Pharmaceutical Sciences Publications (UMKC)
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Items in this collection are the scholarly output of the Division of Pharmaceutical Sciences faculty, staff, and students, either alone or as co-authors, and which may or may not have been published in an alternate format.
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Item Computational analysis and predictive modeling of polymorph descriptors(2013-02-04) Lee, Yugyung, 1960-; Jana, Sourav; Acharya, Gayathri; Lee, Chi H. (Chi-Hyun)Abstract Background A computation approach based on integrating high throughput binding affinity comparison and binding descriptor classifications was utilized to establish the correlation among substrate properties and their affinity to Breast Cancer Resistant Protein (BCRP). The uptake rates of Mitoxantrone in the presence of various substrates were evaluated as an in vitro screening index for comparison of their binding affinity to BCRP. The effects of chemical properties of various chemotherapeutics, such as antiviral, antibiotic, calcium channel blockers, anticancer and antifungal agents, on their affinity to BCRP, were evaluated using HEK (human embryonic kidney) cells in which 3 polymorphs, namely 482R (wild type) and two mutants (482G and 482T) of BCRP, have been identified. The quantitative structure activity relationship (QSAR) model was developed using the sequential approaches of Austin Model 1 (AM1), CODESSA program, heuristic method (HM) and multiple linear regression (MLR) to establish the relationship between structural specificity of BCRP substrates and their uptake rates by BCRP polymorphs. Results The BCRP mutations may induce conformational changes as manifested by the altered uptake rates of Mitoxantrone by BCRP in the presence of other competitive binding substrates that have a varying degree of affinities toward BCRP efflux. This study also revealed that the binding affinity of test substrates to each polymorph was affected by varying descriptors, such as constitutional, topological, geometrical, electrostatic, thermodynamic, and quantum chemical descriptors. Conclusion Descriptors involved with the net surface charge and energy level of substrates seem to be the common integral factors for defining binding specificity of selected substrates to BCRP polymorph. The reproducible outcomes and validation process further supported the accuracy of the computational model in assessing the correlation among descriptors involved with substrate affinity to BCRP polymorph. A quantitative computation approach will provide important structural insight into optimal designing of new chemotherapeutic agents with improved pharmacological efficacies.Item Silencing of the IKKepsilon gene by siRNA inhibits invasiveness and growth of breast cancer cells(2010-09-23) Qin, Bin; Cheng, KunAbstract Introduction IκB kinase ε (IKKε) is a member of the IKK family that plays an important role in the activation of NF-κB. Overexpressed in more than 30% of breast cancers, IKKε has been recently identified as a potential breast cancer oncogene. The purpose of the present study is to examine the therapeutic potential of IKKε siRNA on human breast cancer cells. Methods Eight siRNAs targeting different regions of the IKKε mRNA were designed, and the silencing effect was screened by quantitative real-time RT-PCR. The biological effects of synthetic siRNAs on human breast cancer cells were investigated by examining the cell proliferation, migration, invasion, focus formation, anchorage-independent growth (via soft agar assay), cell cycle arrest, apoptosis (via annexing binding), NF-κB basal level, and NF-κB-related gene expressions upon the IKKε silencing. Results Silencing of IKKε in human breast cancer cells resulted in a decrease of focus formation potential and clonogenicity as well as in vitro cell migration/invasion capabilities. Moreover, knockdown of IKKε suppressed cell proliferation. Cell cycle assay showed that the anti-proliferation effect of IKKε siRNA was mediated by arresting cells in the G0/G1 phase, which was caused by downregulation of cyclin D1. Furthermore, we demonstrated that silencing of IKKε inhibited the NF-κB basal activity as well as the Bcl-2 expression. Significant apoptosis was not