Pomegranate extract-loaded sphingosomes for the treatment of cancer: Phytochemical investigations, formulation, and antitumor activity evaluation

AIM

Formulation of Pomegranate Extracts (PE)-loaded sphingosomes as an antitumor therapy for the intravenous and passive targeted delivery to various tumor types, especially that of the breast, colon, and uterus; to increase the therapeutic activity and decrease the adverse effects profile.

METHODS

The pericarp and seeds' juice of Punica granatum were each extracted using D.W. and ethanol. Phytochemical investigation of all extracts was carried out including total phenolics, flavonoids, and anthocyanins contents, the antioxidant activity, as well as HPLC analysis of phenolics and flavonoids. The antitumor potential of all extracts was also tested utilizing three cell lines: MCF-7, HeLa, and HCT116. The candidate extract was chosen for the formulation phase and was entrapped into the sphingosomes using the thin-film hydration method and employing three different PE: lipids weight ratios. The synthesized formulations were characterized for their size, morphological features, zeta potential, entrapment efficiency, and in vitro drug release and kinetics modeling studies. The optimized formula was further analyzed by FTIR spectroscopy and electron microscopy. The antitumor activity of F2 was also investigated using the same cancer cell lines compared to the plant extract.

RESULTS

The highest phenolics, flavonoids, and anthocyanins contents were observed in the ethanolic pericarps extract (EPE), followed by the ethanolic seeds extract (ESE). Consequently, EPE showed a higher antitumor activity hence it was selected for the formulation phase. PE-loaded sphingosomes formula (F2) was selected for having the highest EE% (71.64%), and a sustained release profile with the highest in vitro release (42.5±9.44%). By employing the DDSolver, the Weibull model was found the most suitable to describe the PE release kinetics compared to other models. The release mechanism was found to follow Fickian diffusion. Simulated pharmacokinetic parameters have portrayed F2 as the candidate formula, with the highest AUC (536.095) and slowest MDT (0.642 h). In addition, F2 exhibited a significant (p>0.05) stronger and prolonged anticancer effect against MCF-7, HeLa, and HCT116 cell lines at all concentrations tested compared to the free extract.

CONCLUSION

The results proved that sphingosomes are an effective delivery system, improving pharmacological efficacy and reducing serious side effects of anticancer medications and natural products.

Assessment of Oxaliplatin-Loaded Iodine Nanoparticles for Chemoradiotherapy of Human Colorectal Cancer (HT-29) Cells

Colorectal cancer is highly prevalent worldwide and has significant morbidity and mortality in humans. High-atomic-number nanoparticles such as iodine can act as X-rays absorbers to increase the local dose. The synthesis and fabrication of oxaliplatin-loaded iodine nanoparticles, their characterization, cell toxicity, radiosensitivity, cell apoptosis, and cell cycle assay in human colorectal cancer (HT-29) cells are investigated. Results show that the synthesis of a new iodine nanoparticle, polymerized triiodobenzene coated with chitosan and combined with oxaliplatin as a chemotherapeutic drug, performed well in vitro in an intracellular radiosensitizer as chemoradiotherapy agent in HT-29 cell lines. Findings also show that the INPs alone have no impact on cell cycle development and apoptosis. In contrast, oxaliplatin-loaded INPs along with 2 and 6 MV radiation doses produced more apoptosis. The interaction of INPs with mega-voltage photon energies is the cause of a major radiosensitization enhancement in comparison to radiation alone. Furthermore, results show that INPs may work as radiosensitization nanoprobe agents in the treatment of HT-29 cells due to their effect on increasing radiation dose absorption. Overall, iodine nanoparticles may be used in the treatment of colorectal cancers in clinical studies.

Co-delivery of Doxorubicin and Ceramide in a Liposomal Formulation Enhances Cytotoxicity in Murine B16BL6 Melanoma Cell Lines

This study reports co-delivery of doxorubicin (DOX) and ceramide in a liposomal system in B16BL6 melanoma cell lines for enhanced cytotoxic effects. Different types of ceramides (C6-ceramide, C8-ceramide, and C8-glucosylceramide) and lipids (1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE)) were considered in the preparation of liposomes. DOX was encapsulated within liposome, and ceramide was used as the component of the lipid bilayer. The formulations were optimized for size and size distribution, zeta potential, and DOX encapsulation efficiency (EE). Cytotoxic effect on B16BL6 melanoma cell lines was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The ceramide based liposome formulations generally provided a mean diameter < 181 nm, a zeta potential, + 35 mV, and EE > 90% DOX EE. Co-delivery of DOX and C8-ceramide with DOTAP liposomes demonstrated significantly higher cytotoxicity as compared to DOX liposomes without ceramide (P < 0.001), and also showed enhanced cellular uptake by B16BL6 cell lines. This study provides basis for developing a co-delivery system of DOX and ceramide for lowering the dose and dose-related side effects of DOX for the treatment of melanoma.

Molecular efficacy of radio- and chemotherapy sequences from direct DNA damage measurements

PURPOSE

To investigate the molecular aspects of the synergy between ionizing radiation and platinum (Pt) chemotherapeutic agents in cancer treatment with chemoradiation therapy (CRT) by measuring damages induced by low-energy electrons (LEE) to DNA bound to cisplatin. LEE are produced abundantly by any type of ionizing radiation and cisplatin represents a typical Pt-chemotherapeutic agents.

