β-eudesmol,a sesquiterpene from Teucrium ramosissimum,inhibits superoxide production,proliferation, adhesion and migration of human tumor cell

Reactive oxygen species are well-known mediators of various biological responses. Recently, new homologues of the catalytic subunit of NADPH oxidase have been discovered in non phagocytic cells. These new homologues (Nox1–Nox5) produce low levels of superoxides compared to the phagocytic homologue Nox2/gp91phox. In this study we examined the effect of β-eudesmol, a sesquiterpenoid alcohol isolated from Teucrium ramosissimum leaves, on proliferation, superoxide anion production, adhesion and migration of human lung (A549) and colon (HT29 and Caco-2) cancer cell lines. Proliferation of tumor cells was inhibited by β-eudesmol. It also significantly inhibited superoxide production in A549 cells. Furthermore, β-eudesmol inhibited adhesion and migration of A549 and HT29 cell. These results demonstrate that β-eudesmol may be a novel anticancer agent for the treatment of lung and colon cancer by different ways: by inhibition of superoxide production or by blocking proliferation, adhesion and migration.     

Acetyl-keto-beta-boswellic acid inhibits cellular proliferation through a p21-dependent pathway in colon cancer cells

1. Although there is increasing evidence showing that boswellic acid might be a potential anticancer agent, the mechanisms involved in its action are unclear. 2. In the present study, we showed that acetyl-keto-beta-boswellic acid (AKBA) inhibited cellular growth in several colon cancer cell lines. Cell cycle analysis by flow cytometry showed that cells were arrested at the G1 phase after AKBA treatment. 3. Further analysis showed that cyclin D1 and E, CDK 2 and 4 and phosphorylated Rb were decreased in AKBA-treated cells while p21 expression was increased. 4. The growth inhibitory effect of AKBA was dependent on p21 but not p53. HCT-116 p53(-/-) cells were sensitized to the apoptotic effect of AKBA, suggesting that p21 may have protected cells against apoptosis by inducing a G1 arrest.5. In conclusion, we have demonstrated that AKBA inhibited cellular growth in colon cancer cells. These findings may have implications to the use of boswellic acids as potential anticancer agents in colon cancer.     

Plumbagin induces apoptosis,cell cycle arrest,and inhibits protein synthesis in LoVo colon cancer cells: A proteomic analysis

Extracted from the roots of Plumbago zeylanica L., plumbagin is a natural naphthoquinone with potential as an anticancer compound. However, no studies have investigated its impact on LoVo (colon cancer) cells, and the specific mechanisms by which plumbagin exerts its anticancer effects remain to be established. The anticancer potential of plumbagin against LoVo cells was evaluated using a battery of assays, including MTT assay, clone formation assay, transwell chamber invasion assay, and wound-curing assay. Cell cycle analysis and cell apoptosis analysis were conducted to break down the anticancer impact of plumbagin on LoVo cells. A label-free proteomics technology was employed to investigate alterations in protein expression in LoVo cells treated with plumbagin. Our investigation indicated that plumbagin markedly inhibited the LoVo cells proliferation, and induced the apoptosis in LoVo cells, simultaneously induced G0/G1 phase cell cycle arrest. The LC-MS/MS proteomics assay revealed 78 proteins that were differentially expressed upon treatment with plumbagin. Bioinformatics and functional analyses indicated that these proteins were predominantly involved in protein synthesis and translation. Our findings revealed that multiple mechanisms are involved in the anticancer activity of plumbagin against LoVo cells, resulting in decreased cell viability. Proteomic analysis suggests that plumbagin may impede protein synthesis by reducing the expression of eukaryotic initiation factors. Our findings demonstrate that plumbagin exerts its anticancer activity against LoVo cells through multiple mechanisms, including inhibition of cell proliferation, induction of apoptosis, cell cycle arrest, and disruption of protein synthesis. These results provide new insights into the therapeutic potential of plumbagin for colon cancer treatment.     

