N-Benzoyl-12-nitrodehydroabietylamine-7-one, a novel dehydroabietylamine derivative, induces apoptosis and inhibits proliferation in HepG2 cells

Crystal structure, in vitro cytotoxicity, DNA binding and DFT calculations of new copper (II) complexes with coumarin-amide ligand

This work describes the synthesis, anticancer activity and electron structure study of two Cu (II) complexes with coumarin-3-formyl-(3-(aminomethyl) pyridine) ligand (L) - C1 (Cu₂L₂(OAc)₄) and C2 (CuL₂(NO₃)₂). The structure of C1 and C2 was confirmed by elemental analysis, FTIR, and single-crystal X-ray analysis. Complex C1 crystallizes as binuclear where two Cu (II) ions are bridged by four acetate ligands while C2 is a mononuclear complex with twisted octahedral geometry. Density functional theory (DFT) calculations revealed that electronic transitions originate from metal-ligand charge transfer and d-d transitions of metal ions. According to the results of UV-Vis and fluorescence titrations, C1 and C2 intercalate with DNA with the binding constants of 6.9 × 10⁵ M^-1 and 5.9 × 10⁵ M^-1, respectively. The in vitro cytotoxicity assays on four cancer cell lines (HeLa, HepG2, MCF-7 and A549) and a normal HUVEC cell line indicated higher anti-MCF-7 activity of C2 compared with cisplatin (IC₅₀ = 2.86 ± 0.08 μM vs. 9.07 ± 0.10 μM). Moreover, C2 had superior selectivity since IC₅₀ toward HUVEC cells was over 150 μM compared with 0.58 ± 0.05 μM for cisplatin. We concluded that the anti-MCF activity of mononuclear C2 complex is better than that of binuclear C1 and cisplatin. Therefore, C2 has been selected as a hit compound to develop novel non‑platinum anticancer agents through modification of coumarin-amide structure and variation of copper (II) salts.

Cytotoxic Dehydroabietylamine Derived Compounds

BACKGROUND AND METHODS

Chemotherapy remains one of the most important methods for the treatment of cancer. More recently in this context, some products derived from natural products have raised scientific interest which especially include many terpenes. Thereby, diterpenoids represent a special class, and within this class of important secondary natural products, especially compounds derived from Dehydroabietylamine (DA), are of particular interest.

RESULTS

This review not only gives a summary of the most important findings on the cytotoxic behavior of DAderived compounds but also shows some drawbacks of these compounds, such low bioavailability and/or poor solubility of several derivatives of DA. It focusses on the chemical aspects and summarizes the DA related biological effects without deep discussion of underlying biochemical pathways.

CONCLUSION

Dehydroabietylamine-derived cytotoxic compounds hold a high potential to be developed into efficient antitumor active drugs.

Ultrasound-assisted enzymatic extraction of anthocyanins from grape skins: optimization, identification, and antitumor activity

Grape skins produced during the grape juice production and processing contain abundant anthocyanins and other active compounds. Consequently, this study optimized the extraction conditions for ultrasound-assisted enzymatic extraction (UAEE) of anthocyanins from grape skins via response surface methodology coupled with genetic algorithm. The optimum extraction parameters to achieve the highest anthocyanins yield (3.01 ± 0.04) mg/g from grape skins by UAEE were obtained under an extraction temperature of 50 °C, ultrasonic power of 400 W, pectinase dosage of 0.16%, and extraction time of 28 min. The AB-8 macroporous resin combined Sephadex LH-20 techniques were further employed to purify the anthocyanins extracts obtained under optimum extraction conditions (AEOEC), and the main anthocyanins were identified using high-performance liquid chromatography tandem mass spectrometry. The purified anthocyanins contained two anthocyanins in terms of delphinidin-3,5-O-diglucoside and cyanidin-3-O-rutinoside with purity of 91.35% and 92.64%, respectively. Ultimately, we further evaluated the antitumor activity of AEOEC and two purified anthocyanins on breast cancer. The results indicated that the antitumor effect of AEOEC on breast cancer MCF-7 cells was better than that of two purified anthocyanins. In addition, AEOEC could memorably increase intracellular reactive oxygen species levels and apoptosis of MCF-7 cells, and arrest MCF-7 cells in the G2/M phases. The findings provide an effective and feasible method for anthocyanins extraction and reduce the environmental burden of this waste.

