Publications by authors named "Katharine Carter"

31 Publications

Drug combinations as effective anti-leishmanials against drug resistant .

RSC Med Chem 2020 Aug 2;11(8):905-912. Epub 2020 Jul 2.

University of the West of Scotland Paisley Campus , UK . Email:

is a parasite that causes the disease leishmaniasis, and 700 000 to 1 million new cases occur each year. There are few drugs that treat the disease and drug resistance in the parasite limits the clinical utility of existing drugs. One way to combat drug resistance is to use combination therapy rather than monotherapy. In this study we have compared the effect of single and combination treatments with four different compounds, alkylphosphocholine analogues APC12 and APC14, miltefosine (MIL), ketoconazole (KTZ), and amphotericin B (AmpB), on the survival of wild-type promastigotes and a cell line derived from the WT with induced resistance to APC12 (C12Rx). The combination treatment with APC14 and APC16 had a synergistic effect in killing the WT while the combination treatment with KTZ and APC12 or APC14 or APC12 and APC14 had a synergistic effect against C12Rx. More than 90% killing efficiency was obtained using APC12 alone at >1 mg ml against the C12Rx strain; however, combinations with APC14 produced a similar killing efficiency using APC12 at 0.063-0.25 mg ml and APC14 at 0.003-0.5 mg ml. These results show that combination therapy can negate induced drug resistance in and that the use of this type of screening system could accelerate the development of drug combinations for clinical use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0md00101eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7651635PMC
August 2020

Retraction Note: The melanocortin signaling cAMP axis accelerates repair and reduces mutagenesis of platinum-induced DNA damage.

Sci Rep 2021 Jan 7;11(1):847. Epub 2021 Jan 7.

The Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky, 40536, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-80467-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7791111PMC
January 2021

Antileishmanial efficacy and tolerability of combined treatment with non-ionic surfactant vesicle formulations of sodium stibogluconate and paromomycin in dogs.

Exp Parasitol 2021 Jan 7;220:108033. Epub 2020 Nov 7.

Cátedra de Farmacología, Facultad de Veterinaria, Universidad Complutense de Madrid, Avenida Puerta del Hierro s/n, Ciudad Universitaria, 28040, Madrid, Spain.

Infection with Leishmania infantum causes the disease visceral leishmaniasis (VL), which is a serious clinical and veterinary problem. The drugs used to treat canine leishmaniasis (CanL) do not cause complete parasite clearance; they can be toxic, and emerging drug resistance in parasite populations limits their clinical utility. Therefore, in this study we have evaluated the toxicity and efficacy of joint treatment with a 1:1 mixture of sodium stibogluconate-NIV (SSG-NIV, 10 mg Sb/day) and paromomycin-NIV (PMM-NIV, 10 mg PMM/kg/day), given intravenously daily for seven days from day 270 post-infection, to nine-month-old female beagle dogs (n = 6) experimentally infected with Leishmania infantum. Treatment significantly improved the clinical symptoms of VL infection in all the treated dogs, reduced parasite burdens in lymph nodes and bone marrow, and all symptomatic treated dogs, were asymptomatic at 90 days post-treatment. Treatment was associated with a progressive and significant decrease in specific IgG anti-Leishmania antibodies using parasite soluble antigen (p < 0.01) or rK39 (p < 0.01) as the target antigen. In addition, all dogs were classified as parasite negative based on Leishmania nested PCR and quantitative real time PCR tests and as well as an inability to culture of promastigote parasites from lymph nodes and bone marrow tissue samples taken at day 90 post-treatment. However, treatment did not cure the dogs as parasites were detected at 10 months post-treatment, indicating that a different dosing regimen is required to cause long term cure or prevent relapse.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.exppara.2020.108033DOI Listing
January 2021

Structure and Antiparasitic Activity Relationship of Alkylphosphocholine Analogues against .

Microorganisms 2020 Jul 24;8(8). Epub 2020 Jul 24.

Institute of Biomedical and Environmental Health Research, University of the West of Scotland School of Science and Sport High Street Paisley, Scotland PA1 2BE, UK.

Miltefosine (Milt) is the only oral treatment for visceral leishmaniasis (VL) but its use is associated with adverse effects, e.g., teratogenicity, vomiting, diarrhoea. Understanding how its chemical structure induces cytotoxicity, whilst not compromising its anti-parasitic efficacy, could identify more effective compounds. Therefore, we systemically modified the compound's head, tail and linker tested the in vitro activity of three alkylphosphocholines (APC) series against strains with different sensitivities to antimony. The analogue, APC12, with an alkyl carbon chain of 12 atoms, was also tested for anti-leishmanial in vivo activity in a murine VL model. All APCs produced had anti-leishmanial activity in the micromolar range (IC and IC, 0.46- > 82.21 µM and 4.14-739.89 µM; 0.01- > 8.02 µM and 0.09-72.18 µM, respectively, against promastigotes and intracellular amastigotes). The analogue, APC12 was the most active, was 4-10 fold more effective than the parent Milt molecule (APC16), irrespective of the strain's sensitivity to antimony. Intravenous administration of 40 mg/kg APC12 to infected BALB/c mice reduced liver and spleen parasite burdens by 60 ± 11% and 60 ± 19%, respectively, while oral administration reduced parasite load in the bone marrow by 54 ± 34%. These studies confirm that it is possible to alter the Milt structure and produce more active anti-leishmanial compounds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/microorganisms8081117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7463460PMC
July 2020

Can We Harness Immune Responses to Improve Drug Treatment in Leishmaniasis?