MATERIALS AND METHODS

Our strategy involves two parallel administrations of cisplatin and irradiation with a 4.6 and 9.6 eV electron fluence of 1.1 × 10¹²: (1) LEE bombardment of supercoiled DNA and its subsequent reaction with cisplatin; (2) the reaction of DNA with cisplatin followed by LEE irradiation. The damage yields for the loss of supercoiled (LS), single-strand breaks (SSB) and double-strand breaks (DSB) were obtained from gel electrophoresis analysis. Base modifications were revealed by treating the samples with Escherichia coli base excision repair endonuclease (Nth and Fpg).

RESULTS

The yields were deduced from the respective time-response for the reaction of DNA with cisplatin. The results show that binding cisplatin to DNA followed by LEE irradiation, consistently yields more DNA damages than the reverse order. In comparison to non-treated DNA, administration (2) results in an increase of LS and SSB of 1.4-3.3 folds and of DSB by more than an order of magnitude. Furthermore, after enzyme treatment, the yields of DSB rise by factors of 5.3-15.4, indicating a large increase of clustered damages, which should at least partially translate into an increase of lethal damages in cancer cells during the CRT.

CONCLUSIONS

Our results demonstrate that a strong synergy between radiation and cisplatin can only be achieved at the molecular level, if the drug is present at the time of irradiation. Furthermore, this work confirms the LEE mechanism previously proposed to explain the synergy between radiation and Pt drugs in CRT. It involves chemical sensitization of DNA prior to irradiation, to facilitate strand breaks and clustered damages induced by the highly reactive LEE.

Novel Instruments for the Implementation of Electrochemotherapy Protocols: From Bench Side to Veterinary Clinic

Electrochemotherapy (ECT) is a medical strategy that allows an increased efficacy of chemotherapy agents after the application of permeabilizing electric pulses having appropriate characteristics (form, voltage, frequency). In the past 10 years, the clinical efficacy of this therapeutic approach in several spontaneous models of tumors in animals has been shown. Moreover, some of the molecular and cellular mechanisms responsible for this phenomenon have been elucidated. Our group has been deeply involved in the development of new ECT protocols for companion animals, implementing the use of the technique as first line treatment, and evaluating different chemotherapy agents in laboratory animals as well as pets. This article summarizes the most important advances in veterinary ECT, including the development of novel equipment, therapeutic protocols, and their translation to humans. J. Cell. Physiol. 232: 490-495, 2017. © 2016 Wiley Periodicals, Inc.

Thermosensitive Hydrogel Co-loaded with Gold Nanoparticles and Doxorubicin for Effective Chemoradiotherapy

Chemoradiotherapy, as a well-established paradigm to treat various cancers, still calls for novel strategies. Recently, gold nanoparticles (AuNPs) have been shown to play an important role as a radiosensitizer in cancer radiotherapy. The aim of this study was to evaluate the combination of polyethylene glycol (PEG) modified AuNPs and doxorubicin (DOX) to improve cancer chemoradiotherapy, in which the AuNPs was the radiosensitizer and the DOX was the model chemotherapeutic. A Pluronic® F127-based thermosensitive hydrogel (Au-DOX-Gel) loading AuNPs and DOX was developed by "cold method" for intratumoral injection. The formulation was optimized at a F127 concentration of 22% for Au-DOX-Gel. The release profiles compared to a control group were assessed in vitro and in vivo. Au-DOX-Gel showed sustained release of AuNPs and DOX. The cell viability and surviving fraction of mouse melanoma (B16) and Human hepatocellular liver carcinoma (HepG2) cells were significantly inhibited by the combination treatment of DOX and AuNPs under radiation. Tumor sizes of mice were significantly decreased by Au-DOX-Gel compared to controls. Interestingly, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and Ki-67 staining results showed that tumor cell growth and proliferation were inhibited by AuNPs combined with DOX under radiation, suggesting that the radiosensitization activity and combination effects might be caused by inhibition of tumor cell growth and proliferation. Furthermore, the results of skin safety tests, histological observation of organs, and the body weight changes indicated in vivo safety of Au-DOX-Gel. In conclusion, the Au-DOX-Gel developed in this study could represent a promising strategy for improved cancer chemoradiotherapy.

Biological effects of irradiating hepatocellular carcinoma cells by internal exposure with 125I-labeled 5-iodo-2'-deoxyuridine-chitosan drug loading nanoparticles

In this study, the authors evaluate the biological effects of irradiation of hepatocellular carcinoma cells by internal exposure with (125)I-labeled 5-iodo-2'-deoxyuridine ((125)I-UdR)-chitosan drug loading nanoparticles ((125)I-UdR-CS-DLN). The authors observed that accumulation of nanoparticles was significantly (p<0.05) higher in hepatocellular carcinoma cells HepG2 than normal liver cells HL-7702 after treated with (125)I-UdR-CS-DLN for 30 minutes. Survival of HepG2 cells was significantly lower at (125)I-UdR-CS-DLN doses higher than 37 kBq/mL (more significant in the G1 phase and G2/M phase) than the HL-7702 cells. In addition, (125)I-UdR-CS-DLN induced a higher level of DNA double-strand breaks than (125)I-UdR, and HepG2 cells exhibited a lower level of DNA repair when compared with HL-7702 cells. In vivo animal experiments, TUNEL staining, after targeted treatment, showed that (125)I-UdR-CS-DLN induced significant cell apoptosis in rabbit hepatocellular tumors in situ than (125)I-UdR infusion at the same dose. In conclusion, hepatocellular carcinoma cells were significantly irradiated with (125)I-UdR-CS-DLN compared with (125)I-UdR, and (125)I-UdR-CS-DLN irradiation enhanced DNA damage, induced liver cancer cell apoptosis, and prevented DNA damage repair. However, evaluating the extent of damage and organ sparing in vivo should also be considered.