Docetaxel (Taxotere) in combination chemotherapy and in association with thoracic radiotherapy for the treatment of non-small-cell lung cancer. Thoracic Oncology Program.

Docetaxel is one of the most active single agents for the treatment of non-small-cell lung cancer. Given the preclinical indications for synergy and the lack of cross-resistance with other active agents in this disease, clinical trials of docetaxel combinations have been undertaken. Phase I and II clinical trials of docetaxel in combination with cisplatin, carboplatin, gemcitabine, vinorelbine, or thoracic radiation for patients with non-small-cell lung cancer were reviewed. The endpoint for phase I trials was to define the phase II doses for the docetaxel combinations where overall response rates, median and one year survival were the endpoints. Five phase I-II studies of docetaxel and cisplatin have reported response rates ranging from 21% to 48%. Median survival times ranged from 8 to 13 months, and one-year survivals from 32% to 58%. Combining docetaxel with vinorelbine resulted in a 37% response rate and a median survival of 9.4 months. Docetaxel in combination with gemcitabine produced a response rate of 53%. The adverse events of these combinations were manageable. Responses have also been reported in studies of docetaxel administered with carboplatin or thoracic radiation therapy. Combinations of docetaxel with platinum, vinorelbine, gemcitabine, and radiation were active in non-small-cell lung cancer with acceptable adverse effects. Phase III trials are currently in progress to further define the role of docetaxel combinations in the first-line treatment of this disease.

Effects of mitomycin C and carboplatin pretreatment on multidrug resistance-associated P-glycoprotein expression and on subsequent suppression of tumor growth by doxorubicin and paclitaxel in human metastatic breast cancer xenografted nude mice.

Overexpression of P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP), and several other proteins has been associated with development of multidrug resistance by cancer cells, which represents a significant obstacle to successful treatment by chemotherapy. We had previously demonstrated that a single noncytotoxic dose of mitomycin C (MMC), carboplatin, or one of several other DNA cross-linking agents suppressed mRNA expression of the mdr1 gene coding for Pgp, leading to a subsequent suppression of Pgp protein levels and a concomitant decrease in drug efflux. Pretreatment with MMC led to a 5- to 10-fold decrease in the ED50 for cell killing by a subsequent agent such as the Pgp substrate, doxorubicin, but did not affect killing by the non-Pgp substrate, cisplatin. In this study, we report that MMC and carboplatin each significantly suppressed Pgp protein levels in human MDA-MB-435 cells xenografted as solid tumors into the lateral mammary fat pads of female nude mice, with a similar time course as had previously been observed in cell culture. Pretreatment of mice with MMC or carboplatin 48-72 h prior to receiving either doxorubicin or paclitaxel caused a significantly greater reduction in tumor growth rate compared to either agent alone or the combination given simultaneously. These data suggest that a combination chemotherapy regimen consisting of a DNA cross-linking agent given to modulate the MDR phenotype, followed by a second cytotoxic agent, may be an effective treatment for human patients with de novo or late stage acquired multidrug-resistant malignancies.

ARDS associated with tumor lysis syndrome in a patient with non-Hodgkin's lymphoma.

ARDS developed in association with tumor lysis syndrome (TLS) in a patient with non-Hodgkin's lymphoma. Although a number of life-threatening complications have been noted to occur following TLS, this appears to be the first report of ARDS developing in association with TLS.

Effects of estradiol and environmental temperature changes on rat liver delta 6 microsomal desaturase activity.

