Expression of Breast Cancer Resistance Protein (BCRP/ABCG2) in tumor cells is associated with resistance to multiple chemotherapeutic agents. BCRP also protects against phototoxicity by mediating the efflux of protoporphyrins from cells. However, chemotherapy and photodynamic therapy are effective treatment options for cancer. Furthermore, protoporphyrins are essential, in the form of heme, for the synthesis of nitric oxide, over-production of which is associated with cancer. This raises the question as to whether the expression of this transporter is altered in cancer. To address this question, we investigated the expression of BCRP in colorectal cancer and cervical cancer. Paired normal and cancer tissues from colectomy specimens were used for the analysis of BCRP mRNA by RT-PCR and Northern blot. BCRP was analyzed by immunohistochemistry/immunofluorescence. Similar studies were also done with specimens of normal cervix and cancer cervix. A commercial dot blot was probed to quantify the expression of BCRP in paired normal and cancer cDNA samples from 154 patients with tumors in 19 different tissues. BCRP mRNA was present in normal colorectal tissue and showed a 6-fold decrease in cancer. BCRP was abundant in the normal colon and showed a decrease in colon cancer. The down-regulation of BCRP mRNA and protein was also evident in cervical cancer. There was also a decrease in BCRP mRNA in cancer in 12 of the 19 different tissues collected from 154 patients. These data show that cancer-associated down-regulation of BCRP is likely to be a common phenomenon in several tissues. Decreased expression of BCRP may have a role in tumorigenesis by allowing accumulation of genotoxins and over-production of nitric oxide.
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http://dx.doi.org/10.1016/j.bbrc.2006.02.172 | DOI Listing |
J Ethnopharmacol
January 2025
National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, MS, 38677, United States; Department of Bio-Molecular Sciences, School of Pharmacy, The University of Mississippi, MS, 38677, United States. Electronic address:
Ethnopharmacological Relevance: Phyllanthus amarus is ethnomedicinally used to treat gallbladder stones, kidney stones and chronic liver diseases. P. amarus is gaining popularity as an ingredient in many botanical dietary supplements.
View Article and Find Full Text PDFBiol Pharm Bull
November 2024
Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama.
The blood-brain barrier (BBB) is a dynamic interface controlling the compound translocation between the blood and the brain, thereby maintaining neural homeostasis. There is cumulative evidence that BBB impairment during diabetes mellitus (DM) takes part in the progression of cognitive dementia. As tight junction proteins and ATP-binding cassette (ABC) transporters regulate substance exchange between the circulating blood and brain, the expression and function of these molecules under DM should be fully clarified.
View Article and Find Full Text PDFArch Pharm Res
November 2024
Institute of Pharmacology, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan.
Human antigen R (HuR), an RNA-binding protein, is implicated in regulating mRNA stability and translation in cancer, especially in triple-negative breast cancer (TNBC), a highly aggressive form. CRISPR/Cas9-mediated HuR knockout (HuR CRISPR) presents a promising genetic therapeutic approach, but it encounters transfection limitations. Docetaxel (DTX), an effective cytotoxic agent against metastatic breast cancer (BC), faces challenges related to vehicle-associated adverse events in DTX formulations.
View Article and Find Full Text PDFMol Immunol
November 2024
Department of Pharmacy, People's Hospital of Peking University, Beijing, China. Electronic address:
CPT Pharmacometrics Syst Pharmacol
November 2024
Division of Pharmacy and Optometry, Centre for Applied Pharmacokinetic Research, School of Health Sciences, University of Manchester, Manchester, UK.
Breastfeeding is the most complete nutritional method of feeding infants, but several impediments affect the decision to breastfeed, including questions of drug safety for medications needed during lactation. Despite recent FDA guidance, few labels provide clear dosing advice during lactation. Physiologically based pharmacokinetic modeling (PBPK) is well suited to mechanistically explore pharmacokinetics and dosing paradigms to fill gaps in the absence of extensive clinical studies and complement existing real-world data.
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