Exploring the anti-myeloma potential of composite nanoparticles As4S4/Fe3O4: Insights from in vitro, ex vivo and in vivo studies.

Given the profound multiple myeloma (MM) heterogeneity in clonal proliferation of malignant plasma cells (PCs) and anti-MM therapeutic potential of nanotherapies, it is inevitable to develop treatment plan for patients with MM. Two composite nanoparticles (NPs), As4S4/Fe3O4 (4:1) and As4S4/Fe3O4 (1:1) demonstrated effective anti-MM activity in in vitro, ex vivo, and in vivo in xenograft mouse model. Composite NPs triggered activation of p-ERK1/2/p-JNK, and downregulation of c-Myc, p-PI3K, p-4E-BP1; G2/M cell cycle arrest with increase in cyclin B1, histones H2AX/H3, activation of p-ATR, p-Chk1/p-Chk2, p-H2AX/p-H3; and caspase- and mitochondria-dependent apoptosis induction. NPs attenuated the stem cell-like side population in MM cells, both alone and in the presence of stroma. For a higher clinical response rate, As4S4/Fe3O4 (4:1) observed synergism with dexamethasone and melphalan, while As4S4/Fe3O4 (1:1) showed synergistic effects in combination with bortezomib, lenalidomide and pomalidomide anti-MM agents, providing the framework for further clinical evaluation of composite NPs in MM.

In vitro and ex vivo anti-myeloma effects of nanocomposite As4S4/ZnS/Fe3O4.

Nanoparticles in medicine can integrate actively targeted imaging agents and drug delivery vehicles, and combining multiple types of therapeutics in a single particle has numerous advantages, especially in multiple myeloma. MM is an incurable hematological disorder characterized by clonal proliferation of plasma cells in the bone marrow. In this study, we evaluated the anti-myeloma activity of 3 nanocomposites (3NPs): As4S4/ZnS/Fe3O4 (1:4:1), As4S4/ZnS/Fe3O4 with folic acid (FA), and As4S4/ZnS/Fe3O4 with FA and albumin with reduced survival MM cell lines and primary MM samples by each of 3NP. Cytotoxic effects of 3NPs were associated with caspase- and mitochondria-dependent apoptosis induction and reduced c-Myc expression. Modulation of cell cycle regulators, such as p-ATM/ATM and p-ATR/ATR, and increases in p-Chk2, cyclin B1, and histones were accompanied by G2/M arrest triggered by 3NPs. In addition, 3NPs activated several myeloma-related signaling, including JNK1/2/3, ERK1/2 and mTOR. To overcome BM microenvironment-mediated drug resistance, nanocomposites retained its anti-MM activity in the presence of stroma. 3NPs significantly decreased the stem cell-like side population in MM cells, even in the context of stroma. We observed strong synergistic effects of 3NPs combined with lenalidomide, pomalidomide, or melphalan, suggesting the potential of these combinations for future clinical studies.

A Structural Analysis of the Angucycline-Like Antibiotic Auricin from Streptomyces lavendulae Subsp. Lavendulae CCM 3239 Revealed Its High Similarity to Griseusins.

We previously identified the aur1 gene cluster in Streptomyces lavendulae subsp. lavendulae CCM 3239 (formerly Streptomyces aureofaciens CCM 3239), which is responsible for the production of the angucycline-like antibiotic auricin (1). Preliminary characterization of 1 revealed that it possesses an aminodeoxyhexose d-forosamine and is active against Gram-positive bacteria. Here we determined the structure of 1, finding that it possesses intriguing structural features, which distinguish it from other known angucyclines. In addition to d-forosamine, compound 1 also contains a unique, highly oxygenated aglycone similar to those of spiroketal pyranonaphthoquinones griseusins. Like several other griseusins, 1 also undergoes methanolysis and displays modest cytotoxicity against several human tumor cell lines. Moreover, the central core of the aur1 cluster is highly similar to the partial gris gene cluster responsible for the biosynthesis of griseusin A and B in both the nature of the encoded proteins and the gene organization.

Effects of short-term Pilates exercise on selected blood parameters.

