Isoflavones inhibit the clonogenicity of human colon cancer cells

In Silico HCT116 Human Colon Cancer Cell-Based Models En Route to the Discovery of Lead-Like Anticancer Drugs

To discover new inhibitors against the human colon carcinoma HCT116 cell line, two quantitative structure–activity relationship (QSAR) studies using molecular and nuclear magnetic resonance (NMR) descriptors were developed through exploration of machine learning techniques and using the value of half maximal inhibitory concentration (IC₅₀). In the first approach, A, regression models were developed using a total of 7339 molecules that were extracted from the ChEMBL and ZINC databases and recent literature. The performance of the regression models was successfully evaluated by internal and external validations, the best model achieved R² of 0.75 and 0.73 and root mean square error (RMSE) of 0.66 and 0.69 for the training and test sets, respectively. With the inherent time-consuming efforts of working with natural products (NPs), we conceived a new NP drug hit discovery strategy that consists in frontloading samples with 1D NMR descriptors to predict compounds with anticancer activity prior to bioactivity screening for NPs discovery, approach B. The NMR QSAR classification models were built using 1D NMR data (¹H and ¹³C) as descriptors, from 50 crude extracts, 55 fractions and five pure compounds obtained from actinobacteria isolated from marine sediments collected off the Madeira Archipelago. The overall predictability accuracies of the best model exceeded 63% for both training and test sets.

Biological evaluation of 2-pyrazolinyl-1-carbothioamide derivatives against HCT116 human colorectal cancer cell lines and elucidation on QSAR and molecular binding modes

In the search of compounds exhibiting anticancer activity, 37 derivatives of 2-pyrazolinyl-1-carbothioamide were designed and synthesized. Clonogenic cell survival assays were adapted to measure the cytotoxicities of the synthetic derivatives against HCT116 human colon cancer cell lines. Half-maximal cell growth inhibitory concentrations (GI₅₀) ranged from 0.49 to 41.22µM. The compound with the lowest GI₅₀ value, 3-(2-hydroxy-4,5-dimethoxyphenyl)-5-(naphthalen-1-yl)-N-(3,4,5-trimethoxyphenyl)-pyrazolinyl-1-carbothioamide, was subjected to further biological studies, including cell viability and apoptosis assays to examine levels of annexin-V in the outer plasma membrane layer and poly ADP-ribose polymerase cleavage. Additionally, in vitro kinase assays were performed, and Abelson murine leukemia viral oncogene homolog 1 (Abl 1) tyrosine kinase demonstrated good inhibitory activity. The binding mode between the compound of interest and Abl 1 was elucidated using in silico docking. The pharmacophores derived for 2-pyrazolinyl-1-carbothioamides based on their quantitative structure-activity relationships will help us design novel chemotherapeutic agents.

Anticancer and structure-activity relationship evaluation of 3-(naphthalen-2-yl)-N,5-diphenyl-pyrazoline-1-carbothioamide analogs of chalcone

To identify new potent chemotherapeutic agents, we synthesized compounds with 3-(naphthalen-2-yl)-N,5-diphenyl-pyrazoline-1-carbothioamide (NDPC) skeletons and evaluated their cytotoxicities using a clonogenic long-term survival assay. Their half-maximal cell growth inhibitory concentrations ranged from a few hundred nanomolars to a few micromolars. Further biological experiments including flow cytometry and western blotting analysis were performed with the derivative showing the best cytotoxicity. To identify a target protein of the selected compound, an in vitro kinase assay was carried out, which revealed that aurora kinases A and B were inhibited by the test compound, and this was confirmed using western blot analysis. The molecular binding mode between the selected compound and the kinases was elucidated using in silico docking. The structural conditions required for good cytotoxicity were identified based on the quantitative relationships between the physicochemical properties of the derivatives and their cytotoxicities.

