Compact Cell Settlers for Perfusion Cultures of Microbial (and Mammalian) Cells.

As microbial secretory expression systems have become well developed for microbial yeast cells, such as Saccharomyces cerevisiae and Pichia pastoris, it is advantageous to develop high cell density continuous perfusion cultures of microbial yeast cells to retain the live and productive yeast cells inside the perfusion bioreactor while removing the dead cells and cell debris along with the secreted product protein in the harvest stream. While the previously demonstrated inclined or lamellar settlers can be used for such perfusion bioreactors for microbial cells, the size and footprint requirements of such inefficiently scaled up devices can be quite large in comparison to the bioreactor size. Faced with this constraint, we have now developed novel, patent-pending compact cell settlers that can be used more efficiently with microbial perfusion bioreactors to achieve high cell densities and bioreactor productivities. Reproducible results from numerous month-long perfusion culture experiments using these devices attached to the 5 L perfusion bioreactor demonstrate very high cell densities due to substantial sedimentation of the larger live yeast cells which are returned to the bioreactor, while the harvest stream from the top of these cell settlers is a significantly clarified liquid, containing less than 30% and more typically less than 10% of the bioreactor cell concentration. Size of cells in the harvest is smaller than that of the cells in the bioreactor. Accumulated protein collected from the harvest and rate of protein accumulation is significantly (> 6x) higher than the protein produced in repeated fed-batch cultures over the same culture duration. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:913-922, 2017.

In vitro and in vivo effects of free and chalcones-loaded nanoemulsions: insights and challenges in targeted cancer chemotherapies.

Several obstacles are encountered in conventional chemotherapy, such as drug toxicity and poor stability. Nanotechnology is envisioned as a strategy to overcome these effects and to improve anticancer therapy. Nanoemulsions comprise submicron emulsions composed of biocompatible lipids, and present a large surface area revealing interesting physical properties. Chalcones are flavonoid precursors, and have been studied as cytotoxic drugs for leukemia cells that induce cell death by different apoptosis pathways. In this study, we encapsulated chalcones in a nanoemulsion and compared their effect with the respective free compounds in leukemia and in non-tumoral cell lines, as well as in an in vivo model. Free and loaded-nanoemulsion chalcones induced a similar anti-leukemic effect. Free chalcones induced higher toxicity in VERO cells than chalcones-loaded nanoemulsions. Similar results were observed in vivo. Free chalcones induced a reduction in weight gain and liver injuries, evidenced by oxidative stress, as well as an inflammatory response. Considering the high toxicity and the side effects induced generally by all cancer chemotherapies, nanotechnology provides some options for improving patients' life quality and/or increasing survival rates.

Anti-NeuGcGM3 antibodies, actively elicited by idiotypic vaccination in nonsmall cell lung cancer patients, induce tumor cell death by an oncosis-like mechanism.

1E10 is a murine anti-idiotypic mAb specific for an idiotypic mAb that reacts with NeuGc-containing gangliosides, sulfatides, and Ags expressed in some human tumors. In melanoma, breast, and lung cancer patients, this anti-idiotypic Ab was able to induce a specific Ab response against N-glycosylated gangliosides, attractive targets for cancer immunotherapy as these glycolipids are not naturally expressed in humans. A clinical study with nonsmall cell lung cancer patients showed encouraging clinical benefits. Immunological studies performed in 20 of these patients suggested a correlation between the induction of Abs against NeuGcGM3 and longer survival times. The induced anti-NeuGcGM3 Abs recognized and directly killed tumor cells expressing the Ag, by a mechanism independent of complement activation. In the present work, we show that this cytotoxicity differs from apoptosis because it is temperature independent, no chromatin condensation or caspase 3 induction are detected, and the DNA fragmentation induced has a different pattern than the one characteristic for apoptosis. It is a very quick process and involves cytosqeleton reorganization. The Abs induce cellular swelling and the formation of big membrane lesions that allow the leakage of cytoplasm and the loss of the cell membrane integrity. All of these characteristics resemble a process of oncotic necrosis. To our knowledge, this is the first report of the active induction in cancer patients of NeuGcGM3-specific Abs able to induce complement independent oncotic necrosis to tumor cells. These results contribute to reinforcing the therapeutic potential of anti-idiotypic vaccines and the importance of NeuGcGM3 ganglioside as antitumor target.

Induction of apoptosis and cell cycle arrest in L-1210 murine lymphoblastic leukaemia cells by (2E)-3-(2-naphthyl)-1-(3'-methoxy-4'-hydroxy-phenyl)-2-propen-1-one.

