Curcumin induces apoptosis and inhibits growth of human Burkitt's lymphoma in xenograft mouse model

Phytocompounds and Nanoformulations for Anticancer Therapy: A Review

Cancer is a complex disease that affects millions of people and remains a major public health problem worldwide. Conventional cancer treatments, including surgery, chemotherapy, immunotherapy, and radiotherapy, have limited achievements and multiple drawbacks, among which are healthy tissue damage and multidrug-resistant phenotype onset. Increasing evidence shows that many plants' natural products, as well as their bioactive compounds, have promising anticancer activity and exhibit minimal toxicity compared to conventional anticancer drugs. However, their widespread use in cancer therapy is severely restricted by limitations in terms of their water solubility, absorption, lack of stability, bioavailability, and selective targeting. The use of nanoformulations for plants' natural product transportation and delivery could be helpful in overcoming these limitations, thus enhancing their therapeutic efficacy and providing the basis for improved anticancer treatment strategies. The present review is aimed at providing an update on some phytocompounds (curcumin, resveratrol, quercetin, and cannabinoids, among others) and their main nanoformulations showing antitumor activities, both in vitro and in vivo, against such different human cancer types as breast and colorectal cancer, lymphomas, malignant melanoma, glioblastoma multiforme, and osteosarcoma. The intracellular pathways underlying phytocompound anticancer activity and the main advantages of nanoformulation employment are also examined. Finally, this review critically analyzes the research gaps and limitations causing the limited success of phytocompounds' and nanoformulations' clinical translation.

Curcumin as a Potential Therapeutic Agent in Certain Cancer Types

Cancer is a devastating disease condition and is the second most common etiology of death globally. After decades of research in the field of hematological malignancies and cellular therapeutics, we are still looking for therapeutic agents with the most efficacies and least toxicities. Curcumin is one of the cancer therapeutic agents that is derived from the Curcuma longa (turmeric) plant, and still in vitro and in vivo research is going on to find its beneficial effects on various cancers. Due to its potency to affect multiple targets of different cellular pathways, it is considered a promising agent to tackle various cancers alone or in combination with the existing chemotherapies. This review covers basic properties, mechanism of action, potential targets (molecules and cell-signaling pathways) of curcumin, as well as its effect on various solid and hematological malignancies. 

Curcumin sensitizes Epstein-Barr-immortalized lymphoblastoid cell lines to inorganic arsenic toxicity

Chronic exposure to inorganic arsenic (iAs) through contaminated drinking water is an important health problem in certain countries. The use of phytochemicals such as curcumin has recently emerged as an alternative strategy for preventing cellular damage caused by iAs. The Epstein-Barr virus (EBV) affects ~90% of the population and experimental evidence suggested that curcumin mediates cytotoxicity against EBV-infected cells. Due to the potential for an interaction of these factors, the aim of the present study was to evaluate the effect of this phytochemical on iAs-related toxicity in EBV-infected cells. Two independent EBV-immortalized human lymphoblastoid cell lines (LCLs) were used as the model. The cell lines were first incubated with increasing concentrations of curcumin or iAs for 24 and 15 h, respectively, to determine the individual effects of each exposure on cell death. In the next experiment, cell cultures were pre-incubated with 5 µM curcumin for 9 h prior to treatment with 10 µM iAs for 15 h, followed by evaluation of cell death and the cell cycle profile via flow cytometry. The results indicated that individual treatment with either curcumin or iAs induced cell death in a concentration-dependent manner. Furthermore, curcumin pre-treatment enhanced iAs-induced cell death and promoted cell cycle arrest in G1 phase. Taken together, these results suggested that curcumin sensitizes EBV-positive LCLs to the cytotoxic effects of iAs.

Molecular targets for the management of cancer using Curcuma longa Linn. phytoconstituents: A Review

Medicinal plants are being used for therapeutic purposes since the dawn of human civilization. The therapeutic efficacy of medicinal plants is due to the presence of wide range phytochemical constituents or secondary metabolites. The medicinal plants are traditionally used for several types of ailments. Even in those pathological conditions where other methods of treatment fail to work. Curcuma longa Linn is very common ingredient used as spice in foods as preservative and coloring material in different part of the world. It has been used as a home remedy for a variety of diseases. Curcuma longa and its isolated constituent curcumin are widely evaluated for anticancer activity. Curcumin possesses broad remedial potential due to its multi-targeting effect against many different carcinoma including leukemia, genitourinary cancers, gastrointestinal cancers and breast cancer etc. Hence, Curcumin has potential for the development of new medicine for the treatment of several diseases.