Colorectal anticancer activities of polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamides

To develop potent chemotherapeutic agents for treating colorectal cancers, polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamide derivatives were designed. Twenty-two novel derivatives were synthesized and their cytotoxicities were measured using a clonogenic long-term survival assay. Of these derivatives, 3-(1-hydroxynaphthalen-2-yl)-N-(3-methoxyphenyl)-5-(4-methoxyphenyl)-pyrazoline-1-carbothioamide (NPC 15) exhibited the best half-maximal cell growth inhibitory concentrations (196.35nM). To explain its cytotoxicity, further biological experiments were performed. Treatment with NPC 15 inhibited cell cycle progression and triggered apoptosis through the caspase-mediated pathway. Its inhibitory effects on several kinases participating in the cell cycle were investigated using an in vitro kinase assay. Its half-maximal inhibitory concentrations for aurora kinases A and B were 105.03μM and 8.53μM, respectively. Further analysis showed that NPC 15 decreased phosphorylation of aurora kinases A, B, and C and phosphorylation of histone H3, a substrate of aurora kinases A and B. Its molecular binding mode for aurora kinase B was elucidated using in silico docking. In summary, polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamides could be potent chemotherapeutic agents.

Estrogenic activity of isoflavonoids from the stem bark of the tropical tree Amphimas pterocarpoides, a source of traditional medicines

Various preparations of the African tree Amphimas pterocarpoides Harms are traditionally used to treat endocrine- related adverse health conditions. In the ovariectomized rat, the enriched in phenolics fraction of the methanol extract of stem bark of A. pterocarpoides acted as vaginotrophic agent of considerably weaker uterotrophic activity compared to estradiol. Evaluation of the fraction and 11 isoflavonoids isolated therefrom using Ishikawa cells and estrogen receptor (ER) isotype-specific reporter cells suggested that the estrogenic activity of the fraction could be attributed primarily to daidzein and dihydroglycitein and secondarily to glycitein. The potency-based selectivity of daidzein, dihydroglycitein and glycitein for gene expression through ERβ versus ERα, expressed relative to estradiol, was 37, 27 and 20, respectively. However, the rank order of relative-to-estradiol potencies of induction of alkaline phosphatase in Ishikawa cells, a reliable marker of estrogenic activity, was daidzein>dihydroglycitein>>glycitein. The considerably higher estrogenic activity of dihydroglycitein compared to glycitein could be attributed to the partial agonist/antagonist activity of dihydroglycitein through ERβ. Calculation of theoretical free energies of binding predicted the partial agonism/antagonism of dihydroglycitein through ERβ. The fraction and the isolated isoflavonoids promoted lactogenic differentiation of HC11 mammary epithelial cells at least as effectively as premenopausal levels of estradiol. This data suggests that the estrogenic activity of the fraction likely depends on the metabolism of glycitein to dihydroglycitein; that the fraction could exert vaginotrophic activity likely without challenging endocrine cancer risk more than estrogen-alone supplementation; and that the fraction's safety for the reproductive track warrants a more detailed evaluation.

Quantitative Relationships Between the Cytotoxicity of Flavonoids on the Human Breast Cancer Stem-Like Cells MCF7-SC and Their Structural Properties

As some breast cancer-related deaths can be attributed to the metastasis of cancer stem cells, chemotherapeutic agents targeting breast cancer stem cells are of interest as a potential treatment. Flavonoids that exhibit cytotoxicity on breast cancer stem cells have rarely been observed. Thus, the objective of this study was to measure potential cytotoxic effects of 42 different flavonoids on the human breast cancer stem-like cell line, MCF7-SC. The relationship between flavonoid structural properties and cytotoxicity has not been reported previously; therefore, we determined quantitative structure-activity relationships using both comparative molecular field analysis and comparative molecular similarity analysis. Further biological experiments including Western blot analysis, flow cytometry, and immunofluorescence microscopy were also conducted on the most cytotoxic 8-chloroflavanone.

