Effect of nanoparticle size on their distribution and retention in chronic inflammation sites.

Nanomedicines are increasingly researched and used for the treatment of chronic inflammatory diseases. Herein, the effect of the size of nanoparticles on their distribution and retention in chronic inflammatory sites, as compared to healthy tissues, was studied in a mouse model with chronic inflammation in one of the hind footpads. Using PEGylated gold nanoparticles of 2, 10, 100, and 200 nm, we found that although the smaller nanoparticles of 2 and 10 nm showed greater distribution and slower clearance in the inflamed footpad than the relatively larger nanoparticles of 100 and 200 nm, the larger nanoparticles of 100 and 200 nm were more selectively distributed in the inflamed hind footpad than in the healthy hind footpad in the same mouse. Based on these findings, we prepared protein nanoparticles of 100-200 nm with albumin, IgG antibody, or anti-TNF-α monoclonal antibody (mAb). The nanoparticles can release proteins in response to high redox activity and/or low pH, conditions seen in chronic inflammation sites. We then showed that upon intravenous injection, those stimuli-responsive protein nanoparticles distributed more selectively in the inflamed footpad than free proteins and remained longer in the inflamed footpad than similar protein nanoparticles that are not sensitive to high redox activity or low pH. These findings support the feasibility of increasing the selectivity of nanomedicines and protein therapeutics to chronic inflammation sites and prolonging their retention at the sites by innovative nanoparticle engineering.

4-(N)-Docosahexaenoyl 2', 2'-difluorodeoxycytidine induces immunogenic cell death in colon and pancreatic carcinoma models as a single agent.

PURPOSE: Docosahexaenoyl difluorodeoxycytidine (DHA-dFdC) is an amide with potent, broad-spectrum antitumor activity. In the present study, DHA-dFdC's ability to induce immunogenic cell death (ICD) was tested using CT26 mouse colorectal cancer cells, an established cell line commonly used for identifying ICD inducers, as well as Panc-02 mouse pancreatic cancer cells. METHODS: The three primary surrogate markers of ICD (i.e., calreticulin (CRT) surface translocation, ATP release, and high mobility group box 1 protein (HMGB1) release) were measured in vitro. To confirm DHA-dFdC's ability to induce ICD in vivo, the gold standard mouse vaccination studies were conducted using both CT26 and Panc-02 models. Additionally, the effect of DHA-dFdC on tumor response to anti-programmed cell death protein 1 monoclonal antibody (anti-PD-1 mAb) were tested in mice with pre-established Panc-02 tumors. RNA sequencing experiments were conducted on PANC-1 human pancreatic cancer cells treated with DHA-dFdC, dFdC, or vehicle control in vitro. RESULTS: DHA-dFdC elicited CRT surface translocation and ATP and HMGB1 release in both cell lines. Immunization of mice with CT26 or Panc-02 cells pretreated with DHA-dFdC prevented or delayed the development of corresponding secondary live challenge tumor. DHA-dFdC enabled Panc-02 tumors to respond to anti-PD-1 mAb. RNA sequencing experiments revealed that DHA-dFdC and dFdC differentially impacted genes related to the KRAS, TP53, and inflammatory pathways, and DHA-dFdC enriched for the unfolded protein response (UPR) compared to control, providing insight into DHA-dFdC's potential mechanism of inducing ICD. CONCLUSION: DHA-dFdC is a bona fide ICD inducer and can render pancreatic tumors responsive to anti-PD-1 mAb therapy.

Effect of surface mannosylation on the cytotoxicity and cellular uptake of stearoyl gemcitabine-incorporated, acid-sensitive micelles.

