Anti-colon Cancer Activity Research Articles

Rhus coriaria increases protein ubiquitination, proteasomal degradation and triggers non-canonical Beclin-1-independent autophagy and apoptotic cell death in colon cancer cells

Colorectal cancer is the fourth leading cause of cancer-related deaths worldwide. Here, we investigated the anticancer effect of Rhus coriaria extract (RCE) on HT-29 and Caco-2 human colorectal cancer cells. We found that RCE significantly inhibited the viability and colony growth of colon cancer cells. Moreover, RCE induced Beclin-1-independent autophagy and subsequent caspase-7-dependent apoptosis. Blocking of autophagy by chloroquine significantly reduced RCE-induced cell death, while blocking of apoptosis had no effect on RCE-induced cell death. Mechanistically, RCE inactivated the AKT/mTOR pathway by promoting the proteasome-dependent degradation of both proteins. Strikingly, we also found that RCE targeted Beclin-1, p53 and procaspase-3 to degradation. Proteasome inhibition by MG-132 not only restored these proteins to level comparable to control cells, but also reduced RCE-induced cell death and blocked the activation of autophagy and apoptosis. The proteasomal degradation of mTOR, which occurred only 3 hours post-RCE treatment was concomitant with an overall increase in the level of ubiquitinated proteins and translated stimulation of proteolysis by the proteasome. Our findings demonstrate that Rhus coriaria possesses strong anti-colon cancer activity through stimulation of proteolysis as well as induction of autophagic and apoptotic cell death, making it a potential and valuable source of novel therapeutic cancer drug.

Photo-catalytic, anti-bacterial, and anti-cancer properties of phyto-mediated synthesis of silver nanoparticles from Artemisia tournefortiana Rchb extract

Metal nanoparticles have largely been investigated due to their potential medicinal activities. This study demonstrates the biological properties of green-synthesized silver nanoparticles (AgNPs) by using Artemisia tournefortiana Rchb ethanol extract. Instrumentations such as ultraviolet-visible spectra analysis, high-resolution transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and Fourier transform infrared spectroscopy were used to reveal the synthesized AgNPs. Microscopic results showed that the particles were mostly spherical in shape, having an average diameter of 22.89±14.82nm. The antibacterial activity of the phyto-fabricated AgNPs was investigated by the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The in vitro cytotoxicity effect was investigated against normal human embryonic kidney (HEK293) cells and human colon adenocarcinoma cancer (HT29) cells. The apoptotic cells were identified by annexin V/PI FITC staining, and morphological assessment. The expressions of Bax and Bcl2 were evaluated by quantitative real time PCR method. The phyto-synthesized AgNPs have shown increased cell apoptosis and demonstrated dose-dependent cytotoxicity in HT29 cancer cells. Moreover, the photocatalytic activity of the phyto-synthesized AgNPs was evaluated by degradation of Coomassie Brilliant Blue G-250 under UV light exposure and these fabricated Ag nanoparticles demonstrated efficacy in degrading the dye within 60min. Overall, the present results highlighted the antibacterial and anticancer properties of fabricated AgNPs, suggesting that phyto-synthesized silver nanoparticles could possess potent anti-pathogenic bacteria and anti-colon cancer activities.

Anti-colon cancer activity of Murraya koenigii leaves is due to constituent murrayazoline and O-methylmurrayamine A induced mTOR/AKT downregulation and mitochondrial apoptosis

In recent years, many alkaloids of plant origin have attracted great attention due to their diverse range of biological properties including anti-hyperglycemic, anti-oxidant, anti-inflammatory, anti-diabetic and anti-tumor activity. Herein, the pyranocarbazole alkaloids were isolated from leaves of Murraya koenigii and their anti-cancer potential was investigated in different cancer cell lines. Among all tested compounds, murrayazoline and O-methylmurrayamine A demonstrated potent anti-cancer activity against DLD-1 colon cancer cells with the IC50 values of 5.7μM and 17.9μM, respectively, without any non-specific cytotoxicity against non-cancer HEK-293 and HaCaT cells. Further, studies of pure compounds revealed that the anti-cancer activity of compounds corresponds with altered cellular morphology, cell cycle arrest in G2/M phase, reactive oxygen species level and mitochondrial membrane depolarization of colon cancer cells. In addition, these compounds activated caspase-3 protein and upregulated Bax/Bcl-2 protein expression ratio leading to induction of caspase-dependent apoptosis in DLD-1 cells. These event induced by carbazole alkaloids also coincides with downregulation of Akt/mTOR suggesting downstream targeting of cell survival pathway. Thus, our in vitro studies not only provided scientific basis of the use of M. koenigii leaves in the traditional Indian Ayurveda medicines, but also expands possibilities of medicinal uses of M. koenigii leaves against colon cancer. Particularly, these findings will help in further investigating murrayazoline and O-methylmurrayamine A or their improvised derivatives as new therapeutics for the treatment of colon cancer.