Dracorhodin perchlorate protects pancreatic β-cells against glucotoxicity- or lipotoxicity-induced dysfunction and apoptosis in vitro and in vivo

Glucotoxicity or lipotoxicity leads to hyperglycemia and insulin secretion deficiency, which are important causes for the onset of type 2 diabetes mellitus (T2DM). Thus, the restoration of β-cell function is a long-sought goal in diabetes research. Previous studies have implicated pancreatic and duodenal homeobox 1 gene (Pdx1) in β-cell function and insulin secretion. In this study, we established a Pdx1 promoter-dependent luciferase system and identified the natural compound dracorhodin perchlorate (DP) as an effective promotor of Pdx1 expression. We further demonstrated that DP could significantly inhibit β-cell apoptosis induced by 33 mm glucose or 200 μm palmitate by interfering with endoplasmic reticulum stress and mitochondrial pathways and enhance insulin secretion as well. These effects were associated with enhanced activities of Erk1/2, which in turn promoted Pdx1 expression and increased the ratio of Bcl2/Bax, since inhibition of the Erk1/2 pathway abolished the DP-induced expression of Pdx1 and suppression of apoptosis. In addition, our in vivo results in diabetic mice indicated that DP treatment lowered blood glucose, raised insulin levels, enhanced Pdx1 expression and increased islet size and number in the pancreas of diabetic mice. Our findings suggest that Pdx1 is a potential target molecule of DP in the treatment of T2DM via the inhibition of glucotoxicity- or lipotoxicity- induced β-cell apoptosis and the attenuation of insulin secretion dysfunction.

Synthesis and potential antineoplastic activity of dehydroabietylamine imidazole derivatives

To seek more efficient and lower toxicity anticancer compounds, several imidazole combining dehydroabietylamine derivatives including organic salts (L 1 -L 2 ) and amides (L 3 -L 5 ) were synthesized. Their antineoplastic activity against HeLa (cervix), MCF-7 (breast), A549 (lung) and HepG2 (liver) cells and HUVECs (umbilical vein, normal cells) in vitro were evaluated by MTT assay. The results unequivocally showed that nearly all compounds had better antineoplastic activity and lower toxicity than dehydroabietylamine (L 0 ). For MCF-7 cells, L 2 (0.75 μM) and L 5 (2.17 μM) had higher anti-MCF-7 activity than L 0 and DOX. For A549 cells, L 1 (1.85 μM) and L 2 (4.37 μM) had higher anti-A549 activity than L 0 ; in particular, the IC50 value of L 1 was much lower than that of DOX. Among these investigated compounds, L 2 and L 5 had lower IC50 values (0.75 μM and 2.17 μM) against MCF-7 cells and lower toxicity, which suggested that they may be potential future anticancer drugs. In addition, L 1 and L 2 could suppress cancer cell proliferation by inducing apoptosis. L 1 -L 5 could bind with DNA through intercalation.

Syntheses of C-ring modified dehydroabietylamides and their cytotoxic activity

Due to their auspicious pharmacological efficacy as future drug candidates, natural products have been attracting scientific interest for centuries. An interesting field of research concerns the natural product class of terpenes. In this regard, a multitude of studies have already shown their promising biological potential. Therefore, a set of 27 derivatives of the diterpene dehydroabietylamine was synthesized, focusing on C-ring modifications and the derivatization of the amino moiety at C-18. Subsequent screening of the compounds in colorimetric sulforhodamine B-assays revealed an in vitro cytotoxicity especially towards malignant cell line MCF7. Particularly, 12-hydroxy-N-(isonicotinoyl)dehydroabietylamine and N-(4-methoxybenzoyl)dehydroabietylamine showed good cytotoxic activities (EC₅₀ (MCF7) = 4.3 ± 0.2 μM and EC₅₀ (MCF7) = 4.5 ± 1.5 μM, respectively) and significant selectivities (SI = 6.2 and SI = 8.8, respectively) towards malignant cell lines.

High anticancer potency on tumor cells of dehydroabietylamine Schiff-base derivatives and a copper(II) complex