MiR-28-5p mediates the anti-proliferative and pro-apoptotic effects of curcumin on human diffuse large B-cell lymphoma cells

OBJECTIVE

To investigate the anti-proliferative and pro-apoptotic effects of curcumin on diffuse large B-cell lymphoma (DLBCL) cells and explore the mechanism.

METHODS

OCI-LY7 cells were treated with curcumin (2.5, 5, 10, 20, and 40 μM) for 24, 48, or 72 hours. Cell viability and apoptosis were determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium bromide assay and TdT-mediated dUTP nick-end labeling staining, respectively. MiR-28-5p expression was detected via qRT-PCR. The binding site of miR-28-5p was predicted using online databases and verified using the dual-luciferase reporter assay. MiR-28-5p overexpression and inhibition were achieved via transfection with an miR-28-5p mimic and inhibitor, respectively.

RESULTS

Curcumin decreased the viability of OCI-LY7 cells in a concentration- and time-dependent manner, and these effects were attenuated by miR-28-5p inhibition. MiR-28-5p expression was upregulated by curcumin. Curcumin increased the numbers of apoptotic cells and upregulated cleaved caspase-3 expression, and these effects were attenuated by miR-28-5p inhibition. The dual-luciferase reporter assay confirmed that miR-28-5p directly targets the 3'-untranslated region of BECN1. Curcumin downregulated BECN1 and microtubule-associated protein 1 light chain 3 beta-II/I expression and upregulated p62 expression.

CONCLUSIONS

Our results described the curcumin exerted anti-proliferative and pro-apoptotic effects on OCI-LY7 cells through a mechanism potentially involving miR-28-5p.

Curcumin inhibits liver metastasis of gastric cancer through reducing circulating tumor cells

Primary gastric cancer (PGC) is the fourth most common malignant human cancer and the second leading cause of death worldwide. The majority of the subjects of PGC is diagnosed at a late stage, resulting in poor prognosis and therapeutic outcome, largely attributable to dissemination of tumor cells into circulation as circulating tumor cells (CTCs) and their formation of distal tumor. Curcumin is an active ingredient from the rhizome of the plant Curcuma longa. Here, we assessed whether treatment with Curcumin may reduce the incidence of metastatic tumor formation in liver in mice carrying PGC. We found that Curcumin treatment significantly reduced the presence of CTCs and formation of liver tumor. Mechanistically, Curcumin reduced CXCR4 expression in PGCs in vitro and in vivo, and thus likely inhibited metastasis of PGC through suppression of stromal cell -derived factor-1/CXCR4 signaling. Thus, our study suggests that Curcumin may inhibit liver metastasis of PGC through reducing CTCs.

Curcumin and Cancer

Curcumin, a polyphenol extracted from Curcuma longa in 1815, has gained attention from scientists worldwide for its biological activities (e.g., antioxidant, anti-inflammatory, antimicrobial, antiviral), among which its anticancer potential has been the most described and still remains under investigation. The present review focuses on the cell signaling pathways involved in cancer development and proliferation, and which are targeted by curcumin. Curcumin has been reported to modulate growth factors, enzymes, transcription factors, kinase, inflammatory cytokines, and proapoptotic (by upregulation) and antiapoptotic (by downregulation) proteins. This polyphenol compound, alone or combined with other agents, could represent an effective drug for cancer therapy.

