Targeted induction of apoptosis for cancer therapy: current progress and prospects

Cell Death Pathway Regulation by Functional Nanomedicines for Robust Antitumor Immunity

Cancer immunotherapy has become a mainstream cancer treatment over traditional therapeutic modes. Cancer cells can undergo programmed cell death including ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis which are find to have intrinsic relationships with host antitumor immune response. However, direct use of cell death inducers or regulators may bring about severe side effects that can also be rapidly excreted and degraded with low therapeutic efficacy. Nanomaterials are able to carry them for long circulation time, high tumor accumulation and controlled release to achieve satisfactory therapeutic effect. Nowadays, a large number of studies have focused on nanomedicines-based strategies through modulating cell death modalities to potentiate antitumor immunity. Herein, immune cell types and their function are first summarized, and state-of-the-art research progresses in nanomedicines mediated cell death pathways (e.g., ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis) with immune response provocation are highlighted. Subsequently, the conclusion and outlook of potential research focus are discussed.

Phytochemical Characterization, Antimicrobial Activity and In Vitro Antiproliferative Potential of Alchemilla vulgaris Auct Root Extract against Prostate (PC-3), Breast (MCF-7) and Colorectal Adenocarcinoma (Caco-2) Cancer Cell Lines

Despite the proven biological activity of the aerial part extract of Alchemilla vulgaris, scarce information is available about the activity of the root extract. This encouraged us to initiate the current investigation to study the cytotoxic activity of A. vulgaris methanolic root extract against various cancer cell lines in vitro, along with its antimicrobial activity and phytochemical screening. MTT assay was applied to test the cytotoxic effect against the prostate (PC-3), breast (MCF-7) and colorectal adenocarcinoma (Caco-2), together with normal Vero cells. Flow cytometry was employed to assess cell cycle arrest and apoptosis vs. necrosis in PC-3 cells. The expression of apoptosis-related genes (BAX, BCL2 and P53) was quantified by qRT-PCR analysis. The obtained results showed strong antiproliferative activity on the three cancer cell lines and the normal Vero cells in a dose-dependent manner. A high selectivity index (SI) was recorded against the three cell lines with PC-3 cells showing the highest SI and the lowest IC50. This effect was associated with cell cycle arrest at G1 phase and induction of total apoptosis at 27.18% being mainly early apoptosis. Apoptosis induction was related to the upregulation of the proapoptotic genes P53 and BAX and the downregulation of the antiapoptotic gene BCL2. Additionally, the extract demonstrated in vitro antibacterial activity against Agrobacterium tumefaciens, Serratia marcescens and Acinetobacter johnsoni. Additionally, it showed antifungal activity against Rhizoctonia solani, Penicillium italicum and Fusarium oxysporium. Seven phenolic acids and seven flavonoids were detected. The predominant phenolic acids were cinnamic and caffeic acids, while hisperdin and querestin were the principal flavonoids. These findings provide clear evidence about the promising proapoptotic effect of A. vulgaris root extract, which contributes to laying the basis for broader and in-depth future investigations.

Azadirachta indica A. Juss Fruit Mesocarp and Epicarp Extracts Induce Antimicrobial and Antiproliferative Effects against Prostate (PC-3), Breast (MCF-7), and Colorectal Adenocarcinoma (Caco-2) Cancer Cell Lines through Upregulation of Proapoptotic Genes

Effective alternative strategies and methodological approaches are critically necessary for cancer prevention and therapy. In this study, we investigated the antitumor potential of neem fruit mesocarp and epicarp extracts. The chemical composition of the derived extracts was characterized using GC–MS. Data were collected on the antimicrobial activity of the extracts in addition to the cytotoxicity effect evaluated against PC-3, MCF-7, and Caco-2 cancer cell lines, compared with the normal Vero cells. Cell-cycle arrest, apoptosis, and expression of apoptosis-related genes were assessed on PC-3 cells. Both extracts had significant antiproliferative effects on all tested cell lines in a dose-dependent manner, with the mesocarp extract being more potent. Both extracts also showed high antibacterial and antifungal activities. These results were related to the chemical constituents of the extracts identified by the GC–MS analysis. The extract of neem fruit mesocarp caused cell-cycle arrest at G2/M phase of PC-3 cells. The cytotoxicity of neem mesocarp extract is strongly correlated with the induction of apoptosis, where it caused downregulation of the antiapoptotic BCL2 gene but upregulation of the proapoptotic P53 and BAX genes. This study showed that neem fruit extract is potential anticancer material in the future.

Effects of radiofrequency radiation on apoptotic and antiapoptotic factors in colorectal cancer cells

In this study, it is aimed to investigate the effect of radiofrequency radiation (RFR) on apoptotic and antiapoptotic factors under different exposure conditions in human colonic adenocarcinoma cells (Caco-2). We analyzed the effects of 2.5 GHz continuous wave and 3 GPP modulated radiofrequency radiation exposure (15 min on, 15 min off) for 1 h and (1 h on, 1 h off) for 3 hours on Caco-2 cell lines. The cell viability of Caco-2 cells was determined by XTT method. Then, the cells were analyzed by flow cytometry to determine the effects on apoptosis staining with AnnexinV-FITC and PI. Protein expression levels of Bcl-2, Bax, Caspase-3 and Survivin were subsequently analyzed by using flow cytometric methods. Bax, Caspase 8, and Survivin protein levels were also analyzed by western blot. The cell viability rates were not significantly different after 2.5 GHz of RFR exposure for 1 h, but RFR exposure for 3 h at 2.5 GHz frequencies caused a decrease on cell viability of Caco-2 cells. RFR exposure for 1 and 3 hours at 2.5 GHz frequencies resulted in an apoptotic response. Protein analyses of Bcl-2, Bax, Survivin, Caspase-3, and Caspase-8 showed that RFR led to increase the levels of proapoptotic Bax, Caspase-3, and Caspase 8 in Caco-2 cells under different exposure conditions. However, 3-h exposure caused a decrease in antiapoptotic survivin levels. The results of our study indicate that RFR exposure affects the cell death mechanism due to apoptotic pathway.

Inhibition of ClC-5 suppresses proliferation and induces apoptosis in cholangiocarcinoma cells through the Wnt/β-catenin signaling pathway

Chloride channel-5 (ClC-5), an important branch of the ClC family, is involved in the regulation of the proliferation and cell-fate of a variety of cells, including tumor cells. However, its function in cholangiocarcinoma (CCA) cells remains enigmatic. Here, we discovered that ClC-5 was up-regulated in CCA tissues and CCA cell lines, while ClC-5 silencing inhibited CCA cell proliferation and induced apoptosis. Further mechanism studies revealed that ClC-5 inhibition could inhibit Wnt/β-catenin signaling activity and further activate the mitochondria apoptotic pathway in CCA cells. Furthermore, rescuing Wnt/β-catenin signaling activation eliminated the anti-tumor function of ClC-5 knockdown. Together, our research findings illustrated that ClC-5 inhibition plays an anti-tumor role in CCA cells via inhibiting the activity of the Wnt/β-catenin pathway, which in turn activates the mitochondrial apoptotic pathway.

