Near-infrared light-responsive inorganic nanoparticles have been shown to enhance the efficacy of cancer photothermal ablation therapy. However, current nanoparticle-mediated photothermal ablation is more effective in treating local cancer at the primary site than metastatic cancer. Here, we report the design of a near-infrared light-induced transformative nanoparticle platform that combines photothermal ablation with immunotherapy. The design is based on chitosan-coated hollow CuS nanoparticles that assemble the immunoadjuvants oligodeoxynucleotides containing the cytosine-guanine (CpG) motifs. Interestingly, these structures break down after laser excitation, reassemble, and transform into polymer complexes that improve tumor retention of the immunotherapy. In this “photothermal immunotherapy” approach, photothermal ablation-induced tumor cell death reduces tumor growth and releases tumor antigens into the surrounding milieu, while the immunoadjuvants potentiate host antitumor immunity. Our results indicated that combined photothermal immunotherapy is more effective than either immunotherapy or photothermal therapy alone against primary treated and distant untreated tumors in a mouse breast cancer model. These hollow CuS nanoparticles are biodegradable and can be eliminated from the body after laser excitation.

Oseltamivir is the main medicine recommended by the World Health Organization in anticipation of next influenza pandemic. This anti-influenza viral agent is an ester prodrug, and the antiviral activity is achieved by its hydrolytic metabolite: oseltamivir carboxylate. In this study, we report that the hydrolytic activation is catalyzed by carboxylesterase human carboxylesterase (HCE) 1. Liver microsomes rapidly hydrolyzed oseltamivir, but no hydrolysis was detected with intestinal microsomes or plasma. The overall rate of the hydrolysis varied among individual liver samples and was correlated well with the level of HCE1. Recombinant HCE1 but not HCE2 hydrolyzed this prodrug and produced similar kinetic parameters as the liver microsomes. Several HCE1 natural variants differed from the wildtype enzyme on the hydrolysis of oseltamivir. In the presence of antiplatelet agent clopidogrel, the hydrolysis of oseltamivir was inhibited by as much as 90%

Aspirin (acetylsalicylic acid) and clopidogrel are two major antithrombogenic agents that are widely used for the treatment and prevention of cerebro-and cardiovascular conditions such as stroke. Combined use produces enhanced therapeutic effect. Aspirin and clopidogrel both are esters, and hydrolysis leads to decreased or inactivated therapeutic activity. The aim of the study was to determine whether aspirin and clopidogrel are hydrolyzed by the same enzyme(s), thus reciprocally prolonging the antithrombogenic activity. To test this possibility, microsomes from the liver and intestine were assayed for the hydrolysis of aspirin and clopidogrel. In contrary to the hypothesis, aspirin and clopidogrel were hydrolyzed in a tissue-differential manner. Liver microsomes hydrolyzed both drugs, whereas intestinal microsomes hydrolyzed aspirin only. Consistent with the tissue distribution of two carboxylesterases human carboxylesterase (HCE) 1 and HCE2, recombinant HCE1 hydrolyzed clopidogrel, whereas recombinant HCE2 hydrolyzed aspirin. In addition, hydrolysis of clopidogrel among liver samples was correlated well with the level of HCE1, and hydrolysis of aspirin with HCE2. Certain natural variants differed from the wild-type enzymes on the hydrolysis of aspirin or clopidogrel. In the presence of ethyl alcohol, clopidogrel is converted to ethyl clopidogrel. Carboxylesterases are important pharmacological determinants for drugs containing ester linkages and exhibit a large interindividual variation. The isoform-specific hydrolysis of aspirin and clopidogrel suggests that these two antithrombogenic agents may have pharmacokinetic interactions with different sets of ester drugs, and the altered hydrolysis by polymorphic mutants provides a molecular explanation to the interindividual variation.

