High-dose intravenous vitamin C combined with cytotoxic chemotherapy in patients with advanced cancer: a phase I-II clinical trial.

BACKGROUND: Biological and some clinical evidence suggest that high-dose intravenous vitamin C (IVC) could increase the effectiveness of cancer chemotherapy. IVC is widely used by integrative and complementary cancer therapists, but rigorous data are lacking as to its safety and which cancers and chemotherapy regimens would be the most promising to investigate in detail. METHODS AND FINDINGS: We carried out a phase I-II safety, tolerability, pharmacokinetic and efficacy trial of IVC combined with chemotherapy in patients whose treating oncologist judged that standard-of-care or off-label chemotherapy offered less than a 33% likelihood of a meaningful response. We documented adverse events and toxicity associated with IVC infusions, determined pre- and post-chemotherapy vitamin C and oxalic acid pharmacokinetic profiles, and monitored objective clinical responses, mood and quality of life. Fourteen patients were enrolled. IVC was safe and generally well tolerated, although some patients experienced transient adverse events during or after IVC infusions. The pre- and post-chemotherapy pharmacokinetic profiles suggested that tissue uptake of vitamin C increases after chemotherapy, with no increase in urinary oxalic acid excretion. Three patients with different types of cancer experienced unexpected transient stable disease, increased energy and functional improvement. CONCLUSIONS: Despite IVC's biological and clinical plausibility, career cancer investigators currently ignore it while integrative cancer therapists use it widely but without reporting the kind of clinical data that is normally gathered in cancer drug development. The present study neither proves nor disproves IVC's value in cancer therapy, but it provides practical information, and indicates a feasible way to evaluate this plausible but unproven therapy in an academic environment that is currently uninterested in it. If carried out in sufficient numbers, simple studies like this one could identify specific clusters of cancer type, chemotherapy regimen and IVC in which exceptional responses occur frequently enough to justify appropriately focused clinical trials. TRIAL REGISTRATION: ClinicalTrials.gov NCT01050621.

Interaction of the bacteria Xenorhabdus nematophila (Enterobactericeae) and Bacillus subtilis (Bacillaceae) with the hemocytes of larval Malacosoma disstria (Insecta: Lepidoptera: Lasiocampidae).

Malacosoma disstria larvae are a pest of deciduous trees. Little is known on the interaction of bacteria with the immediate hemocytic antimicrobial responses of these insects. Incubating dead Xenorhabdus nematophila and Bacillus subtilis with a mixture of serum-free granular cells and plasmatocytes in vitro revealed differential bacterial-hemocyte adhesion and differential discharge of lysozyme and phenoloxidase but not total protein. Although active phenoloxidase adhered equally to both bacterial species, X. nematophila limited enzyme activation whereas B. subtilis enhanced activation. Serum with active phenoloxidase (as opposed to tropolone-inhibited phenoloxidase) and purified insect lysozyme increased bacterial-hemocyte adhesion of both bacterial species. An apolipophorin-III-like protein when incubated with hemocytes, limited their responses to glass slides and bacterial adhesion. However, initial binding of the protein to both bacteria increased granular cell levels with bacteria while lowering the plasmatocyte levels with adhering procaryotes. The protein also increased lysozyme and phenoloxidase activities. Although B. subtilis in vivo elicited a nodulation-based decline in total hemocyte counts and did not affect hemocyte viability, dead X. nematophila elevated hemocyte counts and damaged the hemocytes as lipopolysaccharide levels increased and X. nematophila emerged into the hemolymph. Apolipophorin-III-like protein once bound to the bacteria slowed their removal from the hemolymph.

Protease inhibitor effects on triglyceride synthesis and adipokine secretion in human omental and subcutaneous adipose tissue.