Microorganisms 2020 Jul 17;8(7). Epub 2020 Jul 17.

Department of Molecular and Cell Biology, University of Cape Town, Cape Town 7925, South Africa.

Leishmaniasis is a vector-borne parasitic disease that has been neglected in priority for control and eradication of malaria, tuberculosis, and HIV/AIDS. Collectively, over one seventh of the world's population is at risk of being infected with 0.7-1.2 million new infections reported annually. Clinical manifestations range from self-healing cutaneous lesions to fatal visceral disease. The first anti-leishmanial drugs were introduced in the 1950's and, despite several shortcomings, remain the mainstay for treatment. Regardless of this and the steady increase in infections over the years, particularly among populations of low economic status, research on leishmaniasis remains under funded. This review looks at the drugs currently in clinical use and how they interact with the host immune response. Employing chemoimmunotherapeutic approaches may be one viable alternative to improve the efficacy of novel/existing drugs and extend their lifespan in clinical use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/microorganisms8071069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409143PMC
July 2020

Examination of the effect of niosome preparation methods in encapsulating model antigens on the vesicle characteristics and their ability to induce immune responses.

J Liposome Res 2021 Jun 28;31(2):195-202. Epub 2020 May 28.

Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom.

Niosome nanoparticles can be prepared using different methods, each of which can affect the size and homogeneity of the prepared particles. The aim of this study was to establish if the method of preparation impacted on the prepared vesicles when loaded with a model protein and the type of immune responses induced to the vaccine antigen. Niosomes were prepared using both the traditional thin film hydration (TFH) technique and the microfluidic mixing (MM) technique. Influenza antigen was then entrapped in the niosomes and formulations tested for their ability to induce in immune responses in immunised BALB/c mice. Niosomes prepared by MM had a mean size of 157 ± 1.8 nm and were significantly more uniform compared with the niosomes prepared using TFH (mean size 388 ± 10 nm). Niosomes play a key role as an adjuvant to help raise high antibody immune responses. This was confirmed in this study since animals treated with both types of niosomes and antigen were more responsive than unentrapped (free) antigen. Cytokine analysis showed that the TFH niosomes induced a Th1 immune response by raising IgG2a and high levels of IFN-ɣ, while the MM niosomes induced a Th2 immune response by inducing IgG1 ( < .05). These results confirmed that the method of preparation of the niosomes nanoparticles induced different immune responses and the average particle size of the niosomes differed depending on the method of manufacture. This indicates that particle size and uniformity are of importance and should be taken into consideration when designing an oral based delivery system for vaccine delivery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/08982104.2020.1768110DOI Listing
June 2021

IL-4 Mediated Resistance of BALB/c Mice to Visceral Leishmaniasis Is Independent of IL-4Rα Signaling via T Cells.

Front Immunol 2019 16;10:1957. Epub 2019 Aug 16.

Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom.

Previous studies infecting global IL-4Rα, IL-4, and IL-13mice on a BALB/c background with the visceralizing parasite have shown that the T helper 2 cytokines, IL-4, and IL-13, play influential but not completely overlapping roles in controlling primary infection. Subsequently, using macrophage/neutrophil-specific IL-4Rα deficient BALB/c mice, we demonstrated that macrophage/neutrophil unresponsiveness to IL-4 and IL-13 did not have a detrimental effect during infection. Here we expand on these findings and show that CD4 T cell-(Lck), as well as pan T cell-(iLck) specific IL-4Rα deficient mice, on a BALB/c background, unlike global IL-4Rα deficient mice, are also not adversely affected in terms of resistance to primary infection with . Our analysis suggested only a transient and tissue specific impact on disease course due to lack of IL-4Rα on T cells, limited to a reduced hepatic parasite burden at day 30 post-infection. Consequently, the protective role(s) demonstrated for IL-4 and IL-13 during infection are mediated by IL-4Rα-responsive cell(s) other than macrophages, neutrophils and T cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2019.01957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6707061PMC
October 2020

Cutaneous pharmacologic cAMP induction induces melanization of the skin and improves recovery from ultraviolet injury in melanocortin 1 receptor-intact or heterozygous skin.

Pigment Cell Melanoma Res 2020 01 24;33(1):30-40. Epub 2019 Aug 24.

The Markey Cancer Center, University of Kentucky, Lexington, KY, USA.

Homozygous loss of function of the melanocortin 1 receptor (MC1R) is associated with a pheomelanotic pigment phenotype and increased melanoma risk. MC1R heterozygosity is less well studied, although individuals inheriting one loss-of-function MC1R allele are also melanoma-prone. Using the K14-Scf C57BL/6J animal model whose skin is characterized by lifelong retention of interfollicular epidermal melanocytes like that of the human, we studied pigmentary, UV responses, and DNA repair capacity in the skin of variant Mc1r background. Topical application of forskolin, a skin-permeable pharmacologic activator of cAMP induction to mimic native Mc1r signaling, increased epidermal eumelanin levels, increased the capacity of Mc1r-heterozygous skin to resist UV-mediated inflammation, and enhanced the skin's ability to clear UV photolesions from DNA. Interestingly, topical cAMP induction also promoted melanin accumulation, UV resistance, and accelerated clearance in Mc1r fully intact skin. Together, our findings suggest that heterozygous Mc1r loss is associated with an intermediately melanized and DNA repair-proficient epidermal phenotype and that topical cAMP induction enhances UV resistance in Mc1r-heterozygous or Mc1r-wild-type individuals by increasing eumelanin deposition and by improving nucleotide excision repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pcmr.12817DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6928432PMC
January 2020

Impact of Residual Nodal Disease Burden on Technical Outcomes of Sentinel Lymph Node Biopsy for Node-Positive (cN1) Breast Cancer Patients Treated with Neoadjuvant Chemotherapy.

