplastic activity in many human solid tumors including colorectal cancer. Previous studies reported that sulindac sulfide (SS) can inhibit the growth of tumor cells through cyclooxygenase-2 (COX-2) dependent or independent pathways. Obviously, COX-2 independent pathway involves a low toxic property to support the clinical potential for using sulindac as a chemoprevention drug. However, the molecular mechanisms responsible for COX-2 independent pathway have not been completely elucidated. In this project, we employed two human colon cancer cell lines, referred to HCT116 and HT29. HCT116 cells are characterized for low COX-2 expression, while HT29 cells show relatively high COX-2 expression. We found that SS could unbiasedly inhibit the growth of HCT116 and HT29 cells by arresting cells in G1/G2 phases. CyclinG2 was found to be upregulated in response to SS treatment. FOXO3a has been reported to regulate CyclinG2 expression at the transcriptional level. Our results demonstrate that SS could also upregulate FOXO3a. By using the loss-of-function strategy, we found that SS could not efficiently upregulate CyclinG2 and lead to cell cycle arrest in cells with FOXO3a knockdown. In addition, we studied the mechanism that could be involved in SS regulation of FOXO3a. Our previous studies reported that a panel of miRNAs could be altered by SS treatment in both colon and breast cancer cells. In the downregulated miRNA list, we found that miR-182 could potentially target FOXO3a. By using luciferase assay, we validated the direct regulation of miR-182 on the expression of FOXO3a. When miR-182 was downregulated, SS could neither efficiently upregulate the expression of FOXO3a nor inhibit cell growth as it did in control cells. We gained highly consistent results in HT29 and HT29 cells with COX-2 knockdown. Therefore, our study demonstrates a pathway consisting of miR-182/ FOXO3a/ CyclinG2 as a novel mechanism responsible for SS anticancer activity in colon cancer, which may imply a COX-2 independent pathway. Citation Format: Hongyou Zhao, Bin Yi, Zhipin Liang, Ruixia Ma, Yaguang Xi. Mir-182 is involved in sulindac anticancer activity in colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1480. doi:10.1158/1538-7445.AM2017-1480

Analysis of the Cytotoxic Effects of Vitamin D3 on Colorectal, Breast and Cervical Carcinoma Cell Lines

Although evidences from epidemiological suggested possible involvement of vitamin D in the prevention and treatment of cancers, it is not fully known how vitamin D inhibits cancer cell growth. Recent studies have shown that 1,25-(OH)2D inhibits cancer cell proliferation by binding to vitamin-D receptor (VDR). The vitamin D - VDR complex in turn (a) upregulate cell cycle inhibitors p21 and p27; (b) promote apoptosis mediators caspase-3 and 7, Bad, p53 and PTEN; (c) arrest cells in senescence phase; (d) elevate cell differentiation; and (e) inhibit IGF signaling. Moreover, vitamin D reduces reactive oxygen species (ROS) there by prevents the progression of cancer cells. However, it is currently unknown whether vitamin D induced cancer cell death is mediated by its effect on ROS destroying Nrf2 signaling. In addition, it is also not known whether withdrawal of glucose improves the efficacy of vitamin D as presence of excess glucose promotes ROS in cancer cells. Therefore, first, efficacy of vitamin D for inhibiting the growth of cell lines HCT116, HeLa and MCF-7 was determined. Next, the effect of vitamin D on Nrf2 expression and activity in the presence and absence of glucose was assessed. The data showed that vitamin D inhibited the growth of HCT116, HeLa and MCF-7 cells in a dose dependent manner with more potency toward HCT116. Vitamin D reduced the levels of Nrf2 and NQO1 expression when HCT116 cells were treated in glucose lacking medium. But, despite a significant reduction in cell viability, no change in the Nrf2 expression was observed if the HCT-116 cells were treated with vitamin D dissolved in high glucose (4.5g/L) containing DMEM. Therefore, it is concluded that the cell growth inhibition by vitamin D, observed in the presence of glucose, is not at least mediated by Nrf2 modulation in HCT116 cells.