Elevated expression of C-type like receptors (CLRs) by tumor cells and tumor-associated macrophages (TAMs) present a unique target for the delivery of anticancer agents. Stearoyl gemcitabine (GemC18)-incorporated, acid-sensitive micelles (G-AS-M) prepared with a stearoyl polyethylene glycol (PEG2000) hydrazone were surface-mannosylated in this study for potential targeted killing of tumor cells and TAMs. The surface mannosylated micelles (i.e. G-MAS-M) were significantly more cytotoxic than the G-AS-M micelles to macrophages and tumor cells that express CLRs. Surprisingly, the uptake of GemC18 in the mannosylated G-MAS-M micelles by the macrophages and tumor cells was lower than that of GemC18 in the G-AS-M micelles. The lack of correlation between the cytoxicity and cellular uptake of GemC18 in the micelles was likely caused by a reduction in the sensitivity of the hydrazone bond linking the PEG2000 to the mannosylated G-MAS-M micelles to hydrolysis, resulting in more stable micelles.

Intranasal delivery of a nicotine vaccine candidate induces antibodies in mouse blood and lung mucosal secretions that specifically neutralize nicotine.

OBJECTIVE: Cigarette smoking is one of the leading causes of death in the world. The majority of the smokers have tried to quit, but only a few of them were able to achieve long-term abstinence, due to the high addictiveness of nicotine. Nicotine-specific antibodies have the potential to block the euphoric effect of nicotine by forming antibody-antigen complexes in the blood circulation. Since nicotine is taken largely by inhalation, inducing anti-nicotine antibodies in lung and nasal mucosal secretions, in addition to blood circulation, is expected to be beneficial. SIGNIFICANCE: The importance of this study is to establish the feasibility of inducing nicotine-neutralizing antibodies not only in the blood, but also in the lung and nasal mucosal secretions, by intranasal administration of a nicotine vaccine candidate. METHODS: Nicotine-keyhole limpet hemocyanin conjugate (Nic-KLH) was prepared and mixed with monophosphoryl lipid A (MPL) as an adjuvant. Nic-KLH/MPL was given intranasally or subcutaneously to mice, and the titers, affinity, and specificity of the nicotine-specific antibodies in nasal and lung mucosal secretions and blood samples were determined using (competitive) ELISA. RESULTS: Nasal Nic-KLH/MPL immunization elicited robust nicotine-specific neutralizing IgA in mouse nasal and lung secretions, in additional to anti-nicotine IgG in blood circulation. The nicotine-specific IgG level in mice nasally immunized with Nic-KLH/MPL was lower than in mice subcutaneously immunized with the same Nic-KLH/MPL, but a heterologous prime-boost immunization strategy helped to increase it. CONCLUSION: Intranasal immunization with a nicotine vaccine candidate can induce systemic and mucosal antibodies that specifically neutralize nicotine.

Effect of a Solid Lipid Nanoparticle Formulation on the Bioavailability of 4-(N)-Docosahexaenoyl 2', 2'-Difluorodeoxycytidine After Oral Administration.

Previously, we developed a solid lipid nanoparticle (SLN) formulation of 4-(N)-docosahexaenoyl 2', 2'-difluorodeoxycytidine (DHA-dFdC), a compound with promising antitumor activity. Herein, we studied the feasibility of administering the DHA-dFdC by the oral route using the solid lipid nanoparticles (i.e., DHA-dFdC-SLNs). In simulated gastrointestinal fluids, the DHA-dFdC-SLNs did not aggregate. The release of the DHA-dFdC from the solid lipid nanoparticles in simulated gastrointestinal fluid was slow, but was slightly faster in simulated intestinal fluid than in simulated gastric fluid. In mice orally administered with DHA-dFdC-SLNs, plasma DHA-dFdC concentration vs. time curve has a Tmax of ~ 1.7 h and a Cmax of 17.01 µg/mL. The absolute oral bioavailability of DHA-dFdC when given as DHA-dFdC-SLNs was ~ 68% (based on AUC0-24 h values), while the relative oral bioavailability DHA-dFdC (compared with DHA-dFdC in a Tween 80/ethanol-in-water solution) was 126%. Finally, in mice with pre-establish B16-F10 murine melanoma, oral DHA-dFdC-SLNs increased their survival significantly, as compared with oral administration of the DHA-dFdC solution. It is concluded that the solid lipid nanoparticle formulation increased the bioavailability of the DHA-dFdC upon oral administration, as compared with the DHA-dFdC solution.