Ann Surg Oncol 2019 Nov 20;26(12):3846-3855. Epub 2019 Jun 20.

Breast Oncology Program, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA, USA.

Background: Recent trials have demonstrated the feasibility of sentinel lymph node biopsy (SLNB) for cN1 breast cancer patients after neoadjuvant chemotherapy (NAC). This study evaluated the technical outcomes of SLNB by residual nodal disease volume.

Methods: From a prospective database, cT1-3 cN1 patients receiving NAC and surgery from 2016 to 2017 were identified. Performance measures of post-NAC physical exam and imaging-based axillary assessment were compared. For the patients who converted to cN0 and underwent SLNB, adequate mapping (defined as ≥ 3 SLN) and the false-negative rate (FNR) of intraoperative SLN evaluation were assessed by residual nodal disease volume (ypN1-3 vs ypN0[i+]/ypN1mi vs ypN0).

Results: Of 156 cT1-3 cN1 patients, 96 converted to cN0 and underwent SLNB. Adequate mapping was achieved for 64 patients (66.7%) and was not associated with nodal volume (p = 0.12). The FNR of the intraoperative SLN evaluation was 37.8%, and smaller nodal volume was associated with FNR (p < 0.01). Of 36 patients (37.5%) who achieved an axillary pathologic complete response, 24 (66.7%) had three or more negative SLNs and were safely spared axillary lymph node dissection (ALND). The positive predictive values of physical exam versus imaging-based post-NAC nodal assessment were respectively 88% and 69.8%.

Conclusions: This study showed SLNB to be an effective tool for minimizing axillary surgery in cN1 patients treated with NAC. However, important technical limitations exist, such as inability to identify three SLNs in more than two-thirds of patients and high-false negative rates for intraoperative SLN evaluation, particularly for patients with small residual nodal volumes. Preoperative counseling should include realistic assessment of the potential need for ALND in this population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1245/s10434-019-07515-4DOI Listing
November 2019

cAMP-mediated regulation of melanocyte genomic instability: A melanoma-preventive strategy.

Adv Protein Chem Struct Biol 2019 5;115:247-295. Epub 2018 Dec 5.

The Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, United States; Department of Toxiciology and Cancer Biology, University of Kentucky College of Medicine, Lexington, KY, United States; Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY, United States. Electronic address:

Malignant melanoma of the skin is the leading cause of death from skin cancer and ranks fifth in cancer incidence among all cancers in the United States. While melanoma mortality has remained steady for the past several decades, melanoma incidence has been increasing, particularly among fair-skinned individuals. According to the American Cancer Society, nearly 10,000 people in the United States will die from melanoma this year. Individuals with dark skin complexion are protected damage generated by UV-light due to the high content of UV-blocking melanin pigment in their epidermis as well as better capacity for melanocytes to cope with UV damage. There is now ample evidence that suggests that the melanocortin 1 receptor (MC1R) is a major melanoma risk factor. Inherited loss-of-function mutations in MC1R are common in melanoma-prone persons, correlating with a less melanized skin complexion and poorer recovery from mutagenic photodamage. We and others are interested in the MC1R signaling pathway in melanocytes, its mechanisms of enhancing genomic stability and pharmacologic opportunities to reduce melanoma risk based on those insights. In this chapter, we review melanoma risk factors, the MC1R signaling pathway, and the relationship between MC1R signaling and DNA repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/bs.apcsb.2018.10.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7048968PMC
December 2019

Sirtuin 1-mediated deacetylation of XPA DNA repair protein enhances its interaction with ATR protein and promotes cAMP-induced DNA repair of UV damage.

J Biol Chem 2018 12 16;293(49):19025-19037. Epub 2018 Oct 16.

From the Markey Cancer Center and

Blunted melanocortin 1 receptor (MC1R) signaling promotes melanocyte genomic instability in part by attenuating cAMP-mediated DNA repair responses, particularly nucleotide excision repair (NER), which recognizes and clears mutagenic photodamage. cAMP-enhanced NER is mediated by interactions between the ataxia telangiectasia-mutated and Rad3-related (ATR) and xeroderma pigmentosum complementation group A (XPA) proteins. We now report a critical role for sirtuin 1 (SIRT1) in regulating ATR-mediated phosphorylation of XPA. SIRT1 deacetylates XPA at residues Lys-63, Lys-67, and Lys-215 to promote interactions with ATR. Mutant XPA containing acetylation mimetics at residues Lys-63, Lys-67, and Lys-215 exhibit blunted UV-dependent ATR-XPA interactions even in the presence of cAMP signals. ATR-mediated phosphorylation of XPA on Ser-196 enhances cAMP-mediated optimization of NER and is promoted by SIRT1-mediated deacetylation of XPA on Lys-63, Lys-67, and Lys-215. Interference with ATR-mediated XPA phosphorylation at Ser-196 by persistent acetylation of XPA at Lys-63, Lys-67, and Lys-215 delays repair of UV-induced DNA damage and attenuates cAMP-enhanced NER. Our study identifies a regulatory ATR-SIRT1-XPA axis in cAMP-mediated regulation melanocyte genomic stability, involving SIRT1-mediated deacetylation (Lys-63, Lys-67, and Lys-215) and ATR-dependent phosphorylation (Ser-196) post-translational modifications of the core NER factor XPA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA118.003940DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6295715PMC
December 2018

Multidisciplinary Management of the Axilla in Patients with cT1-T2 N0 Breast Cancer Undergoing Primary Mastectomy: Results from a Prospective Single-Institution Series.