173 The Absence of NHERF2 Attenuates Colon Cancer Growth

Background and Aims: Identification of new molecular targets is needed for better clinical care of colorectal cancer (CRC) patients. Na+/H+ exchanger regulatory factor 2 (NHERF2) was initially identified as a scaffold protein of NHE3, but NHERF2 interacts with a larger number of proteins and overexpression of NHERF2 in CRC has been reported. NHERF2 functions as a modulator of phospholipase Cβ and interacts with lysophosphatidic acid receptor type 2 (LPA2) to enhance LPA-dependent colon cancer cell growth in culture. We have previously shown that loss of LPA2 attenuates colon cancer progress in vivo. However, the importance of NHERF2 in cancer has not been studied and it is unclear whether the role of NHERF2 is limited to LPA2-dependent effects. The aim of the present work was to examine the role of NHERF2 in colonic tumor growth. Methods: HCT116 cells with stable knockdown of NHERF2 (shNHERF2), LPA2 (shLPA2) or control (shCont) were generated. The effects of NHERE2 knockdown on HCT116 cell growth was determined in vitro and in a xenograft model. The effects NHERF2 knockdown was compared with LPA2 knockdown. Apcmin/+ mice were crossed with Nherf2-/mice and the growth and number of intestinal tumors were determined in Apcmin/+, Apcmin/+;Nherf2+/-, and Apcmin/+;Nherf2-/mice. Results: Knockdown of NHERF2 significantly decreased the rates of cell proliferation in the presence of 1-10% FBS. Similarly, the rates of xenograft tumor growth of HCT116/ shNHERF2 cells were constantly slower compared with HCT116/shCont cells. Ki-67 staining of the xenografts confirmed the difference in tumor growth between shNHERF2 and shCont cells. Similar difference was obtained between shLPA2 and shCont cells. Intestinal tumor size was significantly smaller in Apcmin/+;Nherf2-/mice compared to Apcmin/+ mice. In contrast, there was no significant difference in the number of tumors between Apcmin/ +;Nherf2-/and Apcmin/+ mice. As a comparison, we reported earlier that both tumor numbers and sizes were decreased in Apcmin/+;Lpa2-/mice. To understand the molecular basis of NHERF2 depletion on colon cancer, we compared transcriptional profiling of control, shNHERF2 and shLPA2 xenograft cells by RNAseq. We found that expression of 549 and 778 genes in the shNHERF2 and shLPA2 cells, respectively, were altered (p< 0.05) compared with control. Interestingly, only 190 genes were altered in both shNHERF2 and shLPA2 cells, with 359 genes in the shNHERF2 and 588 genes in the shLPA2 cells uniquely regulated. Conclusion: Loss of NHERF2 attenuated tumor growth in both Apcmin/+ and xenograft models of colon cancer. Profile of dysregulated genes in NHERF2 deficient tumors indicates that the role of NHERF2 in tumor progress is potentially diverse and not limited to LPA signaling. This study highlights NHERF2 as a novel oncogenic factor and potential target for CRC treatment.

174 The RNA-Binding Protein Tristetraprolin Controls Intestinal Cell Differentiation and Tumorigenesis Through the Notch Pathway

Background and Aims: Identification of new molecular targets is needed for better clinical care of colorectal cancer (CRC) patients. Na+/H+ exchanger regulatory factor 2 (NHERF2) was initially identified as a scaffold protein of NHE3, but NHERF2 interacts with a larger number of proteins and overexpression of NHERF2 in CRC has been reported. NHERF2 functions as a modulator of phospholipase Cβ and interacts with lysophosphatidic acid receptor type 2 (LPA2) to enhance LPA-dependent colon cancer cell growth in culture. We have previously shown that loss of LPA2 attenuates colon cancer progress in vivo. However, the importance of NHERF2 in cancer has not been studied and it is unclear whether the role of NHERF2 is limited to LPA2-dependent effects. The aim of the present work was to examine the role of NHERF2 in colonic tumor growth. Methods: HCT116 cells with stable knockdown of NHERF2 (shNHERF2), LPA2 (shLPA2) or control (shCont) were generated. The effects of NHERE2 knockdown on HCT116 cell growth was determined in vitro and in a xenograft model. The effects NHERF2 knockdown was compared with LPA2 knockdown. Apcmin/+ mice were crossed with Nherf2-/mice and the growth and number of intestinal tumors were determined in Apcmin/+, Apcmin/+;Nherf2+/-, and Apcmin/+;Nherf2-/mice. Results: Knockdown of NHERF2 significantly decreased the rates of cell proliferation in the presence of 1-10% FBS. Similarly, the rates of xenograft tumor growth of HCT116/ shNHERF2 cells were constantly slower compared with HCT116/shCont cells. Ki-67 staining of the xenografts confirmed the difference in tumor growth between shNHERF2 and shCont cells. Similar difference was obtained between shLPA2 and shCont cells. Intestinal tumor size was significantly smaller in Apcmin/+;Nherf2-/mice compared to Apcmin/+ mice. In contrast, there was no significant difference in the number of tumors between Apcmin/ +;Nherf2-/and Apcmin/+ mice. As a comparison, we reported earlier that both tumor numbers and sizes were decreased in Apcmin/+;Lpa2-/mice. To understand the molecular basis of NHERF2 depletion on colon cancer, we compared transcriptional profiling of control, shNHERF2 and shLPA2 xenograft cells by RNAseq. We found that expression of 549 and 778 genes in the shNHERF2 and shLPA2 cells, respectively, were altered (p< 0.05) compared with control. Interestingly, only 190 genes were altered in both shNHERF2 and shLPA2 cells, with 359 genes in the shNHERF2 and 588 genes in the shLPA2 cells uniquely regulated. Conclusion: Loss of NHERF2 attenuated tumor growth in both Apcmin/+ and xenograft models of colon cancer. Profile of dysregulated genes in NHERF2 deficient tumors indicates that the role of NHERF2 in tumor progress is potentially diverse and not limited to LPA signaling. This study highlights NHERF2 as a novel oncogenic factor and potential target for CRC treatment.