Effect of the Ratio of Betamethasone to TNF-α siRNA Coencapsulated in Solid Lipid Nanoparticles on the Acute Proinflammatory Activity of the Nanoparticles.

There is evidence that encapsulating glucocorticoids into nucleic acid-containing nanoparticles reduces the inflammatory toxicities of the nanoparticles. Herein, using betamethasone acetate (BA), a glucocorticoid, and a solid lipid nanoparticle formulation of siRNA, we confirmed that coencapsulating BA into the siRNA solid lipid nanoparticles significantly reduced the proinflammatory activity of the siRNA nanoparticles in a mouse model. Using TNF-α siRNA, we then showed that the BA and TNF-α siRNA coencapsulated into the solid lipid nanoparticles acted as a dual anti-inflammatory and synergistically reduced TNF-α release by mouse macrophages in culture following stimulation with lipopolysaccharide, as compared to solid lipid nanoparticles encapsulated with TNF-α siRNA or BA alone. Importantly, upon studying the effect of the ratio of BA and TNF-α siRNA on the proinflammatory activity of the resultant nanoparticles, we identified that BA and TNF-α siRNA coencapsulated solid lipid nanoparticles prepared with a BA to TNF-α siRNA weight ratio of 2:1 induced the lowest proinflammatory cytokine production by macrophages in culture. This result was in comparison to nanoparticles prepared with BA to TNF-α siRNA ratios both higher and lower than 2:1 (i.e., 4:1, 1:1, and 0.5:1) and is likely due to differences in molecular interactions among the various components in the BA and TNF-α-siRNA coencapsulated solid lipid nanoparticles at these ratios. Encapsulating glucocorticoids into siRNA-nanoparticles represents a viable strategy to reduce the proinflammatory activity of the nanoparticles; however, the ratio of the glucocorticoid to siRNA in the nanoparticles requires optimization.

A solid lipid nanoparticle formulation of 4-(N)-docosahexaenoyl 2', 2'-difluorodeoxycytidine with increased solubility, stability, and antitumor activity.

Previously, we synthesized 4-(N)-docosahexaenoyl 2', 2'-difluorodeoxycytidine (DHA-dFdC), a novel lipophilic compound with a potent, broad-spectrum antitumor activity. Herein, we report a solid lipid nanoparticle (SLN) formulation of DHA-dFdC with improved apparent aqueous solubility, chemical stability, as well as efficacy in a mouse model. The SLNs were prepared from lecithin/glycerol monostearate-in-water emulsions emulsified with D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) and Tween 20. The resultant DHA-dFdC-SLNs were 102.2 ±â€¯7.3 nm in diameter and increased the apparent solubility of DHA-dFdC in water to at least 5.2 mg/mL, more than 200-fold higher than its intrinsic water solubility. DHA-dFdC in a lyophilized powder of DHA-dFdC-SLNs was significantly more stable than the waxy solid of pure DHA-dFdC. DHA-dFdC-SLNs also showed an increased cytotoxicity against certain tumor cells than DHA-dFdC. The plasma concentration of DHA-dFdC in mice intravenously injected with DHA-dFdC-SLNs in dispersion followed a bi-exponential model, with a half-life of ~44 h. In mice bearing B16-F10 murine melanoma, DHA-dFdC-SLNs were significantly more effective than DHA-dFdC in controlling the tumor growth. In addition, histology evaluation revealed a high level of apoptosis and tumor encapsulation in tumors in mice treated with DHA-dFdC-SLNs. DHA-dFdC-SLNs represents a new DHA-dFdC formulation with improved antitumor activity.

Zoledronic Acid-containing Nanoparticles With Minimum Premature Release Show Enhanced Activity Against Extraskeletal Tumor.

