Trilliumosides K and L, two novel steroidal saponins from rhizomes of Trillium govanianum, as potent anti-cancer agents targeting apoptosis in the A-549 cancer cell line.

Two novel steroidal saponins, trilliumosides K (1) and L (2), were isolated from the rhizomes of Trillium govanianum led by bioactivity-guided phytochemical investigation along with seven known compounds: govanoside D (3), protodioscin (4), borassoside E (5), 20-hydroxyecdysone (6), 5,20-hydroxyecdysone (7), govanic acid (8), and diosgenin (9). The structure of novel compounds 1-2 was established using analysis of spectroscopic data including 1D and 2D nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HR-ESI-MS) data. All isolated compounds were evaluated for in vitro cytotoxic activity against a panel of human cancer cell lines. Compound 1 showed significant cytotoxic activity against the A-549 (Lung) and SW-620 (Colon) cancer cell lines with IC50 values of 1.83 and 1.85 µM, respectively whereas the IC50 value of Compound 2 against the A-549 cell line was found to be 1.79 µM. Among the previously known compounds 3, 5, and 9, the cytotoxic IC50 values were found to be in the range of 5-10 µM. Comprehensive anti-cancer investigation revealed that Compound 2 inhibited in vitro migration and colony-forming capability in the A-549 cell line. Additionally, the mechanistic analysis of Compound 2 on the A-549 cell line indicated distinctive alterations in nuclear morphology, increased reactive oxygen species (ROS) production, and decreased levels of mitochondrial membrane potential (MMP). By upregulating the pro-apoptotic protein BAX and downregulating the anti-apoptotic protein BCL-2, the aforementioned actions eventually cause apoptosis, a crucial hallmark in cancer research, which activates Caspase-3. To the best of our knowledge, this study reports the first mechanistic anti-cancer evaluation of the compounds isolated from the rhizomes of T. govanianum with remarkable cytotoxic activity in the desired micromolar range.

Antiproliferative activity of diarylnaphthylpyrrolidine derivative via dual target inhibition.

Breast cancer is the second leading cause of deaths in women globally. Present communication deals with design and synthesis of a few diarylnaphthyls as possible anti-breast cancer agents. Among the thirty three representatives with significant antiproliferative activity compounds 23 and 50 were quite efficacious against human breast cancer cells. Compound 50 induced apoptosis in both MCF-7 and MDA-MB-231 cells and exerted S phase and G2/M phase arrest respectively via distinct mechanistic pathways. It showed moderate microtubule destabilization. Further, it exhibited DNA topoisomerase-II inhibition effect in MCF-7 cells. It was well tolerable and found safe up to 300 mg/kg dose in Swiss albino mice. The dual action antiproliferative effect of compound 50 is quite interesting and warrants for future development.

Antiproliferative efficacy of curcumin mimics through microtubule destabilization.

Curcumin possesses an attractive chemical structure with highly conjugated diferuloylmethane core. Curcumin mimics have been designed and prepared with an additional bridged phenyl ring in conjugation. Fourteen diverse analogues were evaluated against a panel of human cancer cell lines. The best analogue of the series i.e. compound 6a exhibited potent cytotoxicity against A431, epidermoid carcinoma cell line (IC50 = 1.5 µM) and DLD1, colorectal adenocarcinoma cell line (IC50 = 6.9 µM). In tubulin kinetics experiment, compound 6a destabilized polymerisation process (IC50 = 4.68 µM). In cell cycle analysis, compound 6a exerted G2/M phase arrest in A431 cells and induced apoptosis. In Ehrlich Ascites Carcinoma in Swiss-albino mice, compound 6a showed 78.6% tumour reduction at 80 mg/kg dose and 57% solid tumour reduction at 150 mg/kg dose. Further, in acute-oral toxicity experiment in rodent model, compound 6a was given in three different oral doses to Swiss albino mice. There were non-significant changes in various biochemical parameters and major body organs studied, including their absolute and relative weights. It was tolerable up to 300 mg/kg dose in Swiss-albino mice. The present study shows that the novel curcumin mimic 6a is a safe and efficacious anticancer compound. However, it needs to be optimized for better efficacy.