OBJECTIVE: Significant advances in the treatment of the morbidity and mortality associated with AIDS are also associated with undesirable side-effects in fat redistribution (lipodystrophy), insulin resistance and cardiovascular risk, which is directly linked to protease inhibitor (PI) treatment. METHODS: The effects of four different PIs on triglyceride (TG) storage and adipokine production (leptin, adiponectin, and acylation stimulating protein [ASP]) in omental (OM) and subcutaneous (SC) adipose tissues were examined. RESULTS: Initial results demonstrated that saquinivir (SQV) and ritonivir (RTV) had little observed effect on de novo TG synthesis ([3H]glucose incorporation into TG) or fatty acid re-esterification ([14C]oleate incorporation into TG), whereas amprenivir (APV) and indinivir (IDV) reduced TG synthesis, especially in SC tissue up to 30+/-5.8% P<0.05 and 46+/-7.8% P<0.001, at 20 microM, respectively. There was no observed effect on phospholipid synthesis, tissue protein or toxicity. Only APV and IDV decreased leptin and adiponectin secretion in SC tissue, in a time- and concentration-dependent manner: at 18 h, leptin was inhibited by 54+/-3.1% (P<0.001) and 44+/-6.4% (P<0.001) by APV and IDV (40 microM), respectively, and adiponectin was inhibited by 35+/-5.6%(P<0.001) and 25+/-12.3% (P<0.05) by APV and IDV (40 IuM), respectively. By contrast, both IDV and APV decreased ASP secretion in OM tissues by a maximum of 53 +/-7.8% (P<0.001) and 59+/-5.9% (P<0.001), respectively, and by a maximum of 86+/-1.6% (P<0.001) and 72 +/-4% (P<0.001), respectively, in SC tissues. CONCLUSION: PI have a direct effect on human adipose tissue which are site, PI and adipokine specific; these effects may contribute to the overall adipose imbalance and development of lipodystrophy, and metabolic syndrome in HIV-positive individuals.

Bivariate linkage between acylation-stimulating protein and BMI and high-density lipoproteins.

OBJECTIVE: Given the importance of visceral adiposity in the metabolic syndrome, whether levels of adipokines have shared genetic effects (pleiotropy) with aspects of the metabolic syndrome should be addressed. Acylation-stimulating protein (ASP), an adipose-derived protein, influences lipid metabolism, obesity, and glucose use. Therefore, our objective was to examine the genetic regulation of ASP and associated pleiotropic effects. RESEARCH METHODS AND PROCEDURES: We assayed serum ASP levels in 435 Mexican Americans participating in the San Antonio Family Heart Study and performed univariate and bivariate variance components analysis. RESULTS: Additive genetic heritability of ASP was 26% (p = 0.0004). Bivariate genetic analysis detected significant genetic correlations between ASP and several lipid measures but not between ASP and adiposity or diabetes measures. We detected two potential quantitative trait loci influencing ASP levels. The strongest signal was on chromosome 17 near marker D17S1303 [log of the odds ratio (LOD) = 2.7]. The signal on chromosome 15 reached its peak near marker D15S641 (LOD = 2.1). Both signals localize in regions reported to harbor quantitative trait loci influencing obesity and lipid phenotypes in this population. Bivariate linkage analysis yielded LODs of 4.7 for ASP and BMI on chromosome 17 and 3.2 for ASP and high-density lipoprotein2a on chromosome 15. DISCUSSION: Given these findings, there seems to be a significant genetic contribution to variation in circulating levels of ASP and an interesting pattern of genetic correlation (i.e., pleiotropy) with other risk factors associated with the metabolic syndrome.

Fasting acylation-stimulating protein is predictive of postprandial triglyceride clearance.

Postprandial plasma triglyceride (ppTG) and NEFA clearance were stratified by plasma acylation-stimulating protein (ASP) and gender to determine the contribution of fasting ASP in a normal population (70 men; 71 women). In the highest ASP tertile only, ASP decreased over 8 h (90 +/- 9.7 nM to 70 +/- 5.9 nM, P<0.05 males; 61.9 +/- 4.0 nM to 45.6 +/- 6.2 nM, P<0.01 females). Fasting ASP correlated positively with ppTG response. ppTG (P<0.0001, 2-way ANOVA, both genders) and NEFA levels progressively increased from lowest to highest ASP tertile, with the greatest differences in males. By stepwise multiple regression, the best prediction of ppTG was: (fasting ASP + apolipoprotein B + insulin + TG; r=0.806) for men and (fasting ASP + total cholesterol; r=0.574) for women. Leptin, body mass index, and other fasting variables did not improve the prediction. Thus, in men and women, ASP significantly predicted ppTG and NEFA clearance and, based on lower ASP, women may be more ASP sensitive than men. Plasma ASP may be useful as a fasting variable that will provide additional information regarding ppTG and NEFA clearance.

Virulence of Candida albicans mutants toward larval Galleria mellonella (Insecta, Lepidoptera, Galleridae).