Bisphosphonates are generally used to treat bone diseases, such as bone metastasis from cancer. There is evidence that, through the modification of the pharmacokinetics and biodistribution of bisphosphonates by formulating them into nanoparticles, they may be able to treat extraskeletal tumors. However, many previously reported bisphosphonate nanoparticle formulations show extensive premature release of bisphosphonates. Herein, using zoledronate (Zol), a third-generation bisphosphonate, we developed a new Zol nanoparticle formulation (denoted as Zol-NPs) by encapsulating anionic lipid-coated Zol-calcium nanocomplexes into poly(lactic- co-glycolic) acid nanoparticles emulsified with octadecanoic acid-hydrazone-polyethylene glycol (2000), an acid-sensitive cleavable emulsifying agent. The resultant Zol-NPs, about 180 nm in hydrodynamic diameter, show very limited premature release of Zol (i.e., <5% in 48 h in a simulated physiological condition) and enhanced cytotoxicity to both murine cancer cells and macrophages. In a mouse model with orthotopically transplanted mammary tumors, Zol-NPs significantly reduced the distribution of Zol in bones, but increased its distribution in tumors. Importantly, Zol-NPs also significantly inhibited tumor growth, whereas the equivalent dose of free Zol did not. This platform technology may be exploited to treat extraskeletal tumors with bisphosphonates.

Intranasal immunization with aluminum salt-adjuvanted dry powder vaccine.

Intranasal vaccination using dry powder vaccine formulation represents an attractive, non-invasive vaccination modality with better storage stability and added protection at the mucosal surfaces. Herein we report that it is feasible to induce specific mucosal and systemic antibody responses by intranasal immunization with a dry powder vaccine adjuvanted with an insoluble aluminum salt. The dry powder vaccine was prepared by thin-film freeze-drying of a model antigen, ovalbumin, adsorbed on aluminum (oxy)hydroxide as an adjuvant. Special emphasis was placed on the characterization of the dry powder vaccine formulation that can be realistically used in humans by a nasal dry powder delivery device. The vaccine powder was found to have "passable" to "good" flow properties, and the vaccine was uniformly distributed in the dry powder. An in vitro nasal deposition study using nasal casts of adult humans showed that around 90% of the powder was deposited in the nasal cavity. Intranasal immunization of rats with the dry powder vaccine elicited a specific serum antibody response as well as specific IgA responses in the nose and lung secretions of the rats. This study demonstrates the generation of systemic and mucosal immune responses by intranasal immunization using a dry powder vaccine adjuvanted with an aluminum salt.

Lipid nanoparticles with minimum burst release of TNF-α siRNA show strong activity against rheumatoid arthritis unresponsive to methotrexate.

TNF-α siRNA has shown promising therapeutic benefits in animal models of rheumatoid arthritis. However, there continues to be a need for siRNA delivery systems that have high siRNA encapsulation efficiency and minimum burst release of TNF-α siRNA, and can target inflamed tissues after intravenous administration. Herein we report a novel acid-sensitive sheddable PEGylated solid-lipid nanoparticle formulation of TNF-α-siRNA, AS-TNF-α-siRNA-SLNs, prepared by incorporating lipophilized TNF-α-siRNA into solid-lipid nanoparticles composed of biocompatible lipids such as lecithin and cholesterol. The nanoparticles are approximately 120 nm in diameter, have a high siRNA encapsulation efficiency (>90%) and a minimum burst release of siRNA (<5%), and increase the deilvery of the siRNA in chronic inflammation sites in mouse models, including in a mouse model with collagen-induced arthritis. Importantly, in a mouse model of collagen antibody-induced arthritis that does not respond to methotrexate therapy, intravenous injection of the AS-TNF-α-siRNA-SLNs significantly reduced paw thickness, bone loss, and histopathological scores. These findings highlight the potential of using this novel siRNA nanoparticle formulation to effectively treat arthritis, potentially in patients who do not respond adequately to methotrexate.

Oral 4-(N)-stearoyl gemcitabine nanoparticles inhibit tumor growth in mouse models.