OBJECTIVES: New compounds with biological targets and less cytotoxicity to normal cells are necessary for cancer therapy. In this work ten synthetic chalcones derived from 2-naphtaldehyde were evaluated for their cytotoxic effect in murine acute lymphoblastic leukemia cells L-1210. METHODS: A series of ten chalcones derived from 2-naphtaldehyde and corresponding acetophenones were prepared by aldolic condensation, using methanol as solvent under basic conditions, at room temperature for 24 h. The cell viability was determined by MTT colorimeter method. The cell cycle phase analysis was carried out by flow cytometry after propidium iodide staining. The apoptosis induction was assessed by exposure to phosphatidylserine (ANNEXIN V-FITC). Cytometric analysis was performed to evaluate the expression of p53, Bcl-2 and Bax protein. The caspase-3 expression was studied by immunoblotting analysis. KEY FINDINGS: A preliminary screening of a series of ten chalcones derived from 2-naphtaldehyde showed that chalcone 8, (2E)-3-(2-naphtyl)-1-(3'-methoxy-4'-hydroxy-phenyl)-2-propen-1-one, had the highest cytotoxic effect (IC50 of 54 microM), but not in normal human lymphocytes. To better understand the cytotoxic mechanism of chalcone 8, its effect on cell cycle and apoptosis was assessed. Our results showed that chalcone 8 caused cell cycle arrest in the G2/M phase and a significant increase in the proportion of cells in the subG0/G1 phase. Our results also demonstrated that chalcone 8 promoted a modification in Bax:Bcl-2 ratio and increased p53 expression and caspase-3 activation. CONCLUSIONS: The studied chalcone 8 has cytotoxic effect against L-1210 lymphoblastic leukaemic cells, and this effect is associated with increase of p-53 and Bax expression.

Ester derivatives of gallic acid with potential toxicity toward L1210 leukemia cells.

Gallic acid and gallates with the same number of hydroxyl groups and varying the length of the side carbon chain, with respective lipophilicity being defined through the ClogP values, were examined for their ability to induce apoptosis (through the DNA ladder fragmentation pattern), mitochondrial and cytoplasmic GSH depletion and NF-kappaB activation in murine lymphoblastic L1210 leukemia cells. A relationship between cytotoxic effect and a limited degree of lipophilicity was observed.

Structure-activity relationship studies of new acronine analogues as suggested by molecular descriptors.

This work describes the results of an investigation on the structure-activity relationships of a series of acronine (CAS 7008-42-6) analogues which possess cytotoxic and antitumor activity. The results were obtained employing a commercially available software, which correlates structure and activity through calculations with different descriptors. The best results, obtained with electrostatic descriptors, led to propose new structures which present higher calculated activity than that of acronine.

Brasilibactin A, a cytotoxic compound from actinomycete Nocardia brasiliensis.

A new cytotoxic compound, brasilibactin A (1), has been isolated from the actinomycete Nocardia brasiliensis IFM 0995, and the structure was elucidated on the basis of spectroscopic data and chemical means.

Killing of lymphoblastic leukemia cells by nitric oxide and taxol: involvement of NF-kappaB activity.

Nitric oxide (NO) and taxol are cytotoxic towards leukemia and tumor cells and interfere with the transcription factor NF-kappaB activity. NO and taxol inhibited NF-kappaB activity and were cytotoxic to human and murine leukemia cells, but at a different magnitude (30% cell killing and 80% inhibition of NF-kappaB). Sub-effective concentrations of SNAP and taxol synergized in killing L-1210 cells but either alone or in combination completely inhibited NF-kappaB. Pyrrolidine dithiocarbamate (PDTC) was cytotoxic on its own and inhibited NF-kappaB activity. It potentiated NO and taxol killing but again there was no direct relationship between inhibition of NF-kappaB and cell killing. Neither NO nor taxol cytotoxicity was related to the cytoskeleton. Our results show that NO, taxol and PDTC induced apoptosis and NF-kappaB inhibition in leukemic cells but their cytotoxicity either alone or in combination, does not seem to be dependent on the inhibition of NF-KB activity.

Pacovatinins A-C, new labdane diterpenoids from the seeds of Renealmia exaltata.

Three new labdane diterpenoids, pacovatinins A-C (1-3), were isolated from seeds of the Brazilian medicinal plant Renealmia exaltata ("Pacová-catinga"), and their structures including absolute configurations were elucidated by spectroscopic data and a modified Mosher method.

Collateral methotrexate resistance in cisplatin-selected murine leukemia cells.