Culture medium affected the virulence of a strain of Candida albicans toward Galleria mellonella larvae, but the yeast growth rates in yeast extract - peptone - dextrose broth and synthetic Galleria serum were not correlated with yeast virulence. Virulent C. albicans grew rapidly in larval serum, whereas, it limited nodulation and continued development in vivo, producing toxins that damaged the hemocytes and fat body. Nonpathogenic yeast-phase cells grew slowly in larval serum but induced extensively melanized nodules in vivo and developed no further. There was no discernible relationship in 14 exo-enzymes between the virulent and avirulent yeast strains and virulence. The avirulent myosin-I-defective yeast cells were rapidly removed from the hemolymph in vivo because of lysozyme-mediated yeast agglutination and the possible binding of the yeast cells by lysozyme and apolipophorin-III. Both lysozyme and apolipophorin-III are proteins that bind beta-1,3-glucan. Finally, insects with nonpathogenic C. albicans exhibited induced immunity and were more resistant to candidiasis from the wild-type yeast cells than were noninduced insects.

Kinases, intracellular calcium, and apolipophorin-III influence the adhesion of larval hemocytes of the lepidopterous insect, Galleria mellonella.

Based on the results from the use of selective inhibitors and activators, active protein kinase A, protein tyrosine kinase, and protein kinase C (PKC) isoforms decreased the adhesion of larval Galleria mellonella hemocytes to glass slides. The protein kinase A inhibitor at all concentrations increased granular cell adhesion only whereas protein tyrosine kinase elevated both granular and plasmatocyte attachment at the lowest concentration. Active, Ca(2+)- and lipid-dependent PKC isoforms limited plasmatocyte and granular cell adhesion whereas PKC that was inhibited by selected compounds (with differed modes of PKC inhibition) enhanced hemocyte attachment. The granular cells were more sensitive to the PKC inhibitors than were plasmatocytes. Phospholipase C and its diacylglyceride product were necessary to reduce hemocyte adhesion and maintain PKC activity. Extracellular Ca(2+), possibly transported through L-channels, was required for plasmatocyte attachment. In contrast, lowering the levels of cytosolic Ca(2+) was associated with decreased PKC activity and was required for hemocyte adhesion.

Growth of an ovarian cell line of Galleria mellonella and its response to immune-inducing factors.

Antibacterial proteins are produced in the reproductive tracts of some insect species. The advent of a pupal ovarian cell line of the lepidopteran Galleria mellonella offered an opportunity for exploring the use of ovarian tissue culture to induce antimicrobial proteins in lieu of the larvae. The ovarian cell growth rates and cell yields were maximized by adjusting Grace's medium to pH 6.5, adding 15% (v/v) qualified heat-inactivated fetal calf serum, and lowering the sucrose concentration to 9.3 g/L. Five cell forms and biochemical profiles of the collective cell types were analyzed throughout the culture growth cycle. The final modified culture medium did not affect morphogenesis, whereas it increased the culture growth rate by 50% and the final cell yield threefold. The molting and immunoprotein-inducing hormone, 20-hydroxyecdysone, increased culture growth rate and altered the levels of cell types A and D. Neither 20-hydroxyecdysone nor the larval immunizing agents, apolipophorin-III or Bacillus subtilis, in combination or alone, induced antibacterial activity. The bacterium did induce immunity in both larval and adult stages.

Apolipophorin-III affects the activity of the haemocytes of Galleria mellonella larvae.

Apolipophorin-III (apoLp-III) impaired the adhesion of plasmatocytes and a granular cell-subpopulation of larval Galleria mellonella to glass slides. The protein bound to haemocytes, limited the responses of the plasmatocytes to Bacillus subtilis and increased the percentage of a subgroup of granular cells with adhering bacteria. The total number of bacteria adhering to all the haemocytes on the slides declined. Injections of apoLp-III slowed bacterial removal from the haemolymph without affecting total haemocyte counts and impaired haemocyte attachment to glass slides. Purified apoLp-III bound to B. subtilis. ApoLp-III in serum bound to bacteria within 5 min, peaked at 15 min and was either shed or dissociated by 60 min. ApoLp-III bound to B. subtilis lowered the adhesion of the bacteria to the haemocytes and slowed the removal of the bacteria from the haemolymph.