Colorectal cancer cell adhesion attenuates Ad-E2F-1 mediated apoptosis

BACKGROUND: The complex interplay of cell adhesion molecules, intracellular signaling, and tumor growth behavior have important implications for the failure of most conventional cancer therapies. Cell adhesion to the basement membrane has been shown to promote tumor cell survival. We hypothesize that the presence of matrix substrate contributes to chemoresistance through signaling via cell adhesion molecule. MATERIALS AND METHODS: RKO colorectal cancer cells express integrin beta1 to adhere to substrate. We measured apoptosis of the cells after infection with adenovirus vector containing the transgene E2F-1 (Ad-E2F-1), a potent tumor suppressor gene, and Ad-LacZ (as control), both under the control of the cytomegalovirus promoter. Cells were plated on Matrigel, an extracellular substrate similar to basement membrane and compared to tissue culture plastic. Apoptosis was assessed by flow cytometry-based TUNEL assay and cell proliferation was assessed by WST-1 assay. E2F-1 expression was confirmed by Western blot analysis. A function-blocking anti-beta1 integrin antibody was used to assess the contribution of beta1 on cell survival. RESULTS: At 120 h postinfection of RKO cells with 50 multiplicity of infection, cells plated on plastic underwent marked apoptosis in response to Ad-E2F-1 compared with Ad-LacZ control-treated cells (53% vs 1% apoptosis, respectively). However, when cells were plated on Matrigel, the same dose of E2F-1 was ineffective at inducing apoptosis (3% vs 1% apoptosis, comparing Ad-E2F-1 with Ad-LacZ control). The cell proliferation assay showed >3-fold cell survival in E2F-1-infected cells on Matrigel vs plastic (P < 0.004). By Western blot analysis, attenuation of apoptosis may be a result of reduction in transduction efficiency on Matrigel and function-blocking anti-beta1 integrin antibody does not abolish the decrease in apoptosis afforded by Matrigel. CONCLUSIONS: These data suggest that escape from adenoviral E2F-1-mediated apoptosis, at least in part, is related to reduction of intracellular E2F-1 expression. Interactions involving cellular adhesion via beta1 integrin to matrix proteins does not seem to contribute toward gene therapy resistance. Further studies will investigate other specific receptor-ligand interactions after gene and/or chemotherapy.     

Effectiveness and safety of mycophenolate mofetil as monotherapy in liver transplantation

INTRODUCTION: Calcineurin inhibitors (CIs) cause substantial long-term morbidity and mortality among orthotopic liver transplantation (OLT) patients. Our aim was to evaluate the effectiveness and safety of mycophenolate mofetil (MMF) among OLT patients with CI-related side effects. PATIENTS: Thirty three adult patients, including 29 men and 4 women of mean age 57 years, underwent OLT between 1986 and 2000 under treatment with CIs (28 cyclosporine and five tacrolimus). Mean follow-up after OLT was 59 months. Adverse effects were renal dysfunction in 26, hypertension in 23, and neurotoxicity in two. MMF was added gradually while simultaneously reducing the dosage of CI. RESULTS: After a mean 15-months follow-up of MMF treatment, CIs had been withdrawn in 28 patients (85%). The mean time from the initiation of MMF and CI withdrawal was 5 months. During the first year of follow-up chronic renal dysfunction improved in 16 of 26 patients (61.6%) accompanied by a decreased serum creatinine and urea and an increase in creatinine clearance. Among 13/23 (56.5%) hypertensive patients, there was a significant decrease in blood pressure or the number of antihypertensive drugs (P<.05). One patient with neurotoxicity improved. Twenty-two patients (66%) displayed adverse events: five rejections (15%) including four acute episodes, controlled by CI re-introduction, and one chronic reaction. The most frequent adverse effects were herpes simplex infection in 10 patients (30%), asthenia in nine (27%), diarrhea in five (15%) and thrombocytopenia in four (12%). Nevertheless, only six patients (19%) required MMF dose reduction, namely, three patients with GI intolerance, two with repeated VHS infections, and one with anemia. CONCLUSIONS: MMF monotherapy improves renal function and blood pressure levels in more than 50% of patients with chronic renal impairment and hypertension after OLT. Many of the side effects of MMF were mild; it was safe accompanied by a low incidence of rejection reactions.     

