Tumor-derived GCSF Alters Tumor and Systemic Immune System Cell Subset Composition and Signaling

While immunotherapies such as immune checkpoint blockade and adoptive T-cell therapy improve survival for a subset of human malignancies, many patients fail to respond. Phagocytes including dendritic cells (DC), monocytes, and macrophages (MF) orchestrate innate and adaptive immune responses against tumors. However, tumor-derived factors may limit immunotherapy effectiveness by altering phagocyte signal transduction, development, and activity. Using Cytometry by Time-of-Flight, we found that tumor-derived GCSF altered myeloid cell distribution both locally and systemically. We distinguished a large number of GCSF-induced immune cell subset and signal transduction pathway perturbations in tumor-bearing mice, including a prominent increase in immature neutrophil/myeloid-derived suppressor cell (Neut/MDSC) subsets and tumor-resident PD-L1⁺ Neut/MDSCs. GCSF expression was also linked to distinct tumor-associated MF populations, decreased conventional DCs, and splenomegaly characterized by increased splenic progenitors with diminished DC differentiation potential. GCSF-dependent dysregulation of DC development was recapitulated in bone marrow cultures in vitro, using medium derived from GCSF-expressing tumor cell cultures. Importantly, tumor-derived GCSF impaired T-cell adoptive cell therapy effectiveness and was associated with increased tumor volume and diminished survival of mice with mammary cancer. Treatment with neutralizing anti-GCSF antibodies reduced colonic and circulatory Neut/MDSCs, normalized colonic immune cell composition and diminished tumor burden in a spontaneous model of mouse colon cancer. Analysis of human colorectal cancer patient gene expression data revealed a significant correlation between survival and low GCSF and Neut/MDSC gene expression. Our data suggest that normalizing GCSF bioactivity may improve immunotherapy in cancers associated with GCSF overexpression.

Significance

Tumor-derived GCSF leads to systemic immune population changes. GCSF blockade restores immune populations, improves immunotherapy, and reduces tumor size, paralleling human colorectal cancer data. GCSF inhibition may synergize with current immunotherapies to treat GCSF-secreting tumors.

In vitro glucuronidation of the antibacterial triclocarban and its oxidative metabolites

Triclocarban (3,4,4'-trichlorocarbanilide; TCC) is widely used as an antibacterial in bar soaps. During use of these soaps, a significant portion of TCC is absorbed by humans. For the elimination from the body, glucuronidation plays a key role in both biliary and renal clearance. To investigate this metabolic pathway, we performed microsomal incubations of TCC and its hydroxylated metabolites 2'-OH-TCC, 3'-OH-TCC, and 6-OH-TCC. Using a new liquid chromatography-UV-mass spectrometry method, we could show a rapid glucuronidation for all OH-TCCs by the uridine-5'-diphosphate-glucuronosyltransferases (UGT) present in liver microsomes of humans (HLM), cynomolgus monkeys (CLM), rats (RLM), and mice (MLM). Among the tested human UGT isoforms, UGT1A7, UGT1A8, and UGT1A9 showed the highest activity for the conjugation of hydroxylated TCC metabolites followed by UGT1A1, UGT1A3, and UGT1A10. Due to this broad pattern of active UGTs, OH-TCCs can be efficiently glucuronidated in various tissues, as shown for microsomes from human kidney (HKM) and intestine (HIM). The major renal metabolites in humans, TCC-N-glucuronide and TCC-N'-glucuronide, were formed at very low conversion rates (<1%) by microsomal incubations. Low amounts of N-glucuronides were generated by HLM, HIM, and HKM, as well as by MLM and CLM, but not by RLM, according to the observed species specificity of this metabolic pathway. Among the human UGT isoforms, only UGT1A9 had activity for the N-glucuronidation of TCC. These results present an anomaly where in vivo the predominant urinary metabolites of TCC are N and N'-glucuronides, but these compounds are slowly produced in vitro.

Variable-number tandem repeats that are useful in genotyping isolates of Salmonella enterica subsp. enterica serovars Typhimurium and Newport