Five bioactive dehydroabietylamine Schiff-base derivatives (L¹-L⁵) had been synthesized from Dehydroabietylamine (L⁰), and the complex Cu(L¹)₂ had been obtained from the compound L¹ and copper(II) acetate. Their activities against Hela (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver) and HUVEC (umbilical vein, normal cell) in vitro were investigated. The toxicity of L¹-L⁵ and Cu(L¹)₂ was all lower than L⁰. For MCF-7 cell, L¹, L³, L⁴, L⁵ and Cu(L¹)₂ had higher antitumor activity than L⁰. The smallest IC₅₀ value was 2.58 μM of L⁵. For A549 cell, the IC₅₀ value of the compound L⁴ was smaller than L⁰, which indicated that the compound L⁴ had higher anti-A549 activity than L⁰. For HepG2 cell, the IC₅₀ value of L⁴(0.24 μM) and L⁵ (0.14 μM) were much smaller than L⁰, which suggested L⁴ and L⁵ had higher anti-HepG2 activity. L⁵ was 180 times more effective at inhibiting cultured HepG2 cells survival than normal cells, with average IC₅₀ values of 0.14 and 25.56 μM. Furthermore, L⁰, L⁴ and L⁵ contrasting with Doxorubicin had been measured with the ability to induce apoptosis. It turned out that L⁴ and L⁵ could induce more HepG2 cells apoptosis, which suggested they may be potential antitumor drugs.

Cancer-selective death of human breast cancer cells by leelamine is mediated by bax and bak activation

The present study is the first to report inhibition of breast cancer cell growth in vitro and in vivo and suppression of self-renewal of breast cancer stem cells (bCSC) by a pine bark component (leelamine). Except for a few recent publications in melanoma, anticancer pharmacology of this interesting phytochemical is largely elusive. Leelamine (LLM) dose-dependently inhibited viability of MDA-MB-231 (triple-negative), MCF-7 (estrogen receptor-positive), and SUM159 (triple-negative) human breast cancer cells in association with apoptotic cell death induction. To the contrary, a normal mammary epithelial cell line derived from fibrocystic breast disease and spontaneously immortalized (MCF-10A) was fully resistant to LLM-mediated cell growth inhibition and apoptosis induction. LLM also inhibited self-renewal of breast cancer stem cells. Apoptosis induction by LLM in breast cancer cells was accompanied by a modest increase in reactive oxygen species production, which was not due to inhibition of mitochondrial electron transport chain complexes. Nevertheless, ectopic expression of manganese superoxide dismutase conferred partial protection against LLM-induced cell death but only at a lower yet pharmacologically relevant concentration. Exposure of breast cancer cells to LLM resulted in (a) induction and/or activation of multidomain proapoptotic proteins Bax and Bak, (b) caspase-9 activation, and (c) cytosolic release of cytochrome c. Bax and Bak deficiency in immortalized fibroblasts conferred significant protection against cell death by LLM. Intraperitoneal administration of LLM (7.5 mg/kg; 5 times/wk) suppressed the growth of orthotopic SUM159 xenografts in mice without any toxicity. In conclusion, the present study provides critical preclinical data to warrant further investigation of LLM. © 2016 Wiley Periodicals, Inc.

Juglanthraquinone C Induces Intracellular ROS Increase and Apoptosis by Activating the Akt/Foxo Signal Pathway in HCC Cells

Juglanthraquinone C (JC), a naturally occurring anthraquinone extracted from Juglans mandshurica, could induce apoptosis of cancer cells. This study aims to investigate the detailed cytotoxicity mechanism of JC in HepG2 and BEL-7402 cells. The Affymetrix HG-U133 Plus 2.0 arrays were first used to analyze the mRNA expression exposed to JC or DMSO in HepG2 cells. Consistent with the previous results, the data indicated that JC could induce apoptosis and hyperactivated Akt. The Western blot analysis further revealed that Akt, a well-known survival protein, was strongly activated in HepG2 and BEL-7402 cells. Furthermore, an obvious inhibitory effect on JC-induced apoptosis was observed when the Akt levels were decreased, while the overexpression of constitutively active mutant Akt greatly accelerated JC-induced apoptosis. The subsequent results suggested that JC treatment suppressed nuclear localization and increased phosphorylated levels of Foxo3a, and the overexpression of Foxo3a abrogated JC-induced apoptosis. Most importantly, the inactivation of Foxo3a induced by JC further led to an increase of intracellular ROS levels by suppressing ROS scavenging enzymes, and the antioxidant N-acetyl-L-cysteine and catalase successfully decreased JC-induced apoptosis. Collectively, this study demonstrated that JC induced the apoptosis of hepatocellular carcinoma (HCC) cells by activating Akt/Foxo signaling pathway and increasing intracellular ROS levels.