Ann Surg Oncol 2018 Nov 4;25(12):3527-3534. Epub 2018 Jun 4.

Breast Surgical Oncology, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA, USA.

Background: The after mapping of the axilla: radiotherapy or surgery (AMAROS) trial concluded that for patients with cT1-2 N0 breast cancer and one or two positive sentinel lymph nodes (SLNs), axillary radiotherapy (AxRT) provides equivalent locoregional control and a lower incidence of lymphedema compared with axillary lymph node dissection (ALND). The study prospectively assessed how often ALND could be replaced by AxRT in a consecutive cohort of patients undergoing mastectomy for cT1-2 N0 breast cancer.

Methods: In November 2015, our multidisciplinary group agreed to omit routine intraoperative SLN evaluation for cT1-2 N0 patients undergoing upfront mastectomy and potentially eligible for postmastectomy radiation therapy (PMRT), including those 60 years of age or younger and those older than 60 years with high-risk features. Patients with one or two positive SLNs on final pathology were reviewed to determine whether PMRT including the full axilla was an appropriate alternative to ALND.

Results: From November 2015 to December 2016, 154 patients met the study criteria, and 114 (74%) formed the final study cohort. Intraoperative SLN evaluation was omitted for 76 patients (67%). Of these patients, 20 (26%) had one or two positive SLNs, and 14 of these patients received PMRT + AxRT as an alternative to ALND. Three patients returned for ALND, and three patients were observed. On univariate analysis, tumor size, LVI, number of positive lymph nodes, and receipt of chemotherapy were associated with receipt of PMRT.

Conclusions: For the majority of patients with one or two positive SLNs, ALND was avoided in favor of PMRT + AxRT. With appropriate multidisciplinary strategies, intraoperative evaluation of the SLN and immediate ALND can be avoided for patients meeting the AMAROS criteria and eligible for PMRT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1245/s10434-018-6525-3DOI Listing
November 2018

Evaluation of minor groove binders (MGBs) as novel anti-mycobacterial agents and the effect of using non-ionic surfactant vesicles as a delivery system to improve their efficacy.

J Antimicrob Chemother 2017 Dec;72(12):3334-3341

University of Cape Town, Institute of Infectious Diseases and Molecular Medicine (IDM), Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa.

Objectives: The slow development of major advances in drug discovery for the treatment of Mycobacterium tuberculosis (Mtb) infection suggests a compelling need for evaluation of more effective drug therapies against TB. New classes of drugs are constantly being evaluated for anti-mycobacterial activity with currently a very limited number of new drugs approved for TB treatment. Minor groove binders (MGBs) have previously revealed promising antimicrobial activity against various infectious agents; however, they have not yet been screened against Mtb.

Methods: The mycobactericidal activity of 96 MGB compounds against Mtb was determined using an H37Rv-GFP microplate assay. MGB hits were screened for their intracellular mycobactericidal efficacy against the clinical Beijing Mtb strain HN878 in bone-marrow-derived macrophages using standard cfu counting. Cell viability was assessed by CellTiter-Blue assays. Selected MGBs were encapsulated into non-ionic surfactant vesicles (NIVs) for drug delivery system evaluation.

Results: H37Rv-GFP screening yielded a hit-list of seven compounds at an MIC99 of between 0.39 and 1.56 μM. MGB-362 and MGB-364 displayed intracellular mycobactericidal activity against Mtb HN878 at an MIC50 of 4.09 and 4.19 μM, respectively, whilst being non-toxic. Subsequent encapsulation into NIVs demonstrated a 1.6- and 2.1-fold increased intracellular mycobacterial activity, similar to that of rifampicin when compared with MGB-alone formulation.

Conclusions: MGB anti-mycobacterial activities together with non-toxic properties indicate that MGB compounds constitute an important new class of drug/chemical entity, which holds promise in future anti-TB therapy. Furthermore, the ability of NIVs to better deliver entrapped MGB compounds to an intracellular Mtb infection suggests further preclinical evaluation is warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jac/dkx326DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5890746PMC
December 2017

The melanocortin signaling cAMP axis accelerates repair and reduces mutagenesis of platinum-induced DNA damage.

Sci Rep 2017 09 15;7(1):11708. Epub 2017 Sep 15.

The Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky, 40536, USA.