The genome of Salmonella enterica subsp. enterica serovar Typhimurium strain LT2 was analyzed for direct repeats, and 54 sequences containing variable-number tandem repeat loci were identified. Ten primer pairs that anneal upstream and downstream of each selected locus were designed and used to amplify PCR targets in isolates of S. enterica serovars Typhimurium and Newport. Four of the 10 loci did not show polymorphism in the length of products. Six loci were selected for analysis. Isolates of S. enterica serovars Typhimurium and Newport that were related to specific outbreaks and showed identical pulsed-field gel electrophoresis patterns were indistinguishable by the length of the six variable-number tandem repeats. Isolates that differed in their pulsed-field gel electrophoresis patterns showed polymorphism in variable-number tandem repeat profiles. Length of the products was confirmed by DNA sequence analysis. Only 2 of the 10 loci contained exact integers of the direct repeat. Eight loci contained partial copies. The partial copies were maintained at the ends of the variable-number tandem repeat loci in all isolates. In spite of having partial copies that were maintained in all isolates, the number of direct repeats at a locus was polymorphic. Six variable-number tandem repeat loci were useful in distinguishing isolates of S. enterica serovars Typhimurium and Newport that had different pulsed-field gel electrophoresis patterns and in identifying outbreak-associated cases that shared a common pulsed-field gel pattern.

Interaction studies on proteins encoded by the phthiocerol dimycocerosate locus of Mycobacterium tuberculosis

Polyketide synthases (PKSs) of Mycobacterium tuberculosis are increasingly being seen as producers of virulence factors that are important for pathogenesis by the bacterium. Thus, the phenolphthiocerol synthase PKS cluster of M. tuberculosis is responsible, in part, for the synthesis of a virulence determinant called phthiocerol dimycocerosate (PDIM). Here, we provide evidence that the PpsE protein, which is part of that cluster, interacts with the type II thioesterase TesA of M. tuberculosis. The interaction was demonstrated by employing a two-hybrid system, and confirmed using a GST (glutathione S-transferase) pull-down' assay after both proteins had been purified to homogeneity. Based on the present findings, a revised model for the processing of polyketides during the synthesis of PDIM is presented.

Molecular basis of Celmer's rules: role of the ketosynthase domain in epimerisation and demonstration that ketoreductase domains can have altered product specificity with unnatural substrates

BACKGROUND

Polyketides are structurally diverse natural products with a range of medically useful activities. Non-aromatic bacterial polyketides are synthesised on modular polyketide synthase multienzymes (PKSs) in which each cycle of chain extension requires a different 'module' of enzymatic activities. Attempts to design and construct modular PKSs that synthesise specified novel polyketides provide a particularly stringent test of our understanding of PKS structure and function.

RESULTS

We show that the ketoreductase (KR) domains of modules 5 and 6 of the erythromycin PKS, housed in the multienzyme subunit DEBS3, exert an unexpectedly low level of stereochemical control in reducing the keto group of a synthetic analogue of the diketide intermediate. This led us to construct a hybrid triketide synthase based on DEBS3 with ketosynthase domain ketosynthase (KS)5 replaced by the loading module and KS1. The construct in vivo produced two major triketide stereoisomers, one expected and one surprising. The latter was of opposite configuration at three out of the four chiral centres: the branching alkyl centre was that produced by KS1 and, surprisingly, both hydroxyl centres produced by the reduction steps carried out by KR5 and KR6 respectively.

CONCLUSIONS

These results demonstrate that the epimerising activity associated with module 1 of the erythromycin PKS can be conferred on module 5 merely by transfer of the KS1 domain. Moreover, the normally precise stereochemical control observed in modular PKSs is lost when KR5 and KR6 are challenged by an unfamiliar substrate, which is much smaller than their natural substrates. This observation demonstrates that the stereochemistry of ketoreduction is not necessarily invariant for a given KR domain and underlines the need for mechanistic understanding in designing genetically engineered PKSs to produce novel products.

Cyanurate mimics of hydrogen-bonding patterns of nucleic bases: crystal structure of a 1:1 molecular complex of 9-ethyladenine and N-methylcyanuric acid

[figure: see text] 9-Ethyladenine forms a unique molecular complex with N-methylcyanuric acid consisting of homomeric and heteromeric hydrogen-bonding patterns. Also, the homomeric hydrogen bond pattern is different than that observed in its pure crystal structures.

Knowledge-based design of bimodular and trimodular polyketide synthases based on domain and module swaps: a route to simple statin analogues

BACKGROUND

Polyketides are structurally diverse natural products that have a range of medically useful activities. Nonaromatic bacterial polyketides are synthesised on modular polyketide synthase (PKS) multienzymes, in which each cycle of chain extension requires a different 'module' of enzymatic activities. Attempts to design and construct modular PKSs that synthesise specified novel polyketides provide a particularly stringent test of our understanding of PKS structure and function.

