Pharmacological PI3K inhibition in head and neck squamous cell carcinoma: A systematic review

BACKGROUND

This systematic review aimed to investigate the in vitro and in vivo effects of phosphatidylinositol-3-kinase (PI3K) inhibitors on head and neck squamous cell carcinoma (HNSCC). Considering the role of PI3K and its downstream effectors in cell proliferation, invasion, and survival, it is reasonable to expect that treatment with PI3K inhibitors could control HNSCC onset and progression. Thus, the research question for our review was whether pharmacological inhibition of PI3K affects HNSCC progression.

METHODS

In vitro and in vivo studies were selected from six databases. We collected data regarding cell viability, apoptosis, and the regulation of protein expression levels from in vitro studies. For the in vivo studies, we analyzed the reduction in tumor size or gene and protein expression.

RESULTS

The included studies showed reduced cell proliferation and apoptosis after treatment with PI3K inhibitors. PI3K inhibitors in combination with other drugs had an enhanced anticancer effects compared to those of single-drug treatments.

CONCLUSIONS

The results support the potential of PI3K inhibitors as candidates for clinical trials in HNSCC.

Distinct ability to accumulate eosinophils during the inflammatory cellular response to M. bovis BCG in the mouse pleural cavity

OBJECTIVE AND DESIGN

The host response to Mycobacteria focuses on the development of cell-mediated immunity and granuloma formation. Here, we investigated the onset of cellular responses to mycobacteria in murine pleurisy.

MATERIAL

Distinct mouse strains previously described as Bcg susceptible or resistant were inoculated intrathoracically with different doses of live M. bovis BCG.

METHODS

At various time intervals, cells harvested from the inflammatory site were identified and ultra-structurally analysed.

RESULTS

BCG-induced pleurisy had two peaks of cellular influx at 1 and 15 days after infection. At the first half hour, macrophages were found to be heavily infected. Neutrophil arrival started after 2 h of infection and peaked at 4 h. At this time, neutrophils were found ingesting mycobacteria exclusively with a high infecting dose. BCG was potently more eosinophilotactic in Bcg susceptible mice than in the resistant ones and to other well known eosinophilia inducers: IL-5, PAF-acether or LPS.

CONCLUSIONS

Mycobacterial load and mouse susceptibility seem to determine the early granulocyte dynamics in the lesion.

Opposite effects of M. leprae or M. bovis BCG delipidation on cellular accumulation into mouse pleural cavity. Distinct accomplishment of mycobacterial lipids in vivo

OBJECTIVES AND DESIGN

The effect of mycobacterial lipids on the onset of the early acute inflammatory response in BALB/c mice pleurisy was investigated.

MATERIALS AND METHODS

Intact Mycobacterium leprae and Mycobacterium bovis BCG (BCG), their lipids, and delipidated mycobacteria were used to evaluate total leukocytes and cell types migrated to the pleural cavity (8 animals/experimental group).

RESULTS

BCG Moreau (x10(-6)/cavity), delipidated BCG and its lipids gradually recruited cells leading to arrival, respectively, of neutrophils (7.8+/-1.9, 4.7+/-0.9, 1.8+/-0.25) followed by mononuclear cells (4.8+/-0.8, 3.7+/-0.7, 2.45+/-0.22) and eosinophils (0.39+/-0.08, 0.32+/-0.11, 0.41+/-0.65). BCG delipidation decreased the number of migrated total leukocytes (ANOVA, and Newman-Keuls-Student-test), whereas M. leprae delipidation accumulated neutrophils (0.85+/-0.01) and eosinophils (1.65+/-0.18).

CONCLUSIONS

Intact M. leprae and its lipids did not incite any cell recruitment. Apolar external cell wall lipids from M. leprae and BCG induce different cellular responses. They seem to have a crucial importance at the first contact of mycobacteria with the host cell, modulating the influx of neutrophils/macrophages in the early (4/24 h) onset of the inflammatory reaction.

Opposite cellular accumulation and nitric oxide production in vivo after pleural immunization with M. leprae or M. bovis BCG

Mycobacteria as intracellular pathogens have evolved mechanisms to survive within macrophages. Our previous data showed that M. leprae (ML), unlike M. bovis BCG, did not induce an inflammatory response in the mice subcutaneous tissue. Further, ML inhibited BCG-induced foot pad oedema and seemed to transform macrophages in epithelioid cells. Since these mycobacteria share common antigens, here we seeked to compare the acute and chronic cellular response evoked by ML and BCG in pleurisy of a mycobacteria-susceptible mice (BALB/c). The total leukocytes, the cell type that migrated to the pleural cavity and macrophage activation assayed by nitric oxide release were determined. Live or dead BCG Moreau recruited the same extent of cells, essentially monocytes and neutrophils, dose-dependently, in both acute and chronic pleurisy. BCG-induced eosinophilia was observed only in the acute response (after 24 h of injection). A significant nitric oxide release by pleural macrophages was triggered by BCG Moreau without previous activation. Nevertheless, ML failed to recruit leukocytes to the pleural space or to lead to nitric oxide production despite the number of bacilli used and the time studied (1, 7 or 14 days after injection). Although these mycobacteria have common antigens that cross-react, these data show a distinct ability of ML or BCG to recruit cells to the pleural space and to activate pleural macrophage for nitric oxide production in vivo.