Anticancer activity of gallic acid template-based benzylidene indanone derivative as microtubule destabilizer.

Benzylidene indanones have been designed and synthesized from gallic acid, a plant phenolic acid as possible anticancer agent. The best analogue of the series, that is, 3-(3',4',5'-trimethoxyphenyl)-4,5,6-trimethoxy-2-(4˝-nitrobenzylidene)-indan-1-one (8) exhibited potent cytotoxicity (IC50 =3-10 µm) against several human cancer cell lines through microtubule destabilization (IC50 =1.54 µm) after occupying colchicine-binding site of ß-tubulin. In cell cycle analysis, compound 8 exerted G2/M phase arrest in both MCF-7 and MDA-MB-231 cells and induced apoptosis. It reduced 34.8% solid tumor in in vivo Ehrlich ascite carcinoma in Swiss albino mice at 30 mg/kg dose. In acute oral toxicity experiment, it was tolerable up to 300 mg/kg doses in Swiss albino mice. The lead compound 8 needs to be optimized for better activity.

A novel microtubule depolymerizing colchicine analogue triggers apoptosis and autophagy in HCT-116 colon cancer cells.

Colchicine is a tubulin-binding natural product isolated from Colchicum autumnale. Here we report the in vitro anticancer activity of C-ring modified semi-synthetic derivative of colchicine; N-[(7S)-1,2,3-trimethoxy-9-oxo-10-(4-phenyl-piperidin-1-yl)-5,6,7,9 tetrahydrobenzo[a]heptalen-7-yl]acetamide (4h) on colon cancer HCT-116 cell line. The compound 4h was screened for anti-proliferative activity against different human cancer cell lines and was found to exhibit higher cytotoxicity against colon cancer cell lines HCT-116 and Colo-205 with IC50 of 1 and 0.8 µM respectively. Cytotoxicity of the compound to the normal fR2 breast epithelial cells and normal HEK293 human embryonic kidney cells was evaluated in concentration and time-dependent manner to estimate its selectivity for cancer cells which showed much better selectivity than that of colchicine. Compound 4h induced cell death in HCT-116 cells by activating apoptosis and autophagy pathways. Autophagy inhibitor 3-MA blocked the production of LC3-II and reduced the cytotoxicity in response to 4h, but did not affect apoptosis, suggesting thereby that these two were independent events. Reactive oxygen species scavenger ascorbic acid pretreatment not only decreased the reactive oxygen species level but also reversed 4h induced cytotoxicity. Treatment with compound 4h depolymerized microtubules and the majority of cells arrested at the G2/M transition. Together, these data suggest that 4h has better selectivity and is a microtubule depolymerizer, which activates dual cell-death machineries, and thus, it could be a potential novel therapeutic agent in cancer therapy.

The augmented anticancer potential of AP9-cd loaded solid lipid nanoparticles in human leukemia Molt-4 cells and experimental tumor.

AP9-cd, a novel lignan composition from Cedrus deodara has significant anticancer potential, and to further enhance its activity, it was lucratively encumbered into solid lipid nanoparticles (SLNs). These nanoparticles were formulated by micro-emulsion technique with 70% drug trap competence. AP9-cd-SLNs were regular, solid, globular particles in the range of 100-200 nm, which were confirmed by electron microscopic studies. Moreover, AP9-cd-SLNs were found to be stable for up to six months in terms of color, particle size, zeta potential, drug content and entrapment. AP9-cd-SLNs have 30-50% higher cytotoxic and apoptotic potential than the AP9-cd alone. The augmented anticancer potential of AP9-cd-SLNs was observed in cytotoxic IC50 value, apoptosis signaling cascade and in Ehrlich ascites tumor (EAT) model. AP9-cd-SLNs induce apoptosis in Molt-4 cells via both intrinsic and extrinsic pathway. Moreover, the dummy nanoparticles (SLNs without AP9-cd) did not have any cytotoxic effect in cancer as well as in normal cells. Consequently, SLNs of AP9-cd significantly augment the apoptotic and antitumor potential of AP9-cd. The present study provides a podium for ornamental the remedial latent via novel delivery systems like solid lipid nanoparticles.