Design, synthesis, and biological testing of 4beta-[(4-substituted)-1,2,3-triazol-1-yl]podophyllotoxin analogues as antitumor agents

A series of 4beta-[(4-substituted)-1,2,3-triazol-1-yl]podophyllotoxin analogues have been synthesized with high regio-selectivity by employing copper(I)-catalyzed 1,3-dipolar cycloaddition of 1-O-propargyl monosaccharides with C4beta-azido podophyllotoxin and C4beta-azido-4'-O-demethyl podophyllotoxin. All the compounds were evaluated for their anticancer activity against a panel of six human cancer cell lines. Among these, 4'-O-demethyl podophyllotoxin congeners are showing promising anticancer activity mainly against HCT-15 (colon) and DU-145 (prostate) cells.     

Development and characterization of a model of liver metastasis using human colon cancer HCT-116 cells

In order to develop a model of liver metastasis of human gastrointestinal cancer cells, we examined the potential of 10 human colon and stomach cancer cell lines (HT-29, WiDr, HCT-116, HCT-15, HCC-2998, MKN7, MKN28, MKN45, MKN74 and St-4) to form liver metastases in nude mice. Among the cell lines, HCT-116 cells consistently formed gross liver metastases when injected into the spleens of nude mice. In contrast, other human colon and stomach cancer cells produced little or no liver metastasis. In order to analyze the high metastatic potential of HCT-116 cells, the adhesion potential was compared between HCT-116 cells and the other colon cancer cell lines. HCT-116 cells showed more efficient adhesion to fibronectin (FN) than other cells. Furthermore, FN enhanced haptotaxis of HCT-116 cells, but not of other colon cancer cells. The high adhesion potential to FN and enhanced haptotaxis may contribute, at least in part, to the high metastatic potential of HCT-116. To assess the value of this newly developed model of liver metastasis, we compared the ability of four anticancer drugs (fluorouracil, doxifluridine, paclitaxel and irinotecan) to inhibit the formation of liver metastases. Paclitaxel and irinotecan showed strong inhibition of liver metastasis but fluorouracil and doxifluridine showed only slight inhibition. Therefore, this model of metastasis may be useful for screening anti-liver metastatic reagents. These results indicate that the HCT-116 liver-metastasis model should be useful for analyzing the molecular mechanism of liver metastasis and for evaluating new anti-liver metastatic drugs.     

Protodioscin (NSC-698 796): its spectrum of cytotoxicity against sixty human cancer cell lines in an anticancer drug screen panel

Protodioscin (NSC-698 796) is a furostanol saponin isolated from the rhizome of Dioscorea collettii var. hypoglauca (Dioscoreaceae), a Chinese herbal remedy for the treatment of cervical carcinoma, carcinoma of urinary bladder and renal tumor for centuries. To systematically evaluate its potential anticancer activity, protodioscin was tested for cytotoxicity in vitro against 60 human cancer cell lines in the NCI's (National Cancer Institute, USA) anticancer drug screen. As a result, protodioscin was cytotoxic against most cell lines from leukemia and solid tumors in the NCI's human cancer panel, especially selectively against one leukemia line (MOLT-4), one NSCLC line (A549/ATCC), two colon cancer lines (HCT-116 and SW-620), one CNS cancer line (SNB-75), one melanoma line (LOX IMVI), and one renal cancer line (786 - 0) with GI50 < or = 2.0 microM. In the general view of mean graphs, leukemia, colon cancer and prostate cancer are the most sensitive subpanels, while ovarian cancer is the least sensitive subpanel. Based on an analysis of COMPARE computer program with protodioscin as a seed compound, no compounds in the NCI's anticancer drug screen database have cytotoxicity patterns (mean graphs) similar to those of protodioscin, indicating that a potential novel mechanism of anticancer action is involved.     

Characterization of the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound,in vitro and in vivo

Aim:

To investigate the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound in vitro and in vivo.