Synthesis of novel coumarin nucleus-based DPA drug-like molecular entity: In vitro DNA/Cu(II) binding, DNA cleavage and pro-oxidant mechanism for anticancer action

Despite substantial research on cancer therapeutics, systemic toxicity and drug-resistance limits the clinical application of many drugs like cisplatin. Therefore, new chemotherapeutic strategies against different malignancies are needed. Targeted cancer therapy is a new paradigm for cancer therapeutics which targets pathways or chemical entities specific to cancer cells than normal ones. Unlike normal cells, cancer cells contain elevated copper which plays an integral role in angiogenesis. Copper is an important metal ion associated with chromatin DNA, particularly with guanine. Thus, targeting copper via copper-specific chelators in cancer cells can serve as an effective anticancer strategy. New pharmacophore di(2-picolyl)amine (DPA)-3(bromoacetyl) coumarin (ligand-L) was synthesized and characterized by IR, ESI-MS, 1H- and 13C-NMR. Binding ability of ligand-L to DNA/Cu(II) was evaluated using a plethora of biophysical techniques which revealed ligand-L-DNA and ligand-L-Cu(II) interaction. Competitive displacement assay and docking confirmed non-intercalative binding mode of ligand-L with ctDNA. Cyclic voltammetry confirmed ligand-L causes quasi reversible Cu(II)/Cu(I) conversion. Further, acute toxicity studies revealed no toxic effects of ligand-L on mice. To evaluate the chemotherapeutic potential and anticancer mechanism of ligand-L, DNA damage via pBR322 cleavage assay and reactive oxygen species (ROS) generation were studied. Results demonstrate that ligand-L causes DNA cleavage involving ROS generation in the presence of Cu(II). In conclusion, ligand-L causes redox cycling of Cu(II) to generate ROS which leads to oxidative DNA damage and pro-oxidant cancer cell death. These findings will establish ligand-L as a lead molecule to synthesize new molecules with better copper chelating and pro-oxidant properties against different malignancies.

CELLFOOD™ induces apoptosis in human mesothelioma and colorectal cancer cells by modulating p53, c-myc and pAkt signaling pathways

BACKGROUND

CELLFOOD™ (CF) is a nutraceutical non-addictive, non-invasive, and completely non-toxic unique proprietary colloidal-ionic formula. Little is known about its effect on cancer cells in solid tumors. The aim of this study was to evaluate the effect that CF has on different cancer cell lines and the mechanism by which the nutraceutical works.

METHODS

The effect of CF on HFF (normal fibroblasts), Met5A (mesothelium), MSTO-211H, NCI-2452, Ist-Mes1, MPP89, Ist-Mes2 (mesothelioma), M14 (melanoma), H1650, H1975 (lung cancer), SKRB3 (breast cancer), and HCT-116 (colorectal cancer) cell growth was tested by cell proliferation and clonogenic assay. Among all of them, MSTO-211 and HCT-116 were analyzed for cell cycle by flow cytometry and western blot.

RESULTS

All human cancer lines were suppressed on cell growth upon 1:200 CF treatment for 24 and 48 hours. Death was not observed in HFF and Met5A cell lines. Cell cycle analysis showed an increased sub-G1 with reduction of G1 in MSTO-211 and a cell cycle arrest of in G1 in HCT116. Activation of caspase-3 and cleavage of PARP confirmed an apoptotic death for both cell lines. Increased expression levels of p53, p21, and p27, downregulation of c-myc and Bcl-2, and inhibition of Akt activation were also found in CF-treated MSTO-211 and HCT-116 cells.

CONCLUSIONS

These findings ascertained an interaction between p53, c-myc, p21, p27, Bcl-2, PI3K/Akt pathway, and CF-induced apoptosis in MSTO-211H and HCT-116 cells, suggesting that CF acts as an important regulator of cell growth in human cancer cell lines. CF could be a useful nutraceutical intervention for prevention in colon cancer and mesothelioma.

The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer

This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.

Stable and potent analogues derived from the modification of the dicarbonyl moiety of curcumin

Curcumin has shown promising therapeutic utilities for many diseases, including cancer; however, its clinical application is severely limited because of its poor stability under physiological conditions. Here we find that curcumin also loses its activity instantaneously in a reducing environment. Curcumin can exist in solution as a tautomeric mixture of keto and enol forms, and the enol form was found to be responsible for the rapid degradation of the compound. To increase the stability of curcumin, several analogues were synthesized in which the diketone moiety of curcumin was replaced by isoxazole (compound 2) and pyrazole (compound 3) groups. Isoxazole and pyrazole curcumins were found to be extremely stable at physiological pH, in addition to reducing atmosphere, and they can kill cancer cells under serum-depleted condition. Using molecular modeling, we found that both compounds 2 and 3 could dock to the same site of tubulin as the parent molecule, curcumin. Interestingly, compounds 2 and 3 also show better free radical scavenging activity than curcumin. Altogether, these results strongly suggest that compounds 2 and 3 could be good replacements for curcumin in future drug development.