Anticancer activity and toxicity profiles of 2-benzylidene indanone lead molecule.

3-(3',4',5'-Trimethoxyphenyl)-4,5,6-trimethoxy,2-(3″,4″-methylenedioxybenzylidene)-indan-1-one (1) is an optimized anti-cancer lead molecule obtained on modification of gallic acid, a plant phenolic acid. It exhibited potent cytotoxicities (IC50=0.010-14.76µM) against various human carcinoma cells. In cell cycle analysis, benzylidene indanone 1 induced G2/M phase arrest in both MCF-7 and MDA-MB-231 cells. It also induced apoptosis in DU145 cells which was evident by cleavage of PARP. In Ehrlich ascites carcinoma, benzylidene indanone 1 showed 45.48% inhibition of tumour growth at 20mg/kg dose in Swiss albino mice. Further, in sub-acute toxicity experiment in Swiss-albino mice, it was found to be non-toxic up to 100mg/kg dose for 28days. The lead compound benzylidene indanone 1 can further be optimized for better anti-cancer activity.

Inhibition of phosphotidylinositol-3 kinase pathway by a novel naphthol derivative of betulinic acid induces cell cycle arrest and apoptosis in cancer cells of different origin.

Betulinic acid (BA) is a pentacyclic triterpenoid natural product reported to inhibit cell growth in a variety of cancers. However, the further clinical development of BA got hampered because of poor solubility and pharmacological properties. Interestingly, this molecule offer several hotspots for structural modifications in order to address its associated issues. In our endeavor, we selected C-3 position for the desirable chemical modification in order to improve its cytotoxic and pharmacological potential and prepared a library of different triazoline derivatives of BA. Among them, we previously reported the identification of a potential molecule, that is, 3{1N(5-hydroxy-naphth-1yl)-1H-1,2,3-triazol-4yl}methyloxy betulinic acid (HBA) with significant inhibition of cancer cell growth and their properties. In the present study, we have shown for the first time that HBA decreased the expression of phosphotidylinositol-3 kinase (PI3K) p110α and p85α and caused significant downregulation of pAKT and of NFκB using human leukemia and breast cancer cells as in vitro models. Further it was revealed that PI3K inhibition by HBA induced cell cycle arrest via effects on different cell cycle regulatory proteins that include CDKis cyclins and pGSK3ß. Also, this target-specific inhibition was associated with mitochondrial apoptosis as was reflected by the increased expression of mitochondrial bax, downregulated bcl2 and decreased mitochondrial levels of cytochrome c, together with reactive oxygen species generation and decline in mitochondrial membrane potential. The apoptotic effectors such as caspase 8, caspase 9 and caspase 3 were found to be upregulated besides DNA repair-associated enzyme, that is, PARP cleavage caused cancer cell death. Pharmacodynamic evaluation revealed that both HBA and BA were safe upto the dose of 2000 mg/kg body weight and with acceptable pharmacodynamic parameters. The in vitro data corroborated with in vivo anticancer activity wherein Ehrlich solid tumor showed that HBA as a more potent agent than BA without any body weight loss and mortality.

Enhanced anticancer potential of encapsulated solid lipid nanoparticles of TPD: a novel triterpenediol from Boswellia serrata.