In spite of recent advances in targeted tumor therapy, systemic chemotherapy with cytotoxic agents remains a vital cancer treatment modality. Gemcitabine is a nucleoside analog commonly used in the treatment of various solid tumors, but an oral gemcitabine dosage form remain unavailable. Previously, we developed the 4-(N)-stearoyl gemcitabine solid lipid nanoparticles (GemC18-SLNs) by incorporating 4-(N)-stearoyl gemcitabine (GemC18), an amide prodrug of gemcitabine, into solid lipid nanoparticles. GemC18-SLNs, when administered intravenously, showed strong antitumor activity against various human and mouse tumors in mouse models. In the present study, we defined the plasma pharmacokinetics of gemcitabine when GemC18-SLNs were given orally to healthy mice and evaluated the antitumor activity of GemC18-SLNs when given orally in mouse models of lung cancer. In mice orally gavaged with GemC18-SLNs, plasma gemcitabine concentration followed an absorption phase and then clearance phase, with a Tmax of ~2 h. The absolute oral bioavailability of gemcitabine in the GemC18-SLNs was ~70% (based on AUC0-24 h values). In mice with pre-established tumors (i.e. mouse TC-1 or LLC lung cancer cells), oral GemC18-SLNs significantly inhibited the tumor growth and increased mouse survival time, as compared to the molar equivalent dose of gemcitabine hydrochloride or GemC18 in vegetable oil or in Tween 20. Immunohistostaining revealed that oral GemC18-SLNs also have significant antiproliferative, antiangiogenic, and proapoptotic activity in LLC tumors. Formulating a lipophilic amide prodrug of gemcitabine into solid lipid nanoparticles may represent a viable approach toward developing a safe and efficacious gemcitabine oral dosage form.

Aluminum (Oxy)Hydroxide Nanosticks Synthesized in Bicontinuous Reverse Microemulsion Have Potent Vaccine Adjuvant Activity.

Insoluble aluminum salts such as aluminum (oxy)hydroxide are commonly used as vaccine adjuvants. Recently, there is evidence suggesting that the adjuvant activity of aluminum salt-based materials is tightly related to their physicochemical properties, including nanometer-scale size, shape with long aspect ratio, and low degree of crystallinity. Herein, for the first time, the bicontinuous reverse microemulsion (RM) technique was utilized to synthesize stick-like monodisperse aluminum (oxy)hydroxide nanoparticles with a long aspect ratio of ∼10, length of ∼80 nm, and low degree of crystallinity (denoted as Al-nanosticks). Moreover, the relationship between the physicochemical properties of Al-nanosticks and the bicontinuous RM was discussed. Compared to the commercial Alhydrogel, which contains micrometer-scale aluminum oxyhydroxide particular aggregates with moderate degree of crystallinity, the Al-nanosticks are more effective in adsorbing and delivering antigens (e.g., ovalbumin, OVA) into antigen-presenting cells, activating inflammasomes, and potentiating OVA-specific antibody responses in a mouse model. It is concluded that the aluminum (oxy)hydroxide nanosticks synthesized in the bicontinuous RM are promising new aluminum salt-based vaccine adjuvants.

Acid-Sensitive Sheddable PEGylated, Mannose-Modified Nanoparticles Increase the Delivery of Betamethasone to Chronic Inflammation Sites in a Mouse Model.

Inflammation is implicated in a host of chronic illnesses. Within these inflamed tissues, the pH of the microenvironment is decreased and immune cells, particularly macrophages, infiltrate the area. Additionally, the vascular integrity of these sites is altered with increased fenestrations between endothelial cells. These distinctive properties may be exploited to enhance targeted delivery of anti-inflammatory therapies. Using a mouse model of chronic inflammation, we previously showed that acid-sensitive sheddable PEGylation increases the distribution and retention of nanoparticles in chronic inflammation sites. Here we demonstrated that surface modification of the acid-sensitive sheddable PEGylated nanoparticles with mannose, a ligand to mannose receptors present in chronic inflammation sites, significantly increases the targeted delivery of the nanoparticles to these areas. Furthermore, we showed that the acid-sensitive sheddable PEGylated, mannose-modified nanoparticles are able to significantly increase the delivery of betamethasone-21-acetate (BA), a model anti-inflammatory compound, to chronic inflammation sites as compared to free BA. These results highlight the ability to engineer formulations to target chronic inflammation sites by exploiting the microenvironment of these regions.