The regulation of delta 6 desaturase activity by environmental temperature changes was studied in the microsomal membranes from female and ovariectomized female rat liver. Female rats adapted at 30-32 C for 20-25 days and then shifted to 13-15 C for 5 days showed an increased delta 6 desaturase system. Ovariectomized rats adapted under the same conditions did not show significant changes in this enzyme. The fatty acid compositions of microsomal phosphatidylcholine showed a decrease in arachidonic acid in female rats at 30 C compared to females at 15 C and ovariectomized rats at both temperatures. These results suggest that a modification of ovaric sex hormone levels might be responsible for the different delta 6 desaturase activity in female rats acclimated at both temperatures. In this regard, serum estradiol radioimmunoassay yielded slight differences between the two groups of female rats, suggesting that estradiol could play a role in the regulation of the delta 6 desaturase. The administration of a pharmacological dose of 17-beta estradiol to female and ovariectomized rats kept at 30 and 15 C decreased the delta 6 microsomal desaturase activity. These data suggest that estradiol levels are involved in the regulation of the delta 6 desaturase during cold adaptation.

Effect of different amino acid diets on delta 5, delta 6 and delta 9 desaturases.

A high-protein diet with 45% calories from casein increased delta 6 desaturase activity in rat-liver microsomes. High-protein diets with 45% calories from a synthetic mixture of amino acids in the same proportion as casein decreased the delta 9 desaturase, slightly increased the delta 5 desaturase and greatly increased delta 6 desaturase activities compared with a high-carbohydrate diet. The elimination of phenylalanine and tyrosine from the synthetic mixtures of amino acids increased the delta 6 desaturase activity. Massive amounts of phenylalanine or tyrosine in the diet inhibited delta 6 desaturase activity. Tyrosine and phenylalanine may, by conversion to tyrosine, decrease the activity of the delta 6 desaturase.

Effect of environmental temperature changes on rat liver fatty acid desaturases.

Female rats warm-adapted at 30-32 C for 20-25 days and then shifted to 13-15 C for 12, 24, 48, 72 and 120 hr showed that delta 9 desaturase and fatty acid synthetase activity decay after 24 hr of cold exposure, while delta 6 and delta 5 desaturases were increased after this period of time. These results were confirmed by an increase of arachidonic acid of heart and liver microsomes phosphatidylcholine and a decrease of oleic acid. Neither NADH-cyt b5 reductase nor NADH-cyt c reductase activity of liver microsomes were significantly affected. Male rats warm-adapted under the same conditions and then shifted to 13-15 C for 120 hr did not show significant changes in fatty acid synthetase, delta 9 and delta 6 desaturases and enzymes of the microsomal electron transport chain. Therefore, the desaturase response to environmental temperature changes could be plausibly linked to female hormones.

Turnover of low density lipoproteins in normal and atherosclerotic rabbits.

The turnover and composition of normal and hyperlipemic (h.l.) low density lipoproteins (LDL) of rabbits, were studied. They were obtained by ultracentrifugation and labeled by Bolton and Hunter method. Normal and h.l. LDL labeled with 125I were injected directly and crossed to both groups of rabbits. Normal and h.l. LDL had a different protein/lipid ratio. The analysis of fractional catabolic rate of LDL and the half-life of the phases of rapid and slow decay, show that h.l. LDL had a fractional catabolic rate that is the half of normal LDL and an increased half life of the phases of rapid and slow decay. Apparently, two factors: a) defective LDL receptor in the h.l. rabbit and b) different physico-chemical properties between normal and h.l. LDL, would be the reason for this difference. Besides, when normal and h.l. 125I LDL were injected into h.l. and normal rabbit, respectively, LDL changed according to the injected rabbit, as can be deduced from the analysis of the half life of the phase of slow decay.

Effect of clofibrate on fatty acid desaturation of rats treated with ethanol.