A pentacyclic triterpenediol (TPD) from Boswellia serrata has significant cytotoxic and apoptotic potential in a large number of human cancer cell lines. To enhance its anticancer potential, it was successfully formulated into solid lipid nanoparticles (SLNs) by the microemulsion method with 75% drug entrapment efficiency. SEM and TEM studies indicated that TPD-SLNs were regular, solid, and spherical particles in the range of 100-200 nm, and the system indicated that they were more or less stable upon storing up to six months. TPD loaded SLNs showed significantly higher cytotoxic/antitumor potential than the parent drug. TPD-SLNs have 40-60% higher cytotoxic and apoptotic potential than the parent drug in terms of IC(50), extent of apoptosis, DNA damage, and expression of pro-apoptotic proteins like TNF-R1, cytochrome-c, and PARP cleavage in HL-60 cells. Moreover, blank SLNs did not have any cytotoxic effect on the cancer as well as in normal mouse peritoneal macrophages. The in vivo antitumor potential of TPD-SLNs was significantly higher than that of TPD alone in Sarcoma-180 solid tumor bearing mice. Therefore, SLNs of TPD successfully increased the apoptotic and anticancer potential of TPD at comparable doses (both in vitro and in vivo). This work provides new insight into improvising the therapeutic efficacy of TPD by adopting novel delivery strategies such as solid lipid nanoparticles.

Chemically standardized isolates from Cedrus deodara stem wood having anticancer activity.

An isolate "CD lignan mixture" comprising lignans from stem wood of Cedrus deodara consisted of (-)-wikstromal (75 - 79%), (-)-matairesinol (9 - 13%) and benzylbutyrolactol (7 - 11%) and was studied for its in vitro cytotoxicity against human cancer cell lines. The in vivo anticancer activity of CD lignan mixture was studied using Ehrlich ascites carcinoma and colon carcinoma (CA-51) models in mice. Its effect was also studied on annexin V binding, intracellular caspases and DNA fragmentation to gain insight into the mode of action. In vitro cytotoxicity studies showed significant dose-dependent effects against several cancer cell lines from different tissues such as breast, cervix, neuroblastoma, colon, liver, and prostate at 10, 30 and 100 microg/mL. The IC (50) values varied from 16.4 ng/mL to 116.03 microg/mL depending on the cell line. Comparative data of IC (50) values of CD lignan mixture showed a synergistic effect in comparison to the individual molecules, i. e., (-)-matairesinol, (-)-wikstromol present in CD lignan mixture . CD lignan mixture had the most pronounced effect on CNS cell lines followed by colon. The tumor regression observed with Ehrlich ascites carcinoma and CA-51 was 53% and approximately 54%, respectively, when CD lignan mixture was given at 300 mg/kg, I. P. for nine days in the Ehrlich ascites carcinoma model and 400 mg/kg, I. P. for the same period in the CA-51 model. It was comparable with 5-fluorouracil at 22 mg/kg and 20 mg/kg, respectively. CD lignan mixture at 10, 30 and 100 microg/mL increased the percentage of annexin V positive HL-60 cells to 1.9 - 17.18% as compared to control (1.04%). In K562 cells CD lignan mixture at 10, 30 or 100 microg/mL and staurosporine (1 microM) showed 9.13%, 11.38%, 17.22% and 28.07% intracellular caspases activation, respectively. A distinct DNA laddering pattern was observed for treatment with the CD lignan mixture in HL-60, K562 (30 microg/mL and 100 microg/mL) and MOLT-4 cells (30 microg/mL) after 24 h incubation. DNA cell cycle analysis indicated that CD lignan mixture at 10, 30 and 100 microg/mL increased the content of hypodiploid (sub G(1) phase) cells when compared to control (2.55, 5.4 and 6.25% vs. 0.27%). The present study indicates that CD lignan mixture has cytotoxic potential against human cancer cell lines. It has the ability to induce tumor regression in vivo. It induces apoptosis as indicated by annexin V positive cells, induction of intracellular caspases, DNA fragmentation and DNA cell cycle analysis.