Methods:

The anti-proliferative action of S115 was analyzed in 12 human and mouse cancer cell lines using MTT assay. Autograft and xenograft cancer models were made by subcutaneous inoculation of cancer cells into mice or nude mice. The mice were orally treated with S115 (2, 8, 32 mg·kg⁻¹·d⁻¹) for 7 d, and the tumor size was measured every 3 d. Cell apoptosis and cell cycle distribution were examined using flow cytometry, gene expression profile analyses, Western blots and RT-PCR.

Results:

The IC₅₀ values of S115 against 12 human and mouse cancer cell lines ranged from 0.3 to 6.6 μmol/L. The tumor growth inhibition rate caused by oral administration of S115 (32 mg·kg⁻¹·d⁻¹) were 89.7%, 81.7%, 78.4% and 77.8%, respectively, in mouse model of B16 melanoma, mouse model of Colon26 colon cancer, nude mouse model of A549 lung cancer and nude mouse model of SK-OV-3 ovarian cancer. Furthermore, oral administration of S115 (7.5 mg·kg⁻¹·d⁻¹) synergistically enhanced the anticancer effects of cyclophosphamide, cisplatin, or 5-fluorouracil in mouse model of S180 sarcoma. Treatment of A549 human lung cancer cells with S115 (1.5 μmol/L) induced G₀/G₁ cell cycle arrest, and increased apoptosis. Furthermore, S115 downregulated the level of ubiquitin, and upregulated the level of Tob2 in A549 cells.

Conclusion:

S115 exerts anticancer effects against a variety of cancer cells in vitro and in grafted cancer models by inducing apoptosis, downregulating ubiquitin and upregulating Tob2.     

Synthesis and antitumor activity of 2‐isocamphanyl thiosemicarbazone derivatives via ROS‐enhanced mitochondrial damage

A series of novel 2‐isocamphanyl thiosemicarbazone derivatives were synthesized and characterized by ¹H NMR, ¹³C NMR, and HRMS. In in vitro anticancer activity, most derivatives showed considerable cytotoxic activity against four cancer cell lines (RPMI‐8226, A549, MDA‐MB‐231, and HepG2 cancer cells) and showed low toxicity against human gastric mucosal cells (GES‐1). Among them, compound 4h exhibited excellent antitumor activity against the tested cancer cells with IC₅₀ values of 0.4, 1.1, 1.6, and 1.7 μM for MDA‐MB‐231, RPMI‐8226, A549, and HepG2, respectively. Further, mechanism studies indicated that compound 4h induced apoptosis in MDA‐MB‐231 cells through enhancing reactive oxygen species levels, inducing mitochondrial membrane potential decrease, and influencing the expression of Bax, Bcl‐2, caspase‐3, and caspase‐9.     

Formulation,characterization, and cellular toxicity assessment of tamoxifen-loaded silk fibroin nanoparticles in breast cancer

Silk fibroin (SF) is a natural polymeric biomaterial that is widely adopted for the preparation of drug delivery systems. Herein, we aimed to fabricate and characterize SF nanoparticles loaded with the selective estrogen receptor modulator; tamoxifen citrate (TC-SF-NPs) and to assess their in vitro efficacy against breast cancer cell lines (MCF-7 and MDA-MB-231). TC-loaded SF-NPs were characterized for particle size, morphology, entrapment efficiency, and release profile. In addition, we examined the in vitro cytotoxicity of TC-SF-NPs against human breast cancer cell lines and evaluated the anticancer potential of TC-SF-NPs through apoptosis assay and cell cycle analysis. Drug-loaded SF-NPs showed an average particle size of 186.1 ± 5.9 nm and entrapment efficiency of 79.08%. Scanning electron microscopy (SEM) showed the nanoparticles had a spherical morphology with smooth surface. Tamoxifen release from SF-NPs exhibited a biphasic release profile with an initial burst release within the first 6 h and sustained release for 48 h. TC-SF-NPs exerted a dose-dependent cytotoxic effect against breast cancer cell lines. In addition, flow cytometry analysis revealed that cells accumulate in G₀/G₁ phase, with a concomitant reduction of S- and G₂-M-phase cells upon treatment with TC-SF-NPs. Consequently, the potent anticancer activities of TC-SF-NPs against breast cancer cells were mainly attributed to the induction of apoptosis and cell cycle arrest. Our results indicate that SF nanoparticles may represent an attractive nontoxic nanocarrier for the delivery of anticancer drugs.     