Using primary melanocytes and HEK293 cells, we found that cAMP signaling accelerates repair of bi- and mono-functional platinum-induced DNA damage. Elevating cAMP signaling either by the agonistic MC1R ligand melanocyte stimulating hormone (MSH) or by pharmacologic cAMP induction by forskolin enhanced clearance of intrastrand cisplatin-adducts in melanocytes or MC1R-transfected HEK293 cells. MC1R antagonists human beta-defensin 3 and agouti signaling protein blocked MSH- but not forskolin-mediated enhancement of platinum-induced DNA damage. cAMP-enhanced repair of cisplatin-induced DNA damage was dependent on PKA-mediated phosphorylation of ATR on S435 which promoted ATR's interaction with the key NER factor xeroderma pigmentosum A (XPA) and facilitated recruitment of an XPA-ATR-pS435 complex to sites of cisplatin DNA damage. Moreover, we developed an oligonucleotide retrieval immunoprecipitation (ORiP) assay using a novel platinated-DNA substrate to establish kinetics of ATR-pS435 and XPA's associations with cisplatin-damaged DNA. Expression of a non-phosphorylatable ATR-S435A construct or deletion of A kinase-anchoring protein 12 (AKAP12) impeded platinum adduct clearance and prevented cAMP-mediated enhancement of ATR and XPA's associations with cisplatin-damaged DNA, indicating that ATR phosphorylation at S435 is necessary for cAMP-enhanced repair of platinum-induced damage and protection against cisplatin-induced mutagenesis. These data implicate cAMP signaling as a critical regulator of genomic stability against platinum-induced mutagenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-12056-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5601928PMC
September 2017

Paracrine regulation of melanocyte genomic stability: a focus on nucleotide excision repair.

Pigment Cell Melanoma Res 2017 05 20;30(3):284-293. Epub 2017 Apr 20.

Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA.

UV radiation is a major environmental risk factor for the development of melanoma by causing DNA damage and mutations. Resistance to UV damage is largely determined by the capacity of melanocytes to respond to UV injury by repairing mutagenic photolesions. The nucleotide excision repair (NER) pathway is the major mechanism by which cells correct UV photodamage. This multistep process involves the basic steps of damage recognition, isolation, localized strand unwinding, assembly of a repair complex, excision of the damage-containing strand 3' and 5' to the photolesion, synthesis of a sequence-appropriate replacement strand, and finally ligation to restore continuity of genomic DNA. In melanocytes, the efficiency of NER is regulated by several hormonal pathways including the melanocortin and endothelin signaling pathways. Elucidating molecular mechanisms by which melanocyte DNA repair is regulated offers the possibility of developing novel melanoma-preventive strategies to reduce UV mutagenesis, especially in UV-sensitive melanoma-prone individuals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pcmr.12582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5411317PMC
May 2017

Divergence of cAMP signalling pathways mediating augmented nucleotide excision repair and pigment induction in melanocytes.

Exp Dermatol 2017 07 21;26(7):577-584. Epub 2017 Apr 21.

Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA.

Loss-of-function melanocortin 1 receptor (MC1R) polymorphisms are common in UV-sensitive fair-skinned individuals and are associated with blunted cAMP second messenger signalling and higher lifetime risk of melanoma because of diminished ability of melanocytes to cope with UV damage. cAMP signalling positions melanocytes to resist UV injury by upregulating synthesis of UV-blocking eumelanin pigment and by enhancing the repair of UV-induced DNA damage. cAMP enhances melanocyte nucleotide excision repair (NER), the genome maintenance pathway responsible for the removal of mutagenic UV photolesions, through cAMP-activated protein kinase (protein kinase A)-mediated phosphorylation of the ataxia telangiectasia-mutated and Rad3-related (ATR) protein on the S435 residue. We investigated the interdependence of cAMP-mediated melanin upregulation and cAMP-enhanced DNA repair in primary human melanocytes and a melanoma cell line. We observed that the ATR-dependent molecular pathway linking cAMP signalling to the NER pathway is independent of MITF activation. Similarly, cAMP-mediated upregulation of pigment synthesis is independent of ATR, suggesting that the key molecular events driving MC1R-mediated enhancement of genome maintenance (eg PKA-mediated phosphorylation of ATR) and MC1R-induced pigment induction (eg MITF activation) are distinct.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/exd.13291DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5507718PMC
July 2017

An evaluation of Minor Groove Binders as anti-lung cancer therapeutics.

Bioorg Med Chem Lett 2016 08 16;26(15):3478-86. Epub 2016 Jun 16.

WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, United Kingdom.

A series of 47 structurally diverse MGBs, derived from the natural product distamycin, was evaluated for anti-lung cancer activity by screening against the melanoma cancer cell line B16-F10. Five compounds have been found to possess significant activity, more so than a standard therapy, Gemcitabine. Moreover, one compound has been found to have an activity around 70-fold that of Gemcitabine and has a favourable selectivity index of greater than 125. Furthermore, initial studies have revealed this compound to be metabolically stable and thus it represents a lead for further optimisation towards a novel treatment for lung cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmcl.2016.06.040DOI Listing
August 2016

Chemical and Antimicrobial Profiling of Propolis from Different Regions within Libya.

PLoS One 2016 19;11(5):e0155355. Epub 2016 May 19.

University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, United Kingdom.

