FKBP12; calcineurin; macrocyclic lactone

FK-506 和环孢菌素 A 阻断细胞质成分的易位，而不影响 T 淋巴细胞核亚基的合成。 [1] K-506 抑制 Ca(2+) 依赖性过程，该过程是诱导白细胞介素 2 转录所必需的，从而阻止 T 细胞增殖。 [2] 亲环蛋白和 FK 506 结合蛋白 (FKBP) 是 FK 506 结合的两个不同的细胞内蛋白（亲免蛋白）家族。在阻止激活的 T 细胞产生白细胞介素 2 的药物浓度下，FK-506 特异性抑制细胞钙调神经磷酸酶。 [3] 通过阻断涉及淋巴因子表达、细胞凋亡和脱颗粒的早期钙相关事件的相同子集，FK-506 和 CsA 对细胞具有几乎相同的生物学效应。 FK-506 结合蛋白 (FKBP) 是细胞内受体家族，是 FK-506 结合的地方。 [4]

对大鼠针对痛觉过敏和异常性疼痛刺激的行为疼痛评估显示，FK-506 会导致爪子和尾巴缩回阈值增加。此外，FK-506 还可降低血清硝酸盐和硫代巴比妥酸反应物质 (TBARS) 水平。它还可以降低大鼠组织髓过氧化物酶 (MPO) 和总钙水平，同时提高组织还原型谷胱甘肽水平。在缺血再灌注 (I/R) 大鼠中，FK-506 可以减少神经元水肿和轴突变性的进展。 [5]

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本研究旨在阐明他克莫司（FK506）和C-X-C趋化因子受体4型（CXCR4）对肝细胞癌（HCC）生长和转移的影响，CXCR4是基质细胞衍生因子-1α（SDF-1α）的特异性受体。用不同浓度的FK506、AMD3100或生理盐水（NS）处理后，通过MTT法测量Morris大鼠肝癌3924A（MH3924A）细胞的增殖，用免疫组织化学分析CXCR4的表达，分别用transwell法和扫描电镜研究细胞的形态变化和侵袭性。此外，使用August Copenhagen Irish大鼠模型植入肿瘤，通过免疫组织化学检测肿瘤的体内病理变化和侵袭性、肿瘤组织中CXCR4的表达以及HCC邻近组织中SDF-1α的表达。在体外实验中，FK506（100‑1000µg/l）显著促进了MH3924A细胞的增殖（P<0.01），并增加了MH39224A细胞中CXCR4的表达，但没有显著意义（P>0.05）。相比之下，AMD3100对MH3924A细胞的增殖没有影响，但显著降低了CXCR4的表达（P<0.05）。FK506、SDF-1α、FK506+AMD3100、FK506+SDF-1α或FK506+AMDA3100+SDF-1β处理后，MH3924A细胞的侵袭性显著增强（P<0.01）。在体内，FK506治疗组和NS组的肿瘤重量（P=0.041）、淋巴结转移（P=0.002）、肺结节数量（P=0.012）、肿瘤组织中CXCR4的表达（P=0.048）和邻近组织中SDF-1α的表达（=0.026）存在显著差异。研究结果表明，FK506在体内促进MH3924A细胞的增殖以及CXCR4和SDF-1α的表达。因此，抑制CXCR4/SDF-1α复合物的形成可能会部分降低FK506对HCC的促进作用[4]。

他克莫司 (FK506) 抑制钙依赖性事件，例如 IL-2 基因转录、NO 合酶激活、细胞脱颗粒和细胞凋亡。他克莫司还通过与激素受体复合物中包含的 FKBP 结合，防止降解，从而增强糖皮质激素和黄体酮的作用。该药物可以以与 CsA 类似的方式增强 TGFβ-1 基因的表达。他克莫司抑制 T 细胞受体连接后的 T 细胞增殖。低浓度他克莫司(FK506,10 μg/L)处理对MH3924A细胞的增殖没有显着影响(P=0.135)。高浓度他克莫司（100-1,000 μg/L）处理后，MH3924A细胞增殖显着增强（P<0.01）。但不同浓度的AMD3100与100 μg/L他克莫司合用时，MH3924A细胞体外增殖能力增强（P<0.01）。