Curcuma Contra Cancer? Curcumin and Hodgkin's Lymphoma

Curcumin, a phytochemical isolated from curcuma plants which are used as coloring ingredient for the preparation of curry powder, has several activities which suggest that it might be an interesting drug for the treatment or prevention of cancer. Curcumin targets different pathways which are involved in the malignant phenotype of tumor cells, including the nuclear factor kappa B (NFKB) pathway. This pathway is deregulated in multiple tumor entities, including Hodgkin’s lymphoma (HL). Indeed, curcumin can inhibit growth of HL cell lines and increases the sensitivity of these cells for cisplatin. In this review we summarize curcumin activities with special focus on possible activities against HL cells.

Curcumin in various cancers

Curcumin (diferuloylmethane), an active constituent of turmeric, is a well-described phytochemical, which has been used since ancient times for the treatment of various diseases. The dysregulation of cell signaling pathways by the gradual alteration of regulatory proteins is the root cause of cancers. Curcumin modulates regulatory proteins through various molecular mechanisms. Several research studies have provided in-depth analysis of multiple targets through which curcumin induces protective effects against cancers including gastrointestinal, genitourinary, gynecological, hematological, pulmonary, thymic, brain, breast, and bone. The molecular mechanisms of action of curcumin in treating different types of cancers remain under investigation. The multifaceted role of this dietary agent is mediated through its inhibition of several cell signaling pathways at multiple levels. Curcumin has the ability to inhibit carcinogenicity through the modulation of the cell cycle by binding directly and indirectly to molecular targets including transcription factors (NF-kB, STAT3, β-catenin, and AP-1), growth factors (EGF, PDGF, and VEGF), enzymes (COX-2, iNOS, and MMPs), kinases (cyclin D1, CDKs, Akt, PKC, and AMPK), inflammatory cytokines (TNF, MCP, IL-1, and IL-6), upregulation of proapoptotic (Bax, Bad, and Bak) and downregulation of antiapoptotic proteins (Bcl(2) and Bcl-xL). A variety of animal models and human studies have proven that curcumin is safe and well tolerated even at very high doses. This study elaborates the current understanding of the chemopreventive effects of curcumin through its multiple molecular pathways and highlights its therapeutic value in the treatment and prevention of a wide range of cancers.

Curcumin improves the antitumor effect of X-ray irradiation by blocking the NF-κB pathway: an in-vitro study of lymphoma

Curcumin, a phenolic compound from the rhizomes of Curcuma longa, inhibits the growth of a variety of malignant cell types including lymphoma cells. We investigated the role of curcumin in modulating the response of Burkitt's lymphoma cells to ionizing radiation (IR) in vitro and explored the mechanisms that mediated this effect. We treated three Burkitt's lymphoma cell lines with vehicle, curcumin, IR, and curcumin in combination with IR. Cell viability, apoptosis, and cell cycle distribution were determined to ascertain the radiosensitization effect of curcumin. Nuclear factor-kappa B (NF-κB) activation was assessed by nuclear translocation of p65. Apoptosis-related proteins were monitored by western blot assay and real-time RT-PCR. Pretreatment of curcumin sensitized lymphoma cells to IR-induced apoptosis and increased G2/M phase arrest in the cell cycle distribution. Accordingly, the antiapoptotic Bcl-xL protein, cell cycle modulating protein CDC2, and cyclin B1 were downregulated by the curcumin treatment. IR activated NF-κB as evidenced by an increased nuclear p65 translocation and cytoplasmic IκBα expression. However, pretreatment with curcumin significantly decreased the nuclear translocation of p65 and cytoplasmic IκBα degradation. Survivin and hexokinase II, downstream effectors of NF-κB that mediate the antiapoptotic effect of NF-κB, were suppressed by the pretreatment of curcumin. These observations suggest that the activated NF-κB pathway plays a prosurvival role in Burkitt's lymphoma in response to IR. Curcumin blocks this pathway and has therapeutic potential for improving the antitumor effects of radiotherapy.