A Hybrid Imaging Platform(CT/PET/FMI) for Evaluating Tumor Necrosis and Apoptosis in Real-Time

Multimodality imaging is an advanced imaging tool for monitoring tumor behavior and therapy in vivo. In this study, we have developed a novel hybrid tri-modality system that includes two molecular imaging methods: positron emission computed tomography (PET) and fluorescence molecular imaging (FMI) and the anatomic imaging modality X-ray computed tomography (CT). The following paper describes the system development. Also, its imaging performance was tested in vitro (phantom) and in vivo, in Balb/c nude mice bearing a head and neck tumor xenograft treated with novel gene therapy [a new approach to the delivery of recombinant bacterial gene (IL-24-expressing strain)]. Using the tri-modality imaging system, we simultaneously monitored the therapeutic effect, including the apoptotic and necrotic induction within the tumor in vivo. The apoptotic induction was examined in real-time using an 18F-ML-10 tracer; the cell death was detected using ICG. A CT was used to evaluate the anatomical situation. An increased tumor inhibition (including tumor growth and tumor cell apoptosis) was observed in the treatment group compared to the control groups, which further confirmed the therapeutic effect of a new IL-24-expressing strain gene therapy on the tumor in vivo. By being able to offer concurrent morphological and functional information, our system is able to characterize malignant tissues more accurately. Therefore, this new tri-modality system (PET/CT/FMI) is an effective imaging tool for simultaneously investigating and monitoring tumor progression and therapy outcomes in vivo.

Small molecule CDS-3078 induces G2/M phase arrest and mitochondria-mediated apoptosis in HeLa cells

The tumor suppressor p53 serves important roles in cell cycle arrest and apoptosis, and its activation increases the sensitivity of cancer cells to radiotherapy or chemotherapy. In the present study, the small molecule 2-[1-(4-(benzyloxy)phenyl)-3-oxoisoindolin-2-yl)-2-(4-methoxyphenyl)] acetic acid (CDS-3078) significantly increased p53 mRNA expression levels in a dose-dependent manner. Treatment with CDS-3078 increased p53 expression levels and p53-mediated activation of its downstream target genes in HeLa cells. Additionally, p53^+/+ HeLa cells treated with CDS-3078 presented with dysfunctional mitochondria, as indicated by the decrease in Bcl-2 levels, the increase in Bcl-2 homologous antagonist killer and the increase in cytochrome c release from the mitochondria to the cytoplasm. The present results suggested that CDS-3078 treatment significantly induced G₂/M phase cell cycle arrest. Therefore, CDS-3078 administration induced apoptosis via p53-mediated cell cycle arrest, causing mitochondrial dysfunction and resulting in apoptotic cell death in cervical cancer cells. Collectively, the present results suggested that CDS-3078 may be a potential anticancer agent.

Phytochemical constituents and anticancer activities of Tarchonanthus camphoratus essential oils grown in Saudi Arabia

Tarchonanthus Camphoratus L. is traditionally known for its various medicinal purposes. In this study, the T. camphoratus essential oil (TCEO) was isolated via steam distillation, and its chemical constituents were determined using GC-MS. The in vitro antiproliferative effects of TCEO on A549, HepG2, MCF-7 cancer cells, and HUVEC non-tumor cells was investigated using an MTT assay. Flow cytometry analysis was conducted to evaluate cell cycle distribution using propidium iodide staining, and cell death mode using Annexin V-FITC/PI assays. The expression of some apoptosis related genes was investigated using qRT-PCR. Major constituents of TCEO included fenchol, borneol, 3-cyclohexene-1-methanol and 3-ethyl-3-methyl. Cell viability test showed that TCEO is highly effective against MCF-7 cells with IC50 12.5 µg/mL. Cell cycle arrest at the G1/S phase, and apoptosis mediation were evident in the presence of TCEO. Gene expression analysis of several pro-apoptotic and anti-apoptotic genes revealed the initiation of apoptosis in TCEO-MCF-7 cells. In conclusion, our study confirms the antiproliferative activity of the T. camphoratus essential oil.

In vivo and in vitro apoptosis induced by new acaricidal ethyl-carbamates in Rhipicephalus microplus

The ability of ethyl-4-bromophenylcarbamate (LQM 919) and ethyl-4-chlorophenylcarbamate (LQM 996) to induce in vivo apoptosis of Rhipicephalus microplus ovarian cells and in vitro apoptosis of tick and mammalian cell culture was evaluated. The ovaries of engorged females treated with 1 mg mL^-1 LQM 919 or LQM 996 presented more (p < 0.001) peroxidase-TUNEL-positive labeled cells (apoptotic cells) in situ than their respective control groups, and this increase was time-dependent (p < 0.001). The majority of apoptotic cells were observed in the epithelium and ovarian pedicel. HepG2, Vero and Rm-sus cells, as well as cells from primary cultures of R. microplus salivary glands, intestine and ovaries were exposed to different concentrations of the ethyl-carbamates. Both ethyl-carbamates induced a concentration-dependent reduction in the viability of all cell types (p < 0.001). Exposure to the ethyl-carbamates increased caspase 3 activity (p < 0.01) in primary cultures and cell lines, except in HepG2 cells. Fluorescent TUNEL-positive cells were observed in all cell types treated with 600 μM LQM 919 or LQM 996. These results indicate that both ethyl-carbamates induce apoptosis of the ovarian, intestinal and salivary glands cells in R. microplus and strongly suggest that this is their main mechanism of acaricidal action.

Creatine supplementation does not promote tumor growth or enhance tumor aggressiveness in Walker-256 tumor-bearing rats

OBJECTIVES

This study aimed to analyze the effect of creatine (Cr) supplementation on tumor microenvironment, evaluating the parameters of tumor aggressiveness.

METHODS

Sixteen male Wistar rats were randomly assigned to 2 groups (n = 8/group): Tumor-bearing (T) and tumor-bearing supplemented with Cr (TCr). Cr supplementation was provided in drinking water for a total of 21 d. After 11 d of Cr supplementation (TCr group) or water (T group), Walker-256 tumor cells were inoculated subcutaneously in the right flank of all rats, which kept receiving Cr supplementation (TCr group) or water (T group) for 10 more days. The total period of the experiment was 21 d.

RESULTS

Tumor weight corresponded with approximately 3.5% ± 0.9% of animal body weight in the T group. Cr supplementation did not accelerate tumor growth or increase tumor size. The histopathological analysis demonstrated the presence of nuclear pleomorphisms and atypical nuclei, with the presence of low-differentiated tumor cells, in both groups. Cr supplementation did not alter apoptosis and cell proliferation markers, nor tumor capsule thickness and viable tumor area.

CONCLUSIONS

Cr supplementation in Walker-256 tumor-bearing rats did not induce significant changes in tumor development, and did not interfere with the parameters of tumor aggressiveness, such as the level of cell differentiation and proliferation.