细胞处理和裂解。将免疫抑制剂以比细胞处理所需浓度高1000倍的浓度溶解在乙醇中。将细胞（106）悬浮在微量离心管中的1ml完全培养基中；加入1 Al乙醇或FK 506、CsA或雷帕霉素的乙醇溶液，将细胞在37°C下孵育1小时。用1 ml冰上磷酸盐缓冲盐水（PBS）洗涤细胞两次，并在50μl含50 mM Tris（pH 7.5）的低渗缓冲液中裂解；0.1mM EGTA；1mM EDTA；0.5mM二硫苏糖醇；以及每毫升50微克苯甲基磺酰氟、50克大豆胰蛋白酶抑制剂、5克亮肽和5微克抑肽酶。将裂解物在液氮中冷冻三个循环，然后在30°C下解冻，然后在4°C下以12000 x g的速度离心10分钟。[3]

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白细胞介素2（IL-2）检测。Jurkat细胞在96孔平底板中以每毫升106个细胞的速度在完全培养基中培养。在有或没有FK 506或CsA的情况下，用OKT3单克隆抗体（腹水1:4000稀释液）和每毫升2ng佛波醇12-肉豆蔻酸13-乙酸酯（PMA）刺激细胞24小时。通过测量细胞上清液的连续稀释液支持IL-2依赖性细胞系CTLL-20增殖的能力来定量IL-2的产生。一个单位定义为诱导CTLL-20细胞半最大增殖所需的重组人IL-2的量<直接添加到CTLL-20细胞中的FK 506和CsA不会抑制IL-2依赖性增殖。[3]

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免疫抑制剂环孢菌素A（CsA）和FK 506结合不同的细胞内蛋白家族（亲免疫蛋白），称为亲环蛋白和FK 506-结合蛋白（FKBPs）。最近，有研究表明，在体外，CsA-亲环素和FK 506-FKBP-12的复合物结合并抑制钙依赖性丝氨酸/苏氨酸磷酸酶钙调神经磷酸酶的活性。我们研究了药物治疗对T淋巴细胞磷酸酶活性的影响。钙调神经磷酸酶在T细胞中表达，其活性可以在细胞裂解物中测量。在抑制活化T细胞中白细胞介素2产生的药物浓度下，CsA和FK 506都特异性抑制细胞钙调神经磷酸酶。雷帕霉素与FKBP结合，但表现出与FK506不同的生物活性，对钙调神经磷酸酶活性没有影响。此外，过量浓度的雷帕霉素明显通过从FKBP中置换FK506来阻止FK506的作用。这些结果表明，钙调神经磷酸酶是体内药物亲免疫素复合物的靶标，并确立了钙调神经蛋白酶在T细胞活化中的生理作用。[3]

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细胞在10nM FK 506存在下培养1小时并洗涤，测定裂解物中的磷酸酶活性。

Mice; Six-week-old male C57BL/6J mice are maintained in a temperature- and humidity-controlled room with a 12-h light-dark cycle. FTacrolimus 30 mg/kg is given orally to colitic mice (n=10) for either 7 or 14 days (Days 10 to 23) as part of the multiple dosing study. The same regimen is used to administer placebos to the control group (n = 10) and the normal group (n = 5). 10 mL/kg of placebo or tacrolimus is given. On the day after the final dose, mice are put to death by CO2 inhalation. For the single-dose study, colitic mice are given Tacrolimus or a placebo (n=8) orally once on Days 7, 10, 17, or 24. The same procedure is used to administer a placebo to normal mice (n = 4). Eight hours after dosing, mice are put to death by CO2 inhalation.

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We investigated the effect of tacrolimus, a calcineurin inhibitor, on dextran sulfate sodium (DSS)-induced colitis. After inducing colitis in C57BL/6 mice by administering DSS solution as drinking water for 7 d, the animals were treated with tacrolimus. Severity of colonic inflammation was evaluated based on colon weight per unit length. Levels of cytokines (interferon (IFN)-γ, interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-12, and tumor necrosis factor (TNF)-α) released from isolated inflamed colons of mice treated with tacrolimus or vehicle were also measured. Treatment with tacrolimus for 14 d reduced the colon weight per unit length and suppressed the release of IFN-γ and IL-1β, but not other cytokines, in inflamed colons of colitic mice compared with vehicle-treated mice. A positive correlation was noted between colon weight per unit length and released level of IFN-γ or IL-1β. The release of IFN-γ and IL-1β was also suppressed after single dosing with tacrolimus to colitic mice. Taken together, these results suggested that tacrolimus ameliorated DSS-induced colitis by suppressing release of IFN-γ and IL-1β from inflamed colon.[4]