Abstract 3227: Novel Marmelin analog DBQ targets Notch signaling pathway in colon cancer stem cells

Abstract Background: Colon cancer is the second leading cause of death in the United States. Previously, we have reported that the identification of a novel compound Marmelin from Aegle marmelos and potent anti-colon cancer activity. We have developed novel Marmelin analogue THB from this structure showed potent anti-cancer activity and its inhibitory constant value was 10 µM. From this, we developed a second series of analogs, of which DBQ is even more potent than THB. The current study is designed to determine whether DBQ affects colon cancer stem cells and identify a mechanism. Method: Colon cancer cell lines HCT116 and SW480 and normal colon epithelial cells were used in the study. Cell growth was measured by hexoseaminidase and clonogenicity assays. Apoptosis was determined by measuring caspase 3/7 activities. Colosphere formation assay and FACS sorting were used for stem cells. For in vivo effects, we performed studies in HCT116 tumor xenografts. Immunohistochemistry was determined for stem cell markers and Notch signaling proteins. Results: DBQ treatment induced significant dose-dependent inhibition of proliferation and colony formation of HCT116 and SW480 cells, but not that of the normal FHC colon epithelial cells. DBQ also significantly reduced the number and size of colospheres, suggesting effects on stem cells. In addition, DBQ reduced the levels of colon stem cell marker proteins DCLK1, LGR5, and CD44. We obtained further confirmation by flow cytometry, where DBQ treatment reduced the number of DCLK1+ cells. We next determined whether DBQ affects the Notch signaling, a pathway that is important in maintaining CSC population. Notch receptor and its ligands are up-regulated in human colon cancer tissues. DBQ treatment significantly downregulated the expression of all four Notch isoforms, its ligands Jagged 1, 2 and DLL1, 3, 4 and downstream target protein Hes1. Notch activation requires cleavage by the γ-secretase complex. DBQ treatment inhibits the expression of γ-secretase complex proteins. To confirm that DBQ effect is thorough downregulating Notch activation, we ectopically expressed the Notch Intracellular domain. DBQ effect was significantly mitigated in this condition. To determine the effect of DBQ on tumor growth in vivo, we administered DBQ intraperitoneally (5mg/kg bw) every day for 21 days in mice carrying HCT116 tumor xenografts. DBQ treatment significantly suppressed tumor xenograft growth, with notably lower tumor volume and weight. Western blot and immunohistochemistry analyses demonstrated significant inhibition of CSC marker proteins DCLK1, LGR5 and CD44 and also the Notch signaling proteins in the DBQ-treated xenograft tissues. Conclusion: Together, these data suggest that DBQ treatment suppresses colon cancer growth that targets stem cells in part by inhibiting Notch signaling pathway. Citation Format: Dharmalingam Subramaniam, Sivapriya Ponnurangam, Prasad R. Dandawate, Gaurav Kaushik, Ossama W. Tawfik, Roy A. Jensen, Santimukul Santra, Subhash B. Padhye, Scott J. Weir, Shrikant Anant. Novel Marmelin analog DBQ targets Notch signaling pathway in colon cancer stem cells [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 3227. doi:10.1158/1538-7445.AM2017-3227

Partially Purified Gloriosa superba Peptides Inhibit Colon Cancer Cell Viability by Inducing Apoptosis Through p53 Upregulation

