Mark H. Lee

Constitutive phosphorylation of Akt/PKB protein in acute myeloid leukemia: its significance as a prognostic variable.

Constitutive phosphorylation of Akt/PKB protein in acute myeloid leukemia: its significance as a prognostic variable

Interleukin 12 Gene Therapy of Cancer by Peritumoral Injection of Transduced Autologous Fibroblasts: Outcome of a Phase I Study

A phase I dose-escalation clinical trial of peritumoral injections of interleukin 12 (IL-12)-transduced autologous fibroblasts was performed in patients with disseminated cancer for whom effective treatment does not exist. The goals of this study were to assess the safety and toxicities as well as the efficacy, and ancillarily the immunomodulatory effects, of peritumoral IL-12 gene transfer. Primary dermal fibroblasts cultured from the patients were transduced with retroviral vector carrying human IL-12 genes (p35 and p40) as well as the neomycin phosphotransferase gene (TFG-hIL-12-Neo). Patients received four injections at intervals of 7 days. Nine patients were enrolled in this dose-escalation study, with secreted IL-12 doses ranging from 300 ng/24 hr for the first three patients to 1000, 3000, and 5000 ng/24 hr for two patients in each subsequent dosage level. Although a definite statement cannot be made, there appears to be perturbation of systemic immunity. Also, the locoregional effects mediated by tumor necrosis factor alpha (TNF-alpha) and CD8+ T cells were observed with tumor regression. Treatment-related adverse events were limited to mild to moderate pain at the injection site; clinically significant toxicities were not encountered. Transient but clear reductions of tumor sizes were observed at the injected sites in four of nine cases, and at noninjected distant sites in one melanoma patient. Hemorrhagic necrosis of tumors was observed in two melanoma patients. These data indicate that gene therapy by peritumoral injection of IL-12-producing autologous fibroblasts is feasible, and promising in patients with advanced cancer.

Phase II Study of High-Dose Lovastatin in Patients with Advanced Gastric Adenocarcinoma

Lovastatin, an inhibitor of mevalonate synthesis,demonstrated in vitro antitumor activity against avariety of human cancer cells, especially in gastricadenocarcinoma cells at pharmacologically achievableconcentrations. To determine the antitumor activity of thisdrug in advanced measurable gastric adenocarcinoma as well asto assess the toxicities and the pharmacokinetic features, wecarried out a phase II study of high-dose lovastatin. Patientsreceived lovastatin 35 mg/kg/day for 7 consecutive days, withubiquinone (60 mg qid po) to prevent rhabdomyolysis. Thetreatment was repeated every 28 days. From March 1996 toJanuary 1997, 16 patients (median age, 57 years; range,34–68) were entered into the study, 14 of whom wereevaluated for response and toxicity. No patient achieved aresponse. A total of 28 cycles were administered. The mediannumber of cycles was 2 (range, 1 to 4). Anorexia was the mostcommon toxicity (64%), but decreased oral intake wasobserved only in 3 cycles. Two patients developed myalgia withelevated muscle enzyme. When used in this dosage and schedule,lovastatin does not appear to be effective for patients withadvanced gastric adenocarcinoma.

Arsenic trioxide inhibits the growth of A498 renal cell carcinoma cells via cell cycle arrest or apoptosis.

Previously, we showed that arsenic trioxide potently inhibited the growth of myeloma cells and head and neck cancer cells. Here, we demonstrate that arsenic trioxide inhibited the proliferation of all the renal cell carcinoma cell lines (ACHN, A498, Caki-2, Cos-7, and Renca) except only one cell line (Caki-1) with IC(50) of about 2.5-10 microM. Arsenic trioxide induced a G(1) or a G(2)-M phase arrest in these cells. When we examined the effects of this drug on A498 cells, arsenic trioxide (2.5 microM) decreased the levels of CDK2, CDK6, cyclin D1, cyclin E, and cyclin A proteins. Although p21 protein was not increased by arsenic trioxide, this drug markedly enhanced the binding of p21 with CDK2. In addition, the activities of CDK2- and CDK6-associated kinase were reduced in association with hypophosphorylation of Rb protein. Arsenic trioxide (10 microM) also induced apoptosis in A498 cells. Apoptotic process of A498 cells was associated with the changes of Bcl-(XL), caspase-9, caspase-3, and caspase-7 proteins as well as mitochondria transmembrane potential (Deltapsi(m)) loss. Taken together, these results demonstrate that arsenic trioxide inhibits the growth of renal cell carcinoma cells via cell cycle arrest or apoptosis.