Absorption, Distribution and Excretion
Absorption of tacrolimus from the gastrointestinal tract after oral administration is incomplete and variable. The absolute bioavailability in adult kidney transplant patients is 17±10%; in adults liver transplant patients is 22±6%; in healthy subjects is 18±5%. The absolute bioavailability in pediatric liver transplant patients was 31±24%. Tacrolimus maximum blood concentrations (Cmax) and area under the curve (AUC) appeared to increase in a dose-proportional fashion in 18 fasted healthy volunteers receiving a single oral dose of 3, 7, and 10 mg. When given without food, the rate and extent of absorption were the greatest. The time of the meal also affected bioavailability. When given immediately after a meal, mean Cmax was reduced 71%, and mean AUC was reduced 39%, relative to the fasted condition. When administered 1.5 hours following the meal, mean Cmax was reduced 63%, and mean AUC was reduced 39%, relative to the fasted condition.
In man, less than 1% of the dose administered is excreted unchanged in urine. When administered IV, fecal elimination accounted for 92.6±30.7%, urinary elimination accounted for 2.3±1.1%.
2.6 ± 2.1 L/kg [pediatric liver transplant patients]
1.07 ± 0.20 L/kg [patients with renal impairment, 0.02 mg/kg/4 hr dose, IV]
3.1 ± 1.6 L/kg [Mild Hepatic Impairment, 0.02 mg/kg/4 hr dose, IV]
3.7 ± 4.7 L/kg [Mild Hepatic Impairment, 7.7 mg dose, PO]
3.9 ± 1.0 L/kg [Severe hepatic impairment, 0.02 mg/kg/4 hr dose, IV]
3.1 ± 3.4 L/kg [Severe hepatic impairment, 8 mg dose, PO]
0.040 L/hr/kg [healthy subjects, IV]
0.172 ± 0.088 L/hr/kg [healthy subjects, oral]
0.083 L/hr/kg [adult kidney transplant patients, IV]
0.053 L/hr/kg [adult liver transplant patients, IV]
0.051 L/hr/kg [adult heart transplant patients, IV]
0.138 ± 0.071 L/hr/kg [pediatric liver transplant patients]
0.12 ± 0.04 (range 0.06-0.17) L/hr/kg [pediatric kidney transplant patients]
0.038 ± 0.014 L/hr/kg [patients with renal impairment, 0.02 mg/kg/4 hr dose, IV]
0.042 ± 0.02 L/hr/kg [Mild Hepatic Impairment, 0.02 mg/kg/4 hr dose, IV]
0.034 ± 0.019 L/hr/kg [Mild Hepatic Impairment, 7.7 mg dose, PO]
0.017 ± 0.013 L/hr/kg [Severe hepatic impairment, 0.02 mg/kg/4 hr dose, IV]
0.016 ± 0.011 L/hr/kg [Severe hepatic impairment, 8 mg dose, PO]
The aim of this study was to assess tacrolimus levels in breast milk and neonatal exposure during breastfeeding. An observational cohort study was performed in two tertiary referral high-risk obstetric medicine clinics. Fourteen women taking tacrolimus during pregnancy and lactation, and their 15 infants, 11 of whom were exclusively breast-fed, were assessed. Tacrolimus levels were analyzed by liquid chromatography-tandem mass spectrometry. Samples from mothers and cord blood were collected at delivery and from mothers, infants, and breast milk postnatally where possible. All infants with serial sampling had a decline in tacrolimus level, which was approximately 15% per day (ratio of geometric mean concentrations 0.85; 95% confidence interval, 0.82-0.88; P<0.001). Breast-fed infants did not have higher tacrolimus levels compared with bottle-fed infants (median 1.3 ug/L [range, 0.0-4.0] versus 1.0 ug/L (range, 0.0-2.3), respectively; P=0.91). Maximum estimated absorption from breast milk is 0.23% of maternal dose (weight-adjusted). Ingestion of tacrolimus by infants via breast milk is negligible. Breastfeeding does not appear to slow the decline of infant tacrolimus levels from higher levels present at birth.
Maternal and umbilical cord (venous and arterial) samples were obtained at delivery from eight solid organ allograft recipients to measure tacrolimus and metabolite bound and unbound concentrations in blood and plasma. Tacrolimus pharmacokinetics in breast milk were assessed in one subject. Mean (+ or - SD) tacrolimus concentrations at the time of delivery in umbilical cord venous blood (6.6 + or - 1.8 ng ml(-1)) were 71 + or - 18% (range 45-99%) of maternal concentrations (9.0 + or - 3.4 ng ml(-1)). The mean umbilical cord venous plasma (0.09 + or - 0.04 ng ml(-1)) and unbound drug concentrations (0.003 + or - 0.001 ng ml(-1)) were approximately one fifth of the respective maternal concentrations. Arterial umbilical cord blood concentrations of tacrolimus were 100 + or - 12% of umbilical venous concentrations. In addition, infant exposure to tacrolimus through the breast milk was less than 0.3% of the mother's weight-adjusted dose. Differences between maternal and umbilical cord tacrolimus concentrations may be explained in part by placental P-gp function, greater red blood cell partitioning and higher haematocrit levels in venous cord blood.
Ten colostrum samples were obtained from six women in the immediate postpartum period (0-3 days) with a mean drug concentration of 0.79 ng/mL (range 0.3-1.9 ng/mL). The median milk:maternal plasma ratio was 0.5.
The plasma protein binding of tacrolimus is approximately 99% and is independent of concentration over a range of 5-50 ng/mL. Tacrolimus is bound mainly to albumin and alpha-1-acid glycoprotein, and has a high level of association with erythrocytes. The distribution of tacrolimus between whole blood and plasma depends on several factors, such as hematocrit, temperature at the time of plasma separation, drug concentration, and plasma protein concentration. In a US study, the ratio of whole blood concentration to plasma concentration averaged 35 (range 12 to 67). There was no evidence based on blood concentrations that tacrolimus accumulates systemically upon intermittent topical application for periods of up to 1 year. As with other topical calcineurin inhibitors, it is not known whether tacrolimus is distributed into the lymphatic system.
For more Absorption, Distribution and Excretion (Complete) data for Tacrolimus (9 total), please visit the HSDB record page.