Synthesis, characterization, DNA/BSA interactions and in vitro cytotoxicity study of palladium(II) complexes of hispolon derivatives

Thirteen novel palladium(II) complexes of the general formula [Pd(bipy)(O,O'-dkt)](PF₆), (where bipy is 2,2'-bipyridine and O,O'-dkt is β-diketonate ligand hispolon or its derivative) have been prepared through a metal-ligand coordination method that involves spontaneous formation of the corresponding diketonate scaffold. The obtained palladium(II) complexes have been characterized by NMR spectroscopy, ESI-mass spectrometry as well as elemental analysis. The cytotoxicity analysis indicates that most of the obtained palladium(II) complexes show promising growth inhibition in three human cancer cell lines. Flow cytometry analysis shows complex 3e could promote intracellular reactive oxygen species (ROS) accumulation and lead cancer cell death. And the suppression of ROS accumulation and the rescue of cell viability in HeLa cells by N-acetyl-L-cysteine (NAC) suggest the possible link between the increase in ROS generation and cytotoxicity of complex 3e. Flow cytometry analysis also reveal that complex 3e cause cell cycle arrest in the G2/M phase and collapse of the mitochondrial membrane potential, promote the generation of ROS and lead to tumor cell apoptosis. The interactions of complex 3e with calf thymus DNA (CT-DNA) have been evaluated by UV-Vis spectroscopy, fluorescence quenching experiments and viscosity measurements, which reveal that the complex interact with CT-DNA through minor groove binding and/or electrostatic interactions. Further, the results of fluorescence titration and site marker competitive experiment on bovine serum albumin (BSA) suggest that complex 3e can quench the fluorescence of BSA via a static quenching process and bind to BSA in Sudlow's site II.

The Association of Peroxiredoxin 4 with the Initiation and Progression of Hepatocellular Carcinoma

AIMS

Peroxiredoxin 4 (PRDX4) is a member of the peroxiredoxin family of antioxidant enzymes. Previously, we reported that PRDX4 can restrain the initiation and progression of nonalcoholic steatohepatitis by reducing local and systemic reactive oxygen species (ROS) levels. Oxidative stress is recognized as a key factor in hepatocarcinogenesis, and a high ROS level has also been found in hepatocellular carcinoma (HCC). Here, our aim is to investigate roles of PRDX4 in the initiation and progression of HCC.

RESULTS

In this study, for hepatocarcinogenesis, wild-type (WT), PRDX4 knockout (PRDX4^-/y), and human PRDX4 transgenic (hPRDX4^+/+) mice were given a weekly intraperitoneal injection of diethylnitrosamine for 25 weeks. The HCC incidence was higher in PRDX4^-/y mice than in WT or hPRDX4^+/+ mice. Intrahepatic and circulating oxidative stress and inflammatory cell infiltration in the liver were obviously decreased in hPRDX4^+/+ mice, compared with WT mice. Furthermore, in our cohort study, human HCC specimens with low expression of PRDX4 had higher ROS levels and a highly malignant phenotype, which was associated with a reduced overall survival, compared with those with high PRDX4 expression. However, in human HCC cell lines, PRDX4 knockdown led to a rapidly increased intracellular ROS level and suppressed cell proliferation, inducing cell death. Innovation and Conclusion: Our results clearly indicate that PRDX4 has an inhibitory effect in the initiation of HCC, but a dual (inhibitory or promoting) role in the progression of HCC, suggesting the potential utility of PRDX4 activators or inhibitors as therapy for different stages and phenotypes of HCC.

Decoding the sweet regulation of apoptosis: the role of glycosylation and galectins in apoptotic signaling pathways

Glycosylation and glycan-binding proteins such as galectins play an important role in the control of cell death signaling. Strikingly, very little attention has been given so far to the understanding of the molecular details behind this key regulatory network. Glycans attached to the death receptors such as CD95 and TRAIL-Rs, either alone or in a complex with galectins, might promote or inhibit apoptotic signals. However, we have just started to decode the functions of galectins in the modulation of extrinsic and intrinsic apoptosis. In this work, we have discussed the current understanding of the glycosylation-galectin regulatory network in CD95- as well as TRAIL-R-induced apoptosis and therapeutic strategies based on targeting galectins in cancer.

Effects of antioxidants on apoptosis induced by dasatinib and nilotinib in K562 cells

In clinical practice for the treatment of chronic myeloid leukemia, second generation of tyrosine kinase inhibitors such as Nilotinib (NIL) specific and potent inhibitor of the BCR/ABL kinase and Dasatinib (DAS) a inhibitor of BCR/ABL and Src family kinase were developed to clinically overcome imatinib resistance. In this study, we wanted to test the ability of some antioxidants such Resveratrol (RES) or a new recombinant mitochondrial manganese containing superoxide dismutase (rMnSOD) or δ-tocotrienol (δ-TOCO) to interact with DAS and NIL on viability, reactive oxygen species (ROS) production, lipid peroxidation, and apoptosis. To test the possible mechanisms of action of such antioxidants, we utilized N-acetyl-L-cysteine (NAC) a specific inhibitor ROS production or PP1 a specific Src tyrosine kinase inhibitor or BAPTA a specific chelator of intracellular calcium. Our data demonstrated: 1) RES, rMnSOD, δ-TOCO, and NAC, at dose used, significantly reduced the intracellular levels of MDA induced by DAS or NIL; 2) RES, rMnSOD, and δ-TOCO increased the intracellular ROS levels; 3) The increase ROS levels is related to higher levels of oligonucleosomesi induced by DAS and NIL and that NAC significantly reduced this activity. Interestingly, our data showed that apoptotic activity of DAS and NIL have significantly increased the production of oligonucleosomes by triggering excessive ROS generation as well as functionality of SERCA receptors.

Studies on the Dual Cytotoxicity and Antioxidant Properties of Berberis vulgaris Extracts and Its Main Constituent Berberine

The present study attempts to investigate the cytotoxic activity of ethanol and ethyl acetate extracts of the Moroccan Berberis vulgaris and its major component berberine, together with exploring their antioxidant properties. It also consists of studying the combination effect of berberine and S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide (NO) donor, against the human breast adenocarcinoma cell line (MCF-7). Using the MTT assay, we report a differential cytotoxic effect of ethanol and ethyl acetate extracts since the ethanol extract is more cytotoxic than the ethyl acetate one, with IC₅₀ = 3.54 μg/mL and 596.71 μg/mL, respectively. Interestingly, no cytotoxic effect was observed against normal cells. Furthermore, these extracts showed a remarkable antioxidant activity as measured by the DPPH free radicals scavenging assay. In fact, the IC₅₀ values are 69.65 μg/mL and 77.75 μg/mL for the ethanol and ethyl acetate extracts, respectively. In addition, several concentrations of berberine, when combined with the NO donor used at IC₃₀, induced a synergistic cytotoxic activity at concentrations ranging from 8.40 μM to 33.60 μM, as revealed by the combination index values, using the Chou–Talalay method. However, at the other concentrations tested, an antagonistic effect was observed. The observed cytotoxicity was related to apoptosis induction as demonstrated by the annexin-V-streptavidin FITC-staining analysis.