Synthesis and biological evaluation of phenyl-1H-1,2,3-triazole derivatives as anti-inflammatory agents

Rapid and efficient synthesis of a phenyl-1H-1,2,3-triazole library enabled cost-effective biological testing of a range of novel non-steroidal anti-inflammatory drugs with potential for improved drug efficacy and toxicity profiles. Anti-inflammatory activities of the phenyl-1H-1,2,3-triazole analogs synthesized in this report were assessed using the xylene-induced ear edema model in mice. At least four analogs, 2a, 2b, 2c, and 4a, showed more potent effects than the reference anti-inflammatory drug diclofenac at the same dose of 25 mg/kg. To explore relationships between the structural properties of phenyl-1H-1,2,3-triazole analogs and their anti-inflammatory activities in xylene-induced ear edema, comparative molecular field analysis was performed, and pharmacophores showing good anti-inflammatory activities were identified based on an analysis of contour maps obtained from comparative molecular field analysis. The anti-inflammatory effect on the molecular level was tested by the expression of tumor necrosis factor-alpha induced COX-2 using Western blots. Because the addition of the analog 2c caused the expression change of TNF-α induced COX-2, the molecular binding mode between 2c and COX-2 was elucidated using in silico docking.

Scaffold and cell line based approaches for QSAR studies on anticancer agents

Importance of 2D QSAR in drug discovery, lower number of descriptors containing models shows best statistical parameters, number of involved scaffolds in models affects the statistical values.

Flavonoids promoting HaCaT migration: I. Hologram quantitative structure-activity relationships

Cell migration plays an important role in multicellular development and preservation. Because wound healing requires cell migration, compounds promoting cell migration can be used for wound repair therapy. Several plant-derived polyphenols are known to promote cell migration, which improves wound healing. Previous studies of flavonoids on cell lines have focused on their inhibitory effects and not on wound healing. In addition, studies of flavonoids on wound healing have been performed using mixtures. In this study, individual flavonoids were used for cellular migration measurements. Relationships between the cell migration effects of flavonoids and their structural properties have never been reported. Here, we investigated the migration of keratinocytes caused by 100 flavonoids and examined their relationships using hologram quantitative structure-activity relationships. The structural conditions responsible for efficient cell migration on keratinocyte cell lines determined from the current study will facilitate the design of flavonoids with improved activity.

Isorhamnetin suppresses colon cancer cell growth through the PI3K‑Akt‑mTOR pathway

Isorhamnetin, a flavonoid isolated from the fruits of herbal medicinal plants, such as Hippophae rhamnoides L., exerts anticancer effects similar to other flavonoids. However, the effect of isorhamnetin on colorectal cancer (CRC) and the underlying molecular mechanism are unclear. This study aimed to determine the effect of isorhamnetin on the proliferation of cells from the human CRC cell lines, HT‑29, HCT116 and SW480. It was demonstrated that isorhamnetin suppressed the proliferation of cells from all three cell lines, induced cell cycle arrest at the G2/M phase and suppressed cell proliferation by inhibiting the PI3K‑Akt‑mTOR pathway. Isorhamnetin also reduced the phosphorylation levels of Akt (ser473), phosph‑p70S6 kinase and phosph‑4E‑BP1 (t37/46) protein, and enhanced the expression of Cyclin B1 protein. Therefore, this compound was revealed to be a selective PI3K‑Akt‑mTOR pathway inhibitor, and may be a potent anticancer agent for the treatment of CRC, as it restrains the proliferation of CRC cells.

Design, synthesis and inhibitory activities of naringenin derivatives on human colon cancer cells

Based on the previous result, several naringenin derivatives modified at position 7 with bulky substituents were designed and synthesized, and their inhibitory effects on HCT116 human colon cancer cells were tested using a clonogenic assay. The half maximal inhibitory concentrations (IC(50)) of five naringenin derivatives ranged between 1.20 μM and 20.01 μM which are much better than naringenin used as a control. In addition, new structural modification at C-4 of flavanone results in improving both the anti-cancer effect and anti-oxidative effect. In vitro cyclin dependent kinase 2 (CDK2) binding assay was carried out based on the previous results. To elucidate the possible interaction between naringenin derivatives and CDK2, in silico docking study was performed. This result demonstrates the rationale for the different inhibitory activities of the naringenin derivatives. These findings could be used for designing cancer therapeutic or preventive flavanone-derived agents.