Combinatorial Effect of Doxorubicin Entrapped in Alginate-Chitosan Hybrid Polymer and Cerium Oxide Nanocomposites on Skin Cancer Management in Mice

Conventional chemotherapeutic drugs are used for cancer management, but recently nanoparticles have also been shown to contribute towards controlling cancer cell proliferation. In the present study, we focussed on analyzing the combinatorial effect of Cerium oxide (CeO2) nanoparticles and Doxorubicin (Dox) on melanoma cancer cells in vitro and in vivo. We entrapped CeO2, Dox, and CeO2+Dox in a hybrid polymer matrix of alginate and chitosan (Alg-Cs) and used them in both in vitro and in vivo studies to compare their anticancer effect. Scratch assay using A549 lung cancer cells showed delayed wound healing when exposed to a low and high dose of CeO2 +Dox, compared to individual components. In order to determine a safe dose of the nanoformulations, zebrafish embryos were used. Further, in vivo, testing was done on Swiss albino female mice where the melanoma was induced by applying Benzopyrene followed by UV irradiation. The animals were treated with CeO2, Dox, and CeO2+ Dox that were entrapped in Alg-Cs for further 21 days. From both in vivo and in vitro results, we concluded that CeO2 and Dox in combination had superior therapeutic efficiency in cancer cells and animals than the nude drugs.

Naringin sensitizes the antibiofilm effect of ciprofloxacin and tetracycline against Pseudomonas aeruginosa biofilm

The study aims to explore the combinatorial effect of naringin with antibiotics, ciprofloxacin and tetracycline on Pseudomonas aeruginosa biofilms. The antibiofilm efficacy of selected treatment regimes against P. aeruginosa biofilm were quantified by crystal violet assay, MTT assay, Congo red binding assay, and were visualized by confocal laser scanning microscopy and scanning electron microscopy. All the assays reflected antibiofilm activities, however, combinatorial performances of naringin with antibiotics were found to be more significant. A significant reduction in swimming and swarming motilities along with pellicle formation and altered colony morphology were observed as a result of combinatorial effect. The cytotoxicity of naringin and its antibiotic combinations was assayed on murine macrophage cell line. The applicability of such combinations was tested for their relative eradication against pre-formed biofilm on urinary catheter surface. This finding indicated that naringin potentiates the efficacy of both ciprofloxacin and tetracycline on P. aeruginosa biofilm in comparison to their solo treatment. The finding would help to open hitherto unexplored possibilities of establishing naringin as a potential antibiofilm agent and suggest on the possibility of its use in drug-herb combinations for managing biofilm-associated bacterial infections.

Analysis of polymorphisms in RIG-I-like receptor genes in German multiple sclerosis patients

Variation in genes encoding retinoid acid-inducible gene I (RIG-I)-like receptors (RLRs) has been implicated in the pathogenesis of autoimmune disorders. We investigated if polymorphisms in the IFIH1, RIG-I, LGP2 and VISA genes influence the risk for multiple sclerosis (MS) in a German case-control cohort comprising 716 patients and 706 controls. Evaluation of 18 single nucleotide polymorphisms (SNPs) in the four genes did not reveal significant single-SNP associations with MS risk, but two VISA polymorphisms were modestly associated with age of onset. Further, we provide initial evidence for combinatorial effects of polymorphic variants in the RIG-I, LGP2 and IFIH1 genes on MS risk.