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Metabolism / Metabolites
The metabolism of tacrolimus is predominantly mediated by CYP3A4 and secondarily by CYP3A5. Tacrolimus is metabolized into 8 metabolites: 13-demethyl tacrolimus, 31-demethyl tacrolimus, 15-demethyl tacrolimus, 12-hydroxy tacrolimus, 15,31-didemethyl tacrolimus, 13,31-didemethyl tacrolimus, 13,15-didemethyl tacrolimus, and a final metabolite involving O-demethylation and the formation of a fused ring. The major metabolite identified in incubations with human liver microsomes is 13-demethyl tacrolimus. In in vitro studies, a 31-demethyl metabolite has been reported to have the same activity as tacrolimus.
Tacrolimus is extensively metabolized by the mixed-function oxidase system, primarily the cytochrome P-450 system (CYP3A). A metabolic pathway leading to the formation of 8 possible metabolites has been proposed. Demethylation and hydroxylation were identified as the primary mechanisms of biotransformation in vitro. The major metabolite identified in incubations with human liver microsomes is 13-demethyl tacrolimus. In in vitro studies, a 31-demethyl metabolite has been reported to have the same activity as tacrolimus.
Fk_506 has known human metabolites that include 13-O-Desmethyltacrolimus and 15-O-Desmethyltacrolimus.