Evaluation of New Naphthalimides as Potential Anticancer Agents against Breast Cancer MCF-7, Pancreatic Cancer BxPC-3 and Colon Cancer HCT- 15 Cell Lines

New 1,8-naphthalimido derivatives with 2,3 and 4 carbon chains bearing a number of different functionalities were synthesized and tested against a panel of breast cancer MCF-7, colon cancer HCT-15 and pancreatic cancer BxPC-3 cell lines. Generally structures with shorter alkyl chains were more active, with the one exception of the amide containing a p-nitrophenyl group. GI50 values (μM) were determined for the most active compounds. Three compounds exhibited GI50 values below 5 μM, two with MCF-7 cells, and one other with HCT-15. Compounds with different functionalities demonstrated cell line specificity: the MCF-7 cell line was more sensitive to an urea derivative (6f), the growth of HCT- 15 cells were most affected by a triazole (9d), while the BxPC-3 cell line was inhibited in a higher extend by a guanidine (4a).

P98 Tetracyclin antibiotics as inhibitors of H2S synthesis

Hydrogen sulfide (H2S) has emerged as a gaseous signaling molecule with important roles in neuromodulation, blood pressure regulation, angiogenesis, cardioprotection, cellular energetics and apoptosis. H2S is produced endogenously by three enzymes in the sulfur metabolic network, namely cystathionine beta synthase (CBS), cystathionine gamma lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3MST). Although several compounds that inhibit CSE are available, no selective inhibitors for CBS or 3MST currently exist. In the present study we screened the LOPAC library for inhibitors of H2S-producing enzymes. The methylene blue assay was used to measure H2S production from recombinant enzymes. HCT116 and HT29 cells were used for MTT-based proliferation assays. Screening of the LOPAC library yielded several hit compounds that blocked H2S-synthesizing enzymes to varying extents. Among those, doxycyclin and demeclocycline were found to inhibit 3MST by approximately 50% at 100 uM, with doxycyclin being a more potent 3MST inhibitor than demeclocycline in the in vitro activity assay. Tetracyclin, meclocyclin, oxycyclin, methacyclin, tigecyclin and minocyclin did not affect 3MST activity when used up to 300 uM. From the above-mentioned tetracyclines, tigecyclin at 100 uM caused only a slight inhibition of both CBS and CSE; tigecyclin additionally inhibited CSE. In a cell-based assay, demeclocyclin, but not doxycyclin, inhibited the growth of HCT116 and HT29, two colon cancer cell lines in which CBS is highly expressed and its product, H2S supports cell proliferation. We conclude that based on its selectivity towards 3MST, demeclocyclin could serve as a lead compound that after undergoing optimization could yield future selective 3MST inhibitors.

Novel Liposomes Composed of Dimyristoylphosphatidylcholine and Trehalose Surfactants Inhibit the Growth of Tumor Cells along with Apoptosis

Novel liposomes composed of L-α-dimyristoylphosphatidylcholine (DMPC) and trehalose surfactant (DMTre) were produced and inhibitory effects of DMTre on the growth of human colon carcinoma (HCT116) and gastric carcinoma (MKN45) in vitro were examined. The remarkably high inhibitory effects of DMTre on the growth of HCT116 and MKN45 cells were obtained without affecting the growth of normal cells. The thickness of fixed aqueous layer of DMTre was larger than that of DMPC liposomes and increased in a dose-dependent manner. The induction of apoptosis by DMTre was revealed on the basis of flow cytometric analysis. DMTre induced apoptosis through the activation of caspases and mitochondria via Bax. It is noteworthy that remarkable inhibitory effects of DMTre on the growth of human colon and gastric carcinoma cells leading to apoptosis were obtained for the first time.