Potent drugs that attenuate anti-Candida albicans activity of fluconazole and their possible mechanisms of action

Fluconazole (FLCZ) is a first-line drug for treating Candida albicans infections, but clinical failure due to reduced sensitivity is a growing concern. Our previous study suggested that certain drug combinations pose a particular challenge in potently reducing FLCZ's anti-C. albicans activity, and cyclooxygenase inhibitors formed the major group of these attenuating drugs in combination with FLCZ. In this study, we examined the effects of diclofenac sodium (DFNa) and related compounds in combination with FLCZ against C. albicans, and investigated their possible mechanisms of interaction. DFNa, ibuprofen, and omeprazole elevated the minimum inhibitory concentration (MIC) of FLCZ by 8-, 4-, and 4-fold, respectively; however, loxoprofen sodium and celecoxib did not. An analogue of DFNa, 2,6-dichlorodiphenylamine, also elevated the MIC by 4-fold. Gene expression analysis revealed that diclofenac sodium induced CDR1 efflux pump activity, but not CDR2 activity. In addition, an efflux pump CDR1 mutant, which was manipulated to not be induced by DFNa, showed less elevation of MIC compared to that shown by the wild type. Therefore, DFNa and related compounds are potent factors for reducing the sensitivity of C. albicans to FLCZ partly via induction of an efflux pump. Although it is not known whether such antagonism is relevant to the clinical treatment failure observed, further investigation of the molecular mechanisms underlying the reduction of FLCZ's anti-C. albicans activity is expected to promote safer and more effective use of the drug.

Combinatorial effects of amoxicillin and metronidazole on selected periodontal bacteria and whole plaque samples

OBJECTIVE

The aim of the present study was to analyze in vitro the combinatorial effects of the antibiotic combination of amoxicillin plus metronidazole on subgingival bacterial isolates.

DESIGN

Aggregatibacter (Actinobacillus) actinomycetemcomitans, Prevotella intermedia/nigrescens, Fusobacterium nucleatum and Eikenella corrodens from our strain collection and subgingival bacteria isolated from patients with periodontitis were tested for their susceptibility to amoxicillin and metronidazole using the Etest. The fractional inhibitory concentration index (FICI), which is commonly used to describe drug interactions, was calculated.

RESULTS

Synergy, i.e. FICI values ≤ 0.5, between amoxicillin and metronidazole was shown for two A. actinomycetemcomitans (FICI: 0.3), two F. nucleatum (FICI: 0.3 and 0.5, respectively) and one E. corrodens (FICI: 0.4) isolates. Indifference, i.e. FIC indices of >0.5 but ≤4, occurred for other isolates and the 14 P. intermedia/nigrescens strains tested. Microorganisms resistant to either amoxicillin or metronidazole were detected in all samples by Etest.

CONCLUSION

Combinatorial effects occur between amoxicillin and metronidazole on some strains of A. actinomycetemcomitans, F. nucleatum and E. corrodens. Synergy was shown for a few strains only.

PBOX-15 induces apoptosis and improves the efficacy of oxaliplatin in human colorectal cancer cell lines

An emerging new class of targeted therapeutic molecules against the enzyme fatty acid amide hydrolase (FAAH) is a novel series of pyrrolo-1,5-benzoxa(thia)zepine compounds. A member of this family, pyrrolo-1,5-benzoxazepine-15 (PBOX-15), is a tubulin depolymerizing agent displaying a proapoptotic activity in a variety of human tumor cell types, including those derived from both solid and hematological malignancies, with minimal toxicity towards normal blood and bone marrow cells. In this study, we evaluated the PBOX-15-mediated effects in human colorectal cancer cell (CRC) lines. The compound, used at doses equal to or greater than 1 μM inhibits the proliferation of human CRC cell lines in a dose- and time-dependent manner, inducing a significant cell cycle arrest in the G2/M phase. DNA fragmentation assays and western blot analysis demonstrated that treatments prolonged over 48 h triggered a strong activation of the intrinsic apoptotic pathway as indicated by activation of caspase-3, caspase-9 and PARP. Moreover, nanomolar doses of PBOX-15, unable to cause microtubule depolymerization, significantly improved the oxaliplatin and 5-fluouracil-induced anti-proliferative effects in CRC cell lines. These results showed, for the first time, that PBOX-15 represents a promising compound for the treatment of human CRC and a strong candidate for novel therapeutic options.