Carcinoma SW480 Cells Research Articles

Honokiol inhibits proliferation of colorectal cancer cells by targeting anoctamin 1/TMEM16A Ca2+ -activated Cl- channels.

Ca2+ -activated Cl- channels (Ano1 channels) contribute to the pathogenesis of colorectal cancer. Honokiol is known to inhibit cell proliferation and tumour growth in colorectal cancer. However, the molecular target of honokiol remains unclear. This study aimed to investigate whether honokiol inhibited cell proliferation of colorectal cancer by targeting Ano1 channels. Patch-clamp techniques were performed to study the effect of honokiol on Ca2+ -activated Cl- currents in HEK293 cells overexpressing Ano1- or Ano2-containing plasmids or in human colorectal carcinoma SW620 cells. Site-directed mutagenesis was used to identify the critical residues for honokiol-induced Ano1 inhibition. Proliferation of SW620 cells or human intestinal epithelial NCM460 cells by CCK-8 assays. Honokiol blocked Ano1 currents in Ano1-overexpressing HEK293 cells and SW620 cells. Honokiol more potently inhibited Ano1 currents than Ano2 currents. Three amino acids (R429, K430 and N435) were critical for honokiol-induced Ano1 inhibition. The R429A/K430L/N435G mutation reduced the sensitivity of Ano1 to honokiol. Honokiol inhibited SW620 cell proliferation, and this effect was reduced by Ano1-shRNAs. Furthermore, Ano1 overexpression promoted proliferation in NCM460 cells with low Ano1 endogenous expression and resulted in an increased sensitivity to honokiol. Overexpression of the R429A/K430L/N435G mutation reduced WT Ano1-induced increase in the sensitivity of NCM460 cells to honokiol. We identified a new anticancer mechanism of honokiol, through the inhibition of cell proliferation, by targeting Ano1 Ca2+ -activated Cl- channels.

TSP-1 as a novel biological marker of tumor vasculature normalization in colon carcinoma induced by Endostar.

Blood vessels in tumors often exhibit abnormal morphology and function, which promotes the growth, metastasis and resistance of tumors to conventional therapies. Therefore, vascular normalization is an emerging strategy to enhance the effectiveness of radiotherapy and chemotherapy when used in combination; however, there is a lack of evidence regarding the optimal schedule for the co-administration of anti-angiogenic and chemotherapeutic drugs. Scheduling treatment is important as the period for normalization is transient, also known as the ‘time window’; however, no biomarker has been identified to detect this window. In the present study, recombinant human endostatin (rhES) was employed as an anti-angiogenic agent in xenograft tumor tissue in mice. Following rhES or control (saline) treatment, the density and integrity of tumor vessels were detected by immunofluorescence staining for cluster of differentiation 31 and α-smooth muscle actin; the level of hypoxia in tumor tissue was examined by immunohistochemistry with pimonidazole; the necrotic area was evaluated by hematoxylin and eosin staining; and the level of thrombospondin-1 (TSP-1) in plasma was tested by ELISA. The Cell Counting Kit-8 assay was also used to evaluate the effect of rhES on the proliferation of colon carcinoma SW620 cells. A ‘time window’ normalized vasculature was determined between day 4 and 6 following rhES treatment, and accompanied by a decrease in hypoxia in tumor tissue. Decreasing plasma TSP-1 levels were consistent with changes in vascular morphology and hypoxia, which exhibited features of normalization. In addition, rhES had no effect on the proliferation of SW620 cells, suggesting that the reduction in TSP-1 was associated with increased oxygen content during vascular normalization, rather than inhibited cell proliferation. In conclusion, TSP-1 may be a potential biomarker for predicting the normalization window of colon cancer vessels.

Down-regulation of miR-29a facilitates apoptosis of colorectal carcinoma cell SW480 and suppresses its Paclitaxel resistance.