Synthesis of novel 1,2,3-triazole based artemisinin derivatives and their antiproliferative activity

Novel artemisinin-1,2,3-triazole derivatives show significant antiproliferative activity, and induce apoptosis and ROS generation and arrest the cell cycle at the G2/M phase.

Immunotoxin: A new tool for cancer therapy

Cancer is one of the main reasons of death in the most countries and in Iran. Immunotherapy quickly became one of the best methods of cancer treatment, along with chemotherapy and radiation. “Immunotoxin Therapy” is a promising way of cancer therapy that is mentioned in this field. Immunotoxins are made from a toxin attaching to an antibody target proteins present on cancer cells. The first-generation immunotoxins were made of a full-length toxin attached to whole monoclonal antibodies. But, these immunotoxins could bind to normal cells. DAB389IL2 was the first immunotoxin approved by the Food and Drug Administration. Current trends and researches are ongoing on finding proteins that in combination with immunotoxins have minimal immunogenicity and the most potency for target cell killing.

Silencing the livin gene enhances the cytotoxic effects of anticancer drugs on colon cancer cells

Purpose

Livin is associated with drug response in several cancers. The aim of this study was to investigate the effect of silencing the livin gene expression on anticancer drug response in colorectal cancer.

Methods

siRNA was transfected at different concentrations (0, 10, and 30nM) into HCT116 cells, then cells were treated with either 5-fluorouracil (FU)/leucovorin (LV) or oxaliplatin (L-OHP)/5-FU/LV. Cellular viability and apoptosis were evaluated following silencing of livin gene expression combined with treatment with anticancer drugs.

Results

Livin gene expression was effectively suppressed by 30nM siRNA compared with control and 10nM siRNA. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay showed that proliferation was effectively inhibited in cells treated with a combination of both siRNA and an anticancer drug, compared to cells treated with siRNA-Livin or anticancer drug alone. In particular, the combination of 30nM siRNA and L-OHP/5-FU/LV resulted in a 93.8% and 91.4% decrease, compared to untreated control or L-OHP/5-FU/LV alone, respectively. Cellular proliferation was most effectively suppressed by a combination of 30nM of siRNA and L-OHP/5-FU/LV compared to other combinations.

Conclusion

siRNA-mediated down-regulation of livin gene expression could significantly suppress colon cancer growth and enhance the cytotoxic effects of anticancer drugs such as 5-FU and L-OHP. The results of this study suggest that silencing livin gene expression in combination with treatment with anticancer drugs might be a novel cancer therapy for colorectal cancer.

Antiproliferative effect of berberine on canine mammary gland cancer cell culture

Canine mammary gland tumors are the most frequent cause of cancer in female dogs. Numerous studies using cancer cell lines and clinical trials have indicated that various natural products and antioxidants reduce or possibly prevent the development of cancer. Berberine (BBR), the most important alkaloid in the Berberidaceae, which exerts a wide range of pharmacological and biochemical effects, has drawn much attention due to its particularly high antitumor activity in vitro and in animal studies. The aim of the present study was to investigate the antiproliferative effect of BBR against a canine mammary gland carcinoma cell line (CF41.Mg) in vitro. CF41.Mg cells were cultured in RPMI-1640 medium containing 10% heat inactived fetal bovine serum (FBS) and 100 mg/ml peniciline-streptomycin. Subsequently the cells were treated with different concentrations of BBR chloride (10, 25, 50, 100 and 200 µM) at a density of 12,000 cells/well in 96-well plates. Following treatment, the MTT assay was used to detect cell viability after 24-, 48- and 72-h incubations at 37°C with 5% CO₂. The results indicated that BBR inhibited proliferation of canine mammary gland carcinoma cells, as treatment with 100 µM BBR for 24 h resulted in a significant decrease in cell viability (P<0.005). As the present study demonstrated that BBR (10-200 µM) induced cancer cell death, it is proposed that BBR may serve as a candidate agent against canine mammary tumor cells via its antiproliferative activity.

(1) H-NMR relaxometric studies of interaction between apoptosis specific MRI paramagnetic contrast agents and micellar models of apoptotic cells

(1) H-NMR was previously used to analyze the interaction between peptides (E3 and R826) selected by phage display to target apoptotic cells and phospholipidic models of these cells. In order to avoid the use of apoptotic cells and to obtain a fast evaluation of the efficiency of the potential MRI contrast agents obtained by grafting these peptides and their scramble analogs on a paramagnetic gadolinium complex, their proton relaxometric behavior was investigated in the presence of micelles mimicking healthy and apoptotic cells. Their preferential interaction with 1,2-dipalmitoyl-sn-glycero-3-phospho-l-serine micelles mimicking apoptotic cells as compared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine micelles modeling healthy cells was shown by nuclear magnetic relaxation dispersion profiles and the enhancement of the transverse proton relaxation rates at 60 MHz. The association constant values confirm the stronger interaction of the selected conjugated peptides (Ka Gd-PMN-E3(gadolinium 2,2',2'',2'''-[((4-carboxy)pyridine-2,6-diyl)bis(methylenenitrilo)]-tetrakis acetate) grafted with E3 peptide): 2.43 10(4)  m(-1) ; Ka Gd-DTPA-R826(gadolinium ((1-p-isothiocyanatobenzyl)-diethylenetriaminepentaacetate) grafted with R826 peptide): 2.91 10(4)  m(-1) ) as compared with their conjugated scrambles (Ka Gd-PMN-E3sc(gadolinium 2,2',2'',2'''-[((4-carboxy)pyridine-2,6-diyl)bis(methylenenitrilo)]-tetrakis acetate) grafted with E3 scramble peptide): 0.18 10(4)  m(-1) ; Ka Gd-DTPA-R826sc(gadolinium ((1-p-isothiocyanatobenzyl)-diethylenetriaminepentaacetate) grafted with R826 scramble peptide): 0.32 10(4)  m(-1) ) even if the conjugation of E3 and R826 seems to decrease their interaction. Copyright © 2015 John Wiley & Sons, Ltd.

Construction and characterization of gelonin and saporin plasmids for toxic gene-based cancer therapy

Toxic gene therapy (or suicidal gene therapy) is gaining enormous interest, specifically for the treatment of cancer. The success of this therapy lies in several crucial factors, including the potency of gene products to kill the transfected tumor cells and the transfection ability of the transfection vehicles. To address the potency problem, in the present study, we engineered two separate mammalian transfection plasmids (pSAP and pGEL) containing genes encoding ribosome inactivating proteins (RIPs), gelonin and saporin. After the successful preparation and amplification of the plasmids, they were tested on various cancer cell lines (HeLa, U87, 9L, and MDA-MB-435) and a noncancerous cell line (293 HEK) using polyethyleneimine (PEI) as the transfection agent. Transfection studies performed under varying gene concentration, incubation time, and gene-to-PEI ratios revealed that, compared to the treatment of pGFP (GFP expression plasmid)/PEI, both pGEL/PEI and pSAP/PEI complexes could induce significantly augmented cytotoxic effects at only 2 μg/mL gene concentration. Importantly, these cytotoxic effects were observed universally in all tested cancer cell lines. Overall, this study demonstrated the potential of pGEL and pSAP as effective gene candidates for the toxic gene-based cancer therapy.