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Biological Half-Life
The elimination half life in adult healthy volunteers, kidney transplant patients, liver transplants patients, and heart transplant patients are approximately 35, 19, 12, 24 hours, respectively. The elimination half life in pediatric liver transplant patients was 11.5±3.8 hours, in pediatric kidney transplant patients was 10.2±5.0 (range 3.4-25) hours.
In a mass balance study of IV administered radiolabeled tacrolimus to 6 healthy volunteers, ... the elimination half-life based on radioactivity was 48.1+ or - 15.9 hours whereas it was 43.5 + or- 11.6 hours based on tacrolimus concentrations. ... When administered PO, the elimination half-life based on radioactivity was 31.9 + or- 10.5 hours whereas it was 48.4 + or - 12.3 hours based on tacrolimus concentrations ... .
... A case of tacrolimus toxicity in a non-transplant patient /is presented/. ... /The/ patient's tacrolimus dose was 2.1 mg/kg/day for 4 days (therapeutic 0.03 to 0.05 mg/kg/day). Her tacrolimus elimination half-life was 16.5 hours, compared to a mean half-life in healthy volunteers of 34.2 +/- 7.7 hours. ...

Toxicity Summary
IDENTIFICATION AND USE: Tacrolimus is white to off-white crystalline powder. It is a calcineurin-inhibitor immunosuppressant available in several preparations. Tacrolimus in both oral capsules and a solution for IV injection is used for prophylaxis of organ rejection in patients receiving liver, kidney or heart transplants. Tacrolimus topical ointment is used as a second-line therapy for the short-term and non-continuous chronic treatment of moderate to severe atopic dermatitis in non-immunocompromised adults and children. HUMAN EXPOSURE AND TOXICITY: While most acute overdosages of tacrolimus at up to 30 times the intended dose have been asymptomatic and all patients recovered with no sequelae, some acute overdosages were followed by adverse reactions including tremors, abnormal renal function, hypertension, and peripheral edema. At therapeutic doses, patients receiving tacrolimus are at increased risk of developing lymphomas and other malignancies, particularly of the skin, as well as an increased risk of developing bacterial, viral, fungal, and protozoal infections, including opportunistic infections. These infections may lead to serious, including fatal, outcomes. While there are no adequate and well-controlled studies in pregnant women, the use of tacrolimus during pregnancy in humans has been associated with neonatal hyperkalemia and renal dysfunction. ANIMAL STUDIES: Both rats and baboons showed a similar toxicologic profile following oral or intravenous administration of tacrolimus. Toxicity following intravenous administration was evident at lower doses than after oral administration for both rats and baboons. Toxicity was seen at lower doses in rats than in baboons. The primary target organs were the kidneys, pancreatic islets of Langerhans and exocrine pancreas, spleen, thymus, gastrointestinal tract, and lymph nodes. In addition, decreases in erythrocyte parameters were seen. Tacrolimus also produced reproductive and developmental toxicity in both rats and rabbits. In rats, chronic oral administration of tacrolimus at high doses resulted in changes in sex organs, and glaucoma/eye changes. Oral doses of tacrolimus at 1 and 3.2 mg/kg/day produced overt signs of parental toxicity and changes in the fertility and general reproductive performance of rats. Effects on reproduction included some embryo lethality, reduced number of implantations, increased incidence of post-implantation loss, and reduced embryo and offspring viability. In a rabbit teratology study, signs of maternal toxicity including reduced body weight were produced at all oral doses of tacrolimus administered (0.1, 0.32, or 1 mg/kg/day). Doses of 0.32 and 1 mg/kg/day produced signs of developmental toxicity, such as increased incidence of post-implantation losses, reduced number of viable fetuses, and increased incidences of morphological variations. In a rat teratology study, increased post-implantation loss was observed at 3.2 mg/kg/day. Maternal doses of 1 mg/kg/day decreased the body weight of F1 offspring. Decreased body weight, reduced survival number, and some skeletal alterations were seen in F1 offspring at maternal doses of 3.2 mg/kg/day. Tacrolimus did not exhibit genotoxic activity in vitro in bacterial asaays in Salmonella typhimurium and Escherichia coli or mammalian assays in Chinese hamster lung-derived cells assays. No evidence of mutagenicity was observed in vitro in the CHO/HGPRT assay (the Chinese hamster ovary cell assay (CHO), which measures forward mutation of the HGPRT locus) or in vivo in clastogenicity assays performed in mice. Tacrolimus also did not cause unscheduled DNA synthesis in rodent hepatocytes.