PTEN can suppress PI3K/AKT activity, and regulate cell proliferation, apoptosis, and drug resistance. The previous study showed that up-regulation of miR-29a played an essential role in the occurrence of colorectal carcinoma. This study aimed to investigate the role and related mechanism of miR-29a in mediating Paclitaxel sensitivity of colorectal carcinoma cells. Bioinformatics analysis was performed to study the existence of binding sites between miR-29a and targeting gene mRNA. Dual luciferase reporter assay was conducted to validate the targeted regulation. The expressions were compared between CCD841 CoN cells, colorectal carcinoma cell line SW480, and drug-resistant cell line SW480/Paclitaxel. Cell apoptosis and proliferation were measured by flow cytometry. In vitro cultured SW480/Paclitaxel cells were transfected with miR-29a or pcDNA3.1-PTEN. MiR-29a and PTEN expressions were measured by quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) and Western blot, followed by flow cytometry on the detection of cell apoptosis as well as proliferation assay. A targeted regulatory relationship existed between miR-29a and PTEN. Comparing to CCD841 CoN cells, high level of miR-29a and decreasing expression of PTEN were found in SW480 cells. Moreover, further higher miR-29a and lower PTEN expressions were observed in SW480/Paclitaxel cells. Paclitaxel remarkably inhibited proliferation and facilitated apoptosis of SW480 cells but not SW480/Paclitaxel cells. Transfection of miR-29a inhibitor or pcDNA3.1-PTEN remarkably elevated PTEN expression, suppressed p-AKT expression, weakened proliferation, and enhanced apoptosis of SW480/Paclitaxel cells. Our data demonstrated that suppression of miR-29a enhanced PTEN expression, inhibited cancer cell proliferation, facilitated apoptosis, and weakened drug resistance, which provides academic basis for the treatment of colorectal cancer.

Harmine induces cell cycle arrest and mitochondrial pathway-mediated cellular apoptosis in SW620 cells via inhibition of the Akt and ERK signaling pathways.

Harmine, a β-carboline alkaloid isolated from the seeds of Peganum harmala, possesses both antitumor and anti‑nociceptive effects and inhibits human DNA topoisomerase. However, no detailed data are available concerning the mechanisms of harmine in human colorectal carcinoma SW620 cells. In the present study, we demonstrated that harmine inhibited the proliferation of SW620 cells in a dose-dependent manner using MTT and clone formation assays, and the IC50 value of harmine on the growth inhibition of SW620 cells for 48h was 5.13µg/ml. PI staining showed that harmine altered the cell cycle distribution by decreasing the proportion of cells in the G0-G1phase and increasing the proportion in the Sand G2-Mphase. The expression level of cyclinD1 was decreased, while the expression of cyclinA, E2andB1, CDK1/cdc2, Myt-1 and p-cdc2(Tyr15) were increased, which was in accordance with the S and G2/Mphase arrest. Hoechst33258 staining revealed nuclear fragmentation, chromosomal condensation and cell shrinkage in the SW620 cells treated with harmine. Flow cytometry revealed that the percentage of apoptotic sub-G1 cells increased from 7.19 to 26.58%, while in the control group, sub-G1 cells only increased from 1.53 to 1.60%. Furthermore, early and late apoptotic cells were increased from 11.96 to 26.38% when incubated with the indicated concentration of harmine for 48h, while in the control group, <8% of cells underwent apoptosis. JC-1 staining revealed that harmine decreased mitochondrial transmembrane potential (ΔΨm). The apoptosis of SW620 cells was also detected by western blot analysis, showing caspase-3and-9, and PARP activation; the downregulation of Bcl-2, Mcl-1, Bcl-xL; and the upregulation of Bax. The expression of p-ERK, p-Akt (Ser473) and p-Akt (Thr308) was inhibited, and phosphorylation of downstream targets of Akt, such as p-FoxO3a and p-GSK‑3β were also attenuated. In conclusion, harmine induces cell cycle arrest and mitochondrial pathway-mediated cellular apoptosis in SW620 cells via inhibition of the Akt and ERK signaling pathways.

In situ targeting TEM8 via immune response and polypeptide recognition by wavelength-modulated surface plasmon resonance biosensor.

