Highly Soluble Dacarbazine Multicomponent Crystals Less Prone to Photodegradation.

Dacarbazine (DTIC) is a widely prescribed oncolytic agent to treat advanced malignant melanomas. Nevertheless, the drug is known for exhibiting low and pH-dependent solubility, in addition to being photosensitive. These features imply the formation of the inactive photodegradation product 2-azahypoxanthine (2-AZA) during pharmaceutical manufacturing and even drug administration. We have focused on developing novel DTIC salt/cocrystal forms with enhanced solubility and dissolution behaviors to overcome or minimize this undesirable biopharmaceutical profile. By cocrystallization techniques, two salts, two cocrystals, and one salt-cocrystal have been successfully prepared through reactions with aliphatic carboxylic acids. A detailed structural study of these new multicomponent crystals was conducted using X-ray diffraction (SCXRD, PXRD), spectroscopic (FT-IR and 1H NMR), and thermal (TG and DSC) analyses. Most DTIC crystal forms reported display substantial enhancements in solubility (up to 19-fold), with faster intrinsic dissolution rates (from 1.3 to 22-fold), contributing positively to reducing the photodegradation of DTIC in solution. These findings reinforce the potential of these new solid forms to enhance the limited DTIC biopharmaceutical profile.

Desensitization of metastatic melanoma cells to therapeutic treatment through repeated exposure to dacarbazine.

Aberrant anti-cancer drug efflux mediated by membrane protein ABC transporters (ABCB5 and ABCG2) is thought to characterize melanoma heterogeneous chemoresistant populations, presumed to have unlimited proliferative and self-renewal abilities. Therefore, this study primarily aimed to investigate whether continuous exposure of melanoma cells to dacarbazine (DTIC) chemotherapeutic drug enriches cultures with therapy resistant cells. Thereafter, we sought to determine whether combining the genotoxic activity of DTIC with the oxidative insults of hypericin activated photodynamic therapy (HYP-PDT) could synergized to kill heterogenous chemoresistant melanoma populations. This study revealed that DTIC resistant (UCT Mel-1DTICR2) melanoma cells were less sensitive to all therapies than parental melanoma cells (UCT Mel-1), yet combination therapy was the most efficient. At the exception of DTIC treatment, both HYP-PDT and the combination therapy were effective in significantly reducing the Hoechst non-effluxing dye melanoma main populations (MP) compared to their side population (SP) counterparts. Likewise, HYP-PDT and combination therapy significantly reduced self-renewal capacity, increased expression of ABCB5 and ABCG2 transporters and differentially induced cell cycle arrest and cell death (apoptosis or necrosis) depending on the melanoma MP cell type. Collectively, combination therapy could synergistically reduce melanoma proliferative and clonogenic potential. However, further research is needed to decipher the cellular mechanisms underlying this resistance which would enable combination therapy to reach therapeutic fruition.

Molecular Docking Studies and Inhibition Properties of Some Antineoplastic Agents against Paraoxonase-I.

BACKGROUND: Currently, most of the drugs used in clinical applications show their pharmacological influences by inhibiting or activating enzymes. Therefore, enzyme inhibitors have an essential place in the drug design for many diseases. OBJECTIVE: The current study aimed to contribute to this growing drug design field (i.e., medicine discovery and development) by analyzing enzyme-drug interactions. METHODS: For this reason, Paraoxonase-I (PON1) enzyme was purified from fresh human serum by using rapid chromatographic techniques. Additionally, the inhibition effects of some antineoplastic agents were researched on the PON1. RESULTS: The enzyme was obtained with a specific activity of 2603.57 EU/mg protein. IC50 values for pemetrexed disodium, irinotecan hydrochloride, dacarbazine, and azacitidine were determined to be 9.63µM, 30.13µM, 53.31µM, and 21.00mM, respectively. These agents found to strongly inhibit PON1, with Ki constants ranging from 8.29±1.47µM to 23.34±2.71mM. Dacarbazine and azacitidine showed non-competitive inhibition, while other drugs showed competitive inhibition. Furthermore, molecular docking was performed using maestro for these agents. Among these, irinotecan hydrochloride and pemetrexed disodium possess the binding energy of -5.46 and -8.43 kcal/mol, respectively. CONCLUSION: The interaction studies indicated that these agents with the PON1 possess binding affinity.