Lipids from Mycobacterium leprae cell wall suppress T-cell activation in vivo and in vitro

The influence of Mycobacterium leprae cell wall lipids on lymphocyte functions has been investigated in vivo (delayed-type hypersensitivity) and in vitro. The inflammatory response has been earlier evaluated by the mouse footpad oedema model and the delipidated mycobacteria evoked a mild but significant inflammatory response. Herein a higher level of hypersensitivity reaction was observed with delipidated bacilli than with the intact mycobacteria. The lipids obtained from the extract of M. leprae external cell wall were used to prepare liposomes, which have not been shown to be toxic to lymphocytes. The method of lipidic extraction and the sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the lipid fraction did not reveal any trace of proteins. Thin-layer chromatography of this extract detected four different bands with an apolar character, suggestive of mycolic and fatty acids. These same M. leprae liposomes potently suppressed lymph node cells, as well CD4+ and CD8+ T-cell lines, and an antigen-specific T-cell clone (T 4-9) proliferation, even under potent stimulus. Cholesterol-choline liposomes, unrelated to M. leprae liposomes, used as a control in the biological assays showed no significant effect on lymphoblastic activity, which points to the specificity of M. leprae lipids. These data demonstrated that M. leprae cell wall lipids induce immune suppression in mice without causing any membrane alteration in T cells as assessed throughout kinetic studies in vitro. This fact is closely related to the down-regulating effect induced by M. leprae lipids which we have previously observed in macrophage functions in vivo and in vitro. Although this lipidic fraction showed a suppressive action on T lymphocytes in vitro (proliferation) and in vivo (delayed-type hypersensitivity), its possible significance in the establishment of a specific immune response to M. leprae must be further investigated.

Down-regulatory effect of Mycobacterium leprae cell wall lipids on phagocytosis, oxidative respiratory burst and tumour cell killing by mouse bone marrow derived macrophages

The authors have previously demonstrated that lipids from Mycobacterium leprae cell walls inhibit macrophage functions and are endowed with anti-inflammatory properties in vivo. To investigate these observations further, the authors describe here the influence of dead M. leprae or of the lipids extracted from the cell wall of the mycobacterium, enclosed in liposomes, on the phagocytic, oxidative respiratory burst and tumouricidal ability of bone marrow derived macrophages in vitro. Dead M. leprae or its cell wall lipids abrogated the oxidative respiratory burst and phagocytic ability of mouse bone marrow derived macrophages. A dose-dependent inhibitory effect of the bacterial lipid extract on tumour cell killing by lipopolysaccharide (LPS)-activated bone marrow derived macrophages was demonstrated. However, when delipidated M. leprae was added to cultures of bone marrow derived macrophages, immune phagocytosis and superoxide production was up-regulated. Mycobacterium leprae or its lipids did not appear to be toxic to those cells assayed by the MTT (methyl thiazol tetrazolium) test. These data, added to our preceding observations, support the hypothesis that the down-regulatory activity of M. leprae wall lipids on macrophage function might be one of the evasive mechanisms of the bacterium to enable it to perpetuate itself in the host tissues.

Lipids from Mycobacterium leprae cell wall are endowed with an anti-inflammatory property and inhibit macrophage function in vivo

In general, the majority of bacteria are pre-inflammatory when injected in experimental animals. However, Mycobacterium leprae has no inflammatory effect when injected into mouse footpad, but using the delipidated mycobacteria we observed a mild significant increase in footpad oedema. Other mycobacteria, Mycobacterium bovis-BCG or M. tuberculosis induce a strong paw oedema. Furthermore, M. leprae reduced locally the BCG-induced inflammatory reaction in mouse footpad, whereas delipidated M. leprae did not influence this reaction. Both M. leprae and M. leprae cell wall lipids blocked immune phagocytosis in vivo by inflammatory macrophages (from an induced focus). In contrast delipidated M. leprae stimulated the phagocytosis reaction. Neither intact M. leprae. delipidated M. leprae, nor its lipids had any toxic effect on macrophages or on cell migration. Although M. leprae did not interfere on cell influx and cell type in an induced-inflammatory site, this mycobacterium led to the appearance of a distinct cell population in vivo. The hypothesis is that M. leprae would transform macrophages in epithelioid cells, suggested by morphology analysis of cells by fluorescence-activated cell sorter and observed under optic microscopy.

[Automated analysis of cardiotocographic signals]

Cardiotocographic signals, used as a perinatal diagnostic tool, comprise fetal heart beat signals (FHR), uterine contractions (UC) and fetal movements (FM). Visual inspection of these three signals is limited, subjective, time consuming and with low reproducibility. The present paper illustrates an application of signal processing techniques to the automatic analysis of cardiotocographic signals, allowing to overcome visual inspection limitations. Porto system of cardiotocograms automatic analysis acquires the signals from a conventional cardiotocograph. The signals are stored and processed by a personal computer. System software allows the user to perform several operations such as signal acquisition, signal storage and retrieval from files, signal analysis and display. Signal analysis is preceded by various signal conditioning operations (filtering, spike removal, etc.) and consists in the estimation of several parameters with diagnostic value: FHR baseline; FHR accelerations and decelerations; uterine contractions; long and short term FHR variability. The system prototype is working on a routine basis at the Obstetrics Department of S. João Hospital (main Oporto Hospital) and is being evaluated using a large data set. A preliminary evaluation performed by 3 experts on a 50 cases set, yielded an agreement rate with computer measurements of 98% for the baseline, 72% to 82% for accelerations and decelerations and 76% for the uterine contractions.