Resistance to anticancer drugs is a major cause of failure of many therapeutic protocols. A variety of mechanisms have been proposed to explain this phenomenon. The exact mechanism depends upon the drug of interest as well as the tumor type treated. While studying a cell line selected for its resistance to cisplatin we noted that the cells expressed a > 25,000-fold collateral resistance to methotrexate. Given the magnitude of this resistance we elected to investigate this intriguing collateral resistance. From a series of investigations we have identified an alteration in a membrane protein of the resistant cell as compared to the sensitive cells that could be the primary mechanism of resistance. Our studies reviewed here indicate decreased tyrosine phosphorylation of a protein (molecular mass = 66) in the resistant cells, which results in little or no transfer of methotrexate from the medium into the cell. Since this is a relatively novel function for tyrosine phosphorylation, this information may provide insight into possible pharmacological approaches to modify therapeutic regimens by analyzing the status of this protein in tumor samples for a better survival of the cancer patients.

Collateral methotrexate resistance in cisplatin-selected murine leukemia cells

Resistance to anticancer drugs is a major cause of failure of many therapeutic protocols. A variety of mechanisms have been proposed to explain this phenomenon. The exact mechanism depends upon the drug of interest as well as the tumor type treated. While studying a cell line selected for its resistance to cisplatin we noted that the cells expressed a >25,000-fold collateral resistance to methotrexate. Given the magnitude of this resistance we elected to investigate this intriguing collateral resistance. From a series of investigations we have identified an alteration in a membrane protein of the resistant cell as compared to the sensitive cells that could be the primary mechanism of resistance. Our studies reviewed here indicate decreased tyrosine phosphorylation of a protein (molecular mass = 66) in the resistant cells, which results in little or no transfer of methotrexate from the medium into the cell. Since this is a relatively novel function for tyrosine phosphorylation, this information may provide insight into possible pharmacological approaches to modify therapeutic regimens by analyzing the status of this protein in tumor samples for a better survival of the cancer patients

Analogues and prodrugs, permanent useful alternatives to improve the effectiveness of natural anticancer compounds: Enhanced activity of slightly soluble salts of olivacine in L1210 leukemia

Several derivatives of well-known natural anticancer drugs have been synthesized and will continue to be, to overcome their delivering problems, or effectiveness. Characteristics such as poor solubility, metabolic inactivation, resistance development, rapid clearance or short half-life, adverse side effects like nausea, alopecia, anorexia are common undesirable limitations to their clinical use. Drug toxicity to less sensitive tumors as those in liver or brain is another aimed goal. Recent efforts to reverse undesirable physicochemical properties of well-established natural anticancer compounds are focused. Improved antitumor action of olivacine in L(1210) leukemia with slightly soluble halides with increased life span as well as "cured" animals was observed.

Oxidative stress induces activation of a cytosolic protein responsible for control of iron uptake.

A cytosolic protein, named iron-responsive element-binding protein (IRE-BP), is sensitive to cellular iron concentration. At low cytosolic iron level, IRE-BP is activated and binds to stem-loop untranslated regions (IRE regions) of transferrin and ferritin mRNAs, activating and inhibiting their translations, respectively. This concerted mechanism permits a fine control of iron homeostasis in the cell. The activity of IRE-BP can be measured by its binding to IRE regions, using a protein band-shift electrophoretic assay. Damage to cells by oxidative stress is known to be mediated by iron. We observed that IRE-BP is rapidly activated by exposure of V79 Chinese hamster ovary cells to H2O2. However, if cell extracts are exposed to H2O2 IRE-BP activation is not observed. Therefore, the activation is not a direct consequence of the H2O2 attack to IRE-BP. The in vivo IRE-BP-activation by H2O2 is not prevented by hydroxyl radical scavengers or by the iron chelator 1,10-phenanthroline, indicating that Fenton reaction is not involved in the process. In fact, simultaneous exposure of cells to H2O2 and 1,10-phenanthroline produces an even stronger activation than exposure to H2O2 alone. The interpretation of the mechanism of IRE-BP activation by oxidative stress is hampered by the fact that the mechanism of IRE-BP modulation by cytosolic iron has not been established. It has been recently shown that the iron-sulfur cluster in IRE-BP must be completely disassembled in order for activation to occur and that this is triggered by low iron in the cell. It is likely that IRE-BP senses Fe(II) and that its oxidation to Fe(III) by H2O2 or chelation by 1,10-phenanthroline set up a program for increasing iron uptake. The physiological consequences of this activation still has to be assessed.