The aim of our prospective, interventional, pre-post, single arm study was to supplement the lack of knowledge of the effect of short-term Pilates intervention on selected blood parameters of healthy women. Female volunteers were recruited for 2-weeks Pilates intervention. Blood has been collected and anthropometric parameters were measured before and after exercise period (EP). Plasma insulin, cortisol, and dehydroepiandrosterone sulphate levels, erythrocyte antioxidant activity, glutathione levels, NK cytotoxicity and plasma cytokines were analysed. We found a decrease in erythrocyte antioxidant enzymes SOD and GPx activity; GSH levels; in the pro-inflammatory chemokine MCP-1 and trend to reduction in MIP-1ß, PDGF and VEGF levels in plasma. NK cell cytotoxic activity increased after Pilates EP in the percentage of specific lysis at 25:1 effector: target (E:T) ratio and the same trend was observed at all E:T ratios as well as in the amount of lytic units per 107 cells. Our findings show that Pilates exercise may improve NK cell immune response and inflammatory milieu in plasma of healthy women.

Sulforaphane-induced apoptosis involves the type 1 IP3 receptor.

In this study we show that anti-tumor effect of sulforaphane (SFN) is partially realized through the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1). This effect was verified in vitro on three different stable cell lines and also in vivo on the model of nude mice with developed tumors. Early response (6 hours) of A2780 ovarian carcinoma cells to SFN treatment involves generation of mitochondrial ROS and increased transcription of NRF2 and its downstream regulated genes including heme oxygenase 1, NAD(P)H:quinine oxidoreductase 1, and KLF9. Prolonged SFN treatment (24 hours) upregulated expression of NRF2 and IP3R1. SFN induces a time-dependent phosphorylation wave of HSP27. Use of IP3R inhibitor Xestospongin C (Xest) attenuates both SFN-induced apoptosis and the level of NRF2 protein expression. In addition, Xest partially attenuates anti-tumor effect of SFN in vivo. SFN-induced apoptosis is completely inhibited by silencing of IP3R1 gene but only partially blocked by silencing of NRF2; silencing of IP3R2 and IP3R3 had no effect on these cells. Xest inhibitor does not significantly modify SFN-induced increase in the rapid activity of ARE and AP1 responsive elements. We found that Xest effectively reverses the SFN-dependent increase of nuclear content and decrease of reticular calcium content. In addition, immunofluorescent staining with IP3R1 antibody revealed that SFN treatment induces translocation of IP3R1 to the nucleus. Our results clearly show that IP3R1 is involved in SFN-induced apoptosis through the depletion of reticular calcium and modulation of transcription factors through nuclear calcium up-regulation.

Pro-apoptotic effect of new quinolone 7- ethyl 9-ethyl-6-oxo-6,9-dihydro[1,2,5]selenadiazolo [3,4-h]quinoline-7-carboxylate on cervical cancer cell line HeLa alone/with UVA irradiation.

7- ethyl 9-ethyl-6-oxo-6,9-dihydro[1,2,5]selenadiazolo [3,4-h]quinoline-7-carboxylate (E2h) is a new synthetically prepared quinolone derivative, which in our primary study showed cytotoxic effects towards tumor cells. The aim of the present study was to examine the antiproliferative and apoptosis inducing activities of E2h towards human cervical cancer cell line HeLa with/without the presence of UVA irradiation. Further, the molecular mechanism involved in E2h-induced apoptosis in HeLa cells was investigated. Our results showed that both non-photoactivated and photoactivated E2h caused morphological changes and inhibited the cell growth of HeLa cells in a time- and dose-dependent manner. Irradiation increased the sensitivity of HeLa cells to E2h. Quinolone induced S and G2/M arrest and apoptosis in HeLa cells, as characterized by DNA fragmentation and flow cytometry. In addition, E2h elevated the level of reactive oxygen species and activated caspases 3. In conclusions, E2h alone/in combination with UVA irradiation induced apoptosis in HeLa cells through the ROS-mitochondrial/caspase 3-dependent pathway.

Sulforaphane reduces molecular response to hypoxia in ovarian tumor cells independently of their resistance to chemotherapy.