There is an increasing interest in real-time and in situ monitoring of living cell activities in life science and medicine. This paper reports a whole cell sensing protocol over the interface of Au film coupled in a wavelength-modulated surface plasmon resonance (WMSPR) biosensor. With dual parabolic mirrors integrated in the sensor, the compact and miniaturized instrument shows satisfactory refractive index sensitivity (2220 nm/RIU) and a high resolution of resonance wavelength shift of 0.3 nm to liquid samples. The affinity interactions between the biomarker of human tumor endothelial marker 8 (TEM8) and antibody (Ab) or specific polypeptide (PEP) were firstly introduced to WMSPR biosensor analysis. Both the interaction events of Ab-cell and PEP-cell over the Au film interface can be recognized by the sensor and the balance time of interactions is about 20 min. The concentration range of Ab for quantitative monitoring of the TEM8 expression on human colon carcinoma SW620 cells was investigated. The present low-cost and time-saving method provides a time resolution of binding specificity between Ab/PEP and TEM8 for real-time analysis of antigen on living tumor cell surface.

Effect of DR-nm23 overexpression on biological characteristics of human colorectal carcinoma SW620 cells

Effect of DR-nm23 overexpression on biological characteristics of human colorectal carcinoma SW620 cells

Influence of the oncolytic parvovirus H-1, CTLA-4 antibody tremelimumab and cytostatic drugs on the human immune system in a human in vitro model of colorectal cancer cells

IntroductionTumor-directed and immune-system-stimulating therapies are of special interest in cancer treatment. Here, we demonstrate the potential of parvovirus H-1 (H-1PV) to efficiently kill colorectal cancer cells and induce immunogenicity of colorectal tumors by inducing maturation of dendritic cells (DCs) alone and also in combination with cytostatic drugs in vitro. Using our cell culture model, we have additionally investigated the effects of anti-CTLA-4 (cytotoxic T-lymphocyte-associated antigen 4) receptor antibody tremelimumab on this process.Materials and methodsColon carcinoma cell lines were treated with different concentrations of cytostatic drugs or tremelimumab or were infected with H-1PV in different multiplicities of infection (MOIs), and viability was determined using MTT assays. Expression of CTLA-4 in colon carcinoma cell lines was measured by FACScan™. For the coculture model, we isolated monocytes using adherence, and differentiation into immature DCs (iDCs) was stimulated using interleukin-4 and granulocyte-macrophage colony-stimulating factor. Maturation of iDCs into mature DCs (mDCs) was induced by a cytokine cocktail. SW480 colon carcinoma cells were infected with H-1PV or treated with cytostatic drugs. Drug treated and H-1PV-infected SW480 colon carcinoma cells were cocultured with iDCs and expression of maturation markers was measured using FACScan™. Cytokine measurements were performed using enzyme-linked immunosorbent assay.ResultsColon carcinoma cells SW480 were potently infected and killed by H-1PV. CTLA-4 expression in SW480 cells increased after infection with H-1PV and also after treatment with cytostatic drugs. Tremelimumab had no influence on viability of the colon carcinoma cell line. There was no maturation of iDCs after coculture with SW480; instead, H-1PV-infected or drug pretreated SW480 induced maturation. Cytokine production was higher for H-1PV-infected cells but was not significantly enhanced by tremelimumab treatment alone or in combination. Addition of tremelimumab did not interfere with the maturation process as measured by markers of maturation as well as by determination of cytokine levels.ConclusionBy enhancing both cell death and immunogenicity of tumors, H-1PV is of special interest for tumor-directed therapy. These features make it a promising candidate for clinical application in human colorectal cancer. As tremelimumab does not significantly interfere with this process, an interesting therapeutic combination of active enhancement of tumor immunogenicity and independent masking of the CTLA-4 silencing process on tumor cells is highlighted.

