Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein purification and molecular cloning have defined five classes of protein serine-threonine phosphatase catalytic subunits referred to as types 1, 2A, 2B (calcineurin), 2C, and X. Protein serine-threonine phosphatases 1, 2A, 2B, and X appear to have significant sequence homologies, whereas the 2C enzyme is more divergent. We have used the polymerase chain reaction to define the multiplicity of the closely related types 1, 2A, 2B, and X phosphatase catalytic subunits in two clonal cell lines, rat PC12 pheochromocytoma and rat FTO-2B hepatoma. RNAs for all four related phosphatase types were expressed in both cell lines. In addition to the phosphatase X enzyme, four phosphatase 1, two phosphatase 2A, and three phosphatase 2B isoforms were identified in PC12 and FTO-2B cells. The results indicate a large multiplicity of protein serine-threonine phosphatases within clonal cells of different tissue origin, suggesting that their role in cell regulation will be as divergent as that for the protein serine-threonine kinases.
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PMID:Multiplicity of protein serine-threonine phosphatases in PC12 pheochromocytoma and FTO-2B hepatoma cells. 217 76

Cyclosporin (CsA) inhibits mitochondrial death signaling and opposes tumor necrosis factor (TNF)-induced apoptosis in vitro. However, CsA is also a potent inhibitor of calcineurin, a phosphatase that may participate in cell death. Therefore, we tested the hypothesis that calcineurin regulates TNF cytotoxicity in rat hepatoma cells (FTO2B). TNF-treated FTO2B cells appeared apoptotic by DNA fragmentation, nuclear condensation, annexin V binding, and caspase activation. We studied two calcineurin inhibitors, CsA and FK506, and found that each potently inhibited TNF cytotoxicity. Western blot demonstrated calcineurin in FTO2B homogenates. In a model of mitochondrial permeability transition (MPT), we found that CsA prevented MPT and cytochrome c release, while FK506 inhibited neither. In summary, we present evidence that calcineurin participates in an apoptotic death pathway activated by TNF. CsA may oppose programmed cell death by inhibiting calcineurin activity and/or inhibiting mitochondrial signaling.
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PMID:Regulation of tumor necrosis factor cytotoxicity by calcineurin. 1104 65

An increasing number of patients with hepatocellular carcinoma (HCC) are undergoing evaluation for listing for liver transplantation. Criteria for selection require ongoing review for suitability. A consecutive series of 40 patients with HCC within the standard Milan criteria (single tumors n = 19 < 5 cm, or up to 3 tumors < 3 cm) and beyond (Extended Criteria; single tumors n = 21 < 7.5 cm, multiple tumors < 5 cm) underwent liver transplant with a sirolimus-based immunosuppressive protocol designed to minimize exposure to calcineurin inhibitors and steroids. At 44.3 +/- 19.3 months (mean +/- standard deviation) follow-up, 1- and 4-year survivals (Kaplan-Meier) are 94.1 +/- 5.7% and 87.4 +/- 9.3%, in the Milan group, respectively, and 90.5 +/- 6.4% and 82.9 +/- 9.3% in the Extended Criteria group, respectively. Five patients died during follow-up, only 1 from recurrent HCC. Five tumor recurrences have occurred at median 17 (mean 22 +/- 17) months posttransplant, 1 in the Milan group and 4 in the Extended Criteria group. Median survival in the patients with recurrent tumor is 42 months (mean 45 +/- 25), and the median postrecurrence survival is 15.5 months (mean 23 +/- 16). The rate of patients who were alive and free of tumor at 1 and 4 years is 94.1 +/- 5.7% and 81.1 +/- 9.9%, respectively, in the Milan group and is 90.5 +/- 6.4% and 76.8 +/- 10.5%, respectively, in the Extended Criteria group. Five patients had sirolimus discontinued for toxicity, while 24 of 35 surviving patients have sirolimus monotherapy immunosuppression. In conclusion, the Milan criteria for liver transplantation in the presence of HCC can be carefully extended without compromising outcomes. This sirolimus based immunosuppression protocol appears to have beneficial effects on tumor recurrence and survival with an acceptable rate of rejection and toxicity.
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PMID:Sirolimus-based immunosuppression for liver transplantation in the presence of extended criteria for hepatocellular carcinoma. 1537 37