The effect of clofibrate and ethanol in the rat was studied on the following aspects of lipid composition and metabolism: liver delta 5, delta 6 and delta 9 fatty acid desaturases, fatty acid synthetase and fatty acid desaturase microsomal electron transport chain activity and serum cholesterol, triacylglycerols and high (HDL), low (LDL) and very low density lipoprotein (VLDL) levels. Clofibrate administered for 9 days (0.3% W/W) did not modify the relative composition of liver phospholipids and cholesterol, but did diminish triacylglycerol levels increased by ethanol. This effect could be explained by the possible beta-adrenergic blocking properties of clofibrate or by an increased activity of peroxisomal beta-oxidation. Clofibrate also promoted a decrease in serum cholesterol and triacylglycerol levels, delta 6 desaturase activity and a suppression of the electron transport chain as measured by NADH cytochrome b5 reductase and NADH cytochrome c reductase. The drug increased delta 9 desaturase activity and fatty acid synthetase, while no effect could be found in delta 5 desaturase activity. The hypocholesterolenic effect of clofibrate can not be explained through the delta 6 desaturase inhibition, or the fatty acid synthetase enhancement. Ethanol increased the HDL and VLDL and lowered LDL serum concentrations, while clofibrate reversed these results. Considering that clofibrate could have antiatherosclerotic effect in the rat, it is difficult to explain it through these changes in lipoprotein levels, since according to Miller and Miller low HDL levels are predictive of coronary heart disease.

Effect of ethanol administration on fatty acid desaturation.

The effect of ethanol on the fatty acid desaturation by rat liver has been studied using liquid diets of different composition. Acute ethanol administration increased triacylglycerols of total liver lipids, but did not modify significantly the lipidic composition of microsomes. The delta 6 and delta 5 desaturases were inhibited by ethanol whereas the delta 9 desaturase and fatty acid synthetase were apparently modified only by diet composition. NADH-cytochrome (cyt.) c reductase was partially inhibited, whereas NADH-cyt. b5 reductase remained practically unaltered and NADPH-cyt. c reductase activity was enhanced. Decreased electrons supplied by the microsomal cyt. b5 electron transport chain would not be the reason for the inhibition of delta 6 and delta 5 desaturases by ethanol.

Lipid binding properties of a factor necessary for linoleic acid desaturation.

Suspension and centrifugation of crude microsomes of rat liver in low ionic strength solution separated a soluble protein fraction that is necessary for the full activity of the linoleic acid desaturase. The fraction partially purified through Sephadex G-150 still retains lipids which are mainly constituted by phosphatidycholine. Linoleic acid predominates in the fatty acid composition. By NaCl gradient centrifugation and electrophoresis in gelatinized cellulose acetate, the factor behaves like a lipoprotein. The factor binds linoleic acid and linoleyl-CoA that are desaturated to gamma-linolenic acid when incubated with washed microsomes. Albumin does not replace the factor.

Amino acid sequence of Escherichia coli biotin carboxyl carrier protein (9100).

The amino acid sequence of a proteolytic fragment of Escherichia coli biotin carboxyl carrier protein was determined from the structures of overlapping tryptic, thermolytic, and staphylococcal protease peptides together with automated sequenator analyses on the intact protein. The fragment, 82 residues in length, contains the single residue of biocytin of the protein. The relationship of the Mr = 9100 fragment to the native Mr = 22,500 subunit is discussed.

Linoleic acid desaturation activity of liver microsomes of essential fatty acid deficient and sufficient rats.

Studies were carried out to relate the changes of the fatty acid and lipid composition of rat microsomes with the modification of the activity of the linoleic acid desaturation evoked by an essential fatty acid deficient diet. Two steps were shown in the progression of the essential fatty acid deficienty. In a first step shown at three days of essential fatty acid deficiency the fatty acid composition was changed by decreasing linoleic and arachidonic acids and increasing oleic and eicosatrienoic (-9) acids. No change was found in the lipid distribution and approximate V and Km of the linoleic acid desaturation. In this first step the unsaturated/saturated fatty acids ratio fell in spite of the synthesis of eicosatrienoic (n-9) acid that was produced without any change of enzyme activity. In a second step shown at 15 days of essential fatty acid deficiency the change of the fatty acid composition was greater but the unsaturated/saturated acid ratio was restored. An increase of triacylglycerols and a decrease of phospholipids was also detected together with an enhanced activity of linoleic acid desaturation (higher approximate V) and a higher approximate Km. The increase of the V of linoleic acid desaturation is considered to be evoked by an increased level of active delta-6 desaturase. The increased activity of the delta-6 desaturase in this second period is a secondary and important response of the cell to maintain the unsaturated : saturated acid ratio and fluidity of the membrane.