Osteopenia in children who have undergone posterior fossa or craniospinal irradiation for brain tumors

OBJECTIVES: To determine lumbar spine and total body bone mineral density (BMD) in pediatric patients who have undergone cranial or craniospinal irradiation for posterior fossa tumors, specifically medulloblastoma and ependymoma and to analyze the association between degree of osteopenia and factors that may affect BMD. METHODS: Retrospective and prospective data collection included medical record review and examination, including pubertal, dietary, and activity assessment. Lumbar spine and total body BMD were measured by means of dual energy x-ray absorptiometry. Patients were routinely observed by the endocrinology department, and hormone deficiencies were corrected promptly. A subset of patients received calcium and vitamin D supplementation and underwent repeat BMD measurement 1 year later. RESULTS: Of 24 patients aged 4 to 20 years, 11 of whom were male, recruited from 1996 through 1999, 19 had medulloblastoma. All 19 underwent craniospinal radiotherapy plus a boost to the posterior fossa (mean +/- SD of 5410 +/- 130 rad [54.1 +/- 1.3 Gy] to the posterior fossa, mean +/- SD of 3470 +/- 460 rad [34.7 +/- 4.6 Gy] to the whole brain and spinal axis), and 8 of 19 underwent chemotherapy. The remaining 5 patients had ependymoma and underwent irradiation to the posterior fossa only (mean +/- SD of 5680 +/- 720 rad [56.8 +/- 7.2 Gy]). Therefore, there were 3 treatment groups: craniospinal irradiation and chemotherapy, only craniospinal irradiation, and only posterior fossa irradiation. Bone mineral studies were performed a mean +/- SD of 5.42 +/- 3.23 years after therapy. Our patients had lower total body BMD (mean z score, -0.47; 95% confidence interval, -0.85 to -0.09) and lumbar spine BMD (mean z score, -1.27; 95% confidence interval, -1.81 to -0.73) as compared with those of the the general population. There was no significant difference in mean lumbar spine BMD between patients in the 3 groups. Our patients consumed a diet deficient in vitamin D and calcium (mean +/- SD 53.6% +/- 24.1% and 70.0% +/- 37.4% of the amount recommended, respectively). Of 7 patients who underwent measurements 1 year later, 5 had in increase in BMD that was parallel to normal curves, with no compensatory increase. Four patients were hypothyroid, 6 were growth hormone deficient, and 6 were both. All hormones were replaced, with the exception of growth hormone in 1 patient. By using regression analysis, the factors that affected lumbar spine BMD, protectively in both cases, were calcium intake (beta = 0.015, 95% confidence interval, 0.001-0.029) and female sex (beta = 1.422, 95% confidence interval, 0.456-2.388). CONCLUSIONS: Children who have undergone irradiation for posterior fossa tumors have diminished total body and lumbar spine BMD, as compared with those of the general population. This reduction was similar within all 3 treatment groups, which suggests that chemotherapy did not play a major role and that localized irradiation may have systemic effects. This population often has balance and gait problems, so the risk of falling, coupled with osteopenia, may place them at considerably increased risk of fractures.     

Hepatic allograft arterialization by means of the gastroduodenal bifurcation (branch patch) as a prognostic factor

INTRODUCTION: Because of the current shortage of cadaveric organs, it is important to determine preoperatively those variables that are readily available, inexpensive, and noninvasive that can predict a higher incidence of hepatic artery thrombosis (HAT). MATERIAL AND METHODS: From April 1986 to October 2001, 717 patients underwent 804 liver transplants. All the arterial reconstructions were performed with fine (7-0) monofilament sutures in an interrupted fashion. Two methods were used: group I, end-to-end arterial anastomosis, and group II, the gastroduodenal branch patch. RESULTS: After a mean follow-up of 72 (range 3-174) months, HAT was observed in 19 patients (overall incidence 2.4%). End-to-end anastomosis (group I) was performed in 39.50% (316) of cases, and HAT developed in 14 (4.4%) cases. Branch-patch anastomoses (group II) were carried out in 60.5% (488) of the patients; the presence of HAT was detected in five cases (1.03%) (P = 0.03, P < 0.05). A total of 21 variables were selected in the univariate analysis; however, after the multivariate analysis, all but two of the factors lost statistical significance, and these corresponded to the type of arterial reconstruction (gastroduodenal branch patch vs. end-to-end) and the ABO compatibility. CONCLUSIONS: Liver transplantation with compatible grafts using branch-patch anastomosis for the arterialization (both manipulative by the transplant team) reduces HAT-derived loss of grafts, with the consequent increase in graft availability and reduced mortality rate on the waiting list.