Identification of a Dual Inhibitor of Janus Kinase 2 (JAK2) and p70 Ribosomal S6 Kinase1 (S6K1) Pathways

Bioactive phytochemicals can suppress the growth of malignant cells, and investigation of the mechanisms responsible can assist in the identification of novel therapeutic strategies for cancer therapy. Ginger has been reported to exhibit potent anti-cancer effects, although previous reports have often focused on a narrow range of specific compounds. Through a direct comparison of various ginger compounds, we determined that gingerenone A selectively kills cancer cells while exhibiting minimal toxicity toward normal cells. Kinase array screening revealed JAK2 and S6K1 as the molecular targets primarily responsible for gingerenone A-induced cancer cell death. The effect of gingerenone A was strongly associated with relative phosphorylation levels of JAK2 and S6K1, and administration of gingerenone A significantly suppressed tumor growth in vivo. More importantly, the combined inhibition of JAK2 and S6K1 by commercial inhibitors selectively induced apoptosis in cancer cells, whereas treatment with either agent alone did not. These findings provide rationale for dual targeting of JAK2 and S6K1 in cancer for a combinatorial therapeutic approach.

A Rac1 GTPase is a critical factor in the immune response of shrimp (Litopenaeus vannamei) to Vibrio alginolyticus infection

The small GTPase Rac1 acts as a molecular switch for signal transduction that regulates various cellular functions. However, its functions in crustaceans remain unclear. In this study, a cDNA encoding a RAS GTPase (LvRac1) in the Pacific white shrimp (L. vannamei) was identified and characterized. A recombinant variant of this GTPase, rLvRac1, was expressed in the model organism P. pastoris and its expression was confirmed by mass spectrometry. Biochemical assays indicated that the recombinant protein retained GTPase activity and was expressed in all of the organism's tested tissues. Injection of the bacterium V. alginolyticus into L. vannamei induced hepatopancreatic upregulation of LvRac1 expression. Moreover, knocking down LvRac1 in vivo significantly reduced the expression of the L. vannamei p53 and Cu/Zn superoxide dismutase genes (Lvp53 and LvCu/Zn SOD, respectively) while increasing that of the galectin gene (Lvgal). Hemolymph samples from control and LvRac1-silenced L. vannamei individuals were analyzed by flow cytometry, revealing that the latter exhibited significantly reduced respiratory burst activity and total hemocyte counts. Cumulative mortality in shrimp lacking LvRac1 was significantly greater than in control groups following V. alginolyticus challenge. The silencing of LvRac1 by double-stranded RNA injection thus increased the V. alginolyticus challenge sensitivity of L. vannamei and weakened its bacterial clearance ability in vivo. Suppressing LvRac1 also promoted the upregulation of Lvp53, LvCu/ZnSOD, and Lvgal following V. alginolyticus injection. Taken together, these results suggest that LvRac1 is important in the innate immune response of shrimp to V. alginolyticus infection.

Design of Cationic Multiwalled Carbon Nanotubes as Efficient siRNA Vectors for Lung Cancer Xenograft Eradication

Polo-Like Kinase (PLK1) has been identified as a potential target in cancer gene therapy via chemical or genetic inhibitory approaches. The biomedical applications of chemically functionalized carbon nanotubes (f-CNTs) in cancer therapy have been studied due to their ability to efficiently deliver siRNA intracellularly. In this study, we established the capacity of cationic MWNT-NH3(+) to deliver the apoptotic siRNA against PLK1 (siPLK1) in Calu6 tumor xenografts by direct intratumoral injections. A direct comparison with cationic liposomes was made. This study validates the PLK1 gene as a potential target in cancer gene therapy including lung cancer, as demonstrated by the therapeutic efficacy of siPLK1:MWNT-NH3(+) complexes and their ability to significantly improve animal survival. Biological analysis of the siPLK1:MWNT-NH3(+) treated tumors by qRT-PCR and Western blot, in addition to TUNEL staining confirmed the biological functionality of the siRNA intratumorally, suggesting that tumor eradication was due to PLK1 knockdown. Furthermore, by using a fluorescently labeled, noncoding siRNA sequence complexed with MWNT-NH3(+), we established for the first time that the improved therapeutic efficacy observed in f-CNT-based siRNA delivery is directly proportional to the enhanced siRNA retention in the solid tumor and subsequent uptake by tumor cells after local administration in vivo.

Delphinidin induces cytotoxicity and potentiates cytocidal effect in combination with arsenite in an acute promyelocytic leukemia NB4 cell line

The effects of delphinidin were investigated by focusing on growth inhibition, cell cycle arrest and apoptosis induction in the human acute promyelocytic leukemia (APL) NB4 cell line. Delphinidin exhibited a dose- and time-dependent cytotoxic effect against NB4 cells. Almost no cell cycle arrest, but an apparent increase in the percentage of sub-G1 cells was observed in delphinidin-treated cells. The activation of caspase-8 and -9 was observed as early as 1-h post-exposure to delphinidin, followed by the activation of caspase-3 from 3-h post-exposure. A substantial decrease in the expression level of Bid was also observed as early as 1-h post-exposure. A modest decrease in the mitochondrial membrane potential (ΔΨm) was observed at 3-h post-exposure, followed by a substantial time-dependent decrease in ΔΨm in treated cells. Delphinidin exerted more potent cytotoxicity against NB4 cells than normal peripheral blood mononuclear cells (PBMNCs). In addition, delphinidin in combination with an arsenic derivative arsenite (As(III)), which has demonstrated marked efficacy in patients with APL, achieved an enhanced cytocidal effect against NB4 cells, but lesser on PBMNCs. Treatment of NB4 cells with As(III) plus delphinidin did not increase, but decreased slightly, intracellular arsenic accumulation (As[i]) as compared to that treated with As(III) alone. These results suggested that delphinidin selectively sensitized NB4 cells to As(III), resulting in the enhancement of As(III) cytotoxicity by strengthening intrinsic/extrinsic pathway-mediated apoptosis induction, rather than affecting the As[i] levels. These observations may offer a rationale for the use of delphinidin to improve the clinical efficacy of As(III).

A review of the immune molecules in the sea cucumber

It is very important to identify and characterize the immune-related genes that respond to pathogens. Until recently, only some of the immune-related genes in sea cucumbers had been characterized. Their expression patterns after pathogen challenges have been analyzed via expressed sequence tag libraries, microarray studies and proteomic approaches. These genes include lectins, antimicrobial peptides, lysozyme, enzymes, clotting protein, pattern recognition proteins, Toll receptors, complement C3 and other humoral factors that might participate in the innate immune system of sea cucumbers. Although the participation of some of these immune molecules in the sea cucumber's innate immune defense against invading pathogens has been demonstrated, the functions of many of the molecules remain unclear. This review focuses on the discovery and functional characterization of the immune-related molecules from the sea cucumber for the first time and provides new insights into the immune mechanisms of the sea cucumber, which opens new possibilities for developing drugs for novel anti-bacterial and antiviral applications in fisheries.

