Antisense TGF-beta2 immunotherapy for hepatocellular carcinoma: treatment in a rat tumor model

BACKGROUND

The overexpression of transforming growth factor-beta (TGF-beta) in hepatocellular carcinoma (HCC) appears to induce immunosuppression toward the tumor cells.

METHODS

A rat HCC cell line, Morris hepatoma rat cell line (MRH)-7777 (MRH), was transfected with antisense TGF-beta2 in pCEP-4 vector and used as immunotherapy against the development of wild-type tumors. An enzyme-linked immunosorbent assay (ELISA) confirmed that TGF-beta2 production was markedly lower for antisense modified cells as compared to wild-type tumor cells. Tumors were initiated by injecting MRH cells into the flanks of Buffalo rats. This was followed by biweekly vaccinations with irradiated MRH cells (unmodified, pCEP-4 alone, or antisense TGF-beta2 modified).

RESULTS

In the group that received irradiated MRH unmodified cells, 55% of rats died from tumor burden, and 36% developed tumor regression. In the group that received irradiated MRH cells modified with pCEP-4 vector alone, 50% died from tumors and 33% had spontaneous regression. In animals treated with pCEP-4/TGF-beta antisense modified cells, none developed tumors. Cell-mediated cytotoxicity assays demonstrated a twofold increase in lytic activity in the effector cells of the animals treated with antisense modified cells.

CONCLUSIONS

These results demonstrate the successful treatment of HCC tumors in rats by a HCC vaccine genetically altered with antisense TGF-beta2. Decreased production of TGF-beta in HCC vaccine enhances immunogenicity against wild-type HCC tumor cells.

Rational manipulation of oxygen delivery

BACKGROUND

Optimization of oxygen delivery remains the best method to prevent and the only way to treat common intensive care unit syndromes such as sepsis, multiple organ dysfunction, and acute lung injury. This paper reviews the elements of oxygen delivery, describes how clinical interventions work through those elements to alter oxygen delivery, reviews theoretical and empirical data relating to manipulation of each element, and distinguishes between therapeutic means and clinical endpoints in the care of the critically ill.

MATERIALS AND METHODS

Recent literature is reviewed. Relevant equations are detailed. Computer models and patient data illustrate key points.

RESULTS

Clinical interventions intended to improve oxygen delivery all work through at least one of seven variables (oxygen saturation, hemoglobin concentration, heart rate, mean arterial blood pressure, systemic vascular resistance, end-diastolic volume, and ejection fraction). Because interventions that increase oxygen delivery are always accompanied by physiologic costs, cavalier application of any therapy in the intensive care unit may actually decrease oxygen delivery, harming the critically ill patient. Various clinical indicators may be used as endpoints to guide therapy.

CONCLUSIONS

While a systematic consideration of the elements of oxygen delivery reveals weaknesses in experimental evidence guiding optimal treatment of shock, reasonable strategies as well as avoidable pitfalls emerge from the data. Furthermore, facility with each of the elements of oxygen delivery makes ICU management easier to teach and to apply.

Irradiation-induced up-regulation of Fas in esophageal squamous cell carcinoma is not accompanied by Fas ligand-mediated apoptosis

BACKGROUND AND OBJECTIVES

Fas (APO-1) induces apoptosis after binding Fas ligand (FasL). Evidence suggests that tumors may use this interaction to evade the host immune response. Fas/FasL expression has not been reported in esophageal cancer. We hypothesized that Fas expression would render esophageal cancer cells susceptible to Fas ligation and that irradiation of the cells would increase Fas expression.

METHODS

Two human esophageal squamous cell carcinoma lines, KYSE 150, which has a wild-type (wt) p53 gene, and 410 (mutated p53), were irradiated. Reverse-transcriptase polymerase chain reaction was used to detect Fas and FasL expression. Fas protein was quantitated by enzyme-linked immunosorbent assay and its presence further confirmed by Western analysis. FasL was detected by Western analysis. Cells were treated with Fas monoclonal antibody (maximum 0.05 microg/ml)+/-cycloheximide, and viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cells were also transduced with FasL cDNA and then quantified.

RESULTS

Both lines expressed Fas and FasL, but only the KYSE 150 cell line displayed an increase in Fas following irradiation. No alteration in cell growth was detected for Fas antibody- or FasL-transduced groups versus controls.

CONCLUSIONS

We have demonstrated Fas and FasL expression in esophageal tumor lines. We have also shown that Fas levels are significantly increased in response to irradiation in a wt p53 line. However, cells were resistant to treatment with Fas antibody or following transduction with FasL, suggesting that these tumor cells may use Fas/FasL expression to evade the host immune response.