BackgroundColon cancer is a major health problem worldwide. Available treatments such as surgery, chemotherapy, radiation and anticancer drugs are limited due to stage of cancer, side effects and altered biodistribution. The use of peptides extracted from natural products has appeared as a potential therapy. Gloriosa superba is known to contain colchicine and other alkaloids with anticancer activity. However, these peptides contained within the extracts have not been studied. This study, therefore, focuses on an investigation of anti–colon cancer activity from a partially purified protein hydrolysate of G superba rhizome. MethodsDried G superba rhizome was extracted using 0.5% sodium dodecyl sulfate and digested with pepsin. The protein hydrolysates with molecular weight lesser than 3kDa were collected and subjected for cell viability assay. Then, the partial purification of the protein hydrolysate was performed using reverse-phase high-performance liquid chromatography. Fractions containing anticancer peptides were investigated, and their effects on apoptosis and protein expression using apoptosis test and Western blot, respectively. ResultsPartially purified peptides of G superba rhizome demonstrated anticolon activity in SW620 cells by inducing apoptosis through upregulation of p53 and downregulation of nuclear factor kappa B (NF-κB). ConclusionsConsequently, G superba peptides showed high potential for further purification and development of anticolon therapeutics.

Bioassay-guided isolation of glycoprotein SPG-56 from sweet potato Zhongshu-1 and its anti-colon cancer activity in vitro and in vivo

This study is aimed at separating and identifying a new glycoprotein from sweet potato (SPG) and detecting its anti-colon cancer bioactivity. The SPG-56 was obtained by water extraction, isoelectric precipitation, chromatography and electrophoresis. The compositions of sugar and protein in SPG-56 were identified with high performance liquid chromatography and amino acid analyzer, and the antitumor activities were explored using BALB/c nude mice and human colon cancer cells (HCT-116). Results showed that the molecular weight of SPG-56 is 56 KD. Relative sugar and protein contents of SPG-56 are 2.9% and 97.1%, comprising more than 6 types of sugars and 15 kinds of amino acids. Animal experiments showed that orally administrated SPG-56 could obviously suppress the tumor growth. Results from flow cytometry, western blotting and immunohistochemistry indicated that SPG-56 inhibits cancer by inducing apoptosis. These results suggest that SPG-56 would potentially delay the development of colon cancer.

Abstract 4748: Targeting colon cancer stem cells: Novel marmelin analog THB suppresses DCLK1 and Notch Signaling

Abstract Background: Despite therapeutic advances, colon cancer remains the second leading cause of death in the United States. Previously, we have reported that the identification of a novel compound, HDNC or Marmelin from Aegle marmelos with potent anti-colon cancer activity. We have now developed a novel marmelin analogue THB and made it water soluble THB using β-cyclodextrin (THBCD). The current study is designed to determine whether THB affects stem cells and to identify a mechanism. Method: Colon cancer cell lines HCT116 and SW480 and normal colon epithelial cells were used in the study. Cell growth was measured by hexoseaminidase and clonogenicity assays. Apoptosis was determined by measuring caspase 3/7 activities. Colosphere formation assay and FACS sorting were used for stem cells. For in vivo effects, we have performed HCT116 cells induced tumor xenografts. Immunohistochemistry was determined for stem cell markers and Notch signaling proteins. Results: THB treatment induced a significant dose-dependent inhibition of proliferation and colony formation of the two colon cancer cell lines, but not that of the normal cells. To demonstrate THB effects on stem cells, we performed colosphere assays. THB treatment significantly reduced the number and size of colospheres, suggesting effects on stem cells. In addition, colon stem cell marker proteins DCLK1, LGR5, and CD44 were also decreased. Further proof was obtained by flow cytometry analyses, where THB reduced the number of DCLK1+ cells. We next determined whether THB affects the Notch signaling pathway, a pathway that is important in maintaining CSC population. Notch receptor and its ligands are up-regulated in human colon cancer tissues. THB treatment significantly downregulated the expression of Notch1, its ligand Jagged1 and downstream target protein Hes1. Notch activation requires cleavage by the γ-secretase complex. THB treatment inhibits the expression of γ-secretase complex proteins Presenilin1, Nicastrin, APH1 and PEN2. Moreover, ectopic expression of the Notch Intracellular domain (NICD) rescued the cells from THB mediated growth suppression. These data demonstrate that THB mediated effects of colon cancer stem cells is in part through downregulating Notch1 activation. To determine the effect of THB on tumor growth in vivo, mice carrying HCT116 tumor xenografts were administered the compound intraperitoneally (5mg/kg bw) every day for 21 days. THB treatment significantly suppressed tumor xenograft growth, with notably lower tumor volume and weight. Western blot and immunohistochemistry analyses demonstrated significant inhibition of CSC marker proteins DCLK1, LGR5 and CD44 and also the Notch signaling proteins in the THB-treated xenograft tissues. Conclusion: Together, these data suggest that THB treatment suppresses colon cancer growth that targets stem cells by inhibiting Notch1 signaling pathway. Citation Format: Dharmalingam Subramaniam, Sivapriya Ponnurangam, Prasad R. Dandawate, Ossama W. Tawfik, Roy A. Jensen, Scott J. Weir, Subhash B. Padhye, Shrikant Anant. Targeting colon cancer stem cells: Novel marmelin analog THB suppresses DCLK1 and Notch Signaling. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4748.