Abstract 2017: Galectin-3 SNP rs10148371 in the anti-death motif NWGR is related to the colon cancer incidence in African Americans

Abstract Survival after cancer diagnosis is poorer for African Americans than for Caucasians. While some of this survival difference is driven by differences in the stage at diagnosis, even within the stage this trend is evident. For example, 5-year relative survival for colorectal cancer diagnosed as regional stage is 68.5% for Caucasians and only 60.6% for African Americans. Little is known about racial differences in response to chemotherapy and the subsequent impact on survival. A number of recent reports have focused on single nucleotide polymorphisms (SNPs) with the notion that such genetic event(s) can/may contribute to cancer development or progression. We have identified a SNP, rs10148371, which results in the substitution of R183K in the NWGR anti-death motif of the galectin-3 gene. Galectin-3, belonging to the family of carbohydrate-binding galectins is a multi-function tumor associated protein, which regulates cell growth, cell proliferation, cell adhesion, angiogenesis and apoptosis. It contains the NWGR motif characteristic of BH1 domain of Bcl-2 family responsible for protecting cells from apoptosis. To understand the significance of this SNP, we generated point mutation G548 to A in galectin-3 cDNA leading to R183K substitution. The resulting cDNA was stably transfected into low galectin-3 expressing colon carcinoma cells SW480 and RKO. Selected clones were analyzed for cell survival and apoptotic potential against cisplatin, 5 fluoro-uracil and oxaliplatin. The clones containing mutated galectin-3 showed a higher susceptibility to apoptosis compared to the wild type galectin-3. The WT clones showed an up-regulation of β-catenin and its downstream target proteins, which was not seen in the mutant clones. Ability/inability of mutated galectin-3 in the nuclear translocation of β-catenin is being studied. The racial distribution of the SNP rs10148371 in the normal population of the African Americans is 22%, while in Caucasians and Asians disease free population it can be found in less than 1%. To analyze the significance of this SNP in relation to breast and colorectal cancer, we performed genotype analysis with breast cancer (N=124) or colorectal cancer (N=129) patients. Stratified analyses revealed that the Lys variant was marginally significantly inversely associated with advanced tumor stage (p=0.08) and younger (&amp;lt;50 years for breast cancer and &amp;lt;60 years for colorectal) onset (p=0.05). However, survival did not show that this variant was associated with the risk of overall deaths (hazard ratio 0.79 (95% confidence interval: 0.40-1.56)). Next, we analyzed if the variations in genotype distribution can be related to sex in colorectal cancer. We saw a significant increase in the percent of Lysine harboring males with colorectal cancer. The Chi-Square probability was 0.0509. Albeit not a dramatic difference but certainly suggestive, which will require further study. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2017. doi:1538-7445.AM2012-2017

A paraptosis-like cell death induced by δ-tocotrienol in human colon carcinoma SW620 cells is associated with the suppression of the Wnt signaling pathway

Tocotrienol is considered a beneficial effect agent on inhibition of tumor development. In this study, we focused on the effects of δ-tocotrienol and its possible mechanism on induction of death in human colon cancer SW620 cells. δ-Tocotrienol inhibited proliferation of SW620 cell in a dose-dependent manner. Our findings showed that δ-tocotrienol effectively induced paraptosis-like death in SW620 cells, correlated with the vacuolation that may be from welling and fusion of mitochondria and/or the endoplasmic reticulum (ER) as well as caspase-3 nonactivated. However, there were no changes in apoptosis based on flow cytometry analysis. Of being noted, δ-tocotrienol reduced the expression of β-catenin and wnt-1 proteins by about 50% at the highest dose (20 μmol/L). δ-Tocotrienol also decreased cyclin D1, c-jun and MMP-7 protein levels in SW620 cells. Altogether, these data indicate that δ-tocotrienol induces paraptosis-like cell death, which is associated with the suppression of the Wnt signaling pathway. Thus, our findings may provide a novel application in treatment of human colon carcinoma.