One of the recently emerging anticancer strategies is the use of natural dietary compounds, such as sulforaphane, a cancer-chemopreventive isothiocyanate found in broccoli. Based on the growing evidence, sulforaphane acts through molecular mechanisms that interfere with multiple oncogenic pathways in diverse tumor cell types. Herein, we investigated the anticancer effects of bioavailable concentrations of sulforaphane in ovarian carcinoma cell line A2780 and its two derivatives, adriamycin-resistant A2780/ADR and cisplatin-resistant A2780/CP cell lines. Since tumor microenvironment is characterized by reduced oxygenation that induces aggressive tumor phenotype (such as increased invasiveness and resistance to chemotherapy), we evaluated the effects of sulforaphane in ovarian cancer cells exposed to hypoxia (2% O2). Using the cell-based reporter assay, we identified several oncogenic pathways modulated by sulforaphane in hypoxia by activating anticancer responses (p53, ARE, IRF-1, Pax-6 and XRE) and suppressing responses supporting tumor progression (AP-1 and HIF-1). We further showed that sulforaphane decreases the level of HIF-1α protein without affecting its transcription and stability. It can also diminish transcription and protein level of the HIF-1 target, CA IX, which protects tumor cells from hypoxia-induced pH imbalance and facilitates their migration/invasion. Accordingly, sulforaphane treatment leads to diminished pH regulation and reduced migration of ovarian carcinoma cells. These effects occur in all three ovarian cell lines suggesting that sulforaphane can overcome the chemoresistance of cancer cells. This offers a path potentially exploitable in sensitizing resistant cancer cells to therapy, and opens a window for the combined treatments of sulforaphane either with conventional chemotherapy, natural compounds, or with other small molecules.

Modulation of cisplatin sensitivity in human ovarian carcinoma A2780 and SKOV3 cell lines by sulforaphane.

Cisplatin resistance is one of the major obstacles in the treatment of ovarian cancer. In an effort to look for new possibilities of how to overcome this difficulty, we studied the mechanisms of the interactions between sulforaphane (SFN) and cisplatin (cisPt) in combined treatment of human ovarian carcinoma A2780 and SKOV3 cell lines. Synergy (A2780) and antagonism (SKOV3) found in MTT assay was confirmed by apoptosis. While SFN significantly potentiated cisPt-induced DNA damage in A2780 cells, it protected SKOV3 cells against cisPt-crosslinking. We revealed a less efficient Nrf-2 pathway inducibility by SFN in A2780 compared to SKOV3 cells, when activation of the Nrf-2 pathway incites its protectivity against cisPt. Thus, different activation of the Nrf-2 pathway may explain the dual effects of SFN.

Isoproterenol accelerates apoptosis through the over-expression of the sodium/calcium exchanger in HeLa cells.

Apoptosis induction causes over-expression of the Na+/Ca2+ exchanger of type 1 (NCX1) in the HeLa cell line. During induction of apoptosis and in the presence of isoproterenol hydrochloride (I; ß-adrenergic agonist), increase in the NCX1 is even more pronounced. Anti-apoptotic Bcl-2 mRNA and protein is markedly reduced during apoptosis and in the presence of I, which causes a rapid increase in the Bax/Bcl-2 ratio. During apoptosis induction by apoptosis inducing kit (A), both with and without I, the active form of caspase-3, which is the executive enzyme in apoptosis, becomes visible on Western blots. Silencing NCX1 resulted in the reversal of the Bax/Bcl-2 ratio, it prevented a decrease in mitochondrial membrane potential compared to the AI group and it decreased the level of AI-induced apoptosis in HeLa cells. Based on the experiments with single apoptotic inducers camptothecin, cycloheximide and dexamethasone, it might be proposed that potentiated apoptotic effect in I-treated cells is due to the inhibition of nuclear topoisomerase. As illustrated in immunofluorescence and Western blot analysis, calnexin increased significantly during induction of the apoptosis in the presence of I. In addition, further decrease in sarco/endoplasmic ATPase 2 (SERCA2), decrease in reticular calcium and mitochondrial membrane potential was observed, which suggests development of the endoplasmic reticulum (ER) stress. Based on these results, we propose that I further enhanced NCX1 expression in apoptotic cells through the development of ER stress.