RESULTS

We have constructed bimodular and trimodular PKSs based on DEBS1-TE, a derivative of the erythromycin PKS that contains only modules 1 and 2 and a thioesterase (TE), by substituting multiple domains with appropriate counterparts derived from the rapamycin PKS. Hybrid PKSs were obtained that synthesised the predicted target triketide lactones, which are simple analogues of cholesterol-lowering statins. In constructing intermodular fusions, whether between modules in the same or in different proteins, it was found advantageous to preserve intact the acyl carrier protein-ketosynthase (ACP-KS) didomain that spans the junction between successive modules.

CONCLUSIONS

Relatively simple considerations govern the construction of functional hybrid PKSs. Fusion sites should be chosen either in the surface-accessible linker regions between enzymatic domains, as previously revealed, or just inside the conserved margins of domains. The interaction of an ACP domain with the adjacent KS domain, whether on the same polyketide or not, is of particular importance, both through conservation of appropriate protein-protein interactions, and through optimising molecular recognition of the altered polyketide chain in the key transfer of the acyl chain from the ACP of one module to the KS of the downstream module.

Laryngeal preservation by treatment with induction chemotherapy and radiotherapy protocol for stage III & IV carcinoma larynx--results of a pilot study

Total laryngectomy for advanced carcinoma of the larynx is effective but functionally disabling. In an effort at laryngeal preservation, 33 patients of stage III/IV carcinoma larynx were treated between 1987 and 1991 with induction chemotherapy followed by definitive radiation. Two chemotherapy protocols were administered. Group I patients received one to three cycles of cisplatin 100 mg/m2 (day 1), bleomycin 15 U/m2 (day 1), and 5-fluorouracil 1000 mg/m2/day (day 2 to 5) at three weekly intervals. This was then followed by radiotherapy. Group II received one to six weekly injections of single agent methotrexate 50 mg/m2 with or without leucocovorin rescue followed by radiotherapy. Any recurrence was salvaged by surgery. Midway through the study, Group II protocol was discontinued as the initial results were not comparable with Group I or standard treatment. The Group I protocol, however, yielded an initial locoregional control rate of 83.3 per cent With the addition of surgical salvage the locoregional control rate was 94.4 per cent and the control rate with laryngeal preservation was 88.8 per cent. The Kaplan-Meier probability of two years and five years disease-free survival was 81.9 per cent and 61.4 per cent respectively. For disease-free survival with laryngeal preservation the corresponding figures for two years and five years were 58.3 per cent and 41.7 per cent. The control group of 51 patients treated with radical surgery followed by radiotherapy yielded survival figures at two years and five years of 64.3 per cent and 57.2 per cent. The difference in the survival of Group I and the control group was not statistically significant (p value = 0.280). These initial results indicate that for stage III and for surgically resectable stage IV laryngeal carcinomas, a protocol of induction combination chemotherapy consisting of cisplatin, bleomycin and 5-fluorouracil followed by radiotherapy and combined with surgical salvage whenever required, can lead to comparable cure rates. In addition, a large proportion of patients are spared the morbidity of a total laryngectomy.

Panic disorder: a different perspective

Panic disorder is a chronic and debilitating illness. In this article, we present an algorithm of the diagnosis and treatment of the illness. We place much importance upon the patient variables associated with the treatment decisions. We emphasize strong patient involvement in treatment as a way to become panic free and improve level of functioning. Panic disorder is defined in DSM-IV1 as "The presence of recurrent panic attacks followed by at least one month of persistent concern about having another panic attack, worry about the possible implications or consequences of the panic attack, or a significant behavioral change related to the attacks." A panic attack is defined as "a discrete period of intense fear or discomfort, in which four or more of the following symptoms developed abruptly and reached a peak within 10 minutes." 1) Palpitations, pounding heart or accelerated heart rate; 2) sweating; 3) trembling or shaking; 4) sensations of shortness of breath or smothering; 5) feeling of choking; 6) chest pain or discomfort; 7) nausea or abdominal distress; 8) feeling dizzy, unsteady, light-headed or faint; 9) derealization or depersonalization; 10) fear of losing control or going crazy; 11) fear of dying; 12) paresthesias; 13) chills or hot flashes. The following hypotheses have been used to conceptualize panic disorder from a psychiatrist's perspective.

Strongyloides stercoralis infection in AIDS

Strongyloides stercoralis infection in humans continues to be a subject that has frequently inspired reviews and papers. Within the AIDS epidemic, interest gathered momentum with the inclusion of this infection in the indicator diseases list, and its subsequent removal 5 years later by the CDC. These actions have prompted a debate as to whether this infection has special significance in patients with AIDS and whether its exclusion from the CDC criteria is justified. A detailed review of the world literature reveals an increased awareness and diagnosis of this infection in patients with AIDS which takes the form of dissemination, a rapid course, and a usually fatal outcome.