Reverse Microemulsion-Based Synthesis of (Bis)phosphonate-Metal Materials with Controllable Physical Properties: An Example Using Zoledronic Acid-Calcium Complexes.

The development of phosphonate-metal materials is tightly related to the advancement in their synthesis methods. Herein, using zoledronic acid (Zol), a bisphosphonate (bioacitve phosphonate with a "P-C-P" structure), and calcium as model molecules, we applied the reverse microemulsion (RM) method to synthesize a series of Zol-Ca complexes. We comprehensively (i) studied the relationship between RM conditions, including the component ratio of RM, cosurfactants, reaction time, reactant concentration, reaction temperature, and the presence of a phospholipid, 1, 2-dioleoyl-sn-glycero-3-phosphate acid (DOPA), and the physical properties of the complexes synthesized (i.e., shape, size, uniformity, monodispersity, and hydrophilicity/hydrophobicity) and (ii) explored the underlying mechanisms. To evaluate the biomedical application potential of the Zol-Ca complexes synthesized, one type of hydrophobic, DOPA-coated spherical Zol-Ca complexes (denoted as Zol-Ca@DOPA) was formulated into a PEGylated lipid-based nanoparticle formulation (i.e., Zol-Ca@bilipid NPs, ∼24 nm in diameter). In a mouse model with orthotopic mammary tumors, the Zol-Ca@bilipid NPs significantly enhanced the distribution of Zol in tumors, as compared to free Zol. It is expected that the RM-based synthesis of (bis)phosphonate-metal materials with controllable physical properties will help expand their applications.

Preclinical Evaluation of the Short-Term Toxicity of 4-(N)-Docosahexaenoyl 2´, 2´- Difluorodeoxycytidine (DHA-dFdC).

PURPOSE: This study was designed to test the short-term toxicity of DHA-dFdC in a mouse model and its efficacy in a mouse model of leukemia at or below its repeat-dose maximum tolerated dose (RD-MTD). METHOD: A repeat-dose dose-ranging toxicity study was designed to determine the tolerability of DHA-dFdC when administered to DBA/2 mice by intravenous (i.v.) injection on a repeat-dose schedule (i.e. injections on days 0, 3, 7, 10, and 13). In order to determine the effect of a lethal dose of DHA-dFdC, mice were injected i.v. with three doses of DHA-dFdC at 100 mg/kg on days 0, 3, and 5 (i.e. a lethal-RD). The body weight of mice was recorded two or three times a week. At the end of the study, major organs (i.e. heart, liver, spleen, kidneys, lung, and pancreas) of mice that received the lethal-RD or RD-MTD were weighed, and blood samples were collected for analyses. Finally, DHA-dFdC was i.v. injected into DBA/2 mice with syngeneic L1210 mouse leukemia cells to evaluate its efficacy at or below RD-MTD. RESULTS: The RD-MTD of DHA-dFdC is 50 mg/kg. At 100 mg/kg, a lethal-RD, DHA-dFdC decreases the weights of mouse spleen and liver and significantly affected certain blood parameters (i.e. white blood cells, lymphocytes, eosinophils, and neutrophil segmented). At or below its RD-MTD, DHA-dFdC significantly prolonged the survival of L1210 leukemia-bearing mice. CONCLUSION: DHA-dFdC has dose-dependent toxicity, affecting mainly spleen at a lethal-RD. At or below its RD-MTD, DHA-dFdC is effective against leukemia in a mouse model.