Electrospun PVA-Dacarbazine nanofibers as a novel nano brain-implant for treatment of glioblastoma: in silico and in vitro characterization.

Malignant glioblastoma (GB) treatment consists of resection surgery followed by radiotherapy and chemotherapy (CT). Despite several implications, such as systemic toxicity and low efficacy, CT continues to be used for GB therapy. Aiming to overcome the blood-brain barrier (BBB) limitations, one of the most promising approaches is the use of drug delivery systems (DDS) to treat the cancer cells in situ. Dacarbazine (DTIC) is an antitumor agent that has limited application given its high toxicity to healthy cells. However, it is effective against GB recurrent cells. In this study, DTIC polymeric nanofibers (NF) were successfully prepared, characterized and its in vitro anticancer efficacy was determined. This system demonstrated high drug loading of 83.9 ± 6.5%, good stability and mechanical properties and sustained drug release, improved in tumor pH (6.8). This controlled release prolonged the uptake of GB improving DTIC antitumor effects such as DNA damage and cell death by apoptosis. Molecular dynamics simulations revealed that DTIC interacts with PVA, possibly explaining the controlled release of the drug. Therefore, DTIC NF brain-implants show great potential as a promising drug delivery system for GB therapy.

Photochemically stabilized formulation of dacarbazine with reduced production of algogenic photodegradants.

The present study aimed to develop a photochemically stabilized formulation of dacarbazine [5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide; DTIC] for reducing the production of algogenic photodegradant (5-diazoimidazole-4-carboxamide; Diazo-IC). Photochemical properties of DTIC were characterized by UV-visible light spectral analysis, reactive oxygen species (ROS) assay, and photostability testing. A pharmacokinetic study was conducted after intravenous administration of DTIC formulations (1 mg-DTIC/kg) to rats. DTIC exhibited strong absorption in the UVA range, and photoirradiated DTIC exhibited marked ROS generation. Thus, DTIC had high photoreactive potential. After exposure of DTIC (1 mM) to simulated sunlight (250 W/m2) for 3 min, remaining DTIC and yielded Diazo-IC were estimated to be ca. 230 µM and 600 µM, respectively. The addition of radical scavenger (1 mM), including l-ascorbic acid, l-cysteine (Cys), l-histidine, D-mannitol, l-tryptophan, or l-tyrosine, to DTIC (1 mM) could attenuate DTIC photoreactions, and in particular, the addition of Cys to DTIC brought ca. 34% and 86% inhibition of DTIC photodegradation and Diazo-IC photogeneration, respectively. There were no significant differences in the calculated pharmacokinetic parameters of DTIC between DTIC and DTIC with Cys (0.67 mg/kg). From these findings, the supplementary use of Cys would be an effective approach to improve the photostability of DTIC with less production of Diazo-IC.

A peptide-modified solid lipid nanoparticle formulation of paclitaxel modulates immunity and outperforms dacarbazine in a murine melanoma model.

Melanoma is a highly aggressive skin cancer. A paclitaxel formulation of solid lipid nanoparticles modified with Tyr-3-octreotide (PSM) is employed to treat melanoma that highly expresses somatostatin receptors (SSTRs). PSM exerts more apoptotic and anti-invasive effects in B16F10 mice melanoma cells as compared to dacarbazine (DTIC), an approved chemotherapeutic drug for treating aggressive melanoma. Besides, PSM induces one of the biomarkers of immunogenic cell death in vitro and in vivo as confirmed by calreticulin exposure on the B16F10 cell surface. We observed a significant number of CD8 positive T cells in the tumor bed of the PSM treated group. As a result, PSM effectively reduces tumor volume in vivo as compared to DTIC. PSM also induces a favorable systemic immune response as determined in the spleen and sera of the treated animals. Importantly, PSM can reduce the number of nodule formations in the experimental lung metastasis model. Our experimentations indicate that the metronomic PSM exhibits remarkable anti-melanoma activities without any observable toxicity. This immune modulation behavior of PSM can be exploited for the therapy of melanoma and probably for other malignancies.