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Interactions
With a given dose of mycophenolic acid (MPA) products, exposure to MPA is higher with Prograf co-administration than with cyclosporine co-administration because cyclosporine interrupts the enterohepatic recirculation of MPA while tacrolimus does not. Clinicians should be aware that there is also a potential for increased MPA exposure after crossover from cyclosporine to Prograf in patients concomitantly receiving MPA-containing products.
Grapefruit juice inhibits CYP3A-enzymes resulting in increased tacrolimus whole blood trough concentrations, and patients should avoid eating grapefruit or drinking grapefruit juice with tacrolimus.
Since tacrolimus is metabolized mainly by CYP3A enzymes, drugs or substances known to inhibit these enzymes may increase tacrolimus whole blood concentrations. Drugs known to induce CYP3A enzymes may decrease tacrolimus whole blood concentrations. Dose adjustments may be needed along with frequent monitoring of tacrolimus whole blood trough concentrations when Prograf is administered with CYP3A inhibitors or inducers. In addition, patients should be monitored for adverse reactions including changes in renal function and QT prolongation.
Verapamil, diltiazem, nifedipine, and nicardipine inhibit CYP3A metabolism of tacrolimus and may increase tacrolimus whole blood concentrations. Monitoring of whole blood concentrations and appropriate dosage adjustments of tacrolimus are recommended when these calcium channel blocking drugs and tacrolimus are used concomitantly.
For more Interactions (Complete) data for Tacrolimus (18 total), please visit the HSDB record page.

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Non-Human Toxicity Values
LD50 Rat iv 23,600 ug/kg /Tacrolimus hydrate/
LD50 Rat oral 134 mg/kg /Tacrolimus hydrate/

[1]. Nature. 1991 Aug 29;352(6338):803-7.

[2]. Nature. 1992 Jun 25;357(6380):692-4.

[3]. Proc Natl Acad Sci U S A. 1992 May 1;89(9):3686-90.

[4]. Tacrolimus promotes hepatocellular carcinoma and enhances CXCR4/SDF 1α expression in vivo. Mol Med Rep. 2014 Aug;10(2):585-92.

Therapeutic Uses
Immunosuppressive Agents
Prograf is indicated for the prophylaxis of organ rejection in patients receiving allogeneic kidney transplants. It is recommended that Prograf be used concomitantly with azathioprine or mycophenolate mofetil (MMF) and adrenal corticosteroids. /Included in US product label/
Prograf is indicated for the prophylaxis of organ rejection in patients receiving allogeneic liver transplants. It is recommended that Prograf be used concomitantly with adrenal corticosteroids. Therapeutic drug monitoring is recommended for all patients receiving Prograf. /Included in US product label/
Prograf is indicated for the prophylaxis of organ rejection in patients receiving allogeneic heart transplants. It is recommended that Prograf be used concomitantly with azathioprine or mycophenolate mofetil (MMF) and adrenal corticosteroids. /Included in US product label/
For more Therapeutic Uses (Complete) data for Tacrolimus (13 total), please visit the HSDB record page.

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Drug Warnings
/BOXED WARNING/ MALIGNANCIES AND SERIOUS INFECTIONS. Increased risk of development of lymphoma and other malignancies, particularly of the skin, due to immunosuppression. Increased susceptibility to bacterial, viral, fungal, and protozoal infections, including opportunistic infections. Only physicians experienced in immunosuppressive therapy and management of organ transplant patients should prescribe Prograf. Patients receiving the drug should be managed in facilities equipped and staffed with adequate laboratory and supportive medical resources. The physician responsible for maintenance therapy should have complete information requisite for the follow-up of the patient.
/BOXED WARNING/ WARNING: Long-term Safety of Topical Calcineurin Inhibitors Has Not Been Established Although a causal relationship has not been established, rare cases of malignancy (e.g., skin and lymphoma) have been reported in patients treated with topical calcineurin inhibitors, including Protopic Ointment. Therefore: Continuous long-term use of topical calcineurin inhibitors, including Protopic Ointment, in any age group should be avoided, and application limited to areas of involvement with atopic dermatitis; Protopic Ointment is not indicated for use in children less than 2 years of age; Only 0.03% Protopic Ointment is indicated for use in children 2-15 years of age.
Topical tacrolimus therapy should be avoided for malignant or premalignant skin conditions (e.g., cutaneous T-cell lymphoma (CTCL)), which may appear clinically similar to dermatitis.
Because of a potential increased risk for skin cancer, patients /using topical tacrolimus/ should be advised to limit exposure to sunlight or other UV light by wearing protective clothing and using a broad-spectrum sunscreen with a high protection factor.
For more Drug Warnings (Complete) data for Tacrolimus (42 total), please visit the HSDB record page.

