Multidrug Resistance-Associated Protein 2 Expression Is Upregulated by Adenosine 5’-Triphosphate in Colorectal Cancer Cells and Enhances Their Survival to Chemotherapeutic Drugs

Abstract

Extracellular adenosine 5’-triphosphate (ATP) is a signaling molecule that induces a plethora of effects ranging from the regulation of cell proliferation to modulation of cancerous cell behavior. In colorectal cancer, ATP was reported to stimulate epithelial cell proliferation and possibly promote resistance to anti-cancer treatments. However, the exact role of this danger-signaling molecule on cancerous intestinal epithelial cells (IECs) in response to chemotherapeutic agents remains unknown. To address how ATP may influence the response of cancerous IECs to chemotherapeutic agents, we used Caco-2 cells, which display enterocyte-like features, to determine the effect of ATP on the expression of multidrug resistance-associated protein 2 (MRP2). Gene and protein expression were determined by quantitative real-time PCR (qRT-PCR) and Western blotting. Resistance to etoposide, cisplatin and doxorubicin was determined by MTT assays in response to ATP stimulation of Caco-2 cells and in cells for which MRP2 expression was down-regulated by shRNA. ATP increased the expression of MRP2 at both the mRNA and protein levels. MRP2 expression involved an ATP-dependent stimulation of the MEK/ERK signaling pathway that was associated with an increase in relative resistance of Caco-2 cells to etoposide. Abolition of MRP2 expression using shRNA significantly reduced the protective effect of MRP2 toward etoposide as well as to cisplatin and doxorubicin. This study describes the mechanism by which ATP may contribute to the chemoresistance of cancerous IECs in colorectal cancer. Given the heterogeneity of colorectal adenocarcinoma responses to anti-cancer drugs, these findings call for further study to understand the role of P2 receptors in cancer drug therapy and to develop novel therapies aimed at regulating P2 receptor activity.

Inhibitory Effects of ATP and Adenosine on Cholangiocarcinoma Cell Proliferation and Motility

“…In addition, ATP at a very high dose in the range of milli molar was reported to induce cytotoxicity and apoptosis in many cancer types such as hepatoma, adenocarcinoma, and cervical cancer cells (24,(30)(31)(32)(33). On the other hand, some studies have showed that 10 μM ATP and lower doses stimulated growth and motility of ovarian cancer (34), hepatoma (19), breast cancer (23), lung cancer (25), and prostate cancer cells (20,35). To utilize ATP and/or adenosine in vivo, one must consider the final dose of the compounds at the tumor sites.…”

The loss of P2X7 receptor expression leads to increase intestinal glucose transit and hepatic steatosis

“…Total RNA was isolated from the liver of 12-week-old mice using the ToTALLY RNA Total RNA Isolation Kit (Thermo Fisher Scientific) and RNA purified Qiagen RNeasy minikit (Qiagen, Toronto, ON). Complementary DNA was synthesized from 2 μg of purified RNA as previously described 63 . Quantitative real-time PCR analyses were realized as previously reported 63 using the mouse sequence-specific primers for Acaca : 5′-GATGAACCATCTCCGTTGCG-3′ and 5′-GAGCCAATTATGAATCG GGACTG-3′, Acacb : 5′-TTCCCCAGCCAGCAGATAGC-3′ and 5′-CTTCATGTAGCCACGGGTCC-3′, Fasn : 5′-GATGAAGAGGGACCATAAAGAATAA-3′ and 5′-GCACTTGATGTGAG GGGAGAT3′, Acox1 : 5′-CCGCCACCTTCAATCCAGAG-3′ and 5′-CAAGTTCTCGATTTCTCGACGG-3′, and Mlxipl : 5′-CTGGGGACCTAAACAGGAGC-3′ and 55′-GAAGCCACCCTATAGCTCCC-3′.…”

“…Complementary DNA was synthesized from 2 μg of purified RNA as previously described 63 . Quantitative real-time PCR analyses were realized as previously reported 63 using the mouse sequence-specific primers for Acaca : 5′-GATGAACCATCTCCGTTGCG-3′ and 5′-GAGCCAATTATGAATCG GGACTG-3′, Acacb : 5′-TTCCCCAGCCAGCAGATAGC-3′ and 5′-CTTCATGTAGCCACGGGTCC-3′, Fasn : 5′-GATGAAGAGGGACCATAAAGAATAA-3′ and 5′-GCACTTGATGTGAG GGGAGAT3′, Acox1 : 5′-CCGCCACCTTCAATCCAGAG-3′ and 5′-CAAGTTCTCGATTTCTCGACGG-3′, and Mlxipl : 5′-CTGGGGACCTAAACAGGAGC-3′ and 55′-GAAGCCACCCTATAGCTCCC-3′. Gene expression was normalized to Tbp gene expression as previously reported 64 .…”

Drug resistance and combating drug resistance in cancer

“…Purinergic signaling has been known to promote cell growth and proliferation [182,183] . Purinergic receptors such as members of the P2X and P2Y families were reported to be involved in cancer drug resistance [184][185][186] . In one recent study, researchers demonstrated that ATP promoted resistance to chemotherapeutic drugs in colorectal cancer cells through P2Y-mediated upregulation of MRP2 and concurrent drug pumping [187] .…”