Metabolic signatures of four major histological types of lung cancer cells

Introduction

Histologically lung cancer is classified into four major types: adenocarcinoma (Ad), squamous cell carcinoma (SqCC), large cell carcinoma (LCC), and small cell lung cancer (SCLC). Presently, our understanding of cellular metabolism among them is still not clear.

Objectives

The goal of this study was to assess the cellular metabolic profiles across these four types of lung cancer using an untargeted metabolomics approach.

Methods

Six lung cancer cell lines, viz., Ad (A549 and HCC827), SqCC (NCl-H226 and NCl-H520), LCC (NCl-H460), and SCLC (NCl-H526), were analyzed using liquid chromatography quadrupole time-of-flight mass spectrometry, with normal human small airway epithelial cells (SAEC) as the control group. The principal component analysis (PCA) was performed to identify the metabolic signatures that had characteristic alterations in each histological type. Further, a metabolite set enrichment analysis was performed for pathway analysis.

Results

Compared to the SAEC, 31, 27, 34, 34, 32, and 39 differential metabolites mainly in relation to nucleotides, amino acid, and fatty acid metabolism were identified in A549, HCC827, NCl-H226, NCl-H520, NCl-H460, and NCl-H526 cells, respectively. The metabolic signatures allowed the six cancerous cell lines to be clearly separated in a PCA score plot.

Conclusion

The metabolic signatures are unique to each histological type, and appeared to be related to their cell-of-origin and mutation status. The changes are useful for assessing the metabolic characteristics of lung cancer, and offer potential for the establishment of novel diagnostic tools for different origin and oncogenic mutation of lung cancer.

     

Reactions of iron-sulfur proteins with the aquated electron

The reaction of parsley 2Fe-2S ferredoxin in the normal oxidized state with e_aq^? generated by pulse radiolysis techniques has been studied at ～25°C, pH 7–8, I = 0.10 M (NaClO₄). Rate constants k_e (e_aq^? decay) and k_p (protein absorbance change) are the same, second-order rate constant 9.7 × 10⁹ M^?1 sec^?1. The reaction exhibits close to 100% efficiency. With 8Fe-8S ferredoxin from Clostridium pasteurianum under identical conditions it now appears that k_p (although sometimes significantly smaller) is equal to k_e. Varying efficiencies are also observed with this protein depending on the batch used. The reasons for such variable behavior are not fully understood. With oxidized and reduced forms of Chromatium v. high-potential iron-sulfur protein (HIPIP), k_e and k_p are essentially the same, but the highest efficiency observed is only ～50%. The prevailing pattern is therefore that rate constants k_e and k_p are generally in step for proteins having a single (or identical) active site(s). When the active site is buried as with HIPIP the efficiency of the reaction appears to decrease.     

Fluorescence demonstration of a cathepsin H-like protease in cardiac, skeletal and vascular smooth muscles

Summary A cathepsin H-like enzyme was localized by histochemical techniques in cardiac muscle, extensor digitorum longus and soleus skeletal muscles, and vascular smooth muscle. Using the specific exopeptidase activity of this enzyme against the substrate arg-4-methoxy--naphthylamide, valid histochemical assay conditions were developed. More fluorescent granules were observed in cardiac muscle than in the soleus and about equal amounts in vascular smooth muscle and the extensor digitorum longus. The reaction rate was enhanced by chloride ions and inhibited by 1mm p-chloromercuribenzoate. The maximal activity was observed between pH 5.5 and 6.0. Chemical fixation with periodate-lysine-paraformaldehyde preserved a small amount of enzymatic activity.     

Spontaneous sexual differentiation of Mesocestoides corti tetrathyridia in vitro

Barrett N. J., Smyth J. D. and Ong S. J. 1982. Spontaneous sexual differentiation of Mesocestoides corti tetrathyridia in vitro. International Journal for Parasitology12: 315–322. Tetrathyridia of Mesocestoides corti, from the body cavity of mice, maintained in the laboratory by intraperitoneal infection, were used for in vitro culture. In an initial experiment, after 50 days asexual multiplication in vitro one tetrathyridium spontaneously segmented and developed into a sexually mature adult. Further experiments were carried out in an attempt to determine the conditions favouring segmentation and sexual differentiation. A combination of 5 or 10 ml liquid medium S1OE.H (basically composed of CMRL 1066 and foetal calf serum with supplements) changed every 3 days, in a Leighton tube (19 × 105 mm), rotated at 38°C and gassed with 10 or 20% CO₂, containing between 100 and 200 tetrathyridia, has proved to be most suitable so far. Numerous adult worms with normal male and female genitalia have been obtained in this system. However, segmentation is sporadic, rather than consistent and only a few shelled eggs with hooked oncospheres have so far been obtained, suggesting that impregnation and fertilization in vitro is not fully comparable with that in vivo.     