Increased production of IL-6 and IL-17 in lipopolysaccharide-stimulated peripheral mononuclears from patients with rheumatoid arthritis.

TLR4-mediated inflammatory responses are important for innate immune functions, thus their alterations may participate in the pathogenesis of rheumatoid arthritis (RA). Cortisol is one of the most potent immunomodulatory hormones involved in control of inflammation. In this study, we analyzed TLR4-mediated responses and cortisol effects on the process in peripheral blood mononuclear cells (PBMC) from RA patients. Lipopolysaccharide-stimulated PBMC from 23 female patients and 15 healthy controls were cultured in the presence or absence of cortisol (1 µM) for 24 h. A panel of 17 inflammatory cytokines was analyzed in the cell culture supernatants. Higher (p < 0.05) concentrations of IL-6, IL-17 and MCP-1 were found in lipopolysaccharide-stimulated PBMC from RA patients compared to controls. After normalization of stimulated cytokine secretion to unstimulated cells, a significantly higher (p < 0.05) IL-6 and G-CSF production was found in RA PBMC. Cortisol induced stronger (p < 0.05) suppression of lipopolysaccharide-stimulated secretion of IL-1ß, IL-6, IL-17 and G-CSF in RA group compared to controls. The observed higher production of the key inflammatory cytokines by RA PBMC to lipopolysaccharide stimulation supports involvement of TLR4-mediated processes in RA pathogenesis. The higher sensitivity of LPS-stimulated RA PBMC to immunosuppressive effects of cortisol may reflect adaptive processes to chronic inflammation.

Immunophenotypic profile of nucleated erythroid progenitors during maturation in regenerating bone marrow.

This study introduces an in-depth flow cytometric method for the analysis of nucleated erythroid progenitors during bone marrow regeneration. Initial immunophenotypic analysis with the conventional erythroid-associated markers CD36, CD71 and CD235a was supplemented with the analysis of additional markers, including CD105, CD117, CD45, CD38 and cell-scattered light characteristics. Our data show that the expression of CD105 and CD117 is critical for the distinction between four phenotypically different developmental stages of nucleated erythroid progenitors: pro-erythroblasts, basophilic erythroblasts, polychromatophilic erythroblasts and orthochromatophilic erythroblasts. CD105 antigen expression was specifically associated with pro-erythroblasts and basophilic erythroblasts, whereas CD117 was expressed at the earliest pro-erythroblast stage. Both antigens were progressively lost throughout the course of differentiation. These data allow for the identification of aberrant erythroid development in acute erythroid leukemia or myelodysplastic syndrome.

MGN-3 arabinoxylan rice bran modulates innate immunity in multiple myeloma patients.

Dendritic cells (DCs) and natural killer (NK) cells are central components of innate immunity for controlling tumor growth. The therapeutic effects of certain anti-myeloma drugs are partially mediated by targeting the innate immune response. In addition, novel types of natural compounds have been developed that efficiently modulate the activity of both the cellular and humoral compartments of immunity. MGN-3 is known as an activator of natural killer cells, inducer of apoptosis and cytokine production, and modulator of dendritic cell maturation and differentiation in vitro. We have performed a randomized, placebo-controlled study to examine the effects of MGN-3 on innate immune system parameters in 48 multiple myeloma patients. We performed immunophenotypic analysis of peripheral blood samples, determined NK cell activity, and assessed the cytokine profiles of plasma before and during 3 months of treatment. The results demonstrate a clear increase in NK activity in MGN-3-treated patients compared to the placebo group, an increased level of myeloid DCs in peripheral blood, and augmented concentrations of T helper cell type 1-related cytokines. The present study suggests that MGN-3 may represent an immunologically relevant product for activating innate immunity in multiple myeloma patients and warrants further testing to demonstrate clinical efficacy.

Potentiation of anticancer drugs: effects of pentoxifylline on neoplastic cells.