The basic helix-loop-helix (bHLH) proteins are intimately associated with developmental events such as cell differentiation and lineage commitment. The HLH domain in the bHLH motif is responsible for dimerization, whereas the basic region mediates DNA binding. Based on sequence alignment and domain analysis, differentially expressed in chondrocytes/stimulated with retinoic acid/split and hairy-related proteins (DEC/STRA/SHARPs) represent a new class of bHLH proteins. The present study describes the functional characterization of DEC1. Subtractive experiments and blotting analyses demonstrated that DEC1 was highly expressed in colon carcinomas, but not in the adjacent normal tissues. Several cell cycle blockers markedly induced DEC1 expression. Stable transfectants with a tetracycline-inducible construct demonstrated that DEC1 caused proliferation inhibition, antagonized serum deprivation-induced apoptosis and selectively inhibited the activation of procaspases. These activities were highly correlated with the abundance of tetracycline-induced DEC1. Stable transfectants expressing a mutant DEC1 (lacking the DNA-binding domain) exhibited neither proliferation inhibition nor apoptotic antagonism, which suggests that DNA binding is required for these actions. Enzymic assays and immunoblotting analyses demonstrated that induction of DEC1 by tetracycline significantly decreased the activation of procaspases 3, 7 and 9 but not procaspase 8. The selective suppression on the activation of procaspases 3, 7 and 9 over procaspase 8 suggests that DEC1-mediated anti-apoptosis is achieved by blocking apoptotic pathways initiated via the mitochondria. The results functionally distinguish DEC1 from other bHLH proteins and directly link this factor to oncogenesis.

Carboxylesterases hydrolyze chemicals containing such functional groups as a carboxylic acid ester, amide and thioester. The liver contains the highest carboxylesterase activity and expresses two major carboxylesterases: HCE1 and HCE2. In this study, we analyzed 104 individual liver samples for the expression patterns of both carboxylesterases. These samples were divided into three age groups: adults (≥ 18 years of age), children (0 days-10 years) and fetuses (82-224 gestation days). In general, the adult group expressed significantly higher HCE1 and HCE2 than the child group, which expressed significantly higher than the fetal group. The age-related expression was confirmed by RT-qPCR and Western immunoblotting. To determine whether the expression patterns reflected the hydrolytic activity, liver microsomes were pooled from each group and tested for the hydrolysis of drugs such as oseltamivir and insecticides such as deltamethrin. Consistent with the expression patterns, adult microsomes were ∼4 times as active as child microsomes and 10 times as active as fetal microsomes in hydrolyzing these chemicals. Within the same age group, particularly in the fetal and child groups, a large inter-individual variability was detected in mRNA (430 fold), protein (100 fold) and hydrolytic activity (127 fold). Carboxylesterases are recognized to play critical roles in drug metabolism and insecticide detoxication. The findings on the large variability among different age groups or even within the same age group have important pharmacological and toxicological implications, particularly in relation to pharmacokinetic alterations of ester drugs in children and vulnerability of fetuses and children to pyrethroid insecticides.

Human differentially expressed in chondrocytes (DEC), mouse stimulated with retinoic acid and rat split and hairy related proteins constitute a structurally distinct class of the basic helix-loop-helix proteins. DEC1 is abundantly expressed in tumors and protects against apoptosis induced by serum starvation. In this study, we report that DEC1 antiapoptosis is achieved by inducing survivin, an antiapoptotic protein. In paired tumor-normal tissues, survivin and DEC1 exhibited a paralleled expression pattern. Tetracycline-induced expression of DEC1 in stable lines proportionally increased the expression of survivin. In reporter assays, DEC1 transactivated the survivin promoter but repressed the DEC2 promoter. In contrast to the repression, the activation was delayed and varied depending on serum concentrations and cycle blockers. Studies with reporter mutants located, in the survivin promoter, two Sp1 sites that supported DEC1 transactivation. Electrophoretic mobility shift assay and chromatin immunoprecipitation detected the presence of DEC1 in the survivin promoter. These findings establish that the survivin gene is a transcription target of DEC1, and induction of survivin is at least in part responsible for DEC1 antiapoptosis.