Immune islet killing mechanisms associated with insulin-dependent diabetes: in vitro expression of cellular and antibody-mediated islet cell cytotoxicity in humans

In previous work we have shown that some bacteria can bind to human lymphocytes and can be used to identify lymphocyte subpopulations in conventionally stained blood smears. These bacteria are of different species or genera, which makes it difficult to study the binding mechanism. Also, the main marker for B cells, Brucella melitensis, is of very small size and highly pathogenic. Here we show that B cells as well as some of the T cell subpopulations can be identified by different mutants obtained from a strain of an Escherichia coli. Two procedures were used to generate mutants. First, E. coli-YS57 (pro-his-trp-) was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine and the binding to mouse spleen cells was used as a selective pressure. Second, phage-resistant mutants of E. coli-YS57 were obtained and tested for the ability to bind to lymphocytes. Out of 10 strains selected by the former procedure, 5 bound to a significant number of human lymphocytes. All four phage-resistant mutants bound to human lymphocytes. Out of the total of nine mutants that bound to lymphocytes, six bound consistently, i.e., they bound to similar percentages of peripheral blood lymphocytes from different normal donors. One phage-resistant mutant, E. coli USC-106, bound only to B cells. The subpopulations of lymphocytes identified by the mutants were essentially the same as those identified by different species or genera of bacteria. We concluded that E. coli mutants can be obtained that identify human lymphocyte subpopulations and that one of these mutants recognizes B cells; these mutants may be used to study the nature of the receptors for bacteria on lymphocytes, which appear to have a lectin-like nature.     

Mutagenicity studies of ambient airborne particles. II. Comparison of extraction methods

Organic materials were extracted with acetone from airborne particles by shaking, soxhletion and sonication for varying durations. 4-h, 1-h and 1/8-min extractions by shaking, soxhletion and sonication, respectively gave maximum his+ revertants with the Ames Salmonella/microsome assay. In a comparative study of extraction methods, sonication gave the highest and soxhletion the lowest mutagenic response. It appears that sonication with acetone is the best procedure for the extraction of mutagens from airborne particles as shown by Ames assay and Arar assay systems in Salmonella typhimurium.     

Microtubule assembly and disassembly at alkaline pH

Although it is now apparent that the intracellular pH may rise considerably above neutrality under physiological conditions, information on the effect of alkaline pH on microtubule assembly and disassembly is still quite fragmentay. We have studied the assembly/disassembly of bovine brain microtubule protein at alkaline pH in vitro. When microtubules are assembled to a new steady state at pH less than 7 and pH is then made more alkaline, they undergo a rapid disassembly to a new steady state. This disassembly is reversed by acidification. The degree of disassembly is determined largely by the pH- dependence of the critical concentration, which increases five to eight times, from pH 7 to 8. A fraction of assembly-incompetent tubulin is identified that increases with pH, but its incompetency is largely reversed with acidification. Measurements of microtubule lengths are used to indicate that disassembly occurs by uniform shortening of microtubules. A comparison of shortening by alkalinization with dilution suggests that the intrinsic rate of disassembly is accelerated by increasing pH. The capacity for initiating assembly is progressively lost with incubation at alkaline pH (although some protection is afforded by sulfhydryl-reducing agents). However, direct assembly from depolymerized mixtures is possible at least up to pH 8.3, and the steady state achieved at these alkaline pH values is stable. Such preparations are readily disassembled by cold and podophyllotoxin (PLN). Disassembly induced by PLN is also markedly enhanced at alkaline pH, suggesting a corresponding enhancement of “treadmilling.” The implications of physiological events leading to alkaline shifts of pH for microtubule assembly/disassembly are discussed, particularly in the light of recent hypotheses regarding treadmilling and its role in controlling the distribution of microtubules in vivo.     

Fuel alcohol biosynthesis by Zymomonas anaerobia: Optimization studies

The optimum operating conditions for growth and ethanol production of Zymomonas anaerobia ATCC 29501 were established. The optimum pH range and temperature were found to be 5.0-6.0 and 35 degrees C, respectively. Based on the results obtained from the temperature optimization study, an Arrhenius-type temperature relationship for the specific growth rate was developed. The growth and ethanol production of this microbe also have been optimized in terms of concentrations of glucose, essential nutrients, and minerals. With optimum medium and operating conditions, an ethanol concentration of 96 g/L was obtained in 23 h. Both growth and ethanol yield coefficients in dependence on initial glucose concentrations were determined.