Cytoplasmic Mislocalization of p27Kip1 Protein Is Associated with Constitutive Phosphorylation of Akt or Protein Kinase B and Poor Prognosis in Acute Myelogenous Leukemia

Cyclin-dependent kinase inhibitor p27Kip1 functions at the nuclear level by binding to cyclin E/cyclin-dependent kinase-2. It was shown that Akt or protein kinase B (Akt/PKB)-dependent phosphorylation of p27Kip1 led to the cytoplasmic mislocalization of p27Kip1, suggesting the potential abrogation of its activity. Here, we evaluated the localization of p27Kip1 protein in leukemic blasts in relation to Akt/PKB phosphorylation and clinical outcomes in acute myelogenous leukemia (AML). Western blot analysis of the nuclear and cytoplasmic fractions revealed a heterogenous localization pattern of p27Kip1 in AML. Cytoplasmic mislocalization of p27Kip1 was significantly associated with the constitutive serine473 Akt/PKB phosphorylation in AML cells (P < 0.05). Transfection of U937 cells with an expression construct encoding the constitutively active form of Akt/PKB resulted in a remarkable increase in the levels of cytoplasmic p27Kip1. Whereas the transfection of U937 cells with a construct encoding dominant-negative Akt/PKB resulted in a recovery of nuclear localization of p27Kip1. Both the disease-free survival and overall survival are significantly shorter in AML cases with high cytoplasmic to nuclear ratio of p27Kip1 localization compared with the cases with low cytoplasmic to nuclear ratio (P = 0.0353, P = 0.0023, respectively). Multivariate analysis indicated that the cytoplasmic to nuclear ratio of p27Kip1 localization was an independent prognostic variable for both disease-free survival and overall survival (P = 0.043, P = 0.008, respectively). These findings additionally extend our understanding of the role of p27Kip1 in AML, and buttress the case of p27Kip1 mislocalization as a prognostic indicator and Akt/PKB/p27Kip1 pathway as a ready target for antileukemia therapy.

Gefitinib (ZD1839) Monotherapy as a Salvage Regimen for Previously Treated Advanced Non-Small Cell Lung Cancer

Purpose: A worldwide compassionate-use program has enabled >42,000 patients with advanced non-small cell lung cancer (NSCLC) to receive gefitinib treatment. Here we report the outcome of gefitinib therapy in patients who enrolled in the “Iressa” Expanded Access Program at the Samsung Medical Center. Experimental Design: Patients with advanced or metastatic NSCLC who had progressed after prior systemic chemotherapy and for whom no other treatment option was available were eligible to receive gefitinib treatment as part of the Expanded Access Program. A post hoc assessment of potential prognostic factors for response and survival was performed by multivariate analysis. Results: All 111 evaluable patients had stage IV disease; most patients had a baseline performance status of 2 [n = 52 (47%)] or 3 [n = 18 (16%)] and had received ≥2 prior chemotherapy regimens (56%). The objective response rate was 26%, the disease control rate (measured over ≥8 weeks) was 40%, and the 1-year survival rate was 44%. Adenocarcinoma histology was associated with better response and disease control rates, and a performance status of 0–2 was also associated with a better disease control rate. Both of these factors, as well as female gender, were significantly associated with longer survival. Gefitinib was well tolerated; the most common adverse event was grade 1 skin rash. Conclusions: Gefitinib demonstrated significant antitumor activity and a favorable tolerability profile in this series of NSCLC patients with poor prognosis.

Docetaxel plus cisplatin as second-line therapy in metastatic or recurrent advanced gastric cancer progressing on 5-fluorouracil-based regimen.

The purpose of this study was to determine the activity and safety of docetaxel plus cisplatin as second-line chemotherapy for advanced gastric cancer. This trial included patients who had failed first-line chemotherapy with a 5-fluorouracil regimen within 1 year before their enrollment. After registration, patients were treated with docetaxel intravenously at a dose of 60 mg/m2 given over 1 hour followed by cisplatin 60 mg/m2 given over 2 hours. The treatment was continued every 3 weeks until disease progression or unacceptable toxicity was detected. Forty-three patients were registered and 41 were assessable for response. Seven partial responses were observed (17.1% of the “evaluable” patients; 95% confidence interval [CI], 0–29) with a median response duration of 3.9 months. Stable disease was documented in 2 cases (4.9%). The median survival was 5.8 months (95% CI, 3.4–8.3), resulting in a 1-year survival rate of 23%. Tolerance was acceptable, with the main toxicity being neutropenia. The authors conclude that second-line chemotherapy with docetaxel plus cisplatin for advanced gastric cancer is feasible with an acceptable toxicity level.