Dual Drug Loaded Biodegradable Nanofibrous Microsphere for Improving Anti-Colon Cancer Activity.

One of the approaches being explored to increase antitumor activity of chemotherapeutics is to inject drug-loaded microspheres locally to specific anatomic sites, providing for a slow, long term release of a chemotherapeutic while minimizing systemic exposure. However, the used clinically drug carriers available at present have limitations, such as their low stability, renal clearance and residual surfactant. Here, we report docetaxel (DOC) and curcumin (CUR) loaded nanofibrous microspheres (DOC + CUR/nanofibrous microspheres), self-assembled from biodegradable PLA-PEO-PPO-PEO-PLA polymers as an injectable drug carrier without adding surfactant during the emulsification process. The obtained nanofibrous microspheres are composed entirely of nanofibers and have an open hole on the shell without the assistance of a template. It was shown that these DOC + CUR/nanofibrous microspheres could release curcumin and docetaxel slowly in vitro. The slow, sustained release of curcumin and docetaxel in vivo may help maintain local concentrations of active drug. The mechanism by which DOC + CUR/nanofibrous microspheres inhibit colorectal peritoneal carcinomatosis might involve increased induction of apoptosis in tumor cells and inhibition of tumor angiogenesis. In vitro and in vivo evaluations demonstrated efficacious synergistic antitumor effects against CT26 of curcumin and docetaxel combined nanofibrous microspheres. In conclusion, the dual drug loaded nanofibrous microspheres were considered potentially useful for treating abdominal metastases of colorectal cancer.

In Silico Drug-Designing Studies on Flavanoids as Anticolon Cancer Agents: Pharmacophore Mapping, Molecular Docking, and Monte Carlo Method-Based QSAR Modeling.

In silico molecular modeling studies were carried out on some newly synthesized flavanoid analogues. Search for potential targets for these compounds was performed using pharmacophore-mapping algorithm employing inverse screening of some representative compounds to a large set of pharmacophore models constructed from human target proteins. Further, molecular docking studies were carried out to assess binding affinity of these compounds to proteins mediating tumor growth. In vitro anticancer studies were carried out on colon cancer cell lines (HCT116) to assess validity of this approach for target identification of the new compounds. Further important structural features of compounds for anticolon cancer activity were assessed using Monte Carlo-based SMILES and hydrogen graph-Based QSAR studies. In conclusion this study have depicted successful and stepwise application of pharmacophore mapping, molecular docking, and QSAR studies in target identification and lead optimization of flavonoids.

Autophagy inhibition sensitizes WYE-354-induced anti-colon cancer activity in vitro and in vivo.

Mammalian target of rapamycin (mTOR) complex 1 (mTORC1) and mTORC2 are frequently dysregulated in human colon cancers. In the present study, we evaluated the potential anti-colon cancer cell activity by a novel mTORC1/2 dual inhibitor WYE-354. We showed that WYE-354 was anti-survival and anti-proliferative when adding to primary (patient-derived) and established (HCT-116, HT-29, Caco-2, LoVo, and DLD-1 lines) colon cancer cells. In addition, WYE-354 treatment activated caspase-dependent apoptosis in the colon cancer cells. Mechanistically, WYE-354 blocked mTORC1 and mTORC2 activation. Meanwhile, it also induced autophagy activation in the colon cancer cells. Autophagy inhibitors (bafilomycin A1 and 3-methyladenine), or shRNA-mediated knockdown of autophagy elements (Beclin-1 and ATG-5), remarkably sensitized WYE-354-mediated anti-colon cancer cell activity in vitro. Further studies showed that WYE-354 administration inhibited HT-29 xenograft growth in severe combined immunodeficient (SCID) mice. Importantly, its activity in vivo was further potentiated with co-administration of the autophagy inhibitor 3-MA. Phosphorylations of Akt (Ser-473) and S6 were also decreased in WYE-354-treated HT-29 xenografts. Together, these pre-clinical results demonstrate the potent anti-colon cancer cell activity by WYE-354, and its activity may be further augmented with autophagy inhibition.

