P-Glycoprotein

Publication Title: 
Medicinal Chemistry (Shariqah (United Arab Emirates))

Non-steroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) specific inhibitors are anti-inflammatory agents that have also shown to be useful in anticancer therapy. The effects of chebulagic acid (CA), a benzopyran tannin from Terminalia chebula having COX-2/5-LOX dual inhibitory properties, on the sensitivity of doxorubicin (Dox) in human hepatocellular carcinoma cell line HepG2 were studied in the present investigation. CA increased the accumulation of Dox in a concentration dependant manner and also enhanced the cytotoxicity of Dox in HepG2 cells by 20 folds.

Author(s): 
Achari, Chandrani
Reddy, Gorla V.
Reddy, T. C. M.
Reddanna, Pallu
Publication Title: 
Biological & Pharmaceutical Bulletin

Candida albicans is one of the most prevalent human opportunistic pathogens. C. albicans undergoes a yeast-to-hyphal transition that has been identified as a virulence factor as well as a critical element for mature biofilm formation. A previous study in our lab showed retigeric acid B (RAB), a lichen derived pentacyclic triterpenoid, displayed synergistic antifungal activity with azoles. We now showed that this combination also proved to be adequate in combating the formation of hyphae in vitro.

Author(s): 
Chang, Wenqiang
Li, Ying
Zhang, Li
Cheng, Aixia
Liu, Yongqing
Lou, Hongxiang
Publication Title: 
Drug Metabolism and Disposition: The Biological Fate of Chemicals

The objective of this study was to investigate whether the decrease in artemisinin bioavailability after repeated oral dosing in humans can be a result of increased efflux of artemisinin by P-glycoprotein or decreased membrane transport at the intestinal barrier. The effective jejunal permeability (Peff) of artemisinin was investigated using an in situ rat perfusion model. Fifty-four rats were randomized to one of three treatment arms: no pretreatment, pretreatment with artemisinin emulsion for 5 days (60 mg/kg/day, p.o. ), or pretreatment with emulsion vehicle for 5 days.

Author(s): 
Svensson, U. S.
Sandström, R.
Carlborg, O.
Lennernäs, H.
Ashton, M.
Publication Title: 
Biological & Pharmaceutical Bulletin

Overcoming MDR (multidrug resistance) phenomena is a crucial aspect of cancer chemotherapy research. Artemisinin and its derivatives have been found to inhibit the proliferation of cancer cells in the microM range. They poorly inhibited the function of P-glycoprotein and did not inhibit the function of MRP1-protein. The concentrations required to inhibit by 50% the function of P-glycoprotein are 110+/-5 microM.

Author(s): 
Reungpatthanaphong, Paiboon
Mankhetkorn, Samlee
Publication Title: 
Antimicrobial Agents and Chemotherapy

Resistance to antimalarial drugs is a public health problem worldwide. Molecular markers for drug-resistant malaria, such as pfcrt and pfmdr1 polymorphisms, could serve as useful surveillance tools. To evaluate this possibility, sequence polymorphisms in pfcrt (position 76) and pfmdr1 (positions 86, 184, 1034, 1042, and 1246) and in vitro drug sensitivities were measured for 65 Plasmodium falciparum isolates from Thailand, Myanmar, Vietnam, and Bangladesh.

Author(s): 
Pickard, Amy L.
Wongsrichanalai, Chansuda
Purfield, Anne
Kamwendo, Deborah
Emery, Kathryn
Zalewski, Christy
Kawamoto, Fumihiko
Miller, R. Scott
Meshnick, Steven R.
Publication Title: 
Molecular Pharmacology

Artemisinin drugs are of utmost importance in the treatment of malaria, because they represent the sole class of therapeutically used antimalarial drugs to which malaria parasites have not yet developed resistance. The major disadvantage of these medicines is the comparatively high recrudescence rate, which has been attributed to the remarkable decrease of artemisinin plasma concentrations during multiple dosing. Autoinduction of CYP2B6-mediated metabolism has been implicated as the underlying mechanism. So far, the molecular mechanism of induction by artemisinin has not been resolved.

Author(s): 
Burk, Oliver
Arnold, Katja A.
Nüssler, Andreas K.
Schaeffeler, Elke
Efimova, Ekaterina
Avery, Bonnie A.
Avery, Mitchell A.
Fromm, Martin F.
Eichelbaum, Michel
Publication Title: 
Antimicrobial Agents and Chemotherapy

The artemisinin-based combination therapies artemether-lumefantrine (AL) and amodiaquine (AQ) plus artesunate have been adopted for treatment of Plasmodium falciparum malaria in many African countries. Molecular markers of parasite resistance suitable for surveillance have not been established for any of the component drugs in either of these combinations. We assessed P. falciparum mdr1 (Pfmdr1) alleles present in 300 Tanzanian children presenting with uncomplicated falciparum malaria, who were enrolled in a clinical trial of antimalarial therapy.

Author(s): 
Humphreys, G. S.
Merinopoulos, I.
Ahmed, J.
Whitty, C. J. M.
Mutabingwa, T. K.
Sutherland, C. J.
Hallett, R. L.
Publication Title: 
British Journal of Pharmacology

BACKGROUND AND PURPOSE: Artemisinin is an antimalarial drug exerting pleiotropic effects, such as the inhibition of the transcription factor nuclear factor-kappa B and of the sarcoplasmic/endoplasmic reticulum Ca(++)-ATPase (SERCA) of P. falciparum.

Author(s): 
Riganti, C.
Doublier, S.
Viarisio, D.
Miraglia, E.
Pescarmona, G.
Ghigo, D.
Bosia, A.
Publication Title: 
The Journal of Infectious Diseases

Plasmodium falciparum response mechanisms to the major artemisinin-based combination therapies (ACTs) are largely unknown. Multidrug-resistance protein (MRP)-like adenosine triphosphate (ATP)-binding cassette transporters are known to be related to multidrug resistance in many organisms. Therefore, we hypothesized that sequence variation in pfmrp1 can contribute to decreased parasite sensitivity to ACT. Through sequencing of the pfmrp1 open reading frame for 103 geographically diverse P.

Author(s): 
Dahlstrom, Sabina
Ferreira, Pedro E.
Veiga, M. Isabel
Sedighi, Nazli
Wiklund, Lisa
Mårtensson, Andreas
Färnert, Anna
Sisowath, Christin
Osorio, Lyda
Darban, Hamid
Andersson, Björn
Kaneko, Akira
Conseil, Gwenaëlle
Björkman, Anders
Gil, J. Pedro
Publication Title: 
Asian Pacific journal of cancer prevention: APJCP

Cytotoxic activity of artemisinin and derivatives in the presence and absence of holo-transferrin and expression of genes involved in resistance of cancer cells were investigated in human cholangiocarcinoma (CL-6) and hepatocarcinoma (Hep-G2) cell lines in vitro. After incubation with the test drugs and 5-fluorouracil (5-FU) cytotoxicity was asessed by MTT assay.

Author(s): 
Chaijaroenkul, Wanna
Viyanant, Vithoon
Mahavorasirikul, Wiratchanee
Na-Bangchang, Kesara

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