observed in breast cancer cells upon the silencing of IKKε. The present study provided the first evidence that silencing IKKε using synthetic siRNA can inhibit the invasiveness properties and proliferation of breast cancer cells. Conclusions Our results suggested that silencing IKKε using synthetic siRNA may offer a novel therapeutic strategy for breast cancer.Item Encapsulation of docetaxel in oily core polyester nanocapsule intended for breast cancer therapy(2011-12-14) Youm, Ibrahima; Yang, Xiao Y; Murowchick, James B; Youan, Bi-Botti CAbstract This study is designed to test the hypothesis that docetaxel [Doc] containing oily core nanocapsules [NCs] could be successfully prepared with a high percentage encapsulation efficiency [EE%] and high drug loading. The oily core NCs were generated according to the emulsion solvent diffusion method using neutral Labrafac CC and poly(d, l-lactide) [PLA] as oily core and shell, respectively. The engineered NCs were characterized for particle mean diameter, zeta potential, EE%, drug release kinetics, morphology, crystallinity, and cytotoxicity on the SUM 225 breast cancer cell line by dynamic light scattering, high performance liquid chromatography, electron microscopies, powder X-ray diffraction, and lactate dehydrogenase bioassay. Typically, the formation of Doc-loaded, oily core, polyester-based NCs was evidenced by spherical nanometric particles (115 to 582 nm) with a low polydispersity index (< 0.05), high EE% (65% to 93%), high drug loading (up to 68.3%), and a smooth surface. Powder X-ray diffraction analysis revealed that Doc was not present in a crystalline state because it was dissolved within the NCs' oily core and the PLA shell. The drug/polymer interaction has been indeed thermodynamically explained using the Flory-Huggins interaction parameters. Doc release kinetic data over 144 h fitted very well with the Higuchi model (R 2 > 0.93), indicating that drug release occurred mainly by controlled diffusion. At the highest drug concentration (5 μM), the Doc-loaded oily core NCs (as a reservoir nanosystem) enhanced the native drug cytotoxicity. These data suggest that the oily core NCs are promising templates for controlled delivery of poorly water soluble chemotherapeutic agents, such as Doc.Item Both P-gp and MRP2 mediate transport of Lopinavir, a protease inhibitor(Interdisciplinary Doctoral Student Council at the University of Missouri- Kansas City, 2007) Agarwal, Sheetal; Pal, Dhananjay; Mitra, Ashim K.Polarized epithelial non-human (canine) cell lines stably transfected with human or murine complementary DNA (cDNA) encoding for various efflux transporters (P-gp/MDR1, MRP1, MRP2, and Bcrp1) were used to study transepithelial transport of Lopinavir (LVR) and compare results with the MDCKII-Wild type cells. These transmembrane proteins cause multidrug resistance by decreasing the total intracellular accumulation of drugs. Lopinavir efflux was directional and was completely inhibited by MK-571, a selective MRP family inhibitor in the MDCKII-MRP2 cell line. Similarly, LVR efflux was also inhibited by P-gp inhibitors P-gp 4008 and GF120918 in the MDCKII-MDR1 cell line. The efflux ratios (Efflux rate/ Influx rate) of LVR in the absence of any efflux inhibitors in the MDCK-Wild type, MDCKII-MDR1, MDCKII-MRP1, MDCKII-MRP2 and MDCKII-Bcrp1 cell monolayers were 1.32, 4.91, 1.26 and 2.89 respectively. The MDCKII-MDR1 and MDCKII-MRP2 cells have significantly increased LVR efflux ratio relative to the parental cells due to the apically directed transport by MDR1 and MRP2 respectively. The efflux ratios in MRP2 and MDR1 transfected cell lines were close to unity in the presence of MK-571 and P-gp 4008 respectively; indicating that LVR efflux by MRP2 and P-gp was completely inhibited by their selective inhibitors. MDCKII-MRP1 cells did not exhibit a significant reduction in the LVR efflux relative to the parental cells, indicating that LVR is not a good substrate for MRP1. Transport studies across MDCKII-Bcrp1 cells indicated that LVR is not transported by Bcrp1 and is not a substrate for this efflux protein. In conclusion, this study presents direct evidence that LVR is effluxed by both P-gp and MRP2 which may contribute to its poor oral bioavailability and limited penetration into the CNS.