Hepatitis C virus (HCV) recurs in nearly all patients after liver transplantation. This recurrence is associated with progressive fibrosis and graft loss. It remains unclear whether the natural course of HCV recurrence is altered in patients who undergo living donor liver transplantation (LDLT). We conducted a prospective, controlled trial using protocol liver biopsies to evaluate the histologic outcome of recurrent HCV in 23 patients who underwent LDLT and 53 patients who underwent transplantation with a deceased donor liver (DDLT) during the same period of time. Patients who did not survive at least 6 months after transplantation or who had hepatocellular carcinoma or any other coexistent liver disease were excluded from analysis. All patients underwent protocol liver biopsy at 6 months and at 12 months and at yearly intervals thereafter. The mean age, sex, racial distribution, and serum HCV RNA and the percentage of patients with genotype 1 were similar in the 2 groups of patients. The model for end-stage liver disease score at the time of transplantation was slightly lower in patients who underwent LDLT, but this difference was not significant. The distribution of immunosuppression agents used, the mean doses of calcineurin agents, the use of mycophenolate mofetil, and the dose and tapering schedule for prednisone were similar in both groups of patients. The mean duration of follow-up was 40 months. No significant difference in either graft or patient survival or the percentage of patients who developed acute rejection was noted in the 2 groups of patients. At 48 months, graft and patient survival were 82% and 82% and 75% and 79% for patients who underwent DDLT and LDLT, respectively. The degree of hepatic inflammation increased stepwise over 3 years but was not significantly different in the 2 patient groups. In contrast, the mean fibrosis score and the percentage of patients with fibrosis increased stepwise after DDLT but appeared to plateau 12 months after LDLT. At 36 months, fibrosis was present in 78% of DDLT patients, and mean fibrosis score was 1.9, compared with 59% with fibrosis and a mean score of.9 after LDLT. In conclusion, these data strongly suggest that fibrosis progression from recurrent HCV is not more severe in patients after LDLT.
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PMID:Histologic recurrence of chronic hepatitis C virus in patients after living donor and deceased donor liver transplantation. 1537 36

Calcineurin has been proposed to regulate skeletal muscle hypertrophy, while its relevance to the pathogenesis of muscle atrophy is unknown. The present study was aimed to investigate if perturbations of the calcineurin pathway may be involved in causing skeletal muscle atrophy in two different experimental conditions: cancer cachexia (rats bearing the AH-130 hepatoma), and hyperglycemia (rats treated with streptozotocin). Calcineurin expression in the gastrocnemius was comparable between tumor hosts and controls. By contrast, besides unchanged calcineurin mRNA levels, those of protein were lower in diabetic animals than in controls. The DNA-binding activity of the transcription factors NF-AT and MEF-2 was analysed as an indirect measure of calcineurin activity in vivo. The nuclear translocation of both factors was similar in tumor hosts and controls. Consistently with the reduced calcineurin protein levels, NF-AT DNA-binding activity significantly decreased in the gastrocnemius of diabetic rats compared to controls. Finally, muscle wasting correction afforded in the AH-130 hosts by pentoxifylline or interleukin-15 was not paralleled by changes of calcineurin mRNA levels, while treatment of diabetic animals with dehydroepiandrosterone partially prevented calcineurin down-regulation. These results suggest that modulations of calcineurin activity may be involved in the pathogenesis of muscle wasting in diabetes though not in cancer cachexia.
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PMID:Modulations of the calcineurin/NF-AT pathway in skeletal muscle atrophy. 1744 96

Experience with sirolimus (SRL)-based immunosuppression following orthotopic liver transplantation (OLT) is rapidly accumulating. In combination with calcineurin inhibitors (CNIs), SRL may reduce the incidence of acute rejection and lower overall required drug levels. This study sought to quantify long-term outcome following OLT in patients with cirrhosis and concomitant hepatocellular carcinoma (HCC) who were treated with an SRL-based regimen as a primary therapy. From January 2000 to June 2007, 97 patients underwent OLT for end-stage liver disease and HCC at the University of Colorado Health Sciences Center. Of those, 45 patients received SRL, in addition to CNIs, as a component of their primary immunosuppression regimen post-OLT. Conversely, 52 patients received the standard immunosuppression regimen including CNIs, mycophenolate mofetil, and corticosteroids. The 2 treatment groups were compared with respect to the following variables: age, gender, tumor stage by explant, grade, size, presence of vascular invasion, focality, Child's class, baseline creatinine, and warm and cold ischemic times. The 2 groups were comparable by all factors save for cold ischemic time, which was significantly longer in the CNI-treated group. Overall survival at 1 and 5 years post-OLT for patients treated with SRL was 95.5% and 78.8%, respectively. Conversely, survival in patients treated with CNIs exclusively at the same time intervals was 83% and 62%. Although there was no difference in the incidence of major complications, the SRL group experienced a modest improvement in renal function. Cumulatively, these data suggest a potential survival benefit with SRL-based therapy in patients undergoing OLT for end-stage liver disease and concomitant malignancy.
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PMID:Sirolimus-based immunosuppression following liver transplantation for hepatocellular carcinoma. 1832 56