Miltirone induced mitochondrial dysfunction and ROS-dependent apoptosis in colon cancer cells

AimsTo study the characteristics of miltirone-induced anti-colon cancer effects. Materials and methodsCell viability was detected using MTT assay. LDH (lactate dehydrogenase) leakage was detected using CytoTox96® non-radioactive cytotoxicity kit. Apoptosis was detected by FCM (flow cytometry). Caspase activation was determined by chemiluminescence or western blotting. AIF (apoptosis-inducing factor) expression in the cell fraction was determined by western blotting. ROS (reactive oxygen species), MMP (mitochondrial membrane potential) and mitochondrial mass were determined by confocal microscope. Intracellular calcium was detected by both FCM and confocal microscope. To determine the roles of ROS and Ca2+ in the pro-apoptotic activity of miltirone, colon cancer cells were pretreated with kinds of antioxidants, dicoumarol, calpeptin or BAPTA-AM in some cases. Key findingsMiltirone exhibited potent cytotoxicity on colon cancer cells with a better selectivity than that of dihydrotanshinone. The pro-apoptotic activity of miltirone was p53- and ROS-dependent. In detail, miltirone induced direct mitochondrial damage, including significant decrease of mitochondrial ROS, MMP, mass and increase of intracellular ROS and Ca2+. NQO1 (quinone oxidoreductase1) was supposed to be a defender for the cytotoxicity induced by miltirone in colon cancer cells. Furthermore, miltirone induced time- and concentration-dependent translocation of AIF and activation of caspases. SignificanceIn this study, ROS- and p53-dependent apoptosis induced by miltirone on colon cancer cells was firstly revealed. Strong positive feedback between mitochondrial dysfunction and accumulation of intracellular Ca2+ was suggested to be the characteristic of the anti-colon cancer activity of miltirone.

Quercetin Suppresses the Migration and Invasion in Human Colon Cancer Caco-2 Cells Through Regulating Toll-like Receptor 4/Nuclear Factor-kappa B Pathway.

Objective:The migration and invasion features, which were associated with inflammatory response, acted as vital roles in the development of colon cancer. Quercetin, a bioflavonoid compound, was widely spread in vegetables and fruits. Although quercetin exerts antioxidant and anticancer activities, the molecular signaling pathways in human colon cancer cells remain unclear. Hence, the present study was conducted to investigate the suppression of quercetin on migratory and invasive activity of colon cancer and the underlying mechanism.Materials and Methods:The effect of quercetin on cell viability, migration, and invasion of Caco-2 cells was analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, wound-healing assay, and transwell chambers assay, respectively. The protein expressions of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB) p65, mitochondrial membrane potential-2 (MMP-2), and MMP-9 were detected by Western blot assay. The inflammatory factors, such as tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (Cox-2), and interleukin-6 (IL-6), in cell supernatant were detected by enzyme-linked immunosorbent assay.Results:The concentration of quercetin <20 μM was chosen for further experiments. Quercetin (5 μM) could remarkably suppress the migratory and invasive capacity of Caco-2 cells. The expressions of metastasis-related proteins of MMP-2, MMP-9 were decreased, whereas the expression of E-cadherin protein was increased by quercetin in a dose-dependent manner. Interestingly, the anti-TLR4 (2 μg) antibody or pyrrolidine dithiocarbamate (PDTC; 1 μM) could affect the inhibition of quercetin on cell migration and invasion, as well as the protein expressions of MMP-2, MMP-9, E-cadherin, TLR4, and NF-κB p65. In addition, quercetin could reduce the inflammation factors production of TNF-α, Cox-2, and IL-6.Conclusion:The findings suggested for the 1st time that quercetin might exert its anticolon cancer activity via the TLR4- and/or NF-κB-mediated signaling pathway.SUMMARY Quercetin could remarkably suppress the migratory and invasive capacity of Caco-2 cellsThe expressions of metastasis-related proteins of mitochondrial membrane potential-2 (MMP-2), MMP-9 were decreased, whereas the expression of E-cadherin protein was increased by quercetin in a dose-dependent mannerThe anti-toll-like receptor 4 (TLR4) antibody or pyrrolidine dithiocarbamate affected the inhibition of quercetin on cell migration and invasion, as well as the protein expressions of MMP-2, MMP-9, E-cadherin, TLR4, and nuclear factor-kappa B p65Quercetin could reduce the inflammation factors production of tumor necrosis factors-α, cyclooxygenase-2, and interleukin-6. Abbreviations used: MTT: 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphen yltetrazolium bromide, TLR4: Toll-like receptor 4, NF-κB: Nuclear factor-kappa B, MMP-2: Mitochondrial membrane potential-2, MMP-9: Mitochondrial membrane potential-9, TNF-α: Tumor necrosis factor-α, Cox-2: Cyclooxygenase-2, IL-6: Interleukin-6, ELISA: Enzyme-linked immunosorbent assay, PDTC: Pyrrolidine dithiocarbamate, ROS: Reactive oxygen species, DMSO: Dimethyl sulfoxide, FBS: Fetal bovine serum, DMEM: Dulbecco modified Eagle medium, OD: Optical density, IPP: Image Pro-plus, PBS: Phosphate buffered saline, SD: Standard deviation, ANOVA: One-way analysis of variance, SPSS: Statistical Package for the Social Sciences, ECM: Extracellular matrix, TLRs: Toll-like receptors, LPS: Lipopolysaccharide.