Extracts from twelve samples of propolis collected from different regions of Libya were tested for their activity against Trypanosoma brucei, Leishmania donovani, Plasmodium falciparum, Crithidia fasciculata and Mycobacterium marinum and the cytotoxicity of the extracts was tested against mammalian cells. All the extracts were active to some degree against all of the protozoa and the mycobacterium, exhibiting a range of EC50 values between 1.65 and 53.6 μg/ml. The toxicity against mammalian cell lines was only moderate; the most active extract against the protozoan species, P2, displayed an IC50 value of 53.2 μg/ml. The extracts were profiled by using liquid chromatography coupled to high resolution mass spectrometry. The data sets were extracted using m/z Mine and the accurate masses of the features extracted were searched against the Dictionary of Natural Products (DNP). A principal component analysis (PCA) model was constructed which, in combination with hierarchical cluster analysis (HCA), divided the samples into five groups. The outlying groups had different sets of dominant compounds in the extracts, which could be characterised by their elemental composition. Orthogonal partial least squares (OPLS) analysis was used to link the activity of each extract against the different micro-organisms to particular components in the extracts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0155355PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873177PMC
July 2017

The isolation of antiprotozoal compounds from Libyan propolis.

Phytother Res 2014 Dec 9;28(12):1756-60. Epub 2014 Jul 9.

Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow, G4 0NR, UK.

Propolis is increasingly being explored as a source of biologically active compounds. Until now, there has been no study of Libyan propolis. Two samples were collected in North East Libya and tested for their activity against Trypanosoma brucei. Extracts from both samples had quite high activity. One of the samples was fractionated and yielded a number of active fractions. Three of the active fractions contained single compounds, which were found to be 13-epitorulosal, acetyl-13-epi-cupressic acid and 13-epi-cupressic acid, which have been described before in Mediterranean propolis. Two of the compounds had a minimum inhibitory concentration value of 1.56 µg/mL against T. brucei. The active fractions were also tested against macrophages infected with Leishmania donovani, and again moderate to strong activity was observed with the compounds having IC50 values in the range 5.1-21.9 µg/mL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ptr.5194DOI Listing
December 2014

Infectivity of macrophages and the histopathology of cutaneous lesions, liver and spleen is attenuated by leaf extract of Vernonia amygdalina in Leishmania major infected BALB/c mice.

J Complement Integr Med 2012 Jun 18;9:Article 10. Epub 2012 Jun 18.

Department of Human Anatomy, Ahmadu Bello University.

Preliminary investigation of the in vitro and in vivo efficacies of different extracts from the leaves of Vernonia amygdalina (VA), a plant widely used in Nigeria was evaluated in Balb/C mice infected with a laboratory strain of Leishmania major (L. major). The ability of the methanol, hexane and aqueous extracts of the plant to suppress the infection rate and its cytotoxicity on macrophages and L929 cells were determined in the in vitro study. The in vivo study evaluated time course of infection, lesion progression and the histopathology of cutaneous lesions, liver and spleen after inoculation with metacyclic promastigotes. Methanolic extract of VA containing high levels of flavanoids, was the most potent extract as it showed the highest suppression on infectivity and viability of intracellular amastigotes at a concentration lower than that which elicited cytotoxicity on macrophages. Treatment of infected mice with methanolic extract of VA showed delayed onset of disease with a significant reduction in lesion size and attenuation of the histopathological outcome characterised by intact epidermis and less tissue destruction in skin, spleen and liver. In conclusion, these results demonstrate that VA has potent antileishmanial properties which warrants further investigation into the immunological mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1515/1553-3840.1617DOI Listing
June 2012

Experimental induction of paromomycin resistance in antimony-resistant strains of L. donovani: outcome dependent on in vitro selection protocol.

PLoS Negl Trop Dis 2012 29;6(5):e1664. Epub 2012 May 29.

Laboratory of Microbiology, Parasitology and Hygiene, University of Antwerp, Antwerp, Belgium.

Paromomycin (PMM) has recently been introduced for treatment of visceral leishmaniasis in India. Although no clinical resistance has yet been reported, proactive vigilance should be warranted. The present in vitro study compared the outcome and stability of experimental PMM-resistance induction on promastigotes and intracellular amastigotes. Cloned antimony-resistant L. donovani field isolates from India and Nepal were exposed to stepwise increasing concentrations of PMM (up to 500 µM), either as promastigotes or intracellular amastigotes. One resulting resistant strain was cloned and checked for stability of resistance by drug-free in vitro passage as promastigotes for 20 weeks or a single in vivo passage in the golden hamster. Resistance selection in promastigotes took about 25 weeks to reach the maximal 97 µM inclusion level that did not affect normal growth. Comparison of the IC(50) values between the parent and the selected strains revealed a 9 to 11-fold resistance for the Indian and 3 to 5-fold for the Nepalese strains whereby the resistant phenotype was also maintained at the level of the amastigote. Applying PMM pressure to intracellular amastigotes produced resistance after just two selection cycles (IC(50) = 199 µM) compared to the parent strain (IC(50) = 45 µM). In the amastigote-induced strains/clones, lower PMM susceptibilities were seen only in amastigotes and not at all in promastigotes. This resistance phenotype remained stable after serial in vitro passage as promastigote for 20 weeks and after a single in vivo passage in the hamster. This study clearly demonstrates that a different PMM-resistance phenotype is obtained whether drug selection is applied to promastigotes or intracellular amastigotes. These findings may have important relevance to resistance mechanism investigations and the likelihood of resistance development and detection in the field.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0001664DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3362622PMC
August 2012

Peroral amphotericin B polymer nanoparticles lead to comparable or superior in vivo antifungal activity to that of intravenous Ambisome® or Fungizone™.

PLoS One 2011 6;6(10):e25744. Epub 2011 Oct 6.

Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom.