A novel anti-lymphoma protein RE26 from Rozites emodensis (Berk.) Moser

A novel antitumor protein, designated RE26, with anti-lymphoma activity was purified from a Tris-HCl buffer extract of Rozites emodensis (Berk.) Moser by three successive steps of ion exchange chromatography. SDS-PAGE and gel filtration chromatography revealed that RE26 is a monomeric protein of 26 kDa, and isoelectrofocusing assay indicated its isoelectric point of 4.3-4.4. RE26 has high stability over a wide pH range (pH 3-11) but is sensitive to temperature and only stable under 40 °C. Partial amino acid sequences of two RE26 peptide fragments were determined by Edman degradation as GLEEEETLLLLFFPP and GTEQE. The half-maximal inhibitory concentration (IC₅₀) of RE26 against tested lymphoma cell lines was around 4 μg/ml. In vitro experiments showed that RE26 could specifically bind to lymphoma cells; activate the caspases, including caspases 3, 8, and 9 in host cells; and induce apoptosis. Experiments in nude mice indicated local RE26 injection adjacent to tumor site could inhibit lymphoma formation.

Curcumin Induces Apoptosis in EJ Bladder Cancer Cells via Modulating C-Myc and PI3K/Akt Signaling Pathway

Background

Cancer chemopreventive agent curcumin has been shown to possess cell growth inhibition and apoptosis induction properties in several types of cancer. However, the detailed molecular mechanisms of the compound remain far from clear in EJ bladder cancer cells.

Methods

The effect of curcumin on EJ cell growth and apoptosis was detected by MTT assays and flow cytometry. The phosphorylation levels of PTEN, PDK1, Akt, GSK-3β, c-Raf, and Bad and the expression levels of c-myc, Bax, Bcl-2, caspase-9, caspase-7, caspase-3, and PARP following curcumin administration were examined by immunoblots.

Results

Curcumin suppressed the growth of EJ cells in a time and concentration dependent manner. Immunoblot showed that curcumin increased expression levels of c-myc and inhibited the activation of PI3K/Akt pathway in a time-dependent manner in EJ cells. Activation of PTEN, GSK-3β, c-Raf, caspase-9, caspase-7, and caspase-3, cleavage of PARP, upregulation of Bad and Bax, and downregulation of Akt and Bcl-2 were also found in curcumin-treated EJ cells.

Conclusions

These findings establish a mechanistic linkup or interaction between c-myc, Bax, Bad, Bcl-2, caspase cascades, PI3K/Akt pathway and curcumin- induced apoptosis of EJ cells, suggesting that c-myc and PI3K/Akt signaling pathway play important roles in curcumin-induced apoptosis of EJ bladder cancer cells.

In vitro effects of plant and mushroom extracts on immunological function of chicken lymphocytes and macrophages

1. The present study was conducted to examine the effects of organic extracts from milk thistle (Silybum marianum), turmeric (Curcuma longa), reishi mushroom (Ganoderma lucidum), and shiitake mushroom (Lentinus edodes) on innate immunity and tumor cell viability. 2. Innate immunity was measured by lymphocyte proliferation and nitric oxide production by macrophages, and the inhibitory effect on tumor cell growth was assessed using a non-radioactive assay. For measuring the cytokine levels in the HD11 macrophages which were treated with extracts of turmeric or shiitake mushroom, the levels of mRNAs for interferon-alpha (IFN- alpha), interleukin-1beta (IL-1beta), IL-6, IL-12, IL-15, IL-18, and tumor necrosis factor superfamily 15 (TNFSF15) were quantified by real time RT-PCR. 3. In vitro culture of chicken spleen lymphocytes with extracts of milk thistle, turmeric, and shiitake and reishi mushrooms induced significantly higher cell proliferation compared with the untreated control cells. Stimulation of macrophages with extracts of milk thistle and shiitake and reishi mushrooms, but not turmeric, resulted in robust nitric oxide production to levels that were similar with those induced by recombinant chicken interferon-gamma. All extracts uniformly inhibited the growth of chicken tumor cells in vitro at the concentration of 6.3 through 100 microg/ml. Finally, the levels of mRNAs encoding IL-1beta, IL-6, IL-12, IL-18, and TNFSF15 were enhanced in macrophages that were treated with extracts of turmeric or shiitake mushroom compared with the untreated control. 4. These results document the immunologically-based enhancement of innate immunity in chickens by extracts of plants and mushrooms with known medicinal properties in vitro. In vivo studies are being planned to delineate the cellular and molecular mechanisms responsible for their mechanism of action.