The labdane diterpene sclareol (labd-14-ene-8, 13-diol) induces apoptosis in human tumor cell lines and suppression of tumor growth in vivo via a p53-independent mechanism of action

The labdane diterpene sclareol has demonstrated significant cytotoxicity against human tumor cell lines and human colon cancer xenografts. Therefore, there is need to elucidate the mode of action of this compound as very little information is known for the anticancer activity of sclareol and other labdane diterpenes, in general. COMPARE analysis of GI(50) values for a number of human cancer cell lines was initially implicated in an effort to assign a putative mechanism of action to the compound. Sclareol-induced cell cycle arrest and apoptosis were assessed by flow cytometry and Western blot analyses. Finally, the anticancer ability of sclareol in vivo was assessed by using human colon cancer xenograft/mouse models. Sclareol arrested in vitro the growth of p53-deficient (HCT116(p53-/-)) human colon cancer cells and subsequently induced apoptosis by activating both caspases-8 and -9. Intraperitoneal administration of liposome-encapsulated sclareol at the maximum tolerated dose induced a marked growth suppression of HCT116(p53-/-) tumors established as xenografts in immunodeficient NOD/SCID mice. In conclusion, we demonstrate herein that sclareol kills human tumor cells by inducing arrest at the G(1)-phase of the cell cycle followed by apoptosis that involves activation of caspases-8, -9 and -3 via a p53-independent mechanism. These findings suggest that liposome-encapsulated sclareol possesses chemotherapeutic potential for the treatment of colorectal and other types of human cancer regardless of the p53-status.     

Anti-proliferation activity of total flavonoids isolated from Diospyros kaki L. f. leaves against human cancer celllines

OBJECTIVE To investigate the in vitro anti-proliferation activity of PLF against several human cancer cell lines and revealed its potentials as anticancer agent. METHODS The anti-proliferation activity of PLF against six human cancer cell lines and three normal human cell lines was evaluated by Alarma Blue method.The apoptosis induction of PLF in HCT116 cells was detected using high-content analysis with FITC-Annexin Ⅴ/propidium iodide(PI) double staining. The production of intracellular reactive oxygen species(ROS) induced by PLF was accessed using DHE dye. The ability of PLF to scavenge free radical was investigated by DPPH assay.RESULTS In a concentration of up to 30 mg·L~(-1), PLF showed moderate to high anti-proliferation activity against six different types of human cancer cells, but little cytotoxicity to normal human cells. PLF induced apoptosis and intracellular ROS in HCT116 human colon cancer cells. In addition, PLF showed strong DPPH free radical scavenging ability in the antioxidant assay. CONCLUSION PLF demonstrated significant inhibition against the proliferation of liver, breast, and colon cancer cells in vitro.The anti-proliferation activity of PLF against cancer cells was related to the promotion of oxidative stress and the induction of apoptosis. PLF can be a potential candidate as anticancer drug due to the activities shown in vitro and in vivo and worth further research.     

Synthesis and Evaluation of Flavanones as Anticancer Agents

A few flavanones were synthesised by cyclisation of corresponding 3-(heteroaryl)-1(2-hydroxyphenyl) prop-2-en-1-one with sodium acetate in alcohol–water and evaluated for activity. Synthesised compounds were assayed for their in vitro anticancer activity against three human cancer cell lines, mammary adenocarcinoma (MCF7), human colon adenocarcinoma (HT29) and human kidney adenocarcinoma (A498) using sulforhodamine B dye. Results indicated that most of the compounds exhibited significant in vitro anticancer potential. Among them, compound having furan ring showed most potent activity against all the tested cell lines.     