Scientific contributions toward successful cancer immunotherapy in The Netherlands

This historical overview shows that immunologists and clinicians from The Netherlands have contributed in a major way to better insights in the nature of cancer immunity. This work involved elucidation of the nature of cancer-associated antigens in autologous and allogeneic settings in addition to understanding of the cellular basis of natural immune responses against cancers and of important immune evasion mechanisms. Insight into such basic immunological mechanisms has contributed to the development of innovating therapies.

Chemical synthesis, cytotoxicity, selectivity and bioavailability of 5α-androstane-3α,17β-diol derivatives

Aminosteroid derivatives represent a new family of compounds with promising antiproliferative activity over different cancer cell lines. Among all the aminosteroid derivatives synthesised in our laboratory, we have identified E-37P as one of the more potent when tested in vitro. Unfortunately, the pharmacokinetic properties of E-37P decrease its effectiveness when tested in vivo. To improve the bioavailability and increase the efficiency of aminosteroid E-37P, two series of analog compounds were synthesised by classic chemical synthesis, they were then characterized, and the concentration that inhibits 50% of cell proliferation (IC50) was determined on different cell lines. RM-133, a 5α-androstane-3α,17β-diol derivative with a quinoline nucleus at the end of the piperazine-proline side-chain at position 2β and an ethinyl at position 17α, showed very good antiproliferative activity among the five cancer cell lines studied (IC50=0.1, 0.1, 0.1, 2.0 and 1.1 μM for HL-60, MCF-7, T-47D, LNCaP and WEHI-3, respectively). Moreover, the plasmatic concentration of RM-133 at 3h, when injected subcutaneously in rats, was 2.3-fold higher than that of E-37P (151 vs 64.8 ng/mL). Furthermore, RM-133 weakly inhibited the two representative liver enzymes, CYP3A4 and CYP2D6, indicating a very low risk of drug-drug interactions. The cytotoxicity of RM-133 against normal cells was tested on peripheral blood lymphocytes (PBL) obtained from different donors and previously activated with phytohemagglutinin-L. PBL responded differently to treatment with RM-133, we observed a stimulation of cell proliferation and/or cytotoxicity in a dose-dependent manner. Based on these results, additional studies are currently underway to evaluate the selectivity of our lead compound against normal cell lines in a more detailed fashion.

Polyphyllin D induces apoptosis in U87 human glioma cells through the c-Jun NH2-terminal kinase pathway

Polyphyllin D (PD), an active component from a traditional medicinal herb Paris polyphylla, which has long been used for the treatment of cancer in Asian countries, has been found to hold significant antitumor activity in vivo or in vitro. However, there were few reports on the effects and underlying mechanism of PD on apoptosis in U87 human glioma cells. The present study was conducted to evaluate apoptotic induction of PD in U87 human glioma cells, and explore its underlying pathway. U87 glioma cells were cultured and treated with varied concentrations of PD (from 10(-8) to 10(-4) M). The inhibition of U87 glioma cell proliferation by PD was assessed by MTT assay. The apoptosis of U87 glioma cells was detected by flow cytometry, and western blot analysis was used to examine human B-cell leukemia/lymphoma 2 (Bcl-2), human Bcl-2 associated X protein (Bax), caspase-3, total-c-jun NH2-terminal kinase (t-JNK), and phosphorylation-JNK (p-JNK) protein expression in U87 human glioma cells. The treatment with PD for 24 h significantly inhibited the proliferation of U87 human glioma cells in a concentration-dependent manner. PD increased apoptosis and significantly upregulated the expression of Bax, caspase-3, and p-JNK associated with apoptosis, but downregulated antiapoptotic Bcl-2 expression in U87 human glioma cells. Our data provided evidences that PD induces apoptosis in U87 human glioma cells. This effect might be associated with the JNK pathway.

Complex changes in the apoptotic and cell differentiation programs during initiation of the hair follicle response to chemotherapy

Chemotherapy has severe side-effects for normal rapidly proliferating organs, such as hair follicle, and causes massive apoptosis in hair matrix keratinocytes followed by hair loss. To define the molecular signature of hair follicle response to chemotherapy, human scalp hair follicles cultured ex vivo were treated with doxorubicin and global microarray analysis was performed 3 hours after treatment. Microarray data revealed changes in expression of 504 genes in doxorubicin-treated hair follicles versus the controls. Among these genes, upregulations of several tumor necrosis factor family of apoptotic receptors (FAS, TRAIL receptors 1/2), as well as of a large number of the keratin-associated protein genes were seen after doxorubicin treatment. Hair follicle apoptosis induced by doxorubicin was significantly inhibited by either TRAIL neutralizing antibody or caspase 8 inhibitor, thus suggesting a novel role for TRAIL receptor signaling in mediating doxorubicin-induced hair loss. These data demonstrate that the early phase of the hair follicle response to doxorubicin includes upregulation of apoptosis-associated markers, as well as substantial re-organization of the terminal differentiation programs in hair follicle keratinocytes. These data provide an important platform for further studies towards the design of novel approaches for management of chemotherapy-induced hair loss.

Potential small-molecule activators of caspase-7 identified using yeast-based caspase-3 and -7 screening assays

Caspases-3 and -7 are at the core of the execution phase of apoptosis. The search for activators of these proteases has therefore deserved particular attention in the field of anticancer drug discovery. Here, a simplified yeast-based screening approach was developed and used to search for activators of caspases-3 and -7, followed by evaluation of the activity of the selected compounds in the human tumor cell lines HL-60 (acute promyelocytic leukemia) and MCF-7 (breast adenocarcinoma). By using the yeast approach, two potential activators of caspase-7, 5,6-dihydroxy-7-prenyloxyflavone (1a) and 3-hydroxy-7-geranyloxyflavone (2a), were identified. Unlike the known caspases-3 and -7 activator, the procaspase activating compound-1 (PAC-1), these flavonoids did not interfere with the caspase-3 activity in yeast. Moreover, flavonoids 1a and 2a processed procaspase-7 to the active caspase-7 both in yeast and in vitro processing assays, and inhibited the growth of HL-60 and MCF-7 human tumor cells with higher potencies than PAC-1, particularly in the absence of caspase-3 (MCF-7 cells). In MCF-7 cells, the flavonoids processed procaspase-7, increased its activity and sensitized these cells to the effects of the cytotoxic drug, etoposide. In conclusion, the developed yeast target-based screening assays led to the identification of potential caspase-7 activators. A proof of concept is therefore provided for the effectiveness of the yeast assays in the discovery of caspase activators. Additionally, the identified compounds may pave the way for a new class of caspase activators with improved anticancer properties.