Background: Despite advances in the treatment, the morbidity and mortality rate associated with invasive aspergillosis remains unacceptably high (70-90%) in immunocompromised patients. Amphotericin B (AMB), a polyene antibiotic with broad spectrum antifungal activity appears to be a choice of treatment but is available only as an intravenous formulation; development of an oral formulation would be beneficial as well as economical.

Methodology: Poly(lactide-co-glycolode) (PLGA) nanoparticles encapsulating AMB (AMB-NPs) were developed for oral administration. The AMB-NPs were 113 ± 20 nm in size with ~70% entrapment efficiency at 30% AMB w/w of polymer. The in vivo therapeutic efficacy of oral AMB-NPs was evaluated in neutropenic murine models of disseminated and invasive pulmonary aspergillosis. AMB-NPs exhibited comparable or superior efficacy to that of Ambisome® or Fungizone™ administered parenterally indicating potential of NPs as carrier for oral delivery.

Conclusions: The present investigation describes an efficient way of producing AMB-NPs with higher AMB pay-load and entrapment efficiency employing DMSO as solvent and ethanol as non-solvent. The developed oral formulation was highly efficacious in murine models of disseminated aspergillosis as well as an invasive pulmonary aspergillosis, which is refractory to treatment with IP Fungizone™ and responds only modestly to AmBisome®.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0025744PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3188565PMC
February 2012

Endogenous IL-13 plays a crucial role in liver granuloma maturation during Leishmania donovani infection, independent of IL-4Rα-responsive macrophages and neutrophils.

J Infect Dis 2011 Jul;204(1):36-43

Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.

Previous studies comparing interleukin 4 receptor α (IL-4Rα)(-/-) and interleukin 4 (IL-4)(-/-) BALB/c mice have indicated that interleukin 13 (IL-13), whose receptor shares the IL-4Rα subunit with IL-4, plays a protective role during visceral leishmaniasis. We demonstrate that IL-13(-/-) BALB/c mice were less able to control hepatic growth of Leishmania donovani compared with wild-type mice. This correlated with significantly retarded granuloma maturation in IL-13(-/-) mice, defective interferon γ (IFN-γ) production, and elevated IL-4 and interleukin 10 (IL-10) levels. L. donovani-infected IL-13(-/-) mice also responded poorly to sodium stibogluconate-mediated chemotherapy compared with wild-type BALB/c mice. Because murine lymphocytes do not have IL-13 receptors, we examined the ability of macrophage/neutrophil-specific IL-4Rα(-/-) mice to control primary infection with L. donovani and to respond to chemotherapy. Macrophage/neutrophil-specific IL-4Rα(-/-) mice were as resistant to leishmaniasis as wild-type mice, and chemotherapy retained its efficacy. Consequently, in L. donovani infected BALB/c mice, IL-13 promotes hepatic granuloma formation and controls parasite burdens independently of direct effects on macrophages/neutrophils.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/infdis/jir080DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3105032PMC
July 2011

Lipid vesicle size of an oral influenza vaccine delivery vehicle influences the Th1/Th2 bias in the immune response and protection against infection.

Vaccine 2009 Jun 5;27(27):3643-9. Epub 2009 Apr 5.

Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, Scotland, UK.

Previous studies, using parenteral administration of antigen in lipid vesicles, have indicated a possible role for vesicle size in determining the Th1/Th2 bias of the resulting immune response. We have also demonstrated that the incorporation of bile salts into lipid vesicles (bilosomes) allows successful induction of mucosal and systemic immunity via the oral route. The following study was therefore carried out to determine whether size could also influence the Th1/Th2 bias in the immune response to bilosome entrapped influenza A antigen containing haemagglutinin administered by the oral route in the mouse and whether this could influence the disease process in the classical ferret model of disease. Consequently we produced two formulations of influenza A antigen entrapped in bilosomes: BV3 which contained a single population (range 10-100 nm, Z-average diameter 250 nm) and BV which had two populations (60-350 and 400-2,500 nm, Z-average 980 nm). Following oral vaccination of BALB/c mice, BV was found to generate an immune response that had a significantly greater Th1 bias than BV3 as measured by serum IgG2a production and antigen-induced spleen cell IFN-gamma production. In the traditional infection challenge model (ferrets) vaccination with BV (large) vesicles resulted in greater protection in terms of symptom-score and a higher responder number. However, both oral vaccine formulations were an improvement on intramuscular administration in terms of higher antibody production, lower temperatures, and reduced symptoms over time, post-infection. The results presented here demonstrate that oral vaccine formulations can be physically modified to manipulate resultant immune responses following vaccination and consequently can be designed to enhance the effectiveness of candidate vaccine antigens.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vaccine.2009.03.040DOI Listing
June 2009

Toll-like receptor-4-mediated macrophage activation is differentially regulated by progesterone via the glucocorticoid and progesterone receptors.

Immunology 2008 Sep 28;125(1):59-69. Epub 2008 Mar 28.

Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.