The carbonic anhydrase IX inhibitor SLC-0111 sensitises cancer cells to conventional chemotherapy.

Drug combination represents one of the most accredited strategies of cancer therapy able to improve drug efficacy and possibly overcome drug resistance. Among the agents used to complement conventional chemotherapy, carbonic anhydrase IX (CAIX) inhibitors appear as one of the most suitable, as markers of hypoxic and acidic cancer cells which do not respond to chemo- and radiotherapy. We performed preclinical in vitro assays to evaluate whether the SLC-0111 CAIX inhibitor co-operates and potentiates the cytotoxic effects of conventional chemotherapeutic drugs in A375-M6 melanoma cells, MCF7 breast cancer cells, and HCT116 colorectal cancer cells. Here, we demonstrate that the SLC-0111 CAIX inhibitor potentiates cytotoxicity of Dacarbazine and Temozolomide currently used for advanced melanoma treatment. SLC-0111 also increases breast cancer cell response to Doxorubicin and enhances 5-Fluorouracil cytostatic activity on colon cancer cells. These findings disclose the possibility to extend the use of CAIX inhibitors in the combination therapy of various cancer histotypes.

Aurora kinase B siRNA-loaded lactoferrin nanoparticles potentiate the efficacy of temozolomide in treating glioblastoma.

AIM: To investigate the efficacy of lactoferrin nanoparticles (LfNPs) in delivering siRNA across the blood-brain barrier to treat glioblastoma multiforme (GBM) and with an additional objective of potentiation of conventional temozolomide (TMZ) chemotherapy. METHODS: Aurora kinase B (AKB) siRNA-loaded nanoparticles (AKB-LfNPs) were prepared with milk protein, lactoferrin, by water in oil emulsion method. AKB-LfNPs were tested in cell lines and in GBM orthotopic mouse model with and without TMZ treatment. RESULTS: AKB silencing, cytotoxicity and cell cycle arrest by these LfNPs were shown to be effective on GL261 cells. Tumor growth was significantly lower in AKB-LfNPs alone and in combination with TMZ treated mice and increased the survival by 2.5-times. CONCLUSION: Treatment of AKB-LfNPs to GBM mice improves life expectancy and has potential to combine with conventional chemotherapy.

Temozolomide loaded nano lipid based chitosan hydrogel for nose to brain delivery: Characterization, nasal absorption, histopathology and cell line study.

The present study was designed to develop and optimize Temozolomide nano lipid chitosan hydrogel formulations (TMZNLCHG) to target the brain through nasal route. The formulation was developed using chitosan as a gelling agent and Vit E: gelucire 44/14 blend as lipid. The formulations were evaluated for particle size, encapsulation efficiency (%EE), drug loading (DL), morphology, drug release, nasal diffusion, cell line study, and histopathology study. The particle size, PDI, %EE, %DL, and drug release were found to be 134 nm, 0.177, 88.45% ±â€¯4.45%, 9.12% ±â€¯0.78%, and 84.23% ±â€¯2.78%, respectively. The enhancement ratio was more than two folds higher than TMZCHG formulation (control) suggesting the superiority of chitosan with lipid as permeability enhancer. The microscopic image of lyophilized TMZNLCHGopt displayed the spherical and rough surface morphology. IC50 was found to be 3.34 µg/ml for TMZNLCHGopt and was 160 µg/ml for pure TMZ. Further, No structural damage was observed with TMZNLCHGopt treated nasal mucosa upon histopathological examination. Overall, the present study produces encouraging findings in the formulation of a non-invasive intranasal route for brain targeting as an alternate to other route for TMZ.

Receptor-mediated PLGA nanoparticles for glioblastoma multiforme treatment.

