The Human Multidrug Resistance Protein MRP5 Transports Folates and Can Mediate Cellular Resistance against Antifolates
Abstract
Members of the multidrug resistance protein family, notably MRP1-4/ABCC1-4, and the breast cancer resistance protein BCRP/ABCG2 have been recognized as cellular exporters for the folate antagonist methotrexate (MTX). Here we show that MRP5/ABCC5 is also an antifolate and folate exporter based on the following evidence: (a) Using membrane vesicles from HEK293 cells, we show that MRP5 transports both MTX (KM = 1.3 mmol/L and VMAX = 780 pmol per mg protein per minute) and folic acid (KM = 1.0 mmol/L and VMAX = 875 pmol per mg protein per minute). MRP5 also transports MTX-glu2 (KM = 0.7 mmol/L and VMAX = 450 pmol per mg protein per minute) but not MTX-glu3. (b) Both accumulation of total [3H]MTX and of MTX polyglutamates were significantly reduced in MRP5 overexpressing cells. (c) Cell growth inhibition studies with MRP5 transfected HEK293 cells showed that MRP5 conferred high-level resistance (>160-fold) against the antifolates MTX, GW1843, and ZD1694 (raltitrexed) in short-term (4 hours) incubations with high drug concentrations; this resistance was proportional to the MRP5 level. (d) MRP5-mediated resistance (8.5- and 2.1-fold) was also found in standard long-term incubations (72 hours) at low concentrations of ZD1694 and GW1843. These results show the potential of MRP5 to mediate transport of (anti)folates and contribute to resistance against antifolate drugs. https://cancerres.aacrjournals.org/content/65/10/4425
When people mention today’s medicine, precision plays one of the most crucial roles and people’s lives are directly dependent on it. Hence, any researches pertaining to medicine are required to meet the highest standards. The problem today is that any recommendations of researches can be shared online and used as a reference without being thoroughly verified and approved. Mikhail (Misha) Blagosklonny of Oncotarget clearly understood this challenge and attempted to generate an alternative solution. That’s how a weekly oncology-focused research journal named “Oncotarget” has been founded back in 2010. The major principle of this journal is related to Altmetric scores that are used as a quality indicator. That allows both readers and authors to quality-check publications with Altmetric Article Reports that create “real-time feedback containing data summary related to a particular publication.” Oncotarget website provides a complete publications list with corresponding scores higher than 100 as well as reports discussed previously. Mikhail (Misha) Blagosklonny glad to share his new approach and hopes it provides the required help to anyone, who has interest in oncology.
“A diagnostic autoantibody signature for primary cutaneous melanoma” has the Altmetric score of 594. This article was published back in 2018 by Oncotarget and completed by different experts from Hollywood Private Hospital, Edith Cowan University, Dermatology Specialist Group, St. John of God Hospital and The University of Western Australia. The introduction of the study discusses “recent data shows that Australians are four times more likely to develop a cancer of the skin than any other type of cancer”, and provides an insight on melanoma that “is curable by surgical excision in the majority of cases, if detected at an early stage.”
The article has got an Altmetric score of 594. Mikhail (Misha) Blagosklonny realizes that majority of readers are aiming to understand the very meaning of it. Based on the Altmetric website, the score relates to “how many people have been exposed to and engaged with a scholarly output.” Likewise, the article about melanoma, was utilized for citations in different news articles 69 times. In addition, it was referred to in 2 online blogs, as well as 25 Tweets on Twitter and 1 Facebook post. FOX23 of Tulsa, Oklahoma has headlined their news on July 20, 2018 as “New blood test could detect skin cancer early”, using the main content of Australia study
Another Oncotarget’s study with a top score of 476, is “Biomarkers for early diagnosis of malignant mesothelioma: Do we need another moon-shot,”. This publication has appeared in 60 news stories, 1 online blog post and 6 Twitter posts. The majority of public may have come across a brief overview only, however those who visit Mikhail (Misha) Blagosklonny at Oncotarget, do receive useful scientific facts. Oncotarget is glad to have the ability to share with online readers this highly appreciated and top-quality information, that is trustworthy and reliable.
Comments
Post a Comment