Construction of a lentiviral vector carrying the DR-nm23 gene and its stable expression in colorectal carcinoma SW620 cells

Construction of a lentiviral vector carrying the DR-nm23 gene and its stable expression in colorectal carcinoma SW620 cells

Killing effect of interleukin-18-enhanced FasL-expressing colon cancer cells on human hepatocytes in vitro

To investigate the influence of mutual interactions between FasL expressed by colon carcinoma cells and endogenous cytokines interleukin-18 on liver metastasis and invasion of human colon cancer cells. Using immunohistochemical streptavidin-biotin complex (SABC) method, the expressions of Fas receptor and Fas ligand in SW620 colon carcinoma cells and Chang liver cells were observed so as to provide morphological evidence for the functions of Fas receptor and Fas ligand. In an effort to examine the cytotoxicity of effector cells, CytoTox(96) Non-Radioactive Cytotoxicity Assay was adopted to measure the LDH releasing value after the SW620 cells were co-cultured with Chang liver cells. It was shown that the Fas ligand of colon carcinoma SW620 cells was positive and the positive substances were distributed in the cell membrane and cytoplasm, and the Fas receptor of colon carcinoma SW620 cells was negative. The Fas receptor of Chang liver cells turned out to be positive and the positive substances were distributed in the cell membrane, and the Fas ligand of Chang liver cells was negative. At 6 hours after co-culture of IFN-γ-stimulated Chang liver cells with interleukin-18-stimulated (for 36 h) SW620 cells or unstimulated SW620 cells, the cytotoxicity of SW620 cells to IFN-stimulated Chang liver cells at effector-to-target ratios of 10:1, 5:1, 2.5:1 and 1.25:1 was 68.3%, 49.8%, 21.1%, 9.7% (F = 76.87, P < 0.05) and 32.7%, 21.8%, 11.1%, 6.7% (F = 7.27, P < 0.05), respectively. The non-radioactive cytotoxicity assay showed that the apoptotic rate of Chang liver cells was remarkably increased with the increase of planting concentration of SW620 after the SW620 cells were co-cultured with Chang liver cells. The cytotoxicity was significantly enhanced by interleukin-18. The FasL expression of human colon cancer cells may be regulated by endogenous interleukin-18 in the host microenvironment and enhance the liver colonization competence of colon cancer cells through induction of apoptosis in the Fas-expressing hepatocytes.

Pro-apoptotic effects of lowbush blueberry proanthocyanidins in human colon carcinoma SW480 and SW620 cells

Pro-apoptotic effects of lowbush blueberry proanthocyanidins in human colon carcinoma SW480 and SW620 cells

Characterization of Functional Domains Necessary for Mutant p53 Gain of Function

Tumor cells, including SW480 carcinoma cells that carry a mutant p53, are addicted to the mutant for their survival and resistance to growth suppression by chemotherapeutic agents. Here, we investigated whether various classes of p53 mutants share a common property and functional domains necessary for mutant p53 gain of function. To test this, we generated SW480 cell lines in which endogenous mutant R273H/P309S can be inducibly or stably knocked down, whereas a small interfering RNA-resistant mutant p53 along with a mutated functional domain can be inducibly or stably expressed. We found that both contact-site (R248W and R273H) and conformation (G245S and R249S) mutants are able to maintain the transformed phenotypes of SW480 cells conferred by endogenous mutant p53. We also found that activation domains 1-2 and the proline-rich domain are required for mutant p53 gain of function. Interestingly, we showed that the C-terminal basic domain, which is required for wild-type p53 activity, is an inhibitory domain for mutant p53. Furthermore, we showed that deletion of the basic domain enhances, whereas a mutation in activation domains 1-2 and deletion of the proline-rich domain abolish mutant p53 to regulate Gro1 and Id2, both of which are regulated by and mediate endogenous mutant p53 gain of function. These results indicate that both conformation and contact-site mutants share a property for cell transformation, and the domains critical for wild-type p53 tumor suppression are also required for mutant p53 tumor promotion. Thus, the inhibitory basic domain and the common property for p53 mutants can be explored for targeting tumors with mutant p53.