Licochalcone B inhibits growth of bladder cancer cells by arresting cell cycle progression and inducing apoptosis

To examine the mechanisms by which licochalcone B (LCB) inhibits the proliferation of human malignant bladder cancer cell lines (T24 and EJ) in vitro and antitumor activity in vivo in MB49 (murine bladder cancer cell line) tumor model. Exposure of T24 or EJ cells to LCB significantly inhibited cell lines proliferation in a concentration-dependent and time-dependent manner, and resulted in S phase arrest in T24 or EJ cells, respectively. LCB treatment decreased the expression of cyclin A, cyclin-dependent kinase (CDK1 and CDK2) mRNA, cell division cycle 25 (Cdc25A and Cdc25B) protein. In addition, LCB treatment down-regulated Bcl-2 and survivin expression, enhanced Bax expression, activated caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) protein. Consistently, the tumorigenicity of LCB-treated MB49 cells was limited significantly by using the colony formation assay in vitro and the MB49 tumor model performed in C57BL/6 mice in vivo. These findings provide support for the use of LCB in chemoprevention and bladder cancer therapy.

Triterpene saponosides from Lysimachia ciliata differentially attenuate invasive potential of prostate cancer cells

Neither androgen ablation nor chemotherapeutic agents are effective in reducing the risk of prostate cancer progression. On the other hand, multifaceted effects of phytochemicals, such as triterpene saponins, on cancer cells have been suggested. A promising safety and tolerability profile indicate their possible application in the treatment of advanced prostate cancers. We analyzed the specificity, selectivity and versatility of desglucoanagalloside B effects on human prostate cancer cells derived from prostate cancer metastases to brain (DU-145 cells) and bone (PC-3 cells). Prominent growth arrest and apoptotic response of both cell types was observed in the presence of sub-micromolar desglucoanagalloside B concentrations. This was accompanied by cytochrome c release and caspase 3/7 activation. A relatively low cytostatic and pro-apoptotic response of cancer cells to a desglucoanagalloside B analog, anagallosaponin IV, illustrated the specificity of the effects of desglucoanagalloside B, whereas the low sensitivity of normal prostate PNT2 cells to desglucoanagalloside B showed the selectivity of its action. Inhibition of cancer cell motility was observed in the presence of both saponins, however only desglucoanagalloside B attenuated cancer cell invasive potential, predominantly through an effect on cell elastic properties. These data demonstrate the versatility of its effects on prostate cancer cells. In contrast to PNT2 cells, cancer cells tested in this study were relatively resistant to mitoxantrone. The multifaceted action of desglucoanagalloside B on basic cellular traits, crucial for prostate cancer progression, opens perspectives for elaboration of combined palliative therapies and new prostate cancer prophylaxis regimens.

Stress-related mitochondrial components and mitochondrial genome as targets of anticancer therapy

In addition to their role as cell powerhouse mitochondria are key organelles in the processes deciding about cell life or death that are crucial for tumor cell growth and survival, as well as for tumor cell ability to metastasize. Alterations in mitochondrial structure and functions have long been observed in cancer cells, thus targeting mitochondria as an anticancer therapeutic strategy has gained momentum recently. We will review the achievements and perspectives in the elucidation of the molecular basis for developing mitochondrial-targeted compounds as potential anticancer agents with special attention to mitochondrial DNA mutations and mitochondrial dysfunction. Molecules/agents candidate to affect mitochondrial metabolism in cancer cells will be dealt with, with a particular focus on approaches targeting defects in the mitochondrial genome.

Novel antitumor agent, trilacunary Keggin-type tungstobismuthate, inhibits proliferation and induces apoptosis in human gastric cancer SGC-7901 cells

A new one-dimensional chain-like compound of tungstobismuthate, [(W(OH)2)2 (Mn(H2O)3)2(Na3(H2O)14)(BiW9O33)2](Himi)2·16H2O (1) (imi = iminazole), has been synthesized in aqueous solution. The structure of 1 was identified by elemental analysis, IR, thermogravimetry (TG), X-ray photoelectron spectroscopy (XPS), (183)W-NMR, and single crystal X-ray diffraction. To investigate the inhibitory effect of 1 on human gastric adenocarcinoma SGC-7901 cells, cell proliferation and apoptosis initiation were examined by MTT assay (MTT = 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazoliumbromide), flow cytometry, nuclear staining, transmission electron microscopy, single cell gel electrophoresis, DNA fragmentation, and Western blotting. The results showed that 1 inhibited cell proliferation and induced apoptosis in SGC-7901 cells in dose-dependent manner. In addition, 1 also decreased the expression of bcl-2 protein and nuclear factor-κB p65 protein in SGC-7901 cells. And expression of bcl-2 protein exhibits a decreasing trend with increase of concentration of 1. Thus, 1 possessed a potential antitumor activity in SGC-7901 cells. This suggests that polyoxotungstates will provide a promising and novel antitumor agent in prevention and treatment of gastric adenocarcinoma.

The splicing mutant of the human tumor suppressor protein DFNA5 induces programmed cell death when expressed in the yeast Saccharomyces cerevisiae

DFNA5 was first identified as a gene responsible for autosomal dominant deafness. Different mutations were found, but they all resulted in exon 8 skipping during splicing and premature termination of the protein. Later, it became clear that the protein also has a tumor suppression function and that it can induce apoptosis. Epigenetic silencing of the DFNA5 gene is associated with different types of cancers, including gastric and colorectal cancers as well as breast tumors. We introduced the wild-type and mutant DFNA5 allele in the yeast Saccharomyces cerevisiae. The expression of the wild-type protein was well tolerated by the yeast cells, although the protein was subject of degradation and often deposited in distinct foci when cells entered the diauxic shift. In contrast, cells had problems to cope with mutant DFNA5 and despite an apparent compensatory reduction in expression levels, the mutant protein still triggered a marked growth defect, which in part can be ascribed to its interaction with mitochondria. Consistently, cells with mutant DFNA5 displayed significantly increased levels of ROS and signs of programmed cell death. The latter occurred independently of the yeast caspase, Mca1, but involved the mitochondrial fission protein, Fis1, the voltage-dependent anion channel protein, Por1 and the mitochondrial adenine nucleotide translocators, Aac1 and Aac3. Recent data proposed DFNA5 toxicity to be associated to a globular domain encoded by exon 2–6. We confirmed these data by showing that expression of solely this domain confers a strong growth phenotype. In addition, we identified a point mutant in this domain that completely abrogated its cytotoxicity in yeast as well as human Human Embryonic Kidney 293T cells (HEK293T). Combined, our data underscore that the yeast system offers a valuable tool to further dissect the apoptotic properties of DFNA5.

SKLB70326, a novel small-molecule inhibitor of cell-cycle progression, induces G₀/G₁ phase arrest and apoptosis in human hepatic carcinoma cells

We previously reported the potential of a novel small molecule 3-amino-6-(3-methoxyphenyl)thieno[2.3-b]pyridine-2-carboxamide (SKLB70326) as an anticancer agent. In the present study, we investigated the anticancer effects and possible mechanisms of SKLB70326 in vitro. We found that SKLB70326 treatment significantly inhibited human hepatic carcinoma cell proliferation in vitro, and the HepG2 cell line was the most sensitive to its treatment. The inhibition of cell proliferation correlated with G(0)/G(1) phase arrest, which was followed by apoptotic cell death. The SKLB70326-mediated cell-cycle arrest was associated with the downregulation of cyclin-dependent kinase (CDK) 2, CDK4 and CDK6 but not cyclin D1 or cyclin E. The phosphorylation of the retinoblastoma protein (Rb) was also observed. SKLB70326 treatment induced apoptotic cell death via the activation of PARP, caspase-3, caspase-9 and Bax as well as the downregulation of Bcl-2. The expression levels of p53 and p21 were also induced by SKLB70326 treatment. Moreover, SKLB70326 treatment was well tolerated. In conclusion, SKLB70326, a novel cell-cycle inhibitor, notably inhibits HepG2 cell proliferation through the induction of G(0)/G(1) phase arrest and subsequent apoptosis. Its potential as a candidate anticancer agent warrants further investigation.