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Pharmacodynamics
Tacrolimus acts by reducing peptidyl-prolyl isomerase activity by binding to the immunophilin FKBP-12 (FK506 binding protein) creating a new complex. This inhibits both T-lymphocyte signal transduction and IL-2 transcription. Tacrolimus has similar activity to cyclosporine but rates of rejection are lower with tacrolimus. Tacrolimus has also been shown to be effective in the topical treatment of eczema, particularly atopic eczema. It suppresses inflammation in a similar way to steroids, but is not as powerful. An important dermatological advantage of tacrolimus is that it can be used directly on the face; topical steroids cannot be used on the face, as they thin the skin dramatically there. On other parts of the body, topical steroid are generally a better treatment.

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Cyclosporin A and FK506 inhibit T- and B-cell activation and other processes essential to an effective immune response. In T lymphocytes these drugs disrupt an unknown step in the transmission of signals from the T-cell antigen receptor to cytokine genes that coordinate the immune response. The putative intracellular receptors for FK506 and cyclosporin are cis-trans prolyl isomerases. Binding of the drug inhibits isomerase activity, but studies with other prolyl isomerase inhibitors and analysis of cyclosporin-resistant mutants in yeast suggest that the effects of the drug result from the formation of an inhibitory complex between the drug and isomerase, and not from inhibition of isomerase activity. A transcription factor, NF-AT, which is essential for early T-cell gene activation, seems to be a specific target of cyclosporin A and FK506 action because transcription directed by this protein is blocked in T cells treated with these drugs, with little or no effect on other transcription factors such as AP-1 and NF-kappa B. Here we demonstrate that NF-AT is formed when a signal from the antigen receptor induces a pre-existing cytoplasmic subunit to translocate to the nucleus and combine with a newly synthesized nuclear subunit of NF-AT. FK506 and cyclosporin A block translocation of the cytoplasmic component without affecting synthesis of the nuclear subunit. [1]

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Antigen recognition by the T-cell receptor (TCR) initiates events including lymphokine gene transcription, particularly interleukin-2, that lead to T-cell activation. The immunosuppressive drugs, cyclosporin A (CsA) and FK-506, prevent T-cell proliferation by inhibiting a Ca(2+)-dependent event required for induction of interleukin-2 transcription. Complexes of FK-506 or CsA and their respective intracellular binding proteins inhibit the calmodulin-dependent protein phosphatase, calcineurin, in vitro. The pharmacological relevance of this observation to immunosuppression or drug toxicity is undetermined. Calcineurin, although present in lymphocytes, has not been implicated in TCR-mediated activation of lymphokine genes or in transcriptional regulation in general. Here we report that transfection of a calcineurin catalytic subunit increases the 50% inhibitory concentration (IC50) of the immunosuppressants FK-506 and CsA, and that a mutant subunit acts in synergy with phorbol ester alone to activate the interleukin-2 promoter in a drug-sensitive manner. These results implicate calcineurin as a component of the TCR signal transduction pathway by demonstrating its role in the drug-sensitive activation of the interleukin-2 promoter.[2]

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The immunosuppressive agents cyclosporin A (CsA) and FK 506 bind to distinct families of intracellular proteins (immunophilins) termed cyclophilins and FK 506-binding proteins (FKBPs). Recently, it has been shown that, in vitro, the complexes of CsA-cyclophilin and FK 506-FKBP-12 bind to and inhibit the activity of calcineurin, a calcium-dependent serine/threonine phosphatase. We have investigated the effects of drug treatment on phosphatase activity in T lymphocytes. Calcineurin is expressed in T cells, and its activity can be measured in cell lysates. Both CsA and FK 506 specifically inhibit cellular calcineurin at drug concentrations that inhibit interleukin 2 production in activated T cells. Rapamycin, which binds to FKBPs but exhibits different biological activities than FK 506, has no effect on calcineurin activity. Furthermore, excess concentrations of rapamycin prevent the effects of FK 506, apparently by displacing FK 506 from FKBPs. These results show that calcineurin is a target of drug-immunophilin complexes in vivo and establish a physiological role for calcineurin in T-cell activation.[3]

