Methotrexate (MTX) and mycophenolic acid (MPA) are used in the clinic for their immunosuppressive properties. MTX is widely used for the treatment of rheumatoid arthritis (RA). MPA is used to prevent graft rejection and is now experimentally used in systemic lupus erythematosis and RA. It is known that both drugs interfere with DNA synthesis. However, the precise mechanism of action is still debated. We have analysed the effect of the drugs on cytokine production in whole blood during short cultures. The production of T‐cell cytokines was inhibited by both drugs. MTX inhibits cytokine production because MTX induces apoptosis in activated T‐cells. MPA inhibits cytokine production by preventing T‐cells to progress to the S‐phase of the cell cycle. Cytokine production by monocytes was slightly decreased by the drugs. The reason for this inhibition is not clear. These results indicate that T‐cells are the main target cells of the immunosuppressive drugs MPA and MTX. 相似文献
The present study examined the therapeutic effects of bone marrow mesenchymal stem cells (BM‐MSCs) and adipose‐derived mesenchymal stem cells (AD‐MSCs) in methotrexate (MTX)‐induced pulmonary fibrosis in rats as compared with dexamethasone (Dex). MTX (14 mg/kg, as a single dose/week for 2 weeks, p.o.) induced lung fibrosis as marked by elevation of relative lung weight, malondialdehyde, nitrite/nitrate, interleukin‐4, transforming growth factor‐β1, deposited collagen, as well as increased expression of Bax along with the reduction of reduced glutathione content and superoxide dismutase activity. These deleterious effects were antagonized after treatment either with BM‐MSCs or AD‐MSCs (2 × 106 cells/rat) 2 weeks after MTX to even a better extent than Dex (0.5 mg/kg/ for 7 days, p.o.). In conclusion, BM‐MSC and AD‐MSCs possessed antioxidant, antiapoptotic, as well as antifibrotic effects, which will probably introduce them as remarkable candidates for the treatment of pulmonary fibrosis. 相似文献
Glioblastoma (GBM) is the most malignant and deadly brain tumor. GBM cells overexpress the CD73 enzyme, which controls the level of extracellular adenosine, an immunosuppressive molecule. Studies have shown that some nonsteroidal anti-inflammatory drugs (NSAIDs) and methotrexate (MTX) have antiproliferative and modulatory effects on CD73 in vitro and in vivo. However, it remains unclear whether the antiproliferative effects of MTX and NSAIDS in GBM cells are mediated by increases in CD73 expression and adenosine formation. The aim of this study was to evaluate the effect of the NSAIDs, naproxen, piroxicam, meloxicam, ibuprofen, sodium diclofenac, acetylsalicylic acid, nimesulide, and ketoprofen on CD73 expression in GBM and mononuclear cells. In addition, we sought to understand whether the effects of MTX may be mediated by CD73 expression and activity. Cell viability and CD73 expression were evaluated in C6 and mononuclear cells after exposure to NSAIDs. For analysis of the mechanism of action of MTX, GBM cells were treated with APCP (CD73 inhibitor), dipyridamole (inhibitor of adenosine uptake), ABT-702 (adenosine kinase enzyme inhibitor), or caffeine (P1 adenosine receptor antagonist), before treatment with MTX and AMP, in the presence or not of mononuclear cells. In summary, only MTX increased the expression of CD73 in GBM cells decreasing cells viability by mechanisms independent of the adenosinergic system. Further studies are needed to understand the role of MTX in the GBM microenvironment.