Expression and Functional Research of TLR4 in Human Colon Carcinoma

IntroductionTo verify whether human colon carcinoma cells can express Toll-like receptor 4 (TLR4) and investigate the biological function of TLR4 on human colon carcinoma cells. MethodsHuman colon carcinoma cells SW480 was cultured with RPMI 1640 medium. The expression of TLR4 was analyzed by reverse transcription polymerase chain reaction and quantified by flow cytometry. Cell proliferation was evaluated by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay. The production of transforming growth factor-β, vascular endothelial growth factor, and interleukin-8 induced by lipopolysaccharide (LPS)-the TLR4 ligand was tested by enzyme-linked immunosorbent assay. Whether mitogen-associated protein kinases and nuclear factor-κB (NF-κB) proteins were activated was analyzed by Western blot. Apoptosis was analyzed by Annenxin V/PI staining. ResultsTLR4 is expressed on SW480 cells. LPS could not affect TLR4 expression and the proliferation of SW480 cells. LPS increased the phosphorylation of ERK1/2 and P38 and activated NF-κB. LPS promoted the production of vascular endothelial growth factor, transforming growth factor-β, and interleukin-8. In addition, LPS induced resistance of SW480 cells to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis. Furthermore, NF-κB activation was necessary for apoptosis resistance of SW480 cells induced by LPS. ConclusionsTLR4 is expressed on human colon carcinoma cells and functionally active. It may play important roles in promoting immune escape of human colon carcinoma cells by inducing immuno-suppressive factors and apoptosis resistance.

Decreasing Pin1 suppressed the properties of migratory and invasive in colorectal carcinoma SW620 cells

Objective The aim of our study was to investigate the effect of Pin1 on the expression of MMP-2 and MMP-9 in human colorectal carcinoma SW620 cells.

Evaluation of metastatic and angiogenic potentials of human colon carcinoma cells in chick embryo model systems

Increased metastatic and angiogenic potentials of aggressive human colon carcinoma cells were verified in independent chick embryo models by comparing in vivo highly metastatic SW620 colon carcinoma cell line with its isogenic, non-metastatic SW480 cell variant. In the experimental metastasis model, both cell types rapidly arrested in the chorioallantoic membrane (CAM) vasculature as demonstrated by quantitative PCR and immunohistochemistry. Live cell imaging also indicated that both SW620 and SW480 cells efficiently extravasated from the CAM capillary system. However, only few SW480 cells were present in the CAM tissue after 24-48 h. In contrast, the numbers of SW620 cells increased exponentially, indicating proliferative and survival advantages of metastatic colon carcinoma cells in vivo. Multicellular SW620 foci were identified in close proximity to CAM blood vessels. A positive correlation between increased metastatic ability and VEGF-expression of colon carcinoma SW620 cells was demonstrated by the substantial inhibitory effects of anti-VEGF treatment on the levels of metastatic colonization and density of blood vessels adjacent to tumor cell foci. Furthermore, the chick embryo angiogenesis model confirmed high levels of VEGF-dependent angiogenesis induced by SW620 cells, but not SW480 cells. Thus, chick embryo experimental metastasis and CAM angiogenesis models appear to coordinately reflect critical features of advanced colon carcinomas, i.e., the acquisition of enhanced survival and increased angiogenic potentials, both constituting critical determinants of colon cancer progression. The use of rapid and quantitative chick embryo models might provide alternative approaches to conventional mammalian model systems for screening anti-cancer agents.

Magnetic chitosan nanoparticles as a drug delivery system for targeting photodynamictherapy

Photodynamic therapy (PDT) has become an increasingly recognized alternative to cancertreatment in clinic. However, PDT therapy agents, namely photosensitizer (PS), are limitedin application as a result of prolonged cutaneous photosensitivity, poor water solubility andinadequate selectivity, which are encountered by numerous chemical therapies.Magnetic chitosan nanoparticles provide excellent biocompatibility, biodegradability,non-toxicity and water solubility without compromising their magnetic targeting.Nevertheless, no previous attempt has been reported to develop an in vivo magnetic drugdelivery system with chitosan nanoparticles for magnetic resonance imaging (MRI)monitored targeting photodynamic therapy. In this study, magnetic targeting chitosannanoparticles (MTCNPs) were prepared and tailored as a drug delivery system andimaging agents for PS, designated as PHPP. Results showed that PHPP-MTCNPscould be used in MRI monitored targeting PDT with excellent targeting andimaging ability. Non-toxicity and high photodynamic efficacy on SW480 carcinomacells both in vitro and in vivo were achieved with this method at the level of0–100 µM. Notably, localization of nanoparticles in skin and hepatic tissue was significantly less thanin tumor tissue, therefore photosensitivity and hepatotoxicity can be attenuated.