Pycnidione, a fungus-derived agent, induces cell cycle arrest and apoptosis in A549 human lung cancer cells

Pycnidione, a small tropolone first isolated from the fermented broth of Theissenia rogersii 92031201, exhibits antitumor activities through an undefined mechanism. The present study evaluated the effects and mechanisms of pycnidione on the growth and death of A549 human lung cancer cells. Pycnidione significantly inhibited the proliferation of A549 cells in a concentration-dependent manner, with a 50% growth inhibition (GI(50)) value of approximately 9.3nM at 48h. Pycnidione significantly decreased the expression of cyclins D1 and E and induced G(1)-phase cell cycle arrest and a subsequent increase in the sub-G(1) phase population. Pycnidione also markedly reduced the expression of survivin and activated caspase-8 and -3, increased reactive oxygen species (ROS) generation, caused the collapse of the mitochondrial membrane potential (MMP), and enhanced PAI-1 production, thus triggering apoptosis in the A549 cells. Taken together, pycnidione exerts anti-proliferative effects on human lung cancer cells through the induction of cell cycle arrest and apoptosis. Therefore, testing of its effects in vivo is warranted to evaluate its potential as a therapeutic agent against lung cancer.

Live-attenuated measles virus vaccine confers cell contact loss and apoptosis of ovarian cancer cells via ROS-induced silencing of E-cadherin by methylation

Herein we present a novel molecular mechanism of the antitumor effects of live-attenuated measles virus (MV) vaccine in ovarian cancer. Using a 2-DE/MS-based comparative proteomics strategy, we identified 17 proteins differentially expressed in live-attenuated MV vaccine-treated SKOV-3 ovarian cancer cells, including oxidative stress-associated enzymes and cell contact-related proteins, which indicated that live-attenuated MV vaccine could induce aberrant ROS activation. It further mediated epigenetic silencing of E-cadherin via upregulating DNMT3a that conferred both cell-cell and cell-matrix contact loss and apoptosis of ovarian cancer cells. This process could be reversed through ROS inhibition. Our study lays the theoretical foundation for the clinical application of live-attenuated MV vaccine as a potential oncotherapeutic agent for ovarian cancer treatment.

Hyperforin inhibits Akt1 kinase activity and promotes caspase-mediated apoptosis involving Bad and Noxa activation in human myeloid tumor cells

BACKGROUND

The natural phloroglucinol hyperforin HF displays anti-inflammatory and anti-tumoral properties of potential pharmacological interest. Acute myeloid leukemia (AML) cells abnormally proliferate and escape apoptosis. Herein, the effects and mechanisms of purified HF on AML cell dysfunction were investigated in AML cell lines defining distinct AML subfamilies and primary AML cells cultured ex vivo.

METHODOLOGY AND RESULTS

HF inhibited in a time- and concentration-dependent manner the growth of AML cell lines (U937, OCI-AML3, NB4, HL-60) by inducing apoptosis as evidenced by accumulation of sub-G1 population, phosphatidylserine externalization and DNA fragmentation. HF also induced apoptosis in primary AML blasts, whereas normal blood cells were not affected. The apoptotic process in U937 cells was accompanied by downregulation of anti-apoptotic Bcl-2, upregulation of pro-apoptotic Noxa, mitochondrial membrane depolarization, activation of procaspases and cleavage of the caspase substrate PARP-1. The general caspase inhibitor Z-VAD-fmk and the caspase-9- and -3-specific inhibitors, but not caspase-8 inhibitor, significantly attenuated apoptosis. HF-mediated apoptosis was associated with dephosphorylation of active Akt1 (at Ser(473)) and Akt1 substrate Bad (at Ser(136)) which activates Bad pro-apoptotic function. HF supppressed the kinase activity of Akt1, and combined treatment with the allosteric Akt1 inhibitor Akt-I-VIII significantly enhanced apoptosis of U937 cells.

SIGNIFICANCE

Our data provide new evidence that HF's pro-apoptotic effect in AML cells involved inhibition of Akt1 signaling, mitochondria and Bcl-2 members dysfunctions, and activation of procaspases -9/-3. Combined interruption of mitochondrial and Akt1 pathways by HF may have implications for AML treatment.

Resveratrol suppresses constitutive activation of AKT via generation of ROS and induces apoptosis in diffuse large B cell lymphoma cell lines

Background

We have recently shown that deregulation PI3-kinase/AKT survival pathway plays an important role in pathogenesis of diffuse large B cell lymphoma (DLBCL). In an attempt to identify newer therapeutic agents, we investigated the role of Resveratrol (trans-3,4′, 5-trihydroxystilbene), a naturally occurring polyphenolic compound on a panel of diffuse large B-cell lymphoma (DLBCL) cells in causing inhibition of cell viability and inducing apoptosis.

Methodology/Principal Findings

We investigated the action of Resveratrol on DLBCL cells and found that Resveratrol inhibited cell viability and induced apoptosis by inhibition of constitutively activated AKT and its downstream targets via generation of reactive oxygen species (ROS). Simultaneously, Resveratrol treatment of DLBCL cell lines also caused ROS dependent upregulation of DR5; and interestingly, co-treatment of DLBCL with sub-toxic doses of TRAIL and Resveratrol synergistically induced apoptosis via utilizing DR5, on the other hand, gene silencing of DR5 abolished this effect.

Conclusion/Significance

Altogether, these data suggest that Resveratrol acts as a suppressor of AKT/PKB pathway leading to apoptosis via generation of ROS and at the same time primes DLBCL cells via up-regulation of DR5 to TRAIL-mediated apoptosis. These data raise the possibility that Resveratrol may have a future therapeutic role in DLBCL and possibly other malignancies with constitutive activation of the AKT/PKB pathway.

The Role of PPARs in Cancer

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. PPARalpha is mainly expressed in the liver, where it activates fatty acid catabolism. PPARalpha activators have been used to treat dyslipidemia, causing a reduction in plasma triglyceride and elevation of high-density lipoprotein cholesterol. PPARdelta is expressed ubiquitously and is implicated in fatty acid oxidation and keratinocyte differentiation. PPARdelta activators have been proposed for the treatment of metabolic disease. PPARgamma2 is expressed exclusively in adipose tissue and plays a pivotal role in adipocyte differentiation. PPARgamma is involved in glucose metabolism through the improvement of insulin sensitivity and represents a potential therapeutic target of type 2 diabetes. Thus PPARs are molecular targets for the development of drugs treating metabolic syndrome. However, PPARs also play a role in the regulation of cancer cell growth. Here, we review the function of PPARs in tumor growth.