Search

A clinical study was designed to evaluate the tolerance of cancer patients to liposome-associated doxorubicin (L-DXR). The liposomes used contain phosphatidylglycerol, phosphatidylcholine, cholesterol, and DXR intercalated in the lipid bilayer, and have a mean size in the range of 0.3–0.5 μm. Thirty-two patients, most of them with primary or metastatic liver cancer refractory to conventional therapy, were entered into the study. A total of 69courses of therapy was administered by intravenous infusion of a suspension of L-DXR (0.5-2.0 mgDXR/ml) in physiologic saline at an approximate rate of 2 ml/mingiven on a 3-week intermittent schedule. The L-DXR and phospholipid doses were escalated from 20 mg/m2and 0.3 g/m2to 120 mg/m2and 3.2 g/m2respectively. Treatment was generally well tolerated and acute toxic effects such as nausea and vomiting were mild and infrequent. Chills and fever (>38.0°C) were observed in three patients during infusion of L-DXR and in seven patients 6–12 hafter the end of infusion. Median WBC nadir counts were 2700, 2300and 700/μlat 85, 100and 120 mg/m2respectively. All three patients receiving 120 mg/m2developed grade 4leukopenia and fever requiring intravenous antibiotics, and, in two of them, severe stomatitis (grades 3and 4) was observed. Significant hair loss was apparent in all patients receiving doses higher than 50 mg/m2. The maximal tolerated dose of L-DXR appears to be 120 mg/m2, with leukopenia and stomatitis being the dose-limiting factors. While the subacute toxicity of L-DXR appears to be qualitatively similar to that of free DXR, its tolerance exceeds the recommended dose of free DXR (75 mg/m2) in the standard 3-weekly schedule.

During the last decade the frequency of therapy-related acute leukemia (t-leuk) and myelodysplastic syndrome (t-MDS) has been increasingly observed. Over the past 15 years, we treated 56 patients with t-leuk who had received prior chemotherapy (39%), radiotherapy (11%), or both (45%). The drugs received included alkylating agents and topoisomerase II inhibitors. The primary tumors included hematological malignancies (49%) and solid tumors such as breast or ovarian cancer. The median age at diagnosis of the primary tumor was relatively young (43 years +/- 18). Twelve patients had more than one primary tumor and 31 patients had a family history of malignancy. Karyotypic abnormalities were found in 91% of the patients. Prognosis was uniformly poor, with an overall median survival of 10 months. Twelve of the 18 patients examined (67%) had a multidrug resistance phenotype. P53 genes of the leukemic cells, as well as the original tumors, were analyzed in 21 patients using polymerase chain reaction (PCR) with single-stranded conformation polymorphism analysis followed by sequencing. P53 mutations were identified in 38% of these patients, a relatively high prevalence compared with other forms of MDS or de novo acute myeloid leukemia. Mutations were nongermline and restricted to the leukemic cells. We identified different p53 mutations in the various primary tumors of individual patients. The presence of a mutator phenotype was assessed by PCR analysis of microsatellites in eight loci (one trinucleotide repeat sequence, four dinucleotide, and three mononuclear repeat sequences). Microsatellite instability in two to seven loci were found in 15 of 16 (94%) of the patients. This instability is compatible with a mutator phenotype, which predisposes the patients to the development of malignancies including t-leuk.

Voltage-gated K+ channels isolated from mammalian brain are composed of alpha and beta subunits. Interaction between coexpressed Kv1.1 (alpha) and Kvbeta1.1 (beta) subunits confers rapid inactivation on the delayed rectifier-type current that is observed when alpha subunits are expressed alone. Integrating electrophysiological and biochemical analyses, we show that the inactivation of the alphabeta current is not complete even when alpha is saturated with beta, and the alphabeta current has an inherent sustained component, indistinguishable from a pure alpha current. We further show that basal and protein kinase A-induced phosphorylations at Ser-446 of the alpha protein increase the extent, but not the rate, of inactivation of the alphabeta channel, without affecting the association between alpha and beta. In addition, the extent of inactivation is increased by agents that lead to microfilament depolymerization. The effects of phosphorylation and of microfilament depolymerization are not additive. Taken together, we suggest that phosphorylation, via a mechanism that involves the interaction of the alphabeta channel with microfilaments, enhances the extent of inactivation of the channel. Furthermore, phosphorylation at Ser-446 also increases current amplitudes of the alphabeta channel as was shown before for the alpha channel. Thus, phosphorylation enhances in concert inactivation and current amplitudes, thereby leading to a substantial increase in A-type activity.