Long-term results of pediatric liver transplantation: an analysis of 569 transplants

OBJECTIVE

To analyze a single center's 13-year experience with 569 pediatric orthotopic liver transplants for end-stage liver disease.

SUMMARY BACKGROUND DATA

Despite advances in medical therapy, liver replacement continues to be the only definitive mode of therapy for children with end-stage liver disease. Innovative surgical techniques and improved immunosuppression have broadened the application of liver replacement for affected children. However, liver transplantation in the child remains challenging because of the scarcity of donor organs, complex surgical technical demands, and the necessity to prevent long-term complications.

METHODS

The medical records of 440 consecutive patients younger than 18 years of age undergoing orthotopic liver transplantation for end-stage liver disease from March 20, 1984, to November 15, 1997, were reviewed. Results were analyzed using Cox multivariate regression analysis to determine the statistical strength of independent associations between pretransplant covariates and patient and graft survival. Actuarial patient and graft survival rates were determined at 1, 3, 5, and 10 years. The type and incidence of posttransplant complications were determined, as was the quality of long-term allograft function. The median follow-up period was 4.1 years.

RESULTS

Biliary atresia was the most common cause (50.4%) of endstage liver disease in this patient population. The median recipient age was 2.4 years; 239 patients (54%) were younger than 3 years of age and 1 11 patients (25%) were younger than 1 year of age. There were 471 whole organs, 29 were ex vivo reduced size, 33 were living-related donor, and 36 were in situ split-liver allografts. Three hundred forty-three (78%) patients underwent a single allograft, whereas 97 patients required retransplantation; hepatic artery thrombosis was the most common indication for retransplantation (55 patients). The 1-, 3-, 5-, and 10-year actuarial patient survival rates were 82%, 80%, 78%, and 76%, respectively; allograft survival rates were 68%, 63%, 60%, and 54%. Long-term liver function remains excellent: current median follow-up values for total bilirubin and aspartate aminotransferase were 0.5 mg/dl and 54 IU/L, respectively. Cox multivariate regression analysis demonstrated that pretransplant patient age, the era of transplantation, and the number of allografts performed significantly and independently predicted patient survival rates, whereas allograft type and pretransplant diagnosis did not.

CONCLUSIONS

Liver transplantation in the pediatric patient is a durable procedure that provides excellent long-term survival. Although there have been overall improvements in patient outcome with increased experience, the effect is most pronounced for patients younger than 1 year of age. Retransplantation, although effective in a meaningful number of patients, continues to carry a progressive decrement in survival with the number of allografts performed. Use of living-related and in situ split-liver allografts has dramatically reduced waiting times for small children and has improved patient survival.

Liver transplantation for adult polycystic liver disease

Polycystic liver disease, commonly associated with polycystic kidney disease, can result in massive hepatomegaly and debilitating symptoms. Surgical intervention for symptomatic polycystic liver disease has been associated with significant morbidity and inconsistent long-term palliation; it is more appropriate in patients with a single dominant cyst or cysts which is/are confined to one lobe. At our institution, nine patients have undergone orthotopic liver transplantation for symptomatic hepatic cysts with excellent long-term results and minimal morbidity and mortality. Surgical candidates were selected based on severe limitations in daily activities and on sequelae of hepatic cystic involvement. Other factors considered were the extent and pattern of hepatic cystic disease, the degree of hepatic and renal dysfunction, and prior surgical intervention. Three patients (33%) required combined liver and kidney transplantation because of renal cystic involvement with renal insufficiency. The one-year survival rate was 89% with excellent symptomatic relief and improved quality of life in all the surviving patients. One death occurred in a significantly malnourished 62-year-old female. Complications included one case each of hepatic artery thrombosis requiring retransplantation, biliary leak necessitating biliary reconstruction, and postoperative bleeding requiring re-exploration. The mean hospital stay was 23 days and the mean intraoperative blood transfusion requirement was 18 units. Our experience demonstrates that appropriately selected patients with extensive hepatic involvement with adult polycystic liver disease can have an excellent outcome with transplantation, with morbidity comparable with other surgical options.

Liver transplantation for fulminant hepatic failure in the pediatric patient

OBJECTIVE

To review the clinical characteristics, outcomes, and risk factors for survival among 57 pediatric patients undergoing orthotopic liver transplantation for fulminant hepatic failure at the University of California, Los Angeles, Center for the Health Sciences.