The drug efflux activity of P-glycoprotein (P-gp, a product of the mdr1 gene, ABCB1 member of ABC transporter family) represents a mechanism by which tumor cells escape death induced by chemotherapeutics. In this study, we investigated the mechanisms involved in the effects of pentoxifylline (PTX) on P-gp-mediated multidrug resistance (MDR) in mouse leukemia L1210/VCR cells. Parental sensitive mouse leukemia cells L1210, and multidrug-resistant cells, L1210/VCR, which are characterized by the overexpression of P-gp, were used as experimental models. The cells were exposed to 100 µmol/L PTX in the presence or absence of 1.2 µmol/L vincristine (VCR). Western blot analysis indicated a downregulation of P-gp protein expression when multidrug-resistant L1210/VCR cells were exposed to PTX. The effects of PTX on the sensitization of L1210/VCR cells to VCR correlate with the stimulation of apoptosis detected by Annexin V/propidium iodide apoptosis necrosis kit and proteolytic activation of both caspase-3 and caspase-9 monitored by Western blot analysis. Higher release of matrix metalloproteinases (MMPs), especially MMP-2, which could be attenuated by PTX, was found in L1210/VCR than in L1210 cells by gelatin zymography in electrophoretic gel. Exposure of resistant cells to PTX increased the content of phosphorylated Akt kinase. In contrast, the presence of VCR eliminated the effects of PTX on Akt kinase phosphorylation. Taken together, we conclude that PTX induces the sensitization of multidrug-resistant cells to VCR via downregulation of P-gp, stimulation of apoptosis and reduction of MMPs released from drug-resistant L1210/VCR cells. These facts bring new insights into the mechanisms of PTX action on cancer cells.

P-glycoprotein depresses cisplatin sensitivity in L1210 cells by inhibiting cisplatin-induced caspase-3 activation.

Multidrug resistance (MDR) is a phenomenon in which cells become resistant to cytostatic drugs and other substances with diverse chemical structures and cytotoxicity mechanisms. The most often observed molecular mechanism for MDR includes high levels of P-glycoprotein (P-gp)--an ABCB1 member of the ABC drug transporter family. Overexpression of P-gp in neoplastic tissue is an obstacle to chemotherapeutic treatment. Herein, we were focused on differences in apoptosis induced by cisplatin (no substrate for P-gp) between P-gp-positive and P-gp-negative L1210 cells. P-gp-positive cells were obtained by either L1210 cell adaptation to vincristine (R) or L1210 cell transfection with the human gene for P-gp (T) and compared with parental L1210 cells (S). R and T cells were more resistant to CisPt than S cells. R and T cell resistance to CisPt-induced apoptosis could not be reversed by verapamil (a well-known P-gp inhibitor), which excludes P-gp transport activity as a cause of CisPt resistance. CisPt induced a more pronounced entry into apoptosis in S than R and T cells, which was measured using the annexin-V/propidium iodide apoptosis kit. CisPt induced more pronounced caspase-3 activation in S than R and T cells. CisPt did not induce changes in the P-gp protein level for R and T cells. While similar levels of Bax and Bcl-2 proteins were observed in P-gp-negative and P-gp-positive cells, CisPt induced a more significant decrease in Bcl-2 levels for S cells than P-gp-positive cells. Expression of p53 and its molecular chaperone Hsp90 were more pronounced in R and T than S cells. Moreover, CisPt enhanced the upregulation of p53 and Hsp90 in R and T cells to a higher degree than S cells. Apoptosis was shown to be the prevalent mode of cell death in S, R and T cells by the typical DNA fragmentation and cell ultrastructure changes. All of the above findings indicate that P-gp, independent of its drug efflux activity, induced changes in cell regulatory pathways that confer a partial loss of cisplatin sensitivity.

HDAC inhibitors potentiate the apoptotic effect of enzastaurin in lymphoma cells.