Kv1.1/Kvbeta1.1 (alphabeta) K+ channel expressed in Xenopus oocytes was shown to have a fast inactivating current component. The fraction of this component (extent of inactivation) is increased by microfilament disruption induced by cytochalasins or by phosphorylation of the alpha subunit at Ser-446, which impairs the interaction of the channel with microfilaments. The relevant sites of interaction on the channel molecules have not been identified. Using a phosphorylation-deficient mutant of alpha, S446A, to ensure maximal basal interaction of the channel with the cytoskeleton, we show that one relevant site is the end of the C terminus of alpha. Truncation of the last six amino acids resulted in alphabeta channels with an extent of inactivation up to 2.5-fold larger and its further enhancement by cytochalasins being reduced 2-fold. The wild-type channels exhibited strong inactivation, which could not be markedly increased either by cytochalasins or by the C-terminal mutations, indicating that the interaction of the wild-type channels with microfilaments was minimal to begin with, presumably because of extensive basal phosphorylation. Since the C-terminal end of Kv1.1 was shown to participate in channel clustering via an interaction with members of the PSD-95 family of proteins, we propose that a similar interaction with an endogenous protein takes place, contributing to channel connection to the oocyte cytoskeleton. This is the first report to assign a modulatory role to such an interaction: together with the state of phosphorylation of the channel, it regulates the extent of inactivation conferred by the beta subunit.

The growth promoting activity of the subendothelial extracellular matrix (ECM) is attributed to sequestration of basic fibroblast growth factor (bFGF) by heparan sulfate proteoglycans and its regulated release by heparin-like molecules and heparan sulfate (HS) degrading enzymes. HS is also involved in bFGF receptor binding and activation. The present study focuses on the growth promoting activity and bFGF binding capacity of sulfate-depleted ECM. Corneal endothelial cells (EC) maintained in the presence of chlorate, an inhibitor of phosphoadenosine phosphosulfate synthesis, produced ECM containing 10-15% of the sulfate normally present in ECM. Incorporation of sulfate into HS was reduced by more than 90%. Binding of 125I-bFGF to sulfate-depleted ECM was reduced by 50-60% and only about 10% of the ECM-bound bFGF was accessible to release by heparin. Incubation of 125I-bFGF on top of native ECM resulted in dimerization of the ECM-bound bFGF, but there was a markedly reduced binding and dimerization of bFGF on sulfate-depleted ECM. ECM produced in the presence of chlorate contained a nearly 10-fold less endogenous bFGF as compared to native ECM and exerted little or no mitogenic activity toward vascular EC and 3T3 fibroblasts. In other studies, we investigated the interaction between chlorate-treated vascular EC and either native or sulfate-depleted ECM. Exogenous heparin stimulated the proliferation of chlorate-treated EC seeded on native ECM, suggesting its interaction with ECM-bound bFGF and subsequent presentation to high affinity cell surface receptors. On the other hand, heparin had no effect on chlorate-treated cells seeded in contact with sulfate-depleted ECM or regular tissue culture plastic. Altogether, the present experiments indicate that heparan sulfate proteoglycans associated with the cell surface and ECM act in concert to regulate the bioavailability and growth promoting activity of bFGF. While HS in the subendothelial ECM functions primarily in sequestration of bFGF in the vicinity of responsive cells, HS on cell surfaces is playing a more active role in displacing the ECM-bound bFGF and its subsequent presentation to high affinity signal transducing receptors.