Glioblastoma multiforme is the most lethal type of brain tumor and the established therapy only extends patients survival to approximately one year. Its first-line treatment is based on of chemotherapy with the alkylating agent temozolomide (TMZ). As many other chemotherapeutic drugs, TMZ presents several limitations as high toxicity and low bioavailability. The delivery of TMZ using poly(lactic-co-glycolic acid) nanoparticles is proposed in this work. Stable nanoparticles functionalized with a OX26 type monoclonal antibody for transferrin receptor were developed, targeting the glioblastoma tumor cells, since these cells are known for overexpressing this receptor. The release profile of TMZ from the nanoparticles was studied mimicking physiological conditions, and targeted cellular internalization was also investigated. Two glioblastoma cell lines - U215 and U87 - were used to evaluate the in vitro cytotoxicity of the drug, showing that the prepared nanocarriers enhance the anticancer activity of TMZ. The functionalization with the monoclonal antibody for transferrin receptor proved to be advantageous in enhancing the cellular internalization in glioblastoma cells.

Magnetic core mesoporous silica nanoparticles doped with dacarbazine and labelled with 99mTc for early and differential detection of metastatic melanoma by single photon emission computed tomography.

Cancer is responsible for more than 12% of all causes of death in the world, with an annual death rate of more than 7 million people. In this scenario melanoma is one of the most aggressive ones with serious limitation in early detection and therapy. In this direction we developed, characterized and tested in vivo a new drug delivery system based on magnetic core-mesoporous silica nanoparticle that has been doped with dacarbazine and labelled with technetium 99 m to be used as nano-imaging agent (nanoradiopharmaceutical) for early and differential diagnosis and melanoma by single photon emission computed tomography. The results demonstrated the ability of the magnetic core-mesoporous silica to be efficiently (>98%) doped with dacarbazine and also efficiently labelled with 99mTc (technetium 99 m) (>99%). The in vivo test, using inducted mice with melanoma, demonstrated the EPR effect of the magnetic core-mesoporous silica nanoparticles doped with dacarbazine and labelled with technetium 99 metastable when injected intratumorally and the possibility to be used as systemic injection too. In both cases, magnetic core-mesoporous silica nanoparticles doped with dacarbazine and labelled with technetium 99 metastable showed to be a reliable and efficient nano-imaging agent for melanoma.

NKG2D ligands in glioma stem-like cells: expression in situ and in vitro.

Glioblastoma multiforme (GBM) is a highly malignant brain tumor. Tumor stem cells have a major influence on tumor malignancy, and immunological escape mechanisms, involving the Natural Killer Group 2, member D (NKG2D) receptor-ligand-system, are key elements in tumor immuno-surveillance. We analyzed the expression profile and localization of NKG2D ligands (NKG2DL) and embryonic and neural stem cell markers in solid human GBM and stem-like cells isolated from glioma cell lines by qRT-PCR and immunohistochemistry, including quantitative analysis. We also evaluated the effect of Temozolomide (TMZ), the standard chemotherapeutic agent used in GBM therapy, on NKG2DL expression. NKG2DL-positive cells were mostly found scattered and isolated, were detectable in glial fibrillary acidic protein (GFAP)-positive tumor regions and partly in the penumbra of tumor vessels. NKG2DL were found in a distinct tumor stem-like cell subpopulation and were broadly costained with each other. Quantitative analysis revealed, that dependent on the individual NKG2DL investigated, cell portions costained with different stem cell markers varied between small (Musashi-1) and high (KLf-4) amounts. However, a costaining of NKG2DL with CD3γ, typically found in T cells, was also observable, whereas CD11b as a marker for tumor micoglia cells was only rarely costained with NKG2DL. Stem-like cells derived from the glioma cell lines T98G and U251MG showed a distinct expression pattern of NKG2DL and stem cell markers, which seemed to be balanced in a cell line-specific way. With differentiation, T98G displayed less NKG2DL, whereas in U251MG, only expression of most stem cell markers decreased. In addition, stimulation with TMZ led to a significant upregulation of NKG2DL in stem-like cells of both lines. As stem-like glioma cells tend to show a higher expression of NKG2DL than more differentiated tumor cells and TMZ treatment supports upregulation of NKG2DL, the NKG2D system might play an important role in tumor stem cell survival and in GBM therapy.