Macrophage function has been demonstrated to be subject to modulation by progesterone. However, as this steroid hormone can act through the glucocorticoid receptor as well as the progesterone receptor, the mechanism of action has not been precisely characterized. To determine the mode of action, we compared the ability of progesterone, norgestrel (a synthetic progesterone-receptor-specific agonist) and dexamethasone (a synthetic glucocorticoid receptor agonist) to modulate macrophage function following stimulation of the Toll-like receptor-4 (TLR-4) ligand lipopolysaccharide (LPS). The results demonstrate that following stimulation of TLR-4 with LPS and cotreatment with either progesterone or dexamethasone, but not norgestrel, there is a significant reduction in nitric oxide (NO) production, indicating that this progesterone-mediated effect is through ligation of the glucocorticoid receptor. In contrast, LPS-induced interleukin-12 (IL-12) production could be downregulated by all three steroids, indicating that ligation by progesterone of either the glucocorticoid or the progesterone receptors or both could mediate this effect. While progesterone downmodulated NO-mediated killing of Leishmania donovani by activated macrophages in vitro, most probably via the glucocorticoid receptor, it had little effect on Toxoplasma gondii growth in these cells. This would suggest that progesterone-mediated increased susceptibility to T. gondii during pregnancy is more likely to be related to the ability of the hormone to downregulate IL-12 production and a type-1 response utilizing the progesterone as well as the glucocorticoid receptors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1365-2567.2008.02820.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2526260PMC
September 2008

Carbohydrate-based micelle clusters which enhance hydrophobic drug bioavailability by up to 1 order of magnitude.

Biomacromolecules 2006 Dec;7(12):3452-9

Department of Pharmaceutical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, U.K.

Amphiphilic chitosan-based polymers (Mw < 20 kDa) self-assemble in aqueous media at low micromolar concentrations to give previously unknown micellar clusters of 100-300 nm in size. Micellar clusters comprise smaller 10-30 nm aggregates, and the nanopolarity/drug incorporation efficiency of their hydrophobic domains can be tailored by varying the degree of lipidic derivatization and molecular weight of the carbohydrate. The extent of drug incorporation by these novel micellar clusters is 1 order of magnitude higher than is seen with triblock copolymers, with molar polymer/drug ratios of 1:48 to 1:67. On intravenous injection, the pharmacodynamic activity of a carbohydrate propofol formulation is increased by 1 order of magnitude when compared to a commercial emulsion formulation, and on topical ocular application of a carbohydrate prednisolone formulation, initial drug aqueous humor levels are similar to those found with a 10-fold dose of prednisolone suspension.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/bm0604000DOI Listing
December 2006

Identification of the benzodiazepines as a new class of antileishmanial agent.

Bioorg Med Chem Lett 2007 Feb 6;17(3):624-7. Epub 2006 Nov 6.

Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, UK.

The continual increase in drug resistance; the lack of new chemotherapeutic agents; the toxicity of existing agents and the increasing morbidity with HIV co-infection mean the search for new antileishmanial agents has never been more urgent. We have identified the benzodiazepines as a structural class for antileishmanial hit optimisation, and demonstrated that their in vitro activity is comparable with the clinically used drug, sodium stibogluconate, and that the compounds are not toxic to macrophages.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmcl.2006.11.004DOI Listing
February 2007

Endogenous interleukin-18 is involved in immunity to Leishmania donovani but its absence does not adversely influence the therapeutic activity of sodium stibogluconate.

Immunology 2006 Nov 26;119(3):348-54. Epub 2006 Jul 26.

Department of Pharmaceutical Sciences, University of Strathclyde, Glasgow, UK.

Immunity to Leishmania donovani is associated with an interleukin (IL)-12 driven T helper 1 (Th1) response. In addition, the ability to respond to chemotherapy with sodium stibogluconate (SSG) requires a fully competent immune response and both Th1 and Th2 responses have been shown to positively influence the outcome of drug treatment. In the present study, the influence of IL-18, which can modulate both interferon (IFN)-gamma and IL-4 production, on the outcome of primary L. donovani infection and SSG therapy following infection was assessed using BALB/c IL-18-deficient and wild type mice. IL-18 deficiency was associated with an increased susceptibility to L. donovani infection, evident by day 40 post infection, resulting in higher parasite burdens in the spleen, liver, and bone marrow compared with wild type control animals. Infected IL-18-deficient mice had significantly lower splenocyte concanavalin A (ConA) induced IFN-gamma production as well as lower serum IL-12 and IFN-gamma levels, indicating a reduced Th1 response. However, drug treatment was equally effective in both mouse strains and restored serum IL-12 and IFN-gamma levels, and IFN-gamma production by ConA stimulated splenocytes of IL-18-deficient mice, to levels equivalent to similarly treated wild type mice.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1365-2567.2006.02438.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1819581PMC
November 2006

Oral delivery of tetanus toxoid using vesicles containing bile salts (bilosomes) induces significant systemic and mucosal immunity.

Methods 2006 Feb;38(2):90-5

Department of Immunology, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, University of Strathclyde, Glasgow G4 0NR, UK.

Protein antigens administered via the oral route are exposed to a hostile environment in the gastrointestinal tract, consisting of digestive enzymes and a range of pH (1-7.5). Using a delivery system can afford protection to entrapped components against degradation and permit delivery of antigen to the cells responsible for generating local and systemic immune responses. In this comparative study, mice were immunised orally with tetanus toxoid (40 or 200 microg dose/mouse, four doses in total) entrapped in non-ionic surfactant vesicles formulated with bile salts (bilosomes). The higher entrapped dose (BV-TT, 200 microg) induced IgG1 by study week 3 to similar levels to those observed with subcutaneous un-entrapped TT at the lower (<50 microg) dose. However, both bilosome formulations (BV-TT, low, and high doses), though not un-entrapped TT, caused a rise in the numbers of IgA positive plasma cells observed in the small intestine, primarily in the first 15 cm of the small intestine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ymeth.2005.11.002DOI Listing
February 2006
-->