Anti-colon cancer and antioxidant activities of bovine skim milk fermented by selected Lactobacillus helveticus strains

Bioactive compounds released during milk fermentation by proteolytic cleavage of milk proteins have a role beyond their nutritional importance. This study assessed the proteolytic activity of Lactobacillus helveticus strains ASCC953, ASCC474, ASCC1188, and ASCC1315 and their ability to release bioactive compounds capable of exerting antioxidative and in vitro anticarcinogenic properties during incubation at 37°C in reconstituted skim milk. The performance of these strains was not affected by the pH decline during fermentation. Soluble extracts of fermented milk by L. helveticus 474 showed the highest free radical (1,1-diphenyl-2-picrylhydrazyl) scavenging activity at 12 h of fermentation, followed by a significant reduction of this activity at 24 h compared with the other strains and control (untreated milk). Skim milk fermented by L. helveticus strains contained compounds with anti-colon cancer activity at varied levels during fermentation. The activity (19.03–50.98% growth inhibition) was greatest in the extract obtained after 12 h of fermentation, which markedly declined (5.4–9.94%) at the end of fermentation. Lactobacillus helveticus 1315 released compounds into the skim milk supernatant with a greater growth inhibition (50.98%) on colon cancer HT-29 cell line than the other strains. More importantly, these compounds had no significant inhibition effect on normal, primary colon cells T4056. Whereas these results suggest that milk fermented by L. helveticus strains may release bioactive compounds with important multifunctional properties, the characteristics and activities of these compounds appear highly strain- and fermentation time-dependent.

Dihydrotanshinone I induced apoptosis and autophagy through caspase dependent pathway in colon cancer

BackgroundDihydrotanshinone I (DHTS) was previously reported to exhibit the most potent anti-cancer activity among several tanshinones in colon cancer cells. Its cytotoxic action was reactive oxygen species (ROS) dependent but p53 independent. PurposeTo further study the anti-cancer activity of DHTS and its molecular mechanisms of action in colon cancer both in vitro and in vivo. MethodsCaspase activity was detected by fluorescence assay. Apoptosis was detected by flow cytometry and TUNEL assay. Protein levels were analyzed by western blotting. Knockdown of target gene was achieved by siRNA transfection. Formation of LC3B puncta and activation of caspase-3 were detected by confocal fluorescence microscope. In vivo anti-colon cancer activity of DHTS was observed in xenograft tumors in NOD/SCID mice. ResultsAnti-colon cancer activity of DHTS by inducing apoptosis and autophagy was observed both in vitro and in vivo. Mitochondria mediated caspase dependent pathway was essential in DHTS-induced cytotoxicity. The apoptosis induced by DHTS was suppressed by knockdown of apoptosis inducing factor (AIF), inhibition of caspase-3/9 but was increased after knockdown of caspase-2. Meantime, knockdown of caspase-2, pretreatment with Z-VAD-fmk or NAC (N-Acety-L-Cysteine) efficiently inhibited the autophagy induced by DHTS. A crosstalk between cytochrome c and AIF was also reported. ConclusionDHTS-induced caspase and ROS dependent apoptosis and autophagy were mediated by mitochondria in colon cancer. DHTS could be a promising leading compound for the development of anti-tumor agent or be developed as an adjuvant drug for colon cancer therapy.