Solid Lipid Nanoparticles Carrying Temozolomide for Melanoma Treatment. Preliminary In Vitro and In Vivo Studies.

AIM: To develop an innovative delivery system for temozolomide (TMZ) in solid lipid nanoparticles (SLN), which has been preliminarily investigated for the treatment of melanoma. MATERIALS AND METHODS: SLN-TMZ was obtained through fatty acid coacervation. Its pharmacological effects were assessed and compared with free TMZ in in vitro and in vivo models of melanoma and glioblastoma. RESULTS: Compared to the standard free TMZ, SLN-TMZ exerted larger effects, when cell proliferation of melanoma cells, and neoangiogeneis were evaluated. SLN-TMZ also inhibited growth and vascularization of B16-F10 melanoma in C57/BL6 mice, without apparent toxic effects. CONCLUSION: SLN could be a promising strategy for the delivery of TMZ, allowing an increased stability of the drug and thereby its employment in the treatment of aggressive malignacies.

Chitosan Engineered PAMAM Dendrimers as Nanoconstructs for the Enhanced Anti-Cancer Potential and Improved In vivo Brain Pharmacokinetics of Temozolomide.

PURPOSE: To establish a platform for the possibility of effective and safe delivery of Temozolomide (TMZ) to brain via surface engineered (polyamidoamine) PAMAM dendrimer for the treatment of glioblastoma. METHODS: The present study aims to investigate the efficacy of PAMAM-chitosan conjugate based TMZ nanoformulation (PCT) against gliomas in vitro as well as in vivo. The prepared nanoconjugated formulation was characterized by 1H NMR, FT-IR spectroscopy and for surface morphological parameters. The reported approach was also designed in such a way to ensure toxicity before in vivo delivery through conducting the hemolytic study. RESULT: Surface morphology was found as per nanoformulation via size, pdi and zeta potential measurement. PCT was more efficacious in terms of IC50 values compared to pure TMZ against U-251 and T-98G glioma cell lines. The in vivo pharmacokinetic parameters proved sustained release fashion such as half-life (t1/2) of 22.74 h (PCT) rather than15.35 h (TMZ) only. Higher concentration was found in heart than brain in bio-distribution studies. This study exhibits the potential applicability of dendrimer and CS in improving the anticancer activity and delivery of TMZ to brain. CONCLUSION: The attractive ex vivo cytotoxicity against two glioma cell lines; U-251 and T-98G and phase solubility studies of TMZ revealed remarkable results. In vivo studies of prepared nanoformulation were significant and promising that explored the double concentration of TMZ in brain due to surface functionality of dendrimer. The reported work is novel and non- obvious as none of such approaches using chitosan anchored dendrimer for TMZ delivery has been reported earlier.

Formulation and statistical optimization of intravenous temozolomide-loaded PEGylated liposomes to treat glioblastoma multiforme by three-level factorial design.

The aim of the presented study was to develop PEGylated liposomes of Temozolomide (TMZ) that provide optimum drug concentration at tumor site. Reverse phase evaporation (REV) method was used to prepare TMZ-loaded PEGylated liposomes. Formulation was optimized by using design expert software by 32 factorial design. The physicochemical properties including size, morphology, entrapment efficiency, drug loading, etc. of formulated liposomes were evaluated. Finally, the optimized formulation was selected for in vitro drug release and stability study. In vivo pharmacokinetic study in rats showed that TMZ-loaded PEGylated liposomes leads to 1.6-fold increase in AUCTotal in blood and 4.2-fold increase in brain as compared to free drug solution. This formulated PEGylated liposomes offers a promising approach for treatment of Glioblastoma Multiforme.

Development of temozolomide coated nano zinc oxide for reversing the resistance of malignant glioma stem cells.