Abstract 4610: NO-NSAIDs inhibit colon tumor cell growth by a cGMP-independent mechanism

Abstract Nitric oxide-releasing NSAIDs (NO-NSAIDs) were originally developed as prodrugs to reduce the gastrointestinal toxicity of conventional NSAIDs and were found to have improved potency to inhibit tumor growth compared with the parent NSAID. Although different mechanisms have been proposed for their potent anticancer properties, the role of the NO-moiety has not been clearly defined. We have investigated whether the NO group contributes to the anticancer properties of NO-NSAIDs by inducing soluble guanylyl cyclase and elevating intracellular cGMP levels, effects that are associated with the activity of NO donors. We confirmed the increased potency of the NO-derivatives of sulindac, aspirin (o-, p- and m- isomers), exisulind and naproxen with respect to the parent compounds for inhibiting growth of HCT116, SW480 and COLO741 human colon tumor cells. The two derivatives with the lowest IC50 values, NO-sulindac (16.50 µM) and NO-ASA(o) (8 µM) were also tested for cGMP elevation using a novel cGMP biosensor assay in live cells. In brief, HEK293 cells were transfected with a biosensor construct containing cGMP binding domains fused to the modified firefly luciferase gene (Promega) which produces bioluminescence in the cGMP-bound or ‘activated’ state. Cells were treated with NO-Sulindac, NO-ASA(o) and known NO-donors, NOR-3 and SNP as positive controls. Chemiluminescence was measured over a period of 1h. A strong and sustained signal was obtained with the NO-donors, SNP and NOR-3 (50 µM), although no induction was observed with NO-NSAID treatment (50 µM). In addition, SW480 colon tumor cells were treated with 50 µM NO-Sulindac, NO-ASA(o) or NOR-3 and levels of phosphorylated vasoactivator stimulated phosphoproteins (p-VASP), an intracellular marker of cGMP signaling activity, were measured by Western Blotting. NOR-3 caused a time-dependent increase in p-VASP expression, whereas the NO-NSAIDs had no such effect. Since sulindac and certain derivatives have previously been reported to inhibit cGMP-phosphodiesterase (PDE) and inhibit tumor cell growth by a mechanism involving cGMP elevation, we also determined if NO-NSAIDS can inhibit cGMP PDE activity. NO-NSAIDs did not inhibit cGMP hydrolysis by either recombinant PDE5 or in lysates from colon tumor cells, although sulindac sulfide was an effective inhibitor as previously reported. These results suggest that mechanisms other than cGMP elevation explain the anticancer properties of NO-NSAIDs. Funding provided by NIH/NCI grants CA131378 and CA148817. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4610. doi:10.1158/1538-7445.AM2011-4610

Colon Cancer Proliferating Desulfosinigrin in Wasabi (Wasabia japonica)

A reduced incidence of different types of cancer has been linked to consumption of Brassica vegetables, and there is evidence that glucosinolates (GSLs) and their hydrolysis products play a role in reducing cancer risk. Wasabi (Wasabia japonica) and horseradish (Armoracia rusticana), both Brassica vegetables, are widely used condiments both in Japanese cuisine and in the United States. Desulfosinigrin (DSS) (1) was isolated from a commercially available wasabi powder and from fresh wasabi roots. Sinigrin (2) was isolated from horseradish roots. DSS and sinigrin were evaluated for their inhibitory effects on cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes, on lipid peroxidation, and on the proliferation of human colon (HCT-116), breast (MCF-7), lung (NCI H460), and central nervous system (CNS, SF-268) cancer cell lines. DSS did not inhibit COX enzymes or lipid peroxidation at 250 mg/ml. Sinigrin inhibited lipid peroxidation by 71% at 250 μg/ml. However, DSS promoted the growth of HCT-116 (colon) and NCI H460 (lung) human cancer cells as determined by the MTT assay in a concentration-dependent manner. At 3.72 μg/ml, a 27% increase in the number of viable human HCT-116 colon cancer cells was observed; the corresponding increases at 7.50 and 15 μg/ml were 42 and 69%, respectively. At 60 μg/ml, DSS doubled the number of HCT-116 colon cancer cells. For NCI H460 human lung cancer cells, DSS at 60 μg/ml increased the cell number by 20%. Sinigrin showed no proliferating effect on the tumor cells tested. This is the first report of the tumor cell-proliferating activity by a desulfoglucosinolate, the biosynthetic precursor of GSLs found in Brassica spp.