DESIGN

The medical records of 57 consecutive pediatric patients undergoing orthotopic liver transplantation for fulminant hepatic failure from July 1, 1984, to June 25, 1997, were reviewed and survival data were analyzed via univariate and multivariate statistical methods. The type and incidence of posttransplant complications were determined as was the quality of long-term graft function. Median follow-up period was 3.38 years (range, 0-10.02 years).

RESULTS

The 1-, 3-, and 5-year actuarial patient survival rates were 77%, 77%, and 77%, respectively, while graft survivals were 73%, 65%, and 65%. Stepwise Cox regression analysis revealed that recipient age and ventilator dependency at the time of transplantation were independently and significantly correlated with patient survival, whereas no association was found between survival and grade of encephalopathy, prior abdominal surgery, recipient weight, pretransplantation values for total bilirubin or prothrombin time, ABO match, allograft type, peak posttransplantation aspartate aminotransferase levels, or the presence of posttransplantation hepatic artery thrombosis. Non-ventilator-dependent patients demonstrated a 96% 1-, 3-, and 5-year survival as compared with only 56% at these same time points for those children requiring ventilator support at the time of transplantation (P < .001). At the time of most recent follow-up, median values for total bilirubin and aspartate aminotransferase concentrations were 10.3 micromol/L (0.6 mg/dL) and 56 U/L, respectively, in the 40 surviving patients.

CONCLUSIONS

In children undergoing liver transplantation for fulminant hepatic failure: (1) overall results are comparable to those achieved for less emergent non-neoplastic indications in this same age group; (2) ventilator dependency prior to transplantation is the strongest predictor of ultimate survival, followed by recipient age; (3) 5-year survival exceeds 90% in recipients who are ventilator independent immediately prior to liver transplantation but is significantly compromised once the need for mechanical ventilation supervenes, particularly in those younger than 4 years; and (4) prompt referral and timely liver replacement are the cornerstones of optimal outcome.

Pravastatin increases survival and inhibits natural killer cell enhancement factor in liver transplanted rats

Pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has been shown to decrease the number of acute rejection episodes in cardiac and renal transplant patients. This study evaluates the effects of pravastatin on survival of rats following liver transplant and attempts to elucidate the mechanisms of these effects. Both survival and natural killer cell enhancing factor (NKEF) studies utilized Dark Agouti rats for donor livers transplanted into Brown Norway rats as recipients. All rats received daily low-dose cyclosporine (CsA) 2 mg/kg/day by gavage. The treated groups also received gavage doses of pravastatin, 20 mg/kg/day. Survival data were analyzed by the method of Kaplan-Meier and log-rank chi 2 tests for statistical significance. For NKEF evaluation, rats were sacrificed at varying time points; total RNA was extracted from the liver and hybridized with 32P-radiolabeled NKEF DNA probes in the Northern blot technique. Radiographs were quantitated using densitometry. Data were analyzed by two-way ANOVA. Actuarial survival was improved (P < < 0.05) in rats treated with pravastatin in addition to low-dose CsA (n = 41, CsA alone n = 74). Less fibrosis and chronic rejection was seen on histological section in the treated animal livers, P < 0.05, NKEF was seen maximally at Days 5-15 tapering off at Day 21. NKEF-a and NKEF-b levels were significantly decreased in the animals treated with CsA and pravastatin compared to CsA alone in the group of animals < 16 days postop (P < < 0.05). Pravastatin improves survival in rats following OLT and while the mechanism is still unknown, inhibition of natural killer cell enhancement factor may represent an alteration in the overall immune response.

K-ras status does not predict successful hepatic resection of colorectal cancer metastasis

OBJECTIVE

To establish whether specific K-ras alterations are predictive of less aggressive tumor behavior and subsequently those patients who are most likely to benefit from resection of hepatic metastases from colorectal carcinoma.

DESIGN

Evaluation of long-term survivors of hepatic resection for metastases of colorectal carcinoma (median survival, 85 months).

RESULTS

DNA, extracted from 26 paraffin-embedded hepatic metastases from 19 patients, was analyzed using single-strand conformation polymorphism and direct sequence analysis of codons 12 and 13 of the K-ras gene. Seven of 19 patients were found to harbor K-ras mutations. A similar frequency and spectrum of K-ras mutational events was detected in 14 patients with short-term survival following pathologic diagnosis of hepatic metastasis.

CONCLUSIONS

Neither the presence of a K-ras mutational event nor the precise nucleotide change are predictive of less aggressive tumor behavior, and genetic alterations at this locus alone cannot be used to select patients undergoing resection of hepatic metastases from colorectal carcinoma.