Response Surface Methodology to Optimize the Preparation of Chitosan/Alginate Nanoparticles Containing Curcumin Diethyl Disuccinate

Curcumin diethyl disuccinate (CDD) is a succinate prodrug of curcumin that hasbetter anti-colon cancer and antinociceptive activities than curcumin and improved stability in phosphate buffer at pH 7.4. However, formulation of CDD for pharmaceutical use is limited. Therefore, this study focused on preparation of chitosan/alginate nanoparticles containing CDD and optimization of the formulation using response surface methodology. Chitosan/alginate nanoparticles were prepared by o/w emulsification and ionotropic gelification. The optimized formulation of nanoparticles containing CDD had achitosan/alginate mass ratio of 0.05:1, a CDD concentration of 3 mg/ml, and a Tween 80®content of 4.05% (w/v). Response surface methodology was found to bean effective technique for optimization of the preparation of chitosan/alginatenanoparticles using a limited number of experiments.

Diarylheptanoids from lesser galangal suppress human colon cancer cell growth through modulating Wnt/β-catenin pathway

The Wnt/β-catenin pathway plays a central role in cell growth and differentiation but abnormal activation causes colorectal carcinogenesis. Inhibiting the Wnt/β-catenin pathway can be a good strategy for chemoprevention and treatment of colorectal cancer. While screening for Wnt/β-catenin pathway inhibitors from food materials, we found that (E)-7-(4-hydroxy-3-methoxyphenyl)-1-phenylhept-4-en-3-one (compound 1), among six diarylheptanoids from lesser galangal (Alpinia officinarum), most potently suppressed Wnt3a-induced β-catenin/T-cell factor activity. Moreover, compound 1 suppressed proliferation of colon cancer cells by inhibiting β-catenin translocation to the nucleus by disrupting the β-catenin/galectin-3 complex. Furthermore, a structure–activity realtionship study implicated that the enone group in the linker is critical and the hydroxy substituent on the aromatic ring is generally preferred for activity. Our findings suggest that diarylheptanoid from lesser galangal exerts anti-colon cancer activity by down regulating the Wnt/β-catenin pathway. Bioactive diarylheptanoids and the basic understanding of their structure–activity relationship could be utilized to develop potential candidates for β-catenin-targeted cancer treatment.

Enhancing the anti-colon cancer activity of quercetin by self-assembled micelles.

Colorectal cancer, a type of malignant neoplasm originating from the epithelial cells lining the colon and/or rectum, has been the third most frequent malignancy and one of the leading causes of cancer-related deaths in the US. As a bioflavonoid with high anticancer potential, quercetin (Qu) has been proved to have a prospective applicability in chemotherapy for a series of cancers. However, quercetin is a hydrophobic drug, the poor hydrophilicity of which hinders its clinical usage in cancer therapy. Therefore, a strategy to improve the solubility of quercetin in water and/or enhance the bioavailability is desired. Encapsulating the poorly water-soluble, hydrophobic agents into polymer micelles could facilitate the dissolution of drugs in water. In our study, nanotechnology was employed, and quercetin was encapsulated into the biodegradable nanosized amphiphilic block copolymers of monomethoxy poly(ethylene glycol)–poly(ε-caprolactone) (MPEG–PCL), attempting to present positive evidences that this drug delivery system of polymeric micelles is effective. The quercetin-loaded MPEG–PCL nanomicelles (Qu-M), with a high drug loading of 6.85% and a minor particle size of 34.8 nm, completely dispersed in the water and released quercetin in a prolonged period in vitro and in vivo. At the same time, compared with free quercetin, Qu-M exhibited improved apoptosis induction and cell growth inhibition effects in CT26 cells in vitro. Moreover, the mice subcutaneous CT26 colon cancer model was established to evaluate the therapy efficiency of Qu-M in detail, in which enhanced anti-colon cancer effect was proved in vivo: Qu-M were more efficacious in repressing the growth of colon tumor than free quercetin. In addition, better effects of Qu-M on inducing cell apoptosis, inhibiting tumor angiogenesis, and restraining cell proliferation were observed by immunofluorescence analysis. Our study indicated that Qu-M were a novel nanoagent of quercetin with an enhanced antitumor activity, which could serve as a promising potential candidate for colon cancer chemotherapy.