Separation of a protein factor necessary for the oxidative desaturation of fatty acids in the rat.

Microsomes from rat liver were extracted by low ionic strength solutions. Extracted microsomes lost most of the linoleic acid desaturation activity. The addition of the extract back into the extracted microsomes was necessary to restore full desaturation activity. The soluble fraction had no desaturation activity. The existence of a soluble factor loosely bound to the microsomes, stable to sonication, and unstable to heat and trypsin digestion was recognized. This protein could not be replaced by albumin. The factor was also essential for the oxidative desaturation of palmitic, stearic, linoleic, and gamma-linolenic acid. The present experiment suggests that the protein factor is not NADH-cytochrome b5 reductase, cytochrome b5, or the cyanide-sensitive factor.

Dietary and hormonal effects upon activity of "soluble" protein and particulate fraction of fatty acid desaturation system of rat liver microsomes.

Rat liver microsomes were extracted with a buffered 0.15 M KCl and 0.25 M sucrose solution and fractionated by centrifugation into a particulate component and a supernatant containing a protein factor necessary for fatty acid desaturation. The delta 6 fatty acid desaturation activity of the extracted microsomes was reduced significantly, and the readdition of the supernatant restored the enzymatic activity to the original value of the whole microsomes. A protein diet or a fat-free diet increased the delta 6 desaturation activity of the whole microsomes. The activating effect was evoked upon the particulate components of the enzymatic desaturation system and not upon the protein factor present in the supernatant. Fasting, refeeding, and refeeding plus glucagon and theophylline treatments of rats also modified the delta 6 desaturation activity of whole liver microsomes. The effect also was evoked on the delta 6 desaturation system tightly bound to the microsomal membrane but not on the protein factor of the supernatant. Accordingly, the protein factor of the supernatant is considered to be different from the cyanide sensitive factor and the desaturase.

Acetyl CoA carboxylase: isolation and characterization of native biotin carboxyl carrier protein.

A large form of biotin carboxyl carrier protein (BCCP(L)) has been isolated from extracts of Escherichia coli. It has a minimal molecular weight of 20,000, according to its behavior on sodium dodecylsulfate-polyacrylamide gel electrophoresis, and contains approximately 1 mol of biotin per 22,000 g of protein. BCCP(L) exhibits K(m) values, in the biotin carboxylase and transcarboxylase half-reactions of acetyl CoA carboxylase, of 2 x 10(-7) M and 4 x 10(-7) M, respectively; these values are 50-100 times lower than those obtained with smaller forms of BCCP previously isolated. Electrophoresis of crude extracts of E. coli indicates that the major biotin-containing protein migrates at the same rate as BCCP(L), which suggests that BCCP(L) is the native form of BCCP in E. coli.

Acetyl CoA carboxylase, II. Deomonstration of biotin-protein and biotin carboxylase subunits.

Previous work has shown that Escherichia coli acetyl CoA carboxylase is composed of two dissimilar protein components, E(a) which contains covalently bound biotin and forms E(a)-CO(2)-from HCO(3)- and ATP, and E(b) which is involved in the transfer of the carboxyl group from E(a)-CO(2)- to acetyl CoA, forming malonyl CoA. E(a) has been dissociated into two subunits at pH 9. One subunit, designated biotin carboxylase, catalyzes a model reaction, the ATP-dependent carboxylation of free (+)-biotin. The other subunit contains covalently bound which is carboxylated by the biotin carboxylase in the course of acetyl CoA carboxylation.