Recently most of the researchers have turned their interest towards plant mediated synthesis of metal nanoparticles to avoid several environmental toxicants. In this manuscript, we have discussed the ecofriendly syntheses of zinc oxide nanoparticles (ZnO NPs) were achieved using Glycyrrhiza glabra (G. glabra) seed aqueous extract. The green synthesized ZnO NPs were characterized using analytical techniques like XRD, TEM, particle size histogram and Zeta potential. From the results, it was found that the green synthesized ZnO NPs were around 35nm in size with irregular spherical shape. The Zeta potential study of ZnO NPs was resulted to be high stabile with electronegative charge around -56.3mV. Further the G. glabra seed aqueous extract mediated synthesis of ZnO NPs were subjected to treat human glioblastoma cells with the help of temozolomide (TMZ) a commercially available drug by the method of MTT cell viability assay. The results stated that the ZnO NPs shows IC50 value around 30µg/mL results significantly. The plausible mechanism behind the mortality rate was also discussed in this manuscript.

Dacarbazine nanoparticle topical delivery system for the treatment of melanoma.

Dacarbazine (DZ) is poorly soluble in water with the short half-life in blood circulation, low rate of response with the toxic effect which ultimately limits its utilization of the treatment of skin cancer. In view of this background current study was designed for development of dacarbazine laden nanoparticle (DZNP) and dacarbazine laden nanocream (DZNC) topical delivery system for the treatment of melanoma. Firstly DZNP was prepared. By using DZNP its cream formulation prepared for topic drug delivery for melanoma. Dacarbazine nanoparticle and its cream were evaluated for morphology, drug load capacity, efficiency of nanoencapsulation and size of particle and zeta potential, Transmission Electron Microscopy (TEM), determination of pH, spreadability and viscosity, in vitro drug release capacity and its cytotoxic potential. The particle size of DZNP and DZNC was 16.3 ± 8.1 nm and 16.9 ± 7.8 nm respectively. pH value and spreadability of nanoparticle cream were found to be 6.7 ± 0.14 g cm/sec and 55.23 ± 3.13 g cm/sec respectively. Nanoencapsulation efficiency and Drug loading capacity were 67.4 ± 3.5% and 6.73 mg/10 mg respectively. IC50 of dacarbazine nanoparticle was 0.19 mg/ml while it was 0.63 mg/ml for nanoparticle cream. It can be concluded that DZNP and its cream can be effectively used as a topical formulation for the treatment of melanoma.

The use of TMZ embedded hydrogels for the treatment of orthotopic human glioma xenografts.

The current treatment of glioblastoma multiforme (GBM) is limited by the restricted arsenal of agents which effectively cross the blood brain barrier (BBB). For example, only a fraction of temozolomide (TMZ) administered systemically is available for therapeutic effect because of the BBB and the instability of TMZ under physiologic conditions. A novel approach to overcome this obstacle is to bypass the BBB and locally deliver chemotherapeutic agents directly to the tumor mass. We have explored the loading of TMZ into a novel hydrogel matrix, which can be delivered in liquid form and then solidifies in situ and releases chemotherapy as the matrix dissolves. Here, we tested the effect of amphiphilic diblock copolypeptide hydrogels (DCHs) of 180-poly-lysine and 20-poly-leucine (K180L20) on TMZ using Glioblastoma models. In both the in vitro model, which involved treatment of a human glioblastoma GSC line suspended as neurospheres, and in vivo using an orthotopic glioma xenograft mouse model, we found that K180L20 could safely enhance the efficacy of TMZ. This technique may offer the opportunity to 'coat' the inner lining of the cavity following glioma resection with a slow-release TMZ and potentially decrease recurrence. Future studies in larger animals are needed to delineate this effect.

Acyclic cucurbit[n]uril conjugated dextran for drug encapsulation and bioimaging.

An acyclic cucurbit[n]uril (CB[n]) conjugated dextran is developed as a new biomaterial for drug delivery and bioimaging. This biomaterial retains the host-guest recognition properties of acyclic CB[n]s. It is able to directly encapsulate anti-tumor drugs 5-fluorouracil and temozolomide. This polymeric material can form a supramolecular assembly with polyethyleneimine (PEI). Although there is no conventional chromophore in these supramolecular systems, they exhibit aggregation-induced emission (AIE) in water with a quantum yield of 10%. This supramolecular assembly is used for bioimaging in vitro with good biocompatibility.