Obovatol inhibits colorectal cancer growth by inhibiting tumor cell proliferation and inducing apoptosis

Neolignans such as obovatol, honokiol, and magnolol have been previously reported to show various biological activities including anti-inflammation and antitumor effects. This is the first demonstration on the in vivo antitumor effect of obovatol on human colorectal carcinoma SW620 cells. Nude mice were implanted with SW620 cells and fed with vehicle or 5 mg/kg/d dose of obovatol for 20 days. Obovatol inhibited tumor growth that accounted for 50% decrease in tumor volume and 44.6% decrease in tumor weight at the end of the experiment without any adverse health effect. In nude mice bearing SW620-incubated tumor, obovatol exhibited more potent antitumor activity than honolkiol. In addition, DNA flow cytometric analysis shows that obovatol progresses to apoptosis as detected by flow cytometry after double staining with annexin V and propidium iodide. Thus, we suggest that obovatol is a potent inducer of cell apoptosis in SW620 cells, and a potent antitumor agent.

Uptake of Anti-Anemic Substance Ferric-Sorbitol-Citrate by Normal and Malignant Cells and Its Effects on Expression of Transferrin Receptor 1 and Ferritin

Iron-containing antianemic drug ferric-sorbitol-citrate (FSC) inhibits the proliferation of various cancer cell lines in vitro and causes a regression of experimental murine tumors in vivo but does not affect the proliferation of nonmalignant cells. Growth modification caused by FSC iron involves a diminished expression of Bcl-2 and an overexpression of p53 proto-oncogene, accompanied by an increased incidence of apoptosis. Aiming to evaluate further the activity principle of the anticancer effects of this antianemic drug, in this study, we analyzed the utilization of iron from FSC and the effects of FSC iron on transferrin receptor 1 (TfR1) and ferritin expression. Without FSC iron, all the cell lines had an equal expression of TfR1, but if cultured in FSC-supplemented medium, human colon SW620 and laryngeal carcinoma Hep cells exhibited a lower expression of TfR1-positive cells than nonmalignant Wi38 fibroblasts and pancreatic carcinoma MiaPaCa2 cells. The most sensitive to FSC iron were colon carcinoma SW620 cells, whereas Wi38 fibroblasts were not sensitive at all. Increased iron uptake by colon carcinoma cells was noticed in the first 3 hours of the incubation with FSC iron, whereas higher FSC iron concentrations and longer incubation also impaired ferritin expression in SW260 colon carcinoma cells. Thus, the anticancer ability of FSC could result from its higher initial utilization of iron and consecutive negative signal for the expression of TfR1 in tumor cells. Tumor cells containing lower amounts of ferritin are probably more sensitive to oxidative stress caused by iron overload, whereas FSC iron itself was proven to be chemically stable and did not induce lipid peroxidation.

Ubiquinol and the papaverine derivative caroverine prevent the expression of tumour‐ promoting factors in adenoma and carcinoma colon cancer cells induced by dietary fat

High consumption of dietary fat promotes colon carcinogenesis. While this effect is well known the underlying mechanism is not understood. Fatty acid hydroperoxides (LOOH) arise from unsaturated fatty acids in the presence of oxygen and elevated temperature during food processing. An approach was made starting from the assumption that LOOH are present in dietary fats as a result of boiling. LOOH undergoes homolytic cleavage in the presence of iron. We studied their effects on gene expression in colorectal tumour cells using linoleic acid hydroperoxide (LOOH) as model compound. Addition to the medium of LT97 adenoma and SW480 carcinoma cells enhanced the production of hydrogen peroxide. Both cell lines were observed to increase VEGF and COX-II expression based on mRNA. Expression of VEGF was inhibited by caroverine and ubiquinon.