ABSTRACT:Carboxylesterases hydrolyze numerous endogenous and foreign compounds with diverse structures. Humans and rodents express multiple forms of carboxylesterases, which share a high degree of sequence identity (ϳ70%). Alignment analyses locate in carboxylesterases several functional subsites such the catalytic triad as seen in acetylcholinesterase. The aim of this study was to determine among human and rodent carboxylesterases the immunorelatedness, overlapping substrate specificity, differential sensitivity to serine enzyme inhibitors, tissue distribution, and tumor-related expression. Six antibodies against whole carboxylesterases or synthetic peptides were tested for their reactivity toward 11 human or rodent recombinant carboxylesterases. The antibodies against whole proteins generally exhibited a broader cross-reactivity than the anti-peptide antibodies. All carboxylesterases hydrolyzed para-nitrophenylacetate and para-nitrophenylbutyrate. However, the relative activity varied markedly from enzyme to enzyme (>20-fold), and some carboxylesterases showed a clear substrate preference. Carboxylesterases with the same functional subsites had a similar profile on substrate specificity and sensitivity toward phenylmethylsulfonyl fluoride (PMSF) and paraoxon, suggesting that these subsites play determinant roles in the recognition of substrates and inhibitors. Among three human carboxylesterases, HCE-1 hydrolyzed both substrates to a similar extent, whereas HCE-2 and HCE-3 showed an opposite substrate preference. All three enzymes were inhibited by PMSF and paraoxon, but they showed a marked difference in relative sensitivities. Based on immunoblotting analyses, HCE-1 was present in all tissues examined, whereas HCE-2 and HCE-3 were expressed in a tissue-restricted pattern. Colon carcinomas expressed slightly higher levels of HCE-1 and HCE-2 than the adjacent normal tissues, whereas the opposite was true with HCE-3.

Medullary carcinoma of the colon is a unique histologic subtype of microsatellite unstable colorectal carcinoma but little is known regarding its tumor-immunoregulatory microenvironment. The aims of this study were to characterize the immune environment of medullary carcinoma and compare it with other microsatellite unstable and microsatellite stable colorectal carcinomas. An initial gene expression microarray analysis of six cases of medullary carcinoma was used to detect potentially differentially expressed genes. We extended this analysis utilizing genomic data from the Cancer Genome Atlas to compare eight cases of medullary carcinoma with other microsatellite unstable and stable carcinomas. Finally, we evaluated expression of key immune pathway proteins and lymphocyte subsets via immunohistochemistry of a large group of medullary carcinomas (n = 105) and compared these findings with three other groups: poorly differentiated, microsatellite unstable well-differentiated and microsatellite stable well-differentiated carcinomas. Microarray and the Cancer Genome Atlas data analysis identified significant upregulation of several immunoregulatory genes induced by IFNγ including IDO-1, WARS (tRNA(trp)), GBP1, GBP4, GBP5, PDCD1 (PD-1), and CD274 (PD-L1) in medullary carcinoma compared with other microsatellite unstable and microsatellite stable tumors. By immunohistochemistry, IDO-1 was expressed in 64% of medullary carcinomas compared with 19% (9/47) of poorly differentiated carcinomas, 14% (3/22) of microsatellite unstable, and 7% (2/30) of the microsatellite stable well-differentiated carcinomas (Po 0.0001). tRNA(trp) was overexpressed in 81% (84/104) of medullary carcinomas, 19% (9/47) of poorly differentiated, 32% (7/22) of microsatellite unstable, and 3% (1/30) of microsatellite stable well-differentiated carcinomas (Po 0.0001). Medullary carcinoma had higher mean CD8+ and PD-L1+ tumor-infiltrating lymphocytes compared with all other groups (P o0.0001). This study demonstrates overexpression of several immunoregulatory genes in microsatellite unstable colorectal carcinomas and that expression of these genes and proteins is more prevalent in the medullary carcinoma subtype, which may be of use both diagnostically and therapeutically.