Pharmacokinetic and imaging studies in 19 patients receiving liposome-entrapped adriamycin (L-ADM) were carried out within the framework of a Phase I clinical trial (Gabizon et al., 1989a). The formulation of L-ADM tested consisted of 0.2 microM-extruded multilamellar vesicles composed of egg phosphatidylcholine, egg-derived phosphatidyl-glycerol (PG), cholesterol, and ADM intercalated in the fluid lipid bilayer. Plasma clearance of total drug extracted from the plasma after L-ADM infusion followed a biexponential curve with a pattern similar to that reported for free ADM. The plasma concentration of drug circulating in liposome-associated from was also measured in a subgroup of seven patients. Liposome-associated drug was found to be rapidly cleared from plasma. Its ratio to non-liposome-associated drug appeared to correlate with liver reserve, with highest ratios in patients with normal liver function. Liposome clearance, as measured by the plasma concentration of PG in three patients was slower than the clearance of liposome-associated ADM, suggesting that liposomes lose part of their drug payload during circulation. To learn about the liposome organ distribution, imaging studies were carried out with 111Indium-deferoxamine labelled liposomes of the same composition. Liposomes were cleared predominantly by liver and spleen and to a lesser extent by bone marrow in seven out of nine patients. In two patients with active hepatitis and severe liver dysfunction, there was minimal liver uptake and increased spleen and bone marrow uptake. Except for one hepatoma patient, intrahepatic and extrahepatic tumours were not imaged by liposomes, suggesting that liposome uptake is restricted to cells of the reticulo-endothelial system (RES).(ABSTRACT TRUNCATED AT 250 WORDS)

We have recently shown that the rat brain Kv1.1 (RCK1) voltage-gated K+ channel is partially phosphorylated in its basal state in Xenopus oocytes and can be further phosphorylated upon treatment for a short time with a cAMP analog (Ivanina, T., Perts, T., Thornhill, W. B., Levin, G., Dascal, N., and Lotan, I. (1994) Biochemistry 33, 8786-8792). In this study, we show, by two-electrode voltage clamp analysis, that whereas treatments for a short time with various cAMP analogs do not affect the channel function, prolonged treatment with 8-bromoadenosine 3',5'-cyclic monophosphorothioate ((Sp)-8-Br-cAMPS), a membrane-permeant cAMP analog, enhances the current amplitude. It also enhances the current amplitude through a mutant channel that cannot be phosphorylated by protein kinase A activation. The enhancement is inhibited in the presence of (Rp)-8-Br-cAMPS, a membrane-permeant protein kinase A inhibitor. Concomitant SDS-polyacrylamide gel electrophoresis analysis reveals that this treatment not only brings about phosphorylation of the wild-type channel, but also increases the amounts of both wild-type and mutant channel proteins; the latter effect can be inhibited by cycloheximide, a protein synthesis inhibitor. In the presence of cycloheximide, the (Sp)-8-Br-cAMPS treatment enhances only the wild-type current amplitudes and induces accumulation of wild-type channels in the plasma membrane of the oocyte. In summary, prolonged treatment with (Sp)-8-Br-cAMPS regulates RCK1 function via two pathways, a pathway leading to enhanced channel synthesis and a pathway involving channel phosphorylation that directs channels to the plasma membrane.

Six patients with spinal cord compression as the presenting symptom of malignant lymphoma are described. These patients suffered from back pain for several months and were diagnosed after sudden paraparesis appeared. Five patients were treated by operative decompression followed by local irradiation, and all regained their motor function. A sixth patient presented with a more insidious paraparesis. A bone marrow aspiration established the diagnosis of malignant lymphoma, and this patient recovered with radiation and steroids alone. Thus, we recommend considering malignant lymphoma as a possible cause of acute cord compression, attempting to establish the diagnosis on an emergency basis within several hours, and attempting to achieve decompression with local radiotherapy and intravenous dexamethasone.

Cancer is the second leading cause of death in women during the childbearing years. Breast can cer is the most common malignancy presenting during pregnancy and lactation. Treatment with antineoplastic agents in this group of patients is problematic due to their potential teratogenicity. A case report is presented of a pregnant woman who received neo-adjuvant chemotherapy for locally advanced carcinoma of the breast. The patient received a total of four courses of cyclophospha mide, doxorubicin and 5-fluorouracil, before deliv ery of a child healthy in all systems. We discuss the use of cytotoxic drugs during pregnancy and indi cate some of the dilemas facing the treating physi cian. The authors join in the call for the establish ment of an international registry of children born to mothers who receive cytotoxic drugs during pregnancy.