Enzastaurin is an investigational PKCß inhibitor that has growth inhibitory and pro-apoptotic effects in both B and T-cell lymphomas. We investigated the cytotoxicity and mechanisms of cell death of the combination of enzastaurin and low concentrations of histone deacetylase (HDAC) inhibitors in B-cell and T-cell lymphoma cell lines and primary lymphoma/leukemia cells. Combined enzastaurin/suberoylanilide hydroxamic acid treatment synergistically induced apoptosis in diffuse large B-cell lymphoma and T-cell lymphoma cell lines, and primary lymphoma/leukemia samples. Similarly, combined treatment of B-cell-like lymphoma cells with enzastaurin and two different HDAC inhibitors, valproic acid and (2E,4E)-6-(4-chlorophenylsulfanyl)-2,4-hexadienoic acid hydroxyamide synergistically induced apoptosis, suggesting the synergy is generalizable to other HDAC inhibitors. Our data indicate that enzastaurin/HDAC inhibitors therapy can synergistically inhibit growth and induce apoptosis in lymphoid malignancies and may be an effective therapeutic strategy. Potential mechanisms including enzastaurin mediated inhibition of HDAC inhibitor-induced compensatory survival pathways are discussed.

Anti-tumor activity and signaling events triggered by the isothiocyanates, sulforaphane and phenethyl isothiocyanate, in multiple myeloma.

BACKGROUND: Isothiocyanates, a family of phytochemicals found in cruciferous vegetables, have cytotoxic effects against several types of tumor cells. Multiple myeloma is a fatal disease characterized by clonal proliferation of plasma cells in the bone marrow. The growing body of preclinical information on the anti-cancer activity of isothiocyanates led us to investigate their anti-myeloma properties. DESIGN AND METHODS: We evaluated the anti-myeloma activity of the isothiocyanates, sulforaphane and phenethyl isothiocyanate, on a panel of human myeloma cell lines as well as primary myeloma tumor cells. Cell viability, apoptosis, cell cycle alterations and cell proliferation were then analyzed in vitro and in a xenograft mouse model in vivo. The molecular sequelae of isothiocyanate treatment in multiple myeloma cells were evaluated by multiplex analyses using bead arrays and western blotting. RESULTS: We observed that sulforaphane and phenylethyl isothiocyanate have activity against myeloma cell lines and patients' myeloma cells both in vitro and in vivo using a myeloma xenograft mouse model. Isothiocyanates induced apoptotic death of myeloma cells; depletion of mitochondrial membrane potential; cleavage of PARP and caspases-3 and -9; as well as down-regulation of anti-apoptotic proteins including Mcl-1, X-IAP, c-IAP and survivin. Isothiocyanates induced G(2)/M cell cycle arrest accompanied by mitotic phosphorylation of histone H3. Multiplex analysis of phosphorylation of diverse components of signaling cascades revealed changes in MAPK activation; increased phosphorylation of c-jun and HSP27; as well as changes in the phosphorylation of Akt, and GSK3α/ß and p53. Isothiocyanates suppressed proliferation of myeloma cells alone and when co-cultured with HS-5 stromal cells. Sulforaphane and phenylethyl isothiocyanate enhanced the in vitro anti-myeloma activity of several conventional and novel therapies used in multiple myeloma. CONCLUSIONS: Our study shows that isothiocyanates have potent anti-myeloma activities and may enhance the activity of other anti-multiple myeloma agents. These results indicate that isothiocyanates may have therapeutic potential in multiple myeloma and provide the preclinical framework for future clinical studies of isothiocyanates in multiple myeloma.

Lenalidomide targets clonogenic side population in multiple myeloma: pathophysiologic and clinical implications.

Recurrence of multiple myeloma (MM) after therapy suggests the presence of tumor-initiating subpopulations. In our study, we performed flow cytometry-based Hoechst 33342 staining to evaluate the existence of a MM population with stem-like features known as side population (SP) cells. SP cells exhibit substantial heterogeneity in MM cell lines and primary MM cells; express CD138 antigen in MM cell lines; display higher mRNA expression and functional activity of ABCG2 transporter; and have a higher proliferation index compared with non-SP cells. We observed evidence for clonogenic potential of SP cells, as well as the ability of SP cells to regenerate original population. Moreover, SP cells revealed higher tumorigenicity compared with non-SP cells. Importantly, lenalidomide decreased the percentage and clonogenicity of SP cells, and also induced phosphorylation changes in Akt, GSK-3α/ß, MEK1, c-Jun, p53, and p70S6K in SP cells. Adherence to bone marrow stromal cells (BMSCs) increased the percentage, viability, and proliferation potential of SP cells. Lenalidomide and thalidomide abrogated this stimulatory effect of BMSCs and significantly decreased the percentage of SP cells. Our studies demonstrate a novel mechanism of action for lenalidomide, namely targeting SP fraction, providing the framework for new therapeutic strategies targeting subpopulations of MM cells including presumptive stem cells.