Tumor-Associated Macrophage-Mediated Targeted Therapy of Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most aggressive form of breast cancer. TNBC is often infiltrated with a large number of macrophages, which in turn promote tumor growth and metastasis. In this study, tumor-associated macrophages (TAMs) were exploited as a target to deliver doxorubicin (DOX), a chemotherapeutic agent, to TNBC using nanoparticles surface-functionalized by (i) acid-sensitive sheddable PEGylation and (ii) modifying with mannose (i.e., DOX-AS-M-PLGA-NPs). In mice with orthotopic M-Wnt triple-negative mammary tumors, a single intravenous injection of DOX-AS-M-PLGA-NPs significantly reduced macrophage population in tumors within 2 days, and the density of the macrophages recovered slowly. Repeated injections of DOX-AS-M-PLGA-NPs can help maintain the population of the macrophages at a lower level. In M-Wnt tumor-bearing mice that were pretreated with zoledronic acid to nonselectively deplete macrophages, the TAM-targeting DOX-AS-M-PLGA-NPs were not more effective than the DOX-AS-PLGA-NPs that were not surface-modified with mannose and thus do not target TAMs in controlling tumor growth. However, in M-Wnt tumor-bearing mice that were not pretreated with zoledronic acid, the TAM-targeting DOX-AS-M-PLGA-NPs were significantly more effective than the nontargeting DOX-AS-PLGA-NPs in controlling the tumor growth. The AS-M-PLGA-NPs or other nanoparticles surface-functionalized similarly, when loaded with a chemotherapeutic agent commonly used in adjuvant therapy of TNBC, may be developed into targeted therapy for TNBC.

Synthesis, Characterization, and In Vitro and In Vivo Evaluations of 4-(N)-Docosahexaenoyl 2', 2'-Difluorodeoxycytidine with Potent and Broad-Spectrum Antitumor Activity.

In this study, a new compound, 4-(N)-docosahexaenoyl 2', 2'-difluorodeoxycytidine (DHA-dFdC), was synthesized and characterized. Its antitumor activity was evaluated in cell culture and in mouse models of pancreatic cancer. DHA-dFdC is a poorly soluble, pale yellow waxy solid, with a molecular mass of 573.3Da and a melting point of about 96°C. The activation energy for the degradation of DHA-dFdC in an aqueous Tween 80-based solution is 12.86kcal/mol, whereas its stability is significantly higher in the presence of vitamin E. NCI-60 DTP Human Tumor Cell Line Screening revealed that DHA-dFdC has potent and broad-spectrum antitumor activity, especially in leukemia, renal, and central nervous system cancer cell lines. In human and murine pancreatic cancer cell lines, the IC50 value of DHA-dFdC was up to 10(5)-fold lower than that of dFdC. The elimination of DHA-dFdC in mouse plasma appeared to follow a biexponential model, with a terminal phase t1/2 of about 58minutes. DHA-dFdC significantly extended the survival of genetically engineered mice that spontaneously develop pancreatic ductal adenocarcinoma. In nude mice with subcutaneously implanted human Panc-1 pancreatic tumors, the antitumor activity of DHA-dFdC was significantly stronger than the molar equivalent of dFdC alone, DHA alone, or the physical mixture of them (1:1, molar ratio). DHA-dFdC also significantly inhibited the growth of Panc-1 tumors orthotopically implanted in the pancreas of nude mice, whereas the molar equivalent dose of dFdC alone did not show any significant activity. DHA-dFdC is a promising compound for the potential treatment of cancers in organs such as the pancreas.

Spironolactone decreases DOCA-salt-induced organ damage by blocking the activation of T helper 17 and the downregulation of regulatory T lymphocytes.