C44H69NO12

804.0182

803.481

C, 57.92; H, 5.69; Cl, 3.64; F, 5.85; N, 7.19; O, 9.85; S, 9.87

104987-11-3

Tacrolimus monohydrate;109581-93-3;Tacrolimus-13C,d2;1356841-89-8

445643

White to off-white solid powder

1.2±0.1 g/cm3

871.7±75.0 °C at 760 mmHg

113-115°C

481.0±37.1 °C

0.0±0.6 mmHg at 25°C

1.549

fungus Streptomyces tsukubaensis.

3.96

178.36

3

12

7

57

1480

14

O1[C@]2(C(C(N3C([H])([H])C([H])([H])C([H])([H])C([H])([H])[C@@]3([H])C(=O)O[C@]([H])(/C(/C([H])([H])[H])=C(\[H])/[C@]3([H])C([H])([H])C([H])([H])[C@]([H])([C@@]([H])(C3([H])[H])OC([H])([H])[H])O[H])[C@]([H])(C([H])([H])[H])[C@]([H])(C([H])([H])C([C@]([H])(C([H])([H])C([H])=C([H])[H])C([H])=C(C([H])([H])[H])C([H])([H])[C@]([H])(C([H])([H])[H])C([H])([H])[C@@]([H])([C@]1([H])[C@]([H])(C([H])([H])[C@@]2([H])C([H])([H])[H])OC([H])([H])[H])OC([H])([H])[H])=O)O[H])=O)=O)O[H] |c:78|

QJJXYPPXXYFBGM-LFZNUXCKSA-N

InChI=1S/C44H69NO12/c1-10-13-31-19-25(2)18-26(3)20-37(54-8)40-38(55-9)22-28(5)44(52,57-40)41(49)42(50)45-17-12-11-14-32(45)43(51)56-39(29(6)34(47)24-35(31)48)27(4)21-30-15-16-33(46)36(23-30)53-7/h10,19,21,26,28-34,36-40,46-47,52H,1,11-18,20,22-24H2,2-9H3/b25-19+,27-21+/t26-,28+,29+,30-,31+,32-,33+,34-,36+,37-,38-,39+,40+,44+/m0/s1

(1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,25S,27R)-1,14-dihydroxy-12-[(E)-1-[(1R,3R,4R)-4-hydroxy-3-methoxycyclohexyl]prop-1-en-2-yl]-23,25-dimethoxy-13,19,21,27-tetramethyl-17-prop-2-enyl-11,28-dioxa-4-azatricyclo[22.3.1.04,9]octacos-18-ene-2,3,10,16-tetrone

FR900506;FR 900506; FR-900506; FK 506; FK-506; FK506; fujimycin; Prograf; Protopic; Advagraf; Astagraf XL; Fujimycin; 104987-11-3; Prograf; Tsukubaenolide; Tacrolimus anhydrous; Protopic; Anhydrous Tacrolimus;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

注意： 本产品在运输和储存过程中需避光。

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: ~94 mg/mL (~116.9 mM)
Water: <1 mg/mL
Ethanol: ~83 mg/mL (~103.2 mM)

配方 1 中的溶解度: 2.75 mg/mL (3.42 mM) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (这些助溶剂从左到右依次添加，逐一添加), 悬浮液；超声助溶。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: ≥ 2.5 mg/mL (3.11 mM) (饱和度未知) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL澄清DMSO储备液加入到400 μL PEG300中，混匀；然后向上述溶液中加入50 μL Tween-80，混匀；加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 3 中的溶解度: 2.5 mg/mL (3.11 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 悬浊液; 超声助溶。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL澄清DMSO储备液加入900 μL 20% SBE-β-CD生理盐水溶液中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 4 中的溶解度: ≥ 2.5 mg/mL (3.11 mM) (饱和度未知) in 10% DMSO + 90% Corn Oil (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，你可以将100 μL 25.0 mg/mL澄清的DMSO储备液加入到900 μL玉米油中，混合均匀。

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配方 5 中的溶解度： 5% DMSO+玉米油： 15mg/mL

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
5、为保证最佳实验结果，工作液请现配现用！
6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。