The presence of P-glycoprotein in L1210 cells directly induces down-regulation of cell surface saccharide targets of concanavalin A.

Overexpression of P-glycoprotein (P-gp), a plasma membrane drug transporter (ABCB1, a member of the ABC transporter family), is the most prevalent cause of multidrug resistance in cancer tissues. Lectin concanavalin A (ConA) induces massive cell death of L1210 leukemia cells (S). Cell sublines of L1210 in which P-gp overexpression was induced by selection with vincristine (R) or by stable transfection with a plasmid encoding full-length human P-gp (T) were less sensitive to ConA. Both P-gp-positive cell lines exhibited typical P-gp-mediated multidrug resistance. Resistance of R and T cells to ConA was associated with lower binding of ConA as compared to S cells when analysed by the following methods: (i) SDS PAGE and electroblotting of proteins in the crude membrane fraction followed by detection with biotinylated ConA and avidin-peroxidase, and (ii) fluorescent cytometry or confocal microscopy of the intact cells with surfaces labeled by FITC-ConA. These data indicated that the presence of P-glycoprotein in L1210 cells independently of the mode of its expression induced down-regulation of cell surface saccharide targets of ConA. Therefore, this feature may be considered as a secondary cellular response to P-glycoprotein expression.

Arsenic in cancer treatment: challenges for application of realgar nanoparticles (a minireview).

While intensive efforts have been made for the treatment of cancer, this disease is still the second leading cause of death in many countries. Metastatic breast cancer, late-stage colon cancer, malignant melanoma, multiple myeloma, and other forms of cancer are still essentially incurable in most cases. Recent advances in genomic technologies have permitted the simultaneous evaluation of DNA sequence-based alterations together with copy number gains and losses. The requirement for a multi-targeting approach is the common theme that emerges from these studies. Therefore, the combination of new targeted biological and cytotoxic agents is currently under investigation in multimodal treatment regimens. Similarly, a combinational principle is applied in traditional Chinese medicine, as formulas consist of several types of medicinal herbs or minerals, in which one represents the principal component, and the others serve as adjuvant ones that assist the effects, or facilitate the delivery, of the principal component. In Western medicine, approximately 60 different arsenic preparations have been developed and used in pharmacological history. In traditional Chinese medicines, different forms of mineral arsenicals (orpiment-As(2)S(3), realgar-As(4)S(4), and arsenolite-arsenic trioxide, As(2)O(3)) are used, and realgar alone is included in 22 oral remedies that are recognized by the Chinese Pharmacopeia Committee (2005). It is known that a significant portion of some forms of mineral arsenicals is poorly absorbed into the body, and would be unavailable to cause systemic damage. This review primary focuses on the application of arsenic sulfide (realgar) for treatment of various forms of cancer in vitro and in vivo.

Type 2 IP(3) receptors are involved in uranyl acetate induced apoptosis in HEK 293 cells.

Calcium released from endoplasmic reticulum through special calcium release channels - inositol 1,4,5-trisphosphate receptors (IP(3)Rs) and ryanodine receptors (RyRs) - serves as a main source of cytosolic calcium signaling in the majority of cell types in physiological state and also in pathological situations. In this work, we studied whether IP(3)Rs can be involved in uranyl acetate induced nephrotoxicity. Using human embryonic kidney cell line (HEK293) as an experimental model we have found that uranyl acetate (5 and 50microM) up-regulates both, mRNA and protein levels of the type 1 and type 2 IP(3) receptors in HEK293 cells. This increase was associated with elevated expression of proapoptotic factors Bax and Caspase 3 and also by higher extent of apoptosis. Vice versa, induction of apoptosis resulted in increased mRNA levels of IP(3)R2 and also elevated levels of apoptotic markers. Therefore we propose that enhanced expression of the type 2 IP(3)Rs can at least partially contribute to increased levels of apoptosis due to uranyl acetate treatment.