Intestinal Lymphoma: Exploration of the Prognostic Factors and the Optimal Treatment

Primary gastrointestinal (GI) lymphoma accounts for 4% to 20% of all non-Hodgkins lymphomas (NHL), being the most common extranodal site of presentation. However, the optimal management of intestinal lymphoma has not yet been established. During the period of 1994 to 2001, we retrospectively analyzed the clinical features of 67 intestinal lymphoma patients diagnosed according to the Lewins definitions. The most frequently involved location was ileocecal (35.8%) followed by small bowel (31.3%), large bowel (19.4%), and multiple GI involvement (13.4%). The estimated 5-year overall survival rate was 53%. Out of all treated patients, 49.2% achieved complete response. The advanced stage, poor performance and T-cell phenotype had an adverse prognostic influence on overall survival. In localized diseases (stage 1 and 2), the primary surgical treatment had the most favorable influence on failure-free survival (P < 0.05). The resection of localized intestinal lymphoma may be appropriate as the primary treatment.

L‐ascorbic acid represses constitutive activation of NF‐κB and COX‐2 expression in human acute myeloid leukemia, HL‐60

There is increasing evidence that l‐ascorbic acid (LAA) is selectively toxic to some types of cancer cells at pharmacological concentrations, functioning as a pro‐oxidant rather than as an anti‐oxidant. However, the molecular mechanisms by which LAA initiates cellular signaling leading to cell death are still unclear. In an effort to gain insight into these mechanisms, the effects of LAA on eukaryotic transcription nuclear factor NF‐κB and cyclooxygenase‐2 (COX‐2) expression were investigated. In the present study, LAA suppressed DNA binding activity of NF‐κB, composed of a p65/p50 heterodimer, through inhibition of degradation of inhibitory κB‐α (IκB‐α) and prevention of nuclear translocation of p65. The inhibitory effect of LAA on NF‐κB activity was dependent upon glutathione levels in HL‐60 cells, as well as generation of H2O2 but not superoxide anion. LAA also downregulated the expression of COX‐2, which has a NF‐κB binding site on its promoter, through repressing NF‐κB DNA binding activity. Moreover, cotreatment of 1 μM arsenic trioxide (As2O3) with various concentrations of LAA enhanced an LAA‐induced repression of NF‐κB activity and COX‐2 expression. In conclusion, our data suggest that LAA exerts its anti‐tumor activity through downregulation of NF‐κB activity and COX‐2 expression, and these inhibitory effects can be enhanced by co‐treatment with As2O3.

Tuberculosis in hematopoietic stem cell transplant recipients in Korea.

Hematopoietic stem cell transplantation (HSCT) results in impaired cell-mediated immunity, which subsequently increases the risk of infection from bacterial, fungal, and viral pathogens. Mycobacterial infections are commonly seen in immunodefi-cient patients, especially in endemic areas. Several series that have reviewed mycobacterial infections in HSCT patients reported incidences varying from less than 0.1% to 5.5%. From February 1996 to July 2003, we retrospectively reviewed records of 295 adult patients who underwent HSCT at Samsung Medical Center, Korea. Mycobacterial infections were diagnosed in 9 (3.1 %) of the 295 transplant recipients. The time from HSCT to tuberculosis (TB) infection ranged from 45 days to 165 days posttransplantation. Analysis at the univariate level indicated that a conditioning regimen with total body irradiation (TBI), chronic graft-versus-host disease, and a previous history of TB infection were significant risk factors for the development of TB infection after HSCT. Multivariate analysis revealed that only a previous history of TB infection and TBI increased the risk of TB infection in HSCT patients (relative risk, 4.8 and 12.5, respectively). Isoniazid prophylaxis in HSCT recipients with only radiologic findings suggestive of past inactive TB infection did not significantly alter the incidence of TB infections(P = .236). In conclusion, a previous history of active TB infection and TBI were significant risk factors of TB infection following HSCT, and isoniazid prophylaxis may benefit HSCT recipients with a previous history of active TB infection.