A screen for inhibitors of DNA recombination: identification of two new spirostanol glycosides from Chamaedorea linearis.

Two new glycosides have been isolated from the MeOH extract of the stem wood and stem bark of an Ecuadorian plant Chamaedorea linearis, and their structures have been determined by spectroscopic means and X-ray analysis of the aglycone to be 1-O-[beta-L-fucopyranosyl-(4'-sulfate)]-25R,5 alpha-spirostane-1 beta, 3 beta-diol [1]) and 1-O-[beta-L-fucopyranosyl-(4'-sulfate)]-25R,5 alpha-spirostane-1 alpha, 3 beta-diol [2]. These compounds were identified in a screen for inhibitors of recombinational DNA repair. Cytotoxic activity was also demonstrated.

Some new aryl-sydnones: effects on murine tumours.

The effects of new aryl-sydnones: 3-[4-X-3-nitrophenyl]-1,2,3-oxadiazolium-5-olates, where X = Cl (SYD-1); pyrrolidino (SYD-2); piperidino (SYD-3) and morpholino (SYD-4) on the survival of mice bearing Sarcoma 180, Ehrlich carcinoma, B10MCII (Fibrous histiocytoma) and L1210 leukemia ascitic tumours, on the proliferation of cultured tumour cells and on the synthesis of DNA in L1210 leukemia were determined. SYD-1 and SYD-2 in vivo significantly enhanced the survival of S180, Ehrilich and B10MCII tumour-bearing mice. Furthermore, SYD-2 showed significant activity against L1210. SYD-3 and SYD-4 did not show antitumour activity. SYD-1, in vitro was the most cytotoxic against all the above tumour cells. All of the drugs tested inhibited thymidine uptake by L1210 cells, SYD-4 being the least active.

Actividad antitumoral del CCNU obtenido en Cuba / Antineoplasic activity of CCNU obtained in Cuba

El (1-[2-cloroetil] 1-nitroso, 3 ciclohexil urea) (CCNU) es una droga antitumoral que forma parte actualmente de múltiples esquemas de poliquimioterapia en el tratamienmto de diferentes localizaciones y su obtención en el país aumentará la disponibilidad de este producto. El presente trabajo evalúa la actividad, en comparación con el producto comercial usado actualmente en la clínica oncológica y por los resultados obtenidos en los tumores experimentales utilizados, ambos productos manifiestan semejante actividad antitumoral

Actividad antitumoral del CCNU obtenido en Cuba / Antineoplasic activity of CCNU obtained in Cuba

El (1-[2-cloroetil] 1-nitroso, 3 ciclohexil urea) (CCNU) es una droga antitumoral que forma parte actualmente de múltiples esquemas de poliquimioterapia en el tratamienmto de diferentes localizaciones y su obtención en el país aumentará la disponibilidad de este producto. El presente trabajo evalúa la actividad, en comparación con el producto comercial usado actualmente en la clínica oncológica y por los resultados obtenidos en los tumores experimentales utilizados, ambos productos manifiestan semejante actividad antitumoral

Sinergismo del Cis-Diaminodicloro Platino (II) (CIS-DDP) y el M-Tiocarbamal en el tratamiento de la leucemia L-1210 / Synergism of Cis-Platinum Diamminodichloride (II) (CIS-DDP) and M-Thiocarbamol in the treatment of leukemia L-1210

El M-tiocarbamal (morfolinditiocarbamato de sodio) es un producto sintético con el cual en estos momentos se lleva a cabo el ensayo clínico fase I. Experimentalmente se combinó con el Cis-DDP en el tratamiento de la leucemia L-1210. Los resultados obtenidos evidencian la potenciación de la acción antitumoral del Cis-DDP cuando el M-tiocarbamal se administra simultáneo o después de la administración del citostático

Sinergismo del Cis-Diaminodicloro Platino (II) (CIS-DDP) y el M-Tiocarbamal en el tratamiento de la leucemia L-1210 / Synergism of Cis-Platinum Diamminodichloride (II) (CIS-DDP) and M-Thiocarbamol in the treatment of leukemia L-1210

El M-tiocarbamal (morfolinditiocarbamato de sodio) es un producto sintético con el cual en estos momentos se lleva a cabo el ensayo clínico fase I. Experimentalmente se combinó con el Cis-DDP en el tratamiento de la leucemia L-1210. Los resultados obtenidos evidencian la potenciación de la acción antitumoral del Cis-DDP cuando el M-tiocarbamal se administra simultáneo o después de la administración del citostático