Multiple tumor marker analysis (CYFRA 21-1, TPS and CEA) in Lung Cancer was studied in 212 patients aiming to define specificity and sensitivity as well as treatment efficacy. We used 95% specificity versus benign lung pathology in 74 pts with infectious, non-infectious and obstructive lung diseases. Cut-off values of 2.8ng/ml, 196U/L and 4.8ng/ml for CYFRA 21-1 (CYFRA), TPS and CEA respectively were used. According to histological type of the tumor, the sensitivities were the following:Sensitivity (%)Lung carcinomasNo PtsCYFRATPSCEAa) Adeno (Ad)3735.132.448.6b) Squamous (Sq)3151.236.735.5c) Adenosquamous (ASq)475.050.050.0d) Undifferentiated825.037.550.0e) Small (S)1741.247.152.9Metastasis to lung3441.335.344.1Pleural mesothelioma (PM)742.942.90For Sq and ASq CYFRA was the leading marker compared to TPS and CEA. Increased sensitivity for Ad, Sq and S was obtained by the combined determination of the markers CYFRA, TPS and CEA up to 67.6%, 70.9% and 76.5%, respectively TPS and CYFRA showed a high sensitivity for PM while CEA showed no sensitivity at all. A high correlation between CYFRA and TPS (r=0.7) was found for all types of lung cancer. Serial measurements of these markers were useful in determining the effect of therapy or recurrence of disease. This study indicates the clinical relevance of tumor marker panels for lung cancer.

The combination of C.C.C was delivered to 30 patients with AOC. Of these patients 24 had suboptimally debulked and 6 had optimally debulked tumors. C.C.C regimen was given as follows: Carboplatin 200mg/m2d1, Cisplatin 60mg/m2d2 and Cyclophosphamide 550mg/m2d1, 2 q 4 weeks, for 6 cycles. Of 24 patients with sub-optimally debulked, measurable disease 23 (96%) had a clinical response, including 18 (75%) with clinical complete response (CR), of whom 15 underwent a second look laparotomy. Macroscopic CR was found in 10 (42%) patients of whom 6 (25%) had a pathologic CR. After a median follow-up duration of 16 months median survival is pending. For all 30 patients, grade IV leucopenia was noted in 50% and leucopenic fever in 23% of the patients. Grade IV thrombocytopenia was noted in 20%. No other grade III–IV toxicity was noted. There was no toxic death. 90–100% of planned dose was administered to 87% of pts, while 13% received 80–89% of the planned dose. C.C.C is active and safe in ovarian cancer.

Five hundred and twenty-one patients with ABC were randomized to receive PTX over 3-hr or 24-hr q 3 wks at an initial dose of 175mg/m2(with escalation when possible). The pre-randomization strata were defined according to prior chemotherapy (CT): none, adjuvant CT only, CT for ABC. Two-thirds of the patients had prior anthracycline exposure; 24% of these were anthracycline resistant, i.e. progressing on or relapsing within 6 months of an anthracycline regimen.The response rate was 29% in the 3-hr vs 32% in the 24-hr (P=0.629). It was 28% in both arms among anthracycline pretreated patients. Among all patients, treatment over 24-hr resulted in a longer time to progression (TTP) (median 3.8 mos vs 4.6 mos: P=0.021) and survival time (median 9.8 mosvs 13.4 mos; P=0.021). This difference was not apparent after adjustment for prognostic factors, TTP: P=0.081, survival: P=0.099. Treatment was well tolerated as documented by the # of crs administered (median 6 (1–22+) vs 7 (1–21); P<0.01). More patients in the 3-hr arm had their PTX dose escalated (65% in the 3-hr vs 33% in the 24-hr. P<0.001), resulting in an increased dose intensity (62 vs 57mg/m2/wk; P<0.001). The 2 treatment schedules were not equitoxic even after individual dose adjustments. The 24-hr infusion resulted in more severe hematologic (30% vs 79% grade IV neutropenia, P<0.001; 1% vs 17% febrile neutropenia, P<0.001), and GI toxicity (22% vs 45% mucositis, P<0.001; 25% vs 41% diarrhea, P<0.001). The 3-hr infusion with its higher dose intensity resulted in a higher incidence of peripheral neuropathy (78% vs 65%, P=0.001). To evaluate the risk-benefit ratio associated with therapy, we retrospectively analyze the time to either progression or to clinically important adverse events (febrile neutropenia, severe hypersensitivity reaction, and severe neuropathy), and found no statistically significant difference between the two arms (median 3.3 mos vs 3.4 mos; P=0.243). In the palliative setting, the 24-hr infusion of PTX had some efficacy advantage, but did not result in a significant increase in patient benefit as compared to the 3-hr infusion. This trial confirms the activity of PTX in the treatment of ABC pts, including anthracycline pretreated patients.