Synthesis and antitumor activities of piperazine- and cyclen-conjugated dehydroabietylamine derivatives

A series of piperazine- and cyclen-conjugated dehydroabietylamine derivatives were synthesized and characterized by 1H NMR, 13C NMR, and HRMS. The in vitro antitumor activities of conjugates 10–13 against MCF-7 and HepG-2 tumor cell lines were evaluated using CCK-8 assay. The results show that the synthesized compounds cause a dose-dependent inhibition of cell proliferation and display different antitumor activities with the IC50 values ranging from 23.56 to 78.92 μm. Moreover, the antitumor activity of conjugate 10 against the MCF-7 cell line is superior to that of the positive control 5-fluorouracil. In addition, flow cytometric assay revealed that the representative conjugate 10 could induce apoptosis in MCF-7 tumor cells in a dose-dependent manner.

Cytotoxicity effect of degraded and undegraded kappa and iota carrageenan in human intestine and liver cell lines

Background

Carrageenan is a linear sulphated polysaccharide extracted from red seaweed of the Rhodophyceae family. It has broad spectrum of applications in biomedical and biopharmaceutical field. In this study, we determined the cytotoxicity of degraded and undegraded carrageenan in human intestine (Caco-2; cancer and FHs 74 Int; normal) and liver (HepG2; cancer and Fa2N-4; normal) cell lines.

Methods

Food grade k-carrageenan (FGKC), dried sheet k-carrageenan (DKC), commercial grade k-carrageenan (CGKC), food grade i-carrageenan (FGIC) and commercial grade i-carrageenan (CGIC) were dissolved in hydrochloric acid and water to prepare degraded and undegraded carrageenan, respectively. Carrageenan at the concentration range of 62.5 – 2000.0 μg mL⁻¹ was used in the study. MTT assay was used to determine the cell viability while the mode of cell death was determined by May-Grunwald Giemsa (MGG) staining, acridine orange-ethidium bromide (AO/EtBr) staining, agarose gel electrophoresis and gene expression analysis.

Results

Degraded FGKC, DKC and CGKC showed IC₅₀ in 24, 48 and 72 hours treated Caco-2, FHs 74 Int, HepG2 and Fa2N-4 cell lines as tested by MTT assay. Degraded FGIC and CGIC only showed its toxicity in Fa2N-4 cells. The characteristics of apoptosis were demonstrated in degraded k-carrageenan treated Caco-2, FHs 74 Int, HepG2 and Fa2N-4 cells after MGG staining. When Caco-2 and HepG2 cells were undergone AO/EtBr staining, chromatin condensation and nuclear fragmentation were clearly seen under the microscope. However, DNA ladder was only found in HepG2 cells after gel electrophoresis analysis. Degraded k-carrageenan also inactivated PCNA, Ki-67 and survivin gene in HepG2. On the other hand, undegraded FGKC, DKC, CGKC, FGIC and CGIC treated cells showed no cytotoxic effect after analyzed by the same analyses as in degraded carrageenan.

Conclusion

Degraded k-carrageenan inhibited cell proliferation in Caco-2, FHs 74 Int, HepG2 and Fa2N-4 cell lines and the anti-proliferative effect was related to apoptosis together with inactivation of cell proliferating genes as determined by morphological observation and molecular analysis. However, no cytotoxic effect was found in undegraded carrageenan towards normal and cancer intestine and liver cell lines.

Synthetic derivatives of aromatic abietane diterpenoids and their biological activities

Naturally occurring aromatic abietane diterpenoids (dehydroabietanes) exhibit a wide range of biological activities. A number of synthetic studies aimed at modifying the abietane skeleton in order to obtain new potential chemotherapeutic agents have been reported. In this study, the biological activities of synthetic derivatives of aromatic abietane diterpenoids are reviewed.

Alantolactone induces cell apoptosis partially through down-regulation of testes-specific protease 50 expression

Testes-specific protease 50 (TSP50) is aberrantly expressed in many cancer biopsies and plays a crucial role in tumorigenesis, which make it a potential cancer therapeutic target for drug discovery. Here, we constructed a firefly luciferase reporter driven by the TSP50 gene promoter to screen natural compounds capable of inhibiting the expression of TSP50. Then we identified alantolactone, a sesquiterpene lactone, could efficiently inhibit the promoter activity of TSP50 gene, further results revealed that alantolactone also efficiently inhibited the expression of TSP50 in both mRNA and protein levels. Moreover, we found alantolactone could increase the ratio of Bax/Bcl-2, and activate caspase-9 and caspase-3 in the cancer cells with high expression of TSP50, surprisingly, the same effects can also be observed in the same cells just by knockdown of TSP50 gene expression. Furthermore, our results suggested that overexpression of TSP50 decreased the cell sensitivity to alantolactone-induced apoptosis in those cancer cells. Taken together, these results suggest that alantolactone induces mitochondrial-dependent apoptosis at least partially via down-regulation of TSP50 expression.