Adaptive immune response has been implicated in inflammation and fibrosis as a result of exposure to mineralocorticoids and a high-salt diet. We hypothesized that in mineralocorticoid-salt-induced hypertension, activation of the mineralocorticoid receptor alters the T-helper 17 lymphocyte (Th17)/regulatory T-lymphocyte/interleukin-17 (IL-17) pathway, contributing to cardiac and renal damage. We studied the inflammatory response and tissue damage in rats treated with deoxycorticosterone acetate and high-salt diet (DOCA-salt), with or without mineralocorticoid receptor inhibition by spironolactone. To determine whether Th17 differentiation in DOCA-salt rats is caused by hypertension per se, DOCA-salt rats received antihypertensive therapy. In addition, to evaluate the pathogenic role of IL-17 in hypertension and tissue damage, we studied the effect of IL-17 blockade with a specific antibody (anti-IL-17). We found activation of Th17 cells and downregulation of forkhead box P3 mRNA in peripheral tissues, heart, and kidneys of DOCA-salt-treated rats. Spironolactone treatment prevented Th17 cell activation and increased numbers of forkhead box P3-positive cells relative to DOCA-salt rats. Antihypertensive therapy did not ameliorate Th17 activation in rats. Treatment of DOCA-salt rats with anti-IL-17 significantly reduced arterial hypertension as well as expression of profibrotic and proinflammatory mediators and collagen deposits in the heart and kidney. We conclude that mineralocorticoid receptor activation alters the Th17/regulatory T-lymphocyte/IL-17 pathway in mineralocorticoid-dependent hypertension as part of an inflammatory mechanism contributing to fibrosis.

Thyroid hormone administration induces rat liver Nrf2 activation: suppression by N-acetylcysteine pretreatment.

BACKGROUND: Oxidative stress associated with 3,3',5-triiodo-l-thyronine (T(3))-induced calorigenesis upregulates the hepatic expression of mediators of cytoprotective mechanisms. The aim of this study was to evaluate the hypothesis that in vivo T(3) administration triggers a redox-mediated translocation of the cytoprotective nuclear transcription factor erythroid 2-related factor 2 (Nrf2) from the cytosol to the nucleus in rat liver. Such translocation of transcription factors is considered to be an activating step. MATERIALS AND METHODS: The effect of T(3) administration in the presence and absence of N-acetylcysteine (NAC) on cytosol-to-nuclear translocation of Nrf2 was evaluated, with inhibition of this process by NAC taken as evidence that the process was redox mediated. Male Sprague-Dawley rats weighing 180-200 g were given a single intraperitoneal dose of 0.1 mg T(3)/kg. Another group of rats were given the same dose of T(3) and were also pretreated with NAC (0.5 g/kg) at 0.5 hour before T(3) administration. Two other groups of rats received vehicle treatment and NAC, respectively. Following these treatments, rectal temperature of the animals, liver O(2) consumption, serum and hepatic levels of 8-isoprostanes, and liver protein levels of Nrf2, Akt, p38, and thioredoxin (Western blot) were determined at different times up to 48 hours. RESULTS: T(3) administration induced a significant increase in the hepatic nuclear levels of Nrf2 at 1 and 2 hours after treatment and a concomitant decrease in cytosolic Nrf2. It also increased hepatic thioredoxin, a protein whose gene transcription is induced by nuclear Nrf2. Levels of nuclear Nrf2 were at a plateau from 4 to 6 hours after T(3). Rectal temperature of the animals rose from 36.6°C to 37.5°C as did liver O(2) consumption. Serum and liver 8-isoprostanes levels increased (p < 0.05) from 38.4 ± 4.0 pg/mL (n = 4) to 69.2 ± 2.0 pg/mL (n = 3) and from 0.75 ± 0.09 ng/g liver (n = 3) to 1.53 ± 0.10 ng/g liver (n = 5), respectively. In the group of rats pretreated with NAC, the increase in cytosol-to-nuclear translocation of Nrf2 was only 28% that induced by T(3). In addition, T(3) induced liver Akt and p38 activation during the period of 1-4 hours after T(3) administration. p38 activation at 2 hours after T(3) administration was abolished in NAC-pretreated animals. CONCLUSIONS: In vivo T(3) administration leads to a rapid and transient cytosol-to-nuclear translocation of liver Nrf2. This appears to be promoted by a redox-dependent mechanism as it is blocked by NAC. It may also be contributed by concomitant p38 activation, which in turn promoted Nrf2 phosphorylation. Nrf2 cytosol-to-nuclear translocation may represent a novel cytoprotective mechanism of T(3) to limit free radical or electrophile toxicity, as this would likely entail promoting thioredoxin production.