Modulation of cell proliferation and differentiation of human lung carcinoma cells by the interferon-alpha.

Treatments of non-small cell lung cancer (NSCLC), the most common form of lung cancer, still remain poor. Interferon alpha (IFN-alpha), an important physiological immunomodulator, possesses direct cytotoxic and cytostatic effects on tumour cells, antiangiogenic effects, and activates anti-tumour immunity. Recently, the IFN-alpha oncologic indications have included melanoma, renal carcinoma, and different types of leukaemia. However, the application of IFN-alpha in therapy of lung cancer has not been validated yet. Herein the human lung carcinoma cell line A549, a model of NSCLC in vitro, was used to pursue the effect of IFN-alpha on A549 cell proliferation and differentiation together with the effect on protein expression and activity of three ATP-transporters mediating multi-drug resistance (MDR). IFN-alpha significantly inhibited the proliferation of A549 cells which was not connected with arrest in a particular cell cycle phase. Further, IFN-alpha-mediated differentiation of A549 was observed based on an increase in alkaline phosphatase activity. Simultaneously, IFN-alpha increased the expression and activity of ATP-transporters mediating MDR. Thus, the IFN-alpha down-regulation of NSCLC cell proliferation was accompanied by a potential of cells to exclude potential therapeutic substances such as chemotherapeutic agents. These effects could have a significant impact on considerations of IFN-alpha as a therapeutic agent for NSCLC.

The effect of different molecular weight hyaluronan on macrophage physiology.

OBJECTIVES: Hyaluronan, a linear glycosaminoglycan, is an abundant component of extracellular matrix. In its native form, the high-molar-mass hyaluronan polymers have an array of structural and regulatory, mainly anti-inflammatory and anti-angiogenic, functions. In contradiction, the biological effects of fragmented low molecular weight hyaluronan are suggested to be pro-angiogenic and pro-inflammatory. METHODS: The effects of highly purified pharmacological grade hyaluronan of defined molecular weights 11, 52, 87, 250 and 970 kilodaltons were tested on mouse macrophage cell lines RAW 264.7 and MHS. The surface expression of CD44 and Toll-like receptor 2, surface receptors for hyaluronan, was determined by flow cytometry. Activation of macrophages was determined based on nitric oxide and tumour necrosis factor alpha production, inducible nitric oxide synthase expression, and the activation of the nuclear factor kappa B transcriptional factor. RESULTS: Both macrophage cell lines expressed CD44 and Toll-like receptor 2, which were significantly increased by the pre-treatment of macrophages with bacterial lipopolysaccharide. Hyaluronan of any molecular weight did not activate production of nitric oxide or tumour necrosis factor alpha in any mouse macrophage cell lines. Correspondingly, hyaluronan of any tested molecular weight did not stimulate nuclear factor kappa B activation. Similarly, hyaluronan of any molecular weight neither exerted stimulatory nor inhibitory effects on macrophages pre-treated by lipopolysaccharide. CONCLUSION: Interestingly, the data does not support the current view of low molecular weight hyaluronan as a pro-inflammatory mediator for macrophages. Further studies are necessary to clarify the effects of different molecular weight hyaluronan on phagocytes.

Soluble glucomannan isolated from Candida utilis primes blood phagocytes.

It is well documented that the polysaccharide glucomannan (GM), an abundant constituent of the fungal cell wall, in the form of particulate induces strong activation of phagocytes, however, the effects of soluble GM are not known. Activation of phagocyte anti-microbial mechanisms is a crucial part of the innate host defense against invading pathogens. However, under uncontrolled inflammatory conditions they contribute to damage of surrounding tissues. Thus, to prevent these deleterious effects, the activation of phagocytes is a tightly regulated process. Therefore, in this study we analyzed the effect of soluble GM on some neutrophil functions such as reactive oxygen species production, degranulation, and receptor mobilization at the plasma membrane. Soluble GM at the tested concentrations did not stimulate oxidative burst of phagocytes directly but significantly potentiated oxidative burst in response to opsonized zymosan particles. GM induced significant phosphorylation of p47phox subunit of NADPH oxidase on Ser345. This priming effect of GM was accompanied by time and concentration dependent degranulation characterized by increased surface expression of receptors stored in neutrophil granules (CD10, CD11b, CD14, CD35, and CD66b). Degranulation was further confirmed by increase of elastase activity in media. Thus, it could be suggested that soluble GM induces priming of phagocytes connected with their degranulation, the increase of surface receptor expression, and potentiation of oxidative burst response to opsonized particles through the activation of NADPH oxidase.