In vitro and in vivo growth inhibition and G1 arrest in human cancer cell lines by diaminophenyladamantane derivatives

We describe the discovery of a novel series of anticancer adamantane derivatives which induce G1 arrest in Colo 205 and HT 29 colon cancer cells. Seven adamantane derivatives were screened for their activity in vitro against 60 human cancer cell lines in the National Cancer Institute (NCI)'s Anticancer Drug Screen system. The relationships between structure and in vitro anticancer activity are discussed. 1,3-Bis(4-(4-amino-3-hydroxyphenoxy)phenyl)adamantane (1,3-DPA/OH/NH2) and 2,2-bis(4-(4-amino-3-hydroxyphenoxy)phenyl)adamantane (DPA) exhibited strong growth inhibitory on anticancer activities in vitro. The IC50s of 1,3-DPA/OH/NH2 (NSC-706835) and DPA (NSC-706832) were found to be < 3 microM against 45 (85%) and 48 (91%) cell lines, respectively. 2,2-Substituted adamantane derivatives exhibited stronger growth inhibition on anticancer activities in vitro than the corresponding 1,3-substituted analogs. Very strong growth inhibition of 2,2-bis(4-aminophenyl)adamantane (NSC-711117) was observed against two colon cancer lines (HT-29 and KM-12), one CNS cancer line (SF-295) and one breast cancer line (NCI/ADR-RES) with IC50 < 1.0 microM, i.e. 0.1, 0.01, 0.059 and 0.079 microM, respectively. In addition, we also examined the in vitro and in vivo effects of DPA on three human colon cancer cells. DPA-treated Colo 205 and HT-29 cells were arrested at G0/G1 as analyzed by flow cytometric analysis. The DPA-induced cell growth inhibition was irreversible after removal of DPA. The in vivo effect of tumor growth suppression by DPA was also observed on colon Colo 205 xenografts. No acute toxicity was observed after an i.p. challenge of DPA in ICR nude mice weekly. These results suggest that DPA appears to be a new potentially less toxic modality of cancer therapy.     

Cytotoxicity of sphingoid marine compound analogs in mono- and multilayered solid tumor cell cultures

Summary A subset of four synthetic sphingoid marine compound analogs was chosen from a preliminary in vitro cytotoxicity study for further analysis. The selected analogs were initially screened in monolayer cultures for their anticancer potential against a panel of eight human tumor cell lines, ovarian, colon and lung cancer, squamous cell carcinoma and leukemia producing IC₅₀ values ranging from 1.5 to 6.9 μM. In a secondary screening, the sphingoid analogs were evaluated against multilayered postconfluent cultures of A2780 ovarian cancer and WiDr colon cancer cells. In this model, compounds 5 and 8 were the most active derivatives showing EC₅₀ values in the range 25–32 μM. The performance of 5 and 8 against both cell lines was not dependent on the cell culture model as shown with resistance factor values in the range 8–12. Cell cycle studies in HL60 leukemia cells showed an arrest in G ₀/G ₁ at a low drug concentration (3 μM) but accumulation in S phase at a high drug concentration (9 μM). It can be concluded that the analogs showed a cell line independent activity, with an apparent selectivity against cells grown in more physiological three-dimensional condition compared to standard anticancer drugs.     

Valproic acid inhibits prostate cancer cell migration by up-regulating E-cadherin expression

E-Cadherin plays important roles in cell-cell adhesion, epithelial-to-mesenchymal transition, cancer cell migration and invasion. Valproic acid (VPA), a well-known inhibitor of class I and class II histone deacetylases, has been considered a promising anticancer drug due to its capacity of inducing cancer cell proliferation arrest and death through different mechanisms. However, effects of VPA on E-cadherin mediated cell-cell adhesion and cancer cell migration remain unclear. In the present study, we found that VPA potently induced hyperacetylation of histone H3 and H4, increased the expression of E-cadherin and inhibited cell migration in prostate cancer cells. Furthermore, knock-down of E-cadherin significantly restored the effects of VPA on cell migration, while over-expression of E-cadherin in prostate cancer cells significantly inhibited cell migration to a similar level as VPA treatment. These results thus suggest that up-regulation of E-cadherin and inhibition of cell migration may represent a new anticancer mechanism of VPA.     