A natural compound, methyl angolensate, induces mitochondrial pathway of apoptosis in Daudi cells

Natural products discovered from medicinal plants have played an important role in the treatment of cancer. In an effort to identify novel small molecules which can affect the proliferation of lymphoma cells, we tested methyl angolensate (MA), a plant derived tetranortriterpenoid, purified from the crude extract of the root callus of Soymida febrifuga commonly known as Indian red wood tree. We have tested MA for its cytotoxic properties on Burkitt's lymphoma cell lines, using various cellular assays. We observed that MA induces cytotoxicity in Daudi cells in a dose-dependent manner using trypan blue, MTT and LDH assays. We find that the treatment with MA led to activation of DNA double-strand break repair proteins including KU70 and KU80, suggesting the activation of nonhomologous DNA end joining pathway in surviving cells. Further, we find that methyl angolensate could induce apoptosis by cell cycle analysis, annexin V-FITC staining, DNA fragmentation and PARP cleavage. Besides, MA treatment led to reactive oxygen species generation and loss of mitochondrial transmembrane potential. These results suggest the activation of mitochondrial pathway of apoptosis. Hence, we identify MA as a potential chemotherapeutic agent against Daudi cells.

Curcumin derivatives: molecular basis of their anti-cancer activity

Curcumin, a phenolic compound from the plant Curcuma longa L., has shown a wide-spectrum of chemopreventive, antioxidant and antitumor properties. Although its promising chemotherapeutic activity, preclinical and clinical studies highlight Curcumin limited therapeutic application due to its instability in physiological conditions. To improve its stability and activity, many derivatives have been synthesized and studied, among which bis-DemethoxyCurcumin (bDMC) and diAcetylCurcumin (DAC). In this report, we show that both bDMC and DAC are more stable than Curcumin in physiological medium. To explore the mechanism of their chemotherapeutic effect, we studied their role in proliferation in the HCT116 human colon cancer cells. We correlated kinetic stability and cellular uptake data to their biological effects. Both bDMC and DAC impair correct spindles formation and induce a p53- and p21(CIP1/WAF1)-independent mitotic arrest, which is more stable and long-lasting for bDMC. A subsequent p53/p21(CIP1/WAF1)-dependent inhibition of G1 to S transition is triggered by Curcumin and DAC as a consequence of the mitotic slippage, preventing post-mitotic cells from re-entering the cell cycle. Conversely, the G1/S arrest induced by bDMC is a direct effect of the drug and concomitant to the mitotic block. Finally, we demonstrate that bDMC induces rapid DNA double-strand breaks, moving for its possible development in anti-cancer clinical applications.

The heat shock protein 27 (Hsp27) operates predominantly by blocking the mitochondrial-independent/extrinsic pathway of cellular apoptosis

Heat shock protein 27 (Hsp27) is a molecular chaperone protein which regulates cell apoptosis by interacting directly with the caspase activation components in the apoptotic pathways. With the assistance of the Tat protein transduction domain we directly delivered the Hsp27 into the myocardial cell line, H9c2 and demonstrate that this protein can reverse hypoxia-induced apoptosis of cells. In order to characterize the contribution of Hsp27 in blocking the two major apoptotic pathways operational within cells, we exposed H9c2 cells to staurosporine and cobalt chloride, agents that induce mitochondria-dependent (intrinsic) and -independent (extrinsic) pathways of apoptosis in cells respectively. The Tat-Hsp27 fusion protein showed a greater propensity to inhibit the effect induced by the cobalt chloride treatment. These data suggest that the Hsp27 predominantly exerts its protective effect by interfering with the components of the extrinsic pathway of apoptosis.