It has been reported that 3-D cultures of hepatocytes or HepG2 cells were less susceptible to methotrexate (MTX) than their 2-D counterparts. Such a mechanism was addressed in this study by investigation of MTX hepatotoxicity in gel entrapped (3-D) rat hepatocytes vs. traditional monolayer culture (2-D). Similarly, gel entrapped hepatocytes showed higher drug resistance to MTX than hepatocyte monolayers in whatever culture medium with or without modification by hormone supplements (dexamethasone, glucagon and insulin). It was also found that medium modification by hormones greatly increased drug resistance of hepatocyte monolayers but has only a slight effect on 3-D cultured hepatocytes. These differential MTX toxicities regarding culture medium and culture models were assumed to correlate with multidrug resistance associated protein 2 (Mrp2). The involvement of Mrp2 was confirmed directly by the fact that MTX intracellularly accumulated less in gel entrapped hepatocytes than in hepatocyte monolayer but could be enhanced by Mrp2 inhibitors accompanied by reduced drug resistance. Furthermore, the expression of Mrp2 on gene level and transportation activity together with bile-duct-like structure were more significantly evidenced in 3-D gel entrapment culture than in 2-D monolayer culture. In conclusion, the highly preserved Mrp2 in 3-D gel entrapped hepatocytes determines its high drug resistance to MTX. Gel entrapped hepatocytes could be useful for investigation of hepatic transportation and hepatotoxicity. 相似文献
We report here a new selectable marker for tobacco immature pollen transformation based on the expression of dihydrofolate
reductase (dhfr) gene which confers resistance to methotrexate (Mtx). Two immature pollen transformation approaches, i.e., male germ line
transformation and particle bombardment of embryogenic mid-bicellular pollen have been used for the production of stable transgenic
tobacco plants. In the first method, two methotrexate-resistant plants were selected from a total of 7161 seeds recovered
after transformation experiments. In the second method, four methotrexate-resistant plants were obtained from 29 bombardments
using 3.7×105 pollen grains per bombardment. Southern analysis confirmed the transgenic nature of T0 and T1 candidate transgenic plants, and a genetic analysis showed that the transgenes are transmitted to subsequent generations. 相似文献
Overexpression of HER2/neu is associated with drug resistance and poor outcome in breast cancer. Solamargine (SM), a glycoalkaloid
purified from the herb Solanum incanum, exhibits HER2/neu gene modulation of HER2/neu high-expressing human breast cancer cell line ZR-75-1. SM downregulation
of HER2/neu gene expression was determined by RT-PCR and Southern hybridization. Additionally, the membrane-bound HER2/neu
receptor in highly HER2/neu-expressing breast cancer cells was determined by radioimmunoassay, immunocytochemistry, fluorescent
immunocytochemistry, and flow cytometry. SM significantly decreased the number of HER2/neu receptors on the cell membrane.
Methotrexate (MTX), 5-florouracil (5-Fu), and cisplatin (CDDP) are commonly used for breast carcinoma treatment in clinics;
however, patients with HER2/neu overexpression exhibit resistance to these anticancer drugs. Notably, combination of MTX,
5-Fu, and CDDP with SM individually increased the susceptibility of breast cancer cells to these chemotherapeutic agents.
Experimental results indicated that downregulation of HER2/neu by SM might be an effective strategy for enhancing drug susceptibility
of breast cancer cells expressing high levels of HER2/neu. 相似文献
Although heat shock protein Hsp72 confers resistance to oxidative injury, the mechanisms are unknown. These studies demonstrate that Hsp72 protects dihydrofolate reductase (DHFR) against injury caused by the thiol oxidant monochloramine (NH(2)Cl). When exposed to NH(2)Cl, DHFR catalytic activity is impaired and SDS-PAGE migration retarded. These may be blocked by prior addition of Hsp72 or the folate analog methotrexate. Methotrexate binding to DHFR is diminished by oxidant treatment, preventable by prior Hsp72 incubation. Hsp72 also protects DHFR in IEC-18 cells following oxidant exposure. Hsp72 co-immunoprecipitates with DHFR, especially after partial oxidation. The DHFR-Hsp72 interaction is modulated by cofactor/substrate binding for both Hsp72 (ATP) and DHFR (methotrexate). Thiol oxidation of DHFR increases susceptibility for tryptic proteolysis. Preincubation of DHFR with Hsp72 prevents the NH(2)Cl-induced sensitivity to proteolysis. Thus, Hsp72 binds DHFR through enhanced protein-chaperone interactions upon oxidant exposure, a process that may protect against irreversible modification of DHFR catalytic and structural integrity. 相似文献