Sirolimus (SRL) is an mTOR inhibitor that has been shown, in contrast to calcineurin inhibitors (CNI), to inhibit cancers in experimental models. Since February 2005, we introduced SRL in liver transplant patients in group a, in whom the primary disease was hepatocellular carcinoma (HCC) associated with hepatitis B virus (HBV), hepatitis C virus (HCV), alcoholic or autoimmune liver cirrhosis, and group b, HCC-negative patients who developed posttransplantation cancers de novo. Of 18 patients in group a, 11 received SRL ab initio (subgroup a1), starting for 10 patients at 66.1+/-29.2 days after surgical healing and after 10 days in 1 case; the remaining 7 patients (subgroup a2) received SRL at 31.2+/-24.2 months. Three patients in group b, included 1 with Kaposi's sarcoma, 1 with bladder cancer, and 1 with thyroid cancer. In this group, SRL was introduced at 80.8+/-40.4 months. In all patients but one, who received a single 5 mg loading dose, SRL was started at 2 mg/d and adjusted to 6 to 8 ng/mL blood levels. CNI drugs, present as primary therapy, were gradually tapered to low levels and eventually stopped. The following observations were drawn from this initial experience: (1) 4/21 (19.0%) patients had to discontinue SRL because of early and late side effects: thrombocytopenia (n=2) and headache with leukopenia and leg edema associated with knee joint arthralgia (n=2); (2) 14 patients (11 in group a and 3 in group b) are still on SRL monotherapy; (3) 1 HCC recurrence and 1 de novo pancreatic adenocarcinoma were observed at 14 and 16 months, respectively (at the time of transplantation, both patients were beyond the MIlan HCC criteria), and (4) 1 patient, from subgroup a1, died after 99 days due to pneumonitis and possible relation to SRL lung toxicity. In conclusion, SRL appeared to be an effective immunosuppressant that could be used as monotherapy in liver transplant patients. Any conclusion on SRL anticancer effects can only come from randomized large studies after long follow-up.
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PMID:Sirolimus therapy in liver transplant patients: an initial experience at a single center. 1867 98

CHP2 (calcineurin B homologous protein 2) was initially identified as a tumor-associated antigen highly expressed in hepatocellular carcinoma. Its biological function remains largely unknown except for a potential role in transmembrane Na(+)/H(+) exchange. In the present study, we observed that ectopic expression of CHP2 promoted the proliferation of HEK293 cells, whereas knockdown of endogenous CHP2 expression in HepG2 inhibited cell proliferation. When inoculated into nude mice, CHP2 transfected HEK293 cells displayed markedly increased oncogenic potential. In analysis of the underlying molecular mechanisms, we found that like calcineurin B, CHP2 was able to bind to and stimulate the phosphatase activity of calcineurin A. In accord with this, CHP2-transfected cells showed increased nuclear presence of NFATc3 (nuclear factor of activated T cells) and enhanced NFAT activity. Finally, both accelerated cell proliferation and NFAT activation following CHP2 transfection could be suppressed by the calcineurin inhibitor cyclosporine A, suggesting an intrinsic connection between these events. Taken together, our results highlighted a potential role of CHP2 in tumorigenesis and revealed a novel function of CHP2 as an activator of the calcineurin/NFAT signaling pathway.
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PMID:CHP2 activates the calcineurin/nuclear factor of activated T cells signaling pathway and enhances the oncogenic potential of HEK293 cells. 1881 28

mTOR is a central regulator of cell growth and angiogenesis. The mTOR pathway is activated in 40-50% of patients with hepatocellular cancer (HCC). In different models (i.e., hepatoma cell lines and implanted HCC tumors in rats), mTOR inhibitors (mTORIs) were effective in reducing cell growth and tumor vascularity. Synergistic effects were observed for mTORIs and chemotherapeutic agents in these studies, while other combinations involving mTORIs and inhibitors of growth hormones and angiogenesis are awaiting further clinical testing. A number of mTORIs are already clinically available (e.g., sirolimus, temsirolimus and everolimus), sharing similiar pharmacokinetic parameters (except for absorption) and side effects. Clinical data are, as yet, only preliminary and are mainly derived from retrospective studies in patients who underwent liver transplantation for HCC. Those patients had received sirolimus thereafter for immunosuppression, and a much lower rate of tumor recurrence than with calcineurin inhibitors alone was noted. Current prospective trials for treatment of advanced HCC include mTORIs alone or in combination with either transarterial chemoembolization or other systemic drugs, and will be discussed in detail in this review.
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PMID:mTOR inhibitors for hepatocellular cancer: a forward-moving target. 1919 62

Sirolimus (SRL) is a newer immunosuppressant whose possible benefits and side effects in comparison to calcineurin inhibitors (CNIs) still have to be addressed in the liver transplantation setting. We report the results of the use of SRL in 86 liver transplant recipients, 38 of whom received SRL as the main immunosuppressant in a CNI-sparing regimen. Indications for the use of SRL were: impaired renal function (n = 32), CNI neurotoxicity (n = 16), hepatocellular carcinoma (HCC) at high risk of recurrence (n = 21), recurrence of HCC (n = 6), de novo malignancies (n = 4), cholangiocarcinoma (n = 1), and the need to reinforce immunosuppression (n = 6). Among patients on SRL-based treatment, four episodes of acute rejection were observed, three of which occurred during the first postoperative month. Renal function significantly improved when sirolimus was introduced within the third postoperative month, while no change was observed when it was introduced later. Neurological symptoms resolved completely in 14/16 patients. The 3-year recurrence-free survival of patients with HCC on SRL was 84%. Sixty-two patients developed side effects that required drug withdrawal in seven cases. There was a reduced prevalence of hypertension and new-onset diabetes among patients under SRL. In conclusion, SRL was an effective immunosuppressant even when used in a CNI-sparing regimen. It was beneficial for patients with recently developed renal dysfunction or neurological disorders.
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PMID:Sirolimus in liver transplant recipients: a large single-center experience. 2083 48


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