Synthesis,characterization, and biological studies of diosgenyl analogs

A series of diosgenyl analogs were prepared from diosgenin to evaluate their anticancer activity and antithrombotic property. Analog 4, which had a spiroketal structure with a 6-aminohexanoic acid residue, exhibited the highest potency against all five tumor cell lines. It significantly blocked tumor growth, induced cell apoptosis and autophagy, and regulated cellular calcium concentration, mitochondrial membrane potential, adenosine triphosphate, and cell cycle. In addition, fluorescence-tagged compounds indicated that the analogs could rapidly accumulate in the cytoplasm, but no specific localization in the nucleus of cancer cells was observed. Furthermore, preliminary structure–activity relationship studies demonstrated that spiroketal analogs exhibit better antithrombotic activity than furostanic analogs, which exhibit the opposite effect by promoting thrombosis. Our study indicates that compound 4 may be a promising anticancer drug candidate for cancer patients with thromboembolism.     

Isothiocyanate analogs targeting CD44 receptor as an effective strategy against colon cancer

Inflammatory pathway plays an important role in tumor cell progression of colorectal cancers. Although colon cancer is considered as one of the leading causes of death worldwide, very few drugs are available for its effective treatment. Many studies have examined the effects of specific COX-2 and 5-LOX inhibitors on human colorectal cancer, but the role of isothiocyanates (ITSCs) as COX–LOX dual inhibitors engaged in hyaluronan–CD44 interaction has not been studied. In the present work, we report series of ITSC analogs incorporating bioisosteric thiosemicarbazone moiety. These inhibitors are effective against panel of human colon cancer cell lines including COX-2 positive HCA-7, HT-29 cells lines, and hyaluronan synthase-2 (Has2) enzyme over-expressing transformed intestinal epithelial Apc10.1Has2 cells. Specifically, our findings indicate that HA-CD44v6-mediated COX-2/5-LOX signaling mediate survivin production, which in turn, supports anti-apoptosis and chemo-resistance leading to colon cancer cell survival. The over-expression of CD44v6shRNA as well as ITSC treatment significantly decreases the survival of colon cancer cells. The present results thus offer an opportunity to evolve potent inhibitors of HA synthesis and CD44v6 pathway and thus underscoring the importance of the ITSC analogs as chemopreventive agents for targeting HA/CD44v6 pathway.     

Herbal formula enhances 5-fluorouracil activity through suppression of thymidylate synthase

Traditional Chinese herbal medicine(TCM) has been shown to enhance the efficacy of standard anticancer agents. However, there are only a limited number of well-controlled preclinical and clinical studies documenting the potential benefit of TCM. OBJECTIVE To identify biologically active formulas that were effective against colorectal cancer(CRC)by screening TCM formulas in in vitro and in vivo animal models. METHODS Cell growth assays, cell cycle analysis,immunoblot analysis and q RT-PCR were performed to investigate the mechanism(s) of action of the formulason human CRC cells. In vivo animal models were used to evaluate the antitumor activity of formulasalone and in combination with5-FU. RESULTS We identified Huangqin Gegen Tang(HQGGT) which suppressed the in vivo growth of human CRC HT-29 xenografts. HQGGT significantly inhibited the growth of CRC cell lines. HQGGT enhanced the cytotoxicity of5-FU against human 5-FU-resistant cells(H630 R1) and mouse colon cancer cells(MC38). This synergy was the result of suppression of thymidylate synthase expression by HQGGT. HQGGT significantly enhanced the antitumor effect of5-FU in mice bearing MC38 xenografts. Ongoing studies have identified Huangqin as the herb responsible for TS inhibition. CONCLUSION These findings provide support for the potential role of HQGGT as a novel modulator of fluoropyrimidine chemotherapy for CRC treatment.