Comparison of Antioxidant and Anti-colon Cancer Activities of Red Cabbage (Brassica oleracea) by Microwave Cooking

Abstract The present study was performed to investigate antioxidant and anti-colon cancer activities of red cabbage (Brassica oleracea L. var. capitata f. rubra DC) according to the cooking conditions (raw, microwave, blanching and steaming). The contents of red cabbage extracts were determined as follow: total phenolic contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethy lbenzo -thiazoline-6-sulfonic acid) (ABTS), 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, western blot ana lysis. The total contents of polyphenol and flavonoid of red cabbage were 20.27 mg GAE/g Dry weight ±0.03 and 2.55±0.02 mg RE/g Dry weight. In this study, the total contents of polyphenol were decreased to both microwave and steam cooking. Total antioxidant activity and growth inhibition of HCT116 human colon cancer cells were in the order of raw > microwaving > steaming cooking methods. The se results indicate that red cabbage extracts might have antioxidant and anti-proliferative activity according to the cooking cond itions.Key words: red cabbage, microwave cooking, antioxidant, anti-proliferative, HCT116 colon cancer cells

Characterization of a novel polysaccharide with anti-colon cancer activity from Lactobacillus helveticus MB2-1

The present study aimed at investigating the potential anti-colon cancer activity of three purified exopolysaccharides fractions (LHEPS-1, LHEPS-2 and LHEPS-3) from the Lactobacillus helveticus MB2-1. The experimental evidence showed that LHEPS-1 significantly inhibited cell proliferation of human colon cancer Caco-2 cells in both time- and concentration-dependent manners. In contrast, no significant improvements of the inhibitory effects of LHEPS-2 and LHEPS-3 on Caco-2 cells were observed with increasing sample concentrations or prolonged incubation time. Furthermore, the structure of LHEPS-1 was elucidated using methylated analysis, gas chromatography–mass spectroscopy (GC–MS) and nuclear magnetic resonance spectroscopy (NMR), including one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR). Results indicated that the LHEPS-1 consisted of a decasaccharide repeating unit with the following structure (n≈122)：Our results suggested that the LHEPS-1 produced by L. helveticus MB2-1 might be suitable for using as natural anti-colon cancer drugs and functional foods ingredients.

Water stress proteins from Nostoc commune Vauch. exhibit anti-colon cancer activities in vitro and in vivo.

Nostoc commune has been traditionally used in China as a health food and medicine. The water stress proteins (WSP) of Nostoc commune are the major component of the extracellular matrix. This study purified and identified the water stress proteins (WSP1) from Nostoc commune Vauch., which could inhibit the proliferation of human colon cancer cell lines. The IC50 values of WSP1 against DLD1, HCT116, HT29, and SW480 cells were 0.19 ± 0.02, 0.21 ± 0.03, 0.39 ± 0.05, and 0.41 ± 0.01 μg/μL, respectively. Notably, it displayed very little effect on the normal human intestinal epithelial FHC cell line. The IC50 value of WSP1 against FHC cells was 0.67 ± 0.05 μg/μL. Moreover, the growth of DLD1 xenografted tumors in nude mice were significantly suppressed in the WSP1 treated group. Mechanistically, the cell-cycle analysis revealed that WSP1 induced growth inhibition by G1/S arrest. Meanwhile, Western blotting and immunohistochemistry assays showed WSP1 could activate caspase-8, -9, and -3, along with subsequent PARP cleavage. Furthermore, the pan-caspase inhibitor, z-VAD-FMK, partly reversed the effect caused by WSP1, confirming that WSP1 induced cell apoptosis through caspase-dependent pathway. Collectively, WSP1 has targeted inhibition for colon cancer proliferation both in vitro and in vivo and it is valuable for future exploitation and utilization as an antitumor agent.